1 //===--- SemaLambda.cpp - Semantic Analysis for C++11 Lambdas -------------===//
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 C++ lambda expressions.
12 //===----------------------------------------------------------------------===//
13 #include "clang/Sema/DeclSpec.h"
14 #include "TypeLocBuilder.h"
15 #include "clang/AST/ASTLambda.h"
16 #include "clang/AST/ExprCXX.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Sema/Initialization.h"
19 #include "clang/Sema/Lookup.h"
20 #include "clang/Sema/Scope.h"
21 #include "clang/Sema/ScopeInfo.h"
22 #include "clang/Sema/SemaInternal.h"
23 #include "clang/Sema/SemaLambda.h"
24 using namespace clang;
27 /// Examines the FunctionScopeInfo stack to determine the nearest
28 /// enclosing lambda (to the current lambda) that is 'capture-ready' for
29 /// the variable referenced in the current lambda (i.e. \p VarToCapture).
30 /// If successful, returns the index into Sema's FunctionScopeInfo stack
31 /// of the capture-ready lambda's LambdaScopeInfo.
33 /// Climbs down the stack of lambdas (deepest nested lambda - i.e. current
34 /// lambda - is on top) to determine the index of the nearest enclosing/outer
35 /// lambda that is ready to capture the \p VarToCapture being referenced in
36 /// the current lambda.
37 /// As we climb down the stack, we want the index of the first such lambda -
38 /// that is the lambda with the highest index that is 'capture-ready'.
40 /// A lambda 'L' is capture-ready for 'V' (var or this) if:
41 /// - its enclosing context is non-dependent
42 /// - and if the chain of lambdas between L and the lambda in which
43 /// V is potentially used (i.e. the lambda at the top of the scope info
44 /// stack), can all capture or have already captured V.
45 /// If \p VarToCapture is 'null' then we are trying to capture 'this'.
47 /// Note that a lambda that is deemed 'capture-ready' still needs to be checked
48 /// for whether it is 'capture-capable' (see
49 /// getStackIndexOfNearestEnclosingCaptureCapableLambda), before it can truly
52 /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a
53 /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda
54 /// is at the top of the stack and has the highest index.
55 /// \param VarToCapture - the variable to capture. If NULL, capture 'this'.
57 /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains
58 /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda
59 /// which is capture-ready. If the return value evaluates to 'false' then
60 /// no lambda is capture-ready for \p VarToCapture.
62 static inline Optional<unsigned>
63 getStackIndexOfNearestEnclosingCaptureReadyLambda(
64 ArrayRef<const clang::sema::FunctionScopeInfo *> FunctionScopes,
65 VarDecl *VarToCapture) {
66 // Label failure to capture.
67 const Optional<unsigned> NoLambdaIsCaptureReady;
69 // Ignore all inner captured regions.
70 unsigned CurScopeIndex = FunctionScopes.size() - 1;
71 while (CurScopeIndex > 0 && isa<clang::sema::CapturedRegionScopeInfo>(
72 FunctionScopes[CurScopeIndex]))
75 isa<clang::sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]) &&
76 "The function on the top of sema's function-info stack must be a lambda");
78 // If VarToCapture is null, we are attempting to capture 'this'.
79 const bool IsCapturingThis = !VarToCapture;
80 const bool IsCapturingVariable = !IsCapturingThis;
82 // Start with the current lambda at the top of the stack (highest index).
83 DeclContext *EnclosingDC =
84 cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex])->CallOperator;
87 const clang::sema::LambdaScopeInfo *LSI =
88 cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]);
89 // IF we have climbed down to an intervening enclosing lambda that contains
90 // the variable declaration - it obviously can/must not capture the
92 // Since its enclosing DC is dependent, all the lambdas between it and the
93 // innermost nested lambda are dependent (otherwise we wouldn't have
94 // arrived here) - so we don't yet have a lambda that can capture the
96 if (IsCapturingVariable &&
97 VarToCapture->getDeclContext()->Equals(EnclosingDC))
98 return NoLambdaIsCaptureReady;
100 // For an enclosing lambda to be capture ready for an entity, all
101 // intervening lambda's have to be able to capture that entity. If even
102 // one of the intervening lambda's is not capable of capturing the entity
103 // then no enclosing lambda can ever capture that entity.
107 // [](auto b) { #2 <-- an intervening lambda that can never capture 'x'
109 // f(x, c); <-- can not lead to x's speculative capture by #1 or #2
111 // If they do not have a default implicit capture, check to see
112 // if the entity has already been explicitly captured.
113 // If even a single dependent enclosing lambda lacks the capability
114 // to ever capture this variable, there is no further enclosing
115 // non-dependent lambda that can capture this variable.
116 if (LSI->ImpCaptureStyle == sema::LambdaScopeInfo::ImpCap_None) {
117 if (IsCapturingVariable && !LSI->isCaptured(VarToCapture))
118 return NoLambdaIsCaptureReady;
119 if (IsCapturingThis && !LSI->isCXXThisCaptured())
120 return NoLambdaIsCaptureReady;
122 EnclosingDC = getLambdaAwareParentOfDeclContext(EnclosingDC);
124 assert(CurScopeIndex);
126 } while (!EnclosingDC->isTranslationUnit() &&
127 EnclosingDC->isDependentContext() &&
128 isLambdaCallOperator(EnclosingDC));
130 assert(CurScopeIndex < (FunctionScopes.size() - 1));
131 // If the enclosingDC is not dependent, then the immediately nested lambda
132 // (one index above) is capture-ready.
133 if (!EnclosingDC->isDependentContext())
134 return CurScopeIndex + 1;
135 return NoLambdaIsCaptureReady;
138 /// Examines the FunctionScopeInfo stack to determine the nearest
139 /// enclosing lambda (to the current lambda) that is 'capture-capable' for
140 /// the variable referenced in the current lambda (i.e. \p VarToCapture).
141 /// If successful, returns the index into Sema's FunctionScopeInfo stack
142 /// of the capture-capable lambda's LambdaScopeInfo.
144 /// Given the current stack of lambdas being processed by Sema and
145 /// the variable of interest, to identify the nearest enclosing lambda (to the
146 /// current lambda at the top of the stack) that can truly capture
147 /// a variable, it has to have the following two properties:
148 /// a) 'capture-ready' - be the innermost lambda that is 'capture-ready':
149 /// - climb down the stack (i.e. starting from the innermost and examining
150 /// each outer lambda step by step) checking if each enclosing
151 /// lambda can either implicitly or explicitly capture the variable.
152 /// Record the first such lambda that is enclosed in a non-dependent
153 /// context. If no such lambda currently exists return failure.
154 /// b) 'capture-capable' - make sure the 'capture-ready' lambda can truly
155 /// capture the variable by checking all its enclosing lambdas:
156 /// - check if all outer lambdas enclosing the 'capture-ready' lambda
157 /// identified above in 'a' can also capture the variable (this is done
158 /// via tryCaptureVariable for variables and CheckCXXThisCapture for
159 /// 'this' by passing in the index of the Lambda identified in step 'a')
161 /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a
162 /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda
163 /// is at the top of the stack.
165 /// \param VarToCapture - the variable to capture. If NULL, capture 'this'.
168 /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains
169 /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda
170 /// which is capture-capable. If the return value evaluates to 'false' then
171 /// no lambda is capture-capable for \p VarToCapture.
173 Optional<unsigned> clang::getStackIndexOfNearestEnclosingCaptureCapableLambda(
174 ArrayRef<const sema::FunctionScopeInfo *> FunctionScopes,
175 VarDecl *VarToCapture, Sema &S) {
177 const Optional<unsigned> NoLambdaIsCaptureCapable;
179 const Optional<unsigned> OptionalStackIndex =
180 getStackIndexOfNearestEnclosingCaptureReadyLambda(FunctionScopes,
182 if (!OptionalStackIndex)
183 return NoLambdaIsCaptureCapable;
185 const unsigned IndexOfCaptureReadyLambda = OptionalStackIndex.getValue();
186 assert(((IndexOfCaptureReadyLambda != (FunctionScopes.size() - 1)) ||
187 S.getCurGenericLambda()) &&
188 "The capture ready lambda for a potential capture can only be the "
189 "current lambda if it is a generic lambda");
191 const sema::LambdaScopeInfo *const CaptureReadyLambdaLSI =
192 cast<sema::LambdaScopeInfo>(FunctionScopes[IndexOfCaptureReadyLambda]);
194 // If VarToCapture is null, we are attempting to capture 'this'
195 const bool IsCapturingThis = !VarToCapture;
196 const bool IsCapturingVariable = !IsCapturingThis;
198 if (IsCapturingVariable) {
199 // Check if the capture-ready lambda can truly capture the variable, by
200 // checking whether all enclosing lambdas of the capture-ready lambda allow
201 // the capture - i.e. make sure it is capture-capable.
202 QualType CaptureType, DeclRefType;
203 const bool CanCaptureVariable =
204 !S.tryCaptureVariable(VarToCapture,
205 /*ExprVarIsUsedInLoc*/ SourceLocation(),
206 clang::Sema::TryCapture_Implicit,
207 /*EllipsisLoc*/ SourceLocation(),
208 /*BuildAndDiagnose*/ false, CaptureType,
209 DeclRefType, &IndexOfCaptureReadyLambda);
210 if (!CanCaptureVariable)
211 return NoLambdaIsCaptureCapable;
213 // Check if the capture-ready lambda can truly capture 'this' by checking
214 // whether all enclosing lambdas of the capture-ready lambda can capture
216 const bool CanCaptureThis =
217 !S.CheckCXXThisCapture(
218 CaptureReadyLambdaLSI->PotentialThisCaptureLocation,
219 /*Explicit*/ false, /*BuildAndDiagnose*/ false,
220 &IndexOfCaptureReadyLambda);
222 return NoLambdaIsCaptureCapable;
224 return IndexOfCaptureReadyLambda;
227 static inline TemplateParameterList *
228 getGenericLambdaTemplateParameterList(LambdaScopeInfo *LSI, Sema &SemaRef) {
229 if (LSI->GLTemplateParameterList)
230 return LSI->GLTemplateParameterList;
232 if (!LSI->AutoTemplateParams.empty()) {
233 SourceRange IntroRange = LSI->IntroducerRange;
234 SourceLocation LAngleLoc = IntroRange.getBegin();
235 SourceLocation RAngleLoc = IntroRange.getEnd();
236 LSI->GLTemplateParameterList = TemplateParameterList::Create(
238 /*Template kw loc*/ SourceLocation(), LAngleLoc,
239 llvm::makeArrayRef((NamedDecl *const *)LSI->AutoTemplateParams.data(),
240 LSI->AutoTemplateParams.size()),
243 return LSI->GLTemplateParameterList;
246 CXXRecordDecl *Sema::createLambdaClosureType(SourceRange IntroducerRange,
247 TypeSourceInfo *Info,
249 LambdaCaptureDefault CaptureDefault) {
250 DeclContext *DC = CurContext;
251 while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
252 DC = DC->getParent();
253 bool IsGenericLambda = getGenericLambdaTemplateParameterList(getCurLambda(),
255 // Start constructing the lambda class.
256 CXXRecordDecl *Class = CXXRecordDecl::CreateLambda(Context, DC, Info,
257 IntroducerRange.getBegin(),
266 /// Determine whether the given context is or is enclosed in an inline
268 static bool isInInlineFunction(const DeclContext *DC) {
269 while (!DC->isFileContext()) {
270 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DC))
274 DC = DC->getLexicalParent();
280 MangleNumberingContext *
281 Sema::getCurrentMangleNumberContext(const DeclContext *DC,
282 Decl *&ManglingContextDecl) {
283 // Compute the context for allocating mangling numbers in the current
284 // expression, if the ABI requires them.
285 ManglingContextDecl = ExprEvalContexts.back().ManglingContextDecl;
296 // Default arguments of member function parameters that appear in a class
297 // definition, as well as the initializers of data members, receive special
298 // treatment. Identify them.
299 if (ManglingContextDecl) {
300 if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(ManglingContextDecl)) {
301 if (const DeclContext *LexicalDC
302 = Param->getDeclContext()->getLexicalParent())
303 if (LexicalDC->isRecord())
304 Kind = DefaultArgument;
305 } else if (VarDecl *Var = dyn_cast<VarDecl>(ManglingContextDecl)) {
306 if (Var->getDeclContext()->isRecord())
307 Kind = StaticDataMember;
308 else if (Var->getMostRecentDecl()->isInline())
309 Kind = InlineVariable;
310 else if (Var->getDescribedVarTemplate())
311 Kind = VariableTemplate;
312 else if (auto *VTS = dyn_cast<VarTemplateSpecializationDecl>(Var)) {
313 if (!VTS->isExplicitSpecialization())
314 Kind = VariableTemplate;
316 } else if (isa<FieldDecl>(ManglingContextDecl)) {
321 // Itanium ABI [5.1.7]:
322 // In the following contexts [...] the one-definition rule requires closure
323 // types in different translation units to "correspond":
324 bool IsInNonspecializedTemplate =
325 inTemplateInstantiation() || CurContext->isDependentContext();
328 // -- the bodies of non-exported nonspecialized template functions
329 // -- the bodies of inline functions
330 if ((IsInNonspecializedTemplate &&
331 !(ManglingContextDecl && isa<ParmVarDecl>(ManglingContextDecl))) ||
332 isInInlineFunction(CurContext)) {
333 ManglingContextDecl = nullptr;
334 while (auto *CD = dyn_cast<CapturedDecl>(DC))
335 DC = CD->getParent();
336 return &Context.getManglingNumberContext(DC);
339 ManglingContextDecl = nullptr;
343 case StaticDataMember:
344 // -- the initializers of nonspecialized static members of template classes
345 if (!IsInNonspecializedTemplate) {
346 ManglingContextDecl = nullptr;
349 // Fall through to get the current context.
353 // -- the in-class initializers of class members
354 case DefaultArgument:
355 // -- default arguments appearing in class definitions
357 // -- the initializers of inline variables
358 case VariableTemplate:
359 // -- the initializers of templated variables
360 return &ExprEvalContexts.back().getMangleNumberingContext(Context);
363 llvm_unreachable("unexpected context");
366 MangleNumberingContext &
367 Sema::ExpressionEvaluationContextRecord::getMangleNumberingContext(
369 assert(ManglingContextDecl && "Need to have a context declaration");
370 if (!MangleNumbering)
371 MangleNumbering = Ctx.createMangleNumberingContext();
372 return *MangleNumbering;
375 CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
376 SourceRange IntroducerRange,
377 TypeSourceInfo *MethodTypeInfo,
378 SourceLocation EndLoc,
379 ArrayRef<ParmVarDecl *> Params,
380 const bool IsConstexprSpecified) {
381 QualType MethodType = MethodTypeInfo->getType();
382 TemplateParameterList *TemplateParams =
383 getGenericLambdaTemplateParameterList(getCurLambda(), *this);
384 // If a lambda appears in a dependent context or is a generic lambda (has
385 // template parameters) and has an 'auto' return type, deduce it to a
387 if (Class->isDependentContext() || TemplateParams) {
388 const FunctionProtoType *FPT = MethodType->castAs<FunctionProtoType>();
389 QualType Result = FPT->getReturnType();
390 if (Result->isUndeducedType()) {
391 Result = SubstAutoType(Result, Context.DependentTy);
392 MethodType = Context.getFunctionType(Result, FPT->getParamTypes(),
393 FPT->getExtProtoInfo());
397 // C++11 [expr.prim.lambda]p5:
398 // The closure type for a lambda-expression has a public inline function
399 // call operator (13.5.4) whose parameters and return type are described by
400 // the lambda-expression's parameter-declaration-clause and
401 // trailing-return-type respectively.
402 DeclarationName MethodName
403 = Context.DeclarationNames.getCXXOperatorName(OO_Call);
404 DeclarationNameLoc MethodNameLoc;
405 MethodNameLoc.CXXOperatorName.BeginOpNameLoc
406 = IntroducerRange.getBegin().getRawEncoding();
407 MethodNameLoc.CXXOperatorName.EndOpNameLoc
408 = IntroducerRange.getEnd().getRawEncoding();
409 CXXMethodDecl *Method
410 = CXXMethodDecl::Create(Context, Class, EndLoc,
411 DeclarationNameInfo(MethodName,
412 IntroducerRange.getBegin(),
414 MethodType, MethodTypeInfo,
417 IsConstexprSpecified,
419 Method->setAccess(AS_public);
421 // Temporarily set the lexical declaration context to the current
422 // context, so that the Scope stack matches the lexical nesting.
423 Method->setLexicalDeclContext(CurContext);
424 // Create a function template if we have a template parameter list
425 FunctionTemplateDecl *const TemplateMethod = TemplateParams ?
426 FunctionTemplateDecl::Create(Context, Class,
427 Method->getLocation(), MethodName,
430 if (TemplateMethod) {
431 TemplateMethod->setLexicalDeclContext(CurContext);
432 TemplateMethod->setAccess(AS_public);
433 Method->setDescribedFunctionTemplate(TemplateMethod);
437 if (!Params.empty()) {
438 Method->setParams(Params);
439 CheckParmsForFunctionDef(Params,
440 /*CheckParameterNames=*/false);
442 for (auto P : Method->parameters())
443 P->setOwningFunction(Method);
446 Decl *ManglingContextDecl;
447 if (MangleNumberingContext *MCtx =
448 getCurrentMangleNumberContext(Class->getDeclContext(),
449 ManglingContextDecl)) {
450 unsigned ManglingNumber = MCtx->getManglingNumber(Method);
451 Class->setLambdaMangling(ManglingNumber, ManglingContextDecl);
457 void Sema::buildLambdaScope(LambdaScopeInfo *LSI,
458 CXXMethodDecl *CallOperator,
459 SourceRange IntroducerRange,
460 LambdaCaptureDefault CaptureDefault,
461 SourceLocation CaptureDefaultLoc,
463 bool ExplicitResultType,
465 LSI->CallOperator = CallOperator;
466 CXXRecordDecl *LambdaClass = CallOperator->getParent();
467 LSI->Lambda = LambdaClass;
468 if (CaptureDefault == LCD_ByCopy)
469 LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByval;
470 else if (CaptureDefault == LCD_ByRef)
471 LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByref;
472 LSI->CaptureDefaultLoc = CaptureDefaultLoc;
473 LSI->IntroducerRange = IntroducerRange;
474 LSI->ExplicitParams = ExplicitParams;
475 LSI->Mutable = Mutable;
477 if (ExplicitResultType) {
478 LSI->ReturnType = CallOperator->getReturnType();
480 if (!LSI->ReturnType->isDependentType() &&
481 !LSI->ReturnType->isVoidType()) {
482 if (RequireCompleteType(CallOperator->getLocStart(), LSI->ReturnType,
483 diag::err_lambda_incomplete_result)) {
488 LSI->HasImplicitReturnType = true;
492 void Sema::finishLambdaExplicitCaptures(LambdaScopeInfo *LSI) {
493 LSI->finishedExplicitCaptures();
496 void Sema::addLambdaParameters(CXXMethodDecl *CallOperator, Scope *CurScope) {
497 // Introduce our parameters into the function scope
498 for (unsigned p = 0, NumParams = CallOperator->getNumParams();
499 p < NumParams; ++p) {
500 ParmVarDecl *Param = CallOperator->getParamDecl(p);
502 // If this has an identifier, add it to the scope stack.
503 if (CurScope && Param->getIdentifier()) {
504 CheckShadow(CurScope, Param);
506 PushOnScopeChains(Param, CurScope);
511 /// If this expression is an enumerator-like expression of some type
512 /// T, return the type T; otherwise, return null.
514 /// Pointer comparisons on the result here should always work because
515 /// it's derived from either the parent of an EnumConstantDecl
516 /// (i.e. the definition) or the declaration returned by
517 /// EnumType::getDecl() (i.e. the definition).
518 static EnumDecl *findEnumForBlockReturn(Expr *E) {
519 // An expression is an enumerator-like expression of type T if,
520 // ignoring parens and parens-like expressions:
521 E = E->IgnoreParens();
523 // - it is an enumerator whose enum type is T or
524 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
525 if (EnumConstantDecl *D
526 = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
527 return cast<EnumDecl>(D->getDeclContext());
532 // - it is a comma expression whose RHS is an enumerator-like
533 // expression of type T or
534 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
535 if (BO->getOpcode() == BO_Comma)
536 return findEnumForBlockReturn(BO->getRHS());
540 // - it is a statement-expression whose value expression is an
541 // enumerator-like expression of type T or
542 if (StmtExpr *SE = dyn_cast<StmtExpr>(E)) {
543 if (Expr *last = dyn_cast_or_null<Expr>(SE->getSubStmt()->body_back()))
544 return findEnumForBlockReturn(last);
548 // - it is a ternary conditional operator (not the GNU ?:
549 // extension) whose second and third operands are
550 // enumerator-like expressions of type T or
551 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
552 if (EnumDecl *ED = findEnumForBlockReturn(CO->getTrueExpr()))
553 if (ED == findEnumForBlockReturn(CO->getFalseExpr()))
559 // - it is an implicit integral conversion applied to an
560 // enumerator-like expression of type T or
561 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
562 // We can sometimes see integral conversions in valid
563 // enumerator-like expressions.
564 if (ICE->getCastKind() == CK_IntegralCast)
565 return findEnumForBlockReturn(ICE->getSubExpr());
567 // Otherwise, just rely on the type.
570 // - it is an expression of that formal enum type.
571 if (const EnumType *ET = E->getType()->getAs<EnumType>()) {
572 return ET->getDecl();
579 /// Attempt to find a type T for which the returned expression of the
580 /// given statement is an enumerator-like expression of that type.
581 static EnumDecl *findEnumForBlockReturn(ReturnStmt *ret) {
582 if (Expr *retValue = ret->getRetValue())
583 return findEnumForBlockReturn(retValue);
587 /// Attempt to find a common type T for which all of the returned
588 /// expressions in a block are enumerator-like expressions of that
590 static EnumDecl *findCommonEnumForBlockReturns(ArrayRef<ReturnStmt*> returns) {
591 ArrayRef<ReturnStmt*>::iterator i = returns.begin(), e = returns.end();
593 // Try to find one for the first return.
594 EnumDecl *ED = findEnumForBlockReturn(*i);
595 if (!ED) return nullptr;
597 // Check that the rest of the returns have the same enum.
598 for (++i; i != e; ++i) {
599 if (findEnumForBlockReturn(*i) != ED)
603 // Never infer an anonymous enum type.
604 if (!ED->hasNameForLinkage()) return nullptr;
609 /// Adjust the given return statements so that they formally return
610 /// the given type. It should require, at most, an IntegralCast.
611 static void adjustBlockReturnsToEnum(Sema &S, ArrayRef<ReturnStmt*> returns,
612 QualType returnType) {
613 for (ArrayRef<ReturnStmt*>::iterator
614 i = returns.begin(), e = returns.end(); i != e; ++i) {
615 ReturnStmt *ret = *i;
616 Expr *retValue = ret->getRetValue();
617 if (S.Context.hasSameType(retValue->getType(), returnType))
620 // Right now we only support integral fixup casts.
621 assert(returnType->isIntegralOrUnscopedEnumerationType());
622 assert(retValue->getType()->isIntegralOrUnscopedEnumerationType());
624 ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(retValue);
626 Expr *E = (cleanups ? cleanups->getSubExpr() : retValue);
627 E = ImplicitCastExpr::Create(S.Context, returnType, CK_IntegralCast,
628 E, /*base path*/ nullptr, VK_RValue);
630 cleanups->setSubExpr(E);
637 void Sema::deduceClosureReturnType(CapturingScopeInfo &CSI) {
638 assert(CSI.HasImplicitReturnType);
639 // If it was ever a placeholder, it had to been deduced to DependentTy.
640 assert(CSI.ReturnType.isNull() || !CSI.ReturnType->isUndeducedType());
641 assert((!isa<LambdaScopeInfo>(CSI) || !getLangOpts().CPlusPlus14) &&
642 "lambda expressions use auto deduction in C++14 onwards");
644 // C++ core issue 975:
645 // If a lambda-expression does not include a trailing-return-type,
646 // it is as if the trailing-return-type denotes the following type:
647 // - if there are no return statements in the compound-statement,
648 // or all return statements return either an expression of type
649 // void or no expression or braced-init-list, the type void;
650 // - otherwise, if all return statements return an expression
651 // and the types of the returned expressions after
652 // lvalue-to-rvalue conversion (4.1 [conv.lval]),
653 // array-to-pointer conversion (4.2 [conv.array]), and
654 // function-to-pointer conversion (4.3 [conv.func]) are the
655 // same, that common type;
656 // - otherwise, the program is ill-formed.
658 // C++ core issue 1048 additionally removes top-level cv-qualifiers
659 // from the types of returned expressions to match the C++14 auto
662 // In addition, in blocks in non-C++ modes, if all of the return
663 // statements are enumerator-like expressions of some type T, where
664 // T has a name for linkage, then we infer the return type of the
665 // block to be that type.
667 // First case: no return statements, implicit void return type.
668 ASTContext &Ctx = getASTContext();
669 if (CSI.Returns.empty()) {
670 // It's possible there were simply no /valid/ return statements.
671 // In this case, the first one we found may have at least given us a type.
672 if (CSI.ReturnType.isNull())
673 CSI.ReturnType = Ctx.VoidTy;
677 // Second case: at least one return statement has dependent type.
678 // Delay type checking until instantiation.
679 assert(!CSI.ReturnType.isNull() && "We should have a tentative return type.");
680 if (CSI.ReturnType->isDependentType())
683 // Try to apply the enum-fuzz rule.
684 if (!getLangOpts().CPlusPlus) {
685 assert(isa<BlockScopeInfo>(CSI));
686 const EnumDecl *ED = findCommonEnumForBlockReturns(CSI.Returns);
688 CSI.ReturnType = Context.getTypeDeclType(ED);
689 adjustBlockReturnsToEnum(*this, CSI.Returns, CSI.ReturnType);
694 // Third case: only one return statement. Don't bother doing extra work!
695 if (CSI.Returns.size() == 1)
698 // General case: many return statements.
699 // Check that they all have compatible return types.
701 // We require the return types to strictly match here.
702 // Note that we've already done the required promotions as part of
703 // processing the return statement.
704 for (const ReturnStmt *RS : CSI.Returns) {
705 const Expr *RetE = RS->getRetValue();
707 QualType ReturnType =
708 (RetE ? RetE->getType() : Context.VoidTy).getUnqualifiedType();
709 if (Context.getCanonicalFunctionResultType(ReturnType) ==
710 Context.getCanonicalFunctionResultType(CSI.ReturnType)) {
711 // Use the return type with the strictest possible nullability annotation.
712 auto RetTyNullability = ReturnType->getNullability(Ctx);
713 auto BlockNullability = CSI.ReturnType->getNullability(Ctx);
714 if (BlockNullability &&
715 (!RetTyNullability ||
716 hasWeakerNullability(*RetTyNullability, *BlockNullability)))
717 CSI.ReturnType = ReturnType;
721 // FIXME: This is a poor diagnostic for ReturnStmts without expressions.
722 // TODO: It's possible that the *first* return is the divergent one.
723 Diag(RS->getLocStart(),
724 diag::err_typecheck_missing_return_type_incompatible)
725 << ReturnType << CSI.ReturnType
726 << isa<LambdaScopeInfo>(CSI);
727 // Continue iterating so that we keep emitting diagnostics.
731 QualType Sema::buildLambdaInitCaptureInitialization(SourceLocation Loc,
736 // Create an 'auto' or 'auto&' TypeSourceInfo that we can use to
738 QualType DeductType = Context.getAutoDeductType();
740 TLB.pushTypeSpec(DeductType).setNameLoc(Loc);
742 DeductType = BuildReferenceType(DeductType, true, Loc, Id);
743 assert(!DeductType.isNull() && "can't build reference to auto");
744 TLB.push<ReferenceTypeLoc>(DeductType).setSigilLoc(Loc);
746 TypeSourceInfo *TSI = TLB.getTypeSourceInfo(Context, DeductType);
748 // Deduce the type of the init capture.
749 QualType DeducedType = deduceVarTypeFromInitializer(
750 /*VarDecl*/nullptr, DeclarationName(Id), DeductType, TSI,
751 SourceRange(Loc, Loc), IsDirectInit, Init);
752 if (DeducedType.isNull())
755 // Are we a non-list direct initialization?
756 ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
758 // Perform initialization analysis and ensure any implicit conversions
759 // (such as lvalue-to-rvalue) are enforced.
760 InitializedEntity Entity =
761 InitializedEntity::InitializeLambdaCapture(Id, DeducedType, Loc);
762 InitializationKind Kind =
764 ? (CXXDirectInit ? InitializationKind::CreateDirect(
765 Loc, Init->getLocStart(), Init->getLocEnd())
766 : InitializationKind::CreateDirectList(Loc))
767 : InitializationKind::CreateCopy(Loc, Init->getLocStart());
769 MultiExprArg Args = Init;
772 MultiExprArg(CXXDirectInit->getExprs(), CXXDirectInit->getNumExprs());
774 InitializationSequence InitSeq(*this, Entity, Kind, Args);
775 ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
777 if (Result.isInvalid())
779 Init = Result.getAs<Expr>();
781 // The init-capture initialization is a full-expression that must be
782 // processed as one before we enter the declcontext of the lambda's
784 Result = ActOnFinishFullExpr(Init, Loc, /*DiscardedValue*/ false,
785 /*IsConstexpr*/ false,
786 /*IsLambdaInitCaptureInitializer*/ true);
787 if (Result.isInvalid())
790 Init = Result.getAs<Expr>();
794 VarDecl *Sema::createLambdaInitCaptureVarDecl(SourceLocation Loc,
795 QualType InitCaptureType,
797 unsigned InitStyle, Expr *Init) {
798 TypeSourceInfo *TSI = Context.getTrivialTypeSourceInfo(InitCaptureType,
800 // Create a dummy variable representing the init-capture. This is not actually
801 // used as a variable, and only exists as a way to name and refer to the
803 // FIXME: Pass in separate source locations for '&' and identifier.
804 VarDecl *NewVD = VarDecl::Create(Context, CurContext, Loc,
805 Loc, Id, InitCaptureType, TSI, SC_Auto);
806 NewVD->setInitCapture(true);
807 NewVD->setReferenced(true);
808 // FIXME: Pass in a VarDecl::InitializationStyle.
809 NewVD->setInitStyle(static_cast<VarDecl::InitializationStyle>(InitStyle));
810 NewVD->markUsed(Context);
811 NewVD->setInit(Init);
815 FieldDecl *Sema::buildInitCaptureField(LambdaScopeInfo *LSI, VarDecl *Var) {
816 FieldDecl *Field = FieldDecl::Create(
817 Context, LSI->Lambda, Var->getLocation(), Var->getLocation(),
818 nullptr, Var->getType(), Var->getTypeSourceInfo(), nullptr, false,
820 Field->setImplicit(true);
821 Field->setAccess(AS_private);
822 LSI->Lambda->addDecl(Field);
824 LSI->addCapture(Var, /*isBlock*/false, Var->getType()->isReferenceType(),
825 /*isNested*/false, Var->getLocation(), SourceLocation(),
826 Var->getType(), Var->getInit());
830 void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
831 Declarator &ParamInfo,
833 // Determine if we're within a context where we know that the lambda will
834 // be dependent, because there are template parameters in scope.
835 bool KnownDependent = false;
836 LambdaScopeInfo *const LSI = getCurLambda();
837 assert(LSI && "LambdaScopeInfo should be on stack!");
839 // The lambda-expression's closure type might be dependent even if its
840 // semantic context isn't, if it appears within a default argument of a
841 // function template.
842 if (CurScope->getTemplateParamParent())
843 KnownDependent = true;
845 // Determine the signature of the call operator.
846 TypeSourceInfo *MethodTyInfo;
847 bool ExplicitParams = true;
848 bool ExplicitResultType = true;
849 bool ContainsUnexpandedParameterPack = false;
850 SourceLocation EndLoc;
851 SmallVector<ParmVarDecl *, 8> Params;
852 if (ParamInfo.getNumTypeObjects() == 0) {
853 // C++11 [expr.prim.lambda]p4:
854 // If a lambda-expression does not include a lambda-declarator, it is as
855 // if the lambda-declarator were ().
856 FunctionProtoType::ExtProtoInfo EPI(Context.getDefaultCallingConvention(
857 /*IsVariadic=*/false, /*IsCXXMethod=*/true));
858 EPI.HasTrailingReturn = true;
859 EPI.TypeQuals |= DeclSpec::TQ_const;
860 // C++1y [expr.prim.lambda]:
861 // The lambda return type is 'auto', which is replaced by the
862 // trailing-return type if provided and/or deduced from 'return'
864 // We don't do this before C++1y, because we don't support deduced return
866 QualType DefaultTypeForNoTrailingReturn =
867 getLangOpts().CPlusPlus14 ? Context.getAutoDeductType()
868 : Context.DependentTy;
870 Context.getFunctionType(DefaultTypeForNoTrailingReturn, None, EPI);
871 MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
872 ExplicitParams = false;
873 ExplicitResultType = false;
874 EndLoc = Intro.Range.getEnd();
876 assert(ParamInfo.isFunctionDeclarator() &&
877 "lambda-declarator is a function");
878 DeclaratorChunk::FunctionTypeInfo &FTI = ParamInfo.getFunctionTypeInfo();
880 // C++11 [expr.prim.lambda]p5:
881 // This function call operator is declared const (9.3.1) if and only if
882 // the lambda-expression's parameter-declaration-clause is not followed
883 // by mutable. It is neither virtual nor declared volatile. [...]
884 if (!FTI.hasMutableQualifier())
885 FTI.TypeQuals |= DeclSpec::TQ_const;
887 MethodTyInfo = GetTypeForDeclarator(ParamInfo, CurScope);
888 assert(MethodTyInfo && "no type from lambda-declarator");
889 EndLoc = ParamInfo.getSourceRange().getEnd();
891 ExplicitResultType = FTI.hasTrailingReturnType();
893 if (FTIHasNonVoidParameters(FTI)) {
894 Params.reserve(FTI.NumParams);
895 for (unsigned i = 0, e = FTI.NumParams; i != e; ++i)
896 Params.push_back(cast<ParmVarDecl>(FTI.Params[i].Param));
899 // Check for unexpanded parameter packs in the method type.
900 if (MethodTyInfo->getType()->containsUnexpandedParameterPack())
901 ContainsUnexpandedParameterPack = true;
904 CXXRecordDecl *Class = createLambdaClosureType(Intro.Range, MethodTyInfo,
905 KnownDependent, Intro.Default);
907 CXXMethodDecl *Method =
908 startLambdaDefinition(Class, Intro.Range, MethodTyInfo, EndLoc, Params,
909 ParamInfo.getDeclSpec().isConstexprSpecified());
911 CheckCXXDefaultArguments(Method);
913 // This represents the function body for the lambda function, check if we
914 // have to apply optnone due to a pragma.
915 AddRangeBasedOptnone(Method);
917 // code_seg attribute on lambda apply to the method.
918 if (Attr *A = getImplicitCodeSegOrSectionAttrForFunction(Method, /*IsDefinition=*/true))
921 // Attributes on the lambda apply to the method.
922 ProcessDeclAttributes(CurScope, Method, ParamInfo);
924 // CUDA lambdas get implicit attributes based on the scope in which they're
926 if (getLangOpts().CUDA)
927 CUDASetLambdaAttrs(Method);
929 // Introduce the function call operator as the current declaration context.
930 PushDeclContext(CurScope, Method);
932 // Build the lambda scope.
933 buildLambdaScope(LSI, Method, Intro.Range, Intro.Default, Intro.DefaultLoc,
934 ExplicitParams, ExplicitResultType, !Method->isConst());
936 // C++11 [expr.prim.lambda]p9:
937 // A lambda-expression whose smallest enclosing scope is a block scope is a
938 // local lambda expression; any other lambda expression shall not have a
939 // capture-default or simple-capture in its lambda-introducer.
941 // For simple-captures, this is covered by the check below that any named
942 // entity is a variable that can be captured.
944 // For DR1632, we also allow a capture-default in any context where we can
945 // odr-use 'this' (in particular, in a default initializer for a non-static
947 if (Intro.Default != LCD_None && !Class->getParent()->isFunctionOrMethod() &&
948 (getCurrentThisType().isNull() ||
949 CheckCXXThisCapture(SourceLocation(), /*Explicit*/true,
950 /*BuildAndDiagnose*/false)))
951 Diag(Intro.DefaultLoc, diag::err_capture_default_non_local);
953 // Distinct capture names, for diagnostics.
954 llvm::SmallSet<IdentifierInfo*, 8> CaptureNames;
956 // Handle explicit captures.
957 SourceLocation PrevCaptureLoc
958 = Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
959 for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E;
960 PrevCaptureLoc = C->Loc, ++C) {
961 if (C->Kind == LCK_This || C->Kind == LCK_StarThis) {
962 if (C->Kind == LCK_StarThis)
963 Diag(C->Loc, !getLangOpts().CPlusPlus17
964 ? diag::ext_star_this_lambda_capture_cxx17
965 : diag::warn_cxx14_compat_star_this_lambda_capture);
967 // C++11 [expr.prim.lambda]p8:
968 // An identifier or this shall not appear more than once in a
970 if (LSI->isCXXThisCaptured()) {
971 Diag(C->Loc, diag::err_capture_more_than_once)
972 << "'this'" << SourceRange(LSI->getCXXThisCapture().getLocation())
973 << FixItHint::CreateRemoval(
974 SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
978 // C++2a [expr.prim.lambda]p8:
979 // If a lambda-capture includes a capture-default that is =,
980 // each simple-capture of that lambda-capture shall be of the form
981 // "&identifier", "this", or "* this". [ Note: The form [&,this] is
982 // redundant but accepted for compatibility with ISO C++14. --end note ]
983 if (Intro.Default == LCD_ByCopy && C->Kind != LCK_StarThis)
984 Diag(C->Loc, !getLangOpts().CPlusPlus2a
985 ? diag::ext_equals_this_lambda_capture_cxx2a
986 : diag::warn_cxx17_compat_equals_this_lambda_capture);
988 // C++11 [expr.prim.lambda]p12:
989 // If this is captured by a local lambda expression, its nearest
990 // enclosing function shall be a non-static member function.
991 QualType ThisCaptureType = getCurrentThisType();
992 if (ThisCaptureType.isNull()) {
993 Diag(C->Loc, diag::err_this_capture) << true;
997 CheckCXXThisCapture(C->Loc, /*Explicit=*/true, /*BuildAndDiagnose*/ true,
998 /*FunctionScopeIndexToStopAtPtr*/ nullptr,
999 C->Kind == LCK_StarThis);
1000 if (!LSI->Captures.empty())
1001 LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1005 assert(C->Id && "missing identifier for capture");
1007 if (C->Init.isInvalid())
1010 VarDecl *Var = nullptr;
1011 if (C->Init.isUsable()) {
1012 Diag(C->Loc, getLangOpts().CPlusPlus14
1013 ? diag::warn_cxx11_compat_init_capture
1014 : diag::ext_init_capture);
1016 if (C->Init.get()->containsUnexpandedParameterPack())
1017 ContainsUnexpandedParameterPack = true;
1018 // If the initializer expression is usable, but the InitCaptureType
1019 // is not, then an error has occurred - so ignore the capture for now.
1020 // for e.g., [n{0}] { }; <-- if no <initializer_list> is included.
1021 // FIXME: we should create the init capture variable and mark it invalid
1023 if (C->InitCaptureType.get().isNull())
1027 switch (C->InitKind) {
1028 case LambdaCaptureInitKind::NoInit:
1029 llvm_unreachable("not an init-capture?");
1030 case LambdaCaptureInitKind::CopyInit:
1031 InitStyle = VarDecl::CInit;
1033 case LambdaCaptureInitKind::DirectInit:
1034 InitStyle = VarDecl::CallInit;
1036 case LambdaCaptureInitKind::ListInit:
1037 InitStyle = VarDecl::ListInit;
1040 Var = createLambdaInitCaptureVarDecl(C->Loc, C->InitCaptureType.get(),
1041 C->Id, InitStyle, C->Init.get());
1042 // C++1y [expr.prim.lambda]p11:
1043 // An init-capture behaves as if it declares and explicitly
1044 // captures a variable [...] whose declarative region is the
1045 // lambda-expression's compound-statement
1047 PushOnScopeChains(Var, CurScope, false);
1049 assert(C->InitKind == LambdaCaptureInitKind::NoInit &&
1050 "init capture has valid but null init?");
1052 // C++11 [expr.prim.lambda]p8:
1053 // If a lambda-capture includes a capture-default that is &, the
1054 // identifiers in the lambda-capture shall not be preceded by &.
1055 // If a lambda-capture includes a capture-default that is =, [...]
1056 // each identifier it contains shall be preceded by &.
1057 if (C->Kind == LCK_ByRef && Intro.Default == LCD_ByRef) {
1058 Diag(C->Loc, diag::err_reference_capture_with_reference_default)
1059 << FixItHint::CreateRemoval(
1060 SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1062 } else if (C->Kind == LCK_ByCopy && Intro.Default == LCD_ByCopy) {
1063 Diag(C->Loc, diag::err_copy_capture_with_copy_default)
1064 << FixItHint::CreateRemoval(
1065 SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1069 // C++11 [expr.prim.lambda]p10:
1070 // The identifiers in a capture-list are looked up using the usual
1071 // rules for unqualified name lookup (3.4.1)
1072 DeclarationNameInfo Name(C->Id, C->Loc);
1073 LookupResult R(*this, Name, LookupOrdinaryName);
1074 LookupName(R, CurScope);
1075 if (R.isAmbiguous())
1078 // FIXME: Disable corrections that would add qualification?
1079 CXXScopeSpec ScopeSpec;
1080 if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R,
1081 llvm::make_unique<DeclFilterCCC<VarDecl>>()))
1085 Var = R.getAsSingle<VarDecl>();
1086 if (Var && DiagnoseUseOfDecl(Var, C->Loc))
1090 // C++11 [expr.prim.lambda]p8:
1091 // An identifier or this shall not appear more than once in a
1093 if (!CaptureNames.insert(C->Id).second) {
1094 if (Var && LSI->isCaptured(Var)) {
1095 Diag(C->Loc, diag::err_capture_more_than_once)
1096 << C->Id << SourceRange(LSI->getCapture(Var).getLocation())
1097 << FixItHint::CreateRemoval(
1098 SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1100 // Previous capture captured something different (one or both was
1101 // an init-cpature): no fixit.
1102 Diag(C->Loc, diag::err_capture_more_than_once) << C->Id;
1106 // C++11 [expr.prim.lambda]p10:
1107 // [...] each such lookup shall find a variable with automatic storage
1108 // duration declared in the reaching scope of the local lambda expression.
1109 // Note that the 'reaching scope' check happens in tryCaptureVariable().
1111 Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id;
1115 // Ignore invalid decls; they'll just confuse the code later.
1116 if (Var->isInvalidDecl())
1119 if (!Var->hasLocalStorage()) {
1120 Diag(C->Loc, diag::err_capture_non_automatic_variable) << C->Id;
1121 Diag(Var->getLocation(), diag::note_previous_decl) << C->Id;
1125 // C++11 [expr.prim.lambda]p23:
1126 // A capture followed by an ellipsis is a pack expansion (14.5.3).
1127 SourceLocation EllipsisLoc;
1128 if (C->EllipsisLoc.isValid()) {
1129 if (Var->isParameterPack()) {
1130 EllipsisLoc = C->EllipsisLoc;
1132 Diag(C->EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
1133 << SourceRange(C->Loc);
1135 // Just ignore the ellipsis.
1137 } else if (Var->isParameterPack()) {
1138 ContainsUnexpandedParameterPack = true;
1141 if (C->Init.isUsable()) {
1142 buildInitCaptureField(LSI, Var);
1144 TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef :
1145 TryCapture_ExplicitByVal;
1146 tryCaptureVariable(Var, C->Loc, Kind, EllipsisLoc);
1148 if (!LSI->Captures.empty())
1149 LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1151 finishLambdaExplicitCaptures(LSI);
1153 LSI->ContainsUnexpandedParameterPack = ContainsUnexpandedParameterPack;
1155 // Add lambda parameters into scope.
1156 addLambdaParameters(Method, CurScope);
1158 // Enter a new evaluation context to insulate the lambda from any
1159 // cleanups from the enclosing full-expression.
1160 PushExpressionEvaluationContext(
1161 ExpressionEvaluationContext::PotentiallyEvaluated);
1164 void Sema::ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
1165 bool IsInstantiation) {
1166 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(FunctionScopes.back());
1168 // Leave the expression-evaluation context.
1169 DiscardCleanupsInEvaluationContext();
1170 PopExpressionEvaluationContext();
1172 // Leave the context of the lambda.
1173 if (!IsInstantiation)
1176 // Finalize the lambda.
1177 CXXRecordDecl *Class = LSI->Lambda;
1178 Class->setInvalidDecl();
1179 SmallVector<Decl*, 4> Fields(Class->fields());
1180 ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1181 SourceLocation(), ParsedAttributesView());
1182 CheckCompletedCXXClass(Class);
1184 PopFunctionScopeInfo();
1187 QualType Sema::getLambdaConversionFunctionResultType(
1188 const FunctionProtoType *CallOpProto) {
1189 // The function type inside the pointer type is the same as the call
1190 // operator with some tweaks. The calling convention is the default free
1191 // function convention, and the type qualifications are lost.
1192 const FunctionProtoType::ExtProtoInfo CallOpExtInfo =
1193 CallOpProto->getExtProtoInfo();
1194 FunctionProtoType::ExtProtoInfo InvokerExtInfo = CallOpExtInfo;
1195 CallingConv CC = Context.getDefaultCallingConvention(
1196 CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
1197 InvokerExtInfo.ExtInfo = InvokerExtInfo.ExtInfo.withCallingConv(CC);
1198 InvokerExtInfo.TypeQuals = 0;
1199 assert(InvokerExtInfo.RefQualifier == RQ_None &&
1200 "Lambda's call operator should not have a reference qualifier");
1201 return Context.getFunctionType(CallOpProto->getReturnType(),
1202 CallOpProto->getParamTypes(), InvokerExtInfo);
1205 /// Add a lambda's conversion to function pointer, as described in
1206 /// C++11 [expr.prim.lambda]p6.
1207 static void addFunctionPointerConversion(Sema &S,
1208 SourceRange IntroducerRange,
1209 CXXRecordDecl *Class,
1210 CXXMethodDecl *CallOperator) {
1211 // This conversion is explicitly disabled if the lambda's function has
1212 // pass_object_size attributes on any of its parameters.
1213 auto HasPassObjectSizeAttr = [](const ParmVarDecl *P) {
1214 return P->hasAttr<PassObjectSizeAttr>();
1216 if (llvm::any_of(CallOperator->parameters(), HasPassObjectSizeAttr))
1219 // Add the conversion to function pointer.
1220 QualType InvokerFunctionTy = S.getLambdaConversionFunctionResultType(
1221 CallOperator->getType()->castAs<FunctionProtoType>());
1222 QualType PtrToFunctionTy = S.Context.getPointerType(InvokerFunctionTy);
1224 // Create the type of the conversion function.
1225 FunctionProtoType::ExtProtoInfo ConvExtInfo(
1226 S.Context.getDefaultCallingConvention(
1227 /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1228 // The conversion function is always const.
1229 ConvExtInfo.TypeQuals = Qualifiers::Const;
1231 S.Context.getFunctionType(PtrToFunctionTy, None, ConvExtInfo);
1233 SourceLocation Loc = IntroducerRange.getBegin();
1234 DeclarationName ConversionName
1235 = S.Context.DeclarationNames.getCXXConversionFunctionName(
1236 S.Context.getCanonicalType(PtrToFunctionTy));
1237 DeclarationNameLoc ConvNameLoc;
1238 // Construct a TypeSourceInfo for the conversion function, and wire
1239 // all the parameters appropriately for the FunctionProtoTypeLoc
1240 // so that everything works during transformation/instantiation of
1242 // The main reason for wiring up the parameters of the conversion
1243 // function with that of the call operator is so that constructs
1244 // like the following work:
1245 // auto L = [](auto b) { <-- 1
1246 // return [](auto a) -> decltype(a) { <-- 2
1250 // int (*fp)(int) = L(5);
1251 // Because the trailing return type can contain DeclRefExprs that refer
1252 // to the original call operator's variables, we hijack the call
1253 // operators ParmVarDecls below.
1254 TypeSourceInfo *ConvNamePtrToFunctionTSI =
1255 S.Context.getTrivialTypeSourceInfo(PtrToFunctionTy, Loc);
1256 ConvNameLoc.NamedType.TInfo = ConvNamePtrToFunctionTSI;
1258 // The conversion function is a conversion to a pointer-to-function.
1259 TypeSourceInfo *ConvTSI = S.Context.getTrivialTypeSourceInfo(ConvTy, Loc);
1260 FunctionProtoTypeLoc ConvTL =
1261 ConvTSI->getTypeLoc().getAs<FunctionProtoTypeLoc>();
1262 // Get the result of the conversion function which is a pointer-to-function.
1263 PointerTypeLoc PtrToFunctionTL =
1264 ConvTL.getReturnLoc().getAs<PointerTypeLoc>();
1265 // Do the same for the TypeSourceInfo that is used to name the conversion
1267 PointerTypeLoc ConvNamePtrToFunctionTL =
1268 ConvNamePtrToFunctionTSI->getTypeLoc().getAs<PointerTypeLoc>();
1270 // Get the underlying function types that the conversion function will
1271 // be converting to (should match the type of the call operator).
1272 FunctionProtoTypeLoc CallOpConvTL =
1273 PtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1274 FunctionProtoTypeLoc CallOpConvNameTL =
1275 ConvNamePtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1277 // Wire up the FunctionProtoTypeLocs with the call operator's parameters.
1278 // These parameter's are essentially used to transform the name and
1279 // the type of the conversion operator. By using the same parameters
1280 // as the call operator's we don't have to fix any back references that
1281 // the trailing return type of the call operator's uses (such as
1282 // decltype(some_type<decltype(a)>::type{} + decltype(a){}) etc.)
1283 // - we can simply use the return type of the call operator, and
1284 // everything should work.
1285 SmallVector<ParmVarDecl *, 4> InvokerParams;
1286 for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1287 ParmVarDecl *From = CallOperator->getParamDecl(I);
1289 InvokerParams.push_back(ParmVarDecl::Create(S.Context,
1290 // Temporarily add to the TU. This is set to the invoker below.
1291 S.Context.getTranslationUnitDecl(),
1292 From->getLocStart(),
1293 From->getLocation(),
1294 From->getIdentifier(),
1296 From->getTypeSourceInfo(),
1297 From->getStorageClass(),
1298 /*DefaultArg=*/nullptr));
1299 CallOpConvTL.setParam(I, From);
1300 CallOpConvNameTL.setParam(I, From);
1303 CXXConversionDecl *Conversion
1304 = CXXConversionDecl::Create(S.Context, Class, Loc,
1305 DeclarationNameInfo(ConversionName,
1309 /*isInline=*/true, /*isExplicit=*/false,
1310 /*isConstexpr=*/S.getLangOpts().CPlusPlus17,
1311 CallOperator->getBody()->getLocEnd());
1312 Conversion->setAccess(AS_public);
1313 Conversion->setImplicit(true);
1315 if (Class->isGenericLambda()) {
1316 // Create a template version of the conversion operator, using the template
1317 // parameter list of the function call operator.
1318 FunctionTemplateDecl *TemplateCallOperator =
1319 CallOperator->getDescribedFunctionTemplate();
1320 FunctionTemplateDecl *ConversionTemplate =
1321 FunctionTemplateDecl::Create(S.Context, Class,
1322 Loc, ConversionName,
1323 TemplateCallOperator->getTemplateParameters(),
1325 ConversionTemplate->setAccess(AS_public);
1326 ConversionTemplate->setImplicit(true);
1327 Conversion->setDescribedFunctionTemplate(ConversionTemplate);
1328 Class->addDecl(ConversionTemplate);
1330 Class->addDecl(Conversion);
1331 // Add a non-static member function that will be the result of
1332 // the conversion with a certain unique ID.
1333 DeclarationName InvokerName = &S.Context.Idents.get(
1334 getLambdaStaticInvokerName());
1335 // FIXME: Instead of passing in the CallOperator->getTypeSourceInfo()
1336 // we should get a prebuilt TrivialTypeSourceInfo from Context
1337 // using FunctionTy & Loc and get its TypeLoc as a FunctionProtoTypeLoc
1338 // then rewire the parameters accordingly, by hoisting up the InvokeParams
1339 // loop below and then use its Params to set Invoke->setParams(...) below.
1340 // This would avoid the 'const' qualifier of the calloperator from
1341 // contaminating the type of the invoker, which is currently adjusted
1342 // in SemaTemplateDeduction.cpp:DeduceTemplateArguments. Fixing the
1343 // trailing return type of the invoker would require a visitor to rebuild
1344 // the trailing return type and adjusting all back DeclRefExpr's to refer
1345 // to the new static invoker parameters - not the call operator's.
1346 CXXMethodDecl *Invoke
1347 = CXXMethodDecl::Create(S.Context, Class, Loc,
1348 DeclarationNameInfo(InvokerName, Loc),
1350 CallOperator->getTypeSourceInfo(),
1351 SC_Static, /*IsInline=*/true,
1352 /*IsConstexpr=*/false,
1353 CallOperator->getBody()->getLocEnd());
1354 for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I)
1355 InvokerParams[I]->setOwningFunction(Invoke);
1356 Invoke->setParams(InvokerParams);
1357 Invoke->setAccess(AS_private);
1358 Invoke->setImplicit(true);
1359 if (Class->isGenericLambda()) {
1360 FunctionTemplateDecl *TemplateCallOperator =
1361 CallOperator->getDescribedFunctionTemplate();
1362 FunctionTemplateDecl *StaticInvokerTemplate = FunctionTemplateDecl::Create(
1363 S.Context, Class, Loc, InvokerName,
1364 TemplateCallOperator->getTemplateParameters(),
1366 StaticInvokerTemplate->setAccess(AS_private);
1367 StaticInvokerTemplate->setImplicit(true);
1368 Invoke->setDescribedFunctionTemplate(StaticInvokerTemplate);
1369 Class->addDecl(StaticInvokerTemplate);
1371 Class->addDecl(Invoke);
1374 /// Add a lambda's conversion to block pointer.
1375 static void addBlockPointerConversion(Sema &S,
1376 SourceRange IntroducerRange,
1377 CXXRecordDecl *Class,
1378 CXXMethodDecl *CallOperator) {
1379 QualType FunctionTy = S.getLambdaConversionFunctionResultType(
1380 CallOperator->getType()->castAs<FunctionProtoType>());
1381 QualType BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
1383 FunctionProtoType::ExtProtoInfo ConversionEPI(
1384 S.Context.getDefaultCallingConvention(
1385 /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1386 ConversionEPI.TypeQuals = Qualifiers::Const;
1387 QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, None, ConversionEPI);
1389 SourceLocation Loc = IntroducerRange.getBegin();
1390 DeclarationName Name
1391 = S.Context.DeclarationNames.getCXXConversionFunctionName(
1392 S.Context.getCanonicalType(BlockPtrTy));
1393 DeclarationNameLoc NameLoc;
1394 NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc);
1395 CXXConversionDecl *Conversion
1396 = CXXConversionDecl::Create(S.Context, Class, Loc,
1397 DeclarationNameInfo(Name, Loc, NameLoc),
1399 S.Context.getTrivialTypeSourceInfo(ConvTy, Loc),
1400 /*isInline=*/true, /*isExplicit=*/false,
1401 /*isConstexpr=*/false,
1402 CallOperator->getBody()->getLocEnd());
1403 Conversion->setAccess(AS_public);
1404 Conversion->setImplicit(true);
1405 Class->addDecl(Conversion);
1408 static ExprResult performLambdaVarCaptureInitialization(Sema &S,
1409 const Capture &Capture,
1411 assert(Capture.isVariableCapture() && "not a variable capture");
1413 auto *Var = Capture.getVariable();
1414 SourceLocation Loc = Capture.getLocation();
1416 // C++11 [expr.prim.lambda]p21:
1417 // When the lambda-expression is evaluated, the entities that
1418 // are captured by copy are used to direct-initialize each
1419 // corresponding non-static data member of the resulting closure
1420 // object. (For array members, the array elements are
1421 // direct-initialized in increasing subscript order.) These
1422 // initializations are performed in the (unspecified) order in
1423 // which the non-static data members are declared.
1425 // C++ [expr.prim.lambda]p12:
1426 // An entity captured by a lambda-expression is odr-used (3.2) in
1427 // the scope containing the lambda-expression.
1428 ExprResult RefResult = S.BuildDeclarationNameExpr(
1429 CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), Loc), Var);
1430 if (RefResult.isInvalid())
1432 Expr *Ref = RefResult.get();
1434 auto Entity = InitializedEntity::InitializeLambdaCapture(
1435 Var->getIdentifier(), Field->getType(), Loc);
1436 InitializationKind InitKind = InitializationKind::CreateDirect(Loc, Loc, Loc);
1437 InitializationSequence Init(S, Entity, InitKind, Ref);
1438 return Init.Perform(S, Entity, InitKind, Ref);
1441 ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body,
1443 LambdaScopeInfo LSI = *cast<LambdaScopeInfo>(FunctionScopes.back());
1444 ActOnFinishFunctionBody(LSI.CallOperator, Body);
1445 return BuildLambdaExpr(StartLoc, Body->getLocEnd(), &LSI);
1448 static LambdaCaptureDefault
1449 mapImplicitCaptureStyle(CapturingScopeInfo::ImplicitCaptureStyle ICS) {
1451 case CapturingScopeInfo::ImpCap_None:
1453 case CapturingScopeInfo::ImpCap_LambdaByval:
1455 case CapturingScopeInfo::ImpCap_CapturedRegion:
1456 case CapturingScopeInfo::ImpCap_LambdaByref:
1458 case CapturingScopeInfo::ImpCap_Block:
1459 llvm_unreachable("block capture in lambda");
1461 llvm_unreachable("Unknown implicit capture style");
1464 bool Sema::CaptureHasSideEffects(const Capture &From) {
1465 if (!From.isVLATypeCapture()) {
1466 Expr *Init = From.getInitExpr();
1467 if (Init && Init->HasSideEffects(Context))
1471 if (!From.isCopyCapture())
1474 const QualType T = From.isThisCapture()
1475 ? getCurrentThisType()->getPointeeType()
1476 : From.getCaptureType();
1478 if (T.isVolatileQualified())
1481 const Type *BaseT = T->getBaseElementTypeUnsafe();
1482 if (const CXXRecordDecl *RD = BaseT->getAsCXXRecordDecl())
1483 return !RD->isCompleteDefinition() || !RD->hasTrivialCopyConstructor() ||
1484 !RD->hasTrivialDestructor();
1489 bool Sema::DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
1490 const Capture &From) {
1491 if (CaptureHasSideEffects(From))
1494 if (From.isVLATypeCapture())
1497 auto diag = Diag(From.getLocation(), diag::warn_unused_lambda_capture);
1498 if (From.isThisCapture())
1501 diag << From.getVariable();
1502 diag << From.isNonODRUsed();
1503 diag << FixItHint::CreateRemoval(CaptureRange);
1507 ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
1508 LambdaScopeInfo *LSI) {
1509 // Collect information from the lambda scope.
1510 SmallVector<LambdaCapture, 4> Captures;
1511 SmallVector<Expr *, 4> CaptureInits;
1512 SourceLocation CaptureDefaultLoc = LSI->CaptureDefaultLoc;
1513 LambdaCaptureDefault CaptureDefault =
1514 mapImplicitCaptureStyle(LSI->ImpCaptureStyle);
1515 CXXRecordDecl *Class;
1516 CXXMethodDecl *CallOperator;
1517 SourceRange IntroducerRange;
1518 bool ExplicitParams;
1519 bool ExplicitResultType;
1520 CleanupInfo LambdaCleanup;
1521 bool ContainsUnexpandedParameterPack;
1522 bool IsGenericLambda;
1524 CallOperator = LSI->CallOperator;
1525 Class = LSI->Lambda;
1526 IntroducerRange = LSI->IntroducerRange;
1527 ExplicitParams = LSI->ExplicitParams;
1528 ExplicitResultType = !LSI->HasImplicitReturnType;
1529 LambdaCleanup = LSI->Cleanup;
1530 ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack;
1531 IsGenericLambda = Class->isGenericLambda();
1533 CallOperator->setLexicalDeclContext(Class);
1534 Decl *TemplateOrNonTemplateCallOperatorDecl =
1535 CallOperator->getDescribedFunctionTemplate()
1536 ? CallOperator->getDescribedFunctionTemplate()
1537 : cast<Decl>(CallOperator);
1539 TemplateOrNonTemplateCallOperatorDecl->setLexicalDeclContext(Class);
1540 Class->addDecl(TemplateOrNonTemplateCallOperatorDecl);
1542 PopExpressionEvaluationContext();
1544 // Translate captures.
1545 auto CurField = Class->field_begin();
1546 // True if the current capture has a used capture or default before it.
1547 bool CurHasPreviousCapture = CaptureDefault != LCD_None;
1548 SourceLocation PrevCaptureLoc = CurHasPreviousCapture ?
1549 CaptureDefaultLoc : IntroducerRange.getBegin();
1551 for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I, ++CurField) {
1552 const Capture &From = LSI->Captures[I];
1554 assert(!From.isBlockCapture() && "Cannot capture __block variables");
1555 bool IsImplicit = I >= LSI->NumExplicitCaptures;
1557 // Use source ranges of explicit captures for fixits where available.
1558 SourceRange CaptureRange = LSI->ExplicitCaptureRanges[I];
1560 // Warn about unused explicit captures.
1561 bool IsCaptureUsed = true;
1562 if (!CurContext->isDependentContext() && !IsImplicit && !From.isODRUsed()) {
1563 // Initialized captures that are non-ODR used may not be eliminated.
1564 bool NonODRUsedInitCapture =
1565 IsGenericLambda && From.isNonODRUsed() && From.getInitExpr();
1566 if (!NonODRUsedInitCapture) {
1567 bool IsLast = (I + 1) == LSI->NumExplicitCaptures;
1568 SourceRange FixItRange;
1569 if (CaptureRange.isValid()) {
1570 if (!CurHasPreviousCapture && !IsLast) {
1571 // If there are no captures preceding this capture, remove the
1573 FixItRange = SourceRange(CaptureRange.getBegin(),
1574 getLocForEndOfToken(CaptureRange.getEnd()));
1576 // Otherwise, remove the comma since the last used capture.
1577 FixItRange = SourceRange(getLocForEndOfToken(PrevCaptureLoc),
1578 CaptureRange.getEnd());
1582 IsCaptureUsed = !DiagnoseUnusedLambdaCapture(FixItRange, From);
1586 if (CaptureRange.isValid()) {
1587 CurHasPreviousCapture |= IsCaptureUsed;
1588 PrevCaptureLoc = CaptureRange.getEnd();
1591 // Handle 'this' capture.
1592 if (From.isThisCapture()) {
1593 // Capturing 'this' implicitly with a default of '[=]' is deprecated,
1594 // because it results in a reference capture. Don't warn prior to
1595 // C++2a; there's nothing that can be done about it before then.
1596 if (getLangOpts().CPlusPlus2a && IsImplicit &&
1597 CaptureDefault == LCD_ByCopy) {
1598 Diag(From.getLocation(), diag::warn_deprecated_this_capture);
1599 Diag(CaptureDefaultLoc, diag::note_deprecated_this_capture)
1600 << FixItHint::CreateInsertion(
1601 getLocForEndOfToken(CaptureDefaultLoc), ", this");
1605 LambdaCapture(From.getLocation(), IsImplicit,
1606 From.isCopyCapture() ? LCK_StarThis : LCK_This));
1607 CaptureInits.push_back(From.getInitExpr());
1610 if (From.isVLATypeCapture()) {
1612 LambdaCapture(From.getLocation(), IsImplicit, LCK_VLAType));
1613 CaptureInits.push_back(nullptr);
1617 VarDecl *Var = From.getVariable();
1618 LambdaCaptureKind Kind = From.isCopyCapture() ? LCK_ByCopy : LCK_ByRef;
1619 Captures.push_back(LambdaCapture(From.getLocation(), IsImplicit, Kind,
1620 Var, From.getEllipsisLoc()));
1621 Expr *Init = From.getInitExpr();
1624 performLambdaVarCaptureInitialization(*this, From, *CurField);
1625 if (InitResult.isInvalid())
1627 Init = InitResult.get();
1629 CaptureInits.push_back(Init);
1632 // C++11 [expr.prim.lambda]p6:
1633 // The closure type for a lambda-expression with no lambda-capture
1634 // has a public non-virtual non-explicit const conversion function
1635 // to pointer to function having the same parameter and return
1636 // types as the closure type's function call operator.
1637 if (Captures.empty() && CaptureDefault == LCD_None)
1638 addFunctionPointerConversion(*this, IntroducerRange, Class,
1642 // The closure type for a lambda-expression has a public non-virtual
1643 // non-explicit const conversion function to a block pointer having the
1644 // same parameter and return types as the closure type's function call
1646 // FIXME: Fix generic lambda to block conversions.
1647 if (getLangOpts().Blocks && getLangOpts().ObjC1 && !IsGenericLambda)
1648 addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator);
1650 // Finalize the lambda class.
1651 SmallVector<Decl*, 4> Fields(Class->fields());
1652 ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1653 SourceLocation(), ParsedAttributesView());
1654 CheckCompletedCXXClass(Class);
1657 Cleanup.mergeFrom(LambdaCleanup);
1659 LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
1660 CaptureDefault, CaptureDefaultLoc,
1662 ExplicitParams, ExplicitResultType,
1663 CaptureInits, EndLoc,
1664 ContainsUnexpandedParameterPack);
1665 // If the lambda expression's call operator is not explicitly marked constexpr
1666 // and we are not in a dependent context, analyze the call operator to infer
1667 // its constexpr-ness, suppressing diagnostics while doing so.
1668 if (getLangOpts().CPlusPlus17 && !CallOperator->isInvalidDecl() &&
1669 !CallOperator->isConstexpr() &&
1670 !isa<CoroutineBodyStmt>(CallOperator->getBody()) &&
1671 !Class->getDeclContext()->isDependentContext()) {
1672 TentativeAnalysisScope DiagnosticScopeGuard(*this);
1673 CallOperator->setConstexpr(
1674 CheckConstexprFunctionDecl(CallOperator) &&
1675 CheckConstexprFunctionBody(CallOperator, CallOperator->getBody()));
1678 // Emit delayed shadowing warnings now that the full capture list is known.
1679 DiagnoseShadowingLambdaDecls(LSI);
1681 if (!CurContext->isDependentContext()) {
1682 switch (ExprEvalContexts.back().Context) {
1683 // C++11 [expr.prim.lambda]p2:
1684 // A lambda-expression shall not appear in an unevaluated operand
1686 case ExpressionEvaluationContext::Unevaluated:
1687 case ExpressionEvaluationContext::UnevaluatedList:
1688 case ExpressionEvaluationContext::UnevaluatedAbstract:
1689 // C++1y [expr.const]p2:
1690 // A conditional-expression e is a core constant expression unless the
1691 // evaluation of e, following the rules of the abstract machine, would
1692 // evaluate [...] a lambda-expression.
1694 // This is technically incorrect, there are some constant evaluated contexts
1695 // where this should be allowed. We should probably fix this when DR1607 is
1696 // ratified, it lays out the exact set of conditions where we shouldn't
1697 // allow a lambda-expression.
1698 case ExpressionEvaluationContext::ConstantEvaluated:
1699 // We don't actually diagnose this case immediately, because we
1700 // could be within a context where we might find out later that
1701 // the expression is potentially evaluated (e.g., for typeid).
1702 ExprEvalContexts.back().Lambdas.push_back(Lambda);
1705 case ExpressionEvaluationContext::DiscardedStatement:
1706 case ExpressionEvaluationContext::PotentiallyEvaluated:
1707 case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
1712 return MaybeBindToTemporary(Lambda);
1715 ExprResult Sema::BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
1716 SourceLocation ConvLocation,
1717 CXXConversionDecl *Conv,
1719 // Make sure that the lambda call operator is marked used.
1720 CXXRecordDecl *Lambda = Conv->getParent();
1721 CXXMethodDecl *CallOperator
1722 = cast<CXXMethodDecl>(
1724 Context.DeclarationNames.getCXXOperatorName(OO_Call)).front());
1725 CallOperator->setReferenced();
1726 CallOperator->markUsed(Context);
1728 ExprResult Init = PerformCopyInitialization(
1729 InitializedEntity::InitializeLambdaToBlock(ConvLocation, Src->getType(),
1731 CurrentLocation, Src);
1732 if (!Init.isInvalid())
1733 Init = ActOnFinishFullExpr(Init.get());
1735 if (Init.isInvalid())
1738 // Create the new block to be returned.
1739 BlockDecl *Block = BlockDecl::Create(Context, CurContext, ConvLocation);
1741 // Set the type information.
1742 Block->setSignatureAsWritten(CallOperator->getTypeSourceInfo());
1743 Block->setIsVariadic(CallOperator->isVariadic());
1744 Block->setBlockMissingReturnType(false);
1747 SmallVector<ParmVarDecl *, 4> BlockParams;
1748 for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1749 ParmVarDecl *From = CallOperator->getParamDecl(I);
1750 BlockParams.push_back(ParmVarDecl::Create(Context, Block,
1751 From->getLocStart(),
1752 From->getLocation(),
1753 From->getIdentifier(),
1755 From->getTypeSourceInfo(),
1756 From->getStorageClass(),
1757 /*DefaultArg=*/nullptr));
1759 Block->setParams(BlockParams);
1761 Block->setIsConversionFromLambda(true);
1763 // Add capture. The capture uses a fake variable, which doesn't correspond
1764 // to any actual memory location. However, the initializer copy-initializes
1765 // the lambda object.
1766 TypeSourceInfo *CapVarTSI =
1767 Context.getTrivialTypeSourceInfo(Src->getType());
1768 VarDecl *CapVar = VarDecl::Create(Context, Block, ConvLocation,
1769 ConvLocation, nullptr,
1770 Src->getType(), CapVarTSI,
1772 BlockDecl::Capture Capture(/*Variable=*/CapVar, /*ByRef=*/false,
1773 /*Nested=*/false, /*Copy=*/Init.get());
1774 Block->setCaptures(Context, Capture, /*CapturesCXXThis=*/false);
1776 // Add a fake function body to the block. IR generation is responsible
1777 // for filling in the actual body, which cannot be expressed as an AST.
1778 Block->setBody(new (Context) CompoundStmt(ConvLocation));
1780 // Create the block literal expression.
1781 Expr *BuildBlock = new (Context) BlockExpr(Block, Conv->getConversionType());
1782 ExprCleanupObjects.push_back(Block);
1783 Cleanup.setExprNeedsCleanups(true);