gold/incremental.cc

   1 // inremental.cc -- incremental linking support for gold
   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 #include "gold.h"
  24 #include "elfcpp.h"
  25 #include "output.h"
  26 #include "incremental.h"
  27
  28 using elfcpp::Convert;
  29
  30 namespace gold {
  31
  32 // Version information. Will change frequently during the development, later
  33 // we could think about backward (and forward?) compatibility.
  34 const int INCREMENTAL_LINK_VERSION = 1;
  35
  36 namespace internal {
  37
  38 // Header of the .gnu_incremental_input section.
  39 struct Incremental_inputs_header_data
  40 {
  41   // Incremental linker version.
  42   elfcpp::Elf_Word version;
  43
  44   // Numer of input files in the link.
  45   elfcpp::Elf_Word input_file_count;
  46
  47   // Offset of command line options in .gnu_incremental_strtab.
  48   elfcpp::Elf_Word command_line_offset;
  49
  50   // Padding.
  51   elfcpp::Elf_Word reserved;
  52 };
  53
  54 // Data stored in .gnu_incremental_input after the header for each of the
  55 // Incremental_input_header_data::input_file_count input entries.
  56 struct Incremental_inputs_entry_data
  57 {
  58   // Offset of file name in .gnu_incremental_strtab section.
  59   elfcpp::Elf_Word filename_offset;
  60
  61   // Offset of data in .gnu_incremental_input.
  62   elfcpp::Elf_Word data_offset;
  63
  64   // Timestamp (in seconds).
  65   elfcpp::Elf_Xword timestamp_sec;
  66
  67   // Nano-second part of timestamp (if supported).
  68   elfcpp::Elf_Word timestamp_usec;
  69
  70   // Type of the input entry.
  71   elfcpp::Elf_Half input_type;
  72
  73   // Padding.
  74   elfcpp::Elf_Half reserved;
  75 };
  76
  77 }
  78
  79 // Accessors.
  80
  81 // See internal::Incremental_input_header for fields descriptions.
  82 template<int size, bool big_endian>
  83 class Incremental_inputs_header_write
  84 {
  85  public:
  86   Incremental_inputs_header_write(unsigned char *p)
  87     : p_(reinterpret_cast<internal::Incremental_inputs_header_data*>(p))
  88   { }
  89
  90   static const int data_size = sizeof(internal::Incremental_inputs_header_data);
  91
  92   void
  93   put_version(elfcpp::Elf_Word v)
  94   { this->p_->version = Convert<32, big_endian>::convert_host(v); }
  95
  96   void
  97   put_input_file_count(elfcpp::Elf_Word v)
  98   { this->p_->input_file_count = Convert<32, big_endian>::convert_host(v); }
  99
 100   void
 101   put_command_line_offset(elfcpp::Elf_Word v)
 102   { this->p_->command_line_offset = Convert<32, big_endian>::convert_host(v); }
 103
 104   void
 105   put_reserved(elfcpp::Elf_Word v)
 106   { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
 107
 108  private:
 109   internal::Incremental_inputs_header_data* p_;
 110 };
 111
 112 // See internal::Incremental_input_entry for fields descriptions.
 113 template<int size, bool big_endian>
 114 class Incremental_inputs_entry_write
 115 {
 116  public:
 117   Incremental_inputs_entry_write(unsigned char *p)
 118     : p_(reinterpret_cast<internal::Incremental_inputs_entry_data*>(p))
 119   { }
 120
 121   static const int data_size = sizeof(internal::Incremental_inputs_entry_data);
 122
 123   void
 124   put_filename_offset(elfcpp::Elf_Word v)
 125   { this->p_->filename_offset = Convert<32, big_endian>::convert_host(v); }
 126
 127   void
 128   put_data_offset(elfcpp::Elf_Word v)
 129   { this->p_->data_offset = Convert<32, big_endian>::convert_host(v); }
 130
 131   void
 132   put_timestamp_sec(elfcpp::Elf_Word v)
 133   { this->p_->timestamp_sec = Convert<32, big_endian>::convert_host(v); }
 134
 135   void
 136   put_timestamp_usec(elfcpp::Elf_Word v)
 137   { this->p_->timestamp_usec = Convert<32, big_endian>::convert_host(v); }
 138
 139   void
 140   put_input_type(elfcpp::Elf_Word v)
 141   { this->p_->input_type = Convert<32, big_endian>::convert_host(v); }
 142
 143   void
 144   put_reserved(elfcpp::Elf_Word v)
 145   { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
 146
 147  private:
 148   internal::Incremental_inputs_entry_data* p_;
 149 };
 150
 151 // Add the command line to the string table, setting
 152 // command_line_key_.  In incremental builds, the command line is
 153 // stored in .gnu_incremental_inputs so that the next linker run can
 154 // check if the command line options didn't change.
 155
 156 void
 157 Incremental_inputs::report_command_line(int argc, const char* const* argv)
 158 {
 159   // Always store 'gold' as argv[0] to avoid a full relink if the user used a
 160   // different path to the linker.
 161   std::string args("gold");
 162   // Copied from collect_argv in main.cc.
 163   for (int i = 1; i < argc; ++i)
 164     {
 165       args.append(" '");
 166       // Now append argv[i], but with all single-quotes escaped
 167       const char* argpos = argv[i];
 168       while (1)
 169         {
 170           const int len = strcspn(argpos, "'");
 171           args.append(argpos, len);
 172           if (argpos[len] == '\0')
 173             break;
 174           args.append("'\"'\"'");
 175           argpos += len + 1;
 176         }
 177       args.append("'");
 178     }
 179   this->strtab_->add(args.c_str(), true, &this->command_line_key_);
 180 }
 181
 182 // Finalize the incremental link information.  Called from
 183 // Layout::finalize.
 184
 185 void
 186 Incremental_inputs::finalize()
 187 {
 188   this->strtab_->set_string_offsets();
 189 }
 190
 191 // Create the content of the .gnu_incremental_inputs section.
 192
 193 Output_section_data*
 194 Incremental_inputs::create_incremental_inputs_section_data()
 195 {
 196   switch (parameters->size_and_endianness())
 197     {
 198 #ifdef HAVE_TARGET_32_LITTLE
 199     case Parameters::TARGET_32_LITTLE:
 200       return this->sized_create_inputs_section_data<32, false>();
 201 #endif
 202 #ifdef HAVE_TARGET_32_BIG
 203     case Parameters::TARGET_32_BIG:
 204       return this->sized_create_inputs_section_data<32, true>();
 205 #endif
 206 #ifdef HAVE_TARGET_64_LITTLE
 207     case Parameters::TARGET_64_LITTLE:
 208       return this->sized_create_inputs_section_data<64, false>();
 209 #endif
 210 #ifdef HAVE_TARGET_64_BIG
 211     case Parameters::TARGET_64_BIG:
 212       return this->sized_create_inputs_section_data<64, true>();
 213 #endif
 214     default:
 215       gold_unreachable();
 216     }
 217 }
 218
 219 // Sized creation of .gnu_incremental_inputs section.
 220
 221 template<int size, bool big_endian>
 222 Output_section_data*
 223 Incremental_inputs::sized_create_inputs_section_data()
 224 {
 225   unsigned int sz =
 226       Incremental_inputs_header_write<size, big_endian>::data_size;
 227   unsigned char* buffer = new unsigned char[sz];
 228   Incremental_inputs_header_write<size, big_endian> header_writer(buffer);
 229
 230   gold_assert(this->command_line_key_ > 0);
 231   int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_);
 232
 233   header_writer.put_version(INCREMENTAL_LINK_VERSION);
 234   header_writer.put_input_file_count(0);   // TODO: store input files data.
 235   header_writer.put_command_line_offset(cmd_offset);
 236   header_writer.put_reserved(0);
 237
 238   return new Output_data_const_buffer(buffer, sz, 8,
 239       "** incremental link inputs list");
 240 }
 241
 242 } // End namespace gold.