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llvm-project/clang/lib/Sema/SemaLambda.cpp
Douglas Gregor 7fcbd902b4 Implement name mangling for lambda expressions that occur within the 
default arguments of function parameters. This simple-sounding task is
complicated greatly by two issues:

  (1) Default arguments aren't actually a real context, so we need to
  maintain extra state within lambda expressions to track when a
  lambda was actually in a default argument.
  (2) At the time that we parse a default argument, the FunctionDecl
  doesn't exist yet, so lambda closure types end up in the enclosing
  context. It's not clear that we ever want to change that, so instead
  we introduce the notion of the "effective" context of a declaration
  for the purposes of name mangling.

llvm-svn: 151011
2012-02-21 00:37:24 +00:00

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//===--- 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 "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/AST/ExprCXX.h"
using namespace clang;
using namespace sema;
CXXRecordDecl *Sema::createLambdaClosureType(SourceRange IntroducerRange) {
DeclContext *DC = CurContext;
while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
DC = DC->getParent();
// Start constructing the lambda class.
CXXRecordDecl *Class = CXXRecordDecl::CreateLambda(Context, DC,
IntroducerRange.getBegin());
DC->addDecl(Class);
return Class;
}
CXXMethodDecl *Sema::startLambdaDefinition(CXXRecordDecl *Class,
SourceRange IntroducerRange,
TypeSourceInfo *MethodType,
SourceLocation EndLoc,
llvm::ArrayRef<ParmVarDecl *> Params) {
// 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->getType(), MethodType,
/*isStatic=*/false,
SC_None,
/*isInline=*/true,
/*isConstExpr=*/false,
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);
// Add parameters.
if (!Params.empty()) {
Method->setParams(Params);
CheckParmsForFunctionDef(const_cast<ParmVarDecl **>(Params.begin()),
const_cast<ParmVarDecl **>(Params.end()),
/*CheckParameterNames=*/false);
for (CXXMethodDecl::param_iterator P = Method->param_begin(),
PEnd = Method->param_end();
P != PEnd; ++P)
(*P)->setOwningFunction(Method);
}
return Method;
}
LambdaScopeInfo *Sema::enterLambdaScope(CXXMethodDecl *CallOperator,
SourceRange IntroducerRange,
LambdaCaptureDefault CaptureDefault,
bool ExplicitParams,
bool ExplicitResultType,
bool Mutable) {
PushLambdaScope(CallOperator->getParent(), CallOperator);
LambdaScopeInfo *LSI = getCurLambda();
if (CaptureDefault == LCD_ByCopy)
LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByval;
else if (CaptureDefault == LCD_ByRef)
LSI->ImpCaptureStyle = LambdaScopeInfo::ImpCap_LambdaByref;
LSI->IntroducerRange = IntroducerRange;
LSI->ExplicitParams = ExplicitParams;
LSI->Mutable = Mutable;
if (ExplicitResultType) {
LSI->ReturnType = CallOperator->getResultType();
if (!LSI->ReturnType->isDependentType() &&
!LSI->ReturnType->isVoidType()) {
if (RequireCompleteType(CallOperator->getLocStart(), LSI->ReturnType,
diag::err_lambda_incomplete_result)) {
// Do nothing.
} else if (LSI->ReturnType->isObjCObjectOrInterfaceType()) {
Diag(CallOperator->getLocStart(), diag::err_lambda_objc_object_result)
<< LSI->ReturnType;
}
}
} else {
LSI->HasImplicitReturnType = true;
}
return LSI;
}
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);
}
}
}
void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
Declarator &ParamInfo,
Scope *CurScope) {
CXXRecordDecl *Class = createLambdaClosureType(Intro.Range);
// Determine the signature of the call operator.
TypeSourceInfo *MethodTyInfo;
bool ExplicitParams = true;
bool ExplicitResultType = true;
SourceLocation EndLoc;
llvm::ArrayRef<ParmVarDecl *> 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;
EPI.HasTrailingReturn = true;
EPI.TypeQuals |= DeclSpec::TQ_const;
QualType MethodTy = Context.getFunctionType(Context.DependentTy,
/*Args=*/0, /*NumArgs=*/0, 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
= MethodTyInfo->getType()->getAs<FunctionType>()->getResultType()
!= Context.DependentTy;
TypeLoc TL = MethodTyInfo->getTypeLoc();
FunctionProtoTypeLoc Proto = cast<FunctionProtoTypeLoc>(TL);
Params = llvm::ArrayRef<ParmVarDecl *>(Proto.getParmArray(),
Proto.getNumArgs());
}
CXXMethodDecl *Method = startLambdaDefinition(Class, Intro.Range,
MethodTyInfo, EndLoc, Params);
if (ExplicitParams)
CheckCXXDefaultArguments(Method);
// Attributes on the lambda apply to the method.
ProcessDeclAttributes(CurScope, Method, ParamInfo);
// Introduce the function call operator as the current declaration context.
PushDeclContext(CurScope, Method);
// Introduce the lambda scope.
LambdaScopeInfo *LSI
= enterLambdaScope(Method, Intro.Range, Intro.Default, ExplicitParams,
ExplicitResultType,
(Method->getTypeQualifiers() & Qualifiers::Const) == 0);
// Handle explicit captures.
SourceLocation PrevCaptureLoc
= Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
for (llvm::SmallVector<LambdaCapture, 4>::const_iterator
C = Intro.Captures.begin(),
E = Intro.Captures.end();
C != E;
PrevCaptureLoc = C->Loc, ++C) {
if (C->Kind == LCK_This) {
// 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(PP.getLocForEndOfToken(PrevCaptureLoc), C->Loc));
continue;
}
// C++11 [expr.prim.lambda]p8:
// If a lambda-capture includes a capture-default that is =, the
// lambda-capture shall not contain this [...].
if (Intro.Default == LCD_ByCopy) {
Diag(C->Loc, diag::err_this_capture_with_copy_default)
<< FixItHint::CreateRemoval(
SourceRange(PP.getLocForEndOfToken(PrevCaptureLoc), C->Loc));
continue;
}
// 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);
continue;
}
assert(C->Id && "missing identifier for capture");
// 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(PP.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(PP.getLocForEndOfToken(PrevCaptureLoc), C->Loc));
continue;
}
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;
DeclFilterCCC<VarDecl> Validator;
if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R, Validator))
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); 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().
VarDecl *Var = R.getAsSingle<VarDecl>();
if (!Var) {
Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id;
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]p8:
// An identifier or this shall not appear more than once in a
// lambda-capture.
if (LSI->isCaptured(Var)) {
Diag(C->Loc, diag::err_capture_more_than_once)
<< C->Id
<< SourceRange(LSI->getCapture(Var).getLocation())
<< FixItHint::CreateRemoval(
SourceRange(PP.getLocForEndOfToken(PrevCaptureLoc), C->Loc));
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()) {
Diag(C->Loc, diag::err_lambda_unexpanded_pack);
continue;
}
TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef :
TryCapture_ExplicitByVal;
tryCaptureVariable(Var, C->Loc, Kind, EllipsisLoc);
}
finishLambdaExplicitCaptures(LSI);
// 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(PotentiallyEvaluated);
}
void Sema::ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
bool IsInstantiation) {
// Leave the expression-evaluation context.
DiscardCleanupsInEvaluationContext();
PopExpressionEvaluationContext();
// Leave the context of the lambda.
if (!IsInstantiation)
PopDeclContext();
// Finalize the lambda.
LambdaScopeInfo *LSI = getCurLambda();
CXXRecordDecl *Class = LSI->Lambda;
Class->setInvalidDecl();
SmallVector<Decl*, 4> Fields(Class->field_begin(), Class->field_end());
ActOnFields(0, Class->getLocation(), Class, Fields,
SourceLocation(), SourceLocation(), 0);
CheckCompletedCXXClass(Class);
PopFunctionScopeInfo();
}
/// \brief 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) {
// Add the conversion to function pointer.
const FunctionProtoType *Proto
= CallOperator->getType()->getAs<FunctionProtoType>();
QualType FunctionPtrTy;
QualType FunctionTy;
{
FunctionProtoType::ExtProtoInfo ExtInfo = Proto->getExtProtoInfo();
ExtInfo.TypeQuals = 0;
FunctionTy = S.Context.getFunctionType(Proto->getResultType(),
Proto->arg_type_begin(),
Proto->getNumArgs(),
ExtInfo);
FunctionPtrTy = S.Context.getPointerType(FunctionTy);
}
FunctionProtoType::ExtProtoInfo ExtInfo;
ExtInfo.TypeQuals = Qualifiers::Const;
QualType ConvTy = S.Context.getFunctionType(FunctionPtrTy, 0, 0, ExtInfo);
SourceLocation Loc = IntroducerRange.getBegin();
DeclarationName Name
= S.Context.DeclarationNames.getCXXConversionFunctionName(
S.Context.getCanonicalType(FunctionPtrTy));
DeclarationNameLoc NameLoc;
NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(FunctionPtrTy,
Loc);
CXXConversionDecl *Conversion
= CXXConversionDecl::Create(S.Context, Class, Loc,
DeclarationNameInfo(Name, Loc, NameLoc),
ConvTy,
S.Context.getTrivialTypeSourceInfo(ConvTy,
Loc),
/*isInline=*/false, /*isExplicit=*/false,
/*isConstexpr=*/false,
CallOperator->getBody()->getLocEnd());
Conversion->setAccess(AS_public);
Conversion->setImplicit(true);
Class->addDecl(Conversion);
// Add a non-static member function "__invoke" that will be the result of
// the conversion.
Name = &S.Context.Idents.get("__invoke");
CXXMethodDecl *Invoke
= CXXMethodDecl::Create(S.Context, Class, Loc,
DeclarationNameInfo(Name, Loc), FunctionTy,
CallOperator->getTypeSourceInfo(),
/*IsStatic=*/true, SC_Static, /*IsInline=*/true,
/*IsConstexpr=*/false,
CallOperator->getBody()->getLocEnd());
SmallVector<ParmVarDecl *, 4> InvokeParams;
for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
ParmVarDecl *From = CallOperator->getParamDecl(I);
InvokeParams.push_back(ParmVarDecl::Create(S.Context, Invoke,
From->getLocStart(),
From->getLocation(),
From->getIdentifier(),
From->getType(),
From->getTypeSourceInfo(),
From->getStorageClass(),
From->getStorageClassAsWritten(),
/*DefaultArg=*/0));
}
Invoke->setParams(InvokeParams);
Invoke->setAccess(AS_private);
Invoke->setImplicit(true);
Class->addDecl(Invoke);
}
/// \brief Add a lambda's conversion to block pointer.
static void addBlockPointerConversion(Sema &S,
SourceRange IntroducerRange,
CXXRecordDecl *Class,
CXXMethodDecl *CallOperator) {
const FunctionProtoType *Proto
= CallOperator->getType()->getAs<FunctionProtoType>();
QualType BlockPtrTy;
{
FunctionProtoType::ExtProtoInfo ExtInfo = Proto->getExtProtoInfo();
ExtInfo.TypeQuals = 0;
QualType FunctionTy
= S.Context.getFunctionType(Proto->getResultType(),
Proto->arg_type_begin(),
Proto->getNumArgs(),
ExtInfo);
BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
}
FunctionProtoType::ExtProtoInfo ExtInfo;
ExtInfo.TypeQuals = Qualifiers::Const;
QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, 0, 0, ExtInfo);
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=*/false, /*isExplicit=*/false,
/*isConstexpr=*/false,
CallOperator->getBody()->getLocEnd());
Conversion->setAccess(AS_public);
Conversion->setImplicit(true);
Class->addDecl(Conversion);
}
ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body,
Scope *CurScope,
llvm::Optional<unsigned> ManglingNumber,
Decl *ContextDecl,
bool IsInstantiation) {
// Leave the expression-evaluation context.
DiscardCleanupsInEvaluationContext();
PopExpressionEvaluationContext();
// Collect information from the lambda scope.
llvm::SmallVector<LambdaExpr::Capture, 4> Captures;
llvm::SmallVector<Expr *, 4> CaptureInits;
LambdaCaptureDefault CaptureDefault;
CXXRecordDecl *Class;
CXXMethodDecl *CallOperator;
SourceRange IntroducerRange;
bool ExplicitParams;
bool ExplicitResultType;
bool LambdaExprNeedsCleanups;
llvm::SmallVector<VarDecl *, 4> ArrayIndexVars;
llvm::SmallVector<unsigned, 4> ArrayIndexStarts;
{
LambdaScopeInfo *LSI = getCurLambda();
CallOperator = LSI->CallOperator;
Class = LSI->Lambda;
IntroducerRange = LSI->IntroducerRange;
ExplicitParams = LSI->ExplicitParams;
ExplicitResultType = !LSI->HasImplicitReturnType;
LambdaExprNeedsCleanups = LSI->ExprNeedsCleanups;
ArrayIndexVars.swap(LSI->ArrayIndexVars);
ArrayIndexStarts.swap(LSI->ArrayIndexStarts);
// Translate captures.
for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
LambdaScopeInfo::Capture From = LSI->Captures[I];
assert(!From.isBlockCapture() && "Cannot capture __block variables");
bool IsImplicit = I >= LSI->NumExplicitCaptures;
// Handle 'this' capture.
if (From.isThisCapture()) {
Captures.push_back(LambdaExpr::Capture(From.getLocation(),
IsImplicit,
LCK_This));
CaptureInits.push_back(new (Context) CXXThisExpr(From.getLocation(),
getCurrentThisType(),
/*isImplicit=*/true));
continue;
}
VarDecl *Var = From.getVariable();
LambdaCaptureKind Kind = From.isCopyCapture()? LCK_ByCopy : LCK_ByRef;
Captures.push_back(LambdaExpr::Capture(From.getLocation(), IsImplicit,
Kind, Var, From.getEllipsisLoc()));
CaptureInits.push_back(From.getCopyExpr());
}
switch (LSI->ImpCaptureStyle) {
case CapturingScopeInfo::ImpCap_None:
CaptureDefault = LCD_None;
break;
case CapturingScopeInfo::ImpCap_LambdaByval:
CaptureDefault = LCD_ByCopy;
break;
case CapturingScopeInfo::ImpCap_LambdaByref:
CaptureDefault = LCD_ByRef;
break;
case CapturingScopeInfo::ImpCap_Block:
llvm_unreachable("block capture in lambda");
break;
}
// C++11 [expr.prim.lambda]p4:
// If a lambda-expression does not include a
// trailing-return-type, it is as if the trailing-return-type
// denotes the following type:
// FIXME: Assumes current resolution to core issue 975.
if (LSI->HasImplicitReturnType) {
// - 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;
if (LSI->ReturnType.isNull()) {
LSI->ReturnType = Context.VoidTy;
} else {
// C++11 [expr.prim.lambda]p4:
// - if the compound-statement is of the form
//
// { attribute-specifier-seq[opt] return expression ; }
//
// the type of the returned expression after
// lvalue-to-rvalue conversion (4.1), array-to-pointer
// conver- sion (4.2), and function-to-pointer conversion
// (4.3);
//
// Since we're accepting the resolution to a post-C++11 core
// issue with a non-trivial extension, provide a warning (by
// default).
CompoundStmt *CompoundBody = cast<CompoundStmt>(Body);
if (!(CompoundBody->size() == 1 &&
isa<ReturnStmt>(*CompoundBody->body_begin())) &&
!Context.hasSameType(LSI->ReturnType, Context.VoidTy))
Diag(IntroducerRange.getBegin(),
diag::ext_lambda_implies_void_return);
}
// Create a function type with the inferred return type.
const FunctionProtoType *Proto
= CallOperator->getType()->getAs<FunctionProtoType>();
QualType FunctionTy
= Context.getFunctionType(LSI->ReturnType,
Proto->arg_type_begin(),
Proto->getNumArgs(),
Proto->getExtProtoInfo());
CallOperator->setType(FunctionTy);
}
// C++ [expr.prim.lambda]p7:
// The lambda-expression's compound-statement yields the
// function-body (8.4) of the function call operator [...].
ActOnFinishFunctionBody(CallOperator, Body, IsInstantiation);
CallOperator->setLexicalDeclContext(Class);
Class->addDecl(CallOperator);
// 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.
if (getLangOptions().Blocks)
addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator);
// Finalize the lambda class.
SmallVector<Decl*, 4> Fields(Class->field_begin(), Class->field_end());
ActOnFields(0, Class->getLocation(), Class, Fields,
SourceLocation(), SourceLocation(), 0);
CheckCompletedCXXClass(Class);
}
if (LambdaExprNeedsCleanups)
ExprNeedsCleanups = true;
// If we don't already have a mangling number for this lambda expression,
// allocate one now.
if (!ManglingNumber) {
ContextDecl = ExprEvalContexts.back().LambdaContextDecl;
// FIXME: Data member initializers.
enum ContextKind {
Normal,
DefaultArgument
} Kind = Normal;
// Default arguments of member function parameters that appear in a class
// definition receive special treatment. Identify them.
if (ParmVarDecl *Param = dyn_cast_or_null<ParmVarDecl>(ContextDecl)) {
if (const DeclContext *LexicalDC
= Param->getDeclContext()->getLexicalParent())
if (LexicalDC->isRecord())
Kind = DefaultArgument;
}
switch (Kind) {
case Normal:
ManglingNumber = Context.getLambdaManglingNumber(CallOperator);
ContextDecl = 0;
break;
case DefaultArgument:
ManglingNumber = ExprEvalContexts.back().getLambdaMangleContext()
.getManglingNumber(CallOperator);
break;
}
}
LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
CaptureDefault, Captures,
ExplicitParams, ExplicitResultType,
CaptureInits, ArrayIndexVars,
ArrayIndexStarts, Body->getLocEnd(),
*ManglingNumber, ContextDecl);
// C++11 [expr.prim.lambda]p2:
// A lambda-expression shall not appear in an unevaluated operand
// (Clause 5).
if (!CurContext->isDependentContext()) {
switch (ExprEvalContexts.back().Context) {
case Unevaluated:
// 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 ConstantEvaluated:
case PotentiallyEvaluated:
case PotentiallyEvaluatedIfUsed:
break;
}
}
return MaybeBindToTemporary(Lambda);
}
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