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/CharUnits.h"
18 #include "clang/AST/CXXInheritance.h"
19 #include "clang/AST/DeclObjC.h"
20 #include "clang/AST/EvaluatedExprVisitor.h"
21 #include "clang/AST/ExprCXX.h"
22 #include "clang/AST/ExprObjC.h"
23 #include "clang/AST/RecursiveASTVisitor.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/StmtObjC.h"
26 #include "clang/AST/TypeLoc.h"
27 #include "clang/AST/TypeOrdering.h"
28 #include "clang/Basic/TargetInfo.h"
29 #include "clang/Lex/Preprocessor.h"
30 #include "clang/Sema/Initialization.h"
31 #include "clang/Sema/Lookup.h"
32 #include "clang/Sema/Scope.h"
33 #include "clang/Sema/ScopeInfo.h"
34 #include "llvm/ADT/ArrayRef.h"
35 #include "llvm/ADT/DenseMap.h"
36 #include "llvm/ADT/STLExtras.h"
37 #include "llvm/ADT/SmallPtrSet.h"
38 #include "llvm/ADT/SmallString.h"
39 #include "llvm/ADT/SmallVector.h"
41 using namespace clang;
44 StmtResult Sema::ActOnExprStmt(ExprResult FE) {
48 FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(),
49 /*DiscardedValue*/ true);
53 // C99 6.8.3p2: The expression in an expression statement is evaluated as a
54 // void expression for its side effects. Conversion to void allows any
55 // operand, even incomplete types.
57 // Same thing in for stmt first clause (when expr) and third clause.
58 return StmtResult(FE.getAs<Stmt>());
62 StmtResult Sema::ActOnExprStmtError() {
63 DiscardCleanupsInEvaluationContext();
67 StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
68 bool HasLeadingEmptyMacro) {
69 return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
72 StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
73 SourceLocation EndLoc) {
74 DeclGroupRef DG = dg.get();
76 // If we have an invalid decl, just return an error.
77 if (DG.isNull()) return StmtError();
79 return new (Context) DeclStmt(DG, StartLoc, EndLoc);
82 void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
83 DeclGroupRef DG = dg.get();
85 // If we don't have a declaration, or we have an invalid declaration,
87 if (DG.isNull() || !DG.isSingleDecl())
90 Decl *decl = DG.getSingleDecl();
91 if (!decl || decl->isInvalidDecl())
94 // Only variable declarations are permitted.
95 VarDecl *var = dyn_cast<VarDecl>(decl);
97 Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
98 decl->setInvalidDecl();
102 // foreach variables are never actually initialized in the way that
103 // the parser came up with.
104 var->setInit(nullptr);
106 // In ARC, we don't need to retain the iteration variable of a fast
107 // enumeration loop. Rather than actually trying to catch that
108 // during declaration processing, we remove the consequences here.
109 if (getLangOpts().ObjCAutoRefCount) {
110 QualType type = var->getType();
112 // Only do this if we inferred the lifetime. Inferred lifetime
113 // will show up as a local qualifier because explicit lifetime
114 // should have shown up as an AttributedType instead.
115 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
116 // Add 'const' and mark the variable as pseudo-strong.
117 var->setType(type.withConst());
118 var->setARCPseudoStrong(true);
123 /// \brief Diagnose unused comparisons, both builtin and overloaded operators.
124 /// For '==' and '!=', suggest fixits for '=' or '|='.
126 /// Adding a cast to void (or other expression wrappers) will prevent the
127 /// warning from firing.
128 static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
130 bool IsNotEqual, CanAssign, IsRelational;
132 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) {
133 if (!Op->isComparisonOp())
136 IsRelational = Op->isRelationalOp();
137 Loc = Op->getOperatorLoc();
138 IsNotEqual = Op->getOpcode() == BO_NE;
139 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
140 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) {
141 switch (Op->getOperator()) {
145 case OO_ExclaimEqual:
146 IsRelational = false;
150 case OO_GreaterEqual:
156 Loc = Op->getOperatorLoc();
157 IsNotEqual = Op->getOperator() == OO_ExclaimEqual;
158 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
160 // Not a typo-prone comparison.
164 // Suppress warnings when the operator, suspicious as it may be, comes from
165 // a macro expansion.
166 if (S.SourceMgr.isMacroBodyExpansion(Loc))
169 S.Diag(Loc, diag::warn_unused_comparison)
170 << (unsigned)IsRelational << (unsigned)IsNotEqual << E->getSourceRange();
172 // If the LHS is a plausible entity to assign to, provide a fixit hint to
173 // correct common typos.
174 if (!IsRelational && CanAssign) {
176 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
177 << FixItHint::CreateReplacement(Loc, "|=");
179 S.Diag(Loc, diag::note_equality_comparison_to_assign)
180 << FixItHint::CreateReplacement(Loc, "=");
186 void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
187 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
188 return DiagnoseUnusedExprResult(Label->getSubStmt());
190 const Expr *E = dyn_cast_or_null<Expr>(S);
194 // If we are in an unevaluated expression context, then there can be no unused
195 // results because the results aren't expected to be used in the first place.
196 if (isUnevaluatedContext())
199 SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
200 // In most cases, we don't want to warn if the expression is written in a
201 // macro body, or if the macro comes from a system header. If the offending
202 // expression is a call to a function with the warn_unused_result attribute,
203 // we warn no matter the location. Because of the order in which the various
204 // checks need to happen, we factor out the macro-related test here.
205 bool ShouldSuppress =
206 SourceMgr.isMacroBodyExpansion(ExprLoc) ||
207 SourceMgr.isInSystemMacro(ExprLoc);
209 const Expr *WarnExpr;
212 if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context))
215 // If this is a GNU statement expression expanded from a macro, it is probably
216 // unused because it is a function-like macro that can be used as either an
217 // expression or statement. Don't warn, because it is almost certainly a
219 if (isa<StmtExpr>(E) && Loc.isMacroID())
222 // Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
223 // That macro is frequently used to suppress "unused parameter" warnings,
224 // but its implementation makes clang's -Wunused-value fire. Prevent this.
225 if (isa<ParenExpr>(E->IgnoreImpCasts()) && Loc.isMacroID()) {
226 SourceLocation SpellLoc = Loc;
227 if (findMacroSpelling(SpellLoc, "UNREFERENCED_PARAMETER"))
231 // Okay, we have an unused result. Depending on what the base expression is,
232 // we might want to make a more specific diagnostic. Check for one of these
234 unsigned DiagID = diag::warn_unused_expr;
235 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E))
236 E = Temps->getSubExpr();
237 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E))
238 E = TempExpr->getSubExpr();
240 if (DiagnoseUnusedComparison(*this, E))
244 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
245 if (E->getType()->isVoidType())
248 // If the callee has attribute pure, const, or warn_unused_result, warn with
249 // a more specific message to make it clear what is happening. If the call
250 // is written in a macro body, only warn if it has the warn_unused_result
252 if (const Decl *FD = CE->getCalleeDecl()) {
253 if (const Attr *A = isa<FunctionDecl>(FD)
254 ? cast<FunctionDecl>(FD)->getUnusedResultAttr()
255 : FD->getAttr<WarnUnusedResultAttr>()) {
256 Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
261 if (FD->hasAttr<PureAttr>()) {
262 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
265 if (FD->hasAttr<ConstAttr>()) {
266 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
270 } else if (ShouldSuppress)
273 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
274 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
275 Diag(Loc, diag::err_arc_unused_init_message) << R1;
278 const ObjCMethodDecl *MD = ME->getMethodDecl();
280 if (const auto *A = MD->getAttr<WarnUnusedResultAttr>()) {
281 Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
285 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) {
286 const Expr *Source = POE->getSyntacticForm();
287 if (isa<ObjCSubscriptRefExpr>(Source))
288 DiagID = diag::warn_unused_container_subscript_expr;
290 DiagID = diag::warn_unused_property_expr;
291 } else if (const CXXFunctionalCastExpr *FC
292 = dyn_cast<CXXFunctionalCastExpr>(E)) {
293 const Expr *E = FC->getSubExpr();
294 if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(E))
295 E = TE->getSubExpr();
296 if (isa<CXXTemporaryObjectExpr>(E))
298 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E))
299 if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
300 if (!RD->getAttr<WarnUnusedAttr>())
303 // Diagnose "(void*) blah" as a typo for "(void) blah".
304 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
305 TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
306 QualType T = TI->getType();
308 // We really do want to use the non-canonical type here.
309 if (T == Context.VoidPtrTy) {
310 PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
312 Diag(Loc, diag::warn_unused_voidptr)
313 << FixItHint::CreateRemoval(TL.getStarLoc());
318 if (E->isGLValue() && E->getType().isVolatileQualified()) {
319 Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
323 DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
326 void Sema::ActOnStartOfCompoundStmt() {
330 void Sema::ActOnFinishOfCompoundStmt() {
334 sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
335 return getCurFunction()->CompoundScopes.back();
338 StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
339 ArrayRef<Stmt *> Elts, bool isStmtExpr) {
340 const unsigned NumElts = Elts.size();
342 // If we're in C89 mode, check that we don't have any decls after stmts. If
343 // so, emit an extension diagnostic.
344 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) {
345 // Note that __extension__ can be around a decl.
347 // Skip over all declarations.
348 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
351 // We found the end of the list or a statement. Scan for another declstmt.
352 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
356 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
357 Diag(D->getLocation(), diag::ext_mixed_decls_code);
360 // Warn about unused expressions in statements.
361 for (unsigned i = 0; i != NumElts; ++i) {
362 // Ignore statements that are last in a statement expression.
363 if (isStmtExpr && i == NumElts - 1)
366 DiagnoseUnusedExprResult(Elts[i]);
369 // Check for suspicious empty body (null statement) in `for' and `while'
370 // statements. Don't do anything for template instantiations, this just adds
372 if (NumElts != 0 && !CurrentInstantiationScope &&
373 getCurCompoundScope().HasEmptyLoopBodies) {
374 for (unsigned i = 0; i != NumElts - 1; ++i)
375 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]);
378 return new (Context) CompoundStmt(Context, Elts, L, R);
382 Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
383 SourceLocation DotDotDotLoc, Expr *RHSVal,
384 SourceLocation ColonLoc) {
385 assert(LHSVal && "missing expression in case statement");
387 if (getCurFunction()->SwitchStack.empty()) {
388 Diag(CaseLoc, diag::err_case_not_in_switch);
393 CorrectDelayedTyposInExpr(LHSVal, [this](class Expr *E) {
394 if (!getLangOpts().CPlusPlus11)
395 return VerifyIntegerConstantExpression(E);
397 getCurFunction()->SwitchStack.back()->getCond()) {
398 QualType CondType = CondExpr->getType();
399 llvm::APSInt TempVal;
400 return CheckConvertedConstantExpression(E, CondType, TempVal,
409 if (!getLangOpts().CPlusPlus11) {
410 // C99 6.8.4.2p3: The expression shall be an integer constant.
411 // However, GCC allows any evaluatable integer expression.
412 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) {
413 LHSVal = VerifyIntegerConstantExpression(LHSVal).get();
418 // GCC extension: The expression shall be an integer constant.
420 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) {
421 RHSVal = VerifyIntegerConstantExpression(RHSVal).get();
422 // Recover from an error by just forgetting about it.
426 LHS = ActOnFinishFullExpr(LHSVal, LHSVal->getExprLoc(), false,
427 getLangOpts().CPlusPlus11);
431 auto RHS = RHSVal ? ActOnFinishFullExpr(RHSVal, RHSVal->getExprLoc(), false,
432 getLangOpts().CPlusPlus11)
437 CaseStmt *CS = new (Context)
438 CaseStmt(LHS.get(), RHS.get(), CaseLoc, DotDotDotLoc, ColonLoc);
439 getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
443 /// ActOnCaseStmtBody - This installs a statement as the body of a case.
444 void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
445 DiagnoseUnusedExprResult(SubStmt);
447 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
448 CS->setSubStmt(SubStmt);
452 Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
453 Stmt *SubStmt, Scope *CurScope) {
454 DiagnoseUnusedExprResult(SubStmt);
456 if (getCurFunction()->SwitchStack.empty()) {
457 Diag(DefaultLoc, diag::err_default_not_in_switch);
461 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
462 getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
467 Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
468 SourceLocation ColonLoc, Stmt *SubStmt) {
469 // If the label was multiply defined, reject it now.
470 if (TheDecl->getStmt()) {
471 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
472 Diag(TheDecl->getLocation(), diag::note_previous_definition);
476 // Otherwise, things are good. Fill in the declaration and return it.
477 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
478 TheDecl->setStmt(LS);
479 if (!TheDecl->isGnuLocal()) {
480 TheDecl->setLocStart(IdentLoc);
481 if (!TheDecl->isMSAsmLabel()) {
482 // Don't update the location of MS ASM labels. These will result in
483 // a diagnostic, and changing the location here will mess that up.
484 TheDecl->setLocation(IdentLoc);
490 StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
491 ArrayRef<const Attr*> Attrs,
493 // Fill in the declaration and return it.
494 AttributedStmt *LS = AttributedStmt::Create(Context, AttrLoc, Attrs, SubStmt);
499 class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
500 typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
503 CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
504 void VisitBinaryOperator(BinaryOperator *E) {
505 if (E->getOpcode() == BO_Comma)
506 SemaRef.DiagnoseCommaOperator(E->getLHS(), E->getExprLoc());
507 EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
513 Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
514 ConditionResult Cond,
515 Stmt *thenStmt, SourceLocation ElseLoc,
517 if (Cond.isInvalid())
518 Cond = ConditionResult(
520 MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
521 Context.BoolTy, VK_RValue),
525 Expr *CondExpr = Cond.get().second;
526 if (!Diags.isIgnored(diag::warn_comma_operator,
527 CondExpr->getExprLoc()))
528 CommaVisitor(*this).Visit(CondExpr);
531 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), thenStmt,
532 diag::warn_empty_if_body);
534 return BuildIfStmt(IfLoc, IsConstexpr, InitStmt, Cond, thenStmt, ElseLoc,
538 StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
539 Stmt *InitStmt, ConditionResult Cond,
540 Stmt *thenStmt, SourceLocation ElseLoc,
542 if (Cond.isInvalid())
545 if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
546 getCurFunction()->setHasBranchProtectedScope();
548 DiagnoseUnusedExprResult(thenStmt);
549 DiagnoseUnusedExprResult(elseStmt);
552 IfStmt(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
553 Cond.get().second, thenStmt, ElseLoc, elseStmt);
557 struct CaseCompareFunctor {
558 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
559 const llvm::APSInt &RHS) {
560 return LHS.first < RHS;
562 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
563 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
564 return LHS.first < RHS.first;
566 bool operator()(const llvm::APSInt &LHS,
567 const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
568 return LHS < RHS.first;
573 /// CmpCaseVals - Comparison predicate for sorting case values.
575 static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
576 const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
577 if (lhs.first < rhs.first)
580 if (lhs.first == rhs.first &&
581 lhs.second->getCaseLoc().getRawEncoding()
582 < rhs.second->getCaseLoc().getRawEncoding())
587 /// CmpEnumVals - Comparison predicate for sorting enumeration values.
589 static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
590 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
592 return lhs.first < rhs.first;
595 /// EqEnumVals - Comparison preficate for uniqing enumeration values.
597 static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
598 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
600 return lhs.first == rhs.first;
603 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
604 /// potentially integral-promoted expression @p expr.
605 static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
606 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr))
607 expr = cleanups->getSubExpr();
608 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) {
609 if (impcast->getCastKind() != CK_IntegralCast) break;
610 expr = impcast->getSubExpr();
612 return expr->getType();
615 ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
616 class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
620 SwitchConvertDiagnoser(Expr *Cond)
621 : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
624 SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
625 QualType T) override {
626 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
629 SemaDiagnosticBuilder diagnoseIncomplete(
630 Sema &S, SourceLocation Loc, QualType T) override {
631 return S.Diag(Loc, diag::err_switch_incomplete_class_type)
632 << T << Cond->getSourceRange();
635 SemaDiagnosticBuilder diagnoseExplicitConv(
636 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
637 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
640 SemaDiagnosticBuilder noteExplicitConv(
641 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
642 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
643 << ConvTy->isEnumeralType() << ConvTy;
646 SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
647 QualType T) override {
648 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
651 SemaDiagnosticBuilder noteAmbiguous(
652 Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
653 return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
654 << ConvTy->isEnumeralType() << ConvTy;
657 SemaDiagnosticBuilder diagnoseConversion(
658 Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
659 llvm_unreachable("conversion functions are permitted");
661 } SwitchDiagnoser(Cond);
663 ExprResult CondResult =
664 PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
665 if (CondResult.isInvalid())
668 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
669 return UsualUnaryConversions(CondResult.get());
672 StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
673 Stmt *InitStmt, ConditionResult Cond) {
674 if (Cond.isInvalid())
677 getCurFunction()->setHasBranchIntoScope();
679 SwitchStmt *SS = new (Context)
680 SwitchStmt(Context, InitStmt, Cond.get().first, Cond.get().second);
681 getCurFunction()->SwitchStack.push_back(SS);
685 static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
686 Val = Val.extOrTrunc(BitWidth);
687 Val.setIsSigned(IsSigned);
690 /// Check the specified case value is in range for the given unpromoted switch
692 static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
693 unsigned UnpromotedWidth, bool UnpromotedSign) {
694 // If the case value was signed and negative and the switch expression is
695 // unsigned, don't bother to warn: this is implementation-defined behavior.
696 // FIXME: Introduce a second, default-ignored warning for this case?
697 if (UnpromotedWidth < Val.getBitWidth()) {
698 llvm::APSInt ConvVal(Val);
699 AdjustAPSInt(ConvVal, UnpromotedWidth, UnpromotedSign);
700 AdjustAPSInt(ConvVal, Val.getBitWidth(), Val.isSigned());
701 // FIXME: Use different diagnostics for overflow in conversion to promoted
702 // type versus "switch expression cannot have this value". Use proper
703 // IntRange checking rather than just looking at the unpromoted type here.
705 S.Diag(Loc, diag::warn_case_value_overflow) << Val.toString(10)
706 << ConvVal.toString(10);
710 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
712 /// Returns true if we should emit a diagnostic about this case expression not
713 /// being a part of the enum used in the switch controlling expression.
714 static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
716 const Expr *CaseExpr,
717 EnumValsTy::iterator &EI,
718 EnumValsTy::iterator &EIEnd,
719 const llvm::APSInt &Val) {
723 if (const DeclRefExpr *DRE =
724 dyn_cast<DeclRefExpr>(CaseExpr->IgnoreParenImpCasts())) {
725 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
726 QualType VarType = VD->getType();
727 QualType EnumType = S.Context.getTypeDeclType(ED);
728 if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
729 S.Context.hasSameUnqualifiedType(EnumType, VarType))
734 if (ED->hasAttr<FlagEnumAttr>())
735 return !S.IsValueInFlagEnum(ED, Val, false);
737 while (EI != EIEnd && EI->first < Val)
740 if (EI != EIEnd && EI->first == Val)
747 Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
749 SwitchStmt *SS = cast<SwitchStmt>(Switch);
750 assert(SS == getCurFunction()->SwitchStack.back() &&
751 "switch stack missing push/pop!");
753 getCurFunction()->SwitchStack.pop_back();
755 if (!BodyStmt) return StmtError();
756 SS->setBody(BodyStmt, SwitchLoc);
758 Expr *CondExpr = SS->getCond();
759 if (!CondExpr) return StmtError();
761 QualType CondType = CondExpr->getType();
763 Expr *CondExprBeforePromotion = CondExpr;
764 QualType CondTypeBeforePromotion =
765 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
768 // Integral promotions are performed (on the switch condition).
770 // A case value unrepresentable by the original switch condition
771 // type (before the promotion) doesn't make sense, even when it can
772 // be represented by the promoted type. Therefore we need to find
773 // the pre-promotion type of the switch condition.
774 if (!CondExpr->isTypeDependent()) {
775 // We have already converted the expression to an integral or enumeration
776 // type, when we started the switch statement. If we don't have an
777 // appropriate type now, just return an error.
778 if (!CondType->isIntegralOrEnumerationType())
781 if (CondExpr->isKnownToHaveBooleanValue()) {
782 // switch(bool_expr) {...} is often a programmer error, e.g.
783 // switch(n && mask) { ... } // Doh - should be "n & mask".
784 // One can always use an if statement instead of switch(bool_expr).
785 Diag(SwitchLoc, diag::warn_bool_switch_condition)
786 << CondExpr->getSourceRange();
790 // Get the bitwidth of the switched-on value after promotions. We must
791 // convert the integer case values to this width before comparison.
792 bool HasDependentValue
793 = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
794 unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(CondType);
795 bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
797 // Get the width and signedness that the condition might actually have, for
799 // FIXME: Grab an IntRange for the condition rather than using the unpromoted
801 unsigned CondWidthBeforePromotion
802 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion);
803 bool CondIsSignedBeforePromotion
804 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
806 // Accumulate all of the case values in a vector so that we can sort them
807 // and detect duplicates. This vector contains the APInt for the case after
808 // it has been converted to the condition type.
809 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
812 // Keep track of any GNU case ranges we see. The APSInt is the low value.
813 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
814 CaseRangesTy CaseRanges;
816 DefaultStmt *TheDefaultStmt = nullptr;
818 bool CaseListIsErroneous = false;
820 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
821 SC = SC->getNextSwitchCase()) {
823 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
824 if (TheDefaultStmt) {
825 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
826 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
828 // FIXME: Remove the default statement from the switch block so that
829 // we'll return a valid AST. This requires recursing down the AST and
830 // finding it, not something we are set up to do right now. For now,
831 // just lop the entire switch stmt out of the AST.
832 CaseListIsErroneous = true;
837 CaseStmt *CS = cast<CaseStmt>(SC);
839 Expr *Lo = CS->getLHS();
841 if (Lo->isTypeDependent() || Lo->isValueDependent()) {
842 HasDependentValue = true;
848 if (getLangOpts().CPlusPlus11) {
849 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
850 // constant expression of the promoted type of the switch condition.
852 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue);
853 if (ConvLo.isInvalid()) {
854 CaseListIsErroneous = true;
859 // We already verified that the expression has a i-c-e value (C99
860 // 6.8.4.2p3) - get that value now.
861 LoVal = Lo->EvaluateKnownConstInt(Context);
863 // If the LHS is not the same type as the condition, insert an implicit
865 Lo = DefaultLvalueConversion(Lo).get();
866 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).get();
869 // Check the unconverted value is within the range of possible values of
870 // the switch expression.
871 checkCaseValue(*this, Lo->getLocStart(), LoVal,
872 CondWidthBeforePromotion, CondIsSignedBeforePromotion);
874 // Convert the value to the same width/sign as the condition.
875 AdjustAPSInt(LoVal, CondWidth, CondIsSigned);
879 // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
881 if (CS->getRHS()->isTypeDependent() ||
882 CS->getRHS()->isValueDependent()) {
883 HasDependentValue = true;
886 CaseRanges.push_back(std::make_pair(LoVal, CS));
888 CaseVals.push_back(std::make_pair(LoVal, CS));
892 if (!HasDependentValue) {
893 // If we don't have a default statement, check whether the
894 // condition is constant.
895 llvm::APSInt ConstantCondValue;
896 bool HasConstantCond = false;
897 if (!HasDependentValue && !TheDefaultStmt) {
898 HasConstantCond = CondExpr->EvaluateAsInt(ConstantCondValue, Context,
899 Expr::SE_AllowSideEffects);
900 assert(!HasConstantCond ||
901 (ConstantCondValue.getBitWidth() == CondWidth &&
902 ConstantCondValue.isSigned() == CondIsSigned));
904 bool ShouldCheckConstantCond = HasConstantCond;
906 // Sort all the scalar case values so we can easily detect duplicates.
907 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
909 if (!CaseVals.empty()) {
910 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
911 if (ShouldCheckConstantCond &&
912 CaseVals[i].first == ConstantCondValue)
913 ShouldCheckConstantCond = false;
915 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
916 // If we have a duplicate, report it.
917 // First, determine if either case value has a name
918 StringRef PrevString, CurrString;
919 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
920 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
921 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) {
922 PrevString = DeclRef->getDecl()->getName();
924 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) {
925 CurrString = DeclRef->getDecl()->getName();
927 SmallString<16> CaseValStr;
928 CaseVals[i-1].first.toString(CaseValStr);
930 if (PrevString == CurrString)
931 Diag(CaseVals[i].second->getLHS()->getLocStart(),
932 diag::err_duplicate_case) <<
933 (PrevString.empty() ? StringRef(CaseValStr) : PrevString);
935 Diag(CaseVals[i].second->getLHS()->getLocStart(),
936 diag::err_duplicate_case_differing_expr) <<
937 (PrevString.empty() ? StringRef(CaseValStr) : PrevString) <<
938 (CurrString.empty() ? StringRef(CaseValStr) : CurrString) <<
941 Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
942 diag::note_duplicate_case_prev);
943 // FIXME: We really want to remove the bogus case stmt from the
944 // substmt, but we have no way to do this right now.
945 CaseListIsErroneous = true;
950 // Detect duplicate case ranges, which usually don't exist at all in
952 if (!CaseRanges.empty()) {
953 // Sort all the case ranges by their low value so we can easily detect
954 // overlaps between ranges.
955 std::stable_sort(CaseRanges.begin(), CaseRanges.end());
957 // Scan the ranges, computing the high values and removing empty ranges.
958 std::vector<llvm::APSInt> HiVals;
959 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
960 llvm::APSInt &LoVal = CaseRanges[i].first;
961 CaseStmt *CR = CaseRanges[i].second;
962 Expr *Hi = CR->getRHS();
965 if (getLangOpts().CPlusPlus11) {
966 // C++11 [stmt.switch]p2: the constant-expression shall be a converted
967 // constant expression of the promoted type of the switch condition.
969 CheckConvertedConstantExpression(Hi, CondType, HiVal,
971 if (ConvHi.isInvalid()) {
972 CaseListIsErroneous = true;
977 HiVal = Hi->EvaluateKnownConstInt(Context);
979 // If the RHS is not the same type as the condition, insert an
981 Hi = DefaultLvalueConversion(Hi).get();
982 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).get();
985 // Check the unconverted value is within the range of possible values of
986 // the switch expression.
987 checkCaseValue(*this, Hi->getLocStart(), HiVal,
988 CondWidthBeforePromotion, CondIsSignedBeforePromotion);
990 // Convert the value to the same width/sign as the condition.
991 AdjustAPSInt(HiVal, CondWidth, CondIsSigned);
995 // If the low value is bigger than the high value, the case is empty.
997 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
998 << SourceRange(CR->getLHS()->getLocStart(),
1000 CaseRanges.erase(CaseRanges.begin()+i);
1006 if (ShouldCheckConstantCond &&
1007 LoVal <= ConstantCondValue &&
1008 ConstantCondValue <= HiVal)
1009 ShouldCheckConstantCond = false;
1011 HiVals.push_back(HiVal);
1014 // Rescan the ranges, looking for overlap with singleton values and other
1015 // ranges. Since the range list is sorted, we only need to compare case
1016 // ranges with their neighbors.
1017 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1018 llvm::APSInt &CRLo = CaseRanges[i].first;
1019 llvm::APSInt &CRHi = HiVals[i];
1020 CaseStmt *CR = CaseRanges[i].second;
1022 // Check to see whether the case range overlaps with any
1024 CaseStmt *OverlapStmt = nullptr;
1025 llvm::APSInt OverlapVal(32);
1027 // Find the smallest value >= the lower bound. If I is in the
1028 // case range, then we have overlap.
1029 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
1030 CaseVals.end(), CRLo,
1031 CaseCompareFunctor());
1032 if (I != CaseVals.end() && I->first < CRHi) {
1033 OverlapVal = I->first; // Found overlap with scalar.
1034 OverlapStmt = I->second;
1037 // Find the smallest value bigger than the upper bound.
1038 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
1039 if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1040 OverlapVal = (I-1)->first; // Found overlap with scalar.
1041 OverlapStmt = (I-1)->second;
1044 // Check to see if this case stmt overlaps with the subsequent
1046 if (i && CRLo <= HiVals[i-1]) {
1047 OverlapVal = HiVals[i-1]; // Found overlap with range.
1048 OverlapStmt = CaseRanges[i-1].second;
1052 // If we have a duplicate, report it.
1053 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
1054 << OverlapVal.toString(10);
1055 Diag(OverlapStmt->getLHS()->getLocStart(),
1056 diag::note_duplicate_case_prev);
1057 // FIXME: We really want to remove the bogus case stmt from the
1058 // substmt, but we have no way to do this right now.
1059 CaseListIsErroneous = true;
1064 // Complain if we have a constant condition and we didn't find a match.
1065 if (!CaseListIsErroneous && ShouldCheckConstantCond) {
1066 // TODO: it would be nice if we printed enums as enums, chars as
1068 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1069 << ConstantCondValue.toString(10)
1070 << CondExpr->getSourceRange();
1073 // Check to see if switch is over an Enum and handles all of its
1074 // values. We only issue a warning if there is not 'default:', but
1075 // we still do the analysis to preserve this information in the AST
1076 // (which can be used by flow-based analyes).
1078 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1080 // If switch has default case, then ignore it.
1081 if (!CaseListIsErroneous && !HasConstantCond && ET &&
1082 ET->getDecl()->isCompleteDefinition()) {
1083 const EnumDecl *ED = ET->getDecl();
1084 EnumValsTy EnumVals;
1086 // Gather all enum values, set their type and sort them,
1087 // allowing easier comparison with CaseVals.
1088 for (auto *EDI : ED->enumerators()) {
1089 llvm::APSInt Val = EDI->getInitVal();
1090 AdjustAPSInt(Val, CondWidth, CondIsSigned);
1091 EnumVals.push_back(std::make_pair(Val, EDI));
1093 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1094 auto EI = EnumVals.begin(), EIEnd =
1095 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1097 // See which case values aren't in enum.
1098 for (CaseValsTy::const_iterator CI = CaseVals.begin();
1099 CI != CaseVals.end(); CI++) {
1100 Expr *CaseExpr = CI->second->getLHS();
1101 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1103 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1104 << CondTypeBeforePromotion;
1107 // See which of case ranges aren't in enum
1108 EI = EnumVals.begin();
1109 for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1110 RI != CaseRanges.end(); RI++) {
1111 Expr *CaseExpr = RI->second->getLHS();
1112 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1114 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1115 << CondTypeBeforePromotion;
1118 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1119 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1121 CaseExpr = RI->second->getRHS();
1122 if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1124 Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1125 << CondTypeBeforePromotion;
1128 // Check which enum vals aren't in switch
1129 auto CI = CaseVals.begin();
1130 auto RI = CaseRanges.begin();
1131 bool hasCasesNotInSwitch = false;
1133 SmallVector<DeclarationName,8> UnhandledNames;
1135 for (EI = EnumVals.begin(); EI != EIEnd; EI++){
1136 // Drop unneeded case values
1137 while (CI != CaseVals.end() && CI->first < EI->first)
1140 if (CI != CaseVals.end() && CI->first == EI->first)
1143 // Drop unneeded case ranges
1144 for (; RI != CaseRanges.end(); RI++) {
1146 RI->second->getRHS()->EvaluateKnownConstInt(Context);
1147 AdjustAPSInt(Hi, CondWidth, CondIsSigned);
1148 if (EI->first <= Hi)
1152 if (RI == CaseRanges.end() || EI->first < RI->first) {
1153 hasCasesNotInSwitch = true;
1154 UnhandledNames.push_back(EI->second->getDeclName());
1158 if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1159 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1161 // Produce a nice diagnostic if multiple values aren't handled.
1162 if (!UnhandledNames.empty()) {
1163 DiagnosticBuilder DB = Diag(CondExpr->getExprLoc(),
1164 TheDefaultStmt ? diag::warn_def_missing_case
1165 : diag::warn_missing_case)
1166 << (int)UnhandledNames.size();
1168 for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
1170 DB << UnhandledNames[I];
1173 if (!hasCasesNotInSwitch)
1174 SS->setAllEnumCasesCovered();
1179 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt,
1180 diag::warn_empty_switch_body);
1182 // FIXME: If the case list was broken is some way, we don't have a good system
1183 // to patch it up. Instead, just return the whole substmt as broken.
1184 if (CaseListIsErroneous)
1191 Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1193 if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1196 if (const EnumType *ET = DstType->getAs<EnumType>())
1197 if (!Context.hasSameUnqualifiedType(SrcType, DstType) &&
1198 SrcType->isIntegerType()) {
1199 if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
1200 SrcExpr->isIntegerConstantExpr(Context)) {
1201 // Get the bitwidth of the enum value before promotions.
1202 unsigned DstWidth = Context.getIntWidth(DstType);
1203 bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1205 llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Context);
1206 AdjustAPSInt(RhsVal, DstWidth, DstIsSigned);
1207 const EnumDecl *ED = ET->getDecl();
1209 if (!ED->isClosed())
1212 if (ED->hasAttr<FlagEnumAttr>()) {
1213 if (!IsValueInFlagEnum(ED, RhsVal, true))
1214 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1215 << DstType.getUnqualifiedType();
1217 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1219 EnumValsTy EnumVals;
1221 // Gather all enum values, set their type and sort them,
1222 // allowing easier comparison with rhs constant.
1223 for (auto *EDI : ED->enumerators()) {
1224 llvm::APSInt Val = EDI->getInitVal();
1225 AdjustAPSInt(Val, DstWidth, DstIsSigned);
1226 EnumVals.push_back(std::make_pair(Val, EDI));
1228 if (EnumVals.empty())
1230 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
1231 EnumValsTy::iterator EIend =
1232 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
1234 // See which values aren't in the enum.
1235 EnumValsTy::const_iterator EI = EnumVals.begin();
1236 while (EI != EIend && EI->first < RhsVal)
1238 if (EI == EIend || EI->first != RhsVal) {
1239 Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1240 << DstType.getUnqualifiedType();
1247 StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
1249 if (Cond.isInvalid())
1252 auto CondVal = Cond.get();
1253 CheckBreakContinueBinding(CondVal.second);
1255 if (CondVal.second &&
1256 !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
1257 CommaVisitor(*this).Visit(CondVal.second);
1259 DiagnoseUnusedExprResult(Body);
1261 if (isa<NullStmt>(Body))
1262 getCurCompoundScope().setHasEmptyLoopBodies();
1264 return new (Context)
1265 WhileStmt(Context, CondVal.first, CondVal.second, Body, WhileLoc);
1269 Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1270 SourceLocation WhileLoc, SourceLocation CondLParen,
1271 Expr *Cond, SourceLocation CondRParen) {
1272 assert(Cond && "ActOnDoStmt(): missing expression");
1274 CheckBreakContinueBinding(Cond);
1275 ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
1276 if (CondResult.isInvalid())
1278 Cond = CondResult.get();
1280 CondResult = ActOnFinishFullExpr(Cond, DoLoc);
1281 if (CondResult.isInvalid())
1283 Cond = CondResult.get();
1285 DiagnoseUnusedExprResult(Body);
1287 return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1291 // Use SetVector since the diagnostic cares about the ordering of the Decl's.
1292 using DeclSetVector =
1293 llvm::SetVector<VarDecl *, llvm::SmallVector<VarDecl *, 8>,
1294 llvm::SmallPtrSet<VarDecl *, 8>>;
1296 // This visitor will traverse a conditional statement and store all
1297 // the evaluated decls into a vector. Simple is set to true if none
1298 // of the excluded constructs are used.
1299 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1300 DeclSetVector &Decls;
1301 SmallVectorImpl<SourceRange> &Ranges;
1304 typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1306 DeclExtractor(Sema &S, DeclSetVector &Decls,
1307 SmallVectorImpl<SourceRange> &Ranges) :
1308 Inherited(S.Context),
1313 bool isSimple() { return Simple; }
1315 // Replaces the method in EvaluatedExprVisitor.
1316 void VisitMemberExpr(MemberExpr* E) {
1320 // Any Stmt not whitelisted will cause the condition to be marked complex.
1321 void VisitStmt(Stmt *S) {
1325 void VisitBinaryOperator(BinaryOperator *E) {
1330 void VisitCastExpr(CastExpr *E) {
1331 Visit(E->getSubExpr());
1334 void VisitUnaryOperator(UnaryOperator *E) {
1335 // Skip checking conditionals with derefernces.
1336 if (E->getOpcode() == UO_Deref)
1339 Visit(E->getSubExpr());
1342 void VisitConditionalOperator(ConditionalOperator *E) {
1343 Visit(E->getCond());
1344 Visit(E->getTrueExpr());
1345 Visit(E->getFalseExpr());
1348 void VisitParenExpr(ParenExpr *E) {
1349 Visit(E->getSubExpr());
1352 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1353 Visit(E->getOpaqueValue()->getSourceExpr());
1354 Visit(E->getFalseExpr());
1357 void VisitIntegerLiteral(IntegerLiteral *E) { }
1358 void VisitFloatingLiteral(FloatingLiteral *E) { }
1359 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1360 void VisitCharacterLiteral(CharacterLiteral *E) { }
1361 void VisitGNUNullExpr(GNUNullExpr *E) { }
1362 void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1364 void VisitDeclRefExpr(DeclRefExpr *E) {
1365 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
1368 Ranges.push_back(E->getSourceRange());
1373 }; // end class DeclExtractor
1375 // DeclMatcher checks to see if the decls are used in a non-evaluated
1377 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1378 DeclSetVector &Decls;
1382 typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1384 DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1385 Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1386 if (!Statement) return;
1391 void VisitReturnStmt(ReturnStmt *S) {
1395 void VisitBreakStmt(BreakStmt *S) {
1399 void VisitGotoStmt(GotoStmt *S) {
1403 void VisitCastExpr(CastExpr *E) {
1404 if (E->getCastKind() == CK_LValueToRValue)
1405 CheckLValueToRValueCast(E->getSubExpr());
1407 Visit(E->getSubExpr());
1410 void CheckLValueToRValueCast(Expr *E) {
1411 E = E->IgnoreParenImpCasts();
1413 if (isa<DeclRefExpr>(E)) {
1417 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
1418 Visit(CO->getCond());
1419 CheckLValueToRValueCast(CO->getTrueExpr());
1420 CheckLValueToRValueCast(CO->getFalseExpr());
1424 if (BinaryConditionalOperator *BCO =
1425 dyn_cast<BinaryConditionalOperator>(E)) {
1426 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
1427 CheckLValueToRValueCast(BCO->getFalseExpr());
1434 void VisitDeclRefExpr(DeclRefExpr *E) {
1435 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
1436 if (Decls.count(VD))
1440 void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
1441 // Only need to visit the semantics for POE.
1442 // SyntaticForm doesn't really use the Decal.
1443 for (auto *S : POE->semantics()) {
1444 if (auto *OVE = dyn_cast<OpaqueValueExpr>(S))
1445 // Look past the OVE into the expression it binds.
1446 Visit(OVE->getSourceExpr());
1452 bool FoundDeclInUse() { return FoundDecl; }
1454 }; // end class DeclMatcher
1456 void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
1457 Expr *Third, Stmt *Body) {
1458 // Condition is empty
1459 if (!Second) return;
1461 if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
1462 Second->getLocStart()))
1465 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
1466 DeclSetVector Decls;
1467 SmallVector<SourceRange, 10> Ranges;
1468 DeclExtractor DE(S, Decls, Ranges);
1471 // Don't analyze complex conditionals.
1472 if (!DE.isSimple()) return;
1475 if (Decls.size() == 0) return;
1477 // Don't warn on volatile, static, or global variables.
1478 for (auto *VD : Decls)
1479 if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
1482 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
1483 DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
1484 DeclMatcher(S, Decls, Body).FoundDeclInUse())
1487 // Load decl names into diagnostic.
1488 if (Decls.size() > 4) {
1491 PDiag << (unsigned)Decls.size();
1492 for (auto *VD : Decls)
1493 PDiag << VD->getDeclName();
1496 for (auto Range : Ranges)
1499 S.Diag(Ranges.begin()->getBegin(), PDiag);
1502 // If Statement is an incemement or decrement, return true and sets the
1503 // variables Increment and DRE.
1504 bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
1505 DeclRefExpr *&DRE) {
1506 if (auto Cleanups = dyn_cast<ExprWithCleanups>(Statement))
1507 if (!Cleanups->cleanupsHaveSideEffects())
1508 Statement = Cleanups->getSubExpr();
1510 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
1511 switch (UO->getOpcode()) {
1512 default: return false;
1522 DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr());
1526 if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Statement)) {
1527 FunctionDecl *FD = Call->getDirectCallee();
1528 if (!FD || !FD->isOverloadedOperator()) return false;
1529 switch (FD->getOverloadedOperator()) {
1530 default: return false;
1538 DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
1545 // A visitor to determine if a continue or break statement is a
1547 class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
1548 SourceLocation BreakLoc;
1549 SourceLocation ContinueLoc;
1550 bool InSwitch = false;
1553 BreakContinueFinder(Sema &S, const Stmt* Body) :
1554 Inherited(S.Context) {
1558 typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
1560 void VisitContinueStmt(const ContinueStmt* E) {
1561 ContinueLoc = E->getContinueLoc();
1564 void VisitBreakStmt(const BreakStmt* E) {
1566 BreakLoc = E->getBreakLoc();
1569 void VisitSwitchStmt(const SwitchStmt* S) {
1570 if (const Stmt *Init = S->getInit())
1572 if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
1574 if (const Stmt *Cond = S->getCond())
1577 // Don't return break statements from the body of a switch.
1579 if (const Stmt *Body = S->getBody())
1584 void VisitForStmt(const ForStmt *S) {
1585 // Only visit the init statement of a for loop; the body
1586 // has a different break/continue scope.
1587 if (const Stmt *Init = S->getInit())
1591 void VisitWhileStmt(const WhileStmt *) {
1592 // Do nothing; the children of a while loop have a different
1593 // break/continue scope.
1596 void VisitDoStmt(const DoStmt *) {
1597 // Do nothing; the children of a while loop have a different
1598 // break/continue scope.
1601 void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
1602 // Only visit the initialization of a for loop; the body
1603 // has a different break/continue scope.
1604 if (const Stmt *Range = S->getRangeStmt())
1606 if (const Stmt *Begin = S->getBeginStmt())
1608 if (const Stmt *End = S->getEndStmt())
1612 void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
1613 // Only visit the initialization of a for loop; the body
1614 // has a different break/continue scope.
1615 if (const Stmt *Element = S->getElement())
1617 if (const Stmt *Collection = S->getCollection())
1621 bool ContinueFound() { return ContinueLoc.isValid(); }
1622 bool BreakFound() { return BreakLoc.isValid(); }
1623 SourceLocation GetContinueLoc() { return ContinueLoc; }
1624 SourceLocation GetBreakLoc() { return BreakLoc; }
1626 }; // end class BreakContinueFinder
1628 // Emit a warning when a loop increment/decrement appears twice per loop
1629 // iteration. The conditions which trigger this warning are:
1630 // 1) The last statement in the loop body and the third expression in the
1631 // for loop are both increment or both decrement of the same variable
1632 // 2) No continue statements in the loop body.
1633 void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
1634 // Return when there is nothing to check.
1635 if (!Body || !Third) return;
1637 if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
1638 Third->getLocStart()))
1641 // Get the last statement from the loop body.
1642 CompoundStmt *CS = dyn_cast<CompoundStmt>(Body);
1643 if (!CS || CS->body_empty()) return;
1644 Stmt *LastStmt = CS->body_back();
1645 if (!LastStmt) return;
1647 bool LoopIncrement, LastIncrement;
1648 DeclRefExpr *LoopDRE, *LastDRE;
1650 if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
1651 if (!ProcessIterationStmt(S, LastStmt, LastIncrement, LastDRE)) return;
1653 // Check that the two statements are both increments or both decrements
1654 // on the same variable.
1655 if (LoopIncrement != LastIncrement ||
1656 LoopDRE->getDecl() != LastDRE->getDecl()) return;
1658 if (BreakContinueFinder(S, Body).ContinueFound()) return;
1660 S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
1661 << LastDRE->getDecl() << LastIncrement;
1662 S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
1669 void Sema::CheckBreakContinueBinding(Expr *E) {
1670 if (!E || getLangOpts().CPlusPlus)
1672 BreakContinueFinder BCFinder(*this, E);
1673 Scope *BreakParent = CurScope->getBreakParent();
1674 if (BCFinder.BreakFound() && BreakParent) {
1675 if (BreakParent->getFlags() & Scope::SwitchScope) {
1676 Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
1678 Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
1681 } else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
1682 Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
1687 StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
1688 Stmt *First, ConditionResult Second,
1689 FullExprArg third, SourceLocation RParenLoc,
1691 if (Second.isInvalid())
1694 if (!getLangOpts().CPlusPlus) {
1695 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
1696 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1697 // declare identifiers for objects having storage class 'auto' or
1699 for (auto *DI : DS->decls()) {
1700 VarDecl *VD = dyn_cast<VarDecl>(DI);
1701 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
1704 Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
1705 DI->setInvalidDecl();
1711 CheckBreakContinueBinding(Second.get().second);
1712 CheckBreakContinueBinding(third.get());
1714 if (!Second.get().first)
1715 CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
1717 CheckForRedundantIteration(*this, third.get(), Body);
1719 if (Second.get().second &&
1720 !Diags.isIgnored(diag::warn_comma_operator,
1721 Second.get().second->getExprLoc()))
1722 CommaVisitor(*this).Visit(Second.get().second);
1724 Expr *Third = third.release().getAs<Expr>();
1726 DiagnoseUnusedExprResult(First);
1727 DiagnoseUnusedExprResult(Third);
1728 DiagnoseUnusedExprResult(Body);
1730 if (isa<NullStmt>(Body))
1731 getCurCompoundScope().setHasEmptyLoopBodies();
1733 return new (Context)
1734 ForStmt(Context, First, Second.get().second, Second.get().first, Third,
1735 Body, ForLoc, LParenLoc, RParenLoc);
1738 /// In an Objective C collection iteration statement:
1740 /// x can be an arbitrary l-value expression. Bind it up as a
1741 /// full-expression.
1742 StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
1743 // Reduce placeholder expressions here. Note that this rejects the
1744 // use of pseudo-object l-values in this position.
1745 ExprResult result = CheckPlaceholderExpr(E);
1746 if (result.isInvalid()) return StmtError();
1749 ExprResult FullExpr = ActOnFinishFullExpr(E);
1750 if (FullExpr.isInvalid())
1752 return StmtResult(static_cast<Stmt*>(FullExpr.get()));
1756 Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
1760 ExprResult result = CorrectDelayedTyposInExpr(collection);
1761 if (!result.isUsable())
1763 collection = result.get();
1765 // Bail out early if we've got a type-dependent expression.
1766 if (collection->isTypeDependent()) return collection;
1768 // Perform normal l-value conversion.
1769 result = DefaultFunctionArrayLvalueConversion(collection);
1770 if (result.isInvalid())
1772 collection = result.get();
1774 // The operand needs to have object-pointer type.
1775 // TODO: should we do a contextual conversion?
1776 const ObjCObjectPointerType *pointerType =
1777 collection->getType()->getAs<ObjCObjectPointerType>();
1779 return Diag(forLoc, diag::err_collection_expr_type)
1780 << collection->getType() << collection->getSourceRange();
1782 // Check that the operand provides
1783 // - countByEnumeratingWithState:objects:count:
1784 const ObjCObjectType *objectType = pointerType->getObjectType();
1785 ObjCInterfaceDecl *iface = objectType->getInterface();
1787 // If we have a forward-declared type, we can't do this check.
1788 // Under ARC, it is an error not to have a forward-declared class.
1790 (getLangOpts().ObjCAutoRefCount
1791 ? RequireCompleteType(forLoc, QualType(objectType, 0),
1792 diag::err_arc_collection_forward, collection)
1793 : !isCompleteType(forLoc, QualType(objectType, 0)))) {
1794 // Otherwise, if we have any useful type information, check that
1795 // the type declares the appropriate method.
1796 } else if (iface || !objectType->qual_empty()) {
1797 IdentifierInfo *selectorIdents[] = {
1798 &Context.Idents.get("countByEnumeratingWithState"),
1799 &Context.Idents.get("objects"),
1800 &Context.Idents.get("count")
1802 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]);
1804 ObjCMethodDecl *method = nullptr;
1806 // If there's an interface, look in both the public and private APIs.
1808 method = iface->lookupInstanceMethod(selector);
1809 if (!method) method = iface->lookupPrivateMethod(selector);
1812 // Also check protocol qualifiers.
1814 method = LookupMethodInQualifiedType(selector, pointerType,
1817 // If we didn't find it anywhere, give up.
1819 Diag(forLoc, diag::warn_collection_expr_type)
1820 << collection->getType() << selector << collection->getSourceRange();
1823 // TODO: check for an incompatible signature?
1826 // Wrap up any cleanups in the expression.
1831 Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
1832 Stmt *First, Expr *collection,
1833 SourceLocation RParenLoc) {
1834 getCurFunction()->setHasBranchProtectedScope();
1836 ExprResult CollectionExprResult =
1837 CheckObjCForCollectionOperand(ForLoc, collection);
1841 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
1842 if (!DS->isSingleDecl())
1843 return StmtError(Diag((*DS->decl_begin())->getLocation(),
1844 diag::err_toomany_element_decls));
1846 VarDecl *D = dyn_cast<VarDecl>(DS->getSingleDecl());
1847 if (!D || D->isInvalidDecl())
1850 FirstType = D->getType();
1851 // C99 6.8.5p3: The declaration part of a 'for' statement shall only
1852 // declare identifiers for objects having storage class 'auto' or
1854 if (!D->hasLocalStorage())
1855 return StmtError(Diag(D->getLocation(),
1856 diag::err_non_local_variable_decl_in_for));
1858 // If the type contained 'auto', deduce the 'auto' to 'id'.
1859 if (FirstType->getContainedAutoType()) {
1860 OpaqueValueExpr OpaqueId(D->getLocation(), Context.getObjCIdType(),
1862 Expr *DeducedInit = &OpaqueId;
1863 if (DeduceAutoType(D->getTypeSourceInfo(), DeducedInit, FirstType) ==
1865 DiagnoseAutoDeductionFailure(D, DeducedInit);
1866 if (FirstType.isNull()) {
1867 D->setInvalidDecl();
1871 D->setType(FirstType);
1873 if (!inTemplateInstantiation()) {
1874 SourceLocation Loc =
1875 D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
1876 Diag(Loc, diag::warn_auto_var_is_id)
1877 << D->getDeclName();
1882 Expr *FirstE = cast<Expr>(First);
1883 if (!FirstE->isTypeDependent() && !FirstE->isLValue())
1884 return StmtError(Diag(First->getLocStart(),
1885 diag::err_selector_element_not_lvalue)
1886 << First->getSourceRange());
1888 FirstType = static_cast<Expr*>(First)->getType();
1889 if (FirstType.isConstQualified())
1890 Diag(ForLoc, diag::err_selector_element_const_type)
1891 << FirstType << First->getSourceRange();
1893 if (!FirstType->isDependentType() &&
1894 !FirstType->isObjCObjectPointerType() &&
1895 !FirstType->isBlockPointerType())
1896 return StmtError(Diag(ForLoc, diag::err_selector_element_type)
1897 << FirstType << First->getSourceRange());
1900 if (CollectionExprResult.isInvalid())
1903 CollectionExprResult = ActOnFinishFullExpr(CollectionExprResult.get());
1904 if (CollectionExprResult.isInvalid())
1907 return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
1908 nullptr, ForLoc, RParenLoc);
1911 /// Finish building a variable declaration for a for-range statement.
1912 /// \return true if an error occurs.
1913 static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
1914 SourceLocation Loc, int DiagID) {
1915 if (Decl->getType()->isUndeducedType()) {
1916 ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
1917 if (!Res.isUsable()) {
1918 Decl->setInvalidDecl();
1924 // Deduce the type for the iterator variable now rather than leaving it to
1925 // AddInitializerToDecl, so we can produce a more suitable diagnostic.
1927 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) ||
1928 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitType) ==
1930 SemaRef.Diag(Loc, DiagID) << Init->getType();
1931 if (InitType.isNull()) {
1932 Decl->setInvalidDecl();
1935 Decl->setType(InitType);
1937 // In ARC, infer lifetime.
1938 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
1939 // we're doing the equivalent of fast iteration.
1940 if (SemaRef.getLangOpts().ObjCAutoRefCount &&
1941 SemaRef.inferObjCARCLifetime(Decl))
1942 Decl->setInvalidDecl();
1944 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false);
1945 SemaRef.FinalizeDeclaration(Decl);
1946 SemaRef.CurContext->addHiddenDecl(Decl);
1951 // An enum to represent whether something is dealing with a call to begin()
1952 // or a call to end() in a range-based for loop.
1953 enum BeginEndFunction {
1958 /// Produce a note indicating which begin/end function was implicitly called
1959 /// by a C++11 for-range statement. This is often not obvious from the code,
1960 /// nor from the diagnostics produced when analysing the implicit expressions
1961 /// required in a for-range statement.
1962 void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
1963 BeginEndFunction BEF) {
1964 CallExpr *CE = dyn_cast<CallExpr>(E);
1967 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1970 SourceLocation Loc = D->getLocation();
1972 std::string Description;
1973 bool IsTemplate = false;
1974 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
1975 Description = SemaRef.getTemplateArgumentBindingsText(
1976 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
1980 SemaRef.Diag(Loc, diag::note_for_range_begin_end)
1981 << BEF << IsTemplate << Description << E->getType();
1984 /// Build a variable declaration for a for-range statement.
1985 VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
1986 QualType Type, const char *Name) {
1987 DeclContext *DC = SemaRef.CurContext;
1988 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
1989 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc);
1990 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type,
1992 Decl->setImplicit();
1998 static bool ObjCEnumerationCollection(Expr *Collection) {
1999 return !Collection->isTypeDependent()
2000 && Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2003 /// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
2005 /// C++11 [stmt.ranged]:
2006 /// A range-based for statement is equivalent to
2009 /// auto && __range = range-init;
2010 /// for ( auto __begin = begin-expr,
2011 /// __end = end-expr;
2012 /// __begin != __end;
2014 /// for-range-declaration = *__begin;
2019 /// The body of the loop is not available yet, since it cannot be analysed until
2020 /// we have determined the type of the for-range-declaration.
2021 StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
2022 SourceLocation CoawaitLoc, Stmt *First,
2023 SourceLocation ColonLoc, Expr *Range,
2024 SourceLocation RParenLoc,
2025 BuildForRangeKind Kind) {
2029 if (Range && ObjCEnumerationCollection(Range))
2030 return ActOnObjCForCollectionStmt(ForLoc, First, Range, RParenLoc);
2032 DeclStmt *DS = dyn_cast<DeclStmt>(First);
2033 assert(DS && "first part of for range not a decl stmt");
2035 if (!DS->isSingleDecl()) {
2036 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range);
2040 Decl *LoopVar = DS->getSingleDecl();
2041 if (LoopVar->isInvalidDecl() || !Range ||
2042 DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) {
2043 LoopVar->setInvalidDecl();
2047 // Build the coroutine state immediately and not later during template
2049 if (!CoawaitLoc.isInvalid()) {
2050 if (!ActOnCoroutineBodyStart(S, CoawaitLoc, "co_await"))
2054 // Build auto && __range = range-init
2055 SourceLocation RangeLoc = Range->getLocStart();
2056 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc,
2057 Context.getAutoRRefDeductType(),
2059 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
2060 diag::err_for_range_deduction_failure)) {
2061 LoopVar->setInvalidDecl();
2065 // Claim the type doesn't contain auto: we've already done the checking.
2066 DeclGroupPtrTy RangeGroup =
2067 BuildDeclaratorGroup(MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2068 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc);
2069 if (RangeDecl.isInvalid()) {
2070 LoopVar->setInvalidDecl();
2074 return BuildCXXForRangeStmt(ForLoc, CoawaitLoc, ColonLoc, RangeDecl.get(),
2075 /*BeginStmt=*/nullptr, /*EndStmt=*/nullptr,
2076 /*Cond=*/nullptr, /*Inc=*/nullptr,
2077 DS, RParenLoc, Kind);
2080 /// \brief Create the initialization, compare, and increment steps for
2081 /// the range-based for loop expression.
2082 /// This function does not handle array-based for loops,
2083 /// which are created in Sema::BuildCXXForRangeStmt.
2085 /// \returns a ForRangeStatus indicating success or what kind of error occurred.
2086 /// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2087 /// CandidateSet and BEF are set and some non-success value is returned on
2089 static Sema::ForRangeStatus
2090 BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2091 QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2092 SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2093 OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2094 ExprResult *EndExpr, BeginEndFunction *BEF) {
2095 DeclarationNameInfo BeginNameInfo(
2096 &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
2097 DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
2100 LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2101 Sema::LookupMemberName);
2102 LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2104 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2105 // - if _RangeT is a class type, the unqualified-ids begin and end are
2106 // looked up in the scope of class _RangeT as if by class member access
2107 // lookup (3.4.5), and if either (or both) finds at least one
2108 // declaration, begin-expr and end-expr are __range.begin() and
2109 // __range.end(), respectively;
2110 SemaRef.LookupQualifiedName(BeginMemberLookup, D);
2111 SemaRef.LookupQualifiedName(EndMemberLookup, D);
2113 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2114 SourceLocation RangeLoc = BeginVar->getLocation();
2115 *BEF = BeginMemberLookup.empty() ? BEF_end : BEF_begin;
2117 SemaRef.Diag(RangeLoc, diag::err_for_range_member_begin_end_mismatch)
2118 << RangeLoc << BeginRange->getType() << *BEF;
2119 return Sema::FRS_DiagnosticIssued;
2122 // - otherwise, begin-expr and end-expr are begin(__range) and
2123 // end(__range), respectively, where begin and end are looked up with
2124 // argument-dependent lookup (3.4.2). For the purposes of this name
2125 // lookup, namespace std is an associated namespace.
2130 Sema::ForRangeStatus RangeStatus =
2131 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
2132 BeginMemberLookup, CandidateSet,
2133 BeginRange, BeginExpr);
2135 if (RangeStatus != Sema::FRS_Success) {
2136 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2137 SemaRef.Diag(BeginRange->getLocStart(), diag::note_in_for_range)
2138 << ColonLoc << BEF_begin << BeginRange->getType();
2141 if (!CoawaitLoc.isInvalid()) {
2142 // FIXME: getCurScope() should not be used during template instantiation.
2143 // We should pick up the set of unqualified lookup results for operator
2144 // co_await during the initial parse.
2145 *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
2147 if (BeginExpr->isInvalid())
2148 return Sema::FRS_DiagnosticIssued;
2150 if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
2151 diag::err_for_range_iter_deduction_failure)) {
2152 NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
2153 return Sema::FRS_DiagnosticIssued;
2158 SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
2159 EndMemberLookup, CandidateSet,
2161 if (RangeStatus != Sema::FRS_Success) {
2162 if (RangeStatus == Sema::FRS_DiagnosticIssued)
2163 SemaRef.Diag(EndRange->getLocStart(), diag::note_in_for_range)
2164 << ColonLoc << BEF_end << EndRange->getType();
2167 if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2168 diag::err_for_range_iter_deduction_failure)) {
2169 NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
2170 return Sema::FRS_DiagnosticIssued;
2172 return Sema::FRS_Success;
2175 /// Speculatively attempt to dereference an invalid range expression.
2176 /// If the attempt fails, this function will return a valid, null StmtResult
2177 /// and emit no diagnostics.
2178 static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2179 SourceLocation ForLoc,
2180 SourceLocation CoawaitLoc,
2182 SourceLocation ColonLoc,
2184 SourceLocation RangeLoc,
2185 SourceLocation RParenLoc) {
2186 // Determine whether we can rebuild the for-range statement with a
2187 // dereferenced range expression.
2188 ExprResult AdjustedRange;
2190 Sema::SFINAETrap Trap(SemaRef);
2192 AdjustedRange = SemaRef.BuildUnaryOp(S, RangeLoc, UO_Deref, Range);
2193 if (AdjustedRange.isInvalid())
2194 return StmtResult();
2196 StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2197 S, ForLoc, CoawaitLoc, LoopVarDecl, ColonLoc, AdjustedRange.get(),
2198 RParenLoc, Sema::BFRK_Check);
2200 return StmtResult();
2203 // The attempt to dereference worked well enough that it could produce a valid
2204 // loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2205 // case there are any other (non-fatal) problems with it.
2206 SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
2207 << Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
2208 return SemaRef.ActOnCXXForRangeStmt(S, ForLoc, CoawaitLoc, LoopVarDecl,
2209 ColonLoc, AdjustedRange.get(), RParenLoc,
2210 Sema::BFRK_Rebuild);
2214 /// RAII object to automatically invalidate a declaration if an error occurs.
2215 struct InvalidateOnErrorScope {
2216 InvalidateOnErrorScope(Sema &SemaRef, Decl *D, bool Enabled)
2217 : Trap(SemaRef.Diags), D(D), Enabled(Enabled) {}
2218 ~InvalidateOnErrorScope() {
2219 if (Enabled && Trap.hasErrorOccurred())
2220 D->setInvalidDecl();
2223 DiagnosticErrorTrap Trap;
2229 /// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2231 Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
2232 SourceLocation ColonLoc, Stmt *RangeDecl,
2233 Stmt *Begin, Stmt *End, Expr *Cond,
2234 Expr *Inc, Stmt *LoopVarDecl,
2235 SourceLocation RParenLoc, BuildForRangeKind Kind) {
2236 // FIXME: This should not be used during template instantiation. We should
2237 // pick up the set of unqualified lookup results for the != and + operators
2238 // in the initial parse.
2240 // Testcase (accepts-invalid):
2241 // template<typename T> void f() { for (auto x : T()) {} }
2242 // namespace N { struct X { X begin(); X end(); int operator*(); }; }
2243 // bool operator!=(N::X, N::X); void operator++(N::X);
2244 // void g() { f<N::X>(); }
2245 Scope *S = getCurScope();
2247 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl);
2248 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl());
2249 QualType RangeVarType = RangeVar->getType();
2251 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl);
2252 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl());
2254 // If we hit any errors, mark the loop variable as invalid if its type
2256 InvalidateOnErrorScope Invalidate(*this, LoopVar,
2257 LoopVar->getType()->isUndeducedType());
2259 StmtResult BeginDeclStmt = Begin;
2260 StmtResult EndDeclStmt = End;
2261 ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2263 if (RangeVarType->isDependentType()) {
2264 // The range is implicitly used as a placeholder when it is dependent.
2265 RangeVar->markUsed(Context);
2267 // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2268 // them in properly when we instantiate the loop.
2269 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2270 if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
2271 for (auto *Binding : DD->bindings())
2272 Binding->setType(Context.DependentTy);
2273 LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
2275 } else if (!BeginDeclStmt.get()) {
2276 SourceLocation RangeLoc = RangeVar->getLocation();
2278 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2280 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2281 VK_LValue, ColonLoc);
2282 if (BeginRangeRef.isInvalid())
2285 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2286 VK_LValue, ColonLoc);
2287 if (EndRangeRef.isInvalid())
2290 QualType AutoType = Context.getAutoDeductType();
2291 Expr *Range = RangeVar->getInit();
2294 QualType RangeType = Range->getType();
2296 if (RequireCompleteType(RangeLoc, RangeType,
2297 diag::err_for_range_incomplete_type))
2300 // Build auto __begin = begin-expr, __end = end-expr.
2301 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2303 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType,
2306 // Build begin-expr and end-expr and attach to __begin and __end variables.
2307 ExprResult BeginExpr, EndExpr;
2308 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2309 // - if _RangeT is an array type, begin-expr and end-expr are __range and
2310 // __range + __bound, respectively, where __bound is the array bound. If
2311 // _RangeT is an array of unknown size or an array of incomplete type,
2312 // the program is ill-formed;
2314 // begin-expr is __range.
2315 BeginExpr = BeginRangeRef;
2316 if (!CoawaitLoc.isInvalid()) {
2317 BeginExpr = ActOnCoawaitExpr(S, ColonLoc, BeginExpr.get());
2318 if (BeginExpr.isInvalid())
2321 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2322 diag::err_for_range_iter_deduction_failure)) {
2323 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2327 // Find the array bound.
2328 ExprResult BoundExpr;
2329 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT))
2330 BoundExpr = IntegerLiteral::Create(
2331 Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc);
2332 else if (const VariableArrayType *VAT =
2333 dyn_cast<VariableArrayType>(UnqAT)) {
2334 // For a variably modified type we can't just use the expression within
2335 // the array bounds, since we don't want that to be re-evaluated here.
2336 // Rather, we need to determine what it was when the array was first
2337 // created - so we resort to using sizeof(vla)/sizeof(element).
2341 // b = -1; <-- This should not affect the num of iterations below
2342 // for (int &c : vla) { .. }
2345 // FIXME: This results in codegen generating IR that recalculates the
2346 // run-time number of elements (as opposed to just using the IR Value
2347 // that corresponds to the run-time value of each bound that was
2348 // generated when the array was created.) If this proves too embarassing
2349 // even for unoptimized IR, consider passing a magic-value/cookie to
2350 // codegen that then knows to simply use that initial llvm::Value (that
2351 // corresponds to the bound at time of array creation) within
2352 // getelementptr. But be prepared to pay the price of increasing a
2353 // customized form of coupling between the two components - which could
2354 // be hard to maintain as the codebase evolves.
2356 ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2357 EndVar->getLocation(), UETT_SizeOf,
2359 CreateParsedType(VAT->desugar(), Context.getTrivialTypeSourceInfo(
2360 VAT->desugar(), RangeLoc))
2362 EndVar->getSourceRange());
2363 if (SizeOfVLAExprR.isInvalid())
2366 ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2367 EndVar->getLocation(), UETT_SizeOf,
2369 CreateParsedType(VAT->desugar(),
2370 Context.getTrivialTypeSourceInfo(
2371 VAT->getElementType(), RangeLoc))
2373 EndVar->getSourceRange());
2374 if (SizeOfEachElementExprR.isInvalid())
2378 ActOnBinOp(S, EndVar->getLocation(), tok::slash,
2379 SizeOfVLAExprR.get(), SizeOfEachElementExprR.get());
2380 if (BoundExpr.isInvalid())
2384 // Can't be a DependentSizedArrayType or an IncompleteArrayType since
2385 // UnqAT is not incomplete and Range is not type-dependent.
2386 llvm_unreachable("Unexpected array type in for-range");
2389 // end-expr is __range + __bound.
2390 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(),
2392 if (EndExpr.isInvalid())
2394 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
2395 diag::err_for_range_iter_deduction_failure)) {
2396 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2400 OverloadCandidateSet CandidateSet(RangeLoc,
2401 OverloadCandidateSet::CSK_Normal);
2402 BeginEndFunction BEFFailure;
2403 ForRangeStatus RangeStatus = BuildNonArrayForRange(
2404 *this, BeginRangeRef.get(), EndRangeRef.get(), RangeType, BeginVar,
2405 EndVar, ColonLoc, CoawaitLoc, &CandidateSet, &BeginExpr, &EndExpr,
2408 if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2409 BEFFailure == BEF_begin) {
2410 // If the range is being built from an array parameter, emit a
2411 // a diagnostic that it is being treated as a pointer.
2412 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Range)) {
2413 if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
2414 QualType ArrayTy = PVD->getOriginalType();
2415 QualType PointerTy = PVD->getType();
2416 if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2417 Diag(Range->getLocStart(), diag::err_range_on_array_parameter)
2418 << RangeLoc << PVD << ArrayTy << PointerTy;
2419 Diag(PVD->getLocation(), diag::note_declared_at);
2425 // If building the range failed, try dereferencing the range expression
2426 // unless a diagnostic was issued or the end function is problematic.
2427 StmtResult SR = RebuildForRangeWithDereference(*this, S, ForLoc,
2429 LoopVarDecl, ColonLoc,
2432 if (SR.isInvalid() || SR.isUsable())
2436 // Otherwise, emit diagnostics if we haven't already.
2437 if (RangeStatus == FRS_NoViableFunction) {
2438 Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2439 Diag(Range->getLocStart(), diag::err_for_range_invalid)
2440 << RangeLoc << Range->getType() << BEFFailure;
2441 CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Range);
2443 // Return an error if no fix was discovered.
2444 if (RangeStatus != FRS_Success)
2448 assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
2449 "invalid range expression in for loop");
2451 // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2452 // C++1z removes this restriction.
2453 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2454 if (!Context.hasSameType(BeginType, EndType)) {
2455 Diag(RangeLoc, getLangOpts().CPlusPlus1z
2456 ? diag::warn_for_range_begin_end_types_differ
2457 : diag::ext_for_range_begin_end_types_differ)
2458 << BeginType << EndType;
2459 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2460 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2464 ActOnDeclStmt(ConvertDeclToDeclGroup(BeginVar), ColonLoc, ColonLoc);
2466 ActOnDeclStmt(ConvertDeclToDeclGroup(EndVar), ColonLoc, ColonLoc);
2468 const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2469 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2470 VK_LValue, ColonLoc);
2471 if (BeginRef.isInvalid())
2474 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
2475 VK_LValue, ColonLoc);
2476 if (EndRef.isInvalid())
2479 // Build and check __begin != __end expression.
2480 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
2481 BeginRef.get(), EndRef.get());
2482 if (!NotEqExpr.isInvalid())
2483 NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
2484 if (!NotEqExpr.isInvalid())
2485 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
2486 if (NotEqExpr.isInvalid()) {
2487 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2488 << RangeLoc << 0 << BeginRangeRef.get()->getType();
2489 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2490 if (!Context.hasSameType(BeginType, EndType))
2491 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
2495 // Build and check ++__begin expression.
2496 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2497 VK_LValue, ColonLoc);
2498 if (BeginRef.isInvalid())
2501 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
2502 if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
2503 // FIXME: getCurScope() should not be used during template instantiation.
2504 // We should pick up the set of unqualified lookup results for operator
2505 // co_await during the initial parse.
2506 IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
2507 if (!IncrExpr.isInvalid())
2508 IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
2509 if (IncrExpr.isInvalid()) {
2510 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2511 << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
2512 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2516 // Build and check *__begin expression.
2517 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2518 VK_LValue, ColonLoc);
2519 if (BeginRef.isInvalid())
2522 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get());
2523 if (DerefExpr.isInvalid()) {
2524 Diag(RangeLoc, diag::note_for_range_invalid_iterator)
2525 << RangeLoc << 1 << BeginRangeRef.get()->getType();
2526 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2530 // Attach *__begin as initializer for VD. Don't touch it if we're just
2531 // trying to determine whether this would be a valid range.
2532 if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2533 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false);
2534 if (LoopVar->isInvalidDecl())
2535 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
2539 // Don't bother to actually allocate the result if we're just trying to
2540 // determine whether it would be valid.
2541 if (Kind == BFRK_Check)
2542 return StmtResult();
2544 return new (Context) CXXForRangeStmt(
2545 RangeDS, cast_or_null<DeclStmt>(BeginDeclStmt.get()),
2546 cast_or_null<DeclStmt>(EndDeclStmt.get()), NotEqExpr.get(),
2547 IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
2548 ColonLoc, RParenLoc);
2551 /// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
2553 StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
2556 ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(S);
2558 ForStmt->setBody(B);
2562 // Warn when the loop variable is a const reference that creates a copy.
2563 // Suggest using the non-reference type for copies. If a copy can be prevented
2564 // suggest the const reference type that would do so.
2565 // For instance, given "for (const &Foo : Range)", suggest
2566 // "for (const Foo : Range)" to denote a copy is made for the loop. If
2567 // possible, also suggest "for (const &Bar : Range)" if this type prevents
2568 // the copy altogether.
2569 static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
2571 QualType RangeInitType) {
2572 const Expr *InitExpr = VD->getInit();
2576 QualType VariableType = VD->getType();
2578 if (auto Cleanups = dyn_cast<ExprWithCleanups>(InitExpr))
2579 if (!Cleanups->cleanupsHaveSideEffects())
2580 InitExpr = Cleanups->getSubExpr();
2582 const MaterializeTemporaryExpr *MTE =
2583 dyn_cast<MaterializeTemporaryExpr>(InitExpr);
2589 const Expr *E = MTE->GetTemporaryExpr()->IgnoreImpCasts();
2591 // Searching for either UnaryOperator for dereference of a pointer or
2592 // CXXOperatorCallExpr for handling iterators.
2593 while (!isa<CXXOperatorCallExpr>(E) && !isa<UnaryOperator>(E)) {
2594 if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(E)) {
2596 } else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(E)) {
2597 const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
2600 const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
2601 E = MTE->GetTemporaryExpr();
2603 E = E->IgnoreImpCasts();
2606 bool ReturnsReference = false;
2607 if (isa<UnaryOperator>(E)) {
2608 ReturnsReference = true;
2610 const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(E);
2611 const FunctionDecl *FD = Call->getDirectCallee();
2612 QualType ReturnType = FD->getReturnType();
2613 ReturnsReference = ReturnType->isReferenceType();
2616 if (ReturnsReference) {
2617 // Loop variable creates a temporary. Suggest either to go with
2618 // non-reference loop variable to indiciate a copy is made, or
2619 // the correct time to bind a const reference.
2620 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_const_reference_copy)
2621 << VD << VariableType << E->getType();
2622 QualType NonReferenceType = VariableType.getNonReferenceType();
2623 NonReferenceType.removeLocalConst();
2624 QualType NewReferenceType =
2625 SemaRef.Context.getLValueReferenceType(E->getType().withConst());
2626 SemaRef.Diag(VD->getLocStart(), diag::note_use_type_or_non_reference)
2627 << NonReferenceType << NewReferenceType << VD->getSourceRange();
2629 // The range always returns a copy, so a temporary is always created.
2630 // Suggest removing the reference from the loop variable.
2631 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_variable_always_copy)
2632 << VD << RangeInitType;
2633 QualType NonReferenceType = VariableType.getNonReferenceType();
2634 NonReferenceType.removeLocalConst();
2635 SemaRef.Diag(VD->getLocStart(), diag::note_use_non_reference_type)
2636 << NonReferenceType << VD->getSourceRange();
2640 // Warns when the loop variable can be changed to a reference type to
2641 // prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
2642 // "for (const Foo &x : Range)" if this form does not make a copy.
2643 static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
2644 const VarDecl *VD) {
2645 const Expr *InitExpr = VD->getInit();
2649 QualType VariableType = VD->getType();
2651 if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(InitExpr)) {
2652 if (!CE->getConstructor()->isCopyConstructor())
2654 } else if (const CastExpr *CE = dyn_cast<CastExpr>(InitExpr)) {
2655 if (CE->getCastKind() != CK_LValueToRValue)
2661 // TODO: Determine a maximum size that a POD type can be before a diagnostic
2662 // should be emitted. Also, only ignore POD types with trivial copy
2664 if (VariableType.isPODType(SemaRef.Context))
2667 // Suggest changing from a const variable to a const reference variable
2668 // if doing so will prevent a copy.
2669 SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
2670 << VD << VariableType << InitExpr->getType();
2671 SemaRef.Diag(VD->getLocStart(), diag::note_use_reference_type)
2672 << SemaRef.Context.getLValueReferenceType(VariableType)
2673 << VD->getSourceRange();
2676 /// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
2677 /// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
2678 /// using "const foo x" to show that a copy is made
2679 /// 2) for (const bar &x : foos) where bar is a temporary intialized by bar.
2680 /// Suggest either "const bar x" to keep the copying or "const foo& x" to
2681 /// prevent the copy.
2682 /// 3) for (const foo x : foos) where x is constructed from a reference foo.
2683 /// Suggest "const foo &x" to prevent the copy.
2684 static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
2685 const CXXForRangeStmt *ForStmt) {
2686 if (SemaRef.Diags.isIgnored(diag::warn_for_range_const_reference_copy,
2687 ForStmt->getLocStart()) &&
2688 SemaRef.Diags.isIgnored(diag::warn_for_range_variable_always_copy,
2689 ForStmt->getLocStart()) &&
2690 SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
2691 ForStmt->getLocStart())) {
2695 const VarDecl *VD = ForStmt->getLoopVariable();
2699 QualType VariableType = VD->getType();
2701 if (VariableType->isIncompleteType())
2704 const Expr *InitExpr = VD->getInit();
2708 if (VariableType->isReferenceType()) {
2709 DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
2710 ForStmt->getRangeInit()->getType());
2711 } else if (VariableType.isConstQualified()) {
2712 DiagnoseForRangeConstVariableCopies(SemaRef, VD);
2716 /// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
2717 /// This is a separate step from ActOnCXXForRangeStmt because analysis of the
2718 /// body cannot be performed until after the type of the range variable is
2720 StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
2724 if (isa<ObjCForCollectionStmt>(S))
2725 return FinishObjCForCollectionStmt(S, B);
2727 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S);
2728 ForStmt->setBody(B);
2730 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
2731 diag::warn_empty_range_based_for_body);
2733 DiagnoseForRangeVariableCopies(*this, ForStmt);
2738 StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
2739 SourceLocation LabelLoc,
2740 LabelDecl *TheDecl) {
2741 getCurFunction()->setHasBranchIntoScope();
2742 TheDecl->markUsed(Context);
2743 return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
2747 Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
2749 // Convert operand to void*
2750 if (!E->isTypeDependent()) {
2751 QualType ETy = E->getType();
2752 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
2753 ExprResult ExprRes = E;
2754 AssignConvertType ConvTy =
2755 CheckSingleAssignmentConstraints(DestTy, ExprRes);
2756 if (ExprRes.isInvalid())
2759 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
2763 ExprResult ExprRes = ActOnFinishFullExpr(E);
2764 if (ExprRes.isInvalid())
2768 getCurFunction()->setHasIndirectGoto();
2770 return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
2773 static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
2774 const Scope &DestScope) {
2775 if (!S.CurrentSEHFinally.empty() &&
2776 DestScope.Contains(*S.CurrentSEHFinally.back())) {
2777 S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
2782 Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
2783 Scope *S = CurScope->getContinueParent();
2785 // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
2786 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
2788 CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);
2790 return new (Context) ContinueStmt(ContinueLoc);
2794 Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
2795 Scope *S = CurScope->getBreakParent();
2797 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
2798 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
2800 if (S->isOpenMPLoopScope())
2801 return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
2803 CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);
2805 return new (Context) BreakStmt(BreakLoc);
2808 /// \brief Determine whether the given expression is a candidate for
2809 /// copy elision in either a return statement or a throw expression.
2811 /// \param ReturnType If we're determining the copy elision candidate for
2812 /// a return statement, this is the return type of the function. If we're
2813 /// determining the copy elision candidate for a throw expression, this will
2816 /// \param E The expression being returned from the function or block, or
2819 /// \param AllowParamOrMoveConstructible Whether we allow function parameters or
2820 /// id-expressions that could be moved out of the function to be considered NRVO
2821 /// candidates. C++ prohibits these for NRVO itself, but we re-use this logic to
2822 /// determine whether we should try to move as part of a return or throw (which
2823 /// does allow function parameters).
2825 /// \returns The NRVO candidate variable, if the return statement may use the
2826 /// NRVO, or NULL if there is no such candidate.
2827 VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, Expr *E,
2828 bool AllowParamOrMoveConstructible) {
2829 if (!getLangOpts().CPlusPlus)
2832 // - in a return statement in a function [where] ...
2833 // ... the expression is the name of a non-volatile automatic object ...
2834 DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens());
2835 if (!DR || DR->refersToEnclosingVariableOrCapture())
2837 VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
2841 if (isCopyElisionCandidate(ReturnType, VD, AllowParamOrMoveConstructible))
2846 bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
2847 bool AllowParamOrMoveConstructible) {
2848 QualType VDType = VD->getType();
2849 // - in a return statement in a function with ...
2850 // ... a class return type ...
2851 if (!ReturnType.isNull() && !ReturnType->isDependentType()) {
2852 if (!ReturnType->isRecordType())
2854 // ... the same cv-unqualified type as the function return type ...
2855 // When considering moving this expression out, allow dissimilar types.
2856 if (!AllowParamOrMoveConstructible && !VDType->isDependentType() &&
2857 !Context.hasSameUnqualifiedType(ReturnType, VDType))
2861 // ...object (other than a function or catch-clause parameter)...
2862 if (VD->getKind() != Decl::Var &&
2863 !(AllowParamOrMoveConstructible && VD->getKind() == Decl::ParmVar))
2865 if (VD->isExceptionVariable()) return false;
2868 if (!VD->hasLocalStorage()) return false;
2870 // Return false if VD is a __block variable. We don't want to implicitly move
2871 // out of a __block variable during a return because we cannot assume the
2872 // variable will no longer be used.
2873 if (VD->hasAttr<BlocksAttr>()) return false;
2875 if (AllowParamOrMoveConstructible)
2878 // ...non-volatile...
2879 if (VD->getType().isVolatileQualified()) return false;
2881 // Variables with higher required alignment than their type's ABI
2882 // alignment cannot use NRVO.
2883 if (!VD->getType()->isDependentType() && VD->hasAttr<AlignedAttr>() &&
2884 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType()))
2890 /// \brief Perform the initialization of a potentially-movable value, which
2891 /// is the result of return value.
2893 /// This routine implements C++14 [class.copy]p32, which attempts to treat
2894 /// returned lvalues as rvalues in certain cases (to prefer move construction),
2895 /// then falls back to treating them as lvalues if that failed.
2897 Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
2898 const VarDecl *NRVOCandidate,
2899 QualType ResultType,
2902 // C++14 [class.copy]p32:
2903 // When the criteria for elision of a copy/move operation are met, but not for
2904 // an exception-declaration, and the object to be copied is designated by an
2905 // lvalue, or when the expression in a return statement is a (possibly
2906 // parenthesized) id-expression that names an object with automatic storage
2907 // duration declared in the body or parameter-declaration-clause of the
2908 // innermost enclosing function or lambda-expression, overload resolution to
2909 // select the constructor for the copy is first performed as if the object
2910 // were designated by an rvalue.
2911 ExprResult Res = ExprError();
2913 if (AllowNRVO && !NRVOCandidate)
2914 NRVOCandidate = getCopyElisionCandidate(ResultType, Value, true);
2916 if (AllowNRVO && NRVOCandidate) {
2917 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
2918 CK_NoOp, Value, VK_XValue);
2920 Expr *InitExpr = &AsRvalue;
2922 InitializationKind Kind = InitializationKind::CreateCopy(
2923 Value->getLocStart(), Value->getLocStart());
2925 InitializationSequence Seq(*this, Entity, Kind, InitExpr);
2927 for (const InitializationSequence::Step &Step : Seq.steps()) {
2929 InitializationSequence::SK_ConstructorInitialization ||
2930 (Step.Kind == InitializationSequence::SK_UserConversion &&
2931 isa<CXXConstructorDecl>(Step.Function.Function))))
2934 CXXConstructorDecl *Constructor =
2935 cast<CXXConstructorDecl>(Step.Function.Function);
2937 const RValueReferenceType *RRefType
2938 = Constructor->getParamDecl(0)->getType()
2939 ->getAs<RValueReferenceType>();
2941 // [...] If the first overload resolution fails or was not performed, or
2942 // if the type of the first parameter of the selected constructor is not
2943 // an rvalue reference to the object's type (possibly cv-qualified),
2944 // overload resolution is performed again, considering the object as an
2947 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
2948 NRVOCandidate->getType()))
2951 // Promote "AsRvalue" to the heap, since we now need this
2952 // expression node to persist.
2953 Value = ImplicitCastExpr::Create(Context, Value->getType(), CK_NoOp,
2954 Value, nullptr, VK_XValue);
2956 // Complete type-checking the initialization of the return type
2957 // using the constructor we found.
2958 Res = Seq.Perform(*this, Entity, Kind, Value);
2963 // Either we didn't meet the criteria for treating an lvalue as an rvalue,
2964 // above, or overload resolution failed. Either way, we need to try
2965 // (again) now with the return value expression as written.
2966 if (Res.isInvalid())
2967 Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
2972 /// \brief Determine whether the declared return type of the specified function
2973 /// contains 'auto'.
2974 static bool hasDeducedReturnType(FunctionDecl *FD) {
2975 const FunctionProtoType *FPT =
2976 FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
2977 return FPT->getReturnType()->isUndeducedType();
2980 /// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
2981 /// for capturing scopes.
2984 Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
2985 // If this is the first return we've seen, infer the return type.
2986 // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
2987 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
2988 QualType FnRetType = CurCap->ReturnType;
2989 LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
2990 bool HasDeducedReturnType =
2991 CurLambda && hasDeducedReturnType(CurLambda->CallOperator);
2993 if (ExprEvalContexts.back().Context ==
2994 ExpressionEvaluationContext::DiscardedStatement &&
2995 (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
2997 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3000 RetValExp = ER.get();
3002 return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3005 if (HasDeducedReturnType) {
3006 // In C++1y, the return type may involve 'auto'.
3007 // FIXME: Blocks might have a return type of 'auto' explicitly specified.
3008 FunctionDecl *FD = CurLambda->CallOperator;
3009 if (CurCap->ReturnType.isNull())
3010 CurCap->ReturnType = FD->getReturnType();
3012 AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3013 assert(AT && "lost auto type from lambda return type");
3014 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3015 FD->setInvalidDecl();
3018 CurCap->ReturnType = FnRetType = FD->getReturnType();
3019 } else if (CurCap->HasImplicitReturnType) {
3020 // For blocks/lambdas with implicit return types, we check each return
3021 // statement individually, and deduce the common return type when the block
3022 // or lambda is completed.
3023 // FIXME: Fold this into the 'auto' codepath above.
3024 if (RetValExp && !isa<InitListExpr>(RetValExp)) {
3025 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
3026 if (Result.isInvalid())
3028 RetValExp = Result.get();
3030 // DR1048: even prior to C++14, we should use the 'auto' deduction rules
3031 // when deducing a return type for a lambda-expression (or by extension
3032 // for a block). These rules differ from the stated C++11 rules only in
3033 // that they remove top-level cv-qualifiers.
3034 if (!CurContext->isDependentContext())
3035 FnRetType = RetValExp->getType().getUnqualifiedType();
3037 FnRetType = CurCap->ReturnType = Context.DependentTy;
3040 // C++11 [expr.lambda.prim]p4 bans inferring the result from an
3041 // initializer list, because it is not an expression (even
3042 // though we represent it as one). We still deduce 'void'.
3043 Diag(ReturnLoc, diag::err_lambda_return_init_list)
3044 << RetValExp->getSourceRange();
3047 FnRetType = Context.VoidTy;
3050 // Although we'll properly infer the type of the block once it's completed,
3051 // make sure we provide a return type now for better error recovery.
3052 if (CurCap->ReturnType.isNull())
3053 CurCap->ReturnType = FnRetType;
3055 assert(!FnRetType.isNull());
3057 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
3058 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) {
3059 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
3062 } else if (CapturedRegionScopeInfo *CurRegion =
3063 dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
3064 Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3067 assert(CurLambda && "unknown kind of captured scope");
3068 if (CurLambda->CallOperator->getType()->getAs<FunctionType>()
3069 ->getNoReturnAttr()) {
3070 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
3075 // Otherwise, verify that this result type matches the previous one. We are
3076 // pickier with blocks than for normal functions because we don't have GCC
3077 // compatibility to worry about here.
3078 const VarDecl *NRVOCandidate = nullptr;
3079 if (FnRetType->isDependentType()) {
3080 // Delay processing for now. TODO: there are lots of dependent
3081 // types we can conclusively prove aren't void.
3082 } else if (FnRetType->isVoidType()) {
3083 if (RetValExp && !isa<InitListExpr>(RetValExp) &&
3084 !(getLangOpts().CPlusPlus &&
3085 (RetValExp->isTypeDependent() ||
3086 RetValExp->getType()->isVoidType()))) {
3087 if (!getLangOpts().CPlusPlus &&
3088 RetValExp->getType()->isVoidType())
3089 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
3091 Diag(ReturnLoc, diag::err_return_block_has_expr);
3092 RetValExp = nullptr;
3095 } else if (!RetValExp) {
3096 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
3097 } else if (!RetValExp->isTypeDependent()) {
3098 // we have a non-void block with an expression, continue checking
3100 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3101 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3104 // In C++ the return statement is handled via a copy initialization.
3105 // the C version of which boils down to CheckSingleAssignmentConstraints.
3106 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3107 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
3109 NRVOCandidate != nullptr);
3110 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
3111 FnRetType, RetValExp);
3112 if (Res.isInvalid()) {
3113 // FIXME: Cleanup temporaries here, anyway?
3116 RetValExp = Res.get();
3117 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc);
3119 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3123 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3126 RetValExp = ER.get();
3128 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp,
3131 // If we need to check for the named return value optimization,
3132 // or if we need to infer the return type,
3133 // save the return statement in our scope for later processing.
3134 if (CurCap->HasImplicitReturnType || NRVOCandidate)
3135 FunctionScopes.back()->Returns.push_back(Result);
3137 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3138 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3144 /// \brief Marks all typedefs in all local classes in a type referenced.
3146 /// In a function like
3148 /// struct S { typedef int a; };
3152 /// the local type escapes and could be referenced in some TUs but not in
3153 /// others. Pretend that all local typedefs are always referenced, to not warn
3154 /// on this. This isn't necessary if f has internal linkage, or the typedef
3156 class LocalTypedefNameReferencer
3157 : public RecursiveASTVisitor<LocalTypedefNameReferencer> {
3159 LocalTypedefNameReferencer(Sema &S) : S(S) {}
3160 bool VisitRecordType(const RecordType *RT);
3164 bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
3165 auto *R = dyn_cast<CXXRecordDecl>(RT->getDecl());
3166 if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3167 R->isDependentType())
3169 for (auto *TmpD : R->decls())
3170 if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
3171 if (T->getAccess() != AS_private || R->hasFriends())
3172 S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
3177 TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3178 TypeLoc TL = FD->getTypeSourceInfo()->getTypeLoc().IgnoreParens();
3179 while (auto ATL = TL.getAs<AttributedTypeLoc>())
3180 TL = ATL.getModifiedLoc().IgnoreParens();
3181 return TL.castAs<FunctionProtoTypeLoc>().getReturnLoc();
3184 /// Deduce the return type for a function from a returned expression, per
3185 /// C++1y [dcl.spec.auto]p6.
3186 bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3187 SourceLocation ReturnLoc,
3190 TypeLoc OrigResultType = getReturnTypeLoc(FD);
3193 if (RetExpr && isa<InitListExpr>(RetExpr)) {
3194 // If the deduction is for a return statement and the initializer is
3195 // a braced-init-list, the program is ill-formed.
3196 Diag(RetExpr->getExprLoc(),
3197 getCurLambda() ? diag::err_lambda_return_init_list
3198 : diag::err_auto_fn_return_init_list)
3199 << RetExpr->getSourceRange();
3203 if (FD->isDependentContext()) {
3204 // C++1y [dcl.spec.auto]p12:
3205 // Return type deduction [...] occurs when the definition is
3206 // instantiated even if the function body contains a return
3207 // statement with a non-type-dependent operand.
3208 assert(AT->isDeduced() && "should have deduced to dependent type");
3213 // Otherwise, [...] deduce a value for U using the rules of template
3214 // argument deduction.
3215 DeduceAutoResult DAR = DeduceAutoType(OrigResultType, RetExpr, Deduced);
3217 if (DAR == DAR_Failed && !FD->isInvalidDecl())
3218 Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
3219 << OrigResultType.getType() << RetExpr->getType();
3221 if (DAR != DAR_Succeeded)
3224 // If a local type is part of the returned type, mark its fields as
3226 LocalTypedefNameReferencer Referencer(*this);
3227 Referencer.TraverseType(RetExpr->getType());
3229 // In the case of a return with no operand, the initializer is considered
3232 // Deduction here can only succeed if the return type is exactly 'cv auto'
3233 // or 'decltype(auto)', so just check for that case directly.
3234 if (!OrigResultType.getType()->getAs<AutoType>()) {
3235 Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
3236 << OrigResultType.getType();
3239 // We always deduce U = void in this case.
3240 Deduced = SubstAutoType(OrigResultType.getType(), Context.VoidTy);
3241 if (Deduced.isNull())
3245 // If a function with a declared return type that contains a placeholder type
3246 // has multiple return statements, the return type is deduced for each return
3247 // statement. [...] if the type deduced is not the same in each deduction,
3248 // the program is ill-formed.
3249 QualType DeducedT = AT->getDeducedType();
3250 if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
3251 AutoType *NewAT = Deduced->getContainedAutoType();
3252 // It is possible that NewAT->getDeducedType() is null. When that happens,
3253 // we should not crash, instead we ignore this deduction.
3254 if (NewAT->getDeducedType().isNull())
3257 CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
3259 CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(
3260 NewAT->getDeducedType());
3261 if (!FD->isDependentContext() && OldDeducedType != NewDeducedType) {
3262 const LambdaScopeInfo *LambdaSI = getCurLambda();
3263 if (LambdaSI && LambdaSI->HasImplicitReturnType) {
3264 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3265 << NewAT->getDeducedType() << DeducedT
3266 << true /*IsLambda*/;
3268 Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3269 << (AT->isDecltypeAuto() ? 1 : 0)
3270 << NewAT->getDeducedType() << DeducedT;
3274 } else if (!FD->isInvalidDecl()) {
3275 // Update all declarations of the function to have the deduced return type.
3276 Context.adjustDeducedFunctionResultType(FD, Deduced);
3283 Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3285 StmtResult R = BuildReturnStmt(ReturnLoc, RetValExp);
3286 if (R.isInvalid() || ExprEvalContexts.back().Context ==
3287 ExpressionEvaluationContext::DiscardedStatement)
3291 const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
3292 CurScope->addNRVOCandidate(VD);
3294 CurScope->setNoNRVO();
3297 CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
3302 StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
3303 // Check for unexpanded parameter packs.
3304 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
3307 if (isa<CapturingScopeInfo>(getCurFunction()))
3308 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
3311 QualType RelatedRetType;
3312 const AttrVec *Attrs = nullptr;
3313 bool isObjCMethod = false;
3315 if (const FunctionDecl *FD = getCurFunctionDecl()) {
3316 FnRetType = FD->getReturnType();
3318 Attrs = &FD->getAttrs();
3319 if (FD->isNoReturn())
3320 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
3321 << FD->getDeclName();
3322 if (FD->isMain() && RetValExp)
3323 if (isa<CXXBoolLiteralExpr>(RetValExp))
3324 Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
3325 << RetValExp->getSourceRange();
3326 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3327 FnRetType = MD->getReturnType();
3328 isObjCMethod = true;
3330 Attrs = &MD->getAttrs();
3331 if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3332 // In the implementation of a method with a related return type, the
3333 // type used to type-check the validity of return statements within the
3334 // method body is a pointer to the type of the class being implemented.
3335 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface());
3336 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType);
3338 } else // If we don't have a function/method context, bail.
3341 // C++1z: discarded return statements are not considered when deducing a
3343 if (ExprEvalContexts.back().Context ==
3344 ExpressionEvaluationContext::DiscardedStatement &&
3345 FnRetType->getContainedAutoType()) {
3347 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3350 RetValExp = ER.get();
3352 return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3355 // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3357 if (getLangOpts().CPlusPlus14) {
3358 if (AutoType *AT = FnRetType->getContainedAutoType()) {
3359 FunctionDecl *FD = cast<FunctionDecl>(CurContext);
3360 if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
3361 FD->setInvalidDecl();
3364 FnRetType = FD->getReturnType();
3369 bool HasDependentReturnType = FnRetType->isDependentType();
3371 ReturnStmt *Result = nullptr;
3372 if (FnRetType->isVoidType()) {
3374 if (isa<InitListExpr>(RetValExp)) {
3375 // We simply never allow init lists as the return value of void
3376 // functions. This is compatible because this was never allowed before,
3377 // so there's no legacy code to deal with.
3378 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3379 int FunctionKind = 0;
3380 if (isa<ObjCMethodDecl>(CurDecl))
3382 else if (isa<CXXConstructorDecl>(CurDecl))
3384 else if (isa<CXXDestructorDecl>(CurDecl))
3387 Diag(ReturnLoc, diag::err_return_init_list)
3388 << CurDecl->getDeclName() << FunctionKind
3389 << RetValExp->getSourceRange();
3391 // Drop the expression.
3392 RetValExp = nullptr;
3393 } else if (!RetValExp->isTypeDependent()) {
3394 // C99 6.8.6.4p1 (ext_ since GCC warns)
3395 unsigned D = diag::ext_return_has_expr;
3396 if (RetValExp->getType()->isVoidType()) {
3397 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3398 if (isa<CXXConstructorDecl>(CurDecl) ||
3399 isa<CXXDestructorDecl>(CurDecl))
3400 D = diag::err_ctor_dtor_returns_void;
3402 D = diag::ext_return_has_void_expr;
3405 ExprResult Result = RetValExp;
3406 Result = IgnoredValueConversions(Result.get());
3407 if (Result.isInvalid())
3409 RetValExp = Result.get();
3410 RetValExp = ImpCastExprToType(RetValExp,
3411 Context.VoidTy, CK_ToVoid).get();
3413 // return of void in constructor/destructor is illegal in C++.
3414 if (D == diag::err_ctor_dtor_returns_void) {
3415 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3417 << CurDecl->getDeclName() << isa<CXXDestructorDecl>(CurDecl)
3418 << RetValExp->getSourceRange();
3420 // return (some void expression); is legal in C++.
3421 else if (D != diag::ext_return_has_void_expr ||
3422 !getLangOpts().CPlusPlus) {
3423 NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
3425 int FunctionKind = 0;
3426 if (isa<ObjCMethodDecl>(CurDecl))
3428 else if (isa<CXXConstructorDecl>(CurDecl))
3430 else if (isa<CXXDestructorDecl>(CurDecl))
3434 << CurDecl->getDeclName() << FunctionKind
3435 << RetValExp->getSourceRange();
3440 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3443 RetValExp = ER.get();
3447 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
3448 } else if (!RetValExp && !HasDependentReturnType) {
3449 FunctionDecl *FD = getCurFunctionDecl();
3452 if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
3453 // C++11 [stmt.return]p2
3454 DiagID = diag::err_constexpr_return_missing_expr;
3455 FD->setInvalidDecl();
3456 } else if (getLangOpts().C99) {
3457 // C99 6.8.6.4p1 (ext_ since GCC warns)
3458 DiagID = diag::ext_return_missing_expr;
3461 DiagID = diag::warn_return_missing_expr;
3465 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
3467 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
3469 Result = new (Context) ReturnStmt(ReturnLoc);
3471 assert(RetValExp || HasDependentReturnType);
3472 const VarDecl *NRVOCandidate = nullptr;
3474 QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
3476 // C99 6.8.6.4p3(136): The return statement is not an assignment. The
3477 // overlap restriction of subclause 6.5.16.1 does not apply to the case of
3480 // In C++ the return statement is handled via a copy initialization,
3481 // the C version of which boils down to CheckSingleAssignmentConstraints.
3483 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false);
3484 if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
3485 // we have a non-void function with an expression, continue checking
3486 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc,
3488 NRVOCandidate != nullptr);
3489 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate,
3490 RetType, RetValExp);
3491 if (Res.isInvalid()) {
3492 // FIXME: Clean up temporaries here anyway?
3495 RetValExp = Res.getAs<Expr>();
3497 // If we have a related result type, we need to implicitly
3498 // convert back to the formal result type. We can't pretend to
3499 // initialize the result again --- we might end double-retaining
3500 // --- so instead we initialize a notional temporary.
3501 if (!RelatedRetType.isNull()) {
3502 Entity = InitializedEntity::InitializeRelatedResult(getCurMethodDecl(),
3504 Res = PerformCopyInitialization(Entity, ReturnLoc, RetValExp);
3505 if (Res.isInvalid()) {
3506 // FIXME: Clean up temporaries here anyway?
3509 RetValExp = Res.getAs<Expr>();
3512 CheckReturnValExpr(RetValExp, FnRetType, ReturnLoc, isObjCMethod, Attrs,
3513 getCurFunctionDecl());
3517 ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
3520 RetValExp = ER.get();
3522 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
3525 // If we need to check for the named return value optimization, save the
3526 // return statement in our scope for later processing.
3527 if (Result->getNRVOCandidate())
3528 FunctionScopes.back()->Returns.push_back(Result);
3530 if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3531 FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3537 Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
3538 SourceLocation RParen, Decl *Parm,
3540 VarDecl *Var = cast_or_null<VarDecl>(Parm);
3541 if (Var && Var->isInvalidDecl())
3544 return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
3548 Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
3549 return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
3553 Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
3554 MultiStmtArg CatchStmts, Stmt *Finally) {
3555 if (!getLangOpts().ObjCExceptions)
3556 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
3558 getCurFunction()->setHasBranchProtectedScope();
3559 unsigned NumCatchStmts = CatchStmts.size();
3560 return ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.data(),
3561 NumCatchStmts, Finally);
3564 StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
3566 ExprResult Result = DefaultLvalueConversion(Throw);
3567 if (Result.isInvalid())
3570 Result = ActOnFinishFullExpr(Result.get());
3571 if (Result.isInvalid())
3573 Throw = Result.get();
3575 QualType ThrowType = Throw->getType();
3576 // Make sure the expression type is an ObjC pointer or "void *".
3577 if (!ThrowType->isDependentType() &&
3578 !ThrowType->isObjCObjectPointerType()) {
3579 const PointerType *PT = ThrowType->getAs<PointerType>();
3580 if (!PT || !PT->getPointeeType()->isVoidType())
3581 return StmtError(Diag(AtLoc, diag::err_objc_throw_expects_object)
3582 << Throw->getType() << Throw->getSourceRange());
3586 return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
3590 Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
3592 if (!getLangOpts().ObjCExceptions)
3593 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
3596 // @throw without an expression designates a rethrow (which must occur
3597 // in the context of an @catch clause).
3598 Scope *AtCatchParent = CurScope;
3599 while (AtCatchParent && !AtCatchParent->isAtCatchScope())
3600 AtCatchParent = AtCatchParent->getParent();
3602 return StmtError(Diag(AtLoc, diag::err_rethrow_used_outside_catch));
3604 return BuildObjCAtThrowStmt(AtLoc, Throw);
3608 Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
3609 ExprResult result = DefaultLvalueConversion(operand);
3610 if (result.isInvalid())
3612 operand = result.get();
3614 // Make sure the expression type is an ObjC pointer or "void *".
3615 QualType type = operand->getType();
3616 if (!type->isDependentType() &&
3617 !type->isObjCObjectPointerType()) {
3618 const PointerType *pointerType = type->getAs<PointerType>();
3619 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) {
3620 if (getLangOpts().CPlusPlus) {
3621 if (RequireCompleteType(atLoc, type,
3622 diag::err_incomplete_receiver_type))
3623 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3624 << type << operand->getSourceRange();
3626 ExprResult result = PerformContextuallyConvertToObjCPointer(operand);
3627 if (result.isInvalid())
3629 if (!result.isUsable())
3630 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3631 << type << operand->getSourceRange();
3633 operand = result.get();
3635 return Diag(atLoc, diag::err_objc_synchronized_expects_object)
3636 << type << operand->getSourceRange();
3641 // The operand to @synchronized is a full-expression.
3642 return ActOnFinishFullExpr(operand);
3646 Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
3648 // We can't jump into or indirect-jump out of a @synchronized block.
3649 getCurFunction()->setHasBranchProtectedScope();
3650 return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
3653 /// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
3654 /// and creates a proper catch handler from them.
3656 Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
3657 Stmt *HandlerBlock) {
3658 // There's nothing to test that ActOnExceptionDecl didn't already test.
3659 return new (Context)
3660 CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(ExDecl), HandlerBlock);
3664 Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
3665 getCurFunction()->setHasBranchProtectedScope();
3666 return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
3670 class CatchHandlerType {
3672 unsigned IsPointer : 1;
3674 // This is a special constructor to be used only with DenseMapInfo's
3675 // getEmptyKey() and getTombstoneKey() functions.
3676 friend struct llvm::DenseMapInfo<CatchHandlerType>;
3677 enum Unique { ForDenseMap };
3678 CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
3681 /// Used when creating a CatchHandlerType from a handler type; will determine
3682 /// whether the type is a pointer or reference and will strip off the top
3683 /// level pointer and cv-qualifiers.
3684 CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
3685 if (QT->isPointerType())
3688 if (IsPointer || QT->isReferenceType())
3689 QT = QT->getPointeeType();
3690 QT = QT.getUnqualifiedType();
3693 /// Used when creating a CatchHandlerType from a base class type; pretends the
3694 /// type passed in had the pointer qualifier, does not need to get an
3695 /// unqualified type.
3696 CatchHandlerType(QualType QT, bool IsPointer)
3697 : QT(QT), IsPointer(IsPointer) {}
3699 QualType underlying() const { return QT; }
3700 bool isPointer() const { return IsPointer; }
3702 friend bool operator==(const CatchHandlerType &LHS,
3703 const CatchHandlerType &RHS) {
3704 // If the pointer qualification does not match, we can return early.
3705 if (LHS.IsPointer != RHS.IsPointer)
3707 // Otherwise, check the underlying type without cv-qualifiers.
3708 return LHS.QT == RHS.QT;
3714 template <> struct DenseMapInfo<CatchHandlerType> {
3715 static CatchHandlerType getEmptyKey() {
3716 return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
3717 CatchHandlerType::ForDenseMap);
3720 static CatchHandlerType getTombstoneKey() {
3721 return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
3722 CatchHandlerType::ForDenseMap);
3725 static unsigned getHashValue(const CatchHandlerType &Base) {
3726 return DenseMapInfo<QualType>::getHashValue(Base.underlying());
3729 static bool isEqual(const CatchHandlerType &LHS,
3730 const CatchHandlerType &RHS) {
3737 class CatchTypePublicBases {
3739 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &TypesToCheck;
3740 const bool CheckAgainstPointer;
3742 CXXCatchStmt *FoundHandler;
3743 CanQualType FoundHandlerType;
3746 CatchTypePublicBases(
3748 const llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> &T, bool C)
3749 : Ctx(Ctx), TypesToCheck(T), CheckAgainstPointer(C),
3750 FoundHandler(nullptr) {}
3752 CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
3753 CanQualType getFoundHandlerType() const { return FoundHandlerType; }
3755 bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
3756 if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
3757 CatchHandlerType Check(S->getType(), CheckAgainstPointer);
3758 const auto &M = TypesToCheck;
3759 auto I = M.find(Check);
3761 FoundHandler = I->second;
3762 FoundHandlerType = Ctx.getCanonicalType(S->getType());
3771 /// ActOnCXXTryBlock - Takes a try compound-statement and a number of
3772 /// handlers and creates a try statement from them.
3773 StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
3774 ArrayRef<Stmt *> Handlers) {
3775 // Don't report an error if 'try' is used in system headers.
3776 if (!getLangOpts().CXXExceptions &&
3777 !getSourceManager().isInSystemHeader(TryLoc))
3778 Diag(TryLoc, diag::err_exceptions_disabled) << "try";
3780 // Exceptions aren't allowed in CUDA device code.
3781 if (getLangOpts().CUDA)
3782 CUDADiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
3783 << "try" << CurrentCUDATarget();
3785 if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
3786 Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
3788 sema::FunctionScopeInfo *FSI = getCurFunction();
3790 // C++ try is incompatible with SEH __try.
3791 if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
3792 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3793 Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
3796 const unsigned NumHandlers = Handlers.size();
3797 assert(!Handlers.empty() &&
3798 "The parser shouldn't call this if there are no handlers.");
3800 llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
3801 for (unsigned i = 0; i < NumHandlers; ++i) {
3802 CXXCatchStmt *H = cast<CXXCatchStmt>(Handlers[i]);
3804 // Diagnose when the handler is a catch-all handler, but it isn't the last
3805 // handler for the try block. [except.handle]p5. Also, skip exception
3806 // declarations that are invalid, since we can't usefully report on them.
3807 if (!H->getExceptionDecl()) {
3808 if (i < NumHandlers - 1)
3809 return StmtError(Diag(H->getLocStart(), diag::err_early_catch_all));
3811 } else if (H->getExceptionDecl()->isInvalidDecl())
3814 // Walk the type hierarchy to diagnose when this type has already been
3815 // handled (duplication), or cannot be handled (derivation inversion). We
3816 // ignore top-level cv-qualifiers, per [except.handle]p3
3817 CatchHandlerType HandlerCHT =
3818 (QualType)Context.getCanonicalType(H->getCaughtType());
3820 // We can ignore whether the type is a reference or a pointer; we need the
3821 // underlying declaration type in order to get at the underlying record
3822 // decl, if there is one.
3823 QualType Underlying = HandlerCHT.underlying();
3824 if (auto *RD = Underlying->getAsCXXRecordDecl()) {
3825 if (!RD->hasDefinition())
3827 // Check that none of the public, unambiguous base classes are in the
3828 // map ([except.handle]p1). Give the base classes the same pointer
3829 // qualification as the original type we are basing off of. This allows
3830 // comparison against the handler type using the same top-level pointer
3831 // as the original type.
3833 Paths.setOrigin(RD);
3834 CatchTypePublicBases CTPB(Context, HandledTypes, HandlerCHT.isPointer());
3835 if (RD->lookupInBases(CTPB, Paths)) {
3836 const CXXCatchStmt *Problem = CTPB.getFoundHandler();
3837 if (!Paths.isAmbiguous(CTPB.getFoundHandlerType())) {
3838 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3839 diag::warn_exception_caught_by_earlier_handler)
3840 << H->getCaughtType();
3841 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3842 diag::note_previous_exception_handler)
3843 << Problem->getCaughtType();
3848 // Add the type the list of ones we have handled; diagnose if we've already
3850 auto R = HandledTypes.insert(std::make_pair(H->getCaughtType(), H));
3852 const CXXCatchStmt *Problem = R.first->second;
3853 Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
3854 diag::warn_exception_caught_by_earlier_handler)
3855 << H->getCaughtType();
3856 Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
3857 diag::note_previous_exception_handler)
3858 << Problem->getCaughtType();
3862 FSI->setHasCXXTry(TryLoc);
3864 return CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers);
3867 StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
3868 Stmt *TryBlock, Stmt *Handler) {
3869 assert(TryBlock && Handler);
3871 sema::FunctionScopeInfo *FSI = getCurFunction();
3873 // SEH __try is incompatible with C++ try. Borland appears to support this,
3875 if (!getLangOpts().Borland) {
3876 if (FSI->FirstCXXTryLoc.isValid()) {
3877 Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
3878 Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
3882 FSI->setHasSEHTry(TryLoc);
3884 // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
3885 // track if they use SEH.
3886 DeclContext *DC = CurContext;
3887 while (DC && !DC->isFunctionOrMethod())
3888 DC = DC->getParent();
3889 FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
3891 FD->setUsesSEHTry(true);
3893 Diag(TryLoc, diag::err_seh_try_outside_functions);
3895 // Reject __try on unsupported targets.
3896 if (!Context.getTargetInfo().isSEHTrySupported())
3897 Diag(TryLoc, diag::err_seh_try_unsupported);
3899 return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
3903 Sema::ActOnSEHExceptBlock(SourceLocation Loc,
3906 assert(FilterExpr && Block);
3908 if(!FilterExpr->getType()->isIntegerType()) {
3909 return StmtError(Diag(FilterExpr->getExprLoc(),
3910 diag::err_filter_expression_integral)
3911 << FilterExpr->getType());
3914 return SEHExceptStmt::Create(Context,Loc,FilterExpr,Block);
3917 void Sema::ActOnStartSEHFinallyBlock() {
3918 CurrentSEHFinally.push_back(CurScope);
3921 void Sema::ActOnAbortSEHFinallyBlock() {
3922 CurrentSEHFinally.pop_back();
3925 StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
3927 CurrentSEHFinally.pop_back();
3928 return SEHFinallyStmt::Create(Context, Loc, Block);
3932 Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
3933 Scope *SEHTryParent = CurScope;
3934 while (SEHTryParent && !SEHTryParent->isSEHTryScope())
3935 SEHTryParent = SEHTryParent->getParent();
3937 return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
3938 CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);
3940 return new (Context) SEHLeaveStmt(Loc);
3943 StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
3945 NestedNameSpecifierLoc QualifierLoc,
3946 DeclarationNameInfo NameInfo,
3949 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
3950 QualifierLoc, NameInfo,
3951 cast<CompoundStmt>(Nested));
3955 StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
3958 UnqualifiedId &Name,
3960 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
3961 SS.getWithLocInContext(Context),
3962 GetNameFromUnqualifiedId(Name),
3967 Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
3968 unsigned NumParams) {
3969 DeclContext *DC = CurContext;
3970 while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
3971 DC = DC->getParent();
3973 RecordDecl *RD = nullptr;
3974 if (getLangOpts().CPlusPlus)
3975 RD = CXXRecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc,
3978 RD = RecordDecl::Create(Context, TTK_Struct, DC, Loc, Loc, /*Id=*/nullptr);
3980 RD->setCapturedRecord();
3983 RD->startDefinition();
3985 assert(NumParams > 0 && "CapturedStmt requires context parameter");
3986 CD = CapturedDecl::Create(Context, CurContext, NumParams);
3991 static void buildCapturedStmtCaptureList(
3992 SmallVectorImpl<CapturedStmt::Capture> &Captures,
3993 SmallVectorImpl<Expr *> &CaptureInits,
3994 ArrayRef<CapturingScopeInfo::Capture> Candidates) {
3996 typedef ArrayRef<CapturingScopeInfo::Capture>::const_iterator CaptureIter;
3997 for (CaptureIter Cap = Candidates.begin(); Cap != Candidates.end(); ++Cap) {
3999 if (Cap->isThisCapture()) {
4000 Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
4001 CapturedStmt::VCK_This));
4002 CaptureInits.push_back(Cap->getInitExpr());
4004 } else if (Cap->isVLATypeCapture()) {
4006 CapturedStmt::Capture(Cap->getLocation(), CapturedStmt::VCK_VLAType));
4007 CaptureInits.push_back(nullptr);
4011 Captures.push_back(CapturedStmt::Capture(Cap->getLocation(),
4012 Cap->isReferenceCapture()
4013 ? CapturedStmt::VCK_ByRef
4014 : CapturedStmt::VCK_ByCopy,
4015 Cap->getVariable()));
4016 CaptureInits.push_back(Cap->getInitExpr());
4020 void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4021 CapturedRegionKind Kind,
4022 unsigned NumParams) {
4023 CapturedDecl *CD = nullptr;
4024 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4026 // Build the context parameter
4027 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4028 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4029 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4031 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4032 ImplicitParamDecl::CapturedContext);
4035 CD->setContextParam(0, Param);
4037 // Enter the capturing scope for this captured region.
4038 PushCapturedRegionScope(CurScope, CD, RD, Kind);
4041 PushDeclContext(CurScope, CD);
4045 PushExpressionEvaluationContext(
4046 ExpressionEvaluationContext::PotentiallyEvaluated);
4049 void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4050 CapturedRegionKind Kind,
4051 ArrayRef<CapturedParamNameType> Params) {
4052 CapturedDecl *CD = nullptr;
4053 RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, Params.size());
4055 // Build the context parameter
4056 DeclContext *DC = CapturedDecl::castToDeclContext(CD);
4057 bool ContextIsFound = false;
4058 unsigned ParamNum = 0;
4059 for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4061 I != E; ++I, ++ParamNum) {
4062 if (I->second.isNull()) {
4063 assert(!ContextIsFound &&
4064 "null type has been found already for '__context' parameter");
4065 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4066 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4068 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4069 ImplicitParamDecl::CapturedContext);
4071 CD->setContextParam(ParamNum, Param);
4072 ContextIsFound = true;
4074 IdentifierInfo *ParamName = &Context.Idents.get(I->first);
4076 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
4077 ImplicitParamDecl::CapturedContext);
4079 CD->setParam(ParamNum, Param);
4082 assert(ContextIsFound && "no null type for '__context' parameter");
4083 if (!ContextIsFound) {
4084 // Add __context implicitly if it is not specified.
4085 IdentifierInfo *ParamName = &Context.Idents.get("__context");
4086 QualType ParamType = Context.getPointerType(Context.getTagDeclType(RD));
4088 ImplicitParamDecl::Create(Context, DC, Loc, ParamName, ParamType,
4089 ImplicitParamDecl::CapturedContext);
4091 CD->setContextParam(ParamNum, Param);
4093 // Enter the capturing scope for this captured region.
4094 PushCapturedRegionScope(CurScope, CD, RD, Kind);
4097 PushDeclContext(CurScope, CD);
4101 PushExpressionEvaluationContext(
4102 ExpressionEvaluationContext::PotentiallyEvaluated);
4105 void Sema::ActOnCapturedRegionError() {
4106 DiscardCleanupsInEvaluationContext();
4107 PopExpressionEvaluationContext();
4109 CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
4110 RecordDecl *Record = RSI->TheRecordDecl;
4111 Record->setInvalidDecl();
4113 SmallVector<Decl*, 4> Fields(Record->fields());
4114 ActOnFields(/*Scope=*/nullptr, Record->getLocation(), Record, Fields,
4115 SourceLocation(), SourceLocation(), /*AttributeList=*/nullptr);
4118 PopFunctionScopeInfo();
4121 StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4122 CapturedRegionScopeInfo *RSI = getCurCapturedRegion();
4124 SmallVector<CapturedStmt::Capture, 4> Captures;
4125 SmallVector<Expr *, 4> CaptureInits;
4126 buildCapturedStmtCaptureList(Captures, CaptureInits, RSI->Captures);
4128 CapturedDecl *CD = RSI->TheCapturedDecl;
4129 RecordDecl *RD = RSI->TheRecordDecl;
4131 CapturedStmt *Res = CapturedStmt::Create(
4132 getASTContext(), S, static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4133 Captures, CaptureInits, CD, RD);
4135 CD->setBody(Res->getCapturedStmt());
4136 RD->completeDefinition();
4138 DiscardCleanupsInEvaluationContext();
4139 PopExpressionEvaluationContext();
4142 PopFunctionScopeInfo();