1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
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 statements.
10//
11//===----------------------------------------------------------------------===//
12
13#include "CheckExprLifetime.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/CXXInheritance.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/DynamicRecursiveASTVisitor.h"
20#include "clang/AST/EvaluatedExprVisitor.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/ExprObjC.h"
23#include "clang/AST/IgnoreExpr.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/StmtObjC.h"
26#include "clang/AST/TypeLoc.h"
27#include "clang/AST/TypeOrdering.h"
28#include "clang/Basic/TargetInfo.h"
29#include "clang/Lex/Preprocessor.h"
30#include "clang/Sema/EnterExpressionEvaluationContext.h"
31#include "clang/Sema/Initialization.h"
32#include "clang/Sema/Lookup.h"
33#include "clang/Sema/Ownership.h"
34#include "clang/Sema/Scope.h"
35#include "clang/Sema/ScopeInfo.h"
36#include "clang/Sema/SemaCUDA.h"
37#include "clang/Sema/SemaHLSL.h"
38#include "clang/Sema/SemaObjC.h"
39#include "clang/Sema/SemaOpenMP.h"
40#include "llvm/ADT/ArrayRef.h"
41#include "llvm/ADT/DenseMap.h"
42#include "llvm/ADT/STLExtras.h"
43#include "llvm/ADT/SmallVector.h"
44#include "llvm/ADT/StringExtras.h"
45
46using namespace clang;
47using namespace sema;
48
49StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
50 if (FE.isInvalid())
51 return StmtError();
52
53 FE = ActOnFinishFullExpr(Expr: FE.get(), CC: FE.get()->getExprLoc(), DiscardedValue);
54 if (FE.isInvalid())
55 return StmtError();
56
57 // C99 6.8.3p2: The expression in an expression statement is evaluated as a
58 // void expression for its side effects. Conversion to void allows any
59 // operand, even incomplete types.
60
61 // Same thing in for stmt first clause (when expr) and third clause.
62 return StmtResult(FE.getAs<Stmt>());
63}
64
65
66StmtResult Sema::ActOnExprStmtError() {
67 DiscardCleanupsInEvaluationContext();
68 return StmtError();
69}
70
71StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
72 bool HasLeadingEmptyMacro) {
73 return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
74}
75
76StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
77 SourceLocation EndLoc) {
78 DeclGroupRef DG = dg.get();
79
80 // If we have an invalid decl, just return an error.
81 if (DG.isNull()) return StmtError();
82
83 return new (Context) DeclStmt(DG, StartLoc, EndLoc);
84}
85
86void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
87 DeclGroupRef DG = dg.get();
88
89 // If we don't have a declaration, or we have an invalid declaration,
90 // just return.
91 if (DG.isNull() || !DG.isSingleDecl())
92 return;
93
94 Decl *decl = DG.getSingleDecl();
95 if (!decl || decl->isInvalidDecl())
96 return;
97
98 // Only variable declarations are permitted.
99 VarDecl *var = dyn_cast<VarDecl>(Val: decl);
100 if (!var) {
101 Diag(Loc: decl->getLocation(), DiagID: diag::err_non_variable_decl_in_for);
102 decl->setInvalidDecl();
103 return;
104 }
105
106 // foreach variables are never actually initialized in the way that
107 // the parser came up with.
108 var->setInit(nullptr);
109
110 // In ARC, we don't need to retain the iteration variable of a fast
111 // enumeration loop. Rather than actually trying to catch that
112 // during declaration processing, we remove the consequences here.
113 if (getLangOpts().ObjCAutoRefCount) {
114 QualType type = var->getType();
115
116 // Only do this if we inferred the lifetime. Inferred lifetime
117 // will show up as a local qualifier because explicit lifetime
118 // should have shown up as an AttributedType instead.
119 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
120 // Add 'const' and mark the variable as pseudo-strong.
121 var->setType(type.withConst());
122 var->setARCPseudoStrong(true);
123 }
124 }
125}
126
127/// Diagnose unused comparisons, both builtin and overloaded operators.
128/// For '==' and '!=', suggest fixits for '=' or '|='.
129///
130/// Adding a cast to void (or other expression wrappers) will prevent the
131/// warning from firing.
132static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
133 SourceLocation Loc;
134 bool CanAssign;
135 enum { Equality, Inequality, Relational, ThreeWay } Kind;
136
137 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(Val: E)) {
138 if (!Op->isComparisonOp())
139 return false;
140
141 if (Op->getOpcode() == BO_EQ)
142 Kind = Equality;
143 else if (Op->getOpcode() == BO_NE)
144 Kind = Inequality;
145 else if (Op->getOpcode() == BO_Cmp)
146 Kind = ThreeWay;
147 else {
148 assert(Op->isRelationalOp());
149 Kind = Relational;
150 }
151 Loc = Op->getOperatorLoc();
152 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
153 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(Val: E)) {
154 switch (Op->getOperator()) {
155 case OO_EqualEqual:
156 Kind = Equality;
157 break;
158 case OO_ExclaimEqual:
159 Kind = Inequality;
160 break;
161 case OO_Less:
162 case OO_Greater:
163 case OO_GreaterEqual:
164 case OO_LessEqual:
165 Kind = Relational;
166 break;
167 case OO_Spaceship:
168 Kind = ThreeWay;
169 break;
170 default:
171 return false;
172 }
173
174 Loc = Op->getOperatorLoc();
175 CanAssign = Op->getArg(Arg: 0)->IgnoreParenImpCasts()->isLValue();
176 } else {
177 // Not a typo-prone comparison.
178 return false;
179 }
180
181 // Suppress warnings when the operator, suspicious as it may be, comes from
182 // a macro expansion.
183 if (S.SourceMgr.isMacroBodyExpansion(Loc))
184 return false;
185
186 S.Diag(Loc, DiagID: diag::warn_unused_comparison)
187 << (unsigned)Kind << E->getSourceRange();
188
189 // If the LHS is a plausible entity to assign to, provide a fixit hint to
190 // correct common typos.
191 if (CanAssign) {
192 if (Kind == Inequality)
193 S.Diag(Loc, DiagID: diag::note_inequality_comparison_to_or_assign)
194 << FixItHint::CreateReplacement(RemoveRange: Loc, Code: "|=");
195 else if (Kind == Equality)
196 S.Diag(Loc, DiagID: diag::note_equality_comparison_to_assign)
197 << FixItHint::CreateReplacement(RemoveRange: Loc, Code: "=");
198 }
199
200 return true;
201}
202
203static bool DiagnoseNoDiscard(Sema &S, const NamedDecl *OffendingDecl,
204 const WarnUnusedResultAttr *A, SourceLocation Loc,
205 SourceRange R1, SourceRange R2, bool IsCtor) {
206 if (!A)
207 return false;
208 StringRef Msg = A->getMessage();
209
210 if (Msg.empty()) {
211 if (OffendingDecl)
212 return S.Diag(Loc, DiagID: diag::warn_unused_return_type)
213 << IsCtor << A << OffendingDecl << false << R1 << R2;
214 if (IsCtor)
215 return S.Diag(Loc, DiagID: diag::warn_unused_constructor)
216 << A << false << R1 << R2;
217 return S.Diag(Loc, DiagID: diag::warn_unused_result) << A << false << R1 << R2;
218 }
219
220 if (OffendingDecl)
221 return S.Diag(Loc, DiagID: diag::warn_unused_return_type)
222 << IsCtor << A << OffendingDecl << true << Msg << R1 << R2;
223 if (IsCtor)
224 return S.Diag(Loc, DiagID: diag::warn_unused_constructor)
225 << A << true << Msg << R1 << R2;
226 return S.Diag(Loc, DiagID: diag::warn_unused_result) << A << true << Msg << R1 << R2;
227}
228
229namespace {
230
231// Diagnoses unused expressions that call functions marked [[nodiscard]],
232// [[gnu::warn_unused_result]] and similar.
233// Additionally, a DiagID can be provided to emit a warning in additional
234// contexts (such as for an unused LHS of a comma expression)
235void DiagnoseUnused(Sema &S, const Expr *E, std::optional<unsigned> DiagID) {
236 bool NoDiscardOnly = !DiagID.has_value();
237
238 // If we are in an unevaluated expression context, then there can be no unused
239 // results because the results aren't expected to be used in the first place.
240 if (S.isUnevaluatedContext())
241 return;
242
243 SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
244 // In most cases, we don't want to warn if the expression is written in a
245 // macro body, or if the macro comes from a system header. If the offending
246 // expression is a call to a function with the warn_unused_result attribute,
247 // we warn no matter the location. Because of the order in which the various
248 // checks need to happen, we factor out the macro-related test here.
249 bool ShouldSuppress = S.SourceMgr.isMacroBodyExpansion(Loc: ExprLoc) ||
250 S.SourceMgr.isInSystemMacro(loc: ExprLoc);
251
252 const Expr *WarnExpr;
253 SourceLocation Loc;
254 SourceRange R1, R2;
255 if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Ctx&: S.Context))
256 return;
257
258 if (!NoDiscardOnly) {
259 // If this is a GNU statement expression expanded from a macro, it is
260 // probably unused because it is a function-like macro that can be used as
261 // either an expression or statement. Don't warn, because it is almost
262 // certainly a false positive.
263 if (isa<StmtExpr>(Val: E) && Loc.isMacroID())
264 return;
265
266 // Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
267 // That macro is frequently used to suppress "unused parameter" warnings,
268 // but its implementation makes clang's -Wunused-value fire. Prevent this.
269 if (isa<ParenExpr>(Val: E->IgnoreImpCasts()) && Loc.isMacroID()) {
270 SourceLocation SpellLoc = Loc;
271 if (S.findMacroSpelling(loc&: SpellLoc, name: "UNREFERENCED_PARAMETER"))
272 return;
273 }
274 }
275
276 // Okay, we have an unused result. Depending on what the base expression is,
277 // we might want to make a more specific diagnostic. Check for one of these
278 // cases now.
279 if (const FullExpr *Temps = dyn_cast<FullExpr>(Val: E))
280 E = Temps->getSubExpr();
281 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(Val: E))
282 E = TempExpr->getSubExpr();
283
284 if (DiagnoseUnusedComparison(S, E))
285 return;
286
287 E = WarnExpr;
288 if (const auto *Cast = dyn_cast<CastExpr>(Val: E))
289 if (Cast->getCastKind() == CK_NoOp ||
290 Cast->getCastKind() == CK_ConstructorConversion ||
291 Cast->getCastKind() == CK_IntegralCast)
292 E = Cast->getSubExpr()->IgnoreImpCasts();
293
294 if (const CallExpr *CE = dyn_cast<CallExpr>(Val: E)) {
295 if (E->getType()->isVoidType())
296 return;
297
298 auto [OffendingDecl, A] = CE->getUnusedResultAttr(Ctx: S.Context);
299 if (DiagnoseNoDiscard(S, OffendingDecl, A, Loc, R1, R2,
300 /*isCtor=*/IsCtor: false))
301 return;
302
303 // If the callee has attribute pure, const, or warn_unused_result, warn with
304 // a more specific message to make it clear what is happening. If the call
305 // is written in a macro body, only warn if it has the warn_unused_result
306 // attribute.
307 if (const Decl *FD = CE->getCalleeDecl()) {
308 if (ShouldSuppress)
309 return;
310 if (FD->hasAttr<PureAttr>()) {
311 S.Diag(Loc, DiagID: diag::warn_unused_call) << R1 << R2 << "pure";
312 return;
313 }
314 if (FD->hasAttr<ConstAttr>()) {
315 S.Diag(Loc, DiagID: diag::warn_unused_call) << R1 << R2 << "const";
316 return;
317 }
318 }
319 } else if (const auto *CE = dyn_cast<CXXConstructExpr>(Val: E)) {
320 auto [OffendingDecl, A] = CE->getUnusedResultAttr(Ctx: S.Context);
321 if (DiagnoseNoDiscard(S, OffendingDecl, A, Loc, R1, R2,
322 /*isCtor=*/IsCtor: true))
323 return;
324 } else if (const auto *ILE = dyn_cast<InitListExpr>(Val: E)) {
325 if (const TagDecl *TD = ILE->getType()->getAsTagDecl()) {
326
327 if (DiagnoseNoDiscard(S, OffendingDecl: TD, A: TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
328 R2, /*isCtor=*/IsCtor: false))
329 return;
330 }
331 } else if (ShouldSuppress)
332 return;
333
334 E = WarnExpr;
335 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(Val: E)) {
336 if (S.getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
337 S.Diag(Loc, DiagID: diag::err_arc_unused_init_message) << R1;
338 return;
339 }
340
341 auto [OffendingDecl, A] = ME->getUnusedResultAttr(Ctx&: S.Context);
342 if (DiagnoseNoDiscard(S, OffendingDecl, A, Loc, R1, R2,
343 /*isCtor=*/IsCtor: false))
344 return;
345 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Val: E)) {
346 const Expr *Source = POE->getSyntacticForm();
347 // Handle the actually selected call of an OpenMP specialized call.
348 if (S.LangOpts.OpenMP && isa<CallExpr>(Val: Source) &&
349 POE->getNumSemanticExprs() == 1 &&
350 isa<CallExpr>(Val: POE->getSemanticExpr(index: 0)))
351 return DiagnoseUnused(S, E: POE->getSemanticExpr(index: 0), DiagID);
352 if (isa<ObjCSubscriptRefExpr>(Val: Source))
353 DiagID = diag::warn_unused_container_subscript_expr;
354 else if (isa<ObjCPropertyRefExpr>(Val: Source))
355 DiagID = diag::warn_unused_property_expr;
356 } else if (const CXXFunctionalCastExpr *FC
357 = dyn_cast<CXXFunctionalCastExpr>(Val: E)) {
358 const Expr *E = FC->getSubExpr();
359 if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(Val: E))
360 E = TE->getSubExpr();
361 if (isa<CXXTemporaryObjectExpr>(Val: E))
362 return;
363 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: E))
364 if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
365 if (!RD->getAttr<WarnUnusedAttr>())
366 return;
367 }
368
369 if (NoDiscardOnly)
370 return;
371
372 // Diagnose "(void*) blah" as a typo for "(void) blah".
373 if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(Val: E)) {
374 TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
375 QualType T = TI->getType();
376
377 // We really do want to use the non-canonical type here.
378 if (T == S.Context.VoidPtrTy) {
379 PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
380
381 S.Diag(Loc, DiagID: diag::warn_unused_voidptr)
382 << FixItHint::CreateRemoval(RemoveRange: TL.getStarLoc());
383 return;
384 }
385 }
386
387 // Tell the user to assign it into a variable to force a volatile load if this
388 // isn't an array.
389 if (E->isGLValue() && E->getType().isVolatileQualified() &&
390 !E->getType()->isArrayType()) {
391 S.Diag(Loc, DiagID: diag::warn_unused_volatile) << R1 << R2;
392 return;
393 }
394
395 // Do not diagnose use of a comma operator in a SFINAE context because the
396 // type of the left operand could be used for SFINAE, so technically it is
397 // *used*.
398 if (DiagID == diag::warn_unused_comma_left_operand && S.isSFINAEContext())
399 return;
400
401 S.DiagIfReachable(Loc, Stmts: llvm::ArrayRef<const Stmt *>(E),
402 PD: S.PDiag(DiagID: *DiagID) << R1 << R2);
403}
404} // namespace
405
406void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
407 if (const LabelStmt *Label = dyn_cast_if_present<LabelStmt>(Val: S))
408 S = Label->getSubStmt();
409
410 const Expr *E = dyn_cast_if_present<Expr>(Val: S);
411 if (!E)
412 return;
413
414 DiagnoseUnused(S&: *this, E, DiagID);
415}
416
417void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
418 PushCompoundScope(IsStmtExpr);
419}
420
421void Sema::ActOnAfterCompoundStatementLeadingPragmas() {
422 if (getCurFPFeatures().isFPConstrained()) {
423 FunctionScopeInfo *FSI = getCurFunction();
424 assert(FSI);
425 FSI->setUsesFPIntrin();
426 }
427}
428
429void Sema::ActOnFinishOfCompoundStmt() {
430 PopCompoundScope();
431}
432
433sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
434 return getCurFunction()->CompoundScopes.back();
435}
436
437StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
438 ArrayRef<Stmt *> Elts, bool isStmtExpr) {
439 const unsigned NumElts = Elts.size();
440
441 // If we're in C mode, check that we don't have any decls after stmts. If
442 // so, emit an extension diagnostic in C89 and potentially a warning in later
443 // versions.
444 const unsigned MixedDeclsCodeID = getLangOpts().C99
445 ? diag::warn_mixed_decls_code
446 : diag::ext_mixed_decls_code;
447 if (!getLangOpts().CPlusPlus && !Diags.isIgnored(DiagID: MixedDeclsCodeID, Loc: L)) {
448 // Note that __extension__ can be around a decl.
449 unsigned i = 0;
450 // Skip over all declarations.
451 for (; i != NumElts && isa<DeclStmt>(Val: Elts[i]); ++i)
452 /*empty*/;
453
454 // We found the end of the list or a statement. Scan for another declstmt.
455 for (; i != NumElts && !isa<DeclStmt>(Val: Elts[i]); ++i)
456 /*empty*/;
457
458 if (i != NumElts) {
459 Decl *D = *cast<DeclStmt>(Val: Elts[i])->decl_begin();
460 Diag(Loc: D->getLocation(), DiagID: MixedDeclsCodeID);
461 }
462 }
463
464 // Check for suspicious empty body (null statement) in `for' and `while'
465 // statements. Don't do anything for template instantiations, this just adds
466 // noise.
467 if (NumElts != 0 && !CurrentInstantiationScope &&
468 getCurCompoundScope().HasEmptyLoopBodies) {
469 for (unsigned i = 0; i != NumElts - 1; ++i)
470 DiagnoseEmptyLoopBody(S: Elts[i], PossibleBody: Elts[i + 1]);
471 }
472
473 // Calculate difference between FP options in this compound statement and in
474 // the enclosing one. If this is a function body, take the difference against
475 // default options. In this case the difference will indicate options that are
476 // changed upon entry to the statement.
477 FPOptions FPO = (getCurFunction()->CompoundScopes.size() == 1)
478 ? FPOptions(getLangOpts())
479 : getCurCompoundScope().InitialFPFeatures;
480 FPOptionsOverride FPDiff = getCurFPFeatures().getChangesFrom(Base: FPO);
481
482 return CompoundStmt::Create(C: Context, Stmts: Elts, FPFeatures: FPDiff, LB: L, RB: R);
483}
484
485ExprResult
486Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
487 if (!Val.get())
488 return Val;
489
490 if (DiagnoseUnexpandedParameterPack(E: Val.get()))
491 return ExprError();
492
493 // If we're not inside a switch, let the 'case' statement handling diagnose
494 // this. Just clean up after the expression as best we can.
495 if (getCurFunction()->SwitchStack.empty())
496 return ActOnFinishFullExpr(Expr: Val.get(), CC: Val.get()->getExprLoc(), DiscardedValue: false,
497 IsConstexpr: getLangOpts().CPlusPlus11);
498
499 Expr *CondExpr =
500 getCurFunction()->SwitchStack.back().getPointer()->getCond();
501 if (!CondExpr)
502 return ExprError();
503 QualType CondType = CondExpr->getType();
504
505 auto CheckAndFinish = [&](Expr *E) {
506 if (CondType->isDependentType() || E->isTypeDependent())
507 return ExprResult(E);
508
509 if (getLangOpts().CPlusPlus11) {
510 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
511 // constant expression of the promoted type of the switch condition.
512 llvm::APSInt TempVal;
513 return CheckConvertedConstantExpression(From: E, T: CondType, Value&: TempVal,
514 CCE: CCEKind::CaseValue);
515 }
516
517 ExprResult ER = E;
518 if (!E->isValueDependent())
519 ER = VerifyIntegerConstantExpression(E, CanFold: AllowFoldKind::Allow);
520 if (!ER.isInvalid())
521 ER = DefaultLvalueConversion(E: ER.get());
522 if (!ER.isInvalid())
523 ER = ImpCastExprToType(E: ER.get(), Type: CondType, CK: CK_IntegralCast);
524 if (!ER.isInvalid())
525 ER = ActOnFinishFullExpr(Expr: ER.get(), CC: ER.get()->getExprLoc(), DiscardedValue: false);
526 return ER;
527 };
528
529 return CheckAndFinish(Val.get());
530}
531
532static bool DiagnoseSwitchCaseInExpansionStmt(Sema &S, SourceLocation KwLoc,
533 bool IsDefault) {
534 // C++26 [stmt.expand] The compound-statement of an expansion-statement is a
535 // control-flow-limited statement.
536 //
537 // We diagnose this here rather than in JumpDiagnostics because those run
538 // after the expansion statement is instantiated, at which point we will have
539 // have already complained about duplicate case labels, which is not exactly
540 // great QOI.
541 if (S.CurContext->isExpansionStmt() &&
542 S.getCurFunction()->SwitchStack.back().EnclosingDC != S.CurContext) {
543 S.Diag(Loc: KwLoc, DiagID: diag::err_expansion_stmt_case) << IsDefault;
544 S.Diag(Loc: S.getCurFunction()->SwitchStack.back().getPointer()->getSwitchLoc(),
545 DiagID: diag::note_enclosing_switch_statement_here);
546 return true;
547 }
548 return false;
549}
550
551StmtResult
552Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
553 SourceLocation DotDotDotLoc, ExprResult RHSVal,
554 SourceLocation ColonLoc) {
555 assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value");
556 assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()
557 : RHSVal.isInvalid() || RHSVal.get()) &&
558 "missing RHS value");
559
560 if (getCurFunction()->SwitchStack.empty()) {
561 Diag(Loc: CaseLoc, DiagID: diag::err_case_not_in_switch);
562 return StmtError();
563 }
564
565 if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
566 getCurFunction()->SwitchStack.back().setInt(true);
567 return StmtError();
568 }
569
570 if (DiagnoseSwitchCaseInExpansionStmt(S&: *this, KwLoc: CaseLoc, IsDefault: false))
571 return StmtError();
572
573 if (LangOpts.OpenACC &&
574 getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
575 Diag(Loc: CaseLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
576 << /*branch*/ 0 << /*into*/ 1;
577 return StmtError();
578 }
579
580 auto *CS = CaseStmt::Create(Ctx: Context, lhs: LHSVal.get(), rhs: RHSVal.get(),
581 caseLoc: CaseLoc, ellipsisLoc: DotDotDotLoc, colonLoc: ColonLoc);
582 getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: CS);
583 return CS;
584}
585
586void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
587 cast<CaseStmt>(Val: S)->setSubStmt(SubStmt);
588}
589
590StmtResult
591Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
592 Stmt *SubStmt, Scope *CurScope) {
593 if (getCurFunction()->SwitchStack.empty()) {
594 Diag(Loc: DefaultLoc, DiagID: diag::err_default_not_in_switch);
595 return SubStmt;
596 }
597
598 if (DiagnoseSwitchCaseInExpansionStmt(S&: *this, KwLoc: DefaultLoc, IsDefault: true))
599 return StmtError();
600
601 if (LangOpts.OpenACC &&
602 getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
603 Diag(Loc: DefaultLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
604 << /*branch*/ 0 << /*into*/ 1;
605 return StmtError();
606 }
607
608 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
609 getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: DS);
610 return DS;
611}
612
613StmtResult
614Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
615 SourceLocation ColonLoc, Stmt *SubStmt) {
616 // If the label was multiply defined, reject it now.
617 if (TheDecl->getStmt()) {
618 Diag(Loc: IdentLoc, DiagID: diag::err_redefinition_of_label) << TheDecl->getDeclName();
619 Diag(Loc: TheDecl->getLocation(), DiagID: diag::note_previous_definition);
620 return SubStmt;
621 }
622
623 ReservedIdentifierStatus Status = TheDecl->isReserved(LangOpts: getLangOpts());
624 if (isReservedInAllContexts(Status) &&
625 !Context.getSourceManager().isInSystemHeader(Loc: IdentLoc))
626 Diag(Loc: IdentLoc, DiagID: diag::warn_reserved_extern_symbol)
627 << TheDecl << static_cast<int>(Status);
628
629 // If this label is in a compute construct scope, we need to make sure we
630 // check gotos in/out.
631 if (getCurScope()->isInOpenACCComputeConstructScope())
632 setFunctionHasBranchProtectedScope();
633
634 // OpenACC3.3 2.14.4:
635 // The update directive is executable. It must not appear in place of the
636 // statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
637 // C++.
638 if (isa<OpenACCUpdateConstruct>(Val: SubStmt)) {
639 Diag(Loc: SubStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*Label*/ 4;
640 SubStmt = new (Context) NullStmt(SubStmt->getBeginLoc());
641 }
642
643 // Otherwise, things are good. Fill in the declaration and return it.
644 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
645 TheDecl->setStmt(LS);
646 if (!TheDecl->isGnuLocal()) {
647 TheDecl->setLocStart(IdentLoc);
648 if (!TheDecl->isMSAsmLabel()) {
649 // Don't update the location of MS ASM labels. These will result in
650 // a diagnostic, and changing the location here will mess that up.
651 TheDecl->setLocation(IdentLoc);
652 }
653 }
654 return LS;
655}
656
657StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
658 ArrayRef<const Attr *> Attrs,
659 Stmt *SubStmt) {
660 // FIXME: this code should move when a planned refactoring around statement
661 // attributes lands.
662 for (const auto *A : Attrs) {
663 if (A->getKind() == attr::MustTail) {
664 if (!checkAndRewriteMustTailAttr(St: SubStmt, MTA: *A)) {
665 return SubStmt;
666 }
667 setFunctionHasMustTail();
668 }
669 }
670
671 return AttributedStmt::Create(C: Context, Loc: AttrsLoc, Attrs, SubStmt);
672}
673
674StmtResult Sema::ActOnAttributedStmt(const ParsedAttributes &Attrs,
675 Stmt *SubStmt) {
676 SmallVector<const Attr *, 1> SemanticAttrs;
677 ProcessStmtAttributes(Stmt: SubStmt, InAttrs: Attrs, OutAttrs&: SemanticAttrs);
678 if (!SemanticAttrs.empty())
679 return BuildAttributedStmt(AttrsLoc: Attrs.Range.getBegin(), Attrs: SemanticAttrs, SubStmt);
680 // If none of the attributes applied, that's fine, we can recover by
681 // returning the substatement directly instead of making an AttributedStmt
682 // with no attributes on it.
683 return SubStmt;
684}
685
686bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
687 ReturnStmt *R = cast<ReturnStmt>(Val: St);
688 Expr *E = R->getRetValue();
689
690 if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
691 // We have to suspend our check until template instantiation time.
692 return true;
693
694 if (!checkMustTailAttr(St, MTA))
695 return false;
696
697 // FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
698 // Currently it does not skip implicit constructors in an initialization
699 // context.
700 auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
701 return IgnoreExprNodes(E, Fns&: IgnoreImplicitAsWrittenSingleStep,
702 Fns&: IgnoreElidableImplicitConstructorSingleStep);
703 };
704
705 // Now that we have verified that 'musttail' is valid here, rewrite the
706 // return value to remove all implicit nodes, but retain parentheses.
707 R->setRetValue(IgnoreImplicitAsWritten(E));
708 return true;
709}
710
711bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
712 assert(!CurContext->isDependentContext() &&
713 "musttail cannot be checked from a dependent context");
714
715 // FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
716 auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
717 return IgnoreExprNodes(E: const_cast<Expr *>(E), Fns&: IgnoreParensSingleStep,
718 Fns&: IgnoreImplicitAsWrittenSingleStep,
719 Fns&: IgnoreElidableImplicitConstructorSingleStep);
720 };
721
722 const Expr *E = cast<ReturnStmt>(Val: St)->getRetValue();
723 const auto *CE = dyn_cast_or_null<CallExpr>(Val: IgnoreParenImplicitAsWritten(E));
724
725 if (!CE) {
726 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_call) << &MTA;
727 return false;
728 }
729
730 if (const FunctionDecl *CalleeDecl = CE->getDirectCallee();
731 CalleeDecl && CalleeDecl->hasAttr<NotTailCalledAttr>()) {
732 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch) << /*show-function-callee=*/true << CalleeDecl;
733 Diag(Loc: CalleeDecl->getLocation(), DiagID: diag::note_musttail_disabled_by_not_tail_called);
734 return false;
735 }
736
737 if (const auto *EWC = dyn_cast<ExprWithCleanups>(Val: E)) {
738 if (EWC->cleanupsHaveSideEffects()) {
739 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_trivial_args) << &MTA;
740 return false;
741 }
742 }
743
744 // We need to determine the full function type (including "this" type, if any)
745 // for both caller and callee.
746 struct FuncType {
747 enum {
748 ft_non_member,
749 ft_static_member,
750 ft_non_static_member,
751 ft_pointer_to_member,
752 } MemberType = ft_non_member;
753
754 QualType This;
755 const FunctionProtoType *Func;
756 const CXXMethodDecl *Method = nullptr;
757 } CallerType, CalleeType;
758
759 auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
760 bool IsCallee) -> bool {
761 if (isa<CXXConstructorDecl, CXXDestructorDecl>(Val: CMD)) {
762 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_structors_forbidden)
763 << IsCallee << isa<CXXDestructorDecl>(Val: CMD);
764 if (IsCallee)
765 Diag(Loc: CMD->getBeginLoc(), DiagID: diag::note_musttail_structors_forbidden)
766 << isa<CXXDestructorDecl>(Val: CMD);
767 Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
768 return false;
769 }
770 if (CMD->isStatic())
771 Type.MemberType = FuncType::ft_static_member;
772 else {
773 Type.This = CMD->getFunctionObjectParameterType();
774 Type.MemberType = FuncType::ft_non_static_member;
775 }
776 Type.Func = CMD->getType()->castAs<FunctionProtoType>();
777 return true;
778 };
779
780 const auto *CallerDecl = dyn_cast<FunctionDecl>(Val: CurContext);
781
782 // Find caller function signature.
783 if (!CallerDecl) {
784 int ContextType;
785 if (isa<BlockDecl>(Val: CurContext))
786 ContextType = 0;
787 else if (isa<ObjCMethodDecl>(Val: CurContext))
788 ContextType = 1;
789 else
790 ContextType = 2;
791 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_forbidden_from_this_context)
792 << &MTA << ContextType;
793 return false;
794 } else if (const auto *CMD = dyn_cast<CXXMethodDecl>(Val: CurContext)) {
795 // Caller is a class/struct method.
796 if (!GetMethodType(CMD, CallerType, false))
797 return false;
798 } else {
799 // Caller is a non-method function.
800 CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
801 }
802
803 const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
804 const auto *CalleeBinOp = dyn_cast<BinaryOperator>(Val: CalleeExpr);
805 SourceLocation CalleeLoc = CE->getCalleeDecl()
806 ? CE->getCalleeDecl()->getBeginLoc()
807 : St->getBeginLoc();
808
809 // Find callee function signature.
810 if (const CXXMethodDecl *CMD =
811 dyn_cast_or_null<CXXMethodDecl>(Val: CE->getCalleeDecl())) {
812 // Call is: obj.method(), obj->method(), functor(), etc.
813 if (!GetMethodType(CMD, CalleeType, true))
814 return false;
815 } else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
816 // Call is: obj->*method_ptr or obj.*method_ptr
817 const auto *MPT =
818 CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
819 CalleeType.This =
820 Context.getCanonicalTagType(TD: MPT->getMostRecentCXXRecordDecl());
821 CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
822 CalleeType.MemberType = FuncType::ft_pointer_to_member;
823 } else if (isa<CXXPseudoDestructorExpr>(Val: CalleeExpr)) {
824 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_structors_forbidden)
825 << /* IsCallee = */ 1 << /* IsDestructor = */ 1;
826 Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
827 return false;
828 } else {
829 // Non-method function.
830 CalleeType.Func =
831 CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
832 }
833
834 // Both caller and callee must have a prototype (no K&R declarations).
835 if (!CalleeType.Func || !CallerType.Func) {
836 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_prototype) << &MTA;
837 if (!CalleeType.Func && CE->getDirectCallee()) {
838 Diag(Loc: CE->getDirectCallee()->getBeginLoc(),
839 DiagID: diag::note_musttail_fix_non_prototype);
840 }
841 if (!CallerType.Func)
842 Diag(Loc: CallerDecl->getBeginLoc(), DiagID: diag::note_musttail_fix_non_prototype);
843 return false;
844 }
845
846 // Caller and callee must have matching calling conventions.
847 //
848 // Some calling conventions are physically capable of supporting tail calls
849 // even if the function types don't perfectly match. LLVM is currently too
850 // strict to allow this, but if LLVM added support for this in the future, we
851 // could exit early here and skip the remaining checks if the functions are
852 // using such a calling convention.
853 if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
854 if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl()))
855 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_callconv_mismatch)
856 << true << ND->getDeclName();
857 else
858 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_callconv_mismatch) << false;
859 Diag(Loc: CalleeLoc, DiagID: diag::note_musttail_callconv_mismatch)
860 << FunctionType::getNameForCallConv(CC: CallerType.Func->getCallConv())
861 << FunctionType::getNameForCallConv(CC: CalleeType.Func->getCallConv());
862 Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
863 return false;
864 }
865
866 if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
867 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_no_variadic) << &MTA;
868 return false;
869 }
870
871 const auto *CalleeDecl = CE->getCalleeDecl();
872 if (CalleeDecl && CalleeDecl->hasAttr<CXX11NoReturnAttr>()) {
873 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_no_return) << &MTA;
874 return false;
875 }
876
877 // Caller and callee must match in whether they have a "this" parameter.
878 if (CallerType.This.isNull() != CalleeType.This.isNull()) {
879 if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl())) {
880 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_member_mismatch)
881 << CallerType.MemberType << CalleeType.MemberType << true
882 << ND->getDeclName();
883 Diag(Loc: CalleeLoc, DiagID: diag::note_musttail_callee_defined_here)
884 << ND->getDeclName();
885 } else
886 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_member_mismatch)
887 << CallerType.MemberType << CalleeType.MemberType << false;
888 Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
889 return false;
890 }
891
892 auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
893 PartialDiagnostic &PD) -> bool {
894 enum {
895 ft_different_class,
896 ft_parameter_arity,
897 ft_parameter_mismatch,
898 ft_return_type,
899 };
900
901 auto DoTypesMatch = [this, &PD](QualType A, QualType B,
902 unsigned Select) -> bool {
903 if (!Context.hasSimilarType(T1: A, T2: B)) {
904 PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
905 return false;
906 }
907 return true;
908 };
909
910 if (!CallerType.This.isNull() &&
911 !DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
912 return false;
913
914 if (!DoTypesMatch(CallerType.Func->getReturnType(),
915 CalleeType.Func->getReturnType(), ft_return_type))
916 return false;
917
918 if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
919 PD << ft_parameter_arity << CallerType.Func->getNumParams()
920 << CalleeType.Func->getNumParams();
921 return false;
922 }
923
924 ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
925 ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
926 size_t N = CallerType.Func->getNumParams();
927 for (size_t I = 0; I < N; I++) {
928 if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
929 ft_parameter_mismatch)) {
930 PD << static_cast<int>(I) + 1;
931 return false;
932 }
933 }
934
935 return true;
936 };
937
938 PartialDiagnostic PD = PDiag(DiagID: diag::note_musttail_mismatch);
939 if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
940 if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl()))
941 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch)
942 << true << ND->getDeclName();
943 else
944 Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch) << false;
945 Diag(Loc: CalleeLoc, PD);
946 Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
947 return false;
948 }
949
950 // The lifetimes of locals and incoming function parameters must end before
951 // the call, because we can't have a stack frame to store them, so diagnose
952 // any pointers or references to them passed into the musttail call.
953 for (auto ArgExpr : CE->arguments()) {
954 InitializedEntity Entity = InitializedEntity::InitializeParameter(
955 Context, Type: ArgExpr->getType(), Consumed: false);
956 checkExprLifetimeMustTailArg(SemaRef&: *this, Entity, Init: const_cast<Expr *>(ArgExpr));
957 }
958
959 return true;
960}
961
962namespace {
963class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
964 typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
965 Sema &SemaRef;
966public:
967 CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
968 void VisitBinaryOperator(BinaryOperator *E) {
969 if (E->getOpcode() == BO_Comma)
970 SemaRef.DiagnoseCommaOperator(LHS: E->getLHS(), Loc: E->getExprLoc());
971 EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(S: E);
972 }
973};
974}
975
976StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc,
977 IfStatementKind StatementKind,
978 SourceLocation LParenLoc, Stmt *InitStmt,
979 ConditionResult Cond, SourceLocation RParenLoc,
980 Stmt *thenStmt, SourceLocation ElseLoc,
981 Stmt *elseStmt) {
982 if (Cond.isInvalid())
983 return StmtError();
984
985 bool ConstevalOrNegatedConsteval =
986 StatementKind == IfStatementKind::ConstevalNonNegated ||
987 StatementKind == IfStatementKind::ConstevalNegated;
988
989 Expr *CondExpr = Cond.get().second;
990 assert((CondExpr || ConstevalOrNegatedConsteval) &&
991 "If statement: missing condition");
992 // Only call the CommaVisitor when not C89 due to differences in scope flags.
993 if (CondExpr && (getLangOpts().C99 || getLangOpts().CPlusPlus) &&
994 !Diags.isIgnored(DiagID: diag::warn_comma_operator, Loc: CondExpr->getExprLoc()))
995 CommaVisitor(*this).Visit(S: CondExpr);
996
997 if (!ConstevalOrNegatedConsteval && !elseStmt)
998 DiagnoseEmptyStmtBody(StmtLoc: RParenLoc, Body: thenStmt, DiagID: diag::warn_empty_if_body);
999
1000 if (ConstevalOrNegatedConsteval ||
1001 StatementKind == IfStatementKind::Constexpr) {
1002 auto DiagnoseLikelihood = [&](const Stmt *S) {
1003 if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
1004 Diags.Report(Loc: A->getLocation(),
1005 DiagID: diag::warn_attribute_has_no_effect_on_compile_time_if)
1006 << A << ConstevalOrNegatedConsteval << A->getRange();
1007 Diags.Report(Loc: IfLoc,
1008 DiagID: diag::note_attribute_has_no_effect_on_compile_time_if_here)
1009 << ConstevalOrNegatedConsteval
1010 << SourceRange(IfLoc, (ConstevalOrNegatedConsteval
1011 ? thenStmt->getBeginLoc()
1012 : LParenLoc)
1013 .getLocWithOffset(Offset: -1));
1014 }
1015 };
1016 DiagnoseLikelihood(thenStmt);
1017 DiagnoseLikelihood(elseStmt);
1018 } else {
1019 std::tuple<bool, const Attr *, const Attr *> LHC =
1020 Stmt::determineLikelihoodConflict(Then: thenStmt, Else: elseStmt);
1021 if (std::get<0>(t&: LHC)) {
1022 const Attr *ThenAttr = std::get<1>(t&: LHC);
1023 const Attr *ElseAttr = std::get<2>(t&: LHC);
1024 Diags.Report(Loc: ThenAttr->getLocation(),
1025 DiagID: diag::warn_attributes_likelihood_ifstmt_conflict)
1026 << ThenAttr << ThenAttr->getRange();
1027 Diags.Report(Loc: ElseAttr->getLocation(), DiagID: diag::note_conflicting_attribute)
1028 << ElseAttr << ElseAttr->getRange();
1029 }
1030 }
1031
1032 if (ConstevalOrNegatedConsteval) {
1033 bool Immediate = ExprEvalContexts.back().Context ==
1034 ExpressionEvaluationContext::ImmediateFunctionContext;
1035 if (CurContext->isFunctionOrMethod()) {
1036 const auto *FD =
1037 dyn_cast<FunctionDecl>(Val: Decl::castFromDeclContext(CurContext));
1038 if (FD && FD->isImmediateFunction())
1039 Immediate = true;
1040 }
1041 if (isUnevaluatedContext() || Immediate)
1042 Diags.Report(Loc: IfLoc, DiagID: diag::warn_consteval_if_always_true) << Immediate;
1043 }
1044
1045 // OpenACC3.3 2.14.4:
1046 // The update directive is executable. It must not appear in place of the
1047 // statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1048 // C++.
1049 if (isa<OpenACCUpdateConstruct>(Val: thenStmt)) {
1050 Diag(Loc: thenStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*if*/ 0;
1051 thenStmt = new (Context) NullStmt(thenStmt->getBeginLoc());
1052 }
1053
1054 return BuildIfStmt(IfLoc, StatementKind, LParenLoc, InitStmt, Cond, RParenLoc,
1055 ThenVal: thenStmt, ElseLoc, ElseVal: elseStmt);
1056}
1057
1058StmtResult Sema::BuildIfStmt(SourceLocation IfLoc,
1059 IfStatementKind StatementKind,
1060 SourceLocation LParenLoc, Stmt *InitStmt,
1061 ConditionResult Cond, SourceLocation RParenLoc,
1062 Stmt *thenStmt, SourceLocation ElseLoc,
1063 Stmt *elseStmt) {
1064 if (Cond.isInvalid())
1065 return StmtError();
1066
1067 if (StatementKind != IfStatementKind::Ordinary ||
1068 isa<ObjCAvailabilityCheckExpr>(Val: Cond.get().second))
1069 setFunctionHasBranchProtectedScope();
1070
1071 return IfStmt::Create(Ctx: Context, IL: IfLoc, Kind: StatementKind, Init: InitStmt,
1072 Var: Cond.get().first, Cond: Cond.get().second, LPL: LParenLoc,
1073 RPL: RParenLoc, Then: thenStmt, EL: ElseLoc, Else: elseStmt);
1074}
1075
1076namespace {
1077 struct CaseCompareFunctor {
1078 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1079 const llvm::APSInt &RHS) {
1080 return LHS.first < RHS;
1081 }
1082 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1083 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1084 return LHS.first < RHS.first;
1085 }
1086 bool operator()(const llvm::APSInt &LHS,
1087 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1088 return LHS < RHS.first;
1089 }
1090 };
1091}
1092
1093/// CmpCaseVals - Comparison predicate for sorting case values.
1094///
1095static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
1096 const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
1097 if (lhs.first < rhs.first)
1098 return true;
1099
1100 if (lhs.first == rhs.first &&
1101 lhs.second->getCaseLoc() < rhs.second->getCaseLoc())
1102 return true;
1103 return false;
1104}
1105
1106/// CmpEnumVals - Comparison predicate for sorting enumeration values.
1107///
1108static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1109 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1110{
1111 return lhs.first < rhs.first;
1112}
1113
1114/// EqEnumVals - Comparison preficate for uniqing enumeration values.
1115///
1116static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1117 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1118{
1119 return lhs.first == rhs.first;
1120}
1121
1122/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
1123/// potentially integral-promoted expression @p expr.
1124static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
1125 if (const auto *FE = dyn_cast<FullExpr>(Val: E))
1126 E = FE->getSubExpr();
1127 while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(Val: E)) {
1128 if (ImpCast->getCastKind() != CK_IntegralCast) break;
1129 E = ImpCast->getSubExpr();
1130 }
1131 return E->getType();
1132}
1133
1134ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
1135 class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
1136 Expr *Cond;
1137
1138 public:
1139 SwitchConvertDiagnoser(Expr *Cond)
1140 : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
1141 Cond(Cond) {}
1142
1143 SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
1144 QualType T) override {
1145 return S.Diag(Loc, DiagID: diag::err_typecheck_statement_requires_integer) << T;
1146 }
1147
1148 SemaDiagnosticBuilder diagnoseIncomplete(
1149 Sema &S, SourceLocation Loc, QualType T) override {
1150 return S.Diag(Loc, DiagID: diag::err_switch_incomplete_class_type)
1151 << T << Cond->getSourceRange();
1152 }
1153
1154 SemaDiagnosticBuilder diagnoseExplicitConv(
1155 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1156 return S.Diag(Loc, DiagID: diag::err_switch_explicit_conversion) << T << ConvTy;
1157 }
1158
1159 SemaDiagnosticBuilder noteExplicitConv(
1160 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1161 return S.Diag(Loc: Conv->getLocation(), DiagID: diag::note_switch_conversion)
1162 << ConvTy->isEnumeralType() << ConvTy;
1163 }
1164
1165 SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
1166 QualType T) override {
1167 return S.Diag(Loc, DiagID: diag::err_switch_multiple_conversions) << T;
1168 }
1169
1170 SemaDiagnosticBuilder noteAmbiguous(
1171 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1172 return S.Diag(Loc: Conv->getLocation(), DiagID: diag::note_switch_conversion)
1173 << ConvTy->isEnumeralType() << ConvTy;
1174 }
1175
1176 SemaDiagnosticBuilder diagnoseConversion(
1177 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1178 llvm_unreachable("conversion functions are permitted");
1179 }
1180 } SwitchDiagnoser(Cond);
1181
1182 ExprResult CondResult =
1183 PerformContextualImplicitConversion(Loc: SwitchLoc, FromE: Cond, Converter&: SwitchDiagnoser);
1184 if (CondResult.isInvalid())
1185 return ExprError();
1186
1187 // FIXME: PerformContextualImplicitConversion doesn't always tell us if it
1188 // failed and produced a diagnostic.
1189 Cond = CondResult.get();
1190 if (!Cond->isTypeDependent() &&
1191 !Cond->getType()->isIntegralOrEnumerationType())
1192 return ExprError();
1193
1194 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
1195 return UsualUnaryConversions(E: Cond);
1196}
1197
1198StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
1199 SourceLocation LParenLoc,
1200 Stmt *InitStmt, ConditionResult Cond,
1201 SourceLocation RParenLoc) {
1202 Expr *CondExpr = Cond.get().second;
1203 assert((Cond.isInvalid() || CondExpr) && "switch with no condition");
1204
1205 if (CondExpr && !CondExpr->isTypeDependent()) {
1206 // We have already converted the expression to an integral or enumeration
1207 // type, when we parsed the switch condition. There are cases where we don't
1208 // have an appropriate type, e.g. a typo-expr Cond was corrected to an
1209 // inappropriate-type expr, we just return an error.
1210 if (!CondExpr->getType()->isIntegralOrEnumerationType())
1211 return StmtError();
1212 if (CondExpr->isKnownToHaveBooleanValue()) {
1213 // switch(bool_expr) {...} is often a programmer error, e.g.
1214 // switch(n && mask) { ... } // Doh - should be "n & mask".
1215 // One can always use an if statement instead of switch(bool_expr).
1216 Diag(Loc: SwitchLoc, DiagID: diag::warn_bool_switch_condition)
1217 << CondExpr->getSourceRange();
1218 }
1219 }
1220
1221 setFunctionHasBranchIntoScope();
1222
1223 auto *SS = SwitchStmt::Create(Ctx: Context, Init: InitStmt, Var: Cond.get().first, Cond: CondExpr,
1224 LParenLoc, RParenLoc);
1225 SS->setSwitchLoc(SwitchLoc);
1226 getCurFunction()->SwitchStack.push_back(
1227 Elt: FunctionScopeInfo::SwitchInfo(SS, CurContext));
1228 return SS;
1229}
1230
1231static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
1232 Val = Val.extOrTrunc(width: BitWidth);
1233 Val.setIsSigned(IsSigned);
1234}
1235
1236/// Check the specified case value is in range for the given unpromoted switch
1237/// type.
1238static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
1239 unsigned UnpromotedWidth, bool UnpromotedSign) {
1240 // In C++11 onwards, this is checked by the language rules.
1241 if (S.getLangOpts().CPlusPlus11)
1242 return;
1243
1244 // If the case value was signed and negative and the switch expression is
1245 // unsigned, don't bother to warn: this is implementation-defined behavior.
1246 // FIXME: Introduce a second, default-ignored warning for this case?
1247 if (UnpromotedWidth < Val.getBitWidth()) {
1248 llvm::APSInt ConvVal(Val);
1249 AdjustAPSInt(Val&: ConvVal, BitWidth: UnpromotedWidth, IsSigned: UnpromotedSign);
1250 AdjustAPSInt(Val&: ConvVal, BitWidth: Val.getBitWidth(), IsSigned: Val.isSigned());
1251 // FIXME: Use different diagnostics for overflow in conversion to promoted
1252 // type versus "switch expression cannot have this value". Use proper
1253 // IntRange checking rather than just looking at the unpromoted type here.
1254 if (ConvVal != Val)
1255 S.Diag(Loc, DiagID: diag::warn_case_value_overflow) << toString(I: Val, Radix: 10)
1256 << toString(I: ConvVal, Radix: 10);
1257 }
1258}
1259
1260typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
1261
1262/// Returns true if we should emit a diagnostic about this case expression not
1263/// being a part of the enum used in the switch controlling expression.
1264static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
1265 const EnumDecl *ED,
1266 const Expr *CaseExpr,
1267 EnumValsTy::iterator &EI,
1268 EnumValsTy::iterator &EIEnd,
1269 const llvm::APSInt &Val) {
1270 if (!ED->isClosed())
1271 return false;
1272
1273 if (const DeclRefExpr *DRE =
1274 dyn_cast<DeclRefExpr>(Val: CaseExpr->IgnoreParenImpCasts())) {
1275 if (const VarDecl *VD = dyn_cast<VarDecl>(Val: DRE->getDecl())) {
1276 QualType VarType = VD->getType();
1277 CanQualType EnumType = S.Context.getCanonicalTagType(TD: ED);
1278 if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
1279 S.Context.hasSameUnqualifiedType(T1: EnumType, T2: VarType))
1280 return false;
1281 }
1282 }
1283
1284 if (ED->hasAttr<FlagEnumAttr>())
1285 return !S.IsValueInFlagEnum(ED, Val, AllowMask: false);
1286
1287 while (EI != EIEnd && EI->first < Val)
1288 EI++;
1289
1290 if (EI != EIEnd && EI->first == Val)
1291 return false;
1292
1293 return true;
1294}
1295
1296static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
1297 const Expr *Case) {
1298 QualType CondType = Cond->getType();
1299 QualType CaseType = Case->getType();
1300
1301 const EnumType *CondEnumType = CondType->getAsCanonical<EnumType>();
1302 const EnumType *CaseEnumType = CaseType->getAsCanonical<EnumType>();
1303 if (!CondEnumType || !CaseEnumType)
1304 return;
1305
1306 // Ignore anonymous enums.
1307 if (!CondEnumType->getDecl()->getIdentifier() &&
1308 !CondEnumType->getDecl()->getTypedefNameForAnonDecl())
1309 return;
1310 if (!CaseEnumType->getDecl()->getIdentifier() &&
1311 !CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
1312 return;
1313
1314 if (S.Context.hasSameUnqualifiedType(T1: CondType, T2: CaseType))
1315 return;
1316
1317 S.Diag(Loc: Case->getExprLoc(), DiagID: diag::warn_comparison_of_mixed_enum_types_switch)
1318 << CondType << CaseType << Cond->getSourceRange()
1319 << Case->getSourceRange();
1320}
1321
1322StmtResult
1323Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
1324 Stmt *BodyStmt) {
1325 SwitchStmt *SS = cast<SwitchStmt>(Val: Switch);
1326 bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
1327 assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&
1328 "switch stack missing push/pop!");
1329
1330 getCurFunction()->SwitchStack.pop_back();
1331
1332 if (!BodyStmt) return StmtError();
1333
1334 // OpenACC3.3 2.14.4:
1335 // The update directive is executable. It must not appear in place of the
1336 // statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1337 // C++.
1338 if (isa<OpenACCUpdateConstruct>(Val: BodyStmt)) {
1339 Diag(Loc: BodyStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*switch*/ 3;
1340 BodyStmt = new (Context) NullStmt(BodyStmt->getBeginLoc());
1341 }
1342
1343 SS->setBody(BodyStmt);
1344
1345 Expr *CondExpr = SS->getCond();
1346 if (!CondExpr) return StmtError();
1347
1348 QualType CondType = CondExpr->getType();
1349
1350 // C++ 6.4.2.p2:
1351 // Integral promotions are performed (on the switch condition).
1352 //
1353 // A case value unrepresentable by the original switch condition
1354 // type (before the promotion) doesn't make sense, even when it can
1355 // be represented by the promoted type. Therefore we need to find
1356 // the pre-promotion type of the switch condition.
1357 const Expr *CondExprBeforePromotion = CondExpr;
1358 QualType CondTypeBeforePromotion =
1359 GetTypeBeforeIntegralPromotion(E&: CondExprBeforePromotion);
1360
1361 // Get the bitwidth of the switched-on value after promotions. We must
1362 // convert the integer case values to this width before comparison.
1363 bool HasDependentValue
1364 = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
1365 unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(T: CondType);
1366 bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
1367
1368 // Get the width and signedness that the condition might actually have, for
1369 // warning purposes.
1370 // FIXME: Grab an IntRange for the condition rather than using the unpromoted
1371 // type.
1372 unsigned CondWidthBeforePromotion
1373 = HasDependentValue ? 0 : Context.getIntWidth(T: CondTypeBeforePromotion);
1374 bool CondIsSignedBeforePromotion
1375 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
1376
1377 // Accumulate all of the case values in a vector so that we can sort them
1378 // and detect duplicates. This vector contains the APInt for the case after
1379 // it has been converted to the condition type.
1380 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
1381 CaseValsTy CaseVals;
1382
1383 // Keep track of any GNU case ranges we see. The APSInt is the low value.
1384 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
1385 CaseRangesTy CaseRanges;
1386
1387 DefaultStmt *TheDefaultStmt = nullptr;
1388
1389 bool CaseListIsErroneous = false;
1390
1391 // FIXME: We'd better diagnose missing or duplicate default labels even
1392 // in the dependent case. Because default labels themselves are never
1393 // dependent.
1394 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
1395 SC = SC->getNextSwitchCase()) {
1396
1397 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(Val: SC)) {
1398 if (TheDefaultStmt) {
1399 Diag(Loc: DS->getDefaultLoc(), DiagID: diag::err_multiple_default_labels_defined);
1400 Diag(Loc: TheDefaultStmt->getDefaultLoc(), DiagID: diag::note_duplicate_case_prev);
1401
1402 // FIXME: Remove the default statement from the switch block so that
1403 // we'll return a valid AST. This requires recursing down the AST and
1404 // finding it, not something we are set up to do right now. For now,
1405 // just lop the entire switch stmt out of the AST.
1406 CaseListIsErroneous = true;
1407 }
1408 TheDefaultStmt = DS;
1409
1410 } else {
1411 CaseStmt *CS = cast<CaseStmt>(Val: SC);
1412
1413 Expr *Lo = CS->getLHS();
1414
1415 if (Lo->isValueDependent()) {
1416 HasDependentValue = true;
1417 break;
1418 }
1419
1420 // We already verified that the expression has a constant value;
1421 // get that value (prior to conversions).
1422 const Expr *LoBeforePromotion = Lo;
1423 GetTypeBeforeIntegralPromotion(E&: LoBeforePromotion);
1424 llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1425
1426 // Check the unconverted value is within the range of possible values of
1427 // the switch expression.
1428 checkCaseValue(S&: *this, Loc: Lo->getBeginLoc(), Val: LoVal, UnpromotedWidth: CondWidthBeforePromotion,
1429 UnpromotedSign: CondIsSignedBeforePromotion);
1430
1431 // FIXME: This duplicates the check performed for warn_not_in_enum below.
1432 checkEnumTypesInSwitchStmt(S&: *this, Cond: CondExprBeforePromotion,
1433 Case: LoBeforePromotion);
1434
1435 // Convert the value to the same width/sign as the condition.
1436 AdjustAPSInt(Val&: LoVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1437
1438 // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
1439 if (CS->getRHS()) {
1440 if (CS->getRHS()->isValueDependent()) {
1441 HasDependentValue = true;
1442 break;
1443 }
1444 CaseRanges.push_back(x: std::make_pair(x&: LoVal, y&: CS));
1445 } else
1446 CaseVals.push_back(Elt: std::make_pair(x&: LoVal, y&: CS));
1447 }
1448 }
1449
1450 if (!HasDependentValue) {
1451 // If we don't have a default statement, check whether the
1452 // condition is constant.
1453 llvm::APSInt ConstantCondValue;
1454 bool HasConstantCond = false;
1455 if (!TheDefaultStmt) {
1456 Expr::EvalResult Result;
1457 HasConstantCond = CondExpr->EvaluateAsInt(Result, Ctx: Context,
1458 AllowSideEffects: Expr::SE_AllowSideEffects);
1459 if (Result.Val.isInt())
1460 ConstantCondValue = Result.Val.getInt();
1461 assert(!HasConstantCond ||
1462 (ConstantCondValue.getBitWidth() == CondWidth &&
1463 ConstantCondValue.isSigned() == CondIsSigned));
1464 Diag(Loc: SwitchLoc, DiagID: diag::warn_switch_default);
1465 }
1466 bool ShouldCheckConstantCond = HasConstantCond;
1467
1468 // Sort all the scalar case values so we can easily detect duplicates.
1469 llvm::stable_sort(Range&: CaseVals, C: CmpCaseVals);
1470
1471 if (!CaseVals.empty()) {
1472 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
1473 if (ShouldCheckConstantCond &&
1474 CaseVals[i].first == ConstantCondValue)
1475 ShouldCheckConstantCond = false;
1476
1477 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
1478 // If we have a duplicate, report it.
1479 // First, determine if either case value has a name
1480 StringRef PrevString, CurrString;
1481 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
1482 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
1483 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: PrevCase)) {
1484 PrevString = DeclRef->getDecl()->getName();
1485 }
1486 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: CurrCase)) {
1487 CurrString = DeclRef->getDecl()->getName();
1488 }
1489 SmallString<16> CaseValStr;
1490 CaseVals[i-1].first.toString(Str&: CaseValStr);
1491
1492 if (PrevString == CurrString)
1493 Diag(Loc: CaseVals[i].second->getLHS()->getBeginLoc(),
1494 DiagID: diag::err_duplicate_case)
1495 << (PrevString.empty() ? CaseValStr.str() : PrevString);
1496 else
1497 Diag(Loc: CaseVals[i].second->getLHS()->getBeginLoc(),
1498 DiagID: diag::err_duplicate_case_differing_expr)
1499 << (PrevString.empty() ? CaseValStr.str() : PrevString)
1500 << (CurrString.empty() ? CaseValStr.str() : CurrString)
1501 << CaseValStr;
1502
1503 Diag(Loc: CaseVals[i - 1].second->getLHS()->getBeginLoc(),
1504 DiagID: diag::note_duplicate_case_prev);
1505 // FIXME: We really want to remove the bogus case stmt from the
1506 // substmt, but we have no way to do this right now.
1507 CaseListIsErroneous = true;
1508 }
1509 }
1510 }
1511
1512 // Detect duplicate case ranges, which usually don't exist at all in
1513 // the first place.
1514 if (!CaseRanges.empty()) {
1515 // Sort all the case ranges by their low value so we can easily detect
1516 // overlaps between ranges.
1517 llvm::stable_sort(Range&: CaseRanges);
1518
1519 // Scan the ranges, computing the high values and removing empty ranges.
1520 std::vector<llvm::APSInt> HiVals;
1521 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1522 llvm::APSInt &LoVal = CaseRanges[i].first;
1523 CaseStmt *CR = CaseRanges[i].second;
1524 Expr *Hi = CR->getRHS();
1525
1526 const Expr *HiBeforePromotion = Hi;
1527 GetTypeBeforeIntegralPromotion(E&: HiBeforePromotion);
1528 llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1529
1530 // Check the unconverted value is within the range of possible values of
1531 // the switch expression.
1532 checkCaseValue(S&: *this, Loc: Hi->getBeginLoc(), Val: HiVal,
1533 UnpromotedWidth: CondWidthBeforePromotion, UnpromotedSign: CondIsSignedBeforePromotion);
1534
1535 // Convert the value to the same width/sign as the condition.
1536 AdjustAPSInt(Val&: HiVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1537
1538 // If the low value is bigger than the high value, the case is empty.
1539 if (LoVal > HiVal) {
1540 Diag(Loc: CR->getLHS()->getBeginLoc(), DiagID: diag::warn_case_empty_range)
1541 << SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
1542 CaseRanges.erase(position: CaseRanges.begin()+i);
1543 --i;
1544 --e;
1545 continue;
1546 }
1547
1548 if (ShouldCheckConstantCond &&
1549 LoVal <= ConstantCondValue &&
1550 ConstantCondValue <= HiVal)
1551 ShouldCheckConstantCond = false;
1552
1553 HiVals.push_back(x: HiVal);
1554 }
1555
1556 // Rescan the ranges, looking for overlap with singleton values and other
1557 // ranges. Since the range list is sorted, we only need to compare case
1558 // ranges with their neighbors.
1559 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1560 llvm::APSInt &CRLo = CaseRanges[i].first;
1561 llvm::APSInt &CRHi = HiVals[i];
1562 CaseStmt *CR = CaseRanges[i].second;
1563
1564 // Check to see whether the case range overlaps with any
1565 // singleton cases.
1566 CaseStmt *OverlapStmt = nullptr;
1567 llvm::APSInt OverlapVal(32);
1568
1569 // Find the smallest value >= the lower bound. If I is in the
1570 // case range, then we have overlap.
1571 CaseValsTy::iterator I =
1572 llvm::lower_bound(Range&: CaseVals, Value&: CRLo, C: CaseCompareFunctor());
1573 if (I != CaseVals.end() && I->first < CRHi) {
1574 OverlapVal = I->first; // Found overlap with scalar.
1575 OverlapStmt = I->second;
1576 }
1577
1578 // Find the smallest value bigger than the upper bound.
1579 I = std::upper_bound(first: I, last: CaseVals.end(), val: CRHi, comp: CaseCompareFunctor());
1580 if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1581 OverlapVal = (I-1)->first; // Found overlap with scalar.
1582 OverlapStmt = (I-1)->second;
1583 }
1584
1585 // Check to see if this case stmt overlaps with the subsequent
1586 // case range.
1587 if (i && CRLo <= HiVals[i-1]) {
1588 OverlapVal = HiVals[i-1]; // Found overlap with range.
1589 OverlapStmt = CaseRanges[i-1].second;
1590 }
1591
1592 if (OverlapStmt) {
1593 // If we have a duplicate, report it.
1594 Diag(Loc: CR->getLHS()->getBeginLoc(), DiagID: diag::err_duplicate_case)
1595 << toString(I: OverlapVal, Radix: 10);
1596 Diag(Loc: OverlapStmt->getLHS()->getBeginLoc(),
1597 DiagID: diag::note_duplicate_case_prev);
1598 // FIXME: We really want to remove the bogus case stmt from the
1599 // substmt, but we have no way to do this right now.
1600 CaseListIsErroneous = true;
1601 }
1602 }
1603 }
1604
1605 // Complain if we have a constant condition and we didn't find a match.
1606 if (!CaseListIsErroneous && !CaseListIsIncomplete &&
1607 ShouldCheckConstantCond) {
1608 // TODO: it would be nice if we printed enums as enums, chars as
1609 // chars, etc.
1610 Diag(Loc: CondExpr->getExprLoc(), DiagID: diag::warn_missing_case_for_condition)
1611 << toString(I: ConstantCondValue, Radix: 10)
1612 << CondExpr->getSourceRange();
1613 }
1614
1615 // Check to see if switch is over an Enum and handles all of its
1616 // values. We only issue a warning if there is not 'default:', but
1617 // we still do the analysis to preserve this information in the AST
1618 // (which can be used by flow-based analyes).
1619 //
1620 // If switch has default case, then ignore it.
1621 if (!CaseListIsErroneous && !CaseListIsIncomplete && !HasConstantCond &&
1622 CondTypeBeforePromotion->isEnumeralType()) {
1623 const auto *ED = CondTypeBeforePromotion->castAsEnumDecl();
1624 if (!ED->isCompleteDefinition() || ED->enumerators().empty())
1625 goto enum_out;
1626
1627 EnumValsTy EnumVals;
1628
1629 // Gather all enum values, set their type and sort them,
1630 // allowing easier comparison with CaseVals.
1631 for (auto *EDI : ED->enumerators()) {
1632 llvm::APSInt Val = EDI->getInitVal();
1633 AdjustAPSInt(Val, BitWidth: CondWidth, IsSigned: CondIsSigned);
1634 EnumVals.push_back(Elt: std::make_pair(x&: Val, y&: EDI));
1635 }
1636 llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1637 auto EI = EnumVals.begin(), EIEnd = llvm::unique(R&: EnumVals, P: EqEnumVals);
1638
1639 // See which case values aren't in enum.
1640 for (CaseValsTy::const_iterator CI = CaseVals.begin();
1641 CI != CaseVals.end(); CI++) {
1642 Expr *CaseExpr = CI->second->getLHS();
1643 if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1644 Val: CI->first))
1645 Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1646 << CondTypeBeforePromotion;
1647 }
1648
1649 // See which of case ranges aren't in enum
1650 EI = EnumVals.begin();
1651 for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1652 RI != CaseRanges.end(); RI++) {
1653 Expr *CaseExpr = RI->second->getLHS();
1654 if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1655 Val: RI->first))
1656 Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1657 << CondTypeBeforePromotion;
1658
1659 llvm::APSInt Hi =
1660 RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1661 AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1662
1663 CaseExpr = RI->second->getRHS();
1664 if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1665 Val: Hi))
1666 Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1667 << CondTypeBeforePromotion;
1668 }
1669
1670 // Check which enum vals aren't in switch
1671 auto CI = CaseVals.begin();
1672 auto RI = CaseRanges.begin();
1673 bool hasCasesNotInSwitch = false;
1674
1675 SmallVector<DeclarationName,8> UnhandledNames;
1676
1677 for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
1678 // Don't warn about omitted unavailable EnumConstantDecls.
1679 switch (EI->second->getAvailability()) {
1680 case AR_Deprecated:
1681 // Deprecated enumerators need to be handled: they may be deprecated,
1682 // but can still occur.
1683 break;
1684
1685 case AR_Unavailable:
1686 // Omitting an unavailable enumerator is ok; it should never occur.
1687 continue;
1688
1689 case AR_NotYetIntroduced:
1690 // Partially available enum constants should be present. Note that we
1691 // suppress -Wunguarded-availability diagnostics for such uses.
1692 case AR_Available:
1693 break;
1694 }
1695
1696 if (EI->second->hasAttr<UnusedAttr>())
1697 continue;
1698
1699 // Drop unneeded case values
1700 while (CI != CaseVals.end() && CI->first < EI->first)
1701 CI++;
1702
1703 if (CI != CaseVals.end() && CI->first == EI->first)
1704 continue;
1705
1706 // Drop unneeded case ranges
1707 for (; RI != CaseRanges.end(); RI++) {
1708 llvm::APSInt Hi =
1709 RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1710 AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1711 if (EI->first <= Hi)
1712 break;
1713 }
1714
1715 if (RI == CaseRanges.end() || EI->first < RI->first) {
1716 hasCasesNotInSwitch = true;
1717 UnhandledNames.push_back(Elt: EI->second->getDeclName());
1718 }
1719 }
1720
1721 if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1722 Diag(Loc: TheDefaultStmt->getDefaultLoc(), DiagID: diag::warn_unreachable_default);
1723
1724 // Produce a nice diagnostic if multiple values aren't handled.
1725 if (!UnhandledNames.empty()) {
1726 auto DB = Diag(Loc: CondExpr->getExprLoc(), DiagID: TheDefaultStmt
1727 ? diag::warn_def_missing_case
1728 : diag::warn_missing_case)
1729 << CondExpr->getSourceRange() << (int)UnhandledNames.size();
1730
1731 for (size_t I = 0, E = std::min(a: UnhandledNames.size(), b: (size_t)3);
1732 I != E; ++I)
1733 DB << UnhandledNames[I];
1734 }
1735
1736 if (!hasCasesNotInSwitch)
1737 SS->setAllEnumCasesCovered();
1738 }
1739 enum_out:;
1740 }
1741
1742 if (BodyStmt)
1743 DiagnoseEmptyStmtBody(StmtLoc: CondExpr->getEndLoc(), Body: BodyStmt,
1744 DiagID: diag::warn_empty_switch_body);
1745
1746 // FIXME: If the case list was broken is some way, we don't have a good system
1747 // to patch it up. Instead, just return the whole substmt as broken.
1748 if (CaseListIsErroneous)
1749 return StmtError();
1750
1751 return SS;
1752}
1753
1754void
1755Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1756 Expr *SrcExpr) {
1757
1758 if (!DstType->isEnumeralType())
1759 return;
1760
1761 if (!SrcType->isIntegerType() ||
1762 Context.hasSameUnqualifiedType(T1: SrcType, T2: DstType))
1763 return;
1764
1765 if (SrcExpr->isTypeDependent() || SrcExpr->isValueDependent())
1766 return;
1767
1768 const auto *ED = DstType->castAsEnumDecl();
1769 if (!ED->isClosed())
1770 return;
1771
1772 if (Diags.isIgnored(DiagID: diag::warn_not_in_enum_assignment, Loc: SrcExpr->getExprLoc()))
1773 return;
1774
1775 std::optional<llvm::APSInt> RHSVal = SrcExpr->getIntegerConstantExpr(Ctx: Context);
1776 if (!RHSVal)
1777 return;
1778
1779 // Get the bitwidth of the enum value before promotions.
1780 unsigned DstWidth = Context.getIntWidth(T: DstType);
1781 bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1782 AdjustAPSInt(Val&: *RHSVal, BitWidth: DstWidth, IsSigned: DstIsSigned);
1783
1784 if (ED->hasAttr<FlagEnumAttr>()) {
1785 if (!IsValueInFlagEnum(ED, Val: *RHSVal, /*AllowMask=*/true))
1786 Diag(Loc: SrcExpr->getExprLoc(), DiagID: diag::warn_not_in_enum_assignment)
1787 << DstType.getUnqualifiedType();
1788 return;
1789 }
1790
1791 const EnumDecl *Key = ED->getCanonicalDecl();
1792 auto [It, Inserted] = AssignEnumCache.try_emplace(Key);
1793 auto &Values = It->second;
1794
1795 if (Inserted) {
1796 Values.reserve(N: std::distance(first: ED->enumerator_begin(), last: ED->enumerator_end()));
1797
1798 for (auto *EC : ED->enumerators()) {
1799 Values.push_back(Elt: EC->getInitVal());
1800 AdjustAPSInt(Val&: Values.back(), BitWidth: DstWidth, IsSigned: DstIsSigned);
1801 }
1802
1803 if (Values.empty())
1804 return;
1805
1806 llvm::sort(C&: Values);
1807 Values.erase(CS: llvm::unique(R&: Values), CE: Values.end());
1808 }
1809
1810 if (llvm::binary_search(Range&: Values, Value&: *RHSVal))
1811 return;
1812
1813 Diag(Loc: SrcExpr->getExprLoc(), DiagID: diag::warn_not_in_enum_assignment)
1814 << DstType.getUnqualifiedType();
1815}
1816
1817StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
1818 SourceLocation LParenLoc, ConditionResult Cond,
1819 SourceLocation RParenLoc, Stmt *Body) {
1820 if (Cond.isInvalid())
1821 return StmtError();
1822
1823 auto CondVal = Cond.get();
1824
1825 if (CondVal.second &&
1826 !Diags.isIgnored(DiagID: diag::warn_comma_operator, Loc: CondVal.second->getExprLoc()))
1827 CommaVisitor(*this).Visit(S: CondVal.second);
1828
1829 // OpenACC3.3 2.14.4:
1830 // The update directive is executable. It must not appear in place of the
1831 // statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1832 // C++.
1833 if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1834 Diag(Loc: Body->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*while*/ 1;
1835 Body = new (Context) NullStmt(Body->getBeginLoc());
1836 }
1837
1838 if (isa<NullStmt>(Val: Body))
1839 getCurCompoundScope().setHasEmptyLoopBodies();
1840
1841 return WhileStmt::Create(Ctx: Context, Var: CondVal.first, Cond: CondVal.second, Body,
1842 WL: WhileLoc, LParenLoc, RParenLoc);
1843}
1844
1845StmtResult
1846Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1847 SourceLocation WhileLoc, SourceLocation CondLParen,
1848 Expr *Cond, SourceLocation CondRParen) {
1849 assert(Cond && "ActOnDoStmt(): missing expression");
1850
1851 ExprResult CondResult = CheckBooleanCondition(Loc: DoLoc, E: Cond);
1852 if (CondResult.isInvalid())
1853 return StmtError();
1854 Cond = CondResult.get();
1855
1856 CondResult = ActOnFinishFullExpr(Expr: Cond, CC: DoLoc, /*DiscardedValue*/ false);
1857 if (CondResult.isInvalid())
1858 return StmtError();
1859 Cond = CondResult.get();
1860
1861 // OpenACC3.3 2.14.4:
1862 // The update directive is executable. It must not appear in place of the
1863 // statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1864 // C++.
1865 if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1866 Diag(Loc: Body->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*do*/ 2;
1867 Body = new (Context) NullStmt(Body->getBeginLoc());
1868 }
1869
1870 return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1871}
1872
1873namespace {
1874 // Use SetVector since the diagnostic cares about the ordering of the Decl's.
1875 using DeclSetVector = llvm::SmallSetVector<VarDecl *, 8>;
1876
1877 // This visitor will traverse a conditional statement and store all
1878 // the evaluated decls into a vector. Simple is set to true if none
1879 // of the excluded constructs are used.
1880 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1881 DeclSetVector &Decls;
1882 SmallVectorImpl<SourceRange> &Ranges;
1883 bool Simple;
1884 public:
1885 typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1886
1887 DeclExtractor(Sema &S, DeclSetVector &Decls,
1888 SmallVectorImpl<SourceRange> &Ranges) :
1889 Inherited(S.Context),
1890 Decls(Decls),
1891 Ranges(Ranges),
1892 Simple(true) {}
1893
1894 bool isSimple() { return Simple; }
1895
1896 // Replaces the method in EvaluatedExprVisitor.
1897 void VisitMemberExpr(MemberExpr* E) {
1898 Simple = false;
1899 }
1900
1901 // Any Stmt not explicitly listed will cause the condition to be marked
1902 // complex.
1903 void VisitStmt(Stmt *S) { Simple = false; }
1904
1905 void VisitBinaryOperator(BinaryOperator *E) {
1906 Visit(S: E->getLHS());
1907 Visit(S: E->getRHS());
1908 }
1909
1910 void VisitCastExpr(CastExpr *E) {
1911 Visit(S: E->getSubExpr());
1912 }
1913
1914 void VisitUnaryOperator(UnaryOperator *E) {
1915 // Skip checking conditionals with derefernces.
1916 if (E->getOpcode() == UO_Deref)
1917 Simple = false;
1918 else
1919 Visit(S: E->getSubExpr());
1920 }
1921
1922 void VisitConditionalOperator(ConditionalOperator *E) {
1923 Visit(S: E->getCond());
1924 Visit(S: E->getTrueExpr());
1925 Visit(S: E->getFalseExpr());
1926 }
1927
1928 void VisitParenExpr(ParenExpr *E) {
1929 Visit(S: E->getSubExpr());
1930 }
1931
1932 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1933 Visit(S: E->getOpaqueValue()->getSourceExpr());
1934 Visit(S: E->getFalseExpr());
1935 }
1936
1937 void VisitIntegerLiteral(IntegerLiteral *E) { }
1938 void VisitFloatingLiteral(FloatingLiteral *E) { }
1939 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1940 void VisitCharacterLiteral(CharacterLiteral *E) { }
1941 void VisitGNUNullExpr(GNUNullExpr *E) { }
1942 void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1943
1944 void VisitDeclRefExpr(DeclRefExpr *E) {
1945 VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl());
1946 if (!VD) {
1947 // Don't allow unhandled Decl types.
1948 Simple = false;
1949 return;
1950 }
1951
1952 Ranges.push_back(Elt: E->getSourceRange());
1953
1954 Decls.insert(X: VD);
1955 }
1956
1957 }; // end class DeclExtractor
1958
1959 // DeclMatcher checks to see if the decls are used in a non-evaluated
1960 // context.
1961 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1962 DeclSetVector &Decls;
1963 bool FoundDecl;
1964
1965 public:
1966 typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1967
1968 DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1969 Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1970 if (!Statement) return;
1971
1972 Visit(S: Statement);
1973 }
1974
1975 void VisitReturnStmt(ReturnStmt *S) {
1976 FoundDecl = true;
1977 }
1978
1979 void VisitBreakStmt(BreakStmt *S) {
1980 FoundDecl = true;
1981 }
1982
1983 void VisitGotoStmt(GotoStmt *S) {
1984 FoundDecl = true;
1985 }
1986
1987 void VisitCastExpr(CastExpr *E) {
1988 if (E->getCastKind() == CK_LValueToRValue)
1989 CheckLValueToRValueCast(E: E->getSubExpr());
1990 else
1991 Visit(S: E->getSubExpr());
1992 }
1993
1994 void CheckLValueToRValueCast(Expr *E) {
1995 E = E->IgnoreParenImpCasts();
1996
1997 if (isa<DeclRefExpr>(Val: E)) {
1998 return;
1999 }
2000
2001 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(Val: E)) {
2002 Visit(S: CO->getCond());
2003 CheckLValueToRValueCast(E: CO->getTrueExpr());
2004 CheckLValueToRValueCast(E: CO->getFalseExpr());
2005 return;
2006 }
2007
2008 if (BinaryConditionalOperator *BCO =
2009 dyn_cast<BinaryConditionalOperator>(Val: E)) {
2010 CheckLValueToRValueCast(E: BCO->getOpaqueValue()->getSourceExpr());
2011 CheckLValueToRValueCast(E: BCO->getFalseExpr());
2012 return;
2013 }
2014
2015 Visit(S: E);
2016 }
2017
2018 void VisitDeclRefExpr(DeclRefExpr *E) {
2019 if (const auto *VD = dyn_cast<VarDecl>(Val: E->getDecl())) {
2020 if (Decls.count(key: VD))
2021 FoundDecl = true;
2022 } else if (const auto *MD = dyn_cast<CXXMethodDecl>(Val: E->getDecl());
2023 MD && isLambdaCallOperator(MD)) {
2024 // FIXME: This has limitations handling updates to the loop control
2025 // variable that occur indirectly inside a lambda called from the loop
2026 // body. For example:
2027 //
2028 // int a = 0;
2029 // int *c = &a;
2030 // auto incr_c = [c]() { ++*c; };
2031 // for (a = 10; a <= 20; incr_c())
2032 // foo(a);
2033 for (const auto &Capture : MD->getParent()->captures()) {
2034 if (!Capture.capturesVariable())
2035 continue;
2036
2037 LambdaCaptureKind CK = Capture.getCaptureKind();
2038 if (CK != LCK_ByRef)
2039 continue;
2040
2041 const auto *VD = dyn_cast<VarDecl>(Val: Capture.getCapturedVar());
2042 if (VD && Decls.count(key: VD))
2043 FoundDecl = true;
2044 }
2045 }
2046 }
2047
2048 void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
2049 // Only need to visit the semantics for POE.
2050 // SyntaticForm doesn't really use the Decal.
2051 for (auto *S : POE->semantics()) {
2052 if (auto *OVE = dyn_cast<OpaqueValueExpr>(Val: S))
2053 // Look past the OVE into the expression it binds.
2054 Visit(S: OVE->getSourceExpr());
2055 else
2056 Visit(S);
2057 }
2058 }
2059
2060 bool FoundDeclInUse() { return FoundDecl; }
2061
2062 }; // end class DeclMatcher
2063
2064 void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
2065 Expr *Third, Stmt *Body) {
2066 // Condition is empty
2067 if (!Second) return;
2068
2069 if (S.Diags.isIgnored(DiagID: diag::warn_variables_not_in_loop_body,
2070 Loc: Second->getBeginLoc()))
2071 return;
2072
2073 PartialDiagnostic PDiag = S.PDiag(DiagID: diag::warn_variables_not_in_loop_body);
2074 DeclSetVector Decls;
2075 SmallVector<SourceRange, 10> Ranges;
2076 DeclExtractor DE(S, Decls, Ranges);
2077 DE.Visit(S: Second);
2078
2079 // Don't analyze complex conditionals.
2080 if (!DE.isSimple()) return;
2081
2082 // No decls found.
2083 if (Decls.size() == 0) return;
2084
2085 // Don't warn on volatile, static, or global variables.
2086 for (auto *VD : Decls)
2087 if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
2088 return;
2089
2090 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
2091 DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
2092 DeclMatcher(S, Decls, Body).FoundDeclInUse())
2093 return;
2094
2095 // Load decl names into diagnostic.
2096 if (Decls.size() > 4) {
2097 PDiag << 0;
2098 } else {
2099 PDiag << (unsigned)Decls.size();
2100 for (auto *VD : Decls)
2101 PDiag << VD->getDeclName();
2102 }
2103
2104 for (auto Range : Ranges)
2105 PDiag << Range;
2106
2107 S.Diag(Loc: Ranges.begin()->getBegin(), PD: PDiag);
2108 }
2109
2110 // If Statement is an incemement or decrement, return true and sets the
2111 // variables Increment and DRE.
2112 bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
2113 DeclRefExpr *&DRE) {
2114 if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: Statement))
2115 if (!Cleanups->cleanupsHaveSideEffects())
2116 Statement = Cleanups->getSubExpr();
2117
2118 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Statement)) {
2119 switch (UO->getOpcode()) {
2120 default: return false;
2121 case UO_PostInc:
2122 case UO_PreInc:
2123 Increment = true;
2124 break;
2125 case UO_PostDec:
2126 case UO_PreDec:
2127 Increment = false;
2128 break;
2129 }
2130 DRE = dyn_cast<DeclRefExpr>(Val: UO->getSubExpr());
2131 return DRE;
2132 }
2133
2134 if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Val: Statement)) {
2135 FunctionDecl *FD = Call->getDirectCallee();
2136 if (!FD || !FD->isOverloadedOperator()) return false;
2137 switch (FD->getOverloadedOperator()) {
2138 default: return false;
2139 case OO_PlusPlus:
2140 Increment = true;
2141 break;
2142 case OO_MinusMinus:
2143 Increment = false;
2144 break;
2145 }
2146 DRE = dyn_cast<DeclRefExpr>(Val: Call->getArg(Arg: 0));
2147 return DRE;
2148 }
2149
2150 return false;
2151 }
2152
2153 // A visitor to determine if a continue or break statement is a
2154 // subexpression.
2155 class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
2156 SourceLocation BreakLoc;
2157 SourceLocation ContinueLoc;
2158 bool InSwitch = false;
2159
2160 public:
2161 BreakContinueFinder(Sema &S, const Stmt* Body) :
2162 Inherited(S.Context) {
2163 Visit(S: Body);
2164 }
2165
2166 typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
2167
2168 void VisitContinueStmt(const ContinueStmt* E) {
2169 ContinueLoc = E->getKwLoc();
2170 }
2171
2172 void VisitBreakStmt(const BreakStmt* E) {
2173 if (!InSwitch)
2174 BreakLoc = E->getKwLoc();
2175 }
2176
2177 void VisitSwitchStmt(const SwitchStmt* S) {
2178 if (const Stmt *Init = S->getInit())
2179 Visit(S: Init);
2180 if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
2181 Visit(S: CondVar);
2182 if (const Stmt *Cond = S->getCond())
2183 Visit(S: Cond);
2184
2185 // Don't return break statements from the body of a switch.
2186 InSwitch = true;
2187 if (const Stmt *Body = S->getBody())
2188 Visit(S: Body);
2189 InSwitch = false;
2190 }
2191
2192 void VisitForStmt(const ForStmt *S) {
2193 // Only visit the init statement of a for loop; the body
2194 // has a different break/continue scope.
2195 if (const Stmt *Init = S->getInit())
2196 Visit(S: Init);
2197 }
2198
2199 void VisitWhileStmt(const WhileStmt *) {
2200 // Do nothing; the children of a while loop have a different
2201 // break/continue scope.
2202 }
2203
2204 void VisitDoStmt(const DoStmt *) {
2205 // Do nothing; the children of a while loop have a different
2206 // break/continue scope.
2207 }
2208
2209 void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
2210 // Only visit the initialization of a for loop; the body
2211 // has a different break/continue scope.
2212 if (const Stmt *Init = S->getInit())
2213 Visit(S: Init);
2214 if (const Stmt *Range = S->getRangeStmt())
2215 Visit(S: Range);
2216 if (const Stmt *Begin = S->getBeginStmt())
2217 Visit(S: Begin);
2218 if (const Stmt *End = S->getEndStmt())
2219 Visit(S: End);
2220 }
2221
2222 void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
2223 // Only visit the initialization of a for loop; the body
2224 // has a different break/continue scope.
2225 if (const Stmt *Element = S->getElement())
2226 Visit(S: Element);
2227 if (const Stmt *Collection = S->getCollection())
2228 Visit(S: Collection);
2229 }
2230
2231 bool ContinueFound() { return ContinueLoc.isValid(); }
2232 bool BreakFound() { return BreakLoc.isValid(); }
2233 SourceLocation GetContinueLoc() { return ContinueLoc; }
2234 SourceLocation GetBreakLoc() { return BreakLoc; }
2235
2236 }; // end class BreakContinueFinder
2237
2238 // Emit a warning when a loop increment/decrement appears twice per loop
2239 // iteration. The conditions which trigger this warning are:
2240 // 1) The last statement in the loop body and the third expression in the
2241 // for loop are both increment or both decrement of the same variable
2242 // 2) No continue statements in the loop body.
2243 void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
2244 // Return when there is nothing to check.
2245 if (!Body || !Third) return;
2246
2247 // Get the last statement from the loop body.
2248 CompoundStmt *CS = dyn_cast<CompoundStmt>(Val: Body);
2249 if (!CS || CS->body_empty()) return;
2250 Stmt *LastStmt = CS->body_back();
2251 if (!LastStmt) return;
2252
2253 if (S.Diags.isIgnored(DiagID: diag::warn_redundant_loop_iteration,
2254 Loc: Third->getBeginLoc()))
2255 return;
2256
2257 bool LoopIncrement, LastIncrement;
2258 DeclRefExpr *LoopDRE, *LastDRE;
2259
2260 if (!ProcessIterationStmt(S, Statement: Third, Increment&: LoopIncrement, DRE&: LoopDRE)) return;
2261 if (!ProcessIterationStmt(S, Statement: LastStmt, Increment&: LastIncrement, DRE&: LastDRE)) return;
2262
2263 // Check that the two statements are both increments or both decrements
2264 // on the same variable.
2265 if (LoopIncrement != LastIncrement ||
2266 LoopDRE->getDecl() != LastDRE->getDecl()) return;
2267
2268 if (BreakContinueFinder(S, Body).ContinueFound()) return;
2269
2270 S.Diag(Loc: LastDRE->getLocation(), DiagID: diag::warn_redundant_loop_iteration)
2271 << LastDRE->getDecl() << LastIncrement;
2272 S.Diag(Loc: LoopDRE->getLocation(), DiagID: diag::note_loop_iteration_here)
2273 << LoopIncrement;
2274 }
2275
2276} // end namespace
2277
2278StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
2279 Stmt *First, ConditionResult Second,
2280 FullExprArg third, SourceLocation RParenLoc,
2281 Stmt *Body) {
2282 if (Second.isInvalid())
2283 return StmtError();
2284
2285 if (!getLangOpts().CPlusPlus) {
2286 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(Val: First)) {
2287 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
2288 // declare identifiers for objects having storage class 'auto' or
2289 // 'register'.
2290 const Decl *NonVarSeen = nullptr;
2291 bool VarDeclSeen = false;
2292 for (auto *DI : DS->decls()) {
2293 if (VarDecl *VD = dyn_cast<VarDecl>(Val: DI)) {
2294 VarDeclSeen = true;
2295 if (VD->isLocalVarDecl() && !VD->hasLocalStorage())
2296 DiagCompat(Loc: DI->getLocation(),
2297 CompatDiagId: diag_compat::non_local_variable_decl_in_for);
2298 } else if (!NonVarSeen) {
2299 // Keep track of the first non-variable declaration we saw so that
2300 // we can diagnose if we don't see any variable declarations. This
2301 // covers a case like declaring a typedef, function, or structure
2302 // type rather than a variable.
2303 //
2304 // Note, _Static_assert is acceptable because it does not declare an
2305 // identifier at all, so "for object having" does not apply.
2306 if (!isa<StaticAssertDecl>(Val: DI))
2307 NonVarSeen = DI;
2308 }
2309 }
2310 // Diagnose if we saw a non-variable declaration but no variable
2311 // declarations.
2312 if (NonVarSeen && !VarDeclSeen)
2313 DiagCompat(Loc: NonVarSeen->getLocation(),
2314 CompatDiagId: diag_compat::non_variable_decl_in_for);
2315 }
2316 }
2317
2318 if (!Second.get().first)
2319 CheckForLoopConditionalStatement(S&: *this, Second: Second.get().second, Third: third.get(),
2320 Body);
2321 CheckForRedundantIteration(S&: *this, Third: third.get(), Body);
2322
2323 if (Second.get().second &&
2324 !Diags.isIgnored(DiagID: diag::warn_comma_operator,
2325 Loc: Second.get().second->getExprLoc()))
2326 CommaVisitor(*this).Visit(S: Second.get().second);
2327
2328 Expr *Third = third.release().getAs<Expr>();
2329 if (isa<NullStmt>(Val: Body))
2330 getCurCompoundScope().setHasEmptyLoopBodies();
2331
2332 return new (Context)
2333 ForStmt(Context, First, Second.get().second, Second.get().first, Third,
2334 Body, ForLoc, LParenLoc, RParenLoc);
2335}
2336
2337StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
2338 // Reduce placeholder expressions here. Note that this rejects the
2339 // use of pseudo-object l-values in this position.
2340 ExprResult result = CheckPlaceholderExpr(E);
2341 if (result.isInvalid()) return StmtError();
2342 E = result.get();
2343
2344 ExprResult FullExpr = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
2345 if (FullExpr.isInvalid())
2346 return StmtError();
2347 return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2348}
2349
2350/// Finish building a variable declaration for a for-range statement.
2351/// \return true if an error occurs.
2352static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
2353 SourceLocation Loc, int DiagID) {
2354 if (Decl->getType()->isUndeducedType()) {
2355 ExprResult Res = Init;
2356 if (!Res.isUsable()) {
2357 Decl->setInvalidDecl();
2358 return true;
2359 }
2360 Init = Res.get();
2361 }
2362
2363 // Deduce the type for the iterator variable now rather than leaving it to
2364 // AddInitializerToDecl, so we can produce a more suitable diagnostic.
2365 QualType InitType;
2366 if (!isa<InitListExpr>(Val: Init) && Init->getType()->isVoidType()) {
2367 SemaRef.Diag(Loc, DiagID) << Init->getType();
2368 } else {
2369 TemplateDeductionInfo Info(Init->getExprLoc());
2370 TemplateDeductionResult Result = SemaRef.DeduceAutoType(
2371 AutoTypeLoc: Decl->getTypeSourceInfo()->getTypeLoc(), Initializer: Init, Result&: InitType, Info);
2372 if (Result != TemplateDeductionResult::Success &&
2373 Result != TemplateDeductionResult::AlreadyDiagnosed)
2374 SemaRef.Diag(Loc, DiagID) << Init->getType();
2375 }
2376
2377 if (InitType.isNull()) {
2378 Decl->setInvalidDecl();
2379 return true;
2380 }
2381 Decl->setType(InitType);
2382
2383 // In ARC, infer lifetime.
2384 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
2385 // we're doing the equivalent of fast iteration.
2386 if (SemaRef.getLangOpts().ObjCAutoRefCount &&
2387 SemaRef.ObjC().inferObjCARCLifetime(decl: Decl))
2388 Decl->setInvalidDecl();
2389
2390 SemaRef.AddInitializerToDecl(dcl: Decl, init: Init, /*DirectInit=*/false);
2391 SemaRef.FinalizeDeclaration(D: Decl);
2392 SemaRef.CurContext->addHiddenDecl(D: Decl);
2393 return false;
2394}
2395
2396namespace {
2397// An enum to represent whether something is dealing with a call to begin()
2398// or a call to end() in a range-based for loop.
2399enum BeginEndFunction {
2400 BEF_begin,
2401 BEF_end
2402};
2403
2404/// Produce a note indicating which begin/end function was implicitly called
2405/// by a C++11 for-range statement. This is often not obvious from the code,
2406/// nor from the diagnostics produced when analysing the implicit expressions
2407/// required in a for-range statement.
2408void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2409 BeginEndFunction BEF) {
2410 CallExpr *CE = dyn_cast<CallExpr>(Val: E);
2411 if (!CE)
2412 return;
2413 FunctionDecl *D = dyn_cast<FunctionDecl>(Val: CE->getCalleeDecl());
2414 if (!D)
2415 return;
2416 SourceLocation Loc = D->getLocation();
2417
2418 std::string Description;
2419 bool IsTemplate = false;
2420 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2421 Description = SemaRef.getTemplateArgumentBindingsText(
2422 Params: FunTmpl->getTemplateParameters(), Args: *D->getTemplateSpecializationArgs());
2423 IsTemplate = true;
2424 }
2425
2426 SemaRef.Diag(Loc, DiagID: diag::note_for_range_begin_end)
2427 << BEF << IsTemplate << Description << E->getType();
2428}
2429} // namespace
2430
2431/// Build a variable declaration for a for-range statement.
2432VarDecl *Sema::BuildForRangeVarDecl(SourceLocation Loc, QualType Type,
2433 IdentifierInfo *II, bool IsConstexpr) {
2434 // Making the variable constexpr doesn't automatically add 'const' to the
2435 // type, so do that now.
2436 if (IsConstexpr && !Type->isReferenceType())
2437 Type = Type.withConst();
2438
2439 DeclContext *DC = CurContext;
2440 TypeSourceInfo *TInfo = Context.getTrivialTypeSourceInfo(T: Type, Loc);
2441 VarDecl *Decl =
2442 VarDecl::Create(C&: Context, DC, StartLoc: Loc, IdLoc: Loc, Id: II, T: Type, TInfo, S: SC_None);
2443 Decl->setImplicit();
2444 Decl->setCXXForRangeImplicitVar(true);
2445 if (IsConstexpr)
2446 // CWG3044 changed this from 'static constexpr' to 'constexpr'.
2447 Decl->setConstexpr(true);
2448 return Decl;
2449}
2450
2451static bool ObjCEnumerationCollection(Expr *Collection) {
2452 return !Collection->isTypeDependent()
2453 && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2454}
2455
2456StmtResult Sema::BuildCXXForRangeRangeVar(Scope *S, Expr *Range, QualType Type,
2457 bool IsConstexpr) {
2458
2459 // Divide by 2, since the variables are in the inner scope (loop body).
2460 const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2461 IdentifierInfo *Name =
2462 PP.getIdentifierInfo(Name: std::string("__range") + DepthStr);
2463 SourceLocation RangeLoc = Range->getBeginLoc();
2464 VarDecl *RangeVar = BuildForRangeVarDecl(Loc: RangeLoc, Type, II: Name, IsConstexpr);
2465 if (FinishForRangeVarDecl(SemaRef&: *this, Decl: RangeVar, Init: Range, Loc: RangeLoc,
2466 DiagID: diag::err_for_range_deduction_failure))
2467
2468 return StmtError();
2469
2470 // Claim the type doesn't contain auto: we've already done the checking.
2471 DeclGroupPtrTy RangeGroup =
2472 BuildDeclaratorGroup(Group: MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2473 return ActOnDeclStmt(dg: RangeGroup, StartLoc: RangeLoc, EndLoc: RangeLoc);
2474}
2475
2476StmtResult Sema::ActOnCXXForRangeStmt(
2477 Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2478 Stmt *First, SourceLocation ColonLoc, Expr *Range, SourceLocation RParenLoc,
2479 BuildForRangeKind Kind,
2480 ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2481 // FIXME: recover in order to allow the body to be parsed.
2482 if (!First)
2483 return StmtError();
2484
2485 if (Range && ObjCEnumerationCollection(Collection: Range)) {
2486 // FIXME: Support init-statements in Objective-C++20 ranged for statement.
2487 if (InitStmt)
2488 return Diag(Loc: InitStmt->getBeginLoc(), DiagID: diag::err_objc_for_range_init_stmt)
2489 << InitStmt->getSourceRange();
2490 return ObjC().ActOnObjCForCollectionStmt(ForColLoc: ForLoc, First, collection: Range, RParenLoc);
2491 }
2492
2493 DeclStmt *DS = dyn_cast<DeclStmt>(Val: First);
2494 assert(DS && "first part of for range not a decl stmt");
2495
2496 if (!DS->isSingleDecl()) {
2497 Diag(Loc: DS->getBeginLoc(), DiagID: diag::err_type_defined_in_for_range);
2498 return StmtError();
2499 }
2500
2501 // This function is responsible for attaching an initializer to LoopVar. We
2502 // must call ActOnInitializerError if we fail to do so.
2503 Decl *LoopVar = DS->getSingleDecl();
2504 if (LoopVar->isInvalidDecl() || !Range ||
2505 DiagnoseUnexpandedParameterPack(E: Range, UPPC: UPPC_Expression)) {
2506 ActOnInitializerError(Dcl: LoopVar);
2507 return StmtError();
2508 }
2509
2510 // Build the coroutine state immediately and not later during template
2511 // instantiation
2512 if (!CoawaitLoc.isInvalid()) {
2513 if (!ActOnCoroutineBodyStart(S, KwLoc: CoawaitLoc, Keyword: "co_await")) {
2514 ActOnInitializerError(Dcl: LoopVar);
2515 return StmtError();
2516 }
2517 }
2518
2519 // Build auto && __range = range-init
2520 auto RangeDecl =
2521 BuildCXXForRangeRangeVar(S, Range, Type: Context.getAutoRRefDeductType());
2522 if (RangeDecl.isInvalid()) {
2523 ActOnInitializerError(Dcl: LoopVar);
2524 return StmtError();
2525 }
2526
2527 StmtResult R = BuildCXXForRangeStmt(
2528 ForLoc, CoawaitLoc, InitStmt, ColonLoc, RangeDecl: RangeDecl.get(),
2529 /*BeginStmt=*/Begin: nullptr, /*EndStmt=*/End: nullptr,
2530 /*Cond=*/nullptr, /*Inc=*/nullptr, LoopVarDecl: DS, RParenLoc, Kind,
2531 LifetimeExtendTemps);
2532 if (R.isInvalid()) {
2533 ActOnInitializerError(Dcl: LoopVar);
2534 return StmtError();
2535 }
2536
2537 return R;
2538}
2539
2540/// Create the initialization, compare, and increment steps for
2541/// the range-based for loop expression.
2542/// This function does not handle array-based for loops,
2543/// which are created in Sema::BuildCXXForRangeStmt.
2544///
2545/// \returns a ForRangeStatus indicating success or what kind of error occurred.
2546/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2547/// CandidateSet and BEF are set and some non-success value is returned on
2548/// failure.
2549static Sema::ForRangeStatus
2550BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2551 QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2552 SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2553 OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2554 ExprResult *EndExpr, BeginEndFunction *BEF) {
2555 DeclarationNameInfo BeginNameInfo(
2556 &SemaRef.PP.getIdentifierTable().get(Name: "begin"), ColonLoc);
2557 DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get(Name: "end"),
2558 ColonLoc);
2559
2560 LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2561 Sema::LookupMemberName);
2562 LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2563
2564 auto BuildBegin = [&] {
2565 *BEF = BEF_begin;
2566 Sema::ForRangeStatus RangeStatus =
2567 SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: BeginNameInfo,
2568 MemberLookup&: BeginMemberLookup, CandidateSet,
2569 Range: BeginRange, CallExpr: BeginExpr);
2570
2571 if (RangeStatus != Sema::FRS_Success) {
2572 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2573 SemaRef.Diag(Loc: BeginRange->getBeginLoc(), DiagID: diag::note_in_for_range)
2574 << ColonLoc << BEF_begin << BeginRange->getType();
2575 return RangeStatus;
2576 }
2577 if (!CoawaitLoc.isInvalid()) {
2578 // FIXME: getCurScope() should not be used during template instantiation.
2579 // We should pick up the set of unqualified lookup results for operator
2580 // co_await during the initial parse.
2581 *BeginExpr = SemaRef.ActOnCoawaitExpr(S: SemaRef.getCurScope(), KwLoc: ColonLoc,
2582 E: BeginExpr->get());
2583 if (BeginExpr->isInvalid())
2584 return Sema::FRS_DiagnosticIssued;
2585 }
2586 if (FinishForRangeVarDecl(SemaRef, Decl: BeginVar, Init: BeginExpr->get(), Loc: ColonLoc,
2587 DiagID: diag::err_for_range_iter_deduction_failure)) {
2588 NoteForRangeBeginEndFunction(SemaRef, E: BeginExpr->get(), BEF: *BEF);
2589 return Sema::FRS_DiagnosticIssued;
2590 }
2591 return Sema::FRS_Success;
2592 };
2593
2594 auto BuildEnd = [&] {
2595 *BEF = BEF_end;
2596 Sema::ForRangeStatus RangeStatus =
2597 SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: EndNameInfo,
2598 MemberLookup&: EndMemberLookup, CandidateSet,
2599 Range: EndRange, CallExpr: EndExpr);
2600 if (RangeStatus != Sema::FRS_Success) {
2601 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2602 SemaRef.Diag(Loc: EndRange->getBeginLoc(), DiagID: diag::note_in_for_range)
2603 << ColonLoc << BEF_end << EndRange->getType();
2604 return RangeStatus;
2605 }
2606 if (FinishForRangeVarDecl(SemaRef, Decl: EndVar, Init: EndExpr->get(), Loc: ColonLoc,
2607 DiagID: diag::err_for_range_iter_deduction_failure)) {
2608 NoteForRangeBeginEndFunction(SemaRef, E: EndExpr->get(), BEF: *BEF);
2609 return Sema::FRS_DiagnosticIssued;
2610 }
2611 return Sema::FRS_Success;
2612 };
2613
2614 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2615 // - if _RangeT is a class type, the unqualified-ids begin and end are
2616 // looked up in the scope of class _RangeT as if by class member access
2617 // lookup (3.4.5), and if either (or both) finds at least one
2618 // declaration, begin-expr and end-expr are __range.begin() and
2619 // __range.end(), respectively;
2620 SemaRef.LookupQualifiedName(R&: BeginMemberLookup, LookupCtx: D);
2621 if (BeginMemberLookup.isAmbiguous())
2622 return Sema::FRS_DiagnosticIssued;
2623
2624 SemaRef.LookupQualifiedName(R&: EndMemberLookup, LookupCtx: D);
2625 if (EndMemberLookup.isAmbiguous())
2626 return Sema::FRS_DiagnosticIssued;
2627
2628 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2629 // Look up the non-member form of the member we didn't find, first.
2630 // This way we prefer a "no viable 'end'" diagnostic over a "i found
2631 // a 'begin' but ignored it because there was no member 'end'"
2632 // diagnostic.
2633 auto BuildNonmember = [&](
2634 BeginEndFunction BEFFound, LookupResult &Found,
2635 llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
2636 llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
2637 LookupResult OldFound = std::move(Found);
2638 Found.clear();
2639
2640 if (Sema::ForRangeStatus Result = BuildNotFound())
2641 return Result;
2642
2643 switch (BuildFound()) {
2644 case Sema::FRS_Success:
2645 return Sema::FRS_Success;
2646
2647 case Sema::FRS_NoViableFunction:
2648 CandidateSet->NoteCandidates(
2649 PA: PartialDiagnosticAt(BeginRange->getBeginLoc(),
2650 SemaRef.PDiag(DiagID: diag::err_for_range_invalid)
2651 << BeginRange->getType() << BEFFound),
2652 S&: SemaRef, OCD: OCD_AllCandidates, Args: BeginRange);
2653 [[fallthrough]];
2654
2655 case Sema::FRS_DiagnosticIssued:
2656 for (NamedDecl *D : OldFound) {
2657 SemaRef.Diag(Loc: D->getLocation(),
2658 DiagID: diag::note_for_range_member_begin_end_ignored)
2659 << BeginRange->getType() << BEFFound;
2660 }
2661 return Sema::FRS_DiagnosticIssued;
2662 }
2663 llvm_unreachable("unexpected ForRangeStatus");
2664 };
2665 if (BeginMemberLookup.empty())
2666 return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
2667 return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin, BuildEnd);
2668 }
2669 } else {
2670 // - otherwise, begin-expr and end-expr are begin(__range) and
2671 // end(__range), respectively, where begin and end are looked up with
2672 // argument-dependent lookup (3.4.2). For the purposes of this name
2673 // lookup, namespace std is an associated namespace.
2674 }
2675
2676 if (Sema::ForRangeStatus Result = BuildBegin())
2677 return Result;
2678 return BuildEnd();
2679}
2680
2681/// Speculatively attempt to dereference an invalid range expression.
2682/// If the attempt fails, this function will return a valid, null StmtResult
2683/// and emit no diagnostics.
2684static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2685 SourceLocation ForLoc,
2686 SourceLocation CoawaitLoc,
2687 Stmt *InitStmt,
2688 Stmt *LoopVarDecl,
2689 SourceLocation ColonLoc,
2690 Expr *Range,
2691 SourceLocation RangeLoc,
2692 SourceLocation RParenLoc) {
2693 // Determine whether we can rebuild the for-range statement with a
2694 // dereferenced range expression.
2695 ExprResult AdjustedRange;
2696 {
2697 Sema::SFINAETrap Trap(SemaRef);
2698
2699 AdjustedRange = SemaRef.BuildUnaryOp(S, OpLoc: RangeLoc, Opc: UO_Deref, Input: Range);
2700 if (AdjustedRange.isInvalid())
2701 return StmtResult();
2702
2703 StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2704 S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2705 Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Check);
2706 if (SR.isInvalid())
2707 return StmtResult();
2708 }
2709
2710 // The attempt to dereference worked well enough that it could produce a valid
2711 // loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2712 // case there are any other (non-fatal) problems with it.
2713 SemaRef.Diag(Loc: RangeLoc, DiagID: diag::err_for_range_dereference)
2714 << Range->getType() << FixItHint::CreateInsertion(InsertionLoc: RangeLoc, Code: "*");
2715 return SemaRef.ActOnCXXForRangeStmt(
2716 S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2717 Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Rebuild);
2718}
2719
2720void Sema::ApplyForRangeOrExpansionStatementLifetimeExtension(
2721 VarDecl *RangeVar, ArrayRef<MaterializeTemporaryExpr *> Temporaries) {
2722 if (Temporaries.empty())
2723 return;
2724
2725 InitializedEntity Entity = InitializedEntity::InitializeVariable(Var: RangeVar);
2726 for (auto *MTE : Temporaries)
2727 MTE->setExtendingDecl(ExtendedBy: RangeVar, ManglingNumber: Entity.allocateManglingNumber());
2728}
2729
2730Sema::ForRangeBeginEndInfo Sema::BuildCXXForRangeBeginEndVars(
2731 Scope *S, VarDecl *RangeVar, SourceLocation ColonLoc,
2732 SourceLocation CoawaitLoc,
2733 ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps,
2734 BuildForRangeKind Kind, bool IsConstexpr, StmtResult *RebuildResult,
2735 llvm::function_ref<StmtResult()> RebuildWithDereference,
2736 IdentifierInfo *BeginName, IdentifierInfo *EndName) {
2737 QualType RangeVarType = RangeVar->getType();
2738 SourceLocation RangeLoc = RangeVar->getLocation();
2739 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2740
2741 ExprResult BeginRangeRef =
2742 BuildDeclRefExpr(D: RangeVar, Ty: RangeVarNonRefType, VK: VK_LValue, Loc: ColonLoc);
2743 if (BeginRangeRef.isInvalid())
2744 return {};
2745
2746 ExprResult EndRangeRef =
2747 BuildDeclRefExpr(D: RangeVar, Ty: RangeVarNonRefType, VK: VK_LValue, Loc: ColonLoc);
2748 if (EndRangeRef.isInvalid())
2749 return {};
2750
2751 QualType AutoType = Context.getAutoDeductType();
2752 Expr *Range = RangeVar->getInit();
2753 if (!Range)
2754 return {};
2755 QualType RangeType = Range->getType();
2756
2757 if (RequireCompleteType(Loc: RangeLoc, T: RangeType,
2758 DiagID: diag::err_for_range_incomplete_type))
2759 return {};
2760
2761 // Build auto __begin = begin-expr, __end = end-expr.
2762 // Divide by 2, since the variables are in the inner scope (loop body).
2763 const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2764 if (!BeginName)
2765 BeginName = PP.getIdentifierInfo(Name: std::string("__begin") + DepthStr);
2766 if (!EndName)
2767 EndName = PP.getIdentifierInfo(Name: std::string("__end") + DepthStr);
2768 VarDecl *BeginVar =
2769 BuildForRangeVarDecl(Loc: ColonLoc, Type: AutoType, II: BeginName, IsConstexpr);
2770 VarDecl *EndVar =
2771 BuildForRangeVarDecl(Loc: ColonLoc, Type: AutoType, II: EndName, IsConstexpr);
2772
2773 // Build begin-expr and end-expr and attach to __begin and __end variables.
2774 ExprResult BeginExpr, EndExpr;
2775 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2776 // - if _RangeT is an array type, begin-expr and end-expr are __range and
2777 // __range + __bound, respectively, where __bound is the array bound. If
2778 // _RangeT is an array of unknown size or an array of incomplete type,
2779 // the program is ill-formed;
2780
2781 // begin-expr is __range.
2782 BeginExpr = BeginRangeRef;
2783 if (!CoawaitLoc.isInvalid()) {
2784 BeginExpr = ActOnCoawaitExpr(S, KwLoc: ColonLoc, E: BeginExpr.get());
2785 if (BeginExpr.isInvalid())
2786 return {};
2787 }
2788 if (FinishForRangeVarDecl(SemaRef&: *this, Decl: BeginVar, Init: BeginRangeRef.get(), Loc: ColonLoc,
2789 DiagID: diag::err_for_range_iter_deduction_failure)) {
2790 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2791 return {};
2792 }
2793
2794 // Find the array bound.
2795 ExprResult BoundExpr;
2796 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Val: UnqAT))
2797 BoundExpr = IntegerLiteral::Create(
2798 C: Context, V: CAT->getSize(), type: Context.getPointerDiffType(), l: RangeLoc);
2799 else if (const VariableArrayType *VAT =
2800 dyn_cast<VariableArrayType>(Val: UnqAT)) {
2801 // For a variably modified type we can't just use the expression within
2802 // the array bounds, since we don't want that to be re-evaluated here.
2803 // Rather, we need to determine what it was when the array was first
2804 // created - so we resort to using sizeof(vla)/sizeof(element).
2805 // For e.g.
2806 // void f(int b) {
2807 // int vla[b];
2808 // b = -1; <-- This should not affect the num of iterations below
2809 // for (int &c : vla) { .. }
2810 // }
2811
2812 // FIXME: This results in codegen generating IR that recalculates the
2813 // run-time number of elements (as opposed to just using the IR Value
2814 // that corresponds to the run-time value of each bound that was
2815 // generated when the array was created.) If this proves too embarrassing
2816 // even for unoptimized IR, consider passing a magic-value/cookie to
2817 // codegen that then knows to simply use that initial llvm::Value (that
2818 // corresponds to the bound at time of array creation) within
2819 // getelementptr. But be prepared to pay the price of increasing a
2820 // customized form of coupling between the two components - which could
2821 // be hard to maintain as the codebase evolves.
2822
2823 ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2824 OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2825 /*IsType=*/true,
2826 TyOrEx: CreateParsedType(T: VAT->desugar(), TInfo: Context.getTrivialTypeSourceInfo(
2827 T: VAT->desugar(), Loc: RangeLoc))
2828 .getAsOpaquePtr(),
2829 ArgRange: EndVar->getSourceRange());
2830 if (SizeOfVLAExprR.isInvalid())
2831 return {};
2832
2833 ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2834 OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2835 /*IsType=*/true,
2836 TyOrEx: CreateParsedType(T: VAT->desugar(), TInfo: Context.getTrivialTypeSourceInfo(
2837 T: VAT->getElementType(), Loc: RangeLoc))
2838 .getAsOpaquePtr(),
2839 ArgRange: EndVar->getSourceRange());
2840 if (SizeOfEachElementExprR.isInvalid())
2841 return {};
2842
2843 BoundExpr =
2844 ActOnBinOp(S, TokLoc: EndVar->getLocation(), Kind: tok::slash, LHSExpr: SizeOfVLAExprR.get(),
2845 RHSExpr: SizeOfEachElementExprR.get());
2846 if (BoundExpr.isInvalid())
2847 return {};
2848
2849 } else {
2850 // Can't be a DependentSizedArrayType or an IncompleteArrayType since
2851 // UnqAT is not incomplete and Range is not type-dependent.
2852 llvm_unreachable("Unexpected array type in for-range");
2853 }
2854
2855 // end-expr is __range + __bound.
2856 EndExpr =
2857 ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::plus, LHSExpr: EndRangeRef.get(), RHSExpr: BoundExpr.get());
2858 if (EndExpr.isInvalid())
2859 return {};
2860 if (FinishForRangeVarDecl(SemaRef&: *this, Decl: EndVar, Init: EndExpr.get(), Loc: ColonLoc,
2861 DiagID: diag::err_for_range_iter_deduction_failure)) {
2862 NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
2863 return {};
2864 }
2865 } else {
2866 OverloadCandidateSet CandidateSet(RangeLoc,
2867 OverloadCandidateSet::CSK_Normal);
2868 BeginEndFunction BEFFailure;
2869 ForRangeStatus RangeStatus =
2870 BuildNonArrayForRange(SemaRef&: *this, BeginRange: BeginRangeRef.get(), EndRange: EndRangeRef.get(),
2871 RangeType, BeginVar, EndVar, ColonLoc, CoawaitLoc,
2872 CandidateSet: &CandidateSet, BeginExpr: &BeginExpr, EndExpr: &EndExpr, BEF: &BEFFailure);
2873
2874 if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2875 BEFFailure == BEF_begin) {
2876 // If the range is being built from an array parameter, emit a
2877 // a diagnostic that it is being treated as a pointer.
2878 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Range)) {
2879 if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Val: DRE->getDecl())) {
2880 QualType ArrayTy = PVD->getOriginalType();
2881 QualType PointerTy = PVD->getType();
2882 if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2883 Diag(Loc: Range->getBeginLoc(), DiagID: diag::err_range_on_array_parameter)
2884 << RangeLoc << PVD << ArrayTy << PointerTy;
2885 Diag(Loc: PVD->getLocation(), DiagID: diag::note_declared_at);
2886 return {};
2887 }
2888 }
2889 }
2890
2891 // If building the range failed, try dereferencing the range expression
2892 // unless a diagnostic was issued or the end function is problematic.
2893 if (RebuildWithDereference) {
2894 assert(RebuildResult);
2895 StmtResult SR = RebuildWithDereference();
2896 if (SR.isInvalid() || SR.isUsable()) {
2897 *RebuildResult = SR;
2898 return {};
2899 }
2900 }
2901 }
2902
2903 // Otherwise, emit diagnostics if we haven't already.
2904 if (RangeStatus == FRS_NoViableFunction) {
2905 Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2906 CandidateSet.NoteCandidates(
2907 PA: PartialDiagnosticAt(Range->getBeginLoc(),
2908 PDiag(DiagID: diag::err_for_range_invalid)
2909 << RangeLoc << Range->getType()
2910 << BEFFailure),
2911 S&: *this, OCD: OCD_AllCandidates, Args: Range);
2912 }
2913 // Return an error if no fix was discovered.
2914 if (RangeStatus != FRS_Success)
2915 return {};
2916 }
2917
2918 assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
2919 "invalid range expression in for loop");
2920
2921 return {.BeginVar: BeginVar, .EndVar: EndVar, .BeginExpr: BeginExpr.get(), .EndExpr: EndExpr.get()};
2922}
2923
2924void Sema::ActOnDependentForRangeInitializer(VarDecl *LoopVar,
2925 BuildForRangeKind BFRK) {
2926 // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2927 // them in properly when we instantiate the loop.
2928 if (!LoopVar->isInvalidDecl() && BFRK != BFRK_Check) {
2929 if (auto *DD = dyn_cast<DecompositionDecl>(Val: LoopVar))
2930 for (auto *Binding : DD->bindings()) {
2931 if (!Binding->isParameterPack())
2932 Binding->setType(Context.DependentTy);
2933 }
2934 LoopVar->setType(SubstAutoTypeDependent(TypeWithAuto: LoopVar->getType()));
2935 }
2936}
2937
2938StmtResult Sema::BuildCXXForRangeStmt(
2939 SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2940 SourceLocation ColonLoc, Stmt *RangeDecl, Stmt *Begin, Stmt *End,
2941 Expr *Cond, Expr *Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
2942 BuildForRangeKind Kind,
2943 ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2944 // FIXME: This should not be used during template instantiation. We should
2945 // pick up the set of unqualified lookup results for the != and + operators
2946 // in the initial parse.
2947 //
2948 // Testcase (accepts-invalid):
2949 // template<typename T> void f() { for (auto x : T()) {} }
2950 // namespace N { struct X { X begin(); X end(); int operator*(); }; }
2951 // bool operator!=(N::X, N::X); void operator++(N::X);
2952 // void g() { f<N::X>(); }
2953 Scope *S = getCurScope();
2954
2955 DeclStmt *RangeDS = cast<DeclStmt>(Val: RangeDecl);
2956 VarDecl *RangeVar = cast<VarDecl>(Val: RangeDS->getSingleDecl());
2957 QualType RangeVarType = RangeVar->getType();
2958
2959 DeclStmt *LoopVarDS = cast<DeclStmt>(Val: LoopVarDecl);
2960 VarDecl *LoopVar = cast<VarDecl>(Val: LoopVarDS->getSingleDecl());
2961
2962 StmtResult BeginDeclStmt = Begin;
2963 StmtResult EndDeclStmt = End;
2964 ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2965
2966 if (RangeVarType->isDependentType()) {
2967 // The range is implicitly used as a placeholder when it is dependent.
2968 RangeVar->markUsed(C&: Context);
2969 ActOnDependentForRangeInitializer(LoopVar, BFRK: Kind);
2970 } else if (!BeginDeclStmt.get()) {
2971 StmtResult RebuildResult;
2972 auto RebuildWithDereference = [&] {
2973 return RebuildForRangeWithDereference(
2974 SemaRef&: *this, S, ForLoc, CoawaitLoc, InitStmt, LoopVarDecl, ColonLoc,
2975 Range: RangeVar->getInit(), RangeLoc: RangeVar->getLocation(), RParenLoc);
2976 };
2977
2978 ForRangeBeginEndInfo ForRangeInfo = BuildCXXForRangeBeginEndVars(
2979 S, RangeVar, ColonLoc, CoawaitLoc, LifetimeExtendTemps, Kind,
2980 /*Constexpr=*/IsConstexpr: false, RebuildResult: &RebuildResult, RebuildWithDereference);
2981
2982 if (!RebuildResult.isUnset())
2983 return RebuildResult;
2984 if (!ForRangeInfo.isValid())
2985 return StmtError();
2986
2987 // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2988 // C++1z removes this restriction.
2989 auto [BeginVar, EndVar, BeginExpr, EndExpr] = ForRangeInfo;
2990 SourceLocation RangeLoc = RangeVar->getLocation();
2991 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2992 if (!Context.hasSameType(T1: BeginType, T2: EndType)) {
2993 Diag(Loc: RangeLoc, DiagID: getLangOpts().CPlusPlus17
2994 ? diag::warn_for_range_begin_end_types_differ
2995 : diag::ext_for_range_begin_end_types_differ)
2996 << BeginType << EndType;
2997 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr, BEF: BEF_begin);
2998 NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr, BEF: BEF_end);
2999 }
3000
3001 BeginDeclStmt =
3002 ActOnDeclStmt(dg: ConvertDeclToDeclGroup(Ptr: BeginVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
3003 EndDeclStmt =
3004 ActOnDeclStmt(dg: ConvertDeclToDeclGroup(Ptr: EndVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
3005
3006 const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
3007 ExprResult BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
3008 VK: VK_LValue, Loc: ColonLoc);
3009 if (BeginRef.isInvalid())
3010 return StmtError();
3011
3012 ExprResult EndRef = BuildDeclRefExpr(D: EndVar, Ty: EndType.getNonReferenceType(),
3013 VK: VK_LValue, Loc: ColonLoc);
3014 if (EndRef.isInvalid())
3015 return StmtError();
3016
3017 // Build and check __begin != __end expression.
3018 NotEqExpr = ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::exclaimequal,
3019 LHSExpr: BeginRef.get(), RHSExpr: EndRef.get());
3020 if (!NotEqExpr.isInvalid())
3021 NotEqExpr = CheckBooleanCondition(Loc: ColonLoc, E: NotEqExpr.get());
3022 if (!NotEqExpr.isInvalid())
3023 NotEqExpr =
3024 ActOnFinishFullExpr(Expr: NotEqExpr.get(), /*DiscardedValue*/ false);
3025 if (NotEqExpr.isInvalid()) {
3026 Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
3027 << RangeLoc << diag::InvalidRangeForIterator::OpNotEq
3028 << BeginRef.get()->getType();
3029 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr, BEF: BEF_begin);
3030 if (!Context.hasSameType(T1: BeginType, T2: EndType))
3031 NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr, BEF: BEF_end);
3032 return StmtError();
3033 }
3034
3035 // Build and check ++__begin expression.
3036 BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
3037 VK: VK_LValue, Loc: ColonLoc);
3038 if (BeginRef.isInvalid())
3039 return StmtError();
3040
3041 IncrExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::plusplus, Input: BeginRef.get());
3042 if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
3043 // FIXME: getCurScope() should not be used during template instantiation.
3044 // We should pick up the set of unqualified lookup results for operator
3045 // co_await during the initial parse.
3046 IncrExpr = ActOnCoawaitExpr(S, KwLoc: CoawaitLoc, E: IncrExpr.get());
3047 if (!IncrExpr.isInvalid())
3048 IncrExpr = ActOnFinishFullExpr(Expr: IncrExpr.get(), /*DiscardedValue*/ false);
3049 if (IncrExpr.isInvalid()) {
3050 Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
3051 << RangeLoc << diag::InvalidRangeForIterator::OpAdvance
3052 << BeginRef.get()->getType();
3053 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr, BEF: BEF_begin);
3054 return StmtError();
3055 }
3056
3057 // Build and check *__begin expression.
3058 BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
3059 VK: VK_LValue, Loc: ColonLoc);
3060 if (BeginRef.isInvalid())
3061 return StmtError();
3062
3063 ExprResult DerefExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::star, Input: BeginRef.get());
3064 if (DerefExpr.isInvalid()) {
3065 Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
3066 << RangeLoc << diag::InvalidRangeForIterator::OpDeref
3067 << BeginRef.get()->getType();
3068 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr, BEF: BEF_begin);
3069 return StmtError();
3070 }
3071
3072 // Attach *__begin as initializer for VD. Don't touch it if we're just
3073 // trying to determine whether this would be a valid range.
3074 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
3075 AddInitializerToDecl(dcl: LoopVar, init: DerefExpr.get(), /*DirectInit=*/false);
3076 if (LoopVar->isInvalidDecl() ||
3077 (LoopVar->getInit() && LoopVar->getInit()->containsErrors()))
3078 NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr, BEF: BEF_begin);
3079 }
3080 }
3081
3082 // Don't bother to actually allocate the result if we're just trying to
3083 // determine whether it would be valid.
3084 if (Kind == BFRK_Check)
3085 return StmtResult();
3086
3087 // In OpenMP loop region loop control variable must be private. Perform
3088 // analysis of first part (if any).
3089 if (getLangOpts().OpenMP >= 50 && BeginDeclStmt.isUsable())
3090 OpenMP().ActOnOpenMPLoopInitialization(ForLoc, Init: BeginDeclStmt.get());
3091
3092 // P2718R0 - Lifetime extension in range-based for loops.
3093 if (getLangOpts().CPlusPlus23)
3094 ApplyForRangeOrExpansionStatementLifetimeExtension(RangeVar,
3095 Temporaries: LifetimeExtendTemps);
3096
3097 return new (Context) CXXForRangeStmt(
3098 InitStmt, RangeDS, cast_or_null<DeclStmt>(Val: BeginDeclStmt.get()),
3099 cast_or_null<DeclStmt>(Val: EndDeclStmt.get()), NotEqExpr.get(),
3100 IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
3101 ColonLoc, RParenLoc);
3102}
3103
3104// Warn when the loop variable is a const reference that creates a copy.
3105// Suggest using the non-reference type for copies. If a copy can be prevented
3106// suggest the const reference type that would do so.
3107// For instance, given "for (const &Foo : Range)", suggest
3108// "for (const Foo : Range)" to denote a copy is made for the loop. If
3109// possible, also suggest "for (const &Bar : Range)" if this type prevents
3110// the copy altogether.
3111static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
3112 const VarDecl *VD,
3113 QualType RangeInitType) {
3114 const Expr *InitExpr = VD->getInit();
3115 if (!InitExpr)
3116 return;
3117
3118 QualType VariableType = VD->getType();
3119
3120 if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: InitExpr))
3121 if (!Cleanups->cleanupsHaveSideEffects())
3122 InitExpr = Cleanups->getSubExpr();
3123
3124 const MaterializeTemporaryExpr *MTE =
3125 dyn_cast<MaterializeTemporaryExpr>(Val: InitExpr);
3126
3127 // No copy made.
3128 if (!MTE)
3129 return;
3130
3131 const Expr *E = MTE->getSubExpr()->IgnoreImpCasts();
3132
3133 // Searching for either UnaryOperator for dereference of a pointer or
3134 // CXXOperatorCallExpr for handling iterators.
3135 while (!isa<CXXOperatorCallExpr>(Val: E) && !isa<UnaryOperator>(Val: E)) {
3136 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Val: E)) {
3137 E = CCE->getArg(Arg: 0);
3138 } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(Val: E)) {
3139 const MemberExpr *ME = cast<MemberExpr>(Val: Call->getCallee());
3140 E = ME->getBase();
3141 } else {
3142 const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(Val: E);
3143 E = MTE->getSubExpr();
3144 }
3145 E = E->IgnoreImpCasts();
3146 }
3147
3148 QualType ReferenceReturnType;
3149 if (isa<UnaryOperator>(Val: E)) {
3150 ReferenceReturnType = SemaRef.Context.getLValueReferenceType(T: E->getType());
3151 } else {
3152 const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(Val: E);
3153 const FunctionDecl *FD = Call->getDirectCallee();
3154 QualType ReturnType = FD->getReturnType();
3155 if (ReturnType->isReferenceType())
3156 ReferenceReturnType = ReturnType;
3157 }
3158
3159 if (!ReferenceReturnType.isNull()) {
3160 // Loop variable creates a temporary. Suggest either to go with
3161 // non-reference loop variable to indicate a copy is made, or
3162 // the correct type to bind a const reference.
3163 SemaRef.Diag(Loc: VD->getLocation(),
3164 DiagID: diag::warn_for_range_const_ref_binds_temp_built_from_ref)
3165 << VD << VariableType << ReferenceReturnType;
3166 QualType NonReferenceType = VariableType.getNonReferenceType();
3167 NonReferenceType.removeLocalConst();
3168 QualType NewReferenceType =
3169 SemaRef.Context.getLValueReferenceType(T: E->getType().withConst());
3170 SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_type_or_non_reference)
3171 << NonReferenceType << NewReferenceType << VD->getSourceRange()
3172 << FixItHint::CreateRemoval(RemoveRange: VD->getTypeSpecEndLoc());
3173 } else if (!VariableType->isRValueReferenceType()) {
3174 // The range always returns a copy, so a temporary is always created.
3175 // Suggest removing the reference from the loop variable.
3176 // If the type is a rvalue reference do not warn since that changes the
3177 // semantic of the code.
3178 SemaRef.Diag(Loc: VD->getLocation(), DiagID: diag::warn_for_range_ref_binds_ret_temp)
3179 << VD << RangeInitType;
3180 QualType NonReferenceType = VariableType.getNonReferenceType();
3181 NonReferenceType.removeLocalConst();
3182 SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_non_reference_type)
3183 << NonReferenceType << VD->getSourceRange()
3184 << FixItHint::CreateRemoval(RemoveRange: VD->getTypeSpecEndLoc());
3185 }
3186}
3187
3188/// Determines whether the @p VariableType's declaration is a record with the
3189/// clang::trivial_abi attribute.
3190static bool hasTrivialABIAttr(QualType VariableType) {
3191 if (CXXRecordDecl *RD = VariableType->getAsCXXRecordDecl())
3192 return RD->hasAttr<TrivialABIAttr>();
3193
3194 return false;
3195}
3196
3197// Warns when the loop variable can be changed to a reference type to
3198// prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
3199// "for (const Foo &x : Range)" if this form does not make a copy.
3200static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
3201 const VarDecl *VD) {
3202 const Expr *InitExpr = VD->getInit();
3203 if (!InitExpr)
3204 return;
3205
3206 QualType VariableType = VD->getType();
3207
3208 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: InitExpr)) {
3209 if (!CE->getConstructor()->isCopyConstructor())
3210 return;
3211 } else if (const CastExpr *CE = dyn_cast<CastExpr>(Val: InitExpr)) {
3212 if (CE->getCastKind() != CK_LValueToRValue)
3213 return;
3214 } else {
3215 return;
3216 }
3217
3218 // Small trivially copyable types are cheap to copy. Do not emit the
3219 // diagnostic for these instances. 64 bytes is a common size of a cache line.
3220 // (The function `getTypeSize` returns the size in bits.)
3221 ASTContext &Ctx = SemaRef.Context;
3222 if (Ctx.getTypeSize(T: VariableType) <= 64 * 8 &&
3223 (VariableType.isTriviallyCopyConstructibleType(Context: Ctx) ||
3224 hasTrivialABIAttr(VariableType)))
3225 return;
3226
3227 // Suggest changing from a const variable to a const reference variable
3228 // if doing so will prevent a copy.
3229 SemaRef.Diag(Loc: VD->getLocation(), DiagID: diag::warn_for_range_copy)
3230 << VD << VariableType;
3231 SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_reference_type)
3232 << SemaRef.Context.getLValueReferenceType(T: VariableType)
3233 << VD->getSourceRange()
3234 << FixItHint::CreateInsertion(InsertionLoc: VD->getLocation(), Code: "&");
3235}
3236
3237/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
3238/// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
3239/// using "const foo x" to show that a copy is made
3240/// 2) for (const bar &x : foos) where bar is a temporary initialized by bar.
3241/// Suggest either "const bar x" to keep the copying or "const foo& x" to
3242/// prevent the copy.
3243/// 3) for (const foo x : foos) where x is constructed from a reference foo.
3244/// Suggest "const foo &x" to prevent the copy.
3245static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
3246 const CXXForRangeStmt *ForStmt) {
3247 if (SemaRef.inTemplateInstantiation())
3248 return;
3249
3250 SourceLocation Loc = ForStmt->getBeginLoc();
3251 if (SemaRef.Diags.isIgnored(
3252 DiagID: diag::warn_for_range_const_ref_binds_temp_built_from_ref, Loc) &&
3253 SemaRef.Diags.isIgnored(DiagID: diag::warn_for_range_ref_binds_ret_temp, Loc) &&
3254 SemaRef.Diags.isIgnored(DiagID: diag::warn_for_range_copy, Loc)) {
3255 return;
3256 }
3257
3258 const VarDecl *VD = ForStmt->getLoopVariable();
3259 if (!VD)
3260 return;
3261
3262 QualType VariableType = VD->getType();
3263
3264 if (VariableType->isIncompleteType())
3265 return;
3266
3267 const Expr *InitExpr = VD->getInit();
3268 if (!InitExpr)
3269 return;
3270
3271 if (InitExpr->getExprLoc().isMacroID())
3272 return;
3273
3274 if (VariableType->isReferenceType()) {
3275 DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
3276 RangeInitType: ForStmt->getRangeInit()->getType());
3277 } else if (VariableType.isConstQualified()) {
3278 DiagnoseForRangeConstVariableCopies(SemaRef, VD);
3279 }
3280}
3281
3282StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
3283 if (!S || !B)
3284 return StmtError();
3285
3286 if (isa<ObjCForCollectionStmt>(Val: S))
3287 return ObjC().FinishObjCForCollectionStmt(ForCollection: S, Body: B);
3288
3289 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(Val: S);
3290 ForStmt->setBody(B);
3291
3292 DiagnoseEmptyStmtBody(StmtLoc: ForStmt->getRParenLoc(), Body: B,
3293 DiagID: diag::warn_empty_range_based_for_body);
3294
3295 DiagnoseForRangeVariableCopies(SemaRef&: *this, ForStmt);
3296
3297 return S;
3298}
3299
3300StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
3301 SourceLocation LabelLoc,
3302 LabelDecl *TheDecl) {
3303 setFunctionHasBranchIntoScope();
3304
3305 // If this goto is in a compute construct scope, we need to make sure we check
3306 // gotos in/out.
3307 if (getCurScope()->isInOpenACCComputeConstructScope())
3308 setFunctionHasBranchProtectedScope();
3309
3310 TheDecl->markUsed(C&: Context);
3311 return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
3312}
3313
3314StmtResult
3315Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
3316 Expr *E) {
3317 // Convert operand to void*
3318 if (!E->isTypeDependent()) {
3319 QualType ETy = E->getType();
3320 QualType DestTy = Context.getPointerType(T: Context.VoidTy.withConst());
3321 ExprResult ExprRes = E;
3322 AssignConvertType ConvTy =
3323 CheckSingleAssignmentConstraints(LHSType: DestTy, RHS&: ExprRes);
3324 if (ExprRes.isInvalid())
3325 return StmtError();
3326 E = ExprRes.get();
3327 if (DiagnoseAssignmentResult(ConvTy, Loc: StarLoc, DstType: DestTy, SrcType: ETy, SrcExpr: E,
3328 Action: AssignmentAction::Passing))
3329 return StmtError();
3330 }
3331
3332 ExprResult ExprRes = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
3333 if (ExprRes.isInvalid())
3334 return StmtError();
3335 E = ExprRes.get();
3336
3337 setFunctionHasIndirectGoto();
3338
3339 // If this goto is in a compute construct scope, we need to make sure we
3340 // check gotos in/out.
3341 if (getCurScope()->isInOpenACCComputeConstructScope())
3342 setFunctionHasBranchProtectedScope();
3343
3344 return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
3345}
3346
3347static void CheckJumpOutOfSEHFinallyOrDefer(Sema &S, SourceLocation Loc,
3348 const Scope &DestScope,
3349 unsigned DeferJumpKind) {
3350 if (!S.CurrentSEHFinally.empty() &&
3351 DestScope.Contains(rhs: *S.CurrentSEHFinally.back())) {
3352 S.Diag(Loc, DiagID: diag::warn_jump_out_of_seh_finally);
3353 }
3354
3355 if (!S.CurrentDefer.empty()) {
3356 Scope *Parent = S.CurrentDefer.back().first;
3357 assert(Parent);
3358
3359 // Note: We don't create a new scope for defer statements, so 'Parent'
3360 // is actually the scope that contains the '_Defer'.
3361 if (DestScope.Contains(rhs: *Parent) || &DestScope == Parent)
3362 S.Diag(Loc, DiagID: diag::err_jump_out_of_defer_stmt) << DeferJumpKind;
3363 }
3364}
3365
3366static Scope *FindLabeledBreakContinueScope(Sema &S, Scope *CurScope,
3367 SourceLocation KWLoc,
3368 LabelDecl *Target,
3369 SourceLocation LabelLoc,
3370 bool IsContinue) {
3371 assert(Target && "not a named break/continue?");
3372
3373 Target->markUsed(C&: S.Context);
3374
3375 Scope *Found = nullptr;
3376 for (Scope *Scope = CurScope; Scope; Scope = Scope->getParent()) {
3377 if (Scope->isFunctionScope())
3378 break;
3379
3380 if (Scope->isOpenACCComputeConstructScope()) {
3381 S.Diag(Loc: KWLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3382 << /*branch*/ 0 << /*out of*/ 0;
3383 return nullptr;
3384 }
3385
3386 if (Scope->isBreakOrContinueScope() &&
3387 Scope->getPrecedingLabel() == Target) {
3388 Found = Scope;
3389 break;
3390 }
3391 }
3392
3393 if (Found) {
3394 if (IsContinue && !Found->isContinueScope()) {
3395 S.Diag(Loc: LabelLoc, DiagID: diag::err_continue_switch);
3396 return nullptr;
3397 }
3398 return Found;
3399 }
3400
3401 S.Diag(Loc: LabelLoc, DiagID: diag::err_break_continue_label_not_found) << IsContinue;
3402 return nullptr;
3403}
3404
3405StmtResult Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope,
3406 LabelDecl *Target, SourceLocation LabelLoc) {
3407 Scope *S;
3408 if (Target) {
3409 S = FindLabeledBreakContinueScope(S&: *this, CurScope, KWLoc: ContinueLoc, Target,
3410 LabelLoc,
3411 /*IsContinue=*/true);
3412 if (!S)
3413 return StmtError();
3414 } else {
3415 S = CurScope->getContinueParent();
3416 }
3417
3418 if (!S) {
3419 // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
3420 return StmtError(Diag(Loc: ContinueLoc, DiagID: diag::err_continue_not_in_loop));
3421 }
3422
3423 // A 'continue' that would normally have execution continue on a block outside
3424 // of a compute construct counts as 'branching out of' the compute construct,
3425 // so diagnose here.
3426 if (S->isOpenACCComputeConstructScope())
3427 return StmtError(
3428 Diag(Loc: ContinueLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3429 << /*branch*/ 0 << /*out of */ 0);
3430
3431 CheckJumpOutOfSEHFinallyOrDefer(S&: *this, Loc: ContinueLoc, DestScope: *S,
3432 DeferJumpKind: diag::DeferJumpKind::Continue);
3433
3434 return new (Context) ContinueStmt(ContinueLoc, LabelLoc, Target);
3435}
3436
3437StmtResult Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope,
3438 LabelDecl *Target, SourceLocation LabelLoc) {
3439 Scope *S;
3440 if (Target) {
3441 S = FindLabeledBreakContinueScope(S&: *this, CurScope, KWLoc: BreakLoc, Target,
3442 LabelLoc,
3443 /*IsContinue=*/false);
3444 if (!S)
3445 return StmtError();
3446 } else {
3447 S = CurScope->getBreakParent();
3448 }
3449
3450 if (!S) {
3451 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
3452 return StmtError(Diag(Loc: BreakLoc, DiagID: diag::err_break_not_in_loop_or_switch));
3453 }
3454
3455 if (S->isOpenMPLoopScope())
3456 return StmtError(Diag(Loc: BreakLoc, DiagID: diag::err_omp_loop_cannot_use_stmt)
3457 << "break");
3458
3459 // OpenACC doesn't allow 'break'ing from a compute construct, so diagnose if
3460 // we are trying to do so. This can come in 2 flavors: 1-the break'able thing
3461 // (besides the compute construct) 'contains' the compute construct, at which
3462 // point the 'break' scope will be the compute construct. Else it could be a
3463 // loop of some sort that has a direct parent of the compute construct.
3464 // However, a 'break' in a 'switch' marked as a compute construct doesn't
3465 // count as 'branch out of' the compute construct.
3466 if (S->isOpenACCComputeConstructScope() ||
3467 (S->isLoopScope() && S->getParent() &&
3468 S->getParent()->isOpenACCComputeConstructScope()))
3469 return StmtError(
3470 Diag(Loc: BreakLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3471 << /*branch*/ 0 << /*out of */ 0);
3472
3473 CheckJumpOutOfSEHFinallyOrDefer(S&: *this, Loc: BreakLoc, DestScope: *S,
3474 DeferJumpKind: diag::DeferJumpKind::Break);
3475
3476 return new (Context) BreakStmt(BreakLoc, LabelLoc, Target);
3477}
3478
3479Sema::NamedReturnInfo Sema::getNamedReturnInfo(Expr *&E,
3480 SimplerImplicitMoveMode Mode) {
3481 if (!E)
3482 return NamedReturnInfo();
3483 // - in a return statement in a function [where] ...
3484 // ... the expression is the name of a non-volatile automatic object ...
3485 const auto *DR = dyn_cast<DeclRefExpr>(Val: E->IgnoreParens());
3486 if (!DR || DR->refersToEnclosingVariableOrCapture())
3487 return NamedReturnInfo();
3488 const auto *VD = dyn_cast<VarDecl>(Val: DR->getDecl());
3489 if (!VD)
3490 return NamedReturnInfo();
3491 if (VD->getInit() && VD->getInit()->containsErrors())
3492 return NamedReturnInfo();
3493 NamedReturnInfo Res = getNamedReturnInfo(VD);
3494 if (Res.Candidate && !E->isXValue() &&
3495 (Mode == SimplerImplicitMoveMode::ForceOn ||
3496 (Mode != SimplerImplicitMoveMode::ForceOff &&
3497 getLangOpts().CPlusPlus23))) {
3498 E = ImplicitCastExpr::Create(Context, T: VD->getType().getNonReferenceType(),
3499 Kind: CK_NoOp, Operand: E, BasePath: nullptr, Cat: VK_XValue,
3500 FPO: FPOptionsOverride());
3501 }
3502 return Res;
3503}
3504
3505Sema::NamedReturnInfo Sema::getNamedReturnInfo(const VarDecl *VD) {
3506 NamedReturnInfo Info{.Candidate: VD, .S: NamedReturnInfo::MoveEligibleAndCopyElidable};
3507
3508 // C++20 [class.copy.elision]p3:
3509 // - in a return statement in a function with ...
3510 // (other than a function ... parameter)
3511 if (VD->getKind() == Decl::ParmVar)
3512 Info.S = NamedReturnInfo::MoveEligible;
3513 else if (VD->getKind() != Decl::Var)
3514 return NamedReturnInfo();
3515
3516 // (other than ... a catch-clause parameter)
3517 if (VD->isExceptionVariable())
3518 Info.S = NamedReturnInfo::MoveEligible;
3519
3520 // ...automatic...
3521 if (!VD->hasLocalStorage())
3522 return NamedReturnInfo();
3523
3524 // We don't want to implicitly move out of a __block variable during a return
3525 // because we cannot assume the variable will no longer be used.
3526 if (VD->hasAttr<BlocksAttr>())
3527 return NamedReturnInfo();
3528
3529 QualType VDType = VD->getType();
3530 if (VDType->isObjectType()) {
3531 // C++17 [class.copy.elision]p3:
3532 // ...non-volatile automatic object...
3533 if (VDType.isVolatileQualified())
3534 return NamedReturnInfo();
3535 } else if (VDType->isRValueReferenceType()) {
3536 // C++20 [class.copy.elision]p3:
3537 // ...either a non-volatile object or an rvalue reference to a non-volatile
3538 // object type...
3539 QualType VDReferencedType = VDType.getNonReferenceType();
3540 if (VDReferencedType.isVolatileQualified() ||
3541 !VDReferencedType->isObjectType())
3542 return NamedReturnInfo();
3543 Info.S = NamedReturnInfo::MoveEligible;
3544 } else {
3545 return NamedReturnInfo();
3546 }
3547
3548 // Variables with higher required alignment than their type's ABI
3549 // alignment cannot use NRVO.
3550 if (!VD->hasDependentAlignment() && !VDType->isIncompleteType() &&
3551 Context.getDeclAlign(D: VD) > Context.getTypeAlignInChars(T: VDType))
3552 Info.S = NamedReturnInfo::MoveEligible;
3553
3554 return Info;
3555}
3556
3557const VarDecl *Sema::getCopyElisionCandidate(NamedReturnInfo &Info,
3558 QualType ReturnType) {
3559 if (!Info.Candidate)
3560 return nullptr;
3561
3562 auto invalidNRVO = [&] {
3563 Info = NamedReturnInfo();
3564 return nullptr;
3565 };
3566
3567 // If we got a non-deduced auto ReturnType, we are in a dependent context and
3568 // there is no point in allowing copy elision since we won't have it deduced
3569 // by the point the VardDecl is instantiated, which is the last chance we have
3570 // of deciding if the candidate is really copy elidable.
3571 if ((ReturnType->getTypeClass() == Type::TypeClass::Auto &&
3572 ReturnType->isCanonicalUnqualified()) ||
3573 ReturnType->isSpecificBuiltinType(K: BuiltinType::Dependent))
3574 return invalidNRVO();
3575
3576 if (!ReturnType->isDependentType()) {
3577 // - in a return statement in a function with ...
3578 // ... a class return type ...
3579 if (!ReturnType->isRecordType())
3580 return invalidNRVO();
3581
3582 QualType VDType = Info.Candidate->getType();
3583 // ... the same cv-unqualified type as the function return type ...
3584 // When considering moving this expression out, allow dissimilar types.
3585 if (!VDType->isDependentType() &&
3586 !Context.hasSameUnqualifiedType(T1: ReturnType, T2: VDType))
3587 Info.S = NamedReturnInfo::MoveEligible;
3588 }
3589 return Info.isCopyElidable() ? Info.Candidate : nullptr;
3590}
3591
3592/// Verify that the initialization sequence that was picked for the
3593/// first overload resolution is permissible under C++98.
3594///
3595/// Reject (possibly converting) constructors not taking an rvalue reference,
3596/// or user conversion operators which are not ref-qualified.
3597static bool
3598VerifyInitializationSequenceCXX98(const Sema &S,
3599 const InitializationSequence &Seq) {
3600 const auto *Step = llvm::find_if(Range: Seq.steps(), P: [](const auto &Step) {
3601 return Step.Kind == InitializationSequence::SK_ConstructorInitialization ||
3602 Step.Kind == InitializationSequence::SK_UserConversion;
3603 });
3604 if (Step != Seq.step_end()) {
3605 const auto *FD = Step->Function.Function;
3606 if (isa<CXXConstructorDecl>(Val: FD)
3607 ? !FD->getParamDecl(i: 0)->getType()->isRValueReferenceType()
3608 : cast<CXXMethodDecl>(Val: FD)->getRefQualifier() == RQ_None)
3609 return false;
3610 }
3611 return true;
3612}
3613
3614ExprResult Sema::PerformMoveOrCopyInitialization(
3615 const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
3616 bool SupressSimplerImplicitMoves) {
3617 if (getLangOpts().CPlusPlus &&
3618 (!getLangOpts().CPlusPlus23 || SupressSimplerImplicitMoves) &&
3619 NRInfo.isMoveEligible()) {
3620 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
3621 CK_NoOp, Value, VK_XValue, FPOptionsOverride());
3622 Expr *InitExpr = &AsRvalue;
3623 auto Kind = InitializationKind::CreateCopy(InitLoc: Value->getBeginLoc(),
3624 EqualLoc: Value->getBeginLoc());
3625 InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3626 auto Res = Seq.getFailedOverloadResult();
3627 if ((Res == OR_Success || Res == OR_Deleted) &&
3628 (getLangOpts().CPlusPlus11 ||
3629 VerifyInitializationSequenceCXX98(S: *this, Seq))) {
3630 // Promote "AsRvalue" to the heap, since we now need this
3631 // expression node to persist.
3632 Value =
3633 ImplicitCastExpr::Create(Context, T: Value->getType(), Kind: CK_NoOp, Operand: Value,
3634 BasePath: nullptr, Cat: VK_XValue, FPO: FPOptionsOverride());
3635 // Complete type-checking the initialization of the return type
3636 // using the constructor we found.
3637 return Seq.Perform(S&: *this, Entity, Kind, Args: Value);
3638 }
3639 }
3640 // Either we didn't meet the criteria for treating an lvalue as an rvalue,
3641 // above, or overload resolution failed. Either way, we need to try
3642 // (again) now with the return value expression as written.
3643 return PerformCopyInitialization(Entity, EqualLoc: SourceLocation(), Init: Value);
3644}
3645
3646/// Determine whether the declared return type of the specified function
3647/// contains 'auto'.
3648static bool hasDeducedReturnType(FunctionDecl *FD) {
3649 const FunctionProtoType *FPT =
3650 FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
3651 return FPT->getReturnType()->isUndeducedType();
3652}
3653
3654StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
3655 Expr *RetValExp,
3656 NamedReturnInfo &NRInfo,
3657 bool SupressSimplerImplicitMoves) {
3658 // If this is the first return we've seen, infer the return type.
3659 // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
3660 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(Val: getCurFunction());
3661 QualType FnRetType = CurCap->ReturnType;
3662 LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(Val: CurCap);
3663 if (CurLambda && CurLambda->CallOperator->getType().isNull())
3664 return StmtError();
3665 bool HasDeducedReturnType =
3666 CurLambda && hasDeducedReturnType(FD: CurLambda->CallOperator);
3667
3668 if (ExprEvalContexts.back().isDiscardedStatementContext() &&
3669 (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
3670 if (RetValExp) {
3671 ExprResult ER =
3672 ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3673 if (ER.isInvalid())
3674 return StmtError();
3675 RetValExp = ER.get();
3676 }
3677 return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
3678 /* NRVOCandidate=*/nullptr);
3679 }
3680
3681 if (HasDeducedReturnType) {
3682 FunctionDecl *FD = CurLambda->CallOperator;
3683 // If we've already decided this lambda is invalid, e.g. because
3684 // we saw a `return` whose expression had an error, don't keep
3685 // trying to deduce its return type.
3686 if (FD->isInvalidDecl())
3687 return StmtError();
3688 // In C++1y, the return type may involve 'auto'.
3689 // FIXME: Blocks might have a return type of 'auto' explicitly specified.
3690 if (CurCap->ReturnType.isNull())
3691 CurCap->ReturnType = FD->getReturnType();
3692
3693 AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3694 assert(AT && "lost auto type from lambda return type");
3695 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
3696 FD->setInvalidDecl();
3697 // FIXME: preserve the ill-formed return expression.
3698 return StmtError();
3699 }
3700 CurCap->ReturnType = FnRetType = FD->getReturnType();
3701 } else if (CurCap->HasImplicitReturnType) {
3702 // For blocks/lambdas with implicit return types, we check each return
3703 // statement individually, and deduce the common return type when the block
3704 // or lambda is completed.
3705 // FIXME: Fold this into the 'auto' codepath above.
3706 if (RetValExp && !isa<InitListExpr>(Val: RetValExp)) {
3707 ExprResult Result = DefaultFunctionArrayLvalueConversion(E: RetValExp);
3708 if (Result.isInvalid())
3709 return StmtError();
3710 RetValExp = Result.get();
3711
3712 // DR1048: even prior to C++14, we should use the 'auto' deduction rules
3713 // when deducing a return type for a lambda-expression (or by extension
3714 // for a block). These rules differ from the stated C++11 rules only in
3715 // that they remove top-level cv-qualifiers.
3716 if (!CurContext->isDependentContext())
3717 FnRetType = RetValExp->getType().getUnqualifiedType();
3718 else
3719 FnRetType = CurCap->ReturnType = Context.DependentTy;
3720 } else {
3721 if (RetValExp) {
3722 // C++11 [expr.lambda.prim]p4 bans inferring the result from an
3723 // initializer list, because it is not an expression (even
3724 // though we represent it as one). We still deduce 'void'.
3725 Diag(Loc: ReturnLoc, DiagID: diag::err_lambda_return_init_list)
3726 << RetValExp->getSourceRange();
3727 RetValExp = nullptr;
3728 }
3729
3730 FnRetType = Context.VoidTy;
3731 }
3732
3733 // Although we'll properly infer the type of the block once it's completed,
3734 // make sure we provide a return type now for better error recovery.
3735 if (CurCap->ReturnType.isNull())
3736 CurCap->ReturnType = FnRetType;
3737 }
3738 const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
3739
3740 if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap)) {
3741 if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
3742 Diag(Loc: ReturnLoc, DiagID: diag::err_noreturn_has_return_expr)
3743 << diag::FalloffFunctionKind::Block;
3744 return StmtError();
3745 }
3746 } else if (auto *CurRegion = dyn_cast<CapturedRegionScopeInfo>(Val: CurCap)) {
3747 Diag(Loc: ReturnLoc, DiagID: diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3748 return StmtError();
3749 } else {
3750 assert(CurLambda && "unknown kind of captured scope");
3751 if (CurLambda->CallOperator->getType()
3752 ->castAs<FunctionType>()
3753 ->getNoReturnAttr()) {
3754 Diag(Loc: ReturnLoc, DiagID: diag::err_noreturn_has_return_expr)
3755 << diag::FalloffFunctionKind::Lambda;
3756 return StmtError();
3757 }
3758 }
3759
3760 // Otherwise, verify that this result type matches the previous one. We are
3761 // pickier with blocks than for normal functions because we don't have GCC
3762 // compatibility to worry about here.
3763 if (FnRetType->isDependentType()) {
3764 // Delay processing for now. TODO: there are lots of dependent
3765 // types we can conclusively prove aren't void.
3766 } else if (FnRetType->isVoidType()) {
3767 if (isa_and_nonnull<InitListExpr>(Val: RetValExp)) {
3768 Diag(Loc: ReturnLoc, DiagID: diag::err_return_block_has_expr)
3769 << (CurLambda != nullptr);
3770 RetValExp = nullptr;
3771 } else if (RetValExp && !(getLangOpts().CPlusPlus &&
3772 (RetValExp->isTypeDependent() ||
3773 RetValExp->getType()->isVoidType()))) {
3774 if (!getLangOpts().CPlusPlus && RetValExp->getType()->isVoidType())
3775 Diag(Loc: ReturnLoc, DiagID: diag::ext_return_has_void_expr) << "literal" << 2;
3776 else {
3777 Diag(Loc: ReturnLoc, DiagID: diag::err_return_block_has_expr)
3778 << (CurLambda != nullptr);
3779 RetValExp = nullptr;
3780 }
3781 }
3782 } else if (!RetValExp) {
3783 return StmtError(Diag(Loc: ReturnLoc, DiagID: diag::err_block_return_missing_expr));
3784 } else if (!RetValExp->isTypeDependent()) {
3785 // we have a non-void block with an expression, continue checking
3786
3787 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3788 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3789 // function return.
3790
3791 // In C++ the return statement is handled via a copy initialization.
3792 // the C version of which boils down to CheckSingleAssignmentConstraints.
3793 InitializedEntity Entity =
3794 InitializedEntity::InitializeResult(ReturnLoc, Type: FnRetType);
3795 ExprResult Res = PerformMoveOrCopyInitialization(
3796 Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
3797 if (Res.isInvalid()) {
3798 // FIXME: Cleanup temporaries here, anyway?
3799 return StmtError();
3800 }
3801 RetValExp = Res.get();
3802 CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc);
3803 }
3804
3805 if (RetValExp) {
3806 ExprResult ER =
3807 ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3808 if (ER.isInvalid())
3809 return StmtError();
3810 RetValExp = ER.get();
3811 }
3812 auto *Result =
3813 ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
3814
3815 // If we need to check for the named return value optimization,
3816 // or if we need to infer the return type,
3817 // save the return statement in our scope for later processing.
3818 if (CurCap->HasImplicitReturnType || NRVOCandidate)
3819 FunctionScopes.back()->Returns.push_back(Elt: Result);
3820
3821 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3822 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3823
3824 if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap);
3825 CurBlock && CurCap->HasImplicitReturnType && RetValExp &&
3826 RetValExp->containsErrors())
3827 CurBlock->TheDecl->setInvalidDecl();
3828
3829 return Result;
3830}
3831
3832namespace {
3833/// Marks all typedefs in all local classes in a type referenced.
3834///
3835/// In a function like
3836/// auto f() {
3837/// struct S { typedef int a; };
3838/// return S();
3839/// }
3840///
3841/// the local type escapes and could be referenced in some TUs but not in
3842/// others. Pretend that all local typedefs are always referenced, to not warn
3843/// on this. This isn't necessary if f has internal linkage, or the typedef
3844/// is private.
3845class LocalTypedefNameReferencer : public DynamicRecursiveASTVisitor {
3846public:
3847 LocalTypedefNameReferencer(Sema &S) : S(S) {}
3848 bool VisitRecordType(RecordType *RT) override;
3849
3850private:
3851 Sema &S;
3852};
3853bool LocalTypedefNameReferencer::VisitRecordType(RecordType *RT) {
3854 auto *R = dyn_cast<CXXRecordDecl>(Val: RT->getDecl());
3855 if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3856 R->isDependentType())
3857 return true;
3858 for (auto *TmpD : R->decls())
3859 if (auto *T = dyn_cast<TypedefNameDecl>(Val: TmpD))
3860 if (T->getAccess() != AS_private || R->hasFriends())
3861 S.MarkAnyDeclReferenced(Loc: T->getLocation(), D: T, /*OdrUse=*/MightBeOdrUse: false);
3862 return true;
3863}
3864}
3865
3866TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3867 return FD->getTypeSourceInfo()
3868 ->getTypeLoc()
3869 .getAsAdjusted<FunctionProtoTypeLoc>()
3870 .getReturnLoc();
3871}
3872
3873bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3874 SourceLocation ReturnLoc,
3875 Expr *RetExpr, const AutoType *AT) {
3876 // If this is the conversion function for a lambda, we choose to deduce its
3877 // type from the corresponding call operator, not from the synthesized return
3878 // statement within it. See Sema::DeduceReturnType.
3879 if (isLambdaConversionOperator(D: FD))
3880 return false;
3881
3882 if (isa_and_nonnull<InitListExpr>(Val: RetExpr)) {
3883 // If the deduction is for a return statement and the initializer is
3884 // a braced-init-list, the program is ill-formed.
3885 Diag(Loc: RetExpr->getExprLoc(),
3886 DiagID: getCurLambda() ? diag::err_lambda_return_init_list
3887 : diag::err_auto_fn_return_init_list)
3888 << RetExpr->getSourceRange();
3889 return true;
3890 }
3891
3892 if (FD->isDependentContext()) {
3893 // C++1y [dcl.spec.auto]p12:
3894 // Return type deduction [...] occurs when the definition is
3895 // instantiated even if the function body contains a return
3896 // statement with a non-type-dependent operand.
3897 assert(AT->isDeduced() && "should have deduced to dependent type");
3898 return false;
3899 }
3900
3901 TypeLoc OrigResultType = getReturnTypeLoc(FD);
3902 // In the case of a return with no operand, the initializer is considered
3903 // to be void().
3904 CXXScalarValueInitExpr VoidVal(Context.VoidTy, nullptr, SourceLocation());
3905 if (!RetExpr) {
3906 // For a function with a deduced result type to return with omitted
3907 // expression, the result type as written must be 'auto' or
3908 // 'decltype(auto)', possibly cv-qualified or constrained, but not
3909 // ref-qualified.
3910 if (!OrigResultType.getType()->getAs<AutoType>()) {
3911 Diag(Loc: ReturnLoc, DiagID: diag::err_auto_fn_return_void_but_not_auto)
3912 << OrigResultType.getType();
3913 return true;
3914 }
3915 RetExpr = &VoidVal;
3916 }
3917
3918 QualType Deduced = AT->getDeducedType();
3919 {
3920 // Otherwise, [...] deduce a value for U using the rules of template
3921 // argument deduction.
3922 auto RetExprLoc = RetExpr->getExprLoc();
3923 TemplateDeductionInfo Info(RetExprLoc);
3924 SourceLocation TemplateSpecLoc;
3925 if (RetExpr->getType() == Context.OverloadTy) {
3926 auto FindResult = OverloadExpr::find(E: RetExpr);
3927 if (FindResult.Expression)
3928 TemplateSpecLoc = FindResult.Expression->getNameLoc();
3929 }
3930 TemplateSpecCandidateSet FailedTSC(TemplateSpecLoc);
3931 TemplateDeductionResult Res = DeduceAutoType(
3932 AutoTypeLoc: OrigResultType, Initializer: RetExpr, Result&: Deduced, Info, /*DependentDeduction=*/false,
3933 /*IgnoreConstraints=*/false, FailedTSC: &FailedTSC);
3934 if (Res != TemplateDeductionResult::Success && FD->isInvalidDecl())
3935 return true;
3936 switch (Res) {
3937 case TemplateDeductionResult::Success:
3938 break;
3939 case TemplateDeductionResult::AlreadyDiagnosed:
3940 return true;
3941 case TemplateDeductionResult::Inconsistent: {
3942 // If a function with a declared return type that contains a placeholder
3943 // type has multiple return statements, the return type is deduced for
3944 // each return statement. [...] if the type deduced is not the same in
3945 // each deduction, the program is ill-formed.
3946 const LambdaScopeInfo *LambdaSI = getCurLambda();
3947 if (LambdaSI && LambdaSI->HasImplicitReturnType)
3948 Diag(Loc: ReturnLoc, DiagID: diag::err_typecheck_missing_return_type_incompatible)
3949 << Info.SecondArg << Info.FirstArg << true /*IsLambda*/;
3950 else
3951 Diag(Loc: ReturnLoc, DiagID: diag::err_auto_fn_different_deductions)
3952 << (AT->isDecltypeAuto() ? 1 : 0) << Info.SecondArg
3953 << Info.FirstArg;
3954 return true;
3955 }
3956 default:
3957 Diag(Loc: RetExpr->getExprLoc(), DiagID: diag::err_auto_fn_deduction_failure)
3958 << OrigResultType.getType() << RetExpr->getType();
3959 FailedTSC.NoteCandidates(S&: *this, Loc: RetExprLoc);
3960 return true;
3961 }
3962 }
3963
3964 // If a local type is part of the returned type, mark its fields as
3965 // referenced.
3966 LocalTypedefNameReferencer(*this).TraverseType(T: RetExpr->getType());
3967
3968 // CUDA: Kernel function must have 'void' return type.
3969 if (getLangOpts().CUDA && FD->hasAttr<CUDAGlobalAttr>() &&
3970 !Deduced->isVoidType()) {
3971 Diag(Loc: FD->getLocation(), DiagID: diag::err_kern_type_not_void_return)
3972 << FD->getType() << FD->getSourceRange();
3973 return true;
3974 }
3975
3976 if (!FD->isInvalidDecl() && AT->getDeducedType() != Deduced)
3977 // Update all declarations of the function to have the deduced return type.
3978 Context.adjustDeducedFunctionResultType(FD, ResultType: Deduced);
3979
3980 if (!Deduced->isDependentType() && !Deduced->isRecordType() &&
3981 !FD->isFunctionTemplateSpecialization())
3982 diagnoseIgnoredQualifiers(
3983 DiagID: diag::warn_qual_return_type,
3984 Quals: FD->getDeclaredReturnType().getLocalCVRQualifiers(), FallbackLoc: FD->getLocation());
3985 return false;
3986}
3987
3988StmtResult
3989Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3990 Scope *CurScope) {
3991 ExprResult RetVal = RetValExp;
3992 if (RetVal.isInvalid())
3993 return StmtError();
3994
3995 if (getCurScope()->isInOpenACCComputeConstructScope())
3996 return StmtError(
3997 Diag(Loc: ReturnLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3998 << /*return*/ 1 << /*out of */ 0);
3999
4000 // using plain return in a coroutine is not allowed.
4001 FunctionScopeInfo *FSI = getCurFunction();
4002 if (FSI->FirstReturnLoc.isInvalid() && FSI->isCoroutine()) {
4003 assert(FSI->FirstCoroutineStmtLoc.isValid() &&
4004 "first coroutine location not set");
4005 Diag(Loc: ReturnLoc, DiagID: diag::err_return_in_coroutine);
4006 Diag(Loc: FSI->FirstCoroutineStmtLoc, DiagID: diag::note_declared_coroutine_here)
4007 << FSI->getFirstCoroutineStmtKeyword();
4008 }
4009
4010 CheckInvalidBuiltinCountedByRef(E: RetVal.get(),
4011 K: BuiltinCountedByRefKind::ReturnArg);
4012
4013 StmtResult R =
4014 BuildReturnStmt(ReturnLoc, RetValExp: RetVal.get(), /*AllowRecovery=*/true);
4015 if (R.isInvalid() || ExprEvalContexts.back().isDiscardedStatementContext())
4016 return R;
4017
4018 VarDecl *VD =
4019 const_cast<VarDecl *>(cast<ReturnStmt>(Val: R.get())->getNRVOCandidate());
4020
4021 CurScope->updateNRVOCandidate(VD);
4022
4023 CheckJumpOutOfSEHFinallyOrDefer(S&: *this, Loc: ReturnLoc, DestScope: *CurScope->getFnParent(),
4024 DeferJumpKind: diag::DeferJumpKind::Return);
4025
4026 return R;
4027}
4028
4029void Sema::ActOnStartOfDeferStmt(SourceLocation DeferLoc, Scope *CurScope) {
4030 CurrentDefer.emplace_back(Args&: CurScope, Args&: DeferLoc);
4031}
4032
4033void Sema::ActOnDeferStmtError([[maybe_unused]] Scope *CurScope) {
4034 assert(!CurrentDefer.empty() && CurrentDefer.back().first == CurScope);
4035 CurrentDefer.pop_back();
4036}
4037
4038StmtResult Sema::ActOnEndOfDeferStmt(Stmt *Body,
4039 [[maybe_unused]] Scope *CurScope) {
4040 assert(!CurrentDefer.empty() && CurrentDefer.back().first == CurScope);
4041 SourceLocation DeferLoc = CurrentDefer.pop_back_val().second;
4042 DiagnoseEmptyStmtBody(StmtLoc: DeferLoc, Body, DiagID: diag::warn_empty_defer_body);
4043 setFunctionHasBranchProtectedScope();
4044 return DeferStmt::Create(Context, DeferLoc, Body);
4045}
4046
4047static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
4048 const Expr *E) {
4049 if (!E || !S.getLangOpts().CPlusPlus23 || !S.getLangOpts().MSVCCompat)
4050 return false;
4051 const Decl *D = E->getReferencedDeclOfCallee();
4052 if (!D || !S.SourceMgr.isInSystemHeader(Loc: D->getLocation()))
4053 return false;
4054 for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
4055 if (DC->isStdNamespace())
4056 return true;
4057 }
4058 return false;
4059}
4060
4061StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
4062 bool AllowRecovery) {
4063 // Check for unexpanded parameter packs.
4064 if (RetValExp && DiagnoseUnexpandedParameterPack(E: RetValExp))
4065 return StmtError();
4066
4067 // HACK: We suppress simpler implicit move here in msvc compatibility mode
4068 // just as a temporary work around, as the MSVC STL has issues with
4069 // this change.
4070 bool SupressSimplerImplicitMoves =
4071 CheckSimplerImplicitMovesMSVCWorkaround(S: *this, E: RetValExp);
4072 NamedReturnInfo NRInfo = getNamedReturnInfo(
4073 E&: RetValExp, Mode: SupressSimplerImplicitMoves ? SimplerImplicitMoveMode::ForceOff
4074 : SimplerImplicitMoveMode::Normal);
4075
4076 if (isa<CapturingScopeInfo>(Val: getCurFunction()))
4077 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
4078 SupressSimplerImplicitMoves);
4079
4080 QualType FnRetType;
4081 QualType RelatedRetType;
4082 const AttrVec *Attrs = nullptr;
4083 bool isObjCMethod = false;
4084
4085 if (const FunctionDecl *FD = getCurFunctionDecl()) {
4086 FnRetType = FD->getReturnType();
4087 if (FD->hasAttrs())
4088 Attrs = &FD->getAttrs();
4089 if (FD->isNoReturn() && !getCurFunction()->isCoroutine())
4090 Diag(Loc: ReturnLoc, DiagID: diag::warn_noreturn_function_has_return_expr) << FD;
4091 if (FD->isMain() && RetValExp)
4092 if (isa<CXXBoolLiteralExpr>(Val: RetValExp))
4093 Diag(Loc: ReturnLoc, DiagID: diag::warn_main_returns_bool_literal)
4094 << RetValExp->getSourceRange();
4095 if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
4096 if (const auto *RT = dyn_cast<RecordType>(Val: FnRetType.getCanonicalType())) {
4097 if (RT->getDecl()->isOrContainsUnion())
4098 Diag(Loc: RetValExp->getBeginLoc(), DiagID: diag::warn_cmse_nonsecure_union) << 1;
4099 }
4100 }
4101 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
4102 FnRetType = MD->getReturnType();
4103 isObjCMethod = true;
4104 if (MD->hasAttrs())
4105 Attrs = &MD->getAttrs();
4106 if (MD->hasRelatedResultType() && MD->getClassInterface()) {
4107 // In the implementation of a method with a related return type, the
4108 // type used to type-check the validity of return statements within the
4109 // method body is a pointer to the type of the class being implemented.
4110 RelatedRetType = Context.getObjCInterfaceType(Decl: MD->getClassInterface());
4111 RelatedRetType = Context.getObjCObjectPointerType(OIT: RelatedRetType);
4112 }
4113 } else // If we don't have a function/method context, bail.
4114 return StmtError();
4115
4116 if (RetValExp) {
4117 const auto *ATy = dyn_cast<ArrayType>(Val: RetValExp->getType());
4118 if (ATy && ATy->getElementType().isWebAssemblyReferenceType()) {
4119 Diag(Loc: ReturnLoc, DiagID: diag::err_wasm_table_art) << 1;
4120 return StmtError();
4121 }
4122 }
4123
4124 // C++1z: discarded return statements are not considered when deducing a
4125 // return type.
4126 if (ExprEvalContexts.back().isDiscardedStatementContext() &&
4127 FnRetType->getContainedAutoType()) {
4128 if (RetValExp) {
4129 ExprResult ER =
4130 ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4131 if (ER.isInvalid())
4132 return StmtError();
4133 RetValExp = ER.get();
4134 }
4135 return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4136 /* NRVOCandidate=*/nullptr);
4137 }
4138
4139 // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
4140 // deduction.
4141 if (getLangOpts().CPlusPlus14) {
4142 if (AutoType *AT = FnRetType->getContainedAutoType()) {
4143 FunctionDecl *FD = cast<FunctionDecl>(Val: CurContext);
4144 // If we've already decided this function is invalid, e.g. because
4145 // we saw a `return` whose expression had an error, don't keep
4146 // trying to deduce its return type.
4147 // (Some return values may be needlessly wrapped in RecoveryExpr).
4148 if (FD->isInvalidDecl() ||
4149 DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
4150 FD->setInvalidDecl();
4151 if (!AllowRecovery)
4152 return StmtError();
4153 // The deduction failure is diagnosed and marked, try to recover.
4154 if (RetValExp) {
4155 // Wrap return value with a recovery expression of the previous type.
4156 // If no deduction yet, use DependentTy.
4157 auto Recovery = CreateRecoveryExpr(
4158 Begin: RetValExp->getBeginLoc(), End: RetValExp->getEndLoc(), SubExprs: RetValExp,
4159 T: AT->isDeduced() ? FnRetType : QualType());
4160 if (Recovery.isInvalid())
4161 return StmtError();
4162 RetValExp = Recovery.get();
4163 } else {
4164 // Nothing to do: a ReturnStmt with no value is fine recovery.
4165 }
4166 } else {
4167 FnRetType = FD->getReturnType();
4168 }
4169 }
4170 }
4171 const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
4172
4173 bool HasDependentReturnType = FnRetType->isDependentType();
4174
4175 ReturnStmt *Result = nullptr;
4176 if (FnRetType->isVoidType()) {
4177 if (RetValExp) {
4178 if (auto *ILE = dyn_cast<InitListExpr>(Val: RetValExp)) {
4179 // We simply never allow init lists as the return value of void
4180 // functions. This is compatible because this was never allowed before,
4181 // so there's no legacy code to deal with.
4182 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4183 int FunctionKind = 0;
4184 if (isa<ObjCMethodDecl>(Val: CurDecl))
4185 FunctionKind = 1;
4186 else if (isa<CXXConstructorDecl>(Val: CurDecl))
4187 FunctionKind = 2;
4188 else if (isa<CXXDestructorDecl>(Val: CurDecl))
4189 FunctionKind = 3;
4190
4191 Diag(Loc: ReturnLoc, DiagID: diag::err_return_init_list)
4192 << CurDecl << FunctionKind << RetValExp->getSourceRange();
4193
4194 // Preserve the initializers in the AST.
4195 RetValExp = AllowRecovery
4196 ? CreateRecoveryExpr(Begin: ILE->getLBraceLoc(),
4197 End: ILE->getRBraceLoc(), SubExprs: ILE->inits())
4198 .get()
4199 : nullptr;
4200 } else if (!RetValExp->isTypeDependent()) {
4201 // C99 6.8.6.4p1 (ext_ since GCC warns)
4202 unsigned D = diag::ext_return_has_expr;
4203 if (RetValExp->getType()->isVoidType()) {
4204 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4205 if (isa<CXXConstructorDecl>(Val: CurDecl) ||
4206 isa<CXXDestructorDecl>(Val: CurDecl))
4207 D = diag::err_ctor_dtor_returns_void;
4208 else
4209 D = diag::ext_return_has_void_expr;
4210 }
4211 else {
4212 ExprResult Result = RetValExp;
4213 Result = IgnoredValueConversions(E: Result.get());
4214 if (Result.isInvalid())
4215 return StmtError();
4216 RetValExp = Result.get();
4217 RetValExp = ImpCastExprToType(E: RetValExp,
4218 Type: Context.VoidTy, CK: CK_ToVoid).get();
4219 }
4220 // return of void in constructor/destructor is illegal in C++.
4221 if (D == diag::err_ctor_dtor_returns_void) {
4222 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4223 Diag(Loc: ReturnLoc, DiagID: D) << CurDecl << isa<CXXDestructorDecl>(Val: CurDecl)
4224 << RetValExp->getSourceRange();
4225 }
4226 // return (some void expression); is legal in C++ and C2y.
4227 else if (D != diag::ext_return_has_void_expr ||
4228 (!getLangOpts().CPlusPlus && !getLangOpts().C2y)) {
4229 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4230
4231 int FunctionKind = 0;
4232 if (isa<ObjCMethodDecl>(Val: CurDecl))
4233 FunctionKind = 1;
4234 else if (isa<CXXConstructorDecl>(Val: CurDecl))
4235 FunctionKind = 2;
4236 else if (isa<CXXDestructorDecl>(Val: CurDecl))
4237 FunctionKind = 3;
4238
4239 Diag(Loc: ReturnLoc, DiagID: D)
4240 << CurDecl << FunctionKind << RetValExp->getSourceRange();
4241 }
4242 }
4243
4244 if (RetValExp) {
4245 ExprResult ER =
4246 ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4247 if (ER.isInvalid())
4248 return StmtError();
4249 RetValExp = ER.get();
4250 }
4251 }
4252
4253 Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4254 /* NRVOCandidate=*/nullptr);
4255 } else if (!RetValExp && !HasDependentReturnType) {
4256 FunctionDecl *FD = getCurFunctionDecl();
4257
4258 if ((FD && FD->isInvalidDecl()) || FnRetType->containsErrors()) {
4259 // The intended return type might have been "void", so don't warn.
4260 } else if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
4261 // C++11 [stmt.return]p2
4262 Diag(Loc: ReturnLoc, DiagID: diag::err_constexpr_return_missing_expr)
4263 << FD << FD->isConsteval();
4264 FD->setInvalidDecl();
4265 } else {
4266 // C99 6.8.6.4p1 (ext_ since GCC warns)
4267 // C90 6.6.6.4p4
4268 unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
4269 : diag::warn_return_missing_expr;
4270 // Note that at this point one of getCurFunctionDecl() or
4271 // getCurMethodDecl() must be non-null (see above).
4272 assert((getCurFunctionDecl() || getCurMethodDecl()) &&
4273 "Not in a FunctionDecl or ObjCMethodDecl?");
4274 bool IsMethod = FD == nullptr;
4275 const NamedDecl *ND =
4276 IsMethod ? cast<NamedDecl>(Val: getCurMethodDecl()) : cast<NamedDecl>(Val: FD);
4277 Diag(Loc: ReturnLoc, DiagID) << ND << IsMethod;
4278 }
4279
4280 Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, /* RetExpr=*/E: nullptr,
4281 /* NRVOCandidate=*/nullptr);
4282 } else {
4283 assert(RetValExp || HasDependentReturnType);
4284 QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
4285
4286 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
4287 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
4288 // function return.
4289
4290 // In C++ the return statement is handled via a copy initialization,
4291 // the C version of which boils down to CheckSingleAssignmentConstraints.
4292 if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
4293 // we have a non-void function with an expression, continue checking
4294 InitializedEntity Entity =
4295 InitializedEntity::InitializeResult(ReturnLoc, Type: RetType);
4296 ExprResult Res = PerformMoveOrCopyInitialization(
4297 Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
4298 if (Res.isInvalid() && AllowRecovery)
4299 Res = CreateRecoveryExpr(Begin: RetValExp->getBeginLoc(),
4300 End: RetValExp->getEndLoc(), SubExprs: RetValExp, T: RetType);
4301 if (Res.isInvalid()) {
4302 // FIXME: Clean up temporaries here anyway?
4303 return StmtError();
4304 }
4305 RetValExp = Res.getAs<Expr>();
4306
4307 // A returned HLSL matrix may need its layout reconciled with the
4308 // function's row_major/column_major return type.
4309 if (getLangOpts().HLSL && RetValExp && RetType->isMatrixType())
4310 HLSL().propagateContextualMatrixLayout(E: RetValExp, DestType: RetType);
4311
4312 // If we have a related result type, we need to implicitly
4313 // convert back to the formal result type. We can't pretend to
4314 // initialize the result again --- we might end double-retaining
4315 // --- so instead we initialize a notional temporary.
4316 if (!RelatedRetType.isNull()) {
4317 Entity = InitializedEntity::InitializeRelatedResult(MD: getCurMethodDecl(),
4318 Type: FnRetType);
4319 Res = PerformCopyInitialization(Entity, EqualLoc: ReturnLoc, Init: RetValExp);
4320 if (Res.isInvalid()) {
4321 // FIXME: Clean up temporaries here anyway?
4322 return StmtError();
4323 }
4324 RetValExp = Res.getAs<Expr>();
4325 }
4326
4327 CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc, isObjCMethod, Attrs,
4328 FD: getCurFunctionDecl());
4329 }
4330
4331 if (RetValExp) {
4332 ExprResult ER =
4333 ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4334 if (ER.isInvalid())
4335 return StmtError();
4336 RetValExp = ER.get();
4337 }
4338 Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
4339 }
4340
4341 // If we need to check for the named return value optimization, save the
4342 // return statement in our scope for later processing.
4343 if (Result->getNRVOCandidate())
4344 FunctionScopes.back()->Returns.push_back(Elt: Result);
4345
4346 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
4347 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
4348
4349 return Result;
4350}
4351
4352StmtResult
4353Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
4354 Stmt *HandlerBlock) {
4355 // There's nothing to test that ActOnExceptionDecl didn't already test.
4356 return new (Context)
4357 CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(Val: ExDecl), HandlerBlock);
4358}
4359
4360namespace {
4361class CatchHandlerType {
4362 QualType QT;
4363 LLVM_PREFERRED_TYPE(bool)
4364 unsigned IsPointer : 1;
4365
4366 friend struct llvm::DenseMapInfo<CatchHandlerType>;
4367
4368public:
4369 /// Used when creating a CatchHandlerType from a handler type; will determine
4370 /// whether the type is a pointer or reference and will strip off the top
4371 /// level pointer and cv-qualifiers.
4372 CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
4373 if (QT->isPointerType())
4374 IsPointer = true;
4375
4376 QT = QT.getUnqualifiedType();
4377 if (IsPointer || QT->isReferenceType())
4378 QT = QT->getPointeeType();
4379 }
4380
4381 /// Used when creating a CatchHandlerType from a base class type; pretends the
4382 /// type passed in had the pointer qualifier, does not need to get an
4383 /// unqualified type.
4384 CatchHandlerType(QualType QT, bool IsPointer)
4385 : QT(QT), IsPointer(IsPointer) {}
4386
4387 QualType underlying() const { return QT; }
4388 bool isPointer() const { return IsPointer; }
4389
4390 friend bool operator==(const CatchHandlerType &LHS,
4391 const CatchHandlerType &RHS) {
4392 // If the pointer qualification does not match, we can return early.
4393 if (LHS.IsPointer != RHS.IsPointer)
4394 return false;
4395 // Otherwise, check the underlying type without cv-qualifiers.
4396 return LHS.QT == RHS.QT;
4397 }
4398};
4399} // namespace
4400
4401namespace llvm {
4402template <> struct DenseMapInfo<CatchHandlerType> {
4403 static unsigned getHashValue(const CatchHandlerType &Base) {
4404 return DenseMapInfo<QualType>::getHashValue(Val: Base.underlying());
4405 }
4406
4407 static bool isEqual(const CatchHandlerType &LHS,
4408 const CatchHandlerType &RHS) {
4409 return LHS == RHS;
4410 }
4411};
4412}
4413
4414namespace {
4415class CatchTypePublicBases {
4416 const llvm::DenseMap<QualType, CXXCatchStmt *> &TypesToCheck;
4417
4418 CXXCatchStmt *FoundHandler;
4419 QualType FoundHandlerType;
4420 QualType TestAgainstType;
4421
4422public:
4423 CatchTypePublicBases(const llvm::DenseMap<QualType, CXXCatchStmt *> &T,
4424 QualType QT)
4425 : TypesToCheck(T), FoundHandler(nullptr), TestAgainstType(QT) {}
4426
4427 CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
4428 QualType getFoundHandlerType() const { return FoundHandlerType; }
4429
4430 bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
4431 if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
4432 QualType Check = S->getType().getCanonicalType();
4433 const auto &M = TypesToCheck;
4434 auto I = M.find(Val: Check);
4435 if (I != M.end()) {
4436 // We're pretty sure we found what we need to find. However, we still
4437 // need to make sure that we properly compare for pointers and
4438 // references, to handle cases like:
4439 //
4440 // } catch (Base *b) {
4441 // } catch (Derived &d) {
4442 // }
4443 //
4444 // where there is a qualification mismatch that disqualifies this
4445 // handler as a potential problem.
4446 if (I->second->getCaughtType()->isPointerType() ==
4447 TestAgainstType->isPointerType()) {
4448 FoundHandler = I->second;
4449 FoundHandlerType = Check;
4450 return true;
4451 }
4452 }
4453 }
4454 return false;
4455 }
4456};
4457}
4458
4459StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
4460 ArrayRef<Stmt *> Handlers) {
4461 const llvm::Triple &T = Context.getTargetInfo().getTriple();
4462 const bool IsOpenMPGPUTarget =
4463 getLangOpts().OpenMPIsTargetDevice && T.isGPU();
4464
4465 DiagnoseExceptionUse(Loc: TryLoc, /* IsTry= */ true);
4466
4467 // In OpenMP target regions, we assume that catch is never reached on GPU
4468 // targets.
4469 if (IsOpenMPGPUTarget)
4470 targetDiag(Loc: TryLoc, DiagID: diag::warn_try_not_valid_on_target) << T.str();
4471
4472 // Exceptions aren't allowed in CUDA device code.
4473 if (getLangOpts().CUDA)
4474 CUDA().DiagIfDeviceCode(Loc: TryLoc, DiagID: diag::err_cuda_device_exceptions)
4475 << "try" << CUDA().CurrentTarget();
4476
4477 if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
4478 Diag(Loc: TryLoc, DiagID: diag::err_omp_simd_region_cannot_use_stmt) << "try";
4479
4480 sema::FunctionScopeInfo *FSI = getCurFunction();
4481
4482 // C++ try is incompatible with SEH __try.
4483 if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
4484 Diag(Loc: TryLoc, DiagID: diag::err_mixing_cxx_try_seh_try) << 0;
4485 Diag(Loc: FSI->FirstSEHTryLoc, DiagID: diag::note_conflicting_try_here) << "'__try'";
4486 }
4487
4488 const unsigned NumHandlers = Handlers.size();
4489 assert(!Handlers.empty() &&
4490 "The parser shouldn't call this if there are no handlers.");
4491
4492 llvm::DenseMap<QualType, CXXCatchStmt *> HandledBaseTypes;
4493 llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
4494 for (unsigned i = 0; i < NumHandlers; ++i) {
4495 CXXCatchStmt *H = cast<CXXCatchStmt>(Val: Handlers[i]);
4496
4497 // Diagnose when the handler is a catch-all handler, but it isn't the last
4498 // handler for the try block. [except.handle]p5. Also, skip exception
4499 // declarations that are invalid, since we can't usefully report on them.
4500 if (!H->getExceptionDecl()) {
4501 if (i < NumHandlers - 1)
4502 return StmtError(Diag(Loc: H->getBeginLoc(), DiagID: diag::err_early_catch_all));
4503 continue;
4504 } else if (H->getExceptionDecl()->isInvalidDecl())
4505 continue;
4506
4507 // Walk the type hierarchy to diagnose when this type has already been
4508 // handled (duplication), or cannot be handled (derivation inversion). We
4509 // ignore top-level cv-qualifiers, per [except.handle]p3
4510 CatchHandlerType HandlerCHT = H->getCaughtType().getCanonicalType();
4511
4512 // We can ignore whether the type is a reference or a pointer; we need the
4513 // underlying declaration type in order to get at the underlying record
4514 // decl, if there is one.
4515 QualType Underlying = HandlerCHT.underlying();
4516 if (auto *RD = Underlying->getAsCXXRecordDecl()) {
4517 if (!RD->hasDefinition())
4518 continue;
4519 // Check that none of the public, unambiguous base classes are in the
4520 // map ([except.handle]p1). Give the base classes the same pointer
4521 // qualification as the original type we are basing off of. This allows
4522 // comparison against the handler type using the same top-level pointer
4523 // as the original type.
4524 CXXBasePaths Paths;
4525 Paths.setOrigin(RD);
4526 CatchTypePublicBases CTPB(HandledBaseTypes,
4527 H->getCaughtType().getCanonicalType());
4528 if (RD->lookupInBases(BaseMatches: CTPB, Paths)) {
4529 const CXXCatchStmt *Problem = CTPB.getFoundHandler();
4530 if (!Paths.isAmbiguous(
4531 BaseType: CanQualType::CreateUnsafe(Other: CTPB.getFoundHandlerType()))) {
4532 Diag(Loc: H->getExceptionDecl()->getTypeSpecStartLoc(),
4533 DiagID: diag::warn_exception_caught_by_earlier_handler)
4534 << H->getCaughtType();
4535 Diag(Loc: Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4536 DiagID: diag::note_previous_exception_handler)
4537 << Problem->getCaughtType();
4538 }
4539 }
4540 // Strip the qualifiers here because we're going to be comparing this
4541 // type to the base type specifiers of a class, which are ignored in a
4542 // base specifier per [class.derived.general]p2.
4543 HandledBaseTypes[Underlying.getUnqualifiedType()] = H;
4544 }
4545
4546 // Add the type the list of ones we have handled; diagnose if we've already
4547 // handled it.
4548 auto R = HandledTypes.insert(
4549 KV: std::make_pair(x: H->getCaughtType().getCanonicalType(), y&: H));
4550 if (!R.second) {
4551 const CXXCatchStmt *Problem = R.first->second;
4552 Diag(Loc: H->getExceptionDecl()->getTypeSpecStartLoc(),
4553 DiagID: diag::warn_exception_caught_by_earlier_handler)
4554 << H->getCaughtType();
4555 Diag(Loc: Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4556 DiagID: diag::note_previous_exception_handler)
4557 << Problem->getCaughtType();
4558 }
4559 }
4560
4561 FSI->setHasCXXTry(TryLoc);
4562
4563 return CXXTryStmt::Create(C: Context, tryLoc: TryLoc, tryBlock: cast<CompoundStmt>(Val: TryBlock),
4564 handlers: Handlers);
4565}
4566
4567void Sema::DiagnoseExceptionUse(SourceLocation Loc, bool IsTry) {
4568 const llvm::Triple &T = Context.getTargetInfo().getTriple();
4569 const bool IsOpenMPGPUTarget =
4570 getLangOpts().OpenMPIsTargetDevice && T.isGPU();
4571
4572 // Don't report an error if 'try' is used in system headers or in an OpenMP
4573 // target region compiled for a GPU architecture.
4574 if (IsOpenMPGPUTarget || getLangOpts().CUDA)
4575 // Delay error emission for the OpenMP device code.
4576 return;
4577
4578 if (!getLangOpts().CXXExceptions &&
4579 !getSourceManager().isInSystemHeader(Loc) &&
4580 !CurContext->isDependentContext())
4581 targetDiag(Loc, DiagID: diag::err_exceptions_disabled) << (IsTry ? "try" : "throw");
4582}
4583
4584StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
4585 Stmt *TryBlock, Stmt *Handler) {
4586 assert(TryBlock && Handler);
4587
4588 sema::FunctionScopeInfo *FSI = getCurFunction();
4589
4590 // SEH __try is incompatible with C++ try. Borland appears to support this,
4591 // however.
4592 if (!getLangOpts().Borland) {
4593 if (FSI->FirstCXXOrObjCTryLoc.isValid()) {
4594 Diag(Loc: TryLoc, DiagID: diag::err_mixing_cxx_try_seh_try) << FSI->FirstTryType;
4595 Diag(Loc: FSI->FirstCXXOrObjCTryLoc, DiagID: diag::note_conflicting_try_here)
4596 << (FSI->FirstTryType == sema::FunctionScopeInfo::TryLocIsCXX
4597 ? "'try'"
4598 : "'@try'");
4599 }
4600 }
4601
4602 FSI->setHasSEHTry(TryLoc);
4603
4604 // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
4605 // track if they use SEH.
4606 DeclContext *DC = CurContext;
4607 while (DC && !DC->isFunctionOrMethod())
4608 DC = DC->getParent();
4609 FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Val: DC);
4610 if (FD)
4611 FD->setUsesSEHTry(true);
4612 else
4613 Diag(Loc: TryLoc, DiagID: diag::err_seh_try_outside_functions);
4614
4615 // Reject __try on unsupported targets.
4616 if (!Context.getTargetInfo().isSEHTrySupported())
4617 Diag(Loc: TryLoc, DiagID: diag::err_seh_try_unsupported);
4618
4619 return SEHTryStmt::Create(C: Context, isCXXTry: IsCXXTry, TryLoc, TryBlock, Handler);
4620}
4621
4622StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
4623 Stmt *Block) {
4624 assert(FilterExpr && Block);
4625 QualType FTy = FilterExpr->getType();
4626 if (!FTy->isIntegerType() && !FTy->isDependentType()) {
4627 return StmtError(
4628 Diag(Loc: FilterExpr->getExprLoc(), DiagID: diag::err_filter_expression_integral)
4629 << FTy);
4630 }
4631 return SEHExceptStmt::Create(C: Context, ExceptLoc: Loc, FilterExpr, Block);
4632}
4633
4634void Sema::ActOnStartSEHFinallyBlock() {
4635 CurrentSEHFinally.push_back(Elt: CurScope);
4636}
4637
4638void Sema::ActOnAbortSEHFinallyBlock() {
4639 CurrentSEHFinally.pop_back();
4640}
4641
4642StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
4643 assert(Block);
4644 CurrentSEHFinally.pop_back();
4645 return SEHFinallyStmt::Create(C: Context, FinallyLoc: Loc, Block);
4646}
4647
4648StmtResult
4649Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
4650 Scope *SEHTryParent = CurScope;
4651 while (SEHTryParent && !SEHTryParent->isSEHTryScope())
4652 SEHTryParent = SEHTryParent->getParent();
4653 if (!SEHTryParent)
4654 return StmtError(Diag(Loc, DiagID: diag::err_ms___leave_not_in___try));
4655 CheckJumpOutOfSEHFinallyOrDefer(S&: *this, Loc, DestScope: *SEHTryParent,
4656 DeferJumpKind: diag::DeferJumpKind::SEHLeave);
4657
4658 return new (Context) SEHLeaveStmt(Loc);
4659}
4660
4661StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
4662 bool IsIfExists,
4663 NestedNameSpecifierLoc QualifierLoc,
4664 DeclarationNameInfo NameInfo,
4665 Stmt *Nested)
4666{
4667 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
4668 QualifierLoc, NameInfo,
4669 cast<CompoundStmt>(Val: Nested));
4670}
4671
4672
4673StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4674 bool IsIfExists,
4675 CXXScopeSpec &SS,
4676 UnqualifiedId &Name,
4677 Stmt *Nested) {
4678 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4679 QualifierLoc: SS.getWithLocInContext(Context),
4680 NameInfo: GetNameFromUnqualifiedId(Name),
4681 Nested);
4682}
4683
4684RecordDecl*
4685Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4686 unsigned NumParams) {
4687 DeclContext *DC = CurContext;
4688 while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4689 DC = DC->getParent();
4690
4691 RecordDecl *RD = nullptr;
4692 if (getLangOpts().CPlusPlus)
4693 RD = CXXRecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4694 /*Id=*/nullptr);
4695 else
4696 RD = RecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4697 /*Id=*/nullptr);
4698
4699 RD->setCapturedRecord();
4700 DC->addDecl(D: RD);
4701 RD->setImplicit();
4702 RD->startDefinition();
4703
4704 assert(NumParams > 0 && "CapturedStmt requires context parameter");
4705 CD = CapturedDecl::Create(C&: Context, DC: CurContext, NumParams);
4706 DC->addDecl(D: CD);
4707 return RD;
4708}
4709
4710static bool
4711buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
4712 SmallVectorImpl<CapturedStmt::Capture> &Captures,
4713 SmallVectorImpl<Expr *> &CaptureInits) {
4714 for (const sema::Capture &Cap : RSI->Captures) {
4715 if (Cap.isInvalid())
4716 continue;
4717
4718 // Form the initializer for the capture.
4719 ExprResult Init = S.BuildCaptureInit(Capture: Cap, ImplicitCaptureLoc: Cap.getLocation(),
4720 IsOpenMPMapping: RSI->CapRegionKind == CR_OpenMP);
4721
4722 // FIXME: Bail out now if the capture is not used and the initializer has
4723 // no side-effects.
4724
4725 // Create a field for this capture.
4726 FieldDecl *Field = S.BuildCaptureField(RD: RSI->TheRecordDecl, Capture: Cap);
4727
4728 // Add the capture to our list of captures.
4729 if (Cap.isThisCapture()) {
4730 Captures.push_back(Elt: CapturedStmt::Capture(Cap.getLocation(),
4731 CapturedStmt::VCK_This));
4732 } else if (Cap.isVLATypeCapture()) {
4733 Captures.push_back(
4734 Elt: CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
4735 } else {
4736 assert(Cap.isVariableCapture() && "unknown kind of capture");
4737
4738 if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
4739 S.OpenMP().setOpenMPCaptureKind(FD: Field, D: Cap.getVariable(),
4740 Level: RSI->OpenMPLevel);
4741
4742 Captures.push_back(Elt: CapturedStmt::Capture(
4743 Cap.getLocation(),
4744 Cap.isReferenceCapture() ? CapturedStmt::VCK_ByRef
4745 : CapturedStmt::VCK_ByCopy,
4746 cast<VarDecl>(Val: Cap.getVariable())));
4747 }
4748 CaptureInits.push_back(Elt: Init.get());
4749 }
4750 return false;
4751}
4752
4753static std::optional<int>
4754isOpenMPCapturedRegionInArmSMEFunction(Sema const &S, CapturedRegionKind Kind) {
4755 if (!S.getLangOpts().OpenMP || Kind != CR_OpenMP)
4756 return {};
4757 if (const FunctionDecl *FD = S.getCurFunctionDecl(/*AllowLambda=*/true)) {
4758 if (IsArmStreamingFunction(FD, /*IncludeLocallyStreaming=*/true))
4759 return /* in streaming functions */ 0;
4760 if (hasArmZAState(FD))
4761 return /* in functions with ZA state */ 1;
4762 if (hasArmZT0State(FD))
4763 return /* in fuctions with ZT0 state */ 2;
4764 }
4765 return {};
4766}
4767
4768void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4769 CapturedRegionKind Kind,
4770 unsigned NumParams) {
4771 if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(S: *this, Kind))
4772 Diag(Loc, DiagID: diag::err_sme_openmp_captured_region) << *ErrorIndex;
4773
4774 CapturedDecl *CD = nullptr;
4775 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4776
4777 // Build the context parameter
4778 DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4779 IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4780 CanQualType ParamType =
4781 Context.getPointerType(T: Context.getCanonicalTagType(TD: RD));
4782 auto *Param =
4783 ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4784 ParamKind: ImplicitParamKind::CapturedContext);
4785 DC->addDecl(D: Param);
4786
4787 CD->setContextParam(i: 0, P: Param);
4788
4789 // Enter the capturing scope for this captured region.
4790 PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind);
4791
4792 if (CurScope)
4793 PushDeclContext(S: CurScope, DC: CD);
4794 else
4795 CurContext = CD;
4796
4797 PushExpressionEvaluationContext(
4798 NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4799 ExprEvalContexts.back().InImmediateEscalatingFunctionContext = false;
4800}
4801
4802void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4803 CapturedRegionKind Kind,
4804 ArrayRef<CapturedParamNameType> Params,
4805 unsigned OpenMPCaptureLevel) {
4806 if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(S: *this, Kind))
4807 Diag(Loc, DiagID: diag::err_sme_openmp_captured_region) << *ErrorIndex;
4808
4809 CapturedDecl *CD = nullptr;
4810 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams: Params.size());
4811
4812 // Build the context parameter
4813 DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4814 bool ContextIsFound = false;
4815 unsigned ParamNum = 0;
4816 for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4817 E = Params.end();
4818 I != E; ++I, ++ParamNum) {
4819 if (I->second.isNull()) {
4820 assert(!ContextIsFound &&
4821 "null type has been found already for '__context' parameter");
4822 IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4823 QualType ParamType =
4824 Context.getPointerType(T: Context.getCanonicalTagType(TD: RD))
4825 .withConst()
4826 .withRestrict();
4827 auto *Param =
4828 ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4829 ParamKind: ImplicitParamKind::CapturedContext);
4830 DC->addDecl(D: Param);
4831 CD->setContextParam(i: ParamNum, P: Param);
4832 ContextIsFound = true;
4833 } else {
4834 IdentifierInfo *ParamName = &Context.Idents.get(Name: I->first);
4835 auto *Param =
4836 ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: I->second,
4837 ParamKind: ImplicitParamKind::CapturedContext);
4838 DC->addDecl(D: Param);
4839 CD->setParam(i: ParamNum, P: Param);
4840 }
4841 }
4842 assert(ContextIsFound && "no null type for '__context' parameter");
4843 if (!ContextIsFound) {
4844 // Add __context implicitly if it is not specified.
4845 IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4846 CanQualType ParamType =
4847 Context.getPointerType(T: Context.getCanonicalTagType(TD: RD));
4848 auto *Param =
4849 ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4850 ParamKind: ImplicitParamKind::CapturedContext);
4851 DC->addDecl(D: Param);
4852 CD->setContextParam(i: ParamNum, P: Param);
4853 }
4854 // Enter the capturing scope for this captured region.
4855 PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind, OpenMPCaptureLevel);
4856
4857 if (CurScope)
4858 PushDeclContext(S: CurScope, DC: CD);
4859 else
4860 CurContext = CD;
4861
4862 PushExpressionEvaluationContext(
4863 NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4864}
4865
4866void Sema::ActOnCapturedRegionError() {
4867 DiscardCleanupsInEvaluationContext();
4868 PopExpressionEvaluationContext();
4869 PopDeclContext();
4870 PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4871 CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4872
4873 RecordDecl *Record = RSI->TheRecordDecl;
4874 Record->setInvalidDecl();
4875
4876 SmallVector<Decl*, 4> Fields(Record->fields());
4877 ActOnFields(/*Scope=*/S: nullptr, RecLoc: Record->getLocation(), TagDecl: Record, Fields,
4878 LBrac: SourceLocation(), RBrac: SourceLocation(), AttrList: ParsedAttributesView());
4879}
4880
4881StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4882 // Leave the captured scope before we start creating captures in the
4883 // enclosing scope.
4884 DiscardCleanupsInEvaluationContext();
4885 PopExpressionEvaluationContext();
4886 PopDeclContext();
4887 PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4888 CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4889
4890 SmallVector<CapturedStmt::Capture, 4> Captures;
4891 SmallVector<Expr *, 4> CaptureInits;
4892 if (buildCapturedStmtCaptureList(S&: *this, RSI, Captures, CaptureInits))
4893 return StmtError();
4894
4895 CapturedDecl *CD = RSI->TheCapturedDecl;
4896 RecordDecl *RD = RSI->TheRecordDecl;
4897
4898 CapturedStmt *Res = CapturedStmt::Create(
4899 Context: getASTContext(), S, Kind: static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4900 Captures, CaptureInits, CD, RD);
4901
4902 CD->setBody(Res->getCapturedStmt());
4903 RD->completeDefinition();
4904
4905 return Res;
4906}
4907