C++ MemoryBuffer::getBufferStart方法代码示例

/// Detect the likely line ending style of \p FromFile by examining the first
/// newline found within it.
static StringRef DetectEOL(const MemoryBuffer &FromFile) {
  // detect what line endings the file uses, so that added content does not mix
  // the style
  const char *Pos = strchr(FromFile.getBufferStart(), '\n');
  if (Pos == NULL)
    return "\n";
  if (Pos + 1 < FromFile.getBufferEnd() && Pos[1] == '\r')
    return "\n\r";
  if (Pos - 1 >= FromFile.getBufferStart() && Pos[-1] == '\r')
    return "\r\n";
  return "\n";
}

/// Detect the likely line ending style of \p FromFile by examining the first
/// newline found within it.
static StringRef DetectEOL(const MemoryBuffer &FromFile) {
  // Detect what line endings the file uses, so that added content does not mix
  // the style. We need to check for "\r\n" first because "\n\r" will match
  // "\r\n\r\n".
  const char *Pos = strchr(FromFile.getBufferStart(), '\n');
  if (!Pos)
    return "\n";
  if (Pos - 1 >= FromFile.getBufferStart() && Pos[-1] == '\r')
    return "\r\n";
  if (Pos + 1 < FromFile.getBufferEnd() && Pos[1] == '\r')
    return "\n\r";
  return "\n";
}

line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
                             char CommentMarker)
    : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
      CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
      CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
                  0) {
  // Ensure that if we are constructed on a non-empty memory buffer that it is
  // a null terminated buffer.
  if (Buffer.getBufferSize()) {
    assert(Buffer.getBufferEnd()[0] == '\0');
    // Make sure we don't skip a leading newline if we're keeping blanks
    if (SkipBlanks || !isAtLineEnd(Buffer.getBufferStart()))
      advance();
  }
}

  void WriteBundle(raw_fd_ostream &OS, MemoryBuffer &Input) final {
    Module *M = AuxModule.get();

    // Create the new section name, it will consist of the reserved prefix
    // concatenated with the triple.
    std::string SectionName = OFFLOAD_BUNDLER_MAGIC_STR;
    SectionName += CurrentTriple;

    // Create the constant with the content of the section. For the input we are
    // bundling into (the host input), this is just a place-holder, so a single
    // byte is sufficient.
    assert(HostInputIndex != ~0u && "Host input index undefined??");
    Constant *Content;
    if (NumberOfProcessedInputs == HostInputIndex + 1) {
      uint8_t Byte[] = {0};
      Content = ConstantDataArray::get(VMContext, Byte);
    } else
      Content = ConstantDataArray::get(
          VMContext, ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(
                                           Input.getBufferStart()),
                                       Input.getBufferSize()));

    // Create the global in the desired section. We don't want these globals in
    // the symbol table, so we mark them private.
    auto *GV = new GlobalVariable(*M, Content->getType(), /*IsConstant=*/true,
                                  GlobalVariable::PrivateLinkage, Content);
    GV->setSection(SectionName);
  }

bool CodeGenCoverage::parse(MemoryBuffer &Buffer, StringRef BackendName) {
  const char *CurPtr = Buffer.getBufferStart();

  while (CurPtr != Buffer.getBufferEnd()) {
    // Read the backend name from the input.
    const char *LexedBackendName = CurPtr;
    while (*CurPtr++ != 0)
      ;
    if (CurPtr == Buffer.getBufferEnd())
      return false; // Data is invalid, expected rule id's to follow.

    bool IsForThisBackend = BackendName.equals(LexedBackendName);
    while (CurPtr != Buffer.getBufferEnd()) {
      if (std::distance(CurPtr, Buffer.getBufferEnd()) < 8)
        return false; // Data is invalid. Not enough bytes for another rule id.

      uint64_t RuleID = support::endian::read64(CurPtr, support::native);
      CurPtr += 8;

      // ~0ull terminates the rule id list.
      if (RuleID == ~0ull)
        break;

      // Anything else, is recorded or ignored depending on whether it's
      // intended for the backend we're interested in.
      if (IsForThisBackend)
        setCovered(RuleID);
    }
  }

  return true;
}

static void printFile(const sys::Path *err)
{
  std::string ErrMsg;
  ErrMsg.clear();
  MemoryBuffer *buf = MemoryBuffer::getFile(err->c_str(), &ErrMsg);
  errs().write(buf->getBufferStart(), buf->getBufferSize());
  delete buf;
}

bool TextInstrProfReader::hasFormat(const MemoryBuffer &Buffer) {
  // Verify that this really looks like plain ASCII text by checking a
  // 'reasonable' number of characters (up to profile magic size).
  size_t count = std::min(Buffer.getBufferSize(), sizeof(uint64_t));
  StringRef buffer = Buffer.getBufferStart();
  return count == 0 || std::all_of(buffer.begin(), buffer.begin() + count,
    [](char c) { return ::isprint(c) || ::isspace(c); });
}

bool RawInstrProfReader<IntPtrT>::hasFormat(const MemoryBuffer &DataBuffer) {
  if (DataBuffer.getBufferSize() < sizeof(uint64_t))
    return false;
  uint64_t Magic =
    *reinterpret_cast<const uint64_t *>(DataBuffer.getBufferStart());
  return RawInstrProf::getMagic<IntPtrT>() == Magic ||
         sys::getSwappedBytes(RawInstrProf::getMagic<IntPtrT>()) == Magic;
}

/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
/// copying the contents and taking ownership of it.  This has no requirements
/// on EndPtr[0].
MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
                                             StringRef BufferName) {
  MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
  if (!Buf) return 0;
  memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
         InputData.size());
  return Buf;
}

/// Writes out bytes from \p FromFile, starting at \p NextToWrite and ending at
/// \p WriteTo - 1.
void InclusionRewriter::OutputContentUpTo(const MemoryBuffer &FromFile,
                                          unsigned &WriteFrom, unsigned WriteTo,
                                          StringRef EOL, int &Line,
                                          bool EnsureNewline) {
  if (WriteTo <= WriteFrom)
    return;
  OS.write(FromFile.getBufferStart() + WriteFrom, WriteTo - WriteFrom);
  // count lines manually, it's faster than getPresumedLoc()
  Line += std::count(FromFile.getBufferStart() + WriteFrom,
                     FromFile.getBufferStart() + WriteTo, '\n');
  if (EnsureNewline) {
    char LastChar = FromFile.getBufferStart()[WriteTo - 1];
    if (LastChar != '\n' && LastChar != '\r')
      OS << EOL;
  }
  WriteFrom = WriteTo;
}

bool IndexedInstrProfReader::hasFormat(const MemoryBuffer &DataBuffer) {
  if (DataBuffer.getBufferSize() < 8)
    return false;
  using namespace support;
  uint64_t Magic =
      endian::read<uint64_t, little, aligned>(DataBuffer.getBufferStart());
  return Magic == IndexedInstrProf::Magic;
}

/// Writes out bytes from \p FromFile, starting at \p NextToWrite and ending at
/// \p WriteTo - 1.
void InclusionRewriter::OutputContentUpTo(const MemoryBuffer &FromFile,
                                          unsigned &WriteFrom, unsigned WriteTo,
                                          StringRef LocalEOL, int &Line,
                                          bool EnsureNewline) {
  if (WriteTo <= WriteFrom)
    return;
  if (&FromFile == PredefinesBuffer) {
    // Ignore the #defines of the predefines buffer.
    WriteFrom = WriteTo;
    return;
  }

  // If we would output half of a line ending, advance one character to output
  // the whole line ending.  All buffers are null terminated, so looking ahead
  // one byte is safe.
  if (LocalEOL.size() == 2 &&
      LocalEOL[0] == (FromFile.getBufferStart() + WriteTo)[-1] &&
      LocalEOL[1] == (FromFile.getBufferStart() + WriteTo)[0])
    WriteTo++;

  StringRef TextToWrite(FromFile.getBufferStart() + WriteFrom,
                        WriteTo - WriteFrom);

  if (MainEOL == LocalEOL) {
    OS << TextToWrite;
    // count lines manually, it's faster than getPresumedLoc()
    Line += TextToWrite.count(LocalEOL);
    if (EnsureNewline && !TextToWrite.endswith(LocalEOL))
      OS << MainEOL;
  } else {
    // Output the file one line at a time, rewriting the line endings as we go.
    StringRef Rest = TextToWrite;
    while (!Rest.empty()) {
      StringRef LineText;
      std::tie(LineText, Rest) = Rest.split(LocalEOL);
      OS << LineText;
      Line++;
      if (!Rest.empty())
        OS << MainEOL;
    }
    if (TextToWrite.endswith(LocalEOL) || EnsureNewline)
      OS << MainEOL;
  }
  WriteFrom = WriteTo;
}

// Write one member out to the file.
bool
Archive::writeMember(
  const ArchiveMember& member,
  raw_fd_ostream& ARFile,
  std::string* ErrMsg
) {

  uint64_t filepos = ARFile.tell();
  filepos -= 8;

  // Get the data and its size either from the
  // member's in-memory data or directly from the file.
  size_t fSize = member.getSize();
  const char *data = (const char*)member.getData();
  MemoryBuffer *mFile = 0;
  if (!data) {
    ErrorOr<std::unique_ptr<MemoryBuffer> > FileOrErr =
        MemoryBuffer::getFile(member.getPath());
    if (!FileOrErr) {
      if (ErrMsg)
        *ErrMsg = FileOrErr.getError().message();
      return true;
    }
    mFile = FileOrErr.get().release();
    data = mFile->getBufferStart();
    fSize = mFile->getBufferSize();
  }

  int hdrSize = fSize;

  // Compute the fields of the header
  ArchiveMemberHeader Hdr;
  bool writeLongName = fillHeader(member,Hdr,hdrSize);

  // Write header to archive file
  ARFile.write((char*)&Hdr, sizeof(Hdr));

  // Write the long filename if its long
  if (writeLongName) {
    StringRef Name = sys::path::filename(member.getPath());
    ARFile.write(Name.data(), Name.size());
  }

  // Write the (possibly compressed) member's content to the file.
  ARFile.write(data,fSize);

  // Make sure the member is an even length
  if ((ARFile.tell() & 1) == 1)
    ARFile << ARFILE_PAD;

  // Close the mapped file if it was opened
  delete mFile;
  return false;
}

line_iterator::line_iterator(const MemoryBuffer &Buffer, char CommentMarker)
    : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
      CommentMarker(CommentMarker), LineNumber(1),
      CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
                  0) {
    // Ensure that if we are constructed on a non-empty memory buffer that it is
    // a null terminated buffer.
    if (Buffer.getBufferSize()) {
        assert(Buffer.getBufferEnd()[0] == '\0');
        advance();
    }
}

/// GetMessage - Return an SMDiagnostic at the specified location with the
/// specified string.
///
/// @param Type - If non-null, the kind of message (e.g., "error") which is
/// prefixed to the message.
SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
                                   const Twine &Msg,
                                   ArrayRef<SMRange> Ranges) const {

  // First thing to do: find the current buffer containing the specified
  // location.
  int CurBuf = FindBufferContainingLoc(Loc);
  assert(CurBuf != -1 && "Invalid or unspecified location!");

  MemoryBuffer *CurMB = getBufferInfo(CurBuf).Buffer;

  // Scan backward to find the start of the line.
  const char *LineStart = Loc.getPointer();
  while (LineStart != CurMB->getBufferStart() &&
         LineStart[-1] != '\n' && LineStart[-1] != '\r')
    --LineStart;

  // Get the end of the line.
  const char *LineEnd = Loc.getPointer();
  while (LineEnd != CurMB->getBufferEnd() &&
         LineEnd[0] != '\n' && LineEnd[0] != '\r')
    ++LineEnd;
  std::string LineStr(LineStart, LineEnd);

  // Convert any ranges to column ranges that only intersect the line of the
  // location.
  SmallVector<std::pair<unsigned, unsigned>, 4> ColRanges;
  for (unsigned i = 0, e = Ranges.size(); i != e; ++i) {
    SMRange R = Ranges[i];
    if (!R.isValid()) continue;
    
    // If the line doesn't contain any part of the range, then ignore it.
    if (R.Start.getPointer() > LineEnd || R.End.getPointer() < LineStart)
      continue;
   
    // Ignore pieces of the range that go onto other lines.
    if (R.Start.getPointer() < LineStart)
      R.Start = SMLoc::getFromPointer(LineStart);
    if (R.End.getPointer() > LineEnd)
      R.End = SMLoc::getFromPointer(LineEnd);
    
    // Translate from SMLoc ranges to column ranges.
    ColRanges.push_back(std::make_pair(R.Start.getPointer()-LineStart,
                                       R.End.getPointer()-LineStart));
  }
  
  return SMDiagnostic(*this, Loc,
                      CurMB->getBufferIdentifier(), FindLineNumber(Loc, CurBuf),
                      Loc.getPointer()-LineStart, Kind, Msg.str(),
                      LineStr, ColRanges);
}