| //===------- 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 "Sema.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/DeclTemplate.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/Parse/DeclSpec.h" |
| #include "llvm/Support/Compiler.h" |
| using namespace clang; |
| |
| static bool |
| DeduceTemplateArguments(ASTContext &Context, const TemplateArgument &Param, |
| const TemplateArgument &Arg, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced); |
| |
| /// \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<ImplicitCastExpr>(E)) |
| E = IC->getSubExpr(); |
| |
| if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) |
| return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); |
| |
| return 0; |
| } |
| |
| /// \brief Deduce the value of the given non-type template parameter |
| /// from the given constant. |
| /// |
| /// \returns true if deduction succeeded, false otherwise. |
| static bool DeduceNonTypeTemplateArgument(ASTContext &Context, |
| NonTypeTemplateParmDecl *NTTP, |
| llvm::APInt Value, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced) { |
| assert(NTTP->getDepth() == 0 && |
| "Cannot deduce non-type template argument with depth > 0"); |
| |
| if (Deduced[NTTP->getIndex()].isNull()) { |
| Deduced[NTTP->getIndex()] = TemplateArgument(SourceLocation(), |
| llvm::APSInt(Value), |
| NTTP->getType()); |
| return true; |
| } |
| |
| if (Deduced[NTTP->getIndex()].getKind() != TemplateArgument::Integral) |
| return false; |
| |
| // If the template argument was previously deduced to a negative value, |
| // then our deduction fails. |
| const llvm::APSInt *PrevValuePtr = Deduced[NTTP->getIndex()].getAsIntegral(); |
| assert(PrevValuePtr && "Not an integral template argument?"); |
| if (PrevValuePtr->isSigned() && PrevValuePtr->isNegative()) |
| return false; |
| |
| llvm::APInt PrevValue = *PrevValuePtr; |
| if (Value.getBitWidth() > PrevValue.getBitWidth()) |
| PrevValue.zext(Value.getBitWidth()); |
| else if (Value.getBitWidth() < PrevValue.getBitWidth()) |
| Value.zext(PrevValue.getBitWidth()); |
| return Value == PrevValue; |
| } |
| |
| /// \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 bool DeduceNonTypeTemplateArgument(ASTContext &Context, |
| NonTypeTemplateParmDecl *NTTP, |
| Expr *Value, |
| llvm::SmallVectorImpl<TemplateArgument> &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."); |
| |
| if (Deduced[NTTP->getIndex()].isNull()) { |
| // FIXME: Clone the Value? |
| Deduced[NTTP->getIndex()] = TemplateArgument(Value); |
| return true; |
| } |
| |
| if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Integral) { |
| // Okay, we deduced a constant in one case and a dependent expression |
| // in another case. FIXME: Later, we will check that instantiating the |
| // dependent expression gives us the constant value. |
| return true; |
| } |
| |
| // FIXME: Compare the expressions for equality! |
| return true; |
| } |
| |
| static bool DeduceTemplateArguments(ASTContext &Context, |
| TemplateName Param, |
| TemplateName Arg, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced) { |
| // FIXME: Implement template argument deduction for template |
| // template parameters. |
| |
| TemplateDecl *ParamDecl = Param.getAsTemplateDecl(); |
| TemplateDecl *ArgDecl = Arg.getAsTemplateDecl(); |
| |
| if (!ParamDecl || !ArgDecl) |
| return false; |
| |
| ParamDecl = cast<TemplateDecl>(Context.getCanonicalDecl(ParamDecl)); |
| ArgDecl = cast<TemplateDecl>(Context.getCanonicalDecl(ArgDecl)); |
| return ParamDecl == ArgDecl; |
| } |
| |
| static bool DeduceTemplateArguments(ASTContext &Context, QualType Param, |
| QualType Arg, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced) { |
| // We only want to look at the canonical types, since typedefs and |
| // sugar are not part of template argument deduction. |
| Param = Context.getCanonicalType(Param); |
| Arg = Context.getCanonicalType(Arg); |
| |
| // If the parameter type is not dependent, just compare the types |
| // directly. |
| if (!Param->isDependentType()) |
| return Param == Arg; |
| |
| // 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->getAsTemplateTypeParmType()) { |
| // The argument type can not be less qualified than the parameter |
| // type. |
| if (Param.isMoreQualifiedThan(Arg)) |
| return false; |
| |
| assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0"); |
| |
| unsigned Quals = Arg.getCVRQualifiers() & ~Param.getCVRQualifiers(); |
| QualType DeducedType = Arg.getQualifiedType(Quals); |
| unsigned Index = TemplateTypeParm->getIndex(); |
| |
| if (Deduced[Index].isNull()) |
| Deduced[Index] = TemplateArgument(SourceLocation(), DeducedType); |
| else { |
| // C++ [temp.deduct.type]p2: |
| // [...] If type deduction cannot be done for any P/A pair, or if for |
| // any pair the deduction leads to more than one possible set of |
| // deduced values, or if different pairs yield different deduced |
| // values, or if any template argument remains neither deduced nor |
| // explicitly specified, template argument deduction fails. |
| if (Deduced[Index].getAsType() != DeducedType) |
| return false; |
| } |
| return true; |
| } |
| |
| if (Param.getCVRQualifiers() != Arg.getCVRQualifiers()) |
| return false; |
| |
| switch (Param->getTypeClass()) { |
| // No deduction possible for these types |
| case Type::Builtin: |
| return false; |
| |
| |
| // T * |
| case Type::Pointer: { |
| const PointerType *PointerArg = Arg->getAsPointerType(); |
| if (!PointerArg) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| cast<PointerType>(Param)->getPointeeType(), |
| PointerArg->getPointeeType(), |
| Deduced); |
| } |
| |
| // T & |
| case Type::LValueReference: { |
| const LValueReferenceType *ReferenceArg = Arg->getAsLValueReferenceType(); |
| if (!ReferenceArg) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| cast<LValueReferenceType>(Param)->getPointeeType(), |
| ReferenceArg->getPointeeType(), |
| Deduced); |
| } |
| |
| // T && [C++0x] |
| case Type::RValueReference: { |
| const RValueReferenceType *ReferenceArg = Arg->getAsRValueReferenceType(); |
| if (!ReferenceArg) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| cast<RValueReferenceType>(Param)->getPointeeType(), |
| ReferenceArg->getPointeeType(), |
| Deduced); |
| } |
| |
| // T [] (implied, but not stated explicitly) |
| case Type::IncompleteArray: { |
| const IncompleteArrayType *IncompleteArrayArg = |
| Context.getAsIncompleteArrayType(Arg); |
| if (!IncompleteArrayArg) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| Context.getAsIncompleteArrayType(Param)->getElementType(), |
| IncompleteArrayArg->getElementType(), |
| Deduced); |
| } |
| |
| // T [integer-constant] |
| case Type::ConstantArray: { |
| const ConstantArrayType *ConstantArrayArg = |
| Context.getAsConstantArrayType(Arg); |
| if (!ConstantArrayArg) |
| return false; |
| |
| const ConstantArrayType *ConstantArrayParm = |
| Context.getAsConstantArrayType(Param); |
| if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| ConstantArrayParm->getElementType(), |
| ConstantArrayArg->getElementType(), |
| Deduced); |
| } |
| |
| // type [i] |
| case Type::DependentSizedArray: { |
| const ArrayType *ArrayArg = dyn_cast<ArrayType>(Arg); |
| if (!ArrayArg) |
| return false; |
| |
| // Check the element type of the arrays |
| const DependentSizedArrayType *DependentArrayParm |
| = cast<DependentSizedArrayType>(Param); |
| if (!DeduceTemplateArguments(Context, |
| DependentArrayParm->getElementType(), |
| ArrayArg->getElementType(), |
| Deduced)) |
| return false; |
| |
| // Determine the array bound is something we can deduce. |
| NonTypeTemplateParmDecl *NTTP |
| = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr()); |
| if (!NTTP) |
| return true; |
| |
| // 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<ConstantArrayType>(ArrayArg)) |
| return DeduceNonTypeTemplateArgument(Context, NTTP, |
| ConstantArrayArg->getSize(), |
| Deduced); |
| if (const DependentSizedArrayType *DependentArrayArg |
| = dyn_cast<DependentSizedArrayType>(ArrayArg)) |
| return DeduceNonTypeTemplateArgument(Context, NTTP, |
| DependentArrayArg->getSizeExpr(), |
| Deduced); |
| |
| // Incomplete type does not match a dependently-sized array type |
| return false; |
| } |
| |
| // type(*)(T) |
| // T(*)() |
| // T(*)(T) |
| case Type::FunctionProto: { |
| const FunctionProtoType *FunctionProtoArg = |
| dyn_cast<FunctionProtoType>(Arg); |
| if (!FunctionProtoArg) |
| return false; |
| |
| const FunctionProtoType *FunctionProtoParam = |
| cast<FunctionProtoType>(Param); |
| |
| if (FunctionProtoParam->getTypeQuals() != |
| FunctionProtoArg->getTypeQuals()) |
| return false; |
| |
| if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs()) |
| return false; |
| |
| if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) |
| return false; |
| |
| // Check return types. |
| if (!DeduceTemplateArguments(Context, |
| FunctionProtoParam->getResultType(), |
| FunctionProtoArg->getResultType(), |
| Deduced)) |
| return false; |
| |
| for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) { |
| // Check argument types. |
| if (!DeduceTemplateArguments(Context, |
| FunctionProtoParam->getArgType(I), |
| FunctionProtoArg->getArgType(I), |
| Deduced)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // template-name<T> (wheretemplate-name refers to a class template) |
| // template-name<i> |
| // TT<T> (TODO) |
| // TT<i> (TODO) |
| // TT<> (TODO) |
| case Type::TemplateSpecialization: { |
| const TemplateSpecializationType *SpecParam |
| = cast<TemplateSpecializationType>(Param); |
| |
| // Check whether the template argument is a dependent template-id. |
| // FIXME: This is untested code; it can be tested when we implement |
| // partial ordering of class template partial specializations. |
| if (const TemplateSpecializationType *SpecArg |
| = dyn_cast<TemplateSpecializationType>(Arg)) { |
| // Perform template argument deduction for the template name. |
| if (!DeduceTemplateArguments(Context, |
| SpecParam->getTemplateName(), |
| SpecArg->getTemplateName(), |
| Deduced)) |
| return false; |
| |
| unsigned NumArgs = SpecParam->getNumArgs(); |
| |
| // FIXME: When one of the template-names refers to a |
| // declaration with default template arguments, do we need to |
| // fill in those default template arguments here? Most likely, |
| // the answer is "yes", but I don't see any references. This |
| // issue may be resolved elsewhere, because we may want to |
| // instantiate default template arguments when |
| if (SpecArg->getNumArgs() != NumArgs) |
| return false; |
| |
| // Perform template argument deduction on each template |
| // argument. |
| for (unsigned I = 0; I != NumArgs; ++I) |
| if (!DeduceTemplateArguments(Context, |
| SpecParam->getArg(I), |
| SpecArg->getArg(I), |
| Deduced)) |
| return false; |
| |
| return true; |
| } |
| |
| // If the argument type is a class template specialization, we |
| // perform template argument deduction using its template |
| // arguments. |
| const RecordType *RecordArg = dyn_cast<RecordType>(Arg); |
| if (!RecordArg) |
| return false; |
| |
| ClassTemplateSpecializationDecl *SpecArg |
| = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl()); |
| if (!SpecArg) |
| return false; |
| |
| // Perform template argument deduction for the template name. |
| if (!DeduceTemplateArguments(Context, |
| SpecParam->getTemplateName(), |
| TemplateName(SpecArg->getSpecializedTemplate()), |
| Deduced)) |
| return false; |
| |
| // FIXME: Can the # of arguments in the parameter and the argument differ? |
| unsigned NumArgs = SpecParam->getNumArgs(); |
| const TemplateArgumentList &ArgArgs = SpecArg->getTemplateArgs(); |
| if (NumArgs != ArgArgs.size()) |
| return false; |
| |
| for (unsigned I = 0; I != NumArgs; ++I) |
| if (!DeduceTemplateArguments(Context, |
| SpecParam->getArg(I), |
| ArgArgs.get(I), |
| Deduced)) |
| return false; |
| |
| return true; |
| } |
| |
| // 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<MemberPointerType>(Param); |
| const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg); |
| if (!MemPtrArg) |
| return false; |
| |
| return DeduceTemplateArguments(Context, |
| MemPtrParam->getPointeeType(), |
| MemPtrArg->getPointeeType(), |
| Deduced) && |
| DeduceTemplateArguments(Context, |
| QualType(MemPtrParam->getClass(), 0), |
| QualType(MemPtrArg->getClass(), 0), |
| Deduced); |
| } |
| |
| case Type::TypeOfExpr: |
| case Type::TypeOf: |
| case Type::Typename: |
| // No template argument deduction for these types |
| return true; |
| |
| default: |
| break; |
| } |
| |
| // FIXME: Many more cases to go (to go). |
| return false; |
| } |
| |
| static bool |
| DeduceTemplateArguments(ASTContext &Context, const TemplateArgument &Param, |
| const TemplateArgument &Arg, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced) { |
| switch (Param.getKind()) { |
| case TemplateArgument::Null: |
| assert(false && "Null template argument in parameter list"); |
| break; |
| |
| case TemplateArgument::Type: |
| assert(Arg.getKind() == TemplateArgument::Type && "Type/value mismatch"); |
| return DeduceTemplateArguments(Context, Param.getAsType(), |
| Arg.getAsType(), Deduced); |
| |
| case TemplateArgument::Declaration: |
| // FIXME: Implement this check |
| assert(false && "Unimplemented template argument deduction case"); |
| return false; |
| |
| case TemplateArgument::Integral: |
| if (Arg.getKind() == TemplateArgument::Integral) { |
| // FIXME: Zero extension + sign checking here? |
| return *Param.getAsIntegral() == *Arg.getAsIntegral(); |
| } |
| if (Arg.getKind() == TemplateArgument::Expression) |
| return false; |
| |
| assert(false && "Type/value mismatch"); |
| return false; |
| |
| case TemplateArgument::Expression: { |
| if (NonTypeTemplateParmDecl *NTTP |
| = getDeducedParameterFromExpr(Param.getAsExpr())) { |
| if (Arg.getKind() == TemplateArgument::Integral) |
| // FIXME: Sign problems here |
| return DeduceNonTypeTemplateArgument(Context, NTTP, |
| *Arg.getAsIntegral(), Deduced); |
| if (Arg.getKind() == TemplateArgument::Expression) |
| return DeduceNonTypeTemplateArgument(Context, NTTP, Arg.getAsExpr(), |
| Deduced); |
| |
| assert(false && "Type/value mismatch"); |
| return false; |
| } |
| |
| // Can't deduce anything, but that's okay. |
| return true; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool |
| DeduceTemplateArguments(ASTContext &Context, |
| const TemplateArgumentList &ParamList, |
| const TemplateArgumentList &ArgList, |
| llvm::SmallVectorImpl<TemplateArgument> &Deduced) { |
| assert(ParamList.size() == ArgList.size()); |
| for (unsigned I = 0, N = ParamList.size(); I != N; ++I) { |
| if (!DeduceTemplateArguments(Context, ParamList[I], ArgList[I], Deduced)) |
| return false; |
| } |
| return true; |
| } |
| |
| |
| TemplateArgumentList * |
| Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, |
| const TemplateArgumentList &TemplateArgs) { |
| // Deduce the template arguments for the partial specialization |
| llvm::SmallVector<TemplateArgument, 4> Deduced; |
| Deduced.resize(Partial->getTemplateParameters()->size()); |
| if (! ::DeduceTemplateArguments(Context, Partial->getTemplateArgs(), |
| TemplateArgs, Deduced)) |
| return 0; |
| |
| // FIXME: It isn't clear whether we want the diagnostic to point at |
| // the partial specialization itself or at the actual point of |
| // instantiation. |
| InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, |
| Deduced.data(), Deduced.size()); |
| if (Inst) |
| return 0; |
| |
| // C++ [temp.deduct.type]p2: |
| // [...] or if any template argument remains neither deduced nor |
| // explicitly specified, template argument deduction fails. |
| TemplateArgumentListBuilder Builder(Context); |
| for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { |
| if (Deduced[I].isNull()) |
| return 0; |
| |
| Builder.push_back(Deduced[I]); |
| } |
| |
| // Form the template argument list from the deduced template arguments. |
| TemplateArgumentList *DeducedArgumentList |
| = new (Context) TemplateArgumentList(Context, Builder, /*CopyArgs=*/true, |
| /*FlattenArgs=*/true); |
| |
| // Now that we have all of the deduced template arguments, take |
| // another pass through them to convert any integral template |
| // arguments to the appropriate type. |
| for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { |
| TemplateArgument &Arg = Deduced[I]; |
| if (Arg.getKind() == TemplateArgument::Integral) { |
| const NonTypeTemplateParmDecl *Parm |
| = cast<NonTypeTemplateParmDecl>(Partial->getTemplateParameters() |
| ->getParam(I)); |
| QualType T = InstantiateType(Parm->getType(), *DeducedArgumentList, |
| Parm->getLocation(), Parm->getDeclName()); |
| if (T.isNull()) // FIXME: DeducedArgumentList->Destroy(Context); |
| return 0; |
| |
| // FIXME: Make sure we didn't overflow our data type! |
| llvm::APSInt &Value = *Arg.getAsIntegral(); |
| unsigned AllowedBits = Context.getTypeSize(T); |
| if (Value.getBitWidth() != AllowedBits) |
| Value.extOrTrunc(AllowedBits); |
| Value.setIsSigned(T->isSignedIntegerType()); |
| Arg.setIntegralType(T); |
| } |
| |
| (*DeducedArgumentList)[I] = Arg; |
| } |
| |
| // 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. |
| ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); |
| const TemplateArgumentList &PartialTemplateArgs = Partial->getTemplateArgs(); |
| for (unsigned I = 0, N = PartialTemplateArgs.flat_size(); I != N; ++I) { |
| TemplateArgument InstArg = Instantiate(PartialTemplateArgs[I], |
| *DeducedArgumentList); |
| if (InstArg.isNull()) { |
| // FIXME: DeducedArgumentList->Destroy(Context); (or use RAII) |
| return 0; |
| } |
| |
| Decl *Param |
| = const_cast<Decl *>(ClassTemplate->getTemplateParameters()->getParam(I)); |
| if (isa<TemplateTypeParmDecl>(Param)) { |
| if (InstArg.getKind() != TemplateArgument::Type || |
| Context.getCanonicalType(InstArg.getAsType()) |
| != Context.getCanonicalType(TemplateArgs[I].getAsType())) |
| // FIXME: DeducedArgumentList->Destroy(Context); (or use RAII) |
| return 0; |
| } else if (NonTypeTemplateParmDecl *NTTP |
| = dyn_cast<NonTypeTemplateParmDecl>(Param)) { |
| QualType T = InstantiateType(NTTP->getType(), TemplateArgs, |
| NTTP->getLocation(), NTTP->getDeclName()); |
| if (T.isNull()) |
| // FIXME: DeducedArgumentList->Destroy(Context); (or use RAII) |
| return 0; |
| |
| if (InstArg.getKind() == TemplateArgument::Declaration || |
| InstArg.getKind() == TemplateArgument::Expression) { |
| // Turn the template argument into an expression, so that we can |
| // perform type checking on it and convert it to the type of the |
| // non-type template parameter. FIXME: Will this expression be |
| // leaked? It's hard to tell, since our ownership model for |
| // expressions in template arguments is so poor. |
| Expr *E = 0; |
| if (InstArg.getKind() == TemplateArgument::Declaration) { |
| NamedDecl *D = cast<NamedDecl>(InstArg.getAsDecl()); |
| QualType T = Context.OverloadTy; |
| if (ValueDecl *VD = dyn_cast<ValueDecl>(D)) |
| T = VD->getType().getNonReferenceType(); |
| E = new (Context) DeclRefExpr(D, T, InstArg.getLocation()); |
| } else { |
| E = InstArg.getAsExpr(); |
| } |
| |
| // Check that the template argument can be used to initialize |
| // the corresponding template parameter. |
| if (CheckTemplateArgument(NTTP, T, E, InstArg)) |
| return 0; |
| } |
| |
| switch (InstArg.getKind()) { |
| case TemplateArgument::Null: |
| assert(false && "Null template arguments cannot get here"); |
| return 0; |
| |
| case TemplateArgument::Type: |
| assert(false && "Type/value mismatch"); |
| return 0; |
| |
| case TemplateArgument::Integral: { |
| llvm::APSInt &Value = *InstArg.getAsIntegral(); |
| if (T->isIntegralType() || T->isEnumeralType()) { |
| QualType IntegerType = Context.getCanonicalType(T); |
| if (const EnumType *Enum = dyn_cast<EnumType>(IntegerType)) |
| IntegerType = Context.getCanonicalType( |
| Enum->getDecl()->getIntegerType()); |
| |
| // Check that an unsigned parameter does not receive a negative |
| // value. |
| if (IntegerType->isUnsignedIntegerType() |
| && (Value.isSigned() && Value.isNegative())) |
| return 0; |
| |
| // Check for truncation. If the number of bits in the |
| // instantiated template argument exceeds what is allowed by |
| // the type, template argument deduction fails. |
| unsigned AllowedBits = Context.getTypeSize(IntegerType); |
| if (Value.getActiveBits() > AllowedBits) |
| return 0; |
| |
| if (Value.getBitWidth() != AllowedBits) |
| Value.extOrTrunc(AllowedBits); |
| Value.setIsSigned(IntegerType->isSignedIntegerType()); |
| |
| // Check that the instantiated value is the same as the |
| // value provided as a template argument. |
| if (Value != *TemplateArgs[I].getAsIntegral()) |
| return 0; |
| } else if (T->isPointerType() || T->isMemberPointerType()) { |
| // Deal with NULL pointers that are used to initialize |
| // pointer and pointer-to-member non-type template |
| // parameters (C++0x). |
| if (TemplateArgs[I].getAsDecl()) |
| return 0; // Not a NULL declaration |
| |
| // Check that the integral value is 0, the NULL pointer |
| // constant. |
| if (Value != 0) |
| return 0; |
| } else |
| return 0; |
| break; |
| } |
| |
| case TemplateArgument::Declaration: |
| if (Context.getCanonicalDecl(InstArg.getAsDecl()) |
| != Context.getCanonicalDecl(TemplateArgs[I].getAsDecl())) |
| return 0; |
| break; |
| |
| case TemplateArgument::Expression: |
| // FIXME: Check equality of expressions |
| break; |
| } |
| } else { |
| assert(isa<TemplateTemplateParmDecl>(Param)); |
| // FIXME: Check template template arguments |
| } |
| } |
| |
| return DeducedArgumentList; |
| } |