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 // Record that the input argument INPUT is an achive ARCHIVE.  This is
 183 // called by Read_symbols after finding out the type of the file.
 184
 185 void
 186 Incremental_inputs::report_archive(const Input_argument* input,
 187                                    Archive* archive)
 188 {
 189   Hold_lock hl(*this->lock_);
 190
 191   Input_info info;
 192   info.type = INCREMENTAL_INPUT_ARCHIVE;
 193   info.archive = archive;
 194   inputs_map_.insert(std::make_pair(input, info));
 195 }
 196
 197 // Record that the input argument INPUT is an object OBJ.  This is
 198 // called by Read_symbols after finding out the type of the file.
 199
 200 void
 201 Incremental_inputs::report_object(const Input_argument* input,
 202                                   Object* obj)
 203 {
 204   Hold_lock hl(*this->lock_);
 205
 206   Input_info info;
 207   info.type = (obj->is_dynamic()
 208                ? INCREMENTAL_INPUT_SHARED_LIBRARY
 209                : INCREMENTAL_INPUT_OBJECT);
 210   info.object = obj;
 211   inputs_map_.insert(std::make_pair(input, info));
 212 }
 213
 214 // Record that the input argument INPUT is an script SCRIPT.  This is
 215 // called by read_script after parsing the script and reading the list
 216 // of inputs added by this script.
 217
 218 void
 219 Incremental_inputs::report_script(const Input_argument* input,
 220                                   Script_info* script)
 221 {
 222   Hold_lock hl(*this->lock_);
 223
 224   Input_info info;
 225   info.type = INCREMENTAL_INPUT_SCRIPT;
 226   info.script = script;
 227   inputs_map_.insert(std::make_pair(input, info));
 228 }
 229
 230 // Compute indexes in the order in which the inputs should appear in
 231 // .gnu_incremental_inputs.  This needs to be done after all the
 232 // scripts are parsed.  The function is first called for the command
 233 // line inputs arguments and may call itself recursively for e.g. a
 234 // list of elements of a group or a list of inputs added by a script.
 235 // The [BEGIN; END) interval to analyze and *INDEX is the current
 236 // value of the index (that will be updated).
 237
 238 void
 239 Incremental_inputs::finalize_inputs(
 240     Input_argument_list::const_iterator begin,
 241     Input_argument_list::const_iterator end,
 242     unsigned int* index)
 243 {
 244   for (Input_argument_list::const_iterator p = begin; p != end; ++p)
 245     {
 246       if (p->is_group())
 247         {
 248           finalize_inputs(p->group()->begin(), p->group()->end(), index);
 249           continue;
 250         }
 251
 252       Inputs_info_map::iterator it = inputs_map_.find(&(*p));
 253       // TODO: turn it into an assert when the code will be more stable.
 254       if (it == inputs_map_.end())
 255         {
 256           gold_error("internal error: %s: incremental build info not provided",
 257                      (p->is_file() ? p->file().name() : "[group]"));
 258           continue;
 259         }
 260       Input_info* info = &it->second;
 261       info->index = *index;
 262       (*index)++;
 263       this->strtab_->add(p->file().name(), false, &info->filename_key);
 264       if (info->type == INCREMENTAL_INPUT_SCRIPT)
 265         {
 266           finalize_inputs(info->script->inputs()->begin(),
 267                           info->script->inputs()->end(),
 268                           index);
 269         }
 270     }
 271 }
 272
 273 // Finalize the incremental link information.  Called from
 274 // Layout::finalize.
 275
 276 void
 277 Incremental_inputs::finalize()
 278 {
 279   unsigned int index = 0;
 280   finalize_inputs(this->inputs_->begin(), this->inputs_->end(), &index);
 281
 282   // Sanity check.
 283   for (Inputs_info_map::const_iterator p = inputs_map_.begin();
 284        p != inputs_map_.end();
 285        ++p)
 286     {
 287       gold_assert(p->second.filename_key != 0);
 288     }
 289
 290   this->strtab_->set_string_offsets();
 291 }
 292
 293 // Create the content of the .gnu_incremental_inputs section.
 294
 295 Output_section_data*
 296 Incremental_inputs::create_incremental_inputs_section_data()
 297 {
 298   switch (parameters->size_and_endianness())
 299     {
 300 #ifdef HAVE_TARGET_32_LITTLE
 301     case Parameters::TARGET_32_LITTLE:
 302       return this->sized_create_inputs_section_data<32, false>();
 303 #endif
 304 #ifdef HAVE_TARGET_32_BIG
 305     case Parameters::TARGET_32_BIG:
 306       return this->sized_create_inputs_section_data<32, true>();
 307 #endif
 308 #ifdef HAVE_TARGET_64_LITTLE
 309     case Parameters::TARGET_64_LITTLE:
 310       return this->sized_create_inputs_section_data<64, false>();
 311 #endif
 312 #ifdef HAVE_TARGET_64_BIG
 313     case Parameters::TARGET_64_BIG:
 314       return this->sized_create_inputs_section_data<64, true>();
 315 #endif
 316     default:
 317       gold_unreachable();
 318     }
 319 }
 320
 321 // Sized creation of .gnu_incremental_inputs section.
 322
 323 template<int size, bool big_endian>
 324 Output_section_data*
 325 Incremental_inputs::sized_create_inputs_section_data()
 326 {
 327   const int entry_size =
 328       Incremental_inputs_entry_write<size, big_endian>::data_size;
 329   const int header_size =
 330       Incremental_inputs_header_write<size, big_endian>::data_size;
 331
 332   unsigned int sz = header_size + entry_size * this->inputs_map_.size();
 333   unsigned char* buffer = new unsigned char[sz];
 334   unsigned char* inputs_base = buffer + header_size;
 335
 336   Incremental_inputs_header_write<size, big_endian> header_writer(buffer);
 337   gold_assert(this->command_line_key_ > 0);
 338   int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_);
 339
 340   header_writer.put_version(INCREMENTAL_LINK_VERSION);
 341   header_writer.put_input_file_count(this->inputs_map_.size());
 342   header_writer.put_command_line_offset(cmd_offset);
 343   header_writer.put_reserved(0);
 344
 345   for (Inputs_info_map::const_iterator it = this->inputs_map_.begin();
 346        it != this->inputs_map_.end();
 347        ++it)
 348     {
 349       gold_assert(it->second.index < this->inputs_map_.size());
 350
 351       unsigned char* entry_buffer =
 352           inputs_base + it->second.index * entry_size;
 353       Incremental_inputs_entry_write<size, big_endian> entry(entry_buffer);
 354       int filename_offset =
 355           this->strtab_->get_offset_from_key(it->second.filename_key);
 356       entry.put_filename_offset(filename_offset);
 357       // TODO: add per input data and timestamp.  Currently we store
 358       // an out-of-bounds offset for future version of gold to reject
 359       // such an incremental_inputs section.
 360       entry.put_data_offset(0xffffffff);
 361       entry.put_timestamp_sec(0);
 362       entry.put_timestamp_usec(0);
 363       entry.put_input_type(it->second.type);
 364       entry.put_reserved(0);
 365     }
 366
 367   return new Output_data_const_buffer(buffer, sz, 8,
 368                                       "** incremental link inputs list");
 369 }
 370
 371 } // End namespace gold.