gold/incremental.h

   1 // inremental.h -- incremental linking support for gold   -*- C++ -*-
   2
   3 // Copyright 2009 Free Software Foundation, Inc.
   4 // Written by Mikolaj Zalewski <mikolajz@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 #ifndef GOLD_INCREMENTAL_H
  24 #define GOLD_INCREMENTAL_H
  25
  26 #include <map>
  27 #include <vector>
  28
  29 #include "stringpool.h"
  30 #include "workqueue.h"
  31 #include "fileread.h"
  32
  33 namespace gold
  34 {
  35
  36 class Archive;
  37 class Input_argument;
  38 class Incremental_inputs_checker;
  39 class Object;
  40 class Output_section_data;
  41
  42 // Incremental input type as stored in .gnu_incremental_inputs.
  43
  44 enum Incremental_input_type
  45 {
  46   INCREMENTAL_INPUT_INVALID = 0,
  47   INCREMENTAL_INPUT_OBJECT = 1,
  48   INCREMENTAL_INPUT_ARCHIVE = 2,
  49   INCREMENTAL_INPUT_SHARED_LIBRARY = 3,
  50   INCREMENTAL_INPUT_SCRIPT = 4
  51 };
  52
  53 // Code invoked early during an incremental link that checks what files need
  54 // to be relinked.
  55 class Incremental_checker
  56 {
  57  public:
  58   Incremental_checker(const char* output_name)
  59     : output_name_(output_name)
  60   { }
  61
  62   // Analyzes the output file to check if incremental linking is possible and
  63   // what files needs to be relinked.
  64   bool
  65   can_incrementally_link_output_file();
  66
  67  private:
  68   const char* output_name_;
  69 };
  70
  71 // This class contains the information needed during an incremental
  72 // build about the inputs necessary to build the .gnu_incremental_inputs.
  73 class Incremental_inputs
  74 {
  75  public:
  76   Incremental_inputs()
  77     : lock_(new Lock()), inputs_(NULL), command_line_key_(0),
  78       strtab_(new Stringpool())
  79   { }
  80   ~Incremental_inputs() { delete this->strtab_; }
  81
  82   // Record the command line.
  83   void
  84   report_command_line(int argc, const char* const* argv);
  85
  86   // Record the input arguments obtained from parsing the command line.
  87   void
  88   report_inputs(const Input_arguments& inputs)
  89   { this->inputs_ = &inputs; }
  90
  91   // Record that the input argument INPUT is an archive ARCHIVE.
  92   void
  93   report_archive(const Input_argument* input, Archive* archive);
  94
  95   // Record that the input argument INPUT is to an object OBJ.
  96   void
  97   report_object(const Input_argument* input, Object* obj);
  98
  99   // Record that the input argument INPUT is to an script SCRIPT.
 100   void
 101   report_script(const Input_argument* input, Timespec mtime,
 102                 Script_info* script);
 103
 104   // Prepare for layout.  Called from Layout::finalize.
 105   void
 106   finalize();
 107
 108   // Create the content of the .gnu_incremental_inputs section.
 109   Output_section_data*
 110   create_incremental_inputs_section_data();
 111
 112   // Return the .gnu_incremental_strtab stringpool.
 113   Stringpool*
 114   get_stringpool()
 115   { return this->strtab_; }
 116
 117  private:
 118   // Code for each of the four possible variants of create_inputs_section_data.
 119   template<int size, bool big_endian>
 120   Output_section_data*
 121   sized_create_inputs_section_data();
 122
 123   // Compute indexes in the order in which the inputs should appear in
 124   // .gnu_incremental_inputs and put file names to the stringtable.
 125   // This needs to be done after all the scripts are parsed.
 126
 127   void
 128   finalize_inputs(Input_argument_list::const_iterator begin,
 129                   Input_argument_list::const_iterator end,
 130                   unsigned int* index);
 131
 132   // Additional data about an input needed for an incremental link.
 133   // None of these pointers is owned by the structure.
 134   struct Input_info
 135   {
 136     Input_info()
 137       : type(INCREMENTAL_INPUT_INVALID), archive(NULL), filename_key(0),
 138         index(0)
 139     { }
 140
 141     // Type of the file pointed by this argument.
 142     Incremental_input_type type;
 143
 144     union
 145     {
 146       // Present if type == INCREMENTAL_INPUT_ARCHIVE.
 147       Archive* archive;
 148
 149       // Present if type == INCREMENTAL_INPUT_OBJECT or
 150       // INCREMENTAL_INPUT_SHARED_LIBRARY.
 151       Object* object;
 152
 153       // Present if type == INCREMENTAL_INPUT_SCRIPT.
 154       Script_info* script;
 155     };
 156
 157     // Key of the filename string in the section stringtable.
 158     Stringpool::Key filename_key;
 159
 160     // Position of the entry information in the output section.
 161     unsigned int index;
 162
 163     // Last modification time of the file.
 164     Timespec mtime;
 165   };
 166
 167   typedef std::map<const Input_argument*, Input_info> Inputs_info_map;
 168
 169   // A lock guarding access to inputs_ during the first phase of linking, when
 170   // report_ function may be called from multiple threads.
 171   Lock* lock_;
 172
 173   // The list of input arguments obtained from parsing the command line.
 174   const Input_arguments* inputs_;
 175
 176   // A map containing additional information about the input elements.
 177   Inputs_info_map inputs_map_;
 178
 179   // The key of the command line string in the string pool.
 180   Stringpool::Key command_line_key_;
 181   // The .gnu_incremental_strtab string pool associated with the
 182   // .gnu_incremental_inputs.
 183   Stringpool* strtab_;
 184 };
 185
 186 } // End namespace gold.
 187
 188 #endif // !defined(GOLD_INCREMENTAL_H)