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, "report-all") == 0)
 207         return true;
 208       if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn())
 209         return false;
 210       if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg())
 211         return false;
 212     }
 213
 214   // When creating a shared library, only report unresolved symbols if
 215   // -z defs was used.
 216   if (parameters->options().shared() && !parameters->options().defs())
 217     return false;
 218
 219   // Otherwise issue a warning.
 220   return true;
 221 }
 222
 223 // This function implements the generic part of relocation processing.
 224 // The template parameter Relocate must be a class type which provides
 225 // a single function, relocate(), which implements the machine
 226 // specific part of a relocation.
 227
 228 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 229 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 230 // RELOCATE implements operator() to do a relocation.
 231
 232 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 233 // of relocs.  OUTPUT_SECTION is the output section.
 234 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
 235 // mapped to output offsets.
 236
 237 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
 238 // VIEW_SIZE is the size.  These refer to the input section, unless
 239 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
 240 // the output section.
 241
 242 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
 243 // not NULL, it is a vector indexed by relocation index.  If that
 244 // entry is not NULL, it points to a global symbol which used as the
 245 // symbol for the relocation, ignoring the symbol index in the
 246 // relocation.
 247
 248 template<int size, bool big_endian, typename Target_type, int sh_type,
 249          typename Relocate>
 250 inline void
 251 relocate_section(
 252     const Relocate_info<size, big_endian>* relinfo,
 253     Target_type* target,
 254     const unsigned char* prelocs,
 255     size_t reloc_count,
 256     Output_section* output_section,
 257     bool needs_special_offset_handling,
 258     unsigned char* view,
 259     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 260     section_size_type view_size,
 261     const Reloc_symbol_changes* reloc_symbol_changes)
 262 {
 263   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 264   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 265   Relocate relocate;
 266
 267   Sized_relobj_file<size, big_endian>* object = relinfo->object;
 268   unsigned int local_count = object->local_symbol_count();
 269
 270   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
 271
 272   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 273     {
 274       Reltype reloc(prelocs);
 275
 276       section_offset_type offset =
 277         convert_to_section_size_type(reloc.get_r_offset());
 278
 279       if (needs_special_offset_handling)
 280         {
 281           offset = output_section->output_offset(relinfo->object,
 282                                                  relinfo->data_shndx,
 283                                                  offset);
 284           if (offset == -1)
 285             continue;
 286         }
 287
 288       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 289       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 290       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 291
 292       const Sized_symbol<size>* sym;
 293
 294       Symbol_value<size> symval;
 295       const Symbol_value<size> *psymval;
 296       bool is_defined_in_discarded_section;
 297       unsigned int shndx;
 298       if (r_sym < local_count
 299           && (reloc_symbol_changes == NULL
 300               || (*reloc_symbol_changes)[i] == NULL))
 301         {
 302           sym = NULL;
 303           psymval = object->local_symbol(r_sym);
 304
 305           // If the local symbol belongs to a section we are discarding,
 306           // and that section is a debug section, try to find the
 307           // corresponding kept section and map this symbol to its
 308           // counterpart in the kept section.  The symbol must not
 309           // correspond to a section we are folding.
 310           bool is_ordinary;
 311           shndx = psymval->input_shndx(&is_ordinary);
 312           is_defined_in_discarded_section =
 313             (is_ordinary
 314              && shndx != elfcpp::SHN_UNDEF
 315              && !object->is_section_included(shndx)
 316              && !relinfo->symtab->is_section_folded(object, shndx));
 317         }
 318       else
 319         {
 320           const Symbol* gsym;
 321           if (reloc_symbol_changes != NULL
 322               && (*reloc_symbol_changes)[i] != NULL)
 323             gsym = (*reloc_symbol_changes)[i];
 324           else
 325             {
 326               gsym = object->global_symbol(r_sym);
 327               gold_assert(gsym != NULL);
 328               if (gsym->is_forwarder())
 329                 gsym = relinfo->symtab->resolve_forwards(gsym);
 330             }
 331
 332           sym = static_cast<const Sized_symbol<size>*>(gsym);
 333           if (sym->has_symtab_index() && sym->symtab_index() != -1U)
 334             symval.set_output_symtab_index(sym->symtab_index());
 335           else
 336             symval.set_no_output_symtab_entry();
 337           symval.set_output_value(sym->value());
 338           if (gsym->type() == elfcpp::STT_TLS)
 339             symval.set_is_tls_symbol();
 340           else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 341             symval.set_is_ifunc_symbol();
 342           psymval = &symval;
 343
 344           is_defined_in_discarded_section =
 345             (gsym->is_defined_in_discarded_section()
 346              && gsym->is_undefined());
 347           shndx = 0;
 348         }
 349
 350       Symbol_value<size> symval2;
 351       if (is_defined_in_discarded_section)
 352         {
 353           if (comdat_behavior == CB_UNDETERMINED)
 354             {
 355               std::string name = object->section_name(relinfo->data_shndx);
 356               comdat_behavior = get_comdat_behavior(name.c_str());
 357             }
 358           if (comdat_behavior == CB_PRETEND)
 359             {
 360               // FIXME: This case does not work for global symbols.
 361               // We have no place to store the original section index.
 362               // Fortunately this does not matter for comdat sections,
 363               // only for sections explicitly discarded by a linker
 364               // script.
 365               bool found;
 366               typename elfcpp::Elf_types<size>::Elf_Addr value =
 367                 object->map_to_kept_section(shndx, &found);
 368               if (found)
 369                 symval2.set_output_value(value + psymval->input_value());
 370               else
 371                 symval2.set_output_value(0);
 372             }
 373           else
 374             {
 375               if (comdat_behavior == CB_WARNING)
 376                 gold_warning_at_location(relinfo, i, offset,
 377                                          _("relocation refers to discarded "
 378                                            "section"));
 379               symval2.set_output_value(0);
 380             }
 381           symval2.set_no_output_symtab_entry();
 382           psymval = &symval2;
 383         }
 384
 385       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
 386                              r_type, sym, psymval, view + offset,
 387                              view_address + offset, view_size))
 388         continue;
 389
 390       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
 391         {
 392           gold_error_at_location(relinfo, i, offset,
 393                                  _("reloc has bad offset %zu"),
 394                                  static_cast<size_t>(offset));
 395           continue;
 396         }
 397
 398       if (issue_undefined_symbol_error(sym))
 399         gold_undefined_symbol_at_location(sym, relinfo, i, offset);
 400       else if (sym != NULL
 401                && sym->visibility() != elfcpp::STV_DEFAULT
 402                && (sym->is_undefined() || sym->is_from_dynobj()))
 403         visibility_error(sym);
 404
 405       if (sym != NULL && sym->has_warning())
 406         relinfo->symtab->issue_warning(sym, relinfo, i, offset);
 407     }
 408 }
 409
 410 // Apply an incremental relocation.
 411
 412 template<int size, bool big_endian, typename Target_type,
 413          typename Relocate>
 414 void
 415 apply_relocation(const Relocate_info<size, big_endian>* relinfo,
 416                  Target_type* target,
 417                  typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
 418                  unsigned int r_type,
 419                  typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
 420                  const Symbol* gsym,
 421                  unsigned char* view,
 422                  typename elfcpp::Elf_types<size>::Elf_Addr address,
 423                  section_size_type view_size)
 424 {
 425   // Construct the ELF relocation in a temporary buffer.
 426   const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 427   unsigned char relbuf[reloc_size];
 428   elfcpp::Rela<size, big_endian> rel(relbuf);
 429   elfcpp::Rela_write<size, big_endian> orel(relbuf);
 430   orel.put_r_offset(r_offset);
 431   orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type));
 432   orel.put_r_addend(r_addend);
 433
 434   // Setup a Symbol_value for the global symbol.
 435   const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym);
 436   Symbol_value<size> symval;
 437   gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U);
 438   symval.set_output_symtab_index(sym->symtab_index());
 439   symval.set_output_value(sym->value());
 440   if (gsym->type() == elfcpp::STT_TLS)
 441     symval.set_is_tls_symbol();
 442   else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 443     symval.set_is_ifunc_symbol();
 444
 445   Relocate relocate;
 446   relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval,
 447                     view + r_offset, address + r_offset, view_size);
 448 }
 449
 450 // This class may be used as a typical class for the
 451 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
 452 // template parameter Classify_reloc must be a class type which
 453 // provides a function get_size_for_reloc which returns the number of
 454 // bytes to which a reloc applies.  This class is intended to capture
 455 // the most typical target behaviour, while still permitting targets
 456 // to define their own independent class for Scan_relocatable_reloc.
 457
 458 template<int sh_type, typename Classify_reloc>
 459 class Default_scan_relocatable_relocs
 460 {
 461  public:
 462   // Return the strategy to use for a local symbol which is not a
 463   // section symbol, given the relocation type.
 464   inline Relocatable_relocs::Reloc_strategy
 465   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
 466   {
 467     // We assume that relocation type 0 is NONE.  Targets which are
 468     // different must override.
 469     if (r_type == 0 && r_sym == 0)
 470       return Relocatable_relocs::RELOC_DISCARD;
 471     return Relocatable_relocs::RELOC_COPY;
 472   }
 473
 474   // Return the strategy to use for a local symbol which is a section
 475   // symbol, given the relocation type.
 476   inline Relocatable_relocs::Reloc_strategy
 477   local_section_strategy(unsigned int r_type, Relobj* object)
 478   {
 479     if (sh_type == elfcpp::SHT_RELA)
 480       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 481     else
 482       {
 483         Classify_reloc classify;
 484         switch (classify.get_size_for_reloc(r_type, object))
 485           {
 486           case 0:
 487             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 488           case 1:
 489             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
 490           case 2:
 491             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
 492           case 4:
 493             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
 494           case 8:
 495             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
 496           default:
 497             gold_unreachable();
 498           }
 499       }
 500   }
 501
 502   // Return the strategy to use for a global symbol, given the
 503   // relocation type, the object, and the symbol index.
 504   inline Relocatable_relocs::Reloc_strategy
 505   global_strategy(unsigned int, Relobj*, unsigned int)
 506   { return Relocatable_relocs::RELOC_COPY; }
 507 };
 508
 509 // Scan relocs during a relocatable link.  This is a default
 510 // definition which should work for most targets.
 511 // Scan_relocatable_reloc must name a class type which provides three
 512 // functions which return a Relocatable_relocs::Reloc_strategy code:
 513 // global_strategy, local_non_section_strategy, and
 514 // local_section_strategy.  Most targets should be able to use
 515 // Default_scan_relocatable_relocs as this class.
 516
 517 template<int size, bool big_endian, int sh_type,
 518          typename Scan_relocatable_reloc>
 519 void
 520 scan_relocatable_relocs(
 521     Symbol_table*,
 522     Layout*,
 523     Sized_relobj_file<size, big_endian>* object,
 524     unsigned int data_shndx,
 525     const unsigned char* prelocs,
 526     size_t reloc_count,
 527     Output_section* output_section,
 528     bool needs_special_offset_handling,
 529     size_t local_symbol_count,
 530     const unsigned char* plocal_syms,
 531     Relocatable_relocs* rr)
 532 {
 533   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 534   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 535   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 536   Scan_relocatable_reloc scan;
 537
 538   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 539     {
 540       Reltype reloc(prelocs);
 541
 542       Relocatable_relocs::Reloc_strategy strategy;
 543
 544       if (needs_special_offset_handling
 545           && !output_section->is_input_address_mapped(object, data_shndx,
 546                                                       reloc.get_r_offset()))
 547         strategy = Relocatable_relocs::RELOC_DISCARD;
 548       else
 549         {
 550           typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 551             reloc.get_r_info();
 552           const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 553           const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 554
 555           if (r_sym >= local_symbol_count)
 556             strategy = scan.global_strategy(r_type, object, r_sym);
 557           else
 558             {
 559               gold_assert(plocal_syms != NULL);
 560               typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
 561                                                           + r_sym * sym_size);
 562               unsigned int shndx = lsym.get_st_shndx();
 563               bool is_ordinary;
 564               shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
 565               if (is_ordinary
 566                   && shndx != elfcpp::SHN_UNDEF
 567                   && !object->is_section_included(shndx))
 568                 {
 569                   // RELOC is a relocation against a local symbol
 570                   // defined in a section we are discarding.  Discard
 571                   // the reloc.  FIXME: Should we issue a warning?
 572                   strategy = Relocatable_relocs::RELOC_DISCARD;
 573                 }
 574               else if (lsym.get_st_type() != elfcpp::STT_SECTION)
 575                 strategy = scan.local_non_section_strategy(r_type, object,
 576                                                            r_sym);
 577               else
 578                 {
 579                   strategy = scan.local_section_strategy(r_type, object);
 580                   if (strategy != Relocatable_relocs::RELOC_DISCARD)
 581                     object->output_section(shndx)->set_needs_symtab_index();
 582                 }
 583
 584               if (strategy == Relocatable_relocs::RELOC_COPY)
 585                 object->set_must_have_output_symtab_entry(r_sym);
 586             }
 587         }
 588
 589       rr->set_next_reloc_strategy(strategy);
 590     }
 591 }
 592
 593 // Relocate relocs.  Called for a relocatable link, and for --emit-relocs.
 594 // This is a default definition which should work for most targets.
 595
 596 template<int size, bool big_endian, int sh_type>
 597 void
 598 relocate_relocs(
 599     const Relocate_info<size, big_endian>* relinfo,
 600     const unsigned char* prelocs,
 601     size_t reloc_count,
 602     Output_section* output_section,
 603     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 604     const Relocatable_relocs* rr,
 605     unsigned char* view,
 606     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 607     section_size_type view_size,
 608     unsigned char* reloc_view,
 609     section_size_type reloc_view_size)
 610 {
 611   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 612   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 613   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
 614     Reltype_write;
 615   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 616   const Address invalid_address = static_cast<Address>(0) - 1;
 617
 618   Sized_relobj_file<size, big_endian>* const object = relinfo->object;
 619   const unsigned int local_count = object->local_symbol_count();
 620
 621   unsigned char* pwrite = reloc_view;
 622
 623   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 624     {
 625       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
 626       if (strategy == Relocatable_relocs::RELOC_DISCARD)
 627         continue;
 628
 629       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
 630         {
 631           // Target wants to handle this relocation.
 632           Sized_target<size, big_endian>* target =
 633             parameters->sized_target<size, big_endian>();
 634           target->relocate_special_relocatable(relinfo, sh_type, prelocs,
 635                                                i, output_section,
 636                                                offset_in_output_section,
 637                                                view, view_address,
 638                                                view_size, pwrite);
 639           pwrite += reloc_size;
 640           continue;
 641         }
 642       Reltype reloc(prelocs);
 643       Reltype_write reloc_write(pwrite);
 644
 645       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 646       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 647       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 648
 649       // Get the new symbol index.
 650
 651       unsigned int new_symndx;
 652       if (r_sym < local_count)
 653         {
 654           switch (strategy)
 655             {
 656             case Relocatable_relocs::RELOC_COPY:
 657               if (r_sym == 0)
 658                 new_symndx = 0;
 659               else
 660                 {
 661                   new_symndx = object->symtab_index(r_sym);
 662                   gold_assert(new_symndx != -1U);
 663                 }
 664               break;
 665
 666             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 667             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 668             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 669             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 670             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 671             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 672             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 673               {
 674                 // We are adjusting a section symbol.  We need to find
 675                 // the symbol table index of the section symbol for
 676                 // the output section corresponding to input section
 677                 // in which this symbol is defined.
 678                 gold_assert(r_sym < local_count);
 679                 bool is_ordinary;
 680                 unsigned int shndx =
 681                   object->local_symbol_input_shndx(r_sym, &is_ordinary);
 682                 gold_assert(is_ordinary);
 683                 Output_section* os = object->output_section(shndx);
 684                 gold_assert(os != NULL);
 685                 gold_assert(os->needs_symtab_index());
 686                 new_symndx = os->symtab_index();
 687               }
 688               break;
 689
 690             default:
 691               gold_unreachable();
 692             }
 693         }
 694       else
 695         {
 696           const Symbol* gsym = object->global_symbol(r_sym);
 697           gold_assert(gsym != NULL);
 698           if (gsym->is_forwarder())
 699             gsym = relinfo->symtab->resolve_forwards(gsym);
 700
 701           gold_assert(gsym->has_symtab_index());
 702           new_symndx = gsym->symtab_index();
 703         }
 704
 705       // Get the new offset--the location in the output section where
 706       // this relocation should be applied.
 707
 708       Address offset = reloc.get_r_offset();
 709       Address new_offset;
 710       if (offset_in_output_section != invalid_address)
 711         new_offset = offset + offset_in_output_section;
 712       else
 713         {
 714           section_offset_type sot_offset =
 715               convert_types<section_offset_type, Address>(offset);
 716           section_offset_type new_sot_offset =
 717               output_section->output_offset(object, relinfo->data_shndx,
 718                                             sot_offset);
 719           gold_assert(new_sot_offset != -1);
 720           new_offset = new_sot_offset;
 721         }
 722
 723       // In an object file, r_offset is an offset within the section.
 724       // In an executable or dynamic object, generated by
 725       // --emit-relocs, r_offset is an absolute address.
 726       if (!parameters->options().relocatable())
 727         {
 728           new_offset += view_address;
 729           if (offset_in_output_section != invalid_address)
 730             new_offset -= offset_in_output_section;
 731         }
 732
 733       reloc_write.put_r_offset(new_offset);
 734       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
 735
 736       // Handle the reloc addend based on the strategy.
 737
 738       if (strategy == Relocatable_relocs::RELOC_COPY)
 739         {
 740           if (sh_type == elfcpp::SHT_RELA)
 741             Reloc_types<sh_type, size, big_endian>::
 742               copy_reloc_addend(&reloc_write,
 743                                 &reloc);
 744         }
 745       else
 746         {
 747           // The relocation uses a section symbol in the input file.
 748           // We are adjusting it to use a section symbol in the output
 749           // file.  The input section symbol refers to some address in
 750           // the input section.  We need the relocation in the output
 751           // file to refer to that same address.  This adjustment to
 752           // the addend is the same calculation we use for a simple
 753           // absolute relocation for the input section symbol.
 754
 755           const Symbol_value<size>* psymval = object->local_symbol(r_sym);
 756
 757           unsigned char* padd = view + offset;
 758           switch (strategy)
 759             {
 760             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 761               {
 762                 typename elfcpp::Elf_types<size>::Elf_Swxword addend;
 763                 addend = Reloc_types<sh_type, size, big_endian>::
 764                            get_reloc_addend(&reloc);
 765                 addend = psymval->value(object, addend);
 766                 Reloc_types<sh_type, size, big_endian>::
 767                   set_reloc_addend(&reloc_write, addend);
 768               }
 769               break;
 770
 771             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 772               break;
 773
 774             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 775               Relocate_functions<size, big_endian>::rel8(padd, object,
 776                                                          psymval);
 777               break;
 778
 779             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 780               Relocate_functions<size, big_endian>::rel16(padd, object,
 781                                                           psymval);
 782               break;
 783
 784             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 785               Relocate_functions<size, big_endian>::rel32(padd, object,
 786                                                           psymval);
 787               break;
 788
 789             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 790               Relocate_functions<size, big_endian>::rel64(padd, object,
 791                                                           psymval);
 792               break;
 793
 794             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 795               Relocate_functions<size, big_endian>::rel32_unaligned(padd,
 796                                                                     object,
 797                                                                     psymval);
 798               break;
 799
 800             default:
 801               gold_unreachable();
 802             }
 803         }
 804
 805       pwrite += reloc_size;
 806     }
 807
 808   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
 809               == reloc_view_size);
 810 }
 811
 812 } // End namespace gold.
 813
 814 #endif // !defined(GOLD_TARGET_RELOC_H)