contrib/binutils-2.21/gold/incremental.cc

   1 // inremental.cc -- incremental linking support for gold
   2
   3 // Copyright 2009, 2010 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
  25 #include <cstdarg>
  26 #include "libiberty.h"
  27
  28 #include "elfcpp.h"
  29 #include "output.h"
  30 #include "symtab.h"
  31 #include "incremental.h"
  32 #include "archive.h"
  33 #include "output.h"
  34 #include "target-select.h"
  35 #include "target.h"
  36
  37 namespace gold {
  38
  39 // Version information. Will change frequently during the development, later
  40 // we could think about backward (and forward?) compatibility.
  41 const unsigned int INCREMENTAL_LINK_VERSION = 1;
  42
  43 // This class manages the .gnu_incremental_inputs section, which holds
  44 // the header information, a directory of input files, and separate
  45 // entries for each input file.
  46
  47 template<int size, bool big_endian>
  48 class Output_section_incremental_inputs : public Output_section_data
  49 {
  50  public:
  51   Output_section_incremental_inputs(const Incremental_inputs* inputs,
  52                                     const Symbol_table* symtab)
  53     : Output_section_data(size / 8), inputs_(inputs), symtab_(symtab)
  54   { }
  55
  56  protected:
  57   // Set the final data size.
  58   void
  59   set_final_data_size();
  60
  61   // Write the data to the file.
  62   void
  63   do_write(Output_file*);
  64
  65   // Write to a map file.
  66   void
  67   do_print_to_mapfile(Mapfile* mapfile) const
  68   { mapfile->print_output_data(this, _("** incremental_inputs")); }
  69
  70  private:
  71   // Write the section header.
  72   unsigned char*
  73   write_header(unsigned char* pov, unsigned int input_file_count,
  74                section_offset_type command_line_offset);
  75
  76   // Write the input file entries.
  77   unsigned char*
  78   write_input_files(unsigned char* oview, unsigned char* pov,
  79                     Stringpool* strtab);
  80
  81   // Write the supplemental information blocks.
  82   unsigned char*
  83   write_info_blocks(unsigned char* oview, unsigned char* pov,
  84                     Stringpool* strtab, unsigned int* global_syms,
  85                     unsigned int global_sym_count);
  86
  87   // Write the contents of the .gnu_incremental_symtab section.
  88   void
  89   write_symtab(unsigned char* pov, unsigned int* global_syms,
  90                unsigned int global_sym_count);
  91
  92   // Write the contents of the .gnu_incremental_got_plt section.
  93   void
  94   write_got_plt(unsigned char* pov, off_t view_size);
  95
  96   // Typedefs for writing the data to the output sections.
  97   typedef elfcpp::Swap<size, big_endian> Swap;
  98   typedef elfcpp::Swap<16, big_endian> Swap16;
  99   typedef elfcpp::Swap<32, big_endian> Swap32;
 100   typedef elfcpp::Swap<64, big_endian> Swap64;
 101
 102   // Sizes of various structures.
 103   static const int sizeof_addr = size / 8;
 104   static const int header_size = 16;
 105   static const int input_entry_size = 24;
 106
 107   // The Incremental_inputs object.
 108   const Incremental_inputs* inputs_;
 109
 110   // The symbol table.
 111   const Symbol_table* symtab_;
 112 };
 113
 114 // Inform the user why we don't do an incremental link.  Not called in
 115 // the obvious case of missing output file.  TODO: Is this helpful?
 116
 117 void
 118 vexplain_no_incremental(const char* format, va_list args)
 119 {
 120   char* buf = NULL;
 121   if (vasprintf(&buf, format, args) < 0)
 122     gold_nomem();
 123   gold_info(_("the link might take longer: "
 124               "cannot perform incremental link: %s"), buf);
 125   free(buf);
 126 }
 127
 128 void
 129 explain_no_incremental(const char* format, ...)
 130 {
 131   va_list args;
 132   va_start(args, format);
 133   vexplain_no_incremental(format, args);
 134   va_end(args);
 135 }
 136
 137 // Report an error.
 138
 139 void
 140 Incremental_binary::error(const char* format, ...) const
 141 {
 142   va_list args;
 143   va_start(args, format);
 144   // Current code only checks if the file can be used for incremental linking,
 145   // so errors shouldn't fail the build, but only result in a fallback to a
 146   // full build.
 147   // TODO: when we implement incremental editing of the file, we may need a
 148   // flag that will cause errors to be treated seriously.
 149   vexplain_no_incremental(format, args);
 150   va_end(args);
 151 }
 152
 153 // Find the .gnu_incremental_inputs section and related sections.
 154
 155 template<int size, bool big_endian>
 156 bool
 157 Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_sections(
 158     unsigned int* p_inputs_shndx,
 159     unsigned int* p_symtab_shndx,
 160     unsigned int* p_relocs_shndx,
 161     unsigned int* p_got_plt_shndx,
 162     unsigned int* p_strtab_shndx)
 163 {
 164   unsigned int inputs_shndx =
 165       this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_INPUTS);
 166   if (inputs_shndx == elfcpp::SHN_UNDEF)  // Not found.
 167     return false;
 168
 169   unsigned int symtab_shndx =
 170       this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_SYMTAB);
 171   if (symtab_shndx == elfcpp::SHN_UNDEF)  // Not found.
 172     return false;
 173   if (this->elf_file_.section_link(symtab_shndx) != inputs_shndx)
 174     return false;
 175
 176   unsigned int relocs_shndx =
 177       this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_RELOCS);
 178   if (relocs_shndx == elfcpp::SHN_UNDEF)  // Not found.
 179     return false;
 180   if (this->elf_file_.section_link(relocs_shndx) != inputs_shndx)
 181     return false;
 182
 183   unsigned int got_plt_shndx =
 184       this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT);
 185   if (got_plt_shndx == elfcpp::SHN_UNDEF)  // Not found.
 186     return false;
 187   if (this->elf_file_.section_link(got_plt_shndx) != inputs_shndx)
 188     return false;
 189
 190   unsigned int strtab_shndx = this->elf_file_.section_link(inputs_shndx);
 191   if (strtab_shndx == elfcpp::SHN_UNDEF
 192       || strtab_shndx > this->elf_file_.shnum()
 193       || this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB)
 194     return false;
 195
 196   if (p_inputs_shndx != NULL)
 197     *p_inputs_shndx = inputs_shndx;
 198   if (p_symtab_shndx != NULL)
 199     *p_symtab_shndx = symtab_shndx;
 200   if (p_relocs_shndx != NULL)
 201     *p_relocs_shndx = relocs_shndx;
 202   if (p_got_plt_shndx != NULL)
 203     *p_got_plt_shndx = got_plt_shndx;
 204   if (p_strtab_shndx != NULL)
 205     *p_strtab_shndx = strtab_shndx;
 206   return true;
 207 }
 208
 209 // Determine whether an incremental link based on the existing output file
 210 // can be done.
 211
 212 template<int size, bool big_endian>
 213 bool
 214 Sized_incremental_binary<size, big_endian>::do_check_inputs(
 215     Incremental_inputs* incremental_inputs)
 216 {
 217   unsigned int inputs_shndx;
 218   unsigned int symtab_shndx;
 219   unsigned int relocs_shndx;
 220   unsigned int plt_got_shndx;
 221   unsigned int strtab_shndx;
 222
 223   if (!do_find_incremental_inputs_sections(&inputs_shndx, &symtab_shndx,
 224                                            &relocs_shndx, &plt_got_shndx,
 225                                            &strtab_shndx))
 226     {
 227       explain_no_incremental(_("no incremental data from previous build"));
 228       return false;
 229     }
 230
 231   Location inputs_location(this->elf_file_.section_contents(inputs_shndx));
 232   Location symtab_location(this->elf_file_.section_contents(symtab_shndx));
 233   Location relocs_location(this->elf_file_.section_contents(relocs_shndx));
 234   Location strtab_location(this->elf_file_.section_contents(strtab_shndx));
 235
 236   View inputs_view(view(inputs_location));
 237   View symtab_view(view(symtab_location));
 238   View relocs_view(view(relocs_location));
 239   View strtab_view(view(strtab_location));
 240
 241   elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size);
 242
 243   Incremental_inputs_reader<size, big_endian>
 244       incoming_inputs(inputs_view.data(), strtab);
 245
 246   if (incoming_inputs.version() != INCREMENTAL_LINK_VERSION)
 247     {
 248       explain_no_incremental(_("different version of incremental build data"));
 249       return false;
 250     }
 251
 252   if (incremental_inputs->command_line() != incoming_inputs.command_line())
 253     {
 254       explain_no_incremental(_("command line changed"));
 255       return false;
 256     }
 257
 258   // TODO: compare incremental_inputs->inputs() with entries in data_view.
 259
 260   return true;
 261 }
 262
 263 namespace
 264 {
 265
 266 // Create a Sized_incremental_binary object of the specified size and
 267 // endianness. Fails if the target architecture is not supported.
 268
 269 template<int size, bool big_endian>
 270 Incremental_binary*
 271 make_sized_incremental_binary(Output_file* file,
 272                               const elfcpp::Ehdr<size, big_endian>& ehdr)
 273 {
 274   Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
 275                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
 276                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
 277   if (target == NULL)
 278     {
 279       explain_no_incremental(_("unsupported ELF machine number %d"),
 280                ehdr.get_e_machine());
 281       return NULL;
 282     }
 283
 284   if (!parameters->target_valid())
 285     set_parameters_target(target);
 286   else if (target != &parameters->target())
 287     gold_error(_("%s: incompatible target"), file->filename());
 288
 289   return new Sized_incremental_binary<size, big_endian>(file, ehdr, target);
 290 }
 291
 292 }  // End of anonymous namespace.
 293
 294 // Create an Incremental_binary object for FILE.  Returns NULL is this is not
 295 // possible, e.g. FILE is not an ELF file or has an unsupported target.  FILE
 296 // should be opened.
 297
 298 Incremental_binary*
 299 open_incremental_binary(Output_file* file)
 300 {
 301   off_t filesize = file->filesize();
 302   int want = elfcpp::Elf_recognizer::max_header_size;
 303   if (filesize < want)
 304     want = filesize;
 305
 306   const unsigned char* p = file->get_input_view(0, want);
 307   if (!elfcpp::Elf_recognizer::is_elf_file(p, want))
 308     {
 309       explain_no_incremental(_("output is not an ELF file."));
 310       return NULL;
 311     }
 312
 313   int size = 0;
 314   bool big_endian = false;
 315   std::string error;
 316   if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian,
 317                                                &error))
 318     {
 319       explain_no_incremental(error.c_str());
 320       return NULL;
 321     }
 322
 323   Incremental_binary* result = NULL;
 324   if (size == 32)
 325     {
 326       if (big_endian)
 327         {
 328 #ifdef HAVE_TARGET_32_BIG
 329           result = make_sized_incremental_binary<32, true>(
 330               file, elfcpp::Ehdr<32, true>(p));
 331 #else
 332           explain_no_incremental(_("unsupported file: 32-bit, big-endian"));
 333 #endif
 334         }
 335       else
 336         {
 337 #ifdef HAVE_TARGET_32_LITTLE
 338           result = make_sized_incremental_binary<32, false>(
 339               file, elfcpp::Ehdr<32, false>(p));
 340 #else
 341           explain_no_incremental(_("unsupported file: 32-bit, little-endian"));
 342 #endif
 343         }
 344     }
 345   else if (size == 64)
 346     {
 347       if (big_endian)
 348         {
 349 #ifdef HAVE_TARGET_64_BIG
 350           result = make_sized_incremental_binary<64, true>(
 351               file, elfcpp::Ehdr<64, true>(p));
 352 #else
 353           explain_no_incremental(_("unsupported file: 64-bit, big-endian"));
 354 #endif
 355         }
 356       else
 357         {
 358 #ifdef HAVE_TARGET_64_LITTLE
 359           result = make_sized_incremental_binary<64, false>(
 360               file, elfcpp::Ehdr<64, false>(p));
 361 #else
 362           explain_no_incremental(_("unsupported file: 64-bit, little-endian"));
 363 #endif
 364         }
 365     }
 366   else
 367     gold_unreachable();
 368
 369   return result;
 370 }
 371
 372 // Analyzes the output file to check if incremental linking is possible and
 373 // (to be done) what files need to be relinked.
 374
 375 bool
 376 Incremental_checker::can_incrementally_link_output_file()
 377 {
 378   Output_file output(this->output_name_);
 379   if (!output.open_for_modification())
 380     return false;
 381   Incremental_binary* binary = open_incremental_binary(&output);
 382   if (binary == NULL)
 383     return false;
 384   return binary->check_inputs(this->incremental_inputs_);
 385 }
 386
 387 // Class Incremental_inputs.
 388
 389 // Add the command line to the string table, setting
 390 // command_line_key_.  In incremental builds, the command line is
 391 // stored in .gnu_incremental_inputs so that the next linker run can
 392 // check if the command line options didn't change.
 393
 394 void
 395 Incremental_inputs::report_command_line(int argc, const char* const* argv)
 396 {
 397   // Always store 'gold' as argv[0] to avoid a full relink if the user used a
 398   // different path to the linker.
 399   std::string args("gold");
 400   // Copied from collect_argv in main.cc.
 401   for (int i = 1; i < argc; ++i)
 402     {
 403       // Adding/removing these options should not result in a full relink.
 404       if (strcmp(argv[i], "--incremental") == 0
 405           || strcmp(argv[i], "--incremental-full") == 0
 406           || strcmp(argv[i], "--incremental-update") == 0
 407           || strcmp(argv[i], "--incremental-changed") == 0
 408           || strcmp(argv[i], "--incremental-unchanged") == 0
 409           || strcmp(argv[i], "--incremental-unknown") == 0)
 410         continue;
 411
 412       args.append(" '");
 413       // Now append argv[i], but with all single-quotes escaped
 414       const char* argpos = argv[i];
 415       while (1)
 416         {
 417           const int len = strcspn(argpos, "'");
 418           args.append(argpos, len);
 419           if (argpos[len] == '\0')
 420             break;
 421           args.append("'\"'\"'");
 422           argpos += len + 1;
 423         }
 424       args.append("'");
 425     }
 426
 427   this->command_line_ = args;
 428   this->strtab_->add(this->command_line_.c_str(), false,
 429                      &this->command_line_key_);
 430 }
 431
 432 // Record the input archive file ARCHIVE.  This is called by the
 433 // Add_archive_symbols task before determining which archive members
 434 // to include.  We create the Incremental_archive_entry here and
 435 // attach it to the Archive, but we do not add it to the list of
 436 // input objects until report_archive_end is called.
 437
 438 void
 439 Incremental_inputs::report_archive_begin(Archive* arch)
 440 {
 441   Stringpool::Key filename_key;
 442   Timespec mtime = arch->file().get_mtime();
 443
 444   this->strtab_->add(arch->filename().c_str(), false, &filename_key);
 445   Incremental_archive_entry* entry =
 446       new Incremental_archive_entry(filename_key, arch, mtime);
 447   arch->set_incremental_info(entry);
 448 }
 449
 450 // Finish recording the input archive file ARCHIVE.  This is called by the
 451 // Add_archive_symbols task after determining which archive members
 452 // to include.
 453
 454 void
 455 Incremental_inputs::report_archive_end(Archive* arch)
 456 {
 457   Incremental_archive_entry* entry = arch->incremental_info();
 458
 459   gold_assert(entry != NULL);
 460
 461   // Collect unused global symbols.
 462   for (Archive::Unused_symbol_iterator p = arch->unused_symbols_begin();
 463        p != arch->unused_symbols_end();
 464        ++p)
 465     {
 466       Stringpool::Key symbol_key;
 467       this->strtab_->add(*p, true, &symbol_key);
 468       entry->add_unused_global_symbol(symbol_key);
 469     }
 470   this->inputs_.push_back(entry);
 471 }
 472
 473 // Record the input object file OBJ.  If ARCH is not NULL, attach
 474 // the object file to the archive.  This is called by the
 475 // Add_symbols task after finding out the type of the file.
 476
 477 void
 478 Incremental_inputs::report_object(Object* obj, Archive* arch)
 479 {
 480   Stringpool::Key filename_key;
 481   Timespec mtime = obj->input_file()->file().get_mtime();
 482
 483   this->strtab_->add(obj->name().c_str(), false, &filename_key);
 484   Incremental_object_entry* obj_entry =
 485       new Incremental_object_entry(filename_key, obj, mtime);
 486   this->inputs_.push_back(obj_entry);
 487
 488   if (arch != NULL)
 489     {
 490       Incremental_archive_entry* arch_entry = arch->incremental_info();
 491       gold_assert(arch_entry != NULL);
 492       arch_entry->add_object(obj_entry);
 493     }
 494
 495   this->current_object_ = obj;
 496   this->current_object_entry_ = obj_entry;
 497 }
 498
 499 // Record the input object file OBJ.  If ARCH is not NULL, attach
 500 // the object file to the archive.  This is called by the
 501 // Add_symbols task after finding out the type of the file.
 502
 503 void
 504 Incremental_inputs::report_input_section(Object* obj, unsigned int shndx,
 505                                          const char* name, off_t sh_size)
 506 {
 507   Stringpool::Key key = 0;
 508
 509   if (name != NULL)
 510       this->strtab_->add(name, true, &key);
 511
 512   gold_assert(obj == this->current_object_);
 513   this->current_object_entry_->add_input_section(shndx, key, sh_size);
 514 }
 515
 516 // Record that the input argument INPUT is a script SCRIPT.  This is
 517 // called by read_script after parsing the script and reading the list
 518 // of inputs added by this script.
 519
 520 void
 521 Incremental_inputs::report_script(const std::string& filename,
 522                                   Script_info* script, Timespec mtime)
 523 {
 524   Stringpool::Key filename_key;
 525
 526   this->strtab_->add(filename.c_str(), false, &filename_key);
 527   Incremental_script_entry* entry =
 528       new Incremental_script_entry(filename_key, script, mtime);
 529   this->inputs_.push_back(entry);
 530 }
 531
 532 // Finalize the incremental link information.  Called from
 533 // Layout::finalize.
 534
 535 void
 536 Incremental_inputs::finalize()
 537 {
 538   // Finalize the string table.
 539   this->strtab_->set_string_offsets();
 540 }
 541
 542 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
 543
 544 void
 545 Incremental_inputs::create_data_sections(Symbol_table* symtab)
 546 {
 547   switch (parameters->size_and_endianness())
 548     {
 549 #ifdef HAVE_TARGET_32_LITTLE
 550     case Parameters::TARGET_32_LITTLE:
 551       this->inputs_section_ =
 552           new Output_section_incremental_inputs<32, false>(this, symtab);
 553       break;
 554 #endif
 555 #ifdef HAVE_TARGET_32_BIG
 556     case Parameters::TARGET_32_BIG:
 557       this->inputs_section_ =
 558           new Output_section_incremental_inputs<32, true>(this, symtab);
 559       break;
 560 #endif
 561 #ifdef HAVE_TARGET_64_LITTLE
 562     case Parameters::TARGET_64_LITTLE:
 563       this->inputs_section_ =
 564           new Output_section_incremental_inputs<64, false>(this, symtab);
 565       break;
 566 #endif
 567 #ifdef HAVE_TARGET_64_BIG
 568     case Parameters::TARGET_64_BIG:
 569       this->inputs_section_ =
 570           new Output_section_incremental_inputs<64, true>(this, symtab);
 571       break;
 572 #endif
 573     default:
 574       gold_unreachable();
 575     }
 576   this->symtab_section_ = new Output_data_space(4, "** incremental_symtab");
 577   this->relocs_section_ = new Output_data_space(4, "** incremental_relocs");
 578   this->got_plt_section_ = new Output_data_space(4, "** incremental_got_plt");
 579 }
 580
 581 // Return the sh_entsize value for the .gnu_incremental_relocs section.
 582 unsigned int
 583 Incremental_inputs::relocs_entsize() const
 584 {
 585   return 8 + 2 * parameters->target().get_size() / 8;
 586 }
 587
 588 // Class Output_section_incremental_inputs.
 589
 590 // Finalize the offsets for each input section and supplemental info block,
 591 // and set the final data size of the incremental output sections.
 592
 593 template<int size, bool big_endian>
 594 void
 595 Output_section_incremental_inputs<size, big_endian>::set_final_data_size()
 596 {
 597   const Incremental_inputs* inputs = this->inputs_;
 598   const unsigned int sizeof_addr = size / 8;
 599   const unsigned int rel_size = 8 + 2 * sizeof_addr;
 600
 601   // Offset of each input entry.
 602   unsigned int input_offset = this->header_size;
 603
 604   // Offset of each supplemental info block.
 605   unsigned int info_offset = this->header_size;
 606   info_offset += this->input_entry_size * inputs->input_file_count();
 607
 608   // Count each input file and its supplemental information block.
 609   for (Incremental_inputs::Input_list::const_iterator p =
 610            inputs->input_files().begin();
 611        p != inputs->input_files().end();
 612        ++p)
 613     {
 614       // Set the offset of the input file entry.
 615       (*p)->set_offset(input_offset);
 616       input_offset += this->input_entry_size;
 617
 618       // Set the offset of the supplemental info block.
 619       switch ((*p)->type())
 620         {
 621         case INCREMENTAL_INPUT_SCRIPT:
 622           // No supplemental info for a script.
 623           (*p)->set_info_offset(0);
 624           break;
 625         case INCREMENTAL_INPUT_OBJECT:
 626         case INCREMENTAL_INPUT_ARCHIVE_MEMBER:
 627           {
 628             Incremental_object_entry* entry = (*p)->object_entry();
 629             gold_assert(entry != NULL);
 630             (*p)->set_info_offset(info_offset);
 631             // Input section count + global symbol count.
 632             info_offset += 8;
 633             // Each input section.
 634             info_offset += (entry->get_input_section_count()
 635                             * (8 + 2 * sizeof_addr));
 636             // Each global symbol.
 637             const Object::Symbols* syms = entry->object()->get_global_symbols();
 638             info_offset += syms->size() * 16;
 639           }
 640           break;
 641         case INCREMENTAL_INPUT_SHARED_LIBRARY:
 642           {
 643             Incremental_object_entry* entry = (*p)->object_entry();
 644             gold_assert(entry != NULL);
 645             (*p)->set_info_offset(info_offset);
 646             // Global symbol count.
 647             info_offset += 4;
 648             // Each global symbol.
 649             const Object::Symbols* syms = entry->object()->get_global_symbols();
 650             unsigned int nsyms = syms != NULL ? syms->size() : 0;
 651             info_offset += nsyms * 4;
 652           }
 653           break;
 654         case INCREMENTAL_INPUT_ARCHIVE:
 655           {
 656             Incremental_archive_entry* entry = (*p)->archive_entry();
 657             gold_assert(entry != NULL);
 658             (*p)->set_info_offset(info_offset);
 659             // Member count + unused global symbol count.
 660             info_offset += 8;
 661             // Each member.
 662             info_offset += (entry->get_member_count() * 4);
 663             // Each global symbol.
 664             info_offset += (entry->get_unused_global_symbol_count() * 4);
 665           }
 666           break;
 667         default:
 668           gold_unreachable();
 669         }
 670     }
 671
 672   this->set_data_size(info_offset);
 673
 674   // Set the size of the .gnu_incremental_symtab section.
 675   inputs->symtab_section()->set_current_data_size(this->symtab_->output_count()
 676                                                   * sizeof(unsigned int));
 677
 678   // Set the size of the .gnu_incremental_relocs section.
 679   inputs->relocs_section()->set_current_data_size(inputs->get_reloc_count()
 680                                                   * rel_size);
 681
 682   // Set the size of the .gnu_incremental_got_plt section.
 683   Sized_target<size, big_endian>* target =
 684     parameters->sized_target<size, big_endian>();
 685   unsigned int got_count = target->got_entry_count();
 686   unsigned int plt_count = target->plt_entry_count();
 687   unsigned int got_plt_size = 8;  // GOT entry count, PLT entry count.
 688   got_plt_size = (got_plt_size + got_count + 3) & ~3;  // GOT type array.
 689   got_plt_size += got_count * 4 + plt_count * 4;  // GOT array, PLT array.
 690   inputs->got_plt_section()->set_current_data_size(got_plt_size);
 691 }
 692
 693 // Write the contents of the .gnu_incremental_inputs and
 694 // .gnu_incremental_symtab sections.
 695
 696 template<int size, bool big_endian>
 697 void
 698 Output_section_incremental_inputs<size, big_endian>::do_write(Output_file* of)
 699 {
 700   const Incremental_inputs* inputs = this->inputs_;
 701   Stringpool* strtab = inputs->get_stringpool();
 702
 703   // Get a view into the .gnu_incremental_inputs section.
 704   const off_t off = this->offset();
 705   const off_t oview_size = this->data_size();
 706   unsigned char* const oview = of->get_output_view(off, oview_size);
 707   unsigned char* pov = oview;
 708
 709   // Get a view into the .gnu_incremental_symtab section.
 710   const off_t symtab_off = inputs->symtab_section()->offset();
 711   const off_t symtab_size = inputs->symtab_section()->data_size();
 712   unsigned char* const symtab_view = of->get_output_view(symtab_off,
 713                                                          symtab_size);
 714
 715   // Allocate an array of linked list heads for the .gnu_incremental_symtab
 716   // section.  Each element corresponds to a global symbol in the output
 717   // symbol table, and points to the head of the linked list that threads
 718   // through the object file input entries.  The value of each element
 719   // is the section-relative offset to a global symbol entry in a
 720   // supplemental information block.
 721   unsigned int global_sym_count = this->symtab_->output_count();
 722   unsigned int* global_syms = new unsigned int[global_sym_count];
 723   memset(global_syms, 0, global_sym_count * sizeof(unsigned int));
 724
 725   // Write the section header.
 726   Stringpool::Key command_line_key = inputs->command_line_key();
 727   pov = this->write_header(pov, inputs->input_file_count(),
 728                            strtab->get_offset_from_key(command_line_key));
 729
 730   // Write the list of input files.
 731   pov = this->write_input_files(oview, pov, strtab);
 732
 733   // Write the supplemental information blocks for each input file.
 734   pov = this->write_info_blocks(oview, pov, strtab, global_syms,
 735                                 global_sym_count);
 736
 737   gold_assert(pov - oview == oview_size);
 738
 739   // Write the .gnu_incremental_symtab section.
 740   gold_assert(global_sym_count * 4 == symtab_size);
 741   this->write_symtab(symtab_view, global_syms, global_sym_count);
 742
 743   delete[] global_syms;
 744
 745   // Write the .gnu_incremental_got_plt section.
 746   const off_t got_plt_off = inputs->got_plt_section()->offset();
 747   const off_t got_plt_size = inputs->got_plt_section()->data_size();
 748   unsigned char* const got_plt_view = of->get_output_view(got_plt_off,
 749                                                           got_plt_size);
 750   this->write_got_plt(got_plt_view, got_plt_size);
 751
 752   of->write_output_view(off, oview_size, oview);
 753   of->write_output_view(symtab_off, symtab_size, symtab_view);
 754   of->write_output_view(got_plt_off, got_plt_size, got_plt_view);
 755 }
 756
 757 // Write the section header: version, input file count, offset of command line
 758 // in the string table, and 4 bytes of padding.
 759
 760 template<int size, bool big_endian>
 761 unsigned char*
 762 Output_section_incremental_inputs<size, big_endian>::write_header(
 763     unsigned char* pov,
 764     unsigned int input_file_count,
 765     section_offset_type command_line_offset)
 766 {
 767   Swap32::writeval(pov, INCREMENTAL_LINK_VERSION);
 768   Swap32::writeval(pov + 4, input_file_count);
 769   Swap32::writeval(pov + 8, command_line_offset);
 770   Swap32::writeval(pov + 12, 0);
 771   return pov + this->header_size;
 772 }
 773
 774 // Write the input file entries.
 775
 776 template<int size, bool big_endian>
 777 unsigned char*
 778 Output_section_incremental_inputs<size, big_endian>::write_input_files(
 779     unsigned char* oview,
 780     unsigned char* pov,
 781     Stringpool* strtab)
 782 {
 783   const Incremental_inputs* inputs = this->inputs_;
 784
 785   for (Incremental_inputs::Input_list::const_iterator p =
 786            inputs->input_files().begin();
 787        p != inputs->input_files().end();
 788        ++p)
 789     {
 790       gold_assert(static_cast<unsigned int>(pov - oview) == (*p)->get_offset());
 791       section_offset_type filename_offset =
 792           strtab->get_offset_from_key((*p)->get_filename_key());
 793       const Timespec& mtime = (*p)->get_mtime();
 794       Swap32::writeval(pov, filename_offset);
 795       Swap32::writeval(pov + 4, (*p)->get_info_offset());
 796       Swap64::writeval(pov + 8, mtime.seconds);
 797       Swap32::writeval(pov + 16, mtime.nanoseconds);
 798       Swap16::writeval(pov + 20, (*p)->type());
 799       Swap16::writeval(pov + 22, 0);
 800       pov += this->input_entry_size;
 801     }
 802   return pov;
 803 }
 804
 805 // Write the supplemental information blocks.
 806
 807 template<int size, bool big_endian>
 808 unsigned char*
 809 Output_section_incremental_inputs<size, big_endian>::write_info_blocks(
 810     unsigned char* oview,
 811     unsigned char* pov,
 812     Stringpool* strtab,
 813     unsigned int* global_syms,
 814     unsigned int global_sym_count)
 815 {
 816   const Incremental_inputs* inputs = this->inputs_;
 817   unsigned int first_global_index = this->symtab_->first_global_index();
 818
 819   for (Incremental_inputs::Input_list::const_iterator p =
 820            inputs->input_files().begin();
 821        p != inputs->input_files().end();
 822        ++p)
 823     {
 824       switch ((*p)->type())
 825         {
 826         case INCREMENTAL_INPUT_SCRIPT:
 827           // No supplemental info for a script.
 828           break;
 829
 830         case INCREMENTAL_INPUT_OBJECT:
 831         case INCREMENTAL_INPUT_ARCHIVE_MEMBER:
 832           {
 833             gold_assert(static_cast<unsigned int>(pov - oview)
 834                         == (*p)->get_info_offset());
 835             Incremental_object_entry* entry = (*p)->object_entry();
 836             gold_assert(entry != NULL);
 837             const Object* obj = entry->object();
 838             const Object::Symbols* syms = obj->get_global_symbols();
 839             // Write the input section count and global symbol count.
 840             unsigned int nsections = entry->get_input_section_count();
 841             unsigned int nsyms = syms->size();
 842             Swap32::writeval(pov, nsections);
 843             Swap32::writeval(pov + 4, nsyms);
 844             pov += 8;
 845
 846             // For each input section, write the name, output section index,
 847             // offset within output section, and input section size.
 848             for (unsigned int i = 0; i < nsections; i++)
 849               {
 850                 Stringpool::Key key = entry->get_input_section_name_key(i);
 851                 off_t name_offset = 0;
 852                 if (key != 0)
 853                   name_offset = strtab->get_offset_from_key(key);
 854                 int out_shndx = 0;
 855                 off_t out_offset = 0;
 856                 off_t sh_size = 0;
 857                 Output_section* os = obj->output_section(i);
 858                 if (os != NULL)
 859                   {
 860                     out_shndx = os->out_shndx();
 861                     out_offset = obj->output_section_offset(i);
 862                     sh_size = entry->get_input_section_size(i);
 863                   }
 864                 Swap32::writeval(pov, name_offset);
 865                 Swap32::writeval(pov + 4, out_shndx);
 866                 Swap::writeval(pov + 8, out_offset);
 867                 Swap::writeval(pov + 8 + sizeof_addr, sh_size);
 868                 pov += 8 + 2 * sizeof_addr;
 869               }
 870
 871             // For each global symbol, write its associated relocations,
 872             // add it to the linked list of globals, then write the
 873             // supplemental information:  global symbol table index,
 874             // linked list chain pointer, relocation count, and offset
 875             // to the relocations.
 876             for (unsigned int i = 0; i < nsyms; i++)
 877               {
 878                 const Symbol* sym = (*syms)[i];
 879                 if (sym->is_forwarder())
 880                   sym = this->symtab_->resolve_forwards(sym);
 881                 unsigned int symtab_index = sym->symtab_index();
 882                 unsigned int chain = 0;
 883                 unsigned int first_reloc = 0;
 884                 unsigned int nrelocs = obj->get_incremental_reloc_count(i);
 885                 if (nrelocs > 0)
 886                   {
 887                     gold_assert(symtab_index != -1U
 888                                 && (symtab_index - first_global_index
 889                                     < global_sym_count));
 890                     first_reloc = obj->get_incremental_reloc_base(i);
 891                     chain = global_syms[symtab_index - first_global_index];
 892                     global_syms[symtab_index - first_global_index] =
 893                         pov - oview;
 894                   }
 895                 Swap32::writeval(pov, symtab_index);
 896                 Swap32::writeval(pov + 4, chain);
 897                 Swap32::writeval(pov + 8, nrelocs);
 898                 Swap32::writeval(pov + 12, first_reloc * 3 * sizeof_addr);
 899                 pov += 16;
 900               }
 901           }
 902           break;
 903
 904         case INCREMENTAL_INPUT_SHARED_LIBRARY:
 905           {
 906             gold_assert(static_cast<unsigned int>(pov - oview)
 907                         == (*p)->get_info_offset());
 908             Incremental_object_entry* entry = (*p)->object_entry();
 909             gold_assert(entry != NULL);
 910             const Object* obj = entry->object();
 911             const Object::Symbols* syms = obj->get_global_symbols();
 912
 913             // Write the global symbol count.
 914             unsigned int nsyms = syms != NULL ? syms->size() : 0;
 915             Swap32::writeval(pov, nsyms);
 916             pov += 4;
 917
 918             // For each global symbol, write the global symbol table index.
 919             for (unsigned int i = 0; i < nsyms; i++)
 920               {
 921                 const Symbol* sym = (*syms)[i];
 922                 Swap32::writeval(pov, sym->symtab_index());
 923                 pov += 4;
 924               }
 925           }
 926           break;
 927
 928         case INCREMENTAL_INPUT_ARCHIVE:
 929           {
 930             gold_assert(static_cast<unsigned int>(pov - oview)
 931                         == (*p)->get_info_offset());
 932             Incremental_archive_entry* entry = (*p)->archive_entry();
 933             gold_assert(entry != NULL);
 934
 935             // Write the member count and unused global symbol count.
 936             unsigned int nmembers = entry->get_member_count();
 937             unsigned int nsyms = entry->get_unused_global_symbol_count();
 938             Swap32::writeval(pov, nmembers);
 939             Swap32::writeval(pov + 4, nsyms);
 940             pov += 8;
 941
 942             // For each member, write the offset to its input file entry.
 943             for (unsigned int i = 0; i < nmembers; ++i)
 944               {
 945                 Incremental_object_entry* member = entry->get_member(i);
 946                 Swap32::writeval(pov, member->get_offset());
 947                 pov += 4;
 948               }
 949
 950             // For each global symbol, write the name offset.
 951             for (unsigned int i = 0; i < nsyms; ++i)
 952               {
 953                 Stringpool::Key key = entry->get_unused_global_symbol(i);
 954                 Swap32::writeval(pov, strtab->get_offset_from_key(key));
 955                 pov += 4;
 956               }
 957           }
 958           break;
 959
 960         default:
 961           gold_unreachable();
 962         }
 963     }
 964   return pov;
 965 }
 966
 967 // Write the contents of the .gnu_incremental_symtab section.
 968
 969 template<int size, bool big_endian>
 970 void
 971 Output_section_incremental_inputs<size, big_endian>::write_symtab(
 972     unsigned char* pov,
 973     unsigned int* global_syms,
 974     unsigned int global_sym_count)
 975 {
 976   for (unsigned int i = 0; i < global_sym_count; ++i)
 977     {
 978       Swap32::writeval(pov, global_syms[i]);
 979       pov += 4;
 980     }
 981 }
 982
 983 // This struct holds the view information needed to write the
 984 // .gnu_incremental_got_plt section.
 985
 986 struct Got_plt_view_info
 987 {
 988   // Start of the GOT type array in the output view.
 989   unsigned char* got_type_p;
 990   // Start of the GOT descriptor array in the output view.
 991   unsigned char* got_desc_p;
 992   // Start of the PLT descriptor array in the output view.
 993   unsigned char* plt_desc_p;
 994   // Number of GOT entries.
 995   unsigned int got_count;
 996   // Number of PLT entries.
 997   unsigned int plt_count;
 998   // Offset of the first non-reserved PLT entry (this is a target-dependent value).
 999   unsigned int first_plt_entry_offset;
1000   // Size of a PLT entry (this is a target-dependent value).
1001   unsigned int plt_entry_size;
1002   // Value to write in the GOT descriptor array.  For global symbols,
1003   // this is the global symbol table index; for local symbols, it is
1004   // the offset of the input file entry in the .gnu_incremental_inputs
1005   // section.
1006   unsigned int got_descriptor;
1007 };
1008
1009 // Functor class for processing a GOT offset list for local symbols.
1010 // Writes the GOT type and symbol index into the GOT type and descriptor
1011 // arrays in the output section.
1012
1013 template<int size, bool big_endian>
1014 class Local_got_offset_visitor
1015 {
1016  public:
1017   Local_got_offset_visitor(struct Got_plt_view_info& info)
1018     : info_(info)
1019   { }
1020
1021   void
1022   operator()(unsigned int got_type, unsigned int got_offset)
1023   {
1024     unsigned int got_index = got_offset / this->got_entry_size_;
1025     gold_assert(got_index < this->info_.got_count);
1026     // We can only handle GOT entry types in the range 0..0x7e
1027     // because we use a byte array to store them, and we use the
1028     // high bit to flag a local symbol.
1029     gold_assert(got_type < 0x7f);
1030     this->info_.got_type_p[got_index] = got_type | 0x80;
1031     unsigned char* pov = this->info_.got_desc_p + got_index * 4;
1032     elfcpp::Swap<32, big_endian>::writeval(pov, this->info_.got_descriptor);
1033   }
1034
1035  private:
1036   static const unsigned int got_entry_size_ = size / 8;
1037   struct Got_plt_view_info& info_;
1038 };
1039
1040 // Functor class for processing a GOT offset list.  Writes the GOT type
1041 // and symbol index into the GOT type and descriptor arrays in the output
1042 // section.
1043
1044 template<int size, bool big_endian>
1045 class Global_got_offset_visitor
1046 {
1047  public:
1048   Global_got_offset_visitor(struct Got_plt_view_info& info)
1049     : info_(info)
1050   { }
1051
1052   void
1053   operator()(unsigned int got_type, unsigned int got_offset)
1054   {
1055     unsigned int got_index = got_offset / this->got_entry_size_;
1056     gold_assert(got_index < this->info_.got_count);
1057     // We can only handle GOT entry types in the range 0..0x7e
1058     // because we use a byte array to store them, and we use the
1059     // high bit to flag a local symbol.
1060     gold_assert(got_type < 0x7f);
1061     this->info_.got_type_p[got_index] = got_type;
1062     unsigned char* pov = this->info_.got_desc_p + got_index * 4;
1063     elfcpp::Swap<32, big_endian>::writeval(pov, this->info_.got_descriptor);
1064   }
1065
1066  private:
1067   static const unsigned int got_entry_size_ = size / 8;
1068   struct Got_plt_view_info& info_;
1069 };
1070
1071 // Functor class for processing the global symbol table.  Processes the
1072 // GOT offset list for the symbol, and writes the symbol table index
1073 // into the PLT descriptor array in the output section.
1074
1075 template<int size, bool big_endian>
1076 class Global_symbol_visitor_got_plt
1077 {
1078  public:
1079   Global_symbol_visitor_got_plt(struct Got_plt_view_info& info)
1080     : info_(info)
1081   { }
1082
1083   void
1084   operator()(const Sized_symbol<size>* sym)
1085   {
1086     typedef Global_got_offset_visitor<size, big_endian> Got_visitor;
1087     const Got_offset_list* got_offsets = sym->got_offset_list();
1088     if (got_offsets != NULL)
1089       {
1090         info_.got_descriptor = sym->symtab_index();
1091         got_offsets->for_all_got_offsets(Got_visitor(info_));
1092       }
1093     if (sym->has_plt_offset())
1094       {
1095         unsigned int plt_index =
1096             ((sym->plt_offset() - this->info_.first_plt_entry_offset)
1097              / this->info_.plt_entry_size);
1098         gold_assert(plt_index < this->info_.plt_count);
1099         unsigned char* pov = this->info_.plt_desc_p + plt_index * 4;
1100         elfcpp::Swap<32, big_endian>::writeval(pov, sym->symtab_index());
1101       }
1102   }
1103
1104  private:
1105   struct Got_plt_view_info& info_;
1106 };
1107
1108 // Write the contents of the .gnu_incremental_got_plt section.
1109
1110 template<int size, bool big_endian>
1111 void
1112 Output_section_incremental_inputs<size, big_endian>::write_got_plt(
1113     unsigned char* pov,
1114     off_t view_size)
1115 {
1116   Sized_target<size, big_endian>* target =
1117     parameters->sized_target<size, big_endian>();
1118
1119   // Set up the view information for the functors.
1120   struct Got_plt_view_info view_info;
1121   view_info.got_count = target->got_entry_count();
1122   view_info.plt_count = target->plt_entry_count();
1123   view_info.first_plt_entry_offset = target->first_plt_entry_offset();
1124   view_info.plt_entry_size = target->plt_entry_size();
1125   view_info.got_type_p = pov + 8;
1126   view_info.got_desc_p = (view_info.got_type_p
1127                           + ((view_info.got_count + 3) & ~3));
1128   view_info.plt_desc_p = view_info.got_desc_p + view_info.got_count * 4;
1129
1130   gold_assert(pov + view_size ==
1131               view_info.plt_desc_p + view_info.plt_count * 4);
1132
1133   // Write the section header.
1134   Swap32::writeval(pov, view_info.got_count);
1135   Swap32::writeval(pov + 4, view_info.plt_count);
1136
1137   // Initialize the GOT type array to 0xff (reserved).
1138   memset(view_info.got_type_p, 0xff, view_info.got_count);
1139
1140   // Write the incremental GOT descriptors for local symbols.
1141   for (Incremental_inputs::Input_list::const_iterator p =
1142            this->inputs_->input_files().begin();
1143        p != this->inputs_->input_files().end();
1144        ++p)
1145     {
1146       if ((*p)->type() != INCREMENTAL_INPUT_OBJECT
1147           && (*p)->type() != INCREMENTAL_INPUT_ARCHIVE_MEMBER)
1148         continue;
1149       Incremental_object_entry* entry = (*p)->object_entry();
1150       gold_assert(entry != NULL);
1151       const Sized_relobj<size, big_endian>* obj =
1152           static_cast<Sized_relobj<size, big_endian>*>(entry->object());
1153       gold_assert(obj != NULL);
1154       unsigned int nsyms = obj->local_symbol_count();
1155       for (unsigned int i = 0; i < nsyms; i++)
1156         {
1157           const Got_offset_list* got_offsets = obj->local_got_offset_list(i);
1158           if (got_offsets != NULL)
1159             {
1160               typedef Local_got_offset_visitor<size, big_endian> Got_visitor;
1161               view_info.got_descriptor = (*p)->get_offset();
1162               got_offsets->for_all_got_offsets(Got_visitor(view_info));
1163             }
1164         }
1165     }
1166
1167   // Write the incremental GOT and PLT descriptors for global symbols.
1168   typedef Global_symbol_visitor_got_plt<size, big_endian> Symbol_visitor;
1169   symtab_->for_all_symbols<size, Symbol_visitor>(Symbol_visitor(view_info));
1170 }
1171
1172 // Instantiate the templates we need.
1173
1174 #ifdef HAVE_TARGET_32_LITTLE
1175 template
1176 class Sized_incremental_binary<32, false>;
1177 #endif
1178
1179 #ifdef HAVE_TARGET_32_BIG
1180 template
1181 class Sized_incremental_binary<32, true>;
1182 #endif
1183
1184 #ifdef HAVE_TARGET_64_LITTLE
1185 template
1186 class Sized_incremental_binary<64, false>;
1187 #endif
1188
1189 #ifdef HAVE_TARGET_64_BIG
1190 template
1191 class Sized_incremental_binary<64, true>;
1192 #endif
1193
1194 } // End namespace gold.