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//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
// 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++ expressions.
#include "SemaInherit.h"
#include "Sema.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ASTContext.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/STLExtras.h"
using namespace clang;
/// ActOnCXXConversionFunctionExpr - Parse a C++ conversion function
/// name (e.g., operator void const *) as an expression. This is
/// very similar to ActOnIdentifierExpr, except that instead of
/// providing an identifier the parser provides the type of the
/// conversion function.
Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc,
TypeTy *Ty, bool HasTrailingLParen,
const CXXScopeSpec &SS,
bool isAddressOfOperand) {
//FIXME: Preserve type source info.
QualType ConvType = GetTypeFromParser(Ty);
CanQualType ConvTypeCanon = Context.getCanonicalType(ConvType);
DeclarationName ConvName
= Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon);
return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen,
&SS, isAddressOfOperand);
/// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator
/// name (e.g., @c operator+ ) as an expression. This is very
/// similar to ActOnIdentifierExpr, except that instead of providing
/// an identifier the parser provides the kind of overloaded
/// operator that was parsed.
Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc,
OverloadedOperatorKind Op,
bool HasTrailingLParen,
const CXXScopeSpec &SS,
bool isAddressOfOperand) {
DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op);
return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS,
/// ActOnCXXTypeidOfType - Parse typeid( type-id ).
Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
NamespaceDecl *StdNs = GetStdNamespace();
if (!StdNs)
return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
if (isType)
// FIXME: Preserve type source info.
TyOrExpr = GetTypeFromParser(TyOrExpr).getAsOpaquePtr();
IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
Decl *TypeInfoDecl = LookupQualifiedName(StdNs, TypeInfoII, LookupTagName);
RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null<RecordDecl>(TypeInfoDecl);
if (!TypeInfoRecordDecl)
return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl);
if (!isType) {
// C++0x [expr.typeid]p3:
// When typeid is applied to an expression other than an lvalue of a
// polymorphic class type [...] [the] expression is an unevaluated
// operand.
// FIXME: if the type of the expression is a class type, the class
// shall be completely defined.
bool isUnevaluatedOperand = true;
Expr *E = static_cast<Expr *>(TyOrExpr);
if (E && !E->isTypeDependent() && E->isLvalue(Context) == Expr::LV_Valid) {
QualType T = E->getType();
if (const RecordType *RecordT = T->getAs<RecordType>()) {
CXXRecordDecl *RecordD = cast<CXXRecordDecl>(RecordT->getDecl());
if (RecordD->isPolymorphic())
isUnevaluatedOperand = false;
// If this is an unevaluated operand, clear out the set of declaration
// references we have been computing.
if (isUnevaluatedOperand)
return Owned(new (Context) CXXTypeidExpr(isType, TyOrExpr,
SourceRange(OpLoc, RParenLoc)));
/// ActOnCXXBoolLiteral - Parse {true,false} literals.
Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
"Unknown C++ Boolean value!");
return Owned(new (Context) CXXBoolLiteralExpr(Kind == tok::kw_true,
Context.BoolTy, OpLoc));
/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
Sema::ActOnCXXNullPtrLiteral(SourceLocation Loc) {
return Owned(new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc));
/// ActOnCXXThrow - Parse throw expressions.
Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprArg E) {
Expr *Ex = E.takeAs<Expr>();
if (Ex && !Ex->isTypeDependent() && CheckCXXThrowOperand(OpLoc, Ex))
return ExprError();
return Owned(new (Context) CXXThrowExpr(Ex, Context.VoidTy, OpLoc));
/// CheckCXXThrowOperand - Validate the operand of a throw.
bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) {
// C++ [except.throw]p3:
// [...] adjusting the type from "array of T" or "function returning T"
// to "pointer to T" or "pointer to function returning T", [...]
// If the type of the exception would be an incomplete type or a pointer
// to an incomplete type other than (cv) void the program is ill-formed.
QualType Ty = E->getType();
int isPointer = 0;
if (const PointerType* Ptr = Ty->getAs<PointerType>()) {
Ty = Ptr->getPointeeType();
isPointer = 1;
if (!isPointer || !Ty->isVoidType()) {
if (RequireCompleteType(ThrowLoc, Ty,
isPointer ? diag::err_throw_incomplete_ptr
: diag::err_throw_incomplete,
E->getSourceRange(), SourceRange(), QualType()))
return true;
// FIXME: Construct a temporary here.
return false;
Action::OwningExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) {
/// C++ 9.3.2: In the body of a non-static member function, the keyword this
/// is a non-lvalue expression whose value is the address of the object for
/// which the function is called.
if (!isa<FunctionDecl>(CurContext))
return ExprError(Diag(ThisLoc, diag::err_invalid_this_use));
if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext))
if (MD->isInstance())
return Owned(new (Context) CXXThisExpr(ThisLoc,
return ExprError(Diag(ThisLoc, diag::err_invalid_this_use));
/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep,
SourceLocation LParenLoc,
MultiExprArg exprs,
SourceLocation *CommaLocs,
SourceLocation RParenLoc) {
assert(TypeRep && "Missing type!");
// FIXME: Preserve type source info.
QualType Ty = GetTypeFromParser(TypeRep);
unsigned NumExprs = exprs.size();
Expr **Exprs = (Expr**)exprs.get();
SourceLocation TyBeginLoc = TypeRange.getBegin();
SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc);
if (Ty->isDependentType() ||
CallExpr::hasAnyTypeDependentArguments(Exprs, NumExprs)) {
return Owned(CXXUnresolvedConstructExpr::Create(Context,
TypeRange.getBegin(), Ty,
Exprs, NumExprs,
// C++ [expr.type.conv]p1:
// If the expression list is a single expression, the type conversion
// expression is equivalent (in definedness, and if defined in meaning) to the
// corresponding cast expression.
if (NumExprs == 1) {
CastExpr::CastKind Kind = CastExpr::CK_Unknown;
if (CheckCastTypes(TypeRange, Ty, Exprs[0], Kind, /*functional-style*/true))
return ExprError();
return Owned(new (Context) CXXFunctionalCastExpr(Ty.getNonReferenceType(),
Ty, TyBeginLoc, Kind,
Exprs[0], RParenLoc));
if (const RecordType *RT = Ty->getAs<RecordType>()) {
CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
// FIXME: We should always create a CXXTemporaryObjectExpr here unless
// both the ctor and dtor are trivial.
if (NumExprs > 1 || Record->hasUserDeclaredConstructor()) {
CXXConstructorDecl *Constructor
= PerformInitializationByConstructor(Ty, Exprs, NumExprs,
if (!Constructor)
return ExprError();
Expr *E = new (Context) CXXTemporaryObjectExpr(Context, Constructor,
Ty, TyBeginLoc, Exprs,
NumExprs, RParenLoc);
return MaybeBindToTemporary(E);
// Fall through to value-initialize an object of class type that
// doesn't have a user-declared default constructor.
// C++ [expr.type.conv]p1:
// If the expression list specifies more than a single value, the type shall
// be a class with a suitably declared constructor.
if (NumExprs > 1)
return ExprError(Diag(CommaLocs[0],
<< FullRange);
assert(NumExprs == 0 && "Expected 0 expressions");
// C++ [expr.type.conv]p2:
// The expression T(), where T is a simple-type-specifier for a non-array
// complete object type or the (possibly cv-qualified) void type, creates an
// rvalue of the specified type, which is value-initialized.
if (Ty->isArrayType())
return ExprError(Diag(TyBeginLoc,
diag::err_value_init_for_array_type) << FullRange);
if (!Ty->isDependentType() && !Ty->isVoidType() &&
RequireCompleteType(TyBeginLoc, Ty,
diag::err_invalid_incomplete_type_use, FullRange))
return ExprError();
if (RequireNonAbstractType(TyBeginLoc, Ty,
return ExprError();
return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc));
/// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.:
/// @code new (memory) int[size][4] @endcode
/// or
/// @code ::new Foo(23, "hello") @endcode
/// For the interpretation of this heap of arguments, consult the base version.
Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
SourceLocation PlacementLParen, MultiExprArg PlacementArgs,
SourceLocation PlacementRParen, bool ParenTypeId,
Declarator &D, SourceLocation ConstructorLParen,
MultiExprArg ConstructorArgs,
SourceLocation ConstructorRParen)
Expr *ArraySize = 0;
unsigned Skip = 0;
// If the specified type is an array, unwrap it and save the expression.
if (D.getNumTypeObjects() > 0 &&
D.getTypeObject(0).Kind == DeclaratorChunk::Array) {
DeclaratorChunk &Chunk = D.getTypeObject(0);
if (Chunk.Arr.hasStatic)
return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new)
<< D.getSourceRange());
if (!Chunk.Arr.NumElts)
return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size)
<< D.getSourceRange());
ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts);
Skip = 1;
//FIXME: Store DeclaratorInfo in CXXNew expression.
DeclaratorInfo *DInfo = 0;
QualType AllocType = GetTypeForDeclarator(D, /*Scope=*/0, &DInfo, Skip);
if (D.isInvalidType())
return ExprError();
// Every dimension shall be of constant size.
unsigned i = 1;
QualType ElementType = AllocType;
while (const ArrayType *Array = Context.getAsArrayType(ElementType)) {
if (!Array->isConstantArrayType()) {
Diag(D.getTypeObject(i).Loc, diag::err_new_array_nonconst)
<< static_cast<Expr*>(D.getTypeObject(i).Arr.NumElts)->getSourceRange();
return ExprError();
ElementType = Array->getElementType();
return BuildCXXNew(StartLoc, UseGlobal,
Sema::BuildCXXNew(SourceLocation StartLoc, bool UseGlobal,
SourceLocation PlacementLParen,
MultiExprArg PlacementArgs,
SourceLocation PlacementRParen,
bool ParenTypeId,
QualType AllocType,
SourceLocation TypeLoc,
SourceRange TypeRange,
ExprArg ArraySizeE,
SourceLocation ConstructorLParen,
MultiExprArg ConstructorArgs,
SourceLocation ConstructorRParen) {
if (CheckAllocatedType(AllocType, TypeLoc, TypeRange))
return ExprError();
QualType ResultType = Context.getPointerType(AllocType);
// That every array dimension except the first is constant was already
// checked by the type check above.
// C++ 5.3.4p6: "The expression in a direct-new-declarator shall have integral
// or enumeration type with a non-negative value."
Expr *ArraySize = (Expr *)ArraySizeE.get();
if (ArraySize && !ArraySize->isTypeDependent()) {
QualType SizeType = ArraySize->getType();
if (!SizeType->isIntegralType() && !SizeType->isEnumeralType())
return ExprError(Diag(ArraySize->getSourceRange().getBegin(),
<< SizeType << ArraySize->getSourceRange());
// Let's see if this is a constant < 0. If so, we reject it out of hand.
// We don't care about special rules, so we tell the machinery it's not
// evaluated - it gives us a result in more cases.
if (!ArraySize->isValueDependent()) {
llvm::APSInt Value;
if (ArraySize->isIntegerConstantExpr(Value, Context, 0, false)) {
if (Value < llvm::APSInt(
llvm::APInt::getNullValue(Value.getBitWidth()), false))
return ExprError(Diag(ArraySize->getSourceRange().getBegin(),
<< ArraySize->getSourceRange());
FunctionDecl *OperatorNew = 0;
FunctionDecl *OperatorDelete = 0;
Expr **PlaceArgs = (Expr**)PlacementArgs.get();
unsigned NumPlaceArgs = PlacementArgs.size();
if (!AllocType->isDependentType() &&
!Expr::hasAnyTypeDependentArguments(PlaceArgs, NumPlaceArgs) &&
SourceRange(PlacementLParen, PlacementRParen),
UseGlobal, AllocType, ArraySize, PlaceArgs,
NumPlaceArgs, OperatorNew, OperatorDelete))
return ExprError();
bool Init = ConstructorLParen.isValid();
// --- Choosing a constructor ---
// C++ 5.3.4p15
// 1) If T is a POD and there's no initializer (ConstructorLParen is invalid)
// the object is not initialized. If the object, or any part of it, is
// const-qualified, it's an error.
// 2) If T is a POD and there's an empty initializer, the object is value-
// initialized.
// 3) If T is a POD and there's one initializer argument, the object is copy-
// constructed.
// 4) If T is a POD and there's more initializer arguments, it's an error.
// 5) If T is not a POD, the initializer arguments are used as constructor
// arguments.
// Or by the C++0x formulation:
// 1) If there's no initializer, the object is default-initialized according
// to C++0x rules.
// 2) Otherwise, the object is direct-initialized.
CXXConstructorDecl *Constructor = 0;
Expr **ConsArgs = (Expr**)ConstructorArgs.get();
const RecordType *RT;
unsigned NumConsArgs = ConstructorArgs.size();
if (AllocType->isDependentType()) {
// Skip all the checks.
} else if ((RT = AllocType->getAs<RecordType>()) &&
!AllocType->isAggregateType()) {
Constructor = PerformInitializationByConstructor(
AllocType, ConsArgs, NumConsArgs,
SourceRange(TypeLoc, ConstructorRParen),
NumConsArgs != 0 ? IK_Direct : IK_Default);
if (!Constructor)
return ExprError();
} else {
if (!Init) {
// FIXME: Check that no subpart is const.
if (AllocType.isConstQualified())
return ExprError(Diag(StartLoc, diag::err_new_uninitialized_const)
<< TypeRange);
} else if (NumConsArgs == 0) {
// Object is value-initialized. Do nothing.
} else if (NumConsArgs == 1) {
// Object is direct-initialized.
// FIXME: What DeclarationName do we pass in here?
if (CheckInitializerTypes(ConsArgs[0], AllocType, StartLoc,
DeclarationName() /*AllocType.getAsString()*/,
return ExprError();
} else {
return ExprError(Diag(StartLoc,
<< SourceRange(ConstructorLParen, ConstructorRParen));
// FIXME: Also check that the destructor is accessible. (C++ 5.3.4p16)
return Owned(new (Context) CXXNewExpr(UseGlobal, OperatorNew, PlaceArgs,
NumPlaceArgs, ParenTypeId, ArraySize, Constructor, Init,
ConsArgs, NumConsArgs, OperatorDelete, ResultType,
StartLoc, Init ? ConstructorRParen : SourceLocation()));
/// CheckAllocatedType - Checks that a type is suitable as the allocated type
/// in a new-expression.
/// dimension off and stores the size expression in ArraySize.
bool Sema::CheckAllocatedType(QualType AllocType, SourceLocation Loc,
SourceRange R)
// C++ 5.3.4p1: "[The] type shall be a complete object type, but not an
// abstract class type or array thereof.
if (AllocType->isFunctionType())
return Diag(Loc, diag::err_bad_new_type)
<< AllocType << 0 << R;
else if (AllocType->isReferenceType())
return Diag(Loc, diag::err_bad_new_type)
<< AllocType << 1 << R;
else if (!AllocType->isDependentType() &&
RequireCompleteType(Loc, AllocType,
return true;
else if (RequireNonAbstractType(Loc, AllocType,
return true;
return false;
/// FindAllocationFunctions - Finds the overloads of operator new and delete
/// that are appropriate for the allocation.
bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
bool UseGlobal, QualType AllocType,
bool IsArray, Expr **PlaceArgs,
unsigned NumPlaceArgs,
FunctionDecl *&OperatorNew,
FunctionDecl *&OperatorDelete)
// --- Choosing an allocation function ---
// C++ 5.3.4p8 - 14 & 18
// 1) If UseGlobal is true, only look in the global scope. Else, also look
// in the scope of the allocated class.
// 2) If an array size is given, look for operator new[], else look for
// operator new.
// 3) The first argument is always size_t. Append the arguments from the
// placement form.
// FIXME: Also find the appropriate delete operator.
llvm::SmallVector<Expr*, 8> AllocArgs(1 + NumPlaceArgs);
// We don't care about the actual value of this argument.
// FIXME: Should the Sema create the expression and embed it in the syntax
// tree? Or should the consumer just recalculate the value?
IntegerLiteral Size(llvm::APInt::getNullValue(
AllocArgs[0] = &Size;
std::copy(PlaceArgs, PlaceArgs + NumPlaceArgs, AllocArgs.begin() + 1);
DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName(
IsArray ? OO_Array_New : OO_New);
if (AllocType->isRecordType() && !UseGlobal) {
CXXRecordDecl *Record
= cast<CXXRecordDecl>(AllocType->getAs<RecordType>()->getDecl());
// FIXME: We fail to find inherited overloads.
if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
AllocArgs.size(), Record, /*AllowMissing=*/true,
return true;
if (!OperatorNew) {
// Didn't find a member overload. Look for a global one.
DeclContext *TUDecl = Context.getTranslationUnitDecl();
if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0],
AllocArgs.size(), TUDecl, /*AllowMissing=*/false,
return true;
// FindAllocationOverload can change the passed in arguments, so we need to
// copy them back.
if (NumPlaceArgs > 0)
std::copy(&AllocArgs[1], AllocArgs.end(), PlaceArgs);
return false;
/// FindAllocationOverload - Find an fitting overload for the allocation
/// function in the specified scope.
bool Sema::FindAllocationOverload(SourceLocation StartLoc, SourceRange Range,
DeclarationName Name, Expr** Args,
unsigned NumArgs, DeclContext *Ctx,
bool AllowMissing, FunctionDecl *&Operator)
DeclContext::lookup_iterator Alloc, AllocEnd;
llvm::tie(Alloc, AllocEnd) = Ctx->lookup(Name);
if (Alloc == AllocEnd) {
if (AllowMissing)
return false;
return Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
<< Name << Range;
OverloadCandidateSet Candidates;
for (; Alloc != AllocEnd; ++Alloc) {
// Even member operator new/delete are implicitly treated as
// static, so don't use AddMemberCandidate.
if (FunctionDecl *Fn = dyn_cast<FunctionDecl>(*Alloc))
AddOverloadCandidate(Fn, Args, NumArgs, Candidates,
// Do the resolution.
OverloadCandidateSet::iterator Best;
switch(BestViableFunction(Candidates, StartLoc, Best)) {
case OR_Success: {
// Got one!
FunctionDecl *FnDecl = Best->Function;
// The first argument is size_t, and the first parameter must be size_t,
// too. This is checked on declaration and can be assumed. (It can't be
// asserted on, though, since invalid decls are left in there.)
for (unsigned i = 1; i < NumArgs; ++i) {
// FIXME: Passing word to diagnostic.
if (PerformCopyInitialization(Args[i],
return true;
Operator = FnDecl;
return false;
case OR_No_Viable_Function:
Diag(StartLoc, diag::err_ovl_no_viable_function_in_call)
<< Name << Range;
PrintOverloadCandidates(Candidates, /*OnlyViable=*/false);
return true;
case OR_Ambiguous:
Diag(StartLoc, diag::err_ovl_ambiguous_call)
<< Name << Range;
PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
return true;
case OR_Deleted:
Diag(StartLoc, diag::err_ovl_deleted_call)
<< Best->Function->isDeleted()
<< Name << Range;
PrintOverloadCandidates(Candidates, /*OnlyViable=*/true);
return true;
assert(false && "Unreachable, bad result from BestViableFunction");
return true;
/// DeclareGlobalNewDelete - Declare the global forms of operator new and
/// delete. These are:
/// @code
/// void* operator new(std::size_t) throw(std::bad_alloc);
/// void* operator new[](std::size_t) throw(std::bad_alloc);
/// void operator delete(void *) throw();
/// void operator delete[](void *) throw();
/// @endcode
/// Note that the placement and nothrow forms of new are *not* implicitly
/// declared. Their use requires including \<new\>.
void Sema::DeclareGlobalNewDelete()
if (GlobalNewDeleteDeclared)
GlobalNewDeleteDeclared = true;
QualType VoidPtr = Context.getPointerType(Context.VoidTy);
QualType SizeT = Context.getSizeType();
// FIXME: Exception specifications are not added.
VoidPtr, SizeT);
VoidPtr, SizeT);
Context.VoidTy, VoidPtr);
Context.VoidTy, VoidPtr);
/// DeclareGlobalAllocationFunction - Declares a single implicit global
/// allocation function if it doesn't already exist.
void Sema::DeclareGlobalAllocationFunction(DeclarationName Name,
QualType Return, QualType Argument)
DeclContext *GlobalCtx = Context.getTranslationUnitDecl();
// Check if this function is already declared.
DeclContext::lookup_iterator Alloc, AllocEnd;
for (llvm::tie(Alloc, AllocEnd) = GlobalCtx->lookup(Name);
Alloc != AllocEnd; ++Alloc) {
// FIXME: Do we need to check for default arguments here?
FunctionDecl *Func = cast<FunctionDecl>(*Alloc);
if (Func->getNumParams() == 1 &&
QualType FnType = Context.getFunctionType(Return, &Argument, 1, false, 0);
FunctionDecl *Alloc =
FunctionDecl::Create(Context, GlobalCtx, SourceLocation(), Name,
FnType, /*DInfo=*/0, FunctionDecl::None, false, true);
ParmVarDecl *Param = ParmVarDecl::Create(Context, Alloc, SourceLocation(),
0, Argument, /*DInfo=*/0,
VarDecl::None, 0);
Alloc->setParams(Context, &Param, 1);
// FIXME: Also add this declaration to the IdentifierResolver, but
// make sure it is at the end of the chain to coincide with the
// global scope.
((DeclContext *)TUScope->getEntity())->addDecl(Alloc);
/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
/// @code ::delete ptr; @endcode
/// or
/// @code delete [] ptr; @endcode
Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
bool ArrayForm, ExprArg Operand)
// C++ 5.3.5p1: "The operand shall have a pointer type, or a class type
// having a single conversion function to a pointer type. The result has
// type void."
// DR599 amends "pointer type" to "pointer to object type" in both cases.
FunctionDecl *OperatorDelete = 0;
Expr *Ex = (Expr *)Operand.get();
if (!Ex->isTypeDependent()) {
QualType Type = Ex->getType();
if (Type->isRecordType()) {
// FIXME: Find that one conversion function and amend the type.
if (!Type->isPointerType())
return ExprError(Diag(StartLoc, diag::err_delete_operand)
<< Type << Ex->getSourceRange());
QualType Pointee = Type->getAs<PointerType>()->getPointeeType();
if (Pointee->isFunctionType() || Pointee->isVoidType())
return ExprError(Diag(StartLoc, diag::err_delete_operand)
<< Type << Ex->getSourceRange());
else if (!Pointee->isDependentType() &&
RequireCompleteType(StartLoc, Pointee,
return ExprError();
// FIXME: This should be shared with the code for finding the delete
// operator in ActOnCXXNew.
IntegerLiteral Size(llvm::APInt::getNullValue(
ImplicitCastExpr Cast(Context.getPointerType(Context.VoidTy),
CastExpr::CK_Unknown, &Size, false);
Expr *DeleteArg = &Cast;
DeclarationName DeleteName = Context.DeclarationNames.getCXXOperatorName(
ArrayForm ? OO_Array_Delete : OO_Delete);
if (Pointee->isRecordType() && !UseGlobal) {
CXXRecordDecl *Record
= cast<CXXRecordDecl>(Pointee->getAs<RecordType>()->getDecl());
// FIXME: We fail to find inherited overloads.
if (FindAllocationOverload(StartLoc, SourceRange(), DeleteName,
&DeleteArg, 1, Record, /*AllowMissing=*/true,
return ExprError();
if (!OperatorDelete) {
// Didn't find a member overload. Look for a global one.
DeclContext *TUDecl = Context.getTranslationUnitDecl();
if (FindAllocationOverload(StartLoc, SourceRange(), DeleteName,
&DeleteArg, 1, TUDecl, /*AllowMissing=*/false,
return ExprError();
// FIXME: Check access and ambiguity of operator delete and destructor.
return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm,
OperatorDelete, Ex, StartLoc));
/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
/// C++ if/switch/while/for statement.
/// e.g: "if (int x = f()) {...}"
Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc,
Declarator &D,
SourceLocation EqualLoc,
ExprArg AssignExprVal) {
assert(AssignExprVal.get() && "Null assignment expression");
// C++ 6.4p2:
// The declarator shall not specify a function or an array.
// The type-specifier-seq shall not contain typedef and shall not declare a
// new class or enumeration.
assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
"Parser allowed 'typedef' as storage class of condition decl.");
// FIXME: Store DeclaratorInfo in the expression.
DeclaratorInfo *DInfo = 0;
TagDecl *OwnedTag = 0;
QualType Ty = GetTypeForDeclarator(D, S, &DInfo, /*Skip=*/0, &OwnedTag);
if (Ty->isFunctionType()) { // The declarator shall not specify a function...
// We exit without creating a CXXConditionDeclExpr because a FunctionDecl
// would be created and CXXConditionDeclExpr wants a VarDecl.
return ExprError(Diag(StartLoc, diag::err_invalid_use_of_function_type)
<< SourceRange(StartLoc, EqualLoc));
} else if (Ty->isArrayType()) { // ...or an array.
Diag(StartLoc, diag::err_invalid_use_of_array_type)
<< SourceRange(StartLoc, EqualLoc);
} else if (OwnedTag && OwnedTag->isDefinition()) {
// The type-specifier-seq shall not declare a new class or enumeration.
Diag(OwnedTag->getLocation(), diag::err_type_defined_in_condition);
DeclPtrTy Dcl = ActOnDeclarator(S, D);
if (!Dcl)
return ExprError();
AddInitializerToDecl(Dcl, move(AssignExprVal), /*DirectInit=*/false);
// Mark this variable as one that is declared within a conditional.
// We know that the decl had to be a VarDecl because that is the only type of
// decl that can be assigned and the grammar requires an '='.
VarDecl *VD = cast<VarDecl>(Dcl.getAs<Decl>());
return Owned(new (Context) CXXConditionDeclExpr(StartLoc, EqualLoc, VD));
/// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
bool Sema::CheckCXXBooleanCondition(Expr *&CondExpr) {
// C++ 6.4p4:
// The value of a condition that is an initialized declaration in a statement
// other than a switch statement is the value of the declared variable
// implicitly converted to type bool. If that conversion is ill-formed, the
// program is ill-formed.
// The value of a condition that is an expression is the value of the
// expression, implicitly converted to bool.
return PerformContextuallyConvertToBool(CondExpr);
/// Helper function to determine whether this is the (deprecated) C++
/// conversion from a string literal to a pointer to non-const char or
/// non-const wchar_t (for narrow and wide string literals,
/// respectively).
Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
// Look inside the implicit cast, if it exists.
if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
From = Cast->getSubExpr();
// A string literal (2.13.4) that is not a wide string literal can
// be converted to an rvalue of type "pointer to char"; a wide
// string literal can be converted to an rvalue of type "pointer
// to wchar_t" (C++ 4.2p2).
if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From))
if (const PointerType *ToPtrType = ToType->getAs<PointerType>())
if (const BuiltinType *ToPointeeType
= ToPtrType->getPointeeType()->getAsBuiltinType()) {
// This conversion is considered only when there is an
// explicit appropriate pointer target type (C++ 4.2p2).
if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 &&
((StrLit->isWide() && ToPointeeType->isWideCharType()) ||
(!StrLit->isWide() &&
(ToPointeeType->getKind() == BuiltinType::Char_U ||
ToPointeeType->getKind() == BuiltinType::Char_S))))
return true;
return false;
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType. Returns true if there was an
/// error, false otherwise. The expression From is replaced with the
/// converted expression. Flavor is the kind of conversion we're
/// performing, used in the error message. If @p AllowExplicit,
/// explicit user-defined conversions are permitted. @p Elidable should be true
/// when called for copies which may be elided (C++ 12.8p15). C++0x overload
/// resolution works differently in that case.
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
const char *Flavor, bool AllowExplicit,
bool Elidable)
ImplicitConversionSequence ICS;
ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
if (Elidable && getLangOptions().CPlusPlus0x) {
ICS = TryImplicitConversion(From, ToType, /*SuppressUserConversions*/false,
AllowExplicit, /*ForceRValue*/true);
if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) {
ICS = TryImplicitConversion(From, ToType, false, AllowExplicit);
return PerformImplicitConversion(From, ToType, ICS, Flavor);
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType using the pre-computed implicit
/// conversion sequence ICS. Returns true if there was an error, false
/// otherwise. The expression From is replaced with the converted
/// expression. Flavor is the kind of conversion we're performing,
/// used in the error message.
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
const ImplicitConversionSequence &ICS,
const char* Flavor) {
switch (ICS.ConversionKind) {
case ImplicitConversionSequence::StandardConversion:
if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor))
return true;
case ImplicitConversionSequence::UserDefinedConversion:
// FIXME: This is, of course, wrong. We'll need to actually call the
// constructor or conversion operator, and then cope with the standard
// conversions.
ImpCastExprToType(From, ToType.getNonReferenceType(),
return false;
case ImplicitConversionSequence::EllipsisConversion:
assert(false && "Cannot perform an ellipsis conversion");
return false;
case ImplicitConversionSequence::BadConversion:
return true;
// Everything went well.
return false;
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType by following the standard
/// conversion sequence SCS. Returns true if there was an error, false
/// otherwise. The expression From is replaced with the converted
/// expression. Flavor is the context in which we're performing this
/// conversion, for use in error messages.
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
const StandardConversionSequence& SCS,
const char *Flavor) {
// Overall FIXME: we are recomputing too many types here and doing far too
// much extra work. What this means is that we need to keep track of more
// information that is computed when we try the implicit conversion initially,
// so that we don't need to recompute anything here.
QualType FromType = From->getType();
if (SCS.CopyConstructor) {
// FIXME: When can ToType be a reference type?
From = BuildCXXConstructExpr(ToType, SCS.CopyConstructor, &From, 1);
return false;
// Perform the first implicit conversion.
switch (SCS.First) {
case ICK_Identity:
case ICK_Lvalue_To_Rvalue:
// Nothing to do.
case ICK_Array_To_Pointer:
FromType = Context.getArrayDecayedType(FromType);
ImpCastExprToType(From, FromType, CastExpr::CK_ArrayToPointerDecay);
case ICK_Function_To_Pointer:
if (Context.getCanonicalType(FromType) == Context.OverloadTy) {
FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true);
if (!Fn)
return true;
if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin()))
return true;
FixOverloadedFunctionReference(From, Fn);
FromType = From->getType();
FromType = Context.getPointerType(FromType);
ImpCastExprToType(From, FromType);
assert(false && "Improper first standard conversion");
// Perform the second implicit conversion
switch (SCS.Second) {
case ICK_Identity:
// Nothing to do.
case ICK_Integral_Promotion:
case ICK_Floating_Promotion:
case ICK_Complex_Promotion:
case ICK_Integral_Conversion:
case ICK_Floating_Conversion:
case ICK_Complex_Conversion:
case ICK_Floating_Integral:
case ICK_Complex_Real:
case ICK_Compatible_Conversion:
// FIXME: Go deeper to get the unqualified type!
FromType = ToType.getUnqualifiedType();
ImpCastExprToType(From, FromType);
case ICK_Pointer_Conversion:
if (SCS.IncompatibleObjC) {
// Diagnose incompatible Objective-C conversions
<< From->getType() << ToType << Flavor
<< From->getSourceRange();
if (CheckPointerConversion(From, ToType))
return true;
ImpCastExprToType(From, ToType);
case ICK_Pointer_Member:
if (CheckMemberPointerConversion(From, ToType))
return true;
ImpCastExprToType(From, ToType);
case ICK_Boolean_Conversion:
FromType = Context.BoolTy;
ImpCastExprToType(From, FromType);
assert(false && "Improper second standard conversion");
switch (SCS.Third) {
case ICK_Identity:
// Nothing to do.
case ICK_Qualification:
// FIXME: Not sure about lvalue vs rvalue here in the presence of rvalue
// references.
ImpCastExprToType(From, ToType.getNonReferenceType(),
assert(false && "Improper second standard conversion");
return false;
Sema::OwningExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
SourceLocation KWLoc,
SourceLocation LParen,
TypeTy *Ty,
SourceLocation RParen) {
QualType T = GetTypeFromParser(Ty);
// According to
// all traits except __is_class, __is_enum and __is_union require a the type
// to be complete.
if (OTT != UTT_IsClass && OTT != UTT_IsEnum && OTT != UTT_IsUnion) {
if (RequireCompleteType(KWLoc, T,
SourceRange(), SourceRange(), T))
return ExprError();
// There is no point in eagerly computing the value. The traits are designed
// to be used from type trait templates, so Ty will be a template parameter
// 99% of the time.
return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT, T,
RParen, Context.BoolTy));
QualType Sema::CheckPointerToMemberOperands(
Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect)
const char *OpSpelling = isIndirect ? "->*" : ".*";
// C++ 5.5p2
// The binary operator .* [p3: ->*] binds its second operand, which shall
// be of type "pointer to member of T" (where T is a completely-defined
// class type) [...]
QualType RType = rex->getType();
const MemberPointerType *MemPtr = RType->getAs<MemberPointerType>();
if (!MemPtr) {
Diag(Loc, diag::err_bad_memptr_rhs)
<< OpSpelling << RType << rex->getSourceRange();
return QualType();
QualType Class(MemPtr->getClass(), 0);
// C++ 5.5p2
// [...] to its first operand, which shall be of class T or of a class of
// which T is an unambiguous and accessible base class. [p3: a pointer to
// such a class]
QualType LType = lex->getType();
if (isIndirect) {
if (const PointerType *Ptr = LType->getAs<PointerType>())
LType = Ptr->getPointeeType().getNonReferenceType();
else {
Diag(Loc, diag::err_bad_memptr_lhs)
<< OpSpelling << 1 << LType << lex->getSourceRange();
return QualType();
if (Context.getCanonicalType(Class).getUnqualifiedType() !=
Context.getCanonicalType(LType).getUnqualifiedType()) {
BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
// FIXME: Would it be useful to print full ambiguity paths, or is that
// overkill?
if (!IsDerivedFrom(LType, Class, Paths) ||
Paths.isAmbiguous(Context.getCanonicalType(Class))) {
Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
<< (int)isIndirect << lex->getType() << lex->getSourceRange();
return QualType();
// C++ 5.5p2
// The result is an object or a function of the type specified by the
// second operand.
// The cv qualifiers are the union of those in the pointer and the left side,
// in accordance with 5.5p5 and 5.2.5.
// FIXME: This returns a dereferenced member function pointer as a normal
// function type. However, the only operation valid on such functions is
// calling them. There's also a GCC extension to get a function pointer to the
// thing, which is another complication, because this type - unlike the type
// that is the result of this expression - takes the class as the first
// argument.
// We probably need a "MemberFunctionClosureType" or something like that.
QualType Result = MemPtr->getPointeeType();
if (LType.isConstQualified())
if (LType.isVolatileQualified())
return Result;
/// \brief Get the target type of a standard or user-defined conversion.
static QualType TargetType(const ImplicitConversionSequence &ICS) {
assert((ICS.ConversionKind ==
ImplicitConversionSequence::StandardConversion ||
ICS.ConversionKind ==
ImplicitConversionSequence::UserDefinedConversion) &&
"function only valid for standard or user-defined conversions");
if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion)
return QualType::getFromOpaquePtr(ICS.Standard.ToTypePtr);
return QualType::getFromOpaquePtr(ICS.UserDefined.After.ToTypePtr);
/// \brief Try to convert a type to another according to C++0x 5.16p3.
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, the two operands are attempted to be
/// converted to each other. This function does the conversion in one direction.
/// It emits a diagnostic and returns true only if it finds an ambiguous
/// conversion.
static bool TryClassUnification(Sema &Self, Expr *From, Expr *To,
SourceLocation QuestionLoc,
ImplicitConversionSequence &ICS)
// C++0x 5.16p3
// The process for determining whether an operand expression E1 of type T1
// can be converted to match an operand expression E2 of type T2 is defined
// as follows:
// -- If E2 is an lvalue:
if (To->isLvalue(Self.Context) == Expr::LV_Valid) {
// E1 can be converted to match E2 if E1 can be implicitly converted to
// type "lvalue reference to T2", subject to the constraint that in the
// conversion the reference must bind directly to E1.
if (!Self.CheckReferenceInit(From,
assert((ICS.ConversionKind ==
ImplicitConversionSequence::StandardConversion ||
ICS.ConversionKind ==
ImplicitConversionSequence::UserDefinedConversion) &&
"expected a definite conversion");
bool DirectBinding =
ICS.ConversionKind == ImplicitConversionSequence::StandardConversion ?
ICS.Standard.DirectBinding : ICS.UserDefined.After.DirectBinding;
if (DirectBinding)
return false;
ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
// -- If E2 is an rvalue, or if the conversion above cannot be done:
// -- if E1 and E2 have class type, and the underlying class types are
// the same or one is a base class of the other:
QualType FTy = From->getType();
QualType TTy = To->getType();
const RecordType *FRec = FTy->getAs<RecordType>();
const RecordType *TRec = TTy->getAs<RecordType>();
bool FDerivedFromT = FRec && TRec && Self.IsDerivedFrom(FTy, TTy);
if (FRec && TRec && (FRec == TRec ||
FDerivedFromT || Self.IsDerivedFrom(TTy, FTy))) {
// E1 can be converted to match E2 if the class of T2 is the
// same type as, or a base class of, the class of T1, and
// [cv2 > cv1].
if ((FRec == TRec || FDerivedFromT) && TTy.isAtLeastAsQualifiedAs(FTy)) {
// Could still fail if there's no copy constructor.
// FIXME: Is this a hard error then, or just a conversion failure? The
// standard doesn't say.
ICS = Self.TryCopyInitialization(From, TTy);
} else {
// -- Otherwise: E1 can be converted to match E2 if E1 can be
// implicitly converted to the type that expression E2 would have
// if E2 were converted to an rvalue.
// First find the decayed type.
if (TTy->isFunctionType())
TTy = Self.Context.getPointerType(TTy);
else if(TTy->isArrayType())
TTy = Self.Context.getArrayDecayedType(TTy);
// Now try the implicit conversion.
// FIXME: This doesn't detect ambiguities.
ICS = Self.TryImplicitConversion(From, TTy);
return false;
/// \brief Try to find a common type for two according to C++0x 5.16p5.
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, overload resolution is used to find a
/// conversion to a common type.
static bool FindConditionalOverload(Sema &Self, Expr *&LHS, Expr *&RHS,
SourceLocation Loc) {
Expr *Args[2] = { LHS, RHS };
OverloadCandidateSet CandidateSet;
Self.AddBuiltinOperatorCandidates(OO_Conditional, Args, 2, CandidateSet);
OverloadCandidateSet::iterator Best;
switch (Self.BestViableFunction(CandidateSet, Loc, Best)) {
case Sema::OR_Success:
// We found a match. Perform the conversions on the arguments and move on.
if (Self.PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0],
Best->Conversions[0], "converting") ||
Self.PerformImplicitConversion(RHS, Best->BuiltinTypes.ParamTypes[1],
Best->Conversions[1], "converting"))
return false;
case Sema::OR_No_Viable_Function:
Self.Diag(Loc, diag::err_typecheck_cond_incompatible_operands)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange();
return true;
case Sema::OR_Ambiguous:
Self.Diag(Loc, diag::err_conditional_ambiguous_ovl)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange();
// FIXME: Print the possible common types by printing the return types of
// the viable candidates.
case Sema::OR_Deleted:
assert(false && "Conditional operator has only built-in overloads");
return true;
/// \brief Perform an "extended" implicit conversion as returned by
/// TryClassUnification.
/// TryClassUnification generates ICSs that include reference bindings.
/// PerformImplicitConversion is not suitable for this; it chokes if the
/// second part of a standard conversion is ICK_DerivedToBase. This function
/// handles the reference binding specially.
static bool ConvertForConditional(Sema &Self, Expr *&E,
const ImplicitConversionSequence &ICS)
if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion &&
ICS.Standard.ReferenceBinding) {
assert(ICS.Standard.DirectBinding &&
"TryClassUnification should never generate indirect ref bindings");
// FIXME: CheckReferenceInit should be able to reuse the ICS instead of
// redoing all the work.
return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType(
if (ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion &&
ICS.UserDefined.After.ReferenceBinding) {
assert(ICS.UserDefined.After.DirectBinding &&
"TryClassUnification should never generate indirect ref bindings");
return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType(
if (Self.PerformImplicitConversion(E, TargetType(ICS), ICS, "converting"))
return true;
return false;
/// \brief Check the operands of ?: under C++ semantics.
/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y
/// extension. In this case, LHS == Cond. (But they're not aliases.)
QualType Sema::CXXCheckConditionalOperands(Expr *&Cond, Expr *&LHS, Expr *&RHS,
SourceLocation QuestionLoc) {
// FIXME: Handle C99's complex types, vector types, block pointers and Obj-C++
// interface pointers.
// C++0x 5.16p1
// The first expression is contextually converted to bool.
if (!Cond->isTypeDependent()) {
if (CheckCXXBooleanCondition(Cond))
return QualType();
// Either of the arguments dependent?
if (LHS->isTypeDependent() || RHS->isTypeDependent())
return Context.DependentTy;
// C++0x 5.16p2
// If either the second or the third operand has type (cv) void, ...
QualType LTy = LHS->getType();
QualType RTy = RHS->getType();
bool LVoid = LTy->isVoidType();
bool RVoid = RTy->isVoidType();
if (LVoid || RVoid) {
// ... then the [l2r] conversions are performed on the second and third
// operands ...
LTy = LHS->getType();
RTy = RHS->getType();
// ... and one of the following shall hold:
// -- The second or the third operand (but not both) is a throw-
// expression; the result is of the type of the other and is an rvalue.
bool LThrow = isa<CXXThrowExpr>(LHS);
bool RThrow = isa<CXXThrowExpr>(RHS);
if (LThrow && !RThrow)
return RTy;
if (RThrow && !LThrow)
return LTy;
// -- Both the second and third operands have type void; the result is of
// type void and is an rvalue.
if (LVoid && RVoid)
return Context.VoidTy;
// Neither holds, error.
Diag(QuestionLoc, diag::err_conditional_void_nonvoid)
<< (LVoid ? RTy : LTy) << (LVoid ? 0 : 1)
<< LHS->getSourceRange() << RHS->getSourceRange();
return QualType();
// Neither is void.
// C++0x 5.16p3
// Otherwise, if the second and third operand have different types, and
// either has (cv) class type, and attempt is made to convert each of those
// operands to the other.
if (Context.getCanonicalType(LTy) != Context.getCanonicalType(RTy) &&
(LTy->isRecordType() || RTy->isRecordType())) {
ImplicitConversionSequence ICSLeftToRight, ICSRightToLeft;
// These return true if a single direction is already ambiguous.
if (TryClassUnification(*this, LHS, RHS, QuestionLoc, ICSLeftToRight))
return QualType();
if (TryClassUnification(*this, RHS, LHS, QuestionLoc, ICSRightToLeft))
return QualType();
bool HaveL2R = ICSLeftToRight.ConversionKind !=
bool HaveR2L = ICSRightToLeft.ConversionKind !=
// If both can be converted, [...] the program is ill-formed.
if (HaveL2R && HaveR2L) {
Diag(QuestionLoc, diag::err_conditional_ambiguous)
<< LTy << RTy << LHS->getSourceRange() << RHS->getSourceRange();
return QualType();
// If exactly one conversion is possible, that conversion is applied to
// the chosen operand and the converted operands are used in place of the
// original operands for the remainder of this section.
if (HaveL2R) {
if (ConvertForConditional(*this, LHS, ICSLeftToRight))
return QualType();
LTy = LHS->getType();
} else if (HaveR2L) {
if (ConvertForConditional(*this, RHS, ICSRightToLeft))
return QualType();
RTy = RHS->getType();
// C++0x 5.16p4
// If the second and third operands are lvalues and have the same type,
// the result is of that type [...]
bool Same = Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy);
if (Same && LHS->isLvalue(Context) == Expr::LV_Valid &&
RHS->isLvalue(Context) == Expr::LV_Valid)
return LTy;
// C++0x 5.16p5
// Otherwise, the result is an rvalue. If the second and third operands
// do not have the same type, and either has (cv) class type, ...
if (!Same && (LTy->isRecordType() || RTy->isRecordType())) {
// ... overload resolution is used to determine the conversions (if any)
// to be applied to the operands. If the overload resolution fails, the
// program is ill-formed.
if (FindConditionalOverload(*this, LHS, RHS, QuestionLoc))
return QualType();
// C++0x 5.16p6
// LValue-to-rvalue, array-to-pointer, and function-to-pointer standard
// conversions are performed on the second and third operands.
LTy = LHS->getType();
RTy = RHS->getType();
// After those conversions, one of the following shall hold:
// -- The second and third operands have the same type; the result
// is of that type.
if (Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy))
return LTy;
// -- The second and third operands have arithmetic or enumeration type;
// the usual arithmetic conversions are performed to bring them to a
// common type, and the result is of that type.
if (LTy->isArithmeticType() && RTy->isArithmeticType()) {
UsualArithmeticConversions(LHS, RHS);
return LHS->getType();
// -- The second and third operands have pointer type, or one has pointer
// type and the other is a null pointer constant; pointer conversions
// and qualification conversions are performed to bring them to their
// composite pointer type. The result is of the composite pointer type.
QualType Composite = FindCompositePointerType(LHS, RHS);
if (!Composite.isNull())
return Composite;
// Fourth bullet is same for pointers-to-member. However, the possible
// conversions are far more limited: we have null-to-pointer, upcast of
// containing class, and second-level cv-ness.
// cv-ness is not a union, but must match one of the two operands. (Which,
// frankly, is stupid.)
const MemberPointerType *LMemPtr = LTy->getAs<MemberPointerType>();
const MemberPointerType *RMemPtr = RTy->getAs<MemberPointerType>();
if (LMemPtr && RHS->isNullPointerConstant(Context)) {
ImpCastExprToType(RHS, LTy);
return LTy;
if (RMemPtr && LHS->isNullPointerConstant(Context)) {
ImpCastExprToType(LHS, RTy);
return RTy;
if (LMemPtr && RMemPtr) {
QualType LPointee = LMemPtr->getPointeeType();
QualType RPointee = RMemPtr->getPointeeType();
// First, we check that the unqualified pointee type is the same. If it's
// not, there's no conversion that will unify the two pointers.
if (Context.getCanonicalType(LPointee).getUnqualifiedType() ==
Context.getCanonicalType(RPointee).getUnqualifiedType()) {
// Second, we take the greater of the two cv qualifications. If neither
// is greater than the other, the conversion is not possible.
unsigned Q = LPointee.getCVRQualifiers() | RPointee.getCVRQualifiers();
if (Q == LPointee.getCVRQualifiers() || Q == RPointee.getCVRQualifiers()){
// Third, we check if either of the container classes is derived from
// the other.
QualType LContainer(LMemPtr->getClass(), 0);
QualType RContainer(RMemPtr->getClass(), 0);
QualType MoreDerived;
if (Context.getCanonicalType(LContainer) ==
MoreDerived = LContainer;
else if (IsDerivedFrom(LContainer, RContainer))
MoreDerived = LContainer;
else if (IsDerivedFrom(RContainer, LContainer))
MoreDerived = RContainer;
if (!MoreDerived.isNull()) {
// The type 'Q Pointee (MoreDerived::*)' is the common type.
// We don't use ImpCastExprToType here because this could still fail
// for ambiguous or inaccessible conversions.
QualType Common = Context.getMemberPointerType(
LPointee.getQualifiedType(Q), MoreDerived.getTypePtr());
if (PerformImplicitConversion(LHS, Common, "converting"))
return QualType();
if (PerformImplicitConversion(RHS, Common, "converting"))
return QualType();
return Common;
Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange();
return QualType();
/// \brief Find a merged pointer type and convert the two expressions to it.
/// This finds the composite pointer type for @p E1 and @p E2 according to
/// C++0x 5.9p2. It converts both expressions to this type and returns it.
/// It does not emit diagnostics.
QualType Sema::FindCompositePointerType(Expr *&E1, Expr *&E2) {
assert(getLangOptions().CPlusPlus && "This function assumes C++");
QualType T1 = E1->getType(), T2 = E2->getType();
if(!T1->isAnyPointerType() && !T2->isAnyPointerType())
return QualType();
// C++0x 5.9p2
// Pointer conversions and qualification conversions are performed on
// pointer operands to bring them to their composite pointer type. If
// one operand is a null pointer constant, the composite pointer type is
// the type of the other operand.
if (E1->isNullPointerConstant(Context)) {
ImpCastExprToType(E1, T2);
return T2;
if (E2->isNullPointerConstant(Context)) {
ImpCastExprToType(E2, T1);
return T1;
// Now both have to be pointers.
if(!T1->isPointerType() || !T2->isPointerType())
return QualType();
// Otherwise, of one of the operands has type "pointer to cv1 void," then
// the other has type "pointer to cv2 T" and the composite pointer type is
// "pointer to cv12 void," where cv12 is the union of cv1 and cv2.
// Otherwise, the composite pointer type is a pointer type similar to the
// type of one of the operands, with a cv-qualification signature that is
// the union of the cv-qualification signatures of the operand types.
// In practice, the first part here is redundant; it's subsumed by the second.
// What we do here is, we build the two possible composite types, and try the
// conversions in both directions. If only one works, or if the two composite
// types are the same, we have succeeded.
llvm::SmallVector<unsigned, 4> QualifierUnion;
QualType Composite1 = T1, Composite2 = T2;
const PointerType *Ptr1, *Ptr2;
while ((Ptr1 = Composite1->getAs<PointerType>()) &&
(Ptr2 = Composite2->getAs<PointerType>())) {
Composite1 = Ptr1->getPointeeType();
Composite2 = Ptr2->getPointeeType();
Composite1.getCVRQualifiers() | Composite2.getCVRQualifiers());
// Rewrap the composites as pointers with the union CVRs.
for (llvm::SmallVector<unsigned, 4>::iterator I = QualifierUnion.begin(),
E = QualifierUnion.end(); I != E; ++I) {
Composite1 = Context.getPointerType(Composite1.getQualifiedType(*I));
Composite2 = Context.getPointerType(Composite2.getQualifiedType(*I));
ImplicitConversionSequence E1ToC1 = TryImplicitConversion(E1, Composite1);
ImplicitConversionSequence E2ToC1 = TryImplicitConversion(E2, Composite1);
ImplicitConversionSequence E1ToC2, E2ToC2;
E1ToC2.ConversionKind = ImplicitConversionSequence::BadConversion;
E2ToC2.ConversionKind = ImplicitConversionSequence::BadConversion;
if (Context.getCanonicalType(Composite1) !=
Context.getCanonicalType(Composite2)) {
E1ToC2 = TryImplicitConversion(E1, Composite2);
E2ToC2 = TryImplicitConversion(E2, Composite2);
bool ToC1Viable = E1ToC1.ConversionKind !=
&& E2ToC1.ConversionKind !=
bool ToC2Viable = E1ToC2.ConversionKind !=
&& E2ToC2.ConversionKind !=
if (ToC1Viable && !ToC2Viable) {
if (!PerformImplicitConversion(E1, Composite1, E1ToC1, "converting") &&
!PerformImplicitConversion(E2, Composite1, E2ToC1, "converting"))
return Composite1;
if (ToC2Viable && !ToC1Viable) {
if (!PerformImplicitConversion(E1, Composite2, E1ToC2, "converting") &&
!PerformImplicitConversion(E2, Composite2, E2ToC2, "converting"))
return Composite2;
return QualType();
Sema::OwningExprResult Sema::MaybeBindToTemporary(Expr *E) {
if (!Context.getLangOptions().CPlusPlus)
return Owned(E);
const RecordType *RT = E->getType()->getAs<RecordType>();
if (!RT)
return Owned(E);
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->hasTrivialDestructor())
return Owned(E);
CXXTemporary *Temp = CXXTemporary::Create(Context,
if (CXXDestructorDecl *Destructor =
MarkDeclarationReferenced(E->getExprLoc(), Destructor);
// FIXME: Add the temporary to the temporaries vector.
return Owned(CXXBindTemporaryExpr::Create(Context, Temp, E));
Expr *Sema::MaybeCreateCXXExprWithTemporaries(Expr *SubExpr,
bool ShouldDestroyTemps) {
assert(SubExpr && "sub expression can't be null!");
if (ExprTemporaries.empty())
return SubExpr;
Expr *E = CXXExprWithTemporaries::Create(Context, SubExpr,
return E;
Sema::OwningExprResult Sema::ActOnFinishFullExpr(ExprArg Arg) {
Expr *FullExpr = Arg.takeAs<Expr>();
if (FullExpr)
FullExpr = MaybeCreateCXXExprWithTemporaries(FullExpr,
return Owned(FullExpr);