gold/compressed_output.h

   1 // compressed_output.h -- compressed output sections for gold  -*- C++ -*-
   2
   3 // Copyright 2007, 2008 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 // We support compressing .debug_* sections on output.  (And,
  24 // potentially one day, other sections.)  This is a form of
  25 // relaxation.  This file adds support for merging and emitting the
  26 // compressed sections.
  27
  28 #ifndef GOLD_COMPRESSED_OUTPUT_H
  29 #define GOLD_COMPRESSED_OUTPUT_H
  30
  31 #include <string>
  32
  33 #include "output.h"
  34
  35 namespace gold
  36 {
  37
  38 class General_options;
  39
  40 // This is used for a section whose data should be compressed.  It is
  41 // a regular Output_section which computes its contents into a buffer
  42 // and then postprocesses it.
  43
  44 class Output_compressed_section : public Output_section
  45 {
  46  public:
  47   Output_compressed_section(const General_options* options,
  48                             const char* name, elfcpp::Elf_Word flags,
  49                             elfcpp::Elf_Xword type)
  50     : Output_section(name, flags, type),
  51       options_(options)
  52   { this->set_requires_postprocessing(); }
  53
  54  protected:
  55   // Set the final data size.
  56   void
  57   set_final_data_size();
  58
  59   // Write out the compressed contents.
  60   void
  61   do_write(Output_file*);
  62
  63  private:
  64   // The options--this includes the compression type.
  65   const General_options* options_;
  66   // The compressed data.
  67   unsigned char* data_;
  68   // The new section name if we do compress.
  69   std::string new_section_name_;
  70 };
  71
  72 } // End namespace gold.
  73
  74 #endif // !defined(GOLD_COMPRESSED_OUTPUT_H)