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(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_postprocessing_view)
 682             {
 683               if (views[i].is_input_output_view)
 684                 of->write_input_output_view(views[i].offset,
 685                                             views[i].view_size,
 686                                             views[i].view);
 687               else
 688                 of->write_output_view(views[i].offset, views[i].view_size,
 689                                       views[i].view);
 690             }
 691         }
 692     }
 693
 694   // Write out the local symbols.
 695   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
 696                             layout->symtab_xindex(), layout->dynsym_xindex(),
 697                             layout->symtab_section_offset());
 698 }
 699
 700 // Sort a Read_multiple vector by file offset.
 701 struct Read_multiple_compare
 702 {
 703   inline bool
 704   operator()(const File_read::Read_multiple_entry& rme1,
 705              const File_read::Read_multiple_entry& rme2) const
 706   { return rme1.file_offset < rme2.file_offset; }
 707 };
 708
 709 // Write section data to the output file.  PSHDRS points to the
 710 // section headers.  Record the views in *PVIEWS for use when
 711 // relocating.
 712
 713 template<int size, bool big_endian>
 714 void
 715 Sized_relobj_file<size, big_endian>::write_sections(const unsigned char* pshdrs,
 716                                                     Output_file* of,
 717                                                     Views* pviews)
 718 {
 719   unsigned int shnum = this->shnum();
 720   const Output_sections& out_sections(this->output_sections());
 721   const std::vector<Address>& out_offsets(this->section_offsets());
 722
 723   File_read::Read_multiple rm;
 724   bool is_sorted = true;
 725
 726   const unsigned char* p = pshdrs + This::shdr_size;
 727   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 728     {
 729       View_size* pvs = &(*pviews)[i];
 730
 731       pvs->view = NULL;
 732
 733       const Output_section* os = out_sections[i];
 734       if (os == NULL)
 735         continue;
 736       Address output_offset = out_offsets[i];
 737
 738       typename This::Shdr shdr(p);
 739
 740       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
 741         continue;
 742
 743       if ((parameters->options().relocatable()
 744            || parameters->options().emit_relocs())
 745           && (shdr.get_sh_type() == elfcpp::SHT_REL
 746               || shdr.get_sh_type() == elfcpp::SHT_RELA)
 747           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 748         {
 749           // This is a reloc section in a relocatable link or when
 750           // emitting relocs.  We don't need to read the input file.
 751           // The size and file offset are stored in the
 752           // Relocatable_relocs structure.
 753           Relocatable_relocs* rr = this->relocatable_relocs(i);
 754           gold_assert(rr != NULL);
 755           Output_data* posd = rr->output_data();
 756           gold_assert(posd != NULL);
 757
 758           pvs->offset = posd->offset();
 759           pvs->view_size = posd->data_size();
 760           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
 761           pvs->address = posd->address();
 762           pvs->is_input_output_view = false;
 763           pvs->is_postprocessing_view = false;
 764
 765           continue;
 766         }
 767
 768       // In the normal case, this input section is simply mapped to
 769       // the output section at offset OUTPUT_OFFSET.
 770
 771       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
 772       // handled specially--e.g., a .eh_frame section.  The relocation
 773       // routines need to check for each reloc where it should be
 774       // applied.  For this case, we need an input/output view for the
 775       // entire contents of the section in the output file.  We don't
 776       // want to copy the contents of the input section to the output
 777       // section; the output section contents were already written,
 778       // and we waited for them in Relocate_task::is_runnable because
 779       // relocs_must_follow_section_writes is set for the object.
 780
 781       // Regardless of which of the above cases is true, we have to
 782       // check requires_postprocessing of the output section.  If that
 783       // is false, then we work with views of the output file
 784       // directly.  If it is true, then we work with a separate
 785       // buffer, and the output section is responsible for writing the
 786       // final data to the output file.
 787
 788       off_t output_section_offset;
 789       Address output_section_size;
 790       if (!os->requires_postprocessing())
 791         {
 792           output_section_offset = os->offset();
 793           output_section_size = convert_types<Address, off_t>(os->data_size());
 794         }
 795       else
 796         {
 797           output_section_offset = 0;
 798           output_section_size =
 799               convert_types<Address, off_t>(os->postprocessing_buffer_size());
 800         }
 801
 802       off_t view_start;
 803       section_size_type view_size;
 804       bool must_decompress = false;
 805       if (output_offset != invalid_address)
 806         {
 807           view_start = output_section_offset + output_offset;
 808           view_size = convert_to_section_size_type(shdr.get_sh_size());
 809           section_size_type uncompressed_size;
 810           if (this->section_is_compressed(i, &uncompressed_size))
 811             {
 812               view_size = uncompressed_size;
 813               must_decompress = true;
 814             }
 815         }
 816       else
 817         {
 818           view_start = output_section_offset;
 819           view_size = convert_to_section_size_type(output_section_size);
 820         }
 821
 822       if (view_size == 0)
 823         continue;
 824
 825       gold_assert(output_offset == invalid_address
 826                   || output_offset + view_size <= output_section_size);
 827
 828       unsigned char* view;
 829       if (os->requires_postprocessing())
 830         {
 831           unsigned char* buffer = os->postprocessing_buffer();
 832           view = buffer + view_start;
 833           if (output_offset != invalid_address && !must_decompress)
 834             {
 835               off_t sh_offset = shdr.get_sh_offset();
 836               if (!rm.empty() && rm.back().file_offset > sh_offset)
 837                 is_sorted = false;
 838               rm.push_back(File_read::Read_multiple_entry(sh_offset,
 839                                                           view_size, view));
 840             }
 841         }
 842       else
 843         {
 844           if (output_offset == invalid_address)
 845             view = of->get_input_output_view(view_start, view_size);
 846           else
 847             {
 848               view = of->get_output_view(view_start, view_size);
 849               if (!must_decompress)
 850                 {
 851                   off_t sh_offset = shdr.get_sh_offset();
 852                   if (!rm.empty() && rm.back().file_offset > sh_offset)
 853                     is_sorted = false;
 854                   rm.push_back(File_read::Read_multiple_entry(sh_offset,
 855                                                               view_size, view));
 856                 }
 857             }
 858         }
 859
 860       if (must_decompress)
 861         {
 862           // Read and decompress the section.
 863           section_size_type len;
 864           const unsigned char* p = this->section_contents(i, &len, false);
 865           if (!decompress_input_section(p, len, view, view_size))
 866             this->error(_("could not decompress section %s"),
 867                         this->section_name(i).c_str());
 868         }
 869
 870       pvs->view = view;
 871       pvs->address = os->address();
 872       if (output_offset != invalid_address)
 873         pvs->address += output_offset;
 874       pvs->offset = view_start;
 875       pvs->view_size = view_size;
 876       pvs->is_input_output_view = output_offset == invalid_address;
 877       pvs->is_postprocessing_view = os->requires_postprocessing();
 878     }
 879
 880   // Actually read the data.
 881   if (!rm.empty())
 882     {
 883       if (!is_sorted)
 884         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
 885       this->read_multiple(rm);
 886     }
 887 }
 888
 889 // Relocate section data.  VIEWS points to the section data as views
 890 // in the output file.
 891
 892 template<int size, bool big_endian>
 893 void
 894 Sized_relobj_file<size, big_endian>::do_relocate_sections(
 895     const Symbol_table* symtab,
 896     const Layout* layout,
 897     const unsigned char* pshdrs,
 898     Output_file* of,
 899     Views* pviews)
 900 {
 901   unsigned int shnum = this->shnum();
 902   Sized_target<size, big_endian>* target =
 903     parameters->sized_target<size, big_endian>();
 904
 905   const Output_sections& out_sections(this->output_sections());
 906   const std::vector<Address>& out_offsets(this->section_offsets());
 907
 908   Relocate_info<size, big_endian> relinfo;
 909   relinfo.symtab = symtab;
 910   relinfo.layout = layout;
 911   relinfo.object = this;
 912
 913   const unsigned char* p = pshdrs + This::shdr_size;
 914   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
 915     {
 916       typename This::Shdr shdr(p);
 917
 918       unsigned int sh_type = shdr.get_sh_type();
 919       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
 920         continue;
 921
 922       off_t sh_size = shdr.get_sh_size();
 923       if (sh_size == 0)
 924         continue;
 925
 926       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
 927       if (index >= this->shnum())
 928         {
 929           this->error(_("relocation section %u has bad info %u"),
 930                       i, index);
 931           continue;
 932         }
 933
 934       Output_section* os = out_sections[index];
 935       if (os == NULL)
 936         {
 937           // This relocation section is against a section which we
 938           // discarded.
 939           continue;
 940         }
 941       Address output_offset = out_offsets[index];
 942
 943       gold_assert((*pviews)[index].view != NULL);
 944       if (parameters->options().relocatable())
 945         gold_assert((*pviews)[i].view != NULL);
 946
 947       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
 948         {
 949           gold_error(_("relocation section %u uses unexpected "
 950                        "symbol table %u"),
 951                      i, this->adjust_shndx(shdr.get_sh_link()));
 952           continue;
 953         }
 954
 955       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
 956                                                     sh_size, true, false);
 957
 958       unsigned int reloc_size;
 959       if (sh_type == elfcpp::SHT_REL)
 960         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
 961       else
 962         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 963
 964       if (reloc_size != shdr.get_sh_entsize())
 965         {
 966           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
 967                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
 968                      reloc_size);
 969           continue;
 970         }
 971
 972       size_t reloc_count = sh_size / reloc_size;
 973       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
 974         {
 975           gold_error(_("reloc section %u size %lu uneven"),
 976                      i, static_cast<unsigned long>(sh_size));
 977           continue;
 978         }
 979
 980       gold_assert(output_offset != invalid_address
 981                   || this->relocs_must_follow_section_writes());
 982
 983       relinfo.reloc_shndx = i;
 984       relinfo.reloc_shdr = p;
 985       relinfo.data_shndx = index;
 986       relinfo.data_shdr = pshdrs + index * This::shdr_size;
 987       unsigned char* view = (*pviews)[index].view;
 988       Address address = (*pviews)[index].address;
 989       section_size_type view_size = (*pviews)[index].view_size;
 990
 991       Reloc_symbol_changes* reloc_map = NULL;
 992       if (this->uses_split_stack() && output_offset != invalid_address)
 993         {
 994           typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
 995           if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
 996             this->split_stack_adjust(symtab, pshdrs, sh_type, index,
 997                                      prelocs, reloc_count, view, view_size,
 998                                      &reloc_map);
 999         }
1000
1001       if (!parameters->options().relocatable())
1002         {
1003           target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
1004                                    output_offset == invalid_address,
1005                                    view, address, view_size, reloc_map);
1006           if (parameters->options().emit_relocs())
1007             this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
1008                               os, output_offset, view, address, view_size,
1009                               (*pviews)[i].view, (*pviews)[i].view_size);
1010           if (parameters->incremental())
1011             this->incremental_relocs_write(&relinfo, sh_type, prelocs,
1012                                            reloc_count, os, output_offset, of);
1013         }
1014       else
1015         {
1016           Relocatable_relocs* rr = this->relocatable_relocs(i);
1017           target->relocate_for_relocatable(&relinfo, sh_type, prelocs,
1018                                            reloc_count, os, output_offset, rr,
1019                                            view, address, view_size,
1020                                            (*pviews)[i].view,
1021                                            (*pviews)[i].view_size);
1022         }
1023     }
1024 }
1025
1026 // Emit the relocs for --emit-relocs.
1027
1028 template<int size, bool big_endian>
1029 void
1030 Sized_relobj_file<size, big_endian>::emit_relocs(
1031     const Relocate_info<size, big_endian>* relinfo,
1032     unsigned int i,
1033     unsigned int sh_type,
1034     const unsigned char* prelocs,
1035     size_t reloc_count,
1036     Output_section* output_section,
1037     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
1038     unsigned char* view,
1039     typename elfcpp::Elf_types<size>::Elf_Addr address,
1040     section_size_type view_size,
1041     unsigned char* reloc_view,
1042     section_size_type reloc_view_size)
1043 {
1044   if (sh_type == elfcpp::SHT_REL)
1045     this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
1046                                                reloc_count, output_section,
1047                                                offset_in_output_section,
1048                                                view, address, view_size,
1049                                                reloc_view, reloc_view_size);
1050   else
1051     {
1052       gold_assert(sh_type == elfcpp::SHT_RELA);
1053       this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
1054                                                   reloc_count, output_section,
1055                                                   offset_in_output_section,
1056                                                   view, address, view_size,
1057                                                   reloc_view, reloc_view_size);
1058     }
1059 }
1060
1061 // Emit the relocs for --emit-relocs, templatized on the type of the
1062 // relocation section.
1063
1064 template<int size, bool big_endian>
1065 template<int sh_type>
1066 void
1067 Sized_relobj_file<size, big_endian>::emit_relocs_reltype(
1068     const Relocate_info<size, big_endian>* relinfo,
1069     unsigned int i,
1070     const unsigned char* prelocs,
1071     size_t reloc_count,
1072     Output_section* output_section,
1073     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
1074     unsigned char* view,
1075     typename elfcpp::Elf_types<size>::Elf_Addr address,
1076     section_size_type view_size,
1077     unsigned char* reloc_view,
1078     section_size_type reloc_view_size)
1079 {
1080   const Relocatable_relocs* rr = this->relocatable_relocs(i);
1081   relocate_for_relocatable<size, big_endian, sh_type>(
1082     relinfo,
1083     prelocs,
1084     reloc_count,
1085     output_section,
1086     offset_in_output_section,
1087     rr,
1088     view,
1089     address,
1090     view_size,
1091     reloc_view,
1092     reloc_view_size);
1093 }
1094
1095 // Write the incremental relocs.
1096
1097 template<int size, bool big_endian>
1098 void
1099 Sized_relobj_file<size, big_endian>::incremental_relocs_write(
1100     const Relocate_info<size, big_endian>* relinfo,
1101     unsigned int sh_type,
1102     const unsigned char* prelocs,
1103     size_t reloc_count,
1104     Output_section* output_section,
1105     Address output_offset,
1106     Output_file* of)
1107 {
1108   if (sh_type == elfcpp::SHT_REL)
1109     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1110         relinfo,
1111         prelocs,
1112         reloc_count,
1113         output_section,
1114         output_offset,
1115         of);
1116   else
1117     {
1118       gold_assert(sh_type == elfcpp::SHT_RELA);
1119       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1120           relinfo,
1121           prelocs,
1122           reloc_count,
1123           output_section,
1124           output_offset,
1125           of);
1126     }
1127 }
1128
1129 // Write the incremental relocs, templatized on the type of the
1130 // relocation section.
1131
1132 template<int size, bool big_endian>
1133 template<int sh_type>
1134 void
1135 Sized_relobj_file<size, big_endian>::incremental_relocs_write_reltype(
1136     const Relocate_info<size, big_endian>* relinfo,
1137     const unsigned char* prelocs,
1138     size_t reloc_count,
1139     Output_section* output_section,
1140     Address output_offset,
1141     Output_file* of)
1142 {
1143   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1144   const unsigned int reloc_size =
1145       Reloc_types<sh_type, size, big_endian>::reloc_size;
1146   const unsigned int sizeof_addr = size / 8;
1147   const unsigned int incr_reloc_size =
1148       Incremental_relocs_reader<size, big_endian>::reloc_size;
1149
1150   unsigned int out_shndx = output_section->out_shndx();
1151
1152   // Get a view for the .gnu_incremental_relocs section.
1153
1154   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1155   gold_assert(inputs != NULL);
1156   const off_t relocs_off = inputs->relocs_section()->offset();
1157   const off_t relocs_size = inputs->relocs_section()->data_size();
1158   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1159
1160   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1161     {
1162       Reloc reloc(prelocs);
1163
1164       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1165       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1166       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1167
1168       if (r_sym < this->local_symbol_count_)
1169         continue;
1170
1171       // Get the new offset--the location in the output section where
1172       // this relocation should be applied.
1173
1174       Address offset = reloc.get_r_offset();
1175       if (output_offset != invalid_address)
1176         offset += output_offset;
1177       else
1178         {
1179           section_offset_type sot_offset =
1180               convert_types<section_offset_type, Address>(offset);
1181           section_offset_type new_sot_offset =
1182               output_section->output_offset(relinfo->object,
1183                                             relinfo->data_shndx,
1184                                             sot_offset);
1185           gold_assert(new_sot_offset != -1);
1186           offset += new_sot_offset;
1187         }
1188
1189       // Get the addend.
1190       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1191       if (sh_type == elfcpp::SHT_RELA)
1192         addend =
1193             Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1194       else
1195         {
1196           // FIXME: Get the addend for SHT_REL.
1197           addend = 0;
1198         }
1199
1200       // Get the index of the output relocation.
1201
1202       unsigned int reloc_index =
1203           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1204
1205       // Write the relocation.
1206
1207       unsigned char* pov = view + reloc_index * incr_reloc_size;
1208       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1209       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1210       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1211       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1212       of->write_output_view(pov - view, incr_reloc_size, view);
1213     }
1214 }
1215
1216 // Create merge hash tables for the local symbols.  These are used to
1217 // speed up relocations.
1218
1219 template<int size, bool big_endian>
1220 void
1221 Sized_relobj_file<size, big_endian>::initialize_input_to_output_maps()
1222 {
1223   const unsigned int loccount = this->local_symbol_count_;
1224   for (unsigned int i = 1; i < loccount; ++i)
1225     {
1226       Symbol_value<size>& lv(this->local_values_[i]);
1227       lv.initialize_input_to_output_map(this);
1228     }
1229 }
1230
1231 // Free merge hash tables for the local symbols.
1232
1233 template<int size, bool big_endian>
1234 void
1235 Sized_relobj_file<size, big_endian>::free_input_to_output_maps()
1236 {
1237   const unsigned int loccount = this->local_symbol_count_;
1238   for (unsigned int i = 1; i < loccount; ++i)
1239     {
1240       Symbol_value<size>& lv(this->local_values_[i]);
1241       lv.free_input_to_output_map();
1242     }
1243 }
1244
1245 // If an object was compiled with -fsplit-stack, this is called to
1246 // check whether any relocations refer to functions defined in objects
1247 // which were not compiled with -fsplit-stack.  If they were, then we
1248 // need to apply some target-specific adjustments to request
1249 // additional stack space.
1250
1251 template<int size, bool big_endian>
1252 void
1253 Sized_relobj_file<size, big_endian>::split_stack_adjust(
1254     const Symbol_table* symtab,
1255     const unsigned char* pshdrs,
1256     unsigned int sh_type,
1257     unsigned int shndx,
1258     const unsigned char* prelocs,
1259     size_t reloc_count,
1260     unsigned char* view,
1261     section_size_type view_size,
1262     Reloc_symbol_changes** reloc_map)
1263 {
1264   if (sh_type == elfcpp::SHT_REL)
1265     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1266                                                       prelocs, reloc_count,
1267                                                       view, view_size,
1268                                                       reloc_map);
1269   else
1270     {
1271       gold_assert(sh_type == elfcpp::SHT_RELA);
1272       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1273                                                          prelocs, reloc_count,
1274                                                          view, view_size,
1275                                                          reloc_map);
1276     }
1277 }
1278
1279 // Adjust for -fsplit-stack, templatized on the type of the relocation
1280 // section.
1281
1282 template<int size, bool big_endian>
1283 template<int sh_type>
1284 void
1285 Sized_relobj_file<size, big_endian>::split_stack_adjust_reltype(
1286     const Symbol_table* symtab,
1287     const unsigned char* pshdrs,
1288     unsigned int shndx,
1289     const unsigned char* prelocs,
1290     size_t reloc_count,
1291     unsigned char* view,
1292     section_size_type view_size,
1293     Reloc_symbol_changes** reloc_map)
1294 {
1295   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1296   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1297
1298   size_t local_count = this->local_symbol_count();
1299
1300   std::vector<section_offset_type> non_split_refs;
1301
1302   const unsigned char* pr = prelocs;
1303   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1304     {
1305       Reltype reloc(pr);
1306
1307       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1308       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1309       if (r_sym < local_count)
1310         continue;
1311
1312       const Symbol* gsym = this->global_symbol(r_sym);
1313       gold_assert(gsym != NULL);
1314       if (gsym->is_forwarder())
1315         gsym = symtab->resolve_forwards(gsym);
1316
1317       // See if this relocation refers to a function defined in an
1318       // object compiled without -fsplit-stack.  Note that we don't
1319       // care about the type of relocation--this means that in some
1320       // cases we will ask for a large stack unnecessarily, but this
1321       // is not fatal.  FIXME: Some targets have symbols which are
1322       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1323       if (!gsym->is_undefined()
1324           && gsym->source() == Symbol::FROM_OBJECT
1325           && !gsym->object()->uses_split_stack())
1326         {
1327           unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info());
1328           if (parameters->target().is_call_to_non_split(gsym, r_type))
1329             {
1330               section_offset_type offset =
1331                 convert_to_section_size_type(reloc.get_r_offset());
1332               non_split_refs.push_back(offset);
1333             }
1334         }
1335     }
1336
1337   if (non_split_refs.empty())
1338     return;
1339
1340   // At this point, every entry in NON_SPLIT_REFS indicates a
1341   // relocation which refers to a function in an object compiled
1342   // without -fsplit-stack.  We now have to convert that list into a
1343   // set of offsets to functions.  First, we find all the functions.
1344
1345   Function_offsets function_offsets;
1346   this->find_functions(pshdrs, shndx, &function_offsets);
1347   if (function_offsets.empty())
1348     return;
1349
1350   // Now get a list of the function with references to non split-stack
1351   // code.
1352
1353   Function_offsets calls_non_split;
1354   for (std::vector<section_offset_type>::const_iterator p
1355          = non_split_refs.begin();
1356        p != non_split_refs.end();
1357        ++p)
1358     {
1359       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1360       if (low == function_offsets.end())
1361         --low;
1362       else if (low->first == *p)
1363         ;
1364       else if (low == function_offsets.begin())
1365         continue;
1366       else
1367         --low;
1368
1369       calls_non_split.insert(*low);
1370     }
1371   if (calls_non_split.empty())
1372     return;
1373
1374   // Now we have a set of functions to adjust.  The adjustments are
1375   // target specific.  Besides changing the output section view
1376   // however, it likes, the target may request a relocation change
1377   // from one global symbol name to another.
1378
1379   for (Function_offsets::const_iterator p = calls_non_split.begin();
1380        p != calls_non_split.end();
1381        ++p)
1382     {
1383       std::string from;
1384       std::string to;
1385       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1386                                            view, view_size, &from, &to);
1387       if (!from.empty())
1388         {
1389           gold_assert(!to.empty());
1390           Symbol* tosym = NULL;
1391
1392           // Find relocations in the relevant function which are for
1393           // FROM.
1394           pr = prelocs;
1395           for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1396             {
1397               Reltype reloc(pr);
1398
1399               typename elfcpp::Elf_types<size>::Elf_WXword r_info =
1400                 reloc.get_r_info();
1401               unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1402               if (r_sym < local_count)
1403                 continue;
1404
1405               section_offset_type offset =
1406                 convert_to_section_size_type(reloc.get_r_offset());
1407               if (offset < p->first
1408                   || (offset
1409                       >= (p->first
1410                           + static_cast<section_offset_type>(p->second))))
1411                 continue;
1412
1413               const Symbol* gsym = this->global_symbol(r_sym);
1414               if (from == gsym->name())
1415                 {
1416                   if (tosym == NULL)
1417                     {
1418                       tosym = symtab->lookup(to.c_str());
1419                       if (tosym == NULL)
1420                         {
1421                           this->error(_("could not convert call "
1422                                         "to '%s' to '%s'"),
1423                                       from.c_str(), to.c_str());
1424                           break;
1425                         }
1426                     }
1427
1428                   if (*reloc_map == NULL)
1429                     *reloc_map = new Reloc_symbol_changes(reloc_count);
1430                   (*reloc_map)->set(i, tosym);
1431                 }
1432             }
1433         }
1434     }
1435 }
1436
1437 // Find all the function in this object defined in section SHNDX.
1438 // Store their offsets in the section in FUNCTION_OFFSETS.
1439
1440 template<int size, bool big_endian>
1441 void
1442 Sized_relobj_file<size, big_endian>::find_functions(
1443     const unsigned char* pshdrs,
1444     unsigned int shndx,
1445     Sized_relobj_file<size, big_endian>::Function_offsets* function_offsets)
1446 {
1447   // We need to read the symbols to find the functions.  If we wanted
1448   // to, we could cache reading the symbols across all sections in the
1449   // object.
1450   const unsigned int symtab_shndx = this->symtab_shndx_;
1451   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1452   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1453
1454   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1455     symtabshdr.get_sh_size();
1456   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1457                                               sh_size, true, true);
1458
1459   const int sym_size = This::sym_size;
1460   const unsigned int symcount = sh_size / sym_size;
1461   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1462     {
1463       typename elfcpp::Sym<size, big_endian> isym(psyms);
1464
1465       // FIXME: Some targets can have functions which do not have type
1466       // STT_FUNC, e.g., STT_ARM_TFUNC.
1467       if (isym.get_st_type() != elfcpp::STT_FUNC
1468           || isym.get_st_size() == 0)
1469         continue;
1470
1471       bool is_ordinary;
1472       unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1473                                                       &is_ordinary);
1474       if (!is_ordinary || sym_shndx != shndx)
1475         continue;
1476
1477       section_offset_type value =
1478         convert_to_section_size_type(isym.get_st_value());
1479       section_size_type fnsize =
1480         convert_to_section_size_type(isym.get_st_size());
1481
1482       (*function_offsets)[value] = fnsize;
1483     }
1484 }
1485
1486 // Class Merged_symbol_value.
1487
1488 template<int size>
1489 void
1490 Merged_symbol_value<size>::initialize_input_to_output_map(
1491     const Relobj* object,
1492     unsigned int input_shndx)
1493 {
1494   Object_merge_map* map = object->merge_map();
1495   map->initialize_input_to_output_map<size>(input_shndx,
1496                                             this->output_start_address_,
1497                                             &this->output_addresses_);
1498 }
1499
1500 // Get the output value corresponding to an input offset if we
1501 // couldn't find it in the hash table.
1502
1503 template<int size>
1504 typename elfcpp::Elf_types<size>::Elf_Addr
1505 Merged_symbol_value<size>::value_from_output_section(
1506     const Relobj* object,
1507     unsigned int input_shndx,
1508     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1509 {
1510   section_offset_type output_offset;
1511   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
1512                                                       input_offset,
1513                                                       &output_offset);
1514
1515   // If this assertion fails, it means that some relocation was
1516   // against a portion of an input merge section which we didn't map
1517   // to the output file and we didn't explicitly discard.  We should
1518   // always map all portions of input merge sections.
1519   gold_assert(found);
1520
1521   if (output_offset == -1)
1522     return 0;
1523   else
1524     return this->output_start_address_ + output_offset;
1525 }
1526
1527 // Track_relocs methods.
1528
1529 // Initialize the class to track the relocs.  This gets the object,
1530 // the reloc section index, and the type of the relocs.  This returns
1531 // false if something goes wrong.
1532
1533 template<int size, bool big_endian>
1534 bool
1535 Track_relocs<size, big_endian>::initialize(
1536     Object* object,
1537     unsigned int reloc_shndx,
1538     unsigned int reloc_type)
1539 {
1540   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1541   // section for the .eh_frame section.  We can't handle that case.
1542   if (reloc_shndx == -1U)
1543     return false;
1544
1545   // If RELOC_SHNDX is 0, there is no reloc section.
1546   if (reloc_shndx == 0)
1547     return true;
1548
1549   // Get the contents of the reloc section.
1550   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1551
1552   if (reloc_type == elfcpp::SHT_REL)
1553     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1554   else if (reloc_type == elfcpp::SHT_RELA)
1555     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1556   else
1557     gold_unreachable();
1558
1559   if (this->len_ % this->reloc_size_ != 0)
1560     {
1561       object->error(_("reloc section size %zu is not a multiple of "
1562                       "reloc size %d\n"),
1563                     static_cast<size_t>(this->len_),
1564                     this->reloc_size_);
1565       return false;
1566     }
1567
1568   return true;
1569 }
1570
1571 // Return the offset of the next reloc, or -1 if there isn't one.
1572
1573 template<int size, bool big_endian>
1574 off_t
1575 Track_relocs<size, big_endian>::next_offset() const
1576 {
1577   if (this->pos_ >= this->len_)
1578     return -1;
1579
1580   // Rel and Rela start out the same, so we can always use Rel to find
1581   // the r_offset value.
1582   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1583   return rel.get_r_offset();
1584 }
1585
1586 // Return the index of the symbol referenced by the next reloc, or -1U
1587 // if there aren't any more relocs.
1588
1589 template<int size, bool big_endian>
1590 unsigned int
1591 Track_relocs<size, big_endian>::next_symndx() const
1592 {
1593   if (this->pos_ >= this->len_)
1594     return -1U;
1595
1596   // Rel and Rela start out the same, so we can use Rel to find the
1597   // symbol index.
1598   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1599   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1600 }
1601
1602 // Return the addend of the next reloc, or 0 if there isn't one.
1603
1604 template<int size, bool big_endian>
1605 uint64_t
1606 Track_relocs<size, big_endian>::next_addend() const
1607 {
1608   if (this->pos_ >= this->len_)
1609     return 0;
1610   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1611     return 0;
1612   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1613   return rela.get_r_addend();
1614 }
1615
1616 // Advance to the next reloc whose r_offset is greater than or equal
1617 // to OFFSET.  Return the number of relocs we skip.
1618
1619 template<int size, bool big_endian>
1620 int
1621 Track_relocs<size, big_endian>::advance(off_t offset)
1622 {
1623   int ret = 0;
1624   while (this->pos_ < this->len_)
1625     {
1626       // Rel and Rela start out the same, so we can always use Rel to
1627       // find the r_offset value.
1628       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1629       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1630         break;
1631       ++ret;
1632       this->pos_ += this->reloc_size_;
1633     }
1634   return ret;
1635 }
1636
1637 // Instantiate the templates we need.
1638
1639 #ifdef HAVE_TARGET_32_LITTLE
1640 template
1641 void
1642 Sized_relobj_file<32, false>::do_read_relocs(Read_relocs_data* rd);
1643 #endif
1644
1645 #ifdef HAVE_TARGET_32_BIG
1646 template
1647 void
1648 Sized_relobj_file<32, true>::do_read_relocs(Read_relocs_data* rd);
1649 #endif
1650
1651 #ifdef HAVE_TARGET_64_LITTLE
1652 template
1653 void
1654 Sized_relobj_file<64, false>::do_read_relocs(Read_relocs_data* rd);
1655 #endif
1656
1657 #ifdef HAVE_TARGET_64_BIG
1658 template
1659 void
1660 Sized_relobj_file<64, true>::do_read_relocs(Read_relocs_data* rd);
1661 #endif
1662
1663 #ifdef HAVE_TARGET_32_LITTLE
1664 template
1665 void
1666 Sized_relobj_file<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1667                                                    Layout* layout,
1668                                                    Read_relocs_data* rd);
1669 #endif
1670
1671 #ifdef HAVE_TARGET_32_BIG
1672 template
1673 void
1674 Sized_relobj_file<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1675                                                   Layout* layout,
1676                                                   Read_relocs_data* rd);
1677 #endif
1678
1679 #ifdef HAVE_TARGET_64_LITTLE
1680 template
1681 void
1682 Sized_relobj_file<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1683                                                    Layout* layout,
1684                                                    Read_relocs_data* rd);
1685 #endif
1686
1687 #ifdef HAVE_TARGET_64_BIG
1688 template
1689 void
1690 Sized_relobj_file<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1691                                                   Layout* layout,
1692                                                   Read_relocs_data* rd);
1693 #endif
1694
1695 #ifdef HAVE_TARGET_32_LITTLE
1696 template
1697 void
1698 Sized_relobj_file<32, false>::do_scan_relocs(Symbol_table* symtab,
1699                                              Layout* layout,
1700                                              Read_relocs_data* rd);
1701 #endif
1702
1703 #ifdef HAVE_TARGET_32_BIG
1704 template
1705 void
1706 Sized_relobj_file<32, true>::do_scan_relocs(Symbol_table* symtab,
1707                                             Layout* layout,
1708                                             Read_relocs_data* rd);
1709 #endif
1710
1711 #ifdef HAVE_TARGET_64_LITTLE
1712 template
1713 void
1714 Sized_relobj_file<64, false>::do_scan_relocs(Symbol_table* symtab,
1715                                              Layout* layout,
1716                                              Read_relocs_data* rd);
1717 #endif
1718
1719 #ifdef HAVE_TARGET_64_BIG
1720 template
1721 void
1722 Sized_relobj_file<64, true>::do_scan_relocs(Symbol_table* symtab,
1723                                             Layout* layout,
1724                                             Read_relocs_data* rd);
1725 #endif
1726
1727 #ifdef HAVE_TARGET_32_LITTLE
1728 template
1729 void
1730 Sized_relobj_file<32, false>::do_relocate(const Symbol_table* symtab,
1731                                           const Layout* layout,
1732                                           Output_file* of);
1733 #endif
1734
1735 #ifdef HAVE_TARGET_32_BIG
1736 template
1737 void
1738 Sized_relobj_file<32, true>::do_relocate(const Symbol_table* symtab,
1739                                          const Layout* layout,
1740                                          Output_file* of);
1741 #endif
1742
1743 #ifdef HAVE_TARGET_64_LITTLE
1744 template
1745 void
1746 Sized_relobj_file<64, false>::do_relocate(const Symbol_table* symtab,
1747                                           const Layout* layout,
1748                                           Output_file* of);
1749 #endif
1750
1751 #ifdef HAVE_TARGET_64_BIG
1752 template
1753 void
1754 Sized_relobj_file<64, true>::do_relocate(const Symbol_table* symtab,
1755                                          const Layout* layout,
1756                                          Output_file* of);
1757 #endif
1758
1759 #ifdef HAVE_TARGET_32_LITTLE
1760 template
1761 void
1762 Sized_relobj_file<32, false>::do_relocate_sections(
1763     const Symbol_table* symtab,
1764     const Layout* layout,
1765     const unsigned char* pshdrs,
1766     Output_file* of,
1767     Views* pviews);
1768 #endif
1769
1770 #ifdef HAVE_TARGET_32_BIG
1771 template
1772 void
1773 Sized_relobj_file<32, true>::do_relocate_sections(
1774     const Symbol_table* symtab,
1775     const Layout* layout,
1776     const unsigned char* pshdrs,
1777     Output_file* of,
1778     Views* pviews);
1779 #endif
1780
1781 #ifdef HAVE_TARGET_64_LITTLE
1782 template
1783 void
1784 Sized_relobj_file<64, false>::do_relocate_sections(
1785     const Symbol_table* symtab,
1786     const Layout* layout,
1787     const unsigned char* pshdrs,
1788     Output_file* of,
1789     Views* pviews);
1790 #endif
1791
1792 #ifdef HAVE_TARGET_64_BIG
1793 template
1794 void
1795 Sized_relobj_file<64, true>::do_relocate_sections(
1796     const Symbol_table* symtab,
1797     const Layout* layout,
1798     const unsigned char* pshdrs,
1799     Output_file* of,
1800     Views* pviews);
1801 #endif
1802
1803 #ifdef HAVE_TARGET_32_LITTLE
1804 template
1805 void
1806 Sized_relobj_file<32, false>::initialize_input_to_output_maps();
1807
1808 template
1809 void
1810 Sized_relobj_file<32, false>::free_input_to_output_maps();
1811 #endif
1812
1813 #ifdef HAVE_TARGET_32_BIG
1814 template
1815 void
1816 Sized_relobj_file<32, true>::initialize_input_to_output_maps();
1817
1818 template
1819 void
1820 Sized_relobj_file<32, true>::free_input_to_output_maps();
1821 #endif
1822
1823 #ifdef HAVE_TARGET_64_LITTLE
1824 template
1825 void
1826 Sized_relobj_file<64, false>::initialize_input_to_output_maps();
1827
1828 template
1829 void
1830 Sized_relobj_file<64, false>::free_input_to_output_maps();
1831 #endif
1832
1833 #ifdef HAVE_TARGET_64_BIG
1834 template
1835 void
1836 Sized_relobj_file<64, true>::initialize_input_to_output_maps();
1837
1838 template
1839 void
1840 Sized_relobj_file<64, true>::free_input_to_output_maps();
1841 #endif
1842
1843 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1844 template
1845 class Merged_symbol_value<32>;
1846 #endif
1847
1848 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1849 template
1850 class Merged_symbol_value<64>;
1851 #endif
1852
1853 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1854 template
1855 class Symbol_value<32>;
1856 #endif
1857
1858 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1859 template
1860 class Symbol_value<64>;
1861 #endif
1862
1863 #ifdef HAVE_TARGET_32_LITTLE
1864 template
1865 class Track_relocs<32, false>;
1866 #endif
1867
1868 #ifdef HAVE_TARGET_32_BIG
1869 template
1870 class Track_relocs<32, true>;
1871 #endif
1872
1873 #ifdef HAVE_TARGET_64_LITTLE
1874 template
1875 class Track_relocs<64, false>;
1876 #endif
1877
1878 #ifdef HAVE_TARGET_64_BIG
1879 template
1880 class Track_relocs<64, true>;
1881 #endif
1882
1883 } // End namespace gold.