1//===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===//
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 semantic analysis for cast expressions, including
10// 1) C-style casts like '(int) x'
11// 2) C++ functional casts like 'int(x)'
12// 3) C++ named casts like 'static_cast<int>(x)'
13//
14//===----------------------------------------------------------------------===//
15
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTStructuralEquivalence.h"
18#include "clang/AST/CXXInheritance.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/ExprObjC.h"
21#include "clang/AST/RecordLayout.h"
22#include "clang/Basic/PartialDiagnostic.h"
23#include "clang/Basic/TargetInfo.h"
24#include "clang/Lex/Preprocessor.h"
25#include "clang/Sema/Initialization.h"
26#include "clang/Sema/SemaHLSL.h"
27#include "clang/Sema/SemaObjC.h"
28#include "clang/Sema/SemaRISCV.h"
29#include "llvm/ADT/SmallVector.h"
30#include "llvm/ADT/StringExtras.h"
31#include <set>
32using namespace clang;
33
34
35
36enum TryCastResult {
37 TC_NotApplicable, ///< The cast method is not applicable.
38 TC_Success, ///< The cast method is appropriate and successful.
39 TC_Extension, ///< The cast method is appropriate and accepted as a
40 ///< language extension.
41 TC_Failed ///< The cast method is appropriate, but failed. A
42 ///< diagnostic has been emitted.
43};
44
45static bool isValidCast(TryCastResult TCR) {
46 return TCR == TC_Success || TCR == TC_Extension;
47}
48
49enum CastType {
50 CT_Const, ///< const_cast
51 CT_Static, ///< static_cast
52 CT_Reinterpret, ///< reinterpret_cast
53 CT_Dynamic, ///< dynamic_cast
54 CT_CStyle, ///< (Type)expr
55 CT_Functional, ///< Type(expr)
56 CT_Addrspace ///< addrspace_cast
57};
58
59namespace {
60 struct CastOperation {
61 CastOperation(Sema &S, QualType destType, ExprResult src)
62 : Self(S), SrcExpr(src), DestType(destType),
63 ResultType(destType.getNonLValueExprType(Context: S.Context)),
64 ValueKind(Expr::getValueKindForType(T: destType)),
65 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
66
67 // C++ [expr.type]/8.2.2:
68 // If a pr-value initially has the type cv-T, where T is a
69 // cv-unqualified non-class, non-array type, the type of the
70 // expression is adjusted to T prior to any further analysis.
71 // C23 6.5.4p6:
72 // Preceding an expression by a parenthesized type name converts the
73 // value of the expression to the unqualified, non-atomic version of
74 // the named type.
75 // Don't drop __ptrauth qualifiers. We want to treat casting to a
76 // __ptrauth-qualified type as an error instead of implicitly ignoring
77 // the qualifier.
78 if (!S.Context.getLangOpts().ObjC && !DestType->isRecordType() &&
79 !DestType->isArrayType() && !DestType.getPointerAuth()) {
80 DestType = DestType.getAtomicUnqualifiedType();
81 }
82
83 if (const BuiltinType *placeholder =
84 src.get()->getType()->getAsPlaceholderType()) {
85 PlaceholderKind = placeholder->getKind();
86 } else {
87 PlaceholderKind = (BuiltinType::Kind) 0;
88 }
89 }
90
91 Sema &Self;
92 ExprResult SrcExpr;
93 QualType DestType;
94 QualType ResultType;
95 ExprValueKind ValueKind;
96 CastKind Kind;
97 BuiltinType::Kind PlaceholderKind;
98 CXXCastPath BasePath;
99 bool IsARCUnbridgedCast;
100
101 struct OpRangeType {
102 SourceLocation Locations[3];
103
104 OpRangeType(SourceLocation Begin, SourceLocation LParen,
105 SourceLocation RParen)
106 : Locations{Begin, LParen, RParen} {}
107
108 OpRangeType() = default;
109
110 SourceLocation getBegin() const { return Locations[0]; }
111
112 SourceLocation getLParenLoc() const { return Locations[1]; }
113
114 SourceLocation getRParenLoc() const { return Locations[2]; }
115
116 friend const StreamingDiagnostic &
117 operator<<(const StreamingDiagnostic &DB, OpRangeType Op) {
118 return DB << SourceRange(Op);
119 }
120
121 SourceRange getParenRange() const {
122 return SourceRange(getLParenLoc(), getRParenLoc());
123 }
124
125 operator SourceRange() const {
126 return SourceRange(getBegin(), getRParenLoc());
127 }
128 };
129
130 OpRangeType OpRange;
131 SourceRange DestRange;
132
133 // Top-level semantics-checking routines.
134 void CheckConstCast();
135 void CheckReinterpretCast();
136 void CheckStaticCast();
137 void CheckDynamicCast();
138 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
139 bool CheckHLSLCStyleCast(CheckedConversionKind CCK);
140 void CheckCStyleCast();
141 void CheckBuiltinBitCast();
142 void CheckAddrspaceCast();
143
144 void updatePartOfExplicitCastFlags(CastExpr *CE) {
145 // Walk down from the CE to the OrigSrcExpr, and mark all immediate
146 // ImplicitCastExpr's as being part of ExplicitCastExpr. The original CE
147 // (which is a ExplicitCastExpr), and the OrigSrcExpr are not touched.
148 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Val: CE->getSubExpr()); CE = ICE)
149 ICE->setIsPartOfExplicitCast(true);
150 }
151
152 /// Complete an apparently-successful cast operation that yields
153 /// the given expression.
154 ExprResult complete(CastExpr *castExpr) {
155 // If this is an unbridged cast, wrap the result in an implicit
156 // cast that yields the unbridged-cast placeholder type.
157 if (IsARCUnbridgedCast) {
158 castExpr = ImplicitCastExpr::Create(
159 Context: Self.Context, T: Self.Context.ARCUnbridgedCastTy, Kind: CK_Dependent,
160 Operand: castExpr, BasePath: nullptr, Cat: castExpr->getValueKind(),
161 FPO: Self.CurFPFeatureOverrides());
162 }
163 updatePartOfExplicitCastFlags(CE: castExpr);
164 return castExpr;
165 }
166
167 // Internal convenience methods.
168
169 /// Try to handle the given placeholder expression kind. Return
170 /// true if the source expression has the appropriate placeholder
171 /// kind. A placeholder can only be claimed once.
172 bool claimPlaceholder(BuiltinType::Kind K) {
173 if (PlaceholderKind != K) return false;
174
175 PlaceholderKind = (BuiltinType::Kind) 0;
176 return true;
177 }
178
179 bool isPlaceholder() const {
180 return PlaceholderKind != 0;
181 }
182 bool isPlaceholder(BuiltinType::Kind K) const {
183 return PlaceholderKind == K;
184 }
185
186 // Language specific cast restrictions for address spaces.
187 void checkAddressSpaceCast(QualType SrcType, QualType DestType);
188
189 void checkCastAlign() {
190 Self.CheckCastAlign(Op: SrcExpr.get(), T: DestType, TRange: OpRange);
191 }
192
193 void checkObjCConversion(CheckedConversionKind CCK,
194 bool IsReinterpretCast = false) {
195 assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
196
197 Expr *src = SrcExpr.get();
198 if (Self.ObjC().CheckObjCConversion(
199 castRange: OpRange, castType: DestType, op&: src, CCK, Diagnose: true, DiagnoseCFAudited: false, Opc: BO_PtrMemD,
200 IsReinterpretCast) == SemaObjC::ACR_unbridged)
201 IsARCUnbridgedCast = true;
202 SrcExpr = src;
203 }
204
205 void checkQualifiedDestType() {
206 // Destination type may not be qualified with __ptrauth.
207 if (DestType.getPointerAuth()) {
208 Self.Diag(Loc: DestRange.getBegin(), DiagID: diag::err_ptrauth_qualifier_cast)
209 << DestType << DestRange;
210 }
211 }
212
213 /// Check for and handle non-overload placeholder expressions.
214 void checkNonOverloadPlaceholders() {
215 if (!isPlaceholder() || isPlaceholder(K: BuiltinType::Overload))
216 return;
217
218 SrcExpr = Self.CheckPlaceholderExpr(E: SrcExpr.get());
219 if (SrcExpr.isInvalid())
220 return;
221 PlaceholderKind = (BuiltinType::Kind) 0;
222 }
223 };
224
225 void CheckNoDeref(Sema &S, const QualType FromType, const QualType ToType,
226 SourceLocation OpLoc) {
227 if (const auto *PtrType = dyn_cast<PointerType>(Val: FromType)) {
228 if (PtrType->getPointeeType()->hasAttr(AK: attr::NoDeref)) {
229 if (const auto *DestType = dyn_cast<PointerType>(Val: ToType)) {
230 if (!DestType->getPointeeType()->hasAttr(AK: attr::NoDeref)) {
231 S.Diag(Loc: OpLoc, DiagID: diag::warn_noderef_to_dereferenceable_pointer);
232 }
233 }
234 }
235 }
236 }
237
238 struct CheckNoDerefRAII {
239 CheckNoDerefRAII(CastOperation &Op) : Op(Op) {}
240 ~CheckNoDerefRAII() {
241 if (!Op.SrcExpr.isInvalid())
242 CheckNoDeref(S&: Op.Self, FromType: Op.SrcExpr.get()->getType(), ToType: Op.ResultType,
243 OpLoc: Op.OpRange.getBegin());
244 }
245
246 CastOperation &Op;
247 };
248}
249
250static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
251 QualType DestType);
252
253// The Try functions attempt a specific way of casting. If they succeed, they
254// return TC_Success. If their way of casting is not appropriate for the given
255// arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
256// to emit if no other way succeeds. If their way of casting is appropriate but
257// fails, they return TC_Failed and *must* set diag; they can set it to 0 if
258// they emit a specialized diagnostic.
259// All diagnostics returned by these functions must expect the same three
260// arguments:
261// %0: Cast Type (a value from the CastType enumeration)
262// %1: Source Type
263// %2: Destination Type
264static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
265 QualType DestType, bool CStyle,
266 SourceRange OpRange, CastKind &Kind,
267 CXXCastPath &BasePath,
268 unsigned &msg);
269static TryCastResult
270TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
271 bool CStyle, CastOperation::OpRangeType OpRange,
272 unsigned &msg, CastKind &Kind,
273 CXXCastPath &BasePath);
274static TryCastResult
275TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
276 bool CStyle, CastOperation::OpRangeType OpRange,
277 unsigned &msg, CastKind &Kind, CXXCastPath &BasePath);
278static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
279 CanQualType DestType, bool CStyle,
280 CastOperation::OpRangeType OpRange,
281 QualType OrigSrcType,
282 QualType OrigDestType, unsigned &msg,
283 CastKind &Kind, CXXCastPath &BasePath);
284static TryCastResult
285TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
286 QualType DestType, bool CStyle,
287 CastOperation::OpRangeType OpRange, unsigned &msg,
288 CastKind &Kind, CXXCastPath &BasePath);
289
290static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
291 QualType DestType,
292 CheckedConversionKind CCK,
293 CastOperation::OpRangeType OpRange,
294 unsigned &msg, CastKind &Kind,
295 bool ListInitialization);
296static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
297 QualType DestType, CheckedConversionKind CCK,
298 CastOperation::OpRangeType OpRange,
299 unsigned &msg, CastKind &Kind,
300 CXXCastPath &BasePath,
301 bool ListInitialization);
302static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
303 QualType DestType, bool CStyle,
304 unsigned &msg);
305static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
306 QualType DestType, bool CStyle,
307 CastOperation::OpRangeType OpRange,
308 unsigned &msg, CastKind &Kind);
309static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
310 QualType DestType, bool CStyle,
311 unsigned &msg, CastKind &Kind);
312
313ExprResult
314Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
315 SourceLocation LAngleBracketLoc, Declarator &D,
316 SourceLocation RAngleBracketLoc,
317 SourceLocation LParenLoc, Expr *E,
318 SourceLocation RParenLoc) {
319
320 assert(!D.isInvalidType());
321
322 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, FromTy: E->getType());
323 if (D.isInvalidType())
324 return ExprError();
325
326 if (getLangOpts().CPlusPlus) {
327 // Check that there are no default arguments (C++ only).
328 CheckExtraCXXDefaultArguments(D);
329 }
330
331 return BuildCXXNamedCast(OpLoc, Kind, Ty: TInfo, E,
332 AngleBrackets: SourceRange(LAngleBracketLoc, RAngleBracketLoc),
333 Parens: SourceRange(LParenLoc, RParenLoc));
334}
335
336ExprResult
337Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
338 TypeSourceInfo *DestTInfo, Expr *E,
339 SourceRange AngleBrackets, SourceRange Parens) {
340 ExprResult Ex = E;
341 QualType DestType = DestTInfo->getType();
342
343 // If the type is dependent, we won't do the semantic analysis now.
344 bool TypeDependent =
345 DestType->isDependentType() || Ex.get()->isTypeDependent();
346
347 CastOperation Op(*this, DestType, E);
348 Op.OpRange =
349 CastOperation::OpRangeType(OpLoc, Parens.getBegin(), Parens.getEnd());
350 Op.DestRange = AngleBrackets;
351
352 Op.checkQualifiedDestType();
353
354 switch (Kind) {
355 default: llvm_unreachable("Unknown C++ cast!");
356
357 case tok::kw_addrspace_cast:
358 if (!TypeDependent) {
359 Op.CheckAddrspaceCast();
360 if (Op.SrcExpr.isInvalid())
361 return ExprError();
362 }
363 return Op.complete(castExpr: CXXAddrspaceCastExpr::Create(
364 Context, T: Op.ResultType, VK: Op.ValueKind, Kind: Op.Kind, Op: Op.SrcExpr.get(),
365 WrittenTy: DestTInfo, L: OpLoc, RParenLoc: Parens.getEnd(), AngleBrackets));
366
367 case tok::kw_const_cast:
368 if (!TypeDependent) {
369 Op.CheckConstCast();
370 if (Op.SrcExpr.isInvalid())
371 return ExprError();
372 DiscardMisalignedMemberAddress(T: DestType.getTypePtr(), E);
373 }
374 return Op.complete(castExpr: CXXConstCastExpr::Create(Context, T: Op.ResultType,
375 VK: Op.ValueKind, Op: Op.SrcExpr.get(), WrittenTy: DestTInfo,
376 L: OpLoc, RParenLoc: Parens.getEnd(),
377 AngleBrackets));
378
379 case tok::kw_dynamic_cast: {
380 // dynamic_cast is not supported in C++ for OpenCL.
381 if (getLangOpts().OpenCLCPlusPlus) {
382 return ExprError(Diag(Loc: OpLoc, DiagID: diag::err_openclcxx_not_supported)
383 << "dynamic_cast");
384 }
385
386 if (!TypeDependent) {
387 Op.CheckDynamicCast();
388 if (Op.SrcExpr.isInvalid())
389 return ExprError();
390 }
391 return Op.complete(castExpr: CXXDynamicCastExpr::Create(Context, T: Op.ResultType,
392 VK: Op.ValueKind, Kind: Op.Kind, Op: Op.SrcExpr.get(),
393 Path: &Op.BasePath, Written: DestTInfo,
394 L: OpLoc, RParenLoc: Parens.getEnd(),
395 AngleBrackets));
396 }
397 case tok::kw_reinterpret_cast: {
398 if (!TypeDependent) {
399 Op.CheckReinterpretCast();
400 if (Op.SrcExpr.isInvalid())
401 return ExprError();
402 DiscardMisalignedMemberAddress(T: DestType.getTypePtr(), E);
403 }
404 return Op.complete(castExpr: CXXReinterpretCastExpr::Create(Context, T: Op.ResultType,
405 VK: Op.ValueKind, Kind: Op.Kind, Op: Op.SrcExpr.get(),
406 Path: nullptr, WrittenTy: DestTInfo, L: OpLoc,
407 RParenLoc: Parens.getEnd(),
408 AngleBrackets));
409 }
410 case tok::kw_static_cast: {
411 if (!TypeDependent) {
412 Op.CheckStaticCast();
413 if (Op.SrcExpr.isInvalid())
414 return ExprError();
415 DiscardMisalignedMemberAddress(T: DestType.getTypePtr(), E);
416 }
417
418 return Op.complete(castExpr: CXXStaticCastExpr::Create(
419 Context, T: Op.ResultType, VK: Op.ValueKind, K: Op.Kind, Op: Op.SrcExpr.get(),
420 Path: &Op.BasePath, Written: DestTInfo, FPO: CurFPFeatureOverrides(), L: OpLoc,
421 RParenLoc: Parens.getEnd(), AngleBrackets));
422 }
423 }
424}
425
426ExprResult Sema::ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &D,
427 ExprResult Operand,
428 SourceLocation RParenLoc) {
429 assert(!D.isInvalidType());
430
431 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, FromTy: Operand.get()->getType());
432 if (D.isInvalidType())
433 return ExprError();
434
435 return BuildBuiltinBitCastExpr(KWLoc, TSI: TInfo, Operand: Operand.get(), RParenLoc);
436}
437
438ExprResult Sema::BuildBuiltinBitCastExpr(SourceLocation KWLoc,
439 TypeSourceInfo *TSI, Expr *Operand,
440 SourceLocation RParenLoc) {
441 CastOperation Op(*this, TSI->getType(), Operand);
442 Op.OpRange = CastOperation::OpRangeType(KWLoc, KWLoc, RParenLoc);
443 TypeLoc TL = TSI->getTypeLoc();
444 Op.DestRange = SourceRange(TL.getBeginLoc(), TL.getEndLoc());
445
446 if (!Operand->isTypeDependent() && !TSI->getType()->isDependentType()) {
447 Op.CheckBuiltinBitCast();
448 if (Op.SrcExpr.isInvalid())
449 return ExprError();
450 }
451
452 BuiltinBitCastExpr *BCE =
453 new (Context) BuiltinBitCastExpr(Op.ResultType, Op.ValueKind, Op.Kind,
454 Op.SrcExpr.get(), TSI, KWLoc, RParenLoc);
455 return Op.complete(castExpr: BCE);
456}
457
458/// Try to diagnose a failed overloaded cast. Returns true if
459/// diagnostics were emitted.
460static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
461 CastOperation::OpRangeType range,
462 Expr *src, QualType destType,
463 bool listInitialization) {
464 switch (CT) {
465 // These cast kinds don't consider user-defined conversions.
466 case CT_Const:
467 case CT_Reinterpret:
468 case CT_Dynamic:
469 case CT_Addrspace:
470 return false;
471
472 // These do.
473 case CT_Static:
474 case CT_CStyle:
475 case CT_Functional:
476 break;
477 }
478
479 QualType srcType = src->getType();
480 if (!destType->isRecordType() && !srcType->isRecordType())
481 return false;
482
483 InitializedEntity entity = InitializedEntity::InitializeTemporary(Type: destType);
484 InitializationKind initKind =
485 (CT == CT_CStyle) ? InitializationKind::CreateCStyleCast(
486 StartLoc: range.getBegin(), TypeRange: range, InitList: listInitialization)
487 : (CT == CT_Functional)
488 ? InitializationKind::CreateFunctionalCast(
489 StartLoc: range.getBegin(), ParenRange: range.getParenRange(), InitList: listInitialization)
490 : InitializationKind::CreateCast(/*type range?*/ TypeRange: range);
491 InitializationSequence sequence(S, entity, initKind, src);
492
493 // It could happen that a constructor failed to be used because
494 // it requires a temporary of a broken type. Still, it will be found when
495 // looking for a match.
496 if (!sequence.Failed())
497 return false;
498
499 switch (sequence.getFailureKind()) {
500 default: return false;
501
502 case InitializationSequence::FK_ParenthesizedListInitFailed:
503 // In C++20, if the underlying destination type is a RecordType, Clang
504 // attempts to perform parentesized aggregate initialization if constructor
505 // overload fails:
506 //
507 // C++20 [expr.static.cast]p4:
508 // An expression E can be explicitly converted to a type T...if overload
509 // resolution for a direct-initialization...would find at least one viable
510 // function ([over.match.viable]), or if T is an aggregate type having a
511 // first element X and there is an implicit conversion sequence from E to
512 // the type of X.
513 //
514 // If that fails, then we'll generate the diagnostics from the failed
515 // previous constructor overload attempt. Array initialization, however, is
516 // not done after attempting constructor overloading, so we exit as there
517 // won't be a failed overload result.
518 if (destType->isArrayType())
519 return false;
520 break;
521 case InitializationSequence::FK_ConstructorOverloadFailed:
522 case InitializationSequence::FK_UserConversionOverloadFailed:
523 break;
524 }
525
526 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
527
528 unsigned msg = 0;
529 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
530
531 switch (sequence.getFailedOverloadResult()) {
532 case OR_Success: llvm_unreachable("successful failed overload");
533 case OR_No_Viable_Function:
534 if (candidates.empty())
535 msg = diag::err_ovl_no_conversion_in_cast;
536 else
537 msg = diag::err_ovl_no_viable_conversion_in_cast;
538 howManyCandidates = OCD_AllCandidates;
539 break;
540
541 case OR_Ambiguous:
542 msg = diag::err_ovl_ambiguous_conversion_in_cast;
543 howManyCandidates = OCD_AmbiguousCandidates;
544 break;
545
546 case OR_Deleted: {
547 OverloadCandidateSet::iterator Best;
548 [[maybe_unused]] OverloadingResult Res =
549 candidates.BestViableFunction(S, Loc: range.getBegin(), Best);
550 assert(Res == OR_Deleted && "Inconsistent overload resolution");
551
552 StringLiteral *Msg = Best->Function->getDeletedMessage();
553 candidates.NoteCandidates(
554 PA: PartialDiagnosticAt(range.getBegin(),
555 S.PDiag(DiagID: diag::err_ovl_deleted_conversion_in_cast)
556 << CT << srcType << destType << (Msg != nullptr)
557 << (Msg ? Msg->getString() : StringRef())
558 << range << src->getSourceRange()),
559 S, OCD: OCD_ViableCandidates, Args: src);
560 return true;
561 }
562 }
563
564 candidates.NoteCandidates(
565 PA: PartialDiagnosticAt(range.getBegin(),
566 S.PDiag(DiagID: msg) << CT << srcType << destType << range
567 << src->getSourceRange()),
568 S, OCD: howManyCandidates, Args: src);
569
570 return true;
571}
572
573/// Diagnose a failed cast.
574static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
575 CastOperation::OpRangeType opRange, Expr *src,
576 QualType destType, bool listInitialization) {
577 if (msg == diag::err_bad_cxx_cast_generic &&
578 tryDiagnoseOverloadedCast(S, CT: castType, range: opRange, src, destType,
579 listInitialization))
580 return;
581
582 S.Diag(Loc: opRange.getBegin(), DiagID: msg) << castType
583 << src->getType() << destType << opRange << src->getSourceRange();
584
585 // Detect if both types are (ptr to) class, and note any incompleteness.
586 int DifferentPtrness = 0;
587 QualType From = destType;
588 if (auto Ptr = From->getAs<PointerType>()) {
589 From = Ptr->getPointeeType();
590 DifferentPtrness++;
591 }
592 QualType To = src->getType();
593 if (auto Ptr = To->getAs<PointerType>()) {
594 To = Ptr->getPointeeType();
595 DifferentPtrness--;
596 }
597 if (!DifferentPtrness) {
598 if (auto *DeclFrom = From->getAsCXXRecordDecl(),
599 *DeclTo = To->getAsCXXRecordDecl();
600 DeclFrom && DeclTo) {
601 if (!DeclFrom->isCompleteDefinition())
602 S.Diag(Loc: DeclFrom->getLocation(), DiagID: diag::note_type_incomplete) << DeclFrom;
603 if (!DeclTo->isCompleteDefinition())
604 S.Diag(Loc: DeclTo->getLocation(), DiagID: diag::note_type_incomplete) << DeclTo;
605 }
606 }
607}
608
609namespace {
610/// The kind of unwrapping we did when determining whether a conversion casts
611/// away constness.
612enum CastAwayConstnessKind {
613 /// The conversion does not cast away constness.
614 CACK_None = 0,
615 /// We unwrapped similar types.
616 CACK_Similar = 1,
617 /// We unwrapped dissimilar types with similar representations (eg, a pointer
618 /// versus an Objective-C object pointer).
619 CACK_SimilarKind = 2,
620 /// We unwrapped representationally-unrelated types, such as a pointer versus
621 /// a pointer-to-member.
622 CACK_Incoherent = 3,
623};
624}
625
626/// Unwrap one level of types for CastsAwayConstness.
627///
628/// Like Sema::UnwrapSimilarTypes, this removes one level of indirection from
629/// both types, provided that they're both pointer-like or array-like. Unlike
630/// the Sema function, doesn't care if the unwrapped pieces are related.
631///
632/// This function may remove additional levels as necessary for correctness:
633/// the resulting T1 is unwrapped sufficiently that it is never an array type,
634/// so that its qualifiers can be directly compared to those of T2 (which will
635/// have the combined set of qualifiers from all indermediate levels of T2),
636/// as (effectively) required by [expr.const.cast]p7 replacing T1's qualifiers
637/// with those from T2.
638static CastAwayConstnessKind
639unwrapCastAwayConstnessLevel(ASTContext &Context, QualType &T1, QualType &T2) {
640 enum { None, Ptr, MemPtr, BlockPtr, Array };
641 auto Classify = [](QualType T) {
642 if (T->isAnyPointerType()) return Ptr;
643 if (T->isMemberPointerType()) return MemPtr;
644 if (T->isBlockPointerType()) return BlockPtr;
645 // We somewhat-arbitrarily don't look through VLA types here. This is at
646 // least consistent with the behavior of UnwrapSimilarTypes.
647 if (T->isConstantArrayType() || T->isIncompleteArrayType()) return Array;
648 return None;
649 };
650
651 auto Unwrap = [&](QualType T) {
652 if (auto *AT = Context.getAsArrayType(T))
653 return AT->getElementType();
654 return T->getPointeeType();
655 };
656
657 CastAwayConstnessKind Kind;
658
659 if (T2->isReferenceType()) {
660 // Special case: if the destination type is a reference type, unwrap it as
661 // the first level. (The source will have been an lvalue expression in this
662 // case, so there is no corresponding "reference to" in T1 to remove.) This
663 // simulates removing a "pointer to" from both sides.
664 T2 = T2->getPointeeType();
665 Kind = CastAwayConstnessKind::CACK_Similar;
666 } else if (Context.UnwrapSimilarTypes(T1, T2)) {
667 Kind = CastAwayConstnessKind::CACK_Similar;
668 } else {
669 // Try unwrapping mismatching levels.
670 int T1Class = Classify(T1);
671 if (T1Class == None)
672 return CastAwayConstnessKind::CACK_None;
673
674 int T2Class = Classify(T2);
675 if (T2Class == None)
676 return CastAwayConstnessKind::CACK_None;
677
678 T1 = Unwrap(T1);
679 T2 = Unwrap(T2);
680 Kind = T1Class == T2Class ? CastAwayConstnessKind::CACK_SimilarKind
681 : CastAwayConstnessKind::CACK_Incoherent;
682 }
683
684 // We've unwrapped at least one level. If the resulting T1 is a (possibly
685 // multidimensional) array type, any qualifier on any matching layer of
686 // T2 is considered to correspond to T1. Decompose down to the element
687 // type of T1 so that we can compare properly.
688 while (true) {
689 Context.UnwrapSimilarArrayTypes(T1, T2);
690
691 if (Classify(T1) != Array)
692 break;
693
694 auto T2Class = Classify(T2);
695 if (T2Class == None)
696 break;
697
698 if (T2Class != Array)
699 Kind = CastAwayConstnessKind::CACK_Incoherent;
700 else if (Kind != CastAwayConstnessKind::CACK_Incoherent)
701 Kind = CastAwayConstnessKind::CACK_SimilarKind;
702
703 T1 = Unwrap(T1);
704 T2 = Unwrap(T2).withCVRQualifiers(CVR: T2.getCVRQualifiers());
705 }
706
707 return Kind;
708}
709
710/// Check if the pointer conversion from SrcType to DestType casts away
711/// constness as defined in C++ [expr.const.cast]. This is used by the cast
712/// checkers. Both arguments must denote pointer (possibly to member) types.
713///
714/// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
715/// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
716static CastAwayConstnessKind
717CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
718 bool CheckCVR, bool CheckObjCLifetime,
719 QualType *TheOffendingSrcType = nullptr,
720 QualType *TheOffendingDestType = nullptr,
721 Qualifiers *CastAwayQualifiers = nullptr) {
722 // If the only checking we care about is for Objective-C lifetime qualifiers,
723 // and we're not in ObjC mode, there's nothing to check.
724 if (!CheckCVR && CheckObjCLifetime && !Self.Context.getLangOpts().ObjC)
725 return CastAwayConstnessKind::CACK_None;
726
727 if (!DestType->isReferenceType()) {
728 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
729 SrcType->isBlockPointerType()) &&
730 "Source type is not pointer or pointer to member.");
731 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
732 DestType->isBlockPointerType()) &&
733 "Destination type is not pointer or pointer to member.");
734 }
735
736 QualType UnwrappedSrcType = Self.Context.getCanonicalType(T: SrcType),
737 UnwrappedDestType = Self.Context.getCanonicalType(T: DestType);
738
739 // Find the qualifiers. We only care about cvr-qualifiers for the
740 // purpose of this check, because other qualifiers (address spaces,
741 // Objective-C GC, etc.) are part of the type's identity.
742 QualType PrevUnwrappedSrcType = UnwrappedSrcType;
743 QualType PrevUnwrappedDestType = UnwrappedDestType;
744 auto WorstKind = CastAwayConstnessKind::CACK_Similar;
745 bool AllConstSoFar = true;
746 while (auto Kind = unwrapCastAwayConstnessLevel(
747 Context&: Self.Context, T1&: UnwrappedSrcType, T2&: UnwrappedDestType)) {
748 // Track the worst kind of unwrap we needed to do before we found a
749 // problem.
750 if (Kind > WorstKind)
751 WorstKind = Kind;
752
753 // Determine the relevant qualifiers at this level.
754 Qualifiers SrcQuals, DestQuals;
755 Self.Context.getUnqualifiedArrayType(T: UnwrappedSrcType, Quals&: SrcQuals);
756 Self.Context.getUnqualifiedArrayType(T: UnwrappedDestType, Quals&: DestQuals);
757
758 // We do not meaningfully track object const-ness of Objective-C object
759 // types. Remove const from the source type if either the source or
760 // the destination is an Objective-C object type.
761 if (UnwrappedSrcType->isObjCObjectType() ||
762 UnwrappedDestType->isObjCObjectType())
763 SrcQuals.removeConst();
764
765 if (CheckCVR) {
766 Qualifiers SrcCvrQuals =
767 Qualifiers::fromCVRMask(CVR: SrcQuals.getCVRQualifiers());
768 Qualifiers DestCvrQuals =
769 Qualifiers::fromCVRMask(CVR: DestQuals.getCVRQualifiers());
770
771 if (SrcCvrQuals != DestCvrQuals) {
772 if (CastAwayQualifiers)
773 *CastAwayQualifiers = SrcCvrQuals - DestCvrQuals;
774
775 // If we removed a cvr-qualifier, this is casting away 'constness'.
776 if (!DestCvrQuals.compatiblyIncludes(other: SrcCvrQuals,
777 Ctx: Self.getASTContext())) {
778 if (TheOffendingSrcType)
779 *TheOffendingSrcType = PrevUnwrappedSrcType;
780 if (TheOffendingDestType)
781 *TheOffendingDestType = PrevUnwrappedDestType;
782 return WorstKind;
783 }
784
785 // If any prior level was not 'const', this is also casting away
786 // 'constness'. We noted the outermost type missing a 'const' already.
787 if (!AllConstSoFar)
788 return WorstKind;
789 }
790 }
791
792 if (CheckObjCLifetime &&
793 !DestQuals.compatiblyIncludesObjCLifetime(other: SrcQuals))
794 return WorstKind;
795
796 // If we found our first non-const-qualified type, this may be the place
797 // where things start to go wrong.
798 if (AllConstSoFar && !DestQuals.hasConst()) {
799 AllConstSoFar = false;
800 if (TheOffendingSrcType)
801 *TheOffendingSrcType = PrevUnwrappedSrcType;
802 if (TheOffendingDestType)
803 *TheOffendingDestType = PrevUnwrappedDestType;
804 }
805
806 PrevUnwrappedSrcType = UnwrappedSrcType;
807 PrevUnwrappedDestType = UnwrappedDestType;
808 }
809
810 return CastAwayConstnessKind::CACK_None;
811}
812
813static TryCastResult getCastAwayConstnessCastKind(CastAwayConstnessKind CACK,
814 unsigned &DiagID) {
815 switch (CACK) {
816 case CastAwayConstnessKind::CACK_None:
817 llvm_unreachable("did not cast away constness");
818
819 case CastAwayConstnessKind::CACK_Similar:
820 // FIXME: Accept these as an extension too?
821 case CastAwayConstnessKind::CACK_SimilarKind:
822 DiagID = diag::err_bad_cxx_cast_qualifiers_away;
823 return TC_Failed;
824
825 case CastAwayConstnessKind::CACK_Incoherent:
826 DiagID = diag::ext_bad_cxx_cast_qualifiers_away_incoherent;
827 return TC_Extension;
828 }
829
830 llvm_unreachable("unexpected cast away constness kind");
831}
832
833/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
834/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
835/// checked downcasts in class hierarchies.
836void CastOperation::CheckDynamicCast() {
837 CheckNoDerefRAII NoderefCheck(*this);
838
839 if (ValueKind == VK_PRValue)
840 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
841 else if (isPlaceholder())
842 SrcExpr = Self.CheckPlaceholderExpr(E: SrcExpr.get());
843 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
844 return;
845
846 QualType OrigSrcType = SrcExpr.get()->getType();
847 QualType DestType = Self.Context.getCanonicalType(T: this->DestType);
848
849 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
850 // or "pointer to cv void".
851
852 QualType DestPointee;
853 const PointerType *DestPointer = DestType->getAs<PointerType>();
854 const ReferenceType *DestReference = nullptr;
855 if (DestPointer) {
856 DestPointee = DestPointer->getPointeeType();
857 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
858 DestPointee = DestReference->getPointeeType();
859 } else {
860 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_dynamic_cast_not_ref_or_ptr)
861 << this->DestType << DestRange;
862 SrcExpr = ExprError();
863 return;
864 }
865
866 const auto *DestRecord = DestPointee->getAsCanonical<RecordType>();
867 if (DestPointee->isVoidType()) {
868 assert(DestPointer && "Reference to void is not possible");
869 } else if (DestRecord) {
870 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: DestPointee,
871 DiagID: diag::err_bad_cast_incomplete,
872 Args: DestRange)) {
873 SrcExpr = ExprError();
874 return;
875 }
876 } else {
877 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_dynamic_cast_not_class)
878 << DestPointee.getUnqualifiedType() << DestRange;
879 SrcExpr = ExprError();
880 return;
881 }
882
883 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
884 // complete class type, [...]. If T is an lvalue reference type, v shall be
885 // an lvalue of a complete class type, [...]. If T is an rvalue reference
886 // type, v shall be an expression having a complete class type, [...]
887 QualType SrcType = Self.Context.getCanonicalType(T: OrigSrcType);
888 QualType SrcPointee;
889 if (DestPointer) {
890 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
891 SrcPointee = SrcPointer->getPointeeType();
892 } else {
893 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_dynamic_cast_not_ptr)
894 << OrigSrcType << this->DestType << SrcExpr.get()->getSourceRange();
895 SrcExpr = ExprError();
896 return;
897 }
898 } else if (DestReference->isLValueReferenceType()) {
899 if (!SrcExpr.get()->isLValue()) {
900 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_cxx_cast_rvalue)
901 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
902 }
903 SrcPointee = SrcType;
904 } else {
905 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
906 // to materialize the prvalue before we bind the reference to it.
907 if (SrcExpr.get()->isPRValue())
908 SrcExpr = Self.CreateMaterializeTemporaryExpr(
909 T: SrcType, Temporary: SrcExpr.get(), /*IsLValueReference*/ BoundToLvalueReference: false);
910 SrcPointee = SrcType;
911 }
912
913 const auto *SrcRecord = SrcPointee->getAsCanonical<RecordType>();
914 if (SrcRecord) {
915 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: SrcPointee,
916 DiagID: diag::err_bad_cast_incomplete,
917 Args: SrcExpr.get())) {
918 SrcExpr = ExprError();
919 return;
920 }
921 } else {
922 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_dynamic_cast_not_class)
923 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
924 SrcExpr = ExprError();
925 return;
926 }
927
928 assert((DestPointer || DestReference) &&
929 "Bad destination non-ptr/ref slipped through.");
930 assert((DestRecord || DestPointee->isVoidType()) &&
931 "Bad destination pointee slipped through.");
932 assert(SrcRecord && "Bad source pointee slipped through.");
933
934 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
935 if (!DestPointee.isAtLeastAsQualifiedAs(other: SrcPointee, Ctx: Self.getASTContext())) {
936 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_cxx_cast_qualifiers_away)
937 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
938 SrcExpr = ExprError();
939 return;
940 }
941
942 // C++ 5.2.7p3: If the type of v is the same as the required result type,
943 // [except for cv].
944 if (DestRecord == SrcRecord) {
945 Kind = CK_NoOp;
946 return;
947 }
948
949 // C++ 5.2.7p5
950 // Upcasts are resolved statically.
951 if (DestRecord &&
952 Self.IsDerivedFrom(Loc: OpRange.getBegin(), Derived: SrcPointee, Base: DestPointee)) {
953 if (Self.CheckDerivedToBaseConversion(Derived: SrcPointee, Base: DestPointee,
954 Loc: OpRange.getBegin(), Range: OpRange,
955 BasePath: &BasePath)) {
956 SrcExpr = ExprError();
957 return;
958 }
959
960 Kind = CK_DerivedToBase;
961 return;
962 }
963
964 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
965 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
966 assert(SrcDecl && "Definition missing");
967 if (!cast<CXXRecordDecl>(Val: SrcDecl)->isPolymorphic()) {
968 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_dynamic_cast_not_polymorphic)
969 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
970 SrcExpr = ExprError();
971 }
972
973 // dynamic_cast is not available with -fno-rtti.
974 // As an exception, dynamic_cast to void* is available because it doesn't
975 // use RTTI.
976 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
977 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_no_dynamic_cast_with_fno_rtti);
978 SrcExpr = ExprError();
979 return;
980 }
981
982 // Warns when dynamic_cast is used with RTTI data disabled.
983 if (!Self.getLangOpts().RTTIData) {
984 bool MicrosoftABI =
985 Self.getASTContext().getTargetInfo().getCXXABI().isMicrosoft();
986 bool isClangCL = Self.getDiagnostics().getDiagnosticOptions().getFormat() ==
987 DiagnosticOptions::MSVC;
988 if (MicrosoftABI || !DestPointee->isVoidType())
989 Self.Diag(Loc: OpRange.getBegin(),
990 DiagID: diag::warn_no_dynamic_cast_with_rtti_disabled)
991 << isClangCL;
992 }
993
994 // For a dynamic_cast to a final type, IR generation might emit a reference
995 // to the vtable.
996 if (DestRecord) {
997 auto *DestDecl = DestRecord->getAsCXXRecordDecl();
998 if (DestDecl->isEffectivelyFinal())
999 Self.MarkVTableUsed(Loc: OpRange.getBegin(), Class: DestDecl);
1000 }
1001
1002 // Done. Everything else is run-time checks.
1003 Kind = CK_Dynamic;
1004}
1005
1006/// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
1007/// Refer to C++ 5.2.11 for details. const_cast is typically used in code
1008/// like this:
1009/// const char *str = "literal";
1010/// legacy_function(const_cast\<char*\>(str));
1011void CastOperation::CheckConstCast() {
1012 CheckNoDerefRAII NoderefCheck(*this);
1013
1014 if (ValueKind == VK_PRValue)
1015 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
1016 else if (isPlaceholder())
1017 SrcExpr = Self.CheckPlaceholderExpr(E: SrcExpr.get());
1018 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1019 return;
1020
1021 unsigned msg = diag::err_bad_cxx_cast_generic;
1022 auto TCR = TryConstCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg);
1023 if (TCR != TC_Success && msg != 0) {
1024 Self.Diag(Loc: OpRange.getBegin(), DiagID: msg) << CT_Const
1025 << SrcExpr.get()->getType() << DestType << OpRange;
1026 }
1027 if (!isValidCast(TCR))
1028 SrcExpr = ExprError();
1029}
1030
1031void CastOperation::CheckAddrspaceCast() {
1032 unsigned msg = diag::err_bad_cxx_cast_generic;
1033 auto TCR =
1034 TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg, Kind);
1035 if (TCR != TC_Success && msg != 0) {
1036 Self.Diag(Loc: OpRange.getBegin(), DiagID: msg)
1037 << CT_Addrspace << SrcExpr.get()->getType() << DestType << OpRange;
1038 }
1039 if (!isValidCast(TCR))
1040 SrcExpr = ExprError();
1041}
1042
1043/// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
1044/// or downcast between respective pointers or references.
1045static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
1046 QualType DestType,
1047 CastOperation::OpRangeType OpRange) {
1048 QualType SrcType = SrcExpr->getType();
1049 // When casting from pointer or reference, get pointee type; use original
1050 // type otherwise.
1051 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
1052 const CXXRecordDecl *SrcRD =
1053 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
1054
1055 // Examining subobjects for records is only possible if the complete and
1056 // valid definition is available. Also, template instantiation is not
1057 // allowed here.
1058 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
1059 return;
1060
1061 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
1062
1063 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
1064 return;
1065
1066 enum {
1067 ReinterpretUpcast,
1068 ReinterpretDowncast
1069 } ReinterpretKind;
1070
1071 CXXBasePaths BasePaths;
1072
1073 if (SrcRD->isDerivedFrom(Base: DestRD, Paths&: BasePaths))
1074 ReinterpretKind = ReinterpretUpcast;
1075 else if (DestRD->isDerivedFrom(Base: SrcRD, Paths&: BasePaths))
1076 ReinterpretKind = ReinterpretDowncast;
1077 else
1078 return;
1079
1080 bool VirtualBase = true;
1081 bool NonZeroOffset = false;
1082 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
1083 E = BasePaths.end();
1084 I != E; ++I) {
1085 const CXXBasePath &Path = *I;
1086 CharUnits Offset = CharUnits::Zero();
1087 bool IsVirtual = false;
1088 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
1089 IElem != EElem; ++IElem) {
1090 IsVirtual = IElem->Base->isVirtual();
1091 if (IsVirtual)
1092 break;
1093 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
1094 assert(BaseRD && "Base type should be a valid unqualified class type");
1095 // Don't check if any base has invalid declaration or has no definition
1096 // since it has no layout info.
1097 const CXXRecordDecl *Class = IElem->Class,
1098 *ClassDefinition = Class->getDefinition();
1099 if (Class->isInvalidDecl() || !ClassDefinition ||
1100 !ClassDefinition->isCompleteDefinition())
1101 return;
1102
1103 const ASTRecordLayout &DerivedLayout =
1104 Self.Context.getASTRecordLayout(D: Class);
1105 Offset += DerivedLayout.getBaseClassOffset(Base: BaseRD);
1106 }
1107 if (!IsVirtual) {
1108 // Don't warn if any path is a non-virtually derived base at offset zero.
1109 if (Offset.isZero())
1110 return;
1111 // Offset makes sense only for non-virtual bases.
1112 else
1113 NonZeroOffset = true;
1114 }
1115 VirtualBase = VirtualBase && IsVirtual;
1116 }
1117
1118 (void) NonZeroOffset; // Silence set but not used warning.
1119 assert((VirtualBase || NonZeroOffset) &&
1120 "Should have returned if has non-virtual base with zero offset");
1121
1122 QualType BaseType =
1123 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
1124 QualType DerivedType =
1125 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
1126
1127 SourceLocation BeginLoc = OpRange.getBegin();
1128 Self.Diag(Loc: BeginLoc, DiagID: diag::warn_reinterpret_different_from_static)
1129 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
1130 << OpRange;
1131 Self.Diag(Loc: BeginLoc, DiagID: diag::note_reinterpret_updowncast_use_static)
1132 << int(ReinterpretKind)
1133 << FixItHint::CreateReplacement(RemoveRange: BeginLoc, Code: "static_cast");
1134}
1135
1136static bool argTypeIsABIEquivalent(QualType SrcType, QualType DestType,
1137 ASTContext &Context) {
1138 if (SrcType->isPointerType() && DestType->isPointerType())
1139 return true;
1140
1141 // Allow integral type mismatch if their size are equal.
1142 if ((SrcType->isIntegralType(Ctx: Context) || SrcType->isEnumeralType()) &&
1143 (DestType->isIntegralType(Ctx: Context) || DestType->isEnumeralType()))
1144 if (Context.getTypeSizeInChars(T: SrcType) ==
1145 Context.getTypeSizeInChars(T: DestType))
1146 return true;
1147
1148 return Context.hasSameUnqualifiedType(T1: SrcType, T2: DestType);
1149}
1150
1151static unsigned int checkCastFunctionType(Sema &Self, const ExprResult &SrcExpr,
1152 QualType DestType) {
1153 unsigned int DiagID = 0;
1154 const unsigned int DiagList[] = {diag::warn_cast_function_type_strict,
1155 diag::warn_cast_function_type};
1156 for (auto ID : DiagList) {
1157 if (!Self.Diags.isIgnored(DiagID: ID, Loc: SrcExpr.get()->getExprLoc())) {
1158 DiagID = ID;
1159 break;
1160 }
1161 }
1162 if (!DiagID)
1163 return 0;
1164
1165 QualType SrcType = SrcExpr.get()->getType();
1166 const FunctionType *SrcFTy = nullptr;
1167 const FunctionType *DstFTy = nullptr;
1168 if (((SrcType->isBlockPointerType() || SrcType->isFunctionPointerType()) &&
1169 DestType->isFunctionPointerType()) ||
1170 (SrcType->isMemberFunctionPointerType() &&
1171 DestType->isMemberFunctionPointerType())) {
1172 SrcFTy = SrcType->getPointeeType()->castAs<FunctionType>();
1173 DstFTy = DestType->getPointeeType()->castAs<FunctionType>();
1174 } else if (SrcType->isFunctionType() && DestType->isFunctionReferenceType()) {
1175 SrcFTy = SrcType->castAs<FunctionType>();
1176 DstFTy = DestType.getNonReferenceType()->castAs<FunctionType>();
1177 } else {
1178 return 0;
1179 }
1180 assert(SrcFTy && DstFTy);
1181
1182 if (Self.Context.hasSameType(T1: SrcFTy, T2: DstFTy))
1183 return 0;
1184
1185 // For strict checks, ensure we have an exact match.
1186 if (DiagID == diag::warn_cast_function_type_strict)
1187 return DiagID;
1188
1189 auto IsVoidVoid = [](const FunctionType *T) {
1190 if (!T->getReturnType()->isVoidType())
1191 return false;
1192 if (const auto *PT = T->getAs<FunctionProtoType>())
1193 return !PT->isVariadic() && PT->getNumParams() == 0;
1194 return false;
1195 };
1196
1197 auto IsFarProc = [](const FunctionType *T) {
1198 // The definition of FARPROC depends on the platform in terms of its return
1199 // type, which could be int, or long long, etc. We'll look for a source
1200 // signature for: <integer type> (*)() and call that "close enough" to
1201 // FARPROC to be sufficient to silence the diagnostic. This is similar to
1202 // how we allow casts between function pointers and void * for supporting
1203 // dlsym.
1204 // Note: we could check for __stdcall on the function pointer as well, but
1205 // that seems like splitting hairs.
1206 if (!T->getReturnType()->isIntegerType())
1207 return false;
1208 if (const auto *PT = T->getAs<FunctionProtoType>())
1209 return !PT->isVariadic() && PT->getNumParams() == 0;
1210 return true;
1211 };
1212
1213 // Skip if either function type is void(*)(void)
1214 if (IsVoidVoid(SrcFTy) || IsVoidVoid(DstFTy))
1215 return 0;
1216
1217 // On Windows, GetProcAddress() returns a FARPROC, which is a typedef for a
1218 // function pointer type (with no prototype, in C). We don't want to diagnose
1219 // this case so we don't diagnose idiomatic code on Windows.
1220 if (Self.getASTContext().getTargetInfo().getTriple().isOSWindows() &&
1221 IsFarProc(SrcFTy))
1222 return 0;
1223
1224 // Check return type.
1225 if (!argTypeIsABIEquivalent(SrcType: SrcFTy->getReturnType(), DestType: DstFTy->getReturnType(),
1226 Context&: Self.Context))
1227 return DiagID;
1228
1229 // Check if either has unspecified number of parameters
1230 if (SrcFTy->isFunctionNoProtoType() || DstFTy->isFunctionNoProtoType())
1231 return 0;
1232
1233 // Check parameter types.
1234
1235 const auto *SrcFPTy = cast<FunctionProtoType>(Val: SrcFTy);
1236 const auto *DstFPTy = cast<FunctionProtoType>(Val: DstFTy);
1237
1238 // In a cast involving function types with a variable argument list only the
1239 // types of initial arguments that are provided are considered.
1240 unsigned NumParams = SrcFPTy->getNumParams();
1241 unsigned DstNumParams = DstFPTy->getNumParams();
1242 if (NumParams > DstNumParams) {
1243 if (!DstFPTy->isVariadic())
1244 return DiagID;
1245 NumParams = DstNumParams;
1246 } else if (NumParams < DstNumParams) {
1247 if (!SrcFPTy->isVariadic())
1248 return DiagID;
1249 }
1250
1251 for (unsigned i = 0; i < NumParams; ++i)
1252 if (!argTypeIsABIEquivalent(SrcType: SrcFPTy->getParamType(i),
1253 DestType: DstFPTy->getParamType(i), Context&: Self.Context))
1254 return DiagID;
1255
1256 return 0;
1257}
1258
1259/// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
1260/// valid.
1261/// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
1262/// like this:
1263/// char *bytes = reinterpret_cast\<char*\>(int_ptr);
1264void CastOperation::CheckReinterpretCast() {
1265 if (ValueKind == VK_PRValue && !isPlaceholder(K: BuiltinType::Overload))
1266 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
1267 else
1268 checkNonOverloadPlaceholders();
1269 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1270 return;
1271
1272 unsigned msg = diag::err_bad_cxx_cast_generic;
1273 TryCastResult tcr =
1274 TryReinterpretCast(Self, SrcExpr, DestType,
1275 /*CStyle*/false, OpRange, msg, Kind);
1276 if (tcr != TC_Success && msg != 0) {
1277 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1278 return;
1279 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1280 //FIXME: &f<int>; is overloaded and resolvable
1281 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_reinterpret_cast_overload)
1282 << OverloadExpr::find(E: SrcExpr.get()).Expression->getName()
1283 << DestType << OpRange;
1284 Self.NoteAllOverloadCandidates(E: SrcExpr.get());
1285
1286 } else {
1287 diagnoseBadCast(S&: Self, msg, castType: CT_Reinterpret, opRange: OpRange, src: SrcExpr.get(),
1288 destType: DestType, /*listInitialization=*/false);
1289 }
1290 }
1291
1292 if (isValidCast(TCR: tcr)) {
1293 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1294 checkObjCConversion(CCK: CheckedConversionKind::OtherCast,
1295 /*IsReinterpretCast=*/true);
1296 DiagnoseReinterpretUpDownCast(Self, SrcExpr: SrcExpr.get(), DestType, OpRange);
1297
1298 if (unsigned DiagID = checkCastFunctionType(Self, SrcExpr, DestType))
1299 Self.Diag(Loc: OpRange.getBegin(), DiagID)
1300 << SrcExpr.get()->getType() << DestType << OpRange;
1301 } else {
1302 SrcExpr = ExprError();
1303 }
1304}
1305
1306
1307/// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
1308/// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
1309/// implicit conversions explicit and getting rid of data loss warnings.
1310void CastOperation::CheckStaticCast() {
1311 CheckNoDerefRAII NoderefCheck(*this);
1312
1313 if (isPlaceholder()) {
1314 checkNonOverloadPlaceholders();
1315 if (SrcExpr.isInvalid())
1316 return;
1317 }
1318
1319 // This test is outside everything else because it's the only case where
1320 // a non-lvalue-reference target type does not lead to decay.
1321 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1322 if (DestType->isVoidType()) {
1323 Kind = CK_ToVoid;
1324
1325 if (claimPlaceholder(K: BuiltinType::Overload)) {
1326 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
1327 DoFunctionPointerConversion: false, // Decay Function to ptr
1328 Complain: true, // Complain
1329 OpRangeForComplaining: OpRange, DestTypeForComplaining: DestType, DiagIDForComplaining: diag::err_bad_static_cast_overload);
1330 if (SrcExpr.isInvalid())
1331 return;
1332 }
1333
1334 SrcExpr = Self.IgnoredValueConversions(E: SrcExpr.get());
1335 return;
1336 }
1337
1338 if (ValueKind == VK_PRValue && !DestType->isRecordType() &&
1339 !isPlaceholder(K: BuiltinType::Overload)) {
1340 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
1341 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1342 return;
1343 }
1344
1345 unsigned msg = diag::err_bad_cxx_cast_generic;
1346 TryCastResult tcr =
1347 TryStaticCast(Self, SrcExpr, DestType, CCK: CheckedConversionKind::OtherCast,
1348 OpRange, msg, Kind, BasePath, /*ListInitialization=*/false);
1349 if (tcr != TC_Success && msg != 0) {
1350 if (SrcExpr.isInvalid())
1351 return;
1352 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1353 OverloadExpr* oe = OverloadExpr::find(E: SrcExpr.get()).Expression;
1354 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_static_cast_overload)
1355 << oe->getName() << DestType << OpRange
1356 << oe->getQualifierLoc().getSourceRange();
1357 Self.NoteAllOverloadCandidates(E: SrcExpr.get());
1358 } else {
1359 diagnoseBadCast(S&: Self, msg, castType: CT_Static, opRange: OpRange, src: SrcExpr.get(), destType: DestType,
1360 /*listInitialization=*/false);
1361 }
1362 }
1363
1364 if (isValidCast(TCR: tcr)) {
1365 if (Kind == CK_BitCast)
1366 checkCastAlign();
1367 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1368 checkObjCConversion(CCK: CheckedConversionKind::OtherCast);
1369 } else {
1370 SrcExpr = ExprError();
1371 }
1372}
1373
1374static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) {
1375 auto *SrcPtrType = SrcType->getAs<PointerType>();
1376 if (!SrcPtrType)
1377 return false;
1378 auto *DestPtrType = DestType->getAs<PointerType>();
1379 if (!DestPtrType)
1380 return false;
1381 return SrcPtrType->getPointeeType().getAddressSpace() !=
1382 DestPtrType->getPointeeType().getAddressSpace();
1383}
1384
1385/// TryStaticCast - Check if a static cast can be performed, and do so if
1386/// possible. If @p CStyle, ignore access restrictions on hierarchy casting
1387/// and casting away constness.
1388static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
1389 QualType DestType, CheckedConversionKind CCK,
1390 CastOperation::OpRangeType OpRange,
1391 unsigned &msg, CastKind &Kind,
1392 CXXCastPath &BasePath,
1393 bool ListInitialization) {
1394 // Determine whether we have the semantics of a C-style cast.
1395 bool CStyle = (CCK == CheckedConversionKind::CStyleCast ||
1396 CCK == CheckedConversionKind::FunctionalCast);
1397
1398 // The order the tests is not entirely arbitrary. There is one conversion
1399 // that can be handled in two different ways. Given:
1400 // struct A {};
1401 // struct B : public A {
1402 // B(); B(const A&);
1403 // };
1404 // const A &a = B();
1405 // the cast static_cast<const B&>(a) could be seen as either a static
1406 // reference downcast, or an explicit invocation of the user-defined
1407 // conversion using B's conversion constructor.
1408 // DR 427 specifies that the downcast is to be applied here.
1409
1410 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1411 // Done outside this function.
1412
1413 TryCastResult tcr;
1414
1415 // C++ 5.2.9p5, reference downcast.
1416 // See the function for details.
1417 // DR 427 specifies that this is to be applied before paragraph 2.
1418 tcr = TryStaticReferenceDowncast(Self, SrcExpr: SrcExpr.get(), DestType, CStyle,
1419 OpRange, msg, Kind, BasePath);
1420 if (tcr != TC_NotApplicable)
1421 return tcr;
1422
1423 // C++11 [expr.static.cast]p3:
1424 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
1425 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1426 tcr = TryLValueToRValueCast(Self, SrcExpr: SrcExpr.get(), DestType, CStyle, OpRange,
1427 Kind, BasePath, msg);
1428 if (tcr != TC_NotApplicable)
1429 return tcr;
1430
1431 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
1432 // [...] if the declaration "T t(e);" is well-formed, [...].
1433 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
1434 Kind, ListInitialization);
1435 if (SrcExpr.isInvalid())
1436 return TC_Failed;
1437 if (tcr != TC_NotApplicable)
1438 return tcr;
1439
1440 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
1441 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
1442 // conversions, subject to further restrictions.
1443 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
1444 // of qualification conversions impossible. (In C++20, adding an array bound
1445 // would be the reverse of a qualification conversion, but adding permission
1446 // to add an array bound in a static_cast is a wording oversight.)
1447 // In the CStyle case, the earlier attempt to const_cast should have taken
1448 // care of reverse qualification conversions.
1449
1450 QualType SrcType = Self.Context.getCanonicalType(T: SrcExpr.get()->getType());
1451
1452 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
1453 // converted to an integral type. [...] A value of a scoped enumeration type
1454 // can also be explicitly converted to a floating-point type [...].
1455 if (const EnumType *Enum = dyn_cast<EnumType>(Val&: SrcType)) {
1456 if (Enum->getDecl()->isScoped()) {
1457 if (DestType->isBooleanType()) {
1458 Kind = CK_IntegralToBoolean;
1459 return TC_Success;
1460 } else if (DestType->isIntegralType(Ctx: Self.Context)) {
1461 Kind = CK_IntegralCast;
1462 return TC_Success;
1463 } else if (DestType->isRealFloatingType()) {
1464 Kind = CK_IntegralToFloating;
1465 return TC_Success;
1466 }
1467 }
1468 }
1469
1470 // Reverse integral promotion/conversion. All such conversions are themselves
1471 // again integral promotions or conversions and are thus already handled by
1472 // p2 (TryDirectInitialization above).
1473 // (Note: any data loss warnings should be suppressed.)
1474 // The exception is the reverse of enum->integer, i.e. integer->enum (and
1475 // enum->enum). See also C++ 5.2.9p7.
1476 // The same goes for reverse floating point promotion/conversion and
1477 // floating-integral conversions. Again, only floating->enum is relevant.
1478 if (DestType->isEnumeralType()) {
1479 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: DestType,
1480 DiagID: diag::err_bad_cast_incomplete)) {
1481 SrcExpr = ExprError();
1482 return TC_Failed;
1483 }
1484 if (SrcType->isIntegralOrEnumerationType()) {
1485 // [expr.static.cast]p10 If the enumeration type has a fixed underlying
1486 // type, the value is first converted to that type by integral conversion
1487 const auto *ED = DestType->castAsEnumDecl();
1488 Kind = ED->isFixed() && ED->getIntegerType()->isBooleanType()
1489 ? CK_IntegralToBoolean
1490 : CK_IntegralCast;
1491 return TC_Success;
1492 } else if (SrcType->isRealFloatingType()) {
1493 Kind = CK_FloatingToIntegral;
1494 return TC_Success;
1495 }
1496 }
1497
1498 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1499 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1500 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1501 Kind, BasePath);
1502 if (tcr != TC_NotApplicable)
1503 return tcr;
1504
1505 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1506 // conversion. C++ 5.2.9p9 has additional information.
1507 // DR54's access restrictions apply here also.
1508 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1509 OpRange, msg, Kind, BasePath);
1510 if (tcr != TC_NotApplicable)
1511 return tcr;
1512
1513 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1514 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1515 // just the usual constness stuff.
1516 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1517 QualType SrcPointee = SrcPointer->getPointeeType();
1518 if (SrcPointee->isVoidType()) {
1519 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1520 QualType DestPointee = DestPointer->getPointeeType();
1521 if (DestPointee->isIncompleteOrObjectType()) {
1522 // This is definitely the intended conversion, but it might fail due
1523 // to a qualifier violation. Note that we permit Objective-C lifetime
1524 // and GC qualifier mismatches here.
1525 if (!CStyle) {
1526 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1527 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1528 DestPointeeQuals.removeObjCGCAttr();
1529 DestPointeeQuals.removeObjCLifetime();
1530 SrcPointeeQuals.removeObjCGCAttr();
1531 SrcPointeeQuals.removeObjCLifetime();
1532 if (DestPointeeQuals != SrcPointeeQuals &&
1533 !DestPointeeQuals.compatiblyIncludes(other: SrcPointeeQuals,
1534 Ctx: Self.getASTContext())) {
1535 msg = diag::err_bad_cxx_cast_qualifiers_away;
1536 return TC_Failed;
1537 }
1538 }
1539 Kind = IsAddressSpaceConversion(SrcType, DestType)
1540 ? CK_AddressSpaceConversion
1541 : CK_BitCast;
1542 return TC_Success;
1543 }
1544
1545 // Microsoft permits static_cast from 'pointer-to-void' to
1546 // 'pointer-to-function'.
1547 if (!CStyle && Self.getLangOpts().MSVCCompat &&
1548 DestPointee->isFunctionType()) {
1549 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::ext_ms_cast_fn_obj) << OpRange;
1550 Kind = CK_BitCast;
1551 return TC_Success;
1552 }
1553 }
1554 else if (DestType->isObjCObjectPointerType()) {
1555 // allow both c-style cast and static_cast of objective-c pointers as
1556 // they are pervasive.
1557 Kind = CK_CPointerToObjCPointerCast;
1558 return TC_Success;
1559 }
1560 else if (CStyle && DestType->isBlockPointerType()) {
1561 // allow c-style cast of void * to block pointers.
1562 Kind = CK_AnyPointerToBlockPointerCast;
1563 return TC_Success;
1564 }
1565 }
1566 }
1567 // Allow arbitrary objective-c pointer conversion with static casts.
1568 if (SrcType->isObjCObjectPointerType() &&
1569 DestType->isObjCObjectPointerType()) {
1570 Kind = CK_BitCast;
1571 return TC_Success;
1572 }
1573 // Allow ns-pointer to cf-pointer conversion in either direction
1574 // with static casts.
1575 if (!CStyle &&
1576 Self.ObjC().CheckTollFreeBridgeStaticCast(castType: DestType, castExpr: SrcExpr.get(), Kind))
1577 return TC_Success;
1578
1579 // See if it looks like the user is trying to convert between
1580 // related record types, and select a better diagnostic if so.
1581 if (const auto *SrcPointer = SrcType->getAs<PointerType>())
1582 if (const auto *DestPointer = DestType->getAs<PointerType>())
1583 if (SrcPointer->getPointeeType()->isRecordType() &&
1584 DestPointer->getPointeeType()->isRecordType())
1585 msg = diag::err_bad_cxx_cast_unrelated_class;
1586
1587 if (SrcType->isMatrixType() && DestType->isMatrixType()) {
1588 if (Self.CheckMatrixCast(R: OpRange, DestTy: DestType, SrcTy: SrcType, Kind)) {
1589 SrcExpr = ExprError();
1590 return TC_Failed;
1591 }
1592 return TC_Success;
1593 }
1594
1595 // We tried everything. Everything! Nothing works! :-(
1596 return TC_NotApplicable;
1597}
1598
1599/// Tests whether a conversion according to N2844 is valid.
1600TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
1601 QualType DestType, bool CStyle,
1602 SourceRange OpRange, CastKind &Kind,
1603 CXXCastPath &BasePath, unsigned &msg) {
1604 // C++11 [expr.static.cast]p3:
1605 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1606 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1607 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1608 if (!R)
1609 return TC_NotApplicable;
1610
1611 if (!SrcExpr->isGLValue())
1612 return TC_NotApplicable;
1613
1614 // Because we try the reference downcast before this function, from now on
1615 // this is the only cast possibility, so we issue an error if we fail now.
1616 QualType FromType = SrcExpr->getType();
1617 QualType ToType = R->getPointeeType();
1618 if (CStyle) {
1619 FromType = FromType.getUnqualifiedType();
1620 ToType = ToType.getUnqualifiedType();
1621 }
1622
1623 Sema::ReferenceConversions RefConv;
1624 Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship(
1625 Loc: SrcExpr->getBeginLoc(), T1: ToType, T2: FromType, Conv: &RefConv);
1626 if (RefResult != Sema::Ref_Compatible) {
1627 if (CStyle || RefResult == Sema::Ref_Incompatible)
1628 return TC_NotApplicable;
1629 // Diagnose types which are reference-related but not compatible here since
1630 // we can provide better diagnostics. In these cases forwarding to
1631 // [expr.static.cast]p4 should never result in a well-formed cast.
1632 msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast
1633 : diag::err_bad_rvalue_to_rvalue_cast;
1634 return TC_Failed;
1635 }
1636
1637 if (RefConv & Sema::ReferenceConversions::DerivedToBase) {
1638 Kind = CK_DerivedToBase;
1639 if (Self.CheckDerivedToBaseConversion(Derived: FromType, Base: ToType,
1640 Loc: SrcExpr->getBeginLoc(), Range: OpRange,
1641 BasePath: &BasePath, IgnoreAccess: CStyle)) {
1642 msg = 0;
1643 return TC_Failed;
1644 }
1645 } else
1646 Kind = CK_NoOp;
1647
1648 return TC_Success;
1649}
1650
1651/// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1652TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
1653 QualType DestType, bool CStyle,
1654 CastOperation::OpRangeType OpRange,
1655 unsigned &msg, CastKind &Kind,
1656 CXXCastPath &BasePath) {
1657 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1658 // cast to type "reference to cv2 D", where D is a class derived from B,
1659 // if a valid standard conversion from "pointer to D" to "pointer to B"
1660 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1661 // In addition, DR54 clarifies that the base must be accessible in the
1662 // current context. Although the wording of DR54 only applies to the pointer
1663 // variant of this rule, the intent is clearly for it to apply to the this
1664 // conversion as well.
1665
1666 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1667 if (!DestReference) {
1668 return TC_NotApplicable;
1669 }
1670 bool RValueRef = DestReference->isRValueReferenceType();
1671 if (!RValueRef && !SrcExpr->isLValue()) {
1672 // We know the left side is an lvalue reference, so we can suggest a reason.
1673 msg = diag::err_bad_cxx_cast_rvalue;
1674 return TC_NotApplicable;
1675 }
1676
1677 QualType DestPointee = DestReference->getPointeeType();
1678
1679 // FIXME: If the source is a prvalue, we should issue a warning (because the
1680 // cast always has undefined behavior), and for AST consistency, we should
1681 // materialize a temporary.
1682 return TryStaticDowncast(Self,
1683 SrcType: Self.Context.getCanonicalType(T: SrcExpr->getType()),
1684 DestType: Self.Context.getCanonicalType(T: DestPointee), CStyle,
1685 OpRange, OrigSrcType: SrcExpr->getType(), OrigDestType: DestType, msg, Kind,
1686 BasePath);
1687}
1688
1689/// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1690TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
1691 QualType DestType, bool CStyle,
1692 CastOperation::OpRangeType OpRange,
1693 unsigned &msg, CastKind &Kind,
1694 CXXCastPath &BasePath) {
1695 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1696 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1697 // is a class derived from B, if a valid standard conversion from "pointer
1698 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1699 // class of D.
1700 // In addition, DR54 clarifies that the base must be accessible in the
1701 // current context.
1702
1703 const PointerType *DestPointer = DestType->getAs<PointerType>();
1704 if (!DestPointer) {
1705 return TC_NotApplicable;
1706 }
1707
1708 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1709 if (!SrcPointer) {
1710 msg = diag::err_bad_static_cast_pointer_nonpointer;
1711 return TC_NotApplicable;
1712 }
1713
1714 return TryStaticDowncast(Self,
1715 SrcType: Self.Context.getCanonicalType(T: SrcPointer->getPointeeType()),
1716 DestType: Self.Context.getCanonicalType(T: DestPointer->getPointeeType()),
1717 CStyle, OpRange, OrigSrcType: SrcType, OrigDestType: DestType, msg, Kind,
1718 BasePath);
1719}
1720
1721/// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1722/// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1723/// DestType is possible and allowed.
1724TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
1725 CanQualType DestType, bool CStyle,
1726 CastOperation::OpRangeType OpRange,
1727 QualType OrigSrcType, QualType OrigDestType,
1728 unsigned &msg, CastKind &Kind,
1729 CXXCastPath &BasePath) {
1730 // We can only work with complete types. But don't complain if it doesn't work
1731 if (!Self.isCompleteType(Loc: OpRange.getBegin(), T: SrcType) ||
1732 !Self.isCompleteType(Loc: OpRange.getBegin(), T: DestType))
1733 return TC_NotApplicable;
1734
1735 // Downcast can only happen in class hierarchies, so we need classes.
1736 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1737 return TC_NotApplicable;
1738 }
1739
1740 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1741 /*DetectVirtual=*/true);
1742 if (!Self.IsDerivedFrom(Loc: OpRange.getBegin(), Derived: DestType, Base: SrcType, Paths)) {
1743 return TC_NotApplicable;
1744 }
1745
1746 // Target type does derive from source type. Now we're serious. If an error
1747 // appears now, it's not ignored.
1748 // This may not be entirely in line with the standard. Take for example:
1749 // struct A {};
1750 // struct B : virtual A {
1751 // B(A&);
1752 // };
1753 //
1754 // void f()
1755 // {
1756 // (void)static_cast<const B&>(*((A*)0));
1757 // }
1758 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1759 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1760 // However, both GCC and Comeau reject this example, and accepting it would
1761 // mean more complex code if we're to preserve the nice error message.
1762 // FIXME: Being 100% compliant here would be nice to have.
1763
1764 // Must preserve cv, as always, unless we're in C-style mode.
1765 if (!CStyle &&
1766 !DestType.isAtLeastAsQualifiedAs(Other: SrcType, Ctx: Self.getASTContext())) {
1767 msg = diag::err_bad_cxx_cast_qualifiers_away;
1768 return TC_Failed;
1769 }
1770
1771 if (Paths.isAmbiguous(BaseType: SrcType.getUnqualifiedType())) {
1772 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1773 // that it builds the paths in reverse order.
1774 // To sum up: record all paths to the base and build a nice string from
1775 // them. Use it to spice up the error message.
1776 if (!Paths.isRecordingPaths()) {
1777 Paths.clear();
1778 Paths.setRecordingPaths(true);
1779 Self.IsDerivedFrom(Loc: OpRange.getBegin(), Derived: DestType, Base: SrcType, Paths);
1780 }
1781 std::string PathDisplayStr;
1782 std::set<unsigned> DisplayedPaths;
1783 for (clang::CXXBasePath &Path : Paths) {
1784 if (DisplayedPaths.insert(x: Path.back().SubobjectNumber).second) {
1785 // We haven't displayed a path to this particular base
1786 // class subobject yet.
1787 PathDisplayStr += "\n ";
1788 for (CXXBasePathElement &PE : llvm::reverse(C&: Path))
1789 PathDisplayStr += PE.Base->getType().getAsString() + " -> ";
1790 PathDisplayStr += QualType(DestType).getAsString();
1791 }
1792 }
1793
1794 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_ambiguous_base_to_derived_cast)
1795 << QualType(SrcType).getUnqualifiedType()
1796 << QualType(DestType).getUnqualifiedType()
1797 << PathDisplayStr << OpRange;
1798 msg = 0;
1799 return TC_Failed;
1800 }
1801
1802 if (Paths.getDetectedVirtual() != nullptr) {
1803 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1804 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_static_downcast_via_virtual)
1805 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1806 msg = 0;
1807 return TC_Failed;
1808 }
1809
1810 if (!CStyle) {
1811 switch (Self.CheckBaseClassAccess(AccessLoc: OpRange.getBegin(),
1812 Base: SrcType, Derived: DestType,
1813 Path: Paths.front(),
1814 DiagID: diag::err_downcast_from_inaccessible_base)) {
1815 case Sema::AR_accessible:
1816 case Sema::AR_delayed: // be optimistic
1817 case Sema::AR_dependent: // be optimistic
1818 break;
1819
1820 case Sema::AR_inaccessible:
1821 msg = 0;
1822 return TC_Failed;
1823 }
1824 }
1825
1826 Self.BuildBasePathArray(Paths, BasePath);
1827 Kind = CK_BaseToDerived;
1828 return TC_Success;
1829}
1830
1831/// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1832/// C++ 5.2.9p9 is valid:
1833///
1834/// An rvalue of type "pointer to member of D of type cv1 T" can be
1835/// converted to an rvalue of type "pointer to member of B of type cv2 T",
1836/// where B is a base class of D [...].
1837///
1838TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
1839 QualType SrcType, QualType DestType,
1840 bool CStyle,
1841 CastOperation::OpRangeType OpRange,
1842 unsigned &msg, CastKind &Kind,
1843 CXXCastPath &BasePath) {
1844 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1845 if (!DestMemPtr)
1846 return TC_NotApplicable;
1847
1848 bool WasOverloadedFunction = false;
1849 DeclAccessPair FoundOverload;
1850 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1851 if (FunctionDecl *Fn
1852 = Self.ResolveAddressOfOverloadedFunction(AddressOfExpr: SrcExpr.get(), TargetType: DestType, Complain: false,
1853 Found&: FoundOverload)) {
1854 CXXMethodDecl *M = cast<CXXMethodDecl>(Val: Fn);
1855 SrcType = Self.Context.getMemberPointerType(
1856 T: Fn->getType(), /*Qualifier=*/std::nullopt, Cls: M->getParent());
1857 WasOverloadedFunction = true;
1858 }
1859 }
1860
1861 switch (Self.CheckMemberPointerConversion(
1862 FromType: SrcType, ToPtrType: DestMemPtr, Kind, BasePath, CheckLoc: OpRange.getBegin(), OpRange, IgnoreBaseAccess: CStyle,
1863 Direction: Sema::MemberPointerConversionDirection::Upcast)) {
1864 case Sema::MemberPointerConversionResult::Success:
1865 if (Kind == CK_NullToMemberPointer) {
1866 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1867 return TC_NotApplicable;
1868 }
1869 break;
1870 case Sema::MemberPointerConversionResult::DifferentPointee:
1871 case Sema::MemberPointerConversionResult::NotDerived:
1872 return TC_NotApplicable;
1873 case Sema::MemberPointerConversionResult::Ambiguous:
1874 case Sema::MemberPointerConversionResult::Virtual:
1875 case Sema::MemberPointerConversionResult::Inaccessible:
1876 msg = 0;
1877 return TC_Failed;
1878 }
1879
1880 if (WasOverloadedFunction) {
1881 // Resolve the address of the overloaded function again, this time
1882 // allowing complaints if something goes wrong.
1883 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(AddressOfExpr: SrcExpr.get(),
1884 TargetType: DestType,
1885 Complain: true,
1886 Found&: FoundOverload);
1887 if (!Fn) {
1888 msg = 0;
1889 return TC_Failed;
1890 }
1891
1892 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundDecl: FoundOverload, Fn);
1893 if (!SrcExpr.isUsable()) {
1894 msg = 0;
1895 return TC_Failed;
1896 }
1897 }
1898 return TC_Success;
1899}
1900
1901/// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1902/// is valid:
1903///
1904/// An expression e can be explicitly converted to a type T using a
1905/// @c static_cast if the declaration "T t(e);" is well-formed [...].
1906TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
1907 QualType DestType,
1908 CheckedConversionKind CCK,
1909 CastOperation::OpRangeType OpRange,
1910 unsigned &msg, CastKind &Kind,
1911 bool ListInitialization) {
1912 if (DestType->isRecordType()) {
1913 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: DestType,
1914 DiagID: diag::err_bad_cast_incomplete) ||
1915 Self.RequireNonAbstractType(Loc: OpRange.getBegin(), T: DestType,
1916 DiagID: diag::err_allocation_of_abstract_type)) {
1917 msg = 0;
1918 return TC_Failed;
1919 }
1920 }
1921
1922 InitializedEntity Entity = InitializedEntity::InitializeTemporary(Type: DestType);
1923 InitializationKind InitKind =
1924 (CCK == CheckedConversionKind::CStyleCast)
1925 ? InitializationKind::CreateCStyleCast(StartLoc: OpRange.getBegin(), TypeRange: OpRange,
1926 InitList: ListInitialization)
1927 : (CCK == CheckedConversionKind::FunctionalCast)
1928 ? InitializationKind::CreateFunctionalCast(
1929 StartLoc: OpRange.getBegin(), ParenRange: OpRange.getParenRange(), InitList: ListInitialization)
1930 : InitializationKind::CreateCast(TypeRange: OpRange);
1931 Expr *SrcExprRaw = SrcExpr.get();
1932 // FIXME: Per DR242, we should check for an implicit conversion sequence
1933 // or for a constructor that could be invoked by direct-initialization
1934 // here, not for an initialization sequence.
1935 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1936
1937 // At this point of CheckStaticCast, if the destination is a reference,
1938 // or the expression is an overload expression this has to work.
1939 // There is no other way that works.
1940 // On the other hand, if we're checking a C-style cast, we've still got
1941 // the reinterpret_cast way.
1942 bool CStyle = (CCK == CheckedConversionKind::CStyleCast ||
1943 CCK == CheckedConversionKind::FunctionalCast);
1944 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1945 return TC_NotApplicable;
1946
1947 ExprResult Result = InitSeq.Perform(S&: Self, Entity, Kind: InitKind, Args: SrcExprRaw);
1948 if (Result.isInvalid()) {
1949 msg = 0;
1950 return TC_Failed;
1951 }
1952
1953 if (InitSeq.isConstructorInitialization())
1954 Kind = CK_ConstructorConversion;
1955 else
1956 Kind = CK_NoOp;
1957
1958 SrcExpr = Result;
1959 return TC_Success;
1960}
1961
1962/// TryConstCast - See if a const_cast from source to destination is allowed,
1963/// and perform it if it is.
1964static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1965 QualType DestType, bool CStyle,
1966 unsigned &msg) {
1967 DestType = Self.Context.getCanonicalType(T: DestType);
1968 QualType SrcType = SrcExpr.get()->getType();
1969 bool NeedToMaterializeTemporary = false;
1970
1971 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1972 // C++11 5.2.11p4:
1973 // if a pointer to T1 can be explicitly converted to the type "pointer to
1974 // T2" using a const_cast, then the following conversions can also be
1975 // made:
1976 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1977 // type T2 using the cast const_cast<T2&>;
1978 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1979 // type T2 using the cast const_cast<T2&&>; and
1980 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1981 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1982
1983 if (isa<LValueReferenceType>(Val: DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1984 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1985 // is C-style, static_cast might find a way, so we simply suggest a
1986 // message and tell the parent to keep searching.
1987 msg = diag::err_bad_cxx_cast_rvalue;
1988 return TC_NotApplicable;
1989 }
1990
1991 if (isa<RValueReferenceType>(Val: DestTypeTmp) && SrcExpr.get()->isPRValue()) {
1992 if (!SrcType->isRecordType()) {
1993 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1994 // this is C-style, static_cast can do this.
1995 msg = diag::err_bad_cxx_cast_rvalue;
1996 return TC_NotApplicable;
1997 }
1998
1999 // Materialize the class prvalue so that the const_cast can bind a
2000 // reference to it.
2001 NeedToMaterializeTemporary = true;
2002 }
2003
2004 // It's not completely clear under the standard whether we can
2005 // const_cast bit-field gl-values. Doing so would not be
2006 // intrinsically complicated, but for now, we say no for
2007 // consistency with other compilers and await the word of the
2008 // committee.
2009 if (SrcExpr.get()->refersToBitField()) {
2010 msg = diag::err_bad_cxx_cast_bitfield;
2011 return TC_NotApplicable;
2012 }
2013
2014 DestType = Self.Context.getPointerType(T: DestTypeTmp->getPointeeType());
2015 SrcType = Self.Context.getPointerType(T: SrcType);
2016 }
2017
2018 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
2019 // the rules for const_cast are the same as those used for pointers.
2020
2021 if (!DestType->isPointerType() &&
2022 !DestType->isMemberPointerType() &&
2023 !DestType->isObjCObjectPointerType()) {
2024 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
2025 // was a reference type, we converted it to a pointer above.
2026 // The status of rvalue references isn't entirely clear, but it looks like
2027 // conversion to them is simply invalid.
2028 // C++ 5.2.11p3: For two pointer types [...]
2029 if (!CStyle)
2030 msg = diag::err_bad_const_cast_dest;
2031 return TC_NotApplicable;
2032 }
2033 if (DestType->isFunctionPointerType() ||
2034 DestType->isMemberFunctionPointerType()) {
2035 // Cannot cast direct function pointers.
2036 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
2037 // T is the ultimate pointee of source and target type.
2038 if (!CStyle)
2039 msg = diag::err_bad_const_cast_dest;
2040 return TC_NotApplicable;
2041 }
2042
2043 // C++ [expr.const.cast]p3:
2044 // "For two similar types T1 and T2, [...]"
2045 //
2046 // We only allow a const_cast to change cvr-qualifiers, not other kinds of
2047 // type qualifiers. (Likewise, we ignore other changes when determining
2048 // whether a cast casts away constness.)
2049 if (!Self.Context.hasCvrSimilarType(T1: SrcType, T2: DestType))
2050 return TC_NotApplicable;
2051
2052 if (NeedToMaterializeTemporary)
2053 // This is a const_cast from a class prvalue to an rvalue reference type.
2054 // Materialize a temporary to store the result of the conversion.
2055 SrcExpr = Self.CreateMaterializeTemporaryExpr(T: SrcExpr.get()->getType(),
2056 Temporary: SrcExpr.get(),
2057 /*IsLValueReference*/ BoundToLvalueReference: false);
2058
2059 return TC_Success;
2060}
2061
2062// Checks for undefined behavior in reinterpret_cast.
2063// The cases that is checked for is:
2064// *reinterpret_cast<T*>(&a)
2065// reinterpret_cast<T&>(a)
2066// where accessing 'a' as type 'T' will result in undefined behavior.
2067void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
2068 bool IsDereference,
2069 SourceRange Range) {
2070 unsigned DiagID = IsDereference ?
2071 diag::warn_pointer_indirection_from_incompatible_type :
2072 diag::warn_undefined_reinterpret_cast;
2073
2074 if (Diags.isIgnored(DiagID, Loc: Range.getBegin()))
2075 return;
2076
2077 QualType SrcTy, DestTy;
2078 if (IsDereference) {
2079 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
2080 return;
2081 }
2082 SrcTy = SrcType->getPointeeType();
2083 DestTy = DestType->getPointeeType();
2084 } else {
2085 if (!DestType->getAs<ReferenceType>()) {
2086 return;
2087 }
2088 SrcTy = SrcType;
2089 DestTy = DestType->getPointeeType();
2090 }
2091
2092 // Cast is compatible if the types are the same.
2093 if (Context.hasSameUnqualifiedType(T1: DestTy, T2: SrcTy)) {
2094 return;
2095 }
2096 // or one of the types is a char or void type
2097 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
2098 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
2099 return;
2100 }
2101 // or one of the types is a tag type.
2102 if (isa<TagType>(Val: SrcTy.getCanonicalType()) ||
2103 isa<TagType>(Val: DestTy.getCanonicalType()))
2104 return;
2105
2106 // FIXME: Scoped enums?
2107 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
2108 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
2109 if (Context.getTypeSize(T: DestTy) == Context.getTypeSize(T: SrcTy)) {
2110 return;
2111 }
2112 }
2113
2114 if (SrcTy->isDependentType() || DestTy->isDependentType()) {
2115 return;
2116 }
2117
2118 Diag(Loc: Range.getBegin(), DiagID) << SrcType << DestType << Range;
2119}
2120
2121static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
2122 QualType DestType) {
2123 QualType SrcType = SrcExpr.get()->getType();
2124 if (Self.Context.hasSameType(T1: SrcType, T2: DestType))
2125 return;
2126 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
2127 if (SrcPtrTy->isObjCSelType()) {
2128 QualType DT = DestType;
2129 if (isa<PointerType>(Val: DestType))
2130 DT = DestType->getPointeeType();
2131 if (!DT.getUnqualifiedType()->isVoidType())
2132 Self.Diag(Loc: SrcExpr.get()->getExprLoc(),
2133 DiagID: diag::warn_cast_pointer_from_sel)
2134 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2135 }
2136}
2137
2138/// Diagnose casts that change the calling convention of a pointer to a function
2139/// defined in the current TU.
2140static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr,
2141 QualType DstType,
2142 CastOperation::OpRangeType OpRange) {
2143 // Check if this cast would change the calling convention of a function
2144 // pointer type.
2145 QualType SrcType = SrcExpr.get()->getType();
2146 if (Self.Context.hasSameType(T1: SrcType, T2: DstType) ||
2147 !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType())
2148 return;
2149 const auto *SrcFTy =
2150 SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
2151 const auto *DstFTy =
2152 DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
2153 CallingConv SrcCC = SrcFTy->getCallConv();
2154 CallingConv DstCC = DstFTy->getCallConv();
2155 if (SrcCC == DstCC)
2156 return;
2157
2158 // We have a calling convention cast. Check if the source is a pointer to a
2159 // known, specific function that has already been defined.
2160 Expr *Src = SrcExpr.get()->IgnoreParenImpCasts();
2161 if (auto *UO = dyn_cast<UnaryOperator>(Val: Src))
2162 if (UO->getOpcode() == UO_AddrOf)
2163 Src = UO->getSubExpr()->IgnoreParenImpCasts();
2164 auto *DRE = dyn_cast<DeclRefExpr>(Val: Src);
2165 if (!DRE)
2166 return;
2167 auto *FD = dyn_cast<FunctionDecl>(Val: DRE->getDecl());
2168 if (!FD)
2169 return;
2170
2171 // Only warn if we are casting from the default convention to a non-default
2172 // convention. This can happen when the programmer forgot to apply the calling
2173 // convention to the function declaration and then inserted this cast to
2174 // satisfy the type system.
2175 CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
2176 IsVariadic: FD->isVariadic(), IsCXXMethod: FD->isCXXInstanceMember());
2177 if (DstCC == DefaultCC || SrcCC != DefaultCC)
2178 return;
2179
2180 // Diagnose this cast, as it is probably bad.
2181 StringRef SrcCCName = FunctionType::getNameForCallConv(CC: SrcCC);
2182 StringRef DstCCName = FunctionType::getNameForCallConv(CC: DstCC);
2183 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::warn_cast_calling_conv)
2184 << SrcCCName << DstCCName << OpRange;
2185
2186 // The checks above are cheaper than checking if the diagnostic is enabled.
2187 // However, it's worth checking if the warning is enabled before we construct
2188 // a fixit.
2189 if (Self.Diags.isIgnored(DiagID: diag::warn_cast_calling_conv, Loc: OpRange.getBegin()))
2190 return;
2191
2192 // Try to suggest a fixit to change the calling convention of the function
2193 // whose address was taken. Try to use the latest macro for the convention.
2194 // For example, users probably want to write "WINAPI" instead of "__stdcall"
2195 // to match the Windows header declarations.
2196 SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc();
2197 Preprocessor &PP = Self.getPreprocessor();
2198 SmallVector<TokenValue, 6> AttrTokens;
2199 SmallString<64> CCAttrText;
2200 llvm::raw_svector_ostream OS(CCAttrText);
2201 if (Self.getLangOpts().MicrosoftExt) {
2202 // __stdcall or __vectorcall
2203 OS << "__" << DstCCName;
2204 IdentifierInfo *II = PP.getIdentifierInfo(Name: OS.str());
2205 AttrTokens.push_back(Elt: II->isKeyword(LangOpts: Self.getLangOpts())
2206 ? TokenValue(II->getTokenID())
2207 : TokenValue(II));
2208 } else {
2209 // __attribute__((stdcall)) or __attribute__((vectorcall))
2210 OS << "__attribute__((" << DstCCName << "))";
2211 AttrTokens.push_back(Elt: tok::kw___attribute);
2212 AttrTokens.push_back(Elt: tok::l_paren);
2213 AttrTokens.push_back(Elt: tok::l_paren);
2214 IdentifierInfo *II = PP.getIdentifierInfo(Name: DstCCName);
2215 AttrTokens.push_back(Elt: II->isKeyword(LangOpts: Self.getLangOpts())
2216 ? TokenValue(II->getTokenID())
2217 : TokenValue(II));
2218 AttrTokens.push_back(Elt: tok::r_paren);
2219 AttrTokens.push_back(Elt: tok::r_paren);
2220 }
2221 StringRef AttrSpelling = PP.getLastMacroWithSpelling(Loc: NameLoc, Tokens: AttrTokens);
2222 if (!AttrSpelling.empty())
2223 CCAttrText = AttrSpelling;
2224 OS << ' ';
2225 Self.Diag(Loc: NameLoc, DiagID: diag::note_change_calling_conv_fixit)
2226 << FD << DstCCName << FixItHint::CreateInsertion(InsertionLoc: NameLoc, Code: CCAttrText);
2227}
2228
2229static void checkIntToPointerCast(bool CStyle, const SourceRange &OpRange,
2230 const Expr *SrcExpr, QualType DestType,
2231 Sema &Self) {
2232 QualType SrcType = SrcExpr->getType();
2233
2234 // Not warning on reinterpret_cast, boolean, constant expressions, etc
2235 // are not explicit design choices, but consistent with GCC's behavior.
2236 // Feel free to modify them if you've reason/evidence for an alternative.
2237 if (CStyle && SrcType->isIntegralType(Ctx: Self.Context)
2238 && !SrcType->isBooleanType()
2239 && !SrcType->isEnumeralType()
2240 && !SrcExpr->isIntegerConstantExpr(Ctx: Self.Context)
2241 && Self.Context.getTypeSize(T: DestType) >
2242 Self.Context.getTypeSize(T: SrcType)) {
2243 // Separate between casts to void* and non-void* pointers.
2244 // Some APIs use (abuse) void* for something like a user context,
2245 // and often that value is an integer even if it isn't a pointer itself.
2246 // Having a separate warning flag allows users to control the warning
2247 // for their workflow.
2248 unsigned Diag = DestType->isVoidPointerType() ?
2249 diag::warn_int_to_void_pointer_cast
2250 : diag::warn_int_to_pointer_cast;
2251 Self.Diag(Loc: OpRange.getBegin(), DiagID: Diag) << SrcType << DestType << OpRange;
2252 }
2253}
2254
2255static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
2256 ExprResult &Result) {
2257 // We can only fix an overloaded reinterpret_cast if
2258 // - it is a template with explicit arguments that resolves to an lvalue
2259 // unambiguously, or
2260 // - it is the only function in an overload set that may have its address
2261 // taken.
2262
2263 Expr *E = Result.get();
2264 // TODO: what if this fails because of DiagnoseUseOfDecl or something
2265 // like it?
2266 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2267 SrcExpr&: Result,
2268 DoFunctionPointerConversion: Expr::getValueKindForType(T: DestType) ==
2269 VK_PRValue // Convert Fun to Ptr
2270 ) &&
2271 Result.isUsable())
2272 return true;
2273
2274 // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization
2275 // preserves Result.
2276 Result = E;
2277 if (!Self.resolveAndFixAddressOfSingleOverloadCandidate(
2278 SrcExpr&: Result, /*DoFunctionPointerConversion=*/true))
2279 return false;
2280 return Result.isUsable();
2281}
2282
2283static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
2284 QualType DestType, bool CStyle,
2285 CastOperation::OpRangeType OpRange,
2286 unsigned &msg, CastKind &Kind) {
2287 bool IsLValueCast = false;
2288
2289 DestType = Self.Context.getCanonicalType(T: DestType);
2290 QualType SrcType = SrcExpr.get()->getType();
2291
2292 // Is the source an overloaded name? (i.e. &foo)
2293 // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
2294 if (SrcType == Self.Context.OverloadTy) {
2295 ExprResult FixedExpr = SrcExpr;
2296 if (!fixOverloadedReinterpretCastExpr(Self, DestType, Result&: FixedExpr))
2297 return TC_NotApplicable;
2298
2299 assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
2300 SrcExpr = FixedExpr;
2301 SrcType = SrcExpr.get()->getType();
2302 }
2303
2304 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
2305 if (!SrcExpr.get()->isGLValue()) {
2306 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
2307 // similar comment in const_cast.
2308 msg = diag::err_bad_cxx_cast_rvalue;
2309 return TC_NotApplicable;
2310 }
2311
2312 if (!CStyle) {
2313 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
2314 /*IsDereference=*/false, Range: OpRange);
2315 }
2316
2317 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
2318 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
2319 // built-in & and * operators.
2320
2321 const char *inappropriate = nullptr;
2322 switch (SrcExpr.get()->getObjectKind()) {
2323 case OK_Ordinary:
2324 break;
2325 case OK_BitField:
2326 msg = diag::err_bad_cxx_cast_bitfield;
2327 return TC_NotApplicable;
2328 // FIXME: Use a specific diagnostic for the rest of these cases.
2329 case OK_VectorComponent: inappropriate = "vector element"; break;
2330 case OK_MatrixComponent:
2331 inappropriate = "matrix element";
2332 break;
2333 case OK_ObjCProperty: inappropriate = "property expression"; break;
2334 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
2335 break;
2336 }
2337 if (inappropriate) {
2338 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_reinterpret_cast_reference)
2339 << inappropriate << DestType
2340 << OpRange << SrcExpr.get()->getSourceRange();
2341 msg = 0; SrcExpr = ExprError();
2342 return TC_NotApplicable;
2343 }
2344
2345 // This code does this transformation for the checked types.
2346 DestType = Self.Context.getPointerType(T: DestTypeTmp->getPointeeType());
2347 SrcType = Self.Context.getPointerType(T: SrcType);
2348
2349 IsLValueCast = true;
2350 }
2351
2352 // Canonicalize source for comparison.
2353 SrcType = Self.Context.getCanonicalType(T: SrcType);
2354
2355 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
2356 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
2357 if (DestMemPtr && SrcMemPtr) {
2358 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
2359 // can be explicitly converted to an rvalue of type "pointer to member
2360 // of Y of type T2" if T1 and T2 are both function types or both object
2361 // types.
2362 if (DestMemPtr->isMemberFunctionPointer() !=
2363 SrcMemPtr->isMemberFunctionPointer())
2364 return TC_NotApplicable;
2365
2366 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2367 // We need to determine the inheritance model that the class will use if
2368 // haven't yet.
2369 (void)Self.isCompleteType(Loc: OpRange.getBegin(), T: SrcType);
2370 (void)Self.isCompleteType(Loc: OpRange.getBegin(), T: DestType);
2371 }
2372
2373 // Don't allow casting between member pointers of different sizes.
2374 if (Self.Context.getTypeSize(T: DestMemPtr) !=
2375 Self.Context.getTypeSize(T: SrcMemPtr)) {
2376 msg = diag::err_bad_cxx_cast_member_pointer_size;
2377 return TC_Failed;
2378 }
2379
2380 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
2381 // constness.
2382 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
2383 // we accept it.
2384 if (auto CACK =
2385 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2386 /*CheckObjCLifetime=*/CStyle))
2387 return getCastAwayConstnessCastKind(CACK, DiagID&: msg);
2388
2389 // A valid member pointer cast.
2390 assert(!IsLValueCast);
2391 Kind = CK_ReinterpretMemberPointer;
2392 return TC_Success;
2393 }
2394
2395 // See below for the enumeral issue.
2396 if (SrcType->isNullPtrType() && DestType->isIntegralType(Ctx: Self.Context)) {
2397 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
2398 // type large enough to hold it. A value of std::nullptr_t can be
2399 // converted to an integral type; the conversion has the same meaning
2400 // and validity as a conversion of (void*)0 to the integral type.
2401 if (Self.Context.getTypeSize(T: SrcType) >
2402 Self.Context.getTypeSize(T: DestType)) {
2403 msg = diag::err_bad_reinterpret_cast_small_int;
2404 return TC_Failed;
2405 }
2406 Kind = CK_PointerToIntegral;
2407 return TC_Success;
2408 }
2409
2410 // Allow reinterpret_casts between vectors of the same size and
2411 // between vectors and integers of the same size.
2412 bool destIsVector = DestType->isVectorType();
2413 bool srcIsVector = SrcType->isVectorType();
2414 if (srcIsVector || destIsVector) {
2415 // Allow bitcasting between SVE VLATs and VLSTs, and vice-versa.
2416 if (Self.isValidSveBitcast(srcType: SrcType, destType: DestType)) {
2417 Kind = CK_BitCast;
2418 return TC_Success;
2419 }
2420
2421 // Allow bitcasting between SVE VLATs and VLSTs, and vice-versa.
2422 if (Self.RISCV().isValidRVVBitcast(srcType: SrcType, destType: DestType)) {
2423 Kind = CK_BitCast;
2424 return TC_Success;
2425 }
2426
2427 // The non-vector type, if any, must have integral type. This is
2428 // the same rule that C vector casts use; note, however, that enum
2429 // types are not integral in C++.
2430 if ((!destIsVector && !DestType->isIntegralType(Ctx: Self.Context)) ||
2431 (!srcIsVector && !SrcType->isIntegralType(Ctx: Self.Context)))
2432 return TC_NotApplicable;
2433
2434 // The size we want to consider is eltCount * eltSize.
2435 // That's exactly what the lax-conversion rules will check.
2436 if (Self.areLaxCompatibleVectorTypes(srcType: SrcType, destType: DestType)) {
2437 Kind = CK_BitCast;
2438 return TC_Success;
2439 }
2440
2441 if (Self.LangOpts.OpenCL && !CStyle) {
2442 if (DestType->isExtVectorType() || SrcType->isExtVectorType()) {
2443 // FIXME: Allow for reinterpret cast between 3 and 4 element vectors
2444 if (Self.areVectorTypesSameSize(srcType: SrcType, destType: DestType)) {
2445 Kind = CK_BitCast;
2446 return TC_Success;
2447 }
2448 }
2449 }
2450
2451 // Otherwise, pick a reasonable diagnostic.
2452 if (!destIsVector)
2453 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
2454 else if (!srcIsVector)
2455 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
2456 else
2457 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
2458
2459 return TC_Failed;
2460 }
2461
2462 if (SrcType == DestType) {
2463 // C++ 5.2.10p2 has a note that mentions that, subject to all other
2464 // restrictions, a cast to the same type is allowed so long as it does not
2465 // cast away constness. In C++98, the intent was not entirely clear here,
2466 // since all other paragraphs explicitly forbid casts to the same type.
2467 // C++11 clarifies this case with p2.
2468 //
2469 // The only allowed types are: integral, enumeration, pointer, or
2470 // pointer-to-member types. We also won't restrict Obj-C pointers either.
2471 Kind = CK_NoOp;
2472 TryCastResult Result = TC_NotApplicable;
2473 if (SrcType->isIntegralOrEnumerationType() ||
2474 SrcType->isAnyPointerType() ||
2475 SrcType->isMemberPointerType() ||
2476 SrcType->isBlockPointerType()) {
2477 Result = TC_Success;
2478 }
2479 return Result;
2480 }
2481
2482 bool destIsPtr = DestType->isAnyPointerType() ||
2483 DestType->isBlockPointerType();
2484 bool srcIsPtr = SrcType->isAnyPointerType() ||
2485 SrcType->isBlockPointerType();
2486 if (!destIsPtr && !srcIsPtr) {
2487 // Except for std::nullptr_t->integer and lvalue->reference, which are
2488 // handled above, at least one of the two arguments must be a pointer.
2489 return TC_NotApplicable;
2490 }
2491
2492 if (DestType->isIntegralType(Ctx: Self.Context)) {
2493 assert(srcIsPtr && "One type must be a pointer");
2494 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
2495 // type large enough to hold it; except in Microsoft mode, where the
2496 // integral type size doesn't matter (except we don't allow bool).
2497 if ((Self.Context.getTypeSize(T: SrcType) >
2498 Self.Context.getTypeSize(T: DestType))) {
2499 bool MicrosoftException =
2500 Self.getLangOpts().MicrosoftExt && !DestType->isBooleanType();
2501 if (MicrosoftException) {
2502 unsigned Diag = SrcType->isVoidPointerType()
2503 ? diag::warn_void_pointer_to_int_cast
2504 : diag::warn_pointer_to_int_cast;
2505 Self.Diag(Loc: OpRange.getBegin(), DiagID: Diag) << SrcType << DestType << OpRange;
2506 } else {
2507 msg = diag::err_bad_reinterpret_cast_small_int;
2508 return TC_Failed;
2509 }
2510 }
2511 Kind = CK_PointerToIntegral;
2512 return TC_Success;
2513 }
2514
2515 if (SrcType->isIntegralOrEnumerationType()) {
2516 assert(destIsPtr && "One type must be a pointer");
2517 checkIntToPointerCast(CStyle, OpRange, SrcExpr: SrcExpr.get(), DestType, Self);
2518 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
2519 // converted to a pointer.
2520 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
2521 // necessarily converted to a null pointer value.]
2522 Kind = CK_IntegralToPointer;
2523 return TC_Success;
2524 }
2525
2526 if (!destIsPtr || !srcIsPtr) {
2527 // With the valid non-pointer conversions out of the way, we can be even
2528 // more stringent.
2529 return TC_NotApplicable;
2530 }
2531
2532 // Cannot convert between block pointers and Objective-C object pointers.
2533 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
2534 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
2535 return TC_NotApplicable;
2536
2537 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
2538 // The C-style cast operator can.
2539 TryCastResult SuccessResult = TC_Success;
2540 if (auto CACK =
2541 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2542 /*CheckObjCLifetime=*/CStyle))
2543 SuccessResult = getCastAwayConstnessCastKind(CACK, DiagID&: msg);
2544
2545 if (IsAddressSpaceConversion(SrcType, DestType)) {
2546 Kind = CK_AddressSpaceConversion;
2547 assert(SrcType->isPointerType() && DestType->isPointerType());
2548 if (!CStyle &&
2549 !DestType->getPointeeType().getQualifiers().isAddressSpaceSupersetOf(
2550 other: SrcType->getPointeeType().getQualifiers(), Ctx: Self.getASTContext())) {
2551 SuccessResult = TC_Failed;
2552 }
2553 } else if (IsLValueCast) {
2554 Kind = CK_LValueBitCast;
2555 } else if (DestType->isObjCObjectPointerType()) {
2556 Kind = Self.ObjC().PrepareCastToObjCObjectPointer(E&: SrcExpr);
2557 } else if (DestType->isBlockPointerType()) {
2558 if (!SrcType->isBlockPointerType()) {
2559 Kind = CK_AnyPointerToBlockPointerCast;
2560 } else {
2561 Kind = CK_BitCast;
2562 }
2563 } else {
2564 Kind = CK_BitCast;
2565 }
2566
2567 // Any pointer can be cast to an Objective-C pointer type with a C-style
2568 // cast.
2569 if (CStyle && DestType->isObjCObjectPointerType()) {
2570 return SuccessResult;
2571 }
2572 if (CStyle)
2573 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2574
2575 DiagnoseCallingConvCast(Self, SrcExpr, DstType: DestType, OpRange);
2576
2577 // Not casting away constness, so the only remaining check is for compatible
2578 // pointer categories.
2579
2580 if (SrcType->isFunctionPointerType()) {
2581 if (DestType->isFunctionPointerType()) {
2582 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
2583 // a pointer to a function of a different type.
2584 return SuccessResult;
2585 }
2586
2587 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
2588 // an object type or vice versa is conditionally-supported.
2589 // Compilers support it in C++03 too, though, because it's necessary for
2590 // casting the return value of dlsym() and GetProcAddress().
2591 // FIXME: Conditionally-supported behavior should be configurable in the
2592 // TargetInfo or similar.
2593 Self.Diag(Loc: OpRange.getBegin(),
2594 DiagID: Self.getLangOpts().CPlusPlus11 ?
2595 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2596 << OpRange;
2597 return SuccessResult;
2598 }
2599
2600 if (DestType->isFunctionPointerType()) {
2601 // See above.
2602 Self.Diag(Loc: OpRange.getBegin(),
2603 DiagID: Self.getLangOpts().CPlusPlus11 ?
2604 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2605 << OpRange;
2606 return SuccessResult;
2607 }
2608
2609 // Diagnose address space conversion in nested pointers.
2610 QualType DestPtee = DestType->getPointeeType().isNull()
2611 ? DestType->getPointeeType()
2612 : DestType->getPointeeType()->getPointeeType();
2613 QualType SrcPtee = SrcType->getPointeeType().isNull()
2614 ? SrcType->getPointeeType()
2615 : SrcType->getPointeeType()->getPointeeType();
2616 while (!DestPtee.isNull() && !SrcPtee.isNull()) {
2617 if (DestPtee.getAddressSpace() != SrcPtee.getAddressSpace()) {
2618 Self.Diag(Loc: OpRange.getBegin(),
2619 DiagID: diag::warn_bad_cxx_cast_nested_pointer_addr_space)
2620 << CStyle << SrcType << DestType << SrcExpr.get()->getSourceRange();
2621 break;
2622 }
2623 DestPtee = DestPtee->getPointeeType();
2624 SrcPtee = SrcPtee->getPointeeType();
2625 }
2626
2627 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
2628 // a pointer to an object of different type.
2629 // Void pointers are not specified, but supported by every compiler out there.
2630 // So we finish by allowing everything that remains - it's got to be two
2631 // object pointers.
2632 return SuccessResult;
2633}
2634
2635static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
2636 QualType DestType, bool CStyle,
2637 unsigned &msg, CastKind &Kind) {
2638 if (!Self.getLangOpts().OpenCL && !Self.getLangOpts().SYCLIsDevice)
2639 // FIXME: As compiler doesn't have any information about overlapping addr
2640 // spaces at the moment we have to be permissive here.
2641 return TC_NotApplicable;
2642 // Even though the logic below is general enough and can be applied to
2643 // non-OpenCL mode too, we fast-path above because no other languages
2644 // define overlapping address spaces currently.
2645 auto SrcType = SrcExpr.get()->getType();
2646 // FIXME: Should this be generalized to references? The reference parameter
2647 // however becomes a reference pointee type here and therefore rejected.
2648 // Perhaps this is the right behavior though according to C++.
2649 auto SrcPtrType = SrcType->getAs<PointerType>();
2650 if (!SrcPtrType)
2651 return TC_NotApplicable;
2652 auto DestPtrType = DestType->getAs<PointerType>();
2653 if (!DestPtrType)
2654 return TC_NotApplicable;
2655 auto SrcPointeeType = SrcPtrType->getPointeeType();
2656 auto DestPointeeType = DestPtrType->getPointeeType();
2657 if (!DestPointeeType.isAddressSpaceOverlapping(T: SrcPointeeType,
2658 Ctx: Self.getASTContext())) {
2659 msg = diag::err_bad_cxx_cast_addr_space_mismatch;
2660 return TC_Failed;
2661 }
2662 auto SrcPointeeTypeWithoutAS =
2663 Self.Context.removeAddrSpaceQualType(T: SrcPointeeType.getCanonicalType());
2664 auto DestPointeeTypeWithoutAS =
2665 Self.Context.removeAddrSpaceQualType(T: DestPointeeType.getCanonicalType());
2666 if (Self.Context.hasSameType(T1: SrcPointeeTypeWithoutAS,
2667 T2: DestPointeeTypeWithoutAS)) {
2668 Kind = SrcPointeeType.getAddressSpace() == DestPointeeType.getAddressSpace()
2669 ? CK_NoOp
2670 : CK_AddressSpaceConversion;
2671 return TC_Success;
2672 } else {
2673 return TC_NotApplicable;
2674 }
2675}
2676
2677void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) {
2678 // In OpenCL only conversions between pointers to objects in overlapping
2679 // addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps
2680 // with any named one, except for constant.
2681
2682 // Converting the top level pointee addrspace is permitted for compatible
2683 // addrspaces (such as 'generic int *' to 'local int *' or vice versa), but
2684 // if any of the nested pointee addrspaces differ, we emit a warning
2685 // regardless of addrspace compatibility. This makes
2686 // local int ** p;
2687 // return (generic int **) p;
2688 // warn even though local -> generic is permitted.
2689 if (Self.getLangOpts().OpenCL) {
2690 const Type *DestPtr, *SrcPtr;
2691 bool Nested = false;
2692 unsigned DiagID = diag::err_typecheck_incompatible_address_space;
2693 DestPtr = Self.getASTContext().getCanonicalType(T: DestType.getTypePtr()),
2694 SrcPtr = Self.getASTContext().getCanonicalType(T: SrcType.getTypePtr());
2695
2696 while (isa<PointerType>(Val: DestPtr) && isa<PointerType>(Val: SrcPtr)) {
2697 const PointerType *DestPPtr = cast<PointerType>(Val: DestPtr);
2698 const PointerType *SrcPPtr = cast<PointerType>(Val: SrcPtr);
2699 QualType DestPPointee = DestPPtr->getPointeeType();
2700 QualType SrcPPointee = SrcPPtr->getPointeeType();
2701 if (Nested
2702 ? DestPPointee.getAddressSpace() != SrcPPointee.getAddressSpace()
2703 : !DestPPointee.isAddressSpaceOverlapping(T: SrcPPointee,
2704 Ctx: Self.getASTContext())) {
2705 Self.Diag(Loc: OpRange.getBegin(), DiagID)
2706 << SrcType << DestType << AssignmentAction::Casting
2707 << SrcExpr.get()->getSourceRange();
2708 if (!Nested)
2709 SrcExpr = ExprError();
2710 return;
2711 }
2712
2713 DestPtr = DestPPtr->getPointeeType().getTypePtr();
2714 SrcPtr = SrcPPtr->getPointeeType().getTypePtr();
2715 Nested = true;
2716 DiagID = diag::ext_nested_pointer_qualifier_mismatch;
2717 }
2718 }
2719}
2720
2721bool Sema::ShouldSplatAltivecScalarInCast(const VectorType *VecTy) {
2722 bool SrcCompatXL = this->getLangOpts().getAltivecSrcCompat() ==
2723 LangOptions::AltivecSrcCompatKind::XL;
2724 VectorKind VKind = VecTy->getVectorKind();
2725
2726 if ((VKind == VectorKind::AltiVecVector) ||
2727 (SrcCompatXL && ((VKind == VectorKind::AltiVecBool) ||
2728 (VKind == VectorKind::AltiVecPixel)))) {
2729 return true;
2730 }
2731 return false;
2732}
2733
2734bool Sema::CheckAltivecInitFromScalar(SourceRange R, QualType VecTy,
2735 QualType SrcTy) {
2736 bool SrcCompatGCC = this->getLangOpts().getAltivecSrcCompat() ==
2737 LangOptions::AltivecSrcCompatKind::GCC;
2738 if (this->getLangOpts().AltiVec && SrcCompatGCC) {
2739 this->Diag(Loc: R.getBegin(),
2740 DiagID: diag::err_invalid_conversion_between_vector_and_integer)
2741 << VecTy << SrcTy << R;
2742 return true;
2743 }
2744 return false;
2745}
2746
2747void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2748 bool ListInitialization) {
2749 assert(Self.getLangOpts().CPlusPlus);
2750
2751 // Handle placeholders.
2752 if (isPlaceholder()) {
2753 // C-style casts can resolve __unknown_any types.
2754 if (claimPlaceholder(K: BuiltinType::UnknownAny)) {
2755 SrcExpr = Self.checkUnknownAnyCast(TypeRange: DestRange, CastType: DestType,
2756 CastExpr: SrcExpr.get(), CastKind&: Kind,
2757 VK&: ValueKind, Path&: BasePath);
2758 return;
2759 }
2760
2761 checkNonOverloadPlaceholders();
2762 if (SrcExpr.isInvalid())
2763 return;
2764 }
2765
2766 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2767 // This test is outside everything else because it's the only case where
2768 // a non-lvalue-reference target type does not lead to decay.
2769 if (DestType->isVoidType()) {
2770 Kind = CK_ToVoid;
2771
2772 if (claimPlaceholder(K: BuiltinType::Overload)) {
2773 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2774 SrcExpr, /* Decay Function to ptr */ DoFunctionPointerConversion: false,
2775 /* Complain */ true, OpRangeForComplaining: DestRange, DestTypeForComplaining: DestType,
2776 DiagIDForComplaining: diag::err_bad_cstyle_cast_overload);
2777 if (SrcExpr.isInvalid())
2778 return;
2779 }
2780
2781 SrcExpr = Self.IgnoredValueConversions(E: SrcExpr.get());
2782 return;
2783 }
2784
2785 // If the type is dependent, we won't do any other semantic analysis now.
2786 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2787 SrcExpr.get()->isValueDependent()) {
2788 assert(Kind == CK_Dependent);
2789 return;
2790 }
2791
2792 CheckedConversionKind CCK = FunctionalStyle
2793 ? CheckedConversionKind::FunctionalCast
2794 : CheckedConversionKind::CStyleCast;
2795 if (Self.getLangOpts().HLSL) {
2796 if (CheckHLSLCStyleCast(CCK))
2797 return;
2798 }
2799
2800 if (ValueKind == VK_PRValue && !DestType->isRecordType() &&
2801 !isPlaceholder(K: BuiltinType::Overload)) {
2802 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
2803 if (SrcExpr.isInvalid())
2804 return;
2805 }
2806
2807 // AltiVec vector initialization with a single literal.
2808 if (const VectorType *vecTy = DestType->getAs<VectorType>()) {
2809 if (Self.CheckAltivecInitFromScalar(R: OpRange, VecTy: DestType,
2810 SrcTy: SrcExpr.get()->getType())) {
2811 SrcExpr = ExprError();
2812 return;
2813 }
2814 if (Self.ShouldSplatAltivecScalarInCast(VecTy: vecTy) &&
2815 (SrcExpr.get()->getType()->isIntegerType() ||
2816 SrcExpr.get()->getType()->isFloatingType())) {
2817 Kind = CK_VectorSplat;
2818 SrcExpr = Self.prepareVectorSplat(VectorTy: DestType, SplattedExpr: SrcExpr.get());
2819 return;
2820 }
2821 }
2822
2823 // WebAssembly tables cannot be cast.
2824 QualType SrcType = SrcExpr.get()->getType();
2825 if (SrcType->isWebAssemblyTableType()) {
2826 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_wasm_cast_table)
2827 << 1 << SrcExpr.get()->getSourceRange();
2828 SrcExpr = ExprError();
2829 return;
2830 }
2831
2832 // C++ [expr.cast]p5: The conversions performed by
2833 // - a const_cast,
2834 // - a static_cast,
2835 // - a static_cast followed by a const_cast,
2836 // - a reinterpret_cast, or
2837 // - a reinterpret_cast followed by a const_cast,
2838 // can be performed using the cast notation of explicit type conversion.
2839 // [...] If a conversion can be interpreted in more than one of the ways
2840 // listed above, the interpretation that appears first in the list is used,
2841 // even if a cast resulting from that interpretation is ill-formed.
2842 // In plain language, this means trying a const_cast ...
2843 // Note that for address space we check compatibility after const_cast.
2844 unsigned msg = diag::err_bad_cxx_cast_generic;
2845 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2846 /*CStyle*/ true, msg);
2847 if (SrcExpr.isInvalid())
2848 return;
2849 if (isValidCast(TCR: tcr))
2850 Kind = CK_NoOp;
2851
2852 if (tcr == TC_NotApplicable) {
2853 tcr = TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ true, msg,
2854 Kind);
2855 if (SrcExpr.isInvalid())
2856 return;
2857
2858 if (tcr == TC_NotApplicable) {
2859 // ... or if that is not possible, a static_cast, ignoring const and
2860 // addr space, ...
2861 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, msg, Kind,
2862 BasePath, ListInitialization);
2863 if (SrcExpr.isInvalid())
2864 return;
2865
2866 if (tcr == TC_NotApplicable) {
2867 // ... and finally a reinterpret_cast, ignoring const and addr space.
2868 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/ true,
2869 OpRange, msg, Kind);
2870 if (SrcExpr.isInvalid())
2871 return;
2872 }
2873 }
2874 }
2875
2876 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
2877 isValidCast(TCR: tcr))
2878 checkObjCConversion(CCK);
2879
2880 if (tcr != TC_Success && msg != 0) {
2881 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2882 DeclAccessPair Found;
2883 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(AddressOfExpr: SrcExpr.get(),
2884 TargetType: DestType,
2885 /*Complain*/ true,
2886 Found);
2887 if (Fn) {
2888 // If DestType is a function type (not to be confused with the function
2889 // pointer type), it will be possible to resolve the function address,
2890 // but the type cast should be considered as failure.
2891 OverloadExpr *OE = OverloadExpr::find(E: SrcExpr.get()).Expression;
2892 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_cstyle_cast_overload)
2893 << OE->getName() << DestType << OpRange
2894 << OE->getQualifierLoc().getSourceRange();
2895 Self.NoteAllOverloadCandidates(E: SrcExpr.get());
2896 }
2897 } else {
2898 diagnoseBadCast(S&: Self, msg, castType: (FunctionalStyle ? CT_Functional : CT_CStyle),
2899 opRange: OpRange, src: SrcExpr.get(), destType: DestType, listInitialization: ListInitialization);
2900 }
2901 }
2902
2903 if (isValidCast(TCR: tcr)) {
2904 if (Kind == CK_BitCast)
2905 checkCastAlign();
2906
2907 if (unsigned DiagID = checkCastFunctionType(Self, SrcExpr, DestType))
2908 Self.Diag(Loc: OpRange.getBegin(), DiagID)
2909 << SrcExpr.get()->getType() << DestType << OpRange;
2910
2911 } else {
2912 SrcExpr = ExprError();
2913 }
2914}
2915
2916// CheckHLSLCStyleCast - Returns `true` ihe cast is handled or errored as an
2917// HLSL-specific cast. Returns false if the cast should be checked as a CXX
2918// C-Style cast.
2919bool CastOperation::CheckHLSLCStyleCast(CheckedConversionKind CCK) {
2920 assert(Self.getLangOpts().HLSL && "Must be HLSL!");
2921 QualType SrcTy = SrcExpr.get()->getType();
2922 // HLSL has several unique forms of C-style casts which support aggregate to
2923 // aggregate casting.
2924 // This case should not trigger on regular vector cast, vector truncation
2925 if (Self.HLSL().CanPerformElementwiseCast(Src: SrcExpr.get(), DestType)) {
2926 if (SrcTy->isConstantArrayType())
2927 SrcExpr = Self.ImpCastExprToType(
2928 E: SrcExpr.get(), Type: Self.Context.getArrayParameterType(Ty: SrcTy),
2929 CK: CK_HLSLArrayRValue, VK: VK_PRValue, BasePath: nullptr, CCK);
2930 else
2931 SrcExpr = Self.DefaultLvalueConversion(E: SrcExpr.get());
2932 Kind = CK_HLSLElementwiseCast;
2933 return true;
2934 }
2935
2936 // This case should not trigger on regular vector splat
2937 // If the relative order of this and the HLSLElementWise cast checks
2938 // are changed, it might change which cast handles what in a few cases
2939 if (Self.HLSL().CanPerformAggregateSplatCast(Src: SrcExpr.get(), DestType)) {
2940 SrcExpr = Self.DefaultLvalueConversion(E: SrcExpr.get());
2941 const VectorType *VT = SrcTy->getAs<VectorType>();
2942 // change splat from vec1 case to splat from scalar
2943 if (VT && VT->getNumElements() == 1)
2944 SrcExpr = Self.ImpCastExprToType(
2945 E: SrcExpr.get(), Type: VT->getElementType(), CK: CK_HLSLVectorTruncation,
2946 VK: SrcExpr.get()->getValueKind(), BasePath: nullptr, CCK);
2947 // Inserting a scalar cast here allows for a simplified codegen in
2948 // the case the destTy is a vector
2949 if (const VectorType *DVT = DestType->getAs<VectorType>())
2950 SrcExpr = Self.ImpCastExprToType(
2951 E: SrcExpr.get(), Type: DVT->getElementType(),
2952 CK: Self.PrepareScalarCast(src&: SrcExpr, destType: DVT->getElementType()),
2953 VK: SrcExpr.get()->getValueKind(), BasePath: nullptr, CCK);
2954 Kind = CK_HLSLAggregateSplatCast;
2955 return true;
2956 }
2957
2958 // If the destination is an array, we've exhausted the valid HLSL casts, so we
2959 // should emit a dignostic and stop processing.
2960 if (DestType->isArrayType()) {
2961 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bad_cxx_cast_generic)
2962 << 4 << SrcTy << DestType;
2963 SrcExpr = ExprError();
2964 return true;
2965 }
2966 return false;
2967}
2968
2969/// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2970/// non-matching type. Such as enum function call to int, int call to
2971/// pointer; etc. Cast to 'void' is an exception.
2972static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2973 QualType DestType) {
2974 if (Self.Diags.isIgnored(DiagID: diag::warn_bad_function_cast,
2975 Loc: SrcExpr.get()->getExprLoc()))
2976 return;
2977
2978 if (!isa<CallExpr>(Val: SrcExpr.get()))
2979 return;
2980
2981 QualType SrcType = SrcExpr.get()->getType();
2982 if (DestType.getUnqualifiedType()->isVoidType())
2983 return;
2984 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2985 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2986 return;
2987 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2988 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2989 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2990 return;
2991 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2992 return;
2993 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2994 return;
2995 if (SrcType->isComplexType() && DestType->isComplexType())
2996 return;
2997 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2998 return;
2999 if (SrcType->isFixedPointType() && DestType->isFixedPointType())
3000 return;
3001
3002 Self.Diag(Loc: SrcExpr.get()->getExprLoc(),
3003 DiagID: diag::warn_bad_function_cast)
3004 << SrcType << DestType << SrcExpr.get()->getSourceRange();
3005}
3006
3007/// Check the semantics of a C-style cast operation, in C.
3008void CastOperation::CheckCStyleCast() {
3009 assert(!Self.getLangOpts().CPlusPlus);
3010
3011 // C-style casts can resolve __unknown_any types.
3012 if (claimPlaceholder(K: BuiltinType::UnknownAny)) {
3013 SrcExpr = Self.checkUnknownAnyCast(TypeRange: DestRange, CastType: DestType,
3014 CastExpr: SrcExpr.get(), CastKind&: Kind,
3015 VK&: ValueKind, Path&: BasePath);
3016 return;
3017 }
3018
3019 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
3020 // type needs to be scalar.
3021 if (DestType->isVoidType()) {
3022 // We don't necessarily do lvalue-to-rvalue conversions on this.
3023 SrcExpr = Self.IgnoredValueConversions(E: SrcExpr.get());
3024 if (SrcExpr.isInvalid())
3025 return;
3026
3027 // Cast to void allows any expr type.
3028 Kind = CK_ToVoid;
3029 return;
3030 }
3031
3032 // If the type is dependent, we won't do any other semantic analysis now.
3033 if (Self.getASTContext().isDependenceAllowed() &&
3034 (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
3035 SrcExpr.get()->isValueDependent())) {
3036 assert((DestType->containsErrors() || SrcExpr.get()->containsErrors() ||
3037 SrcExpr.get()->containsErrors()) &&
3038 "should only occur in error-recovery path.");
3039 assert(Kind == CK_Dependent);
3040 return;
3041 }
3042
3043 // Overloads are allowed with C extensions, so we need to support them.
3044 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
3045 DeclAccessPair DAP;
3046 if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction(
3047 AddressOfExpr: SrcExpr.get(), TargetType: DestType, /*Complain=*/true, Found&: DAP))
3048 SrcExpr = Self.FixOverloadedFunctionReference(E: SrcExpr.get(), FoundDecl: DAP, Fn: FD);
3049 else
3050 return;
3051 assert(SrcExpr.isUsable());
3052 }
3053 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(E: SrcExpr.get());
3054 if (SrcExpr.isInvalid())
3055 return;
3056 QualType SrcType = SrcExpr.get()->getType();
3057
3058 if (SrcType->isWebAssemblyTableType()) {
3059 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_wasm_cast_table)
3060 << 1 << SrcExpr.get()->getSourceRange();
3061 SrcExpr = ExprError();
3062 return;
3063 }
3064
3065 assert(!SrcType->isPlaceholderType());
3066
3067 checkAddressSpaceCast(SrcType, DestType);
3068 if (SrcExpr.isInvalid())
3069 return;
3070
3071 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: DestType,
3072 DiagID: diag::err_typecheck_cast_to_incomplete)) {
3073 SrcExpr = ExprError();
3074 return;
3075 }
3076
3077 // Allow casting a sizeless built-in type to itself.
3078 if (DestType->isSizelessBuiltinType() &&
3079 Self.Context.hasSameUnqualifiedType(T1: DestType, T2: SrcType)) {
3080 Kind = CK_NoOp;
3081 return;
3082 }
3083
3084 // Allow bitcasting between compatible SVE vector types.
3085 if ((SrcType->isVectorType() || DestType->isVectorType()) &&
3086 Self.isValidSveBitcast(srcType: SrcType, destType: DestType)) {
3087 Kind = CK_BitCast;
3088 return;
3089 }
3090
3091 // Allow bitcasting between compatible RVV vector types.
3092 if ((SrcType->isVectorType() || DestType->isVectorType()) &&
3093 Self.RISCV().isValidRVVBitcast(srcType: SrcType, destType: DestType)) {
3094 Kind = CK_BitCast;
3095 return;
3096 }
3097
3098 if (!DestType->isScalarType() && !DestType->isVectorType() &&
3099 !DestType->isMatrixType()) {
3100 if (const RecordType *DestRecordTy =
3101 DestType->getAsCanonical<RecordType>()) {
3102 if (Self.Context.hasSameUnqualifiedType(T1: DestType, T2: SrcType)) {
3103 // GCC struct/union extension: allow cast to self.
3104 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::ext_typecheck_cast_nonscalar)
3105 << DestType << SrcExpr.get()->getSourceRange();
3106 Kind = CK_NoOp;
3107 return;
3108 }
3109
3110 // GCC's cast to union extension.
3111 if (RecordDecl *RD = DestRecordTy->getDecl(); RD->isUnion()) {
3112 if (CastExpr::getTargetFieldForToUnionCast(RD: RD->getDefinitionOrSelf(),
3113 opType: SrcType)) {
3114 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::ext_typecheck_cast_to_union)
3115 << SrcExpr.get()->getSourceRange();
3116 Kind = CK_ToUnion;
3117 return;
3118 }
3119 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_typecheck_cast_to_union_no_type)
3120 << SrcType << SrcExpr.get()->getSourceRange();
3121 SrcExpr = ExprError();
3122 return;
3123 }
3124 }
3125
3126 // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type.
3127 if (Self.getLangOpts().OpenCL && DestType->isEventT()) {
3128 Expr::EvalResult Result;
3129 if (SrcExpr.get()->EvaluateAsInt(Result, Ctx: Self.Context)) {
3130 llvm::APSInt CastInt = Result.Val.getInt();
3131 if (0 == CastInt) {
3132 Kind = CK_ZeroToOCLOpaqueType;
3133 return;
3134 }
3135 Self.Diag(Loc: OpRange.getBegin(),
3136 DiagID: diag::err_opencl_cast_non_zero_to_event_t)
3137 << toString(I: CastInt, Radix: 10) << SrcExpr.get()->getSourceRange();
3138 SrcExpr = ExprError();
3139 return;
3140 }
3141 }
3142
3143 // Reject any other conversions to non-scalar types.
3144 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_typecheck_cond_expect_scalar)
3145 << DestType << SrcExpr.get()->getSourceRange();
3146 SrcExpr = ExprError();
3147 return;
3148 }
3149
3150 // The type we're casting to is known to be a scalar, a vector, or a matrix.
3151
3152 // Require the operand to be a scalar, a vector, or a matrix.
3153 if (!SrcType->isScalarType() && !SrcType->isVectorType() &&
3154 !SrcType->isMatrixType()) {
3155 Self.Diag(Loc: SrcExpr.get()->getExprLoc(),
3156 DiagID: diag::err_typecheck_expect_scalar_operand)
3157 << SrcType << SrcExpr.get()->getSourceRange();
3158 SrcExpr = ExprError();
3159 return;
3160 }
3161
3162 // C23 6.5.5p4:
3163 // ... The type nullptr_t shall not be converted to any type other than
3164 // void, bool or a pointer type.If the target type is nullptr_t, the cast
3165 // expression shall be a null pointer constant or have type nullptr_t.
3166 if (SrcType->isNullPtrType()) {
3167 // FIXME: 6.3.2.4p2 says that nullptr_t can be converted to itself, but
3168 // 6.5.4p4 is a constraint check and nullptr_t is not void, bool, or a
3169 // pointer type. We're not going to diagnose that as a constraint violation.
3170 if (!DestType->isVoidType() && !DestType->isBooleanType() &&
3171 !DestType->isPointerType() && !DestType->isNullPtrType()) {
3172 Self.Diag(Loc: SrcExpr.get()->getExprLoc(), DiagID: diag::err_nullptr_cast)
3173 << /*nullptr to type*/ 0 << DestType;
3174 SrcExpr = ExprError();
3175 return;
3176 }
3177 if (DestType->isBooleanType()) {
3178 SrcExpr = ImplicitCastExpr::Create(
3179 Context: Self.Context, T: DestType, Kind: CK_PointerToBoolean, Operand: SrcExpr.get(), BasePath: nullptr,
3180 Cat: VK_PRValue, FPO: Self.CurFPFeatureOverrides());
3181
3182 } else if (!DestType->isNullPtrType()) {
3183 // Implicitly cast from the null pointer type to the type of the
3184 // destination.
3185 CastKind CK = DestType->isPointerType() ? CK_NullToPointer : CK_BitCast;
3186 SrcExpr = ImplicitCastExpr::Create(Context: Self.Context, T: DestType, Kind: CK,
3187 Operand: SrcExpr.get(), BasePath: nullptr, Cat: VK_PRValue,
3188 FPO: Self.CurFPFeatureOverrides());
3189 }
3190 }
3191
3192 if (DestType->isNullPtrType() && !SrcType->isNullPtrType()) {
3193 if (!SrcExpr.get()->isNullPointerConstant(Ctx&: Self.Context,
3194 NPC: Expr::NPC_NeverValueDependent)) {
3195 Self.Diag(Loc: SrcExpr.get()->getExprLoc(), DiagID: diag::err_nullptr_cast)
3196 << /*type to nullptr*/ 1 << SrcType;
3197 SrcExpr = ExprError();
3198 return;
3199 }
3200 // Need to convert the source from whatever its type is to a null pointer
3201 // type first.
3202 SrcExpr = ImplicitCastExpr::Create(Context: Self.Context, T: DestType, Kind: CK_NullToPointer,
3203 Operand: SrcExpr.get(), BasePath: nullptr, Cat: VK_PRValue,
3204 FPO: Self.CurFPFeatureOverrides());
3205 }
3206
3207 if (DestType->isExtVectorType()) {
3208 SrcExpr = Self.CheckExtVectorCast(R: OpRange, DestTy: DestType, CastExpr: SrcExpr.get(), Kind);
3209 return;
3210 }
3211
3212 if (DestType->getAs<MatrixType>() || SrcType->getAs<MatrixType>()) {
3213 if (Self.CheckMatrixCast(R: OpRange, DestTy: DestType, SrcTy: SrcType, Kind))
3214 SrcExpr = ExprError();
3215 return;
3216 }
3217
3218 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
3219 if (Self.CheckAltivecInitFromScalar(R: OpRange, VecTy: DestType, SrcTy: SrcType)) {
3220 SrcExpr = ExprError();
3221 return;
3222 }
3223 if (Self.ShouldSplatAltivecScalarInCast(VecTy: DestVecTy) &&
3224 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
3225 Kind = CK_VectorSplat;
3226 SrcExpr = Self.prepareVectorSplat(VectorTy: DestType, SplattedExpr: SrcExpr.get());
3227 } else if (Self.CheckVectorCast(R: OpRange, VectorTy: DestType, Ty: SrcType, Kind)) {
3228 SrcExpr = ExprError();
3229 }
3230 return;
3231 }
3232
3233 if (SrcType->isVectorType()) {
3234 if (Self.CheckVectorCast(R: OpRange, VectorTy: SrcType, Ty: DestType, Kind))
3235 SrcExpr = ExprError();
3236 return;
3237 }
3238
3239 // The source and target types are both scalars, i.e.
3240 // - arithmetic types (fundamental, enum, and complex)
3241 // - all kinds of pointers
3242 // Note that member pointers were filtered out with C++, above.
3243
3244 if (isa<ObjCSelectorExpr>(Val: SrcExpr.get())) {
3245 Self.Diag(Loc: SrcExpr.get()->getExprLoc(), DiagID: diag::err_cast_selector_expr);
3246 SrcExpr = ExprError();
3247 return;
3248 }
3249
3250 // If either type is a pointer, the other type has to be either an
3251 // integer or a pointer.
3252 if (!DestType->isArithmeticType()) {
3253 if (!SrcType->isIntegralType(Ctx: Self.Context) && SrcType->isArithmeticType()) {
3254 Self.Diag(Loc: SrcExpr.get()->getExprLoc(),
3255 DiagID: diag::err_cast_pointer_from_non_pointer_int)
3256 << SrcType << SrcExpr.get()->getSourceRange();
3257 SrcExpr = ExprError();
3258 return;
3259 }
3260 checkIntToPointerCast(/* CStyle */ true, OpRange, SrcExpr: SrcExpr.get(), DestType,
3261 Self);
3262 } else if (!SrcType->isArithmeticType()) {
3263 if (!DestType->isIntegralType(Ctx: Self.Context) &&
3264 DestType->isArithmeticType()) {
3265 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(),
3266 DiagID: diag::err_cast_pointer_to_non_pointer_int)
3267 << DestType << SrcExpr.get()->getSourceRange();
3268 SrcExpr = ExprError();
3269 return;
3270 }
3271
3272 if ((Self.Context.getTypeSize(T: SrcType) >
3273 Self.Context.getTypeSize(T: DestType)) &&
3274 !DestType->isBooleanType()) {
3275 // C 6.3.2.3p6: Any pointer type may be converted to an integer type.
3276 // Except as previously specified, the result is implementation-defined.
3277 // If the result cannot be represented in the integer type, the behavior
3278 // is undefined. The result need not be in the range of values of any
3279 // integer type.
3280 unsigned Diag;
3281 if (SrcType->isVoidPointerType())
3282 Diag = DestType->isEnumeralType() ? diag::warn_void_pointer_to_enum_cast
3283 : diag::warn_void_pointer_to_int_cast;
3284 else if (DestType->isEnumeralType())
3285 Diag = diag::warn_pointer_to_enum_cast;
3286 else
3287 Diag = diag::warn_pointer_to_int_cast;
3288 Self.Diag(Loc: OpRange.getBegin(), DiagID: Diag) << SrcType << DestType << OpRange;
3289 }
3290 }
3291
3292 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().isAvailableOption(
3293 Ext: "cl_khr_fp16", LO: Self.getLangOpts())) {
3294 if (DestType->isHalfType()) {
3295 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(), DiagID: diag::err_opencl_cast_to_half)
3296 << DestType << SrcExpr.get()->getSourceRange();
3297 SrcExpr = ExprError();
3298 return;
3299 }
3300 }
3301
3302 // ARC imposes extra restrictions on casts.
3303 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) {
3304 checkObjCConversion(CCK: CheckedConversionKind::CStyleCast);
3305 if (SrcExpr.isInvalid())
3306 return;
3307
3308 const PointerType *CastPtr = DestType->getAs<PointerType>();
3309 if (Self.getLangOpts().ObjCAutoRefCount && CastPtr) {
3310 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
3311 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
3312 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
3313 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
3314 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
3315 !CastQuals.compatiblyIncludesObjCLifetime(other: ExprQuals)) {
3316 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(),
3317 DiagID: diag::err_typecheck_incompatible_ownership)
3318 << SrcType << DestType << AssignmentAction::Casting
3319 << SrcExpr.get()->getSourceRange();
3320 return;
3321 }
3322 }
3323 } else if (!Self.ObjC().CheckObjCARCUnavailableWeakConversion(castType: DestType,
3324 ExprType: SrcType)) {
3325 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(),
3326 DiagID: diag::err_arc_convesion_of_weak_unavailable)
3327 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
3328 SrcExpr = ExprError();
3329 return;
3330 }
3331 }
3332
3333 if (unsigned DiagID = checkCastFunctionType(Self, SrcExpr, DestType))
3334 Self.Diag(Loc: OpRange.getBegin(), DiagID) << SrcType << DestType << OpRange;
3335
3336 if (isa<PointerType>(Val: SrcType) && isa<PointerType>(Val: DestType)) {
3337 QualType SrcTy = cast<PointerType>(Val&: SrcType)->getPointeeType();
3338 QualType DestTy = cast<PointerType>(Val&: DestType)->getPointeeType();
3339
3340 const RecordDecl *SrcRD = SrcTy->getAsRecordDecl();
3341 const RecordDecl *DestRD = DestTy->getAsRecordDecl();
3342
3343 if (SrcRD && DestRD && SrcRD->hasAttr<RandomizeLayoutAttr>() &&
3344 SrcRD != DestRD) {
3345 // The struct we are casting the pointer from was randomized.
3346 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_cast_from_randomized_struct)
3347 << SrcType << DestType;
3348 SrcExpr = ExprError();
3349 return;
3350 }
3351 }
3352
3353 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
3354 DiagnoseCallingConvCast(Self, SrcExpr, DstType: DestType, OpRange);
3355 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
3356 Kind = Self.PrepareScalarCast(src&: SrcExpr, destType: DestType);
3357 if (SrcExpr.isInvalid())
3358 return;
3359
3360 if (Kind == CK_BitCast)
3361 checkCastAlign();
3362}
3363
3364void CastOperation::CheckBuiltinBitCast() {
3365 QualType SrcType = SrcExpr.get()->getType();
3366
3367 if (Self.RequireCompleteType(Loc: OpRange.getBegin(), T: DestType,
3368 DiagID: diag::err_typecheck_cast_to_incomplete) ||
3369 Self.RequireCompleteType(Loc: OpRange.getBegin(), T: SrcType,
3370 DiagID: diag::err_incomplete_type)) {
3371 SrcExpr = ExprError();
3372 return;
3373 }
3374
3375 if (SrcExpr.get()->isPRValue())
3376 SrcExpr = Self.CreateMaterializeTemporaryExpr(T: SrcType, Temporary: SrcExpr.get(),
3377 /*IsLValueReference=*/BoundToLvalueReference: false);
3378
3379 CharUnits DestSize = Self.Context.getTypeSizeInChars(T: DestType);
3380 CharUnits SourceSize = Self.Context.getTypeSizeInChars(T: SrcType);
3381 if (DestSize != SourceSize) {
3382 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bit_cast_type_size_mismatch)
3383 << SrcType << DestType << (int)SourceSize.getQuantity()
3384 << (int)DestSize.getQuantity();
3385 SrcExpr = ExprError();
3386 return;
3387 }
3388
3389 if (!DestType.isTriviallyCopyableType(Context: Self.Context)) {
3390 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bit_cast_non_trivially_copyable)
3391 << 1;
3392 SrcExpr = ExprError();
3393 return;
3394 }
3395
3396 if (!SrcType.isTriviallyCopyableType(Context: Self.Context)) {
3397 Self.Diag(Loc: OpRange.getBegin(), DiagID: diag::err_bit_cast_non_trivially_copyable)
3398 << 0;
3399 SrcExpr = ExprError();
3400 return;
3401 }
3402
3403 Kind = CK_LValueToRValueBitCast;
3404}
3405
3406/// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
3407/// const, volatile or both.
3408static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
3409 QualType DestType) {
3410 if (SrcExpr.isInvalid())
3411 return;
3412
3413 QualType SrcType = SrcExpr.get()->getType();
3414 if (!((SrcType->isAnyPointerType() && DestType->isAnyPointerType()) ||
3415 DestType->isLValueReferenceType()))
3416 return;
3417
3418 QualType TheOffendingSrcType, TheOffendingDestType;
3419 Qualifiers CastAwayQualifiers;
3420 if (CastsAwayConstness(Self, SrcType, DestType, CheckCVR: true, CheckObjCLifetime: false,
3421 TheOffendingSrcType: &TheOffendingSrcType, TheOffendingDestType: &TheOffendingDestType,
3422 CastAwayQualifiers: &CastAwayQualifiers) !=
3423 CastAwayConstnessKind::CACK_Similar)
3424 return;
3425
3426 // FIXME: 'restrict' is not properly handled here.
3427 int qualifiers = -1;
3428 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
3429 qualifiers = 0;
3430 } else if (CastAwayQualifiers.hasConst()) {
3431 qualifiers = 1;
3432 } else if (CastAwayQualifiers.hasVolatile()) {
3433 qualifiers = 2;
3434 }
3435 // This is a variant of int **x; const int **y = (const int **)x;
3436 if (qualifiers == -1)
3437 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(), DiagID: diag::warn_cast_qual2)
3438 << SrcType << DestType;
3439 else
3440 Self.Diag(Loc: SrcExpr.get()->getBeginLoc(), DiagID: diag::warn_cast_qual)
3441 << TheOffendingSrcType << TheOffendingDestType << qualifiers;
3442}
3443
3444ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
3445 TypeSourceInfo *CastTypeInfo,
3446 SourceLocation RPLoc,
3447 Expr *CastExpr) {
3448 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
3449 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
3450 Op.OpRange = CastOperation::OpRangeType(LPLoc, LPLoc, CastExpr->getEndLoc());
3451
3452 if (getLangOpts().CPlusPlus) {
3453 Op.CheckCXXCStyleCast(/*FunctionalCast=*/ FunctionalStyle: false,
3454 ListInitialization: isa<InitListExpr>(Val: CastExpr));
3455 } else {
3456 Op.CheckCStyleCast();
3457 }
3458
3459 if (Op.SrcExpr.isInvalid())
3460 return ExprError();
3461
3462 // -Wcast-qual
3463 DiagnoseCastQual(Self&: Op.Self, SrcExpr: Op.SrcExpr, DestType: Op.DestType);
3464
3465 Op.checkQualifiedDestType();
3466
3467 return Op.complete(castExpr: CStyleCastExpr::Create(
3468 Context, T: Op.ResultType, VK: Op.ValueKind, K: Op.Kind, Op: Op.SrcExpr.get(),
3469 BasePath: &Op.BasePath, FPO: CurFPFeatureOverrides(), WrittenTy: CastTypeInfo, L: LPLoc, R: RPLoc));
3470}
3471
3472ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
3473 QualType Type,
3474 SourceLocation LPLoc,
3475 Expr *CastExpr,
3476 SourceLocation RPLoc) {
3477 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
3478 CastOperation Op(*this, Type, CastExpr);
3479 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
3480 Op.OpRange =
3481 CastOperation::OpRangeType(Op.DestRange.getBegin(), LPLoc, RPLoc);
3482
3483 Op.CheckCXXCStyleCast(/*FunctionalCast=*/FunctionalStyle: true, /*ListInit=*/ListInitialization: false);
3484 if (Op.SrcExpr.isInvalid())
3485 return ExprError();
3486
3487 Op.checkQualifiedDestType();
3488
3489 // -Wcast-qual
3490 DiagnoseCastQual(Self&: Op.Self, SrcExpr: Op.SrcExpr, DestType: Op.DestType);
3491
3492 return Op.complete(castExpr: CXXFunctionalCastExpr::Create(
3493 Context, T: Op.ResultType, VK: Op.ValueKind, Written: CastTypeInfo, Kind: Op.Kind,
3494 Op: Op.SrcExpr.get(), Path: &Op.BasePath, FPO: CurFPFeatureOverrides(), LPLoc, RPLoc));
3495}
3496