gold/reloc.cc

   1 // reloc.cc -- relocate input files for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@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 <algorithm>
  26
  27 #include "workqueue.h"
  28 #include "symtab.h"
  29 #include "output.h"
  30 #include "merge.h"
  31 #include "object.h"
  32 #include "target-reloc.h"
  33 #include "reloc.h"
  34 #include "icf.h"
  35
  36 namespace gold
  37 {
  38
  39 // Read_relocs methods.
  40
  41 // These tasks just read the relocation information from the file.
  42 // After reading it, the start another task to process the
  43 // information.  These tasks requires access to the file.
  44
  45 Task_token*
  46 Read_relocs::is_runnable()
  47 {
  48   return this->object_->is_locked() ? this->object_->token() : NULL;
  49 }
  50
  51 // Lock the file.
  52
  53 void
  54 Read_relocs::locks(Task_locker* tl)
  55 {
  56   tl->add(this, this->object_->token());
  57 }
  58
  59 // Read the relocations and then start a Scan_relocs_task.
  60
  61 void
  62 Read_relocs::run(Workqueue* workqueue)
  63 {
  64   Read_relocs_data *rd = new Read_relocs_data;
  65   this->object_->read_relocs(rd);
  66   this->object_->set_relocs_data(rd);
  67   this->object_->release();
  68
  69   // If garbage collection or identical comdat folding is desired, we
  70   // process the relocs first before scanning them.  Scanning of relocs is
  71   // done only after garbage or identical sections is identified.
  72   if (parameters->options().gc_sections()
  73       || parameters->options().icf_enabled())
  74     {
  75       workqueue->queue_next(new Gc_process_relocs(this->symtab_,
  76                                                   this->layout_,
  77                                                   this->object_, rd,
  78                                                   this->this_blocker_,
  79                                                   this->next_blocker_));
  80     }
  81   else
  82     {
  83       workqueue->queue_next(new Scan_relocs(this->symtab_, this->layout_,
  84                                             this->object_, rd,
  85                                             this->this_blocker_,
  86                                             this->next_blocker_));
  87     }
  88 }
  89
  90 // Return a debugging name for the task.
  91
  92 std::string
  93 Read_relocs::get_name() const
  94 {
  95   return "Read_relocs " + this->object_->name();
  96 }
  97
  98 // Gc_process_relocs methods.
  99
 100 Gc_process_relocs::~Gc_process_relocs()
 101 {
 102   if (this->this_blocker_ != NULL)
 103     delete this->this_blocker_;
 104 }
 105
 106 // These tasks process the relocations read by Read_relocs and
 107 // determine which sections are referenced and which are garbage.
 108 // This task is done only when --gc-sections is used.  This is blocked
 109 // by THIS_BLOCKER_.  It unblocks NEXT_BLOCKER_.
 110
 111 Task_token*
 112 Gc_process_relocs::is_runnable()
 113 {
 114   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 115     return this->this_blocker_;
 116   if (this->object_->is_locked())
 117     return this->object_->token();
 118   return NULL;
 119 }
 120
 121 void
 122 Gc_process_relocs::locks(Task_locker* tl)
 123 {
 124   tl->add(this, this->object_->token());
 125   tl->add(this, this->next_blocker_);
 126 }
 127
 128 void
 129 Gc_process_relocs::run(Workqueue*)
 130 {
 131   this->object_->gc_process_relocs(this->symtab_, this->layout_, this->rd_);
 132   this->object_->release();
 133 }
 134
 135 // Return a debugging name for the task.
 136
 137 std::string
 138 Gc_process_relocs::get_name() const
 139 {
 140   return "Gc_process_relocs " + this->object_->name();
 141 }
 142
 143 // Scan_relocs methods.
 144
 145 Scan_relocs::~Scan_relocs()
 146 {
 147   if (this->this_blocker_ != NULL)
 148     delete this->this_blocker_;
 149 }
 150
 151 // These tasks scan the relocations read by Read_relocs and mark up
 152 // the symbol table to indicate which relocations are required.  We
 153 // use a lock on the symbol table to keep them from interfering with
 154 // each other.
 155
 156 Task_token*
 157 Scan_relocs::is_runnable()
 158 {
 159   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 160     return this->this_blocker_;
 161   if (this->object_->is_locked())
 162     return this->object_->token();
 163   return NULL;
 164 }
 165
 166 // Return the locks we hold: one on the file, one on the symbol table
 167 // and one blocker.
 168
 169 void
 170 Scan_relocs::locks(Task_locker* tl)
 171 {
 172   tl->add(this, this->object_->token());
 173   tl->add(this, this->next_blocker_);
 174 }
 175
 176 // Scan the relocs.
 177
 178 void
 179 Scan_relocs::run(Workqueue*)
 180 {
 181   this->object_->scan_relocs(this->symtab_, this->layout_, this->rd_);
 182   delete this->rd_;
 183   this->rd_ = NULL;
 184   this->object_->release();
 185 }
 186
 187 // Return a debugging name for the task.
 188
 189 std::string
 190 Scan_relocs::get_name() const
 191 {
 192   return "Scan_relocs " + this->object_->name();
 193 }
 194
 195 // Relocate_task methods.
 196
 197 // We may have to wait for the output sections to be written.
 198
 199 Task_token*
 200 Relocate_task::is_runnable()
 201 {
 202   if (this->object_->relocs_must_follow_section_writes()
 203       && this->output_sections_blocker_->is_blocked())
 204     return this->output_sections_blocker_;
 205
 206   if (this->object_->is_locked())
 207     return this->object_->token();
 208
 209   return NULL;
 210 }
 211
 212 // We want to lock the file while we run.  We want to unblock
 213 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
 214 // INPUT_SECTIONS_BLOCKER may be NULL.
 215
 216 void
 217 Relocate_task::locks(Task_locker* tl)
 218 {
 219   if (this->input_sections_blocker_ != NULL)
 220     tl->add(this, this->input_sections_blocker_);
 221   tl->add(this, this->final_blocker_);
 222   tl->add(this, this->object_->token());
 223 }
 224
 225 // Run the task.
 226
 227 void
 228 Relocate_task::run(Workqueue*)
 229 {
 230   this->object_->relocate(this->symtab_, this->layout_, this->of_);
 231
 232   // This is normally the last thing we will do with an object, so
 233   // uncache all views.
 234   this->object_->clear_view_cache_marks();
 235
 236   this->object_->release();
 237 }
 238
 239 // Return a debugging name for the task.
 240
 241 std::string
 242 Relocate_task::get_name() const
 243 {
 244   return "Relocate_task " + this->object_->name();
 245 }
 246
 247 // Read the relocs and local symbols from the object file and store
 248 // the information in RD.
 249
 250 template<int size, bool big_endian>
 251 void
 252 Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
 253 {
 254   rd->relocs.clear();
 255
 256   unsigned int shnum = this->shnum();
 257   if (shnum == 0)
 258     return;
 259
 260   rd->relocs.reserve(shnum / 2);
 261
 262   const Output_sections& out_sections(this->output_sections());
 263   const std::vector<Address>& out_offsets(this->section_offsets_);
 264
 265   const unsigned char *pshdrs = this->get_view(this->elf_file_.shoff(),
 266                                                shnum * This::shdr_size,
 267                                                true, true);
 268   // Skip the first, dummy, section.
 269   const unsigned char *ps = pshdrs + This::shdr_size;
 270   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
 271     {
 272       typename This::Shdr shdr(ps);
 273
 274       unsigned int sh_type = shdr.get_sh_type();
 275       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 276         continue;
 277
 278       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
 279       if (shndx >= shnum)
 280         {
 281           this->error(_("relocation section %u has bad info %u"),
 282                       i, shndx);
 283           continue;
 284         }
 285
 286       Output_section* os = out_sections[shndx];
 287       if (os == NULL)
 288         continue;
 289
 290       // We are scanning relocations in order to fill out the GOT and
 291       // PLT sections.  Relocations for sections which are not
 292       // allocated (typically debugging sections) should not add new
 293       // GOT and PLT entries.  So we skip them unless this is a
 294       // relocatable link or we need to emit relocations.  FIXME: What
 295       // should we do if a linker script maps a section with SHF_ALLOC
 296       // clear to a section with SHF_ALLOC set?
 297       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
 298       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
 299                                    != 0);
 300       if (!is_section_allocated
 301           && !parameters->options().relocatable()
 302           && !parameters->options().emit_relocs())
 303         continue;
 304
 305       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 306         {
 307           this->error(_("relocation section %u uses unexpected "
 308                         "symbol table %u"),
 309                       i, this->adjust_shndx(shdr.get_sh_link()));
 310           continue;
 311         }
 312
 313       off_t sh_size = shdr.get_sh_size();
 314
 315       unsigned int reloc_size;
 316       if (sh_type == elfcpp::SHT_REL)
 317         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 318       else
 319         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 320       if (reloc_size != shdr.get_sh_entsize())
 321         {
 322           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
 323                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 324                       reloc_size);
 325           continue;
 326         }
 327
 328       size_t reloc_count = sh_size / reloc_size;
 329       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 330         {
 331           this->error(_("reloc section %u size %lu uneven"),
 332                       i, static_cast<unsigned long>(sh_size));
 333           continue;
 334         }
 335
 336       rd->relocs.push_back(Section_relocs());
 337       Section_relocs& sr(rd->relocs.back());
 338       sr.reloc_shndx = i;
 339       sr.data_shndx = shndx;
 340       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
 341                                            true, true);
 342       sr.sh_type = sh_type;
 343       sr.reloc_count = reloc_count;
 344       sr.output_section = os;
 345       sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
 346       sr.is_data_section_allocated = is_section_allocated;
 347     }
 348
 349   // Read the local symbols.
 350   gold_assert(this->symtab_shndx_ != -1U);
 351   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
 352     rd->local_symbols = NULL;
 353   else
 354     {
 355       typename This::Shdr symtabshdr(pshdrs
 356                                      + this->symtab_shndx_ * This::shdr_size);
 357       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
 358       const int sym_size = This::sym_size;
 359       const unsigned int loccount = this->local_symbol_count_;
 360       gold_assert(loccount == symtabshdr.get_sh_info());
 361       off_t locsize = loccount * sym_size;
 362       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
 363                                                  locsize, true, true);
 364     }
 365 }
 366
 367 // Process the relocs to generate mappings from source sections to referenced
 368 // sections.  This is used during garbage colletion to determine garbage
 369 // sections.
 370
 371 template<int size, bool big_endian>
 372 void
 373 Sized_relobj<size, big_endian>::do_gc_process_relocs(Symbol_table* symtab,
 374                                                      Layout* layout,
 375                                                      Read_relocs_data* rd)
 376 {
 377   Sized_target<size, big_endian>* target =
 378     parameters->sized_target<size, big_endian>();
 379
 380   const unsigned char* local_symbols;
 381   if (rd->local_symbols == NULL)
 382     local_symbols = NULL;
 383   else
 384     local_symbols = rd->local_symbols->data();
 385
 386   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 387        p != rd->relocs.end();
 388        ++p)
 389     {
 390       if (!parameters->options().relocatable())
 391           {
 392             // As noted above, when not generating an object file, we
 393             // only scan allocated sections.  We may see a non-allocated
 394             // section here if we are emitting relocs.
 395             if (p->is_data_section_allocated)
 396               target->gc_process_relocs(symtab, layout, this,
 397                                         p->data_shndx, p->sh_type,
 398                                         p->contents->data(), p->reloc_count,
 399                                         p->output_section,
 400                                         p->needs_special_offset_handling,
 401                                         this->local_symbol_count_,
 402                                         local_symbols);
 403         }
 404     }
 405 }
 406
 407
 408 // Scan the relocs and adjust the symbol table.  This looks for
 409 // relocations which require GOT/PLT/COPY relocations.
 410
 411 template<int size, bool big_endian>
 412 void
 413 Sized_relobj<size, big_endian>::do_scan_relocs(Symbol_table* symtab,
 414                                                Layout* layout,
 415                                                Read_relocs_data* rd)
 416 {
 417   Sized_target<size, big_endian>* target =
 418     parameters->sized_target<size, big_endian>();
 419
 420   const unsigned char* local_symbols;
 421   if (rd->local_symbols == NULL)
 422     local_symbols = NULL;
 423   else
 424     local_symbols = rd->local_symbols->data();
 425
 426   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 427        p != rd->relocs.end();
 428        ++p)
 429     {
 430       // When garbage collection is on, unreferenced sections are not included
 431       // in the link that would have been included normally. This is known only
 432       // after Read_relocs hence this check has to be done again.
 433       if (parameters->options().gc_sections()
 434           || parameters->options().icf_enabled())
 435         {
 436           if (p->output_section == NULL)
 437             continue;
 438         }
 439       if (!parameters->options().relocatable())
 440         {
 441           // As noted above, when not generating an object file, we
 442           // only scan allocated sections.  We may see a non-allocated
 443           // section here if we are emitting relocs.
 444           if (p->is_data_section_allocated)
 445             target->scan_relocs(symtab, layout, this, p->data_shndx,
 446                                 p->sh_type, p->contents->data(),
 447                                 p->reloc_count, p->output_section,
 448                                 p->needs_special_offset_handling,
 449                                 this->local_symbol_count_,
 450                                 local_symbols);
 451           if (parameters->options().emit_relocs())
 452             this->emit_relocs_scan(symtab, layout, local_symbols, p);
 453         }
 454       else
 455         {
 456           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 457           gold_assert(rr != NULL);
 458           rr->set_reloc_count(p->reloc_count);
 459           target->scan_relocatable_relocs(symtab, layout, this,
 460                                           p->data_shndx, p->sh_type,
 461                                           p->contents->data(),
 462                                           p->reloc_count,
 463                                           p->output_section,
 464                                           p->needs_special_offset_handling,
 465                                           this->local_symbol_count_,
 466                                           local_symbols,
 467                                           rr);
 468         }
 469
 470       delete p->contents;
 471       p->contents = NULL;
 472     }
 473
 474   if (rd->local_symbols != NULL)
 475     {
 476       delete rd->local_symbols;
 477       rd->local_symbols = NULL;
 478     }
 479 }
 480
 481 // This is a strategy class we use when scanning for --emit-relocs.
 482
 483 template<int sh_type>
 484 class Emit_relocs_strategy
 485 {
 486  public:
 487   // A local non-section symbol.
 488   inline Relocatable_relocs::Reloc_strategy
 489   local_non_section_strategy(unsigned int, Relobj*, unsigned int)
 490   { return Relocatable_relocs::RELOC_COPY; }
 491
 492   // A local section symbol.
 493   inline Relocatable_relocs::Reloc_strategy
 494   local_section_strategy(unsigned int, Relobj*)
 495   {
 496     if (sh_type == elfcpp::SHT_RELA)
 497       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 498     else
 499       {
 500         // The addend is stored in the section contents.  Since this
 501         // is not a relocatable link, we are going to apply the
 502         // relocation contents to the section as usual.  This means
 503         // that we have no way to record the original addend.  If the
 504         // original addend is not zero, there is basically no way for
 505         // the user to handle this correctly.  Caveat emptor.
 506         return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 507       }
 508   }
 509
 510   // A global symbol.
 511   inline Relocatable_relocs::Reloc_strategy
 512   global_strategy(unsigned int, Relobj*, unsigned int)
 513   { return Relocatable_relocs::RELOC_COPY; }
 514 };
 515
 516 // Scan the input relocations for --emit-relocs.
 517
 518 template<int size, bool big_endian>
 519 void
 520 Sized_relobj<size, big_endian>::emit_relocs_scan(
 521     Symbol_table* symtab,
 522     Layout* layout,
 523     const unsigned char* plocal_syms,
 524     const Read_relocs_data::Relocs_list::iterator& p)
 525 {
 526   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 527   gold_assert(rr != NULL);
 528   rr->set_reloc_count(p->reloc_count);
 529
 530   if (p->sh_type == elfcpp::SHT_REL)
 531     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(symtab, layout,
 532                                                     plocal_syms, p, rr);
 533   else
 534     {
 535       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 536       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(symtab, layout,
 537                                                        plocal_syms, p, rr);
 538     }
 539 }
 540
 541 // Scan the input relocation for --emit-relocs, templatized on the
 542 // type of the relocation section.
 543
 544 template<int size, bool big_endian>
 545 template<int sh_type>
 546 void
 547 Sized_relobj<size, big_endian>::emit_relocs_scan_reltype(
 548     Symbol_table* symtab,
 549     Layout* layout,
 550     const unsigned char* plocal_syms,
 551     const Read_relocs_data::Relocs_list::iterator& p,
 552     Relocatable_relocs* rr)
 553 {
 554   scan_relocatable_relocs<size, big_endian, sh_type,
 555                           Emit_relocs_strategy<sh_type> >(
 556     symtab,
 557     layout,
 558     this,
 559     p->data_shndx,
 560     p->contents->data(),
 561     p->reloc_count,
 562     p->output_section,
 563     p->needs_special_offset_handling,
 564     this->local_symbol_count_,
 565     plocal_syms,
 566     rr);
 567 }
 568
 569 // Relocate the input sections and write out the local symbols.
 570
 571 template<int size, bool big_endian>
 572 void
 573 Sized_relobj<size, big_endian>::do_relocate(const Symbol_table* symtab,
 574                                             const Layout* layout,
 575                                             Output_file* of)
 576 {
 577   unsigned int shnum = this->shnum();
 578
 579   // Read the section headers.
 580   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 581                                                shnum * This::shdr_size,
 582                                                true, true);
 583
 584   Views views;
 585   views.resize(shnum);
 586
 587   // Make two passes over the sections.  The first one copies the
 588   // section data to the output file.  The second one applies
 589   // relocations.
 590
 591   this->write_sections(pshdrs, of, &views);
 592
 593   // To speed up relocations, we set up hash tables for fast lookup of
 594   // input offsets to output addresses.
 595   this->initialize_input_to_output_maps();
 596
 597   // Apply relocations.
 598
 599   this->relocate_sections(symtab, layout, pshdrs, &views);
 600
 601   // After we've done the relocations, we release the hash tables,
 602   // since we no longer need them.
 603   this->free_input_to_output_maps();
 604
 605   // Write out the accumulated views.
 606   for (unsigned int i = 1; i < shnum; ++i)
 607     {
 608       if (views[i].view != NULL)
 609         {
 610           if (!views[i].is_postprocessing_view)
 611             {
 612               if (views[i].is_input_output_view)
 613                 of->write_input_output_view(views[i].offset,
 614                                             views[i].view_size,
 615                                             views[i].view);
 616               else
 617                 of->write_output_view(views[i].offset, views[i].view_size,
 618                                       views[i].view);
 619             }
 620         }
 621     }
 622
 623   // Write out the local symbols.
 624   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
 625                             layout->symtab_xindex(), layout->dynsym_xindex());
 626
 627   // We should no longer need the local symbol values.
 628   this->clear_local_symbols();
 629 }
 630
 631 // Sort a Read_multiple vector by file offset.
 632 struct Read_multiple_compare
 633 {
 634   inline bool
 635   operator()(const File_read::Read_multiple_entry& rme1,
 636              const File_read::Read_multiple_entry& rme2) const
 637   { return rme1.file_offset < rme2.file_offset; }
 638 };
 639
 640 // Write section data to the output file.  PSHDRS points to the
 641 // section headers.  Record the views in *PVIEWS for use when
 642 // relocating.
 643
 644 template<int size, bool big_endian>
 645 void
 646 Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
 647                                                Output_file* of,
 648                                                Views* pviews)
 649 {
 650   unsigned int shnum = this->shnum();
 651   const Output_sections& out_sections(this->output_sections());
 652   const std::vector<Address>& out_offsets(this->section_offsets_);
 653
 654   File_read::Read_multiple rm;
 655   bool is_sorted = true;
 656
 657   const unsigned char* p = pshdrs + This::shdr_size;
 658   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 659     {
 660       View_size* pvs = &(*pviews)[i];
 661
 662       pvs->view = NULL;
 663
 664       const Output_section* os = out_sections[i];
 665       if (os == NULL)
 666         continue;
 667       Address output_offset = out_offsets[i];
 668
 669       typename This::Shdr shdr(p);
 670
 671       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
 672         continue;
 673
 674       if ((parameters->options().relocatable()
 675            || parameters->options().emit_relocs())
 676           && (shdr.get_sh_type() == elfcpp::SHT_REL
 677               || shdr.get_sh_type() == elfcpp::SHT_RELA)
 678           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 679         {
 680           // This is a reloc section in a relocatable link or when
 681           // emitting relocs.  We don't need to read the input file.
 682           // The size and file offset are stored in the
 683           // Relocatable_relocs structure.
 684           Relocatable_relocs* rr = this->relocatable_relocs(i);
 685           gold_assert(rr != NULL);
 686           Output_data* posd = rr->output_data();
 687           gold_assert(posd != NULL);
 688
 689           pvs->offset = posd->offset();
 690           pvs->view_size = posd->data_size();
 691           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
 692           pvs->address = posd->address();
 693           pvs->is_input_output_view = false;
 694           pvs->is_postprocessing_view = false;
 695
 696           continue;
 697         }
 698
 699       // In the normal case, this input section is simply mapped to
 700       // the output section at offset OUTPUT_OFFSET.
 701
 702       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
 703       // handled specially--e.g., a .eh_frame section.  The relocation
 704       // routines need to check for each reloc where it should be
 705       // applied.  For this case, we need an input/output view for the
 706       // entire contents of the section in the output file.  We don't
 707       // want to copy the contents of the input section to the output
 708       // section; the output section contents were already written,
 709       // and we waited for them in Relocate_task::is_runnable because
 710       // relocs_must_follow_section_writes is set for the object.
 711
 712       // Regardless of which of the above cases is true, we have to
 713       // check requires_postprocessing of the output section.  If that
 714       // is false, then we work with views of the output file
 715       // directly.  If it is true, then we work with a separate
 716       // buffer, and the output section is responsible for writing the
 717       // final data to the output file.
 718
 719       off_t output_section_offset;
 720       Address output_section_size;
 721       if (!os->requires_postprocessing())
 722         {
 723           output_section_offset = os->offset();
 724           output_section_size = convert_types<Address, off_t>(os->data_size());
 725         }
 726       else
 727         {
 728           output_section_offset = 0;
 729           output_section_size =
 730               convert_types<Address, off_t>(os->postprocessing_buffer_size());
 731         }
 732
 733       off_t view_start;
 734       section_size_type view_size;
 735       if (output_offset != invalid_address)
 736         {
 737           view_start = output_section_offset + output_offset;
 738           view_size = convert_to_section_size_type(shdr.get_sh_size());
 739         }
 740       else
 741         {
 742           view_start = output_section_offset;
 743           view_size = convert_to_section_size_type(output_section_size);
 744         }
 745
 746       if (view_size == 0)
 747         continue;
 748
 749       gold_assert(output_offset == invalid_address
 750                   || output_offset + view_size <= output_section_size);
 751
 752       unsigned char* view;
 753       if (os->requires_postprocessing())
 754         {
 755           unsigned char* buffer = os->postprocessing_buffer();
 756           view = buffer + view_start;
 757           if (output_offset != invalid_address)
 758             {
 759               off_t sh_offset = shdr.get_sh_offset();
 760               if (!rm.empty() && rm.back().file_offset > sh_offset)
 761                 is_sorted = false;
 762               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 763                                                           view_size, view));
 764             }
 765         }
 766       else
 767         {
 768           if (output_offset == invalid_address)
 769             view = of->get_input_output_view(view_start, view_size);
 770           else
 771             {
 772               view = of->get_output_view(view_start, view_size);
 773               off_t sh_offset = shdr.get_sh_offset();
 774               if (!rm.empty() && rm.back().file_offset > sh_offset)
 775                 is_sorted = false;
 776               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 777                                                           view_size, view));
 778             }
 779         }
 780
 781       pvs->view = view;
 782       pvs->address = os->address();
 783       if (output_offset != invalid_address)
 784         pvs->address += output_offset;
 785       pvs->offset = view_start;
 786       pvs->view_size = view_size;
 787       pvs->is_input_output_view = output_offset == invalid_address;
 788       pvs->is_postprocessing_view = os->requires_postprocessing();
 789     }
 790
 791   // Actually read the data.
 792   if (!rm.empty())
 793     {
 794       if (!is_sorted)
 795         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
 796       this->read_multiple(rm);
 797     }
 798 }
 799
 800 // Relocate section data.  VIEWS points to the section data as views
 801 // in the output file.
 802
 803 template<int size, bool big_endian>
 804 void
 805 Sized_relobj<size, big_endian>::do_relocate_sections(
 806     const Symbol_table* symtab,
 807     const Layout* layout,
 808     const unsigned char* pshdrs,
 809     Views* pviews)
 810 {
 811   unsigned int shnum = this->shnum();
 812   Sized_target<size, big_endian>* target =
 813     parameters->sized_target<size, big_endian>();
 814
 815   const Output_sections& out_sections(this->output_sections());
 816   const std::vector<Address>& out_offsets(this->section_offsets_);
 817
 818   Relocate_info<size, big_endian> relinfo;
 819   relinfo.symtab = symtab;
 820   relinfo.layout = layout;
 821   relinfo.object = this;
 822
 823   const unsigned char* p = pshdrs + This::shdr_size;
 824   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 825     {
 826       typename This::Shdr shdr(p);
 827
 828       unsigned int sh_type = shdr.get_sh_type();
 829       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 830         continue;
 831
 832       off_t sh_size = shdr.get_sh_size();
 833       if (sh_size == 0)
 834         continue;
 835
 836       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
 837       if (index >= this->shnum())
 838         {
 839           this->error(_("relocation section %u has bad info %u"),
 840                       i, index);
 841           continue;
 842         }
 843
 844       Output_section* os = out_sections[index];
 845       if (os == NULL)
 846         {
 847           // This relocation section is against a section which we
 848           // discarded.
 849           continue;
 850         }
 851       Address output_offset = out_offsets[index];
 852
 853       gold_assert((*pviews)[index].view != NULL);
 854       if (parameters->options().relocatable())
 855         gold_assert((*pviews)[i].view != NULL);
 856
 857       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 858         {
 859           gold_error(_("relocation section %u uses unexpected "
 860                        "symbol table %u"),
 861                      i, this->adjust_shndx(shdr.get_sh_link()));
 862           continue;
 863         }
 864
 865       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
 866                                                     sh_size, true, false);
 867
 868       unsigned int reloc_size;
 869       if (sh_type == elfcpp::SHT_REL)
 870         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 871       else
 872         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 873
 874       if (reloc_size != shdr.get_sh_entsize())
 875         {
 876           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
 877                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 878                      reloc_size);
 879           continue;
 880         }
 881
 882       size_t reloc_count = sh_size / reloc_size;
 883       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 884         {
 885           gold_error(_("reloc section %u size %lu uneven"),
 886                      i, static_cast<unsigned long>(sh_size));
 887           continue;
 888         }
 889
 890       gold_assert(output_offset != invalid_address
 891                   || this->relocs_must_follow_section_writes());
 892
 893       relinfo.reloc_shndx = i;
 894       relinfo.reloc_shdr = p;
 895       relinfo.data_shndx = index;
 896       relinfo.data_shdr = pshdrs + index * This::shdr_size;
 897       unsigned char* view = (*pviews)[index].view;
 898       Address address = (*pviews)[index].address;
 899       section_size_type view_size = (*pviews)[index].view_size;
 900
 901       Reloc_symbol_changes* reloc_map = NULL;
 902       if (this->uses_split_stack() && output_offset != invalid_address)
 903         {
 904           typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
 905           if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
 906             this->split_stack_adjust(symtab, pshdrs, sh_type, index,
 907                                      prelocs, reloc_count, view, view_size,
 908                                      &reloc_map);
 909         }
 910
 911       if (!parameters->options().relocatable())
 912         {
 913           target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
 914                                    output_offset == invalid_address,
 915                                    view, address, view_size, reloc_map);
 916           if (parameters->options().emit_relocs())
 917             this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
 918                               os, output_offset, view, address, view_size,
 919                               (*pviews)[i].view, (*pviews)[i].view_size);
 920         }
 921       else
 922         {
 923           Relocatable_relocs* rr = this->relocatable_relocs(i);
 924           target->relocate_for_relocatable(&relinfo, sh_type, prelocs,
 925                                            reloc_count, os, output_offset, rr,
 926                                            view, address, view_size,
 927                                            (*pviews)[i].view,
 928                                            (*pviews)[i].view_size);
 929         }
 930     }
 931 }
 932
 933 // Emit the relocs for --emit-relocs.
 934
 935 template<int size, bool big_endian>
 936 void
 937 Sized_relobj<size, big_endian>::emit_relocs(
 938     const Relocate_info<size, big_endian>* relinfo,
 939     unsigned int i,
 940     unsigned int sh_type,
 941     const unsigned char* prelocs,
 942     size_t reloc_count,
 943     Output_section* output_section,
 944     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 945     unsigned char* view,
 946     typename elfcpp::Elf_types<size>::Elf_Addr address,
 947     section_size_type view_size,
 948     unsigned char* reloc_view,
 949     section_size_type reloc_view_size)
 950 {
 951   if (sh_type == elfcpp::SHT_REL)
 952     this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
 953                                                reloc_count, output_section,
 954                                                offset_in_output_section,
 955                                                view, address, view_size,
 956                                                reloc_view, reloc_view_size);
 957   else
 958     {
 959       gold_assert(sh_type == elfcpp::SHT_RELA);
 960       this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
 961                                                   reloc_count, output_section,
 962                                                   offset_in_output_section,
 963                                                   view, address, view_size,
 964                                                   reloc_view, reloc_view_size);
 965     }
 966 }
 967
 968 // Emit the relocs for --emit-relocs, templatized on the type of the
 969 // relocation section.
 970
 971 template<int size, bool big_endian>
 972 template<int sh_type>
 973 void
 974 Sized_relobj<size, big_endian>::emit_relocs_reltype(
 975     const Relocate_info<size, big_endian>* relinfo,
 976     unsigned int i,
 977     const unsigned char* prelocs,
 978     size_t reloc_count,
 979     Output_section* output_section,
 980     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 981     unsigned char* view,
 982     typename elfcpp::Elf_types<size>::Elf_Addr address,
 983     section_size_type view_size,
 984     unsigned char* reloc_view,
 985     section_size_type reloc_view_size)
 986 {
 987   const Relocatable_relocs* rr = this->relocatable_relocs(i);
 988   relocate_for_relocatable<size, big_endian, sh_type>(
 989     relinfo,
 990     prelocs,
 991     reloc_count,
 992     output_section,
 993     offset_in_output_section,
 994     rr,
 995     view,
 996     address,
 997     view_size,
 998     reloc_view,
 999     reloc_view_size);
1000 }
1001
1002 // Create merge hash tables for the local symbols.  These are used to
1003 // speed up relocations.
1004
1005 template<int size, bool big_endian>
1006 void
1007 Sized_relobj<size, big_endian>::initialize_input_to_output_maps()
1008 {
1009   const unsigned int loccount = this->local_symbol_count_;
1010   for (unsigned int i = 1; i < loccount; ++i)
1011     {
1012       Symbol_value<size>& lv(this->local_values_[i]);
1013       lv.initialize_input_to_output_map(this);
1014     }
1015 }
1016
1017 // Free merge hash tables for the local symbols.
1018
1019 template<int size, bool big_endian>
1020 void
1021 Sized_relobj<size, big_endian>::free_input_to_output_maps()
1022 {
1023   const unsigned int loccount = this->local_symbol_count_;
1024   for (unsigned int i = 1; i < loccount; ++i)
1025     {
1026       Symbol_value<size>& lv(this->local_values_[i]);
1027       lv.free_input_to_output_map();
1028     }
1029 }
1030
1031 // If an object was compiled with -fsplit-stack, this is called to
1032 // check whether any relocations refer to functions defined in objects
1033 // which were not compiled with -fsplit-stack.  If they were, then we
1034 // need to apply some target-specific adjustments to request
1035 // additional stack space.
1036
1037 template<int size, bool big_endian>
1038 void
1039 Sized_relobj<size, big_endian>::split_stack_adjust(
1040     const Symbol_table* symtab,
1041     const unsigned char* pshdrs,
1042     unsigned int sh_type,
1043     unsigned int shndx,
1044     const unsigned char* prelocs,
1045     size_t reloc_count,
1046     unsigned char* view,
1047     section_size_type view_size,
1048     Reloc_symbol_changes** reloc_map)
1049 {
1050   if (sh_type == elfcpp::SHT_REL)
1051     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1052                                                       prelocs, reloc_count,
1053                                                       view, view_size,
1054                                                       reloc_map);
1055   else
1056     {
1057       gold_assert(sh_type == elfcpp::SHT_RELA);
1058       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1059                                                          prelocs, reloc_count,
1060                                                          view, view_size,
1061                                                          reloc_map);
1062     }
1063 }
1064
1065 // Adjust for -fsplit-stack, templatized on the type of the relocation
1066 // section.
1067
1068 template<int size, bool big_endian>
1069 template<int sh_type>
1070 void
1071 Sized_relobj<size, big_endian>::split_stack_adjust_reltype(
1072     const Symbol_table* symtab,
1073     const unsigned char* pshdrs,
1074     unsigned int shndx,
1075     const unsigned char* prelocs,
1076     size_t reloc_count,
1077     unsigned char* view,
1078     section_size_type view_size,
1079     Reloc_symbol_changes** reloc_map)
1080 {
1081   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1082   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1083
1084   size_t local_count = this->local_symbol_count();
1085
1086   std::vector<section_offset_type> non_split_refs;
1087
1088   const unsigned char* pr = prelocs;
1089   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1090     {
1091       Reltype reloc(pr);
1092
1093       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1094       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1095       if (r_sym < local_count)
1096         continue;
1097
1098       const Symbol* gsym = this->global_symbol(r_sym);
1099       gold_assert(gsym != NULL);
1100       if (gsym->is_forwarder())
1101         gsym = symtab->resolve_forwards(gsym);
1102
1103       // See if this relocation refers to a function defined in an
1104       // object compiled without -fsplit-stack.  Note that we don't
1105       // care about the type of relocation--this means that in some
1106       // cases we will ask for a large stack unnecessarily, but this
1107       // is not fatal.  FIXME: Some targets have symbols which are
1108       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1109       if (gsym->type() == elfcpp::STT_FUNC
1110           && !gsym->is_undefined()
1111           && gsym->source() == Symbol::FROM_OBJECT
1112           && !gsym->object()->uses_split_stack())
1113         {
1114           section_offset_type offset =
1115             convert_to_section_size_type(reloc.get_r_offset());
1116           non_split_refs.push_back(offset);
1117         }
1118     }
1119
1120   if (non_split_refs.empty())
1121     return;
1122
1123   // At this point, every entry in NON_SPLIT_REFS indicates a
1124   // relocation which refers to a function in an object compiled
1125   // without -fsplit-stack.  We now have to convert that list into a
1126   // set of offsets to functions.  First, we find all the functions.
1127
1128   Function_offsets function_offsets;
1129   this->find_functions(pshdrs, shndx, &function_offsets);
1130   if (function_offsets.empty())
1131     return;
1132
1133   // Now get a list of the function with references to non split-stack
1134   // code.
1135
1136   Function_offsets calls_non_split;
1137   for (std::vector<section_offset_type>::const_iterator p
1138          = non_split_refs.begin();
1139        p != non_split_refs.end();
1140        ++p)
1141     {
1142       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1143       if (low == function_offsets.end())
1144         --low;
1145       else if (low->first == *p)
1146         ;
1147       else if (low == function_offsets.begin())
1148         continue;
1149       else
1150         --low;
1151
1152       calls_non_split.insert(*low);
1153     }
1154   if (calls_non_split.empty())
1155     return;
1156
1157   // Now we have a set of functions to adjust.  The adjustments are
1158   // target specific.  Besides changing the output section view
1159   // however, it likes, the target may request a relocation change
1160   // from one global symbol name to another.
1161
1162   for (Function_offsets::const_iterator p = calls_non_split.begin();
1163        p != calls_non_split.end();
1164        ++p)
1165     {
1166       std::string from;
1167       std::string to;
1168       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1169                                            view, view_size, &from, &to);
1170       if (!from.empty())
1171         {
1172           gold_assert(!to.empty());
1173           Symbol* tosym = NULL;
1174
1175           // Find relocations in the relevant function which are for
1176           // FROM.
1177           pr = prelocs;
1178           for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1179             {
1180               Reltype reloc(pr);
1181
1182               typename elfcpp::Elf_types<size>::Elf_WXword r_info =
1183                 reloc.get_r_info();
1184               unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1185               if (r_sym < local_count)
1186                 continue;
1187
1188               section_offset_type offset =
1189                 convert_to_section_size_type(reloc.get_r_offset());
1190               if (offset < p->first
1191                   || (offset
1192                       >= (p->first
1193                           + static_cast<section_offset_type>(p->second))))
1194                 continue;
1195
1196               const Symbol* gsym = this->global_symbol(r_sym);
1197               if (from == gsym->name())
1198                 {
1199                   if (tosym == NULL)
1200                     {
1201                       tosym = symtab->lookup(to.c_str());
1202                       if (tosym == NULL)
1203                         {
1204                           this->error(_("could not convert call "
1205                                         "to '%s' to '%s'"),
1206                                       from.c_str(), to.c_str());
1207                           break;
1208                         }
1209                     }
1210
1211                   if (*reloc_map == NULL)
1212                     *reloc_map = new Reloc_symbol_changes(reloc_count);
1213                   (*reloc_map)->set(i, tosym);
1214                 }
1215             }
1216         }
1217     }
1218 }
1219
1220 // Find all the function in this object defined in section SHNDX.
1221 // Store their offsets in the section in FUNCTION_OFFSETS.
1222
1223 template<int size, bool big_endian>
1224 void
1225 Sized_relobj<size, big_endian>::find_functions(
1226     const unsigned char* pshdrs,
1227     unsigned int shndx,
1228     Sized_relobj<size, big_endian>::Function_offsets* function_offsets)
1229 {
1230   // We need to read the symbols to find the functions.  If we wanted
1231   // to, we could cache reading the symbols across all sections in the
1232   // object.
1233   const unsigned int symtab_shndx = this->symtab_shndx_;
1234   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1235   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1236
1237   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1238     symtabshdr.get_sh_size();
1239   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1240                                               sh_size, true, true);
1241
1242   const int sym_size = This::sym_size;
1243   const unsigned int symcount = sh_size / sym_size;
1244   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1245     {
1246       typename elfcpp::Sym<size, big_endian> isym(psyms);
1247
1248       // FIXME: Some targets can have functions which do not have type
1249       // STT_FUNC, e.g., STT_ARM_TFUNC.
1250       if (isym.get_st_type() != elfcpp::STT_FUNC
1251           || isym.get_st_size() == 0)
1252         continue;
1253
1254       bool is_ordinary;
1255       unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1256                                                       &is_ordinary);
1257       if (!is_ordinary || sym_shndx != shndx)
1258         continue;
1259
1260       section_offset_type value =
1261         convert_to_section_size_type(isym.get_st_value());
1262       section_size_type fnsize =
1263         convert_to_section_size_type(isym.get_st_size());
1264
1265       (*function_offsets)[value] = fnsize;
1266     }
1267 }
1268
1269 // Class Merged_symbol_value.
1270
1271 template<int size>
1272 void
1273 Merged_symbol_value<size>::initialize_input_to_output_map(
1274     const Relobj* object,
1275     unsigned int input_shndx)
1276 {
1277   Object_merge_map* map = object->merge_map();
1278   map->initialize_input_to_output_map<size>(input_shndx,
1279                                             this->output_start_address_,
1280                                             &this->output_addresses_);
1281 }
1282
1283 // Get the output value corresponding to an input offset if we
1284 // couldn't find it in the hash table.
1285
1286 template<int size>
1287 typename elfcpp::Elf_types<size>::Elf_Addr
1288 Merged_symbol_value<size>::value_from_output_section(
1289     const Relobj* object,
1290     unsigned int input_shndx,
1291     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1292 {
1293   section_offset_type output_offset;
1294   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
1295                                                       input_offset,
1296                                                       &output_offset);
1297
1298   // If this assertion fails, it means that some relocation was
1299   // against a portion of an input merge section which we didn't map
1300   // to the output file and we didn't explicitly discard.  We should
1301   // always map all portions of input merge sections.
1302   gold_assert(found);
1303
1304   if (output_offset == -1)
1305     return 0;
1306   else
1307     return this->output_start_address_ + output_offset;
1308 }
1309
1310 // Track_relocs methods.
1311
1312 // Initialize the class to track the relocs.  This gets the object,
1313 // the reloc section index, and the type of the relocs.  This returns
1314 // false if something goes wrong.
1315
1316 template<int size, bool big_endian>
1317 bool
1318 Track_relocs<size, big_endian>::initialize(
1319     Object* object,
1320     unsigned int reloc_shndx,
1321     unsigned int reloc_type)
1322 {
1323   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1324   // section for the .eh_frame section.  We can't handle that case.
1325   if (reloc_shndx == -1U)
1326     return false;
1327
1328   // If RELOC_SHNDX is 0, there is no reloc section.
1329   if (reloc_shndx == 0)
1330     return true;
1331
1332   // Get the contents of the reloc section.
1333   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1334
1335   if (reloc_type == elfcpp::SHT_REL)
1336     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1337   else if (reloc_type == elfcpp::SHT_RELA)
1338     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1339   else
1340     gold_unreachable();
1341
1342   if (this->len_ % this->reloc_size_ != 0)
1343     {
1344       object->error(_("reloc section size %zu is not a multiple of "
1345                       "reloc size %d\n"),
1346                     static_cast<size_t>(this->len_),
1347                     this->reloc_size_);
1348       return false;
1349     }
1350
1351   return true;
1352 }
1353
1354 // Return the offset of the next reloc, or -1 if there isn't one.
1355
1356 template<int size, bool big_endian>
1357 off_t
1358 Track_relocs<size, big_endian>::next_offset() const
1359 {
1360   if (this->pos_ >= this->len_)
1361     return -1;
1362
1363   // Rel and Rela start out the same, so we can always use Rel to find
1364   // the r_offset value.
1365   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1366   return rel.get_r_offset();
1367 }
1368
1369 // Return the index of the symbol referenced by the next reloc, or -1U
1370 // if there aren't any more relocs.
1371
1372 template<int size, bool big_endian>
1373 unsigned int
1374 Track_relocs<size, big_endian>::next_symndx() const
1375 {
1376   if (this->pos_ >= this->len_)
1377     return -1U;
1378
1379   // Rel and Rela start out the same, so we can use Rel to find the
1380   // symbol index.
1381   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1382   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1383 }
1384
1385 // Advance to the next reloc whose r_offset is greater than or equal
1386 // to OFFSET.  Return the number of relocs we skip.
1387
1388 template<int size, bool big_endian>
1389 int
1390 Track_relocs<size, big_endian>::advance(off_t offset)
1391 {
1392   int ret = 0;
1393   while (this->pos_ < this->len_)
1394     {
1395       // Rel and Rela start out the same, so we can always use Rel to
1396       // find the r_offset value.
1397       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1398       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1399         break;
1400       ++ret;
1401       this->pos_ += this->reloc_size_;
1402     }
1403   return ret;
1404 }
1405
1406 // Instantiate the templates we need.
1407
1408 #ifdef HAVE_TARGET_32_LITTLE
1409 template
1410 void
1411 Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
1412 #endif
1413
1414 #ifdef HAVE_TARGET_32_BIG
1415 template
1416 void
1417 Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
1418 #endif
1419
1420 #ifdef HAVE_TARGET_64_LITTLE
1421 template
1422 void
1423 Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
1424 #endif
1425
1426 #ifdef HAVE_TARGET_64_BIG
1427 template
1428 void
1429 Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
1430 #endif
1431
1432 #ifdef HAVE_TARGET_32_LITTLE
1433 template
1434 void
1435 Sized_relobj<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1436                                               Layout* layout,
1437                                               Read_relocs_data* rd);
1438 #endif
1439
1440 #ifdef HAVE_TARGET_32_BIG
1441 template
1442 void
1443 Sized_relobj<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1444                                              Layout* layout,
1445                                              Read_relocs_data* rd);
1446 #endif
1447
1448 #ifdef HAVE_TARGET_64_LITTLE
1449 template
1450 void
1451 Sized_relobj<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1452                                               Layout* layout,
1453                                               Read_relocs_data* rd);
1454 #endif
1455
1456 #ifdef HAVE_TARGET_64_BIG
1457 template
1458 void
1459 Sized_relobj<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1460                                              Layout* layout,
1461                                              Read_relocs_data* rd);
1462 #endif
1463
1464 #ifdef HAVE_TARGET_32_LITTLE
1465 template
1466 void
1467 Sized_relobj<32, false>::do_scan_relocs(Symbol_table* symtab,
1468                                         Layout* layout,
1469                                         Read_relocs_data* rd);
1470 #endif
1471
1472 #ifdef HAVE_TARGET_32_BIG
1473 template
1474 void
1475 Sized_relobj<32, true>::do_scan_relocs(Symbol_table* symtab,
1476                                        Layout* layout,
1477                                        Read_relocs_data* rd);
1478 #endif
1479
1480 #ifdef HAVE_TARGET_64_LITTLE
1481 template
1482 void
1483 Sized_relobj<64, false>::do_scan_relocs(Symbol_table* symtab,
1484                                         Layout* layout,
1485                                         Read_relocs_data* rd);
1486 #endif
1487
1488 #ifdef HAVE_TARGET_64_BIG
1489 template
1490 void
1491 Sized_relobj<64, true>::do_scan_relocs(Symbol_table* symtab,
1492                                        Layout* layout,
1493                                        Read_relocs_data* rd);
1494 #endif
1495
1496 #ifdef HAVE_TARGET_32_LITTLE
1497 template
1498 void
1499 Sized_relobj<32, false>::do_relocate(const Symbol_table* symtab,
1500                                      const Layout* layout,
1501                                      Output_file* of);
1502 #endif
1503
1504 #ifdef HAVE_TARGET_32_BIG
1505 template
1506 void
1507 Sized_relobj<32, true>::do_relocate(const Symbol_table* symtab,
1508                                     const Layout* layout,
1509                                     Output_file* of);
1510 #endif
1511
1512 #ifdef HAVE_TARGET_64_LITTLE
1513 template
1514 void
1515 Sized_relobj<64, false>::do_relocate(const Symbol_table* symtab,
1516                                      const Layout* layout,
1517                                      Output_file* of);
1518 #endif
1519
1520 #ifdef HAVE_TARGET_64_BIG
1521 template
1522 void
1523 Sized_relobj<64, true>::do_relocate(const Symbol_table* symtab,
1524                                     const Layout* layout,
1525                                     Output_file* of);
1526 #endif
1527
1528 #ifdef HAVE_TARGET_32_LITTLE
1529 template
1530 void
1531 Sized_relobj<32, false>::do_relocate_sections(
1532     const Symbol_table* symtab,
1533     const Layout* layout,
1534     const unsigned char* pshdrs,
1535     Views* pviews);
1536 #endif
1537
1538 #ifdef HAVE_TARGET_32_BIG
1539 template
1540 void
1541 Sized_relobj<32, true>::do_relocate_sections(
1542     const Symbol_table* symtab,
1543     const Layout* layout,
1544     const unsigned char* pshdrs,
1545     Views* pviews);
1546 #endif
1547
1548 #ifdef HAVE_TARGET_64_LITTLE
1549 template
1550 void
1551 Sized_relobj<64, false>::do_relocate_sections(
1552     const Symbol_table* symtab,
1553     const Layout* layout,
1554     const unsigned char* pshdrs,
1555     Views* pviews);
1556 #endif
1557
1558 #ifdef HAVE_TARGET_64_BIG
1559 template
1560 void
1561 Sized_relobj<64, true>::do_relocate_sections(
1562     const Symbol_table* symtab,
1563     const Layout* layout,
1564     const unsigned char* pshdrs,
1565     Views* pviews);
1566 #endif
1567
1568 #ifdef HAVE_TARGET_32_LITTLE
1569 template
1570 void
1571 Sized_relobj<32, false>::initialize_input_to_output_maps();
1572
1573 template
1574 void
1575 Sized_relobj<32, false>::free_input_to_output_maps();
1576 #endif
1577
1578 #ifdef HAVE_TARGET_32_BIG
1579 template
1580 void
1581 Sized_relobj<32, true>::initialize_input_to_output_maps();
1582
1583 template
1584 void
1585 Sized_relobj<32, true>::free_input_to_output_maps();
1586 #endif
1587
1588 #ifdef HAVE_TARGET_64_LITTLE
1589 template
1590 void
1591 Sized_relobj<64, false>::initialize_input_to_output_maps();
1592
1593 template
1594 void
1595 Sized_relobj<64, false>::free_input_to_output_maps();
1596 #endif
1597
1598 #ifdef HAVE_TARGET_64_BIG
1599 template
1600 void
1601 Sized_relobj<64, true>::initialize_input_to_output_maps();
1602
1603 template
1604 void
1605 Sized_relobj<64, true>::free_input_to_output_maps();
1606 #endif
1607
1608 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1609 template
1610 class Merged_symbol_value<32>;
1611 #endif
1612
1613 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1614 template
1615 class Merged_symbol_value<64>;
1616 #endif
1617
1618 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1619 template
1620 class Symbol_value<32>;
1621 #endif
1622
1623 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1624 template
1625 class Symbol_value<64>;
1626 #endif
1627
1628 #ifdef HAVE_TARGET_32_LITTLE
1629 template
1630 class Track_relocs<32, false>;
1631 #endif
1632
1633 #ifdef HAVE_TARGET_32_BIG
1634 template
1635 class Track_relocs<32, true>;
1636 #endif
1637
1638 #ifdef HAVE_TARGET_64_LITTLE
1639 template
1640 class Track_relocs<64, false>;
1641 #endif
1642
1643 #ifdef HAVE_TARGET_64_BIG
1644 template
1645 class Track_relocs<64, true>;
1646 #endif
1647
1648 } // End namespace gold.