gold/reloc.cc

   1 // reloc.cc -- relocate input files for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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   Task_token* token = this->object_->token();
  60   if (token != NULL)
  61     tl->add(this, token);
  62 }
  63
  64 // Read the relocations and then start a Scan_relocs_task.
  65
  66 void
  67 Read_relocs::run(Workqueue* workqueue)
  68 {
  69   Read_relocs_data* rd = new Read_relocs_data;
  70   this->object_->read_relocs(rd);
  71   this->object_->set_relocs_data(rd);
  72   this->object_->release();
  73
  74   // If garbage collection or identical comdat folding is desired, we
  75   // process the relocs first before scanning them.  Scanning of relocs is
  76   // done only after garbage or identical sections is identified.
  77   if (parameters->options().gc_sections()
  78       || parameters->options().icf_enabled())
  79     {
  80       workqueue->queue_next(new Gc_process_relocs(this->symtab_,
  81                                                   this->layout_,
  82                                                   this->object_, rd,
  83                                                   this->this_blocker_,
  84                                                   this->next_blocker_));
  85     }
  86   else
  87     {
  88       workqueue->queue_next(new Scan_relocs(this->symtab_, this->layout_,
  89                                             this->object_, rd,
  90                                             this->this_blocker_,
  91                                             this->next_blocker_));
  92     }
  93 }
  94
  95 // Return a debugging name for the task.
  96
  97 std::string
  98 Read_relocs::get_name() const
  99 {
 100   return "Read_relocs " + this->object_->name();
 101 }
 102
 103 // Gc_process_relocs methods.
 104
 105 Gc_process_relocs::~Gc_process_relocs()
 106 {
 107   if (this->this_blocker_ != NULL)
 108     delete this->this_blocker_;
 109 }
 110
 111 // These tasks process the relocations read by Read_relocs and
 112 // determine which sections are referenced and which are garbage.
 113 // This task is done only when --gc-sections is used.  This is blocked
 114 // by THIS_BLOCKER_.  It unblocks NEXT_BLOCKER_.
 115
 116 Task_token*
 117 Gc_process_relocs::is_runnable()
 118 {
 119   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 120     return this->this_blocker_;
 121   if (this->object_->is_locked())
 122     return this->object_->token();
 123   return NULL;
 124 }
 125
 126 void
 127 Gc_process_relocs::locks(Task_locker* tl)
 128 {
 129   tl->add(this, this->object_->token());
 130   tl->add(this, this->next_blocker_);
 131 }
 132
 133 void
 134 Gc_process_relocs::run(Workqueue*)
 135 {
 136   this->object_->gc_process_relocs(this->symtab_, this->layout_, this->rd_);
 137   this->object_->release();
 138 }
 139
 140 // Return a debugging name for the task.
 141
 142 std::string
 143 Gc_process_relocs::get_name() const
 144 {
 145   return "Gc_process_relocs " + this->object_->name();
 146 }
 147
 148 // Scan_relocs methods.
 149
 150 Scan_relocs::~Scan_relocs()
 151 {
 152   if (this->this_blocker_ != NULL)
 153     delete this->this_blocker_;
 154 }
 155
 156 // These tasks scan the relocations read by Read_relocs and mark up
 157 // the symbol table to indicate which relocations are required.  We
 158 // use a lock on the symbol table to keep them from interfering with
 159 // each other.
 160
 161 Task_token*
 162 Scan_relocs::is_runnable()
 163 {
 164   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 165     return this->this_blocker_;
 166   if (this->object_->is_locked())
 167     return this->object_->token();
 168   return NULL;
 169 }
 170
 171 // Return the locks we hold: one on the file, one on the symbol table
 172 // and one blocker.
 173
 174 void
 175 Scan_relocs::locks(Task_locker* tl)
 176 {
 177   Task_token* token = this->object_->token();
 178   if (token != NULL)
 179     tl->add(this, token);
 180   tl->add(this, this->next_blocker_);
 181 }
 182
 183 // Scan the relocs.
 184
 185 void
 186 Scan_relocs::run(Workqueue*)
 187 {
 188   this->object_->scan_relocs(this->symtab_, this->layout_, this->rd_);
 189   delete this->rd_;
 190   this->rd_ = NULL;
 191   this->object_->release();
 192 }
 193
 194 // Return a debugging name for the task.
 195
 196 std::string
 197 Scan_relocs::get_name() const
 198 {
 199   return "Scan_relocs " + this->object_->name();
 200 }
 201
 202 // Relocate_task methods.
 203
 204 // We may have to wait for the output sections to be written.
 205
 206 Task_token*
 207 Relocate_task::is_runnable()
 208 {
 209   if (this->object_->relocs_must_follow_section_writes()
 210       && this->output_sections_blocker_->is_blocked())
 211     return this->output_sections_blocker_;
 212
 213   if (this->object_->is_locked())
 214     return this->object_->token();
 215
 216   return NULL;
 217 }
 218
 219 // We want to lock the file while we run.  We want to unblock
 220 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
 221 // INPUT_SECTIONS_BLOCKER may be NULL.
 222
 223 void
 224 Relocate_task::locks(Task_locker* tl)
 225 {
 226   if (this->input_sections_blocker_ != NULL)
 227     tl->add(this, this->input_sections_blocker_);
 228   tl->add(this, this->final_blocker_);
 229   Task_token* token = this->object_->token();
 230   if (token != NULL)
 231     tl->add(this, token);
 232 }
 233
 234 // Run the task.
 235
 236 void
 237 Relocate_task::run(Workqueue*)
 238 {
 239   this->object_->relocate(this->symtab_, this->layout_, this->of_);
 240
 241   // This is normally the last thing we will do with an object, so
 242   // uncache all views.
 243   this->object_->clear_view_cache_marks();
 244
 245   this->object_->release();
 246 }
 247
 248 // Return a debugging name for the task.
 249
 250 std::string
 251 Relocate_task::get_name() const
 252 {
 253   return "Relocate_task " + this->object_->name();
 254 }
 255
 256 // Read the relocs and local symbols from the object file and store
 257 // the information in RD.
 258
 259 template<int size, bool big_endian>
 260 void
 261 Sized_relobj_file<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
 262 {
 263   rd->relocs.clear();
 264
 265   unsigned int shnum = this->shnum();
 266   if (shnum == 0)
 267     return;
 268
 269   rd->relocs.reserve(shnum / 2);
 270
 271   const Output_sections& out_sections(this->output_sections());
 272   const std::vector<Address>& out_offsets(this->section_offsets());
 273
 274   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 275                                                shnum * This::shdr_size,
 276                                                true, true);
 277   // Skip the first, dummy, section.
 278   const unsigned char* ps = pshdrs + This::shdr_size;
 279   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
 280     {
 281       typename This::Shdr shdr(ps);
 282
 283       unsigned int sh_type = shdr.get_sh_type();
 284       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 285         continue;
 286
 287       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
 288       if (shndx >= shnum)
 289         {
 290           this->error(_("relocation section %u has bad info %u"),
 291                       i, shndx);
 292           continue;
 293         }
 294
 295       Output_section* os = out_sections[shndx];
 296       if (os == NULL)
 297         continue;
 298
 299       // We are scanning relocations in order to fill out the GOT and
 300       // PLT sections.  Relocations for sections which are not
 301       // allocated (typically debugging sections) should not add new
 302       // GOT and PLT entries.  So we skip them unless this is a
 303       // relocatable link or we need to emit relocations.  FIXME: What
 304       // should we do if a linker script maps a section with SHF_ALLOC
 305       // clear to a section with SHF_ALLOC set?
 306       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
 307       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
 308                                    != 0);
 309       if (!is_section_allocated
 310           && !parameters->options().relocatable()
 311           && !parameters->options().emit_relocs()
 312           && !parameters->incremental())
 313         continue;
 314
 315       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 316         {
 317           this->error(_("relocation section %u uses unexpected "
 318                         "symbol table %u"),
 319                       i, this->adjust_shndx(shdr.get_sh_link()));
 320           continue;
 321         }
 322
 323       off_t sh_size = shdr.get_sh_size();
 324
 325       if (sh_size == 0)
 326         continue;
 327
 328       unsigned int reloc_size;
 329       if (sh_type == elfcpp::SHT_REL)
 330         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 331       else
 332         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 333       if (reloc_size != shdr.get_sh_entsize())
 334         {
 335           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
 336                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 337                       reloc_size);
 338           continue;
 339         }
 340
 341       size_t reloc_count = sh_size / reloc_size;
 342       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 343         {
 344           this->error(_("reloc section %u size %lu uneven"),
 345                       i, static_cast<unsigned long>(sh_size));
 346           continue;
 347         }
 348
 349       rd->relocs.push_back(Section_relocs());
 350       Section_relocs& sr(rd->relocs.back());
 351       sr.reloc_shndx = i;
 352       sr.data_shndx = shndx;
 353       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
 354                                            true, true);
 355       sr.sh_type = sh_type;
 356       sr.reloc_count = reloc_count;
 357       sr.output_section = os;
 358       sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
 359       sr.is_data_section_allocated = is_section_allocated;
 360     }
 361
 362   // Read the local symbols.
 363   gold_assert(this->symtab_shndx_ != -1U);
 364   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
 365     rd->local_symbols = NULL;
 366   else
 367     {
 368       typename This::Shdr symtabshdr(pshdrs
 369                                      + this->symtab_shndx_ * This::shdr_size);
 370       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
 371       const int sym_size = This::sym_size;
 372       const unsigned int loccount = this->local_symbol_count_;
 373       gold_assert(loccount == symtabshdr.get_sh_info());
 374       off_t locsize = loccount * sym_size;
 375       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
 376                                                  locsize, true, true);
 377     }
 378 }
 379
 380 // Process the relocs to generate mappings from source sections to referenced
 381 // sections.  This is used during garbage collection to determine garbage
 382 // sections.
 383
 384 template<int size, bool big_endian>
 385 void
 386 Sized_relobj_file<size, big_endian>::do_gc_process_relocs(Symbol_table* symtab,
 387                                                           Layout* layout,
 388                                                           Read_relocs_data* rd)
 389 {
 390   Sized_target<size, big_endian>* target =
 391     parameters->sized_target<size, big_endian>();
 392
 393   const unsigned char* local_symbols;
 394   if (rd->local_symbols == NULL)
 395     local_symbols = NULL;
 396   else
 397     local_symbols = rd->local_symbols->data();
 398
 399   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 400        p != rd->relocs.end();
 401        ++p)
 402     {
 403       if (!parameters->options().relocatable())
 404           {
 405             // As noted above, when not generating an object file, we
 406             // only scan allocated sections.  We may see a non-allocated
 407             // section here if we are emitting relocs.
 408             if (p->is_data_section_allocated)
 409               target->gc_process_relocs(symtab, layout, this,
 410                                         p->data_shndx, p->sh_type,
 411                                         p->contents->data(), p->reloc_count,
 412                                         p->output_section,
 413                                         p->needs_special_offset_handling,
 414                                         this->local_symbol_count_,
 415                                         local_symbols);
 416         }
 417     }
 418 }
 419
 420
 421 // Scan the relocs and adjust the symbol table.  This looks for
 422 // relocations which require GOT/PLT/COPY relocations.
 423
 424 template<int size, bool big_endian>
 425 void
 426 Sized_relobj_file<size, big_endian>::do_scan_relocs(Symbol_table* symtab,
 427                                                Layout* layout,
 428                                                Read_relocs_data* rd)
 429 {
 430   Sized_target<size, big_endian>* target =
 431     parameters->sized_target<size, big_endian>();
 432
 433   const unsigned char* local_symbols;
 434   if (rd->local_symbols == NULL)
 435     local_symbols = NULL;
 436   else
 437     local_symbols = rd->local_symbols->data();
 438
 439   // For incremental links, allocate the counters for incremental relocations.
 440   if (layout->incremental_inputs() != NULL)
 441     this->allocate_incremental_reloc_counts();
 442
 443   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
 444        p != rd->relocs.end();
 445        ++p)
 446     {
 447       // When garbage collection is on, unreferenced sections are not included
 448       // in the link that would have been included normally. This is known only
 449       // after Read_relocs hence this check has to be done again.
 450       if (parameters->options().gc_sections()
 451           || parameters->options().icf_enabled())
 452         {
 453           if (p->output_section == NULL)
 454             continue;
 455         }
 456       if (!parameters->options().relocatable())
 457         {
 458           // As noted above, when not generating an object file, we
 459           // only scan allocated sections.  We may see a non-allocated
 460           // section here if we are emitting relocs.
 461           if (p->is_data_section_allocated)
 462             target->scan_relocs(symtab, layout, this, p->data_shndx,
 463                                 p->sh_type, p->contents->data(),
 464                                 p->reloc_count, p->output_section,
 465                                 p->needs_special_offset_handling,
 466                                 this->local_symbol_count_,
 467                                 local_symbols);
 468           if (parameters->options().emit_relocs())
 469             this->emit_relocs_scan(symtab, layout, local_symbols, p);
 470           if (layout->incremental_inputs() != NULL)
 471             this->incremental_relocs_scan(p);
 472         }
 473       else
 474         {
 475           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 476           gold_assert(rr != NULL);
 477           rr->set_reloc_count(p->reloc_count);
 478           target->scan_relocatable_relocs(symtab, layout, this,
 479                                           p->data_shndx, p->sh_type,
 480                                           p->contents->data(),
 481                                           p->reloc_count,
 482                                           p->output_section,
 483                                           p->needs_special_offset_handling,
 484                                           this->local_symbol_count_,
 485                                           local_symbols,
 486                                           rr);
 487         }
 488
 489       delete p->contents;
 490       p->contents = NULL;
 491     }
 492
 493   // For incremental links, finalize the allocation of relocations.
 494   if (layout->incremental_inputs() != NULL)
 495     this->finalize_incremental_relocs(layout, true);
 496
 497   if (rd->local_symbols != NULL)
 498     {
 499       delete rd->local_symbols;
 500       rd->local_symbols = NULL;
 501     }
 502 }
 503
 504 // This is a strategy class we use when scanning for --emit-relocs.
 505
 506 template<int sh_type>
 507 class Emit_relocs_strategy
 508 {
 509  public:
 510   // A local non-section symbol.
 511   inline Relocatable_relocs::Reloc_strategy
 512   local_non_section_strategy(unsigned int, Relobj*, unsigned int)
 513   { return Relocatable_relocs::RELOC_COPY; }
 514
 515   // A local section symbol.
 516   inline Relocatable_relocs::Reloc_strategy
 517   local_section_strategy(unsigned int, Relobj*)
 518   {
 519     if (sh_type == elfcpp::SHT_RELA)
 520       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 521     else
 522       {
 523         // The addend is stored in the section contents.  Since this
 524         // is not a relocatable link, we are going to apply the
 525         // relocation contents to the section as usual.  This means
 526         // that we have no way to record the original addend.  If the
 527         // original addend is not zero, there is basically no way for
 528         // the user to handle this correctly.  Caveat emptor.
 529         return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 530       }
 531   }
 532
 533   // A global symbol.
 534   inline Relocatable_relocs::Reloc_strategy
 535   global_strategy(unsigned int, Relobj*, unsigned int)
 536   { return Relocatable_relocs::RELOC_COPY; }
 537 };
 538
 539 // Scan the input relocations for --emit-relocs.
 540
 541 template<int size, bool big_endian>
 542 void
 543 Sized_relobj_file<size, big_endian>::emit_relocs_scan(
 544     Symbol_table* symtab,
 545     Layout* layout,
 546     const unsigned char* plocal_syms,
 547     const Read_relocs_data::Relocs_list::iterator& p)
 548 {
 549   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
 550   gold_assert(rr != NULL);
 551   rr->set_reloc_count(p->reloc_count);
 552
 553   if (p->sh_type == elfcpp::SHT_REL)
 554     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(symtab, layout,
 555                                                     plocal_syms, p, rr);
 556   else
 557     {
 558       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 559       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(symtab, layout,
 560                                                        plocal_syms, p, rr);
 561     }
 562 }
 563
 564 // Scan the input relocation for --emit-relocs, templatized on the
 565 // type of the relocation section.
 566
 567 template<int size, bool big_endian>
 568 template<int sh_type>
 569 void
 570 Sized_relobj_file<size, big_endian>::emit_relocs_scan_reltype(
 571     Symbol_table* symtab,
 572     Layout* layout,
 573     const unsigned char* plocal_syms,
 574     const Read_relocs_data::Relocs_list::iterator& p,
 575     Relocatable_relocs* rr)
 576 {
 577   scan_relocatable_relocs<size, big_endian, sh_type,
 578                           Emit_relocs_strategy<sh_type> >(
 579     symtab,
 580     layout,
 581     this,
 582     p->data_shndx,
 583     p->contents->data(),
 584     p->reloc_count,
 585     p->output_section,
 586     p->needs_special_offset_handling,
 587     this->local_symbol_count_,
 588     plocal_syms,
 589     rr);
 590 }
 591
 592 // Scan the input relocations for --incremental.
 593
 594 template<int size, bool big_endian>
 595 void
 596 Sized_relobj_file<size, big_endian>::incremental_relocs_scan(
 597     const Read_relocs_data::Relocs_list::iterator& p)
 598 {
 599   if (p->sh_type == elfcpp::SHT_REL)
 600     this->incremental_relocs_scan_reltype<elfcpp::SHT_REL>(p);
 601   else
 602     {
 603       gold_assert(p->sh_type == elfcpp::SHT_RELA);
 604       this->incremental_relocs_scan_reltype<elfcpp::SHT_RELA>(p);
 605     }
 606 }
 607
 608 // Scan the input relocation for --incremental, templatized on the
 609 // type of the relocation section.
 610
 611 template<int size, bool big_endian>
 612 template<int sh_type>
 613 void
 614 Sized_relobj_file<size, big_endian>::incremental_relocs_scan_reltype(
 615     const Read_relocs_data::Relocs_list::iterator& p)
 616 {
 617   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 618   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 619   const unsigned char* prelocs = p->contents->data();
 620   size_t reloc_count = p->reloc_count;
 621
 622   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 623     {
 624       Reltype reloc(prelocs);
 625
 626       if (p->needs_special_offset_handling
 627           && !p->output_section->is_input_address_mapped(this, p->data_shndx,
 628                                                          reloc.get_r_offset()))
 629         continue;
 630
 631       typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 632           reloc.get_r_info();
 633       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 634
 635       if (r_sym >= this->local_symbol_count_)
 636         this->count_incremental_reloc(r_sym - this->local_symbol_count_);
 637     }
 638 }
 639
 640 // Relocate the input sections and write out the local symbols.
 641
 642 template<int size, bool big_endian>
 643 void
 644 Sized_relobj_file<size, big_endian>::do_relocate(const Symbol_table* symtab,
 645                                                  const Layout* layout,
 646                                                  Output_file* of)
 647 {
 648   unsigned int shnum = this->shnum();
 649
 650   // Read the section headers.
 651   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
 652                                                shnum * This::shdr_size,
 653                                                true, true);
 654
 655   Views views;
 656   views.resize(shnum);
 657
 658   // Make two passes over the sections.  The first one copies the
 659   // section data to the output file.  The second one applies
 660   // relocations.
 661
 662   this->write_sections(layout, pshdrs, of, &views);
 663
 664   // To speed up relocations, we set up hash tables for fast lookup of
 665   // input offsets to output addresses.
 666   this->initialize_input_to_output_maps();
 667
 668   // Apply relocations.
 669
 670   this->relocate_sections(symtab, layout, pshdrs, of, &views);
 671
 672   // After we've done the relocations, we release the hash tables,
 673   // since we no longer need them.
 674   this->free_input_to_output_maps();
 675
 676   // Write out the accumulated views.
 677   for (unsigned int i = 1; i < shnum; ++i)
 678     {
 679       if (views[i].view != NULL)
 680         {
 681           if (views[i].is_ctors_reverse_view)
 682             this->reverse_words(views[i].view, views[i].view_size);
 683           if (!views[i].is_postprocessing_view)
 684             {
 685               if (views[i].is_input_output_view)
 686                 of->write_input_output_view(views[i].offset,
 687                                             views[i].view_size,
 688                                             views[i].view);
 689               else
 690                 of->write_output_view(views[i].offset, views[i].view_size,
 691                                       views[i].view);
 692             }
 693         }
 694     }
 695
 696   // Write out the local symbols.
 697   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
 698                             layout->symtab_xindex(), layout->dynsym_xindex(),
 699                             layout->symtab_section_offset());
 700 }
 701
 702 // Sort a Read_multiple vector by file offset.
 703 struct Read_multiple_compare
 704 {
 705   inline bool
 706   operator()(const File_read::Read_multiple_entry& rme1,
 707              const File_read::Read_multiple_entry& rme2) const
 708   { return rme1.file_offset < rme2.file_offset; }
 709 };
 710
 711 // Write section data to the output file.  PSHDRS points to the
 712 // section headers.  Record the views in *PVIEWS for use when
 713 // relocating.
 714
 715 template<int size, bool big_endian>
 716 void
 717 Sized_relobj_file<size, big_endian>::write_sections(const Layout* layout,
 718                                                     const unsigned char* pshdrs,
 719                                                     Output_file* of,
 720                                                     Views* pviews)
 721 {
 722   unsigned int shnum = this->shnum();
 723   const Output_sections& out_sections(this->output_sections());
 724   const std::vector<Address>& out_offsets(this->section_offsets());
 725
 726   File_read::Read_multiple rm;
 727   bool is_sorted = true;
 728
 729   const unsigned char* p = pshdrs + This::shdr_size;
 730   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 731     {
 732       View_size* pvs = &(*pviews)[i];
 733
 734       pvs->view = NULL;
 735
 736       const Output_section* os = out_sections[i];
 737       if (os == NULL)
 738         continue;
 739       Address output_offset = out_offsets[i];
 740
 741       typename This::Shdr shdr(p);
 742
 743       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
 744         continue;
 745
 746       if ((parameters->options().relocatable()
 747            || parameters->options().emit_relocs())
 748           && (shdr.get_sh_type() == elfcpp::SHT_REL
 749               || shdr.get_sh_type() == elfcpp::SHT_RELA)
 750           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 751         {
 752           // This is a reloc section in a relocatable link or when
 753           // emitting relocs.  We don't need to read the input file.
 754           // The size and file offset are stored in the
 755           // Relocatable_relocs structure.
 756           Relocatable_relocs* rr = this->relocatable_relocs(i);
 757           gold_assert(rr != NULL);
 758           Output_data* posd = rr->output_data();
 759           gold_assert(posd != NULL);
 760
 761           pvs->offset = posd->offset();
 762           pvs->view_size = posd->data_size();
 763           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
 764           pvs->address = posd->address();
 765           pvs->is_input_output_view = false;
 766           pvs->is_postprocessing_view = false;
 767           pvs->is_ctors_reverse_view = false;
 768
 769           continue;
 770         }
 771
 772       // In the normal case, this input section is simply mapped to
 773       // the output section at offset OUTPUT_OFFSET.
 774
 775       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
 776       // handled specially--e.g., a .eh_frame section.  The relocation
 777       // routines need to check for each reloc where it should be
 778       // applied.  For this case, we need an input/output view for the
 779       // entire contents of the section in the output file.  We don't
 780       // want to copy the contents of the input section to the output
 781       // section; the output section contents were already written,
 782       // and we waited for them in Relocate_task::is_runnable because
 783       // relocs_must_follow_section_writes is set for the object.
 784
 785       // Regardless of which of the above cases is true, we have to
 786       // check requires_postprocessing of the output section.  If that
 787       // is false, then we work with views of the output file
 788       // directly.  If it is true, then we work with a separate
 789       // buffer, and the output section is responsible for writing the
 790       // final data to the output file.
 791
 792       off_t output_section_offset;
 793       Address output_section_size;
 794       if (!os->requires_postprocessing())
 795         {
 796           output_section_offset = os->offset();
 797           output_section_size = convert_types<Address, off_t>(os->data_size());
 798         }
 799       else
 800         {
 801           output_section_offset = 0;
 802           output_section_size =
 803               convert_types<Address, off_t>(os->postprocessing_buffer_size());
 804         }
 805
 806       off_t view_start;
 807       section_size_type view_size;
 808       bool must_decompress = false;
 809       if (output_offset != invalid_address)
 810         {
 811           view_start = output_section_offset + output_offset;
 812           view_size = convert_to_section_size_type(shdr.get_sh_size());
 813           section_size_type uncompressed_size;
 814           if (this->section_is_compressed(i, &uncompressed_size))
 815             {
 816               view_size = uncompressed_size;
 817               must_decompress = true;
 818             }
 819         }
 820       else
 821         {
 822           view_start = output_section_offset;
 823           view_size = convert_to_section_size_type(output_section_size);
 824         }
 825
 826       if (view_size == 0)
 827         continue;
 828
 829       gold_assert(output_offset == invalid_address
 830                   || output_offset + view_size <= output_section_size);
 831
 832       unsigned char* view;
 833       if (os->requires_postprocessing())
 834         {
 835           unsigned char* buffer = os->postprocessing_buffer();
 836           view = buffer + view_start;
 837           if (output_offset != invalid_address && !must_decompress)
 838             {
 839               off_t sh_offset = shdr.get_sh_offset();
 840               if (!rm.empty() && rm.back().file_offset > sh_offset)
 841                 is_sorted = false;
 842               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 843                                                           view_size, view));
 844             }
 845         }
 846       else
 847         {
 848           if (output_offset == invalid_address)
 849             view = of->get_input_output_view(view_start, view_size);
 850           else
 851             {
 852               view = of->get_output_view(view_start, view_size);
 853               if (!must_decompress)
 854                 {
 855                   off_t sh_offset = shdr.get_sh_offset();
 856                   if (!rm.empty() && rm.back().file_offset > sh_offset)
 857                     is_sorted = false;
 858                   rm.push_back(File_read::Read_multiple_entry(sh_offset,
 859                                                               view_size, view));
 860                 }
 861             }
 862         }
 863
 864       if (must_decompress)
 865         {
 866           // Read and decompress the section.
 867           section_size_type len;
 868           const unsigned char* p = this->section_contents(i, &len, false);
 869           if (!decompress_input_section(p, len, view, view_size))
 870             this->error(_("could not decompress section %s"),
 871                         this->section_name(i).c_str());
 872         }
 873
 874       pvs->view = view;
 875       pvs->address = os->address();
 876       if (output_offset != invalid_address)
 877         pvs->address += output_offset;
 878       pvs->offset = view_start;
 879       pvs->view_size = view_size;
 880       pvs->is_input_output_view = output_offset == invalid_address;
 881       pvs->is_postprocessing_view = os->requires_postprocessing();
 882       pvs->is_ctors_reverse_view =
 883         (!parameters->options().relocatable()
 884          && view_size > size / 8
 885          && (strcmp(os->name(), ".init_array") == 0
 886              || strcmp(os->name(), ".fini_array") == 0)
 887          && layout->is_ctors_in_init_array(this, i));
 888     }
 889
 890   // Actually read the data.
 891   if (!rm.empty())
 892     {
 893       if (!is_sorted)
 894         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
 895       this->read_multiple(rm);
 896     }
 897 }
 898
 899 // Relocate section data.  VIEWS points to the section data as views
 900 // in the output file.
 901
 902 template<int size, bool big_endian>
 903 void
 904 Sized_relobj_file<size, big_endian>::do_relocate_sections(
 905     const Symbol_table* symtab,
 906     const Layout* layout,
 907     const unsigned char* pshdrs,
 908     Output_file* of,
 909     Views* pviews)
 910 {
 911   unsigned int shnum = this->shnum();
 912   Sized_target<size, big_endian>* target =
 913     parameters->sized_target<size, big_endian>();
 914
 915   const Output_sections& out_sections(this->output_sections());
 916   const std::vector<Address>& out_offsets(this->section_offsets());
 917
 918   Relocate_info<size, big_endian> relinfo;
 919   relinfo.symtab = symtab;
 920   relinfo.layout = layout;
 921   relinfo.object = this;
 922
 923   const unsigned char* p = pshdrs + This::shdr_size;
 924   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 925     {
 926       typename This::Shdr shdr(p);
 927
 928       unsigned int sh_type = shdr.get_sh_type();
 929       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 930         continue;
 931
 932       off_t sh_size = shdr.get_sh_size();
 933       if (sh_size == 0)
 934         continue;
 935
 936       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
 937       if (index >= this->shnum())
 938         {
 939           this->error(_("relocation section %u has bad info %u"),
 940                       i, index);
 941           continue;
 942         }
 943
 944       Output_section* os = out_sections[index];
 945       if (os == NULL)
 946         {
 947           // This relocation section is against a section which we
 948           // discarded.
 949           continue;
 950         }
 951       Address output_offset = out_offsets[index];
 952
 953       gold_assert((*pviews)[index].view != NULL);
 954       if (parameters->options().relocatable())
 955         gold_assert((*pviews)[i].view != NULL);
 956
 957       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 958         {
 959           gold_error(_("relocation section %u uses unexpected "
 960                        "symbol table %u"),
 961                      i, this->adjust_shndx(shdr.get_sh_link()));
 962           continue;
 963         }
 964
 965       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
 966                                                     sh_size, true, false);
 967
 968       unsigned int reloc_size;
 969       if (sh_type == elfcpp::SHT_REL)
 970         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 971       else
 972         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 973
 974       if (reloc_size != shdr.get_sh_entsize())
 975         {
 976           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
 977                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 978                      reloc_size);
 979           continue;
 980         }
 981
 982       size_t reloc_count = sh_size / reloc_size;
 983       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 984         {
 985           gold_error(_("reloc section %u size %lu uneven"),
 986                      i, static_cast<unsigned long>(sh_size));
 987           continue;
 988         }
 989
 990       gold_assert(output_offset != invalid_address
 991                   || this->relocs_must_follow_section_writes());
 992
 993       relinfo.reloc_shndx = i;
 994       relinfo.reloc_shdr = p;
 995       relinfo.data_shndx = index;
 996       relinfo.data_shdr = pshdrs + index * This::shdr_size;
 997       unsigned char* view = (*pviews)[index].view;
 998       Address address = (*pviews)[index].address;
 999       section_size_type view_size = (*pviews)[index].view_size;
1000
1001       Reloc_symbol_changes* reloc_map = NULL;
1002       if (this->uses_split_stack() && output_offset != invalid_address)
1003         {
1004           typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
1005           if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
1006             this->split_stack_adjust(symtab, pshdrs, sh_type, index,
1007                                      prelocs, reloc_count, view, view_size,
1008                                      &reloc_map);
1009         }
1010
1011       if (!parameters->options().relocatable())
1012         {
1013           target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
1014                                    output_offset == invalid_address,
1015                                    view, address, view_size, reloc_map);
1016           if (parameters->options().emit_relocs())
1017             {
1018               Relocatable_relocs* rr = this->relocatable_relocs(i);
1019               target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1020                                       os, output_offset, rr,
1021                                       view, address, view_size,
1022                                       (*pviews)[i].view,
1023                                       (*pviews)[i].view_size);
1024             }
1025           if (parameters->incremental())
1026             this->incremental_relocs_write(&relinfo, sh_type, prelocs,
1027                                            reloc_count, os, output_offset, of);
1028         }
1029       else
1030         {
1031           Relocatable_relocs* rr = this->relocatable_relocs(i);
1032           target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1033                                   os, output_offset, rr,
1034                                   view, address, view_size,
1035                                   (*pviews)[i].view,
1036                                   (*pviews)[i].view_size);
1037         }
1038     }
1039 }
1040
1041 // Write the incremental relocs.
1042
1043 template<int size, bool big_endian>
1044 void
1045 Sized_relobj_file<size, big_endian>::incremental_relocs_write(
1046     const Relocate_info<size, big_endian>* relinfo,
1047     unsigned int sh_type,
1048     const unsigned char* prelocs,
1049     size_t reloc_count,
1050     Output_section* output_section,
1051     Address output_offset,
1052     Output_file* of)
1053 {
1054   if (sh_type == elfcpp::SHT_REL)
1055     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1056         relinfo,
1057         prelocs,
1058         reloc_count,
1059         output_section,
1060         output_offset,
1061         of);
1062   else
1063     {
1064       gold_assert(sh_type == elfcpp::SHT_RELA);
1065       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1066           relinfo,
1067           prelocs,
1068           reloc_count,
1069           output_section,
1070           output_offset,
1071           of);
1072     }
1073 }
1074
1075 // Write the incremental relocs, templatized on the type of the
1076 // relocation section.
1077
1078 template<int size, bool big_endian>
1079 template<int sh_type>
1080 void
1081 Sized_relobj_file<size, big_endian>::incremental_relocs_write_reltype(
1082     const Relocate_info<size, big_endian>* relinfo,
1083     const unsigned char* prelocs,
1084     size_t reloc_count,
1085     Output_section* output_section,
1086     Address output_offset,
1087     Output_file* of)
1088 {
1089   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1090   const unsigned int reloc_size =
1091       Reloc_types<sh_type, size, big_endian>::reloc_size;
1092   const unsigned int sizeof_addr = size / 8;
1093   const unsigned int incr_reloc_size =
1094       Incremental_relocs_reader<size, big_endian>::reloc_size;
1095
1096   unsigned int out_shndx = output_section->out_shndx();
1097
1098   // Get a view for the .gnu_incremental_relocs section.
1099
1100   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1101   gold_assert(inputs != NULL);
1102   const off_t relocs_off = inputs->relocs_section()->offset();
1103   const off_t relocs_size = inputs->relocs_section()->data_size();
1104   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1105
1106   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1107     {
1108       Reloc reloc(prelocs);
1109
1110       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1111       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1112       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1113
1114       if (r_sym < this->local_symbol_count_)
1115         continue;
1116
1117       // Get the new offset--the location in the output section where
1118       // this relocation should be applied.
1119
1120       Address offset = reloc.get_r_offset();
1121       if (output_offset != invalid_address)
1122         offset += output_offset;
1123       else
1124         {
1125           section_offset_type sot_offset =
1126               convert_types<section_offset_type, Address>(offset);
1127           section_offset_type new_sot_offset =
1128               output_section->output_offset(relinfo->object,
1129                                             relinfo->data_shndx,
1130                                             sot_offset);
1131           gold_assert(new_sot_offset != -1);
1132           offset += new_sot_offset;
1133         }
1134
1135       // Get the addend.
1136       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1137       if (sh_type == elfcpp::SHT_RELA)
1138         addend =
1139             Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1140       else
1141         {
1142           // FIXME: Get the addend for SHT_REL.
1143           addend = 0;
1144         }
1145
1146       // Get the index of the output relocation.
1147
1148       unsigned int reloc_index =
1149           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1150
1151       // Write the relocation.
1152
1153       unsigned char* pov = view + reloc_index * incr_reloc_size;
1154       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1155       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1156       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1157       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1158       of->write_output_view(pov - view, incr_reloc_size, view);
1159     }
1160 }
1161
1162 // Create merge hash tables for the local symbols.  These are used to
1163 // speed up relocations.
1164
1165 template<int size, bool big_endian>
1166 void
1167 Sized_relobj_file<size, big_endian>::initialize_input_to_output_maps()
1168 {
1169   const unsigned int loccount = this->local_symbol_count_;
1170   for (unsigned int i = 1; i < loccount; ++i)
1171     {
1172       Symbol_value<size>& lv(this->local_values_[i]);
1173       lv.initialize_input_to_output_map(this);
1174     }
1175 }
1176
1177 // Free merge hash tables for the local symbols.
1178
1179 template<int size, bool big_endian>
1180 void
1181 Sized_relobj_file<size, big_endian>::free_input_to_output_maps()
1182 {
1183   const unsigned int loccount = this->local_symbol_count_;
1184   for (unsigned int i = 1; i < loccount; ++i)
1185     {
1186       Symbol_value<size>& lv(this->local_values_[i]);
1187       lv.free_input_to_output_map();
1188     }
1189 }
1190
1191 // If an object was compiled with -fsplit-stack, this is called to
1192 // check whether any relocations refer to functions defined in objects
1193 // which were not compiled with -fsplit-stack.  If they were, then we
1194 // need to apply some target-specific adjustments to request
1195 // additional stack space.
1196
1197 template<int size, bool big_endian>
1198 void
1199 Sized_relobj_file<size, big_endian>::split_stack_adjust(
1200     const Symbol_table* symtab,
1201     const unsigned char* pshdrs,
1202     unsigned int sh_type,
1203     unsigned int shndx,
1204     const unsigned char* prelocs,
1205     size_t reloc_count,
1206     unsigned char* view,
1207     section_size_type view_size,
1208     Reloc_symbol_changes** reloc_map)
1209 {
1210   if (sh_type == elfcpp::SHT_REL)
1211     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1212                                                       prelocs, reloc_count,
1213                                                       view, view_size,
1214                                                       reloc_map);
1215   else
1216     {
1217       gold_assert(sh_type == elfcpp::SHT_RELA);
1218       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1219                                                          prelocs, reloc_count,
1220                                                          view, view_size,
1221                                                          reloc_map);
1222     }
1223 }
1224
1225 // Adjust for -fsplit-stack, templatized on the type of the relocation
1226 // section.
1227
1228 template<int size, bool big_endian>
1229 template<int sh_type>
1230 void
1231 Sized_relobj_file<size, big_endian>::split_stack_adjust_reltype(
1232     const Symbol_table* symtab,
1233     const unsigned char* pshdrs,
1234     unsigned int shndx,
1235     const unsigned char* prelocs,
1236     size_t reloc_count,
1237     unsigned char* view,
1238     section_size_type view_size,
1239     Reloc_symbol_changes** reloc_map)
1240 {
1241   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1242   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1243
1244   size_t local_count = this->local_symbol_count();
1245
1246   std::vector<section_offset_type> non_split_refs;
1247
1248   const unsigned char* pr = prelocs;
1249   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1250     {
1251       Reltype reloc(pr);
1252
1253       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1254       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1255       if (r_sym < local_count)
1256         continue;
1257
1258       const Symbol* gsym = this->global_symbol(r_sym);
1259       gold_assert(gsym != NULL);
1260       if (gsym->is_forwarder())
1261         gsym = symtab->resolve_forwards(gsym);
1262
1263       // See if this relocation refers to a function defined in an
1264       // object compiled without -fsplit-stack.  Note that we don't
1265       // care about the type of relocation--this means that in some
1266       // cases we will ask for a large stack unnecessarily, but this
1267       // is not fatal.  FIXME: Some targets have symbols which are
1268       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1269       if (!gsym->is_undefined()
1270           && gsym->source() == Symbol::FROM_OBJECT
1271           && !gsym->object()->uses_split_stack())
1272         {
1273           unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info());
1274           if (parameters->target().is_call_to_non_split(gsym, r_type))
1275             {
1276               section_offset_type offset =
1277                 convert_to_section_size_type(reloc.get_r_offset());
1278               non_split_refs.push_back(offset);
1279             }
1280         }
1281     }
1282
1283   if (non_split_refs.empty())
1284     return;
1285
1286   // At this point, every entry in NON_SPLIT_REFS indicates a
1287   // relocation which refers to a function in an object compiled
1288   // without -fsplit-stack.  We now have to convert that list into a
1289   // set of offsets to functions.  First, we find all the functions.
1290
1291   Function_offsets function_offsets;
1292   this->find_functions(pshdrs, shndx, &function_offsets);
1293   if (function_offsets.empty())
1294     return;
1295
1296   // Now get a list of the function with references to non split-stack
1297   // code.
1298
1299   Function_offsets calls_non_split;
1300   for (std::vector<section_offset_type>::const_iterator p
1301          = non_split_refs.begin();
1302        p != non_split_refs.end();
1303        ++p)
1304     {
1305       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1306       if (low == function_offsets.end())
1307         --low;
1308       else if (low->first == *p)
1309         ;
1310       else if (low == function_offsets.begin())
1311         continue;
1312       else
1313         --low;
1314
1315       calls_non_split.insert(*low);
1316     }
1317   if (calls_non_split.empty())
1318     return;
1319
1320   // Now we have a set of functions to adjust.  The adjustments are
1321   // target specific.  Besides changing the output section view
1322   // however, it likes, the target may request a relocation change
1323   // from one global symbol name to another.
1324
1325   for (Function_offsets::const_iterator p = calls_non_split.begin();
1326        p != calls_non_split.end();
1327        ++p)
1328     {
1329       std::string from;
1330       std::string to;
1331       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1332                                            view, view_size, &from, &to);
1333       if (!from.empty())
1334         {
1335           gold_assert(!to.empty());
1336           Symbol* tosym = NULL;
1337
1338           // Find relocations in the relevant function which are for
1339           // FROM.
1340           pr = prelocs;
1341           for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1342             {
1343               Reltype reloc(pr);
1344
1345               typename elfcpp::Elf_types<size>::Elf_WXword r_info =
1346                 reloc.get_r_info();
1347               unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1348               if (r_sym < local_count)
1349                 continue;
1350
1351               section_offset_type offset =
1352                 convert_to_section_size_type(reloc.get_r_offset());
1353               if (offset < p->first
1354                   || (offset
1355                       >= (p->first
1356                           + static_cast<section_offset_type>(p->second))))
1357                 continue;
1358
1359               const Symbol* gsym = this->global_symbol(r_sym);
1360               if (from == gsym->name())
1361                 {
1362                   if (tosym == NULL)
1363                     {
1364                       tosym = symtab->lookup(to.c_str());
1365                       if (tosym == NULL)
1366                         {
1367                           this->error(_("could not convert call "
1368                                         "to '%s' to '%s'"),
1369                                       from.c_str(), to.c_str());
1370                           break;
1371                         }
1372                     }
1373
1374                   if (*reloc_map == NULL)
1375                     *reloc_map = new Reloc_symbol_changes(reloc_count);
1376                   (*reloc_map)->set(i, tosym);
1377                 }
1378             }
1379         }
1380     }
1381 }
1382
1383 // Find all the function in this object defined in section SHNDX.
1384 // Store their offsets in the section in FUNCTION_OFFSETS.
1385
1386 template<int size, bool big_endian>
1387 void
1388 Sized_relobj_file<size, big_endian>::find_functions(
1389     const unsigned char* pshdrs,
1390     unsigned int shndx,
1391     Sized_relobj_file<size, big_endian>::Function_offsets* function_offsets)
1392 {
1393   // We need to read the symbols to find the functions.  If we wanted
1394   // to, we could cache reading the symbols across all sections in the
1395   // object.
1396   const unsigned int symtab_shndx = this->symtab_shndx_;
1397   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1398   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1399
1400   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1401     symtabshdr.get_sh_size();
1402   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1403                                               sh_size, true, true);
1404
1405   const int sym_size = This::sym_size;
1406   const unsigned int symcount = sh_size / sym_size;
1407   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1408     {
1409       typename elfcpp::Sym<size, big_endian> isym(psyms);
1410
1411       // FIXME: Some targets can have functions which do not have type
1412       // STT_FUNC, e.g., STT_ARM_TFUNC.
1413       if (isym.get_st_type() != elfcpp::STT_FUNC
1414           || isym.get_st_size() == 0)
1415         continue;
1416
1417       bool is_ordinary;
1418       unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1419                                                       &is_ordinary);
1420       if (!is_ordinary || sym_shndx != shndx)
1421         continue;
1422
1423       section_offset_type value =
1424         convert_to_section_size_type(isym.get_st_value());
1425       section_size_type fnsize =
1426         convert_to_section_size_type(isym.get_st_size());
1427
1428       (*function_offsets)[value] = fnsize;
1429     }
1430 }
1431
1432 // Reverse the words in a section.  Used for .ctors sections mapped to
1433 // .init_array sections.  See ctors_sections_in_init_array in
1434 // layout.cc.
1435
1436 template<int size, bool big_endian>
1437 void
1438 Sized_relobj_file<size, big_endian>::reverse_words(unsigned char* view,
1439                                                    section_size_type view_size)
1440 {
1441   typedef typename elfcpp::Swap<size, big_endian>::Valtype Valtype;
1442   Valtype* vview = reinterpret_cast<Valtype*>(view);
1443   section_size_type vview_size = view_size / (size / 8);
1444   for (section_size_type i = 0; i < vview_size / 2; ++i)
1445     {
1446       Valtype tmp = vview[i];
1447       vview[i] = vview[vview_size - 1 - i];
1448       vview[vview_size - 1 - i] = tmp;
1449     }
1450 }
1451
1452 // Class Merged_symbol_value.
1453
1454 template<int size>
1455 void
1456 Merged_symbol_value<size>::initialize_input_to_output_map(
1457     const Relobj* object,
1458     unsigned int input_shndx)
1459 {
1460   Object_merge_map* map = object->merge_map();
1461   map->initialize_input_to_output_map<size>(input_shndx,
1462                                             this->output_start_address_,
1463                                             &this->output_addresses_);
1464 }
1465
1466 // Get the output value corresponding to an input offset if we
1467 // couldn't find it in the hash table.
1468
1469 template<int size>
1470 typename elfcpp::Elf_types<size>::Elf_Addr
1471 Merged_symbol_value<size>::value_from_output_section(
1472     const Relobj* object,
1473     unsigned int input_shndx,
1474     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1475 {
1476   section_offset_type output_offset;
1477   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
1478                                                       input_offset,
1479                                                       &output_offset);
1480
1481   // If this assertion fails, it means that some relocation was
1482   // against a portion of an input merge section which we didn't map
1483   // to the output file and we didn't explicitly discard.  We should
1484   // always map all portions of input merge sections.
1485   gold_assert(found);
1486
1487   if (output_offset == -1)
1488     return 0;
1489   else
1490     return this->output_start_address_ + output_offset;
1491 }
1492
1493 // Track_relocs methods.
1494
1495 // Initialize the class to track the relocs.  This gets the object,
1496 // the reloc section index, and the type of the relocs.  This returns
1497 // false if something goes wrong.
1498
1499 template<int size, bool big_endian>
1500 bool
1501 Track_relocs<size, big_endian>::initialize(
1502     Object* object,
1503     unsigned int reloc_shndx,
1504     unsigned int reloc_type)
1505 {
1506   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1507   // section for the .eh_frame section.  We can't handle that case.
1508   if (reloc_shndx == -1U)
1509     return false;
1510
1511   // If RELOC_SHNDX is 0, there is no reloc section.
1512   if (reloc_shndx == 0)
1513     return true;
1514
1515   // Get the contents of the reloc section.
1516   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1517
1518   if (reloc_type == elfcpp::SHT_REL)
1519     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1520   else if (reloc_type == elfcpp::SHT_RELA)
1521     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1522   else
1523     gold_unreachable();
1524
1525   if (this->len_ % this->reloc_size_ != 0)
1526     {
1527       object->error(_("reloc section size %zu is not a multiple of "
1528                       "reloc size %d\n"),
1529                     static_cast<size_t>(this->len_),
1530                     this->reloc_size_);
1531       return false;
1532     }
1533
1534   return true;
1535 }
1536
1537 // Return the offset of the next reloc, or -1 if there isn't one.
1538
1539 template<int size, bool big_endian>
1540 off_t
1541 Track_relocs<size, big_endian>::next_offset() const
1542 {
1543   if (this->pos_ >= this->len_)
1544     return -1;
1545
1546   // Rel and Rela start out the same, so we can always use Rel to find
1547   // the r_offset value.
1548   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1549   return rel.get_r_offset();
1550 }
1551
1552 // Return the index of the symbol referenced by the next reloc, or -1U
1553 // if there aren't any more relocs.
1554
1555 template<int size, bool big_endian>
1556 unsigned int
1557 Track_relocs<size, big_endian>::next_symndx() const
1558 {
1559   if (this->pos_ >= this->len_)
1560     return -1U;
1561
1562   // Rel and Rela start out the same, so we can use Rel to find the
1563   // symbol index.
1564   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1565   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1566 }
1567
1568 // Return the addend of the next reloc, or 0 if there isn't one.
1569
1570 template<int size, bool big_endian>
1571 uint64_t
1572 Track_relocs<size, big_endian>::next_addend() const
1573 {
1574   if (this->pos_ >= this->len_)
1575     return 0;
1576   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1577     return 0;
1578   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1579   return rela.get_r_addend();
1580 }
1581
1582 // Advance to the next reloc whose r_offset is greater than or equal
1583 // to OFFSET.  Return the number of relocs we skip.
1584
1585 template<int size, bool big_endian>
1586 int
1587 Track_relocs<size, big_endian>::advance(off_t offset)
1588 {
1589   int ret = 0;
1590   while (this->pos_ < this->len_)
1591     {
1592       // Rel and Rela start out the same, so we can always use Rel to
1593       // find the r_offset value.
1594       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1595       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1596         break;
1597       ++ret;
1598       this->pos_ += this->reloc_size_;
1599     }
1600   return ret;
1601 }
1602
1603 // Instantiate the templates we need.
1604
1605 #ifdef HAVE_TARGET_32_LITTLE
1606 template
1607 void
1608 Sized_relobj_file<32, false>::do_read_relocs(Read_relocs_data* rd);
1609 #endif
1610
1611 #ifdef HAVE_TARGET_32_BIG
1612 template
1613 void
1614 Sized_relobj_file<32, true>::do_read_relocs(Read_relocs_data* rd);
1615 #endif
1616
1617 #ifdef HAVE_TARGET_64_LITTLE
1618 template
1619 void
1620 Sized_relobj_file<64, false>::do_read_relocs(Read_relocs_data* rd);
1621 #endif
1622
1623 #ifdef HAVE_TARGET_64_BIG
1624 template
1625 void
1626 Sized_relobj_file<64, true>::do_read_relocs(Read_relocs_data* rd);
1627 #endif
1628
1629 #ifdef HAVE_TARGET_32_LITTLE
1630 template
1631 void
1632 Sized_relobj_file<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1633                                                    Layout* layout,
1634                                                    Read_relocs_data* rd);
1635 #endif
1636
1637 #ifdef HAVE_TARGET_32_BIG
1638 template
1639 void
1640 Sized_relobj_file<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1641                                                   Layout* layout,
1642                                                   Read_relocs_data* rd);
1643 #endif
1644
1645 #ifdef HAVE_TARGET_64_LITTLE
1646 template
1647 void
1648 Sized_relobj_file<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1649                                                    Layout* layout,
1650                                                    Read_relocs_data* rd);
1651 #endif
1652
1653 #ifdef HAVE_TARGET_64_BIG
1654 template
1655 void
1656 Sized_relobj_file<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1657                                                   Layout* layout,
1658                                                   Read_relocs_data* rd);
1659 #endif
1660
1661 #ifdef HAVE_TARGET_32_LITTLE
1662 template
1663 void
1664 Sized_relobj_file<32, false>::do_scan_relocs(Symbol_table* symtab,
1665                                              Layout* layout,
1666                                              Read_relocs_data* rd);
1667 #endif
1668
1669 #ifdef HAVE_TARGET_32_BIG
1670 template
1671 void
1672 Sized_relobj_file<32, true>::do_scan_relocs(Symbol_table* symtab,
1673                                             Layout* layout,
1674                                             Read_relocs_data* rd);
1675 #endif
1676
1677 #ifdef HAVE_TARGET_64_LITTLE
1678 template
1679 void
1680 Sized_relobj_file<64, false>::do_scan_relocs(Symbol_table* symtab,
1681                                              Layout* layout,
1682                                              Read_relocs_data* rd);
1683 #endif
1684
1685 #ifdef HAVE_TARGET_64_BIG
1686 template
1687 void
1688 Sized_relobj_file<64, true>::do_scan_relocs(Symbol_table* symtab,
1689                                             Layout* layout,
1690                                             Read_relocs_data* rd);
1691 #endif
1692
1693 #ifdef HAVE_TARGET_32_LITTLE
1694 template
1695 void
1696 Sized_relobj_file<32, false>::do_relocate(const Symbol_table* symtab,
1697                                           const Layout* layout,
1698                                           Output_file* of);
1699 #endif
1700
1701 #ifdef HAVE_TARGET_32_BIG
1702 template
1703 void
1704 Sized_relobj_file<32, true>::do_relocate(const Symbol_table* symtab,
1705                                          const Layout* layout,
1706                                          Output_file* of);
1707 #endif
1708
1709 #ifdef HAVE_TARGET_64_LITTLE
1710 template
1711 void
1712 Sized_relobj_file<64, false>::do_relocate(const Symbol_table* symtab,
1713                                           const Layout* layout,
1714                                           Output_file* of);
1715 #endif
1716
1717 #ifdef HAVE_TARGET_64_BIG
1718 template
1719 void
1720 Sized_relobj_file<64, true>::do_relocate(const Symbol_table* symtab,
1721                                          const Layout* layout,
1722                                          Output_file* of);
1723 #endif
1724
1725 #ifdef HAVE_TARGET_32_LITTLE
1726 template
1727 void
1728 Sized_relobj_file<32, false>::do_relocate_sections(
1729     const Symbol_table* symtab,
1730     const Layout* layout,
1731     const unsigned char* pshdrs,
1732     Output_file* of,
1733     Views* pviews);
1734 #endif
1735
1736 #ifdef HAVE_TARGET_32_BIG
1737 template
1738 void
1739 Sized_relobj_file<32, true>::do_relocate_sections(
1740     const Symbol_table* symtab,
1741     const Layout* layout,
1742     const unsigned char* pshdrs,
1743     Output_file* of,
1744     Views* pviews);
1745 #endif
1746
1747 #ifdef HAVE_TARGET_64_LITTLE
1748 template
1749 void
1750 Sized_relobj_file<64, false>::do_relocate_sections(
1751     const Symbol_table* symtab,
1752     const Layout* layout,
1753     const unsigned char* pshdrs,
1754     Output_file* of,
1755     Views* pviews);
1756 #endif
1757
1758 #ifdef HAVE_TARGET_64_BIG
1759 template
1760 void
1761 Sized_relobj_file<64, true>::do_relocate_sections(
1762     const Symbol_table* symtab,
1763     const Layout* layout,
1764     const unsigned char* pshdrs,
1765     Output_file* of,
1766     Views* pviews);
1767 #endif
1768
1769 #ifdef HAVE_TARGET_32_LITTLE
1770 template
1771 void
1772 Sized_relobj_file<32, false>::initialize_input_to_output_maps();
1773
1774 template
1775 void
1776 Sized_relobj_file<32, false>::free_input_to_output_maps();
1777 #endif
1778
1779 #ifdef HAVE_TARGET_32_BIG
1780 template
1781 void
1782 Sized_relobj_file<32, true>::initialize_input_to_output_maps();
1783
1784 template
1785 void
1786 Sized_relobj_file<32, true>::free_input_to_output_maps();
1787 #endif
1788
1789 #ifdef HAVE_TARGET_64_LITTLE
1790 template
1791 void
1792 Sized_relobj_file<64, false>::initialize_input_to_output_maps();
1793
1794 template
1795 void
1796 Sized_relobj_file<64, false>::free_input_to_output_maps();
1797 #endif
1798
1799 #ifdef HAVE_TARGET_64_BIG
1800 template
1801 void
1802 Sized_relobj_file<64, true>::initialize_input_to_output_maps();
1803
1804 template
1805 void
1806 Sized_relobj_file<64, true>::free_input_to_output_maps();
1807 #endif
1808
1809 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1810 template
1811 class Merged_symbol_value<32>;
1812 #endif
1813
1814 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1815 template
1816 class Merged_symbol_value<64>;
1817 #endif
1818
1819 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1820 template
1821 class Symbol_value<32>;
1822 #endif
1823
1824 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1825 template
1826 class Symbol_value<64>;
1827 #endif
1828
1829 #ifdef HAVE_TARGET_32_LITTLE
1830 template
1831 class Track_relocs<32, false>;
1832 #endif
1833
1834 #ifdef HAVE_TARGET_32_BIG
1835 template
1836 class Track_relocs<32, true>;
1837 #endif
1838
1839 #ifdef HAVE_TARGET_64_LITTLE
1840 template
1841 class Track_relocs<64, false>;
1842 #endif
1843
1844 #ifdef HAVE_TARGET_64_BIG
1845 template
1846 class Track_relocs<64, true>;
1847 #endif
1848
1849 } // End namespace gold.