//===------- SemaTemplateDeduction.cpp - Template Argument Deduction ------===/ // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. //===----------------------------------------------------------------------===/ // // This file implements C++ template argument deduction. // //===----------------------------------------------------------------------===/ #include "clang/Sema/Sema.h" #include "clang/Sema/DeclSpec.h" #include "clang/Sema/SemaDiagnostic.h" // FIXME: temporary! #include "clang/Sema/Template.h" #include "clang/Sema/TemplateDeduction.h" #include "clang/AST/ASTContext.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/DeclTemplate.h" #include "clang/AST/StmtVisitor.h" #include "clang/AST/Expr.h" #include "clang/AST/ExprCXX.h" #include "llvm/ADT/BitVector.h" #include namespace clang { using namespace sema; /// \brief Various flags that control template argument deduction. /// /// These flags can be bitwise-OR'd together. enum TemplateDeductionFlags { /// \brief No template argument deduction flags, which indicates the /// strictest results for template argument deduction (as used for, e.g., /// matching class template partial specializations). TDF_None = 0, /// \brief Within template argument deduction from a function call, we are /// matching with a parameter type for which the original parameter was /// a reference. TDF_ParamWithReferenceType = 0x1, /// \brief Within template argument deduction from a function call, we /// are matching in a case where we ignore cv-qualifiers. TDF_IgnoreQualifiers = 0x02, /// \brief Within template argument deduction from a function call, /// we are matching in a case where we can perform template argument /// deduction from a template-id of a derived class of the argument type. TDF_DerivedClass = 0x04, /// \brief Allow non-dependent types to differ, e.g., when performing /// template argument deduction from a function call where conversions /// may apply. TDF_SkipNonDependent = 0x08 }; } using namespace clang; /// \brief Compare two APSInts, extending and switching the sign as /// necessary to compare their values regardless of underlying type. static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) { if (Y.getBitWidth() > X.getBitWidth()) X = X.extend(Y.getBitWidth()); else if (Y.getBitWidth() < X.getBitWidth()) Y = Y.extend(X.getBitWidth()); // If there is a signedness mismatch, correct it. if (X.isSigned() != Y.isSigned()) { // If the signed value is negative, then the values cannot be the same. if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative())) return false; Y.setIsSigned(true); X.setIsSigned(true); } return X == Y; } static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateArgument &Param, const TemplateArgument &Arg, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced); static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateArgument *Params, unsigned NumParams, const TemplateArgument *Args, unsigned NumArgs, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced, bool NumberOfArgumentsMustMatch = true); /// \brief If the given expression is of a form that permits the deduction /// of a non-type template parameter, return the declaration of that /// non-type template parameter. static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) { if (ImplicitCastExpr *IC = dyn_cast(E)) E = IC->getSubExpr(); if (DeclRefExpr *DRE = dyn_cast(E)) return dyn_cast(DRE->getDecl()); return 0; } /// \brief Determine whether two declaration pointers refer to the same /// declaration. static bool isSameDeclaration(Decl *X, Decl *Y) { if (!X || !Y) return !X && !Y; if (NamedDecl *NX = dyn_cast(X)) X = NX->getUnderlyingDecl(); if (NamedDecl *NY = dyn_cast(Y)) Y = NY->getUnderlyingDecl(); return X->getCanonicalDecl() == Y->getCanonicalDecl(); } /// \brief Verify that the given, deduced template arguments are compatible. /// /// \returns The deduced template argument, or a NULL template argument if /// the deduced template arguments were incompatible. static DeducedTemplateArgument checkDeducedTemplateArguments(ASTContext &Context, const DeducedTemplateArgument &X, const DeducedTemplateArgument &Y) { // We have no deduction for one or both of the arguments; they're compatible. if (X.isNull()) return Y; if (Y.isNull()) return X; switch (X.getKind()) { case TemplateArgument::Null: llvm_unreachable("Non-deduced template arguments handled above"); case TemplateArgument::Type: // If two template type arguments have the same type, they're compatible. if (Y.getKind() == TemplateArgument::Type && Context.hasSameType(X.getAsType(), Y.getAsType())) return X; return DeducedTemplateArgument(); case TemplateArgument::Integral: // If we deduced a constant in one case and either a dependent expression or // declaration in another case, keep the integral constant. // If both are integral constants with the same value, keep that value. if (Y.getKind() == TemplateArgument::Expression || Y.getKind() == TemplateArgument::Declaration || (Y.getKind() == TemplateArgument::Integral && hasSameExtendedValue(*X.getAsIntegral(), *Y.getAsIntegral()))) return DeducedTemplateArgument(X, X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound()); // All other combinations are incompatible. return DeducedTemplateArgument(); case TemplateArgument::Template: if (Y.getKind() == TemplateArgument::Template && Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate())) return X; // All other combinations are incompatible. return DeducedTemplateArgument(); case TemplateArgument::TemplateExpansion: if (Y.getKind() == TemplateArgument::TemplateExpansion && Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(), Y.getAsTemplateOrTemplatePattern())) return X; // All other combinations are incompatible. return DeducedTemplateArgument(); case TemplateArgument::Expression: // If we deduced a dependent expression in one case and either an integral // constant or a declaration in another case, keep the integral constant // or declaration. if (Y.getKind() == TemplateArgument::Integral || Y.getKind() == TemplateArgument::Declaration) return DeducedTemplateArgument(Y, X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound()); if (Y.getKind() == TemplateArgument::Expression) { // Compare the expressions for equality llvm::FoldingSetNodeID ID1, ID2; X.getAsExpr()->Profile(ID1, Context, true); Y.getAsExpr()->Profile(ID2, Context, true); if (ID1 == ID2) return X; } // All other combinations are incompatible. return DeducedTemplateArgument(); case TemplateArgument::Declaration: // If we deduced a declaration and a dependent expression, keep the // declaration. if (Y.getKind() == TemplateArgument::Expression) return X; // If we deduced a declaration and an integral constant, keep the // integral constant. if (Y.getKind() == TemplateArgument::Integral) return Y; // If we deduced two declarations, make sure they they refer to the // same declaration. if (Y.getKind() == TemplateArgument::Declaration && isSameDeclaration(X.getAsDecl(), Y.getAsDecl())) return X; // All other combinations are incompatible. return DeducedTemplateArgument(); case TemplateArgument::Pack: if (Y.getKind() != TemplateArgument::Pack || X.pack_size() != Y.pack_size()) return DeducedTemplateArgument(); for (TemplateArgument::pack_iterator XA = X.pack_begin(), XAEnd = X.pack_end(), YA = Y.pack_begin(); XA != XAEnd; ++XA, ++YA) { if (checkDeducedTemplateArguments(Context, DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()), DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound())) .isNull()) return DeducedTemplateArgument(); } return X; } return DeducedTemplateArgument(); } /// \brief Deduce the value of the given non-type template parameter /// from the given constant. static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(Sema &S, NonTypeTemplateParmDecl *NTTP, llvm::APSInt Value, QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { assert(NTTP->getDepth() == 0 && "Cannot deduce non-type template argument with depth > 0"); DeducedTemplateArgument NewDeduced(Value, ValueType, DeducedFromArrayBound); DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, Deduced[NTTP->getIndex()], NewDeduced); if (Result.isNull()) { Info.Param = NTTP; Info.FirstArg = Deduced[NTTP->getIndex()]; Info.SecondArg = NewDeduced; return Sema::TDK_Inconsistent; } Deduced[NTTP->getIndex()] = Result; return Sema::TDK_Success; } /// \brief Deduce the value of the given non-type template parameter /// from the given type- or value-dependent expression. /// /// \returns true if deduction succeeded, false otherwise. static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(Sema &S, NonTypeTemplateParmDecl *NTTP, Expr *Value, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { assert(NTTP->getDepth() == 0 && "Cannot deduce non-type template argument with depth > 0"); assert((Value->isTypeDependent() || Value->isValueDependent()) && "Expression template argument must be type- or value-dependent."); DeducedTemplateArgument NewDeduced(Value); DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, Deduced[NTTP->getIndex()], NewDeduced); if (Result.isNull()) { Info.Param = NTTP; Info.FirstArg = Deduced[NTTP->getIndex()]; Info.SecondArg = NewDeduced; return Sema::TDK_Inconsistent; } Deduced[NTTP->getIndex()] = Result; return Sema::TDK_Success; } /// \brief Deduce the value of the given non-type template parameter /// from the given declaration. /// /// \returns true if deduction succeeded, false otherwise. static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(Sema &S, NonTypeTemplateParmDecl *NTTP, Decl *D, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { assert(NTTP->getDepth() == 0 && "Cannot deduce non-type template argument with depth > 0"); DeducedTemplateArgument NewDeduced(D? D->getCanonicalDecl() : 0); DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, Deduced[NTTP->getIndex()], NewDeduced); if (Result.isNull()) { Info.Param = NTTP; Info.FirstArg = Deduced[NTTP->getIndex()]; Info.SecondArg = NewDeduced; return Sema::TDK_Inconsistent; } Deduced[NTTP->getIndex()] = Result; return Sema::TDK_Success; } static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, TemplateName Param, TemplateName Arg, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { TemplateDecl *ParamDecl = Param.getAsTemplateDecl(); if (!ParamDecl) { // The parameter type is dependent and is not a template template parameter, // so there is nothing that we can deduce. return Sema::TDK_Success; } if (TemplateTemplateParmDecl *TempParam = dyn_cast(ParamDecl)) { DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg)); DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, Deduced[TempParam->getIndex()], NewDeduced); if (Result.isNull()) { Info.Param = TempParam; Info.FirstArg = Deduced[TempParam->getIndex()]; Info.SecondArg = NewDeduced; return Sema::TDK_Inconsistent; } Deduced[TempParam->getIndex()] = Result; return Sema::TDK_Success; } // Verify that the two template names are equivalent. if (S.Context.hasSameTemplateName(Param, Arg)) return Sema::TDK_Success; // Mismatch of non-dependent template parameter to argument. Info.FirstArg = TemplateArgument(Param); Info.SecondArg = TemplateArgument(Arg); return Sema::TDK_NonDeducedMismatch; } /// \brief Deduce the template arguments by comparing the template parameter /// type (which is a template-id) with the template argument type. /// /// \param S the Sema /// /// \param TemplateParams the template parameters that we are deducing /// /// \param Param the parameter type /// /// \param Arg the argument type /// /// \param Info information about the template argument deduction itself /// /// \param Deduced the deduced template arguments /// /// \returns the result of template argument deduction so far. Note that a /// "success" result means that template argument deduction has not yet failed, /// but it may still fail, later, for other reasons. static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateSpecializationType *Param, QualType Arg, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { assert(Arg.isCanonical() && "Argument type must be canonical"); // Check whether the template argument is a dependent template-id. if (const TemplateSpecializationType *SpecArg = dyn_cast(Arg)) { // Perform template argument deduction for the template name. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, Param->getTemplateName(), SpecArg->getTemplateName(), Info, Deduced)) return Result; // Perform template argument deduction on each template // argument. Ignore any missing/extra arguments, since they could be // filled in by default arguments. return DeduceTemplateArguments(S, TemplateParams, Param->getArgs(), Param->getNumArgs(), SpecArg->getArgs(), SpecArg->getNumArgs(), Info, Deduced, /*NumberOfArgumentsMustMatch=*/false); } // If the argument type is a class template specialization, we // perform template argument deduction using its template // arguments. const RecordType *RecordArg = dyn_cast(Arg); if (!RecordArg) return Sema::TDK_NonDeducedMismatch; ClassTemplateSpecializationDecl *SpecArg = dyn_cast(RecordArg->getDecl()); if (!SpecArg) return Sema::TDK_NonDeducedMismatch; // Perform template argument deduction for the template name. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, Param->getTemplateName(), TemplateName(SpecArg->getSpecializedTemplate()), Info, Deduced)) return Result; // Perform template argument deduction for the template arguments. return DeduceTemplateArguments(S, TemplateParams, Param->getArgs(), Param->getNumArgs(), SpecArg->getTemplateArgs().data(), SpecArg->getTemplateArgs().size(), Info, Deduced); } /// \brief Determines whether the given type is an opaque type that /// might be more qualified when instantiated. static bool IsPossiblyOpaquelyQualifiedType(QualType T) { switch (T->getTypeClass()) { case Type::TypeOfExpr: case Type::TypeOf: case Type::DependentName: case Type::Decltype: case Type::UnresolvedUsing: return true; case Type::ConstantArray: case Type::IncompleteArray: case Type::VariableArray: case Type::DependentSizedArray: return IsPossiblyOpaquelyQualifiedType( cast(T)->getElementType()); default: return false; } } /// \brief Deduce the template arguments by comparing the parameter type and /// the argument type (C++ [temp.deduct.type]). /// /// \param S the semantic analysis object within which we are deducing /// /// \param TemplateParams the template parameters that we are deducing /// /// \param ParamIn the parameter type /// /// \param ArgIn the argument type /// /// \param Info information about the template argument deduction itself /// /// \param Deduced the deduced template arguments /// /// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe /// how template argument deduction is performed. /// /// \returns the result of template argument deduction so far. Note that a /// "success" result means that template argument deduction has not yet failed, /// but it may still fail, later, for other reasons. static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, QualType ParamIn, QualType ArgIn, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced, unsigned TDF) { // We only want to look at the canonical types, since typedefs and // sugar are not part of template argument deduction. QualType Param = S.Context.getCanonicalType(ParamIn); QualType Arg = S.Context.getCanonicalType(ArgIn); // C++0x [temp.deduct.call]p4 bullet 1: // - If the original P is a reference type, the deduced A (i.e., the type // referred to by the reference) can be more cv-qualified than the // transformed A. if (TDF & TDF_ParamWithReferenceType) { Qualifiers Quals; QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals); Quals.setCVRQualifiers(Quals.getCVRQualifiers() & Arg.getCVRQualifiersThroughArrayTypes()); Param = S.Context.getQualifiedType(UnqualParam, Quals); } // If the parameter type is not dependent, there is nothing to deduce. if (!Param->isDependentType()) { if (!(TDF & TDF_SkipNonDependent) && Param != Arg) { return Sema::TDK_NonDeducedMismatch; } return Sema::TDK_Success; } // C++ [temp.deduct.type]p9: // A template type argument T, a template template argument TT or a // template non-type argument i can be deduced if P and A have one of // the following forms: // // T // cv-list T if (const TemplateTypeParmType *TemplateTypeParm = Param->getAs()) { unsigned Index = TemplateTypeParm->getIndex(); bool RecanonicalizeArg = false; // If the argument type is an array type, move the qualifiers up to the // top level, so they can be matched with the qualifiers on the parameter. // FIXME: address spaces, ObjC GC qualifiers if (isa(Arg)) { Qualifiers Quals; Arg = S.Context.getUnqualifiedArrayType(Arg, Quals); if (Quals) { Arg = S.Context.getQualifiedType(Arg, Quals); RecanonicalizeArg = true; } } // The argument type can not be less qualified than the parameter // type. if (Param.isMoreQualifiedThan(Arg) && !(TDF & TDF_IgnoreQualifiers)) { Info.Param = cast(TemplateParams->getParam(Index)); Info.FirstArg = TemplateArgument(Param); Info.SecondArg = TemplateArgument(Arg); return Sema::TDK_Underqualified; } assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0"); assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function"); QualType DeducedType = Arg; // local manipulation is okay because it's canonical DeducedType.removeLocalCVRQualifiers(Param.getCVRQualifiers()); if (RecanonicalizeArg) DeducedType = S.Context.getCanonicalType(DeducedType); DeducedTemplateArgument NewDeduced(DeducedType); DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, Deduced[Index], NewDeduced); if (Result.isNull()) { Info.Param = cast(TemplateParams->getParam(Index)); Info.FirstArg = Deduced[Index]; Info.SecondArg = NewDeduced; return Sema::TDK_Inconsistent; } Deduced[Index] = Result; return Sema::TDK_Success; } // Set up the template argument deduction information for a failure. Info.FirstArg = TemplateArgument(ParamIn); Info.SecondArg = TemplateArgument(ArgIn); // Check the cv-qualifiers on the parameter and argument types. if (!(TDF & TDF_IgnoreQualifiers)) { if (TDF & TDF_ParamWithReferenceType) { if (Param.isMoreQualifiedThan(Arg)) return Sema::TDK_NonDeducedMismatch; } else if (!IsPossiblyOpaquelyQualifiedType(Param)) { if (Param.getCVRQualifiers() != Arg.getCVRQualifiers()) return Sema::TDK_NonDeducedMismatch; } } switch (Param->getTypeClass()) { // No deduction possible for these types case Type::Builtin: return Sema::TDK_NonDeducedMismatch; // T * case Type::Pointer: { QualType PointeeType; if (const PointerType *PointerArg = Arg->getAs()) { PointeeType = PointerArg->getPointeeType(); } else if (const ObjCObjectPointerType *PointerArg = Arg->getAs()) { PointeeType = PointerArg->getPointeeType(); } else { return Sema::TDK_NonDeducedMismatch; } unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass); return DeduceTemplateArguments(S, TemplateParams, cast(Param)->getPointeeType(), PointeeType, Info, Deduced, SubTDF); } // T & case Type::LValueReference: { const LValueReferenceType *ReferenceArg = Arg->getAs(); if (!ReferenceArg) return Sema::TDK_NonDeducedMismatch; return DeduceTemplateArguments(S, TemplateParams, cast(Param)->getPointeeType(), ReferenceArg->getPointeeType(), Info, Deduced, 0); } // T && [C++0x] case Type::RValueReference: { const RValueReferenceType *ReferenceArg = Arg->getAs(); if (!ReferenceArg) return Sema::TDK_NonDeducedMismatch; return DeduceTemplateArguments(S, TemplateParams, cast(Param)->getPointeeType(), ReferenceArg->getPointeeType(), Info, Deduced, 0); } // T [] (implied, but not stated explicitly) case Type::IncompleteArray: { const IncompleteArrayType *IncompleteArrayArg = S.Context.getAsIncompleteArrayType(Arg); if (!IncompleteArrayArg) return Sema::TDK_NonDeducedMismatch; unsigned SubTDF = TDF & TDF_IgnoreQualifiers; return DeduceTemplateArguments(S, TemplateParams, S.Context.getAsIncompleteArrayType(Param)->getElementType(), IncompleteArrayArg->getElementType(), Info, Deduced, SubTDF); } // T [integer-constant] case Type::ConstantArray: { const ConstantArrayType *ConstantArrayArg = S.Context.getAsConstantArrayType(Arg); if (!ConstantArrayArg) return Sema::TDK_NonDeducedMismatch; const ConstantArrayType *ConstantArrayParm = S.Context.getAsConstantArrayType(Param); if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) return Sema::TDK_NonDeducedMismatch; unsigned SubTDF = TDF & TDF_IgnoreQualifiers; return DeduceTemplateArguments(S, TemplateParams, ConstantArrayParm->getElementType(), ConstantArrayArg->getElementType(), Info, Deduced, SubTDF); } // type [i] case Type::DependentSizedArray: { const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg); if (!ArrayArg) return Sema::TDK_NonDeducedMismatch; unsigned SubTDF = TDF & TDF_IgnoreQualifiers; // Check the element type of the arrays const DependentSizedArrayType *DependentArrayParm = S.Context.getAsDependentSizedArrayType(Param); if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, DependentArrayParm->getElementType(), ArrayArg->getElementType(), Info, Deduced, SubTDF)) return Result; // Determine the array bound is something we can deduce. NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr()); if (!NTTP) return Sema::TDK_Success; // We can perform template argument deduction for the given non-type // template parameter. assert(NTTP->getDepth() == 0 && "Cannot deduce non-type template argument at depth > 0"); if (const ConstantArrayType *ConstantArrayArg = dyn_cast(ArrayArg)) { llvm::APSInt Size(ConstantArrayArg->getSize()); return DeduceNonTypeTemplateArgument(S, NTTP, Size, S.Context.getSizeType(), /*ArrayBound=*/true, Info, Deduced); } if (const DependentSizedArrayType *DependentArrayArg = dyn_cast(ArrayArg)) if (DependentArrayArg->getSizeExpr()) return DeduceNonTypeTemplateArgument(S, NTTP, DependentArrayArg->getSizeExpr(), Info, Deduced); // Incomplete type does not match a dependently-sized array type return Sema::TDK_NonDeducedMismatch; } // type(*)(T) // T(*)() // T(*)(T) case Type::FunctionProto: { const FunctionProtoType *FunctionProtoArg = dyn_cast(Arg); if (!FunctionProtoArg) return Sema::TDK_NonDeducedMismatch; const FunctionProtoType *FunctionProtoParam = cast(Param); if (FunctionProtoParam->getTypeQuals() != FunctionProtoArg->getTypeQuals()) return Sema::TDK_NonDeducedMismatch; if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs()) return Sema::TDK_NonDeducedMismatch; if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) return Sema::TDK_NonDeducedMismatch; // Check return types. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, FunctionProtoParam->getResultType(), FunctionProtoArg->getResultType(), Info, Deduced, 0)) return Result; for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) { // Check argument types. // FIXME: Variadic templates. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, FunctionProtoParam->getArgType(I), FunctionProtoArg->getArgType(I), Info, Deduced, 0)) return Result; } return Sema::TDK_Success; } case Type::InjectedClassName: { // Treat a template's injected-class-name as if the template // specialization type had been used. Param = cast(Param) ->getInjectedSpecializationType(); assert(isa(Param) && "injected class name is not a template specialization type"); // fall through } // template-name (where template-name refers to a class template) // template-name // TT // TT // TT<> case Type::TemplateSpecialization: { const TemplateSpecializationType *SpecParam = cast(Param); // Try to deduce template arguments from the template-id. Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info, Deduced); if (Result && (TDF & TDF_DerivedClass)) { // C++ [temp.deduct.call]p3b3: // If P is a class, and P has the form template-id, then A can be a // derived class of the deduced A. Likewise, if P is a pointer to a // class of the form template-id, A can be a pointer to a derived // class pointed to by the deduced A. // // More importantly: // These alternatives are considered only if type deduction would // otherwise fail. if (const RecordType *RecordT = Arg->getAs()) { // We cannot inspect base classes as part of deduction when the type // is incomplete, so either instantiate any templates necessary to // complete the type, or skip over it if it cannot be completed. if (S.RequireCompleteType(Info.getLocation(), Arg, 0)) return Result; // Use data recursion to crawl through the list of base classes. // Visited contains the set of nodes we have already visited, while // ToVisit is our stack of records that we still need to visit. llvm::SmallPtrSet Visited; llvm::SmallVector ToVisit; ToVisit.push_back(RecordT); bool Successful = false; llvm::SmallVectorImpl DeducedOrig(0); DeducedOrig = Deduced; while (!ToVisit.empty()) { // Retrieve the next class in the inheritance hierarchy. const RecordType *NextT = ToVisit.back(); ToVisit.pop_back(); // If we have already seen this type, skip it. if (!Visited.insert(NextT)) continue; // If this is a base class, try to perform template argument // deduction from it. if (NextT != RecordT) { Sema::TemplateDeductionResult BaseResult = DeduceTemplateArguments(S, TemplateParams, SpecParam, QualType(NextT, 0), Info, Deduced); // If template argument deduction for this base was successful, // note that we had some success. Otherwise, ignore any deductions // from this base class. if (BaseResult == Sema::TDK_Success) { Successful = true; DeducedOrig = Deduced; } else Deduced = DeducedOrig; } // Visit base classes CXXRecordDecl *Next = cast(NextT->getDecl()); for (CXXRecordDecl::base_class_iterator Base = Next->bases_begin(), BaseEnd = Next->bases_end(); Base != BaseEnd; ++Base) { assert(Base->getType()->isRecordType() && "Base class that isn't a record?"); ToVisit.push_back(Base->getType()->getAs()); } } if (Successful) return Sema::TDK_Success; } } return Result; } // T type::* // T T::* // T (type::*)() // type (T::*)() // type (type::*)(T) // type (T::*)(T) // T (type::*)(T) // T (T::*)() // T (T::*)(T) case Type::MemberPointer: { const MemberPointerType *MemPtrParam = cast(Param); const MemberPointerType *MemPtrArg = dyn_cast(Arg); if (!MemPtrArg) return Sema::TDK_NonDeducedMismatch; if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, MemPtrParam->getPointeeType(), MemPtrArg->getPointeeType(), Info, Deduced, TDF & TDF_IgnoreQualifiers)) return Result; return DeduceTemplateArguments(S, TemplateParams, QualType(MemPtrParam->getClass(), 0), QualType(MemPtrArg->getClass(), 0), Info, Deduced, 0); } // (clang extension) // // type(^)(T) // T(^)() // T(^)(T) case Type::BlockPointer: { const BlockPointerType *BlockPtrParam = cast(Param); const BlockPointerType *BlockPtrArg = dyn_cast(Arg); if (!BlockPtrArg) return Sema::TDK_NonDeducedMismatch; return DeduceTemplateArguments(S, TemplateParams, BlockPtrParam->getPointeeType(), BlockPtrArg->getPointeeType(), Info, Deduced, 0); } case Type::TypeOfExpr: case Type::TypeOf: case Type::DependentName: // No template argument deduction for these types return Sema::TDK_Success; default: break; } // FIXME: Many more cases to go (to go). return Sema::TDK_Success; } static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateArgument &Param, const TemplateArgument &Arg, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { switch (Param.getKind()) { case TemplateArgument::Null: assert(false && "Null template argument in parameter list"); break; case TemplateArgument::Type: if (Arg.getKind() == TemplateArgument::Type) return DeduceTemplateArguments(S, TemplateParams, Param.getAsType(), Arg.getAsType(), Info, Deduced, 0); Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; case TemplateArgument::Template: if (Arg.getKind() == TemplateArgument::Template) return DeduceTemplateArguments(S, TemplateParams, Param.getAsTemplate(), Arg.getAsTemplate(), Info, Deduced); Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; case TemplateArgument::TemplateExpansion: llvm_unreachable("caller should handle pack expansions"); break; case TemplateArgument::Declaration: if (Arg.getKind() == TemplateArgument::Declaration && Param.getAsDecl()->getCanonicalDecl() == Arg.getAsDecl()->getCanonicalDecl()) return Sema::TDK_Success; Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; case TemplateArgument::Integral: if (Arg.getKind() == TemplateArgument::Integral) { if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral())) return Sema::TDK_Success; Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; } if (Arg.getKind() == TemplateArgument::Expression) { Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; } Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; case TemplateArgument::Expression: { if (NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(Param.getAsExpr())) { if (Arg.getKind() == TemplateArgument::Integral) return DeduceNonTypeTemplateArgument(S, NTTP, *Arg.getAsIntegral(), Arg.getIntegralType(), /*ArrayBound=*/false, Info, Deduced); if (Arg.getKind() == TemplateArgument::Expression) return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(), Info, Deduced); if (Arg.getKind() == TemplateArgument::Declaration) return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(), Info, Deduced); Info.FirstArg = Param; Info.SecondArg = Arg; return Sema::TDK_NonDeducedMismatch; } // Can't deduce anything, but that's okay. return Sema::TDK_Success; } case TemplateArgument::Pack: llvm_unreachable("Argument packs should be expanded by the caller!"); } return Sema::TDK_Success; } /// \brief Determine whether there is a template argument to be used for /// deduction. /// /// This routine "expands" argument packs in-place, overriding its input /// parameters so that \c Args[ArgIdx] will be the available template argument. /// /// \returns true if there is another template argument (which will be at /// \c Args[ArgIdx]), false otherwise. static bool hasTemplateArgumentForDeduction(const TemplateArgument *&Args, unsigned &ArgIdx, unsigned &NumArgs) { if (ArgIdx == NumArgs) return false; const TemplateArgument &Arg = Args[ArgIdx]; if (Arg.getKind() != TemplateArgument::Pack) return true; assert(ArgIdx == NumArgs - 1 && "Pack not at the end of argument list?"); Args = Arg.pack_begin(); NumArgs = Arg.pack_size(); ArgIdx = 0; return ArgIdx < NumArgs; } /// \brief Retrieve the depth and index of an unexpanded parameter pack. static std::pair getDepthAndIndex(UnexpandedParameterPack UPP) { if (const TemplateTypeParmType *TTP = UPP.first.dyn_cast()) return std::make_pair(TTP->getDepth(), TTP->getIndex()); NamedDecl *ND = UPP.first.get(); if (TemplateTypeParmDecl *TTP = dyn_cast(ND)) return std::make_pair(TTP->getDepth(), TTP->getIndex()); if (NonTypeTemplateParmDecl *NTTP = dyn_cast(ND)) return std::make_pair(NTTP->getDepth(), NTTP->getIndex()); TemplateTemplateParmDecl *TTP = cast(ND); return std::make_pair(TTP->getDepth(), TTP->getIndex()); } /// \brief Helper function to build a TemplateParameter when we don't /// know its type statically. static TemplateParameter makeTemplateParameter(Decl *D) { if (TemplateTypeParmDecl *TTP = dyn_cast(D)) return TemplateParameter(TTP); else if (NonTypeTemplateParmDecl *NTTP = dyn_cast(D)) return TemplateParameter(NTTP); return TemplateParameter(cast(D)); } /// \brief Determine whether the given set of template arguments has a pack /// expansion that is not the last template argument. static bool hasPackExpansionBeforeEnd(const TemplateArgument *Args, unsigned NumArgs) { unsigned ArgIdx = 0; while (ArgIdx < NumArgs) { const TemplateArgument &Arg = Args[ArgIdx]; // Unwrap argument packs. if (Args[ArgIdx].getKind() == TemplateArgument::Pack) { Args = Arg.pack_begin(); NumArgs = Arg.pack_size(); ArgIdx = 0; continue; } ++ArgIdx; if (ArgIdx == NumArgs) return false; if (Arg.isPackExpansion()) return true; } return false; } static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateArgument *Params, unsigned NumParams, const TemplateArgument *Args, unsigned NumArgs, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced, bool NumberOfArgumentsMustMatch) { // C++0x [temp.deduct.type]p9: // If the template argument list of P contains a pack expansion that is not // the last template argument, the entire template argument list is a // non-deduced context. if (hasPackExpansionBeforeEnd(Params, NumParams)) return Sema::TDK_Success; // C++0x [temp.deduct.type]p9: // If P has a form that contains or , then each argument Pi of the // respective template argument list P is compared with the corresponding // argument Ai of the corresponding template argument list of A. unsigned ArgIdx = 0, ParamIdx = 0; for (; hasTemplateArgumentForDeduction(Params, ParamIdx, NumParams); ++ParamIdx) { // FIXME: Variadic templates. // What do we do if the argument is a pack expansion? if (!Params[ParamIdx].isPackExpansion()) { // The simple case: deduce template arguments by matching Pi and Ai. // Check whether we have enough arguments. if (!hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) return NumberOfArgumentsMustMatch? Sema::TDK_TooFewArguments : Sema::TDK_Success; // Perform deduction for this Pi/Ai pair. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, Params[ParamIdx], Args[ArgIdx], Info, Deduced)) return Result; // Move to the next argument. ++ArgIdx; continue; } // The parameter is a pack expansion. // C++0x [temp.deduct.type]p9: // If Pi is a pack expansion, then the pattern of Pi is compared with // each remaining argument in the template argument list of A. Each // comparison deduces template arguments for subsequent positions in the // template parameter packs expanded by Pi. TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern(); // Compute the set of template parameter indices that correspond to // parameter packs expanded by the pack expansion. llvm::SmallVector PackIndices; { llvm::BitVector SawIndices(TemplateParams->size()); llvm::SmallVector Unexpanded; S.collectUnexpandedParameterPacks(Pattern, Unexpanded); for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { unsigned Depth, Index; llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); if (Depth == 0 && !SawIndices[Index]) { SawIndices[Index] = true; PackIndices.push_back(Index); } } } assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); // FIXME: If there are no remaining arguments, we can bail out early // and set any deduced parameter packs to an empty argument pack. // The latter part of this is a (minor) correctness issue. // Save the deduced template arguments for each parameter pack expanded // by this pack expansion, then clear out the deduction. llvm::SmallVector SavedPacks(PackIndices.size()); for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { SavedPacks[I] = Deduced[PackIndices[I]]; Deduced[PackIndices[I]] = DeducedTemplateArgument(); } // Keep track of the deduced template arguments for each parameter pack // expanded by this pack expansion (the outer index) and for each // template argument (the inner SmallVectors). llvm::SmallVector, 2> NewlyDeducedPacks(PackIndices.size()); bool HasAnyArguments = false; while (hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) { HasAnyArguments = true; // Deduce template arguments from the pattern. if (Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx], Info, Deduced)) return Result; // Capture the deduced template arguments for each parameter pack expanded // by this pack expansion, add them to the list of arguments we've deduced // for that pack, then clear out the deduced argument. for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; if (!DeducedArg.isNull()) { NewlyDeducedPacks[I].push_back(DeducedArg); DeducedArg = DeducedTemplateArgument(); } } ++ArgIdx; } // Build argument packs for each of the parameter packs expanded by this // pack expansion. for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { if (HasAnyArguments && NewlyDeducedPacks[I].empty()) { // We were not able to deduce anything for this parameter pack, // so just restore the saved argument pack. Deduced[PackIndices[I]] = SavedPacks[I]; continue; } DeducedTemplateArgument NewPack; if (NewlyDeducedPacks[I].empty()) { // If we deduced an empty argument pack, create it now. NewPack = DeducedTemplateArgument(TemplateArgument(0, 0)); } else { TemplateArgument *ArgumentPack = new (S.Context) TemplateArgument [NewlyDeducedPacks[I].size()]; std::copy(NewlyDeducedPacks[I].begin(), NewlyDeducedPacks[I].end(), ArgumentPack); NewPack = DeducedTemplateArgument(TemplateArgument(ArgumentPack, NewlyDeducedPacks[I].size()), NewlyDeducedPacks[I][0].wasDeducedFromArrayBound()); } DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, SavedPacks[I], NewPack); if (Result.isNull()) { Info.Param = makeTemplateParameter(TemplateParams->getParam(PackIndices[I])); Info.FirstArg = SavedPacks[I]; Info.SecondArg = NewPack; return Sema::TDK_Inconsistent; } Deduced[PackIndices[I]] = Result; } } // If there is an argument remaining, then we had too many arguments. if (NumberOfArgumentsMustMatch && hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) return Sema::TDK_TooManyArguments; return Sema::TDK_Success; } static Sema::TemplateDeductionResult DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, const TemplateArgumentList &ParamList, const TemplateArgumentList &ArgList, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced) { return DeduceTemplateArguments(S, TemplateParams, ParamList.data(), ParamList.size(), ArgList.data(), ArgList.size(), Info, Deduced); } /// \brief Determine whether two template arguments are the same. static bool isSameTemplateArg(ASTContext &Context, const TemplateArgument &X, const TemplateArgument &Y) { if (X.getKind() != Y.getKind()) return false; switch (X.getKind()) { case TemplateArgument::Null: assert(false && "Comparing NULL template argument"); break; case TemplateArgument::Type: return Context.getCanonicalType(X.getAsType()) == Context.getCanonicalType(Y.getAsType()); case TemplateArgument::Declaration: return X.getAsDecl()->getCanonicalDecl() == Y.getAsDecl()->getCanonicalDecl(); case TemplateArgument::Template: case TemplateArgument::TemplateExpansion: return Context.getCanonicalTemplateName( X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() == Context.getCanonicalTemplateName( Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer(); case TemplateArgument::Integral: return *X.getAsIntegral() == *Y.getAsIntegral(); case TemplateArgument::Expression: { llvm::FoldingSetNodeID XID, YID; X.getAsExpr()->Profile(XID, Context, true); Y.getAsExpr()->Profile(YID, Context, true); return XID == YID; } case TemplateArgument::Pack: if (X.pack_size() != Y.pack_size()) return false; for (TemplateArgument::pack_iterator XP = X.pack_begin(), XPEnd = X.pack_end(), YP = Y.pack_begin(); XP != XPEnd; ++XP, ++YP) if (!isSameTemplateArg(Context, *XP, *YP)) return false; return true; } return false; } /// \brief Allocate a TemplateArgumentLoc where all locations have /// been initialized to the given location. /// /// \param S The semantic analysis object. /// /// \param The template argument we are producing template argument /// location information for. /// /// \param NTTPType For a declaration template argument, the type of /// the non-type template parameter that corresponds to this template /// argument. /// /// \param Loc The source location to use for the resulting template /// argument. static TemplateArgumentLoc getTrivialTemplateArgumentLoc(Sema &S, const TemplateArgument &Arg, QualType NTTPType, SourceLocation Loc) { switch (Arg.getKind()) { case TemplateArgument::Null: llvm_unreachable("Can't get a NULL template argument here"); break; case TemplateArgument::Type: return TemplateArgumentLoc(Arg, S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); case TemplateArgument::Declaration: { Expr *E = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) .takeAs(); return TemplateArgumentLoc(TemplateArgument(E), E); } case TemplateArgument::Integral: { Expr *E = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs(); return TemplateArgumentLoc(TemplateArgument(E), E); } case TemplateArgument::Template: return TemplateArgumentLoc(Arg, SourceRange(), Loc); case TemplateArgument::TemplateExpansion: return TemplateArgumentLoc(Arg, SourceRange(), Loc, Loc); case TemplateArgument::Expression: return TemplateArgumentLoc(Arg, Arg.getAsExpr()); case TemplateArgument::Pack: return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo()); } return TemplateArgumentLoc(); } /// \brief Convert the given deduced template argument and add it to the set of /// fully-converted template arguments. static bool ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param, DeducedTemplateArgument Arg, NamedDecl *Template, QualType NTTPType, TemplateDeductionInfo &Info, bool InFunctionTemplate, llvm::SmallVectorImpl &Output) { if (Arg.getKind() == TemplateArgument::Pack) { // This is a template argument pack, so check each of its arguments against // the template parameter. llvm::SmallVector PackedArgsBuilder; for (TemplateArgument::pack_iterator PA = Arg.pack_begin(), PAEnd = Arg.pack_end(); PA != PAEnd; ++PA) { // When converting the deduced template argument, append it to the // general output list. We need to do this so that the template argument // checking logic has all of the prior template arguments available. DeducedTemplateArgument InnerArg(*PA); InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound()); if (ConvertDeducedTemplateArgument(S, Param, InnerArg, Template, NTTPType, Info, InFunctionTemplate, Output)) return true; // Move the converted template argument into our argument pack. PackedArgsBuilder.push_back(Output.back()); Output.pop_back(); } // Create the resulting argument pack. TemplateArgument *PackedArgs = 0; if (!PackedArgsBuilder.empty()) { PackedArgs = new (S.Context) TemplateArgument[PackedArgsBuilder.size()]; std::copy(PackedArgsBuilder.begin(), PackedArgsBuilder.end(), PackedArgs); } Output.push_back(TemplateArgument(PackedArgs, PackedArgsBuilder.size())); return false; } // Convert the deduced template argument into a template // argument that we can check, almost as if the user had written // the template argument explicitly. TemplateArgumentLoc ArgLoc = getTrivialTemplateArgumentLoc(S, Arg, NTTPType, Info.getLocation()); // Check the template argument, converting it as necessary. return S.CheckTemplateArgument(Param, ArgLoc, Template, Template->getLocation(), Template->getSourceRange().getEnd(), Output, InFunctionTemplate ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound : Sema::CTAK_Deduced) : Sema::CTAK_Specified); } /// Complete template argument deduction for a class template partial /// specialization. static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction(Sema &S, ClassTemplatePartialSpecializationDecl *Partial, const TemplateArgumentList &TemplateArgs, llvm::SmallVectorImpl &Deduced, TemplateDeductionInfo &Info) { // Trap errors. Sema::SFINAETrap Trap(S); Sema::ContextRAII SavedContext(S, Partial); // C++ [temp.deduct.type]p2: // [...] or if any template argument remains neither deduced nor // explicitly specified, template argument deduction fails. llvm::SmallVector Builder; TemplateParameterList *PartialParams = Partial->getTemplateParameters(); for (unsigned I = 0, N = PartialParams->size(); I != N; ++I) { NamedDecl *Param = PartialParams->getParam(I); if (Deduced[I].isNull()) { Info.Param = makeTemplateParameter(Param); return Sema::TDK_Incomplete; } // We have deduced this argument, so it still needs to be // checked and converted. // First, for a non-type template parameter type that is // initialized by a declaration, we need the type of the // corresponding non-type template parameter. QualType NTTPType; if (NonTypeTemplateParmDecl *NTTP = dyn_cast(Param)) { NTTPType = NTTP->getType(); if (NTTPType->isDependentType()) { TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Builder.data(), Builder.size()); NTTPType = S.SubstType(NTTPType, MultiLevelTemplateArgumentList(TemplateArgs), NTTP->getLocation(), NTTP->getDeclName()); if (NTTPType.isNull()) { Info.Param = makeTemplateParameter(Param); // FIXME: These template arguments are temporary. Free them! Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder.data(), Builder.size())); return Sema::TDK_SubstitutionFailure; } } } if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Partial, NTTPType, Info, false, Builder)) { Info.Param = makeTemplateParameter(Param); // FIXME: These template arguments are temporary. Free them! Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder.data(), Builder.size())); return Sema::TDK_SubstitutionFailure; } } // Form the template argument list from the deduced template arguments. TemplateArgumentList *DeducedArgumentList = TemplateArgumentList::CreateCopy(S.Context, Builder.data(), Builder.size()); Info.reset(DeducedArgumentList); // Substitute the deduced template arguments into the template // arguments of the class template partial specialization, and // verify that the instantiated template arguments are both valid // and are equivalent to the template arguments originally provided // to the class template. LocalInstantiationScope InstScope(S); ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); const TemplateArgumentLoc *PartialTemplateArgs = Partial->getTemplateArgsAsWritten(); // Note that we don't provide the langle and rangle locations. TemplateArgumentListInfo InstArgs; if (S.Subst(PartialTemplateArgs, Partial->getNumTemplateArgsAsWritten(), InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) { unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx; if (ParamIdx >= Partial->getTemplateParameters()->size()) ParamIdx = Partial->getTemplateParameters()->size() - 1; Decl *Param = const_cast( Partial->getTemplateParameters()->getParam(ParamIdx)); Info.Param = makeTemplateParameter(Param); Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument(); return Sema::TDK_SubstitutionFailure; } llvm::SmallVector ConvertedInstArgs; if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), InstArgs, false, ConvertedInstArgs)) return Sema::TDK_SubstitutionFailure; TemplateParameterList *TemplateParams = ClassTemplate->getTemplateParameters(); for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) { TemplateArgument InstArg = ConvertedInstArgs.data()[I]; if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { Info.Param = makeTemplateParameter(TemplateParams->getParam(I)); Info.FirstArg = TemplateArgs[I]; Info.SecondArg = InstArg; return Sema::TDK_NonDeducedMismatch; } } if (Trap.hasErrorOccurred()) return Sema::TDK_SubstitutionFailure; return Sema::TDK_Success; } /// \brief Perform template argument deduction to determine whether /// the given template arguments match the given class template /// partial specialization per C++ [temp.class.spec.match]. Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, const TemplateArgumentList &TemplateArgs, TemplateDeductionInfo &Info) { // C++ [temp.class.spec.match]p2: // A partial specialization matches a given actual template // argument list if the template arguments of the partial // specialization can be deduced from the actual template argument // list (14.8.2). SFINAETrap Trap(*this); llvm::SmallVector Deduced; Deduced.resize(Partial->getTemplateParameters()->size()); if (TemplateDeductionResult Result = ::DeduceTemplateArguments(*this, Partial->getTemplateParameters(), Partial->getTemplateArgs(), TemplateArgs, Info, Deduced)) return Result; InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, Deduced.data(), Deduced.size(), Info); if (Inst) return TDK_InstantiationDepth; if (Trap.hasErrorOccurred()) return Sema::TDK_SubstitutionFailure; return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs, Deduced, Info); } /// \brief Determine whether the given type T is a simple-template-id type. static bool isSimpleTemplateIdType(QualType T) { if (const TemplateSpecializationType *Spec = T->getAs()) return Spec->getTemplateName().getAsTemplateDecl() != 0; return false; } /// \brief Substitute the explicitly-provided template arguments into the /// given function template according to C++ [temp.arg.explicit]. /// /// \param FunctionTemplate the function template into which the explicit /// template arguments will be substituted. /// /// \param ExplicitTemplateArguments the explicitly-specified template /// arguments. /// /// \param Deduced the deduced template arguments, which will be populated /// with the converted and checked explicit template arguments. /// /// \param ParamTypes will be populated with the instantiated function /// parameters. /// /// \param FunctionType if non-NULL, the result type of the function template /// will also be instantiated and the pointed-to value will be updated with /// the instantiated function type. /// /// \param Info if substitution fails for any reason, this object will be /// populated with more information about the failure. /// /// \returns TDK_Success if substitution was successful, or some failure /// condition. Sema::TemplateDeductionResult Sema::SubstituteExplicitTemplateArguments( FunctionTemplateDecl *FunctionTemplate, const TemplateArgumentListInfo &ExplicitTemplateArgs, llvm::SmallVectorImpl &Deduced, llvm::SmallVectorImpl &ParamTypes, QualType *FunctionType, TemplateDeductionInfo &Info) { FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); if (ExplicitTemplateArgs.size() == 0) { // No arguments to substitute; just copy over the parameter types and // fill in the function type. for (FunctionDecl::param_iterator P = Function->param_begin(), PEnd = Function->param_end(); P != PEnd; ++P) ParamTypes.push_back((*P)->getType()); if (FunctionType) *FunctionType = Function->getType(); return TDK_Success; } // Substitution of the explicit template arguments into a function template /// is a SFINAE context. Trap any errors that might occur. SFINAETrap Trap(*this); // C++ [temp.arg.explicit]p3: // Template arguments that are present shall be specified in the // declaration order of their corresponding template-parameters. The // template argument list shall not specify more template-arguments than // there are corresponding template-parameters. llvm::SmallVector Builder; // Enter a new template instantiation context where we check the // explicitly-specified template arguments against this function template, // and then substitute them into the function parameter types. InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), FunctionTemplate, Deduced.data(), Deduced.size(), ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution, Info); if (Inst) return TDK_InstantiationDepth; if (CheckTemplateArgumentList(FunctionTemplate, SourceLocation(), ExplicitTemplateArgs, true, Builder) || Trap.hasErrorOccurred()) { unsigned Index = Builder.size(); if (Index >= TemplateParams->size()) Index = TemplateParams->size() - 1; Info.Param = makeTemplateParameter(TemplateParams->getParam(Index)); return TDK_InvalidExplicitArguments; } // Form the template argument list from the explicitly-specified // template arguments. TemplateArgumentList *ExplicitArgumentList = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); Info.reset(ExplicitArgumentList); // Template argument deduction and the final substitution should be // done in the context of the templated declaration. Explicit // argument substitution, on the other hand, needs to happen in the // calling context. ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); // Instantiate the types of each of the function parameters given the // explicitly-specified template arguments. for (FunctionDecl::param_iterator P = Function->param_begin(), PEnd = Function->param_end(); P != PEnd; ++P) { QualType ParamType = SubstType((*P)->getType(), MultiLevelTemplateArgumentList(*ExplicitArgumentList), (*P)->getLocation(), (*P)->getDeclName()); if (ParamType.isNull() || Trap.hasErrorOccurred()) return TDK_SubstitutionFailure; ParamTypes.push_back(ParamType); } // If the caller wants a full function type back, instantiate the return // type and form that function type. if (FunctionType) { // FIXME: exception-specifications? const FunctionProtoType *Proto = Function->getType()->getAs(); assert(Proto && "Function template does not have a prototype?"); QualType ResultType = SubstType(Proto->getResultType(), MultiLevelTemplateArgumentList(*ExplicitArgumentList), Function->getTypeSpecStartLoc(), Function->getDeclName()); if (ResultType.isNull() || Trap.hasErrorOccurred()) return TDK_SubstitutionFailure; *FunctionType = BuildFunctionType(ResultType, ParamTypes.data(), ParamTypes.size(), Proto->isVariadic(), Proto->getTypeQuals(), Function->getLocation(), Function->getDeclName(), Proto->getExtInfo()); if (FunctionType->isNull() || Trap.hasErrorOccurred()) return TDK_SubstitutionFailure; } // C++ [temp.arg.explicit]p2: // Trailing template arguments that can be deduced (14.8.2) may be // omitted from the list of explicit template-arguments. If all of the // template arguments can be deduced, they may all be omitted; in this // case, the empty template argument list <> itself may also be omitted. // // Take all of the explicitly-specified arguments and put them into the // set of deduced template arguments. Deduced.reserve(TemplateParams->size()); for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) Deduced.push_back(ExplicitArgumentList->get(I)); return TDK_Success; } /// \brief Finish template argument deduction for a function template, /// checking the deduced template arguments for completeness and forming /// the function template specialization. Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, llvm::SmallVectorImpl &Deduced, unsigned NumExplicitlySpecified, FunctionDecl *&Specialization, TemplateDeductionInfo &Info) { TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); // Template argument deduction for function templates in a SFINAE context. // Trap any errors that might occur. SFINAETrap Trap(*this); // Enter a new template instantiation context while we instantiate the // actual function declaration. InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), FunctionTemplate, Deduced.data(), Deduced.size(), ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution, Info); if (Inst) return TDK_InstantiationDepth; ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); // C++ [temp.deduct.type]p2: // [...] or if any template argument remains neither deduced nor // explicitly specified, template argument deduction fails. llvm::SmallVector Builder; for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) { NamedDecl *Param = TemplateParams->getParam(I); if (!Deduced[I].isNull()) { if (I < NumExplicitlySpecified) { // We have already fully type-checked and converted this // argument, because it was explicitly-specified. Just record the // presence of this argument. Builder.push_back(Deduced[I]); continue; } // We have deduced this argument, so it still needs to be // checked and converted. // First, for a non-type template parameter type that is // initialized by a declaration, we need the type of the // corresponding non-type template parameter. QualType NTTPType; if (NonTypeTemplateParmDecl *NTTP = dyn_cast(Param)) { NTTPType = NTTP->getType(); if (NTTPType->isDependentType()) { TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Builder.data(), Builder.size()); NTTPType = SubstType(NTTPType, MultiLevelTemplateArgumentList(TemplateArgs), NTTP->getLocation(), NTTP->getDeclName()); if (NTTPType.isNull()) { Info.Param = makeTemplateParameter(Param); // FIXME: These template arguments are temporary. Free them! Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size())); return TDK_SubstitutionFailure; } } } if (ConvertDeducedTemplateArgument(*this, Param, Deduced[I], FunctionTemplate, NTTPType, Info, true, Builder)) { Info.Param = makeTemplateParameter(Param); // FIXME: These template arguments are temporary. Free them! Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size())); return TDK_SubstitutionFailure; } continue; } // C++0x [temp.arg.explicit]p3: // A trailing template parameter pack (14.5.3) not otherwise deduced will // be deduced to an empty sequence of template arguments. // FIXME: Where did the word "trailing" come from? if (Param->isTemplateParameterPack()) { Builder.push_back(TemplateArgument(0, 0)); continue; } // Substitute into the default template argument, if available. TemplateArgumentLoc DefArg = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, FunctionTemplate->getLocation(), FunctionTemplate->getSourceRange().getEnd(), Param, Builder); // If there was no default argument, deduction is incomplete. if (DefArg.getArgument().isNull()) { Info.Param = makeTemplateParameter( const_cast(TemplateParams->getParam(I))); return TDK_Incomplete; } // Check whether we can actually use the default argument. if (CheckTemplateArgument(Param, DefArg, FunctionTemplate, FunctionTemplate->getLocation(), FunctionTemplate->getSourceRange().getEnd(), Builder, CTAK_Deduced)) { Info.Param = makeTemplateParameter( const_cast(TemplateParams->getParam(I))); // FIXME: These template arguments are temporary. Free them! Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size())); return TDK_SubstitutionFailure; } // If we get here, we successfully used the default template argument. } // Form the template argument list from the deduced template arguments. TemplateArgumentList *DeducedArgumentList = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); Info.reset(DeducedArgumentList); // Substitute the deduced template arguments into the function template // declaration to produce the function template specialization. DeclContext *Owner = FunctionTemplate->getDeclContext(); if (FunctionTemplate->getFriendObjectKind()) Owner = FunctionTemplate->getLexicalDeclContext(); Specialization = cast_or_null( SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, MultiLevelTemplateArgumentList(*DeducedArgumentList))); if (!Specialization) return TDK_SubstitutionFailure; assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == FunctionTemplate->getCanonicalDecl()); // If the template argument list is owned by the function template // specialization, release it. if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList && !Trap.hasErrorOccurred()) Info.take(); // There may have been an error that did not prevent us from constructing a // declaration. Mark the declaration invalid and return with a substitution // failure. if (Trap.hasErrorOccurred()) { Specialization->setInvalidDecl(true); return TDK_SubstitutionFailure; } // If we suppressed any diagnostics while performing template argument // deduction, and if we haven't already instantiated this declaration, // keep track of these diagnostics. They'll be emitted if this specialization // is actually used. if (Info.diag_begin() != Info.diag_end()) { llvm::DenseMap >::iterator Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl()); if (Pos == SuppressedDiagnostics.end()) SuppressedDiagnostics[Specialization->getCanonicalDecl()] .append(Info.diag_begin(), Info.diag_end()); } return TDK_Success; } /// Gets the type of a function for template-argument-deducton /// purposes when it's considered as part of an overload set. static QualType GetTypeOfFunction(ASTContext &Context, const OverloadExpr::FindResult &R, FunctionDecl *Fn) { if (CXXMethodDecl *Method = dyn_cast(Fn)) if (Method->isInstance()) { // An instance method that's referenced in a form that doesn't // look like a member pointer is just invalid. if (!R.HasFormOfMemberPointer) return QualType(); return Context.getMemberPointerType(Fn->getType(), Context.getTypeDeclType(Method->getParent()).getTypePtr()); } if (!R.IsAddressOfOperand) return Fn->getType(); return Context.getPointerType(Fn->getType()); } /// Apply the deduction rules for overload sets. /// /// \return the null type if this argument should be treated as an /// undeduced context static QualType ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, Expr *Arg, QualType ParamType, bool ParamWasReference) { OverloadExpr::FindResult R = OverloadExpr::find(Arg); OverloadExpr *Ovl = R.Expression; // C++0x [temp.deduct.call]p4 unsigned TDF = 0; if (ParamWasReference) TDF |= TDF_ParamWithReferenceType; if (R.IsAddressOfOperand) TDF |= TDF_IgnoreQualifiers; // If there were explicit template arguments, we can only find // something via C++ [temp.arg.explicit]p3, i.e. if the arguments // unambiguously name a full specialization. if (Ovl->hasExplicitTemplateArgs()) { // But we can still look for an explicit specialization. if (FunctionDecl *ExplicitSpec = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) return GetTypeOfFunction(S.Context, R, ExplicitSpec); return QualType(); } // C++0x [temp.deduct.call]p6: // When P is a function type, pointer to function type, or pointer // to member function type: if (!ParamType->isFunctionType() && !ParamType->isFunctionPointerType() && !ParamType->isMemberFunctionPointerType()) return QualType(); QualType Match; for (UnresolvedSetIterator I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) { NamedDecl *D = (*I)->getUnderlyingDecl(); // - If the argument is an overload set containing one or more // function templates, the parameter is treated as a // non-deduced context. if (isa(D)) return QualType(); FunctionDecl *Fn = cast(D); QualType ArgType = GetTypeOfFunction(S.Context, R, Fn); if (ArgType.isNull()) continue; // Function-to-pointer conversion. if (!ParamWasReference && ParamType->isPointerType() && ArgType->isFunctionType()) ArgType = S.Context.getPointerType(ArgType); // - If the argument is an overload set (not containing function // templates), trial argument deduction is attempted using each // of the members of the set. If deduction succeeds for only one // of the overload set members, that member is used as the // argument value for the deduction. If deduction succeeds for // more than one member of the overload set the parameter is // treated as a non-deduced context. // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: // Type deduction is done independently for each P/A pair, and // the deduced template argument values are then combined. // So we do not reject deductions which were made elsewhere. llvm::SmallVector Deduced(TemplateParams->size()); TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); Sema::TemplateDeductionResult Result = DeduceTemplateArguments(S, TemplateParams, ParamType, ArgType, Info, Deduced, TDF); if (Result) continue; if (!Match.isNull()) return QualType(); Match = ArgType; } return Match; } /// \brief Perform template argument deduction from a function call /// (C++ [temp.deduct.call]). /// /// \param FunctionTemplate the function template for which we are performing /// template argument deduction. /// /// \param ExplicitTemplateArguments the explicit template arguments provided /// for this call. /// /// \param Args the function call arguments /// /// \param NumArgs the number of arguments in Args /// /// \param Name the name of the function being called. This is only significant /// when the function template is a conversion function template, in which /// case this routine will also perform template argument deduction based on /// the function to which /// /// \param Specialization if template argument deduction was successful, /// this will be set to the function template specialization produced by /// template argument deduction. /// /// \param Info the argument will be updated to provide additional information /// about template argument deduction. /// /// \returns the result of template argument deduction. Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, const TemplateArgumentListInfo *ExplicitTemplateArgs, Expr **Args, unsigned NumArgs, FunctionDecl *&Specialization, TemplateDeductionInfo &Info) { FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); // C++ [temp.deduct.call]p1: // Template argument deduction is done by comparing each function template // parameter type (call it P) with the type of the corresponding argument // of the call (call it A) as described below. unsigned CheckArgs = NumArgs; if (NumArgs < Function->getMinRequiredArguments()) return TDK_TooFewArguments; else if (NumArgs > Function->getNumParams()) { const FunctionProtoType *Proto = Function->getType()->getAs(); if (!Proto->isVariadic()) return TDK_TooManyArguments; CheckArgs = Function->getNumParams(); } // The types of the parameters from which we will perform template argument // deduction. LocalInstantiationScope InstScope(*this); TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); llvm::SmallVector Deduced; llvm::SmallVector ParamTypes; unsigned NumExplicitlySpecified = 0; if (ExplicitTemplateArgs) { TemplateDeductionResult Result = SubstituteExplicitTemplateArguments(FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes, 0, Info); if (Result) return Result; NumExplicitlySpecified = Deduced.size(); } else { // Just fill in the parameter types from the function declaration. for (unsigned I = 0; I != CheckArgs; ++I) ParamTypes.push_back(Function->getParamDecl(I)->getType()); } // Deduce template arguments from the function parameters. Deduced.resize(TemplateParams->size()); for (unsigned I = 0; I != CheckArgs; ++I) { QualType ParamType = ParamTypes[I]; QualType ArgType = Args[I]->getType(); // C++0x [temp.deduct.call]p3: // If P is a cv-qualified type, the top level cv-qualifiers of P’s type // are ignored for type deduction. if (ParamType.getCVRQualifiers()) ParamType = ParamType.getLocalUnqualifiedType(); const ReferenceType *ParamRefType = ParamType->getAs(); if (ParamRefType) { // [...] If P is a reference type, the type referred to by P is used // for type deduction. ParamType = ParamRefType->getPointeeType(); } // Overload sets usually make this parameter an undeduced // context, but there are sometimes special circumstances. if (ArgType == Context.OverloadTy) { ArgType = ResolveOverloadForDeduction(*this, TemplateParams, Args[I], ParamType, ParamRefType != 0); if (ArgType.isNull()) continue; } if (ParamRefType) { // C++0x [temp.deduct.call]p3: // [...] If P is of the form T&&, where T is a template parameter, and // the argument is an lvalue, the type A& is used in place of A for // type deduction. if (ParamRefType->isRValueReferenceType() && ParamRefType->getAs() && Args[I]->isLValue()) ArgType = Context.getLValueReferenceType(ArgType); } else { // C++ [temp.deduct.call]p2: // If P is not a reference type: // - If A is an array type, the pointer type produced by the // array-to-pointer standard conversion (4.2) is used in place of // A for type deduction; otherwise, if (ArgType->isArrayType()) ArgType = Context.getArrayDecayedType(ArgType); // - If A is a function type, the pointer type produced by the // function-to-pointer standard conversion (4.3) is used in place // of A for type deduction; otherwise, else if (ArgType->isFunctionType()) ArgType = Context.getPointerType(ArgType); else { // - If A is a cv-qualified type, the top level cv-qualifiers of A’s // type are ignored for type deduction. QualType CanonArgType = Context.getCanonicalType(ArgType); if (ArgType.getCVRQualifiers()) ArgType = ArgType.getUnqualifiedType(); } } // C++0x [temp.deduct.call]p4: // In general, the deduction process attempts to find template argument // values that will make the deduced A identical to A (after the type A // is transformed as described above). [...] unsigned TDF = TDF_SkipNonDependent; // - If the original P is a reference type, the deduced A (i.e., the // type referred to by the reference) can be more cv-qualified than // the transformed A. if (ParamRefType) TDF |= TDF_ParamWithReferenceType; // - The transformed A can be another pointer or pointer to member // type that can be converted to the deduced A via a qualification // conversion (4.4). if (ArgType->isPointerType() || ArgType->isMemberPointerType() || ArgType->isObjCObjectPointerType()) TDF |= TDF_IgnoreQualifiers; // - If P is a class and P has the form simple-template-id, then the // transformed A can be a derived class of the deduced A. Likewise, // if P is a pointer to a class of the form simple-template-id, the // transformed A can be a pointer to a derived class pointed to by // the deduced A. if (isSimpleTemplateIdType(ParamType) || (isa(ParamType) && isSimpleTemplateIdType( ParamType->getAs()->getPointeeType()))) TDF |= TDF_DerivedClass; if (TemplateDeductionResult Result = ::DeduceTemplateArguments(*this, TemplateParams, ParamType, ArgType, Info, Deduced, TDF)) return Result; // FIXME: we need to check that the deduced A is the same as A, // modulo the various allowed differences. } return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info); } /// \brief Deduce template arguments when taking the address of a function /// template (C++ [temp.deduct.funcaddr]) or matching a specialization to /// a template. /// /// \param FunctionTemplate the function template for which we are performing /// template argument deduction. /// /// \param ExplicitTemplateArguments the explicitly-specified template /// arguments. /// /// \param ArgFunctionType the function type that will be used as the /// "argument" type (A) when performing template argument deduction from the /// function template's function type. This type may be NULL, if there is no /// argument type to compare against, in C++0x [temp.arg.explicit]p3. /// /// \param Specialization if template argument deduction was successful, /// this will be set to the function template specialization produced by /// template argument deduction. /// /// \param Info the argument will be updated to provide additional information /// about template argument deduction. /// /// \returns the result of template argument deduction. Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, const TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType, FunctionDecl *&Specialization, TemplateDeductionInfo &Info) { FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); QualType FunctionType = Function->getType(); // Substitute any explicit template arguments. LocalInstantiationScope InstScope(*this); llvm::SmallVector Deduced; unsigned NumExplicitlySpecified = 0; llvm::SmallVector ParamTypes; if (ExplicitTemplateArgs) { if (TemplateDeductionResult Result = SubstituteExplicitTemplateArguments(FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes, &FunctionType, Info)) return Result; NumExplicitlySpecified = Deduced.size(); } // Template argument deduction for function templates in a SFINAE context. // Trap any errors that might occur. SFINAETrap Trap(*this); Deduced.resize(TemplateParams->size()); if (!ArgFunctionType.isNull()) { // Deduce template arguments from the function type. if (TemplateDeductionResult Result = ::DeduceTemplateArguments(*this, TemplateParams, FunctionType, ArgFunctionType, Info, Deduced, 0)) return Result; } if (TemplateDeductionResult Result = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info)) return Result; // If the requested function type does not match the actual type of the // specialization, template argument deduction fails. if (!ArgFunctionType.isNull() && !Context.hasSameType(ArgFunctionType, Specialization->getType())) return TDK_NonDeducedMismatch; return TDK_Success; } /// \brief Deduce template arguments for a templated conversion /// function (C++ [temp.deduct.conv]) and, if successful, produce a /// conversion function template specialization. Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, QualType ToType, CXXConversionDecl *&Specialization, TemplateDeductionInfo &Info) { CXXConversionDecl *Conv = cast(FunctionTemplate->getTemplatedDecl()); QualType FromType = Conv->getConversionType(); // Canonicalize the types for deduction. QualType P = Context.getCanonicalType(FromType); QualType A = Context.getCanonicalType(ToType); // C++0x [temp.deduct.conv]p3: // If P is a reference type, the type referred to by P is used for // type deduction. if (const ReferenceType *PRef = P->getAs()) P = PRef->getPointeeType(); // C++0x [temp.deduct.conv]p3: // If A is a reference type, the type referred to by A is used // for type deduction. if (const ReferenceType *ARef = A->getAs()) A = ARef->getPointeeType(); // C++ [temp.deduct.conv]p2: // // If A is not a reference type: else { assert(!A->isReferenceType() && "Reference types were handled above"); // - If P is an array type, the pointer type produced by the // array-to-pointer standard conversion (4.2) is used in place // of P for type deduction; otherwise, if (P->isArrayType()) P = Context.getArrayDecayedType(P); // - If P is a function type, the pointer type produced by the // function-to-pointer standard conversion (4.3) is used in // place of P for type deduction; otherwise, else if (P->isFunctionType()) P = Context.getPointerType(P); // - If P is a cv-qualified type, the top level cv-qualifiers of // P’s type are ignored for type deduction. else P = P.getUnqualifiedType(); // C++0x [temp.deduct.conv]p3: // If A is a cv-qualified type, the top level cv-qualifiers of A’s // type are ignored for type deduction. A = A.getUnqualifiedType(); } // Template argument deduction for function templates in a SFINAE context. // Trap any errors that might occur. SFINAETrap Trap(*this); // C++ [temp.deduct.conv]p1: // Template argument deduction is done by comparing the return // type of the template conversion function (call it P) with the // type that is required as the result of the conversion (call it // A) as described in 14.8.2.4. TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); llvm::SmallVector Deduced; Deduced.resize(TemplateParams->size()); // C++0x [temp.deduct.conv]p4: // In general, the deduction process attempts to find template // argument values that will make the deduced A identical to // A. However, there are two cases that allow a difference: unsigned TDF = 0; // - If the original A is a reference type, A can be more // cv-qualified than the deduced A (i.e., the type referred to // by the reference) if (ToType->isReferenceType()) TDF |= TDF_ParamWithReferenceType; // - The deduced A can be another pointer or pointer to member // type that can be converted to A via a qualification // conversion. // // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when // both P and A are pointers or member pointers. In this case, we // just ignore cv-qualifiers completely). if ((P->isPointerType() && A->isPointerType()) || (P->isMemberPointerType() && P->isMemberPointerType())) TDF |= TDF_IgnoreQualifiers; if (TemplateDeductionResult Result = ::DeduceTemplateArguments(*this, TemplateParams, P, A, Info, Deduced, TDF)) return Result; // FIXME: we need to check that the deduced A is the same as A, // modulo the various allowed differences. // Finish template argument deduction. LocalInstantiationScope InstScope(*this); FunctionDecl *Spec = 0; TemplateDeductionResult Result = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, Info); Specialization = cast_or_null(Spec); return Result; } /// \brief Deduce template arguments for a function template when there is /// nothing to deduce against (C++0x [temp.arg.explicit]p3). /// /// \param FunctionTemplate the function template for which we are performing /// template argument deduction. /// /// \param ExplicitTemplateArguments the explicitly-specified template /// arguments. /// /// \param Specialization if template argument deduction was successful, /// this will be set to the function template specialization produced by /// template argument deduction. /// /// \param Info the argument will be updated to provide additional information /// about template argument deduction. /// /// \returns the result of template argument deduction. Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, const TemplateArgumentListInfo *ExplicitTemplateArgs, FunctionDecl *&Specialization, TemplateDeductionInfo &Info) { return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, QualType(), Specialization, Info); } /// \brief Stores the result of comparing the qualifiers of two types. enum DeductionQualifierComparison { NeitherMoreQualified = 0, ParamMoreQualified, ArgMoreQualified }; /// \brief Deduce the template arguments during partial ordering by comparing /// the parameter type and the argument type (C++0x [temp.deduct.partial]). /// /// \param S the semantic analysis object within which we are deducing /// /// \param TemplateParams the template parameters that we are deducing /// /// \param ParamIn the parameter type /// /// \param ArgIn the argument type /// /// \param Info information about the template argument deduction itself /// /// \param Deduced the deduced template arguments /// /// \returns the result of template argument deduction so far. Note that a /// "success" result means that template argument deduction has not yet failed, /// but it may still fail, later, for other reasons. static Sema::TemplateDeductionResult DeduceTemplateArgumentsDuringPartialOrdering(Sema &S, TemplateParameterList *TemplateParams, QualType ParamIn, QualType ArgIn, TemplateDeductionInfo &Info, llvm::SmallVectorImpl &Deduced, llvm::SmallVectorImpl *QualifierComparisons) { CanQualType Param = S.Context.getCanonicalType(ParamIn); CanQualType Arg = S.Context.getCanonicalType(ArgIn); // C++0x [temp.deduct.partial]p5: // Before the partial ordering is done, certain transformations are // performed on the types used for partial ordering: // - If P is a reference type, P is replaced by the type referred to. CanQual ParamRef = Param->getAs(); if (!ParamRef.isNull()) Param = ParamRef->getPointeeType(); // - If A is a reference type, A is replaced by the type referred to. CanQual ArgRef = Arg->getAs(); if (!ArgRef.isNull()) Arg = ArgRef->getPointeeType(); if (QualifierComparisons && !ParamRef.isNull() && !ArgRef.isNull()) { // C++0x [temp.deduct.partial]p6: // If both P and A were reference types (before being replaced with the // type referred to above), determine which of the two types (if any) is // more cv-qualified than the other; otherwise the types are considered to // be equally cv-qualified for partial ordering purposes. The result of this // determination will be used below. // // We save this information for later, using it only when deduction // succeeds in both directions. DeductionQualifierComparison QualifierResult = NeitherMoreQualified; if (Param.isMoreQualifiedThan(Arg)) QualifierResult = ParamMoreQualified; else if (Arg.isMoreQualifiedThan(Param)) QualifierResult = ArgMoreQualified; QualifierComparisons->push_back(QualifierResult); } // C++0x [temp.deduct.partial]p7: // Remove any top-level cv-qualifiers: // - If P is a cv-qualified type, P is replaced by the cv-unqualified // version of P. Param = Param.getUnqualifiedType(); // - If A is a cv-qualified type, A is replaced by the cv-unqualified // version of A. Arg = Arg.getUnqualifiedType(); // C++0x [temp.deduct.partial]p8: // Using the resulting types P and A the deduction is then done as // described in 14.9.2.5. If deduction succeeds for a given type, the type // from the argument template is considered to be at least as specialized // as the type from the parameter template. return DeduceTemplateArguments(S, TemplateParams, Param, Arg, Info, Deduced, TDF_None); } static void MarkUsedTemplateParameters(Sema &SemaRef, QualType T, bool OnlyDeduced, unsigned Level, llvm::SmallVectorImpl &Deduced); /// \brief If this is a non-static member function, static void MaybeAddImplicitObjectParameterType(ASTContext &Context, CXXMethodDecl *Method, llvm::SmallVectorImpl &ArgTypes) { if (Method->isStatic()) return; // C++ [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 // // FIXME: We don't have ref-qualifiers yet, so we don't do that part. QualType ArgTy = Context.getTypeDeclType(Method->getParent()); ArgTy = Context.getQualifiedType(ArgTy, Qualifiers::fromCVRMask(Method->getTypeQualifiers())); ArgTy = Context.getLValueReferenceType(ArgTy); ArgTypes.push_back(ArgTy); } /// \brief Determine whether the function template \p FT1 is at least as /// specialized as \p FT2. static bool isAtLeastAsSpecializedAs(Sema &S, SourceLocation Loc, FunctionTemplateDecl *FT1, FunctionTemplateDecl *FT2, TemplatePartialOrderingContext TPOC, llvm::SmallVectorImpl *QualifierComparisons) { FunctionDecl *FD1 = FT1->getTemplatedDecl(); FunctionDecl *FD2 = FT2->getTemplatedDecl(); const FunctionProtoType *Proto1 = FD1->getType()->getAs(); const FunctionProtoType *Proto2 = FD2->getType()->getAs(); assert(Proto1 && Proto2 && "Function templates must have prototypes"); TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); llvm::SmallVector Deduced; Deduced.resize(TemplateParams->size()); // C++0x [temp.deduct.partial]p3: // The types used to determine the ordering depend on the context in which // the partial ordering is done: TemplateDeductionInfo Info(S.Context, Loc); CXXMethodDecl *Method1 = 0; CXXMethodDecl *Method2 = 0; bool IsNonStatic2 = false; bool IsNonStatic1 = false; unsigned Skip2 = 0; switch (TPOC) { case TPOC_Call: { // - In the context of a function call, the function parameter types are // used. Method1 = dyn_cast(FD1); Method2 = dyn_cast(FD2); IsNonStatic1 = Method1 && !Method1->isStatic(); IsNonStatic2 = Method2 && !Method2->isStatic(); // C++0x [temp.func.order]p3: // [...] If only one of the function templates is a non-static // member, that function template is considered to have a new // first parameter inserted in its function parameter list. The // new parameter is of type "reference to cv A," where cv are // the cv-qualifiers of the function template (if any) and A is // the class of which the function template is a member. // // C++98/03 doesn't have this provision, so instead we drop the // first argument of the free function or static member, which // seems to match existing practice. llvm::SmallVector Args1; unsigned Skip1 = !S.getLangOptions().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1; if (S.getLangOptions().CPlusPlus0x && IsNonStatic1 && !IsNonStatic2) MaybeAddImplicitObjectParameterType(S.Context, Method1, Args1); Args1.insert(Args1.end(), Proto1->arg_type_begin() + Skip1, Proto1->arg_type_end()); llvm::SmallVector Args2; Skip2 = !S.getLangOptions().CPlusPlus0x && IsNonStatic1 && !IsNonStatic2; if (S.getLangOptions().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) MaybeAddImplicitObjectParameterType(S.Context, Method2, Args2); Args2.insert(Args2.end(), Proto2->arg_type_begin() + Skip2, Proto2->arg_type_end()); unsigned NumParams = std::min(Args1.size(), Args2.size()); for (unsigned I = 0; I != NumParams; ++I) if (DeduceTemplateArgumentsDuringPartialOrdering(S, TemplateParams, Args2[I], Args1[I], Info, Deduced, QualifierComparisons)) return false; break; } case TPOC_Conversion: // - In the context of a call to a conversion operator, the return types // of the conversion function templates are used. if (DeduceTemplateArgumentsDuringPartialOrdering(S, TemplateParams, Proto2->getResultType(), Proto1->getResultType(), Info, Deduced, QualifierComparisons)) return false; break; case TPOC_Other: // - In other contexts (14.6.6.2) the function template’s function type // is used. if (DeduceTemplateArgumentsDuringPartialOrdering(S, TemplateParams, FD2->getType(), FD1->getType(), Info, Deduced, QualifierComparisons)) return false; break; } // C++0x [temp.deduct.partial]p11: // In most cases, all template parameters must have values in order for // deduction to succeed, but for partial ordering purposes a template // parameter may remain without a value provided it is not used in the // types being used for partial ordering. [ Note: a template parameter used // in a non-deduced context is considered used. -end note] unsigned ArgIdx = 0, NumArgs = Deduced.size(); for (; ArgIdx != NumArgs; ++ArgIdx) if (Deduced[ArgIdx].isNull()) break; if (ArgIdx == NumArgs) { // All template arguments were deduced. FT1 is at least as specialized // as FT2. return true; } // Figure out which template parameters were used. llvm::SmallVector UsedParameters; UsedParameters.resize(TemplateParams->size()); switch (TPOC) { case TPOC_Call: { unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); if (S.getLangOptions().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) ::MarkUsedTemplateParameters(S, Method2->getThisType(S.Context), false, TemplateParams->getDepth(), UsedParameters); for (unsigned I = Skip2; I < NumParams; ++I) ::MarkUsedTemplateParameters(S, Proto2->getArgType(I), false, TemplateParams->getDepth(), UsedParameters); break; } case TPOC_Conversion: ::MarkUsedTemplateParameters(S, Proto2->getResultType(), false, TemplateParams->getDepth(), UsedParameters); break; case TPOC_Other: ::MarkUsedTemplateParameters(S, FD2->getType(), false, TemplateParams->getDepth(), UsedParameters); break; } for (; ArgIdx != NumArgs; ++ArgIdx) // If this argument had no value deduced but was used in one of the types // used for partial ordering, then deduction fails. if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) return false; return true; } /// \brief Returns the more specialized function template according /// to the rules of function template partial ordering (C++ [temp.func.order]). /// /// \param FT1 the first function template /// /// \param FT2 the second function template /// /// \param TPOC the context in which we are performing partial ordering of /// function templates. /// /// \returns the more specialized function template. If neither /// template is more specialized, returns NULL. FunctionTemplateDecl * Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, FunctionTemplateDecl *FT2, SourceLocation Loc, TemplatePartialOrderingContext TPOC) { llvm::SmallVector QualifierComparisons; bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 0); bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, &QualifierComparisons); if (Better1 != Better2) // We have a clear winner return Better1? FT1 : FT2; if (!Better1 && !Better2) // Neither is better than the other return 0; // C++0x [temp.deduct.partial]p10: // If for each type being considered a given template is at least as // specialized for all types and more specialized for some set of types and // the other template is not more specialized for any types or is not at // least as specialized for any types, then the given template is more // specialized than the other template. Otherwise, neither template is more // specialized than the other. Better1 = false; Better2 = false; for (unsigned I = 0, N = QualifierComparisons.size(); I != N; ++I) { // C++0x [temp.deduct.partial]p9: // If, for a given type, deduction succeeds in both directions (i.e., the // types are identical after the transformations above) and if the type // from the argument template is more cv-qualified than the type from the // parameter template (as described above) that type is considered to be // more specialized than the other. If neither type is more cv-qualified // than the other then neither type is more specialized than the other. switch (QualifierComparisons[I]) { case NeitherMoreQualified: break; case ParamMoreQualified: Better1 = true; if (Better2) return 0; break; case ArgMoreQualified: Better2 = true; if (Better1) return 0; break; } } assert(!(Better1 && Better2) && "Should have broken out in the loop above"); if (Better1) return FT1; else if (Better2) return FT2; else return 0; } /// \brief Determine if the two templates are equivalent. static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { if (T1 == T2) return true; if (!T1 || !T2) return false; return T1->getCanonicalDecl() == T2->getCanonicalDecl(); } /// \brief Retrieve the most specialized of the given function template /// specializations. /// /// \param SpecBegin the start iterator of the function template /// specializations that we will be comparing. /// /// \param SpecEnd the end iterator of the function template /// specializations, paired with \p SpecBegin. /// /// \param TPOC the partial ordering context to use to compare the function /// template specializations. /// /// \param Loc the location where the ambiguity or no-specializations /// diagnostic should occur. /// /// \param NoneDiag partial diagnostic used to diagnose cases where there are /// no matching candidates. /// /// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one /// occurs. /// /// \param CandidateDiag partial diagnostic used for each function template /// specialization that is a candidate in the ambiguous ordering. One parameter /// in this diagnostic should be unbound, which will correspond to the string /// describing the template arguments for the function template specialization. /// /// \param Index if non-NULL and the result of this function is non-nULL, /// receives the index corresponding to the resulting function template /// specialization. /// /// \returns the most specialized function template specialization, if /// found. Otherwise, returns SpecEnd. /// /// \todo FIXME: Consider passing in the "also-ran" candidates that failed /// template argument deduction. UnresolvedSetIterator Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd, TemplatePartialOrderingContext TPOC, SourceLocation Loc, const PartialDiagnostic &NoneDiag, const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag) { if (SpecBegin == SpecEnd) { Diag(Loc, NoneDiag); return SpecEnd; } if (SpecBegin + 1 == SpecEnd) return SpecBegin; // Find the function template that is better than all of the templates it // has been compared to. UnresolvedSetIterator Best = SpecBegin; FunctionTemplateDecl *BestTemplate = cast(*Best)->getPrimaryTemplate(); assert(BestTemplate && "Not a function template specialization?"); for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { FunctionTemplateDecl *Challenger = cast(*I)->getPrimaryTemplate(); assert(Challenger && "Not a function template specialization?"); if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, Loc, TPOC), Challenger)) { Best = I; BestTemplate = Challenger; } } // Make sure that the "best" function template is more specialized than all // of the others. bool Ambiguous = false; for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { FunctionTemplateDecl *Challenger = cast(*I)->getPrimaryTemplate(); if (I != Best && !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, Loc, TPOC), BestTemplate)) { Ambiguous = true; break; } } if (!Ambiguous) { // We found an answer. Return it. return Best; } // Diagnose the ambiguity. Diag(Loc, AmbigDiag); // FIXME: Can we order the candidates in some sane way? for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) Diag((*I)->getLocation(), CandidateDiag) << getTemplateArgumentBindingsText( cast(*I)->getPrimaryTemplate()->getTemplateParameters(), *cast(*I)->getTemplateSpecializationArgs()); return SpecEnd; } /// \brief Returns the more specialized class template partial specialization /// according to the rules of partial ordering of class template partial /// specializations (C++ [temp.class.order]). /// /// \param PS1 the first class template partial specialization /// /// \param PS2 the second class template partial specialization /// /// \returns the more specialized class template partial specialization. If /// neither partial specialization is more specialized, returns NULL. ClassTemplatePartialSpecializationDecl * Sema::getMoreSpecializedPartialSpecialization( ClassTemplatePartialSpecializationDecl *PS1, ClassTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) { // C++ [temp.class.order]p1: // For two class template partial specializations, the first is at least as // specialized as the second if, given the following rewrite to two // function templates, the first function template is at least as // specialized as the second according to the ordering rules for function // templates (14.6.6.2): // - the first function template has the same template parameters as the // first partial specialization and has a single function parameter // whose type is a class template specialization with the template // arguments of the first partial specialization, and // - the second function template has the same template parameters as the // second partial specialization and has a single function parameter // whose type is a class template specialization with the template // arguments of the second partial specialization. // // Rather than synthesize function templates, we merely perform the // equivalent partial ordering by performing deduction directly on // the template arguments of the class template partial // specializations. This computation is slightly simpler than the // general problem of function template partial ordering, because // class template partial specializations are more constrained. We // know that every template parameter is deducible from the class // template partial specialization's template arguments, for // example. llvm::SmallVector Deduced; TemplateDeductionInfo Info(Context, Loc); QualType PT1 = PS1->getInjectedSpecializationType(); QualType PT2 = PS2->getInjectedSpecializationType(); // Determine whether PS1 is at least as specialized as PS2 Deduced.resize(PS2->getTemplateParameters()->size()); bool Better1 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, PS2->getTemplateParameters(), PT2, PT1, Info, Deduced, 0); if (Better1) { InstantiatingTemplate Inst(*this, PS2->getLocation(), PS2, Deduced.data(), Deduced.size(), Info); Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, PS1->getTemplateArgs(), Deduced, Info); } // Determine whether PS2 is at least as specialized as PS1 Deduced.clear(); Deduced.resize(PS1->getTemplateParameters()->size()); bool Better2 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, PS1->getTemplateParameters(), PT1, PT2, Info, Deduced, 0); if (Better2) { InstantiatingTemplate Inst(*this, PS1->getLocation(), PS1, Deduced.data(), Deduced.size(), Info); Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, PS2->getTemplateArgs(), Deduced, Info); } if (Better1 == Better2) return 0; return Better1? PS1 : PS2; } static void MarkUsedTemplateParameters(Sema &SemaRef, const TemplateArgument &TemplateArg, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used); /// \brief Mark the template parameters that are used by the given /// expression. static void MarkUsedTemplateParameters(Sema &SemaRef, const Expr *E, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { // We can deduce from a pack expansion. if (const PackExpansionExpr *Expansion = dyn_cast(E)) E = Expansion->getPattern(); // Skip through any implicit casts we added while type-checking. while (const ImplicitCastExpr *ICE = dyn_cast(E)) E = ICE->getSubExpr(); // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to // find other occurrences of template parameters. const DeclRefExpr *DRE = dyn_cast(E); if (!DRE) return; const NonTypeTemplateParmDecl *NTTP = dyn_cast(DRE->getDecl()); if (!NTTP) return; if (NTTP->getDepth() == Depth) Used[NTTP->getIndex()] = true; } /// \brief Mark the template parameters that are used by the given /// nested name specifier. static void MarkUsedTemplateParameters(Sema &SemaRef, NestedNameSpecifier *NNS, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { if (!NNS) return; MarkUsedTemplateParameters(SemaRef, NNS->getPrefix(), OnlyDeduced, Depth, Used); MarkUsedTemplateParameters(SemaRef, QualType(NNS->getAsType(), 0), OnlyDeduced, Depth, Used); } /// \brief Mark the template parameters that are used by the given /// template name. static void MarkUsedTemplateParameters(Sema &SemaRef, TemplateName Name, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { if (TemplateDecl *Template = Name.getAsTemplateDecl()) { if (TemplateTemplateParmDecl *TTP = dyn_cast(Template)) { if (TTP->getDepth() == Depth) Used[TTP->getIndex()] = true; } return; } if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) MarkUsedTemplateParameters(SemaRef, QTN->getQualifier(), OnlyDeduced, Depth, Used); if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) MarkUsedTemplateParameters(SemaRef, DTN->getQualifier(), OnlyDeduced, Depth, Used); } /// \brief Mark the template parameters that are used by the given /// type. static void MarkUsedTemplateParameters(Sema &SemaRef, QualType T, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { if (T.isNull()) return; // Non-dependent types have nothing deducible if (!T->isDependentType()) return; T = SemaRef.Context.getCanonicalType(T); switch (T->getTypeClass()) { case Type::Pointer: MarkUsedTemplateParameters(SemaRef, cast(T)->getPointeeType(), OnlyDeduced, Depth, Used); break; case Type::BlockPointer: MarkUsedTemplateParameters(SemaRef, cast(T)->getPointeeType(), OnlyDeduced, Depth, Used); break; case Type::LValueReference: case Type::RValueReference: MarkUsedTemplateParameters(SemaRef, cast(T)->getPointeeType(), OnlyDeduced, Depth, Used); break; case Type::MemberPointer: { const MemberPointerType *MemPtr = cast(T.getTypePtr()); MarkUsedTemplateParameters(SemaRef, MemPtr->getPointeeType(), OnlyDeduced, Depth, Used); MarkUsedTemplateParameters(SemaRef, QualType(MemPtr->getClass(), 0), OnlyDeduced, Depth, Used); break; } case Type::DependentSizedArray: MarkUsedTemplateParameters(SemaRef, cast(T)->getSizeExpr(), OnlyDeduced, Depth, Used); // Fall through to check the element type case Type::ConstantArray: case Type::IncompleteArray: MarkUsedTemplateParameters(SemaRef, cast(T)->getElementType(), OnlyDeduced, Depth, Used); break; case Type::Vector: case Type::ExtVector: MarkUsedTemplateParameters(SemaRef, cast(T)->getElementType(), OnlyDeduced, Depth, Used); break; case Type::DependentSizedExtVector: { const DependentSizedExtVectorType *VecType = cast(T); MarkUsedTemplateParameters(SemaRef, VecType->getElementType(), OnlyDeduced, Depth, Used); MarkUsedTemplateParameters(SemaRef, VecType->getSizeExpr(), OnlyDeduced, Depth, Used); break; } case Type::FunctionProto: { const FunctionProtoType *Proto = cast(T); MarkUsedTemplateParameters(SemaRef, Proto->getResultType(), OnlyDeduced, Depth, Used); for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) MarkUsedTemplateParameters(SemaRef, Proto->getArgType(I), OnlyDeduced, Depth, Used); break; } case Type::TemplateTypeParm: { const TemplateTypeParmType *TTP = cast(T); if (TTP->getDepth() == Depth) Used[TTP->getIndex()] = true; break; } case Type::InjectedClassName: T = cast(T)->getInjectedSpecializationType(); // fall through case Type::TemplateSpecialization: { const TemplateSpecializationType *Spec = cast(T); MarkUsedTemplateParameters(SemaRef, Spec->getTemplateName(), OnlyDeduced, Depth, Used); // C++0x [temp.deduct.type]p9: // If the template argument list of P contains a pack expansion that is not // the last template argument, the entire template argument list is a // non-deduced context. if (OnlyDeduced && hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) break; for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, Used); break; } case Type::Complex: if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, cast(T)->getElementType(), OnlyDeduced, Depth, Used); break; case Type::DependentName: if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, cast(T)->getQualifier(), OnlyDeduced, Depth, Used); break; case Type::DependentTemplateSpecialization: { const DependentTemplateSpecializationType *Spec = cast(T); if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, Spec->getQualifier(), OnlyDeduced, Depth, Used); // C++0x [temp.deduct.type]p9: // If the template argument list of P contains a pack expansion that is not // the last template argument, the entire template argument list is a // non-deduced context. if (OnlyDeduced && hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) break; for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, Used); break; } case Type::TypeOf: if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, cast(T)->getUnderlyingType(), OnlyDeduced, Depth, Used); break; case Type::TypeOfExpr: if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, cast(T)->getUnderlyingExpr(), OnlyDeduced, Depth, Used); break; case Type::Decltype: if (!OnlyDeduced) MarkUsedTemplateParameters(SemaRef, cast(T)->getUnderlyingExpr(), OnlyDeduced, Depth, Used); break; case Type::PackExpansion: MarkUsedTemplateParameters(SemaRef, cast(T)->getPattern(), OnlyDeduced, Depth, Used); break; // None of these types have any template parameters in them. case Type::Builtin: case Type::VariableArray: case Type::FunctionNoProto: case Type::Record: case Type::Enum: case Type::ObjCInterface: case Type::ObjCObject: case Type::ObjCObjectPointer: case Type::UnresolvedUsing: #define TYPE(Class, Base) #define ABSTRACT_TYPE(Class, Base) #define DEPENDENT_TYPE(Class, Base) #define NON_CANONICAL_TYPE(Class, Base) case Type::Class: #include "clang/AST/TypeNodes.def" break; } } /// \brief Mark the template parameters that are used by this /// template argument. static void MarkUsedTemplateParameters(Sema &SemaRef, const TemplateArgument &TemplateArg, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { switch (TemplateArg.getKind()) { case TemplateArgument::Null: case TemplateArgument::Integral: case TemplateArgument::Declaration: break; case TemplateArgument::Type: MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsType(), OnlyDeduced, Depth, Used); break; case TemplateArgument::Template: case TemplateArgument::TemplateExpansion: MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsTemplateOrTemplatePattern(), OnlyDeduced, Depth, Used); break; case TemplateArgument::Expression: MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsExpr(), OnlyDeduced, Depth, Used); break; case TemplateArgument::Pack: for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), PEnd = TemplateArg.pack_end(); P != PEnd; ++P) MarkUsedTemplateParameters(SemaRef, *P, OnlyDeduced, Depth, Used); break; } } /// \brief Mark the template parameters can be deduced by the given /// template argument list. /// /// \param TemplateArgs the template argument list from which template /// parameters will be deduced. /// /// \param Deduced a bit vector whose elements will be set to \c true /// to indicate when the corresponding template parameter will be /// deduced. void Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, bool OnlyDeduced, unsigned Depth, llvm::SmallVectorImpl &Used) { // C++0x [temp.deduct.type]p9: // If the template argument list of P contains a pack expansion that is not // the last template argument, the entire template argument list is a // non-deduced context. if (OnlyDeduced && hasPackExpansionBeforeEnd(TemplateArgs.data(), TemplateArgs.size())) return; for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) ::MarkUsedTemplateParameters(*this, TemplateArgs[I], OnlyDeduced, Depth, Used); } /// \brief Marks all of the template parameters that will be deduced by a /// call to the given function template. void Sema::MarkDeducedTemplateParameters(FunctionTemplateDecl *FunctionTemplate, llvm::SmallVectorImpl &Deduced) { TemplateParameterList *TemplateParams = FunctionTemplate->getTemplateParameters(); Deduced.clear(); Deduced.resize(TemplateParams->size()); FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) ::MarkUsedTemplateParameters(*this, Function->getParamDecl(I)->getType(), true, TemplateParams->getDepth(), Deduced); }