| //===------- SemaTemplateVariadic.cpp - C++ Variadic Templates ------------===/ |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| //===----------------------------------------------------------------------===/ |
| // |
| // This file implements semantic analysis for C++0x variadic templates. |
| //===----------------------------------------------------------------------===/ |
| |
| #include "clang/Sema/Sema.h" |
| #include "TypeLocBuilder.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/RecursiveASTVisitor.h" |
| #include "clang/AST/TypeLoc.h" |
| #include "clang/Sema/Lookup.h" |
| #include "clang/Sema/ParsedTemplate.h" |
| #include "clang/Sema/ScopeInfo.h" |
| #include "clang/Sema/SemaInternal.h" |
| #include "clang/Sema/Template.h" |
| |
| using namespace clang; |
| |
| //---------------------------------------------------------------------------- |
| // Visitor that collects unexpanded parameter packs |
| //---------------------------------------------------------------------------- |
| |
| namespace { |
| /// A class that collects unexpanded parameter packs. |
| class CollectUnexpandedParameterPacksVisitor : |
| public RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor> |
| { |
| typedef RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor> |
| inherited; |
| |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded; |
| |
| bool InLambda = false; |
| unsigned DepthLimit = (unsigned)-1; |
| |
| void addUnexpanded(NamedDecl *ND, SourceLocation Loc = SourceLocation()) { |
| if (auto *VD = dyn_cast<VarDecl>(ND)) { |
| // For now, the only problematic case is a generic lambda's templated |
| // call operator, so we don't need to look for all the other ways we |
| // could have reached a dependent parameter pack. |
| auto *FD = dyn_cast<FunctionDecl>(VD->getDeclContext()); |
| auto *FTD = FD ? FD->getDescribedFunctionTemplate() : nullptr; |
| if (FTD && FTD->getTemplateParameters()->getDepth() >= DepthLimit) |
| return; |
| } else if (getDepthAndIndex(ND).first >= DepthLimit) |
| return; |
| |
| Unexpanded.push_back({ND, Loc}); |
| } |
| void addUnexpanded(const TemplateTypeParmType *T, |
| SourceLocation Loc = SourceLocation()) { |
| if (T->getDepth() < DepthLimit) |
| Unexpanded.push_back({T, Loc}); |
| } |
| |
| public: |
| explicit CollectUnexpandedParameterPacksVisitor( |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) |
| : Unexpanded(Unexpanded) {} |
| |
| bool shouldWalkTypesOfTypeLocs() const { return false; } |
| |
| //------------------------------------------------------------------------ |
| // Recording occurrences of (unexpanded) parameter packs. |
| //------------------------------------------------------------------------ |
| |
| /// Record occurrences of template type parameter packs. |
| bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) { |
| if (TL.getTypePtr()->isParameterPack()) |
| addUnexpanded(TL.getTypePtr(), TL.getNameLoc()); |
| return true; |
| } |
| |
| /// Record occurrences of template type parameter packs |
| /// when we don't have proper source-location information for |
| /// them. |
| /// |
| /// Ideally, this routine would never be used. |
| bool VisitTemplateTypeParmType(TemplateTypeParmType *T) { |
| if (T->isParameterPack()) |
| addUnexpanded(T); |
| |
| return true; |
| } |
| |
| /// Record occurrences of function and non-type template |
| /// parameter packs in an expression. |
| bool VisitDeclRefExpr(DeclRefExpr *E) { |
| if (E->getDecl()->isParameterPack()) |
| addUnexpanded(E->getDecl(), E->getLocation()); |
| |
| return true; |
| } |
| |
| /// Record occurrences of template template parameter packs. |
| bool TraverseTemplateName(TemplateName Template) { |
| if (auto *TTP = dyn_cast_or_null<TemplateTemplateParmDecl>( |
| Template.getAsTemplateDecl())) { |
| if (TTP->isParameterPack()) |
| addUnexpanded(TTP); |
| } |
| |
| return inherited::TraverseTemplateName(Template); |
| } |
| |
| /// Suppress traversal into Objective-C container literal |
| /// elements that are pack expansions. |
| bool TraverseObjCDictionaryLiteral(ObjCDictionaryLiteral *E) { |
| if (!E->containsUnexpandedParameterPack()) |
| return true; |
| |
| for (unsigned I = 0, N = E->getNumElements(); I != N; ++I) { |
| ObjCDictionaryElement Element = E->getKeyValueElement(I); |
| if (Element.isPackExpansion()) |
| continue; |
| |
| TraverseStmt(Element.Key); |
| TraverseStmt(Element.Value); |
| } |
| return true; |
| } |
| //------------------------------------------------------------------------ |
| // Pruning the search for unexpanded parameter packs. |
| //------------------------------------------------------------------------ |
| |
| /// Suppress traversal into statements and expressions that |
| /// do not contain unexpanded parameter packs. |
| bool TraverseStmt(Stmt *S) { |
| Expr *E = dyn_cast_or_null<Expr>(S); |
| if ((E && E->containsUnexpandedParameterPack()) || InLambda) |
| return inherited::TraverseStmt(S); |
| |
| return true; |
| } |
| |
| /// Suppress traversal into types that do not contain |
| /// unexpanded parameter packs. |
| bool TraverseType(QualType T) { |
| if ((!T.isNull() && T->containsUnexpandedParameterPack()) || InLambda) |
| return inherited::TraverseType(T); |
| |
| return true; |
| } |
| |
| /// Suppress traversal into types with location information |
| /// that do not contain unexpanded parameter packs. |
| bool TraverseTypeLoc(TypeLoc TL) { |
| if ((!TL.getType().isNull() && |
| TL.getType()->containsUnexpandedParameterPack()) || |
| InLambda) |
| return inherited::TraverseTypeLoc(TL); |
| |
| return true; |
| } |
| |
| /// Suppress traversal of parameter packs. |
| bool TraverseDecl(Decl *D) { |
| // A function parameter pack is a pack expansion, so cannot contain |
| // an unexpanded parameter pack. Likewise for a template parameter |
| // pack that contains any references to other packs. |
| if (D && D->isParameterPack()) |
| return true; |
| |
| return inherited::TraverseDecl(D); |
| } |
| |
| /// Suppress traversal of pack-expanded attributes. |
| bool TraverseAttr(Attr *A) { |
| if (A->isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseAttr(A); |
| } |
| |
| /// Suppress traversal of pack expansion expressions and types. |
| ///@{ |
| bool TraversePackExpansionType(PackExpansionType *T) { return true; } |
| bool TraversePackExpansionTypeLoc(PackExpansionTypeLoc TL) { return true; } |
| bool TraversePackExpansionExpr(PackExpansionExpr *E) { return true; } |
| bool TraverseCXXFoldExpr(CXXFoldExpr *E) { return true; } |
| |
| ///@} |
| |
| /// Suppress traversal of using-declaration pack expansion. |
| bool TraverseUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) { |
| if (D->isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseUnresolvedUsingValueDecl(D); |
| } |
| |
| /// Suppress traversal of using-declaration pack expansion. |
| bool TraverseUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) { |
| if (D->isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseUnresolvedUsingTypenameDecl(D); |
| } |
| |
| /// Suppress traversal of template argument pack expansions. |
| bool TraverseTemplateArgument(const TemplateArgument &Arg) { |
| if (Arg.isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseTemplateArgument(Arg); |
| } |
| |
| /// Suppress traversal of template argument pack expansions. |
| bool TraverseTemplateArgumentLoc(const TemplateArgumentLoc &ArgLoc) { |
| if (ArgLoc.getArgument().isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseTemplateArgumentLoc(ArgLoc); |
| } |
| |
| /// Suppress traversal of base specifier pack expansions. |
| bool TraverseCXXBaseSpecifier(const CXXBaseSpecifier &Base) { |
| if (Base.isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseCXXBaseSpecifier(Base); |
| } |
| |
| /// Suppress traversal of mem-initializer pack expansions. |
| bool TraverseConstructorInitializer(CXXCtorInitializer *Init) { |
| if (Init->isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseConstructorInitializer(Init); |
| } |
| |
| /// Note whether we're traversing a lambda containing an unexpanded |
| /// parameter pack. In this case, the unexpanded pack can occur anywhere, |
| /// including all the places where we normally wouldn't look. Within a |
| /// lambda, we don't propagate the 'contains unexpanded parameter pack' bit |
| /// outside an expression. |
| bool TraverseLambdaExpr(LambdaExpr *Lambda) { |
| // The ContainsUnexpandedParameterPack bit on a lambda is always correct, |
| // even if it's contained within another lambda. |
| if (!Lambda->containsUnexpandedParameterPack()) |
| return true; |
| |
| bool WasInLambda = InLambda; |
| unsigned OldDepthLimit = DepthLimit; |
| |
| InLambda = true; |
| if (auto *TPL = Lambda->getTemplateParameterList()) |
| DepthLimit = TPL->getDepth(); |
| |
| inherited::TraverseLambdaExpr(Lambda); |
| |
| InLambda = WasInLambda; |
| DepthLimit = OldDepthLimit; |
| return true; |
| } |
| |
| /// Suppress traversal within pack expansions in lambda captures. |
| bool TraverseLambdaCapture(LambdaExpr *Lambda, const LambdaCapture *C, |
| Expr *Init) { |
| if (C->isPackExpansion()) |
| return true; |
| |
| return inherited::TraverseLambdaCapture(Lambda, C, Init); |
| } |
| }; |
| } |
| |
| /// Determine whether it's possible for an unexpanded parameter pack to |
| /// be valid in this location. This only happens when we're in a declaration |
| /// that is nested within an expression that could be expanded, such as a |
| /// lambda-expression within a function call. |
| /// |
| /// This is conservatively correct, but may claim that some unexpanded packs are |
| /// permitted when they are not. |
| bool Sema::isUnexpandedParameterPackPermitted() { |
| for (auto *SI : FunctionScopes) |
| if (isa<sema::LambdaScopeInfo>(SI)) |
| return true; |
| return false; |
| } |
| |
| /// Diagnose all of the unexpanded parameter packs in the given |
| /// vector. |
| bool |
| Sema::DiagnoseUnexpandedParameterPacks(SourceLocation Loc, |
| UnexpandedParameterPackContext UPPC, |
| ArrayRef<UnexpandedParameterPack> Unexpanded) { |
| if (Unexpanded.empty()) |
| return false; |
| |
| // If we are within a lambda expression and referencing a pack that is not |
| // declared within the lambda itself, that lambda contains an unexpanded |
| // parameter pack, and we are done. |
| // FIXME: Store 'Unexpanded' on the lambda so we don't need to recompute it |
| // later. |
| SmallVector<UnexpandedParameterPack, 4> LambdaParamPackReferences; |
| if (auto *LSI = getEnclosingLambda()) { |
| for (auto &Pack : Unexpanded) { |
| auto DeclaresThisPack = [&](NamedDecl *LocalPack) { |
| if (auto *TTPT = Pack.first.dyn_cast<const TemplateTypeParmType *>()) { |
| auto *TTPD = dyn_cast<TemplateTypeParmDecl>(LocalPack); |
| return TTPD && TTPD->getTypeForDecl() == TTPT; |
| } |
| return declaresSameEntity(Pack.first.get<NamedDecl *>(), LocalPack); |
| }; |
| if (std::find_if(LSI->LocalPacks.begin(), LSI->LocalPacks.end(), |
| DeclaresThisPack) != LSI->LocalPacks.end()) |
| LambdaParamPackReferences.push_back(Pack); |
| } |
| |
| if (LambdaParamPackReferences.empty()) { |
| // Construct in lambda only references packs declared outside the lambda. |
| // That's OK for now, but the lambda itself is considered to contain an |
| // unexpanded pack in this case, which will require expansion outside the |
| // lambda. |
| |
| // We do not permit pack expansion that would duplicate a statement |
| // expression, not even within a lambda. |
| // FIXME: We could probably support this for statement expressions that |
| // do not contain labels. |
| // FIXME: This is insufficient to detect this problem; consider |
| // f( ({ bad: 0; }) + pack ... ); |
| bool EnclosingStmtExpr = false; |
| for (unsigned N = FunctionScopes.size(); N; --N) { |
| sema::FunctionScopeInfo *Func = FunctionScopes[N-1]; |
| if (std::any_of( |
| Func->CompoundScopes.begin(), Func->CompoundScopes.end(), |
| [](sema::CompoundScopeInfo &CSI) { return CSI.IsStmtExpr; })) { |
| EnclosingStmtExpr = true; |
| break; |
| } |
| // Coumpound-statements outside the lambda are OK for now; we'll check |
| // for those when we finish handling the lambda. |
| if (Func == LSI) |
| break; |
| } |
| |
| if (!EnclosingStmtExpr) { |
| LSI->ContainsUnexpandedParameterPack = true; |
| return false; |
| } |
| } else { |
| Unexpanded = LambdaParamPackReferences; |
| } |
| } |
| |
| SmallVector<SourceLocation, 4> Locations; |
| SmallVector<IdentifierInfo *, 4> Names; |
| llvm::SmallPtrSet<IdentifierInfo *, 4> NamesKnown; |
| |
| for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { |
| IdentifierInfo *Name = nullptr; |
| if (const TemplateTypeParmType *TTP |
| = Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>()) |
| Name = TTP->getIdentifier(); |
| else |
| Name = Unexpanded[I].first.get<NamedDecl *>()->getIdentifier(); |
| |
| if (Name && NamesKnown.insert(Name).second) |
| Names.push_back(Name); |
| |
| if (Unexpanded[I].second.isValid()) |
| Locations.push_back(Unexpanded[I].second); |
| } |
| |
| DiagnosticBuilder DB = Diag(Loc, diag::err_unexpanded_parameter_pack) |
| << (int)UPPC << (int)Names.size(); |
| for (size_t I = 0, E = std::min(Names.size(), (size_t)2); I != E; ++I) |
| DB << Names[I]; |
| |
| for (unsigned I = 0, N = Locations.size(); I != N; ++I) |
| DB << SourceRange(Locations[I]); |
| return true; |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc, |
| TypeSourceInfo *T, |
| UnexpandedParameterPackContext UPPC) { |
| // C++0x [temp.variadic]p5: |
| // An appearance of a name of a parameter pack that is not expanded is |
| // ill-formed. |
| if (!T->getType()->containsUnexpandedParameterPack()) |
| return false; |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc( |
| T->getTypeLoc()); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded); |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(Expr *E, |
| UnexpandedParameterPackContext UPPC) { |
| // C++0x [temp.variadic]p5: |
| // An appearance of a name of a parameter pack that is not expanded is |
| // ill-formed. |
| if (!E->containsUnexpandedParameterPack()) |
| return false; |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseStmt(E); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(E->getBeginLoc(), UPPC, Unexpanded); |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS, |
| UnexpandedParameterPackContext UPPC) { |
| // C++0x [temp.variadic]p5: |
| // An appearance of a name of a parameter pack that is not expanded is |
| // ill-formed. |
| if (!SS.getScopeRep() || |
| !SS.getScopeRep()->containsUnexpandedParameterPack()) |
| return false; |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseNestedNameSpecifier(SS.getScopeRep()); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(SS.getRange().getBegin(), |
| UPPC, Unexpanded); |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo, |
| UnexpandedParameterPackContext UPPC) { |
| // C++0x [temp.variadic]p5: |
| // An appearance of a name of a parameter pack that is not expanded is |
| // ill-formed. |
| switch (NameInfo.getName().getNameKind()) { |
| case DeclarationName::Identifier: |
| case DeclarationName::ObjCZeroArgSelector: |
| case DeclarationName::ObjCOneArgSelector: |
| case DeclarationName::ObjCMultiArgSelector: |
| case DeclarationName::CXXOperatorName: |
| case DeclarationName::CXXLiteralOperatorName: |
| case DeclarationName::CXXUsingDirective: |
| case DeclarationName::CXXDeductionGuideName: |
| return false; |
| |
| case DeclarationName::CXXConstructorName: |
| case DeclarationName::CXXDestructorName: |
| case DeclarationName::CXXConversionFunctionName: |
| // FIXME: We shouldn't need this null check! |
| if (TypeSourceInfo *TSInfo = NameInfo.getNamedTypeInfo()) |
| return DiagnoseUnexpandedParameterPack(NameInfo.getLoc(), TSInfo, UPPC); |
| |
| if (!NameInfo.getName().getCXXNameType()->containsUnexpandedParameterPack()) |
| return false; |
| |
| break; |
| } |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseType(NameInfo.getName().getCXXNameType()); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(NameInfo.getLoc(), UPPC, Unexpanded); |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc, |
| TemplateName Template, |
| UnexpandedParameterPackContext UPPC) { |
| |
| if (Template.isNull() || !Template.containsUnexpandedParameterPack()) |
| return false; |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseTemplateName(Template); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded); |
| } |
| |
| bool Sema::DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg, |
| UnexpandedParameterPackContext UPPC) { |
| if (Arg.getArgument().isNull() || |
| !Arg.getArgument().containsUnexpandedParameterPack()) |
| return false; |
| |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseTemplateArgumentLoc(Arg); |
| assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs"); |
| return DiagnoseUnexpandedParameterPacks(Arg.getLocation(), UPPC, Unexpanded); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks(TemplateArgument Arg, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseTemplateArgument(Arg); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks(TemplateArgumentLoc Arg, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseTemplateArgumentLoc(Arg); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks(QualType T, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(T); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks(TypeLoc TL, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(TL); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks( |
| NestedNameSpecifierLoc NNS, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseNestedNameSpecifierLoc(NNS); |
| } |
| |
| void Sema::collectUnexpandedParameterPacks( |
| const DeclarationNameInfo &NameInfo, |
| SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) { |
| CollectUnexpandedParameterPacksVisitor(Unexpanded) |
| .TraverseDeclarationNameInfo(NameInfo); |
| } |
| |
| |
| ParsedTemplateArgument |
| Sema::ActOnPackExpansion(const ParsedTemplateArgument &Arg, |
| SourceLocation EllipsisLoc) { |
| if (Arg.isInvalid()) |
| return Arg; |
| |
| switch (Arg.getKind()) { |
| case ParsedTemplateArgument::Type: { |
| TypeResult Result = ActOnPackExpansion(Arg.getAsType(), EllipsisLoc); |
| if (Result.isInvalid()) |
| return ParsedTemplateArgument(); |
| |
| return ParsedTemplateArgument(Arg.getKind(), Result.get().getAsOpaquePtr(), |
| Arg.getLocation()); |
| } |
| |
| case ParsedTemplateArgument::NonType: { |
| ExprResult Result = ActOnPackExpansion(Arg.getAsExpr(), EllipsisLoc); |
| if (Result.isInvalid()) |
| return ParsedTemplateArgument(); |
| |
| return ParsedTemplateArgument(Arg.getKind(), Result.get(), |
| Arg.getLocation()); |
| } |
| |
| case ParsedTemplateArgument::Template: |
| if (!Arg.getAsTemplate().get().containsUnexpandedParameterPack()) { |
| SourceRange R(Arg.getLocation()); |
| if (Arg.getScopeSpec().isValid()) |
| R.setBegin(Arg.getScopeSpec().getBeginLoc()); |
| Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs) |
| << R; |
| return ParsedTemplateArgument(); |
| } |
| |
| return Arg.getTemplatePackExpansion(EllipsisLoc); |
| } |
| llvm_unreachable("Unhandled template argument kind?"); |
| } |
| |
| TypeResult Sema::ActOnPackExpansion(ParsedType Type, |
| SourceLocation EllipsisLoc) { |
| TypeSourceInfo *TSInfo; |
| GetTypeFromParser(Type, &TSInfo); |
| if (!TSInfo) |
| return true; |
| |
| TypeSourceInfo *TSResult = CheckPackExpansion(TSInfo, EllipsisLoc, None); |
| if (!TSResult) |
| return true; |
| |
| return CreateParsedType(TSResult->getType(), TSResult); |
| } |
| |
| TypeSourceInfo * |
| Sema::CheckPackExpansion(TypeSourceInfo *Pattern, SourceLocation EllipsisLoc, |
| Optional<unsigned> NumExpansions) { |
| // Create the pack expansion type and source-location information. |
| QualType Result = CheckPackExpansion(Pattern->getType(), |
| Pattern->getTypeLoc().getSourceRange(), |
| EllipsisLoc, NumExpansions); |
| if (Result.isNull()) |
| return nullptr; |
| |
| TypeLocBuilder TLB; |
| TLB.pushFullCopy(Pattern->getTypeLoc()); |
| PackExpansionTypeLoc TL = TLB.push<PackExpansionTypeLoc>(Result); |
| TL.setEllipsisLoc(EllipsisLoc); |
| |
| return TLB.getTypeSourceInfo(Context, Result); |
| } |
| |
| QualType Sema::CheckPackExpansion(QualType Pattern, SourceRange PatternRange, |
| SourceLocation EllipsisLoc, |
| Optional<unsigned> NumExpansions) { |
| // C++11 [temp.variadic]p5: |
| // The pattern of a pack expansion shall name one or more |
| // parameter packs that are not expanded by a nested pack |
| // expansion. |
| // |
| // A pattern containing a deduced type can't occur "naturally" but arises in |
| // the desugaring of an init-capture pack. |
| if (!Pattern->containsUnexpandedParameterPack() && |
| !Pattern->getContainedDeducedType()) { |
| Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs) |
| << PatternRange; |
| return QualType(); |
| } |
| |
| return Context.getPackExpansionType(Pattern, NumExpansions); |
| } |
| |
| ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) { |
| return CheckPackExpansion(Pattern, EllipsisLoc, None); |
| } |
| |
| ExprResult Sema::CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc, |
| Optional<unsigned> NumExpansions) { |
| if (!Pattern) |
| return ExprError(); |
| |
| // C++0x [temp.variadic]p5: |
| // The pattern of a pack expansion shall name one or more |
| // parameter packs that are not expanded by a nested pack |
| // expansion. |
| if (!Pattern->containsUnexpandedParameterPack()) { |
| Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs) |
| << Pattern->getSourceRange(); |
| CorrectDelayedTyposInExpr(Pattern); |
| return ExprError(); |
| } |
| |
| // Create the pack expansion expression and source-location information. |
| return new (Context) |
| PackExpansionExpr(Context.DependentTy, Pattern, EllipsisLoc, NumExpansions); |
| } |
| |
| bool Sema::CheckParameterPacksForExpansion( |
| SourceLocation EllipsisLoc, SourceRange PatternRange, |
| ArrayRef<UnexpandedParameterPack> Unexpanded, |
| const MultiLevelTemplateArgumentList &TemplateArgs, bool &ShouldExpand, |
| bool &RetainExpansion, Optional<unsigned> &NumExpansions) { |
| ShouldExpand = true; |
| RetainExpansion = false; |
| std::pair<IdentifierInfo *, SourceLocation> FirstPack; |
| bool HaveFirstPack = false; |
| Optional<unsigned> NumPartialExpansions; |
| SourceLocation PartiallySubstitutedPackLoc; |
| |
| for (ArrayRef<UnexpandedParameterPack>::iterator i = Unexpanded.begin(), |
| end = Unexpanded.end(); |
| i != end; ++i) { |
| // Compute the depth and index for this parameter pack. |
| unsigned Depth = 0, Index = 0; |
| IdentifierInfo *Name; |
| bool IsVarDeclPack = false; |
| |
| if (const TemplateTypeParmType *TTP |
| = i->first.dyn_cast<const TemplateTypeParmType *>()) { |
| Depth = TTP->getDepth(); |
| Index = TTP->getIndex(); |
| Name = TTP->getIdentifier(); |
| } else { |
| NamedDecl *ND = i->first.get<NamedDecl *>(); |
| if (isa<VarDecl>(ND)) |
| IsVarDeclPack = true; |
| else |
| std::tie(Depth, Index) = getDepthAndIndex(ND); |
| |
| Name = ND->getIdentifier(); |
| } |
| |
| // Determine the size of this argument pack. |
| unsigned NewPackSize; |
| if (IsVarDeclPack) { |
| // Figure out whether we're instantiating to an argument pack or not. |
| typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack; |
| |
| llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation |
| = CurrentInstantiationScope->findInstantiationOf( |
| i->first.get<NamedDecl *>()); |
| if (Instantiation->is<DeclArgumentPack *>()) { |
| // We could expand this function parameter pack. |
| NewPackSize = Instantiation->get<DeclArgumentPack *>()->size(); |
| } else { |
| // We can't expand this function parameter pack, so we can't expand |
| // the pack expansion. |
| ShouldExpand = false; |
| continue; |
| } |
| } else { |
| // If we don't have a template argument at this depth/index, then we |
| // cannot expand the pack expansion. Make a note of this, but we still |
| // want to check any parameter packs we *do* have arguments for. |
| if (Depth >= TemplateArgs.getNumLevels() || |
| !TemplateArgs.hasTemplateArgument(Depth, Index)) { |
| ShouldExpand = false; |
| continue; |
| } |
| |
| // Determine the size of the argument pack. |
| NewPackSize = TemplateArgs(Depth, Index).pack_size(); |
| } |
| |
| // C++0x [temp.arg.explicit]p9: |
| // Template argument deduction can extend the sequence of template |
| // arguments corresponding to a template parameter pack, even when the |
| // sequence contains explicitly specified template arguments. |
| if (!IsVarDeclPack && CurrentInstantiationScope) { |
| if (NamedDecl *PartialPack |
| = CurrentInstantiationScope->getPartiallySubstitutedPack()){ |
| unsigned PartialDepth, PartialIndex; |
| std::tie(PartialDepth, PartialIndex) = getDepthAndIndex(PartialPack); |
| if (PartialDepth == Depth && PartialIndex == Index) { |
| RetainExpansion = true; |
| // We don't actually know the new pack size yet. |
| NumPartialExpansions = NewPackSize; |
| PartiallySubstitutedPackLoc = i->second; |
| continue; |
| } |
| } |
| } |
| |
| if (!NumExpansions) { |
| // The is the first pack we've seen for which we have an argument. |
| // Record it. |
| NumExpansions = NewPackSize; |
| FirstPack.first = Name; |
| FirstPack.second = i->second; |
| HaveFirstPack = true; |
| continue; |
| } |
| |
| if (NewPackSize != *NumExpansions) { |
| // C++0x [temp.variadic]p5: |
| // All of the parameter packs expanded by a pack expansion shall have |
| // the same number of arguments specified. |
| if (HaveFirstPack) |
| Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict) |
| << FirstPack.first << Name << *NumExpansions << NewPackSize |
| << SourceRange(FirstPack.second) << SourceRange(i->second); |
| else |
| Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict_multilevel) |
| << Name << *NumExpansions << NewPackSize |
| << SourceRange(i->second); |
| return true; |
| } |
| } |
| |
| // If we're performing a partial expansion but we also have a full expansion, |
| // expand to the number of common arguments. For example, given: |
| // |
| // template<typename ...T> struct A { |
| // template<typename ...U> void f(pair<T, U>...); |
| // }; |
| // |
| // ... a call to 'A<int, int>().f<int>' should expand the pack once and |
| // retain an expansion. |
| if (NumPartialExpansions) { |
| if (NumExpansions && *NumExpansions < *NumPartialExpansions) { |
| NamedDecl *PartialPack = |
| CurrentInstantiationScope->getPartiallySubstitutedPack(); |
| Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict_partial) |
| << PartialPack << *NumPartialExpansions << *NumExpansions |
| << SourceRange(PartiallySubstitutedPackLoc); |
| return true; |
| } |
| |
| NumExpansions = NumPartialExpansions; |
| } |
| |
| return false; |
| } |
| |
| Optional<unsigned> Sema::getNumArgumentsInExpansion(QualType T, |
| const MultiLevelTemplateArgumentList &TemplateArgs) { |
| QualType Pattern = cast<PackExpansionType>(T)->getPattern(); |
| SmallVector<UnexpandedParameterPack, 2> Unexpanded; |
| CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(Pattern); |
| |
| Optional<unsigned> Result; |
| for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { |
| // Compute the depth and index for this parameter pack. |
| unsigned Depth; |
| unsigned Index; |
| |
| if (const TemplateTypeParmType *TTP |
| = Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>()) { |
| Depth = TTP->getDepth(); |
| Index = TTP->getIndex(); |
| } else { |
| NamedDecl *ND = Unexpanded[I].first.get<NamedDecl *>(); |
| if (isa<VarDecl>(ND)) { |
| // Function parameter pack or init-capture pack. |
| typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack; |
| |
| llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation |
| = CurrentInstantiationScope->findInstantiationOf( |
| Unexpanded[I].first.get<NamedDecl *>()); |
| if (Instantiation->is<Decl*>()) |
| // The pattern refers to an unexpanded pack. We're not ready to expand |
| // this pack yet. |
| return None; |
| |
| unsigned Size = Instantiation->get<DeclArgumentPack *>()->size(); |
| assert((!Result || *Result == Size) && "inconsistent pack sizes"); |
| Result = Size; |
| continue; |
| } |
| |
| std::tie(Depth, Index) = getDepthAndIndex(ND); |
| } |
| if (Depth >= TemplateArgs.getNumLevels() || |
| !TemplateArgs.hasTemplateArgument(Depth, Index)) |
| // The pattern refers to an unknown template argument. We're not ready to |
| // expand this pack yet. |
| return None; |
| |
| // Determine the size of the argument pack. |
| unsigned Size = TemplateArgs(Depth, Index).pack_size(); |
| assert((!Result || *Result == Size) && "inconsistent pack sizes"); |
| Result = Size; |
| } |
| |
| return Result; |
| } |
| |
| bool Sema::containsUnexpandedParameterPacks(Declarator &D) { |
| const DeclSpec &DS = D.getDeclSpec(); |
| switch (DS.getTypeSpecType()) { |
| case TST_typename: |
| case TST_typeofType: |
| case TST_underlyingType: |
| case TST_atomic: { |
| QualType T = DS.getRepAsType().get(); |
| if (!T.isNull() && T->containsUnexpandedParameterPack()) |
| return true; |
| break; |
| } |
| |
| case TST_typeofExpr: |
| case TST_decltype: |
| if (DS.getRepAsExpr() && |
| DS.getRepAsExpr()->containsUnexpandedParameterPack()) |
| return true; |
| break; |
| |
| case TST_unspecified: |
| case TST_void: |
| case TST_char: |
| case TST_wchar: |
| case TST_char8: |
| case TST_char16: |
| case TST_char32: |
| case TST_int: |
| case TST_int128: |
| case TST_half: |
| case TST_float: |
| case TST_double: |
| case TST_Accum: |
| case TST_Fract: |
| case TST_Float16: |
| case TST_float128: |
| case TST_bool: |
| case TST_decimal32: |
| case TST_decimal64: |
| case TST_decimal128: |
| case TST_enum: |
| case TST_union: |
| case TST_struct: |
| case TST_interface: |
| case TST_class: |
| case TST_auto: |
| case TST_auto_type: |
| case TST_decltype_auto: |
| #define GENERIC_IMAGE_TYPE(ImgType, Id) case TST_##ImgType##_t: |
| #include "clang/Basic/OpenCLImageTypes.def" |
| case TST_unknown_anytype: |
| case TST_error: |
| break; |
| } |
| |
| for (unsigned I = 0, N = D.getNumTypeObjects(); I != N; ++I) { |
| const DeclaratorChunk &Chunk = D.getTypeObject(I); |
| switch (Chunk.Kind) { |
| case DeclaratorChunk::Pointer: |
| case DeclaratorChunk::Reference: |
| case DeclaratorChunk::Paren: |
| case DeclaratorChunk::Pipe: |
| case DeclaratorChunk::BlockPointer: |
| // These declarator chunks cannot contain any parameter packs. |
| break; |
| |
| case DeclaratorChunk::Array: |
| if (Chunk.Arr.NumElts && |
| Chunk.Arr.NumElts->containsUnexpandedParameterPack()) |
| return true; |
| break; |
| case DeclaratorChunk::Function: |
| for (unsigned i = 0, e = Chunk.Fun.NumParams; i != e; ++i) { |
| ParmVarDecl *Param = cast<ParmVarDecl>(Chunk.Fun.Params[i].Param); |
| QualType ParamTy = Param->getType(); |
| assert(!ParamTy.isNull() && "Couldn't parse type?"); |
| if (ParamTy->containsUnexpandedParameterPack()) return true; |
| } |
| |
| if (Chunk.Fun.getExceptionSpecType() == EST_Dynamic) { |
| for (unsigned i = 0; i != Chunk.Fun.getNumExceptions(); ++i) { |
| if (Chunk.Fun.Exceptions[i] |
| .Ty.get() |
| ->containsUnexpandedParameterPack()) |
| return true; |
| } |
| } else if (isComputedNoexcept(Chunk.Fun.getExceptionSpecType()) && |
| Chunk.Fun.NoexceptExpr->containsUnexpandedParameterPack()) |
| return true; |
| |
| if (Chunk.Fun.hasTrailingReturnType()) { |
| QualType T = Chunk.Fun.getTrailingReturnType().get(); |
| if (!T.isNull() && T->containsUnexpandedParameterPack()) |
| return true; |
| } |
| break; |
| |
| case DeclaratorChunk::MemberPointer: |
| if (Chunk.Mem.Scope().getScopeRep() && |
| Chunk.Mem.Scope().getScopeRep()->containsUnexpandedParameterPack()) |
| return true; |
| break; |
| } |
| } |
| |
| return false; |
| } |
| |
| namespace { |
| |
| // Callback to only accept typo corrections that refer to parameter packs. |
| class ParameterPackValidatorCCC final : public CorrectionCandidateCallback { |
| public: |
| bool ValidateCandidate(const TypoCorrection &candidate) override { |
| NamedDecl *ND = candidate.getCorrectionDecl(); |
| return ND && ND->isParameterPack(); |
| } |
| |
| std::unique_ptr<CorrectionCandidateCallback> clone() override { |
| return std::make_unique<ParameterPackValidatorCCC>(*this); |
| } |
| }; |
| |
| } |
| |
| /// Called when an expression computing the size of a parameter pack |
| /// is parsed. |
| /// |
| /// \code |
| /// template<typename ...Types> struct count { |
| /// static const unsigned value = sizeof...(Types); |
| /// }; |
| /// \endcode |
| /// |
| // |
| /// \param OpLoc The location of the "sizeof" keyword. |
| /// \param Name The name of the parameter pack whose size will be determined. |
| /// \param NameLoc The source location of the name of the parameter pack. |
| /// \param RParenLoc The location of the closing parentheses. |
| ExprResult Sema::ActOnSizeofParameterPackExpr(Scope *S, |
| SourceLocation OpLoc, |
| IdentifierInfo &Name, |
| SourceLocation NameLoc, |
| SourceLocation RParenLoc) { |
| // C++0x [expr.sizeof]p5: |
| // The identifier in a sizeof... expression shall name a parameter pack. |
| LookupResult R(*this, &Name, NameLoc, LookupOrdinaryName); |
| LookupName(R, S); |
| |
| NamedDecl *ParameterPack = nullptr; |
| switch (R.getResultKind()) { |
| case LookupResult::Found: |
| ParameterPack = R.getFoundDecl(); |
| break; |
| |
| case LookupResult::NotFound: |
| case LookupResult::NotFoundInCurrentInstantiation: { |
| ParameterPackValidatorCCC CCC{}; |
| if (TypoCorrection Corrected = |
| CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr, |
| CCC, CTK_ErrorRecovery)) { |
| diagnoseTypo(Corrected, |
| PDiag(diag::err_sizeof_pack_no_pack_name_suggest) << &Name, |
| PDiag(diag::note_parameter_pack_here)); |
| ParameterPack = Corrected.getCorrectionDecl(); |
| } |
| break; |
| } |
| case LookupResult::FoundOverloaded: |
| case LookupResult::FoundUnresolvedValue: |
| break; |
| |
| case LookupResult::Ambiguous: |
| DiagnoseAmbiguousLookup(R); |
| return ExprError(); |
| } |
| |
| if (!ParameterPack || !ParameterPack->isParameterPack()) { |
| Diag(NameLoc, diag::err_sizeof_pack_no_pack_name) |
| << &Name; |
| return ExprError(); |
| } |
| |
| MarkAnyDeclReferenced(OpLoc, ParameterPack, true); |
| |
| return SizeOfPackExpr::Create(Context, OpLoc, ParameterPack, NameLoc, |
| RParenLoc); |
| } |
| |
| TemplateArgumentLoc |
| Sema::getTemplateArgumentPackExpansionPattern( |
| TemplateArgumentLoc OrigLoc, |
| SourceLocation &Ellipsis, Optional<unsigned> &NumExpansions) const { |
| const TemplateArgument &Argument = OrigLoc.getArgument(); |
| assert(Argument.isPackExpansion()); |
| switch (Argument.getKind()) { |
| case TemplateArgument::Type: { |
| // FIXME: We shouldn't ever have to worry about missing |
| // type-source info! |
| TypeSourceInfo *ExpansionTSInfo = OrigLoc.getTypeSourceInfo(); |
| if (!ExpansionTSInfo) |
| ExpansionTSInfo = Context.getTrivialTypeSourceInfo(Argument.getAsType(), |
| Ellipsis); |
| PackExpansionTypeLoc Expansion = |
| ExpansionTSInfo->getTypeLoc().castAs<PackExpansionTypeLoc>(); |
| Ellipsis = Expansion.getEllipsisLoc(); |
| |
| TypeLoc Pattern = Expansion.getPatternLoc(); |
| NumExpansions = Expansion.getTypePtr()->getNumExpansions(); |
| |
| // We need to copy the TypeLoc because TemplateArgumentLocs store a |
| // TypeSourceInfo. |
| // FIXME: Find some way to avoid the copy? |
| TypeLocBuilder TLB; |
| TLB.pushFullCopy(Pattern); |
| TypeSourceInfo *PatternTSInfo = |
| TLB.getTypeSourceInfo(Context, Pattern.getType()); |
| return TemplateArgumentLoc(TemplateArgument(Pattern.getType()), |
| PatternTSInfo); |
| } |
| |
| case TemplateArgument::Expression: { |
| PackExpansionExpr *Expansion |
| = cast<PackExpansionExpr>(Argument.getAsExpr()); |
| Expr *Pattern = Expansion->getPattern(); |
| Ellipsis = Expansion->getEllipsisLoc(); |
| NumExpansions = Expansion->getNumExpansions(); |
| return TemplateArgumentLoc(Pattern, Pattern); |
| } |
| |
| case TemplateArgument::TemplateExpansion: |
| Ellipsis = OrigLoc.getTemplateEllipsisLoc(); |
| NumExpansions = Argument.getNumTemplateExpansions(); |
| return TemplateArgumentLoc(Argument.getPackExpansionPattern(), |
| OrigLoc.getTemplateQualifierLoc(), |
| OrigLoc.getTemplateNameLoc()); |
| |
| case TemplateArgument::Declaration: |
| case TemplateArgument::NullPtr: |
| case TemplateArgument::Template: |
| case TemplateArgument::Integral: |
| case TemplateArgument::Pack: |
| case TemplateArgument::Null: |
| return TemplateArgumentLoc(); |
| } |
| |
| llvm_unreachable("Invalid TemplateArgument Kind!"); |
| } |
| |
| Optional<unsigned> Sema::getFullyPackExpandedSize(TemplateArgument Arg) { |
| assert(Arg.containsUnexpandedParameterPack()); |
| |
| // If this is a substituted pack, grab that pack. If not, we don't know |
| // the size yet. |
| // FIXME: We could find a size in more cases by looking for a substituted |
| // pack anywhere within this argument, but that's not necessary in the common |
| // case for 'sizeof...(A)' handling. |
| TemplateArgument Pack; |
| switch (Arg.getKind()) { |
| case TemplateArgument::Type: |
| if (auto *Subst = Arg.getAsType()->getAs<SubstTemplateTypeParmPackType>()) |
| Pack = Subst->getArgumentPack(); |
| else |
| return None; |
| break; |
| |
| case TemplateArgument::Expression: |
| if (auto *Subst = |
| dyn_cast<SubstNonTypeTemplateParmPackExpr>(Arg.getAsExpr())) |
| Pack = Subst->getArgumentPack(); |
| else if (auto *Subst = dyn_cast<FunctionParmPackExpr>(Arg.getAsExpr())) { |
| for (VarDecl *PD : *Subst) |
| if (PD->isParameterPack()) |
| return None; |
| return Subst->getNumExpansions(); |
| } else |
| return None; |
| break; |
| |
| case TemplateArgument::Template: |
| if (SubstTemplateTemplateParmPackStorage *Subst = |
| Arg.getAsTemplate().getAsSubstTemplateTemplateParmPack()) |
| Pack = Subst->getArgumentPack(); |
| else |
| return None; |
| break; |
| |
| case TemplateArgument::Declaration: |
| case TemplateArgument::NullPtr: |
| case TemplateArgument::TemplateExpansion: |
| case TemplateArgument::Integral: |
| case TemplateArgument::Pack: |
| case TemplateArgument::Null: |
| return None; |
| } |
| |
| // Check that no argument in the pack is itself a pack expansion. |
| for (TemplateArgument Elem : Pack.pack_elements()) { |
| // There's no point recursing in this case; we would have already |
| // expanded this pack expansion into the enclosing pack if we could. |
| if (Elem.isPackExpansion()) |
| return None; |
| } |
| return Pack.pack_size(); |
| } |
| |
| static void CheckFoldOperand(Sema &S, Expr *E) { |
| if (!E) |
| return; |
| |
| E = E->IgnoreImpCasts(); |
| auto *OCE = dyn_cast<CXXOperatorCallExpr>(E); |
| if ((OCE && OCE->isInfixBinaryOp()) || isa<BinaryOperator>(E) || |
| isa<AbstractConditionalOperator>(E)) { |
| S.Diag(E->getExprLoc(), diag::err_fold_expression_bad_operand) |
| << E->getSourceRange() |
| << FixItHint::CreateInsertion(E->getBeginLoc(), "(") |
| << FixItHint::CreateInsertion(E->getEndLoc(), ")"); |
| } |
| } |
| |
| ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS, |
| tok::TokenKind Operator, |
| SourceLocation EllipsisLoc, Expr *RHS, |
| SourceLocation RParenLoc) { |
| // LHS and RHS must be cast-expressions. We allow an arbitrary expression |
| // in the parser and reduce down to just cast-expressions here. |
| CheckFoldOperand(*this, LHS); |
| CheckFoldOperand(*this, RHS); |
| |
| auto DiscardOperands = [&] { |
| CorrectDelayedTyposInExpr(LHS); |
| CorrectDelayedTyposInExpr(RHS); |
| }; |
| |
| // [expr.prim.fold]p3: |
| // In a binary fold, op1 and op2 shall be the same fold-operator, and |
| // either e1 shall contain an unexpanded parameter pack or e2 shall contain |
| // an unexpanded parameter pack, but not both. |
| if (LHS && RHS && |
| LHS->containsUnexpandedParameterPack() == |
| RHS->containsUnexpandedParameterPack()) { |
| DiscardOperands(); |
| return Diag(EllipsisLoc, |
| LHS->containsUnexpandedParameterPack() |
| ? diag::err_fold_expression_packs_both_sides |
| : diag::err_pack_expansion_without_parameter_packs) |
| << LHS->getSourceRange() << RHS->getSourceRange(); |
| } |
| |
| // [expr.prim.fold]p2: |
| // In a unary fold, the cast-expression shall contain an unexpanded |
| // parameter pack. |
| if (!LHS || !RHS) { |
| Expr *Pack = LHS ? LHS : RHS; |
| assert(Pack && "fold expression with neither LHS nor RHS"); |
| DiscardOperands(); |
| if (!Pack->containsUnexpandedParameterPack()) |
| return Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs) |
| << Pack->getSourceRange(); |
| } |
| |
| BinaryOperatorKind Opc = ConvertTokenKindToBinaryOpcode(Operator); |
| return BuildCXXFoldExpr(LParenLoc, LHS, Opc, EllipsisLoc, RHS, RParenLoc, |
| None); |
| } |
| |
| ExprResult Sema::BuildCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS, |
| BinaryOperatorKind Operator, |
| SourceLocation EllipsisLoc, Expr *RHS, |
| SourceLocation RParenLoc, |
| Optional<unsigned> NumExpansions) { |
| return new (Context) CXXFoldExpr(Context.DependentTy, LParenLoc, LHS, |
| Operator, EllipsisLoc, RHS, RParenLoc, |
| NumExpansions); |
| } |
| |
| ExprResult Sema::BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc, |
| BinaryOperatorKind Operator) { |
| // [temp.variadic]p9: |
| // If N is zero for a unary fold-expression, the value of the expression is |
| // && -> true |
| // || -> false |
| // , -> void() |
| // if the operator is not listed [above], the instantiation is ill-formed. |
| // |
| // Note that we need to use something like int() here, not merely 0, to |
| // prevent the result from being a null pointer constant. |
| QualType ScalarType; |
| switch (Operator) { |
| case BO_LOr: |
| return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_false); |
| case BO_LAnd: |
| return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_true); |
| case BO_Comma: |
| ScalarType = Context.VoidTy; |
| break; |
| |
| default: |
| return Diag(EllipsisLoc, diag::err_fold_expression_empty) |
| << BinaryOperator::getOpcodeStr(Operator); |
| } |
| |
| return new (Context) CXXScalarValueInitExpr( |
| ScalarType, Context.getTrivialTypeSourceInfo(ScalarType, EllipsisLoc), |
| EllipsisLoc); |
| } |
