gold/target-reloc.h

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