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-rw-r--r--clang/lib/Sema/SemaTemplateDeduction.cpp262
1 files changed, 218 insertions, 44 deletions
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index 0df2899855c..e762d341176 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -87,6 +87,15 @@ DeduceTemplateArguments(Sema &S,
static Sema::TemplateDeductionResult
DeduceTemplateArguments(Sema &S,
TemplateParameterList *TemplateParams,
+ QualType Param,
+ QualType Arg,
+ TemplateDeductionInfo &Info,
+ llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced,
+ unsigned TDF);
+
+static Sema::TemplateDeductionResult
+DeduceTemplateArguments(Sema &S,
+ TemplateParameterList *TemplateParams,
const TemplateArgument *Params, unsigned NumParams,
const TemplateArgument *Args, unsigned NumArgs,
TemplateDeductionInfo &Info,
@@ -469,6 +478,209 @@ static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
}
}
+/// \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());
+
+ NamedDecl *ND = UPP.first.get<NamedDecl *>();
+ 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 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 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.
+///
+/// \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,
+ llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced,
+ unsigned TDF) {
+ // FIXME: Fast-path check with NumParams != NumArgs and there are no
+ // pack expansions around.
+
+ // 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_TooFewArguments;
+
+ if (Sema::TemplateDeductionResult Result
+ = DeduceTemplateArguments(S, TemplateParams,
+ Params[ParamIdx],
+ Args[ArgIdx],
+ Info, Deduced, TDF))
+ return Result;
+
+ ++ArgIdx;
+ continue;
+ }
+
+ // 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.
+ llvm::SmallVector<unsigned, 2> PackIndices;
+ QualType Pattern = Expansion->getPattern();
+ {
+ llvm::BitVector SawIndices(TemplateParams->size());
+ llvm::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?");
+
+ // Save the deduced template arguments for each parameter pack expanded
+ // by this pack expansion, then clear out the deduction.
+ llvm::SmallVector<DeducedTemplateArgument, 2>
+ SavedPacks(PackIndices.size());
+ for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) {
+ SavedPacks[I] = Deduced[PackIndices[I]];
+ Deduced[PackIndices[I]] = DeducedTemplateArgument();
+ }
+
+ // Keep track of the deduced template arguments for each parameter pack
+ // expanded by this pack expansion (the outer index) and for each
+ // template argument (the inner SmallVectors).
+ llvm::SmallVector<llvm::SmallVector<DeducedTemplateArgument, 4>, 2>
+ NewlyDeducedPacks(PackIndices.size());
+ bool HasAnyArguments = false;
+ for (; ArgIdx < NumArgs; ++ArgIdx) {
+ 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();
+ }
+ }
+ }
+
+ // 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;
+ }
+ }
+
+ // Make sure we don't have any extra arguments.
+ if (ArgIdx < NumArgs)
+ return Sema::TDK_TooManyArguments;
+
+ return Sema::TDK_Success;
+}
+
/// \brief Deduce the template arguments by comparing the parameter type and
/// the argument type (C++ [temp.deduct.type]).
///
@@ -740,9 +952,6 @@ DeduceTemplateArguments(Sema &S,
FunctionProtoArg->getTypeQuals())
return Sema::TDK_NonDeducedMismatch;
- if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs())
- return Sema::TDK_NonDeducedMismatch;
-
if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
return Sema::TDK_NonDeducedMismatch;
@@ -754,18 +963,12 @@ DeduceTemplateArguments(Sema &S,
Info, Deduced, 0))
return Result;
- for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) {
- // Check argument types.
- // FIXME: Variadic templates.
- if (Sema::TemplateDeductionResult Result
- = DeduceTemplateArguments(S, TemplateParams,
- FunctionProtoParam->getArgType(I),
- FunctionProtoArg->getArgType(I),
- Info, Deduced, 0))
- return Result;
- }
-
- return Sema::TDK_Success;
+ return DeduceTemplateArguments(S, TemplateParams,
+ FunctionProtoParam->arg_type_begin(),
+ FunctionProtoParam->getNumArgs(),
+ FunctionProtoArg->arg_type_begin(),
+ FunctionProtoArg->getNumArgs(),
+ Info, Deduced, 0);
}
case Type::InjectedClassName: {
@@ -1045,35 +1248,6 @@ static bool hasTemplateArgumentForDeduction(const TemplateArgument *&Args,
return ArgIdx < NumArgs;
}
-/// \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());
-
- NamedDecl *ND = UPP.first.get<NamedDecl *>();
- 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 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 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,
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