gold/target-reloc.h

   1 // target-reloc.h -- target specific relocation support  -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
   4 // Free Software Foundation, Inc.
   5 // Written by Ian Lance Taylor <iant@google.com>.
   6
   7 // This file is part of gold.
   8
   9 // This program is free software; you can redistribute it and/or modify
  10 // it under the terms of the GNU General Public License as published by
  11 // the Free Software Foundation; either version 3 of the License, or
  12 // (at your option) any later version.
  13
  14 // This program is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18
  19 // You should have received a copy of the GNU General Public License
  20 // along with this program; if not, write to the Free Software
  21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  22 // MA 02110-1301, USA.
  23
  24 #ifndef GOLD_TARGET_RELOC_H
  25 #define GOLD_TARGET_RELOC_H
  26
  27 #include "elfcpp.h"
  28 #include "symtab.h"
  29 #include "object.h"
  30 #include "reloc.h"
  31 #include "reloc-types.h"
  32
  33 namespace gold
  34 {
  35
  36 // This function implements the generic part of reloc scanning.  The
  37 // template parameter Scan must be a class type which provides two
  38 // functions: local() and global().  Those functions implement the
  39 // machine specific part of scanning.  We do it this way to
  40 // avoid making a function call for each relocation, and to avoid
  41 // repeating the generic code for each target.
  42
  43 template<int size, bool big_endian, typename Target_type, int sh_type,
  44          typename Scan>
  45 inline void
  46 scan_relocs(
  47     Symbol_table* symtab,
  48     Layout* layout,
  49     Target_type* target,
  50     Sized_relobj_file<size, big_endian>* object,
  51     unsigned int data_shndx,
  52     const unsigned char* prelocs,
  53     size_t reloc_count,
  54     Output_section* output_section,
  55     bool needs_special_offset_handling,
  56     size_t local_count,
  57     const unsigned char* plocal_syms)
  58 {
  59   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
  60   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
  61   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
  62   Scan scan;
  63
  64   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
  65     {
  66       Reltype reloc(prelocs);
  67
  68       if (needs_special_offset_handling
  69           && !output_section->is_input_address_mapped(object, data_shndx,
  70                                                       reloc.get_r_offset()))
  71         continue;
  72
  73       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
  74       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
  75       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
  76
  77       if (r_sym < local_count)
  78         {
  79           gold_assert(plocal_syms != NULL);
  80           typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
  81                                                       + r_sym * sym_size);
  82           unsigned int shndx = lsym.get_st_shndx();
  83           bool is_ordinary;
  84           shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
  85           if (is_ordinary
  86               && shndx != elfcpp::SHN_UNDEF
  87               && !object->is_section_included(shndx)
  88               && !symtab->is_section_folded(object, shndx))
  89             {
  90               // RELOC is a relocation against a local symbol in a
  91               // section we are discarding.  We can ignore this
  92               // relocation.  It will eventually become a reloc
  93               // against the value zero.
  94               //
  95               // FIXME: We should issue a warning if this is an
  96               // allocated section; is this the best place to do it?
  97               //
  98               // FIXME: The old GNU linker would in some cases look
  99               // for the linkonce section which caused this section to
 100               // be discarded, and, if the other section was the same
 101               // size, change the reloc to refer to the other section.
 102               // That seems risky and weird to me, and I don't know of
 103               // any case where it is actually required.
 104
 105               continue;
 106             }
 107           scan.local(symtab, layout, target, object, data_shndx,
 108                      output_section, reloc, r_type, lsym);
 109         }
 110       else
 111         {
 112           Symbol* gsym = object->global_symbol(r_sym);
 113           gold_assert(gsym != NULL);
 114           if (gsym->is_forwarder())
 115             gsym = symtab->resolve_forwards(gsym);
 116
 117           scan.global(symtab, layout, target, object, data_shndx,
 118                       output_section, reloc, r_type, gsym);
 119         }
 120     }
 121 }
 122
 123 // Behavior for relocations to discarded comdat sections.
 124
 125 enum Comdat_behavior
 126 {
 127   CB_UNDETERMINED,   // Not yet determined -- need to look at section name.
 128   CB_PRETEND,        // Attempt to map to the corresponding kept section.
 129   CB_IGNORE,         // Ignore the relocation.
 130   CB_WARNING         // Print a warning.
 131 };
 132
 133 // Decide what the linker should do for relocations that refer to discarded
 134 // comdat sections.  This decision is based on the name of the section being
 135 // relocated.
 136
 137 inline Comdat_behavior
 138 get_comdat_behavior(const char* name)
 139 {
 140   if (Layout::is_debug_info_section(name))
 141     return CB_PRETEND;
 142   if (strcmp(name, ".eh_frame") == 0
 143       || strcmp(name, ".gcc_except_table") == 0)
 144     return CB_IGNORE;
 145   return CB_WARNING;
 146 }
 147
 148 // Give an error for a symbol with non-default visibility which is not
 149 // defined locally.
 150
 151 inline void
 152 visibility_error(const Symbol* sym)
 153 {
 154   const char* v;
 155   switch (sym->visibility())
 156     {
 157     case elfcpp::STV_INTERNAL:
 158       v = _("internal");
 159       break;
 160     case elfcpp::STV_HIDDEN:
 161       v = _("hidden");
 162       break;
 163     case elfcpp::STV_PROTECTED:
 164       v = _("protected");
 165       break;
 166     default:
 167       gold_unreachable();
 168     }
 169   gold_error(_("%s symbol '%s' is not defined locally"),
 170              v, sym->name());
 171 }
 172
 173 // Return true if we are should issue an error saying that SYM is an
 174 // undefined symbol.  This is called if there is a relocation against
 175 // SYM.
 176
 177 inline bool
 178 issue_undefined_symbol_error(const Symbol* sym)
 179 {
 180   // We only report global symbols.
 181   if (sym == NULL)
 182     return false;
 183
 184   // We only report undefined symbols.
 185   if (!sym->is_undefined() && !sym->is_placeholder())
 186     return false;
 187
 188   // We don't report weak symbols.
 189   if (sym->binding() == elfcpp::STB_WEAK)
 190     return false;
 191
 192   // We don't report symbols defined in discarded sections.
 193   if (sym->is_defined_in_discarded_section())
 194     return false;
 195
 196   // If the target defines this symbol, don't report it here.
 197   if (parameters->target().is_defined_by_abi(sym))
 198     return false;
 199
 200   // See if we've been told to ignore whether this symbol is
 201   // undefined.
 202   const char* const u = parameters->options().unresolved_symbols();
 203   if (u != NULL)
 204     {
 205       if (strcmp(u, "ignore-all") == 0)
 206         return false;
 207       if (strcmp(u, "report-all") == 0)
 208         return true;
 209       if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn())
 210         return false;
 211       if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg())
 212         return false;
 213     }
 214
 215   // When creating a shared library, only report unresolved symbols if
 216   // -z defs was used.
 217   if (parameters->options().shared() && !parameters->options().defs())
 218     return false;
 219
 220   // Otherwise issue a warning.
 221   return true;
 222 }
 223
 224 // This function implements the generic part of relocation processing.
 225 // The template parameter Relocate must be a class type which provides
 226 // a single function, relocate(), which implements the machine
 227 // specific part of a relocation.
 228
 229 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 230 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 231 // RELOCATE implements operator() to do a relocation.
 232
 233 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 234 // of relocs.  OUTPUT_SECTION is the output section.
 235 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
 236 // mapped to output offsets.
 237
 238 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
 239 // VIEW_SIZE is the size.  These refer to the input section, unless
 240 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
 241 // the output section.
 242
 243 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
 244 // not NULL, it is a vector indexed by relocation index.  If that
 245 // entry is not NULL, it points to a global symbol which used as the
 246 // symbol for the relocation, ignoring the symbol index in the
 247 // relocation.
 248
 249 template<int size, bool big_endian, typename Target_type, int sh_type,
 250          typename Relocate>
 251 inline void
 252 relocate_section(
 253     const Relocate_info<size, big_endian>* relinfo,
 254     Target_type* target,
 255     const unsigned char* prelocs,
 256     size_t reloc_count,
 257     Output_section* output_section,
 258     bool needs_special_offset_handling,
 259     unsigned char* view,
 260     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 261     section_size_type view_size,
 262     const Reloc_symbol_changes* reloc_symbol_changes)
 263 {
 264   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 265   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 266   Relocate relocate;
 267
 268   Sized_relobj_file<size, big_endian>* object = relinfo->object;
 269   unsigned int local_count = object->local_symbol_count();
 270
 271   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
 272
 273   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 274     {
 275       Reltype reloc(prelocs);
 276
 277       section_offset_type offset =
 278         convert_to_section_size_type(reloc.get_r_offset());
 279
 280       if (needs_special_offset_handling)
 281         {
 282           offset = output_section->output_offset(relinfo->object,
 283                                                  relinfo->data_shndx,
 284                                                  offset);
 285           if (offset == -1)
 286             continue;
 287         }
 288
 289       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 290       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 291       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 292
 293       const Sized_symbol<size>* sym;
 294
 295       Symbol_value<size> symval;
 296       const Symbol_value<size> *psymval;
 297       bool is_defined_in_discarded_section;
 298       unsigned int shndx;
 299       if (r_sym < local_count
 300           && (reloc_symbol_changes == NULL
 301               || (*reloc_symbol_changes)[i] == NULL))
 302         {
 303           sym = NULL;
 304           psymval = object->local_symbol(r_sym);
 305
 306           // If the local symbol belongs to a section we are discarding,
 307           // and that section is a debug section, try to find the
 308           // corresponding kept section and map this symbol to its
 309           // counterpart in the kept section.  The symbol must not
 310           // correspond to a section we are folding.
 311           bool is_ordinary;
 312           shndx = psymval->input_shndx(&is_ordinary);
 313           is_defined_in_discarded_section =
 314             (is_ordinary
 315              && shndx != elfcpp::SHN_UNDEF
 316              && !object->is_section_included(shndx)
 317              && !relinfo->symtab->is_section_folded(object, shndx));
 318         }
 319       else
 320         {
 321           const Symbol* gsym;
 322           if (reloc_symbol_changes != NULL
 323               && (*reloc_symbol_changes)[i] != NULL)
 324             gsym = (*reloc_symbol_changes)[i];
 325           else
 326             {
 327               gsym = object->global_symbol(r_sym);
 328               gold_assert(gsym != NULL);
 329               if (gsym->is_forwarder())
 330                 gsym = relinfo->symtab->resolve_forwards(gsym);
 331             }
 332
 333           sym = static_cast<const Sized_symbol<size>*>(gsym);
 334           if (sym->has_symtab_index() && sym->symtab_index() != -1U)
 335             symval.set_output_symtab_index(sym->symtab_index());
 336           else
 337             symval.set_no_output_symtab_entry();
 338           symval.set_output_value(sym->value());
 339           if (gsym->type() == elfcpp::STT_TLS)
 340             symval.set_is_tls_symbol();
 341           else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 342             symval.set_is_ifunc_symbol();
 343           psymval = &symval;
 344
 345           is_defined_in_discarded_section =
 346             (gsym->is_defined_in_discarded_section()
 347              && gsym->is_undefined());
 348           shndx = 0;
 349         }
 350
 351       Symbol_value<size> symval2;
 352       if (is_defined_in_discarded_section)
 353         {
 354           if (comdat_behavior == CB_UNDETERMINED)
 355             {
 356               std::string name = object->section_name(relinfo->data_shndx);
 357               comdat_behavior = get_comdat_behavior(name.c_str());
 358             }
 359           if (comdat_behavior == CB_PRETEND)
 360             {
 361               // FIXME: This case does not work for global symbols.
 362               // We have no place to store the original section index.
 363               // Fortunately this does not matter for comdat sections,
 364               // only for sections explicitly discarded by a linker
 365               // script.
 366               bool found;
 367               typename elfcpp::Elf_types<size>::Elf_Addr value =
 368                 object->map_to_kept_section(shndx, &found);
 369               if (found)
 370                 symval2.set_output_value(value + psymval->input_value());
 371               else
 372                 symval2.set_output_value(0);
 373             }
 374           else
 375             {
 376               if (comdat_behavior == CB_WARNING)
 377                 gold_warning_at_location(relinfo, i, offset,
 378                                          _("relocation refers to discarded "
 379                                            "section"));
 380               symval2.set_output_value(0);
 381             }
 382           symval2.set_no_output_symtab_entry();
 383           psymval = &symval2;
 384         }
 385
 386       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
 387                              r_type, sym, psymval, view + offset,
 388                              view_address + offset, view_size))
 389         continue;
 390
 391       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
 392         {
 393           gold_error_at_location(relinfo, i, offset,
 394                                  _("reloc has bad offset %zu"),
 395                                  static_cast<size_t>(offset));
 396           continue;
 397         }
 398
 399       if (issue_undefined_symbol_error(sym))
 400         gold_undefined_symbol_at_location(sym, relinfo, i, offset);
 401       else if (sym != NULL
 402                && sym->visibility() != elfcpp::STV_DEFAULT
 403                && (sym->is_undefined() || sym->is_from_dynobj()))
 404         visibility_error(sym);
 405
 406       if (sym != NULL && sym->has_warning())
 407         relinfo->symtab->issue_warning(sym, relinfo, i, offset);
 408     }
 409 }
 410
 411 // Apply an incremental relocation.
 412
 413 template<int size, bool big_endian, typename Target_type,
 414          typename Relocate>
 415 void
 416 apply_relocation(const Relocate_info<size, big_endian>* relinfo,
 417                  Target_type* target,
 418                  typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
 419                  unsigned int r_type,
 420                  typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
 421                  const Symbol* gsym,
 422                  unsigned char* view,
 423                  typename elfcpp::Elf_types<size>::Elf_Addr address,
 424                  section_size_type view_size)
 425 {
 426   // Construct the ELF relocation in a temporary buffer.
 427   const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 428   unsigned char relbuf[reloc_size];
 429   elfcpp::Rela<size, big_endian> rel(relbuf);
 430   elfcpp::Rela_write<size, big_endian> orel(relbuf);
 431   orel.put_r_offset(r_offset);
 432   orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type));
 433   orel.put_r_addend(r_addend);
 434
 435   // Setup a Symbol_value for the global symbol.
 436   const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym);
 437   Symbol_value<size> symval;
 438   gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U);
 439   symval.set_output_symtab_index(sym->symtab_index());
 440   symval.set_output_value(sym->value());
 441   if (gsym->type() == elfcpp::STT_TLS)
 442     symval.set_is_tls_symbol();
 443   else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 444     symval.set_is_ifunc_symbol();
 445
 446   Relocate relocate;
 447   relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval,
 448                     view + r_offset, address + r_offset, view_size);
 449 }
 450
 451 // This class may be used as a typical class for the
 452 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
 453 // template parameter Classify_reloc must be a class type which
 454 // provides a function get_size_for_reloc which returns the number of
 455 // bytes to which a reloc applies.  This class is intended to capture
 456 // the most typical target behaviour, while still permitting targets
 457 // to define their own independent class for Scan_relocatable_reloc.
 458
 459 template<int sh_type, typename Classify_reloc>
 460 class Default_scan_relocatable_relocs
 461 {
 462  public:
 463   // Return the strategy to use for a local symbol which is not a
 464   // section symbol, given the relocation type.
 465   inline Relocatable_relocs::Reloc_strategy
 466   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
 467   {
 468     // We assume that relocation type 0 is NONE.  Targets which are
 469     // different must override.
 470     if (r_type == 0 && r_sym == 0)
 471       return Relocatable_relocs::RELOC_DISCARD;
 472     return Relocatable_relocs::RELOC_COPY;
 473   }
 474
 475   // Return the strategy to use for a local symbol which is a section
 476   // symbol, given the relocation type.
 477   inline Relocatable_relocs::Reloc_strategy
 478   local_section_strategy(unsigned int r_type, Relobj* object)
 479   {
 480     if (sh_type == elfcpp::SHT_RELA)
 481       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 482     else
 483       {
 484         Classify_reloc classify;
 485         switch (classify.get_size_for_reloc(r_type, object))
 486           {
 487           case 0:
 488             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 489           case 1:
 490             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
 491           case 2:
 492             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
 493           case 4:
 494             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
 495           case 8:
 496             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
 497           default:
 498             gold_unreachable();
 499           }
 500       }
 501   }
 502
 503   // Return the strategy to use for a global symbol, given the
 504   // relocation type, the object, and the symbol index.
 505   inline Relocatable_relocs::Reloc_strategy
 506   global_strategy(unsigned int, Relobj*, unsigned int)
 507   { return Relocatable_relocs::RELOC_COPY; }
 508 };
 509
 510 // Scan relocs during a relocatable link.  This is a default
 511 // definition which should work for most targets.
 512 // Scan_relocatable_reloc must name a class type which provides three
 513 // functions which return a Relocatable_relocs::Reloc_strategy code:
 514 // global_strategy, local_non_section_strategy, and
 515 // local_section_strategy.  Most targets should be able to use
 516 // Default_scan_relocatable_relocs as this class.
 517
 518 template<int size, bool big_endian, int sh_type,
 519          typename Scan_relocatable_reloc>
 520 void
 521 scan_relocatable_relocs(
 522     Symbol_table*,
 523     Layout*,
 524     Sized_relobj_file<size, big_endian>* object,
 525     unsigned int data_shndx,
 526     const unsigned char* prelocs,
 527     size_t reloc_count,
 528     Output_section* output_section,
 529     bool needs_special_offset_handling,
 530     size_t local_symbol_count,
 531     const unsigned char* plocal_syms,
 532     Relocatable_relocs* rr)
 533 {
 534   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 535   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 536   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 537   Scan_relocatable_reloc scan;
 538
 539   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 540     {
 541       Reltype reloc(prelocs);
 542
 543       Relocatable_relocs::Reloc_strategy strategy;
 544
 545       if (needs_special_offset_handling
 546           && !output_section->is_input_address_mapped(object, data_shndx,
 547                                                       reloc.get_r_offset()))
 548         strategy = Relocatable_relocs::RELOC_DISCARD;
 549       else
 550         {
 551           typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 552             reloc.get_r_info();
 553           const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 554           const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 555
 556           if (r_sym >= local_symbol_count)
 557             strategy = scan.global_strategy(r_type, object, r_sym);
 558           else
 559             {
 560               gold_assert(plocal_syms != NULL);
 561               typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
 562                                                           + r_sym * sym_size);
 563               unsigned int shndx = lsym.get_st_shndx();
 564               bool is_ordinary;
 565               shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
 566               if (is_ordinary
 567                   && shndx != elfcpp::SHN_UNDEF
 568                   && !object->is_section_included(shndx))
 569                 {
 570                   // RELOC is a relocation against a local symbol
 571                   // defined in a section we are discarding.  Discard
 572                   // the reloc.  FIXME: Should we issue a warning?
 573                   strategy = Relocatable_relocs::RELOC_DISCARD;
 574                 }
 575               else if (lsym.get_st_type() != elfcpp::STT_SECTION)
 576                 strategy = scan.local_non_section_strategy(r_type, object,
 577                                                            r_sym);
 578               else
 579                 {
 580                   strategy = scan.local_section_strategy(r_type, object);
 581                   if (strategy != Relocatable_relocs::RELOC_DISCARD)
 582                     object->output_section(shndx)->set_needs_symtab_index();
 583                 }
 584
 585               if (strategy == Relocatable_relocs::RELOC_COPY)
 586                 object->set_must_have_output_symtab_entry(r_sym);
 587             }
 588         }
 589
 590       rr->set_next_reloc_strategy(strategy);
 591     }
 592 }
 593
 594 // Relocate relocs during a relocatable link.  This is a default
 595 // definition which should work for most targets.
 596
 597 template<int size, bool big_endian, int sh_type>
 598 void
 599 relocate_for_relocatable(
 600     const Relocate_info<size, big_endian>* relinfo,
 601     const unsigned char* prelocs,
 602     size_t reloc_count,
 603     Output_section* output_section,
 604     typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
 605     const Relocatable_relocs* rr,
 606     unsigned char* view,
 607     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 608     section_size_type view_size,
 609     unsigned char* reloc_view,
 610     section_size_type reloc_view_size)
 611 {
 612   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 613   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 614   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
 615     Reltype_write;
 616   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 617   const Address invalid_address = static_cast<Address>(0) - 1;
 618
 619   Sized_relobj_file<size, big_endian>* const object = relinfo->object;
 620   const unsigned int local_count = object->local_symbol_count();
 621
 622   unsigned char* pwrite = reloc_view;
 623
 624   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 625     {
 626       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
 627       if (strategy == Relocatable_relocs::RELOC_DISCARD)
 628         continue;
 629
 630       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
 631         {
 632           // Target wants to handle this relocation.
 633           Sized_target<size, big_endian>* target =
 634             parameters->sized_target<size, big_endian>();
 635           target->relocate_special_relocatable(relinfo, sh_type, prelocs,
 636                                                i, output_section,
 637                                                offset_in_output_section,
 638                                                view, view_address,
 639                                                view_size, pwrite);
 640           pwrite += reloc_size;
 641           continue;
 642         }
 643       Reltype reloc(prelocs);
 644       Reltype_write reloc_write(pwrite);
 645
 646       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 647       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 648       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 649
 650       // Get the new symbol index.
 651
 652       unsigned int new_symndx;
 653       if (r_sym < local_count)
 654         {
 655           switch (strategy)
 656             {
 657             case Relocatable_relocs::RELOC_COPY:
 658               if (r_sym == 0)
 659                 new_symndx = 0;
 660               else
 661                 {
 662                   new_symndx = object->symtab_index(r_sym);
 663                   gold_assert(new_symndx != -1U);
 664                 }
 665               break;
 666
 667             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 668             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 669             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 670             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 671             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 672             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 673             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 674               {
 675                 // We are adjusting a section symbol.  We need to find
 676                 // the symbol table index of the section symbol for
 677                 // the output section corresponding to input section
 678                 // in which this symbol is defined.
 679                 gold_assert(r_sym < local_count);
 680                 bool is_ordinary;
 681                 unsigned int shndx =
 682                   object->local_symbol_input_shndx(r_sym, &is_ordinary);
 683                 gold_assert(is_ordinary);
 684                 Output_section* os = object->output_section(shndx);
 685                 gold_assert(os != NULL);
 686                 gold_assert(os->needs_symtab_index());
 687                 new_symndx = os->symtab_index();
 688               }
 689               break;
 690
 691             default:
 692               gold_unreachable();
 693             }
 694         }
 695       else
 696         {
 697           const Symbol* gsym = object->global_symbol(r_sym);
 698           gold_assert(gsym != NULL);
 699           if (gsym->is_forwarder())
 700             gsym = relinfo->symtab->resolve_forwards(gsym);
 701
 702           gold_assert(gsym->has_symtab_index());
 703           new_symndx = gsym->symtab_index();
 704         }
 705
 706       // Get the new offset--the location in the output section where
 707       // this relocation should be applied.
 708
 709       Address offset = reloc.get_r_offset();
 710       Address new_offset;
 711       if (offset_in_output_section != invalid_address)
 712         new_offset = offset + offset_in_output_section;
 713       else
 714         {
 715           section_offset_type sot_offset =
 716               convert_types<section_offset_type, Address>(offset);
 717           section_offset_type new_sot_offset =
 718               output_section->output_offset(object, relinfo->data_shndx,
 719                                             sot_offset);
 720           gold_assert(new_sot_offset != -1);
 721           new_offset = new_sot_offset;
 722         }
 723
 724       // In an object file, r_offset is an offset within the section.
 725       // In an executable or dynamic object, generated by
 726       // --emit-relocs, r_offset is an absolute address.
 727       if (!parameters->options().relocatable())
 728         {
 729           new_offset += view_address;
 730           if (offset_in_output_section != invalid_address)
 731             new_offset -= offset_in_output_section;
 732         }
 733
 734       reloc_write.put_r_offset(new_offset);
 735       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
 736
 737       // Handle the reloc addend based on the strategy.
 738
 739       if (strategy == Relocatable_relocs::RELOC_COPY)
 740         {
 741           if (sh_type == elfcpp::SHT_RELA)
 742             Reloc_types<sh_type, size, big_endian>::
 743               copy_reloc_addend(&reloc_write,
 744                                 &reloc);
 745         }
 746       else
 747         {
 748           // The relocation uses a section symbol in the input file.
 749           // We are adjusting it to use a section symbol in the output
 750           // file.  The input section symbol refers to some address in
 751           // the input section.  We need the relocation in the output
 752           // file to refer to that same address.  This adjustment to
 753           // the addend is the same calculation we use for a simple
 754           // absolute relocation for the input section symbol.
 755
 756           const Symbol_value<size>* psymval = object->local_symbol(r_sym);
 757
 758           unsigned char* padd = view + offset;
 759           switch (strategy)
 760             {
 761             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 762               {
 763                 typename elfcpp::Elf_types<size>::Elf_Swxword addend;
 764                 addend = Reloc_types<sh_type, size, big_endian>::
 765                            get_reloc_addend(&reloc);
 766                 addend = psymval->value(object, addend);
 767                 Reloc_types<sh_type, size, big_endian>::
 768                   set_reloc_addend(&reloc_write, addend);
 769               }
 770               break;
 771
 772             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 773               break;
 774
 775             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 776               Relocate_functions<size, big_endian>::rel8(padd, object,
 777                                                          psymval);
 778               break;
 779
 780             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 781               Relocate_functions<size, big_endian>::rel16(padd, object,
 782                                                           psymval);
 783               break;
 784
 785             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 786               Relocate_functions<size, big_endian>::rel32(padd, object,
 787                                                           psymval);
 788               break;
 789
 790             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 791               Relocate_functions<size, big_endian>::rel64(padd, object,
 792                                                           psymval);
 793               break;
 794
 795             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 796               Relocate_functions<size, big_endian>::rel32_unaligned(padd,
 797                                                                     object,
 798                                                                     psymval);
 799               break;
 800
 801             default:
 802               gold_unreachable();
 803             }
 804         }
 805
 806       pwrite += reloc_size;
 807     }
 808
 809   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
 810               == reloc_view_size);
 811 }
 812
 813 } // End namespace gold.
 814
 815 #endif // !defined(GOLD_TARGET_RELOC_H)