C++ BitstreamWriter::EnterSubblock方法代码示例

void
GlobalModuleIndexBuilder::emitBlockInfoBlock(llvm::BitstreamWriter &Stream) {
  SmallVector<uint64_t, 64> Record;
  Stream.EnterSubblock(llvm::bitc::BLOCKINFO_BLOCK_ID, 3);

#define BLOCK(X) emitBlockID(X ## _ID, #X, Stream, Record)
#define RECORD(X) emitRecordID(X, #X, Stream, Record)
  BLOCK(GLOBAL_INDEX_BLOCK);
  RECORD(INDEX_METADATA);
  RECORD(MODULE);
  RECORD(IDENTIFIER_INDEX);
#undef RECORD
#undef BLOCK

  Stream.ExitBlock();
}

void GlobalModuleIndexBuilder::writeIndex(llvm::BitstreamWriter &Stream) {
  using namespace llvm;

  // Emit the file header.
  Stream.Emit((unsigned)'B', 8);
  Stream.Emit((unsigned)'C', 8);
  Stream.Emit((unsigned)'G', 8);
  Stream.Emit((unsigned)'I', 8);

  // Write the block-info block, which describes the records in this bitcode
  // file.
  emitBlockInfoBlock(Stream);

  Stream.EnterSubblock(GLOBAL_INDEX_BLOCK_ID, 3);

  // Write the metadata.
  SmallVector<uint64_t, 2> Record;
  Record.push_back(CurrentVersion);
  Stream.EmitRecord(INDEX_METADATA, Record);

  // Write the set of known module files.
  for (ModuleFilesMap::iterator M = ModuleFiles.begin(),
                                MEnd = ModuleFiles.end();
       M != MEnd; ++M) {
    Record.clear();
    Record.push_back(M->second.ID);
    Record.push_back(M->first->getSize());
    Record.push_back(M->first->getModificationTime());

    // File name
    StringRef Name(M->first->getName());
    Record.push_back(Name.size());
    Record.append(Name.begin(), Name.end());

    // Dependencies
    Record.push_back(M->second.Dependencies.size());
    Record.append(M->second.Dependencies.begin(), M->second.Dependencies.end());
    Stream.EmitRecord(MODULE, Record);
  }

  // Write the identifier -> module file mapping.
  {
    llvm::OnDiskChainedHashTableGenerator<IdentifierIndexWriterTrait> Generator;
    IdentifierIndexWriterTrait Trait;

    // Populate the hash table.
    for (InterestingIdentifierMap::iterator I = InterestingIdentifiers.begin(),
                                            IEnd = InterestingIdentifiers.end();
         I != IEnd; ++I) {
      Generator.insert(I->first(), I->second, Trait);
    }

    // Create the on-disk hash table in a buffer.
    SmallString<4096> IdentifierTable;
    uint32_t BucketOffset;
    {
      using namespace llvm::support;
      llvm::raw_svector_ostream Out(IdentifierTable);
      // Make sure that no bucket is at offset 0
      endian::Writer<little>(Out).write<uint32_t>(0);
      BucketOffset = Generator.Emit(Out, Trait);
    }

    // Create a blob abbreviation
    BitCodeAbbrev *Abbrev = new BitCodeAbbrev();
    Abbrev->Add(BitCodeAbbrevOp(IDENTIFIER_INDEX));
    Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
    Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
    unsigned IDTableAbbrev = Stream.EmitAbbrev(Abbrev);

    // Write the identifier table
    Record.clear();
    Record.push_back(IDENTIFIER_INDEX);
    Record.push_back(BucketOffset);
    Stream.EmitRecordWithBlob(IDTableAbbrev, Record, IdentifierTable.str());
  }

  Stream.ExitBlock();
}

bool GlobalModuleIndexBuilder::writeIndex(llvm::BitstreamWriter &Stream) {
  for (auto MapEntry : ImportedModuleFiles) {
    auto *File = MapEntry.first;
    ImportedModuleFileInfo &Info = MapEntry.second;
    if (getModuleFileInfo(File).Signature) {
      if (getModuleFileInfo(File).Signature != Info.StoredSignature)
        // Verify Signature.
        return true;
    } else if (Info.StoredSize != File->getSize() ||
               Info.StoredModTime != File->getModificationTime())
      // Verify Size and ModTime.
      return true;
  }

  using namespace llvm;
  llvm::TimeTraceScope TimeScope("Module WriteIndex", StringRef(""));

  // Emit the file header.
  Stream.Emit((unsigned)'B', 8);
  Stream.Emit((unsigned)'C', 8);
  Stream.Emit((unsigned)'G', 8);
  Stream.Emit((unsigned)'I', 8);

  // Write the block-info block, which describes the records in this bitcode
  // file.
  emitBlockInfoBlock(Stream);

  Stream.EnterSubblock(GLOBAL_INDEX_BLOCK_ID, 3);

  // Write the metadata.
  SmallVector<uint64_t, 2> Record;
  Record.push_back(CurrentVersion);
  Stream.EmitRecord(INDEX_METADATA, Record);

  // Write the set of known module files.
  for (ModuleFilesMap::iterator M = ModuleFiles.begin(),
                                MEnd = ModuleFiles.end();
       M != MEnd; ++M) {
    Record.clear();
    Record.push_back(M->second.ID);
    Record.push_back(M->first->getSize());
    Record.push_back(M->first->getModificationTime());

    // File name
    StringRef Name(M->first->getName());
    Record.push_back(Name.size());
    Record.append(Name.begin(), Name.end());

    // Dependencies
    Record.push_back(M->second.Dependencies.size());
    Record.append(M->second.Dependencies.begin(), M->second.Dependencies.end());
    Stream.EmitRecord(MODULE, Record);
  }

  // Write the identifier -> module file mapping.
  {
    llvm::OnDiskChainedHashTableGenerator<IdentifierIndexWriterTrait> Generator;
    IdentifierIndexWriterTrait Trait;

    // Populate the hash table.
    for (InterestingIdentifierMap::iterator I = InterestingIdentifiers.begin(),
                                            IEnd = InterestingIdentifiers.end();
         I != IEnd; ++I) {
      Generator.insert(I->first(), I->second, Trait);
    }

    // Create the on-disk hash table in a buffer.
    SmallString<4096> IdentifierTable;
    uint32_t BucketOffset;
    {
      using namespace llvm::support;
      llvm::raw_svector_ostream Out(IdentifierTable);
      // Make sure that no bucket is at offset 0
      endian::write<uint32_t>(Out, 0, little);
      BucketOffset = Generator.Emit(Out, Trait);
    }

    // Create a blob abbreviation
    auto Abbrev = std::make_shared<BitCodeAbbrev>();
    Abbrev->Add(BitCodeAbbrevOp(IDENTIFIER_INDEX));
    Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
    Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
    unsigned IDTableAbbrev = Stream.EmitAbbrev(std::move(Abbrev));

    // Write the identifier table
    uint64_t Record[] = {IDENTIFIER_INDEX, BucketOffset};
    Stream.EmitRecordWithBlob(IDTableAbbrev, Record, IdentifierTable);
  }

  Stream.ExitBlock();
  return false;
}