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minix/external/bsd/llvm/dist/clang/lib/Sema/SemaLambda.cpp
Lionel Sambuc f4a2713ac8 Importing netbsd clang -- pristine 
Change-Id: Ia40e9ffdf29b5dab2f122f673ff6802a58bc690f
2014-07-28 17:05:57 +02:00

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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/AST/ASTLambda.h"
#include "clang/AST/ExprCXX.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.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"
#include "TypeLocBuilder.h"
using namespace clang;
using namespace sema;
// returns -1 if none of the lambdas on the scope stack can capture.
// A lambda 'L' is capture-ready for a certain variable 'V' if,
// - its enclosing context is non-dependent
// - and if the chain of lambdas between L and the lambda in which
// V is potentially used, call all capture or have captured V.
static inline int GetScopeIndexOfNearestCaptureReadyLambda(
ArrayRef<clang::sema::FunctionScopeInfo*> FunctionScopes,
DeclContext *const CurContext, VarDecl *VD) {
DeclContext *EnclosingDC = CurContext;
// If VD is null, we are attempting to capture 'this'
const bool IsCapturingThis = !VD;
const bool IsCapturingVariable = !IsCapturingThis;
int RetIndex = -1;
unsigned CurScopeIndex = FunctionScopes.size() - 1;
while (!EnclosingDC->isTranslationUnit() &&
EnclosingDC->isDependentContext() && isLambdaCallOperator(EnclosingDC)) {
RetIndex = CurScopeIndex;
clang::sema::LambdaScopeInfo *LSI =
cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]);
// We have crawled up to an intervening lambda that contains the
// variable declaration - so not only does it not need to capture;
// none of the enclosing lambdas need to capture it, and since all
// other nested lambdas are dependent (otherwise we wouldn't have
// arrived here) - we don't yet have a lambda that can capture the
// variable.
if (IsCapturingVariable && VD->getDeclContext()->Equals(EnclosingDC))
return -1;
// All intervening lambda call operators have to be able to capture.
// 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(VD))
return -1;
if (IsCapturingThis && !LSI->isCXXThisCaptured())
return -1;
}
EnclosingDC = getLambdaAwareParentOfDeclContext(EnclosingDC);
--CurScopeIndex;
}
// If the enclosingDC is not dependent, then the immediately nested lambda
// is capture-ready.
if (!EnclosingDC->isDependentContext())
return RetIndex;
return -1;
}
// Given a lambda's call operator and a variable (or null for 'this'),
// compute the nearest enclosing lambda that is capture-ready (i.e
// the enclosing context is not dependent, and all intervening lambdas can
// either implicitly or explicitly capture Var)
//
// The approach is as follows, for the entity VD ('this' if null):
// - start with the current lambda
// - if it is non-dependent and can capture VD, return it.
// - if it is dependent and has an implicit or explicit capture, check its parent
// whether the parent is non-depdendent and all its intervening lambdas
// can capture, if so return the child.
// [Note: When we hit a generic lambda specialization, do not climb up
// the scope stack any further since not only do we not need to,
// the scope stack will often not be synchronized with any lambdas
// enclosing the specialized generic lambda]
//
// Return the CallOperator of the capturable lambda and set function scope
// index to the correct index within the function scope stack to correspond
// to the capturable lambda.
// If VarDecl *VD is null, we check for 'this' capture.
CXXMethodDecl* clang::GetInnermostEnclosingCapturableLambda(
ArrayRef<sema::FunctionScopeInfo*> FunctionScopes,
unsigned &FunctionScopeIndex,
DeclContext *const CurContext, VarDecl *VD,
Sema &S) {
const int IndexOfCaptureReadyLambda =
GetScopeIndexOfNearestCaptureReadyLambda(FunctionScopes,CurContext, VD);
if (IndexOfCaptureReadyLambda == -1) return 0;
assert(IndexOfCaptureReadyLambda >= 0);
const unsigned IndexOfCaptureReadyLambdaU =
static_cast<unsigned>(IndexOfCaptureReadyLambda);
sema::LambdaScopeInfo *const CaptureReadyLambdaLSI =
cast<sema::LambdaScopeInfo>(FunctionScopes[IndexOfCaptureReadyLambdaU]);
// If VD is null, we are attempting to capture 'this'
const bool IsCapturingThis = !VD;
const bool IsCapturingVariable = !IsCapturingThis;
if (IsCapturingVariable) {
// Now check to see if this lambda can truly capture, and also
// if all enclosing lambdas of this lambda allow this capture.
QualType CaptureType, DeclRefType;
const bool CanCaptureVariable = !S.tryCaptureVariable(VD,
/*ExprVarIsUsedInLoc*/SourceLocation(), clang::Sema::TryCapture_Implicit,
/*EllipsisLoc*/ SourceLocation(),
/*BuildAndDiagnose*/false, CaptureType, DeclRefType,
&IndexOfCaptureReadyLambdaU);
if (!CanCaptureVariable) return 0;
} else {
const bool CanCaptureThis = !S.CheckCXXThisCapture(
CaptureReadyLambdaLSI->PotentialThisCaptureLocation, false, false,
&IndexOfCaptureReadyLambdaU);
if (!CanCaptureThis) return 0;
} // end 'this' capture test
FunctionScopeIndex = IndexOfCaptureReadyLambdaU;
return CaptureReadyLambdaLSI->CallOperator;
}
static inline TemplateParameterList *
getGenericLambdaTemplateParameterList(LambdaScopeInfo *LSI, Sema &SemaRef) {
if (LSI->GLTemplateParameterList)
return LSI->GLTemplateParameterList;
if (LSI->AutoTemplateParams.size()) {
SourceRange IntroRange = LSI->IntroducerRange;
SourceLocation LAngleLoc = IntroRange.getBegin();
SourceLocation RAngleLoc = IntroRange.getEnd();
LSI->GLTemplateParameterList = TemplateParameterList::Create(
SemaRef.Context,
/*Template kw loc*/SourceLocation(),
LAngleLoc,
(NamedDecl**)LSI->AutoTemplateParams.data(),
LSI->AutoTemplateParams.size(), RAngleLoc);
}
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;
}
/// \brief 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
} 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 (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 =
!ActiveTemplateInstantiations.empty() || 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 = 0;
return &Context.getManglingNumberContext(DC);
}
ManglingContextDecl = 0;
return 0;
case StaticDataMember:
// -- the initializers of nonspecialized static members of template classes
if (!IsInNonspecializedTemplate) {
ManglingContextDecl = 0;
return 0;
}
// Fall through to get the current context.
case DataMember:
// -- the in-class initializers of class members
case DefaultArgument:
// -- default arguments appearing in class definitions
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) {
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->getResultType();
if (Result->isUndeducedType()) {
Result = SubstAutoType(Result, Context.DependentTy);
MethodType = Context.getFunctionType(Result, FPT->getArgTypes(),
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,
/*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);
// Create a function template if we have a template parameter list
FunctionTemplateDecl *const TemplateMethod = TemplateParams ?
FunctionTemplateDecl::Create(Context, Class,
Method->getLocation(), MethodName,
TemplateParams,
Method) : 0;
if (TemplateMethod) {
TemplateMethod->setLexicalDeclContext(CurContext);
TemplateMethod->setAccess(AS_public);
Method->setDescribedFunctionTemplate(TemplateMethod);
}
// 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);
}
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->getResultType();
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 0;
}
// - 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 0;
}
// - 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 0;
}
// - 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 0;
}
// (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 0;
}
/// 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 0;
}
/// 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 0;
// Check that the rest of the returns have the same enum.
for (++i; i != e; ++i) {
if (findEnumForBlockReturn(*i) != ED)
return 0;
}
// Never infer an anonymous enum type.
if (!ED->hasNameForLinkage()) return 0;
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*/ 0, 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());
// C++ Core Issue #975, proposed resolution:
// 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.
//
// 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!
SmallVectorImpl<ReturnStmt*>::iterator I = CSI.Returns.begin(),
E = CSI.Returns.end();
if (I+1 == E)
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 (; I != E; ++I) {
const ReturnStmt *RS = *I;
const Expr *RetE = RS->getRetValue();
QualType ReturnType = (RetE ? RetE->getType() : Context.VoidTy);
if (Context.hasSameType(ReturnType, CSI.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.
}
}
VarDecl *Sema::checkInitCapture(SourceLocation Loc, bool ByRef,
IdentifierInfo *Id, Expr *Init) {
// C++1y [expr.prim.lambda]p11:
// An init-capture behaves as if it declares and explicitly captures
// a variable of the form
// "auto init-capture;"
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);
// 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, TSI->getType(), TSI, SC_Auto);
NewVD->setInitCapture(true);
NewVD->setReferenced(true);
NewVD->markUsed(Context);
// We do not need to distinguish between direct-list-initialization
// and copy-list-initialization here, because we will always deduce
// std::initializer_list<T>, and direct- and copy-list-initialization
// always behave the same for such a type.
// FIXME: We should model whether an '=' was present.
bool DirectInit = isa<ParenListExpr>(Init) || isa<InitListExpr>(Init);
AddInitializerToDecl(NewVD, Init, DirectInit, /*ContainsAuto*/true);
return NewVD;
}
FieldDecl *Sema::buildInitCaptureField(LambdaScopeInfo *LSI, VarDecl *Var) {
FieldDecl *Field = FieldDecl::Create(
Context, LSI->Lambda, Var->getLocation(), Var->getLocation(),
0, Var->getType(), Var->getTypeSourceInfo(), 0, 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!");
TemplateParameterList *TemplateParams =
getGenericLambdaTemplateParameterList(LSI, *this);
if (Scope *TmplScope = CurScope->getTemplateParamParent()) {
// Since we have our own TemplateParams, so check if an outer scope
// has template params, only then are we in a dependent scope.
if (TemplateParams) {
TmplScope = TmplScope->getParent();
TmplScope = TmplScope ? TmplScope->getTemplateParamParent() : 0;
}
if (TmplScope && !TmplScope->decl_empty())
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().CPlusPlus1y ? 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 (FTI.NumArgs == 1 && !FTI.isVariadic && FTI.ArgInfo[0].Ident == 0 &&
cast<ParmVarDecl>(FTI.ArgInfo[0].Param)->getType()->isVoidType()) {
// Empty arg list, don't push any params.
checkVoidParamDecl(cast<ParmVarDecl>(FTI.ArgInfo[0].Param));
} else {
Params.reserve(FTI.NumArgs);
for (unsigned i = 0, e = FTI.NumArgs; i != e; ++i)
Params.push_back(cast<ParmVarDecl>(FTI.ArgInfo[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);
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);
// Build the lambda scope.
buildLambdaScope(LSI, Method,
Intro.Range,
Intro.Default, Intro.DefaultLoc,
ExplicitParams,
ExplicitResultType,
!Method->isConst());
// 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 (SmallVectorImpl<LambdaCapture>::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");
if (C->Init.isInvalid())
continue;
VarDecl *Var;
if (C->Init.isUsable()) {
Diag(C->Loc, getLangOpts().CPlusPlus1y
? diag::warn_cxx11_compat_init_capture
: diag::ext_init_capture);
if (C->Init.get()->containsUnexpandedParameterPack())
ContainsUnexpandedParameterPack = true;
Var = checkInitCapture(C->Loc, C->Kind == LCK_ByRef,
C->Id, C->Init.take());
// 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 {
// 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;
}
// 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;
DeclFilterCCC<VarDecl> Validator;
if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R, Validator))
continue;
}
Var = R.getAsSingle<VarDecl>();
}
// 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)) {
if (Var && 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));
} 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);
}
}
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(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;
for (RecordDecl::field_iterator i = Class->field_begin(),
e = Class->field_end(); i != e; ++i)
Fields.push_back(*i);
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 *CallOpProto =
CallOperator->getType()->getAs<FunctionProtoType>();
const FunctionProtoType::ExtProtoInfo CallOpExtInfo =
CallOpProto->getExtProtoInfo();
QualType PtrToFunctionTy;
QualType InvokerFunctionTy;
{
FunctionProtoType::ExtProtoInfo InvokerExtInfo = CallOpExtInfo;
CallingConv CC = S.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");
InvokerFunctionTy = S.Context.getFunctionType(CallOpProto->getResultType(),
CallOpProto->getArgTypes(), InvokerExtInfo);
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.getResultLoc().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=*/0));
CallOpConvTL.setArg(I, From);
CallOpConvNameTL.setArg(I, From);
}
CXXConversionDecl *Conversion
= CXXConversionDecl::Create(S.Context, Class, Loc,
DeclarationNameInfo(ConversionName,
Loc, ConvNameLoc),
ConvTy,
ConvTSI,
/*isInline=*/true, /*isExplicit=*/false,
/*isConstexpr=*/false,
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);
}
/// \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->getArgTypes(), ExtInfo);
BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
}
FunctionProtoType::ExtProtoInfo ExtInfo(S.Context.getDefaultCallingConvention(
/*IsVariadic=*/false, /*IsCXXMethod=*/true));
ExtInfo.TypeQuals = Qualifiers::Const;
QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, None, 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=*/true, /*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,
bool IsInstantiation) {
// Collect information from the lambda scope.
SmallVector<LambdaExpr::Capture, 4> Captures;
SmallVector<Expr *, 4> CaptureInits;
LambdaCaptureDefault CaptureDefault;
SourceLocation CaptureDefaultLoc;
CXXRecordDecl *Class;
CXXMethodDecl *CallOperator;
SourceRange IntroducerRange;
bool ExplicitParams;
bool ExplicitResultType;
bool LambdaExprNeedsCleanups;
bool ContainsUnexpandedParameterPack;
SmallVector<VarDecl *, 4> ArrayIndexVars;
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;
ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack;
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.getInitExpr());
}
switch (LSI->ImpCaptureStyle) {
case CapturingScopeInfo::ImpCap_None:
CaptureDefault = LCD_None;
break;
case CapturingScopeInfo::ImpCap_LambdaByval:
CaptureDefault = LCD_ByCopy;
break;
case CapturingScopeInfo::ImpCap_CapturedRegion:
case CapturingScopeInfo::ImpCap_LambdaByref:
CaptureDefault = LCD_ByRef;
break;
case CapturingScopeInfo::ImpCap_Block:
llvm_unreachable("block capture in lambda");
break;
}
CaptureDefaultLoc = LSI->CaptureDefaultLoc;
// 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:
//
// Skip for C++1y return type deduction semantics which uses
// different machinery.
// FIXME: Refactor and Merge the return type deduction machinery.
// FIXME: Assumes current resolution to core issue 975.
if (LSI->HasImplicitReturnType && !getLangOpts().CPlusPlus1y) {
deduceClosureReturnType(*LSI);
// - 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;
}
// Create a function type with the inferred return type.
const FunctionProtoType *Proto
= CallOperator->getType()->getAs<FunctionProtoType>();
QualType FunctionTy = Context.getFunctionType(
LSI->ReturnType, Proto->getArgTypes(), 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);
Decl *TemplateOrNonTemplateCallOperatorDecl =
CallOperator->getDescribedFunctionTemplate()
? CallOperator->getDescribedFunctionTemplate()
: cast<Decl>(CallOperator);
TemplateOrNonTemplateCallOperatorDecl->setLexicalDeclContext(Class);
Class->addDecl(TemplateOrNonTemplateCallOperatorDecl);
PopExpressionEvaluationContext();
// 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 &&
!Class->isGenericLambda())
addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator);
// Finalize the lambda class.
SmallVector<Decl*, 4> Fields;
for (RecordDecl::field_iterator i = Class->field_begin(),
e = Class->field_end(); i != e; ++i)
Fields.push_back(*i);
ActOnFields(0, Class->getLocation(), Class, Fields,
SourceLocation(), SourceLocation(), 0);
CheckCompletedCXXClass(Class);
}
if (LambdaExprNeedsCleanups)
ExprNeedsCleanups = true;
LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
CaptureDefault, CaptureDefaultLoc,
Captures,
ExplicitParams, ExplicitResultType,
CaptureInits, ArrayIndexVars,
ArrayIndexStarts, Body->getLocEnd(),
ContainsUnexpandedParameterPack);
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 Unevaluated:
case 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 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 PotentiallyEvaluated:
case 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::InitializeBlock(ConvLocation,
Src->getType(),
/*NRVO=*/false),
CurrentLocation, Src);
if (!Init.isInvalid())
Init = ActOnFinishFullExpr(Init.take());
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=*/0));
}
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, 0,
Src->getType(), CapVarTSI,
SC_None);
BlockDecl::Capture Capture(/*Variable=*/CapVar, /*ByRef=*/false,
/*Nested=*/false, /*Copy=*/Init.take());
Block->setCaptures(Context, &Capture, &Capture + 1,
/*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);
ExprNeedsCleanups = true;
return BuildBlock;
}
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