diff options
Diffstat (limited to 'contrib/llvm/tools/clang/lib/Sema/SemaOverload.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Sema/SemaOverload.cpp | 13859 |
1 files changed, 13859 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaOverload.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaOverload.cpp new file mode 100644 index 000000000000..52be0598fbc0 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Sema/SemaOverload.cpp @@ -0,0 +1,13859 @@ +//===--- SemaOverload.cpp - C++ Overloading -------------------------------===// +// +// 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 "clang/Sema/Overload.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/Expr.h" +#include "clang/AST/ExprCXX.h" +#include "clang/AST/ExprObjC.h" +#include "clang/AST/TypeOrdering.h" +#include "clang/Basic/Diagnostic.h" +#include "clang/Basic/DiagnosticOptions.h" +#include "clang/Basic/PartialDiagnostic.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/Sema/Initialization.h" +#include "clang/Sema/Lookup.h" +#include "clang/Sema/SemaInternal.h" +#include "clang/Sema/Template.h" +#include "clang/Sema/TemplateDeduction.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/Optional.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallString.h" +#include <algorithm> +#include <cstdlib> + +using namespace clang; +using namespace sema; + +static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) { + return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) { + return P->hasAttr<PassObjectSizeAttr>(); + }); +} + +/// A convenience routine for creating a decayed reference to a function. +static ExprResult +CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl, + const Expr *Base, bool HadMultipleCandidates, + SourceLocation Loc = SourceLocation(), + const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){ + if (S.DiagnoseUseOfDecl(FoundDecl, Loc)) + return ExprError(); + // If FoundDecl is different from Fn (such as if one is a template + // and the other a specialization), make sure DiagnoseUseOfDecl is + // called on both. + // FIXME: This would be more comprehensively addressed by modifying + // DiagnoseUseOfDecl to accept both the FoundDecl and the decl + // being used. + if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc)) + return ExprError(); + if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>()) + S.ResolveExceptionSpec(Loc, FPT); + DeclRefExpr *DRE = new (S.Context) + DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo); + if (HadMultipleCandidates) + DRE->setHadMultipleCandidates(true); + + S.MarkDeclRefReferenced(DRE, Base); + return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()), + CK_FunctionToPointerDecay); +} + +static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle, + bool AllowObjCWritebackConversion); + +static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From, + QualType &ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle); +static OverloadingResult +IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType, + UserDefinedConversionSequence& User, + OverloadCandidateSet& Conversions, + bool AllowExplicit, + bool AllowObjCConversionOnExplicit); + + +static ImplicitConversionSequence::CompareKind +CompareStandardConversionSequences(Sema &S, SourceLocation Loc, + const StandardConversionSequence& SCS1, + const StandardConversionSequence& SCS2); + +static ImplicitConversionSequence::CompareKind +CompareQualificationConversions(Sema &S, + const StandardConversionSequence& SCS1, + const StandardConversionSequence& SCS2); + +static ImplicitConversionSequence::CompareKind +CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc, + const StandardConversionSequence& SCS1, + const StandardConversionSequence& SCS2); + +/// GetConversionRank - Retrieve the implicit conversion rank +/// corresponding to the given implicit conversion kind. +ImplicitConversionRank clang::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_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, + ICR_OCL_Scalar_Widening, + ICR_Complex_Real_Conversion, + ICR_Conversion, + ICR_Conversion, + ICR_Writeback_Conversion, + ICR_Exact_Match, // NOTE(gbiv): This may not be completely right -- + // it was omitted by the patch that added + // ICK_Zero_Event_Conversion + ICR_C_Conversion, + ICR_C_Conversion_Extension + }; + return Rank[(int)Kind]; +} + +/// GetImplicitConversionName - Return the name of this kind of +/// implicit conversion. +static const char* GetImplicitConversionName(ImplicitConversionKind Kind) { + static const char* const Name[(int)ICK_Num_Conversion_Kinds] = { + "No conversion", + "Lvalue-to-rvalue", + "Array-to-pointer", + "Function-to-pointer", + "Function pointer conversion", + "Qualification", + "Integral promotion", + "Floating point promotion", + "Complex promotion", + "Integral conversion", + "Floating conversion", + "Complex conversion", + "Floating-integral conversion", + "Pointer conversion", + "Pointer-to-member conversion", + "Boolean conversion", + "Compatible-types conversion", + "Derived-to-base conversion", + "Vector conversion", + "Vector splat", + "Complex-real conversion", + "Block Pointer conversion", + "Transparent Union Conversion", + "Writeback conversion", + "OpenCL Zero Event Conversion", + "C specific type conversion", + "Incompatible pointer 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; + DeprecatedStringLiteralToCharPtr = false; + QualificationIncludesObjCLifetime = false; + ReferenceBinding = false; + DirectBinding = false; + IsLvalueReference = true; + BindsToFunctionLvalue = false; + BindsToRvalue = false; + BindsImplicitObjectArgumentWithoutRefQualifier = false; + ObjCLifetimeConversionBinding = false; + CopyConstructor = nullptr; +} + +/// 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 { + // 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 (getToType(1)->isBooleanType() && + (getFromType()->isPointerType() || + getFromType()->isMemberPointerType() || + getFromType()->isObjCObjectPointerType() || + getFromType()->isBlockPointerType() || + getFromType()->isNullPtrType() || + 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 = getFromType(); + QualType ToType = getToType(1); + + // 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 && FromType->isAnyPointerType()) + if (const PointerType* ToPtrType = ToType->getAs<PointerType>()) + return ToPtrType->getPointeeType()->isVoidType(); + + return false; +} + +/// Skip any implicit casts which could be either part of a narrowing conversion +/// or after one in an implicit conversion. +static const Expr *IgnoreNarrowingConversion(const Expr *Converted) { + while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Converted)) { + switch (ICE->getCastKind()) { + case CK_NoOp: + case CK_IntegralCast: + case CK_IntegralToBoolean: + case CK_IntegralToFloating: + case CK_BooleanToSignedIntegral: + case CK_FloatingToIntegral: + case CK_FloatingToBoolean: + case CK_FloatingCast: + Converted = ICE->getSubExpr(); + continue; + + default: + return Converted; + } + } + + return Converted; +} + +/// Check if this standard conversion sequence represents a narrowing +/// conversion, according to C++11 [dcl.init.list]p7. +/// +/// \param Ctx The AST context. +/// \param Converted The result of applying this standard conversion sequence. +/// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the +/// value of the expression prior to the narrowing conversion. +/// \param ConstantType If this is an NK_Constant_Narrowing conversion, the +/// type of the expression prior to the narrowing conversion. +/// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions +/// from floating point types to integral types should be ignored. +NarrowingKind StandardConversionSequence::getNarrowingKind( + ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue, + QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const { + assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++"); + + // C++11 [dcl.init.list]p7: + // A narrowing conversion is an implicit conversion ... + QualType FromType = getToType(0); + QualType ToType = getToType(1); + + // A conversion to an enumeration type is narrowing if the conversion to + // the underlying type is narrowing. This only arises for expressions of + // the form 'Enum{init}'. + if (auto *ET = ToType->getAs<EnumType>()) + ToType = ET->getDecl()->getIntegerType(); + + switch (Second) { + // 'bool' is an integral type; dispatch to the right place to handle it. + case ICK_Boolean_Conversion: + if (FromType->isRealFloatingType()) + goto FloatingIntegralConversion; + if (FromType->isIntegralOrUnscopedEnumerationType()) + goto IntegralConversion; + // Boolean conversions can be from pointers and pointers to members + // [conv.bool], and those aren't considered narrowing conversions. + return NK_Not_Narrowing; + + // -- from a floating-point type to an integer type, or + // + // -- from an integer type or unscoped enumeration type to a floating-point + // type, except where the source is a constant expression and the actual + // value after conversion will fit into the target type and will produce + // the original value when converted back to the original type, or + case ICK_Floating_Integral: + FloatingIntegralConversion: + if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) { + return NK_Type_Narrowing; + } else if (FromType->isIntegralOrUnscopedEnumerationType() && + ToType->isRealFloatingType()) { + if (IgnoreFloatToIntegralConversion) + return NK_Not_Narrowing; + llvm::APSInt IntConstantValue; + const Expr *Initializer = IgnoreNarrowingConversion(Converted); + assert(Initializer && "Unknown conversion expression"); + + // If it's value-dependent, we can't tell whether it's narrowing. + if (Initializer->isValueDependent()) + return NK_Dependent_Narrowing; + + if (Initializer->isIntegerConstantExpr(IntConstantValue, Ctx)) { + // Convert the integer to the floating type. + llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType)); + Result.convertFromAPInt(IntConstantValue, IntConstantValue.isSigned(), + llvm::APFloat::rmNearestTiesToEven); + // And back. + llvm::APSInt ConvertedValue = IntConstantValue; + bool ignored; + Result.convertToInteger(ConvertedValue, + llvm::APFloat::rmTowardZero, &ignored); + // If the resulting value is different, this was a narrowing conversion. + if (IntConstantValue != ConvertedValue) { + ConstantValue = APValue(IntConstantValue); + ConstantType = Initializer->getType(); + return NK_Constant_Narrowing; + } + } else { + // Variables are always narrowings. + return NK_Variable_Narrowing; + } + } + return NK_Not_Narrowing; + + // -- from long double to double or float, or from double to float, except + // where the source is a constant expression and the actual value after + // conversion is within the range of values that can be represented (even + // if it cannot be represented exactly), or + case ICK_Floating_Conversion: + if (FromType->isRealFloatingType() && ToType->isRealFloatingType() && + Ctx.getFloatingTypeOrder(FromType, ToType) == 1) { + // FromType is larger than ToType. + const Expr *Initializer = IgnoreNarrowingConversion(Converted); + + // If it's value-dependent, we can't tell whether it's narrowing. + if (Initializer->isValueDependent()) + return NK_Dependent_Narrowing; + + if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) { + // Constant! + assert(ConstantValue.isFloat()); + llvm::APFloat FloatVal = ConstantValue.getFloat(); + // Convert the source value into the target type. + bool ignored; + llvm::APFloat::opStatus ConvertStatus = FloatVal.convert( + Ctx.getFloatTypeSemantics(ToType), + llvm::APFloat::rmNearestTiesToEven, &ignored); + // If there was no overflow, the source value is within the range of + // values that can be represented. + if (ConvertStatus & llvm::APFloat::opOverflow) { + ConstantType = Initializer->getType(); + return NK_Constant_Narrowing; + } + } else { + return NK_Variable_Narrowing; + } + } + return NK_Not_Narrowing; + + // -- from an integer type or unscoped enumeration type to an integer type + // that cannot represent all the values of the original type, except where + // the source is a constant expression and the actual value after + // conversion will fit into the target type and will produce the original + // value when converted back to the original type. + case ICK_Integral_Conversion: + IntegralConversion: { + assert(FromType->isIntegralOrUnscopedEnumerationType()); + assert(ToType->isIntegralOrUnscopedEnumerationType()); + const bool FromSigned = FromType->isSignedIntegerOrEnumerationType(); + const unsigned FromWidth = Ctx.getIntWidth(FromType); + const bool ToSigned = ToType->isSignedIntegerOrEnumerationType(); + const unsigned ToWidth = Ctx.getIntWidth(ToType); + + if (FromWidth > ToWidth || + (FromWidth == ToWidth && FromSigned != ToSigned) || + (FromSigned && !ToSigned)) { + // Not all values of FromType can be represented in ToType. + llvm::APSInt InitializerValue; + const Expr *Initializer = IgnoreNarrowingConversion(Converted); + + // If it's value-dependent, we can't tell whether it's narrowing. + if (Initializer->isValueDependent()) + return NK_Dependent_Narrowing; + + if (!Initializer->isIntegerConstantExpr(InitializerValue, Ctx)) { + // Such conversions on variables are always narrowing. + return NK_Variable_Narrowing; + } + bool Narrowing = false; + if (FromWidth < ToWidth) { + // Negative -> unsigned is narrowing. Otherwise, more bits is never + // narrowing. + if (InitializerValue.isSigned() && InitializerValue.isNegative()) + Narrowing = true; + } else { + // Add a bit to the InitializerValue so we don't have to worry about + // signed vs. unsigned comparisons. + InitializerValue = InitializerValue.extend( + InitializerValue.getBitWidth() + 1); + // Convert the initializer to and from the target width and signed-ness. + llvm::APSInt ConvertedValue = InitializerValue; + ConvertedValue = ConvertedValue.trunc(ToWidth); + ConvertedValue.setIsSigned(ToSigned); + ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth()); + ConvertedValue.setIsSigned(InitializerValue.isSigned()); + // If the result is different, this was a narrowing conversion. + if (ConvertedValue != InitializerValue) + Narrowing = true; + } + if (Narrowing) { + ConstantType = Initializer->getType(); + ConstantValue = APValue(InitializerValue); + return NK_Constant_Narrowing; + } + } + return NK_Not_Narrowing; + } + + default: + // Other kinds of conversions are not narrowings. + return NK_Not_Narrowing; + } +} + +/// dump - Print this standard conversion sequence to standard +/// error. Useful for debugging overloading issues. +LLVM_DUMP_METHOD void StandardConversionSequence::dump() const { + raw_ostream &OS = llvm::errs(); + bool PrintedSomething = false; + if (First != ICK_Identity) { + OS << GetImplicitConversionName(First); + PrintedSomething = true; + } + + if (Second != ICK_Identity) { + if (PrintedSomething) { + OS << " -> "; + } + OS << GetImplicitConversionName(Second); + + if (CopyConstructor) { + OS << " (by copy constructor)"; + } else if (DirectBinding) { + OS << " (direct reference binding)"; + } else if (ReferenceBinding) { + OS << " (reference binding)"; + } + PrintedSomething = true; + } + + if (Third != ICK_Identity) { + if (PrintedSomething) { + OS << " -> "; + } + OS << GetImplicitConversionName(Third); + PrintedSomething = true; + } + + if (!PrintedSomething) { + OS << "No conversions required"; + } +} + +/// dump - Print this user-defined conversion sequence to standard +/// error. Useful for debugging overloading issues. +void UserDefinedConversionSequence::dump() const { + raw_ostream &OS = llvm::errs(); + if (Before.First || Before.Second || Before.Third) { + Before.dump(); + OS << " -> "; + } + if (ConversionFunction) + OS << '\'' << *ConversionFunction << '\''; + else + OS << "aggregate initialization"; + if (After.First || After.Second || After.Third) { + OS << " -> "; + After.dump(); + } +} + +/// dump - Print this implicit conversion sequence to standard +/// error. Useful for debugging overloading issues. +void ImplicitConversionSequence::dump() const { + raw_ostream &OS = llvm::errs(); + if (isStdInitializerListElement()) + OS << "Worst std::initializer_list element conversion: "; + switch (ConversionKind) { + case StandardConversion: + OS << "Standard conversion: "; + Standard.dump(); + break; + case UserDefinedConversion: + OS << "User-defined conversion: "; + UserDefined.dump(); + break; + case EllipsisConversion: + OS << "Ellipsis conversion"; + break; + case AmbiguousConversion: + OS << "Ambiguous conversion"; + break; + case BadConversion: + OS << "Bad conversion"; + break; + } + + OS << "\n"; +} + +void AmbiguousConversionSequence::construct() { + new (&conversions()) ConversionSet(); +} + +void AmbiguousConversionSequence::destruct() { + conversions().~ConversionSet(); +} + +void +AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) { + FromTypePtr = O.FromTypePtr; + ToTypePtr = O.ToTypePtr; + new (&conversions()) ConversionSet(O.conversions()); +} + +namespace { + // Structure used by DeductionFailureInfo to store + // template argument information. + struct DFIArguments { + TemplateArgument FirstArg; + TemplateArgument SecondArg; + }; + // Structure used by DeductionFailureInfo to store + // template parameter and template argument information. + struct DFIParamWithArguments : DFIArguments { + TemplateParameter Param; + }; + // Structure used by DeductionFailureInfo to store template argument + // information and the index of the problematic call argument. + struct DFIDeducedMismatchArgs : DFIArguments { + TemplateArgumentList *TemplateArgs; + unsigned CallArgIndex; + }; +} + +/// Convert from Sema's representation of template deduction information +/// to the form used in overload-candidate information. +DeductionFailureInfo +clang::MakeDeductionFailureInfo(ASTContext &Context, + Sema::TemplateDeductionResult TDK, + TemplateDeductionInfo &Info) { + DeductionFailureInfo Result; + Result.Result = static_cast<unsigned>(TDK); + Result.HasDiagnostic = false; + switch (TDK) { + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_MiscellaneousDeductionFailure: + case Sema::TDK_CUDATargetMismatch: + Result.Data = nullptr; + break; + + case Sema::TDK_Incomplete: + case Sema::TDK_InvalidExplicitArguments: + Result.Data = Info.Param.getOpaqueValue(); + break; + + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: { + // FIXME: Should allocate from normal heap so that we can free this later. + auto *Saved = new (Context) DFIDeducedMismatchArgs; + Saved->FirstArg = Info.FirstArg; + Saved->SecondArg = Info.SecondArg; + Saved->TemplateArgs = Info.take(); + Saved->CallArgIndex = Info.CallArgIndex; + Result.Data = Saved; + break; + } + + case Sema::TDK_NonDeducedMismatch: { + // FIXME: Should allocate from normal heap so that we can free this later. + DFIArguments *Saved = new (Context) DFIArguments; + Saved->FirstArg = Info.FirstArg; + Saved->SecondArg = Info.SecondArg; + Result.Data = Saved; + break; + } + + case Sema::TDK_IncompletePack: + // FIXME: It's slightly wasteful to allocate two TemplateArguments for this. + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: { + // FIXME: Should allocate from normal heap so that we can free this later. + DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments; + Saved->Param = Info.Param; + Saved->FirstArg = Info.FirstArg; + Saved->SecondArg = Info.SecondArg; + Result.Data = Saved; + break; + } + + case Sema::TDK_SubstitutionFailure: + Result.Data = Info.take(); + if (Info.hasSFINAEDiagnostic()) { + PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt( + SourceLocation(), PartialDiagnostic::NullDiagnostic()); + Info.takeSFINAEDiagnostic(*Diag); + Result.HasDiagnostic = true; + } + break; + + case Sema::TDK_Success: + case Sema::TDK_NonDependentConversionFailure: + llvm_unreachable("not a deduction failure"); + } + + return Result; +} + +void DeductionFailureInfo::Destroy() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_Success: + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_Incomplete: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_InvalidExplicitArguments: + case Sema::TDK_CUDATargetMismatch: + case Sema::TDK_NonDependentConversionFailure: + break; + + case Sema::TDK_IncompletePack: + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + case Sema::TDK_NonDeducedMismatch: + // FIXME: Destroy the data? + Data = nullptr; + break; + + case Sema::TDK_SubstitutionFailure: + // FIXME: Destroy the template argument list? + Data = nullptr; + if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) { + Diag->~PartialDiagnosticAt(); + HasDiagnostic = false; + } + break; + + // Unhandled + case Sema::TDK_MiscellaneousDeductionFailure: + break; + } +} + +PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() { + if (HasDiagnostic) + return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic)); + return nullptr; +} + +TemplateParameter DeductionFailureInfo::getTemplateParameter() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_Success: + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_SubstitutionFailure: + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + case Sema::TDK_NonDeducedMismatch: + case Sema::TDK_CUDATargetMismatch: + case Sema::TDK_NonDependentConversionFailure: + return TemplateParameter(); + + case Sema::TDK_Incomplete: + case Sema::TDK_InvalidExplicitArguments: + return TemplateParameter::getFromOpaqueValue(Data); + + case Sema::TDK_IncompletePack: + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: + return static_cast<DFIParamWithArguments*>(Data)->Param; + + // Unhandled + case Sema::TDK_MiscellaneousDeductionFailure: + break; + } + + return TemplateParameter(); +} + +TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_Success: + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_Incomplete: + case Sema::TDK_IncompletePack: + case Sema::TDK_InvalidExplicitArguments: + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: + case Sema::TDK_NonDeducedMismatch: + case Sema::TDK_CUDATargetMismatch: + case Sema::TDK_NonDependentConversionFailure: + return nullptr; + + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs; + + case Sema::TDK_SubstitutionFailure: + return static_cast<TemplateArgumentList*>(Data); + + // Unhandled + case Sema::TDK_MiscellaneousDeductionFailure: + break; + } + + return nullptr; +} + +const TemplateArgument *DeductionFailureInfo::getFirstArg() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_Success: + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_Incomplete: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_InvalidExplicitArguments: + case Sema::TDK_SubstitutionFailure: + case Sema::TDK_CUDATargetMismatch: + case Sema::TDK_NonDependentConversionFailure: + return nullptr; + + case Sema::TDK_IncompletePack: + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + case Sema::TDK_NonDeducedMismatch: + return &static_cast<DFIArguments*>(Data)->FirstArg; + + // Unhandled + case Sema::TDK_MiscellaneousDeductionFailure: + break; + } + + return nullptr; +} + +const TemplateArgument *DeductionFailureInfo::getSecondArg() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_Success: + case Sema::TDK_Invalid: + case Sema::TDK_InstantiationDepth: + case Sema::TDK_Incomplete: + case Sema::TDK_IncompletePack: + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + case Sema::TDK_InvalidExplicitArguments: + case Sema::TDK_SubstitutionFailure: + case Sema::TDK_CUDATargetMismatch: + case Sema::TDK_NonDependentConversionFailure: + return nullptr; + + case Sema::TDK_Inconsistent: + case Sema::TDK_Underqualified: + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + case Sema::TDK_NonDeducedMismatch: + return &static_cast<DFIArguments*>(Data)->SecondArg; + + // Unhandled + case Sema::TDK_MiscellaneousDeductionFailure: + break; + } + + return nullptr; +} + +llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() { + switch (static_cast<Sema::TemplateDeductionResult>(Result)) { + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex; + + default: + return llvm::None; + } +} + +void OverloadCandidateSet::destroyCandidates() { + for (iterator i = begin(), e = end(); i != e; ++i) { + for (auto &C : i->Conversions) + C.~ImplicitConversionSequence(); + if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction) + i->DeductionFailure.Destroy(); + } +} + +void OverloadCandidateSet::clear(CandidateSetKind CSK) { + destroyCandidates(); + SlabAllocator.Reset(); + NumInlineBytesUsed = 0; + Candidates.clear(); + Functions.clear(); + Kind = CSK; +} + +namespace { + class UnbridgedCastsSet { + struct Entry { + Expr **Addr; + Expr *Saved; + }; + SmallVector<Entry, 2> Entries; + + public: + void save(Sema &S, Expr *&E) { + assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast)); + Entry entry = { &E, E }; + Entries.push_back(entry); + E = S.stripARCUnbridgedCast(E); + } + + void restore() { + for (SmallVectorImpl<Entry>::iterator + i = Entries.begin(), e = Entries.end(); i != e; ++i) + *i->Addr = i->Saved; + } + }; +} + +/// checkPlaceholderForOverload - Do any interesting placeholder-like +/// preprocessing on the given expression. +/// +/// \param unbridgedCasts a collection to which to add unbridged casts; +/// without this, they will be immediately diagnosed as errors +/// +/// Return true on unrecoverable error. +static bool +checkPlaceholderForOverload(Sema &S, Expr *&E, + UnbridgedCastsSet *unbridgedCasts = nullptr) { + if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) { + // We can't handle overloaded expressions here because overload + // resolution might reasonably tweak them. + if (placeholder->getKind() == BuiltinType::Overload) return false; + + // If the context potentially accepts unbridged ARC casts, strip + // the unbridged cast and add it to the collection for later restoration. + if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast && + unbridgedCasts) { + unbridgedCasts->save(S, E); + return false; + } + + // Go ahead and check everything else. + ExprResult result = S.CheckPlaceholderExpr(E); + if (result.isInvalid()) + return true; + + E = result.get(); + return false; + } + + // Nothing to do. + return false; +} + +/// checkArgPlaceholdersForOverload - Check a set of call operands for +/// placeholders. +static bool checkArgPlaceholdersForOverload(Sema &S, + MultiExprArg Args, + UnbridgedCastsSet &unbridged) { + for (unsigned i = 0, e = Args.size(); i != e; ++i) + if (checkPlaceholderForOverload(S, Args[i], &unbridged)) + return true; + + return false; +} + +/// Determine whether the given New declaration is an overload of the +/// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if +/// New and Old cannot be overloaded, e.g., if New has the same signature as +/// some function in Old (C++ 1.3.10) or if the Old declarations aren't +/// functions (or function templates) at all. When it does return Ovl_Match or +/// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be +/// overloaded with. This decl may be a UsingShadowDecl on top of the underlying +/// declaration. +/// +/// 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 contains only the 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 Ovl_Overload; MatchedDecl is +/// unchanged. +/// +/// When we process #3, Old is an overload set 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 Ovl_Match and +/// MatchedDecl will be set to point to the FunctionDecl for #2. +/// +/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class +/// by a using declaration. The rules for whether to hide shadow declarations +/// ignore some properties which otherwise figure into a function template's +/// signature. +Sema::OverloadKind +Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old, + NamedDecl *&Match, bool NewIsUsingDecl) { + for (LookupResult::iterator I = Old.begin(), E = Old.end(); + I != E; ++I) { + NamedDecl *OldD = *I; + + bool OldIsUsingDecl = false; + if (isa<UsingShadowDecl>(OldD)) { + OldIsUsingDecl = true; + + // We can always introduce two using declarations into the same + // context, even if they have identical signatures. + if (NewIsUsingDecl) continue; + + OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl(); + } + + // A using-declaration does not conflict with another declaration + // if one of them is hidden. + if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I)) + continue; + + // If either declaration was introduced by a using declaration, + // we'll need to use slightly different rules for matching. + // Essentially, these rules are the normal rules, except that + // function templates hide function templates with different + // return types or template parameter lists. + bool UseMemberUsingDeclRules = + (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() && + !New->getFriendObjectKind(); + + if (FunctionDecl *OldF = OldD->getAsFunction()) { + if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) { + if (UseMemberUsingDeclRules && OldIsUsingDecl) { + HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I)); + continue; + } + + if (!isa<FunctionTemplateDecl>(OldD) && + !shouldLinkPossiblyHiddenDecl(*I, New)) + continue; + + Match = *I; + return Ovl_Match; + } + + // Builtins that have custom typechecking or have a reference should + // not be overloadable or redeclarable. + if (!getASTContext().canBuiltinBeRedeclared(OldF)) { + Match = *I; + return Ovl_NonFunction; + } + } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) { + // We can overload with these, which can show up when doing + // redeclaration checks for UsingDecls. + assert(Old.getLookupKind() == LookupUsingDeclName); + } else if (isa<TagDecl>(OldD)) { + // We can always overload with tags by hiding them. + } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) { + // Optimistically assume that an unresolved using decl will + // overload; if it doesn't, we'll have to diagnose during + // template instantiation. + // + // Exception: if the scope is dependent and this is not a class + // member, the using declaration can only introduce an enumerator. + if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) { + Match = *I; + return Ovl_NonFunction; + } + } else { + // (C++ 13p1): + // Only function declarations can be overloaded; object and type + // declarations cannot be overloaded. + Match = *I; + return Ovl_NonFunction; + } + } + + // C++ [temp.friend]p1: + // For a friend function declaration that is not a template declaration: + // -- if the name of the friend is a qualified or unqualified template-id, + // [...], otherwise + // -- if the name of the friend is a qualified-id and a matching + // non-template function is found in the specified class or namespace, + // the friend declaration refers to that function, otherwise, + // -- if the name of the friend is a qualified-id and a matching function + // template is found in the specified class or namespace, the friend + // declaration refers to the deduced specialization of that function + // template, otherwise + // -- the name shall be an unqualified-id [...] + // If we get here for a qualified friend declaration, we've just reached the + // third bullet. If the type of the friend is dependent, skip this lookup + // until instantiation. + if (New->getFriendObjectKind() && New->getQualifier() && + !New->getDependentSpecializationInfo() && + !New->getType()->isDependentType()) { + LookupResult TemplateSpecResult(LookupResult::Temporary, Old); + TemplateSpecResult.addAllDecls(Old); + if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult, + /*QualifiedFriend*/true)) { + New->setInvalidDecl(); + return Ovl_Overload; + } + + Match = TemplateSpecResult.getAsSingle<FunctionDecl>(); + return Ovl_Match; + } + + return Ovl_Overload; +} + +bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old, + bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs) { + // C++ [basic.start.main]p2: This function shall not be overloaded. + if (New->isMain()) + return false; + + // MSVCRT user defined entry points cannot be overloaded. + if (New->isMSVCRTEntryPoint()) + return false; + + 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 == nullptr) != (NewTemplate == nullptr)) + 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; + + const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType); + const 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->getNumParams() != NewType->getNumParams() || + OldType->isVariadic() != NewType->isVariadic() || + !FunctionParamTypesAreEqual(OldType, NewType))) + 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. + // + // However, we don't consider either of these when deciding whether + // a member introduced by a shadow declaration is hidden. + if (!UseMemberUsingDeclRules && NewTemplate && + (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), + OldTemplate->getTemplateParameters(), + false, TPL_TemplateMatch) || + !Context.hasSameType(Old->getDeclaredReturnType(), + New->getDeclaredReturnType()))) + return true; + + // If the function is a class member, its signature includes the + // cv-qualifiers (if any) and ref-qualifier (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()) { + if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) { + if (!UseMemberUsingDeclRules && + (OldMethod->getRefQualifier() == RQ_None || + NewMethod->getRefQualifier() == RQ_None)) { + // C++0x [over.load]p2: + // - Member function declarations with the same name and the same + // parameter-type-list as well as member function template + // declarations with the same name, the same parameter-type-list, and + // the same template parameter lists cannot be overloaded if any of + // them, but not all, have a ref-qualifier (8.3.5). + Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload) + << NewMethod->getRefQualifier() << OldMethod->getRefQualifier(); + Diag(OldMethod->getLocation(), diag::note_previous_declaration); + } + return true; + } + + // We may not have applied the implicit const for a constexpr member + // function yet (because we haven't yet resolved whether this is a static + // or non-static member function). Add it now, on the assumption that this + // is a redeclaration of OldMethod. + // FIXME: OpenCL: Need to consider address spaces + unsigned OldQuals = OldMethod->getTypeQualifiers().getCVRUQualifiers(); + unsigned NewQuals = NewMethod->getTypeQualifiers().getCVRUQualifiers(); + if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() && + !isa<CXXConstructorDecl>(NewMethod)) + NewQuals |= Qualifiers::Const; + + // We do not allow overloading based off of '__restrict'. + OldQuals &= ~Qualifiers::Restrict; + NewQuals &= ~Qualifiers::Restrict; + if (OldQuals != NewQuals) + return true; + } + + // Though pass_object_size is placed on parameters and takes an argument, we + // consider it to be a function-level modifier for the sake of function + // identity. Either the function has one or more parameters with + // pass_object_size or it doesn't. + if (functionHasPassObjectSizeParams(New) != + functionHasPassObjectSizeParams(Old)) + return true; + + // enable_if attributes are an order-sensitive part of the signature. + for (specific_attr_iterator<EnableIfAttr> + NewI = New->specific_attr_begin<EnableIfAttr>(), + NewE = New->specific_attr_end<EnableIfAttr>(), + OldI = Old->specific_attr_begin<EnableIfAttr>(), + OldE = Old->specific_attr_end<EnableIfAttr>(); + NewI != NewE || OldI != OldE; ++NewI, ++OldI) { + if (NewI == NewE || OldI == OldE) + return true; + llvm::FoldingSetNodeID NewID, OldID; + NewI->getCond()->Profile(NewID, Context, true); + OldI->getCond()->Profile(OldID, Context, true); + if (NewID != OldID) + return true; + } + + if (getLangOpts().CUDA && ConsiderCudaAttrs) { + // Don't allow overloading of destructors. (In theory we could, but it + // would be a giant change to clang.) + if (isa<CXXDestructorDecl>(New)) + return false; + + CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New), + OldTarget = IdentifyCUDATarget(Old); + if (NewTarget == CFT_InvalidTarget) + return false; + + assert((OldTarget != CFT_InvalidTarget) && "Unexpected invalid target."); + + // Allow overloading of functions with same signature and different CUDA + // target attributes. + return NewTarget != OldTarget; + } + + // The signatures match; this is not an overload. + return false; +} + +/// Checks availability of the function depending on the current +/// function context. Inside an unavailable function, unavailability is ignored. +/// +/// \returns true if \arg FD is unavailable and current context is inside +/// an available function, false otherwise. +bool Sema::isFunctionConsideredUnavailable(FunctionDecl *FD) { + if (!FD->isUnavailable()) + return false; + + // Walk up the context of the caller. + Decl *C = cast<Decl>(CurContext); + do { + if (C->isUnavailable()) + return false; + } while ((C = cast_or_null<Decl>(C->getDeclContext()))); + return true; +} + +/// Tries a user-defined conversion from From to ToType. +/// +/// Produces an implicit conversion sequence for when a standard conversion +/// is not an option. See TryImplicitConversion for more information. +static ImplicitConversionSequence +TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType, + bool SuppressUserConversions, + bool AllowExplicit, + bool InOverloadResolution, + bool CStyle, + bool AllowObjCWritebackConversion, + bool AllowObjCConversionOnExplicit) { + ImplicitConversionSequence ICS; + + if (SuppressUserConversions) { + // We're not in the case above, so there is no conversion that + // we can perform. + ICS.setBad(BadConversionSequence::no_conversion, From, ToType); + return ICS; + } + + // Attempt user-defined conversion. + OverloadCandidateSet Conversions(From->getExprLoc(), + OverloadCandidateSet::CSK_Normal); + switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined, + Conversions, AllowExplicit, + AllowObjCConversionOnExplicit)) { + case OR_Success: + case OR_Deleted: + ICS.setUserDefined(); + // 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 + = S.Context.getCanonicalType(From->getType().getUnqualifiedType()); + QualType ToCanon + = S.Context.getCanonicalType(ToType).getUnqualifiedType(); + if (Constructor->isCopyConstructor() && + (FromCanon == ToCanon || + S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) { + // Turn this into a "standard" conversion sequence, so that it + // gets ranked with standard conversion sequences. + DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction; + ICS.setStandard(); + ICS.Standard.setAsIdentityConversion(); + ICS.Standard.setFromType(From->getType()); + ICS.Standard.setAllToTypes(ToType); + ICS.Standard.CopyConstructor = Constructor; + ICS.Standard.FoundCopyConstructor = Found; + if (ToCanon != FromCanon) + ICS.Standard.Second = ICK_Derived_To_Base; + } + } + break; + + case OR_Ambiguous: + ICS.setAmbiguous(); + ICS.Ambiguous.setFromType(From->getType()); + ICS.Ambiguous.setToType(ToType); + for (OverloadCandidateSet::iterator Cand = Conversions.begin(); + Cand != Conversions.end(); ++Cand) + if (Cand->Viable) + ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function); + break; + + // Fall through. + case OR_No_Viable_Function: + ICS.setBad(BadConversionSequence::no_conversion, From, ToType); + break; + } + + return ICS; +} + +/// 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. +/// +/// \param AllowObjCWritebackConversion Whether we allow the Objective-C +/// writeback conversion, which allows __autoreleasing id* parameters to +/// be initialized with __strong id* or __weak id* arguments. +static ImplicitConversionSequence +TryImplicitConversion(Sema &S, Expr *From, QualType ToType, + bool SuppressUserConversions, + bool AllowExplicit, + bool InOverloadResolution, + bool CStyle, + bool AllowObjCWritebackConversion, + bool AllowObjCConversionOnExplicit) { + ImplicitConversionSequence ICS; + if (IsStandardConversion(S, From, ToType, InOverloadResolution, + ICS.Standard, CStyle, AllowObjCWritebackConversion)){ + ICS.setStandard(); + return ICS; + } + + if (!S.getLangOpts().CPlusPlus) { + ICS.setBad(BadConversionSequence::no_conversion, From, ToType); + return ICS; + } + + // 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/move + // constructor (i.e., a user-defined conversion function) is + // called for those cases. + QualType FromType = From->getType(); + if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() && + (S.Context.hasSameUnqualifiedType(FromType, ToType) || + S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) { + ICS.setStandard(); + ICS.Standard.setAsIdentityConversion(); + ICS.Standard.setFromType(FromType); + ICS.Standard.setAllToTypes(ToType); + + // We don't actually check at this point whether there is a valid + // copy/move constructor, since overloading just assumes that it + // exists. When we actually perform initialization, we'll find the + // appropriate constructor to copy the returned object, if needed. + ICS.Standard.CopyConstructor = nullptr; + + // Determine whether this is considered a derived-to-base conversion. + if (!S.Context.hasSameUnqualifiedType(FromType, ToType)) + ICS.Standard.Second = ICK_Derived_To_Base; + + return ICS; + } + + return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions, + AllowExplicit, InOverloadResolution, CStyle, + AllowObjCWritebackConversion, + AllowObjCConversionOnExplicit); +} + +ImplicitConversionSequence +Sema::TryImplicitConversion(Expr *From, QualType ToType, + bool SuppressUserConversions, + bool AllowExplicit, + bool InOverloadResolution, + bool CStyle, + bool AllowObjCWritebackConversion) { + return ::TryImplicitConversion(*this, From, ToType, + SuppressUserConversions, AllowExplicit, + InOverloadResolution, CStyle, + AllowObjCWritebackConversion, + /*AllowObjCConversionOnExplicit=*/false); +} + +/// PerformImplicitConversion - Perform an implicit conversion of the +/// expression From to the type ToType. Returns the +/// converted expression. Flavor is the kind of conversion we're +/// performing, used in the error message. If @p AllowExplicit, +/// explicit user-defined conversions are permitted. +ExprResult +Sema::PerformImplicitConversion(Expr *From, QualType ToType, + AssignmentAction Action, bool AllowExplicit) { + ImplicitConversionSequence ICS; + return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS); +} + +ExprResult +Sema::PerformImplicitConversion(Expr *From, QualType ToType, + AssignmentAction Action, bool AllowExplicit, + ImplicitConversionSequence& ICS) { + if (checkPlaceholderForOverload(*this, From)) + return ExprError(); + + // Objective-C ARC: Determine whether we will allow the writeback conversion. + bool AllowObjCWritebackConversion + = getLangOpts().ObjCAutoRefCount && + (Action == AA_Passing || Action == AA_Sending); + if (getLangOpts().ObjC) + CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType, + From->getType(), From); + ICS = ::TryImplicitConversion(*this, From, ToType, + /*SuppressUserConversions=*/false, + AllowExplicit, + /*InOverloadResolution=*/false, + /*CStyle=*/false, + AllowObjCWritebackConversion, + /*AllowObjCConversionOnExplicit=*/false); + return PerformImplicitConversion(From, ToType, ICS, Action); +} + +/// Determine whether the conversion from FromType to ToType is a valid +/// conversion that strips "noexcept" or "noreturn" off the nested function +/// type. +bool Sema::IsFunctionConversion(QualType FromType, QualType ToType, + QualType &ResultTy) { + if (Context.hasSameUnqualifiedType(FromType, ToType)) + return false; + + // Permit the conversion F(t __attribute__((noreturn))) -> F(t) + // or F(t noexcept) -> F(t) + // where F adds one of the following at most once: + // - a pointer + // - a member pointer + // - a block pointer + // Changes here need matching changes in FindCompositePointerType. + CanQualType CanTo = Context.getCanonicalType(ToType); + CanQualType CanFrom = Context.getCanonicalType(FromType); + Type::TypeClass TyClass = CanTo->getTypeClass(); + if (TyClass != CanFrom->getTypeClass()) return false; + if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) { + if (TyClass == Type::Pointer) { + CanTo = CanTo.getAs<PointerType>()->getPointeeType(); + CanFrom = CanFrom.getAs<PointerType>()->getPointeeType(); + } else if (TyClass == Type::BlockPointer) { + CanTo = CanTo.getAs<BlockPointerType>()->getPointeeType(); + CanFrom = CanFrom.getAs<BlockPointerType>()->getPointeeType(); + } else if (TyClass == Type::MemberPointer) { + auto ToMPT = CanTo.getAs<MemberPointerType>(); + auto FromMPT = CanFrom.getAs<MemberPointerType>(); + // A function pointer conversion cannot change the class of the function. + if (ToMPT->getClass() != FromMPT->getClass()) + return false; + CanTo = ToMPT->getPointeeType(); + CanFrom = FromMPT->getPointeeType(); + } else { + return false; + } + + TyClass = CanTo->getTypeClass(); + if (TyClass != CanFrom->getTypeClass()) return false; + if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) + return false; + } + + const auto *FromFn = cast<FunctionType>(CanFrom); + FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo(); + + const auto *ToFn = cast<FunctionType>(CanTo); + FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo(); + + bool Changed = false; + + // Drop 'noreturn' if not present in target type. + if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) { + FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false)); + Changed = true; + } + + // Drop 'noexcept' if not present in target type. + if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) { + const auto *ToFPT = cast<FunctionProtoType>(ToFn); + if (FromFPT->isNothrow() && !ToFPT->isNothrow()) { + FromFn = cast<FunctionType>( + Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0), + EST_None) + .getTypePtr()); + Changed = true; + } + + // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid + // only if the ExtParameterInfo lists of the two function prototypes can be + // merged and the merged list is identical to ToFPT's ExtParameterInfo list. + SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos; + bool CanUseToFPT, CanUseFromFPT; + if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT, + CanUseFromFPT, NewParamInfos) && + CanUseToFPT && !CanUseFromFPT) { + FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo(); + ExtInfo.ExtParameterInfos = + NewParamInfos.empty() ? nullptr : NewParamInfos.data(); + QualType QT = Context.getFunctionType(FromFPT->getReturnType(), + FromFPT->getParamTypes(), ExtInfo); + FromFn = QT->getAs<FunctionType>(); + Changed = true; + } + } + + if (!Changed) + return false; + + assert(QualType(FromFn, 0).isCanonical()); + if (QualType(FromFn, 0) != CanTo) return false; + + ResultTy = ToType; + return true; +} + +/// Determine whether the conversion from FromType to ToType is a valid +/// vector conversion. +/// +/// \param ICK Will be set to the vector conversion kind, if this is a vector +/// conversion. +static bool IsVectorConversion(Sema &S, QualType FromType, + QualType ToType, ImplicitConversionKind &ICK) { + // We need at least one of these types to be a vector type to have a vector + // conversion. + if (!ToType->isVectorType() && !FromType->isVectorType()) + return false; + + // Identical types require no conversions. + if (S.Context.hasSameUnqualifiedType(FromType, ToType)) + return false; + + // There are no conversions between extended vector types, only identity. + if (ToType->isExtVectorType()) { + // There are no conversions between extended vector types other than the + // identity conversion. + if (FromType->isExtVectorType()) + return false; + + // Vector splat from any arithmetic type to a vector. + if (FromType->isArithmeticType()) { + ICK = ICK_Vector_Splat; + return true; + } + } + + // We can perform the conversion between vector types in the following cases: + // 1)vector types are equivalent AltiVec and GCC vector types + // 2)lax vector conversions are permitted and the vector types are of the + // same size + if (ToType->isVectorType() && FromType->isVectorType()) { + if (S.Context.areCompatibleVectorTypes(FromType, ToType) || + S.isLaxVectorConversion(FromType, ToType)) { + ICK = ICK_Vector_Conversion; + return true; + } + } + + return false; +} + +static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle); + +/// 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. +static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle, + bool AllowObjCWritebackConversion) { + QualType FromType = From->getType(); + + // Standard conversions (C++ [conv]) + SCS.setAsIdentityConversion(); + SCS.IncompatibleObjC = false; + SCS.setFromType(FromType); + SCS.CopyConstructor = nullptr; + + // There are no standard conversions for class types in C++, so + // abort early. When overloading in C, however, we do permit them. + if (S.getLangOpts().CPlusPlus && + (FromType->isRecordType() || ToType->isRecordType())) + return false; + + // The first conversion can be an lvalue-to-rvalue conversion, + // array-to-pointer conversion, or function-to-pointer conversion + // (C++ 4p1). + + if (FromType == S.Context.OverloadTy) { + DeclAccessPair AccessPair; + if (FunctionDecl *Fn + = S.ResolveAddressOfOverloadedFunction(From, ToType, false, + AccessPair)) { + // We were able to resolve the address of the overloaded function, + // so we can convert to the type of that function. + FromType = Fn->getType(); + SCS.setFromType(FromType); + + // we can sometimes resolve &foo<int> regardless of ToType, so check + // if the type matches (identity) or we are converting to bool + if (!S.Context.hasSameUnqualifiedType( + S.ExtractUnqualifiedFunctionType(ToType), FromType)) { + QualType resultTy; + // if the function type matches except for [[noreturn]], it's ok + if (!S.IsFunctionConversion(FromType, + S.ExtractUnqualifiedFunctionType(ToType), resultTy)) + // otherwise, only a boolean conversion is standard + if (!ToType->isBooleanType()) + return false; + } + + // Check if the "from" expression is taking the address of an overloaded + // function and recompute the FromType accordingly. Take advantage of the + // fact that non-static member functions *must* have such an address-of + // expression. + CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn); + if (Method && !Method->isStatic()) { + assert(isa<UnaryOperator>(From->IgnoreParens()) && + "Non-unary operator on non-static member address"); + assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() + == UO_AddrOf && + "Non-address-of operator on non-static member address"); + const Type *ClassType + = S.Context.getTypeDeclType(Method->getParent()).getTypePtr(); + FromType = S.Context.getMemberPointerType(FromType, ClassType); + } else if (isa<UnaryOperator>(From->IgnoreParens())) { + assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() == + UO_AddrOf && + "Non-address-of operator for overloaded function expression"); + FromType = S.Context.getPointerType(FromType); + } + + // Check that we've computed the proper type after overload resolution. + // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't + // be calling it from within an NDEBUG block. + assert(S.Context.hasSameType( + FromType, + S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())); + } else { + return false; + } + } + // Lvalue-to-rvalue conversion (C++11 4.1): + // A glvalue (3.10) of a non-function, non-array type T can + // be converted to a prvalue. + bool argIsLValue = From->isGLValue(); + if (argIsLValue && + !FromType->isFunctionType() && !FromType->isArrayType() && + S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) { + SCS.First = ICK_Lvalue_To_Rvalue; + + // C11 6.3.2.1p2: + // ... if the lvalue has atomic type, the value has the non-atomic version + // of the type of the lvalue ... + if (const AtomicType *Atomic = FromType->getAs<AtomicType>()) + FromType = Atomic->getValueType(); + + // 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. + 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 = S.Context.getArrayDecayedType(FromType); + + if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) { + // This conversion is deprecated in C++03 (D.4) + SCS.DeprecatedStringLiteralToCharPtr = 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.QualificationIncludesObjCLifetime = false; + SCS.setAllToTypes(FromType); + return true; + } + } else if (FromType->isFunctionType() && argIsLValue) { + // Function-to-pointer conversion (C++ 4.3). + SCS.First = ICK_Function_To_Pointer; + + if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts())) + if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) + if (!S.checkAddressOfFunctionIsAvailable(FD)) + return false; + + // 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 = S.Context.getPointerType(FromType); + } else { + // We don't require any conversions for the first step. + SCS.First = ICK_Identity; + } + SCS.setToType(0, FromType); + + // 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; + ImplicitConversionKind SecondICK = ICK_Identity; + if (S.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 (S.IsIntegralPromotion(From, FromType, ToType)) { + // Integral promotion (C++ 4.5). + SCS.Second = ICK_Integral_Promotion; + FromType = ToType.getUnqualifiedType(); + } else if (S.IsFloatingPointPromotion(FromType, ToType)) { + // Floating point promotion (C++ 4.6). + SCS.Second = ICK_Floating_Promotion; + FromType = ToType.getUnqualifiedType(); + } else if (S.IsComplexPromotion(FromType, ToType)) { + // Complex promotion (Clang extension) + SCS.Second = ICK_Complex_Promotion; + FromType = ToType.getUnqualifiedType(); + } else if (ToType->isBooleanType() && + (FromType->isArithmeticType() || + FromType->isAnyPointerType() || + FromType->isBlockPointerType() || + FromType->isMemberPointerType() || + FromType->isNullPtrType())) { + // Boolean conversions (C++ 4.12). + SCS.Second = ICK_Boolean_Conversion; + FromType = S.Context.BoolTy; + } else if (FromType->isIntegralOrUnscopedEnumerationType() && + ToType->isIntegralType(S.Context)) { + // Integral conversions (C++ 4.7). + SCS.Second = ICK_Integral_Conversion; + FromType = ToType.getUnqualifiedType(); + } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) { + // Complex conversions (C99 6.3.1.6) + SCS.Second = ICK_Complex_Conversion; + FromType = ToType.getUnqualifiedType(); + } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) || + (ToType->isAnyComplexType() && FromType->isArithmeticType())) { + // Complex-real conversions (C99 6.3.1.7) + SCS.Second = ICK_Complex_Real; + FromType = ToType.getUnqualifiedType(); + } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) { + // FIXME: disable conversions between long double and __float128 if + // their representation is different until there is back end support + // We of course allow this conversion if long double is really double. + if (&S.Context.getFloatTypeSemantics(FromType) != + &S.Context.getFloatTypeSemantics(ToType)) { + bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty && + ToType == S.Context.LongDoubleTy) || + (FromType == S.Context.LongDoubleTy && + ToType == S.Context.Float128Ty)); + if (Float128AndLongDouble && + (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) == + &llvm::APFloat::PPCDoubleDouble())) + return false; + } + // Floating point conversions (C++ 4.8). + SCS.Second = ICK_Floating_Conversion; + FromType = ToType.getUnqualifiedType(); + } else if ((FromType->isRealFloatingType() && + ToType->isIntegralType(S.Context)) || + (FromType->isIntegralOrUnscopedEnumerationType() && + ToType->isRealFloatingType())) { + // Floating-integral conversions (C++ 4.9). + SCS.Second = ICK_Floating_Integral; + FromType = ToType.getUnqualifiedType(); + } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) { + SCS.Second = ICK_Block_Pointer_Conversion; + } else if (AllowObjCWritebackConversion && + S.isObjCWritebackConversion(FromType, ToType, FromType)) { + SCS.Second = ICK_Writeback_Conversion; + } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution, + FromType, IncompatibleObjC)) { + // Pointer conversions (C++ 4.10). + SCS.Second = ICK_Pointer_Conversion; + SCS.IncompatibleObjC = IncompatibleObjC; + FromType = FromType.getUnqualifiedType(); + } else if (S.IsMemberPointerConversion(From, FromType, ToType, + InOverloadResolution, FromType)) { + // Pointer to member conversions (4.11). + SCS.Second = ICK_Pointer_Member; + } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) { + SCS.Second = SecondICK; + FromType = ToType.getUnqualifiedType(); + } else if (!S.getLangOpts().CPlusPlus && + S.Context.typesAreCompatible(ToType, FromType)) { + // Compatible conversions (Clang extension for C function overloading) + SCS.Second = ICK_Compatible_Conversion; + FromType = ToType.getUnqualifiedType(); + } else if (IsTransparentUnionStandardConversion(S, From, ToType, + InOverloadResolution, + SCS, CStyle)) { + SCS.Second = ICK_TransparentUnionConversion; + FromType = ToType; + } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS, + CStyle)) { + // tryAtomicConversion has updated the standard conversion sequence + // appropriately. + return true; + } else if (ToType->isEventT() && + From->isIntegerConstantExpr(S.getASTContext()) && + From->EvaluateKnownConstInt(S.getASTContext()) == 0) { + SCS.Second = ICK_Zero_Event_Conversion; + FromType = ToType; + } else if (ToType->isQueueT() && + From->isIntegerConstantExpr(S.getASTContext()) && + (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) { + SCS.Second = ICK_Zero_Queue_Conversion; + FromType = ToType; + } else { + // No second conversion required. + SCS.Second = ICK_Identity; + } + SCS.setToType(1, FromType); + + // The third conversion can be a function pointer conversion or a + // qualification conversion (C++ [conv.fctptr], [conv.qual]). + bool ObjCLifetimeConversion; + if (S.IsFunctionConversion(FromType, ToType, FromType)) { + // Function pointer conversions (removing 'noexcept') including removal of + // 'noreturn' (Clang extension). + SCS.Third = ICK_Function_Conversion; + } else if (S.IsQualificationConversion(FromType, ToType, CStyle, + ObjCLifetimeConversion)) { + SCS.Third = ICK_Qualification; + SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion; + FromType = 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. [...] + QualType CanonFrom = S.Context.getCanonicalType(FromType); + QualType CanonTo = S.Context.getCanonicalType(ToType); + if (CanonFrom.getLocalUnqualifiedType() + == CanonTo.getLocalUnqualifiedType() && + CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) { + FromType = ToType; + CanonFrom = CanonTo; + } + + SCS.setToType(2, FromType); + + if (CanonFrom == CanonTo) + return true; + + // If we have not converted the argument type to the parameter type, + // this is a bad conversion sequence, unless we're resolving an overload in C. + if (S.getLangOpts().CPlusPlus || !InOverloadResolution) + return false; + + ExprResult ER = ExprResult{From}; + Sema::AssignConvertType Conv = + S.CheckSingleAssignmentConstraints(ToType, ER, + /*Diagnose=*/false, + /*DiagnoseCFAudited=*/false, + /*ConvertRHS=*/false); + ImplicitConversionKind SecondConv; + switch (Conv) { + case Sema::Compatible: + SecondConv = ICK_C_Only_Conversion; + break; + // For our purposes, discarding qualifiers is just as bad as using an + // incompatible pointer. Note that an IncompatiblePointer conversion can drop + // qualifiers, as well. + case Sema::CompatiblePointerDiscardsQualifiers: + case Sema::IncompatiblePointer: + case Sema::IncompatiblePointerSign: + SecondConv = ICK_Incompatible_Pointer_Conversion; + break; + default: + return false; + } + + // First can only be an lvalue conversion, so we pretend that this was the + // second conversion. First should already be valid from earlier in the + // function. + SCS.Second = SecondConv; + SCS.setToType(1, ToType); + + // Third is Identity, because Second should rank us worse than any other + // conversion. This could also be ICK_Qualification, but it's simpler to just + // lump everything in with the second conversion, and we don't gain anything + // from making this ICK_Qualification. + SCS.Third = ICK_Identity; + SCS.setToType(2, ToType); + return true; +} + +static bool +IsTransparentUnionStandardConversion(Sema &S, Expr* From, + QualType &ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle) { + + const RecordType *UT = ToType->getAsUnionType(); + if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>()) + return false; + // The field to initialize within the transparent union. + RecordDecl *UD = UT->getDecl(); + // It's compatible if the expression matches any of the fields. + for (const auto *it : UD->fields()) { + if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS, + CStyle, /*ObjCWritebackConversion=*/false)) { + ToType = it->getType(); + return true; + } + } + return false; +} + +/// 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->getAs<BuiltinType>(); + // 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() && + !FromType->isEnumeralType()) { + 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. + Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) { + return To->getKind() == BuiltinType::Int; + } + + return To->getKind() == BuiltinType::UInt; + } + + // C++11 [conv.prom]p3: + // A prvalue of an unscoped enumeration type whose underlying type is not + // fixed (7.2) can be converted to an rvalue a prvalue of the first of the + // following types that can represent all the values of the enumeration + // (i.e., the values in the range bmin to bmax as described in 7.2): int, + // unsigned int, long int, unsigned long int, long long int, or unsigned + // long long int. If none of the types in that list can represent all the + // values of the enumeration, an rvalue a prvalue of an unscoped enumeration + // type can be converted to an rvalue a prvalue of the extended integer type + // with lowest integer conversion rank (4.13) greater than the rank of long + // long in which all the values of the enumeration can be represented. If + // there are two such extended types, the signed one is chosen. + // C++11 [conv.prom]p4: + // A prvalue of an unscoped enumeration type whose underlying type is fixed + // can be converted to a prvalue of its underlying type. Moreover, if + // integral promotion can be applied to its underlying type, a prvalue of an + // unscoped enumeration type whose underlying type is fixed can also be + // converted to a prvalue of the promoted underlying type. + if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) { + // C++0x 7.2p9: Note that this implicit enum to int conversion is not + // provided for a scoped enumeration. + if (FromEnumType->getDecl()->isScoped()) + return false; + + // We can perform an integral promotion to the underlying type of the enum, + // even if that's not the promoted type. Note that the check for promoting + // the underlying type is based on the type alone, and does not consider + // the bitfield-ness of the actual source expression. + if (FromEnumType->getDecl()->isFixed()) { + QualType Underlying = FromEnumType->getDecl()->getIntegerType(); + return Context.hasSameUnqualifiedType(Underlying, ToType) || + IsIntegralPromotion(nullptr, Underlying, ToType); + } + + // We have already pre-calculated the promotion type, so this is trivial. + if (ToType->isIntegerType() && + isCompleteType(From->getBeginLoc(), FromType)) + return Context.hasSameUnqualifiedType( + ToType, FromEnumType->getDecl()->getPromotionType()); + + // C++ [conv.prom]p5: + // If the bit-field has an enumerated type, it is treated as any other + // value of that type for promotion purposes. + // + // ... so do not fall through into the bit-field checks below in C++. + if (getLangOpts().CPlusPlus) + return false; + } + + // C++0x [conv.prom]p2: + // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted + // to an rvalue a prvalue of the first of the following types that can + // represent all the values of its underlying type: int, unsigned int, + // long int, unsigned long int, long long int, or unsigned long long int. + // If none of the types in that list can represent all the values of its + // underlying type, an rvalue a prvalue of type char16_t, char32_t, + // or wchar_t can be converted to an rvalue a prvalue of its underlying + // type. + if (FromType->isAnyCharacterType() && !FromType->isCharType() && + ToType->isIntegerType()) { + // Determine whether the type we're converting from is signed or + // unsigned. + bool FromIsSigned = FromType->isSignedIntegerType(); + uint64_t FromSize = Context.getTypeSize(FromType); + + // 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.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); + } + } + } + + // 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. + // + // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be + // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum + // bit-fields and those whose underlying type is larger than int) for GCC + // compatibility. + if (From) { + if (FieldDecl *MemberDecl = From->getSourceBitField()) { + llvm::APSInt BitWidth; + if (FromType->isIntegralType(Context) && + MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { + llvm::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) { + if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) + if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { + /// An rvalue of type float can be converted to an rvalue of type + /// double. (C++ 4.6p1). + 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 (!getLangOpts().CPlusPlus && + (FromBuiltin->getKind() == BuiltinType::Float || + FromBuiltin->getKind() == BuiltinType::Double) && + (ToBuiltin->getKind() == BuiltinType::LongDouble || + ToBuiltin->getKind() == BuiltinType::Float128)) + return true; + + // Half can be promoted to float. + if (!getLangOpts().NativeHalfType && + FromBuiltin->getKind() == BuiltinType::Half && + ToBuiltin->getKind() == BuiltinType::Float) + return true; + } + + return false; +} + +/// 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->getAs<ComplexType>(); + if (!FromComplex) + return false; + + const ComplexType *ToComplex = ToType->getAs<ComplexType>(); + if (!ToComplex) + return false; + + return IsFloatingPointPromotion(FromComplex->getElementType(), + ToComplex->getElementType()) || + IsIntegralPromotion(nullptr, 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 Type *FromPtr, + QualType ToPointee, QualType ToType, + ASTContext &Context, + bool StripObjCLifetime = false) { + assert((FromPtr->getTypeClass() == Type::Pointer || + FromPtr->getTypeClass() == Type::ObjCObjectPointer) && + "Invalid similarly-qualified pointer type"); + + /// Conversions to 'id' subsume cv-qualifier conversions. + if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType()) + return ToType.getUnqualifiedType(); + + QualType CanonFromPointee + = Context.getCanonicalType(FromPtr->getPointeeType()); + QualType CanonToPointee = Context.getCanonicalType(ToPointee); + Qualifiers Quals = CanonFromPointee.getQualifiers(); + + if (StripObjCLifetime) + Quals.removeObjCLifetime(); + + // Exact qualifier match -> return the pointer type we're converting to. + if (CanonToPointee.getLocalQualifiers() == Quals) { + // ToType is exactly what we need. Return it. + if (!ToType.isNull()) + return ToType.getUnqualifiedType(); + + // Build a pointer to ToPointee. It has the right qualifiers + // already. + if (isa<ObjCObjectPointerType>(ToType)) + return Context.getObjCObjectPointerType(ToPointee); + return Context.getPointerType(ToPointee); + } + + // Just build a canonical type that has the right qualifiers. + QualType QualifiedCanonToPointee + = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals); + + if (isa<ObjCObjectPointerType>(ToType)) + return Context.getObjCObjectPointerType(QualifiedCanonToPointee); + return Context.getPointerType(QualifiedCanonToPointee); +} + +static bool isNullPointerConstantForConversion(Expr *Expr, + bool InOverloadResolution, + ASTContext &Context) { + // Handle value-dependent integral null pointer constants correctly. + // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 + if (Expr->isValueDependent() && !Expr->isTypeDependent() && + Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType()) + return !InOverloadResolution; + + return Expr->isNullPointerConstant(Context, + InOverloadResolution? Expr::NPC_ValueDependentIsNotNull + : Expr::NPC_ValueDependentIsNull); +} + +/// 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, + bool InOverloadResolution, + 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() && + isNullPointerConstantForConversion(From, InOverloadResolution, 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() && + isNullPointerConstantForConversion(From, InOverloadResolution, 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() && + isNullPointerConstantForConversion(From, InOverloadResolution, 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 (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { + ConvertedType = ToType; + return true; + } + + // Beyond this point, both types need to be pointers + // , including objective-c pointers. + QualType ToPointeeType = ToTypePtr->getPointeeType(); + if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() && + !getLangOpts().ObjCAutoRefCount) { + ConvertedType = BuildSimilarlyQualifiedPointerType( + FromType->getAs<ObjCObjectPointerType>(), + ToPointeeType, + ToType, Context); + return true; + } + const PointerType *FromTypePtr = FromType->getAs<PointerType>(); + if (!FromTypePtr) + return false; + + QualType FromPointeeType = FromTypePtr->getPointeeType(); + + // If the unqualified pointee types are the same, this can't be a + // pointer conversion, so don't do all of the work below. + if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) + return false; + + // 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->isIncompleteOrObjectType() && + ToPointeeType->isVoidType()) { + ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, + ToPointeeType, + ToType, Context, + /*StripObjCLifetime=*/true); + return true; + } + + // MSVC allows implicit function to void* type conversion. + if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() && + 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 (!getLangOpts().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 (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() && + ToPointeeType->isRecordType() && + !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && + IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) { + ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, + ToPointeeType, + ToType, Context); + return true; + } + + if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() && + Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) { + ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, + ToPointeeType, + ToType, Context); + return true; + } + + return false; +} + +/// Adopt the given qualifiers for the given type. +static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){ + Qualifiers TQs = T.getQualifiers(); + + // Check whether qualifiers already match. + if (TQs == Qs) + return T; + + if (Qs.compatiblyIncludes(TQs)) + return Context.getQualifiedType(T, Qs); + + return Context.getQualifiedType(T.getUnqualifiedType(), Qs); +} + +/// 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 (!getLangOpts().ObjC) + return false; + + // The set of qualifiers on the type we're converting from. + Qualifiers FromQualifiers = FromType.getQualifiers(); + + // First, we handle all conversions on ObjC object pointer types. + const ObjCObjectPointerType* ToObjCPtr = + ToType->getAs<ObjCObjectPointerType>(); + const ObjCObjectPointerType *FromObjCPtr = + FromType->getAs<ObjCObjectPointerType>(); + + if (ToObjCPtr && FromObjCPtr) { + // If the pointee types are the same (ignoring qualifications), + // then this is not a pointer conversion. + if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(), + FromObjCPtr->getPointeeType())) + return false; + + // Conversion between Objective-C pointers. + if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { + const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); + const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); + if (getLangOpts().CPlusPlus && LHS && RHS && + !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( + FromObjCPtr->getPointeeType())) + return false; + ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr, + ToObjCPtr->getPointeeType(), + ToType, Context); + ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); + 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 = BuildSimilarlyQualifiedPointerType(FromObjCPtr, + ToObjCPtr->getPointeeType(), + ToType, Context); + ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); + 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>()) { + // Objective C++: We're able to convert from a pointer to any object + // to a block pointer type. + if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { + ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers); + return true; + } + ToPointeeType = ToBlockPtr->getPointeeType(); + } + else if (FromType->getAs<BlockPointerType>() && + ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { + // Objective C++: We're able to convert from a block pointer type to a + // pointer to any object. + ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers); + return true; + } + 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 = Context.getPointerType(ConvertedType); + ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); + return true; + } + // Allow conversion of pointee being objective-c pointer to another one; + // as in I* to id. + if (FromPointeeType->getAs<ObjCObjectPointerType>() && + ToPointeeType->getAs<ObjCObjectPointerType>() && + isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, + IncompatibleObjC)) { + + ConvertedType = Context.getPointerType(ConvertedType); + ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers); + 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->getAs<FunctionProtoType>(); + const FunctionProtoType *ToFunctionType + = ToPointeeType->getAs<FunctionProtoType>(); + 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->getNumParams() != ToFunctionType->getNumParams() || + FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || + FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) + return false; + + bool HasObjCConversion = false; + if (Context.getCanonicalType(FromFunctionType->getReturnType()) == + Context.getCanonicalType(ToFunctionType->getReturnType())) { + // Okay, the types match exactly. Nothing to do. + } else if (isObjCPointerConversion(FromFunctionType->getReturnType(), + ToFunctionType->getReturnType(), + 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->getNumParams(); + ArgIdx != NumArgs; ++ArgIdx) { + QualType FromArgType = FromFunctionType->getParamType(ArgIdx); + QualType ToArgType = ToFunctionType->getParamType(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 = AdoptQualifiers(Context, ToType, FromQualifiers); + IncompatibleObjC = true; + return true; + } + } + + return false; +} + +/// Determine whether this is an Objective-C writeback conversion, +/// used for parameter passing when performing automatic reference counting. +/// +/// \param FromType The type we're converting form. +/// +/// \param ToType The type we're converting to. +/// +/// \param ConvertedType The type that will be produced after applying +/// this conversion. +bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType, + QualType &ConvertedType) { + if (!getLangOpts().ObjCAutoRefCount || + Context.hasSameUnqualifiedType(FromType, ToType)) + return false; + + // Parameter must be a pointer to __autoreleasing (with no other qualifiers). + QualType ToPointee; + if (const PointerType *ToPointer = ToType->getAs<PointerType>()) + ToPointee = ToPointer->getPointeeType(); + else + return false; + + Qualifiers ToQuals = ToPointee.getQualifiers(); + if (!ToPointee->isObjCLifetimeType() || + ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing || + !ToQuals.withoutObjCLifetime().empty()) + return false; + + // Argument must be a pointer to __strong to __weak. + QualType FromPointee; + if (const PointerType *FromPointer = FromType->getAs<PointerType>()) + FromPointee = FromPointer->getPointeeType(); + else + return false; + + Qualifiers FromQuals = FromPointee.getQualifiers(); + if (!FromPointee->isObjCLifetimeType() || + (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong && + FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak)) + return false; + + // Make sure that we have compatible qualifiers. + FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing); + if (!ToQuals.compatiblyIncludes(FromQuals)) + return false; + + // Remove qualifiers from the pointee type we're converting from; they + // aren't used in the compatibility check belong, and we'll be adding back + // qualifiers (with __autoreleasing) if the compatibility check succeeds. + FromPointee = FromPointee.getUnqualifiedType(); + + // The unqualified form of the pointee types must be compatible. + ToPointee = ToPointee.getUnqualifiedType(); + bool IncompatibleObjC; + if (Context.typesAreCompatible(FromPointee, ToPointee)) + FromPointee = ToPointee; + else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee, + IncompatibleObjC)) + return false; + + /// Construct the type we're converting to, which is a pointer to + /// __autoreleasing pointee. + FromPointee = Context.getQualifiedType(FromPointee, FromQuals); + ConvertedType = Context.getPointerType(FromPointee); + return true; +} + +bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType, + QualType& ConvertedType) { + QualType ToPointeeType; + if (const BlockPointerType *ToBlockPtr = + ToType->getAs<BlockPointerType>()) + ToPointeeType = ToBlockPtr->getPointeeType(); + else + return false; + + QualType FromPointeeType; + if (const BlockPointerType *FromBlockPtr = + FromType->getAs<BlockPointerType>()) + FromPointeeType = FromBlockPtr->getPointeeType(); + else + return false; + // We have pointer to blocks, check whether the only + // differences in the argument and result types are in Objective-C + // pointer conversions. If so, we permit the conversion. + + const FunctionProtoType *FromFunctionType + = FromPointeeType->getAs<FunctionProtoType>(); + const FunctionProtoType *ToFunctionType + = ToPointeeType->getAs<FunctionProtoType>(); + + if (!FromFunctionType || !ToFunctionType) + return false; + + if (Context.hasSameType(FromPointeeType, ToPointeeType)) + return true; + + // Perform the quick checks that will tell us whether these + // function types are obviously different. + if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() || + FromFunctionType->isVariadic() != ToFunctionType->isVariadic()) + return false; + + FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo(); + FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo(); + if (FromEInfo != ToEInfo) + return false; + + bool IncompatibleObjC = false; + if (Context.hasSameType(FromFunctionType->getReturnType(), + ToFunctionType->getReturnType())) { + // Okay, the types match exactly. Nothing to do. + } else { + QualType RHS = FromFunctionType->getReturnType(); + QualType LHS = ToFunctionType->getReturnType(); + if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) && + !RHS.hasQualifiers() && LHS.hasQualifiers()) + LHS = LHS.getUnqualifiedType(); + + if (Context.hasSameType(RHS,LHS)) { + // OK exact match. + } else if (isObjCPointerConversion(RHS, LHS, + ConvertedType, IncompatibleObjC)) { + if (IncompatibleObjC) + return false; + // Okay, we have an Objective-C pointer conversion. + } + else + return false; + } + + // Check argument types. + for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams(); + ArgIdx != NumArgs; ++ArgIdx) { + IncompatibleObjC = false; + QualType FromArgType = FromFunctionType->getParamType(ArgIdx); + QualType ToArgType = ToFunctionType->getParamType(ArgIdx); + if (Context.hasSameType(FromArgType, ToArgType)) { + // Okay, the types match exactly. Nothing to do. + } else if (isObjCPointerConversion(ToArgType, FromArgType, + ConvertedType, IncompatibleObjC)) { + if (IncompatibleObjC) + return false; + // Okay, we have an Objective-C pointer conversion. + } else + // Argument types are too different. Abort. + return false; + } + + SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos; + bool CanUseToFPT, CanUseFromFPT; + if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType, + CanUseToFPT, CanUseFromFPT, + NewParamInfos)) + return false; + + ConvertedType = ToType; + return true; +} + +enum { + ft_default, + ft_different_class, + ft_parameter_arity, + ft_parameter_mismatch, + ft_return_type, + ft_qualifer_mismatch, + ft_noexcept +}; + +/// Attempts to get the FunctionProtoType from a Type. Handles +/// MemberFunctionPointers properly. +static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) { + if (auto *FPT = FromType->getAs<FunctionProtoType>()) + return FPT; + + if (auto *MPT = FromType->getAs<MemberPointerType>()) + return MPT->getPointeeType()->getAs<FunctionProtoType>(); + + return nullptr; +} + +/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing +/// function types. Catches different number of parameter, mismatch in +/// parameter types, and different return types. +void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag, + QualType FromType, QualType ToType) { + // If either type is not valid, include no extra info. + if (FromType.isNull() || ToType.isNull()) { + PDiag << ft_default; + return; + } + + // Get the function type from the pointers. + if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) { + const MemberPointerType *FromMember = FromType->getAs<MemberPointerType>(), + *ToMember = ToType->getAs<MemberPointerType>(); + if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) { + PDiag << ft_different_class << QualType(ToMember->getClass(), 0) + << QualType(FromMember->getClass(), 0); + return; + } + FromType = FromMember->getPointeeType(); + ToType = ToMember->getPointeeType(); + } + + if (FromType->isPointerType()) + FromType = FromType->getPointeeType(); + if (ToType->isPointerType()) + ToType = ToType->getPointeeType(); + + // Remove references. + FromType = FromType.getNonReferenceType(); + ToType = ToType.getNonReferenceType(); + + // Don't print extra info for non-specialized template functions. + if (FromType->isInstantiationDependentType() && + !FromType->getAs<TemplateSpecializationType>()) { + PDiag << ft_default; + return; + } + + // No extra info for same types. + if (Context.hasSameType(FromType, ToType)) { + PDiag << ft_default; + return; + } + + const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType), + *ToFunction = tryGetFunctionProtoType(ToType); + + // Both types need to be function types. + if (!FromFunction || !ToFunction) { + PDiag << ft_default; + return; + } + + if (FromFunction->getNumParams() != ToFunction->getNumParams()) { + PDiag << ft_parameter_arity << ToFunction->getNumParams() + << FromFunction->getNumParams(); + return; + } + + // Handle different parameter types. + unsigned ArgPos; + if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) { + PDiag << ft_parameter_mismatch << ArgPos + 1 + << ToFunction->getParamType(ArgPos) + << FromFunction->getParamType(ArgPos); + return; + } + + // Handle different return type. + if (!Context.hasSameType(FromFunction->getReturnType(), + ToFunction->getReturnType())) { + PDiag << ft_return_type << ToFunction->getReturnType() + << FromFunction->getReturnType(); + return; + } + + if (FromFunction->getTypeQuals() != ToFunction->getTypeQuals()) { + PDiag << ft_qualifer_mismatch << ToFunction->getTypeQuals() + << FromFunction->getTypeQuals(); + return; + } + + // Handle exception specification differences on canonical type (in C++17 + // onwards). + if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified()) + ->isNothrow() != + cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified()) + ->isNothrow()) { + PDiag << ft_noexcept; + return; + } + + // Unable to find a difference, so add no extra info. + PDiag << ft_default; +} + +/// FunctionParamTypesAreEqual - This routine checks two function proto types +/// for equality of their argument types. Caller has already checked that +/// they have same number of arguments. If the parameters are different, +/// ArgPos will have the parameter index of the first different parameter. +bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType, + const FunctionProtoType *NewType, + unsigned *ArgPos) { + for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(), + N = NewType->param_type_begin(), + E = OldType->param_type_end(); + O && (O != E); ++O, ++N) { + if (!Context.hasSameType(O->getUnqualifiedType(), + N->getUnqualifiedType())) { + if (ArgPos) + *ArgPos = O - OldType->param_type_begin(); + return false; + } + } + return true; +} + +/// 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, + CastKind &Kind, + CXXCastPath& BasePath, + bool IgnoreBaseAccess, + bool Diagnose) { + QualType FromType = From->getType(); + bool IsCStyleOrFunctionalCast = IgnoreBaseAccess; + + Kind = CK_BitCast; + + if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() && + From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) == + Expr::NPCK_ZeroExpression) { + if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy)) + DiagRuntimeBehavior(From->getExprLoc(), From, + PDiag(diag::warn_impcast_bool_to_null_pointer) + << ToType << From->getSourceRange()); + else if (!isUnevaluatedContext()) + Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer) + << ToType << From->getSourceRange(); + } + if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { + if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) { + QualType FromPointeeType = FromPtrType->getPointeeType(), + ToPointeeType = ToPtrType->getPointeeType(); + + if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && + !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { + // We must have a derived-to-base conversion. Check an + // ambiguous or inaccessible conversion. + unsigned InaccessibleID = 0; + unsigned AmbigiousID = 0; + if (Diagnose) { + InaccessibleID = diag::err_upcast_to_inaccessible_base; + AmbigiousID = diag::err_ambiguous_derived_to_base_conv; + } + if (CheckDerivedToBaseConversion( + FromPointeeType, ToPointeeType, InaccessibleID, AmbigiousID, + From->getExprLoc(), From->getSourceRange(), DeclarationName(), + &BasePath, IgnoreBaseAccess)) + return true; + + // The conversion was successful. + Kind = CK_DerivedToBase; + } + + if (Diagnose && !IsCStyleOrFunctionalCast && + FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) { + assert(getLangOpts().MSVCCompat && + "this should only be possible with MSVCCompat!"); + Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj) + << From->getSourceRange(); + } + } + } else if (const ObjCObjectPointerType *ToPtrType = + ToType->getAs<ObjCObjectPointerType>()) { + if (const ObjCObjectPointerType *FromPtrType = + FromType->getAs<ObjCObjectPointerType>()) { + // 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; + } else if (FromType->isBlockPointerType()) { + Kind = CK_BlockPointerToObjCPointerCast; + } else { + Kind = CK_CPointerToObjCPointerCast; + } + } else if (ToType->isBlockPointerType()) { + if (!FromType->isBlockPointerType()) + Kind = CK_AnyPointerToBlockPointerCast; + } + + // We shouldn't fall into this case unless it's valid for other + // reasons. + if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) + Kind = CK_NullToPointer; + + 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, + bool InOverloadResolution, + 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, + InOverloadResolution? Expr::NPC_ValueDependentIsNotNull + : Expr::NPC_ValueDependentIsNull)) { + 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); + + if (!Context.hasSameUnqualifiedType(FromClass, ToClass) && + IsDerivedFrom(From->getBeginLoc(), 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 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, + CastKind &Kind, + CXXCastPath &BasePath, + bool IgnoreBaseAccess) { + QualType FromType = From->getType(); + const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); + if (!FromPtrType) { + // This must be a null pointer to member pointer conversion + assert(From->isNullPointerConstant(Context, + Expr::NPC_ValueDependentIsNull) && + "Expr must be null pointer constant!"); + Kind = CK_NullToMemberPointer; + 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."); + + CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, + /*DetectVirtual=*/true); + bool DerivationOkay = + IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths); + assert(DerivationOkay && + "Should not have been called if derivation isn't OK."); + (void)DerivationOkay; + + if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). + getUnqualifiedType())) { + 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; + } + + if (!IgnoreBaseAccess) + CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, + Paths.front(), + diag::err_downcast_from_inaccessible_base); + + // Must be a base to derived member conversion. + BuildBasePathArray(Paths, BasePath); + Kind = CK_BaseToDerivedMemberPointer; + return false; +} + +/// Determine whether the lifetime conversion between the two given +/// qualifiers sets is nontrivial. +static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals, + Qualifiers ToQuals) { + // Converting anything to const __unsafe_unretained is trivial. + if (ToQuals.hasConst() && + ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone) + return false; + + return true; +} + +/// IsQualificationConversion - Determines whether the conversion from +/// an rvalue of type FromType to ToType is a qualification conversion +/// (C++ 4.4). +/// +/// \param ObjCLifetimeConversion Output parameter that will be set to indicate +/// when the qualification conversion involves a change in the Objective-C +/// object lifetime. +bool +Sema::IsQualificationConversion(QualType FromType, QualType ToType, + bool CStyle, bool &ObjCLifetimeConversion) { + FromType = Context.getCanonicalType(FromType); + ToType = Context.getCanonicalType(ToType); + ObjCLifetimeConversion = false; + + // If FromType and ToType are the same type, this is not a + // qualification conversion. + if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) + 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 (Context.UnwrapSimilarTypes(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; + + Qualifiers FromQuals = FromType.getQualifiers(); + Qualifiers ToQuals = ToType.getQualifiers(); + + // Ignore __unaligned qualifier if this type is void. + if (ToType.getUnqualifiedType()->isVoidType()) + FromQuals.removeUnaligned(); + + // Objective-C ARC: + // Check Objective-C lifetime conversions. + if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime() && + UnwrappedAnyPointer) { + if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) { + if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals)) + ObjCLifetimeConversion = true; + FromQuals.removeObjCLifetime(); + ToQuals.removeObjCLifetime(); + } else { + // Qualification conversions cannot cast between different + // Objective-C lifetime qualifiers. + return false; + } + } + + // Allow addition/removal of GC attributes but not changing GC attributes. + if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() && + (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) { + FromQuals.removeObjCGCAttr(); + ToQuals.removeObjCGCAttr(); + } + + // -- for every j > 0, if const is in cv 1,j then const is in cv + // 2,j, and similarly for volatile. + if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals)) + return false; + + // -- if the cv 1,j and cv 2,j are different, then const is in + // every cv for 0 < k < j. + if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() + && !PreviousToQualsIncludeConst) + return false; + + // Keep track of whether all prior cv-qualifiers in the "to" type + // include const. + PreviousToQualsIncludeConst + = PreviousToQualsIncludeConst && ToQuals.hasConst(); + } + + // Allows address space promotion by language rules implemented in + // Type::Qualifiers::isAddressSpaceSupersetOf. + Qualifiers FromQuals = FromType.getQualifiers(); + Qualifiers ToQuals = ToType.getQualifiers(); + if (!ToQuals.isAddressSpaceSupersetOf(FromQuals) && + !FromQuals.isAddressSpaceSupersetOf(ToQuals)) { + return false; + } + + // 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 && Context.hasSameUnqualifiedType(FromType,ToType); +} + +/// - Determine whether this is a conversion from a scalar type to an +/// atomic type. +/// +/// If successful, updates \c SCS's second and third steps in the conversion +/// sequence to finish the conversion. +static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType, + bool InOverloadResolution, + StandardConversionSequence &SCS, + bool CStyle) { + const AtomicType *ToAtomic = ToType->getAs<AtomicType>(); + if (!ToAtomic) + return false; + + StandardConversionSequence InnerSCS; + if (!IsStandardConversion(S, From, ToAtomic->getValueType(), + InOverloadResolution, InnerSCS, + CStyle, /*AllowObjCWritebackConversion=*/false)) + return false; + + SCS.Second = InnerSCS.Second; + SCS.setToType(1, InnerSCS.getToType(1)); + SCS.Third = InnerSCS.Third; + SCS.QualificationIncludesObjCLifetime + = InnerSCS.QualificationIncludesObjCLifetime; + SCS.setToType(2, InnerSCS.getToType(2)); + return true; +} + +static bool isFirstArgumentCompatibleWithType(ASTContext &Context, + CXXConstructorDecl *Constructor, + QualType Type) { + const FunctionProtoType *CtorType = + Constructor->getType()->getAs<FunctionProtoType>(); + if (CtorType->getNumParams() > 0) { + QualType FirstArg = CtorType->getParamType(0); + if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType())) + return true; + } + return false; +} + +static OverloadingResult +IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType, + CXXRecordDecl *To, + UserDefinedConversionSequence &User, + OverloadCandidateSet &CandidateSet, + bool AllowExplicit) { + CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion); + for (auto *D : S.LookupConstructors(To)) { + auto Info = getConstructorInfo(D); + if (!Info) + continue; + + bool Usable = !Info.Constructor->isInvalidDecl() && + S.isInitListConstructor(Info.Constructor) && + (AllowExplicit || !Info.Constructor->isExplicit()); + if (Usable) { + // If the first argument is (a reference to) the target type, + // suppress conversions. + bool SuppressUserConversions = isFirstArgumentCompatibleWithType( + S.Context, Info.Constructor, ToType); + if (Info.ConstructorTmpl) + S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl, + /*ExplicitArgs*/ nullptr, From, + CandidateSet, SuppressUserConversions); + else + S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From, + CandidateSet, SuppressUserConversions); + } + } + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + OverloadCandidateSet::iterator Best; + switch (auto Result = + CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) { + case OR_Deleted: + case OR_Success: { + // Record the standard conversion we used and the conversion function. + CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function); + QualType ThisType = Constructor->getThisType(); + // Initializer lists don't have conversions as such. + User.Before.setAsIdentityConversion(); + User.HadMultipleCandidates = HadMultipleCandidates; + User.ConversionFunction = Constructor; + User.FoundConversionFunction = Best->FoundDecl; + User.After.setAsIdentityConversion(); + User.After.setFromType(ThisType->getAs<PointerType>()->getPointeeType()); + User.After.setAllToTypes(ToType); + return Result; + } + + case OR_No_Viable_Function: + return OR_No_Viable_Function; + case OR_Ambiguous: + return OR_Ambiguous; + } + + llvm_unreachable("Invalid OverloadResult!"); +} + +/// 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 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 AllowObjCConversionOnExplicit true if the conversion should +/// allow an extra Objective-C pointer conversion on uses of explicit +/// constructors. Requires \c AllowExplicit to also be set. +static OverloadingResult +IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType, + UserDefinedConversionSequence &User, + OverloadCandidateSet &CandidateSet, + bool AllowExplicit, + bool AllowObjCConversionOnExplicit) { + assert(AllowExplicit || !AllowObjCConversionOnExplicit); + CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion); + + // Whether we will only visit constructors. + bool ConstructorsOnly = false; + + // If the type we are conversion to is a class type, enumerate its + // constructors. + if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { + // 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. + if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) || + (From->getType()->getAs<RecordType>() && + S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType))) + ConstructorsOnly = true; + + if (!S.isCompleteType(From->getExprLoc(), ToType)) { + // We're not going to find any constructors. + } else if (CXXRecordDecl *ToRecordDecl + = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { + + Expr **Args = &From; + unsigned NumArgs = 1; + bool ListInitializing = false; + if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) { + // But first, see if there is an init-list-constructor that will work. + OverloadingResult Result = IsInitializerListConstructorConversion( + S, From, ToType, ToRecordDecl, User, CandidateSet, AllowExplicit); + if (Result != OR_No_Viable_Function) + return Result; + // Never mind. + CandidateSet.clear( + OverloadCandidateSet::CSK_InitByUserDefinedConversion); + + // If we're list-initializing, we pass the individual elements as + // arguments, not the entire list. + Args = InitList->getInits(); + NumArgs = InitList->getNumInits(); + ListInitializing = true; + } + + for (auto *D : S.LookupConstructors(ToRecordDecl)) { + auto Info = getConstructorInfo(D); + if (!Info) + continue; + + bool Usable = !Info.Constructor->isInvalidDecl(); + if (ListInitializing) + Usable = Usable && (AllowExplicit || !Info.Constructor->isExplicit()); + else + Usable = Usable && + Info.Constructor->isConvertingConstructor(AllowExplicit); + if (Usable) { + bool SuppressUserConversions = !ConstructorsOnly; + if (SuppressUserConversions && ListInitializing) { + SuppressUserConversions = false; + if (NumArgs == 1) { + // If the first argument is (a reference to) the target type, + // suppress conversions. + SuppressUserConversions = isFirstArgumentCompatibleWithType( + S.Context, Info.Constructor, ToType); + } + } + if (Info.ConstructorTmpl) + S.AddTemplateOverloadCandidate( + Info.ConstructorTmpl, Info.FoundDecl, + /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs), + CandidateSet, SuppressUserConversions); + else + // Allow one user-defined conversion when user specifies a + // From->ToType conversion via an static cast (c-style, etc). + S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, + llvm::makeArrayRef(Args, NumArgs), + CandidateSet, SuppressUserConversions); + } + } + } + } + + // Enumerate conversion functions, if we're allowed to. + if (ConstructorsOnly || isa<InitListExpr>(From)) { + } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) { + // No conversion functions from incomplete types. + } 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. + const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions(); + for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { + DeclAccessPair FoundDecl = I.getPair(); + NamedDecl *D = FoundDecl.getDecl(); + CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + + CXXConversionDecl *Conv; + FunctionTemplateDecl *ConvTemplate; + if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) + Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); + else + Conv = cast<CXXConversionDecl>(D); + + if (AllowExplicit || !Conv->isExplicit()) { + if (ConvTemplate) + S.AddTemplateConversionCandidate(ConvTemplate, FoundDecl, + ActingContext, From, ToType, + CandidateSet, + AllowObjCConversionOnExplicit); + else + S.AddConversionCandidate(Conv, FoundDecl, ActingContext, + From, ToType, CandidateSet, + AllowObjCConversionOnExplicit); + } + } + } + } + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + OverloadCandidateSet::iterator Best; + switch (auto Result = + CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) { + case OR_Success: + case OR_Deleted: + // 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. + // + QualType ThisType = Constructor->getThisType(); + if (isa<InitListExpr>(From)) { + // Initializer lists don't have conversions as such. + User.Before.setAsIdentityConversion(); + } else { + if (Best->Conversions[0].isEllipsis()) + User.EllipsisConversion = true; + else { + User.Before = Best->Conversions[0].Standard; + User.EllipsisConversion = false; + } + } + User.HadMultipleCandidates = HadMultipleCandidates; + User.ConversionFunction = Constructor; + User.FoundConversionFunction = Best->FoundDecl; + User.After.setAsIdentityConversion(); + User.After.setFromType(ThisType->getAs<PointerType>()->getPointeeType()); + User.After.setAllToTypes(ToType); + return Result; + } + 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.HadMultipleCandidates = HadMultipleCandidates; + User.ConversionFunction = Conversion; + User.FoundConversionFunction = Best->FoundDecl; + User.EllipsisConversion = false; + + // 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 Result; + } + llvm_unreachable("Not a constructor or conversion function?"); + + case OR_No_Viable_Function: + return OR_No_Viable_Function; + + case OR_Ambiguous: + return OR_Ambiguous; + } + + llvm_unreachable("Invalid OverloadResult!"); +} + +bool +Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { + ImplicitConversionSequence ICS; + OverloadCandidateSet CandidateSet(From->getExprLoc(), + OverloadCandidateSet::CSK_Normal); + OverloadingResult OvResult = + IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined, + CandidateSet, false, false); + if (OvResult == OR_Ambiguous) + Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition) + << From->getType() << ToType << From->getSourceRange(); + else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) { + if (!RequireCompleteType(From->getBeginLoc(), ToType, + diag::err_typecheck_nonviable_condition_incomplete, + From->getType(), From->getSourceRange())) + Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition) + << false << From->getType() << From->getSourceRange() << ToType; + } else + return false; + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, From); + return true; +} + +/// Compare the user-defined conversion functions or constructors +/// of two user-defined conversion sequences to determine whether any ordering +/// is possible. +static ImplicitConversionSequence::CompareKind +compareConversionFunctions(Sema &S, FunctionDecl *Function1, + FunctionDecl *Function2) { + if (!S.getLangOpts().ObjC || !S.getLangOpts().CPlusPlus11) + return ImplicitConversionSequence::Indistinguishable; + + // Objective-C++: + // If both conversion functions are implicitly-declared conversions from + // a lambda closure type to a function pointer and a block pointer, + // respectively, always prefer the conversion to a function pointer, + // because the function pointer is more lightweight and is more likely + // to keep code working. + CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1); + if (!Conv1) + return ImplicitConversionSequence::Indistinguishable; + + CXXConversionDecl *Conv2 = dyn_cast<CXXConversionDecl>(Function2); + if (!Conv2) + return ImplicitConversionSequence::Indistinguishable; + + if (Conv1->getParent()->isLambda() && Conv2->getParent()->isLambda()) { + bool Block1 = Conv1->getConversionType()->isBlockPointerType(); + bool Block2 = Conv2->getConversionType()->isBlockPointerType(); + if (Block1 != Block2) + return Block1 ? ImplicitConversionSequence::Worse + : ImplicitConversionSequence::Better; + } + + return ImplicitConversionSequence::Indistinguishable; +} + +static bool hasDeprecatedStringLiteralToCharPtrConversion( + const ImplicitConversionSequence &ICS) { + return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) || + (ICS.isUserDefined() && + ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr); +} + +/// 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). +static ImplicitConversionSequence::CompareKind +CompareImplicitConversionSequences(Sema &S, SourceLocation Loc, + 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). + // + // C++0x [over.best.ics]p10: + // For the purpose of ranking implicit conversion sequences as + // described in 13.3.3.2, the ambiguous conversion sequence is + // treated as a user-defined sequence that is indistinguishable + // from any other user-defined conversion sequence. + + // String literal to 'char *' conversion has been deprecated in C++03. It has + // been removed from C++11. We still accept this conversion, if it happens at + // the best viable function. Otherwise, this conversion is considered worse + // than ellipsis conversion. Consider this as an extension; this is not in the + // standard. For example: + // + // int &f(...); // #1 + // void f(char*); // #2 + // void g() { int &r = f("foo"); } + // + // In C++03, we pick #2 as the best viable function. + // In C++11, we pick #1 as the best viable function, because ellipsis + // conversion is better than string-literal to char* conversion (since there + // is no such conversion in C++11). If there was no #1 at all or #1 couldn't + // convert arguments, #2 would be the best viable function in C++11. + // If the best viable function has this conversion, a warning will be issued + // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11. + + if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings && + hasDeprecatedStringLiteralToCharPtrConversion(ICS1) != + hasDeprecatedStringLiteralToCharPtrConversion(ICS2)) + return hasDeprecatedStringLiteralToCharPtrConversion(ICS1) + ? ImplicitConversionSequence::Worse + : ImplicitConversionSequence::Better; + + if (ICS1.getKindRank() < ICS2.getKindRank()) + return ImplicitConversionSequence::Better; + if (ICS2.getKindRank() < ICS1.getKindRank()) + return ImplicitConversionSequence::Worse; + + // The following checks require both conversion sequences to be of + // the same kind. + if (ICS1.getKind() != ICS2.getKind()) + return ImplicitConversionSequence::Indistinguishable; + + ImplicitConversionSequence::CompareKind Result = + ImplicitConversionSequence::Indistinguishable; + + // Two implicit conversion sequences of the same form are + // indistinguishable conversion sequences unless one of the + // following rules apply: (C++ 13.3.3.2p3): + + // List-initialization sequence L1 is a better conversion sequence than + // list-initialization sequence L2 if: + // - L1 converts to std::initializer_list<X> for some X and L2 does not, or, + // if not that, + // - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T", + // and N1 is smaller than N2., + // even if one of the other rules in this paragraph would otherwise apply. + if (!ICS1.isBad()) { + if (ICS1.isStdInitializerListElement() && + !ICS2.isStdInitializerListElement()) + return ImplicitConversionSequence::Better; + if (!ICS1.isStdInitializerListElement() && + ICS2.isStdInitializerListElement()) + return ImplicitConversionSequence::Worse; + } + + if (ICS1.isStandard()) + // Standard conversion sequence S1 is a better conversion sequence than + // standard conversion sequence S2 if [...] + Result = CompareStandardConversionSequences(S, Loc, + ICS1.Standard, ICS2.Standard); + else if (ICS1.isUserDefined()) { + // 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) + Result = CompareStandardConversionSequences(S, Loc, + ICS1.UserDefined.After, + ICS2.UserDefined.After); + else + Result = compareConversionFunctions(S, + ICS1.UserDefined.ConversionFunction, + ICS2.UserDefined.ConversionFunction); + } + + return Result; +} + +// Per 13.3.3.2p3, compare the given standard conversion sequences to +// determine if one is a proper subset of the other. +static ImplicitConversionSequence::CompareKind +compareStandardConversionSubsets(ASTContext &Context, + const StandardConversionSequence& SCS1, + const StandardConversionSequence& SCS2) { + ImplicitConversionSequence::CompareKind Result + = ImplicitConversionSequence::Indistinguishable; + + // the identity conversion sequence is considered to be a subsequence of + // any non-identity conversion sequence + if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion()) + return ImplicitConversionSequence::Better; + else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion()) + return ImplicitConversionSequence::Worse; + + if (SCS1.Second != SCS2.Second) { + if (SCS1.Second == ICK_Identity) + Result = ImplicitConversionSequence::Better; + else if (SCS2.Second == ICK_Identity) + Result = ImplicitConversionSequence::Worse; + else + return ImplicitConversionSequence::Indistinguishable; + } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1))) + return ImplicitConversionSequence::Indistinguishable; + + if (SCS1.Third == SCS2.Third) { + return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result + : ImplicitConversionSequence::Indistinguishable; + } + + if (SCS1.Third == ICK_Identity) + return Result == ImplicitConversionSequence::Worse + ? ImplicitConversionSequence::Indistinguishable + : ImplicitConversionSequence::Better; + + if (SCS2.Third == ICK_Identity) + return Result == ImplicitConversionSequence::Better + ? ImplicitConversionSequence::Indistinguishable + : ImplicitConversionSequence::Worse; + + return ImplicitConversionSequence::Indistinguishable; +} + +/// Determine whether one of the given reference bindings is better +/// than the other based on what kind of bindings they are. +static bool +isBetterReferenceBindingKind(const StandardConversionSequence &SCS1, + const StandardConversionSequence &SCS2) { + // 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 *either* S1 binds an rvalue reference + // to an rvalue and S2 binds an lvalue reference *or S1 binds an + // lvalue reference to a function lvalue and S2 binds an rvalue + // reference*. + // + // FIXME: Rvalue references. We're going rogue with the above edits, + // because the semantics in the current C++0x working paper (N3225 at the + // time of this writing) break the standard definition of std::forward + // and std::reference_wrapper when dealing with references to functions. + // Proposed wording changes submitted to CWG for consideration. + if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier || + SCS2.BindsImplicitObjectArgumentWithoutRefQualifier) + return false; + + return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue && + SCS2.IsLvalueReference) || + (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue && + !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue); +} + +/// 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). +static ImplicitConversionSequence::CompareKind +CompareStandardConversionSequences(Sema &S, SourceLocation Loc, + 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 (ImplicitConversionSequence::CompareKind CK + = compareStandardConversionSubsets(S.Context, SCS1, SCS2)) + return CK; + + // -- 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(S.Context); + bool SCS2ConvertsToVoid + = SCS2.isPointerConversionToVoidPointer(S.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(S, Loc, SCS1, SCS2)) + return DerivedCK; + } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid && + !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) { + // 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 = SCS1.getFromType(); + QualType FromType2 = SCS2.getFromType(); + + // 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 = S.Context.getArrayDecayedType(FromType1); + if (SCS2.First == ICK_Array_To_Pointer) + FromType2 = S.Context.getArrayDecayedType(FromType2); + + QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType(); + QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType(); + + if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) + return ImplicitConversionSequence::Worse; + + // Objective-C++: If one interface is more specific than the + // other, it is the better one. + const ObjCObjectPointerType* FromObjCPtr1 + = FromType1->getAs<ObjCObjectPointerType>(); + const ObjCObjectPointerType* FromObjCPtr2 + = FromType2->getAs<ObjCObjectPointerType>(); + if (FromObjCPtr1 && FromObjCPtr2) { + bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1, + FromObjCPtr2); + bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2, + FromObjCPtr1); + if (AssignLeft != AssignRight) { + return AssignLeft? ImplicitConversionSequence::Better + : ImplicitConversionSequence::Worse; + } + } + } + + // Compare based on qualification conversions (C++ 13.3.3.2p3, + // bullet 3). + if (ImplicitConversionSequence::CompareKind QualCK + = CompareQualificationConversions(S, SCS1, SCS2)) + return QualCK; + + if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { + // Check for a better reference binding based on the kind of bindings. + if (isBetterReferenceBindingKind(SCS1, SCS2)) + return ImplicitConversionSequence::Better; + else if (isBetterReferenceBindingKind(SCS2, SCS1)) + return 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 = SCS1.getToType(2); + QualType T2 = SCS2.getToType(2); + T1 = S.Context.getCanonicalType(T1); + T2 = S.Context.getCanonicalType(T2); + Qualifiers T1Quals, T2Quals; + QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals); + QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals); + if (UnqualT1 == UnqualT2) { + // Objective-C++ ARC: If the references refer to objects with different + // lifetimes, prefer bindings that don't change lifetime. + if (SCS1.ObjCLifetimeConversionBinding != + SCS2.ObjCLifetimeConversionBinding) { + return SCS1.ObjCLifetimeConversionBinding + ? ImplicitConversionSequence::Worse + : ImplicitConversionSequence::Better; + } + + // If the type is an array type, promote the element qualifiers to the + // type for comparison. + if (isa<ArrayType>(T1) && T1Quals) + T1 = S.Context.getQualifiedType(UnqualT1, T1Quals); + if (isa<ArrayType>(T2) && T2Quals) + T2 = S.Context.getQualifiedType(UnqualT2, T2Quals); + if (T2.isMoreQualifiedThan(T1)) + return ImplicitConversionSequence::Better; + else if (T1.isMoreQualifiedThan(T2)) + return ImplicitConversionSequence::Worse; + } + } + + // In Microsoft mode, prefer an integral conversion to a + // floating-to-integral conversion if the integral conversion + // is between types of the same size. + // For example: + // void f(float); + // void f(int); + // int main { + // long a; + // f(a); + // } + // Here, MSVC will call f(int) instead of generating a compile error + // as clang will do in standard mode. + if (S.getLangOpts().MSVCCompat && SCS1.Second == ICK_Integral_Conversion && + SCS2.Second == ICK_Floating_Integral && + S.Context.getTypeSize(SCS1.getFromType()) == + S.Context.getTypeSize(SCS1.getToType(2))) + return ImplicitConversionSequence::Better; + + // Prefer a compatible vector conversion over a lax vector conversion + // For example: + // + // typedef float __v4sf __attribute__((__vector_size__(16))); + // void f(vector float); + // void f(vector signed int); + // int main() { + // __v4sf a; + // f(a); + // } + // Here, we'd like to choose f(vector float) and not + // report an ambiguous call error + if (SCS1.Second == ICK_Vector_Conversion && + SCS2.Second == ICK_Vector_Conversion) { + bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes( + SCS1.getFromType(), SCS1.getToType(2)); + bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes( + SCS2.getFromType(), SCS2.getToType(2)); + + if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion) + return SCS1IsCompatibleVectorConversion + ? ImplicitConversionSequence::Better + : 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). +static ImplicitConversionSequence::CompareKind +CompareQualificationConversions(Sema &S, + 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 = SCS1.getToType(2); + QualType T2 = SCS2.getToType(2); + T1 = S.Context.getCanonicalType(T1); + T2 = S.Context.getCanonicalType(T2); + Qualifiers T1Quals, T2Quals; + QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals); + QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals); + + // If the types are the same, we won't learn anything by unwrapped + // them. + if (UnqualT1 == UnqualT2) + return ImplicitConversionSequence::Indistinguishable; + + // If the type is an array type, promote the element qualifiers to the type + // for comparison. + if (isa<ArrayType>(T1) && T1Quals) + T1 = S.Context.getQualifiedType(UnqualT1, T1Quals); + if (isa<ArrayType>(T2) && T2Quals) + T2 = S.Context.getQualifiedType(UnqualT2, T2Quals); + + ImplicitConversionSequence::CompareKind Result + = ImplicitConversionSequence::Indistinguishable; + + // Objective-C++ ARC: + // Prefer qualification conversions not involving a change in lifetime + // to qualification conversions that do not change lifetime. + if (SCS1.QualificationIncludesObjCLifetime != + SCS2.QualificationIncludesObjCLifetime) { + Result = SCS1.QualificationIncludesObjCLifetime + ? ImplicitConversionSequence::Worse + : ImplicitConversionSequence::Better; + } + + while (S.Context.UnwrapSimilarTypes(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 (S.Context.hasSameUnqualifiedType(T1, T2)) + 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.DeprecatedStringLiteralToCharPtr) + Result = ImplicitConversionSequence::Indistinguishable; + break; + + case ImplicitConversionSequence::Indistinguishable: + break; + + case ImplicitConversionSequence::Worse: + if (SCS2.DeprecatedStringLiteralToCharPtr) + 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. +static ImplicitConversionSequence::CompareKind +CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc, + const StandardConversionSequence& SCS1, + const StandardConversionSequence& SCS2) { + QualType FromType1 = SCS1.getFromType(); + QualType ToType1 = SCS1.getToType(1); + QualType FromType2 = SCS2.getFromType(); + QualType ToType2 = SCS2.getToType(1); + + // 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 = S.Context.getArrayDecayedType(FromType1); + if (SCS2.First == ICK_Array_To_Pointer) + FromType2 = S.Context.getArrayDecayedType(FromType2); + + // Canonicalize all of the types. + FromType1 = S.Context.getCanonicalType(FromType1); + ToType1 = S.Context.getCanonicalType(ToType1); + FromType2 = S.Context.getCanonicalType(FromType2); + ToType2 = S.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, + // + // 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(); + + // -- conversion of C* to B* is better than conversion of C* to A*, + if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { + if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1)) + return ImplicitConversionSequence::Worse; + } + + // -- conversion of B* to A* is better than conversion of C* to A*, + if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { + if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) + return ImplicitConversionSequence::Worse; + } + } else if (SCS1.Second == ICK_Pointer_Conversion && + SCS2.Second == ICK_Pointer_Conversion) { + const ObjCObjectPointerType *FromPtr1 + = FromType1->getAs<ObjCObjectPointerType>(); + const ObjCObjectPointerType *FromPtr2 + = FromType2->getAs<ObjCObjectPointerType>(); + const ObjCObjectPointerType *ToPtr1 + = ToType1->getAs<ObjCObjectPointerType>(); + const ObjCObjectPointerType *ToPtr2 + = ToType2->getAs<ObjCObjectPointerType>(); + + if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) { + // Apply the same conversion ranking rules for Objective-C pointer types + // that we do for C++ pointers to class types. However, we employ the + // Objective-C pseudo-subtyping relationship used for assignment of + // Objective-C pointer types. + bool FromAssignLeft + = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2); + bool FromAssignRight + = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1); + bool ToAssignLeft + = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2); + bool ToAssignRight + = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1); + + // A conversion to an a non-id object pointer type or qualified 'id' + // type is better than a conversion to 'id'. + if (ToPtr1->isObjCIdType() && + (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl())) + return ImplicitConversionSequence::Worse; + if (ToPtr2->isObjCIdType() && + (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl())) + return ImplicitConversionSequence::Better; + + // A conversion to a non-id object pointer type is better than a + // conversion to a qualified 'id' type + if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl()) + return ImplicitConversionSequence::Worse; + if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl()) + return ImplicitConversionSequence::Better; + + // A conversion to an a non-Class object pointer type or qualified 'Class' + // type is better than a conversion to 'Class'. + if (ToPtr1->isObjCClassType() && + (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl())) + return ImplicitConversionSequence::Worse; + if (ToPtr2->isObjCClassType() && + (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl())) + return ImplicitConversionSequence::Better; + + // A conversion to a non-Class object pointer type is better than a + // conversion to a qualified 'Class' type. + if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl()) + return ImplicitConversionSequence::Worse; + if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl()) + return ImplicitConversionSequence::Better; + + // -- "conversion of C* to B* is better than conversion of C* to A*," + if (S.Context.hasSameType(FromType1, FromType2) && + !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() && + (ToAssignLeft != ToAssignRight)) { + if (FromPtr1->isSpecialized()) { + // "conversion of B<A> * to B * is better than conversion of B * to + // C *. + bool IsFirstSame = + FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl(); + bool IsSecondSame = + FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl(); + if (IsFirstSame) { + if (!IsSecondSame) + return ImplicitConversionSequence::Better; + } else if (IsSecondSame) + return ImplicitConversionSequence::Worse; + } + return ToAssignLeft? ImplicitConversionSequence::Worse + : ImplicitConversionSequence::Better; + } + + // -- "conversion of B* to A* is better than conversion of C* to A*," + if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) && + (FromAssignLeft != FromAssignRight)) + return FromAssignLeft? ImplicitConversionSequence::Better + : ImplicitConversionSequence::Worse; + } + } + + // Ranking of member-pointer types. + if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && + FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && + ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { + const MemberPointerType * FromMemPointer1 = + FromType1->getAs<MemberPointerType>(); + const MemberPointerType * ToMemPointer1 = + ToType1->getAs<MemberPointerType>(); + const MemberPointerType * FromMemPointer2 = + FromType2->getAs<MemberPointerType>(); + const MemberPointerType * ToMemPointer2 = + ToType2->getAs<MemberPointerType>(); + const Type *FromPointeeType1 = FromMemPointer1->getClass(); + const Type *ToPointeeType1 = ToMemPointer1->getClass(); + const Type *FromPointeeType2 = FromMemPointer2->getClass(); + const Type *ToPointeeType2 = ToMemPointer2->getClass(); + QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); + QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); + QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); + QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); + // conversion of A::* to B::* is better than conversion of A::* to C::*, + if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { + if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2)) + return ImplicitConversionSequence::Worse; + else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1)) + return ImplicitConversionSequence::Better; + } + // conversion of B::* to C::* is better than conversion of A::* to C::* + if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { + if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1)) + return ImplicitConversionSequence::Worse; + } + } + + if (SCS1.Second == ICK_Derived_To_Base) { + // -- conversion of C to B is better than conversion of C to A, + // -- 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 (S.Context.hasSameUnqualifiedType(FromType1, FromType2) && + !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) { + if (S.IsDerivedFrom(Loc, ToType1, ToType2)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, ToType2, ToType1)) + return ImplicitConversionSequence::Worse; + } + + // -- conversion of B to A is better than conversion of C to A. + // -- 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 (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) && + S.Context.hasSameUnqualifiedType(ToType1, ToType2)) { + if (S.IsDerivedFrom(Loc, FromType2, FromType1)) + return ImplicitConversionSequence::Better; + else if (S.IsDerivedFrom(Loc, FromType1, FromType2)) + return ImplicitConversionSequence::Worse; + } + } + + return ImplicitConversionSequence::Indistinguishable; +} + +/// Determine whether the given type is valid, e.g., it is not an invalid +/// C++ class. +static bool isTypeValid(QualType T) { + if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) + return !Record->isInvalidDecl(); + + return true; +} + +/// CompareReferenceRelationship - Compare the two types T1 and T2 to +/// determine whether they are reference-related, +/// reference-compatible, reference-compatible with added +/// qualification, or incompatible, for use in C++ initialization by +/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference +/// type, and the first type (T1) is the pointee type of the reference +/// type being initialized. +Sema::ReferenceCompareResult +Sema::CompareReferenceRelationship(SourceLocation Loc, + QualType OrigT1, QualType OrigT2, + bool &DerivedToBase, + bool &ObjCConversion, + bool &ObjCLifetimeConversion) { + assert(!OrigT1->isReferenceType() && + "T1 must be the pointee type of the reference type"); + assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); + + QualType T1 = Context.getCanonicalType(OrigT1); + QualType T2 = Context.getCanonicalType(OrigT2); + Qualifiers T1Quals, T2Quals; + QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); + QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); + + // C++ [dcl.init.ref]p4: + // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is + // reference-related to "cv2 T2" if T1 is the same type as T2, or + // T1 is a base class of T2. + DerivedToBase = false; + ObjCConversion = false; + ObjCLifetimeConversion = false; + QualType ConvertedT2; + if (UnqualT1 == UnqualT2) { + // Nothing to do. + } else if (isCompleteType(Loc, OrigT2) && + isTypeValid(UnqualT1) && isTypeValid(UnqualT2) && + IsDerivedFrom(Loc, UnqualT2, UnqualT1)) + DerivedToBase = true; + else if (UnqualT1->isObjCObjectOrInterfaceType() && + UnqualT2->isObjCObjectOrInterfaceType() && + Context.canBindObjCObjectType(UnqualT1, UnqualT2)) + ObjCConversion = true; + else if (UnqualT2->isFunctionType() && + IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) + // C++1z [dcl.init.ref]p4: + // cv1 T1" is reference-compatible with "cv2 T2" if [...] T2 is "noexcept + // function" and T1 is "function" + // + // We extend this to also apply to 'noreturn', so allow any function + // conversion between function types. + return Ref_Compatible; + else + return Ref_Incompatible; + + // At this point, we know that T1 and T2 are reference-related (at + // least). + + // If the type is an array type, promote the element qualifiers to the type + // for comparison. + if (isa<ArrayType>(T1) && T1Quals) + T1 = Context.getQualifiedType(UnqualT1, T1Quals); + if (isa<ArrayType>(T2) && T2Quals) + T2 = Context.getQualifiedType(UnqualT2, T2Quals); + + // C++ [dcl.init.ref]p4: + // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is + // reference-related to T2 and cv1 is the same cv-qualification + // as, or greater cv-qualification than, cv2. For purposes of + // overload resolution, cases for which cv1 is greater + // cv-qualification than cv2 are identified as + // reference-compatible with added qualification (see 13.3.3.2). + // + // Note that we also require equivalence of Objective-C GC and address-space + // qualifiers when performing these computations, so that e.g., an int in + // address space 1 is not reference-compatible with an int in address + // space 2. + if (T1Quals.getObjCLifetime() != T2Quals.getObjCLifetime() && + T1Quals.compatiblyIncludesObjCLifetime(T2Quals)) { + if (isNonTrivialObjCLifetimeConversion(T2Quals, T1Quals)) + ObjCLifetimeConversion = true; + + T1Quals.removeObjCLifetime(); + T2Quals.removeObjCLifetime(); + } + + // MS compiler ignores __unaligned qualifier for references; do the same. + T1Quals.removeUnaligned(); + T2Quals.removeUnaligned(); + + if (T1Quals.compatiblyIncludes(T2Quals)) + return Ref_Compatible; + else + return Ref_Related; +} + +/// Look for a user-defined conversion to a value reference-compatible +/// with DeclType. Return true if something definite is found. +static bool +FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS, + QualType DeclType, SourceLocation DeclLoc, + Expr *Init, QualType T2, bool AllowRvalues, + bool AllowExplicit) { + assert(T2->isRecordType() && "Can only find conversions of record types."); + CXXRecordDecl *T2RecordDecl + = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl()); + + OverloadCandidateSet CandidateSet( + DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion); + const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions(); + for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { + NamedDecl *D = *I; + CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext()); + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + + FunctionTemplateDecl *ConvTemplate + = dyn_cast<FunctionTemplateDecl>(D); + CXXConversionDecl *Conv; + if (ConvTemplate) + Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); + else + Conv = cast<CXXConversionDecl>(D); + + // If this is an explicit conversion, and we're not allowed to consider + // explicit conversions, skip it. + if (!AllowExplicit && Conv->isExplicit()) + continue; + + if (AllowRvalues) { + bool DerivedToBase = false; + bool ObjCConversion = false; + bool ObjCLifetimeConversion = false; + + // If we are initializing an rvalue reference, don't permit conversion + // functions that return lvalues. + if (!ConvTemplate && DeclType->isRValueReferenceType()) { + const ReferenceType *RefType + = Conv->getConversionType()->getAs<LValueReferenceType>(); + if (RefType && !RefType->getPointeeType()->isFunctionType()) + continue; + } + + if (!ConvTemplate && + S.CompareReferenceRelationship( + DeclLoc, + Conv->getConversionType().getNonReferenceType() + .getUnqualifiedType(), + DeclType.getNonReferenceType().getUnqualifiedType(), + DerivedToBase, ObjCConversion, ObjCLifetimeConversion) == + Sema::Ref_Incompatible) + continue; + } else { + // If the conversion function doesn't return a reference type, + // it can't be considered for this conversion. An rvalue reference + // is only acceptable if its referencee is a function type. + + const ReferenceType *RefType = + Conv->getConversionType()->getAs<ReferenceType>(); + if (!RefType || + (!RefType->isLValueReferenceType() && + !RefType->getPointeeType()->isFunctionType())) + continue; + } + + if (ConvTemplate) + S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC, + Init, DeclType, CandidateSet, + /*AllowObjCConversionOnExplicit=*/false); + else + S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init, + DeclType, CandidateSet, + /*AllowObjCConversionOnExplicit=*/false); + } + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) { + case OR_Success: + // C++ [over.ics.ref]p1: + // + // [...] If the parameter binds directly to the result of + // applying a conversion function to the argument + // expression, the implicit conversion sequence is a + // user-defined conversion sequence (13.3.3.1.2), with the + // second standard conversion sequence either an identity + // conversion or, if the conversion function returns an + // entity of a type that is a derived class of the parameter + // type, a derived-to-base Conversion. + if (!Best->FinalConversion.DirectBinding) + return false; + + ICS.setUserDefined(); + ICS.UserDefined.Before = Best->Conversions[0].Standard; + ICS.UserDefined.After = Best->FinalConversion; + ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates; + ICS.UserDefined.ConversionFunction = Best->Function; + ICS.UserDefined.FoundConversionFunction = Best->FoundDecl; + ICS.UserDefined.EllipsisConversion = false; + assert(ICS.UserDefined.After.ReferenceBinding && + ICS.UserDefined.After.DirectBinding && + "Expected a direct reference binding!"); + return true; + + case OR_Ambiguous: + ICS.setAmbiguous(); + for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); + Cand != CandidateSet.end(); ++Cand) + if (Cand->Viable) + ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function); + return true; + + case OR_No_Viable_Function: + case OR_Deleted: + // There was no suitable conversion, or we found a deleted + // conversion; continue with other checks. + return false; + } + + llvm_unreachable("Invalid OverloadResult!"); +} + +/// Compute an implicit conversion sequence for reference +/// initialization. +static ImplicitConversionSequence +TryReferenceInit(Sema &S, Expr *Init, QualType DeclType, + SourceLocation DeclLoc, + bool SuppressUserConversions, + bool AllowExplicit) { + assert(DeclType->isReferenceType() && "Reference init needs a reference"); + + // Most paths end in a failed conversion. + ImplicitConversionSequence ICS; + ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); + + QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType(); + QualType T2 = Init->getType(); + + // If the initializer is the address of an overloaded function, try + // to resolve the overloaded function. If all goes well, T2 is the + // type of the resulting function. + if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { + DeclAccessPair Found; + if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, + false, Found)) + T2 = Fn->getType(); + } + + // Compute some basic properties of the types and the initializer. + bool isRValRef = DeclType->isRValueReferenceType(); + bool DerivedToBase = false; + bool ObjCConversion = false; + bool ObjCLifetimeConversion = false; + Expr::Classification InitCategory = Init->Classify(S.Context); + Sema::ReferenceCompareResult RefRelationship + = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase, + ObjCConversion, ObjCLifetimeConversion); + + + // C++0x [dcl.init.ref]p5: + // A reference to type "cv1 T1" is initialized by an expression + // of type "cv2 T2" as follows: + + // -- If reference is an lvalue reference and the initializer expression + if (!isRValRef) { + // -- is an lvalue (but is not a bit-field), and "cv1 T1" is + // reference-compatible with "cv2 T2," or + // + // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. + if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) { + // C++ [over.ics.ref]p1: + // When a parameter of reference type binds directly (8.5.3) + // to an argument expression, the implicit conversion sequence + // is the identity conversion, unless the argument expression + // has a type that is a derived class of the parameter type, + // in which case the implicit conversion sequence is a + // derived-to-base Conversion (13.3.3.1). + ICS.setStandard(); + ICS.Standard.First = ICK_Identity; + ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base + : ObjCConversion? ICK_Compatible_Conversion + : ICK_Identity; + ICS.Standard.Third = ICK_Identity; + ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); + ICS.Standard.setToType(0, T2); + ICS.Standard.setToType(1, T1); + ICS.Standard.setToType(2, T1); + ICS.Standard.ReferenceBinding = true; + ICS.Standard.DirectBinding = true; + ICS.Standard.IsLvalueReference = !isRValRef; + ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType(); + ICS.Standard.BindsToRvalue = false; + ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false; + ICS.Standard.ObjCLifetimeConversionBinding = ObjCLifetimeConversion; + ICS.Standard.CopyConstructor = nullptr; + ICS.Standard.DeprecatedStringLiteralToCharPtr = false; + + // Nothing more to do: the inaccessibility/ambiguity check for + // derived-to-base conversions is suppressed when we're + // computing the implicit conversion sequence (C++ + // [over.best.ics]p2). + return ICS; + } + + // -- has a class type (i.e., T2 is a class type), where T1 is + // not reference-related to T2, and can be implicitly + // converted to an lvalue of type "cv3 T3," where "cv1 T1" + // is reference-compatible with "cv3 T3" 92) (this + // conversion is selected by enumerating the applicable + // conversion functions (13.3.1.6) and choosing the best + // one through overload resolution (13.3)), + if (!SuppressUserConversions && T2->isRecordType() && + S.isCompleteType(DeclLoc, T2) && + RefRelationship == Sema::Ref_Incompatible) { + if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc, + Init, T2, /*AllowRvalues=*/false, + AllowExplicit)) + return ICS; + } + } + + // -- Otherwise, the reference shall be an lvalue reference to a + // non-volatile const type (i.e., cv1 shall be const), or the reference + // shall be an rvalue reference. + if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) + return ICS; + + // -- If the initializer expression + // + // -- is an xvalue, class prvalue, array prvalue or function + // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or + if (RefRelationship == Sema::Ref_Compatible && + (InitCategory.isXValue() || + (InitCategory.isPRValue() && (T2->isRecordType() || T2->isArrayType())) || + (InitCategory.isLValue() && T2->isFunctionType()))) { + ICS.setStandard(); + ICS.Standard.First = ICK_Identity; + ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base + : ObjCConversion? ICK_Compatible_Conversion + : ICK_Identity; + ICS.Standard.Third = ICK_Identity; + ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); + ICS.Standard.setToType(0, T2); + ICS.Standard.setToType(1, T1); + ICS.Standard.setToType(2, T1); + ICS.Standard.ReferenceBinding = true; + // In C++0x, this is always a direct binding. In C++98/03, it's a direct + // binding unless we're binding to a class prvalue. + // Note: Although xvalues wouldn't normally show up in C++98/03 code, we + // allow the use of rvalue references in C++98/03 for the benefit of + // standard library implementors; therefore, we need the xvalue check here. + ICS.Standard.DirectBinding = + S.getLangOpts().CPlusPlus11 || + !(InitCategory.isPRValue() || T2->isRecordType()); + ICS.Standard.IsLvalueReference = !isRValRef; + ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType(); + ICS.Standard.BindsToRvalue = InitCategory.isRValue(); + ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false; + ICS.Standard.ObjCLifetimeConversionBinding = ObjCLifetimeConversion; + ICS.Standard.CopyConstructor = nullptr; + ICS.Standard.DeprecatedStringLiteralToCharPtr = false; + return ICS; + } + + // -- has a class type (i.e., T2 is a class type), where T1 is not + // reference-related to T2, and can be implicitly converted to + // an xvalue, class prvalue, or function lvalue of type + // "cv3 T3", where "cv1 T1" is reference-compatible with + // "cv3 T3", + // + // then the reference is bound to the value of the initializer + // expression in the first case and to the result of the conversion + // in the second case (or, in either case, to an appropriate base + // class subobject). + if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && + T2->isRecordType() && S.isCompleteType(DeclLoc, T2) && + FindConversionForRefInit(S, ICS, DeclType, DeclLoc, + Init, T2, /*AllowRvalues=*/true, + AllowExplicit)) { + // In the second case, if the reference is an rvalue reference + // and the second standard conversion sequence of the + // user-defined conversion sequence includes an lvalue-to-rvalue + // conversion, the program is ill-formed. + if (ICS.isUserDefined() && isRValRef && + ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue) + ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); + + return ICS; + } + + // A temporary of function type cannot be created; don't even try. + if (T1->isFunctionType()) + return ICS; + + // -- Otherwise, a temporary of type "cv1 T1" is created and + // initialized from the initializer expression using the + // rules for a non-reference copy initialization (8.5). The + // reference is then bound to the temporary. If T1 is + // reference-related to T2, cv1 must be the same + // cv-qualification as, or greater cv-qualification than, + // cv2; otherwise, the program is ill-formed. + if (RefRelationship == Sema::Ref_Related) { + // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then + // we would be reference-compatible or reference-compatible with + // added qualification. But that wasn't the case, so the reference + // initialization fails. + // + // Note that we only want to check address spaces and cvr-qualifiers here. + // ObjC GC, lifetime and unaligned qualifiers aren't important. + Qualifiers T1Quals = T1.getQualifiers(); + Qualifiers T2Quals = T2.getQualifiers(); + T1Quals.removeObjCGCAttr(); + T1Quals.removeObjCLifetime(); + T2Quals.removeObjCGCAttr(); + T2Quals.removeObjCLifetime(); + // MS compiler ignores __unaligned qualifier for references; do the same. + T1Quals.removeUnaligned(); + T2Quals.removeUnaligned(); + if (!T1Quals.compatiblyIncludes(T2Quals)) + return ICS; + } + + // If at least one of the types is a class type, the types are not + // related, and we aren't allowed any user conversions, the + // reference binding fails. This case is important for breaking + // recursion, since TryImplicitConversion below will attempt to + // create a temporary through the use of a copy constructor. + if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && + (T1->isRecordType() || T2->isRecordType())) + return ICS; + + // If T1 is reference-related to T2 and the reference is an rvalue + // reference, the initializer expression shall not be an lvalue. + if (RefRelationship >= Sema::Ref_Related && + isRValRef && Init->Classify(S.Context).isLValue()) + return ICS; + + // C++ [over.ics.ref]p2: + // When a parameter of reference type is not bound directly to + // an argument expression, the conversion sequence is the one + // required to convert the argument expression to the + // underlying type of the reference according to + // 13.3.3.1. Conceptually, this conversion sequence corresponds + // to copy-initializing a temporary of the underlying type with + // the argument expression. Any difference in top-level + // cv-qualification is subsumed by the initialization itself + // and does not constitute a conversion. + ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions, + /*AllowExplicit=*/false, + /*InOverloadResolution=*/false, + /*CStyle=*/false, + /*AllowObjCWritebackConversion=*/false, + /*AllowObjCConversionOnExplicit=*/false); + + // Of course, that's still a reference binding. + if (ICS.isStandard()) { + ICS.Standard.ReferenceBinding = true; + ICS.Standard.IsLvalueReference = !isRValRef; + ICS.Standard.BindsToFunctionLvalue = false; + ICS.Standard.BindsToRvalue = true; + ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false; + ICS.Standard.ObjCLifetimeConversionBinding = false; + } else if (ICS.isUserDefined()) { + const ReferenceType *LValRefType = + ICS.UserDefined.ConversionFunction->getReturnType() + ->getAs<LValueReferenceType>(); + + // C++ [over.ics.ref]p3: + // Except for an implicit object parameter, for which see 13.3.1, a + // standard conversion sequence cannot be formed if it requires [...] + // binding an rvalue reference to an lvalue other than a function + // lvalue. + // Note that the function case is not possible here. + if (DeclType->isRValueReferenceType() && LValRefType) { + // FIXME: This is the wrong BadConversionSequence. The problem is binding + // an rvalue reference to a (non-function) lvalue, not binding an lvalue + // reference to an rvalue! + ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType); + return ICS; + } + + ICS.UserDefined.After.ReferenceBinding = true; + ICS.UserDefined.After.IsLvalueReference = !isRValRef; + ICS.UserDefined.After.BindsToFunctionLvalue = false; + ICS.UserDefined.After.BindsToRvalue = !LValRefType; + ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false; + ICS.UserDefined.After.ObjCLifetimeConversionBinding = false; + } + + return ICS; +} + +static ImplicitConversionSequence +TryCopyInitialization(Sema &S, Expr *From, QualType ToType, + bool SuppressUserConversions, + bool InOverloadResolution, + bool AllowObjCWritebackConversion, + bool AllowExplicit = false); + +/// TryListConversion - Try to copy-initialize a value of type ToType from the +/// initializer list From. +static ImplicitConversionSequence +TryListConversion(Sema &S, InitListExpr *From, QualType ToType, + bool SuppressUserConversions, + bool InOverloadResolution, + bool AllowObjCWritebackConversion) { + // C++11 [over.ics.list]p1: + // When an argument is an initializer list, it is not an expression and + // special rules apply for converting it to a parameter type. + + ImplicitConversionSequence Result; + Result.setBad(BadConversionSequence::no_conversion, From, ToType); + + // We need a complete type for what follows. Incomplete types can never be + // initialized from init lists. + if (!S.isCompleteType(From->getBeginLoc(), ToType)) + return Result; + + // Per DR1467: + // If the parameter type is a class X and the initializer list has a single + // element of type cv U, where U is X or a class derived from X, the + // implicit conversion sequence is the one required to convert the element + // to the parameter type. + // + // Otherwise, if the parameter type is a character array [... ] + // and the initializer list has a single element that is an + // appropriately-typed string literal (8.5.2 [dcl.init.string]), the + // implicit conversion sequence is the identity conversion. + if (From->getNumInits() == 1) { + if (ToType->isRecordType()) { + QualType InitType = From->getInit(0)->getType(); + if (S.Context.hasSameUnqualifiedType(InitType, ToType) || + S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType)) + return TryCopyInitialization(S, From->getInit(0), ToType, + SuppressUserConversions, + InOverloadResolution, + AllowObjCWritebackConversion); + } + // FIXME: Check the other conditions here: array of character type, + // initializer is a string literal. + if (ToType->isArrayType()) { + InitializedEntity Entity = + InitializedEntity::InitializeParameter(S.Context, ToType, + /*Consumed=*/false); + if (S.CanPerformCopyInitialization(Entity, From)) { + Result.setStandard(); + Result.Standard.setAsIdentityConversion(); + Result.Standard.setFromType(ToType); + Result.Standard.setAllToTypes(ToType); + return Result; + } + } + } + + // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below). + // C++11 [over.ics.list]p2: + // If the parameter type is std::initializer_list<X> or "array of X" and + // all the elements can be implicitly converted to X, the implicit + // conversion sequence is the worst conversion necessary to convert an + // element of the list to X. + // + // C++14 [over.ics.list]p3: + // Otherwise, if the parameter type is "array of N X", if the initializer + // list has exactly N elements or if it has fewer than N elements and X is + // default-constructible, and if all the elements of the initializer list + // can be implicitly converted to X, the implicit conversion sequence is + // the worst conversion necessary to convert an element of the list to X. + // + // FIXME: We're missing a lot of these checks. + bool toStdInitializerList = false; + QualType X; + if (ToType->isArrayType()) + X = S.Context.getAsArrayType(ToType)->getElementType(); + else + toStdInitializerList = S.isStdInitializerList(ToType, &X); + if (!X.isNull()) { + for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) { + Expr *Init = From->getInit(i); + ImplicitConversionSequence ICS = + TryCopyInitialization(S, Init, X, SuppressUserConversions, + InOverloadResolution, + AllowObjCWritebackConversion); + // If a single element isn't convertible, fail. + if (ICS.isBad()) { + Result = ICS; + break; + } + // Otherwise, look for the worst conversion. + if (Result.isBad() || CompareImplicitConversionSequences( + S, From->getBeginLoc(), ICS, Result) == + ImplicitConversionSequence::Worse) + Result = ICS; + } + + // For an empty list, we won't have computed any conversion sequence. + // Introduce the identity conversion sequence. + if (From->getNumInits() == 0) { + Result.setStandard(); + Result.Standard.setAsIdentityConversion(); + Result.Standard.setFromType(ToType); + Result.Standard.setAllToTypes(ToType); + } + + Result.setStdInitializerListElement(toStdInitializerList); + return Result; + } + + // C++14 [over.ics.list]p4: + // C++11 [over.ics.list]p3: + // Otherwise, if the parameter is a non-aggregate class X and overload + // resolution chooses a single best constructor [...] the implicit + // conversion sequence is a user-defined conversion sequence. If multiple + // constructors are viable but none is better than the others, the + // implicit conversion sequence is a user-defined conversion sequence. + if (ToType->isRecordType() && !ToType->isAggregateType()) { + // This function can deal with initializer lists. + return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions, + /*AllowExplicit=*/false, + InOverloadResolution, /*CStyle=*/false, + AllowObjCWritebackConversion, + /*AllowObjCConversionOnExplicit=*/false); + } + + // C++14 [over.ics.list]p5: + // C++11 [over.ics.list]p4: + // Otherwise, if the parameter has an aggregate type which can be + // initialized from the initializer list [...] the implicit conversion + // sequence is a user-defined conversion sequence. + if (ToType->isAggregateType()) { + // Type is an aggregate, argument is an init list. At this point it comes + // down to checking whether the initialization works. + // FIXME: Find out whether this parameter is consumed or not. + // FIXME: Expose SemaInit's aggregate initialization code so that we don't + // need to call into the initialization code here; overload resolution + // should not be doing that. + InitializedEntity Entity = + InitializedEntity::InitializeParameter(S.Context, ToType, + /*Consumed=*/false); + if (S.CanPerformCopyInitialization(Entity, From)) { + Result.setUserDefined(); + Result.UserDefined.Before.setAsIdentityConversion(); + // Initializer lists don't have a type. + Result.UserDefined.Before.setFromType(QualType()); + Result.UserDefined.Before.setAllToTypes(QualType()); + + Result.UserDefined.After.setAsIdentityConversion(); + Result.UserDefined.After.setFromType(ToType); + Result.UserDefined.After.setAllToTypes(ToType); + Result.UserDefined.ConversionFunction = nullptr; + } + return Result; + } + + // C++14 [over.ics.list]p6: + // C++11 [over.ics.list]p5: + // Otherwise, if the parameter is a reference, see 13.3.3.1.4. + if (ToType->isReferenceType()) { + // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't + // mention initializer lists in any way. So we go by what list- + // initialization would do and try to extrapolate from that. + + QualType T1 = ToType->getAs<ReferenceType>()->getPointeeType(); + + // If the initializer list has a single element that is reference-related + // to the parameter type, we initialize the reference from that. + if (From->getNumInits() == 1) { + Expr *Init = From->getInit(0); + + QualType T2 = Init->getType(); + + // If the initializer is the address of an overloaded function, try + // to resolve the overloaded function. If all goes well, T2 is the + // type of the resulting function. + if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { + DeclAccessPair Found; + if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction( + Init, ToType, false, Found)) + T2 = Fn->getType(); + } + + // Compute some basic properties of the types and the initializer. + bool dummy1 = false; + bool dummy2 = false; + bool dummy3 = false; + Sema::ReferenceCompareResult RefRelationship = + S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2, dummy1, + dummy2, dummy3); + + if (RefRelationship >= Sema::Ref_Related) { + return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(), + SuppressUserConversions, + /*AllowExplicit=*/false); + } + } + + // Otherwise, we bind the reference to a temporary created from the + // initializer list. + Result = TryListConversion(S, From, T1, SuppressUserConversions, + InOverloadResolution, + AllowObjCWritebackConversion); + if (Result.isFailure()) + return Result; + assert(!Result.isEllipsis() && + "Sub-initialization cannot result in ellipsis conversion."); + + // Can we even bind to a temporary? + if (ToType->isRValueReferenceType() || + (T1.isConstQualified() && !T1.isVolatileQualified())) { + StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard : + Result.UserDefined.After; + SCS.ReferenceBinding = true; + SCS.IsLvalueReference = ToType->isLValueReferenceType(); + SCS.BindsToRvalue = true; + SCS.BindsToFunctionLvalue = false; + SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false; + SCS.ObjCLifetimeConversionBinding = false; + } else + Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue, + From, ToType); + return Result; + } + + // C++14 [over.ics.list]p7: + // C++11 [over.ics.list]p6: + // Otherwise, if the parameter type is not a class: + if (!ToType->isRecordType()) { + // - if the initializer list has one element that is not itself an + // initializer list, the implicit conversion sequence is the one + // required to convert the element to the parameter type. + unsigned NumInits = From->getNumInits(); + if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0))) + Result = TryCopyInitialization(S, From->getInit(0), ToType, + SuppressUserConversions, + InOverloadResolution, + AllowObjCWritebackConversion); + // - if the initializer list has no elements, the implicit conversion + // sequence is the identity conversion. + else if (NumInits == 0) { + Result.setStandard(); + Result.Standard.setAsIdentityConversion(); + Result.Standard.setFromType(ToType); + Result.Standard.setAllToTypes(ToType); + } + return Result; + } + + // C++14 [over.ics.list]p8: + // C++11 [over.ics.list]p7: + // In all cases other than those enumerated above, no conversion is possible + return Result; +} + +/// 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. +static ImplicitConversionSequence +TryCopyInitialization(Sema &S, Expr *From, QualType ToType, + bool SuppressUserConversions, + bool InOverloadResolution, + bool AllowObjCWritebackConversion, + bool AllowExplicit) { + if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From)) + return TryListConversion(S, FromInitList, ToType, SuppressUserConversions, + InOverloadResolution,AllowObjCWritebackConversion); + + if (ToType->isReferenceType()) + return TryReferenceInit(S, From, ToType, + /*FIXME:*/ From->getBeginLoc(), + SuppressUserConversions, AllowExplicit); + + return TryImplicitConversion(S, From, ToType, + SuppressUserConversions, + /*AllowExplicit=*/false, + InOverloadResolution, + /*CStyle=*/false, + AllowObjCWritebackConversion, + /*AllowObjCConversionOnExplicit=*/false); +} + +static bool TryCopyInitialization(const CanQualType FromQTy, + const CanQualType ToQTy, + Sema &S, + SourceLocation Loc, + ExprValueKind FromVK) { + OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK); + ImplicitConversionSequence ICS = + TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false); + + return !ICS.isBad(); +} + +/// TryObjectArgumentInitialization - Try to initialize the object +/// parameter of the given member function (@c Method) from the +/// expression @p From. +static ImplicitConversionSequence +TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType, + Expr::Classification FromClassification, + CXXMethodDecl *Method, + CXXRecordDecl *ActingContext) { + QualType ClassType = S.Context.getTypeDeclType(ActingContext); + // [class.dtor]p2: A destructor can be invoked for a const, volatile or + // const volatile object. + Qualifiers Quals; + if (isa<CXXDestructorDecl>(Method)) { + Quals.addConst(); + Quals.addVolatile(); + } else { + Quals = Method->getTypeQualifiers(); + } + + QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals); + + // Set up the conversion sequence as a "bad" conversion, to allow us + // to exit early. + ImplicitConversionSequence ICS; + + // We need to have an object of class type. + if (const PointerType *PT = FromType->getAs<PointerType>()) { + FromType = PT->getPointeeType(); + + // When we had a pointer, it's implicitly dereferenced, so we + // better have an lvalue. + assert(FromClassification.isLValue()); + } + + assert(FromType->isRecordType()); + + // C++0x [over.match.funcs]p4: + // For non-static member functions, the type of the implicit object + // parameter is + // + // - "lvalue reference to cv X" for functions declared without a + // ref-qualifier or with the & ref-qualifier + // - "rvalue reference to cv X" for functions declared with the && + // ref-qualifier + // + // where X is the class of which the function is a member and cv is the + // cv-qualification on the member function declaration. + // + // However, when finding an implicit conversion sequence for the argument, we + // are not allowed to 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. + QualType FromTypeCanon = S.Context.getCanonicalType(FromType); + if (ImplicitParamType.getCVRQualifiers() + != FromTypeCanon.getLocalCVRQualifiers() && + !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { + ICS.setBad(BadConversionSequence::bad_qualifiers, + FromType, ImplicitParamType); + return ICS; + } + + // Check that we have either the same type or a derived type. It + // affects the conversion rank. + QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType); + ImplicitConversionKind SecondKind; + if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { + SecondKind = ICK_Identity; + } else if (S.IsDerivedFrom(Loc, FromType, ClassType)) + SecondKind = ICK_Derived_To_Base; + else { + ICS.setBad(BadConversionSequence::unrelated_class, + FromType, ImplicitParamType); + return ICS; + } + + // Check the ref-qualifier. + switch (Method->getRefQualifier()) { + case RQ_None: + // Do nothing; we don't care about lvalueness or rvalueness. + break; + + case RQ_LValue: + if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) { + // non-const lvalue reference cannot bind to an rvalue + ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType, + ImplicitParamType); + return ICS; + } + break; + + case RQ_RValue: + if (!FromClassification.isRValue()) { + // rvalue reference cannot bind to an lvalue + ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType, + ImplicitParamType); + return ICS; + } + break; + } + + // Success. Mark this as a reference binding. + ICS.setStandard(); + ICS.Standard.setAsIdentityConversion(); + ICS.Standard.Second = SecondKind; + ICS.Standard.setFromType(FromType); + ICS.Standard.setAllToTypes(ImplicitParamType); + ICS.Standard.ReferenceBinding = true; + ICS.Standard.DirectBinding = true; + ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue; + ICS.Standard.BindsToFunctionLvalue = false; + ICS.Standard.BindsToRvalue = FromClassification.isRValue(); + ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier + = (Method->getRefQualifier() == RQ_None); + return ICS; +} + +/// PerformObjectArgumentInitialization - Perform initialization of +/// the implicit object parameter for the given Method with the given +/// expression. +ExprResult +Sema::PerformObjectArgumentInitialization(Expr *From, + NestedNameSpecifier *Qualifier, + NamedDecl *FoundDecl, + CXXMethodDecl *Method) { + QualType FromRecordType, DestType; + QualType ImplicitParamRecordType = + Method->getThisType()->getAs<PointerType>()->getPointeeType(); + + Expr::Classification FromClassification; + if (const PointerType *PT = From->getType()->getAs<PointerType>()) { + FromRecordType = PT->getPointeeType(); + DestType = Method->getThisType(); + FromClassification = Expr::Classification::makeSimpleLValue(); + } else { + FromRecordType = From->getType(); + DestType = ImplicitParamRecordType; + FromClassification = From->Classify(Context); + + // When performing member access on an rvalue, materialize a temporary. + if (From->isRValue()) { + From = CreateMaterializeTemporaryExpr(FromRecordType, From, + Method->getRefQualifier() != + RefQualifierKind::RQ_RValue); + } + } + + // Note that we always use the true parent context when performing + // the actual argument initialization. + ImplicitConversionSequence ICS = TryObjectArgumentInitialization( + *this, From->getBeginLoc(), From->getType(), FromClassification, Method, + Method->getParent()); + if (ICS.isBad()) { + switch (ICS.Bad.Kind) { + case BadConversionSequence::bad_qualifiers: { + Qualifiers FromQs = FromRecordType.getQualifiers(); + Qualifiers ToQs = DestType.getQualifiers(); + unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); + if (CVR) { + Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr) + << Method->getDeclName() << FromRecordType << (CVR - 1) + << From->getSourceRange(); + Diag(Method->getLocation(), diag::note_previous_decl) + << Method->getDeclName(); + return ExprError(); + } + break; + } + + case BadConversionSequence::lvalue_ref_to_rvalue: + case BadConversionSequence::rvalue_ref_to_lvalue: { + bool IsRValueQualified = + Method->getRefQualifier() == RefQualifierKind::RQ_RValue; + Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref) + << Method->getDeclName() << FromClassification.isRValue() + << IsRValueQualified; + Diag(Method->getLocation(), diag::note_previous_decl) + << Method->getDeclName(); + return ExprError(); + } + + case BadConversionSequence::no_conversion: + case BadConversionSequence::unrelated_class: + break; + } + + return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type) + << ImplicitParamRecordType << FromRecordType + << From->getSourceRange(); + } + + if (ICS.Standard.Second == ICK_Derived_To_Base) { + ExprResult FromRes = + PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); + if (FromRes.isInvalid()) + return ExprError(); + From = FromRes.get(); + } + + if (!Context.hasSameType(From->getType(), DestType)) { + if (From->getType().getAddressSpace() != DestType.getAddressSpace()) + From = ImpCastExprToType(From, DestType, CK_AddressSpaceConversion, + From->getValueKind()).get(); + else + From = ImpCastExprToType(From, DestType, CK_NoOp, + From->getValueKind()).get(); + } + return From; +} + +/// TryContextuallyConvertToBool - Attempt to contextually convert the +/// expression From to bool (C++0x [conv]p3). +static ImplicitConversionSequence +TryContextuallyConvertToBool(Sema &S, Expr *From) { + return TryImplicitConversion(S, From, S.Context.BoolTy, + /*SuppressUserConversions=*/false, + /*AllowExplicit=*/true, + /*InOverloadResolution=*/false, + /*CStyle=*/false, + /*AllowObjCWritebackConversion=*/false, + /*AllowObjCConversionOnExplicit=*/false); +} + +/// PerformContextuallyConvertToBool - Perform a contextual conversion +/// of the expression From to bool (C++0x [conv]p3). +ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) { + if (checkPlaceholderForOverload(*this, From)) + return ExprError(); + + ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From); + if (!ICS.isBad()) + return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); + + if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) + return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition) + << From->getType() << From->getSourceRange(); + return ExprError(); +} + +/// Check that the specified conversion is permitted in a converted constant +/// expression, according to C++11 [expr.const]p3. Return true if the conversion +/// is acceptable. +static bool CheckConvertedConstantConversions(Sema &S, + StandardConversionSequence &SCS) { + // Since we know that the target type is an integral or unscoped enumeration + // type, most conversion kinds are impossible. All possible First and Third + // conversions are fine. + switch (SCS.Second) { + case ICK_Identity: + case ICK_Function_Conversion: + case ICK_Integral_Promotion: + case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere. + case ICK_Zero_Queue_Conversion: + return true; + + case ICK_Boolean_Conversion: + // Conversion from an integral or unscoped enumeration type to bool is + // classified as ICK_Boolean_Conversion, but it's also arguably an integral + // conversion, so we allow it in a converted constant expression. + // + // FIXME: Per core issue 1407, we should not allow this, but that breaks + // a lot of popular code. We should at least add a warning for this + // (non-conforming) extension. + return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() && + SCS.getToType(2)->isBooleanType(); + + case ICK_Pointer_Conversion: + case ICK_Pointer_Member: + // C++1z: null pointer conversions and null member pointer conversions are + // only permitted if the source type is std::nullptr_t. + return SCS.getFromType()->isNullPtrType(); + + case ICK_Floating_Promotion: + case ICK_Complex_Promotion: + case ICK_Floating_Conversion: + case ICK_Complex_Conversion: + case ICK_Floating_Integral: + case ICK_Compatible_Conversion: + case ICK_Derived_To_Base: + case ICK_Vector_Conversion: + case ICK_Vector_Splat: + case ICK_Complex_Real: + case ICK_Block_Pointer_Conversion: + case ICK_TransparentUnionConversion: + case ICK_Writeback_Conversion: + case ICK_Zero_Event_Conversion: + case ICK_C_Only_Conversion: + case ICK_Incompatible_Pointer_Conversion: + return false; + + case ICK_Lvalue_To_Rvalue: + case ICK_Array_To_Pointer: + case ICK_Function_To_Pointer: + llvm_unreachable("found a first conversion kind in Second"); + + case ICK_Qualification: + llvm_unreachable("found a third conversion kind in Second"); + + case ICK_Num_Conversion_Kinds: + break; + } + + llvm_unreachable("unknown conversion kind"); +} + +/// CheckConvertedConstantExpression - Check that the expression From is a +/// converted constant expression of type T, perform the conversion and produce +/// the converted expression, per C++11 [expr.const]p3. +static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From, + QualType T, APValue &Value, + Sema::CCEKind CCE, + bool RequireInt) { + assert(S.getLangOpts().CPlusPlus11 && + "converted constant expression outside C++11"); + + if (checkPlaceholderForOverload(S, From)) + return ExprError(); + + // C++1z [expr.const]p3: + // A converted constant expression of type T is an expression, + // implicitly converted to type T, where the converted + // expression is a constant expression and the implicit conversion + // sequence contains only [... list of conversions ...]. + // C++1z [stmt.if]p2: + // If the if statement is of the form if constexpr, the value of the + // condition shall be a contextually converted constant expression of type + // bool. + ImplicitConversionSequence ICS = + CCE == Sema::CCEK_ConstexprIf + ? TryContextuallyConvertToBool(S, From) + : TryCopyInitialization(S, From, T, + /*SuppressUserConversions=*/false, + /*InOverloadResolution=*/false, + /*AllowObjcWritebackConversion=*/false, + /*AllowExplicit=*/false); + StandardConversionSequence *SCS = nullptr; + switch (ICS.getKind()) { + case ImplicitConversionSequence::StandardConversion: + SCS = &ICS.Standard; + break; + case ImplicitConversionSequence::UserDefinedConversion: + // We are converting to a non-class type, so the Before sequence + // must be trivial. + SCS = &ICS.UserDefined.After; + break; + case ImplicitConversionSequence::AmbiguousConversion: + case ImplicitConversionSequence::BadConversion: + if (!S.DiagnoseMultipleUserDefinedConversion(From, T)) + return S.Diag(From->getBeginLoc(), + diag::err_typecheck_converted_constant_expression) + << From->getType() << From->getSourceRange() << T; + return ExprError(); + + case ImplicitConversionSequence::EllipsisConversion: + llvm_unreachable("ellipsis conversion in converted constant expression"); + } + + // Check that we would only use permitted conversions. + if (!CheckConvertedConstantConversions(S, *SCS)) { + return S.Diag(From->getBeginLoc(), + diag::err_typecheck_converted_constant_expression_disallowed) + << From->getType() << From->getSourceRange() << T; + } + // [...] and where the reference binding (if any) binds directly. + if (SCS->ReferenceBinding && !SCS->DirectBinding) { + return S.Diag(From->getBeginLoc(), + diag::err_typecheck_converted_constant_expression_indirect) + << From->getType() << From->getSourceRange() << T; + } + + ExprResult Result = + S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting); + if (Result.isInvalid()) + return Result; + + // Check for a narrowing implicit conversion. + APValue PreNarrowingValue; + QualType PreNarrowingType; + switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue, + PreNarrowingType)) { + case NK_Dependent_Narrowing: + // Implicit conversion to a narrower type, but the expression is + // value-dependent so we can't tell whether it's actually narrowing. + case NK_Variable_Narrowing: + // Implicit conversion to a narrower type, and the value is not a constant + // expression. We'll diagnose this in a moment. + case NK_Not_Narrowing: + break; + + case NK_Constant_Narrowing: + S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing) + << CCE << /*Constant*/ 1 + << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T; + break; + + case NK_Type_Narrowing: + S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing) + << CCE << /*Constant*/ 0 << From->getType() << T; + break; + } + + if (Result.get()->isValueDependent()) { + Value = APValue(); + return Result; + } + + // Check the expression is a constant expression. + SmallVector<PartialDiagnosticAt, 8> Notes; + Expr::EvalResult Eval; + Eval.Diag = &Notes; + Expr::ConstExprUsage Usage = CCE == Sema::CCEK_TemplateArg + ? Expr::EvaluateForMangling + : Expr::EvaluateForCodeGen; + + if (!Result.get()->EvaluateAsConstantExpr(Eval, Usage, S.Context) || + (RequireInt && !Eval.Val.isInt())) { + // The expression can't be folded, so we can't keep it at this position in + // the AST. + Result = ExprError(); + } else { + Value = Eval.Val; + + if (Notes.empty()) { + // It's a constant expression. + return ConstantExpr::Create(S.Context, Result.get()); + } + } + + // It's not a constant expression. Produce an appropriate diagnostic. + if (Notes.size() == 1 && + Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) + S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE; + else { + S.Diag(From->getBeginLoc(), diag::err_expr_not_cce) + << CCE << From->getSourceRange(); + for (unsigned I = 0; I < Notes.size(); ++I) + S.Diag(Notes[I].first, Notes[I].second); + } + return ExprError(); +} + +ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T, + APValue &Value, CCEKind CCE) { + return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false); +} + +ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T, + llvm::APSInt &Value, + CCEKind CCE) { + assert(T->isIntegralOrEnumerationType() && "unexpected converted const type"); + + APValue V; + auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true); + if (!R.isInvalid() && !R.get()->isValueDependent()) + Value = V.getInt(); + return R; +} + + +/// dropPointerConversions - If the given standard conversion sequence +/// involves any pointer conversions, remove them. This may change +/// the result type of the conversion sequence. +static void dropPointerConversion(StandardConversionSequence &SCS) { + if (SCS.Second == ICK_Pointer_Conversion) { + SCS.Second = ICK_Identity; + SCS.Third = ICK_Identity; + SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0]; + } +} + +/// TryContextuallyConvertToObjCPointer - Attempt to contextually +/// convert the expression From to an Objective-C pointer type. +static ImplicitConversionSequence +TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) { + // Do an implicit conversion to 'id'. + QualType Ty = S.Context.getObjCIdType(); + ImplicitConversionSequence ICS + = TryImplicitConversion(S, From, Ty, + // FIXME: Are these flags correct? + /*SuppressUserConversions=*/false, + /*AllowExplicit=*/true, + /*InOverloadResolution=*/false, + /*CStyle=*/false, + /*AllowObjCWritebackConversion=*/false, + /*AllowObjCConversionOnExplicit=*/true); + + // Strip off any final conversions to 'id'. + switch (ICS.getKind()) { + case ImplicitConversionSequence::BadConversion: + case ImplicitConversionSequence::AmbiguousConversion: + case ImplicitConversionSequence::EllipsisConversion: + break; + + case ImplicitConversionSequence::UserDefinedConversion: + dropPointerConversion(ICS.UserDefined.After); + break; + + case ImplicitConversionSequence::StandardConversion: + dropPointerConversion(ICS.Standard); + break; + } + + return ICS; +} + +/// PerformContextuallyConvertToObjCPointer - Perform a contextual +/// conversion of the expression From to an Objective-C pointer type. +/// Returns a valid but null ExprResult if no conversion sequence exists. +ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) { + if (checkPlaceholderForOverload(*this, From)) + return ExprError(); + + QualType Ty = Context.getObjCIdType(); + ImplicitConversionSequence ICS = + TryContextuallyConvertToObjCPointer(*this, From); + if (!ICS.isBad()) + return PerformImplicitConversion(From, Ty, ICS, AA_Converting); + return ExprResult(); +} + +/// Determine whether the provided type is an integral type, or an enumeration +/// type of a permitted flavor. +bool Sema::ICEConvertDiagnoser::match(QualType T) { + return AllowScopedEnumerations ? T->isIntegralOrEnumerationType() + : T->isIntegralOrUnscopedEnumerationType(); +} + +static ExprResult +diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From, + Sema::ContextualImplicitConverter &Converter, + QualType T, UnresolvedSetImpl &ViableConversions) { + + if (Converter.Suppress) + return ExprError(); + + Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange(); + for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { + CXXConversionDecl *Conv = + cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl()); + QualType ConvTy = Conv->getConversionType().getNonReferenceType(); + Converter.noteAmbiguous(SemaRef, Conv, ConvTy); + } + return From; +} + +static bool +diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From, + Sema::ContextualImplicitConverter &Converter, + QualType T, bool HadMultipleCandidates, + UnresolvedSetImpl &ExplicitConversions) { + if (ExplicitConversions.size() == 1 && !Converter.Suppress) { + DeclAccessPair Found = ExplicitConversions[0]; + CXXConversionDecl *Conversion = + cast<CXXConversionDecl>(Found->getUnderlyingDecl()); + + // The user probably meant to invoke the given explicit + // conversion; use it. + QualType ConvTy = Conversion->getConversionType().getNonReferenceType(); + std::string TypeStr; + ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy()); + + Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy) + << FixItHint::CreateInsertion(From->getBeginLoc(), + "static_cast<" + TypeStr + ">(") + << FixItHint::CreateInsertion( + SemaRef.getLocForEndOfToken(From->getEndLoc()), ")"); + Converter.noteExplicitConv(SemaRef, Conversion, ConvTy); + + // If we aren't in a SFINAE context, build a call to the + // explicit conversion function. + if (SemaRef.isSFINAEContext()) + return true; + + SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found); + ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion, + HadMultipleCandidates); + if (Result.isInvalid()) + return true; + // Record usage of conversion in an implicit cast. + From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(), + CK_UserDefinedConversion, Result.get(), + nullptr, Result.get()->getValueKind()); + } + return false; +} + +static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From, + Sema::ContextualImplicitConverter &Converter, + QualType T, bool HadMultipleCandidates, + DeclAccessPair &Found) { + CXXConversionDecl *Conversion = + cast<CXXConversionDecl>(Found->getUnderlyingDecl()); + SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found); + + QualType ToType = Conversion->getConversionType().getNonReferenceType(); + if (!Converter.SuppressConversion) { + if (SemaRef.isSFINAEContext()) + return true; + + Converter.diagnoseConversion(SemaRef, Loc, T, ToType) + << From->getSourceRange(); + } + + ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion, + HadMultipleCandidates); + if (Result.isInvalid()) + return true; + // Record usage of conversion in an implicit cast. + From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(), + CK_UserDefinedConversion, Result.get(), + nullptr, Result.get()->getValueKind()); + return false; +} + +static ExprResult finishContextualImplicitConversion( + Sema &SemaRef, SourceLocation Loc, Expr *From, + Sema::ContextualImplicitConverter &Converter) { + if (!Converter.match(From->getType()) && !Converter.Suppress) + Converter.diagnoseNoMatch(SemaRef, Loc, From->getType()) + << From->getSourceRange(); + + return SemaRef.DefaultLvalueConversion(From); +} + +static void +collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType, + UnresolvedSetImpl &ViableConversions, + OverloadCandidateSet &CandidateSet) { + for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { + DeclAccessPair FoundDecl = ViableConversions[I]; + NamedDecl *D = FoundDecl.getDecl(); + CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + + CXXConversionDecl *Conv; + FunctionTemplateDecl *ConvTemplate; + if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) + Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); + else + Conv = cast<CXXConversionDecl>(D); + + if (ConvTemplate) + SemaRef.AddTemplateConversionCandidate( + ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet, + /*AllowObjCConversionOnExplicit=*/false); + else + SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, + ToType, CandidateSet, + /*AllowObjCConversionOnExplicit=*/false); + } +} + +/// Attempt to convert the given expression to a type which is accepted +/// by the given converter. +/// +/// This routine will attempt to convert an expression of class type to a +/// type accepted by the specified converter. In C++11 and before, the class +/// must have a single non-explicit conversion function converting to a matching +/// type. In C++1y, there can be multiple such conversion functions, but only +/// one target type. +/// +/// \param Loc The source location of the construct that requires the +/// conversion. +/// +/// \param From The expression we're converting from. +/// +/// \param Converter Used to control and diagnose the conversion process. +/// +/// \returns The expression, converted to an integral or enumeration type if +/// successful. +ExprResult Sema::PerformContextualImplicitConversion( + SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) { + // We can't perform any more checking for type-dependent expressions. + if (From->isTypeDependent()) + return From; + + // Process placeholders immediately. + if (From->hasPlaceholderType()) { + ExprResult result = CheckPlaceholderExpr(From); + if (result.isInvalid()) + return result; + From = result.get(); + } + + // If the expression already has a matching type, we're golden. + QualType T = From->getType(); + if (Converter.match(T)) + return DefaultLvalueConversion(From); + + // FIXME: Check for missing '()' if T is a function type? + + // We can only perform contextual implicit conversions on objects of class + // type. + const RecordType *RecordTy = T->getAs<RecordType>(); + if (!RecordTy || !getLangOpts().CPlusPlus) { + if (!Converter.Suppress) + Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange(); + return From; + } + + // We must have a complete class type. + struct TypeDiagnoserPartialDiag : TypeDiagnoser { + ContextualImplicitConverter &Converter; + Expr *From; + + TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From) + : Converter(Converter), From(From) {} + + void diagnose(Sema &S, SourceLocation Loc, QualType T) override { + Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange(); + } + } IncompleteDiagnoser(Converter, From); + + if (Converter.Suppress ? !isCompleteType(Loc, T) + : RequireCompleteType(Loc, T, IncompleteDiagnoser)) + return From; + + // Look for a conversion to an integral or enumeration type. + UnresolvedSet<4> + ViableConversions; // These are *potentially* viable in C++1y. + UnresolvedSet<4> ExplicitConversions; + const auto &Conversions = + cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions(); + + bool HadMultipleCandidates = + (std::distance(Conversions.begin(), Conversions.end()) > 1); + + // To check that there is only one target type, in C++1y: + QualType ToType; + bool HasUniqueTargetType = true; + + // Collect explicit or viable (potentially in C++1y) conversions. + for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { + NamedDecl *D = (*I)->getUnderlyingDecl(); + CXXConversionDecl *Conversion; + FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D); + if (ConvTemplate) { + if (getLangOpts().CPlusPlus14) + Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); + else + continue; // C++11 does not consider conversion operator templates(?). + } else + Conversion = cast<CXXConversionDecl>(D); + + assert((!ConvTemplate || getLangOpts().CPlusPlus14) && + "Conversion operator templates are considered potentially " + "viable in C++1y"); + + QualType CurToType = Conversion->getConversionType().getNonReferenceType(); + if (Converter.match(CurToType) || ConvTemplate) { + + if (Conversion->isExplicit()) { + // FIXME: For C++1y, do we need this restriction? + // cf. diagnoseNoViableConversion() + if (!ConvTemplate) + ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); + } else { + if (!ConvTemplate && getLangOpts().CPlusPlus14) { + if (ToType.isNull()) + ToType = CurToType.getUnqualifiedType(); + else if (HasUniqueTargetType && + (CurToType.getUnqualifiedType() != ToType)) + HasUniqueTargetType = false; + } + ViableConversions.addDecl(I.getDecl(), I.getAccess()); + } + } + } + + if (getLangOpts().CPlusPlus14) { + // C++1y [conv]p6: + // ... An expression e of class type E appearing in such a context + // is said to be contextually implicitly converted to a specified + // type T and is well-formed if and only if e can be implicitly + // converted to a type T that is determined as follows: E is searched + // for conversion functions whose return type is cv T or reference to + // cv T such that T is allowed by the context. There shall be + // exactly one such T. + + // If no unique T is found: + if (ToType.isNull()) { + if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, + HadMultipleCandidates, + ExplicitConversions)) + return ExprError(); + return finishContextualImplicitConversion(*this, Loc, From, Converter); + } + + // If more than one unique Ts are found: + if (!HasUniqueTargetType) + return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, + ViableConversions); + + // If one unique T is found: + // First, build a candidate set from the previously recorded + // potentially viable conversions. + OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal); + collectViableConversionCandidates(*this, From, ToType, ViableConversions, + CandidateSet); + + // Then, perform overload resolution over the candidate set. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, Loc, Best)) { + case OR_Success: { + // Apply this conversion. + DeclAccessPair Found = + DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess()); + if (recordConversion(*this, Loc, From, Converter, T, + HadMultipleCandidates, Found)) + return ExprError(); + break; + } + case OR_Ambiguous: + return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, + ViableConversions); + case OR_No_Viable_Function: + if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, + HadMultipleCandidates, + ExplicitConversions)) + return ExprError(); + LLVM_FALLTHROUGH; + case OR_Deleted: + // We'll complain below about a non-integral condition type. + break; + } + } else { + switch (ViableConversions.size()) { + case 0: { + if (diagnoseNoViableConversion(*this, Loc, From, Converter, T, + HadMultipleCandidates, + ExplicitConversions)) + return ExprError(); + + // We'll complain below about a non-integral condition type. + break; + } + case 1: { + // Apply this conversion. + DeclAccessPair Found = ViableConversions[0]; + if (recordConversion(*this, Loc, From, Converter, T, + HadMultipleCandidates, Found)) + return ExprError(); + break; + } + default: + return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T, + ViableConversions); + } + } + + return finishContextualImplicitConversion(*this, Loc, From, Converter); +} + +/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is +/// an acceptable non-member overloaded operator for a call whose +/// arguments have types T1 (and, if non-empty, T2). This routine +/// implements the check in C++ [over.match.oper]p3b2 concerning +/// enumeration types. +static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context, + FunctionDecl *Fn, + ArrayRef<Expr *> Args) { + QualType T1 = Args[0]->getType(); + QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType(); + + if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType())) + return true; + + if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType())) + return true; + + const FunctionProtoType *Proto = Fn->getType()->getAs<FunctionProtoType>(); + if (Proto->getNumParams() < 1) + return false; + + if (T1->isEnumeralType()) { + QualType ArgType = Proto->getParamType(0).getNonReferenceType(); + if (Context.hasSameUnqualifiedType(T1, ArgType)) + return true; + } + + if (Proto->getNumParams() < 2) + return false; + + if (!T2.isNull() && T2->isEnumeralType()) { + QualType ArgType = Proto->getParamType(1).getNonReferenceType(); + if (Context.hasSameUnqualifiedType(T2, ArgType)) + return true; + } + + return false; +} + +/// 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. +/// +/// \param PartialOverloading true if we are performing "partial" overloading +/// based on an incomplete set of function arguments. This feature is used by +/// code completion. +void Sema::AddOverloadCandidate(FunctionDecl *Function, + DeclAccessPair FoundDecl, ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, + bool SuppressUserConversions, + bool PartialOverloading, bool AllowExplicit, + ADLCallKind IsADLCandidate, + ConversionSequenceList EarlyConversions) { + const FunctionProtoType *Proto + = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); + assert(Proto && "Functions without a prototype cannot be overloaded"); + 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 an empty type for the implied + // object argument (C++ [over.call.func]p3), and the acting context + // is irrelevant. + AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(), + Expr::Classification::makeSimpleLValue(), Args, + CandidateSet, SuppressUserConversions, + PartialOverloading, EarlyConversions); + return; + } + // We treat a constructor like a non-member function, since its object + // argument doesn't participate in overload resolution. + } + + if (!CandidateSet.isNewCandidate(Function)) + return; + + // C++ [over.match.oper]p3: + // if no operand has a class type, only those non-member functions in the + // lookup set that have a first parameter of type T1 or "reference to + // (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there + // is a right operand) a second parameter of type T2 or "reference to + // (possibly cv-qualified) T2", when T2 is an enumeration type, are + // candidate functions. + if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator && + !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args)) + return; + + // C++11 [class.copy]p11: [DR1402] + // A defaulted move constructor that is defined as deleted is ignored by + // overload resolution. + CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function); + if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() && + Constructor->isMoveConstructor()) + return; + + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + // Add this candidate + OverloadCandidate &Candidate = + CandidateSet.addCandidate(Args.size(), EarlyConversions); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = Function; + Candidate.Viable = true; + Candidate.IsSurrogate = false; + Candidate.IsADLCandidate = IsADLCandidate; + Candidate.IgnoreObjectArgument = false; + Candidate.ExplicitCallArguments = Args.size(); + + if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() && + !Function->getAttr<TargetAttr>()->isDefaultVersion()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_non_default_multiversion_function; + return; + } + + if (Constructor) { + // C++ [class.copy]p3: + // A member function template is never instantiated to perform the copy + // of a class object to an object of its class type. + QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); + if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() && + (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || + IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(), + ClassType))) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_illegal_constructor; + return; + } + + // C++ [over.match.funcs]p8: (proposed DR resolution) + // A constructor inherited from class type C that has a first parameter + // of type "reference to P" (including such a constructor instantiated + // from a template) is excluded from the set of candidate functions when + // constructing an object of type cv D if the argument list has exactly + // one argument and D is reference-related to P and P is reference-related + // to C. + auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl()); + if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 && + Constructor->getParamDecl(0)->getType()->isReferenceType()) { + QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType(); + QualType C = Context.getRecordType(Constructor->getParent()); + QualType D = Context.getRecordType(Shadow->getParent()); + SourceLocation Loc = Args.front()->getExprLoc(); + if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) && + (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_inhctor_slice; + return; + } + } + } + + unsigned NumParams = Proto->getNumParams(); + + // (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 (TooManyArguments(NumParams, Args.size(), PartialOverloading) && + !Proto->isVariadic()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_many_arguments; + 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 (Args.size() < MinRequiredArgs && !PartialOverloading) { + // Not enough arguments. + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_few_arguments; + return; + } + + // (CUDA B.1): Check for invalid calls between targets. + if (getLangOpts().CUDA) + if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext)) + // Skip the check for callers that are implicit members, because in this + // case we may not yet know what the member's target is; the target is + // inferred for the member automatically, based on the bases and fields of + // the class. + if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_target; + return; + } + + // Determine the implicit conversion sequences for each of the + // arguments. + for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) { + if (Candidate.Conversions[ArgIdx].isInitialized()) { + // We already formed a conversion sequence for this parameter during + // template argument deduction. + } else if (ArgIdx < NumParams) { + // (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->getParamType(ArgIdx); + Candidate.Conversions[ArgIdx] + = TryCopyInitialization(*this, Args[ArgIdx], ParamType, + SuppressUserConversions, + /*InOverloadResolution=*/true, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount, + AllowExplicit); + if (Candidate.Conversions[ArgIdx].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + return; + } + } 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].setEllipsis(); + } + } + + if (EnableIfAttr *FailedAttr = CheckEnableIf(Function, Args)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_enable_if; + Candidate.DeductionFailure.Data = FailedAttr; + return; + } + + if (LangOpts.OpenCL && isOpenCLDisabledDecl(Function)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_ext_disabled; + return; + } +} + +ObjCMethodDecl * +Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance, + SmallVectorImpl<ObjCMethodDecl *> &Methods) { + if (Methods.size() <= 1) + return nullptr; + + for (unsigned b = 0, e = Methods.size(); b < e; b++) { + bool Match = true; + ObjCMethodDecl *Method = Methods[b]; + unsigned NumNamedArgs = Sel.getNumArgs(); + // Method might have more arguments than selector indicates. This is due + // to addition of c-style arguments in method. + if (Method->param_size() > NumNamedArgs) + NumNamedArgs = Method->param_size(); + if (Args.size() < NumNamedArgs) + continue; + + for (unsigned i = 0; i < NumNamedArgs; i++) { + // We can't do any type-checking on a type-dependent argument. + if (Args[i]->isTypeDependent()) { + Match = false; + break; + } + + ParmVarDecl *param = Method->parameters()[i]; + Expr *argExpr = Args[i]; + assert(argExpr && "SelectBestMethod(): missing expression"); + + // Strip the unbridged-cast placeholder expression off unless it's + // a consumed argument. + if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) && + !param->hasAttr<CFConsumedAttr>()) + argExpr = stripARCUnbridgedCast(argExpr); + + // If the parameter is __unknown_anytype, move on to the next method. + if (param->getType() == Context.UnknownAnyTy) { + Match = false; + break; + } + + ImplicitConversionSequence ConversionState + = TryCopyInitialization(*this, argExpr, param->getType(), + /*SuppressUserConversions*/false, + /*InOverloadResolution=*/true, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount, + /*AllowExplicit*/false); + // This function looks for a reasonably-exact match, so we consider + // incompatible pointer conversions to be a failure here. + if (ConversionState.isBad() || + (ConversionState.isStandard() && + ConversionState.Standard.Second == + ICK_Incompatible_Pointer_Conversion)) { + Match = false; + break; + } + } + // Promote additional arguments to variadic methods. + if (Match && Method->isVariadic()) { + for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) { + if (Args[i]->isTypeDependent()) { + Match = false; + break; + } + ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod, + nullptr); + if (Arg.isInvalid()) { + Match = false; + break; + } + } + } else { + // Check for extra arguments to non-variadic methods. + if (Args.size() != NumNamedArgs) + Match = false; + else if (Match && NumNamedArgs == 0 && Methods.size() > 1) { + // Special case when selectors have no argument. In this case, select + // one with the most general result type of 'id'. + for (unsigned b = 0, e = Methods.size(); b < e; b++) { + QualType ReturnT = Methods[b]->getReturnType(); + if (ReturnT->isObjCIdType()) + return Methods[b]; + } + } + } + + if (Match) + return Method; + } + return nullptr; +} + +static bool +convertArgsForAvailabilityChecks(Sema &S, FunctionDecl *Function, Expr *ThisArg, + ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap, + bool MissingImplicitThis, Expr *&ConvertedThis, + SmallVectorImpl<Expr *> &ConvertedArgs) { + if (ThisArg) { + CXXMethodDecl *Method = cast<CXXMethodDecl>(Function); + assert(!isa<CXXConstructorDecl>(Method) && + "Shouldn't have `this` for ctors!"); + assert(!Method->isStatic() && "Shouldn't have `this` for static methods!"); + ExprResult R = S.PerformObjectArgumentInitialization( + ThisArg, /*Qualifier=*/nullptr, Method, Method); + if (R.isInvalid()) + return false; + ConvertedThis = R.get(); + } else { + if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) { + (void)MD; + assert((MissingImplicitThis || MD->isStatic() || + isa<CXXConstructorDecl>(MD)) && + "Expected `this` for non-ctor instance methods"); + } + ConvertedThis = nullptr; + } + + // Ignore any variadic arguments. Converting them is pointless, since the + // user can't refer to them in the function condition. + unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size()); + + // Convert the arguments. + for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) { + ExprResult R; + R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter( + S.Context, Function->getParamDecl(I)), + SourceLocation(), Args[I]); + + if (R.isInvalid()) + return false; + + ConvertedArgs.push_back(R.get()); + } + + if (Trap.hasErrorOccurred()) + return false; + + // Push default arguments if needed. + if (!Function->isVariadic() && Args.size() < Function->getNumParams()) { + for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) { + ParmVarDecl *P = Function->getParamDecl(i); + Expr *DefArg = P->hasUninstantiatedDefaultArg() + ? P->getUninstantiatedDefaultArg() + : P->getDefaultArg(); + // This can only happen in code completion, i.e. when PartialOverloading + // is true. + if (!DefArg) + return false; + ExprResult R = + S.PerformCopyInitialization(InitializedEntity::InitializeParameter( + S.Context, Function->getParamDecl(i)), + SourceLocation(), DefArg); + if (R.isInvalid()) + return false; + ConvertedArgs.push_back(R.get()); + } + + if (Trap.hasErrorOccurred()) + return false; + } + return true; +} + +EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function, ArrayRef<Expr *> Args, + bool MissingImplicitThis) { + auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>(); + if (EnableIfAttrs.begin() == EnableIfAttrs.end()) + return nullptr; + + SFINAETrap Trap(*this); + SmallVector<Expr *, 16> ConvertedArgs; + // FIXME: We should look into making enable_if late-parsed. + Expr *DiscardedThis; + if (!convertArgsForAvailabilityChecks( + *this, Function, /*ThisArg=*/nullptr, Args, Trap, + /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs)) + return *EnableIfAttrs.begin(); + + for (auto *EIA : EnableIfAttrs) { + APValue Result; + // FIXME: This doesn't consider value-dependent cases, because doing so is + // very difficult. Ideally, we should handle them more gracefully. + if (!EIA->getCond()->EvaluateWithSubstitution( + Result, Context, Function, llvm::makeArrayRef(ConvertedArgs))) + return EIA; + + if (!Result.isInt() || !Result.getInt().getBoolValue()) + return EIA; + } + return nullptr; +} + +template <typename CheckFn> +static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND, + bool ArgDependent, SourceLocation Loc, + CheckFn &&IsSuccessful) { + SmallVector<const DiagnoseIfAttr *, 8> Attrs; + for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) { + if (ArgDependent == DIA->getArgDependent()) + Attrs.push_back(DIA); + } + + // Common case: No diagnose_if attributes, so we can quit early. + if (Attrs.empty()) + return false; + + auto WarningBegin = std::stable_partition( + Attrs.begin(), Attrs.end(), + [](const DiagnoseIfAttr *DIA) { return DIA->isError(); }); + + // Note that diagnose_if attributes are late-parsed, so they appear in the + // correct order (unlike enable_if attributes). + auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin), + IsSuccessful); + if (ErrAttr != WarningBegin) { + const DiagnoseIfAttr *DIA = *ErrAttr; + S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage(); + S.Diag(DIA->getLocation(), diag::note_from_diagnose_if) + << DIA->getParent() << DIA->getCond()->getSourceRange(); + return true; + } + + for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end())) + if (IsSuccessful(DIA)) { + S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage(); + S.Diag(DIA->getLocation(), diag::note_from_diagnose_if) + << DIA->getParent() << DIA->getCond()->getSourceRange(); + } + + return false; +} + +bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function, + const Expr *ThisArg, + ArrayRef<const Expr *> Args, + SourceLocation Loc) { + return diagnoseDiagnoseIfAttrsWith( + *this, Function, /*ArgDependent=*/true, Loc, + [&](const DiagnoseIfAttr *DIA) { + APValue Result; + // It's sane to use the same Args for any redecl of this function, since + // EvaluateWithSubstitution only cares about the position of each + // argument in the arg list, not the ParmVarDecl* it maps to. + if (!DIA->getCond()->EvaluateWithSubstitution( + Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg)) + return false; + return Result.isInt() && Result.getInt().getBoolValue(); + }); +} + +bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND, + SourceLocation Loc) { + return diagnoseDiagnoseIfAttrsWith( + *this, ND, /*ArgDependent=*/false, Loc, + [&](const DiagnoseIfAttr *DIA) { + bool Result; + return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) && + Result; + }); +} + +/// Add all of the function declarations in the given function set to +/// the overload candidate set. +void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, + TemplateArgumentListInfo *ExplicitTemplateArgs, + bool SuppressUserConversions, + bool PartialOverloading, + bool FirstArgumentIsBase) { + for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { + NamedDecl *D = F.getDecl()->getUnderlyingDecl(); + ArrayRef<Expr *> FunctionArgs = Args; + + FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D); + FunctionDecl *FD = + FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D); + + if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) { + QualType ObjectType; + Expr::Classification ObjectClassification; + if (Args.size() > 0) { + if (Expr *E = Args[0]) { + // Use the explicit base to restrict the lookup: + ObjectType = E->getType(); + // Pointers in the object arguments are implicitly dereferenced, so we + // always classify them as l-values. + if (!ObjectType.isNull() && ObjectType->isPointerType()) + ObjectClassification = Expr::Classification::makeSimpleLValue(); + else + ObjectClassification = E->Classify(Context); + } // .. else there is an implicit base. + FunctionArgs = Args.slice(1); + } + if (FunTmpl) { + AddMethodTemplateCandidate( + FunTmpl, F.getPair(), + cast<CXXRecordDecl>(FunTmpl->getDeclContext()), + ExplicitTemplateArgs, ObjectType, ObjectClassification, + FunctionArgs, CandidateSet, SuppressUserConversions, + PartialOverloading); + } else { + AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), + cast<CXXMethodDecl>(FD)->getParent(), ObjectType, + ObjectClassification, FunctionArgs, CandidateSet, + SuppressUserConversions, PartialOverloading); + } + } else { + // This branch handles both standalone functions and static methods. + + // Slice the first argument (which is the base) when we access + // static method as non-static. + if (Args.size() > 0 && + (!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) && + !isa<CXXConstructorDecl>(FD)))) { + assert(cast<CXXMethodDecl>(FD)->isStatic()); + FunctionArgs = Args.slice(1); + } + if (FunTmpl) { + AddTemplateOverloadCandidate( + FunTmpl, F.getPair(), ExplicitTemplateArgs, FunctionArgs, + CandidateSet, SuppressUserConversions, PartialOverloading); + } else { + AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet, + SuppressUserConversions, PartialOverloading); + } + } + } +} + +/// AddMethodCandidate - Adds a named decl (which is some kind of +/// method) as a method candidate to the given overload set. +void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, + QualType ObjectType, + Expr::Classification ObjectClassification, + ArrayRef<Expr *> Args, + OverloadCandidateSet& CandidateSet, + bool SuppressUserConversions) { + NamedDecl *Decl = FoundDecl.getDecl(); + CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); + + if (isa<UsingShadowDecl>(Decl)) + Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); + + if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { + assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && + "Expected a member function template"); + AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, + /*ExplicitArgs*/ nullptr, ObjectType, + ObjectClassification, Args, CandidateSet, + SuppressUserConversions); + } else { + AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, + ObjectType, ObjectClassification, Args, 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. +void +Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, + CXXRecordDecl *ActingContext, QualType ObjectType, + Expr::Classification ObjectClassification, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, + bool SuppressUserConversions, + bool PartialOverloading, + ConversionSequenceList EarlyConversions) { + const FunctionProtoType *Proto + = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); + assert(Proto && "Methods without a prototype cannot be overloaded"); + assert(!isa<CXXConstructorDecl>(Method) && + "Use AddOverloadCandidate for constructors"); + + if (!CandidateSet.isNewCandidate(Method)) + return; + + // C++11 [class.copy]p23: [DR1402] + // A defaulted move assignment operator that is defined as deleted is + // ignored by overload resolution. + if (Method->isDefaulted() && Method->isDeleted() && + Method->isMoveAssignmentOperator()) + return; + + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + // Add this candidate + OverloadCandidate &Candidate = + CandidateSet.addCandidate(Args.size() + 1, EarlyConversions); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = Method; + Candidate.IsSurrogate = false; + Candidate.IgnoreObjectArgument = false; + Candidate.ExplicitCallArguments = Args.size(); + + unsigned NumParams = Proto->getNumParams(); + + // (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 (TooManyArguments(NumParams, Args.size(), PartialOverloading) && + !Proto->isVariadic()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_many_arguments; + 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 (Args.size() < MinRequiredArgs && !PartialOverloading) { + // Not enough arguments. + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_few_arguments; + return; + } + + Candidate.Viable = true; + + if (Method->isStatic() || ObjectType.isNull()) + // The implicit object argument is ignored. + Candidate.IgnoreObjectArgument = true; + else { + // Determine the implicit conversion sequence for the object + // parameter. + Candidate.Conversions[0] = TryObjectArgumentInitialization( + *this, CandidateSet.getLocation(), ObjectType, ObjectClassification, + Method, ActingContext); + if (Candidate.Conversions[0].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + return; + } + } + + // (CUDA B.1): Check for invalid calls between targets. + if (getLangOpts().CUDA) + if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext)) + if (!IsAllowedCUDACall(Caller, Method)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_target; + return; + } + + // Determine the implicit conversion sequences for each of the + // arguments. + for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) { + if (Candidate.Conversions[ArgIdx + 1].isInitialized()) { + // We already formed a conversion sequence for this parameter during + // template argument deduction. + } else if (ArgIdx < NumParams) { + // (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->getParamType(ArgIdx); + Candidate.Conversions[ArgIdx + 1] + = TryCopyInitialization(*this, Args[ArgIdx], ParamType, + SuppressUserConversions, + /*InOverloadResolution=*/true, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount); + if (Candidate.Conversions[ArgIdx + 1].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + return; + } + } 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].setEllipsis(); + } + } + + if (EnableIfAttr *FailedAttr = CheckEnableIf(Method, Args, true)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_enable_if; + Candidate.DeductionFailure.Data = FailedAttr; + return; + } + + if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() && + !Method->getAttr<TargetAttr>()->isDefaultVersion()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_non_default_multiversion_function; + } +} + +/// 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, + DeclAccessPair FoundDecl, + CXXRecordDecl *ActingContext, + TemplateArgumentListInfo *ExplicitTemplateArgs, + QualType ObjectType, + Expr::Classification ObjectClassification, + ArrayRef<Expr *> Args, + OverloadCandidateSet& CandidateSet, + bool SuppressUserConversions, + bool PartialOverloading) { + if (!CandidateSet.isNewCandidate(MethodTmpl)) + return; + + // 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(CandidateSet.getLocation()); + FunctionDecl *Specialization = nullptr; + ConversionSequenceList Conversions; + if (TemplateDeductionResult Result = DeduceTemplateArguments( + MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info, + PartialOverloading, [&](ArrayRef<QualType> ParamTypes) { + return CheckNonDependentConversions( + MethodTmpl, ParamTypes, Args, CandidateSet, Conversions, + SuppressUserConversions, ActingContext, ObjectType, + ObjectClassification); + })) { + OverloadCandidate &Candidate = + CandidateSet.addCandidate(Conversions.size(), Conversions); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = MethodTmpl->getTemplatedDecl(); + Candidate.Viable = false; + Candidate.IsSurrogate = false; + Candidate.IgnoreObjectArgument = + cast<CXXMethodDecl>(Candidate.Function)->isStatic() || + ObjectType.isNull(); + Candidate.ExplicitCallArguments = Args.size(); + if (Result == TDK_NonDependentConversionFailure) + Candidate.FailureKind = ovl_fail_bad_conversion; + else { + Candidate.FailureKind = ovl_fail_bad_deduction; + Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, + Info); + } + 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), FoundDecl, + ActingContext, ObjectType, ObjectClassification, Args, + CandidateSet, SuppressUserConversions, PartialOverloading, + Conversions); +} + +/// 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, DeclAccessPair FoundDecl, + TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, bool SuppressUserConversions, + bool PartialOverloading, ADLCallKind IsADLCandidate) { + if (!CandidateSet.isNewCandidate(FunctionTemplate)) + return; + + // 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(CandidateSet.getLocation()); + FunctionDecl *Specialization = nullptr; + ConversionSequenceList Conversions; + if (TemplateDeductionResult Result = DeduceTemplateArguments( + FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info, + PartialOverloading, [&](ArrayRef<QualType> ParamTypes) { + return CheckNonDependentConversions(FunctionTemplate, ParamTypes, + Args, CandidateSet, Conversions, + SuppressUserConversions); + })) { + OverloadCandidate &Candidate = + CandidateSet.addCandidate(Conversions.size(), Conversions); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = FunctionTemplate->getTemplatedDecl(); + Candidate.Viable = false; + Candidate.IsSurrogate = false; + Candidate.IsADLCandidate = IsADLCandidate; + // Ignore the object argument if there is one, since we don't have an object + // type. + Candidate.IgnoreObjectArgument = + isa<CXXMethodDecl>(Candidate.Function) && + !isa<CXXConstructorDecl>(Candidate.Function); + Candidate.ExplicitCallArguments = Args.size(); + if (Result == TDK_NonDependentConversionFailure) + Candidate.FailureKind = ovl_fail_bad_conversion; + else { + Candidate.FailureKind = ovl_fail_bad_deduction; + Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, + Info); + } + return; + } + + // Add the function template specialization produced by template argument + // deduction as a candidate. + assert(Specialization && "Missing function template specialization?"); + AddOverloadCandidate(Specialization, FoundDecl, Args, CandidateSet, + SuppressUserConversions, PartialOverloading, + /*AllowExplicit*/ false, IsADLCandidate, Conversions); +} + +/// Check that implicit conversion sequences can be formed for each argument +/// whose corresponding parameter has a non-dependent type, per DR1391's +/// [temp.deduct.call]p10. +bool Sema::CheckNonDependentConversions( + FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes, + ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet, + ConversionSequenceList &Conversions, bool SuppressUserConversions, + CXXRecordDecl *ActingContext, QualType ObjectType, + Expr::Classification ObjectClassification) { + // FIXME: The cases in which we allow explicit conversions for constructor + // arguments never consider calling a constructor template. It's not clear + // that is correct. + const bool AllowExplicit = false; + + auto *FD = FunctionTemplate->getTemplatedDecl(); + auto *Method = dyn_cast<CXXMethodDecl>(FD); + bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method); + unsigned ThisConversions = HasThisConversion ? 1 : 0; + + Conversions = + CandidateSet.allocateConversionSequences(ThisConversions + Args.size()); + + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + // For a method call, check the 'this' conversion here too. DR1391 doesn't + // require that, but this check should never result in a hard error, and + // overload resolution is permitted to sidestep instantiations. + if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() && + !ObjectType.isNull()) { + Conversions[0] = TryObjectArgumentInitialization( + *this, CandidateSet.getLocation(), ObjectType, ObjectClassification, + Method, ActingContext); + if (Conversions[0].isBad()) + return true; + } + + for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N; + ++I) { + QualType ParamType = ParamTypes[I]; + if (!ParamType->isDependentType()) { + Conversions[ThisConversions + I] + = TryCopyInitialization(*this, Args[I], ParamType, + SuppressUserConversions, + /*InOverloadResolution=*/true, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount, + AllowExplicit); + if (Conversions[ThisConversions + I].isBad()) + return true; + } + } + + return false; +} + +/// Determine whether this is an allowable conversion from the result +/// of an explicit conversion operator to the expected type, per C++ +/// [over.match.conv]p1 and [over.match.ref]p1. +/// +/// \param ConvType The return type of the conversion function. +/// +/// \param ToType The type we are converting to. +/// +/// \param AllowObjCPointerConversion Allow a conversion from one +/// Objective-C pointer to another. +/// +/// \returns true if the conversion is allowable, false otherwise. +static bool isAllowableExplicitConversion(Sema &S, + QualType ConvType, QualType ToType, + bool AllowObjCPointerConversion) { + QualType ToNonRefType = ToType.getNonReferenceType(); + + // Easy case: the types are the same. + if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType)) + return true; + + // Allow qualification conversions. + bool ObjCLifetimeConversion; + if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false, + ObjCLifetimeConversion)) + return true; + + // If we're not allowed to consider Objective-C pointer conversions, + // we're done. + if (!AllowObjCPointerConversion) + return false; + + // Is this an Objective-C pointer conversion? + bool IncompatibleObjC = false; + QualType ConvertedType; + return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType, + IncompatibleObjC); +} + +/// 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, + DeclAccessPair FoundDecl, + CXXRecordDecl *ActingContext, + Expr *From, QualType ToType, + OverloadCandidateSet& CandidateSet, + bool AllowObjCConversionOnExplicit, + bool AllowResultConversion) { + assert(!Conversion->getDescribedFunctionTemplate() && + "Conversion function templates use AddTemplateConversionCandidate"); + QualType ConvType = Conversion->getConversionType().getNonReferenceType(); + if (!CandidateSet.isNewCandidate(Conversion)) + return; + + // If the conversion function has an undeduced return type, trigger its + // deduction now. + if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) { + if (DeduceReturnType(Conversion, From->getExprLoc())) + return; + ConvType = Conversion->getConversionType().getNonReferenceType(); + } + + // If we don't allow any conversion of the result type, ignore conversion + // functions that don't convert to exactly (possibly cv-qualified) T. + if (!AllowResultConversion && + !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType)) + return; + + // Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion + // operator is only a candidate if its return type is the target type or + // can be converted to the target type with a qualification conversion. + if (Conversion->isExplicit() && + !isAllowableExplicitConversion(*this, ConvType, ToType, + AllowObjCConversionOnExplicit)) + return; + + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + // Add this candidate + OverloadCandidate &Candidate = CandidateSet.addCandidate(1); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = Conversion; + Candidate.IsSurrogate = false; + Candidate.IgnoreObjectArgument = false; + Candidate.FinalConversion.setAsIdentityConversion(); + Candidate.FinalConversion.setFromType(ConvType); + Candidate.FinalConversion.setAllToTypes(ToType); + Candidate.Viable = true; + Candidate.ExplicitCallArguments = 1; + + // C++ [over.match.funcs]p4: + // For conversion functions, the function is considered to be a member of + // the class of the implicit implied object argument for the purpose of + // defining the type of the implicit object parameter. + // + // Determine the implicit conversion sequence for the implicit + // object parameter. + QualType ImplicitParamType = From->getType(); + if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>()) + ImplicitParamType = FromPtrType->getPointeeType(); + CXXRecordDecl *ConversionContext + = cast<CXXRecordDecl>(ImplicitParamType->getAs<RecordType>()->getDecl()); + + Candidate.Conversions[0] = TryObjectArgumentInitialization( + *this, CandidateSet.getLocation(), From->getType(), + From->Classify(Context), Conversion, ConversionContext); + + if (Candidate.Conversions[0].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + return; + } + + // We won't go through a user-defined type conversion function to convert a + // derived to base as such conversions are given Conversion Rank. They only + // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] + QualType FromCanon + = Context.getCanonicalType(From->getType().getUnqualifiedType()); + QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); + if (FromCanon == ToCanon || + IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_trivial_conversion; + 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(Context, Conversion, false, Conversion->getType(), + VK_LValue, From->getBeginLoc()); + ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack, + Context.getPointerType(Conversion->getType()), + CK_FunctionToPointerDecay, + &ConversionRef, VK_RValue); + + QualType ConversionType = Conversion->getConversionType(); + if (!isCompleteType(From->getBeginLoc(), ConversionType)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_final_conversion; + return; + } + + ExprValueKind VK = Expr::getValueKindForType(ConversionType); + + // 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). + QualType CallResultType = ConversionType.getNonLValueExprType(Context); + + llvm::AlignedCharArray<alignof(CallExpr), sizeof(CallExpr) + sizeof(Stmt *)> + Buffer; + CallExpr *TheTemporaryCall = CallExpr::CreateTemporary( + Buffer.buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc()); + + ImplicitConversionSequence ICS = + TryCopyInitialization(*this, TheTemporaryCall, ToType, + /*SuppressUserConversions=*/true, + /*InOverloadResolution=*/false, + /*AllowObjCWritebackConversion=*/false); + + switch (ICS.getKind()) { + case ImplicitConversionSequence::StandardConversion: + Candidate.FinalConversion = ICS.Standard; + + // C++ [over.ics.user]p3: + // If the user-defined conversion is specified by a specialization of a + // conversion function template, the second standard conversion sequence + // shall have exact match rank. + if (Conversion->getPrimaryTemplate() && + GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_final_conversion_not_exact; + return; + } + + // C++0x [dcl.init.ref]p5: + // In the second case, if the reference is an rvalue reference and + // the second standard conversion sequence of the user-defined + // conversion sequence includes an lvalue-to-rvalue conversion, the + // program is ill-formed. + if (ToType->isRValueReferenceType() && + ICS.Standard.First == ICK_Lvalue_To_Rvalue) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_final_conversion; + return; + } + break; + + case ImplicitConversionSequence::BadConversion: + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_final_conversion; + return; + + default: + llvm_unreachable( + "Can only end up with a standard conversion sequence or failure"); + } + + if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, None)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_enable_if; + Candidate.DeductionFailure.Data = FailedAttr; + return; + } + + if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() && + !Conversion->getAttr<TargetAttr>()->isDefaultVersion()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_non_default_multiversion_function; + } +} + +/// 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, + DeclAccessPair FoundDecl, + CXXRecordDecl *ActingDC, + Expr *From, QualType ToType, + OverloadCandidateSet &CandidateSet, + bool AllowObjCConversionOnExplicit, + bool AllowResultConversion) { + assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && + "Only conversion function templates permitted here"); + + if (!CandidateSet.isNewCandidate(FunctionTemplate)) + return; + + TemplateDeductionInfo Info(CandidateSet.getLocation()); + CXXConversionDecl *Specialization = nullptr; + if (TemplateDeductionResult Result + = DeduceTemplateArguments(FunctionTemplate, ToType, + Specialization, Info)) { + OverloadCandidate &Candidate = CandidateSet.addCandidate(); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = FunctionTemplate->getTemplatedDecl(); + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_deduction; + Candidate.IsSurrogate = false; + Candidate.IgnoreObjectArgument = false; + Candidate.ExplicitCallArguments = 1; + Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, + Info); + return; + } + + // Add the conversion function template specialization produced by + // template argument deduction as a candidate. + assert(Specialization && "Missing function template specialization?"); + AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, + CandidateSet, AllowObjCConversionOnExplicit, + AllowResultConversion); +} + +/// 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, + DeclAccessPair FoundDecl, + CXXRecordDecl *ActingContext, + const FunctionProtoType *Proto, + Expr *Object, + ArrayRef<Expr *> Args, + OverloadCandidateSet& CandidateSet) { + if (!CandidateSet.isNewCandidate(Conversion)) + return; + + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1); + Candidate.FoundDecl = FoundDecl; + Candidate.Function = nullptr; + Candidate.Surrogate = Conversion; + Candidate.Viable = true; + Candidate.IsSurrogate = true; + Candidate.IgnoreObjectArgument = false; + Candidate.ExplicitCallArguments = Args.size(); + + // Determine the implicit conversion sequence for the implicit + // object parameter. + ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization( + *this, CandidateSet.getLocation(), Object->getType(), + Object->Classify(Context), Conversion, ActingContext); + if (ObjectInit.isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + Candidate.Conversions[0] = ObjectInit; + 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].setUserDefined(); + Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; + Candidate.Conversions[0].UserDefined.EllipsisConversion = false; + Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false; + Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; + Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl; + Candidate.Conversions[0].UserDefined.After + = Candidate.Conversions[0].UserDefined.Before; + Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); + + // Find the + unsigned NumParams = Proto->getNumParams(); + + // (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 (Args.size() > NumParams && !Proto->isVariadic()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_many_arguments; + return; + } + + // Function types don't have any default arguments, so just check if + // we have enough arguments. + if (Args.size() < NumParams) { + // Not enough arguments. + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_too_few_arguments; + return; + } + + // Determine the implicit conversion sequences for each of the + // arguments. + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + if (ArgIdx < NumParams) { + // (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->getParamType(ArgIdx); + Candidate.Conversions[ArgIdx + 1] + = TryCopyInitialization(*this, Args[ArgIdx], ParamType, + /*SuppressUserConversions=*/false, + /*InOverloadResolution=*/false, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount); + if (Candidate.Conversions[ArgIdx + 1].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + return; + } + } 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].setEllipsis(); + } + } + + if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, None)) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_enable_if; + Candidate.DeductionFailure.Data = FailedAttr; + return; + } +} + +/// Add overload candidates for overloaded operators that are +/// member functions. +/// +/// Add the overloaded operator candidates that are member functions +/// for the operator Op that was used in an operator expression such +/// as "x Op y". , Args/NumArgs provides the operator arguments, and +/// CandidateSet will store the added overload candidates. (C++ +/// [over.match.oper]). +void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, + SourceLocation OpLoc, + ArrayRef<Expr *> Args, + OverloadCandidateSet& CandidateSet, + SourceRange OpRange) { + DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); + + // C++ [over.match.oper]p3: + // For a unary operator @ with an operand of a type whose + // cv-unqualified version is T1, and for a binary operator @ with + // a left operand of a type whose cv-unqualified version is T1 and + // a right operand of a type whose cv-unqualified version is T2, + // three sets of candidate functions, designated member + // candidates, non-member candidates and built-in candidates, are + // constructed as follows: + QualType T1 = Args[0]->getType(); + + // -- If T1 is a complete class type or a class currently being + // defined, the set of member candidates is the result of the + // qualified lookup of T1::operator@ (13.3.1.1.1); otherwise, + // the set of member candidates is empty. + if (const RecordType *T1Rec = T1->getAs<RecordType>()) { + // Complete the type if it can be completed. + if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined()) + return; + // If the type is neither complete nor being defined, bail out now. + if (!T1Rec->getDecl()->getDefinition()) + return; + + LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); + LookupQualifiedName(Operators, T1Rec->getDecl()); + Operators.suppressDiagnostics(); + + for (LookupResult::iterator Oper = Operators.begin(), + OperEnd = Operators.end(); + Oper != OperEnd; + ++Oper) + AddMethodCandidate(Oper.getPair(), Args[0]->getType(), + Args[0]->Classify(Context), Args.slice(1), + CandidateSet, /*SuppressUserConversions=*/false); + } +} + +/// AddBuiltinCandidate - Add a candidate for a built-in +/// operator. ResultTy and ParamTys are the result and parameter types +/// of the built-in candidate, respectively. Args and NumArgs are the +/// arguments being passed to the candidate. IsAssignmentOperator +/// should be true when this built-in candidate is an assignment +/// operator. NumContextualBoolArguments is the number of arguments +/// (at the beginning of the argument list) that will be contextually +/// converted to bool. +void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args, + OverloadCandidateSet& CandidateSet, + bool IsAssignmentOperator, + unsigned NumContextualBoolArguments) { + // Overload resolution is always an unevaluated context. + EnterExpressionEvaluationContext Unevaluated( + *this, Sema::ExpressionEvaluationContext::Unevaluated); + + // Add this candidate + OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size()); + Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none); + Candidate.Function = nullptr; + Candidate.IsSurrogate = false; + Candidate.IgnoreObjectArgument = false; + std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes); + + // Determine the implicit conversion sequences for each of the + // arguments. + Candidate.Viable = true; + Candidate.ExplicitCallArguments = Args.size(); + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + // C++ [over.match.oper]p4: + // For the built-in assignment operators, conversions of the + // left operand are restricted as follows: + // -- no temporaries are introduced to hold the left operand, and + // -- no user-defined conversions are applied to the left + // operand to achieve a type match with the left-most + // parameter of a built-in candidate. + // + // We block these conversions by turning off user-defined + // conversions, since that is the only way that initialization of + // a reference to a non-class type can occur from something that + // is not of the same type. + if (ArgIdx < NumContextualBoolArguments) { + assert(ParamTys[ArgIdx] == Context.BoolTy && + "Contextual conversion to bool requires bool type"); + Candidate.Conversions[ArgIdx] + = TryContextuallyConvertToBool(*this, Args[ArgIdx]); + } else { + Candidate.Conversions[ArgIdx] + = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], + ArgIdx == 0 && IsAssignmentOperator, + /*InOverloadResolution=*/false, + /*AllowObjCWritebackConversion=*/ + getLangOpts().ObjCAutoRefCount); + } + if (Candidate.Conversions[ArgIdx].isBad()) { + Candidate.Viable = false; + Candidate.FailureKind = ovl_fail_bad_conversion; + break; + } + } +} + +namespace { + +/// BuiltinCandidateTypeSet - A set of types that will be used for the +/// candidate operator functions for built-in operators (C++ +/// [over.built]). The types are separated into pointer types and +/// enumeration types. +class BuiltinCandidateTypeSet { + /// TypeSet - A set of types. + typedef llvm::SetVector<QualType, SmallVector<QualType, 8>, + llvm::SmallPtrSet<QualType, 8>> TypeSet; + + /// PointerTypes - The set of pointer types that will be used in the + /// built-in candidates. + TypeSet PointerTypes; + + /// MemberPointerTypes - The set of member pointer types that will be + /// used in the built-in candidates. + TypeSet MemberPointerTypes; + + /// EnumerationTypes - The set of enumeration types that will be + /// used in the built-in candidates. + TypeSet EnumerationTypes; + + /// The set of vector types that will be used in the built-in + /// candidates. + TypeSet VectorTypes; + + /// A flag indicating non-record types are viable candidates + bool HasNonRecordTypes; + + /// A flag indicating whether either arithmetic or enumeration types + /// were present in the candidate set. + bool HasArithmeticOrEnumeralTypes; + + /// A flag indicating whether the nullptr type was present in the + /// candidate set. + bool HasNullPtrType; + + /// Sema - The semantic analysis instance where we are building the + /// candidate type set. + Sema &SemaRef; + + /// Context - The AST context in which we will build the type sets. + ASTContext &Context; + + bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, + const Qualifiers &VisibleQuals); + bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); + +public: + /// iterator - Iterates through the types that are part of the set. + typedef TypeSet::iterator iterator; + + BuiltinCandidateTypeSet(Sema &SemaRef) + : HasNonRecordTypes(false), + HasArithmeticOrEnumeralTypes(false), + HasNullPtrType(false), + SemaRef(SemaRef), + Context(SemaRef.Context) { } + + void AddTypesConvertedFrom(QualType Ty, + SourceLocation Loc, + bool AllowUserConversions, + bool AllowExplicitConversions, + const Qualifiers &VisibleTypeConversionsQuals); + + /// pointer_begin - First pointer type found; + iterator pointer_begin() { return PointerTypes.begin(); } + + /// pointer_end - Past the last pointer type found; + iterator pointer_end() { return PointerTypes.end(); } + + /// member_pointer_begin - First member pointer type found; + iterator member_pointer_begin() { return MemberPointerTypes.begin(); } + + /// member_pointer_end - Past the last member pointer type found; + iterator member_pointer_end() { return MemberPointerTypes.end(); } + + /// enumeration_begin - First enumeration type found; + iterator enumeration_begin() { return EnumerationTypes.begin(); } + + /// enumeration_end - Past the last enumeration type found; + iterator enumeration_end() { return EnumerationTypes.end(); } + + iterator vector_begin() { return VectorTypes.begin(); } + iterator vector_end() { return VectorTypes.end(); } + + bool hasNonRecordTypes() { return HasNonRecordTypes; } + bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; } + bool hasNullPtrType() const { return HasNullPtrType; } +}; + +} // end anonymous namespace + +/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to +/// the set of pointer types along with any more-qualified variants of +/// that type. For example, if @p Ty is "int const *", this routine +/// will add "int const *", "int const volatile *", "int const +/// restrict *", and "int const volatile restrict *" to the set of +/// pointer types. Returns true if the add of @p Ty itself succeeded, +/// false otherwise. +/// +/// FIXME: what to do about extended qualifiers? +bool +BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, + const Qualifiers &VisibleQuals) { + + // Insert this type. + if (!PointerTypes.insert(Ty)) + return false; + + QualType PointeeTy; + const PointerType *PointerTy = Ty->getAs<PointerType>(); + bool buildObjCPtr = false; + if (!PointerTy) { + const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>(); + PointeeTy = PTy->getPointeeType(); + buildObjCPtr = true; + } else { + PointeeTy = PointerTy->getPointeeType(); + } + + // Don't add qualified variants of arrays. For one, they're not allowed + // (the qualifier would sink to the element type), and for another, the + // only overload situation where it matters is subscript or pointer +- int, + // and those shouldn't have qualifier variants anyway. + if (PointeeTy->isArrayType()) + return true; + + unsigned BaseCVR = PointeeTy.getCVRQualifiers(); + bool hasVolatile = VisibleQuals.hasVolatile(); + bool hasRestrict = VisibleQuals.hasRestrict(); + + // Iterate through all strict supersets of BaseCVR. + for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { + if ((CVR | BaseCVR) != CVR) continue; + // Skip over volatile if no volatile found anywhere in the types. + if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; + + // Skip over restrict if no restrict found anywhere in the types, or if + // the type cannot be restrict-qualified. + if ((CVR & Qualifiers::Restrict) && + (!hasRestrict || + (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType())))) + continue; + + // Build qualified pointee type. + QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); + + // Build qualified pointer type. + QualType QPointerTy; + if (!buildObjCPtr) + QPointerTy = Context.getPointerType(QPointeeTy); + else + QPointerTy = Context.getObjCObjectPointerType(QPointeeTy); + + // Insert qualified pointer type. + PointerTypes.insert(QPointerTy); + } + + return true; +} + +/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty +/// to the set of pointer types along with any more-qualified variants of +/// that type. For example, if @p Ty is "int const *", this routine +/// will add "int const *", "int const volatile *", "int const +/// restrict *", and "int const volatile restrict *" to the set of +/// pointer types. Returns true if the add of @p Ty itself succeeded, +/// false otherwise. +/// +/// FIXME: what to do about extended qualifiers? +bool +BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( + QualType Ty) { + // Insert this type. + if (!MemberPointerTypes.insert(Ty)) + return false; + + const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); + assert(PointerTy && "type was not a member pointer type!"); + + QualType PointeeTy = PointerTy->getPointeeType(); + // Don't add qualified variants of arrays. For one, they're not allowed + // (the qualifier would sink to the element type), and for another, the + // only overload situation where it matters is subscript or pointer +- int, + // and those shouldn't have qualifier variants anyway. + if (PointeeTy->isArrayType()) + return true; + const Type *ClassTy = PointerTy->getClass(); + + // Iterate through all strict supersets of the pointee type's CVR + // qualifiers. + unsigned BaseCVR = PointeeTy.getCVRQualifiers(); + for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { + if ((CVR | BaseCVR) != CVR) continue; + + QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); + MemberPointerTypes.insert( + Context.getMemberPointerType(QPointeeTy, ClassTy)); + } + + return true; +} + +/// AddTypesConvertedFrom - Add each of the types to which the type @p +/// Ty can be implicit converted to the given set of @p Types. We're +/// primarily interested in pointer types and enumeration types. We also +/// take member pointer types, for the conditional operator. +/// AllowUserConversions is true if we should look at the conversion +/// functions of a class type, and AllowExplicitConversions if we +/// should also include the explicit conversion functions of a class +/// type. +void +BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, + SourceLocation Loc, + bool AllowUserConversions, + bool AllowExplicitConversions, + const Qualifiers &VisibleQuals) { + // Only deal with canonical types. + Ty = Context.getCanonicalType(Ty); + + // Look through reference types; they aren't part of the type of an + // expression for the purposes of conversions. + if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) + Ty = RefTy->getPointeeType(); + + // If we're dealing with an array type, decay to the pointer. + if (Ty->isArrayType()) + Ty = SemaRef.Context.getArrayDecayedType(Ty); + + // Otherwise, we don't care about qualifiers on the type. + Ty = Ty.getLocalUnqualifiedType(); + + // Flag if we ever add a non-record type. + const RecordType *TyRec = Ty->getAs<RecordType>(); + HasNonRecordTypes = HasNonRecordTypes || !TyRec; + + // Flag if we encounter an arithmetic type. + HasArithmeticOrEnumeralTypes = + HasArithmeticOrEnumeralTypes || Ty->isArithmeticType(); + + if (Ty->isObjCIdType() || Ty->isObjCClassType()) + PointerTypes.insert(Ty); + else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) { + // Insert our type, and its more-qualified variants, into the set + // of types. + if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) + return; + } else if (Ty->isMemberPointerType()) { + // Member pointers are far easier, since the pointee can't be converted. + if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) + return; + } else if (Ty->isEnumeralType()) { + HasArithmeticOrEnumeralTypes = true; + EnumerationTypes.insert(Ty); + } else if (Ty->isVectorType()) { + // We treat vector types as arithmetic types in many contexts as an + // extension. + HasArithmeticOrEnumeralTypes = true; + VectorTypes.insert(Ty); + } else if (Ty->isNullPtrType()) { + HasNullPtrType = true; + } else if (AllowUserConversions && TyRec) { + // No conversion functions in incomplete types. + if (!SemaRef.isCompleteType(Loc, Ty)) + return; + + CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); + for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) { + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + + // Skip conversion function templates; they don't tell us anything + // about which builtin types we can convert to. + if (isa<FunctionTemplateDecl>(D)) + continue; + + CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); + if (AllowExplicitConversions || !Conv->isExplicit()) { + AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, + VisibleQuals); + } + } + } +} + +/// Helper function for AddBuiltinOperatorCandidates() that adds +/// the volatile- and non-volatile-qualified assignment operators for the +/// given type to the candidate set. +static void AddBuiltinAssignmentOperatorCandidates(Sema &S, + QualType T, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet) { + QualType ParamTypes[2]; + + // T& operator=(T&, T) + ParamTypes[0] = S.Context.getLValueReferenceType(T); + ParamTypes[1] = T; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssignmentOperator=*/true); + + if (!S.Context.getCanonicalType(T).isVolatileQualified()) { + // volatile T& operator=(volatile T&, T) + ParamTypes[0] + = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); + ParamTypes[1] = T; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssignmentOperator=*/true); + } +} + +/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, +/// if any, found in visible type conversion functions found in ArgExpr's type. +static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { + Qualifiers VRQuals; + const RecordType *TyRec; + if (const MemberPointerType *RHSMPType = + ArgExpr->getType()->getAs<MemberPointerType>()) + TyRec = RHSMPType->getClass()->getAs<RecordType>(); + else + TyRec = ArgExpr->getType()->getAs<RecordType>(); + if (!TyRec) { + // Just to be safe, assume the worst case. + VRQuals.addVolatile(); + VRQuals.addRestrict(); + return VRQuals; + } + + CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); + if (!ClassDecl->hasDefinition()) + return VRQuals; + + for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) { + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { + QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); + if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) + CanTy = ResTypeRef->getPointeeType(); + // Need to go down the pointer/mempointer chain and add qualifiers + // as see them. + bool done = false; + while (!done) { + if (CanTy.isRestrictQualified()) + VRQuals.addRestrict(); + if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) + CanTy = ResTypePtr->getPointeeType(); + else if (const MemberPointerType *ResTypeMPtr = + CanTy->getAs<MemberPointerType>()) + CanTy = ResTypeMPtr->getPointeeType(); + else + done = true; + if (CanTy.isVolatileQualified()) + VRQuals.addVolatile(); + if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) + return VRQuals; + } + } + } + return VRQuals; +} + +namespace { + +/// Helper class to manage the addition of builtin operator overload +/// candidates. It provides shared state and utility methods used throughout +/// the process, as well as a helper method to add each group of builtin +/// operator overloads from the standard to a candidate set. +class BuiltinOperatorOverloadBuilder { + // Common instance state available to all overload candidate addition methods. + Sema &S; + ArrayRef<Expr *> Args; + Qualifiers VisibleTypeConversionsQuals; + bool HasArithmeticOrEnumeralCandidateType; + SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes; + OverloadCandidateSet &CandidateSet; + + static constexpr int ArithmeticTypesCap = 24; + SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes; + + // Define some indices used to iterate over the arithemetic types in + // ArithmeticTypes. The "promoted arithmetic types" are the arithmetic + // types are that preserved by promotion (C++ [over.built]p2). + unsigned FirstIntegralType, + LastIntegralType; + unsigned FirstPromotedIntegralType, + LastPromotedIntegralType; + unsigned FirstPromotedArithmeticType, + LastPromotedArithmeticType; + unsigned NumArithmeticTypes; + + void InitArithmeticTypes() { + // Start of promoted types. + FirstPromotedArithmeticType = 0; + ArithmeticTypes.push_back(S.Context.FloatTy); + ArithmeticTypes.push_back(S.Context.DoubleTy); + ArithmeticTypes.push_back(S.Context.LongDoubleTy); + if (S.Context.getTargetInfo().hasFloat128Type()) + ArithmeticTypes.push_back(S.Context.Float128Ty); + + // Start of integral types. + FirstIntegralType = ArithmeticTypes.size(); + FirstPromotedIntegralType = ArithmeticTypes.size(); + ArithmeticTypes.push_back(S.Context.IntTy); + ArithmeticTypes.push_back(S.Context.LongTy); + ArithmeticTypes.push_back(S.Context.LongLongTy); + if (S.Context.getTargetInfo().hasInt128Type()) + ArithmeticTypes.push_back(S.Context.Int128Ty); + ArithmeticTypes.push_back(S.Context.UnsignedIntTy); + ArithmeticTypes.push_back(S.Context.UnsignedLongTy); + ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy); + if (S.Context.getTargetInfo().hasInt128Type()) + ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty); + LastPromotedIntegralType = ArithmeticTypes.size(); + LastPromotedArithmeticType = ArithmeticTypes.size(); + // End of promoted types. + + ArithmeticTypes.push_back(S.Context.BoolTy); + ArithmeticTypes.push_back(S.Context.CharTy); + ArithmeticTypes.push_back(S.Context.WCharTy); + if (S.Context.getLangOpts().Char8) + ArithmeticTypes.push_back(S.Context.Char8Ty); + ArithmeticTypes.push_back(S.Context.Char16Ty); + ArithmeticTypes.push_back(S.Context.Char32Ty); + ArithmeticTypes.push_back(S.Context.SignedCharTy); + ArithmeticTypes.push_back(S.Context.ShortTy); + ArithmeticTypes.push_back(S.Context.UnsignedCharTy); + ArithmeticTypes.push_back(S.Context.UnsignedShortTy); + LastIntegralType = ArithmeticTypes.size(); + NumArithmeticTypes = ArithmeticTypes.size(); + // End of integral types. + // FIXME: What about complex? What about half? + + assert(ArithmeticTypes.size() <= ArithmeticTypesCap && + "Enough inline storage for all arithmetic types."); + } + + /// Helper method to factor out the common pattern of adding overloads + /// for '++' and '--' builtin operators. + void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy, + bool HasVolatile, + bool HasRestrict) { + QualType ParamTypes[2] = { + S.Context.getLValueReferenceType(CandidateTy), + S.Context.IntTy + }; + + // Non-volatile version. + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + + // Use a heuristic to reduce number of builtin candidates in the set: + // add volatile version only if there are conversions to a volatile type. + if (HasVolatile) { + ParamTypes[0] = + S.Context.getLValueReferenceType( + S.Context.getVolatileType(CandidateTy)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + + // Add restrict version only if there are conversions to a restrict type + // and our candidate type is a non-restrict-qualified pointer. + if (HasRestrict && CandidateTy->isAnyPointerType() && + !CandidateTy.isRestrictQualified()) { + ParamTypes[0] + = S.Context.getLValueReferenceType( + S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + + if (HasVolatile) { + ParamTypes[0] + = S.Context.getLValueReferenceType( + S.Context.getCVRQualifiedType(CandidateTy, + (Qualifiers::Volatile | + Qualifiers::Restrict))); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + + } + +public: + BuiltinOperatorOverloadBuilder( + Sema &S, ArrayRef<Expr *> Args, + Qualifiers VisibleTypeConversionsQuals, + bool HasArithmeticOrEnumeralCandidateType, + SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes, + OverloadCandidateSet &CandidateSet) + : S(S), Args(Args), + VisibleTypeConversionsQuals(VisibleTypeConversionsQuals), + HasArithmeticOrEnumeralCandidateType( + HasArithmeticOrEnumeralCandidateType), + CandidateTypes(CandidateTypes), + CandidateSet(CandidateSet) { + + InitArithmeticTypes(); + } + + // Increment is deprecated for bool since C++17. + // + // C++ [over.built]p3: + // + // For every pair (T, VQ), where T is an arithmetic type other + // than bool, and VQ is either volatile or empty, there exist + // candidate operator functions of the form + // + // VQ T& operator++(VQ T&); + // T operator++(VQ T&, int); + // + // C++ [over.built]p4: + // + // For every pair (T, VQ), where T is an arithmetic type other + // than bool, and VQ is either volatile or empty, there exist + // candidate operator functions of the form + // + // VQ T& operator--(VQ T&); + // T operator--(VQ T&, int); + void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) { + const auto TypeOfT = ArithmeticTypes[Arith]; + if (TypeOfT == S.Context.BoolTy) { + if (Op == OO_MinusMinus) + continue; + if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17) + continue; + } + addPlusPlusMinusMinusStyleOverloads( + TypeOfT, + VisibleTypeConversionsQuals.hasVolatile(), + VisibleTypeConversionsQuals.hasRestrict()); + } + } + + // C++ [over.built]p5: + // + // For every pair (T, VQ), where T is a cv-qualified or + // cv-unqualified object type, and VQ is either volatile or + // empty, there exist candidate operator functions of the form + // + // T*VQ& operator++(T*VQ&); + // T*VQ& operator--(T*VQ&); + // T* operator++(T*VQ&, int); + // T* operator--(T*VQ&, int); + void addPlusPlusMinusMinusPointerOverloads() { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + // Skip pointer types that aren't pointers to object types. + if (!(*Ptr)->getPointeeType()->isObjectType()) + continue; + + addPlusPlusMinusMinusStyleOverloads(*Ptr, + (!(*Ptr).isVolatileQualified() && + VisibleTypeConversionsQuals.hasVolatile()), + (!(*Ptr).isRestrictQualified() && + VisibleTypeConversionsQuals.hasRestrict())); + } + } + + // C++ [over.built]p6: + // For every cv-qualified or cv-unqualified object type T, there + // exist candidate operator functions of the form + // + // T& operator*(T*); + // + // C++ [over.built]p7: + // For every function type T that does not have cv-qualifiers or a + // ref-qualifier, there exist candidate operator functions of the form + // T& operator*(T*); + void addUnaryStarPointerOverloads() { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType ParamTy = *Ptr; + QualType PointeeTy = ParamTy->getPointeeType(); + if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType()) + continue; + + if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>()) + if (Proto->getTypeQuals() || Proto->getRefQualifier()) + continue; + + S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet); + } + } + + // C++ [over.built]p9: + // For every promoted arithmetic type T, there exist candidate + // operator functions of the form + // + // T operator+(T); + // T operator-(T); + void addUnaryPlusOrMinusArithmeticOverloads() { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Arith = FirstPromotedArithmeticType; + Arith < LastPromotedArithmeticType; ++Arith) { + QualType ArithTy = ArithmeticTypes[Arith]; + S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet); + } + + // Extension: We also add these operators for vector types. + for (BuiltinCandidateTypeSet::iterator + Vec = CandidateTypes[0].vector_begin(), + VecEnd = CandidateTypes[0].vector_end(); + Vec != VecEnd; ++Vec) { + QualType VecTy = *Vec; + S.AddBuiltinCandidate(&VecTy, Args, CandidateSet); + } + } + + // C++ [over.built]p8: + // For every type T, there exist candidate operator functions of + // the form + // + // T* operator+(T*); + void addUnaryPlusPointerOverloads() { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType ParamTy = *Ptr; + S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet); + } + } + + // C++ [over.built]p10: + // For every promoted integral type T, there exist candidate + // operator functions of the form + // + // T operator~(T); + void addUnaryTildePromotedIntegralOverloads() { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Int = FirstPromotedIntegralType; + Int < LastPromotedIntegralType; ++Int) { + QualType IntTy = ArithmeticTypes[Int]; + S.AddBuiltinCandidate(&IntTy, Args, CandidateSet); + } + + // Extension: We also add this operator for vector types. + for (BuiltinCandidateTypeSet::iterator + Vec = CandidateTypes[0].vector_begin(), + VecEnd = CandidateTypes[0].vector_end(); + Vec != VecEnd; ++Vec) { + QualType VecTy = *Vec; + S.AddBuiltinCandidate(&VecTy, Args, CandidateSet); + } + } + + // C++ [over.match.oper]p16: + // For every pointer to member type T or type std::nullptr_t, there + // exist candidate operator functions of the form + // + // bool operator==(T,T); + // bool operator!=(T,T); + void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() { + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + for (BuiltinCandidateTypeSet::iterator + MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(), + MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end(); + MemPtr != MemPtrEnd; + ++MemPtr) { + // Don't add the same builtin candidate twice. + if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second) + continue; + + QualType ParamTypes[2] = { *MemPtr, *MemPtr }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + + if (CandidateTypes[ArgIdx].hasNullPtrType()) { + CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy); + if (AddedTypes.insert(NullPtrTy).second) { + QualType ParamTypes[2] = { NullPtrTy, NullPtrTy }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + } + + // C++ [over.built]p15: + // + // For every T, where T is an enumeration type or a pointer type, + // there exist candidate operator functions of the form + // + // bool operator<(T, T); + // bool operator>(T, T); + // bool operator<=(T, T); + // bool operator>=(T, T); + // bool operator==(T, T); + // bool operator!=(T, T); + // R operator<=>(T, T) + void addGenericBinaryPointerOrEnumeralOverloads() { + // C++ [over.match.oper]p3: + // [...]the built-in candidates include all of the candidate operator + // functions defined in 13.6 that, compared to the given operator, [...] + // do not have the same parameter-type-list as any non-template non-member + // candidate. + // + // Note that in practice, this only affects enumeration types because there + // aren't any built-in candidates of record type, and a user-defined operator + // must have an operand of record or enumeration type. Also, the only other + // overloaded operator with enumeration arguments, operator=, + // cannot be overloaded for enumeration types, so this is the only place + // where we must suppress candidates like this. + llvm::DenseSet<std::pair<CanQualType, CanQualType> > + UserDefinedBinaryOperators; + + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + if (CandidateTypes[ArgIdx].enumeration_begin() != + CandidateTypes[ArgIdx].enumeration_end()) { + for (OverloadCandidateSet::iterator C = CandidateSet.begin(), + CEnd = CandidateSet.end(); + C != CEnd; ++C) { + if (!C->Viable || !C->Function || C->Function->getNumParams() != 2) + continue; + + if (C->Function->isFunctionTemplateSpecialization()) + continue; + + QualType FirstParamType = + C->Function->getParamDecl(0)->getType().getUnqualifiedType(); + QualType SecondParamType = + C->Function->getParamDecl(1)->getType().getUnqualifiedType(); + + // Skip if either parameter isn't of enumeral type. + if (!FirstParamType->isEnumeralType() || + !SecondParamType->isEnumeralType()) + continue; + + // Add this operator to the set of known user-defined operators. + UserDefinedBinaryOperators.insert( + std::make_pair(S.Context.getCanonicalType(FirstParamType), + S.Context.getCanonicalType(SecondParamType))); + } + } + } + + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[ArgIdx].pointer_begin(), + PtrEnd = CandidateTypes[ArgIdx].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + // Don't add the same builtin candidate twice. + if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second) + continue; + + QualType ParamTypes[2] = { *Ptr, *Ptr }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + for (BuiltinCandidateTypeSet::iterator + Enum = CandidateTypes[ArgIdx].enumeration_begin(), + EnumEnd = CandidateTypes[ArgIdx].enumeration_end(); + Enum != EnumEnd; ++Enum) { + CanQualType CanonType = S.Context.getCanonicalType(*Enum); + + // Don't add the same builtin candidate twice, or if a user defined + // candidate exists. + if (!AddedTypes.insert(CanonType).second || + UserDefinedBinaryOperators.count(std::make_pair(CanonType, + CanonType))) + continue; + QualType ParamTypes[2] = { *Enum, *Enum }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + + // C++ [over.built]p13: + // + // For every cv-qualified or cv-unqualified object type T + // there exist candidate operator functions of the form + // + // T* operator+(T*, ptrdiff_t); + // T& operator[](T*, ptrdiff_t); [BELOW] + // T* operator-(T*, ptrdiff_t); + // T* operator+(ptrdiff_t, T*); + // T& operator[](ptrdiff_t, T*); [BELOW] + // + // C++ [over.built]p14: + // + // For every T, where T is a pointer to object type, there + // exist candidate operator functions of the form + // + // ptrdiff_t operator-(T, T); + void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) { + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (int Arg = 0; Arg < 2; ++Arg) { + QualType AsymmetricParamTypes[2] = { + S.Context.getPointerDiffType(), + S.Context.getPointerDiffType(), + }; + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[Arg].pointer_begin(), + PtrEnd = CandidateTypes[Arg].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType PointeeTy = (*Ptr)->getPointeeType(); + if (!PointeeTy->isObjectType()) + continue; + + AsymmetricParamTypes[Arg] = *Ptr; + if (Arg == 0 || Op == OO_Plus) { + // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) + // T* operator+(ptrdiff_t, T*); + S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet); + } + if (Op == OO_Minus) { + // ptrdiff_t operator-(T, T); + if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second) + continue; + + QualType ParamTypes[2] = { *Ptr, *Ptr }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + } + + // C++ [over.built]p12: + // + // For every pair of promoted arithmetic types L and R, there + // exist candidate operator functions of the form + // + // LR operator*(L, R); + // LR operator/(L, R); + // LR operator+(L, R); + // LR operator-(L, R); + // bool operator<(L, R); + // bool operator>(L, R); + // bool operator<=(L, R); + // bool operator>=(L, R); + // bool operator==(L, R); + // bool operator!=(L, R); + // + // where LR is the result of the usual arithmetic conversions + // between types L and R. + // + // C++ [over.built]p24: + // + // For every pair of promoted arithmetic types L and R, there exist + // candidate operator functions of the form + // + // LR operator?(bool, L, R); + // + // where LR is the result of the usual arithmetic conversions + // between types L and R. + // Our candidates ignore the first parameter. + void addGenericBinaryArithmeticOverloads() { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Left = FirstPromotedArithmeticType; + Left < LastPromotedArithmeticType; ++Left) { + for (unsigned Right = FirstPromotedArithmeticType; + Right < LastPromotedArithmeticType; ++Right) { + QualType LandR[2] = { ArithmeticTypes[Left], + ArithmeticTypes[Right] }; + S.AddBuiltinCandidate(LandR, Args, CandidateSet); + } + } + + // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the + // conditional operator for vector types. + for (BuiltinCandidateTypeSet::iterator + Vec1 = CandidateTypes[0].vector_begin(), + Vec1End = CandidateTypes[0].vector_end(); + Vec1 != Vec1End; ++Vec1) { + for (BuiltinCandidateTypeSet::iterator + Vec2 = CandidateTypes[1].vector_begin(), + Vec2End = CandidateTypes[1].vector_end(); + Vec2 != Vec2End; ++Vec2) { + QualType LandR[2] = { *Vec1, *Vec2 }; + S.AddBuiltinCandidate(LandR, Args, CandidateSet); + } + } + } + + // C++2a [over.built]p14: + // + // For every integral type T there exists a candidate operator function + // of the form + // + // std::strong_ordering operator<=>(T, T) + // + // C++2a [over.built]p15: + // + // For every pair of floating-point types L and R, there exists a candidate + // operator function of the form + // + // std::partial_ordering operator<=>(L, R); + // + // FIXME: The current specification for integral types doesn't play nice with + // the direction of p0946r0, which allows mixed integral and unscoped-enum + // comparisons. Under the current spec this can lead to ambiguity during + // overload resolution. For example: + // + // enum A : int {a}; + // auto x = (a <=> (long)42); + // + // error: call is ambiguous for arguments 'A' and 'long'. + // note: candidate operator<=>(int, int) + // note: candidate operator<=>(long, long) + // + // To avoid this error, this function deviates from the specification and adds + // the mixed overloads `operator<=>(L, R)` where L and R are promoted + // arithmetic types (the same as the generic relational overloads). + // + // For now this function acts as a placeholder. + void addThreeWayArithmeticOverloads() { + addGenericBinaryArithmeticOverloads(); + } + + // C++ [over.built]p17: + // + // For every pair of promoted integral types L and R, there + // exist candidate operator functions of the form + // + // LR operator%(L, R); + // LR operator&(L, R); + // LR operator^(L, R); + // LR operator|(L, R); + // L operator<<(L, R); + // L operator>>(L, R); + // + // where LR is the result of the usual arithmetic conversions + // between types L and R. + void addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op) { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Left = FirstPromotedIntegralType; + Left < LastPromotedIntegralType; ++Left) { + for (unsigned Right = FirstPromotedIntegralType; + Right < LastPromotedIntegralType; ++Right) { + QualType LandR[2] = { ArithmeticTypes[Left], + ArithmeticTypes[Right] }; + S.AddBuiltinCandidate(LandR, Args, CandidateSet); + } + } + } + + // C++ [over.built]p20: + // + // For every pair (T, VQ), where T is an enumeration or + // pointer to member type and VQ is either volatile or + // empty, there exist candidate operator functions of the form + // + // VQ T& operator=(VQ T&, T); + void addAssignmentMemberPointerOrEnumeralOverloads() { + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) { + for (BuiltinCandidateTypeSet::iterator + Enum = CandidateTypes[ArgIdx].enumeration_begin(), + EnumEnd = CandidateTypes[ArgIdx].enumeration_end(); + Enum != EnumEnd; ++Enum) { + if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second) + continue; + + AddBuiltinAssignmentOperatorCandidates(S, *Enum, Args, CandidateSet); + } + + for (BuiltinCandidateTypeSet::iterator + MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(), + MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end(); + MemPtr != MemPtrEnd; ++MemPtr) { + if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second) + continue; + + AddBuiltinAssignmentOperatorCandidates(S, *MemPtr, Args, CandidateSet); + } + } + } + + // C++ [over.built]p19: + // + // For every pair (T, VQ), where T is any type and VQ is either + // volatile or empty, there exist candidate operator functions + // of the form + // + // T*VQ& operator=(T*VQ&, T*); + // + // C++ [over.built]p21: + // + // For every pair (T, VQ), where T is a cv-qualified or + // cv-unqualified object type and VQ is either volatile or + // empty, there exist candidate operator functions of the form + // + // T*VQ& operator+=(T*VQ&, ptrdiff_t); + // T*VQ& operator-=(T*VQ&, ptrdiff_t); + void addAssignmentPointerOverloads(bool isEqualOp) { + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + // If this is operator=, keep track of the builtin candidates we added. + if (isEqualOp) + AddedTypes.insert(S.Context.getCanonicalType(*Ptr)); + else if (!(*Ptr)->getPointeeType()->isObjectType()) + continue; + + // non-volatile version + QualType ParamTypes[2] = { + S.Context.getLValueReferenceType(*Ptr), + isEqualOp ? *Ptr : S.Context.getPointerDiffType(), + }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/ isEqualOp); + + bool NeedVolatile = !(*Ptr).isVolatileQualified() && + VisibleTypeConversionsQuals.hasVolatile(); + if (NeedVolatile) { + // volatile version + ParamTypes[0] = + S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + } + + if (!(*Ptr).isRestrictQualified() && + VisibleTypeConversionsQuals.hasRestrict()) { + // restrict version + ParamTypes[0] + = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + + if (NeedVolatile) { + // volatile restrict version + ParamTypes[0] + = S.Context.getLValueReferenceType( + S.Context.getCVRQualifiedType(*Ptr, + (Qualifiers::Volatile | + Qualifiers::Restrict))); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + } + } + } + + if (isEqualOp) { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[1].pointer_begin(), + PtrEnd = CandidateTypes[1].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + // Make sure we don't add the same candidate twice. + if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second) + continue; + + QualType ParamTypes[2] = { + S.Context.getLValueReferenceType(*Ptr), + *Ptr, + }; + + // non-volatile version + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/true); + + bool NeedVolatile = !(*Ptr).isVolatileQualified() && + VisibleTypeConversionsQuals.hasVolatile(); + if (NeedVolatile) { + // volatile version + ParamTypes[0] = + S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/true); + } + + if (!(*Ptr).isRestrictQualified() && + VisibleTypeConversionsQuals.hasRestrict()) { + // restrict version + ParamTypes[0] + = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr)); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/true); + + if (NeedVolatile) { + // volatile restrict version + ParamTypes[0] + = S.Context.getLValueReferenceType( + S.Context.getCVRQualifiedType(*Ptr, + (Qualifiers::Volatile | + Qualifiers::Restrict))); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/true); + } + } + } + } + } + + // C++ [over.built]p18: + // + // For every triple (L, VQ, R), where L is an arithmetic type, + // VQ is either volatile or empty, and R is a promoted + // arithmetic type, there exist candidate operator functions of + // the form + // + // VQ L& operator=(VQ L&, R); + // VQ L& operator*=(VQ L&, R); + // VQ L& operator/=(VQ L&, R); + // VQ L& operator+=(VQ L&, R); + // VQ L& operator-=(VQ L&, R); + void addAssignmentArithmeticOverloads(bool isEqualOp) { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { + for (unsigned Right = FirstPromotedArithmeticType; + Right < LastPromotedArithmeticType; ++Right) { + QualType ParamTypes[2]; + ParamTypes[1] = ArithmeticTypes[Right]; + + // Add this built-in operator as a candidate (VQ is empty). + ParamTypes[0] = + S.Context.getLValueReferenceType(ArithmeticTypes[Left]); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + + // Add this built-in operator as a candidate (VQ is 'volatile'). + if (VisibleTypeConversionsQuals.hasVolatile()) { + ParamTypes[0] = + S.Context.getVolatileType(ArithmeticTypes[Left]); + ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + } + } + } + + // Extension: Add the binary operators =, +=, -=, *=, /= for vector types. + for (BuiltinCandidateTypeSet::iterator + Vec1 = CandidateTypes[0].vector_begin(), + Vec1End = CandidateTypes[0].vector_end(); + Vec1 != Vec1End; ++Vec1) { + for (BuiltinCandidateTypeSet::iterator + Vec2 = CandidateTypes[1].vector_begin(), + Vec2End = CandidateTypes[1].vector_end(); + Vec2 != Vec2End; ++Vec2) { + QualType ParamTypes[2]; + ParamTypes[1] = *Vec2; + // Add this built-in operator as a candidate (VQ is empty). + ParamTypes[0] = S.Context.getLValueReferenceType(*Vec1); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + + // Add this built-in operator as a candidate (VQ is 'volatile'). + if (VisibleTypeConversionsQuals.hasVolatile()) { + ParamTypes[0] = S.Context.getVolatileType(*Vec1); + ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssigmentOperator=*/isEqualOp); + } + } + } + } + + // C++ [over.built]p22: + // + // For every triple (L, VQ, R), where L is an integral type, VQ + // is either volatile or empty, and R is a promoted integral + // type, there exist candidate operator functions of the form + // + // VQ L& operator%=(VQ L&, R); + // VQ L& operator<<=(VQ L&, R); + // VQ L& operator>>=(VQ L&, R); + // VQ L& operator&=(VQ L&, R); + // VQ L& operator^=(VQ L&, R); + // VQ L& operator|=(VQ L&, R); + void addAssignmentIntegralOverloads() { + if (!HasArithmeticOrEnumeralCandidateType) + return; + + for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { + for (unsigned Right = FirstPromotedIntegralType; + Right < LastPromotedIntegralType; ++Right) { + QualType ParamTypes[2]; + ParamTypes[1] = ArithmeticTypes[Right]; + + // Add this built-in operator as a candidate (VQ is empty). + ParamTypes[0] = + S.Context.getLValueReferenceType(ArithmeticTypes[Left]); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + if (VisibleTypeConversionsQuals.hasVolatile()) { + // Add this built-in operator as a candidate (VQ is 'volatile'). + ParamTypes[0] = ArithmeticTypes[Left]; + ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]); + ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + } + + // C++ [over.operator]p23: + // + // There also exist candidate operator functions of the form + // + // bool operator!(bool); + // bool operator&&(bool, bool); + // bool operator||(bool, bool); + void addExclaimOverload() { + QualType ParamTy = S.Context.BoolTy; + S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet, + /*IsAssignmentOperator=*/false, + /*NumContextualBoolArguments=*/1); + } + void addAmpAmpOrPipePipeOverload() { + QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet, + /*IsAssignmentOperator=*/false, + /*NumContextualBoolArguments=*/2); + } + + // C++ [over.built]p13: + // + // For every cv-qualified or cv-unqualified object type T there + // exist candidate operator functions of the form + // + // T* operator+(T*, ptrdiff_t); [ABOVE] + // T& operator[](T*, ptrdiff_t); + // T* operator-(T*, ptrdiff_t); [ABOVE] + // T* operator+(ptrdiff_t, T*); [ABOVE] + // T& operator[](ptrdiff_t, T*); + void addSubscriptOverloads() { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType ParamTypes[2] = { *Ptr, S.Context.getPointerDiffType() }; + QualType PointeeType = (*Ptr)->getPointeeType(); + if (!PointeeType->isObjectType()) + continue; + + // T& operator[](T*, ptrdiff_t) + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[1].pointer_begin(), + PtrEnd = CandidateTypes[1].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType ParamTypes[2] = { S.Context.getPointerDiffType(), *Ptr }; + QualType PointeeType = (*Ptr)->getPointeeType(); + if (!PointeeType->isObjectType()) + continue; + + // T& operator[](ptrdiff_t, T*) + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + + // C++ [over.built]p11: + // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, + // C1 is the same type as C2 or is a derived class of C2, T is an object + // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, + // there exist candidate operator functions of the form + // + // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); + // + // where CV12 is the union of CV1 and CV2. + void addArrowStarOverloads() { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[0].pointer_begin(), + PtrEnd = CandidateTypes[0].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + QualType C1Ty = (*Ptr); + QualType C1; + QualifierCollector Q1; + C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0); + if (!isa<RecordType>(C1)) + continue; + // heuristic to reduce number of builtin candidates in the set. + // Add volatile/restrict version only if there are conversions to a + // volatile/restrict type. + if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) + continue; + if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) + continue; + for (BuiltinCandidateTypeSet::iterator + MemPtr = CandidateTypes[1].member_pointer_begin(), + MemPtrEnd = CandidateTypes[1].member_pointer_end(); + MemPtr != MemPtrEnd; ++MemPtr) { + const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); + QualType C2 = QualType(mptr->getClass(), 0); + C2 = C2.getUnqualifiedType(); + if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2)) + break; + QualType ParamTypes[2] = { *Ptr, *MemPtr }; + // build CV12 T& + QualType T = mptr->getPointeeType(); + if (!VisibleTypeConversionsQuals.hasVolatile() && + T.isVolatileQualified()) + continue; + if (!VisibleTypeConversionsQuals.hasRestrict() && + T.isRestrictQualified()) + continue; + T = Q1.apply(S.Context, T); + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + + // Note that we don't consider the first argument, since it has been + // contextually converted to bool long ago. The candidates below are + // therefore added as binary. + // + // C++ [over.built]p25: + // For every type T, where T is a pointer, pointer-to-member, or scoped + // enumeration type, there exist candidate operator functions of the form + // + // T operator?(bool, T, T); + // + void addConditionalOperatorOverloads() { + /// Set of (canonical) types that we've already handled. + llvm::SmallPtrSet<QualType, 8> AddedTypes; + + for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) { + for (BuiltinCandidateTypeSet::iterator + Ptr = CandidateTypes[ArgIdx].pointer_begin(), + PtrEnd = CandidateTypes[ArgIdx].pointer_end(); + Ptr != PtrEnd; ++Ptr) { + if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second) + continue; + + QualType ParamTypes[2] = { *Ptr, *Ptr }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + + for (BuiltinCandidateTypeSet::iterator + MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(), + MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end(); + MemPtr != MemPtrEnd; ++MemPtr) { + if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second) + continue; + + QualType ParamTypes[2] = { *MemPtr, *MemPtr }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + + if (S.getLangOpts().CPlusPlus11) { + for (BuiltinCandidateTypeSet::iterator + Enum = CandidateTypes[ArgIdx].enumeration_begin(), + EnumEnd = CandidateTypes[ArgIdx].enumeration_end(); + Enum != EnumEnd; ++Enum) { + if (!(*Enum)->getAs<EnumType>()->getDecl()->isScoped()) + continue; + + if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second) + continue; + + QualType ParamTypes[2] = { *Enum, *Enum }; + S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet); + } + } + } + } +}; + +} // end anonymous namespace + +/// AddBuiltinOperatorCandidates - Add the appropriate built-in +/// operator overloads to the candidate set (C++ [over.built]), based +/// on the operator @p Op and the arguments given. For example, if the +/// operator is a binary '+', this routine might add "int +/// operator+(int, int)" to cover integer addition. +void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, + SourceLocation OpLoc, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet) { + // Find all of the types that the arguments can convert to, but only + // if the operator we're looking at has built-in operator candidates + // that make use of these types. Also record whether we encounter non-record + // candidate types or either arithmetic or enumeral candidate types. + Qualifiers VisibleTypeConversionsQuals; + VisibleTypeConversionsQuals.addConst(); + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) + VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); + + bool HasNonRecordCandidateType = false; + bool HasArithmeticOrEnumeralCandidateType = false; + SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes; + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + CandidateTypes.emplace_back(*this); + CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(), + OpLoc, + true, + (Op == OO_Exclaim || + Op == OO_AmpAmp || + Op == OO_PipePipe), + VisibleTypeConversionsQuals); + HasNonRecordCandidateType = HasNonRecordCandidateType || + CandidateTypes[ArgIdx].hasNonRecordTypes(); + HasArithmeticOrEnumeralCandidateType = + HasArithmeticOrEnumeralCandidateType || + CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes(); + } + + // Exit early when no non-record types have been added to the candidate set + // for any of the arguments to the operator. + // + // We can't exit early for !, ||, or &&, since there we have always have + // 'bool' overloads. + if (!HasNonRecordCandidateType && + !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe)) + return; + + // Setup an object to manage the common state for building overloads. + BuiltinOperatorOverloadBuilder OpBuilder(*this, Args, + VisibleTypeConversionsQuals, + HasArithmeticOrEnumeralCandidateType, + CandidateTypes, CandidateSet); + + // Dispatch over the operation to add in only those overloads which apply. + switch (Op) { + case OO_None: + case NUM_OVERLOADED_OPERATORS: + llvm_unreachable("Expected an overloaded operator"); + + case OO_New: + case OO_Delete: + case OO_Array_New: + case OO_Array_Delete: + case OO_Call: + llvm_unreachable( + "Special operators don't use AddBuiltinOperatorCandidates"); + + case OO_Comma: + case OO_Arrow: + case OO_Coawait: + // C++ [over.match.oper]p3: + // -- For the operator ',', the unary operator '&', the + // operator '->', or the operator 'co_await', the + // built-in candidates set is empty. + break; + + case OO_Plus: // '+' is either unary or binary + if (Args.size() == 1) + OpBuilder.addUnaryPlusPointerOverloads(); + LLVM_FALLTHROUGH; + + case OO_Minus: // '-' is either unary or binary + if (Args.size() == 1) { + OpBuilder.addUnaryPlusOrMinusArithmeticOverloads(); + } else { + OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op); + OpBuilder.addGenericBinaryArithmeticOverloads(); + } + break; + + case OO_Star: // '*' is either unary or binary + if (Args.size() == 1) + OpBuilder.addUnaryStarPointerOverloads(); + else + OpBuilder.addGenericBinaryArithmeticOverloads(); + break; + + case OO_Slash: + OpBuilder.addGenericBinaryArithmeticOverloads(); + break; + + case OO_PlusPlus: + case OO_MinusMinus: + OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op); + OpBuilder.addPlusPlusMinusMinusPointerOverloads(); + break; + + case OO_EqualEqual: + case OO_ExclaimEqual: + OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads(); + LLVM_FALLTHROUGH; + + case OO_Less: + case OO_Greater: + case OO_LessEqual: + case OO_GreaterEqual: + OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(); + OpBuilder.addGenericBinaryArithmeticOverloads(); + break; + + case OO_Spaceship: + OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(); + OpBuilder.addThreeWayArithmeticOverloads(); + break; + + case OO_Percent: + case OO_Caret: + case OO_Pipe: + case OO_LessLess: + case OO_GreaterGreater: + OpBuilder.addBinaryBitwiseArithmeticOverloads(Op); + break; + + case OO_Amp: // '&' is either unary or binary + if (Args.size() == 1) + // C++ [over.match.oper]p3: + // -- For the operator ',', the unary operator '&', or the + // operator '->', the built-in candidates set is empty. + break; + + OpBuilder.addBinaryBitwiseArithmeticOverloads(Op); + break; + + case OO_Tilde: + OpBuilder.addUnaryTildePromotedIntegralOverloads(); + break; + + case OO_Equal: + OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads(); + LLVM_FALLTHROUGH; + + case OO_PlusEqual: + case OO_MinusEqual: + OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal); + LLVM_FALLTHROUGH; + + case OO_StarEqual: + case OO_SlashEqual: + OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal); + break; + + case OO_PercentEqual: + case OO_LessLessEqual: + case OO_GreaterGreaterEqual: + case OO_AmpEqual: + case OO_CaretEqual: + case OO_PipeEqual: + OpBuilder.addAssignmentIntegralOverloads(); + break; + + case OO_Exclaim: + OpBuilder.addExclaimOverload(); + break; + + case OO_AmpAmp: + case OO_PipePipe: + OpBuilder.addAmpAmpOrPipePipeOverload(); + break; + + case OO_Subscript: + OpBuilder.addSubscriptOverloads(); + break; + + case OO_ArrowStar: + OpBuilder.addArrowStarOverloads(); + break; + + case OO_Conditional: + OpBuilder.addConditionalOperatorOverloads(); + OpBuilder.addGenericBinaryArithmeticOverloads(); + break; + } +} + +/// Add function candidates found via argument-dependent lookup +/// to the set of overloading candidates. +/// +/// This routine performs argument-dependent name lookup based on the +/// given function name (which may also be an operator name) and adds +/// all of the overload candidates found by ADL to the overload +/// candidate set (C++ [basic.lookup.argdep]). +void +Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, + SourceLocation Loc, + ArrayRef<Expr *> Args, + TemplateArgumentListInfo *ExplicitTemplateArgs, + OverloadCandidateSet& CandidateSet, + bool PartialOverloading) { + ADLResult Fns; + + // FIXME: This approach for uniquing ADL results (and removing + // redundant candidates from the set) relies on pointer-equality, + // which means we need to key off the canonical decl. However, + // always going back to the canonical decl might not get us the + // right set of default arguments. What default arguments are + // we supposed to consider on ADL candidates, anyway? + + // FIXME: Pass in the explicit template arguments? + ArgumentDependentLookup(Name, Loc, Args, Fns); + + // Erase all of the candidates we already knew about. + for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), + CandEnd = CandidateSet.end(); + Cand != CandEnd; ++Cand) + if (Cand->Function) { + Fns.erase(Cand->Function); + if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) + Fns.erase(FunTmpl); + } + + // For each of the ADL candidates we found, add it to the overload + // set. + for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { + DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); + + if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { + if (ExplicitTemplateArgs) + continue; + + AddOverloadCandidate(FD, FoundDecl, Args, CandidateSet, + /*SupressUserConversions=*/false, PartialOverloading, + /*AllowExplicit=*/false, ADLCallKind::UsesADL); + } else { + AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), FoundDecl, + ExplicitTemplateArgs, Args, CandidateSet, + /*SupressUserConversions=*/false, + PartialOverloading, ADLCallKind::UsesADL); + } + } +} + +namespace { +enum class Comparison { Equal, Better, Worse }; +} + +/// Compares the enable_if attributes of two FunctionDecls, for the purposes of +/// overload resolution. +/// +/// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff +/// Cand1's first N enable_if attributes have precisely the same conditions as +/// Cand2's first N enable_if attributes (where N = the number of enable_if +/// attributes on Cand2), and Cand1 has more than N enable_if attributes. +/// +/// Note that you can have a pair of candidates such that Cand1's enable_if +/// attributes are worse than Cand2's, and Cand2's enable_if attributes are +/// worse than Cand1's. +static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1, + const FunctionDecl *Cand2) { + // Common case: One (or both) decls don't have enable_if attrs. + bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>(); + bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>(); + if (!Cand1Attr || !Cand2Attr) { + if (Cand1Attr == Cand2Attr) + return Comparison::Equal; + return Cand1Attr ? Comparison::Better : Comparison::Worse; + } + + auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>(); + auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>(); + + llvm::FoldingSetNodeID Cand1ID, Cand2ID; + for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) { + Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair); + Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair); + + // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1 + // has fewer enable_if attributes than Cand2, and vice versa. + if (!Cand1A) + return Comparison::Worse; + if (!Cand2A) + return Comparison::Better; + + Cand1ID.clear(); + Cand2ID.clear(); + + (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true); + (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true); + if (Cand1ID != Cand2ID) + return Comparison::Worse; + } + + return Comparison::Equal; +} + +static bool isBetterMultiversionCandidate(const OverloadCandidate &Cand1, + const OverloadCandidate &Cand2) { + if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function || + !Cand2.Function->isMultiVersion()) + return false; + + // If Cand1 is invalid, it cannot be a better match, if Cand2 is invalid, this + // is obviously better. + if (Cand1.Function->isInvalidDecl()) return false; + if (Cand2.Function->isInvalidDecl()) return true; + + // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer + // cpu_dispatch, else arbitrarily based on the identifiers. + bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>(); + bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>(); + const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>(); + const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>(); + + if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec) + return false; + + if (Cand1CPUDisp && !Cand2CPUDisp) + return true; + if (Cand2CPUDisp && !Cand1CPUDisp) + return false; + + if (Cand1CPUSpec && Cand2CPUSpec) { + if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size()) + return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size(); + + std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator> + FirstDiff = std::mismatch( + Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(), + Cand2CPUSpec->cpus_begin(), + [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) { + return LHS->getName() == RHS->getName(); + }); + + assert(FirstDiff.first != Cand1CPUSpec->cpus_end() && + "Two different cpu-specific versions should not have the same " + "identifier list, otherwise they'd be the same decl!"); + return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName(); + } + llvm_unreachable("No way to get here unless both had cpu_dispatch"); +} + +/// isBetterOverloadCandidate - Determines whether the first overload +/// candidate is a better candidate than the second (C++ 13.3.3p1). +bool clang::isBetterOverloadCandidate( + Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2, + SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) { + // Define viable functions to be better candidates than non-viable + // functions. + if (!Cand2.Viable) + return Cand1.Viable; + else if (!Cand1.Viable) + return false; + + // C++ [over.match.best]p1: + // + // -- if F is a static member function, ICS1(F) is defined such + // that ICS1(F) is neither better nor worse than ICS1(G) for + // any function G, and, symmetrically, ICS1(G) is neither + // better nor worse than ICS1(F). + unsigned StartArg = 0; + if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) + StartArg = 1; + + auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) { + // We don't allow incompatible pointer conversions in C++. + if (!S.getLangOpts().CPlusPlus) + return ICS.isStandard() && + ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion; + + // The only ill-formed conversion we allow in C++ is the string literal to + // char* conversion, which is only considered ill-formed after C++11. + return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings && + hasDeprecatedStringLiteralToCharPtrConversion(ICS); + }; + + // Define functions that don't require ill-formed conversions for a given + // argument to be better candidates than functions that do. + unsigned NumArgs = Cand1.Conversions.size(); + assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); + bool HasBetterConversion = false; + for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { + bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]); + bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]); + if (Cand1Bad != Cand2Bad) { + if (Cand1Bad) + return false; + HasBetterConversion = true; + } + } + + if (HasBetterConversion) + return true; + + // C++ [over.match.best]p1: + // A viable function F1 is defined to be a better function than another + // viable function F2 if for all arguments i, ICSi(F1) is not a worse + // conversion sequence than ICSi(F2), and then... + for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { + switch (CompareImplicitConversionSequences(S, Loc, + Cand1.Conversions[ArgIdx], + Cand2.Conversions[ArgIdx])) { + case ImplicitConversionSequence::Better: + // Cand1 has a better conversion sequence. + HasBetterConversion = true; + break; + + case ImplicitConversionSequence::Worse: + // Cand1 can't be better than Cand2. + return false; + + case ImplicitConversionSequence::Indistinguishable: + // Do nothing. + break; + } + } + + // -- for some argument j, ICSj(F1) is a better conversion sequence than + // ICSj(F2), or, if not that, + if (HasBetterConversion) + return true; + + // -- the context is an initialization by user-defined conversion + // (see 8.5, 13.3.1.5) and the standard conversion sequence + // from the return type of F1 to the destination type (i.e., + // the type of the entity being initialized) is a better + // conversion sequence than the standard conversion sequence + // from the return type of F2 to the destination type. + if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion && + Cand1.Function && Cand2.Function && + isa<CXXConversionDecl>(Cand1.Function) && + isa<CXXConversionDecl>(Cand2.Function)) { + // First check whether we prefer one of the conversion functions over the + // other. This only distinguishes the results in non-standard, extension + // cases such as the conversion from a lambda closure type to a function + // pointer or block. + ImplicitConversionSequence::CompareKind Result = + compareConversionFunctions(S, Cand1.Function, Cand2.Function); + if (Result == ImplicitConversionSequence::Indistinguishable) + Result = CompareStandardConversionSequences(S, Loc, + Cand1.FinalConversion, + Cand2.FinalConversion); + + if (Result != ImplicitConversionSequence::Indistinguishable) + return Result == ImplicitConversionSequence::Better; + + // FIXME: Compare kind of reference binding if conversion functions + // convert to a reference type used in direct reference binding, per + // C++14 [over.match.best]p1 section 2 bullet 3. + } + + // FIXME: Work around a defect in the C++17 guaranteed copy elision wording, + // as combined with the resolution to CWG issue 243. + // + // When the context is initialization by constructor ([over.match.ctor] or + // either phase of [over.match.list]), a constructor is preferred over + // a conversion function. + if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 && + Cand1.Function && Cand2.Function && + isa<CXXConstructorDecl>(Cand1.Function) != + isa<CXXConstructorDecl>(Cand2.Function)) + return isa<CXXConstructorDecl>(Cand1.Function); + + // -- F1 is a non-template function and F2 is a function template + // specialization, or, if not that, + bool Cand1IsSpecialization = Cand1.Function && + Cand1.Function->getPrimaryTemplate(); + bool Cand2IsSpecialization = Cand2.Function && + Cand2.Function->getPrimaryTemplate(); + if (Cand1IsSpecialization != Cand2IsSpecialization) + return Cand2IsSpecialization; + + // -- F1 and F2 are function template specializations, and the function + // template for F1 is more specialized than the template for F2 + // according to the partial ordering rules described in 14.5.5.2, or, + // if not that, + if (Cand1IsSpecialization && Cand2IsSpecialization) { + if (FunctionTemplateDecl *BetterTemplate + = S.getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), + Cand2.Function->getPrimaryTemplate(), + Loc, + isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion + : TPOC_Call, + Cand1.ExplicitCallArguments, + Cand2.ExplicitCallArguments)) + return BetterTemplate == Cand1.Function->getPrimaryTemplate(); + } + + // FIXME: Work around a defect in the C++17 inheriting constructor wording. + // A derived-class constructor beats an (inherited) base class constructor. + bool Cand1IsInherited = + dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl()); + bool Cand2IsInherited = + dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl()); + if (Cand1IsInherited != Cand2IsInherited) + return Cand2IsInherited; + else if (Cand1IsInherited) { + assert(Cand2IsInherited); + auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext()); + auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext()); + if (Cand1Class->isDerivedFrom(Cand2Class)) + return true; + if (Cand2Class->isDerivedFrom(Cand1Class)) + return false; + // Inherited from sibling base classes: still ambiguous. + } + + // Check C++17 tie-breakers for deduction guides. + { + auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function); + auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function); + if (Guide1 && Guide2) { + // -- F1 is generated from a deduction-guide and F2 is not + if (Guide1->isImplicit() != Guide2->isImplicit()) + return Guide2->isImplicit(); + + // -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not + if (Guide1->isCopyDeductionCandidate()) + return true; + } + } + + // Check for enable_if value-based overload resolution. + if (Cand1.Function && Cand2.Function) { + Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function); + if (Cmp != Comparison::Equal) + return Cmp == Comparison::Better; + } + + if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) { + FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext); + return S.IdentifyCUDAPreference(Caller, Cand1.Function) > + S.IdentifyCUDAPreference(Caller, Cand2.Function); + } + + bool HasPS1 = Cand1.Function != nullptr && + functionHasPassObjectSizeParams(Cand1.Function); + bool HasPS2 = Cand2.Function != nullptr && + functionHasPassObjectSizeParams(Cand2.Function); + if (HasPS1 != HasPS2 && HasPS1) + return true; + + return isBetterMultiversionCandidate(Cand1, Cand2); +} + +/// Determine whether two declarations are "equivalent" for the purposes of +/// name lookup and overload resolution. This applies when the same internal/no +/// linkage entity is defined by two modules (probably by textually including +/// the same header). In such a case, we don't consider the declarations to +/// declare the same entity, but we also don't want lookups with both +/// declarations visible to be ambiguous in some cases (this happens when using +/// a modularized libstdc++). +bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A, + const NamedDecl *B) { + auto *VA = dyn_cast_or_null<ValueDecl>(A); + auto *VB = dyn_cast_or_null<ValueDecl>(B); + if (!VA || !VB) + return false; + + // The declarations must be declaring the same name as an internal linkage + // entity in different modules. + if (!VA->getDeclContext()->getRedeclContext()->Equals( + VB->getDeclContext()->getRedeclContext()) || + getOwningModule(const_cast<ValueDecl *>(VA)) == + getOwningModule(const_cast<ValueDecl *>(VB)) || + VA->isExternallyVisible() || VB->isExternallyVisible()) + return false; + + // Check that the declarations appear to be equivalent. + // + // FIXME: Checking the type isn't really enough to resolve the ambiguity. + // For constants and functions, we should check the initializer or body is + // the same. For non-constant variables, we shouldn't allow it at all. + if (Context.hasSameType(VA->getType(), VB->getType())) + return true; + + // Enum constants within unnamed enumerations will have different types, but + // may still be similar enough to be interchangeable for our purposes. + if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) { + if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) { + // Only handle anonymous enums. If the enumerations were named and + // equivalent, they would have been merged to the same type. + auto *EnumA = cast<EnumDecl>(EA->getDeclContext()); + auto *EnumB = cast<EnumDecl>(EB->getDeclContext()); + if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() || + !Context.hasSameType(EnumA->getIntegerType(), + EnumB->getIntegerType())) + return false; + // Allow this only if the value is the same for both enumerators. + return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal()); + } + } + + // Nothing else is sufficiently similar. + return false; +} + +void Sema::diagnoseEquivalentInternalLinkageDeclarations( + SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) { + Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D; + + Module *M = getOwningModule(const_cast<NamedDecl*>(D)); + Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl) + << !M << (M ? M->getFullModuleName() : ""); + + for (auto *E : Equiv) { + Module *M = getOwningModule(const_cast<NamedDecl*>(E)); + Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl) + << !M << (M ? M->getFullModuleName() : ""); + } +} + +/// Computes the best viable function (C++ 13.3.3) +/// within an overload candidate set. +/// +/// \param Loc The location of the function name (or operator symbol) for +/// which overload resolution occurs. +/// +/// \param Best If overload resolution was successful or found a deleted +/// function, \p Best points to the candidate function found. +/// +/// \returns The result of overload resolution. +OverloadingResult +OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc, + iterator &Best) { + llvm::SmallVector<OverloadCandidate *, 16> Candidates; + std::transform(begin(), end(), std::back_inserter(Candidates), + [](OverloadCandidate &Cand) { return &Cand; }); + + // [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but + // are accepted by both clang and NVCC. However, during a particular + // compilation mode only one call variant is viable. We need to + // exclude non-viable overload candidates from consideration based + // only on their host/device attributes. Specifically, if one + // candidate call is WrongSide and the other is SameSide, we ignore + // the WrongSide candidate. + if (S.getLangOpts().CUDA) { + const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext); + bool ContainsSameSideCandidate = + llvm::any_of(Candidates, [&](OverloadCandidate *Cand) { + return Cand->Function && + S.IdentifyCUDAPreference(Caller, Cand->Function) == + Sema::CFP_SameSide; + }); + if (ContainsSameSideCandidate) { + auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) { + return Cand->Function && + S.IdentifyCUDAPreference(Caller, Cand->Function) == + Sema::CFP_WrongSide; + }; + llvm::erase_if(Candidates, IsWrongSideCandidate); + } + } + + // Find the best viable function. + Best = end(); + for (auto *Cand : Candidates) + if (Cand->Viable) + if (Best == end() || + isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind)) + Best = Cand; + + // If we didn't find any viable functions, abort. + if (Best == end()) + return OR_No_Viable_Function; + + llvm::SmallVector<const NamedDecl *, 4> EquivalentCands; + + // Make sure that this function is better than every other viable + // function. If not, we have an ambiguity. + for (auto *Cand : Candidates) { + if (Cand->Viable && Cand != Best && + !isBetterOverloadCandidate(S, *Best, *Cand, Loc, Kind)) { + if (S.isEquivalentInternalLinkageDeclaration(Best->Function, + Cand->Function)) { + EquivalentCands.push_back(Cand->Function); + continue; + } + + Best = end(); + return OR_Ambiguous; + } + } + + // Best is the best viable function. + if (Best->Function && + (Best->Function->isDeleted() || + S.isFunctionConsideredUnavailable(Best->Function))) + return OR_Deleted; + + if (!EquivalentCands.empty()) + S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function, + EquivalentCands); + + return OR_Success; +} + +namespace { + +enum OverloadCandidateKind { + oc_function, + oc_method, + oc_constructor, + oc_implicit_default_constructor, + oc_implicit_copy_constructor, + oc_implicit_move_constructor, + oc_implicit_copy_assignment, + oc_implicit_move_assignment, + oc_inherited_constructor +}; + +enum OverloadCandidateSelect { + ocs_non_template, + ocs_template, + ocs_described_template, +}; + +static std::pair<OverloadCandidateKind, OverloadCandidateSelect> +ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn, + std::string &Description) { + + bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl(); + if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { + isTemplate = true; + Description = S.getTemplateArgumentBindingsText( + FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); + } + + OverloadCandidateSelect Select = [&]() { + if (!Description.empty()) + return ocs_described_template; + return isTemplate ? ocs_template : ocs_non_template; + }(); + + OverloadCandidateKind Kind = [&]() { + if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { + if (!Ctor->isImplicit()) { + if (isa<ConstructorUsingShadowDecl>(Found)) + return oc_inherited_constructor; + else + return oc_constructor; + } + + if (Ctor->isDefaultConstructor()) + return oc_implicit_default_constructor; + + if (Ctor->isMoveConstructor()) + return oc_implicit_move_constructor; + + assert(Ctor->isCopyConstructor() && + "unexpected sort of implicit constructor"); + return oc_implicit_copy_constructor; + } + + if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { + // This actually gets spelled 'candidate function' for now, but + // it doesn't hurt to split it out. + if (!Meth->isImplicit()) + return oc_method; + + if (Meth->isMoveAssignmentOperator()) + return oc_implicit_move_assignment; + + if (Meth->isCopyAssignmentOperator()) + return oc_implicit_copy_assignment; + + assert(isa<CXXConversionDecl>(Meth) && "expected conversion"); + return oc_method; + } + + return oc_function; + }(); + + return std::make_pair(Kind, Select); +} + +void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) { + // FIXME: It'd be nice to only emit a note once per using-decl per overload + // set. + if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl)) + S.Diag(FoundDecl->getLocation(), + diag::note_ovl_candidate_inherited_constructor) + << Shadow->getNominatedBaseClass(); +} + +} // end anonymous namespace + +static bool isFunctionAlwaysEnabled(const ASTContext &Ctx, + const FunctionDecl *FD) { + for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) { + bool AlwaysTrue; + if (!EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx)) + return false; + if (!AlwaysTrue) + return false; + } + return true; +} + +/// Returns true if we can take the address of the function. +/// +/// \param Complain - If true, we'll emit a diagnostic +/// \param InOverloadResolution - For the purposes of emitting a diagnostic, are +/// we in overload resolution? +/// \param Loc - The location of the statement we're complaining about. Ignored +/// if we're not complaining, or if we're in overload resolution. +static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD, + bool Complain, + bool InOverloadResolution, + SourceLocation Loc) { + if (!isFunctionAlwaysEnabled(S.Context, FD)) { + if (Complain) { + if (InOverloadResolution) + S.Diag(FD->getBeginLoc(), + diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr); + else + S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD; + } + return false; + } + + auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) { + return P->hasAttr<PassObjectSizeAttr>(); + }); + if (I == FD->param_end()) + return true; + + if (Complain) { + // Add one to ParamNo because it's user-facing + unsigned ParamNo = std::distance(FD->param_begin(), I) + 1; + if (InOverloadResolution) + S.Diag(FD->getLocation(), + diag::note_ovl_candidate_has_pass_object_size_params) + << ParamNo; + else + S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params) + << FD << ParamNo; + } + return false; +} + +static bool checkAddressOfCandidateIsAvailable(Sema &S, + const FunctionDecl *FD) { + return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true, + /*InOverloadResolution=*/true, + /*Loc=*/SourceLocation()); +} + +bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function, + bool Complain, + SourceLocation Loc) { + return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain, + /*InOverloadResolution=*/false, + Loc); +} + +// Notes the location of an overload candidate. +void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn, + QualType DestType, bool TakingAddress) { + if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn)) + return; + if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() && + !Fn->getAttr<TargetAttr>()->isDefaultVersion()) + return; + + std::string FnDesc; + std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair = + ClassifyOverloadCandidate(*this, Found, Fn, FnDesc); + PartialDiagnostic PD = PDiag(diag::note_ovl_candidate) + << (unsigned)KSPair.first << (unsigned)KSPair.second + << Fn << FnDesc; + + HandleFunctionTypeMismatch(PD, Fn->getType(), DestType); + Diag(Fn->getLocation(), PD); + MaybeEmitInheritedConstructorNote(*this, Found); +} + +// Notes the location of all overload candidates designated through +// OverloadedExpr +void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType, + bool TakingAddress) { + assert(OverloadedExpr->getType() == Context.OverloadTy); + + OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr); + OverloadExpr *OvlExpr = Ovl.Expression; + + for (UnresolvedSetIterator I = OvlExpr->decls_begin(), + IEnd = OvlExpr->decls_end(); + I != IEnd; ++I) { + if (FunctionTemplateDecl *FunTmpl = + dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) { + NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), DestType, + TakingAddress); + } else if (FunctionDecl *Fun + = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) { + NoteOverloadCandidate(*I, Fun, DestType, TakingAddress); + } + } +} + +/// Diagnoses an ambiguous conversion. The partial diagnostic is the +/// "lead" diagnostic; it will be given two arguments, the source and +/// target types of the conversion. +void ImplicitConversionSequence::DiagnoseAmbiguousConversion( + Sema &S, + SourceLocation CaretLoc, + const PartialDiagnostic &PDiag) const { + S.Diag(CaretLoc, PDiag) + << Ambiguous.getFromType() << Ambiguous.getToType(); + // FIXME: The note limiting machinery is borrowed from + // OverloadCandidateSet::NoteCandidates; there's an opportunity for + // refactoring here. + const OverloadsShown ShowOverloads = S.Diags.getShowOverloads(); + unsigned CandsShown = 0; + AmbiguousConversionSequence::const_iterator I, E; + for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) { + if (CandsShown >= 4 && ShowOverloads == Ovl_Best) + break; + ++CandsShown; + S.NoteOverloadCandidate(I->first, I->second); + } + if (I != E) + S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I); +} + +static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, + unsigned I, bool TakingCandidateAddress) { + const ImplicitConversionSequence &Conv = Cand->Conversions[I]; + assert(Conv.isBad()); + assert(Cand->Function && "for now, candidate must be a function"); + FunctionDecl *Fn = Cand->Function; + + // There's a conversion slot for the object argument if this is a + // non-constructor method. Note that 'I' corresponds the + // conversion-slot index. + bool isObjectArgument = false; + if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { + if (I == 0) + isObjectArgument = true; + else + I--; + } + + std::string FnDesc; + std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair = + ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, FnDesc); + + Expr *FromExpr = Conv.Bad.FromExpr; + QualType FromTy = Conv.Bad.getFromType(); + QualType ToTy = Conv.Bad.getToType(); + + if (FromTy == S.Context.OverloadTy) { + assert(FromExpr && "overload set argument came from implicit argument?"); + Expr *E = FromExpr->IgnoreParens(); + if (isa<UnaryOperator>(E)) + E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); + DeclarationName Name = cast<OverloadExpr>(E)->getName(); + + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy + << Name << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + // Do some hand-waving analysis to see if the non-viability is due + // to a qualifier mismatch. + CanQualType CFromTy = S.Context.getCanonicalType(FromTy); + CanQualType CToTy = S.Context.getCanonicalType(ToTy); + if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) + CToTy = RT->getPointeeType(); + else { + // TODO: detect and diagnose the full richness of const mismatches. + if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) + if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) { + CFromTy = FromPT->getPointeeType(); + CToTy = ToPT->getPointeeType(); + } + } + + if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && + !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { + Qualifiers FromQs = CFromTy.getQualifiers(); + Qualifiers ToQs = CToTy.getQualifiers(); + + if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << ToTy << (unsigned)isObjectArgument << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << FromQs.getObjCLifetime() << ToQs.getObjCLifetime() + << (unsigned)isObjectArgument << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr() + << (unsigned)isObjectArgument << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << FromQs.hasUnaligned() << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); + assert(CVR && "unexpected qualifiers mismatch"); + + if (isObjectArgument) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << (CVR - 1); + } else { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << (CVR - 1) << I + 1; + } + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + // Special diagnostic for failure to convert an initializer list, since + // telling the user that it has type void is not useful. + if (FromExpr && isa<InitListExpr>(FromExpr)) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << ToTy << (unsigned)isObjectArgument << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + // Diagnose references or pointers to incomplete types differently, + // since it's far from impossible that the incompleteness triggered + // the failure. + QualType TempFromTy = FromTy.getNonReferenceType(); + if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) + TempFromTy = PTy->getPointeeType(); + if (TempFromTy->isIncompleteType()) { + // Emit the generic diagnostic and, optionally, add the hints to it. + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << ToTy << (unsigned)isObjectArgument << I + 1 + << (unsigned)(Cand->Fix.Kind); + + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + // Diagnose base -> derived pointer conversions. + unsigned BaseToDerivedConversion = 0; + if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) { + if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) { + if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs( + FromPtrTy->getPointeeType()) && + !FromPtrTy->getPointeeType()->isIncompleteType() && + !ToPtrTy->getPointeeType()->isIncompleteType() && + S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(), + FromPtrTy->getPointeeType())) + BaseToDerivedConversion = 1; + } + } else if (const ObjCObjectPointerType *FromPtrTy + = FromTy->getAs<ObjCObjectPointerType>()) { + if (const ObjCObjectPointerType *ToPtrTy + = ToTy->getAs<ObjCObjectPointerType>()) + if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl()) + if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl()) + if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs( + FromPtrTy->getPointeeType()) && + FromIface->isSuperClassOf(ToIface)) + BaseToDerivedConversion = 2; + } else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) { + if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) && + !FromTy->isIncompleteType() && + !ToRefTy->getPointeeType()->isIncompleteType() && + S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) { + BaseToDerivedConversion = 3; + } else if (ToTy->isLValueReferenceType() && !FromExpr->isLValue() && + ToTy.getNonReferenceType().getCanonicalType() == + FromTy.getNonReferenceType().getCanonicalType()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_lvalue) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (unsigned)isObjectArgument << I + 1 + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()); + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + } + + if (BaseToDerivedConversion) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) + << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + if (isa<ObjCObjectPointerType>(CFromTy) && + isa<PointerType>(CToTy)) { + Qualifiers FromQs = CFromTy.getQualifiers(); + Qualifiers ToQs = CToTy.getQualifiers(); + if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second + << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) + << FromTy << ToTy << (unsigned)isObjectArgument << I + 1; + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + } + + if (TakingCandidateAddress && + !checkAddressOfCandidateIsAvailable(S, Cand->Function)) + return; + + // Emit the generic diagnostic and, optionally, add the hints to it. + PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv); + FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy + << ToTy << (unsigned)isObjectArgument << I + 1 + << (unsigned)(Cand->Fix.Kind); + + // If we can fix the conversion, suggest the FixIts. + for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(), + HE = Cand->Fix.Hints.end(); HI != HE; ++HI) + FDiag << *HI; + S.Diag(Fn->getLocation(), FDiag); + + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); +} + +/// Additional arity mismatch diagnosis specific to a function overload +/// candidates. This is not covered by the more general DiagnoseArityMismatch() +/// over a candidate in any candidate set. +static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand, + unsigned NumArgs) { + FunctionDecl *Fn = Cand->Function; + unsigned MinParams = Fn->getMinRequiredArguments(); + + // With invalid overloaded operators, it's possible that we think we + // have an arity mismatch when in fact it looks like we have the + // right number of arguments, because only overloaded operators have + // the weird behavior of overloading member and non-member functions. + // Just don't report anything. + if (Fn->isInvalidDecl() && + Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName) + return true; + + if (NumArgs < MinParams) { + assert((Cand->FailureKind == ovl_fail_too_few_arguments) || + (Cand->FailureKind == ovl_fail_bad_deduction && + Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments)); + } else { + assert((Cand->FailureKind == ovl_fail_too_many_arguments) || + (Cand->FailureKind == ovl_fail_bad_deduction && + Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments)); + } + + return false; +} + +/// General arity mismatch diagnosis over a candidate in a candidate set. +static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D, + unsigned NumFormalArgs) { + assert(isa<FunctionDecl>(D) && + "The templated declaration should at least be a function" + " when diagnosing bad template argument deduction due to too many" + " or too few arguments"); + + FunctionDecl *Fn = cast<FunctionDecl>(D); + + // TODO: treat calls to a missing default constructor as a special case + const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); + unsigned MinParams = Fn->getMinRequiredArguments(); + + // at least / at most / exactly + unsigned mode, modeCount; + if (NumFormalArgs < MinParams) { + if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() || + FnTy->isTemplateVariadic()) + mode = 0; // "at least" + else + mode = 2; // "exactly" + modeCount = MinParams; + } else { + if (MinParams != FnTy->getNumParams()) + mode = 1; // "at most" + else + mode = 2; // "exactly" + modeCount = FnTy->getNumParams(); + } + + std::string Description; + std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair = + ClassifyOverloadCandidate(S, Found, Fn, Description); + + if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName()) + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second + << Description << mode << Fn->getParamDecl(0) << NumFormalArgs; + else + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second + << Description << mode << modeCount << NumFormalArgs; + + MaybeEmitInheritedConstructorNote(S, Found); +} + +/// Arity mismatch diagnosis specific to a function overload candidate. +static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, + unsigned NumFormalArgs) { + if (!CheckArityMismatch(S, Cand, NumFormalArgs)) + DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs); +} + +static TemplateDecl *getDescribedTemplate(Decl *Templated) { + if (TemplateDecl *TD = Templated->getDescribedTemplate()) + return TD; + llvm_unreachable("Unsupported: Getting the described template declaration" + " for bad deduction diagnosis"); +} + +/// Diagnose a failed template-argument deduction. +static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated, + DeductionFailureInfo &DeductionFailure, + unsigned NumArgs, + bool TakingCandidateAddress) { + TemplateParameter Param = DeductionFailure.getTemplateParameter(); + NamedDecl *ParamD; + (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || + (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || + (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); + switch (DeductionFailure.Result) { + case Sema::TDK_Success: + llvm_unreachable("TDK_success while diagnosing bad deduction"); + + case Sema::TDK_Incomplete: { + assert(ParamD && "no parameter found for incomplete deduction result"); + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_incomplete_deduction) + << ParamD->getDeclName(); + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + case Sema::TDK_IncompletePack: { + assert(ParamD && "no parameter found for incomplete deduction result"); + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_incomplete_deduction_pack) + << ParamD->getDeclName() + << (DeductionFailure.getFirstArg()->pack_size() + 1) + << *DeductionFailure.getFirstArg(); + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + case Sema::TDK_Underqualified: { + assert(ParamD && "no parameter found for bad qualifiers deduction result"); + TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD); + + QualType Param = DeductionFailure.getFirstArg()->getAsType(); + + // Param will have been canonicalized, but it should just be a + // qualified version of ParamD, so move the qualifiers to that. + QualifierCollector Qs; + Qs.strip(Param); + QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl()); + assert(S.Context.hasSameType(Param, NonCanonParam)); + + // Arg has also been canonicalized, but there's nothing we can do + // about that. It also doesn't matter as much, because it won't + // have any template parameters in it (because deduction isn't + // done on dependent types). + QualType Arg = DeductionFailure.getSecondArg()->getAsType(); + + S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified) + << ParamD->getDeclName() << Arg << NonCanonParam; + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + case Sema::TDK_Inconsistent: { + assert(ParamD && "no parameter found for inconsistent deduction result"); + int which = 0; + if (isa<TemplateTypeParmDecl>(ParamD)) + which = 0; + else if (isa<NonTypeTemplateParmDecl>(ParamD)) { + // Deduction might have failed because we deduced arguments of two + // different types for a non-type template parameter. + // FIXME: Use a different TDK value for this. + QualType T1 = + DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType(); + QualType T2 = + DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType(); + if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) { + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_inconsistent_deduction_types) + << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1 + << *DeductionFailure.getSecondArg() << T2; + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + which = 1; + } else { + which = 2; + } + + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_inconsistent_deduction) + << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg() + << *DeductionFailure.getSecondArg(); + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + case Sema::TDK_InvalidExplicitArguments: + assert(ParamD && "no parameter found for invalid explicit arguments"); + if (ParamD->getDeclName()) + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_explicit_arg_mismatch_named) + << ParamD->getDeclName(); + else { + int index = 0; + if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD)) + index = TTP->getIndex(); + else if (NonTypeTemplateParmDecl *NTTP + = dyn_cast<NonTypeTemplateParmDecl>(ParamD)) + index = NTTP->getIndex(); + else + index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex(); + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_explicit_arg_mismatch_unnamed) + << (index + 1); + } + MaybeEmitInheritedConstructorNote(S, Found); + return; + + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + DiagnoseArityMismatch(S, Found, Templated, NumArgs); + return; + + case Sema::TDK_InstantiationDepth: + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_instantiation_depth); + MaybeEmitInheritedConstructorNote(S, Found); + return; + + case Sema::TDK_SubstitutionFailure: { + // Format the template argument list into the argument string. + SmallString<128> TemplateArgString; + if (TemplateArgumentList *Args = + DeductionFailure.getTemplateArgumentList()) { + TemplateArgString = " "; + TemplateArgString += S.getTemplateArgumentBindingsText( + getDescribedTemplate(Templated)->getTemplateParameters(), *Args); + } + + // If this candidate was disabled by enable_if, say so. + PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic(); + if (PDiag && PDiag->second.getDiagID() == + diag::err_typename_nested_not_found_enable_if) { + // FIXME: Use the source range of the condition, and the fully-qualified + // name of the enable_if template. These are both present in PDiag. + S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if) + << "'enable_if'" << TemplateArgString; + return; + } + + // We found a specific requirement that disabled the enable_if. + if (PDiag && PDiag->second.getDiagID() == + diag::err_typename_nested_not_found_requirement) { + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_disabled_by_requirement) + << PDiag->second.getStringArg(0) << TemplateArgString; + return; + } + + // Format the SFINAE diagnostic into the argument string. + // FIXME: Add a general mechanism to include a PartialDiagnostic *'s + // formatted message in another diagnostic. + SmallString<128> SFINAEArgString; + SourceRange R; + if (PDiag) { + SFINAEArgString = ": "; + R = SourceRange(PDiag->first, PDiag->first); + PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString); + } + + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_substitution_failure) + << TemplateArgString << SFINAEArgString << R; + MaybeEmitInheritedConstructorNote(S, Found); + return; + } + + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: { + // Format the template argument list into the argument string. + SmallString<128> TemplateArgString; + if (TemplateArgumentList *Args = + DeductionFailure.getTemplateArgumentList()) { + TemplateArgString = " "; + TemplateArgString += S.getTemplateArgumentBindingsText( + getDescribedTemplate(Templated)->getTemplateParameters(), *Args); + } + + S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch) + << (*DeductionFailure.getCallArgIndex() + 1) + << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg() + << TemplateArgString + << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested); + break; + } + + case Sema::TDK_NonDeducedMismatch: { + // FIXME: Provide a source location to indicate what we couldn't match. + TemplateArgument FirstTA = *DeductionFailure.getFirstArg(); + TemplateArgument SecondTA = *DeductionFailure.getSecondArg(); + if (FirstTA.getKind() == TemplateArgument::Template && + SecondTA.getKind() == TemplateArgument::Template) { + TemplateName FirstTN = FirstTA.getAsTemplate(); + TemplateName SecondTN = SecondTA.getAsTemplate(); + if (FirstTN.getKind() == TemplateName::Template && + SecondTN.getKind() == TemplateName::Template) { + if (FirstTN.getAsTemplateDecl()->getName() == + SecondTN.getAsTemplateDecl()->getName()) { + // FIXME: This fixes a bad diagnostic where both templates are named + // the same. This particular case is a bit difficult since: + // 1) It is passed as a string to the diagnostic printer. + // 2) The diagnostic printer only attempts to find a better + // name for types, not decls. + // Ideally, this should folded into the diagnostic printer. + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_non_deduced_mismatch_qualified) + << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl(); + return; + } + } + } + + if (TakingCandidateAddress && isa<FunctionDecl>(Templated) && + !checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated))) + return; + + // FIXME: For generic lambda parameters, check if the function is a lambda + // call operator, and if so, emit a prettier and more informative + // diagnostic that mentions 'auto' and lambda in addition to + // (or instead of?) the canonical template type parameters. + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_non_deduced_mismatch) + << FirstTA << SecondTA; + return; + } + // TODO: diagnose these individually, then kill off + // note_ovl_candidate_bad_deduction, which is uselessly vague. + case Sema::TDK_MiscellaneousDeductionFailure: + S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction); + MaybeEmitInheritedConstructorNote(S, Found); + return; + case Sema::TDK_CUDATargetMismatch: + S.Diag(Templated->getLocation(), + diag::note_cuda_ovl_candidate_target_mismatch); + return; + } +} + +/// Diagnose a failed template-argument deduction, for function calls. +static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, + unsigned NumArgs, + bool TakingCandidateAddress) { + unsigned TDK = Cand->DeductionFailure.Result; + if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) { + if (CheckArityMismatch(S, Cand, NumArgs)) + return; + } + DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern + Cand->DeductionFailure, NumArgs, TakingCandidateAddress); +} + +/// CUDA: diagnose an invalid call across targets. +static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) { + FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext); + FunctionDecl *Callee = Cand->Function; + + Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller), + CalleeTarget = S.IdentifyCUDATarget(Callee); + + std::string FnDesc; + std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair = + ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee, FnDesc); + + S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target) + << (unsigned)FnKindPair.first << (unsigned)ocs_non_template + << FnDesc /* Ignored */ + << CalleeTarget << CallerTarget; + + // This could be an implicit constructor for which we could not infer the + // target due to a collsion. Diagnose that case. + CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee); + if (Meth != nullptr && Meth->isImplicit()) { + CXXRecordDecl *ParentClass = Meth->getParent(); + Sema::CXXSpecialMember CSM; + + switch (FnKindPair.first) { + default: + return; + case oc_implicit_default_constructor: + CSM = Sema::CXXDefaultConstructor; + break; + case oc_implicit_copy_constructor: + CSM = Sema::CXXCopyConstructor; + break; + case oc_implicit_move_constructor: + CSM = Sema::CXXMoveConstructor; + break; + case oc_implicit_copy_assignment: + CSM = Sema::CXXCopyAssignment; + break; + case oc_implicit_move_assignment: + CSM = Sema::CXXMoveAssignment; + break; + }; + + bool ConstRHS = false; + if (Meth->getNumParams()) { + if (const ReferenceType *RT = + Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) { + ConstRHS = RT->getPointeeType().isConstQualified(); + } + } + + S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth, + /* ConstRHS */ ConstRHS, + /* Diagnose */ true); + } +} + +static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) { + FunctionDecl *Callee = Cand->Function; + EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data); + + S.Diag(Callee->getLocation(), + diag::note_ovl_candidate_disabled_by_function_cond_attr) + << Attr->getCond()->getSourceRange() << Attr->getMessage(); +} + +static void DiagnoseOpenCLExtensionDisabled(Sema &S, OverloadCandidate *Cand) { + FunctionDecl *Callee = Cand->Function; + + S.Diag(Callee->getLocation(), + diag::note_ovl_candidate_disabled_by_extension) + << S.getOpenCLExtensionsFromDeclExtMap(Callee); +} + +/// Generates a 'note' diagnostic for an overload candidate. We've +/// already generated a primary error at the call site. +/// +/// It really does need to be a single diagnostic with its caret +/// pointed at the candidate declaration. Yes, this creates some +/// major challenges of technical writing. Yes, this makes pointing +/// out problems with specific arguments quite awkward. It's still +/// better than generating twenty screens of text for every failed +/// overload. +/// +/// It would be great to be able to express per-candidate problems +/// more richly for those diagnostic clients that cared, but we'd +/// still have to be just as careful with the default diagnostics. +static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, + unsigned NumArgs, + bool TakingCandidateAddress) { + FunctionDecl *Fn = Cand->Function; + + // Note deleted candidates, but only if they're viable. + if (Cand->Viable) { + if (Fn->isDeleted() || S.isFunctionConsideredUnavailable(Fn)) { + std::string FnDesc; + std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair = + ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, FnDesc); + + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) + << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc + << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0); + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + // We don't really have anything else to say about viable candidates. + S.NoteOverloadCandidate(Cand->FoundDecl, Fn); + return; + } + + switch (Cand->FailureKind) { + case ovl_fail_too_many_arguments: + case ovl_fail_too_few_arguments: + return DiagnoseArityMismatch(S, Cand, NumArgs); + + case ovl_fail_bad_deduction: + return DiagnoseBadDeduction(S, Cand, NumArgs, + TakingCandidateAddress); + + case ovl_fail_illegal_constructor: { + S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor) + << (Fn->getPrimaryTemplate() ? 1 : 0); + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + } + + case ovl_fail_trivial_conversion: + case ovl_fail_bad_final_conversion: + case ovl_fail_final_conversion_not_exact: + return S.NoteOverloadCandidate(Cand->FoundDecl, Fn); + + case ovl_fail_bad_conversion: { + unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); + for (unsigned N = Cand->Conversions.size(); I != N; ++I) + if (Cand->Conversions[I].isBad()) + return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress); + + // FIXME: this currently happens when we're called from SemaInit + // when user-conversion overload fails. Figure out how to handle + // those conditions and diagnose them well. + return S.NoteOverloadCandidate(Cand->FoundDecl, Fn); + } + + case ovl_fail_bad_target: + return DiagnoseBadTarget(S, Cand); + + case ovl_fail_enable_if: + return DiagnoseFailedEnableIfAttr(S, Cand); + + case ovl_fail_ext_disabled: + return DiagnoseOpenCLExtensionDisabled(S, Cand); + + case ovl_fail_inhctor_slice: + // It's generally not interesting to note copy/move constructors here. + if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor()) + return; + S.Diag(Fn->getLocation(), + diag::note_ovl_candidate_inherited_constructor_slice) + << (Fn->getPrimaryTemplate() ? 1 : 0) + << Fn->getParamDecl(0)->getType()->isRValueReferenceType(); + MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl); + return; + + case ovl_fail_addr_not_available: { + bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function); + (void)Available; + assert(!Available); + break; + } + case ovl_non_default_multiversion_function: + // Do nothing, these should simply be ignored. + break; + } +} + +static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { + // Desugar the type of the surrogate down to a function type, + // retaining as many typedefs as possible while still showing + // the function type (and, therefore, its parameter types). + QualType FnType = Cand->Surrogate->getConversionType(); + bool isLValueReference = false; + bool isRValueReference = false; + bool isPointer = false; + if (const LValueReferenceType *FnTypeRef = + FnType->getAs<LValueReferenceType>()) { + FnType = FnTypeRef->getPointeeType(); + isLValueReference = true; + } else if (const RValueReferenceType *FnTypeRef = + FnType->getAs<RValueReferenceType>()) { + FnType = FnTypeRef->getPointeeType(); + isRValueReference = true; + } + if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { + FnType = FnTypePtr->getPointeeType(); + isPointer = true; + } + // Desugar down to a function type. + FnType = QualType(FnType->getAs<FunctionType>(), 0); + // Reconstruct the pointer/reference as appropriate. + if (isPointer) FnType = S.Context.getPointerType(FnType); + if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); + if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); + + S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) + << FnType; +} + +static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc, + SourceLocation OpLoc, + OverloadCandidate *Cand) { + assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); + std::string TypeStr("operator"); + TypeStr += Opc; + TypeStr += "("; + TypeStr += Cand->BuiltinParamTypes[0].getAsString(); + if (Cand->Conversions.size() == 1) { + TypeStr += ")"; + S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; + } else { + TypeStr += ", "; + TypeStr += Cand->BuiltinParamTypes[1].getAsString(); + TypeStr += ")"; + S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; + } +} + +static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, + OverloadCandidate *Cand) { + for (const ImplicitConversionSequence &ICS : Cand->Conversions) { + if (ICS.isBad()) break; // all meaningless after first invalid + if (!ICS.isAmbiguous()) continue; + + ICS.DiagnoseAmbiguousConversion( + S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion)); + } +} + +static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { + if (Cand->Function) + return Cand->Function->getLocation(); + if (Cand->IsSurrogate) + return Cand->Surrogate->getLocation(); + return SourceLocation(); +} + +static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) { + switch ((Sema::TemplateDeductionResult)DFI.Result) { + case Sema::TDK_Success: + case Sema::TDK_NonDependentConversionFailure: + llvm_unreachable("non-deduction failure while diagnosing bad deduction"); + + case Sema::TDK_Invalid: + case Sema::TDK_Incomplete: + case Sema::TDK_IncompletePack: + return 1; + + case Sema::TDK_Underqualified: + case Sema::TDK_Inconsistent: + return 2; + + case Sema::TDK_SubstitutionFailure: + case Sema::TDK_DeducedMismatch: + case Sema::TDK_DeducedMismatchNested: + case Sema::TDK_NonDeducedMismatch: + case Sema::TDK_MiscellaneousDeductionFailure: + case Sema::TDK_CUDATargetMismatch: + return 3; + + case Sema::TDK_InstantiationDepth: + return 4; + + case Sema::TDK_InvalidExplicitArguments: + return 5; + + case Sema::TDK_TooManyArguments: + case Sema::TDK_TooFewArguments: + return 6; + } + llvm_unreachable("Unhandled deduction result"); +} + +namespace { +struct CompareOverloadCandidatesForDisplay { + Sema &S; + SourceLocation Loc; + size_t NumArgs; + OverloadCandidateSet::CandidateSetKind CSK; + + CompareOverloadCandidatesForDisplay( + Sema &S, SourceLocation Loc, size_t NArgs, + OverloadCandidateSet::CandidateSetKind CSK) + : S(S), NumArgs(NArgs), CSK(CSK) {} + + bool operator()(const OverloadCandidate *L, + const OverloadCandidate *R) { + // Fast-path this check. + if (L == R) return false; + + // Order first by viability. + if (L->Viable) { + if (!R->Viable) return true; + + // TODO: introduce a tri-valued comparison for overload + // candidates. Would be more worthwhile if we had a sort + // that could exploit it. + if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK)) + return true; + if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK)) + return false; + } else if (R->Viable) + return false; + + assert(L->Viable == R->Viable); + + // Criteria by which we can sort non-viable candidates: + if (!L->Viable) { + // 1. Arity mismatches come after other candidates. + if (L->FailureKind == ovl_fail_too_many_arguments || + L->FailureKind == ovl_fail_too_few_arguments) { + if (R->FailureKind == ovl_fail_too_many_arguments || + R->FailureKind == ovl_fail_too_few_arguments) { + int LDist = std::abs((int)L->getNumParams() - (int)NumArgs); + int RDist = std::abs((int)R->getNumParams() - (int)NumArgs); + if (LDist == RDist) { + if (L->FailureKind == R->FailureKind) + // Sort non-surrogates before surrogates. + return !L->IsSurrogate && R->IsSurrogate; + // Sort candidates requiring fewer parameters than there were + // arguments given after candidates requiring more parameters + // than there were arguments given. + return L->FailureKind == ovl_fail_too_many_arguments; + } + return LDist < RDist; + } + return false; + } + if (R->FailureKind == ovl_fail_too_many_arguments || + R->FailureKind == ovl_fail_too_few_arguments) + return true; + + // 2. Bad conversions come first and are ordered by the number + // of bad conversions and quality of good conversions. + if (L->FailureKind == ovl_fail_bad_conversion) { + if (R->FailureKind != ovl_fail_bad_conversion) + return true; + + // The conversion that can be fixed with a smaller number of changes, + // comes first. + unsigned numLFixes = L->Fix.NumConversionsFixed; + unsigned numRFixes = R->Fix.NumConversionsFixed; + numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes; + numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes; + if (numLFixes != numRFixes) { + return numLFixes < numRFixes; + } + + // If there's any ordering between the defined conversions... + // FIXME: this might not be transitive. + assert(L->Conversions.size() == R->Conversions.size()); + + int leftBetter = 0; + unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); + for (unsigned E = L->Conversions.size(); I != E; ++I) { + switch (CompareImplicitConversionSequences(S, Loc, + L->Conversions[I], + R->Conversions[I])) { + case ImplicitConversionSequence::Better: + leftBetter++; + break; + + case ImplicitConversionSequence::Worse: + leftBetter--; + break; + + case ImplicitConversionSequence::Indistinguishable: + break; + } + } + if (leftBetter > 0) return true; + if (leftBetter < 0) return false; + + } else if (R->FailureKind == ovl_fail_bad_conversion) + return false; + + if (L->FailureKind == ovl_fail_bad_deduction) { + if (R->FailureKind != ovl_fail_bad_deduction) + return true; + + if (L->DeductionFailure.Result != R->DeductionFailure.Result) + return RankDeductionFailure(L->DeductionFailure) + < RankDeductionFailure(R->DeductionFailure); + } else if (R->FailureKind == ovl_fail_bad_deduction) + return false; + + // TODO: others? + } + + // Sort everything else by location. + SourceLocation LLoc = GetLocationForCandidate(L); + SourceLocation RLoc = GetLocationForCandidate(R); + + // Put candidates without locations (e.g. builtins) at the end. + if (LLoc.isInvalid()) return false; + if (RLoc.isInvalid()) return true; + + return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); + } +}; +} + +/// CompleteNonViableCandidate - Normally, overload resolution only +/// computes up to the first bad conversion. Produces the FixIt set if +/// possible. +static void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, + ArrayRef<Expr *> Args) { + assert(!Cand->Viable); + + // Don't do anything on failures other than bad conversion. + if (Cand->FailureKind != ovl_fail_bad_conversion) return; + + // We only want the FixIts if all the arguments can be corrected. + bool Unfixable = false; + // Use a implicit copy initialization to check conversion fixes. + Cand->Fix.setConversionChecker(TryCopyInitialization); + + // Attempt to fix the bad conversion. + unsigned ConvCount = Cand->Conversions.size(); + for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/; + ++ConvIdx) { + assert(ConvIdx != ConvCount && "no bad conversion in candidate"); + if (Cand->Conversions[ConvIdx].isInitialized() && + Cand->Conversions[ConvIdx].isBad()) { + Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S); + break; + } + } + + // FIXME: this should probably be preserved from the overload + // operation somehow. + bool SuppressUserConversions = false; + + unsigned ConvIdx = 0; + ArrayRef<QualType> ParamTypes; + + if (Cand->IsSurrogate) { + QualType ConvType + = Cand->Surrogate->getConversionType().getNonReferenceType(); + if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) + ConvType = ConvPtrType->getPointeeType(); + ParamTypes = ConvType->getAs<FunctionProtoType>()->getParamTypes(); + // Conversion 0 is 'this', which doesn't have a corresponding argument. + ConvIdx = 1; + } else if (Cand->Function) { + ParamTypes = + Cand->Function->getType()->getAs<FunctionProtoType>()->getParamTypes(); + if (isa<CXXMethodDecl>(Cand->Function) && + !isa<CXXConstructorDecl>(Cand->Function)) { + // Conversion 0 is 'this', which doesn't have a corresponding argument. + ConvIdx = 1; + } + } else { + // Builtin operator. + assert(ConvCount <= 3); + ParamTypes = Cand->BuiltinParamTypes; + } + + // Fill in the rest of the conversions. + for (unsigned ArgIdx = 0; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { + if (Cand->Conversions[ConvIdx].isInitialized()) { + // We've already checked this conversion. + } else if (ArgIdx < ParamTypes.size()) { + if (ParamTypes[ArgIdx]->isDependentType()) + Cand->Conversions[ConvIdx].setAsIdentityConversion( + Args[ArgIdx]->getType()); + else { + Cand->Conversions[ConvIdx] = + TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ArgIdx], + SuppressUserConversions, + /*InOverloadResolution=*/true, + /*AllowObjCWritebackConversion=*/ + S.getLangOpts().ObjCAutoRefCount); + // Store the FixIt in the candidate if it exists. + if (!Unfixable && Cand->Conversions[ConvIdx].isBad()) + Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S); + } + } else + Cand->Conversions[ConvIdx].setEllipsis(); + } +} + +/// When overload resolution fails, prints diagnostic messages containing the +/// candidates in the candidate set. +void OverloadCandidateSet::NoteCandidates( + Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args, + StringRef Opc, SourceLocation OpLoc, + llvm::function_ref<bool(OverloadCandidate &)> Filter) { + // Sort the candidates by viability and position. Sorting directly would + // be prohibitive, so we make a set of pointers and sort those. + SmallVector<OverloadCandidate*, 32> Cands; + if (OCD == OCD_AllCandidates) Cands.reserve(size()); + for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) { + if (!Filter(*Cand)) + continue; + if (Cand->Viable) + Cands.push_back(Cand); + else if (OCD == OCD_AllCandidates) { + CompleteNonViableCandidate(S, Cand, Args); + if (Cand->Function || Cand->IsSurrogate) + Cands.push_back(Cand); + // Otherwise, this a non-viable builtin candidate. We do not, in general, + // want to list every possible builtin candidate. + } + } + + std::stable_sort(Cands.begin(), Cands.end(), + CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind)); + + bool ReportedAmbiguousConversions = false; + + SmallVectorImpl<OverloadCandidate*>::iterator I, E; + const OverloadsShown ShowOverloads = S.Diags.getShowOverloads(); + unsigned CandsShown = 0; + for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { + OverloadCandidate *Cand = *I; + + // Set an arbitrary limit on the number of candidate functions we'll spam + // the user with. FIXME: This limit should depend on details of the + // candidate list. + if (CandsShown >= 4 && ShowOverloads == Ovl_Best) { + break; + } + ++CandsShown; + + if (Cand->Function) + NoteFunctionCandidate(S, Cand, Args.size(), + /*TakingCandidateAddress=*/false); + else if (Cand->IsSurrogate) + NoteSurrogateCandidate(S, Cand); + else { + assert(Cand->Viable && + "Non-viable built-in candidates are not added to Cands."); + // Generally we only see ambiguities including viable builtin + // operators if overload resolution got screwed up by an + // ambiguous user-defined conversion. + // + // FIXME: It's quite possible for different conversions to see + // different ambiguities, though. + if (!ReportedAmbiguousConversions) { + NoteAmbiguousUserConversions(S, OpLoc, Cand); + ReportedAmbiguousConversions = true; + } + + // If this is a viable builtin, print it. + NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand); + } + } + + if (I != E) + S.Diag(OpLoc, diag::note_ovl_too_many_candidates) << int(E - I); +} + +static SourceLocation +GetLocationForCandidate(const TemplateSpecCandidate *Cand) { + return Cand->Specialization ? Cand->Specialization->getLocation() + : SourceLocation(); +} + +namespace { +struct CompareTemplateSpecCandidatesForDisplay { + Sema &S; + CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {} + + bool operator()(const TemplateSpecCandidate *L, + const TemplateSpecCandidate *R) { + // Fast-path this check. + if (L == R) + return false; + + // Assuming that both candidates are not matches... + + // Sort by the ranking of deduction failures. + if (L->DeductionFailure.Result != R->DeductionFailure.Result) + return RankDeductionFailure(L->DeductionFailure) < + RankDeductionFailure(R->DeductionFailure); + + // Sort everything else by location. + SourceLocation LLoc = GetLocationForCandidate(L); + SourceLocation RLoc = GetLocationForCandidate(R); + + // Put candidates without locations (e.g. builtins) at the end. + if (LLoc.isInvalid()) + return false; + if (RLoc.isInvalid()) + return true; + + return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); + } +}; +} + +/// Diagnose a template argument deduction failure. +/// We are treating these failures as overload failures due to bad +/// deductions. +void TemplateSpecCandidate::NoteDeductionFailure(Sema &S, + bool ForTakingAddress) { + DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern + DeductionFailure, /*NumArgs=*/0, ForTakingAddress); +} + +void TemplateSpecCandidateSet::destroyCandidates() { + for (iterator i = begin(), e = end(); i != e; ++i) { + i->DeductionFailure.Destroy(); + } +} + +void TemplateSpecCandidateSet::clear() { + destroyCandidates(); + Candidates.clear(); +} + +/// NoteCandidates - When no template specialization match is found, prints +/// diagnostic messages containing the non-matching specializations that form +/// the candidate set. +/// This is analoguous to OverloadCandidateSet::NoteCandidates() with +/// OCD == OCD_AllCandidates and Cand->Viable == false. +void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) { + // Sort the candidates by position (assuming no candidate is a match). + // Sorting directly would be prohibitive, so we make a set of pointers + // and sort those. + SmallVector<TemplateSpecCandidate *, 32> Cands; + Cands.reserve(size()); + for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) { + if (Cand->Specialization) + Cands.push_back(Cand); + // Otherwise, this is a non-matching builtin candidate. We do not, + // in general, want to list every possible builtin candidate. + } + + llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S)); + + // FIXME: Perhaps rename OverloadsShown and getShowOverloads() + // for generalization purposes (?). + const OverloadsShown ShowOverloads = S.Diags.getShowOverloads(); + + SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E; + unsigned CandsShown = 0; + for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { + TemplateSpecCandidate *Cand = *I; + + // Set an arbitrary limit on the number of candidates we'll spam + // the user with. FIXME: This limit should depend on details of the + // candidate list. + if (CandsShown >= 4 && ShowOverloads == Ovl_Best) + break; + ++CandsShown; + + assert(Cand->Specialization && + "Non-matching built-in candidates are not added to Cands."); + Cand->NoteDeductionFailure(S, ForTakingAddress); + } + + if (I != E) + S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I); +} + +// [PossiblyAFunctionType] --> [Return] +// NonFunctionType --> NonFunctionType +// R (A) --> R(A) +// R (*)(A) --> R (A) +// R (&)(A) --> R (A) +// R (S::*)(A) --> R (A) +QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) { + QualType Ret = PossiblyAFunctionType; + if (const PointerType *ToTypePtr = + PossiblyAFunctionType->getAs<PointerType>()) + Ret = ToTypePtr->getPointeeType(); + else if (const ReferenceType *ToTypeRef = + PossiblyAFunctionType->getAs<ReferenceType>()) + Ret = ToTypeRef->getPointeeType(); + else if (const MemberPointerType *MemTypePtr = + PossiblyAFunctionType->getAs<MemberPointerType>()) + Ret = MemTypePtr->getPointeeType(); + Ret = + Context.getCanonicalType(Ret).getUnqualifiedType(); + return Ret; +} + +static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc, + bool Complain = true) { + if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() && + S.DeduceReturnType(FD, Loc, Complain)) + return true; + + auto *FPT = FD->getType()->castAs<FunctionProtoType>(); + if (S.getLangOpts().CPlusPlus17 && + isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) && + !S.ResolveExceptionSpec(Loc, FPT)) + return true; + + return false; +} + +namespace { +// A helper class to help with address of function resolution +// - allows us to avoid passing around all those ugly parameters +class AddressOfFunctionResolver { + Sema& S; + Expr* SourceExpr; + const QualType& TargetType; + QualType TargetFunctionType; // Extracted function type from target type + + bool Complain; + //DeclAccessPair& ResultFunctionAccessPair; + ASTContext& Context; + + bool TargetTypeIsNonStaticMemberFunction; + bool FoundNonTemplateFunction; + bool StaticMemberFunctionFromBoundPointer; + bool HasComplained; + + OverloadExpr::FindResult OvlExprInfo; + OverloadExpr *OvlExpr; + TemplateArgumentListInfo OvlExplicitTemplateArgs; + SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; + TemplateSpecCandidateSet FailedCandidates; + +public: + AddressOfFunctionResolver(Sema &S, Expr *SourceExpr, + const QualType &TargetType, bool Complain) + : S(S), SourceExpr(SourceExpr), TargetType(TargetType), + Complain(Complain), Context(S.getASTContext()), + TargetTypeIsNonStaticMemberFunction( + !!TargetType->getAs<MemberPointerType>()), + FoundNonTemplateFunction(false), + StaticMemberFunctionFromBoundPointer(false), + HasComplained(false), + OvlExprInfo(OverloadExpr::find(SourceExpr)), + OvlExpr(OvlExprInfo.Expression), + FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) { + ExtractUnqualifiedFunctionTypeFromTargetType(); + + if (TargetFunctionType->isFunctionType()) { + if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr)) + if (!UME->isImplicitAccess() && + !S.ResolveSingleFunctionTemplateSpecialization(UME)) + StaticMemberFunctionFromBoundPointer = true; + } else if (OvlExpr->hasExplicitTemplateArgs()) { + DeclAccessPair dap; + if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization( + OvlExpr, false, &dap)) { + if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) + if (!Method->isStatic()) { + // If the target type is a non-function type and the function found + // is a non-static member function, pretend as if that was the + // target, it's the only possible type to end up with. + TargetTypeIsNonStaticMemberFunction = true; + + // And skip adding the function if its not in the proper form. + // We'll diagnose this due to an empty set of functions. + if (!OvlExprInfo.HasFormOfMemberPointer) + return; + } + + Matches.push_back(std::make_pair(dap, Fn)); + } + return; + } + + if (OvlExpr->hasExplicitTemplateArgs()) + OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs); + + if (FindAllFunctionsThatMatchTargetTypeExactly()) { + // C++ [over.over]p4: + // If more than one function is selected, [...] + if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) { + if (FoundNonTemplateFunction) + EliminateAllTemplateMatches(); + else + EliminateAllExceptMostSpecializedTemplate(); + } + } + + if (S.getLangOpts().CUDA && Matches.size() > 1) + EliminateSuboptimalCudaMatches(); + } + + bool hasComplained() const { return HasComplained; } + +private: + bool candidateHasExactlyCorrectType(const FunctionDecl *FD) { + QualType Discard; + return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) || + S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard); + } + + /// \return true if A is considered a better overload candidate for the + /// desired type than B. + bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) { + // If A doesn't have exactly the correct type, we don't want to classify it + // as "better" than anything else. This way, the user is required to + // disambiguate for us if there are multiple candidates and no exact match. + return candidateHasExactlyCorrectType(A) && + (!candidateHasExactlyCorrectType(B) || + compareEnableIfAttrs(S, A, B) == Comparison::Better); + } + + /// \return true if we were able to eliminate all but one overload candidate, + /// false otherwise. + bool eliminiateSuboptimalOverloadCandidates() { + // Same algorithm as overload resolution -- one pass to pick the "best", + // another pass to be sure that nothing is better than the best. + auto Best = Matches.begin(); + for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I) + if (isBetterCandidate(I->second, Best->second)) + Best = I; + + const FunctionDecl *BestFn = Best->second; + auto IsBestOrInferiorToBest = [this, BestFn]( + const std::pair<DeclAccessPair, FunctionDecl *> &Pair) { + return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second); + }; + + // Note: We explicitly leave Matches unmodified if there isn't a clear best + // option, so we can potentially give the user a better error + if (!llvm::all_of(Matches, IsBestOrInferiorToBest)) + return false; + Matches[0] = *Best; + Matches.resize(1); + return true; + } + + bool isTargetTypeAFunction() const { + return TargetFunctionType->isFunctionType(); + } + + // [ToType] [Return] + + // R (*)(A) --> R (A), IsNonStaticMemberFunction = false + // R (&)(A) --> R (A), IsNonStaticMemberFunction = false + // R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true + void inline ExtractUnqualifiedFunctionTypeFromTargetType() { + TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType); + } + + // return true if any matching specializations were found + bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate, + const DeclAccessPair& CurAccessFunPair) { + if (CXXMethodDecl *Method + = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { + // Skip non-static function templates when converting to pointer, and + // static when converting to member pointer. + if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction) + return false; + } + else if (TargetTypeIsNonStaticMemberFunction) + return false; + + // C++ [over.over]p2: + // If the name is a function template, template argument deduction is + // done (14.8.2.2), and if the argument deduction succeeds, the + // resulting template argument list is used to generate a single + // function template specialization, which is added to the set of + // overloaded functions considered. + FunctionDecl *Specialization = nullptr; + TemplateDeductionInfo Info(FailedCandidates.getLocation()); + if (Sema::TemplateDeductionResult Result + = S.DeduceTemplateArguments(FunctionTemplate, + &OvlExplicitTemplateArgs, + TargetFunctionType, Specialization, + Info, /*IsAddressOfFunction*/true)) { + // Make a note of the failed deduction for diagnostics. + FailedCandidates.addCandidate() + .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(), + MakeDeductionFailureInfo(Context, Result, Info)); + return false; + } + + // Template argument deduction ensures that we have an exact match or + // compatible pointer-to-function arguments that would be adjusted by ICS. + // This function template specicalization works. + assert(S.isSameOrCompatibleFunctionType( + Context.getCanonicalType(Specialization->getType()), + Context.getCanonicalType(TargetFunctionType))); + + if (!S.checkAddressOfFunctionIsAvailable(Specialization)) + return false; + + Matches.push_back(std::make_pair(CurAccessFunPair, Specialization)); + return true; + } + + bool AddMatchingNonTemplateFunction(NamedDecl* Fn, + const DeclAccessPair& CurAccessFunPair) { + if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { + // Skip non-static functions when converting to pointer, and static + // when converting to member pointer. + if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction) + return false; + } + else if (TargetTypeIsNonStaticMemberFunction) + return false; + + if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { + if (S.getLangOpts().CUDA) + if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext)) + if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl)) + return false; + if (FunDecl->isMultiVersion()) { + const auto *TA = FunDecl->getAttr<TargetAttr>(); + if (TA && !TA->isDefaultVersion()) + return false; + } + + // If any candidate has a placeholder return type, trigger its deduction + // now. + if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(), + Complain)) { + HasComplained |= Complain; + return false; + } + + if (!S.checkAddressOfFunctionIsAvailable(FunDecl)) + return false; + + // If we're in C, we need to support types that aren't exactly identical. + if (!S.getLangOpts().CPlusPlus || + candidateHasExactlyCorrectType(FunDecl)) { + Matches.push_back(std::make_pair( + CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); + FoundNonTemplateFunction = true; + return true; + } + } + + return false; + } + + bool FindAllFunctionsThatMatchTargetTypeExactly() { + bool Ret = false; + + // If the overload expression doesn't have the form of a pointer to + // member, don't try to convert it to a pointer-to-member type. + if (IsInvalidFormOfPointerToMemberFunction()) + return false; + + for (UnresolvedSetIterator I = OvlExpr->decls_begin(), + E = OvlExpr->decls_end(); + I != E; ++I) { + // Look through any using declarations to find the underlying function. + NamedDecl *Fn = (*I)->getUnderlyingDecl(); + + // C++ [over.over]p3: + // Non-member functions and static member functions match + // targets of type "pointer-to-function" or "reference-to-function." + // Nonstatic member functions match targets of + // type "pointer-to-member-function." + // Note that according to DR 247, the containing class does not matter. + if (FunctionTemplateDecl *FunctionTemplate + = dyn_cast<FunctionTemplateDecl>(Fn)) { + if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair())) + Ret = true; + } + // If we have explicit template arguments supplied, skip non-templates. + else if (!OvlExpr->hasExplicitTemplateArgs() && + AddMatchingNonTemplateFunction(Fn, I.getPair())) + Ret = true; + } + assert(Ret || Matches.empty()); + return Ret; + } + + void EliminateAllExceptMostSpecializedTemplate() { + // [...] and any given function template specialization F1 is + // eliminated if the set contains a second function template + // specialization whose function template is more specialized + // than the function template of F1 according to the partial + // ordering rules of 14.5.5.2. + + // The algorithm specified above is quadratic. We instead use a + // two-pass algorithm (similar to the one used to identify the + // best viable function in an overload set) that identifies the + // best function template (if it exists). + + UnresolvedSet<4> MatchesCopy; // TODO: avoid! + for (unsigned I = 0, E = Matches.size(); I != E; ++I) + MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); + + // TODO: It looks like FailedCandidates does not serve much purpose + // here, since the no_viable diagnostic has index 0. + UnresolvedSetIterator Result = S.getMostSpecialized( + MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates, + SourceExpr->getBeginLoc(), S.PDiag(), + S.PDiag(diag::err_addr_ovl_ambiguous) + << Matches[0].second->getDeclName(), + S.PDiag(diag::note_ovl_candidate) + << (unsigned)oc_function << (unsigned)ocs_described_template, + Complain, TargetFunctionType); + + if (Result != MatchesCopy.end()) { + // Make it the first and only element + Matches[0].first = Matches[Result - MatchesCopy.begin()].first; + Matches[0].second = cast<FunctionDecl>(*Result); + Matches.resize(1); + } else + HasComplained |= Complain; + } + + void EliminateAllTemplateMatches() { + // [...] any function template specializations in the set are + // eliminated if the set also contains a non-template function, [...] + for (unsigned I = 0, N = Matches.size(); I != N; ) { + if (Matches[I].second->getPrimaryTemplate() == nullptr) + ++I; + else { + Matches[I] = Matches[--N]; + Matches.resize(N); + } + } + } + + void EliminateSuboptimalCudaMatches() { + S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches); + } + +public: + void ComplainNoMatchesFound() const { + assert(Matches.empty()); + S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable) + << OvlExpr->getName() << TargetFunctionType + << OvlExpr->getSourceRange(); + if (FailedCandidates.empty()) + S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType, + /*TakingAddress=*/true); + else { + // We have some deduction failure messages. Use them to diagnose + // the function templates, and diagnose the non-template candidates + // normally. + for (UnresolvedSetIterator I = OvlExpr->decls_begin(), + IEnd = OvlExpr->decls_end(); + I != IEnd; ++I) + if (FunctionDecl *Fun = + dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) + if (!functionHasPassObjectSizeParams(Fun)) + S.NoteOverloadCandidate(*I, Fun, TargetFunctionType, + /*TakingAddress=*/true); + FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc()); + } + } + + bool IsInvalidFormOfPointerToMemberFunction() const { + return TargetTypeIsNonStaticMemberFunction && + !OvlExprInfo.HasFormOfMemberPointer; + } + + void ComplainIsInvalidFormOfPointerToMemberFunction() const { + // TODO: Should we condition this on whether any functions might + // have matched, or is it more appropriate to do that in callers? + // TODO: a fixit wouldn't hurt. + S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier) + << TargetType << OvlExpr->getSourceRange(); + } + + bool IsStaticMemberFunctionFromBoundPointer() const { + return StaticMemberFunctionFromBoundPointer; + } + + void ComplainIsStaticMemberFunctionFromBoundPointer() const { + S.Diag(OvlExpr->getBeginLoc(), + diag::err_invalid_form_pointer_member_function) + << OvlExpr->getSourceRange(); + } + + void ComplainOfInvalidConversion() const { + S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref) + << OvlExpr->getName() << TargetType; + } + + void ComplainMultipleMatchesFound() const { + assert(Matches.size() > 1); + S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous) + << OvlExpr->getName() << OvlExpr->getSourceRange(); + S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType, + /*TakingAddress=*/true); + } + + bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); } + + int getNumMatches() const { return Matches.size(); } + + FunctionDecl* getMatchingFunctionDecl() const { + if (Matches.size() != 1) return nullptr; + return Matches[0].second; + } + + const DeclAccessPair* getMatchingFunctionAccessPair() const { + if (Matches.size() != 1) return nullptr; + return &Matches[0].first; + } +}; +} + +/// ResolveAddressOfOverloadedFunction - Try to resolve the address of +/// an overloaded function (C++ [over.over]), where @p From is an +/// expression with overloaded function type and @p ToType is the type +/// we're trying to resolve to. For example: +/// +/// @code +/// int f(double); +/// int f(int); +/// +/// int (*pfd)(double) = f; // selects f(double) +/// @endcode +/// +/// This routine returns the resulting FunctionDecl if it could be +/// resolved, and NULL otherwise. When @p Complain is true, this +/// routine will emit diagnostics if there is an error. +FunctionDecl * +Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr, + QualType TargetType, + bool Complain, + DeclAccessPair &FoundResult, + bool *pHadMultipleCandidates) { + assert(AddressOfExpr->getType() == Context.OverloadTy); + + AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType, + Complain); + int NumMatches = Resolver.getNumMatches(); + FunctionDecl *Fn = nullptr; + bool ShouldComplain = Complain && !Resolver.hasComplained(); + if (NumMatches == 0 && ShouldComplain) { + if (Resolver.IsInvalidFormOfPointerToMemberFunction()) + Resolver.ComplainIsInvalidFormOfPointerToMemberFunction(); + else + Resolver.ComplainNoMatchesFound(); + } + else if (NumMatches > 1 && ShouldComplain) + Resolver.ComplainMultipleMatchesFound(); + else if (NumMatches == 1) { + Fn = Resolver.getMatchingFunctionDecl(); + assert(Fn); + if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>()) + ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT); + FoundResult = *Resolver.getMatchingFunctionAccessPair(); + if (Complain) { + if (Resolver.IsStaticMemberFunctionFromBoundPointer()) + Resolver.ComplainIsStaticMemberFunctionFromBoundPointer(); + else + CheckAddressOfMemberAccess(AddressOfExpr, FoundResult); + } + } + + if (pHadMultipleCandidates) + *pHadMultipleCandidates = Resolver.hadMultipleCandidates(); + return Fn; +} + +/// Given an expression that refers to an overloaded function, try to +/// resolve that function to a single function that can have its address taken. +/// This will modify `Pair` iff it returns non-null. +/// +/// This routine can only realistically succeed if all but one candidates in the +/// overload set for SrcExpr cannot have their addresses taken. +FunctionDecl * +Sema::resolveAddressOfOnlyViableOverloadCandidate(Expr *E, + DeclAccessPair &Pair) { + OverloadExpr::FindResult R = OverloadExpr::find(E); + OverloadExpr *Ovl = R.Expression; + FunctionDecl *Result = nullptr; + DeclAccessPair DAP; + // Don't use the AddressOfResolver because we're specifically looking for + // cases where we have one overload candidate that lacks + // enable_if/pass_object_size/... + for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) { + auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl()); + if (!FD) + return nullptr; + + if (!checkAddressOfFunctionIsAvailable(FD)) + continue; + + // We have more than one result; quit. + if (Result) + return nullptr; + DAP = I.getPair(); + Result = FD; + } + + if (Result) + Pair = DAP; + return Result; +} + +/// Given an overloaded function, tries to turn it into a non-overloaded +/// function reference using resolveAddressOfOnlyViableOverloadCandidate. This +/// will perform access checks, diagnose the use of the resultant decl, and, if +/// requested, potentially perform a function-to-pointer decay. +/// +/// Returns false if resolveAddressOfOnlyViableOverloadCandidate fails. +/// Otherwise, returns true. This may emit diagnostics and return true. +bool Sema::resolveAndFixAddressOfOnlyViableOverloadCandidate( + ExprResult &SrcExpr, bool DoFunctionPointerConverion) { + Expr *E = SrcExpr.get(); + assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload"); + + DeclAccessPair DAP; + FunctionDecl *Found = resolveAddressOfOnlyViableOverloadCandidate(E, DAP); + if (!Found || Found->isCPUDispatchMultiVersion() || + Found->isCPUSpecificMultiVersion()) + return false; + + // Emitting multiple diagnostics for a function that is both inaccessible and + // unavailable is consistent with our behavior elsewhere. So, always check + // for both. + DiagnoseUseOfDecl(Found, E->getExprLoc()); + CheckAddressOfMemberAccess(E, DAP); + Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found); + if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType()) + SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false); + else + SrcExpr = Fixed; + return true; +} + +/// Given an expression that refers to an overloaded function, try to +/// resolve that overloaded function expression down to a single function. +/// +/// This routine can only resolve template-ids that refer to a single function +/// template, where that template-id refers to a single template whose template +/// arguments are either provided by the template-id or have defaults, +/// as described in C++0x [temp.arg.explicit]p3. +/// +/// If no template-ids are found, no diagnostics are emitted and NULL is +/// returned. +FunctionDecl * +Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl, + bool Complain, + DeclAccessPair *FoundResult) { + // C++ [over.over]p1: + // [...] [Note: any redundant set of parentheses surrounding the + // overloaded function name is ignored (5.1). ] + // C++ [over.over]p1: + // [...] The overloaded function name can be preceded by the & + // operator. + + // If we didn't actually find any template-ids, we're done. + if (!ovl->hasExplicitTemplateArgs()) + return nullptr; + + TemplateArgumentListInfo ExplicitTemplateArgs; + ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs); + TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc()); + + // Look through all of the overloaded functions, searching for one + // whose type matches exactly. + FunctionDecl *Matched = nullptr; + for (UnresolvedSetIterator I = ovl->decls_begin(), + E = ovl->decls_end(); I != E; ++I) { + // C++0x [temp.arg.explicit]p3: + // [...] In contexts where deduction is done and fails, or in contexts + // where deduction is not done, if a template argument list is + // specified and it, along with any default template arguments, + // identifies a single function template specialization, then the + // template-id is an lvalue for the function template specialization. + FunctionTemplateDecl *FunctionTemplate + = cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()); + + // C++ [over.over]p2: + // If the name is a function template, template argument deduction is + // done (14.8.2.2), and if the argument deduction succeeds, the + // resulting template argument list is used to generate a single + // function template specialization, which is added to the set of + // overloaded functions considered. + FunctionDecl *Specialization = nullptr; + TemplateDeductionInfo Info(FailedCandidates.getLocation()); + if (TemplateDeductionResult Result + = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, + Specialization, Info, + /*IsAddressOfFunction*/true)) { + // Make a note of the failed deduction for diagnostics. + // TODO: Actually use the failed-deduction info? + FailedCandidates.addCandidate() + .set(I.getPair(), FunctionTemplate->getTemplatedDecl(), + MakeDeductionFailureInfo(Context, Result, Info)); + continue; + } + + assert(Specialization && "no specialization and no error?"); + + // Multiple matches; we can't resolve to a single declaration. + if (Matched) { + if (Complain) { + Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous) + << ovl->getName(); + NoteAllOverloadCandidates(ovl); + } + return nullptr; + } + + Matched = Specialization; + if (FoundResult) *FoundResult = I.getPair(); + } + + if (Matched && + completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain)) + return nullptr; + + return Matched; +} + +// Resolve and fix an overloaded expression that can be resolved +// because it identifies a single function template specialization. +// +// Last three arguments should only be supplied if Complain = true +// +// Return true if it was logically possible to so resolve the +// expression, regardless of whether or not it succeeded. Always +// returns true if 'complain' is set. +bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization( + ExprResult &SrcExpr, bool doFunctionPointerConverion, + bool complain, SourceRange OpRangeForComplaining, + QualType DestTypeForComplaining, + unsigned DiagIDForComplaining) { + assert(SrcExpr.get()->getType() == Context.OverloadTy); + + OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get()); + + DeclAccessPair found; + ExprResult SingleFunctionExpression; + if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization( + ovl.Expression, /*complain*/ false, &found)) { + if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) { + SrcExpr = ExprError(); + return true; + } + + // It is only correct to resolve to an instance method if we're + // resolving a form that's permitted to be a pointer to member. + // Otherwise we'll end up making a bound member expression, which + // is illegal in all the contexts we resolve like this. + if (!ovl.HasFormOfMemberPointer && + isa<CXXMethodDecl>(fn) && + cast<CXXMethodDecl>(fn)->isInstance()) { + if (!complain) return false; + + Diag(ovl.Expression->getExprLoc(), + diag::err_bound_member_function) + << 0 << ovl.Expression->getSourceRange(); + + // TODO: I believe we only end up here if there's a mix of + // static and non-static candidates (otherwise the expression + // would have 'bound member' type, not 'overload' type). + // Ideally we would note which candidate was chosen and why + // the static candidates were rejected. + SrcExpr = ExprError(); + return true; + } + + // Fix the expression to refer to 'fn'. + SingleFunctionExpression = + FixOverloadedFunctionReference(SrcExpr.get(), found, fn); + + // If desired, do function-to-pointer decay. + if (doFunctionPointerConverion) { + SingleFunctionExpression = + DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get()); + if (SingleFunctionExpression.isInvalid()) { + SrcExpr = ExprError(); + return true; + } + } + } + + if (!SingleFunctionExpression.isUsable()) { + if (complain) { + Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining) + << ovl.Expression->getName() + << DestTypeForComplaining + << OpRangeForComplaining + << ovl.Expression->getQualifierLoc().getSourceRange(); + NoteAllOverloadCandidates(SrcExpr.get()); + + SrcExpr = ExprError(); + return true; + } + + return false; + } + + SrcExpr = SingleFunctionExpression; + return true; +} + +/// Add a single candidate to the overload set. +static void AddOverloadedCallCandidate(Sema &S, + DeclAccessPair FoundDecl, + TemplateArgumentListInfo *ExplicitTemplateArgs, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, + bool PartialOverloading, + bool KnownValid) { + NamedDecl *Callee = FoundDecl.getDecl(); + if (isa<UsingShadowDecl>(Callee)) + Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); + + if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { + if (ExplicitTemplateArgs) { + assert(!KnownValid && "Explicit template arguments?"); + return; + } + // Prevent ill-formed function decls to be added as overload candidates. + if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>())) + return; + + S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet, + /*SuppressUsedConversions=*/false, + PartialOverloading); + return; + } + + if (FunctionTemplateDecl *FuncTemplate + = dyn_cast<FunctionTemplateDecl>(Callee)) { + S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, + ExplicitTemplateArgs, Args, CandidateSet, + /*SuppressUsedConversions=*/false, + PartialOverloading); + return; + } + + assert(!KnownValid && "unhandled case in overloaded call candidate"); +} + +/// Add the overload candidates named by callee and/or found by argument +/// dependent lookup to the given overload set. +void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, + ArrayRef<Expr *> Args, + OverloadCandidateSet &CandidateSet, + bool PartialOverloading) { + +#ifndef NDEBUG + // Verify that ArgumentDependentLookup is consistent with the rules + // in C++0x [basic.lookup.argdep]p3: + // + // Let X be the lookup set produced by unqualified lookup (3.4.1) + // and let Y be the lookup set produced by argument dependent + // lookup (defined as follows). If X contains + // + // -- a declaration of a class member, or + // + // -- a block-scope function declaration that is not a + // using-declaration, or + // + // -- a declaration that is neither a function or a function + // template + // + // then Y is empty. + + if (ULE->requiresADL()) { + for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), + E = ULE->decls_end(); I != E; ++I) { + assert(!(*I)->getDeclContext()->isRecord()); + assert(isa<UsingShadowDecl>(*I) || + !(*I)->getDeclContext()->isFunctionOrMethod()); + assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); + } + } +#endif + + // It would be nice to avoid this copy. + TemplateArgumentListInfo TABuffer; + TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr; + if (ULE->hasExplicitTemplateArgs()) { + ULE->copyTemplateArgumentsInto(TABuffer); + ExplicitTemplateArgs = &TABuffer; + } + + for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), + E = ULE->decls_end(); I != E; ++I) + AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args, + CandidateSet, PartialOverloading, + /*KnownValid*/ true); + + if (ULE->requiresADL()) + AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(), + Args, ExplicitTemplateArgs, + CandidateSet, PartialOverloading); +} + +/// Determine whether a declaration with the specified name could be moved into +/// a different namespace. +static bool canBeDeclaredInNamespace(const DeclarationName &Name) { + switch (Name.getCXXOverloadedOperator()) { + case OO_New: case OO_Array_New: + case OO_Delete: case OO_Array_Delete: + return false; + + default: + return true; + } +} + +/// Attempt to recover from an ill-formed use of a non-dependent name in a +/// template, where the non-dependent name was declared after the template +/// was defined. This is common in code written for a compilers which do not +/// correctly implement two-stage name lookup. +/// +/// Returns true if a viable candidate was found and a diagnostic was issued. +static bool +DiagnoseTwoPhaseLookup(Sema &SemaRef, SourceLocation FnLoc, + const CXXScopeSpec &SS, LookupResult &R, + OverloadCandidateSet::CandidateSetKind CSK, + TemplateArgumentListInfo *ExplicitTemplateArgs, + ArrayRef<Expr *> Args, + bool *DoDiagnoseEmptyLookup = nullptr) { + if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty()) + return false; + + for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) { + if (DC->isTransparentContext()) + continue; + + SemaRef.LookupQualifiedName(R, DC); + + if (!R.empty()) { + R.suppressDiagnostics(); + + if (isa<CXXRecordDecl>(DC)) { + // Don't diagnose names we find in classes; we get much better + // diagnostics for these from DiagnoseEmptyLookup. + R.clear(); + if (DoDiagnoseEmptyLookup) + *DoDiagnoseEmptyLookup = true; + return false; + } + + OverloadCandidateSet Candidates(FnLoc, CSK); + for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) + AddOverloadedCallCandidate(SemaRef, I.getPair(), + ExplicitTemplateArgs, Args, + Candidates, false, /*KnownValid*/ false); + + OverloadCandidateSet::iterator Best; + if (Candidates.BestViableFunction(SemaRef, FnLoc, Best) != OR_Success) { + // No viable functions. Don't bother the user with notes for functions + // which don't work and shouldn't be found anyway. + R.clear(); + return false; + } + + // Find the namespaces where ADL would have looked, and suggest + // declaring the function there instead. + Sema::AssociatedNamespaceSet AssociatedNamespaces; + Sema::AssociatedClassSet AssociatedClasses; + SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args, + AssociatedNamespaces, + AssociatedClasses); + Sema::AssociatedNamespaceSet SuggestedNamespaces; + if (canBeDeclaredInNamespace(R.getLookupName())) { + DeclContext *Std = SemaRef.getStdNamespace(); + for (Sema::AssociatedNamespaceSet::iterator + it = AssociatedNamespaces.begin(), + end = AssociatedNamespaces.end(); it != end; ++it) { + // Never suggest declaring a function within namespace 'std'. + if (Std && Std->Encloses(*it)) + continue; + + // Never suggest declaring a function within a namespace with a + // reserved name, like __gnu_cxx. + NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it); + if (NS && + NS->getQualifiedNameAsString().find("__") != std::string::npos) + continue; + + SuggestedNamespaces.insert(*it); + } + } + + SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup) + << R.getLookupName(); + if (SuggestedNamespaces.empty()) { + SemaRef.Diag(Best->Function->getLocation(), + diag::note_not_found_by_two_phase_lookup) + << R.getLookupName() << 0; + } else if (SuggestedNamespaces.size() == 1) { + SemaRef.Diag(Best->Function->getLocation(), + diag::note_not_found_by_two_phase_lookup) + << R.getLookupName() << 1 << *SuggestedNamespaces.begin(); + } else { + // FIXME: It would be useful to list the associated namespaces here, + // but the diagnostics infrastructure doesn't provide a way to produce + // a localized representation of a list of items. + SemaRef.Diag(Best->Function->getLocation(), + diag::note_not_found_by_two_phase_lookup) + << R.getLookupName() << 2; + } + + // Try to recover by calling this function. + return true; + } + + R.clear(); + } + + return false; +} + +/// Attempt to recover from ill-formed use of a non-dependent operator in a +/// template, where the non-dependent operator was declared after the template +/// was defined. +/// +/// Returns true if a viable candidate was found and a diagnostic was issued. +static bool +DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op, + SourceLocation OpLoc, + ArrayRef<Expr *> Args) { + DeclarationName OpName = + SemaRef.Context.DeclarationNames.getCXXOperatorName(Op); + LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName); + return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R, + OverloadCandidateSet::CSK_Operator, + /*ExplicitTemplateArgs=*/nullptr, Args); +} + +namespace { +class BuildRecoveryCallExprRAII { + Sema &SemaRef; +public: + BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) { + assert(SemaRef.IsBuildingRecoveryCallExpr == false); + SemaRef.IsBuildingRecoveryCallExpr = true; + } + + ~BuildRecoveryCallExprRAII() { + SemaRef.IsBuildingRecoveryCallExpr = false; + } +}; + +} + +static std::unique_ptr<CorrectionCandidateCallback> +MakeValidator(Sema &SemaRef, MemberExpr *ME, size_t NumArgs, + bool HasTemplateArgs, bool AllowTypoCorrection) { + if (!AllowTypoCorrection) + return llvm::make_unique<NoTypoCorrectionCCC>(); + return llvm::make_unique<FunctionCallFilterCCC>(SemaRef, NumArgs, + HasTemplateArgs, ME); +} + +/// Attempts to recover from a call where no functions were found. +/// +/// Returns true if new candidates were found. +static ExprResult +BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, + UnresolvedLookupExpr *ULE, + SourceLocation LParenLoc, + MutableArrayRef<Expr *> Args, + SourceLocation RParenLoc, + bool EmptyLookup, bool AllowTypoCorrection) { + // Do not try to recover if it is already building a recovery call. + // This stops infinite loops for template instantiations like + // + // template <typename T> auto foo(T t) -> decltype(foo(t)) {} + // template <typename T> auto foo(T t) -> decltype(foo(&t)) {} + // + if (SemaRef.IsBuildingRecoveryCallExpr) + return ExprError(); + BuildRecoveryCallExprRAII RCE(SemaRef); + + CXXScopeSpec SS; + SS.Adopt(ULE->getQualifierLoc()); + SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc(); + + TemplateArgumentListInfo TABuffer; + TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr; + if (ULE->hasExplicitTemplateArgs()) { + ULE->copyTemplateArgumentsInto(TABuffer); + ExplicitTemplateArgs = &TABuffer; + } + + LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), + Sema::LookupOrdinaryName); + bool DoDiagnoseEmptyLookup = EmptyLookup; + if (!DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R, + OverloadCandidateSet::CSK_Normal, + ExplicitTemplateArgs, Args, + &DoDiagnoseEmptyLookup) && + (!DoDiagnoseEmptyLookup || SemaRef.DiagnoseEmptyLookup( + S, SS, R, + MakeValidator(SemaRef, dyn_cast<MemberExpr>(Fn), Args.size(), + ExplicitTemplateArgs != nullptr, AllowTypoCorrection), + ExplicitTemplateArgs, Args))) + return ExprError(); + + assert(!R.empty() && "lookup results empty despite recovery"); + + // If recovery created an ambiguity, just bail out. + if (R.isAmbiguous()) { + R.suppressDiagnostics(); + return ExprError(); + } + + // Build an implicit member call if appropriate. Just drop the + // casts and such from the call, we don't really care. + ExprResult NewFn = ExprError(); + if ((*R.begin())->isCXXClassMember()) + NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R, + ExplicitTemplateArgs, S); + else if (ExplicitTemplateArgs || TemplateKWLoc.isValid()) + NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false, + ExplicitTemplateArgs); + else + NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); + + if (NewFn.isInvalid()) + return ExprError(); + + // This shouldn't cause an infinite loop because we're giving it + // an expression with viable lookup results, which should never + // end up here. + return SemaRef.ActOnCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc, + MultiExprArg(Args.data(), Args.size()), + RParenLoc); +} + +/// Constructs and populates an OverloadedCandidateSet from +/// the given function. +/// \returns true when an the ExprResult output parameter has been set. +bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn, + UnresolvedLookupExpr *ULE, + MultiExprArg Args, + SourceLocation RParenLoc, + OverloadCandidateSet *CandidateSet, + ExprResult *Result) { +#ifndef NDEBUG + if (ULE->requiresADL()) { + // To do ADL, we must have found an unqualified name. + assert(!ULE->getQualifier() && "qualified name with ADL"); + + // We don't perform ADL for implicit declarations of builtins. + // Verify that this was correctly set up. + FunctionDecl *F; + if (ULE->decls_begin() + 1 == ULE->decls_end() && + (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && + F->getBuiltinID() && F->isImplicit()) + llvm_unreachable("performing ADL for builtin"); + + // We don't perform ADL in C. + assert(getLangOpts().CPlusPlus && "ADL enabled in C"); + } +#endif + + UnbridgedCastsSet UnbridgedCasts; + if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) { + *Result = ExprError(); + return true; + } + + // Add the functions denoted by the callee to the set of candidate + // functions, including those from argument-dependent lookup. + AddOverloadedCallCandidates(ULE, Args, *CandidateSet); + + if (getLangOpts().MSVCCompat && + CurContext->isDependentContext() && !isSFINAEContext() && + (isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) { + + OverloadCandidateSet::iterator Best; + if (CandidateSet->empty() || + CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) == + OR_No_Viable_Function) { + // In Microsoft mode, if we are inside a template class member function + // then create a type dependent CallExpr. The goal is to postpone name + // lookup to instantiation time to be able to search into type dependent + // base classes. + CallExpr *CE = CallExpr::Create(Context, Fn, Args, Context.DependentTy, + VK_RValue, RParenLoc); + CE->setTypeDependent(true); + CE->setValueDependent(true); + CE->setInstantiationDependent(true); + *Result = CE; + return true; + } + } + + if (CandidateSet->empty()) + return false; + + UnbridgedCasts.restore(); + return false; +} + +/// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns +/// the completed call expression. If overload resolution fails, emits +/// diagnostics and returns ExprError() +static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, + UnresolvedLookupExpr *ULE, + SourceLocation LParenLoc, + MultiExprArg Args, + SourceLocation RParenLoc, + Expr *ExecConfig, + OverloadCandidateSet *CandidateSet, + OverloadCandidateSet::iterator *Best, + OverloadingResult OverloadResult, + bool AllowTypoCorrection) { + if (CandidateSet->empty()) + return BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc, Args, + RParenLoc, /*EmptyLookup=*/true, + AllowTypoCorrection); + + switch (OverloadResult) { + case OR_Success: { + FunctionDecl *FDecl = (*Best)->Function; + SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl); + if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc())) + return ExprError(); + Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl); + return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc, + ExecConfig, /*IsExecConfig=*/false, + (*Best)->IsADLCandidate); + } + + case OR_No_Viable_Function: { + // Try to recover by looking for viable functions which the user might + // have meant to call. + ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc, + Args, RParenLoc, + /*EmptyLookup=*/false, + AllowTypoCorrection); + if (!Recovery.isInvalid()) + return Recovery; + + // If the user passes in a function that we can't take the address of, we + // generally end up emitting really bad error messages. Here, we attempt to + // emit better ones. + for (const Expr *Arg : Args) { + if (!Arg->getType()->isFunctionType()) + continue; + if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) { + auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()); + if (FD && + !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true, + Arg->getExprLoc())) + return ExprError(); + } + } + + SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_no_viable_function_in_call) + << ULE->getName() << Fn->getSourceRange(); + CandidateSet->NoteCandidates(SemaRef, OCD_AllCandidates, Args); + break; + } + + case OR_Ambiguous: + SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_ambiguous_call) + << ULE->getName() << Fn->getSourceRange(); + CandidateSet->NoteCandidates(SemaRef, OCD_ViableCandidates, Args); + break; + + case OR_Deleted: { + SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_deleted_call) + << (*Best)->Function->isDeleted() << ULE->getName() + << SemaRef.getDeletedOrUnavailableSuffix((*Best)->Function) + << Fn->getSourceRange(); + CandidateSet->NoteCandidates(SemaRef, OCD_AllCandidates, Args); + + // We emitted an error for the unavailable/deleted function call but keep + // the call in the AST. + FunctionDecl *FDecl = (*Best)->Function; + Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl); + return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc, + ExecConfig, /*IsExecConfig=*/false, + (*Best)->IsADLCandidate); + } + } + + // Overload resolution failed. + return ExprError(); +} + +static void markUnaddressableCandidatesUnviable(Sema &S, + OverloadCandidateSet &CS) { + for (auto I = CS.begin(), E = CS.end(); I != E; ++I) { + if (I->Viable && + !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) { + I->Viable = false; + I->FailureKind = ovl_fail_addr_not_available; + } + } +} + +/// BuildOverloadedCallExpr - Given the call expression that calls Fn +/// (which eventually refers to the declaration Func) and the call +/// arguments Args/NumArgs, attempt to resolve the function call down +/// to a specific function. If overload resolution succeeds, returns +/// the call expression produced by overload resolution. +/// Otherwise, emits diagnostics and returns ExprError. +ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, + UnresolvedLookupExpr *ULE, + SourceLocation LParenLoc, + MultiExprArg Args, + SourceLocation RParenLoc, + Expr *ExecConfig, + bool AllowTypoCorrection, + bool CalleesAddressIsTaken) { + OverloadCandidateSet CandidateSet(Fn->getExprLoc(), + OverloadCandidateSet::CSK_Normal); + ExprResult result; + + if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet, + &result)) + return result; + + // If the user handed us something like `(&Foo)(Bar)`, we need to ensure that + // functions that aren't addressible are considered unviable. + if (CalleesAddressIsTaken) + markUnaddressableCandidatesUnviable(*this, CandidateSet); + + OverloadCandidateSet::iterator Best; + OverloadingResult OverloadResult = + CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best); + + return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, + RParenLoc, ExecConfig, &CandidateSet, + &Best, OverloadResult, + AllowTypoCorrection); +} + +static bool IsOverloaded(const UnresolvedSetImpl &Functions) { + return Functions.size() > 1 || + (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); +} + +/// Create a unary operation that may resolve to an overloaded +/// operator. +/// +/// \param OpLoc The location of the operator itself (e.g., '*'). +/// +/// \param Opc The UnaryOperatorKind that describes this operator. +/// +/// \param Fns The set of non-member functions that will be +/// considered by overload resolution. The caller needs to build this +/// set based on the context using, e.g., +/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This +/// set should not contain any member functions; those will be added +/// by CreateOverloadedUnaryOp(). +/// +/// \param Input The input argument. +ExprResult +Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc, + const UnresolvedSetImpl &Fns, + Expr *Input, bool PerformADL) { + OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); + assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); + DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); + // TODO: provide better source location info. + DeclarationNameInfo OpNameInfo(OpName, OpLoc); + + if (checkPlaceholderForOverload(*this, Input)) + return ExprError(); + + Expr *Args[2] = { Input, nullptr }; + unsigned NumArgs = 1; + + // For post-increment and post-decrement, add the implicit '0' as + // the second argument, so that we know this is a post-increment or + // post-decrement. + if (Opc == UO_PostInc || Opc == UO_PostDec) { + llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); + Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy, + SourceLocation()); + NumArgs = 2; + } + + ArrayRef<Expr *> ArgsArray(Args, NumArgs); + + if (Input->isTypeDependent()) { + if (Fns.empty()) + return new (Context) UnaryOperator(Input, Opc, Context.DependentTy, + VK_RValue, OK_Ordinary, OpLoc, false); + + CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators + UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create( + Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo, + /*ADL*/ true, IsOverloaded(Fns), Fns.begin(), Fns.end()); + return CXXOperatorCallExpr::Create(Context, Op, Fn, ArgsArray, + Context.DependentTy, VK_RValue, OpLoc, + FPOptions()); + } + + // Build an empty overload set. + OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator); + + // Add the candidates from the given function set. + AddFunctionCandidates(Fns, ArgsArray, CandidateSet); + + // Add operator candidates that are member functions. + AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet); + + // Add candidates from ADL. + if (PerformADL) { + AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray, + /*ExplicitTemplateArgs*/nullptr, + CandidateSet); + } + + // Add builtin operator candidates. + AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet); + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { + case OR_Success: { + // We found a built-in operator or an overloaded operator. + FunctionDecl *FnDecl = Best->Function; + + if (FnDecl) { + Expr *Base = nullptr; + // We matched an overloaded operator. Build a call to that + // operator. + + // Convert the arguments. + if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { + CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl); + + ExprResult InputRes = + PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr, + Best->FoundDecl, Method); + if (InputRes.isInvalid()) + return ExprError(); + Base = Input = InputRes.get(); + } else { + // Convert the arguments. + ExprResult InputInit + = PerformCopyInitialization(InitializedEntity::InitializeParameter( + Context, + FnDecl->getParamDecl(0)), + SourceLocation(), + Input); + if (InputInit.isInvalid()) + return ExprError(); + Input = InputInit.get(); + } + + // Build the actual expression node. + ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl, + Base, HadMultipleCandidates, + OpLoc); + if (FnExpr.isInvalid()) + return ExprError(); + + // Determine the result type. + QualType ResultTy = FnDecl->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + + Args[0] = Input; + CallExpr *TheCall = CXXOperatorCallExpr::Create( + Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc, + FPOptions(), Best->IsADLCandidate); + + if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl)) + return ExprError(); + + if (CheckFunctionCall(FnDecl, TheCall, + FnDecl->getType()->castAs<FunctionProtoType>())) + return ExprError(); + + return MaybeBindToTemporary(TheCall); + } else { + // We matched a built-in operator. Convert the arguments, then + // break out so that we will build the appropriate built-in + // operator node. + ExprResult InputRes = PerformImplicitConversion( + Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing, + CCK_ForBuiltinOverloadedOp); + if (InputRes.isInvalid()) + return ExprError(); + Input = InputRes.get(); + break; + } + } + + case OR_No_Viable_Function: + // This is an erroneous use of an operator which can be overloaded by + // a non-member function. Check for non-member operators which were + // defined too late to be candidates. + if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray)) + // FIXME: Recover by calling the found function. + return ExprError(); + + // No viable function; fall through to handling this as a + // built-in operator, which will produce an error message for us. + break; + + case OR_Ambiguous: + Diag(OpLoc, diag::err_ovl_ambiguous_oper_unary) + << UnaryOperator::getOpcodeStr(Opc) + << Input->getType() + << Input->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, ArgsArray, + UnaryOperator::getOpcodeStr(Opc), OpLoc); + return ExprError(); + + case OR_Deleted: + Diag(OpLoc, diag::err_ovl_deleted_oper) + << Best->Function->isDeleted() + << UnaryOperator::getOpcodeStr(Opc) + << getDeletedOrUnavailableSuffix(Best->Function) + << Input->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, ArgsArray, + UnaryOperator::getOpcodeStr(Opc), OpLoc); + return ExprError(); + } + + // Either we found no viable overloaded operator or we matched a + // built-in operator. In either case, fall through to trying to + // build a built-in operation. + return CreateBuiltinUnaryOp(OpLoc, Opc, Input); +} + +/// Create a binary operation that may resolve to an overloaded +/// operator. +/// +/// \param OpLoc The location of the operator itself (e.g., '+'). +/// +/// \param Opc The BinaryOperatorKind that describes this operator. +/// +/// \param Fns The set of non-member functions that will be +/// considered by overload resolution. The caller needs to build this +/// set based on the context using, e.g., +/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This +/// set should not contain any member functions; those will be added +/// by CreateOverloadedBinOp(). +/// +/// \param LHS Left-hand argument. +/// \param RHS Right-hand argument. +ExprResult +Sema::CreateOverloadedBinOp(SourceLocation OpLoc, + BinaryOperatorKind Opc, + const UnresolvedSetImpl &Fns, + Expr *LHS, Expr *RHS, bool PerformADL) { + Expr *Args[2] = { LHS, RHS }; + LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple + + OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); + DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); + + // If either side is type-dependent, create an appropriate dependent + // expression. + if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { + if (Fns.empty()) { + // If there are no functions to store, just build a dependent + // BinaryOperator or CompoundAssignment. + if (Opc <= BO_Assign || Opc > BO_OrAssign) + return new (Context) BinaryOperator( + Args[0], Args[1], Opc, Context.DependentTy, VK_RValue, OK_Ordinary, + OpLoc, FPFeatures); + + return new (Context) CompoundAssignOperator( + Args[0], Args[1], Opc, Context.DependentTy, VK_LValue, OK_Ordinary, + Context.DependentTy, Context.DependentTy, OpLoc, + FPFeatures); + } + + // FIXME: save results of ADL from here? + CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators + // TODO: provide better source location info in DNLoc component. + DeclarationNameInfo OpNameInfo(OpName, OpLoc); + UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create( + Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo, + /*ADL*/ PerformADL, IsOverloaded(Fns), Fns.begin(), Fns.end()); + return CXXOperatorCallExpr::Create(Context, Op, Fn, Args, + Context.DependentTy, VK_RValue, OpLoc, + FPFeatures); + } + + // Always do placeholder-like conversions on the RHS. + if (checkPlaceholderForOverload(*this, Args[1])) + return ExprError(); + + // Do placeholder-like conversion on the LHS; note that we should + // not get here with a PseudoObject LHS. + assert(Args[0]->getObjectKind() != OK_ObjCProperty); + if (checkPlaceholderForOverload(*this, Args[0])) + return ExprError(); + + // If this is the assignment operator, we only perform overload resolution + // if the left-hand side is a class or enumeration type. This is actually + // a hack. The standard requires that we do overload resolution between the + // various built-in candidates, but as DR507 points out, this can lead to + // problems. So we do it this way, which pretty much follows what GCC does. + // Note that we go the traditional code path for compound assignment forms. + if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType()) + return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); + + // If this is the .* operator, which is not overloadable, just + // create a built-in binary operator. + if (Opc == BO_PtrMemD) + return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); + + // Build an empty overload set. + OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator); + + // Add the candidates from the given function set. + AddFunctionCandidates(Fns, Args, CandidateSet); + + // Add operator candidates that are member functions. + AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet); + + // Add candidates from ADL. Per [over.match.oper]p2, this lookup is not + // performed for an assignment operator (nor for operator[] nor operator->, + // which don't get here). + if (Opc != BO_Assign && PerformADL) + AddArgumentDependentLookupCandidates(OpName, OpLoc, Args, + /*ExplicitTemplateArgs*/ nullptr, + CandidateSet); + + // Add builtin operator candidates. + AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet); + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { + case OR_Success: { + // We found a built-in operator or an overloaded operator. + FunctionDecl *FnDecl = Best->Function; + + if (FnDecl) { + Expr *Base = nullptr; + // We matched an overloaded operator. Build a call to that + // operator. + + // Convert the arguments. + if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { + // Best->Access is only meaningful for class members. + CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); + + ExprResult Arg1 = + PerformCopyInitialization( + InitializedEntity::InitializeParameter(Context, + FnDecl->getParamDecl(0)), + SourceLocation(), Args[1]); + if (Arg1.isInvalid()) + return ExprError(); + + ExprResult Arg0 = + PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr, + Best->FoundDecl, Method); + if (Arg0.isInvalid()) + return ExprError(); + Base = Args[0] = Arg0.getAs<Expr>(); + Args[1] = RHS = Arg1.getAs<Expr>(); + } else { + // Convert the arguments. + ExprResult Arg0 = PerformCopyInitialization( + InitializedEntity::InitializeParameter(Context, + FnDecl->getParamDecl(0)), + SourceLocation(), Args[0]); + if (Arg0.isInvalid()) + return ExprError(); + + ExprResult Arg1 = + PerformCopyInitialization( + InitializedEntity::InitializeParameter(Context, + FnDecl->getParamDecl(1)), + SourceLocation(), Args[1]); + if (Arg1.isInvalid()) + return ExprError(); + Args[0] = LHS = Arg0.getAs<Expr>(); + Args[1] = RHS = Arg1.getAs<Expr>(); + } + + // Build the actual expression node. + ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, + Best->FoundDecl, Base, + HadMultipleCandidates, OpLoc); + if (FnExpr.isInvalid()) + return ExprError(); + + // Determine the result type. + QualType ResultTy = FnDecl->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + + CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create( + Context, Op, FnExpr.get(), Args, ResultTy, VK, OpLoc, FPFeatures, + Best->IsADLCandidate); + + if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, + FnDecl)) + return ExprError(); + + ArrayRef<const Expr *> ArgsArray(Args, 2); + const Expr *ImplicitThis = nullptr; + // Cut off the implicit 'this'. + if (isa<CXXMethodDecl>(FnDecl)) { + ImplicitThis = ArgsArray[0]; + ArgsArray = ArgsArray.slice(1); + } + + // Check for a self move. + if (Op == OO_Equal) + DiagnoseSelfMove(Args[0], Args[1], OpLoc); + + checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray, + isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(), + VariadicDoesNotApply); + + return MaybeBindToTemporary(TheCall); + } else { + // We matched a built-in operator. Convert the arguments, then + // break out so that we will build the appropriate built-in + // operator node. + ExprResult ArgsRes0 = PerformImplicitConversion( + Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0], + AA_Passing, CCK_ForBuiltinOverloadedOp); + if (ArgsRes0.isInvalid()) + return ExprError(); + Args[0] = ArgsRes0.get(); + + ExprResult ArgsRes1 = PerformImplicitConversion( + Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1], + AA_Passing, CCK_ForBuiltinOverloadedOp); + if (ArgsRes1.isInvalid()) + return ExprError(); + Args[1] = ArgsRes1.get(); + break; + } + } + + case OR_No_Viable_Function: { + // C++ [over.match.oper]p9: + // If the operator is the operator , [...] and there are no + // viable functions, then the operator is assumed to be the + // built-in operator and interpreted according to clause 5. + if (Opc == BO_Comma) + break; + + // For class as left operand for assignment or compound assignment + // operator do not fall through to handling in built-in, but report that + // no overloaded assignment operator found + ExprResult Result = ExprError(); + if (Args[0]->getType()->isRecordType() && + Opc >= BO_Assign && Opc <= BO_OrAssign) { + Diag(OpLoc, diag::err_ovl_no_viable_oper) + << BinaryOperator::getOpcodeStr(Opc) + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + if (Args[0]->getType()->isIncompleteType()) { + Diag(OpLoc, diag::note_assign_lhs_incomplete) + << Args[0]->getType() + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + } + } else { + // This is an erroneous use of an operator which can be overloaded by + // a non-member function. Check for non-member operators which were + // defined too late to be candidates. + if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args)) + // FIXME: Recover by calling the found function. + return ExprError(); + + // No viable function; try to create a built-in operation, which will + // produce an error. Then, show the non-viable candidates. + Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); + } + assert(Result.isInvalid() && + "C++ binary operator overloading is missing candidates!"); + if (Result.isInvalid()) + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, + BinaryOperator::getOpcodeStr(Opc), OpLoc); + return Result; + } + + case OR_Ambiguous: + Diag(OpLoc, diag::err_ovl_ambiguous_oper_binary) + << BinaryOperator::getOpcodeStr(Opc) + << Args[0]->getType() << Args[1]->getType() + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args, + BinaryOperator::getOpcodeStr(Opc), OpLoc); + return ExprError(); + + case OR_Deleted: + if (isImplicitlyDeleted(Best->Function)) { + CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); + Diag(OpLoc, diag::err_ovl_deleted_special_oper) + << Context.getRecordType(Method->getParent()) + << getSpecialMember(Method); + + // The user probably meant to call this special member. Just + // explain why it's deleted. + NoteDeletedFunction(Method); + return ExprError(); + } else { + Diag(OpLoc, diag::err_ovl_deleted_oper) + << Best->Function->isDeleted() + << BinaryOperator::getOpcodeStr(Opc) + << getDeletedOrUnavailableSuffix(Best->Function) + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + } + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, + BinaryOperator::getOpcodeStr(Opc), OpLoc); + return ExprError(); + } + + // We matched a built-in operator; build it. + return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); +} + +ExprResult +Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, + SourceLocation RLoc, + Expr *Base, Expr *Idx) { + Expr *Args[2] = { Base, Idx }; + DeclarationName OpName = + Context.DeclarationNames.getCXXOperatorName(OO_Subscript); + + // If either side is type-dependent, create an appropriate dependent + // expression. + if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { + + CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators + // CHECKME: no 'operator' keyword? + DeclarationNameInfo OpNameInfo(OpName, LLoc); + OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc)); + UnresolvedLookupExpr *Fn + = UnresolvedLookupExpr::Create(Context, NamingClass, + NestedNameSpecifierLoc(), OpNameInfo, + /*ADL*/ true, /*Overloaded*/ false, + UnresolvedSetIterator(), + UnresolvedSetIterator()); + // Can't add any actual overloads yet + + return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn, Args, + Context.DependentTy, VK_RValue, RLoc, + FPOptions()); + } + + // Handle placeholders on both operands. + if (checkPlaceholderForOverload(*this, Args[0])) + return ExprError(); + if (checkPlaceholderForOverload(*this, Args[1])) + return ExprError(); + + // Build an empty overload set. + OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator); + + // Subscript can only be overloaded as a member function. + + // Add operator candidates that are member functions. + AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet); + + // Add builtin operator candidates. + AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet); + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) { + case OR_Success: { + // We found a built-in operator or an overloaded operator. + FunctionDecl *FnDecl = Best->Function; + + if (FnDecl) { + // We matched an overloaded operator. Build a call to that + // operator. + + CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); + + // Convert the arguments. + CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); + ExprResult Arg0 = + PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr, + Best->FoundDecl, Method); + if (Arg0.isInvalid()) + return ExprError(); + Args[0] = Arg0.get(); + + // Convert the arguments. + ExprResult InputInit + = PerformCopyInitialization(InitializedEntity::InitializeParameter( + Context, + FnDecl->getParamDecl(0)), + SourceLocation(), + Args[1]); + if (InputInit.isInvalid()) + return ExprError(); + + Args[1] = InputInit.getAs<Expr>(); + + // Build the actual expression node. + DeclarationNameInfo OpLocInfo(OpName, LLoc); + OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc)); + ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, + Best->FoundDecl, + Base, + HadMultipleCandidates, + OpLocInfo.getLoc(), + OpLocInfo.getInfo()); + if (FnExpr.isInvalid()) + return ExprError(); + + // Determine the result type + QualType ResultTy = FnDecl->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + + CXXOperatorCallExpr *TheCall = + CXXOperatorCallExpr::Create(Context, OO_Subscript, FnExpr.get(), + Args, ResultTy, VK, RLoc, FPOptions()); + + if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl)) + return ExprError(); + + if (CheckFunctionCall(Method, TheCall, + Method->getType()->castAs<FunctionProtoType>())) + return ExprError(); + + return MaybeBindToTemporary(TheCall); + } else { + // We matched a built-in operator. Convert the arguments, then + // break out so that we will build the appropriate built-in + // operator node. + ExprResult ArgsRes0 = PerformImplicitConversion( + Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0], + AA_Passing, CCK_ForBuiltinOverloadedOp); + if (ArgsRes0.isInvalid()) + return ExprError(); + Args[0] = ArgsRes0.get(); + + ExprResult ArgsRes1 = PerformImplicitConversion( + Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1], + AA_Passing, CCK_ForBuiltinOverloadedOp); + if (ArgsRes1.isInvalid()) + return ExprError(); + Args[1] = ArgsRes1.get(); + + break; + } + } + + case OR_No_Viable_Function: { + if (CandidateSet.empty()) + Diag(LLoc, diag::err_ovl_no_oper) + << Args[0]->getType() << /*subscript*/ 0 + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + else + Diag(LLoc, diag::err_ovl_no_viable_subscript) + << Args[0]->getType() + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, + "[]", LLoc); + return ExprError(); + } + + case OR_Ambiguous: + Diag(LLoc, diag::err_ovl_ambiguous_oper_binary) + << "[]" + << Args[0]->getType() << Args[1]->getType() + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args, + "[]", LLoc); + return ExprError(); + + case OR_Deleted: + Diag(LLoc, diag::err_ovl_deleted_oper) + << Best->Function->isDeleted() << "[]" + << getDeletedOrUnavailableSuffix(Best->Function) + << Args[0]->getSourceRange() << Args[1]->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args, + "[]", LLoc); + return ExprError(); + } + + // We matched a built-in operator; build it. + return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc); +} + +/// BuildCallToMemberFunction - Build a call to a member +/// function. MemExpr is the expression that refers to the member +/// function (and includes the object parameter), Args/NumArgs are the +/// arguments to the function call (not including the object +/// parameter). The caller needs to validate that the member +/// expression refers to a non-static member function or an overloaded +/// member function. +ExprResult +Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, + SourceLocation LParenLoc, + MultiExprArg Args, + SourceLocation RParenLoc) { + assert(MemExprE->getType() == Context.BoundMemberTy || + MemExprE->getType() == Context.OverloadTy); + + // Dig out the member expression. This holds both the object + // argument and the member function we're referring to. + Expr *NakedMemExpr = MemExprE->IgnoreParens(); + + // Determine whether this is a call to a pointer-to-member function. + if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) { + assert(op->getType() == Context.BoundMemberTy); + assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI); + + QualType fnType = + op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType(); + + const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>(); + QualType resultType = proto->getCallResultType(Context); + ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType()); + + // Check that the object type isn't more qualified than the + // member function we're calling. + Qualifiers funcQuals = proto->getTypeQuals(); + + QualType objectType = op->getLHS()->getType(); + if (op->getOpcode() == BO_PtrMemI) + objectType = objectType->castAs<PointerType>()->getPointeeType(); + Qualifiers objectQuals = objectType.getQualifiers(); + + Qualifiers difference = objectQuals - funcQuals; + difference.removeObjCGCAttr(); + difference.removeAddressSpace(); + if (difference) { + std::string qualsString = difference.getAsString(); + Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals) + << fnType.getUnqualifiedType() + << qualsString + << (qualsString.find(' ') == std::string::npos ? 1 : 2); + } + + CXXMemberCallExpr *call = + CXXMemberCallExpr::Create(Context, MemExprE, Args, resultType, + valueKind, RParenLoc, proto->getNumParams()); + + if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(), + call, nullptr)) + return ExprError(); + + if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc)) + return ExprError(); + + if (CheckOtherCall(call, proto)) + return ExprError(); + + return MaybeBindToTemporary(call); + } + + if (isa<CXXPseudoDestructorExpr>(NakedMemExpr)) + return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_RValue, + RParenLoc); + + UnbridgedCastsSet UnbridgedCasts; + if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) + return ExprError(); + + MemberExpr *MemExpr; + CXXMethodDecl *Method = nullptr; + DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public); + NestedNameSpecifier *Qualifier = nullptr; + if (isa<MemberExpr>(NakedMemExpr)) { + MemExpr = cast<MemberExpr>(NakedMemExpr); + Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); + FoundDecl = MemExpr->getFoundDecl(); + Qualifier = MemExpr->getQualifier(); + UnbridgedCasts.restore(); + } else { + UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); + Qualifier = UnresExpr->getQualifier(); + + QualType ObjectType = UnresExpr->getBaseType(); + Expr::Classification ObjectClassification + = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue() + : UnresExpr->getBase()->Classify(Context); + + // Add overload candidates + OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(), + OverloadCandidateSet::CSK_Normal); + + // FIXME: avoid copy. + TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; + if (UnresExpr->hasExplicitTemplateArgs()) { + UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); + TemplateArgs = &TemplateArgsBuffer; + } + + for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), + E = UnresExpr->decls_end(); I != E; ++I) { + + NamedDecl *Func = *I; + CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); + if (isa<UsingShadowDecl>(Func)) + Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); + + + // Microsoft supports direct constructor calls. + if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) { + AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), + Args, CandidateSet); + } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) { + // If explicit template arguments were provided, we can't call a + // non-template member function. + if (TemplateArgs) + continue; + + AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, + ObjectClassification, Args, CandidateSet, + /*SuppressUserConversions=*/false); + } else { + AddMethodTemplateCandidate( + cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC, + TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet, + /*SuppressUsedConversions=*/false); + } + } + + DeclarationName DeclName = UnresExpr->getMemberName(); + + UnbridgedCasts.restore(); + + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(), + Best)) { + case OR_Success: + Method = cast<CXXMethodDecl>(Best->Function); + FoundDecl = Best->FoundDecl; + CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); + if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc())) + return ExprError(); + // If FoundDecl is different from Method (such as if one is a template + // and the other a specialization), make sure DiagnoseUseOfDecl is + // called on both. + // FIXME: This would be more comprehensively addressed by modifying + // DiagnoseUseOfDecl to accept both the FoundDecl and the decl + // being used. + if (Method != FoundDecl.getDecl() && + DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc())) + return ExprError(); + break; + + case OR_No_Viable_Function: + Diag(UnresExpr->getMemberLoc(), + diag::err_ovl_no_viable_member_function_in_call) + << DeclName << MemExprE->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + // FIXME: Leaking incoming expressions! + return ExprError(); + + case OR_Ambiguous: + Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) + << DeclName << MemExprE->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + // FIXME: Leaking incoming expressions! + return ExprError(); + + case OR_Deleted: + Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) + << Best->Function->isDeleted() + << DeclName + << getDeletedOrUnavailableSuffix(Best->Function) + << MemExprE->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + // FIXME: Leaking incoming expressions! + return ExprError(); + } + + MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); + + // If overload resolution picked a static member, build a + // non-member call based on that function. + if (Method->isStatic()) { + return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args, + RParenLoc); + } + + MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); + } + + QualType ResultType = Method->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultType); + ResultType = ResultType.getNonLValueExprType(Context); + + assert(Method && "Member call to something that isn't a method?"); + const auto *Proto = Method->getType()->getAs<FunctionProtoType>(); + CXXMemberCallExpr *TheCall = + CXXMemberCallExpr::Create(Context, MemExprE, Args, ResultType, VK, + RParenLoc, Proto->getNumParams()); + + // Check for a valid return type. + if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(), + TheCall, Method)) + return ExprError(); + + // Convert the object argument (for a non-static member function call). + // We only need to do this if there was actually an overload; otherwise + // it was done at lookup. + if (!Method->isStatic()) { + ExprResult ObjectArg = + PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier, + FoundDecl, Method); + if (ObjectArg.isInvalid()) + return ExprError(); + MemExpr->setBase(ObjectArg.get()); + } + + // Convert the rest of the arguments + if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args, + RParenLoc)) + return ExprError(); + + DiagnoseSentinelCalls(Method, LParenLoc, Args); + + if (CheckFunctionCall(Method, TheCall, Proto)) + return ExprError(); + + // In the case the method to call was not selected by the overloading + // resolution process, we still need to handle the enable_if attribute. Do + // that here, so it will not hide previous -- and more relevant -- errors. + if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) { + if (const EnableIfAttr *Attr = CheckEnableIf(Method, Args, true)) { + Diag(MemE->getMemberLoc(), + diag::err_ovl_no_viable_member_function_in_call) + << Method << Method->getSourceRange(); + Diag(Method->getLocation(), + diag::note_ovl_candidate_disabled_by_function_cond_attr) + << Attr->getCond()->getSourceRange() << Attr->getMessage(); + return ExprError(); + } + } + + if ((isa<CXXConstructorDecl>(CurContext) || + isa<CXXDestructorDecl>(CurContext)) && + TheCall->getMethodDecl()->isPure()) { + const CXXMethodDecl *MD = TheCall->getMethodDecl(); + + if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) && + MemExpr->performsVirtualDispatch(getLangOpts())) { + Diag(MemExpr->getBeginLoc(), + diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor) + << MD->getDeclName() << isa<CXXDestructorDecl>(CurContext) + << MD->getParent()->getDeclName(); + + Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName(); + if (getLangOpts().AppleKext) + Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext) + << MD->getParent()->getDeclName() << MD->getDeclName(); + } + } + + if (CXXDestructorDecl *DD = + dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) { + // a->A::f() doesn't go through the vtable, except in AppleKext mode. + bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext; + CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false, + CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true, + MemExpr->getMemberLoc()); + } + + return MaybeBindToTemporary(TheCall); +} + +/// BuildCallToObjectOfClassType - Build a call to an object of class +/// type (C++ [over.call.object]), which can end up invoking an +/// overloaded function call operator (@c operator()) or performing a +/// user-defined conversion on the object argument. +ExprResult +Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj, + SourceLocation LParenLoc, + MultiExprArg Args, + SourceLocation RParenLoc) { + if (checkPlaceholderForOverload(*this, Obj)) + return ExprError(); + ExprResult Object = Obj; + + UnbridgedCastsSet UnbridgedCasts; + if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) + return ExprError(); + + assert(Object.get()->getType()->isRecordType() && + "Requires object type argument"); + const RecordType *Record = Object.get()->getType()->getAs<RecordType>(); + + // C++ [over.call.object]p1: + // If the primary-expression E in the function call syntax + // evaluates to a class object of type "cv T", then the set of + // candidate functions includes at least the function call + // operators of T. The function call operators of T are obtained by + // ordinary lookup of the name operator() in the context of + // (E).operator(). + OverloadCandidateSet CandidateSet(LParenLoc, + OverloadCandidateSet::CSK_Operator); + DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); + + if (RequireCompleteType(LParenLoc, Object.get()->getType(), + diag::err_incomplete_object_call, Object.get())) + return true; + + LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); + LookupQualifiedName(R, Record->getDecl()); + R.suppressDiagnostics(); + + for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); + Oper != OperEnd; ++Oper) { + AddMethodCandidate(Oper.getPair(), Object.get()->getType(), + Object.get()->Classify(Context), Args, CandidateSet, + /*SuppressUserConversions=*/false); + } + + // C++ [over.call.object]p2: + // In addition, for each (non-explicit in C++0x) conversion function + // declared in T of the form + // + // operator conversion-type-id () cv-qualifier; + // + // where cv-qualifier is the same cv-qualification as, or a + // greater cv-qualification than, cv, and where conversion-type-id + // denotes the type "pointer to function of (P1,...,Pn) returning + // R", or the type "reference to pointer to function of + // (P1,...,Pn) returning R", or the type "reference to function + // of (P1,...,Pn) returning R", a surrogate call function [...] + // is also considered as a candidate function. Similarly, + // surrogate call functions are added to the set of candidate + // functions for each conversion function declared in an + // accessible base class provided the function is not hidden + // within T by another intervening declaration. + const auto &Conversions = + cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); + for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) { + NamedDecl *D = *I; + CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); + if (isa<UsingShadowDecl>(D)) + D = cast<UsingShadowDecl>(D)->getTargetDecl(); + + // Skip over templated conversion functions; they aren't + // surrogates. + if (isa<FunctionTemplateDecl>(D)) + continue; + + CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); + if (!Conv->isExplicit()) { + // Strip the reference type (if any) and then the pointer type (if + // any) to get down to what might be a function type. + QualType ConvType = Conv->getConversionType().getNonReferenceType(); + if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) + ConvType = ConvPtrType->getPointeeType(); + + if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) + { + AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, + Object.get(), Args, CandidateSet); + } + } + } + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(), + Best)) { + case OR_Success: + // Overload resolution succeeded; we'll build the appropriate call + // below. + break; + + case OR_No_Viable_Function: + if (CandidateSet.empty()) + Diag(Object.get()->getBeginLoc(), diag::err_ovl_no_oper) + << Object.get()->getType() << /*call*/ 1 + << Object.get()->getSourceRange(); + else + Diag(Object.get()->getBeginLoc(), diag::err_ovl_no_viable_object_call) + << Object.get()->getType() << Object.get()->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + break; + + case OR_Ambiguous: + Diag(Object.get()->getBeginLoc(), diag::err_ovl_ambiguous_object_call) + << Object.get()->getType() << Object.get()->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args); + break; + + case OR_Deleted: + Diag(Object.get()->getBeginLoc(), diag::err_ovl_deleted_object_call) + << Best->Function->isDeleted() << Object.get()->getType() + << getDeletedOrUnavailableSuffix(Best->Function) + << Object.get()->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + break; + } + + if (Best == CandidateSet.end()) + return true; + + UnbridgedCasts.restore(); + + if (Best->Function == nullptr) { + // Since there is no function declaration, this is one of the + // surrogate candidates. Dig out the conversion function. + CXXConversionDecl *Conv + = cast<CXXConversionDecl>( + Best->Conversions[0].UserDefined.ConversionFunction); + + CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, + Best->FoundDecl); + if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc)) + return ExprError(); + assert(Conv == Best->FoundDecl.getDecl() && + "Found Decl & conversion-to-functionptr should be same, right?!"); + // We selected one of the surrogate functions that converts the + // object parameter to a function pointer. Perform the conversion + // on the object argument, then let ActOnCallExpr finish the job. + + // Create an implicit member expr to refer to the conversion operator. + // and then call it. + ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl, + Conv, HadMultipleCandidates); + if (Call.isInvalid()) + return ExprError(); + // Record usage of conversion in an implicit cast. + Call = ImplicitCastExpr::Create(Context, Call.get()->getType(), + CK_UserDefinedConversion, Call.get(), + nullptr, VK_RValue); + + return ActOnCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc); + } + + CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl); + + // We found an overloaded operator(). Build a CXXOperatorCallExpr + // that calls this method, using Object for the implicit object + // parameter and passing along the remaining arguments. + CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); + + // An error diagnostic has already been printed when parsing the declaration. + if (Method->isInvalidDecl()) + return ExprError(); + + const FunctionProtoType *Proto = + Method->getType()->getAs<FunctionProtoType>(); + + unsigned NumParams = Proto->getNumParams(); + + DeclarationNameInfo OpLocInfo( + Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc); + OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc)); + ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl, + Obj, HadMultipleCandidates, + OpLocInfo.getLoc(), + OpLocInfo.getInfo()); + if (NewFn.isInvalid()) + return true; + + // The number of argument slots to allocate in the call. If we have default + // arguments we need to allocate space for them as well. We additionally + // need one more slot for the object parameter. + unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams); + + // Build the full argument list for the method call (the implicit object + // parameter is placed at the beginning of the list). + SmallVector<Expr *, 8> MethodArgs(NumArgsSlots); + + bool IsError = false; + + // Initialize the implicit object parameter. + ExprResult ObjRes = + PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr, + Best->FoundDecl, Method); + if (ObjRes.isInvalid()) + IsError = true; + else + Object = ObjRes; + MethodArgs[0] = Object.get(); + + // Check the argument types. + for (unsigned i = 0; i != NumParams; i++) { + Expr *Arg; + if (i < Args.size()) { + Arg = Args[i]; + + // Pass the argument. + + ExprResult InputInit + = PerformCopyInitialization(InitializedEntity::InitializeParameter( + Context, + Method->getParamDecl(i)), + SourceLocation(), Arg); + + IsError |= InputInit.isInvalid(); + Arg = InputInit.getAs<Expr>(); + } else { + ExprResult DefArg + = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); + if (DefArg.isInvalid()) { + IsError = true; + break; + } + + Arg = DefArg.getAs<Expr>(); + } + + MethodArgs[i + 1] = Arg; + } + + // If this is a variadic call, handle args passed through "...". + if (Proto->isVariadic()) { + // Promote the arguments (C99 6.5.2.2p7). + for (unsigned i = NumParams, e = Args.size(); i < e; i++) { + ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod, + nullptr); + IsError |= Arg.isInvalid(); + MethodArgs[i + 1] = Arg.get(); + } + } + + if (IsError) + return true; + + DiagnoseSentinelCalls(Method, LParenLoc, Args); + + // Once we've built TheCall, all of the expressions are properly owned. + QualType ResultTy = Method->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + + CXXOperatorCallExpr *TheCall = + CXXOperatorCallExpr::Create(Context, OO_Call, NewFn.get(), MethodArgs, + ResultTy, VK, RParenLoc, FPOptions()); + + if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method)) + return true; + + if (CheckFunctionCall(Method, TheCall, Proto)) + return true; + + return MaybeBindToTemporary(TheCall); +} + +/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> +/// (if one exists), where @c Base is an expression of class type and +/// @c Member is the name of the member we're trying to find. +ExprResult +Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc, + bool *NoArrowOperatorFound) { + assert(Base->getType()->isRecordType() && + "left-hand side must have class type"); + + if (checkPlaceholderForOverload(*this, Base)) + return ExprError(); + + SourceLocation Loc = Base->getExprLoc(); + + // C++ [over.ref]p1: + // + // [...] An expression x->m is interpreted as (x.operator->())->m + // for a class object x of type T if T::operator->() exists and if + // the operator is selected as the best match function by the + // overload resolution mechanism (13.3). + DeclarationName OpName = + Context.DeclarationNames.getCXXOperatorName(OO_Arrow); + OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator); + const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); + + if (RequireCompleteType(Loc, Base->getType(), + diag::err_typecheck_incomplete_tag, Base)) + return ExprError(); + + LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); + LookupQualifiedName(R, BaseRecord->getDecl()); + R.suppressDiagnostics(); + + for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); + Oper != OperEnd; ++Oper) { + AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context), + None, CandidateSet, /*SuppressUserConversions=*/false); + } + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) { + case OR_Success: + // Overload resolution succeeded; we'll build the call below. + break; + + case OR_No_Viable_Function: + if (CandidateSet.empty()) { + QualType BaseType = Base->getType(); + if (NoArrowOperatorFound) { + // Report this specific error to the caller instead of emitting a + // diagnostic, as requested. + *NoArrowOperatorFound = true; + return ExprError(); + } + Diag(OpLoc, diag::err_typecheck_member_reference_arrow) + << BaseType << Base->getSourceRange(); + if (BaseType->isRecordType() && !BaseType->isPointerType()) { + Diag(OpLoc, diag::note_typecheck_member_reference_suggestion) + << FixItHint::CreateReplacement(OpLoc, "."); + } + } else + Diag(OpLoc, diag::err_ovl_no_viable_oper) + << "operator->" << Base->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Base); + return ExprError(); + + case OR_Ambiguous: + Diag(OpLoc, diag::err_ovl_ambiguous_oper_unary) + << "->" << Base->getType() << Base->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Base); + return ExprError(); + + case OR_Deleted: + Diag(OpLoc, diag::err_ovl_deleted_oper) + << Best->Function->isDeleted() + << "->" + << getDeletedOrUnavailableSuffix(Best->Function) + << Base->getSourceRange(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Base); + return ExprError(); + } + + CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl); + + // Convert the object parameter. + CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); + ExprResult BaseResult = + PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr, + Best->FoundDecl, Method); + if (BaseResult.isInvalid()) + return ExprError(); + Base = BaseResult.get(); + + // Build the operator call. + ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl, + Base, HadMultipleCandidates, OpLoc); + if (FnExpr.isInvalid()) + return ExprError(); + + QualType ResultTy = Method->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create( + Context, OO_Arrow, FnExpr.get(), Base, ResultTy, VK, OpLoc, FPOptions()); + + if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method)) + return ExprError(); + + if (CheckFunctionCall(Method, TheCall, + Method->getType()->castAs<FunctionProtoType>())) + return ExprError(); + + return MaybeBindToTemporary(TheCall); +} + +/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to +/// a literal operator described by the provided lookup results. +ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R, + DeclarationNameInfo &SuffixInfo, + ArrayRef<Expr*> Args, + SourceLocation LitEndLoc, + TemplateArgumentListInfo *TemplateArgs) { + SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc(); + + OverloadCandidateSet CandidateSet(UDSuffixLoc, + OverloadCandidateSet::CSK_Normal); + AddFunctionCandidates(R.asUnresolvedSet(), Args, CandidateSet, TemplateArgs, + /*SuppressUserConversions=*/true); + + bool HadMultipleCandidates = (CandidateSet.size() > 1); + + // Perform overload resolution. This will usually be trivial, but might need + // to perform substitutions for a literal operator template. + OverloadCandidateSet::iterator Best; + switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) { + case OR_Success: + case OR_Deleted: + break; + + case OR_No_Viable_Function: + Diag(UDSuffixLoc, diag::err_ovl_no_viable_function_in_call) + << R.getLookupName(); + CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args); + return ExprError(); + + case OR_Ambiguous: + Diag(R.getNameLoc(), diag::err_ovl_ambiguous_call) << R.getLookupName(); + CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args); + return ExprError(); + } + + FunctionDecl *FD = Best->Function; + ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl, + nullptr, HadMultipleCandidates, + SuffixInfo.getLoc(), + SuffixInfo.getInfo()); + if (Fn.isInvalid()) + return true; + + // Check the argument types. This should almost always be a no-op, except + // that array-to-pointer decay is applied to string literals. + Expr *ConvArgs[2]; + for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) { + ExprResult InputInit = PerformCopyInitialization( + InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)), + SourceLocation(), Args[ArgIdx]); + if (InputInit.isInvalid()) + return true; + ConvArgs[ArgIdx] = InputInit.get(); + } + + QualType ResultTy = FD->getReturnType(); + ExprValueKind VK = Expr::getValueKindForType(ResultTy); + ResultTy = ResultTy.getNonLValueExprType(Context); + + UserDefinedLiteral *UDL = UserDefinedLiteral::Create( + Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy, + VK, LitEndLoc, UDSuffixLoc); + + if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD)) + return ExprError(); + + if (CheckFunctionCall(FD, UDL, nullptr)) + return ExprError(); + + return MaybeBindToTemporary(UDL); +} + +/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the +/// given LookupResult is non-empty, it is assumed to describe a member which +/// will be invoked. Otherwise, the function will be found via argument +/// dependent lookup. +/// CallExpr is set to a valid expression and FRS_Success returned on success, +/// otherwise CallExpr is set to ExprError() and some non-success value +/// is returned. +Sema::ForRangeStatus +Sema::BuildForRangeBeginEndCall(SourceLocation Loc, + SourceLocation RangeLoc, + const DeclarationNameInfo &NameInfo, + LookupResult &MemberLookup, + OverloadCandidateSet *CandidateSet, + Expr *Range, ExprResult *CallExpr) { + Scope *S = nullptr; + + CandidateSet->clear(OverloadCandidateSet::CSK_Normal); + if (!MemberLookup.empty()) { + ExprResult MemberRef = + BuildMemberReferenceExpr(Range, Range->getType(), Loc, + /*IsPtr=*/false, CXXScopeSpec(), + /*TemplateKWLoc=*/SourceLocation(), + /*FirstQualifierInScope=*/nullptr, + MemberLookup, + /*TemplateArgs=*/nullptr, S); + if (MemberRef.isInvalid()) { + *CallExpr = ExprError(); + return FRS_DiagnosticIssued; + } + *CallExpr = ActOnCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr); + if (CallExpr->isInvalid()) { + *CallExpr = ExprError(); + return FRS_DiagnosticIssued; + } + } else { + UnresolvedSet<0> FoundNames; + UnresolvedLookupExpr *Fn = + UnresolvedLookupExpr::Create(Context, /*NamingClass=*/nullptr, + NestedNameSpecifierLoc(), NameInfo, + /*NeedsADL=*/true, /*Overloaded=*/false, + FoundNames.begin(), FoundNames.end()); + + bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc, + CandidateSet, CallExpr); + if (CandidateSet->empty() || CandidateSetError) { + *CallExpr = ExprError(); + return FRS_NoViableFunction; + } + OverloadCandidateSet::iterator Best; + OverloadingResult OverloadResult = + CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best); + + if (OverloadResult == OR_No_Viable_Function) { + *CallExpr = ExprError(); + return FRS_NoViableFunction; + } + *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range, + Loc, nullptr, CandidateSet, &Best, + OverloadResult, + /*AllowTypoCorrection=*/false); + if (CallExpr->isInvalid() || OverloadResult != OR_Success) { + *CallExpr = ExprError(); + return FRS_DiagnosticIssued; + } + } + return FRS_Success; +} + + +/// FixOverloadedFunctionReference - E is an expression that refers to +/// a C++ overloaded function (possibly with some parentheses and +/// perhaps a '&' around it). We have resolved the overloaded function +/// to the function declaration Fn, so patch up the expression E to +/// refer (possibly indirectly) to Fn. Returns the new expr. +Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, + FunctionDecl *Fn) { + if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { + Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), + Found, Fn); + if (SubExpr == PE->getSubExpr()) + return PE; + + return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); + } + + if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { + Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), + Found, Fn); + assert(Context.hasSameType(ICE->getSubExpr()->getType(), + SubExpr->getType()) && + "Implicit cast type cannot be determined from overload"); + assert(ICE->path_empty() && "fixing up hierarchy conversion?"); + if (SubExpr == ICE->getSubExpr()) + return ICE; + + return ImplicitCastExpr::Create(Context, ICE->getType(), + ICE->getCastKind(), + SubExpr, nullptr, + ICE->getValueKind()); + } + + if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) { + if (!GSE->isResultDependent()) { + Expr *SubExpr = + FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn); + if (SubExpr == GSE->getResultExpr()) + return GSE; + + // Replace the resulting type information before rebuilding the generic + // selection expression. + ArrayRef<Expr *> A = GSE->getAssocExprs(); + SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end()); + unsigned ResultIdx = GSE->getResultIndex(); + AssocExprs[ResultIdx] = SubExpr; + + return new (Context) GenericSelectionExpr( + Context, GSE->getGenericLoc(), GSE->getControllingExpr(), + GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(), + GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(), + ResultIdx); + } + // Rather than fall through to the unreachable, return the original generic + // selection expression. + return GSE; + } + + if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { + assert(UnOp->getOpcode() == UO_AddrOf && + "Can only take the address of an overloaded function"); + if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { + if (Method->isStatic()) { + // Do nothing: static member functions aren't any different + // from non-member functions. + } else { + // Fix the subexpression, which really has to be an + // UnresolvedLookupExpr holding an overloaded member function + // or template. + Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), + Found, Fn); + if (SubExpr == UnOp->getSubExpr()) + return UnOp; + + assert(isa<DeclRefExpr>(SubExpr) + && "fixed to something other than a decl ref"); + assert(cast<DeclRefExpr>(SubExpr)->getQualifier() + && "fixed to a member ref with no nested name qualifier"); + + // We have taken the address of a pointer to member + // function. Perform the computation here so that we get the + // appropriate pointer to member type. + QualType ClassType + = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); + QualType MemPtrType + = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); + // Under the MS ABI, lock down the inheritance model now. + if (Context.getTargetInfo().getCXXABI().isMicrosoft()) + (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType); + + return new (Context) UnaryOperator(SubExpr, UO_AddrOf, MemPtrType, + VK_RValue, OK_Ordinary, + UnOp->getOperatorLoc(), false); + } + } + Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), + Found, Fn); + if (SubExpr == UnOp->getSubExpr()) + return UnOp; + + return new (Context) UnaryOperator(SubExpr, UO_AddrOf, + Context.getPointerType(SubExpr->getType()), + VK_RValue, OK_Ordinary, + UnOp->getOperatorLoc(), false); + } + + // C++ [except.spec]p17: + // An exception-specification is considered to be needed when: + // - in an expression the function is the unique lookup result or the + // selected member of a set of overloaded functions + if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>()) + ResolveExceptionSpec(E->getExprLoc(), FPT); + + if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { + // FIXME: avoid copy. + TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; + if (ULE->hasExplicitTemplateArgs()) { + ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); + TemplateArgs = &TemplateArgsBuffer; + } + + DeclRefExpr *DRE = DeclRefExpr::Create(Context, + ULE->getQualifierLoc(), + ULE->getTemplateKeywordLoc(), + Fn, + /*enclosing*/ false, // FIXME? + ULE->getNameLoc(), + Fn->getType(), + VK_LValue, + Found.getDecl(), + TemplateArgs); + MarkDeclRefReferenced(DRE); + DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1); + return DRE; + } + + if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { + // FIXME: avoid copy. + TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr; + if (MemExpr->hasExplicitTemplateArgs()) { + MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); + TemplateArgs = &TemplateArgsBuffer; + } + + Expr *Base; + + // If we're filling in a static method where we used to have an + // implicit member access, rewrite to a simple decl ref. + if (MemExpr->isImplicitAccess()) { + if (cast<CXXMethodDecl>(Fn)->isStatic()) { + DeclRefExpr *DRE = DeclRefExpr::Create(Context, + MemExpr->getQualifierLoc(), + MemExpr->getTemplateKeywordLoc(), + Fn, + /*enclosing*/ false, + MemExpr->getMemberLoc(), + Fn->getType(), + VK_LValue, + Found.getDecl(), + TemplateArgs); + MarkDeclRefReferenced(DRE); + DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1); + return DRE; + } else { + SourceLocation Loc = MemExpr->getMemberLoc(); + if (MemExpr->getQualifier()) + Loc = MemExpr->getQualifierLoc().getBeginLoc(); + CheckCXXThisCapture(Loc); + Base = new (Context) CXXThisExpr(Loc, + MemExpr->getBaseType(), + /*isImplicit=*/true); + } + } else + Base = MemExpr->getBase(); + + ExprValueKind valueKind; + QualType type; + if (cast<CXXMethodDecl>(Fn)->isStatic()) { + valueKind = VK_LValue; + type = Fn->getType(); + } else { + valueKind = VK_RValue; + type = Context.BoundMemberTy; + } + + MemberExpr *ME = MemberExpr::Create( + Context, Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(), + MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found, + MemExpr->getMemberNameInfo(), TemplateArgs, type, valueKind, + OK_Ordinary); + ME->setHadMultipleCandidates(true); + MarkMemberReferenced(ME); + return ME; + } + + llvm_unreachable("Invalid reference to overloaded function"); +} + +ExprResult Sema::FixOverloadedFunctionReference(ExprResult E, + DeclAccessPair Found, + FunctionDecl *Fn) { + return FixOverloadedFunctionReference(E.get(), Found, Fn); +} |