| //===--- SemaLambda.cpp - Semantic Analysis for C++11 Lambdas -------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements semantic analysis for C++ lambda expressions. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "clang/Sema/DeclSpec.h" |
| #include "TypeLocBuilder.h" |
| #include "clang/AST/ASTLambda.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "clang/Sema/Initialization.h" |
| #include "clang/Sema/Lookup.h" |
| #include "clang/Sema/Scope.h" |
| #include "clang/Sema/ScopeInfo.h" |
| #include "clang/Sema/SemaInternal.h" |
| #include "clang/Sema/SemaLambda.h" |
| using namespace clang; |
| using namespace sema; |
| |
| /// Examines the FunctionScopeInfo stack to determine the nearest |
| /// enclosing lambda (to the current lambda) that is 'capture-ready' for |
| /// the variable referenced in the current lambda (i.e. \p VarToCapture). |
| /// If successful, returns the index into Sema's FunctionScopeInfo stack |
| /// of the capture-ready lambda's LambdaScopeInfo. |
| /// |
| /// Climbs down the stack of lambdas (deepest nested lambda - i.e. current |
| /// lambda - is on top) to determine the index of the nearest enclosing/outer |
| /// lambda that is ready to capture the \p VarToCapture being referenced in |
| /// the current lambda. |
| /// As we climb down the stack, we want the index of the first such lambda - |
| /// that is the lambda with the highest index that is 'capture-ready'. |
| /// |
| /// A lambda 'L' is capture-ready for 'V' (var or this) if: |
| /// - its enclosing context is non-dependent |
| /// - and if the chain of lambdas between L and the lambda in which |
| /// V is potentially used (i.e. the lambda at the top of the scope info |
| /// stack), can all capture or have already captured V. |
| /// If \p VarToCapture is 'null' then we are trying to capture 'this'. |
| /// |
| /// Note that a lambda that is deemed 'capture-ready' still needs to be checked |
| /// for whether it is 'capture-capable' (see |
| /// getStackIndexOfNearestEnclosingCaptureCapableLambda), before it can truly |
| /// capture. |
| /// |
| /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a |
| /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda |
| /// is at the top of the stack and has the highest index. |
| /// \param VarToCapture - the variable to capture. If NULL, capture 'this'. |
| /// |
| /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains |
| /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda |
| /// which is capture-ready. If the return value evaluates to 'false' then |
| /// no lambda is capture-ready for \p VarToCapture. |
| |
| static inline Optional<unsigned> |
| getStackIndexOfNearestEnclosingCaptureReadyLambda( |
| ArrayRef<const clang::sema::FunctionScopeInfo *> FunctionScopes, |
| VarDecl *VarToCapture) { |
| // Label failure to capture. |
| const Optional<unsigned> NoLambdaIsCaptureReady; |
| |
| // Ignore all inner captured regions. |
| unsigned CurScopeIndex = FunctionScopes.size() - 1; |
| while (CurScopeIndex > 0 && isa<clang::sema::CapturedRegionScopeInfo>( |
| FunctionScopes[CurScopeIndex])) |
| --CurScopeIndex; |
| assert( |
| isa<clang::sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]) && |
| "The function on the top of sema's function-info stack must be a lambda"); |
| |
| // If VarToCapture is null, we are attempting to capture 'this'. |
| const bool IsCapturingThis = !VarToCapture; |
| const bool IsCapturingVariable = !IsCapturingThis; |
| |
| // Start with the current lambda at the top of the stack (highest index). |
| DeclContext *EnclosingDC = |
| cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex])->CallOperator; |
| |
| do { |
| const clang::sema::LambdaScopeInfo *LSI = |
| cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]); |
| // IF we have climbed down to an intervening enclosing lambda that contains |
| // the variable declaration - it obviously can/must not capture the |
| // variable. |
| // Since its enclosing DC is dependent, all the lambdas between it and the |
| // innermost nested lambda are dependent (otherwise we wouldn't have |
| // arrived here) - so we don't yet have a lambda that can capture the |
| // variable. |
| if (IsCapturingVariable && |
| VarToCapture->getDeclContext()->Equals(EnclosingDC)) |
| return NoLambdaIsCaptureReady; |
| |
| // For an enclosing lambda to be capture ready for an entity, all |
| // intervening lambda's have to be able to capture that entity. If even |
| // one of the intervening lambda's is not capable of capturing the entity |
| // then no enclosing lambda can ever capture that entity. |
| // For e.g. |
| // const int x = 10; |
| // [=](auto a) { #1 |
| // [](auto b) { #2 <-- an intervening lambda that can never capture 'x' |
| // [=](auto c) { #3 |
| // f(x, c); <-- can not lead to x's speculative capture by #1 or #2 |
| // }; }; }; |
| // If they do not have a default implicit capture, check to see |
| // if the entity has already been explicitly captured. |
| // If even a single dependent enclosing lambda lacks the capability |
| // to ever capture this variable, there is no further enclosing |
| // non-dependent lambda that can capture this variable. |
| if (LSI->ImpCaptureStyle == sema::LambdaScopeInfo::ImpCap_None) { |
| if (IsCapturingVariable && !LSI->isCaptured(VarToCapture)) |
| return NoLambdaIsCaptureReady; |
| if (IsCapturingThis && !LSI->isCXXThisCaptured()) |
| return NoLambdaIsCaptureReady; |
| } |
| EnclosingDC = getLambdaAwareParentOfDeclContext(EnclosingDC); |
| |
| assert(CurScopeIndex); |
| --CurScopeIndex; |
| } while (!EnclosingDC->isTranslationUnit() && |
| EnclosingDC->isDependentContext() && |
| isLambdaCallOperator(EnclosingDC)); |
| |
| assert(CurScopeIndex < (FunctionScopes.size() - 1)); |
| // If the enclosingDC is not dependent, then the immediately nested lambda |
| // (one index above) is capture-ready. |
| if (!EnclosingDC->isDependentContext()) |
| return CurScopeIndex + 1; |
| return NoLambdaIsCaptureReady; |
| } |
| |
| /// Examines the FunctionScopeInfo stack to determine the nearest |
| /// enclosing lambda (to the current lambda) that is 'capture-capable' for |
| /// the variable referenced in the current lambda (i.e. \p VarToCapture). |
| /// If successful, returns the index into Sema's FunctionScopeInfo stack |
| /// of the capture-capable lambda's LambdaScopeInfo. |
| /// |
| /// Given the current stack of lambdas being processed by Sema and |
| /// the variable of interest, to identify the nearest enclosing lambda (to the |
| /// current lambda at the top of the stack) that can truly capture |
| /// a variable, it has to have the following two properties: |
| /// a) 'capture-ready' - be the innermost lambda that is 'capture-ready': |
| /// - climb down the stack (i.e. starting from the innermost and examining |
| /// each outer lambda step by step) checking if each enclosing |
| /// lambda can either implicitly or explicitly capture the variable. |
| /// Record the first such lambda that is enclosed in a non-dependent |
| /// context. If no such lambda currently exists return failure. |
| /// b) 'capture-capable' - make sure the 'capture-ready' lambda can truly |
| /// capture the variable by checking all its enclosing lambdas: |
| /// - check if all outer lambdas enclosing the 'capture-ready' lambda |
| /// identified above in 'a' can also capture the variable (this is done |
| /// via tryCaptureVariable for variables and CheckCXXThisCapture for |
| /// 'this' by passing in the index of the Lambda identified in step 'a') |
| /// |
| /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a |
| /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda |
| /// is at the top of the stack. |
| /// |
| /// \param VarToCapture - the variable to capture. If NULL, capture 'this'. |
| /// |
| /// |
| /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains |
| /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda |
| /// which is capture-capable. If the return value evaluates to 'false' then |
| /// no lambda is capture-capable for \p VarToCapture. |
| |
| Optional<unsigned> clang::getStackIndexOfNearestEnclosingCaptureCapableLambda( |
| ArrayRef<const sema::FunctionScopeInfo *> FunctionScopes, |
| VarDecl *VarToCapture, Sema &S) { |
| |
| const Optional<unsigned> NoLambdaIsCaptureCapable; |
| |
| const Optional<unsigned> OptionalStackIndex = |
| getStackIndexOfNearestEnclosingCaptureReadyLambda(FunctionScopes, |
| VarToCapture); |
| if (!OptionalStackIndex) |
| return NoLambdaIsCaptureCapable; |
| |
| const unsigned IndexOfCaptureReadyLambda = OptionalStackIndex.getValue(); |
| assert(((IndexOfCaptureReadyLambda != (FunctionScopes.size() - 1)) || |
| S.getCurGenericLambda()) && |
| "The capture ready lambda for a potential capture can only be the " |
| "current lambda if it is a generic lambda"); |
| |
| const sema::LambdaScopeInfo *const CaptureReadyLambdaLSI = |
| cast<sema::LambdaScopeInfo>(FunctionScopes[IndexOfCaptureReadyLambda]); |
| |
| // If VarToCapture is null, we are attempting to capture 'this' |
| const bool IsCapturingThis = !VarToCapture; |
| const bool IsCapturingVariable = !IsCapturingThis; |
| |
| if (IsCapturingVariable) { |
| // Check if the capture-ready lambda can truly capture the variable, by |
| // checking whether all enclosing lambdas of the capture-ready lambda allow |
| // the capture - i.e. make sure it is capture-capable. |
| QualType CaptureType, DeclRefType; |
| const bool CanCaptureVariable = |
| !S.tryCaptureVariable(VarToCapture, |
| /*ExprVarIsUsedInLoc*/ SourceLocation(), |
| clang::Sema::TryCapture_Implicit, |
| /*EllipsisLoc*/ SourceLocation(), |
| /*BuildAndDiagnose*/ false, CaptureType, |
| DeclRefType, &IndexOfCaptureReadyLambda); |
| if (!CanCaptureVariable) |
| return NoLambdaIsCaptureCapable; |
| } else { |
| // Check if the capture-ready lambda can truly capture 'this' by checking |
| // whether all enclosing lambdas of the capture-ready lambda can capture |
| // 'this'. |
| const bool CanCaptureThis = |
| !S.CheckCXXThisCapture( |
| CaptureReadyLambdaLSI->PotentialThisCaptureLocation, |
| /*Explicit*/ false, /*BuildAndDiagnose*/ false, |
| &IndexOfCaptureReadyLambda); |
| if (!CanCaptureThis) |
| return NoLambdaIsCaptureCapable; |
| } |
| return IndexOfCaptureReadyLambda; |
| } |
| |
| static inline TemplateParameterList * |
| getGenericLambdaTemplateParameterList(LambdaScopeInfo *LSI, Sema &SemaRef) { |
| if (LSI->GLTemplateParameterList) |
| return LSI->GLTemplateParameterList; |
| |
| if (!LSI->AutoTemplateParams.empty()) { |
| SourceRange IntroRange = LSI->IntroducerRange; |
| SourceLocation LAngleLoc = IntroRange.getBegin(); |
| SourceLocation RAngleLoc = IntroRange.getEnd(); |
| LSI->GLTemplateParameterList = TemplateParameterList::Create( |
| SemaRef.Context, |
| /*Template kw loc*/ SourceLocation(), LAngleLoc, |
| llvm::makeArrayRef((NamedDecl *const *)LSI->AutoTemplateParams.data(), |
| LSI->AutoTemplateParams.size()), |
| RAngleLoc, nullptr); |
| } |
| return LSI->GLTemplateParameterList; |
| } |
| |
| CXXRecordDecl *Sema::createLambdaClosureType(SourceRange IntroducerRange, |
| TypeSourceInfo *Info, |
| bool KnownDependent, |
| LambdaCaptureDefault CaptureDefault) { |
| DeclContext *DC = CurContext; |
| while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext())) |
| DC = DC->getParent(); |
| bool IsGenericLambda = getGenericLambdaTemplateParameterList(getCurLambda(), |
| *this); |
| // Start constructing the lambda class. |
| CXXRecordDecl *Class = CXXRecordDecl::CreateLambda(Context, DC, Info, |
| IntroducerRange.getBegin(), |
| KnownDependent, |
| IsGenericLambda, |
| CaptureDefault); |
| DC->addDecl(Class); |
| |
| return Class; |
| } |
| |
| /// Determine whether the given context is or is enclosed in an inline |
| /// function. |
| static bool isInInlineFunction(const DeclContext *DC) { |
| while (!DC->isFileContext()) { |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) |
| if (FD->isInlined()) |
| return true; |
| |
| DC = DC->getLexicalParent(); |
| } |
| |
| return false; |
| } |
| |
| MangleNumberingContext * |
| Sema::getCurrentMangleNumberContext(const DeclContext *DC, |
| Decl *&ManglingContextDecl) { |
| // Compute the context for allocating mangling numbers in the current |
| // expression, if the ABI requires them. |
| ManglingContextDecl = ExprEvalContexts.back().ManglingContextDecl; |
| |
| enum ContextKind { |
| Normal, |
| DefaultArgument, |
| DataMember, |
| StaticDataMember, |
| InlineVariable, |
| VariableTemplate |
| } Kind = Normal; |
| |
| // Default arguments of member function parameters that appear in a class |
| // definition, as well as the initializers of data members, receive special |
| // treatment. Identify them. |
| if (ManglingContextDecl) { |
| if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(ManglingContextDecl)) { |
| if (const DeclContext *LexicalDC |
| = Param->getDeclContext()->getLexicalParent()) |
| if (LexicalDC->isRecord()) |
| Kind = DefaultArgument; |
| } else if (VarDecl *Var = dyn_cast<VarDecl>(ManglingContextDecl)) { |
| if (Var->getDeclContext()->isRecord()) |
| Kind = StaticDataMember; |
| else if (Var->getMostRecentDecl()->isInline()) |
| Kind = InlineVariable; |
| else if (Var->getDescribedVarTemplate()) |
| Kind = VariableTemplate; |
| else if (auto *VTS = dyn_cast<VarTemplateSpecializationDecl>(Var)) { |
| if (!VTS->isExplicitSpecialization()) |
| Kind = VariableTemplate; |
| } |
| } else if (isa<FieldDecl>(ManglingContextDecl)) { |
| Kind = DataMember; |
| } |
| } |
| |
| // Itanium ABI [5.1.7]: |
| // In the following contexts [...] the one-definition rule requires closure |
| // types in different translation units to "correspond": |
| bool IsInNonspecializedTemplate = |
| inTemplateInstantiation() || CurContext->isDependentContext(); |
| switch (Kind) { |
| case Normal: { |
| // -- the bodies of non-exported nonspecialized template functions |
| // -- the bodies of inline functions |
| if ((IsInNonspecializedTemplate && |
| !(ManglingContextDecl && isa<ParmVarDecl>(ManglingContextDecl))) || |
| isInInlineFunction(CurContext)) { |
| ManglingContextDecl = nullptr; |
| while (auto *CD = dyn_cast<CapturedDecl>(DC)) |
| DC = CD->getParent(); |
| return &Context.getManglingNumberContext(DC); |
| } |
| |
| ManglingContextDecl = nullptr; |
| return nullptr; |
| } |
| |
| case StaticDataMember: |
| // -- the initializers of nonspecialized static members of template classes |
| if (!IsInNonspecializedTemplate) { |
| ManglingContextDecl = nullptr; |
| return nullptr; |
| } |
| // Fall through to get the current context. |
| LLVM_FALLTHROUGH; |
| |
| case DataMember: |
| // -- the in-class initializers of class members |
| case DefaultArgument: |
| // -- default arguments appearing in class definitions |
| case InlineVariable: |
| // -- the initializers of inline variables |
| case VariableTemplate: |
| // -- the initializers of templated variables |
| return &ExprEvalContexts.back().getMangleNumberingContext(Context); |
| } |
| |
| llvm_unreachable("unexpected context"); |
| } |
| |
| MangleNumberingContext & |
| Sema::ExpressionEvaluationContextRecord::getMangleNumberingContext( |
| ASTContext &Ctx) { |
| assert(ManglingContextDecl && "Need to have a context declaration"); |
| if (!MangleNumbering) |
| MangleNumbering = Ctx.createMangleNumberingContext(); |
| return *MangleNumbering; |
| } |
| |
| CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class, |
| SourceRange IntroducerRange, |
| TypeSourceInfo *MethodTypeInfo, |
| SourceLocation EndLoc, |
| ArrayRef<ParmVarDecl *> Params, |
| const bool IsConstexprSpecified) { |
| QualType MethodType = MethodTypeInfo->getType(); |
| TemplateParameterList *TemplateParams = |
| getGenericLambdaTemplateParameterList(getCurLambda(), *this); |
| // If a lambda appears in a dependent context or is a generic lambda (has |
| // template parameters) and has an 'auto' return type, deduce it to a |
| // dependent type. |
| if (Class->isDependentContext() || TemplateParams) { |
| const FunctionProtoType *FPT = MethodType->castAs<FunctionProtoType>(); |
| QualType Result = FPT->getReturnType(); |
| if (Result->isUndeducedType()) { |
| Result = SubstAutoType(Result, Context.DependentTy); |
| MethodType = Context.getFunctionType(Result, FPT->getParamTypes(), |
| FPT->getExtProtoInfo()); |
| } |
| } |
| |
| // C++11 [expr.prim.lambda]p5: |
| // The closure type for a lambda-expression has a public inline function |
| // call operator (13.5.4) whose parameters and return type are described by |
| // the lambda-expression's parameter-declaration-clause and |
| // trailing-return-type respectively. |
| DeclarationName MethodName |
| = Context.DeclarationNames.getCXXOperatorName(OO_Call); |
| DeclarationNameLoc MethodNameLoc; |
| MethodNameLoc.CXXOperatorName.BeginOpNameLoc |
| = IntroducerRange.getBegin().getRawEncoding(); |
| MethodNameLoc.CXXOperatorName.EndOpNameLoc |
| = IntroducerRange.getEnd().getRawEncoding(); |
| CXXMethodDecl *Method |
| = CXXMethodDecl::Create(Context, Class, EndLoc, |
| DeclarationNameInfo(MethodName, |
| IntroducerRange.getBegin(), |
| MethodNameLoc), |
| MethodType, MethodTypeInfo, |
| SC_None, |
| /*isInline=*/true, |
| IsConstexprSpecified, |
| EndLoc); |
| Method->setAccess(AS_public); |
| |
| // Temporarily set the lexical declaration context to the current |
| // context, so that the Scope stack matches the lexical nesting. |
| Method->setLexicalDeclContext(CurContext); |
| // Create a function template if we have a template parameter list |
| FunctionTemplateDecl *const TemplateMethod = TemplateParams ? |
| FunctionTemplateDecl::Create(Context, Class, |
| Method->getLocation(), MethodName, |
| TemplateParams, |
| Method) : nullptr; |
| if (TemplateMethod) { |
| TemplateMethod->setLexicalDeclContext(CurContext); |
| TemplateMethod->setAccess(AS_public); |
| Method->setDescribedFunctionTemplate(TemplateMethod); |
| } |
| |
| // Add parameters. |
| if (!Params.empty()) { |
| Method->setParams(Params); |
| CheckParmsForFunctionDef(Params, |
| /*CheckParameterNames=*/false); |
| |
| for (auto P : Method->parameters()) |
| P->setOwningFunction(Method); |
| } |
| |
| Decl *ManglingContextDecl; |
| if (MangleNumberingContext *MCtx = |
| getCurrentMangleNumberContext(Class->getDeclContext(), |
| ManglingContextDecl)) { |
| unsigned ManglingNumber = MCtx->getManglingNumber(Method); |
| Class->setLambdaMangling(ManglingNumber, ManglingContextDecl); |
| } |
| |
| return Method; |
| } |
| |
| void Sema::buildLambdaScope(LambdaScopeInfo *LSI, |
| CXXMethodDecl *CallOperator, |
| SourceRange IntroducerRange, |
| LambdaCaptureDefault CaptureDefault, |
| SourceLocation CaptureDefaultLoc, |
| bool ExplicitParams, |
| bool ExplicitResultType, |
| bool Mutable) { |
| LSI->CallOperator = CallOperator; |
| CXXRecordDecl *LambdaClass = CallOperator->getParent(); |
| LSI->Lambda = LambdaClass; |
| if (CaptureDefault == LCD_ByCopy) |
| LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByval; |
| else if (CaptureDefault == LCD_ByRef) |
| LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByref; |
| LSI->CaptureDefaultLoc = CaptureDefaultLoc; |
| LSI->IntroducerRange = IntroducerRange; |
| LSI->ExplicitParams = ExplicitParams; |
| LSI->Mutable = Mutable; |
| |
| if (ExplicitResultType) { |
| LSI->ReturnType = CallOperator->getReturnType(); |
| |
| if (!LSI->ReturnType->isDependentType() && |
| !LSI->ReturnType->isVoidType()) { |
| if (RequireCompleteType(CallOperator->getLocStart(), LSI->ReturnType, |
| diag::err_lambda_incomplete_result)) { |
| // Do nothing. |
| } |
| } |
| } else { |
| LSI->HasImplicitReturnType = true; |
| } |
| } |
| |
| void Sema::finishLambdaExplicitCaptures(LambdaScopeInfo *LSI) { |
| LSI->finishedExplicitCaptures(); |
| } |
| |
| void Sema::addLambdaParameters(CXXMethodDecl *CallOperator, Scope *CurScope) { |
| // Introduce our parameters into the function scope |
| for (unsigned p = 0, NumParams = CallOperator->getNumParams(); |
| p < NumParams; ++p) { |
| ParmVarDecl *Param = CallOperator->getParamDecl(p); |
| |
| // If this has an identifier, add it to the scope stack. |
| if (CurScope && Param->getIdentifier()) { |
| CheckShadow(CurScope, Param); |
| |
| PushOnScopeChains(Param, CurScope); |
| } |
| } |
| } |
| |
| /// If this expression is an enumerator-like expression of some type |
| /// T, return the type T; otherwise, return null. |
| /// |
| /// Pointer comparisons on the result here should always work because |
| /// it's derived from either the parent of an EnumConstantDecl |
| /// (i.e. the definition) or the declaration returned by |
| /// EnumType::getDecl() (i.e. the definition). |
| static EnumDecl *findEnumForBlockReturn(Expr *E) { |
| // An expression is an enumerator-like expression of type T if, |
| // ignoring parens and parens-like expressions: |
| E = E->IgnoreParens(); |
| |
| // - it is an enumerator whose enum type is T or |
| if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { |
| if (EnumConstantDecl *D |
| = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { |
| return cast<EnumDecl>(D->getDeclContext()); |
| } |
| return nullptr; |
| } |
| |
| // - it is a comma expression whose RHS is an enumerator-like |
| // expression of type T or |
| if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { |
| if (BO->getOpcode() == BO_Comma) |
| return findEnumForBlockReturn(BO->getRHS()); |
| return nullptr; |
| } |
| |
| // - it is a statement-expression whose value expression is an |
| // enumerator-like expression of type T or |
| if (StmtExpr *SE = dyn_cast<StmtExpr>(E)) { |
| if (Expr *last = dyn_cast_or_null<Expr>(SE->getSubStmt()->body_back())) |
| return findEnumForBlockReturn(last); |
| return nullptr; |
| } |
| |
| // - it is a ternary conditional operator (not the GNU ?: |
| // extension) whose second and third operands are |
| // enumerator-like expressions of type T or |
| if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { |
| if (EnumDecl *ED = findEnumForBlockReturn(CO->getTrueExpr())) |
| if (ED == findEnumForBlockReturn(CO->getFalseExpr())) |
| return ED; |
| return nullptr; |
| } |
| |
| // (implicitly:) |
| // - it is an implicit integral conversion applied to an |
| // enumerator-like expression of type T or |
| if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { |
| // We can sometimes see integral conversions in valid |
| // enumerator-like expressions. |
| if (ICE->getCastKind() == CK_IntegralCast) |
| return findEnumForBlockReturn(ICE->getSubExpr()); |
| |
| // Otherwise, just rely on the type. |
| } |
| |
| // - it is an expression of that formal enum type. |
| if (const EnumType *ET = E->getType()->getAs<EnumType>()) { |
| return ET->getDecl(); |
| } |
| |
| // Otherwise, nope. |
| return nullptr; |
| } |
| |
| /// Attempt to find a type T for which the returned expression of the |
| /// given statement is an enumerator-like expression of that type. |
| static EnumDecl *findEnumForBlockReturn(ReturnStmt *ret) { |
| if (Expr *retValue = ret->getRetValue()) |
| return findEnumForBlockReturn(retValue); |
| return nullptr; |
| } |
| |
| /// Attempt to find a common type T for which all of the returned |
| /// expressions in a block are enumerator-like expressions of that |
| /// type. |
| static EnumDecl *findCommonEnumForBlockReturns(ArrayRef<ReturnStmt*> returns) { |
| ArrayRef<ReturnStmt*>::iterator i = returns.begin(), e = returns.end(); |
| |
| // Try to find one for the first return. |
| EnumDecl *ED = findEnumForBlockReturn(*i); |
| if (!ED) return nullptr; |
| |
| // Check that the rest of the returns have the same enum. |
| for (++i; i != e; ++i) { |
| if (findEnumForBlockReturn(*i) != ED) |
| return nullptr; |
| } |
| |
| // Never infer an anonymous enum type. |
| if (!ED->hasNameForLinkage()) return nullptr; |
| |
| return ED; |
| } |
| |
| /// Adjust the given return statements so that they formally return |
| /// the given type. It should require, at most, an IntegralCast. |
| static void adjustBlockReturnsToEnum(Sema &S, ArrayRef<ReturnStmt*> returns, |
| QualType returnType) { |
| for (ArrayRef<ReturnStmt*>::iterator |
| i = returns.begin(), e = returns.end(); i != e; ++i) { |
| ReturnStmt *ret = *i; |
| Expr *retValue = ret->getRetValue(); |
| if (S.Context.hasSameType(retValue->getType(), returnType)) |
| continue; |
| |
| // Right now we only support integral fixup casts. |
| assert(returnType->isIntegralOrUnscopedEnumerationType()); |
| assert(retValue->getType()->isIntegralOrUnscopedEnumerationType()); |
| |
| ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(retValue); |
| |
| Expr *E = (cleanups ? cleanups->getSubExpr() : retValue); |
| E = ImplicitCastExpr::Create(S.Context, returnType, CK_IntegralCast, |
| E, /*base path*/ nullptr, VK_RValue); |
| if (cleanups) { |
| cleanups->setSubExpr(E); |
| } else { |
| ret->setRetValue(E); |
| } |
| } |
| } |
| |
| void Sema::deduceClosureReturnType(CapturingScopeInfo &CSI) { |
| assert(CSI.HasImplicitReturnType); |
| // If it was ever a placeholder, it had to been deduced to DependentTy. |
| assert(CSI.ReturnType.isNull() || !CSI.ReturnType->isUndeducedType()); |
| assert((!isa<LambdaScopeInfo>(CSI) || !getLangOpts().CPlusPlus14) && |
| "lambda expressions use auto deduction in C++14 onwards"); |
| |
| // C++ core issue 975: |
| // If a lambda-expression does not include a trailing-return-type, |
| // it is as if the trailing-return-type denotes the following type: |
| // - if there are no return statements in the compound-statement, |
| // or all return statements return either an expression of type |
| // void or no expression or braced-init-list, the type void; |
| // - otherwise, if all return statements return an expression |
| // and the types of the returned expressions after |
| // lvalue-to-rvalue conversion (4.1 [conv.lval]), |
| // array-to-pointer conversion (4.2 [conv.array]), and |
| // function-to-pointer conversion (4.3 [conv.func]) are the |
| // same, that common type; |
| // - otherwise, the program is ill-formed. |
| // |
| // C++ core issue 1048 additionally removes top-level cv-qualifiers |
| // from the types of returned expressions to match the C++14 auto |
| // deduction rules. |
| // |
| // In addition, in blocks in non-C++ modes, if all of the return |
| // statements are enumerator-like expressions of some type T, where |
| // T has a name for linkage, then we infer the return type of the |
| // block to be that type. |
| |
| // First case: no return statements, implicit void return type. |
| ASTContext &Ctx = getASTContext(); |
| if (CSI.Returns.empty()) { |
| // It's possible there were simply no /valid/ return statements. |
| // In this case, the first one we found may have at least given us a type. |
| if (CSI.ReturnType.isNull()) |
| CSI.ReturnType = Ctx.VoidTy; |
| return; |
| } |
| |
| // Second case: at least one return statement has dependent type. |
| // Delay type checking until instantiation. |
| assert(!CSI.ReturnType.isNull() && "We should have a tentative return type."); |
| if (CSI.ReturnType->isDependentType()) |
| return; |
| |
| // Try to apply the enum-fuzz rule. |
| if (!getLangOpts().CPlusPlus) { |
| assert(isa<BlockScopeInfo>(CSI)); |
| const EnumDecl *ED = findCommonEnumForBlockReturns(CSI.Returns); |
| if (ED) { |
| CSI.ReturnType = Context.getTypeDeclType(ED); |
| adjustBlockReturnsToEnum(*this, CSI.Returns, CSI.ReturnType); |
| return; |
| } |
| } |
| |
| // Third case: only one return statement. Don't bother doing extra work! |
| if (CSI.Returns.size() == 1) |
| return; |
| |
| // General case: many return statements. |
| // Check that they all have compatible return types. |
| |
| // We require the return types to strictly match here. |
| // Note that we've already done the required promotions as part of |
| // processing the return statement. |
| for (const ReturnStmt *RS : CSI.Returns) { |
| const Expr *RetE = RS->getRetValue(); |
| |
| QualType ReturnType = |
| (RetE ? RetE->getType() : Context.VoidTy).getUnqualifiedType(); |
| if (Context.getCanonicalFunctionResultType(ReturnType) == |
| Context.getCanonicalFunctionResultType(CSI.ReturnType)) { |
| // Use the return type with the strictest possible nullability annotation. |
| auto RetTyNullability = ReturnType->getNullability(Ctx); |
| auto BlockNullability = CSI.ReturnType->getNullability(Ctx); |
| if (BlockNullability && |
| (!RetTyNullability || |
| hasWeakerNullability(*RetTyNullability, *BlockNullability))) |
| CSI.ReturnType = ReturnType; |
| continue; |
| } |
| |
| // FIXME: This is a poor diagnostic for ReturnStmts without expressions. |
| // TODO: It's possible that the *first* return is the divergent one. |
| Diag(RS->getLocStart(), |
| diag::err_typecheck_missing_return_type_incompatible) |
| << ReturnType << CSI.ReturnType |
| << isa<LambdaScopeInfo>(CSI); |
| // Continue iterating so that we keep emitting diagnostics. |
| } |
| } |
| |
| QualType Sema::buildLambdaInitCaptureInitialization(SourceLocation Loc, |
| bool ByRef, |
| IdentifierInfo *Id, |
| bool IsDirectInit, |
| Expr *&Init) { |
| // Create an 'auto' or 'auto&' TypeSourceInfo that we can use to |
| // deduce against. |
| QualType DeductType = Context.getAutoDeductType(); |
| TypeLocBuilder TLB; |
| TLB.pushTypeSpec(DeductType).setNameLoc(Loc); |
| if (ByRef) { |
| DeductType = BuildReferenceType(DeductType, true, Loc, Id); |
| assert(!DeductType.isNull() && "can't build reference to auto"); |
| TLB.push<ReferenceTypeLoc>(DeductType).setSigilLoc(Loc); |
| } |
| TypeSourceInfo *TSI = TLB.getTypeSourceInfo(Context, DeductType); |
| |
| // Deduce the type of the init capture. |
| QualType DeducedType = deduceVarTypeFromInitializer( |
| /*VarDecl*/nullptr, DeclarationName(Id), DeductType, TSI, |
| SourceRange(Loc, Loc), IsDirectInit, Init); |
| if (DeducedType.isNull()) |
| return QualType(); |
| |
| // Are we a non-list direct initialization? |
| ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init); |
| |
| // Perform initialization analysis and ensure any implicit conversions |
| // (such as lvalue-to-rvalue) are enforced. |
| InitializedEntity Entity = |
| InitializedEntity::InitializeLambdaCapture(Id, DeducedType, Loc); |
| InitializationKind Kind = |
| IsDirectInit |
| ? (CXXDirectInit ? InitializationKind::CreateDirect( |
| Loc, Init->getLocStart(), Init->getLocEnd()) |
| : InitializationKind::CreateDirectList(Loc)) |
| : InitializationKind::CreateCopy(Loc, Init->getLocStart()); |
| |
| MultiExprArg Args = Init; |
| if (CXXDirectInit) |
| Args = |
| MultiExprArg(CXXDirectInit->getExprs(), CXXDirectInit->getNumExprs()); |
| QualType DclT; |
| InitializationSequence InitSeq(*this, Entity, Kind, Args); |
| ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT); |
| |
| if (Result.isInvalid()) |
| return QualType(); |
| Init = Result.getAs<Expr>(); |
| |
| // The init-capture initialization is a full-expression that must be |
| // processed as one before we enter the declcontext of the lambda's |
| // call-operator. |
| Result = ActOnFinishFullExpr(Init, Loc, /*DiscardedValue*/ false, |
| /*IsConstexpr*/ false, |
| /*IsLambdaInitCaptureInitializer*/ true); |
| if (Result.isInvalid()) |
| return QualType(); |
| |
| Init = Result.getAs<Expr>(); |
| return DeducedType; |
| } |
| |
| VarDecl *Sema::createLambdaInitCaptureVarDecl(SourceLocation Loc, |
| QualType InitCaptureType, |
| IdentifierInfo *Id, |
| unsigned InitStyle, Expr *Init) { |
| TypeSourceInfo *TSI = Context.getTrivialTypeSourceInfo(InitCaptureType, |
| Loc); |
| // Create a dummy variable representing the init-capture. This is not actually |
| // used as a variable, and only exists as a way to name and refer to the |
| // init-capture. |
| // FIXME: Pass in separate source locations for '&' and identifier. |
| VarDecl *NewVD = VarDecl::Create(Context, CurContext, Loc, |
| Loc, Id, InitCaptureType, TSI, SC_Auto); |
| NewVD->setInitCapture(true); |
| NewVD->setReferenced(true); |
| // FIXME: Pass in a VarDecl::InitializationStyle. |
| NewVD->setInitStyle(static_cast<VarDecl::InitializationStyle>(InitStyle)); |
| NewVD->markUsed(Context); |
| NewVD->setInit(Init); |
| return NewVD; |
| } |
| |
| FieldDecl *Sema::buildInitCaptureField(LambdaScopeInfo *LSI, VarDecl *Var) { |
| FieldDecl *Field = FieldDecl::Create( |
| Context, LSI->Lambda, Var->getLocation(), Var->getLocation(), |
| nullptr, Var->getType(), Var->getTypeSourceInfo(), nullptr, false, |
| ICIS_NoInit); |
| Field->setImplicit(true); |
| Field->setAccess(AS_private); |
| LSI->Lambda->addDecl(Field); |
| |
| LSI->addCapture(Var, /*isBlock*/false, Var->getType()->isReferenceType(), |
| /*isNested*/false, Var->getLocation(), SourceLocation(), |
| Var->getType(), Var->getInit()); |
| return Field; |
| } |
| |
| void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro, |
| Declarator &ParamInfo, |
| Scope *CurScope) { |
| // Determine if we're within a context where we know that the lambda will |
| // be dependent, because there are template parameters in scope. |
| bool KnownDependent = false; |
| LambdaScopeInfo *const LSI = getCurLambda(); |
| assert(LSI && "LambdaScopeInfo should be on stack!"); |
| |
| // The lambda-expression's closure type might be dependent even if its |
| // semantic context isn't, if it appears within a default argument of a |
| // function template. |
| if (CurScope->getTemplateParamParent()) |
| KnownDependent = true; |
| |
| // Determine the signature of the call operator. |
| TypeSourceInfo *MethodTyInfo; |
| bool ExplicitParams = true; |
| bool ExplicitResultType = true; |
| bool ContainsUnexpandedParameterPack = false; |
| SourceLocation EndLoc; |
| SmallVector<ParmVarDecl *, 8> Params; |
| if (ParamInfo.getNumTypeObjects() == 0) { |
| // C++11 [expr.prim.lambda]p4: |
| // If a lambda-expression does not include a lambda-declarator, it is as |
| // if the lambda-declarator were (). |
| FunctionProtoType::ExtProtoInfo EPI(Context.getDefaultCallingConvention( |
| /*IsVariadic=*/false, /*IsCXXMethod=*/true)); |
| EPI.HasTrailingReturn = true; |
| EPI.TypeQuals |= DeclSpec::TQ_const; |
| // C++1y [expr.prim.lambda]: |
| // The lambda return type is 'auto', which is replaced by the |
| // trailing-return type if provided and/or deduced from 'return' |
| // statements |
| // We don't do this before C++1y, because we don't support deduced return |
| // types there. |
| QualType DefaultTypeForNoTrailingReturn = |
| getLangOpts().CPlusPlus14 ? Context.getAutoDeductType() |
| : Context.DependentTy; |
| QualType MethodTy = |
| Context.getFunctionType(DefaultTypeForNoTrailingReturn, None, EPI); |
| MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy); |
| ExplicitParams = false; |
| ExplicitResultType = false; |
| EndLoc = Intro.Range.getEnd(); |
| } else { |
| assert(ParamInfo.isFunctionDeclarator() && |
| "lambda-declarator is a function"); |
| DeclaratorChunk::FunctionTypeInfo &FTI = ParamInfo.getFunctionTypeInfo(); |
| |
| // C++11 [expr.prim.lambda]p5: |
| // This function call operator is declared const (9.3.1) if and only if |
| // the lambda-expression's parameter-declaration-clause is not followed |
| // by mutable. It is neither virtual nor declared volatile. [...] |
| if (!FTI.hasMutableQualifier()) |
| FTI.TypeQuals |= DeclSpec::TQ_const; |
| |
| MethodTyInfo = GetTypeForDeclarator(ParamInfo, CurScope); |
| assert(MethodTyInfo && "no type from lambda-declarator"); |
| EndLoc = ParamInfo.getSourceRange().getEnd(); |
| |
| ExplicitResultType = FTI.hasTrailingReturnType(); |
| |
| if (FTIHasNonVoidParameters(FTI)) { |
| Params.reserve(FTI.NumParams); |
| for (unsigned i = 0, e = FTI.NumParams; i != e; ++i) |
| Params.push_back(cast<ParmVarDecl>(FTI.Params[i].Param)); |
| } |
| |
| // Check for unexpanded parameter packs in the method type. |
| if (MethodTyInfo->getType()->containsUnexpandedParameterPack()) |
| ContainsUnexpandedParameterPack = true; |
| } |
| |
| CXXRecordDecl *Class = createLambdaClosureType(Intro.Range, MethodTyInfo, |
| KnownDependent, Intro.Default); |
| |
| CXXMethodDecl *Method = |
| startLambdaDefinition(Class, Intro.Range, MethodTyInfo, EndLoc, Params, |
| ParamInfo.getDeclSpec().isConstexprSpecified()); |
| if (ExplicitParams) |
| CheckCXXDefaultArguments(Method); |
| |
| // This represents the function body for the lambda function, check if we |
| // have to apply optnone due to a pragma. |
| AddRangeBasedOptnone(Method); |
| |
| // code_seg attribute on lambda apply to the method. |
| if (Attr *A = getImplicitCodeSegOrSectionAttrForFunction(Method, /*IsDefinition=*/true)) |
| Method->addAttr(A); |
| |
| // Attributes on the lambda apply to the method. |
| ProcessDeclAttributes(CurScope, Method, ParamInfo); |
| |
| // CUDA lambdas get implicit attributes based on the scope in which they're |
| // declared. |
| if (getLangOpts().CUDA) |
| CUDASetLambdaAttrs(Method); |
| |
| // Introduce the function call operator as the current declaration context. |
| PushDeclContext(CurScope, Method); |
| |
| // Build the lambda scope. |
| buildLambdaScope(LSI, Method, Intro.Range, Intro.Default, Intro.DefaultLoc, |
| ExplicitParams, ExplicitResultType, !Method->isConst()); |
| |
| // C++11 [expr.prim.lambda]p9: |
| // A lambda-expression whose smallest enclosing scope is a block scope is a |
| // local lambda expression; any other lambda expression shall not have a |
| // capture-default or simple-capture in its lambda-introducer. |
| // |
| // For simple-captures, this is covered by the check below that any named |
| // entity is a variable that can be captured. |
| // |
| // For DR1632, we also allow a capture-default in any context where we can |
| // odr-use 'this' (in particular, in a default initializer for a non-static |
| // data member). |
| if (Intro.Default != LCD_None && !Class->getParent()->isFunctionOrMethod() && |
| (getCurrentThisType().isNull() || |
| CheckCXXThisCapture(SourceLocation(), /*Explicit*/true, |
| /*BuildAndDiagnose*/false))) |
| Diag(Intro.DefaultLoc, diag::err_capture_default_non_local); |
| |
| // Distinct capture names, for diagnostics. |
| llvm::SmallSet<IdentifierInfo*, 8> CaptureNames; |
| |
| // Handle explicit captures. |
| SourceLocation PrevCaptureLoc |
| = Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc; |
| for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E; |
| PrevCaptureLoc = C->Loc, ++C) { |
| if (C->Kind == LCK_This || C->Kind == LCK_StarThis) { |
| if (C->Kind == LCK_StarThis) |
| Diag(C->Loc, !getLangOpts().CPlusPlus17 |
| ? diag::ext_star_this_lambda_capture_cxx17 |
| : diag::warn_cxx14_compat_star_this_lambda_capture); |
| |
| // C++11 [expr.prim.lambda]p8: |
| // An identifier or this shall not appear more than once in a |
| // lambda-capture. |
| if (LSI->isCXXThisCaptured()) { |
| Diag(C->Loc, diag::err_capture_more_than_once) |
| << "'this'" << SourceRange(LSI->getCXXThisCapture().getLocation()) |
| << FixItHint::CreateRemoval( |
| SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc)); |
| continue; |
| } |
| |
| // C++2a [expr.prim.lambda]p8: |
| // If a lambda-capture includes a capture-default that is =, |
| // each simple-capture of that lambda-capture shall be of the form |
| // "&identifier", "this", or "* this". [ Note: The form [&,this] is |
| // redundant but accepted for compatibility with ISO C++14. --end note ] |
| if (Intro.Default == LCD_ByCopy && C->Kind != LCK_StarThis) |
| Diag(C->Loc, !getLangOpts().CPlusPlus2a |
| ? diag::ext_equals_this_lambda_capture_cxx2a |
| : diag::warn_cxx17_compat_equals_this_lambda_capture); |
| |
| // C++11 [expr.prim.lambda]p12: |
| // If this is captured by a local lambda expression, its nearest |
| // enclosing function shall be a non-static member function. |
| QualType ThisCaptureType = getCurrentThisType(); |
| if (ThisCaptureType.isNull()) { |
| Diag(C->Loc, diag::err_this_capture) << true; |
| continue; |
| } |
| |
| CheckCXXThisCapture(C->Loc, /*Explicit=*/true, /*BuildAndDiagnose*/ true, |
| /*FunctionScopeIndexToStopAtPtr*/ nullptr, |
| C->Kind == LCK_StarThis); |
| if (!LSI->Captures.empty()) |
| LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange; |
| continue; |
| } |
| |
| assert(C->Id && "missing identifier for capture"); |
| |
| if (C->Init.isInvalid()) |
| continue; |
| |
| VarDecl *Var = nullptr; |
| if (C->Init.isUsable()) { |
| Diag(C->Loc, getLangOpts().CPlusPlus14 |
| ? diag::warn_cxx11_compat_init_capture |
| : diag::ext_init_capture); |
| |
| if (C->Init.get()->containsUnexpandedParameterPack()) |
| ContainsUnexpandedParameterPack = true; |
| // If the initializer expression is usable, but the InitCaptureType |
| // is not, then an error has occurred - so ignore the capture for now. |
| // for e.g., [n{0}] { }; <-- if no <initializer_list> is included. |
| // FIXME: we should create the init capture variable and mark it invalid |
| // in this case. |
| if (C->InitCaptureType.get().isNull()) |
| continue; |
| |
| unsigned InitStyle; |
| switch (C->InitKind) { |
| case LambdaCaptureInitKind::NoInit: |
| llvm_unreachable("not an init-capture?"); |
| case LambdaCaptureInitKind::CopyInit: |
| InitStyle = VarDecl::CInit; |
| break; |
| case LambdaCaptureInitKind::DirectInit: |
| InitStyle = VarDecl::CallInit; |
| break; |
| case LambdaCaptureInitKind::ListInit: |
| InitStyle = VarDecl::ListInit; |
| break; |
| } |
| Var = createLambdaInitCaptureVarDecl(C->Loc, C->InitCaptureType.get(), |
| C->Id, InitStyle, C->Init.get()); |
| // C++1y [expr.prim.lambda]p11: |
| // An init-capture behaves as if it declares and explicitly |
| // captures a variable [...] whose declarative region is the |
| // lambda-expression's compound-statement |
| if (Var) |
| PushOnScopeChains(Var, CurScope, false); |
| } else { |
| assert(C->InitKind == LambdaCaptureInitKind::NoInit && |
| "init capture has valid but null init?"); |
| |
| // C++11 [expr.prim.lambda]p8: |
| // If a lambda-capture includes a capture-default that is &, the |
| // identifiers in the lambda-capture shall not be preceded by &. |
| // If a lambda-capture includes a capture-default that is =, [...] |
| // each identifier it contains shall be preceded by &. |
| if (C->Kind == LCK_ByRef && Intro.Default == LCD_ByRef) { |
| Diag(C->Loc, diag::err_reference_capture_with_reference_default) |
| << FixItHint::CreateRemoval( |
| SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc)); |
| continue; |
| } else if (C->Kind == LCK_ByCopy && Intro.Default == LCD_ByCopy) { |
| Diag(C->Loc, diag::err_copy_capture_with_copy_default) |
| << FixItHint::CreateRemoval( |
| SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc)); |
| continue; |
| } |
| |
| // C++11 [expr.prim.lambda]p10: |
| // The identifiers in a capture-list are looked up using the usual |
| // rules for unqualified name lookup (3.4.1) |
| DeclarationNameInfo Name(C->Id, C->Loc); |
| LookupResult R(*this, Name, LookupOrdinaryName); |
| LookupName(R, CurScope); |
| if (R.isAmbiguous()) |
| continue; |
| if (R.empty()) { |
| // FIXME: Disable corrections that would add qualification? |
| CXXScopeSpec ScopeSpec; |
| if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R, |
| llvm::make_unique<DeclFilterCCC<VarDecl>>())) |
| continue; |
| } |
| |
| Var = R.getAsSingle<VarDecl>(); |
| if (Var && DiagnoseUseOfDecl(Var, C->Loc)) |
| continue; |
| } |
| |
| // C++11 [expr.prim.lambda]p8: |
| // An identifier or this shall not appear more than once in a |
| // lambda-capture. |
| if (!CaptureNames.insert(C->Id).second) { |
| if (Var && LSI->isCaptured(Var)) { |
| Diag(C->Loc, diag::err_capture_more_than_once) |
| << C->Id << SourceRange(LSI->getCapture(Var).getLocation()) |
| << FixItHint::CreateRemoval( |
| SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc)); |
| } else |
| // Previous capture captured something different (one or both was |
| // an init-cpature): no fixit. |
| Diag(C->Loc, diag::err_capture_more_than_once) << C->Id; |
| continue; |
| } |
| |
| // C++11 [expr.prim.lambda]p10: |
| // [...] each such lookup shall find a variable with automatic storage |
| // duration declared in the reaching scope of the local lambda expression. |
| // Note that the 'reaching scope' check happens in tryCaptureVariable(). |
| if (!Var) { |
| Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id; |
| continue; |
| } |
| |
| // Ignore invalid decls; they'll just confuse the code later. |
| if (Var->isInvalidDecl()) |
| continue; |
| |
| if (!Var->hasLocalStorage()) { |
| Diag(C->Loc, diag::err_capture_non_automatic_variable) << C->Id; |
| Diag(Var->getLocation(), diag::note_previous_decl) << C->Id; |
| continue; |
| } |
| |
| // C++11 [expr.prim.lambda]p23: |
| // A capture followed by an ellipsis is a pack expansion (14.5.3). |
| SourceLocation EllipsisLoc; |
| if (C->EllipsisLoc.isValid()) { |
| if (Var->isParameterPack()) { |
| EllipsisLoc = C->EllipsisLoc; |
| } else { |
| Diag(C->EllipsisLoc, diag::err_pack_expansion_without_parameter_packs) |
| << SourceRange(C->Loc); |
| |
| // Just ignore the ellipsis. |
| } |
| } else if (Var->isParameterPack()) { |
| ContainsUnexpandedParameterPack = true; |
| } |
| |
| if (C->Init.isUsable()) { |
| buildInitCaptureField(LSI, Var); |
| } else { |
| TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef : |
| TryCapture_ExplicitByVal; |
| tryCaptureVariable(Var, C->Loc, Kind, EllipsisLoc); |
| } |
| if (!LSI->Captures.empty()) |
| LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange; |
| } |
| finishLambdaExplicitCaptures(LSI); |
| |
| LSI->ContainsUnexpandedParameterPack = ContainsUnexpandedParameterPack; |
| |
| // Add lambda parameters into scope. |
| addLambdaParameters(Method, CurScope); |
| |
| // Enter a new evaluation context to insulate the lambda from any |
| // cleanups from the enclosing full-expression. |
| PushExpressionEvaluationContext( |
| ExpressionEvaluationContext::PotentiallyEvaluated); |
| } |
| |
| void Sema::ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope, |
| bool IsInstantiation) { |
| LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(FunctionScopes.back()); |
| |
| // Leave the expression-evaluation context. |
| DiscardCleanupsInEvaluationContext(); |
| PopExpressionEvaluationContext(); |
| |
| // Leave the context of the lambda. |
| if (!IsInstantiation) |
| PopDeclContext(); |
| |
| // Finalize the lambda. |
| CXXRecordDecl *Class = LSI->Lambda; |
| Class->setInvalidDecl(); |
| SmallVector<Decl*, 4> Fields(Class->fields()); |
| ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(), |
| SourceLocation(), ParsedAttributesView()); |
| CheckCompletedCXXClass(Class); |
| |
| PopFunctionScopeInfo(); |
| } |
| |
| QualType Sema::getLambdaConversionFunctionResultType( |
| const FunctionProtoType *CallOpProto) { |
| // The function type inside the pointer type is the same as the call |
| // operator with some tweaks. The calling convention is the default free |
| // function convention, and the type qualifications are lost. |
| const FunctionProtoType::ExtProtoInfo CallOpExtInfo = |
| CallOpProto->getExtProtoInfo(); |
| FunctionProtoType::ExtProtoInfo InvokerExtInfo = CallOpExtInfo; |
| CallingConv CC = Context.getDefaultCallingConvention( |
| CallOpProto->isVariadic(), /*IsCXXMethod=*/false); |
| InvokerExtInfo.ExtInfo = InvokerExtInfo.ExtInfo.withCallingConv(CC); |
| InvokerExtInfo.TypeQuals = 0; |
| assert(InvokerExtInfo.RefQualifier == RQ_None && |
| "Lambda's call operator should not have a reference qualifier"); |
| return Context.getFunctionType(CallOpProto->getReturnType(), |
| CallOpProto->getParamTypes(), InvokerExtInfo); |
| } |
| |
| /// Add a lambda's conversion to function pointer, as described in |
| /// C++11 [expr.prim.lambda]p6. |
| static void addFunctionPointerConversion(Sema &S, |
| SourceRange IntroducerRange, |
| CXXRecordDecl *Class, |
| CXXMethodDecl *CallOperator) { |
| // This conversion is explicitly disabled if the lambda's function has |
| // pass_object_size attributes on any of its parameters. |
| auto HasPassObjectSizeAttr = [](const ParmVarDecl *P) { |
| return P->hasAttr<PassObjectSizeAttr>(); |
| }; |
| if (llvm::any_of(CallOperator->parameters(), HasPassObjectSizeAttr)) |
| return; |
| |
| // Add the conversion to function pointer. |
| QualType InvokerFunctionTy = S.getLambdaConversionFunctionResultType( |
| CallOperator->getType()->castAs<FunctionProtoType>()); |
| QualType PtrToFunctionTy = S.Context.getPointerType(InvokerFunctionTy); |
| |
| // Create the type of the conversion function. |
| FunctionProtoType::ExtProtoInfo ConvExtInfo( |
| S.Context.getDefaultCallingConvention( |
| /*IsVariadic=*/false, /*IsCXXMethod=*/true)); |
| // The conversion function is always const. |
| ConvExtInfo.TypeQuals = Qualifiers::Const; |
| QualType ConvTy = |
| S.Context.getFunctionType(PtrToFunctionTy, None, ConvExtInfo); |
| |
| SourceLocation Loc = IntroducerRange.getBegin(); |
| DeclarationName ConversionName |
| = S.Context.DeclarationNames.getCXXConversionFunctionName( |
| S.Context.getCanonicalType(PtrToFunctionTy)); |
| DeclarationNameLoc ConvNameLoc; |
| // Construct a TypeSourceInfo for the conversion function, and wire |
| // all the parameters appropriately for the FunctionProtoTypeLoc |
| // so that everything works during transformation/instantiation of |
| // generic lambdas. |
| // The main reason for wiring up the parameters of the conversion |
| // function with that of the call operator is so that constructs |
| // like the following work: |
| // auto L = [](auto b) { <-- 1 |
| // return [](auto a) -> decltype(a) { <-- 2 |
| // return a; |
| // }; |
| // }; |
| // int (*fp)(int) = L(5); |
| // Because the trailing return type can contain DeclRefExprs that refer |
| // to the original call operator's variables, we hijack the call |
| // operators ParmVarDecls below. |
| TypeSourceInfo *ConvNamePtrToFunctionTSI = |
| S.Context.getTrivialTypeSourceInfo(PtrToFunctionTy, Loc); |
| ConvNameLoc.NamedType.TInfo = ConvNamePtrToFunctionTSI; |
| |
| // The conversion function is a conversion to a pointer-to-function. |
| TypeSourceInfo *ConvTSI = S.Context.getTrivialTypeSourceInfo(ConvTy, Loc); |
| FunctionProtoTypeLoc ConvTL = |
| ConvTSI->getTypeLoc().getAs<FunctionProtoTypeLoc>(); |
| // Get the result of the conversion function which is a pointer-to-function. |
| PointerTypeLoc PtrToFunctionTL = |
| ConvTL.getReturnLoc().getAs<PointerTypeLoc>(); |
| // Do the same for the TypeSourceInfo that is used to name the conversion |
| // operator. |
| PointerTypeLoc ConvNamePtrToFunctionTL = |
| ConvNamePtrToFunctionTSI->getTypeLoc().getAs<PointerTypeLoc>(); |
| |
| // Get the underlying function types that the conversion function will |
| // be converting to (should match the type of the call operator). |
| FunctionProtoTypeLoc CallOpConvTL = |
| PtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>(); |
| FunctionProtoTypeLoc CallOpConvNameTL = |
| ConvNamePtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>(); |
| |
| // Wire up the FunctionProtoTypeLocs with the call operator's parameters. |
| // These parameter's are essentially used to transform the name and |
| // the type of the conversion operator. By using the same parameters |
| // as the call operator's we don't have to fix any back references that |
| // the trailing return type of the call operator's uses (such as |
| // decltype(some_type<decltype(a)>::type{} + decltype(a){}) etc.) |
| // - we can simply use the return type of the call operator, and |
| // everything should work. |
| SmallVector<ParmVarDecl *, 4> InvokerParams; |
| for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) { |
| ParmVarDecl *From = CallOperator->getParamDecl(I); |
| |
| InvokerParams.push_back(ParmVarDecl::Create(S.Context, |
| // Temporarily add to the TU. This is set to the invoker below. |
| S.Context.getTranslationUnitDecl(), |
| From->getLocStart(), |
| From->getLocation(), |
| From->getIdentifier(), |
| From->getType(), |
| From->getTypeSourceInfo(), |
| From->getStorageClass(), |
| /*DefaultArg=*/nullptr)); |
| CallOpConvTL.setParam(I, From); |
| CallOpConvNameTL.setParam(I, From); |
| } |
| |
| CXXConversionDecl *Conversion |
| = CXXConversionDecl::Create(S.Context, Class, Loc, |
| DeclarationNameInfo(ConversionName, |
| Loc, ConvNameLoc), |
| ConvTy, |
| ConvTSI, |
| /*isInline=*/true, /*isExplicit=*/false, |
| /*isConstexpr=*/S.getLangOpts().CPlusPlus17, |
| CallOperator->getBody()->getLocEnd()); |
| Conversion->setAccess(AS_public); |
| Conversion->setImplicit(true); |
| |
| if (Class->isGenericLambda()) { |
| // Create a template version of the conversion operator, using the template |
| // parameter list of the function call operator. |
| FunctionTemplateDecl *TemplateCallOperator = |
| CallOperator->getDescribedFunctionTemplate(); |
| FunctionTemplateDecl *ConversionTemplate = |
| FunctionTemplateDecl::Create(S.Context, Class, |
| Loc, ConversionName, |
| TemplateCallOperator->getTemplateParameters(), |
| Conversion); |
| ConversionTemplate->setAccess(AS_public); |
| ConversionTemplate->setImplicit(true); |
| Conversion->setDescribedFunctionTemplate(ConversionTemplate); |
| Class->addDecl(ConversionTemplate); |
| } else |
| Class->addDecl(Conversion); |
| // Add a non-static member function that will be the result of |
| // the conversion with a certain unique ID. |
| DeclarationName InvokerName = &S.Context.Idents.get( |
| getLambdaStaticInvokerName()); |
| // FIXME: Instead of passing in the CallOperator->getTypeSourceInfo() |
| // we should get a prebuilt TrivialTypeSourceInfo from Context |
| // using FunctionTy & Loc and get its TypeLoc as a FunctionProtoTypeLoc |
| // then rewire the parameters accordingly, by hoisting up the InvokeParams |
| // loop below and then use its Params to set Invoke->setParams(...) below. |
| // This would avoid the 'const' qualifier of the calloperator from |
| // contaminating the type of the invoker, which is currently adjusted |
| // in SemaTemplateDeduction.cpp:DeduceTemplateArguments. Fixing the |
| // trailing return type of the invoker would require a visitor to rebuild |
| // the trailing return type and adjusting all back DeclRefExpr's to refer |
| // to the new static invoker parameters - not the call operator's. |
| CXXMethodDecl *Invoke |
| = CXXMethodDecl::Create(S.Context, Class, Loc, |
| DeclarationNameInfo(InvokerName, Loc), |
| InvokerFunctionTy, |
| CallOperator->getTypeSourceInfo(), |
| SC_Static, /*IsInline=*/true, |
| /*IsConstexpr=*/false, |
| CallOperator->getBody()->getLocEnd()); |
| for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) |
| InvokerParams[I]->setOwningFunction(Invoke); |
| Invoke->setParams(InvokerParams); |
| Invoke->setAccess(AS_private); |
| Invoke->setImplicit(true); |
| if (Class->isGenericLambda()) { |
| FunctionTemplateDecl *TemplateCallOperator = |
| CallOperator->getDescribedFunctionTemplate(); |
| FunctionTemplateDecl *StaticInvokerTemplate = FunctionTemplateDecl::Create( |
| S.Context, Class, Loc, InvokerName, |
| TemplateCallOperator->getTemplateParameters(), |
| Invoke); |
| StaticInvokerTemplate->setAccess(AS_private); |
| StaticInvokerTemplate->setImplicit(true); |
| Invoke->setDescribedFunctionTemplate(StaticInvokerTemplate); |
| Class->addDecl(StaticInvokerTemplate); |
| } else |
| Class->addDecl(Invoke); |
| } |
| |
| /// Add a lambda's conversion to block pointer. |
| static void addBlockPointerConversion(Sema &S, |
| SourceRange IntroducerRange, |
| CXXRecordDecl *Class, |
| CXXMethodDecl *CallOperator) { |
| QualType FunctionTy = S.getLambdaConversionFunctionResultType( |
| CallOperator->getType()->castAs<FunctionProtoType>()); |
| QualType BlockPtrTy = S.Context.getBlockPointerType(FunctionTy); |
| |
| FunctionProtoType::ExtProtoInfo ConversionEPI( |
| S.Context.getDefaultCallingConvention( |
| /*IsVariadic=*/false, /*IsCXXMethod=*/true)); |
| ConversionEPI.TypeQuals = Qualifiers::Const; |
| QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, None, ConversionEPI); |
| |
| SourceLocation Loc = IntroducerRange.getBegin(); |
| DeclarationName Name |
| = S.Context.DeclarationNames.getCXXConversionFunctionName( |
| S.Context.getCanonicalType(BlockPtrTy)); |
| DeclarationNameLoc NameLoc; |
| NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc); |
| CXXConversionDecl *Conversion |
| = CXXConversionDecl::Create(S.Context, Class, Loc, |
| DeclarationNameInfo(Name, Loc, NameLoc), |
| ConvTy, |
| S.Context.getTrivialTypeSourceInfo(ConvTy, Loc), |
| /*isInline=*/true, /*isExplicit=*/false, |
| /*isConstexpr=*/false, |
| CallOperator->getBody()->getLocEnd()); |
| Conversion->setAccess(AS_public); |
| Conversion->setImplicit(true); |
| Class->addDecl(Conversion); |
| } |
| |
| static ExprResult performLambdaVarCaptureInitialization(Sema &S, |
| const Capture &Capture, |
| FieldDecl *Field) { |
| assert(Capture.isVariableCapture() && "not a variable capture"); |
| |
| auto *Var = Capture.getVariable(); |
| SourceLocation Loc = Capture.getLocation(); |
| |
| // C++11 [expr.prim.lambda]p21: |
| // When the lambda-expression is evaluated, the entities that |
| // are captured by copy are used to direct-initialize each |
| // corresponding non-static data member of the resulting closure |
| // object. (For array members, the array elements are |
| // direct-initialized in increasing subscript order.) These |
| // initializations are performed in the (unspecified) order in |
| // which the non-static data members are declared. |
| |
| // C++ [expr.prim.lambda]p12: |
| // An entity captured by a lambda-expression is odr-used (3.2) in |
| // the scope containing the lambda-expression. |
| ExprResult RefResult = S.BuildDeclarationNameExpr( |
| CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), Loc), Var); |
| if (RefResult.isInvalid()) |
| return ExprError(); |
| Expr *Ref = RefResult.get(); |
| |
| auto Entity = InitializedEntity::InitializeLambdaCapture( |
| Var->getIdentifier(), Field->getType(), Loc); |
| InitializationKind InitKind = InitializationKind::CreateDirect(Loc, Loc, Loc); |
| InitializationSequence Init(S, Entity, InitKind, Ref); |
| return Init.Perform(S, Entity, InitKind, Ref); |
| } |
| |
| ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body, |
| Scope *CurScope) { |
| LambdaScopeInfo LSI = *cast<LambdaScopeInfo>(FunctionScopes.back()); |
| ActOnFinishFunctionBody(LSI.CallOperator, Body); |
| return BuildLambdaExpr(StartLoc, Body->getLocEnd(), &LSI); |
| } |
| |
| static LambdaCaptureDefault |
| mapImplicitCaptureStyle(CapturingScopeInfo::ImplicitCaptureStyle ICS) { |
| switch (ICS) { |
| case CapturingScopeInfo::ImpCap_None: |
| return LCD_None; |
| case CapturingScopeInfo::ImpCap_LambdaByval: |
| return LCD_ByCopy; |
| case CapturingScopeInfo::ImpCap_CapturedRegion: |
| case CapturingScopeInfo::ImpCap_LambdaByref: |
| return LCD_ByRef; |
| case CapturingScopeInfo::ImpCap_Block: |
| llvm_unreachable("block capture in lambda"); |
| } |
| llvm_unreachable("Unknown implicit capture style"); |
| } |
| |
| bool Sema::CaptureHasSideEffects(const Capture &From) { |
| if (!From.isVLATypeCapture()) { |
| Expr *Init = From.getInitExpr(); |
| if (Init && Init->HasSideEffects(Context)) |
| return true; |
| } |
| |
| if (!From.isCopyCapture()) |
| return false; |
| |
| const QualType T = From.isThisCapture() |
| ? getCurrentThisType()->getPointeeType() |
| : From.getCaptureType(); |
| |
| if (T.isVolatileQualified()) |
| return true; |
| |
| const Type *BaseT = T->getBaseElementTypeUnsafe(); |
| if (const CXXRecordDecl *RD = BaseT->getAsCXXRecordDecl()) |
| return !RD->isCompleteDefinition() || !RD->hasTrivialCopyConstructor() || |
| !RD->hasTrivialDestructor(); |
| |
| return false; |
| } |
| |
| bool Sema::DiagnoseUnusedLambdaCapture(SourceRange CaptureRange, |
| const Capture &From) { |
| if (CaptureHasSideEffects(From)) |
| return false; |
| |
| if (From.isVLATypeCapture()) |
| return false; |
| |
| auto diag = Diag(From.getLocation(), diag::warn_unused_lambda_capture); |
| if (From.isThisCapture()) |
| diag << "'this'"; |
| else |
| diag << From.getVariable(); |
| diag << From.isNonODRUsed(); |
| diag << FixItHint::CreateRemoval(CaptureRange); |
| return true; |
| } |
| |
| ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc, |
| LambdaScopeInfo *LSI) { |
| // Collect information from the lambda scope. |
| SmallVector<LambdaCapture, 4> Captures; |
| SmallVector<Expr *, 4> CaptureInits; |
| SourceLocation CaptureDefaultLoc = LSI->CaptureDefaultLoc; |
| LambdaCaptureDefault CaptureDefault = |
| mapImplicitCaptureStyle(LSI->ImpCaptureStyle); |
| CXXRecordDecl *Class; |
| CXXMethodDecl *CallOperator; |
| SourceRange IntroducerRange; |
| bool ExplicitParams; |
| bool ExplicitResultType; |
| CleanupInfo LambdaCleanup; |
| bool ContainsUnexpandedParameterPack; |
| bool IsGenericLambda; |
| { |
| CallOperator = LSI->CallOperator; |
| Class = LSI->Lambda; |
| IntroducerRange = LSI->IntroducerRange; |
| ExplicitParams = LSI->ExplicitParams; |
| ExplicitResultType = !LSI->HasImplicitReturnType; |
| LambdaCleanup = LSI->Cleanup; |
| ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack; |
| IsGenericLambda = Class->isGenericLambda(); |
| |
| CallOperator->setLexicalDeclContext(Class); |
| Decl *TemplateOrNonTemplateCallOperatorDecl = |
| CallOperator->getDescribedFunctionTemplate() |
| ? CallOperator->getDescribedFunctionTemplate() |
| : cast<Decl>(CallOperator); |
| |
| TemplateOrNonTemplateCallOperatorDecl->setLexicalDeclContext(Class); |
| Class->addDecl(TemplateOrNonTemplateCallOperatorDecl); |
| |
| PopExpressionEvaluationContext(); |
| |
| // Translate captures. |
| auto CurField = Class->field_begin(); |
| // True if the current capture has a used capture or default before it. |
| bool CurHasPreviousCapture = CaptureDefault != LCD_None; |
| SourceLocation PrevCaptureLoc = CurHasPreviousCapture ? |
| CaptureDefaultLoc : IntroducerRange.getBegin(); |
| |
| for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I, ++CurField) { |
| const Capture &From = LSI->Captures[I]; |
| |
| assert(!From.isBlockCapture() && "Cannot capture __block variables"); |
| bool IsImplicit = I >= LSI->NumExplicitCaptures; |
| |
| // Use source ranges of explicit captures for fixits where available. |
| SourceRange CaptureRange = LSI->ExplicitCaptureRanges[I]; |
| |
| // Warn about unused explicit captures. |
| bool IsCaptureUsed = true; |
| if (!CurContext->isDependentContext() && !IsImplicit && !From.isODRUsed()) { |
| // Initialized captures that are non-ODR used may not be eliminated. |
| bool NonODRUsedInitCapture = |
| IsGenericLambda && From.isNonODRUsed() && From.getInitExpr(); |
| if (!NonODRUsedInitCapture) { |
| bool IsLast = (I + 1) == LSI->NumExplicitCaptures; |
| SourceRange FixItRange; |
| if (CaptureRange.isValid()) { |
| if (!CurHasPreviousCapture && !IsLast) { |
| // If there are no captures preceding this capture, remove the |
| // following comma. |
| FixItRange = SourceRange(CaptureRange.getBegin(), |
| getLocForEndOfToken(CaptureRange.getEnd())); |
| } else { |
| // Otherwise, remove the comma since the last used capture. |
| FixItRange = SourceRange(getLocForEndOfToken(PrevCaptureLoc), |
| CaptureRange.getEnd()); |
| } |
| } |
| |
| IsCaptureUsed = !DiagnoseUnusedLambdaCapture(FixItRange, From); |
| } |
| } |
| |
| if (CaptureRange.isValid()) { |
| CurHasPreviousCapture |= IsCaptureUsed; |
| PrevCaptureLoc = CaptureRange.getEnd(); |
| } |
| |
| // Handle 'this' capture. |
| if (From.isThisCapture()) { |
| // Capturing 'this' implicitly with a default of '[=]' is deprecated, |
| // because it results in a reference capture. Don't warn prior to |
| // C++2a; there's nothing that can be done about it before then. |
| if (getLangOpts().CPlusPlus2a && IsImplicit && |
| CaptureDefault == LCD_ByCopy) { |
| Diag(From.getLocation(), diag::warn_deprecated_this_capture); |
| Diag(CaptureDefaultLoc, diag::note_deprecated_this_capture) |
| << FixItHint::CreateInsertion( |
| getLocForEndOfToken(CaptureDefaultLoc), ", this"); |
| } |
| |
| Captures.push_back( |
| LambdaCapture(From.getLocation(), IsImplicit, |
| From.isCopyCapture() ? LCK_StarThis : LCK_This)); |
| CaptureInits.push_back(From.getInitExpr()); |
| continue; |
| } |
| if (From.isVLATypeCapture()) { |
| Captures.push_back( |
| LambdaCapture(From.getLocation(), IsImplicit, LCK_VLAType)); |
| CaptureInits.push_back(nullptr); |
| continue; |
| } |
| |
| VarDecl *Var = From.getVariable(); |
| LambdaCaptureKind Kind = From.isCopyCapture() ? LCK_ByCopy : LCK_ByRef; |
| Captures.push_back(LambdaCapture(From.getLocation(), IsImplicit, Kind, |
| Var, From.getEllipsisLoc())); |
| Expr *Init = From.getInitExpr(); |
| if (!Init) { |
| auto InitResult = |
| performLambdaVarCaptureInitialization(*this, From, *CurField); |
| if (InitResult.isInvalid()) |
| return ExprError(); |
| Init = InitResult.get(); |
| } |
| CaptureInits.push_back(Init); |
| } |
| |
| // C++11 [expr.prim.lambda]p6: |
| // The closure type for a lambda-expression with no lambda-capture |
| // has a public non-virtual non-explicit const conversion function |
| // to pointer to function having the same parameter and return |
| // types as the closure type's function call operator. |
| if (Captures.empty() && CaptureDefault == LCD_None) |
| addFunctionPointerConversion(*this, IntroducerRange, Class, |
| CallOperator); |
| |
| // Objective-C++: |
| // The closure type for a lambda-expression has a public non-virtual |
| // non-explicit const conversion function to a block pointer having the |
| // same parameter and return types as the closure type's function call |
| // operator. |
| // FIXME: Fix generic lambda to block conversions. |
| if (getLangOpts().Blocks && getLangOpts().ObjC1 && !IsGenericLambda) |
| addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator); |
| |
| // Finalize the lambda class. |
| SmallVector<Decl*, 4> Fields(Class->fields()); |
| ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(), |
| SourceLocation(), ParsedAttributesView()); |
| CheckCompletedCXXClass(Class); |
| } |
| |
| Cleanup.mergeFrom(LambdaCleanup); |
| |
| LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange, |
| CaptureDefault, CaptureDefaultLoc, |
| Captures, |
| ExplicitParams, ExplicitResultType, |
| CaptureInits, EndLoc, |
| ContainsUnexpandedParameterPack); |
| // If the lambda expression's call operator is not explicitly marked constexpr |
| // and we are not in a dependent context, analyze the call operator to infer |
| // its constexpr-ness, suppressing diagnostics while doing so. |
| if (getLangOpts().CPlusPlus17 && !CallOperator->isInvalidDecl() && |
| !CallOperator->isConstexpr() && |
| !isa<CoroutineBodyStmt>(CallOperator->getBody()) && |
| !Class->getDeclContext()->isDependentContext()) { |
| TentativeAnalysisScope DiagnosticScopeGuard(*this); |
| CallOperator->setConstexpr( |
| CheckConstexprFunctionDecl(CallOperator) && |
| CheckConstexprFunctionBody(CallOperator, CallOperator->getBody())); |
| } |
| |
| // Emit delayed shadowing warnings now that the full capture list is known. |
| DiagnoseShadowingLambdaDecls(LSI); |
| |
| if (!CurContext->isDependentContext()) { |
| switch (ExprEvalContexts.back().Context) { |
| // C++11 [expr.prim.lambda]p2: |
| // A lambda-expression shall not appear in an unevaluated operand |
| // (Clause 5). |
| case ExpressionEvaluationContext::Unevaluated: |
| case ExpressionEvaluationContext::UnevaluatedList: |
| case ExpressionEvaluationContext::UnevaluatedAbstract: |
| // C++1y [expr.const]p2: |
| // A conditional-expression e is a core constant expression unless the |
| // evaluation of e, following the rules of the abstract machine, would |
| // evaluate [...] a lambda-expression. |
| // |
| // This is technically incorrect, there are some constant evaluated contexts |
| // where this should be allowed. We should probably fix this when DR1607 is |
| // ratified, it lays out the exact set of conditions where we shouldn't |
| // allow a lambda-expression. |
| case ExpressionEvaluationContext::ConstantEvaluated: |
| // We don't actually diagnose this case immediately, because we |
| // could be within a context where we might find out later that |
| // the expression is potentially evaluated (e.g., for typeid). |
| ExprEvalContexts.back().Lambdas.push_back(Lambda); |
| break; |
| |
| case ExpressionEvaluationContext::DiscardedStatement: |
| case ExpressionEvaluationContext::PotentiallyEvaluated: |
| case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed: |
| break; |
| } |
| } |
| |
| return MaybeBindToTemporary(Lambda); |
| } |
| |
| ExprResult Sema::BuildBlockForLambdaConversion(SourceLocation CurrentLocation, |
| SourceLocation ConvLocation, |
| CXXConversionDecl *Conv, |
| Expr *Src) { |
| // Make sure that the lambda call operator is marked used. |
| CXXRecordDecl *Lambda = Conv->getParent(); |
| CXXMethodDecl *CallOperator |
| = cast<CXXMethodDecl>( |
| Lambda->lookup( |
| Context.DeclarationNames.getCXXOperatorName(OO_Call)).front()); |
| CallOperator->setReferenced(); |
| CallOperator->markUsed(Context); |
| |
| ExprResult Init = PerformCopyInitialization( |
| InitializedEntity::InitializeLambdaToBlock(ConvLocation, Src->getType(), |
| /*NRVO=*/false), |
| CurrentLocation, Src); |
| if (!Init.isInvalid()) |
| Init = ActOnFinishFullExpr(Init.get()); |
| |
| if (Init.isInvalid()) |
| return ExprError(); |
| |
| // Create the new block to be returned. |
| BlockDecl *Block = BlockDecl::Create(Context, CurContext, ConvLocation); |
| |
| // Set the type information. |
| Block->setSignatureAsWritten(CallOperator->getTypeSourceInfo()); |
| Block->setIsVariadic(CallOperator->isVariadic()); |
| Block->setBlockMissingReturnType(false); |
| |
| // Add parameters. |
| SmallVector<ParmVarDecl *, 4> BlockParams; |
| for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) { |
| ParmVarDecl *From = CallOperator->getParamDecl(I); |
| BlockParams.push_back(ParmVarDecl::Create(Context, Block, |
| From->getLocStart(), |
| From->getLocation(), |
| From->getIdentifier(), |
| From->getType(), |
| From->getTypeSourceInfo(), |
| From->getStorageClass(), |
| /*DefaultArg=*/nullptr)); |
| } |
| Block->setParams(BlockParams); |
| |
| Block->setIsConversionFromLambda(true); |
| |
| // Add capture. The capture uses a fake variable, which doesn't correspond |
| // to any actual memory location. However, the initializer copy-initializes |
| // the lambda object. |
| TypeSourceInfo *CapVarTSI = |
| Context.getTrivialTypeSourceInfo(Src->getType()); |
| VarDecl *CapVar = VarDecl::Create(Context, Block, ConvLocation, |
| ConvLocation, nullptr, |
| Src->getType(), CapVarTSI, |
| SC_None); |
| BlockDecl::Capture Capture(/*Variable=*/CapVar, /*ByRef=*/false, |
| /*Nested=*/false, /*Copy=*/Init.get()); |
| Block->setCaptures(Context, Capture, /*CapturesCXXThis=*/false); |
| |
| // Add a fake function body to the block. IR generation is responsible |
| // for filling in the actual body, which cannot be expressed as an AST. |
| Block->setBody(new (Context) CompoundStmt(ConvLocation)); |
| |
| // Create the block literal expression. |
| Expr *BuildBlock = new (Context) BlockExpr(Block, Conv->getConversionType()); |
| ExprCleanupObjects.push_back(Block); |
| Cleanup.setExprNeedsCleanups(true); |
| |
| return BuildBlock; |
| } |
