text: //===--- FrontendAction.cpp -----------------------------------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/Frontend/FrontendAction.h"
  #include "clang/AST/ASTConsumer.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/DeclGroup.h"
  #include "clang/Frontend/ASTUnit.h"
  #include "clang/Frontend/CompilerInstance.h"
  #include "clang/Frontend/FrontendDiagnostic.h"
  #include "clang/Frontend/FrontendPluginRegistry.h"
  #include "clang/Frontend/LayoutOverrideSource.h"
  #include "clang/Frontend/MultiplexConsumer.h"
  #include "clang/Frontend/Utils.h"
  #include "clang/Lex/HeaderSearch.h"
  #include "clang/Lex/Preprocessor.h"
  #include "clang/Lex/PreprocessorOptions.h"
  #include "clang/Parse/ParseAST.h"
  #include "clang/Serialization/ASTDeserializationListener.h"
  #include "clang/Serialization/ASTReader.h"
  #include "clang/Serialization/GlobalModuleIndex.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/FileSystem.h"
  #include "llvm/Support/Path.h"
  #include "llvm/Support/Timer.h"
  #include "llvm/Support/raw_ostream.h"
  #include <system_error>
  using namespace clang;
  
  template class llvm::Registry<clang::PluginASTAction>;
  
  namespace {
  
  class DelegatingDeserializationListener : public ASTDeserializationListener {
    ASTDeserializationListener *Previous;
    bool DeletePrevious;
  
  public:
    explicit DelegatingDeserializationListener(
        ASTDeserializationListener *Previous, bool DeletePrevious)
        : Previous(Previous), DeletePrevious(DeletePrevious) {}
    ~DelegatingDeserializationListener() override {
      if (DeletePrevious)
        delete Previous;
    }
  
    void ReaderInitialized(ASTReader *Reader) override {
      if (Previous)
        Previous->ReaderInitialized(Reader);
    }
    void IdentifierRead(serialization::IdentID ID,
                        IdentifierInfo *II) override {
      if (Previous)
        Previous->IdentifierRead(ID, II);
    }
    void TypeRead(serialization::TypeIdx Idx, QualType T) override {
      if (Previous)
        Previous->TypeRead(Idx, T);
    }
    void DeclRead(serialization::DeclID ID, const Decl *D) override {
      if (Previous)
        Previous->DeclRead(ID, D);
    }
    void SelectorRead(serialization::SelectorID ID, Selector Sel) override {
      if (Previous)
        Previous->SelectorRead(ID, Sel);
    }
    void MacroDefinitionRead(serialization::PreprocessedEntityID PPID,
                             MacroDefinitionRecord *MD) override {
      if (Previous)
        Previous->MacroDefinitionRead(PPID, MD);
    }
  };
  
  /// \brief Dumps deserialized declarations.
  class DeserializedDeclsDumper : public DelegatingDeserializationListener {
  public:
    explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous,
                                     bool DeletePrevious)
        : DelegatingDeserializationListener(Previous, DeletePrevious) {}
  
    void DeclRead(serialization::DeclID ID, const Decl *D) override {
      llvm::outs() << "PCH DECL: " << D->getDeclKindName();
      if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
        llvm::outs() << " - " << *ND;
      llvm::outs() << "\n";
  
      DelegatingDeserializationListener::DeclRead(ID, D);
    }
  };
  
  /// \brief Checks deserialized declarations and emits error if a name
  /// matches one given in command-line using -error-on-deserialized-decl.
  class DeserializedDeclsChecker : public DelegatingDeserializationListener {
    ASTContext &Ctx;
    std::set<std::string> NamesToCheck;
  
  public:
    DeserializedDeclsChecker(ASTContext &Ctx,
                             const std::set<std::string> &NamesToCheck,
                             ASTDeserializationListener *Previous,
                             bool DeletePrevious)
        : DelegatingDeserializationListener(Previous, DeletePrevious), Ctx(Ctx),
          NamesToCheck(NamesToCheck) {}
  
    void DeclRead(serialization::DeclID ID, const Decl *D) override {
      if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
        if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
          unsigned DiagID
            = Ctx.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
                                                   "%0 was deserialized");
          Ctx.getDiagnostics().Report(Ctx.getFullLoc(D->getLocation()), DiagID)
              << ND->getNameAsString();
        }
  
      DelegatingDeserializationListener::DeclRead(ID, D);
    }
  };
  
  } // end anonymous namespace
  
  FrontendAction::FrontendAction() : Instance(nullptr) {}
  
  FrontendAction::~FrontendAction() {}
  
  void FrontendAction::setCurrentInput(const FrontendInputFile &CurrentInput,
                                       std::unique_ptr<ASTUnit> AST) {
    this->CurrentInput = CurrentInput;
    CurrentASTUnit = std::move(AST);
  }
  
  std::unique_ptr<ASTConsumer>
  FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
                                           StringRef InFile) {
    std::unique_ptr<ASTConsumer> Consumer = CreateASTConsumer(CI, InFile);
    if (!Consumer)
      return nullptr;
  
    // If there are no registered plugins we don't need to wrap the consumer
    if (FrontendPluginRegistry::begin() == FrontendPluginRegistry::end())
      return Consumer;
  
    // Collect the list of plugins that go before the main action (in Consumers)
    // or after it (in AfterConsumers)
    std::vector<std::unique_ptr<ASTConsumer>> Consumers;
    std::vector<std::unique_ptr<ASTConsumer>> AfterConsumers;
    for (FrontendPluginRegistry::iterator it = FrontendPluginRegistry::begin(),
                                          ie = FrontendPluginRegistry::end();
         it != ie; ++it) {
      std::unique_ptr<PluginASTAction> P = it->instantiate();
      PluginASTAction::ActionType ActionType = P->getActionType();
      if (ActionType == PluginASTAction::Cmdline) {
        // This is O(|plugins| * |add_plugins|), but since both numbers are
        // way below 50 in practice, that's ok.
        for (size_t i = 0, e = CI.getFrontendOpts().AddPluginActions.size();
             i != e; ++i) {
          if (it->getName() == CI.getFrontendOpts().AddPluginActions[i]) {
            ActionType = PluginASTAction::AddAfterMainAction;
            break;
          }
        }
      }
      if ((ActionType == PluginASTAction::AddBeforeMainAction ||
           ActionType == PluginASTAction::AddAfterMainAction) &&
          P->ParseArgs(CI, CI.getFrontendOpts().PluginArgs[it->getName()])) {
        std::unique_ptr<ASTConsumer> PluginConsumer = P->CreateASTConsumer(CI, InFile);
        if (ActionType == PluginASTAction::AddBeforeMainAction) {
          Consumers.push_back(std::move(PluginConsumer));
        } else {
          AfterConsumers.push_back(std::move(PluginConsumer));
        }
      }
    }
  
    // Add to Consumers the main consumer, then all the plugins that go after it
    Consumers.push_back(std::move(Consumer));
    for (auto &C : AfterConsumers) {
      Consumers.push_back(std::move(C));
    }
  
    return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
  }
  
  bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
                                       const FrontendInputFile &Input) {
    assert(!Instance && "Already processing a source file!");
    assert(!Input.isEmpty() && "Unexpected empty filename!");
    setCurrentInput(Input);
    setCompilerInstance(&CI);
  
    StringRef InputFile = Input.getFile();
    bool HasBegunSourceFile = false;
    if (!BeginInvocation(CI))
      goto failure;
  
    // AST files follow a very different path, since they share objects via the
    // AST unit.
    if (Input.getKind() == IK_AST) {
      assert(!usesPreprocessorOnly() &&
             "Attempt to pass AST file to preprocessor only action!");
      assert(hasASTFileSupport() &&
             "This action does not have AST file support!");
  
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
  
      std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
          InputFile, CI.getPCHContainerReader(), Diags, CI.getFileSystemOpts(),
          CI.getCodeGenOpts().DebugTypeExtRefs);
  
      if (!AST)
        goto failure;
  
      // Inform the diagnostic client we are processing a source file.
      CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
      HasBegunSourceFile = true;
  
      // Set the shared objects, these are reset when we finish processing the
      // file, otherwise the CompilerInstance will happily destroy them.
      CI.setFileManager(&AST->getFileManager());
      CI.setSourceManager(&AST->getSourceManager());
      CI.setPreprocessor(&AST->getPreprocessor());
      CI.setASTContext(&AST->getASTContext());
  
      setCurrentInput(Input, std::move(AST));
  
      // Initialize the action.
      if (!BeginSourceFileAction(CI, InputFile))
        goto failure;
  
      // Create the AST consumer.
      CI.setASTConsumer(CreateWrappedASTConsumer(CI, InputFile));
      if (!CI.hasASTConsumer())
        goto failure;
  
      return true;
    }
  
    if (!CI.hasVirtualFileSystem()) {
      if (IntrusiveRefCntPtr<vfs::FileSystem> VFS =
            createVFSFromCompilerInvocation(CI.getInvocation(),
                                            CI.getDiagnostics()))
        CI.setVirtualFileSystem(VFS);
      else
        goto failure;
    }
  
    // Set up the file and source managers, if needed.
    if (!CI.hasFileManager())
      CI.createFileManager();
    if (!CI.hasSourceManager())
      CI.createSourceManager(CI.getFileManager());
  
    // IR files bypass the rest of initialization.
    if (Input.getKind() == IK_LLVM_IR) {
      assert(hasIRSupport() &&
             "This action does not have IR file support!");
  
      // Inform the diagnostic client we are processing a source file.
      CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
      HasBegunSourceFile = true;
  
      // Initialize the action.
      if (!BeginSourceFileAction(CI, InputFile))
        goto failure;
  
      // Initialize the main file entry.
      if (!CI.InitializeSourceManager(CurrentInput))
        goto failure;
  
      return true;
    }
  
    // If the implicit PCH include is actually a directory, rather than
    // a single file, search for a suitable PCH file in that directory.
    if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
      FileManager &FileMgr = CI.getFileManager();
      PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
      StringRef PCHInclude = PPOpts.ImplicitPCHInclude;
      std::string SpecificModuleCachePath = CI.getSpecificModuleCachePath();
      if (const DirectoryEntry *PCHDir = FileMgr.getDirectory(PCHInclude)) {
        std::error_code EC;
        SmallString<128> DirNative;
        llvm::sys::path::native(PCHDir->getName(), DirNative);
        bool Found = false;
        for (llvm::sys::fs::directory_iterator Dir(DirNative, EC), DirEnd;
             Dir != DirEnd && !EC; Dir.increment(EC)) {
          // Check whether this is an acceptable AST file.
          if (ASTReader::isAcceptableASTFile(
                  Dir->path(), FileMgr, CI.getPCHContainerReader(),
                  CI.getLangOpts(), CI.getTargetOpts(), CI.getPreprocessorOpts(),
                  SpecificModuleCachePath)) {
            PPOpts.ImplicitPCHInclude = Dir->path();
            Found = true;
            break;
          }
        }
  
        if (!Found) {
          CI.getDiagnostics().Report(diag::err_fe_no_pch_in_dir) << PCHInclude;
          goto failure;
        }
      }
    }
  
    // Set up the preprocessor if needed. When parsing model files the
    // preprocessor of the original source is reused.
    if (!isModelParsingAction())
      CI.createPreprocessor(getTranslationUnitKind());
  
    // Inform the diagnostic client we are processing a source file.
    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(),
                                             &CI.getPreprocessor());
    HasBegunSourceFile = true;
  
    // Initialize the action.
    if (!BeginSourceFileAction(CI, InputFile))
      goto failure;
  
    // Initialize the main file entry. It is important that this occurs after
    // BeginSourceFileAction, which may change CurrentInput during module builds.
    if (!CI.InitializeSourceManager(CurrentInput))
      goto failure;
  
    // Create the AST context and consumer unless this is a preprocessor only
    // action.
    if (!usesPreprocessorOnly()) {
      // Parsing a model file should reuse the existing ASTContext.
      if (!isModelParsingAction())
        CI.createASTContext();
  
      std::unique_ptr<ASTConsumer> Consumer =
          CreateWrappedASTConsumer(CI, InputFile);
      if (!Consumer)
        goto failure;
  
      // FIXME: should not overwrite ASTMutationListener when parsing model files?
      if (!isModelParsingAction())
        CI.getASTContext().setASTMutationListener(Consumer->GetASTMutationListener());
  
      if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
        // Convert headers to PCH and chain them.
        IntrusiveRefCntPtr<ExternalSemaSource> source, FinalReader;
        source = createChainedIncludesSource(CI, FinalReader);
        if (!source)
          goto failure;
        CI.setModuleManager(static_cast<ASTReader *>(FinalReader.get()));
        CI.getASTContext().setExternalSource(source);
      } else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
        // Use PCH.
        assert(hasPCHSupport() && "This action does not have PCH support!");
        ASTDeserializationListener *DeserialListener =
            Consumer->GetASTDeserializationListener();
        bool DeleteDeserialListener = false;
        if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls) {
          DeserialListener = new DeserializedDeclsDumper(DeserialListener,
                                                         DeleteDeserialListener);
          DeleteDeserialListener = true;
        }
        if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty()) {
          DeserialListener = new DeserializedDeclsChecker(
              CI.getASTContext(),
              CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
              DeserialListener, DeleteDeserialListener);
          DeleteDeserialListener = true;
        }
        CI.createPCHExternalASTSource(
            CI.getPreprocessorOpts().ImplicitPCHInclude,
            CI.getPreprocessorOpts().DisablePCHValidation,
            CI.getPreprocessorOpts().AllowPCHWithCompilerErrors, DeserialListener,
            DeleteDeserialListener);
        if (!CI.getASTContext().getExternalSource())
          goto failure;
      }
  
      CI.setASTConsumer(std::move(Consumer));
      if (!CI.hasASTConsumer())
        goto failure;
    }
  
    // Initialize built-in info as long as we aren't using an external AST
    // source.
    if (!CI.hasASTContext() || !CI.getASTContext().getExternalSource()) {
      Preprocessor &PP = CI.getPreprocessor();
  
      // If modules are enabled, create the module manager before creating
      // any builtins, so that all declarations know that they might be
      // extended by an external source.
      if (CI.getLangOpts().Modules)
        CI.createModuleManager();
  
      PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
                                             PP.getLangOpts());
    } else {
      // FIXME: If this is a problem, recover from it by creating a multiplex
      // source.
      assert((!CI.getLangOpts().Modules || CI.getModuleManager()) &&
             "modules enabled but created an external source that "
             "doesn't support modules");
    }
  
    // If we were asked to load any module map files, do so now.
    for (const auto &Filename : CI.getFrontendOpts().ModuleMapFiles) {
      if (auto *File = CI.getFileManager().getFile(Filename))
        CI.getPreprocessor().getHeaderSearchInfo().loadModuleMapFile(
            File, /*IsSystem*/false);
      else
        CI.getDiagnostics().Report(diag::err_module_map_not_found) << Filename;
    }
  
    // If we were asked to load any module files, do so now.
    for (const auto &ModuleFile : CI.getFrontendOpts().ModuleFiles)
      if (!CI.loadModuleFile(ModuleFile))
        goto failure;
  
    // If there is a layout overrides file, attach an external AST source that
    // provides the layouts from that file.
    if (!CI.getFrontendOpts().OverrideRecordLayoutsFile.empty() && 
        CI.hasASTContext() && !CI.getASTContext().getExternalSource()) {
      IntrusiveRefCntPtr<ExternalASTSource> 
        Override(new LayoutOverrideSource(
                       CI.getFrontendOpts().OverrideRecordLayoutsFile));
      CI.getASTContext().setExternalSource(Override);
    }
  
    return true;
  
    // If we failed, reset state since the client will not end up calling the
    // matching EndSourceFile().
    failure:
    if (isCurrentFileAST()) {
      CI.setASTContext(nullptr);
      CI.setPreprocessor(nullptr);
      CI.setSourceManager(nullptr);
      CI.setFileManager(nullptr);
    }
  
    if (HasBegunSourceFile)
      CI.getDiagnosticClient().EndSourceFile();
    CI.clearOutputFiles(/*EraseFiles=*/true);
    setCurrentInput(FrontendInputFile());
    setCompilerInstance(nullptr);
    return false;
  }
  
  bool FrontendAction::Execute() {
    CompilerInstance &CI = getCompilerInstance();
  
    if (CI.hasFrontendTimer()) {
      llvm::TimeRegion Timer(CI.getFrontendTimer());
      ExecuteAction();
    }
    else ExecuteAction();
  
    // If we are supposed to rebuild the global module index, do so now unless
    // there were any module-build failures.
    if (CI.shouldBuildGlobalModuleIndex() && CI.hasFileManager() &&
        CI.hasPreprocessor()) {
      StringRef Cache =
          CI.getPreprocessor().getHeaderSearchInfo().getModuleCachePath();
      if (!Cache.empty())
        GlobalModuleIndex::writeIndex(CI.getFileManager(),
                                      CI.getPCHContainerReader(), Cache);
    }
  
    return true;
  }
  
  void FrontendAction::EndSourceFile() {
    CompilerInstance &CI = getCompilerInstance();
  
    // Inform the diagnostic client we are done with this source file.
    CI.getDiagnosticClient().EndSourceFile();
  
    // Inform the preprocessor we are done.
    if (CI.hasPreprocessor())
      CI.getPreprocessor().EndSourceFile();
  
    // Finalize the action.
    EndSourceFileAction();
  
    // Sema references the ast consumer, so reset sema first.
    //
    // FIXME: There is more per-file stuff we could just drop here?
    bool DisableFree = CI.getFrontendOpts().DisableFree;
    if (DisableFree) {
      CI.resetAndLeakSema();
      CI.resetAndLeakASTContext();
      BuryPointer(CI.takeASTConsumer().get());
    } else {
      CI.setSema(nullptr);
      CI.setASTContext(nullptr);
      CI.setASTConsumer(nullptr);
    }
  
    if (CI.getFrontendOpts().ShowStats) {
      llvm::errs() << "\nSTATISTICS FOR '" << getCurrentFile() << "':\n";
      CI.getPreprocessor().PrintStats();
      CI.getPreprocessor().getIdentifierTable().PrintStats();
      CI.getPreprocessor().getHeaderSearchInfo().PrintStats();
      CI.getSourceManager().PrintStats();
      llvm::errs() << "\n";
    }
  
    // Cleanup the output streams, and erase the output files if instructed by the
    // FrontendAction.
    CI.clearOutputFiles(/*EraseFiles=*/shouldEraseOutputFiles());
  
    if (isCurrentFileAST()) {
      if (DisableFree) {
        CI.resetAndLeakPreprocessor();
        CI.resetAndLeakSourceManager();
        CI.resetAndLeakFileManager();
      } else {
        CI.setPreprocessor(nullptr);
        CI.setSourceManager(nullptr);
        CI.setFileManager(nullptr);
      }
    }
  
    setCompilerInstance(nullptr);
    setCurrentInput(FrontendInputFile());
  }
  
  bool FrontendAction::shouldEraseOutputFiles() {
    return getCompilerInstance().getDiagnostics().hasErrorOccurred();
  }
  
  //===----------------------------------------------------------------------===//
  // Utility Actions
  //===----------------------------------------------------------------------===//
  
  void ASTFrontendAction::ExecuteAction() {
    CompilerInstance &CI = getCompilerInstance();
    if (!CI.hasPreprocessor())
      return;
  
    // FIXME: Move the truncation aspect of this into Sema, we delayed this till
    // here so the source manager would be initialized.
    if (hasCodeCompletionSupport() &&
        !CI.getFrontendOpts().CodeCompletionAt.FileName.empty())
      CI.createCodeCompletionConsumer();
  
    // Use a code completion consumer?
    CodeCompleteConsumer *CompletionConsumer = nullptr;
    if (CI.hasCodeCompletionConsumer())
      CompletionConsumer = &CI.getCodeCompletionConsumer();
  
    if (!CI.hasSema())
      CI.createSema(getTranslationUnitKind(), CompletionConsumer);
  
    ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats,
             CI.getFrontendOpts().SkipFunctionBodies);
  }
  
  void PluginASTAction::anchor() { }
  
  std::unique_ptr<ASTConsumer>
  PreprocessorFrontendAction::CreateASTConsumer(CompilerInstance &CI,
                                                StringRef InFile) {
    llvm_unreachable("Invalid CreateASTConsumer on preprocessor action!");
  }
  
  std::unique_ptr<ASTConsumer>
  WrapperFrontendAction::CreateASTConsumer(CompilerInstance &CI,
                                           StringRef InFile) {
    return WrappedAction->CreateASTConsumer(CI, InFile);
  }
  bool WrapperFrontendAction::BeginInvocation(CompilerInstance &CI) {
    return WrappedAction->BeginInvocation(CI);
  }
  bool WrapperFrontendAction::BeginSourceFileAction(CompilerInstance &CI,
                                                    StringRef Filename) {
    WrappedAction->setCurrentInput(getCurrentInput());
    WrappedAction->setCompilerInstance(&CI);
    auto Ret = WrappedAction->BeginSourceFileAction(CI, Filename);
    // BeginSourceFileAction may change CurrentInput, e.g. during module builds.
    setCurrentInput(WrappedAction->getCurrentInput());
    return Ret;
  }
  void WrapperFrontendAction::ExecuteAction() {
    WrappedAction->ExecuteAction();
  }
  void WrapperFrontendAction::EndSourceFileAction() {
    WrappedAction->EndSourceFileAction();
  }
  
  bool WrapperFrontendAction::usesPreprocessorOnly() const {
    return WrappedAction->usesPreprocessorOnly();
  }
  TranslationUnitKind WrapperFrontendAction::getTranslationUnitKind() {
    return WrappedAction->getTranslationUnitKind();
  }
  bool WrapperFrontendAction::hasPCHSupport() const {
    return WrappedAction->hasPCHSupport();
  }
  bool WrapperFrontendAction::hasASTFileSupport() const {
    return WrappedAction->hasASTFileSupport();
  }
  bool WrapperFrontendAction::hasIRSupport() const {
    return WrappedAction->hasIRSupport();
  }
  bool WrapperFrontendAction::hasCodeCompletionSupport() const {
    return WrappedAction->hasCodeCompletionSupport();
  }
  
  WrapperFrontendAction::WrapperFrontendAction(
      std::unique_ptr<FrontendAction> WrappedAction)
    : WrappedAction(std::move(WrappedAction)) {}
  
  