gold/target-reloc.h

   1 // target-reloc.h -- target specific relocation support  -*- C++ -*-
   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 #ifndef GOLD_TARGET_RELOC_H
  24 #define GOLD_TARGET_RELOC_H
  25
  26 #include "elfcpp.h"
  27 #include "symtab.h"
  28 #include "object.h"
  29 #include "reloc.h"
  30 #include "reloc-types.h"
  31
  32 namespace gold
  33 {
  34
  35 // This function implements the generic part of reloc scanning.  The
  36 // template parameter Scan must be a class type which provides two
  37 // functions: local() and global().  Those functions implement the
  38 // machine specific part of scanning.  We do it this way to
  39 // avoid making a function call for each relocation, and to avoid
  40 // repeating the generic code for each target.
  41
  42 template<int size, bool big_endian, typename Target_type, int sh_type,
  43          typename Scan>
  44 inline void
  45 scan_relocs(
  46     Symbol_table* symtab,
  47     Layout* layout,
  48     Target_type* target,
  49     Sized_relobj_file<size, big_endian>* object,
  50     unsigned int data_shndx,
  51     const unsigned char* prelocs,
  52     size_t reloc_count,
  53     Output_section* output_section,
  54     bool needs_special_offset_handling,
  55     size_t local_count,
  56     const unsigned char* plocal_syms)
  57 {
  58   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
  59   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
  60   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
  61   Scan scan;
  62
  63   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
  64     {
  65       Reltype reloc(prelocs);
  66
  67       if (needs_special_offset_handling
  68           && !output_section->is_input_address_mapped(object, data_shndx,
  69                                                       reloc.get_r_offset()))
  70         continue;
  71
  72       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
  73       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
  74       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
  75
  76       if (r_sym < local_count)
  77         {
  78           gold_assert(plocal_syms != NULL);
  79           typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
  80                                                       + r_sym * sym_size);
  81           unsigned int shndx = lsym.get_st_shndx();
  82           bool is_ordinary;
  83           shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
  84           if (is_ordinary
  85               && shndx != elfcpp::SHN_UNDEF
  86               && !object->is_section_included(shndx)
  87               && !symtab->is_section_folded(object, shndx))
  88             {
  89               // RELOC is a relocation against a local symbol in a
  90               // section we are discarding.  We can ignore this
  91               // relocation.  It will eventually become a reloc
  92               // against the value zero.
  93               //
  94               // FIXME: We should issue a warning if this is an
  95               // allocated section; is this the best place to do it?
  96               //
  97               // FIXME: The old GNU linker would in some cases look
  98               // for the linkonce section which caused this section to
  99               // be discarded, and, if the other section was the same
 100               // size, change the reloc to refer to the other section.
 101               // That seems risky and weird to me, and I don't know of
 102               // any case where it is actually required.
 103
 104               continue;
 105             }
 106           scan.local(symtab, layout, target, object, data_shndx,
 107                      output_section, reloc, r_type, lsym);
 108         }
 109       else
 110         {
 111           Symbol* gsym = object->global_symbol(r_sym);
 112           gold_assert(gsym != NULL);
 113           if (gsym->is_forwarder())
 114             gsym = symtab->resolve_forwards(gsym);
 115
 116           scan.global(symtab, layout, target, object, data_shndx,
 117                       output_section, reloc, r_type, gsym);
 118         }
 119     }
 120 }
 121
 122 // Behavior for relocations to discarded comdat sections.
 123
 124 enum Comdat_behavior
 125 {
 126   CB_UNDETERMINED,   // Not yet determined -- need to look at section name.
 127   CB_PRETEND,        // Attempt to map to the corresponding kept section.
 128   CB_IGNORE,         // Ignore the relocation.
 129   CB_WARNING         // Print a warning.
 130 };
 131
 132 // Decide what the linker should do for relocations that refer to discarded
 133 // comdat sections.  This decision is based on the name of the section being
 134 // relocated.
 135
 136 inline Comdat_behavior
 137 get_comdat_behavior(const char* name)
 138 {
 139   if (Layout::is_debug_info_section(name))
 140     return CB_PRETEND;
 141   if (strcmp(name, ".eh_frame") == 0
 142       || strcmp(name, ".gcc_except_table") == 0)
 143     return CB_IGNORE;
 144   return CB_WARNING;
 145 }
 146
 147 // Give an error for a symbol with non-default visibility which is not
 148 // defined locally.
 149
 150 inline void
 151 visibility_error(const Symbol* sym)
 152 {
 153   const char* v;
 154   switch (sym->visibility())
 155     {
 156     case elfcpp::STV_INTERNAL:
 157       v = _("internal");
 158       break;
 159     case elfcpp::STV_HIDDEN:
 160       v = _("hidden");
 161       break;
 162     case elfcpp::STV_PROTECTED:
 163       v = _("protected");
 164       break;
 165     default:
 166       gold_unreachable();
 167     }
 168   gold_error(_("%s symbol '%s' is not defined locally"),
 169              v, sym->name());
 170 }
 171
 172 // Return true if we are should issue an error saying that SYM is an
 173 // undefined symbol.  This is called if there is a relocation against
 174 // SYM.
 175
 176 inline bool
 177 issue_undefined_symbol_error(const Symbol* sym)
 178 {
 179   // We only report global symbols.
 180   if (sym == NULL)
 181     return false;
 182
 183   // We only report undefined symbols.
 184   if (!sym->is_undefined() && !sym->is_placeholder())
 185     return false;
 186
 187   // We don't report weak symbols.
 188   if (sym->binding() == elfcpp::STB_WEAK)
 189     return false;
 190
 191   // We don't report symbols defined in discarded sections.
 192   if (sym->is_defined_in_discarded_section())
 193     return false;
 194
 195   // If the target defines this symbol, don't report it here.
 196   if (parameters->target().is_defined_by_abi(sym))
 197     return false;
 198
 199   // See if we've been told to ignore whether this symbol is
 200   // undefined.
 201   const char* const u = parameters->options().unresolved_symbols();
 202   if (u != NULL)
 203     {
 204       if (strcmp(u, "ignore-all") == 0)
 205         return false;
 206       if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn())
 207         return false;
 208       if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg())
 209         return false;
 210     }
 211
 212   // When creating a shared library, only report unresolved symbols if
 213   // -z defs was used.
 214   if (parameters->options().shared() && !parameters->options().defs())
 215     return false;
 216
 217   // Otherwise issue a warning.
 218   return true;
 219 }
 220
 221 // This function implements the generic part of relocation processing.
 222 // The template parameter Relocate must be a class type which provides
 223 // a single function, relocate(), which implements the machine
 224 // specific part of a relocation.
 225
 226 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 227 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 228 // RELOCATE implements operator() to do a relocation.
 229
 230 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 231 // of relocs.  OUTPUT_SECTION is the output section.
 232 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
 233 // mapped to output offsets.
 234
 235 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
 236 // VIEW_SIZE is the size.  These refer to the input section, unless
 237 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
 238 // the output section.
 239
 240 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
 241 // not NULL, it is a vector indexed by relocation index.  If that
 242 // entry is not NULL, it points to a global symbol which used as the
 243 // symbol for the relocation, ignoring the symbol index in the
 244 // relocation.
 245
 246 template<int size, bool big_endian, typename Target_type, int sh_type,
 247          typename Relocate>
 248 inline void
 249 relocate_section(
 250     const Relocate_info<size, big_endian>* relinfo,
 251     Target_type* target,
 252     const unsigned char* prelocs,
 253     size_t reloc_count,
 254     Output_section* output_section,
 255     bool needs_special_offset_handling,
 256     unsigned char* view,
 257     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 258     section_size_type view_size,
 259     const Reloc_symbol_changes* reloc_symbol_changes)
 260 {
 261   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 262   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 263   Relocate relocate;
 264
 265   Sized_relobj_file<size, big_endian>* object = relinfo->object;
 266   unsigned int local_count = object->local_symbol_count();
 267
 268   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
 269
 270   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 271     {
 272       Reltype reloc(prelocs);
 273
 274       section_offset_type offset =
 275         convert_to_section_size_type(reloc.get_r_offset());
 276
 277       if (needs_special_offset_handling)
 278         {
 279           offset = output_section->output_offset(relinfo->object,
 280                                                  relinfo->data_shndx,
 281                                                  offset);
 282           if (offset == -1)
 283             continue;
 284         }
 285
 286       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 287       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 288       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 289
 290       const Sized_symbol<size>* sym;
 291
 292       Symbol_value<size> symval;
 293       const Symbol_value<size> *psymval;
 294       bool is_defined_in_discarded_section;
 295       unsigned int shndx;
 296       if (r_sym < local_count
 297           && (reloc_symbol_changes == NULL
 298               || (*reloc_symbol_changes)[i] == NULL))
 299         {
 300           sym = NULL;
 301           psymval = object->local_symbol(r_sym);
 302
 303           // If the local symbol belongs to a section we are discarding,
 304           // and that section is a debug section, try to find the
 305           // corresponding kept section and map this symbol to its
 306           // counterpart in the kept section.  The symbol must not
 307           // correspond to a section we are folding.
 308           bool is_ordinary;
 309           shndx = psymval->input_shndx(&is_ordinary);
 310           is_defined_in_discarded_section =
 311             (is_ordinary
 312              && shndx != elfcpp::SHN_UNDEF
 313              && !object->is_section_included(shndx)
 314              && !relinfo->symtab->is_section_folded(object, shndx));
 315         }
 316       else
 317         {
 318           const Symbol* gsym;
 319           if (reloc_symbol_changes != NULL
 320               && (*reloc_symbol_changes)[i] != NULL)
 321             gsym = (*reloc_symbol_changes)[i];
 322           else
 323             {
 324               gsym = object->global_symbol(r_sym);
 325               gold_assert(gsym != NULL);
 326               if (gsym->is_forwarder())
 327                 gsym = relinfo->symtab->resolve_forwards(gsym);
 328             }
 329
 330           sym = static_cast<const Sized_symbol<size>*>(gsym);
 331           if (sym->has_symtab_index() && sym->symtab_index() != -1U)
 332             symval.set_output_symtab_index(sym->symtab_index());
 333           else
 334             symval.set_no_output_symtab_entry();
 335           symval.set_output_value(sym->value());
 336           if (gsym->type() == elfcpp::STT_TLS)
 337             symval.set_is_tls_symbol();
 338           else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 339             symval.set_is_ifunc_symbol();
 340           psymval = &symval;
 341
 342           is_defined_in_discarded_section =
 343             (gsym->is_defined_in_discarded_section()
 344              && gsym->is_undefined());
 345           shndx = 0;
 346         }
 347
 348       Symbol_value<size> symval2;
 349       if (is_defined_in_discarded_section)
 350         {
 351           if (comdat_behavior == CB_UNDETERMINED)
 352             {
 353               std::string name = object->section_name(relinfo->data_shndx);
 354               comdat_behavior = get_comdat_behavior(name.c_str());
 355             }
 356           if (comdat_behavior == CB_PRETEND)
 357             {
 358               // FIXME: This case does not work for global symbols.
 359               // We have no place to store the original section index.
 360               // Fortunately this does not matter for comdat sections,
 361               // only for sections explicitly discarded by a linker
 362               // script.
 363               bool found;
 364               typename elfcpp::Elf_types<size>::Elf_Addr value =
 365                 object->map_to_kept_section(shndx, &found);
 366               if (found)
 367                 symval2.set_output_value(value + psymval->input_value());
 368               else
 369                 symval2.set_output_value(0);
 370             }
 371           else
 372             {
 373               if (comdat_behavior == CB_WARNING)
 374                 gold_warning_at_location(relinfo, i, offset,
 375                                          _("relocation refers to discarded "
 376                                            "section"));
 377               symval2.set_output_value(0);
 378             }
 379           symval2.set_no_output_symtab_entry();
 380           psymval = &symval2;
 381         }
 382
 383       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
 384                              r_type, sym, psymval, view + offset,
 385                              view_address + offset, view_size))
 386         continue;
 387
 388       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
 389         {
 390           gold_error_at_location(relinfo, i, offset,
 391                                  _("reloc has bad offset %zu"),
 392                                  static_cast<size_t>(offset));
 393           continue;
 394         }
 395
 396       if (issue_undefined_symbol_error(sym))
 397         gold_undefined_symbol_at_location(sym, relinfo, i, offset);
 398       else if (sym != NULL
 399                && sym->visibility() != elfcpp::STV_DEFAULT
 400                && (sym->is_undefined() || sym->is_from_dynobj()))
 401         visibility_error(sym);
 402
 403       if (sym != NULL && sym->has_warning())
 404         relinfo->symtab->issue_warning(sym, relinfo, i, offset);
 405     }
 406 }
 407
 408 // Apply an incremental relocation.
 409
 410 template<int size, bool big_endian, typename Target_type,
 411          typename Relocate>
 412 void
 413 apply_relocation(const Relocate_info<size, big_endian>* relinfo,
 414                  Target_type* target,
 415                  typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
 416                  unsigned int r_type,
 417                  typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
 418                  const Symbol* gsym,
 419                  unsigned char* view,
 420                  typename elfcpp::Elf_types<size>::Elf_Addr address,
 421                  section_size_type view_size)
 422 {
 423   // Construct the ELF relocation in a temporary buffer.
 424   const int reloc_size = elfcpp::Elf_sizes<64>::rela_size;
 425   unsigned char relbuf[reloc_size];
 426   elfcpp::Rela<64, false> rel(relbuf);
 427   elfcpp::Rela_write<64, false> orel(relbuf);
 428   orel.put_r_offset(r_offset);
 429   orel.put_r_info(elfcpp::elf_r_info<64>(0, r_type));
 430   orel.put_r_addend(r_addend);
 431
 432   // Setup a Symbol_value for the global symbol.
 433   const Sized_symbol<64>* sym = static_cast<const Sized_symbol<64>*>(gsym);
 434   Symbol_value<64> symval;
 435   gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U);
 436   symval.set_output_symtab_index(sym->symtab_index());
 437   symval.set_output_value(sym->value());
 438   if (gsym->type() == elfcpp::STT_TLS)
 439     symval.set_is_tls_symbol();
 440   else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 441     symval.set_is_ifunc_symbol();
 442
 443   Relocate relocate;
 444   relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval,
 445                     view + r_offset, address + r_offset, view_size);
 446 }
 447
 448 // This class may be used as a typical class for the
 449 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
 450 // template parameter Classify_reloc must be a class type which
 451 // provides a function get_size_for_reloc which returns the number of
 452 // bytes to which a reloc applies.  This class is intended to capture
 453 // the most typical target behaviour, while still permitting targets
 454 // to define their own independent class for Scan_relocatable_reloc.
 455
 456 template<int sh_type, typename Classify_reloc>
 457 class Default_scan_relocatable_relocs
 458 {
 459  public:
 460   // Return the strategy to use for a local symbol which is not a
 461   // section symbol, given the relocation type.
 462   inline Relocatable_relocs::Reloc_strategy
 463   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
 464   {
 465     // We assume that relocation type 0 is NONE.  Targets which are
 466     // different must override.
 467     if (r_type == 0 && r_sym == 0)
 468       return Relocatable_relocs::RELOC_DISCARD;
 469     return Relocatable_relocs::RELOC_COPY;
 470   }
 471
 472   // Return the strategy to use for a local symbol which is a section
 473   // symbol, given the relocation type.
 474   inline Relocatable_relocs::Reloc_strategy
 475   local_section_strategy(unsigned int r_type, Relobj* object)
 476   {
 477     if (sh_type == elfcpp::SHT_RELA)
 478       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 479     else
 480       {
 481         Classify_reloc classify;
 482         switch (classify.get_size_for_reloc(r_type, object))
 483           {
 484           case 0:
 485             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 486           case 1:
 487             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
 488           case 2:
 489             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
 490           case 4:
 491             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
 492           case 8:
 493             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
 494           default:
 495             gold_unreachable();
 496           }
 497       }
 498   }
 499
 500   // Return the strategy to use for a global symbol, given the
 501   // relocation type, the object, and the symbol index.
 502   inline Relocatable_relocs::Reloc_strategy
 503   global_strategy(unsigned int, Relobj*, unsigned int)
 504   { return Relocatable_relocs::RELOC_COPY; }
 505 };
 506
 507 // Scan relocs during a relocatable link.  This is a default
 508 // definition which should work for most targets.
 509 // Scan_relocatable_reloc must name a class type which provides three
 510 // functions which return a Relocatable_relocs::Reloc_strategy code:
 511 // global_strategy, local_non_section_strategy, and
 512 // local_section_strategy.  Most targets should be able to use
 513 // Default_scan_relocatable_relocs as this class.
 514
 515 template<int size, bool big_endian, int sh_type,
 516          typename Scan_relocatable_reloc>
 517 void
 518 scan_relocatable_relocs(
 519     Symbol_table*,
 520     Layout*,
 521     Sized_relobj_file<size, big_endian>* object,
 522     unsigned int data_shndx,
 523     const unsigned char* prelocs,
 524     size_t reloc_count,
 525     Output_section* output_section,
 526     bool needs_special_offset_handling,
 527     size_t local_symbol_count,
 528     const unsigned char* plocal_syms,
 529     Relocatable_relocs* rr)
 530 {
 531   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 532   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 533   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 534   Scan_relocatable_reloc scan;
 535
 536   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 537     {
 538       Reltype reloc(prelocs);
 539
 540       Relocatable_relocs::Reloc_strategy strategy;
 541
 542       if (needs_special_offset_handling
 543           && !output_section->is_input_address_mapped(object, data_shndx,
 544                                                       reloc.get_r_offset()))
 545         strategy = Relocatable_relocs::RELOC_DISCARD;
 546       else
 547         {
 548           typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 549             reloc.get_r_info();
 550           const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 551           const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 552
 553           if (r_sym >= local_symbol_count)
 554             strategy = scan.global_strategy(r_type, object, r_sym);
 555           else
 556             {
 557               gold_assert(plocal_syms != NULL);
 558               typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
 559                                                           + r_sym * sym_size);
 560               unsigned int shndx = lsym.get_st_shndx();
 561               bool is_ordinary;
 562               shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
 563               if (is_ordinary
 564                   && shndx != elfcpp::SHN_UNDEF
 565                   && !object->is_section_included(shndx))
 566                 {
 567                   // RELOC is a relocation against a local symbol
 568                   // defined in a section we are discarding.  Discard
 569                   // the reloc.  FIXME: Should we issue a warning?
 570                   strategy = Relocatable_relocs::RELOC_DISCARD;
 571                 }
 572               else if (lsym.get_st_type() != elfcpp::STT_SECTION)
 573                 strategy = scan.local_non_section_strategy(r_type, object,
 574                                                            r_sym);
 575               else
 576                 {
 577                   strategy = scan.local_section_strategy(r_type, object);
 578                   if (strategy != Relocatable_relocs::RELOC_DISCARD)
 579                     object->output_section(shndx)->set_needs_symtab_index();
 580                 }
 581
 582               if (strategy == Relocatable_relocs::RELOC_COPY)
 583                 object->set_must_have_output_symtab_entry(r_sym);
 584             }
 585         }
 586
 587       rr->set_next_reloc_strategy(strategy);
 588     }
 589 }
 590
 591 // Relocate relocs during a relocatable link.  This is a default
 592 // definition which should work for most targets.
 593
 594 template<int size, bool big_endian, int sh_type>
 595 void
 596 relocate_for_relocatable(
 597     const Relocate_info<size, big_endian>* relinfo,
 598     const unsigned char* prelocs,
 599     size_t reloc_count,
 600     Output_section* output_section,
 601     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 602     const Relocatable_relocs* rr,
 603     unsigned char* view,
 604     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 605     section_size_type view_size,
 606     unsigned char* reloc_view,
 607     section_size_type reloc_view_size)
 608 {
 609   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 610   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 611   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
 612     Reltype_write;
 613   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 614   const Address invalid_address = static_cast<Address>(0) - 1;
 615
 616   Sized_relobj_file<size, big_endian>* const object = relinfo->object;
 617   const unsigned int local_count = object->local_symbol_count();
 618
 619   unsigned char* pwrite = reloc_view;
 620
 621   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 622     {
 623       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
 624       if (strategy == Relocatable_relocs::RELOC_DISCARD)
 625         continue;
 626
 627       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
 628         {
 629           // Target wants to handle this relocation.
 630           Sized_target<size, big_endian>* target =
 631             parameters->sized_target<size, big_endian>();
 632           target->relocate_special_relocatable(relinfo, sh_type, prelocs,
 633                                                i, output_section,
 634                                                offset_in_output_section,
 635                                                view, view_address,
 636                                                view_size, pwrite);
 637           pwrite += reloc_size;
 638           continue;
 639         }
 640       Reltype reloc(prelocs);
 641       Reltype_write reloc_write(pwrite);
 642
 643       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 644       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 645       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 646
 647       // Get the new symbol index.
 648
 649       unsigned int new_symndx;
 650       if (r_sym < local_count)
 651         {
 652           switch (strategy)
 653             {
 654             case Relocatable_relocs::RELOC_COPY:
 655               if (r_sym == 0)
 656                 new_symndx = 0;
 657               else
 658                 {
 659                   new_symndx = object->symtab_index(r_sym);
 660                   gold_assert(new_symndx != -1U);
 661                 }
 662               break;
 663
 664             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 665             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 666             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 667             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 668             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 669             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 670               {
 671                 // We are adjusting a section symbol.  We need to find
 672                 // the symbol table index of the section symbol for
 673                 // the output section corresponding to input section
 674                 // in which this symbol is defined.
 675                 gold_assert(r_sym < local_count);
 676                 bool is_ordinary;
 677                 unsigned int shndx =
 678                   object->local_symbol_input_shndx(r_sym, &is_ordinary);
 679                 gold_assert(is_ordinary);
 680                 Output_section* os = object->output_section(shndx);
 681                 gold_assert(os != NULL);
 682                 gold_assert(os->needs_symtab_index());
 683                 new_symndx = os->symtab_index();
 684               }
 685               break;
 686
 687             default:
 688               gold_unreachable();
 689             }
 690         }
 691       else
 692         {
 693           const Symbol* gsym = object->global_symbol(r_sym);
 694           gold_assert(gsym != NULL);
 695           if (gsym->is_forwarder())
 696             gsym = relinfo->symtab->resolve_forwards(gsym);
 697
 698           gold_assert(gsym->has_symtab_index());
 699           new_symndx = gsym->symtab_index();
 700         }
 701
 702       // Get the new offset--the location in the output section where
 703       // this relocation should be applied.
 704
 705       Address offset = reloc.get_r_offset();
 706       Address new_offset;
 707       if (offset_in_output_section != invalid_address)
 708         new_offset = offset + offset_in_output_section;
 709       else
 710         {
 711           section_offset_type sot_offset =
 712               convert_types<section_offset_type, Address>(offset);
 713           section_offset_type new_sot_offset =
 714               output_section->output_offset(object, relinfo->data_shndx,
 715                                             sot_offset);
 716           gold_assert(new_sot_offset != -1);
 717           new_offset = new_sot_offset;
 718         }
 719
 720       // In an object file, r_offset is an offset within the section.
 721       // In an executable or dynamic object, generated by
 722       // --emit-relocs, r_offset is an absolute address.
 723       if (!parameters->options().relocatable())
 724         {
 725           new_offset += view_address;
 726           if (offset_in_output_section != invalid_address)
 727             new_offset -= offset_in_output_section;
 728         }
 729
 730       reloc_write.put_r_offset(new_offset);
 731       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
 732
 733       // Handle the reloc addend based on the strategy.
 734
 735       if (strategy == Relocatable_relocs::RELOC_COPY)
 736         {
 737           if (sh_type == elfcpp::SHT_RELA)
 738             Reloc_types<sh_type, size, big_endian>::
 739               copy_reloc_addend(&reloc_write,
 740                                 &reloc);
 741         }
 742       else
 743         {
 744           // The relocation uses a section symbol in the input file.
 745           // We are adjusting it to use a section symbol in the output
 746           // file.  The input section symbol refers to some address in
 747           // the input section.  We need the relocation in the output
 748           // file to refer to that same address.  This adjustment to
 749           // the addend is the same calculation we use for a simple
 750           // absolute relocation for the input section symbol.
 751
 752           const Symbol_value<size>* psymval = object->local_symbol(r_sym);
 753
 754           unsigned char* padd = view + offset;
 755           switch (strategy)
 756             {
 757             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 758               {
 759                 typename elfcpp::Elf_types<size>::Elf_Swxword addend;
 760                 addend = Reloc_types<sh_type, size, big_endian>::
 761                            get_reloc_addend(&reloc);
 762                 addend = psymval->value(object, addend);
 763                 Reloc_types<sh_type, size, big_endian>::
 764                   set_reloc_addend(&reloc_write, addend);
 765               }
 766               break;
 767
 768             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 769               break;
 770
 771             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 772               Relocate_functions<size, big_endian>::rel8(padd, object,
 773                                                          psymval);
 774               break;
 775
 776             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 777               Relocate_functions<size, big_endian>::rel16(padd, object,
 778                                                           psymval);
 779               break;
 780
 781             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 782               Relocate_functions<size, big_endian>::rel32(padd, object,
 783                                                           psymval);
 784               break;
 785
 786             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 787               Relocate_functions<size, big_endian>::rel64(padd, object,
 788                                                           psymval);
 789               break;
 790
 791             default:
 792               gold_unreachable();
 793             }
 794         }
 795
 796       pwrite += reloc_size;
 797     }
 798
 799   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
 800               == reloc_view_size);
 801 }
 802
 803 } // End namespace gold.
 804
 805 #endif // !defined(GOLD_TARGET_RELOC_H)