gold/reloc.cc

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