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//===------- 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/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/SmallBitVector.h"
#include "TreeTransform.h"
#include <algorithm>
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,
/// \brief Whether we are performing template argument deduction for
/// parameters and arguments in a top-level template argument
TDF_TopLevelParameterTypeList = 0x10
};
}
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,
TemplateArgument Arg,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &Deduced);
/// \brief Whether template argument deduction for two reference parameters
/// resulted in the argument type, parameter type, or neither type being more
/// qualified than the other.
enum DeductionQualifierComparison {
NeitherMoreQualified = 0,
ParamMoreQualified,
ArgMoreQualified
};
/// \brief Stores the result of comparing two reference parameters while
/// performing template argument deduction for partial ordering of function
/// templates.
struct RefParamPartialOrderingComparison {
/// \brief Whether the parameter type is an rvalue reference type.
bool ParamIsRvalueRef;
/// \brief Whether the argument type is an rvalue reference type.
bool ArgIsRvalueRef;
/// \brief Whether the parameter or argument (or neither) is more qualified.
DeductionQualifierComparison Qualifiers;
};
static Sema::TemplateDeductionResult
DeduceTemplateArgumentsByTypeMatch(Sema &S,
TemplateParameterList *TemplateParams,
QualType Param,
QualType Arg,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &
Deduced,
unsigned TDF,
bool PartialOrdering = false,
SmallVectorImpl<RefParamPartialOrderingComparison> *
RefParamComparisons = 0);
static Sema::TemplateDeductionResult
DeduceTemplateArguments(Sema &S,
TemplateParameterList *TemplateParams,
const TemplateArgument *Params, unsigned NumParams,
const TemplateArgument *Args, unsigned NumArgs,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &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<ImplicitCastExpr>(E))
E = IC->getSubExpr();
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
return dyn_cast<NonTypeTemplateParmDecl>(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<NamedDecl>(X))
X = NX->getUnderlyingDecl();
if (NamedDecl *NY = dyn_cast<NamedDecl>(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;
}
llvm_unreachable("Invalid TemplateArgument Kind!");
}
/// \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,
SmallVectorImpl<DeducedTemplateArgument> &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,
SmallVectorImpl<DeducedTemplateArgument> &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,
SmallVectorImpl<DeducedTemplateArgument> &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,
SmallVectorImpl<DeducedTemplateArgument> &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<TemplateTemplateParmDecl>(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,
SmallVectorImpl<DeducedTemplateArgument> &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<TemplateSpecializationType>(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<RecordType>(Arg);
if (!RecordArg)
return Sema::TDK_NonDeducedMismatch;
ClassTemplateSpecializationDecl *SpecArg
= dyn_cast<ClassTemplateSpecializationDecl>(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:
case Type::TemplateTypeParm:
return true;
case Type::ConstantArray:
case Type::IncompleteArray:
case Type::VariableArray:
case Type::DependentSizedArray:
return IsPossiblyOpaquelyQualifiedType(
cast<ArrayType>(T)->getElementType());
default:
return false;
}
}
/// \brief Retrieve the depth and index of a template parameter.
static std::pair<unsigned, unsigned>
getDepthAndIndex(NamedDecl *ND) {
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ND))
return std::make_pair(TTP->getDepth(), TTP->getIndex());
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(ND))
return std::make_pair(NTTP->getDepth(), NTTP->getIndex());
TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(ND);
return std::make_pair(TTP->getDepth(), TTP->getIndex());
}
/// \brief Retrieve the depth and index of an unexpanded parameter pack.
static std::pair<unsigned, unsigned>
getDepthAndIndex(UnexpandedParameterPack UPP) {
if (const TemplateTypeParmType *TTP
= UPP.first.dyn_cast<const TemplateTypeParmType *>())
return std::make_pair(TTP->getDepth(), TTP->getIndex());
return getDepthAndIndex(UPP.first.get<NamedDecl *>());
}
/// \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<TemplateTypeParmDecl>(D))
return TemplateParameter(TTP);
else if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
return TemplateParameter(NTTP);
return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
}
/// \brief Prepare to perform template argument deduction for all of the
/// arguments in a set of argument packs.
static void PrepareArgumentPackDeduction(Sema &S,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
ArrayRef<unsigned> PackIndices,
SmallVectorImpl<DeducedTemplateArgument> &SavedPacks,
SmallVectorImpl<
SmallVector<DeducedTemplateArgument, 4> > &NewlyDeducedPacks) {
// Save the deduced template arguments for each parameter pack expanded
// by this pack expansion, then clear out the deduction.
for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) {
// Save the previously-deduced argument pack, then clear it out so that we
// can deduce a new argument pack.
SavedPacks[I] = Deduced[PackIndices[I]];
Deduced[PackIndices[I]] = TemplateArgument();
// If the template arugment pack was explicitly specified, add that to
// the set of deduced arguments.
const TemplateArgument *ExplicitArgs;
unsigned NumExplicitArgs;
if (NamedDecl *PartiallySubstitutedPack
= S.CurrentInstantiationScope->getPartiallySubstitutedPack(
&ExplicitArgs,
&NumExplicitArgs)) {
if (getDepthAndIndex(PartiallySubstitutedPack).second == PackIndices[I])
NewlyDeducedPacks[I].append(ExplicitArgs,
ExplicitArgs + NumExplicitArgs);
}
}
}
/// \brief Finish template argument deduction for a set of argument packs,
/// producing the argument packs and checking for consistency with prior
/// deductions.
static Sema::TemplateDeductionResult
FinishArgumentPackDeduction(Sema &S,
TemplateParameterList *TemplateParams,
bool HasAnyArguments,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
ArrayRef<unsigned> PackIndices,
SmallVectorImpl<DeducedTemplateArgument> &SavedPacks,
SmallVectorImpl<
SmallVector<DeducedTemplateArgument, 4> > &NewlyDeducedPacks,
TemplateDeductionInfo &Info) {
// 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;
}
return Sema::TDK_Success;
}
/// \brief Deduce the template arguments by comparing the list of parameter
/// types to the list of argument types, as in the parameter-type-lists of
/// function types (C++ [temp.deduct.type]p10).
///
/// \param S The semantic analysis object within which we are deducing
///
/// \param TemplateParams The template parameters that we are deducing
///
/// \param Params The list of parameter types
///
/// \param NumParams The number of types in \c Params
///
/// \param Args The list of argument types
///
/// \param NumArgs The number of types in \c Args
///
/// \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.
///
/// \param PartialOrdering If true, we are performing template argument
/// deduction for during partial ordering for a call
/// (C++0x [temp.deduct.partial]).
///
/// \param RefParamComparisons If we're performing template argument deduction
/// in the context of partial ordering, the set of qualifier comparisons.
///
/// \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 QualType *Params, unsigned NumParams,
const QualType *Args, unsigned NumArgs,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
unsigned TDF,
bool PartialOrdering = false,
SmallVectorImpl<RefParamPartialOrderingComparison> *
RefParamComparisons = 0) {
// Fast-path check to see if we have too many/too few arguments.
if (NumParams != NumArgs &&
!(NumParams && isa<PackExpansionType>(Params[NumParams - 1])) &&
!(NumArgs && isa<PackExpansionType>(Args[NumArgs - 1])))
return Sema::TDK_NonDeducedMismatch;
// C++0x [temp.deduct.type]p10:
// Similarly, if P has a form that contains (T), then each parameter type
// Pi of the respective parameter-type- list of P is compared with the
// corresponding parameter type Ai of the corresponding parameter-type-list
// of A. [...]
unsigned ArgIdx = 0, ParamIdx = 0;
for (; ParamIdx != NumParams; ++ParamIdx) {
// Check argument types.
const PackExpansionType *Expansion
= dyn_cast<PackExpansionType>(Params[ParamIdx]);
if (!Expansion) {
// Simple case: compare the parameter and argument types at this point.
// Make sure we have an argument.
if (ArgIdx >= NumArgs)
return Sema::TDK_NonDeducedMismatch;
if (isa<PackExpansionType>(Args[ArgIdx])) {
// C++0x [temp.deduct.type]p22:
// If the original function parameter associated with A is a function
// parameter pack and the function parameter associated with P is not
// a function parameter pack, then template argument deduction fails.
return Sema::TDK_NonDeducedMismatch;
}
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
Params[ParamIdx], Args[ArgIdx],
Info, Deduced, TDF,
PartialOrdering,
RefParamComparisons))
return Result;
++ArgIdx;
continue;
}
// C++0x [temp.deduct.type]p5:
// The non-deduced contexts are:
// - A function parameter pack that does not occur at the end of the
// parameter-declaration-clause.
if (ParamIdx + 1 < NumParams)
return Sema::TDK_Success;
// C++0x [temp.deduct.type]p10:
// If the parameter-declaration corresponding to Pi is a function
// parameter pack, then the type of its declarator- id is compared with
// each remaining parameter type in the parameter-type-list of A. Each
// comparison deduces template arguments for subsequent positions in the
// template parameter packs expanded by the function parameter pack.
// Compute the set of template parameter indices that correspond to
// parameter packs expanded by the pack expansion.
SmallVector<unsigned, 2> PackIndices;
QualType Pattern = Expansion->getPattern();
{
llvm::SmallBitVector SawIndices(TemplateParams->size());
SmallVector<UnexpandedParameterPack, 2> 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?");
// 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).
SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2>
NewlyDeducedPacks(PackIndices.size());
SmallVector<DeducedTemplateArgument, 2>
SavedPacks(PackIndices.size());
PrepareArgumentPackDeduction(S, Deduced, PackIndices, SavedPacks,
NewlyDeducedPacks);
bool HasAnyArguments = false;
for (; ArgIdx < NumArgs; ++ArgIdx) {
HasAnyArguments = true;
// Deduce template arguments from the pattern.
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
Args[ArgIdx], Info, Deduced,
TDF, PartialOrdering,
RefParamComparisons))
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();
}
}
}
// Build argument packs for each of the parameter packs expanded by this
// pack expansion.
if (Sema::TemplateDeductionResult Result
= FinishArgumentPackDeduction(S, TemplateParams, HasAnyArguments,
Deduced, PackIndices, SavedPacks,
NewlyDeducedPacks, Info))
return Result;
}
// Make sure we don't have any extra arguments.
if (ArgIdx < NumArgs)
return Sema::TDK_NonDeducedMismatch;
return Sema::TDK_Success;
}
/// \brief Determine whether the parameter has qualifiers that are either
/// inconsistent with or a superset of the argument's qualifiers.
static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
QualType ArgType) {
Qualifiers ParamQs = ParamType.getQualifiers();
Qualifiers ArgQs = ArgType.getQualifiers();
if (ParamQs == ArgQs)
return false;
// Mismatched (but not missing) Objective-C GC attributes.
if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
ParamQs.hasObjCGCAttr())
return true;
// Mismatched (but not missing) address spaces.
if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
ParamQs.hasAddressSpace())
return true;
// Mismatched (but not missing) Objective-C lifetime qualifiers.
if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
ParamQs.hasObjCLifetime())
return true;
// CVR qualifier superset.
return (ParamQs.getCVRQualifiers() != ArgQs.getCVRQualifiers()) &&
((ParamQs.getCVRQualifiers() | ArgQs.getCVRQualifiers())
== ParamQs.getCVRQualifiers());
}
/// \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.
///
/// \param PartialOrdering Whether we're performing template argument deduction
/// in the context of partial ordering (C++0x [temp.deduct.partial]).
///
/// \param RefParamComparisons If we're performing template argument deduction
/// in the context of partial ordering, the set of qualifier comparisons.
///
/// \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
DeduceTemplateArgumentsByTypeMatch(Sema &S,
TemplateParameterList *TemplateParams,
QualType ParamIn, QualType ArgIn,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
unsigned TDF,
bool PartialOrdering,
SmallVectorImpl<RefParamPartialOrderingComparison> *
RefParamComparisons) {
// 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);
// If the argument type is a pack expansion, look at its pattern.
// This isn't explicitly called out
if (const PackExpansionType *ArgExpansion
= dyn_cast<PackExpansionType>(Arg))
Arg = ArgExpansion->getPattern();
if (PartialOrdering) {
// 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.
const ReferenceType *ParamRef = Param->getAs<ReferenceType>();
if (ParamRef)
Param = ParamRef->getPointeeType();
// - If A is a reference type, A is replaced by the type referred to.
const ReferenceType *ArgRef = Arg->getAs<ReferenceType>();
if (ArgRef)
Arg = ArgRef->getPointeeType();
if (RefParamComparisons && ParamRef && ArgRef) {
// 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.
RefParamPartialOrderingComparison Comparison;
Comparison.ParamIsRvalueRef = ParamRef->getAs<RValueReferenceType>();
Comparison.ArgIsRvalueRef = ArgRef->getAs<RValueReferenceType>();
Comparison.Qualifiers = NeitherMoreQualified;
Qualifiers ParamQuals = Param.getQualifiers();
Qualifiers ArgQuals = Arg.getQualifiers();
if (ParamQuals.isStrictSupersetOf(ArgQuals))
Comparison.Qualifiers = ParamMoreQualified;
else if (ArgQuals.isStrictSupersetOf(ParamQuals))
Comparison.Qualifiers = ArgMoreQualified;
RefParamComparisons->push_back(Comparison);
}
// 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();
} else {
// 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.getCVRQualifiers());
Param = S.Context.getQualifiedType(UnqualParam, Quals);
}
if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
// C++0x [temp.deduct.type]p10:
// If P and A are function types that originated from deduction when
// taking the address of a function template (14.8.2.2) or when deducing
// template arguments from a function declaration (14.8.2.6) and Pi and
// Ai are parameters of the top-level parameter-type-list of P and A,
// respectively, Pi is adjusted if it is an rvalue reference to a
// cv-unqualified template parameter and Ai is an lvalue reference, in
// which case the type of Pi is changed to be the template parameter
// type (i.e., T&& is changed to simply T). [ Note: As a result, when
// Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
// deduced as X&. - end note ]
TDF &= ~TDF_TopLevelParameterTypeList;
if (const RValueReferenceType *ParamRef
= Param->getAs<RValueReferenceType>()) {
if (isa<TemplateTypeParmType>(ParamRef->getPointeeType()) &&
!ParamRef->getPointeeType().getQualifiers())
if (Arg->isLValueReferenceType())
Param = ParamRef->getPointeeType();
}
}
}
// 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<TemplateTypeParmType>()) {
// Just skip any attempts to deduce from a placeholder type.
if (Arg->isPlaceholderType())
return Sema::TDK_Success;
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.
if (isa<ArrayType>(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 (!(TDF & TDF_IgnoreQualifiers) &&
hasInconsistentOrSupersetQualifiersOf(Param, Arg)) {
Info.Param = cast<TemplateTypeParmDecl>(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;
// Remove any qualifiers on the parameter from the deduced type.
// We checked the qualifiers for consistency above.
Qualifiers DeducedQs = DeducedType.getQualifiers();
Qualifiers ParamQs = Param.getQualifiers();
DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers());
if (ParamQs.hasObjCGCAttr())
DeducedQs.removeObjCGCAttr();
if (ParamQs.hasAddressSpace())
DeducedQs.removeAddressSpace();
if (ParamQs.hasObjCLifetime())
DeducedQs.removeObjCLifetime();
// Objective-C ARC:
// If template deduction would produce a lifetime qualifier on a type
// that is not a lifetime type, template argument deduction fails.
if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
!DeducedType->isDependentType()) {
Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
Info.FirstArg = TemplateArgument(Param);
Info.SecondArg = TemplateArgument(Arg);
return Sema::TDK_Underqualified;
}
// Objective-C ARC:
// If template deduction would produce an argument type with lifetime type
// but no lifetime qualifier, the __strong lifetime qualifier is inferred.
if (S.getLangOpts().ObjCAutoRefCount &&
DeducedType->isObjCLifetimeType() &&
!DeducedQs.hasObjCLifetime())
DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong);
DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(),
DeducedQs);
if (RecanonicalizeArg)
DeducedType = S.Context.getCanonicalType(DeducedType);
DeducedTemplateArgument NewDeduced(DeducedType);
DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
Deduced[Index],
NewDeduced);
if (Result.isNull()) {
Info.Param = cast<TemplateTypeParmDecl>(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);
// If the parameter is an already-substituted template parameter
// pack, do nothing: we don't know which of its arguments to look
// at, so we have to wait until all of the parameter packs in this
// expansion have arguments.
if (isa<SubstTemplateTypeParmPackType>(Param))
return Sema::TDK_Success;
// Check the cv-qualifiers on the parameter and argument types.
if (!(TDF & TDF_IgnoreQualifiers)) {
if (TDF & TDF_ParamWithReferenceType) {
if (hasInconsistentOrSupersetQualifiersOf(Param, Arg))
return Sema::TDK_NonDeducedMismatch;
} else if (!IsPossiblyOpaquelyQualifiedType(Param)) {
if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
return Sema::TDK_NonDeducedMismatch;
}
// 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;
}
} else if (!Param->isDependentType() &&
Param.getUnqualifiedType() == Arg.getUnqualifiedType()) {
return Sema::TDK_Success;
}
switch (Param->getTypeClass()) {
// Non-canonical types cannot appear here.
#define NON_CANONICAL_TYPE(Class, Base) \
case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class);
#define TYPE(Class, Base)
#include "clang/AST/TypeNodes.def"
case Type::TemplateTypeParm:
case Type::SubstTemplateTypeParmPack:
llvm_unreachable("Type nodes handled above");
// These types cannot be dependent, so simply check whether the types are
// the same.
case Type::Builtin:
case Type::VariableArray:
case Type::Vector:
case Type::FunctionNoProto:
case Type::Record:
case Type::Enum:
case Type::ObjCObject:
case Type::ObjCInterface:
case Type::ObjCObjectPointer: {
if (TDF & TDF_SkipNonDependent)
return Sema::TDK_Success;
if (TDF & TDF_IgnoreQualifiers) {
Param = Param.getUnqualifiedType();
Arg = Arg.getUnqualifiedType();
}
return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch;
}
// _Complex T [placeholder extension]
case Type::Complex:
if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
cast<ComplexType>(Param)->getElementType(),
ComplexArg->getElementType(),
Info, Deduced, TDF);
return Sema::TDK_NonDeducedMismatch;
// _Atomic T [extension]
case Type::Atomic:
if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>())
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
cast<AtomicType>(Param)->getValueType(),
AtomicArg->getValueType(),
Info, Deduced, TDF);
return Sema::TDK_NonDeducedMismatch;
// T *
case Type::Pointer: {
QualType PointeeType;
if (const PointerType *PointerArg = Arg->getAs<PointerType>()) {
PointeeType = PointerArg->getPointeeType();
} else if (const ObjCObjectPointerType *PointerArg
= Arg->getAs<ObjCObjectPointerType>()) {
PointeeType = PointerArg->getPointeeType();
} else {
return Sema::TDK_NonDeducedMismatch;
}
unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass);
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
cast<PointerType>(Param)->getPointeeType(),
PointeeType,
Info, Deduced, SubTDF);
}
// T &
case Type::LValueReference: {
const LValueReferenceType *ReferenceArg = Arg->getAs<LValueReferenceType>();
if (!ReferenceArg)
return Sema::TDK_NonDeducedMismatch;
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
cast<LValueReferenceType>(Param)->getPointeeType(),
ReferenceArg->getPointeeType(), Info, Deduced, 0);
}
// T && [C++0x]
case Type::RValueReference: {
const RValueReferenceType *ReferenceArg = Arg->getAs<RValueReferenceType>();
if (!ReferenceArg)
return Sema::TDK_NonDeducedMismatch;
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
cast<RValueReferenceType>(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 DeduceTemplateArgumentsByTypeMatch(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 DeduceTemplateArgumentsByTypeMatch(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
= DeduceTemplateArgumentsByTypeMatch(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<ConstantArrayType>(ArrayArg)) {
llvm::APSInt Size(ConstantArrayArg->getSize());
return DeduceNonTypeTemplateArgument(S, NTTP, Size,
S.Context.getSizeType(),
/*ArrayBound=*/true,
Info, Deduced);
}
if (const DependentSizedArrayType *DependentArrayArg
= dyn_cast<DependentSizedArrayType>(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: {
unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
const FunctionProtoType *FunctionProtoArg =
dyn_cast<FunctionProtoType>(Arg);
if (!FunctionProtoArg)
return Sema::TDK_NonDeducedMismatch;
const FunctionProtoType *FunctionProtoParam =
cast<FunctionProtoType>(Param);
if (FunctionProtoParam->getTypeQuals()
!= FunctionProtoArg->getTypeQuals() ||
FunctionProtoParam->getRefQualifier()
!= FunctionProtoArg->getRefQualifier() ||
FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
return Sema::TDK_NonDeducedMismatch;
// Check return types.
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
FunctionProtoParam->getResultType(),
FunctionProtoArg->getResultType(),
Info, Deduced, 0))
return Result;
return DeduceTemplateArguments(S, TemplateParams,
FunctionProtoParam->arg_type_begin(),
FunctionProtoParam->getNumArgs(),
FunctionProtoArg->arg_type_begin(),
FunctionProtoArg->getNumArgs(),
Info, Deduced, SubTDF);
}
case Type::InjectedClassName: {
// Treat a template's injected-class-name as if the template
// specialization type had been used.
Param = cast<InjectedClassNameType>(Param)
->getInjectedSpecializationType();
assert(isa<TemplateSpecializationType>(Param) &&
"injected class name is not a template specialization type");
// fall through
}
// template-name<T> (where template-name refers to a class template)
// template-name<i>
// TT<T>
// TT<i>
// TT<>
case Type::TemplateSpecialization: {
const TemplateSpecializationType *SpecParam
= cast<TemplateSpecializationType>(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<RecordType>()) {
// 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<const RecordType *, 8> Visited;
SmallVector<const RecordType *, 8> ToVisit;
ToVisit.push_back(RecordT);
bool Successful = false;
SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(),
Deduced.end());
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.clear();
DeducedOrig.append(Deduced.begin(), Deduced.end());
}
else
Deduced = DeducedOrig;
}
// Visit base classes
CXXRecordDecl *Next = cast<CXXRecordDecl>(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<RecordType>());
}
}
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<MemberPointerType>(Param);
const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
if (!MemPtrArg)
return Sema::TDK_NonDeducedMismatch;
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
MemPtrParam->getPointeeType(),
MemPtrArg->getPointeeType(),
Info, Deduced,
TDF & TDF_IgnoreQualifiers))
return Result;
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
QualType(MemPtrParam->getClass(), 0),
QualType(MemPtrArg->getClass(), 0),
Info, Deduced,
TDF & TDF_IgnoreQualifiers);
}
// (clang extension)
//
// type(^)(T)
// T(^)()
// T(^)(T)
case Type::BlockPointer: {
const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);
if (!BlockPtrArg)
return Sema::TDK_NonDeducedMismatch;
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
BlockPtrParam->getPointeeType(),
BlockPtrArg->getPointeeType(),
Info, Deduced, 0);
}
// (clang extension)
//
// T __attribute__(((ext_vector_type(<integral constant>))))
case Type::ExtVector: {
const ExtVectorType *VectorParam = cast<ExtVectorType>(Param);
if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
// Make sure that the vectors have the same number of elements.
if (VectorParam->getNumElements() != VectorArg->getNumElements())
return Sema::TDK_NonDeducedMismatch;
// Perform deduction on the element types.
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
VectorParam->getElementType(),
VectorArg->getElementType(),
Info, Deduced, TDF);
}
if (const DependentSizedExtVectorType *VectorArg
= dyn_cast<DependentSizedExtVectorType>(Arg)) {
// We can't check the number of elements, since the argument has a
// dependent number of elements. This can only occur during partial
// ordering.
// Perform deduction on the element types.
return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
VectorParam->getElementType(),
VectorArg->getElementType(),
Info, Deduced, TDF);
}
return Sema::TDK_NonDeducedMismatch;
}
// (clang extension)
//
// T __attribute__(((ext_vector_type(N))))
case Type::DependentSizedExtVector: {
const DependentSizedExtVectorType *VectorParam
= cast<DependentSizedExtVectorType>(Param);
if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
// Perform deduction on the element types.
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
VectorParam->getElementType(),
VectorArg->getElementType(),
Info, Deduced, TDF))
return Result;
// Perform deduction on the vector size, if we can.
NonTypeTemplateParmDecl *NTTP
= getDeducedParameterFromExpr(VectorParam->getSizeExpr());
if (!NTTP)
return Sema::TDK_Success;
llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
ArgSize = VectorArg->getNumElements();
return DeduceNonTypeTemplateArgument(S, NTTP, ArgSize, S.Context.IntTy,
false, Info, Deduced);
}
if (const DependentSizedExtVectorType *VectorArg
= dyn_cast<DependentSizedExtVectorType>(Arg)) {
// Perform deduction on the element types.
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
VectorParam->getElementType(),
VectorArg->getElementType(),
Info, Deduced, TDF))
return Result;
// Perform deduction on the vector size, if we can.
NonTypeTemplateParmDecl *NTTP
= getDeducedParameterFromExpr(VectorParam->getSizeExpr());
if (!NTTP)
return Sema::TDK_Success;
return DeduceNonTypeTemplateArgument(S, NTTP, VectorArg->getSizeExpr(),
Info, Deduced);
}
return Sema::TDK_NonDeducedMismatch;
}
case Type::TypeOfExpr:
case Type::TypeOf:
case Type::DependentName:
case Type::UnresolvedUsing:
case Type::Decltype:
case Type::UnaryTransform:
case Type::Auto:
case Type::DependentTemplateSpecialization:
case Type::PackExpansion:
// No template argument deduction for these types
return Sema::TDK_Success;
}
llvm_unreachable("Invalid Type Class!");
}
static Sema::TemplateDeductionResult
DeduceTemplateArguments(Sema &S,
TemplateParameterList *TemplateParams,
const TemplateArgument &Param,
TemplateArgument Arg,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
// If the template argument is a pack expansion, perform template argument
// deduction against the pattern of that expansion. This only occurs during
// partial ordering.
if (Arg.isPackExpansion())
Arg = Arg.getPackExpansionPattern();
switch (Param.getKind()) {
case TemplateArgument::Null:
llvm_unreachable("Null template argument in parameter list");
case TemplateArgument::Type:
if (Arg.getKind() == TemplateArgument::Type)
return DeduceTemplateArgumentsByTypeMatch(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");
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!");
}
llvm_unreachable("Invalid TemplateArgument Kind!");
}
/// \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 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,
SmallVectorImpl<DeducedTemplateArgument> &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 <T> or <i>, 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) {
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_NonDeducedMismatch
: Sema::TDK_Success;
if (Args[ArgIdx].isPackExpansion()) {
// FIXME: We follow the logic of C++0x [temp.deduct.type]p22 here,
// but applied to pack expansions that are template arguments.
return Sema::TDK_NonDeducedMismatch;
}
// 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.
SmallVector<unsigned, 2> PackIndices;
{
llvm::SmallBitVector SawIndices(TemplateParams->size());
SmallVector<UnexpandedParameterPack, 2> 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.
SmallVector<DeducedTemplateArgument, 2>
SavedPacks(PackIndices.size());
SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2>
NewlyDeducedPacks(PackIndices.size());
PrepareArgumentPackDeduction(S, Deduced, PackIndices, SavedPacks,
NewlyDeducedPacks);
// 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).
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.
if (Sema::TemplateDeductionResult Result
= FinishArgumentPackDeduction(S, TemplateParams, HasAnyArguments,
Deduced, PackIndices, SavedPacks,
NewlyDeducedPacks, Info))
return Result;
}
// If there is an argument remaining, then we had too many arguments.
if (NumberOfArgumentsMustMatch &&
hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs))
return Sema::TDK_NonDeducedMismatch;
return Sema::TDK_Success;
}
static Sema::TemplateDeductionResult
DeduceTemplateArguments(Sema &S,
TemplateParameterList *TemplateParams,
const TemplateArgumentList &ParamList,
const TemplateArgumentList &ArgList,
TemplateDeductionInfo &Info,
SmallVectorImpl<DeducedTemplateArgument> &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:
llvm_unreachable("Comparing NULL template argument");
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;
}
llvm_unreachable("Invalid TemplateArgument Kind!");
}
/// \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");
case TemplateArgument::Type:
return TemplateArgumentLoc(Arg,
S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));
case TemplateArgument::Declaration: {
Expr *E
= S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
.takeAs<Expr>();
return TemplateArgumentLoc(TemplateArgument(E), E);
}
case TemplateArgument::Integral: {
Expr *E
= S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>();
return TemplateArgumentLoc(TemplateArgument(E), E);
}
case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion: {
NestedNameSpecifierLocBuilder Builder;
TemplateName Template = Arg.getAsTemplate();
if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
Builder.MakeTrivial(S.Context, DTN->getQualifier(), Loc);
else if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
Builder.MakeTrivial(S.Context, QTN->getQualifier(), Loc);
if (Arg.getKind() == TemplateArgument::Template)
return TemplateArgumentLoc(Arg,
Builder.getWithLocInContext(S.Context),
Loc);
return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(S.Context),
Loc, Loc);
}
case TemplateArgument::Expression:
return TemplateArgumentLoc(Arg, Arg.getAsExpr());
case TemplateArgument::Pack:
return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
}
llvm_unreachable("Invalid TemplateArgument Kind!");
}
/// \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,
unsigned ArgumentPackIndex,
TemplateDeductionInfo &Info,
bool InFunctionTemplate,
SmallVectorImpl<TemplateArgument> &Output) {
if (Arg.getKind() == TemplateArgument::Pack) {
// This is a template argument pack, so check each of its arguments against
// the template parameter.
SmallVector<TemplateArgument, 2> 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, PackedArgsBuilder.size(),
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.
Output.push_back(TemplateArgument::CreatePackCopy(S.Context,
PackedArgsBuilder.data(),
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(),
ArgumentPackIndex,
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,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
TemplateDeductionInfo &Info) {
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(S, Sema::Unevaluated);
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.
SmallVector<TemplateArgument, 4> 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<NonTypeTemplateParmDecl>(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, 0, 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<NamedDecl *>(
Partial->getTemplateParameters()->getParam(ParamIdx));
Info.Param = makeTemplateParameter(Param);
Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
return Sema::TDK_SubstitutionFailure;
}
SmallVector<TemplateArgument, 4> 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).
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
SFINAETrap Trap(*this);
SmallVector<DeducedTemplateArgument, 4> 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<TemplateSpecializationType>())
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,
TemplateArgumentListInfo &ExplicitTemplateArgs,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
SmallVectorImpl<QualType> &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;
}
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
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.
SmallVector<TemplateArgument, 4> 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());
// If we deduced template arguments for a template parameter pack,
// note that the template argument pack is partially substituted and record
// the explicit template arguments. They'll be used as part of deduction
// for this template parameter pack.
for (unsigned I = 0, N = Builder.size(); I != N; ++I) {
const TemplateArgument &Arg = Builder[I];
if (Arg.getKind() == TemplateArgument::Pack) {
CurrentInstantiationScope->SetPartiallySubstitutedPack(
TemplateParams->getParam(I),
Arg.pack_begin(),
Arg.pack_size());
break;
}
}
const FunctionProtoType *Proto
= Function->getType()->getAs<FunctionProtoType>();
assert(Proto && "Function template does not have a prototype?");
// Instantiate the types of each of the function parameters given the
// explicitly-specified template arguments. If the function has a trailing
// return type, substitute it after the arguments to ensure we substitute
// in lexical order.
if (Proto->hasTrailingReturn() &&
SubstParmTypes(Function->getLocation(),
Function->param_begin(), Function->getNumParams(),
MultiLevelTemplateArgumentList(*ExplicitArgumentList),
ParamTypes))
return TDK_SubstitutionFailure;
// Instantiate the return type.
// FIXME: exception-specifications?
QualType ResultType
= SubstType(Proto->getResultType(),
MultiLevelTemplateArgumentList(*ExplicitArgumentList),
Function->getTypeSpecStartLoc(),
Function->getDeclName());
if (ResultType.isNull() || Trap.hasErrorOccurred())
return TDK_SubstitutionFailure;
// Instantiate the types of each of the function parameters given the
// explicitly-specified template arguments if we didn't do so earlier.
if (!Proto->hasTrailingReturn() &&
SubstParmTypes(Function->getLocation(),
Function->param_begin(), Function->getNumParams(),
MultiLevelTemplateArgumentList(*ExplicitArgumentList),
ParamTypes))
return TDK_SubstitutionFailure;
if (FunctionType) {
*FunctionType = BuildFunctionType(ResultType,
ParamTypes.data(), ParamTypes.size(),
Proto->isVariadic(),
Proto->hasTrailingReturn(),
Proto->getTypeQuals(),
Proto->getRefQualifier(),
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. Explicitly-specified
// parameter packs, however, will be set to NULL since the deduction
// mechanisms handle explicitly-specified argument packs directly.
Deduced.reserve(TemplateParams->size());
for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) {
const TemplateArgument &Arg = ExplicitArgumentList->get(I);
if (Arg.getKind() == TemplateArgument::Pack)
Deduced.push_back(DeducedTemplateArgument());
else
Deduced.push_back(Arg);
}
return TDK_Success;
}
/// \brief Check whether the deduced argument type for a call to a function
/// template matches the actual argument type per C++ [temp.deduct.call]p4.
static bool
CheckOriginalCallArgDeduction(Sema &S, Sema::OriginalCallArg OriginalArg,
QualType DeducedA) {
ASTContext &Context = S.Context;
QualType A = OriginalArg.OriginalArgType;
QualType OriginalParamType = OriginalArg.OriginalParamType;
// Check for type equality (top-level cv-qualifiers are ignored).
if (Context.hasSameUnqualifiedType(A, DeducedA))
return false;
// Strip off references on the argument types; they aren't needed for
// the following checks.
if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>())
DeducedA = DeducedARef->getPointeeType();
if (const ReferenceType *ARef = A->getAs<ReferenceType>())
A = ARef->getPointeeType();
// C++ [temp.deduct.call]p4:
// [...] However, there are three cases that allow a difference:
// - 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 (const ReferenceType *OriginalParamRef
= OriginalParamType->getAs<ReferenceType>()) {
// We don't want to keep the reference around any more.
OriginalParamType = OriginalParamRef->getPointeeType();
Qualifiers AQuals = A.getQualifiers();
Qualifiers DeducedAQuals = DeducedA.getQualifiers();
if (AQuals == DeducedAQuals) {
// Qualifiers match; there's nothing to do.
} else if (!DeducedAQuals.compatiblyIncludes(AQuals)) {
return true;
} else {
// Qualifiers are compatible, so have the argument type adopt the
// deduced argument type's qualifiers as if we had performed the
// qualification conversion.
A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals);
}
}
// - The transformed A can be another pointer or pointer to member
// type that can be converted to the deduced A via a qualification
// conversion.
//
// Also allow conversions which merely strip [[noreturn]] from function types
// (recursively) as an extension.
// FIXME: Currently, this doesn't place nicely with qualfication conversions.
bool ObjCLifetimeConversion = false;
QualType ResultTy;
if ((A->isAnyPointerType() || A->isMemberPointerType()) &&
(S.IsQualificationConversion(A, DeducedA, false,
ObjCLifetimeConversion) ||
S.IsNoReturnConversion(A, DeducedA, ResultTy)))
return false;
// - 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 (const PointerType *OriginalParamPtr
= OriginalParamType->getAs<PointerType>()) {
if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) {
if (const PointerType *APtr = A->getAs<PointerType>()) {
if (A->getPointeeType()->isRecordType()) {
OriginalParamType = OriginalParamPtr->getPointeeType();
DeducedA = DeducedAPtr->getPointeeType();
A = APtr->getPointeeType();
}
}
}
}
if (Context.hasSameUnqualifiedType(A, DeducedA))
return false;
if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) &&
S.IsDerivedFrom(A, DeducedA))
return false;
return true;
}
/// \brief Finish template argument deduction for a function template,
/// checking the deduced template arguments for completeness and forming
/// the function template specialization.
///
/// \param OriginalCallArgs If non-NULL, the original call arguments against
/// which the deduced argument types should be compared.
Sema::TemplateDeductionResult
Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate,
SmallVectorImpl<DeducedTemplateArgument> &Deduced,
unsigned NumExplicitlySpecified,
FunctionDecl *&Specialization,
TemplateDeductionInfo &Info,
SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs) {
TemplateParameterList *TemplateParams
= FunctionTemplate->getTemplateParameters();
// Unevaluated SFINAE context.
EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
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.
SmallVector<TemplateArgument, 4> 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<NonTypeTemplateParmDecl>(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, 0, 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()) {
// We may have had explicitly-specified template arguments for this
// template parameter pack. If so, our empty deduction extends the
// explicitly-specified set (C++0x [temp.arg.explicit]p9).
const TemplateArgument *ExplicitArgs;
unsigned NumExplicitArgs;
if (CurrentInstantiationScope->getPartiallySubstitutedPack(&ExplicitArgs,
&NumExplicitArgs)
== Param)