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 class Default_comdat_behavior
 128 {
 129  public:
 130   // Decide what the linker should do for relocations that refer to
 131   // discarded comdat sections.  This decision is based on the name of
 132   // the section being relocated.
 133
 134   inline Comdat_behavior
 135   get(const char* name)
 136   {
 137     if (Layout::is_debug_info_section(name))
 138       return CB_PRETEND;
 139     if (strcmp(name, ".eh_frame") == 0
 140         || strcmp(name, ".gcc_except_table") == 0)
 141       return CB_IGNORE;
 142     return CB_WARNING;
 143   }
 144 };
 145
 146 // Give an error for a symbol with non-default visibility which is not
 147 // defined locally.
 148
 149 inline void
 150 visibility_error(const Symbol* sym)
 151 {
 152   const char* v;
 153   switch (sym->visibility())
 154     {
 155     case elfcpp::STV_INTERNAL:
 156       v = _("internal");
 157       break;
 158     case elfcpp::STV_HIDDEN:
 159       v = _("hidden");
 160       break;
 161     case elfcpp::STV_PROTECTED:
 162       v = _("protected");
 163       break;
 164     default:
 165       gold_unreachable();
 166     }
 167   gold_error(_("%s symbol '%s' is not defined locally"),
 168              v, sym->name());
 169 }
 170
 171 // Return true if we are should issue an error saying that SYM is an
 172 // undefined symbol.  This is called if there is a relocation against
 173 // SYM.
 174
 175 inline bool
 176 issue_undefined_symbol_error(const Symbol* sym)
 177 {
 178   // We only report global symbols.
 179   if (sym == NULL)
 180     return false;
 181
 182   // We only report undefined symbols.
 183   if (!sym->is_undefined() && !sym->is_placeholder())
 184     return false;
 185
 186   // We don't report weak symbols.
 187   if (sym->binding() == elfcpp::STB_WEAK)
 188     return false;
 189
 190   // We don't report symbols defined in discarded sections.
 191   if (sym->is_defined_in_discarded_section())
 192     return false;
 193
 194   // If the target defines this symbol, don't report it here.
 195   if (parameters->target().is_defined_by_abi(sym))
 196     return false;
 197
 198   // See if we've been told to ignore whether this symbol is
 199   // undefined.
 200   const char* const u = parameters->options().unresolved_symbols();
 201   if (u != NULL)
 202     {
 203       if (strcmp(u, "ignore-all") == 0)
 204         return false;
 205       if (strcmp(u, "report-all") == 0)
 206         return true;
 207       if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn())
 208         return false;
 209       if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg())
 210         return false;
 211     }
 212
 213   // When creating a shared library, only report unresolved symbols if
 214   // -z defs was used.
 215   if (parameters->options().shared() && !parameters->options().defs())
 216     return false;
 217
 218   // Otherwise issue a warning.
 219   return true;
 220 }
 221
 222 // This function implements the generic part of relocation processing.
 223 // The template parameter Relocate must be a class type which provides
 224 // a single function, relocate(), which implements the machine
 225 // specific part of a relocation.
 226
 227 // The template parameter Relocate_comdat_behavior is a class type
 228 // which provides a single function, get(), which determines what the
 229 // linker should do for relocations that refer to discarded comdat
 230 // sections.
 231
 232 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 233 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 234 // RELOCATE implements operator() to do a relocation.
 235
 236 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 237 // of relocs.  OUTPUT_SECTION is the output section.
 238 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
 239 // mapped to output offsets.
 240
 241 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
 242 // VIEW_SIZE is the size.  These refer to the input section, unless
 243 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
 244 // the output section.
 245
 246 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
 247 // not NULL, it is a vector indexed by relocation index.  If that
 248 // entry is not NULL, it points to a global symbol which used as the
 249 // symbol for the relocation, ignoring the symbol index in the
 250 // relocation.
 251
 252 template<int size, bool big_endian, typename Target_type, int sh_type,
 253          typename Relocate,
 254          typename Relocate_comdat_behavior>
 255 inline void
 256 relocate_section(
 257     const Relocate_info<size, big_endian>* relinfo,
 258     Target_type* target,
 259     const unsigned char* prelocs,
 260     size_t reloc_count,
 261     Output_section* output_section,
 262     bool needs_special_offset_handling,
 263     unsigned char* view,
 264     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 265     section_size_type view_size,
 266     const Reloc_symbol_changes* reloc_symbol_changes)
 267 {
 268   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 269   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 270   Relocate relocate;
 271   Relocate_comdat_behavior relocate_comdat_behavior;
 272
 273   Sized_relobj_file<size, big_endian>* object = relinfo->object;
 274   unsigned int local_count = object->local_symbol_count();
 275
 276   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
 277
 278   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 279     {
 280       Reltype reloc(prelocs);
 281
 282       section_offset_type offset =
 283         convert_to_section_size_type(reloc.get_r_offset());
 284
 285       if (needs_special_offset_handling)
 286         {
 287           offset = output_section->output_offset(relinfo->object,
 288                                                  relinfo->data_shndx,
 289                                                  offset);
 290           if (offset == -1)
 291             continue;
 292         }
 293
 294       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 295       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 296       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 297
 298       const Sized_symbol<size>* sym;
 299
 300       Symbol_value<size> symval;
 301       const Symbol_value<size> *psymval;
 302       bool is_defined_in_discarded_section;
 303       unsigned int shndx;
 304       if (r_sym < local_count
 305           && (reloc_symbol_changes == NULL
 306               || (*reloc_symbol_changes)[i] == NULL))
 307         {
 308           sym = NULL;
 309           psymval = object->local_symbol(r_sym);
 310
 311           // If the local symbol belongs to a section we are discarding,
 312           // and that section is a debug section, try to find the
 313           // corresponding kept section and map this symbol to its
 314           // counterpart in the kept section.  The symbol must not
 315           // correspond to a section we are folding.
 316           bool is_ordinary;
 317           shndx = psymval->input_shndx(&is_ordinary);
 318           is_defined_in_discarded_section =
 319             (is_ordinary
 320              && shndx != elfcpp::SHN_UNDEF
 321              && !object->is_section_included(shndx)
 322              && !relinfo->symtab->is_section_folded(object, shndx));
 323         }
 324       else
 325         {
 326           const Symbol* gsym;
 327           if (reloc_symbol_changes != NULL
 328               && (*reloc_symbol_changes)[i] != NULL)
 329             gsym = (*reloc_symbol_changes)[i];
 330           else
 331             {
 332               gsym = object->global_symbol(r_sym);
 333               gold_assert(gsym != NULL);
 334               if (gsym->is_forwarder())
 335                 gsym = relinfo->symtab->resolve_forwards(gsym);
 336             }
 337
 338           sym = static_cast<const Sized_symbol<size>*>(gsym);
 339           if (sym->has_symtab_index() && sym->symtab_index() != -1U)
 340             symval.set_output_symtab_index(sym->symtab_index());
 341           else
 342             symval.set_no_output_symtab_entry();
 343           symval.set_output_value(sym->value());
 344           if (gsym->type() == elfcpp::STT_TLS)
 345             symval.set_is_tls_symbol();
 346           else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 347             symval.set_is_ifunc_symbol();
 348           psymval = &symval;
 349
 350           is_defined_in_discarded_section =
 351             (gsym->is_defined_in_discarded_section()
 352              && gsym->is_undefined());
 353           shndx = 0;
 354         }
 355
 356       Symbol_value<size> symval2;
 357       if (is_defined_in_discarded_section)
 358         {
 359           if (comdat_behavior == CB_UNDETERMINED)
 360             {
 361               std::string name = object->section_name(relinfo->data_shndx);
 362               comdat_behavior = relocate_comdat_behavior.get(name.c_str());
 363             }
 364           if (comdat_behavior == CB_PRETEND)
 365             {
 366               // FIXME: This case does not work for global symbols.
 367               // We have no place to store the original section index.
 368               // Fortunately this does not matter for comdat sections,
 369               // only for sections explicitly discarded by a linker
 370               // script.
 371               bool found;
 372               typename elfcpp::Elf_types<size>::Elf_Addr value =
 373                 object->map_to_kept_section(shndx, &found);
 374               if (found)
 375                 symval2.set_output_value(value + psymval->input_value());
 376               else
 377                 symval2.set_output_value(0);
 378             }
 379           else
 380             {
 381               if (comdat_behavior == CB_WARNING)
 382                 gold_warning_at_location(relinfo, i, offset,
 383                                          _("relocation refers to discarded "
 384                                            "section"));
 385               symval2.set_output_value(0);
 386             }
 387           symval2.set_no_output_symtab_entry();
 388           psymval = &symval2;
 389         }
 390
 391       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
 392                              r_type, sym, psymval, view + offset,
 393                              view_address + offset, view_size))
 394         continue;
 395
 396       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
 397         {
 398           gold_error_at_location(relinfo, i, offset,
 399                                  _("reloc has bad offset %zu"),
 400                                  static_cast<size_t>(offset));
 401           continue;
 402         }
 403
 404       if (issue_undefined_symbol_error(sym))
 405         gold_undefined_symbol_at_location(sym, relinfo, i, offset);
 406       else if (sym != NULL
 407                && sym->visibility() != elfcpp::STV_DEFAULT
 408                && (sym->is_undefined() || sym->is_from_dynobj()))
 409         visibility_error(sym);
 410
 411       if (sym != NULL && sym->has_warning())
 412         relinfo->symtab->issue_warning(sym, relinfo, i, offset);
 413     }
 414 }
 415
 416 // Apply an incremental relocation.
 417
 418 template<int size, bool big_endian, typename Target_type,
 419          typename Relocate>
 420 void
 421 apply_relocation(const Relocate_info<size, big_endian>* relinfo,
 422                  Target_type* target,
 423                  typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
 424                  unsigned int r_type,
 425                  typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
 426                  const Symbol* gsym,
 427                  unsigned char* view,
 428                  typename elfcpp::Elf_types<size>::Elf_Addr address,
 429                  section_size_type view_size)
 430 {
 431   // Construct the ELF relocation in a temporary buffer.
 432   const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
 433   unsigned char relbuf[reloc_size];
 434   elfcpp::Rela<size, big_endian> rel(relbuf);
 435   elfcpp::Rela_write<size, big_endian> orel(relbuf);
 436   orel.put_r_offset(r_offset);
 437   orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type));
 438   orel.put_r_addend(r_addend);
 439
 440   // Setup a Symbol_value for the global symbol.
 441   const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym);
 442   Symbol_value<size> symval;
 443   gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U);
 444   symval.set_output_symtab_index(sym->symtab_index());
 445   symval.set_output_value(sym->value());
 446   if (gsym->type() == elfcpp::STT_TLS)
 447     symval.set_is_tls_symbol();
 448   else if (gsym->type() == elfcpp::STT_GNU_IFUNC)
 449     symval.set_is_ifunc_symbol();
 450
 451   Relocate relocate;
 452   relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval,
 453                     view + r_offset, address + r_offset, view_size);
 454 }
 455
 456 // This class may be used as a typical class for the
 457 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
 458 // template parameter Classify_reloc must be a class type which
 459 // provides a function get_size_for_reloc which returns the number of
 460 // bytes to which a reloc applies.  This class is intended to capture
 461 // the most typical target behaviour, while still permitting targets
 462 // to define their own independent class for Scan_relocatable_reloc.
 463
 464 template<int sh_type, typename Classify_reloc>
 465 class Default_scan_relocatable_relocs
 466 {
 467  public:
 468   // Return the strategy to use for a local symbol which is not a
 469   // section symbol, given the relocation type.
 470   inline Relocatable_relocs::Reloc_strategy
 471   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
 472   {
 473     // We assume that relocation type 0 is NONE.  Targets which are
 474     // different must override.
 475     if (r_type == 0 && r_sym == 0)
 476       return Relocatable_relocs::RELOC_DISCARD;
 477     return Relocatable_relocs::RELOC_COPY;
 478   }
 479
 480   // Return the strategy to use for a local symbol which is a section
 481   // symbol, given the relocation type.
 482   inline Relocatable_relocs::Reloc_strategy
 483   local_section_strategy(unsigned int r_type, Relobj* object)
 484   {
 485     if (sh_type == elfcpp::SHT_RELA)
 486       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 487     else
 488       {
 489         Classify_reloc classify;
 490         switch (classify.get_size_for_reloc(r_type, object))
 491           {
 492           case 0:
 493             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 494           case 1:
 495             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
 496           case 2:
 497             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
 498           case 4:
 499             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
 500           case 8:
 501             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
 502           default:
 503             gold_unreachable();
 504           }
 505       }
 506   }
 507
 508   // Return the strategy to use for a global symbol, given the
 509   // relocation type, the object, and the symbol index.
 510   inline Relocatable_relocs::Reloc_strategy
 511   global_strategy(unsigned int, Relobj*, unsigned int)
 512   { return Relocatable_relocs::RELOC_COPY; }
 513 };
 514
 515 // Scan relocs during a relocatable link.  This is a default
 516 // definition which should work for most targets.
 517 // Scan_relocatable_reloc must name a class type which provides three
 518 // functions which return a Relocatable_relocs::Reloc_strategy code:
 519 // global_strategy, local_non_section_strategy, and
 520 // local_section_strategy.  Most targets should be able to use
 521 // Default_scan_relocatable_relocs as this class.
 522
 523 template<int size, bool big_endian, int sh_type,
 524          typename Scan_relocatable_reloc>
 525 void
 526 scan_relocatable_relocs(
 527     Symbol_table*,
 528     Layout*,
 529     Sized_relobj_file<size, big_endian>* object,
 530     unsigned int data_shndx,
 531     const unsigned char* prelocs,
 532     size_t reloc_count,
 533     Output_section* output_section,
 534     bool needs_special_offset_handling,
 535     size_t local_symbol_count,
 536     const unsigned char* plocal_syms,
 537     Relocatable_relocs* rr)
 538 {
 539   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 540   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 541   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 542   Scan_relocatable_reloc scan;
 543
 544   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 545     {
 546       Reltype reloc(prelocs);
 547
 548       Relocatable_relocs::Reloc_strategy strategy;
 549
 550       if (needs_special_offset_handling
 551           && !output_section->is_input_address_mapped(object, data_shndx,
 552                                                       reloc.get_r_offset()))
 553         strategy = Relocatable_relocs::RELOC_DISCARD;
 554       else
 555         {
 556           typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 557             reloc.get_r_info();
 558           const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 559           const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 560
 561           if (r_sym >= local_symbol_count)
 562             strategy = scan.global_strategy(r_type, object, r_sym);
 563           else
 564             {
 565               gold_assert(plocal_syms != NULL);
 566               typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
 567                                                           + r_sym * sym_size);
 568               unsigned int shndx = lsym.get_st_shndx();
 569               bool is_ordinary;
 570               shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
 571               if (is_ordinary
 572                   && shndx != elfcpp::SHN_UNDEF
 573                   && !object->is_section_included(shndx))
 574                 {
 575                   // RELOC is a relocation against a local symbol
 576                   // defined in a section we are discarding.  Discard
 577                   // the reloc.  FIXME: Should we issue a warning?
 578                   strategy = Relocatable_relocs::RELOC_DISCARD;
 579                 }
 580               else if (lsym.get_st_type() != elfcpp::STT_SECTION)
 581                 strategy = scan.local_non_section_strategy(r_type, object,
 582                                                            r_sym);
 583               else
 584                 {
 585                   strategy = scan.local_section_strategy(r_type, object);
 586                   if (strategy != Relocatable_relocs::RELOC_DISCARD)
 587                     object->output_section(shndx)->set_needs_symtab_index();
 588                 }
 589
 590               if (strategy == Relocatable_relocs::RELOC_COPY)
 591                 object->set_must_have_output_symtab_entry(r_sym);
 592             }
 593         }
 594
 595       rr->set_next_reloc_strategy(strategy);
 596     }
 597 }
 598
 599 // Relocate relocs.  Called for a relocatable link, and for --emit-relocs.
 600 // This is a default definition which should work for most targets.
 601
 602 template<int size, bool big_endian, int sh_type>
 603 void
 604 relocate_relocs(
 605     const Relocate_info<size, big_endian>* relinfo,
 606     const unsigned char* prelocs,
 607     size_t reloc_count,
 608     Output_section* output_section,
 609     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 610     const Relocatable_relocs* rr,
 611     unsigned char* view,
 612     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 613     section_size_type view_size,
 614     unsigned char* reloc_view,
 615     section_size_type reloc_view_size)
 616 {
 617   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 618   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 619   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
 620     Reltype_write;
 621   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 622   const Address invalid_address = static_cast<Address>(0) - 1;
 623
 624   Sized_relobj_file<size, big_endian>* const object = relinfo->object;
 625   const unsigned int local_count = object->local_symbol_count();
 626
 627   unsigned char* pwrite = reloc_view;
 628
 629   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 630     {
 631       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
 632       if (strategy == Relocatable_relocs::RELOC_DISCARD)
 633         continue;
 634
 635       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
 636         {
 637           // Target wants to handle this relocation.
 638           Sized_target<size, big_endian>* target =
 639             parameters->sized_target<size, big_endian>();
 640           target->relocate_special_relocatable(relinfo, sh_type, prelocs,
 641                                                i, output_section,
 642                                                offset_in_output_section,
 643                                                view, view_address,
 644                                                view_size, pwrite);
 645           pwrite += reloc_size;
 646           continue;
 647         }
 648       Reltype reloc(prelocs);
 649       Reltype_write reloc_write(pwrite);
 650
 651       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 652       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 653       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 654
 655       // Get the new symbol index.
 656
 657       unsigned int new_symndx;
 658       if (r_sym < local_count)
 659         {
 660           switch (strategy)
 661             {
 662             case Relocatable_relocs::RELOC_COPY:
 663               if (r_sym == 0)
 664                 new_symndx = 0;
 665               else
 666                 {
 667                   new_symndx = object->symtab_index(r_sym);
 668                   gold_assert(new_symndx != -1U);
 669                 }
 670               break;
 671
 672             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 673             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 674             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 675             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 676             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 677             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 678             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 679               {
 680                 // We are adjusting a section symbol.  We need to find
 681                 // the symbol table index of the section symbol for
 682                 // the output section corresponding to input section
 683                 // in which this symbol is defined.
 684                 gold_assert(r_sym < local_count);
 685                 bool is_ordinary;
 686                 unsigned int shndx =
 687                   object->local_symbol_input_shndx(r_sym, &is_ordinary);
 688                 gold_assert(is_ordinary);
 689                 Output_section* os = object->output_section(shndx);
 690                 gold_assert(os != NULL);
 691                 gold_assert(os->needs_symtab_index());
 692                 new_symndx = os->symtab_index();
 693               }
 694               break;
 695
 696             default:
 697               gold_unreachable();
 698             }
 699         }
 700       else
 701         {
 702           const Symbol* gsym = object->global_symbol(r_sym);
 703           gold_assert(gsym != NULL);
 704           if (gsym->is_forwarder())
 705             gsym = relinfo->symtab->resolve_forwards(gsym);
 706
 707           gold_assert(gsym->has_symtab_index());
 708           new_symndx = gsym->symtab_index();
 709         }
 710
 711       // Get the new offset--the location in the output section where
 712       // this relocation should be applied.
 713
 714       Address offset = reloc.get_r_offset();
 715       Address new_offset;
 716       if (offset_in_output_section != invalid_address)
 717         new_offset = offset + offset_in_output_section;
 718       else
 719         {
 720           section_offset_type sot_offset =
 721               convert_types<section_offset_type, Address>(offset);
 722           section_offset_type new_sot_offset =
 723               output_section->output_offset(object, relinfo->data_shndx,
 724                                             sot_offset);
 725           gold_assert(new_sot_offset != -1);
 726           new_offset = new_sot_offset;
 727         }
 728
 729       // In an object file, r_offset is an offset within the section.
 730       // In an executable or dynamic object, generated by
 731       // --emit-relocs, r_offset is an absolute address.
 732       if (!parameters->options().relocatable())
 733         {
 734           new_offset += view_address;
 735           if (offset_in_output_section != invalid_address)
 736             new_offset -= offset_in_output_section;
 737         }
 738
 739       reloc_write.put_r_offset(new_offset);
 740       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
 741
 742       // Handle the reloc addend based on the strategy.
 743
 744       if (strategy == Relocatable_relocs::RELOC_COPY)
 745         {
 746           if (sh_type == elfcpp::SHT_RELA)
 747             Reloc_types<sh_type, size, big_endian>::
 748               copy_reloc_addend(&reloc_write,
 749                                 &reloc);
 750         }
 751       else
 752         {
 753           // The relocation uses a section symbol in the input file.
 754           // We are adjusting it to use a section symbol in the output
 755           // file.  The input section symbol refers to some address in
 756           // the input section.  We need the relocation in the output
 757           // file to refer to that same address.  This adjustment to
 758           // the addend is the same calculation we use for a simple
 759           // absolute relocation for the input section symbol.
 760
 761           const Symbol_value<size>* psymval = object->local_symbol(r_sym);
 762
 763           unsigned char* padd = view + offset;
 764           switch (strategy)
 765             {
 766             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 767               {
 768                 typename elfcpp::Elf_types<size>::Elf_Swxword addend;
 769                 addend = Reloc_types<sh_type, size, big_endian>::
 770                            get_reloc_addend(&reloc);
 771                 addend = psymval->value(object, addend);
 772                 Reloc_types<sh_type, size, big_endian>::
 773                   set_reloc_addend(&reloc_write, addend);
 774               }
 775               break;
 776
 777             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 778               break;
 779
 780             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 781               Relocate_functions<size, big_endian>::rel8(padd, object,
 782                                                          psymval);
 783               break;
 784
 785             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 786               Relocate_functions<size, big_endian>::rel16(padd, object,
 787                                                           psymval);
 788               break;
 789
 790             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 791               Relocate_functions<size, big_endian>::rel32(padd, object,
 792                                                           psymval);
 793               break;
 794
 795             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 796               Relocate_functions<size, big_endian>::rel64(padd, object,
 797                                                           psymval);
 798               break;
 799
 800             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
 801               Relocate_functions<size, big_endian>::rel32_unaligned(padd,
 802                                                                     object,
 803                                                                     psymval);
 804               break;
 805
 806             default:
 807               gold_unreachable();
 808             }
 809         }
 810
 811       pwrite += reloc_size;
 812     }
 813
 814   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
 815               == reloc_view_size);
 816 }
 817
 818 } // End namespace gold.
 819
 820 #endif // !defined(GOLD_TARGET_RELOC_H)