//===------- SemaTemplateInstantiate.cpp - C++ Template Instantiation ------===/ // // 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 instantiation. // //===----------------------------------------------------------------------===/ #include "clang/Sema/SemaInternal.h" #include "TreeTransform.h" #include "clang/AST/ASTConsumer.h" #include "clang/AST/ASTContext.h" #include "clang/AST/ASTLambda.h" #include "clang/AST/DeclTemplate.h" #include "clang/AST/Expr.h" #include "clang/Basic/LangOptions.h" #include "clang/Sema/DeclSpec.h" #include "clang/Sema/Initialization.h" #include "clang/Sema/Lookup.h" #include "clang/Sema/Template.h" #include "clang/Sema/TemplateDeduction.h" using namespace clang; using namespace sema; //===----------------------------------------------------------------------===/ // Template Instantiation Support //===----------------------------------------------------------------------===/ /// \brief Retrieve the template argument list(s) that should be used to /// instantiate the definition of the given declaration. /// /// \param D the declaration for which we are computing template instantiation /// arguments. /// /// \param Innermost if non-NULL, the innermost template argument list. /// /// \param RelativeToPrimary true if we should get the template /// arguments relative to the primary template, even when we're /// dealing with a specialization. This is only relevant for function /// template specializations. /// /// \param Pattern If non-NULL, indicates the pattern from which we will be /// instantiating the definition of the given declaration, \p D. This is /// used to determine the proper set of template instantiation arguments for /// friend function template specializations. MultiLevelTemplateArgumentList Sema::getTemplateInstantiationArgs(NamedDecl *D, const TemplateArgumentList *Innermost, bool RelativeToPrimary, const FunctionDecl *Pattern) { // Accumulate the set of template argument lists in this structure. MultiLevelTemplateArgumentList Result; if (Innermost) Result.addOuterTemplateArguments(Innermost); DeclContext *Ctx = dyn_cast(D); if (!Ctx) { Ctx = D->getDeclContext(); // Add template arguments from a variable template instantiation. if (VarTemplateSpecializationDecl *Spec = dyn_cast(D)) { // We're done when we hit an explicit specialization. if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization && !isa(Spec)) return Result; Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs()); // If this variable template specialization was instantiated from a // specialized member that is a variable template, we're done. assert(Spec->getSpecializedTemplate() && "No variable template?"); llvm::PointerUnion Specialized = Spec->getSpecializedTemplateOrPartial(); if (VarTemplatePartialSpecializationDecl *Partial = Specialized.dyn_cast()) { if (Partial->isMemberSpecialization()) return Result; } else { VarTemplateDecl *Tmpl = Specialized.get(); if (Tmpl->isMemberSpecialization()) return Result; } } // If we have a template template parameter with translation unit context, // then we're performing substitution into a default template argument of // this template template parameter before we've constructed the template // that will own this template template parameter. In this case, we // use empty template parameter lists for all of the outer templates // to avoid performing any substitutions. if (Ctx->isTranslationUnit()) { if (TemplateTemplateParmDecl *TTP = dyn_cast(D)) { for (unsigned I = 0, N = TTP->getDepth() + 1; I != N; ++I) Result.addOuterTemplateArguments(None); return Result; } } } while (!Ctx->isFileContext()) { // Add template arguments from a class template instantiation. if (ClassTemplateSpecializationDecl *Spec = dyn_cast(Ctx)) { // We're done when we hit an explicit specialization. if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization && !isa(Spec)) break; Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs()); // If this class template specialization was instantiated from a // specialized member that is a class template, we're done. assert(Spec->getSpecializedTemplate() && "No class template?"); if (Spec->getSpecializedTemplate()->isMemberSpecialization()) break; } // Add template arguments from a function template specialization. else if (FunctionDecl *Function = dyn_cast(Ctx)) { if (!RelativeToPrimary && (Function->getTemplateSpecializationKind() == TSK_ExplicitSpecialization && !Function->getClassScopeSpecializationPattern())) break; if (const TemplateArgumentList *TemplateArgs = Function->getTemplateSpecializationArgs()) { // Add the template arguments for this specialization. Result.addOuterTemplateArguments(TemplateArgs); // If this function was instantiated from a specialized member that is // a function template, we're done. assert(Function->getPrimaryTemplate() && "No function template?"); if (Function->getPrimaryTemplate()->isMemberSpecialization()) break; // If this function is a generic lambda specialization, we are done. if (isGenericLambdaCallOperatorSpecialization(Function)) break; } else if (FunctionTemplateDecl *FunTmpl = Function->getDescribedFunctionTemplate()) { // Add the "injected" template arguments. Result.addOuterTemplateArguments(FunTmpl->getInjectedTemplateArgs()); } // If this is a friend declaration and it declares an entity at // namespace scope, take arguments from its lexical parent // instead of its semantic parent, unless of course the pattern we're // instantiating actually comes from the file's context! if (Function->getFriendObjectKind() && Function->getDeclContext()->isFileContext() && (!Pattern || !Pattern->getLexicalDeclContext()->isFileContext())) { Ctx = Function->getLexicalDeclContext(); RelativeToPrimary = false; continue; } } else if (CXXRecordDecl *Rec = dyn_cast(Ctx)) { if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) { QualType T = ClassTemplate->getInjectedClassNameSpecialization(); const TemplateSpecializationType *TST = cast(Context.getCanonicalType(T)); Result.addOuterTemplateArguments( llvm::makeArrayRef(TST->getArgs(), TST->getNumArgs())); if (ClassTemplate->isMemberSpecialization()) break; } } Ctx = Ctx->getParent(); RelativeToPrimary = false; } return Result; } bool Sema::ActiveTemplateInstantiation::isInstantiationRecord() const { switch (Kind) { case TemplateInstantiation: case ExceptionSpecInstantiation: case DefaultTemplateArgumentInstantiation: case DefaultFunctionArgumentInstantiation: case ExplicitTemplateArgumentSubstitution: case DeducedTemplateArgumentSubstitution: case PriorTemplateArgumentSubstitution: return true; case DefaultTemplateArgumentChecking: return false; } llvm_unreachable("Invalid InstantiationKind!"); } void Sema::InstantiatingTemplate::Initialize( ActiveTemplateInstantiation::InstantiationKind Kind, SourceLocation PointOfInstantiation, SourceRange InstantiationRange, Decl *Entity, NamedDecl *Template, ArrayRef TemplateArgs, sema::TemplateDeductionInfo *DeductionInfo) { SavedInNonInstantiationSFINAEContext = SemaRef.InNonInstantiationSFINAEContext; Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange); if (!Invalid) { ActiveTemplateInstantiation Inst; Inst.Kind = Kind; Inst.PointOfInstantiation = PointOfInstantiation; Inst.Entity = Entity; Inst.Template = Template; Inst.TemplateArgs = TemplateArgs.data(); Inst.NumTemplateArgs = TemplateArgs.size(); Inst.DeductionInfo = DeductionInfo; Inst.InstantiationRange = InstantiationRange; SemaRef.InNonInstantiationSFINAEContext = false; SemaRef.ActiveTemplateInstantiations.push_back(Inst); if (!Inst.isInstantiationRecord()) ++SemaRef.NonInstantiationEntries; } } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, Decl *Entity, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::TemplateInstantiation, PointOfInstantiation, InstantiationRange, Entity); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, FunctionDecl *Entity, ExceptionSpecification, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::ExceptionSpecInstantiation, PointOfInstantiation, InstantiationRange, Entity); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateDecl *Template, ArrayRef TemplateArgs, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation, PointOfInstantiation, InstantiationRange, Template, nullptr, TemplateArgs); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, FunctionTemplateDecl *FunctionTemplate, ArrayRef TemplateArgs, ActiveTemplateInstantiation::InstantiationKind Kind, sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(Kind, PointOfInstantiation, InstantiationRange, FunctionTemplate, nullptr, TemplateArgs, &DeductionInfo); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, ClassTemplatePartialSpecializationDecl *PartialSpec, ArrayRef TemplateArgs, sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution, PointOfInstantiation, InstantiationRange, PartialSpec, nullptr, TemplateArgs, &DeductionInfo); } Sema::InstantiatingTemplate::InstantiatingTemplate( Sema &SemaRef, SourceLocation PointOfInstantiation, VarTemplatePartialSpecializationDecl *PartialSpec, ArrayRef TemplateArgs, sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution, PointOfInstantiation, InstantiationRange, PartialSpec, nullptr, TemplateArgs, &DeductionInfo); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, ParmVarDecl *Param, ArrayRef TemplateArgs, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation, PointOfInstantiation, InstantiationRange, Param, nullptr, TemplateArgs); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template, NonTypeTemplateParmDecl *Param, ArrayRef TemplateArgs, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution, PointOfInstantiation, InstantiationRange, Param, Template, TemplateArgs); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template, TemplateTemplateParmDecl *Param, ArrayRef TemplateArgs, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution, PointOfInstantiation, InstantiationRange, Param, Template, TemplateArgs); } Sema::InstantiatingTemplate:: InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateDecl *Template, NamedDecl *Param, ArrayRef TemplateArgs, SourceRange InstantiationRange) : SemaRef(SemaRef) { Initialize(ActiveTemplateInstantiation::DefaultTemplateArgumentChecking, PointOfInstantiation, InstantiationRange, Param, Template, TemplateArgs); } void Sema::InstantiatingTemplate::Clear() { if (!Invalid) { if (!SemaRef.ActiveTemplateInstantiations.back().isInstantiationRecord()) { assert(SemaRef.NonInstantiationEntries > 0); --SemaRef.NonInstantiationEntries; } SemaRef.InNonInstantiationSFINAEContext = SavedInNonInstantiationSFINAEContext; // Name lookup no longer looks in this template's defining module. assert(SemaRef.ActiveTemplateInstantiations.size() >= SemaRef.ActiveTemplateInstantiationLookupModules.size() && "forgot to remove a lookup module for a template instantiation"); if (SemaRef.ActiveTemplateInstantiations.size() == SemaRef.ActiveTemplateInstantiationLookupModules.size()) { if (Module *M = SemaRef.ActiveTemplateInstantiationLookupModules.back()) SemaRef.LookupModulesCache.erase(M); SemaRef.ActiveTemplateInstantiationLookupModules.pop_back(); } SemaRef.ActiveTemplateInstantiations.pop_back(); Invalid = true; } } bool Sema::InstantiatingTemplate::CheckInstantiationDepth( SourceLocation PointOfInstantiation, SourceRange InstantiationRange) { assert(SemaRef.NonInstantiationEntries <= SemaRef.ActiveTemplateInstantiations.size()); if ((SemaRef.ActiveTemplateInstantiations.size() - SemaRef.NonInstantiationEntries) <= SemaRef.getLangOpts().InstantiationDepth) return false; SemaRef.Diag(PointOfInstantiation, diag::err_template_recursion_depth_exceeded) << SemaRef.getLangOpts().InstantiationDepth << InstantiationRange; SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth) << SemaRef.getLangOpts().InstantiationDepth; return true; } /// \brief Prints the current instantiation stack through a series of /// notes. void Sema::PrintInstantiationStack() { // Determine which template instantiations to skip, if any. unsigned SkipStart = ActiveTemplateInstantiations.size(), SkipEnd = SkipStart; unsigned Limit = Diags.getTemplateBacktraceLimit(); if (Limit && Limit < ActiveTemplateInstantiations.size()) { SkipStart = Limit / 2 + Limit % 2; SkipEnd = ActiveTemplateInstantiations.size() - Limit / 2; } // FIXME: In all of these cases, we need to show the template arguments unsigned InstantiationIdx = 0; for (SmallVectorImpl::reverse_iterator Active = ActiveTemplateInstantiations.rbegin(), ActiveEnd = ActiveTemplateInstantiations.rend(); Active != ActiveEnd; ++Active, ++InstantiationIdx) { // Skip this instantiation? if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) { if (InstantiationIdx == SkipStart) { // Note that we're skipping instantiations. Diags.Report(Active->PointOfInstantiation, diag::note_instantiation_contexts_suppressed) << unsigned(ActiveTemplateInstantiations.size() - Limit); } continue; } switch (Active->Kind) { case ActiveTemplateInstantiation::TemplateInstantiation: { Decl *D = Active->Entity; if (CXXRecordDecl *Record = dyn_cast(D)) { unsigned DiagID = diag::note_template_member_class_here; if (isa(Record)) DiagID = diag::note_template_class_instantiation_here; Diags.Report(Active->PointOfInstantiation, DiagID) << Context.getTypeDeclType(Record) << Active->InstantiationRange; } else if (FunctionDecl *Function = dyn_cast(D)) { unsigned DiagID; if (Function->getPrimaryTemplate()) DiagID = diag::note_function_template_spec_here; else DiagID = diag::note_template_member_function_here; Diags.Report(Active->PointOfInstantiation, DiagID) << Function << Active->InstantiationRange; } else if (VarDecl *VD = dyn_cast(D)) { Diags.Report(Active->PointOfInstantiation, VD->isStaticDataMember()? diag::note_template_static_data_member_def_here : diag::note_template_variable_def_here) << VD << Active->InstantiationRange; } else if (EnumDecl *ED = dyn_cast(D)) { Diags.Report(Active->PointOfInstantiation, diag::note_template_enum_def_here) << ED << Active->InstantiationRange; } else if (FieldDecl *FD = dyn_cast(D)) { Diags.Report(Active->PointOfInstantiation, diag::note_template_nsdmi_here) << FD << Active->InstantiationRange; } else { Diags.Report(Active->PointOfInstantiation, diag::note_template_type_alias_instantiation_here) << cast(D) << Active->InstantiationRange; } break; } case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation: { TemplateDecl *Template = cast(Active->Entity); SmallVector TemplateArgsStr; llvm::raw_svector_ostream OS(TemplateArgsStr); Template->printName(OS); TemplateSpecializationType::PrintTemplateArgumentList(OS, Active->TemplateArgs, Active->NumTemplateArgs, getPrintingPolicy()); Diags.Report(Active->PointOfInstantiation, diag::note_default_arg_instantiation_here) << OS.str() << Active->InstantiationRange; break; } case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution: { FunctionTemplateDecl *FnTmpl = cast(Active->Entity); Diags.Report(Active->PointOfInstantiation, diag::note_explicit_template_arg_substitution_here) << FnTmpl << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(), Active->TemplateArgs, Active->NumTemplateArgs) << Active->InstantiationRange; break; } case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution: if (ClassTemplatePartialSpecializationDecl *PartialSpec = dyn_cast(Active->Entity)) { Diags.Report(Active->PointOfInstantiation, diag::note_partial_spec_deduct_instantiation_here) << Context.getTypeDeclType(PartialSpec) << getTemplateArgumentBindingsText( PartialSpec->getTemplateParameters(), Active->TemplateArgs, Active->NumTemplateArgs) << Active->InstantiationRange; } else { FunctionTemplateDecl *FnTmpl = cast(Active->Entity); Diags.Report(Active->PointOfInstantiation, diag::note_function_template_deduction_instantiation_here) << FnTmpl << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(), Active->TemplateArgs, Active->NumTemplateArgs) << Active->InstantiationRange; } break; case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation: { ParmVarDecl *Param = cast(Active->Entity); FunctionDecl *FD = cast(Param->getDeclContext()); SmallVector TemplateArgsStr; llvm::raw_svector_ostream OS(TemplateArgsStr); FD->printName(OS); TemplateSpecializationType::PrintTemplateArgumentList(OS, Active->TemplateArgs, Active->NumTemplateArgs, getPrintingPolicy()); Diags.Report(Active->PointOfInstantiation, diag::note_default_function_arg_instantiation_here) << OS.str() << Active->InstantiationRange; break; } case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution: { NamedDecl *Parm = cast(Active->Entity); std::string Name; if (!Parm->getName().empty()) Name = std::string(" '") + Parm->getName().str() + "'"; TemplateParameterList *TemplateParams = nullptr; if (TemplateDecl *Template = dyn_cast(Active->Template)) TemplateParams = Template->getTemplateParameters(); else TemplateParams = cast(Active->Template) ->getTemplateParameters(); Diags.Report(Active->PointOfInstantiation, diag::note_prior_template_arg_substitution) << isa(Parm) << Name << getTemplateArgumentBindingsText(TemplateParams, Active->TemplateArgs, Active->NumTemplateArgs) << Active->InstantiationRange; break; } case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking: { TemplateParameterList *TemplateParams = nullptr; if (TemplateDecl *Template = dyn_cast(Active->Template)) TemplateParams = Template->getTemplateParameters(); else TemplateParams = cast(Active->Template) ->getTemplateParameters(); Diags.Report(Active->PointOfInstantiation, diag::note_template_default_arg_checking) << getTemplateArgumentBindingsText(TemplateParams, Active->TemplateArgs, Active->NumTemplateArgs) << Active->InstantiationRange; break; } case ActiveTemplateInstantiation::ExceptionSpecInstantiation: Diags.Report(Active->PointOfInstantiation, diag::note_template_exception_spec_instantiation_here) << cast(Active->Entity) << Active->InstantiationRange; break; } } } Optional Sema::isSFINAEContext() const { if (InNonInstantiationSFINAEContext) return Optional(nullptr); for (SmallVectorImpl::const_reverse_iterator Active = ActiveTemplateInstantiations.rbegin(), ActiveEnd = ActiveTemplateInstantiations.rend(); Active != ActiveEnd; ++Active) { switch(Active->Kind) { case ActiveTemplateInstantiation::TemplateInstantiation: // An instantiation of an alias template may or may not be a SFINAE // context, depending on what else is on the stack. if (isa(Active->Entity)) break; // Fall through. case ActiveTemplateInstantiation::DefaultFunctionArgumentInstantiation: case ActiveTemplateInstantiation::ExceptionSpecInstantiation: // This is a template instantiation, so there is no SFINAE. return None; case ActiveTemplateInstantiation::DefaultTemplateArgumentInstantiation: case ActiveTemplateInstantiation::PriorTemplateArgumentSubstitution: case ActiveTemplateInstantiation::DefaultTemplateArgumentChecking: // A default template argument instantiation and substitution into // template parameters with arguments for prior parameters may or may // not be a SFINAE context; look further up the stack. break; case ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution: case ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution: // We're either substitution explicitly-specified template arguments // or deduced template arguments, so SFINAE applies. assert(Active->DeductionInfo && "Missing deduction info pointer"); return Active->DeductionInfo; } } return None; } /// \brief Retrieve the depth and index of a parameter pack. static std::pair getDepthAndIndex(NamedDecl *ND) { if (TemplateTypeParmDecl *TTP = dyn_cast(ND)) return std::make_pair(TTP->getDepth(), TTP->getIndex()); if (NonTypeTemplateParmDecl *NTTP = dyn_cast(ND)) return std::make_pair(NTTP->getDepth(), NTTP->getIndex()); TemplateTemplateParmDecl *TTP = cast(ND); return std::make_pair(TTP->getDepth(), TTP->getIndex()); } //===----------------------------------------------------------------------===/ // Template Instantiation for Types //===----------------------------------------------------------------------===/ namespace { class TemplateInstantiator : public TreeTransform { const MultiLevelTemplateArgumentList &TemplateArgs; SourceLocation Loc; DeclarationName Entity; public: typedef TreeTransform inherited; TemplateInstantiator(Sema &SemaRef, const MultiLevelTemplateArgumentList &TemplateArgs, SourceLocation Loc, DeclarationName Entity) : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc), Entity(Entity) { } /// \brief Determine whether the given type \p T has already been /// transformed. /// /// For the purposes of template instantiation, a type has already been /// transformed if it is NULL or if it is not dependent. bool AlreadyTransformed(QualType T); /// \brief Returns the location of the entity being instantiated, if known. SourceLocation getBaseLocation() { return Loc; } /// \brief Returns the name of the entity being instantiated, if any. DeclarationName getBaseEntity() { return Entity; } /// \brief Sets the "base" location and entity when that /// information is known based on another transformation. void setBase(SourceLocation Loc, DeclarationName Entity) { this->Loc = Loc; this->Entity = Entity; } bool TryExpandParameterPacks(SourceLocation EllipsisLoc, SourceRange PatternRange, ArrayRef Unexpanded, bool &ShouldExpand, bool &RetainExpansion, Optional &NumExpansions) { return getSema().CheckParameterPacksForExpansion(EllipsisLoc, PatternRange, Unexpanded, TemplateArgs, ShouldExpand, RetainExpansion, NumExpansions); } void ExpandingFunctionParameterPack(ParmVarDecl *Pack) { SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Pack); } TemplateArgument ForgetPartiallySubstitutedPack() { TemplateArgument Result; if (NamedDecl *PartialPack = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){ MultiLevelTemplateArgumentList &TemplateArgs = const_cast(this->TemplateArgs); unsigned Depth, Index; std::tie(Depth, Index) = getDepthAndIndex(PartialPack); if (TemplateArgs.hasTemplateArgument(Depth, Index)) { Result = TemplateArgs(Depth, Index); TemplateArgs.setArgument(Depth, Index, TemplateArgument()); } } return Result; } void RememberPartiallySubstitutedPack(TemplateArgument Arg) { if (Arg.isNull()) return; if (NamedDecl *PartialPack = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){ MultiLevelTemplateArgumentList &TemplateArgs = const_cast(this->TemplateArgs); unsigned Depth, Index; std::tie(Depth, Index) = getDepthAndIndex(PartialPack); TemplateArgs.setArgument(Depth, Index, Arg); } } /// \brief Transform the given declaration by instantiating a reference to /// this declaration. Decl *TransformDecl(SourceLocation Loc, Decl *D); void transformAttrs(Decl *Old, Decl *New) { SemaRef.InstantiateAttrs(TemplateArgs, Old, New); } void transformedLocalDecl(Decl *Old, Decl *New) { SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New); } /// \brief Transform the definition of the given declaration by /// instantiating it. Decl *TransformDefinition(SourceLocation Loc, Decl *D); /// \brief Transform the first qualifier within a scope by instantiating the /// declaration. NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc); /// \brief Rebuild the exception declaration and register the declaration /// as an instantiated local. VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl, TypeSourceInfo *Declarator, SourceLocation StartLoc, SourceLocation NameLoc, IdentifierInfo *Name); /// \brief Rebuild the Objective-C exception declaration and register the /// declaration as an instantiated local. VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl, TypeSourceInfo *TSInfo, QualType T); /// \brief Check for tag mismatches when instantiating an /// elaborated type. QualType RebuildElaboratedType(SourceLocation KeywordLoc, ElaboratedTypeKeyword Keyword, NestedNameSpecifierLoc QualifierLoc, QualType T); TemplateName TransformTemplateName(CXXScopeSpec &SS, TemplateName Name, SourceLocation NameLoc, QualType ObjectType = QualType(), NamedDecl *FirstQualifierInScope = nullptr); const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH); ExprResult TransformPredefinedExpr(PredefinedExpr *E); ExprResult TransformDeclRefExpr(DeclRefExpr *E); ExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E); ExprResult TransformTemplateParmRefExpr(DeclRefExpr *E, NonTypeTemplateParmDecl *D); ExprResult TransformSubstNonTypeTemplateParmPackExpr( SubstNonTypeTemplateParmPackExpr *E); /// \brief Rebuild a DeclRefExpr for a ParmVarDecl reference. ExprResult RebuildParmVarDeclRefExpr(ParmVarDecl *PD, SourceLocation Loc); /// \brief Transform a reference to a function parameter pack. ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E, ParmVarDecl *PD); /// \brief Transform a FunctionParmPackExpr which was built when we couldn't /// expand a function parameter pack reference which refers to an expanded /// pack. ExprResult TransformFunctionParmPackExpr(FunctionParmPackExpr *E); QualType TransformFunctionProtoType(TypeLocBuilder &TLB, FunctionProtoTypeLoc TL) { // Call the base version; it will forward to our overridden version below. return inherited::TransformFunctionProtoType(TLB, TL); } template QualType TransformFunctionProtoType(TypeLocBuilder &TLB, FunctionProtoTypeLoc TL, CXXRecordDecl *ThisContext, unsigned ThisTypeQuals, Fn TransformExceptionSpec); ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm, int indexAdjustment, Optional NumExpansions, bool ExpectParameterPack); /// \brief Transforms a template type parameter type by performing /// substitution of the corresponding template type argument. QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB, TemplateTypeParmTypeLoc TL); /// \brief Transforms an already-substituted template type parameter pack /// into either itself (if we aren't substituting into its pack expansion) /// or the appropriate substituted argument. QualType TransformSubstTemplateTypeParmPackType(TypeLocBuilder &TLB, SubstTemplateTypeParmPackTypeLoc TL); ExprResult TransformCallExpr(CallExpr *CE) { getSema().CallsUndergoingInstantiation.push_back(CE); ExprResult Result = TreeTransform::TransformCallExpr(CE); getSema().CallsUndergoingInstantiation.pop_back(); return Result; } ExprResult TransformLambdaExpr(LambdaExpr *E) { LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true); return TreeTransform::TransformLambdaExpr(E); } ExprResult TransformLambdaScope(LambdaExpr *E, CXXMethodDecl *NewCallOperator, ArrayRef InitCaptureExprsAndTypes) { CXXMethodDecl *const OldCallOperator = E->getCallOperator(); // In the generic lambda case, we set the NewTemplate to be considered // an "instantiation" of the OldTemplate. if (FunctionTemplateDecl *const NewCallOperatorTemplate = NewCallOperator->getDescribedFunctionTemplate()) { FunctionTemplateDecl *const OldCallOperatorTemplate = OldCallOperator->getDescribedFunctionTemplate(); NewCallOperatorTemplate->setInstantiatedFromMemberTemplate( OldCallOperatorTemplate); } else // For a non-generic lambda we set the NewCallOperator to // be an instantiation of the OldCallOperator. NewCallOperator->setInstantiationOfMemberFunction(OldCallOperator, TSK_ImplicitInstantiation); return inherited::TransformLambdaScope(E, NewCallOperator, InitCaptureExprsAndTypes); } TemplateParameterList *TransformTemplateParameterList( TemplateParameterList *OrigTPL) { if (!OrigTPL || !OrigTPL->size()) return OrigTPL; DeclContext *Owner = OrigTPL->getParam(0)->getDeclContext(); TemplateDeclInstantiator DeclInstantiator(getSema(), /* DeclContext *Owner */ Owner, TemplateArgs); return DeclInstantiator.SubstTemplateParams(OrigTPL); } private: ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm, SourceLocation loc, TemplateArgument arg); }; } bool TemplateInstantiator::AlreadyTransformed(QualType T) { if (T.isNull()) return true; if (T->isInstantiationDependentType() || T->isVariablyModifiedType()) return false; getSema().MarkDeclarationsReferencedInType(Loc, T); return true; } static TemplateArgument getPackSubstitutedTemplateArgument(Sema &S, TemplateArgument Arg) { assert(S.ArgumentPackSubstitutionIndex >= 0); assert(S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size()); Arg = Arg.pack_begin()[S.ArgumentPackSubstitutionIndex]; if (Arg.isPackExpansion()) Arg = Arg.getPackExpansionPattern(); return Arg; } Decl *TemplateInstantiator::TransformDecl(SourceLocation Loc, Decl *D) { if (!D) return nullptr; if (TemplateTemplateParmDecl *TTP = dyn_cast(D)) { if (TTP->getDepth() < TemplateArgs.getNumLevels()) { // If the corresponding template argument is NULL or non-existent, it's // because we are performing instantiation from explicitly-specified // template arguments in a function template, but there were some // arguments left unspecified. if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(), TTP->getPosition())) return D; TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition()); if (TTP->isParameterPack()) { assert(Arg.getKind() == TemplateArgument::Pack && "Missing argument pack"); Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); } TemplateName Template = Arg.getAsTemplate(); assert(!Template.isNull() && Template.getAsTemplateDecl() && "Wrong kind of template template argument"); return Template.getAsTemplateDecl(); } // Fall through to find the instantiated declaration for this template // template parameter. } return SemaRef.FindInstantiatedDecl(Loc, cast(D), TemplateArgs); } Decl *TemplateInstantiator::TransformDefinition(SourceLocation Loc, Decl *D) { Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs); if (!Inst) return nullptr; getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst); return Inst; } NamedDecl * TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc) { // If the first part of the nested-name-specifier was a template type // parameter, instantiate that type parameter down to a tag type. if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null(D)) { const TemplateTypeParmType *TTP = cast(getSema().Context.getTypeDeclType(TTPD)); if (TTP->getDepth() < TemplateArgs.getNumLevels()) { // FIXME: This needs testing w/ member access expressions. TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getIndex()); if (TTP->isParameterPack()) { assert(Arg.getKind() == TemplateArgument::Pack && "Missing argument pack"); if (getSema().ArgumentPackSubstitutionIndex == -1) return nullptr; Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); } QualType T = Arg.getAsType(); if (T.isNull()) return cast_or_null(TransformDecl(Loc, D)); if (const TagType *Tag = T->getAs()) return Tag->getDecl(); // The resulting type is not a tag; complain. getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T; return nullptr; } } return cast_or_null(TransformDecl(Loc, D)); } VarDecl * TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl, TypeSourceInfo *Declarator, SourceLocation StartLoc, SourceLocation NameLoc, IdentifierInfo *Name) { VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, Declarator, StartLoc, NameLoc, Name); if (Var) getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var); return Var; } VarDecl *TemplateInstantiator::RebuildObjCExceptionDecl(VarDecl *ExceptionDecl, TypeSourceInfo *TSInfo, QualType T) { VarDecl *Var = inherited::RebuildObjCExceptionDecl(ExceptionDecl, TSInfo, T); if (Var) getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var); return Var; } QualType TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc, ElaboratedTypeKeyword Keyword, NestedNameSpecifierLoc QualifierLoc, QualType T) { if (const TagType *TT = T->getAs()) { TagDecl* TD = TT->getDecl(); SourceLocation TagLocation = KeywordLoc; IdentifierInfo *Id = TD->getIdentifier(); // TODO: should we even warn on struct/class mismatches for this? Seems // like it's likely to produce a lot of spurious errors. if (Id && Keyword != ETK_None && Keyword != ETK_Typename) { TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword); if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false, TagLocation, *Id)) { SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag) << Id << FixItHint::CreateReplacement(SourceRange(TagLocation), TD->getKindName()); SemaRef.Diag(TD->getLocation(), diag::note_previous_use); } } } return TreeTransform::RebuildElaboratedType(KeywordLoc, Keyword, QualifierLoc, T); } TemplateName TemplateInstantiator::TransformTemplateName(CXXScopeSpec &SS, TemplateName Name, SourceLocation NameLoc, QualType ObjectType, NamedDecl *FirstQualifierInScope) { if (TemplateTemplateParmDecl *TTP = dyn_cast_or_null(Name.getAsTemplateDecl())) { if (TTP->getDepth() < TemplateArgs.getNumLevels()) { // If the corresponding template argument is NULL or non-existent, it's // because we are performing instantiation from explicitly-specified // template arguments in a function template, but there were some // arguments left unspecified. if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(), TTP->getPosition())) return Name; TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition()); if (TTP->isParameterPack()) { assert(Arg.getKind() == TemplateArgument::Pack && "Missing argument pack"); if (getSema().ArgumentPackSubstitutionIndex == -1) { // We have the template argument pack to substitute, but we're not // actually expanding the enclosing pack expansion yet. So, just // keep the entire argument pack. return getSema().Context.getSubstTemplateTemplateParmPack(TTP, Arg); } Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); } TemplateName Template = Arg.getAsTemplate(); assert(!Template.isNull() && "Null template template argument"); // We don't ever want to substitute for a qualified template name, since // the qualifier is handled separately. So, look through the qualified // template name to its underlying declaration. if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName()) Template = TemplateName(QTN->getTemplateDecl()); Template = getSema().Context.getSubstTemplateTemplateParm(TTP, Template); return Template; } } if (SubstTemplateTemplateParmPackStorage *SubstPack = Name.getAsSubstTemplateTemplateParmPack()) { if (getSema().ArgumentPackSubstitutionIndex == -1) return Name; TemplateArgument Arg = SubstPack->getArgumentPack(); Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); return Arg.getAsTemplate(); } return inherited::TransformTemplateName(SS, Name, NameLoc, ObjectType, FirstQualifierInScope); } ExprResult TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) { if (!E->isTypeDependent()) return E; return getSema().BuildPredefinedExpr(E->getLocation(), E->getIdentType()); } ExprResult TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E, NonTypeTemplateParmDecl *NTTP) { // If the corresponding template argument is NULL or non-existent, it's // because we are performing instantiation from explicitly-specified // template arguments in a function template, but there were some // arguments left unspecified. if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(), NTTP->getPosition())) return E; TemplateArgument Arg = TemplateArgs(NTTP->getDepth(), NTTP->getPosition()); if (NTTP->isParameterPack()) { assert(Arg.getKind() == TemplateArgument::Pack && "Missing argument pack"); if (getSema().ArgumentPackSubstitutionIndex == -1) { // We have an argument pack, but we can't select a particular argument // out of it yet. Therefore, we'll build an expression to hold on to that // argument pack. QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs, E->getLocation(), NTTP->getDeclName()); if (TargetType.isNull()) return ExprError(); return new (SemaRef.Context) SubstNonTypeTemplateParmPackExpr(TargetType, NTTP, E->getLocation(), Arg); } Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); } return transformNonTypeTemplateParmRef(NTTP, E->getLocation(), Arg); } const LoopHintAttr * TemplateInstantiator::TransformLoopHintAttr(const LoopHintAttr *LH) { Expr *TransformedExpr = getDerived().TransformExpr(LH->getValue()).get(); if (TransformedExpr == LH->getValue()) return LH; // Generate error if there is a problem with the value. if (getSema().CheckLoopHintExpr(TransformedExpr, LH->getLocation())) return LH; // Create new LoopHintValueAttr with integral expression in place of the // non-type template parameter. return LoopHintAttr::CreateImplicit( getSema().Context, LH->getSemanticSpelling(), LH->getOption(), LH->getState(), TransformedExpr, LH->getRange()); } ExprResult TemplateInstantiator::transformNonTypeTemplateParmRef( NonTypeTemplateParmDecl *parm, SourceLocation loc, TemplateArgument arg) { ExprResult result; QualType type; // The template argument itself might be an expression, in which // case we just return that expression. if (arg.getKind() == TemplateArgument::Expression) { Expr *argExpr = arg.getAsExpr(); result = argExpr; type = argExpr->getType(); } else if (arg.getKind() == TemplateArgument::Declaration || arg.getKind() == TemplateArgument::NullPtr) { ValueDecl *VD; if (arg.getKind() == TemplateArgument::Declaration) { VD = cast(arg.getAsDecl()); // Find the instantiation of the template argument. This is // required for nested templates. VD = cast_or_null( getSema().FindInstantiatedDecl(loc, VD, TemplateArgs)); if (!VD) return ExprError(); } else { // Propagate NULL template argument. VD = nullptr; } // Derive the type we want the substituted decl to have. This had // better be non-dependent, or these checks will have serious problems. if (parm->isExpandedParameterPack()) { type = parm->getExpansionType(SemaRef.ArgumentPackSubstitutionIndex); } else if (parm->isParameterPack() && isa(parm->getType())) { type = SemaRef.SubstType( cast(parm->getType())->getPattern(), TemplateArgs, loc, parm->getDeclName()); } else { type = SemaRef.SubstType(parm->getType(), TemplateArgs, loc, parm->getDeclName()); } assert(!type.isNull() && "type substitution failed for param type"); assert(!type->isDependentType() && "param type still dependent"); result = SemaRef.BuildExpressionFromDeclTemplateArgument(arg, type, loc); if (!result.isInvalid()) type = result.get()->getType(); } else { result = SemaRef.BuildExpressionFromIntegralTemplateArgument(arg, loc); // Note that this type can be different from the type of 'result', // e.g. if it's an enum type. type = arg.getIntegralType(); } if (result.isInvalid()) return ExprError(); Expr *resultExpr = result.get(); return new (SemaRef.Context) SubstNonTypeTemplateParmExpr( type, resultExpr->getValueKind(), loc, parm, resultExpr); } ExprResult TemplateInstantiator::TransformSubstNonTypeTemplateParmPackExpr( SubstNonTypeTemplateParmPackExpr *E) { if (getSema().ArgumentPackSubstitutionIndex == -1) { // We aren't expanding the parameter pack, so just return ourselves. return E; } TemplateArgument Arg = E->getArgumentPack(); Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); return transformNonTypeTemplateParmRef(E->getParameterPack(), E->getParameterPackLocation(), Arg); } ExprResult TemplateInstantiator::RebuildParmVarDeclRefExpr(ParmVarDecl *PD, SourceLocation Loc) { DeclarationNameInfo NameInfo(PD->getDeclName(), Loc); return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD); } ExprResult TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) { if (getSema().ArgumentPackSubstitutionIndex != -1) { // We can expand this parameter pack now. ParmVarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex); ValueDecl *VD = cast_or_null(TransformDecl(E->getExprLoc(), D)); if (!VD) return ExprError(); return RebuildParmVarDeclRefExpr(cast(VD), E->getExprLoc()); } QualType T = TransformType(E->getType()); if (T.isNull()) return ExprError(); // Transform each of the parameter expansions into the corresponding // parameters in the instantiation of the function decl. SmallVector Parms; Parms.reserve(E->getNumExpansions()); for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end(); I != End; ++I) { ParmVarDecl *D = cast_or_null(TransformDecl(E->getExprLoc(), *I)); if (!D) return ExprError(); Parms.push_back(D); } return FunctionParmPackExpr::Create(getSema().Context, T, E->getParameterPack(), E->getParameterPackLocation(), Parms); } ExprResult TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E, ParmVarDecl *PD) { typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack; llvm::PointerUnion *Found = getSema().CurrentInstantiationScope->findInstantiationOf(PD); assert(Found && "no instantiation for parameter pack"); Decl *TransformedDecl; if (DeclArgumentPack *Pack = Found->dyn_cast()) { // If this is a reference to a function parameter pack which we can // substitute but can't yet expand, build a FunctionParmPackExpr for it. if (getSema().ArgumentPackSubstitutionIndex == -1) { QualType T = TransformType(E->getType()); if (T.isNull()) return ExprError(); return FunctionParmPackExpr::Create(getSema().Context, T, PD, E->getExprLoc(), *Pack); } TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex]; } else { TransformedDecl = Found->get(); } // We have either an unexpanded pack or a specific expansion. return RebuildParmVarDeclRefExpr(cast(TransformedDecl), E->getExprLoc()); } ExprResult TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) { NamedDecl *D = E->getDecl(); // Handle references to non-type template parameters and non-type template // parameter packs. if (NonTypeTemplateParmDecl *NTTP = dyn_cast(D)) { if (NTTP->getDepth() < TemplateArgs.getNumLevels()) return TransformTemplateParmRefExpr(E, NTTP); // We have a non-type template parameter that isn't fully substituted; // FindInstantiatedDecl will find it in the local instantiation scope. } // Handle references to function parameter packs. if (ParmVarDecl *PD = dyn_cast(D)) if (PD->isParameterPack()) return TransformFunctionParmPackRefExpr(E, PD); return TreeTransform::TransformDeclRefExpr(E); } ExprResult TemplateInstantiator::TransformCXXDefaultArgExpr( CXXDefaultArgExpr *E) { assert(!cast(E->getParam()->getDeclContext())-> getDescribedFunctionTemplate() && "Default arg expressions are never formed in dependent cases."); return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(), cast(E->getParam()->getDeclContext()), E->getParam()); } template QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB, FunctionProtoTypeLoc TL, CXXRecordDecl *ThisContext, unsigned ThisTypeQuals, Fn TransformExceptionSpec) { // We need a local instantiation scope for this function prototype. LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true); return inherited::TransformFunctionProtoType( TLB, TL, ThisContext, ThisTypeQuals, TransformExceptionSpec); } ParmVarDecl * TemplateInstantiator::TransformFunctionTypeParam(ParmVarDecl *OldParm, int indexAdjustment, Optional NumExpansions, bool ExpectParameterPack) { return SemaRef.SubstParmVarDecl(OldParm, TemplateArgs, indexAdjustment, NumExpansions, ExpectParameterPack); } QualType TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB, TemplateTypeParmTypeLoc TL) { const TemplateTypeParmType *T = TL.getTypePtr(); if (T->getDepth() < TemplateArgs.getNumLevels()) { // Replace the template type parameter with its corresponding // template argument. // If the corresponding template argument is NULL or doesn't exist, it's // because we are performing instantiation from explicitly-specified // template arguments in a function template class, but there were some // arguments left unspecified. if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) { TemplateTypeParmTypeLoc NewTL = TLB.push(TL.getType()); NewTL.setNameLoc(TL.getNameLoc()); return TL.getType(); } TemplateArgument Arg = TemplateArgs(T->getDepth(), T->getIndex()); if (T->isParameterPack()) { assert(Arg.getKind() == TemplateArgument::Pack && "Missing argument pack"); if (getSema().ArgumentPackSubstitutionIndex == -1) { // We have the template argument pack, but we're not expanding the // enclosing pack expansion yet. Just save the template argument // pack for later substitution. QualType Result = getSema().Context.getSubstTemplateTypeParmPackType(T, Arg); SubstTemplateTypeParmPackTypeLoc NewTL = TLB.push(Result); NewTL.setNameLoc(TL.getNameLoc()); return Result; } Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); } assert(Arg.getKind() == TemplateArgument::Type && "Template argument kind mismatch"); QualType Replacement = Arg.getAsType(); // TODO: only do this uniquing once, at the start of instantiation. QualType Result = getSema().Context.getSubstTemplateTypeParmType(T, Replacement); SubstTemplateTypeParmTypeLoc NewTL = TLB.push(Result); NewTL.setNameLoc(TL.getNameLoc()); return Result; } // The template type parameter comes from an inner template (e.g., // the template parameter list of a member template inside the // template we are instantiating). Create a new template type // parameter with the template "level" reduced by one. TemplateTypeParmDecl *NewTTPDecl = nullptr; if (TemplateTypeParmDecl *OldTTPDecl = T->getDecl()) NewTTPDecl = cast_or_null( TransformDecl(TL.getNameLoc(), OldTTPDecl)); QualType Result = getSema().Context.getTemplateTypeParmType(T->getDepth() - TemplateArgs.getNumLevels(), T->getIndex(), T->isParameterPack(), NewTTPDecl); TemplateTypeParmTypeLoc NewTL = TLB.push(Result); NewTL.setNameLoc(TL.getNameLoc()); return Result; } QualType TemplateInstantiator::TransformSubstTemplateTypeParmPackType( TypeLocBuilder &TLB, SubstTemplateTypeParmPackTypeLoc TL) { if (getSema().ArgumentPackSubstitutionIndex == -1) { // We aren't expanding the parameter pack, so just return ourselves. SubstTemplateTypeParmPackTypeLoc NewTL = TLB.push(TL.getType()); NewTL.setNameLoc(TL.getNameLoc()); return TL.getType(); } TemplateArgument Arg = TL.getTypePtr()->getArgumentPack(); Arg = getPackSubstitutedTemplateArgument(getSema(), Arg); QualType Result = Arg.getAsType(); Result = getSema().Context.getSubstTemplateTypeParmType( TL.getTypePtr()->getReplacedParameter(), Result); SubstTemplateTypeParmTypeLoc NewTL = TLB.push(Result); NewTL.setNameLoc(TL.getNameLoc()); return Result; } /// \brief Perform substitution on the type T with a given set of template /// arguments. /// /// This routine substitutes the given template arguments into the /// type T and produces the instantiated type. /// /// \param T the type into which the template arguments will be /// substituted. If this type is not dependent, it will be returned /// immediately. /// /// \param Args the template arguments that will be /// substituted for the top-level template parameters within T. /// /// \param Loc the location in the source code where this substitution /// is being performed. It will typically be the location of the /// declarator (if we're instantiating the type of some declaration) /// or the location of the type in the source code (if, e.g., we're /// instantiating the type of a cast expression). /// /// \param Entity the name of the entity associated with a declaration /// being instantiated (if any). May be empty to indicate that there /// is no such entity (if, e.g., this is a type that occurs as part of /// a cast expression) or that the entity has no name (e.g., an /// unnamed function parameter). /// /// \returns If the instantiation succeeds, the instantiated /// type. Otherwise, produces diagnostics and returns a NULL type. TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T, const MultiLevelTemplateArgumentList &Args, SourceLocation Loc, DeclarationName Entity) { assert(!ActiveTemplateInstantiations.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"); if (!T->getType()->isInstantiationDependentType() && !T->getType()->isVariablyModifiedType()) return T; TemplateInstantiator Instantiator(*this, Args, Loc, Entity); return Instantiator.TransformType(T); } TypeSourceInfo *Sema::SubstType(TypeLoc TL, const MultiLevelTemplateArgumentList &Args, SourceLocation Loc, DeclarationName Entity) { assert(!ActiveTemplateInstantiations.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"); if (TL.getType().isNull()) return nullptr; if (!TL.getType()->isInstantiationDependentType() && !TL.getType()->isVariablyModifiedType()) { // FIXME: Make a copy of the TypeLoc data here, so that we can // return a new TypeSourceInfo. Inefficient! TypeLocBuilder TLB; TLB.pushFullCopy(TL); return TLB.getTypeSourceInfo(Context, TL.getType()); } TemplateInstantiator Instantiator(*this, Args, Loc, Entity); TypeLocBuilder TLB; TLB.reserve(TL.getFullDataSize()); QualType Result = Instantiator.TransformType(TLB, TL); if (Result.isNull()) return nullptr; return TLB.getTypeSourceInfo(Context, Result); } /// Deprecated form of the above. QualType Sema::SubstType(QualType T, const MultiLevelTemplateArgumentList &TemplateArgs, SourceLocation Loc, DeclarationName Entity) { assert(!ActiveTemplateInstantiations.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"); // If T is not a dependent type or a variably-modified type, there // is nothing to do. if (!T->isInstantiationDependentType() && !T->isVariablyModifiedType()) return T; TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity); return Instantiator.TransformType(T); } static bool NeedsInstantiationAsFunctionType(TypeSourceInfo *T) { if (T->getType()->isInstantiationDependentType() || T->getType()->isVariablyModifiedType()) return true; TypeLoc TL = T->getTypeLoc().IgnoreParens(); if (!TL.getAs()) return false; FunctionProtoTypeLoc FP = TL.castAs(); for (unsigned I = 0, E = FP.getNumParams(); I != E; ++I) { ParmVarDecl *P = FP.getParam(I); // This must be synthesized from a typedef. if (!P) continue; // The parameter's type as written might be dependent even if the // decayed type was not dependent. if (TypeSourceInfo *TSInfo = P->getTypeSourceInfo()) if (TSInfo->getType()->isInstantiationDependentType()) return true; // TODO: currently we always rebuild expressions. When we // properly get lazier about this, we should use the same // logic to avoid rebuilding prototypes here. if (P->hasDefaultArg()) return true; } return false; } /// A form of SubstType intended specifically for instantiating the /// type of a FunctionDecl. Its purpose is solely to force the /// instantiation of default-argument expressions and to avoid /// instantiating an exception-specification. TypeSourceInfo *Sema::SubstFunctionDeclType(TypeSourceInfo *T, const MultiLevelTemplateArgumentList &Args, SourceLocation Loc, DeclarationName Entity, CXXRecordDecl *ThisContext, unsigned ThisTypeQuals) { assert(!ActiveTemplateInstantiations.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"); if (!NeedsInstantiationAsFunctionType(T)) return T; TemplateInstantiator Instantiator(*this, Args, Loc, Entity); TypeLocBuilder TLB; TypeLoc TL = T->getTypeLoc(); TLB.reserve(TL.getFullDataSize()); QualType Result; if (FunctionProtoTypeLoc Proto = TL.IgnoreParens().getAs()) { // Instantiate the type, other than its exception specification. The // exception specification is instantiated in InitFunctionInstantiation // once we've built the FunctionDecl. // FIXME: Set the exception specification to EST_Uninstantiated here, // instead of rebuilding the function type again later. Result = Instantiator.TransformFunctionProtoType( TLB, Proto, ThisContext, ThisTypeQuals, [](FunctionProtoType::ExceptionSpecInfo &ESI, bool &Changed) { return false; }); } else { Result = Instantiator.TransformType(TLB, TL); } if (Result.isNull()) return nullptr; return TLB.getTypeSourceInfo(Context, Result); } void Sema::SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto, const MultiLevelTemplateArgumentList &Args) { FunctionProtoType::ExceptionSpecInfo ESI = Proto->getExtProtoInfo().ExceptionSpec; assert(ESI.Type != EST_Uninstantiated); TemplateInstantiator Instantiator(*this, Args, New->getLocation(), New->getDeclName()); SmallVector ExceptionStorage; bool Changed = false; if (Instantiator.TransformExceptionSpec( New->getTypeSourceInfo()->getTypeLoc().getLocEnd(), ESI, ExceptionStorage, Changed)) // On error, recover by dropping the exception specification. ESI.Type = EST_None; UpdateExceptionSpec(New, ESI); } ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm, const MultiLevelTemplateArgumentList &TemplateArgs, int indexAdjustment, Optional NumExpansions, bool ExpectParameterPack) { TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo(); TypeSourceInfo *NewDI = nullptr; TypeLoc OldTL = OldDI->getTypeLoc(); if (PackExpansionTypeLoc ExpansionTL = OldTL.getAs()) { // We have a function parameter pack. Substitute into the pattern of the // expansion. NewDI = SubstType(ExpansionTL.getPatternLoc(), TemplateArgs, OldParm->getLocation(), OldParm->getDeclName()); if (!NewDI) return nullptr; if (NewDI->getType()->containsUnexpandedParameterPack()) { // We still have unexpanded parameter packs, which means that // our function parameter is still a function parameter pack. // Therefore, make its type a pack expansion type. NewDI = CheckPackExpansion(NewDI, ExpansionTL.getEllipsisLoc(), NumExpansions); } else if (ExpectParameterPack) { // We expected to get a parameter pack but didn't (because the type // itself is not a pack expansion type), so complain. This can occur when // the substitution goes through an alias template that "loses" the // pack expansion. Diag(OldParm->getLocation(), diag::err_function_parameter_pack_without_parameter_packs) << NewDI->getType(); return nullptr; } } else { NewDI = SubstType(OldDI, TemplateArgs, OldParm->getLocation(), OldParm->getDeclName()); } if (!NewDI) return nullptr; if (NewDI->getType()->isVoidType()) { Diag(OldParm->getLocation(), diag::err_param_with_void_type); return nullptr; } ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(), OldParm->getInnerLocStart(), OldParm->getLocation(), OldParm->getIdentifier(), NewDI->getType(), NewDI, OldParm->getStorageClass()); if (!NewParm) return nullptr; // Mark the (new) default argument as uninstantiated (if any). if (OldParm->hasUninstantiatedDefaultArg()) { Expr *Arg = OldParm->getUninstantiatedDefaultArg(); NewParm->setUninstantiatedDefaultArg(Arg); } else if (OldParm->hasUnparsedDefaultArg()) { NewParm->setUnparsedDefaultArg(); UnparsedDefaultArgInstantiations[OldParm].push_back(NewParm); } else if (Expr *Arg = OldParm->getDefaultArg()) // FIXME: if we non-lazily instantiated non-dependent default args for // non-dependent parameter types we could remove a bunch of duplicate // conversion warnings for such arguments. NewParm->setUninstantiatedDefaultArg(Arg); NewParm->setHasInheritedDefaultArg(OldParm->hasInheritedDefaultArg()); if (OldParm->isParameterPack() && !NewParm->isParameterPack()) { // Add the new parameter to the instantiated parameter pack. CurrentInstantiationScope->InstantiatedLocalPackArg(OldParm, NewParm); } else { // Introduce an Old -> New mapping CurrentInstantiationScope->InstantiatedLocal(OldParm, NewParm); } // FIXME: OldParm may come from a FunctionProtoType, in which case CurContext // can be anything, is this right ? NewParm->setDeclContext(CurContext); NewParm->setScopeInfo(OldParm->getFunctionScopeDepth(), OldParm->getFunctionScopeIndex() + indexAdjustment); InstantiateAttrs(TemplateArgs, OldParm, NewParm); return NewParm; } /// \brief Substitute the given template arguments into the given set of /// parameters, producing the set of parameter types that would be generated /// from such a substitution. bool Sema::SubstParmTypes(SourceLocation Loc, ParmVarDecl **Params, unsigned NumParams, const MultiLevelTemplateArgumentList &TemplateArgs, SmallVectorImpl &ParamTypes, SmallVectorImpl *OutParams) { assert(!ActiveTemplateInstantiations.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"); TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, DeclarationName()); return Instantiator.TransformFunctionTypeParams(Loc, Params, NumParams, nullptr, ParamTypes, OutParams); } /// \brief Perform substitution on the base class specifiers of the /// given class template specialization. /// /// Produces a diagnostic and returns true on error, returns false and /// attaches the instantiated base classes to the class template /// specialization if successful. bool Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs) { bool Invalid = false; SmallVector InstantiatedBases; for (const auto Base : Pattern->bases()) { if (!Base.getType()->isDependentType()) { if (const CXXRecordDecl *RD = Base.getType()->getAsCXXRecordDecl()) { if (RD->isInvalidDecl()) Instantiation->setInvalidDecl(); } InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(Base)); continue; } SourceLocation EllipsisLoc; TypeSourceInfo *BaseTypeLoc; if (Base.isPackExpansion()) { // This is a pack expansion. See whether we should expand it now, or // wait until later. SmallVector Unexpanded; collectUnexpandedParameterPacks(Base.getTypeSourceInfo()->getTypeLoc(), Unexpanded); bool ShouldExpand = false; bool RetainExpansion = false; Optional NumExpansions; if (CheckParameterPacksForExpansion(Base.getEllipsisLoc(), Base.getSourceRange(), Unexpanded, TemplateArgs, ShouldExpand, RetainExpansion, NumExpansions)) { Invalid = true; continue; } // If we should expand this pack expansion now, do so. if (ShouldExpand) { for (unsigned I = 0; I != *NumExpansions; ++I) { Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I); TypeSourceInfo *BaseTypeLoc = SubstType(Base.getTypeSourceInfo(), TemplateArgs, Base.getSourceRange().getBegin(), DeclarationName()); if (!BaseTypeLoc) { Invalid = true; continue; } if (CXXBaseSpecifier *InstantiatedBase = CheckBaseSpecifier(Instantiation, Base.getSourceRange(), Base.isVirtual(), Base.getAccessSpecifierAsWritten(), BaseTypeLoc, SourceLocation())) InstantiatedBases.push_back(InstantiatedBase); else Invalid = true; } continue; } // The resulting base specifier will (still) be a pack expansion. EllipsisLoc = Base.getEllipsisLoc(); Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1); BaseTypeLoc = SubstType(Base.getTypeSourceInfo(), TemplateArgs, Base.getSourceRange().getBegin(), DeclarationName()); } else { BaseTypeLoc = SubstType(Base.getTypeSourceInfo(), TemplateArgs, Base.getSourceRange().getBegin(), DeclarationName()); } if (!BaseTypeLoc) { Invalid = true; continue; } if (CXXBaseSpecifier *InstantiatedBase = CheckBaseSpecifier(Instantiation, Base.getSourceRange(), Base.isVirtual(), Base.getAccessSpecifierAsWritten(), BaseTypeLoc, EllipsisLoc)) InstantiatedBases.push_back(InstantiatedBase); else Invalid = true; } if (!Invalid && AttachBaseSpecifiers(Instantiation, InstantiatedBases.data(), InstantiatedBases.size())) Invalid = true; return Invalid; } // Defined via #include from SemaTemplateInstantiateDecl.cpp namespace clang { namespace sema { Attr *instantiateTemplateAttribute(const Attr *At, ASTContext &C, Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs); } } /// Determine whether we would be unable to instantiate this template (because /// it either has no definition, or is in the process of being instantiated). static bool DiagnoseUninstantiableTemplate(Sema &S, SourceLocation PointOfInstantiation, TagDecl *Instantiation, bool InstantiatedFromMember, TagDecl *Pattern, TagDecl *PatternDef, TemplateSpecializationKind TSK, bool Complain = true) { if (PatternDef && !PatternDef->isBeingDefined()) return false; if (!Complain || (PatternDef && PatternDef->isInvalidDecl())) { // Say nothing } else if (PatternDef) { assert(PatternDef->isBeingDefined()); S.Diag(PointOfInstantiation, diag::err_template_instantiate_within_definition) << (TSK != TSK_ImplicitInstantiation) << S.Context.getTypeDeclType(Instantiation); // Not much point in noting the template declaration here, since // we're lexically inside it. Instantiation->setInvalidDecl(); } else if (InstantiatedFromMember) { S.Diag(PointOfInstantiation, diag::err_implicit_instantiate_member_undefined) << S.Context.getTypeDeclType(Instantiation); S.Diag(Pattern->getLocation(), diag::note_member_declared_at); } else { S.Diag(PointOfInstantiation, diag::err_template_instantiate_undefined) << (TSK != TSK_ImplicitInstantiation) << S.Context.getTypeDeclType(Instantiation); S.Diag(Pattern->getLocation(), diag::note_template_decl_here); } // In general, Instantiation isn't marked invalid to get more than one // error for multiple undefined instantiations. But the code that does // explicit declaration -> explicit definition conversion can't handle // invalid declarations, so mark as invalid in that case. if (TSK == TSK_ExplicitInstantiationDeclaration) Instantiation->setInvalidDecl(); return true; } /// \brief Instantiate the definition of a class from a given pattern. /// /// \param PointOfInstantiation The point of instantiation within the /// source code. /// /// \param Instantiation is the declaration whose definition is being /// instantiated. This will be either a class template specialization /// or a member class of a class template specialization. /// /// \param Pattern is the pattern from which the instantiation /// occurs. This will be either the declaration of a class template or /// the declaration of a member class of a class template. /// /// \param TemplateArgs The template arguments to be substituted into /// the pattern. /// /// \param TSK the kind of implicit or explicit instantiation to perform. /// /// \param Complain whether to complain if the class cannot be instantiated due /// to the lack of a definition. /// /// \returns true if an error occurred, false otherwise. bool Sema::InstantiateClass(SourceLocation PointOfInstantiation, CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs, TemplateSpecializationKind TSK, bool Complain) { CXXRecordDecl *PatternDef = cast_or_null(Pattern->getDefinition()); if (DiagnoseUninstantiableTemplate(*this, PointOfInstantiation, Instantiation, Instantiation->getInstantiatedFromMemberClass(), Pattern, PatternDef, TSK, Complain)) return true; Pattern = PatternDef; // \brief Record the point of instantiation. if (MemberSpecializationInfo *MSInfo = Instantiation->getMemberSpecializationInfo()) { MSInfo->setTemplateSpecializationKind(TSK); MSInfo->setPointOfInstantiation(PointOfInstantiation); } else if (ClassTemplateSpecializationDecl *Spec = dyn_cast(Instantiation)) { Spec->setTemplateSpecializationKind(TSK); Spec->setPointOfInstantiation(PointOfInstantiation); } InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); if (Inst.isInvalid()) return true; // Enter the scope of this instantiation. We don't use // PushDeclContext because we don't have a scope. ContextRAII SavedContext(*this, Instantiation); EnterExpressionEvaluationContext EvalContext(*this, Sema::PotentiallyEvaluated); // If this is an instantiation of a local class, merge this local // instantiation scope with the enclosing scope. Otherwise, every // instantiation of a class has its own local instantiation scope. bool MergeWithParentScope = !Instantiation->isDefinedOutsideFunctionOrMethod(); LocalInstantiationScope Scope(*this, MergeWithParentScope); // Pull attributes from the pattern onto the instantiation. InstantiateAttrs(TemplateArgs, Pattern, Instantiation); // Start the definition of this instantiation. Instantiation->startDefinition(); // The instantiation is visible here, even if it was first declared in an // unimported module. Instantiation->setHidden(false); // FIXME: This loses the as-written tag kind for an explicit instantiation. Instantiation->setTagKind(Pattern->getTagKind()); // Do substitution on the base class specifiers. if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs)) Instantiation->setInvalidDecl(); TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); SmallVector Fields; // Delay instantiation of late parsed attributes. LateInstantiatedAttrVec LateAttrs; Instantiator.enableLateAttributeInstantiation(&LateAttrs); for (auto *Member : Pattern->decls()) { // Don't instantiate members not belonging in this semantic context. // e.g. for: // @code // template class A { // class B *g; // }; // @endcode // 'class B' has the template as lexical context but semantically it is // introduced in namespace scope. if (Member->getDeclContext() != Pattern) continue; if (Member->isInvalidDecl()) { Instantiation->setInvalidDecl(); continue; } Decl *NewMember = Instantiator.Visit(Member); if (NewMember) { if (FieldDecl *Field = dyn_cast(NewMember)) { Fields.push_back(Field); } else if (EnumDecl *Enum = dyn_cast(NewMember)) { // C++11 [temp.inst]p1: The implicit instantiation of a class template // specialization causes the implicit instantiation of the definitions // of unscoped member enumerations. // Record a point of instantiation for this implicit instantiation. if (TSK == TSK_ImplicitInstantiation && !Enum->isScoped() && Enum->isCompleteDefinition()) { MemberSpecializationInfo *MSInfo =Enum->getMemberSpecializationInfo(); assert(MSInfo && "no spec info for member enum specialization"); MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation); MSInfo->setPointOfInstantiation(PointOfInstantiation); } } else if (StaticAssertDecl *SA = dyn_cast(NewMember)) { if (SA->isFailed()) { // A static_assert failed. Bail out; instantiating this // class is probably not meaningful. Instantiation->setInvalidDecl(); break; } } if (NewMember->isInvalidDecl()) Instantiation->setInvalidDecl(); } else { // FIXME: Eventually, a NULL return will mean that one of the // instantiations was a semantic disaster, and we'll want to mark the // declaration invalid. // For now, we expect to skip some members that we can't yet handle. } } // Finish checking fields. ActOnFields(nullptr, Instantiation->getLocation(), Instantiation, Fields, SourceLocation(), SourceLocation(), nullptr); CheckCompletedCXXClass(Instantiation); // Instantiate late parsed attributes, and attach them to their decls. // See Sema::InstantiateAttrs for (LateInstantiatedAttrVec::iterator I = LateAttrs.begin(), E = LateAttrs.end(); I != E; ++I) { assert(CurrentInstantiationScope == Instantiator.getStartingScope()); CurrentInstantiationScope = I->Scope; // Allow 'this' within late-parsed attributes. NamedDecl *ND = dyn_cast(I->NewDecl); CXXRecordDecl *ThisContext = dyn_cast_or_null(ND->getDeclContext()); CXXThisScopeRAII ThisScope(*this, ThisContext, /*TypeQuals*/0, ND && ND->isCXXInstanceMember()); Attr *NewAttr = instantiateTemplateAttribute(I->TmplAttr, Context, *this, TemplateArgs); I->NewDecl->addAttr(NewAttr); LocalInstantiationScope::deleteScopes(I->Scope, Instantiator.getStartingScope()); } Instantiator.disableLateAttributeInstantiation(); LateAttrs.clear(); ActOnFinishDelayedMemberInitializers(Instantiation); // FIXME: We should do something similar for explicit instantiations so they // end up in the right module. if (TSK == TSK_ImplicitInstantiation) { Instantiation->setLocation(Pattern->getLocation()); Instantiation->setLocStart(Pattern->getInnerLocStart()); Instantiation->setRBraceLoc(Pattern->getRBraceLoc()); } if (!Instantiation->isInvalidDecl()) { // Perform any dependent diagnostics from the pattern. PerformDependentDiagnostics(Pattern, TemplateArgs); // Instantiate any out-of-line class template partial // specializations now. for (TemplateDeclInstantiator::delayed_partial_spec_iterator P = Instantiator.delayed_partial_spec_begin(), PEnd = Instantiator.delayed_partial_spec_end(); P != PEnd; ++P) { if (!Instantiator.InstantiateClassTemplatePartialSpecialization( P->first, P->second)) { Instantiation->setInvalidDecl(); break; } } // Instantiate any out-of-line variable template partial // specializations now. for (TemplateDeclInstantiator::delayed_var_partial_spec_iterator P = Instantiator.delayed_var_partial_spec_begin(), PEnd = Instantiator.delayed_var_partial_spec_end(); P != PEnd; ++P) { if (!Instantiator.InstantiateVarTemplatePartialSpecialization( P->first, P->second)) { Instantiation->setInvalidDecl(); break; } } } // Exit the scope of this instantiation. SavedContext.pop(); if (!Instantiation->isInvalidDecl()) { Consumer.HandleTagDeclDefinition(Instantiation); // Always emit the vtable for an explicit instantiation definition // of a polymorphic class template specialization. if (TSK == TSK_ExplicitInstantiationDefinition) MarkVTableUsed(PointOfInstantiation, Instantiation, true); } return Instantiation->isInvalidDecl(); } /// \brief Instantiate the definition of an enum from a given pattern. /// /// \param PointOfInstantiation The point of instantiation within the /// source code. /// \param Instantiation is the declaration whose definition is being /// instantiated. This will be a member enumeration of a class /// temploid specialization, or a local enumeration within a /// function temploid specialization. /// \param Pattern The templated declaration from which the instantiation /// occurs. /// \param TemplateArgs The template arguments to be substituted into /// the pattern. /// \param TSK The kind of implicit or explicit instantiation to perform. /// /// \return \c true if an error occurred, \c false otherwise. bool Sema::InstantiateEnum(SourceLocation PointOfInstantiation, EnumDecl *Instantiation, EnumDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs, TemplateSpecializationKind TSK) { EnumDecl *PatternDef = Pattern->getDefinition(); if (DiagnoseUninstantiableTemplate(*this, PointOfInstantiation, Instantiation, Instantiation->getInstantiatedFromMemberEnum(), Pattern, PatternDef, TSK,/*Complain*/true)) return true; Pattern = PatternDef; // Record the point of instantiation. if (MemberSpecializationInfo *MSInfo = Instantiation->getMemberSpecializationInfo()) { MSInfo->setTemplateSpecializationKind(TSK); MSInfo->setPointOfInstantiation(PointOfInstantiation); } InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); if (Inst.isInvalid()) return true; // The instantiation is visible here, even if it was first declared in an // unimported module. Instantiation->setHidden(false); // Enter the scope of this instantiation. We don't use // PushDeclContext because we don't have a scope. ContextRAII SavedContext(*this, Instantiation); EnterExpressionEvaluationContext EvalContext(*this, Sema::PotentiallyEvaluated); LocalInstantiationScope Scope(*this, /*MergeWithParentScope*/true); // Pull attributes from the pattern onto the instantiation. InstantiateAttrs(TemplateArgs, Pattern, Instantiation); TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); Instantiator.InstantiateEnumDefinition(Instantiation, Pattern); // Exit the scope of this instantiation. SavedContext.pop(); return Instantiation->isInvalidDecl(); } /// \brief Instantiate the definition of a field from the given pattern. /// /// \param PointOfInstantiation The point of instantiation within the /// source code. /// \param Instantiation is the declaration whose definition is being /// instantiated. This will be a class of a class temploid /// specialization, or a local enumeration within a function temploid /// specialization. /// \param Pattern The templated declaration from which the instantiation /// occurs. /// \param TemplateArgs The template arguments to be substituted into /// the pattern. /// /// \return \c true if an error occurred, \c false otherwise. bool Sema::InstantiateInClassInitializer( SourceLocation PointOfInstantiation, FieldDecl *Instantiation, FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs) { // If there is no initializer, we don't need to do anything. if (!Pattern->hasInClassInitializer()) return false; assert(Instantiation->getInClassInitStyle() == Pattern->getInClassInitStyle() && "pattern and instantiation disagree about init style"); // Error out if we haven't parsed the initializer of the pattern yet because // we are waiting for the closing brace of the outer class. Expr *OldInit = Pattern->getInClassInitializer(); if (!OldInit) { RecordDecl *PatternRD = Pattern->getParent(); RecordDecl *OutermostClass = PatternRD->getOuterLexicalRecordContext(); if (OutermostClass == PatternRD) { Diag(Pattern->getLocEnd(), diag::err_in_class_initializer_not_yet_parsed) << PatternRD << Pattern; } else { Diag(Pattern->getLocEnd(), diag::err_in_class_initializer_not_yet_parsed_outer_class) << PatternRD << OutermostClass << Pattern; } Instantiation->setInvalidDecl(); return true; } InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); if (Inst.isInvalid()) return true; // Enter the scope of this instantiation. We don't use PushDeclContext because // we don't have a scope. ContextRAII SavedContext(*this, Instantiation->getParent()); EnterExpressionEvaluationContext EvalContext(*this, Sema::PotentiallyEvaluated); LocalInstantiationScope Scope(*this); // Instantiate the initializer. ActOnStartCXXInClassMemberInitializer(); CXXThisScopeRAII ThisScope(*this, Instantiation->getParent(), /*TypeQuals=*/0); ExprResult NewInit = SubstInitializer(OldInit, TemplateArgs, /*CXXDirectInit=*/false); Expr *Init = NewInit.get(); assert((!Init || !isa(Init)) && "call-style init in class"); ActOnFinishCXXInClassMemberInitializer( Instantiation, Init ? Init->getLocStart() : SourceLocation(), Init); // Exit the scope of this instantiation. SavedContext.pop(); // Return true if the in-class initializer is still missing. return !Instantiation->getInClassInitializer(); } namespace { /// \brief A partial specialization whose template arguments have matched /// a given template-id. struct PartialSpecMatchResult { ClassTemplatePartialSpecializationDecl *Partial; TemplateArgumentList *Args; }; } bool Sema::InstantiateClassTemplateSpecialization( SourceLocation PointOfInstantiation, ClassTemplateSpecializationDecl *ClassTemplateSpec, TemplateSpecializationKind TSK, bool Complain) { // Perform the actual instantiation on the canonical declaration. ClassTemplateSpec = cast( ClassTemplateSpec->getCanonicalDecl()); // Check whether we have already instantiated or specialized this class // template specialization. if (ClassTemplateSpec->getSpecializationKind() != TSK_Undeclared) { if (ClassTemplateSpec->getSpecializationKind() == TSK_ExplicitInstantiationDeclaration && TSK == TSK_ExplicitInstantiationDefinition) { // An explicit instantiation definition follows an explicit instantiation // declaration (C++0x [temp.explicit]p10); go ahead and perform the // explicit instantiation. ClassTemplateSpec->setSpecializationKind(TSK); // If this is an explicit instantiation definition, mark the // vtable as used. if (TSK == TSK_ExplicitInstantiationDefinition && !ClassTemplateSpec->isInvalidDecl()) MarkVTableUsed(PointOfInstantiation, ClassTemplateSpec, true); return false; } // We can only instantiate something that hasn't already been // instantiated or specialized. Fail without any diagnostics: our // caller will provide an error message. return true; } if (ClassTemplateSpec->isInvalidDecl()) return true; ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate(); CXXRecordDecl *Pattern = nullptr; // C++ [temp.class.spec.match]p1: // When a class template is used in a context that requires an // instantiation of the class, it is necessary to determine // whether the instantiation is to be generated using the primary // template or one of the partial specializations. This is done by // matching the template arguments of the class template // specialization with the template argument lists of the partial // specializations. typedef PartialSpecMatchResult MatchResult; SmallVector Matched; SmallVector PartialSpecs; Template->getPartialSpecializations(PartialSpecs); TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation); for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) { ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I]; TemplateDeductionInfo Info(FailedCandidates.getLocation()); if (TemplateDeductionResult Result = DeduceTemplateArguments(Partial, ClassTemplateSpec->getTemplateArgs(), Info)) { // Store the failed-deduction information for use in diagnostics, later. // TODO: Actually use the failed-deduction info? FailedCandidates.addCandidate() .set(Partial, MakeDeductionFailureInfo(Context, Result, Info)); (void)Result; } else { Matched.push_back(PartialSpecMatchResult()); Matched.back().Partial = Partial; Matched.back().Args = Info.take(); } } // If we're dealing with a member template where the template parameters // have been instantiated, this provides the original template parameters // from which the member template's parameters were instantiated. if (Matched.size() >= 1) { SmallVectorImpl::iterator Best = Matched.begin(); if (Matched.size() == 1) { // -- If exactly one matching specialization is found, the // instantiation is generated from that specialization. // We don't need to do anything for this. } else { // -- If more than one matching specialization is found, the // partial order rules (14.5.4.2) are used to determine // whether one of the specializations is more specialized // than the others. If none of the specializations is more // specialized than all of the other matching // specializations, then the use of the class template is // ambiguous and the program is ill-formed. for (SmallVectorImpl::iterator P = Best + 1, PEnd = Matched.end(); P != PEnd; ++P) { if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial, PointOfInstantiation) == P->Partial) Best = P; } // Determine if the best partial specialization is more specialized than // the others. bool Ambiguous = false; for (SmallVectorImpl::iterator P = Matched.begin(), PEnd = Matched.end(); P != PEnd; ++P) { if (P != Best && getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial, PointOfInstantiation) != Best->Partial) { Ambiguous = true; break; } } if (Ambiguous) { // Partial ordering did not produce a clear winner. Complain. ClassTemplateSpec->setInvalidDecl(); Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous) << ClassTemplateSpec; // Print the matching partial specializations. for (SmallVectorImpl::iterator P = Matched.begin(), PEnd = Matched.end(); P != PEnd; ++P) Diag(P->Partial->getLocation(), diag::note_partial_spec_match) << getTemplateArgumentBindingsText( P->Partial->getTemplateParameters(), *P->Args); return true; } } // Instantiate using the best class template partial specialization. ClassTemplatePartialSpecializationDecl *OrigPartialSpec = Best->Partial; while (OrigPartialSpec->getInstantiatedFromMember()) { // If we've found an explicit specialization of this class template, // stop here and use that as the pattern. if (OrigPartialSpec->isMemberSpecialization()) break; OrigPartialSpec = OrigPartialSpec->getInstantiatedFromMember(); } Pattern = OrigPartialSpec; ClassTemplateSpec->setInstantiationOf(Best->Partial, Best->Args); } else { // -- If no matches are found, the instantiation is generated // from the primary template. ClassTemplateDecl *OrigTemplate = Template; while (OrigTemplate->getInstantiatedFromMemberTemplate()) { // If we've found an explicit specialization of this class template, // stop here and use that as the pattern. if (OrigTemplate->isMemberSpecialization()) break; OrigTemplate = OrigTemplate->getInstantiatedFromMemberTemplate(); } Pattern = OrigTemplate->getTemplatedDecl(); } bool Result = InstantiateClass(PointOfInstantiation, ClassTemplateSpec, Pattern, getTemplateInstantiationArgs(ClassTemplateSpec), TSK, Complain); return Result; } /// \brief Instantiates the definitions of all of the member /// of the given class, which is an instantiation of a class template /// or a member class of a template. void Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation, CXXRecordDecl *Instantiation, const MultiLevelTemplateArgumentList &TemplateArgs, TemplateSpecializationKind TSK) { // FIXME: We need to notify the ASTMutationListener that we did all of these // things, in case we have an explicit instantiation definition in a PCM, a // module, or preamble, and the declaration is in an imported AST. assert( (TSK == TSK_ExplicitInstantiationDefinition || TSK == TSK_ExplicitInstantiationDeclaration || (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) && "Unexpected template specialization kind!"); for (auto *D : Instantiation->decls()) { bool SuppressNew = false; if (auto *Function = dyn_cast(D)) { if (FunctionDecl *Pattern = Function->getInstantiatedFromMemberFunction()) { MemberSpecializationInfo *MSInfo = Function->getMemberSpecializationInfo(); assert(MSInfo && "No member specialization information?"); if (MSInfo->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) continue; if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, Function, MSInfo->getTemplateSpecializationKind(), MSInfo->getPointOfInstantiation(), SuppressNew) || SuppressNew) continue; // C++11 [temp.explicit]p8: // An explicit instantiation definition that names a class template // specialization explicitly instantiates the class template // specialization and is only an explicit instantiation definition // of members whose definition is visible at the point of // instantiation. if (TSK == TSK_ExplicitInstantiationDefinition && !Pattern->isDefined()) continue; Function->setTemplateSpecializationKind(TSK, PointOfInstantiation); if (Function->isDefined()) { // Let the ASTConsumer know that this function has been explicitly // instantiated now, and its linkage might have changed. Consumer.HandleTopLevelDecl(DeclGroupRef(Function)); } else if (TSK == TSK_ExplicitInstantiationDefinition) { InstantiateFunctionDefinition(PointOfInstantiation, Function); } else if (TSK == TSK_ImplicitInstantiation) { PendingLocalImplicitInstantiations.push_back( std::make_pair(Function, PointOfInstantiation)); } } } else if (auto *Var = dyn_cast(D)) { if (isa(Var)) continue; if (Var->isStaticDataMember()) { MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo(); assert(MSInfo && "No member specialization information?"); if (MSInfo->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) continue; if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, Var, MSInfo->getTemplateSpecializationKind(), MSInfo->getPointOfInstantiation(), SuppressNew) || SuppressNew) continue; if (TSK == TSK_ExplicitInstantiationDefinition) { // C++0x [temp.explicit]p8: // An explicit instantiation definition that names a class template // specialization explicitly instantiates the class template // specialization and is only an explicit instantiation definition // of members whose definition is visible at the point of // instantiation. if (!Var->getInstantiatedFromStaticDataMember() ->getOutOfLineDefinition()) continue; Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); InstantiateStaticDataMemberDefinition(PointOfInstantiation, Var); } else { Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); } } } else if (auto *Record = dyn_cast(D)) { // Always skip the injected-class-name, along with any // redeclarations of nested classes, since both would cause us // to try to instantiate the members of a class twice. // Skip closure types; they'll get instantiated when we instantiate // the corresponding lambda-expression. if (Record->isInjectedClassName() || Record->getPreviousDecl() || Record->isLambda()) continue; MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo(); assert(MSInfo && "No member specialization information?"); if (MSInfo->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) continue; if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, Record, MSInfo->getTemplateSpecializationKind(), MSInfo->getPointOfInstantiation(), SuppressNew) || SuppressNew) continue; CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass(); assert(Pattern && "Missing instantiated-from-template information"); if (!Record->getDefinition()) { if (!Pattern->getDefinition()) { // C++0x [temp.explicit]p8: // An explicit instantiation definition that names a class template // specialization explicitly instantiates the class template // specialization and is only an explicit instantiation definition // of members whose definition is visible at the point of // instantiation. if (TSK == TSK_ExplicitInstantiationDeclaration) { MSInfo->setTemplateSpecializationKind(TSK); MSInfo->setPointOfInstantiation(PointOfInstantiation); } continue; } InstantiateClass(PointOfInstantiation, Record, Pattern, TemplateArgs, TSK); } else { if (TSK == TSK_ExplicitInstantiationDefinition && Record->getTemplateSpecializationKind() == TSK_ExplicitInstantiationDeclaration) { Record->setTemplateSpecializationKind(TSK); MarkVTableUsed(PointOfInstantiation, Record, true); } } Pattern = cast_or_null(Record->getDefinition()); if (Pattern) InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs, TSK); } else if (auto *Enum = dyn_cast(D)) { MemberSpecializationInfo *MSInfo = Enum->getMemberSpecializationInfo(); assert(MSInfo && "No member specialization information?"); if (MSInfo->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) continue; if (CheckSpecializationInstantiationRedecl( PointOfInstantiation, TSK, Enum, MSInfo->getTemplateSpecializationKind(), MSInfo->getPointOfInstantiation(), SuppressNew) || SuppressNew) continue; if (Enum->getDefinition()) continue; EnumDecl *Pattern = Enum->getInstantiatedFromMemberEnum(); assert(Pattern && "Missing instantiated-from-template information"); if (TSK == TSK_ExplicitInstantiationDefinition) { if (!Pattern->getDefinition()) continue; InstantiateEnum(PointOfInstantiation, Enum, Pattern, TemplateArgs, TSK); } else { MSInfo->setTemplateSpecializationKind(TSK); MSInfo->setPointOfInstantiation(PointOfInstantiation); } } else if (auto *Field = dyn_cast(D)) { // No need to instantiate in-class initializers during explicit // instantiation. if (Field->hasInClassInitializer() && TSK == TSK_ImplicitInstantiation) { CXXRecordDecl *ClassPattern = Instantiation->getTemplateInstantiationPattern(); DeclContext::lookup_result Lookup = ClassPattern->lookup(Field->getDeclName()); assert(Lookup.size() == 1); FieldDecl *Pattern = cast(Lookup[0]); InstantiateInClassInitializer(PointOfInstantiation, Field, Pattern, TemplateArgs); } } } } /// \brief Instantiate the definitions of all of the members of the /// given class template specialization, which was named as part of an /// explicit instantiation. void Sema::InstantiateClassTemplateSpecializationMembers( SourceLocation PointOfInstantiation, ClassTemplateSpecializationDecl *ClassTemplateSpec, TemplateSpecializationKind TSK) { // C++0x [temp.explicit]p7: // An explicit instantiation that names a class template // specialization is an explicit instantion of the same kind // (declaration or definition) of each of its members (not // including members inherited from base classes) that has not // been previously explicitly specialized in the translation unit // containing the explicit instantiation, except as described // below. InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec, getTemplateInstantiationArgs(ClassTemplateSpec), TSK); } StmtResult Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) { if (!S) return S; TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); return Instantiator.TransformStmt(S); } ExprResult Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) { if (!E) return E; TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); return Instantiator.TransformExpr(E); } ExprResult Sema::SubstInitializer(Expr *Init, const MultiLevelTemplateArgumentList &TemplateArgs, bool CXXDirectInit) { TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); return Instantiator.TransformInitializer(Init, CXXDirectInit); } bool Sema::SubstExprs(Expr **Exprs, unsigned NumExprs, bool IsCall, const MultiLevelTemplateArgumentList &TemplateArgs, SmallVectorImpl &Outputs) { if (NumExprs == 0) return false; TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); return Instantiator.TransformExprs(Exprs, NumExprs, IsCall, Outputs); } NestedNameSpecifierLoc Sema::SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS, const MultiLevelTemplateArgumentList &TemplateArgs) { if (!NNS) return NestedNameSpecifierLoc(); TemplateInstantiator Instantiator(*this, TemplateArgs, NNS.getBeginLoc(), DeclarationName()); return Instantiator.TransformNestedNameSpecifierLoc(NNS); } /// \brief Do template substitution on declaration name info. DeclarationNameInfo Sema::SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo, const MultiLevelTemplateArgumentList &TemplateArgs) { TemplateInstantiator Instantiator(*this, TemplateArgs, NameInfo.getLoc(), NameInfo.getName()); return Instantiator.TransformDeclarationNameInfo(NameInfo); } TemplateName Sema::SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, TemplateName Name, SourceLocation Loc, const MultiLevelTemplateArgumentList &TemplateArgs) { TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, DeclarationName()); CXXScopeSpec SS; SS.Adopt(QualifierLoc); return Instantiator.TransformTemplateName(SS, Name, Loc); } bool Sema::Subst(const TemplateArgumentLoc *Args, unsigned NumArgs, TemplateArgumentListInfo &Result, const MultiLevelTemplateArgumentList &TemplateArgs) { TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); return Instantiator.TransformTemplateArguments(Args, NumArgs, Result); } static const Decl *getCanonicalParmVarDecl(const Decl *D) { // When storing ParmVarDecls in the local instantiation scope, we always // want to use the ParmVarDecl from the canonical function declaration, // since the map is then valid for any redeclaration or definition of that // function. if (const ParmVarDecl *PV = dyn_cast(D)) { if (const FunctionDecl *FD = dyn_cast(PV->getDeclContext())) { unsigned i = PV->getFunctionScopeIndex(); // This parameter might be from a freestanding function type within the // function and isn't necessarily referring to one of FD's parameters. if (FD->getParamDecl(i) == PV) return FD->getCanonicalDecl()->getParamDecl(i); } } return D; } llvm::PointerUnion * LocalInstantiationScope::findInstantiationOf(const Decl *D) { D = getCanonicalParmVarDecl(D); for (LocalInstantiationScope *Current = this; Current; Current = Current->Outer) { // Check if we found something within this scope. const Decl *CheckD = D; do { LocalDeclsMap::iterator Found = Current->LocalDecls.find(CheckD); if (Found != Current->LocalDecls.end()) return &Found->second; // If this is a tag declaration, it's possible that we need to look for // a previous declaration. if (const TagDecl *Tag = dyn_cast(CheckD)) CheckD = Tag->getPreviousDecl(); else CheckD = nullptr; } while (CheckD); // If we aren't combined with our outer scope, we're done. if (!Current->CombineWithOuterScope) break; } // If we're performing a partial substitution during template argument // deduction, we may not have values for template parameters yet. if (isa(D) || isa(D) || isa(D)) return nullptr; // If we didn't find the decl, then we either have a sema bug, or we have a // forward reference to a label declaration. Return null to indicate that // we have an uninstantiated label. assert(isa(D) && "declaration not instantiated in this scope"); return nullptr; } void LocalInstantiationScope::InstantiatedLocal(const Decl *D, Decl *Inst) { D = getCanonicalParmVarDecl(D); llvm::PointerUnion &Stored = LocalDecls[D]; if (Stored.isNull()) { #ifndef NDEBUG // It should not be present in any surrounding scope either. LocalInstantiationScope *Current = this; while (Current->CombineWithOuterScope && Current->Outer) { Current = Current->Outer; assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() && "Instantiated local in inner and outer scopes"); } #endif Stored = Inst; } else if (DeclArgumentPack *Pack = Stored.dyn_cast()) { Pack->push_back(Inst); } else { assert(Stored.get() == Inst && "Already instantiated this local"); } } void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D, Decl *Inst) { D = getCanonicalParmVarDecl(D); DeclArgumentPack *Pack = LocalDecls[D].get(); Pack->push_back(Inst); } void LocalInstantiationScope::MakeInstantiatedLocalArgPack(const Decl *D) { #ifndef NDEBUG // This should be the first time we've been told about this decl. for (LocalInstantiationScope *Current = this; Current && Current->CombineWithOuterScope; Current = Current->Outer) assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() && "Creating local pack after instantiation of local"); #endif D = getCanonicalParmVarDecl(D); llvm::PointerUnion &Stored = LocalDecls[D]; DeclArgumentPack *Pack = new DeclArgumentPack; Stored = Pack; ArgumentPacks.push_back(Pack); } void LocalInstantiationScope::SetPartiallySubstitutedPack(NamedDecl *Pack, const TemplateArgument *ExplicitArgs, unsigned NumExplicitArgs) { assert((!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) && "Already have a partially-substituted pack"); assert((!PartiallySubstitutedPack || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) && "Wrong number of arguments in partially-substituted pack"); PartiallySubstitutedPack = Pack; ArgsInPartiallySubstitutedPack = ExplicitArgs; NumArgsInPartiallySubstitutedPack = NumExplicitArgs; } NamedDecl *LocalInstantiationScope::getPartiallySubstitutedPack( const TemplateArgument **ExplicitArgs, unsigned *NumExplicitArgs) const { if (ExplicitArgs) *ExplicitArgs = nullptr; if (NumExplicitArgs) *NumExplicitArgs = 0; for (const LocalInstantiationScope *Current = this; Current; Current = Current->Outer) { if (Current->PartiallySubstitutedPack) { if (ExplicitArgs) *ExplicitArgs = Current->ArgsInPartiallySubstitutedPack; if (NumExplicitArgs) *NumExplicitArgs = Current->NumArgsInPartiallySubstitutedPack; return Current->PartiallySubstitutedPack; } if (!Current->CombineWithOuterScope) break; } return nullptr; }