text: //===- ChainedIncludesSource.cpp - Chained PCHs in Memory -------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  //  This file defines the ChainedIncludesSource class, which converts headers
  //  to chained PCHs in memory, mainly used for testing.
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/Basic/TargetInfo.h"
  #include "clang/Frontend/ASTUnit.h"
  #include "clang/Frontend/CompilerInstance.h"
  #include "clang/Frontend/TextDiagnosticPrinter.h"
  #include "clang/Lex/Preprocessor.h"
  #include "clang/Parse/ParseAST.h"
  #include "clang/Serialization/ASTReader.h"
  #include "clang/Serialization/ASTWriter.h"
  #include "llvm/Support/MemoryBuffer.h"
  
  using namespace clang;
  
  namespace {
  class ChainedIncludesSource : public ExternalSemaSource {
  public:
    ~ChainedIncludesSource() override;
  
    ExternalSemaSource &getFinalReader() const { return *FinalReader; }
  
    std::vector<CompilerInstance *> CIs;
    IntrusiveRefCntPtr<ExternalSemaSource> FinalReader;
  
  protected:
    //===----------------------------------------------------------------------===//
    // ExternalASTSource interface.
    //===----------------------------------------------------------------------===//
  
    Decl *GetExternalDecl(uint32_t ID) override;
    Selector GetExternalSelector(uint32_t ID) override;
    uint32_t GetNumExternalSelectors() override;
    Stmt *GetExternalDeclStmt(uint64_t Offset) override;
    CXXCtorInitializer **GetExternalCXXCtorInitializers(uint64_t Offset) override;
    CXXBaseSpecifier *GetExternalCXXBaseSpecifiers(uint64_t Offset) override;
    bool FindExternalVisibleDeclsByName(const DeclContext *DC,
                                        DeclarationName Name) override;
    ExternalLoadResult
    FindExternalLexicalDecls(const DeclContext *DC,
                             bool (*isKindWeWant)(Decl::Kind),
                             SmallVectorImpl<Decl *> &Result) override;
    void CompleteType(TagDecl *Tag) override;
    void CompleteType(ObjCInterfaceDecl *Class) override;
    void StartedDeserializing() override;
    void FinishedDeserializing() override;
    void StartTranslationUnit(ASTConsumer *Consumer) override;
    void PrintStats() override;
  
    /// Return the amount of memory used by memory buffers, breaking down
    /// by heap-backed versus mmap'ed memory.
    void getMemoryBufferSizes(MemoryBufferSizes &sizes) const override;
  
    //===----------------------------------------------------------------------===//
    // ExternalSemaSource interface.
    //===----------------------------------------------------------------------===//
  
    void InitializeSema(Sema &S) override;
    void ForgetSema() override;
    void ReadMethodPool(Selector Sel) override;
    bool LookupUnqualified(LookupResult &R, Scope *S) override;
  };
  }
  
  static ASTReader *
  createASTReader(CompilerInstance &CI, StringRef pchFile,
                  SmallVectorImpl<std::unique_ptr<llvm::MemoryBuffer>> &MemBufs,
                  SmallVectorImpl<std::string> &bufNames,
                  ASTDeserializationListener *deserialListener = nullptr) {
    Preprocessor &PP = CI.getPreprocessor();
    std::unique_ptr<ASTReader> Reader;
    Reader.reset(new ASTReader(PP, CI.getASTContext(),
                               *CI.getPCHContainerOperations(),
                               /*isysroot=*/"", /*DisableValidation=*/true));
    for (unsigned ti = 0; ti < bufNames.size(); ++ti) {
      StringRef sr(bufNames[ti]);
      Reader->addInMemoryBuffer(sr, std::move(MemBufs[ti]));
    }
    Reader->setDeserializationListener(deserialListener);
    switch (Reader->ReadAST(pchFile, serialization::MK_PCH, SourceLocation(),
                            ASTReader::ARR_None)) {
    case ASTReader::Success:
      // Set the predefines buffer as suggested by the PCH reader.
      PP.setPredefines(Reader->getSuggestedPredefines());
      return Reader.release();
  
    case ASTReader::Failure:
    case ASTReader::Missing:
    case ASTReader::OutOfDate:
    case ASTReader::VersionMismatch:
    case ASTReader::ConfigurationMismatch:
    case ASTReader::HadErrors:
      break;
    }
    return nullptr;
  }
  
  ChainedIncludesSource::~ChainedIncludesSource() {
    for (unsigned i = 0, e = CIs.size(); i != e; ++i)
      delete CIs[i];
  }
  
  IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
      CompilerInstance &CI, IntrusiveRefCntPtr<ExternalSemaSource> &Reader) {
  
    std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
    assert(!includes.empty() && "No '-chain-include' in options!");
  
    IntrusiveRefCntPtr<ChainedIncludesSource> source(new ChainedIncludesSource());
    InputKind IK = CI.getFrontendOpts().Inputs[0].getKind();
  
    SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> SerialBufs;
    SmallVector<std::string, 4> serialBufNames;
  
    for (unsigned i = 0, e = includes.size(); i != e; ++i) {
      bool firstInclude = (i == 0);
      std::unique_ptr<CompilerInvocation> CInvok;
      CInvok.reset(new CompilerInvocation(CI.getInvocation()));
      
      CInvok->getPreprocessorOpts().ChainedIncludes.clear();
      CInvok->getPreprocessorOpts().ImplicitPCHInclude.clear();
      CInvok->getPreprocessorOpts().ImplicitPTHInclude.clear();
      CInvok->getPreprocessorOpts().DisablePCHValidation = true;
      CInvok->getPreprocessorOpts().Includes.clear();
      CInvok->getPreprocessorOpts().MacroIncludes.clear();
      CInvok->getPreprocessorOpts().Macros.clear();
      
      CInvok->getFrontendOpts().Inputs.clear();
      FrontendInputFile InputFile(includes[i], IK);
      CInvok->getFrontendOpts().Inputs.push_back(InputFile);
  
      TextDiagnosticPrinter *DiagClient =
        new TextDiagnosticPrinter(llvm::errs(), new DiagnosticOptions());
      IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
          new DiagnosticsEngine(DiagID, &CI.getDiagnosticOpts(), DiagClient));
  
      std::unique_ptr<CompilerInstance> Clang(
          new CompilerInstance(CI.getPCHContainerOperations()));
      Clang->setInvocation(CInvok.release());
      Clang->setDiagnostics(Diags.get());
      Clang->setTarget(TargetInfo::CreateTargetInfo(
          Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
      Clang->createFileManager();
      Clang->createSourceManager(Clang->getFileManager());
      Clang->createPreprocessor(TU_Prefix);
      Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
                                                   &Clang->getPreprocessor());
      Clang->createASTContext();
  
      auto Buffer = std::make_shared<PCHBuffer>();
      auto consumer = llvm::make_unique<PCHGenerator>(
          Clang->getPreprocessor(), "-", nullptr, /*isysroot=*/"", Buffer);
      Clang->getASTContext().setASTMutationListener(
                                              consumer->GetASTMutationListener());
      Clang->setASTConsumer(std::move(consumer));
      Clang->createSema(TU_Prefix, nullptr);
  
      if (firstInclude) {
        Preprocessor &PP = Clang->getPreprocessor();
        PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
                                               PP.getLangOpts());
      } else {
        assert(!SerialBufs.empty());
        SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> Bufs;
        // TODO: Pass through the existing MemoryBuffer instances instead of
        // allocating new ones.
        for (auto &SB : SerialBufs)
          Bufs.push_back(llvm::MemoryBuffer::getMemBuffer(SB->getBuffer()));
        std::string pchName = includes[i-1];
        llvm::raw_string_ostream os(pchName);
        os << ".pch" << i-1;
        serialBufNames.push_back(os.str());
  
        IntrusiveRefCntPtr<ASTReader> Reader;
        Reader = createASTReader(
            *Clang, pchName, Bufs, serialBufNames,
            Clang->getASTConsumer().GetASTDeserializationListener());
        if (!Reader)
          return nullptr;
        Clang->setModuleManager(Reader);
        Clang->getASTContext().setExternalSource(Reader);
      }
      
      if (!Clang->InitializeSourceManager(InputFile))
        return nullptr;
  
      ParseAST(Clang->getSema());
      Clang->getDiagnosticClient().EndSourceFile();
      assert(Buffer->IsComplete && "serialization did not complete");
      auto &serialAST = Buffer->Data;
      SerialBufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
          StringRef(serialAST.data(), serialAST.size())));
      serialAST.clear();
      source->CIs.push_back(Clang.release());
    }
  
    assert(!SerialBufs.empty());
    std::string pchName = includes.back() + ".pch-final";
    serialBufNames.push_back(pchName);
    Reader = createASTReader(CI, pchName, SerialBufs, serialBufNames);
    if (!Reader)
      return nullptr;
  
    source->FinalReader = Reader;
    return source;
  }
  
  //===----------------------------------------------------------------------===//
  // ExternalASTSource interface.
  //===----------------------------------------------------------------------===//
  
  Decl *ChainedIncludesSource::GetExternalDecl(uint32_t ID) {
    return getFinalReader().GetExternalDecl(ID);
  }
  Selector ChainedIncludesSource::GetExternalSelector(uint32_t ID) {
    return getFinalReader().GetExternalSelector(ID);
  }
  uint32_t ChainedIncludesSource::GetNumExternalSelectors() {
    return getFinalReader().GetNumExternalSelectors();
  }
  Stmt *ChainedIncludesSource::GetExternalDeclStmt(uint64_t Offset) {
    return getFinalReader().GetExternalDeclStmt(Offset);
  }
  CXXBaseSpecifier *
  ChainedIncludesSource::GetExternalCXXBaseSpecifiers(uint64_t Offset) {
    return getFinalReader().GetExternalCXXBaseSpecifiers(Offset);
  }
  CXXCtorInitializer **
  ChainedIncludesSource::GetExternalCXXCtorInitializers(uint64_t Offset) {
    return getFinalReader().GetExternalCXXCtorInitializers(Offset);
  }
  bool
  ChainedIncludesSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
                                                        DeclarationName Name) {
    return getFinalReader().FindExternalVisibleDeclsByName(DC, Name);
  }
  ExternalLoadResult 
  ChainedIncludesSource::FindExternalLexicalDecls(const DeclContext *DC,
                                        bool (*isKindWeWant)(Decl::Kind),
                                        SmallVectorImpl<Decl*> &Result) {
    return getFinalReader().FindExternalLexicalDecls(DC, isKindWeWant, Result);
  }
  void ChainedIncludesSource::CompleteType(TagDecl *Tag) {
    return getFinalReader().CompleteType(Tag);
  }
  void ChainedIncludesSource::CompleteType(ObjCInterfaceDecl *Class) {
    return getFinalReader().CompleteType(Class);
  }
  void ChainedIncludesSource::StartedDeserializing() {
    return getFinalReader().StartedDeserializing();
  }
  void ChainedIncludesSource::FinishedDeserializing() {
    return getFinalReader().FinishedDeserializing();
  }
  void ChainedIncludesSource::StartTranslationUnit(ASTConsumer *Consumer) {
    return getFinalReader().StartTranslationUnit(Consumer);
  }
  void ChainedIncludesSource::PrintStats() {
    return getFinalReader().PrintStats();
  }
  void ChainedIncludesSource::getMemoryBufferSizes(MemoryBufferSizes &sizes)const{
    for (unsigned i = 0, e = CIs.size(); i != e; ++i) {
      if (const ExternalASTSource *eSrc =
          CIs[i]->getASTContext().getExternalSource()) {
        eSrc->getMemoryBufferSizes(sizes);
      }
    }
  
    getFinalReader().getMemoryBufferSizes(sizes);
  }
  
  void ChainedIncludesSource::InitializeSema(Sema &S) {
    return getFinalReader().InitializeSema(S);
  }
  void ChainedIncludesSource::ForgetSema() {
    return getFinalReader().ForgetSema();
  }
  void ChainedIncludesSource::ReadMethodPool(Selector Sel) {
    getFinalReader().ReadMethodPool(Sel);
  }
  bool ChainedIncludesSource::LookupUnqualified(LookupResult &R, Scope *S) {
    return getFinalReader().LookupUnqualified(R, S);
  }
  
  