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