1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Expr constant evaluator.
10//
11// Constant expression evaluation produces four main results:
12//
13// * A success/failure flag indicating whether constant folding was successful.
14// This is the 'bool' return value used by most of the code in this file. A
15// 'false' return value indicates that constant folding has failed, and any
16// appropriate diagnostic has already been produced.
17//
18// * An evaluated result, valid only if constant folding has not failed.
19//
20// * A flag indicating if evaluation encountered (unevaluated) side-effects.
21// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22// where it is possible to determine the evaluated result regardless.
23//
24// * A set of notes indicating why the evaluation was not a constant expression
25// (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26// too, why the expression could not be folded.
27//
28// If we are checking for a potential constant expression, failure to constant
29// fold a potential constant sub-expression will be indicated by a 'false'
30// return value (the expression could not be folded) and no diagnostic (the
31// expression is not necessarily non-constant).
32//
33//===----------------------------------------------------------------------===//
34
35#include "ByteCode/Context.h"
36#include "ByteCode/Frame.h"
37#include "ByteCode/State.h"
38#include "ExprConstShared.h"
39#include "clang/AST/APValue.h"
40#include "clang/AST/ASTContext.h"
41#include "clang/AST/ASTLambda.h"
42#include "clang/AST/Attr.h"
43#include "clang/AST/CXXInheritance.h"
44#include "clang/AST/CharUnits.h"
45#include "clang/AST/CurrentSourceLocExprScope.h"
46#include "clang/AST/Expr.h"
47#include "clang/AST/OSLog.h"
48#include "clang/AST/OptionalDiagnostic.h"
49#include "clang/AST/RecordLayout.h"
50#include "clang/AST/StmtVisitor.h"
51#include "clang/AST/TypeLoc.h"
52#include "clang/Basic/Builtins.h"
53#include "clang/Basic/DiagnosticSema.h"
54#include "clang/Basic/TargetBuiltins.h"
55#include "clang/Basic/TargetInfo.h"
56#include "llvm/ADT/APFixedPoint.h"
57#include "llvm/ADT/Sequence.h"
58#include "llvm/ADT/SmallBitVector.h"
59#include "llvm/ADT/StringExtras.h"
60#include "llvm/Support/Casting.h"
61#include "llvm/Support/Debug.h"
62#include "llvm/Support/SaveAndRestore.h"
63#include "llvm/Support/SipHash.h"
64#include "llvm/Support/TimeProfiler.h"
65#include "llvm/Support/raw_ostream.h"
66#include <cstring>
67#include <functional>
68#include <optional>
69
70#define DEBUG_TYPE "exprconstant"
71
72using namespace clang;
73using llvm::APFixedPoint;
74using llvm::APInt;
75using llvm::APSInt;
76using llvm::APFloat;
77using llvm::FixedPointSemantics;
78
79namespace {
80 struct LValue;
81 class CallStackFrame;
82 class EvalInfo;
83
84 using SourceLocExprScopeGuard =
85 CurrentSourceLocExprScope::SourceLocExprScopeGuard;
86
87 static QualType getType(APValue::LValueBase B) {
88 return B.getType();
89 }
90
91 /// Get an LValue path entry, which is known to not be an array index, as a
92 /// field declaration.
93 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
94 return dyn_cast_or_null<FieldDecl>(Val: E.getAsBaseOrMember().getPointer());
95 }
96 /// Get an LValue path entry, which is known to not be an array index, as a
97 /// base class declaration.
98 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
99 return dyn_cast_or_null<CXXRecordDecl>(Val: E.getAsBaseOrMember().getPointer());
100 }
101 /// Determine whether this LValue path entry for a base class names a virtual
102 /// base class.
103 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
104 return E.getAsBaseOrMember().getInt();
105 }
106
107 /// Given an expression, determine the type used to store the result of
108 /// evaluating that expression.
109 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
110 if (E->isPRValue())
111 return E->getType();
112 return Ctx.getLValueReferenceType(T: E->getType());
113 }
114
115 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
116 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
117 if (const FunctionDecl *DirectCallee = CE->getDirectCallee())
118 return DirectCallee->getAttr<AllocSizeAttr>();
119 if (const Decl *IndirectCallee = CE->getCalleeDecl())
120 return IndirectCallee->getAttr<AllocSizeAttr>();
121 return nullptr;
122 }
123
124 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
125 /// This will look through a single cast.
126 ///
127 /// Returns null if we couldn't unwrap a function with alloc_size.
128 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
129 if (!E->getType()->isPointerType())
130 return nullptr;
131
132 E = E->IgnoreParens();
133 // If we're doing a variable assignment from e.g. malloc(N), there will
134 // probably be a cast of some kind. In exotic cases, we might also see a
135 // top-level ExprWithCleanups. Ignore them either way.
136 if (const auto *FE = dyn_cast<FullExpr>(Val: E))
137 E = FE->getSubExpr()->IgnoreParens();
138
139 if (const auto *Cast = dyn_cast<CastExpr>(Val: E))
140 E = Cast->getSubExpr()->IgnoreParens();
141
142 if (const auto *CE = dyn_cast<CallExpr>(Val: E))
143 return getAllocSizeAttr(CE) ? CE : nullptr;
144 return nullptr;
145 }
146
147 /// Determines whether or not the given Base contains a call to a function
148 /// with the alloc_size attribute.
149 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
150 const auto *E = Base.dyn_cast<const Expr *>();
151 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
152 }
153
154 /// Determines whether the given kind of constant expression is only ever
155 /// used for name mangling. If so, it's permitted to reference things that we
156 /// can't generate code for (in particular, dllimported functions).
157 static bool isForManglingOnly(ConstantExprKind Kind) {
158 switch (Kind) {
159 case ConstantExprKind::Normal:
160 case ConstantExprKind::ClassTemplateArgument:
161 case ConstantExprKind::ImmediateInvocation:
162 // Note that non-type template arguments of class type are emitted as
163 // template parameter objects.
164 return false;
165
166 case ConstantExprKind::NonClassTemplateArgument:
167 return true;
168 }
169 llvm_unreachable("unknown ConstantExprKind");
170 }
171
172 static bool isTemplateArgument(ConstantExprKind Kind) {
173 switch (Kind) {
174 case ConstantExprKind::Normal:
175 case ConstantExprKind::ImmediateInvocation:
176 return false;
177
178 case ConstantExprKind::ClassTemplateArgument:
179 case ConstantExprKind::NonClassTemplateArgument:
180 return true;
181 }
182 llvm_unreachable("unknown ConstantExprKind");
183 }
184
185 /// The bound to claim that an array of unknown bound has.
186 /// The value in MostDerivedArraySize is undefined in this case. So, set it
187 /// to an arbitrary value that's likely to loudly break things if it's used.
188 static const uint64_t AssumedSizeForUnsizedArray =
189 std::numeric_limits<uint64_t>::max() / 2;
190
191 /// Determines if an LValue with the given LValueBase will have an unsized
192 /// array in its designator.
193 /// Find the path length and type of the most-derived subobject in the given
194 /// path, and find the size of the containing array, if any.
195 static unsigned
196 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
197 ArrayRef<APValue::LValuePathEntry> Path,
198 uint64_t &ArraySize, QualType &Type, bool &IsArray,
199 bool &FirstEntryIsUnsizedArray) {
200 // This only accepts LValueBases from APValues, and APValues don't support
201 // arrays that lack size info.
202 assert(!isBaseAnAllocSizeCall(Base) &&
203 "Unsized arrays shouldn't appear here");
204 unsigned MostDerivedLength = 0;
205 Type = getType(B: Base);
206
207 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
208 if (Type->isArrayType()) {
209 const ArrayType *AT = Ctx.getAsArrayType(T: Type);
210 Type = AT->getElementType();
211 MostDerivedLength = I + 1;
212 IsArray = true;
213
214 if (auto *CAT = dyn_cast<ConstantArrayType>(Val: AT)) {
215 ArraySize = CAT->getZExtSize();
216 } else {
217 assert(I == 0 && "unexpected unsized array designator");
218 FirstEntryIsUnsizedArray = true;
219 ArraySize = AssumedSizeForUnsizedArray;
220 }
221 } else if (Type->isAnyComplexType()) {
222 const ComplexType *CT = Type->castAs<ComplexType>();
223 Type = CT->getElementType();
224 ArraySize = 2;
225 MostDerivedLength = I + 1;
226 IsArray = true;
227 } else if (const auto *VT = Type->getAs<VectorType>()) {
228 Type = VT->getElementType();
229 ArraySize = VT->getNumElements();
230 MostDerivedLength = I + 1;
231 IsArray = true;
232 } else if (const FieldDecl *FD = getAsField(E: Path[I])) {
233 Type = FD->getType();
234 ArraySize = 0;
235 MostDerivedLength = I + 1;
236 IsArray = false;
237 } else {
238 // Path[I] describes a base class.
239 ArraySize = 0;
240 IsArray = false;
241 }
242 }
243 return MostDerivedLength;
244 }
245
246 /// A path from a glvalue to a subobject of that glvalue.
247 struct SubobjectDesignator {
248 /// True if the subobject was named in a manner not supported by C++11. Such
249 /// lvalues can still be folded, but they are not core constant expressions
250 /// and we cannot perform lvalue-to-rvalue conversions on them.
251 LLVM_PREFERRED_TYPE(bool)
252 unsigned Invalid : 1;
253
254 /// Is this a pointer one past the end of an object?
255 LLVM_PREFERRED_TYPE(bool)
256 unsigned IsOnePastTheEnd : 1;
257
258 /// Indicator of whether the first entry is an unsized array.
259 LLVM_PREFERRED_TYPE(bool)
260 unsigned FirstEntryIsAnUnsizedArray : 1;
261
262 /// Indicator of whether the most-derived object is an array element.
263 LLVM_PREFERRED_TYPE(bool)
264 unsigned MostDerivedIsArrayElement : 1;
265
266 /// The length of the path to the most-derived object of which this is a
267 /// subobject.
268 unsigned MostDerivedPathLength : 28;
269
270 /// The size of the array of which the most-derived object is an element.
271 /// This will always be 0 if the most-derived object is not an array
272 /// element. 0 is not an indicator of whether or not the most-derived object
273 /// is an array, however, because 0-length arrays are allowed.
274 ///
275 /// If the current array is an unsized array, the value of this is
276 /// undefined.
277 uint64_t MostDerivedArraySize;
278 /// The type of the most derived object referred to by this address.
279 QualType MostDerivedType;
280
281 typedef APValue::LValuePathEntry PathEntry;
282
283 /// The entries on the path from the glvalue to the designated subobject.
284 SmallVector<PathEntry, 8> Entries;
285
286 SubobjectDesignator() : Invalid(true) {}
287
288 explicit SubobjectDesignator(QualType T)
289 : Invalid(false), IsOnePastTheEnd(false),
290 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
291 MostDerivedPathLength(0), MostDerivedArraySize(0),
292 MostDerivedType(T) {}
293
294 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
295 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
296 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
297 MostDerivedPathLength(0), MostDerivedArraySize(0) {
298 assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
299 if (!Invalid) {
300 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
301 llvm::append_range(C&: Entries, R: V.getLValuePath());
302 if (V.getLValueBase()) {
303 bool IsArray = false;
304 bool FirstIsUnsizedArray = false;
305 MostDerivedPathLength = findMostDerivedSubobject(
306 Ctx, Base: V.getLValueBase(), Path: V.getLValuePath(), ArraySize&: MostDerivedArraySize,
307 Type&: MostDerivedType, IsArray, FirstEntryIsUnsizedArray&: FirstIsUnsizedArray);
308 MostDerivedIsArrayElement = IsArray;
309 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
310 }
311 }
312 }
313
314 void truncate(ASTContext &Ctx, APValue::LValueBase Base,
315 unsigned NewLength) {
316 if (Invalid)
317 return;
318
319 assert(Base && "cannot truncate path for null pointer");
320 assert(NewLength <= Entries.size() && "not a truncation");
321
322 if (NewLength == Entries.size())
323 return;
324 Entries.resize(N: NewLength);
325
326 bool IsArray = false;
327 bool FirstIsUnsizedArray = false;
328 MostDerivedPathLength = findMostDerivedSubobject(
329 Ctx, Base, Path: Entries, ArraySize&: MostDerivedArraySize, Type&: MostDerivedType, IsArray,
330 FirstEntryIsUnsizedArray&: FirstIsUnsizedArray);
331 MostDerivedIsArrayElement = IsArray;
332 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
333 }
334
335 void setInvalid() {
336 Invalid = true;
337 Entries.clear();
338 }
339
340 /// Determine whether the most derived subobject is an array without a
341 /// known bound.
342 bool isMostDerivedAnUnsizedArray() const {
343 assert(!Invalid && "Calling this makes no sense on invalid designators");
344 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
345 }
346
347 /// Determine what the most derived array's size is. Results in an assertion
348 /// failure if the most derived array lacks a size.
349 uint64_t getMostDerivedArraySize() const {
350 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size");
351 return MostDerivedArraySize;
352 }
353
354 /// Determine whether this is a one-past-the-end pointer.
355 bool isOnePastTheEnd() const {
356 assert(!Invalid);
357 if (IsOnePastTheEnd)
358 return true;
359 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
360 Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
361 MostDerivedArraySize)
362 return true;
363 return false;
364 }
365
366 /// Get the range of valid index adjustments in the form
367 /// {maximum value that can be subtracted from this pointer,
368 /// maximum value that can be added to this pointer}
369 std::pair<uint64_t, uint64_t> validIndexAdjustments() {
370 if (Invalid || isMostDerivedAnUnsizedArray())
371 return {0, 0};
372
373 // [expr.add]p4: For the purposes of these operators, a pointer to a
374 // nonarray object behaves the same as a pointer to the first element of
375 // an array of length one with the type of the object as its element type.
376 bool IsArray = MostDerivedPathLength == Entries.size() &&
377 MostDerivedIsArrayElement;
378 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
379 : (uint64_t)IsOnePastTheEnd;
380 uint64_t ArraySize =
381 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
382 return {ArrayIndex, ArraySize - ArrayIndex};
383 }
384
385 /// Check that this refers to a valid subobject.
386 bool isValidSubobject() const {
387 if (Invalid)
388 return false;
389 return !isOnePastTheEnd();
390 }
391 /// Check that this refers to a valid subobject, and if not, produce a
392 /// relevant diagnostic and set the designator as invalid.
393 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
394
395 /// Get the type of the designated object.
396 QualType getType(ASTContext &Ctx) const {
397 assert(!Invalid && "invalid designator has no subobject type");
398 return MostDerivedPathLength == Entries.size()
399 ? MostDerivedType
400 : Ctx.getRecordType(Decl: getAsBaseClass(E: Entries.back()));
401 }
402
403 /// Update this designator to refer to the first element within this array.
404 void addArrayUnchecked(const ConstantArrayType *CAT) {
405 Entries.push_back(Elt: PathEntry::ArrayIndex(Index: 0));
406
407 // This is a most-derived object.
408 MostDerivedType = CAT->getElementType();
409 MostDerivedIsArrayElement = true;
410 MostDerivedArraySize = CAT->getZExtSize();
411 MostDerivedPathLength = Entries.size();
412 }
413 /// Update this designator to refer to the first element within the array of
414 /// elements of type T. This is an array of unknown size.
415 void addUnsizedArrayUnchecked(QualType ElemTy) {
416 Entries.push_back(Elt: PathEntry::ArrayIndex(Index: 0));
417
418 MostDerivedType = ElemTy;
419 MostDerivedIsArrayElement = true;
420 // The value in MostDerivedArraySize is undefined in this case. So, set it
421 // to an arbitrary value that's likely to loudly break things if it's
422 // used.
423 MostDerivedArraySize = AssumedSizeForUnsizedArray;
424 MostDerivedPathLength = Entries.size();
425 }
426 /// Update this designator to refer to the given base or member of this
427 /// object.
428 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
429 Entries.push_back(Elt: APValue::BaseOrMemberType(D, Virtual));
430
431 // If this isn't a base class, it's a new most-derived object.
432 if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: D)) {
433 MostDerivedType = FD->getType();
434 MostDerivedIsArrayElement = false;
435 MostDerivedArraySize = 0;
436 MostDerivedPathLength = Entries.size();
437 }
438 }
439 /// Update this designator to refer to the given complex component.
440 void addComplexUnchecked(QualType EltTy, bool Imag) {
441 Entries.push_back(Elt: PathEntry::ArrayIndex(Index: Imag));
442
443 // This is technically a most-derived object, though in practice this
444 // is unlikely to matter.
445 MostDerivedType = EltTy;
446 MostDerivedIsArrayElement = true;
447 MostDerivedArraySize = 2;
448 MostDerivedPathLength = Entries.size();
449 }
450
451 void addVectorElementUnchecked(QualType EltTy, uint64_t Size,
452 uint64_t Idx) {
453 Entries.push_back(Elt: PathEntry::ArrayIndex(Index: Idx));
454 MostDerivedType = EltTy;
455 MostDerivedPathLength = Entries.size();
456 MostDerivedArraySize = 0;
457 MostDerivedIsArrayElement = false;
458 }
459
460 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
461 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
462 const APSInt &N);
463 /// Add N to the address of this subobject.
464 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
465 if (Invalid || !N) return;
466 uint64_t TruncatedN = N.extOrTrunc(width: 64).getZExtValue();
467 if (isMostDerivedAnUnsizedArray()) {
468 diagnoseUnsizedArrayPointerArithmetic(Info, E);
469 // Can't verify -- trust that the user is doing the right thing (or if
470 // not, trust that the caller will catch the bad behavior).
471 // FIXME: Should we reject if this overflows, at least?
472 Entries.back() = PathEntry::ArrayIndex(
473 Index: Entries.back().getAsArrayIndex() + TruncatedN);
474 return;
475 }
476
477 // [expr.add]p4: For the purposes of these operators, a pointer to a
478 // nonarray object behaves the same as a pointer to the first element of
479 // an array of length one with the type of the object as its element type.
480 bool IsArray = MostDerivedPathLength == Entries.size() &&
481 MostDerivedIsArrayElement;
482 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
483 : (uint64_t)IsOnePastTheEnd;
484 uint64_t ArraySize =
485 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
486
487 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
488 // Calculate the actual index in a wide enough type, so we can include
489 // it in the note.
490 N = N.extend(width: std::max<unsigned>(a: N.getBitWidth() + 1, b: 65));
491 (llvm::APInt&)N += ArrayIndex;
492 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
493 diagnosePointerArithmetic(Info, E, N);
494 setInvalid();
495 return;
496 }
497
498 ArrayIndex += TruncatedN;
499 assert(ArrayIndex <= ArraySize &&
500 "bounds check succeeded for out-of-bounds index");
501
502 if (IsArray)
503 Entries.back() = PathEntry::ArrayIndex(Index: ArrayIndex);
504 else
505 IsOnePastTheEnd = (ArrayIndex != 0);
506 }
507 };
508
509 /// A scope at the end of which an object can need to be destroyed.
510 enum class ScopeKind {
511 Block,
512 FullExpression,
513 Call
514 };
515
516 /// A reference to a particular call and its arguments.
517 struct CallRef {
518 CallRef() : OrigCallee(), CallIndex(0), Version() {}
519 CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version)
520 : OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {}
521
522 explicit operator bool() const { return OrigCallee; }
523
524 /// Get the parameter that the caller initialized, corresponding to the
525 /// given parameter in the callee.
526 const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const {
527 return OrigCallee ? OrigCallee->getParamDecl(i: PVD->getFunctionScopeIndex())
528 : PVD;
529 }
530
531 /// The callee at the point where the arguments were evaluated. This might
532 /// be different from the actual callee (a different redeclaration, or a
533 /// virtual override), but this function's parameters are the ones that
534 /// appear in the parameter map.
535 const FunctionDecl *OrigCallee;
536 /// The call index of the frame that holds the argument values.
537 unsigned CallIndex;
538 /// The version of the parameters corresponding to this call.
539 unsigned Version;
540 };
541
542 /// A stack frame in the constexpr call stack.
543 class CallStackFrame : public interp::Frame {
544 public:
545 EvalInfo &Info;
546
547 /// Parent - The caller of this stack frame.
548 CallStackFrame *Caller;
549
550 /// Callee - The function which was called.
551 const FunctionDecl *Callee;
552
553 /// This - The binding for the this pointer in this call, if any.
554 const LValue *This;
555
556 /// CallExpr - The syntactical structure of member function calls
557 const Expr *CallExpr;
558
559 /// Information on how to find the arguments to this call. Our arguments
560 /// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a
561 /// key and this value as the version.
562 CallRef Arguments;
563
564 /// Source location information about the default argument or default
565 /// initializer expression we're evaluating, if any.
566 CurrentSourceLocExprScope CurSourceLocExprScope;
567
568 // Note that we intentionally use std::map here so that references to
569 // values are stable.
570 typedef std::pair<const void *, unsigned> MapKeyTy;
571 typedef std::map<MapKeyTy, APValue> MapTy;
572 /// Temporaries - Temporary lvalues materialized within this stack frame.
573 MapTy Temporaries;
574 MapTy ConstexprUnknownAPValues;
575
576 /// CallRange - The source range of the call expression for this call.
577 SourceRange CallRange;
578
579 /// Index - The call index of this call.
580 unsigned Index;
581
582 /// The stack of integers for tracking version numbers for temporaries.
583 SmallVector<unsigned, 2> TempVersionStack = {1};
584 unsigned CurTempVersion = TempVersionStack.back();
585
586 unsigned getTempVersion() const { return TempVersionStack.back(); }
587
588 void pushTempVersion() {
589 TempVersionStack.push_back(Elt: ++CurTempVersion);
590 }
591
592 void popTempVersion() {
593 TempVersionStack.pop_back();
594 }
595
596 CallRef createCall(const FunctionDecl *Callee) {
597 return {Callee, Index, ++CurTempVersion};
598 }
599
600 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
601 // on the overall stack usage of deeply-recursing constexpr evaluations.
602 // (We should cache this map rather than recomputing it repeatedly.)
603 // But let's try this and see how it goes; we can look into caching the map
604 // as a later change.
605
606 /// LambdaCaptureFields - Mapping from captured variables/this to
607 /// corresponding data members in the closure class.
608 llvm::DenseMap<const ValueDecl *, FieldDecl *> LambdaCaptureFields;
609 FieldDecl *LambdaThisCaptureField = nullptr;
610
611 CallStackFrame(EvalInfo &Info, SourceRange CallRange,
612 const FunctionDecl *Callee, const LValue *This,
613 const Expr *CallExpr, CallRef Arguments);
614 ~CallStackFrame();
615
616 // Return the temporary for Key whose version number is Version.
617 APValue *getTemporary(const void *Key, unsigned Version) {
618 MapKeyTy KV(Key, Version);
619 auto LB = Temporaries.lower_bound(x: KV);
620 if (LB != Temporaries.end() && LB->first == KV)
621 return &LB->second;
622 return nullptr;
623 }
624
625 // Return the current temporary for Key in the map.
626 APValue *getCurrentTemporary(const void *Key) {
627 auto UB = Temporaries.upper_bound(x: MapKeyTy(Key, UINT_MAX));
628 if (UB != Temporaries.begin() && std::prev(x: UB)->first.first == Key)
629 return &std::prev(x: UB)->second;
630 return nullptr;
631 }
632
633 // Return the version number of the current temporary for Key.
634 unsigned getCurrentTemporaryVersion(const void *Key) const {
635 auto UB = Temporaries.upper_bound(x: MapKeyTy(Key, UINT_MAX));
636 if (UB != Temporaries.begin() && std::prev(x: UB)->first.first == Key)
637 return std::prev(x: UB)->first.second;
638 return 0;
639 }
640
641 /// Allocate storage for an object of type T in this stack frame.
642 /// Populates LV with a handle to the created object. Key identifies
643 /// the temporary within the stack frame, and must not be reused without
644 /// bumping the temporary version number.
645 template<typename KeyT>
646 APValue &createTemporary(const KeyT *Key, QualType T,
647 ScopeKind Scope, LValue &LV);
648
649 APValue &createConstexprUnknownAPValues(const VarDecl *Key,
650 APValue::LValueBase Base);
651
652 /// Allocate storage for a parameter of a function call made in this frame.
653 APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);
654
655 void describe(llvm::raw_ostream &OS) const override;
656
657 Frame *getCaller() const override { return Caller; }
658 SourceRange getCallRange() const override { return CallRange; }
659 const FunctionDecl *getCallee() const override { return Callee; }
660
661 bool isStdFunction() const {
662 for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
663 if (DC->isStdNamespace())
664 return true;
665 return false;
666 }
667
668 /// Whether we're in a context where [[msvc::constexpr]] evaluation is
669 /// permitted. See MSConstexprDocs for description of permitted contexts.
670 bool CanEvalMSConstexpr = false;
671
672 private:
673 APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T,
674 ScopeKind Scope);
675 };
676
677 /// Temporarily override 'this'.
678 class ThisOverrideRAII {
679 public:
680 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
681 : Frame(Frame), OldThis(Frame.This) {
682 if (Enable)
683 Frame.This = NewThis;
684 }
685 ~ThisOverrideRAII() {
686 Frame.This = OldThis;
687 }
688 private:
689 CallStackFrame &Frame;
690 const LValue *OldThis;
691 };
692
693 // A shorthand time trace scope struct, prints source range, for example
694 // {"name":"EvaluateAsRValue","args":{"detail":"<test.cc:8:21, col:25>"}}}
695 class ExprTimeTraceScope {
696 public:
697 ExprTimeTraceScope(const Expr *E, const ASTContext &Ctx, StringRef Name)
698 : TimeScope(Name, [E, &Ctx] {
699 return E->getSourceRange().printToString(SM: Ctx.getSourceManager());
700 }) {}
701
702 private:
703 llvm::TimeTraceScope TimeScope;
704 };
705
706 /// RAII object used to change the current ability of
707 /// [[msvc::constexpr]] evaulation.
708 struct MSConstexprContextRAII {
709 CallStackFrame &Frame;
710 bool OldValue;
711 explicit MSConstexprContextRAII(CallStackFrame &Frame, bool Value)
712 : Frame(Frame), OldValue(Frame.CanEvalMSConstexpr) {
713 Frame.CanEvalMSConstexpr = Value;
714 }
715
716 ~MSConstexprContextRAII() { Frame.CanEvalMSConstexpr = OldValue; }
717 };
718}
719
720static bool HandleDestruction(EvalInfo &Info, const Expr *E,
721 const LValue &This, QualType ThisType);
722static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
723 APValue::LValueBase LVBase, APValue &Value,
724 QualType T);
725
726namespace {
727 /// A cleanup, and a flag indicating whether it is lifetime-extended.
728 class Cleanup {
729 llvm::PointerIntPair<APValue*, 2, ScopeKind> Value;
730 APValue::LValueBase Base;
731 QualType T;
732
733 public:
734 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
735 ScopeKind Scope)
736 : Value(Val, Scope), Base(Base), T(T) {}
737
738 /// Determine whether this cleanup should be performed at the end of the
739 /// given kind of scope.
740 bool isDestroyedAtEndOf(ScopeKind K) const {
741 return (int)Value.getInt() >= (int)K;
742 }
743 bool endLifetime(EvalInfo &Info, bool RunDestructors) {
744 if (RunDestructors) {
745 SourceLocation Loc;
746 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
747 Loc = VD->getLocation();
748 else if (const Expr *E = Base.dyn_cast<const Expr*>())
749 Loc = E->getExprLoc();
750 return HandleDestruction(Info, Loc, LVBase: Base, Value&: *Value.getPointer(), T);
751 }
752 *Value.getPointer() = APValue();
753 return true;
754 }
755
756 bool hasSideEffect() {
757 return T.isDestructedType();
758 }
759 };
760
761 /// A reference to an object whose construction we are currently evaluating.
762 struct ObjectUnderConstruction {
763 APValue::LValueBase Base;
764 ArrayRef<APValue::LValuePathEntry> Path;
765 friend bool operator==(const ObjectUnderConstruction &LHS,
766 const ObjectUnderConstruction &RHS) {
767 return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
768 }
769 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
770 return llvm::hash_combine(args: Obj.Base, args: Obj.Path);
771 }
772 };
773 enum class ConstructionPhase {
774 None,
775 Bases,
776 AfterBases,
777 AfterFields,
778 Destroying,
779 DestroyingBases
780 };
781}
782
783namespace llvm {
784template<> struct DenseMapInfo<ObjectUnderConstruction> {
785 using Base = DenseMapInfo<APValue::LValueBase>;
786 static ObjectUnderConstruction getEmptyKey() {
787 return {.Base: Base::getEmptyKey(), .Path: {}}; }
788 static ObjectUnderConstruction getTombstoneKey() {
789 return {.Base: Base::getTombstoneKey(), .Path: {}};
790 }
791 static unsigned getHashValue(const ObjectUnderConstruction &Object) {
792 return hash_value(Obj: Object);
793 }
794 static bool isEqual(const ObjectUnderConstruction &LHS,
795 const ObjectUnderConstruction &RHS) {
796 return LHS == RHS;
797 }
798};
799}
800
801namespace {
802 /// A dynamically-allocated heap object.
803 struct DynAlloc {
804 /// The value of this heap-allocated object.
805 APValue Value;
806 /// The allocating expression; used for diagnostics. Either a CXXNewExpr
807 /// or a CallExpr (the latter is for direct calls to operator new inside
808 /// std::allocator<T>::allocate).
809 const Expr *AllocExpr = nullptr;
810
811 enum Kind {
812 New,
813 ArrayNew,
814 StdAllocator
815 };
816
817 /// Get the kind of the allocation. This must match between allocation
818 /// and deallocation.
819 Kind getKind() const {
820 if (auto *NE = dyn_cast<CXXNewExpr>(Val: AllocExpr))
821 return NE->isArray() ? ArrayNew : New;
822 assert(isa<CallExpr>(AllocExpr));
823 return StdAllocator;
824 }
825 };
826
827 struct DynAllocOrder {
828 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
829 return L.getIndex() < R.getIndex();
830 }
831 };
832
833 /// EvalInfo - This is a private struct used by the evaluator to capture
834 /// information about a subexpression as it is folded. It retains information
835 /// about the AST context, but also maintains information about the folded
836 /// expression.
837 ///
838 /// If an expression could be evaluated, it is still possible it is not a C
839 /// "integer constant expression" or constant expression. If not, this struct
840 /// captures information about how and why not.
841 ///
842 /// One bit of information passed *into* the request for constant folding
843 /// indicates whether the subexpression is "evaluated" or not according to C
844 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
845 /// evaluate the expression regardless of what the RHS is, but C only allows
846 /// certain things in certain situations.
847 class EvalInfo : public interp::State {
848 public:
849 ASTContext &Ctx;
850
851 /// EvalStatus - Contains information about the evaluation.
852 Expr::EvalStatus &EvalStatus;
853
854 /// CurrentCall - The top of the constexpr call stack.
855 CallStackFrame *CurrentCall;
856
857 /// CallStackDepth - The number of calls in the call stack right now.
858 unsigned CallStackDepth;
859
860 /// NextCallIndex - The next call index to assign.
861 unsigned NextCallIndex;
862
863 /// StepsLeft - The remaining number of evaluation steps we're permitted
864 /// to perform. This is essentially a limit for the number of statements
865 /// we will evaluate.
866 unsigned StepsLeft;
867
868 /// Enable the experimental new constant interpreter. If an expression is
869 /// not supported by the interpreter, an error is triggered.
870 bool EnableNewConstInterp;
871
872 /// BottomFrame - The frame in which evaluation started. This must be
873 /// initialized after CurrentCall and CallStackDepth.
874 CallStackFrame BottomFrame;
875
876 /// A stack of values whose lifetimes end at the end of some surrounding
877 /// evaluation frame.
878 llvm::SmallVector<Cleanup, 16> CleanupStack;
879
880 /// EvaluatingDecl - This is the declaration whose initializer is being
881 /// evaluated, if any.
882 APValue::LValueBase EvaluatingDecl;
883
884 enum class EvaluatingDeclKind {
885 None,
886 /// We're evaluating the construction of EvaluatingDecl.
887 Ctor,
888 /// We're evaluating the destruction of EvaluatingDecl.
889 Dtor,
890 };
891 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;
892
893 /// EvaluatingDeclValue - This is the value being constructed for the
894 /// declaration whose initializer is being evaluated, if any.
895 APValue *EvaluatingDeclValue;
896
897 /// Set of objects that are currently being constructed.
898 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
899 ObjectsUnderConstruction;
900
901 /// Current heap allocations, along with the location where each was
902 /// allocated. We use std::map here because we need stable addresses
903 /// for the stored APValues.
904 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;
905
906 /// The number of heap allocations performed so far in this evaluation.
907 unsigned NumHeapAllocs = 0;
908
909 struct EvaluatingConstructorRAII {
910 EvalInfo &EI;
911 ObjectUnderConstruction Object;
912 bool DidInsert;
913 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
914 bool HasBases)
915 : EI(EI), Object(Object) {
916 DidInsert =
917 EI.ObjectsUnderConstruction
918 .insert(KV: {Object, HasBases ? ConstructionPhase::Bases
919 : ConstructionPhase::AfterBases})
920 .second;
921 }
922 void finishedConstructingBases() {
923 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
924 }
925 void finishedConstructingFields() {
926 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
927 }
928 ~EvaluatingConstructorRAII() {
929 if (DidInsert) EI.ObjectsUnderConstruction.erase(Val: Object);
930 }
931 };
932
933 struct EvaluatingDestructorRAII {
934 EvalInfo &EI;
935 ObjectUnderConstruction Object;
936 bool DidInsert;
937 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
938 : EI(EI), Object(Object) {
939 DidInsert = EI.ObjectsUnderConstruction
940 .insert(KV: {Object, ConstructionPhase::Destroying})
941 .second;
942 }
943 void startedDestroyingBases() {
944 EI.ObjectsUnderConstruction[Object] =
945 ConstructionPhase::DestroyingBases;
946 }
947 ~EvaluatingDestructorRAII() {
948 if (DidInsert)
949 EI.ObjectsUnderConstruction.erase(Val: Object);
950 }
951 };
952
953 ConstructionPhase
954 isEvaluatingCtorDtor(APValue::LValueBase Base,
955 ArrayRef<APValue::LValuePathEntry> Path) {
956 return ObjectsUnderConstruction.lookup(Val: {.Base: Base, .Path: Path});
957 }
958
959 /// If we're currently speculatively evaluating, the outermost call stack
960 /// depth at which we can mutate state, otherwise 0.
961 unsigned SpeculativeEvaluationDepth = 0;
962
963 /// The current array initialization index, if we're performing array
964 /// initialization.
965 uint64_t ArrayInitIndex = -1;
966
967 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
968 /// notes attached to it will also be stored, otherwise they will not be.
969 bool HasActiveDiagnostic;
970
971 /// Have we emitted a diagnostic explaining why we couldn't constant
972 /// fold (not just why it's not strictly a constant expression)?
973 bool HasFoldFailureDiagnostic;
974
975 /// Whether we're checking that an expression is a potential constant
976 /// expression. If so, do not fail on constructs that could become constant
977 /// later on (such as a use of an undefined global).
978 bool CheckingPotentialConstantExpression = false;
979
980 /// Whether we're checking for an expression that has undefined behavior.
981 /// If so, we will produce warnings if we encounter an operation that is
982 /// always undefined.
983 ///
984 /// Note that we still need to evaluate the expression normally when this
985 /// is set; this is used when evaluating ICEs in C.
986 bool CheckingForUndefinedBehavior = false;
987
988 enum EvaluationMode {
989 /// Evaluate as a constant expression. Stop if we find that the expression
990 /// is not a constant expression.
991 EM_ConstantExpression,
992
993 /// Evaluate as a constant expression. Stop if we find that the expression
994 /// is not a constant expression. Some expressions can be retried in the
995 /// optimizer if we don't constant fold them here, but in an unevaluated
996 /// context we try to fold them immediately since the optimizer never
997 /// gets a chance to look at it.
998 EM_ConstantExpressionUnevaluated,
999
1000 /// Fold the expression to a constant. Stop if we hit a side-effect that
1001 /// we can't model.
1002 EM_ConstantFold,
1003
1004 /// Evaluate in any way we know how. Don't worry about side-effects that
1005 /// can't be modeled.
1006 EM_IgnoreSideEffects,
1007 } EvalMode;
1008
1009 /// Are we checking whether the expression is a potential constant
1010 /// expression?
1011 bool checkingPotentialConstantExpression() const override {
1012 return CheckingPotentialConstantExpression;
1013 }
1014
1015 /// Are we checking an expression for overflow?
1016 // FIXME: We should check for any kind of undefined or suspicious behavior
1017 // in such constructs, not just overflow.
1018 bool checkingForUndefinedBehavior() const override {
1019 return CheckingForUndefinedBehavior;
1020 }
1021
1022 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
1023 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
1024 CallStackDepth(0), NextCallIndex(1),
1025 StepsLeft(C.getLangOpts().ConstexprStepLimit),
1026 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
1027 BottomFrame(*this, SourceLocation(), /*Callee=*/nullptr,
1028 /*This=*/nullptr,
1029 /*CallExpr=*/nullptr, CallRef()),
1030 EvaluatingDecl((const ValueDecl *)nullptr),
1031 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
1032 HasFoldFailureDiagnostic(false), EvalMode(Mode) {}
1033
1034 ~EvalInfo() {
1035 discardCleanups();
1036 }
1037
1038 ASTContext &getASTContext() const override { return Ctx; }
1039
1040 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
1041 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
1042 EvaluatingDecl = Base;
1043 IsEvaluatingDecl = EDK;
1044 EvaluatingDeclValue = &Value;
1045 }
1046
1047 bool CheckCallLimit(SourceLocation Loc) {
1048 // Don't perform any constexpr calls (other than the call we're checking)
1049 // when checking a potential constant expression.
1050 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
1051 return false;
1052 if (NextCallIndex == 0) {
1053 // NextCallIndex has wrapped around.
1054 FFDiag(Loc, DiagId: diag::note_constexpr_call_limit_exceeded);
1055 return false;
1056 }
1057 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
1058 return true;
1059 FFDiag(Loc, DiagId: diag::note_constexpr_depth_limit_exceeded)
1060 << getLangOpts().ConstexprCallDepth;
1061 return false;
1062 }
1063
1064 bool CheckArraySize(SourceLocation Loc, unsigned BitWidth,
1065 uint64_t ElemCount, bool Diag) {
1066 // FIXME: GH63562
1067 // APValue stores array extents as unsigned,
1068 // so anything that is greater that unsigned would overflow when
1069 // constructing the array, we catch this here.
1070 if (BitWidth > ConstantArrayType::getMaxSizeBits(Context: Ctx) ||
1071 ElemCount > uint64_t(std::numeric_limits<unsigned>::max())) {
1072 if (Diag)
1073 FFDiag(Loc, DiagId: diag::note_constexpr_new_too_large) << ElemCount;
1074 return false;
1075 }
1076
1077 // FIXME: GH63562
1078 // Arrays allocate an APValue per element.
1079 // We use the number of constexpr steps as a proxy for the maximum size
1080 // of arrays to avoid exhausting the system resources, as initialization
1081 // of each element is likely to take some number of steps anyway.
1082 uint64_t Limit = Ctx.getLangOpts().ConstexprStepLimit;
1083 if (ElemCount > Limit) {
1084 if (Diag)
1085 FFDiag(Loc, DiagId: diag::note_constexpr_new_exceeds_limits)
1086 << ElemCount << Limit;
1087 return false;
1088 }
1089 return true;
1090 }
1091
1092 std::pair<CallStackFrame *, unsigned>
1093 getCallFrameAndDepth(unsigned CallIndex) {
1094 assert(CallIndex && "no call index in getCallFrameAndDepth");
1095 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
1096 // be null in this loop.
1097 unsigned Depth = CallStackDepth;
1098 CallStackFrame *Frame = CurrentCall;
1099 while (Frame->Index > CallIndex) {
1100 Frame = Frame->Caller;
1101 --Depth;
1102 }
1103 if (Frame->Index == CallIndex)
1104 return {Frame, Depth};
1105 return {nullptr, 0};
1106 }
1107
1108 bool nextStep(const Stmt *S) {
1109 if (!StepsLeft) {
1110 FFDiag(Loc: S->getBeginLoc(), DiagId: diag::note_constexpr_step_limit_exceeded);
1111 return false;
1112 }
1113 --StepsLeft;
1114 return true;
1115 }
1116
1117 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);
1118
1119 std::optional<DynAlloc *> lookupDynamicAlloc(DynamicAllocLValue DA) {
1120 std::optional<DynAlloc *> Result;
1121 auto It = HeapAllocs.find(x: DA);
1122 if (It != HeapAllocs.end())
1123 Result = &It->second;
1124 return Result;
1125 }
1126
1127 /// Get the allocated storage for the given parameter of the given call.
1128 APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) {
1129 CallStackFrame *Frame = getCallFrameAndDepth(CallIndex: Call.CallIndex).first;
1130 return Frame ? Frame->getTemporary(Key: Call.getOrigParam(PVD), Version: Call.Version)
1131 : nullptr;
1132 }
1133
1134 /// Information about a stack frame for std::allocator<T>::[de]allocate.
1135 struct StdAllocatorCaller {
1136 unsigned FrameIndex;
1137 QualType ElemType;
1138 const Expr *Call;
1139 explicit operator bool() const { return FrameIndex != 0; };
1140 };
1141
1142 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
1143 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
1144 Call = Call->Caller) {
1145 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Val: Call->Callee);
1146 if (!MD)
1147 continue;
1148 const IdentifierInfo *FnII = MD->getIdentifier();
1149 if (!FnII || !FnII->isStr(Str: FnName))
1150 continue;
1151
1152 const auto *CTSD =
1153 dyn_cast<ClassTemplateSpecializationDecl>(Val: MD->getParent());
1154 if (!CTSD)
1155 continue;
1156
1157 const IdentifierInfo *ClassII = CTSD->getIdentifier();
1158 const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
1159 if (CTSD->isInStdNamespace() && ClassII &&
1160 ClassII->isStr(Str: "allocator") && TAL.size() >= 1 &&
1161 TAL[0].getKind() == TemplateArgument::Type)
1162 return {.FrameIndex: Call->Index, .ElemType: TAL[0].getAsType(), .Call: Call->CallExpr};
1163 }
1164
1165 return {};
1166 }
1167
1168 void performLifetimeExtension() {
1169 // Disable the cleanups for lifetime-extended temporaries.
1170 llvm::erase_if(C&: CleanupStack, P: [](Cleanup &C) {
1171 return !C.isDestroyedAtEndOf(K: ScopeKind::FullExpression);
1172 });
1173 }
1174
1175 /// Throw away any remaining cleanups at the end of evaluation. If any
1176 /// cleanups would have had a side-effect, note that as an unmodeled
1177 /// side-effect and return false. Otherwise, return true.
1178 bool discardCleanups() {
1179 for (Cleanup &C : CleanupStack) {
1180 if (C.hasSideEffect() && !noteSideEffect()) {
1181 CleanupStack.clear();
1182 return false;
1183 }
1184 }
1185 CleanupStack.clear();
1186 return true;
1187 }
1188
1189 private:
1190 interp::Frame *getCurrentFrame() override { return CurrentCall; }
1191 const interp::Frame *getBottomFrame() const override { return &BottomFrame; }
1192
1193 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
1194 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }
1195
1196 void setFoldFailureDiagnostic(bool Flag) override {
1197 HasFoldFailureDiagnostic = Flag;
1198 }
1199
1200 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }
1201
1202 // If we have a prior diagnostic, it will be noting that the expression
1203 // isn't a constant expression. This diagnostic is more important,
1204 // unless we require this evaluation to produce a constant expression.
1205 //
1206 // FIXME: We might want to show both diagnostics to the user in
1207 // EM_ConstantFold mode.
1208 bool hasPriorDiagnostic() override {
1209 if (!EvalStatus.Diag->empty()) {
1210 switch (EvalMode) {
1211 case EM_ConstantFold:
1212 case EM_IgnoreSideEffects:
1213 if (!HasFoldFailureDiagnostic)
1214 break;
1215 // We've already failed to fold something. Keep that diagnostic.
1216 [[fallthrough]];
1217 case EM_ConstantExpression:
1218 case EM_ConstantExpressionUnevaluated:
1219 setActiveDiagnostic(false);
1220 return true;
1221 }
1222 }
1223 return false;
1224 }
1225
1226 unsigned getCallStackDepth() override { return CallStackDepth; }
1227
1228 public:
1229 /// Should we continue evaluation after encountering a side-effect that we
1230 /// couldn't model?
1231 bool keepEvaluatingAfterSideEffect() const override {
1232 switch (EvalMode) {
1233 case EM_IgnoreSideEffects:
1234 return true;
1235
1236 case EM_ConstantExpression:
1237 case EM_ConstantExpressionUnevaluated:
1238 case EM_ConstantFold:
1239 // By default, assume any side effect might be valid in some other
1240 // evaluation of this expression from a different context.
1241 return checkingPotentialConstantExpression() ||
1242 checkingForUndefinedBehavior();
1243 }
1244 llvm_unreachable("Missed EvalMode case");
1245 }
1246
1247 /// Note that we have had a side-effect, and determine whether we should
1248 /// keep evaluating.
1249 bool noteSideEffect() override {
1250 EvalStatus.HasSideEffects = true;
1251 return keepEvaluatingAfterSideEffect();
1252 }
1253
1254 /// Should we continue evaluation after encountering undefined behavior?
1255 bool keepEvaluatingAfterUndefinedBehavior() {
1256 switch (EvalMode) {
1257 case EM_IgnoreSideEffects:
1258 case EM_ConstantFold:
1259 return true;
1260
1261 case EM_ConstantExpression:
1262 case EM_ConstantExpressionUnevaluated:
1263 return checkingForUndefinedBehavior();
1264 }
1265 llvm_unreachable("Missed EvalMode case");
1266 }
1267
1268 /// Note that we hit something that was technically undefined behavior, but
1269 /// that we can evaluate past it (such as signed overflow or floating-point
1270 /// division by zero.)
1271 bool noteUndefinedBehavior() override {
1272 EvalStatus.HasUndefinedBehavior = true;
1273 return keepEvaluatingAfterUndefinedBehavior();
1274 }
1275
1276 /// Should we continue evaluation as much as possible after encountering a
1277 /// construct which can't be reduced to a value?
1278 bool keepEvaluatingAfterFailure() const override {
1279 if (!StepsLeft)
1280 return false;
1281
1282 switch (EvalMode) {
1283 case EM_ConstantExpression:
1284 case EM_ConstantExpressionUnevaluated:
1285 case EM_ConstantFold:
1286 case EM_IgnoreSideEffects:
1287 return checkingPotentialConstantExpression() ||
1288 checkingForUndefinedBehavior();
1289 }
1290 llvm_unreachable("Missed EvalMode case");
1291 }
1292
1293 /// Notes that we failed to evaluate an expression that other expressions
1294 /// directly depend on, and determine if we should keep evaluating. This
1295 /// should only be called if we actually intend to keep evaluating.
1296 ///
1297 /// Call noteSideEffect() instead if we may be able to ignore the value that
1298 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
1299 ///
1300 /// (Foo(), 1) // use noteSideEffect
1301 /// (Foo() || true) // use noteSideEffect
1302 /// Foo() + 1 // use noteFailure
1303 [[nodiscard]] bool noteFailure() {
1304 // Failure when evaluating some expression often means there is some
1305 // subexpression whose evaluation was skipped. Therefore, (because we
1306 // don't track whether we skipped an expression when unwinding after an
1307 // evaluation failure) every evaluation failure that bubbles up from a
1308 // subexpression implies that a side-effect has potentially happened. We
1309 // skip setting the HasSideEffects flag to true until we decide to
1310 // continue evaluating after that point, which happens here.
1311 bool KeepGoing = keepEvaluatingAfterFailure();
1312 EvalStatus.HasSideEffects |= KeepGoing;
1313 return KeepGoing;
1314 }
1315
1316 class ArrayInitLoopIndex {
1317 EvalInfo &Info;
1318 uint64_t OuterIndex;
1319
1320 public:
1321 ArrayInitLoopIndex(EvalInfo &Info)
1322 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
1323 Info.ArrayInitIndex = 0;
1324 }
1325 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
1326
1327 operator uint64_t&() { return Info.ArrayInitIndex; }
1328 };
1329 };
1330
1331 /// Object used to treat all foldable expressions as constant expressions.
1332 struct FoldConstant {
1333 EvalInfo &Info;
1334 bool Enabled;
1335 bool HadNoPriorDiags;
1336 EvalInfo::EvaluationMode OldMode;
1337
1338 explicit FoldConstant(EvalInfo &Info, bool Enabled)
1339 : Info(Info),
1340 Enabled(Enabled),
1341 HadNoPriorDiags(Info.EvalStatus.Diag &&
1342 Info.EvalStatus.Diag->empty() &&
1343 !Info.EvalStatus.HasSideEffects),
1344 OldMode(Info.EvalMode) {
1345 if (Enabled)
1346 Info.EvalMode = EvalInfo::EM_ConstantFold;
1347 }
1348 void keepDiagnostics() { Enabled = false; }
1349 ~FoldConstant() {
1350 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
1351 !Info.EvalStatus.HasSideEffects)
1352 Info.EvalStatus.Diag->clear();
1353 Info.EvalMode = OldMode;
1354 }
1355 };
1356
1357 /// RAII object used to set the current evaluation mode to ignore
1358 /// side-effects.
1359 struct IgnoreSideEffectsRAII {
1360 EvalInfo &Info;
1361 EvalInfo::EvaluationMode OldMode;
1362 explicit IgnoreSideEffectsRAII(EvalInfo &Info)
1363 : Info(Info), OldMode(Info.EvalMode) {
1364 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
1365 }
1366
1367 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
1368 };
1369
1370 /// RAII object used to optionally suppress diagnostics and side-effects from
1371 /// a speculative evaluation.
1372 class SpeculativeEvaluationRAII {
1373 EvalInfo *Info = nullptr;
1374 Expr::EvalStatus OldStatus;
1375 unsigned OldSpeculativeEvaluationDepth = 0;
1376
1377 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
1378 Info = Other.Info;
1379 OldStatus = Other.OldStatus;
1380 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
1381 Other.Info = nullptr;
1382 }
1383
1384 void maybeRestoreState() {
1385 if (!Info)
1386 return;
1387
1388 Info->EvalStatus = OldStatus;
1389 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
1390 }
1391
1392 public:
1393 SpeculativeEvaluationRAII() = default;
1394
1395 SpeculativeEvaluationRAII(
1396 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1397 : Info(&Info), OldStatus(Info.EvalStatus),
1398 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
1399 Info.EvalStatus.Diag = NewDiag;
1400 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
1401 }
1402
1403 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1404 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1405 moveFromAndCancel(Other: std::move(Other));
1406 }
1407
1408 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1409 maybeRestoreState();
1410 moveFromAndCancel(Other: std::move(Other));
1411 return *this;
1412 }
1413
1414 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1415 };
1416
1417 /// RAII object wrapping a full-expression or block scope, and handling
1418 /// the ending of the lifetime of temporaries created within it.
1419 template<ScopeKind Kind>
1420 class ScopeRAII {
1421 EvalInfo &Info;
1422 unsigned OldStackSize;
1423 public:
1424 ScopeRAII(EvalInfo &Info)
1425 : Info(Info), OldStackSize(Info.CleanupStack.size()) {
1426 // Push a new temporary version. This is needed to distinguish between
1427 // temporaries created in different iterations of a loop.
1428 Info.CurrentCall->pushTempVersion();
1429 }
1430 bool destroy(bool RunDestructors = true) {
1431 bool OK = cleanup(Info, RunDestructors, OldStackSize);
1432 OldStackSize = -1U;
1433 return OK;
1434 }
1435 ~ScopeRAII() {
1436 if (OldStackSize != -1U)
1437 destroy(RunDestructors: false);
1438 // Body moved to a static method to encourage the compiler to inline away
1439 // instances of this class.
1440 Info.CurrentCall->popTempVersion();
1441 }
1442 private:
1443 static bool cleanup(EvalInfo &Info, bool RunDestructors,
1444 unsigned OldStackSize) {
1445 assert(OldStackSize <= Info.CleanupStack.size() &&
1446 "running cleanups out of order?");
1447
1448 // Run all cleanups for a block scope, and non-lifetime-extended cleanups
1449 // for a full-expression scope.
1450 bool Success = true;
1451 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
1452 if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(K: Kind)) {
1453 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
1454 Success = false;
1455 break;
1456 }
1457 }
1458 }
1459
1460 // Compact any retained cleanups.
1461 auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
1462 if (Kind != ScopeKind::Block)
1463 NewEnd =
1464 std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) {
1465 return C.isDestroyedAtEndOf(K: Kind);
1466 });
1467 Info.CleanupStack.erase(CS: NewEnd, CE: Info.CleanupStack.end());
1468 return Success;
1469 }
1470 };
1471 typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII;
1472 typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII;
1473 typedef ScopeRAII<ScopeKind::Call> CallScopeRAII;
1474}
1475
1476bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1477 CheckSubobjectKind CSK) {
1478 if (Invalid)
1479 return false;
1480 if (isOnePastTheEnd()) {
1481 Info.CCEDiag(E, DiagId: diag::note_constexpr_past_end_subobject)
1482 << CSK;
1483 setInvalid();
1484 return false;
1485 }
1486 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
1487 // must actually be at least one array element; even a VLA cannot have a
1488 // bound of zero. And if our index is nonzero, we already had a CCEDiag.
1489 return true;
1490}
1491
1492void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
1493 const Expr *E) {
1494 Info.CCEDiag(E, DiagId: diag::note_constexpr_unsized_array_indexed);
1495 // Do not set the designator as invalid: we can represent this situation,
1496 // and correct handling of __builtin_object_size requires us to do so.
1497}
1498
1499void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1500 const Expr *E,
1501 const APSInt &N) {
1502 // If we're complaining, we must be able to statically determine the size of
1503 // the most derived array.
1504 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1505 Info.CCEDiag(E, DiagId: diag::note_constexpr_array_index)
1506 << N << /*array*/ 0
1507 << static_cast<unsigned>(getMostDerivedArraySize());
1508 else
1509 Info.CCEDiag(E, DiagId: diag::note_constexpr_array_index)
1510 << N << /*non-array*/ 1;
1511 setInvalid();
1512}
1513
1514CallStackFrame::CallStackFrame(EvalInfo &Info, SourceRange CallRange,
1515 const FunctionDecl *Callee, const LValue *This,
1516 const Expr *CallExpr, CallRef Call)
1517 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1518 CallExpr(CallExpr), Arguments(Call), CallRange(CallRange),
1519 Index(Info.NextCallIndex++) {
1520 Info.CurrentCall = this;
1521 ++Info.CallStackDepth;
1522}
1523
1524CallStackFrame::~CallStackFrame() {
1525 assert(Info.CurrentCall == this && "calls retired out of order");
1526 --Info.CallStackDepth;
1527 Info.CurrentCall = Caller;
1528}
1529
1530static bool isRead(AccessKinds AK) {
1531 return AK == AK_Read || AK == AK_ReadObjectRepresentation ||
1532 AK == AK_IsWithinLifetime;
1533}
1534
1535static bool isModification(AccessKinds AK) {
1536 switch (AK) {
1537 case AK_Read:
1538 case AK_ReadObjectRepresentation:
1539 case AK_MemberCall:
1540 case AK_DynamicCast:
1541 case AK_TypeId:
1542 case AK_IsWithinLifetime:
1543 return false;
1544 case AK_Assign:
1545 case AK_Increment:
1546 case AK_Decrement:
1547 case AK_Construct:
1548 case AK_Destroy:
1549 return true;
1550 }
1551 llvm_unreachable("unknown access kind");
1552}
1553
1554static bool isAnyAccess(AccessKinds AK) {
1555 return isRead(AK) || isModification(AK);
1556}
1557
1558/// Is this an access per the C++ definition?
1559static bool isFormalAccess(AccessKinds AK) {
1560 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy &&
1561 AK != AK_IsWithinLifetime;
1562}
1563
1564/// Is this kind of axcess valid on an indeterminate object value?
1565static bool isValidIndeterminateAccess(AccessKinds AK) {
1566 switch (AK) {
1567 case AK_Read:
1568 case AK_Increment:
1569 case AK_Decrement:
1570 // These need the object's value.
1571 return false;
1572
1573 case AK_IsWithinLifetime:
1574 case AK_ReadObjectRepresentation:
1575 case AK_Assign:
1576 case AK_Construct:
1577 case AK_Destroy:
1578 // Construction and destruction don't need the value.
1579 return true;
1580
1581 case AK_MemberCall:
1582 case AK_DynamicCast:
1583 case AK_TypeId:
1584 // These aren't really meaningful on scalars.
1585 return true;
1586 }
1587 llvm_unreachable("unknown access kind");
1588}
1589
1590namespace {
1591 struct ComplexValue {
1592 private:
1593 bool IsInt;
1594
1595 public:
1596 APSInt IntReal, IntImag;
1597 APFloat FloatReal, FloatImag;
1598
1599 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1600
1601 void makeComplexFloat() { IsInt = false; }
1602 bool isComplexFloat() const { return !IsInt; }
1603 APFloat &getComplexFloatReal() { return FloatReal; }
1604 APFloat &getComplexFloatImag() { return FloatImag; }
1605
1606 void makeComplexInt() { IsInt = true; }
1607 bool isComplexInt() const { return IsInt; }
1608 APSInt &getComplexIntReal() { return IntReal; }
1609 APSInt &getComplexIntImag() { return IntImag; }
1610
1611 void moveInto(APValue &v) const {
1612 if (isComplexFloat())
1613 v = APValue(FloatReal, FloatImag);
1614 else
1615 v = APValue(IntReal, IntImag);
1616 }
1617 void setFrom(const APValue &v) {
1618 assert(v.isComplexFloat() || v.isComplexInt());
1619 if (v.isComplexFloat()) {
1620 makeComplexFloat();
1621 FloatReal = v.getComplexFloatReal();
1622 FloatImag = v.getComplexFloatImag();
1623 } else {
1624 makeComplexInt();
1625 IntReal = v.getComplexIntReal();
1626 IntImag = v.getComplexIntImag();
1627 }
1628 }
1629 };
1630
1631 struct LValue {
1632 APValue::LValueBase Base;
1633 CharUnits Offset;
1634 SubobjectDesignator Designator;
1635 bool IsNullPtr : 1;
1636 bool InvalidBase : 1;
1637 // P2280R4 track if we have an unknown reference or pointer.
1638 bool AllowConstexprUnknown = false;
1639
1640 const APValue::LValueBase getLValueBase() const { return Base; }
1641 bool allowConstexprUnknown() const { return AllowConstexprUnknown; }
1642 CharUnits &getLValueOffset() { return Offset; }
1643 const CharUnits &getLValueOffset() const { return Offset; }
1644 SubobjectDesignator &getLValueDesignator() { return Designator; }
1645 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1646 bool isNullPointer() const { return IsNullPtr;}
1647
1648 unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
1649 unsigned getLValueVersion() const { return Base.getVersion(); }
1650
1651 void moveInto(APValue &V) const {
1652 if (Designator.Invalid)
1653 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
1654 else {
1655 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1656 V = APValue(Base, Offset, Designator.Entries,
1657 Designator.IsOnePastTheEnd, IsNullPtr);
1658 }
1659 if (AllowConstexprUnknown)
1660 V.setConstexprUnknown();
1661 }
1662 void setFrom(ASTContext &Ctx, const APValue &V) {
1663 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1664 Base = V.getLValueBase();
1665 Offset = V.getLValueOffset();
1666 InvalidBase = false;
1667 Designator = SubobjectDesignator(Ctx, V);
1668 IsNullPtr = V.isNullPointer();
1669 AllowConstexprUnknown = V.allowConstexprUnknown();
1670 }
1671
1672 void set(APValue::LValueBase B, bool BInvalid = false) {
1673#ifndef NDEBUG
1674 // We only allow a few types of invalid bases. Enforce that here.
1675 if (BInvalid) {
1676 const auto *E = B.get<const Expr *>();
1677 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1678 "Unexpected type of invalid base");
1679 }
1680#endif
1681
1682 Base = B;
1683 Offset = CharUnits::fromQuantity(Quantity: 0);
1684 InvalidBase = BInvalid;
1685 Designator = SubobjectDesignator(getType(B));
1686 IsNullPtr = false;
1687 AllowConstexprUnknown = false;
1688 }
1689
1690 void setNull(ASTContext &Ctx, QualType PointerTy) {
1691 Base = (const ValueDecl *)nullptr;
1692 Offset =
1693 CharUnits::fromQuantity(Quantity: Ctx.getTargetNullPointerValue(QT: PointerTy));
1694 InvalidBase = false;
1695 Designator = SubobjectDesignator(PointerTy->getPointeeType());
1696 IsNullPtr = true;
1697 AllowConstexprUnknown = false;
1698 }
1699
1700 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1701 set(B, BInvalid: true);
1702 }
1703
1704 std::string toString(ASTContext &Ctx, QualType T) const {
1705 APValue Printable;
1706 moveInto(V&: Printable);
1707 return Printable.getAsString(Ctx, Ty: T);
1708 }
1709
1710 private:
1711 // Check that this LValue is not based on a null pointer. If it is, produce
1712 // a diagnostic and mark the designator as invalid.
1713 template <typename GenDiagType>
1714 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
1715 if (Designator.Invalid)
1716 return false;
1717 if (IsNullPtr) {
1718 GenDiag();
1719 Designator.setInvalid();
1720 return false;
1721 }
1722 return true;
1723 }
1724
1725 public:
1726 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1727 CheckSubobjectKind CSK) {
1728 return checkNullPointerDiagnosingWith(GenDiag: [&Info, E, CSK] {
1729 Info.CCEDiag(E, DiagId: diag::note_constexpr_null_subobject) << CSK;
1730 });
1731 }
1732
1733 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
1734 AccessKinds AK) {
1735 return checkNullPointerDiagnosingWith(GenDiag: [&Info, E, AK] {
1736 Info.FFDiag(E, DiagId: diag::note_constexpr_access_null) << AK;
1737 });
1738 }
1739
1740 // Check this LValue refers to an object. If not, set the designator to be
1741 // invalid and emit a diagnostic.
1742 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1743 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1744 Designator.checkSubobject(Info, E, CSK);
1745 }
1746
1747 void addDecl(EvalInfo &Info, const Expr *E,
1748 const Decl *D, bool Virtual = false) {
1749 if (checkSubobject(Info, E, CSK: isa<FieldDecl>(Val: D) ? CSK_Field : CSK_Base))
1750 Designator.addDeclUnchecked(D, Virtual);
1751 }
1752 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
1753 if (!Designator.Entries.empty()) {
1754 Info.CCEDiag(E, DiagId: diag::note_constexpr_unsupported_unsized_array);
1755 Designator.setInvalid();
1756 return;
1757 }
1758 if (checkSubobject(Info, E, CSK: CSK_ArrayToPointer)) {
1759 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType());
1760 Designator.FirstEntryIsAnUnsizedArray = true;
1761 Designator.addUnsizedArrayUnchecked(ElemTy);
1762 }
1763 }
1764 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1765 if (checkSubobject(Info, E, CSK: CSK_ArrayToPointer))
1766 Designator.addArrayUnchecked(CAT);
1767 }
1768 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1769 if (checkSubobject(Info, E, CSK: Imag ? CSK_Imag : CSK_Real))
1770 Designator.addComplexUnchecked(EltTy, Imag);
1771 }
1772 void addVectorElement(EvalInfo &Info, const Expr *E, QualType EltTy,
1773 uint64_t Size, uint64_t Idx) {
1774 if (checkSubobject(Info, E, CSK: CSK_VectorElement))
1775 Designator.addVectorElementUnchecked(EltTy, Size, Idx);
1776 }
1777 void clearIsNullPointer() {
1778 IsNullPtr = false;
1779 }
1780 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1781 const APSInt &Index, CharUnits ElementSize) {
1782 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1783 // but we're not required to diagnose it and it's valid in C++.)
1784 if (!Index)
1785 return;
1786
1787 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1788 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1789 // offsets.
1790 uint64_t Offset64 = Offset.getQuantity();
1791 uint64_t ElemSize64 = ElementSize.getQuantity();
1792 uint64_t Index64 = Index.extOrTrunc(width: 64).getZExtValue();
1793 Offset = CharUnits::fromQuantity(Quantity: Offset64 + ElemSize64 * Index64);
1794
1795 if (checkNullPointer(Info, E, CSK: CSK_ArrayIndex))
1796 Designator.adjustIndex(Info, E, N: Index);
1797 clearIsNullPointer();
1798 }
1799 void adjustOffset(CharUnits N) {
1800 Offset += N;
1801 if (N.getQuantity())
1802 clearIsNullPointer();
1803 }
1804 };
1805
1806 struct MemberPtr {
1807 MemberPtr() {}
1808 explicit MemberPtr(const ValueDecl *Decl)
1809 : DeclAndIsDerivedMember(Decl, false) {}
1810
1811 /// The member or (direct or indirect) field referred to by this member
1812 /// pointer, or 0 if this is a null member pointer.
1813 const ValueDecl *getDecl() const {
1814 return DeclAndIsDerivedMember.getPointer();
1815 }
1816 /// Is this actually a member of some type derived from the relevant class?
1817 bool isDerivedMember() const {
1818 return DeclAndIsDerivedMember.getInt();
1819 }
1820 /// Get the class which the declaration actually lives in.
1821 const CXXRecordDecl *getContainingRecord() const {
1822 return cast<CXXRecordDecl>(
1823 Val: DeclAndIsDerivedMember.getPointer()->getDeclContext());
1824 }
1825
1826 void moveInto(APValue &V) const {
1827 V = APValue(getDecl(), isDerivedMember(), Path);
1828 }
1829 void setFrom(const APValue &V) {
1830 assert(V.isMemberPointer());
1831 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1832 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1833 Path.clear();
1834 llvm::append_range(C&: Path, R: V.getMemberPointerPath());
1835 }
1836
1837 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1838 /// whether the member is a member of some class derived from the class type
1839 /// of the member pointer.
1840 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1841 /// Path - The path of base/derived classes from the member declaration's
1842 /// class (exclusive) to the class type of the member pointer (inclusive).
1843 SmallVector<const CXXRecordDecl*, 4> Path;
1844
1845 /// Perform a cast towards the class of the Decl (either up or down the
1846 /// hierarchy).
1847 bool castBack(const CXXRecordDecl *Class) {
1848 assert(!Path.empty());
1849 const CXXRecordDecl *Expected;
1850 if (Path.size() >= 2)
1851 Expected = Path[Path.size() - 2];
1852 else
1853 Expected = getContainingRecord();
1854 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1855 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1856 // if B does not contain the original member and is not a base or
1857 // derived class of the class containing the original member, the result
1858 // of the cast is undefined.
1859 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1860 // (D::*). We consider that to be a language defect.
1861 return false;
1862 }
1863 Path.pop_back();
1864 return true;
1865 }
1866 /// Perform a base-to-derived member pointer cast.
1867 bool castToDerived(const CXXRecordDecl *Derived) {
1868 if (!getDecl())
1869 return true;
1870 if (!isDerivedMember()) {
1871 Path.push_back(Elt: Derived);
1872 return true;
1873 }
1874 if (!castBack(Class: Derived))
1875 return false;
1876 if (Path.empty())
1877 DeclAndIsDerivedMember.setInt(false);
1878 return true;
1879 }
1880 /// Perform a derived-to-base member pointer cast.
1881 bool castToBase(const CXXRecordDecl *Base) {
1882 if (!getDecl())
1883 return true;
1884 if (Path.empty())
1885 DeclAndIsDerivedMember.setInt(true);
1886 if (isDerivedMember()) {
1887 Path.push_back(Elt: Base);
1888 return true;
1889 }
1890 return castBack(Class: Base);
1891 }
1892 };
1893
1894 /// Compare two member pointers, which are assumed to be of the same type.
1895 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1896 if (!LHS.getDecl() || !RHS.getDecl())
1897 return !LHS.getDecl() && !RHS.getDecl();
1898 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1899 return false;
1900 return LHS.Path == RHS.Path;
1901 }
1902}
1903
1904static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1905static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1906 const LValue &This, const Expr *E,
1907 bool AllowNonLiteralTypes = false);
1908static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1909 bool InvalidBaseOK = false);
1910static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1911 bool InvalidBaseOK = false);
1912static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1913 EvalInfo &Info);
1914static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1915static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1916static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1917 EvalInfo &Info);
1918static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1919static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1920static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1921 EvalInfo &Info);
1922static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1923static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result,
1924 EvalInfo &Info,
1925 std::string *StringResult = nullptr);
1926
1927/// Evaluate an integer or fixed point expression into an APResult.
1928static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
1929 EvalInfo &Info);
1930
1931/// Evaluate only a fixed point expression into an APResult.
1932static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
1933 EvalInfo &Info);
1934
1935//===----------------------------------------------------------------------===//
1936// Misc utilities
1937//===----------------------------------------------------------------------===//
1938
1939/// Negate an APSInt in place, converting it to a signed form if necessary, and
1940/// preserving its value (by extending by up to one bit as needed).
1941static void negateAsSigned(APSInt &Int) {
1942 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1943 Int = Int.extend(width: Int.getBitWidth() + 1);
1944 Int.setIsSigned(true);
1945 }
1946 Int = -Int;
1947}
1948
1949template<typename KeyT>
1950APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
1951 ScopeKind Scope, LValue &LV) {
1952 unsigned Version = getTempVersion();
1953 APValue::LValueBase Base(Key, Index, Version);
1954 LV.set(B: Base);
1955 return createLocal(Base, Key, T, Scope);
1956}
1957
1958APValue &
1959CallStackFrame::createConstexprUnknownAPValues(const VarDecl *Key,
1960 APValue::LValueBase Base) {
1961 APValue &Result = ConstexprUnknownAPValues[MapKeyTy(Key, Base.getVersion())];
1962 Result = APValue(Base, CharUnits::Zero(), APValue::ConstexprUnknown{});
1963
1964 return Result;
1965}
1966
1967/// Allocate storage for a parameter of a function call made in this frame.
1968APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
1969 LValue &LV) {
1970 assert(Args.CallIndex == Index && "creating parameter in wrong frame");
1971 APValue::LValueBase Base(PVD, Index, Args.Version);
1972 LV.set(B: Base);
1973 // We always destroy parameters at the end of the call, even if we'd allow
1974 // them to live to the end of the full-expression at runtime, in order to
1975 // give portable results and match other compilers.
1976 return createLocal(Base, Key: PVD, T: PVD->getType(), Scope: ScopeKind::Call);
1977}
1978
1979APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key,
1980 QualType T, ScopeKind Scope) {
1981 assert(Base.getCallIndex() == Index && "lvalue for wrong frame");
1982 unsigned Version = Base.getVersion();
1983 APValue &Result = Temporaries[MapKeyTy(Key, Version)];
1984 assert(Result.isAbsent() && "local created multiple times");
1985
1986 // If we're creating a local immediately in the operand of a speculative
1987 // evaluation, don't register a cleanup to be run outside the speculative
1988 // evaluation context, since we won't actually be able to initialize this
1989 // object.
1990 if (Index <= Info.SpeculativeEvaluationDepth) {
1991 if (T.isDestructedType())
1992 Info.noteSideEffect();
1993 } else {
1994 Info.CleanupStack.push_back(Elt: Cleanup(&Result, Base, T, Scope));
1995 }
1996 return Result;
1997}
1998
1999APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
2000 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
2001 FFDiag(E, DiagId: diag::note_constexpr_heap_alloc_limit_exceeded);
2002 return nullptr;
2003 }
2004
2005 DynamicAllocLValue DA(NumHeapAllocs++);
2006 LV.set(B: APValue::LValueBase::getDynamicAlloc(LV: DA, Type: T));
2007 auto Result = HeapAllocs.emplace(args: std::piecewise_construct,
2008 args: std::forward_as_tuple(args&: DA), args: std::tuple<>());
2009 assert(Result.second && "reused a heap alloc index?");
2010 Result.first->second.AllocExpr = E;
2011 return &Result.first->second.Value;
2012}
2013
2014/// Produce a string describing the given constexpr call.
2015void CallStackFrame::describe(raw_ostream &Out) const {
2016 unsigned ArgIndex = 0;
2017 bool IsMemberCall =
2018 isa<CXXMethodDecl>(Val: Callee) && !isa<CXXConstructorDecl>(Val: Callee) &&
2019 cast<CXXMethodDecl>(Val: Callee)->isImplicitObjectMemberFunction();
2020
2021 if (!IsMemberCall)
2022 Callee->getNameForDiagnostic(OS&: Out, Policy: Info.Ctx.getPrintingPolicy(),
2023 /*Qualified=*/false);
2024
2025 if (This && IsMemberCall) {
2026 if (const auto *MCE = dyn_cast_if_present<CXXMemberCallExpr>(Val: CallExpr)) {
2027 const Expr *Object = MCE->getImplicitObjectArgument();
2028 Object->printPretty(OS&: Out, /*Helper=*/nullptr, Policy: Info.Ctx.getPrintingPolicy(),
2029 /*Indentation=*/0);
2030 if (Object->getType()->isPointerType())
2031 Out << "->";
2032 else
2033 Out << ".";
2034 } else if (const auto *OCE =
2035 dyn_cast_if_present<CXXOperatorCallExpr>(Val: CallExpr)) {
2036 OCE->getArg(Arg: 0)->printPretty(OS&: Out, /*Helper=*/nullptr,
2037 Policy: Info.Ctx.getPrintingPolicy(),
2038 /*Indentation=*/0);
2039 Out << ".";
2040 } else {
2041 APValue Val;
2042 This->moveInto(V&: Val);
2043 Val.printPretty(
2044 OS&: Out, Ctx: Info.Ctx,
2045 Ty: Info.Ctx.getLValueReferenceType(T: This->Designator.MostDerivedType));
2046 Out << ".";
2047 }
2048 Callee->getNameForDiagnostic(OS&: Out, Policy: Info.Ctx.getPrintingPolicy(),
2049 /*Qualified=*/false);
2050 IsMemberCall = false;
2051 }
2052
2053 Out << '(';
2054
2055 for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
2056 E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
2057 if (ArgIndex > (unsigned)IsMemberCall)
2058 Out << ", ";
2059
2060 const ParmVarDecl *Param = *I;
2061 APValue *V = Info.getParamSlot(Call: Arguments, PVD: Param);
2062 if (V)
2063 V->printPretty(OS&: Out, Ctx: Info.Ctx, Ty: Param->getType());
2064 else
2065 Out << "<...>";
2066
2067 if (ArgIndex == 0 && IsMemberCall)
2068 Out << "->" << *Callee << '(';
2069 }
2070
2071 Out << ')';
2072}
2073
2074/// Evaluate an expression to see if it had side-effects, and discard its
2075/// result.
2076/// \return \c true if the caller should keep evaluating.
2077static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
2078 assert(!E->isValueDependent());
2079 APValue Scratch;
2080 if (!Evaluate(Result&: Scratch, Info, E))
2081 // We don't need the value, but we might have skipped a side effect here.
2082 return Info.noteSideEffect();
2083 return true;
2084}
2085
2086/// Should this call expression be treated as forming an opaque constant?
2087static bool IsOpaqueConstantCall(const CallExpr *E) {
2088 unsigned Builtin = E->getBuiltinCallee();
2089 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
2090 Builtin == Builtin::BI__builtin___NSStringMakeConstantString ||
2091 Builtin == Builtin::BI__builtin_ptrauth_sign_constant ||
2092 Builtin == Builtin::BI__builtin_function_start);
2093}
2094
2095static bool IsOpaqueConstantCall(const LValue &LVal) {
2096 const auto *BaseExpr =
2097 llvm::dyn_cast_if_present<CallExpr>(Val: LVal.Base.dyn_cast<const Expr *>());
2098 return BaseExpr && IsOpaqueConstantCall(E: BaseExpr);
2099}
2100
2101static bool IsGlobalLValue(APValue::LValueBase B) {
2102 // C++11 [expr.const]p3 An address constant expression is a prvalue core
2103 // constant expression of pointer type that evaluates to...
2104
2105 // ... a null pointer value, or a prvalue core constant expression of type
2106 // std::nullptr_t.
2107 if (!B)
2108 return true;
2109
2110 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
2111 // ... the address of an object with static storage duration,
2112 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
2113 return VD->hasGlobalStorage();
2114 if (isa<TemplateParamObjectDecl>(Val: D))
2115 return true;
2116 // ... the address of a function,
2117 // ... the address of a GUID [MS extension],
2118 // ... the address of an unnamed global constant
2119 return isa<FunctionDecl, MSGuidDecl, UnnamedGlobalConstantDecl>(Val: D);
2120 }
2121
2122 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
2123 return true;
2124
2125 const Expr *E = B.get<const Expr*>();
2126 switch (E->getStmtClass()) {
2127 default:
2128 return false;
2129 case Expr::CompoundLiteralExprClass: {
2130 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(Val: E);
2131 return CLE->isFileScope() && CLE->isLValue();
2132 }
2133 case Expr::MaterializeTemporaryExprClass:
2134 // A materialized temporary might have been lifetime-extended to static
2135 // storage duration.
2136 return cast<MaterializeTemporaryExpr>(Val: E)->getStorageDuration() == SD_Static;
2137 // A string literal has static storage duration.
2138 case Expr::StringLiteralClass:
2139 case Expr::PredefinedExprClass:
2140 case Expr::ObjCStringLiteralClass:
2141 case Expr::ObjCEncodeExprClass:
2142 return true;
2143 case Expr::ObjCBoxedExprClass:
2144 return cast<ObjCBoxedExpr>(Val: E)->isExpressibleAsConstantInitializer();
2145 case Expr::CallExprClass:
2146 return IsOpaqueConstantCall(E: cast<CallExpr>(Val: E));
2147 // For GCC compatibility, &&label has static storage duration.
2148 case Expr::AddrLabelExprClass:
2149 return true;
2150 // A Block literal expression may be used as the initialization value for
2151 // Block variables at global or local static scope.
2152 case Expr::BlockExprClass:
2153 return !cast<BlockExpr>(Val: E)->getBlockDecl()->hasCaptures();
2154 // The APValue generated from a __builtin_source_location will be emitted as a
2155 // literal.
2156 case Expr::SourceLocExprClass:
2157 return true;
2158 case Expr::ImplicitValueInitExprClass:
2159 // FIXME:
2160 // We can never form an lvalue with an implicit value initialization as its
2161 // base through expression evaluation, so these only appear in one case: the
2162 // implicit variable declaration we invent when checking whether a constexpr
2163 // constructor can produce a constant expression. We must assume that such
2164 // an expression might be a global lvalue.
2165 return true;
2166 }
2167}
2168
2169static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
2170 return LVal.Base.dyn_cast<const ValueDecl*>();
2171}
2172
2173// Information about an LValueBase that is some kind of string.
2174struct LValueBaseString {
2175 std::string ObjCEncodeStorage;
2176 StringRef Bytes;
2177 int CharWidth;
2178};
2179
2180// Gets the lvalue base of LVal as a string.
2181static bool GetLValueBaseAsString(const EvalInfo &Info, const LValue &LVal,
2182 LValueBaseString &AsString) {
2183 const auto *BaseExpr = LVal.Base.dyn_cast<const Expr *>();
2184 if (!BaseExpr)
2185 return false;
2186
2187 // For ObjCEncodeExpr, we need to compute and store the string.
2188 if (const auto *EE = dyn_cast<ObjCEncodeExpr>(Val: BaseExpr)) {
2189 Info.Ctx.getObjCEncodingForType(T: EE->getEncodedType(),
2190 S&: AsString.ObjCEncodeStorage);
2191 AsString.Bytes = AsString.ObjCEncodeStorage;
2192 AsString.CharWidth = 1;
2193 return true;
2194 }
2195
2196 // Otherwise, we have a StringLiteral.
2197 const auto *Lit = dyn_cast<StringLiteral>(Val: BaseExpr);
2198 if (const auto *PE = dyn_cast<PredefinedExpr>(Val: BaseExpr))
2199 Lit = PE->getFunctionName();
2200
2201 if (!Lit)
2202 return false;
2203
2204 AsString.Bytes = Lit->getBytes();
2205 AsString.CharWidth = Lit->getCharByteWidth();
2206 return true;
2207}
2208
2209// Determine whether two string literals potentially overlap. This will be the
2210// case if they agree on the values of all the bytes on the overlapping region
2211// between them.
2212//
2213// The overlapping region is the portion of the two string literals that must
2214// overlap in memory if the pointers actually point to the same address at
2215// runtime. For example, if LHS is "abcdef" + 3 and RHS is "cdef\0gh" + 1 then
2216// the overlapping region is "cdef\0", which in this case does agree, so the
2217// strings are potentially overlapping. Conversely, for "foobar" + 3 versus
2218// "bazbar" + 3, the overlapping region contains all of both strings, so they
2219// are not potentially overlapping, even though they agree from the given
2220// addresses onwards.
2221//
2222// See open core issue CWG2765 which is discussing the desired rule here.
2223static bool ArePotentiallyOverlappingStringLiterals(const EvalInfo &Info,
2224 const LValue &LHS,
2225 const LValue &RHS) {
2226 LValueBaseString LHSString, RHSString;
2227 if (!GetLValueBaseAsString(Info, LVal: LHS, AsString&: LHSString) ||
2228 !GetLValueBaseAsString(Info, LVal: RHS, AsString&: RHSString))
2229 return false;
2230
2231 // This is the byte offset to the location of the first character of LHS
2232 // within RHS. We don't need to look at the characters of one string that
2233 // would appear before the start of the other string if they were merged.
2234 CharUnits Offset = RHS.Offset - LHS.Offset;
2235 if (Offset.isNegative()) {
2236 if (LHSString.Bytes.size() < (size_t)-Offset.getQuantity())
2237 return false;
2238 LHSString.Bytes = LHSString.Bytes.drop_front(N: -Offset.getQuantity());
2239 } else {
2240 if (RHSString.Bytes.size() < (size_t)Offset.getQuantity())
2241 return false;
2242 RHSString.Bytes = RHSString.Bytes.drop_front(N: Offset.getQuantity());
2243 }
2244
2245 bool LHSIsLonger = LHSString.Bytes.size() > RHSString.Bytes.size();
2246 StringRef Longer = LHSIsLonger ? LHSString.Bytes : RHSString.Bytes;
2247 StringRef Shorter = LHSIsLonger ? RHSString.Bytes : LHSString.Bytes;
2248 int ShorterCharWidth = (LHSIsLonger ? RHSString : LHSString).CharWidth;
2249
2250 // The null terminator isn't included in the string data, so check for it
2251 // manually. If the longer string doesn't have a null terminator where the
2252 // shorter string ends, they aren't potentially overlapping.
2253 for (int NullByte : llvm::seq(Size: ShorterCharWidth)) {
2254 if (Shorter.size() + NullByte >= Longer.size())
2255 break;
2256 if (Longer[Shorter.size() + NullByte])
2257 return false;
2258 }
2259
2260 // Otherwise, they're potentially overlapping if and only if the overlapping
2261 // region is the same.
2262 return Shorter == Longer.take_front(N: Shorter.size());
2263}
2264
2265static bool IsWeakLValue(const LValue &Value) {
2266 const ValueDecl *Decl = GetLValueBaseDecl(LVal: Value);
2267 return Decl && Decl->isWeak();
2268}
2269
2270static bool isZeroSized(const LValue &Value) {
2271 const ValueDecl *Decl = GetLValueBaseDecl(LVal: Value);
2272 if (isa_and_nonnull<VarDecl>(Val: Decl)) {
2273 QualType Ty = Decl->getType();
2274 if (Ty->isArrayType())
2275 return Ty->isIncompleteType() ||
2276 Decl->getASTContext().getTypeSize(T: Ty) == 0;
2277 }
2278 return false;
2279}
2280
2281static bool HasSameBase(const LValue &A, const LValue &B) {
2282 if (!A.getLValueBase())
2283 return !B.getLValueBase();
2284 if (!B.getLValueBase())
2285 return false;
2286
2287 if (A.getLValueBase().getOpaqueValue() !=
2288 B.getLValueBase().getOpaqueValue())
2289 return false;
2290
2291 return A.getLValueCallIndex() == B.getLValueCallIndex() &&
2292 A.getLValueVersion() == B.getLValueVersion();
2293}
2294
2295static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
2296 assert(Base && "no location for a null lvalue");
2297 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2298
2299 // For a parameter, find the corresponding call stack frame (if it still
2300 // exists), and point at the parameter of the function definition we actually
2301 // invoked.
2302 if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(Val: VD)) {
2303 unsigned Idx = PVD->getFunctionScopeIndex();
2304 for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) {
2305 if (F->Arguments.CallIndex == Base.getCallIndex() &&
2306 F->Arguments.Version == Base.getVersion() && F->Callee &&
2307 Idx < F->Callee->getNumParams()) {
2308 VD = F->Callee->getParamDecl(i: Idx);
2309 break;
2310 }
2311 }
2312 }
2313
2314 if (VD)
2315 Info.Note(Loc: VD->getLocation(), DiagId: diag::note_declared_at);
2316 else if (const Expr *E = Base.dyn_cast<const Expr*>())
2317 Info.Note(Loc: E->getExprLoc(), DiagId: diag::note_constexpr_temporary_here);
2318 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
2319 // FIXME: Produce a note for dangling pointers too.
2320 if (std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA))
2321 Info.Note(Loc: (*Alloc)->AllocExpr->getExprLoc(),
2322 DiagId: diag::note_constexpr_dynamic_alloc_here);
2323 }
2324
2325 // We have no information to show for a typeid(T) object.
2326}
2327
2328enum class CheckEvaluationResultKind {
2329 ConstantExpression,
2330 FullyInitialized,
2331};
2332
2333/// Materialized temporaries that we've already checked to determine if they're
2334/// initializsed by a constant expression.
2335using CheckedTemporaries =
2336 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;
2337
2338static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2339 EvalInfo &Info, SourceLocation DiagLoc,
2340 QualType Type, const APValue &Value,
2341 ConstantExprKind Kind,
2342 const FieldDecl *SubobjectDecl,
2343 CheckedTemporaries &CheckedTemps);
2344
2345/// Check that this reference or pointer core constant expression is a valid
2346/// value for an address or reference constant expression. Return true if we
2347/// can fold this expression, whether or not it's a constant expression.
2348static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
2349 QualType Type, const LValue &LVal,
2350 ConstantExprKind Kind,
2351 CheckedTemporaries &CheckedTemps) {
2352 bool IsReferenceType = Type->isReferenceType();
2353
2354 APValue::LValueBase Base = LVal.getLValueBase();
2355 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
2356
2357 const Expr *BaseE = Base.dyn_cast<const Expr *>();
2358 const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>();
2359
2360 // Additional restrictions apply in a template argument. We only enforce the
2361 // C++20 restrictions here; additional syntactic and semantic restrictions
2362 // are applied elsewhere.
2363 if (isTemplateArgument(Kind)) {
2364 int InvalidBaseKind = -1;
2365 StringRef Ident;
2366 if (Base.is<TypeInfoLValue>())
2367 InvalidBaseKind = 0;
2368 else if (isa_and_nonnull<StringLiteral>(Val: BaseE))
2369 InvalidBaseKind = 1;
2370 else if (isa_and_nonnull<MaterializeTemporaryExpr>(Val: BaseE) ||
2371 isa_and_nonnull<LifetimeExtendedTemporaryDecl>(Val: BaseVD))
2372 InvalidBaseKind = 2;
2373 else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(Val: BaseE)) {
2374 InvalidBaseKind = 3;
2375 Ident = PE->getIdentKindName();
2376 }
2377
2378 if (InvalidBaseKind != -1) {
2379 Info.FFDiag(Loc, DiagId: diag::note_constexpr_invalid_template_arg)
2380 << IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind
2381 << Ident;
2382 return false;
2383 }
2384 }
2385
2386 if (auto *FD = dyn_cast_or_null<FunctionDecl>(Val: BaseVD);
2387 FD && FD->isImmediateFunction()) {
2388 Info.FFDiag(Loc, DiagId: diag::note_consteval_address_accessible)
2389 << !Type->isAnyPointerType();
2390 Info.Note(Loc: FD->getLocation(), DiagId: diag::note_declared_at);
2391 return false;
2392 }
2393
2394 // Check that the object is a global. Note that the fake 'this' object we
2395 // manufacture when checking potential constant expressions is conservatively
2396 // assumed to be global here.
2397 if (!IsGlobalLValue(B: Base)) {
2398 if (Info.getLangOpts().CPlusPlus11) {
2399 Info.FFDiag(Loc, DiagId: diag::note_constexpr_non_global, ExtraNotes: 1)
2400 << IsReferenceType << !Designator.Entries.empty() << !!BaseVD
2401 << BaseVD;
2402 auto *VarD = dyn_cast_or_null<VarDecl>(Val: BaseVD);
2403 if (VarD && VarD->isConstexpr()) {
2404 // Non-static local constexpr variables have unintuitive semantics:
2405 // constexpr int a = 1;
2406 // constexpr const int *p = &a;
2407 // ... is invalid because the address of 'a' is not constant. Suggest
2408 // adding a 'static' in this case.
2409 Info.Note(Loc: VarD->getLocation(), DiagId: diag::note_constexpr_not_static)
2410 << VarD
2411 << FixItHint::CreateInsertion(InsertionLoc: VarD->getBeginLoc(), Code: "static ");
2412 } else {
2413 NoteLValueLocation(Info, Base);
2414 }
2415 } else {
2416 Info.FFDiag(Loc);
2417 }
2418 // Don't allow references to temporaries to escape.
2419 return false;
2420 }
2421 assert((Info.checkingPotentialConstantExpression() ||
2422 LVal.getLValueCallIndex() == 0) &&
2423 "have call index for global lvalue");
2424
2425 if (LVal.allowConstexprUnknown()) {
2426 if (BaseVD) {
2427 Info.FFDiag(Loc, DiagId: diag::note_constexpr_var_init_non_constant, ExtraNotes: 1) << BaseVD;
2428 NoteLValueLocation(Info, Base);
2429 } else {
2430 Info.FFDiag(Loc);
2431 }
2432 return false;
2433 }
2434
2435 if (Base.is<DynamicAllocLValue>()) {
2436 Info.FFDiag(Loc, DiagId: diag::note_constexpr_dynamic_alloc)
2437 << IsReferenceType << !Designator.Entries.empty();
2438 NoteLValueLocation(Info, Base);
2439 return false;
2440 }
2441
2442 if (BaseVD) {
2443 if (const VarDecl *Var = dyn_cast<const VarDecl>(Val: BaseVD)) {
2444 // Check if this is a thread-local variable.
2445 if (Var->getTLSKind())
2446 // FIXME: Diagnostic!
2447 return false;
2448
2449 // A dllimport variable never acts like a constant, unless we're
2450 // evaluating a value for use only in name mangling.
2451 if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>())
2452 // FIXME: Diagnostic!
2453 return false;
2454
2455 // In CUDA/HIP device compilation, only device side variables have
2456 // constant addresses.
2457 if (Info.getASTContext().getLangOpts().CUDA &&
2458 Info.getASTContext().getLangOpts().CUDAIsDevice &&
2459 Info.getASTContext().CUDAConstantEvalCtx.NoWrongSidedVars) {
2460 if ((!Var->hasAttr<CUDADeviceAttr>() &&
2461 !Var->hasAttr<CUDAConstantAttr>() &&
2462 !Var->getType()->isCUDADeviceBuiltinSurfaceType() &&
2463 !Var->getType()->isCUDADeviceBuiltinTextureType()) ||
2464 Var->hasAttr<HIPManagedAttr>())
2465 return false;
2466 }
2467 }
2468 if (const auto *FD = dyn_cast<const FunctionDecl>(Val: BaseVD)) {
2469 // __declspec(dllimport) must be handled very carefully:
2470 // We must never initialize an expression with the thunk in C++.
2471 // Doing otherwise would allow the same id-expression to yield
2472 // different addresses for the same function in different translation
2473 // units. However, this means that we must dynamically initialize the
2474 // expression with the contents of the import address table at runtime.
2475 //
2476 // The C language has no notion of ODR; furthermore, it has no notion of
2477 // dynamic initialization. This means that we are permitted to
2478 // perform initialization with the address of the thunk.
2479 if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) &&
2480 FD->hasAttr<DLLImportAttr>())
2481 // FIXME: Diagnostic!
2482 return false;
2483 }
2484 } else if (const auto *MTE =
2485 dyn_cast_or_null<MaterializeTemporaryExpr>(Val: BaseE)) {
2486 if (CheckedTemps.insert(Ptr: MTE).second) {
2487 QualType TempType = getType(B: Base);
2488 if (TempType.isDestructedType()) {
2489 Info.FFDiag(Loc: MTE->getExprLoc(),
2490 DiagId: diag::note_constexpr_unsupported_temporary_nontrivial_dtor)
2491 << TempType;
2492 return false;
2493 }
2494
2495 APValue *V = MTE->getOrCreateValue(MayCreate: false);
2496 assert(V && "evasluation result refers to uninitialised temporary");
2497 if (!CheckEvaluationResult(CERK: CheckEvaluationResultKind::ConstantExpression,
2498 Info, DiagLoc: MTE->getExprLoc(), Type: TempType, Value: *V, Kind,
2499 /*SubobjectDecl=*/nullptr, CheckedTemps))
2500 return false;
2501 }
2502 }
2503
2504 // Allow address constant expressions to be past-the-end pointers. This is
2505 // an extension: the standard requires them to point to an object.
2506 if (!IsReferenceType)
2507 return true;
2508
2509 // A reference constant expression must refer to an object.
2510 if (!Base) {
2511 // FIXME: diagnostic
2512 Info.CCEDiag(Loc);
2513 return true;
2514 }
2515
2516 // Does this refer one past the end of some object?
2517 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
2518 Info.FFDiag(Loc, DiagId: diag::note_constexpr_past_end, ExtraNotes: 1)
2519 << !Designator.Entries.empty() << !!BaseVD << BaseVD;
2520 NoteLValueLocation(Info, Base);
2521 }
2522
2523 return true;
2524}
2525
2526/// Member pointers are constant expressions unless they point to a
2527/// non-virtual dllimport member function.
2528static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
2529 SourceLocation Loc,
2530 QualType Type,
2531 const APValue &Value,
2532 ConstantExprKind Kind) {
2533 const ValueDecl *Member = Value.getMemberPointerDecl();
2534 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Val: Member);
2535 if (!FD)
2536 return true;
2537 if (FD->isImmediateFunction()) {
2538 Info.FFDiag(Loc, DiagId: diag::note_consteval_address_accessible) << /*pointer*/ 0;
2539 Info.Note(Loc: FD->getLocation(), DiagId: diag::note_declared_at);
2540 return false;
2541 }
2542 return isForManglingOnly(Kind) || FD->isVirtual() ||
2543 !FD->hasAttr<DLLImportAttr>();
2544}
2545
2546/// Check that this core constant expression is of literal type, and if not,
2547/// produce an appropriate diagnostic.
2548static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
2549 const LValue *This = nullptr) {
2550 // The restriction to literal types does not exist in C++23 anymore.
2551 if (Info.getLangOpts().CPlusPlus23)
2552 return true;
2553
2554 if (!E->isPRValue() || E->getType()->isLiteralType(Ctx: Info.Ctx))
2555 return true;
2556
2557 // C++1y: A constant initializer for an object o [...] may also invoke
2558 // constexpr constructors for o and its subobjects even if those objects
2559 // are of non-literal class types.
2560 //
2561 // C++11 missed this detail for aggregates, so classes like this:
2562 // struct foo_t { union { int i; volatile int j; } u; };
2563 // are not (obviously) initializable like so:
2564 // __attribute__((__require_constant_initialization__))
2565 // static const foo_t x = {{0}};
2566 // because "i" is a subobject with non-literal initialization (due to the
2567 // volatile member of the union). See:
2568 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
2569 // Therefore, we use the C++1y behavior.
2570 if (This && Info.EvaluatingDecl == This->getLValueBase())
2571 return true;
2572
2573 // Prvalue constant expressions must be of literal types.
2574 if (Info.getLangOpts().CPlusPlus11)
2575 Info.FFDiag(E, DiagId: diag::note_constexpr_nonliteral)
2576 << E->getType();
2577 else
2578 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
2579 return false;
2580}
2581
2582static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2583 EvalInfo &Info, SourceLocation DiagLoc,
2584 QualType Type, const APValue &Value,
2585 ConstantExprKind Kind,
2586 const FieldDecl *SubobjectDecl,
2587 CheckedTemporaries &CheckedTemps) {
2588 if (!Value.hasValue()) {
2589 if (SubobjectDecl) {
2590 Info.FFDiag(Loc: DiagLoc, DiagId: diag::note_constexpr_uninitialized)
2591 << /*(name)*/ 1 << SubobjectDecl;
2592 Info.Note(Loc: SubobjectDecl->getLocation(),
2593 DiagId: diag::note_constexpr_subobject_declared_here);
2594 } else {
2595 Info.FFDiag(Loc: DiagLoc, DiagId: diag::note_constexpr_uninitialized)
2596 << /*of type*/ 0 << Type;
2597 }
2598 return false;
2599 }
2600
2601 // We allow _Atomic(T) to be initialized from anything that T can be
2602 // initialized from.
2603 if (const AtomicType *AT = Type->getAs<AtomicType>())
2604 Type = AT->getValueType();
2605
2606 // Core issue 1454: For a literal constant expression of array or class type,
2607 // each subobject of its value shall have been initialized by a constant
2608 // expression.
2609 if (Value.isArray()) {
2610 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
2611 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
2612 if (!CheckEvaluationResult(CERK, Info, DiagLoc, Type: EltTy,
2613 Value: Value.getArrayInitializedElt(I), Kind,
2614 SubobjectDecl, CheckedTemps))
2615 return false;
2616 }
2617 if (!Value.hasArrayFiller())
2618 return true;
2619 return CheckEvaluationResult(CERK, Info, DiagLoc, Type: EltTy,
2620 Value: Value.getArrayFiller(), Kind, SubobjectDecl,
2621 CheckedTemps);
2622 }
2623 if (Value.isUnion() && Value.getUnionField()) {
2624 return CheckEvaluationResult(
2625 CERK, Info, DiagLoc, Type: Value.getUnionField()->getType(),
2626 Value: Value.getUnionValue(), Kind, SubobjectDecl: Value.getUnionField(), CheckedTemps);
2627 }
2628 if (Value.isStruct()) {
2629 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
2630 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(Val: RD)) {
2631 unsigned BaseIndex = 0;
2632 for (const CXXBaseSpecifier &BS : CD->bases()) {
2633 const APValue &BaseValue = Value.getStructBase(i: BaseIndex);
2634 if (!BaseValue.hasValue()) {
2635 SourceLocation TypeBeginLoc = BS.getBaseTypeLoc();
2636 Info.FFDiag(Loc: TypeBeginLoc, DiagId: diag::note_constexpr_uninitialized_base)
2637 << BS.getType() << SourceRange(TypeBeginLoc, BS.getEndLoc());
2638 return false;
2639 }
2640 if (!CheckEvaluationResult(CERK, Info, DiagLoc, Type: BS.getType(), Value: BaseValue,
2641 Kind, /*SubobjectDecl=*/nullptr,
2642 CheckedTemps))
2643 return false;
2644 ++BaseIndex;
2645 }
2646 }
2647 for (const auto *I : RD->fields()) {
2648 if (I->isUnnamedBitField())
2649 continue;
2650
2651 if (!CheckEvaluationResult(CERK, Info, DiagLoc, Type: I->getType(),
2652 Value: Value.getStructField(i: I->getFieldIndex()), Kind,
2653 SubobjectDecl: I, CheckedTemps))
2654 return false;
2655 }
2656 }
2657
2658 if (Value.isLValue() &&
2659 CERK == CheckEvaluationResultKind::ConstantExpression) {
2660 LValue LVal;
2661 LVal.setFrom(Ctx&: Info.Ctx, V: Value);
2662 return CheckLValueConstantExpression(Info, Loc: DiagLoc, Type, LVal, Kind,
2663 CheckedTemps);
2664 }
2665
2666 if (Value.isMemberPointer() &&
2667 CERK == CheckEvaluationResultKind::ConstantExpression)
2668 return CheckMemberPointerConstantExpression(Info, Loc: DiagLoc, Type, Value, Kind);
2669
2670 // Everything else is fine.
2671 return true;
2672}
2673
2674/// Check that this core constant expression value is a valid value for a
2675/// constant expression. If not, report an appropriate diagnostic. Does not
2676/// check that the expression is of literal type.
2677static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
2678 QualType Type, const APValue &Value,
2679 ConstantExprKind Kind) {
2680 // Nothing to check for a constant expression of type 'cv void'.
2681 if (Type->isVoidType())
2682 return true;
2683
2684 CheckedTemporaries CheckedTemps;
2685 return CheckEvaluationResult(CERK: CheckEvaluationResultKind::ConstantExpression,
2686 Info, DiagLoc, Type, Value, Kind,
2687 /*SubobjectDecl=*/nullptr, CheckedTemps);
2688}
2689
2690/// Check that this evaluated value is fully-initialized and can be loaded by
2691/// an lvalue-to-rvalue conversion.
2692static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
2693 QualType Type, const APValue &Value) {
2694 CheckedTemporaries CheckedTemps;
2695 return CheckEvaluationResult(
2696 CERK: CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
2697 Kind: ConstantExprKind::Normal, /*SubobjectDecl=*/nullptr, CheckedTemps);
2698}
2699
2700/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2701/// "the allocated storage is deallocated within the evaluation".
2702static bool CheckMemoryLeaks(EvalInfo &Info) {
2703 if (!Info.HeapAllocs.empty()) {
2704 // We can still fold to a constant despite a compile-time memory leak,
2705 // so long as the heap allocation isn't referenced in the result (we check
2706 // that in CheckConstantExpression).
2707 Info.CCEDiag(E: Info.HeapAllocs.begin()->second.AllocExpr,
2708 DiagId: diag::note_constexpr_memory_leak)
2709 << unsigned(Info.HeapAllocs.size() - 1);
2710 }
2711 return true;
2712}
2713
2714static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
2715 // A null base expression indicates a null pointer. These are always
2716 // evaluatable, and they are false unless the offset is zero.
2717 if (!Value.getLValueBase()) {
2718 // TODO: Should a non-null pointer with an offset of zero evaluate to true?
2719 Result = !Value.getLValueOffset().isZero();
2720 return true;
2721 }
2722
2723 // We have a non-null base. These are generally known to be true, but if it's
2724 // a weak declaration it can be null at runtime.
2725 Result = true;
2726 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
2727 return !Decl || !Decl->isWeak();
2728}
2729
2730static bool HandleConversionToBool(const APValue &Val, bool &Result) {
2731 // TODO: This function should produce notes if it fails.
2732 switch (Val.getKind()) {
2733 case APValue::None:
2734 case APValue::Indeterminate:
2735 return false;
2736 case APValue::Int:
2737 Result = Val.getInt().getBoolValue();
2738 return true;
2739 case APValue::FixedPoint:
2740 Result = Val.getFixedPoint().getBoolValue();
2741 return true;
2742 case APValue::Float:
2743 Result = !Val.getFloat().isZero();
2744 return true;
2745 case APValue::ComplexInt:
2746 Result = Val.getComplexIntReal().getBoolValue() ||
2747 Val.getComplexIntImag().getBoolValue();
2748 return true;
2749 case APValue::ComplexFloat:
2750 Result = !Val.getComplexFloatReal().isZero() ||
2751 !Val.getComplexFloatImag().isZero();
2752 return true;
2753 case APValue::LValue:
2754 return EvalPointerValueAsBool(Value: Val, Result);
2755 case APValue::MemberPointer:
2756 if (Val.getMemberPointerDecl() && Val.getMemberPointerDecl()->isWeak()) {
2757 return false;
2758 }
2759 Result = Val.getMemberPointerDecl();
2760 return true;
2761 case APValue::Vector:
2762 case APValue::Array:
2763 case APValue::Struct:
2764 case APValue::Union:
2765 case APValue::AddrLabelDiff:
2766 return false;
2767 }
2768
2769 llvm_unreachable("unknown APValue kind");
2770}
2771
2772static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
2773 EvalInfo &Info) {
2774 assert(!E->isValueDependent());
2775 assert(E->isPRValue() && "missing lvalue-to-rvalue conv in bool condition");
2776 APValue Val;
2777 if (!Evaluate(Result&: Val, Info, E))
2778 return false;
2779 return HandleConversionToBool(Val, Result);
2780}
2781
2782template<typename T>
2783static bool HandleOverflow(EvalInfo &Info, const Expr *E,
2784 const T &SrcValue, QualType DestType) {
2785 Info.CCEDiag(E, DiagId: diag::note_constexpr_overflow)
2786 << SrcValue << DestType;
2787 return Info.noteUndefinedBehavior();
2788}
2789
2790static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
2791 QualType SrcType, const APFloat &Value,
2792 QualType DestType, APSInt &Result) {
2793 unsigned DestWidth = Info.Ctx.getIntWidth(T: DestType);
2794 // Determine whether we are converting to unsigned or signed.
2795 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
2796
2797 Result = APSInt(DestWidth, !DestSigned);
2798 bool ignored;
2799 if (Value.convertToInteger(Result, RM: llvm::APFloat::rmTowardZero, IsExact: &ignored)
2800 & APFloat::opInvalidOp)
2801 return HandleOverflow(Info, E, SrcValue: Value, DestType);
2802 return true;
2803}
2804
2805/// Get rounding mode to use in evaluation of the specified expression.
2806///
2807/// If rounding mode is unknown at compile time, still try to evaluate the
2808/// expression. If the result is exact, it does not depend on rounding mode.
2809/// So return "tonearest" mode instead of "dynamic".
2810static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E) {
2811 llvm::RoundingMode RM =
2812 E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts()).getRoundingMode();
2813 if (RM == llvm::RoundingMode::Dynamic)
2814 RM = llvm::RoundingMode::NearestTiesToEven;
2815 return RM;
2816}
2817
2818/// Check if the given evaluation result is allowed for constant evaluation.
2819static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E,
2820 APFloat::opStatus St) {
2821 // In a constant context, assume that any dynamic rounding mode or FP
2822 // exception state matches the default floating-point environment.
2823 if (Info.InConstantContext)
2824 return true;
2825
2826 FPOptions FPO = E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts());
2827 if ((St & APFloat::opInexact) &&
2828 FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) {
2829 // Inexact result means that it depends on rounding mode. If the requested
2830 // mode is dynamic, the evaluation cannot be made in compile time.
2831 Info.FFDiag(E, DiagId: diag::note_constexpr_dynamic_rounding);
2832 return false;
2833 }
2834
2835 if ((St != APFloat::opOK) &&
2836 (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic ||
2837 FPO.getExceptionMode() != LangOptions::FPE_Ignore ||
2838 FPO.getAllowFEnvAccess())) {
2839 Info.FFDiag(E, DiagId: diag::note_constexpr_float_arithmetic_strict);
2840 return false;
2841 }
2842
2843 if ((St & APFloat::opStatus::opInvalidOp) &&
2844 FPO.getExceptionMode() != LangOptions::FPE_Ignore) {
2845 // There is no usefully definable result.
2846 Info.FFDiag(E);
2847 return false;
2848 }
2849
2850 // FIXME: if:
2851 // - evaluation triggered other FP exception, and
2852 // - exception mode is not "ignore", and
2853 // - the expression being evaluated is not a part of global variable
2854 // initializer,
2855 // the evaluation probably need to be rejected.
2856 return true;
2857}
2858
2859static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
2860 QualType SrcType, QualType DestType,
2861 APFloat &Result) {
2862 assert((isa<CastExpr>(E) || isa<CompoundAssignOperator>(E) ||
2863 isa<ConvertVectorExpr>(E)) &&
2864 "HandleFloatToFloatCast has been checked with only CastExpr, "
2865 "CompoundAssignOperator and ConvertVectorExpr. Please either validate "
2866 "the new expression or address the root cause of this usage.");
2867 llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
2868 APFloat::opStatus St;
2869 APFloat Value = Result;
2870 bool ignored;
2871 St = Result.convert(ToSemantics: Info.Ctx.getFloatTypeSemantics(T: DestType), RM, losesInfo: &ignored);
2872 return checkFloatingPointResult(Info, E, St);
2873}
2874
2875static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
2876 QualType DestType, QualType SrcType,
2877 const APSInt &Value) {
2878 unsigned DestWidth = Info.Ctx.getIntWidth(T: DestType);
2879 // Figure out if this is a truncate, extend or noop cast.
2880 // If the input is signed, do a sign extend, noop, or truncate.
2881 APSInt Result = Value.extOrTrunc(width: DestWidth);
2882 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
2883 if (DestType->isBooleanType())
2884 Result = Value.getBoolValue();
2885 return Result;
2886}
2887
2888static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
2889 const FPOptions FPO,
2890 QualType SrcType, const APSInt &Value,
2891 QualType DestType, APFloat &Result) {
2892 Result = APFloat(Info.Ctx.getFloatTypeSemantics(T: DestType), 1);
2893 llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
2894 APFloat::opStatus St = Result.convertFromAPInt(Input: Value, IsSigned: Value.isSigned(), RM);
2895 return checkFloatingPointResult(Info, E, St);
2896}
2897
2898static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
2899 APValue &Value, const FieldDecl *FD) {
2900 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
2901
2902 if (!Value.isInt()) {
2903 // Trying to store a pointer-cast-to-integer into a bitfield.
2904 // FIXME: In this case, we should provide the diagnostic for casting
2905 // a pointer to an integer.
2906 assert(Value.isLValue() && "integral value neither int nor lvalue?");
2907 Info.FFDiag(E);
2908 return false;
2909 }
2910
2911 APSInt &Int = Value.getInt();
2912 unsigned OldBitWidth = Int.getBitWidth();
2913 unsigned NewBitWidth = FD->getBitWidthValue();
2914 if (NewBitWidth < OldBitWidth)
2915 Int = Int.trunc(width: NewBitWidth).extend(width: OldBitWidth);
2916 return true;
2917}
2918
2919/// Perform the given integer operation, which is known to need at most BitWidth
2920/// bits, and check for overflow in the original type (if that type was not an
2921/// unsigned type).
2922template<typename Operation>
2923static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
2924 const APSInt &LHS, const APSInt &RHS,
2925 unsigned BitWidth, Operation Op,
2926 APSInt &Result) {
2927 if (LHS.isUnsigned()) {
2928 Result = Op(LHS, RHS);
2929 return true;
2930 }
2931
2932 APSInt Value(Op(LHS.extend(width: BitWidth), RHS.extend(width: BitWidth)), false);
2933 Result = Value.trunc(width: LHS.getBitWidth());
2934 if (Result.extend(width: BitWidth) != Value) {
2935 if (Info.checkingForUndefinedBehavior())
2936 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
2937 DiagID: diag::warn_integer_constant_overflow)
2938 << toString(I: Result, Radix: 10, Signed: Result.isSigned(), /*formatAsCLiteral=*/false,
2939 /*UpperCase=*/true, /*InsertSeparators=*/true)
2940 << E->getType() << E->getSourceRange();
2941 return HandleOverflow(Info, E, SrcValue: Value, DestType: E->getType());
2942 }
2943 return true;
2944}
2945
2946/// Perform the given binary integer operation.
2947static bool handleIntIntBinOp(EvalInfo &Info, const BinaryOperator *E,
2948 const APSInt &LHS, BinaryOperatorKind Opcode,
2949 APSInt RHS, APSInt &Result) {
2950 bool HandleOverflowResult = true;
2951 switch (Opcode) {
2952 default:
2953 Info.FFDiag(E);
2954 return false;
2955 case BO_Mul:
2956 return CheckedIntArithmetic(Info, E, LHS, RHS, BitWidth: LHS.getBitWidth() * 2,
2957 Op: std::multiplies<APSInt>(), Result);
2958 case BO_Add:
2959 return CheckedIntArithmetic(Info, E, LHS, RHS, BitWidth: LHS.getBitWidth() + 1,
2960 Op: std::plus<APSInt>(), Result);
2961 case BO_Sub:
2962 return CheckedIntArithmetic(Info, E, LHS, RHS, BitWidth: LHS.getBitWidth() + 1,
2963 Op: std::minus<APSInt>(), Result);
2964 case BO_And: Result = LHS & RHS; return true;
2965 case BO_Xor: Result = LHS ^ RHS; return true;
2966 case BO_Or: Result = LHS | RHS; return true;
2967 case BO_Div:
2968 case BO_Rem:
2969 if (RHS == 0) {
2970 Info.FFDiag(E, DiagId: diag::note_expr_divide_by_zero)
2971 << E->getRHS()->getSourceRange();
2972 return false;
2973 }
2974 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2975 // this operation and gives the two's complement result.
2976 if (RHS.isNegative() && RHS.isAllOnes() && LHS.isSigned() &&
2977 LHS.isMinSignedValue())
2978 HandleOverflowResult = HandleOverflow(
2979 Info, E, SrcValue: -LHS.extend(width: LHS.getBitWidth() + 1), DestType: E->getType());
2980 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2981 return HandleOverflowResult;
2982 case BO_Shl: {
2983 if (Info.getLangOpts().OpenCL)
2984 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2985 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2986 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2987 RHS.isUnsigned());
2988 else if (RHS.isSigned() && RHS.isNegative()) {
2989 // During constant-folding, a negative shift is an opposite shift. Such
2990 // a shift is not a constant expression.
2991 Info.CCEDiag(E, DiagId: diag::note_constexpr_negative_shift) << RHS;
2992 if (!Info.noteUndefinedBehavior())
2993 return false;
2994 RHS = -RHS;
2995 goto shift_right;
2996 }
2997 shift_left:
2998 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2999 // the shifted type.
3000 unsigned SA = (unsigned) RHS.getLimitedValue(Limit: LHS.getBitWidth()-1);
3001 if (SA != RHS) {
3002 Info.CCEDiag(E, DiagId: diag::note_constexpr_large_shift)
3003 << RHS << E->getType() << LHS.getBitWidth();
3004 if (!Info.noteUndefinedBehavior())
3005 return false;
3006 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
3007 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
3008 // operand, and must not overflow the corresponding unsigned type.
3009 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
3010 // E1 x 2^E2 module 2^N.
3011 if (LHS.isNegative()) {
3012 Info.CCEDiag(E, DiagId: diag::note_constexpr_lshift_of_negative) << LHS;
3013 if (!Info.noteUndefinedBehavior())
3014 return false;
3015 } else if (LHS.countl_zero() < SA) {
3016 Info.CCEDiag(E, DiagId: diag::note_constexpr_lshift_discards);
3017 if (!Info.noteUndefinedBehavior())
3018 return false;
3019 }
3020 }
3021 Result = LHS << SA;
3022 return true;
3023 }
3024 case BO_Shr: {
3025 if (Info.getLangOpts().OpenCL)
3026 // OpenCL 6.3j: shift values are effectively % word size of LHS.
3027 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
3028 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
3029 RHS.isUnsigned());
3030 else if (RHS.isSigned() && RHS.isNegative()) {
3031 // During constant-folding, a negative shift is an opposite shift. Such a
3032 // shift is not a constant expression.
3033 Info.CCEDiag(E, DiagId: diag::note_constexpr_negative_shift) << RHS;
3034 if (!Info.noteUndefinedBehavior())
3035 return false;
3036 RHS = -RHS;
3037 goto shift_left;
3038 }
3039 shift_right:
3040 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
3041 // shifted type.
3042 unsigned SA = (unsigned) RHS.getLimitedValue(Limit: LHS.getBitWidth()-1);
3043 if (SA != RHS) {
3044 Info.CCEDiag(E, DiagId: diag::note_constexpr_large_shift)
3045 << RHS << E->getType() << LHS.getBitWidth();
3046 if (!Info.noteUndefinedBehavior())
3047 return false;
3048 }
3049
3050 Result = LHS >> SA;
3051 return true;
3052 }
3053
3054 case BO_LT: Result = LHS < RHS; return true;
3055 case BO_GT: Result = LHS > RHS; return true;
3056 case BO_LE: Result = LHS <= RHS; return true;
3057 case BO_GE: Result = LHS >= RHS; return true;
3058 case BO_EQ: Result = LHS == RHS; return true;
3059 case BO_NE: Result = LHS != RHS; return true;
3060 case BO_Cmp:
3061 llvm_unreachable("BO_Cmp should be handled elsewhere");
3062 }
3063}
3064
3065/// Perform the given binary floating-point operation, in-place, on LHS.
3066static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E,
3067 APFloat &LHS, BinaryOperatorKind Opcode,
3068 const APFloat &RHS) {
3069 llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
3070 APFloat::opStatus St;
3071 switch (Opcode) {
3072 default:
3073 Info.FFDiag(E);
3074 return false;
3075 case BO_Mul:
3076 St = LHS.multiply(RHS, RM);
3077 break;
3078 case BO_Add:
3079 St = LHS.add(RHS, RM);
3080 break;
3081 case BO_Sub:
3082 St = LHS.subtract(RHS, RM);
3083 break;
3084 case BO_Div:
3085 // [expr.mul]p4:
3086 // If the second operand of / or % is zero the behavior is undefined.
3087 if (RHS.isZero())
3088 Info.CCEDiag(E, DiagId: diag::note_expr_divide_by_zero);
3089 St = LHS.divide(RHS, RM);
3090 break;
3091 }
3092
3093 // [expr.pre]p4:
3094 // If during the evaluation of an expression, the result is not
3095 // mathematically defined [...], the behavior is undefined.
3096 // FIXME: C++ rules require us to not conform to IEEE 754 here.
3097 if (LHS.isNaN()) {
3098 Info.CCEDiag(E, DiagId: diag::note_constexpr_float_arithmetic) << LHS.isNaN();
3099 return Info.noteUndefinedBehavior();
3100 }
3101
3102 return checkFloatingPointResult(Info, E, St);
3103}
3104
3105static bool handleLogicalOpForVector(const APInt &LHSValue,
3106 BinaryOperatorKind Opcode,
3107 const APInt &RHSValue, APInt &Result) {
3108 bool LHS = (LHSValue != 0);
3109 bool RHS = (RHSValue != 0);
3110
3111 if (Opcode == BO_LAnd)
3112 Result = LHS && RHS;
3113 else
3114 Result = LHS || RHS;
3115 return true;
3116}
3117static bool handleLogicalOpForVector(const APFloat &LHSValue,
3118 BinaryOperatorKind Opcode,
3119 const APFloat &RHSValue, APInt &Result) {
3120 bool LHS = !LHSValue.isZero();
3121 bool RHS = !RHSValue.isZero();
3122
3123 if (Opcode == BO_LAnd)
3124 Result = LHS && RHS;
3125 else
3126 Result = LHS || RHS;
3127 return true;
3128}
3129
3130static bool handleLogicalOpForVector(const APValue &LHSValue,
3131 BinaryOperatorKind Opcode,
3132 const APValue &RHSValue, APInt &Result) {
3133 // The result is always an int type, however operands match the first.
3134 if (LHSValue.getKind() == APValue::Int)
3135 return handleLogicalOpForVector(LHSValue: LHSValue.getInt(), Opcode,
3136 RHSValue: RHSValue.getInt(), Result);
3137 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
3138 return handleLogicalOpForVector(LHSValue: LHSValue.getFloat(), Opcode,
3139 RHSValue: RHSValue.getFloat(), Result);
3140}
3141
3142template <typename APTy>
3143static bool
3144handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
3145 const APTy &RHSValue, APInt &Result) {
3146 switch (Opcode) {
3147 default:
3148 llvm_unreachable("unsupported binary operator");
3149 case BO_EQ:
3150 Result = (LHSValue == RHSValue);
3151 break;
3152 case BO_NE:
3153 Result = (LHSValue != RHSValue);
3154 break;
3155 case BO_LT:
3156 Result = (LHSValue < RHSValue);
3157 break;
3158 case BO_GT:
3159 Result = (LHSValue > RHSValue);
3160 break;
3161 case BO_LE:
3162 Result = (LHSValue <= RHSValue);
3163 break;
3164 case BO_GE:
3165 Result = (LHSValue >= RHSValue);
3166 break;
3167 }
3168
3169 // The boolean operations on these vector types use an instruction that
3170 // results in a mask of '-1' for the 'truth' value. Ensure that we negate 1
3171 // to -1 to make sure that we produce the correct value.
3172 Result.negate();
3173
3174 return true;
3175}
3176
3177static bool handleCompareOpForVector(const APValue &LHSValue,
3178 BinaryOperatorKind Opcode,
3179 const APValue &RHSValue, APInt &Result) {
3180 // The result is always an int type, however operands match the first.
3181 if (LHSValue.getKind() == APValue::Int)
3182 return handleCompareOpForVectorHelper(LHSValue: LHSValue.getInt(), Opcode,
3183 RHSValue: RHSValue.getInt(), Result);
3184 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
3185 return handleCompareOpForVectorHelper(LHSValue: LHSValue.getFloat(), Opcode,
3186 RHSValue: RHSValue.getFloat(), Result);
3187}
3188
3189// Perform binary operations for vector types, in place on the LHS.
3190static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E,
3191 BinaryOperatorKind Opcode,
3192 APValue &LHSValue,
3193 const APValue &RHSValue) {
3194 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&
3195 "Operation not supported on vector types");
3196
3197 const auto *VT = E->getType()->castAs<VectorType>();
3198 unsigned NumElements = VT->getNumElements();
3199 QualType EltTy = VT->getElementType();
3200
3201 // In the cases (typically C as I've observed) where we aren't evaluating
3202 // constexpr but are checking for cases where the LHS isn't yet evaluatable,
3203 // just give up.
3204 if (!LHSValue.isVector()) {
3205 assert(LHSValue.isLValue() &&
3206 "A vector result that isn't a vector OR uncalculated LValue");
3207 Info.FFDiag(E);
3208 return false;
3209 }
3210
3211 assert(LHSValue.getVectorLength() == NumElements &&
3212 RHSValue.getVectorLength() == NumElements && "Different vector sizes");
3213
3214 SmallVector<APValue, 4> ResultElements;
3215
3216 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
3217 APValue LHSElt = LHSValue.getVectorElt(I: EltNum);
3218 APValue RHSElt = RHSValue.getVectorElt(I: EltNum);
3219
3220 if (EltTy->isIntegerType()) {
3221 APSInt EltResult{Info.Ctx.getIntWidth(T: EltTy),
3222 EltTy->isUnsignedIntegerType()};
3223 bool Success = true;
3224
3225 if (BinaryOperator::isLogicalOp(Opc: Opcode))
3226 Success = handleLogicalOpForVector(LHSValue: LHSElt, Opcode, RHSValue: RHSElt, Result&: EltResult);
3227 else if (BinaryOperator::isComparisonOp(Opc: Opcode))
3228 Success = handleCompareOpForVector(LHSValue: LHSElt, Opcode, RHSValue: RHSElt, Result&: EltResult);
3229 else
3230 Success = handleIntIntBinOp(Info, E, LHS: LHSElt.getInt(), Opcode,
3231 RHS: RHSElt.getInt(), Result&: EltResult);
3232
3233 if (!Success) {
3234 Info.FFDiag(E);
3235 return false;
3236 }
3237 ResultElements.emplace_back(Args&: EltResult);
3238
3239 } else if (EltTy->isFloatingType()) {
3240 assert(LHSElt.getKind() == APValue::Float &&
3241 RHSElt.getKind() == APValue::Float &&
3242 "Mismatched LHS/RHS/Result Type");
3243 APFloat LHSFloat = LHSElt.getFloat();
3244
3245 if (!handleFloatFloatBinOp(Info, E, LHS&: LHSFloat, Opcode,
3246 RHS: RHSElt.getFloat())) {
3247 Info.FFDiag(E);
3248 return false;
3249 }
3250
3251 ResultElements.emplace_back(Args&: LHSFloat);
3252 }
3253 }
3254
3255 LHSValue = APValue(ResultElements.data(), ResultElements.size());
3256 return true;
3257}
3258
3259/// Cast an lvalue referring to a base subobject to a derived class, by
3260/// truncating the lvalue's path to the given length.
3261static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
3262 const RecordDecl *TruncatedType,
3263 unsigned TruncatedElements) {
3264 SubobjectDesignator &D = Result.Designator;
3265
3266 // Check we actually point to a derived class object.
3267 if (TruncatedElements == D.Entries.size())
3268 return true;
3269 assert(TruncatedElements >= D.MostDerivedPathLength &&
3270 "not casting to a derived class");
3271 if (!Result.checkSubobject(Info, E, CSK: CSK_Derived))
3272 return false;
3273
3274 // Truncate the path to the subobject, and remove any derived-to-base offsets.
3275 const RecordDecl *RD = TruncatedType;
3276 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
3277 if (RD->isInvalidDecl()) return false;
3278 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
3279 const CXXRecordDecl *Base = getAsBaseClass(E: D.Entries[I]);
3280 if (isVirtualBaseClass(E: D.Entries[I]))
3281 Result.Offset -= Layout.getVBaseClassOffset(VBase: Base);
3282 else
3283 Result.Offset -= Layout.getBaseClassOffset(Base);
3284 RD = Base;
3285 }
3286 D.Entries.resize(N: TruncatedElements);
3287 return true;
3288}
3289
3290static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3291 const CXXRecordDecl *Derived,
3292 const CXXRecordDecl *Base,
3293 const ASTRecordLayout *RL = nullptr) {
3294 if (!RL) {
3295 if (Derived->isInvalidDecl()) return false;
3296 RL = &Info.Ctx.getASTRecordLayout(D: Derived);
3297 }
3298
3299 Obj.addDecl(Info, E, D: Base, /*Virtual*/ false);
3300 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
3301 return true;
3302}
3303
3304static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3305 const CXXRecordDecl *DerivedDecl,
3306 const CXXBaseSpecifier *Base) {
3307 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
3308
3309 if (!Base->isVirtual())
3310 return HandleLValueDirectBase(Info, E, Obj, Derived: DerivedDecl, Base: BaseDecl);
3311
3312 SubobjectDesignator &D = Obj.Designator;
3313 if (D.Invalid)
3314 return false;
3315
3316 // Extract most-derived object and corresponding type.
3317 // FIXME: After implementing P2280R4 it became possible to get references
3318 // here. We do MostDerivedType->getAsCXXRecordDecl() in several other
3319 // locations and if we see crashes in those locations in the future
3320 // it may make more sense to move this fix into Lvalue::set.
3321 DerivedDecl = D.MostDerivedType.getNonReferenceType()->getAsCXXRecordDecl();
3322 if (!CastToDerivedClass(Info, E, Result&: Obj, TruncatedType: DerivedDecl, TruncatedElements: D.MostDerivedPathLength))
3323 return false;
3324
3325 // Find the virtual base class.
3326 if (DerivedDecl->isInvalidDecl()) return false;
3327 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: DerivedDecl);
3328 Obj.addDecl(Info, E, D: BaseDecl, /*Virtual*/ true);
3329 Obj.getLValueOffset() += Layout.getVBaseClassOffset(VBase: BaseDecl);
3330 return true;
3331}
3332
3333static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
3334 QualType Type, LValue &Result) {
3335 for (CastExpr::path_const_iterator PathI = E->path_begin(),
3336 PathE = E->path_end();
3337 PathI != PathE; ++PathI) {
3338 if (!HandleLValueBase(Info, E, Obj&: Result, DerivedDecl: Type->getAsCXXRecordDecl(),
3339 Base: *PathI))
3340 return false;
3341 Type = (*PathI)->getType();
3342 }
3343 return true;
3344}
3345
3346/// Cast an lvalue referring to a derived class to a known base subobject.
3347static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
3348 const CXXRecordDecl *DerivedRD,
3349 const CXXRecordDecl *BaseRD) {
3350 CXXBasePaths Paths(/*FindAmbiguities=*/false,
3351 /*RecordPaths=*/true, /*DetectVirtual=*/false);
3352 if (!DerivedRD->isDerivedFrom(Base: BaseRD, Paths))
3353 llvm_unreachable("Class must be derived from the passed in base class!");
3354
3355 for (CXXBasePathElement &Elem : Paths.front())
3356 if (!HandleLValueBase(Info, E, Obj&: Result, DerivedDecl: Elem.Class, Base: Elem.Base))
3357 return false;
3358 return true;
3359}
3360
3361/// Update LVal to refer to the given field, which must be a member of the type
3362/// currently described by LVal.
3363static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
3364 const FieldDecl *FD,
3365 const ASTRecordLayout *RL = nullptr) {
3366 if (!RL) {
3367 if (FD->getParent()->isInvalidDecl()) return false;
3368 RL = &Info.Ctx.getASTRecordLayout(D: FD->getParent());
3369 }
3370
3371 unsigned I = FD->getFieldIndex();
3372 LVal.addDecl(Info, E, D: FD);
3373 LVal.adjustOffset(N: Info.Ctx.toCharUnitsFromBits(BitSize: RL->getFieldOffset(FieldNo: I)));
3374 return true;
3375}
3376
3377/// Update LVal to refer to the given indirect field.
3378static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
3379 LValue &LVal,
3380 const IndirectFieldDecl *IFD) {
3381 for (const auto *C : IFD->chain())
3382 if (!HandleLValueMember(Info, E, LVal, FD: cast<FieldDecl>(Val: C)))
3383 return false;
3384 return true;
3385}
3386
3387enum class SizeOfType {
3388 SizeOf,
3389 DataSizeOf,
3390};
3391
3392/// Get the size of the given type in char units.
3393static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, QualType Type,
3394 CharUnits &Size, SizeOfType SOT = SizeOfType::SizeOf) {
3395 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
3396 // extension.
3397 if (Type->isVoidType() || Type->isFunctionType()) {
3398 Size = CharUnits::One();
3399 return true;
3400 }
3401
3402 if (Type->isDependentType()) {
3403 Info.FFDiag(Loc);
3404 return false;
3405 }
3406
3407 if (!Type->isConstantSizeType()) {
3408 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
3409 // FIXME: Better diagnostic.
3410 Info.FFDiag(Loc);
3411 return false;
3412 }
3413
3414 if (SOT == SizeOfType::SizeOf)
3415 Size = Info.Ctx.getTypeSizeInChars(T: Type);
3416 else
3417 Size = Info.Ctx.getTypeInfoDataSizeInChars(T: Type).Width;
3418 return true;
3419}
3420
3421/// Update a pointer value to model pointer arithmetic.
3422/// \param Info - Information about the ongoing evaluation.
3423/// \param E - The expression being evaluated, for diagnostic purposes.
3424/// \param LVal - The pointer value to be updated.
3425/// \param EltTy - The pointee type represented by LVal.
3426/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
3427static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3428 LValue &LVal, QualType EltTy,
3429 APSInt Adjustment) {
3430 CharUnits SizeOfPointee;
3431 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: EltTy, Size&: SizeOfPointee))
3432 return false;
3433
3434 LVal.adjustOffsetAndIndex(Info, E, Index: Adjustment, ElementSize: SizeOfPointee);
3435 return true;
3436}
3437
3438static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3439 LValue &LVal, QualType EltTy,
3440 int64_t Adjustment) {
3441 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
3442 Adjustment: APSInt::get(X: Adjustment));
3443}
3444
3445/// Update an lvalue to refer to a component of a complex number.
3446/// \param Info - Information about the ongoing evaluation.
3447/// \param LVal - The lvalue to be updated.
3448/// \param EltTy - The complex number's component type.
3449/// \param Imag - False for the real component, true for the imaginary.
3450static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
3451 LValue &LVal, QualType EltTy,
3452 bool Imag) {
3453 if (Imag) {
3454 CharUnits SizeOfComponent;
3455 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: EltTy, Size&: SizeOfComponent))
3456 return false;
3457 LVal.Offset += SizeOfComponent;
3458 }
3459 LVal.addComplex(Info, E, EltTy, Imag);
3460 return true;
3461}
3462
3463static bool HandleLValueVectorElement(EvalInfo &Info, const Expr *E,
3464 LValue &LVal, QualType EltTy,
3465 uint64_t Size, uint64_t Idx) {
3466 if (Idx) {
3467 CharUnits SizeOfElement;
3468 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: EltTy, Size&: SizeOfElement))
3469 return false;
3470 LVal.Offset += SizeOfElement * Idx;
3471 }
3472 LVal.addVectorElement(Info, E, EltTy, Size, Idx);
3473 return true;
3474}
3475
3476/// Try to evaluate the initializer for a variable declaration.
3477///
3478/// \param Info Information about the ongoing evaluation.
3479/// \param E An expression to be used when printing diagnostics.
3480/// \param VD The variable whose initializer should be obtained.
3481/// \param Version The version of the variable within the frame.
3482/// \param Frame The frame in which the variable was created. Must be null
3483/// if this variable is not local to the evaluation.
3484/// \param Result Filled in with a pointer to the value of the variable.
3485static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
3486 const VarDecl *VD, CallStackFrame *Frame,
3487 unsigned Version, APValue *&Result) {
3488 // C++23 [expr.const]p8 If we have a reference type allow unknown references
3489 // and pointers.
3490 bool AllowConstexprUnknown =
3491 Info.getLangOpts().CPlusPlus23 && VD->getType()->isReferenceType();
3492
3493 APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
3494
3495 auto CheckUninitReference = [&](bool IsLocalVariable) {
3496 if (!Result->hasValue() && VD->getType()->isReferenceType()) {
3497 // C++23 [expr.const]p8
3498 // ... For such an object that is not usable in constant expressions, the
3499 // dynamic type of the object is constexpr-unknown. For such a reference
3500 // that is not usable in constant expressions, the reference is treated
3501 // as binding to an unspecified object of the referenced type whose
3502 // lifetime and that of all subobjects includes the entire constant
3503 // evaluation and whose dynamic type is constexpr-unknown.
3504 //
3505 // Variables that are part of the current evaluation are not
3506 // constexpr-unknown.
3507 if (!AllowConstexprUnknown || IsLocalVariable) {
3508 if (!Info.checkingPotentialConstantExpression())
3509 Info.FFDiag(E, DiagId: diag::note_constexpr_use_uninit_reference);
3510 return false;
3511 }
3512 Result = &Info.CurrentCall->createConstexprUnknownAPValues(Key: VD, Base);
3513 }
3514 return true;
3515 };
3516
3517 // If this is a local variable, dig out its value.
3518 if (Frame) {
3519 Result = Frame->getTemporary(Key: VD, Version);
3520 if (Result)
3521 return CheckUninitReference(/*IsLocalVariable=*/true);
3522
3523 if (!isa<ParmVarDecl>(Val: VD)) {
3524 // Assume variables referenced within a lambda's call operator that were
3525 // not declared within the call operator are captures and during checking
3526 // of a potential constant expression, assume they are unknown constant
3527 // expressions.
3528 assert(isLambdaCallOperator(Frame->Callee) &&
3529 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
3530 "missing value for local variable");
3531 if (Info.checkingPotentialConstantExpression())
3532 return false;
3533 // FIXME: This diagnostic is bogus; we do support captures. Is this code
3534 // still reachable at all?
3535 Info.FFDiag(Loc: E->getBeginLoc(),
3536 DiagId: diag::note_unimplemented_constexpr_lambda_feature_ast)
3537 << "captures not currently allowed";
3538 return false;
3539 }
3540 }
3541
3542 // If we're currently evaluating the initializer of this declaration, use that
3543 // in-flight value.
3544 if (Info.EvaluatingDecl == Base) {
3545 Result = Info.EvaluatingDeclValue;
3546 return CheckUninitReference(/*IsLocalVariable=*/false);
3547 }
3548
3549 // P2280R4 struck the restriction that variable of reference type lifetime
3550 // should begin within the evaluation of E
3551 // Used to be C++20 [expr.const]p5.12.2:
3552 // ... its lifetime began within the evaluation of E;
3553 if (isa<ParmVarDecl>(Val: VD)) {
3554 if (AllowConstexprUnknown) {
3555 Result = &Info.CurrentCall->createConstexprUnknownAPValues(Key: VD, Base);
3556 return true;
3557 }
3558
3559 // Assume parameters of a potential constant expression are usable in
3560 // constant expressions.
3561 if (!Info.checkingPotentialConstantExpression() ||
3562 !Info.CurrentCall->Callee ||
3563 !Info.CurrentCall->Callee->Equals(DC: VD->getDeclContext())) {
3564 if (Info.getLangOpts().CPlusPlus11) {
3565 Info.FFDiag(E, DiagId: diag::note_constexpr_function_param_value_unknown)
3566 << VD;
3567 NoteLValueLocation(Info, Base);
3568 } else {
3569 Info.FFDiag(E);
3570 }
3571 }
3572 return false;
3573 }
3574
3575 if (E->isValueDependent())
3576 return false;
3577
3578 // Dig out the initializer, and use the declaration which it's attached to.
3579 // FIXME: We should eventually check whether the variable has a reachable
3580 // initializing declaration.
3581 const Expr *Init = VD->getAnyInitializer(D&: VD);
3582 // P2280R4 struck the restriction that variable of reference type should have
3583 // a preceding initialization.
3584 // Used to be C++20 [expr.const]p5.12:
3585 // ... reference has a preceding initialization and either ...
3586 if (!Init && !AllowConstexprUnknown) {
3587 // Don't diagnose during potential constant expression checking; an
3588 // initializer might be added later.
3589 if (!Info.checkingPotentialConstantExpression()) {
3590 Info.FFDiag(E, DiagId: diag::note_constexpr_var_init_unknown, ExtraNotes: 1)
3591 << VD;
3592 NoteLValueLocation(Info, Base);
3593 }
3594 return false;
3595 }
3596
3597 // P2280R4 struck the initialization requirement for variables of reference
3598 // type so we can no longer assume we have an Init.
3599 // Used to be C++20 [expr.const]p5.12:
3600 // ... reference has a preceding initialization and either ...
3601 if (Init && Init->isValueDependent()) {
3602 // The DeclRefExpr is not value-dependent, but the variable it refers to
3603 // has a value-dependent initializer. This should only happen in
3604 // constant-folding cases, where the variable is not actually of a suitable
3605 // type for use in a constant expression (otherwise the DeclRefExpr would
3606 // have been value-dependent too), so diagnose that.
3607 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx));
3608 if (!Info.checkingPotentialConstantExpression()) {
3609 Info.FFDiag(E, DiagId: Info.getLangOpts().CPlusPlus11
3610 ? diag::note_constexpr_ltor_non_constexpr
3611 : diag::note_constexpr_ltor_non_integral, ExtraNotes: 1)
3612 << VD << VD->getType();
3613 NoteLValueLocation(Info, Base);
3614 }
3615 return false;
3616 }
3617
3618 // Check that we can fold the initializer. In C++, we will have already done
3619 // this in the cases where it matters for conformance.
3620 // P2280R4 struck the initialization requirement for variables of reference
3621 // type so we can no longer assume we have an Init.
3622 // Used to be C++20 [expr.const]p5.12:
3623 // ... reference has a preceding initialization and either ...
3624 if (Init && !VD->evaluateValue() && !AllowConstexprUnknown) {
3625 Info.FFDiag(E, DiagId: diag::note_constexpr_var_init_non_constant, ExtraNotes: 1) << VD;
3626 NoteLValueLocation(Info, Base);
3627 return false;
3628 }
3629
3630 // Check that the variable is actually usable in constant expressions. For a
3631 // const integral variable or a reference, we might have a non-constant
3632 // initializer that we can nonetheless evaluate the initializer for. Such
3633 // variables are not usable in constant expressions. In C++98, the
3634 // initializer also syntactically needs to be an ICE.
3635 //
3636 // FIXME: We don't diagnose cases that aren't potentially usable in constant
3637 // expressions here; doing so would regress diagnostics for things like
3638 // reading from a volatile constexpr variable.
3639 if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() &&
3640 VD->mightBeUsableInConstantExpressions(C: Info.Ctx) &&
3641 !AllowConstexprUnknown) ||
3642 ((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) &&
3643 !Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Context: Info.Ctx))) {
3644 if (Init) {
3645 Info.CCEDiag(E, DiagId: diag::note_constexpr_var_init_non_constant, ExtraNotes: 1) << VD;
3646 NoteLValueLocation(Info, Base);
3647 } else {
3648 Info.CCEDiag(E);
3649 }
3650 }
3651
3652 // Never use the initializer of a weak variable, not even for constant
3653 // folding. We can't be sure that this is the definition that will be used.
3654 if (VD->isWeak()) {
3655 Info.FFDiag(E, DiagId: diag::note_constexpr_var_init_weak) << VD;
3656 NoteLValueLocation(Info, Base);
3657 return false;
3658 }
3659
3660 Result = VD->getEvaluatedValue();
3661
3662 if (!Result) {
3663 if (AllowConstexprUnknown)
3664 Result = &Info.CurrentCall->createConstexprUnknownAPValues(Key: VD, Base);
3665 else
3666 return false;
3667 }
3668
3669 return CheckUninitReference(/*IsLocalVariable=*/false);
3670}
3671
3672/// Get the base index of the given base class within an APValue representing
3673/// the given derived class.
3674static unsigned getBaseIndex(const CXXRecordDecl *Derived,
3675 const CXXRecordDecl *Base) {
3676 Base = Base->getCanonicalDecl();
3677 unsigned Index = 0;
3678 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
3679 E = Derived->bases_end(); I != E; ++I, ++Index) {
3680 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
3681 return Index;
3682 }
3683
3684 llvm_unreachable("base class missing from derived class's bases list");
3685}
3686
3687/// Extract the value of a character from a string literal.
3688static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
3689 uint64_t Index) {
3690 assert(!isa<SourceLocExpr>(Lit) &&
3691 "SourceLocExpr should have already been converted to a StringLiteral");
3692
3693 // FIXME: Support MakeStringConstant
3694 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Val: Lit)) {
3695 std::string Str;
3696 Info.Ctx.getObjCEncodingForType(T: ObjCEnc->getEncodedType(), S&: Str);
3697 assert(Index <= Str.size() && "Index too large");
3698 return APSInt::getUnsigned(X: Str.c_str()[Index]);
3699 }
3700
3701 if (auto PE = dyn_cast<PredefinedExpr>(Val: Lit))
3702 Lit = PE->getFunctionName();
3703 const StringLiteral *S = cast<StringLiteral>(Val: Lit);
3704 const ConstantArrayType *CAT =
3705 Info.Ctx.getAsConstantArrayType(T: S->getType());
3706 assert(CAT && "string literal isn't an array");
3707 QualType CharType = CAT->getElementType();
3708 assert(CharType->isIntegerType() && "unexpected character type");
3709 APSInt Value(Info.Ctx.getTypeSize(T: CharType),
3710 CharType->isUnsignedIntegerType());
3711 if (Index < S->getLength())
3712 Value = S->getCodeUnit(i: Index);
3713 return Value;
3714}
3715
3716// Expand a string literal into an array of characters.
3717//
3718// FIXME: This is inefficient; we should probably introduce something similar
3719// to the LLVM ConstantDataArray to make this cheaper.
3720static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
3721 APValue &Result,
3722 QualType AllocType = QualType()) {
3723 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
3724 T: AllocType.isNull() ? S->getType() : AllocType);
3725 assert(CAT && "string literal isn't an array");
3726 QualType CharType = CAT->getElementType();
3727 assert(CharType->isIntegerType() && "unexpected character type");
3728
3729 unsigned Elts = CAT->getZExtSize();
3730 Result = APValue(APValue::UninitArray(),
3731 std::min(a: S->getLength(), b: Elts), Elts);
3732 APSInt Value(Info.Ctx.getTypeSize(T: CharType),
3733 CharType->isUnsignedIntegerType());
3734 if (Result.hasArrayFiller())
3735 Result.getArrayFiller() = APValue(Value);
3736 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
3737 Value = S->getCodeUnit(i: I);
3738 Result.getArrayInitializedElt(I) = APValue(Value);
3739 }
3740}
3741
3742// Expand an array so that it has more than Index filled elements.
3743static void expandArray(APValue &Array, unsigned Index) {
3744 unsigned Size = Array.getArraySize();
3745 assert(Index < Size);
3746
3747 // Always at least double the number of elements for which we store a value.
3748 unsigned OldElts = Array.getArrayInitializedElts();
3749 unsigned NewElts = std::max(a: Index+1, b: OldElts * 2);
3750 NewElts = std::min(a: Size, b: std::max(a: NewElts, b: 8u));
3751
3752 // Copy the data across.
3753 APValue NewValue(APValue::UninitArray(), NewElts, Size);
3754 for (unsigned I = 0; I != OldElts; ++I)
3755 NewValue.getArrayInitializedElt(I).swap(RHS&: Array.getArrayInitializedElt(I));
3756 for (unsigned I = OldElts; I != NewElts; ++I)
3757 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
3758 if (NewValue.hasArrayFiller())
3759 NewValue.getArrayFiller() = Array.getArrayFiller();
3760 Array.swap(RHS&: NewValue);
3761}
3762
3763/// Determine whether a type would actually be read by an lvalue-to-rvalue
3764/// conversion. If it's of class type, we may assume that the copy operation
3765/// is trivial. Note that this is never true for a union type with fields
3766/// (because the copy always "reads" the active member) and always true for
3767/// a non-class type.
3768static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3769static bool isReadByLvalueToRvalueConversion(QualType T) {
3770 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3771 return !RD || isReadByLvalueToRvalueConversion(RD);
3772}
3773static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
3774 // FIXME: A trivial copy of a union copies the object representation, even if
3775 // the union is empty.
3776 if (RD->isUnion())
3777 return !RD->field_empty();
3778 if (RD->isEmpty())
3779 return false;
3780
3781 for (auto *Field : RD->fields())
3782 if (!Field->isUnnamedBitField() &&
3783 isReadByLvalueToRvalueConversion(T: Field->getType()))
3784 return true;
3785
3786 for (auto &BaseSpec : RD->bases())
3787 if (isReadByLvalueToRvalueConversion(T: BaseSpec.getType()))
3788 return true;
3789
3790 return false;
3791}
3792
3793/// Diagnose an attempt to read from any unreadable field within the specified
3794/// type, which might be a class type.
3795static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
3796 QualType T) {
3797 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3798 if (!RD)
3799 return false;
3800
3801 if (!RD->hasMutableFields())
3802 return false;
3803
3804 for (auto *Field : RD->fields()) {
3805 // If we're actually going to read this field in some way, then it can't
3806 // be mutable. If we're in a union, then assigning to a mutable field
3807 // (even an empty one) can change the active member, so that's not OK.
3808 // FIXME: Add core issue number for the union case.
3809 if (Field->isMutable() &&
3810 (RD->isUnion() || isReadByLvalueToRvalueConversion(T: Field->getType()))) {
3811 Info.FFDiag(E, DiagId: diag::note_constexpr_access_mutable, ExtraNotes: 1) << AK << Field;
3812 Info.Note(Loc: Field->getLocation(), DiagId: diag::note_declared_at);
3813 return true;
3814 }
3815
3816 if (diagnoseMutableFields(Info, E, AK, T: Field->getType()))
3817 return true;
3818 }
3819
3820 for (auto &BaseSpec : RD->bases())
3821 if (diagnoseMutableFields(Info, E, AK, T: BaseSpec.getType()))
3822 return true;
3823
3824 // All mutable fields were empty, and thus not actually read.
3825 return false;
3826}
3827
3828static bool lifetimeStartedInEvaluation(EvalInfo &Info,
3829 APValue::LValueBase Base,
3830 bool MutableSubobject = false) {
3831 // A temporary or transient heap allocation we created.
3832 if (Base.getCallIndex() || Base.is<DynamicAllocLValue>())
3833 return true;
3834
3835 switch (Info.IsEvaluatingDecl) {
3836 case EvalInfo::EvaluatingDeclKind::None:
3837 return false;
3838
3839 case EvalInfo::EvaluatingDeclKind::Ctor:
3840 // The variable whose initializer we're evaluating.
3841 if (Info.EvaluatingDecl == Base)
3842 return true;
3843
3844 // A temporary lifetime-extended by the variable whose initializer we're
3845 // evaluating.
3846 if (auto *BaseE = Base.dyn_cast<const Expr *>())
3847 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(Val: BaseE))
3848 return Info.EvaluatingDecl == BaseMTE->getExtendingDecl();
3849 return false;
3850
3851 case EvalInfo::EvaluatingDeclKind::Dtor:
3852 // C++2a [expr.const]p6:
3853 // [during constant destruction] the lifetime of a and its non-mutable
3854 // subobjects (but not its mutable subobjects) [are] considered to start
3855 // within e.
3856 if (MutableSubobject || Base != Info.EvaluatingDecl)
3857 return false;
3858 // FIXME: We can meaningfully extend this to cover non-const objects, but
3859 // we will need special handling: we should be able to access only
3860 // subobjects of such objects that are themselves declared const.
3861 QualType T = getType(B: Base);
3862 return T.isConstQualified() || T->isReferenceType();
3863 }
3864
3865 llvm_unreachable("unknown evaluating decl kind");
3866}
3867
3868static bool CheckArraySize(EvalInfo &Info, const ConstantArrayType *CAT,
3869 SourceLocation CallLoc = {}) {
3870 return Info.CheckArraySize(
3871 Loc: CAT->getSizeExpr() ? CAT->getSizeExpr()->getBeginLoc() : CallLoc,
3872 BitWidth: CAT->getNumAddressingBits(Context: Info.Ctx), ElemCount: CAT->getZExtSize(),
3873 /*Diag=*/true);
3874}
3875
3876namespace {
3877/// A handle to a complete object (an object that is not a subobject of
3878/// another object).
3879struct CompleteObject {
3880 /// The identity of the object.
3881 APValue::LValueBase Base;
3882 /// The value of the complete object.
3883 APValue *Value;
3884 /// The type of the complete object.
3885 QualType Type;
3886
3887 CompleteObject() : Value(nullptr) {}
3888 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
3889 : Base(Base), Value(Value), Type(Type) {}
3890
3891 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
3892 // If this isn't a "real" access (eg, if it's just accessing the type
3893 // info), allow it. We assume the type doesn't change dynamically for
3894 // subobjects of constexpr objects (even though we'd hit UB here if it
3895 // did). FIXME: Is this right?
3896 if (!isAnyAccess(AK))
3897 return true;
3898
3899 // In C++14 onwards, it is permitted to read a mutable member whose
3900 // lifetime began within the evaluation.
3901 // FIXME: Should we also allow this in C++11?
3902 if (!Info.getLangOpts().CPlusPlus14 &&
3903 AK != AccessKinds::AK_IsWithinLifetime)
3904 return false;
3905 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
3906 }
3907
3908 explicit operator bool() const { return !Type.isNull(); }
3909};
3910} // end anonymous namespace
3911
3912static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
3913 bool IsMutable = false) {
3914 // C++ [basic.type.qualifier]p1:
3915 // - A const object is an object of type const T or a non-mutable subobject
3916 // of a const object.
3917 if (ObjType.isConstQualified() && !IsMutable)
3918 SubobjType.addConst();
3919 // - A volatile object is an object of type const T or a subobject of a
3920 // volatile object.
3921 if (ObjType.isVolatileQualified())
3922 SubobjType.addVolatile();
3923 return SubobjType;
3924}
3925
3926/// Find the designated sub-object of an rvalue.
3927template <typename SubobjectHandler>
3928static typename SubobjectHandler::result_type
3929findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
3930 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
3931 if (Sub.Invalid)
3932 // A diagnostic will have already been produced.
3933 return handler.failed();
3934 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
3935 if (Info.getLangOpts().CPlusPlus11)
3936 Info.FFDiag(E, DiagId: Sub.isOnePastTheEnd()
3937 ? diag::note_constexpr_access_past_end
3938 : diag::note_constexpr_access_unsized_array)
3939 << handler.AccessKind;
3940 else
3941 Info.FFDiag(E);
3942 return handler.failed();
3943 }
3944
3945 APValue *O = Obj.Value;
3946 QualType ObjType = Obj.Type;
3947 const FieldDecl *LastField = nullptr;
3948 const FieldDecl *VolatileField = nullptr;
3949
3950 // C++23 [expr.const]p8 If we have an unknown reference or pointers and it
3951 // does not have a value then bail out.
3952 if (O->allowConstexprUnknown() && !O->hasValue())
3953 return false;
3954
3955 // Walk the designator's path to find the subobject.
3956 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
3957 // Reading an indeterminate value is undefined, but assigning over one is OK.
3958 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
3959 (O->isIndeterminate() &&
3960 !isValidIndeterminateAccess(handler.AccessKind))) {
3961 // Object has ended lifetime.
3962 // If I is non-zero, some subobject (member or array element) of a
3963 // complete object has ended its lifetime, so this is valid for
3964 // IsWithinLifetime, resulting in false.
3965 if (I != 0 && handler.AccessKind == AK_IsWithinLifetime)
3966 return false;
3967 if (!Info.checkingPotentialConstantExpression())
3968 Info.FFDiag(E, DiagId: diag::note_constexpr_access_uninit)
3969 << handler.AccessKind << O->isIndeterminate()
3970 << E->getSourceRange();
3971 return handler.failed();
3972 }
3973
3974 // C++ [class.ctor]p5, C++ [class.dtor]p5:
3975 // const and volatile semantics are not applied on an object under
3976 // {con,de}struction.
3977 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
3978 ObjType->isRecordType() &&
3979 Info.isEvaluatingCtorDtor(
3980 Base: Obj.Base, Path: ArrayRef(Sub.Entries.begin(), Sub.Entries.begin() + I)) !=
3981 ConstructionPhase::None) {
3982 ObjType = Info.Ctx.getCanonicalType(T: ObjType);
3983 ObjType.removeLocalConst();
3984 ObjType.removeLocalVolatile();
3985 }
3986
3987 // If this is our last pass, check that the final object type is OK.
3988 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
3989 // Accesses to volatile objects are prohibited.
3990 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
3991 if (Info.getLangOpts().CPlusPlus) {
3992 int DiagKind;
3993 SourceLocation Loc;
3994 const NamedDecl *Decl = nullptr;
3995 if (VolatileField) {
3996 DiagKind = 2;
3997 Loc = VolatileField->getLocation();
3998 Decl = VolatileField;
3999 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
4000 DiagKind = 1;
4001 Loc = VD->getLocation();
4002 Decl = VD;
4003 } else {
4004 DiagKind = 0;
4005 if (auto *E = Obj.Base.dyn_cast<const Expr *>())
4006 Loc = E->getExprLoc();
4007 }
4008 Info.FFDiag(E, DiagId: diag::note_constexpr_access_volatile_obj, ExtraNotes: 1)
4009 << handler.AccessKind << DiagKind << Decl;
4010 Info.Note(Loc, DiagId: diag::note_constexpr_volatile_here) << DiagKind;
4011 } else {
4012 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
4013 }
4014 return handler.failed();
4015 }
4016
4017 // If we are reading an object of class type, there may still be more
4018 // things we need to check: if there are any mutable subobjects, we
4019 // cannot perform this read. (This only happens when performing a trivial
4020 // copy or assignment.)
4021 if (ObjType->isRecordType() &&
4022 !Obj.mayAccessMutableMembers(Info, AK: handler.AccessKind) &&
4023 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
4024 return handler.failed();
4025 }
4026
4027 if (I == N) {
4028 if (!handler.found(*O, ObjType))
4029 return false;
4030
4031 // If we modified a bit-field, truncate it to the right width.
4032 if (isModification(handler.AccessKind) &&
4033 LastField && LastField->isBitField() &&
4034 !truncateBitfieldValue(Info, E, Value&: *O, FD: LastField))
4035 return false;
4036
4037 return true;
4038 }
4039
4040 LastField = nullptr;
4041 if (ObjType->isArrayType()) {
4042 // Next subobject is an array element.
4043 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T: ObjType);
4044 assert(CAT && "vla in literal type?");
4045 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
4046 if (CAT->getSize().ule(RHS: Index)) {
4047 // Note, it should not be possible to form a pointer with a valid
4048 // designator which points more than one past the end of the array.
4049 if (Info.getLangOpts().CPlusPlus11)
4050 Info.FFDiag(E, DiagId: diag::note_constexpr_access_past_end)
4051 << handler.AccessKind;
4052 else
4053 Info.FFDiag(E);
4054 return handler.failed();
4055 }
4056
4057 ObjType = CAT->getElementType();
4058
4059 if (O->getArrayInitializedElts() > Index)
4060 O = &O->getArrayInitializedElt(I: Index);
4061 else if (!isRead(handler.AccessKind)) {
4062 if (!CheckArraySize(Info, CAT, CallLoc: E->getExprLoc()))
4063 return handler.failed();
4064
4065 expandArray(Array&: *O, Index);
4066 O = &O->getArrayInitializedElt(I: Index);
4067 } else
4068 O = &O->getArrayFiller();
4069 } else if (ObjType->isAnyComplexType()) {
4070 // Next subobject is a complex number.
4071 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
4072 if (Index > 1) {
4073 if (Info.getLangOpts().CPlusPlus11)
4074 Info.FFDiag(E, DiagId: diag::note_constexpr_access_past_end)
4075 << handler.AccessKind;
4076 else
4077 Info.FFDiag(E);
4078 return handler.failed();
4079 }
4080
4081 ObjType = getSubobjectType(
4082 ObjType, SubobjType: ObjType->castAs<ComplexType>()->getElementType());
4083
4084 assert(I == N - 1 && "extracting subobject of scalar?");
4085 if (O->isComplexInt()) {
4086 return handler.found(Index ? O->getComplexIntImag()
4087 : O->getComplexIntReal(), ObjType);
4088 } else {
4089 assert(O->isComplexFloat());
4090 return handler.found(Index ? O->getComplexFloatImag()
4091 : O->getComplexFloatReal(), ObjType);
4092 }
4093 } else if (const auto *VT = ObjType->getAs<VectorType>()) {
4094 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
4095 unsigned NumElements = VT->getNumElements();
4096 if (Index == NumElements) {
4097 if (Info.getLangOpts().CPlusPlus11)
4098 Info.FFDiag(E, DiagId: diag::note_constexpr_access_past_end)
4099 << handler.AccessKind;
4100 else
4101 Info.FFDiag(E);
4102 return handler.failed();
4103 }
4104
4105 if (Index > NumElements) {
4106 Info.CCEDiag(E, DiagId: diag::note_constexpr_array_index)
4107 << Index << /*array*/ 0 << NumElements;
4108 return handler.failed();
4109 }
4110
4111 ObjType = VT->getElementType();
4112 assert(I == N - 1 && "extracting subobject of scalar?");
4113 return handler.found(O->getVectorElt(I: Index), ObjType);
4114 } else if (const FieldDecl *Field = getAsField(E: Sub.Entries[I])) {
4115 if (Field->isMutable() &&
4116 !Obj.mayAccessMutableMembers(Info, AK: handler.AccessKind)) {
4117 Info.FFDiag(E, DiagId: diag::note_constexpr_access_mutable, ExtraNotes: 1)
4118 << handler.AccessKind << Field;
4119 Info.Note(Loc: Field->getLocation(), DiagId: diag::note_declared_at);
4120 return handler.failed();
4121 }
4122
4123 // Next subobject is a class, struct or union field.
4124 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
4125 if (RD->isUnion()) {
4126 const FieldDecl *UnionField = O->getUnionField();
4127 if (!UnionField ||
4128 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
4129 if (I == N - 1 && handler.AccessKind == AK_Construct) {
4130 // Placement new onto an inactive union member makes it active.
4131 O->setUnion(Field, Value: APValue());
4132 } else {
4133 // Pointer to/into inactive union member: Not within lifetime
4134 if (handler.AccessKind == AK_IsWithinLifetime)
4135 return false;
4136 // FIXME: If O->getUnionValue() is absent, report that there's no
4137 // active union member rather than reporting the prior active union
4138 // member. We'll need to fix nullptr_t to not use APValue() as its
4139 // representation first.
4140 Info.FFDiag(E, DiagId: diag::note_constexpr_access_inactive_union_member)
4141 << handler.AccessKind << Field << !UnionField << UnionField;
4142 return handler.failed();
4143 }
4144 }
4145 O = &O->getUnionValue();
4146 } else
4147 O = &O->getStructField(i: Field->getFieldIndex());
4148
4149 ObjType = getSubobjectType(ObjType, SubobjType: Field->getType(), IsMutable: Field->isMutable());
4150 LastField = Field;
4151 if (Field->getType().isVolatileQualified())
4152 VolatileField = Field;
4153 } else {
4154 // Next subobject is a base class.
4155 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
4156 const CXXRecordDecl *Base = getAsBaseClass(E: Sub.Entries[I]);
4157 O = &O->getStructBase(i: getBaseIndex(Derived, Base));
4158
4159 ObjType = getSubobjectType(ObjType, SubobjType: Info.Ctx.getRecordType(Decl: Base));
4160 }
4161 }
4162}
4163
4164namespace {
4165struct ExtractSubobjectHandler {
4166 EvalInfo &Info;
4167 const Expr *E;
4168 APValue &Result;
4169 const AccessKinds AccessKind;
4170
4171 typedef bool result_type;
4172 bool failed() { return false; }
4173 bool found(APValue &Subobj, QualType SubobjType) {
4174 Result = Subobj;
4175 if (AccessKind == AK_ReadObjectRepresentation)
4176 return true;
4177 return CheckFullyInitialized(Info, DiagLoc: E->getExprLoc(), Type: SubobjType, Value: Result);
4178 }
4179 bool found(APSInt &Value, QualType SubobjType) {
4180 Result = APValue(Value);
4181 return true;
4182 }
4183 bool found(APFloat &Value, QualType SubobjType) {
4184 Result = APValue(Value);
4185 return true;
4186 }
4187};
4188} // end anonymous namespace
4189
4190/// Extract the designated sub-object of an rvalue.
4191static bool extractSubobject(EvalInfo &Info, const Expr *E,
4192 const CompleteObject &Obj,
4193 const SubobjectDesignator &Sub, APValue &Result,
4194 AccessKinds AK = AK_Read) {
4195 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation);
4196 ExtractSubobjectHandler Handler = {.Info: Info, .E: E, .Result: Result, .AccessKind: AK};
4197 return findSubobject(Info, E, Obj, Sub, handler&: Handler);
4198}
4199
4200namespace {
4201struct ModifySubobjectHandler {
4202 EvalInfo &Info;
4203 APValue &NewVal;
4204 const Expr *E;
4205
4206 typedef bool result_type;
4207 static const AccessKinds AccessKind = AK_Assign;
4208
4209 bool checkConst(QualType QT) {
4210 // Assigning to a const object has undefined behavior.
4211 if (QT.isConstQualified()) {
4212 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_const_type) << QT;
4213 return false;
4214 }
4215 return true;
4216 }
4217
4218 bool failed() { return false; }
4219 bool found(APValue &Subobj, QualType SubobjType) {
4220 if (!checkConst(QT: SubobjType))
4221 return false;
4222 // We've been given ownership of NewVal, so just swap it in.
4223 Subobj.swap(RHS&: NewVal);
4224 return true;
4225 }
4226 bool found(APSInt &Value, QualType SubobjType) {
4227 if (!checkConst(QT: SubobjType))
4228 return false;
4229 if (!NewVal.isInt()) {
4230 // Maybe trying to write a cast pointer value into a complex?
4231 Info.FFDiag(E);
4232 return false;
4233 }
4234 Value = NewVal.getInt();
4235 return true;
4236 }
4237 bool found(APFloat &Value, QualType SubobjType) {
4238 if (!checkConst(QT: SubobjType))
4239 return false;
4240 Value = NewVal.getFloat();
4241 return true;
4242 }
4243};
4244} // end anonymous namespace
4245
4246const AccessKinds ModifySubobjectHandler::AccessKind;
4247
4248/// Update the designated sub-object of an rvalue to the given value.
4249static bool modifySubobject(EvalInfo &Info, const Expr *E,
4250 const CompleteObject &Obj,
4251 const SubobjectDesignator &Sub,
4252 APValue &NewVal) {
4253 ModifySubobjectHandler Handler = { .Info: Info, .NewVal: NewVal, .E: E };
4254 return findSubobject(Info, E, Obj, Sub, handler&: Handler);
4255}
4256
4257/// Find the position where two subobject designators diverge, or equivalently
4258/// the length of the common initial subsequence.
4259static unsigned FindDesignatorMismatch(QualType ObjType,
4260 const SubobjectDesignator &A,
4261 const SubobjectDesignator &B,
4262 bool &WasArrayIndex) {
4263 unsigned I = 0, N = std::min(a: A.Entries.size(), b: B.Entries.size());
4264 for (/**/; I != N; ++I) {
4265 if (!ObjType.isNull() &&
4266 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
4267 // Next subobject is an array element.
4268 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
4269 WasArrayIndex = true;
4270 return I;
4271 }
4272 if (ObjType->isAnyComplexType())
4273 ObjType = ObjType->castAs<ComplexType>()->getElementType();
4274 else
4275 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
4276 } else {
4277 if (A.Entries[I].getAsBaseOrMember() !=
4278 B.Entries[I].getAsBaseOrMember()) {
4279 WasArrayIndex = false;
4280 return I;
4281 }
4282 if (const FieldDecl *FD = getAsField(E: A.Entries[I]))
4283 // Next subobject is a field.
4284 ObjType = FD->getType();
4285 else
4286 // Next subobject is a base class.
4287 ObjType = QualType();
4288 }
4289 }
4290 WasArrayIndex = false;
4291 return I;
4292}
4293
4294/// Determine whether the given subobject designators refer to elements of the
4295/// same array object.
4296static bool AreElementsOfSameArray(QualType ObjType,
4297 const SubobjectDesignator &A,
4298 const SubobjectDesignator &B) {
4299 if (A.Entries.size() != B.Entries.size())
4300 return false;
4301
4302 bool IsArray = A.MostDerivedIsArrayElement;
4303 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
4304 // A is a subobject of the array element.
4305 return false;
4306
4307 // If A (and B) designates an array element, the last entry will be the array
4308 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
4309 // of length 1' case, and the entire path must match.
4310 bool WasArrayIndex;
4311 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
4312 return CommonLength >= A.Entries.size() - IsArray;
4313}
4314
4315/// Find the complete object to which an LValue refers.
4316static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
4317 AccessKinds AK, const LValue &LVal,
4318 QualType LValType) {
4319 if (LVal.InvalidBase) {
4320 Info.FFDiag(E);
4321 return CompleteObject();
4322 }
4323
4324 if (!LVal.Base) {
4325 Info.FFDiag(E, DiagId: diag::note_constexpr_access_null) << AK;
4326 return CompleteObject();
4327 }
4328
4329 CallStackFrame *Frame = nullptr;
4330 unsigned Depth = 0;
4331 if (LVal.getLValueCallIndex()) {
4332 std::tie(args&: Frame, args&: Depth) =
4333 Info.getCallFrameAndDepth(CallIndex: LVal.getLValueCallIndex());
4334 if (!Frame) {
4335 Info.FFDiag(E, DiagId: diag::note_constexpr_lifetime_ended, ExtraNotes: 1)
4336 << AK << LVal.Base.is<const ValueDecl*>();
4337 NoteLValueLocation(Info, Base: LVal.Base);
4338 return CompleteObject();
4339 }
4340 }
4341
4342 bool IsAccess = isAnyAccess(AK);
4343
4344 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
4345 // is not a constant expression (even if the object is non-volatile). We also
4346 // apply this rule to C++98, in order to conform to the expected 'volatile'
4347 // semantics.
4348 if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
4349 if (Info.getLangOpts().CPlusPlus)
4350 Info.FFDiag(E, DiagId: diag::note_constexpr_access_volatile_type)
4351 << AK << LValType;
4352 else
4353 Info.FFDiag(E);
4354 return CompleteObject();
4355 }
4356
4357 // Compute value storage location and type of base object.
4358 APValue *BaseVal = nullptr;
4359 QualType BaseType = getType(B: LVal.Base);
4360
4361 if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl &&
4362 lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4363 // This is the object whose initializer we're evaluating, so its lifetime
4364 // started in the current evaluation.
4365 BaseVal = Info.EvaluatingDeclValue;
4366 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
4367 // Allow reading from a GUID declaration.
4368 if (auto *GD = dyn_cast<MSGuidDecl>(Val: D)) {
4369 if (isModification(AK)) {
4370 // All the remaining cases do not permit modification of the object.
4371 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_global);
4372 return CompleteObject();
4373 }
4374 APValue &V = GD->getAsAPValue();
4375 if (V.isAbsent()) {
4376 Info.FFDiag(E, DiagId: diag::note_constexpr_unsupported_layout)
4377 << GD->getType();
4378 return CompleteObject();
4379 }
4380 return CompleteObject(LVal.Base, &V, GD->getType());
4381 }
4382
4383 // Allow reading the APValue from an UnnamedGlobalConstantDecl.
4384 if (auto *GCD = dyn_cast<UnnamedGlobalConstantDecl>(Val: D)) {
4385 if (isModification(AK)) {
4386 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_global);
4387 return CompleteObject();
4388 }
4389 return CompleteObject(LVal.Base, const_cast<APValue *>(&GCD->getValue()),
4390 GCD->getType());
4391 }
4392
4393 // Allow reading from template parameter objects.
4394 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(Val: D)) {
4395 if (isModification(AK)) {
4396 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_global);
4397 return CompleteObject();
4398 }
4399 return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()),
4400 TPO->getType());
4401 }
4402
4403 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
4404 // In C++11, constexpr, non-volatile variables initialized with constant
4405 // expressions are constant expressions too. Inside constexpr functions,
4406 // parameters are constant expressions even if they're non-const.
4407 // In C++1y, objects local to a constant expression (those with a Frame) are
4408 // both readable and writable inside constant expressions.
4409 // In C, such things can also be folded, although they are not ICEs.
4410 const VarDecl *VD = dyn_cast<VarDecl>(Val: D);
4411 if (VD) {
4412 if (const VarDecl *VDef = VD->getDefinition(C&: Info.Ctx))
4413 VD = VDef;
4414 }
4415 if (!VD || VD->isInvalidDecl()) {
4416 Info.FFDiag(E);
4417 return CompleteObject();
4418 }
4419
4420 bool IsConstant = BaseType.isConstant(Ctx: Info.Ctx);
4421 bool ConstexprVar = false;
4422 if (const auto *VD = dyn_cast_if_present<VarDecl>(
4423 Val: Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()))
4424 ConstexprVar = VD->isConstexpr();
4425
4426 // Unless we're looking at a local variable or argument in a constexpr call,
4427 // the variable we're reading must be const.
4428 if (!Frame) {
4429 if (IsAccess && isa<ParmVarDecl>(Val: VD)) {
4430 // Access of a parameter that's not associated with a frame isn't going
4431 // to work out, but we can leave it to evaluateVarDeclInit to provide a
4432 // suitable diagnostic.
4433 } else if (Info.getLangOpts().CPlusPlus14 &&
4434 lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4435 // OK, we can read and modify an object if we're in the process of
4436 // evaluating its initializer, because its lifetime began in this
4437 // evaluation.
4438 } else if (isModification(AK)) {
4439 // All the remaining cases do not permit modification of the object.
4440 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_global);
4441 return CompleteObject();
4442 } else if (VD->isConstexpr()) {
4443 // OK, we can read this variable.
4444 } else if (Info.getLangOpts().C23 && ConstexprVar) {
4445 Info.FFDiag(E);
4446 return CompleteObject();
4447 } else if (BaseType->isIntegralOrEnumerationType()) {
4448 if (!IsConstant) {
4449 if (!IsAccess)
4450 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4451 if (Info.getLangOpts().CPlusPlus) {
4452 Info.FFDiag(E, DiagId: diag::note_constexpr_ltor_non_const_int, ExtraNotes: 1) << VD;
4453 Info.Note(Loc: VD->getLocation(), DiagId: diag::note_declared_at);
4454 } else {
4455 Info.FFDiag(E);
4456 }
4457 return CompleteObject();
4458 }
4459 } else if (!IsAccess) {
4460 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4461 } else if (IsConstant && Info.checkingPotentialConstantExpression() &&
4462 BaseType->isLiteralType(Ctx: Info.Ctx) && !VD->hasDefinition()) {
4463 // This variable might end up being constexpr. Don't diagnose it yet.
4464 } else if (IsConstant) {
4465 // Keep evaluating to see what we can do. In particular, we support
4466 // folding of const floating-point types, in order to make static const
4467 // data members of such types (supported as an extension) more useful.
4468 if (Info.getLangOpts().CPlusPlus) {
4469 Info.CCEDiag(E, DiagId: Info.getLangOpts().CPlusPlus11
4470 ? diag::note_constexpr_ltor_non_constexpr
4471 : diag::note_constexpr_ltor_non_integral, ExtraNotes: 1)
4472 << VD << BaseType;
4473 Info.Note(Loc: VD->getLocation(), DiagId: diag::note_declared_at);
4474 } else {
4475 Info.CCEDiag(E);
4476 }
4477 } else {
4478 // Never allow reading a non-const value.
4479 if (Info.getLangOpts().CPlusPlus) {
4480 Info.FFDiag(E, DiagId: Info.getLangOpts().CPlusPlus11
4481 ? diag::note_constexpr_ltor_non_constexpr
4482 : diag::note_constexpr_ltor_non_integral, ExtraNotes: 1)
4483 << VD << BaseType;
4484 Info.Note(Loc: VD->getLocation(), DiagId: diag::note_declared_at);
4485 } else {
4486 Info.FFDiag(E);
4487 }
4488 return CompleteObject();
4489 }
4490 }
4491
4492 if (!evaluateVarDeclInit(Info, E, VD, Frame, Version: LVal.getLValueVersion(), Result&: BaseVal))
4493 return CompleteObject();
4494 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
4495 std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
4496 if (!Alloc) {
4497 Info.FFDiag(E, DiagId: diag::note_constexpr_access_deleted_object) << AK;
4498 return CompleteObject();
4499 }
4500 return CompleteObject(LVal.Base, &(*Alloc)->Value,
4501 LVal.Base.getDynamicAllocType());
4502 } else {
4503 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4504
4505 if (!Frame) {
4506 if (const MaterializeTemporaryExpr *MTE =
4507 dyn_cast_or_null<MaterializeTemporaryExpr>(Val: Base)) {
4508 assert(MTE->getStorageDuration() == SD_Static &&
4509 "should have a frame for a non-global materialized temporary");
4510
4511 // C++20 [expr.const]p4: [DR2126]
4512 // An object or reference is usable in constant expressions if it is
4513 // - a temporary object of non-volatile const-qualified literal type
4514 // whose lifetime is extended to that of a variable that is usable
4515 // in constant expressions
4516 //
4517 // C++20 [expr.const]p5:
4518 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
4519 // - a non-volatile glvalue that refers to an object that is usable
4520 // in constant expressions, or
4521 // - a non-volatile glvalue of literal type that refers to a
4522 // non-volatile object whose lifetime began within the evaluation
4523 // of E;
4524 //
4525 // C++11 misses the 'began within the evaluation of e' check and
4526 // instead allows all temporaries, including things like:
4527 // int &&r = 1;
4528 // int x = ++r;
4529 // constexpr int k = r;
4530 // Therefore we use the C++14-onwards rules in C++11 too.
4531 //
4532 // Note that temporaries whose lifetimes began while evaluating a
4533 // variable's constructor are not usable while evaluating the
4534 // corresponding destructor, not even if they're of const-qualified
4535 // types.
4536 if (!MTE->isUsableInConstantExpressions(Context: Info.Ctx) &&
4537 !lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4538 if (!IsAccess)
4539 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4540 Info.FFDiag(E, DiagId: diag::note_constexpr_access_static_temporary, ExtraNotes: 1) << AK;
4541 Info.Note(Loc: MTE->getExprLoc(), DiagId: diag::note_constexpr_temporary_here);
4542 return CompleteObject();
4543 }
4544
4545 BaseVal = MTE->getOrCreateValue(MayCreate: false);
4546 assert(BaseVal && "got reference to unevaluated temporary");
4547 } else {
4548 if (!IsAccess)
4549 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4550 APValue Val;
4551 LVal.moveInto(V&: Val);
4552 Info.FFDiag(E, DiagId: diag::note_constexpr_access_unreadable_object)
4553 << AK
4554 << Val.getAsString(Ctx: Info.Ctx,
4555 Ty: Info.Ctx.getLValueReferenceType(T: LValType));
4556 NoteLValueLocation(Info, Base: LVal.Base);
4557 return CompleteObject();
4558 }
4559 } else {
4560 BaseVal = Frame->getTemporary(Key: Base, Version: LVal.Base.getVersion());
4561 assert(BaseVal && "missing value for temporary");
4562 }
4563 }
4564
4565 // In C++14, we can't safely access any mutable state when we might be
4566 // evaluating after an unmodeled side effect. Parameters are modeled as state
4567 // in the caller, but aren't visible once the call returns, so they can be
4568 // modified in a speculatively-evaluated call.
4569 //
4570 // FIXME: Not all local state is mutable. Allow local constant subobjects
4571 // to be read here (but take care with 'mutable' fields).
4572 unsigned VisibleDepth = Depth;
4573 if (llvm::isa_and_nonnull<ParmVarDecl>(
4574 Val: LVal.Base.dyn_cast<const ValueDecl *>()))
4575 ++VisibleDepth;
4576 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
4577 Info.EvalStatus.HasSideEffects) ||
4578 (isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth))
4579 return CompleteObject();
4580
4581 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
4582}
4583
4584/// Perform an lvalue-to-rvalue conversion on the given glvalue. This
4585/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
4586/// glvalue referred to by an entity of reference type.
4587///
4588/// \param Info - Information about the ongoing evaluation.
4589/// \param Conv - The expression for which we are performing the conversion.
4590/// Used for diagnostics.
4591/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
4592/// case of a non-class type).
4593/// \param LVal - The glvalue on which we are attempting to perform this action.
4594/// \param RVal - The produced value will be placed here.
4595/// \param WantObjectRepresentation - If true, we're looking for the object
4596/// representation rather than the value, and in particular,
4597/// there is no requirement that the result be fully initialized.
4598static bool
4599handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
4600 const LValue &LVal, APValue &RVal,
4601 bool WantObjectRepresentation = false) {
4602 if (LVal.Designator.Invalid)
4603 return false;
4604
4605 // Check for special cases where there is no existing APValue to look at.
4606 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4607
4608 AccessKinds AK =
4609 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;
4610
4611 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
4612 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Val: Base)) {
4613 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
4614 // initializer until now for such expressions. Such an expression can't be
4615 // an ICE in C, so this only matters for fold.
4616 if (Type.isVolatileQualified()) {
4617 Info.FFDiag(E: Conv);
4618 return false;
4619 }
4620
4621 APValue Lit;
4622 if (!Evaluate(Result&: Lit, Info, E: CLE->getInitializer()))
4623 return false;
4624
4625 // According to GCC info page:
4626 //
4627 // 6.28 Compound Literals
4628 //
4629 // As an optimization, G++ sometimes gives array compound literals longer
4630 // lifetimes: when the array either appears outside a function or has a
4631 // const-qualified type. If foo and its initializer had elements of type
4632 // char *const rather than char *, or if foo were a global variable, the
4633 // array would have static storage duration. But it is probably safest
4634 // just to avoid the use of array compound literals in C++ code.
4635 //
4636 // Obey that rule by checking constness for converted array types.
4637
4638 QualType CLETy = CLE->getType();
4639 if (CLETy->isArrayType() && !Type->isArrayType()) {
4640 if (!CLETy.isConstant(Ctx: Info.Ctx)) {
4641 Info.FFDiag(E: Conv);
4642 Info.Note(Loc: CLE->getExprLoc(), DiagId: diag::note_declared_at);
4643 return false;
4644 }
4645 }
4646
4647 CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
4648 return extractSubobject(Info, E: Conv, Obj: LitObj, Sub: LVal.Designator, Result&: RVal, AK);
4649 } else if (isa<StringLiteral>(Val: Base) || isa<PredefinedExpr>(Val: Base)) {
4650 // Special-case character extraction so we don't have to construct an
4651 // APValue for the whole string.
4652 assert(LVal.Designator.Entries.size() <= 1 &&
4653 "Can only read characters from string literals");
4654 if (LVal.Designator.Entries.empty()) {
4655 // Fail for now for LValue to RValue conversion of an array.
4656 // (This shouldn't show up in C/C++, but it could be triggered by a
4657 // weird EvaluateAsRValue call from a tool.)
4658 Info.FFDiag(E: Conv);
4659 return false;
4660 }
4661 if (LVal.Designator.isOnePastTheEnd()) {
4662 if (Info.getLangOpts().CPlusPlus11)
4663 Info.FFDiag(E: Conv, DiagId: diag::note_constexpr_access_past_end) << AK;
4664 else
4665 Info.FFDiag(E: Conv);
4666 return false;
4667 }
4668 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
4669 RVal = APValue(extractStringLiteralCharacter(Info, Lit: Base, Index: CharIndex));
4670 return true;
4671 }
4672 }
4673
4674 CompleteObject Obj = findCompleteObject(Info, E: Conv, AK, LVal, LValType: Type);
4675 return Obj && extractSubobject(Info, E: Conv, Obj, Sub: LVal.Designator, Result&: RVal, AK);
4676}
4677
4678/// Perform an assignment of Val to LVal. Takes ownership of Val.
4679static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
4680 QualType LValType, APValue &Val) {
4681 if (LVal.Designator.Invalid)
4682 return false;
4683
4684 if (!Info.getLangOpts().CPlusPlus14) {
4685 Info.FFDiag(E);
4686 return false;
4687 }
4688
4689 CompleteObject Obj = findCompleteObject(Info, E, AK: AK_Assign, LVal, LValType);
4690 return Obj && modifySubobject(Info, E, Obj, Sub: LVal.Designator, NewVal&: Val);
4691}
4692
4693namespace {
4694struct CompoundAssignSubobjectHandler {
4695 EvalInfo &Info;
4696 const CompoundAssignOperator *E;
4697 QualType PromotedLHSType;
4698 BinaryOperatorKind Opcode;
4699 const APValue &RHS;
4700
4701 static const AccessKinds AccessKind = AK_Assign;
4702
4703 typedef bool result_type;
4704
4705 bool checkConst(QualType QT) {
4706 // Assigning to a const object has undefined behavior.
4707 if (QT.isConstQualified()) {
4708 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_const_type) << QT;
4709 return false;
4710 }
4711 return true;
4712 }
4713
4714 bool failed() { return false; }
4715 bool found(APValue &Subobj, QualType SubobjType) {
4716 switch (Subobj.getKind()) {
4717 case APValue::Int:
4718 return found(Value&: Subobj.getInt(), SubobjType);
4719 case APValue::Float:
4720 return found(Value&: Subobj.getFloat(), SubobjType);
4721 case APValue::ComplexInt:
4722 case APValue::ComplexFloat:
4723 // FIXME: Implement complex compound assignment.
4724 Info.FFDiag(E);
4725 return false;
4726 case APValue::LValue:
4727 return foundPointer(Subobj, SubobjType);
4728 case APValue::Vector:
4729 return foundVector(Value&: Subobj, SubobjType);
4730 case APValue::Indeterminate:
4731 Info.FFDiag(E, DiagId: diag::note_constexpr_access_uninit)
4732 << /*read of=*/0 << /*uninitialized object=*/1
4733 << E->getLHS()->getSourceRange();
4734 return false;
4735 default:
4736 // FIXME: can this happen?
4737 Info.FFDiag(E);
4738 return false;
4739 }
4740 }
4741
4742 bool foundVector(APValue &Value, QualType SubobjType) {
4743 if (!checkConst(QT: SubobjType))
4744 return false;
4745
4746 if (!SubobjType->isVectorType()) {
4747 Info.FFDiag(E);
4748 return false;
4749 }
4750 return handleVectorVectorBinOp(Info, E, Opcode, LHSValue&: Value, RHSValue: RHS);
4751 }
4752
4753 bool found(APSInt &Value, QualType SubobjType) {
4754 if (!checkConst(QT: SubobjType))
4755 return false;
4756
4757 if (!SubobjType->isIntegerType()) {
4758 // We don't support compound assignment on integer-cast-to-pointer
4759 // values.
4760 Info.FFDiag(E);
4761 return false;
4762 }
4763
4764 if (RHS.isInt()) {
4765 APSInt LHS =
4766 HandleIntToIntCast(Info, E, DestType: PromotedLHSType, SrcType: SubobjType, Value);
4767 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS: RHS.getInt(), Result&: LHS))
4768 return false;
4769 Value = HandleIntToIntCast(Info, E, DestType: SubobjType, SrcType: PromotedLHSType, Value: LHS);
4770 return true;
4771 } else if (RHS.isFloat()) {
4772 const FPOptions FPO = E->getFPFeaturesInEffect(
4773 LO: Info.Ctx.getLangOpts());
4774 APFloat FValue(0.0);
4775 return HandleIntToFloatCast(Info, E, FPO, SrcType: SubobjType, Value,
4776 DestType: PromotedLHSType, Result&: FValue) &&
4777 handleFloatFloatBinOp(Info, E, LHS&: FValue, Opcode, RHS: RHS.getFloat()) &&
4778 HandleFloatToIntCast(Info, E, SrcType: PromotedLHSType, Value: FValue, DestType: SubobjType,
4779 Result&: Value);
4780 }
4781
4782 Info.FFDiag(E);
4783 return false;
4784 }
4785 bool found(APFloat &Value, QualType SubobjType) {
4786 return checkConst(QT: SubobjType) &&
4787 HandleFloatToFloatCast(Info, E, SrcType: SubobjType, DestType: PromotedLHSType,
4788 Result&: Value) &&
4789 handleFloatFloatBinOp(Info, E, LHS&: Value, Opcode, RHS: RHS.getFloat()) &&
4790 HandleFloatToFloatCast(Info, E, SrcType: PromotedLHSType, DestType: SubobjType, Result&: Value);
4791 }
4792 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4793 if (!checkConst(QT: SubobjType))
4794 return false;
4795
4796 QualType PointeeType;
4797 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4798 PointeeType = PT->getPointeeType();
4799
4800 if (PointeeType.isNull() || !RHS.isInt() ||
4801 (Opcode != BO_Add && Opcode != BO_Sub)) {
4802 Info.FFDiag(E);
4803 return false;
4804 }
4805
4806 APSInt Offset = RHS.getInt();
4807 if (Opcode == BO_Sub)
4808 negateAsSigned(Int&: Offset);
4809
4810 LValue LVal;
4811 LVal.setFrom(Ctx&: Info.Ctx, V: Subobj);
4812 if (!HandleLValueArrayAdjustment(Info, E, LVal, EltTy: PointeeType, Adjustment: Offset))
4813 return false;
4814 LVal.moveInto(V&: Subobj);
4815 return true;
4816 }
4817};
4818} // end anonymous namespace
4819
4820const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
4821
4822/// Perform a compound assignment of LVal <op>= RVal.
4823static bool handleCompoundAssignment(EvalInfo &Info,
4824 const CompoundAssignOperator *E,
4825 const LValue &LVal, QualType LValType,
4826 QualType PromotedLValType,
4827 BinaryOperatorKind Opcode,
4828 const APValue &RVal) {
4829 if (LVal.Designator.Invalid)
4830 return false;
4831
4832 if (!Info.getLangOpts().CPlusPlus14) {
4833 Info.FFDiag(E);
4834 return false;
4835 }
4836
4837 CompleteObject Obj = findCompleteObject(Info, E, AK: AK_Assign, LVal, LValType);
4838 CompoundAssignSubobjectHandler Handler = { .Info: Info, .E: E, .PromotedLHSType: PromotedLValType, .Opcode: Opcode,
4839 .RHS: RVal };
4840 return Obj && findSubobject(Info, E, Obj, Sub: LVal.Designator, handler&: Handler);
4841}
4842
4843namespace {
4844struct IncDecSubobjectHandler {
4845 EvalInfo &Info;
4846 const UnaryOperator *E;
4847 AccessKinds AccessKind;
4848 APValue *Old;
4849
4850 typedef bool result_type;
4851
4852 bool checkConst(QualType QT) {
4853 // Assigning to a const object has undefined behavior.
4854 if (QT.isConstQualified()) {
4855 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_const_type) << QT;
4856 return false;
4857 }
4858 return true;
4859 }
4860
4861 bool failed() { return false; }
4862 bool found(APValue &Subobj, QualType SubobjType) {
4863 // Stash the old value. Also clear Old, so we don't clobber it later
4864 // if we're post-incrementing a complex.
4865 if (Old) {
4866 *Old = Subobj;
4867 Old = nullptr;
4868 }
4869
4870 switch (Subobj.getKind()) {
4871 case APValue::Int:
4872 return found(Value&: Subobj.getInt(), SubobjType);
4873 case APValue::Float:
4874 return found(Value&: Subobj.getFloat(), SubobjType);
4875 case APValue::ComplexInt:
4876 return found(Value&: Subobj.getComplexIntReal(),
4877 SubobjType: SubobjType->castAs<ComplexType>()->getElementType()
4878 .withCVRQualifiers(CVR: SubobjType.getCVRQualifiers()));
4879 case APValue::ComplexFloat:
4880 return found(Value&: Subobj.getComplexFloatReal(),
4881 SubobjType: SubobjType->castAs<ComplexType>()->getElementType()
4882 .withCVRQualifiers(CVR: SubobjType.getCVRQualifiers()));
4883 case APValue::LValue:
4884 return foundPointer(Subobj, SubobjType);
4885 default:
4886 // FIXME: can this happen?
4887 Info.FFDiag(E);
4888 return false;
4889 }
4890 }
4891 bool found(APSInt &Value, QualType SubobjType) {
4892 if (!checkConst(QT: SubobjType))
4893 return false;
4894
4895 if (!SubobjType->isIntegerType()) {
4896 // We don't support increment / decrement on integer-cast-to-pointer
4897 // values.
4898 Info.FFDiag(E);
4899 return false;
4900 }
4901
4902 if (Old) *Old = APValue(Value);
4903
4904 // bool arithmetic promotes to int, and the conversion back to bool
4905 // doesn't reduce mod 2^n, so special-case it.
4906 if (SubobjType->isBooleanType()) {
4907 if (AccessKind == AK_Increment)
4908 Value = 1;
4909 else
4910 Value = !Value;
4911 return true;
4912 }
4913
4914 bool WasNegative = Value.isNegative();
4915 if (AccessKind == AK_Increment) {
4916 ++Value;
4917
4918 if (!WasNegative && Value.isNegative() && E->canOverflow()) {
4919 APSInt ActualValue(Value, /*IsUnsigned*/true);
4920 return HandleOverflow(Info, E, SrcValue: ActualValue, DestType: SubobjType);
4921 }
4922 } else {
4923 --Value;
4924
4925 if (WasNegative && !Value.isNegative() && E->canOverflow()) {
4926 unsigned BitWidth = Value.getBitWidth();
4927 APSInt ActualValue(Value.sext(width: BitWidth + 1), /*IsUnsigned*/false);
4928 ActualValue.setBit(BitWidth);
4929 return HandleOverflow(Info, E, SrcValue: ActualValue, DestType: SubobjType);
4930 }
4931 }
4932 return true;
4933 }
4934 bool found(APFloat &Value, QualType SubobjType) {
4935 if (!checkConst(QT: SubobjType))
4936 return false;
4937
4938 if (Old) *Old = APValue(Value);
4939
4940 APFloat One(Value.getSemantics(), 1);
4941 llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
4942 APFloat::opStatus St;
4943 if (AccessKind == AK_Increment)
4944 St = Value.add(RHS: One, RM);
4945 else
4946 St = Value.subtract(RHS: One, RM);
4947 return checkFloatingPointResult(Info, E, St);
4948 }
4949 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4950 if (!checkConst(QT: SubobjType))
4951 return false;
4952
4953 QualType PointeeType;
4954 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4955 PointeeType = PT->getPointeeType();
4956 else {
4957 Info.FFDiag(E);
4958 return false;
4959 }
4960
4961 LValue LVal;
4962 LVal.setFrom(Ctx&: Info.Ctx, V: Subobj);
4963 if (!HandleLValueArrayAdjustment(Info, E, LVal, EltTy: PointeeType,
4964 Adjustment: AccessKind == AK_Increment ? 1 : -1))
4965 return false;
4966 LVal.moveInto(V&: Subobj);
4967 return true;
4968 }
4969};
4970} // end anonymous namespace
4971
4972/// Perform an increment or decrement on LVal.
4973static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
4974 QualType LValType, bool IsIncrement, APValue *Old) {
4975 if (LVal.Designator.Invalid)
4976 return false;
4977
4978 if (!Info.getLangOpts().CPlusPlus14) {
4979 Info.FFDiag(E);
4980 return false;
4981 }
4982
4983 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
4984 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
4985 IncDecSubobjectHandler Handler = {.Info: Info, .E: cast<UnaryOperator>(Val: E), .AccessKind: AK, .Old: Old};
4986 return Obj && findSubobject(Info, E, Obj, Sub: LVal.Designator, handler&: Handler);
4987}
4988
4989/// Build an lvalue for the object argument of a member function call.
4990static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
4991 LValue &This) {
4992 if (Object->getType()->isPointerType() && Object->isPRValue())
4993 return EvaluatePointer(E: Object, Result&: This, Info);
4994
4995 if (Object->isGLValue())
4996 return EvaluateLValue(E: Object, Result&: This, Info);
4997
4998 if (Object->getType()->isLiteralType(Ctx: Info.Ctx))
4999 return EvaluateTemporary(E: Object, Result&: This, Info);
5000
5001 if (Object->getType()->isRecordType() && Object->isPRValue())
5002 return EvaluateTemporary(E: Object, Result&: This, Info);
5003
5004 Info.FFDiag(E: Object, DiagId: diag::note_constexpr_nonliteral) << Object->getType();
5005 return false;
5006}
5007
5008/// HandleMemberPointerAccess - Evaluate a member access operation and build an
5009/// lvalue referring to the result.
5010///
5011/// \param Info - Information about the ongoing evaluation.
5012/// \param LV - An lvalue referring to the base of the member pointer.
5013/// \param RHS - The member pointer expression.
5014/// \param IncludeMember - Specifies whether the member itself is included in
5015/// the resulting LValue subobject designator. This is not possible when
5016/// creating a bound member function.
5017/// \return The field or method declaration to which the member pointer refers,
5018/// or 0 if evaluation fails.
5019static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
5020 QualType LVType,
5021 LValue &LV,
5022 const Expr *RHS,
5023 bool IncludeMember = true) {
5024 MemberPtr MemPtr;
5025 if (!EvaluateMemberPointer(E: RHS, Result&: MemPtr, Info))
5026 return nullptr;
5027
5028 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
5029 // member value, the behavior is undefined.
5030 if (!MemPtr.getDecl()) {
5031 // FIXME: Specific diagnostic.
5032 Info.FFDiag(E: RHS);
5033 return nullptr;
5034 }
5035
5036 if (MemPtr.isDerivedMember()) {
5037 // This is a member of some derived class. Truncate LV appropriately.
5038 // The end of the derived-to-base path for the base object must match the
5039 // derived-to-base path for the member pointer.
5040 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
5041 LV.Designator.Entries.size()) {
5042 Info.FFDiag(E: RHS);
5043 return nullptr;
5044 }
5045 unsigned PathLengthToMember =
5046 LV.Designator.Entries.size() - MemPtr.Path.size();
5047 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
5048 const CXXRecordDecl *LVDecl = getAsBaseClass(
5049 E: LV.Designator.Entries[PathLengthToMember + I]);
5050 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
5051 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
5052 Info.FFDiag(E: RHS);
5053 return nullptr;
5054 }
5055 }
5056
5057 // Truncate the lvalue to the appropriate derived class.
5058 if (!CastToDerivedClass(Info, E: RHS, Result&: LV, TruncatedType: MemPtr.getContainingRecord(),
5059 TruncatedElements: PathLengthToMember))
5060 return nullptr;
5061 } else if (!MemPtr.Path.empty()) {
5062 // Extend the LValue path with the member pointer's path.
5063 LV.Designator.Entries.reserve(N: LV.Designator.Entries.size() +
5064 MemPtr.Path.size() + IncludeMember);
5065
5066 // Walk down to the appropriate base class.
5067 if (const PointerType *PT = LVType->getAs<PointerType>())
5068 LVType = PT->getPointeeType();
5069 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
5070 assert(RD && "member pointer access on non-class-type expression");
5071 // The first class in the path is that of the lvalue.
5072 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
5073 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
5074 if (!HandleLValueDirectBase(Info, E: RHS, Obj&: LV, Derived: RD, Base))
5075 return nullptr;
5076 RD = Base;
5077 }
5078 // Finally cast to the class containing the member.
5079 if (!HandleLValueDirectBase(Info, E: RHS, Obj&: LV, Derived: RD,
5080 Base: MemPtr.getContainingRecord()))
5081 return nullptr;
5082 }
5083
5084 // Add the member. Note that we cannot build bound member functions here.
5085 if (IncludeMember) {
5086 if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: MemPtr.getDecl())) {
5087 if (!HandleLValueMember(Info, E: RHS, LVal&: LV, FD))
5088 return nullptr;
5089 } else if (const IndirectFieldDecl *IFD =
5090 dyn_cast<IndirectFieldDecl>(Val: MemPtr.getDecl())) {
5091 if (!HandleLValueIndirectMember(Info, E: RHS, LVal&: LV, IFD))
5092 return nullptr;
5093 } else {
5094 llvm_unreachable("can't construct reference to bound member function");
5095 }
5096 }
5097
5098 return MemPtr.getDecl();
5099}
5100
5101static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
5102 const BinaryOperator *BO,
5103 LValue &LV,
5104 bool IncludeMember = true) {
5105 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
5106
5107 if (!EvaluateObjectArgument(Info, Object: BO->getLHS(), This&: LV)) {
5108 if (Info.noteFailure()) {
5109 MemberPtr MemPtr;
5110 EvaluateMemberPointer(E: BO->getRHS(), Result&: MemPtr, Info);
5111 }
5112 return nullptr;
5113 }
5114
5115 return HandleMemberPointerAccess(Info, LVType: BO->getLHS()->getType(), LV,
5116 RHS: BO->getRHS(), IncludeMember);
5117}
5118
5119/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
5120/// the provided lvalue, which currently refers to the base object.
5121static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
5122 LValue &Result) {
5123 SubobjectDesignator &D = Result.Designator;
5124 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK: CSK_Derived))
5125 return false;
5126
5127 QualType TargetQT = E->getType();
5128 if (const PointerType *PT = TargetQT->getAs<PointerType>())
5129 TargetQT = PT->getPointeeType();
5130
5131 // Check this cast lands within the final derived-to-base subobject path.
5132 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
5133 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_downcast)
5134 << D.MostDerivedType << TargetQT;
5135 return false;
5136 }
5137
5138 // Check the type of the final cast. We don't need to check the path,
5139 // since a cast can only be formed if the path is unique.
5140 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
5141 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
5142 const CXXRecordDecl *FinalType;
5143 if (NewEntriesSize == D.MostDerivedPathLength)
5144 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
5145 else
5146 FinalType = getAsBaseClass(E: D.Entries[NewEntriesSize - 1]);
5147 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
5148 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_downcast)
5149 << D.MostDerivedType << TargetQT;
5150 return false;
5151 }
5152
5153 // Truncate the lvalue to the appropriate derived class.
5154 return CastToDerivedClass(Info, E, Result, TruncatedType: TargetType, TruncatedElements: NewEntriesSize);
5155}
5156
5157/// Get the value to use for a default-initialized object of type T.
5158/// Return false if it encounters something invalid.
5159static bool handleDefaultInitValue(QualType T, APValue &Result) {
5160 bool Success = true;
5161
5162 // If there is already a value present don't overwrite it.
5163 if (!Result.isAbsent())
5164 return true;
5165
5166 if (auto *RD = T->getAsCXXRecordDecl()) {
5167 if (RD->isInvalidDecl()) {
5168 Result = APValue();
5169 return false;
5170 }
5171 if (RD->isUnion()) {
5172 Result = APValue((const FieldDecl *)nullptr);
5173 return true;
5174 }
5175 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
5176 std::distance(first: RD->field_begin(), last: RD->field_end()));
5177
5178 unsigned Index = 0;
5179 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
5180 End = RD->bases_end();
5181 I != End; ++I, ++Index)
5182 Success &=
5183 handleDefaultInitValue(T: I->getType(), Result&: Result.getStructBase(i: Index));
5184
5185 for (const auto *I : RD->fields()) {
5186 if (I->isUnnamedBitField())
5187 continue;
5188 Success &= handleDefaultInitValue(
5189 T: I->getType(), Result&: Result.getStructField(i: I->getFieldIndex()));
5190 }
5191 return Success;
5192 }
5193
5194 if (auto *AT =
5195 dyn_cast_or_null<ConstantArrayType>(Val: T->getAsArrayTypeUnsafe())) {
5196 Result = APValue(APValue::UninitArray(), 0, AT->getZExtSize());
5197 if (Result.hasArrayFiller())
5198 Success &=
5199 handleDefaultInitValue(T: AT->getElementType(), Result&: Result.getArrayFiller());
5200
5201 return Success;
5202 }
5203
5204 Result = APValue::IndeterminateValue();
5205 return true;
5206}
5207
5208namespace {
5209enum EvalStmtResult {
5210 /// Evaluation failed.
5211 ESR_Failed,
5212 /// Hit a 'return' statement.
5213 ESR_Returned,
5214 /// Evaluation succeeded.
5215 ESR_Succeeded,
5216 /// Hit a 'continue' statement.
5217 ESR_Continue,
5218 /// Hit a 'break' statement.
5219 ESR_Break,
5220 /// Still scanning for 'case' or 'default' statement.
5221 ESR_CaseNotFound
5222};
5223}
5224
5225static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
5226 if (VD->isInvalidDecl())
5227 return false;
5228 // We don't need to evaluate the initializer for a static local.
5229 if (!VD->hasLocalStorage())
5230 return true;
5231
5232 LValue Result;
5233 APValue &Val = Info.CurrentCall->createTemporary(Key: VD, T: VD->getType(),
5234 Scope: ScopeKind::Block, LV&: Result);
5235
5236 const Expr *InitE = VD->getInit();
5237 if (!InitE) {
5238 if (VD->getType()->isDependentType())
5239 return Info.noteSideEffect();
5240 return handleDefaultInitValue(T: VD->getType(), Result&: Val);
5241 }
5242 if (InitE->isValueDependent())
5243 return false;
5244
5245 if (!EvaluateInPlace(Result&: Val, Info, This: Result, E: InitE)) {
5246 // Wipe out any partially-computed value, to allow tracking that this
5247 // evaluation failed.
5248 Val = APValue();
5249 return false;
5250 }
5251
5252 return true;
5253}
5254
5255static bool EvaluateDecompositionDeclInit(EvalInfo &Info,
5256 const DecompositionDecl *DD);
5257
5258static bool EvaluateDecl(EvalInfo &Info, const Decl *D,
5259 bool EvaluateConditionDecl = false) {
5260 bool OK = true;
5261 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
5262 OK &= EvaluateVarDecl(Info, VD);
5263
5264 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(Val: D);
5265 EvaluateConditionDecl && DD)
5266 OK &= EvaluateDecompositionDeclInit(Info, DD);
5267
5268 return OK;
5269}
5270
5271static bool EvaluateDecompositionDeclInit(EvalInfo &Info,
5272 const DecompositionDecl *DD) {
5273 bool OK = true;
5274 for (auto *BD : DD->flat_bindings())
5275 if (auto *VD = BD->getHoldingVar())
5276 OK &= EvaluateDecl(Info, D: VD, /*EvaluateConditionDecl=*/true);
5277
5278 return OK;
5279}
5280
5281static bool MaybeEvaluateDeferredVarDeclInit(EvalInfo &Info,
5282 const VarDecl *VD) {
5283 if (auto *DD = dyn_cast_if_present<DecompositionDecl>(Val: VD)) {
5284 if (!EvaluateDecompositionDeclInit(Info, DD))
5285 return false;
5286 }
5287 return true;
5288}
5289
5290static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) {
5291 assert(E->isValueDependent());
5292 if (Info.noteSideEffect())
5293 return true;
5294 assert(E->containsErrors() && "valid value-dependent expression should never "
5295 "reach invalid code path.");
5296 return false;
5297}
5298
5299/// Evaluate a condition (either a variable declaration or an expression).
5300static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
5301 const Expr *Cond, bool &Result) {
5302 if (Cond->isValueDependent())
5303 return false;
5304 FullExpressionRAII Scope(Info);
5305 if (CondDecl && !EvaluateDecl(Info, D: CondDecl))
5306 return false;
5307 if (!EvaluateAsBooleanCondition(E: Cond, Result, Info))
5308 return false;
5309 if (!MaybeEvaluateDeferredVarDeclInit(Info, VD: CondDecl))
5310 return false;
5311 return Scope.destroy();
5312}
5313
5314namespace {
5315/// A location where the result (returned value) of evaluating a
5316/// statement should be stored.
5317struct StmtResult {
5318 /// The APValue that should be filled in with the returned value.
5319 APValue &Value;
5320 /// The location containing the result, if any (used to support RVO).
5321 const LValue *Slot;
5322};
5323
5324struct TempVersionRAII {
5325 CallStackFrame &Frame;
5326
5327 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
5328 Frame.pushTempVersion();
5329 }
5330
5331 ~TempVersionRAII() {
5332 Frame.popTempVersion();
5333 }
5334};
5335
5336}
5337
5338static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
5339 const Stmt *S,
5340 const SwitchCase *SC = nullptr);
5341
5342/// Evaluate the body of a loop, and translate the result as appropriate.
5343static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
5344 const Stmt *Body,
5345 const SwitchCase *Case = nullptr) {
5346 BlockScopeRAII Scope(Info);
5347
5348 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Body, SC: Case);
5349 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
5350 ESR = ESR_Failed;
5351
5352 switch (ESR) {
5353 case ESR_Break:
5354 return ESR_Succeeded;
5355 case ESR_Succeeded:
5356 case ESR_Continue:
5357 return ESR_Continue;
5358 case ESR_Failed:
5359 case ESR_Returned:
5360 case ESR_CaseNotFound:
5361 return ESR;
5362 }
5363 llvm_unreachable("Invalid EvalStmtResult!");
5364}
5365
5366/// Evaluate a switch statement.
5367static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
5368 const SwitchStmt *SS) {
5369 BlockScopeRAII Scope(Info);
5370
5371 // Evaluate the switch condition.
5372 APSInt Value;
5373 {
5374 if (const Stmt *Init = SS->getInit()) {
5375 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init);
5376 if (ESR != ESR_Succeeded) {
5377 if (ESR != ESR_Failed && !Scope.destroy())
5378 ESR = ESR_Failed;
5379 return ESR;
5380 }
5381 }
5382
5383 FullExpressionRAII CondScope(Info);
5384 if (SS->getConditionVariable() &&
5385 !EvaluateDecl(Info, D: SS->getConditionVariable()))
5386 return ESR_Failed;
5387 if (SS->getCond()->isValueDependent()) {
5388 // We don't know what the value is, and which branch should jump to.
5389 EvaluateDependentExpr(E: SS->getCond(), Info);
5390 return ESR_Failed;
5391 }
5392 if (!EvaluateInteger(E: SS->getCond(), Result&: Value, Info))
5393 return ESR_Failed;
5394
5395 if (!MaybeEvaluateDeferredVarDeclInit(Info, VD: SS->getConditionVariable()))
5396 return ESR_Failed;
5397
5398 if (!CondScope.destroy())
5399 return ESR_Failed;
5400 }
5401
5402 // Find the switch case corresponding to the value of the condition.
5403 // FIXME: Cache this lookup.
5404 const SwitchCase *Found = nullptr;
5405 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
5406 SC = SC->getNextSwitchCase()) {
5407 if (isa<DefaultStmt>(Val: SC)) {
5408 Found = SC;
5409 continue;
5410 }
5411
5412 const CaseStmt *CS = cast<CaseStmt>(Val: SC);
5413 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Ctx: Info.Ctx);
5414 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Ctx: Info.Ctx)
5415 : LHS;
5416 if (LHS <= Value && Value <= RHS) {
5417 Found = SC;
5418 break;
5419 }
5420 }
5421
5422 if (!Found)
5423 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5424
5425 // Search the switch body for the switch case and evaluate it from there.
5426 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: SS->getBody(), SC: Found);
5427 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
5428 return ESR_Failed;
5429
5430 switch (ESR) {
5431 case ESR_Break:
5432 return ESR_Succeeded;
5433 case ESR_Succeeded:
5434 case ESR_Continue:
5435 case ESR_Failed:
5436 case ESR_Returned:
5437 return ESR;
5438 case ESR_CaseNotFound:
5439 // This can only happen if the switch case is nested within a statement
5440 // expression. We have no intention of supporting that.
5441 Info.FFDiag(Loc: Found->getBeginLoc(),
5442 DiagId: diag::note_constexpr_stmt_expr_unsupported);
5443 return ESR_Failed;
5444 }
5445 llvm_unreachable("Invalid EvalStmtResult!");
5446}
5447
5448static bool CheckLocalVariableDeclaration(EvalInfo &Info, const VarDecl *VD) {
5449 // An expression E is a core constant expression unless the evaluation of E
5450 // would evaluate one of the following: [C++23] - a control flow that passes
5451 // through a declaration of a variable with static or thread storage duration
5452 // unless that variable is usable in constant expressions.
5453 if (VD->isLocalVarDecl() && VD->isStaticLocal() &&
5454 !VD->isUsableInConstantExpressions(C: Info.Ctx)) {
5455 Info.CCEDiag(Loc: VD->getLocation(), DiagId: diag::note_constexpr_static_local)
5456 << (VD->getTSCSpec() == TSCS_unspecified ? 0 : 1) << VD;
5457 return false;
5458 }
5459 return true;
5460}
5461
5462// Evaluate a statement.
5463static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
5464 const Stmt *S, const SwitchCase *Case) {
5465 if (!Info.nextStep(S))
5466 return ESR_Failed;
5467
5468 // If we're hunting down a 'case' or 'default' label, recurse through
5469 // substatements until we hit the label.
5470 if (Case) {
5471 switch (S->getStmtClass()) {
5472 case Stmt::CompoundStmtClass:
5473 // FIXME: Precompute which substatement of a compound statement we
5474 // would jump to, and go straight there rather than performing a
5475 // linear scan each time.
5476 case Stmt::LabelStmtClass:
5477 case Stmt::AttributedStmtClass:
5478 case Stmt::DoStmtClass:
5479 break;
5480
5481 case Stmt::CaseStmtClass:
5482 case Stmt::DefaultStmtClass:
5483 if (Case == S)
5484 Case = nullptr;
5485 break;
5486
5487 case Stmt::IfStmtClass: {
5488 // FIXME: Precompute which side of an 'if' we would jump to, and go
5489 // straight there rather than scanning both sides.
5490 const IfStmt *IS = cast<IfStmt>(Val: S);
5491
5492 // Wrap the evaluation in a block scope, in case it's a DeclStmt
5493 // preceded by our switch label.
5494 BlockScopeRAII Scope(Info);
5495
5496 // Step into the init statement in case it brings an (uninitialized)
5497 // variable into scope.
5498 if (const Stmt *Init = IS->getInit()) {
5499 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init, Case);
5500 if (ESR != ESR_CaseNotFound) {
5501 assert(ESR != ESR_Succeeded);
5502 return ESR;
5503 }
5504 }
5505
5506 // Condition variable must be initialized if it exists.
5507 // FIXME: We can skip evaluating the body if there's a condition
5508 // variable, as there can't be any case labels within it.
5509 // (The same is true for 'for' statements.)
5510
5511 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: IS->getThen(), Case);
5512 if (ESR == ESR_Failed)
5513 return ESR;
5514 if (ESR != ESR_CaseNotFound)
5515 return Scope.destroy() ? ESR : ESR_Failed;
5516 if (!IS->getElse())
5517 return ESR_CaseNotFound;
5518
5519 ESR = EvaluateStmt(Result, Info, S: IS->getElse(), Case);
5520 if (ESR == ESR_Failed)
5521 return ESR;
5522 if (ESR != ESR_CaseNotFound)
5523 return Scope.destroy() ? ESR : ESR_Failed;
5524 return ESR_CaseNotFound;
5525 }
5526
5527 case Stmt::WhileStmtClass: {
5528 EvalStmtResult ESR =
5529 EvaluateLoopBody(Result, Info, Body: cast<WhileStmt>(Val: S)->getBody(), Case);
5530 if (ESR != ESR_Continue)
5531 return ESR;
5532 break;
5533 }
5534
5535 case Stmt::ForStmtClass: {
5536 const ForStmt *FS = cast<ForStmt>(Val: S);
5537 BlockScopeRAII Scope(Info);
5538
5539 // Step into the init statement in case it brings an (uninitialized)
5540 // variable into scope.
5541 if (const Stmt *Init = FS->getInit()) {
5542 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init, Case);
5543 if (ESR != ESR_CaseNotFound) {
5544 assert(ESR != ESR_Succeeded);
5545 return ESR;
5546 }
5547 }
5548
5549 EvalStmtResult ESR =
5550 EvaluateLoopBody(Result, Info, Body: FS->getBody(), Case);
5551 if (ESR != ESR_Continue)
5552 return ESR;
5553 if (const auto *Inc = FS->getInc()) {
5554 if (Inc->isValueDependent()) {
5555 if (!EvaluateDependentExpr(E: Inc, Info))
5556 return ESR_Failed;
5557 } else {
5558 FullExpressionRAII IncScope(Info);
5559 if (!EvaluateIgnoredValue(Info, E: Inc) || !IncScope.destroy())
5560 return ESR_Failed;
5561 }
5562 }
5563 break;
5564 }
5565
5566 case Stmt::DeclStmtClass: {
5567 // Start the lifetime of any uninitialized variables we encounter. They
5568 // might be used by the selected branch of the switch.
5569 const DeclStmt *DS = cast<DeclStmt>(Val: S);
5570 for (const auto *D : DS->decls()) {
5571 if (const auto *VD = dyn_cast<VarDecl>(Val: D)) {
5572 if (!CheckLocalVariableDeclaration(Info, VD))
5573 return ESR_Failed;
5574 if (VD->hasLocalStorage() && !VD->getInit())
5575 if (!EvaluateVarDecl(Info, VD))
5576 return ESR_Failed;
5577 // FIXME: If the variable has initialization that can't be jumped
5578 // over, bail out of any immediately-surrounding compound-statement
5579 // too. There can't be any case labels here.
5580 }
5581 }
5582 return ESR_CaseNotFound;
5583 }
5584
5585 default:
5586 return ESR_CaseNotFound;
5587 }
5588 }
5589
5590 switch (S->getStmtClass()) {
5591 default:
5592 if (const Expr *E = dyn_cast<Expr>(Val: S)) {
5593 if (E->isValueDependent()) {
5594 if (!EvaluateDependentExpr(E, Info))
5595 return ESR_Failed;
5596 } else {
5597 // Don't bother evaluating beyond an expression-statement which couldn't
5598 // be evaluated.
5599 // FIXME: Do we need the FullExpressionRAII object here?
5600 // VisitExprWithCleanups should create one when necessary.
5601 FullExpressionRAII Scope(Info);
5602 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
5603 return ESR_Failed;
5604 }
5605 return ESR_Succeeded;
5606 }
5607
5608 Info.FFDiag(Loc: S->getBeginLoc()) << S->getSourceRange();
5609 return ESR_Failed;
5610
5611 case Stmt::NullStmtClass:
5612 return ESR_Succeeded;
5613
5614 case Stmt::DeclStmtClass: {
5615 const DeclStmt *DS = cast<DeclStmt>(Val: S);
5616 for (const auto *D : DS->decls()) {
5617 const VarDecl *VD = dyn_cast_or_null<VarDecl>(Val: D);
5618 if (VD && !CheckLocalVariableDeclaration(Info, VD))
5619 return ESR_Failed;
5620 // Each declaration initialization is its own full-expression.
5621 FullExpressionRAII Scope(Info);
5622 if (!EvaluateDecl(Info, D, /*EvaluateConditionDecl=*/true) &&
5623 !Info.noteFailure())
5624 return ESR_Failed;
5625 if (!Scope.destroy())
5626 return ESR_Failed;
5627 }
5628 return ESR_Succeeded;
5629 }
5630
5631 case Stmt::ReturnStmtClass: {
5632 const Expr *RetExpr = cast<ReturnStmt>(Val: S)->getRetValue();
5633 FullExpressionRAII Scope(Info);
5634 if (RetExpr && RetExpr->isValueDependent()) {
5635 EvaluateDependentExpr(E: RetExpr, Info);
5636 // We know we returned, but we don't know what the value is.
5637 return ESR_Failed;
5638 }
5639 if (RetExpr &&
5640 !(Result.Slot
5641 ? EvaluateInPlace(Result&: Result.Value, Info, This: *Result.Slot, E: RetExpr)
5642 : Evaluate(Result&: Result.Value, Info, E: RetExpr)))
5643 return ESR_Failed;
5644 return Scope.destroy() ? ESR_Returned : ESR_Failed;
5645 }
5646
5647 case Stmt::CompoundStmtClass: {
5648 BlockScopeRAII Scope(Info);
5649
5650 const CompoundStmt *CS = cast<CompoundStmt>(Val: S);
5651 for (const auto *BI : CS->body()) {
5652 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: BI, Case);
5653 if (ESR == ESR_Succeeded)
5654 Case = nullptr;
5655 else if (ESR != ESR_CaseNotFound) {
5656 if (ESR != ESR_Failed && !Scope.destroy())
5657 return ESR_Failed;
5658 return ESR;
5659 }
5660 }
5661 if (Case)
5662 return ESR_CaseNotFound;
5663 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5664 }
5665
5666 case Stmt::IfStmtClass: {
5667 const IfStmt *IS = cast<IfStmt>(Val: S);
5668
5669 // Evaluate the condition, as either a var decl or as an expression.
5670 BlockScopeRAII Scope(Info);
5671 if (const Stmt *Init = IS->getInit()) {
5672 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init);
5673 if (ESR != ESR_Succeeded) {
5674 if (ESR != ESR_Failed && !Scope.destroy())
5675 return ESR_Failed;
5676 return ESR;
5677 }
5678 }
5679 bool Cond;
5680 if (IS->isConsteval()) {
5681 Cond = IS->isNonNegatedConsteval();
5682 // If we are not in a constant context, if consteval should not evaluate
5683 // to true.
5684 if (!Info.InConstantContext)
5685 Cond = !Cond;
5686 } else if (!EvaluateCond(Info, CondDecl: IS->getConditionVariable(), Cond: IS->getCond(),
5687 Result&: Cond))
5688 return ESR_Failed;
5689
5690 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
5691 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: SubStmt);
5692 if (ESR != ESR_Succeeded) {
5693 if (ESR != ESR_Failed && !Scope.destroy())
5694 return ESR_Failed;
5695 return ESR;
5696 }
5697 }
5698 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5699 }
5700
5701 case Stmt::WhileStmtClass: {
5702 const WhileStmt *WS = cast<WhileStmt>(Val: S);
5703 while (true) {
5704 BlockScopeRAII Scope(Info);
5705 bool Continue;
5706 if (!EvaluateCond(Info, CondDecl: WS->getConditionVariable(), Cond: WS->getCond(),
5707 Result&: Continue))
5708 return ESR_Failed;
5709 if (!Continue)
5710 break;
5711
5712 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: WS->getBody());
5713 if (ESR != ESR_Continue) {
5714 if (ESR != ESR_Failed && !Scope.destroy())
5715 return ESR_Failed;
5716 return ESR;
5717 }
5718 if (!Scope.destroy())
5719 return ESR_Failed;
5720 }
5721 return ESR_Succeeded;
5722 }
5723
5724 case Stmt::DoStmtClass: {
5725 const DoStmt *DS = cast<DoStmt>(Val: S);
5726 bool Continue;
5727 do {
5728 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: DS->getBody(), Case);
5729 if (ESR != ESR_Continue)
5730 return ESR;
5731 Case = nullptr;
5732
5733 if (DS->getCond()->isValueDependent()) {
5734 EvaluateDependentExpr(E: DS->getCond(), Info);
5735 // Bailout as we don't know whether to keep going or terminate the loop.
5736 return ESR_Failed;
5737 }
5738 FullExpressionRAII CondScope(Info);
5739 if (!EvaluateAsBooleanCondition(E: DS->getCond(), Result&: Continue, Info) ||
5740 !CondScope.destroy())
5741 return ESR_Failed;
5742 } while (Continue);
5743 return ESR_Succeeded;
5744 }
5745
5746 case Stmt::ForStmtClass: {
5747 const ForStmt *FS = cast<ForStmt>(Val: S);
5748 BlockScopeRAII ForScope(Info);
5749 if (FS->getInit()) {
5750 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getInit());
5751 if (ESR != ESR_Succeeded) {
5752 if (ESR != ESR_Failed && !ForScope.destroy())
5753 return ESR_Failed;
5754 return ESR;
5755 }
5756 }
5757 while (true) {
5758 BlockScopeRAII IterScope(Info);
5759 bool Continue = true;
5760 if (FS->getCond() && !EvaluateCond(Info, CondDecl: FS->getConditionVariable(),
5761 Cond: FS->getCond(), Result&: Continue))
5762 return ESR_Failed;
5763
5764 if (!Continue) {
5765 if (!IterScope.destroy())
5766 return ESR_Failed;
5767 break;
5768 }
5769
5770 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: FS->getBody());
5771 if (ESR != ESR_Continue) {
5772 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
5773 return ESR_Failed;
5774 return ESR;
5775 }
5776
5777 if (const auto *Inc = FS->getInc()) {
5778 if (Inc->isValueDependent()) {
5779 if (!EvaluateDependentExpr(E: Inc, Info))
5780 return ESR_Failed;
5781 } else {
5782 FullExpressionRAII IncScope(Info);
5783 if (!EvaluateIgnoredValue(Info, E: Inc) || !IncScope.destroy())
5784 return ESR_Failed;
5785 }
5786 }
5787
5788 if (!IterScope.destroy())
5789 return ESR_Failed;
5790 }
5791 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
5792 }
5793
5794 case Stmt::CXXForRangeStmtClass: {
5795 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(Val: S);
5796 BlockScopeRAII Scope(Info);
5797
5798 // Evaluate the init-statement if present.
5799 if (FS->getInit()) {
5800 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getInit());
5801 if (ESR != ESR_Succeeded) {
5802 if (ESR != ESR_Failed && !Scope.destroy())
5803 return ESR_Failed;
5804 return ESR;
5805 }
5806 }
5807
5808 // Initialize the __range variable.
5809 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getRangeStmt());
5810 if (ESR != ESR_Succeeded) {
5811 if (ESR != ESR_Failed && !Scope.destroy())
5812 return ESR_Failed;
5813 return ESR;
5814 }
5815
5816 // In error-recovery cases it's possible to get here even if we failed to
5817 // synthesize the __begin and __end variables.
5818 if (!FS->getBeginStmt() || !FS->getEndStmt() || !FS->getCond())
5819 return ESR_Failed;
5820
5821 // Create the __begin and __end iterators.
5822 ESR = EvaluateStmt(Result, Info, S: FS->getBeginStmt());
5823 if (ESR != ESR_Succeeded) {
5824 if (ESR != ESR_Failed && !Scope.destroy())
5825 return ESR_Failed;
5826 return ESR;
5827 }
5828 ESR = EvaluateStmt(Result, Info, S: FS->getEndStmt());
5829 if (ESR != ESR_Succeeded) {
5830 if (ESR != ESR_Failed && !Scope.destroy())
5831 return ESR_Failed;
5832 return ESR;
5833 }
5834
5835 while (true) {
5836 // Condition: __begin != __end.
5837 {
5838 if (FS->getCond()->isValueDependent()) {
5839 EvaluateDependentExpr(E: FS->getCond(), Info);
5840 // We don't know whether to keep going or terminate the loop.
5841 return ESR_Failed;
5842 }
5843 bool Continue = true;
5844 FullExpressionRAII CondExpr(Info);
5845 if (!EvaluateAsBooleanCondition(E: FS->getCond(), Result&: Continue, Info))
5846 return ESR_Failed;
5847 if (!Continue)
5848 break;
5849 }
5850
5851 // User's variable declaration, initialized by *__begin.
5852 BlockScopeRAII InnerScope(Info);
5853 ESR = EvaluateStmt(Result, Info, S: FS->getLoopVarStmt());
5854 if (ESR != ESR_Succeeded) {
5855 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5856 return ESR_Failed;
5857 return ESR;
5858 }
5859
5860 // Loop body.
5861 ESR = EvaluateLoopBody(Result, Info, Body: FS->getBody());
5862 if (ESR != ESR_Continue) {
5863 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5864 return ESR_Failed;
5865 return ESR;
5866 }
5867 if (FS->getInc()->isValueDependent()) {
5868 if (!EvaluateDependentExpr(E: FS->getInc(), Info))
5869 return ESR_Failed;
5870 } else {
5871 // Increment: ++__begin
5872 if (!EvaluateIgnoredValue(Info, E: FS->getInc()))
5873 return ESR_Failed;
5874 }
5875
5876 if (!InnerScope.destroy())
5877 return ESR_Failed;
5878 }
5879
5880 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5881 }
5882
5883 case Stmt::SwitchStmtClass:
5884 return EvaluateSwitch(Result, Info, SS: cast<SwitchStmt>(Val: S));
5885
5886 case Stmt::ContinueStmtClass:
5887 return ESR_Continue;
5888
5889 case Stmt::BreakStmtClass:
5890 return ESR_Break;
5891
5892 case Stmt::LabelStmtClass:
5893 return EvaluateStmt(Result, Info, S: cast<LabelStmt>(Val: S)->getSubStmt(), Case);
5894
5895 case Stmt::AttributedStmtClass: {
5896 const auto *AS = cast<AttributedStmt>(Val: S);
5897 const auto *SS = AS->getSubStmt();
5898 MSConstexprContextRAII ConstexprContext(
5899 *Info.CurrentCall, hasSpecificAttr<MSConstexprAttr>(container: AS->getAttrs()) &&
5900 isa<ReturnStmt>(Val: SS));
5901
5902 auto LO = Info.getASTContext().getLangOpts();
5903 if (LO.CXXAssumptions && !LO.MSVCCompat) {
5904 for (auto *Attr : AS->getAttrs()) {
5905 auto *AA = dyn_cast<CXXAssumeAttr>(Val: Attr);
5906 if (!AA)
5907 continue;
5908
5909 auto *Assumption = AA->getAssumption();
5910 if (Assumption->isValueDependent())
5911 return ESR_Failed;
5912
5913 if (Assumption->HasSideEffects(Ctx: Info.getASTContext()))
5914 continue;
5915
5916 bool Value;
5917 if (!EvaluateAsBooleanCondition(E: Assumption, Result&: Value, Info))
5918 return ESR_Failed;
5919 if (!Value) {
5920 Info.CCEDiag(Loc: Assumption->getExprLoc(),
5921 DiagId: diag::note_constexpr_assumption_failed);
5922 return ESR_Failed;
5923 }
5924 }
5925 }
5926
5927 return EvaluateStmt(Result, Info, S: SS, Case);
5928 }
5929
5930 case Stmt::CaseStmtClass:
5931 case Stmt::DefaultStmtClass:
5932 return EvaluateStmt(Result, Info, S: cast<SwitchCase>(Val: S)->getSubStmt(), Case);
5933 case Stmt::CXXTryStmtClass:
5934 // Evaluate try blocks by evaluating all sub statements.
5935 return EvaluateStmt(Result, Info, S: cast<CXXTryStmt>(Val: S)->getTryBlock(), Case);
5936 }
5937}
5938
5939/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5940/// default constructor. If so, we'll fold it whether or not it's marked as
5941/// constexpr. If it is marked as constexpr, we will never implicitly define it,
5942/// so we need special handling.
5943static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
5944 const CXXConstructorDecl *CD,
5945 bool IsValueInitialization) {
5946 if (!CD->isTrivial() || !CD->isDefaultConstructor())
5947 return false;
5948
5949 // Value-initialization does not call a trivial default constructor, so such a
5950 // call is a core constant expression whether or not the constructor is
5951 // constexpr.
5952 if (!CD->isConstexpr() && !IsValueInitialization) {
5953 if (Info.getLangOpts().CPlusPlus11) {
5954 // FIXME: If DiagDecl is an implicitly-declared special member function,
5955 // we should be much more explicit about why it's not constexpr.
5956 Info.CCEDiag(Loc, DiagId: diag::note_constexpr_invalid_function, ExtraNotes: 1)
5957 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
5958 Info.Note(Loc: CD->getLocation(), DiagId: diag::note_declared_at);
5959 } else {
5960 Info.CCEDiag(Loc, DiagId: diag::note_invalid_subexpr_in_const_expr);
5961 }
5962 }
5963 return true;
5964}
5965
5966/// CheckConstexprFunction - Check that a function can be called in a constant
5967/// expression.
5968static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
5969 const FunctionDecl *Declaration,
5970 const FunctionDecl *Definition,
5971 const Stmt *Body) {
5972 // Potential constant expressions can contain calls to declared, but not yet
5973 // defined, constexpr functions.
5974 if (Info.checkingPotentialConstantExpression() && !Definition &&
5975 Declaration->isConstexpr())
5976 return false;
5977
5978 // Bail out if the function declaration itself is invalid. We will
5979 // have produced a relevant diagnostic while parsing it, so just
5980 // note the problematic sub-expression.
5981 if (Declaration->isInvalidDecl()) {
5982 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_invalid_subexpr_in_const_expr);
5983 return false;
5984 }
5985
5986 // DR1872: An instantiated virtual constexpr function can't be called in a
5987 // constant expression (prior to C++20). We can still constant-fold such a
5988 // call.
5989 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Val: Declaration) &&
5990 cast<CXXMethodDecl>(Val: Declaration)->isVirtual())
5991 Info.CCEDiag(Loc: CallLoc, DiagId: diag::note_constexpr_virtual_call);
5992
5993 if (Definition && Definition->isInvalidDecl()) {
5994 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_invalid_subexpr_in_const_expr);
5995 return false;
5996 }
5997
5998 // Can we evaluate this function call?
5999 if (Definition && Body &&
6000 (Definition->isConstexpr() || (Info.CurrentCall->CanEvalMSConstexpr &&
6001 Definition->hasAttr<MSConstexprAttr>())))
6002 return true;
6003
6004 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
6005 // Special note for the assert() macro, as the normal error message falsely
6006 // implies we cannot use an assertion during constant evaluation.
6007 if (CallLoc.isMacroID() && DiagDecl->getIdentifier()) {
6008 // FIXME: Instead of checking for an implementation-defined function,
6009 // check and evaluate the assert() macro.
6010 StringRef Name = DiagDecl->getName();
6011 bool AssertFailed =
6012 Name == "__assert_rtn" || Name == "__assert_fail" || Name == "_wassert";
6013 if (AssertFailed) {
6014 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_constexpr_assert_failed);
6015 return false;
6016 }
6017 }
6018
6019 if (Info.getLangOpts().CPlusPlus11) {
6020 // If this function is not constexpr because it is an inherited
6021 // non-constexpr constructor, diagnose that directly.
6022 auto *CD = dyn_cast<CXXConstructorDecl>(Val: DiagDecl);
6023 if (CD && CD->isInheritingConstructor()) {
6024 auto *Inherited = CD->getInheritedConstructor().getConstructor();
6025 if (!Inherited->isConstexpr())
6026 DiagDecl = CD = Inherited;
6027 }
6028
6029 // FIXME: If DiagDecl is an implicitly-declared special member function
6030 // or an inheriting constructor, we should be much more explicit about why
6031 // it's not constexpr.
6032 if (CD && CD->isInheritingConstructor())
6033 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_constexpr_invalid_inhctor, ExtraNotes: 1)
6034 << CD->getInheritedConstructor().getConstructor()->getParent();
6035 else
6036 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_constexpr_invalid_function, ExtraNotes: 1)
6037 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
6038 Info.Note(Loc: DiagDecl->getLocation(), DiagId: diag::note_declared_at);
6039 } else {
6040 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_invalid_subexpr_in_const_expr);
6041 }
6042 return false;
6043}
6044
6045namespace {
6046struct CheckDynamicTypeHandler {
6047 AccessKinds AccessKind;
6048 typedef bool result_type;
6049 bool failed() { return false; }
6050 bool found(APValue &Subobj, QualType SubobjType) { return true; }
6051 bool found(APSInt &Value, QualType SubobjType) { return true; }
6052 bool found(APFloat &Value, QualType SubobjType) { return true; }
6053};
6054} // end anonymous namespace
6055
6056/// Check that we can access the notional vptr of an object / determine its
6057/// dynamic type.
6058static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
6059 AccessKinds AK, bool Polymorphic) {
6060 // We are not allowed to invoke a virtual function whose dynamic type
6061 // is constexpr-unknown, so stop early and let this fail later on if we
6062 // attempt to do so.
6063 // C++23 [expr.const]p5.6
6064 // an invocation of a virtual function ([class.virtual]) for an object whose
6065 // dynamic type is constexpr-unknown;
6066 if (This.allowConstexprUnknown())
6067 return true;
6068
6069 if (This.Designator.Invalid)
6070 return false;
6071
6072 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal: This, LValType: QualType());
6073
6074 if (!Obj)
6075 return false;
6076
6077 if (!Obj.Value) {
6078 // The object is not usable in constant expressions, so we can't inspect
6079 // its value to see if it's in-lifetime or what the active union members
6080 // are. We can still check for a one-past-the-end lvalue.
6081 if (This.Designator.isOnePastTheEnd() ||
6082 This.Designator.isMostDerivedAnUnsizedArray()) {
6083 Info.FFDiag(E, DiagId: This.Designator.isOnePastTheEnd()
6084 ? diag::note_constexpr_access_past_end
6085 : diag::note_constexpr_access_unsized_array)
6086 << AK;
6087 return false;
6088 } else if (Polymorphic) {
6089 // Conservatively refuse to perform a polymorphic operation if we would
6090 // not be able to read a notional 'vptr' value.
6091 APValue Val;
6092 This.moveInto(V&: Val);
6093 QualType StarThisType =
6094 Info.Ctx.getLValueReferenceType(T: This.Designator.getType(Ctx&: Info.Ctx));
6095 Info.FFDiag(E, DiagId: diag::note_constexpr_polymorphic_unknown_dynamic_type)
6096 << AK << Val.getAsString(Ctx: Info.Ctx, Ty: StarThisType);
6097 return false;
6098 }
6099 return true;
6100 }
6101
6102 CheckDynamicTypeHandler Handler{.AccessKind: AK};
6103 return Obj && findSubobject(Info, E, Obj, Sub: This.Designator, handler&: Handler);
6104}
6105
6106/// Check that the pointee of the 'this' pointer in a member function call is
6107/// either within its lifetime or in its period of construction or destruction.
6108static bool
6109checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
6110 const LValue &This,
6111 const CXXMethodDecl *NamedMember) {
6112 return checkDynamicType(
6113 Info, E, This,
6114 AK: isa<CXXDestructorDecl>(Val: NamedMember) ? AK_Destroy : AK_MemberCall, Polymorphic: false);
6115}
6116
6117struct DynamicType {
6118 /// The dynamic class type of the object.
6119 const CXXRecordDecl *Type;
6120 /// The corresponding path length in the lvalue.
6121 unsigned PathLength;
6122};
6123
6124static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
6125 unsigned PathLength) {
6126 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=
6127 Designator.Entries.size() && "invalid path length");
6128 return (PathLength == Designator.MostDerivedPathLength)
6129 ? Designator.MostDerivedType->getAsCXXRecordDecl()
6130 : getAsBaseClass(E: Designator.Entries[PathLength - 1]);
6131}
6132
6133/// Determine the dynamic type of an object.
6134static std::optional<DynamicType> ComputeDynamicType(EvalInfo &Info,
6135 const Expr *E,
6136 LValue &This,
6137 AccessKinds AK) {
6138 // If we don't have an lvalue denoting an object of class type, there is no
6139 // meaningful dynamic type. (We consider objects of non-class type to have no
6140 // dynamic type.)
6141 if (!checkDynamicType(Info, E, This, AK,
6142 Polymorphic: (AK == AK_TypeId
6143 ? (E->getType()->isReferenceType() ? true : false)
6144 : true)))
6145 return std::nullopt;
6146
6147 if (This.Designator.Invalid)
6148 return std::nullopt;
6149
6150 // Refuse to compute a dynamic type in the presence of virtual bases. This
6151 // shouldn't happen other than in constant-folding situations, since literal
6152 // types can't have virtual bases.
6153 //
6154 // Note that consumers of DynamicType assume that the type has no virtual
6155 // bases, and will need modifications if this restriction is relaxed.
6156 const CXXRecordDecl *Class =
6157 This.Designator.MostDerivedType->getAsCXXRecordDecl();
6158 if (!Class || Class->getNumVBases()) {
6159 Info.FFDiag(E);
6160 return std::nullopt;
6161 }
6162
6163 // FIXME: For very deep class hierarchies, it might be beneficial to use a
6164 // binary search here instead. But the overwhelmingly common case is that
6165 // we're not in the middle of a constructor, so it probably doesn't matter
6166 // in practice.
6167 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
6168 for (unsigned PathLength = This.Designator.MostDerivedPathLength;
6169 PathLength <= Path.size(); ++PathLength) {
6170 switch (Info.isEvaluatingCtorDtor(Base: This.getLValueBase(),
6171 Path: Path.slice(N: 0, M: PathLength))) {
6172 case ConstructionPhase::Bases:
6173 case ConstructionPhase::DestroyingBases:
6174 // We're constructing or destroying a base class. This is not the dynamic
6175 // type.
6176 break;
6177
6178 case ConstructionPhase::None:
6179 case ConstructionPhase::AfterBases:
6180 case ConstructionPhase::AfterFields:
6181 case ConstructionPhase::Destroying:
6182 // We've finished constructing the base classes and not yet started
6183 // destroying them again, so this is the dynamic type.
6184 return DynamicType{.Type: getBaseClassType(Designator&: This.Designator, PathLength),
6185 .PathLength: PathLength};
6186 }
6187 }
6188
6189 // CWG issue 1517: we're constructing a base class of the object described by
6190 // 'This', so that object has not yet begun its period of construction and
6191 // any polymorphic operation on it results in undefined behavior.
6192 Info.FFDiag(E);
6193 return std::nullopt;
6194}
6195
6196/// Perform virtual dispatch.
6197static const CXXMethodDecl *HandleVirtualDispatch(
6198 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
6199 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
6200 std::optional<DynamicType> DynType = ComputeDynamicType(
6201 Info, E, This,
6202 AK: isa<CXXDestructorDecl>(Val: Found) ? AK_Destroy : AK_MemberCall);
6203 if (!DynType)
6204 return nullptr;
6205
6206 // Find the final overrider. It must be declared in one of the classes on the
6207 // path from the dynamic type to the static type.
6208 // FIXME: If we ever allow literal types to have virtual base classes, that
6209 // won't be true.
6210 const CXXMethodDecl *Callee = Found;
6211 unsigned PathLength = DynType->PathLength;
6212 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
6213 const CXXRecordDecl *Class = getBaseClassType(Designator&: This.Designator, PathLength);
6214 const CXXMethodDecl *Overrider =
6215 Found->getCorrespondingMethodDeclaredInClass(RD: Class, MayBeBase: false);
6216 if (Overrider) {
6217 Callee = Overrider;
6218 break;
6219 }
6220 }
6221
6222 // C++2a [class.abstract]p6:
6223 // the effect of making a virtual call to a pure virtual function [...] is
6224 // undefined
6225 if (Callee->isPureVirtual()) {
6226 Info.FFDiag(E, DiagId: diag::note_constexpr_pure_virtual_call, ExtraNotes: 1) << Callee;
6227 Info.Note(Loc: Callee->getLocation(), DiagId: diag::note_declared_at);
6228 return nullptr;
6229 }
6230
6231 // If necessary, walk the rest of the path to determine the sequence of
6232 // covariant adjustment steps to apply.
6233 if (!Info.Ctx.hasSameUnqualifiedType(T1: Callee->getReturnType(),
6234 T2: Found->getReturnType())) {
6235 CovariantAdjustmentPath.push_back(Elt: Callee->getReturnType());
6236 for (unsigned CovariantPathLength = PathLength + 1;
6237 CovariantPathLength != This.Designator.Entries.size();
6238 ++CovariantPathLength) {
6239 const CXXRecordDecl *NextClass =
6240 getBaseClassType(Designator&: This.Designator, PathLength: CovariantPathLength);
6241 const CXXMethodDecl *Next =
6242 Found->getCorrespondingMethodDeclaredInClass(RD: NextClass, MayBeBase: false);
6243 if (Next && !Info.Ctx.hasSameUnqualifiedType(
6244 T1: Next->getReturnType(), T2: CovariantAdjustmentPath.back()))
6245 CovariantAdjustmentPath.push_back(Elt: Next->getReturnType());
6246 }
6247 if (!Info.Ctx.hasSameUnqualifiedType(T1: Found->getReturnType(),
6248 T2: CovariantAdjustmentPath.back()))
6249 CovariantAdjustmentPath.push_back(Elt: Found->getReturnType());
6250 }
6251
6252 // Perform 'this' adjustment.
6253 if (!CastToDerivedClass(Info, E, Result&: This, TruncatedType: Callee->getParent(), TruncatedElements: PathLength))
6254 return nullptr;
6255
6256 return Callee;
6257}
6258
6259/// Perform the adjustment from a value returned by a virtual function to
6260/// a value of the statically expected type, which may be a pointer or
6261/// reference to a base class of the returned type.
6262static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
6263 APValue &Result,
6264 ArrayRef<QualType> Path) {
6265 assert(Result.isLValue() &&
6266 "unexpected kind of APValue for covariant return");
6267 if (Result.isNullPointer())
6268 return true;
6269
6270 LValue LVal;
6271 LVal.setFrom(Ctx&: Info.Ctx, V: Result);
6272
6273 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
6274 for (unsigned I = 1; I != Path.size(); ++I) {
6275 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
6276 assert(OldClass && NewClass && "unexpected kind of covariant return");
6277 if (OldClass != NewClass &&
6278 !CastToBaseClass(Info, E, Result&: LVal, DerivedRD: OldClass, BaseRD: NewClass))
6279 return false;
6280 OldClass = NewClass;
6281 }
6282
6283 LVal.moveInto(V&: Result);
6284 return true;
6285}
6286
6287/// Determine whether \p Base, which is known to be a direct base class of
6288/// \p Derived, is a public base class.
6289static bool isBaseClassPublic(const CXXRecordDecl *Derived,
6290 const CXXRecordDecl *Base) {
6291 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
6292 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
6293 if (BaseClass && declaresSameEntity(D1: BaseClass, D2: Base))
6294 return BaseSpec.getAccessSpecifier() == AS_public;
6295 }
6296 llvm_unreachable("Base is not a direct base of Derived");
6297}
6298
6299/// Apply the given dynamic cast operation on the provided lvalue.
6300///
6301/// This implements the hard case of dynamic_cast, requiring a "runtime check"
6302/// to find a suitable target subobject.
6303static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
6304 LValue &Ptr) {
6305 // We can't do anything with a non-symbolic pointer value.
6306 SubobjectDesignator &D = Ptr.Designator;
6307 if (D.Invalid)
6308 return false;
6309
6310 // C++ [expr.dynamic.cast]p6:
6311 // If v is a null pointer value, the result is a null pointer value.
6312 if (Ptr.isNullPointer() && !E->isGLValue())
6313 return true;
6314
6315 // For all the other cases, we need the pointer to point to an object within
6316 // its lifetime / period of construction / destruction, and we need to know
6317 // its dynamic type.
6318 std::optional<DynamicType> DynType =
6319 ComputeDynamicType(Info, E, This&: Ptr, AK: AK_DynamicCast);
6320 if (!DynType)
6321 return false;
6322
6323 // C++ [expr.dynamic.cast]p7:
6324 // If T is "pointer to cv void", then the result is a pointer to the most
6325 // derived object
6326 if (E->getType()->isVoidPointerType())
6327 return CastToDerivedClass(Info, E, Result&: Ptr, TruncatedType: DynType->Type, TruncatedElements: DynType->PathLength);
6328
6329 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
6330 assert(C && "dynamic_cast target is not void pointer nor class");
6331 CanQualType CQT = Info.Ctx.getCanonicalType(T: Info.Ctx.getRecordType(Decl: C));
6332
6333 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
6334 // C++ [expr.dynamic.cast]p9:
6335 if (!E->isGLValue()) {
6336 // The value of a failed cast to pointer type is the null pointer value
6337 // of the required result type.
6338 Ptr.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
6339 return true;
6340 }
6341
6342 // A failed cast to reference type throws [...] std::bad_cast.
6343 unsigned DiagKind;
6344 if (!Paths && (declaresSameEntity(D1: DynType->Type, D2: C) ||
6345 DynType->Type->isDerivedFrom(Base: C)))
6346 DiagKind = 0;
6347 else if (!Paths || Paths->begin() == Paths->end())
6348 DiagKind = 1;
6349 else if (Paths->isAmbiguous(BaseType: CQT))
6350 DiagKind = 2;
6351 else {
6352 assert(Paths->front().Access != AS_public && "why did the cast fail?");
6353 DiagKind = 3;
6354 }
6355 Info.FFDiag(E, DiagId: diag::note_constexpr_dynamic_cast_to_reference_failed)
6356 << DiagKind << Ptr.Designator.getType(Ctx&: Info.Ctx)
6357 << Info.Ctx.getRecordType(Decl: DynType->Type)
6358 << E->getType().getUnqualifiedType();
6359 return false;
6360 };
6361
6362 // Runtime check, phase 1:
6363 // Walk from the base subobject towards the derived object looking for the
6364 // target type.
6365 for (int PathLength = Ptr.Designator.Entries.size();
6366 PathLength >= (int)DynType->PathLength; --PathLength) {
6367 const CXXRecordDecl *Class = getBaseClassType(Designator&: Ptr.Designator, PathLength);
6368 if (declaresSameEntity(D1: Class, D2: C))
6369 return CastToDerivedClass(Info, E, Result&: Ptr, TruncatedType: Class, TruncatedElements: PathLength);
6370 // We can only walk across public inheritance edges.
6371 if (PathLength > (int)DynType->PathLength &&
6372 !isBaseClassPublic(Derived: getBaseClassType(Designator&: Ptr.Designator, PathLength: PathLength - 1),
6373 Base: Class))
6374 return RuntimeCheckFailed(nullptr);
6375 }
6376
6377 // Runtime check, phase 2:
6378 // Search the dynamic type for an unambiguous public base of type C.
6379 CXXBasePaths Paths(/*FindAmbiguities=*/true,
6380 /*RecordPaths=*/true, /*DetectVirtual=*/false);
6381 if (DynType->Type->isDerivedFrom(Base: C, Paths) && !Paths.isAmbiguous(BaseType: CQT) &&
6382 Paths.front().Access == AS_public) {
6383 // Downcast to the dynamic type...
6384 if (!CastToDerivedClass(Info, E, Result&: Ptr, TruncatedType: DynType->Type, TruncatedElements: DynType->PathLength))
6385 return false;
6386 // ... then upcast to the chosen base class subobject.
6387 for (CXXBasePathElement &Elem : Paths.front())
6388 if (!HandleLValueBase(Info, E, Obj&: Ptr, DerivedDecl: Elem.Class, Base: Elem.Base))
6389 return false;
6390 return true;
6391 }
6392
6393 // Otherwise, the runtime check fails.
6394 return RuntimeCheckFailed(&Paths);
6395}
6396
6397namespace {
6398struct StartLifetimeOfUnionMemberHandler {
6399 EvalInfo &Info;
6400 const Expr *LHSExpr;
6401 const FieldDecl *Field;
6402 bool DuringInit;
6403 bool Failed = false;
6404 static const AccessKinds AccessKind = AK_Assign;
6405
6406 typedef bool result_type;
6407 bool failed() { return Failed; }
6408 bool found(APValue &Subobj, QualType SubobjType) {
6409 // We are supposed to perform no initialization but begin the lifetime of
6410 // the object. We interpret that as meaning to do what default
6411 // initialization of the object would do if all constructors involved were
6412 // trivial:
6413 // * All base, non-variant member, and array element subobjects' lifetimes
6414 // begin
6415 // * No variant members' lifetimes begin
6416 // * All scalar subobjects whose lifetimes begin have indeterminate values
6417 assert(SubobjType->isUnionType());
6418 if (declaresSameEntity(D1: Subobj.getUnionField(), D2: Field)) {
6419 // This union member is already active. If it's also in-lifetime, there's
6420 // nothing to do.
6421 if (Subobj.getUnionValue().hasValue())
6422 return true;
6423 } else if (DuringInit) {
6424 // We're currently in the process of initializing a different union
6425 // member. If we carried on, that initialization would attempt to
6426 // store to an inactive union member, resulting in undefined behavior.
6427 Info.FFDiag(E: LHSExpr,
6428 DiagId: diag::note_constexpr_union_member_change_during_init);
6429 return false;
6430 }
6431 APValue Result;
6432 Failed = !handleDefaultInitValue(T: Field->getType(), Result);
6433 Subobj.setUnion(Field, Value: Result);
6434 return true;
6435 }
6436 bool found(APSInt &Value, QualType SubobjType) {
6437 llvm_unreachable("wrong value kind for union object");
6438 }
6439 bool found(APFloat &Value, QualType SubobjType) {
6440 llvm_unreachable("wrong value kind for union object");
6441 }
6442};
6443} // end anonymous namespace
6444
6445const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;
6446
6447/// Handle a builtin simple-assignment or a call to a trivial assignment
6448/// operator whose left-hand side might involve a union member access. If it
6449/// does, implicitly start the lifetime of any accessed union elements per
6450/// C++20 [class.union]5.
6451static bool MaybeHandleUnionActiveMemberChange(EvalInfo &Info,
6452 const Expr *LHSExpr,
6453 const LValue &LHS) {
6454 if (LHS.InvalidBase || LHS.Designator.Invalid)
6455 return false;
6456
6457 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
6458 // C++ [class.union]p5:
6459 // define the set S(E) of subexpressions of E as follows:
6460 unsigned PathLength = LHS.Designator.Entries.size();
6461 for (const Expr *E = LHSExpr; E != nullptr;) {
6462 // -- If E is of the form A.B, S(E) contains the elements of S(A)...
6463 if (auto *ME = dyn_cast<MemberExpr>(Val: E)) {
6464 auto *FD = dyn_cast<FieldDecl>(Val: ME->getMemberDecl());
6465 // Note that we can't implicitly start the lifetime of a reference,
6466 // so we don't need to proceed any further if we reach one.
6467 if (!FD || FD->getType()->isReferenceType())
6468 break;
6469
6470 // ... and also contains A.B if B names a union member ...
6471 if (FD->getParent()->isUnion()) {
6472 // ... of a non-class, non-array type, or of a class type with a
6473 // trivial default constructor that is not deleted, or an array of
6474 // such types.
6475 auto *RD =
6476 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
6477 if (!RD || RD->hasTrivialDefaultConstructor())
6478 UnionPathLengths.push_back(Elt: {PathLength - 1, FD});
6479 }
6480
6481 E = ME->getBase();
6482 --PathLength;
6483 assert(declaresSameEntity(FD,
6484 LHS.Designator.Entries[PathLength]
6485 .getAsBaseOrMember().getPointer()));
6486
6487 // -- If E is of the form A[B] and is interpreted as a built-in array
6488 // subscripting operator, S(E) is [S(the array operand, if any)].
6489 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Val: E)) {
6490 // Step over an ArrayToPointerDecay implicit cast.
6491 auto *Base = ASE->getBase()->IgnoreImplicit();
6492 if (!Base->getType()->isArrayType())
6493 break;
6494
6495 E = Base;
6496 --PathLength;
6497
6498 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(Val: E)) {
6499 // Step over a derived-to-base conversion.
6500 E = ICE->getSubExpr();
6501 if (ICE->getCastKind() == CK_NoOp)
6502 continue;
6503 if (ICE->getCastKind() != CK_DerivedToBase &&
6504 ICE->getCastKind() != CK_UncheckedDerivedToBase)
6505 break;
6506 // Walk path backwards as we walk up from the base to the derived class.
6507 for (const CXXBaseSpecifier *Elt : llvm::reverse(C: ICE->path())) {
6508 if (Elt->isVirtual()) {
6509 // A class with virtual base classes never has a trivial default
6510 // constructor, so S(E) is empty in this case.
6511 E = nullptr;
6512 break;
6513 }
6514
6515 --PathLength;
6516 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
6517 LHS.Designator.Entries[PathLength]
6518 .getAsBaseOrMember().getPointer()));
6519 }
6520
6521 // -- Otherwise, S(E) is empty.
6522 } else {
6523 break;
6524 }
6525 }
6526
6527 // Common case: no unions' lifetimes are started.
6528 if (UnionPathLengths.empty())
6529 return true;
6530
6531 // if modification of X [would access an inactive union member], an object
6532 // of the type of X is implicitly created
6533 CompleteObject Obj =
6534 findCompleteObject(Info, E: LHSExpr, AK: AK_Assign, LVal: LHS, LValType: LHSExpr->getType());
6535 if (!Obj)
6536 return false;
6537 for (std::pair<unsigned, const FieldDecl *> LengthAndField :
6538 llvm::reverse(C&: UnionPathLengths)) {
6539 // Form a designator for the union object.
6540 SubobjectDesignator D = LHS.Designator;
6541 D.truncate(Ctx&: Info.Ctx, Base: LHS.Base, NewLength: LengthAndField.first);
6542
6543 bool DuringInit = Info.isEvaluatingCtorDtor(Base: LHS.Base, Path: D.Entries) ==
6544 ConstructionPhase::AfterBases;
6545 StartLifetimeOfUnionMemberHandler StartLifetime{
6546 .Info: Info, .LHSExpr: LHSExpr, .Field: LengthAndField.second, .DuringInit: DuringInit};
6547 if (!findSubobject(Info, E: LHSExpr, Obj, Sub: D, handler&: StartLifetime))
6548 return false;
6549 }
6550
6551 return true;
6552}
6553
6554static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg,
6555 CallRef Call, EvalInfo &Info, bool NonNull = false,
6556 APValue **EvaluatedArg = nullptr) {
6557 LValue LV;
6558 // Create the parameter slot and register its destruction. For a vararg
6559 // argument, create a temporary.
6560 // FIXME: For calling conventions that destroy parameters in the callee,
6561 // should we consider performing destruction when the function returns
6562 // instead?
6563 APValue &V = PVD ? Info.CurrentCall->createParam(Args: Call, PVD, LV)
6564 : Info.CurrentCall->createTemporary(Key: Arg, T: Arg->getType(),
6565 Scope: ScopeKind::Call, LV);
6566 if (!EvaluateInPlace(Result&: V, Info, This: LV, E: Arg))
6567 return false;
6568
6569 // Passing a null pointer to an __attribute__((nonnull)) parameter results in
6570 // undefined behavior, so is non-constant.
6571 if (NonNull && V.isLValue() && V.isNullPointer()) {
6572 Info.CCEDiag(E: Arg, DiagId: diag::note_non_null_attribute_failed);
6573 return false;
6574 }
6575
6576 if (EvaluatedArg)
6577 *EvaluatedArg = &V;
6578
6579 return true;
6580}
6581
6582/// Evaluate the arguments to a function call.
6583static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call,
6584 EvalInfo &Info, const FunctionDecl *Callee,
6585 bool RightToLeft = false,
6586 LValue *ObjectArg = nullptr) {
6587 bool Success = true;
6588 llvm::SmallBitVector ForbiddenNullArgs;
6589 if (Callee->hasAttr<NonNullAttr>()) {
6590 ForbiddenNullArgs.resize(N: Args.size());
6591 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
6592 if (!Attr->args_size()) {
6593 ForbiddenNullArgs.set();
6594 break;
6595 } else
6596 for (auto Idx : Attr->args()) {
6597 unsigned ASTIdx = Idx.getASTIndex();
6598 if (ASTIdx >= Args.size())
6599 continue;
6600 ForbiddenNullArgs[ASTIdx] = true;
6601 }
6602 }
6603 }
6604 for (unsigned I = 0; I < Args.size(); I++) {
6605 unsigned Idx = RightToLeft ? Args.size() - I - 1 : I;
6606 const ParmVarDecl *PVD =
6607 Idx < Callee->getNumParams() ? Callee->getParamDecl(i: Idx) : nullptr;
6608 bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx];
6609 APValue *That = nullptr;
6610 if (!EvaluateCallArg(PVD, Arg: Args[Idx], Call, Info, NonNull, EvaluatedArg: &That)) {
6611 // If we're checking for a potential constant expression, evaluate all
6612 // initializers even if some of them fail.
6613 if (!Info.noteFailure())
6614 return false;
6615 Success = false;
6616 }
6617 if (PVD && PVD->isExplicitObjectParameter() && That && That->isLValue())
6618 ObjectArg->setFrom(Ctx&: Info.Ctx, V: *That);
6619 }
6620 return Success;
6621}
6622
6623/// Perform a trivial copy from Param, which is the parameter of a copy or move
6624/// constructor or assignment operator.
6625static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param,
6626 const Expr *E, APValue &Result,
6627 bool CopyObjectRepresentation) {
6628 // Find the reference argument.
6629 CallStackFrame *Frame = Info.CurrentCall;
6630 APValue *RefValue = Info.getParamSlot(Call: Frame->Arguments, PVD: Param);
6631 if (!RefValue) {
6632 Info.FFDiag(E);
6633 return false;
6634 }
6635
6636 // Copy out the contents of the RHS object.
6637 LValue RefLValue;
6638 RefLValue.setFrom(Ctx&: Info.Ctx, V: *RefValue);
6639 return handleLValueToRValueConversion(
6640 Info, Conv: E, Type: Param->getType().getNonReferenceType(), LVal: RefLValue, RVal&: Result,
6641 WantObjectRepresentation: CopyObjectRepresentation);
6642}
6643
6644/// Evaluate a function call.
6645static bool HandleFunctionCall(SourceLocation CallLoc,
6646 const FunctionDecl *Callee,
6647 const LValue *ObjectArg, const Expr *E,
6648 ArrayRef<const Expr *> Args, CallRef Call,
6649 const Stmt *Body, EvalInfo &Info,
6650 APValue &Result, const LValue *ResultSlot) {
6651 if (!Info.CheckCallLimit(Loc: CallLoc))
6652 return false;
6653
6654 CallStackFrame Frame(Info, E->getSourceRange(), Callee, ObjectArg, E, Call);
6655
6656 // For a trivial copy or move assignment, perform an APValue copy. This is
6657 // essential for unions, where the operations performed by the assignment
6658 // operator cannot be represented as statements.
6659 //
6660 // Skip this for non-union classes with no fields; in that case, the defaulted
6661 // copy/move does not actually read the object.
6662 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: Callee);
6663 if (MD && MD->isDefaulted() &&
6664 (MD->getParent()->isUnion() ||
6665 (MD->isTrivial() &&
6666 isReadByLvalueToRvalueConversion(RD: MD->getParent())))) {
6667 unsigned ExplicitOffset = MD->isExplicitObjectMemberFunction() ? 1 : 0;
6668 assert(ObjectArg &&
6669 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
6670 APValue RHSValue;
6671 if (!handleTrivialCopy(Info, Param: MD->getParamDecl(i: 0), E: Args[0], Result&: RHSValue,
6672 CopyObjectRepresentation: MD->getParent()->isUnion()))
6673 return false;
6674
6675 LValue Obj;
6676 if (!handleAssignment(Info, E: Args[ExplicitOffset], LVal: *ObjectArg,
6677 LValType: MD->getFunctionObjectParameterReferenceType(),
6678 Val&: RHSValue))
6679 return false;
6680 ObjectArg->moveInto(V&: Result);
6681 return true;
6682 } else if (MD && isLambdaCallOperator(MD)) {
6683 // We're in a lambda; determine the lambda capture field maps unless we're
6684 // just constexpr checking a lambda's call operator. constexpr checking is
6685 // done before the captures have been added to the closure object (unless
6686 // we're inferring constexpr-ness), so we don't have access to them in this
6687 // case. But since we don't need the captures to constexpr check, we can
6688 // just ignore them.
6689 if (!Info.checkingPotentialConstantExpression())
6690 MD->getParent()->getCaptureFields(Captures&: Frame.LambdaCaptureFields,
6691 ThisCapture&: Frame.LambdaThisCaptureField);
6692 }
6693
6694 StmtResult Ret = {.Value: Result, .Slot: ResultSlot};
6695 EvalStmtResult ESR = EvaluateStmt(Result&: Ret, Info, S: Body);
6696 if (ESR == ESR_Succeeded) {
6697 if (Callee->getReturnType()->isVoidType())
6698 return true;
6699 Info.FFDiag(Loc: Callee->getEndLoc(), DiagId: diag::note_constexpr_no_return);
6700 }
6701 return ESR == ESR_Returned;
6702}
6703
6704/// Evaluate a constructor call.
6705static bool HandleConstructorCall(const Expr *E, const LValue &This,
6706 CallRef Call,
6707 const CXXConstructorDecl *Definition,
6708 EvalInfo &Info, APValue &Result) {
6709 SourceLocation CallLoc = E->getExprLoc();
6710 if (!Info.CheckCallLimit(Loc: CallLoc))
6711 return false;
6712
6713 const CXXRecordDecl *RD = Definition->getParent();
6714 if (RD->getNumVBases()) {
6715 Info.FFDiag(Loc: CallLoc, DiagId: diag::note_constexpr_virtual_base) << RD;
6716 return false;
6717 }
6718
6719 EvalInfo::EvaluatingConstructorRAII EvalObj(
6720 Info,
6721 ObjectUnderConstruction{.Base: This.getLValueBase(), .Path: This.Designator.Entries},
6722 RD->getNumBases());
6723 CallStackFrame Frame(Info, E->getSourceRange(), Definition, &This, E, Call);
6724
6725 // FIXME: Creating an APValue just to hold a nonexistent return value is
6726 // wasteful.
6727 APValue RetVal;
6728 StmtResult Ret = {.Value: RetVal, .Slot: nullptr};
6729
6730 // If it's a delegating constructor, delegate.
6731 if (Definition->isDelegatingConstructor()) {
6732 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
6733 if ((*I)->getInit()->isValueDependent()) {
6734 if (!EvaluateDependentExpr(E: (*I)->getInit(), Info))
6735 return false;
6736 } else {
6737 FullExpressionRAII InitScope(Info);
6738 if (!EvaluateInPlace(Result, Info, This, E: (*I)->getInit()) ||
6739 !InitScope.destroy())
6740 return false;
6741 }
6742 return EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) != ESR_Failed;
6743 }
6744
6745 // For a trivial copy or move constructor, perform an APValue copy. This is
6746 // essential for unions (or classes with anonymous union members), where the
6747 // operations performed by the constructor cannot be represented by
6748 // ctor-initializers.
6749 //
6750 // Skip this for empty non-union classes; we should not perform an
6751 // lvalue-to-rvalue conversion on them because their copy constructor does not
6752 // actually read them.
6753 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
6754 (Definition->getParent()->isUnion() ||
6755 (Definition->isTrivial() &&
6756 isReadByLvalueToRvalueConversion(RD: Definition->getParent())))) {
6757 return handleTrivialCopy(Info, Param: Definition->getParamDecl(i: 0), E, Result,
6758 CopyObjectRepresentation: Definition->getParent()->isUnion());
6759 }
6760
6761 // Reserve space for the struct members.
6762 if (!Result.hasValue()) {
6763 if (!RD->isUnion())
6764 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
6765 std::distance(first: RD->field_begin(), last: RD->field_end()));
6766 else
6767 // A union starts with no active member.
6768 Result = APValue((const FieldDecl*)nullptr);
6769 }
6770
6771 if (RD->isInvalidDecl()) return false;
6772 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
6773
6774 // A scope for temporaries lifetime-extended by reference members.
6775 BlockScopeRAII LifetimeExtendedScope(Info);
6776
6777 bool Success = true;
6778 unsigned BasesSeen = 0;
6779#ifndef NDEBUG
6780 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
6781#endif
6782 CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
6783 auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
6784 // We might be initializing the same field again if this is an indirect
6785 // field initialization.
6786 if (FieldIt == RD->field_end() ||
6787 FieldIt->getFieldIndex() > FD->getFieldIndex()) {
6788 assert(Indirect && "fields out of order?");
6789 return;
6790 }
6791
6792 // Default-initialize any fields with no explicit initializer.
6793 for (; !declaresSameEntity(D1: *FieldIt, D2: FD); ++FieldIt) {
6794 assert(FieldIt != RD->field_end() && "missing field?");
6795 if (!FieldIt->isUnnamedBitField())
6796 Success &= handleDefaultInitValue(
6797 T: FieldIt->getType(),
6798 Result&: Result.getStructField(i: FieldIt->getFieldIndex()));
6799 }
6800 ++FieldIt;
6801 };
6802 for (const auto *I : Definition->inits()) {
6803 LValue Subobject = This;
6804 LValue SubobjectParent = This;
6805 APValue *Value = &Result;
6806
6807 // Determine the subobject to initialize.
6808 FieldDecl *FD = nullptr;
6809 if (I->isBaseInitializer()) {
6810 QualType BaseType(I->getBaseClass(), 0);
6811#ifndef NDEBUG
6812 // Non-virtual base classes are initialized in the order in the class
6813 // definition. We have already checked for virtual base classes.
6814 assert(!BaseIt->isVirtual() && "virtual base for literal type");
6815 assert(Info.Ctx.hasSameUnqualifiedType(BaseIt->getType(), BaseType) &&
6816 "base class initializers not in expected order");
6817 ++BaseIt;
6818#endif
6819 if (!HandleLValueDirectBase(Info, E: I->getInit(), Obj&: Subobject, Derived: RD,
6820 Base: BaseType->getAsCXXRecordDecl(), RL: &Layout))
6821 return false;
6822 Value = &Result.getStructBase(i: BasesSeen++);
6823 } else if ((FD = I->getMember())) {
6824 if (!HandleLValueMember(Info, E: I->getInit(), LVal&: Subobject, FD, RL: &Layout))
6825 return false;
6826 if (RD->isUnion()) {
6827 Result = APValue(FD);
6828 Value = &Result.getUnionValue();
6829 } else {
6830 SkipToField(FD, false);
6831 Value = &Result.getStructField(i: FD->getFieldIndex());
6832 }
6833 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
6834 // Walk the indirect field decl's chain to find the object to initialize,
6835 // and make sure we've initialized every step along it.
6836 auto IndirectFieldChain = IFD->chain();
6837 for (auto *C : IndirectFieldChain) {
6838 FD = cast<FieldDecl>(Val: C);
6839 CXXRecordDecl *CD = cast<CXXRecordDecl>(Val: FD->getParent());
6840 // Switch the union field if it differs. This happens if we had
6841 // preceding zero-initialization, and we're now initializing a union
6842 // subobject other than the first.
6843 // FIXME: In this case, the values of the other subobjects are
6844 // specified, since zero-initialization sets all padding bits to zero.
6845 if (!Value->hasValue() ||
6846 (Value->isUnion() &&
6847 !declaresSameEntity(D1: Value->getUnionField(), D2: FD))) {
6848 if (CD->isUnion())
6849 *Value = APValue(FD);
6850 else
6851 // FIXME: This immediately starts the lifetime of all members of
6852 // an anonymous struct. It would be preferable to strictly start
6853 // member lifetime in initialization order.
6854 Success &=
6855 handleDefaultInitValue(T: Info.Ctx.getRecordType(Decl: CD), Result&: *Value);
6856 }
6857 // Store Subobject as its parent before updating it for the last element
6858 // in the chain.
6859 if (C == IndirectFieldChain.back())
6860 SubobjectParent = Subobject;
6861 if (!HandleLValueMember(Info, E: I->getInit(), LVal&: Subobject, FD))
6862 return false;
6863 if (CD->isUnion())
6864 Value = &Value->getUnionValue();
6865 else {
6866 if (C == IndirectFieldChain.front() && !RD->isUnion())
6867 SkipToField(FD, true);
6868 Value = &Value->getStructField(i: FD->getFieldIndex());
6869 }
6870 }
6871 } else {
6872 llvm_unreachable("unknown base initializer kind");
6873 }
6874
6875 // Need to override This for implicit field initializers as in this case
6876 // This refers to innermost anonymous struct/union containing initializer,
6877 // not to currently constructed class.
6878 const Expr *Init = I->getInit();
6879 if (Init->isValueDependent()) {
6880 if (!EvaluateDependentExpr(E: Init, Info))
6881 return false;
6882 } else {
6883 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
6884 isa<CXXDefaultInitExpr>(Val: Init));
6885 FullExpressionRAII InitScope(Info);
6886 if (!EvaluateInPlace(Result&: *Value, Info, This: Subobject, E: Init) ||
6887 (FD && FD->isBitField() &&
6888 !truncateBitfieldValue(Info, E: Init, Value&: *Value, FD))) {
6889 // If we're checking for a potential constant expression, evaluate all
6890 // initializers even if some of them fail.
6891 if (!Info.noteFailure())
6892 return false;
6893 Success = false;
6894 }
6895 }
6896
6897 // This is the point at which the dynamic type of the object becomes this
6898 // class type.
6899 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
6900 EvalObj.finishedConstructingBases();
6901 }
6902
6903 // Default-initialize any remaining fields.
6904 if (!RD->isUnion()) {
6905 for (; FieldIt != RD->field_end(); ++FieldIt) {
6906 if (!FieldIt->isUnnamedBitField())
6907 Success &= handleDefaultInitValue(
6908 T: FieldIt->getType(),
6909 Result&: Result.getStructField(i: FieldIt->getFieldIndex()));
6910 }
6911 }
6912
6913 EvalObj.finishedConstructingFields();
6914
6915 return Success &&
6916 EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) != ESR_Failed &&
6917 LifetimeExtendedScope.destroy();
6918}
6919
6920static bool HandleConstructorCall(const Expr *E, const LValue &This,
6921 ArrayRef<const Expr*> Args,
6922 const CXXConstructorDecl *Definition,
6923 EvalInfo &Info, APValue &Result) {
6924 CallScopeRAII CallScope(Info);
6925 CallRef Call = Info.CurrentCall->createCall(Callee: Definition);
6926 if (!EvaluateArgs(Args, Call, Info, Callee: Definition))
6927 return false;
6928
6929 return HandleConstructorCall(E, This, Call, Definition, Info, Result) &&
6930 CallScope.destroy();
6931}
6932
6933static bool HandleDestructionImpl(EvalInfo &Info, SourceRange CallRange,
6934 const LValue &This, APValue &Value,
6935 QualType T) {
6936 // Objects can only be destroyed while they're within their lifetimes.
6937 // FIXME: We have no representation for whether an object of type nullptr_t
6938 // is in its lifetime; it usually doesn't matter. Perhaps we should model it
6939 // as indeterminate instead?
6940 if (Value.isAbsent() && !T->isNullPtrType()) {
6941 APValue Printable;
6942 This.moveInto(V&: Printable);
6943 Info.FFDiag(Loc: CallRange.getBegin(),
6944 DiagId: diag::note_constexpr_destroy_out_of_lifetime)
6945 << Printable.getAsString(Ctx: Info.Ctx, Ty: Info.Ctx.getLValueReferenceType(T));
6946 return false;
6947 }
6948
6949 // Invent an expression for location purposes.
6950 // FIXME: We shouldn't need to do this.
6951 OpaqueValueExpr LocE(CallRange.getBegin(), Info.Ctx.IntTy, VK_PRValue);
6952
6953 // For arrays, destroy elements right-to-left.
6954 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
6955 uint64_t Size = CAT->getZExtSize();
6956 QualType ElemT = CAT->getElementType();
6957
6958 if (!CheckArraySize(Info, CAT, CallLoc: CallRange.getBegin()))
6959 return false;
6960
6961 LValue ElemLV = This;
6962 ElemLV.addArray(Info, E: &LocE, CAT);
6963 if (!HandleLValueArrayAdjustment(Info, E: &LocE, LVal&: ElemLV, EltTy: ElemT, Adjustment: Size))
6964 return false;
6965
6966 // Ensure that we have actual array elements available to destroy; the
6967 // destructors might mutate the value, so we can't run them on the array
6968 // filler.
6969 if (Size && Size > Value.getArrayInitializedElts())
6970 expandArray(Array&: Value, Index: Value.getArraySize() - 1);
6971
6972 // The size of the array might have been reduced by
6973 // a placement new.
6974 for (Size = Value.getArraySize(); Size != 0; --Size) {
6975 APValue &Elem = Value.getArrayInitializedElt(I: Size - 1);
6976 if (!HandleLValueArrayAdjustment(Info, E: &LocE, LVal&: ElemLV, EltTy: ElemT, Adjustment: -1) ||
6977 !HandleDestructionImpl(Info, CallRange, This: ElemLV, Value&: Elem, T: ElemT))
6978 return false;
6979 }
6980
6981 // End the lifetime of this array now.
6982 Value = APValue();
6983 return true;
6984 }
6985
6986 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
6987 if (!RD) {
6988 if (T.isDestructedType()) {
6989 Info.FFDiag(Loc: CallRange.getBegin(),
6990 DiagId: diag::note_constexpr_unsupported_destruction)
6991 << T;
6992 return false;
6993 }
6994
6995 Value = APValue();
6996 return true;
6997 }
6998
6999 if (RD->getNumVBases()) {
7000 Info.FFDiag(Loc: CallRange.getBegin(), DiagId: diag::note_constexpr_virtual_base) << RD;
7001 return false;
7002 }
7003
7004 const CXXDestructorDecl *DD = RD->getDestructor();
7005 if (!DD && !RD->hasTrivialDestructor()) {
7006 Info.FFDiag(Loc: CallRange.getBegin());
7007 return false;
7008 }
7009
7010 if (!DD || DD->isTrivial() ||
7011 (RD->isAnonymousStructOrUnion() && RD->isUnion())) {
7012 // A trivial destructor just ends the lifetime of the object. Check for
7013 // this case before checking for a body, because we might not bother
7014 // building a body for a trivial destructor. Note that it doesn't matter
7015 // whether the destructor is constexpr in this case; all trivial
7016 // destructors are constexpr.
7017 //
7018 // If an anonymous union would be destroyed, some enclosing destructor must
7019 // have been explicitly defined, and the anonymous union destruction should
7020 // have no effect.
7021 Value = APValue();
7022 return true;
7023 }
7024
7025 if (!Info.CheckCallLimit(Loc: CallRange.getBegin()))
7026 return false;
7027
7028 const FunctionDecl *Definition = nullptr;
7029 const Stmt *Body = DD->getBody(Definition);
7030
7031 if (!CheckConstexprFunction(Info, CallLoc: CallRange.getBegin(), Declaration: DD, Definition, Body))
7032 return false;
7033
7034 CallStackFrame Frame(Info, CallRange, Definition, &This, /*CallExpr=*/nullptr,
7035 CallRef());
7036
7037 // We're now in the period of destruction of this object.
7038 unsigned BasesLeft = RD->getNumBases();
7039 EvalInfo::EvaluatingDestructorRAII EvalObj(
7040 Info,
7041 ObjectUnderConstruction{.Base: This.getLValueBase(), .Path: This.Designator.Entries});
7042 if (!EvalObj.DidInsert) {
7043 // C++2a [class.dtor]p19:
7044 // the behavior is undefined if the destructor is invoked for an object
7045 // whose lifetime has ended
7046 // (Note that formally the lifetime ends when the period of destruction
7047 // begins, even though certain uses of the object remain valid until the
7048 // period of destruction ends.)
7049 Info.FFDiag(Loc: CallRange.getBegin(), DiagId: diag::note_constexpr_double_destroy);
7050 return false;
7051 }
7052
7053 // FIXME: Creating an APValue just to hold a nonexistent return value is
7054 // wasteful.
7055 APValue RetVal;
7056 StmtResult Ret = {.Value: RetVal, .Slot: nullptr};
7057 if (EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) == ESR_Failed)
7058 return false;
7059
7060 // A union destructor does not implicitly destroy its members.
7061 if (RD->isUnion())
7062 return true;
7063
7064 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
7065
7066 // We don't have a good way to iterate fields in reverse, so collect all the
7067 // fields first and then walk them backwards.
7068 SmallVector<FieldDecl*, 16> Fields(RD->fields());
7069 for (const FieldDecl *FD : llvm::reverse(C&: Fields)) {
7070 if (FD->isUnnamedBitField())
7071 continue;
7072
7073 LValue Subobject = This;
7074 if (!HandleLValueMember(Info, E: &LocE, LVal&: Subobject, FD, RL: &Layout))
7075 return false;
7076
7077 APValue *SubobjectValue = &Value.getStructField(i: FD->getFieldIndex());
7078 if (!HandleDestructionImpl(Info, CallRange, This: Subobject, Value&: *SubobjectValue,
7079 T: FD->getType()))
7080 return false;
7081 }
7082
7083 if (BasesLeft != 0)
7084 EvalObj.startedDestroyingBases();
7085
7086 // Destroy base classes in reverse order.
7087 for (const CXXBaseSpecifier &Base : llvm::reverse(C: RD->bases())) {
7088 --BasesLeft;
7089
7090 QualType BaseType = Base.getType();
7091 LValue Subobject = This;
7092 if (!HandleLValueDirectBase(Info, E: &LocE, Obj&: Subobject, Derived: RD,
7093 Base: BaseType->getAsCXXRecordDecl(), RL: &Layout))
7094 return false;
7095
7096 APValue *SubobjectValue = &Value.getStructBase(i: BasesLeft);
7097 if (!HandleDestructionImpl(Info, CallRange, This: Subobject, Value&: *SubobjectValue,
7098 T: BaseType))
7099 return false;
7100 }
7101 assert(BasesLeft == 0 && "NumBases was wrong?");
7102
7103 // The period of destruction ends now. The object is gone.
7104 Value = APValue();
7105 return true;
7106}
7107
7108namespace {
7109struct DestroyObjectHandler {
7110 EvalInfo &Info;
7111 const Expr *E;
7112 const LValue &This;
7113 const AccessKinds AccessKind;
7114
7115 typedef bool result_type;
7116 bool failed() { return false; }
7117 bool found(APValue &Subobj, QualType SubobjType) {
7118 return HandleDestructionImpl(Info, CallRange: E->getSourceRange(), This, Value&: Subobj,
7119 T: SubobjType);
7120 }
7121 bool found(APSInt &Value, QualType SubobjType) {
7122 Info.FFDiag(E, DiagId: diag::note_constexpr_destroy_complex_elem);
7123 return false;
7124 }
7125 bool found(APFloat &Value, QualType SubobjType) {
7126 Info.FFDiag(E, DiagId: diag::note_constexpr_destroy_complex_elem);
7127 return false;
7128 }
7129};
7130}
7131
7132/// Perform a destructor or pseudo-destructor call on the given object, which
7133/// might in general not be a complete object.
7134static bool HandleDestruction(EvalInfo &Info, const Expr *E,
7135 const LValue &This, QualType ThisType) {
7136 CompleteObject Obj = findCompleteObject(Info, E, AK: AK_Destroy, LVal: This, LValType: ThisType);
7137 DestroyObjectHandler Handler = {.Info: Info, .E: E, .This: This, .AccessKind: AK_Destroy};
7138 return Obj && findSubobject(Info, E, Obj, Sub: This.Designator, handler&: Handler);
7139}
7140
7141/// Destroy and end the lifetime of the given complete object.
7142static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
7143 APValue::LValueBase LVBase, APValue &Value,
7144 QualType T) {
7145 // If we've had an unmodeled side-effect, we can't rely on mutable state
7146 // (such as the object we're about to destroy) being correct.
7147 if (Info.EvalStatus.HasSideEffects)
7148 return false;
7149
7150 LValue LV;
7151 LV.set(B: {LVBase});
7152 return HandleDestructionImpl(Info, CallRange: Loc, This: LV, Value, T);
7153}
7154
7155/// Perform a call to 'operator new' or to `__builtin_operator_new'.
7156static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
7157 LValue &Result) {
7158 if (Info.checkingPotentialConstantExpression() ||
7159 Info.SpeculativeEvaluationDepth)
7160 return false;
7161
7162 // This is permitted only within a call to std::allocator<T>::allocate.
7163 auto Caller = Info.getStdAllocatorCaller(FnName: "allocate");
7164 if (!Caller) {
7165 Info.FFDiag(Loc: E->getExprLoc(), DiagId: Info.getLangOpts().CPlusPlus20
7166 ? diag::note_constexpr_new_untyped
7167 : diag::note_constexpr_new);
7168 return false;
7169 }
7170
7171 QualType ElemType = Caller.ElemType;
7172 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
7173 Info.FFDiag(Loc: E->getExprLoc(),
7174 DiagId: diag::note_constexpr_new_not_complete_object_type)
7175 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
7176 return false;
7177 }
7178
7179 APSInt ByteSize;
7180 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: ByteSize, Info))
7181 return false;
7182 bool IsNothrow = false;
7183 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
7184 EvaluateIgnoredValue(Info, E: E->getArg(Arg: I));
7185 IsNothrow |= E->getType()->isNothrowT();
7186 }
7187
7188 CharUnits ElemSize;
7189 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: ElemType, Size&: ElemSize))
7190 return false;
7191 APInt Size, Remainder;
7192 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
7193 APInt::udivrem(LHS: ByteSize, RHS: ElemSizeAP, Quotient&: Size, Remainder);
7194 if (Remainder != 0) {
7195 // This likely indicates a bug in the implementation of 'std::allocator'.
7196 Info.FFDiag(Loc: E->getExprLoc(), DiagId: diag::note_constexpr_operator_new_bad_size)
7197 << ByteSize << APSInt(ElemSizeAP, true) << ElemType;
7198 return false;
7199 }
7200
7201 if (!Info.CheckArraySize(Loc: E->getBeginLoc(), BitWidth: ByteSize.getActiveBits(),
7202 ElemCount: Size.getZExtValue(), /*Diag=*/!IsNothrow)) {
7203 if (IsNothrow) {
7204 Result.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
7205 return true;
7206 }
7207 return false;
7208 }
7209
7210 QualType AllocType = Info.Ctx.getConstantArrayType(
7211 EltTy: ElemType, ArySize: Size, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
7212 APValue *Val = Info.createHeapAlloc(E: Caller.Call, T: AllocType, LV&: Result);
7213 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
7214 Result.addArray(Info, E, CAT: cast<ConstantArrayType>(Val&: AllocType));
7215 return true;
7216}
7217
7218static bool hasVirtualDestructor(QualType T) {
7219 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
7220 if (CXXDestructorDecl *DD = RD->getDestructor())
7221 return DD->isVirtual();
7222 return false;
7223}
7224
7225static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
7226 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
7227 if (CXXDestructorDecl *DD = RD->getDestructor())
7228 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
7229 return nullptr;
7230}
7231
7232/// Check that the given object is a suitable pointer to a heap allocation that
7233/// still exists and is of the right kind for the purpose of a deletion.
7234///
7235/// On success, returns the heap allocation to deallocate. On failure, produces
7236/// a diagnostic and returns std::nullopt.
7237static std::optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
7238 const LValue &Pointer,
7239 DynAlloc::Kind DeallocKind) {
7240 auto PointerAsString = [&] {
7241 return Pointer.toString(Ctx&: Info.Ctx, T: Info.Ctx.VoidPtrTy);
7242 };
7243
7244 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
7245 if (!DA) {
7246 Info.FFDiag(E, DiagId: diag::note_constexpr_delete_not_heap_alloc)
7247 << PointerAsString();
7248 if (Pointer.Base)
7249 NoteLValueLocation(Info, Base: Pointer.Base);
7250 return std::nullopt;
7251 }
7252
7253 std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
7254 if (!Alloc) {
7255 Info.FFDiag(E, DiagId: diag::note_constexpr_double_delete);
7256 return std::nullopt;
7257 }
7258
7259 if (DeallocKind != (*Alloc)->getKind()) {
7260 QualType AllocType = Pointer.Base.getDynamicAllocType();
7261 Info.FFDiag(E, DiagId: diag::note_constexpr_new_delete_mismatch)
7262 << DeallocKind << (*Alloc)->getKind() << AllocType;
7263 NoteLValueLocation(Info, Base: Pointer.Base);
7264 return std::nullopt;
7265 }
7266
7267 bool Subobject = false;
7268 if (DeallocKind == DynAlloc::New) {
7269 Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
7270 Pointer.Designator.isOnePastTheEnd();
7271 } else {
7272 Subobject = Pointer.Designator.Entries.size() != 1 ||
7273 Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
7274 }
7275 if (Subobject) {
7276 Info.FFDiag(E, DiagId: diag::note_constexpr_delete_subobject)
7277 << PointerAsString() << Pointer.Designator.isOnePastTheEnd();
7278 return std::nullopt;
7279 }
7280
7281 return Alloc;
7282}
7283
7284// Perform a call to 'operator delete' or '__builtin_operator_delete'.
7285static bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
7286 if (Info.checkingPotentialConstantExpression() ||
7287 Info.SpeculativeEvaluationDepth)
7288 return false;
7289
7290 // This is permitted only within a call to std::allocator<T>::deallocate.
7291 if (!Info.getStdAllocatorCaller(FnName: "deallocate")) {
7292 Info.FFDiag(Loc: E->getExprLoc());
7293 return true;
7294 }
7295
7296 LValue Pointer;
7297 if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: Pointer, Info))
7298 return false;
7299 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
7300 EvaluateIgnoredValue(Info, E: E->getArg(Arg: I));
7301
7302 if (Pointer.Designator.Invalid)
7303 return false;
7304
7305 // Deleting a null pointer would have no effect, but it's not permitted by
7306 // std::allocator<T>::deallocate's contract.
7307 if (Pointer.isNullPointer()) {
7308 Info.CCEDiag(Loc: E->getExprLoc(), DiagId: diag::note_constexpr_deallocate_null);
7309 return true;
7310 }
7311
7312 if (!CheckDeleteKind(Info, E, Pointer, DeallocKind: DynAlloc::StdAllocator))
7313 return false;
7314
7315 Info.HeapAllocs.erase(x: Pointer.Base.get<DynamicAllocLValue>());
7316 return true;
7317}
7318
7319//===----------------------------------------------------------------------===//
7320// Generic Evaluation
7321//===----------------------------------------------------------------------===//
7322namespace {
7323
7324class BitCastBuffer {
7325 // FIXME: We're going to need bit-level granularity when we support
7326 // bit-fields.
7327 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
7328 // we don't support a host or target where that is the case. Still, we should
7329 // use a more generic type in case we ever do.
7330 SmallVector<std::optional<unsigned char>, 32> Bytes;
7331
7332 static_assert(std::numeric_limits<unsigned char>::digits >= 8,
7333 "Need at least 8 bit unsigned char");
7334
7335 bool TargetIsLittleEndian;
7336
7337public:
7338 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
7339 : Bytes(Width.getQuantity()),
7340 TargetIsLittleEndian(TargetIsLittleEndian) {}
7341
7342 [[nodiscard]] bool readObject(CharUnits Offset, CharUnits Width,
7343 SmallVectorImpl<unsigned char> &Output) const {
7344 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
7345 // If a byte of an integer is uninitialized, then the whole integer is
7346 // uninitialized.
7347 if (!Bytes[I.getQuantity()])
7348 return false;
7349 Output.push_back(Elt: *Bytes[I.getQuantity()]);
7350 }
7351 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
7352 std::reverse(first: Output.begin(), last: Output.end());
7353 return true;
7354 }
7355
7356 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
7357 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
7358 std::reverse(first: Input.begin(), last: Input.end());
7359
7360 size_t Index = 0;
7361 for (unsigned char Byte : Input) {
7362 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?");
7363 Bytes[Offset.getQuantity() + Index] = Byte;
7364 ++Index;
7365 }
7366 }
7367
7368 size_t size() { return Bytes.size(); }
7369};
7370
7371/// Traverse an APValue to produce an BitCastBuffer, emulating how the current
7372/// target would represent the value at runtime.
7373class APValueToBufferConverter {
7374 EvalInfo &Info;
7375 BitCastBuffer Buffer;
7376 const CastExpr *BCE;
7377
7378 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
7379 const CastExpr *BCE)
7380 : Info(Info),
7381 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
7382 BCE(BCE) {}
7383
7384 bool visit(const APValue &Val, QualType Ty) {
7385 return visit(Val, Ty, Offset: CharUnits::fromQuantity(Quantity: 0));
7386 }
7387
7388 // Write out Val with type Ty into Buffer starting at Offset.
7389 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
7390 assert((size_t)Offset.getQuantity() <= Buffer.size());
7391
7392 // As a special case, nullptr_t has an indeterminate value.
7393 if (Ty->isNullPtrType())
7394 return true;
7395
7396 // Dig through Src to find the byte at SrcOffset.
7397 switch (Val.getKind()) {
7398 case APValue::Indeterminate:
7399 case APValue::None:
7400 return true;
7401
7402 case APValue::Int:
7403 return visitInt(Val: Val.getInt(), Ty, Offset);
7404 case APValue::Float:
7405 return visitFloat(Val: Val.getFloat(), Ty, Offset);
7406 case APValue::Array:
7407 return visitArray(Val, Ty, Offset);
7408 case APValue::Struct:
7409 return visitRecord(Val, Ty, Offset);
7410 case APValue::Vector:
7411 return visitVector(Val, Ty, Offset);
7412
7413 case APValue::ComplexInt:
7414 case APValue::ComplexFloat:
7415 return visitComplex(Val, Ty, Offset);
7416 case APValue::FixedPoint:
7417 // FIXME: We should support these.
7418
7419 case APValue::Union:
7420 case APValue::MemberPointer:
7421 case APValue::AddrLabelDiff: {
7422 Info.FFDiag(Loc: BCE->getBeginLoc(),
7423 DiagId: diag::note_constexpr_bit_cast_unsupported_type)
7424 << Ty;
7425 return false;
7426 }
7427
7428 case APValue::LValue:
7429 llvm_unreachable("LValue subobject in bit_cast?");
7430 }
7431 llvm_unreachable("Unhandled APValue::ValueKind");
7432 }
7433
7434 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
7435 const RecordDecl *RD = Ty->getAsRecordDecl();
7436 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
7437
7438 // Visit the base classes.
7439 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
7440 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7441 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7442 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7443 const APValue &Base = Val.getStructBase(i: I);
7444
7445 // Can happen in error cases.
7446 if (!Base.isStruct())
7447 return false;
7448
7449 if (!visitRecord(Val: Base, Ty: BS.getType(),
7450 Offset: Layout.getBaseClassOffset(Base: BaseDecl) + Offset))
7451 return false;
7452 }
7453 }
7454
7455 // Visit the fields.
7456 unsigned FieldIdx = 0;
7457 for (FieldDecl *FD : RD->fields()) {
7458 if (FD->isBitField()) {
7459 Info.FFDiag(Loc: BCE->getBeginLoc(),
7460 DiagId: diag::note_constexpr_bit_cast_unsupported_bitfield);
7461 return false;
7462 }
7463
7464 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldNo: FieldIdx);
7465
7466 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&
7467 "only bit-fields can have sub-char alignment");
7468 CharUnits FieldOffset =
7469 Info.Ctx.toCharUnitsFromBits(BitSize: FieldOffsetBits) + Offset;
7470 QualType FieldTy = FD->getType();
7471 if (!visit(Val: Val.getStructField(i: FieldIdx), Ty: FieldTy, Offset: FieldOffset))
7472 return false;
7473 ++FieldIdx;
7474 }
7475
7476 return true;
7477 }
7478
7479 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
7480 const auto *CAT =
7481 dyn_cast_or_null<ConstantArrayType>(Val: Ty->getAsArrayTypeUnsafe());
7482 if (!CAT)
7483 return false;
7484
7485 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(T: CAT->getElementType());
7486 unsigned NumInitializedElts = Val.getArrayInitializedElts();
7487 unsigned ArraySize = Val.getArraySize();
7488 // First, initialize the initialized elements.
7489 for (unsigned I = 0; I != NumInitializedElts; ++I) {
7490 const APValue &SubObj = Val.getArrayInitializedElt(I);
7491 if (!visit(Val: SubObj, Ty: CAT->getElementType(), Offset: Offset + I * ElemWidth))
7492 return false;
7493 }
7494
7495 // Next, initialize the rest of the array using the filler.
7496 if (Val.hasArrayFiller()) {
7497 const APValue &Filler = Val.getArrayFiller();
7498 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
7499 if (!visit(Val: Filler, Ty: CAT->getElementType(), Offset: Offset + I * ElemWidth))
7500 return false;
7501 }
7502 }
7503
7504 return true;
7505 }
7506
7507 bool visitComplex(const APValue &Val, QualType Ty, CharUnits Offset) {
7508 const ComplexType *ComplexTy = Ty->castAs<ComplexType>();
7509 QualType EltTy = ComplexTy->getElementType();
7510 CharUnits EltSizeChars = Info.Ctx.getTypeSizeInChars(T: EltTy);
7511 bool IsInt = Val.isComplexInt();
7512
7513 if (IsInt) {
7514 if (!visitInt(Val: Val.getComplexIntReal(), Ty: EltTy,
7515 Offset: Offset + (0 * EltSizeChars)))
7516 return false;
7517 if (!visitInt(Val: Val.getComplexIntImag(), Ty: EltTy,
7518 Offset: Offset + (1 * EltSizeChars)))
7519 return false;
7520 } else {
7521 if (!visitFloat(Val: Val.getComplexFloatReal(), Ty: EltTy,
7522 Offset: Offset + (0 * EltSizeChars)))
7523 return false;
7524 if (!visitFloat(Val: Val.getComplexFloatImag(), Ty: EltTy,
7525 Offset: Offset + (1 * EltSizeChars)))
7526 return false;
7527 }
7528
7529 return true;
7530 }
7531
7532 bool visitVector(const APValue &Val, QualType Ty, CharUnits Offset) {
7533 const VectorType *VTy = Ty->castAs<VectorType>();
7534 QualType EltTy = VTy->getElementType();
7535 unsigned NElts = VTy->getNumElements();
7536
7537 if (VTy->isPackedVectorBoolType(ctx: Info.Ctx)) {
7538 // Special handling for OpenCL bool vectors:
7539 // Since these vectors are stored as packed bits, but we can't write
7540 // individual bits to the BitCastBuffer, we'll buffer all of the elements
7541 // together into an appropriately sized APInt and write them all out at
7542 // once. Because we don't accept vectors where NElts * EltSize isn't a
7543 // multiple of the char size, there will be no padding space, so we don't
7544 // have to worry about writing data which should have been left
7545 // uninitialized.
7546 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
7547
7548 llvm::APInt Res = llvm::APInt::getZero(numBits: NElts);
7549 for (unsigned I = 0; I < NElts; ++I) {
7550 const llvm::APSInt &EltAsInt = Val.getVectorElt(I).getInt();
7551 assert(EltAsInt.isUnsigned() && EltAsInt.getBitWidth() == 1 &&
7552 "bool vector element must be 1-bit unsigned integer!");
7553
7554 Res.insertBits(SubBits: EltAsInt, bitPosition: BigEndian ? (NElts - I - 1) : I);
7555 }
7556
7557 SmallVector<uint8_t, 8> Bytes(NElts / 8);
7558 llvm::StoreIntToMemory(IntVal: Res, Dst: &*Bytes.begin(), StoreBytes: NElts / 8);
7559 Buffer.writeObject(Offset, Input&: Bytes);
7560 } else {
7561 // Iterate over each of the elements and write them out to the buffer at
7562 // the appropriate offset.
7563 CharUnits EltSizeChars = Info.Ctx.getTypeSizeInChars(T: EltTy);
7564 for (unsigned I = 0; I < NElts; ++I) {
7565 if (!visit(Val: Val.getVectorElt(I), Ty: EltTy, Offset: Offset + I * EltSizeChars))
7566 return false;
7567 }
7568 }
7569
7570 return true;
7571 }
7572
7573 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
7574 APSInt AdjustedVal = Val;
7575 unsigned Width = AdjustedVal.getBitWidth();
7576 if (Ty->isBooleanType()) {
7577 Width = Info.Ctx.getTypeSize(T: Ty);
7578 AdjustedVal = AdjustedVal.extend(width: Width);
7579 }
7580
7581 SmallVector<uint8_t, 8> Bytes(Width / 8);
7582 llvm::StoreIntToMemory(IntVal: AdjustedVal, Dst: &*Bytes.begin(), StoreBytes: Width / 8);
7583 Buffer.writeObject(Offset, Input&: Bytes);
7584 return true;
7585 }
7586
7587 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
7588 APSInt AsInt(Val.bitcastToAPInt());
7589 return visitInt(Val: AsInt, Ty, Offset);
7590 }
7591
7592public:
7593 static std::optional<BitCastBuffer>
7594 convert(EvalInfo &Info, const APValue &Src, const CastExpr *BCE) {
7595 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(T: BCE->getType());
7596 APValueToBufferConverter Converter(Info, DstSize, BCE);
7597 if (!Converter.visit(Val: Src, Ty: BCE->getSubExpr()->getType()))
7598 return std::nullopt;
7599 return Converter.Buffer;
7600 }
7601};
7602
7603/// Write an BitCastBuffer into an APValue.
7604class BufferToAPValueConverter {
7605 EvalInfo &Info;
7606 const BitCastBuffer &Buffer;
7607 const CastExpr *BCE;
7608
7609 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
7610 const CastExpr *BCE)
7611 : Info(Info), Buffer(Buffer), BCE(BCE) {}
7612
7613 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
7614 // with an invalid type, so anything left is a deficiency on our part (FIXME).
7615 // Ideally this will be unreachable.
7616 std::nullopt_t unsupportedType(QualType Ty) {
7617 Info.FFDiag(Loc: BCE->getBeginLoc(),
7618 DiagId: diag::note_constexpr_bit_cast_unsupported_type)
7619 << Ty;
7620 return std::nullopt;
7621 }
7622
7623 std::nullopt_t unrepresentableValue(QualType Ty, const APSInt &Val) {
7624 Info.FFDiag(Loc: BCE->getBeginLoc(),
7625 DiagId: diag::note_constexpr_bit_cast_unrepresentable_value)
7626 << Ty << toString(I: Val, /*Radix=*/10);
7627 return std::nullopt;
7628 }
7629
7630 std::optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
7631 const EnumType *EnumSugar = nullptr) {
7632 if (T->isNullPtrType()) {
7633 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QT: QualType(T, 0));
7634 return APValue((Expr *)nullptr,
7635 /*Offset=*/CharUnits::fromQuantity(Quantity: NullValue),
7636 APValue::NoLValuePath{}, /*IsNullPtr=*/true);
7637 }
7638
7639 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
7640
7641 // Work around floating point types that contain unused padding bytes. This
7642 // is really just `long double` on x86, which is the only fundamental type
7643 // with padding bytes.
7644 if (T->isRealFloatingType()) {
7645 const llvm::fltSemantics &Semantics =
7646 Info.Ctx.getFloatTypeSemantics(T: QualType(T, 0));
7647 unsigned NumBits = llvm::APFloatBase::getSizeInBits(Sem: Semantics);
7648 assert(NumBits % 8 == 0);
7649 CharUnits NumBytes = CharUnits::fromQuantity(Quantity: NumBits / 8);
7650 if (NumBytes != SizeOf)
7651 SizeOf = NumBytes;
7652 }
7653
7654 SmallVector<uint8_t, 8> Bytes;
7655 if (!Buffer.readObject(Offset, Width: SizeOf, Output&: Bytes)) {
7656 // If this is std::byte or unsigned char, then its okay to store an
7657 // indeterminate value.
7658 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
7659 bool IsUChar =
7660 !EnumSugar && (T->isSpecificBuiltinType(K: BuiltinType::UChar) ||
7661 T->isSpecificBuiltinType(K: BuiltinType::Char_U));
7662 if (!IsStdByte && !IsUChar) {
7663 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
7664 Info.FFDiag(Loc: BCE->getExprLoc(),
7665 DiagId: diag::note_constexpr_bit_cast_indet_dest)
7666 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
7667 return std::nullopt;
7668 }
7669
7670 return APValue::IndeterminateValue();
7671 }
7672
7673 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
7674 llvm::LoadIntFromMemory(IntVal&: Val, Src: &*Bytes.begin(), LoadBytes: Bytes.size());
7675
7676 if (T->isIntegralOrEnumerationType()) {
7677 Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
7678
7679 unsigned IntWidth = Info.Ctx.getIntWidth(T: QualType(T, 0));
7680 if (IntWidth != Val.getBitWidth()) {
7681 APSInt Truncated = Val.trunc(width: IntWidth);
7682 if (Truncated.extend(width: Val.getBitWidth()) != Val)
7683 return unrepresentableValue(Ty: QualType(T, 0), Val);
7684 Val = Truncated;
7685 }
7686
7687 return APValue(Val);
7688 }
7689
7690 if (T->isRealFloatingType()) {
7691 const llvm::fltSemantics &Semantics =
7692 Info.Ctx.getFloatTypeSemantics(T: QualType(T, 0));
7693 return APValue(APFloat(Semantics, Val));
7694 }
7695
7696 return unsupportedType(Ty: QualType(T, 0));
7697 }
7698
7699 std::optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
7700 const RecordDecl *RD = RTy->getAsRecordDecl();
7701 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
7702
7703 unsigned NumBases = 0;
7704 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD))
7705 NumBases = CXXRD->getNumBases();
7706
7707 APValue ResultVal(APValue::UninitStruct(), NumBases,
7708 std::distance(first: RD->field_begin(), last: RD->field_end()));
7709
7710 // Visit the base classes.
7711 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
7712 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7713 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7714 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7715
7716 std::optional<APValue> SubObj = visitType(
7717 Ty: BS.getType(), Offset: Layout.getBaseClassOffset(Base: BaseDecl) + Offset);
7718 if (!SubObj)
7719 return std::nullopt;
7720 ResultVal.getStructBase(i: I) = *SubObj;
7721 }
7722 }
7723
7724 // Visit the fields.
7725 unsigned FieldIdx = 0;
7726 for (FieldDecl *FD : RD->fields()) {
7727 // FIXME: We don't currently support bit-fields. A lot of the logic for
7728 // this is in CodeGen, so we need to factor it around.
7729 if (FD->isBitField()) {
7730 Info.FFDiag(Loc: BCE->getBeginLoc(),
7731 DiagId: diag::note_constexpr_bit_cast_unsupported_bitfield);
7732 return std::nullopt;
7733 }
7734
7735 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldNo: FieldIdx);
7736 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0);
7737
7738 CharUnits FieldOffset =
7739 CharUnits::fromQuantity(Quantity: FieldOffsetBits / Info.Ctx.getCharWidth()) +
7740 Offset;
7741 QualType FieldTy = FD->getType();
7742 std::optional<APValue> SubObj = visitType(Ty: FieldTy, Offset: FieldOffset);
7743 if (!SubObj)
7744 return std::nullopt;
7745 ResultVal.getStructField(i: FieldIdx) = *SubObj;
7746 ++FieldIdx;
7747 }
7748
7749 return ResultVal;
7750 }
7751
7752 std::optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
7753 QualType RepresentationType = Ty->getDecl()->getIntegerType();
7754 assert(!RepresentationType.isNull() &&
7755 "enum forward decl should be caught by Sema");
7756 const auto *AsBuiltin =
7757 RepresentationType.getCanonicalType()->castAs<BuiltinType>();
7758 // Recurse into the underlying type. Treat std::byte transparently as
7759 // unsigned char.
7760 return visit(T: AsBuiltin, Offset, /*EnumTy=*/EnumSugar: Ty);
7761 }
7762
7763 std::optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
7764 size_t Size = Ty->getLimitedSize();
7765 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(T: Ty->getElementType());
7766
7767 APValue ArrayValue(APValue::UninitArray(), Size, Size);
7768 for (size_t I = 0; I != Size; ++I) {
7769 std::optional<APValue> ElementValue =
7770 visitType(Ty: Ty->getElementType(), Offset: Offset + I * ElementWidth);
7771 if (!ElementValue)
7772 return std::nullopt;
7773 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
7774 }
7775
7776 return ArrayValue;
7777 }
7778
7779 std::optional<APValue> visit(const ComplexType *Ty, CharUnits Offset) {
7780 QualType ElementType = Ty->getElementType();
7781 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(T: ElementType);
7782 bool IsInt = ElementType->isIntegerType();
7783
7784 std::optional<APValue> Values[2];
7785 for (unsigned I = 0; I != 2; ++I) {
7786 Values[I] = visitType(Ty: Ty->getElementType(), Offset: Offset + I * ElementWidth);
7787 if (!Values[I])
7788 return std::nullopt;
7789 }
7790
7791 if (IsInt)
7792 return APValue(Values[0]->getInt(), Values[1]->getInt());
7793 return APValue(Values[0]->getFloat(), Values[1]->getFloat());
7794 }
7795
7796 std::optional<APValue> visit(const VectorType *VTy, CharUnits Offset) {
7797 QualType EltTy = VTy->getElementType();
7798 unsigned NElts = VTy->getNumElements();
7799 unsigned EltSize =
7800 VTy->isPackedVectorBoolType(ctx: Info.Ctx) ? 1 : Info.Ctx.getTypeSize(T: EltTy);
7801
7802 SmallVector<APValue, 4> Elts;
7803 Elts.reserve(N: NElts);
7804 if (VTy->isPackedVectorBoolType(ctx: Info.Ctx)) {
7805 // Special handling for OpenCL bool vectors:
7806 // Since these vectors are stored as packed bits, but we can't read
7807 // individual bits from the BitCastBuffer, we'll buffer all of the
7808 // elements together into an appropriately sized APInt and write them all
7809 // out at once. Because we don't accept vectors where NElts * EltSize
7810 // isn't a multiple of the char size, there will be no padding space, so
7811 // we don't have to worry about reading any padding data which didn't
7812 // actually need to be accessed.
7813 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
7814
7815 SmallVector<uint8_t, 8> Bytes;
7816 Bytes.reserve(N: NElts / 8);
7817 if (!Buffer.readObject(Offset, Width: CharUnits::fromQuantity(Quantity: NElts / 8), Output&: Bytes))
7818 return std::nullopt;
7819
7820 APSInt SValInt(NElts, true);
7821 llvm::LoadIntFromMemory(IntVal&: SValInt, Src: &*Bytes.begin(), LoadBytes: Bytes.size());
7822
7823 for (unsigned I = 0; I < NElts; ++I) {
7824 llvm::APInt Elt =
7825 SValInt.extractBits(numBits: 1, bitPosition: (BigEndian ? NElts - I - 1 : I) * EltSize);
7826 Elts.emplace_back(
7827 Args: APSInt(std::move(Elt), !EltTy->isSignedIntegerType()));
7828 }
7829 } else {
7830 // Iterate over each of the elements and read them from the buffer at
7831 // the appropriate offset.
7832 CharUnits EltSizeChars = Info.Ctx.getTypeSizeInChars(T: EltTy);
7833 for (unsigned I = 0; I < NElts; ++I) {
7834 std::optional<APValue> EltValue =
7835 visitType(Ty: EltTy, Offset: Offset + I * EltSizeChars);
7836 if (!EltValue)
7837 return std::nullopt;
7838 Elts.push_back(Elt: std::move(*EltValue));
7839 }
7840 }
7841
7842 return APValue(Elts.data(), Elts.size());
7843 }
7844
7845 std::optional<APValue> visit(const Type *Ty, CharUnits Offset) {
7846 return unsupportedType(Ty: QualType(Ty, 0));
7847 }
7848
7849 std::optional<APValue> visitType(QualType Ty, CharUnits Offset) {
7850 QualType Can = Ty.getCanonicalType();
7851
7852 switch (Can->getTypeClass()) {
7853#define TYPE(Class, Base) \
7854 case Type::Class: \
7855 return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
7856#define ABSTRACT_TYPE(Class, Base)
7857#define NON_CANONICAL_TYPE(Class, Base) \
7858 case Type::Class: \
7859 llvm_unreachable("non-canonical type should be impossible!");
7860#define DEPENDENT_TYPE(Class, Base) \
7861 case Type::Class: \
7862 llvm_unreachable( \
7863 "dependent types aren't supported in the constant evaluator!");
7864#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \
7865 case Type::Class: \
7866 llvm_unreachable("either dependent or not canonical!");
7867#include "clang/AST/TypeNodes.inc"
7868 }
7869 llvm_unreachable("Unhandled Type::TypeClass");
7870 }
7871
7872public:
7873 // Pull out a full value of type DstType.
7874 static std::optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
7875 const CastExpr *BCE) {
7876 BufferToAPValueConverter Converter(Info, Buffer, BCE);
7877 return Converter.visitType(Ty: BCE->getType(), Offset: CharUnits::fromQuantity(Quantity: 0));
7878 }
7879};
7880
7881static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
7882 QualType Ty, EvalInfo *Info,
7883 const ASTContext &Ctx,
7884 bool CheckingDest) {
7885 Ty = Ty.getCanonicalType();
7886
7887 auto diag = [&](int Reason) {
7888 if (Info)
7889 Info->FFDiag(Loc, DiagId: diag::note_constexpr_bit_cast_invalid_type)
7890 << CheckingDest << (Reason == 4) << Reason;
7891 return false;
7892 };
7893 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
7894 if (Info)
7895 Info->Note(Loc: NoteLoc, DiagId: diag::note_constexpr_bit_cast_invalid_subtype)
7896 << NoteTy << Construct << Ty;
7897 return false;
7898 };
7899
7900 if (Ty->isUnionType())
7901 return diag(0);
7902 if (Ty->isPointerType())
7903 return diag(1);
7904 if (Ty->isMemberPointerType())
7905 return diag(2);
7906 if (Ty.isVolatileQualified())
7907 return diag(3);
7908
7909 if (RecordDecl *Record = Ty->getAsRecordDecl()) {
7910 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: Record)) {
7911 for (CXXBaseSpecifier &BS : CXXRD->bases())
7912 if (!checkBitCastConstexprEligibilityType(Loc, Ty: BS.getType(), Info, Ctx,
7913 CheckingDest))
7914 return note(1, BS.getType(), BS.getBeginLoc());
7915 }
7916 for (FieldDecl *FD : Record->fields()) {
7917 if (FD->getType()->isReferenceType())
7918 return diag(4);
7919 if (!checkBitCastConstexprEligibilityType(Loc, Ty: FD->getType(), Info, Ctx,
7920 CheckingDest))
7921 return note(0, FD->getType(), FD->getBeginLoc());
7922 }
7923 }
7924
7925 if (Ty->isArrayType() &&
7926 !checkBitCastConstexprEligibilityType(Loc, Ty: Ctx.getBaseElementType(QT: Ty),
7927 Info, Ctx, CheckingDest))
7928 return false;
7929
7930 if (const auto *VTy = Ty->getAs<VectorType>()) {
7931 QualType EltTy = VTy->getElementType();
7932 unsigned NElts = VTy->getNumElements();
7933 unsigned EltSize =
7934 VTy->isPackedVectorBoolType(ctx: Ctx) ? 1 : Ctx.getTypeSize(T: EltTy);
7935
7936 if ((NElts * EltSize) % Ctx.getCharWidth() != 0) {
7937 // The vector's size in bits is not a multiple of the target's byte size,
7938 // so its layout is unspecified. For now, we'll simply treat these cases
7939 // as unsupported (this should only be possible with OpenCL bool vectors
7940 // whose element count isn't a multiple of the byte size).
7941 Info->FFDiag(Loc, DiagId: diag::note_constexpr_bit_cast_invalid_vector)
7942 << QualType(VTy, 0) << EltSize << NElts << Ctx.getCharWidth();
7943 return false;
7944 }
7945
7946 if (EltTy->isRealFloatingType() &&
7947 &Ctx.getFloatTypeSemantics(T: EltTy) == &APFloat::x87DoubleExtended()) {
7948 // The layout for x86_fp80 vectors seems to be handled very inconsistently
7949 // by both clang and LLVM, so for now we won't allow bit_casts involving
7950 // it in a constexpr context.
7951 Info->FFDiag(Loc, DiagId: diag::note_constexpr_bit_cast_unsupported_type)
7952 << EltTy;
7953 return false;
7954 }
7955 }
7956
7957 return true;
7958}
7959
7960static bool checkBitCastConstexprEligibility(EvalInfo *Info,
7961 const ASTContext &Ctx,
7962 const CastExpr *BCE) {
7963 bool DestOK = checkBitCastConstexprEligibilityType(
7964 Loc: BCE->getBeginLoc(), Ty: BCE->getType(), Info, Ctx, CheckingDest: true);
7965 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
7966 Loc: BCE->getBeginLoc(),
7967 Ty: BCE->getSubExpr()->getType(), Info, Ctx, CheckingDest: false);
7968 return SourceOK;
7969}
7970
7971static bool handleRValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7972 const APValue &SourceRValue,
7973 const CastExpr *BCE) {
7974 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
7975 "no host or target supports non 8-bit chars");
7976
7977 if (!checkBitCastConstexprEligibility(Info: &Info, Ctx: Info.Ctx, BCE))
7978 return false;
7979
7980 // Read out SourceValue into a char buffer.
7981 std::optional<BitCastBuffer> Buffer =
7982 APValueToBufferConverter::convert(Info, Src: SourceRValue, BCE);
7983 if (!Buffer)
7984 return false;
7985
7986 // Write out the buffer into a new APValue.
7987 std::optional<APValue> MaybeDestValue =
7988 BufferToAPValueConverter::convert(Info, Buffer&: *Buffer, BCE);
7989 if (!MaybeDestValue)
7990 return false;
7991
7992 DestValue = std::move(*MaybeDestValue);
7993 return true;
7994}
7995
7996static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7997 APValue &SourceValue,
7998 const CastExpr *BCE) {
7999 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
8000 "no host or target supports non 8-bit chars");
8001 assert(SourceValue.isLValue() &&
8002 "LValueToRValueBitcast requires an lvalue operand!");
8003
8004 LValue SourceLValue;
8005 APValue SourceRValue;
8006 SourceLValue.setFrom(Ctx&: Info.Ctx, V: SourceValue);
8007 if (!handleLValueToRValueConversion(
8008 Info, Conv: BCE, Type: BCE->getSubExpr()->getType().withConst(), LVal: SourceLValue,
8009 RVal&: SourceRValue, /*WantObjectRepresentation=*/true))
8010 return false;
8011
8012 return handleRValueToRValueBitCast(Info, DestValue, SourceRValue, BCE);
8013}
8014
8015template <class Derived>
8016class ExprEvaluatorBase
8017 : public ConstStmtVisitor<Derived, bool> {
8018private:
8019 Derived &getDerived() { return static_cast<Derived&>(*this); }
8020 bool DerivedSuccess(const APValue &V, const Expr *E) {
8021 return getDerived().Success(V, E);
8022 }
8023 bool DerivedZeroInitialization(const Expr *E) {
8024 return getDerived().ZeroInitialization(E);
8025 }
8026
8027 // Check whether a conditional operator with a non-constant condition is a
8028 // potential constant expression. If neither arm is a potential constant
8029 // expression, then the conditional operator is not either.
8030 template<typename ConditionalOperator>
8031 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
8032 assert(Info.checkingPotentialConstantExpression());
8033
8034 // Speculatively evaluate both arms.
8035 SmallVector<PartialDiagnosticAt, 8> Diag;
8036 {
8037 SpeculativeEvaluationRAII Speculate(Info, &Diag);
8038 StmtVisitorTy::Visit(E->getFalseExpr());
8039 if (Diag.empty())
8040 return;
8041 }
8042
8043 {
8044 SpeculativeEvaluationRAII Speculate(Info, &Diag);
8045 Diag.clear();
8046 StmtVisitorTy::Visit(E->getTrueExpr());
8047 if (Diag.empty())
8048 return;
8049 }
8050
8051 Error(E, diag::note_constexpr_conditional_never_const);
8052 }
8053
8054
8055 template<typename ConditionalOperator>
8056 bool HandleConditionalOperator(const ConditionalOperator *E) {
8057 bool BoolResult;
8058 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
8059 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
8060 CheckPotentialConstantConditional(E);
8061 return false;
8062 }
8063 if (Info.noteFailure()) {
8064 StmtVisitorTy::Visit(E->getTrueExpr());
8065 StmtVisitorTy::Visit(E->getFalseExpr());
8066 }
8067 return false;
8068 }
8069
8070 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
8071 return StmtVisitorTy::Visit(EvalExpr);
8072 }
8073
8074protected:
8075 EvalInfo &Info;
8076 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
8077 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
8078
8079 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
8080 return Info.CCEDiag(E, DiagId: D);
8081 }
8082
8083 bool ZeroInitialization(const Expr *E) { return Error(E); }
8084
8085 bool IsConstantEvaluatedBuiltinCall(const CallExpr *E) {
8086 unsigned BuiltinOp = E->getBuiltinCallee();
8087 return BuiltinOp != 0 &&
8088 Info.Ctx.BuiltinInfo.isConstantEvaluated(ID: BuiltinOp);
8089 }
8090
8091public:
8092 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
8093
8094 EvalInfo &getEvalInfo() { return Info; }
8095
8096 /// Report an evaluation error. This should only be called when an error is
8097 /// first discovered. When propagating an error, just return false.
8098 bool Error(const Expr *E, diag::kind D) {
8099 Info.FFDiag(E, DiagId: D) << E->getSourceRange();
8100 return false;
8101 }
8102 bool Error(const Expr *E) {
8103 return Error(E, diag::note_invalid_subexpr_in_const_expr);
8104 }
8105
8106 bool VisitStmt(const Stmt *) {
8107 llvm_unreachable("Expression evaluator should not be called on stmts");
8108 }
8109 bool VisitExpr(const Expr *E) {
8110 return Error(E);
8111 }
8112
8113 bool VisitEmbedExpr(const EmbedExpr *E) {
8114 const auto It = E->begin();
8115 return StmtVisitorTy::Visit(*It);
8116 }
8117
8118 bool VisitPredefinedExpr(const PredefinedExpr *E) {
8119 return StmtVisitorTy::Visit(E->getFunctionName());
8120 }
8121 bool VisitConstantExpr(const ConstantExpr *E) {
8122 if (E->hasAPValueResult())
8123 return DerivedSuccess(V: E->getAPValueResult(), E);
8124
8125 return StmtVisitorTy::Visit(E->getSubExpr());
8126 }
8127
8128 bool VisitParenExpr(const ParenExpr *E)
8129 { return StmtVisitorTy::Visit(E->getSubExpr()); }
8130 bool VisitUnaryExtension(const UnaryOperator *E)
8131 { return StmtVisitorTy::Visit(E->getSubExpr()); }
8132 bool VisitUnaryPlus(const UnaryOperator *E)
8133 { return StmtVisitorTy::Visit(E->getSubExpr()); }
8134 bool VisitChooseExpr(const ChooseExpr *E)
8135 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
8136 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
8137 { return StmtVisitorTy::Visit(E->getResultExpr()); }
8138 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
8139 { return StmtVisitorTy::Visit(E->getReplacement()); }
8140 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
8141 TempVersionRAII RAII(*Info.CurrentCall);
8142 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
8143 return StmtVisitorTy::Visit(E->getExpr());
8144 }
8145 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
8146 TempVersionRAII RAII(*Info.CurrentCall);
8147 // The initializer may not have been parsed yet, or might be erroneous.
8148 if (!E->getExpr())
8149 return Error(E);
8150 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
8151 return StmtVisitorTy::Visit(E->getExpr());
8152 }
8153
8154 bool VisitExprWithCleanups(const ExprWithCleanups *E) {
8155 FullExpressionRAII Scope(Info);
8156 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
8157 }
8158
8159 // Temporaries are registered when created, so we don't care about
8160 // CXXBindTemporaryExpr.
8161 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
8162 return StmtVisitorTy::Visit(E->getSubExpr());
8163 }
8164
8165 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
8166 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
8167 << diag::ConstexprInvalidCastKind::Reinterpret;
8168 return static_cast<Derived*>(this)->VisitCastExpr(E);
8169 }
8170 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
8171 if (!Info.Ctx.getLangOpts().CPlusPlus20)
8172 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
8173 << diag::ConstexprInvalidCastKind::Dynamic;
8174 return static_cast<Derived*>(this)->VisitCastExpr(E);
8175 }
8176 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
8177 return static_cast<Derived*>(this)->VisitCastExpr(E);
8178 }
8179
8180 bool VisitBinaryOperator(const BinaryOperator *E) {
8181 switch (E->getOpcode()) {
8182 default:
8183 return Error(E);
8184
8185 case BO_Comma:
8186 VisitIgnoredValue(E: E->getLHS());
8187 return StmtVisitorTy::Visit(E->getRHS());
8188
8189 case BO_PtrMemD:
8190 case BO_PtrMemI: {
8191 LValue Obj;
8192 if (!HandleMemberPointerAccess(Info, BO: E, LV&: Obj))
8193 return false;
8194 APValue Result;
8195 if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getType(), LVal: Obj, RVal&: Result))
8196 return false;
8197 return DerivedSuccess(V: Result, E);
8198 }
8199 }
8200 }
8201
8202 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
8203 return StmtVisitorTy::Visit(E->getSemanticForm());
8204 }
8205
8206 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
8207 // Evaluate and cache the common expression. We treat it as a temporary,
8208 // even though it's not quite the same thing.
8209 LValue CommonLV;
8210 if (!Evaluate(Result&: Info.CurrentCall->createTemporary(
8211 Key: E->getOpaqueValue(),
8212 T: getStorageType(Ctx: Info.Ctx, E: E->getOpaqueValue()),
8213 Scope: ScopeKind::FullExpression, LV&: CommonLV),
8214 Info, E: E->getCommon()))
8215 return false;
8216
8217 return HandleConditionalOperator(E);
8218 }
8219
8220 bool VisitConditionalOperator(const ConditionalOperator *E) {
8221 bool IsBcpCall = false;
8222 // If the condition (ignoring parens) is a __builtin_constant_p call,
8223 // the result is a constant expression if it can be folded without
8224 // side-effects. This is an important GNU extension. See GCC PR38377
8225 // for discussion.
8226 if (const CallExpr *CallCE =
8227 dyn_cast<CallExpr>(Val: E->getCond()->IgnoreParenCasts()))
8228 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
8229 IsBcpCall = true;
8230
8231 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
8232 // constant expression; we can't check whether it's potentially foldable.
8233 // FIXME: We should instead treat __builtin_constant_p as non-constant if
8234 // it would return 'false' in this mode.
8235 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
8236 return false;
8237
8238 FoldConstant Fold(Info, IsBcpCall);
8239 if (!HandleConditionalOperator(E)) {
8240 Fold.keepDiagnostics();
8241 return false;
8242 }
8243
8244 return true;
8245 }
8246
8247 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
8248 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(Key: E);
8249 Value && !Value->isAbsent())
8250 return DerivedSuccess(V: *Value, E);
8251
8252 const Expr *Source = E->getSourceExpr();
8253 if (!Source)
8254 return Error(E);
8255 if (Source == E) {
8256 assert(0 && "OpaqueValueExpr recursively refers to itself");
8257 return Error(E);
8258 }
8259 return StmtVisitorTy::Visit(Source);
8260 }
8261
8262 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
8263 for (const Expr *SemE : E->semantics()) {
8264 if (auto *OVE = dyn_cast<OpaqueValueExpr>(Val: SemE)) {
8265 // FIXME: We can't handle the case where an OpaqueValueExpr is also the
8266 // result expression: there could be two different LValues that would
8267 // refer to the same object in that case, and we can't model that.
8268 if (SemE == E->getResultExpr())
8269 return Error(E);
8270
8271 // Unique OVEs get evaluated if and when we encounter them when
8272 // emitting the rest of the semantic form, rather than eagerly.
8273 if (OVE->isUnique())
8274 continue;
8275
8276 LValue LV;
8277 if (!Evaluate(Result&: Info.CurrentCall->createTemporary(
8278 Key: OVE, T: getStorageType(Ctx: Info.Ctx, E: OVE),
8279 Scope: ScopeKind::FullExpression, LV),
8280 Info, E: OVE->getSourceExpr()))
8281 return false;
8282 } else if (SemE == E->getResultExpr()) {
8283 if (!StmtVisitorTy::Visit(SemE))
8284 return false;
8285 } else {
8286 if (!EvaluateIgnoredValue(Info, E: SemE))
8287 return false;
8288 }
8289 }
8290 return true;
8291 }
8292
8293 bool VisitCallExpr(const CallExpr *E) {
8294 APValue Result;
8295 if (!handleCallExpr(E, Result, ResultSlot: nullptr))
8296 return false;
8297 return DerivedSuccess(V: Result, E);
8298 }
8299
8300 bool handleCallExpr(const CallExpr *E, APValue &Result,
8301 const LValue *ResultSlot) {
8302 CallScopeRAII CallScope(Info);
8303
8304 const Expr *Callee = E->getCallee()->IgnoreParens();
8305 QualType CalleeType = Callee->getType();
8306
8307 const FunctionDecl *FD = nullptr;
8308 LValue *This = nullptr, ObjectArg;
8309 auto Args = ArrayRef(E->getArgs(), E->getNumArgs());
8310 bool HasQualifier = false;
8311
8312 CallRef Call;
8313
8314 // Extract function decl and 'this' pointer from the callee.
8315 if (CalleeType->isSpecificBuiltinType(K: BuiltinType::BoundMember)) {
8316 const CXXMethodDecl *Member = nullptr;
8317 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Val: Callee)) {
8318 // Explicit bound member calls, such as x.f() or p->g();
8319 if (!EvaluateObjectArgument(Info, Object: ME->getBase(), This&: ObjectArg))
8320 return false;
8321 Member = dyn_cast<CXXMethodDecl>(Val: ME->getMemberDecl());
8322 if (!Member)
8323 return Error(Callee);
8324 This = &ObjectArg;
8325 HasQualifier = ME->hasQualifier();
8326 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Val: Callee)) {
8327 // Indirect bound member calls ('.*' or '->*').
8328 const ValueDecl *D =
8329 HandleMemberPointerAccess(Info, BO: BE, LV&: ObjectArg, IncludeMember: false);
8330 if (!D)
8331 return false;
8332 Member = dyn_cast<CXXMethodDecl>(Val: D);
8333 if (!Member)
8334 return Error(Callee);
8335 This = &ObjectArg;
8336 } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Val: Callee)) {
8337 if (!Info.getLangOpts().CPlusPlus20)
8338 Info.CCEDiag(E: PDE, DiagId: diag::note_constexpr_pseudo_destructor);
8339 return EvaluateObjectArgument(Info, Object: PDE->getBase(), This&: ObjectArg) &&
8340 HandleDestruction(Info, E: PDE, This: ObjectArg, ThisType: PDE->getDestroyedType());
8341 } else
8342 return Error(Callee);
8343 FD = Member;
8344 } else if (CalleeType->isFunctionPointerType()) {
8345 LValue CalleeLV;
8346 if (!EvaluatePointer(E: Callee, Result&: CalleeLV, Info))
8347 return false;
8348
8349 if (!CalleeLV.getLValueOffset().isZero())
8350 return Error(Callee);
8351 if (CalleeLV.isNullPointer()) {
8352 Info.FFDiag(E: Callee, DiagId: diag::note_constexpr_null_callee)
8353 << const_cast<Expr *>(Callee);
8354 return false;
8355 }
8356 FD = dyn_cast_or_null<FunctionDecl>(
8357 Val: CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>());
8358 if (!FD)
8359 return Error(Callee);
8360 // Don't call function pointers which have been cast to some other type.
8361 // Per DR (no number yet), the caller and callee can differ in noexcept.
8362 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
8363 T: CalleeType->getPointeeType(), U: FD->getType())) {
8364 return Error(E);
8365 }
8366
8367 // For an (overloaded) assignment expression, evaluate the RHS before the
8368 // LHS.
8369 auto *OCE = dyn_cast<CXXOperatorCallExpr>(Val: E);
8370 if (OCE && OCE->isAssignmentOp()) {
8371 assert(Args.size() == 2 && "wrong number of arguments in assignment");
8372 Call = Info.CurrentCall->createCall(Callee: FD);
8373 bool HasThis = false;
8374 if (const auto *MD = dyn_cast<CXXMethodDecl>(Val: FD))
8375 HasThis = MD->isImplicitObjectMemberFunction();
8376 if (!EvaluateArgs(Args: HasThis ? Args.slice(N: 1) : Args, Call, Info, Callee: FD,
8377 /*RightToLeft=*/true, ObjectArg: &ObjectArg))
8378 return false;
8379 }
8380
8381 // Overloaded operator calls to member functions are represented as normal
8382 // calls with '*this' as the first argument.
8383 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: FD);
8384 if (MD &&
8385 (MD->isImplicitObjectMemberFunction() || (OCE && MD->isStatic()))) {
8386 // FIXME: When selecting an implicit conversion for an overloaded
8387 // operator delete, we sometimes try to evaluate calls to conversion
8388 // operators without a 'this' parameter!
8389 if (Args.empty())
8390 return Error(E);
8391
8392 if (!EvaluateObjectArgument(Info, Object: Args[0], This&: ObjectArg))
8393 return false;
8394
8395 // If we are calling a static operator, the 'this' argument needs to be
8396 // ignored after being evaluated.
8397 if (MD->isInstance())
8398 This = &ObjectArg;
8399
8400 // If this is syntactically a simple assignment using a trivial
8401 // assignment operator, start the lifetimes of union members as needed,
8402 // per C++20 [class.union]5.
8403 if (Info.getLangOpts().CPlusPlus20 && OCE &&
8404 OCE->getOperator() == OO_Equal && MD->isTrivial() &&
8405 !MaybeHandleUnionActiveMemberChange(Info, LHSExpr: Args[0], LHS: ObjectArg))
8406 return false;
8407
8408 Args = Args.slice(N: 1);
8409 } else if (MD && MD->isLambdaStaticInvoker()) {
8410 // Map the static invoker for the lambda back to the call operator.
8411 // Conveniently, we don't have to slice out the 'this' argument (as is
8412 // being done for the non-static case), since a static member function
8413 // doesn't have an implicit argument passed in.
8414 const CXXRecordDecl *ClosureClass = MD->getParent();
8415 assert(
8416 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
8417 "Number of captures must be zero for conversion to function-ptr");
8418
8419 const CXXMethodDecl *LambdaCallOp =
8420 ClosureClass->getLambdaCallOperator();
8421
8422 // Set 'FD', the function that will be called below, to the call
8423 // operator. If the closure object represents a generic lambda, find
8424 // the corresponding specialization of the call operator.
8425
8426 if (ClosureClass->isGenericLambda()) {
8427 assert(MD->isFunctionTemplateSpecialization() &&
8428 "A generic lambda's static-invoker function must be a "
8429 "template specialization");
8430 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
8431 FunctionTemplateDecl *CallOpTemplate =
8432 LambdaCallOp->getDescribedFunctionTemplate();
8433 void *InsertPos = nullptr;
8434 FunctionDecl *CorrespondingCallOpSpecialization =
8435 CallOpTemplate->findSpecialization(Args: TAL->asArray(), InsertPos);
8436 assert(CorrespondingCallOpSpecialization &&
8437 "We must always have a function call operator specialization "
8438 "that corresponds to our static invoker specialization");
8439 assert(isa<CXXMethodDecl>(CorrespondingCallOpSpecialization));
8440 FD = CorrespondingCallOpSpecialization;
8441 } else
8442 FD = LambdaCallOp;
8443 } else if (FD->isUsableAsGlobalAllocationFunctionInConstantEvaluation()) {
8444 if (FD->getDeclName().isAnyOperatorNew()) {
8445 LValue Ptr;
8446 if (!HandleOperatorNewCall(Info, E, Result&: Ptr))
8447 return false;
8448 Ptr.moveInto(V&: Result);
8449 return CallScope.destroy();
8450 } else {
8451 return HandleOperatorDeleteCall(Info, E) && CallScope.destroy();
8452 }
8453 }
8454 } else
8455 return Error(E);
8456
8457 // Evaluate the arguments now if we've not already done so.
8458 if (!Call) {
8459 Call = Info.CurrentCall->createCall(Callee: FD);
8460 if (!EvaluateArgs(Args, Call, Info, Callee: FD, /*RightToLeft*/ false,
8461 ObjectArg: &ObjectArg))
8462 return false;
8463 }
8464
8465 SmallVector<QualType, 4> CovariantAdjustmentPath;
8466 if (This) {
8467 auto *NamedMember = dyn_cast<CXXMethodDecl>(Val: FD);
8468 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
8469 // Perform virtual dispatch, if necessary.
8470 FD = HandleVirtualDispatch(Info, E, This&: *This, Found: NamedMember,
8471 CovariantAdjustmentPath);
8472 if (!FD)
8473 return false;
8474 } else if (NamedMember && NamedMember->isImplicitObjectMemberFunction()) {
8475 // Check that the 'this' pointer points to an object of the right type.
8476 // FIXME: If this is an assignment operator call, we may need to change
8477 // the active union member before we check this.
8478 if (!checkNonVirtualMemberCallThisPointer(Info, E, This: *This, NamedMember))
8479 return false;
8480 }
8481 }
8482
8483 // Destructor calls are different enough that they have their own codepath.
8484 if (auto *DD = dyn_cast<CXXDestructorDecl>(Val: FD)) {
8485 assert(This && "no 'this' pointer for destructor call");
8486 return HandleDestruction(Info, E, This: *This,
8487 ThisType: Info.Ctx.getRecordType(Decl: DD->getParent())) &&
8488 CallScope.destroy();
8489 }
8490
8491 const FunctionDecl *Definition = nullptr;
8492 Stmt *Body = FD->getBody(Definition);
8493 SourceLocation Loc = E->getExprLoc();
8494
8495 // Treat the object argument as `this` when evaluating defaulted
8496 // special menmber functions
8497 if (FD->hasCXXExplicitFunctionObjectParameter())
8498 This = &ObjectArg;
8499
8500 if (!CheckConstexprFunction(Info, CallLoc: Loc, Declaration: FD, Definition, Body) ||
8501 !HandleFunctionCall(CallLoc: Loc, Callee: Definition, ObjectArg: This, E, Args, Call, Body, Info,
8502 Result, ResultSlot))
8503 return false;
8504
8505 if (!CovariantAdjustmentPath.empty() &&
8506 !HandleCovariantReturnAdjustment(Info, E, Result,
8507 Path: CovariantAdjustmentPath))
8508 return false;
8509
8510 return CallScope.destroy();
8511 }
8512
8513 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
8514 return StmtVisitorTy::Visit(E->getInitializer());
8515 }
8516 bool VisitInitListExpr(const InitListExpr *E) {
8517 if (E->getNumInits() == 0)
8518 return DerivedZeroInitialization(E);
8519 if (E->getNumInits() == 1)
8520 return StmtVisitorTy::Visit(E->getInit(Init: 0));
8521 return Error(E);
8522 }
8523 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
8524 return DerivedZeroInitialization(E);
8525 }
8526 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
8527 return DerivedZeroInitialization(E);
8528 }
8529 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
8530 return DerivedZeroInitialization(E);
8531 }
8532
8533 /// A member expression where the object is a prvalue is itself a prvalue.
8534 bool VisitMemberExpr(const MemberExpr *E) {
8535 assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&
8536 "missing temporary materialization conversion");
8537 assert(!E->isArrow() && "missing call to bound member function?");
8538
8539 APValue Val;
8540 if (!Evaluate(Result&: Val, Info, E: E->getBase()))
8541 return false;
8542
8543 QualType BaseTy = E->getBase()->getType();
8544
8545 const FieldDecl *FD = dyn_cast<FieldDecl>(Val: E->getMemberDecl());
8546 if (!FD) return Error(E);
8547 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
8548 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
8549 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
8550
8551 // Note: there is no lvalue base here. But this case should only ever
8552 // happen in C or in C++98, where we cannot be evaluating a constexpr
8553 // constructor, which is the only case the base matters.
8554 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
8555 SubobjectDesignator Designator(BaseTy);
8556 Designator.addDeclUnchecked(D: FD);
8557
8558 APValue Result;
8559 return extractSubobject(Info, E, Obj, Sub: Designator, Result) &&
8560 DerivedSuccess(V: Result, E);
8561 }
8562
8563 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
8564 APValue Val;
8565 if (!Evaluate(Result&: Val, Info, E: E->getBase()))
8566 return false;
8567
8568 if (Val.isVector()) {
8569 SmallVector<uint32_t, 4> Indices;
8570 E->getEncodedElementAccess(Elts&: Indices);
8571 if (Indices.size() == 1) {
8572 // Return scalar.
8573 return DerivedSuccess(V: Val.getVectorElt(I: Indices[0]), E);
8574 } else {
8575 // Construct new APValue vector.
8576 SmallVector<APValue, 4> Elts;
8577 for (unsigned I = 0; I < Indices.size(); ++I) {
8578 Elts.push_back(Elt: Val.getVectorElt(I: Indices[I]));
8579 }
8580 APValue VecResult(Elts.data(), Indices.size());
8581 return DerivedSuccess(V: VecResult, E);
8582 }
8583 }
8584
8585 return false;
8586 }
8587
8588 bool VisitCastExpr(const CastExpr *E) {
8589 switch (E->getCastKind()) {
8590 default:
8591 break;
8592
8593 case CK_AtomicToNonAtomic: {
8594 APValue AtomicVal;
8595 // This does not need to be done in place even for class/array types:
8596 // atomic-to-non-atomic conversion implies copying the object
8597 // representation.
8598 if (!Evaluate(Result&: AtomicVal, Info, E: E->getSubExpr()))
8599 return false;
8600 return DerivedSuccess(V: AtomicVal, E);
8601 }
8602
8603 case CK_NoOp:
8604 case CK_UserDefinedConversion:
8605 return StmtVisitorTy::Visit(E->getSubExpr());
8606
8607 case CK_LValueToRValue: {
8608 LValue LVal;
8609 if (!EvaluateLValue(E: E->getSubExpr(), Result&: LVal, Info))
8610 return false;
8611 APValue RVal;
8612 // Note, we use the subexpression's type in order to retain cv-qualifiers.
8613 if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getSubExpr()->getType(),
8614 LVal, RVal))
8615 return false;
8616 return DerivedSuccess(V: RVal, E);
8617 }
8618 case CK_LValueToRValueBitCast: {
8619 APValue DestValue, SourceValue;
8620 if (!Evaluate(Result&: SourceValue, Info, E: E->getSubExpr()))
8621 return false;
8622 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, BCE: E))
8623 return false;
8624 return DerivedSuccess(V: DestValue, E);
8625 }
8626
8627 case CK_AddressSpaceConversion: {
8628 APValue Value;
8629 if (!Evaluate(Result&: Value, Info, E: E->getSubExpr()))
8630 return false;
8631 return DerivedSuccess(V: Value, E);
8632 }
8633 }
8634
8635 return Error(E);
8636 }
8637
8638 bool VisitUnaryPostInc(const UnaryOperator *UO) {
8639 return VisitUnaryPostIncDec(UO);
8640 }
8641 bool VisitUnaryPostDec(const UnaryOperator *UO) {
8642 return VisitUnaryPostIncDec(UO);
8643 }
8644 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
8645 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8646 return Error(UO);
8647
8648 LValue LVal;
8649 if (!EvaluateLValue(E: UO->getSubExpr(), Result&: LVal, Info))
8650 return false;
8651 APValue RVal;
8652 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
8653 UO->isIncrementOp(), &RVal))
8654 return false;
8655 return DerivedSuccess(V: RVal, E: UO);
8656 }
8657
8658 bool VisitStmtExpr(const StmtExpr *E) {
8659 // We will have checked the full-expressions inside the statement expression
8660 // when they were completed, and don't need to check them again now.
8661 llvm::SaveAndRestore NotCheckingForUB(Info.CheckingForUndefinedBehavior,
8662 false);
8663
8664 const CompoundStmt *CS = E->getSubStmt();
8665 if (CS->body_empty())
8666 return true;
8667
8668 BlockScopeRAII Scope(Info);
8669 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
8670 BE = CS->body_end();
8671 /**/; ++BI) {
8672 if (BI + 1 == BE) {
8673 const Expr *FinalExpr = dyn_cast<Expr>(Val: *BI);
8674 if (!FinalExpr) {
8675 Info.FFDiag(Loc: (*BI)->getBeginLoc(),
8676 DiagId: diag::note_constexpr_stmt_expr_unsupported);
8677 return false;
8678 }
8679 return this->Visit(FinalExpr) && Scope.destroy();
8680 }
8681
8682 APValue ReturnValue;
8683 StmtResult Result = { .Value: ReturnValue, .Slot: nullptr };
8684 EvalStmtResult ESR = EvaluateStmt(Result, Info, S: *BI);
8685 if (ESR != ESR_Succeeded) {
8686 // FIXME: If the statement-expression terminated due to 'return',
8687 // 'break', or 'continue', it would be nice to propagate that to
8688 // the outer statement evaluation rather than bailing out.
8689 if (ESR != ESR_Failed)
8690 Info.FFDiag(Loc: (*BI)->getBeginLoc(),
8691 DiagId: diag::note_constexpr_stmt_expr_unsupported);
8692 return false;
8693 }
8694 }
8695
8696 llvm_unreachable("Return from function from the loop above.");
8697 }
8698
8699 bool VisitPackIndexingExpr(const PackIndexingExpr *E) {
8700 return StmtVisitorTy::Visit(E->getSelectedExpr());
8701 }
8702
8703 /// Visit a value which is evaluated, but whose value is ignored.
8704 void VisitIgnoredValue(const Expr *E) {
8705 EvaluateIgnoredValue(Info, E);
8706 }
8707
8708 /// Potentially visit a MemberExpr's base expression.
8709 void VisitIgnoredBaseExpression(const Expr *E) {
8710 // While MSVC doesn't evaluate the base expression, it does diagnose the
8711 // presence of side-effecting behavior.
8712 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Ctx: Info.Ctx))
8713 return;
8714 VisitIgnoredValue(E);
8715 }
8716};
8717
8718} // namespace
8719
8720//===----------------------------------------------------------------------===//
8721// Common base class for lvalue and temporary evaluation.
8722//===----------------------------------------------------------------------===//
8723namespace {
8724template<class Derived>
8725class LValueExprEvaluatorBase
8726 : public ExprEvaluatorBase<Derived> {
8727protected:
8728 LValue &Result;
8729 bool InvalidBaseOK;
8730 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
8731 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
8732
8733 bool Success(APValue::LValueBase B) {
8734 Result.set(B);
8735 return true;
8736 }
8737
8738 bool evaluatePointer(const Expr *E, LValue &Result) {
8739 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
8740 }
8741
8742public:
8743 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
8744 : ExprEvaluatorBaseTy(Info), Result(Result),
8745 InvalidBaseOK(InvalidBaseOK) {}
8746
8747 bool Success(const APValue &V, const Expr *E) {
8748 Result.setFrom(Ctx&: this->Info.Ctx, V);
8749 return true;
8750 }
8751
8752 bool VisitMemberExpr(const MemberExpr *E) {
8753 // Handle non-static data members.
8754 QualType BaseTy;
8755 bool EvalOK;
8756 if (E->isArrow()) {
8757 EvalOK = evaluatePointer(E: E->getBase(), Result);
8758 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
8759 } else if (E->getBase()->isPRValue()) {
8760 assert(E->getBase()->getType()->isRecordType());
8761 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
8762 BaseTy = E->getBase()->getType();
8763 } else {
8764 EvalOK = this->Visit(E->getBase());
8765 BaseTy = E->getBase()->getType();
8766 }
8767 if (!EvalOK) {
8768 if (!InvalidBaseOK)
8769 return false;
8770 Result.setInvalid(B: E);
8771 return true;
8772 }
8773
8774 const ValueDecl *MD = E->getMemberDecl();
8775 if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: E->getMemberDecl())) {
8776 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
8777 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
8778 (void)BaseTy;
8779 if (!HandleLValueMember(this->Info, E, Result, FD))
8780 return false;
8781 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(Val: MD)) {
8782 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
8783 return false;
8784 } else
8785 return this->Error(E);
8786
8787 if (MD->getType()->isReferenceType()) {
8788 APValue RefValue;
8789 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
8790 RefValue))
8791 return false;
8792 return Success(RefValue, E);
8793 }
8794 return true;
8795 }
8796
8797 bool VisitBinaryOperator(const BinaryOperator *E) {
8798 switch (E->getOpcode()) {
8799 default:
8800 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8801
8802 case BO_PtrMemD:
8803 case BO_PtrMemI:
8804 return HandleMemberPointerAccess(this->Info, E, Result);
8805 }
8806 }
8807
8808 bool VisitCastExpr(const CastExpr *E) {
8809 switch (E->getCastKind()) {
8810 default:
8811 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8812
8813 case CK_DerivedToBase:
8814 case CK_UncheckedDerivedToBase:
8815 if (!this->Visit(E->getSubExpr()))
8816 return false;
8817
8818 // Now figure out the necessary offset to add to the base LV to get from
8819 // the derived class to the base class.
8820 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
8821 Result);
8822 }
8823 }
8824};
8825}
8826
8827//===----------------------------------------------------------------------===//
8828// LValue Evaluation
8829//
8830// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
8831// function designators (in C), decl references to void objects (in C), and
8832// temporaries (if building with -Wno-address-of-temporary).
8833//
8834// LValue evaluation produces values comprising a base expression of one of the
8835// following types:
8836// - Declarations
8837// * VarDecl
8838// * FunctionDecl
8839// - Literals
8840// * CompoundLiteralExpr in C (and in global scope in C++)
8841// * StringLiteral
8842// * PredefinedExpr
8843// * ObjCStringLiteralExpr
8844// * ObjCEncodeExpr
8845// * AddrLabelExpr
8846// * BlockExpr
8847// * CallExpr for a MakeStringConstant builtin
8848// - typeid(T) expressions, as TypeInfoLValues
8849// - Locals and temporaries
8850// * MaterializeTemporaryExpr
8851// * Any Expr, with a CallIndex indicating the function in which the temporary
8852// was evaluated, for cases where the MaterializeTemporaryExpr is missing
8853// from the AST (FIXME).
8854// * A MaterializeTemporaryExpr that has static storage duration, with no
8855// CallIndex, for a lifetime-extended temporary.
8856// * The ConstantExpr that is currently being evaluated during evaluation of an
8857// immediate invocation.
8858// plus an offset in bytes.
8859//===----------------------------------------------------------------------===//
8860namespace {
8861class LValueExprEvaluator
8862 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
8863public:
8864 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
8865 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
8866
8867 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
8868 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
8869
8870 bool VisitCallExpr(const CallExpr *E);
8871 bool VisitDeclRefExpr(const DeclRefExpr *E);
8872 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(B: E); }
8873 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
8874 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
8875 bool VisitMemberExpr(const MemberExpr *E);
8876 bool VisitStringLiteral(const StringLiteral *E) {
8877 return Success(B: APValue::LValueBase(
8878 E, 0, Info.getASTContext().getNextStringLiteralVersion()));
8879 }
8880 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(B: E); }
8881 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
8882 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
8883 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
8884 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E);
8885 bool VisitUnaryDeref(const UnaryOperator *E);
8886 bool VisitUnaryReal(const UnaryOperator *E);
8887 bool VisitUnaryImag(const UnaryOperator *E);
8888 bool VisitUnaryPreInc(const UnaryOperator *UO) {
8889 return VisitUnaryPreIncDec(UO);
8890 }
8891 bool VisitUnaryPreDec(const UnaryOperator *UO) {
8892 return VisitUnaryPreIncDec(UO);
8893 }
8894 bool VisitBinAssign(const BinaryOperator *BO);
8895 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
8896
8897 bool VisitCastExpr(const CastExpr *E) {
8898 switch (E->getCastKind()) {
8899 default:
8900 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
8901
8902 case CK_LValueBitCast:
8903 this->CCEDiag(E, D: diag::note_constexpr_invalid_cast)
8904 << diag::ConstexprInvalidCastKind::ThisConversionOrReinterpret
8905 << Info.Ctx.getLangOpts().CPlusPlus;
8906 if (!Visit(S: E->getSubExpr()))
8907 return false;
8908 Result.Designator.setInvalid();
8909 return true;
8910
8911 case CK_BaseToDerived:
8912 if (!Visit(S: E->getSubExpr()))
8913 return false;
8914 return HandleBaseToDerivedCast(Info, E, Result);
8915
8916 case CK_Dynamic:
8917 if (!Visit(S: E->getSubExpr()))
8918 return false;
8919 return HandleDynamicCast(Info, E: cast<ExplicitCastExpr>(Val: E), Ptr&: Result);
8920 }
8921 }
8922};
8923} // end anonymous namespace
8924
8925/// Get an lvalue to a field of a lambda's closure type.
8926static bool HandleLambdaCapture(EvalInfo &Info, const Expr *E, LValue &Result,
8927 const CXXMethodDecl *MD, const FieldDecl *FD,
8928 bool LValueToRValueConversion) {
8929 // Static lambda function call operators can't have captures. We already
8930 // diagnosed this, so bail out here.
8931 if (MD->isStatic()) {
8932 assert(Info.CurrentCall->This == nullptr &&
8933 "This should not be set for a static call operator");
8934 return false;
8935 }
8936
8937 // Start with 'Result' referring to the complete closure object...
8938 if (MD->isExplicitObjectMemberFunction()) {
8939 // Self may be passed by reference or by value.
8940 const ParmVarDecl *Self = MD->getParamDecl(i: 0);
8941 if (Self->getType()->isReferenceType()) {
8942 APValue *RefValue = Info.getParamSlot(Call: Info.CurrentCall->Arguments, PVD: Self);
8943 if (!RefValue->allowConstexprUnknown() || RefValue->hasValue())
8944 Result.setFrom(Ctx&: Info.Ctx, V: *RefValue);
8945 } else {
8946 const ParmVarDecl *VD = Info.CurrentCall->Arguments.getOrigParam(PVD: Self);
8947 CallStackFrame *Frame =
8948 Info.getCallFrameAndDepth(CallIndex: Info.CurrentCall->Arguments.CallIndex)
8949 .first;
8950 unsigned Version = Info.CurrentCall->Arguments.Version;
8951 Result.set(B: {VD, Frame->Index, Version});
8952 }
8953 } else
8954 Result = *Info.CurrentCall->This;
8955
8956 // ... then update it to refer to the field of the closure object
8957 // that represents the capture.
8958 if (!HandleLValueMember(Info, E, LVal&: Result, FD))
8959 return false;
8960
8961 // And if the field is of reference type (or if we captured '*this' by
8962 // reference), update 'Result' to refer to what
8963 // the field refers to.
8964 if (LValueToRValueConversion) {
8965 APValue RVal;
8966 if (!handleLValueToRValueConversion(Info, Conv: E, Type: FD->getType(), LVal: Result, RVal))
8967 return false;
8968 Result.setFrom(Ctx&: Info.Ctx, V: RVal);
8969 }
8970 return true;
8971}
8972
8973/// Evaluate an expression as an lvalue. This can be legitimately called on
8974/// expressions which are not glvalues, in three cases:
8975/// * function designators in C, and
8976/// * "extern void" objects
8977/// * @selector() expressions in Objective-C
8978static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
8979 bool InvalidBaseOK) {
8980 assert(!E->isValueDependent());
8981 assert(E->isGLValue() || E->getType()->isFunctionType() ||
8982 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E->IgnoreParens()));
8983 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(S: E);
8984}
8985
8986bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
8987 const NamedDecl *D = E->getDecl();
8988 if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl,
8989 UnnamedGlobalConstantDecl>(Val: D))
8990 return Success(B: cast<ValueDecl>(Val: D));
8991 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
8992 return VisitVarDecl(E, VD);
8993 if (const BindingDecl *BD = dyn_cast<BindingDecl>(Val: D))
8994 return Visit(S: BD->getBinding());
8995 return Error(E);
8996}
8997
8998bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
8999 // If we are within a lambda's call operator, check whether the 'VD' referred
9000 // to within 'E' actually represents a lambda-capture that maps to a
9001 // data-member/field within the closure object, and if so, evaluate to the
9002 // field or what the field refers to.
9003 if (Info.CurrentCall && isLambdaCallOperator(DC: Info.CurrentCall->Callee) &&
9004 isa<DeclRefExpr>(Val: E) &&
9005 cast<DeclRefExpr>(Val: E)->refersToEnclosingVariableOrCapture()) {
9006 // We don't always have a complete capture-map when checking or inferring if
9007 // the function call operator meets the requirements of a constexpr function
9008 // - but we don't need to evaluate the captures to determine constexprness
9009 // (dcl.constexpr C++17).
9010 if (Info.checkingPotentialConstantExpression())
9011 return false;
9012
9013 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(Val: VD)) {
9014 const auto *MD = cast<CXXMethodDecl>(Val: Info.CurrentCall->Callee);
9015 return HandleLambdaCapture(Info, E, Result, MD, FD,
9016 LValueToRValueConversion: FD->getType()->isReferenceType());
9017 }
9018 }
9019
9020 CallStackFrame *Frame = nullptr;
9021 unsigned Version = 0;
9022 if (VD->hasLocalStorage()) {
9023 // Only if a local variable was declared in the function currently being
9024 // evaluated, do we expect to be able to find its value in the current
9025 // frame. (Otherwise it was likely declared in an enclosing context and
9026 // could either have a valid evaluatable value (for e.g. a constexpr
9027 // variable) or be ill-formed (and trigger an appropriate evaluation
9028 // diagnostic)).
9029 CallStackFrame *CurrFrame = Info.CurrentCall;
9030 if (CurrFrame->Callee && CurrFrame->Callee->Equals(DC: VD->getDeclContext())) {
9031 // Function parameters are stored in some caller's frame. (Usually the
9032 // immediate caller, but for an inherited constructor they may be more
9033 // distant.)
9034 if (auto *PVD = dyn_cast<ParmVarDecl>(Val: VD)) {
9035 if (CurrFrame->Arguments) {
9036 VD = CurrFrame->Arguments.getOrigParam(PVD);
9037 Frame =
9038 Info.getCallFrameAndDepth(CallIndex: CurrFrame->Arguments.CallIndex).first;
9039 Version = CurrFrame->Arguments.Version;
9040 }
9041 } else {
9042 Frame = CurrFrame;
9043 Version = CurrFrame->getCurrentTemporaryVersion(Key: VD);
9044 }
9045 }
9046 }
9047
9048 if (!VD->getType()->isReferenceType()) {
9049 if (Frame) {
9050 Result.set(B: {VD, Frame->Index, Version});
9051 return true;
9052 }
9053 return Success(B: VD);
9054 }
9055
9056 if (!Info.getLangOpts().CPlusPlus11) {
9057 Info.CCEDiag(E, DiagId: diag::note_constexpr_ltor_non_integral, ExtraNotes: 1)
9058 << VD << VD->getType();
9059 Info.Note(Loc: VD->getLocation(), DiagId: diag::note_declared_at);
9060 }
9061
9062 APValue *V;
9063 if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, Result&: V))
9064 return false;
9065
9066 return Success(V: *V, E);
9067}
9068
9069bool LValueExprEvaluator::VisitCallExpr(const CallExpr *E) {
9070 if (!IsConstantEvaluatedBuiltinCall(E))
9071 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9072
9073 switch (E->getBuiltinCallee()) {
9074 default:
9075 return false;
9076 case Builtin::BIas_const:
9077 case Builtin::BIforward:
9078 case Builtin::BIforward_like:
9079 case Builtin::BImove:
9080 case Builtin::BImove_if_noexcept:
9081 if (cast<FunctionDecl>(Val: E->getCalleeDecl())->isConstexpr())
9082 return Visit(S: E->getArg(Arg: 0));
9083 break;
9084 }
9085
9086 return ExprEvaluatorBaseTy::VisitCallExpr(E);
9087}
9088
9089bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
9090 const MaterializeTemporaryExpr *E) {
9091 // Walk through the expression to find the materialized temporary itself.
9092 SmallVector<const Expr *, 2> CommaLHSs;
9093 SmallVector<SubobjectAdjustment, 2> Adjustments;
9094 const Expr *Inner =
9095 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHS&: CommaLHSs, Adjustments);
9096
9097 // If we passed any comma operators, evaluate their LHSs.
9098 for (const Expr *E : CommaLHSs)
9099 if (!EvaluateIgnoredValue(Info, E))
9100 return false;
9101
9102 // A materialized temporary with static storage duration can appear within the
9103 // result of a constant expression evaluation, so we need to preserve its
9104 // value for use outside this evaluation.
9105 APValue *Value;
9106 if (E->getStorageDuration() == SD_Static) {
9107 if (Info.EvalMode == EvalInfo::EM_ConstantFold)
9108 return false;
9109 // FIXME: What about SD_Thread?
9110 Value = E->getOrCreateValue(MayCreate: true);
9111 *Value = APValue();
9112 Result.set(B: E);
9113 } else {
9114 Value = &Info.CurrentCall->createTemporary(
9115 Key: E, T: Inner->getType(),
9116 Scope: E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression
9117 : ScopeKind::Block,
9118 LV&: Result);
9119 }
9120
9121 QualType Type = Inner->getType();
9122
9123 // Materialize the temporary itself.
9124 if (!EvaluateInPlace(Result&: *Value, Info, This: Result, E: Inner)) {
9125 *Value = APValue();
9126 return false;
9127 }
9128
9129 // Adjust our lvalue to refer to the desired subobject.
9130 for (unsigned I = Adjustments.size(); I != 0; /**/) {
9131 --I;
9132 switch (Adjustments[I].Kind) {
9133 case SubobjectAdjustment::DerivedToBaseAdjustment:
9134 if (!HandleLValueBasePath(Info, E: Adjustments[I].DerivedToBase.BasePath,
9135 Type, Result))
9136 return false;
9137 Type = Adjustments[I].DerivedToBase.BasePath->getType();
9138 break;
9139
9140 case SubobjectAdjustment::FieldAdjustment:
9141 if (!HandleLValueMember(Info, E, LVal&: Result, FD: Adjustments[I].Field))
9142 return false;
9143 Type = Adjustments[I].Field->getType();
9144 break;
9145
9146 case SubobjectAdjustment::MemberPointerAdjustment:
9147 if (!HandleMemberPointerAccess(Info&: this->Info, LVType: Type, LV&: Result,
9148 RHS: Adjustments[I].Ptr.RHS))
9149 return false;
9150 Type = Adjustments[I].Ptr.MPT->getPointeeType();
9151 break;
9152 }
9153 }
9154
9155 return true;
9156}
9157
9158bool
9159LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
9160 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
9161 "lvalue compound literal in c++?");
9162 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
9163 // only see this when folding in C, so there's no standard to follow here.
9164 return Success(B: E);
9165}
9166
9167bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
9168 TypeInfoLValue TypeInfo;
9169
9170 if (!E->isPotentiallyEvaluated()) {
9171 if (E->isTypeOperand())
9172 TypeInfo = TypeInfoLValue(E->getTypeOperand(Context: Info.Ctx).getTypePtr());
9173 else
9174 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
9175 } else {
9176 if (!Info.Ctx.getLangOpts().CPlusPlus20) {
9177 Info.CCEDiag(E, DiagId: diag::note_constexpr_typeid_polymorphic)
9178 << E->getExprOperand()->getType()
9179 << E->getExprOperand()->getSourceRange();
9180 }
9181
9182 if (!Visit(S: E->getExprOperand()))
9183 return false;
9184
9185 std::optional<DynamicType> DynType =
9186 ComputeDynamicType(Info, E, This&: Result, AK: AK_TypeId);
9187 if (!DynType)
9188 return false;
9189
9190 TypeInfo =
9191 TypeInfoLValue(Info.Ctx.getRecordType(Decl: DynType->Type).getTypePtr());
9192 }
9193
9194 return Success(B: APValue::LValueBase::getTypeInfo(LV: TypeInfo, TypeInfo: E->getType()));
9195}
9196
9197bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
9198 return Success(B: E->getGuidDecl());
9199}
9200
9201bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
9202 // Handle static data members.
9203 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: E->getMemberDecl())) {
9204 VisitIgnoredBaseExpression(E: E->getBase());
9205 return VisitVarDecl(E, VD);
9206 }
9207
9208 // Handle static member functions.
9209 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: E->getMemberDecl())) {
9210 if (MD->isStatic()) {
9211 VisitIgnoredBaseExpression(E: E->getBase());
9212 return Success(B: MD);
9213 }
9214 }
9215
9216 // Handle non-static data members.
9217 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
9218}
9219
9220bool LValueExprEvaluator::VisitExtVectorElementExpr(
9221 const ExtVectorElementExpr *E) {
9222 bool Success = true;
9223
9224 APValue Val;
9225 if (!Evaluate(Result&: Val, Info, E: E->getBase())) {
9226 if (!Info.noteFailure())
9227 return false;
9228 Success = false;
9229 }
9230
9231 SmallVector<uint32_t, 4> Indices;
9232 E->getEncodedElementAccess(Elts&: Indices);
9233 // FIXME: support accessing more than one element
9234 if (Indices.size() > 1)
9235 return false;
9236
9237 if (Success) {
9238 Result.setFrom(Ctx&: Info.Ctx, V: Val);
9239 QualType BaseType = E->getBase()->getType();
9240 if (E->isArrow())
9241 BaseType = BaseType->getPointeeType();
9242 const auto *VT = BaseType->castAs<VectorType>();
9243 HandleLValueVectorElement(Info, E, LVal&: Result, EltTy: VT->getElementType(),
9244 Size: VT->getNumElements(), Idx: Indices[0]);
9245 }
9246
9247 return Success;
9248}
9249
9250bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
9251 if (E->getBase()->getType()->isSveVLSBuiltinType())
9252 return Error(E);
9253
9254 APSInt Index;
9255 bool Success = true;
9256
9257 if (const auto *VT = E->getBase()->getType()->getAs<VectorType>()) {
9258 APValue Val;
9259 if (!Evaluate(Result&: Val, Info, E: E->getBase())) {
9260 if (!Info.noteFailure())
9261 return false;
9262 Success = false;
9263 }
9264
9265 if (!EvaluateInteger(E: E->getIdx(), Result&: Index, Info)) {
9266 if (!Info.noteFailure())
9267 return false;
9268 Success = false;
9269 }
9270
9271 if (Success) {
9272 Result.setFrom(Ctx&: Info.Ctx, V: Val);
9273 HandleLValueVectorElement(Info, E, LVal&: Result, EltTy: VT->getElementType(),
9274 Size: VT->getNumElements(), Idx: Index.getExtValue());
9275 }
9276
9277 return Success;
9278 }
9279
9280 // C++17's rules require us to evaluate the LHS first, regardless of which
9281 // side is the base.
9282 for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) {
9283 if (SubExpr == E->getBase() ? !evaluatePointer(E: SubExpr, Result)
9284 : !EvaluateInteger(E: SubExpr, Result&: Index, Info)) {
9285 if (!Info.noteFailure())
9286 return false;
9287 Success = false;
9288 }
9289 }
9290
9291 return Success &&
9292 HandleLValueArrayAdjustment(Info, E, LVal&: Result, EltTy: E->getType(), Adjustment: Index);
9293}
9294
9295bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
9296 return evaluatePointer(E: E->getSubExpr(), Result);
9297}
9298
9299bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
9300 if (!Visit(S: E->getSubExpr()))
9301 return false;
9302 // __real is a no-op on scalar lvalues.
9303 if (E->getSubExpr()->getType()->isAnyComplexType())
9304 HandleLValueComplexElement(Info, E, LVal&: Result, EltTy: E->getType(), Imag: false);
9305 return true;
9306}
9307
9308bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
9309 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
9310 "lvalue __imag__ on scalar?");
9311 if (!Visit(S: E->getSubExpr()))
9312 return false;
9313 HandleLValueComplexElement(Info, E, LVal&: Result, EltTy: E->getType(), Imag: true);
9314 return true;
9315}
9316
9317bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
9318 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
9319 return Error(E: UO);
9320
9321 if (!this->Visit(S: UO->getSubExpr()))
9322 return false;
9323
9324 return handleIncDec(
9325 Info&: this->Info, E: UO, LVal: Result, LValType: UO->getSubExpr()->getType(),
9326 IsIncrement: UO->isIncrementOp(), Old: nullptr);
9327}
9328
9329bool LValueExprEvaluator::VisitCompoundAssignOperator(
9330 const CompoundAssignOperator *CAO) {
9331 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
9332 return Error(E: CAO);
9333
9334 bool Success = true;
9335
9336 // C++17 onwards require that we evaluate the RHS first.
9337 APValue RHS;
9338 if (!Evaluate(Result&: RHS, Info&: this->Info, E: CAO->getRHS())) {
9339 if (!Info.noteFailure())
9340 return false;
9341 Success = false;
9342 }
9343
9344 // The overall lvalue result is the result of evaluating the LHS.
9345 if (!this->Visit(S: CAO->getLHS()) || !Success)
9346 return false;
9347
9348 return handleCompoundAssignment(
9349 Info&: this->Info, E: CAO,
9350 LVal: Result, LValType: CAO->getLHS()->getType(), PromotedLValType: CAO->getComputationLHSType(),
9351 Opcode: CAO->getOpForCompoundAssignment(Opc: CAO->getOpcode()), RVal: RHS);
9352}
9353
9354bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
9355 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
9356 return Error(E);
9357
9358 bool Success = true;
9359
9360 // C++17 onwards require that we evaluate the RHS first.
9361 APValue NewVal;
9362 if (!Evaluate(Result&: NewVal, Info&: this->Info, E: E->getRHS())) {
9363 if (!Info.noteFailure())
9364 return false;
9365 Success = false;
9366 }
9367
9368 if (!this->Visit(S: E->getLHS()) || !Success)
9369 return false;
9370
9371 if (Info.getLangOpts().CPlusPlus20 &&
9372 !MaybeHandleUnionActiveMemberChange(Info, LHSExpr: E->getLHS(), LHS: Result))
9373 return false;
9374
9375 return handleAssignment(Info&: this->Info, E, LVal: Result, LValType: E->getLHS()->getType(),
9376 Val&: NewVal);
9377}
9378
9379//===----------------------------------------------------------------------===//
9380// Pointer Evaluation
9381//===----------------------------------------------------------------------===//
9382
9383/// Attempts to compute the number of bytes available at the pointer
9384/// returned by a function with the alloc_size attribute. Returns true if we
9385/// were successful. Places an unsigned number into `Result`.
9386///
9387/// This expects the given CallExpr to be a call to a function with an
9388/// alloc_size attribute.
9389static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
9390 const CallExpr *Call,
9391 llvm::APInt &Result) {
9392 const AllocSizeAttr *AllocSize = getAllocSizeAttr(CE: Call);
9393
9394 assert(AllocSize && AllocSize->getElemSizeParam().isValid());
9395 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
9396 unsigned BitsInSizeT = Ctx.getTypeSize(T: Ctx.getSizeType());
9397 if (Call->getNumArgs() <= SizeArgNo)
9398 return false;
9399
9400 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
9401 Expr::EvalResult ExprResult;
9402 if (!E->EvaluateAsInt(Result&: ExprResult, Ctx, AllowSideEffects: Expr::SE_AllowSideEffects))
9403 return false;
9404 Into = ExprResult.Val.getInt();
9405 if (Into.isNegative() || !Into.isIntN(N: BitsInSizeT))
9406 return false;
9407 Into = Into.zext(width: BitsInSizeT);
9408 return true;
9409 };
9410
9411 APSInt SizeOfElem;
9412 if (!EvaluateAsSizeT(Call->getArg(Arg: SizeArgNo), SizeOfElem))
9413 return false;
9414
9415 if (!AllocSize->getNumElemsParam().isValid()) {
9416 Result = std::move(SizeOfElem);
9417 return true;
9418 }
9419
9420 APSInt NumberOfElems;
9421 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
9422 if (!EvaluateAsSizeT(Call->getArg(Arg: NumArgNo), NumberOfElems))
9423 return false;
9424
9425 bool Overflow;
9426 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(RHS: NumberOfElems, Overflow);
9427 if (Overflow)
9428 return false;
9429
9430 Result = std::move(BytesAvailable);
9431 return true;
9432}
9433
9434/// Convenience function. LVal's base must be a call to an alloc_size
9435/// function.
9436static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
9437 const LValue &LVal,
9438 llvm::APInt &Result) {
9439 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
9440 "Can't get the size of a non alloc_size function");
9441 const auto *Base = LVal.getLValueBase().get<const Expr *>();
9442 const CallExpr *CE = tryUnwrapAllocSizeCall(E: Base);
9443 return getBytesReturnedByAllocSizeCall(Ctx, Call: CE, Result);
9444}
9445
9446/// Attempts to evaluate the given LValueBase as the result of a call to
9447/// a function with the alloc_size attribute. If it was possible to do so, this
9448/// function will return true, make Result's Base point to said function call,
9449/// and mark Result's Base as invalid.
9450static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
9451 LValue &Result) {
9452 if (Base.isNull())
9453 return false;
9454
9455 // Because we do no form of static analysis, we only support const variables.
9456 //
9457 // Additionally, we can't support parameters, nor can we support static
9458 // variables (in the latter case, use-before-assign isn't UB; in the former,
9459 // we have no clue what they'll be assigned to).
9460 const auto *VD =
9461 dyn_cast_or_null<VarDecl>(Val: Base.dyn_cast<const ValueDecl *>());
9462 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
9463 return false;
9464
9465 const Expr *Init = VD->getAnyInitializer();
9466 if (!Init || Init->getType().isNull())
9467 return false;
9468
9469 const Expr *E = Init->IgnoreParens();
9470 if (!tryUnwrapAllocSizeCall(E))
9471 return false;
9472
9473 // Store E instead of E unwrapped so that the type of the LValue's base is
9474 // what the user wanted.
9475 Result.setInvalid(B: E);
9476
9477 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
9478 Result.addUnsizedArray(Info, E, ElemTy: Pointee);
9479 return true;
9480}
9481
9482namespace {
9483class PointerExprEvaluator
9484 : public ExprEvaluatorBase<PointerExprEvaluator> {
9485 LValue &Result;
9486 bool InvalidBaseOK;
9487
9488 bool Success(const Expr *E) {
9489 Result.set(B: E);
9490 return true;
9491 }
9492
9493 bool evaluateLValue(const Expr *E, LValue &Result) {
9494 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
9495 }
9496
9497 bool evaluatePointer(const Expr *E, LValue &Result) {
9498 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
9499 }
9500
9501 bool visitNonBuiltinCallExpr(const CallExpr *E);
9502public:
9503
9504 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
9505 : ExprEvaluatorBaseTy(info), Result(Result),
9506 InvalidBaseOK(InvalidBaseOK) {}
9507
9508 bool Success(const APValue &V, const Expr *E) {
9509 Result.setFrom(Ctx&: Info.Ctx, V);
9510 return true;
9511 }
9512 bool ZeroInitialization(const Expr *E) {
9513 Result.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
9514 return true;
9515 }
9516
9517 bool VisitBinaryOperator(const BinaryOperator *E);
9518 bool VisitCastExpr(const CastExpr* E);
9519 bool VisitUnaryAddrOf(const UnaryOperator *E);
9520 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
9521 { return Success(E); }
9522 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
9523 if (E->isExpressibleAsConstantInitializer())
9524 return Success(E);
9525 if (Info.noteFailure())
9526 EvaluateIgnoredValue(Info, E: E->getSubExpr());
9527 return Error(E);
9528 }
9529 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
9530 { return Success(E); }
9531 bool VisitCallExpr(const CallExpr *E);
9532 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
9533 bool VisitBlockExpr(const BlockExpr *E) {
9534 if (!E->getBlockDecl()->hasCaptures())
9535 return Success(E);
9536 return Error(E);
9537 }
9538 bool VisitCXXThisExpr(const CXXThisExpr *E) {
9539 auto DiagnoseInvalidUseOfThis = [&] {
9540 if (Info.getLangOpts().CPlusPlus11)
9541 Info.FFDiag(E, DiagId: diag::note_constexpr_this) << E->isImplicit();
9542 else
9543 Info.FFDiag(E);
9544 };
9545
9546 // Can't look at 'this' when checking a potential constant expression.
9547 if (Info.checkingPotentialConstantExpression())
9548 return false;
9549
9550 bool IsExplicitLambda =
9551 isLambdaCallWithExplicitObjectParameter(DC: Info.CurrentCall->Callee);
9552 if (!IsExplicitLambda) {
9553 if (!Info.CurrentCall->This) {
9554 DiagnoseInvalidUseOfThis();
9555 return false;
9556 }
9557
9558 Result = *Info.CurrentCall->This;
9559 }
9560
9561 if (isLambdaCallOperator(DC: Info.CurrentCall->Callee)) {
9562 // Ensure we actually have captured 'this'. If something was wrong with
9563 // 'this' capture, the error would have been previously reported.
9564 // Otherwise we can be inside of a default initialization of an object
9565 // declared by lambda's body, so no need to return false.
9566 if (!Info.CurrentCall->LambdaThisCaptureField) {
9567 if (IsExplicitLambda && !Info.CurrentCall->This) {
9568 DiagnoseInvalidUseOfThis();
9569 return false;
9570 }
9571
9572 return true;
9573 }
9574
9575 const auto *MD = cast<CXXMethodDecl>(Val: Info.CurrentCall->Callee);
9576 return HandleLambdaCapture(
9577 Info, E, Result, MD, FD: Info.CurrentCall->LambdaThisCaptureField,
9578 LValueToRValueConversion: Info.CurrentCall->LambdaThisCaptureField->getType()->isPointerType());
9579 }
9580 return true;
9581 }
9582
9583 bool VisitCXXNewExpr(const CXXNewExpr *E);
9584
9585 bool VisitSourceLocExpr(const SourceLocExpr *E) {
9586 assert(!E->isIntType() && "SourceLocExpr isn't a pointer type?");
9587 APValue LValResult = E->EvaluateInContext(
9588 Ctx: Info.Ctx, DefaultExpr: Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
9589 Result.setFrom(Ctx&: Info.Ctx, V: LValResult);
9590 return true;
9591 }
9592
9593 bool VisitEmbedExpr(const EmbedExpr *E) {
9594 llvm::report_fatal_error(reason: "Not yet implemented for ExprConstant.cpp");
9595 return true;
9596 }
9597
9598 bool VisitSYCLUniqueStableNameExpr(const SYCLUniqueStableNameExpr *E) {
9599 std::string ResultStr = E->ComputeName(Context&: Info.Ctx);
9600
9601 QualType CharTy = Info.Ctx.CharTy.withConst();
9602 APInt Size(Info.Ctx.getTypeSize(T: Info.Ctx.getSizeType()),
9603 ResultStr.size() + 1);
9604 QualType ArrayTy = Info.Ctx.getConstantArrayType(
9605 EltTy: CharTy, ArySize: Size, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
9606
9607 StringLiteral *SL =
9608 StringLiteral::Create(Ctx: Info.Ctx, Str: ResultStr, Kind: StringLiteralKind::Ordinary,
9609 /*Pascal*/ false, Ty: ArrayTy, Locs: E->getLocation());
9610
9611 evaluateLValue(E: SL, Result);
9612 Result.addArray(Info, E, CAT: cast<ConstantArrayType>(Val&: ArrayTy));
9613 return true;
9614 }
9615
9616 // FIXME: Missing: @protocol, @selector
9617};
9618} // end anonymous namespace
9619
9620static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
9621 bool InvalidBaseOK) {
9622 assert(!E->isValueDependent());
9623 assert(E->isPRValue() && E->getType()->hasPointerRepresentation());
9624 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(S: E);
9625}
9626
9627bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9628 if (E->getOpcode() != BO_Add &&
9629 E->getOpcode() != BO_Sub)
9630 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9631
9632 const Expr *PExp = E->getLHS();
9633 const Expr *IExp = E->getRHS();
9634 if (IExp->getType()->isPointerType())
9635 std::swap(a&: PExp, b&: IExp);
9636
9637 bool EvalPtrOK = evaluatePointer(E: PExp, Result);
9638 if (!EvalPtrOK && !Info.noteFailure())
9639 return false;
9640
9641 llvm::APSInt Offset;
9642 if (!EvaluateInteger(E: IExp, Result&: Offset, Info) || !EvalPtrOK)
9643 return false;
9644
9645 if (E->getOpcode() == BO_Sub)
9646 negateAsSigned(Int&: Offset);
9647
9648 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
9649 return HandleLValueArrayAdjustment(Info, E, LVal&: Result, EltTy: Pointee, Adjustment: Offset);
9650}
9651
9652bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
9653 return evaluateLValue(E: E->getSubExpr(), Result);
9654}
9655
9656// Is the provided decl 'std::source_location::current'?
9657static bool IsDeclSourceLocationCurrent(const FunctionDecl *FD) {
9658 if (!FD)
9659 return false;
9660 const IdentifierInfo *FnII = FD->getIdentifier();
9661 if (!FnII || !FnII->isStr(Str: "current"))
9662 return false;
9663
9664 const auto *RD = dyn_cast<RecordDecl>(Val: FD->getParent());
9665 if (!RD)
9666 return false;
9667
9668 const IdentifierInfo *ClassII = RD->getIdentifier();
9669 return RD->isInStdNamespace() && ClassII && ClassII->isStr(Str: "source_location");
9670}
9671
9672bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
9673 const Expr *SubExpr = E->getSubExpr();
9674
9675 switch (E->getCastKind()) {
9676 default:
9677 break;
9678 case CK_BitCast:
9679 case CK_CPointerToObjCPointerCast:
9680 case CK_BlockPointerToObjCPointerCast:
9681 case CK_AnyPointerToBlockPointerCast:
9682 case CK_AddressSpaceConversion:
9683 if (!Visit(S: SubExpr))
9684 return false;
9685 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
9686 // permitted in constant expressions in C++11. Bitcasts from cv void* are
9687 // also static_casts, but we disallow them as a resolution to DR1312.
9688 if (!E->getType()->isVoidPointerType()) {
9689 // In some circumstances, we permit casting from void* to cv1 T*, when the
9690 // actual pointee object is actually a cv2 T.
9691 bool HasValidResult = !Result.InvalidBase && !Result.Designator.Invalid &&
9692 !Result.IsNullPtr;
9693 bool VoidPtrCastMaybeOK =
9694 Result.IsNullPtr ||
9695 (HasValidResult &&
9696 Info.Ctx.hasSimilarType(T1: Result.Designator.getType(Ctx&: Info.Ctx),
9697 T2: E->getType()->getPointeeType()));
9698 // 1. We'll allow it in std::allocator::allocate, and anything which that
9699 // calls.
9700 // 2. HACK 2022-03-28: Work around an issue with libstdc++'s
9701 // <source_location> header. Fixed in GCC 12 and later (2022-04-??).
9702 // We'll allow it in the body of std::source_location::current. GCC's
9703 // implementation had a parameter of type `void*`, and casts from
9704 // that back to `const __impl*` in its body.
9705 if (VoidPtrCastMaybeOK &&
9706 (Info.getStdAllocatorCaller(FnName: "allocate") ||
9707 IsDeclSourceLocationCurrent(FD: Info.CurrentCall->Callee) ||
9708 Info.getLangOpts().CPlusPlus26)) {
9709 // Permitted.
9710 } else {
9711 if (SubExpr->getType()->isVoidPointerType() &&
9712 Info.getLangOpts().CPlusPlus) {
9713 if (HasValidResult)
9714 CCEDiag(E, D: diag::note_constexpr_invalid_void_star_cast)
9715 << SubExpr->getType() << Info.getLangOpts().CPlusPlus26
9716 << Result.Designator.getType(Ctx&: Info.Ctx).getCanonicalType()
9717 << E->getType()->getPointeeType();
9718 else
9719 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
9720 << diag::ConstexprInvalidCastKind::CastFrom
9721 << SubExpr->getType();
9722 } else
9723 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
9724 << diag::ConstexprInvalidCastKind::ThisConversionOrReinterpret
9725 << Info.Ctx.getLangOpts().CPlusPlus;
9726 Result.Designator.setInvalid();
9727 }
9728 }
9729 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
9730 ZeroInitialization(E);
9731 return true;
9732
9733 case CK_DerivedToBase:
9734 case CK_UncheckedDerivedToBase:
9735 if (!evaluatePointer(E: E->getSubExpr(), Result))
9736 return false;
9737 if (!Result.Base && Result.Offset.isZero())
9738 return true;
9739
9740 // Now figure out the necessary offset to add to the base LV to get from
9741 // the derived class to the base class.
9742 return HandleLValueBasePath(Info, E, Type: E->getSubExpr()->getType()->
9743 castAs<PointerType>()->getPointeeType(),
9744 Result);
9745
9746 case CK_BaseToDerived:
9747 if (!Visit(S: E->getSubExpr()))
9748 return false;
9749 if (!Result.Base && Result.Offset.isZero())
9750 return true;
9751 return HandleBaseToDerivedCast(Info, E, Result);
9752
9753 case CK_Dynamic:
9754 if (!Visit(S: E->getSubExpr()))
9755 return false;
9756 return HandleDynamicCast(Info, E: cast<ExplicitCastExpr>(Val: E), Ptr&: Result);
9757
9758 case CK_NullToPointer:
9759 VisitIgnoredValue(E: E->getSubExpr());
9760 return ZeroInitialization(E);
9761
9762 case CK_IntegralToPointer: {
9763 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
9764 << diag::ConstexprInvalidCastKind::ThisConversionOrReinterpret
9765 << Info.Ctx.getLangOpts().CPlusPlus;
9766
9767 APValue Value;
9768 if (!EvaluateIntegerOrLValue(E: SubExpr, Result&: Value, Info))
9769 break;
9770
9771 if (Value.isInt()) {
9772 unsigned Size = Info.Ctx.getTypeSize(T: E->getType());
9773 uint64_t N = Value.getInt().extOrTrunc(width: Size).getZExtValue();
9774 Result.Base = (Expr*)nullptr;
9775 Result.InvalidBase = false;
9776 Result.Offset = CharUnits::fromQuantity(Quantity: N);
9777 Result.Designator.setInvalid();
9778 Result.IsNullPtr = false;
9779 return true;
9780 } else {
9781 // In rare instances, the value isn't an lvalue.
9782 // For example, when the value is the difference between the addresses of
9783 // two labels. We reject that as a constant expression because we can't
9784 // compute a valid offset to convert into a pointer.
9785 if (!Value.isLValue())
9786 return false;
9787
9788 // Cast is of an lvalue, no need to change value.
9789 Result.setFrom(Ctx&: Info.Ctx, V: Value);
9790 return true;
9791 }
9792 }
9793
9794 case CK_ArrayToPointerDecay: {
9795 if (SubExpr->isGLValue()) {
9796 if (!evaluateLValue(E: SubExpr, Result))
9797 return false;
9798 } else {
9799 APValue &Value = Info.CurrentCall->createTemporary(
9800 Key: SubExpr, T: SubExpr->getType(), Scope: ScopeKind::FullExpression, LV&: Result);
9801 if (!EvaluateInPlace(Result&: Value, Info, This: Result, E: SubExpr))
9802 return false;
9803 }
9804 // The result is a pointer to the first element of the array.
9805 auto *AT = Info.Ctx.getAsArrayType(T: SubExpr->getType());
9806 if (auto *CAT = dyn_cast<ConstantArrayType>(Val: AT))
9807 Result.addArray(Info, E, CAT);
9808 else
9809 Result.addUnsizedArray(Info, E, ElemTy: AT->getElementType());
9810 return true;
9811 }
9812
9813 case CK_FunctionToPointerDecay:
9814 return evaluateLValue(E: SubExpr, Result);
9815
9816 case CK_LValueToRValue: {
9817 LValue LVal;
9818 if (!evaluateLValue(E: E->getSubExpr(), Result&: LVal))
9819 return false;
9820
9821 APValue RVal;
9822 // Note, we use the subexpression's type in order to retain cv-qualifiers.
9823 if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getSubExpr()->getType(),
9824 LVal, RVal))
9825 return InvalidBaseOK &&
9826 evaluateLValueAsAllocSize(Info, Base: LVal.Base, Result);
9827 return Success(V: RVal, E);
9828 }
9829 }
9830
9831 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9832}
9833
9834static CharUnits GetAlignOfType(const ASTContext &Ctx, QualType T,
9835 UnaryExprOrTypeTrait ExprKind) {
9836 // C++ [expr.alignof]p3:
9837 // When alignof is applied to a reference type, the result is the
9838 // alignment of the referenced type.
9839 T = T.getNonReferenceType();
9840
9841 if (T.getQualifiers().hasUnaligned())
9842 return CharUnits::One();
9843
9844 const bool AlignOfReturnsPreferred =
9845 Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;
9846
9847 // __alignof is defined to return the preferred alignment.
9848 // Before 8, clang returned the preferred alignment for alignof and _Alignof
9849 // as well.
9850 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
9851 return Ctx.toCharUnitsFromBits(BitSize: Ctx.getPreferredTypeAlign(T: T.getTypePtr()));
9852 // alignof and _Alignof are defined to return the ABI alignment.
9853 else if (ExprKind == UETT_AlignOf)
9854 return Ctx.getTypeAlignInChars(T: T.getTypePtr());
9855 else
9856 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind");
9857}
9858
9859CharUnits GetAlignOfExpr(const ASTContext &Ctx, const Expr *E,
9860 UnaryExprOrTypeTrait ExprKind) {
9861 E = E->IgnoreParens();
9862
9863 // The kinds of expressions that we have special-case logic here for
9864 // should be kept up to date with the special checks for those
9865 // expressions in Sema.
9866
9867 // alignof decl is always accepted, even if it doesn't make sense: we default
9868 // to 1 in those cases.
9869 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: E))
9870 return Ctx.getDeclAlign(D: DRE->getDecl(),
9871 /*RefAsPointee*/ ForAlignof: true);
9872
9873 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Val: E))
9874 return Ctx.getDeclAlign(D: ME->getMemberDecl(),
9875 /*RefAsPointee*/ ForAlignof: true);
9876
9877 return GetAlignOfType(Ctx, T: E->getType(), ExprKind);
9878}
9879
9880static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
9881 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
9882 return Info.Ctx.getDeclAlign(D: VD);
9883 if (const auto *E = Value.Base.dyn_cast<const Expr *>())
9884 return GetAlignOfExpr(Ctx: Info.Ctx, E, ExprKind: UETT_AlignOf);
9885 return GetAlignOfType(Ctx: Info.Ctx, T: Value.Base.getTypeInfoType(), ExprKind: UETT_AlignOf);
9886}
9887
9888/// Evaluate the value of the alignment argument to __builtin_align_{up,down},
9889/// __builtin_is_aligned and __builtin_assume_aligned.
9890static bool getAlignmentArgument(const Expr *E, QualType ForType,
9891 EvalInfo &Info, APSInt &Alignment) {
9892 if (!EvaluateInteger(E, Result&: Alignment, Info))
9893 return false;
9894 if (Alignment < 0 || !Alignment.isPowerOf2()) {
9895 Info.FFDiag(E, DiagId: diag::note_constexpr_invalid_alignment) << Alignment;
9896 return false;
9897 }
9898 unsigned SrcWidth = Info.Ctx.getIntWidth(T: ForType);
9899 APSInt MaxValue(APInt::getOneBitSet(numBits: SrcWidth, BitNo: SrcWidth - 1));
9900 if (APSInt::compareValues(I1: Alignment, I2: MaxValue) > 0) {
9901 Info.FFDiag(E, DiagId: diag::note_constexpr_alignment_too_big)
9902 << MaxValue << ForType << Alignment;
9903 return false;
9904 }
9905 // Ensure both alignment and source value have the same bit width so that we
9906 // don't assert when computing the resulting value.
9907 APSInt ExtAlignment =
9908 APSInt(Alignment.zextOrTrunc(width: SrcWidth), /*isUnsigned=*/true);
9909 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&
9910 "Alignment should not be changed by ext/trunc");
9911 Alignment = ExtAlignment;
9912 assert(Alignment.getBitWidth() == SrcWidth);
9913 return true;
9914}
9915
9916// To be clear: this happily visits unsupported builtins. Better name welcomed.
9917bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
9918 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
9919 return true;
9920
9921 if (!(InvalidBaseOK && getAllocSizeAttr(CE: E)))
9922 return false;
9923
9924 Result.setInvalid(B: E);
9925 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
9926 Result.addUnsizedArray(Info, E, ElemTy: PointeeTy);
9927 return true;
9928}
9929
9930bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
9931 if (!IsConstantEvaluatedBuiltinCall(E))
9932 return visitNonBuiltinCallExpr(E);
9933 return VisitBuiltinCallExpr(E, BuiltinOp: E->getBuiltinCallee());
9934}
9935
9936// Determine if T is a character type for which we guarantee that
9937// sizeof(T) == 1.
9938static bool isOneByteCharacterType(QualType T) {
9939 return T->isCharType() || T->isChar8Type();
9940}
9941
9942bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
9943 unsigned BuiltinOp) {
9944 if (IsOpaqueConstantCall(E))
9945 return Success(E);
9946
9947 switch (BuiltinOp) {
9948 case Builtin::BIaddressof:
9949 case Builtin::BI__addressof:
9950 case Builtin::BI__builtin_addressof:
9951 return evaluateLValue(E: E->getArg(Arg: 0), Result);
9952 case Builtin::BI__builtin_assume_aligned: {
9953 // We need to be very careful here because: if the pointer does not have the
9954 // asserted alignment, then the behavior is undefined, and undefined
9955 // behavior is non-constant.
9956 if (!evaluatePointer(E: E->getArg(Arg: 0), Result))
9957 return false;
9958
9959 LValue OffsetResult(Result);
9960 APSInt Alignment;
9961 if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: E->getArg(Arg: 0)->getType(), Info,
9962 Alignment))
9963 return false;
9964 CharUnits Align = CharUnits::fromQuantity(Quantity: Alignment.getZExtValue());
9965
9966 if (E->getNumArgs() > 2) {
9967 APSInt Offset;
9968 if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: Offset, Info))
9969 return false;
9970
9971 int64_t AdditionalOffset = -Offset.getZExtValue();
9972 OffsetResult.Offset += CharUnits::fromQuantity(Quantity: AdditionalOffset);
9973 }
9974
9975 // If there is a base object, then it must have the correct alignment.
9976 if (OffsetResult.Base) {
9977 CharUnits BaseAlignment = getBaseAlignment(Info, Value: OffsetResult);
9978
9979 if (BaseAlignment < Align) {
9980 Result.Designator.setInvalid();
9981 CCEDiag(E: E->getArg(Arg: 0), D: diag::note_constexpr_baa_insufficient_alignment)
9982 << 0 << BaseAlignment.getQuantity() << Align.getQuantity();
9983 return false;
9984 }
9985 }
9986
9987 // The offset must also have the correct alignment.
9988 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
9989 Result.Designator.setInvalid();
9990
9991 (OffsetResult.Base
9992 ? CCEDiag(E: E->getArg(Arg: 0),
9993 D: diag::note_constexpr_baa_insufficient_alignment)
9994 << 1
9995 : CCEDiag(E: E->getArg(Arg: 0),
9996 D: diag::note_constexpr_baa_value_insufficient_alignment))
9997 << OffsetResult.Offset.getQuantity() << Align.getQuantity();
9998 return false;
9999 }
10000
10001 return true;
10002 }
10003 case Builtin::BI__builtin_align_up:
10004 case Builtin::BI__builtin_align_down: {
10005 if (!evaluatePointer(E: E->getArg(Arg: 0), Result))
10006 return false;
10007 APSInt Alignment;
10008 if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: E->getArg(Arg: 0)->getType(), Info,
10009 Alignment))
10010 return false;
10011 CharUnits BaseAlignment = getBaseAlignment(Info, Value: Result);
10012 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(offset: Result.Offset);
10013 // For align_up/align_down, we can return the same value if the alignment
10014 // is known to be greater or equal to the requested value.
10015 if (PtrAlign.getQuantity() >= Alignment)
10016 return true;
10017
10018 // The alignment could be greater than the minimum at run-time, so we cannot
10019 // infer much about the resulting pointer value. One case is possible:
10020 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
10021 // can infer the correct index if the requested alignment is smaller than
10022 // the base alignment so we can perform the computation on the offset.
10023 if (BaseAlignment.getQuantity() >= Alignment) {
10024 assert(Alignment.getBitWidth() <= 64 &&
10025 "Cannot handle > 64-bit address-space");
10026 uint64_t Alignment64 = Alignment.getZExtValue();
10027 CharUnits NewOffset = CharUnits::fromQuantity(
10028 Quantity: BuiltinOp == Builtin::BI__builtin_align_down
10029 ? llvm::alignDown(Value: Result.Offset.getQuantity(), Align: Alignment64)
10030 : llvm::alignTo(Value: Result.Offset.getQuantity(), Align: Alignment64));
10031 Result.adjustOffset(N: NewOffset - Result.Offset);
10032 // TODO: diagnose out-of-bounds values/only allow for arrays?
10033 return true;
10034 }
10035 // Otherwise, we cannot constant-evaluate the result.
10036 Info.FFDiag(E: E->getArg(Arg: 0), DiagId: diag::note_constexpr_alignment_adjust)
10037 << Alignment;
10038 return false;
10039 }
10040 case Builtin::BI__builtin_operator_new:
10041 return HandleOperatorNewCall(Info, E, Result);
10042 case Builtin::BI__builtin_launder:
10043 return evaluatePointer(E: E->getArg(Arg: 0), Result);
10044 case Builtin::BIstrchr:
10045 case Builtin::BIwcschr:
10046 case Builtin::BImemchr:
10047 case Builtin::BIwmemchr:
10048 if (Info.getLangOpts().CPlusPlus11)
10049 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_function)
10050 << /*isConstexpr*/ 0 << /*isConstructor*/ 0
10051 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp);
10052 else
10053 Info.CCEDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
10054 [[fallthrough]];
10055 case Builtin::BI__builtin_strchr:
10056 case Builtin::BI__builtin_wcschr:
10057 case Builtin::BI__builtin_memchr:
10058 case Builtin::BI__builtin_char_memchr:
10059 case Builtin::BI__builtin_wmemchr: {
10060 if (!Visit(S: E->getArg(Arg: 0)))
10061 return false;
10062 APSInt Desired;
10063 if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: Desired, Info))
10064 return false;
10065 uint64_t MaxLength = uint64_t(-1);
10066 if (BuiltinOp != Builtin::BIstrchr &&
10067 BuiltinOp != Builtin::BIwcschr &&
10068 BuiltinOp != Builtin::BI__builtin_strchr &&
10069 BuiltinOp != Builtin::BI__builtin_wcschr) {
10070 APSInt N;
10071 if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
10072 return false;
10073 MaxLength = N.getZExtValue();
10074 }
10075 // We cannot find the value if there are no candidates to match against.
10076 if (MaxLength == 0u)
10077 return ZeroInitialization(E);
10078 if (!Result.checkNullPointerForFoldAccess(Info, E, AK: AK_Read) ||
10079 Result.Designator.Invalid)
10080 return false;
10081 QualType CharTy = Result.Designator.getType(Ctx&: Info.Ctx);
10082 bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
10083 BuiltinOp == Builtin::BI__builtin_memchr;
10084 assert(IsRawByte ||
10085 Info.Ctx.hasSameUnqualifiedType(
10086 CharTy, E->getArg(0)->getType()->getPointeeType()));
10087 // Pointers to const void may point to objects of incomplete type.
10088 if (IsRawByte && CharTy->isIncompleteType()) {
10089 Info.FFDiag(E, DiagId: diag::note_constexpr_ltor_incomplete_type) << CharTy;
10090 return false;
10091 }
10092 // Give up on byte-oriented matching against multibyte elements.
10093 // FIXME: We can compare the bytes in the correct order.
10094 if (IsRawByte && !isOneByteCharacterType(T: CharTy)) {
10095 Info.FFDiag(E, DiagId: diag::note_constexpr_memchr_unsupported)
10096 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp) << CharTy;
10097 return false;
10098 }
10099 // Figure out what value we're actually looking for (after converting to
10100 // the corresponding unsigned type if necessary).
10101 uint64_t DesiredVal;
10102 bool StopAtNull = false;
10103 switch (BuiltinOp) {
10104 case Builtin::BIstrchr:
10105 case Builtin::BI__builtin_strchr:
10106 // strchr compares directly to the passed integer, and therefore
10107 // always fails if given an int that is not a char.
10108 if (!APSInt::isSameValue(I1: HandleIntToIntCast(Info, E, DestType: CharTy,
10109 SrcType: E->getArg(Arg: 1)->getType(),
10110 Value: Desired),
10111 I2: Desired))
10112 return ZeroInitialization(E);
10113 StopAtNull = true;
10114 [[fallthrough]];
10115 case Builtin::BImemchr:
10116 case Builtin::BI__builtin_memchr:
10117 case Builtin::BI__builtin_char_memchr:
10118 // memchr compares by converting both sides to unsigned char. That's also
10119 // correct for strchr if we get this far (to cope with plain char being
10120 // unsigned in the strchr case).
10121 DesiredVal = Desired.trunc(width: Info.Ctx.getCharWidth()).getZExtValue();
10122 break;
10123
10124 case Builtin::BIwcschr:
10125 case Builtin::BI__builtin_wcschr:
10126 StopAtNull = true;
10127 [[fallthrough]];
10128 case Builtin::BIwmemchr:
10129 case Builtin::BI__builtin_wmemchr:
10130 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
10131 DesiredVal = Desired.getZExtValue();
10132 break;
10133 }
10134
10135 for (; MaxLength; --MaxLength) {
10136 APValue Char;
10137 if (!handleLValueToRValueConversion(Info, Conv: E, Type: CharTy, LVal: Result, RVal&: Char) ||
10138 !Char.isInt())
10139 return false;
10140 if (Char.getInt().getZExtValue() == DesiredVal)
10141 return true;
10142 if (StopAtNull && !Char.getInt())
10143 break;
10144 if (!HandleLValueArrayAdjustment(Info, E, LVal&: Result, EltTy: CharTy, Adjustment: 1))
10145 return false;
10146 }
10147 // Not found: return nullptr.
10148 return ZeroInitialization(E);
10149 }
10150
10151 case Builtin::BImemcpy:
10152 case Builtin::BImemmove:
10153 case Builtin::BIwmemcpy:
10154 case Builtin::BIwmemmove:
10155 if (Info.getLangOpts().CPlusPlus11)
10156 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_function)
10157 << /*isConstexpr*/ 0 << /*isConstructor*/ 0
10158 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp);
10159 else
10160 Info.CCEDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
10161 [[fallthrough]];
10162 case Builtin::BI__builtin_memcpy:
10163 case Builtin::BI__builtin_memmove:
10164 case Builtin::BI__builtin_wmemcpy:
10165 case Builtin::BI__builtin_wmemmove: {
10166 bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
10167 BuiltinOp == Builtin::BIwmemmove ||
10168 BuiltinOp == Builtin::BI__builtin_wmemcpy ||
10169 BuiltinOp == Builtin::BI__builtin_wmemmove;
10170 bool Move = BuiltinOp == Builtin::BImemmove ||
10171 BuiltinOp == Builtin::BIwmemmove ||
10172 BuiltinOp == Builtin::BI__builtin_memmove ||
10173 BuiltinOp == Builtin::BI__builtin_wmemmove;
10174
10175 // The result of mem* is the first argument.
10176 if (!Visit(S: E->getArg(Arg: 0)))
10177 return false;
10178 LValue Dest = Result;
10179
10180 LValue Src;
10181 if (!EvaluatePointer(E: E->getArg(Arg: 1), Result&: Src, Info))
10182 return false;
10183
10184 APSInt N;
10185 if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
10186 return false;
10187 assert(!N.isSigned() && "memcpy and friends take an unsigned size");
10188
10189 // If the size is zero, we treat this as always being a valid no-op.
10190 // (Even if one of the src and dest pointers is null.)
10191 if (!N)
10192 return true;
10193
10194 // Otherwise, if either of the operands is null, we can't proceed. Don't
10195 // try to determine the type of the copied objects, because there aren't
10196 // any.
10197 if (!Src.Base || !Dest.Base) {
10198 APValue Val;
10199 (!Src.Base ? Src : Dest).moveInto(V&: Val);
10200 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_null)
10201 << Move << WChar << !!Src.Base
10202 << Val.getAsString(Ctx: Info.Ctx, Ty: E->getArg(Arg: 0)->getType());
10203 return false;
10204 }
10205 if (Src.Designator.Invalid || Dest.Designator.Invalid)
10206 return false;
10207
10208 // We require that Src and Dest are both pointers to arrays of
10209 // trivially-copyable type. (For the wide version, the designator will be
10210 // invalid if the designated object is not a wchar_t.)
10211 QualType T = Dest.Designator.getType(Ctx&: Info.Ctx);
10212 QualType SrcT = Src.Designator.getType(Ctx&: Info.Ctx);
10213 if (!Info.Ctx.hasSameUnqualifiedType(T1: T, T2: SrcT)) {
10214 // FIXME: Consider using our bit_cast implementation to support this.
10215 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
10216 return false;
10217 }
10218 if (T->isIncompleteType()) {
10219 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_incomplete_type) << Move << T;
10220 return false;
10221 }
10222 if (!T.isTriviallyCopyableType(Context: Info.Ctx)) {
10223 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_nontrivial) << Move << T;
10224 return false;
10225 }
10226
10227 // Figure out how many T's we're copying.
10228 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
10229 if (TSize == 0)
10230 return false;
10231 if (!WChar) {
10232 uint64_t Remainder;
10233 llvm::APInt OrigN = N;
10234 llvm::APInt::udivrem(LHS: OrigN, RHS: TSize, Quotient&: N, Remainder);
10235 if (Remainder) {
10236 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_unsupported)
10237 << Move << WChar << 0 << T << toString(I: OrigN, Radix: 10, /*Signed*/false)
10238 << (unsigned)TSize;
10239 return false;
10240 }
10241 }
10242
10243 // Check that the copying will remain within the arrays, just so that we
10244 // can give a more meaningful diagnostic. This implicitly also checks that
10245 // N fits into 64 bits.
10246 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
10247 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
10248 if (N.ugt(RHS: RemainingSrcSize) || N.ugt(RHS: RemainingDestSize)) {
10249 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_unsupported)
10250 << Move << WChar << (N.ugt(RHS: RemainingSrcSize) ? 1 : 2) << T
10251 << toString(I: N, Radix: 10, /*Signed*/false);
10252 return false;
10253 }
10254 uint64_t NElems = N.getZExtValue();
10255 uint64_t NBytes = NElems * TSize;
10256
10257 // Check for overlap.
10258 int Direction = 1;
10259 if (HasSameBase(A: Src, B: Dest)) {
10260 uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
10261 uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
10262 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
10263 // Dest is inside the source region.
10264 if (!Move) {
10265 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_overlap) << WChar;
10266 return false;
10267 }
10268 // For memmove and friends, copy backwards.
10269 if (!HandleLValueArrayAdjustment(Info, E, LVal&: Src, EltTy: T, Adjustment: NElems - 1) ||
10270 !HandleLValueArrayAdjustment(Info, E, LVal&: Dest, EltTy: T, Adjustment: NElems - 1))
10271 return false;
10272 Direction = -1;
10273 } else if (!Move && SrcOffset >= DestOffset &&
10274 SrcOffset - DestOffset < NBytes) {
10275 // Src is inside the destination region for memcpy: invalid.
10276 Info.FFDiag(E, DiagId: diag::note_constexpr_memcpy_overlap) << WChar;
10277 return false;
10278 }
10279 }
10280
10281 while (true) {
10282 APValue Val;
10283 // FIXME: Set WantObjectRepresentation to true if we're copying a
10284 // char-like type?
10285 if (!handleLValueToRValueConversion(Info, Conv: E, Type: T, LVal: Src, RVal&: Val) ||
10286 !handleAssignment(Info, E, LVal: Dest, LValType: T, Val))
10287 return false;
10288 // Do not iterate past the last element; if we're copying backwards, that
10289 // might take us off the start of the array.
10290 if (--NElems == 0)
10291 return true;
10292 if (!HandleLValueArrayAdjustment(Info, E, LVal&: Src, EltTy: T, Adjustment: Direction) ||
10293 !HandleLValueArrayAdjustment(Info, E, LVal&: Dest, EltTy: T, Adjustment: Direction))
10294 return false;
10295 }
10296 }
10297
10298 default:
10299 return false;
10300 }
10301}
10302
10303static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
10304 APValue &Result, const InitListExpr *ILE,
10305 QualType AllocType);
10306static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
10307 APValue &Result,
10308 const CXXConstructExpr *CCE,
10309 QualType AllocType);
10310
10311bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
10312 if (!Info.getLangOpts().CPlusPlus20)
10313 Info.CCEDiag(E, DiagId: diag::note_constexpr_new);
10314
10315 // We cannot speculatively evaluate a delete expression.
10316 if (Info.SpeculativeEvaluationDepth)
10317 return false;
10318
10319 FunctionDecl *OperatorNew = E->getOperatorNew();
10320 QualType AllocType = E->getAllocatedType();
10321 QualType TargetType = AllocType;
10322
10323 bool IsNothrow = false;
10324 bool IsPlacement = false;
10325
10326 if (E->getNumPlacementArgs() == 1 &&
10327 E->getPlacementArg(I: 0)->getType()->isNothrowT()) {
10328 // The only new-placement list we support is of the form (std::nothrow).
10329 //
10330 // FIXME: There is no restriction on this, but it's not clear that any
10331 // other form makes any sense. We get here for cases such as:
10332 //
10333 // new (std::align_val_t{N}) X(int)
10334 //
10335 // (which should presumably be valid only if N is a multiple of
10336 // alignof(int), and in any case can't be deallocated unless N is
10337 // alignof(X) and X has new-extended alignment).
10338 LValue Nothrow;
10339 if (!EvaluateLValue(E: E->getPlacementArg(I: 0), Result&: Nothrow, Info))
10340 return false;
10341 IsNothrow = true;
10342 } else if (OperatorNew->isReservedGlobalPlacementOperator()) {
10343 if (Info.CurrentCall->isStdFunction() || Info.getLangOpts().CPlusPlus26 ||
10344 (Info.CurrentCall->CanEvalMSConstexpr &&
10345 OperatorNew->hasAttr<MSConstexprAttr>())) {
10346 if (!EvaluatePointer(E: E->getPlacementArg(I: 0), Result, Info))
10347 return false;
10348 if (Result.Designator.Invalid)
10349 return false;
10350 TargetType = E->getPlacementArg(I: 0)->getType();
10351 IsPlacement = true;
10352 } else {
10353 Info.FFDiag(E, DiagId: diag::note_constexpr_new_placement)
10354 << /*C++26 feature*/ 1 << E->getSourceRange();
10355 return false;
10356 }
10357 } else if (E->getNumPlacementArgs()) {
10358 Info.FFDiag(E, DiagId: diag::note_constexpr_new_placement)
10359 << /*Unsupported*/ 0 << E->getSourceRange();
10360 return false;
10361 } else if (!OperatorNew
10362 ->isUsableAsGlobalAllocationFunctionInConstantEvaluation()) {
10363 Info.FFDiag(E, DiagId: diag::note_constexpr_new_non_replaceable)
10364 << isa<CXXMethodDecl>(Val: OperatorNew) << OperatorNew;
10365 return false;
10366 }
10367
10368 const Expr *Init = E->getInitializer();
10369 const InitListExpr *ResizedArrayILE = nullptr;
10370 const CXXConstructExpr *ResizedArrayCCE = nullptr;
10371 bool ValueInit = false;
10372
10373 if (std::optional<const Expr *> ArraySize = E->getArraySize()) {
10374 const Expr *Stripped = *ArraySize;
10375 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Val: Stripped);
10376 Stripped = ICE->getSubExpr())
10377 if (ICE->getCastKind() != CK_NoOp &&
10378 ICE->getCastKind() != CK_IntegralCast)
10379 break;
10380
10381 llvm::APSInt ArrayBound;
10382 if (!EvaluateInteger(E: Stripped, Result&: ArrayBound, Info))
10383 return false;
10384
10385 // C++ [expr.new]p9:
10386 // The expression is erroneous if:
10387 // -- [...] its value before converting to size_t [or] applying the
10388 // second standard conversion sequence is less than zero
10389 if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
10390 if (IsNothrow)
10391 return ZeroInitialization(E);
10392
10393 Info.FFDiag(E: *ArraySize, DiagId: diag::note_constexpr_new_negative)
10394 << ArrayBound << (*ArraySize)->getSourceRange();
10395 return false;
10396 }
10397
10398 // -- its value is such that the size of the allocated object would
10399 // exceed the implementation-defined limit
10400 if (!Info.CheckArraySize(Loc: ArraySize.value()->getExprLoc(),
10401 BitWidth: ConstantArrayType::getNumAddressingBits(
10402 Context: Info.Ctx, ElementType: AllocType, NumElements: ArrayBound),
10403 ElemCount: ArrayBound.getZExtValue(), /*Diag=*/!IsNothrow)) {
10404 if (IsNothrow)
10405 return ZeroInitialization(E);
10406 return false;
10407 }
10408
10409 // -- the new-initializer is a braced-init-list and the number of
10410 // array elements for which initializers are provided [...]
10411 // exceeds the number of elements to initialize
10412 if (!Init) {
10413 // No initialization is performed.
10414 } else if (isa<CXXScalarValueInitExpr>(Val: Init) ||
10415 isa<ImplicitValueInitExpr>(Val: Init)) {
10416 ValueInit = true;
10417 } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Val: Init)) {
10418 ResizedArrayCCE = CCE;
10419 } else {
10420 auto *CAT = Info.Ctx.getAsConstantArrayType(T: Init->getType());
10421 assert(CAT && "unexpected type for array initializer");
10422
10423 unsigned Bits =
10424 std::max(a: CAT->getSizeBitWidth(), b: ArrayBound.getBitWidth());
10425 llvm::APInt InitBound = CAT->getSize().zext(width: Bits);
10426 llvm::APInt AllocBound = ArrayBound.zext(width: Bits);
10427 if (InitBound.ugt(RHS: AllocBound)) {
10428 if (IsNothrow)
10429 return ZeroInitialization(E);
10430
10431 Info.FFDiag(E: *ArraySize, DiagId: diag::note_constexpr_new_too_small)
10432 << toString(I: AllocBound, Radix: 10, /*Signed=*/false)
10433 << toString(I: InitBound, Radix: 10, /*Signed=*/false)
10434 << (*ArraySize)->getSourceRange();
10435 return false;
10436 }
10437
10438 // If the sizes differ, we must have an initializer list, and we need
10439 // special handling for this case when we initialize.
10440 if (InitBound != AllocBound)
10441 ResizedArrayILE = cast<InitListExpr>(Val: Init);
10442 }
10443
10444 AllocType = Info.Ctx.getConstantArrayType(EltTy: AllocType, ArySize: ArrayBound, SizeExpr: nullptr,
10445 ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
10446 } else {
10447 assert(!AllocType->isArrayType() &&
10448 "array allocation with non-array new");
10449 }
10450
10451 APValue *Val;
10452 if (IsPlacement) {
10453 AccessKinds AK = AK_Construct;
10454 struct FindObjectHandler {
10455 EvalInfo &Info;
10456 const Expr *E;
10457 QualType AllocType;
10458 const AccessKinds AccessKind;
10459 APValue *Value;
10460
10461 typedef bool result_type;
10462 bool failed() { return false; }
10463 bool checkConst(QualType QT) {
10464 if (QT.isConstQualified()) {
10465 Info.FFDiag(E, DiagId: diag::note_constexpr_modify_const_type) << QT;
10466 return false;
10467 }
10468 return true;
10469 }
10470 bool found(APValue &Subobj, QualType SubobjType) {
10471 if (!checkConst(QT: SubobjType))
10472 return false;
10473 // FIXME: Reject the cases where [basic.life]p8 would not permit the
10474 // old name of the object to be used to name the new object.
10475 unsigned SubobjectSize = 1;
10476 unsigned AllocSize = 1;
10477 if (auto *CAT = dyn_cast<ConstantArrayType>(Val&: AllocType))
10478 AllocSize = CAT->getZExtSize();
10479 if (auto *CAT = dyn_cast<ConstantArrayType>(Val&: SubobjType))
10480 SubobjectSize = CAT->getZExtSize();
10481 if (SubobjectSize < AllocSize ||
10482 !Info.Ctx.hasSimilarType(T1: Info.Ctx.getBaseElementType(QT: SubobjType),
10483 T2: Info.Ctx.getBaseElementType(QT: AllocType))) {
10484 Info.FFDiag(E, DiagId: diag::note_constexpr_placement_new_wrong_type)
10485 << SubobjType << AllocType;
10486 return false;
10487 }
10488 Value = &Subobj;
10489 return true;
10490 }
10491 bool found(APSInt &Value, QualType SubobjType) {
10492 Info.FFDiag(E, DiagId: diag::note_constexpr_construct_complex_elem);
10493 return false;
10494 }
10495 bool found(APFloat &Value, QualType SubobjType) {
10496 Info.FFDiag(E, DiagId: diag::note_constexpr_construct_complex_elem);
10497 return false;
10498 }
10499 } Handler = {.Info: Info, .E: E, .AllocType: AllocType, .AccessKind: AK, .Value: nullptr};
10500
10501 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal: Result, LValType: AllocType);
10502 if (!Obj || !findSubobject(Info, E, Obj, Sub: Result.Designator, handler&: Handler))
10503 return false;
10504
10505 Val = Handler.Value;
10506
10507 // [basic.life]p1:
10508 // The lifetime of an object o of type T ends when [...] the storage
10509 // which the object occupies is [...] reused by an object that is not
10510 // nested within o (6.6.2).
10511 *Val = APValue();
10512 } else {
10513 // Perform the allocation and obtain a pointer to the resulting object.
10514 Val = Info.createHeapAlloc(E, T: AllocType, LV&: Result);
10515 if (!Val)
10516 return false;
10517 }
10518
10519 if (ValueInit) {
10520 ImplicitValueInitExpr VIE(AllocType);
10521 if (!EvaluateInPlace(Result&: *Val, Info, This: Result, E: &VIE))
10522 return false;
10523 } else if (ResizedArrayILE) {
10524 if (!EvaluateArrayNewInitList(Info, This&: Result, Result&: *Val, ILE: ResizedArrayILE,
10525 AllocType))
10526 return false;
10527 } else if (ResizedArrayCCE) {
10528 if (!EvaluateArrayNewConstructExpr(Info, This&: Result, Result&: *Val, CCE: ResizedArrayCCE,
10529 AllocType))
10530 return false;
10531 } else if (Init) {
10532 if (!EvaluateInPlace(Result&: *Val, Info, This: Result, E: Init))
10533 return false;
10534 } else if (!handleDefaultInitValue(T: AllocType, Result&: *Val)) {
10535 return false;
10536 }
10537
10538 // Array new returns a pointer to the first element, not a pointer to the
10539 // array.
10540 if (auto *AT = AllocType->getAsArrayTypeUnsafe())
10541 Result.addArray(Info, E, CAT: cast<ConstantArrayType>(Val: AT));
10542
10543 return true;
10544}
10545//===----------------------------------------------------------------------===//
10546// Member Pointer Evaluation
10547//===----------------------------------------------------------------------===//
10548
10549namespace {
10550class MemberPointerExprEvaluator
10551 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
10552 MemberPtr &Result;
10553
10554 bool Success(const ValueDecl *D) {
10555 Result = MemberPtr(D);
10556 return true;
10557 }
10558public:
10559
10560 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
10561 : ExprEvaluatorBaseTy(Info), Result(Result) {}
10562
10563 bool Success(const APValue &V, const Expr *E) {
10564 Result.setFrom(V);
10565 return true;
10566 }
10567 bool ZeroInitialization(const Expr *E) {
10568 return Success(D: (const ValueDecl*)nullptr);
10569 }
10570
10571 bool VisitCastExpr(const CastExpr *E);
10572 bool VisitUnaryAddrOf(const UnaryOperator *E);
10573};
10574} // end anonymous namespace
10575
10576static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
10577 EvalInfo &Info) {
10578 assert(!E->isValueDependent());
10579 assert(E->isPRValue() && E->getType()->isMemberPointerType());
10580 return MemberPointerExprEvaluator(Info, Result).Visit(S: E);
10581}
10582
10583bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
10584 switch (E->getCastKind()) {
10585 default:
10586 return ExprEvaluatorBaseTy::VisitCastExpr(E);
10587
10588 case CK_NullToMemberPointer:
10589 VisitIgnoredValue(E: E->getSubExpr());
10590 return ZeroInitialization(E);
10591
10592 case CK_BaseToDerivedMemberPointer: {
10593 if (!Visit(S: E->getSubExpr()))
10594 return false;
10595 if (E->path_empty())
10596 return true;
10597 // Base-to-derived member pointer casts store the path in derived-to-base
10598 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
10599 // the wrong end of the derived->base arc, so stagger the path by one class.
10600 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
10601 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
10602 PathI != PathE; ++PathI) {
10603 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
10604 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
10605 if (!Result.castToDerived(Derived))
10606 return Error(E);
10607 }
10608 if (!Result.castToDerived(Derived: E->getType()
10609 ->castAs<MemberPointerType>()
10610 ->getMostRecentCXXRecordDecl()))
10611 return Error(E);
10612 return true;
10613 }
10614
10615 case CK_DerivedToBaseMemberPointer:
10616 if (!Visit(S: E->getSubExpr()))
10617 return false;
10618 for (CastExpr::path_const_iterator PathI = E->path_begin(),
10619 PathE = E->path_end(); PathI != PathE; ++PathI) {
10620 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
10621 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
10622 if (!Result.castToBase(Base))
10623 return Error(E);
10624 }
10625 return true;
10626 }
10627}
10628
10629bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
10630 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
10631 // member can be formed.
10632 return Success(D: cast<DeclRefExpr>(Val: E->getSubExpr())->getDecl());
10633}
10634
10635//===----------------------------------------------------------------------===//
10636// Record Evaluation
10637//===----------------------------------------------------------------------===//
10638
10639namespace {
10640 class RecordExprEvaluator
10641 : public ExprEvaluatorBase<RecordExprEvaluator> {
10642 const LValue &This;
10643 APValue &Result;
10644 public:
10645
10646 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
10647 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
10648
10649 bool Success(const APValue &V, const Expr *E) {
10650 Result = V;
10651 return true;
10652 }
10653 bool ZeroInitialization(const Expr *E) {
10654 return ZeroInitialization(E, T: E->getType());
10655 }
10656 bool ZeroInitialization(const Expr *E, QualType T);
10657
10658 bool VisitCallExpr(const CallExpr *E) {
10659 return handleCallExpr(E, Result, ResultSlot: &This);
10660 }
10661 bool VisitCastExpr(const CastExpr *E);
10662 bool VisitInitListExpr(const InitListExpr *E);
10663 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
10664 return VisitCXXConstructExpr(E, T: E->getType());
10665 }
10666 bool VisitLambdaExpr(const LambdaExpr *E);
10667 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
10668 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
10669 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
10670 bool VisitBinCmp(const BinaryOperator *E);
10671 bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E);
10672 bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit,
10673 ArrayRef<Expr *> Args);
10674 };
10675}
10676
10677/// Perform zero-initialization on an object of non-union class type.
10678/// C++11 [dcl.init]p5:
10679/// To zero-initialize an object or reference of type T means:
10680/// [...]
10681/// -- if T is a (possibly cv-qualified) non-union class type,
10682/// each non-static data member and each base-class subobject is
10683/// zero-initialized
10684static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
10685 const RecordDecl *RD,
10686 const LValue &This, APValue &Result) {
10687 assert(!RD->isUnion() && "Expected non-union class type");
10688 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(Val: RD);
10689 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
10690 std::distance(first: RD->field_begin(), last: RD->field_end()));
10691
10692 if (RD->isInvalidDecl()) return false;
10693 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
10694
10695 if (CD) {
10696 unsigned Index = 0;
10697 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
10698 End = CD->bases_end(); I != End; ++I, ++Index) {
10699 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
10700 LValue Subobject = This;
10701 if (!HandleLValueDirectBase(Info, E, Obj&: Subobject, Derived: CD, Base, RL: &Layout))
10702 return false;
10703 if (!HandleClassZeroInitialization(Info, E, RD: Base, This: Subobject,
10704 Result&: Result.getStructBase(i: Index)))
10705 return false;
10706 }
10707 }
10708
10709 for (const auto *I : RD->fields()) {
10710 // -- if T is a reference type, no initialization is performed.
10711 if (I->isUnnamedBitField() || I->getType()->isReferenceType())
10712 continue;
10713
10714 LValue Subobject = This;
10715 if (!HandleLValueMember(Info, E, LVal&: Subobject, FD: I, RL: &Layout))
10716 return false;
10717
10718 ImplicitValueInitExpr VIE(I->getType());
10719 if (!EvaluateInPlace(
10720 Result&: Result.getStructField(i: I->getFieldIndex()), Info, This: Subobject, E: &VIE))
10721 return false;
10722 }
10723
10724 return true;
10725}
10726
10727bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
10728 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
10729 if (RD->isInvalidDecl()) return false;
10730 if (RD->isUnion()) {
10731 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
10732 // object's first non-static named data member is zero-initialized
10733 RecordDecl::field_iterator I = RD->field_begin();
10734 while (I != RD->field_end() && (*I)->isUnnamedBitField())
10735 ++I;
10736 if (I == RD->field_end()) {
10737 Result = APValue((const FieldDecl*)nullptr);
10738 return true;
10739 }
10740
10741 LValue Subobject = This;
10742 if (!HandleLValueMember(Info, E, LVal&: Subobject, FD: *I))
10743 return false;
10744 Result = APValue(*I);
10745 ImplicitValueInitExpr VIE(I->getType());
10746 return EvaluateInPlace(Result&: Result.getUnionValue(), Info, This: Subobject, E: &VIE);
10747 }
10748
10749 if (isa<CXXRecordDecl>(Val: RD) && cast<CXXRecordDecl>(Val: RD)->getNumVBases()) {
10750 Info.FFDiag(E, DiagId: diag::note_constexpr_virtual_base) << RD;
10751 return false;
10752 }
10753
10754 return HandleClassZeroInitialization(Info, E, RD, This, Result);
10755}
10756
10757bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
10758 switch (E->getCastKind()) {
10759 default:
10760 return ExprEvaluatorBaseTy::VisitCastExpr(E);
10761
10762 case CK_ConstructorConversion:
10763 return Visit(S: E->getSubExpr());
10764
10765 case CK_DerivedToBase:
10766 case CK_UncheckedDerivedToBase: {
10767 APValue DerivedObject;
10768 if (!Evaluate(Result&: DerivedObject, Info, E: E->getSubExpr()))
10769 return false;
10770 if (!DerivedObject.isStruct())
10771 return Error(E: E->getSubExpr());
10772
10773 // Derived-to-base rvalue conversion: just slice off the derived part.
10774 APValue *Value = &DerivedObject;
10775 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
10776 for (CastExpr::path_const_iterator PathI = E->path_begin(),
10777 PathE = E->path_end(); PathI != PathE; ++PathI) {
10778 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
10779 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
10780 Value = &Value->getStructBase(i: getBaseIndex(Derived: RD, Base));
10781 RD = Base;
10782 }
10783 Result = *Value;
10784 return true;
10785 }
10786 }
10787}
10788
10789bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
10790 if (E->isTransparent())
10791 return Visit(S: E->getInit(Init: 0));
10792 return VisitCXXParenListOrInitListExpr(ExprToVisit: E, Args: E->inits());
10793}
10794
10795bool RecordExprEvaluator::VisitCXXParenListOrInitListExpr(
10796 const Expr *ExprToVisit, ArrayRef<Expr *> Args) {
10797 const RecordDecl *RD =
10798 ExprToVisit->getType()->castAs<RecordType>()->getDecl();
10799 if (RD->isInvalidDecl()) return false;
10800 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
10801 auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD);
10802
10803 EvalInfo::EvaluatingConstructorRAII EvalObj(
10804 Info,
10805 ObjectUnderConstruction{.Base: This.getLValueBase(), .Path: This.Designator.Entries},
10806 CXXRD && CXXRD->getNumBases());
10807
10808 if (RD->isUnion()) {
10809 const FieldDecl *Field;
10810 if (auto *ILE = dyn_cast<InitListExpr>(Val: ExprToVisit)) {
10811 Field = ILE->getInitializedFieldInUnion();
10812 } else if (auto *PLIE = dyn_cast<CXXParenListInitExpr>(Val: ExprToVisit)) {
10813 Field = PLIE->getInitializedFieldInUnion();
10814 } else {
10815 llvm_unreachable(
10816 "Expression is neither an init list nor a C++ paren list");
10817 }
10818
10819 Result = APValue(Field);
10820 if (!Field)
10821 return true;
10822
10823 // If the initializer list for a union does not contain any elements, the
10824 // first element of the union is value-initialized.
10825 // FIXME: The element should be initialized from an initializer list.
10826 // Is this difference ever observable for initializer lists which
10827 // we don't build?
10828 ImplicitValueInitExpr VIE(Field->getType());
10829 const Expr *InitExpr = Args.empty() ? &VIE : Args[0];
10830
10831 LValue Subobject = This;
10832 if (!HandleLValueMember(Info, E: InitExpr, LVal&: Subobject, FD: Field, RL: &Layout))
10833 return false;
10834
10835 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
10836 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
10837 isa<CXXDefaultInitExpr>(Val: InitExpr));
10838
10839 if (EvaluateInPlace(Result&: Result.getUnionValue(), Info, This: Subobject, E: InitExpr)) {
10840 if (Field->isBitField())
10841 return truncateBitfieldValue(Info, E: InitExpr, Value&: Result.getUnionValue(),
10842 FD: Field);
10843 return true;
10844 }
10845
10846 return false;
10847 }
10848
10849 if (!Result.hasValue())
10850 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
10851 std::distance(first: RD->field_begin(), last: RD->field_end()));
10852 unsigned ElementNo = 0;
10853 bool Success = true;
10854
10855 // Initialize base classes.
10856 if (CXXRD && CXXRD->getNumBases()) {
10857 for (const auto &Base : CXXRD->bases()) {
10858 assert(ElementNo < Args.size() && "missing init for base class");
10859 const Expr *Init = Args[ElementNo];
10860
10861 LValue Subobject = This;
10862 if (!HandleLValueBase(Info, E: Init, Obj&: Subobject, DerivedDecl: CXXRD, Base: &Base))
10863 return false;
10864
10865 APValue &FieldVal = Result.getStructBase(i: ElementNo);
10866 if (!EvaluateInPlace(Result&: FieldVal, Info, This: Subobject, E: Init)) {
10867 if (!Info.noteFailure())
10868 return false;
10869 Success = false;
10870 }
10871 ++ElementNo;
10872 }
10873
10874 EvalObj.finishedConstructingBases();
10875 }
10876
10877 // Initialize members.
10878 for (const auto *Field : RD->fields()) {
10879 // Anonymous bit-fields are not considered members of the class for
10880 // purposes of aggregate initialization.
10881 if (Field->isUnnamedBitField())
10882 continue;
10883
10884 LValue Subobject = This;
10885
10886 bool HaveInit = ElementNo < Args.size();
10887
10888 // FIXME: Diagnostics here should point to the end of the initializer
10889 // list, not the start.
10890 if (!HandleLValueMember(Info, E: HaveInit ? Args[ElementNo] : ExprToVisit,
10891 LVal&: Subobject, FD: Field, RL: &Layout))
10892 return false;
10893
10894 // Perform an implicit value-initialization for members beyond the end of
10895 // the initializer list.
10896 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
10897 const Expr *Init = HaveInit ? Args[ElementNo++] : &VIE;
10898
10899 if (Field->getType()->isIncompleteArrayType()) {
10900 if (auto *CAT = Info.Ctx.getAsConstantArrayType(T: Init->getType())) {
10901 if (!CAT->isZeroSize()) {
10902 // Bail out for now. This might sort of "work", but the rest of the
10903 // code isn't really prepared to handle it.
10904 Info.FFDiag(E: Init, DiagId: diag::note_constexpr_unsupported_flexible_array);
10905 return false;
10906 }
10907 }
10908 }
10909
10910 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
10911 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
10912 isa<CXXDefaultInitExpr>(Val: Init));
10913
10914 APValue &FieldVal = Result.getStructField(i: Field->getFieldIndex());
10915 if (!EvaluateInPlace(Result&: FieldVal, Info, This: Subobject, E: Init) ||
10916 (Field->isBitField() && !truncateBitfieldValue(Info, E: Init,
10917 Value&: FieldVal, FD: Field))) {
10918 if (!Info.noteFailure())
10919 return false;
10920 Success = false;
10921 }
10922 }
10923
10924 EvalObj.finishedConstructingFields();
10925
10926 return Success;
10927}
10928
10929bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
10930 QualType T) {
10931 // Note that E's type is not necessarily the type of our class here; we might
10932 // be initializing an array element instead.
10933 const CXXConstructorDecl *FD = E->getConstructor();
10934 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
10935
10936 bool ZeroInit = E->requiresZeroInitialization();
10937 if (CheckTrivialDefaultConstructor(Info, Loc: E->getExprLoc(), CD: FD, IsValueInitialization: ZeroInit)) {
10938 // If we've already performed zero-initialization, we're already done.
10939 if (Result.hasValue())
10940 return true;
10941
10942 if (ZeroInit)
10943 return ZeroInitialization(E, T);
10944
10945 return handleDefaultInitValue(T, Result);
10946 }
10947
10948 const FunctionDecl *Definition = nullptr;
10949 auto Body = FD->getBody(Definition);
10950
10951 if (!CheckConstexprFunction(Info, CallLoc: E->getExprLoc(), Declaration: FD, Definition, Body))
10952 return false;
10953
10954 // Avoid materializing a temporary for an elidable copy/move constructor.
10955 if (E->isElidable() && !ZeroInit) {
10956 // FIXME: This only handles the simplest case, where the source object
10957 // is passed directly as the first argument to the constructor.
10958 // This should also handle stepping though implicit casts and
10959 // and conversion sequences which involve two steps, with a
10960 // conversion operator followed by a converting constructor.
10961 const Expr *SrcObj = E->getArg(Arg: 0);
10962 assert(SrcObj->isTemporaryObject(Info.Ctx, FD->getParent()));
10963 assert(Info.Ctx.hasSameUnqualifiedType(E->getType(), SrcObj->getType()));
10964 if (const MaterializeTemporaryExpr *ME =
10965 dyn_cast<MaterializeTemporaryExpr>(Val: SrcObj))
10966 return Visit(S: ME->getSubExpr());
10967 }
10968
10969 if (ZeroInit && !ZeroInitialization(E, T))
10970 return false;
10971
10972 auto Args = ArrayRef(E->getArgs(), E->getNumArgs());
10973 return HandleConstructorCall(E, This, Args,
10974 Definition: cast<CXXConstructorDecl>(Val: Definition), Info,
10975 Result);
10976}
10977
10978bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
10979 const CXXInheritedCtorInitExpr *E) {
10980 if (!Info.CurrentCall) {
10981 assert(Info.checkingPotentialConstantExpression());
10982 return false;
10983 }
10984
10985 const CXXConstructorDecl *FD = E->getConstructor();
10986 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
10987 return false;
10988
10989 const FunctionDecl *Definition = nullptr;
10990 auto Body = FD->getBody(Definition);
10991
10992 if (!CheckConstexprFunction(Info, CallLoc: E->getExprLoc(), Declaration: FD, Definition, Body))
10993 return false;
10994
10995 return HandleConstructorCall(E, This, Call: Info.CurrentCall->Arguments,
10996 Definition: cast<CXXConstructorDecl>(Val: Definition), Info,
10997 Result);
10998}
10999
11000bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
11001 const CXXStdInitializerListExpr *E) {
11002 const ConstantArrayType *ArrayType =
11003 Info.Ctx.getAsConstantArrayType(T: E->getSubExpr()->getType());
11004
11005 LValue Array;
11006 if (!EvaluateLValue(E: E->getSubExpr(), Result&: Array, Info))
11007 return false;
11008
11009 assert(ArrayType && "unexpected type for array initializer");
11010
11011 // Get a pointer to the first element of the array.
11012 Array.addArray(Info, E, CAT: ArrayType);
11013
11014 // FIXME: What if the initializer_list type has base classes, etc?
11015 Result = APValue(APValue::UninitStruct(), 0, 2);
11016 Array.moveInto(V&: Result.getStructField(i: 0));
11017
11018 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
11019 RecordDecl::field_iterator Field = Record->field_begin();
11020 assert(Field != Record->field_end() &&
11021 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
11022 ArrayType->getElementType()) &&
11023 "Expected std::initializer_list first field to be const E *");
11024 ++Field;
11025 assert(Field != Record->field_end() &&
11026 "Expected std::initializer_list to have two fields");
11027
11028 if (Info.Ctx.hasSameType(T1: Field->getType(), T2: Info.Ctx.getSizeType())) {
11029 // Length.
11030 Result.getStructField(i: 1) = APValue(APSInt(ArrayType->getSize()));
11031 } else {
11032 // End pointer.
11033 assert(Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
11034 ArrayType->getElementType()) &&
11035 "Expected std::initializer_list second field to be const E *");
11036 if (!HandleLValueArrayAdjustment(Info, E, LVal&: Array,
11037 EltTy: ArrayType->getElementType(),
11038 Adjustment: ArrayType->getZExtSize()))
11039 return false;
11040 Array.moveInto(V&: Result.getStructField(i: 1));
11041 }
11042
11043 assert(++Field == Record->field_end() &&
11044 "Expected std::initializer_list to only have two fields");
11045
11046 return true;
11047}
11048
11049bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
11050 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
11051 if (ClosureClass->isInvalidDecl())
11052 return false;
11053
11054 const size_t NumFields =
11055 std::distance(first: ClosureClass->field_begin(), last: ClosureClass->field_end());
11056
11057 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
11058 E->capture_init_end()) &&
11059 "The number of lambda capture initializers should equal the number of "
11060 "fields within the closure type");
11061
11062 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
11063 // Iterate through all the lambda's closure object's fields and initialize
11064 // them.
11065 auto *CaptureInitIt = E->capture_init_begin();
11066 bool Success = true;
11067 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: ClosureClass);
11068 for (const auto *Field : ClosureClass->fields()) {
11069 assert(CaptureInitIt != E->capture_init_end());
11070 // Get the initializer for this field
11071 Expr *const CurFieldInit = *CaptureInitIt++;
11072
11073 // If there is no initializer, either this is a VLA or an error has
11074 // occurred.
11075 if (!CurFieldInit || CurFieldInit->containsErrors())
11076 return Error(E);
11077
11078 LValue Subobject = This;
11079
11080 if (!HandleLValueMember(Info, E, LVal&: Subobject, FD: Field, RL: &Layout))
11081 return false;
11082
11083 APValue &FieldVal = Result.getStructField(i: Field->getFieldIndex());
11084 if (!EvaluateInPlace(Result&: FieldVal, Info, This: Subobject, E: CurFieldInit)) {
11085 if (!Info.keepEvaluatingAfterFailure())
11086 return false;
11087 Success = false;
11088 }
11089 }
11090 return Success;
11091}
11092
11093static bool EvaluateRecord(const Expr *E, const LValue &This,
11094 APValue &Result, EvalInfo &Info) {
11095 assert(!E->isValueDependent());
11096 assert(E->isPRValue() && E->getType()->isRecordType() &&
11097 "can't evaluate expression as a record rvalue");
11098 return RecordExprEvaluator(Info, This, Result).Visit(S: E);
11099}
11100
11101//===----------------------------------------------------------------------===//
11102// Temporary Evaluation
11103//
11104// Temporaries are represented in the AST as rvalues, but generally behave like
11105// lvalues. The full-object of which the temporary is a subobject is implicitly
11106// materialized so that a reference can bind to it.
11107//===----------------------------------------------------------------------===//
11108namespace {
11109class TemporaryExprEvaluator
11110 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
11111public:
11112 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
11113 LValueExprEvaluatorBaseTy(Info, Result, false) {}
11114
11115 /// Visit an expression which constructs the value of this temporary.
11116 bool VisitConstructExpr(const Expr *E) {
11117 APValue &Value = Info.CurrentCall->createTemporary(
11118 Key: E, T: E->getType(), Scope: ScopeKind::FullExpression, LV&: Result);
11119 return EvaluateInPlace(Result&: Value, Info, This: Result, E);
11120 }
11121
11122 bool VisitCastExpr(const CastExpr *E) {
11123 switch (E->getCastKind()) {
11124 default:
11125 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
11126
11127 case CK_ConstructorConversion:
11128 return VisitConstructExpr(E: E->getSubExpr());
11129 }
11130 }
11131 bool VisitInitListExpr(const InitListExpr *E) {
11132 return VisitConstructExpr(E);
11133 }
11134 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
11135 return VisitConstructExpr(E);
11136 }
11137 bool VisitCallExpr(const CallExpr *E) {
11138 return VisitConstructExpr(E);
11139 }
11140 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
11141 return VisitConstructExpr(E);
11142 }
11143 bool VisitLambdaExpr(const LambdaExpr *E) {
11144 return VisitConstructExpr(E);
11145 }
11146};
11147} // end anonymous namespace
11148
11149/// Evaluate an expression of record type as a temporary.
11150static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
11151 assert(!E->isValueDependent());
11152 assert(E->isPRValue() && E->getType()->isRecordType());
11153 return TemporaryExprEvaluator(Info, Result).Visit(S: E);
11154}
11155
11156//===----------------------------------------------------------------------===//
11157// Vector Evaluation
11158//===----------------------------------------------------------------------===//
11159
11160namespace {
11161 class VectorExprEvaluator
11162 : public ExprEvaluatorBase<VectorExprEvaluator> {
11163 APValue &Result;
11164 public:
11165
11166 VectorExprEvaluator(EvalInfo &info, APValue &Result)
11167 : ExprEvaluatorBaseTy(info), Result(Result) {}
11168
11169 bool Success(ArrayRef<APValue> V, const Expr *E) {
11170 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
11171 // FIXME: remove this APValue copy.
11172 Result = APValue(V.data(), V.size());
11173 return true;
11174 }
11175 bool Success(const APValue &V, const Expr *E) {
11176 assert(V.isVector());
11177 Result = V;
11178 return true;
11179 }
11180 bool ZeroInitialization(const Expr *E);
11181
11182 bool VisitUnaryReal(const UnaryOperator *E)
11183 { return Visit(S: E->getSubExpr()); }
11184 bool VisitCastExpr(const CastExpr* E);
11185 bool VisitInitListExpr(const InitListExpr *E);
11186 bool VisitUnaryImag(const UnaryOperator *E);
11187 bool VisitBinaryOperator(const BinaryOperator *E);
11188 bool VisitUnaryOperator(const UnaryOperator *E);
11189 bool VisitCallExpr(const CallExpr *E);
11190 bool VisitConvertVectorExpr(const ConvertVectorExpr *E);
11191 bool VisitShuffleVectorExpr(const ShuffleVectorExpr *E);
11192
11193 // FIXME: Missing: conditional operator (for GNU
11194 // conditional select), ExtVectorElementExpr
11195 };
11196} // end anonymous namespace
11197
11198static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
11199 assert(E->isPRValue() && E->getType()->isVectorType() &&
11200 "not a vector prvalue");
11201 return VectorExprEvaluator(Info, Result).Visit(S: E);
11202}
11203
11204bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
11205 const VectorType *VTy = E->getType()->castAs<VectorType>();
11206 unsigned NElts = VTy->getNumElements();
11207
11208 const Expr *SE = E->getSubExpr();
11209 QualType SETy = SE->getType();
11210
11211 switch (E->getCastKind()) {
11212 case CK_VectorSplat: {
11213 APValue Val = APValue();
11214 if (SETy->isIntegerType()) {
11215 APSInt IntResult;
11216 if (!EvaluateInteger(E: SE, Result&: IntResult, Info))
11217 return false;
11218 Val = APValue(std::move(IntResult));
11219 } else if (SETy->isRealFloatingType()) {
11220 APFloat FloatResult(0.0);
11221 if (!EvaluateFloat(E: SE, Result&: FloatResult, Info))
11222 return false;
11223 Val = APValue(std::move(FloatResult));
11224 } else {
11225 return Error(E);
11226 }
11227
11228 // Splat and create vector APValue.
11229 SmallVector<APValue, 4> Elts(NElts, Val);
11230 return Success(V: Elts, E);
11231 }
11232 case CK_BitCast: {
11233 APValue SVal;
11234 if (!Evaluate(Result&: SVal, Info, E: SE))
11235 return false;
11236
11237 if (!SVal.isInt() && !SVal.isFloat() && !SVal.isVector()) {
11238 // Give up if the input isn't an int, float, or vector. For example, we
11239 // reject "(v4i16)(intptr_t)&a".
11240 Info.FFDiag(E, DiagId: diag::note_constexpr_invalid_cast)
11241 << diag::ConstexprInvalidCastKind::ThisConversionOrReinterpret
11242 << Info.Ctx.getLangOpts().CPlusPlus;
11243 return false;
11244 }
11245
11246 if (!handleRValueToRValueBitCast(Info, DestValue&: Result, SourceRValue: SVal, BCE: E))
11247 return false;
11248
11249 return true;
11250 }
11251 case CK_HLSLVectorTruncation: {
11252 APValue Val;
11253 SmallVector<APValue, 4> Elements;
11254 if (!EvaluateVector(E: SE, Result&: Val, Info))
11255 return Error(E);
11256 for (unsigned I = 0; I < NElts; I++)
11257 Elements.push_back(Elt: Val.getVectorElt(I));
11258 return Success(V: Elements, E);
11259 }
11260 default:
11261 return ExprEvaluatorBaseTy::VisitCastExpr(E);
11262 }
11263}
11264
11265bool
11266VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
11267 const VectorType *VT = E->getType()->castAs<VectorType>();
11268 unsigned NumInits = E->getNumInits();
11269 unsigned NumElements = VT->getNumElements();
11270
11271 QualType EltTy = VT->getElementType();
11272 SmallVector<APValue, 4> Elements;
11273
11274 // MFloat8 type doesn't have constants and thus constant folding
11275 // is impossible.
11276 if (EltTy->isMFloat8Type())
11277 return false;
11278
11279 // The number of initializers can be less than the number of
11280 // vector elements. For OpenCL, this can be due to nested vector
11281 // initialization. For GCC compatibility, missing trailing elements
11282 // should be initialized with zeroes.
11283 unsigned CountInits = 0, CountElts = 0;
11284 while (CountElts < NumElements) {
11285 // Handle nested vector initialization.
11286 if (CountInits < NumInits
11287 && E->getInit(Init: CountInits)->getType()->isVectorType()) {
11288 APValue v;
11289 if (!EvaluateVector(E: E->getInit(Init: CountInits), Result&: v, Info))
11290 return Error(E);
11291 unsigned vlen = v.getVectorLength();
11292 for (unsigned j = 0; j < vlen; j++)
11293 Elements.push_back(Elt: v.getVectorElt(I: j));
11294 CountElts += vlen;
11295 } else if (EltTy->isIntegerType()) {
11296 llvm::APSInt sInt(32);
11297 if (CountInits < NumInits) {
11298 if (!EvaluateInteger(E: E->getInit(Init: CountInits), Result&: sInt, Info))
11299 return false;
11300 } else // trailing integer zero.
11301 sInt = Info.Ctx.MakeIntValue(Value: 0, Type: EltTy);
11302 Elements.push_back(Elt: APValue(sInt));
11303 CountElts++;
11304 } else {
11305 llvm::APFloat f(0.0);
11306 if (CountInits < NumInits) {
11307 if (!EvaluateFloat(E: E->getInit(Init: CountInits), Result&: f, Info))
11308 return false;
11309 } else // trailing float zero.
11310 f = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: EltTy));
11311 Elements.push_back(Elt: APValue(f));
11312 CountElts++;
11313 }
11314 CountInits++;
11315 }
11316 return Success(V: Elements, E);
11317}
11318
11319bool
11320VectorExprEvaluator::ZeroInitialization(const Expr *E) {
11321 const auto *VT = E->getType()->castAs<VectorType>();
11322 QualType EltTy = VT->getElementType();
11323 APValue ZeroElement;
11324 if (EltTy->isIntegerType())
11325 ZeroElement = APValue(Info.Ctx.MakeIntValue(Value: 0, Type: EltTy));
11326 else
11327 ZeroElement =
11328 APValue(APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: EltTy)));
11329
11330 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
11331 return Success(V: Elements, E);
11332}
11333
11334bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
11335 VisitIgnoredValue(E: E->getSubExpr());
11336 return ZeroInitialization(E);
11337}
11338
11339bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
11340 BinaryOperatorKind Op = E->getOpcode();
11341 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&
11342 "Operation not supported on vector types");
11343
11344 if (Op == BO_Comma)
11345 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
11346
11347 Expr *LHS = E->getLHS();
11348 Expr *RHS = E->getRHS();
11349
11350 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&
11351 "Must both be vector types");
11352 // Checking JUST the types are the same would be fine, except shifts don't
11353 // need to have their types be the same (since you always shift by an int).
11354 assert(LHS->getType()->castAs<VectorType>()->getNumElements() ==
11355 E->getType()->castAs<VectorType>()->getNumElements() &&
11356 RHS->getType()->castAs<VectorType>()->getNumElements() ==
11357 E->getType()->castAs<VectorType>()->getNumElements() &&
11358 "All operands must be the same size.");
11359
11360 APValue LHSValue;
11361 APValue RHSValue;
11362 bool LHSOK = Evaluate(Result&: LHSValue, Info, E: LHS);
11363 if (!LHSOK && !Info.noteFailure())
11364 return false;
11365 if (!Evaluate(Result&: RHSValue, Info, E: RHS) || !LHSOK)
11366 return false;
11367
11368 if (!handleVectorVectorBinOp(Info, E, Opcode: Op, LHSValue, RHSValue))
11369 return false;
11370
11371 return Success(V: LHSValue, E);
11372}
11373
11374static std::optional<APValue> handleVectorUnaryOperator(ASTContext &Ctx,
11375 QualType ResultTy,
11376 UnaryOperatorKind Op,
11377 APValue Elt) {
11378 switch (Op) {
11379 case UO_Plus:
11380 // Nothing to do here.
11381 return Elt;
11382 case UO_Minus:
11383 if (Elt.getKind() == APValue::Int) {
11384 Elt.getInt().negate();
11385 } else {
11386 assert(Elt.getKind() == APValue::Float &&
11387 "Vector can only be int or float type");
11388 Elt.getFloat().changeSign();
11389 }
11390 return Elt;
11391 case UO_Not:
11392 // This is only valid for integral types anyway, so we don't have to handle
11393 // float here.
11394 assert(Elt.getKind() == APValue::Int &&
11395 "Vector operator ~ can only be int");
11396 Elt.getInt().flipAllBits();
11397 return Elt;
11398 case UO_LNot: {
11399 if (Elt.getKind() == APValue::Int) {
11400 Elt.getInt() = !Elt.getInt();
11401 // operator ! on vectors returns -1 for 'truth', so negate it.
11402 Elt.getInt().negate();
11403 return Elt;
11404 }
11405 assert(Elt.getKind() == APValue::Float &&
11406 "Vector can only be int or float type");
11407 // Float types result in an int of the same size, but -1 for true, or 0 for
11408 // false.
11409 APSInt EltResult{Ctx.getIntWidth(T: ResultTy),
11410 ResultTy->isUnsignedIntegerType()};
11411 if (Elt.getFloat().isZero())
11412 EltResult.setAllBits();
11413 else
11414 EltResult.clearAllBits();
11415
11416 return APValue{EltResult};
11417 }
11418 default:
11419 // FIXME: Implement the rest of the unary operators.
11420 return std::nullopt;
11421 }
11422}
11423
11424bool VectorExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
11425 Expr *SubExpr = E->getSubExpr();
11426 const auto *VD = SubExpr->getType()->castAs<VectorType>();
11427 // This result element type differs in the case of negating a floating point
11428 // vector, since the result type is the a vector of the equivilant sized
11429 // integer.
11430 const QualType ResultEltTy = VD->getElementType();
11431 UnaryOperatorKind Op = E->getOpcode();
11432
11433 APValue SubExprValue;
11434 if (!Evaluate(Result&: SubExprValue, Info, E: SubExpr))
11435 return false;
11436
11437 // FIXME: This vector evaluator someday needs to be changed to be LValue
11438 // aware/keep LValue information around, rather than dealing with just vector
11439 // types directly. Until then, we cannot handle cases where the operand to
11440 // these unary operators is an LValue. The only case I've been able to see
11441 // cause this is operator++ assigning to a member expression (only valid in
11442 // altivec compilations) in C mode, so this shouldn't limit us too much.
11443 if (SubExprValue.isLValue())
11444 return false;
11445
11446 assert(SubExprValue.getVectorLength() == VD->getNumElements() &&
11447 "Vector length doesn't match type?");
11448
11449 SmallVector<APValue, 4> ResultElements;
11450 for (unsigned EltNum = 0; EltNum < VD->getNumElements(); ++EltNum) {
11451 std::optional<APValue> Elt = handleVectorUnaryOperator(
11452 Ctx&: Info.Ctx, ResultTy: ResultEltTy, Op, Elt: SubExprValue.getVectorElt(I: EltNum));
11453 if (!Elt)
11454 return false;
11455 ResultElements.push_back(Elt: *Elt);
11456 }
11457 return Success(V: APValue(ResultElements.data(), ResultElements.size()), E);
11458}
11459
11460static bool handleVectorElementCast(EvalInfo &Info, const FPOptions FPO,
11461 const Expr *E, QualType SourceTy,
11462 QualType DestTy, APValue const &Original,
11463 APValue &Result) {
11464 if (SourceTy->isIntegerType()) {
11465 if (DestTy->isRealFloatingType()) {
11466 Result = APValue(APFloat(0.0));
11467 return HandleIntToFloatCast(Info, E, FPO, SrcType: SourceTy, Value: Original.getInt(),
11468 DestType: DestTy, Result&: Result.getFloat());
11469 }
11470 if (DestTy->isIntegerType()) {
11471 Result = APValue(
11472 HandleIntToIntCast(Info, E, DestType: DestTy, SrcType: SourceTy, Value: Original.getInt()));
11473 return true;
11474 }
11475 } else if (SourceTy->isRealFloatingType()) {
11476 if (DestTy->isRealFloatingType()) {
11477 Result = Original;
11478 return HandleFloatToFloatCast(Info, E, SrcType: SourceTy, DestType: DestTy,
11479 Result&: Result.getFloat());
11480 }
11481 if (DestTy->isIntegerType()) {
11482 Result = APValue(APSInt());
11483 return HandleFloatToIntCast(Info, E, SrcType: SourceTy, Value: Original.getFloat(),
11484 DestType: DestTy, Result&: Result.getInt());
11485 }
11486 }
11487
11488 Info.FFDiag(E, DiagId: diag::err_convertvector_constexpr_unsupported_vector_cast)
11489 << SourceTy << DestTy;
11490 return false;
11491}
11492
11493bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
11494 if (!IsConstantEvaluatedBuiltinCall(E))
11495 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11496
11497 switch (E->getBuiltinCallee()) {
11498 default:
11499 return false;
11500 case Builtin::BI__builtin_elementwise_popcount:
11501 case Builtin::BI__builtin_elementwise_bitreverse: {
11502 APValue Source;
11503 if (!EvaluateAsRValue(Info, E: E->getArg(Arg: 0), Result&: Source))
11504 return false;
11505
11506 QualType DestEltTy = E->getType()->castAs<VectorType>()->getElementType();
11507 unsigned SourceLen = Source.getVectorLength();
11508 SmallVector<APValue, 4> ResultElements;
11509 ResultElements.reserve(N: SourceLen);
11510
11511 for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
11512 APSInt Elt = Source.getVectorElt(I: EltNum).getInt();
11513 switch (E->getBuiltinCallee()) {
11514 case Builtin::BI__builtin_elementwise_popcount:
11515 ResultElements.push_back(Elt: APValue(
11516 APSInt(APInt(Info.Ctx.getIntWidth(T: DestEltTy), Elt.popcount()),
11517 DestEltTy->isUnsignedIntegerOrEnumerationType())));
11518 break;
11519 case Builtin::BI__builtin_elementwise_bitreverse:
11520 ResultElements.push_back(
11521 Elt: APValue(APSInt(Elt.reverseBits(),
11522 DestEltTy->isUnsignedIntegerOrEnumerationType())));
11523 break;
11524 }
11525 }
11526
11527 return Success(V: APValue(ResultElements.data(), ResultElements.size()), E);
11528 }
11529 case Builtin::BI__builtin_elementwise_add_sat:
11530 case Builtin::BI__builtin_elementwise_sub_sat: {
11531 APValue SourceLHS, SourceRHS;
11532 if (!EvaluateAsRValue(Info, E: E->getArg(Arg: 0), Result&: SourceLHS) ||
11533 !EvaluateAsRValue(Info, E: E->getArg(Arg: 1), Result&: SourceRHS))
11534 return false;
11535
11536 QualType DestEltTy = E->getType()->castAs<VectorType>()->getElementType();
11537 unsigned SourceLen = SourceLHS.getVectorLength();
11538 SmallVector<APValue, 4> ResultElements;
11539 ResultElements.reserve(N: SourceLen);
11540
11541 for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
11542 APSInt LHS = SourceLHS.getVectorElt(I: EltNum).getInt();
11543 APSInt RHS = SourceRHS.getVectorElt(I: EltNum).getInt();
11544 switch (E->getBuiltinCallee()) {
11545 case Builtin::BI__builtin_elementwise_add_sat:
11546 ResultElements.push_back(Elt: APValue(
11547 APSInt(LHS.isSigned() ? LHS.sadd_sat(RHS) : RHS.uadd_sat(RHS),
11548 DestEltTy->isUnsignedIntegerOrEnumerationType())));
11549 break;
11550 case Builtin::BI__builtin_elementwise_sub_sat:
11551 ResultElements.push_back(Elt: APValue(
11552 APSInt(LHS.isSigned() ? LHS.ssub_sat(RHS) : RHS.usub_sat(RHS),
11553 DestEltTy->isUnsignedIntegerOrEnumerationType())));
11554 break;
11555 }
11556 }
11557
11558 return Success(V: APValue(ResultElements.data(), ResultElements.size()), E);
11559 }
11560 }
11561}
11562
11563bool VectorExprEvaluator::VisitConvertVectorExpr(const ConvertVectorExpr *E) {
11564 APValue Source;
11565 QualType SourceVecType = E->getSrcExpr()->getType();
11566 if (!EvaluateAsRValue(Info, E: E->getSrcExpr(), Result&: Source))
11567 return false;
11568
11569 QualType DestTy = E->getType()->castAs<VectorType>()->getElementType();
11570 QualType SourceTy = SourceVecType->castAs<VectorType>()->getElementType();
11571
11572 const FPOptions FPO = E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts());
11573
11574 auto SourceLen = Source.getVectorLength();
11575 SmallVector<APValue, 4> ResultElements;
11576 ResultElements.reserve(N: SourceLen);
11577 for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
11578 APValue Elt;
11579 if (!handleVectorElementCast(Info, FPO, E, SourceTy, DestTy,
11580 Original: Source.getVectorElt(I: EltNum), Result&: Elt))
11581 return false;
11582 ResultElements.push_back(Elt: std::move(Elt));
11583 }
11584
11585 return Success(V: APValue(ResultElements.data(), ResultElements.size()), E);
11586}
11587
11588static bool handleVectorShuffle(EvalInfo &Info, const ShuffleVectorExpr *E,
11589 QualType ElemType, APValue const &VecVal1,
11590 APValue const &VecVal2, unsigned EltNum,
11591 APValue &Result) {
11592 unsigned const TotalElementsInInputVector1 = VecVal1.getVectorLength();
11593 unsigned const TotalElementsInInputVector2 = VecVal2.getVectorLength();
11594
11595 APSInt IndexVal = E->getShuffleMaskIdx(N: EltNum);
11596 int64_t index = IndexVal.getExtValue();
11597 // The spec says that -1 should be treated as undef for optimizations,
11598 // but in constexpr we'd have to produce an APValue::Indeterminate,
11599 // which is prohibited from being a top-level constant value. Emit a
11600 // diagnostic instead.
11601 if (index == -1) {
11602 Info.FFDiag(
11603 E, DiagId: diag::err_shufflevector_minus_one_is_undefined_behavior_constexpr)
11604 << EltNum;
11605 return false;
11606 }
11607
11608 if (index < 0 ||
11609 index >= TotalElementsInInputVector1 + TotalElementsInInputVector2)
11610 llvm_unreachable("Out of bounds shuffle index");
11611
11612 if (index >= TotalElementsInInputVector1)
11613 Result = VecVal2.getVectorElt(I: index - TotalElementsInInputVector1);
11614 else
11615 Result = VecVal1.getVectorElt(I: index);
11616 return true;
11617}
11618
11619bool VectorExprEvaluator::VisitShuffleVectorExpr(const ShuffleVectorExpr *E) {
11620 APValue VecVal1;
11621 const Expr *Vec1 = E->getExpr(Index: 0);
11622 if (!EvaluateAsRValue(Info, E: Vec1, Result&: VecVal1))
11623 return false;
11624 APValue VecVal2;
11625 const Expr *Vec2 = E->getExpr(Index: 1);
11626 if (!EvaluateAsRValue(Info, E: Vec2, Result&: VecVal2))
11627 return false;
11628
11629 VectorType const *DestVecTy = E->getType()->castAs<VectorType>();
11630 QualType DestElTy = DestVecTy->getElementType();
11631
11632 auto TotalElementsInOutputVector = DestVecTy->getNumElements();
11633
11634 SmallVector<APValue, 4> ResultElements;
11635 ResultElements.reserve(N: TotalElementsInOutputVector);
11636 for (unsigned EltNum = 0; EltNum < TotalElementsInOutputVector; ++EltNum) {
11637 APValue Elt;
11638 if (!handleVectorShuffle(Info, E, ElemType: DestElTy, VecVal1, VecVal2, EltNum, Result&: Elt))
11639 return false;
11640 ResultElements.push_back(Elt: std::move(Elt));
11641 }
11642
11643 return Success(V: APValue(ResultElements.data(), ResultElements.size()), E);
11644}
11645
11646//===----------------------------------------------------------------------===//
11647// Array Evaluation
11648//===----------------------------------------------------------------------===//
11649
11650namespace {
11651 class ArrayExprEvaluator
11652 : public ExprEvaluatorBase<ArrayExprEvaluator> {
11653 const LValue &This;
11654 APValue &Result;
11655 public:
11656
11657 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
11658 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
11659
11660 bool Success(const APValue &V, const Expr *E) {
11661 assert(V.isArray() && "expected array");
11662 Result = V;
11663 return true;
11664 }
11665
11666 bool ZeroInitialization(const Expr *E) {
11667 const ConstantArrayType *CAT =
11668 Info.Ctx.getAsConstantArrayType(T: E->getType());
11669 if (!CAT) {
11670 if (E->getType()->isIncompleteArrayType()) {
11671 // We can be asked to zero-initialize a flexible array member; this
11672 // is represented as an ImplicitValueInitExpr of incomplete array
11673 // type. In this case, the array has zero elements.
11674 Result = APValue(APValue::UninitArray(), 0, 0);
11675 return true;
11676 }
11677 // FIXME: We could handle VLAs here.
11678 return Error(E);
11679 }
11680
11681 Result = APValue(APValue::UninitArray(), 0, CAT->getZExtSize());
11682 if (!Result.hasArrayFiller())
11683 return true;
11684
11685 // Zero-initialize all elements.
11686 LValue Subobject = This;
11687 Subobject.addArray(Info, E, CAT);
11688 ImplicitValueInitExpr VIE(CAT->getElementType());
11689 return EvaluateInPlace(Result&: Result.getArrayFiller(), Info, This: Subobject, E: &VIE);
11690 }
11691
11692 bool VisitCallExpr(const CallExpr *E) {
11693 return handleCallExpr(E, Result, ResultSlot: &This);
11694 }
11695 bool VisitInitListExpr(const InitListExpr *E,
11696 QualType AllocType = QualType());
11697 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
11698 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
11699 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
11700 const LValue &Subobject,
11701 APValue *Value, QualType Type);
11702 bool VisitStringLiteral(const StringLiteral *E,
11703 QualType AllocType = QualType()) {
11704 expandStringLiteral(Info, S: E, Result, AllocType);
11705 return true;
11706 }
11707 bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E);
11708 bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit,
11709 ArrayRef<Expr *> Args,
11710 const Expr *ArrayFiller,
11711 QualType AllocType = QualType());
11712 };
11713} // end anonymous namespace
11714
11715static bool EvaluateArray(const Expr *E, const LValue &This,
11716 APValue &Result, EvalInfo &Info) {
11717 assert(!E->isValueDependent());
11718 assert(E->isPRValue() && E->getType()->isArrayType() &&
11719 "not an array prvalue");
11720 return ArrayExprEvaluator(Info, This, Result).Visit(S: E);
11721}
11722
11723static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
11724 APValue &Result, const InitListExpr *ILE,
11725 QualType AllocType) {
11726 assert(!ILE->isValueDependent());
11727 assert(ILE->isPRValue() && ILE->getType()->isArrayType() &&
11728 "not an array prvalue");
11729 return ArrayExprEvaluator(Info, This, Result)
11730 .VisitInitListExpr(E: ILE, AllocType);
11731}
11732
11733static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
11734 APValue &Result,
11735 const CXXConstructExpr *CCE,
11736 QualType AllocType) {
11737 assert(!CCE->isValueDependent());
11738 assert(CCE->isPRValue() && CCE->getType()->isArrayType() &&
11739 "not an array prvalue");
11740 return ArrayExprEvaluator(Info, This, Result)
11741 .VisitCXXConstructExpr(E: CCE, Subobject: This, Value: &Result, Type: AllocType);
11742}
11743
11744// Return true iff the given array filler may depend on the element index.
11745static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
11746 // For now, just allow non-class value-initialization and initialization
11747 // lists comprised of them.
11748 if (isa<ImplicitValueInitExpr>(Val: FillerExpr))
11749 return false;
11750 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Val: FillerExpr)) {
11751 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
11752 if (MaybeElementDependentArrayFiller(FillerExpr: ILE->getInit(Init: I)))
11753 return true;
11754 }
11755
11756 if (ILE->hasArrayFiller() &&
11757 MaybeElementDependentArrayFiller(FillerExpr: ILE->getArrayFiller()))
11758 return true;
11759
11760 return false;
11761 }
11762 return true;
11763}
11764
11765bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
11766 QualType AllocType) {
11767 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
11768 T: AllocType.isNull() ? E->getType() : AllocType);
11769 if (!CAT)
11770 return Error(E);
11771
11772 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
11773 // an appropriately-typed string literal enclosed in braces.
11774 if (E->isStringLiteralInit()) {
11775 auto *SL = dyn_cast<StringLiteral>(Val: E->getInit(Init: 0)->IgnoreParenImpCasts());
11776 // FIXME: Support ObjCEncodeExpr here once we support it in
11777 // ArrayExprEvaluator generally.
11778 if (!SL)
11779 return Error(E);
11780 return VisitStringLiteral(E: SL, AllocType);
11781 }
11782 // Any other transparent list init will need proper handling of the
11783 // AllocType; we can't just recurse to the inner initializer.
11784 assert(!E->isTransparent() &&
11785 "transparent array list initialization is not string literal init?");
11786
11787 return VisitCXXParenListOrInitListExpr(ExprToVisit: E, Args: E->inits(), ArrayFiller: E->getArrayFiller(),
11788 AllocType);
11789}
11790
11791bool ArrayExprEvaluator::VisitCXXParenListOrInitListExpr(
11792 const Expr *ExprToVisit, ArrayRef<Expr *> Args, const Expr *ArrayFiller,
11793 QualType AllocType) {
11794 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
11795 T: AllocType.isNull() ? ExprToVisit->getType() : AllocType);
11796
11797 bool Success = true;
11798
11799 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
11800 "zero-initialized array shouldn't have any initialized elts");
11801 APValue Filler;
11802 if (Result.isArray() && Result.hasArrayFiller())
11803 Filler = Result.getArrayFiller();
11804
11805 unsigned NumEltsToInit = Args.size();
11806 unsigned NumElts = CAT->getZExtSize();
11807
11808 // If the initializer might depend on the array index, run it for each
11809 // array element.
11810 if (NumEltsToInit != NumElts &&
11811 MaybeElementDependentArrayFiller(FillerExpr: ArrayFiller)) {
11812 NumEltsToInit = NumElts;
11813 } else {
11814 for (auto *Init : Args) {
11815 if (auto *EmbedS = dyn_cast<EmbedExpr>(Val: Init->IgnoreParenImpCasts()))
11816 NumEltsToInit += EmbedS->getDataElementCount() - 1;
11817 }
11818 if (NumEltsToInit > NumElts)
11819 NumEltsToInit = NumElts;
11820 }
11821
11822 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "
11823 << NumEltsToInit << ".\n");
11824
11825 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
11826
11827 // If the array was previously zero-initialized, preserve the
11828 // zero-initialized values.
11829 if (Filler.hasValue()) {
11830 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
11831 Result.getArrayInitializedElt(I) = Filler;
11832 if (Result.hasArrayFiller())
11833 Result.getArrayFiller() = Filler;
11834 }
11835
11836 LValue Subobject = This;
11837 Subobject.addArray(Info, E: ExprToVisit, CAT);
11838 auto Eval = [&](const Expr *Init, unsigned ArrayIndex) {
11839 if (Init->isValueDependent())
11840 return EvaluateDependentExpr(E: Init, Info);
11841
11842 if (!EvaluateInPlace(Result&: Result.getArrayInitializedElt(I: ArrayIndex), Info,
11843 This: Subobject, E: Init) ||
11844 !HandleLValueArrayAdjustment(Info, E: Init, LVal&: Subobject,
11845 EltTy: CAT->getElementType(), Adjustment: 1)) {
11846 if (!Info.noteFailure())
11847 return false;
11848 Success = false;
11849 }
11850 return true;
11851 };
11852 unsigned ArrayIndex = 0;
11853 QualType DestTy = CAT->getElementType();
11854 APSInt Value(Info.Ctx.getTypeSize(T: DestTy), DestTy->isUnsignedIntegerType());
11855 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
11856 const Expr *Init = Index < Args.size() ? Args[Index] : ArrayFiller;
11857 if (ArrayIndex >= NumEltsToInit)
11858 break;
11859 if (auto *EmbedS = dyn_cast<EmbedExpr>(Val: Init->IgnoreParenImpCasts())) {
11860 StringLiteral *SL = EmbedS->getDataStringLiteral();
11861 for (unsigned I = EmbedS->getStartingElementPos(),
11862 N = EmbedS->getDataElementCount();
11863 I != EmbedS->getStartingElementPos() + N; ++I) {
11864 Value = SL->getCodeUnit(i: I);
11865 if (DestTy->isIntegerType()) {
11866 Result.getArrayInitializedElt(I: ArrayIndex) = APValue(Value);
11867 } else {
11868 assert(DestTy->isFloatingType() && "unexpected type");
11869 const FPOptions FPO =
11870 Init->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts());
11871 APFloat FValue(0.0);
11872 if (!HandleIntToFloatCast(Info, E: Init, FPO, SrcType: EmbedS->getType(), Value,
11873 DestType: DestTy, Result&: FValue))
11874 return false;
11875 Result.getArrayInitializedElt(I: ArrayIndex) = APValue(FValue);
11876 }
11877 ArrayIndex++;
11878 }
11879 } else {
11880 if (!Eval(Init, ArrayIndex))
11881 return false;
11882 ++ArrayIndex;
11883 }
11884 }
11885
11886 if (!Result.hasArrayFiller())
11887 return Success;
11888
11889 // If we get here, we have a trivial filler, which we can just evaluate
11890 // once and splat over the rest of the array elements.
11891 assert(ArrayFiller && "no array filler for incomplete init list");
11892 return EvaluateInPlace(Result&: Result.getArrayFiller(), Info, This: Subobject,
11893 E: ArrayFiller) &&
11894 Success;
11895}
11896
11897bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
11898 LValue CommonLV;
11899 if (E->getCommonExpr() &&
11900 !Evaluate(Result&: Info.CurrentCall->createTemporary(
11901 Key: E->getCommonExpr(),
11902 T: getStorageType(Ctx: Info.Ctx, E: E->getCommonExpr()),
11903 Scope: ScopeKind::FullExpression, LV&: CommonLV),
11904 Info, E: E->getCommonExpr()->getSourceExpr()))
11905 return false;
11906
11907 auto *CAT = cast<ConstantArrayType>(Val: E->getType()->castAsArrayTypeUnsafe());
11908
11909 uint64_t Elements = CAT->getZExtSize();
11910 Result = APValue(APValue::UninitArray(), Elements, Elements);
11911
11912 LValue Subobject = This;
11913 Subobject.addArray(Info, E, CAT);
11914
11915 bool Success = true;
11916 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
11917 // C++ [class.temporary]/5
11918 // There are four contexts in which temporaries are destroyed at a different
11919 // point than the end of the full-expression. [...] The second context is
11920 // when a copy constructor is called to copy an element of an array while
11921 // the entire array is copied [...]. In either case, if the constructor has
11922 // one or more default arguments, the destruction of every temporary created
11923 // in a default argument is sequenced before the construction of the next
11924 // array element, if any.
11925 FullExpressionRAII Scope(Info);
11926
11927 if (!EvaluateInPlace(Result&: Result.getArrayInitializedElt(I: Index),
11928 Info, This: Subobject, E: E->getSubExpr()) ||
11929 !HandleLValueArrayAdjustment(Info, E, LVal&: Subobject,
11930 EltTy: CAT->getElementType(), Adjustment: 1)) {
11931 if (!Info.noteFailure())
11932 return false;
11933 Success = false;
11934 }
11935
11936 // Make sure we run the destructors too.
11937 Scope.destroy();
11938 }
11939
11940 return Success;
11941}
11942
11943bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
11944 return VisitCXXConstructExpr(E, Subobject: This, Value: &Result, Type: E->getType());
11945}
11946
11947bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
11948 const LValue &Subobject,
11949 APValue *Value,
11950 QualType Type) {
11951 bool HadZeroInit = Value->hasValue();
11952
11953 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T: Type)) {
11954 unsigned FinalSize = CAT->getZExtSize();
11955
11956 // Preserve the array filler if we had prior zero-initialization.
11957 APValue Filler =
11958 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
11959 : APValue();
11960
11961 *Value = APValue(APValue::UninitArray(), 0, FinalSize);
11962 if (FinalSize == 0)
11963 return true;
11964
11965 bool HasTrivialConstructor = CheckTrivialDefaultConstructor(
11966 Info, Loc: E->getExprLoc(), CD: E->getConstructor(),
11967 IsValueInitialization: E->requiresZeroInitialization());
11968 LValue ArrayElt = Subobject;
11969 ArrayElt.addArray(Info, E, CAT);
11970 // We do the whole initialization in two passes, first for just one element,
11971 // then for the whole array. It's possible we may find out we can't do const
11972 // init in the first pass, in which case we avoid allocating a potentially
11973 // large array. We don't do more passes because expanding array requires
11974 // copying the data, which is wasteful.
11975 for (const unsigned N : {1u, FinalSize}) {
11976 unsigned OldElts = Value->getArrayInitializedElts();
11977 if (OldElts == N)
11978 break;
11979
11980 // Expand the array to appropriate size.
11981 APValue NewValue(APValue::UninitArray(), N, FinalSize);
11982 for (unsigned I = 0; I < OldElts; ++I)
11983 NewValue.getArrayInitializedElt(I).swap(
11984 RHS&: Value->getArrayInitializedElt(I));
11985 Value->swap(RHS&: NewValue);
11986
11987 if (HadZeroInit)
11988 for (unsigned I = OldElts; I < N; ++I)
11989 Value->getArrayInitializedElt(I) = Filler;
11990
11991 if (HasTrivialConstructor && N == FinalSize && FinalSize != 1) {
11992 // If we have a trivial constructor, only evaluate it once and copy
11993 // the result into all the array elements.
11994 APValue &FirstResult = Value->getArrayInitializedElt(I: 0);
11995 for (unsigned I = OldElts; I < FinalSize; ++I)
11996 Value->getArrayInitializedElt(I) = FirstResult;
11997 } else {
11998 for (unsigned I = OldElts; I < N; ++I) {
11999 if (!VisitCXXConstructExpr(E, Subobject: ArrayElt,
12000 Value: &Value->getArrayInitializedElt(I),
12001 Type: CAT->getElementType()) ||
12002 !HandleLValueArrayAdjustment(Info, E, LVal&: ArrayElt,
12003 EltTy: CAT->getElementType(), Adjustment: 1))
12004 return false;
12005 // When checking for const initilization any diagnostic is considered
12006 // an error.
12007 if (Info.EvalStatus.Diag && !Info.EvalStatus.Diag->empty() &&
12008 !Info.keepEvaluatingAfterFailure())
12009 return false;
12010 }
12011 }
12012 }
12013
12014 return true;
12015 }
12016
12017 if (!Type->isRecordType())
12018 return Error(E);
12019
12020 return RecordExprEvaluator(Info, Subobject, *Value)
12021 .VisitCXXConstructExpr(E, T: Type);
12022}
12023
12024bool ArrayExprEvaluator::VisitCXXParenListInitExpr(
12025 const CXXParenListInitExpr *E) {
12026 assert(E->getType()->isConstantArrayType() &&
12027 "Expression result is not a constant array type");
12028
12029 return VisitCXXParenListOrInitListExpr(ExprToVisit: E, Args: E->getInitExprs(),
12030 ArrayFiller: E->getArrayFiller());
12031}
12032
12033//===----------------------------------------------------------------------===//
12034// Integer Evaluation
12035//
12036// As a GNU extension, we support casting pointers to sufficiently-wide integer
12037// types and back in constant folding. Integer values are thus represented
12038// either as an integer-valued APValue, or as an lvalue-valued APValue.
12039//===----------------------------------------------------------------------===//
12040
12041namespace {
12042class IntExprEvaluator
12043 : public ExprEvaluatorBase<IntExprEvaluator> {
12044 APValue &Result;
12045public:
12046 IntExprEvaluator(EvalInfo &info, APValue &result)
12047 : ExprEvaluatorBaseTy(info), Result(result) {}
12048
12049 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
12050 assert(E->getType()->isIntegralOrEnumerationType() &&
12051 "Invalid evaluation result.");
12052 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
12053 "Invalid evaluation result.");
12054 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
12055 "Invalid evaluation result.");
12056 Result = APValue(SI);
12057 return true;
12058 }
12059 bool Success(const llvm::APSInt &SI, const Expr *E) {
12060 return Success(SI, E, Result);
12061 }
12062
12063 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
12064 assert(E->getType()->isIntegralOrEnumerationType() &&
12065 "Invalid evaluation result.");
12066 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
12067 "Invalid evaluation result.");
12068 Result = APValue(APSInt(I));
12069 Result.getInt().setIsUnsigned(
12070 E->getType()->isUnsignedIntegerOrEnumerationType());
12071 return true;
12072 }
12073 bool Success(const llvm::APInt &I, const Expr *E) {
12074 return Success(I, E, Result);
12075 }
12076
12077 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
12078 assert(E->getType()->isIntegralOrEnumerationType() &&
12079 "Invalid evaluation result.");
12080 Result = APValue(Info.Ctx.MakeIntValue(Value, Type: E->getType()));
12081 return true;
12082 }
12083 bool Success(uint64_t Value, const Expr *E) {
12084 return Success(Value, E, Result);
12085 }
12086
12087 bool Success(CharUnits Size, const Expr *E) {
12088 return Success(Value: Size.getQuantity(), E);
12089 }
12090
12091 bool Success(const APValue &V, const Expr *E) {
12092 // C++23 [expr.const]p8 If we have a variable that is unknown reference or
12093 // pointer allow further evaluation of the value.
12094 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate() ||
12095 V.allowConstexprUnknown()) {
12096 Result = V;
12097 return true;
12098 }
12099 return Success(SI: V.getInt(), E);
12100 }
12101
12102 bool ZeroInitialization(const Expr *E) { return Success(Value: 0, E); }
12103
12104 friend std::optional<bool> EvaluateBuiltinIsWithinLifetime(IntExprEvaluator &,
12105 const CallExpr *);
12106
12107 //===--------------------------------------------------------------------===//
12108 // Visitor Methods
12109 //===--------------------------------------------------------------------===//
12110
12111 bool VisitIntegerLiteral(const IntegerLiteral *E) {
12112 return Success(I: E->getValue(), E);
12113 }
12114 bool VisitCharacterLiteral(const CharacterLiteral *E) {
12115 return Success(Value: E->getValue(), E);
12116 }
12117
12118 bool CheckReferencedDecl(const Expr *E, const Decl *D);
12119 bool VisitDeclRefExpr(const DeclRefExpr *E) {
12120 if (CheckReferencedDecl(E, D: E->getDecl()))
12121 return true;
12122
12123 return ExprEvaluatorBaseTy::VisitDeclRefExpr(S: E);
12124 }
12125 bool VisitMemberExpr(const MemberExpr *E) {
12126 if (CheckReferencedDecl(E, D: E->getMemberDecl())) {
12127 VisitIgnoredBaseExpression(E: E->getBase());
12128 return true;
12129 }
12130
12131 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
12132 }
12133
12134 bool VisitCallExpr(const CallExpr *E);
12135 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
12136 bool VisitBinaryOperator(const BinaryOperator *E);
12137 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
12138 bool VisitUnaryOperator(const UnaryOperator *E);
12139
12140 bool VisitCastExpr(const CastExpr* E);
12141 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
12142
12143 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
12144 return Success(Value: E->getValue(), E);
12145 }
12146
12147 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
12148 return Success(Value: E->getValue(), E);
12149 }
12150
12151 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
12152 if (Info.ArrayInitIndex == uint64_t(-1)) {
12153 // We were asked to evaluate this subexpression independent of the
12154 // enclosing ArrayInitLoopExpr. We can't do that.
12155 Info.FFDiag(E);
12156 return false;
12157 }
12158 return Success(Value: Info.ArrayInitIndex, E);
12159 }
12160
12161 // Note, GNU defines __null as an integer, not a pointer.
12162 bool VisitGNUNullExpr(const GNUNullExpr *E) {
12163 return ZeroInitialization(E);
12164 }
12165
12166 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
12167 if (E->isStoredAsBoolean())
12168 return Success(Value: E->getBoolValue(), E);
12169 if (E->getAPValue().isAbsent())
12170 return false;
12171 assert(E->getAPValue().isInt() && "APValue type not supported");
12172 return Success(SI: E->getAPValue().getInt(), E);
12173 }
12174
12175 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
12176 return Success(Value: E->getValue(), E);
12177 }
12178
12179 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
12180 return Success(Value: E->getValue(), E);
12181 }
12182
12183 bool VisitOpenACCAsteriskSizeExpr(const OpenACCAsteriskSizeExpr *E) {
12184 // This should not be evaluated during constant expr evaluation, as it
12185 // should always be in an unevaluated context (the args list of a 'gang' or
12186 // 'tile' clause).
12187 return Error(E);
12188 }
12189
12190 bool VisitUnaryReal(const UnaryOperator *E);
12191 bool VisitUnaryImag(const UnaryOperator *E);
12192
12193 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
12194 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
12195 bool VisitSourceLocExpr(const SourceLocExpr *E);
12196 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
12197 bool VisitRequiresExpr(const RequiresExpr *E);
12198 // FIXME: Missing: array subscript of vector, member of vector
12199};
12200
12201class FixedPointExprEvaluator
12202 : public ExprEvaluatorBase<FixedPointExprEvaluator> {
12203 APValue &Result;
12204
12205 public:
12206 FixedPointExprEvaluator(EvalInfo &info, APValue &result)
12207 : ExprEvaluatorBaseTy(info), Result(result) {}
12208
12209 bool Success(const llvm::APInt &I, const Expr *E) {
12210 return Success(
12211 V: APFixedPoint(I, Info.Ctx.getFixedPointSemantics(Ty: E->getType())), E);
12212 }
12213
12214 bool Success(uint64_t Value, const Expr *E) {
12215 return Success(
12216 V: APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(Ty: E->getType())), E);
12217 }
12218
12219 bool Success(const APValue &V, const Expr *E) {
12220 return Success(V: V.getFixedPoint(), E);
12221 }
12222
12223 bool Success(const APFixedPoint &V, const Expr *E) {
12224 assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
12225 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&
12226 "Invalid evaluation result.");
12227 Result = APValue(V);
12228 return true;
12229 }
12230
12231 bool ZeroInitialization(const Expr *E) {
12232 return Success(Value: 0, E);
12233 }
12234
12235 //===--------------------------------------------------------------------===//
12236 // Visitor Methods
12237 //===--------------------------------------------------------------------===//
12238
12239 bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
12240 return Success(I: E->getValue(), E);
12241 }
12242
12243 bool VisitCastExpr(const CastExpr *E);
12244 bool VisitUnaryOperator(const UnaryOperator *E);
12245 bool VisitBinaryOperator(const BinaryOperator *E);
12246};
12247} // end anonymous namespace
12248
12249/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
12250/// produce either the integer value or a pointer.
12251///
12252/// GCC has a heinous extension which folds casts between pointer types and
12253/// pointer-sized integral types. We support this by allowing the evaluation of
12254/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
12255/// Some simple arithmetic on such values is supported (they are treated much
12256/// like char*).
12257static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
12258 EvalInfo &Info) {
12259 assert(!E->isValueDependent());
12260 assert(E->isPRValue() && E->getType()->isIntegralOrEnumerationType());
12261 return IntExprEvaluator(Info, Result).Visit(S: E);
12262}
12263
12264static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
12265 assert(!E->isValueDependent());
12266 APValue Val;
12267 if (!EvaluateIntegerOrLValue(E, Result&: Val, Info))
12268 return false;
12269 if (!Val.isInt()) {
12270 // FIXME: It would be better to produce the diagnostic for casting
12271 // a pointer to an integer.
12272 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
12273 return false;
12274 }
12275 Result = Val.getInt();
12276 return true;
12277}
12278
12279bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
12280 APValue Evaluated = E->EvaluateInContext(
12281 Ctx: Info.Ctx, DefaultExpr: Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
12282 return Success(V: Evaluated, E);
12283}
12284
12285static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
12286 EvalInfo &Info) {
12287 assert(!E->isValueDependent());
12288 if (E->getType()->isFixedPointType()) {
12289 APValue Val;
12290 if (!FixedPointExprEvaluator(Info, Val).Visit(S: E))
12291 return false;
12292 if (!Val.isFixedPoint())
12293 return false;
12294
12295 Result = Val.getFixedPoint();
12296 return true;
12297 }
12298 return false;
12299}
12300
12301static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
12302 EvalInfo &Info) {
12303 assert(!E->isValueDependent());
12304 if (E->getType()->isIntegerType()) {
12305 auto FXSema = Info.Ctx.getFixedPointSemantics(Ty: E->getType());
12306 APSInt Val;
12307 if (!EvaluateInteger(E, Result&: Val, Info))
12308 return false;
12309 Result = APFixedPoint(Val, FXSema);
12310 return true;
12311 } else if (E->getType()->isFixedPointType()) {
12312 return EvaluateFixedPoint(E, Result, Info);
12313 }
12314 return false;
12315}
12316
12317/// Check whether the given declaration can be directly converted to an integral
12318/// rvalue. If not, no diagnostic is produced; there are other things we can
12319/// try.
12320bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
12321 // Enums are integer constant exprs.
12322 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(Val: D)) {
12323 // Check for signedness/width mismatches between E type and ECD value.
12324 bool SameSign = (ECD->getInitVal().isSigned()
12325 == E->getType()->isSignedIntegerOrEnumerationType());
12326 bool SameWidth = (ECD->getInitVal().getBitWidth()
12327 == Info.Ctx.getIntWidth(T: E->getType()));
12328 if (SameSign && SameWidth)
12329 return Success(SI: ECD->getInitVal(), E);
12330 else {
12331 // Get rid of mismatch (otherwise Success assertions will fail)
12332 // by computing a new value matching the type of E.
12333 llvm::APSInt Val = ECD->getInitVal();
12334 if (!SameSign)
12335 Val.setIsSigned(!ECD->getInitVal().isSigned());
12336 if (!SameWidth)
12337 Val = Val.extOrTrunc(width: Info.Ctx.getIntWidth(T: E->getType()));
12338 return Success(SI: Val, E);
12339 }
12340 }
12341 return false;
12342}
12343
12344/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
12345/// as GCC.
12346GCCTypeClass EvaluateBuiltinClassifyType(QualType T,
12347 const LangOptions &LangOpts) {
12348 assert(!T->isDependentType() && "unexpected dependent type");
12349
12350 QualType CanTy = T.getCanonicalType();
12351
12352 switch (CanTy->getTypeClass()) {
12353#define TYPE(ID, BASE)
12354#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
12355#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
12356#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
12357#include "clang/AST/TypeNodes.inc"
12358 case Type::Auto:
12359 case Type::DeducedTemplateSpecialization:
12360 llvm_unreachable("unexpected non-canonical or dependent type");
12361
12362 case Type::Builtin:
12363 switch (cast<BuiltinType>(Val&: CanTy)->getKind()) {
12364#define BUILTIN_TYPE(ID, SINGLETON_ID)
12365#define SIGNED_TYPE(ID, SINGLETON_ID) \
12366 case BuiltinType::ID: return GCCTypeClass::Integer;
12367#define FLOATING_TYPE(ID, SINGLETON_ID) \
12368 case BuiltinType::ID: return GCCTypeClass::RealFloat;
12369#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
12370 case BuiltinType::ID: break;
12371#include "clang/AST/BuiltinTypes.def"
12372 case BuiltinType::Void:
12373 return GCCTypeClass::Void;
12374
12375 case BuiltinType::Bool:
12376 return GCCTypeClass::Bool;
12377
12378 case BuiltinType::Char_U:
12379 case BuiltinType::UChar:
12380 case BuiltinType::WChar_U:
12381 case BuiltinType::Char8:
12382 case BuiltinType::Char16:
12383 case BuiltinType::Char32:
12384 case BuiltinType::UShort:
12385 case BuiltinType::UInt:
12386 case BuiltinType::ULong:
12387 case BuiltinType::ULongLong:
12388 case BuiltinType::UInt128:
12389 return GCCTypeClass::Integer;
12390
12391 case BuiltinType::UShortAccum:
12392 case BuiltinType::UAccum:
12393 case BuiltinType::ULongAccum:
12394 case BuiltinType::UShortFract:
12395 case BuiltinType::UFract:
12396 case BuiltinType::ULongFract:
12397 case BuiltinType::SatUShortAccum:
12398 case BuiltinType::SatUAccum:
12399 case BuiltinType::SatULongAccum:
12400 case BuiltinType::SatUShortFract:
12401 case BuiltinType::SatUFract:
12402 case BuiltinType::SatULongFract:
12403 return GCCTypeClass::None;
12404
12405 case BuiltinType::NullPtr:
12406
12407 case BuiltinType::ObjCId:
12408 case BuiltinType::ObjCClass:
12409 case BuiltinType::ObjCSel:
12410#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
12411 case BuiltinType::Id:
12412#include "clang/Basic/OpenCLImageTypes.def"
12413#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
12414 case BuiltinType::Id:
12415#include "clang/Basic/OpenCLExtensionTypes.def"
12416 case BuiltinType::OCLSampler:
12417 case BuiltinType::OCLEvent:
12418 case BuiltinType::OCLClkEvent:
12419 case BuiltinType::OCLQueue:
12420 case BuiltinType::OCLReserveID:
12421#define SVE_TYPE(Name, Id, SingletonId) \
12422 case BuiltinType::Id:
12423#include "clang/Basic/AArch64ACLETypes.def"
12424#define PPC_VECTOR_TYPE(Name, Id, Size) \
12425 case BuiltinType::Id:
12426#include "clang/Basic/PPCTypes.def"
12427#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
12428#include "clang/Basic/RISCVVTypes.def"
12429#define WASM_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
12430#include "clang/Basic/WebAssemblyReferenceTypes.def"
12431#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align) case BuiltinType::Id:
12432#include "clang/Basic/AMDGPUTypes.def"
12433#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
12434#include "clang/Basic/HLSLIntangibleTypes.def"
12435 return GCCTypeClass::None;
12436
12437 case BuiltinType::Dependent:
12438 llvm_unreachable("unexpected dependent type");
12439 };
12440 llvm_unreachable("unexpected placeholder type");
12441
12442 case Type::Enum:
12443 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;
12444
12445 case Type::Pointer:
12446 case Type::ConstantArray:
12447 case Type::VariableArray:
12448 case Type::IncompleteArray:
12449 case Type::FunctionNoProto:
12450 case Type::FunctionProto:
12451 case Type::ArrayParameter:
12452 return GCCTypeClass::Pointer;
12453
12454 case Type::MemberPointer:
12455 return CanTy->isMemberDataPointerType()
12456 ? GCCTypeClass::PointerToDataMember
12457 : GCCTypeClass::PointerToMemberFunction;
12458
12459 case Type::Complex:
12460 return GCCTypeClass::Complex;
12461
12462 case Type::Record:
12463 return CanTy->isUnionType() ? GCCTypeClass::Union
12464 : GCCTypeClass::ClassOrStruct;
12465
12466 case Type::Atomic:
12467 // GCC classifies _Atomic T the same as T.
12468 return EvaluateBuiltinClassifyType(
12469 T: CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
12470
12471 case Type::Vector:
12472 case Type::ExtVector:
12473 return GCCTypeClass::Vector;
12474
12475 case Type::BlockPointer:
12476 case Type::ConstantMatrix:
12477 case Type::ObjCObject:
12478 case Type::ObjCInterface:
12479 case Type::ObjCObjectPointer:
12480 case Type::Pipe:
12481 case Type::HLSLAttributedResource:
12482 case Type::HLSLInlineSpirv:
12483 // Classify all other types that don't fit into the regular
12484 // classification the same way.
12485 return GCCTypeClass::None;
12486
12487 case Type::BitInt:
12488 return GCCTypeClass::BitInt;
12489
12490 case Type::LValueReference:
12491 case Type::RValueReference:
12492 llvm_unreachable("invalid type for expression");
12493 }
12494
12495 llvm_unreachable("unexpected type class");
12496}
12497
12498/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
12499/// as GCC.
12500static GCCTypeClass
12501EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
12502 // If no argument was supplied, default to None. This isn't
12503 // ideal, however it is what gcc does.
12504 if (E->getNumArgs() == 0)
12505 return GCCTypeClass::None;
12506
12507 // FIXME: Bizarrely, GCC treats a call with more than one argument as not
12508 // being an ICE, but still folds it to a constant using the type of the first
12509 // argument.
12510 return EvaluateBuiltinClassifyType(T: E->getArg(Arg: 0)->getType(), LangOpts);
12511}
12512
12513/// EvaluateBuiltinConstantPForLValue - Determine the result of
12514/// __builtin_constant_p when applied to the given pointer.
12515///
12516/// A pointer is only "constant" if it is null (or a pointer cast to integer)
12517/// or it points to the first character of a string literal.
12518static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
12519 APValue::LValueBase Base = LV.getLValueBase();
12520 if (Base.isNull()) {
12521 // A null base is acceptable.
12522 return true;
12523 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
12524 if (!isa<StringLiteral>(Val: E))
12525 return false;
12526 return LV.getLValueOffset().isZero();
12527 } else if (Base.is<TypeInfoLValue>()) {
12528 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
12529 // evaluate to true.
12530 return true;
12531 } else {
12532 // Any other base is not constant enough for GCC.
12533 return false;
12534 }
12535}
12536
12537/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
12538/// GCC as we can manage.
12539static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
12540 // This evaluation is not permitted to have side-effects, so evaluate it in
12541 // a speculative evaluation context.
12542 SpeculativeEvaluationRAII SpeculativeEval(Info);
12543
12544 // Constant-folding is always enabled for the operand of __builtin_constant_p
12545 // (even when the enclosing evaluation context otherwise requires a strict
12546 // language-specific constant expression).
12547 FoldConstant Fold(Info, true);
12548
12549 QualType ArgType = Arg->getType();
12550
12551 // __builtin_constant_p always has one operand. The rules which gcc follows
12552 // are not precisely documented, but are as follows:
12553 //
12554 // - If the operand is of integral, floating, complex or enumeration type,
12555 // and can be folded to a known value of that type, it returns 1.
12556 // - If the operand can be folded to a pointer to the first character
12557 // of a string literal (or such a pointer cast to an integral type)
12558 // or to a null pointer or an integer cast to a pointer, it returns 1.
12559 //
12560 // Otherwise, it returns 0.
12561 //
12562 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
12563 // its support for this did not work prior to GCC 9 and is not yet well
12564 // understood.
12565 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
12566 ArgType->isAnyComplexType() || ArgType->isPointerType() ||
12567 ArgType->isNullPtrType()) {
12568 APValue V;
12569 if (!::EvaluateAsRValue(Info, E: Arg, Result&: V) || Info.EvalStatus.HasSideEffects) {
12570 Fold.keepDiagnostics();
12571 return false;
12572 }
12573
12574 // For a pointer (possibly cast to integer), there are special rules.
12575 if (V.getKind() == APValue::LValue)
12576 return EvaluateBuiltinConstantPForLValue(LV: V);
12577
12578 // Otherwise, any constant value is good enough.
12579 return V.hasValue();
12580 }
12581
12582 // Anything else isn't considered to be sufficiently constant.
12583 return false;
12584}
12585
12586/// Retrieves the "underlying object type" of the given expression,
12587/// as used by __builtin_object_size.
12588static QualType getObjectType(APValue::LValueBase B) {
12589 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
12590 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
12591 return VD->getType();
12592 } else if (const Expr *E = B.dyn_cast<const Expr*>()) {
12593 if (isa<CompoundLiteralExpr>(Val: E))
12594 return E->getType();
12595 } else if (B.is<TypeInfoLValue>()) {
12596 return B.getTypeInfoType();
12597 } else if (B.is<DynamicAllocLValue>()) {
12598 return B.getDynamicAllocType();
12599 }
12600
12601 return QualType();
12602}
12603
12604/// A more selective version of E->IgnoreParenCasts for
12605/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
12606/// to change the type of E.
12607/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
12608///
12609/// Always returns an RValue with a pointer representation.
12610static const Expr *ignorePointerCastsAndParens(const Expr *E) {
12611 assert(E->isPRValue() && E->getType()->hasPointerRepresentation());
12612
12613 const Expr *NoParens = E->IgnoreParens();
12614 const auto *Cast = dyn_cast<CastExpr>(Val: NoParens);
12615 if (Cast == nullptr)
12616 return NoParens;
12617
12618 // We only conservatively allow a few kinds of casts, because this code is
12619 // inherently a simple solution that seeks to support the common case.
12620 auto CastKind = Cast->getCastKind();
12621 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
12622 CastKind != CK_AddressSpaceConversion)
12623 return NoParens;
12624
12625 const auto *SubExpr = Cast->getSubExpr();
12626 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isPRValue())
12627 return NoParens;
12628 return ignorePointerCastsAndParens(E: SubExpr);
12629}
12630
12631/// Checks to see if the given LValue's Designator is at the end of the LValue's
12632/// record layout. e.g.
12633/// struct { struct { int a, b; } fst, snd; } obj;
12634/// obj.fst // no
12635/// obj.snd // yes
12636/// obj.fst.a // no
12637/// obj.fst.b // no
12638/// obj.snd.a // no
12639/// obj.snd.b // yes
12640///
12641/// Please note: this function is specialized for how __builtin_object_size
12642/// views "objects".
12643///
12644/// If this encounters an invalid RecordDecl or otherwise cannot determine the
12645/// correct result, it will always return true.
12646static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
12647 assert(!LVal.Designator.Invalid);
12648
12649 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD) {
12650 const RecordDecl *Parent = FD->getParent();
12651 if (Parent->isInvalidDecl() || Parent->isUnion())
12652 return true;
12653 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(D: Parent);
12654 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
12655 };
12656
12657 auto &Base = LVal.getLValueBase();
12658 if (auto *ME = dyn_cast_or_null<MemberExpr>(Val: Base.dyn_cast<const Expr *>())) {
12659 if (auto *FD = dyn_cast<FieldDecl>(Val: ME->getMemberDecl())) {
12660 if (!IsLastOrInvalidFieldDecl(FD))
12661 return false;
12662 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(Val: ME->getMemberDecl())) {
12663 for (auto *FD : IFD->chain()) {
12664 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(Val: FD)))
12665 return false;
12666 }
12667 }
12668 }
12669
12670 unsigned I = 0;
12671 QualType BaseType = getType(B: Base);
12672 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
12673 // If we don't know the array bound, conservatively assume we're looking at
12674 // the final array element.
12675 ++I;
12676 if (BaseType->isIncompleteArrayType())
12677 BaseType = Ctx.getAsArrayType(T: BaseType)->getElementType();
12678 else
12679 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
12680 }
12681
12682 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
12683 const auto &Entry = LVal.Designator.Entries[I];
12684 if (BaseType->isArrayType()) {
12685 // Because __builtin_object_size treats arrays as objects, we can ignore
12686 // the index iff this is the last array in the Designator.
12687 if (I + 1 == E)
12688 return true;
12689 const auto *CAT = cast<ConstantArrayType>(Val: Ctx.getAsArrayType(T: BaseType));
12690 uint64_t Index = Entry.getAsArrayIndex();
12691 if (Index + 1 != CAT->getZExtSize())
12692 return false;
12693 BaseType = CAT->getElementType();
12694 } else if (BaseType->isAnyComplexType()) {
12695 const auto *CT = BaseType->castAs<ComplexType>();
12696 uint64_t Index = Entry.getAsArrayIndex();
12697 if (Index != 1)
12698 return false;
12699 BaseType = CT->getElementType();
12700 } else if (auto *FD = getAsField(E: Entry)) {
12701 if (!IsLastOrInvalidFieldDecl(FD))
12702 return false;
12703 BaseType = FD->getType();
12704 } else {
12705 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
12706 return false;
12707 }
12708 }
12709 return true;
12710}
12711
12712/// Tests to see if the LValue has a user-specified designator (that isn't
12713/// necessarily valid). Note that this always returns 'true' if the LValue has
12714/// an unsized array as its first designator entry, because there's currently no
12715/// way to tell if the user typed *foo or foo[0].
12716static bool refersToCompleteObject(const LValue &LVal) {
12717 if (LVal.Designator.Invalid)
12718 return false;
12719
12720 if (!LVal.Designator.Entries.empty())
12721 return LVal.Designator.isMostDerivedAnUnsizedArray();
12722
12723 if (!LVal.InvalidBase)
12724 return true;
12725
12726 // If `E` is a MemberExpr, then the first part of the designator is hiding in
12727 // the LValueBase.
12728 const auto *E = LVal.Base.dyn_cast<const Expr *>();
12729 return !E || !isa<MemberExpr>(Val: E);
12730}
12731
12732/// Attempts to detect a user writing into a piece of memory that's impossible
12733/// to figure out the size of by just using types.
12734static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
12735 const SubobjectDesignator &Designator = LVal.Designator;
12736 // Notes:
12737 // - Users can only write off of the end when we have an invalid base. Invalid
12738 // bases imply we don't know where the memory came from.
12739 // - We used to be a bit more aggressive here; we'd only be conservative if
12740 // the array at the end was flexible, or if it had 0 or 1 elements. This
12741 // broke some common standard library extensions (PR30346), but was
12742 // otherwise seemingly fine. It may be useful to reintroduce this behavior
12743 // with some sort of list. OTOH, it seems that GCC is always
12744 // conservative with the last element in structs (if it's an array), so our
12745 // current behavior is more compatible than an explicit list approach would
12746 // be.
12747 auto isFlexibleArrayMember = [&] {
12748 using FAMKind = LangOptions::StrictFlexArraysLevelKind;
12749 FAMKind StrictFlexArraysLevel =
12750 Ctx.getLangOpts().getStrictFlexArraysLevel();
12751
12752 if (Designator.isMostDerivedAnUnsizedArray())
12753 return true;
12754
12755 if (StrictFlexArraysLevel == FAMKind::Default)
12756 return true;
12757
12758 if (Designator.getMostDerivedArraySize() == 0 &&
12759 StrictFlexArraysLevel != FAMKind::IncompleteOnly)
12760 return true;
12761
12762 if (Designator.getMostDerivedArraySize() == 1 &&
12763 StrictFlexArraysLevel == FAMKind::OneZeroOrIncomplete)
12764 return true;
12765
12766 return false;
12767 };
12768
12769 return LVal.InvalidBase &&
12770 Designator.Entries.size() == Designator.MostDerivedPathLength &&
12771 Designator.MostDerivedIsArrayElement && isFlexibleArrayMember() &&
12772 isDesignatorAtObjectEnd(Ctx, LVal);
12773}
12774
12775/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
12776/// Fails if the conversion would cause loss of precision.
12777static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
12778 CharUnits &Result) {
12779 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
12780 if (Int.ugt(RHS: CharUnitsMax))
12781 return false;
12782 Result = CharUnits::fromQuantity(Quantity: Int.getZExtValue());
12783 return true;
12784}
12785
12786/// If we're evaluating the object size of an instance of a struct that
12787/// contains a flexible array member, add the size of the initializer.
12788static void addFlexibleArrayMemberInitSize(EvalInfo &Info, const QualType &T,
12789 const LValue &LV, CharUnits &Size) {
12790 if (!T.isNull() && T->isStructureType() &&
12791 T->getAsStructureType()->getDecl()->hasFlexibleArrayMember())
12792 if (const auto *V = LV.getLValueBase().dyn_cast<const ValueDecl *>())
12793 if (const auto *VD = dyn_cast<VarDecl>(Val: V))
12794 if (VD->hasInit())
12795 Size += VD->getFlexibleArrayInitChars(Ctx: Info.Ctx);
12796}
12797
12798/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
12799/// determine how many bytes exist from the beginning of the object to either
12800/// the end of the current subobject, or the end of the object itself, depending
12801/// on what the LValue looks like + the value of Type.
12802///
12803/// If this returns false, the value of Result is undefined.
12804static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
12805 unsigned Type, const LValue &LVal,
12806 CharUnits &EndOffset) {
12807 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
12808
12809 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
12810 if (Ty.isNull())
12811 return false;
12812
12813 Ty = Ty.getNonReferenceType();
12814
12815 if (Ty->isIncompleteType() || Ty->isFunctionType())
12816 return false;
12817
12818 return HandleSizeof(Info, Loc: ExprLoc, Type: Ty, Size&: Result);
12819 };
12820
12821 // We want to evaluate the size of the entire object. This is a valid fallback
12822 // for when Type=1 and the designator is invalid, because we're asked for an
12823 // upper-bound.
12824 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
12825 // Type=3 wants a lower bound, so we can't fall back to this.
12826 if (Type == 3 && !DetermineForCompleteObject)
12827 return false;
12828
12829 llvm::APInt APEndOffset;
12830 if (isBaseAnAllocSizeCall(Base: LVal.getLValueBase()) &&
12831 getBytesReturnedByAllocSizeCall(Ctx: Info.Ctx, LVal, Result&: APEndOffset))
12832 return convertUnsignedAPIntToCharUnits(Int: APEndOffset, Result&: EndOffset);
12833
12834 if (LVal.InvalidBase)
12835 return false;
12836
12837 QualType BaseTy = getObjectType(B: LVal.getLValueBase());
12838 const bool Ret = CheckedHandleSizeof(BaseTy, EndOffset);
12839 addFlexibleArrayMemberInitSize(Info, T: BaseTy, LV: LVal, Size&: EndOffset);
12840 return Ret;
12841 }
12842
12843 // We want to evaluate the size of a subobject.
12844 const SubobjectDesignator &Designator = LVal.Designator;
12845
12846 // The following is a moderately common idiom in C:
12847 //
12848 // struct Foo { int a; char c[1]; };
12849 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
12850 // strcpy(&F->c[0], Bar);
12851 //
12852 // In order to not break too much legacy code, we need to support it.
12853 if (isUserWritingOffTheEnd(Ctx: Info.Ctx, LVal)) {
12854 // If we can resolve this to an alloc_size call, we can hand that back,
12855 // because we know for certain how many bytes there are to write to.
12856 llvm::APInt APEndOffset;
12857 if (isBaseAnAllocSizeCall(Base: LVal.getLValueBase()) &&
12858 getBytesReturnedByAllocSizeCall(Ctx: Info.Ctx, LVal, Result&: APEndOffset))
12859 return convertUnsignedAPIntToCharUnits(Int: APEndOffset, Result&: EndOffset);
12860
12861 // If we cannot determine the size of the initial allocation, then we can't
12862 // given an accurate upper-bound. However, we are still able to give
12863 // conservative lower-bounds for Type=3.
12864 if (Type == 1)
12865 return false;
12866 }
12867
12868 CharUnits BytesPerElem;
12869 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
12870 return false;
12871
12872 // According to the GCC documentation, we want the size of the subobject
12873 // denoted by the pointer. But that's not quite right -- what we actually
12874 // want is the size of the immediately-enclosing array, if there is one.
12875 int64_t ElemsRemaining;
12876 if (Designator.MostDerivedIsArrayElement &&
12877 Designator.Entries.size() == Designator.MostDerivedPathLength) {
12878 uint64_t ArraySize = Designator.getMostDerivedArraySize();
12879 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
12880 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
12881 } else {
12882 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
12883 }
12884
12885 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
12886 return true;
12887}
12888
12889/// Tries to evaluate the __builtin_object_size for @p E. If successful,
12890/// returns true and stores the result in @p Size.
12891///
12892/// If @p WasError is non-null, this will report whether the failure to evaluate
12893/// is to be treated as an Error in IntExprEvaluator.
12894static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
12895 EvalInfo &Info, uint64_t &Size) {
12896 // Determine the denoted object.
12897 LValue LVal;
12898 {
12899 // The operand of __builtin_object_size is never evaluated for side-effects.
12900 // If there are any, but we can determine the pointed-to object anyway, then
12901 // ignore the side-effects.
12902 SpeculativeEvaluationRAII SpeculativeEval(Info);
12903 IgnoreSideEffectsRAII Fold(Info);
12904
12905 if (E->isGLValue()) {
12906 // It's possible for us to be given GLValues if we're called via
12907 // Expr::tryEvaluateObjectSize.
12908 APValue RVal;
12909 if (!EvaluateAsRValue(Info, E, Result&: RVal))
12910 return false;
12911 LVal.setFrom(Ctx&: Info.Ctx, V: RVal);
12912 } else if (!EvaluatePointer(E: ignorePointerCastsAndParens(E), Result&: LVal, Info,
12913 /*InvalidBaseOK=*/true))
12914 return false;
12915 }
12916
12917 // If we point to before the start of the object, there are no accessible
12918 // bytes.
12919 if (LVal.getLValueOffset().isNegative()) {
12920 Size = 0;
12921 return true;
12922 }
12923
12924 CharUnits EndOffset;
12925 if (!determineEndOffset(Info, ExprLoc: E->getExprLoc(), Type, LVal, EndOffset))
12926 return false;
12927
12928 // If we've fallen outside of the end offset, just pretend there's nothing to
12929 // write to/read from.
12930 if (EndOffset <= LVal.getLValueOffset())
12931 Size = 0;
12932 else
12933 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
12934 return true;
12935}
12936
12937bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
12938 if (!IsConstantEvaluatedBuiltinCall(E))
12939 return ExprEvaluatorBaseTy::VisitCallExpr(E);
12940 return VisitBuiltinCallExpr(E, BuiltinOp: E->getBuiltinCallee());
12941}
12942
12943static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
12944 APValue &Val, APSInt &Alignment) {
12945 QualType SrcTy = E->getArg(Arg: 0)->getType();
12946 if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: SrcTy, Info, Alignment))
12947 return false;
12948 // Even though we are evaluating integer expressions we could get a pointer
12949 // argument for the __builtin_is_aligned() case.
12950 if (SrcTy->isPointerType()) {
12951 LValue Ptr;
12952 if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: Ptr, Info))
12953 return false;
12954 Ptr.moveInto(V&: Val);
12955 } else if (!SrcTy->isIntegralOrEnumerationType()) {
12956 Info.FFDiag(E: E->getArg(Arg: 0));
12957 return false;
12958 } else {
12959 APSInt SrcInt;
12960 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: SrcInt, Info))
12961 return false;
12962 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&
12963 "Bit widths must be the same");
12964 Val = APValue(SrcInt);
12965 }
12966 assert(Val.hasValue());
12967 return true;
12968}
12969
12970bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
12971 unsigned BuiltinOp) {
12972 switch (BuiltinOp) {
12973 default:
12974 return false;
12975
12976 case Builtin::BI__builtin_dynamic_object_size:
12977 case Builtin::BI__builtin_object_size: {
12978 // The type was checked when we built the expression.
12979 unsigned Type =
12980 E->getArg(Arg: 1)->EvaluateKnownConstInt(Ctx: Info.Ctx).getZExtValue();
12981 assert(Type <= 3 && "unexpected type");
12982
12983 uint64_t Size;
12984 if (tryEvaluateBuiltinObjectSize(E: E->getArg(Arg: 0), Type, Info, Size))
12985 return Success(Value: Size, E);
12986
12987 if (E->getArg(Arg: 0)->HasSideEffects(Ctx: Info.Ctx))
12988 return Success(Value: (Type & 2) ? 0 : -1, E);
12989
12990 // Expression had no side effects, but we couldn't statically determine the
12991 // size of the referenced object.
12992 switch (Info.EvalMode) {
12993 case EvalInfo::EM_ConstantExpression:
12994 case EvalInfo::EM_ConstantFold:
12995 case EvalInfo::EM_IgnoreSideEffects:
12996 // Leave it to IR generation.
12997 return Error(E);
12998 case EvalInfo::EM_ConstantExpressionUnevaluated:
12999 // Reduce it to a constant now.
13000 return Success(Value: (Type & 2) ? 0 : -1, E);
13001 }
13002
13003 llvm_unreachable("unexpected EvalMode");
13004 }
13005
13006 case Builtin::BI__builtin_os_log_format_buffer_size: {
13007 analyze_os_log::OSLogBufferLayout Layout;
13008 analyze_os_log::computeOSLogBufferLayout(Ctx&: Info.Ctx, E, layout&: Layout);
13009 return Success(Value: Layout.size().getQuantity(), E);
13010 }
13011
13012 case Builtin::BI__builtin_is_aligned: {
13013 APValue Src;
13014 APSInt Alignment;
13015 if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
13016 return false;
13017 if (Src.isLValue()) {
13018 // If we evaluated a pointer, check the minimum known alignment.
13019 LValue Ptr;
13020 Ptr.setFrom(Ctx&: Info.Ctx, V: Src);
13021 CharUnits BaseAlignment = getBaseAlignment(Info, Value: Ptr);
13022 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(offset: Ptr.Offset);
13023 // We can return true if the known alignment at the computed offset is
13024 // greater than the requested alignment.
13025 assert(PtrAlign.isPowerOfTwo());
13026 assert(Alignment.isPowerOf2());
13027 if (PtrAlign.getQuantity() >= Alignment)
13028 return Success(Value: 1, E);
13029 // If the alignment is not known to be sufficient, some cases could still
13030 // be aligned at run time. However, if the requested alignment is less or
13031 // equal to the base alignment and the offset is not aligned, we know that
13032 // the run-time value can never be aligned.
13033 if (BaseAlignment.getQuantity() >= Alignment &&
13034 PtrAlign.getQuantity() < Alignment)
13035 return Success(Value: 0, E);
13036 // Otherwise we can't infer whether the value is sufficiently aligned.
13037 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
13038 // in cases where we can't fully evaluate the pointer.
13039 Info.FFDiag(E: E->getArg(Arg: 0), DiagId: diag::note_constexpr_alignment_compute)
13040 << Alignment;
13041 return false;
13042 }
13043 assert(Src.isInt());
13044 return Success(Value: (Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
13045 }
13046 case Builtin::BI__builtin_align_up: {
13047 APValue Src;
13048 APSInt Alignment;
13049 if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
13050 return false;
13051 if (!Src.isInt())
13052 return Error(E);
13053 APSInt AlignedVal =
13054 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
13055 Src.getInt().isUnsigned());
13056 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
13057 return Success(SI: AlignedVal, E);
13058 }
13059 case Builtin::BI__builtin_align_down: {
13060 APValue Src;
13061 APSInt Alignment;
13062 if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
13063 return false;
13064 if (!Src.isInt())
13065 return Error(E);
13066 APSInt AlignedVal =
13067 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
13068 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
13069 return Success(SI: AlignedVal, E);
13070 }
13071
13072 case Builtin::BI__builtin_bitreverse8:
13073 case Builtin::BI__builtin_bitreverse16:
13074 case Builtin::BI__builtin_bitreverse32:
13075 case Builtin::BI__builtin_bitreverse64:
13076 case Builtin::BI__builtin_elementwise_bitreverse: {
13077 APSInt Val;
13078 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13079 return false;
13080
13081 return Success(I: Val.reverseBits(), E);
13082 }
13083
13084 case Builtin::BI__builtin_bswap16:
13085 case Builtin::BI__builtin_bswap32:
13086 case Builtin::BI__builtin_bswap64: {
13087 APSInt Val;
13088 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13089 return false;
13090
13091 return Success(I: Val.byteSwap(), E);
13092 }
13093
13094 case Builtin::BI__builtin_classify_type:
13095 return Success(Value: (int)EvaluateBuiltinClassifyType(E, LangOpts: Info.getLangOpts()), E);
13096
13097 case Builtin::BI__builtin_clrsb:
13098 case Builtin::BI__builtin_clrsbl:
13099 case Builtin::BI__builtin_clrsbll: {
13100 APSInt Val;
13101 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13102 return false;
13103
13104 return Success(Value: Val.getBitWidth() - Val.getSignificantBits(), E);
13105 }
13106
13107 case Builtin::BI__builtin_clz:
13108 case Builtin::BI__builtin_clzl:
13109 case Builtin::BI__builtin_clzll:
13110 case Builtin::BI__builtin_clzs:
13111 case Builtin::BI__builtin_clzg:
13112 case Builtin::BI__lzcnt16: // Microsoft variants of count leading-zeroes
13113 case Builtin::BI__lzcnt:
13114 case Builtin::BI__lzcnt64: {
13115 APSInt Val;
13116 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13117 return false;
13118
13119 std::optional<APSInt> Fallback;
13120 if (BuiltinOp == Builtin::BI__builtin_clzg && E->getNumArgs() > 1) {
13121 APSInt FallbackTemp;
13122 if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: FallbackTemp, Info))
13123 return false;
13124 Fallback = FallbackTemp;
13125 }
13126
13127 if (!Val) {
13128 if (Fallback)
13129 return Success(SI: *Fallback, E);
13130
13131 // When the argument is 0, the result of GCC builtins is undefined,
13132 // whereas for Microsoft intrinsics, the result is the bit-width of the
13133 // argument.
13134 bool ZeroIsUndefined = BuiltinOp != Builtin::BI__lzcnt16 &&
13135 BuiltinOp != Builtin::BI__lzcnt &&
13136 BuiltinOp != Builtin::BI__lzcnt64;
13137
13138 if (ZeroIsUndefined)
13139 return Error(E);
13140 }
13141
13142 return Success(Value: Val.countl_zero(), E);
13143 }
13144
13145 case Builtin::BI__builtin_constant_p: {
13146 const Expr *Arg = E->getArg(Arg: 0);
13147 if (EvaluateBuiltinConstantP(Info, Arg))
13148 return Success(Value: true, E);
13149 if (Info.InConstantContext || Arg->HasSideEffects(Ctx: Info.Ctx)) {
13150 // Outside a constant context, eagerly evaluate to false in the presence
13151 // of side-effects in order to avoid -Wunsequenced false-positives in
13152 // a branch on __builtin_constant_p(expr).
13153 return Success(Value: false, E);
13154 }
13155 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
13156 return false;
13157 }
13158
13159 case Builtin::BI__noop:
13160 // __noop always evaluates successfully and returns 0.
13161 return Success(Value: 0, E);
13162
13163 case Builtin::BI__builtin_is_constant_evaluated: {
13164 const auto *Callee = Info.CurrentCall->getCallee();
13165 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
13166 (Info.CallStackDepth == 1 ||
13167 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
13168 Callee->getIdentifier() &&
13169 Callee->getIdentifier()->isStr(Str: "is_constant_evaluated")))) {
13170 // FIXME: Find a better way to avoid duplicated diagnostics.
13171 if (Info.EvalStatus.Diag)
13172 Info.report(Loc: (Info.CallStackDepth == 1)
13173 ? E->getExprLoc()
13174 : Info.CurrentCall->getCallRange().getBegin(),
13175 DiagId: diag::warn_is_constant_evaluated_always_true_constexpr)
13176 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
13177 : "std::is_constant_evaluated");
13178 }
13179
13180 return Success(Value: Info.InConstantContext, E);
13181 }
13182
13183 case Builtin::BI__builtin_is_within_lifetime:
13184 if (auto result = EvaluateBuiltinIsWithinLifetime(*this, E))
13185 return Success(Value: *result, E);
13186 return false;
13187
13188 case Builtin::BI__builtin_ctz:
13189 case Builtin::BI__builtin_ctzl:
13190 case Builtin::BI__builtin_ctzll:
13191 case Builtin::BI__builtin_ctzs:
13192 case Builtin::BI__builtin_ctzg: {
13193 APSInt Val;
13194 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13195 return false;
13196
13197 std::optional<APSInt> Fallback;
13198 if (BuiltinOp == Builtin::BI__builtin_ctzg && E->getNumArgs() > 1) {
13199 APSInt FallbackTemp;
13200 if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: FallbackTemp, Info))
13201 return false;
13202 Fallback = FallbackTemp;
13203 }
13204
13205 if (!Val) {
13206 if (Fallback)
13207 return Success(SI: *Fallback, E);
13208
13209 return Error(E);
13210 }
13211
13212 return Success(Value: Val.countr_zero(), E);
13213 }
13214
13215 case Builtin::BI__builtin_eh_return_data_regno: {
13216 int Operand = E->getArg(Arg: 0)->EvaluateKnownConstInt(Ctx: Info.Ctx).getZExtValue();
13217 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(RegNo: Operand);
13218 return Success(Value: Operand, E);
13219 }
13220
13221 case Builtin::BI__builtin_expect:
13222 case Builtin::BI__builtin_expect_with_probability:
13223 return Visit(S: E->getArg(Arg: 0));
13224
13225 case Builtin::BI__builtin_ptrauth_string_discriminator: {
13226 const auto *Literal =
13227 cast<StringLiteral>(Val: E->getArg(Arg: 0)->IgnoreParenImpCasts());
13228 uint64_t Result = getPointerAuthStableSipHash(S: Literal->getString());
13229 return Success(Value: Result, E);
13230 }
13231
13232 case Builtin::BI__builtin_ffs:
13233 case Builtin::BI__builtin_ffsl:
13234 case Builtin::BI__builtin_ffsll: {
13235 APSInt Val;
13236 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13237 return false;
13238
13239 unsigned N = Val.countr_zero();
13240 return Success(Value: N == Val.getBitWidth() ? 0 : N + 1, E);
13241 }
13242
13243 case Builtin::BI__builtin_fpclassify: {
13244 APFloat Val(0.0);
13245 if (!EvaluateFloat(E: E->getArg(Arg: 5), Result&: Val, Info))
13246 return false;
13247 unsigned Arg;
13248 switch (Val.getCategory()) {
13249 case APFloat::fcNaN: Arg = 0; break;
13250 case APFloat::fcInfinity: Arg = 1; break;
13251 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
13252 case APFloat::fcZero: Arg = 4; break;
13253 }
13254 return Visit(S: E->getArg(Arg));
13255 }
13256
13257 case Builtin::BI__builtin_isinf_sign: {
13258 APFloat Val(0.0);
13259 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13260 Success(Value: Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
13261 }
13262
13263 case Builtin::BI__builtin_isinf: {
13264 APFloat Val(0.0);
13265 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13266 Success(Value: Val.isInfinity() ? 1 : 0, E);
13267 }
13268
13269 case Builtin::BI__builtin_isfinite: {
13270 APFloat Val(0.0);
13271 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13272 Success(Value: Val.isFinite() ? 1 : 0, E);
13273 }
13274
13275 case Builtin::BI__builtin_isnan: {
13276 APFloat Val(0.0);
13277 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13278 Success(Value: Val.isNaN() ? 1 : 0, E);
13279 }
13280
13281 case Builtin::BI__builtin_isnormal: {
13282 APFloat Val(0.0);
13283 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13284 Success(Value: Val.isNormal() ? 1 : 0, E);
13285 }
13286
13287 case Builtin::BI__builtin_issubnormal: {
13288 APFloat Val(0.0);
13289 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13290 Success(Value: Val.isDenormal() ? 1 : 0, E);
13291 }
13292
13293 case Builtin::BI__builtin_iszero: {
13294 APFloat Val(0.0);
13295 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13296 Success(Value: Val.isZero() ? 1 : 0, E);
13297 }
13298
13299 case Builtin::BI__builtin_signbit:
13300 case Builtin::BI__builtin_signbitf:
13301 case Builtin::BI__builtin_signbitl: {
13302 APFloat Val(0.0);
13303 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13304 Success(Value: Val.isNegative() ? 1 : 0, E);
13305 }
13306
13307 case Builtin::BI__builtin_isgreater:
13308 case Builtin::BI__builtin_isgreaterequal:
13309 case Builtin::BI__builtin_isless:
13310 case Builtin::BI__builtin_islessequal:
13311 case Builtin::BI__builtin_islessgreater:
13312 case Builtin::BI__builtin_isunordered: {
13313 APFloat LHS(0.0);
13314 APFloat RHS(0.0);
13315 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
13316 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
13317 return false;
13318
13319 return Success(
13320 Value: [&] {
13321 switch (BuiltinOp) {
13322 case Builtin::BI__builtin_isgreater:
13323 return LHS > RHS;
13324 case Builtin::BI__builtin_isgreaterequal:
13325 return LHS >= RHS;
13326 case Builtin::BI__builtin_isless:
13327 return LHS < RHS;
13328 case Builtin::BI__builtin_islessequal:
13329 return LHS <= RHS;
13330 case Builtin::BI__builtin_islessgreater: {
13331 APFloat::cmpResult cmp = LHS.compare(RHS);
13332 return cmp == APFloat::cmpResult::cmpLessThan ||
13333 cmp == APFloat::cmpResult::cmpGreaterThan;
13334 }
13335 case Builtin::BI__builtin_isunordered:
13336 return LHS.compare(RHS) == APFloat::cmpResult::cmpUnordered;
13337 default:
13338 llvm_unreachable("Unexpected builtin ID: Should be a floating "
13339 "point comparison function");
13340 }
13341 }()
13342 ? 1
13343 : 0,
13344 E);
13345 }
13346
13347 case Builtin::BI__builtin_issignaling: {
13348 APFloat Val(0.0);
13349 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13350 Success(Value: Val.isSignaling() ? 1 : 0, E);
13351 }
13352
13353 case Builtin::BI__builtin_isfpclass: {
13354 APSInt MaskVal;
13355 if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: MaskVal, Info))
13356 return false;
13357 unsigned Test = static_cast<llvm::FPClassTest>(MaskVal.getZExtValue());
13358 APFloat Val(0.0);
13359 return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
13360 Success(Value: (Val.classify() & Test) ? 1 : 0, E);
13361 }
13362
13363 case Builtin::BI__builtin_parity:
13364 case Builtin::BI__builtin_parityl:
13365 case Builtin::BI__builtin_parityll: {
13366 APSInt Val;
13367 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13368 return false;
13369
13370 return Success(Value: Val.popcount() % 2, E);
13371 }
13372
13373 case Builtin::BI__builtin_abs:
13374 case Builtin::BI__builtin_labs:
13375 case Builtin::BI__builtin_llabs: {
13376 APSInt Val;
13377 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13378 return false;
13379 if (Val == APSInt(APInt::getSignedMinValue(numBits: Val.getBitWidth()),
13380 /*IsUnsigned=*/false))
13381 return false;
13382 if (Val.isNegative())
13383 Val.negate();
13384 return Success(SI: Val, E);
13385 }
13386
13387 case Builtin::BI__builtin_popcount:
13388 case Builtin::BI__builtin_popcountl:
13389 case Builtin::BI__builtin_popcountll:
13390 case Builtin::BI__builtin_popcountg:
13391 case Builtin::BI__builtin_elementwise_popcount:
13392 case Builtin::BI__popcnt16: // Microsoft variants of popcount
13393 case Builtin::BI__popcnt:
13394 case Builtin::BI__popcnt64: {
13395 APSInt Val;
13396 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13397 return false;
13398
13399 return Success(Value: Val.popcount(), E);
13400 }
13401
13402 case Builtin::BI__builtin_rotateleft8:
13403 case Builtin::BI__builtin_rotateleft16:
13404 case Builtin::BI__builtin_rotateleft32:
13405 case Builtin::BI__builtin_rotateleft64:
13406 case Builtin::BI_rotl8: // Microsoft variants of rotate right
13407 case Builtin::BI_rotl16:
13408 case Builtin::BI_rotl:
13409 case Builtin::BI_lrotl:
13410 case Builtin::BI_rotl64: {
13411 APSInt Val, Amt;
13412 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13413 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Amt, Info))
13414 return false;
13415
13416 return Success(I: Val.rotl(rotateAmt: Amt.urem(RHS: Val.getBitWidth())), E);
13417 }
13418
13419 case Builtin::BI__builtin_rotateright8:
13420 case Builtin::BI__builtin_rotateright16:
13421 case Builtin::BI__builtin_rotateright32:
13422 case Builtin::BI__builtin_rotateright64:
13423 case Builtin::BI_rotr8: // Microsoft variants of rotate right
13424 case Builtin::BI_rotr16:
13425 case Builtin::BI_rotr:
13426 case Builtin::BI_lrotr:
13427 case Builtin::BI_rotr64: {
13428 APSInt Val, Amt;
13429 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13430 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Amt, Info))
13431 return false;
13432
13433 return Success(I: Val.rotr(rotateAmt: Amt.urem(RHS: Val.getBitWidth())), E);
13434 }
13435
13436 case Builtin::BI__builtin_elementwise_add_sat: {
13437 APSInt LHS, RHS;
13438 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
13439 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info))
13440 return false;
13441
13442 APInt Result = LHS.isSigned() ? LHS.sadd_sat(RHS) : LHS.uadd_sat(RHS);
13443 return Success(SI: APSInt(Result, !LHS.isSigned()), E);
13444 }
13445 case Builtin::BI__builtin_elementwise_sub_sat: {
13446 APSInt LHS, RHS;
13447 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
13448 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info))
13449 return false;
13450
13451 APInt Result = LHS.isSigned() ? LHS.ssub_sat(RHS) : LHS.usub_sat(RHS);
13452 return Success(SI: APSInt(Result, !LHS.isSigned()), E);
13453 }
13454
13455 case Builtin::BIstrlen:
13456 case Builtin::BIwcslen:
13457 // A call to strlen is not a constant expression.
13458 if (Info.getLangOpts().CPlusPlus11)
13459 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_function)
13460 << /*isConstexpr*/ 0 << /*isConstructor*/ 0
13461 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp);
13462 else
13463 Info.CCEDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
13464 [[fallthrough]];
13465 case Builtin::BI__builtin_strlen:
13466 case Builtin::BI__builtin_wcslen: {
13467 // As an extension, we support __builtin_strlen() as a constant expression,
13468 // and support folding strlen() to a constant.
13469 uint64_t StrLen;
13470 if (EvaluateBuiltinStrLen(E: E->getArg(Arg: 0), Result&: StrLen, Info))
13471 return Success(Value: StrLen, E);
13472 return false;
13473 }
13474
13475 case Builtin::BIstrcmp:
13476 case Builtin::BIwcscmp:
13477 case Builtin::BIstrncmp:
13478 case Builtin::BIwcsncmp:
13479 case Builtin::BImemcmp:
13480 case Builtin::BIbcmp:
13481 case Builtin::BIwmemcmp:
13482 // A call to strlen is not a constant expression.
13483 if (Info.getLangOpts().CPlusPlus11)
13484 Info.CCEDiag(E, DiagId: diag::note_constexpr_invalid_function)
13485 << /*isConstexpr*/ 0 << /*isConstructor*/ 0
13486 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp);
13487 else
13488 Info.CCEDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
13489 [[fallthrough]];
13490 case Builtin::BI__builtin_strcmp:
13491 case Builtin::BI__builtin_wcscmp:
13492 case Builtin::BI__builtin_strncmp:
13493 case Builtin::BI__builtin_wcsncmp:
13494 case Builtin::BI__builtin_memcmp:
13495 case Builtin::BI__builtin_bcmp:
13496 case Builtin::BI__builtin_wmemcmp: {
13497 LValue String1, String2;
13498 if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: String1, Info) ||
13499 !EvaluatePointer(E: E->getArg(Arg: 1), Result&: String2, Info))
13500 return false;
13501
13502 uint64_t MaxLength = uint64_t(-1);
13503 if (BuiltinOp != Builtin::BIstrcmp &&
13504 BuiltinOp != Builtin::BIwcscmp &&
13505 BuiltinOp != Builtin::BI__builtin_strcmp &&
13506 BuiltinOp != Builtin::BI__builtin_wcscmp) {
13507 APSInt N;
13508 if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
13509 return false;
13510 MaxLength = N.getZExtValue();
13511 }
13512
13513 // Empty substrings compare equal by definition.
13514 if (MaxLength == 0u)
13515 return Success(Value: 0, E);
13516
13517 if (!String1.checkNullPointerForFoldAccess(Info, E, AK: AK_Read) ||
13518 !String2.checkNullPointerForFoldAccess(Info, E, AK: AK_Read) ||
13519 String1.Designator.Invalid || String2.Designator.Invalid)
13520 return false;
13521
13522 QualType CharTy1 = String1.Designator.getType(Ctx&: Info.Ctx);
13523 QualType CharTy2 = String2.Designator.getType(Ctx&: Info.Ctx);
13524
13525 bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
13526 BuiltinOp == Builtin::BIbcmp ||
13527 BuiltinOp == Builtin::BI__builtin_memcmp ||
13528 BuiltinOp == Builtin::BI__builtin_bcmp;
13529
13530 assert(IsRawByte ||
13531 (Info.Ctx.hasSameUnqualifiedType(
13532 CharTy1, E->getArg(0)->getType()->getPointeeType()) &&
13533 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)));
13534
13535 // For memcmp, allow comparing any arrays of '[[un]signed] char' or
13536 // 'char8_t', but no other types.
13537 if (IsRawByte &&
13538 !(isOneByteCharacterType(T: CharTy1) && isOneByteCharacterType(T: CharTy2))) {
13539 // FIXME: Consider using our bit_cast implementation to support this.
13540 Info.FFDiag(E, DiagId: diag::note_constexpr_memcmp_unsupported)
13541 << Info.Ctx.BuiltinInfo.getQuotedName(ID: BuiltinOp) << CharTy1
13542 << CharTy2;
13543 return false;
13544 }
13545
13546 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
13547 return handleLValueToRValueConversion(Info, Conv: E, Type: CharTy1, LVal: String1, RVal&: Char1) &&
13548 handleLValueToRValueConversion(Info, Conv: E, Type: CharTy2, LVal: String2, RVal&: Char2) &&
13549 Char1.isInt() && Char2.isInt();
13550 };
13551 const auto &AdvanceElems = [&] {
13552 return HandleLValueArrayAdjustment(Info, E, LVal&: String1, EltTy: CharTy1, Adjustment: 1) &&
13553 HandleLValueArrayAdjustment(Info, E, LVal&: String2, EltTy: CharTy2, Adjustment: 1);
13554 };
13555
13556 bool StopAtNull =
13557 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
13558 BuiltinOp != Builtin::BIwmemcmp &&
13559 BuiltinOp != Builtin::BI__builtin_memcmp &&
13560 BuiltinOp != Builtin::BI__builtin_bcmp &&
13561 BuiltinOp != Builtin::BI__builtin_wmemcmp);
13562 bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
13563 BuiltinOp == Builtin::BIwcsncmp ||
13564 BuiltinOp == Builtin::BIwmemcmp ||
13565 BuiltinOp == Builtin::BI__builtin_wcscmp ||
13566 BuiltinOp == Builtin::BI__builtin_wcsncmp ||
13567 BuiltinOp == Builtin::BI__builtin_wmemcmp;
13568
13569 for (; MaxLength; --MaxLength) {
13570 APValue Char1, Char2;
13571 if (!ReadCurElems(Char1, Char2))
13572 return false;
13573 if (Char1.getInt().ne(RHS: Char2.getInt())) {
13574 if (IsWide) // wmemcmp compares with wchar_t signedness.
13575 return Success(Value: Char1.getInt() < Char2.getInt() ? -1 : 1, E);
13576 // memcmp always compares unsigned chars.
13577 return Success(Value: Char1.getInt().ult(RHS: Char2.getInt()) ? -1 : 1, E);
13578 }
13579 if (StopAtNull && !Char1.getInt())
13580 return Success(Value: 0, E);
13581 assert(!(StopAtNull && !Char2.getInt()));
13582 if (!AdvanceElems())
13583 return false;
13584 }
13585 // We hit the strncmp / memcmp limit.
13586 return Success(Value: 0, E);
13587 }
13588
13589 case Builtin::BI__atomic_always_lock_free:
13590 case Builtin::BI__atomic_is_lock_free:
13591 case Builtin::BI__c11_atomic_is_lock_free: {
13592 APSInt SizeVal;
13593 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: SizeVal, Info))
13594 return false;
13595
13596 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
13597 // of two less than or equal to the maximum inline atomic width, we know it
13598 // is lock-free. If the size isn't a power of two, or greater than the
13599 // maximum alignment where we promote atomics, we know it is not lock-free
13600 // (at least not in the sense of atomic_is_lock_free). Otherwise,
13601 // the answer can only be determined at runtime; for example, 16-byte
13602 // atomics have lock-free implementations on some, but not all,
13603 // x86-64 processors.
13604
13605 // Check power-of-two.
13606 CharUnits Size = CharUnits::fromQuantity(Quantity: SizeVal.getZExtValue());
13607 if (Size.isPowerOfTwo()) {
13608 // Check against inlining width.
13609 unsigned InlineWidthBits =
13610 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
13611 if (Size <= Info.Ctx.toCharUnitsFromBits(BitSize: InlineWidthBits)) {
13612 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
13613 Size == CharUnits::One())
13614 return Success(Value: 1, E);
13615
13616 // If the pointer argument can be evaluated to a compile-time constant
13617 // integer (or nullptr), check if that value is appropriately aligned.
13618 const Expr *PtrArg = E->getArg(Arg: 1);
13619 Expr::EvalResult ExprResult;
13620 APSInt IntResult;
13621 if (PtrArg->EvaluateAsRValue(Result&: ExprResult, Ctx: Info.Ctx) &&
13622 ExprResult.Val.toIntegralConstant(Result&: IntResult, SrcTy: PtrArg->getType(),
13623 Ctx: Info.Ctx) &&
13624 IntResult.isAligned(A: Size.getAsAlign()))
13625 return Success(Value: 1, E);
13626
13627 // Otherwise, check if the type's alignment against Size.
13628 if (auto *ICE = dyn_cast<ImplicitCastExpr>(Val: PtrArg)) {
13629 // Drop the potential implicit-cast to 'const volatile void*', getting
13630 // the underlying type.
13631 if (ICE->getCastKind() == CK_BitCast)
13632 PtrArg = ICE->getSubExpr();
13633 }
13634
13635 if (auto PtrTy = PtrArg->getType()->getAs<PointerType>()) {
13636 QualType PointeeType = PtrTy->getPointeeType();
13637 if (!PointeeType->isIncompleteType() &&
13638 Info.Ctx.getTypeAlignInChars(T: PointeeType) >= Size) {
13639 // OK, we will inline operations on this object.
13640 return Success(Value: 1, E);
13641 }
13642 }
13643 }
13644 }
13645
13646 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
13647 Success(Value: 0, E) : Error(E);
13648 }
13649 case Builtin::BI__builtin_addcb:
13650 case Builtin::BI__builtin_addcs:
13651 case Builtin::BI__builtin_addc:
13652 case Builtin::BI__builtin_addcl:
13653 case Builtin::BI__builtin_addcll:
13654 case Builtin::BI__builtin_subcb:
13655 case Builtin::BI__builtin_subcs:
13656 case Builtin::BI__builtin_subc:
13657 case Builtin::BI__builtin_subcl:
13658 case Builtin::BI__builtin_subcll: {
13659 LValue CarryOutLValue;
13660 APSInt LHS, RHS, CarryIn, CarryOut, Result;
13661 QualType ResultType = E->getArg(Arg: 0)->getType();
13662 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
13663 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info) ||
13664 !EvaluateInteger(E: E->getArg(Arg: 2), Result&: CarryIn, Info) ||
13665 !EvaluatePointer(E: E->getArg(Arg: 3), Result&: CarryOutLValue, Info))
13666 return false;
13667 // Copy the number of bits and sign.
13668 Result = LHS;
13669 CarryOut = LHS;
13670
13671 bool FirstOverflowed = false;
13672 bool SecondOverflowed = false;
13673 switch (BuiltinOp) {
13674 default:
13675 llvm_unreachable("Invalid value for BuiltinOp");
13676 case Builtin::BI__builtin_addcb:
13677 case Builtin::BI__builtin_addcs:
13678 case Builtin::BI__builtin_addc:
13679 case Builtin::BI__builtin_addcl:
13680 case Builtin::BI__builtin_addcll:
13681 Result =
13682 LHS.uadd_ov(RHS, Overflow&: FirstOverflowed).uadd_ov(RHS: CarryIn, Overflow&: SecondOverflowed);
13683 break;
13684 case Builtin::BI__builtin_subcb:
13685 case Builtin::BI__builtin_subcs:
13686 case Builtin::BI__builtin_subc:
13687 case Builtin::BI__builtin_subcl:
13688 case Builtin::BI__builtin_subcll:
13689 Result =
13690 LHS.usub_ov(RHS, Overflow&: FirstOverflowed).usub_ov(RHS: CarryIn, Overflow&: SecondOverflowed);
13691 break;
13692 }
13693
13694 // It is possible for both overflows to happen but CGBuiltin uses an OR so
13695 // this is consistent.
13696 CarryOut = (uint64_t)(FirstOverflowed | SecondOverflowed);
13697 APValue APV{CarryOut};
13698 if (!handleAssignment(Info, E, LVal: CarryOutLValue, LValType: ResultType, Val&: APV))
13699 return false;
13700 return Success(SI: Result, E);
13701 }
13702 case Builtin::BI__builtin_add_overflow:
13703 case Builtin::BI__builtin_sub_overflow:
13704 case Builtin::BI__builtin_mul_overflow:
13705 case Builtin::BI__builtin_sadd_overflow:
13706 case Builtin::BI__builtin_uadd_overflow:
13707 case Builtin::BI__builtin_uaddl_overflow:
13708 case Builtin::BI__builtin_uaddll_overflow:
13709 case Builtin::BI__builtin_usub_overflow:
13710 case Builtin::BI__builtin_usubl_overflow:
13711 case Builtin::BI__builtin_usubll_overflow:
13712 case Builtin::BI__builtin_umul_overflow:
13713 case Builtin::BI__builtin_umull_overflow:
13714 case Builtin::BI__builtin_umulll_overflow:
13715 case Builtin::BI__builtin_saddl_overflow:
13716 case Builtin::BI__builtin_saddll_overflow:
13717 case Builtin::BI__builtin_ssub_overflow:
13718 case Builtin::BI__builtin_ssubl_overflow:
13719 case Builtin::BI__builtin_ssubll_overflow:
13720 case Builtin::BI__builtin_smul_overflow:
13721 case Builtin::BI__builtin_smull_overflow:
13722 case Builtin::BI__builtin_smulll_overflow: {
13723 LValue ResultLValue;
13724 APSInt LHS, RHS;
13725
13726 QualType ResultType = E->getArg(Arg: 2)->getType()->getPointeeType();
13727 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
13728 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info) ||
13729 !EvaluatePointer(E: E->getArg(Arg: 2), Result&: ResultLValue, Info))
13730 return false;
13731
13732 APSInt Result;
13733 bool DidOverflow = false;
13734
13735 // If the types don't have to match, enlarge all 3 to the largest of them.
13736 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
13737 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
13738 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
13739 bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
13740 ResultType->isSignedIntegerOrEnumerationType();
13741 bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
13742 ResultType->isSignedIntegerOrEnumerationType();
13743 uint64_t LHSSize = LHS.getBitWidth();
13744 uint64_t RHSSize = RHS.getBitWidth();
13745 uint64_t ResultSize = Info.Ctx.getTypeSize(T: ResultType);
13746 uint64_t MaxBits = std::max(a: std::max(a: LHSSize, b: RHSSize), b: ResultSize);
13747
13748 // Add an additional bit if the signedness isn't uniformly agreed to. We
13749 // could do this ONLY if there is a signed and an unsigned that both have
13750 // MaxBits, but the code to check that is pretty nasty. The issue will be
13751 // caught in the shrink-to-result later anyway.
13752 if (IsSigned && !AllSigned)
13753 ++MaxBits;
13754
13755 LHS = APSInt(LHS.extOrTrunc(width: MaxBits), !IsSigned);
13756 RHS = APSInt(RHS.extOrTrunc(width: MaxBits), !IsSigned);
13757 Result = APSInt(MaxBits, !IsSigned);
13758 }
13759
13760 // Find largest int.
13761 switch (BuiltinOp) {
13762 default:
13763 llvm_unreachable("Invalid value for BuiltinOp");
13764 case Builtin::BI__builtin_add_overflow:
13765 case Builtin::BI__builtin_sadd_overflow:
13766 case Builtin::BI__builtin_saddl_overflow:
13767 case Builtin::BI__builtin_saddll_overflow:
13768 case Builtin::BI__builtin_uadd_overflow:
13769 case Builtin::BI__builtin_uaddl_overflow:
13770 case Builtin::BI__builtin_uaddll_overflow:
13771 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, Overflow&: DidOverflow)
13772 : LHS.uadd_ov(RHS, Overflow&: DidOverflow);
13773 break;
13774 case Builtin::BI__builtin_sub_overflow:
13775 case Builtin::BI__builtin_ssub_overflow:
13776 case Builtin::BI__builtin_ssubl_overflow:
13777 case Builtin::BI__builtin_ssubll_overflow:
13778 case Builtin::BI__builtin_usub_overflow:
13779 case Builtin::BI__builtin_usubl_overflow:
13780 case Builtin::BI__builtin_usubll_overflow:
13781 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, Overflow&: DidOverflow)
13782 : LHS.usub_ov(RHS, Overflow&: DidOverflow);
13783 break;
13784 case Builtin::BI__builtin_mul_overflow:
13785 case Builtin::BI__builtin_smul_overflow:
13786 case Builtin::BI__builtin_smull_overflow:
13787 case Builtin::BI__builtin_smulll_overflow:
13788 case Builtin::BI__builtin_umul_overflow:
13789 case Builtin::BI__builtin_umull_overflow:
13790 case Builtin::BI__builtin_umulll_overflow:
13791 Result = LHS.isSigned() ? LHS.smul_ov(RHS, Overflow&: DidOverflow)
13792 : LHS.umul_ov(RHS, Overflow&: DidOverflow);
13793 break;
13794 }
13795
13796 // In the case where multiple sizes are allowed, truncate and see if
13797 // the values are the same.
13798 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
13799 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
13800 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
13801 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
13802 // since it will give us the behavior of a TruncOrSelf in the case where
13803 // its parameter <= its size. We previously set Result to be at least the
13804 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
13805 // will work exactly like TruncOrSelf.
13806 APSInt Temp = Result.extOrTrunc(width: Info.Ctx.getTypeSize(T: ResultType));
13807 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());
13808
13809 if (!APSInt::isSameValue(I1: Temp, I2: Result))
13810 DidOverflow = true;
13811 Result = Temp;
13812 }
13813
13814 APValue APV{Result};
13815 if (!handleAssignment(Info, E, LVal: ResultLValue, LValType: ResultType, Val&: APV))
13816 return false;
13817 return Success(Value: DidOverflow, E);
13818 }
13819
13820 case Builtin::BI__builtin_reduce_add:
13821 case Builtin::BI__builtin_reduce_mul:
13822 case Builtin::BI__builtin_reduce_and:
13823 case Builtin::BI__builtin_reduce_or:
13824 case Builtin::BI__builtin_reduce_xor:
13825 case Builtin::BI__builtin_reduce_min:
13826 case Builtin::BI__builtin_reduce_max: {
13827 APValue Source;
13828 if (!EvaluateAsRValue(Info, E: E->getArg(Arg: 0), Result&: Source))
13829 return false;
13830
13831 unsigned SourceLen = Source.getVectorLength();
13832 APSInt Reduced = Source.getVectorElt(I: 0).getInt();
13833 for (unsigned EltNum = 1; EltNum < SourceLen; ++EltNum) {
13834 switch (BuiltinOp) {
13835 default:
13836 return false;
13837 case Builtin::BI__builtin_reduce_add: {
13838 if (!CheckedIntArithmetic(
13839 Info, E, LHS: Reduced, RHS: Source.getVectorElt(I: EltNum).getInt(),
13840 BitWidth: Reduced.getBitWidth() + 1, Op: std::plus<APSInt>(), Result&: Reduced))
13841 return false;
13842 break;
13843 }
13844 case Builtin::BI__builtin_reduce_mul: {
13845 if (!CheckedIntArithmetic(
13846 Info, E, LHS: Reduced, RHS: Source.getVectorElt(I: EltNum).getInt(),
13847 BitWidth: Reduced.getBitWidth() * 2, Op: std::multiplies<APSInt>(), Result&: Reduced))
13848 return false;
13849 break;
13850 }
13851 case Builtin::BI__builtin_reduce_and: {
13852 Reduced &= Source.getVectorElt(I: EltNum).getInt();
13853 break;
13854 }
13855 case Builtin::BI__builtin_reduce_or: {
13856 Reduced |= Source.getVectorElt(I: EltNum).getInt();
13857 break;
13858 }
13859 case Builtin::BI__builtin_reduce_xor: {
13860 Reduced ^= Source.getVectorElt(I: EltNum).getInt();
13861 break;
13862 }
13863 case Builtin::BI__builtin_reduce_min: {
13864 Reduced = std::min(a: Reduced, b: Source.getVectorElt(I: EltNum).getInt());
13865 break;
13866 }
13867 case Builtin::BI__builtin_reduce_max: {
13868 Reduced = std::max(a: Reduced, b: Source.getVectorElt(I: EltNum).getInt());
13869 break;
13870 }
13871 }
13872 }
13873
13874 return Success(SI: Reduced, E);
13875 }
13876
13877 case clang::X86::BI__builtin_ia32_addcarryx_u32:
13878 case clang::X86::BI__builtin_ia32_addcarryx_u64:
13879 case clang::X86::BI__builtin_ia32_subborrow_u32:
13880 case clang::X86::BI__builtin_ia32_subborrow_u64: {
13881 LValue ResultLValue;
13882 APSInt CarryIn, LHS, RHS;
13883 QualType ResultType = E->getArg(Arg: 3)->getType()->getPointeeType();
13884 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: CarryIn, Info) ||
13885 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: LHS, Info) ||
13886 !EvaluateInteger(E: E->getArg(Arg: 2), Result&: RHS, Info) ||
13887 !EvaluatePointer(E: E->getArg(Arg: 3), Result&: ResultLValue, Info))
13888 return false;
13889
13890 bool IsAdd = BuiltinOp == clang::X86::BI__builtin_ia32_addcarryx_u32 ||
13891 BuiltinOp == clang::X86::BI__builtin_ia32_addcarryx_u64;
13892
13893 unsigned BitWidth = LHS.getBitWidth();
13894 unsigned CarryInBit = CarryIn.ugt(RHS: 0) ? 1 : 0;
13895 APInt ExResult =
13896 IsAdd
13897 ? (LHS.zext(width: BitWidth + 1) + (RHS.zext(width: BitWidth + 1) + CarryInBit))
13898 : (LHS.zext(width: BitWidth + 1) - (RHS.zext(width: BitWidth + 1) + CarryInBit));
13899
13900 APInt Result = ExResult.extractBits(numBits: BitWidth, bitPosition: 0);
13901 uint64_t CarryOut = ExResult.extractBitsAsZExtValue(numBits: 1, bitPosition: BitWidth);
13902
13903 APValue APV{APSInt(Result, /*isUnsigned=*/true)};
13904 if (!handleAssignment(Info, E, LVal: ResultLValue, LValType: ResultType, Val&: APV))
13905 return false;
13906 return Success(Value: CarryOut, E);
13907 }
13908
13909 case clang::X86::BI__builtin_ia32_bextr_u32:
13910 case clang::X86::BI__builtin_ia32_bextr_u64:
13911 case clang::X86::BI__builtin_ia32_bextri_u32:
13912 case clang::X86::BI__builtin_ia32_bextri_u64: {
13913 APSInt Val, Idx;
13914 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13915 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Idx, Info))
13916 return false;
13917
13918 unsigned BitWidth = Val.getBitWidth();
13919 uint64_t Shift = Idx.extractBitsAsZExtValue(numBits: 8, bitPosition: 0);
13920 uint64_t Length = Idx.extractBitsAsZExtValue(numBits: 8, bitPosition: 8);
13921 Length = Length > BitWidth ? BitWidth : Length;
13922
13923 // Handle out of bounds cases.
13924 if (Length == 0 || Shift >= BitWidth)
13925 return Success(Value: 0, E);
13926
13927 uint64_t Result = Val.getZExtValue() >> Shift;
13928 Result &= llvm::maskTrailingOnes<uint64_t>(N: Length);
13929 return Success(Value: Result, E);
13930 }
13931
13932 case clang::X86::BI__builtin_ia32_bzhi_si:
13933 case clang::X86::BI__builtin_ia32_bzhi_di: {
13934 APSInt Val, Idx;
13935 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13936 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Idx, Info))
13937 return false;
13938
13939 unsigned BitWidth = Val.getBitWidth();
13940 unsigned Index = Idx.extractBitsAsZExtValue(numBits: 8, bitPosition: 0);
13941 if (Index < BitWidth)
13942 Val.clearHighBits(hiBits: BitWidth - Index);
13943 return Success(SI: Val, E);
13944 }
13945
13946 case clang::X86::BI__builtin_ia32_lzcnt_u16:
13947 case clang::X86::BI__builtin_ia32_lzcnt_u32:
13948 case clang::X86::BI__builtin_ia32_lzcnt_u64: {
13949 APSInt Val;
13950 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13951 return false;
13952 return Success(Value: Val.countLeadingZeros(), E);
13953 }
13954
13955 case clang::X86::BI__builtin_ia32_tzcnt_u16:
13956 case clang::X86::BI__builtin_ia32_tzcnt_u32:
13957 case clang::X86::BI__builtin_ia32_tzcnt_u64: {
13958 APSInt Val;
13959 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
13960 return false;
13961 return Success(Value: Val.countTrailingZeros(), E);
13962 }
13963
13964 case clang::X86::BI__builtin_ia32_pdep_si:
13965 case clang::X86::BI__builtin_ia32_pdep_di: {
13966 APSInt Val, Msk;
13967 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13968 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Msk, Info))
13969 return false;
13970
13971 unsigned BitWidth = Val.getBitWidth();
13972 APInt Result = APInt::getZero(numBits: BitWidth);
13973 for (unsigned I = 0, P = 0; I != BitWidth; ++I)
13974 if (Msk[I])
13975 Result.setBitVal(BitPosition: I, BitValue: Val[P++]);
13976 return Success(I: Result, E);
13977 }
13978
13979 case clang::X86::BI__builtin_ia32_pext_si:
13980 case clang::X86::BI__builtin_ia32_pext_di: {
13981 APSInt Val, Msk;
13982 if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
13983 !EvaluateInteger(E: E->getArg(Arg: 1), Result&: Msk, Info))
13984 return false;
13985
13986 unsigned BitWidth = Val.getBitWidth();
13987 APInt Result = APInt::getZero(numBits: BitWidth);
13988 for (unsigned I = 0, P = 0; I != BitWidth; ++I)
13989 if (Msk[I])
13990 Result.setBitVal(BitPosition: P++, BitValue: Val[I]);
13991 return Success(I: Result, E);
13992 }
13993 }
13994}
13995
13996/// Determine whether this is a pointer past the end of the complete
13997/// object referred to by the lvalue.
13998static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
13999 const LValue &LV) {
14000 // A null pointer can be viewed as being "past the end" but we don't
14001 // choose to look at it that way here.
14002 if (!LV.getLValueBase())
14003 return false;
14004
14005 // If the designator is valid and refers to a subobject, we're not pointing
14006 // past the end.
14007 if (!LV.getLValueDesignator().Invalid &&
14008 !LV.getLValueDesignator().isOnePastTheEnd())
14009 return false;
14010
14011 // A pointer to an incomplete type might be past-the-end if the type's size is
14012 // zero. We cannot tell because the type is incomplete.
14013 QualType Ty = getType(B: LV.getLValueBase());
14014 if (Ty->isIncompleteType())
14015 return true;
14016
14017 // Can't be past the end of an invalid object.
14018 if (LV.getLValueDesignator().Invalid)
14019 return false;
14020
14021 // We're a past-the-end pointer if we point to the byte after the object,
14022 // no matter what our type or path is.
14023 auto Size = Ctx.getTypeSizeInChars(T: Ty);
14024 return LV.getLValueOffset() == Size;
14025}
14026
14027namespace {
14028
14029/// Data recursive integer evaluator of certain binary operators.
14030///
14031/// We use a data recursive algorithm for binary operators so that we are able
14032/// to handle extreme cases of chained binary operators without causing stack
14033/// overflow.
14034class DataRecursiveIntBinOpEvaluator {
14035 struct EvalResult {
14036 APValue Val;
14037 bool Failed = false;
14038
14039 EvalResult() = default;
14040
14041 void swap(EvalResult &RHS) {
14042 Val.swap(RHS&: RHS.Val);
14043 Failed = RHS.Failed;
14044 RHS.Failed = false;
14045 }
14046 };
14047
14048 struct Job {
14049 const Expr *E;
14050 EvalResult LHSResult; // meaningful only for binary operator expression.
14051 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
14052
14053 Job() = default;
14054 Job(Job &&) = default;
14055
14056 void startSpeculativeEval(EvalInfo &Info) {
14057 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
14058 }
14059
14060 private:
14061 SpeculativeEvaluationRAII SpecEvalRAII;
14062 };
14063
14064 SmallVector<Job, 16> Queue;
14065
14066 IntExprEvaluator &IntEval;
14067 EvalInfo &Info;
14068 APValue &FinalResult;
14069
14070public:
14071 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
14072 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
14073
14074 /// True if \param E is a binary operator that we are going to handle
14075 /// data recursively.
14076 /// We handle binary operators that are comma, logical, or that have operands
14077 /// with integral or enumeration type.
14078 static bool shouldEnqueue(const BinaryOperator *E) {
14079 return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
14080 (E->isPRValue() && E->getType()->isIntegralOrEnumerationType() &&
14081 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
14082 E->getRHS()->getType()->isIntegralOrEnumerationType());
14083 }
14084
14085 bool Traverse(const BinaryOperator *E) {
14086 enqueue(E);
14087 EvalResult PrevResult;
14088 while (!Queue.empty())
14089 process(Result&: PrevResult);
14090
14091 if (PrevResult.Failed) return false;
14092
14093 FinalResult.swap(RHS&: PrevResult.Val);
14094 return true;
14095 }
14096
14097private:
14098 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
14099 return IntEval.Success(Value, E, Result);
14100 }
14101 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
14102 return IntEval.Success(SI: Value, E, Result);
14103 }
14104 bool Error(const Expr *E) {
14105 return IntEval.Error(E);
14106 }
14107 bool Error(const Expr *E, diag::kind D) {
14108 return IntEval.Error(E, D);
14109 }
14110
14111 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
14112 return Info.CCEDiag(E, DiagId: D);
14113 }
14114
14115 // Returns true if visiting the RHS is necessary, false otherwise.
14116 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
14117 bool &SuppressRHSDiags);
14118
14119 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
14120 const BinaryOperator *E, APValue &Result);
14121
14122 void EvaluateExpr(const Expr *E, EvalResult &Result) {
14123 Result.Failed = !Evaluate(Result&: Result.Val, Info, E);
14124 if (Result.Failed)
14125 Result.Val = APValue();
14126 }
14127
14128 void process(EvalResult &Result);
14129
14130 void enqueue(const Expr *E) {
14131 E = E->IgnoreParens();
14132 Queue.resize(N: Queue.size()+1);
14133 Queue.back().E = E;
14134 Queue.back().Kind = Job::AnyExprKind;
14135 }
14136};
14137
14138}
14139
14140bool DataRecursiveIntBinOpEvaluator::
14141 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
14142 bool &SuppressRHSDiags) {
14143 if (E->getOpcode() == BO_Comma) {
14144 // Ignore LHS but note if we could not evaluate it.
14145 if (LHSResult.Failed)
14146 return Info.noteSideEffect();
14147 return true;
14148 }
14149
14150 if (E->isLogicalOp()) {
14151 bool LHSAsBool;
14152 if (!LHSResult.Failed && HandleConversionToBool(Val: LHSResult.Val, Result&: LHSAsBool)) {
14153 // We were able to evaluate the LHS, see if we can get away with not
14154 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
14155 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
14156 Success(Value: LHSAsBool, E, Result&: LHSResult.Val);
14157 return false; // Ignore RHS
14158 }
14159 } else {
14160 LHSResult.Failed = true;
14161
14162 // Since we weren't able to evaluate the left hand side, it
14163 // might have had side effects.
14164 if (!Info.noteSideEffect())
14165 return false;
14166
14167 // We can't evaluate the LHS; however, sometimes the result
14168 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
14169 // Don't ignore RHS and suppress diagnostics from this arm.
14170 SuppressRHSDiags = true;
14171 }
14172
14173 return true;
14174 }
14175
14176 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
14177 E->getRHS()->getType()->isIntegralOrEnumerationType());
14178
14179 if (LHSResult.Failed && !Info.noteFailure())
14180 return false; // Ignore RHS;
14181
14182 return true;
14183}
14184
14185static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
14186 bool IsSub) {
14187 // Compute the new offset in the appropriate width, wrapping at 64 bits.
14188 // FIXME: When compiling for a 32-bit target, we should use 32-bit
14189 // offsets.
14190 assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
14191 CharUnits &Offset = LVal.getLValueOffset();
14192 uint64_t Offset64 = Offset.getQuantity();
14193 uint64_t Index64 = Index.extOrTrunc(width: 64).getZExtValue();
14194 Offset = CharUnits::fromQuantity(Quantity: IsSub ? Offset64 - Index64
14195 : Offset64 + Index64);
14196}
14197
14198bool DataRecursiveIntBinOpEvaluator::
14199 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
14200 const BinaryOperator *E, APValue &Result) {
14201 if (E->getOpcode() == BO_Comma) {
14202 if (RHSResult.Failed)
14203 return false;
14204 Result = RHSResult.Val;
14205 return true;
14206 }
14207
14208 if (E->isLogicalOp()) {
14209 bool lhsResult, rhsResult;
14210 bool LHSIsOK = HandleConversionToBool(Val: LHSResult.Val, Result&: lhsResult);
14211 bool RHSIsOK = HandleConversionToBool(Val: RHSResult.Val, Result&: rhsResult);
14212
14213 if (LHSIsOK) {
14214 if (RHSIsOK) {
14215 if (E->getOpcode() == BO_LOr)
14216 return Success(Value: lhsResult || rhsResult, E, Result);
14217 else
14218 return Success(Value: lhsResult && rhsResult, E, Result);
14219 }
14220 } else {
14221 if (RHSIsOK) {
14222 // We can't evaluate the LHS; however, sometimes the result
14223 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
14224 if (rhsResult == (E->getOpcode() == BO_LOr))
14225 return Success(Value: rhsResult, E, Result);
14226 }
14227 }
14228
14229 return false;
14230 }
14231
14232 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
14233 E->getRHS()->getType()->isIntegralOrEnumerationType());
14234
14235 if (LHSResult.Failed || RHSResult.Failed)
14236 return false;
14237
14238 const APValue &LHSVal = LHSResult.Val;
14239 const APValue &RHSVal = RHSResult.Val;
14240
14241 // Handle cases like (unsigned long)&a + 4.
14242 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
14243 Result = LHSVal;
14244 addOrSubLValueAsInteger(LVal&: Result, Index: RHSVal.getInt(), IsSub: E->getOpcode() == BO_Sub);
14245 return true;
14246 }
14247
14248 // Handle cases like 4 + (unsigned long)&a
14249 if (E->getOpcode() == BO_Add &&
14250 RHSVal.isLValue() && LHSVal.isInt()) {
14251 Result = RHSVal;
14252 addOrSubLValueAsInteger(LVal&: Result, Index: LHSVal.getInt(), /*IsSub*/false);
14253 return true;
14254 }
14255
14256 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
14257 // Handle (intptr_t)&&A - (intptr_t)&&B.
14258 if (!LHSVal.getLValueOffset().isZero() ||
14259 !RHSVal.getLValueOffset().isZero())
14260 return false;
14261 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
14262 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
14263 if (!LHSExpr || !RHSExpr)
14264 return false;
14265 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: LHSExpr);
14266 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: RHSExpr);
14267 if (!LHSAddrExpr || !RHSAddrExpr)
14268 return false;
14269 // Make sure both labels come from the same function.
14270 if (LHSAddrExpr->getLabel()->getDeclContext() !=
14271 RHSAddrExpr->getLabel()->getDeclContext())
14272 return false;
14273 Result = APValue(LHSAddrExpr, RHSAddrExpr);
14274 return true;
14275 }
14276
14277 // All the remaining cases expect both operands to be an integer
14278 if (!LHSVal.isInt() || !RHSVal.isInt())
14279 return Error(E);
14280
14281 // Set up the width and signedness manually, in case it can't be deduced
14282 // from the operation we're performing.
14283 // FIXME: Don't do this in the cases where we can deduce it.
14284 APSInt Value(Info.Ctx.getIntWidth(T: E->getType()),
14285 E->getType()->isUnsignedIntegerOrEnumerationType());
14286 if (!handleIntIntBinOp(Info, E, LHS: LHSVal.getInt(), Opcode: E->getOpcode(),
14287 RHS: RHSVal.getInt(), Result&: Value))
14288 return false;
14289 return Success(Value, E, Result);
14290}
14291
14292void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
14293 Job &job = Queue.back();
14294
14295 switch (job.Kind) {
14296 case Job::AnyExprKind: {
14297 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(Val: job.E)) {
14298 if (shouldEnqueue(E: Bop)) {
14299 job.Kind = Job::BinOpKind;
14300 enqueue(E: Bop->getLHS());
14301 return;
14302 }
14303 }
14304
14305 EvaluateExpr(E: job.E, Result);
14306 Queue.pop_back();
14307 return;
14308 }
14309
14310 case Job::BinOpKind: {
14311 const BinaryOperator *Bop = cast<BinaryOperator>(Val: job.E);
14312 bool SuppressRHSDiags = false;
14313 if (!VisitBinOpLHSOnly(LHSResult&: Result, E: Bop, SuppressRHSDiags)) {
14314 Queue.pop_back();
14315 return;
14316 }
14317 if (SuppressRHSDiags)
14318 job.startSpeculativeEval(Info);
14319 job.LHSResult.swap(RHS&: Result);
14320 job.Kind = Job::BinOpVisitedLHSKind;
14321 enqueue(E: Bop->getRHS());
14322 return;
14323 }
14324
14325 case Job::BinOpVisitedLHSKind: {
14326 const BinaryOperator *Bop = cast<BinaryOperator>(Val: job.E);
14327 EvalResult RHS;
14328 RHS.swap(RHS&: Result);
14329 Result.Failed = !VisitBinOp(LHSResult: job.LHSResult, RHSResult: RHS, E: Bop, Result&: Result.Val);
14330 Queue.pop_back();
14331 return;
14332 }
14333 }
14334
14335 llvm_unreachable("Invalid Job::Kind!");
14336}
14337
14338namespace {
14339enum class CmpResult {
14340 Unequal,
14341 Less,
14342 Equal,
14343 Greater,
14344 Unordered,
14345};
14346}
14347
14348template <class SuccessCB, class AfterCB>
14349static bool
14350EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
14351 SuccessCB &&Success, AfterCB &&DoAfter) {
14352 assert(!E->isValueDependent());
14353 assert(E->isComparisonOp() && "expected comparison operator");
14354 assert((E->getOpcode() == BO_Cmp ||
14355 E->getType()->isIntegralOrEnumerationType()) &&
14356 "unsupported binary expression evaluation");
14357 auto Error = [&](const Expr *E) {
14358 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
14359 return false;
14360 };
14361
14362 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
14363 bool IsEquality = E->isEqualityOp();
14364
14365 QualType LHSTy = E->getLHS()->getType();
14366 QualType RHSTy = E->getRHS()->getType();
14367
14368 if (LHSTy->isIntegralOrEnumerationType() &&
14369 RHSTy->isIntegralOrEnumerationType()) {
14370 APSInt LHS, RHS;
14371 bool LHSOK = EvaluateInteger(E: E->getLHS(), Result&: LHS, Info);
14372 if (!LHSOK && !Info.noteFailure())
14373 return false;
14374 if (!EvaluateInteger(E: E->getRHS(), Result&: RHS, Info) || !LHSOK)
14375 return false;
14376 if (LHS < RHS)
14377 return Success(CmpResult::Less, E);
14378 if (LHS > RHS)
14379 return Success(CmpResult::Greater, E);
14380 return Success(CmpResult::Equal, E);
14381 }
14382
14383 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
14384 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(Ty: LHSTy));
14385 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(Ty: RHSTy));
14386
14387 bool LHSOK = EvaluateFixedPointOrInteger(E: E->getLHS(), Result&: LHSFX, Info);
14388 if (!LHSOK && !Info.noteFailure())
14389 return false;
14390 if (!EvaluateFixedPointOrInteger(E: E->getRHS(), Result&: RHSFX, Info) || !LHSOK)
14391 return false;
14392 if (LHSFX < RHSFX)
14393 return Success(CmpResult::Less, E);
14394 if (LHSFX > RHSFX)
14395 return Success(CmpResult::Greater, E);
14396 return Success(CmpResult::Equal, E);
14397 }
14398
14399 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
14400 ComplexValue LHS, RHS;
14401 bool LHSOK;
14402 if (E->isAssignmentOp()) {
14403 LValue LV;
14404 EvaluateLValue(E: E->getLHS(), Result&: LV, Info);
14405 LHSOK = false;
14406 } else if (LHSTy->isRealFloatingType()) {
14407 LHSOK = EvaluateFloat(E: E->getLHS(), Result&: LHS.FloatReal, Info);
14408 if (LHSOK) {
14409 LHS.makeComplexFloat();
14410 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
14411 }
14412 } else {
14413 LHSOK = EvaluateComplex(E: E->getLHS(), Res&: LHS, Info);
14414 }
14415 if (!LHSOK && !Info.noteFailure())
14416 return false;
14417
14418 if (E->getRHS()->getType()->isRealFloatingType()) {
14419 if (!EvaluateFloat(E: E->getRHS(), Result&: RHS.FloatReal, Info) || !LHSOK)
14420 return false;
14421 RHS.makeComplexFloat();
14422 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
14423 } else if (!EvaluateComplex(E: E->getRHS(), Res&: RHS, Info) || !LHSOK)
14424 return false;
14425
14426 if (LHS.isComplexFloat()) {
14427 APFloat::cmpResult CR_r =
14428 LHS.getComplexFloatReal().compare(RHS: RHS.getComplexFloatReal());
14429 APFloat::cmpResult CR_i =
14430 LHS.getComplexFloatImag().compare(RHS: RHS.getComplexFloatImag());
14431 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
14432 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
14433 } else {
14434 assert(IsEquality && "invalid complex comparison");
14435 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
14436 LHS.getComplexIntImag() == RHS.getComplexIntImag();
14437 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
14438 }
14439 }
14440
14441 if (LHSTy->isRealFloatingType() &&
14442 RHSTy->isRealFloatingType()) {
14443 APFloat RHS(0.0), LHS(0.0);
14444
14445 bool LHSOK = EvaluateFloat(E: E->getRHS(), Result&: RHS, Info);
14446 if (!LHSOK && !Info.noteFailure())
14447 return false;
14448
14449 if (!EvaluateFloat(E: E->getLHS(), Result&: LHS, Info) || !LHSOK)
14450 return false;
14451
14452 assert(E->isComparisonOp() && "Invalid binary operator!");
14453 llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS);
14454 if (!Info.InConstantContext &&
14455 APFloatCmpResult == APFloat::cmpUnordered &&
14456 E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts()).isFPConstrained()) {
14457 // Note: Compares may raise invalid in some cases involving NaN or sNaN.
14458 Info.FFDiag(E, DiagId: diag::note_constexpr_float_arithmetic_strict);
14459 return false;
14460 }
14461 auto GetCmpRes = [&]() {
14462 switch (APFloatCmpResult) {
14463 case APFloat::cmpEqual:
14464 return CmpResult::Equal;
14465 case APFloat::cmpLessThan:
14466 return CmpResult::Less;
14467 case APFloat::cmpGreaterThan:
14468 return CmpResult::Greater;
14469 case APFloat::cmpUnordered:
14470 return CmpResult::Unordered;
14471 }
14472 llvm_unreachable("Unrecognised APFloat::cmpResult enum");
14473 };
14474 return Success(GetCmpRes(), E);
14475 }
14476
14477 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
14478 LValue LHSValue, RHSValue;
14479
14480 bool LHSOK = EvaluatePointer(E: E->getLHS(), Result&: LHSValue, Info);
14481 if (!LHSOK && !Info.noteFailure())
14482 return false;
14483
14484 if (!EvaluatePointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
14485 return false;
14486
14487 // If we have Unknown pointers we should fail if they are not global values.
14488 if (!(IsGlobalLValue(B: LHSValue.getLValueBase()) &&
14489 IsGlobalLValue(B: RHSValue.getLValueBase())) &&
14490 (LHSValue.AllowConstexprUnknown || RHSValue.AllowConstexprUnknown))
14491 return false;
14492
14493 // Reject differing bases from the normal codepath; we special-case
14494 // comparisons to null.
14495 if (!HasSameBase(A: LHSValue, B: RHSValue)) {
14496 auto DiagComparison = [&] (unsigned DiagID, bool Reversed = false) {
14497 std::string LHS = LHSValue.toString(Ctx&: Info.Ctx, T: E->getLHS()->getType());
14498 std::string RHS = RHSValue.toString(Ctx&: Info.Ctx, T: E->getRHS()->getType());
14499 Info.FFDiag(E, DiagId: DiagID)
14500 << (Reversed ? RHS : LHS) << (Reversed ? LHS : RHS);
14501 return false;
14502 };
14503 // Inequalities and subtractions between unrelated pointers have
14504 // unspecified or undefined behavior.
14505 if (!IsEquality)
14506 return DiagComparison(
14507 diag::note_constexpr_pointer_comparison_unspecified);
14508 // A constant address may compare equal to the address of a symbol.
14509 // The one exception is that address of an object cannot compare equal
14510 // to a null pointer constant.
14511 // TODO: Should we restrict this to actual null pointers, and exclude the
14512 // case of zero cast to pointer type?
14513 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
14514 (!RHSValue.Base && !RHSValue.Offset.isZero()))
14515 return DiagComparison(diag::note_constexpr_pointer_constant_comparison,
14516 !RHSValue.Base);
14517 // C++2c [intro.object]/10:
14518 // Two objects [...] may have the same address if [...] they are both
14519 // potentially non-unique objects.
14520 // C++2c [intro.object]/9:
14521 // An object is potentially non-unique if it is a string literal object,
14522 // the backing array of an initializer list, or a subobject thereof.
14523 //
14524 // This makes the comparison result unspecified, so it's not a constant
14525 // expression.
14526 //
14527 // TODO: Do we need to handle the initializer list case here?
14528 if (ArePotentiallyOverlappingStringLiterals(Info, LHS: LHSValue, RHS: RHSValue))
14529 return DiagComparison(diag::note_constexpr_literal_comparison);
14530 if (IsOpaqueConstantCall(LVal: LHSValue) || IsOpaqueConstantCall(LVal: RHSValue))
14531 return DiagComparison(diag::note_constexpr_opaque_call_comparison,
14532 !IsOpaqueConstantCall(LVal: LHSValue));
14533 // We can't tell whether weak symbols will end up pointing to the same
14534 // object.
14535 if (IsWeakLValue(Value: LHSValue) || IsWeakLValue(Value: RHSValue))
14536 return DiagComparison(diag::note_constexpr_pointer_weak_comparison,
14537 !IsWeakLValue(Value: LHSValue));
14538 // We can't compare the address of the start of one object with the
14539 // past-the-end address of another object, per C++ DR1652.
14540 if (LHSValue.Base && LHSValue.Offset.isZero() &&
14541 isOnePastTheEndOfCompleteObject(Ctx: Info.Ctx, LV: RHSValue))
14542 return DiagComparison(diag::note_constexpr_pointer_comparison_past_end,
14543 true);
14544 if (RHSValue.Base && RHSValue.Offset.isZero() &&
14545 isOnePastTheEndOfCompleteObject(Ctx: Info.Ctx, LV: LHSValue))
14546 return DiagComparison(diag::note_constexpr_pointer_comparison_past_end,
14547 false);
14548 // We can't tell whether an object is at the same address as another
14549 // zero sized object.
14550 if ((RHSValue.Base && isZeroSized(Value: LHSValue)) ||
14551 (LHSValue.Base && isZeroSized(Value: RHSValue)))
14552 return DiagComparison(
14553 diag::note_constexpr_pointer_comparison_zero_sized);
14554 return Success(CmpResult::Unequal, E);
14555 }
14556
14557 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
14558 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
14559
14560 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
14561 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
14562
14563 // C++11 [expr.rel]p2:
14564 // - If two pointers point to non-static data members of the same object,
14565 // or to subobjects or array elements fo such members, recursively, the
14566 // pointer to the later declared member compares greater provided the
14567 // two members have the same access control and provided their class is
14568 // not a union.
14569 // [...]
14570 // - Otherwise pointer comparisons are unspecified.
14571 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
14572 bool WasArrayIndex;
14573 unsigned Mismatch = FindDesignatorMismatch(
14574 ObjType: getType(B: LHSValue.Base), A: LHSDesignator, B: RHSDesignator, WasArrayIndex);
14575 // At the point where the designators diverge, the comparison has a
14576 // specified value if:
14577 // - we are comparing array indices
14578 // - we are comparing fields of a union, or fields with the same access
14579 // Otherwise, the result is unspecified and thus the comparison is not a
14580 // constant expression.
14581 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
14582 Mismatch < RHSDesignator.Entries.size()) {
14583 const FieldDecl *LF = getAsField(E: LHSDesignator.Entries[Mismatch]);
14584 const FieldDecl *RF = getAsField(E: RHSDesignator.Entries[Mismatch]);
14585 if (!LF && !RF)
14586 Info.CCEDiag(E, DiagId: diag::note_constexpr_pointer_comparison_base_classes);
14587 else if (!LF)
14588 Info.CCEDiag(E, DiagId: diag::note_constexpr_pointer_comparison_base_field)
14589 << getAsBaseClass(E: LHSDesignator.Entries[Mismatch])
14590 << RF->getParent() << RF;
14591 else if (!RF)
14592 Info.CCEDiag(E, DiagId: diag::note_constexpr_pointer_comparison_base_field)
14593 << getAsBaseClass(E: RHSDesignator.Entries[Mismatch])
14594 << LF->getParent() << LF;
14595 else if (!LF->getParent()->isUnion() &&
14596 LF->getAccess() != RF->getAccess())
14597 Info.CCEDiag(E,
14598 DiagId: diag::note_constexpr_pointer_comparison_differing_access)
14599 << LF << LF->getAccess() << RF << RF->getAccess()
14600 << LF->getParent();
14601 }
14602 }
14603
14604 // The comparison here must be unsigned, and performed with the same
14605 // width as the pointer.
14606 unsigned PtrSize = Info.Ctx.getTypeSize(T: LHSTy);
14607 uint64_t CompareLHS = LHSOffset.getQuantity();
14608 uint64_t CompareRHS = RHSOffset.getQuantity();
14609 assert(PtrSize <= 64 && "Unexpected pointer width");
14610 uint64_t Mask = ~0ULL >> (64 - PtrSize);
14611 CompareLHS &= Mask;
14612 CompareRHS &= Mask;
14613
14614 // If there is a base and this is a relational operator, we can only
14615 // compare pointers within the object in question; otherwise, the result
14616 // depends on where the object is located in memory.
14617 if (!LHSValue.Base.isNull() && IsRelational) {
14618 QualType BaseTy = getType(B: LHSValue.Base);
14619 if (BaseTy->isIncompleteType())
14620 return Error(E);
14621 CharUnits Size = Info.Ctx.getTypeSizeInChars(T: BaseTy);
14622 uint64_t OffsetLimit = Size.getQuantity();
14623 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
14624 return Error(E);
14625 }
14626
14627 if (CompareLHS < CompareRHS)
14628 return Success(CmpResult::Less, E);
14629 if (CompareLHS > CompareRHS)
14630 return Success(CmpResult::Greater, E);
14631 return Success(CmpResult::Equal, E);
14632 }
14633
14634 if (LHSTy->isMemberPointerType()) {
14635 assert(IsEquality && "unexpected member pointer operation");
14636 assert(RHSTy->isMemberPointerType() && "invalid comparison");
14637
14638 MemberPtr LHSValue, RHSValue;
14639
14640 bool LHSOK = EvaluateMemberPointer(E: E->getLHS(), Result&: LHSValue, Info);
14641 if (!LHSOK && !Info.noteFailure())
14642 return false;
14643
14644 if (!EvaluateMemberPointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
14645 return false;
14646
14647 // If either operand is a pointer to a weak function, the comparison is not
14648 // constant.
14649 if (LHSValue.getDecl() && LHSValue.getDecl()->isWeak()) {
14650 Info.FFDiag(E, DiagId: diag::note_constexpr_mem_pointer_weak_comparison)
14651 << LHSValue.getDecl();
14652 return false;
14653 }
14654 if (RHSValue.getDecl() && RHSValue.getDecl()->isWeak()) {
14655 Info.FFDiag(E, DiagId: diag::note_constexpr_mem_pointer_weak_comparison)
14656 << RHSValue.getDecl();
14657 return false;
14658 }
14659
14660 // C++11 [expr.eq]p2:
14661 // If both operands are null, they compare equal. Otherwise if only one is
14662 // null, they compare unequal.
14663 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
14664 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
14665 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
14666 }
14667
14668 // Otherwise if either is a pointer to a virtual member function, the
14669 // result is unspecified.
14670 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: LHSValue.getDecl()))
14671 if (MD->isVirtual())
14672 Info.CCEDiag(E, DiagId: diag::note_constexpr_compare_virtual_mem_ptr) << MD;
14673 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: RHSValue.getDecl()))
14674 if (MD->isVirtual())
14675 Info.CCEDiag(E, DiagId: diag::note_constexpr_compare_virtual_mem_ptr) << MD;
14676
14677 // Otherwise they compare equal if and only if they would refer to the
14678 // same member of the same most derived object or the same subobject if
14679 // they were dereferenced with a hypothetical object of the associated
14680 // class type.
14681 bool Equal = LHSValue == RHSValue;
14682 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
14683 }
14684
14685 if (LHSTy->isNullPtrType()) {
14686 assert(E->isComparisonOp() && "unexpected nullptr operation");
14687 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
14688 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
14689 // are compared, the result is true of the operator is <=, >= or ==, and
14690 // false otherwise.
14691 LValue Res;
14692 if (!EvaluatePointer(E: E->getLHS(), Result&: Res, Info) ||
14693 !EvaluatePointer(E: E->getRHS(), Result&: Res, Info))
14694 return false;
14695 return Success(CmpResult::Equal, E);
14696 }
14697
14698 return DoAfter();
14699}
14700
14701bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
14702 if (!CheckLiteralType(Info, E))
14703 return false;
14704
14705 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
14706 ComparisonCategoryResult CCR;
14707 switch (CR) {
14708 case CmpResult::Unequal:
14709 llvm_unreachable("should never produce Unequal for three-way comparison");
14710 case CmpResult::Less:
14711 CCR = ComparisonCategoryResult::Less;
14712 break;
14713 case CmpResult::Equal:
14714 CCR = ComparisonCategoryResult::Equal;
14715 break;
14716 case CmpResult::Greater:
14717 CCR = ComparisonCategoryResult::Greater;
14718 break;
14719 case CmpResult::Unordered:
14720 CCR = ComparisonCategoryResult::Unordered;
14721 break;
14722 }
14723 // Evaluation succeeded. Lookup the information for the comparison category
14724 // type and fetch the VarDecl for the result.
14725 const ComparisonCategoryInfo &CmpInfo =
14726 Info.Ctx.CompCategories.getInfoForType(Ty: E->getType());
14727 const VarDecl *VD = CmpInfo.getValueInfo(ValueKind: CmpInfo.makeWeakResult(Res: CCR))->VD;
14728 // Check and evaluate the result as a constant expression.
14729 LValue LV;
14730 LV.set(B: VD);
14731 if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getType(), LVal: LV, RVal&: Result))
14732 return false;
14733 return CheckConstantExpression(Info, DiagLoc: E->getExprLoc(), Type: E->getType(), Value: Result,
14734 Kind: ConstantExprKind::Normal);
14735 };
14736 return EvaluateComparisonBinaryOperator(Info, E, Success&: OnSuccess, DoAfter: [&]() {
14737 return ExprEvaluatorBaseTy::VisitBinCmp(S: E);
14738 });
14739}
14740
14741bool RecordExprEvaluator::VisitCXXParenListInitExpr(
14742 const CXXParenListInitExpr *E) {
14743 return VisitCXXParenListOrInitListExpr(ExprToVisit: E, Args: E->getInitExprs());
14744}
14745
14746bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
14747 // We don't support assignment in C. C++ assignments don't get here because
14748 // assignment is an lvalue in C++.
14749 if (E->isAssignmentOp()) {
14750 Error(E);
14751 if (!Info.noteFailure())
14752 return false;
14753 }
14754
14755 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
14756 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
14757
14758 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||
14759 !E->getRHS()->getType()->isIntegralOrEnumerationType()) &&
14760 "DataRecursiveIntBinOpEvaluator should have handled integral types");
14761
14762 if (E->isComparisonOp()) {
14763 // Evaluate builtin binary comparisons by evaluating them as three-way
14764 // comparisons and then translating the result.
14765 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
14766 assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&
14767 "should only produce Unequal for equality comparisons");
14768 bool IsEqual = CR == CmpResult::Equal,
14769 IsLess = CR == CmpResult::Less,
14770 IsGreater = CR == CmpResult::Greater;
14771 auto Op = E->getOpcode();
14772 switch (Op) {
14773 default:
14774 llvm_unreachable("unsupported binary operator");
14775 case BO_EQ:
14776 case BO_NE:
14777 return Success(Value: IsEqual == (Op == BO_EQ), E);
14778 case BO_LT:
14779 return Success(Value: IsLess, E);
14780 case BO_GT:
14781 return Success(Value: IsGreater, E);
14782 case BO_LE:
14783 return Success(Value: IsEqual || IsLess, E);
14784 case BO_GE:
14785 return Success(Value: IsEqual || IsGreater, E);
14786 }
14787 };
14788 return EvaluateComparisonBinaryOperator(Info, E, Success&: OnSuccess, DoAfter: [&]() {
14789 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14790 });
14791 }
14792
14793 QualType LHSTy = E->getLHS()->getType();
14794 QualType RHSTy = E->getRHS()->getType();
14795
14796 if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
14797 E->getOpcode() == BO_Sub) {
14798 LValue LHSValue, RHSValue;
14799
14800 bool LHSOK = EvaluatePointer(E: E->getLHS(), Result&: LHSValue, Info);
14801 if (!LHSOK && !Info.noteFailure())
14802 return false;
14803
14804 if (!EvaluatePointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
14805 return false;
14806
14807 // Reject differing bases from the normal codepath; we special-case
14808 // comparisons to null.
14809 if (!HasSameBase(A: LHSValue, B: RHSValue)) {
14810 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
14811 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
14812
14813 auto DiagArith = [&](unsigned DiagID) {
14814 std::string LHS = LHSValue.toString(Ctx&: Info.Ctx, T: E->getLHS()->getType());
14815 std::string RHS = RHSValue.toString(Ctx&: Info.Ctx, T: E->getRHS()->getType());
14816 Info.FFDiag(E, DiagId: DiagID) << LHS << RHS;
14817 if (LHSExpr && LHSExpr == RHSExpr)
14818 Info.Note(Loc: LHSExpr->getExprLoc(),
14819 DiagId: diag::note_constexpr_repeated_literal_eval)
14820 << LHSExpr->getSourceRange();
14821 return false;
14822 };
14823
14824 if (!LHSExpr || !RHSExpr)
14825 return DiagArith(diag::note_constexpr_pointer_arith_unspecified);
14826
14827 if (ArePotentiallyOverlappingStringLiterals(Info, LHS: LHSValue, RHS: RHSValue))
14828 return DiagArith(diag::note_constexpr_literal_arith);
14829
14830 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: LHSExpr);
14831 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: RHSExpr);
14832 if (!LHSAddrExpr || !RHSAddrExpr)
14833 return Error(E);
14834 // Make sure both labels come from the same function.
14835 if (LHSAddrExpr->getLabel()->getDeclContext() !=
14836 RHSAddrExpr->getLabel()->getDeclContext())
14837 return Error(E);
14838 return Success(V: APValue(LHSAddrExpr, RHSAddrExpr), E);
14839 }
14840 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
14841 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
14842
14843 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
14844 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
14845
14846 // C++11 [expr.add]p6:
14847 // Unless both pointers point to elements of the same array object, or
14848 // one past the last element of the array object, the behavior is
14849 // undefined.
14850 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
14851 !AreElementsOfSameArray(ObjType: getType(B: LHSValue.Base), A: LHSDesignator,
14852 B: RHSDesignator))
14853 Info.CCEDiag(E, DiagId: diag::note_constexpr_pointer_subtraction_not_same_array);
14854
14855 QualType Type = E->getLHS()->getType();
14856 QualType ElementType = Type->castAs<PointerType>()->getPointeeType();
14857
14858 CharUnits ElementSize;
14859 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: ElementType, Size&: ElementSize))
14860 return false;
14861
14862 // As an extension, a type may have zero size (empty struct or union in
14863 // C, array of zero length). Pointer subtraction in such cases has
14864 // undefined behavior, so is not constant.
14865 if (ElementSize.isZero()) {
14866 Info.FFDiag(E, DiagId: diag::note_constexpr_pointer_subtraction_zero_size)
14867 << ElementType;
14868 return false;
14869 }
14870
14871 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
14872 // and produce incorrect results when it overflows. Such behavior
14873 // appears to be non-conforming, but is common, so perhaps we should
14874 // assume the standard intended for such cases to be undefined behavior
14875 // and check for them.
14876
14877 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
14878 // overflow in the final conversion to ptrdiff_t.
14879 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
14880 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
14881 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
14882 false);
14883 APSInt TrueResult = (LHS - RHS) / ElemSize;
14884 APSInt Result = TrueResult.trunc(width: Info.Ctx.getIntWidth(T: E->getType()));
14885
14886 if (Result.extend(width: 65) != TrueResult &&
14887 !HandleOverflow(Info, E, SrcValue: TrueResult, DestType: E->getType()))
14888 return false;
14889 return Success(SI: Result, E);
14890 }
14891
14892 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14893}
14894
14895/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
14896/// a result as the expression's type.
14897bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
14898 const UnaryExprOrTypeTraitExpr *E) {
14899 switch(E->getKind()) {
14900 case UETT_PreferredAlignOf:
14901 case UETT_AlignOf: {
14902 if (E->isArgumentType())
14903 return Success(
14904 Size: GetAlignOfType(Ctx: Info.Ctx, T: E->getArgumentType(), ExprKind: E->getKind()), E);
14905 else
14906 return Success(
14907 Size: GetAlignOfExpr(Ctx: Info.Ctx, E: E->getArgumentExpr(), ExprKind: E->getKind()), E);
14908 }
14909
14910 case UETT_PtrAuthTypeDiscriminator: {
14911 if (E->getArgumentType()->isDependentType())
14912 return false;
14913 return Success(
14914 Value: Info.Ctx.getPointerAuthTypeDiscriminator(T: E->getArgumentType()), E);
14915 }
14916 case UETT_VecStep: {
14917 QualType Ty = E->getTypeOfArgument();
14918
14919 if (Ty->isVectorType()) {
14920 unsigned n = Ty->castAs<VectorType>()->getNumElements();
14921
14922 // The vec_step built-in functions that take a 3-component
14923 // vector return 4. (OpenCL 1.1 spec 6.11.12)
14924 if (n == 3)
14925 n = 4;
14926
14927 return Success(Value: n, E);
14928 } else
14929 return Success(Value: 1, E);
14930 }
14931
14932 case UETT_DataSizeOf:
14933 case UETT_SizeOf: {
14934 QualType SrcTy = E->getTypeOfArgument();
14935 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
14936 // the result is the size of the referenced type."
14937 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
14938 SrcTy = Ref->getPointeeType();
14939
14940 CharUnits Sizeof;
14941 if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: SrcTy, Size&: Sizeof,
14942 SOT: E->getKind() == UETT_DataSizeOf ? SizeOfType::DataSizeOf
14943 : SizeOfType::SizeOf)) {
14944 return false;
14945 }
14946 return Success(Size: Sizeof, E);
14947 }
14948 case UETT_OpenMPRequiredSimdAlign:
14949 assert(E->isArgumentType());
14950 return Success(
14951 Value: Info.Ctx.toCharUnitsFromBits(
14952 BitSize: Info.Ctx.getOpenMPDefaultSimdAlign(T: E->getArgumentType()))
14953 .getQuantity(),
14954 E);
14955 case UETT_VectorElements: {
14956 QualType Ty = E->getTypeOfArgument();
14957 // If the vector has a fixed size, we can determine the number of elements
14958 // at compile time.
14959 if (const auto *VT = Ty->getAs<VectorType>())
14960 return Success(Value: VT->getNumElements(), E);
14961
14962 assert(Ty->isSizelessVectorType());
14963 if (Info.InConstantContext)
14964 Info.CCEDiag(E, DiagId: diag::note_constexpr_non_const_vectorelements)
14965 << E->getSourceRange();
14966
14967 return false;
14968 }
14969 case UETT_CountOf: {
14970 QualType Ty = E->getTypeOfArgument();
14971 assert(Ty->isArrayType());
14972
14973 // We don't need to worry about array element qualifiers, so getting the
14974 // unsafe array type is fine.
14975 if (const auto *CAT =
14976 dyn_cast<ConstantArrayType>(Val: Ty->getAsArrayTypeUnsafe())) {
14977 return Success(I: CAT->getSize(), E);
14978 }
14979
14980 assert(!Ty->isConstantSizeType());
14981
14982 // If it's a variable-length array type, we need to check whether it is a
14983 // multidimensional array. If so, we need to check the size expression of
14984 // the VLA to see if it's a constant size. If so, we can return that value.
14985 const auto *VAT = Info.Ctx.getAsVariableArrayType(T: Ty);
14986 assert(VAT);
14987 if (VAT->getElementType()->isArrayType()) {
14988 std::optional<APSInt> Res =
14989 VAT->getSizeExpr()->getIntegerConstantExpr(Ctx: Info.Ctx);
14990 if (Res) {
14991 // The resulting value always has type size_t, so we need to make the
14992 // returned APInt have the correct sign and bit-width.
14993 APInt Val{
14994 static_cast<unsigned>(Info.Ctx.getTypeSize(T: Info.Ctx.getSizeType())),
14995 Res->getZExtValue()};
14996 return Success(I: Val, E);
14997 }
14998 }
14999
15000 // Definitely a variable-length type, which is not an ICE.
15001 // FIXME: Better diagnostic.
15002 Info.FFDiag(Loc: E->getBeginLoc());
15003 return false;
15004 }
15005 }
15006
15007 llvm_unreachable("unknown expr/type trait");
15008}
15009
15010bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
15011 CharUnits Result;
15012 unsigned n = OOE->getNumComponents();
15013 if (n == 0)
15014 return Error(E: OOE);
15015 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
15016 for (unsigned i = 0; i != n; ++i) {
15017 OffsetOfNode ON = OOE->getComponent(Idx: i);
15018 switch (ON.getKind()) {
15019 case OffsetOfNode::Array: {
15020 const Expr *Idx = OOE->getIndexExpr(Idx: ON.getArrayExprIndex());
15021 APSInt IdxResult;
15022 if (!EvaluateInteger(E: Idx, Result&: IdxResult, Info))
15023 return false;
15024 const ArrayType *AT = Info.Ctx.getAsArrayType(T: CurrentType);
15025 if (!AT)
15026 return Error(E: OOE);
15027 CurrentType = AT->getElementType();
15028 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(T: CurrentType);
15029 Result += IdxResult.getSExtValue() * ElementSize;
15030 break;
15031 }
15032
15033 case OffsetOfNode::Field: {
15034 FieldDecl *MemberDecl = ON.getField();
15035 const RecordType *RT = CurrentType->getAs<RecordType>();
15036 if (!RT)
15037 return Error(E: OOE);
15038 RecordDecl *RD = RT->getDecl();
15039 if (RD->isInvalidDecl()) return false;
15040 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(D: RD);
15041 unsigned i = MemberDecl->getFieldIndex();
15042 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
15043 Result += Info.Ctx.toCharUnitsFromBits(BitSize: RL.getFieldOffset(FieldNo: i));
15044 CurrentType = MemberDecl->getType().getNonReferenceType();
15045 break;
15046 }
15047
15048 case OffsetOfNode::Identifier:
15049 llvm_unreachable("dependent __builtin_offsetof");
15050
15051 case OffsetOfNode::Base: {
15052 CXXBaseSpecifier *BaseSpec = ON.getBase();
15053 if (BaseSpec->isVirtual())
15054 return Error(E: OOE);
15055
15056 // Find the layout of the class whose base we are looking into.
15057 const RecordType *RT = CurrentType->getAs<RecordType>();
15058 if (!RT)
15059 return Error(E: OOE);
15060 RecordDecl *RD = RT->getDecl();
15061 if (RD->isInvalidDecl()) return false;
15062 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(D: RD);
15063
15064 // Find the base class itself.
15065 CurrentType = BaseSpec->getType();
15066 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
15067 if (!BaseRT)
15068 return Error(E: OOE);
15069
15070 // Add the offset to the base.
15071 Result += RL.getBaseClassOffset(Base: cast<CXXRecordDecl>(Val: BaseRT->getDecl()));
15072 break;
15073 }
15074 }
15075 }
15076 return Success(Size: Result, E: OOE);
15077}
15078
15079bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
15080 switch (E->getOpcode()) {
15081 default:
15082 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
15083 // See C99 6.6p3.
15084 return Error(E);
15085 case UO_Extension:
15086 // FIXME: Should extension allow i-c-e extension expressions in its scope?
15087 // If so, we could clear the diagnostic ID.
15088 return Visit(S: E->getSubExpr());
15089 case UO_Plus:
15090 // The result is just the value.
15091 return Visit(S: E->getSubExpr());
15092 case UO_Minus: {
15093 if (!Visit(S: E->getSubExpr()))
15094 return false;
15095 if (!Result.isInt()) return Error(E);
15096 const APSInt &Value = Result.getInt();
15097 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow()) {
15098 if (Info.checkingForUndefinedBehavior())
15099 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
15100 DiagID: diag::warn_integer_constant_overflow)
15101 << toString(I: Value, Radix: 10, Signed: Value.isSigned(), /*formatAsCLiteral=*/false,
15102 /*UpperCase=*/true, /*InsertSeparators=*/true)
15103 << E->getType() << E->getSourceRange();
15104
15105 if (!HandleOverflow(Info, E, SrcValue: -Value.extend(width: Value.getBitWidth() + 1),
15106 DestType: E->getType()))
15107 return false;
15108 }
15109 return Success(SI: -Value, E);
15110 }
15111 case UO_Not: {
15112 if (!Visit(S: E->getSubExpr()))
15113 return false;
15114 if (!Result.isInt()) return Error(E);
15115 return Success(SI: ~Result.getInt(), E);
15116 }
15117 case UO_LNot: {
15118 bool bres;
15119 if (!EvaluateAsBooleanCondition(E: E->getSubExpr(), Result&: bres, Info))
15120 return false;
15121 return Success(Value: !bres, E);
15122 }
15123 }
15124}
15125
15126/// HandleCast - This is used to evaluate implicit or explicit casts where the
15127/// result type is integer.
15128bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
15129 const Expr *SubExpr = E->getSubExpr();
15130 QualType DestType = E->getType();
15131 QualType SrcType = SubExpr->getType();
15132
15133 switch (E->getCastKind()) {
15134 case CK_BaseToDerived:
15135 case CK_DerivedToBase:
15136 case CK_UncheckedDerivedToBase:
15137 case CK_Dynamic:
15138 case CK_ToUnion:
15139 case CK_ArrayToPointerDecay:
15140 case CK_FunctionToPointerDecay:
15141 case CK_NullToPointer:
15142 case CK_NullToMemberPointer:
15143 case CK_BaseToDerivedMemberPointer:
15144 case CK_DerivedToBaseMemberPointer:
15145 case CK_ReinterpretMemberPointer:
15146 case CK_ConstructorConversion:
15147 case CK_IntegralToPointer:
15148 case CK_ToVoid:
15149 case CK_VectorSplat:
15150 case CK_IntegralToFloating:
15151 case CK_FloatingCast:
15152 case CK_CPointerToObjCPointerCast:
15153 case CK_BlockPointerToObjCPointerCast:
15154 case CK_AnyPointerToBlockPointerCast:
15155 case CK_ObjCObjectLValueCast:
15156 case CK_FloatingRealToComplex:
15157 case CK_FloatingComplexToReal:
15158 case CK_FloatingComplexCast:
15159 case CK_FloatingComplexToIntegralComplex:
15160 case CK_IntegralRealToComplex:
15161 case CK_IntegralComplexCast:
15162 case CK_IntegralComplexToFloatingComplex:
15163 case CK_BuiltinFnToFnPtr:
15164 case CK_ZeroToOCLOpaqueType:
15165 case CK_NonAtomicToAtomic:
15166 case CK_AddressSpaceConversion:
15167 case CK_IntToOCLSampler:
15168 case CK_FloatingToFixedPoint:
15169 case CK_FixedPointToFloating:
15170 case CK_FixedPointCast:
15171 case CK_IntegralToFixedPoint:
15172 case CK_MatrixCast:
15173 case CK_HLSLAggregateSplatCast:
15174 llvm_unreachable("invalid cast kind for integral value");
15175
15176 case CK_BitCast:
15177 case CK_Dependent:
15178 case CK_LValueBitCast:
15179 case CK_ARCProduceObject:
15180 case CK_ARCConsumeObject:
15181 case CK_ARCReclaimReturnedObject:
15182 case CK_ARCExtendBlockObject:
15183 case CK_CopyAndAutoreleaseBlockObject:
15184 return Error(E);
15185
15186 case CK_UserDefinedConversion:
15187 case CK_LValueToRValue:
15188 case CK_AtomicToNonAtomic:
15189 case CK_NoOp:
15190 case CK_LValueToRValueBitCast:
15191 case CK_HLSLArrayRValue:
15192 case CK_HLSLElementwiseCast:
15193 return ExprEvaluatorBaseTy::VisitCastExpr(E);
15194
15195 case CK_MemberPointerToBoolean:
15196 case CK_PointerToBoolean:
15197 case CK_IntegralToBoolean:
15198 case CK_FloatingToBoolean:
15199 case CK_BooleanToSignedIntegral:
15200 case CK_FloatingComplexToBoolean:
15201 case CK_IntegralComplexToBoolean: {
15202 bool BoolResult;
15203 if (!EvaluateAsBooleanCondition(E: SubExpr, Result&: BoolResult, Info))
15204 return false;
15205 uint64_t IntResult = BoolResult;
15206 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
15207 IntResult = (uint64_t)-1;
15208 return Success(Value: IntResult, E);
15209 }
15210
15211 case CK_FixedPointToIntegral: {
15212 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(Ty: SrcType));
15213 if (!EvaluateFixedPoint(E: SubExpr, Result&: Src, Info))
15214 return false;
15215 bool Overflowed;
15216 llvm::APSInt Result = Src.convertToInt(
15217 DstWidth: Info.Ctx.getIntWidth(T: DestType),
15218 DstSign: DestType->isSignedIntegerOrEnumerationType(), Overflow: &Overflowed);
15219 if (Overflowed && !HandleOverflow(Info, E, SrcValue: Result, DestType))
15220 return false;
15221 return Success(SI: Result, E);
15222 }
15223
15224 case CK_FixedPointToBoolean: {
15225 // Unsigned padding does not affect this.
15226 APValue Val;
15227 if (!Evaluate(Result&: Val, Info, E: SubExpr))
15228 return false;
15229 return Success(Value: Val.getFixedPoint().getBoolValue(), E);
15230 }
15231
15232 case CK_IntegralCast: {
15233 if (!Visit(S: SubExpr))
15234 return false;
15235
15236 if (!Result.isInt()) {
15237 // Allow casts of address-of-label differences if they are no-ops
15238 // or narrowing. (The narrowing case isn't actually guaranteed to
15239 // be constant-evaluatable except in some narrow cases which are hard
15240 // to detect here. We let it through on the assumption the user knows
15241 // what they are doing.)
15242 if (Result.isAddrLabelDiff())
15243 return Info.Ctx.getTypeSize(T: DestType) <= Info.Ctx.getTypeSize(T: SrcType);
15244 // Only allow casts of lvalues if they are lossless.
15245 return Info.Ctx.getTypeSize(T: DestType) == Info.Ctx.getTypeSize(T: SrcType);
15246 }
15247
15248 if (Info.Ctx.getLangOpts().CPlusPlus && DestType->isEnumeralType()) {
15249 const EnumType *ET = dyn_cast<EnumType>(Val: DestType.getCanonicalType());
15250 const EnumDecl *ED = ET->getDecl();
15251 // Check that the value is within the range of the enumeration values.
15252 //
15253 // This corressponds to [expr.static.cast]p10 which says:
15254 // A value of integral or enumeration type can be explicitly converted
15255 // to a complete enumeration type ... If the enumeration type does not
15256 // have a fixed underlying type, the value is unchanged if the original
15257 // value is within the range of the enumeration values ([dcl.enum]), and
15258 // otherwise, the behavior is undefined.
15259 //
15260 // This was resolved as part of DR2338 which has CD5 status.
15261 if (!ED->isFixed()) {
15262 llvm::APInt Min;
15263 llvm::APInt Max;
15264
15265 ED->getValueRange(Max, Min);
15266 --Max;
15267
15268 if (ED->getNumNegativeBits() &&
15269 (Max.slt(RHS: Result.getInt().getSExtValue()) ||
15270 Min.sgt(RHS: Result.getInt().getSExtValue())))
15271 Info.CCEDiag(E, DiagId: diag::note_constexpr_unscoped_enum_out_of_range)
15272 << llvm::toString(I: Result.getInt(), Radix: 10) << Min.getSExtValue()
15273 << Max.getSExtValue() << ED;
15274 else if (!ED->getNumNegativeBits() &&
15275 Max.ult(RHS: Result.getInt().getZExtValue()))
15276 Info.CCEDiag(E, DiagId: diag::note_constexpr_unscoped_enum_out_of_range)
15277 << llvm::toString(I: Result.getInt(), Radix: 10) << Min.getZExtValue()
15278 << Max.getZExtValue() << ED;
15279 }
15280 }
15281
15282 return Success(SI: HandleIntToIntCast(Info, E, DestType, SrcType,
15283 Value: Result.getInt()), E);
15284 }
15285
15286 case CK_PointerToIntegral: {
15287 CCEDiag(E, D: diag::note_constexpr_invalid_cast)
15288 << diag::ConstexprInvalidCastKind::ThisConversionOrReinterpret
15289 << Info.Ctx.getLangOpts().CPlusPlus << E->getSourceRange();
15290
15291 LValue LV;
15292 if (!EvaluatePointer(E: SubExpr, Result&: LV, Info))
15293 return false;
15294
15295 if (LV.getLValueBase()) {
15296 // Only allow based lvalue casts if they are lossless.
15297 // FIXME: Allow a larger integer size than the pointer size, and allow
15298 // narrowing back down to pointer width in subsequent integral casts.
15299 // FIXME: Check integer type's active bits, not its type size.
15300 if (Info.Ctx.getTypeSize(T: DestType) != Info.Ctx.getTypeSize(T: SrcType))
15301 return Error(E);
15302
15303 LV.Designator.setInvalid();
15304 LV.moveInto(V&: Result);
15305 return true;
15306 }
15307
15308 APSInt AsInt;
15309 APValue V;
15310 LV.moveInto(V);
15311 if (!V.toIntegralConstant(Result&: AsInt, SrcTy: SrcType, Ctx: Info.Ctx))
15312 llvm_unreachable("Can't cast this!");
15313
15314 return Success(SI: HandleIntToIntCast(Info, E, DestType, SrcType, Value: AsInt), E);
15315 }
15316
15317 case CK_IntegralComplexToReal: {
15318 ComplexValue C;
15319 if (!EvaluateComplex(E: SubExpr, Res&: C, Info))
15320 return false;
15321 return Success(SI: C.getComplexIntReal(), E);
15322 }
15323
15324 case CK_FloatingToIntegral: {
15325 APFloat F(0.0);
15326 if (!EvaluateFloat(E: SubExpr, Result&: F, Info))
15327 return false;
15328
15329 APSInt Value;
15330 if (!HandleFloatToIntCast(Info, E, SrcType, Value: F, DestType, Result&: Value))
15331 return false;
15332 return Success(SI: Value, E);
15333 }
15334 case CK_HLSLVectorTruncation: {
15335 APValue Val;
15336 if (!EvaluateVector(E: SubExpr, Result&: Val, Info))
15337 return Error(E);
15338 return Success(V: Val.getVectorElt(I: 0), E);
15339 }
15340 }
15341
15342 llvm_unreachable("unknown cast resulting in integral value");
15343}
15344
15345bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
15346 if (E->getSubExpr()->getType()->isAnyComplexType()) {
15347 ComplexValue LV;
15348 if (!EvaluateComplex(E: E->getSubExpr(), Res&: LV, Info))
15349 return false;
15350 if (!LV.isComplexInt())
15351 return Error(E);
15352 return Success(SI: LV.getComplexIntReal(), E);
15353 }
15354
15355 return Visit(S: E->getSubExpr());
15356}
15357
15358bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
15359 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
15360 ComplexValue LV;
15361 if (!EvaluateComplex(E: E->getSubExpr(), Res&: LV, Info))
15362 return false;
15363 if (!LV.isComplexInt())
15364 return Error(E);
15365 return Success(SI: LV.getComplexIntImag(), E);
15366 }
15367
15368 VisitIgnoredValue(E: E->getSubExpr());
15369 return Success(Value: 0, E);
15370}
15371
15372bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
15373 return Success(Value: E->getPackLength(), E);
15374}
15375
15376bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
15377 return Success(Value: E->getValue(), E);
15378}
15379
15380bool IntExprEvaluator::VisitConceptSpecializationExpr(
15381 const ConceptSpecializationExpr *E) {
15382 return Success(Value: E->isSatisfied(), E);
15383}
15384
15385bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
15386 return Success(Value: E->isSatisfied(), E);
15387}
15388
15389bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
15390 switch (E->getOpcode()) {
15391 default:
15392 // Invalid unary operators
15393 return Error(E);
15394 case UO_Plus:
15395 // The result is just the value.
15396 return Visit(S: E->getSubExpr());
15397 case UO_Minus: {
15398 if (!Visit(S: E->getSubExpr())) return false;
15399 if (!Result.isFixedPoint())
15400 return Error(E);
15401 bool Overflowed;
15402 APFixedPoint Negated = Result.getFixedPoint().negate(Overflow: &Overflowed);
15403 if (Overflowed && !HandleOverflow(Info, E, SrcValue: Negated, DestType: E->getType()))
15404 return false;
15405 return Success(V: Negated, E);
15406 }
15407 case UO_LNot: {
15408 bool bres;
15409 if (!EvaluateAsBooleanCondition(E: E->getSubExpr(), Result&: bres, Info))
15410 return false;
15411 return Success(Value: !bres, E);
15412 }
15413 }
15414}
15415
15416bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
15417 const Expr *SubExpr = E->getSubExpr();
15418 QualType DestType = E->getType();
15419 assert(DestType->isFixedPointType() &&
15420 "Expected destination type to be a fixed point type");
15421 auto DestFXSema = Info.Ctx.getFixedPointSemantics(Ty: DestType);
15422
15423 switch (E->getCastKind()) {
15424 case CK_FixedPointCast: {
15425 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(Ty: SubExpr->getType()));
15426 if (!EvaluateFixedPoint(E: SubExpr, Result&: Src, Info))
15427 return false;
15428 bool Overflowed;
15429 APFixedPoint Result = Src.convert(DstSema: DestFXSema, Overflow: &Overflowed);
15430 if (Overflowed) {
15431 if (Info.checkingForUndefinedBehavior())
15432 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
15433 DiagID: diag::warn_fixedpoint_constant_overflow)
15434 << Result.toString() << E->getType();
15435 if (!HandleOverflow(Info, E, SrcValue: Result, DestType: E->getType()))
15436 return false;
15437 }
15438 return Success(V: Result, E);
15439 }
15440 case CK_IntegralToFixedPoint: {
15441 APSInt Src;
15442 if (!EvaluateInteger(E: SubExpr, Result&: Src, Info))
15443 return false;
15444
15445 bool Overflowed;
15446 APFixedPoint IntResult = APFixedPoint::getFromIntValue(
15447 Value: Src, DstFXSema: Info.Ctx.getFixedPointSemantics(Ty: DestType), Overflow: &Overflowed);
15448
15449 if (Overflowed) {
15450 if (Info.checkingForUndefinedBehavior())
15451 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
15452 DiagID: diag::warn_fixedpoint_constant_overflow)
15453 << IntResult.toString() << E->getType();
15454 if (!HandleOverflow(Info, E, SrcValue: IntResult, DestType: E->getType()))
15455 return false;
15456 }
15457
15458 return Success(V: IntResult, E);
15459 }
15460 case CK_FloatingToFixedPoint: {
15461 APFloat Src(0.0);
15462 if (!EvaluateFloat(E: SubExpr, Result&: Src, Info))
15463 return false;
15464
15465 bool Overflowed;
15466 APFixedPoint Result = APFixedPoint::getFromFloatValue(
15467 Value: Src, DstFXSema: Info.Ctx.getFixedPointSemantics(Ty: DestType), Overflow: &Overflowed);
15468
15469 if (Overflowed) {
15470 if (Info.checkingForUndefinedBehavior())
15471 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
15472 DiagID: diag::warn_fixedpoint_constant_overflow)
15473 << Result.toString() << E->getType();
15474 if (!HandleOverflow(Info, E, SrcValue: Result, DestType: E->getType()))
15475 return false;
15476 }
15477
15478 return Success(V: Result, E);
15479 }
15480 case CK_NoOp:
15481 case CK_LValueToRValue:
15482 return ExprEvaluatorBaseTy::VisitCastExpr(E);
15483 default:
15484 return Error(E);
15485 }
15486}
15487
15488bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
15489 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
15490 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
15491
15492 const Expr *LHS = E->getLHS();
15493 const Expr *RHS = E->getRHS();
15494 FixedPointSemantics ResultFXSema =
15495 Info.Ctx.getFixedPointSemantics(Ty: E->getType());
15496
15497 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(Ty: LHS->getType()));
15498 if (!EvaluateFixedPointOrInteger(E: LHS, Result&: LHSFX, Info))
15499 return false;
15500 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(Ty: RHS->getType()));
15501 if (!EvaluateFixedPointOrInteger(E: RHS, Result&: RHSFX, Info))
15502 return false;
15503
15504 bool OpOverflow = false, ConversionOverflow = false;
15505 APFixedPoint Result(LHSFX.getSemantics());
15506 switch (E->getOpcode()) {
15507 case BO_Add: {
15508 Result = LHSFX.add(Other: RHSFX, Overflow: &OpOverflow)
15509 .convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
15510 break;
15511 }
15512 case BO_Sub: {
15513 Result = LHSFX.sub(Other: RHSFX, Overflow: &OpOverflow)
15514 .convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
15515 break;
15516 }
15517 case BO_Mul: {
15518 Result = LHSFX.mul(Other: RHSFX, Overflow: &OpOverflow)
15519 .convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
15520 break;
15521 }
15522 case BO_Div: {
15523 if (RHSFX.getValue() == 0) {
15524 Info.FFDiag(E, DiagId: diag::note_expr_divide_by_zero);
15525 return false;
15526 }
15527 Result = LHSFX.div(Other: RHSFX, Overflow: &OpOverflow)
15528 .convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
15529 break;
15530 }
15531 case BO_Shl:
15532 case BO_Shr: {
15533 FixedPointSemantics LHSSema = LHSFX.getSemantics();
15534 llvm::APSInt RHSVal = RHSFX.getValue();
15535
15536 unsigned ShiftBW =
15537 LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding();
15538 unsigned Amt = RHSVal.getLimitedValue(Limit: ShiftBW - 1);
15539 // Embedded-C 4.1.6.2.2:
15540 // The right operand must be nonnegative and less than the total number
15541 // of (nonpadding) bits of the fixed-point operand ...
15542 if (RHSVal.isNegative())
15543 Info.CCEDiag(E, DiagId: diag::note_constexpr_negative_shift) << RHSVal;
15544 else if (Amt != RHSVal)
15545 Info.CCEDiag(E, DiagId: diag::note_constexpr_large_shift)
15546 << RHSVal << E->getType() << ShiftBW;
15547
15548 if (E->getOpcode() == BO_Shl)
15549 Result = LHSFX.shl(Amt, Overflow: &OpOverflow);
15550 else
15551 Result = LHSFX.shr(Amt, Overflow: &OpOverflow);
15552 break;
15553 }
15554 default:
15555 return false;
15556 }
15557 if (OpOverflow || ConversionOverflow) {
15558 if (Info.checkingForUndefinedBehavior())
15559 Info.Ctx.getDiagnostics().Report(Loc: E->getExprLoc(),
15560 DiagID: diag::warn_fixedpoint_constant_overflow)
15561 << Result.toString() << E->getType();
15562 if (!HandleOverflow(Info, E, SrcValue: Result, DestType: E->getType()))
15563 return false;
15564 }
15565 return Success(V: Result, E);
15566}
15567
15568//===----------------------------------------------------------------------===//
15569// Float Evaluation
15570//===----------------------------------------------------------------------===//
15571
15572namespace {
15573class FloatExprEvaluator
15574 : public ExprEvaluatorBase<FloatExprEvaluator> {
15575 APFloat &Result;
15576public:
15577 FloatExprEvaluator(EvalInfo &info, APFloat &result)
15578 : ExprEvaluatorBaseTy(info), Result(result) {}
15579
15580 bool Success(const APValue &V, const Expr *e) {
15581 Result = V.getFloat();
15582 return true;
15583 }
15584
15585 bool ZeroInitialization(const Expr *E) {
15586 Result = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: E->getType()));
15587 return true;
15588 }
15589
15590 bool VisitCallExpr(const CallExpr *E);
15591
15592 bool VisitUnaryOperator(const UnaryOperator *E);
15593 bool VisitBinaryOperator(const BinaryOperator *E);
15594 bool VisitFloatingLiteral(const FloatingLiteral *E);
15595 bool VisitCastExpr(const CastExpr *E);
15596
15597 bool VisitUnaryReal(const UnaryOperator *E);
15598 bool VisitUnaryImag(const UnaryOperator *E);
15599
15600 // FIXME: Missing: array subscript of vector, member of vector
15601};
15602} // end anonymous namespace
15603
15604static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
15605 assert(!E->isValueDependent());
15606 assert(E->isPRValue() && E->getType()->isRealFloatingType());
15607 return FloatExprEvaluator(Info, Result).Visit(S: E);
15608}
15609
15610static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
15611 QualType ResultTy,
15612 const Expr *Arg,
15613 bool SNaN,
15614 llvm::APFloat &Result) {
15615 const StringLiteral *S = dyn_cast<StringLiteral>(Val: Arg->IgnoreParenCasts());
15616 if (!S) return false;
15617
15618 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(T: ResultTy);
15619
15620 llvm::APInt fill;
15621
15622 // Treat empty strings as if they were zero.
15623 if (S->getString().empty())
15624 fill = llvm::APInt(32, 0);
15625 else if (S->getString().getAsInteger(Radix: 0, Result&: fill))
15626 return false;
15627
15628 if (Context.getTargetInfo().isNan2008()) {
15629 if (SNaN)
15630 Result = llvm::APFloat::getSNaN(Sem, Negative: false, payload: &fill);
15631 else
15632 Result = llvm::APFloat::getQNaN(Sem, Negative: false, payload: &fill);
15633 } else {
15634 // Prior to IEEE 754-2008, architectures were allowed to choose whether
15635 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
15636 // a different encoding to what became a standard in 2008, and for pre-
15637 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
15638 // sNaN. This is now known as "legacy NaN" encoding.
15639 if (SNaN)
15640 Result = llvm::APFloat::getQNaN(Sem, Negative: false, payload: &fill);
15641 else
15642 Result = llvm::APFloat::getSNaN(Sem, Negative: false, payload: &fill);
15643 }
15644
15645 return true;
15646}
15647
15648bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
15649 if (!IsConstantEvaluatedBuiltinCall(E))
15650 return ExprEvaluatorBaseTy::VisitCallExpr(E);
15651
15652 switch (E->getBuiltinCallee()) {
15653 default:
15654 return false;
15655
15656 case Builtin::BI__builtin_huge_val:
15657 case Builtin::BI__builtin_huge_valf:
15658 case Builtin::BI__builtin_huge_vall:
15659 case Builtin::BI__builtin_huge_valf16:
15660 case Builtin::BI__builtin_huge_valf128:
15661 case Builtin::BI__builtin_inf:
15662 case Builtin::BI__builtin_inff:
15663 case Builtin::BI__builtin_infl:
15664 case Builtin::BI__builtin_inff16:
15665 case Builtin::BI__builtin_inff128: {
15666 const llvm::fltSemantics &Sem =
15667 Info.Ctx.getFloatTypeSemantics(T: E->getType());
15668 Result = llvm::APFloat::getInf(Sem);
15669 return true;
15670 }
15671
15672 case Builtin::BI__builtin_nans:
15673 case Builtin::BI__builtin_nansf:
15674 case Builtin::BI__builtin_nansl:
15675 case Builtin::BI__builtin_nansf16:
15676 case Builtin::BI__builtin_nansf128:
15677 if (!TryEvaluateBuiltinNaN(Context: Info.Ctx, ResultTy: E->getType(), Arg: E->getArg(Arg: 0),
15678 SNaN: true, Result))
15679 return Error(E);
15680 return true;
15681
15682 case Builtin::BI__builtin_nan:
15683 case Builtin::BI__builtin_nanf:
15684 case Builtin::BI__builtin_nanl:
15685 case Builtin::BI__builtin_nanf16:
15686 case Builtin::BI__builtin_nanf128:
15687 // If this is __builtin_nan() turn this into a nan, otherwise we
15688 // can't constant fold it.
15689 if (!TryEvaluateBuiltinNaN(Context: Info.Ctx, ResultTy: E->getType(), Arg: E->getArg(Arg: 0),
15690 SNaN: false, Result))
15691 return Error(E);
15692 return true;
15693
15694 case Builtin::BI__builtin_fabs:
15695 case Builtin::BI__builtin_fabsf:
15696 case Builtin::BI__builtin_fabsl:
15697 case Builtin::BI__builtin_fabsf128:
15698 // The C standard says "fabs raises no floating-point exceptions,
15699 // even if x is a signaling NaN. The returned value is independent of
15700 // the current rounding direction mode." Therefore constant folding can
15701 // proceed without regard to the floating point settings.
15702 // Reference, WG14 N2478 F.10.4.3
15703 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info))
15704 return false;
15705
15706 if (Result.isNegative())
15707 Result.changeSign();
15708 return true;
15709
15710 case Builtin::BI__arithmetic_fence:
15711 return EvaluateFloat(E: E->getArg(Arg: 0), Result, Info);
15712
15713 // FIXME: Builtin::BI__builtin_powi
15714 // FIXME: Builtin::BI__builtin_powif
15715 // FIXME: Builtin::BI__builtin_powil
15716
15717 case Builtin::BI__builtin_copysign:
15718 case Builtin::BI__builtin_copysignf:
15719 case Builtin::BI__builtin_copysignl:
15720 case Builtin::BI__builtin_copysignf128: {
15721 APFloat RHS(0.);
15722 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
15723 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
15724 return false;
15725 Result.copySign(RHS);
15726 return true;
15727 }
15728
15729 case Builtin::BI__builtin_fmax:
15730 case Builtin::BI__builtin_fmaxf:
15731 case Builtin::BI__builtin_fmaxl:
15732 case Builtin::BI__builtin_fmaxf16:
15733 case Builtin::BI__builtin_fmaxf128: {
15734 APFloat RHS(0.);
15735 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
15736 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
15737 return false;
15738 Result = maxnum(A: Result, B: RHS);
15739 return true;
15740 }
15741
15742 case Builtin::BI__builtin_fmin:
15743 case Builtin::BI__builtin_fminf:
15744 case Builtin::BI__builtin_fminl:
15745 case Builtin::BI__builtin_fminf16:
15746 case Builtin::BI__builtin_fminf128: {
15747 APFloat RHS(0.);
15748 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
15749 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
15750 return false;
15751 Result = minnum(A: Result, B: RHS);
15752 return true;
15753 }
15754
15755 case Builtin::BI__builtin_fmaximum_num:
15756 case Builtin::BI__builtin_fmaximum_numf:
15757 case Builtin::BI__builtin_fmaximum_numl:
15758 case Builtin::BI__builtin_fmaximum_numf16:
15759 case Builtin::BI__builtin_fmaximum_numf128: {
15760 APFloat RHS(0.);
15761 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
15762 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
15763 return false;
15764 Result = maximumnum(A: Result, B: RHS);
15765 return true;
15766 }
15767
15768 case Builtin::BI__builtin_fminimum_num:
15769 case Builtin::BI__builtin_fminimum_numf:
15770 case Builtin::BI__builtin_fminimum_numl:
15771 case Builtin::BI__builtin_fminimum_numf16:
15772 case Builtin::BI__builtin_fminimum_numf128: {
15773 APFloat RHS(0.);
15774 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
15775 !EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
15776 return false;
15777 Result = minimumnum(A: Result, B: RHS);
15778 return true;
15779 }
15780 }
15781}
15782
15783bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
15784 if (E->getSubExpr()->getType()->isAnyComplexType()) {
15785 ComplexValue CV;
15786 if (!EvaluateComplex(E: E->getSubExpr(), Res&: CV, Info))
15787 return false;
15788 Result = CV.FloatReal;
15789 return true;
15790 }
15791
15792 return Visit(S: E->getSubExpr());
15793}
15794
15795bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
15796 if (E->getSubExpr()->getType()->isAnyComplexType()) {
15797 ComplexValue CV;
15798 if (!EvaluateComplex(E: E->getSubExpr(), Res&: CV, Info))
15799 return false;
15800 Result = CV.FloatImag;
15801 return true;
15802 }
15803
15804 VisitIgnoredValue(E: E->getSubExpr());
15805 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(T: E->getType());
15806 Result = llvm::APFloat::getZero(Sem);
15807 return true;
15808}
15809
15810bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
15811 switch (E->getOpcode()) {
15812 default: return Error(E);
15813 case UO_Plus:
15814 return EvaluateFloat(E: E->getSubExpr(), Result, Info);
15815 case UO_Minus:
15816 // In C standard, WG14 N2478 F.3 p4
15817 // "the unary - raises no floating point exceptions,
15818 // even if the operand is signalling."
15819 if (!EvaluateFloat(E: E->getSubExpr(), Result, Info))
15820 return false;
15821 Result.changeSign();
15822 return true;
15823 }
15824}
15825
15826bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
15827 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
15828 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
15829
15830 APFloat RHS(0.0);
15831 bool LHSOK = EvaluateFloat(E: E->getLHS(), Result, Info);
15832 if (!LHSOK && !Info.noteFailure())
15833 return false;
15834 return EvaluateFloat(E: E->getRHS(), Result&: RHS, Info) && LHSOK &&
15835 handleFloatFloatBinOp(Info, E, LHS&: Result, Opcode: E->getOpcode(), RHS);
15836}
15837
15838bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
15839 Result = E->getValue();
15840 return true;
15841}
15842
15843bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
15844 const Expr* SubExpr = E->getSubExpr();
15845
15846 switch (E->getCastKind()) {
15847 default:
15848 return ExprEvaluatorBaseTy::VisitCastExpr(E);
15849
15850 case CK_IntegralToFloating: {
15851 APSInt IntResult;
15852 const FPOptions FPO = E->getFPFeaturesInEffect(
15853 LO: Info.Ctx.getLangOpts());
15854 return EvaluateInteger(E: SubExpr, Result&: IntResult, Info) &&
15855 HandleIntToFloatCast(Info, E, FPO, SrcType: SubExpr->getType(),
15856 Value: IntResult, DestType: E->getType(), Result);
15857 }
15858
15859 case CK_FixedPointToFloating: {
15860 APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(Ty: SubExpr->getType()));
15861 if (!EvaluateFixedPoint(E: SubExpr, Result&: FixResult, Info))
15862 return false;
15863 Result =
15864 FixResult.convertToFloat(FloatSema: Info.Ctx.getFloatTypeSemantics(T: E->getType()));
15865 return true;
15866 }
15867
15868 case CK_FloatingCast: {
15869 if (!Visit(S: SubExpr))
15870 return false;
15871 return HandleFloatToFloatCast(Info, E, SrcType: SubExpr->getType(), DestType: E->getType(),
15872 Result);
15873 }
15874
15875 case CK_FloatingComplexToReal: {
15876 ComplexValue V;
15877 if (!EvaluateComplex(E: SubExpr, Res&: V, Info))
15878 return false;
15879 Result = V.getComplexFloatReal();
15880 return true;
15881 }
15882 case CK_HLSLVectorTruncation: {
15883 APValue Val;
15884 if (!EvaluateVector(E: SubExpr, Result&: Val, Info))
15885 return Error(E);
15886 return Success(V: Val.getVectorElt(I: 0), e: E);
15887 }
15888 }
15889}
15890
15891//===----------------------------------------------------------------------===//
15892// Complex Evaluation (for float and integer)
15893//===----------------------------------------------------------------------===//
15894
15895namespace {
15896class ComplexExprEvaluator
15897 : public ExprEvaluatorBase<ComplexExprEvaluator> {
15898 ComplexValue &Result;
15899
15900public:
15901 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
15902 : ExprEvaluatorBaseTy(info), Result(Result) {}
15903
15904 bool Success(const APValue &V, const Expr *e) {
15905 Result.setFrom(V);
15906 return true;
15907 }
15908
15909 bool ZeroInitialization(const Expr *E);
15910
15911 //===--------------------------------------------------------------------===//
15912 // Visitor Methods
15913 //===--------------------------------------------------------------------===//
15914
15915 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
15916 bool VisitCastExpr(const CastExpr *E);
15917 bool VisitBinaryOperator(const BinaryOperator *E);
15918 bool VisitUnaryOperator(const UnaryOperator *E);
15919 bool VisitInitListExpr(const InitListExpr *E);
15920 bool VisitCallExpr(const CallExpr *E);
15921};
15922} // end anonymous namespace
15923
15924static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
15925 EvalInfo &Info) {
15926 assert(!E->isValueDependent());
15927 assert(E->isPRValue() && E->getType()->isAnyComplexType());
15928 return ComplexExprEvaluator(Info, Result).Visit(S: E);
15929}
15930
15931bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
15932 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
15933 if (ElemTy->isRealFloatingType()) {
15934 Result.makeComplexFloat();
15935 APFloat Zero = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: ElemTy));
15936 Result.FloatReal = Zero;
15937 Result.FloatImag = Zero;
15938 } else {
15939 Result.makeComplexInt();
15940 APSInt Zero = Info.Ctx.MakeIntValue(Value: 0, Type: ElemTy);
15941 Result.IntReal = Zero;
15942 Result.IntImag = Zero;
15943 }
15944 return true;
15945}
15946
15947bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
15948 const Expr* SubExpr = E->getSubExpr();
15949
15950 if (SubExpr->getType()->isRealFloatingType()) {
15951 Result.makeComplexFloat();
15952 APFloat &Imag = Result.FloatImag;
15953 if (!EvaluateFloat(E: SubExpr, Result&: Imag, Info))
15954 return false;
15955
15956 Result.FloatReal = APFloat(Imag.getSemantics());
15957 return true;
15958 } else {
15959 assert(SubExpr->getType()->isIntegerType() &&
15960 "Unexpected imaginary literal.");
15961
15962 Result.makeComplexInt();
15963 APSInt &Imag = Result.IntImag;
15964 if (!EvaluateInteger(E: SubExpr, Result&: Imag, Info))
15965 return false;
15966
15967 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
15968 return true;
15969 }
15970}
15971
15972bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
15973
15974 switch (E->getCastKind()) {
15975 case CK_BitCast:
15976 case CK_BaseToDerived:
15977 case CK_DerivedToBase:
15978 case CK_UncheckedDerivedToBase:
15979 case CK_Dynamic:
15980 case CK_ToUnion:
15981 case CK_ArrayToPointerDecay:
15982 case CK_FunctionToPointerDecay:
15983 case CK_NullToPointer:
15984 case CK_NullToMemberPointer:
15985 case CK_BaseToDerivedMemberPointer:
15986 case CK_DerivedToBaseMemberPointer:
15987 case CK_MemberPointerToBoolean:
15988 case CK_ReinterpretMemberPointer:
15989 case CK_ConstructorConversion:
15990 case CK_IntegralToPointer:
15991 case CK_PointerToIntegral:
15992 case CK_PointerToBoolean:
15993 case CK_ToVoid:
15994 case CK_VectorSplat:
15995 case CK_IntegralCast:
15996 case CK_BooleanToSignedIntegral:
15997 case CK_IntegralToBoolean:
15998 case CK_IntegralToFloating:
15999 case CK_FloatingToIntegral:
16000 case CK_FloatingToBoolean:
16001 case CK_FloatingCast:
16002 case CK_CPointerToObjCPointerCast:
16003 case CK_BlockPointerToObjCPointerCast:
16004 case CK_AnyPointerToBlockPointerCast:
16005 case CK_ObjCObjectLValueCast:
16006 case CK_FloatingComplexToReal:
16007 case CK_FloatingComplexToBoolean:
16008 case CK_IntegralComplexToReal:
16009 case CK_IntegralComplexToBoolean:
16010 case CK_ARCProduceObject:
16011 case CK_ARCConsumeObject:
16012 case CK_ARCReclaimReturnedObject:
16013 case CK_ARCExtendBlockObject:
16014 case CK_CopyAndAutoreleaseBlockObject:
16015 case CK_BuiltinFnToFnPtr:
16016 case CK_ZeroToOCLOpaqueType:
16017 case CK_NonAtomicToAtomic:
16018 case CK_AddressSpaceConversion:
16019 case CK_IntToOCLSampler:
16020 case CK_FloatingToFixedPoint:
16021 case CK_FixedPointToFloating:
16022 case CK_FixedPointCast:
16023 case CK_FixedPointToBoolean:
16024 case CK_FixedPointToIntegral:
16025 case CK_IntegralToFixedPoint:
16026 case CK_MatrixCast:
16027 case CK_HLSLVectorTruncation:
16028 case CK_HLSLElementwiseCast:
16029 case CK_HLSLAggregateSplatCast:
16030 llvm_unreachable("invalid cast kind for complex value");
16031
16032 case CK_LValueToRValue:
16033 case CK_AtomicToNonAtomic:
16034 case CK_NoOp:
16035 case CK_LValueToRValueBitCast:
16036 case CK_HLSLArrayRValue:
16037 return ExprEvaluatorBaseTy::VisitCastExpr(E);
16038
16039 case CK_Dependent:
16040 case CK_LValueBitCast:
16041 case CK_UserDefinedConversion:
16042 return Error(E);
16043
16044 case CK_FloatingRealToComplex: {
16045 APFloat &Real = Result.FloatReal;
16046 if (!EvaluateFloat(E: E->getSubExpr(), Result&: Real, Info))
16047 return false;
16048
16049 Result.makeComplexFloat();
16050 Result.FloatImag = APFloat(Real.getSemantics());
16051 return true;
16052 }
16053
16054 case CK_FloatingComplexCast: {
16055 if (!Visit(S: E->getSubExpr()))
16056 return false;
16057
16058 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
16059 QualType From
16060 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
16061
16062 return HandleFloatToFloatCast(Info, E, SrcType: From, DestType: To, Result&: Result.FloatReal) &&
16063 HandleFloatToFloatCast(Info, E, SrcType: From, DestType: To, Result&: Result.FloatImag);
16064 }
16065
16066 case CK_FloatingComplexToIntegralComplex: {
16067 if (!Visit(S: E->getSubExpr()))
16068 return false;
16069
16070 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
16071 QualType From
16072 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
16073 Result.makeComplexInt();
16074 return HandleFloatToIntCast(Info, E, SrcType: From, Value: Result.FloatReal,
16075 DestType: To, Result&: Result.IntReal) &&
16076 HandleFloatToIntCast(Info, E, SrcType: From, Value: Result.FloatImag,
16077 DestType: To, Result&: Result.IntImag);
16078 }
16079
16080 case CK_IntegralRealToComplex: {
16081 APSInt &Real = Result.IntReal;
16082 if (!EvaluateInteger(E: E->getSubExpr(), Result&: Real, Info))
16083 return false;
16084
16085 Result.makeComplexInt();
16086 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
16087 return true;
16088 }
16089
16090 case CK_IntegralComplexCast: {
16091 if (!Visit(S: E->getSubExpr()))
16092 return false;
16093
16094 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
16095 QualType From
16096 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
16097
16098 Result.IntReal = HandleIntToIntCast(Info, E, DestType: To, SrcType: From, Value: Result.IntReal);
16099 Result.IntImag = HandleIntToIntCast(Info, E, DestType: To, SrcType: From, Value: Result.IntImag);
16100 return true;
16101 }
16102
16103 case CK_IntegralComplexToFloatingComplex: {
16104 if (!Visit(S: E->getSubExpr()))
16105 return false;
16106
16107 const FPOptions FPO = E->getFPFeaturesInEffect(
16108 LO: Info.Ctx.getLangOpts());
16109 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
16110 QualType From
16111 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
16112 Result.makeComplexFloat();
16113 return HandleIntToFloatCast(Info, E, FPO, SrcType: From, Value: Result.IntReal,
16114 DestType: To, Result&: Result.FloatReal) &&
16115 HandleIntToFloatCast(Info, E, FPO, SrcType: From, Value: Result.IntImag,
16116 DestType: To, Result&: Result.FloatImag);
16117 }
16118 }
16119
16120 llvm_unreachable("unknown cast resulting in complex value");
16121}
16122
16123void HandleComplexComplexMul(APFloat A, APFloat B, APFloat C, APFloat D,
16124 APFloat &ResR, APFloat &ResI) {
16125 // This is an implementation of complex multiplication according to the
16126 // constraints laid out in C11 Annex G. The implementation uses the
16127 // following naming scheme:
16128 // (a + ib) * (c + id)
16129
16130 APFloat AC = A * C;
16131 APFloat BD = B * D;
16132 APFloat AD = A * D;
16133 APFloat BC = B * C;
16134 ResR = AC - BD;
16135 ResI = AD + BC;
16136 if (ResR.isNaN() && ResI.isNaN()) {
16137 bool Recalc = false;
16138 if (A.isInfinity() || B.isInfinity()) {
16139 A = APFloat::copySign(Value: APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0),
16140 Sign: A);
16141 B = APFloat::copySign(Value: APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0),
16142 Sign: B);
16143 if (C.isNaN())
16144 C = APFloat::copySign(Value: APFloat(C.getSemantics()), Sign: C);
16145 if (D.isNaN())
16146 D = APFloat::copySign(Value: APFloat(D.getSemantics()), Sign: D);
16147 Recalc = true;
16148 }
16149 if (C.isInfinity() || D.isInfinity()) {
16150 C = APFloat::copySign(Value: APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0),
16151 Sign: C);
16152 D = APFloat::copySign(Value: APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0),
16153 Sign: D);
16154 if (A.isNaN())
16155 A = APFloat::copySign(Value: APFloat(A.getSemantics()), Sign: A);
16156 if (B.isNaN())
16157 B = APFloat::copySign(Value: APFloat(B.getSemantics()), Sign: B);
16158 Recalc = true;
16159 }
16160 if (!Recalc && (AC.isInfinity() || BD.isInfinity() || AD.isInfinity() ||
16161 BC.isInfinity())) {
16162 if (A.isNaN())
16163 A = APFloat::copySign(Value: APFloat(A.getSemantics()), Sign: A);
16164 if (B.isNaN())
16165 B = APFloat::copySign(Value: APFloat(B.getSemantics()), Sign: B);
16166 if (C.isNaN())
16167 C = APFloat::copySign(Value: APFloat(C.getSemantics()), Sign: C);
16168 if (D.isNaN())
16169 D = APFloat::copySign(Value: APFloat(D.getSemantics()), Sign: D);
16170 Recalc = true;
16171 }
16172 if (Recalc) {
16173 ResR = APFloat::getInf(Sem: A.getSemantics()) * (A * C - B * D);
16174 ResI = APFloat::getInf(Sem: A.getSemantics()) * (A * D + B * C);
16175 }
16176 }
16177}
16178
16179void HandleComplexComplexDiv(APFloat A, APFloat B, APFloat C, APFloat D,
16180 APFloat &ResR, APFloat &ResI) {
16181 // This is an implementation of complex division according to the
16182 // constraints laid out in C11 Annex G. The implementation uses the
16183 // following naming scheme:
16184 // (a + ib) / (c + id)
16185
16186 int DenomLogB = 0;
16187 APFloat MaxCD = maxnum(A: abs(X: C), B: abs(X: D));
16188 if (MaxCD.isFinite()) {
16189 DenomLogB = ilogb(Arg: MaxCD);
16190 C = scalbn(X: C, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
16191 D = scalbn(X: D, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
16192 }
16193 APFloat Denom = C * C + D * D;
16194 ResR =
16195 scalbn(X: (A * C + B * D) / Denom, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
16196 ResI =
16197 scalbn(X: (B * C - A * D) / Denom, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
16198 if (ResR.isNaN() && ResI.isNaN()) {
16199 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
16200 ResR = APFloat::getInf(Sem: ResR.getSemantics(), Negative: C.isNegative()) * A;
16201 ResI = APFloat::getInf(Sem: ResR.getSemantics(), Negative: C.isNegative()) * B;
16202 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
16203 D.isFinite()) {
16204 A = APFloat::copySign(Value: APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0),
16205 Sign: A);
16206 B = APFloat::copySign(Value: APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0),
16207 Sign: B);
16208 ResR = APFloat::getInf(Sem: ResR.getSemantics()) * (A * C + B * D);
16209 ResI = APFloat::getInf(Sem: ResI.getSemantics()) * (B * C - A * D);
16210 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
16211 C = APFloat::copySign(Value: APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0),
16212 Sign: C);
16213 D = APFloat::copySign(Value: APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0),
16214 Sign: D);
16215 ResR = APFloat::getZero(Sem: ResR.getSemantics()) * (A * C + B * D);
16216 ResI = APFloat::getZero(Sem: ResI.getSemantics()) * (B * C - A * D);
16217 }
16218 }
16219}
16220
16221bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
16222 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
16223 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
16224
16225 // Track whether the LHS or RHS is real at the type system level. When this is
16226 // the case we can simplify our evaluation strategy.
16227 bool LHSReal = false, RHSReal = false;
16228
16229 bool LHSOK;
16230 if (E->getLHS()->getType()->isRealFloatingType()) {
16231 LHSReal = true;
16232 APFloat &Real = Result.FloatReal;
16233 LHSOK = EvaluateFloat(E: E->getLHS(), Result&: Real, Info);
16234 if (LHSOK) {
16235 Result.makeComplexFloat();
16236 Result.FloatImag = APFloat(Real.getSemantics());
16237 }
16238 } else {
16239 LHSOK = Visit(S: E->getLHS());
16240 }
16241 if (!LHSOK && !Info.noteFailure())
16242 return false;
16243
16244 ComplexValue RHS;
16245 if (E->getRHS()->getType()->isRealFloatingType()) {
16246 RHSReal = true;
16247 APFloat &Real = RHS.FloatReal;
16248 if (!EvaluateFloat(E: E->getRHS(), Result&: Real, Info) || !LHSOK)
16249 return false;
16250 RHS.makeComplexFloat();
16251 RHS.FloatImag = APFloat(Real.getSemantics());
16252 } else if (!EvaluateComplex(E: E->getRHS(), Result&: RHS, Info) || !LHSOK)
16253 return false;
16254
16255 assert(!(LHSReal && RHSReal) &&
16256 "Cannot have both operands of a complex operation be real.");
16257 switch (E->getOpcode()) {
16258 default: return Error(E);
16259 case BO_Add:
16260 if (Result.isComplexFloat()) {
16261 Result.getComplexFloatReal().add(RHS: RHS.getComplexFloatReal(),
16262 RM: APFloat::rmNearestTiesToEven);
16263 if (LHSReal)
16264 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
16265 else if (!RHSReal)
16266 Result.getComplexFloatImag().add(RHS: RHS.getComplexFloatImag(),
16267 RM: APFloat::rmNearestTiesToEven);
16268 } else {
16269 Result.getComplexIntReal() += RHS.getComplexIntReal();
16270 Result.getComplexIntImag() += RHS.getComplexIntImag();
16271 }
16272 break;
16273 case BO_Sub:
16274 if (Result.isComplexFloat()) {
16275 Result.getComplexFloatReal().subtract(RHS: RHS.getComplexFloatReal(),
16276 RM: APFloat::rmNearestTiesToEven);
16277 if (LHSReal) {
16278 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
16279 Result.getComplexFloatImag().changeSign();
16280 } else if (!RHSReal) {
16281 Result.getComplexFloatImag().subtract(RHS: RHS.getComplexFloatImag(),
16282 RM: APFloat::rmNearestTiesToEven);
16283 }
16284 } else {
16285 Result.getComplexIntReal() -= RHS.getComplexIntReal();
16286 Result.getComplexIntImag() -= RHS.getComplexIntImag();
16287 }
16288 break;
16289 case BO_Mul:
16290 if (Result.isComplexFloat()) {
16291 // This is an implementation of complex multiplication according to the
16292 // constraints laid out in C11 Annex G. The implementation uses the
16293 // following naming scheme:
16294 // (a + ib) * (c + id)
16295 ComplexValue LHS = Result;
16296 APFloat &A = LHS.getComplexFloatReal();
16297 APFloat &B = LHS.getComplexFloatImag();
16298 APFloat &C = RHS.getComplexFloatReal();
16299 APFloat &D = RHS.getComplexFloatImag();
16300 APFloat &ResR = Result.getComplexFloatReal();
16301 APFloat &ResI = Result.getComplexFloatImag();
16302 if (LHSReal) {
16303 assert(!RHSReal && "Cannot have two real operands for a complex op!");
16304 ResR = A;
16305 ResI = A;
16306 // ResR = A * C;
16307 // ResI = A * D;
16308 if (!handleFloatFloatBinOp(Info, E, LHS&: ResR, Opcode: BO_Mul, RHS: C) ||
16309 !handleFloatFloatBinOp(Info, E, LHS&: ResI, Opcode: BO_Mul, RHS: D))
16310 return false;
16311 } else if (RHSReal) {
16312 // ResR = C * A;
16313 // ResI = C * B;
16314 ResR = C;
16315 ResI = C;
16316 if (!handleFloatFloatBinOp(Info, E, LHS&: ResR, Opcode: BO_Mul, RHS: A) ||
16317 !handleFloatFloatBinOp(Info, E, LHS&: ResI, Opcode: BO_Mul, RHS: B))
16318 return false;
16319 } else {
16320 HandleComplexComplexMul(A, B, C, D, ResR, ResI);
16321 }
16322 } else {
16323 ComplexValue LHS = Result;
16324 Result.getComplexIntReal() =
16325 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
16326 LHS.getComplexIntImag() * RHS.getComplexIntImag());
16327 Result.getComplexIntImag() =
16328 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
16329 LHS.getComplexIntImag() * RHS.getComplexIntReal());
16330 }
16331 break;
16332 case BO_Div:
16333 if (Result.isComplexFloat()) {
16334 // This is an implementation of complex division according to the
16335 // constraints laid out in C11 Annex G. The implementation uses the
16336 // following naming scheme:
16337 // (a + ib) / (c + id)
16338 ComplexValue LHS = Result;
16339 APFloat &A = LHS.getComplexFloatReal();
16340 APFloat &B = LHS.getComplexFloatImag();
16341 APFloat &C = RHS.getComplexFloatReal();
16342 APFloat &D = RHS.getComplexFloatImag();
16343 APFloat &ResR = Result.getComplexFloatReal();
16344 APFloat &ResI = Result.getComplexFloatImag();
16345 if (RHSReal) {
16346 ResR = A;
16347 ResI = B;
16348 // ResR = A / C;
16349 // ResI = B / C;
16350 if (!handleFloatFloatBinOp(Info, E, LHS&: ResR, Opcode: BO_Div, RHS: C) ||
16351 !handleFloatFloatBinOp(Info, E, LHS&: ResI, Opcode: BO_Div, RHS: C))
16352 return false;
16353 } else {
16354 if (LHSReal) {
16355 // No real optimizations we can do here, stub out with zero.
16356 B = APFloat::getZero(Sem: A.getSemantics());
16357 }
16358 HandleComplexComplexDiv(A, B, C, D, ResR, ResI);
16359 }
16360 } else {
16361 ComplexValue LHS = Result;
16362 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
16363 RHS.getComplexIntImag() * RHS.getComplexIntImag();
16364 if (Den.isZero())
16365 return Error(E, D: diag::note_expr_divide_by_zero);
16366
16367 Result.getComplexIntReal() =
16368 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
16369 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
16370 Result.getComplexIntImag() =
16371 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
16372 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
16373 }
16374 break;
16375 }
16376
16377 return true;
16378}
16379
16380bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
16381 // Get the operand value into 'Result'.
16382 if (!Visit(S: E->getSubExpr()))
16383 return false;
16384
16385 switch (E->getOpcode()) {
16386 default:
16387 return Error(E);
16388 case UO_Extension:
16389 return true;
16390 case UO_Plus:
16391 // The result is always just the subexpr.
16392 return true;
16393 case UO_Minus:
16394 if (Result.isComplexFloat()) {
16395 Result.getComplexFloatReal().changeSign();
16396 Result.getComplexFloatImag().changeSign();
16397 }
16398 else {
16399 Result.getComplexIntReal() = -Result.getComplexIntReal();
16400 Result.getComplexIntImag() = -Result.getComplexIntImag();
16401 }
16402 return true;
16403 case UO_Not:
16404 if (Result.isComplexFloat())
16405 Result.getComplexFloatImag().changeSign();
16406 else
16407 Result.getComplexIntImag() = -Result.getComplexIntImag();
16408 return true;
16409 }
16410}
16411
16412bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
16413 if (E->getNumInits() == 2) {
16414 if (E->getType()->isComplexType()) {
16415 Result.makeComplexFloat();
16416 if (!EvaluateFloat(E: E->getInit(Init: 0), Result&: Result.FloatReal, Info))
16417 return false;
16418 if (!EvaluateFloat(E: E->getInit(Init: 1), Result&: Result.FloatImag, Info))
16419 return false;
16420 } else {
16421 Result.makeComplexInt();
16422 if (!EvaluateInteger(E: E->getInit(Init: 0), Result&: Result.IntReal, Info))
16423 return false;
16424 if (!EvaluateInteger(E: E->getInit(Init: 1), Result&: Result.IntImag, Info))
16425 return false;
16426 }
16427 return true;
16428 }
16429 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
16430}
16431
16432bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) {
16433 if (!IsConstantEvaluatedBuiltinCall(E))
16434 return ExprEvaluatorBaseTy::VisitCallExpr(E);
16435
16436 switch (E->getBuiltinCallee()) {
16437 case Builtin::BI__builtin_complex:
16438 Result.makeComplexFloat();
16439 if (!EvaluateFloat(E: E->getArg(Arg: 0), Result&: Result.FloatReal, Info))
16440 return false;
16441 if (!EvaluateFloat(E: E->getArg(Arg: 1), Result&: Result.FloatImag, Info))
16442 return false;
16443 return true;
16444
16445 default:
16446 return false;
16447 }
16448}
16449
16450//===----------------------------------------------------------------------===//
16451// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
16452// implicit conversion.
16453//===----------------------------------------------------------------------===//
16454
16455namespace {
16456class AtomicExprEvaluator :
16457 public ExprEvaluatorBase<AtomicExprEvaluator> {
16458 const LValue *This;
16459 APValue &Result;
16460public:
16461 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
16462 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
16463
16464 bool Success(const APValue &V, const Expr *E) {
16465 Result = V;
16466 return true;
16467 }
16468
16469 bool ZeroInitialization(const Expr *E) {
16470 ImplicitValueInitExpr VIE(
16471 E->getType()->castAs<AtomicType>()->getValueType());
16472 // For atomic-qualified class (and array) types in C++, initialize the
16473 // _Atomic-wrapped subobject directly, in-place.
16474 return This ? EvaluateInPlace(Result, Info, This: *This, E: &VIE)
16475 : Evaluate(Result, Info, E: &VIE);
16476 }
16477
16478 bool VisitCastExpr(const CastExpr *E) {
16479 switch (E->getCastKind()) {
16480 default:
16481 return ExprEvaluatorBaseTy::VisitCastExpr(E);
16482 case CK_NullToPointer:
16483 VisitIgnoredValue(E: E->getSubExpr());
16484 return ZeroInitialization(E);
16485 case CK_NonAtomicToAtomic:
16486 return This ? EvaluateInPlace(Result, Info, This: *This, E: E->getSubExpr())
16487 : Evaluate(Result, Info, E: E->getSubExpr());
16488 }
16489 }
16490};
16491} // end anonymous namespace
16492
16493static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
16494 EvalInfo &Info) {
16495 assert(!E->isValueDependent());
16496 assert(E->isPRValue() && E->getType()->isAtomicType());
16497 return AtomicExprEvaluator(Info, This, Result).Visit(S: E);
16498}
16499
16500//===----------------------------------------------------------------------===//
16501// Void expression evaluation, primarily for a cast to void on the LHS of a
16502// comma operator
16503//===----------------------------------------------------------------------===//
16504
16505namespace {
16506class VoidExprEvaluator
16507 : public ExprEvaluatorBase<VoidExprEvaluator> {
16508public:
16509 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
16510
16511 bool Success(const APValue &V, const Expr *e) { return true; }
16512
16513 bool ZeroInitialization(const Expr *E) { return true; }
16514
16515 bool VisitCastExpr(const CastExpr *E) {
16516 switch (E->getCastKind()) {
16517 default:
16518 return ExprEvaluatorBaseTy::VisitCastExpr(E);
16519 case CK_ToVoid:
16520 VisitIgnoredValue(E: E->getSubExpr());
16521 return true;
16522 }
16523 }
16524
16525 bool VisitCallExpr(const CallExpr *E) {
16526 if (!IsConstantEvaluatedBuiltinCall(E))
16527 return ExprEvaluatorBaseTy::VisitCallExpr(E);
16528
16529 switch (E->getBuiltinCallee()) {
16530 case Builtin::BI__assume:
16531 case Builtin::BI__builtin_assume:
16532 // The argument is not evaluated!
16533 return true;
16534
16535 case Builtin::BI__builtin_operator_delete:
16536 return HandleOperatorDeleteCall(Info, E);
16537
16538 default:
16539 return false;
16540 }
16541 }
16542
16543 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
16544};
16545} // end anonymous namespace
16546
16547bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
16548 // We cannot speculatively evaluate a delete expression.
16549 if (Info.SpeculativeEvaluationDepth)
16550 return false;
16551
16552 FunctionDecl *OperatorDelete = E->getOperatorDelete();
16553 if (!OperatorDelete
16554 ->isUsableAsGlobalAllocationFunctionInConstantEvaluation()) {
16555 Info.FFDiag(E, DiagId: diag::note_constexpr_new_non_replaceable)
16556 << isa<CXXMethodDecl>(Val: OperatorDelete) << OperatorDelete;
16557 return false;
16558 }
16559
16560 const Expr *Arg = E->getArgument();
16561
16562 LValue Pointer;
16563 if (!EvaluatePointer(E: Arg, Result&: Pointer, Info))
16564 return false;
16565 if (Pointer.Designator.Invalid)
16566 return false;
16567
16568 // Deleting a null pointer has no effect.
16569 if (Pointer.isNullPointer()) {
16570 // This is the only case where we need to produce an extension warning:
16571 // the only other way we can succeed is if we find a dynamic allocation,
16572 // and we will have warned when we allocated it in that case.
16573 if (!Info.getLangOpts().CPlusPlus20)
16574 Info.CCEDiag(E, DiagId: diag::note_constexpr_new);
16575 return true;
16576 }
16577
16578 std::optional<DynAlloc *> Alloc = CheckDeleteKind(
16579 Info, E, Pointer, DeallocKind: E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
16580 if (!Alloc)
16581 return false;
16582 QualType AllocType = Pointer.Base.getDynamicAllocType();
16583
16584 // For the non-array case, the designator must be empty if the static type
16585 // does not have a virtual destructor.
16586 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
16587 !hasVirtualDestructor(T: Arg->getType()->getPointeeType())) {
16588 Info.FFDiag(E, DiagId: diag::note_constexpr_delete_base_nonvirt_dtor)
16589 << Arg->getType()->getPointeeType() << AllocType;
16590 return false;
16591 }
16592
16593 // For a class type with a virtual destructor, the selected operator delete
16594 // is the one looked up when building the destructor.
16595 if (!E->isArrayForm() && !E->isGlobalDelete()) {
16596 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(T: AllocType);
16597 if (VirtualDelete &&
16598 !VirtualDelete
16599 ->isUsableAsGlobalAllocationFunctionInConstantEvaluation()) {
16600 Info.FFDiag(E, DiagId: diag::note_constexpr_new_non_replaceable)
16601 << isa<CXXMethodDecl>(Val: VirtualDelete) << VirtualDelete;
16602 return false;
16603 }
16604 }
16605
16606 if (!HandleDestruction(Info, Loc: E->getExprLoc(), LVBase: Pointer.getLValueBase(),
16607 Value&: (*Alloc)->Value, T: AllocType))
16608 return false;
16609
16610 if (!Info.HeapAllocs.erase(x: Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
16611 // The element was already erased. This means the destructor call also
16612 // deleted the object.
16613 // FIXME: This probably results in undefined behavior before we get this
16614 // far, and should be diagnosed elsewhere first.
16615 Info.FFDiag(E, DiagId: diag::note_constexpr_double_delete);
16616 return false;
16617 }
16618
16619 return true;
16620}
16621
16622static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
16623 assert(!E->isValueDependent());
16624 assert(E->isPRValue() && E->getType()->isVoidType());
16625 return VoidExprEvaluator(Info).Visit(S: E);
16626}
16627
16628//===----------------------------------------------------------------------===//
16629// Top level Expr::EvaluateAsRValue method.
16630//===----------------------------------------------------------------------===//
16631
16632static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
16633 assert(!E->isValueDependent());
16634 // In C, function designators are not lvalues, but we evaluate them as if they
16635 // are.
16636 QualType T = E->getType();
16637 if (E->isGLValue() || T->isFunctionType()) {
16638 LValue LV;
16639 if (!EvaluateLValue(E, Result&: LV, Info))
16640 return false;
16641 LV.moveInto(V&: Result);
16642 } else if (T->isVectorType()) {
16643 if (!EvaluateVector(E, Result, Info))
16644 return false;
16645 } else if (T->isIntegralOrEnumerationType()) {
16646 if (!IntExprEvaluator(Info, Result).Visit(S: E))
16647 return false;
16648 } else if (T->hasPointerRepresentation()) {
16649 LValue LV;
16650 if (!EvaluatePointer(E, Result&: LV, Info))
16651 return false;
16652 LV.moveInto(V&: Result);
16653 } else if (T->isRealFloatingType()) {
16654 llvm::APFloat F(0.0);
16655 if (!EvaluateFloat(E, Result&: F, Info))
16656 return false;
16657 Result = APValue(F);
16658 } else if (T->isAnyComplexType()) {
16659 ComplexValue C;
16660 if (!EvaluateComplex(E, Result&: C, Info))
16661 return false;
16662 C.moveInto(v&: Result);
16663 } else if (T->isFixedPointType()) {
16664 if (!FixedPointExprEvaluator(Info, Result).Visit(S: E)) return false;
16665 } else if (T->isMemberPointerType()) {
16666 MemberPtr P;
16667 if (!EvaluateMemberPointer(E, Result&: P, Info))
16668 return false;
16669 P.moveInto(V&: Result);
16670 return true;
16671 } else if (T->isArrayType()) {
16672 LValue LV;
16673 APValue &Value =
16674 Info.CurrentCall->createTemporary(Key: E, T, Scope: ScopeKind::FullExpression, LV);
16675 if (!EvaluateArray(E, This: LV, Result&: Value, Info))
16676 return false;
16677 Result = Value;
16678 } else if (T->isRecordType()) {
16679 LValue LV;
16680 APValue &Value =
16681 Info.CurrentCall->createTemporary(Key: E, T, Scope: ScopeKind::FullExpression, LV);
16682 if (!EvaluateRecord(E, This: LV, Result&: Value, Info))
16683 return false;
16684 Result = Value;
16685 } else if (T->isVoidType()) {
16686 if (!Info.getLangOpts().CPlusPlus11)
16687 Info.CCEDiag(E, DiagId: diag::note_constexpr_nonliteral)
16688 << E->getType();
16689 if (!EvaluateVoid(E, Info))
16690 return false;
16691 } else if (T->isAtomicType()) {
16692 QualType Unqual = T.getAtomicUnqualifiedType();
16693 if (Unqual->isArrayType() || Unqual->isRecordType()) {
16694 LValue LV;
16695 APValue &Value = Info.CurrentCall->createTemporary(
16696 Key: E, T: Unqual, Scope: ScopeKind::FullExpression, LV);
16697 if (!EvaluateAtomic(E, This: &LV, Result&: Value, Info))
16698 return false;
16699 Result = Value;
16700 } else {
16701 if (!EvaluateAtomic(E, This: nullptr, Result, Info))
16702 return false;
16703 }
16704 } else if (Info.getLangOpts().CPlusPlus11) {
16705 Info.FFDiag(E, DiagId: diag::note_constexpr_nonliteral) << E->getType();
16706 return false;
16707 } else {
16708 Info.FFDiag(E, DiagId: diag::note_invalid_subexpr_in_const_expr);
16709 return false;
16710 }
16711
16712 return true;
16713}
16714
16715/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
16716/// cases, the in-place evaluation is essential, since later initializers for
16717/// an object can indirectly refer to subobjects which were initialized earlier.
16718static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
16719 const Expr *E, bool AllowNonLiteralTypes) {
16720 assert(!E->isValueDependent());
16721
16722 // Normally expressions passed to EvaluateInPlace have a type, but not when
16723 // a VarDecl initializer is evaluated before the untyped ParenListExpr is
16724 // replaced with a CXXConstructExpr. This can happen in LLDB.
16725 if (E->getType().isNull())
16726 return false;
16727
16728 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, This: &This))
16729 return false;
16730
16731 if (E->isPRValue()) {
16732 // Evaluate arrays and record types in-place, so that later initializers can
16733 // refer to earlier-initialized members of the object.
16734 QualType T = E->getType();
16735 if (T->isArrayType())
16736 return EvaluateArray(E, This, Result, Info);
16737 else if (T->isRecordType())
16738 return EvaluateRecord(E, This, Result, Info);
16739 else if (T->isAtomicType()) {
16740 QualType Unqual = T.getAtomicUnqualifiedType();
16741 if (Unqual->isArrayType() || Unqual->isRecordType())
16742 return EvaluateAtomic(E, This: &This, Result, Info);
16743 }
16744 }
16745
16746 // For any other type, in-place evaluation is unimportant.
16747 return Evaluate(Result, Info, E);
16748}
16749
16750/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
16751/// lvalue-to-rvalue cast if it is an lvalue.
16752static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
16753 assert(!E->isValueDependent());
16754
16755 if (E->getType().isNull())
16756 return false;
16757
16758 if (!CheckLiteralType(Info, E))
16759 return false;
16760
16761 if (Info.EnableNewConstInterp) {
16762 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Parent&: Info, E, Result))
16763 return false;
16764 return CheckConstantExpression(Info, DiagLoc: E->getExprLoc(), Type: E->getType(), Value: Result,
16765 Kind: ConstantExprKind::Normal);
16766 }
16767
16768 if (!::Evaluate(Result, Info, E))
16769 return false;
16770
16771 // Implicit lvalue-to-rvalue cast.
16772 if (E->isGLValue()) {
16773 LValue LV;
16774 LV.setFrom(Ctx&: Info.Ctx, V: Result);
16775 if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getType(), LVal: LV, RVal&: Result))
16776 return false;
16777 }
16778
16779 // Check this core constant expression is a constant expression.
16780 return CheckConstantExpression(Info, DiagLoc: E->getExprLoc(), Type: E->getType(), Value: Result,
16781 Kind: ConstantExprKind::Normal) &&
16782 CheckMemoryLeaks(Info);
16783}
16784
16785static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
16786 const ASTContext &Ctx, bool &IsConst) {
16787 // Fast-path evaluations of integer literals, since we sometimes see files
16788 // containing vast quantities of these.
16789 if (const auto *L = dyn_cast<IntegerLiteral>(Val: Exp)) {
16790 Result.Val = APValue(APSInt(L->getValue(),
16791 L->getType()->isUnsignedIntegerType()));
16792 IsConst = true;
16793 return true;
16794 }
16795
16796 if (const auto *L = dyn_cast<CXXBoolLiteralExpr>(Val: Exp)) {
16797 Result.Val = APValue(APSInt(APInt(1, L->getValue())));
16798 IsConst = true;
16799 return true;
16800 }
16801
16802 if (const auto *FL = dyn_cast<FloatingLiteral>(Val: Exp)) {
16803 Result.Val = APValue(FL->getValue());
16804 IsConst = true;
16805 return true;
16806 }
16807
16808 if (const auto *L = dyn_cast<CharacterLiteral>(Val: Exp)) {
16809 Result.Val = APValue(Ctx.MakeIntValue(Value: L->getValue(), Type: L->getType()));
16810 IsConst = true;
16811 return true;
16812 }
16813
16814 if (const auto *CE = dyn_cast<ConstantExpr>(Val: Exp)) {
16815 if (CE->hasAPValueResult()) {
16816 APValue APV = CE->getAPValueResult();
16817 if (!APV.isLValue()) {
16818 Result.Val = std::move(APV);
16819 IsConst = true;
16820 return true;
16821 }
16822 }
16823
16824 // The SubExpr is usually just an IntegerLiteral.
16825 return FastEvaluateAsRValue(Exp: CE->getSubExpr(), Result, Ctx, IsConst);
16826 }
16827
16828 // This case should be rare, but we need to check it before we check on
16829 // the type below.
16830 if (Exp->getType().isNull()) {
16831 IsConst = false;
16832 return true;
16833 }
16834
16835 return false;
16836}
16837
16838static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
16839 Expr::SideEffectsKind SEK) {
16840 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
16841 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
16842}
16843
16844static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
16845 const ASTContext &Ctx, EvalInfo &Info) {
16846 assert(!E->isValueDependent());
16847 bool IsConst;
16848 if (FastEvaluateAsRValue(Exp: E, Result, Ctx, IsConst))
16849 return IsConst;
16850
16851 return EvaluateAsRValue(Info, E, Result&: Result.Val);
16852}
16853
16854static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
16855 const ASTContext &Ctx,
16856 Expr::SideEffectsKind AllowSideEffects,
16857 EvalInfo &Info) {
16858 assert(!E->isValueDependent());
16859 if (!E->getType()->isIntegralOrEnumerationType())
16860 return false;
16861
16862 if (!::EvaluateAsRValue(E, Result&: ExprResult, Ctx, Info) ||
16863 !ExprResult.Val.isInt() ||
16864 hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
16865 return false;
16866
16867 return true;
16868}
16869
16870static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
16871 const ASTContext &Ctx,
16872 Expr::SideEffectsKind AllowSideEffects,
16873 EvalInfo &Info) {
16874 assert(!E->isValueDependent());
16875 if (!E->getType()->isFixedPointType())
16876 return false;
16877
16878 if (!::EvaluateAsRValue(E, Result&: ExprResult, Ctx, Info))
16879 return false;
16880
16881 if (!ExprResult.Val.isFixedPoint() ||
16882 hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
16883 return false;
16884
16885 return true;
16886}
16887
16888/// EvaluateAsRValue - Return true if this is a constant which we can fold using
16889/// any crazy technique (that has nothing to do with language standards) that
16890/// we want to. If this function returns true, it returns the folded constant
16891/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
16892/// will be applied to the result.
16893bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
16894 bool InConstantContext) const {
16895 assert(!isValueDependent() &&
16896 "Expression evaluator can't be called on a dependent expression.");
16897 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsRValue");
16898 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
16899 Info.InConstantContext = InConstantContext;
16900 return ::EvaluateAsRValue(E: this, Result, Ctx, Info);
16901}
16902
16903bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
16904 bool InConstantContext) const {
16905 assert(!isValueDependent() &&
16906 "Expression evaluator can't be called on a dependent expression.");
16907 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsBooleanCondition");
16908 EvalResult Scratch;
16909 return EvaluateAsRValue(Result&: Scratch, Ctx, InConstantContext) &&
16910 HandleConversionToBool(Val: Scratch.Val, Result);
16911}
16912
16913bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
16914 SideEffectsKind AllowSideEffects,
16915 bool InConstantContext) const {
16916 assert(!isValueDependent() &&
16917 "Expression evaluator can't be called on a dependent expression.");
16918 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsInt");
16919 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
16920 Info.InConstantContext = InConstantContext;
16921 return ::EvaluateAsInt(E: this, ExprResult&: Result, Ctx, AllowSideEffects, Info);
16922}
16923
16924bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
16925 SideEffectsKind AllowSideEffects,
16926 bool InConstantContext) const {
16927 assert(!isValueDependent() &&
16928 "Expression evaluator can't be called on a dependent expression.");
16929 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFixedPoint");
16930 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
16931 Info.InConstantContext = InConstantContext;
16932 return ::EvaluateAsFixedPoint(E: this, ExprResult&: Result, Ctx, AllowSideEffects, Info);
16933}
16934
16935bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
16936 SideEffectsKind AllowSideEffects,
16937 bool InConstantContext) const {
16938 assert(!isValueDependent() &&
16939 "Expression evaluator can't be called on a dependent expression.");
16940
16941 if (!getType()->isRealFloatingType())
16942 return false;
16943
16944 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFloat");
16945 EvalResult ExprResult;
16946 if (!EvaluateAsRValue(Result&: ExprResult, Ctx, InConstantContext) ||
16947 !ExprResult.Val.isFloat() ||
16948 hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
16949 return false;
16950
16951 Result = ExprResult.Val.getFloat();
16952 return true;
16953}
16954
16955bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
16956 bool InConstantContext) const {
16957 assert(!isValueDependent() &&
16958 "Expression evaluator can't be called on a dependent expression.");
16959
16960 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsLValue");
16961 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
16962 Info.InConstantContext = InConstantContext;
16963 LValue LV;
16964 CheckedTemporaries CheckedTemps;
16965 if (!EvaluateLValue(E: this, Result&: LV, Info) || !Info.discardCleanups() ||
16966 Result.HasSideEffects ||
16967 !CheckLValueConstantExpression(Info, Loc: getExprLoc(),
16968 Type: Ctx.getLValueReferenceType(T: getType()), LVal: LV,
16969 Kind: ConstantExprKind::Normal, CheckedTemps))
16970 return false;
16971
16972 LV.moveInto(V&: Result.Val);
16973 return true;
16974}
16975
16976static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base,
16977 APValue DestroyedValue, QualType Type,
16978 SourceLocation Loc, Expr::EvalStatus &EStatus,
16979 bool IsConstantDestruction) {
16980 EvalInfo Info(Ctx, EStatus,
16981 IsConstantDestruction ? EvalInfo::EM_ConstantExpression
16982 : EvalInfo::EM_ConstantFold);
16983 Info.setEvaluatingDecl(Base, Value&: DestroyedValue,
16984 EDK: EvalInfo::EvaluatingDeclKind::Dtor);
16985 Info.InConstantContext = IsConstantDestruction;
16986
16987 LValue LVal;
16988 LVal.set(B: Base);
16989
16990 if (!HandleDestruction(Info, Loc, LVBase: Base, Value&: DestroyedValue, T: Type) ||
16991 EStatus.HasSideEffects)
16992 return false;
16993
16994 if (!Info.discardCleanups())
16995 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
16996
16997 return true;
16998}
16999
17000bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
17001 ConstantExprKind Kind) const {
17002 assert(!isValueDependent() &&
17003 "Expression evaluator can't be called on a dependent expression.");
17004 bool IsConst;
17005 if (FastEvaluateAsRValue(Exp: this, Result, Ctx, IsConst) && Result.Val.hasValue())
17006 return true;
17007
17008 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsConstantExpr");
17009 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
17010 EvalInfo Info(Ctx, Result, EM);
17011 Info.InConstantContext = true;
17012
17013 if (Info.EnableNewConstInterp) {
17014 if (!Info.Ctx.getInterpContext().evaluate(Parent&: Info, E: this, Result&: Result.Val, Kind))
17015 return false;
17016 return CheckConstantExpression(Info, DiagLoc: getExprLoc(),
17017 Type: getStorageType(Ctx, E: this), Value: Result.Val, Kind);
17018 }
17019
17020 // The type of the object we're initializing is 'const T' for a class NTTP.
17021 QualType T = getType();
17022 if (Kind == ConstantExprKind::ClassTemplateArgument)
17023 T.addConst();
17024
17025 // If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to
17026 // represent the result of the evaluation. CheckConstantExpression ensures
17027 // this doesn't escape.
17028 MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true);
17029 APValue::LValueBase Base(&BaseMTE);
17030 Info.setEvaluatingDecl(Base, Value&: Result.Val);
17031
17032 LValue LVal;
17033 LVal.set(B: Base);
17034 // C++23 [intro.execution]/p5
17035 // A full-expression is [...] a constant-expression
17036 // So we need to make sure temporary objects are destroyed after having
17037 // evaluating the expression (per C++23 [class.temporary]/p4).
17038 FullExpressionRAII Scope(Info);
17039 if (!::EvaluateInPlace(Result&: Result.Val, Info, This: LVal, E: this) ||
17040 Result.HasSideEffects || !Scope.destroy())
17041 return false;
17042
17043 if (!Info.discardCleanups())
17044 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
17045
17046 if (!CheckConstantExpression(Info, DiagLoc: getExprLoc(), Type: getStorageType(Ctx, E: this),
17047 Value: Result.Val, Kind))
17048 return false;
17049 if (!CheckMemoryLeaks(Info))
17050 return false;
17051
17052 // If this is a class template argument, it's required to have constant
17053 // destruction too.
17054 if (Kind == ConstantExprKind::ClassTemplateArgument &&
17055 (!EvaluateDestruction(Ctx, Base, DestroyedValue: Result.Val, Type: T, Loc: getBeginLoc(), EStatus&: Result,
17056 IsConstantDestruction: true) ||
17057 Result.HasSideEffects)) {
17058 // FIXME: Prefix a note to indicate that the problem is lack of constant
17059 // destruction.
17060 return false;
17061 }
17062
17063 return true;
17064}
17065
17066bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
17067 const VarDecl *VD,
17068 SmallVectorImpl<PartialDiagnosticAt> &Notes,
17069 bool IsConstantInitialization) const {
17070 assert(!isValueDependent() &&
17071 "Expression evaluator can't be called on a dependent expression.");
17072
17073 llvm::TimeTraceScope TimeScope("EvaluateAsInitializer", [&] {
17074 std::string Name;
17075 llvm::raw_string_ostream OS(Name);
17076 VD->printQualifiedName(OS);
17077 return Name;
17078 });
17079
17080 Expr::EvalStatus EStatus;
17081 EStatus.Diag = &Notes;
17082
17083 EvalInfo Info(Ctx, EStatus,
17084 (IsConstantInitialization &&
17085 (Ctx.getLangOpts().CPlusPlus || Ctx.getLangOpts().C23))
17086 ? EvalInfo::EM_ConstantExpression
17087 : EvalInfo::EM_ConstantFold);
17088 Info.setEvaluatingDecl(Base: VD, Value);
17089 Info.InConstantContext = IsConstantInitialization;
17090
17091 SourceLocation DeclLoc = VD->getLocation();
17092 QualType DeclTy = VD->getType();
17093
17094 if (Info.EnableNewConstInterp) {
17095 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
17096 if (!InterpCtx.evaluateAsInitializer(Parent&: Info, VD, Result&: Value))
17097 return false;
17098
17099 return CheckConstantExpression(Info, DiagLoc: DeclLoc, Type: DeclTy, Value,
17100 Kind: ConstantExprKind::Normal);
17101 } else {
17102 LValue LVal;
17103 LVal.set(B: VD);
17104
17105 {
17106 // C++23 [intro.execution]/p5
17107 // A full-expression is ... an init-declarator ([dcl.decl]) or a
17108 // mem-initializer.
17109 // So we need to make sure temporary objects are destroyed after having
17110 // evaluated the expression (per C++23 [class.temporary]/p4).
17111 //
17112 // FIXME: Otherwise this may break test/Modules/pr68702.cpp because the
17113 // serialization code calls ParmVarDecl::getDefaultArg() which strips the
17114 // outermost FullExpr, such as ExprWithCleanups.
17115 FullExpressionRAII Scope(Info);
17116 if (!EvaluateInPlace(Result&: Value, Info, This: LVal, E: this,
17117 /*AllowNonLiteralTypes=*/true) ||
17118 EStatus.HasSideEffects)
17119 return false;
17120 }
17121
17122 // At this point, any lifetime-extended temporaries are completely
17123 // initialized.
17124 Info.performLifetimeExtension();
17125
17126 if (!Info.discardCleanups())
17127 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
17128 }
17129
17130 return CheckConstantExpression(Info, DiagLoc: DeclLoc, Type: DeclTy, Value,
17131 Kind: ConstantExprKind::Normal) &&
17132 CheckMemoryLeaks(Info);
17133}
17134
17135bool VarDecl::evaluateDestruction(
17136 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
17137 Expr::EvalStatus EStatus;
17138 EStatus.Diag = &Notes;
17139
17140 // Only treat the destruction as constant destruction if we formally have
17141 // constant initialization (or are usable in a constant expression).
17142 bool IsConstantDestruction = hasConstantInitialization();
17143
17144 // Make a copy of the value for the destructor to mutate, if we know it.
17145 // Otherwise, treat the value as default-initialized; if the destructor works
17146 // anyway, then the destruction is constant (and must be essentially empty).
17147 APValue DestroyedValue;
17148 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
17149 DestroyedValue = *getEvaluatedValue();
17150 else if (!handleDefaultInitValue(T: getType(), Result&: DestroyedValue))
17151 return false;
17152
17153 if (!EvaluateDestruction(Ctx: getASTContext(), Base: this, DestroyedValue: std::move(DestroyedValue),
17154 Type: getType(), Loc: getLocation(), EStatus,
17155 IsConstantDestruction) ||
17156 EStatus.HasSideEffects)
17157 return false;
17158
17159 ensureEvaluatedStmt()->HasConstantDestruction = true;
17160 return true;
17161}
17162
17163/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
17164/// constant folded, but discard the result.
17165bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
17166 assert(!isValueDependent() &&
17167 "Expression evaluator can't be called on a dependent expression.");
17168
17169 EvalResult Result;
17170 return EvaluateAsRValue(Result, Ctx, /* in constant context */ InConstantContext: true) &&
17171 !hasUnacceptableSideEffect(Result, SEK);
17172}
17173
17174APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
17175 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
17176 assert(!isValueDependent() &&
17177 "Expression evaluator can't be called on a dependent expression.");
17178
17179 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstInt");
17180 EvalResult EVResult;
17181 EVResult.Diag = Diag;
17182 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
17183 Info.InConstantContext = true;
17184
17185 bool Result = ::EvaluateAsRValue(E: this, Result&: EVResult, Ctx, Info);
17186 (void)Result;
17187 assert(Result && "Could not evaluate expression");
17188 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
17189
17190 return EVResult.Val.getInt();
17191}
17192
17193APSInt Expr::EvaluateKnownConstIntCheckOverflow(
17194 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
17195 assert(!isValueDependent() &&
17196 "Expression evaluator can't be called on a dependent expression.");
17197
17198 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstIntCheckOverflow");
17199 EvalResult EVResult;
17200 EVResult.Diag = Diag;
17201 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
17202 Info.InConstantContext = true;
17203 Info.CheckingForUndefinedBehavior = true;
17204
17205 bool Result = ::EvaluateAsRValue(Info, E: this, Result&: EVResult.Val);
17206 (void)Result;
17207 assert(Result && "Could not evaluate expression");
17208 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
17209
17210 return EVResult.Val.getInt();
17211}
17212
17213void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
17214 assert(!isValueDependent() &&
17215 "Expression evaluator can't be called on a dependent expression.");
17216
17217 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateForOverflow");
17218 bool IsConst;
17219 EvalResult EVResult;
17220 if (!FastEvaluateAsRValue(Exp: this, Result&: EVResult, Ctx, IsConst)) {
17221 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
17222 Info.CheckingForUndefinedBehavior = true;
17223 (void)::EvaluateAsRValue(Info, E: this, Result&: EVResult.Val);
17224 }
17225}
17226
17227bool Expr::EvalResult::isGlobalLValue() const {
17228 assert(Val.isLValue());
17229 return IsGlobalLValue(B: Val.getLValueBase());
17230}
17231
17232/// isIntegerConstantExpr - this recursive routine will test if an expression is
17233/// an integer constant expression.
17234
17235/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
17236/// comma, etc
17237
17238// CheckICE - This function does the fundamental ICE checking: the returned
17239// ICEDiag contains an ICEKind indicating whether the expression is an ICE,
17240// and a (possibly null) SourceLocation indicating the location of the problem.
17241//
17242// Note that to reduce code duplication, this helper does no evaluation
17243// itself; the caller checks whether the expression is evaluatable, and
17244// in the rare cases where CheckICE actually cares about the evaluated
17245// value, it calls into Evaluate.
17246
17247namespace {
17248
17249enum ICEKind {
17250 /// This expression is an ICE.
17251 IK_ICE,
17252 /// This expression is not an ICE, but if it isn't evaluated, it's
17253 /// a legal subexpression for an ICE. This return value is used to handle
17254 /// the comma operator in C99 mode, and non-constant subexpressions.
17255 IK_ICEIfUnevaluated,
17256 /// This expression is not an ICE, and is not a legal subexpression for one.
17257 IK_NotICE
17258};
17259
17260struct ICEDiag {
17261 ICEKind Kind;
17262 SourceLocation Loc;
17263
17264 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
17265};
17266
17267}
17268
17269static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
17270
17271static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
17272
17273static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
17274 Expr::EvalResult EVResult;
17275 Expr::EvalStatus Status;
17276 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
17277
17278 Info.InConstantContext = true;
17279 if (!::EvaluateAsRValue(E, Result&: EVResult, Ctx, Info) || EVResult.HasSideEffects ||
17280 !EVResult.Val.isInt())
17281 return ICEDiag(IK_NotICE, E->getBeginLoc());
17282
17283 return NoDiag();
17284}
17285
17286static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
17287 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
17288 if (!E->getType()->isIntegralOrEnumerationType())
17289 return ICEDiag(IK_NotICE, E->getBeginLoc());
17290
17291 switch (E->getStmtClass()) {
17292#define ABSTRACT_STMT(Node)
17293#define STMT(Node, Base) case Expr::Node##Class:
17294#define EXPR(Node, Base)
17295#include "clang/AST/StmtNodes.inc"
17296 case Expr::PredefinedExprClass:
17297 case Expr::FloatingLiteralClass:
17298 case Expr::ImaginaryLiteralClass:
17299 case Expr::StringLiteralClass:
17300 case Expr::ArraySubscriptExprClass:
17301 case Expr::MatrixSubscriptExprClass:
17302 case Expr::ArraySectionExprClass:
17303 case Expr::OMPArrayShapingExprClass:
17304 case Expr::OMPIteratorExprClass:
17305 case Expr::MemberExprClass:
17306 case Expr::CompoundAssignOperatorClass:
17307 case Expr::CompoundLiteralExprClass:
17308 case Expr::ExtVectorElementExprClass:
17309 case Expr::DesignatedInitExprClass:
17310 case Expr::ArrayInitLoopExprClass:
17311 case Expr::ArrayInitIndexExprClass:
17312 case Expr::NoInitExprClass:
17313 case Expr::DesignatedInitUpdateExprClass:
17314 case Expr::ImplicitValueInitExprClass:
17315 case Expr::ParenListExprClass:
17316 case Expr::VAArgExprClass:
17317 case Expr::AddrLabelExprClass:
17318 case Expr::StmtExprClass:
17319 case Expr::CXXMemberCallExprClass:
17320 case Expr::CUDAKernelCallExprClass:
17321 case Expr::CXXAddrspaceCastExprClass:
17322 case Expr::CXXDynamicCastExprClass:
17323 case Expr::CXXTypeidExprClass:
17324 case Expr::CXXUuidofExprClass:
17325 case Expr::MSPropertyRefExprClass:
17326 case Expr::MSPropertySubscriptExprClass:
17327 case Expr::CXXNullPtrLiteralExprClass:
17328 case Expr::UserDefinedLiteralClass:
17329 case Expr::CXXThisExprClass:
17330 case Expr::CXXThrowExprClass:
17331 case Expr::CXXNewExprClass:
17332 case Expr::CXXDeleteExprClass:
17333 case Expr::CXXPseudoDestructorExprClass:
17334 case Expr::UnresolvedLookupExprClass:
17335 case Expr::RecoveryExprClass:
17336 case Expr::DependentScopeDeclRefExprClass:
17337 case Expr::CXXConstructExprClass:
17338 case Expr::CXXInheritedCtorInitExprClass:
17339 case Expr::CXXStdInitializerListExprClass:
17340 case Expr::CXXBindTemporaryExprClass:
17341 case Expr::ExprWithCleanupsClass:
17342 case Expr::CXXTemporaryObjectExprClass:
17343 case Expr::CXXUnresolvedConstructExprClass:
17344 case Expr::CXXDependentScopeMemberExprClass:
17345 case Expr::UnresolvedMemberExprClass:
17346 case Expr::ObjCStringLiteralClass:
17347 case Expr::ObjCBoxedExprClass:
17348 case Expr::ObjCArrayLiteralClass:
17349 case Expr::ObjCDictionaryLiteralClass:
17350 case Expr::ObjCEncodeExprClass:
17351 case Expr::ObjCMessageExprClass:
17352 case Expr::ObjCSelectorExprClass:
17353 case Expr::ObjCProtocolExprClass:
17354 case Expr::ObjCIvarRefExprClass:
17355 case Expr::ObjCPropertyRefExprClass:
17356 case Expr::ObjCSubscriptRefExprClass:
17357 case Expr::ObjCIsaExprClass:
17358 case Expr::ObjCAvailabilityCheckExprClass:
17359 case Expr::ShuffleVectorExprClass:
17360 case Expr::ConvertVectorExprClass:
17361 case Expr::BlockExprClass:
17362 case Expr::NoStmtClass:
17363 case Expr::OpaqueValueExprClass:
17364 case Expr::PackExpansionExprClass:
17365 case Expr::SubstNonTypeTemplateParmPackExprClass:
17366 case Expr::FunctionParmPackExprClass:
17367 case Expr::AsTypeExprClass:
17368 case Expr::ObjCIndirectCopyRestoreExprClass:
17369 case Expr::MaterializeTemporaryExprClass:
17370 case Expr::PseudoObjectExprClass:
17371 case Expr::AtomicExprClass:
17372 case Expr::LambdaExprClass:
17373 case Expr::CXXFoldExprClass:
17374 case Expr::CoawaitExprClass:
17375 case Expr::DependentCoawaitExprClass:
17376 case Expr::CoyieldExprClass:
17377 case Expr::SYCLUniqueStableNameExprClass:
17378 case Expr::CXXParenListInitExprClass:
17379 case Expr::HLSLOutArgExprClass:
17380 return ICEDiag(IK_NotICE, E->getBeginLoc());
17381
17382 case Expr::InitListExprClass: {
17383 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
17384 // form "T x = { a };" is equivalent to "T x = a;".
17385 // Unless we're initializing a reference, T is a scalar as it is known to be
17386 // of integral or enumeration type.
17387 if (E->isPRValue())
17388 if (cast<InitListExpr>(Val: E)->getNumInits() == 1)
17389 return CheckICE(E: cast<InitListExpr>(Val: E)->getInit(Init: 0), Ctx);
17390 return ICEDiag(IK_NotICE, E->getBeginLoc());
17391 }
17392
17393 case Expr::SizeOfPackExprClass:
17394 case Expr::GNUNullExprClass:
17395 case Expr::SourceLocExprClass:
17396 case Expr::EmbedExprClass:
17397 case Expr::OpenACCAsteriskSizeExprClass:
17398 return NoDiag();
17399
17400 case Expr::PackIndexingExprClass:
17401 return CheckICE(E: cast<PackIndexingExpr>(Val: E)->getSelectedExpr(), Ctx);
17402
17403 case Expr::SubstNonTypeTemplateParmExprClass:
17404 return
17405 CheckICE(E: cast<SubstNonTypeTemplateParmExpr>(Val: E)->getReplacement(), Ctx);
17406
17407 case Expr::ConstantExprClass:
17408 return CheckICE(E: cast<ConstantExpr>(Val: E)->getSubExpr(), Ctx);
17409
17410 case Expr::ParenExprClass:
17411 return CheckICE(E: cast<ParenExpr>(Val: E)->getSubExpr(), Ctx);
17412 case Expr::GenericSelectionExprClass:
17413 return CheckICE(E: cast<GenericSelectionExpr>(Val: E)->getResultExpr(), Ctx);
17414 case Expr::IntegerLiteralClass:
17415 case Expr::FixedPointLiteralClass:
17416 case Expr::CharacterLiteralClass:
17417 case Expr::ObjCBoolLiteralExprClass:
17418 case Expr::CXXBoolLiteralExprClass:
17419 case Expr::CXXScalarValueInitExprClass:
17420 case Expr::TypeTraitExprClass:
17421 case Expr::ConceptSpecializationExprClass:
17422 case Expr::RequiresExprClass:
17423 case Expr::ArrayTypeTraitExprClass:
17424 case Expr::ExpressionTraitExprClass:
17425 case Expr::CXXNoexceptExprClass:
17426 return NoDiag();
17427 case Expr::CallExprClass:
17428 case Expr::CXXOperatorCallExprClass: {
17429 // C99 6.6/3 allows function calls within unevaluated subexpressions of
17430 // constant expressions, but they can never be ICEs because an ICE cannot
17431 // contain an operand of (pointer to) function type.
17432 const CallExpr *CE = cast<CallExpr>(Val: E);
17433 if (CE->getBuiltinCallee())
17434 return CheckEvalInICE(E, Ctx);
17435 return ICEDiag(IK_NotICE, E->getBeginLoc());
17436 }
17437 case Expr::CXXRewrittenBinaryOperatorClass:
17438 return CheckICE(E: cast<CXXRewrittenBinaryOperator>(Val: E)->getSemanticForm(),
17439 Ctx);
17440 case Expr::DeclRefExprClass: {
17441 const NamedDecl *D = cast<DeclRefExpr>(Val: E)->getDecl();
17442 if (isa<EnumConstantDecl>(Val: D))
17443 return NoDiag();
17444
17445 // C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified
17446 // integer variables in constant expressions:
17447 //
17448 // C++ 7.1.5.1p2
17449 // A variable of non-volatile const-qualified integral or enumeration
17450 // type initialized by an ICE can be used in ICEs.
17451 //
17452 // We sometimes use CheckICE to check the C++98 rules in C++11 mode. In
17453 // that mode, use of reference variables should not be allowed.
17454 const VarDecl *VD = dyn_cast<VarDecl>(Val: D);
17455 if (VD && VD->isUsableInConstantExpressions(C: Ctx) &&
17456 !VD->getType()->isReferenceType())
17457 return NoDiag();
17458
17459 return ICEDiag(IK_NotICE, E->getBeginLoc());
17460 }
17461 case Expr::UnaryOperatorClass: {
17462 const UnaryOperator *Exp = cast<UnaryOperator>(Val: E);
17463 switch (Exp->getOpcode()) {
17464 case UO_PostInc:
17465 case UO_PostDec:
17466 case UO_PreInc:
17467 case UO_PreDec:
17468 case UO_AddrOf:
17469 case UO_Deref:
17470 case UO_Coawait:
17471 // C99 6.6/3 allows increment and decrement within unevaluated
17472 // subexpressions of constant expressions, but they can never be ICEs
17473 // because an ICE cannot contain an lvalue operand.
17474 return ICEDiag(IK_NotICE, E->getBeginLoc());
17475 case UO_Extension:
17476 case UO_LNot:
17477 case UO_Plus:
17478 case UO_Minus:
17479 case UO_Not:
17480 case UO_Real:
17481 case UO_Imag:
17482 return CheckICE(E: Exp->getSubExpr(), Ctx);
17483 }
17484 llvm_unreachable("invalid unary operator class");
17485 }
17486 case Expr::OffsetOfExprClass: {
17487 // Note that per C99, offsetof must be an ICE. And AFAIK, using
17488 // EvaluateAsRValue matches the proposed gcc behavior for cases like
17489 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
17490 // compliance: we should warn earlier for offsetof expressions with
17491 // array subscripts that aren't ICEs, and if the array subscripts
17492 // are ICEs, the value of the offsetof must be an integer constant.
17493 return CheckEvalInICE(E, Ctx);
17494 }
17495 case Expr::UnaryExprOrTypeTraitExprClass: {
17496 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(Val: E);
17497 if ((Exp->getKind() == UETT_SizeOf) &&
17498 Exp->getTypeOfArgument()->isVariableArrayType())
17499 return ICEDiag(IK_NotICE, E->getBeginLoc());
17500 if (Exp->getKind() == UETT_CountOf) {
17501 QualType ArgTy = Exp->getTypeOfArgument();
17502 if (ArgTy->isVariableArrayType()) {
17503 // We need to look whether the array is multidimensional. If it is,
17504 // then we want to check the size expression manually to see whether
17505 // it is an ICE or not.
17506 const auto *VAT = Ctx.getAsVariableArrayType(T: ArgTy);
17507 if (VAT->getElementType()->isArrayType())
17508 return CheckICE(E: VAT->getSizeExpr(), Ctx);
17509
17510 // Otherwise, this is a regular VLA, which is definitely not an ICE.
17511 return ICEDiag(IK_NotICE, E->getBeginLoc());
17512 }
17513 }
17514 return NoDiag();
17515 }
17516 case Expr::BinaryOperatorClass: {
17517 const BinaryOperator *Exp = cast<BinaryOperator>(Val: E);
17518 switch (Exp->getOpcode()) {
17519 case BO_PtrMemD:
17520 case BO_PtrMemI:
17521 case BO_Assign:
17522 case BO_MulAssign:
17523 case BO_DivAssign:
17524 case BO_RemAssign:
17525 case BO_AddAssign:
17526 case BO_SubAssign:
17527 case BO_ShlAssign:
17528 case BO_ShrAssign:
17529 case BO_AndAssign:
17530 case BO_XorAssign:
17531 case BO_OrAssign:
17532 // C99 6.6/3 allows assignments within unevaluated subexpressions of
17533 // constant expressions, but they can never be ICEs because an ICE cannot
17534 // contain an lvalue operand.
17535 return ICEDiag(IK_NotICE, E->getBeginLoc());
17536
17537 case BO_Mul:
17538 case BO_Div:
17539 case BO_Rem:
17540 case BO_Add:
17541 case BO_Sub:
17542 case BO_Shl:
17543 case BO_Shr:
17544 case BO_LT:
17545 case BO_GT:
17546 case BO_LE:
17547 case BO_GE:
17548 case BO_EQ:
17549 case BO_NE:
17550 case BO_And:
17551 case BO_Xor:
17552 case BO_Or:
17553 case BO_Comma:
17554 case BO_Cmp: {
17555 ICEDiag LHSResult = CheckICE(E: Exp->getLHS(), Ctx);
17556 ICEDiag RHSResult = CheckICE(E: Exp->getRHS(), Ctx);
17557 if (Exp->getOpcode() == BO_Div ||
17558 Exp->getOpcode() == BO_Rem) {
17559 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
17560 // we don't evaluate one.
17561 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
17562 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
17563 if (REval == 0)
17564 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
17565 if (REval.isSigned() && REval.isAllOnes()) {
17566 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
17567 if (LEval.isMinSignedValue())
17568 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
17569 }
17570 }
17571 }
17572 if (Exp->getOpcode() == BO_Comma) {
17573 if (Ctx.getLangOpts().C99) {
17574 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
17575 // if it isn't evaluated.
17576 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
17577 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
17578 } else {
17579 // In both C89 and C++, commas in ICEs are illegal.
17580 return ICEDiag(IK_NotICE, E->getBeginLoc());
17581 }
17582 }
17583 return Worst(A: LHSResult, B: RHSResult);
17584 }
17585 case BO_LAnd:
17586 case BO_LOr: {
17587 ICEDiag LHSResult = CheckICE(E: Exp->getLHS(), Ctx);
17588 ICEDiag RHSResult = CheckICE(E: Exp->getRHS(), Ctx);
17589 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
17590 // Rare case where the RHS has a comma "side-effect"; we need
17591 // to actually check the condition to see whether the side
17592 // with the comma is evaluated.
17593 if ((Exp->getOpcode() == BO_LAnd) !=
17594 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
17595 return RHSResult;
17596 return NoDiag();
17597 }
17598
17599 return Worst(A: LHSResult, B: RHSResult);
17600 }
17601 }
17602 llvm_unreachable("invalid binary operator kind");
17603 }
17604 case Expr::ImplicitCastExprClass:
17605 case Expr::CStyleCastExprClass:
17606 case Expr::CXXFunctionalCastExprClass:
17607 case Expr::CXXStaticCastExprClass:
17608 case Expr::CXXReinterpretCastExprClass:
17609 case Expr::CXXConstCastExprClass:
17610 case Expr::ObjCBridgedCastExprClass: {
17611 const Expr *SubExpr = cast<CastExpr>(Val: E)->getSubExpr();
17612 if (isa<ExplicitCastExpr>(Val: E)) {
17613 if (const FloatingLiteral *FL
17614 = dyn_cast<FloatingLiteral>(Val: SubExpr->IgnoreParenImpCasts())) {
17615 unsigned DestWidth = Ctx.getIntWidth(T: E->getType());
17616 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
17617 APSInt IgnoredVal(DestWidth, !DestSigned);
17618 bool Ignored;
17619 // If the value does not fit in the destination type, the behavior is
17620 // undefined, so we are not required to treat it as a constant
17621 // expression.
17622 if (FL->getValue().convertToInteger(Result&: IgnoredVal,
17623 RM: llvm::APFloat::rmTowardZero,
17624 IsExact: &Ignored) & APFloat::opInvalidOp)
17625 return ICEDiag(IK_NotICE, E->getBeginLoc());
17626 return NoDiag();
17627 }
17628 }
17629 switch (cast<CastExpr>(Val: E)->getCastKind()) {
17630 case CK_LValueToRValue:
17631 case CK_AtomicToNonAtomic:
17632 case CK_NonAtomicToAtomic:
17633 case CK_NoOp:
17634 case CK_IntegralToBoolean:
17635 case CK_IntegralCast:
17636 return CheckICE(E: SubExpr, Ctx);
17637 default:
17638 return ICEDiag(IK_NotICE, E->getBeginLoc());
17639 }
17640 }
17641 case Expr::BinaryConditionalOperatorClass: {
17642 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(Val: E);
17643 ICEDiag CommonResult = CheckICE(E: Exp->getCommon(), Ctx);
17644 if (CommonResult.Kind == IK_NotICE) return CommonResult;
17645 ICEDiag FalseResult = CheckICE(E: Exp->getFalseExpr(), Ctx);
17646 if (FalseResult.Kind == IK_NotICE) return FalseResult;
17647 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
17648 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
17649 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
17650 return FalseResult;
17651 }
17652 case Expr::ConditionalOperatorClass: {
17653 const ConditionalOperator *Exp = cast<ConditionalOperator>(Val: E);
17654 // If the condition (ignoring parens) is a __builtin_constant_p call,
17655 // then only the true side is actually considered in an integer constant
17656 // expression, and it is fully evaluated. This is an important GNU
17657 // extension. See GCC PR38377 for discussion.
17658 if (const CallExpr *CallCE
17659 = dyn_cast<CallExpr>(Val: Exp->getCond()->IgnoreParenCasts()))
17660 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
17661 return CheckEvalInICE(E, Ctx);
17662 ICEDiag CondResult = CheckICE(E: Exp->getCond(), Ctx);
17663 if (CondResult.Kind == IK_NotICE)
17664 return CondResult;
17665
17666 ICEDiag TrueResult = CheckICE(E: Exp->getTrueExpr(), Ctx);
17667 ICEDiag FalseResult = CheckICE(E: Exp->getFalseExpr(), Ctx);
17668
17669 if (TrueResult.Kind == IK_NotICE)
17670 return TrueResult;
17671 if (FalseResult.Kind == IK_NotICE)
17672 return FalseResult;
17673 if (CondResult.Kind == IK_ICEIfUnevaluated)
17674 return CondResult;
17675 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
17676 return NoDiag();
17677 // Rare case where the diagnostics depend on which side is evaluated
17678 // Note that if we get here, CondResult is 0, and at least one of
17679 // TrueResult and FalseResult is non-zero.
17680 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
17681 return FalseResult;
17682 return TrueResult;
17683 }
17684 case Expr::CXXDefaultArgExprClass:
17685 return CheckICE(E: cast<CXXDefaultArgExpr>(Val: E)->getExpr(), Ctx);
17686 case Expr::CXXDefaultInitExprClass:
17687 return CheckICE(E: cast<CXXDefaultInitExpr>(Val: E)->getExpr(), Ctx);
17688 case Expr::ChooseExprClass: {
17689 return CheckICE(E: cast<ChooseExpr>(Val: E)->getChosenSubExpr(), Ctx);
17690 }
17691 case Expr::BuiltinBitCastExprClass: {
17692 if (!checkBitCastConstexprEligibility(Info: nullptr, Ctx, BCE: cast<CastExpr>(Val: E)))
17693 return ICEDiag(IK_NotICE, E->getBeginLoc());
17694 return CheckICE(E: cast<CastExpr>(Val: E)->getSubExpr(), Ctx);
17695 }
17696 }
17697
17698 llvm_unreachable("Invalid StmtClass!");
17699}
17700
17701/// Evaluate an expression as a C++11 integral constant expression.
17702static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
17703 const Expr *E,
17704 llvm::APSInt *Value,
17705 SourceLocation *Loc) {
17706 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
17707 if (Loc) *Loc = E->getExprLoc();
17708 return false;
17709 }
17710
17711 APValue Result;
17712 if (!E->isCXX11ConstantExpr(Ctx, Result: &Result, Loc))
17713 return false;
17714
17715 if (!Result.isInt()) {
17716 if (Loc) *Loc = E->getExprLoc();
17717 return false;
17718 }
17719
17720 if (Value) *Value = Result.getInt();
17721 return true;
17722}
17723
17724bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
17725 SourceLocation *Loc) const {
17726 assert(!isValueDependent() &&
17727 "Expression evaluator can't be called on a dependent expression.");
17728
17729 ExprTimeTraceScope TimeScope(this, Ctx, "isIntegerConstantExpr");
17730
17731 if (Ctx.getLangOpts().CPlusPlus11)
17732 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, E: this, Value: nullptr, Loc);
17733
17734 ICEDiag D = CheckICE(E: this, Ctx);
17735 if (D.Kind != IK_ICE) {
17736 if (Loc) *Loc = D.Loc;
17737 return false;
17738 }
17739 return true;
17740}
17741
17742std::optional<llvm::APSInt>
17743Expr::getIntegerConstantExpr(const ASTContext &Ctx, SourceLocation *Loc) const {
17744 if (isValueDependent()) {
17745 // Expression evaluator can't succeed on a dependent expression.
17746 return std::nullopt;
17747 }
17748
17749 APSInt Value;
17750
17751 if (Ctx.getLangOpts().CPlusPlus11) {
17752 if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, E: this, Value: &Value, Loc))
17753 return Value;
17754 return std::nullopt;
17755 }
17756
17757 if (!isIntegerConstantExpr(Ctx, Loc))
17758 return std::nullopt;
17759
17760 // The only possible side-effects here are due to UB discovered in the
17761 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
17762 // required to treat the expression as an ICE, so we produce the folded
17763 // value.
17764 EvalResult ExprResult;
17765 Expr::EvalStatus Status;
17766 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
17767 Info.InConstantContext = true;
17768
17769 if (!::EvaluateAsInt(E: this, ExprResult, Ctx, AllowSideEffects: SE_AllowSideEffects, Info))
17770 llvm_unreachable("ICE cannot be evaluated!");
17771
17772 return ExprResult.Val.getInt();
17773}
17774
17775bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
17776 assert(!isValueDependent() &&
17777 "Expression evaluator can't be called on a dependent expression.");
17778
17779 return CheckICE(E: this, Ctx).Kind == IK_ICE;
17780}
17781
17782bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
17783 SourceLocation *Loc) const {
17784 assert(!isValueDependent() &&
17785 "Expression evaluator can't be called on a dependent expression.");
17786
17787 // We support this checking in C++98 mode in order to diagnose compatibility
17788 // issues.
17789 assert(Ctx.getLangOpts().CPlusPlus);
17790
17791 // Build evaluation settings.
17792 Expr::EvalStatus Status;
17793 SmallVector<PartialDiagnosticAt, 8> Diags;
17794 Status.Diag = &Diags;
17795 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
17796
17797 APValue Scratch;
17798 bool IsConstExpr =
17799 ::EvaluateAsRValue(Info, E: this, Result&: Result ? *Result : Scratch) &&
17800 // FIXME: We don't produce a diagnostic for this, but the callers that
17801 // call us on arbitrary full-expressions should generally not care.
17802 Info.discardCleanups() && !Status.HasSideEffects;
17803
17804 if (!Diags.empty()) {
17805 IsConstExpr = false;
17806 if (Loc) *Loc = Diags[0].first;
17807 } else if (!IsConstExpr) {
17808 // FIXME: This shouldn't happen.
17809 if (Loc) *Loc = getExprLoc();
17810 }
17811
17812 return IsConstExpr;
17813}
17814
17815bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
17816 const FunctionDecl *Callee,
17817 ArrayRef<const Expr*> Args,
17818 const Expr *This) const {
17819 assert(!isValueDependent() &&
17820 "Expression evaluator can't be called on a dependent expression.");
17821
17822 llvm::TimeTraceScope TimeScope("EvaluateWithSubstitution", [&] {
17823 std::string Name;
17824 llvm::raw_string_ostream OS(Name);
17825 Callee->getNameForDiagnostic(OS, Policy: Ctx.getPrintingPolicy(),
17826 /*Qualified=*/true);
17827 return Name;
17828 });
17829
17830 Expr::EvalStatus Status;
17831 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
17832 Info.InConstantContext = true;
17833
17834 LValue ThisVal;
17835 const LValue *ThisPtr = nullptr;
17836 if (This) {
17837#ifndef NDEBUG
17838 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
17839 assert(MD && "Don't provide `this` for non-methods.");
17840 assert(MD->isImplicitObjectMemberFunction() &&
17841 "Don't provide `this` for methods without an implicit object.");
17842#endif
17843 if (!This->isValueDependent() &&
17844 EvaluateObjectArgument(Info, Object: This, This&: ThisVal) &&
17845 !Info.EvalStatus.HasSideEffects)
17846 ThisPtr = &ThisVal;
17847
17848 // Ignore any side-effects from a failed evaluation. This is safe because
17849 // they can't interfere with any other argument evaluation.
17850 Info.EvalStatus.HasSideEffects = false;
17851 }
17852
17853 CallRef Call = Info.CurrentCall->createCall(Callee);
17854 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
17855 I != E; ++I) {
17856 unsigned Idx = I - Args.begin();
17857 if (Idx >= Callee->getNumParams())
17858 break;
17859 const ParmVarDecl *PVD = Callee->getParamDecl(i: Idx);
17860 if ((*I)->isValueDependent() ||
17861 !EvaluateCallArg(PVD, Arg: *I, Call, Info) ||
17862 Info.EvalStatus.HasSideEffects) {
17863 // If evaluation fails, throw away the argument entirely.
17864 if (APValue *Slot = Info.getParamSlot(Call, PVD))
17865 *Slot = APValue();
17866 }
17867
17868 // Ignore any side-effects from a failed evaluation. This is safe because
17869 // they can't interfere with any other argument evaluation.
17870 Info.EvalStatus.HasSideEffects = false;
17871 }
17872
17873 // Parameter cleanups happen in the caller and are not part of this
17874 // evaluation.
17875 Info.discardCleanups();
17876 Info.EvalStatus.HasSideEffects = false;
17877
17878 // Build fake call to Callee.
17879 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, This,
17880 Call);
17881 // FIXME: Missing ExprWithCleanups in enable_if conditions?
17882 FullExpressionRAII Scope(Info);
17883 return Evaluate(Result&: Value, Info, E: this) && Scope.destroy() &&
17884 !Info.EvalStatus.HasSideEffects;
17885}
17886
17887bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
17888 SmallVectorImpl<
17889 PartialDiagnosticAt> &Diags) {
17890 // FIXME: It would be useful to check constexpr function templates, but at the
17891 // moment the constant expression evaluator cannot cope with the non-rigorous
17892 // ASTs which we build for dependent expressions.
17893 if (FD->isDependentContext())
17894 return true;
17895
17896 llvm::TimeTraceScope TimeScope("isPotentialConstantExpr", [&] {
17897 std::string Name;
17898 llvm::raw_string_ostream OS(Name);
17899 FD->getNameForDiagnostic(OS, Policy: FD->getASTContext().getPrintingPolicy(),
17900 /*Qualified=*/true);
17901 return Name;
17902 });
17903
17904 Expr::EvalStatus Status;
17905 Status.Diag = &Diags;
17906
17907 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
17908 Info.InConstantContext = true;
17909 Info.CheckingPotentialConstantExpression = true;
17910
17911 // The constexpr VM attempts to compile all methods to bytecode here.
17912 if (Info.EnableNewConstInterp) {
17913 Info.Ctx.getInterpContext().isPotentialConstantExpr(Parent&: Info, FnDecl: FD);
17914 return Diags.empty();
17915 }
17916
17917 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: FD);
17918 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
17919
17920 // Fabricate an arbitrary expression on the stack and pretend that it
17921 // is a temporary being used as the 'this' pointer.
17922 LValue This;
17923 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(Decl: RD) : Info.Ctx.IntTy);
17924 This.set(B: {&VIE, Info.CurrentCall->Index});
17925
17926 ArrayRef<const Expr*> Args;
17927
17928 APValue Scratch;
17929 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Val: FD)) {
17930 // Evaluate the call as a constant initializer, to allow the construction
17931 // of objects of non-literal types.
17932 Info.setEvaluatingDecl(Base: This.getLValueBase(), Value&: Scratch);
17933 HandleConstructorCall(E: &VIE, This, Args, Definition: CD, Info, Result&: Scratch);
17934 } else {
17935 SourceLocation Loc = FD->getLocation();
17936 HandleFunctionCall(
17937 CallLoc: Loc, Callee: FD, ObjectArg: (MD && MD->isImplicitObjectMemberFunction()) ? &This : nullptr,
17938 E: &VIE, Args, Call: CallRef(), Body: FD->getBody(), Info, Result&: Scratch,
17939 /*ResultSlot=*/nullptr);
17940 }
17941
17942 return Diags.empty();
17943}
17944
17945bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
17946 const FunctionDecl *FD,
17947 SmallVectorImpl<
17948 PartialDiagnosticAt> &Diags) {
17949 assert(!E->isValueDependent() &&
17950 "Expression evaluator can't be called on a dependent expression.");
17951
17952 Expr::EvalStatus Status;
17953 Status.Diag = &Diags;
17954
17955 EvalInfo Info(FD->getASTContext(), Status,
17956 EvalInfo::EM_ConstantExpressionUnevaluated);
17957 Info.InConstantContext = true;
17958 Info.CheckingPotentialConstantExpression = true;
17959
17960 // Fabricate a call stack frame to give the arguments a plausible cover story.
17961 CallStackFrame Frame(Info, SourceLocation(), FD, /*This=*/nullptr,
17962 /*CallExpr=*/nullptr, CallRef());
17963
17964 APValue ResultScratch;
17965 Evaluate(Result&: ResultScratch, Info, E);
17966 return Diags.empty();
17967}
17968
17969bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
17970 unsigned Type) const {
17971 if (!getType()->isPointerType())
17972 return false;
17973
17974 Expr::EvalStatus Status;
17975 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
17976 return tryEvaluateBuiltinObjectSize(E: this, Type, Info, Size&: Result);
17977}
17978
17979static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result,
17980 EvalInfo &Info, std::string *StringResult) {
17981 if (!E->getType()->hasPointerRepresentation() || !E->isPRValue())
17982 return false;
17983
17984 LValue String;
17985
17986 if (!EvaluatePointer(E, Result&: String, Info))
17987 return false;
17988
17989 QualType CharTy = E->getType()->getPointeeType();
17990
17991 // Fast path: if it's a string literal, search the string value.
17992 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
17993 Val: String.getLValueBase().dyn_cast<const Expr *>())) {
17994 StringRef Str = S->getBytes();
17995 int64_t Off = String.Offset.getQuantity();
17996 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
17997 S->getCharByteWidth() == 1 &&
17998 // FIXME: Add fast-path for wchar_t too.
17999 Info.Ctx.hasSameUnqualifiedType(T1: CharTy, T2: Info.Ctx.CharTy)) {
18000 Str = Str.substr(Start: Off);
18001
18002 StringRef::size_type Pos = Str.find(C: 0);
18003 if (Pos != StringRef::npos)
18004 Str = Str.substr(Start: 0, N: Pos);
18005
18006 Result = Str.size();
18007 if (StringResult)
18008 *StringResult = Str;
18009 return true;
18010 }
18011
18012 // Fall through to slow path.
18013 }
18014
18015 // Slow path: scan the bytes of the string looking for the terminating 0.
18016 for (uint64_t Strlen = 0; /**/; ++Strlen) {
18017 APValue Char;
18018 if (!handleLValueToRValueConversion(Info, Conv: E, Type: CharTy, LVal: String, RVal&: Char) ||
18019 !Char.isInt())
18020 return false;
18021 if (!Char.getInt()) {
18022 Result = Strlen;
18023 return true;
18024 } else if (StringResult)
18025 StringResult->push_back(c: Char.getInt().getExtValue());
18026 if (!HandleLValueArrayAdjustment(Info, E, LVal&: String, EltTy: CharTy, Adjustment: 1))
18027 return false;
18028 }
18029}
18030
18031std::optional<std::string> Expr::tryEvaluateString(ASTContext &Ctx) const {
18032 Expr::EvalStatus Status;
18033 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
18034 uint64_t Result;
18035 std::string StringResult;
18036
18037 if (EvaluateBuiltinStrLen(E: this, Result, Info, StringResult: &StringResult))
18038 return StringResult;
18039 return {};
18040}
18041
18042template <typename T>
18043static bool EvaluateCharRangeAsStringImpl(const Expr *, T &Result,
18044 const Expr *SizeExpression,
18045 const Expr *PtrExpression,
18046 ASTContext &Ctx,
18047 Expr::EvalResult &Status) {
18048 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
18049 Info.InConstantContext = true;
18050
18051 if (Info.EnableNewConstInterp)
18052 return Info.Ctx.getInterpContext().evaluateCharRange(Info, SizeExpression,
18053 PtrExpression, Result);
18054
18055 LValue String;
18056 FullExpressionRAII Scope(Info);
18057 APSInt SizeValue;
18058 if (!::EvaluateInteger(E: SizeExpression, Result&: SizeValue, Info))
18059 return false;
18060
18061 uint64_t Size = SizeValue.getZExtValue();
18062
18063 // FIXME: better protect against invalid or excessive sizes
18064 if constexpr (std::is_same_v<APValue, T>)
18065 Result = APValue(APValue::UninitArray{}, Size, Size);
18066 else {
18067 if (Size < Result.max_size())
18068 Result.reserve(Size);
18069 }
18070 if (!::EvaluatePointer(E: PtrExpression, Result&: String, Info))
18071 return false;
18072
18073 QualType CharTy = PtrExpression->getType()->getPointeeType();
18074 for (uint64_t I = 0; I < Size; ++I) {
18075 APValue Char;
18076 if (!handleLValueToRValueConversion(Info, Conv: PtrExpression, Type: CharTy, LVal: String,
18077 RVal&: Char))
18078 return false;
18079
18080 if constexpr (std::is_same_v<APValue, T>) {
18081 Result.getArrayInitializedElt(I) = std::move(Char);
18082 } else {
18083 APSInt C = Char.getInt();
18084
18085 assert(C.getBitWidth() <= 8 &&
18086 "string element not representable in char");
18087
18088 Result.push_back(static_cast<char>(C.getExtValue()));
18089 }
18090
18091 if (!HandleLValueArrayAdjustment(Info, E: PtrExpression, LVal&: String, EltTy: CharTy, Adjustment: 1))
18092 return false;
18093 }
18094
18095 return Scope.destroy() && CheckMemoryLeaks(Info);
18096}
18097
18098bool Expr::EvaluateCharRangeAsString(std::string &Result,
18099 const Expr *SizeExpression,
18100 const Expr *PtrExpression, ASTContext &Ctx,
18101 EvalResult &Status) const {
18102 return EvaluateCharRangeAsStringImpl(this, Result, SizeExpression,
18103 PtrExpression, Ctx, Status);
18104}
18105
18106bool Expr::EvaluateCharRangeAsString(APValue &Result,
18107 const Expr *SizeExpression,
18108 const Expr *PtrExpression, ASTContext &Ctx,
18109 EvalResult &Status) const {
18110 return EvaluateCharRangeAsStringImpl(this, Result, SizeExpression,
18111 PtrExpression, Ctx, Status);
18112}
18113
18114bool Expr::tryEvaluateStrLen(uint64_t &Result, ASTContext &Ctx) const {
18115 Expr::EvalStatus Status;
18116 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
18117 return EvaluateBuiltinStrLen(E: this, Result, Info);
18118}
18119
18120namespace {
18121struct IsWithinLifetimeHandler {
18122 EvalInfo &Info;
18123 static constexpr AccessKinds AccessKind = AccessKinds::AK_IsWithinLifetime;
18124 using result_type = std::optional<bool>;
18125 std::optional<bool> failed() { return std::nullopt; }
18126 template <typename T>
18127 std::optional<bool> found(T &Subobj, QualType SubobjType) {
18128 return true;
18129 }
18130};
18131
18132std::optional<bool> EvaluateBuiltinIsWithinLifetime(IntExprEvaluator &IEE,
18133 const CallExpr *E) {
18134 EvalInfo &Info = IEE.Info;
18135 // Sometimes this is called during some sorts of constant folding / early
18136 // evaluation. These are meant for non-constant expressions and are not
18137 // necessary since this consteval builtin will never be evaluated at runtime.
18138 // Just fail to evaluate when not in a constant context.
18139 if (!Info.InConstantContext)
18140 return std::nullopt;
18141 assert(E->getBuiltinCallee() == Builtin::BI__builtin_is_within_lifetime);
18142 const Expr *Arg = E->getArg(Arg: 0);
18143 if (Arg->isValueDependent())
18144 return std::nullopt;
18145 LValue Val;
18146 if (!EvaluatePointer(E: Arg, Result&: Val, Info))
18147 return std::nullopt;
18148
18149 if (Val.allowConstexprUnknown())
18150 return true;
18151
18152 auto Error = [&](int Diag) {
18153 bool CalledFromStd = false;
18154 const auto *Callee = Info.CurrentCall->getCallee();
18155 if (Callee && Callee->isInStdNamespace()) {
18156 const IdentifierInfo *Identifier = Callee->getIdentifier();
18157 CalledFromStd = Identifier && Identifier->isStr(Str: "is_within_lifetime");
18158 }
18159 Info.CCEDiag(Loc: CalledFromStd ? Info.CurrentCall->getCallRange().getBegin()
18160 : E->getExprLoc(),
18161 DiagId: diag::err_invalid_is_within_lifetime)
18162 << (CalledFromStd ? "std::is_within_lifetime"
18163 : "__builtin_is_within_lifetime")
18164 << Diag;
18165 return std::nullopt;
18166 };
18167 // C++2c [meta.const.eval]p4:
18168 // During the evaluation of an expression E as a core constant expression, a
18169 // call to this function is ill-formed unless p points to an object that is
18170 // usable in constant expressions or whose complete object's lifetime began
18171 // within E.
18172
18173 // Make sure it points to an object
18174 // nullptr does not point to an object
18175 if (Val.isNullPointer() || Val.getLValueBase().isNull())
18176 return Error(0);
18177 QualType T = Val.getLValueBase().getType();
18178 assert(!T->isFunctionType() &&
18179 "Pointers to functions should have been typed as function pointers "
18180 "which would have been rejected earlier");
18181 assert(T->isObjectType());
18182 // Hypothetical array element is not an object
18183 if (Val.getLValueDesignator().isOnePastTheEnd())
18184 return Error(1);
18185 assert(Val.getLValueDesignator().isValidSubobject() &&
18186 "Unchecked case for valid subobject");
18187 // All other ill-formed values should have failed EvaluatePointer, so the
18188 // object should be a pointer to an object that is usable in a constant
18189 // expression or whose complete lifetime began within the expression
18190 CompleteObject CO =
18191 findCompleteObject(Info, E, AK: AccessKinds::AK_IsWithinLifetime, LVal: Val, LValType: T);
18192 // The lifetime hasn't begun yet if we are still evaluating the
18193 // initializer ([basic.life]p(1.2))
18194 if (Info.EvaluatingDeclValue && CO.Value == Info.EvaluatingDeclValue)
18195 return Error(2);
18196
18197 if (!CO)
18198 return false;
18199 IsWithinLifetimeHandler handler{.Info: Info};
18200 return findSubobject(Info, E, Obj: CO, Sub: Val.getLValueDesignator(), handler);
18201}
18202} // namespace
18203