| //===- ExternalASTMerger.cpp - Merging External AST Interface ---*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the ExternalASTMerger, which vends a combination of |
| // ASTs from several different ASTContext/FileManager pairs |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/DeclCXX.h" |
| #include "clang/AST/DeclObjC.h" |
| #include "clang/AST/DeclTemplate.h" |
| #include "clang/AST/ExternalASTMerger.h" |
| |
| using namespace clang; |
| |
| namespace { |
| |
| template <typename T> struct Source { |
| T t; |
| Source(T t) : t(t) {} |
| operator T() { return t; } |
| template <typename U = T> U &get() { return t; } |
| template <typename U = T> const U &get() const { return t; } |
| template <typename U> operator Source<U>() { return Source<U>(t); } |
| }; |
| |
| typedef std::pair<Source<NamedDecl *>, ASTImporter *> Candidate; |
| |
| /// For the given DC, return the DC that is safe to perform lookups on. This is |
| /// the DC we actually want to work with most of the time. |
| const DeclContext *CanonicalizeDC(const DeclContext *DC) { |
| if (isa<LinkageSpecDecl>(DC)) |
| return DC->getRedeclContext(); |
| return DC; |
| } |
| |
| Source<const DeclContext *> |
| LookupSameContext(Source<TranslationUnitDecl *> SourceTU, const DeclContext *DC, |
| ASTImporter &ReverseImporter) { |
| DC = CanonicalizeDC(DC); |
| if (DC->isTranslationUnit()) { |
| return SourceTU; |
| } |
| Source<const DeclContext *> SourceParentDC = |
| LookupSameContext(SourceTU, DC->getParent(), ReverseImporter); |
| if (!SourceParentDC) { |
| // If we couldn't find the parent DC in this TranslationUnit, give up. |
| return nullptr; |
| } |
| auto *ND = cast<NamedDecl>(DC); |
| DeclarationName Name = ND->getDeclName(); |
| Source<DeclarationName> SourceName = ReverseImporter.Import(Name); |
| DeclContext::lookup_result SearchResult = |
| SourceParentDC.get()->lookup(SourceName.get()); |
| size_t SearchResultSize = SearchResult.size(); |
| if (SearchResultSize == 0 || SearchResultSize > 1) { |
| // There are two cases here. First, we might not find the name. |
| // We might also find multiple copies, in which case we have no |
| // guarantee that the one we wanted is the one we pick. (E.g., |
| // if we have two specializations of the same template it is |
| // very hard to determine which is the one you want.) |
| // |
| // The Origins map fixes this problem by allowing the origin to be |
| // explicitly recorded, so we trigger that recording by returning |
| // nothing (rather than a possibly-inaccurate guess) here. |
| return nullptr; |
| } else { |
| NamedDecl *SearchResultDecl = SearchResult[0]; |
| if (isa<DeclContext>(SearchResultDecl) && |
| SearchResultDecl->getKind() == DC->getDeclKind()) |
| return cast<DeclContext>(SearchResultDecl)->getPrimaryContext(); |
| return nullptr; // This type of lookup is unsupported |
| } |
| } |
| |
| /// A custom implementation of ASTImporter, for ExternalASTMerger's purposes. |
| /// |
| /// There are several modifications: |
| /// |
| /// - It enables lazy lookup (via the HasExternalLexicalStorage flag and a few |
| /// others), which instructs Clang to refer to ExternalASTMerger. Also, it |
| /// forces MinimalImport to true, which is necessary to make this work. |
| /// - It maintains a reverse importer for use with names. This allows lookup of |
| /// arbitrary names in the source context. |
| /// - It updates the ExternalASTMerger's origin map as needed whenever a |
| /// it sees a DeclContext. |
| class LazyASTImporter : public ASTImporter { |
| private: |
| ExternalASTMerger &Parent; |
| ASTImporter Reverse; |
| const ExternalASTMerger::OriginMap &FromOrigins; |
| |
| llvm::raw_ostream &logs() { return Parent.logs(); } |
| public: |
| LazyASTImporter(ExternalASTMerger &_Parent, ASTContext &ToContext, |
| FileManager &ToFileManager, ASTContext &FromContext, |
| FileManager &FromFileManager, |
| const ExternalASTMerger::OriginMap &_FromOrigins) |
| : ASTImporter(ToContext, ToFileManager, FromContext, FromFileManager, |
| /*MinimalImport=*/true), |
| Parent(_Parent), Reverse(FromContext, FromFileManager, ToContext, |
| ToFileManager, /*MinimalImport=*/true), FromOrigins(_FromOrigins) {} |
| |
| /// Whenever a DeclContext is imported, ensure that ExternalASTSource's origin |
| /// map is kept up to date. Also set the appropriate flags. |
| Decl *Imported(Decl *From, Decl *To) override { |
| if (auto *ToDC = dyn_cast<DeclContext>(To)) { |
| const bool LoggingEnabled = Parent.LoggingEnabled(); |
| if (LoggingEnabled) |
| logs() << "(ExternalASTMerger*)" << (void*)&Parent |
| << " imported (DeclContext*)" << (void*)ToDC |
| << ", (ASTContext*)" << (void*)&getToContext() |
| << " from (DeclContext*)" << (void*)llvm::cast<DeclContext>(From) |
| << ", (ASTContext*)" << (void*)&getFromContext() |
| << "\n"; |
| Source<DeclContext *> FromDC( |
| cast<DeclContext>(From)->getPrimaryContext()); |
| if (FromOrigins.count(FromDC) && |
| Parent.HasImporterForOrigin(*FromOrigins.at(FromDC).AST)) { |
| if (LoggingEnabled) |
| logs() << "(ExternalASTMerger*)" << (void*)&Parent |
| << " forced origin (DeclContext*)" |
| << (void*)FromOrigins.at(FromDC).DC |
| << ", (ASTContext*)" |
| << (void*)FromOrigins.at(FromDC).AST |
| << "\n"; |
| Parent.ForceRecordOrigin(ToDC, FromOrigins.at(FromDC)); |
| } else { |
| if (LoggingEnabled) |
| logs() << "(ExternalASTMerger*)" << (void*)&Parent |
| << " maybe recording origin (DeclContext*)" << (void*)FromDC |
| << ", (ASTContext*)" << (void*)&getFromContext() |
| << "\n"; |
| Parent.MaybeRecordOrigin(ToDC, {FromDC, &getFromContext()}); |
| } |
| } |
| if (auto *ToTag = dyn_cast<TagDecl>(To)) { |
| ToTag->setHasExternalLexicalStorage(); |
| ToTag->setMustBuildLookupTable(); |
| assert(Parent.CanComplete(ToTag)); |
| } else if (auto *ToNamespace = dyn_cast<NamespaceDecl>(To)) { |
| ToNamespace->setHasExternalVisibleStorage(); |
| assert(Parent.CanComplete(ToNamespace)); |
| } else if (auto *ToContainer = dyn_cast<ObjCContainerDecl>(To)) { |
| ToContainer->setHasExternalLexicalStorage(); |
| ToContainer->setMustBuildLookupTable(); |
| assert(Parent.CanComplete(ToContainer)); |
| } |
| return To; |
| } |
| ASTImporter &GetReverse() { return Reverse; } |
| }; |
| |
| bool HasDeclOfSameType(llvm::ArrayRef<Candidate> Decls, const Candidate &C) { |
| if (isa<FunctionDecl>(C.first.get())) |
| return false; |
| return llvm::any_of(Decls, [&](const Candidate &D) { |
| return C.first.get()->getKind() == D.first.get()->getKind(); |
| }); |
| } |
| |
| } // end namespace |
| |
| ASTImporter &ExternalASTMerger::ImporterForOrigin(ASTContext &OriginContext) { |
| for (const std::unique_ptr<ASTImporter> &I : Importers) |
| if (&I->getFromContext() == &OriginContext) |
| return *I; |
| llvm_unreachable("We should have an importer for this origin!"); |
| } |
| |
| namespace { |
| LazyASTImporter &LazyImporterForOrigin(ExternalASTMerger &Merger, |
| ASTContext &OriginContext) { |
| return static_cast<LazyASTImporter &>( |
| Merger.ImporterForOrigin(OriginContext)); |
| } |
| } |
| |
| bool ExternalASTMerger::HasImporterForOrigin(ASTContext &OriginContext) { |
| for (const std::unique_ptr<ASTImporter> &I : Importers) |
| if (&I->getFromContext() == &OriginContext) |
| return true; |
| return false; |
| } |
| |
| template <typename CallbackType> |
| void ExternalASTMerger::ForEachMatchingDC(const DeclContext *DC, |
| CallbackType Callback) { |
| if (Origins.count(DC)) { |
| ExternalASTMerger::DCOrigin Origin = Origins[DC]; |
| LazyASTImporter &Importer = LazyImporterForOrigin(*this, *Origin.AST); |
| Callback(Importer, Importer.GetReverse(), Origin.DC); |
| } else { |
| bool DidCallback = false; |
| for (const std::unique_ptr<ASTImporter> &Importer : Importers) { |
| Source<TranslationUnitDecl *> SourceTU = |
| Importer->getFromContext().getTranslationUnitDecl(); |
| ASTImporter &Reverse = |
| static_cast<LazyASTImporter *>(Importer.get())->GetReverse(); |
| if (auto SourceDC = LookupSameContext(SourceTU, DC, Reverse)) { |
| DidCallback = true; |
| if (Callback(*Importer, Reverse, SourceDC)) |
| break; |
| } |
| } |
| if (!DidCallback && LoggingEnabled()) |
| logs() << "(ExternalASTMerger*)" << (void*)this |
| << " asserting for (DeclContext*)" << (const void*)DC |
| << ", (ASTContext*)" << (void*)&Target.AST |
| << "\n"; |
| assert(DidCallback && "Couldn't find a source context matching our DC"); |
| } |
| } |
| |
| void ExternalASTMerger::CompleteType(TagDecl *Tag) { |
| assert(Tag->hasExternalLexicalStorage()); |
| ForEachMatchingDC(Tag, [&](ASTImporter &Forward, ASTImporter &Reverse, |
| Source<const DeclContext *> SourceDC) -> bool { |
| auto *SourceTag = const_cast<TagDecl *>(cast<TagDecl>(SourceDC.get())); |
| if (SourceTag->hasExternalLexicalStorage()) |
| SourceTag->getASTContext().getExternalSource()->CompleteType(SourceTag); |
| if (!SourceTag->getDefinition()) |
| return false; |
| Forward.MapImported(SourceTag, Tag); |
| Forward.ImportDefinition(SourceTag); |
| Tag->setCompleteDefinition(SourceTag->isCompleteDefinition()); |
| return true; |
| }); |
| } |
| |
| void ExternalASTMerger::CompleteType(ObjCInterfaceDecl *Interface) { |
| assert(Interface->hasExternalLexicalStorage()); |
| ForEachMatchingDC( |
| Interface, [&](ASTImporter &Forward, ASTImporter &Reverse, |
| Source<const DeclContext *> SourceDC) -> bool { |
| auto *SourceInterface = const_cast<ObjCInterfaceDecl *>( |
| cast<ObjCInterfaceDecl>(SourceDC.get())); |
| if (SourceInterface->hasExternalLexicalStorage()) |
| SourceInterface->getASTContext().getExternalSource()->CompleteType( |
| SourceInterface); |
| if (!SourceInterface->getDefinition()) |
| return false; |
| Forward.MapImported(SourceInterface, Interface); |
| Forward.ImportDefinition(SourceInterface); |
| return true; |
| }); |
| } |
| |
| bool ExternalASTMerger::CanComplete(DeclContext *Interface) { |
| assert(Interface->hasExternalLexicalStorage() || |
| Interface->hasExternalVisibleStorage()); |
| bool FoundMatchingDC = false; |
| ForEachMatchingDC(Interface, |
| [&](ASTImporter &Forward, ASTImporter &Reverse, |
| Source<const DeclContext *> SourceDC) -> bool { |
| FoundMatchingDC = true; |
| return true; |
| }); |
| return FoundMatchingDC; |
| } |
| |
| namespace { |
| bool IsSameDC(const DeclContext *D1, const DeclContext *D2) { |
| if (isa<ObjCContainerDecl>(D1) && isa<ObjCContainerDecl>(D2)) |
| return true; // There are many cases where Objective-C is ambiguous. |
| if (auto *T1 = dyn_cast<TagDecl>(D1)) |
| if (auto *T2 = dyn_cast<TagDecl>(D2)) |
| if (T1->getFirstDecl() == T2->getFirstDecl()) |
| return true; |
| return D1 == D2 || D1 == CanonicalizeDC(D2); |
| } |
| } |
| |
| void ExternalASTMerger::MaybeRecordOrigin(const DeclContext *ToDC, |
| DCOrigin Origin) { |
| LazyASTImporter &Importer = LazyImporterForOrigin(*this, *Origin.AST); |
| ASTImporter &Reverse = Importer.GetReverse(); |
| Source<const DeclContext *> FoundFromDC = |
| LookupSameContext(Origin.AST->getTranslationUnitDecl(), ToDC, Reverse); |
| const bool DoRecord = !FoundFromDC || !IsSameDC(FoundFromDC.get(), Origin.DC); |
| if (DoRecord) |
| RecordOriginImpl(ToDC, Origin, Importer); |
| if (LoggingEnabled()) |
| logs() << "(ExternalASTMerger*)" << (void*)this |
| << (DoRecord ? " decided " : " decided NOT") |
| << " to record origin (DeclContext*)" << (void*)Origin.DC |
| << ", (ASTContext*)" << (void*)&Origin.AST |
| << "\n"; |
| } |
| |
| void ExternalASTMerger::ForceRecordOrigin(const DeclContext *ToDC, |
| DCOrigin Origin) { |
| RecordOriginImpl(ToDC, Origin, ImporterForOrigin(*Origin.AST)); |
| } |
| |
| void ExternalASTMerger::RecordOriginImpl(const DeclContext *ToDC, DCOrigin Origin, |
| ASTImporter &Importer) { |
| Origins[ToDC] = Origin; |
| Importer.ASTImporter::MapImported(cast<Decl>(Origin.DC), const_cast<Decl*>(cast<Decl>(ToDC))); |
| } |
| |
| ExternalASTMerger::ExternalASTMerger(const ImporterTarget &Target, |
| llvm::ArrayRef<ImporterSource> Sources) : LogStream(&llvm::nulls()), Target(Target) { |
| AddSources(Sources); |
| } |
| |
| void ExternalASTMerger::AddSources(llvm::ArrayRef<ImporterSource> Sources) { |
| for (const ImporterSource &S : Sources) { |
| assert(&S.AST != &Target.AST); |
| Importers.push_back(llvm::make_unique<LazyASTImporter>( |
| *this, Target.AST, Target.FM, S.AST, S.FM, S.OM)); |
| } |
| } |
| |
| void ExternalASTMerger::RemoveSources(llvm::ArrayRef<ImporterSource> Sources) { |
| if (LoggingEnabled()) |
| for (const ImporterSource &S : Sources) |
| logs() << "(ExternalASTMerger*)" << (void*)this |
| << " removing source (ASTContext*)" << (void*)&S.AST |
| << "\n"; |
| Importers.erase( |
| std::remove_if(Importers.begin(), Importers.end(), |
| [&Sources](std::unique_ptr<ASTImporter> &Importer) -> bool { |
| for (const ImporterSource &S : Sources) { |
| if (&Importer->getFromContext() == &S.AST) |
| return true; |
| } |
| return false; |
| }), |
| Importers.end()); |
| for (OriginMap::iterator OI = Origins.begin(), OE = Origins.end(); OI != OE; ) { |
| std::pair<const DeclContext *, DCOrigin> Origin = *OI; |
| bool Erase = false; |
| for (const ImporterSource &S : Sources) { |
| if (&S.AST == Origin.second.AST) { |
| Erase = true; |
| break; |
| } |
| } |
| if (Erase) |
| OI = Origins.erase(OI); |
| else |
| ++OI; |
| } |
| } |
| |
| template <typename DeclTy> |
| static bool importSpecializations(DeclTy *D, ASTImporter *Importer) { |
| for (auto *Spec : D->specializations()) |
| if (!Importer->Import(Spec)) |
| return true; |
| return false; |
| } |
| |
| /// Imports specializations from template declarations that can be specialized. |
| static bool importSpecializationsIfNeeded(Decl *D, ASTImporter *Importer) { |
| if (!isa<TemplateDecl>(D)) |
| return false; |
| if (auto *FunctionTD = dyn_cast<FunctionTemplateDecl>(D)) |
| return importSpecializations(FunctionTD, Importer); |
| else if (auto *ClassTD = dyn_cast<ClassTemplateDecl>(D)) |
| return importSpecializations(ClassTD, Importer); |
| else if (auto *VarTD = dyn_cast<VarTemplateDecl>(D)) |
| return importSpecializations(VarTD, Importer); |
| return false; |
| } |
| |
| bool ExternalASTMerger::FindExternalVisibleDeclsByName(const DeclContext *DC, |
| DeclarationName Name) { |
| llvm::SmallVector<NamedDecl *, 1> Decls; |
| llvm::SmallVector<Candidate, 4> Candidates; |
| |
| auto FilterFoundDecl = [&Candidates](const Candidate &C) { |
| if (!HasDeclOfSameType(Candidates, C)) |
| Candidates.push_back(C); |
| }; |
| |
| ForEachMatchingDC(DC, [&](ASTImporter &Forward, ASTImporter &Reverse, |
| Source<const DeclContext *> SourceDC) -> bool { |
| DeclarationName FromName = Reverse.Import(Name); |
| DeclContextLookupResult Result = SourceDC.get()->lookup(FromName); |
| for (NamedDecl *FromD : Result) { |
| FilterFoundDecl(std::make_pair(FromD, &Forward)); |
| } |
| return false; |
| }); |
| |
| if (Candidates.empty()) |
| return false; |
| |
| Decls.reserve(Candidates.size()); |
| for (const Candidate &C : Candidates) { |
| Decl *LookupRes = C.first.get(); |
| ASTImporter *Importer = C.second; |
| NamedDecl *ND = cast_or_null<NamedDecl>(Importer->Import(LookupRes)); |
| assert(ND); |
| // If we don't import specialization, they are not available via lookup |
| // because the lookup result is imported TemplateDecl and it does not |
| // reference its specializations until they are imported explicitly. |
| bool IsSpecImportFailed = |
| importSpecializationsIfNeeded(LookupRes, Importer); |
| assert(!IsSpecImportFailed); |
| (void)IsSpecImportFailed; |
| Decls.push_back(ND); |
| } |
| SetExternalVisibleDeclsForName(DC, Name, Decls); |
| return true; |
| } |
| |
| void ExternalASTMerger::FindExternalLexicalDecls( |
| const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant, |
| SmallVectorImpl<Decl *> &Result) { |
| ForEachMatchingDC(DC, [&](ASTImporter &Forward, ASTImporter &Reverse, |
| Source<const DeclContext *> SourceDC) -> bool { |
| for (const Decl *SourceDecl : SourceDC.get()->decls()) { |
| if (IsKindWeWant(SourceDecl->getKind())) { |
| Decl *ImportedDecl = Forward.Import(const_cast<Decl *>(SourceDecl)); |
| assert(!ImportedDecl || IsSameDC(ImportedDecl->getDeclContext(), DC)); |
| (void)ImportedDecl; |
| } |
| } |
| return false; |
| }); |
| } |
| |
