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[/] [open8_urisc/] [trunk/] [gnu/] [binutils/] [gold/] [compressed_output.cc] - Blame information for rev 53

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1 27 khays
// compressed_output.cc -- manage compressed debug sections for gold
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// Copyright 2007, 2008, 2010 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#ifdef HAVE_ZLIB_H
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#include <zlib.h>
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#endif
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#include "parameters.h"
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#include "options.h"
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#include "compressed_output.h"
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namespace gold
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{
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#ifdef HAVE_ZLIB_H
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// Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE.  Returns true
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// if it successfully compressed, false if it failed for any reason
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// (including not having zlib support in the library).  If it returns
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// true, it allocates memory for the compressed data using new, and
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// sets *COMPRESSED_DATA and *COMPRESSED_SIZE to appropriate values.
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// It also writes a header before COMPRESSED_DATA: 4 bytes saying
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// "ZLIB", and 8 bytes indicating the uncompressed size, in big-endian
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// order.
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static bool
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zlib_compress(const unsigned char* uncompressed_data,
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              unsigned long uncompressed_size,
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              unsigned char** compressed_data,
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              unsigned long* compressed_size)
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{
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  const int header_size = 12;
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  *compressed_size = uncompressed_size + uncompressed_size / 1000 + 128;
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  *compressed_data = new unsigned char[*compressed_size + header_size];
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  int compress_level;
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  if (parameters->options().optimize() >= 1)
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    compress_level = 9;
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  else
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    compress_level = 1;
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  int rc = compress2(reinterpret_cast<Bytef*>(*compressed_data) + header_size,
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                     compressed_size,
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                     reinterpret_cast<const Bytef*>(uncompressed_data),
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                     uncompressed_size,
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                     compress_level);
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  if (rc == Z_OK)
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    {
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      memcpy(*compressed_data, "ZLIB", 4);
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      elfcpp::Swap_unaligned<64, true>::writeval(*compressed_data + 4,
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                                                 uncompressed_size);
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      *compressed_size += header_size;
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      return true;
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    }
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  else
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    {
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      delete[] *compressed_data;
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      *compressed_data = NULL;
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      return false;
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    }
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}
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// Decompress COMPRESSED_DATA of size COMPRESSED_SIZE, into a buffer
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// UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE.  Returns TRUE if it
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// decompressed successfully, false if it failed.  The buffer, of
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// appropriate size, is provided by the caller, and is typically part
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// of the memory-mapped output file.
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static bool
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zlib_decompress(const unsigned char* compressed_data,
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                unsigned long compressed_size,
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                unsigned char* uncompressed_data,
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                unsigned long uncompressed_size)
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{
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  z_stream strm;
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  int rc;
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  /* It is possible the section consists of several compressed
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     buffers concatenated together, so we uncompress in a loop.  */
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  strm.zalloc = NULL;
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  strm.zfree = NULL;
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  strm.opaque = NULL;
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  strm.avail_in = compressed_size;
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  strm.next_in = const_cast<Bytef*>(compressed_data);
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  strm.avail_out = uncompressed_size;
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  rc = inflateInit(&strm);
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  while (strm.avail_in > 0)
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    {
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      if (rc != Z_OK)
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        return false;
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      strm.next_out = ((Bytef*) uncompressed_data
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                       + (uncompressed_size - strm.avail_out));
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      rc = inflate(&strm, Z_FINISH);
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      if (rc != Z_STREAM_END)
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        return false;
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      rc = inflateReset(&strm);
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    }
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  rc = inflateEnd(&strm);
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  if (rc != Z_OK || strm.avail_out != 0)
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    return false;
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  return true;
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}
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#else // !defined(HAVE_ZLIB_H)
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static bool
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zlib_compress(const unsigned char*, unsigned long,
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              unsigned char**, unsigned long*)
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{
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  return false;
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}
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static bool
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zlib_decompress(const unsigned char*, unsigned long,
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                unsigned char*, unsigned long)
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{
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  return false;
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}
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#endif // !defined(HAVE_ZLIB_H)
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// Read the compression header of a compressed debug section and return
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// the uncompressed size.
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uint64_t
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get_uncompressed_size(const unsigned char* compressed_data,
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                      section_size_type compressed_size)
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{
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  const unsigned int zlib_header_size = 12;
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  /* Verify the compression header.  Currently, we support only zlib
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     compression, so it should be "ZLIB" followed by the uncompressed
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     section size, 8 bytes in big-endian order.  */
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  if (compressed_size >= zlib_header_size
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      && strncmp(reinterpret_cast<const char*>(compressed_data),
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                 "ZLIB", 4) == 0)
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    return elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
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  return -1ULL;
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}
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// Decompress a compressed debug section directly into the output file.
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bool
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decompress_input_section(const unsigned char* compressed_data,
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                         unsigned long compressed_size,
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                         unsigned char* uncompressed_data,
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                         unsigned long uncompressed_size)
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{
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  const unsigned int zlib_header_size = 12;
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  /* Verify the compression header.  Currently, we support only zlib
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     compression, so it should be "ZLIB" followed by the uncompressed
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     section size, 8 bytes in big-endian order.  */
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  if (compressed_size >= zlib_header_size
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      && strncmp(reinterpret_cast<const char*>(compressed_data),
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                 "ZLIB", 4) == 0)
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    {
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      unsigned long uncompressed_size_check =
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          elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
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      gold_assert(uncompressed_size_check == uncompressed_size);
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      return zlib_decompress(compressed_data + zlib_header_size,
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                             compressed_size - zlib_header_size,
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                             uncompressed_data,
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                             uncompressed_size);
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    }
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  return false;
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}
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// Class Output_compressed_section.
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// Set the final data size of a compressed section.  This is where
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// we actually compress the section data.
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void
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Output_compressed_section::set_final_data_size()
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{
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  off_t uncompressed_size = this->postprocessing_buffer_size();
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  // (Try to) compress the data.
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  unsigned long compressed_size;
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  unsigned char* uncompressed_data = this->postprocessing_buffer();
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  // At this point the contents of all regular input sections will
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  // have been copied into the postprocessing buffer, and relocations
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  // will have been applied.  Now we need to copy in the contents of
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  // anything other than a regular input section.
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  this->write_to_postprocessing_buffer();
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  bool success = false;
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  if (strcmp(this->options_->compress_debug_sections(), "zlib") == 0)
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    success = zlib_compress(uncompressed_data, uncompressed_size,
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                            &this->data_, &compressed_size);
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  if (success)
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    {
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      // This converts .debug_foo to .zdebug_foo
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      this->new_section_name_ = std::string(".z") + (this->name() + 1);
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      this->set_name(this->new_section_name_.c_str());
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      this->set_data_size(compressed_size);
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    }
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  else
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    {
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      gold_warning(_("not compressing section data: zlib error"));
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      gold_assert(this->data_ == NULL);
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      this->set_data_size(uncompressed_size);
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    }
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}
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// Write out a compressed section.  If we couldn't compress, we just
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// write it out as normal, uncompressed data.
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void
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Output_compressed_section::do_write(Output_file* of)
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{
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  off_t offset = this->offset();
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  off_t data_size = this->data_size();
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  unsigned char* view = of->get_output_view(offset, data_size);
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  if (this->data_ == NULL)
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    memcpy(view, this->postprocessing_buffer(), data_size);
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  else
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    memcpy(view, this->data_, data_size);
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  of->write_output_view(offset, data_size, view);
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}
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} // End namespace gold.

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