1 //===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements semantic analysis for statements.
12 //===----------------------------------------------------------------------===//
14 #include "clang/Sema/SemaInternal.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/ASTDiagnostic.h"
17 #include "clang/AST/ASTLambda.h"
18 #include "clang/AST/CharUnits.h"
19 #include "clang/AST/CXXInheritance.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/EvaluatedExprVisitor.h"
22 #include "clang/AST/ExprCXX.h"
23 #include "clang/AST/ExprObjC.h"
24 #include "clang/AST/RecursiveASTVisitor.h"
25 #include "clang/AST/StmtCXX.h"
26 #include "clang/AST/StmtObjC.h"
27 #include "clang/AST/TypeLoc.h"
28 #include "clang/AST/TypeOrdering.h"
29 #include "clang/Basic/TargetInfo.h"
30 #include "clang/Lex/Preprocessor.h"
31 #include "clang/Sema/Initialization.h"
32 #include "clang/Sema/Lookup.h"
33 #include "clang/Sema/Scope.h"
34 #include "clang/Sema/ScopeInfo.h"
35 #include "llvm/ADT/ArrayRef.h"
36 #include "llvm/ADT/DenseMap.h"
37 #include "llvm/ADT/STLExtras.h"
38 #include "llvm/ADT/SmallPtrSet.h"
39 #include "llvm/ADT/SmallString.h"
40 #include "llvm/ADT/SmallVector.h"
42 using namespace clang;
45 StmtResult Sema::ActOnExprStmt(ExprResult FE) {
49 FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(),
50 /*DiscardedValue*/ true);
54 // C99 6.8.3p2: The expression in an expression statement is evaluated as a
55 // void expression for its side effects. Conversion to void allows any
56 // operand, even incomplete types.
58 // Same thing in for stmt first clause (when expr) and third clause.
59 return StmtResult(FE.getAs<Stmt>());
63 StmtResult Sema::ActOnExprStmtError() {
64 DiscardCleanupsInEvaluationContext();
68 StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
69 bool HasLeadingEmptyMacro) {
70 return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
73 StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
74 SourceLocation EndLoc) {
75 DeclGroupRef DG = dg.get();
77 // If we have an invalid decl, just return an error.
78 if (DG.isNull()) return StmtError();
80 return new (Context) DeclStmt(DG, StartLoc, EndLoc);
83 void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
84 DeclGroupRef DG = dg.get();
86 // If we don't have a declaration, or we have an invalid declaration,
88 if (DG.isNull() || !DG.isSingleDecl())
91 Decl *decl = DG.getSingleDecl();
92 if (!decl || decl->isInvalidDecl())
95 // Only variable declarations are permitted.
96 VarDecl *var = dyn_cast<VarDecl>(decl);
98 Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
99 decl->setInvalidDecl();
103 // foreach variables are never actually initialized in the way that
104 // the parser came up with.
105 var->setInit(nullptr);
107 // In ARC, we don't need to retain the iteration variable of a fast
108 // enumeration loop. Rather than actually trying to catch that
109 // during declaration processing, we remove the consequences here.
110 if (getLangOpts().ObjCAutoRefCount) {
111 QualType type = var->getType();
113 // Only do this if we inferred the lifetime. Inferred lifetime
114 // will show up as a local qualifier because explicit lifetime
115 // should have shown up as an AttributedType instead.
116 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
117 // Add 'const' and mark the variable as pseudo-strong.
118 var->setType(type.withConst());
119 var->setARCPseudoStrong(true);
124 /// \brief Diagnose unused comparisons, both builtin and overloaded operators.
125 /// For '==' and '!=', suggest fixits for '=' or '|='.
127 /// Adding a cast to void (or other expression wrappers) will prevent the
128 /// warning from firing.
129 static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
132 enum { Equality, Inequality, Relational, ThreeWay } Kind;
134 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
135 if (!Op->isComparisonOp())
138 if (Op->getOpcode() == BO_EQ)
140 else if (Op->getOpcode() == BO_NE)
142 else if (Op->getOpcode() == BO_Cmp)
145 assert(Op->isRelationalOp());
148 Loc = Op->getOperatorLoc();
149 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
150 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
151 switch (Op->getOperator()) {
155 case OO_ExclaimEqual:
160 case OO_GreaterEqual:
171 Loc = Op->getOperatorLoc();
172 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
174 // Not a typo-prone comparison.
178 // Suppress warnings when the operator, suspicious as it may be, comes from
179 // a macro expansion.
180 if (S.SourceMgr.isMacroBodyExpansion(Loc))
183 S.Diag(Loc, diag::warn_unused_comparison)
184 << (unsigned)Kind << E->getSourceRange();
186 // If the LHS is a plausible entity to assign to, provide a fixit hint to
187 // correct common typos.
189 if (Kind == Inequality)
190 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
191 << FixItHint::CreateReplacement(Loc, "|=");
192 else if (Kind == Equality)
193 S.Diag(Loc, diag::note_equality_comparison_to_assign)
194 << FixItHint::CreateReplacement(Loc, "=");
200 void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
201 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
202 return DiagnoseUnusedExprResult(Label->getSubStmt());
204 const Expr *E = dyn_cast_or_null<Expr>(S);
208 // If we are in an unevaluated expression context, then there can be no unused
209 // results because the results aren't expected to be used in the first place.
210 if (isUnevaluatedContext())
213 SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
214 // In most cases, we don't want to warn if the expression is written in a
215 // macro body, or if the macro comes from a system header. If the offending
216 // expression is a call to a function with the warn_unused_result attribute,
217 // we warn no matter the location. Because of the order in which the various
218 // checks need to happen, we factor out the macro-related test here.
219 bool ShouldSuppress =
220 SourceMgr.isMacroBodyExpansion(ExprLoc) ||
221 SourceMgr.isInSystemMacro(ExprLoc);
223 const Expr *WarnExpr;
226 if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
229 // If this is a GNU statement expression expanded from a macro, it is probably
230 // unused because it is a function-like macro that can be used as either an
231 // expression or statement. Don't warn, because it is almost certainly a
233 if (isa<StmtExpr>(E) && Loc.isMacroID())
236 // Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
237 // That macro is frequently used to suppress "unused parameter" warnings,
238 // but its implementation makes clang's -Wunused-value fire. Prevent this.
239 if (isa<ParenExpr>(E->IgnoreImpCasts()) && Loc.isMacroID()) {
240 SourceLocation SpellLoc = Loc;
241 if (findMacroSpelling(SpellLoc, "UNREFERENCED_PARAMETER"))
245 // Okay, we have an unused result. Depending on what the base expression is,
246 // we might want to make a more specific diagnostic. Check for one of these
248 unsigned DiagID = diag::warn_unused_expr;
249 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
250 E = Temps->getSubExpr();
251 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
252 E = TempExpr->getSubExpr();
254 if (DiagnoseUnusedComparison(*this, E))
258 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
259 if (E->getType()->isVoidType())
262 // If the callee has attribute pure, const, or warn_unused_result, warn with
263 // a more specific message to make it clear what is happening. If the call
264 // is written in a macro body, only warn if it has the warn_unused_result
266 if (const Decl *FD = CE->getCalleeDecl()) {
267 if (const Attr *A = isa<FunctionDecl>(FD)
268 ? cast<FunctionDecl>(FD)->getUnusedResultAttr()
269 : FD->getAttr<WarnUnusedResultAttr>()) {
270 Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
275 if (FD->hasAttr<PureAttr>()) {
276 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
279 if (FD->hasAttr<ConstAttr>()) {
280 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
284 } else if (ShouldSuppress)
287 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
288 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
289 Diag(Loc, diag::err_arc_unused_init_message) << R1;
292 const ObjCMethodDecl *MD = ME->getMethodDecl();
294 if (const auto *A = MD->getAttr<WarnUnusedResultAttr>()) {
295 Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
299 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
300 const Expr *Source = POE->getSyntacticForm();
301 if (isa<ObjCSubscriptRefExpr>(Source))
302 DiagID = diag::warn_unused_container_subscript_expr;
304 DiagID = diag::warn_unused_property_expr;
305 } else if (const CXXFunctionalCastExpr *FC
306 = dyn_cast<CXXFunctionalCastExpr>(E)) {
307 const Expr *E = FC->getSubExpr();
308 if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(E))
309 E = TE->getSubExpr();
310 if (isa<CXXTemporaryObjectExpr>(E))
312 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E))
313 if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
314 if (!RD->getAttr<WarnUnusedAttr>())
317 // Diagnose "(void*) blah" as a typo for "(void) blah".
318 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
319 TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
320 QualType T = TI->getType();
322 // We really do want to use the non-canonical type here.
323 if (T == Context.VoidPtrTy) {
324 PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
326 Diag(Loc, diag::warn_unused_voidptr)
327 << FixItHint::CreateRemoval(TL.getStarLoc());
332 if (E->isGLValue() && E->getType().isVolatileQualified()) {
333 Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
337 DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
340 void Sema::ActOnStartOfCompoundStmt() {
344 void Sema::ActOnFinishOfCompoundStmt() {
348 sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
349 return getCurFunction()->CompoundScopes.back();
352 StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
353 ArrayRef<Stmt *> Elts, bool isStmtExpr) {
354 const unsigned NumElts = Elts.size();
356 // If we're in C89 mode, check that we don't have any decls after stmts. If
357 // so, emit an extension diagnostic.
358 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
359 // Note that __extension__ can be around a decl.
361 // Skip over all declarations.
362 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
365 // We found the end of the list or a statement. Scan for another declstmt.
366 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
370 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
371 Diag(D->getLocation(), diag::ext_mixed_decls_code);
374 // Warn about unused expressions in statements.
375 for (unsigned i = 0; i != NumElts; ++i) {
376 // Ignore statements that are last in a statement expression.
377 if (isStmtExpr && i == NumElts - 1)
380 DiagnoseUnusedExprResult(Elts[i]);
383 // Check for suspicious empty body (null statement) in `for' and `while'
384 // statements. Don't do anything for template instantiations, this just adds
386 if (NumElts != 0 && !CurrentInstantiationScope &&
387 getCurCompoundScope().HasEmptyLoopBodies) {
388 for (unsigned i = 0; i != NumElts - 1; ++i)
389 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
392 return CompoundStmt::Create(Context, Elts, L, R);
396 Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
397 SourceLocation DotDotDotLoc, Expr *RHSVal,
398 SourceLocation ColonLoc) {
399 assert(LHSVal && "missing expression in case statement");
401 if (getCurFunction()->SwitchStack.empty()) {
402 Diag(CaseLoc, diag::err_case_not_in_switch);
407 CorrectDelayedTyposInExpr(LHSVal, [this](class Expr *E) {
408 if (!getLangOpts().CPlusPlus11)
409 return VerifyIntegerConstantExpression(E);
411 getCurFunction()->SwitchStack.back()->getCond()) {
412 QualType CondType = CondExpr->getType();
413 llvm::APSInt TempVal;
414 return CheckConvertedConstantExpression(E, CondType, TempVal,
423 if (!getLangOpts().CPlusPlus11) {
424 // C99 6.8.4.2p3: The expression shall be an integer constant.
425 // However, GCC allows any evaluatable integer expression.
426 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) {
427 LHSVal = VerifyIntegerConstantExpression(LHSVal).get();
432 // GCC extension: The expression shall be an integer constant.
434 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) {
435 RHSVal = VerifyIntegerConstantExpression(RHSVal).get();
436 // Recover from an error by just forgetting about it.
440 LHS = ActOnFinishFullExpr(LHSVal, LHSVal->getExprLoc(), false,
441 getLangOpts().CPlusPlus11);
445 auto RHS = RHSVal ? ActOnFinishFullExpr(RHSVal, RHSVal->getExprLoc(), false,
446 getLangOpts().CPlusPlus11)
451 CaseStmt *CS = new (Context)
452 CaseStmt(LHS.get(), RHS.get(), CaseLoc, DotDotDotLoc, ColonLoc);
453 getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
457 /// ActOnCaseStmtBody - This installs a statement as the body of a case.
458 void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
459 DiagnoseUnusedExprResult(SubStmt);
461 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
462 CS->setSubStmt(SubStmt);
466 Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
467 Stmt *SubStmt, Scope *CurScope) {
468 DiagnoseUnusedExprResult(SubStmt);
470 if (getCurFunction()->SwitchStack.empty()) {
471 Diag(DefaultLoc, diag::err_default_not_in_switch);
475 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
476 getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
481 Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
482 SourceLocation ColonLoc, Stmt *SubStmt) {
483 // If the label was multiply defined, reject it now.
484 if (TheDecl->getStmt()) {
485 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
486 Diag(TheDecl->getLocation(), diag::note_previous_definition);
490 // Otherwise, things are good. Fill in the declaration and return it.
491 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
492 TheDecl->setStmt(LS);
493 if (!TheDecl->isGnuLocal()) {
494 TheDecl->setLocStart(IdentLoc);
495 if (!TheDecl->isMSAsmLabel()) {
496 // Don't update the location of MS ASM labels. These will result in
497 // a diagnostic, and changing the location here will mess that up.
498 TheDecl->setLocation(IdentLoc);
504 StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
505 ArrayRef<const Attr*> Attrs,
507 // Fill in the declaration and return it.
508 AttributedStmt *LS = AttributedStmt::Create(Context, AttrLoc, Attrs, SubStmt);
513 class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
514 typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
517 CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
518 void VisitBinaryOperator(BinaryOperator *E) {
519 if (E->getOpcode() == BO_Comma)
520 SemaRef.DiagnoseCommaOperator(E->getLHS(), E->getExprLoc());
521 EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
527 Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
528 ConditionResult Cond,
529 Stmt *thenStmt, SourceLocation ElseLoc,
531 if (Cond.isInvalid())
532 Cond = ConditionResult(
534 MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
535 Context.BoolTy, VK_RValue),
539 Expr *CondExpr = Cond.get().second;
540 if (!Diags.isIgnored(diag::warn_comma_operator,
541 CondExpr->getExprLoc()))
542 CommaVisitor(*this).Visit(CondExpr);
545 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), thenStmt,
546 diag::warn_empty_if_body);
548 return BuildIfStmt(IfLoc, IsConstexpr, InitStmt, Cond, thenStmt, ElseLoc,
552 StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
553 Stmt *InitStmt, ConditionResult Cond,
554 Stmt *thenStmt, SourceLocation ElseLoc,
556 if (Cond.isInvalid())
559 if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
560 getCurFunction()->setHasBranchProtectedScope();
562 DiagnoseUnusedExprResult(thenStmt);
563 DiagnoseUnusedExprResult(elseStmt);
566 IfStmt(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
567 Cond.get().second, thenStmt, ElseLoc, elseStmt);
571 struct CaseCompareFunctor {
572 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
573 const llvm::APSInt &RHS) {
574 return LHS.first < RHS;
576 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
577 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
578 return LHS.first < RHS.first;
580 bool operator()(const llvm::APSInt &LHS,
581 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
582 return LHS < RHS.first;
587 /// CmpCaseVals - Comparison predicate for sorting case values.
589 static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
590 const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
591 if (lhs.first < rhs.first)
594 if (lhs.first == rhs.first &&
595 lhs.second->getCaseLoc().getRawEncoding()
596 < rhs.second->getCaseLoc().getRawEncoding())
601 /// CmpEnumVals - Comparison predicate for sorting enumeration values.
603 static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
604 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
606 return lhs.first < rhs.first;
609 /// EqEnumVals - Comparison preficate for uniqing enumeration values.
611 static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
612 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
614 return lhs.first == rhs.first;
617 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
618 /// potentially integral-promoted expression @p expr.
619 static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
620 if (const auto *CleanUps = dyn_cast<ExprWithCleanups>(E))
621 E = CleanUps->getSubExpr();
622 while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
623 if (ImpCast->getCastKind() != CK_IntegralCast) break;
624 E = ImpCast->getSubExpr();
629 ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
630 class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
634 SwitchConvertDiagnoser(Expr *Cond)
635 : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
638 SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
639 QualType T) override {
640 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
643 SemaDiagnosticBuilder diagnoseIncomplete(
644 Sema &S, SourceLocation Loc, QualType T) override {
645 return S.Diag(Loc, diag::err_switch_incomplete_class_type)
646 << T << Cond->getSourceRange();
649 SemaDiagnosticBuilder diagnoseExplicitConv(
650 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
651 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
654 SemaDiagnosticBuilder noteExplicitConv(
655 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
656 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
657 << ConvTy->isEnumeralType() << ConvTy;
660 SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
661 QualType T) override {
662 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
665 SemaDiagnosticBuilder noteAmbiguous(
666 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
667 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
668 << ConvTy->isEnumeralType() << ConvTy;
671 SemaDiagnosticBuilder diagnoseConversion(
672 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
673 llvm_unreachable("conversion functions are permitted");
675 } SwitchDiagnoser(Cond);
677 ExprResult CondResult =
678 PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
679 if (CondResult.isInvalid())
682 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
683 return UsualUnaryConversions(CondResult.get());
686 StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
687 Stmt *InitStmt, ConditionResult Cond) {
688 if (Cond.isInvalid())
691 getCurFunction()->setHasBranchIntoScope();
693 SwitchStmt *SS = new (Context)
694 SwitchStmt(Context, InitStmt, Cond.get().first, Cond.get().second);
695 getCurFunction()->SwitchStack.push_back(SS);
699 static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
700 Val = Val.extOrTrunc(BitWidth);
701 Val.setIsSigned(IsSigned);
704 /// Check the specified case value is in range for the given unpromoted switch
706 static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
707 unsigned UnpromotedWidth, bool UnpromotedSign) {
708 // If the case value was signed and negative and the switch expression is
709 // unsigned, don't bother to warn: this is implementation-defined behavior.
710 // FIXME: Introduce a second, default-ignored warning for this case?
711 if (UnpromotedWidth < Val.getBitWidth()) {
712 llvm::APSInt ConvVal(Val);
713 AdjustAPSInt(ConvVal, UnpromotedWidth, UnpromotedSign);
714 AdjustAPSInt(ConvVal, Val.getBitWidth(), Val.isSigned());
715 // FIXME: Use different diagnostics for overflow in conversion to promoted
716 // type versus "switch expression cannot have this value". Use proper
717 // IntRange checking rather than just looking at the unpromoted type here.
719 S.Diag(Loc, diag::warn_case_value_overflow) << Val.toString(10)
720 << ConvVal.toString(10);
724 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
726 /// Returns true if we should emit a diagnostic about this case expression not
727 /// being a part of the enum used in the switch controlling expression.
728 static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
730 const Expr *CaseExpr,
731 EnumValsTy::iterator &EI,
732 EnumValsTy::iterator &EIEnd,
733 const llvm::APSInt &Val) {
737 if (const DeclRefExpr *DRE =
738 dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
739 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
740 QualType VarType = VD->getType();
741 QualType EnumType = S.Context.getTypeDeclType(ED);
742 if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
743 S.Context.hasSameUnqualifiedType(EnumType, VarType))
748 if (ED->hasAttr<FlagEnumAttr>())
749 return !S.IsValueInFlagEnum(ED, Val, false);
751 while (EI != EIEnd && EI->first < Val)
754 if (EI != EIEnd && EI->first == Val)
760 static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
762 QualType CondType = GetTypeBeforeIntegralPromotion(Cond);
763 QualType CaseType = Case->getType();
765 const EnumType *CondEnumType = CondType->getAs<EnumType>();
766 const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
767 if (!CondEnumType || !CaseEnumType)
770 // Ignore anonymous enums.
771 if (!CondEnumType->getDecl()->getIdentifier() &&
772 !CondEnumType->getDecl()->getTypedefNameForAnonDecl())
774 if (!CaseEnumType->getDecl()->getIdentifier() &&
775 !CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
778 if (S.Context.hasSameUnqualifiedType(CondType, CaseType))
781 S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types_switch)
782 << CondType << CaseType << Cond->getSourceRange()
783 << Case->getSourceRange();
787 Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
789 SwitchStmt *SS = cast<SwitchStmt>(Switch);
790 assert(SS == getCurFunction()->SwitchStack.back() &&
791 "switch stack missing push/pop!");
793 getCurFunction()->SwitchStack.pop_back();
795 if (!BodyStmt) return StmtError();
796 SS->setBody(BodyStmt, SwitchLoc);
798 Expr *CondExpr = SS->getCond();
799 if (!CondExpr) return StmtError();
801 QualType CondType = CondExpr->getType();
803 const Expr *CondExprBeforePromotion = CondExpr;
804 QualType CondTypeBeforePromotion =
805 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
808 // Integral promotions are performed (on the switch condition).
810 // A case value unrepresentable by the original switch condition
811 // type (before the promotion) doesn't make sense, even when it can
812 // be represented by the promoted type. Therefore we need to find
813 // the pre-promotion type of the switch condition.
814 if (!CondExpr->isTypeDependent()) {
815 // We have already converted the expression to an integral or enumeration
816 // type, when we started the switch statement. If we don't have an
817 // appropriate type now, just return an error.
818 if (!CondType->isIntegralOrEnumerationType())
821 if (CondExpr->isKnownToHaveBooleanValue()) {
822 // switch(bool_expr) {...} is often a programmer error, e.g.
823 // switch(n && mask) { ... } // Doh - should be "n & mask".
824 // One can always use an if statement instead of switch(bool_expr).
825 Diag(SwitchLoc, diag::warn_bool_switch_condition)
826 << CondExpr->getSourceRange();
830 // Get the bitwidth of the switched-on value after promotions. We must
831 // convert the integer case values to this width before comparison.
832 bool HasDependentValue
833 = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
834 unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(CondType);
835 bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
837 // Get the width and signedness that the condition might actually have, for
839 // FIXME: Grab an IntRange for the condition rather than using the unpromoted
841 unsigned CondWidthBeforePromotion
842 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
843 bool CondIsSignedBeforePromotion
844 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
846 // Accumulate all of the case values in a vector so that we can sort them
847 // and detect duplicates. This vector contains the APInt for the case after
848 // it has been converted to the condition type.
849 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
852 // Keep track of any GNU case ranges we see. The APSInt is the low value.
853 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
854 CaseRangesTy CaseRanges;
856 DefaultStmt *TheDefaultStmt = nullptr;
858 bool CaseListIsErroneous = false;
860 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
861 SC = SC->getNextSwitchCase()) {
863 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
864 if (TheDefaultStmt) {
865 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
866 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
868 // FIXME: Remove the default statement from the switch block so that
869 // we'll return a valid AST. This requires recursing down the AST and
870 // finding it, not something we are set up to do right now. For now,
871 // just lop the entire switch stmt out of the AST.
872 CaseListIsErroneous = true;
877 CaseStmt *CS = cast<CaseStmt>(SC);
879 Expr *Lo = CS->getLHS();
881 if (Lo->isTypeDependent() || Lo->isValueDependent()) {
882 HasDependentValue = true;
886 checkEnumTypesInSwitchStmt(*this, CondExpr, Lo);
890 if (getLangOpts().CPlusPlus11) {
891 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
892 // constant expression of the promoted type of the switch condition.
894 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue);
895 if (ConvLo.isInvalid()) {
896 CaseListIsErroneous = true;
901 // We already verified that the expression has a i-c-e value (C99
902 // 6.8.4.2p3) - get that value now.
903 LoVal = Lo->EvaluateKnownConstInt(Context);
905 // If the LHS is not the same type as the condition, insert an implicit
907 Lo = DefaultLvalueConversion(Lo).get();
908 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).get();
911 // Check the unconverted value is within the range of possible values of
912 // the switch expression.
913 checkCaseValue(*this, Lo->getLocStart(), LoVal,
914 CondWidthBeforePromotion, CondIsSignedBeforePromotion);
916 // Convert the value to the same width/sign as the condition.
917 AdjustAPSInt(LoVal, CondWidth, CondIsSigned);
921 // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
923 if (CS->getRHS()->isTypeDependent() ||
924 CS->getRHS()->isValueDependent()) {
925 HasDependentValue = true;
928 CaseRanges.push_back(std::make_pair(LoVal, CS));
930 CaseVals.push_back(std::make_pair(LoVal, CS));
934 if (!HasDependentValue) {
935 // If we don't have a default statement, check whether the
936 // condition is constant.
937 llvm::APSInt ConstantCondValue;
938 bool HasConstantCond = false;
939 if (!HasDependentValue && !TheDefaultStmt) {
940 HasConstantCond = CondExpr->EvaluateAsInt(ConstantCondValue, Context,
941 Expr::SE_AllowSideEffects);
942 assert(!HasConstantCond ||
943 (ConstantCondValue.getBitWidth() == CondWidth &&
944 ConstantCondValue.isSigned() == CondIsSigned));
946 bool ShouldCheckConstantCond = HasConstantCond;
948 // Sort all the scalar case values so we can easily detect duplicates.
949 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
951 if (!CaseVals.empty()) {
952 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
953 if (ShouldCheckConstantCond &&
954 CaseVals[i].first == ConstantCondValue)
955 ShouldCheckConstantCond = false;
957 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
958 // If we have a duplicate, report it.
959 // First, determine if either case value has a name
960 StringRef PrevString, CurrString;
961 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
962 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
963 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
964 PrevString = DeclRef->getDecl()->getName();
966 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
967 CurrString = DeclRef->getDecl()->getName();
969 SmallString<16> CaseValStr;
970 CaseVals[i-1].first.toString(CaseValStr);
972 if (PrevString == CurrString)
973 Diag(CaseVals[i].second->getLHS()->getLocStart(),
974 diag::err_duplicate_case) <<
975 (PrevString.empty() ? StringRef(CaseValStr) : PrevString);
977 Diag(CaseVals[i].second->getLHS()->getLocStart(),
978 diag::err_duplicate_case_differing_expr) <<
979 (PrevString.empty() ? StringRef(CaseValStr) : PrevString) <<
980 (CurrString.empty() ? StringRef(CaseValStr) : CurrString) <<
983 Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
984 diag::note_duplicate_case_prev);
985 // FIXME: We really want to remove the bogus case stmt from the
986 // substmt, but we have no way to do this right now.
987 CaseListIsErroneous = true;
992 // Detect duplicate case ranges, which usually don't exist at all in
994 if (!CaseRanges.empty()) {
995 // Sort all the case ranges by their low value so we can easily detect
996 // overlaps between ranges.
997 std::stable_sort(CaseRanges.begin(), CaseRanges.end());
999 // Scan the ranges, computing the high values and removing empty ranges.
1000 std::vector<llvm::APSInt> HiVals;
1001 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1002 llvm::APSInt &LoVal = CaseRanges[i].first;
1003 CaseStmt *CR = CaseRanges[i].second;
1004 Expr *Hi = CR->getRHS();
1007 if (getLangOpts().CPlusPlus11) {
1008 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
1009 // constant expression of the promoted type of the switch condition.
1011 CheckConvertedConstantExpression(Hi, CondType, HiVal,
1013 if (ConvHi.isInvalid()) {
1014 CaseListIsErroneous = true;
1019 HiVal = Hi->EvaluateKnownConstInt(Context);
1021 // If the RHS is not the same type as the condition, insert an
1023 Hi = DefaultLvalueConversion(Hi).get();
1024 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).get();
1027 // Check the unconverted value is within the range of possible values of
1028 // the switch expression.
1029 checkCaseValue(*this, Hi->getLocStart(), HiVal,
1030 CondWidthBeforePromotion, CondIsSignedBeforePromotion);
1032 // Convert the value to the same width/sign as the condition.
1033 AdjustAPSInt(HiVal, CondWidth, CondIsSigned);
1037 // If the low value is bigger than the high value, the case is empty.
1038 if (LoVal > HiVal) {
1039 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
1040 << SourceRange(CR->getLHS()->getLocStart(),
1042 CaseRanges.erase(CaseRanges.begin()+i);
1048 if (ShouldCheckConstantCond &&
1049 LoVal <= ConstantCondValue &&
1050 ConstantCondValue <= HiVal)
1051 ShouldCheckConstantCond = false;
1053 HiVals.push_back(HiVal);
1056 // Rescan the ranges, looking for overlap with singleton values and other
1057 // ranges. Since the range list is sorted, we only need to compare case
1058 // ranges with their neighbors.
1059 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1060 llvm::APSInt &CRLo = CaseRanges[i].first;
1061 llvm::APSInt &CRHi = HiVals[i];
1062 CaseStmt *CR = CaseRanges[i].second;
1064 // Check to see whether the case range overlaps with any
1066 CaseStmt *OverlapStmt = nullptr;
1067 llvm::APSInt OverlapVal(32);
1069 // Find the smallest value >= the lower bound. If I is in the
1070 // case range, then we have overlap.
1071 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
1072 CaseVals.end(), CRLo,
1073 CaseCompareFunctor());
1074 if (I != CaseVals.end() && I->first < CRHi) {
1075 OverlapVal = I->first; // Found overlap with scalar.
1076 OverlapStmt = I->second;
1079 // Find the smallest value bigger than the upper bound.
1080 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
1081 if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1082 OverlapVal = (I-1)->first; // Found overlap with scalar.
1083 OverlapStmt = (I-1)->second;
1086 // Check to see if this case stmt overlaps with the subsequent
1088 if (i && CRLo <= HiVals[i-1]) {
1089 OverlapVal = HiVals[i-1]; // Found overlap with range.
1090 OverlapStmt = CaseRanges[i-1].second;
1094 // If we have a duplicate, report it.
1095 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
1096 << OverlapVal.toString(10);
1097 Diag(OverlapStmt->getLHS()->getLocStart(),
1098 diag::note_duplicate_case_prev);
1099 // FIXME: We really want to remove the bogus case stmt from the
1100 // substmt, but we have no way to do this right now.
1101 CaseListIsErroneous = true;
1106 // Complain if we have a constant condition and we didn't find a match.
1107 if (!CaseListIsErroneous && ShouldCheckConstantCond) {
1108 // TODO: it would be nice if we printed enums as enums, chars as
1110 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1111 << ConstantCondValue.toString(10)
1112 << CondExpr->getSourceRange();
1115 // Check to see if switch is over an Enum and handles all of its
1116 // values. We only issue a warning if there is not 'default:', but
1117 // we still do the analysis to preserve this information in the AST
1118 // (which can be used by flow-based analyes).
1120 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1122 // If switch has default case, then ignore it.
1123 if (!CaseListIsErroneous && !HasConstantCond && ET &&
1124 ET->getDecl()->isCompleteDefinition()) {
1125 const EnumDecl *ED = ET->getDecl();
1126 EnumValsTy EnumVals;
1128 // Gather all enum values, set their type and sort them,
1129 // allowing easier comparison with CaseVals.
1130 for (auto *EDI : ED->enumerators()) {
1131 llvm::APSInt Val = EDI->getInitVal();
1132 AdjustAPSInt(Val, CondWidth, CondIsSigned);
1133 EnumVals.push_back(std::make_pair(Val, EDI));
1135 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1136 auto EI = EnumVals.begin(), EIEnd =
1137 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1139 // See which case values aren't in enum.
1140 for (CaseValsTy::const_iterator CI = CaseVals.begin();
1141 CI != CaseVals.end(); CI++) {
1142 Expr *CaseExpr = CI->second->getLHS();
1143 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1145 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1146 << CondTypeBeforePromotion;
1149 // See which of case ranges aren't in enum
1150 EI = EnumVals.begin();
1151 for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1152 RI != CaseRanges.end(); RI++) {
1153 Expr *CaseExpr = RI->second->getLHS();
1154 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1156 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1157 << CondTypeBeforePromotion;
1160 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1161 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1163 CaseExpr = RI->second->getRHS();
1164 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1166 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1167 << CondTypeBeforePromotion;
1170 // Check which enum vals aren't in switch
1171 auto CI = CaseVals.begin();
1172 auto RI = CaseRanges.begin();
1173 bool hasCasesNotInSwitch = false;
1175 SmallVector<DeclarationName,8> UnhandledNames;
1177 for (EI = EnumVals.begin(); EI != EIEnd; EI++){
1178 // Drop unneeded case values
1179 while (CI != CaseVals.end() && CI->first < EI->first)
1182 if (CI != CaseVals.end() && CI->first == EI->first)
1185 // Drop unneeded case ranges
1186 for (; RI != CaseRanges.end(); RI++) {
1188 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1189 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1190 if (EI->first <= Hi)
1194 if (RI == CaseRanges.end() || EI->first < RI->first) {
1195 hasCasesNotInSwitch = true;
1196 UnhandledNames.push_back(EI->second->getDeclName());
1200 if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1201 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1203 // Produce a nice diagnostic if multiple values aren't handled.
1204 if (!UnhandledNames.empty()) {
1205 DiagnosticBuilder DB = Diag(CondExpr->getExprLoc(),
1206 TheDefaultStmt ? diag::warn_def_missing_case
1207 : diag::warn_missing_case)
1208 << (int)UnhandledNames.size();
1210 for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
1212 DB << UnhandledNames[I];
1215 if (!hasCasesNotInSwitch)
1216 SS->setAllEnumCasesCovered();
1221 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt,
1222 diag::warn_empty_switch_body);
1224 // FIXME: If the case list was broken is some way, we don't have a good system
1225 // to patch it up. Instead, just return the whole substmt as broken.
1226 if (CaseListIsErroneous)
1233 Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1235 if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1238 if (const EnumType *ET = DstType->getAs<EnumType>())
1239 if (!Context.hasSameUnqualifiedType(SrcType, DstType) &&
1240 SrcType->isIntegerType()) {
1241 if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
1242 SrcExpr->isIntegerConstantExpr(Context)) {
1243 // Get the bitwidth of the enum value before promotions.
1244 unsigned DstWidth = Context.getIntWidth(DstType);
1245 bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1247 llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
1248 AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
1249 const EnumDecl *ED = ET->getDecl();
1251 if (!ED->isClosed())
1254 if (ED->hasAttr<FlagEnumAttr>()) {
1255 if (!IsValueInFlagEnum(ED, RhsVal, true))
1256 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1257 << DstType.getUnqualifiedType();
1259 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1261 EnumValsTy EnumVals;
1263 // Gather all enum values, set their type and sort them,
1264 // allowing easier comparison with rhs constant.
1265 for (auto *EDI : ED->enumerators()) {
1266 llvm::APSInt Val = EDI->getInitVal();
1267 AdjustAPSInt(Val, DstWidth, DstIsSigned);
1268 EnumVals.push_back(std::make_pair(Val, EDI));
1270 if (EnumVals.empty())
1272 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1273 EnumValsTy::iterator EIend =
1274 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1276 // See which values aren't in the enum.
1277 EnumValsTy::const_iterator EI = EnumVals.begin();
1278 while (EI != EIend && EI->first < RhsVal)
1280 if (EI == EIend || EI->first != RhsVal) {
1281 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1282 << DstType.getUnqualifiedType();
1289 StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
1291 if (Cond.isInvalid())
1294 auto CondVal = Cond.get();
1295 CheckBreakContinueBinding(CondVal.second);
1297 if (CondVal.second &&
1298 !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
1299 CommaVisitor(*this).Visit(CondVal.second);
1301 DiagnoseUnusedExprResult(Body);
1303 if (isa<NullStmt>(Body))
1304 getCurCompoundScope().setHasEmptyLoopBodies();
1306 return new (Context)
1307 WhileStmt(Context, CondVal.first, CondVal.second, Body, WhileLoc);
1311 Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1312 SourceLocation WhileLoc, SourceLocation CondLParen,
1313 Expr *Cond, SourceLocation CondRParen) {
1314 assert(Cond && "ActOnDoStmt(): missing expression");
1316 CheckBreakContinueBinding(Cond);
1317 ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
1318 if (CondResult.isInvalid())
1320 Cond = CondResult.get();
1322 CondResult = ActOnFinishFullExpr(Cond, DoLoc);
1323 if (CondResult.isInvalid())
1325 Cond = CondResult.get();
1327 DiagnoseUnusedExprResult(Body);
1329 return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1333 // Use SetVector since the diagnostic cares about the ordering of the Decl's.
1334 using DeclSetVector =
1335 llvm::SetVector<VarDecl *, llvm::SmallVector<VarDecl *, 8>,
1336 llvm::SmallPtrSet<VarDecl *, 8>>;
1338 // This visitor will traverse a conditional statement and store all
1339 // the evaluated decls into a vector. Simple is set to true if none
1340 // of the excluded constructs are used.
1341 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1342 DeclSetVector &Decls;
1343 SmallVectorImpl<SourceRange> &Ranges;
1346 typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1348 DeclExtractor(Sema &S, DeclSetVector &Decls,
1349 SmallVectorImpl<SourceRange> &Ranges) :
1350 Inherited(S.Context),
1355 bool isSimple() { return Simple; }
1357 // Replaces the method in EvaluatedExprVisitor.
1358 void VisitMemberExpr(MemberExpr* E) {
1362 // Any Stmt not whitelisted will cause the condition to be marked complex.
1363 void VisitStmt(Stmt *S) {
1367 void VisitBinaryOperator(BinaryOperator *E) {
1372 void VisitCastExpr(CastExpr *E) {
1373 Visit(E->getSubExpr());
1376 void VisitUnaryOperator(UnaryOperator *E) {
1377 // Skip checking conditionals with derefernces.
1378 if (E->getOpcode() == UO_Deref)
1381 Visit(E->getSubExpr());
1384 void VisitConditionalOperator(ConditionalOperator *E) {
1385 Visit(E->getCond());
1386 Visit(E->getTrueExpr());
1387 Visit(E->getFalseExpr());
1390 void VisitParenExpr(ParenExpr *E) {
1391 Visit(E->getSubExpr());
1394 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1395 Visit(E->getOpaqueValue()->getSourceExpr());
1396 Visit(E->getFalseExpr());
1399 void VisitIntegerLiteral(IntegerLiteral *E) { }
1400 void VisitFloatingLiteral(FloatingLiteral *E) { }
1401 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1402 void VisitCharacterLiteral(CharacterLiteral *E) { }
1403 void VisitGNUNullExpr(GNUNullExpr *E) { }
1404 void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1406 void VisitDeclRefExpr(DeclRefExpr *E) {
1407 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
1410 Ranges.push_back(E->getSourceRange());
1415 }; // end class DeclExtractor
1417 // DeclMatcher checks to see if the decls are used in a non-evaluated
1419 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1420 DeclSetVector &Decls;
1424 typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1426 DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1427 Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1428 if (!Statement) return;
1433 void VisitReturnStmt(ReturnStmt *S) {
1437 void VisitBreakStmt(BreakStmt *S) {
1441 void VisitGotoStmt(GotoStmt *S) {
1445 void VisitCastExpr(CastExpr *E) {
1446 if (E->getCastKind() == CK_LValueToRValue)
1447 CheckLValueToRValueCast(E->getSubExpr());
1449 Visit(E->getSubExpr());
1452 void CheckLValueToRValueCast(Expr *E) {
1453 E = E->IgnoreParenImpCasts();
1455 if (isa<DeclRefExpr>(E)) {
1459 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
1460 Visit(CO->getCond());
1461 CheckLValueToRValueCast(CO->getTrueExpr());
1462 CheckLValueToRValueCast(CO->getFalseExpr());
1466 if (BinaryConditionalOperator *BCO =
1467 dyn_cast<BinaryConditionalOperator>(E)) {
1468 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
1469 CheckLValueToRValueCast(BCO->getFalseExpr());
1476 void VisitDeclRefExpr(DeclRefExpr *E) {
1477 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
1478 if (Decls.count(VD))
1482 void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
1483 // Only need to visit the semantics for POE.
1484 // SyntaticForm doesn't really use the Decal.
1485 for (auto *S : POE->semantics()) {
1486 if (auto *OVE = dyn_cast<OpaqueValueExpr>(S))
1487 // Look past the OVE into the expression it binds.
1488 Visit(OVE->getSourceExpr());
1494 bool FoundDeclInUse() { return FoundDecl; }
1496 }; // end class DeclMatcher
1498 void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
1499 Expr *Third, Stmt *Body) {
1500 // Condition is empty
1501 if (!Second) return;
1503 if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
1504 Second->getLocStart()))
1507 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
1508 DeclSetVector Decls;
1509 SmallVector<SourceRange, 10> Ranges;
1510 DeclExtractor DE(S, Decls, Ranges);
1513 // Don't analyze complex conditionals.
1514 if (!DE.isSimple()) return;
1517 if (Decls.size() == 0) return;
1519 // Don't warn on volatile, static, or global variables.
1520 for (auto *VD : Decls)
1521 if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
1524 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
1525 DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
1526 DeclMatcher(S, Decls, Body).FoundDeclInUse())
1529 // Load decl names into diagnostic.
1530 if (Decls.size() > 4) {
1533 PDiag << (unsigned)Decls.size();
1534 for (auto *VD : Decls)
1535 PDiag << VD->getDeclName();
1538 for (auto Range : Ranges)
1541 S.Diag(Ranges.begin()->getBegin(), PDiag);
1544 // If Statement is an incemement or decrement, return true and sets the
1545 // variables Increment and DRE.
1546 bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
1547 DeclRefExpr *&DRE) {
1548 if (auto Cleanups = dyn_cast<ExprWithCleanups>(Statement))
1549 if (!Cleanups->cleanupsHaveSideEffects())
1550 Statement = Cleanups->getSubExpr();
1552 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
1553 switch (UO->getOpcode()) {
1554 default: return false;
1564 DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr());
1568 if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Statement)) {
1569 FunctionDecl *FD = Call->getDirectCallee();
1570 if (!FD || !FD->isOverloadedOperator()) return false;
1571 switch (FD->getOverloadedOperator()) {
1572 default: return false;
1580 DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
1587 // A visitor to determine if a continue or break statement is a
1589 class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
1590 SourceLocation BreakLoc;
1591 SourceLocation ContinueLoc;
1592 bool InSwitch = false;
1595 BreakContinueFinder(Sema &S, const Stmt* Body) :
1596 Inherited(S.Context) {
1600 typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
1602 void VisitContinueStmt(const ContinueStmt* E) {
1603 ContinueLoc = E->getContinueLoc();
1606 void VisitBreakStmt(const BreakStmt* E) {
1608 BreakLoc = E->getBreakLoc();
1611 void VisitSwitchStmt(const SwitchStmt* S) {
1612 if (const Stmt *Init = S->getInit())
1614 if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
1616 if (const Stmt *Cond = S->getCond())
1619 // Don't return break statements from the body of a switch.
1621 if (const Stmt *Body = S->getBody())
1626 void VisitForStmt(const ForStmt *S) {
1627 // Only visit the init statement of a for loop; the body
1628 // has a different break/continue scope.
1629 if (const Stmt *Init = S->getInit())
1633 void VisitWhileStmt(const WhileStmt *) {
1634 // Do nothing; the children of a while loop have a different
1635 // break/continue scope.
1638 void VisitDoStmt(const DoStmt *) {
1639 // Do nothing; the children of a while loop have a different
1640 // break/continue scope.
1643 void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
1644 // Only visit the initialization of a for loop; the body
1645 // has a different break/continue scope.
1646 if (const Stmt *Range = S->getRangeStmt())
1648 if (const Stmt *Begin = S->getBeginStmt())
1650 if (const Stmt *End = S->getEndStmt())
1654 void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
1655 // Only visit the initialization of a for loop; the body
1656 // has a different break/continue scope.
1657 if (const Stmt *Element = S->getElement())
1659 if (const Stmt *Collection = S->getCollection())
1663 bool ContinueFound() { return ContinueLoc.isValid(); }
1664 bool BreakFound() { return BreakLoc.isValid(); }
1665 SourceLocation GetContinueLoc() { return ContinueLoc; }
1666 SourceLocation GetBreakLoc() { return BreakLoc; }
1668 }; // end class BreakContinueFinder
1670 // Emit a warning when a loop increment/decrement appears twice per loop
1671 // iteration. The conditions which trigger this warning are:
1672 // 1) The last statement in the loop body and the third expression in the
1673 // for loop are both increment or both decrement of the same variable
1674 // 2) No continue statements in the loop body.
1675 void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
1676 // Return when there is nothing to check.
1677 if (!Body || !Third) return;
1679 if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
1680 Third->getLocStart()))
1683 // Get the last statement from the loop body.
1684 CompoundStmt *CS = dyn_cast<CompoundStmt>(Body);
1685 if (!CS || CS->body_empty()) return;
1686 Stmt *LastStmt = CS->body_back();
1687 if (!LastStmt) return;
1689 bool LoopIncrement, LastIncrement;
1690 DeclRefExpr *LoopDRE, *LastDRE;
1692 if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
1693 if (!ProcessIterationStmt(S, LastStmt, LastIncrement, LastDRE)) return;
1695 // Check that the two statements are both increments or both decrements
1696 // on the same variable.
1697 if (LoopIncrement != LastIncrement ||
1698 LoopDRE->getDecl() != LastDRE->getDecl()) return;
1700 if (BreakContinueFinder(S, Body).ContinueFound()) return;
1702 S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
1703 << LastDRE->getDecl() << LastIncrement;
1704 S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
1711 void Sema::CheckBreakContinueBinding(Expr *E) {
1712 if (!E || getLangOpts().CPlusPlus)
1714 BreakContinueFinder BCFinder(*this, E);
1715 Scope *BreakParent = CurScope->getBreakParent();
1716 if (BCFinder.BreakFound() && BreakParent) {
1717 if (BreakParent->getFlags() & Scope::SwitchScope) {
1718 Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
1720 Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
1723 } else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
1724 Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
1729 StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
1730 Stmt *First, ConditionResult Second,
1731 FullExprArg third, SourceLocation RParenLoc,
1733 if (Second.isInvalid())
1736 if (!getLangOpts().CPlusPlus) {
1737 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
1738 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1739 // declare identifiers for objects having storage class 'auto' or
1741 for (auto *DI : DS->decls()) {
1742 VarDecl *VD = dyn_cast<VarDecl>(DI);
1743 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
1746 Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
1747 DI->setInvalidDecl();
1753 CheckBreakContinueBinding(Second.get().second);
1754 CheckBreakContinueBinding(third.get());
1756 if (!Second.get().first)
1757 CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
1759 CheckForRedundantIteration(*this, third.get(), Body);
1761 if (Second.get().second &&
1762 !Diags.isIgnored(diag::warn_comma_operator,
1763 Second.get().second->getExprLoc()))
1764 CommaVisitor(*this).Visit(Second.get().second);
1766 Expr *Third = third.release().getAs<Expr>();
1768 DiagnoseUnusedExprResult(First);
1769 DiagnoseUnusedExprResult(Third);
1770 DiagnoseUnusedExprResult(Body);
1772 if (isa<NullStmt>(Body))
1773 getCurCompoundScope().setHasEmptyLoopBodies();
1775 return new (Context)
1776 ForStmt(Context, First, Second.get().second, Second.get().first, Third,
1777 Body, ForLoc, LParenLoc, RParenLoc);
1780 /// In an Objective C collection iteration statement:
1782 /// x can be an arbitrary l-value expression. Bind it up as a
1783 /// full-expression.
1784 StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
1785 // Reduce placeholder expressions here. Note that this rejects the
1786 // use of pseudo-object l-values in this position.
1787 ExprResult result = CheckPlaceholderExpr(E);
1788 if (result.isInvalid()) return StmtError();
1791 ExprResult FullExpr = ActOnFinishFullExpr(E);
1792 if (FullExpr.isInvalid())
1794 return StmtResult(static_cast<Stmt*>(FullExpr.get()));
1798 Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
1802 ExprResult result = CorrectDelayedTyposInExpr(collection);
1803 if (!result.isUsable())
1805 collection = result.get();
1807 // Bail out early if we've got a type-dependent expression.
1808 if (collection->isTypeDependent()) return collection;
1810 // Perform normal l-value conversion.
1811 result = DefaultFunctionArrayLvalueConversion(collection);
1812 if (result.isInvalid())
1814 collection = result.get();
1816 // The operand needs to have object-pointer type.
1817 // TODO: should we do a contextual conversion?
1818 const ObjCObjectPointerType *pointerType =
1819 collection->getType()->getAs<ObjCObjectPointerType>();
1821 return Diag(forLoc, diag::err_collection_expr_type)
1822 << collection->getType() << collection->getSourceRange();
1824 // Check that the operand provides
1825 // - countByEnumeratingWithState:objects:count:
1826 const ObjCObjectType *objectType = pointerType->getObjectType();
1827 ObjCInterfaceDecl *iface = objectType->getInterface();
1829 // If we have a forward-declared type, we can't do this check.
1830 // Under ARC, it is an error not to have a forward-declared class.
1832 (getLangOpts().ObjCAutoRefCount
1833 ? RequireCompleteType(forLoc, QualType(objectType, 0),
1834 diag::err_arc_collection_forward, collection)
1835 : !isCompleteType(forLoc, QualType(objectType, 0)))) {
1836 // Otherwise, if we have any useful type information, check that
1837 // the type declares the appropriate method.
1838 } else if (iface || !objectType->qual_empty()) {
1839 IdentifierInfo *selectorIdents[] = {
1840 &Context.Idents.get("countByEnumeratingWithState"),
1841 &Context.Idents.get("objects"),
1842 &Context.Idents.get("count")
1844 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
1846 ObjCMethodDecl *method = nullptr;
1848 // If there's an interface, look in both the public and private APIs.
1850 method = iface->lookupInstanceMethod(selector);
1851 if (!method) method = iface->lookupPrivateMethod(selector);
1854 // Also check protocol qualifiers.
1856 method = LookupMethodInQualifiedType(selector, pointerType,
1859 // If we didn't find it anywhere, give up.
1861 Diag(forLoc, diag::warn_collection_expr_type)
1862 << collection->getType() << selector << collection->getSourceRange();
1865 // TODO: check for an incompatible signature?
1868 // Wrap up any cleanups in the expression.
1873 Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
1874 Stmt *First, Expr *collection,
1875 SourceLocation RParenLoc) {
1876 getCurFunction()->setHasBranchProtectedScope();
1878 ExprResult CollectionExprResult =
1879 CheckObjCForCollectionOperand(ForLoc, collection);
1883 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
1884 if (!DS->isSingleDecl())
1885 return StmtError(Diag((*DS->decl_begin())->getLocation(),
1886 diag::err_toomany_element_decls));
1888 VarDecl *D = dyn_cast<VarDecl>(DS->getSingleDecl());
1889 if (!D || D->isInvalidDecl())
1892 FirstType = D->getType();
1893 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1894 // declare identifiers for objects having storage class 'auto' or
1896 if (!D->hasLocalStorage())
1897 return StmtError(Diag(D->getLocation(),
1898 diag::err_non_local_variable_decl_in_for));
1900 // If the type contained 'auto', deduce the 'auto' to 'id'.
1901 if (FirstType->getContainedAutoType()) {
1902 OpaqueValueExpr OpaqueId(D->getLocation(), Context.getObjCIdType(),
1904 Expr *DeducedInit = &OpaqueId;
1905 if (DeduceAutoType(D->getTypeSourceInfo(), DeducedInit, FirstType) ==
1907 DiagnoseAutoDeductionFailure(D, DeducedInit);
1908 if (FirstType.isNull()) {
1909 D->setInvalidDecl();
1913 D->setType(FirstType);
1915 if (!inTemplateInstantiation()) {
1916 SourceLocation Loc =
1917 D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
1918 Diag(Loc, diag::warn_auto_var_is_id)
1919 << D->getDeclName();
1924 Expr *FirstE = cast<Expr>(First);
1925 if (!FirstE->isTypeDependent() && !FirstE->isLValue())
1926 return StmtError(Diag(First->getLocStart(),
1927 diag::err_selector_element_not_lvalue)
1928 << First->getSourceRange());
1930 FirstType = static_cast<Expr*>(First)->getType();
1931 if (FirstType.isConstQualified())
1932 Diag(ForLoc, diag::err_selector_element_const_type)
1933 << FirstType << First->getSourceRange();
1935 if (!FirstType->isDependentType() &&
1936 !FirstType->isObjCObjectPointerType() &&
1937 !FirstType->isBlockPointerType())
1938 return StmtError(Diag(ForLoc, diag::err_selector_element_type)
1939 << FirstType << First->getSourceRange());
1942 if (CollectionExprResult.isInvalid())
1945 CollectionExprResult = ActOnFinishFullExpr(CollectionExprResult.get());
1946 if (CollectionExprResult.isInvalid())
1949 return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
1950 nullptr, ForLoc, RParenLoc);
1953 /// Finish building a variable declaration for a for-range statement.
1954 /// \return true if an error occurs.
1955 static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
1956 SourceLocation Loc, int DiagID) {
1957 if (Decl->getType()->isUndeducedType()) {
1958 ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
1959 if (!Res.isUsable()) {
1960 Decl->setInvalidDecl();
1966 // Deduce the type for the iterator variable now rather than leaving it to
1967 // AddInitializerToDecl, so we can produce a more suitable diagnostic.
1969 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
1970 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitType) ==
1972 SemaRef.Diag(Loc, DiagID) << Init->getType();
1973 if (InitType.isNull()) {
1974 Decl->setInvalidDecl();
1977 Decl->setType(InitType);
1979 // In ARC, infer lifetime.
1980 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
1981 // we're doing the equivalent of fast iteration.
1982 if (SemaRef.getLangOpts().ObjCAutoRefCount &&
1983 SemaRef.inferObjCARCLifetime(Decl))
1984 Decl->setInvalidDecl();
1986 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false);
1987 SemaRef.FinalizeDeclaration(Decl);
1988 SemaRef.CurContext->addHiddenDecl(Decl);
1993 // An enum to represent whether something is dealing with a call to begin()
1994 // or a call to end() in a range-based for loop.
1995 enum BeginEndFunction {
2000 /// Produce a note indicating which begin/end function was implicitly called
2001 /// by a C++11 for-range statement. This is often not obvious from the code,
2002 /// nor from the diagnostics produced when analysing the implicit expressions
2003 /// required in a for-range statement.
2004 void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2005 BeginEndFunction BEF) {
2006 CallExpr *CE = dyn_cast<CallExpr>(E);
2009 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
2012 SourceLocation Loc = D->getLocation();
2014 std::string Description;
2015 bool IsTemplate = false;
2016 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2017 Description = SemaRef.getTemplateArgumentBindingsText(
2018 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
2022 SemaRef.Diag(Loc, diag::note_for_range_begin_end)
2023 << BEF << IsTemplate << Description << E->getType();
2026 /// Build a variable declaration for a for-range statement.
2027 VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
2028 QualType Type, const char *Name) {
2029 DeclContext *DC = SemaRef.CurContext;
2030 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
2031 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
2032 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
2034 Decl->setImplicit();
2040 static bool ObjCEnumerationCollection(Expr *Collection) {
2041 return !Collection->isTypeDependent()
2042 && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2045 /// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
2047 /// C++11 [stmt.ranged]:
2048 /// A range-based for statement is equivalent to
2051 /// auto && __range = range-init;
2052 /// for ( auto __begin = begin-expr,
2053 /// __end = end-expr;
2054 /// __begin != __end;
2056 /// for-range-declaration = *__begin;
2061 /// The body of the loop is not available yet, since it cannot be analysed until
2062 /// we have determined the type of the for-range-declaration.
2063 StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
2064 SourceLocation CoawaitLoc, Stmt *First,
2065 SourceLocation ColonLoc, Expr *Range,
2066 SourceLocation RParenLoc,
2067 BuildForRangeKind Kind) {
2071 if (Range && ObjCEnumerationCollection(Range))
2072 return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
2074 DeclStmt *DS = dyn_cast<DeclStmt>(First);
2075 assert(DS && "first part of for range not a decl stmt");
2077 if (!DS->isSingleDecl()) {
2078 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range);
2082 Decl *LoopVar = DS->getSingleDecl();
2083 if (LoopVar->isInvalidDecl() || !Range ||
2084 DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) {
2085 LoopVar->setInvalidDecl();
2089 // Build the coroutine state immediately and not later during template
2091 if (!CoawaitLoc.isInvalid()) {
2092 if (!ActOnCoroutineBodyStart(S, CoawaitLoc, "co_await"))
2096 // Build auto && __range = range-init
2097 SourceLocation RangeLoc = Range->getLocStart();
2098 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
2099 Context.getAutoRRefDeductType(),
2101 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
2102 diag::err_for_range_deduction_failure)) {
2103 LoopVar->setInvalidDecl();
2107 // Claim the type doesn't contain auto: we've already done the checking.
2108 DeclGroupPtrTy RangeGroup =
2109 BuildDeclaratorGroup(MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2110 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
2111 if (RangeDecl.isInvalid()) {
2112 LoopVar->setInvalidDecl();
2116 return BuildCXXForRangeStmt(ForLoc, CoawaitLoc, ColonLoc, RangeDecl.get(),
2117 /*BeginStmt=*/nullptr, /*EndStmt=*/nullptr,
2118 /*Cond=*/nullptr, /*Inc=*/nullptr,
2119 DS, RParenLoc, Kind);
2122 /// \brief Create the initialization, compare, and increment steps for
2123 /// the range-based for loop expression.
2124 /// This function does not handle array-based for loops,
2125 /// which are created in Sema::BuildCXXForRangeStmt.
2127 /// \returns a ForRangeStatus indicating success or what kind of error occurred.
2128 /// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2129 /// CandidateSet and BEF are set and some non-success value is returned on
2131 static Sema::ForRangeStatus
2132 BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2133 QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2134 SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2135 OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2136 ExprResult *EndExpr, BeginEndFunction *BEF) {
2137 DeclarationNameInfo BeginNameInfo(
2138 &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
2139 DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
2142 LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2143 Sema::LookupMemberName);
2144 LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2146 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2147 // - if _RangeT is a class type, the unqualified-ids begin and end are
2148 // looked up in the scope of class _RangeT as if by class member access
2149 // lookup (3.4.5), and if either (or both) finds at least one
2150 // declaration, begin-expr and end-expr are __range.begin() and
2151 // __range.end(), respectively;
2152 SemaRef.LookupQualifiedName(BeginMemberLookup, D);
2153 SemaRef.LookupQualifiedName(EndMemberLookup, D);
2155 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2156 SourceLocation RangeLoc = BeginVar->getLocation();
2157 *BEF = BeginMemberLookup.empty() ? BEF_end : BEF_begin;
2159 SemaRef.Diag(RangeLoc, diag::err_for_range_member_begin_end_mismatch)
2160 << RangeLoc << BeginRange->getType() << *BEF;
2161 return Sema::FRS_DiagnosticIssued;
2164 // - otherwise, begin-expr and end-expr are begin(__range) and
2165 // end(__range), respectively, where begin and end are looked up with
2166 // argument-dependent lookup (3.4.2). For the purposes of this name
2167 // lookup, namespace std is an associated namespace.
2172 Sema::ForRangeStatus RangeStatus =
2173 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
2174 BeginMemberLookup, CandidateSet,
2175 BeginRange, BeginExpr);
2177 if (RangeStatus != Sema::FRS_Success) {
2178 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2179 SemaRef.Diag(BeginRange->getLocStart(), diag::note_in_for_range)
2180 << ColonLoc << BEF_begin << BeginRange->getType();
2183 if (!CoawaitLoc.isInvalid()) {
2184 // FIXME: getCurScope() should not be used during template instantiation.
2185 // We should pick up the set of unqualified lookup results for operator
2186 // co_await during the initial parse.
2187 *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
2189 if (BeginExpr->isInvalid())
2190 return Sema::FRS_DiagnosticIssued;
2192 if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
2193 diag::err_for_range_iter_deduction_failure)) {
2194 NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
2195 return Sema::FRS_DiagnosticIssued;
2200 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
2201 EndMemberLookup, CandidateSet,
2203 if (RangeStatus != Sema::FRS_Success) {
2204 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2205 SemaRef.Diag(EndRange->getLocStart(), diag::note_in_for_range)
2206 << ColonLoc << BEF_end << EndRange->getType();
2209 if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2210 diag::err_for_range_iter_deduction_failure)) {
2211 NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
2212 return Sema::FRS_DiagnosticIssued;
2214 return Sema::FRS_Success;
2217 /// Speculatively attempt to dereference an invalid range expression.
2218 /// If the attempt fails, this function will return a valid, null StmtResult
2219 /// and emit no diagnostics.
2220 static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2221 SourceLocation ForLoc,
2222 SourceLocation CoawaitLoc,
2224 SourceLocation ColonLoc,
2226 SourceLocation RangeLoc,
2227 SourceLocation RParenLoc) {
2228 // Determine whether we can rebuild the for-range statement with a
2229 // dereferenced range expression.
2230 ExprResult AdjustedRange;
2232 Sema::SFINAETrap Trap(SemaRef);
2234 AdjustedRange = SemaRef.BuildUnaryOp(S, RangeLoc, UO_Deref, Range);
2235 if (AdjustedRange.isInvalid())
2236 return StmtResult();
2238 StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2239 S, ForLoc, CoawaitLoc, LoopVarDecl, ColonLoc, AdjustedRange.get(),
2240 RParenLoc, Sema::BFRK_Check);
2242 return StmtResult();
2245 // The attempt to dereference worked well enough that it could produce a valid
2246 // loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2247 // case there are any other (non-fatal) problems with it.
2248 SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
2249 << Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
2250 return SemaRef.ActOnCXXForRangeStmt(S, ForLoc, CoawaitLoc, LoopVarDecl,
2251 ColonLoc, AdjustedRange.get(), RParenLoc,
2252 Sema::BFRK_Rebuild);
2256 /// RAII object to automatically invalidate a declaration if an error occurs.
2257 struct InvalidateOnErrorScope {
2258 InvalidateOnErrorScope(Sema &SemaRef, Decl *D, bool Enabled)
2259 : Trap(SemaRef.Diags), D(D), Enabled(Enabled) {}
2260 ~InvalidateOnErrorScope() {
2261 if (Enabled && Trap.hasErrorOccurred())
2262 D->setInvalidDecl();
2265 DiagnosticErrorTrap Trap;
2271 /// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2273 Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
2274 SourceLocation ColonLoc, Stmt *RangeDecl,
2275 Stmt *Begin, Stmt *End, Expr *Cond,
2276 Expr *Inc, Stmt *LoopVarDecl,
2277 SourceLocation RParenLoc, BuildForRangeKind Kind) {
2278 // FIXME: This should not be used during template instantiation. We should
2279 // pick up the set of unqualified lookup results for the != and + operators
2280 // in the initial parse.
2282 // Testcase (accepts-invalid):
2283 // template<typename T> void f() { for (auto x : T()) {} }
2284 // namespace N { struct X { X begin(); X end(); int operator*(); }; }
2285 // bool operator!=(N::X, N::X); void operator++(N::X);
2286 // void g() { f<N::X>(); }
2287 Scope *S = getCurScope();
2289 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
2290 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
2291 QualType RangeVarType = RangeVar->getType();
2293 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
2294 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
2296 // If we hit any errors, mark the loop variable as invalid if its type
2298 InvalidateOnErrorScope Invalidate(*this, LoopVar,
2299 LoopVar->getType()->isUndeducedType());
2301 StmtResult BeginDeclStmt = Begin;
2302 StmtResult EndDeclStmt = End;
2303 ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2305 if (RangeVarType->isDependentType()) {
2306 // The range is implicitly used as a placeholder when it is dependent.
2307 RangeVar->markUsed(Context);
2309 // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2310 // them in properly when we instantiate the loop.
2311 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2312 if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
2313 for (auto *Binding : DD->bindings())
2314 Binding->setType(Context.DependentTy);
2315 LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
2317 } else if (!BeginDeclStmt.get()) {
2318 SourceLocation RangeLoc = RangeVar->getLocation();
2320 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2322 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2323 VK_LValue, ColonLoc);
2324 if (BeginRangeRef.isInvalid())
2327 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2328 VK_LValue, ColonLoc);
2329 if (EndRangeRef.isInvalid())
2332 QualType AutoType = Context.getAutoDeductType();
2333 Expr *Range = RangeVar->getInit();
2336 QualType RangeType = Range->getType();
2338 if (RequireCompleteType(RangeLoc, RangeType,
2339 diag::err_for_range_incomplete_type))
2342 // Build auto __begin = begin-expr, __end = end-expr.
2343 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2345 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2348 // Build begin-expr and end-expr and attach to __begin and __end variables.
2349 ExprResult BeginExpr, EndExpr;
2350 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2351 // - if _RangeT is an array type, begin-expr and end-expr are __range and
2352 // __range + __bound, respectively, where __bound is the array bound. If
2353 // _RangeT is an array of unknown size or an array of incomplete type,
2354 // the program is ill-formed;
2356 // begin-expr is __range.
2357 BeginExpr = BeginRangeRef;
2358 if (!CoawaitLoc.isInvalid()) {
2359 BeginExpr = ActOnCoawaitExpr(S, ColonLoc, BeginExpr.get());
2360 if (BeginExpr.isInvalid())
2363 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2364 diag::err_for_range_iter_deduction_failure)) {
2365 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2369 // Find the array bound.
2370 ExprResult BoundExpr;
2371 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
2372 BoundExpr = IntegerLiteral::Create(
2373 Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc);
2374 else if (const VariableArrayType *VAT =
2375 dyn_cast<VariableArrayType>(UnqAT)) {
2376 // For a variably modified type we can't just use the expression within
2377 // the array bounds, since we don't want that to be re-evaluated here.
2378 // Rather, we need to determine what it was when the array was first
2379 // created - so we resort to using sizeof(vla)/sizeof(element).
2383 // b = -1; <-- This should not affect the num of iterations below
2384 // for (int &c : vla) { .. }
2387 // FIXME: This results in codegen generating IR that recalculates the
2388 // run-time number of elements (as opposed to just using the IR Value
2389 // that corresponds to the run-time value of each bound that was
2390 // generated when the array was created.) If this proves too embarassing
2391 // even for unoptimized IR, consider passing a magic-value/cookie to
2392 // codegen that then knows to simply use that initial llvm::Value (that
2393 // corresponds to the bound at time of array creation) within
2394 // getelementptr. But be prepared to pay the price of increasing a
2395 // customized form of coupling between the two components - which could
2396 // be hard to maintain as the codebase evolves.
2398 ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2399 EndVar->getLocation(), UETT_SizeOf,
2401 CreateParsedType(VAT->desugar(), Context.getTrivialTypeSourceInfo(
2402 VAT->desugar(), RangeLoc))
2404 EndVar->getSourceRange());
2405 if (SizeOfVLAExprR.isInvalid())
2408 ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2409 EndVar->getLocation(), UETT_SizeOf,
2411 CreateParsedType(VAT->desugar(),
2412 Context.getTrivialTypeSourceInfo(
2413 VAT->getElementType(), RangeLoc))
2415 EndVar->getSourceRange());
2416 if (SizeOfEachElementExprR.isInvalid())
2420 ActOnBinOp(S, EndVar->getLocation(), tok::slash,
2421 SizeOfVLAExprR.get(), SizeOfEachElementExprR.get());
2422 if (BoundExpr.isInvalid())
2426 // Can't be a DependentSizedArrayType or an IncompleteArrayType since
2427 // UnqAT is not incomplete and Range is not type-dependent.
2428 llvm_unreachable("Unexpected array type in for-range");
2431 // end-expr is __range + __bound.
2432 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
2434 if (EndExpr.isInvalid())
2436 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
2437 diag::err_for_range_iter_deduction_failure)) {
2438 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2442 OverloadCandidateSet CandidateSet(RangeLoc,
2443 OverloadCandidateSet::CSK_Normal);
2444 BeginEndFunction BEFFailure;
2445 ForRangeStatus RangeStatus = BuildNonArrayForRange(
2446 *this, BeginRangeRef.get(), EndRangeRef.get(), RangeType, BeginVar,
2447 EndVar, ColonLoc, CoawaitLoc, &CandidateSet, &BeginExpr, &EndExpr,
2450 if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2451 BEFFailure == BEF_begin) {
2452 // If the range is being built from an array parameter, emit a
2453 // a diagnostic that it is being treated as a pointer.
2454 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Range)) {
2455 if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
2456 QualType ArrayTy = PVD->getOriginalType();
2457 QualType PointerTy = PVD->getType();
2458 if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2459 Diag(Range->getLocStart(), diag::err_range_on_array_parameter)
2460 << RangeLoc << PVD << ArrayTy << PointerTy;
2461 Diag(PVD->getLocation(), diag::note_declared_at);
2467 // If building the range failed, try dereferencing the range expression
2468 // unless a diagnostic was issued or the end function is problematic.
2469 StmtResult SR = RebuildForRangeWithDereference(*this, S, ForLoc,
2471 LoopVarDecl, ColonLoc,
2474 if (SR.isInvalid() || SR.isUsable())
2478 // Otherwise, emit diagnostics if we haven't already.
2479 if (RangeStatus == FRS_NoViableFunction) {
2480 Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2481 Diag(Range->getLocStart(), diag::err_for_range_invalid)
2482 << RangeLoc << Range->getType() << BEFFailure;
2483 CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Range);
2485 // Return an error if no fix was discovered.
2486 if (RangeStatus != FRS_Success)
2490 assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
2491 "invalid range expression in for loop");
2493 // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2494 // C++1z removes this restriction.
2495 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2496 if (!Context.hasSameType(BeginType, EndType)) {
2497 Diag(RangeLoc, getLangOpts().CPlusPlus17
2498 ? diag::warn_for_range_begin_end_types_differ
2499 : diag::ext_for_range_begin_end_types_differ)
2500 << BeginType << EndType;
2501 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2502 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2506 ActOnDeclStmt(ConvertDeclToDeclGroup(BeginVar), ColonLoc, ColonLoc);
2508 ActOnDeclStmt(ConvertDeclToDeclGroup(EndVar), ColonLoc, ColonLoc);
2510 const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2511 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2512 VK_LValue, ColonLoc);
2513 if (BeginRef.isInvalid())
2516 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
2517 VK_LValue, ColonLoc);
2518 if (EndRef.isInvalid())
2521 // Build and check __begin != __end expression.
2522 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
2523 BeginRef.get(), EndRef.get());
2524 if (!NotEqExpr.isInvalid())
2525 NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
2526 if (!NotEqExpr.isInvalid())
2527 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
2528 if (NotEqExpr.isInvalid()) {
2529 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2530 << RangeLoc << 0 << BeginRangeRef.get()->getType();
2531 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2532 if (!Context.hasSameType(BeginType, EndType))
2533 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2537 // Build and check ++__begin expression.
2538 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2539 VK_LValue, ColonLoc);
2540 if (BeginRef.isInvalid())
2543 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
2544 if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
2545 // FIXME: getCurScope() should not be used during template instantiation.
2546 // We should pick up the set of unqualified lookup results for operator
2547 // co_await during the initial parse.
2548 IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
2549 if (!IncrExpr.isInvalid())
2550 IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
2551 if (IncrExpr.isInvalid()) {
2552 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2553 << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
2554 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2558 // Build and check *__begin expression.
2559 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2560 VK_LValue, ColonLoc);
2561 if (BeginRef.isInvalid())
2564 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
2565 if (DerefExpr.isInvalid()) {
2566 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2567 << RangeLoc << 1 << BeginRangeRef.get()->getType();
2568 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2572 // Attach *__begin as initializer for VD. Don't touch it if we're just
2573 // trying to determine whether this would be a valid range.
2574 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2575 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false);
2576 if (LoopVar->isInvalidDecl())
2577 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2581 // Don't bother to actually allocate the result if we're just trying to
2582 // determine whether it would be valid.
2583 if (Kind == BFRK_Check)
2584 return StmtResult();
2586 return new (Context) CXXForRangeStmt(
2587 RangeDS, cast_or_null<DeclStmt>(BeginDeclStmt.get()),
2588 cast_or_null<DeclStmt>(EndDeclStmt.get()), NotEqExpr.get(),
2589 IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
2590 ColonLoc, RParenLoc);
2593 /// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
2595 StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
2598 ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);
2600 ForStmt->setBody(B);
2604 // Warn when the loop variable is a const reference that creates a copy.
2605 // Suggest using the non-reference type for copies. If a copy can be prevented
2606 // suggest the const reference type that would do so.
2607 // For instance, given "for (const &Foo : Range)", suggest
2608 // "for (const Foo : Range)" to denote a copy is made for the loop. If
2609 // possible, also suggest "for (const &Bar : Range)" if this type prevents
2610 // the copy altogether.
2611 static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
2613 QualType RangeInitType) {
2614 const Expr *InitExpr = VD->getInit();
2618 QualType VariableType = VD->getType();
2620 if (auto Cleanups = dyn_cast<ExprWithCleanups>(InitExpr))
2621 if (!Cleanups->cleanupsHaveSideEffects())
2622 InitExpr = Cleanups->getSubExpr();
2624 const MaterializeTemporaryExpr *MTE =
2625 dyn_cast<MaterializeTemporaryExpr>(InitExpr);
2631 const Expr *E = MTE->GetTemporaryExpr()->IgnoreImpCasts();
2633 // Searching for either UnaryOperator for dereference of a pointer or
2634 // CXXOperatorCallExpr for handling iterators.
2635 while (!isa<CXXOperatorCallExpr>(E) && !isa<UnaryOperator>(E)) {
2636 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(E)) {
2638 } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(E)) {
2639 const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
2642 const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
2643 E = MTE->GetTemporaryExpr();
2645 E = E->IgnoreImpCasts();
2648 bool ReturnsReference = false;
2649 if (isa<UnaryOperator>(E)) {
2650 ReturnsReference = true;
2652 const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(E);
2653 const FunctionDecl *FD = Call->getDirectCallee();
2654 QualType ReturnType = FD->getReturnType();
2655 ReturnsReference = ReturnType->isReferenceType();
2658 if (ReturnsReference) {
2659 // Loop variable creates a temporary. Suggest either to go with
2660 // non-reference loop variable to indiciate a copy is made, or
2661 // the correct time to bind a const reference.
2662 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_const_reference_copy)
2663 << VD << VariableType << E->getType();
2664 QualType NonReferenceType = VariableType.getNonReferenceType();
2665 NonReferenceType.removeLocalConst();
2666 QualType NewReferenceType =
2667 SemaRef.Context.getLValueReferenceType(E->getType().withConst());
2668 SemaRef.Diag(VD->getLocStart(), diag::note_use_type_or_non_reference)
2669 << NonReferenceType << NewReferenceType << VD->getSourceRange();
2671 // The range always returns a copy, so a temporary is always created.
2672 // Suggest removing the reference from the loop variable.
2673 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_variable_always_copy)
2674 << VD << RangeInitType;
2675 QualType NonReferenceType = VariableType.getNonReferenceType();
2676 NonReferenceType.removeLocalConst();
2677 SemaRef.Diag(VD->getLocStart(), diag::note_use_non_reference_type)
2678 << NonReferenceType << VD->getSourceRange();
2682 // Warns when the loop variable can be changed to a reference type to
2683 // prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
2684 // "for (const Foo &x : Range)" if this form does not make a copy.
2685 static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
2686 const VarDecl *VD) {
2687 const Expr *InitExpr = VD->getInit();
2691 QualType VariableType = VD->getType();
2693 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(InitExpr)) {
2694 if (!CE->getConstructor()->isCopyConstructor())
2696 } else if (const CastExpr *CE = dyn_cast<CastExpr>(InitExpr)) {
2697 if (CE->getCastKind() != CK_LValueToRValue)
2703 // TODO: Determine a maximum size that a POD type can be before a diagnostic
2704 // should be emitted. Also, only ignore POD types with trivial copy
2706 if (VariableType.isPODType(SemaRef.Context))
2709 // Suggest changing from a const variable to a const reference variable
2710 // if doing so will prevent a copy.
2711 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
2712 << VD << VariableType << InitExpr->getType();
2713 SemaRef.Diag(VD->getLocStart(), diag::note_use_reference_type)
2714 << SemaRef.Context.getLValueReferenceType(VariableType)
2715 << VD->getSourceRange();
2718 /// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
2719 /// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
2720 /// using "const foo x" to show that a copy is made
2721 /// 2) for (const bar &x : foos) where bar is a temporary intialized by bar.
2722 /// Suggest either "const bar x" to keep the copying or "const foo& x" to
2723 /// prevent the copy.
2724 /// 3) for (const foo x : foos) where x is constructed from a reference foo.
2725 /// Suggest "const foo &x" to prevent the copy.
2726 static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
2727 const CXXForRangeStmt *ForStmt) {
2728 if (SemaRef.Diags.isIgnored(diag::warn_for_range_const_reference_copy,
2729 ForStmt->getLocStart()) &&
2730 SemaRef.Diags.isIgnored(diag::warn_for_range_variable_always_copy,
2731 ForStmt->getLocStart()) &&
2732 SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
2733 ForStmt->getLocStart())) {
2737 const VarDecl *VD = ForStmt->getLoopVariable();
2741 QualType VariableType = VD->getType();
2743 if (VariableType->isIncompleteType())
2746 const Expr *InitExpr = VD->getInit();
2750 if (VariableType->isReferenceType()) {
2751 DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
2752 ForStmt->getRangeInit()->getType());
2753 } else if (VariableType.isConstQualified()) {
2754 DiagnoseForRangeConstVariableCopies(SemaRef, VD);
2758 /// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
2759 /// This is a separate step from ActOnCXXForRangeStmt because analysis of the
2760 /// body cannot be performed until after the type of the range variable is
2762 StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
2766 if (isa<ObjCForCollectionStmt>(S))
2767 return FinishObjCForCollectionStmt(S, B);
2769 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
2770 ForStmt->setBody(B);
2772 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
2773 diag::warn_empty_range_based_for_body);
2775 DiagnoseForRangeVariableCopies(*this, ForStmt);
2780 StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
2781 SourceLocation LabelLoc,
2782 LabelDecl *TheDecl) {
2783 getCurFunction()->setHasBranchIntoScope();
2784 TheDecl->markUsed(Context);
2785 return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
2789 Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
2791 // Convert operand to void*
2792 if (!E->isTypeDependent()) {
2793 QualType ETy = E->getType();
2794 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
2795 ExprResult ExprRes = E;
2796 AssignConvertType ConvTy =
2797 CheckSingleAssignmentConstraints(DestTy, ExprRes);
2798 if (ExprRes.isInvalid())
2801 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
2805 ExprResult ExprRes = ActOnFinishFullExpr(E);
2806 if (ExprRes.isInvalid())
2810 getCurFunction()->setHasIndirectGoto();
2812 return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
2815 static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
2816 const Scope &DestScope) {
2817 if (!S.CurrentSEHFinally.empty() &&
2818 DestScope.Contains(*S.CurrentSEHFinally.back())) {
2819 S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
2824 Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
2825 Scope *S = CurScope->getContinueParent();
2827 // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
2828 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
2830 CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);
2832 return new (Context) ContinueStmt(ContinueLoc);
2836 Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
2837 Scope *S = CurScope->getBreakParent();
2839 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
2840 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
2842 if (S->isOpenMPLoopScope())
2843 return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
2845 CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);
2847 return new (Context) BreakStmt(BreakLoc);
2850 /// \brief Determine whether the given expression is a candidate for
2851 /// copy elision in either a return statement or a throw expression.
2853 /// \param ReturnType If we're determining the copy elision candidate for
2854 /// a return statement, this is the return type of the function. If we're
2855 /// determining the copy elision candidate for a throw expression, this will
2858 /// \param E The expression being returned from the function or block, or
2861 /// \param AllowParamOrMoveConstructible Whether we allow function parameters or
2862 /// id-expressions that could be moved out of the function to be considered NRVO
2863 /// candidates. C++ prohibits these for NRVO itself, but we re-use this logic to
2864 /// determine whether we should try to move as part of a return or throw (which
2865 /// does allow function parameters).
2867 /// \returns The NRVO candidate variable, if the return statement may use the
2868 /// NRVO, or NULL if there is no such candidate.
2869 VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, Expr *E,
2870 bool AllowParamOrMoveConstructible) {
2871 if (!getLangOpts().CPlusPlus)
2874 // - in a return statement in a function [where] ...
2875 // ... the expression is the name of a non-volatile automatic object ...
2876 DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
2877 if (!DR || DR->refersToEnclosingVariableOrCapture())
2879 VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
2883 if (isCopyElisionCandidate(ReturnType, VD, AllowParamOrMoveConstructible))
2888 bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
2889 bool AllowParamOrMoveConstructible) {
2890 QualType VDType = VD->getType();
2891 // - in a return statement in a function with ...
2892 // ... a class return type ...
2893 if (!ReturnType.isNull() && !ReturnType->isDependentType()) {
2894 if (!ReturnType->isRecordType())
2896 // ... the same cv-unqualified type as the function return type ...
2897 // When considering moving this expression out, allow dissimilar types.
2898 if (!AllowParamOrMoveConstructible && !VDType->isDependentType() &&
2899 !Context.hasSameUnqualifiedType(ReturnType, VDType))
2903 // ...object (other than a function or catch-clause parameter)...
2904 if (VD->getKind() != Decl::Var &&
2905 !(AllowParamOrMoveConstructible && VD->getKind() == Decl::ParmVar))
2907 if (VD->isExceptionVariable()) return false;
2910 if (!VD->hasLocalStorage()) return false;
2912 // Return false if VD is a __block variable. We don't want to implicitly move
2913 // out of a __block variable during a return because we cannot assume the
2914 // variable will no longer be used.
2915 if (VD->hasAttr<BlocksAttr>()) return false;
2917 if (AllowParamOrMoveConstructible)
2920 // ...non-volatile...
2921 if (VD->getType().isVolatileQualified()) return false;
2923 // Variables with higher required alignment than their type's ABI
2924 // alignment cannot use NRVO.
2925 if (!VD->getType()->isDependentType() && VD->hasAttr<AlignedAttr>() &&
2926 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType()))
2932 /// \brief Perform the initialization of a potentially-movable value, which
2933 /// is the result of return value.
2935 /// This routine implements C++14 [class.copy]p32, which attempts to treat
2936 /// returned lvalues as rvalues in certain cases (to prefer move construction),
2937 /// then falls back to treating them as lvalues if that failed.
2939 Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
2940 const VarDecl *NRVOCandidate,
2941 QualType ResultType,
2944 // C++14 [class.copy]p32:
2945 // When the criteria for elision of a copy/move operation are met, but not for
2946 // an exception-declaration, and the object to be copied is designated by an
2947 // lvalue, or when the expression in a return statement is a (possibly
2948 // parenthesized) id-expression that names an object with automatic storage
2949 // duration declared in the body or parameter-declaration-clause of the
2950 // innermost enclosing function or lambda-expression, overload resolution to
2951 // select the constructor for the copy is first performed as if the object
2952 // were designated by an rvalue.
2953 ExprResult Res = ExprError();
2955 if (AllowNRVO && !NRVOCandidate)
2956 NRVOCandidate = getCopyElisionCandidate(ResultType, Value, true);
2958 if (AllowNRVO && NRVOCandidate) {
2959 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
2960 CK_NoOp, Value, VK_XValue);
2962 Expr *InitExpr = &AsRvalue;
2964 InitializationKind Kind = InitializationKind::CreateCopy(
2965 Value->getLocStart(), Value->getLocStart());
2967 InitializationSequence Seq(*this, Entity, Kind, InitExpr);
2969 for (const InitializationSequence::Step &Step : Seq.steps()) {
2971 InitializationSequence::SK_ConstructorInitialization ||
2972 (Step.Kind == InitializationSequence::SK_UserConversion &&
2973 isa<CXXConstructorDecl>(Step.Function.Function))))
2976 CXXConstructorDecl *Constructor =
2977 cast<CXXConstructorDecl>(Step.Function.Function);
2979 const RValueReferenceType *RRefType
2980 = Constructor->getParamDecl(0)->getType()
2981 ->getAs<RValueReferenceType>();
2983 // [...] If the first overload resolution fails or was not performed, or
2984 // if the type of the first parameter of the selected constructor is not
2985 // an rvalue reference to the object's type (possibly cv-qualified),
2986 // overload resolution is performed again, considering the object as an
2989 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
2990 NRVOCandidate->getType()))
2993 // Promote "AsRvalue" to the heap, since we now need this
2994 // expression node to persist.
2995 Value = ImplicitCastExpr::Create(Context, Value->getType(), CK_NoOp,
2996 Value, nullptr, VK_XValue);
2998 // Complete type-checking the initialization of the return type
2999 // using the constructor we found.
3000 Res = Seq.Perform(*this, Entity, Kind, Value);
3005 // Either we didn't meet the criteria for treating an lvalue as an rvalue,
3006 // above, or overload resolution failed. Either way, we need to try
3007 // (again) now with the return value expression as written.
3008 if (Res.isInvalid())
3009 Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
3014 /// \brief Determine whether the declared return type of the specified function
3015 /// contains 'auto'.
3016 static bool hasDeducedReturnType(FunctionDecl *FD) {
3017 const FunctionProtoType *FPT =
3018 FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
3019 return FPT->getReturnType()->isUndeducedType();
3022 /// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
3023 /// for capturing scopes.
3026 Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
3027 // If this is the first return we've seen, infer the return type.
3028 // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
3029 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
3030 QualType FnRetType = CurCap->ReturnType;
3031 LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
3032 bool HasDeducedReturnType =
3033 CurLambda && hasDeducedReturnType(CurLambda->CallOperator);
3035 if (ExprEvalContexts.back().Context ==
3036 ExpressionEvaluationContext::DiscardedStatement &&
3037 (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
3039 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3042 RetValExp = ER.get();
3044 return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3047 if (HasDeducedReturnType) {
3048 // In C++1y, the return type may involve 'auto'.
3049 // FIXME: Blocks might have a return type of 'auto' explicitly specified.
3050 FunctionDecl *FD = CurLambda->CallOperator;
3051 if (CurCap->ReturnType.isNull())
3052 CurCap->ReturnType = FD->getReturnType();
3054 AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3055 assert(AT && "lost auto type from lambda return type");
3056 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3057 FD->setInvalidDecl();
3060 CurCap->ReturnType = FnRetType = FD->getReturnType();
3061 } else if (CurCap->HasImplicitReturnType) {
3062 // For blocks/lambdas with implicit return types, we check each return
3063 // statement individually, and deduce the common return type when the block
3064 // or lambda is completed.
3065 // FIXME: Fold this into the 'auto' codepath above.
3066 if (RetValExp && !isa<InitListExpr>(RetValExp)) {
3067 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
3068 if (Result.isInvalid())
3070 RetValExp = Result.get();
3072 // DR1048: even prior to C++14, we should use the 'auto' deduction rules
3073 // when deducing a return type for a lambda-expression (or by extension
3074 // for a block). These rules differ from the stated C++11 rules only in
3075 // that they remove top-level cv-qualifiers.
3076 if (!CurContext->isDependentContext())
3077 FnRetType = RetValExp->getType().getUnqualifiedType();
3079 FnRetType = CurCap->ReturnType = Context.DependentTy;
3082 // C++11 [expr.lambda.prim]p4 bans inferring the result from an
3083 // initializer list, because it is not an expression (even
3084 // though we represent it as one). We still deduce 'void'.
3085 Diag(ReturnLoc, diag::err_lambda_return_init_list)
3086 << RetValExp->getSourceRange();
3089 FnRetType = Context.VoidTy;
3092 // Although we'll properly infer the type of the block once it's completed,
3093 // make sure we provide a return type now for better error recovery.
3094 if (CurCap->ReturnType.isNull())
3095 CurCap->ReturnType = FnRetType;
3097 assert(!FnRetType.isNull());
3099 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
3100 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
3101 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
3104 } else if (CapturedRegionScopeInfo *CurRegion =
3105 dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
3106 Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3109 assert(CurLambda && "unknown kind of captured scope");
3110 if (CurLambda->CallOperator->getType()->getAs<FunctionType>()
3111 ->getNoReturnAttr()) {
3112 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
3117 // Otherwise, verify that this result type matches the previous one. We are
3118 // pickier with blocks than for normal functions because we don't have GCC
3119 // compatibility to worry about here.
3120 const VarDecl *NRVOCandidate = nullptr;
3121 if (FnRetType->isDependentType()) {
3122 // Delay processing for now. TODO: there are lots of dependent
3123 // types we can conclusively prove aren't void.
3124 } else if (FnRetType->isVoidType()) {
3125 if (RetValExp && !isa<InitListExpr>(RetValExp) &&
3126 !(getLangOpts().CPlusPlus &&
3127 (RetValExp->isTypeDependent() ||
3128 RetValExp->getType()->isVoidType()))) {
3129 if (!getLangOpts().CPlusPlus &&
3130 RetValExp->getType()->isVoidType())
3131 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
3133 Diag(ReturnLoc, diag::err_return_block_has_expr);
3134 RetValExp = nullptr;
3137 } else if (!RetValExp) {
3138 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
3139 } else if (!RetValExp->isTypeDependent()) {
3140 // we have a non-void block with an expression, continue checking
3142 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3143 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3146 // In C++ the return statement is handled via a copy initialization.
3147 // the C version of which boils down to CheckSingleAssignmentConstraints.
3148 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3149 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
3151 NRVOCandidate != nullptr);
3152 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
3153 FnRetType, RetValExp);
3154 if (Res.isInvalid()) {
3155 // FIXME: Cleanup temporaries here, anyway?
3158 RetValExp = Res.get();
3159 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc);
3161 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3165 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3168 RetValExp = ER.get();
3170 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
3173 // If we need to check for the named return value optimization,
3174 // or if we need to infer the return type,
3175 // save the return statement in our scope for later processing.
3176 if (CurCap->HasImplicitReturnType || NRVOCandidate)
3177 FunctionScopes.back()->Returns.push_back(Result);
3179 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3180 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3186 /// \brief Marks all typedefs in all local classes in a type referenced.
3188 /// In a function like
3190 /// struct S { typedef int a; };
3194 /// the local type escapes and could be referenced in some TUs but not in
3195 /// others. Pretend that all local typedefs are always referenced, to not warn
3196 /// on this. This isn't necessary if f has internal linkage, or the typedef
3198 class LocalTypedefNameReferencer
3199 : public RecursiveASTVisitor<LocalTypedefNameReferencer> {
3201 LocalTypedefNameReferencer(Sema &S) : S(S) {}
3202 bool VisitRecordType(const RecordType *RT);
3206 bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
3207 auto *R = dyn_cast<CXXRecordDecl>(RT->getDecl());
3208 if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3209 R->isDependentType())
3211 for (auto *TmpD : R->decls())
3212 if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
3213 if (T->getAccess() != AS_private || R->hasFriends())
3214 S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
3219 TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3220 TypeLoc TL = FD->getTypeSourceInfo()->getTypeLoc().IgnoreParens();
3221 while (auto ATL = TL.getAs<AttributedTypeLoc>())
3222 TL = ATL.getModifiedLoc().IgnoreParens();
3223 return TL.castAs<FunctionProtoTypeLoc>().getReturnLoc();
3226 /// Deduce the return type for a function from a returned expression, per
3227 /// C++1y [dcl.spec.auto]p6.
3228 bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3229 SourceLocation ReturnLoc,
3232 // If this is the conversion function for a lambda, we choose to deduce it
3233 // type from the corresponding call operator, not from the synthesized return
3234 // statement within it. See Sema::DeduceReturnType.
3235 if (isLambdaConversionOperator(FD))
3238 TypeLoc OrigResultType = getReturnTypeLoc(FD);
3241 if (RetExpr && isa<InitListExpr>(RetExpr)) {
3242 // If the deduction is for a return statement and the initializer is
3243 // a braced-init-list, the program is ill-formed.
3244 Diag(RetExpr->getExprLoc(),
3245 getCurLambda() ? diag::err_lambda_return_init_list
3246 : diag::err_auto_fn_return_init_list)
3247 << RetExpr->getSourceRange();
3251 if (FD->isDependentContext()) {
3252 // C++1y [dcl.spec.auto]p12:
3253 // Return type deduction [...] occurs when the definition is
3254 // instantiated even if the function body contains a return
3255 // statement with a non-type-dependent operand.
3256 assert(AT->isDeduced() && "should have deduced to dependent type");
3261 // Otherwise, [...] deduce a value for U using the rules of template
3262 // argument deduction.
3263 DeduceAutoResult DAR = DeduceAutoType(OrigResultType, RetExpr, Deduced);
3265 if (DAR == DAR_Failed && !FD->isInvalidDecl())
3266 Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
3267 << OrigResultType.getType() << RetExpr->getType();
3269 if (DAR != DAR_Succeeded)
3272 // If a local type is part of the returned type, mark its fields as
3274 LocalTypedefNameReferencer Referencer(*this);
3275 Referencer.TraverseType(RetExpr->getType());
3277 // In the case of a return with no operand, the initializer is considered
3280 // Deduction here can only succeed if the return type is exactly 'cv auto'
3281 // or 'decltype(auto)', so just check for that case directly.
3282 if (!OrigResultType.getType()->getAs<AutoType>()) {
3283 Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
3284 << OrigResultType.getType();
3287 // We always deduce U = void in this case.
3288 Deduced = SubstAutoType(OrigResultType.getType(), Context.VoidTy);
3289 if (Deduced.isNull())
3293 // If a function with a declared return type that contains a placeholder type
3294 // has multiple return statements, the return type is deduced for each return
3295 // statement. [...] if the type deduced is not the same in each deduction,
3296 // the program is ill-formed.
3297 QualType DeducedT = AT->getDeducedType();
3298 if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
3299 AutoType *NewAT = Deduced->getContainedAutoType();
3300 // It is possible that NewAT->getDeducedType() is null. When that happens,
3301 // we should not crash, instead we ignore this deduction.
3302 if (NewAT->getDeducedType().isNull())
3305 CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
3307 CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(
3308 NewAT->getDeducedType());
3309 if (!FD->isDependentContext() && OldDeducedType != NewDeducedType) {
3310 const LambdaScopeInfo *LambdaSI = getCurLambda();
3311 if (LambdaSI && LambdaSI->HasImplicitReturnType) {
3312 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3313 << NewAT->getDeducedType() << DeducedT
3314 << true /*IsLambda*/;
3316 Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3317 << (AT->isDecltypeAuto() ? 1 : 0)
3318 << NewAT->getDeducedType() << DeducedT;
3322 } else if (!FD->isInvalidDecl()) {
3323 // Update all declarations of the function to have the deduced return type.
3324 Context.adjustDeducedFunctionResultType(FD, Deduced);
3331 Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3333 StmtResult R = BuildReturnStmt(ReturnLoc, RetValExp);
3334 if (R.isInvalid() || ExprEvalContexts.back().Context ==
3335 ExpressionEvaluationContext::DiscardedStatement)
3339 const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
3340 CurScope->addNRVOCandidate(VD);
3342 CurScope->setNoNRVO();
3345 CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
3350 StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
3351 // Check for unexpanded parameter packs.
3352 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
3355 if (isa<CapturingScopeInfo>(getCurFunction()))
3356 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
3359 QualType RelatedRetType;
3360 const AttrVec *Attrs = nullptr;
3361 bool isObjCMethod = false;
3363 if (const FunctionDecl *FD = getCurFunctionDecl()) {
3364 FnRetType = FD->getReturnType();
3366 Attrs = &FD->getAttrs();
3367 if (FD->isNoReturn())
3368 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
3369 << FD->getDeclName();
3370 if (FD->isMain() && RetValExp)
3371 if (isa<CXXBoolLiteralExpr>(RetValExp))
3372 Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
3373 << RetValExp->getSourceRange();
3374 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3375 FnRetType = MD->getReturnType();
3376 isObjCMethod = true;
3378 Attrs = &MD->getAttrs();
3379 if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3380 // In the implementation of a method with a related return type, the
3381 // type used to type-check the validity of return statements within the
3382 // method body is a pointer to the type of the class being implemented.
3383 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
3384 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
3386 } else // If we don't have a function/method context, bail.
3389 // C++1z: discarded return statements are not considered when deducing a
3391 if (ExprEvalContexts.back().Context ==
3392 ExpressionEvaluationContext::DiscardedStatement &&
3393 FnRetType->getContainedAutoType()) {
3395 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3398 RetValExp = ER.get();
3400 return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3403 // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3405 if (getLangOpts().CPlusPlus14) {
3406 if (AutoType *AT = FnRetType->getContainedAutoType()) {
3407 FunctionDecl *FD = cast<FunctionDecl>(CurContext);
3408 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3409 FD->setInvalidDecl();
3412 FnRetType = FD->getReturnType();
3417 bool HasDependentReturnType = FnRetType->isDependentType();
3419 ReturnStmt *Result = nullptr;
3420 if (FnRetType->isVoidType()) {
3422 if (isa<InitListExpr>(RetValExp)) {
3423 // We simply never allow init lists as the return value of void
3424 // functions. This is compatible because this was never allowed before,
3425 // so there's no legacy code to deal with.
3426 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3427 int FunctionKind = 0;
3428 if (isa<ObjCMethodDecl>(CurDecl))
3430 else if (isa<CXXConstructorDecl>(CurDecl))
3432 else if (isa<CXXDestructorDecl>(CurDecl))
3435 Diag(ReturnLoc, diag::err_return_init_list)
3436 << CurDecl->getDeclName() << FunctionKind
3437 << RetValExp->getSourceRange();
3439 // Drop the expression.
3440 RetValExp = nullptr;
3441 } else if (!RetValExp->isTypeDependent()) {
3442 // C99 6.8.6.4p1 (ext_ since GCC warns)
3443 unsigned D = diag::ext_return_has_expr;
3444 if (RetValExp->getType()->isVoidType()) {
3445 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3446 if (isa<CXXConstructorDecl>(CurDecl) ||
3447 isa<CXXDestructorDecl>(CurDecl))
3448 D = diag::err_ctor_dtor_returns_void;
3450 D = diag::ext_return_has_void_expr;
3453 ExprResult Result = RetValExp;
3454 Result = IgnoredValueConversions(Result.get());
3455 if (Result.isInvalid())
3457 RetValExp = Result.get();
3458 RetValExp = ImpCastExprToType(RetValExp,
3459 Context.VoidTy, CK_ToVoid).get();
3461 // return of void in constructor/destructor is illegal in C++.
3462 if (D == diag::err_ctor_dtor_returns_void) {
3463 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3465 << CurDecl->getDeclName() << isa<CXXDestructorDecl>(CurDecl)
3466 << RetValExp->getSourceRange();
3468 // return (some void expression); is legal in C++.
3469 else if (D != diag::ext_return_has_void_expr ||
3470 !getLangOpts().CPlusPlus) {
3471 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3473 int FunctionKind = 0;
3474 if (isa<ObjCMethodDecl>(CurDecl))
3476 else if (isa<CXXConstructorDecl>(CurDecl))
3478 else if (isa<CXXDestructorDecl>(CurDecl))
3482 << CurDecl->getDeclName() << FunctionKind
3483 << RetValExp->getSourceRange();
3488 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3491 RetValExp = ER.get();
3495 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3496 } else if (!RetValExp && !HasDependentReturnType) {
3497 FunctionDecl *FD = getCurFunctionDecl();
3500 if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
3501 // C++11 [stmt.return]p2
3502 DiagID = diag::err_constexpr_return_missing_expr;
3503 FD->setInvalidDecl();
3504 } else if (getLangOpts().C99) {
3505 // C99 6.8.6.4p1 (ext_ since GCC warns)
3506 DiagID = diag::ext_return_missing_expr;
3509 DiagID = diag::warn_return_missing_expr;
3513 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
3515 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
3517 Result = new (Context) ReturnStmt(ReturnLoc);
3519 assert(RetValExp || HasDependentReturnType);
3520 const VarDecl *NRVOCandidate = nullptr;
3522 QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
3524 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3525 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3528 // In C++ the return statement is handled via a copy initialization,
3529 // the C version of which boils down to CheckSingleAssignmentConstraints.
3531 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3532 if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
3533 // we have a non-void function with an expression, continue checking
3534 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
3536 NRVOCandidate != nullptr);
3537 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
3538 RetType, RetValExp);
3539 if (Res.isInvalid()) {
3540 // FIXME: Clean up temporaries here anyway?
3543 RetValExp = Res.getAs<Expr>();
3545 // If we have a related result type, we need to implicitly
3546 // convert back to the formal result type. We can't pretend to
3547 // initialize the result again --- we might end double-retaining
3548 // --- so instead we initialize a notional temporary.
3549 if (!RelatedRetType.isNull()) {
3550 Entity = InitializedEntity::InitializeRelatedResult(getCurMethodDecl(),
3552 Res = PerformCopyInitialization(Entity, ReturnLoc, RetValExp);
3553 if (Res.isInvalid()) {
3554 // FIXME: Clean up temporaries here anyway?
3557 RetValExp = Res.getAs<Expr>();
3560 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc, isObjCMethod, Attrs,
3561 getCurFunctionDecl());
3565 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3568 RetValExp = ER.get();
3570 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
3573 // If we need to check for the named return value optimization, save the
3574 // return statement in our scope for later processing.
3575 if (Result->getNRVOCandidate())
3576 FunctionScopes.back()->Returns.push_back(Result);
3578 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3579 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3585 Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
3586 SourceLocation RParen, Decl *Parm,
3588 VarDecl *Var = cast_or_null<VarDecl>(Parm);
3589 if (Var && Var->isInvalidDecl())
3592 return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
3596 Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
3597 return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
3601 Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
3602 MultiStmtArg CatchStmts, Stmt *Finally) {
3603 if (!getLangOpts().ObjCExceptions)
3604 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
3606 getCurFunction()->setHasBranchProtectedScope();
3607 unsigned NumCatchStmts = CatchStmts.size();
3608 return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),
3609 NumCatchStmts, Finally);
3612 StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
3614 ExprResult Result = DefaultLvalueConversion(Throw);
3615 if (Result.isInvalid())
3618 Result = ActOnFinishFullExpr(Result.get());
3619 if (Result.isInvalid())
3621 Throw = Result.get();
3623 QualType ThrowType = Throw->getType();
3624 // Make sure the expression type is an ObjC pointer or "void *".
3625 if (!ThrowType->isDependentType() &&
3626 !ThrowType->isObjCObjectPointerType()) {
3627 const PointerType *PT = ThrowType->getAs<PointerType>();
3628 if (!PT || !PT->getPointeeType()->isVoidType())
3629 return StmtError(Diag(AtLoc, diag::err_objc_throw_expects_object)
3630 << Throw->getType() << Throw->getSourceRange());
3634 return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
3638 Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
3640 if (!getLangOpts().ObjCExceptions)
3641 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
3644 // @throw without an expression designates a rethrow (which must occur
3645 // in the context of an @catch clause).
3646 Scope *AtCatchParent = CurScope;
3647 while (AtCatchParent && !AtCatchParent->isAtCatchScope())
3648 AtCatchParent = AtCatchParent->getParent();
3650 return StmtError(Diag(AtLoc, diag::err_rethrow_used_outside_catch));
3652 return BuildObjCAtThrowStmt(AtLoc, Throw);
3656 Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
3657 ExprResult result = DefaultLvalueConversion(operand);
3658 if (result.isInvalid())
3660 operand = result.get();
3662 // Make sure the expression type is an ObjC pointer or "void *".
3663 QualType type = operand->getType();
3664 if (!type->isDependentType() &&
3665 !type->isObjCObjectPointerType()) {
3666 const PointerType *pointerType = type->getAs<PointerType>();
3667 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) {
3668 if (getLangOpts().CPlusPlus) {
3669 if (RequireCompleteType(atLoc, type,
3670 diag::err_incomplete_receiver_type))
3671 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3672 << type << operand->getSourceRange();
3674 ExprResult result = PerformContextuallyConvertToObjCPointer(operand);
3675 if (result.isInvalid())
3677 if (!result.isUsable())
3678 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3679 << type << operand->getSourceRange();
3681 operand = result.get();
3683 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3684 << type << operand->getSourceRange();
3689 // The operand to @synchronized is a full-expression.
3690 return ActOnFinishFullExpr(operand);
3694 Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
3696 // We can't jump into or indirect-jump out of a @synchronized block.
3697 getCurFunction()->setHasBranchProtectedScope();
3698 return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
3701 /// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
3702 /// and creates a proper catch handler from them.
3704 Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
3705 Stmt *HandlerBlock) {
3706 // There's nothing to test that ActOnExceptionDecl didn't already test.
3707 return new (Context)
3708 CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(ExDecl), HandlerBlock);
3712 Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
3713 getCurFunction()->setHasBranchProtectedScope();
3714 return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
3718 class CatchHandlerType {
3720 unsigned IsPointer : 1;
3722 // This is a special constructor to be used only with DenseMapInfo's
3723 // getEmptyKey() and getTombstoneKey() functions.
3724 friend struct llvm::DenseMapInfo<CatchHandlerType>;
3725 enum Unique { ForDenseMap };
3726 CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
3729 /// Used when creating a CatchHandlerType from a handler type; will determine
3730 /// whether the type is a pointer or reference and will strip off the top
3731 /// level pointer and cv-qualifiers.
3732 CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
3733 if (QT->isPointerType())
3736 if (IsPointer || QT->isReferenceType())
3737 QT = QT->getPointeeType();
3738 QT = QT.getUnqualifiedType();
3741 /// Used when creating a CatchHandlerType from a base class type; pretends the
3742 /// type passed in had the pointer qualifier, does not need to get an
3743 /// unqualified type.
3744 CatchHandlerType(QualType QT, bool IsPointer)
3745 : QT(QT), IsPointer(IsPointer) {}
3747 QualType underlying() const { return QT; }
3748 bool isPointer() const { return IsPointer; }
3750 friend bool operator==(const CatchHandlerType &LHS,
3751 const CatchHandlerType &RHS) {
3752 // If the pointer qualification does not match, we can return early.
3753 if (LHS.IsPointer != RHS.IsPointer)
3755 // Otherwise, check the underlying type without cv-qualifiers.
3756 return LHS.QT == RHS.QT;
3762 template <> struct DenseMapInfo<CatchHandlerType> {
3763 static CatchHandlerType getEmptyKey() {
3764 return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
3765 CatchHandlerType::ForDenseMap);
3768 static CatchHandlerType getTombstoneKey() {
3769 return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
3770 CatchHandlerType::ForDenseMap);
3773 static unsigned getHashValue(const CatchHandlerType &Base) {
3774 return DenseMapInfo<QualType>::getHashValue(Base.underlying());
3777 static bool isEqual(const CatchHandlerType &LHS,
3778 const CatchHandlerType &RHS) {
3785 class CatchTypePublicBases {
3787 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &TypesToCheck;
3788 const bool CheckAgainstPointer;
3790 CXXCatchStmt *FoundHandler;
3791 CanQualType FoundHandlerType;
3794 CatchTypePublicBases(
3796 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &T, bool C)
3797 : Ctx(Ctx), TypesToCheck(T), CheckAgainstPointer(C),
3798 FoundHandler(nullptr) {}
3800 CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
3801 CanQualType getFoundHandlerType() const { return FoundHandlerType; }
3803 bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
3804 if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
3805 CatchHandlerType Check(S->getType(), CheckAgainstPointer);
3806 const auto &M = TypesToCheck;
3807 auto I = M.find(Check);
3809 FoundHandler = I->second;
3810 FoundHandlerType = Ctx.getCanonicalType(S->getType());
3819 /// ActOnCXXTryBlock - Takes a try compound-statement and a number of
3820 /// handlers and creates a try statement from them.
3821 StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
3822 ArrayRef<Stmt *> Handlers) {
3823 // Don't report an error if 'try' is used in system headers.
3824 if (!getLangOpts().CXXExceptions &&
3825 !getSourceManager().isInSystemHeader(TryLoc))
3826 Diag(TryLoc, diag::err_exceptions_disabled) << "try";
3828 // Exceptions aren't allowed in CUDA device code.
3829 if (getLangOpts().CUDA)
3830 CUDADiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
3831 << "try" << CurrentCUDATarget();
3833 if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
3834 Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
3836 sema::FunctionScopeInfo *FSI = getCurFunction();
3838 // C++ try is incompatible with SEH __try.
3839 if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
3840 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3841 Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
3844 const unsigned NumHandlers = Handlers.size();
3845 assert(!Handlers.empty() &&
3846 "The parser shouldn't call this if there are no handlers.");
3848 llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
3849 for (unsigned i = 0; i < NumHandlers; ++i) {
3850 CXXCatchStmt *H = cast<CXXCatchStmt>(Handlers[i]);
3852 // Diagnose when the handler is a catch-all handler, but it isn't the last
3853 // handler for the try block. [except.handle]p5. Also, skip exception
3854 // declarations that are invalid, since we can't usefully report on them.
3855 if (!H->getExceptionDecl()) {
3856 if (i < NumHandlers - 1)
3857 return StmtError(Diag(H->getLocStart(), diag::err_early_catch_all));
3859 } else if (H->getExceptionDecl()->isInvalidDecl())
3862 // Walk the type hierarchy to diagnose when this type has already been
3863 // handled (duplication), or cannot be handled (derivation inversion). We
3864 // ignore top-level cv-qualifiers, per [except.handle]p3
3865 CatchHandlerType HandlerCHT =
3866 (QualType)Context.getCanonicalType(H->getCaughtType());
3868 // We can ignore whether the type is a reference or a pointer; we need the
3869 // underlying declaration type in order to get at the underlying record
3870 // decl, if there is one.
3871 QualType Underlying = HandlerCHT.underlying();
3872 if (auto *RD = Underlying->getAsCXXRecordDecl()) {
3873 if (!RD->hasDefinition())
3875 // Check that none of the public, unambiguous base classes are in the
3876 // map ([except.handle]p1). Give the base classes the same pointer
3877 // qualification as the original type we are basing off of. This allows
3878 // comparison against the handler type using the same top-level pointer
3879 // as the original type.
3881 Paths.setOrigin(RD);
3882 CatchTypePublicBases CTPB(Context, HandledTypes, HandlerCHT.isPointer());
3883 if (RD->lookupInBases(CTPB, Paths)) {
3884 const CXXCatchStmt *Problem = CTPB.getFoundHandler();
3885 if (!Paths.isAmbiguous(CTPB.getFoundHandlerType())) {
3886 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3887 diag::warn_exception_caught_by_earlier_handler)
3888 << H->getCaughtType();
3889 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3890 diag::note_previous_exception_handler)
3891 << Problem->getCaughtType();
3896 // Add the type the list of ones we have handled; diagnose if we've already
3898 auto R = HandledTypes.insert(std::make_pair(H->getCaughtType(), H));
3900 const CXXCatchStmt *Problem = R.first->second;
3901 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3902 diag::warn_exception_caught_by_earlier_handler)
3903 << H->getCaughtType();
3904 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3905 diag::note_previous_exception_handler)
3906 << Problem->getCaughtType();
3910 FSI->setHasCXXTry(TryLoc);
3912 return CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers);
3915 StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
3916 Stmt *TryBlock, Stmt *Handler) {
3917 assert(TryBlock && Handler);
3919 sema::FunctionScopeInfo *FSI = getCurFunction();
3921 // SEH __try is incompatible with C++ try. Borland appears to support this,
3923 if (!getLangOpts().Borland) {
3924 if (FSI->FirstCXXTryLoc.isValid()) {
3925 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3926 Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
3930 FSI->setHasSEHTry(TryLoc);
3932 // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
3933 // track if they use SEH.
3934 DeclContext *DC = CurContext;
3935 while (DC && !DC->isFunctionOrMethod())
3936 DC = DC->getParent();
3937 FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
3939 FD->setUsesSEHTry(true);
3941 Diag(TryLoc, diag::err_seh_try_outside_functions);
3943 // Reject __try on unsupported targets.
3944 if (!Context.getTargetInfo().isSEHTrySupported())
3945 Diag(TryLoc, diag::err_seh_try_unsupported);
3947 return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
3951 Sema::ActOnSEHExceptBlock(SourceLocation Loc,
3954 assert(FilterExpr && Block);
3956 if(!FilterExpr->getType()->isIntegerType()) {
3957 return StmtError(Diag(FilterExpr->getExprLoc(),
3958 diag::err_filter_expression_integral)
3959 << FilterExpr->getType());
3962 return SEHExceptStmt::Create(Context,Loc,FilterExpr,Block);
3965 void Sema::ActOnStartSEHFinallyBlock() {
3966 CurrentSEHFinally.push_back(CurScope);
3969 void Sema::ActOnAbortSEHFinallyBlock() {
3970 CurrentSEHFinally.pop_back();
3973 StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
3975 CurrentSEHFinally.pop_back();
3976 return SEHFinallyStmt::Create(Context, Loc, Block);
3980 Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
3981 Scope *SEHTryParent = CurScope;
3982 while (SEHTryParent && !SEHTryParent->isSEHTryScope())
3983 SEHTryParent = SEHTryParent->getParent();
3985 return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
3986 CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);
3988 return new (Context) SEHLeaveStmt(Loc);
3991 StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
3993 NestedNameSpecifierLoc QualifierLoc,
3994 DeclarationNameInfo NameInfo,
3997 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
3998 QualifierLoc, NameInfo,
3999 cast<CompoundStmt>(Nested));
4003 StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4006 UnqualifiedId &Name,
4008 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4009 SS.getWithLocInContext(Context),
4010 GetNameFromUnqualifiedId(Name),
4015 Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4016 unsigned NumParams) {
4017 DeclContext *DC = CurContext;
4018 while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4019 DC = DC->getParent();
4021 RecordDecl *RD = nullptr;
4022 if (getLangOpts().CPlusPlus)
4023 RD = CXXRecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc,
4026 RD = RecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc, /*Id=*/nullptr);
4028 RD->setCapturedRecord();
4031 RD->startDefinition();
4033 assert(NumParams > 0 && "CapturedStmt requires context parameter");
4034 CD = CapturedDecl::Create(Context, CurContext, NumParams);
4039 static void buildCapturedStmtCaptureList(
4040 SmallVectorImpl<CapturedStmt::Capture> &Captures,
4041 SmallVectorImpl<Expr *> &CaptureInits,
4042 ArrayRef<CapturingScopeInfo::Capture> Candidates) {
4044 typedef ArrayRef<CapturingScopeInfo::Capture>::const_iterator CaptureIter;
4045 for (CaptureIter Cap = Candidates.begin(); Cap != Candidates.end(); ++Cap) {
4047 if (Cap->isThisCapture()) {
4048 Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
4049 CapturedStmt::VCK_This));
4050 CaptureInits.push_back(Cap->getInitExpr());
4052 } else if (Cap->isVLATypeCapture()) {
4054 CapturedStmt::Capture(Cap->getLocation(), CapturedStmt::VCK_VLAType));
4055 CaptureInits.push_back(nullptr);
4059 Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
4060 Cap->isReferenceCapture()
4061 ? CapturedStmt::VCK_ByRef
4062 : CapturedStmt::VCK_ByCopy,
4063 Cap->getVariable()));
4064 CaptureInits.push_back(Cap->getInitExpr());
4068 void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4069 CapturedRegionKind Kind,
4070 unsigned NumParams) {
4071 CapturedDecl *CD = nullptr;
4072 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4074 // Build the context parameter
4075 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4076 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4077 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4079 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4080 ImplicitParamDecl::CapturedContext);
4083 CD->setContextParam(0, Param);
4085 // Enter the capturing scope for this captured region.
4086 PushCapturedRegionScope(CurScope, CD, RD, Kind);
4089 PushDeclContext(CurScope, CD);
4093 PushExpressionEvaluationContext(
4094 ExpressionEvaluationContext::PotentiallyEvaluated);
4097 void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4098 CapturedRegionKind Kind,
4099 ArrayRef<CapturedParamNameType> Params) {
4100 CapturedDecl *CD = nullptr;
4101 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, Params.size());
4103 // Build the context parameter
4104 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4105 bool ContextIsFound = false;
4106 unsigned ParamNum = 0;
4107 for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4109 I != E; ++I, ++ParamNum) {
4110 if (I->second.isNull()) {
4111 assert(!ContextIsFound &&
4112 "null type has been found already for '__context' parameter");
4113 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4114 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4116 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4117 ImplicitParamDecl::CapturedContext);
4119 CD->setContextParam(ParamNum, Param);
4120 ContextIsFound = true;
4122 IdentifierInfo *ParamName = &Context.Idents.get(I->first);
4124 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
4125 ImplicitParamDecl::CapturedContext);
4127 CD->setParam(ParamNum, Param);
4130 assert(ContextIsFound && "no null type for '__context' parameter");
4131 if (!ContextIsFound) {
4132 // Add __context implicitly if it is not specified.
4133 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4134 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4136 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4137 ImplicitParamDecl::CapturedContext);
4139 CD->setContextParam(ParamNum, Param);
4141 // Enter the capturing scope for this captured region.
4142 PushCapturedRegionScope(CurScope, CD, RD, Kind);
4145 PushDeclContext(CurScope, CD);
4149 PushExpressionEvaluationContext(
4150 ExpressionEvaluationContext::PotentiallyEvaluated);
4153 void Sema::ActOnCapturedRegionError() {
4154 DiscardCleanupsInEvaluationContext();
4155 PopExpressionEvaluationContext();
4157 CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
4158 RecordDecl *Record = RSI->TheRecordDecl;
4159 Record->setInvalidDecl();
4161 SmallVector<Decl*, 4> Fields(Record->fields());
4162 ActOnFields(/*Scope=*/nullptr, Record->getLocation(), Record, Fields,
4163 SourceLocation(), SourceLocation(), /*AttributeList=*/nullptr);
4166 PopFunctionScopeInfo();
4169 StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4170 CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
4172 SmallVector<CapturedStmt::Capture, 4> Captures;
4173 SmallVector<Expr *, 4> CaptureInits;
4174 buildCapturedStmtCaptureList(Captures, CaptureInits, RSI->Captures);
4176 CapturedDecl *CD = RSI->TheCapturedDecl;
4177 RecordDecl *RD = RSI->TheRecordDecl;
4179 CapturedStmt *Res = CapturedStmt::Create(
4180 getASTContext(), S, static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4181 Captures, CaptureInits, CD, RD);
4183 CD->setBody(Res->getCapturedStmt());
4184 RD->completeDefinition();
4186 DiscardCleanupsInEvaluationContext();
4187 PopExpressionEvaluationContext();
4190 PopFunctionScopeInfo();