C++ MemoryBufferRef::getBufferSize方法代码示例

Error PDBFile::parseFileHeaders() {
  std::error_code EC;
  MemoryBufferRef BufferRef = *Context->Buffer;

  // Make sure the file is sufficiently large to hold a super block.
  // Do this before attempting to read the super block.
  if (BufferRef.getBufferSize() < sizeof(SuperBlock))
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "Does not contain superblock");

  Context->SB =
      reinterpret_cast<const SuperBlock *>(BufferRef.getBufferStart());
  const SuperBlock *SB = Context->SB;
  // Check the magic bytes.
  if (memcmp(SB->MagicBytes, Magic, sizeof(Magic)) != 0)
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "MSF magic header doesn't match");

  // We don't support blocksizes which aren't a multiple of four bytes.
  if (SB->BlockSize % sizeof(support::ulittle32_t) != 0)
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "Block size is not multiple of 4.");

  switch (SB->BlockSize) {
  case 512: case 1024: case 2048: case 4096:
    break;
  default:
    // An invalid block size suggests a corrupt PDB file.
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "Unsupported block size.");
  }

  if (BufferRef.getBufferSize() % SB->BlockSize != 0)
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "File size is not a multiple of block size");

  // We don't support directories whose sizes aren't a multiple of four bytes.
  if (SB->NumDirectoryBytes % sizeof(support::ulittle32_t) != 0)
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "Directory size is not multiple of 4.");

  // The number of blocks which comprise the directory is a simple function of
  // the number of bytes it contains.
  uint64_t NumDirectoryBlocks = getNumDirectoryBlocks();

  // The block map, as we understand it, is a block which consists of a list of
  // block numbers.
  // It is unclear what would happen if the number of blocks couldn't fit on a
  // single block.
  if (NumDirectoryBlocks > SB->BlockSize / sizeof(support::ulittle32_t))
    return make_error<RawError>(raw_error_code::corrupt_file,
                                "Too many directory blocks.");

  // Make sure the directory block array fits within the file.
  if (auto EC = checkOffset(BufferRef, getDirectoryBlockArray()))
    return EC;

  return Error::success();
}

// Returns false if size is greater than the buffer size. And sets ec.
static bool checkSize(MemoryBufferRef M, std::error_code &EC, uint64_t Size) {
  if (M.getBufferSize() < Size) {
    EC = object_error::unexpected_eof;
    return false;
  }
  return true;
}

 void notifyObjectCompiled(const Module *M, MemoryBufferRef Obj) override {
   const std::string &ModuleID = M->getModuleIdentifier();
   std::string CacheName;
   if (!getCacheFilename(ModuleID, CacheName))
     return;
   if (!CacheDir.empty()) { // Create user-defined cache dir.
     SmallString<128> dir(sys::path::parent_path(CacheName));
     sys::fs::create_directories(Twine(dir));
   }
   std::error_code EC;
   raw_fd_ostream outfile(CacheName, EC, sys::fs::F_None);
   outfile.write(Obj.getBufferStart(), Obj.getBufferSize());
   outfile.close();
 }

// Parse the module summary index out of an IR file and return the summary
// index object if found, or nullptr if not.
Expected<std::unique_ptr<ModuleSummaryIndex>>
llvm::getModuleSummaryIndexForFile(StringRef Path) {
  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
      MemoryBuffer::getFileOrSTDIN(Path);
  std::error_code EC = FileOrErr.getError();
  if (EC)
    return errorCodeToError(EC);
  MemoryBufferRef BufferRef = (FileOrErr.get())->getMemBufferRef();
  if (IgnoreEmptyThinLTOIndexFile && !BufferRef.getBufferSize())
    return nullptr;
  Expected<std::unique_ptr<object::ModuleSummaryIndexObjectFile>> ObjOrErr =
      object::ModuleSummaryIndexObjectFile::create(BufferRef);
  if (!ObjOrErr)
    return ObjOrErr.takeError();

  object::ModuleSummaryIndexObjectFile &Obj = **ObjOrErr;
  return Obj.takeIndex();
}

std::error_code PDBFile::parseFileHeaders() {
  std::error_code EC;
  MemoryBufferRef BufferRef = *Context->Buffer;

  Context->SB =
      reinterpret_cast<const SuperBlock *>(BufferRef.getBufferStart());
  const SuperBlock *SB = Context->SB;

  // Make sure the file is sufficiently large to hold a super block.
  if (BufferRef.getBufferSize() < sizeof(SuperBlock))
    return std::make_error_code(std::errc::illegal_byte_sequence);

  // Check the magic bytes.
  if (memcmp(SB->MagicBytes, Magic, sizeof(Magic)) != 0)
    return std::make_error_code(std::errc::illegal_byte_sequence);

  // We don't support blocksizes which aren't a multiple of four bytes.
  if (SB->BlockSize == 0 || SB->BlockSize % sizeof(support::ulittle32_t) != 0)
    return std::make_error_code(std::errc::not_supported);

  // We don't support directories whose sizes aren't a multiple of four bytes.
  if (SB->NumDirectoryBytes % sizeof(support::ulittle32_t) != 0)
    return std::make_error_code(std::errc::not_supported);

  // The number of blocks which comprise the directory is a simple function of
  // the number of bytes it contains.
  uint64_t NumDirectoryBlocks = getNumDirectoryBlocks();

  // The block map, as we understand it, is a block which consists of a list of
  // block numbers.
  // It is unclear what would happen if the number of blocks couldn't fit on a
  // single block.
  if (NumDirectoryBlocks > SB->BlockSize / sizeof(support::ulittle32_t))
    return std::make_error_code(std::errc::illegal_byte_sequence);

  return std::error_code();
}

static Expected<std::vector<MemberData>>
computeMemberData(raw_ostream &StringTable, raw_ostream &SymNames,
                  object::Archive::Kind Kind, bool Thin, bool Deterministic,
                  ArrayRef<NewArchiveMember> NewMembers) {
  static char PaddingData[8] = {'\n', '\n', '\n', '\n', '\n', '\n', '\n', '\n'};

  // This ignores the symbol table, but we only need the value mod 8 and the
  // symbol table is aligned to be a multiple of 8 bytes
  uint64_t Pos = 0;

  std::vector<MemberData> Ret;
  bool HasObject = false;

  // Deduplicate long member names in the string table and reuse earlier name
  // offsets. This especially saves space for COFF Import libraries where all
  // members have the same name.
  StringMap<uint64_t> MemberNames;

  // UniqueTimestamps is a special case to improve debugging on Darwin:
  //
  // The Darwin linker does not link debug info into the final
  // binary. Instead, it emits entries of type N_OSO in in the output
  // binary's symbol table, containing references to the linked-in
  // object files. Using that reference, the debugger can read the
  // debug data directly from the object files. Alternatively, an
  // invocation of 'dsymutil' will link the debug data from the object
  // files into a dSYM bundle, which can be loaded by the debugger,
  // instead of the object files.
  //
  // For an object file, the N_OSO entries contain the absolute path
  // path to the file, and the file's timestamp. For an object
  // included in an archive, the path is formatted like
  // "/absolute/path/to/archive.a(member.o)", and the timestamp is the
  // archive member's timestamp, rather than the archive's timestamp.
  //
  // However, this doesn't always uniquely identify an object within
  // an archive -- an archive file can have multiple entries with the
  // same filename. (This will happen commonly if the original object
  // files started in different directories.) The only way they get
  // distinguished, then, is via the timestamp. But this process is
  // unable to find the correct object file in the archive when there
  // are two files of the same name and timestamp.
  //
  // Additionally, timestamp==0 is treated specially, and causes the
  // timestamp to be ignored as a match criteria.
  //
  // That will "usually" work out okay when creating an archive not in
  // deterministic timestamp mode, because the objects will probably
  // have been created at different timestamps.
  //
  // To ameliorate this problem, in deterministic archive mode (which
  // is the default), on Darwin we will emit a unique non-zero
  // timestamp for each entry with a duplicated name. This is still
  // deterministic: the only thing affecting that timestamp is the
  // order of the files in the resultant archive.
  //
  // See also the functions that handle the lookup:
  // in lldb: ObjectContainerBSDArchive::Archive::FindObject()
  // in llvm/tools/dsymutil: BinaryHolder::GetArchiveMemberBuffers().
  bool UniqueTimestamps = Deterministic && isDarwin(Kind);
  std::map<StringRef, unsigned> FilenameCount;
  if (UniqueTimestamps) {
    for (const NewArchiveMember &M : NewMembers)
      FilenameCount[M.MemberName]++;
    for (auto &Entry : FilenameCount)
      Entry.second = Entry.second > 1 ? 1 : 0;
  }

  for (const NewArchiveMember &M : NewMembers) {
    std::string Header;
    raw_string_ostream Out(Header);

    MemoryBufferRef Buf = M.Buf->getMemBufferRef();
    StringRef Data = Thin ? "" : Buf.getBuffer();

    // ld64 expects the members to be 8-byte aligned for 64-bit content and at
    // least 4-byte aligned for 32-bit content.  Opt for the larger encoding
    // uniformly.  This matches the behaviour with cctools and ensures that ld64
    // is happy with archives that we generate.
    unsigned MemberPadding =
        isDarwin(Kind) ? OffsetToAlignment(Data.size(), 8) : 0;
    unsigned TailPadding = OffsetToAlignment(Data.size() + MemberPadding, 2);
    StringRef Padding = StringRef(PaddingData, MemberPadding + TailPadding);

    sys::TimePoint<std::chrono::seconds> ModTime;
    if (UniqueTimestamps)
      // Increment timestamp for each file of a given name.
      ModTime = sys::toTimePoint(FilenameCount[M.MemberName]++);
    else
      ModTime = M.ModTime;
    printMemberHeader(Out, Pos, StringTable, MemberNames, Kind, Thin, M,
                      ModTime, Buf.getBufferSize() + MemberPadding);
    Out.flush();

    Expected<std::vector<unsigned>> Symbols =
        getSymbols(Buf, SymNames, HasObject);
    if (auto E = Symbols.takeError())
      return std::move(E);

    Pos += Header.size() + Data.size() + Padding.size();
//.........这里部分代码省略.........

Error PDBFile::parseStreamData() {
  assert(Context && Context->SB);

  bool SeenNumStreams = false;
  uint32_t NumStreams = 0;
  uint32_t StreamIdx = 0;
  uint64_t DirectoryBytesRead = 0;

  MemoryBufferRef M = *Context->Buffer;
  const SuperBlock *SB = Context->SB;

  auto DirectoryBlocks = getDirectoryBlockArray();

  // The structure of the directory is as follows:
  //    struct PDBDirectory {
  //      uint32_t NumStreams;
  //      uint32_t StreamSizes[NumStreams];
  //      uint32_t StreamMap[NumStreams][];
  //    };
  //
  //  Empty streams don't consume entries in the StreamMap.
  for (uint32_t DirectoryBlockAddr : DirectoryBlocks) {
    uint64_t DirectoryBlockOffset =
        blockToOffset(DirectoryBlockAddr, SB->BlockSize);
    auto DirectoryBlock =
        makeArrayRef(reinterpret_cast<const support::ulittle32_t *>(
                         M.getBufferStart() + DirectoryBlockOffset),
                     SB->BlockSize / sizeof(support::ulittle32_t));
    if (auto EC = checkOffset(M, DirectoryBlock))
      return EC;

    // We read data out of the directory four bytes at a time.  Depending on
    // where we are in the directory, the contents may be: the number of streams
    // in the directory, a stream's size, or a block in the stream map.
    for (uint32_t Data : DirectoryBlock) {
      // Don't read beyond the end of the directory.
      if (DirectoryBytesRead == SB->NumDirectoryBytes)
        break;

      DirectoryBytesRead += sizeof(Data);

      // This data must be the number of streams if we haven't seen it yet.
      if (!SeenNumStreams) {
        NumStreams = Data;
        SeenNumStreams = true;
        continue;
      }
      // This data must be a stream size if we have not seen them all yet.
      if (Context->StreamSizes.size() < NumStreams) {
        // It seems like some streams have their set to -1 when their contents
        // are not present.  Treat them like empty streams for now.
        if (Data == UINT32_MAX)
          Context->StreamSizes.push_back(0);
        else
          Context->StreamSizes.push_back(Data);
        continue;
      }

      // This data must be a stream block number if we have seen all of the
      // stream sizes.
      std::vector<uint32_t> *StreamBlocks = nullptr;
      // Figure out which stream this block number belongs to.
      while (StreamIdx < NumStreams) {
        uint64_t NumExpectedStreamBlocks =
            bytesToBlocks(Context->StreamSizes[StreamIdx], SB->BlockSize);
        StreamBlocks = &Context->StreamMap[StreamIdx];
        if (NumExpectedStreamBlocks > StreamBlocks->size())
          break;
        ++StreamIdx;
      }
      // It seems this block doesn't belong to any stream?  The stream is either
      // corrupt or something more mysterious is going on.
      if (StreamIdx == NumStreams)
        return make_error<RawError>(raw_error_code::corrupt_file,
                                    "Orphaned block found?");

      uint64_t BlockOffset = blockToOffset(Data, getBlockSize());
      if (BlockOffset + getBlockSize() < BlockOffset)
        return make_error<RawError>(raw_error_code::corrupt_file,
                                    "Bogus stream block number");
      if (BlockOffset + getBlockSize() > M.getBufferSize())
        return make_error<RawError>(raw_error_code::corrupt_file,
                                    "Stream block number is out of bounds");

      StreamBlocks->push_back(Data);
    }
  }

  if (Context->StreamSizes.size() != NumStreams)
    return make_error<RawError>(
        raw_error_code::corrupt_file,
        "The directory has fewer streams then expected");

  for (uint32_t I = 0; I != NumStreams; ++I) {
    uint64_t NumExpectedStreamBlocks =
        bytesToBlocks(getStreamByteSize(I), getBlockSize());
    size_t NumStreamBlocks = getStreamBlockList(I).size();
    if (NumExpectedStreamBlocks != NumStreamBlocks)
      return make_error<RawError>(raw_error_code::corrupt_file,
                                  "The number of stream blocks is not "
//.........这里部分代码省略.........