gold/target-reloc.h

   1 // target-reloc.h -- target specific relocation support  -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 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 // avoidmaking 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<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 // This function implements the generic part of relocation processing.
 173 // The template parameter Relocate must be a class type which provides
 174 // a single function, relocate(), which implements the machine
 175 // specific part of a relocation.
 176
 177 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 178 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 179 // RELOCATE implements operator() to do a relocation.
 180
 181 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 182 // of relocs.  OUTPUT_SECTION is the output section.
 183 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be
 184 // mapped to output offsets.
 185
 186 // VIEW is the section data, VIEW_ADDRESS is its memory address, and
 187 // VIEW_SIZE is the size.  These refer to the input section, unless
 188 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to
 189 // the output section.
 190
 191 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support.  If it is
 192 // not NULL, it is a vector indexed by relocation index.  If that
 193 // entry is not NULL, it points to a global symbol which used as the
 194 // symbol for the relocation, ignoring the symbol index in the
 195 // relocation.
 196
 197 template<int size, bool big_endian, typename Target_type, int sh_type,
 198          typename Relocate>
 199 inline void
 200 relocate_section(
 201     const Relocate_info<size, big_endian>* relinfo,
 202     Target_type* target,
 203     const unsigned char* prelocs,
 204     size_t reloc_count,
 205     Output_section* output_section,
 206     bool needs_special_offset_handling,
 207     unsigned char* view,
 208     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 209     section_size_type view_size,
 210     const Reloc_symbol_changes* reloc_symbol_changes)
 211 {
 212   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 213   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 214   Relocate relocate;
 215
 216   Sized_relobj<size, big_endian>* object = relinfo->object;
 217   unsigned int local_count = object->local_symbol_count();
 218
 219   Comdat_behavior comdat_behavior = CB_UNDETERMINED;
 220
 221   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 222     {
 223       Reltype reloc(prelocs);
 224
 225       section_offset_type offset =
 226         convert_to_section_size_type(reloc.get_r_offset());
 227
 228       if (needs_special_offset_handling)
 229         {
 230           offset = output_section->output_offset(relinfo->object,
 231                                                  relinfo->data_shndx,
 232                                                  offset);
 233           if (offset == -1)
 234             continue;
 235         }
 236
 237       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 238       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 239       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 240
 241       const Sized_symbol<size>* sym;
 242
 243       Symbol_value<size> symval;
 244       const Symbol_value<size> *psymval;
 245       bool is_defined_in_discarded_section;
 246       unsigned int shndx;
 247       if (r_sym < local_count
 248           && (reloc_symbol_changes == NULL
 249               || (*reloc_symbol_changes)[i] == NULL))
 250         {
 251           sym = NULL;
 252           psymval = object->local_symbol(r_sym);
 253
 254           // If the local symbol belongs to a section we are discarding,
 255           // and that section is a debug section, try to find the
 256           // corresponding kept section and map this symbol to its
 257           // counterpart in the kept section.  The symbol must not
 258           // correspond to a section we are folding.
 259           bool is_ordinary;
 260           shndx = psymval->input_shndx(&is_ordinary);
 261           is_defined_in_discarded_section =
 262             (is_ordinary
 263              && shndx != elfcpp::SHN_UNDEF
 264              && !object->is_section_included(shndx)
 265              && !relinfo->symtab->is_section_folded(object, shndx));
 266         }
 267       else
 268         {
 269           const Symbol* gsym;
 270           if (reloc_symbol_changes != NULL
 271               && (*reloc_symbol_changes)[i] != NULL)
 272             gsym = (*reloc_symbol_changes)[i];
 273           else
 274             {
 275               gsym = object->global_symbol(r_sym);
 276               gold_assert(gsym != NULL);
 277               if (gsym->is_forwarder())
 278                 gsym = relinfo->symtab->resolve_forwards(gsym);
 279             }
 280
 281           sym = static_cast<const Sized_symbol<size>*>(gsym);
 282           if (sym->has_symtab_index() && sym->symtab_index() != -1U)
 283             symval.set_output_symtab_index(sym->symtab_index());
 284           else
 285             symval.set_no_output_symtab_entry();
 286           symval.set_output_value(sym->value());
 287           psymval = &symval;
 288
 289           is_defined_in_discarded_section =
 290             (gsym->is_defined_in_discarded_section()
 291              && gsym->is_undefined());
 292           shndx = 0;
 293         }
 294
 295       Symbol_value<size> symval2;
 296       if (is_defined_in_discarded_section)
 297         {
 298           if (comdat_behavior == CB_UNDETERMINED)
 299             {
 300               std::string name = object->section_name(relinfo->data_shndx);
 301               comdat_behavior = get_comdat_behavior(name.c_str());
 302             }
 303           if (comdat_behavior == CB_PRETEND)
 304             {
 305               // FIXME: This case does not work for global symbols.
 306               // We have no place to store the original section index.
 307               // Fortunately this does not matter for comdat sections,
 308               // only for sections explicitly discarded by a linker
 309               // script.
 310               bool found;
 311               typename elfcpp::Elf_types<size>::Elf_Addr value =
 312                 object->map_to_kept_section(shndx, &found);
 313               if (found)
 314                 symval2.set_output_value(value + psymval->input_value());
 315               else
 316                 symval2.set_output_value(0);
 317             }
 318           else
 319             {
 320               if (comdat_behavior == CB_WARNING)
 321                 gold_warning_at_location(relinfo, i, offset,
 322                                          _("relocation refers to discarded "
 323                                            "section"));
 324               symval2.set_output_value(0);
 325             }
 326           symval2.set_no_output_symtab_entry();
 327           psymval = &symval2;
 328         }
 329
 330       if (!relocate.relocate(relinfo, target, output_section, i, reloc,
 331                              r_type, sym, psymval, view + offset,
 332                              view_address + offset, view_size))
 333         continue;
 334
 335       if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
 336         {
 337           gold_error_at_location(relinfo, i, offset,
 338                                  _("reloc has bad offset %zu"),
 339                                  static_cast<size_t>(offset));
 340           continue;
 341         }
 342
 343       if (sym != NULL
 344           && sym->is_undefined()
 345           && sym->binding() != elfcpp::STB_WEAK
 346           && !is_defined_in_discarded_section
 347           && !target->is_defined_by_abi(sym)
 348           && (!parameters->options().shared()       // -shared
 349               || parameters->options().defs()))     // -z defs
 350         gold_undefined_symbol_at_location(sym, relinfo, i, offset);
 351       else if (sym != NULL
 352                && sym->visibility() != elfcpp::STV_DEFAULT
 353                && (sym->is_undefined() || sym->is_from_dynobj()))
 354         visibility_error(sym);
 355
 356       if (sym != NULL && sym->has_warning())
 357         relinfo->symtab->issue_warning(sym, relinfo, i, offset);
 358     }
 359 }
 360
 361 // This class may be used as a typical class for the
 362 // Scan_relocatable_reloc parameter to scan_relocatable_relocs.  The
 363 // template parameter Classify_reloc must be a class type which
 364 // provides a function get_size_for_reloc which returns the number of
 365 // bytes to which a reloc applies.  This class is intended to capture
 366 // the most typical target behaviour, while still permitting targets
 367 // to define their own independent class for Scan_relocatable_reloc.
 368
 369 template<int sh_type, typename Classify_reloc>
 370 class Default_scan_relocatable_relocs
 371 {
 372  public:
 373   // Return the strategy to use for a local symbol which is not a
 374   // section symbol, given the relocation type.
 375   inline Relocatable_relocs::Reloc_strategy
 376   local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym)
 377   {
 378     // We assume that relocation type 0 is NONE.  Targets which are
 379     // different must override.
 380     if (r_type == 0 && r_sym == 0)
 381       return Relocatable_relocs::RELOC_DISCARD;
 382     return Relocatable_relocs::RELOC_COPY;
 383   }
 384
 385   // Return the strategy to use for a local symbol which is a section
 386   // symbol, given the relocation type.
 387   inline Relocatable_relocs::Reloc_strategy
 388   local_section_strategy(unsigned int r_type, Relobj* object)
 389   {
 390     if (sh_type == elfcpp::SHT_RELA)
 391       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
 392     else
 393       {
 394         Classify_reloc classify;
 395         switch (classify.get_size_for_reloc(r_type, object))
 396           {
 397           case 0:
 398             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
 399           case 1:
 400             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
 401           case 2:
 402             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
 403           case 4:
 404             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
 405           case 8:
 406             return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
 407           default:
 408             gold_unreachable();
 409           }
 410       }
 411   }
 412
 413   // Return the strategy to use for a global symbol, given the
 414   // relocation type, the object, and the symbol index.
 415   inline Relocatable_relocs::Reloc_strategy
 416   global_strategy(unsigned int, Relobj*, unsigned int)
 417   { return Relocatable_relocs::RELOC_COPY; }
 418 };
 419
 420 // Scan relocs during a relocatable link.  This is a default
 421 // definition which should work for most targets.
 422 // Scan_relocatable_reloc must name a class type which provides three
 423 // functions which return a Relocatable_relocs::Reloc_strategy code:
 424 // global_strategy, local_non_section_strategy, and
 425 // local_section_strategy.  Most targets should be able to use
 426 // Default_scan_relocatable_relocs as this class.
 427
 428 template<int size, bool big_endian, int sh_type,
 429          typename Scan_relocatable_reloc>
 430 void
 431 scan_relocatable_relocs(
 432     Symbol_table*,
 433     Layout*,
 434     Sized_relobj<size, big_endian>* object,
 435     unsigned int data_shndx,
 436     const unsigned char* prelocs,
 437     size_t reloc_count,
 438     Output_section* output_section,
 439     bool needs_special_offset_handling,
 440     size_t local_symbol_count,
 441     const unsigned char* plocal_syms,
 442     Relocatable_relocs* rr)
 443 {
 444   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 445   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 446   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 447   Scan_relocatable_reloc scan;
 448
 449   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 450     {
 451       Reltype reloc(prelocs);
 452
 453       Relocatable_relocs::Reloc_strategy strategy;
 454
 455       if (needs_special_offset_handling
 456           && !output_section->is_input_address_mapped(object, data_shndx,
 457                                                       reloc.get_r_offset()))
 458         strategy = Relocatable_relocs::RELOC_DISCARD;
 459       else
 460         {
 461           typename elfcpp::Elf_types<size>::Elf_WXword r_info =
 462             reloc.get_r_info();
 463           const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 464           const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 465
 466           if (r_sym >= local_symbol_count)
 467             strategy = scan.global_strategy(r_type, object, r_sym);
 468           else
 469             {
 470               gold_assert(plocal_syms != NULL);
 471               typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
 472                                                           + r_sym * sym_size);
 473               unsigned int shndx = lsym.get_st_shndx();
 474               bool is_ordinary;
 475               shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
 476               if (is_ordinary
 477                   && shndx != elfcpp::SHN_UNDEF
 478                   && !object->is_section_included(shndx))
 479                 {
 480                   // RELOC is a relocation against a local symbol
 481                   // defined in a section we are discarding.  Discard
 482                   // the reloc.  FIXME: Should we issue a warning?
 483                   strategy = Relocatable_relocs::RELOC_DISCARD;
 484                 }
 485               else if (lsym.get_st_type() != elfcpp::STT_SECTION)
 486                 strategy = scan.local_non_section_strategy(r_type, object,
 487                                                            r_sym);
 488               else
 489                 {
 490                   strategy = scan.local_section_strategy(r_type, object);
 491                   if (strategy != Relocatable_relocs::RELOC_DISCARD)
 492                     object->output_section(shndx)->set_needs_symtab_index();
 493                 }
 494
 495               if (strategy == Relocatable_relocs::RELOC_COPY)
 496                 object->set_must_have_output_symtab_entry(r_sym);
 497             }
 498         }
 499
 500       rr->set_next_reloc_strategy(strategy);
 501     }
 502 }
 503
 504 // Relocate relocs during a relocatable link.  This is a default
 505 // definition which should work for most targets.
 506
 507 template<int size, bool big_endian, int sh_type>
 508 void
 509 relocate_for_relocatable(
 510     const Relocate_info<size, big_endian>* relinfo,
 511     const unsigned char* prelocs,
 512     size_t reloc_count,
 513     Output_section* output_section,
 514     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
 515     const Relocatable_relocs* rr,
 516     unsigned char* view,
 517     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 518     section_size_type view_size,
 519     unsigned char* reloc_view,
 520     section_size_type reloc_view_size)
 521 {
 522   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 523   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 524   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
 525     Reltype_write;
 526   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 527   const Address invalid_address = static_cast<Address>(0) - 1;
 528
 529   Sized_relobj<size, big_endian>* const object = relinfo->object;
 530   const unsigned int local_count = object->local_symbol_count();
 531
 532   unsigned char* pwrite = reloc_view;
 533
 534   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 535     {
 536       Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
 537       if (strategy == Relocatable_relocs::RELOC_DISCARD)
 538         continue;
 539
 540       if (strategy == Relocatable_relocs::RELOC_SPECIAL)
 541         {
 542           // Target wants to handle this relocation.
 543           Sized_target<size, big_endian>* target =
 544             parameters->sized_target<size, big_endian>();
 545           target->relocate_special_relocatable(relinfo, sh_type, prelocs,
 546                                                i, output_section,
 547                                                offset_in_output_section,
 548                                                view, view_address,
 549                                                view_size, pwrite);
 550           pwrite += reloc_size;
 551           continue;
 552         }
 553       Reltype reloc(prelocs);
 554       Reltype_write reloc_write(pwrite);
 555
 556       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 557       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 558       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 559
 560       // Get the new symbol index.
 561
 562       unsigned int new_symndx;
 563       if (r_sym < local_count)
 564         {
 565           switch (strategy)
 566             {
 567             case Relocatable_relocs::RELOC_COPY:
 568               if (r_sym == 0)
 569                 new_symndx = 0;
 570               else
 571                 {
 572                   new_symndx = object->symtab_index(r_sym);
 573                   gold_assert(new_symndx != -1U);
 574                 }
 575               break;
 576
 577             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 578             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 579             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 580             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 581             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 582             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 583               {
 584                 // We are adjusting a section symbol.  We need to find
 585                 // the symbol table index of the section symbol for
 586                 // the output section corresponding to input section
 587                 // in which this symbol is defined.
 588                 gold_assert(r_sym < local_count);
 589                 bool is_ordinary;
 590                 unsigned int shndx =
 591                   object->local_symbol_input_shndx(r_sym, &is_ordinary);
 592                 gold_assert(is_ordinary);
 593                 Output_section* os = object->output_section(shndx);
 594                 gold_assert(os != NULL);
 595                 gold_assert(os->needs_symtab_index());
 596                 new_symndx = os->symtab_index();
 597               }
 598               break;
 599
 600             default:
 601               gold_unreachable();
 602             }
 603         }
 604       else
 605         {
 606           const Symbol* gsym = object->global_symbol(r_sym);
 607           gold_assert(gsym != NULL);
 608           if (gsym->is_forwarder())
 609             gsym = relinfo->symtab->resolve_forwards(gsym);
 610
 611           gold_assert(gsym->has_symtab_index());
 612           new_symndx = gsym->symtab_index();
 613         }
 614
 615       // Get the new offset--the location in the output section where
 616       // this relocation should be applied.
 617
 618       Address offset = reloc.get_r_offset();
 619       Address new_offset;
 620       if (offset_in_output_section != invalid_address)
 621         new_offset = offset + offset_in_output_section;
 622       else
 623         {
 624           section_offset_type sot_offset =
 625               convert_types<section_offset_type, Address>(offset);
 626           section_offset_type new_sot_offset =
 627               output_section->output_offset(object, relinfo->data_shndx,
 628                                             sot_offset);
 629           gold_assert(new_sot_offset != -1);
 630           new_offset = new_sot_offset;
 631         }
 632
 633       // In an object file, r_offset is an offset within the section.
 634       // In an executable or dynamic object, generated by
 635       // --emit-relocs, r_offset is an absolute address.
 636       if (!parameters->options().relocatable())
 637         {
 638           new_offset += view_address;
 639           if (offset_in_output_section != invalid_address)
 640             new_offset -= offset_in_output_section;
 641         }
 642
 643       reloc_write.put_r_offset(new_offset);
 644       reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
 645
 646       // Handle the reloc addend based on the strategy.
 647
 648       if (strategy == Relocatable_relocs::RELOC_COPY)
 649         {
 650           if (sh_type == elfcpp::SHT_RELA)
 651             Reloc_types<sh_type, size, big_endian>::
 652               copy_reloc_addend(&reloc_write,
 653                                 &reloc);
 654         }
 655       else
 656         {
 657           // The relocation uses a section symbol in the input file.
 658           // We are adjusting it to use a section symbol in the output
 659           // file.  The input section symbol refers to some address in
 660           // the input section.  We need the relocation in the output
 661           // file to refer to that same address.  This adjustment to
 662           // the addend is the same calculation we use for a simple
 663           // absolute relocation for the input section symbol.
 664
 665           const Symbol_value<size>* psymval = object->local_symbol(r_sym);
 666
 667           unsigned char* padd = view + offset;
 668           switch (strategy)
 669             {
 670             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
 671               {
 672                 typename elfcpp::Elf_types<size>::Elf_Swxword addend;
 673                 addend = Reloc_types<sh_type, size, big_endian>::
 674                            get_reloc_addend(&reloc);
 675                 addend = psymval->value(object, addend);
 676                 Reloc_types<sh_type, size, big_endian>::
 677                   set_reloc_addend(&reloc_write, addend);
 678               }
 679               break;
 680
 681             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0:
 682               break;
 683
 684             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
 685               Relocate_functions<size, big_endian>::rel8(padd, object,
 686                                                          psymval);
 687               break;
 688
 689             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
 690               Relocate_functions<size, big_endian>::rel16(padd, object,
 691                                                           psymval);
 692               break;
 693
 694             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
 695               Relocate_functions<size, big_endian>::rel32(padd, object,
 696                                                           psymval);
 697               break;
 698
 699             case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
 700               Relocate_functions<size, big_endian>::rel64(padd, object,
 701                                                           psymval);
 702               break;
 703
 704             default:
 705               gold_unreachable();
 706             }
 707         }
 708
 709       pwrite += reloc_size;
 710     }
 711
 712   gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
 713               == reloc_view_size);
 714 }
 715
 716 } // End namespace gold.
 717
 718 #endif // !defined(GOLD_TARGET_RELOC_H)