gold/reloc.cc

   1 // reloc.cc -- relocate input files for gold.
   2
   3 // Copyright 2006, 2007, 2008 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
  35 namespace gold
  36 {
  37
  38 // Read_relocs methods.
  39
  40 // These tasks just read the relocation information from the file.
  41 // After reading it, the start another task to process the
  42 // information.  These tasks requires access to the file.
  43
  44 Task_token*
  45 Read_relocs::is_runnable()
  46 {
  47   return this->object_->is_locked() ? this->object_->token() : NULL;
  48 }
  49
  50 // Lock the file.
  51
  52 void
  53 Read_relocs::locks(Task_locker* tl)
  54 {
  55   tl->add(this, this->object_->token());
  56 }
  57
  58 // Read the relocations and then start a Scan_relocs_task.
  59
  60 void
  61 Read_relocs::run(Workqueue* workqueue)
  62 {
  63   Read_relocs_data *rd = new Read_relocs_data;
  64   this->object_->read_relocs(rd);
  65   this->object_->release();
  66
  67   workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
  68                                         this->layout_, this->object_, rd,
  69                                         this->symtab_lock_, this->blocker_));
  70 }
  71
  72 // Return a debugging name for the task.
  73
  74 std::string
  75 Read_relocs::get_name() const
  76 {
  77   return "Read_relocs " + this->object_->name();
  78 }
  79
  80 // Scan_relocs methods.
  81
  82 // These tasks scan the relocations read by Read_relocs and mark up
  83 // the symbol table to indicate which relocations are required.  We
  84 // use a lock on the symbol table to keep them from interfering with
  85 // each other.
  86
  87 Task_token*
  88 Scan_relocs::is_runnable()
  89 {
  90   if (!this->symtab_lock_->is_writable())
  91     return this->symtab_lock_;
  92   if (this->object_->is_locked())
  93     return this->object_->token();
  94   return NULL;
  95 }
  96
  97 // Return the locks we hold: one on the file, one on the symbol table
  98 // and one blocker.
  99
 100 void
 101 Scan_relocs::locks(Task_locker* tl)
 102 {
 103   tl->add(this, this->object_->token());
 104   tl->add(this, this->symtab_lock_);
 105   tl->add(this, this->blocker_);
 106 }
 107
 108 // Scan the relocs.
 109
 110 void
 111 Scan_relocs::run(Workqueue*)
 112 {
 113   this->object_->scan_relocs(this->options_, this->symtab_, this->layout_,
 114                              this->rd_);
 115   this->object_->release();
 116   delete this->rd_;
 117   this->rd_ = NULL;
 118 }
 119
 120 // Return a debugging name for the task.
 121
 122 std::string
 123 Scan_relocs::get_name() const
 124 {
 125   return "Scan_relocs " + this->object_->name();
 126 }
 127
 128 // Relocate_task methods.
 129
 130 // We may have to wait for the output sections to be written.
 131
 132 Task_token*
 133 Relocate_task::is_runnable()
 134 {
 135   if (this->object_->relocs_must_follow_section_writes()
 136       && this->output_sections_blocker_->is_blocked())
 137     return this->output_sections_blocker_;
 138
 139   if (this->object_->is_locked())
 140     return this->object_->token();
 141
 142   return NULL;
 143 }
 144
 145 // We want to lock the file while we run.  We want to unblock
 146 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
 147 // INPUT_SECTIONS_BLOCKER may be NULL.
 148
 149 void
 150 Relocate_task::locks(Task_locker* tl)
 151 {
 152   if (this->input_sections_blocker_ != NULL)
 153     tl->add(this, this->input_sections_blocker_);
 154   tl->add(this, this->final_blocker_);
 155   tl->add(this, this->object_->token());
 156 }
 157
 158 // Run the task.
 159
 160 void
 161 Relocate_task::run(Workqueue*)
 162 {
 163   this->object_->relocate(this->options_, this->symtab_, this->layout_,
 164                           this->of_);
 165
 166   // This is normally the last thing we will do with an object, so
 167   // uncache all views.
 168   this->object_->clear_view_cache_marks();
 169
 170   this->object_->release();
 171 }
 172
 173 // Return a debugging name for the task.
 174
 175 std::string
 176 Relocate_task::get_name() const
 177 {
 178   return "Relocate_task " + this->object_->name();
 179 }
 180
 181 // Read the relocs and local symbols from the object file and store
 182 // the information in RD.
 183
 184 template<int size, bool big_endian>
 185 void
 186 Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
 187 {
 188   rd->relocs.clear();
 189
 190   unsigned int shnum = this->shnum();
 191   if (shnum == 0)
 192     return;
 193
 194   rd->relocs.reserve(shnum / 2);
 195
 196   const Output_sections& out_sections(this->output_sections());
 197   const std::vector<Address>& out_offsets(this->section_offsets_);
 198
 199   const unsigned char *pshdrs = this->get_view(this->elf_file_.shoff(),
 200                                                shnum * This::shdr_size,
 201                                                true, true);
 202   // Skip the first, dummy, section.
 203   const unsigned char *ps = pshdrs + This::shdr_size;
 204   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
 205     {
 206       typename This::Shdr shdr(ps);
 207
 208       unsigned int sh_type = shdr.get_sh_type();
 209       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 210         continue;
 211
 212       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
 213       if (shndx >= shnum)
 214         {
 215           this->error(_("relocation section %u has bad info %u"),
 216                       i, shndx);
 217           continue;
 218         }
 219
 220       Output_section* os = out_sections[shndx];
 221       if (os == NULL)
 222         continue;
 223
 224       // We are scanning relocations in order to fill out the GOT and
 225       // PLT sections.  Relocations for sections which are not
 226       // allocated (typically debugging sections) should not add new
 227       // GOT and PLT entries.  So we skip them unless this is a
 228       // relocatable link or we need to emit relocations.
 229       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
 230       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
 231                                    != 0);
 232       if (!is_section_allocated
 233           && !parameters->options().relocatable()
 234           && !parameters->options().emit_relocs())
 235         continue;
 236
 237       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 238         {
 239           this->error(_("relocation section %u uses unexpected "
 240                         "symbol table %u"),
 241                       i, this->adjust_shndx(shdr.get_sh_link()));
 242           continue;
 243         }
 244
 245       off_t sh_size = shdr.get_sh_size();
 246
 247       unsigned int reloc_size;
 248       if (sh_type == elfcpp::SHT_REL)
 249         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 250       else
 251         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 252       if (reloc_size != shdr.get_sh_entsize())
 253         {
 254           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
 255                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 256                       reloc_size);
 257           continue;
 258         }
 259
 260       size_t reloc_count = sh_size / reloc_size;
 261       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 262         {
 263           this->error(_("reloc section %u size %lu uneven"),
 264                       i, static_cast<unsigned long>(sh_size));
 265           continue;
 266         }
 267
 268       rd->relocs.push_back(Section_relocs());
 269       Section_relocs& sr(rd->relocs.back());
 270       sr.reloc_shndx = i;
 271       sr.data_shndx = shndx;
 272       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
 273                                            true, true);
 274       sr.sh_type = sh_type;
 275       sr.reloc_count = reloc_count;
 276       sr.output_section = os;
 277       sr.needs_special_offset_handling = out_offsets[shndx] == -1U;
 278       sr.is_data_section_allocated = is_section_allocated;
 279     }
 280
 281   // Read the local symbols.
 282   gold_assert(this->symtab_shndx_ != -1U);
 283   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
 284     rd->local_symbols = NULL;
 285   else
 286     {
 287       typename This::Shdr symtabshdr(pshdrs
 288                                      + this->symtab_shndx_ * This::shdr_size);
 289       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
 290       const int sym_size = This::sym_size;
 291       const unsigned int loccount = this->local_symbol_count_;
 292       gold_assert(loccount == symtabshdr.get_sh_info());
 293       off_t locsize = loccount * sym_size;
 294       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
 295                                                  locsize, true, true);
 296     }
 297 }
 298
 299 // Scan the relocs and adjust the symbol table.  This looks for
 300 // relocations which require GOT/PLT/COPY relocations.
 301
 302 template<int size, bool big_endian>
 303 void
 304 Sized_relobj<size, big_endian>::do_scan_relocs(const General_options& options,
 305                                                Symbol_table* symtab,
 306                                                Layout* layout,
 307                                                Read_relocs_data* rd)
 308 {
 309   Sized_target<size, big_endian>* target = this->sized_target();
 310
 311   const unsigned char* local_symbols;
 312   if (rd->local_symbols == NULL)
 313     local_symbols = NULL;
 314   else
 315     local_symbols = rd->local_symbols->data();
 316
 317   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 318        p != rd->relocs.end();
 319        ++p)
 320     {
 321       if (!parameters->options().relocatable())
 322         {
 323           // As noted above, when not generating an object file, we
 324           // only scan allocated sections.  We may see a non-allocated
 325           // section here if we are emitting relocs.
 326           if (p->is_data_section_allocated)
 327             target->scan_relocs(options, symtab, layout, this, p->data_shndx,
 328                                 p->sh_type, p->contents->data(),
 329                                 p->reloc_count, p->output_section,
 330                                 p->needs_special_offset_handling,
 331                                 this->local_symbol_count_,
 332                                 local_symbols);
 333           if (parameters->options().emit_relocs())
 334             this->emit_relocs_scan(options, symtab, layout, local_symbols, p);
 335         }
 336       else
 337         {
 338           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 339           gold_assert(rr != NULL);
 340           rr->set_reloc_count(p->reloc_count);
 341           target->scan_relocatable_relocs(options, symtab, layout, this,
 342                                           p->data_shndx, p->sh_type,
 343                                           p->contents->data(),
 344                                           p->reloc_count,
 345                                           p->output_section,
 346                                           p->needs_special_offset_handling,
 347                                           this->local_symbol_count_,
 348                                           local_symbols,
 349                                           rr);
 350         }
 351
 352       delete p->contents;
 353       p->contents = NULL;
 354     }
 355
 356   if (rd->local_symbols != NULL)
 357     {
 358       delete rd->local_symbols;
 359       rd->local_symbols = NULL;
 360     }
 361 }
 362
 363 // This is a strategy class we use when scanning for --emit-relocs.
 364
 365 template<int sh_type>
 366 class Emit_relocs_strategy
 367 {
 368  public:
 369   // A local non-section symbol.
 370   inline Relocatable_relocs::Reloc_strategy
 371   local_non_section_strategy(unsigned int, Relobj*)
 372   { return Relocatable_relocs::RELOC_COPY; }
 373
 374   // A local section symbol.
 375   inline Relocatable_relocs::Reloc_strategy
 376   local_section_strategy(unsigned int, Relobj*)
 377   {
 378     if (sh_type == elfcpp::SHT_RELA)
 379       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 380     else
 381       {
 382         // The addend is stored in the section contents.  Since this
 383         // is not a relocatable link, we are going to apply the
 384         // relocation contents to the section as usual.  This means
 385         // that we have no way to record the original addend.  If the
 386         // original addend is not zero, there is basically no way for
 387         // the user to handle this correctly.  Caveat emptor.
 388         return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 389       }
 390   }
 391
 392   // A global symbol.
 393   inline Relocatable_relocs::Reloc_strategy
 394   global_strategy(unsigned int, Relobj*, unsigned int)
 395   { return Relocatable_relocs::RELOC_COPY; }
 396 };
 397
 398 // Scan the input relocations for --emit-relocs.
 399
 400 template<int size, bool big_endian>
 401 void
 402 Sized_relobj<size, big_endian>::emit_relocs_scan(
 403     const General_options& options,
 404     Symbol_table* symtab,
 405     Layout* layout,
 406     const unsigned char* plocal_syms,
 407     const Read_relocs_data::Relocs_list::iterator& p)
 408 {
 409   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 410   gold_assert(rr != NULL);
 411   rr->set_reloc_count(p->reloc_count);
 412
 413   if (p->sh_type == elfcpp::SHT_REL)
 414     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(options, symtab, layout,
 415                                                     plocal_syms, p, rr);
 416   else
 417     {
 418       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 419       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(options, symtab,
 420                                                        layout, plocal_syms, p,
 421                                                        rr);
 422     }
 423 }
 424
 425 // Scan the input relocation for --emit-relocs, templatized on the
 426 // type of the relocation section.
 427
 428 template<int size, bool big_endian>
 429 template<int sh_type>
 430 void
 431 Sized_relobj<size, big_endian>::emit_relocs_scan_reltype(
 432     const General_options& options,
 433     Symbol_table* symtab,
 434     Layout* layout,
 435     const unsigned char* plocal_syms,
 436     const Read_relocs_data::Relocs_list::iterator& p,
 437     Relocatable_relocs* rr)
 438 {
 439   scan_relocatable_relocs<size, big_endian, sh_type,
 440                           Emit_relocs_strategy<sh_type> >(
 441     options,
 442     symtab,
 443     layout,
 444     this,
 445     p->data_shndx,
 446     p->contents->data(),
 447     p->reloc_count,
 448     p->output_section,
 449     p->needs_special_offset_handling,
 450     this->local_symbol_count_,
 451     plocal_syms,
 452     rr);
 453 }
 454
 455 // Relocate the input sections and write out the local symbols.
 456
 457 template<int size, bool big_endian>
 458 void
 459 Sized_relobj<size, big_endian>::do_relocate(const General_options& options,
 460                                             const Symbol_table* symtab,
 461                                             const Layout* layout,
 462                                             Output_file* of)
 463 {
 464   unsigned int shnum = this->shnum();
 465
 466   // Read the section headers.
 467   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 468                                                shnum * This::shdr_size,
 469                                                true, true);
 470
 471   Views views;
 472   views.resize(shnum);
 473
 474   // Make two passes over the sections.  The first one copies the
 475   // section data to the output file.  The second one applies
 476   // relocations.
 477
 478   this->write_sections(pshdrs, of, &views);
 479
 480   // To speed up relocations, we set up hash tables for fast lookup of
 481   // input offsets to output addresses.
 482   this->initialize_input_to_output_maps();
 483
 484   // Apply relocations.
 485
 486   this->relocate_sections(options, symtab, layout, pshdrs, &views);
 487
 488   // After we've done the relocations, we release the hash tables,
 489   // since we no longer need them.
 490   this->free_input_to_output_maps();
 491
 492   // Write out the accumulated views.
 493   for (unsigned int i = 1; i < shnum; ++i)
 494     {
 495       if (views[i].view != NULL)
 496         {
 497           if (!views[i].is_postprocessing_view)
 498             {
 499               if (views[i].is_input_output_view)
 500                 of->write_input_output_view(views[i].offset,
 501                                             views[i].view_size,
 502                                             views[i].view);
 503               else
 504                 of->write_output_view(views[i].offset, views[i].view_size,
 505                                       views[i].view);
 506             }
 507         }
 508     }
 509
 510   // Write out the local symbols.
 511   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
 512                             layout->symtab_xindex(), layout->dynsym_xindex());
 513
 514   // We should no longer need the local symbol values.
 515   this->clear_local_symbols();
 516 }
 517
 518 // Sort a Read_multiple vector by file offset.
 519 struct Read_multiple_compare
 520 {
 521   inline bool
 522   operator()(const File_read::Read_multiple_entry& rme1,
 523              const File_read::Read_multiple_entry& rme2) const
 524   { return rme1.file_offset < rme2.file_offset; }
 525 };
 526
 527 // Write section data to the output file.  PSHDRS points to the
 528 // section headers.  Record the views in *PVIEWS for use when
 529 // relocating.
 530
 531 template<int size, bool big_endian>
 532 void
 533 Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
 534                                                Output_file* of,
 535                                                Views* pviews)
 536 {
 537   unsigned int shnum = this->shnum();
 538   const Output_sections& out_sections(this->output_sections());
 539   const std::vector<Address>& out_offsets(this->section_offsets_);
 540
 541   File_read::Read_multiple rm;
 542   bool is_sorted = true;
 543
 544   const unsigned char* p = pshdrs + This::shdr_size;
 545   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 546     {
 547       View_size* pvs = &(*pviews)[i];
 548
 549       pvs->view = NULL;
 550
 551       const Output_section* os = out_sections[i];
 552       if (os == NULL)
 553         continue;
 554       Address output_offset = out_offsets[i];
 555
 556       typename This::Shdr shdr(p);
 557
 558       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
 559         continue;
 560
 561       if ((parameters->options().relocatable()
 562            || parameters->options().emit_relocs())
 563           && (shdr.get_sh_type() == elfcpp::SHT_REL
 564               || shdr.get_sh_type() == elfcpp::SHT_RELA)
 565           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 566         {
 567           // This is a reloc section in a relocatable link or when
 568           // emitting relocs.  We don't need to read the input file.
 569           // The size and file offset are stored in the
 570           // Relocatable_relocs structure.
 571           Relocatable_relocs* rr = this->relocatable_relocs(i);
 572           gold_assert(rr != NULL);
 573           Output_data* posd = rr->output_data();
 574           gold_assert(posd != NULL);
 575
 576           pvs->offset = posd->offset();
 577           pvs->view_size = posd->data_size();
 578           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
 579           pvs->address = posd->address();
 580           pvs->is_input_output_view = false;
 581           pvs->is_postprocessing_view = false;
 582
 583           continue;
 584         }
 585
 586       // In the normal case, this input section is simply mapped to
 587       // the output section at offset OUTPUT_OFFSET.
 588
 589       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
 590       // handled specially--e.g., a .eh_frame section.  The relocation
 591       // routines need to check for each reloc where it should be
 592       // applied.  For this case, we need an input/output view for the
 593       // entire contents of the section in the output file.  We don't
 594       // want to copy the contents of the input section to the output
 595       // section; the output section contents were already written,
 596       // and we waited for them in Relocate_task::is_runnable because
 597       // relocs_must_follow_section_writes is set for the object.
 598
 599       // Regardless of which of the above cases is true, we have to
 600       // check requires_postprocessing of the output section.  If that
 601       // is false, then we work with views of the output file
 602       // directly.  If it is true, then we work with a separate
 603       // buffer, and the output section is responsible for writing the
 604       // final data to the output file.
 605
 606       off_t output_section_offset;
 607       Address output_section_size;
 608       if (!os->requires_postprocessing())
 609         {
 610           output_section_offset = os->offset();
 611           output_section_size = convert_types<Address, off_t>(os->data_size());
 612         }
 613       else
 614         {
 615           output_section_offset = 0;
 616           output_section_size =
 617               convert_types<Address, off_t>(os->postprocessing_buffer_size());
 618         }
 619
 620       off_t view_start;
 621       section_size_type view_size;
 622       if (output_offset != invalid_address)
 623         {
 624           view_start = output_section_offset + output_offset;
 625           view_size = convert_to_section_size_type(shdr.get_sh_size());
 626         }
 627       else
 628         {
 629           view_start = output_section_offset;
 630           view_size = convert_to_section_size_type(output_section_size);
 631         }
 632
 633       if (view_size == 0)
 634         continue;
 635
 636       gold_assert(output_offset == invalid_address
 637                   || output_offset + view_size <= output_section_size);
 638
 639       unsigned char* view;
 640       if (os->requires_postprocessing())
 641         {
 642           unsigned char* buffer = os->postprocessing_buffer();
 643           view = buffer + view_start;
 644           if (output_offset != invalid_address)
 645             {
 646               off_t sh_offset = shdr.get_sh_offset();
 647               if (!rm.empty() && rm.back().file_offset > sh_offset)
 648                 is_sorted = false;
 649               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 650                                                           view_size, view));
 651             }
 652         }
 653       else
 654         {
 655           if (output_offset == invalid_address)
 656             view = of->get_input_output_view(view_start, view_size);
 657           else
 658             {
 659               view = of->get_output_view(view_start, view_size);
 660               off_t sh_offset = shdr.get_sh_offset();
 661               if (!rm.empty() && rm.back().file_offset > sh_offset)
 662                 is_sorted = false;
 663               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 664                                                           view_size, view));
 665             }
 666         }
 667
 668       pvs->view = view;
 669       pvs->address = os->address();
 670       if (output_offset != invalid_address)
 671         pvs->address += output_offset;
 672       pvs->offset = view_start;
 673       pvs->view_size = view_size;
 674       pvs->is_input_output_view = output_offset == invalid_address;
 675       pvs->is_postprocessing_view = os->requires_postprocessing();
 676     }
 677
 678   // Actually read the data.
 679   if (!rm.empty())
 680     {
 681       if (!is_sorted)
 682         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
 683       this->read_multiple(rm);
 684     }
 685 }
 686
 687 // Relocate section data.  VIEWS points to the section data as views
 688 // in the output file.
 689
 690 template<int size, bool big_endian>
 691 void
 692 Sized_relobj<size, big_endian>::relocate_sections(
 693     const General_options& options,
 694     const Symbol_table* symtab,
 695     const Layout* layout,
 696     const unsigned char* pshdrs,
 697     Views* pviews)
 698 {
 699   unsigned int shnum = this->shnum();
 700   Sized_target<size, big_endian>* target = this->sized_target();
 701
 702   const Output_sections& out_sections(this->output_sections());
 703   const std::vector<Address>& out_offsets(this->section_offsets_);
 704
 705   Relocate_info<size, big_endian> relinfo;
 706   relinfo.options = &options;
 707   relinfo.symtab = symtab;
 708   relinfo.layout = layout;
 709   relinfo.object = this;
 710
 711   const unsigned char* p = pshdrs + This::shdr_size;
 712   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 713     {
 714       typename This::Shdr shdr(p);
 715
 716       unsigned int sh_type = shdr.get_sh_type();
 717       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 718         continue;
 719
 720       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
 721       if (index >= this->shnum())
 722         {
 723           this->error(_("relocation section %u has bad info %u"),
 724                       i, index);
 725           continue;
 726         }
 727
 728       Output_section* os = out_sections[index];
 729       if (os == NULL)
 730         {
 731           // This relocation section is against a section which we
 732           // discarded.
 733           continue;
 734         }
 735       Address output_offset = out_offsets[index];
 736
 737       gold_assert((*pviews)[index].view != NULL);
 738       if (parameters->options().relocatable())
 739         gold_assert((*pviews)[i].view != NULL);
 740
 741       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 742         {
 743           gold_error(_("relocation section %u uses unexpected "
 744                        "symbol table %u"),
 745                      i, this->adjust_shndx(shdr.get_sh_link()));
 746           continue;
 747         }
 748
 749       off_t sh_size = shdr.get_sh_size();
 750       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
 751                                                     sh_size, true, false);
 752
 753       unsigned int reloc_size;
 754       if (sh_type == elfcpp::SHT_REL)
 755         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 756       else
 757         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 758
 759       if (reloc_size != shdr.get_sh_entsize())
 760         {
 761           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
 762                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 763                      reloc_size);
 764           continue;
 765         }
 766
 767       size_t reloc_count = sh_size / reloc_size;
 768       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 769         {
 770           gold_error(_("reloc section %u size %lu uneven"),
 771                      i, static_cast<unsigned long>(sh_size));
 772           continue;
 773         }
 774
 775       gold_assert(output_offset != invalid_address
 776                   || this->relocs_must_follow_section_writes());
 777
 778       relinfo.reloc_shndx = i;
 779       relinfo.data_shndx = index;
 780       if (!parameters->options().relocatable())
 781         {
 782           target->relocate_section(&relinfo,
 783                                    sh_type,
 784                                    prelocs,
 785                                    reloc_count,
 786                                    os,
 787                                    output_offset == invalid_address,
 788                                    (*pviews)[index].view,
 789                                    (*pviews)[index].address,
 790                                    (*pviews)[index].view_size);
 791           if (parameters->options().emit_relocs())
 792             this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
 793                               os, output_offset,
 794                               (*pviews)[index].view,
 795                               (*pviews)[index].address,
 796                               (*pviews)[index].view_size,
 797                               (*pviews)[i].view,
 798                               (*pviews)[i].view_size);
 799         }
 800       else
 801         {
 802           Relocatable_relocs* rr = this->relocatable_relocs(i);
 803           target->relocate_for_relocatable(&relinfo,
 804                                            sh_type,
 805                                            prelocs,
 806                                            reloc_count,
 807                                            os,
 808                                            output_offset,
 809                                            rr,
 810                                            (*pviews)[index].view,
 811                                            (*pviews)[index].address,
 812                                            (*pviews)[index].view_size,
 813                                            (*pviews)[i].view,
 814                                            (*pviews)[i].view_size);
 815         }
 816     }
 817 }
 818
 819 // Emit the relocs for --emit-relocs.
 820
 821 template<int size, bool big_endian>
 822 void
 823 Sized_relobj<size, big_endian>::emit_relocs(
 824     const Relocate_info<size, big_endian>* relinfo,
 825     unsigned int i,
 826     unsigned int sh_type,
 827     const unsigned char* prelocs,
 828     size_t reloc_count,
 829     Output_section* output_section,
 830     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 831     unsigned char* view,
 832     typename elfcpp::Elf_types<size>::Elf_Addr address,
 833     section_size_type view_size,
 834     unsigned char* reloc_view,
 835     section_size_type reloc_view_size)
 836 {
 837   if (sh_type == elfcpp::SHT_REL)
 838     this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
 839                                                reloc_count, output_section,
 840                                                offset_in_output_section,
 841                                                view, address, view_size,
 842                                                reloc_view, reloc_view_size);
 843   else
 844     {
 845       gold_assert(sh_type == elfcpp::SHT_RELA);
 846       this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
 847                                                   reloc_count, output_section,
 848                                                   offset_in_output_section,
 849                                                   view, address, view_size,
 850                                                   reloc_view, reloc_view_size);
 851     }
 852 }
 853
 854 // Emit the relocs for --emit-relocs, templatized on the type of the
 855 // relocation section.
 856
 857 template<int size, bool big_endian>
 858 template<int sh_type>
 859 void
 860 Sized_relobj<size, big_endian>::emit_relocs_reltype(
 861     const Relocate_info<size, big_endian>* relinfo,
 862     unsigned int i,
 863     const unsigned char* prelocs,
 864     size_t reloc_count,
 865     Output_section* output_section,
 866     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 867     unsigned char* view,
 868     typename elfcpp::Elf_types<size>::Elf_Addr address,
 869     section_size_type view_size,
 870     unsigned char* reloc_view,
 871     section_size_type reloc_view_size)
 872 {
 873   const Relocatable_relocs* rr = this->relocatable_relocs(i);
 874   relocate_for_relocatable<size, big_endian, sh_type>(
 875     relinfo,
 876     prelocs,
 877     reloc_count,
 878     output_section,
 879     offset_in_output_section,
 880     rr,
 881     view,
 882     address,
 883     view_size,
 884     reloc_view,
 885     reloc_view_size);
 886 }
 887
 888 // Create merge hash tables for the local symbols.  These are used to
 889 // speed up relocations.
 890
 891 template<int size, bool big_endian>
 892 void
 893 Sized_relobj<size, big_endian>::initialize_input_to_output_maps()
 894 {
 895   const unsigned int loccount = this->local_symbol_count_;
 896   for (unsigned int i = 1; i < loccount; ++i)
 897     {
 898       Symbol_value<size>& lv(this->local_values_[i]);
 899       lv.initialize_input_to_output_map(this);
 900     }
 901 }
 902
 903 // Free merge hash tables for the local symbols.
 904
 905 template<int size, bool big_endian>
 906 void
 907 Sized_relobj<size, big_endian>::free_input_to_output_maps()
 908 {
 909   const unsigned int loccount = this->local_symbol_count_;
 910   for (unsigned int i = 1; i < loccount; ++i)
 911     {
 912       Symbol_value<size>& lv(this->local_values_[i]);
 913       lv.free_input_to_output_map();
 914     }
 915 }
 916
 917 // Class Merged_symbol_value.
 918
 919 template<int size>
 920 void
 921 Merged_symbol_value<size>::initialize_input_to_output_map(
 922     const Relobj* object,
 923     unsigned int input_shndx)
 924 {
 925   Object_merge_map* map = object->merge_map();
 926   map->initialize_input_to_output_map<size>(input_shndx,
 927                                             this->output_start_address_,
 928                                             &this->output_addresses_);
 929 }
 930
 931 // Get the output value corresponding to an input offset if we
 932 // couldn't find it in the hash table.
 933
 934 template<int size>
 935 typename elfcpp::Elf_types<size>::Elf_Addr
 936 Merged_symbol_value<size>::value_from_output_section(
 937     const Relobj* object,
 938     unsigned int input_shndx,
 939     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
 940 {
 941   section_offset_type output_offset;
 942   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
 943                                                       input_offset,
 944                                                       &output_offset);
 945
 946   // If this assertion fails, it means that some relocation was
 947   // against a portion of an input merge section which we didn't map
 948   // to the output file and we didn't explicitly discard.  We should
 949   // always map all portions of input merge sections.
 950   gold_assert(found);
 951
 952   if (output_offset == -1)
 953     return 0;
 954   else
 955     return this->output_start_address_ + output_offset;
 956 }
 957
 958 // Track_relocs methods.
 959
 960 // Initialize the class to track the relocs.  This gets the object,
 961 // the reloc section index, and the type of the relocs.  This returns
 962 // false if something goes wrong.
 963
 964 template<int size, bool big_endian>
 965 bool
 966 Track_relocs<size, big_endian>::initialize(
 967     Object* object,
 968     unsigned int reloc_shndx,
 969     unsigned int reloc_type)
 970 {
 971   // If RELOC_SHNDX is -1U, it means there is more than one reloc
 972   // section for the .eh_frame section.  We can't handle that case.
 973   if (reloc_shndx == -1U)
 974     return false;
 975
 976   // If RELOC_SHNDX is 0, there is no reloc section.
 977   if (reloc_shndx == 0)
 978     return true;
 979
 980   // Get the contents of the reloc section.
 981   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
 982
 983   if (reloc_type == elfcpp::SHT_REL)
 984     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
 985   else if (reloc_type == elfcpp::SHT_RELA)
 986     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
 987   else
 988     gold_unreachable();
 989
 990   if (this->len_ % this->reloc_size_ != 0)
 991     {
 992       object->error(_("reloc section size %zu is not a multiple of "
 993                       "reloc size %d\n"),
 994                     static_cast<size_t>(this->len_),
 995                     this->reloc_size_);
 996       return false;
 997     }
 998
 999   return true;
1000 }
1001
1002 // Return the offset of the next reloc, or -1 if there isn't one.
1003
1004 template<int size, bool big_endian>
1005 off_t
1006 Track_relocs<size, big_endian>::next_offset() const
1007 {
1008   if (this->pos_ >= this->len_)
1009     return -1;
1010
1011   // Rel and Rela start out the same, so we can always use Rel to find
1012   // the r_offset value.
1013   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1014   return rel.get_r_offset();
1015 }
1016
1017 // Return the index of the symbol referenced by the next reloc, or -1U
1018 // if there aren't any more relocs.
1019
1020 template<int size, bool big_endian>
1021 unsigned int
1022 Track_relocs<size, big_endian>::next_symndx() const
1023 {
1024   if (this->pos_ >= this->len_)
1025     return -1U;
1026
1027   // Rel and Rela start out the same, so we can use Rel to find the
1028   // symbol index.
1029   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1030   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1031 }
1032
1033 // Advance to the next reloc whose r_offset is greater than or equal
1034 // to OFFSET.  Return the number of relocs we skip.
1035
1036 template<int size, bool big_endian>
1037 int
1038 Track_relocs<size, big_endian>::advance(off_t offset)
1039 {
1040   int ret = 0;
1041   while (this->pos_ < this->len_)
1042     {
1043       // Rel and Rela start out the same, so we can always use Rel to
1044       // find the r_offset value.
1045       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1046       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1047         break;
1048       ++ret;
1049       this->pos_ += this->reloc_size_;
1050     }
1051   return ret;
1052 }
1053
1054 // Instantiate the templates we need.
1055
1056 #ifdef HAVE_TARGET_32_LITTLE
1057 template
1058 void
1059 Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
1060 #endif
1061
1062 #ifdef HAVE_TARGET_32_BIG
1063 template
1064 void
1065 Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
1066 #endif
1067
1068 #ifdef HAVE_TARGET_64_LITTLE
1069 template
1070 void
1071 Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
1072 #endif
1073
1074 #ifdef HAVE_TARGET_64_BIG
1075 template
1076 void
1077 Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
1078 #endif
1079
1080 #ifdef HAVE_TARGET_32_LITTLE
1081 template
1082 void
1083 Sized_relobj<32, false>::do_scan_relocs(const General_options& options,
1084                                         Symbol_table* symtab,
1085                                         Layout* layout,
1086                                         Read_relocs_data* rd);
1087 #endif
1088
1089 #ifdef HAVE_TARGET_32_BIG
1090 template
1091 void
1092 Sized_relobj<32, true>::do_scan_relocs(const General_options& options,
1093                                        Symbol_table* symtab,
1094                                        Layout* layout,
1095                                        Read_relocs_data* rd);
1096 #endif
1097
1098 #ifdef HAVE_TARGET_64_LITTLE
1099 template
1100 void
1101 Sized_relobj<64, false>::do_scan_relocs(const General_options& options,
1102                                         Symbol_table* symtab,
1103                                         Layout* layout,
1104                                         Read_relocs_data* rd);
1105 #endif
1106
1107 #ifdef HAVE_TARGET_64_BIG
1108 template
1109 void
1110 Sized_relobj<64, true>::do_scan_relocs(const General_options& options,
1111                                        Symbol_table* symtab,
1112                                        Layout* layout,
1113                                        Read_relocs_data* rd);
1114 #endif
1115
1116 #ifdef HAVE_TARGET_32_LITTLE
1117 template
1118 void
1119 Sized_relobj<32, false>::do_relocate(const General_options& options,
1120                                      const Symbol_table* symtab,
1121                                      const Layout* layout,
1122                                      Output_file* of);
1123 #endif
1124
1125 #ifdef HAVE_TARGET_32_BIG
1126 template
1127 void
1128 Sized_relobj<32, true>::do_relocate(const General_options& options,
1129                                     const Symbol_table* symtab,
1130                                     const Layout* layout,
1131                                     Output_file* of);
1132 #endif
1133
1134 #ifdef HAVE_TARGET_64_LITTLE
1135 template
1136 void
1137 Sized_relobj<64, false>::do_relocate(const General_options& options,
1138                                      const Symbol_table* symtab,
1139                                      const Layout* layout,
1140                                      Output_file* of);
1141 #endif
1142
1143 #ifdef HAVE_TARGET_64_BIG
1144 template
1145 void
1146 Sized_relobj<64, true>::do_relocate(const General_options& options,
1147                                     const Symbol_table* symtab,
1148                                     const Layout* layout,
1149                                     Output_file* of);
1150 #endif
1151
1152 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1153 template
1154 class Merged_symbol_value<32>;
1155 #endif
1156
1157 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1158 template
1159 class Merged_symbol_value<64>;
1160 #endif
1161
1162 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1163 template
1164 class Symbol_value<32>;
1165 #endif
1166
1167 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1168 template
1169 class Symbol_value<64>;
1170 #endif
1171
1172 #ifdef HAVE_TARGET_32_LITTLE
1173 template
1174 class Track_relocs<32, false>;
1175 #endif
1176
1177 #ifdef HAVE_TARGET_32_BIG
1178 template
1179 class Track_relocs<32, true>;
1180 #endif
1181
1182 #ifdef HAVE_TARGET_64_LITTLE
1183 template
1184 class Track_relocs<64, false>;
1185 #endif
1186
1187 #ifdef HAVE_TARGET_64_BIG
1188 template
1189 class Track_relocs<64, true>;
1190 #endif
1191
1192 } // End namespace gold.