gold/reduced_debug_output.h

   1 // reduced_debug_output.h -- reduce debugging information  -*- C++ -*-
   2
   3 // Copyright (C) 2008-2020 Free Software Foundation, Inc.
   4 // Written by Caleb Howe <cshowe@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 // Reduce the size of the debug sections by emitting only debug line number
  24 // information.  We still need to emit skeleton debug_info and debug_abbrev
  25 // sections for standard tools to parse the debug information correctly.  These
  26 // classes remove all debug information entries from the .debug_info section
  27 // except for those describing compilation units as these DIEs contain
  28 // references to the debug line information needed by most parsers.
  29
  30 #ifndef GOLD_REDUCED_DEBUG_OUTPUT_H
  31 #define GOLD_REDUCED_DEBUG_OUTPUT_H
  32
  33 #include <map>
  34 #include <utility>
  35 #include <vector>
  36
  37 #include "output.h"
  38
  39 namespace gold
  40 {
  41
  42 class Output_reduced_debug_abbrev_section : public Output_section
  43 {
  44  public:
  45   Output_reduced_debug_abbrev_section(const char* name, elfcpp::Elf_Word flags,
  46                                       elfcpp::Elf_Xword type)
  47     : Output_section(name, flags, type), sized_(false),
  48       abbrev_count_(0), failed_(false)
  49   { this->set_requires_postprocessing(); }
  50
  51   unsigned char* get_new_abbrev(uint64_t* abbrev_number,
  52                                 uint64_t abbrev_offset);
  53
  54  protected:
  55   // Set the final data size.
  56   void
  57   set_final_data_size();
  58
  59   // Write out the new debug abbreviations
  60   void
  61   do_write(Output_file*);
  62
  63  private:
  64   void
  65   failed(std::string reason)
  66   {
  67     gold_warning("%s", reason.c_str());
  68     failed_ = true;
  69   }
  70
  71   // The reduced debug abbreviations
  72   std::vector<unsigned char> data_;
  73
  74   // We map the abbreviation table offset and abbreviation number of the
  75   // old abbreviation to the number and size of the new abbreviation.
  76   std::map<std::pair<uint64_t, uint64_t>,
  77            std::pair<uint64_t, uint64_t> > abbrev_mapping_;
  78
  79   bool sized_;
  80
  81   // The count of abbreviations in the output data
  82   int abbrev_count_;
  83
  84   // Whether or not the debug reduction has failed for any reason
  85   bool failed_;
  86 };
  87
  88 class Output_reduced_debug_info_section : public Output_section
  89 {
  90  public:
  91   Output_reduced_debug_info_section(const char* name, elfcpp::Elf_Word flags,
  92                                     elfcpp::Elf_Xword type)
  93     : Output_section(name, flags, type), failed_(false)
  94   { this->set_requires_postprocessing(); }
  95
  96   void
  97   set_abbreviations(Output_reduced_debug_abbrev_section* abbrevs)
  98   { associated_abbrev_ = abbrevs; }
  99
 100  protected:
 101   // Set the final data size.
 102   void
 103   set_final_data_size();
 104
 105   // Write out the new debug info
 106   void
 107   do_write(Output_file*);
 108
 109  private:
 110   void
 111   failed(std::string reason)
 112   {
 113     gold_warning("%s", reason.c_str());
 114     this->failed_ = true;
 115   }
 116
 117   // Given a pointer to the beginning of a die and the beginning of the
 118   // associated abbreviation fills in die_end with the end of the information
 119   // entry.  If successful returns true.  Get_die_end also takes a pointer to
 120   // the end of the buffer containing the die. If die_end would be beyond the
 121   // end of the buffer, or if an unsupported dwarf form is encountered returns
 122   // false.
 123   bool
 124   get_die_end(unsigned char* die, unsigned char* abbrev,
 125               unsigned char** die_end, unsigned char* buffer_end,
 126               int address_size, bool is64);
 127
 128   // The reduced debug info
 129   std::vector<unsigned char> data_;
 130
 131   // Each debug info section needs to be associated with a debug abbrev section
 132   Output_reduced_debug_abbrev_section* associated_abbrev_;
 133
 134   // Whether or not the debug reduction has failed for any reason
 135   bool failed_;
 136 };
 137
 138 } // End namespace gold.
 139
 140 #endif // !defined(GOLD_REDUCED_DEBUG_OUTPUT_H)