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      1 // compressed_output.h -- compressed output sections for gold  -*- C++ -*-
      2 
      3 // Copyright (C) 2007-2016 Free Software Foundation, Inc.
      4 // Written by Ian Lance Taylor <iant (at) 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 // Read the compression header of a compressed debug section and return
     41 // the uncompressed size.
     42 
     43 extern uint64_t
     44 get_uncompressed_size(const unsigned char*, section_size_type);
     45 
     46 // Decompress a compressed debug section directly into the output file.
     47 
     48 extern bool
     49 decompress_input_section(const unsigned char*, unsigned long, unsigned char*,
     50 			 unsigned long, int, bool, elfcpp::Elf_Xword);
     51 
     52 // This is used for a section whose data should be compressed.  It is
     53 // a regular Output_section which computes its contents into a buffer
     54 // and then postprocesses it.
     55 
     56 class Output_compressed_section : public Output_section
     57 {
     58  public:
     59   Output_compressed_section(const General_options* options,
     60 			    const char* name, elfcpp::Elf_Word flags,
     61 			    elfcpp::Elf_Xword type)
     62     : Output_section(name, flags, type),
     63       options_(options)
     64   { this->set_requires_postprocessing(); }
     65 
     66  protected:
     67   // Set the final data size.
     68   void
     69   set_final_data_size();
     70 
     71   // Write out the compressed contents.
     72   void
     73   do_write(Output_file*);
     74 
     75  private:
     76   // The options--this includes the compression type.
     77   const General_options* options_;
     78   // The compressed data.
     79   unsigned char* data_;
     80   // The new section name if we do compress.
     81   std::string new_section_name_;
     82 };
     83 
     84 } // End namespace gold.
     85 
     86 #endif // !defined(GOLD_COMPRESSED_OUTPUT_H)
     87