gold/reloc.cc

   1 // reloc.cc -- relocate input files for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <algorithm>
  26
  27 #include "workqueue.h"
  28 #include "layout.h"
  29 #include "symtab.h"
  30 #include "output.h"
  31 #include "merge.h"
  32 #include "object.h"
  33 #include "target-reloc.h"
  34 #include "reloc.h"
  35 #include "icf.h"
  36 #include "compressed_output.h"
  37 #include "incremental.h"
  38
  39 namespace gold
  40 {
  41
  42 // Read_relocs methods.
  43
  44 // These tasks just read the relocation information from the file.
  45 // After reading it, the start another task to process the
  46 // information.  These tasks requires access to the file.
  47
  48 Task_token*
  49 Read_relocs::is_runnable()
  50 {
  51   return this->object_->is_locked() ? this->object_->token() : NULL;
  52 }
  53
  54 // Lock the file.
  55
  56 void
  57 Read_relocs::locks(Task_locker* tl)
  58 {
  59   tl->add(this, this->object_->token());
  60 }
  61
  62 // Read the relocations and then start a Scan_relocs_task.
  63
  64 void
  65 Read_relocs::run(Workqueue* workqueue)
  66 {
  67   Read_relocs_data* rd = new Read_relocs_data;
  68   this->object_->read_relocs(rd);
  69   this->object_->set_relocs_data(rd);
  70   this->object_->release();
  71
  72   // If garbage collection or identical comdat folding is desired, we
  73   // process the relocs first before scanning them.  Scanning of relocs is
  74   // done only after garbage or identical sections is identified.
  75   if (parameters->options().gc_sections()
  76       || parameters->options().icf_enabled())
  77     {
  78       workqueue->queue_next(new Gc_process_relocs(this->symtab_,
  79                                                   this->layout_,
  80                                                   this->object_, rd,
  81                                                   this->this_blocker_,
  82                                                   this->next_blocker_));
  83     }
  84   else
  85     {
  86       workqueue->queue_next(new Scan_relocs(this->symtab_, this->layout_,
  87                                             this->object_, rd,
  88                                             this->this_blocker_,
  89                                             this->next_blocker_));
  90     }
  91 }
  92
  93 // Return a debugging name for the task.
  94
  95 std::string
  96 Read_relocs::get_name() const
  97 {
  98   return "Read_relocs " + this->object_->name();
  99 }
 100
 101 // Gc_process_relocs methods.
 102
 103 Gc_process_relocs::~Gc_process_relocs()
 104 {
 105   if (this->this_blocker_ != NULL)
 106     delete this->this_blocker_;
 107 }
 108
 109 // These tasks process the relocations read by Read_relocs and
 110 // determine which sections are referenced and which are garbage.
 111 // This task is done only when --gc-sections is used.  This is blocked
 112 // by THIS_BLOCKER_.  It unblocks NEXT_BLOCKER_.
 113
 114 Task_token*
 115 Gc_process_relocs::is_runnable()
 116 {
 117   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 118     return this->this_blocker_;
 119   if (this->object_->is_locked())
 120     return this->object_->token();
 121   return NULL;
 122 }
 123
 124 void
 125 Gc_process_relocs::locks(Task_locker* tl)
 126 {
 127   tl->add(this, this->object_->token());
 128   tl->add(this, this->next_blocker_);
 129 }
 130
 131 void
 132 Gc_process_relocs::run(Workqueue*)
 133 {
 134   this->object_->gc_process_relocs(this->symtab_, this->layout_, this->rd_);
 135   this->object_->release();
 136 }
 137
 138 // Return a debugging name for the task.
 139
 140 std::string
 141 Gc_process_relocs::get_name() const
 142 {
 143   return "Gc_process_relocs " + this->object_->name();
 144 }
 145
 146 // Scan_relocs methods.
 147
 148 Scan_relocs::~Scan_relocs()
 149 {
 150   if (this->this_blocker_ != NULL)
 151     delete this->this_blocker_;
 152 }
 153
 154 // These tasks scan the relocations read by Read_relocs and mark up
 155 // the symbol table to indicate which relocations are required.  We
 156 // use a lock on the symbol table to keep them from interfering with
 157 // each other.
 158
 159 Task_token*
 160 Scan_relocs::is_runnable()
 161 {
 162   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 163     return this->this_blocker_;
 164   if (this->object_->is_locked())
 165     return this->object_->token();
 166   return NULL;
 167 }
 168
 169 // Return the locks we hold: one on the file, one on the symbol table
 170 // and one blocker.
 171
 172 void
 173 Scan_relocs::locks(Task_locker* tl)
 174 {
 175   tl->add(this, this->object_->token());
 176   tl->add(this, this->next_blocker_);
 177 }
 178
 179 // Scan the relocs.
 180
 181 void
 182 Scan_relocs::run(Workqueue*)
 183 {
 184   this->object_->scan_relocs(this->symtab_, this->layout_, this->rd_);
 185   delete this->rd_;
 186   this->rd_ = NULL;
 187   this->object_->release();
 188 }
 189
 190 // Return a debugging name for the task.
 191
 192 std::string
 193 Scan_relocs::get_name() const
 194 {
 195   return "Scan_relocs " + this->object_->name();
 196 }
 197
 198 // Relocate_task methods.
 199
 200 // We may have to wait for the output sections to be written.
 201
 202 Task_token*
 203 Relocate_task::is_runnable()
 204 {
 205   if (this->object_->relocs_must_follow_section_writes()
 206       && this->output_sections_blocker_->is_blocked())
 207     return this->output_sections_blocker_;
 208
 209   if (this->object_->is_locked())
 210     return this->object_->token();
 211
 212   return NULL;
 213 }
 214
 215 // We want to lock the file while we run.  We want to unblock
 216 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
 217 // INPUT_SECTIONS_BLOCKER may be NULL.
 218
 219 void
 220 Relocate_task::locks(Task_locker* tl)
 221 {
 222   if (this->input_sections_blocker_ != NULL)
 223     tl->add(this, this->input_sections_blocker_);
 224   tl->add(this, this->final_blocker_);
 225   tl->add(this, this->object_->token());
 226 }
 227
 228 // Run the task.
 229
 230 void
 231 Relocate_task::run(Workqueue*)
 232 {
 233   this->object_->relocate(this->symtab_, this->layout_, this->of_);
 234
 235   // This is normally the last thing we will do with an object, so
 236   // uncache all views.
 237   this->object_->clear_view_cache_marks();
 238
 239   this->object_->release();
 240 }
 241
 242 // Return a debugging name for the task.
 243
 244 std::string
 245 Relocate_task::get_name() const
 246 {
 247   return "Relocate_task " + this->object_->name();
 248 }
 249
 250 // Read the relocs and local symbols from the object file and store
 251 // the information in RD.
 252
 253 template<int size, bool big_endian>
 254 void
 255 Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
 256 {
 257   rd->relocs.clear();
 258
 259   unsigned int shnum = this->shnum();
 260   if (shnum == 0)
 261     return;
 262
 263   rd->relocs.reserve(shnum / 2);
 264
 265   const Output_sections& out_sections(this->output_sections());
 266   const std::vector<Address>& out_offsets(this->section_offsets_);
 267
 268   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 269                                                shnum * This::shdr_size,
 270                                                true, true);
 271   // Skip the first, dummy, section.
 272   const unsigned char* ps = pshdrs + This::shdr_size;
 273   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
 274     {
 275       typename This::Shdr shdr(ps);
 276
 277       unsigned int sh_type = shdr.get_sh_type();
 278       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 279         continue;
 280
 281       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
 282       if (shndx >= shnum)
 283         {
 284           this->error(_("relocation section %u has bad info %u"),
 285                       i, shndx);
 286           continue;
 287         }
 288
 289       Output_section* os = out_sections[shndx];
 290       if (os == NULL)
 291         continue;
 292
 293       // We are scanning relocations in order to fill out the GOT and
 294       // PLT sections.  Relocations for sections which are not
 295       // allocated (typically debugging sections) should not add new
 296       // GOT and PLT entries.  So we skip them unless this is a
 297       // relocatable link or we need to emit relocations.  FIXME: What
 298       // should we do if a linker script maps a section with SHF_ALLOC
 299       // clear to a section with SHF_ALLOC set?
 300       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
 301       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
 302                                    != 0);
 303       if (!is_section_allocated
 304           && !parameters->options().relocatable()
 305           && !parameters->options().emit_relocs()
 306           && !parameters->incremental())
 307         continue;
 308
 309       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 310         {
 311           this->error(_("relocation section %u uses unexpected "
 312                         "symbol table %u"),
 313                       i, this->adjust_shndx(shdr.get_sh_link()));
 314           continue;
 315         }
 316
 317       off_t sh_size = shdr.get_sh_size();
 318
 319       unsigned int reloc_size;
 320       if (sh_type == elfcpp::SHT_REL)
 321         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 322       else
 323         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 324       if (reloc_size != shdr.get_sh_entsize())
 325         {
 326           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
 327                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 328                       reloc_size);
 329           continue;
 330         }
 331
 332       size_t reloc_count = sh_size / reloc_size;
 333       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 334         {
 335           this->error(_("reloc section %u size %lu uneven"),
 336                       i, static_cast<unsigned long>(sh_size));
 337           continue;
 338         }
 339
 340       rd->relocs.push_back(Section_relocs());
 341       Section_relocs& sr(rd->relocs.back());
 342       sr.reloc_shndx = i;
 343       sr.data_shndx = shndx;
 344       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
 345                                            true, true);
 346       sr.sh_type = sh_type;
 347       sr.reloc_count = reloc_count;
 348       sr.output_section = os;
 349       sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
 350       sr.is_data_section_allocated = is_section_allocated;
 351     }
 352
 353   // Read the local symbols.
 354   gold_assert(this->symtab_shndx_ != -1U);
 355   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
 356     rd->local_symbols = NULL;
 357   else
 358     {
 359       typename This::Shdr symtabshdr(pshdrs
 360                                      + this->symtab_shndx_ * This::shdr_size);
 361       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
 362       const int sym_size = This::sym_size;
 363       const unsigned int loccount = this->local_symbol_count_;
 364       gold_assert(loccount == symtabshdr.get_sh_info());
 365       off_t locsize = loccount * sym_size;
 366       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
 367                                                  locsize, true, true);
 368     }
 369 }
 370
 371 // Process the relocs to generate mappings from source sections to referenced
 372 // sections.  This is used during garbage collection to determine garbage
 373 // sections.
 374
 375 template<int size, bool big_endian>
 376 void
 377 Sized_relobj<size, big_endian>::do_gc_process_relocs(Symbol_table* symtab,
 378                                                      Layout* layout,
 379                                                      Read_relocs_data* rd)
 380 {
 381   Sized_target<size, big_endian>* target =
 382     parameters->sized_target<size, big_endian>();
 383
 384   const unsigned char* local_symbols;
 385   if (rd->local_symbols == NULL)
 386     local_symbols = NULL;
 387   else
 388     local_symbols = rd->local_symbols->data();
 389
 390   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 391        p != rd->relocs.end();
 392        ++p)
 393     {
 394       if (!parameters->options().relocatable())
 395           {
 396             // As noted above, when not generating an object file, we
 397             // only scan allocated sections.  We may see a non-allocated
 398             // section here if we are emitting relocs.
 399             if (p->is_data_section_allocated)
 400               target->gc_process_relocs(symtab, layout, this,
 401                                         p->data_shndx, p->sh_type,
 402                                         p->contents->data(), p->reloc_count,
 403                                         p->output_section,
 404                                         p->needs_special_offset_handling,
 405                                         this->local_symbol_count_,
 406                                         local_symbols);
 407         }
 408     }
 409 }
 410
 411
 412 // Scan the relocs and adjust the symbol table.  This looks for
 413 // relocations which require GOT/PLT/COPY relocations.
 414
 415 template<int size, bool big_endian>
 416 void
 417 Sized_relobj<size, big_endian>::do_scan_relocs(Symbol_table* symtab,
 418                                                Layout* layout,
 419                                                Read_relocs_data* rd)
 420 {
 421   Sized_target<size, big_endian>* target =
 422     parameters->sized_target<size, big_endian>();
 423
 424   const unsigned char* local_symbols;
 425   if (rd->local_symbols == NULL)
 426     local_symbols = NULL;
 427   else
 428     local_symbols = rd->local_symbols->data();
 429
 430   // For incremental links, allocate the counters for incremental relocations.
 431   if (layout->incremental_inputs() != NULL)
 432     this->allocate_incremental_reloc_counts();
 433
 434   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 435        p != rd->relocs.end();
 436        ++p)
 437     {
 438       // When garbage collection is on, unreferenced sections are not included
 439       // in the link that would have been included normally. This is known only
 440       // after Read_relocs hence this check has to be done again.
 441       if (parameters->options().gc_sections()
 442           || parameters->options().icf_enabled())
 443         {
 444           if (p->output_section == NULL)
 445             continue;
 446         }
 447       if (!parameters->options().relocatable())
 448         {
 449           // As noted above, when not generating an object file, we
 450           // only scan allocated sections.  We may see a non-allocated
 451           // section here if we are emitting relocs.
 452           if (p->is_data_section_allocated)
 453             target->scan_relocs(symtab, layout, this, p->data_shndx,
 454                                 p->sh_type, p->contents->data(),
 455                                 p->reloc_count, p->output_section,
 456                                 p->needs_special_offset_handling,
 457                                 this->local_symbol_count_,
 458                                 local_symbols);
 459           if (parameters->options().emit_relocs())
 460             this->emit_relocs_scan(symtab, layout, local_symbols, p);
 461           if (layout->incremental_inputs() != NULL)
 462             this->incremental_relocs_scan(p);
 463         }
 464       else
 465         {
 466           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 467           gold_assert(rr != NULL);
 468           rr->set_reloc_count(p->reloc_count);
 469           target->scan_relocatable_relocs(symtab, layout, this,
 470                                           p->data_shndx, p->sh_type,
 471                                           p->contents->data(),
 472                                           p->reloc_count,
 473                                           p->output_section,
 474                                           p->needs_special_offset_handling,
 475                                           this->local_symbol_count_,
 476                                           local_symbols,
 477                                           rr);
 478         }
 479
 480       delete p->contents;
 481       p->contents = NULL;
 482     }
 483
 484   // For incremental links, finalize the allocation of relocations.
 485   if (layout->incremental_inputs() != NULL)
 486     this->finalize_incremental_relocs(layout);
 487
 488   if (rd->local_symbols != NULL)
 489     {
 490       delete rd->local_symbols;
 491       rd->local_symbols = NULL;
 492     }
 493 }
 494
 495 // This is a strategy class we use when scanning for --emit-relocs.
 496
 497 template<int sh_type>
 498 class Emit_relocs_strategy
 499 {
 500  public:
 501   // A local non-section symbol.
 502   inline Relocatable_relocs::Reloc_strategy
 503   local_non_section_strategy(unsigned int, Relobj*, unsigned int)
 504   { return Relocatable_relocs::RELOC_COPY; }
 505
 506   // A local section symbol.
 507   inline Relocatable_relocs::Reloc_strategy
 508   local_section_strategy(unsigned int, Relobj*)
 509   {
 510     if (sh_type == elfcpp::SHT_RELA)
 511       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 512     else
 513       {
 514         // The addend is stored in the section contents.  Since this
 515         // is not a relocatable link, we are going to apply the
 516         // relocation contents to the section as usual.  This means
 517         // that we have no way to record the original addend.  If the
 518         // original addend is not zero, there is basically no way for
 519         // the user to handle this correctly.  Caveat emptor.
 520         return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 521       }
 522   }
 523
 524   // A global symbol.
 525   inline Relocatable_relocs::Reloc_strategy
 526   global_strategy(unsigned int, Relobj*, unsigned int)
 527   { return Relocatable_relocs::RELOC_COPY; }
 528 };
 529
 530 // Scan the input relocations for --emit-relocs.
 531
 532 template<int size, bool big_endian>
 533 void
 534 Sized_relobj<size, big_endian>::emit_relocs_scan(
 535     Symbol_table* symtab,
 536     Layout* layout,
 537     const unsigned char* plocal_syms,
 538     const Read_relocs_data::Relocs_list::iterator& p)
 539 {
 540   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 541   gold_assert(rr != NULL);
 542   rr->set_reloc_count(p->reloc_count);
 543
 544   if (p->sh_type == elfcpp::SHT_REL)
 545     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(symtab, layout,
 546                                                     plocal_syms, p, rr);
 547   else
 548     {
 549       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 550       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(symtab, layout,
 551                                                        plocal_syms, p, rr);
 552     }
 553 }
 554
 555 // Scan the input relocation for --emit-relocs, templatized on the
 556 // type of the relocation section.
 557
 558 template<int size, bool big_endian>
 559 template<int sh_type>
 560 void
 561 Sized_relobj<size, big_endian>::emit_relocs_scan_reltype(
 562     Symbol_table* symtab,
 563     Layout* layout,
 564     const unsigned char* plocal_syms,
 565     const Read_relocs_data::Relocs_list::iterator& p,
 566     Relocatable_relocs* rr)
 567 {
 568   scan_relocatable_relocs<size, big_endian, sh_type,
 569                           Emit_relocs_strategy<sh_type> >(
 570     symtab,
 571     layout,
 572     this,
 573     p->data_shndx,
 574     p->contents->data(),
 575     p->reloc_count,
 576     p->output_section,
 577     p->needs_special_offset_handling,
 578     this->local_symbol_count_,
 579     plocal_syms,
 580     rr);
 581 }
 582
 583 // Scan the input relocations for --incremental.
 584
 585 template<int size, bool big_endian>
 586 void
 587 Sized_relobj<size, big_endian>::incremental_relocs_scan(
 588     const Read_relocs_data::Relocs_list::iterator& p)
 589 {
 590   if (p->sh_type == elfcpp::SHT_REL)
 591     this->incremental_relocs_scan_reltype<elfcpp::SHT_REL>(p);
 592   else
 593     {
 594       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 595       this->incremental_relocs_scan_reltype<elfcpp::SHT_RELA>(p);
 596     }
 597 }
 598
 599 // Scan the input relocation for --emit-relocs, templatized on the
 600 // type of the relocation section.
 601
 602 template<int size, bool big_endian>
 603 template<int sh_type>
 604 void
 605 Sized_relobj<size, big_endian>::incremental_relocs_scan_reltype(
 606     const Read_relocs_data::Relocs_list::iterator& p)
 607 {
 608   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 609   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 610   const unsigned char* prelocs = p->contents->data();
 611   size_t reloc_count = p->reloc_count;
 612
 613   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 614     {
 615       Reltype reloc(prelocs);
 616
 617       if (p->needs_special_offset_handling
 618           && !p->output_section->is_input_address_mapped(this, p->data_shndx,
 619                                                          reloc.get_r_offset()))
 620         continue;
 621
 622       typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 623           reloc.get_r_info();
 624       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 625
 626       if (r_sym >= this->local_symbol_count_)
 627         this->count_incremental_reloc(r_sym - this->local_symbol_count_);
 628     }
 629 }
 630
 631 // Relocate the input sections and write out the local symbols.
 632
 633 template<int size, bool big_endian>
 634 void
 635 Sized_relobj<size, big_endian>::do_relocate(const Symbol_table* symtab,
 636                                             const Layout* layout,
 637                                             Output_file* of)
 638 {
 639   unsigned int shnum = this->shnum();
 640
 641   // Read the section headers.
 642   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 643                                                shnum * This::shdr_size,
 644                                                true, true);
 645
 646   Views views;
 647   views.resize(shnum);
 648
 649   // Make two passes over the sections.  The first one copies the
 650   // section data to the output file.  The second one applies
 651   // relocations.
 652
 653   this->write_sections(pshdrs, of, &views);
 654
 655   // To speed up relocations, we set up hash tables for fast lookup of
 656   // input offsets to output addresses.
 657   this->initialize_input_to_output_maps();
 658
 659   // Apply relocations.
 660
 661   this->relocate_sections(symtab, layout, pshdrs, of, &views);
 662
 663   // After we've done the relocations, we release the hash tables,
 664   // since we no longer need them.
 665   this->free_input_to_output_maps();
 666
 667   // Write out the accumulated views.
 668   for (unsigned int i = 1; i < shnum; ++i)
 669     {
 670       if (views[i].view != NULL)
 671         {
 672           if (!views[i].is_postprocessing_view)
 673             {
 674               if (views[i].is_input_output_view)
 675                 of->write_input_output_view(views[i].offset,
 676                                             views[i].view_size,
 677                                             views[i].view);
 678               else
 679                 of->write_output_view(views[i].offset, views[i].view_size,
 680                                       views[i].view);
 681             }
 682         }
 683     }
 684
 685   // Write out the local symbols.
 686   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
 687                             layout->symtab_xindex(), layout->dynsym_xindex());
 688
 689   // We should no longer need the local symbol values.
 690   this->clear_local_symbols();
 691 }
 692
 693 // Sort a Read_multiple vector by file offset.
 694 struct Read_multiple_compare
 695 {
 696   inline bool
 697   operator()(const File_read::Read_multiple_entry& rme1,
 698              const File_read::Read_multiple_entry& rme2) const
 699   { return rme1.file_offset < rme2.file_offset; }
 700 };
 701
 702 // Write section data to the output file.  PSHDRS points to the
 703 // section headers.  Record the views in *PVIEWS for use when
 704 // relocating.
 705
 706 template<int size, bool big_endian>
 707 void
 708 Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
 709                                                Output_file* of,
 710                                                Views* pviews)
 711 {
 712   unsigned int shnum = this->shnum();
 713   const Output_sections& out_sections(this->output_sections());
 714   const std::vector<Address>& out_offsets(this->section_offsets_);
 715
 716   File_read::Read_multiple rm;
 717   bool is_sorted = true;
 718
 719   const unsigned char* p = pshdrs + This::shdr_size;
 720   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 721     {
 722       View_size* pvs = &(*pviews)[i];
 723
 724       pvs->view = NULL;
 725
 726       const Output_section* os = out_sections[i];
 727       if (os == NULL)
 728         continue;
 729       Address output_offset = out_offsets[i];
 730
 731       typename This::Shdr shdr(p);
 732
 733       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
 734         continue;
 735
 736       if ((parameters->options().relocatable()
 737            || parameters->options().emit_relocs())
 738           && (shdr.get_sh_type() == elfcpp::SHT_REL
 739               || shdr.get_sh_type() == elfcpp::SHT_RELA)
 740           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 741         {
 742           // This is a reloc section in a relocatable link or when
 743           // emitting relocs.  We don't need to read the input file.
 744           // The size and file offset are stored in the
 745           // Relocatable_relocs structure.
 746           Relocatable_relocs* rr = this->relocatable_relocs(i);
 747           gold_assert(rr != NULL);
 748           Output_data* posd = rr->output_data();
 749           gold_assert(posd != NULL);
 750
 751           pvs->offset = posd->offset();
 752           pvs->view_size = posd->data_size();
 753           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
 754           pvs->address = posd->address();
 755           pvs->is_input_output_view = false;
 756           pvs->is_postprocessing_view = false;
 757
 758           continue;
 759         }
 760
 761       // In the normal case, this input section is simply mapped to
 762       // the output section at offset OUTPUT_OFFSET.
 763
 764       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
 765       // handled specially--e.g., a .eh_frame section.  The relocation
 766       // routines need to check for each reloc where it should be
 767       // applied.  For this case, we need an input/output view for the
 768       // entire contents of the section in the output file.  We don't
 769       // want to copy the contents of the input section to the output
 770       // section; the output section contents were already written,
 771       // and we waited for them in Relocate_task::is_runnable because
 772       // relocs_must_follow_section_writes is set for the object.
 773
 774       // Regardless of which of the above cases is true, we have to
 775       // check requires_postprocessing of the output section.  If that
 776       // is false, then we work with views of the output file
 777       // directly.  If it is true, then we work with a separate
 778       // buffer, and the output section is responsible for writing the
 779       // final data to the output file.
 780
 781       off_t output_section_offset;
 782       Address output_section_size;
 783       if (!os->requires_postprocessing())
 784         {
 785           output_section_offset = os->offset();
 786           output_section_size = convert_types<Address, off_t>(os->data_size());
 787         }
 788       else
 789         {
 790           output_section_offset = 0;
 791           output_section_size =
 792               convert_types<Address, off_t>(os->postprocessing_buffer_size());
 793         }
 794
 795       off_t view_start;
 796       section_size_type view_size;
 797       bool must_decompress = false;
 798       if (output_offset != invalid_address)
 799         {
 800           view_start = output_section_offset + output_offset;
 801           view_size = convert_to_section_size_type(shdr.get_sh_size());
 802           section_size_type uncompressed_size;
 803           if (this->section_is_compressed(i, &uncompressed_size))
 804             {
 805               view_size = uncompressed_size;
 806               must_decompress = true;
 807             }
 808         }
 809       else
 810         {
 811           view_start = output_section_offset;
 812           view_size = convert_to_section_size_type(output_section_size);
 813         }
 814
 815       if (view_size == 0)
 816         continue;
 817
 818       gold_assert(output_offset == invalid_address
 819                   || output_offset + view_size <= output_section_size);
 820
 821       unsigned char* view;
 822       if (os->requires_postprocessing())
 823         {
 824           unsigned char* buffer = os->postprocessing_buffer();
 825           view = buffer + view_start;
 826           if (output_offset != invalid_address && !must_decompress)
 827             {
 828               off_t sh_offset = shdr.get_sh_offset();
 829               if (!rm.empty() && rm.back().file_offset > sh_offset)
 830                 is_sorted = false;
 831               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 832                                                           view_size, view));
 833             }
 834         }
 835       else
 836         {
 837           if (output_offset == invalid_address)
 838             view = of->get_input_output_view(view_start, view_size);
 839           else
 840             {
 841               view = of->get_output_view(view_start, view_size);
 842               if (!must_decompress)
 843                 {
 844                   off_t sh_offset = shdr.get_sh_offset();
 845                   if (!rm.empty() && rm.back().file_offset > sh_offset)
 846                     is_sorted = false;
 847                   rm.push_back(File_read::Read_multiple_entry(sh_offset,
 848                                                               view_size, view));
 849                 }
 850             }
 851         }
 852
 853       if (must_decompress)
 854         {
 855           // Read and decompress the section.
 856           section_size_type len;
 857           const unsigned char* p = this->section_contents(i, &len, false);
 858           if (!decompress_input_section(p, len, view, view_size))
 859             this->error(_("could not decompress section %s"),
 860                         this->section_name(i).c_str());
 861         }
 862
 863       pvs->view = view;
 864       pvs->address = os->address();
 865       if (output_offset != invalid_address)
 866         pvs->address += output_offset;
 867       pvs->offset = view_start;
 868       pvs->view_size = view_size;
 869       pvs->is_input_output_view = output_offset == invalid_address;
 870       pvs->is_postprocessing_view = os->requires_postprocessing();
 871     }
 872
 873   // Actually read the data.
 874   if (!rm.empty())
 875     {
 876       if (!is_sorted)
 877         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
 878       this->read_multiple(rm);
 879     }
 880 }
 881
 882 // Relocate section data.  VIEWS points to the section data as views
 883 // in the output file.
 884
 885 template<int size, bool big_endian>
 886 void
 887 Sized_relobj<size, big_endian>::do_relocate_sections(
 888     const Symbol_table* symtab,
 889     const Layout* layout,
 890     const unsigned char* pshdrs,
 891     Output_file* of,
 892     Views* pviews)
 893 {
 894   unsigned int shnum = this->shnum();
 895   Sized_target<size, big_endian>* target =
 896     parameters->sized_target<size, big_endian>();
 897
 898   const Output_sections& out_sections(this->output_sections());
 899   const std::vector<Address>& out_offsets(this->section_offsets_);
 900
 901   Relocate_info<size, big_endian> relinfo;
 902   relinfo.symtab = symtab;
 903   relinfo.layout = layout;
 904   relinfo.object = this;
 905
 906   const unsigned char* p = pshdrs + This::shdr_size;
 907   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 908     {
 909       typename This::Shdr shdr(p);
 910
 911       unsigned int sh_type = shdr.get_sh_type();
 912       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 913         continue;
 914
 915       off_t sh_size = shdr.get_sh_size();
 916       if (sh_size == 0)
 917         continue;
 918
 919       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
 920       if (index >= this->shnum())
 921         {
 922           this->error(_("relocation section %u has bad info %u"),
 923                       i, index);
 924           continue;
 925         }
 926
 927       Output_section* os = out_sections[index];
 928       if (os == NULL)
 929         {
 930           // This relocation section is against a section which we
 931           // discarded.
 932           continue;
 933         }
 934       Address output_offset = out_offsets[index];
 935
 936       gold_assert((*pviews)[index].view != NULL);
 937       if (parameters->options().relocatable())
 938         gold_assert((*pviews)[i].view != NULL);
 939
 940       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 941         {
 942           gold_error(_("relocation section %u uses unexpected "
 943                        "symbol table %u"),
 944                      i, this->adjust_shndx(shdr.get_sh_link()));
 945           continue;
 946         }
 947
 948       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
 949                                                     sh_size, true, false);
 950
 951       unsigned int reloc_size;
 952       if (sh_type == elfcpp::SHT_REL)
 953         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 954       else
 955         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 956
 957       if (reloc_size != shdr.get_sh_entsize())
 958         {
 959           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
 960                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 961                      reloc_size);
 962           continue;
 963         }
 964
 965       size_t reloc_count = sh_size / reloc_size;
 966       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 967         {
 968           gold_error(_("reloc section %u size %lu uneven"),
 969                      i, static_cast<unsigned long>(sh_size));
 970           continue;
 971         }
 972
 973       gold_assert(output_offset != invalid_address
 974                   || this->relocs_must_follow_section_writes());
 975
 976       relinfo.reloc_shndx = i;
 977       relinfo.reloc_shdr = p;
 978       relinfo.data_shndx = index;
 979       relinfo.data_shdr = pshdrs + index * This::shdr_size;
 980       unsigned char* view = (*pviews)[index].view;
 981       Address address = (*pviews)[index].address;
 982       section_size_type view_size = (*pviews)[index].view_size;
 983
 984       Reloc_symbol_changes* reloc_map = NULL;
 985       if (this->uses_split_stack() && output_offset != invalid_address)
 986         {
 987           typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
 988           if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
 989             this->split_stack_adjust(symtab, pshdrs, sh_type, index,
 990                                      prelocs, reloc_count, view, view_size,
 991                                      &reloc_map);
 992         }
 993
 994       if (!parameters->options().relocatable())
 995         {
 996           target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
 997                                    output_offset == invalid_address,
 998                                    view, address, view_size, reloc_map);
 999           if (parameters->options().emit_relocs())
1000             this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
1001                               os, output_offset, view, address, view_size,
1002                               (*pviews)[i].view, (*pviews)[i].view_size);
1003           if (parameters->incremental())
1004             this->incremental_relocs_write(&relinfo, sh_type, prelocs,
1005                                            reloc_count, os, output_offset, of);
1006         }
1007       else
1008         {
1009           Relocatable_relocs* rr = this->relocatable_relocs(i);
1010           target->relocate_for_relocatable(&relinfo, sh_type, prelocs,
1011                                            reloc_count, os, output_offset, rr,
1012                                            view, address, view_size,
1013                                            (*pviews)[i].view,
1014                                            (*pviews)[i].view_size);
1015         }
1016     }
1017 }
1018
1019 // Emit the relocs for --emit-relocs.
1020
1021 template<int size, bool big_endian>
1022 void
1023 Sized_relobj<size, big_endian>::emit_relocs(
1024     const Relocate_info<size, big_endian>* relinfo,
1025     unsigned int i,
1026     unsigned int sh_type,
1027     const unsigned char* prelocs,
1028     size_t reloc_count,
1029     Output_section* output_section,
1030     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
1031     unsigned char* view,
1032     typename elfcpp::Elf_types<size>::Elf_Addr address,
1033     section_size_type view_size,
1034     unsigned char* reloc_view,
1035     section_size_type reloc_view_size)
1036 {
1037   if (sh_type == elfcpp::SHT_REL)
1038     this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
1039                                                reloc_count, output_section,
1040                                                offset_in_output_section,
1041                                                view, address, view_size,
1042                                                reloc_view, reloc_view_size);
1043   else
1044     {
1045       gold_assert(sh_type == elfcpp::SHT_RELA);
1046       this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
1047                                                   reloc_count, output_section,
1048                                                   offset_in_output_section,
1049                                                   view, address, view_size,
1050                                                   reloc_view, reloc_view_size);
1051     }
1052 }
1053
1054 // Emit the relocs for --emit-relocs, templatized on the type of the
1055 // relocation section.
1056
1057 template<int size, bool big_endian>
1058 template<int sh_type>
1059 void
1060 Sized_relobj<size, big_endian>::emit_relocs_reltype(
1061     const Relocate_info<size, big_endian>* relinfo,
1062     unsigned int i,
1063     const unsigned char* prelocs,
1064     size_t reloc_count,
1065     Output_section* output_section,
1066     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
1067     unsigned char* view,
1068     typename elfcpp::Elf_types<size>::Elf_Addr address,
1069     section_size_type view_size,
1070     unsigned char* reloc_view,
1071     section_size_type reloc_view_size)
1072 {
1073   const Relocatable_relocs* rr = this->relocatable_relocs(i);
1074   relocate_for_relocatable<size, big_endian, sh_type>(
1075     relinfo,
1076     prelocs,
1077     reloc_count,
1078     output_section,
1079     offset_in_output_section,
1080     rr,
1081     view,
1082     address,
1083     view_size,
1084     reloc_view,
1085     reloc_view_size);
1086 }
1087
1088 // Write the incremental relocs.
1089
1090 template<int size, bool big_endian>
1091 void
1092 Sized_relobj<size, big_endian>::incremental_relocs_write(
1093     const Relocate_info<size, big_endian>* relinfo,
1094     unsigned int sh_type,
1095     const unsigned char* prelocs,
1096     size_t reloc_count,
1097     Output_section* output_section,
1098     Address output_offset,
1099     Output_file* of)
1100 {
1101   if (sh_type == elfcpp::SHT_REL)
1102     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1103         relinfo,
1104         prelocs,
1105         reloc_count,
1106         output_section,
1107         output_offset,
1108         of);
1109   else
1110     {
1111       gold_assert(sh_type == elfcpp::SHT_RELA);
1112       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1113           relinfo,
1114           prelocs,
1115           reloc_count,
1116           output_section,
1117           output_offset,
1118           of);
1119     }
1120 }
1121
1122 // Write the incremental relocs, templatized on the type of the
1123 // relocation section.
1124
1125 template<int size, bool big_endian>
1126 template<int sh_type>
1127 void
1128 Sized_relobj<size, big_endian>::incremental_relocs_write_reltype(
1129     const Relocate_info<size, big_endian>* relinfo,
1130     const unsigned char* prelocs,
1131     size_t reloc_count,
1132     Output_section* output_section,
1133     Address output_offset,
1134     Output_file* of)
1135 {
1136   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1137   const unsigned int reloc_size =
1138       Reloc_types<sh_type, size, big_endian>::reloc_size;
1139   const unsigned int sizeof_addr = size / 8;
1140   const unsigned int incr_reloc_size = 8 + 2 * sizeof_addr;
1141
1142   unsigned int out_shndx = output_section->out_shndx();
1143
1144   // Get a view for the .gnu_incremental_relocs section.
1145
1146   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1147   gold_assert(inputs != NULL);
1148   const off_t relocs_off = inputs->relocs_section()->offset();
1149   const off_t relocs_size = inputs->relocs_section()->data_size();
1150   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1151
1152   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1153     {
1154       Reloc reloc(prelocs);
1155
1156       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1157       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1158       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1159
1160       if (r_sym < this->local_symbol_count_)
1161         continue;
1162
1163       // Get the new offset--the location in the output section where
1164       // this relocation should be applied.
1165
1166       Address offset = reloc.get_r_offset();
1167       if (output_offset != invalid_address)
1168         offset += output_offset;
1169       else
1170         {
1171           section_offset_type sot_offset =
1172               convert_types<section_offset_type, Address>(offset);
1173           section_offset_type new_sot_offset =
1174               output_section->output_offset(relinfo->object,
1175                                             relinfo->data_shndx,
1176                                             sot_offset);
1177           gold_assert(new_sot_offset != -1);
1178           offset += new_sot_offset;
1179         }
1180
1181       // Get the addend.
1182       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1183       if (sh_type == elfcpp::SHT_RELA)
1184         addend =
1185             Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1186       else
1187         {
1188           // FIXME: Get the addend for SHT_REL.
1189           addend = 0;
1190         }
1191
1192       // Get the index of the output relocation.
1193
1194       unsigned int reloc_index =
1195           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1196
1197       // Write the relocation.
1198
1199       unsigned char* pov = view + reloc_index * incr_reloc_size;
1200       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1201       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1202       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1203       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1204       of->write_output_view(pov - view, incr_reloc_size, view);
1205     }
1206 }
1207
1208 // Create merge hash tables for the local symbols.  These are used to
1209 // speed up relocations.
1210
1211 template<int size, bool big_endian>
1212 void
1213 Sized_relobj<size, big_endian>::initialize_input_to_output_maps()
1214 {
1215   const unsigned int loccount = this->local_symbol_count_;
1216   for (unsigned int i = 1; i < loccount; ++i)
1217     {
1218       Symbol_value<size>& lv(this->local_values_[i]);
1219       lv.initialize_input_to_output_map(this);
1220     }
1221 }
1222
1223 // Free merge hash tables for the local symbols.
1224
1225 template<int size, bool big_endian>
1226 void
1227 Sized_relobj<size, big_endian>::free_input_to_output_maps()
1228 {
1229   const unsigned int loccount = this->local_symbol_count_;
1230   for (unsigned int i = 1; i < loccount; ++i)
1231     {
1232       Symbol_value<size>& lv(this->local_values_[i]);
1233       lv.free_input_to_output_map();
1234     }
1235 }
1236
1237 // If an object was compiled with -fsplit-stack, this is called to
1238 // check whether any relocations refer to functions defined in objects
1239 // which were not compiled with -fsplit-stack.  If they were, then we
1240 // need to apply some target-specific adjustments to request
1241 // additional stack space.
1242
1243 template<int size, bool big_endian>
1244 void
1245 Sized_relobj<size, big_endian>::split_stack_adjust(
1246     const Symbol_table* symtab,
1247     const unsigned char* pshdrs,
1248     unsigned int sh_type,
1249     unsigned int shndx,
1250     const unsigned char* prelocs,
1251     size_t reloc_count,
1252     unsigned char* view,
1253     section_size_type view_size,
1254     Reloc_symbol_changes** reloc_map)
1255 {
1256   if (sh_type == elfcpp::SHT_REL)
1257     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1258                                                       prelocs, reloc_count,
1259                                                       view, view_size,
1260                                                       reloc_map);
1261   else
1262     {
1263       gold_assert(sh_type == elfcpp::SHT_RELA);
1264       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1265                                                          prelocs, reloc_count,
1266                                                          view, view_size,
1267                                                          reloc_map);
1268     }
1269 }
1270
1271 // Adjust for -fsplit-stack, templatized on the type of the relocation
1272 // section.
1273
1274 template<int size, bool big_endian>
1275 template<int sh_type>
1276 void
1277 Sized_relobj<size, big_endian>::split_stack_adjust_reltype(
1278     const Symbol_table* symtab,
1279     const unsigned char* pshdrs,
1280     unsigned int shndx,
1281     const unsigned char* prelocs,
1282     size_t reloc_count,
1283     unsigned char* view,
1284     section_size_type view_size,
1285     Reloc_symbol_changes** reloc_map)
1286 {
1287   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1288   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1289
1290   size_t local_count = this->local_symbol_count();
1291
1292   std::vector<section_offset_type> non_split_refs;
1293
1294   const unsigned char* pr = prelocs;
1295   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1296     {
1297       Reltype reloc(pr);
1298
1299       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1300       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1301       if (r_sym < local_count)
1302         continue;
1303
1304       const Symbol* gsym = this->global_symbol(r_sym);
1305       gold_assert(gsym != NULL);
1306       if (gsym->is_forwarder())
1307         gsym = symtab->resolve_forwards(gsym);
1308
1309       // See if this relocation refers to a function defined in an
1310       // object compiled without -fsplit-stack.  Note that we don't
1311       // care about the type of relocation--this means that in some
1312       // cases we will ask for a large stack unnecessarily, but this
1313       // is not fatal.  FIXME: Some targets have symbols which are
1314       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1315       if (!gsym->is_undefined()
1316           && gsym->source() == Symbol::FROM_OBJECT
1317           && !gsym->object()->uses_split_stack())
1318         {
1319           unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info());
1320           if (parameters->target().is_call_to_non_split(gsym, r_type))
1321             {
1322               section_offset_type offset =
1323                 convert_to_section_size_type(reloc.get_r_offset());
1324               non_split_refs.push_back(offset);
1325             }
1326         }
1327     }
1328
1329   if (non_split_refs.empty())
1330     return;
1331
1332   // At this point, every entry in NON_SPLIT_REFS indicates a
1333   // relocation which refers to a function in an object compiled
1334   // without -fsplit-stack.  We now have to convert that list into a
1335   // set of offsets to functions.  First, we find all the functions.
1336
1337   Function_offsets function_offsets;
1338   this->find_functions(pshdrs, shndx, &function_offsets);
1339   if (function_offsets.empty())
1340     return;
1341
1342   // Now get a list of the function with references to non split-stack
1343   // code.
1344
1345   Function_offsets calls_non_split;
1346   for (std::vector<section_offset_type>::const_iterator p
1347          = non_split_refs.begin();
1348        p != non_split_refs.end();
1349        ++p)
1350     {
1351       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1352       if (low == function_offsets.end())
1353         --low;
1354       else if (low->first == *p)
1355         ;
1356       else if (low == function_offsets.begin())
1357         continue;
1358       else
1359         --low;
1360
1361       calls_non_split.insert(*low);
1362     }
1363   if (calls_non_split.empty())
1364     return;
1365
1366   // Now we have a set of functions to adjust.  The adjustments are
1367   // target specific.  Besides changing the output section view
1368   // however, it likes, the target may request a relocation change
1369   // from one global symbol name to another.
1370
1371   for (Function_offsets::const_iterator p = calls_non_split.begin();
1372        p != calls_non_split.end();
1373        ++p)
1374     {
1375       std::string from;
1376       std::string to;
1377       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1378                                            view, view_size, &from, &to);
1379       if (!from.empty())
1380         {
1381           gold_assert(!to.empty());
1382           Symbol* tosym = NULL;
1383
1384           // Find relocations in the relevant function which are for
1385           // FROM.
1386           pr = prelocs;
1387           for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1388             {
1389               Reltype reloc(pr);
1390
1391               typename elfcpp::Elf_types<size>::Elf_WXword r_info =
1392                 reloc.get_r_info();
1393               unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1394               if (r_sym < local_count)
1395                 continue;
1396
1397               section_offset_type offset =
1398                 convert_to_section_size_type(reloc.get_r_offset());
1399               if (offset < p->first
1400                   || (offset
1401                       >= (p->first
1402                           + static_cast<section_offset_type>(p->second))))
1403                 continue;
1404
1405               const Symbol* gsym = this->global_symbol(r_sym);
1406               if (from == gsym->name())
1407                 {
1408                   if (tosym == NULL)
1409                     {
1410                       tosym = symtab->lookup(to.c_str());
1411                       if (tosym == NULL)
1412                         {
1413                           this->error(_("could not convert call "
1414                                         "to '%s' to '%s'"),
1415                                       from.c_str(), to.c_str());
1416                           break;
1417                         }
1418                     }
1419
1420                   if (*reloc_map == NULL)
1421                     *reloc_map = new Reloc_symbol_changes(reloc_count);
1422                   (*reloc_map)->set(i, tosym);
1423                 }
1424             }
1425         }
1426     }
1427 }
1428
1429 // Find all the function in this object defined in section SHNDX.
1430 // Store their offsets in the section in FUNCTION_OFFSETS.
1431
1432 template<int size, bool big_endian>
1433 void
1434 Sized_relobj<size, big_endian>::find_functions(
1435     const unsigned char* pshdrs,
1436     unsigned int shndx,
1437     Sized_relobj<size, big_endian>::Function_offsets* function_offsets)
1438 {
1439   // We need to read the symbols to find the functions.  If we wanted
1440   // to, we could cache reading the symbols across all sections in the
1441   // object.
1442   const unsigned int symtab_shndx = this->symtab_shndx_;
1443   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1444   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1445
1446   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1447     symtabshdr.get_sh_size();
1448   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1449                                               sh_size, true, true);
1450
1451   const int sym_size = This::sym_size;
1452   const unsigned int symcount = sh_size / sym_size;
1453   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1454     {
1455       typename elfcpp::Sym<size, big_endian> isym(psyms);
1456
1457       // FIXME: Some targets can have functions which do not have type
1458       // STT_FUNC, e.g., STT_ARM_TFUNC.
1459       if (isym.get_st_type() != elfcpp::STT_FUNC
1460           || isym.get_st_size() == 0)
1461         continue;
1462
1463       bool is_ordinary;
1464       unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1465                                                       &is_ordinary);
1466       if (!is_ordinary || sym_shndx != shndx)
1467         continue;
1468
1469       section_offset_type value =
1470         convert_to_section_size_type(isym.get_st_value());
1471       section_size_type fnsize =
1472         convert_to_section_size_type(isym.get_st_size());
1473
1474       (*function_offsets)[value] = fnsize;
1475     }
1476 }
1477
1478 // Class Merged_symbol_value.
1479
1480 template<int size>
1481 void
1482 Merged_symbol_value<size>::initialize_input_to_output_map(
1483     const Relobj* object,
1484     unsigned int input_shndx)
1485 {
1486   Object_merge_map* map = object->merge_map();
1487   map->initialize_input_to_output_map<size>(input_shndx,
1488                                             this->output_start_address_,
1489                                             &this->output_addresses_);
1490 }
1491
1492 // Get the output value corresponding to an input offset if we
1493 // couldn't find it in the hash table.
1494
1495 template<int size>
1496 typename elfcpp::Elf_types<size>::Elf_Addr
1497 Merged_symbol_value<size>::value_from_output_section(
1498     const Relobj* object,
1499     unsigned int input_shndx,
1500     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1501 {
1502   section_offset_type output_offset;
1503   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
1504                                                       input_offset,
1505                                                       &output_offset);
1506
1507   // If this assertion fails, it means that some relocation was
1508   // against a portion of an input merge section which we didn't map
1509   // to the output file and we didn't explicitly discard.  We should
1510   // always map all portions of input merge sections.
1511   gold_assert(found);
1512
1513   if (output_offset == -1)
1514     return 0;
1515   else
1516     return this->output_start_address_ + output_offset;
1517 }
1518
1519 // Track_relocs methods.
1520
1521 // Initialize the class to track the relocs.  This gets the object,
1522 // the reloc section index, and the type of the relocs.  This returns
1523 // false if something goes wrong.
1524
1525 template<int size, bool big_endian>
1526 bool
1527 Track_relocs<size, big_endian>::initialize(
1528     Object* object,
1529     unsigned int reloc_shndx,
1530     unsigned int reloc_type)
1531 {
1532   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1533   // section for the .eh_frame section.  We can't handle that case.
1534   if (reloc_shndx == -1U)
1535     return false;
1536
1537   // If RELOC_SHNDX is 0, there is no reloc section.
1538   if (reloc_shndx == 0)
1539     return true;
1540
1541   // Get the contents of the reloc section.
1542   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1543
1544   if (reloc_type == elfcpp::SHT_REL)
1545     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1546   else if (reloc_type == elfcpp::SHT_RELA)
1547     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1548   else
1549     gold_unreachable();
1550
1551   if (this->len_ % this->reloc_size_ != 0)
1552     {
1553       object->error(_("reloc section size %zu is not a multiple of "
1554                       "reloc size %d\n"),
1555                     static_cast<size_t>(this->len_),
1556                     this->reloc_size_);
1557       return false;
1558     }
1559
1560   return true;
1561 }
1562
1563 // Return the offset of the next reloc, or -1 if there isn't one.
1564
1565 template<int size, bool big_endian>
1566 off_t
1567 Track_relocs<size, big_endian>::next_offset() const
1568 {
1569   if (this->pos_ >= this->len_)
1570     return -1;
1571
1572   // Rel and Rela start out the same, so we can always use Rel to find
1573   // the r_offset value.
1574   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1575   return rel.get_r_offset();
1576 }
1577
1578 // Return the index of the symbol referenced by the next reloc, or -1U
1579 // if there aren't any more relocs.
1580
1581 template<int size, bool big_endian>
1582 unsigned int
1583 Track_relocs<size, big_endian>::next_symndx() const
1584 {
1585   if (this->pos_ >= this->len_)
1586     return -1U;
1587
1588   // Rel and Rela start out the same, so we can use Rel to find the
1589   // symbol index.
1590   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1591   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1592 }
1593
1594 // Return the addend of the next reloc, or 0 if there isn't one.
1595
1596 template<int size, bool big_endian>
1597 uint64_t
1598 Track_relocs<size, big_endian>::next_addend() const
1599 {
1600   if (this->pos_ >= this->len_)
1601     return 0;
1602   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1603     return 0;
1604   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1605   return rela.get_r_addend();
1606 }
1607
1608 // Advance to the next reloc whose r_offset is greater than or equal
1609 // to OFFSET.  Return the number of relocs we skip.
1610
1611 template<int size, bool big_endian>
1612 int
1613 Track_relocs<size, big_endian>::advance(off_t offset)
1614 {
1615   int ret = 0;
1616   while (this->pos_ < this->len_)
1617     {
1618       // Rel and Rela start out the same, so we can always use Rel to
1619       // find the r_offset value.
1620       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1621       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1622         break;
1623       ++ret;
1624       this->pos_ += this->reloc_size_;
1625     }
1626   return ret;
1627 }
1628
1629 // Instantiate the templates we need.
1630
1631 #ifdef HAVE_TARGET_32_LITTLE
1632 template
1633 void
1634 Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
1635 #endif
1636
1637 #ifdef HAVE_TARGET_32_BIG
1638 template
1639 void
1640 Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
1641 #endif
1642
1643 #ifdef HAVE_TARGET_64_LITTLE
1644 template
1645 void
1646 Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
1647 #endif
1648
1649 #ifdef HAVE_TARGET_64_BIG
1650 template
1651 void
1652 Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
1653 #endif
1654
1655 #ifdef HAVE_TARGET_32_LITTLE
1656 template
1657 void
1658 Sized_relobj<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1659                                               Layout* layout,
1660                                               Read_relocs_data* rd);
1661 #endif
1662
1663 #ifdef HAVE_TARGET_32_BIG
1664 template
1665 void
1666 Sized_relobj<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1667                                              Layout* layout,
1668                                              Read_relocs_data* rd);
1669 #endif
1670
1671 #ifdef HAVE_TARGET_64_LITTLE
1672 template
1673 void
1674 Sized_relobj<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1675                                               Layout* layout,
1676                                               Read_relocs_data* rd);
1677 #endif
1678
1679 #ifdef HAVE_TARGET_64_BIG
1680 template
1681 void
1682 Sized_relobj<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1683                                              Layout* layout,
1684                                              Read_relocs_data* rd);
1685 #endif
1686
1687 #ifdef HAVE_TARGET_32_LITTLE
1688 template
1689 void
1690 Sized_relobj<32, false>::do_scan_relocs(Symbol_table* symtab,
1691                                         Layout* layout,
1692                                         Read_relocs_data* rd);
1693 #endif
1694
1695 #ifdef HAVE_TARGET_32_BIG
1696 template
1697 void
1698 Sized_relobj<32, true>::do_scan_relocs(Symbol_table* symtab,
1699                                        Layout* layout,
1700                                        Read_relocs_data* rd);
1701 #endif
1702
1703 #ifdef HAVE_TARGET_64_LITTLE
1704 template
1705 void
1706 Sized_relobj<64, false>::do_scan_relocs(Symbol_table* symtab,
1707                                         Layout* layout,
1708                                         Read_relocs_data* rd);
1709 #endif
1710
1711 #ifdef HAVE_TARGET_64_BIG
1712 template
1713 void
1714 Sized_relobj<64, true>::do_scan_relocs(Symbol_table* symtab,
1715                                        Layout* layout,
1716                                        Read_relocs_data* rd);
1717 #endif
1718
1719 #ifdef HAVE_TARGET_32_LITTLE
1720 template
1721 void
1722 Sized_relobj<32, false>::do_relocate(const Symbol_table* symtab,
1723                                      const Layout* layout,
1724                                      Output_file* of);
1725 #endif
1726
1727 #ifdef HAVE_TARGET_32_BIG
1728 template
1729 void
1730 Sized_relobj<32, true>::do_relocate(const Symbol_table* symtab,
1731                                     const Layout* layout,
1732                                     Output_file* of);
1733 #endif
1734
1735 #ifdef HAVE_TARGET_64_LITTLE
1736 template
1737 void
1738 Sized_relobj<64, false>::do_relocate(const Symbol_table* symtab,
1739                                      const Layout* layout,
1740                                      Output_file* of);
1741 #endif
1742
1743 #ifdef HAVE_TARGET_64_BIG
1744 template
1745 void
1746 Sized_relobj<64, true>::do_relocate(const Symbol_table* symtab,
1747                                     const Layout* layout,
1748                                     Output_file* of);
1749 #endif
1750
1751 #ifdef HAVE_TARGET_32_LITTLE
1752 template
1753 void
1754 Sized_relobj<32, false>::do_relocate_sections(
1755     const Symbol_table* symtab,
1756     const Layout* layout,
1757     const unsigned char* pshdrs,
1758     Output_file* of,
1759     Views* pviews);
1760 #endif
1761
1762 #ifdef HAVE_TARGET_32_BIG
1763 template
1764 void
1765 Sized_relobj<32, true>::do_relocate_sections(
1766     const Symbol_table* symtab,
1767     const Layout* layout,
1768     const unsigned char* pshdrs,
1769     Output_file* of,
1770     Views* pviews);
1771 #endif
1772
1773 #ifdef HAVE_TARGET_64_LITTLE
1774 template
1775 void
1776 Sized_relobj<64, false>::do_relocate_sections(
1777     const Symbol_table* symtab,
1778     const Layout* layout,
1779     const unsigned char* pshdrs,
1780     Output_file* of,
1781     Views* pviews);
1782 #endif
1783
1784 #ifdef HAVE_TARGET_64_BIG
1785 template
1786 void
1787 Sized_relobj<64, true>::do_relocate_sections(
1788     const Symbol_table* symtab,
1789     const Layout* layout,
1790     const unsigned char* pshdrs,
1791     Output_file* of,
1792     Views* pviews);
1793 #endif
1794
1795 #ifdef HAVE_TARGET_32_LITTLE
1796 template
1797 void
1798 Sized_relobj<32, false>::initialize_input_to_output_maps();
1799
1800 template
1801 void
1802 Sized_relobj<32, false>::free_input_to_output_maps();
1803 #endif
1804
1805 #ifdef HAVE_TARGET_32_BIG
1806 template
1807 void
1808 Sized_relobj<32, true>::initialize_input_to_output_maps();
1809
1810 template
1811 void
1812 Sized_relobj<32, true>::free_input_to_output_maps();
1813 #endif
1814
1815 #ifdef HAVE_TARGET_64_LITTLE
1816 template
1817 void
1818 Sized_relobj<64, false>::initialize_input_to_output_maps();
1819
1820 template
1821 void
1822 Sized_relobj<64, false>::free_input_to_output_maps();
1823 #endif
1824
1825 #ifdef HAVE_TARGET_64_BIG
1826 template
1827 void
1828 Sized_relobj<64, true>::initialize_input_to_output_maps();
1829
1830 template
1831 void
1832 Sized_relobj<64, true>::free_input_to_output_maps();
1833 #endif
1834
1835 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1836 template
1837 class Merged_symbol_value<32>;
1838 #endif
1839
1840 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1841 template
1842 class Merged_symbol_value<64>;
1843 #endif
1844
1845 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1846 template
1847 class Symbol_value<32>;
1848 #endif
1849
1850 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1851 template
1852 class Symbol_value<64>;
1853 #endif
1854
1855 #ifdef HAVE_TARGET_32_LITTLE
1856 template
1857 class Track_relocs<32, false>;
1858 #endif
1859
1860 #ifdef HAVE_TARGET_32_BIG
1861 template
1862 class Track_relocs<32, true>;
1863 #endif
1864
1865 #ifdef HAVE_TARGET_64_LITTLE
1866 template
1867 class Track_relocs<64, false>;
1868 #endif
1869
1870 #ifdef HAVE_TARGET_64_BIG
1871 template
1872 class Track_relocs<64, true>;
1873 #endif
1874
1875 } // End namespace gold.