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//===--- SemaOverload.cpp - C++ Overloading ---------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides Sema routines for C++ overloading.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "SemaInherit.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/TypeOrdering.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
namespace clang {
/// GetConversionCategory - Retrieve the implicit conversion
/// category corresponding to the given implicit conversion kind.
ImplicitConversionCategory
GetConversionCategory(ImplicitConversionKind Kind) {
static const ImplicitConversionCategory
Category[(int)ICK_Num_Conversion_Kinds] = {
ICC_Identity,
ICC_Lvalue_Transformation,
ICC_Lvalue_Transformation,
ICC_Lvalue_Transformation,
ICC_Qualification_Adjustment,
ICC_Promotion,
ICC_Promotion,
ICC_Promotion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion,
ICC_Conversion
};
return Category[(int)Kind];
}
/// GetConversionRank - Retrieve the implicit conversion rank
/// corresponding to the given implicit conversion kind.
ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) {
static const ImplicitConversionRank
Rank[(int)ICK_Num_Conversion_Kinds] = {
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Exact_Match,
ICR_Promotion,
ICR_Promotion,
ICR_Promotion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion,
ICR_Conversion
};
return Rank[(int)Kind];
}
/// GetImplicitConversionName - Return the name of this kind of
/// implicit conversion.
const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
static const char* Name[(int)ICK_Num_Conversion_Kinds] = {
"No conversion",
"Lvalue-to-rvalue",
"Array-to-pointer",
"Function-to-pointer",
"Qualification",
"Integral promotion",
"Floating point promotion",
"Complex promotion",
"Integral conversion",
"Floating conversion",
"Complex conversion",
"Floating-integral conversion",
"Complex-real conversion",
"Pointer conversion",
"Pointer-to-member conversion",
"Boolean conversion",
"Compatible-types conversion",
"Derived-to-base conversion"
};
return Name[Kind];
}
/// StandardConversionSequence - Set the standard conversion
/// sequence to the identity conversion.
void StandardConversionSequence::setAsIdentityConversion() {
First = ICK_Identity;
Second = ICK_Identity;
Third = ICK_Identity;
Deprecated = false;
ReferenceBinding = false;
DirectBinding = false;
RRefBinding = false;
CopyConstructor = 0;
}
/// getRank - Retrieve the rank of this standard conversion sequence
/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
/// implicit conversions.
ImplicitConversionRank StandardConversionSequence::getRank() const {
ImplicitConversionRank Rank = ICR_Exact_Match;
if (GetConversionRank(First) > Rank)
Rank = GetConversionRank(First);
if (GetConversionRank(Second) > Rank)
Rank = GetConversionRank(Second);
if (GetConversionRank(Third) > Rank)
Rank = GetConversionRank(Third);
return Rank;
}
/// isPointerConversionToBool - Determines whether this conversion is
/// a conversion of a pointer or pointer-to-member to bool. This is
/// used as part of the ranking of standard conversion sequences
/// (C++ 13.3.3.2p4).
bool StandardConversionSequence::isPointerConversionToBool() const
{
QualType FromType = QualType::getFromOpaquePtr(FromTypePtr);
QualType ToType = QualType::getFromOpaquePtr(ToTypePtr);
// Note that FromType has not necessarily been transformed by the
// array-to-pointer or function-to-pointer implicit conversions, so
// check for their presence as well as checking whether FromType is
// a pointer.
if (ToType->isBooleanType() &&
(FromType->isPointerType() || FromType->isBlockPointerType() ||
First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
return true;
return false;
}
/// isPointerConversionToVoidPointer - Determines whether this
/// conversion is a conversion of a pointer to a void pointer. This is
/// used as part of the ranking of standard conversion sequences (C++
/// 13.3.3.2p4).
bool
StandardConversionSequence::
isPointerConversionToVoidPointer(ASTContext& Context) const
{
QualType FromType = QualType::getFromOpaquePtr(FromTypePtr);
QualType ToType = QualType::getFromOpaquePtr(ToTypePtr);
// Note that FromType has not necessarily been transformed by the
// array-to-pointer implicit conversion, so check for its presence
// and redo the conversion to get a pointer.
if (First == ICK_Array_To_Pointer)
FromType = Context.getArrayDecayedType(FromType);
if (Second == ICK_Pointer_Conversion)
if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
return ToPtrType->getPointeeType()->isVoidType();
return false;
}
/// DebugPrint - Print this standard conversion sequence to standard
/// error. Useful for debugging overloading issues.
void StandardConversionSequence::DebugPrint() const {
bool PrintedSomething = false;
if (First != ICK_Identity) {
fprintf(stderr, "%s", GetImplicitConversionName(First));
PrintedSomething = true;
}
if (Second != ICK_Identity) {
if (PrintedSomething) {
fprintf(stderr, " -> ");
}
fprintf(stderr, "%s", GetImplicitConversionName(Second));
if (CopyConstructor) {
fprintf(stderr, " (by copy constructor)");
} else if (DirectBinding) {
fprintf(stderr, " (direct reference binding)");
} else if (ReferenceBinding) {
fprintf(stderr, " (reference binding)");
}
PrintedSomething = true;
}
if (Third != ICK_Identity) {
if (PrintedSomething) {
fprintf(stderr, " -> ");
}
fprintf(stderr, "%s", GetImplicitConversionName(Third));
PrintedSomething = true;
}
if (!PrintedSomething) {
fprintf(stderr, "No conversions required");
}
}
/// DebugPrint - Print this user-defined conversion sequence to standard
/// error. Useful for debugging overloading issues.
void UserDefinedConversionSequence::DebugPrint() const {
if (Before.First || Before.Second || Before.Third) {
Before.DebugPrint();
fprintf(stderr, " -> ");
}
fprintf(stderr, "'%s'", ConversionFunction->getNameAsString().c_str());
if (After.First || After.Second || After.Third) {
fprintf(stderr, " -> ");
After.DebugPrint();
}
}
/// DebugPrint - Print this implicit conversion sequence to standard
/// error. Useful for debugging overloading issues.
void ImplicitConversionSequence::DebugPrint() const {
switch (ConversionKind) {
case StandardConversion:
fprintf(stderr, "Standard conversion: ");
Standard.DebugPrint();
break;
case UserDefinedConversion:
fprintf(stderr, "User-defined conversion: ");
UserDefined.DebugPrint();
break;
case EllipsisConversion:
fprintf(stderr, "Ellipsis conversion");
break;
case BadConversion:
fprintf(stderr, "Bad conversion");
break;
}
fprintf(stderr, "\n");
}
// IsOverload - Determine whether the given New declaration is an
// overload of the Old declaration. This routine returns false if New
// and Old cannot be overloaded, e.g., if they are functions with the
// same signature (C++ 1.3.10) or if the Old declaration isn't a
// function (or overload set). When it does return false and Old is an
// OverloadedFunctionDecl, MatchedDecl will be set to point to the
// FunctionDecl that New cannot be overloaded with.
//
// Example: Given the following input:
//
// void f(int, float); // #1
// void f(int, int); // #2
// int f(int, int); // #3
//
// When we process #1, there is no previous declaration of "f",
// so IsOverload will not be used.
//
// When we process #2, Old is a FunctionDecl for #1. By comparing the
// parameter types, we see that #1 and #2 are overloaded (since they
// have different signatures), so this routine returns false;
// MatchedDecl is unchanged.
//
// When we process #3, Old is an OverloadedFunctionDecl containing #1
// and #2. We compare the signatures of #3 to #1 (they're overloaded,
// so we do nothing) and then #3 to #2. Since the signatures of #3 and
// #2 are identical (return types of functions are not part of the
// signature), IsOverload returns false and MatchedDecl will be set to
// point to the FunctionDecl for #2.
bool
Sema::IsOverload(FunctionDecl *New, Decl* OldD,
OverloadedFunctionDecl::function_iterator& MatchedDecl)
{
if (OverloadedFunctionDecl* Ovl = dyn_cast<OverloadedFunctionDecl>(OldD)) {
// Is this new function an overload of every function in the
// overload set?
OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(),
FuncEnd = Ovl->function_end();
for (; Func != FuncEnd; ++Func) {
if (!IsOverload(New, *Func, MatchedDecl)) {
MatchedDecl = Func;
return false;
}
}
// This function overloads every function in the overload set.
return true;
} else if (FunctionTemplateDecl *Old = dyn_cast<FunctionTemplateDecl>(OldD))
return IsOverload(New, Old->getTemplatedDecl(), MatchedDecl);
else if (FunctionDecl* Old = dyn_cast<FunctionDecl>(OldD)) {
FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
// C++ [temp.fct]p2:
// A function template can be overloaded with other function templates
// and with normal (non-template) functions.
if ((OldTemplate == 0) != (NewTemplate == 0))
return true;
// Is the function New an overload of the function Old?
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());
// Compare the signatures (C++ 1.3.10) of the two functions to
// determine whether they are overloads. If we find any mismatch
// in the signature, they are overloads.
// If either of these functions is a K&R-style function (no
// prototype), then we consider them to have matching signatures.
if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
isa<FunctionNoProtoType>(NewQType.getTypePtr()))
return false;
FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType);
FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType);
// The signature of a function includes the types of its
// parameters (C++ 1.3.10), which includes the presence or absence
// of the ellipsis; see C++ DR 357).
if (OldQType != NewQType &&
(OldType->getNumArgs() != NewType->getNumArgs() ||
OldType->isVariadic() != NewType->isVariadic() ||
!std::equal(OldType->arg_type_begin(), OldType->arg_type_end(),
NewType->arg_type_begin())))
return true;
// C++ [temp.over.link]p4:
// The signature of a function template consists of its function
// signature, its return type and its template parameter list. The names
// of the template parameters are significant only for establishing the
// relationship between the template parameters and the rest of the
// signature.
//
// We check the return type and template parameter lists for function
// templates first; the remaining checks follow.
if (NewTemplate &&
(!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
OldTemplate->getTemplateParameters(),
false, false, SourceLocation()) ||
OldType->getResultType() != NewType->getResultType()))
return true;
// If the function is a class member, its signature includes the
// cv-qualifiers (if any) on the function itself.
//
// As part of this, also check whether one of the member functions
// is static, in which case they are not overloads (C++
// 13.1p2). While not part of the definition of the signature,
// this check is important to determine whether these functions
// can be overloaded.
CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old);
CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New);
if (OldMethod && NewMethod &&
!OldMethod->isStatic() && !NewMethod->isStatic() &&
OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers())
return true;
// The signatures match; this is not an overload.
return false;
} else {
// (C++ 13p1):
// Only function declarations can be overloaded; object and type
// declarations cannot be overloaded.
return false;
}
}
/// TryImplicitConversion - Attempt to perform an implicit conversion
/// from the given expression (Expr) to the given type (ToType). This
/// function returns an implicit conversion sequence that can be used
/// to perform the initialization. Given
///
/// void f(float f);
/// void g(int i) { f(i); }
///
/// this routine would produce an implicit conversion sequence to
/// describe the initialization of f from i, which will be a standard
/// conversion sequence containing an lvalue-to-rvalue conversion (C++
/// 4.1) followed by a floating-integral conversion (C++ 4.9).
//
/// Note that this routine only determines how the conversion can be
/// performed; it does not actually perform the conversion. As such,
/// it will not produce any diagnostics if no conversion is available,
/// but will instead return an implicit conversion sequence of kind
/// "BadConversion".
///
/// If @p SuppressUserConversions, then user-defined conversions are
/// not permitted.
/// If @p AllowExplicit, then explicit user-defined conversions are
/// permitted.
/// If @p ForceRValue, then overloading is performed as if From was an rvalue,
/// no matter its actual lvalueness.
ImplicitConversionSequence
Sema::TryImplicitConversion(Expr* From, QualType ToType,
bool SuppressUserConversions,
bool AllowExplicit, bool ForceRValue)
{
ImplicitConversionSequence ICS;
if (IsStandardConversion(From, ToType, ICS.Standard))
ICS.ConversionKind = ImplicitConversionSequence::StandardConversion;
else if (getLangOptions().CPlusPlus &&
IsUserDefinedConversion(From, ToType, ICS.UserDefined,
!SuppressUserConversions, AllowExplicit,
ForceRValue)) {
ICS.ConversionKind = ImplicitConversionSequence::UserDefinedConversion;
// C++ [over.ics.user]p4:
// A conversion of an expression of class type to the same class
// type is given Exact Match rank, and a conversion of an
// expression of class type to a base class of that type is
// given Conversion rank, in spite of the fact that a copy
// constructor (i.e., a user-defined conversion function) is
// called for those cases.
if (CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
QualType FromCanon
= Context.getCanonicalType(From->getType().getUnqualifiedType());
QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) {
// Turn this into a "standard" conversion sequence, so that it
// gets ranked with standard conversion sequences.
ICS.ConversionKind = ImplicitConversionSequence::StandardConversion;
ICS.Standard.setAsIdentityConversion();
ICS.Standard.FromTypePtr = From->getType().getAsOpaquePtr();
ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr();
ICS.Standard.CopyConstructor = Constructor;
if (ToCanon != FromCanon)
ICS.Standard.Second = ICK_Derived_To_Base;
}
}
// C++ [over.best.ics]p4:
// However, when considering the argument of a user-defined
// conversion function that is a candidate by 13.3.1.3 when
// invoked for the copying of the temporary in the second step
// of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or
// 13.3.1.6 in all cases, only standard conversion sequences and
// ellipsis conversion sequences are allowed.
if (SuppressUserConversions &&
ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion)
ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
} else
ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
return ICS;
}
/// IsStandardConversion - Determines whether there is a standard
/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
/// expression From to the type ToType. Standard conversion sequences
/// only consider non-class types; for conversions that involve class
/// types, use TryImplicitConversion. If a conversion exists, SCS will
/// contain the standard conversion sequence required to perform this
/// conversion and this routine will return true. Otherwise, this
/// routine will return false and the value of SCS is unspecified.
bool
Sema::IsStandardConversion(Expr* From, QualType ToType,
StandardConversionSequence &SCS)
{
QualType FromType = From->getType();
// Standard conversions (C++ [conv])
SCS.setAsIdentityConversion();
SCS.Deprecated = false;
SCS.IncompatibleObjC = false;
SCS.FromTypePtr = FromType.getAsOpaquePtr();
SCS.CopyConstructor = 0;
// There are no standard conversions for class types in C++, so
// abort early. When overloading in C, however, we do permit
if (FromType->isRecordType() || ToType->isRecordType()) {
if (getLangOptions().CPlusPlus)
return false;
// When we're overloading in C, we allow, as standard conversions,
}
// The first conversion can be an lvalue-to-rvalue conversion,
// array-to-pointer conversion, or function-to-pointer conversion
// (C++ 4p1).
// Lvalue-to-rvalue conversion (C++ 4.1):
// An lvalue (3.10) of a non-function, non-array type T can be
// converted to an rvalue.
Expr::isLvalueResult argIsLvalue = From->isLvalue(Context);
if (argIsLvalue == Expr::LV_Valid &&
!FromType->isFunctionType() && !FromType->isArrayType() &&
Context.getCanonicalType(FromType) != Context.OverloadTy) {
SCS.First = ICK_Lvalue_To_Rvalue;
// If T is a non-class type, the type of the rvalue is the
// cv-unqualified version of T. Otherwise, the type of the rvalue
// is T (C++ 4.1p1). C++ can't get here with class types; in C, we
// just strip the qualifiers because they don't matter.
// FIXME: Doesn't see through to qualifiers behind a typedef!
FromType = FromType.getUnqualifiedType();
} else if (FromType->isArrayType()) {
// Array-to-pointer conversion (C++ 4.2)
SCS.First = ICK_Array_To_Pointer;
// An lvalue or rvalue of type "array of N T" or "array of unknown
// bound of T" can be converted to an rvalue of type "pointer to
// T" (C++ 4.2p1).
FromType = Context.getArrayDecayedType(FromType);
if (IsStringLiteralToNonConstPointerConversion(From, ToType)) {
// This conversion is deprecated. (C++ D.4).
SCS.Deprecated = true;
// For the purpose of ranking in overload resolution
// (13.3.3.1.1), this conversion is considered an
// array-to-pointer conversion followed by a qualification
// conversion (4.4). (C++ 4.2p2)
SCS.Second = ICK_Identity;
SCS.Third = ICK_Qualification;
SCS.ToTypePtr = ToType.getAsOpaquePtr();
return true;
}
} else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) {
// Function-to-pointer conversion (C++ 4.3).
SCS.First = ICK_Function_To_Pointer;
// An lvalue of function type T can be converted to an rvalue of
// type "pointer to T." The result is a pointer to the
// function. (C++ 4.3p1).
FromType = Context.getPointerType(FromType);
} else if (FunctionDecl *Fn
= ResolveAddressOfOverloadedFunction(From, ToType, false)) {
// Address of overloaded function (C++ [over.over]).
SCS.First = ICK_Function_To_Pointer;
// We were able to resolve the address of the overloaded function,
// so we can convert to the type of that function.
FromType = Fn->getType();
if (ToType->isLValueReferenceType())
FromType = Context.getLValueReferenceType(FromType);
else if (ToType->isRValueReferenceType())
FromType = Context.getRValueReferenceType(FromType);
else if (ToType->isMemberPointerType()) {
// Resolve address only succeeds if both sides are member pointers,
// but it doesn't have to be the same class. See DR 247.
// Note that this means that the type of &Derived::fn can be
// Ret (Base::*)(Args) if the fn overload actually found is from the
// base class, even if it was brought into the derived class via a
// using declaration. The standard isn't clear on this issue at all.
CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
FromType = Context.getMemberPointerType(FromType,
Context.getTypeDeclType(M->getParent()).getTypePtr());
} else
FromType = Context.getPointerType(FromType);
} else {
// We don't require any conversions for the first step.
SCS.First = ICK_Identity;
}
// The second conversion can be an integral promotion, floating
// point promotion, integral conversion, floating point conversion,
// floating-integral conversion, pointer conversion,
// pointer-to-member conversion, or boolean conversion (C++ 4p1).
// For overloading in C, this can also be a "compatible-type"
// conversion.
bool IncompatibleObjC = false;
if (Context.hasSameUnqualifiedType(FromType, ToType)) {
// The unqualified versions of the types are the same: there's no
// conversion to do.
SCS.Second = ICK_Identity;
} else if (IsIntegralPromotion(From, FromType, ToType)) {
// Integral promotion (C++ 4.5).
SCS.Second = ICK_Integral_Promotion;
FromType = ToType.getUnqualifiedType();
} else if (IsFloatingPointPromotion(FromType, ToType)) {
// Floating point promotion (C++ 4.6).
SCS.Second = ICK_Floating_Promotion;
FromType = ToType.getUnqualifiedType();
} else if (IsComplexPromotion(FromType, ToType)) {
// Complex promotion (Clang extension)
SCS.Second = ICK_Complex_Promotion;
FromType = ToType.getUnqualifiedType();
} else if ((FromType->isIntegralType() || FromType->isEnumeralType()) &&
(ToType->isIntegralType() && !ToType->isEnumeralType())) {
// Integral conversions (C++ 4.7).
// FIXME: isIntegralType shouldn't be true for enums in C++.
SCS.Second = ICK_Integral_Conversion;
FromType = ToType.getUnqualifiedType();
} else if (FromType->isFloatingType() && ToType->isFloatingType()) {
// Floating point conversions (C++ 4.8).
SCS.Second = ICK_Floating_Conversion;
FromType = ToType.getUnqualifiedType();
} else if (FromType->isComplexType() && ToType->isComplexType()) {
// Complex conversions (C99 6.3.1.6)
SCS.Second = ICK_Complex_Conversion;
FromType = ToType.getUnqualifiedType();
} else if ((FromType->isFloatingType() &&
ToType->isIntegralType() && (!ToType->isBooleanType() &&
!ToType->isEnumeralType())) ||
((FromType->isIntegralType() || FromType->isEnumeralType()) &&
ToType->isFloatingType())) {
// Floating-integral conversions (C++ 4.9).
// FIXME: isIntegralType shouldn't be true for enums in C++.
SCS.Second = ICK_Floating_Integral;
FromType = ToType.getUnqualifiedType();
} else if ((FromType->isComplexType() && ToType->isArithmeticType()) ||
(ToType->isComplexType() && FromType->isArithmeticType())) {
// Complex-real conversions (C99 6.3.1.7)
SCS.Second = ICK_Complex_Real;
FromType = ToType.getUnqualifiedType();
} else if (IsPointerConversion(From, FromType, ToType, FromType,
IncompatibleObjC)) {
// Pointer conversions (C++ 4.10).
SCS.Second = ICK_Pointer_Conversion;
SCS.IncompatibleObjC = IncompatibleObjC;
} else if (IsMemberPointerConversion(From, FromType, ToType, FromType)) {
// Pointer to member conversions (4.11).
SCS.Second = ICK_Pointer_Member;
} else if (ToType->isBooleanType() &&
(FromType->isArithmeticType() ||
FromType->isEnumeralType() ||
FromType->isPointerType() ||
FromType->isBlockPointerType() ||
FromType->isMemberPointerType() ||
FromType->isNullPtrType())) {
// Boolean conversions (C++ 4.12).
SCS.Second = ICK_Boolean_Conversion;
FromType = Context.BoolTy;
} else if (!getLangOptions().CPlusPlus &&
Context.typesAreCompatible(ToType, FromType)) {
// Compatible conversions (Clang extension for C function overloading)
SCS.Second = ICK_Compatible_Conversion;
} else {
// No second conversion required.
SCS.Second = ICK_Identity;
}
QualType CanonFrom;
QualType CanonTo;
// The third conversion can be a qualification conversion (C++ 4p1).
if (IsQualificationConversion(FromType, ToType)) {
SCS.Third = ICK_Qualification;
FromType = ToType;
CanonFrom = Context.getCanonicalType(FromType);
CanonTo = Context.getCanonicalType(ToType);
} else {
// No conversion required
SCS.Third = ICK_Identity;
// C++ [over.best.ics]p6:
// [...] Any difference in top-level cv-qualification is
// subsumed by the initialization itself and does not constitute
// a conversion. [...]
CanonFrom = Context.getCanonicalType(FromType);
CanonTo = Context.getCanonicalType(ToType);
if (CanonFrom.getUnqualifiedType() == CanonTo.getUnqualifiedType() &&
CanonFrom.getCVRQualifiers() != CanonTo.getCVRQualifiers()) {
FromType = ToType;
CanonFrom = CanonTo;
}
}
// If we have not converted the argument type to the parameter type,
// this is a bad conversion sequence.
if (CanonFrom != CanonTo)
return false;
SCS.ToTypePtr = FromType.getAsOpaquePtr();
return true;
}
/// IsIntegralPromotion - Determines whether the conversion from the
/// expression From (whose potentially-adjusted type is FromType) to
/// ToType is an integral promotion (C++ 4.5). If so, returns true and
/// sets PromotedType to the promoted type.
bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType)
{
const BuiltinType *To = ToType->getAsBuiltinType();
// All integers are built-in.
if (!To) {
return false;
}
// An rvalue of type char, signed char, unsigned char, short int, or
// unsigned short int can be converted to an rvalue of type int if
// int can represent all the values of the source type; otherwise,
// the source rvalue can be converted to an rvalue of type unsigned
// int (C++ 4.5p1).
if (FromType->isPromotableIntegerType() && !FromType->isBooleanType()) {
if (// We can promote any signed, promotable integer type to an int
(FromType->isSignedIntegerType() ||
// We can promote any unsigned integer type whose size is
// less than int to an int.
(!FromType->isSignedIntegerType() &&
Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) {
return To->getKind() == BuiltinType::Int;
}
return To->getKind() == BuiltinType::UInt;
}
// An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2)
// can be converted to an rvalue of the first of the following types
// that can represent all the values of its underlying type: int,
// unsigned int, long, or unsigned long (C++ 4.5p2).
if ((FromType->isEnumeralType() || FromType->isWideCharType())
&& ToType->isIntegerType()) {
// Determine whether the type we're converting from is signed or
// unsigned.
bool FromIsSigned;
uint64_t FromSize = Context.getTypeSize(FromType);
if (const EnumType *FromEnumType = FromType->getAsEnumType()) {
QualType UnderlyingType = FromEnumType->getDecl()->getIntegerType();
FromIsSigned = UnderlyingType->isSignedIntegerType();
} else {
// FIXME: Is wchar_t signed or unsigned? We assume it's signed for now.
FromIsSigned = true;
}
// The types we'll try to promote to, in the appropriate
// order. Try each of these types.
QualType PromoteTypes[6] = {
Context.IntTy, Context.UnsignedIntTy,
Context.LongTy, Context.UnsignedLongTy ,
Context.LongLongTy, Context.UnsignedLongLongTy
};
for (int Idx = 0; Idx < 6; ++Idx) {
uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
if (FromSize < ToSize ||
(FromSize == ToSize &&
FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
// We found the type that we can promote to. If this is the
// type we wanted, we have a promotion. Otherwise, no
// promotion.
return Context.getCanonicalType(ToType).getUnqualifiedType()
== Context.getCanonicalType(PromoteTypes[Idx]).getUnqualifiedType();
}
}
}
// An rvalue for an integral bit-field (9.6) can be converted to an
// rvalue of type int if int can represent all the values of the
// bit-field; otherwise, it can be converted to unsigned int if
// unsigned int can represent all the values of the bit-field. If
// the bit-field is larger yet, no integral promotion applies to
// it. If the bit-field has an enumerated type, it is treated as any
// other value of that type for promotion purposes (C++ 4.5p3).
// FIXME: We should delay checking of bit-fields until we actually perform the
// conversion.
using llvm::APSInt;
if (From)
if (FieldDecl *MemberDecl = From->getBitField()) {
APSInt BitWidth;
if (FromType->isIntegralType() && !FromType->isEnumeralType() &&
MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) {
APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned());
ToSize = Context.getTypeSize(ToType);
// Are we promoting to an int from a bitfield that fits in an int?
if (BitWidth < ToSize ||
(FromType->isSignedIntegerType() && BitWidth <= ToSize)) {
return To->getKind() == BuiltinType::Int;
}
// Are we promoting to an unsigned int from an unsigned bitfield
// that fits into an unsigned int?
if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) {
return To->getKind() == BuiltinType::UInt;
}
return false;
}
}
// An rvalue of type bool can be converted to an rvalue of type int,
// with false becoming zero and true becoming one (C++ 4.5p4).
if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
return true;
}
return false;
}
/// IsFloatingPointPromotion - Determines whether the conversion from
/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
/// returns true and sets PromotedType to the promoted type.
bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType)
{
/// An rvalue of type float can be converted to an rvalue of type
/// double. (C++ 4.6p1).
if (const BuiltinType *FromBuiltin = FromType->getAsBuiltinType())
if (const BuiltinType *ToBuiltin = ToType->getAsBuiltinType()) {
if (FromBuiltin->getKind() == BuiltinType::Float &&
ToBuiltin->getKind() == BuiltinType::Double)
return true;
// C99 6.3.1.5p1:
// When a float is promoted to double or long double, or a
// double is promoted to long double [...].
if (!getLangOptions().CPlusPlus &&
(FromBuiltin->getKind() == BuiltinType::Float ||
FromBuiltin->getKind() == BuiltinType::Double) &&
(ToBuiltin->getKind() == BuiltinType::LongDouble))
return true;
}
return false;
}
/// \brief Determine if a conversion is a complex promotion.
///
/// A complex promotion is defined as a complex -> complex conversion
/// where the conversion between the underlying real types is a
/// floating-point or integral promotion.
bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
const ComplexType *FromComplex = FromType->getAsComplexType();
if (!FromComplex)
return false;
const ComplexType *ToComplex = ToType->getAsComplexType();
if (!ToComplex)
return false;
return IsFloatingPointPromotion(FromComplex->getElementType(),
ToComplex->getElementType()) ||
IsIntegralPromotion(0, FromComplex->getElementType(),
ToComplex->getElementType());
}
/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
/// the pointer type FromPtr to a pointer to type ToPointee, with the
/// same type qualifiers as FromPtr has on its pointee type. ToType,
/// if non-empty, will be a pointer to ToType that may or may not have
/// the right set of qualifiers on its pointee.
static QualType
BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr,
QualType ToPointee, QualType ToType,
ASTContext &Context) {
QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType());
QualType CanonToPointee = Context.getCanonicalType(ToPointee);
unsigned Quals = CanonFromPointee.getCVRQualifiers();
// Exact qualifier match -> return the pointer type we're converting to.
if (CanonToPointee.getCVRQualifiers() == Quals) {
// ToType is exactly what we need. Return it.
if (ToType.getTypePtr())
return ToType;
// Build a pointer to ToPointee. It has the right qualifiers
// already.
return Context.getPointerType(ToPointee);
}
// Just build a canonical type that has the right qualifiers.
return Context.getPointerType(CanonToPointee.getQualifiedType(Quals));
}
/// IsPointerConversion - Determines whether the conversion of the
/// expression From, which has the (possibly adjusted) type FromType,
/// can be converted to the type ToType via a pointer conversion (C++
/// 4.10). If so, returns true and places the converted type (that
/// might differ from ToType in its cv-qualifiers at some level) into
/// ConvertedType.
///
/// This routine also supports conversions to and from block pointers
/// and conversions with Objective-C's 'id', 'id<protocols...>', and
/// pointers to interfaces. FIXME: Once we've determined the
/// appropriate overloading rules for Objective-C, we may want to
/// split the Objective-C checks into a different routine; however,
/// GCC seems to consider all of these conversions to be pointer
/// conversions, so for now they live here. IncompatibleObjC will be
/// set if the conversion is an allowed Objective-C conversion that
/// should result in a warning.
bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
QualType& ConvertedType,
bool &IncompatibleObjC)
{
IncompatibleObjC = false;
if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC))
return true;
// Conversion from a null pointer constant to any Objective-C pointer type.
if (ToType->isObjCObjectPointerType() &&
From->isNullPointerConstant(Context)) {
ConvertedType = ToType;
return true;
}
// Blocks: Block pointers can be converted to void*.
if (FromType->isBlockPointerType() && ToType->isPointerType() &&
ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) {
ConvertedType = ToType;
return true;
}
// Blocks: A null pointer constant can be converted to a block
// pointer type.
if (ToType->isBlockPointerType() && From->isNullPointerConstant(Context)) {
ConvertedType = ToType;
return true;
}
// If the left-hand-side is nullptr_t, the right side can be a null
// pointer constant.
if (ToType->isNullPtrType() && From->isNullPointerConstant(Context)) {
ConvertedType = ToType;
return true;
}
const PointerType* ToTypePtr = ToType->getAs<PointerType>();
if (!ToTypePtr)
return false;
// A null pointer constant can be converted to a pointer type (C++ 4.10p1).
if (From->isNullPointerConstant(Context)) {
ConvertedType = ToType;
return true;
}
// Beyond this point, both types need to be pointers.
const PointerType *FromTypePtr = FromType->getAs<PointerType>();
if (!FromTypePtr)
return false;
QualType FromPointeeType = FromTypePtr->getPointeeType();
QualType ToPointeeType = ToTypePtr->getPointeeType();
// An rvalue of type "pointer to cv T," where T is an object type,
// can be converted to an rvalue of type "pointer to cv void" (C++
// 4.10p2).
if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
// When we're overloading in C, we allow a special kind of pointer
// conversion for compatible-but-not-identical pointee types.
if (!getLangOptions().CPlusPlus &&
Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
// C++ [conv.ptr]p3:
//
// An rvalue of type "pointer to cv D," where D is a class type,
// can be converted to an rvalue of type "pointer to cv B," where
// B is a base class (clause 10) of D. If B is an inaccessible
// (clause 11) or ambiguous (10.2) base class of D, a program that
// necessitates this conversion is ill-formed. The result of the
// conversion is a pointer to the base class sub-object of the
// derived class object. The null pointer value is converted to
// the null pointer value of the destination type.
//
// Note that we do not check for ambiguity or inaccessibility
// here. That is handled by CheckPointerConversion.
if (getLangOptions().CPlusPlus &&
FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
IsDerivedFrom(FromPointeeType, ToPointeeType)) {
ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
ToPointeeType,
ToType, Context);
return true;
}
return false;
}
/// isObjCPointerConversion - Determines whether this is an
/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
/// with the same arguments and return values.
bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
QualType& ConvertedType,
bool &IncompatibleObjC) {
if (!getLangOptions().ObjC1)
return false;
// First, we handle all conversions on ObjC object pointer types.
const ObjCObjectPointerType* ToObjCPtr = ToType->getAsObjCObjectPointerType();
const ObjCObjectPointerType *FromObjCPtr =
FromType->getAsObjCObjectPointerType();
if (ToObjCPtr && FromObjCPtr) {
// Objective C++: We're able to convert between "id" or "Class" and a
// pointer to any interface (in both directions).
if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) {
ConvertedType = ToType;
return true;
}
// Conversions with Objective-C's id<...>.
if ((FromObjCPtr->isObjCQualifiedIdType() ||
ToObjCPtr->isObjCQualifiedIdType()) &&
Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType,
/*compare=*/false)) {
ConvertedType = ToType;
return true;
}
// Objective C++: We're able to convert from a pointer to an
// interface to a pointer to a different interface.
if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
ConvertedType = ToType;
return true;
}
if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
// Okay: this is some kind of implicit downcast of Objective-C
// interfaces, which is permitted. However, we're going to
// complain about it.
IncompatibleObjC = true;
ConvertedType = FromType;
return true;
}
}
// Beyond this point, both types need to be C pointers or block pointers.
QualType ToPointeeType;
if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
ToPointeeType = ToCPtr->getPointeeType();
else if (const BlockPointerType *ToBlockPtr = ToType->getAs<BlockPointerType>())
ToPointeeType = ToBlockPtr->getPointeeType();
else
return false;
QualType FromPointeeType;
if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
FromPointeeType = FromCPtr->getPointeeType();
else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>())
FromPointeeType = FromBlockPtr->getPointeeType();
else
return false;
// If we have pointers to pointers, recursively check whether this
// is an Objective-C conversion.
if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
IncompatibleObjC)) {
// We always complain about this conversion.
IncompatibleObjC = true;
ConvertedType = ToType;
return true;
}
// If we have pointers to functions or blocks, check whether the only
// differences in the argument and result types are in Objective-C
// pointer conversions. If so, we permit the conversion (but
// complain about it).
const FunctionProtoType *FromFunctionType
= FromPointeeType->getAsFunctionProtoType();
const FunctionProtoType *ToFunctionType
= ToPointeeType->getAsFunctionProtoType();
if (FromFunctionType && ToFunctionType) {
// If the function types are exactly the same, this isn't an
// Objective-C pointer conversion.
if (Context.getCanonicalType(FromPointeeType)
== Context.getCanonicalType(ToPointeeType))
return false;
// Perform the quick checks that will tell us whether these
// function types are obviously different.
if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() ||
FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals())
return false;
bool HasObjCConversion = false;
if (Context.getCanonicalType(FromFunctionType->getResultType())
== Context.getCanonicalType(ToFunctionType->getResultType())) {
// Okay, the types match exactly. Nothing to do.
} else if (isObjCPointerConversion(FromFunctionType->getResultType(),
ToFunctionType->getResultType(),
ConvertedType, IncompatibleObjC)) {
// Okay, we have an Objective-C pointer conversion.
HasObjCConversion = true;
} else {
// Function types are too different. Abort.
return false;
}
// Check argument types.
for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs();
ArgIdx != NumArgs; ++ArgIdx) {
QualType FromArgType = FromFunctionType->getArgType(ArgIdx);
QualType ToArgType = ToFunctionType->getArgType(ArgIdx);
if (Context.getCanonicalType(FromArgType)
== Context.getCanonicalType(ToArgType)) {
// Okay, the types match exactly. Nothing to do.
} else if (isObjCPointerConversion(FromArgType, ToArgType,
ConvertedType, IncompatibleObjC)) {
// Okay, we have an Objective-C pointer conversion.
HasObjCConversion = true;
} else {
// Argument types are too different. Abort.
return false;
}
}
if (HasObjCConversion) {
// We had an Objective-C conversion. Allow this pointer
// conversion, but complain about it.
ConvertedType = ToType;
IncompatibleObjC = true;
return true;
}
}
return false;
}
/// CheckPointerConversion - Check the pointer conversion from the
/// expression From to the type ToType. This routine checks for
/// ambiguous or inaccessible derived-to-base pointer
/// conversions for which IsPointerConversion has already returned
/// true. It returns true and produces a diagnostic if there was an
/// error, or returns false otherwise.
bool Sema::CheckPointerConversion(Expr *From, QualType ToType) {
QualType FromType = From->getType();
if (const PointerType *FromPtrType = FromType->getAs<PointerType>())
if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
QualType FromPointeeType = FromPtrType->getPointeeType(),
ToPointeeType = ToPtrType->getPointeeType();
if (FromPointeeType->isRecordType() &&
ToPointeeType->isRecordType()) {
// We must have a derived-to-base conversion. Check an
// ambiguous or inaccessible conversion.
return CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType,
From->getExprLoc(),
From->getSourceRange());
}
}
if (const ObjCObjectPointerType *FromPtrType =
FromType->getAsObjCObjectPointerType())
if (const ObjCObjectPointerType *ToPtrType =
ToType->getAsObjCObjectPointerType()) {
// Objective-C++ conversions are always okay.
// FIXME: We should have a different class of conversions for the
// Objective-C++ implicit conversions.
if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
return false;
}
return false;
}
/// IsMemberPointerConversion - Determines whether the conversion of the
/// expression From, which has the (possibly adjusted) type FromType, can be
/// converted to the type ToType via a member pointer conversion (C++ 4.11).
/// If so, returns true and places the converted type (that might differ from
/// ToType in its cv-qualifiers at some level) into ConvertedType.
bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
QualType ToType, QualType &ConvertedType)
{
const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
if (!ToTypePtr)
return false;
// A null pointer constant can be converted to a member pointer (C++ 4.11p1)
if (From->isNullPointerConstant(Context)) {
ConvertedType = ToType;
return true;
}
// Otherwise, both types have to be member pointers.
const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
if (!FromTypePtr)
return false;
// A pointer to member of B can be converted to a pointer to member of D,
// where D is derived from B (C++ 4.11p2).
QualType FromClass(FromTypePtr->getClass(), 0);
QualType ToClass(ToTypePtr->getClass(), 0);
// FIXME: What happens when these are dependent? Is this function even called?
if (IsDerivedFrom(ToClass, FromClass)) {
ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
ToClass.getTypePtr());
return true;
}
return false;
}
/// CheckMemberPointerConversion - Check the member pointer conversion from the
/// expression From to the type ToType. This routine checks for ambiguous or
/// virtual (FIXME: or inaccessible) base-to-derived member pointer conversions
/// for which IsMemberPointerConversion has already returned true. It returns
/// true and produces a diagnostic if there was an error, or returns false
/// otherwise.
bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType) {
QualType FromType = From->getType();
const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
if (!FromPtrType)
return false;
const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
assert(ToPtrType && "No member pointer cast has a target type "
"that is not a member pointer.");
QualType FromClass = QualType(FromPtrType->getClass(), 0);
QualType ToClass = QualType(ToPtrType->getClass(), 0);
// FIXME: What about dependent types?
assert(FromClass->isRecordType() && "Pointer into non-class.");
assert(ToClass->isRecordType() && "Pointer into non-class.");
BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
/*DetectVirtual=*/true);
bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths);
assert(DerivationOkay &&
"Should not have been called if derivation isn't OK.");
(void)DerivationOkay;
if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
getUnqualifiedType())) {
// Derivation is ambiguous. Redo the check to find the exact paths.
Paths.clear();
Paths.setRecordingPaths(true);
bool StillOkay = IsDerivedFrom(ToClass, FromClass, Paths);
assert(StillOkay && "Derivation changed due to quantum fluctuation.");
(void)StillOkay;
std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
<< 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
return true;
}
if (const RecordType *VBase = Paths.getDetectedVirtual()) {
Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
<< FromClass << ToClass << QualType(VBase, 0)
<< From->getSourceRange();
return true;
}
return false;
}
/// IsQualificationConversion - Determines whether the conversion from
/// an rvalue of type FromType to ToType is a qualification conversion
/// (C++ 4.4).
bool
Sema::IsQualificationConversion(QualType FromType, QualType ToType)
{
FromType = Context.getCanonicalType(FromType);
ToType = Context.getCanonicalType(ToType);
// If FromType and ToType are the same type, this is not a
// qualification conversion.
if (FromType == ToType)
return false;
// (C++ 4.4p4):
// A conversion can add cv-qualifiers at levels other than the first
// in multi-level pointers, subject to the following rules: [...]
bool PreviousToQualsIncludeConst = true;
bool UnwrappedAnyPointer = false;
while (UnwrapSimilarPointerTypes(FromType, ToType)) {
// Within each iteration of the loop, we check the qualifiers to
// determine if this still looks like a qualification
// conversion. Then, if all is well, we unwrap one more level of
// pointers or pointers-to-members and do it all again
// until there are no more pointers or pointers-to-members left to
// unwrap.
UnwrappedAnyPointer = true;
// -- for every j > 0, if const is in cv 1,j then const is in cv
// 2,j, and similarly for volatile.
if (!ToType.isAtLeastAsQualifiedAs(FromType))
return false;
// -- if the cv 1,j and cv 2,j are different, then const is in
// every cv for 0 < k < j.
if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers()
&& !PreviousToQualsIncludeConst)
return false;
// Keep track of whether all prior cv-qualifiers in the "to" type
// include const.
PreviousToQualsIncludeConst
= PreviousToQualsIncludeConst && ToType.isConstQualified();
}
// We are left with FromType and ToType being the pointee types
// after unwrapping the original FromType and ToType the same number
// of types. If we unwrapped any pointers, and if FromType and
// ToType have the same unqualified type (since we checked
// qualifiers above), then this is a qualification conversion.
return UnwrappedAnyPointer &&
FromType.getUnqualifiedType() == ToType.getUnqualifiedType();
}
/// \brief Given a function template or function, extract the function template
/// declaration (if any) and the underlying function declaration.
template<typename T>
static void GetFunctionAndTemplate(AnyFunctionDecl Orig, T *&Function,
FunctionTemplateDecl *&FunctionTemplate) {
FunctionTemplate = dyn_cast<FunctionTemplateDecl>(Orig);
if (FunctionTemplate)
Function = cast<T>(FunctionTemplate->getTemplatedDecl());
else
Function = cast<T>(Orig);
}
/// Determines whether there is a user-defined conversion sequence
/// (C++ [over.ics.user]) that converts expression From to the type
/// ToType. If such a conversion exists, User will contain the
/// user-defined conversion sequence that performs such a conversion
/// and this routine will return true. Otherwise, this routine returns
/// false and User is unspecified.
///
/// \param AllowConversionFunctions true if the conversion should
/// consider conversion functions at all. If false, only constructors
/// will be considered.
///
/// \param AllowExplicit true if the conversion should consider C++0x
/// "explicit" conversion functions as well as non-explicit conversion
/// functions (C++0x [class.conv.fct]p2).
///
/// \param ForceRValue true if the expression should be treated as an rvalue
/// for overload resolution.
bool Sema::IsUserDefinedConversion(Expr *From, QualType ToType,
UserDefinedConversionSequence& User,
bool AllowConversionFunctions,
bool AllowExplicit, bool ForceRValue)
{
OverloadCandidateSet CandidateSet;
if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
if (CXXRecordDecl *ToRecordDecl
= dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
// C++ [over.match.ctor]p1:
// When objects of class type are direct-initialized (8.5), or
// copy-initialized from an expression of the same or a
// derived class type (8.5), overload resolution selects the
// constructor. [...] For copy-initialization, the candidate
// functions are all the converting constructors (12.3.1) of
// that class. The argument list is the expression-list within
// the parentheses of the initializer.
DeclarationName ConstructorName
= Context.DeclarationNames.getCXXConstructorName(
Context.getCanonicalType(ToType).getUnqualifiedType());
DeclContext::lookup_iterator Con, ConEnd;
for (llvm::tie(Con, ConEnd)
= ToRecordDecl->lookup(ConstructorName);
Con != ConEnd; ++Con) {
// Find the constructor (which may be a template).
CXXConstructorDecl *Constructor = 0;
FunctionTemplateDecl *ConstructorTmpl
= dyn_cast<FunctionTemplateDecl>(*Con);
if (ConstructorTmpl)
Constructor
= cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl());
else
Constructor = cast<CXXConstructorDecl>(*Con);
if (!Constructor->isInvalidDecl() &&
Constructor->isConvertingConstructor()) {
if (ConstructorTmpl)
AddTemplateOverloadCandidate(ConstructorTmpl, false, 0, 0, &From,
1, CandidateSet,
/*SuppressUserConversions=*/true,
ForceRValue);
else
AddOverloadCandidate(Constructor, &From, 1, CandidateSet,
/*SuppressUserConversions=*/true, ForceRValue);
}
}
}
}
if (!AllowConversionFunctions) {
// Don't allow any conversion functions to enter the overload set.
} else if (const RecordType *FromRecordType
= From->getType()->getAs<RecordType>()) {
if (CXXRecordDecl *FromRecordDecl
= dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
// Add all of the conversion functions as candidates.
// FIXME: Look for conversions in base classes!
OverloadedFunctionDecl *Conversions
= FromRecordDecl->getConversionFunctions();
for (OverloadedFunctionDecl::function_iterator Func
= Conversions->function_begin();
Func != Conversions->function_end(); ++Func) {
CXXConversionDecl *Conv;
FunctionTemplateDecl *ConvTemplate;
GetFunctionAndTemplate(*Func, Conv, ConvTemplate);
if (ConvTemplate)
Conv = dyn_cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
else
Conv = dyn_cast<CXXConversionDecl>(*Func);
if (AllowExplicit || !Conv->isExplicit()) {
if (ConvTemplate)
AddTemplateConversionCandidate(ConvTemplate, From, ToType,
CandidateSet);
else
AddConversionCandidate(Conv, From, ToType, CandidateSet);
}
}
}
}
OverloadCandidateSet::iterator Best;
switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) {
case OR_Success:
// Record the standard conversion we used and the conversion function.
if (CXXConstructorDecl *Constructor
= dyn_cast<CXXConstructorDecl>(Best->Function)) {
// C++ [over.ics.user]p1:
// If the user-defined conversion is specified by a
// constructor (12.3.1), the initial standard conversion
// sequence converts the source type to the type required by
// the argument of the constructor.
//
// FIXME: What about ellipsis conversions?
QualType ThisType = Constructor->getThisType(Context);
User.Before = Best->Conversions[0].Standard;
User.ConversionFunction = Constructor;
User.After.setAsIdentityConversion();
User.After.FromTypePtr
= ThisType->getAs<PointerType>()->getPointeeType().getAsOpaquePtr();
User.After.ToTypePtr = ToType.getAsOpaquePtr();
return true;
} else if (CXXConversionDecl *Conversion
= dyn_cast<CXXConversionDecl>(Best->Function)) {
// C++ [over.ics.user]p1:
//
// [...] If the user-defined conversion is specified by a
// conversion function (12.3.2), the initial standard
// conversion sequence converts the source type to the
// implicit object parameter of the conversion function.
User.Before = Best->Conversions[0].Standard;
User.ConversionFunction = Conversion;
// C++ [over.ics.user]p2:
// The second standard conversion sequence converts the
// result of the user-defined conversion to the target type
// for the sequence. Since an implicit conversion sequence
// is an initialization, the special rules for
// initialization by user-defined conversion apply when
// selecting the best user-defined conversion for a
// user-defined conversion sequence (see 13.3.3 and
// 13.3.3.1).
User.After = Best->FinalConversion;
return true;
} else {
assert(false && "Not a constructor or conversion function?");
return false;
}
case OR_No_Viable_Function:
case OR_Deleted:
// No conversion here! We're done.
return false;
case OR_Ambiguous:
// FIXME: See C++ [over.best.ics]p10 for the handling of
// ambiguous conversion sequences.
return false;
}
return false;
}
/// CompareImplicitConversionSequences - Compare two implicit
/// conversion sequences to determine whether one is better than the
/// other or if they are indistinguishable (C++ 13.3.3.2).
ImplicitConversionSequence::CompareKind
Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1,
const ImplicitConversionSequence& ICS2)
{
// (C++ 13.3.3.2p2): When comparing the basic forms of implicit
// conversion sequences (as defined in 13.3.3.1)
// -- a standard conversion sequence (13.3.3.1.1) is a better
// conversion sequence than a user-defined conversion sequence or
// an ellipsis conversion sequence, and
// -- a user-defined conversion sequence (13.3.3.1.2) is a better
// conversion sequence than an ellipsis conversion sequence
// (13.3.3.1.3).
//
if (ICS1.ConversionKind < ICS2.ConversionKind)
return ImplicitConversionSequence::Better;
else if (ICS2.ConversionKind < ICS1.ConversionKind)
return ImplicitConversionSequence::Worse;
// Two implicit conversion sequences of the same form are
// indistinguishable conversion sequences unless one of the
// following rules apply: (C++ 13.3.3.2p3):
if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion)
return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard);
else if (ICS1.ConversionKind ==
ImplicitConversionSequence::UserDefinedConversion) {
// User-defined conversion sequence U1 is a better conversion
// sequence than another user-defined conversion sequence U2 if
// they contain the same user-defined conversion function or
// constructor and if the second standard conversion sequence of
// U1 is better than the second standard conversion sequence of
// U2 (C++ 13.3.3.2p3).
if (ICS1.UserDefined.ConversionFunction ==
ICS2.UserDefined.ConversionFunction)
return CompareStandardConversionSequences(ICS1.UserDefined.After,
ICS2.UserDefined.After);
}
return ImplicitConversionSequence::Indistinguishable;
}
/// CompareStandardConversionSequences - Compare two standard
/// conversion sequences to determine whether one is better than the
/// other or if they are indistinguishable (C++ 13.3.3.2p3).
ImplicitConversionSequence::CompareKind
Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2)
{
// Standard conversion sequence S1 is a better conversion sequence
// than standard conversion sequence S2 if (C++ 13.3.3.2p3):
// -- S1 is a proper subsequence of S2 (comparing the conversion
// sequences in the canonical form defined by 13.3.3.1.1,
// excluding any Lvalue Transformation; the identity conversion
// sequence is considered to be a subsequence of any
// non-identity conversion sequence) or, if not that,
if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third)
// Neither is a proper subsequence of the other. Do nothing.
;
else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) ||
(SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) ||
(SCS1.Second == ICK_Identity &&
SCS1.Third == ICK_Identity))
// SCS1 is a proper subsequence of SCS2.
return ImplicitConversionSequence::Better;
else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) ||
(SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) ||
(SCS2.Second == ICK_Identity &&
SCS2.Third == ICK_Identity))
// SCS2 is a proper subsequence of SCS1.
return ImplicitConversionSequence::Worse;
// -- the rank of S1 is better than the rank of S2 (by the rules
// defined below), or, if not that,
ImplicitConversionRank Rank1 = SCS1.getRank();
ImplicitConversionRank Rank2 = SCS2.getRank();
if (Rank1 < Rank2)
return ImplicitConversionSequence::Better;
else if (Rank2 < Rank1)
return ImplicitConversionSequence::Worse;
// (C++ 13.3.3.2p4): Two conversion sequences with the same rank
// are indistinguishable unless one of the following rules
// applies:
// A conversion that is not a conversion of a pointer, or
// pointer to member, to bool is better than another conversion
// that is such a conversion.
if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
return SCS2.isPointerConversionToBool()
? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
// C++ [over.ics.rank]p4b2:
//
// If class B is derived directly or indirectly from class A,
// conversion of B* to A* is better than conversion of B* to
// void*, and conversion of A* to void* is better than conversion
// of B* to void*.
bool SCS1ConvertsToVoid
= SCS1.isPointerConversionToVoidPointer(Context);
bool SCS2ConvertsToVoid
= SCS2.isPointerConversionToVoidPointer(Context);
if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
// Exactly one of the conversion sequences is a conversion to
// a void pointer; it's the worse conversion.
return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
} else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
// Neither conversion sequence converts to a void pointer; compare
// their derived-to-base conversions.
if (ImplicitConversionSequence::CompareKind DerivedCK
= CompareDerivedToBaseConversions(SCS1, SCS2))
return DerivedCK;
} else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) {
// Both conversion sequences are conversions to void
// pointers. Compare the source types to determine if there's an
// inheritance relationship in their sources.
QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr);
QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr);
// Adjust the types we're converting from via the array-to-pointer
// conversion, if we need to.
if (SCS1.First == ICK_Array_To_Pointer)
FromType1 = Context.getArrayDecayedType(FromType1);
if (SCS2.First == ICK_Array_To_Pointer)
FromType2 = Context.getArrayDecayedType(FromType2);
QualType FromPointee1
= FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType FromPointee2
= FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
if (IsDerivedFrom(FromPointee2, FromPointee1))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(FromPointee1, FromPointee2))
return ImplicitConversionSequence::Worse;
// Objective-C++: If one interface is more specific than the
// other, it is the better one.
const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType();
const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType();
if (FromIface1 && FromIface1) {
if (Context.canAssignObjCInterfaces(FromIface2, FromIface1))
return ImplicitConversionSequence::Better;
else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2))
return ImplicitConversionSequence::Worse;
}
}
// Compare based on qualification conversions (C++ 13.3.3.2p3,
// bullet 3).
if (ImplicitConversionSequence::CompareKind QualCK
= CompareQualificationConversions(SCS1, SCS2))
return QualCK;
if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
// C++0x [over.ics.rank]p3b4:
// -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
// implicit object parameter of a non-static member function declared
// without a ref-qualifier, and S1 binds an rvalue reference to an
// rvalue and S2 binds an lvalue reference.
// FIXME: We don't know if we're dealing with the implicit object parameter,
// or if the member function in this case has a ref qualifier.
// (Of course, we don't have ref qualifiers yet.)
if (SCS1.RRefBinding != SCS2.RRefBinding)
return SCS1.RRefBinding ? ImplicitConversionSequence::Better
: ImplicitConversionSequence::Worse;
// C++ [over.ics.rank]p3b4:
// -- S1 and S2 are reference bindings (8.5.3), and the types to
// which the references refer are the same type except for
// top-level cv-qualifiers, and the type to which the reference
// initialized by S2 refers is more cv-qualified than the type
// to which the reference initialized by S1 refers.
QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr);
QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr);
T1 = Context.getCanonicalType(T1);
T2 = Context.getCanonicalType(T2);
if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) {
if (T2.isMoreQualifiedThan(T1))
return ImplicitConversionSequence::Better;
else if (T1.isMoreQualifiedThan(T2))
return ImplicitConversionSequence::Worse;
}
}
return ImplicitConversionSequence::Indistinguishable;
}
/// CompareQualificationConversions - Compares two standard conversion
/// sequences to determine whether they can be ranked based on their
/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
ImplicitConversionSequence::CompareKind
Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2)
{
// C++ 13.3.3.2p3:
// -- S1 and S2 differ only in their qualification conversion and
// yield similar types T1 and T2 (C++ 4.4), respectively, and the
// cv-qualification signature of type T1 is a proper subset of
// the cv-qualification signature of type T2, and S1 is not the
// deprecated string literal array-to-pointer conversion (4.2).
if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
return ImplicitConversionSequence::Indistinguishable;
// FIXME: the example in the standard doesn't use a qualification
// conversion (!)
QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr);
QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr);
T1 = Context.getCanonicalType(T1);
T2 = Context.getCanonicalType(T2);
// If the types are the same, we won't learn anything by unwrapped
// them.
if (T1.getUnqualifiedType() == T2.getUnqualifiedType())
return ImplicitConversionSequence::Indistinguishable;
ImplicitConversionSequence::CompareKind Result
= ImplicitConversionSequence::Indistinguishable;
while (UnwrapSimilarPointerTypes(T1, T2)) {
// Within each iteration of the loop, we check the qualifiers to
// determine if this still looks like a qualification
// conversion. Then, if all is well, we unwrap one more level of
// pointers or pointers-to-members and do it all again
// until there are no more pointers or pointers-to-members left
// to unwrap. This essentially mimics what
// IsQualificationConversion does, but here we're checking for a
// strict subset of qualifiers.
if (T1.getCVRQualifiers() == T2.getCVRQualifiers())
// The qualifiers are the same, so this doesn't tell us anything
// about how the sequences rank.
;
else if (T2.isMoreQualifiedThan(T1)) {
// T1 has fewer qualifiers, so it could be the better sequence.
if (Result == ImplicitConversionSequence::Worse)
// Neither has qualifiers that are a subset of the other's
// qualifiers.
return ImplicitConversionSequence::Indistinguishable;
Result = ImplicitConversionSequence::Better;
} else if (T1.isMoreQualifiedThan(T2)) {
// T2 has fewer qualifiers, so it could be the better sequence.
if (Result == ImplicitConversionSequence::Better)
// Neither has qualifiers that are a subset of the other's
// qualifiers.
return ImplicitConversionSequence::Indistinguishable;
Result = ImplicitConversionSequence::Worse;
} else {
// Qualifiers are disjoint.
return ImplicitConversionSequence::Indistinguishable;
}
// If the types after this point are equivalent, we're done.
if (T1.getUnqualifiedType() == T2.getUnqualifiedType())
break;
}
// Check that the winning standard conversion sequence isn't using
// the deprecated string literal array to pointer conversion.
switch (Result) {
case ImplicitConversionSequence::Better:
if (SCS1.Deprecated)
Result = ImplicitConversionSequence::Indistinguishable;
break;
case ImplicitConversionSequence::Indistinguishable:
break;
case ImplicitConversionSequence::Worse:
if (SCS2.Deprecated)
Result = ImplicitConversionSequence::Indistinguishable;
break;
}
return Result;
}
/// CompareDerivedToBaseConversions - Compares two standard conversion
/// sequences to determine whether they can be ranked based on their
/// various kinds of derived-to-base conversions (C++
/// [over.ics.rank]p4b3). As part of these checks, we also look at
/// conversions between Objective-C interface types.
ImplicitConversionSequence::CompareKind
Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2) {
QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr);
QualType ToType1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr);
QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr);
QualType ToType2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr);
// Adjust the types we're converting from via the array-to-pointer
// conversion, if we need to.
if (SCS1.First == ICK_Array_To_Pointer)
FromType1 = Context.getArrayDecayedType(FromType1);
if (SCS2.First == ICK_Array_To_Pointer)
FromType2 = Context.getArrayDecayedType(FromType2);
// Canonicalize all of the types.
FromType1 = Context.getCanonicalType(FromType1);
ToType1 = Context.getCanonicalType(ToType1);
FromType2 = Context.getCanonicalType(FromType2);
ToType2 = Context.getCanonicalType(ToType2);
// C++ [over.ics.rank]p4b3:
//
// If class B is derived directly or indirectly from class A and
// class C is derived directly or indirectly from B,
//
// For Objective-C, we let A, B, and C also be Objective-C
// interfaces.
// Compare based on pointer conversions.
if (SCS1.Second == ICK_Pointer_Conversion &&
SCS2.Second == ICK_Pointer_Conversion &&
/*FIXME: Remove if Objective-C id conversions get their own rank*/
FromType1->isPointerType() && FromType2->isPointerType() &&
ToType1->isPointerType() && ToType2->isPointerType()) {
QualType FromPointee1
= FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType ToPointee1
= ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType FromPointee2
= FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
QualType ToPointee2
= ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType();
const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType();
const ObjCInterfaceType* ToIface1 = ToPointee1->getAsObjCInterfaceType();
const ObjCInterfaceType* ToIface2 = ToPointee2->getAsObjCInterfaceType();
// -- conversion of C* to B* is better than conversion of C* to A*,
if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
if (IsDerivedFrom(ToPointee1, ToPointee2))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(ToPointee2, ToPointee1))
return ImplicitConversionSequence::Worse;
if (ToIface1 && ToIface2) {
if (Context.canAssignObjCInterfaces(ToIface2, ToIface1))
return ImplicitConversionSequence::Better;
else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2))
return ImplicitConversionSequence::Worse;
}
}
// -- conversion of B* to A* is better than conversion of C* to A*,
if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
if (IsDerivedFrom(FromPointee2, FromPointee1))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(FromPointee1, FromPointee2))
return ImplicitConversionSequence::Worse;
if (FromIface1 && FromIface2) {
if (Context.canAssignObjCInterfaces(FromIface1, FromIface2))
return ImplicitConversionSequence::Better;
else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1))
return ImplicitConversionSequence::Worse;
}
}
}
// Compare based on reference bindings.
if (SCS1.ReferenceBinding && SCS2.ReferenceBinding &&
SCS1.Second == ICK_Derived_To_Base) {
// -- binding of an expression of type C to a reference of type
// B& is better than binding an expression of type C to a
// reference of type A&,
if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() &&
ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) {
if (IsDerivedFrom(ToType1, ToType2))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(ToType2, ToType1))
return ImplicitConversionSequence::Worse;
}
// -- binding of an expression of type B to a reference of type
// A& is better than binding an expression of type C to a
// reference of type A&,
if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() &&
ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) {
if (IsDerivedFrom(FromType2, FromType1))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(FromType1, FromType2))
return ImplicitConversionSequence::Worse;
}
}
// FIXME: conversion of A::* to B::* is better than conversion of
// A::* to C::*,
// FIXME: conversion of B::* to C::* is better than conversion of
// A::* to C::*, and
if (SCS1.CopyConstructor && SCS2.CopyConstructor &&
SCS1.Second == ICK_Derived_To_Base) {
// -- conversion of C to B is better than conversion of C to A,
if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() &&
ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) {
if (IsDerivedFrom(ToType1, ToType2))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(ToType2, ToType1))
return ImplicitConversionSequence::Worse;
}
// -- conversion of B to A is better than conversion of C to A.
if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() &&
ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) {
if (IsDerivedFrom(FromType2, FromType1))
return ImplicitConversionSequence::Better;
else if (IsDerivedFrom(FromType1, FromType2))
return ImplicitConversionSequence::Worse;
}
}
return ImplicitConversionSequence::Indistinguishable;
}
/// TryCopyInitialization - Try to copy-initialize a value of type
/// ToType from the expression From. Return the implicit conversion
/// sequence required to pass this argument, which may be a bad
/// conversion sequence (meaning that the argument cannot be passed to
/// a parameter of this type). If @p SuppressUserConversions, then we
/// do not permit any user-defined conversion sequences. If @p ForceRValue,
/// then we treat @p From as an rvalue, even if it is an lvalue.
ImplicitConversionSequence
Sema::TryCopyInitialization(Expr *From, QualType ToType,
bool SuppressUserConversions, bool ForceRValue) {
if (ToType->isReferenceType()) {
ImplicitConversionSequence ICS;
CheckReferenceInit(From, ToType, &ICS, SuppressUserConversions,
/*AllowExplicit=*/false, ForceRValue);
return ICS;
} else {
return TryImplicitConversion(From, ToType, SuppressUserConversions,
ForceRValue);
}
}
/// PerformCopyInitialization - Copy-initialize an object of type @p ToType with
/// the expression @p From. Returns true (and emits a diagnostic) if there was
/// an error, returns false if the initialization succeeded. Elidable should
/// be true when the copy may be elided (C++ 12.8p15). Overload resolution works
/// differently in C++0x for this case.
bool Sema::PerformCopyInitialization(Expr *&From, QualType ToType,
const char* Flavor, bool Elidable) {
if (!getLangOptions().CPlusPlus) {
// In C, argument passing is the same as performing an assignment.
QualType FromType = From->getType();
AssignConvertType ConvTy =
CheckSingleAssignmentConstraints(ToType, From);
if (ConvTy != Compatible &&
CheckTransparentUnionArgumentConstraints(ToType, From) == Compatible)
ConvTy = Compatible;
return DiagnoseAssignmentResult(ConvTy, From->getLocStart(), ToType,
FromType, From, Flavor);
}
if (ToType->isReferenceType())
return CheckReferenceInit(From, ToType);
if (!PerformImplicitConversion(From, ToType, Flavor,
/*AllowExplicit=*/false, Elidable))
return false;
return Diag(From->getSourceRange().getBegin(),
diag::err_typecheck_convert_incompatible)
<< ToType << From->getType() << Flavor << From->getSourceRange();
}
/// TryObjectArgumentInitialization - Try to initialize the object
/// parameter of the given member function (@c Method) from the
/// expression @p From.
ImplicitConversionSequence
Sema::TryObjectArgumentInitialization(Expr *From, CXXMethodDecl *Method) {
QualType ClassType = Context.getTypeDeclType(Method->getParent());
unsigned MethodQuals = Method->getTypeQualifiers();
QualType ImplicitParamType = ClassType.getQualifiedType(MethodQuals);
// Set up the conversion sequence as a "bad" conversion, to allow us
// to exit early.
ImplicitConversionSequence ICS;
ICS.Standard.setAsIdentityConversion();
ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
// We need to have an object of class type.
QualType FromType = From->getType();
if (const PointerType *PT = FromType->getAs<PointerType>())
FromType = PT->getPointeeType();
assert(FromType->isRecordType());
// The implicit object parmeter is has the type "reference to cv X",
// where X is the class of which the function is a member
// (C++ [over.match.funcs]p4). However, when finding an implicit
// conversion sequence for the argument, we are not allowed to
// create temporaries or perform user-defined conversions
// (C++ [over.match.funcs]p5). We perform a simplified version of
// reference binding here, that allows class rvalues to bind to
// non-constant references.
// First check the qualifiers. We don't care about lvalue-vs-rvalue
// with the implicit object parameter (C++ [over.match.funcs]p5).
QualType FromTypeCanon = Context.getCanonicalType(FromType);
if (ImplicitParamType.getCVRQualifiers() != FromType.getCVRQualifiers() &&
!ImplicitParamType.isAtLeastAsQualifiedAs(FromType))
return ICS;
// Check that we have either the same type or a derived type. It
// affects the conversion rank.
QualType ClassTypeCanon = Context.getCanonicalType(ClassType);
if (ClassTypeCanon == FromTypeCanon.getUnqualifiedType())
ICS.Standard.Second = ICK_Identity;
else if (IsDerivedFrom(FromType, ClassType))
ICS.Standard.Second = ICK_Derived_To_Base;
else
return ICS;
// Success. Mark this as a reference binding.
ICS.ConversionKind = ImplicitConversionSequence::StandardConversion;
ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr();
ICS.Standard.ToTypePtr = ImplicitParamType.getAsOpaquePtr();
ICS.Standard.ReferenceBinding = true;
ICS.Standard.DirectBinding = true;
ICS.Standard.RRefBinding = false;
return ICS;
}
/// PerformObjectArgumentInitialization - Perform initialization of
/// the implicit object parameter for the given Method with the given
/// expression.
bool
Sema::PerformObjectArgumentInitialization(Expr *&From, CXXMethodDecl *Method) {
QualType FromRecordType, DestType;
QualType ImplicitParamRecordType =
Method->getThisType(Context)->getAs<PointerType>()->getPointeeType();
if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
FromRecordType = PT->getPointeeType();
DestType = Method->getThisType(Context);
} else {
FromRecordType = From->getType();
DestType = ImplicitParamRecordType;
}
ImplicitConversionSequence ICS
= TryObjectArgumentInitialization(From, Method);
if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion)
return Diag(From->getSourceRange().getBegin(),
diag::err_implicit_object_parameter_init)
<< ImplicitParamRecordType << FromRecordType << From->getSourceRange();
if (ICS.Standard.Second == ICK_Derived_To_Base &&
CheckDerivedToBaseConversion(FromRecordType,
ImplicitParamRecordType,
From->getSourceRange().getBegin(),
From->getSourceRange()))
return true;
ImpCastExprToType(From, DestType, CastExpr::CK_DerivedToBase,
/*isLvalue=*/true);
return false;
}
/// TryContextuallyConvertToBool - Attempt to contextually convert the
/// expression From to bool (C++0x [conv]p3).
ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) {
return TryImplicitConversion(From, Context.BoolTy, false, true);
}
/// PerformContextuallyConvertToBool - Perform a contextual conversion
/// of the expression From to bool (C++0x [conv]p3).
bool Sema::PerformContextuallyConvertToBool(Expr *&From) {
ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From);
if (!PerformImplicitConversion(From, Context.BoolTy, ICS, "converting"))
return false;
return Diag(From->getSourceRange().getBegin(),
diag::err_typecheck_bool_condition)
<< From->getType() << From->getSourceRange();
}
/// AddOverloadCandidate - Adds the given function to the set of
/// candidate functions, using the given function call arguments. If
/// @p SuppressUserConversions, then don't allow user-defined
/// conversions via constructors or conversion operators.
/// If @p ForceRValue, treat all arguments as rvalues. This is a slightly
/// hacky way to implement the overloading rules for elidable copy
/// initialization in C++0x (C++0x 12.8p15).
void
Sema::AddOverloadCandidate(FunctionDecl *Function,
Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
bool SuppressUserConversions,
bool ForceRValue)
{
const FunctionProtoType* Proto
= dyn_cast<FunctionProtoType>(Function->getType()->getAsFunctionType());
assert(Proto && "Functions without a prototype cannot be overloaded");
assert(!isa<CXXConversionDecl>(Function) &&
"Use AddConversionCandidate for conversion functions");
assert(!Function->getDescribedFunctionTemplate() &&
"Use AddTemplateOverloadCandidate for function templates");
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
if (!isa<CXXConstructorDecl>(Method)) {
// If we get here, it's because we're calling a member function
// that is named without a member access expression (e.g.,
// "this->f") that was either written explicitly or created
// implicitly. This can happen with a qualified call to a member
// function, e.g., X::f(). We use a NULL object as the implied
// object argument (C++ [over.call.func]p3).
AddMethodCandidate(Method, 0, Args, NumArgs, CandidateSet,
SuppressUserConversions, ForceRValue);
return;
}
// We treat a constructor like a non-member function, since its object
// argument doesn't participate in overload resolution.
}
// Add this candidate
CandidateSet.push_back(OverloadCandidate());
OverloadCandidate& Candidate = CandidateSet.back();
Candidate.Function = Function;
Candidate.Viable = true;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
unsigned NumArgsInProto = Proto->getNumArgs();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (NumArgs > NumArgsInProto && !Proto->isVariadic()) {
Candidate.Viable = false;
return;
}
// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Function->getMinRequiredArguments();
if (NumArgs < MinRequiredArgs) {
// Not enough arguments.
Candidate.Viable = false;
return;
}
// Determine the implicit conversion sequences for each of the
// arguments.
Candidate.Conversions.resize(NumArgs);
for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) {
if (ArgIdx < NumArgsInProto) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getArgType(ArgIdx);
Candidate.Conversions[ArgIdx]
= TryCopyInitialization(Args[ArgIdx], ParamType,
SuppressUserConversions, ForceRValue);
if (Candidate.Conversions[ArgIdx].ConversionKind
== ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
break;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to ""match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ArgIdx].ConversionKind
= ImplicitConversionSequence::EllipsisConversion;
}
}
}
/// \brief Add all of the function declarations in the given function set to
/// the overload canddiate set.
void Sema::AddFunctionCandidates(const FunctionSet &Functions,
Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
bool SuppressUserConversions) {
for (FunctionSet::const_iterator F = Functions.begin(),
FEnd = Functions.end();
F != FEnd; ++F) {
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*F))
AddOverloadCandidate(FD, Args, NumArgs, CandidateSet,
SuppressUserConversions);
else
AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*F),
/*FIXME: explicit args */false, 0, 0,
Args, NumArgs, CandidateSet,
SuppressUserConversions);
}
}
/// AddMethodCandidate - Adds the given C++ member function to the set
/// of candidate functions, using the given function call arguments
/// and the object argument (@c Object). For example, in a call
/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
/// allow user-defined conversions via constructors or conversion
/// operators. If @p ForceRValue, treat all arguments as rvalues. This is
/// a slightly hacky way to implement the overloading rules for elidable copy
/// initialization in C++0x (C++0x 12.8p15).
void
Sema::AddMethodCandidate(CXXMethodDecl *Method, Expr *Object,
Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
bool SuppressUserConversions, bool ForceRValue)
{
const FunctionProtoType* Proto
= dyn_cast<FunctionProtoType>(Method->getType()->getAsFunctionType());
assert(Proto && "Methods without a prototype cannot be overloaded");
assert(!isa<CXXConversionDecl>(Method) &&
"Use AddConversionCandidate for conversion functions");
assert(!isa<CXXConstructorDecl>(Method) &&
"Use AddOverloadCandidate for constructors");
// Add this candidate
CandidateSet.push_back(OverloadCandidate());
OverloadCandidate& Candidate = CandidateSet.back();
Candidate.Function = Method;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
unsigned NumArgsInProto = Proto->getNumArgs();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (NumArgs > NumArgsInProto && !Proto->isVariadic()) {
Candidate.Viable = false;
return;
}
// (C++ 13.3.2p2): A candidate function having more than m parameters
// is viable only if the (m+1)st parameter has a default argument
// (8.3.6). For the purposes of overload resolution, the
// parameter list is truncated on the right, so that there are
// exactly m parameters.
unsigned MinRequiredArgs = Method->getMinRequiredArguments();
if (NumArgs < MinRequiredArgs) {
// Not enough arguments.
Candidate.Viable = false;
return;
}
Candidate.Viable = true;
Candidate.Conversions.resize(NumArgs + 1);
if (Method->isStatic() || !Object)
// The implicit object argument is ignored.
Candidate.IgnoreObjectArgument = true;
else {
// Determine the implicit conversion sequence for the object
// parameter.
Candidate.Conversions[0] = TryObjectArgumentInitialization(Object, Method);
if (Candidate.Conversions[0].ConversionKind
== ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
return;
}
}
// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) {
if (ArgIdx < NumArgsInProto) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getArgType(ArgIdx);
Candidate.Conversions[ArgIdx + 1]
= TryCopyInitialization(Args[ArgIdx], ParamType,
SuppressUserConversions, ForceRValue);
if (Candidate.Conversions[ArgIdx + 1].ConversionKind
== ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
break;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to ""match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ArgIdx + 1].ConversionKind
= ImplicitConversionSequence::EllipsisConversion;
}
}
}
/// \brief Add a C++ member function template as a candidate to the candidate
/// set, using template argument deduction to produce an appropriate member
/// function template specialization.
void
Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
bool HasExplicitTemplateArgs,
const TemplateArgument *ExplicitTemplateArgs,
unsigned NumExplicitTemplateArgs,
Expr *Object, Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
bool SuppressUserConversions,
bool ForceRValue) {
// C++ [over.match.funcs]p7:
// In each case where a candidate is a function template, candidate
// function template specializations are generated using template argument
// deduction (14.8.3, 14.8.2). Those candidates are then handled as
// candidate functions in the usual way.113) A given name can refer to one
// or more function templates and also to a set of overloaded non-template
// functions. In such a case, the candidate functions generated from each
// function template are combined with the set of non-template candidate
// functions.
TemplateDeductionInfo Info(Context);
FunctionDecl *Specialization = 0;
if (TemplateDeductionResult Result
= DeduceTemplateArguments(MethodTmpl, HasExplicitTemplateArgs,
ExplicitTemplateArgs, NumExplicitTemplateArgs,
Args, NumArgs, Specialization, Info)) {
// FIXME: Record what happened with template argument deduction, so
// that we can give the user a beautiful diagnostic.
(void)Result;
return;
}
// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing member function template specialization?");
assert(isa<CXXMethodDecl>(Specialization) &&
"Specialization is not a member function?");
AddMethodCandidate(cast<CXXMethodDecl>(Specialization), Object, Args, NumArgs,
CandidateSet, SuppressUserConversions, ForceRValue);
}
/// \brief Add a C++ function template specialization as a candidate
/// in the candidate set, using template argument deduction to produce
/// an appropriate function template specialization.
void
Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate,
bool HasExplicitTemplateArgs,
const TemplateArgument *ExplicitTemplateArgs,
unsigned NumExplicitTemplateArgs,
Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
bool SuppressUserConversions,
bool ForceRValue) {
// C++ [over.match.funcs]p7:
// In each case where a candidate is a function template, candidate
// function template specializations are generated using template argument
// deduction (14.8.3, 14.8.2). Those candidates are then handled as
// candidate functions in the usual way.113) A given name can refer to one
// or more function templates and also to a set of overloaded non-template
// functions. In such a case, the candidate functions generated from each
// function template are combined with the set of non-template candidate
// functions.
TemplateDeductionInfo Info(Context);
FunctionDecl *Specialization = 0;
if (TemplateDeductionResult Result
= DeduceTemplateArguments(FunctionTemplate, HasExplicitTemplateArgs,
ExplicitTemplateArgs, NumExplicitTemplateArgs,
Args, NumArgs, Specialization, Info)) {
// FIXME: Record what happened with template argument deduction, so
// that we can give the user a beautiful diagnostic.
(void)Result;
return;
}
// Add the function template specialization produced by template argument
// deduction as a candidate.
assert(Specialization && "Missing function template specialization?");
AddOverloadCandidate(Specialization, Args, NumArgs, CandidateSet,
SuppressUserConversions, ForceRValue);
}
/// AddConversionCandidate - Add a C++ conversion function as a
/// candidate in the candidate set (C++ [over.match.conv],
/// C++ [over.match.copy]). From is the expression we're converting from,
/// and ToType is the type that we're eventually trying to convert to
/// (which may or may not be the same type as the type that the
/// conversion function produces).
void
Sema::AddConversionCandidate(CXXConversionDecl *Conversion,
Expr *From, QualType ToType,
OverloadCandidateSet& CandidateSet) {
assert(!Conversion->getDescribedFunctionTemplate() &&
"Conversion function templates use AddTemplateConversionCandidate");
// Add this candidate
CandidateSet.push_back(OverloadCandidate());
OverloadCandidate& Candidate = CandidateSet.back();
Candidate.Function = Conversion;
Candidate.IsSurrogate = false;
Candidate.IgnoreObjectArgument = false;
Candidate.FinalConversion.setAsIdentityConversion();
Candidate.FinalConversion.FromTypePtr
= Conversion->getConversionType().getAsOpaquePtr();
Candidate.FinalConversion.ToTypePtr = ToType.getAsOpaquePtr();
// Determine the implicit conversion sequence for the implicit
// object parameter.
Candidate.Viable = true;
Candidate.Conversions.resize(1);
Candidate.Conversions[0] = TryObjectArgumentInitialization(From, Conversion);
if (Candidate.Conversions[0].ConversionKind
== ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
return;
}
// To determine what the conversion from the result of calling the
// conversion function to the type we're eventually trying to
// convert to (ToType), we need to synthesize a call to the
// conversion function and attempt copy initialization from it. This
// makes sure that we get the right semantics with respect to
// lvalues/rvalues and the type. Fortunately, we can allocate this
// call on the stack and we don't need its arguments to be
// well-formed.
DeclRefExpr ConversionRef(Conversion, Conversion->getType(),
SourceLocation());
ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()),
CastExpr::CK_Unknown,
&ConversionRef, false);
// Note that it is safe to allocate CallExpr on the stack here because
// there are 0 arguments (i.e., nothing is allocated using ASTContext's
// allocator).
CallExpr Call(Context, &ConversionFn, 0, 0,
Conversion->getConversionType().getNonReferenceType(),
SourceLocation());
ImplicitConversionSequence ICS = TryCopyInitialization(&Call, ToType, true);
switch (ICS.ConversionKind) {
case ImplicitConversionSequence::StandardConversion:
Candidate.FinalConversion = ICS.Standard;
break;
case ImplicitConversionSequence::BadConversion:
Candidate.Viable = false;
break;
default:
assert(false &&
"Can only end up with a standard conversion sequence or failure");
}
}
/// \brief Adds a conversion function template specialization
/// candidate to the overload set, using template argument deduction
/// to deduce the template arguments of the conversion function
/// template from the type that we are converting to (C++
/// [temp.deduct.conv]).
void
Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate,
Expr *From, QualType ToType,
OverloadCandidateSet &CandidateSet) {
assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&
"Only conversion function templates permitted here");
TemplateDeductionInfo Info(Context);
CXXConversionDecl *Specialization = 0;
if (TemplateDeductionResult Result
= DeduceTemplateArguments(FunctionTemplate, ToType,
Specialization, Info)) {
// FIXME: Record what happened with template argument deduction, so
// that we can give the user a beautiful diagnostic.
(void)Result;
return;
}
// Add the conversion function template specialization produced by
// template argument deduction as a candidate.
assert(Specialization && "Missing function template specialization?");
AddConversionCandidate(Specialization, From, ToType, CandidateSet);
}
/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
/// converts the given @c Object to a function pointer via the
/// conversion function @c Conversion, and then attempts to call it
/// with the given arguments (C++ [over.call.object]p2-4). Proto is
/// the type of function that we'll eventually be calling.
void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
const FunctionProtoType *Proto,
Expr *Object, Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet) {
CandidateSet.push_back(OverloadCandidate());
OverloadCandidate& Candidate = CandidateSet.back();
Candidate.Function = 0;
Candidate.Surrogate = Conversion;
Candidate.Viable = true;
Candidate.IsSurrogate = true;
Candidate.IgnoreObjectArgument = false;
Candidate.Conversions.resize(NumArgs + 1);
// Determine the implicit conversion sequence for the implicit
// object parameter.
ImplicitConversionSequence ObjectInit
= TryObjectArgumentInitialization(Object, Conversion);
if (ObjectInit.ConversionKind == ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
return;
}
// The first conversion is actually a user-defined conversion whose
// first conversion is ObjectInit's standard conversion (which is
// effectively a reference binding). Record it as such.
Candidate.Conversions[0].ConversionKind
= ImplicitConversionSequence::UserDefinedConversion;
Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
Candidate.Conversions[0].UserDefined.After
= Candidate.Conversions[0].UserDefined.Before;
Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();
// Find the
unsigned NumArgsInProto = Proto->getNumArgs();
// (C++ 13.3.2p2): A candidate function having fewer than m
// parameters is viable only if it has an ellipsis in its parameter
// list (8.3.5).
if (NumArgs > NumArgsInProto && !Proto->isVariadic()) {
Candidate.Viable = false;
return;
}
// Function types don't have any default arguments, so just check if
// we have enough arguments.
if (NumArgs < NumArgsInProto) {
// Not enough arguments.
Candidate.Viable = false;
return;
}
// Determine the implicit conversion sequences for each of the
// arguments.
for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) {
if (ArgIdx < NumArgsInProto) {
// (C++ 13.3.2p3): for F to be a viable function, there shall
// exist for each argument an implicit conversion sequence
// (13.3.3.1) that converts that argument to the corresponding
// parameter of F.
QualType ParamType = Proto->getArgType(ArgIdx);
Candidate.Conversions[ArgIdx + 1]
= TryCopyInitialization(Args[ArgIdx], ParamType,
/*SuppressUserConversions=*/false);
if (Candidate.Conversions[ArgIdx + 1].ConversionKind
== ImplicitConversionSequence::BadConversion) {
Candidate.Viable = false;
break;
}
} else {
// (C++ 13.3.2p2): For the purposes of overload resolution, any
// argument for which there is no corresponding parameter is
// considered to ""match the ellipsis" (C+ 13.3.3.1.3).
Candidate.Conversions[ArgIdx + 1].ConversionKind
= ImplicitConversionSequence::EllipsisConversion;
}
}
}
// FIXME: This will eventually be removed, once we've migrated all of the
// operator overloading logic over to the scheme used by binary operators, which
// works for template instantiation.
void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S,
SourceLocation OpLoc,
Expr **Args, unsigned NumArgs,
OverloadCandidateSet& CandidateSet,
SourceRange OpRange) {
FunctionSet Functions;
QualType T1 = Args[0]->getType();
QualType T2;
if (NumArgs > 1)
T2 = Args[1]->getType();
DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
if (S)
LookupOverloadedOperatorName(Op, S, T1, T2, Functions);
ArgumentDependentLookup(OpName, Args, NumArgs, Functions);
AddFunctionCandidates(Functions, Args, NumArgs, CandidateSet);
AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange);
AddBuiltinOperatorCandidates(Op, Args, NumArgs, CandidateSet);
}
/// \brief Add overload candidates for overloaded operators that are
/// member functions.
///