gold/merge.cc

   1 // merge.cc -- handle section merging for gold
   2
   3 // Copyright (C) 2006-2015 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 #include "gold.h"
  24
  25 #include <cstdlib>
  26 #include <algorithm>
  27
  28 #include "merge.h"
  29 #include "compressed_output.h"
  30
  31 namespace gold
  32 {
  33
  34 // Class Object_merge_map.
  35
  36 // Destructor.
  37
  38 Object_merge_map::~Object_merge_map()
  39 {
  40   for (Section_merge_maps::iterator p = this->section_merge_maps_.begin();
  41        p != this->section_merge_maps_.end();
  42        ++p)
  43     delete p->second;
  44 }
  45
  46 // Get the Input_merge_map to use for an input section, or NULL.
  47
  48 Object_merge_map::Input_merge_map*
  49 Object_merge_map::get_input_merge_map(unsigned int shndx)
  50 {
  51   gold_assert(shndx != -1U);
  52   if (shndx == this->first_shnum_)
  53     return &this->first_map_;
  54   if (shndx == this->second_shnum_)
  55     return &this->second_map_;
  56   Section_merge_maps::const_iterator p = this->section_merge_maps_.find(shndx);
  57   if (p != this->section_merge_maps_.end())
  58     return p->second;
  59   return NULL;
  60 }
  61
  62 // Get or create the Input_merge_map to use for an input section.
  63
  64 Object_merge_map::Input_merge_map*
  65 Object_merge_map::get_or_make_input_merge_map(const Merge_map* merge_map,
  66                                               unsigned int shndx)
  67 {
  68   Input_merge_map* map = this->get_input_merge_map(shndx);
  69   if (map != NULL)
  70     {
  71       // For a given input section in a given object, every mapping
  72       // must be done with the same Merge_map.
  73       gold_assert(map->merge_map == merge_map);
  74       return map;
  75     }
  76
  77   // We need to create a new entry.
  78   if (this->first_shnum_ == -1U)
  79     {
  80       this->first_shnum_ = shndx;
  81       this->first_map_.merge_map = merge_map;
  82       return &this->first_map_;
  83     }
  84   if (this->second_shnum_ == -1U)
  85     {
  86       this->second_shnum_ = shndx;
  87       this->second_map_.merge_map = merge_map;
  88       return &this->second_map_;
  89     }
  90
  91   Input_merge_map* new_map = new Input_merge_map;
  92   new_map->merge_map = merge_map;
  93   this->section_merge_maps_[shndx] = new_map;
  94   return new_map;
  95 }
  96
  97 // Add a mapping.
  98
  99 void
 100 Object_merge_map::add_mapping(const Merge_map* merge_map, unsigned int shndx,
 101                               section_offset_type input_offset,
 102                               section_size_type length,
 103                               section_offset_type output_offset)
 104 {
 105   Input_merge_map* map = this->get_or_make_input_merge_map(merge_map, shndx);
 106
 107   // Try to merge the new entry in the last one we saw.
 108   if (!map->entries.empty())
 109     {
 110       Input_merge_entry& entry(map->entries.back());
 111
 112       // Use section_size_type to avoid signed/unsigned warnings.
 113       section_size_type input_offset_u = input_offset;
 114       section_size_type output_offset_u = output_offset;
 115
 116       // If this entry is not in order, we need to sort the vector
 117       // before looking anything up.
 118       if (input_offset_u < entry.input_offset + entry.length)
 119         {
 120           gold_assert(input_offset < entry.input_offset);
 121           gold_assert(input_offset_u + length
 122                       <= static_cast<section_size_type>(entry.input_offset));
 123           map->sorted = false;
 124         }
 125       else if (entry.input_offset + entry.length == input_offset_u
 126                && (output_offset == -1
 127                    ? entry.output_offset == -1
 128                    : entry.output_offset + entry.length == output_offset_u))
 129         {
 130           entry.length += length;
 131           return;
 132         }
 133     }
 134
 135   Input_merge_entry entry;
 136   entry.input_offset = input_offset;
 137   entry.length = length;
 138   entry.output_offset = output_offset;
 139   map->entries.push_back(entry);
 140 }
 141
 142 // Get the output offset for an input address.
 143
 144 bool
 145 Object_merge_map::get_output_offset(const Merge_map* merge_map,
 146                                     unsigned int shndx,
 147                                     section_offset_type input_offset,
 148                                     section_offset_type* output_offset)
 149 {
 150   Input_merge_map* map = this->get_input_merge_map(shndx);
 151   if (map == NULL
 152       || (merge_map != NULL && map->merge_map != merge_map))
 153     return false;
 154
 155   if (!map->sorted)
 156     {
 157       std::sort(map->entries.begin(), map->entries.end(),
 158                 Input_merge_compare());
 159       map->sorted = true;
 160     }
 161
 162   Input_merge_entry entry;
 163   entry.input_offset = input_offset;
 164   std::vector<Input_merge_entry>::const_iterator p =
 165     std::upper_bound(map->entries.begin(), map->entries.end(),
 166                      entry, Input_merge_compare());
 167   if (p == map->entries.begin())
 168     return false;
 169   --p;
 170   gold_assert(p->input_offset <= input_offset);
 171
 172   if (input_offset - p->input_offset
 173       >= static_cast<section_offset_type>(p->length))
 174     return false;
 175
 176   *output_offset = p->output_offset;
 177   if (*output_offset != -1)
 178     *output_offset += (input_offset - p->input_offset);
 179   return true;
 180 }
 181
 182 // Return whether this is the merge map for section SHNDX.
 183
 184 inline bool
 185 Object_merge_map::is_merge_section_for(const Merge_map* merge_map,
 186                                        unsigned int shndx)
 187 {
 188   Input_merge_map* map = this->get_input_merge_map(shndx);
 189   return map != NULL && map->merge_map == merge_map;
 190 }
 191
 192 // Initialize a mapping from input offsets to output addresses.
 193
 194 template<int size>
 195 void
 196 Object_merge_map::initialize_input_to_output_map(
 197     unsigned int shndx,
 198     typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
 199     Unordered_map<section_offset_type,
 200                   typename elfcpp::Elf_types<size>::Elf_Addr>* initialize_map)
 201 {
 202   Input_merge_map* map = this->get_input_merge_map(shndx);
 203   gold_assert(map != NULL);
 204
 205   gold_assert(initialize_map->empty());
 206   // We know how many entries we are going to add.
 207   // reserve_unordered_map takes an expected count of buckets, not a
 208   // count of elements, so double it to try to reduce collisions.
 209   reserve_unordered_map(initialize_map, map->entries.size() * 2);
 210
 211   for (Input_merge_map::Entries::const_iterator p = map->entries.begin();
 212        p != map->entries.end();
 213        ++p)
 214     {
 215       section_offset_type output_offset = p->output_offset;
 216       if (output_offset != -1)
 217         output_offset += starting_address;
 218       else
 219         {
 220           // If we see a relocation against an address we have chosen
 221           // to discard, we relocate to zero.  FIXME: We could also
 222           // issue a warning in this case; that would require
 223           // reporting this somehow and checking it in the routines in
 224           // reloc.h.
 225           output_offset = 0;
 226         }
 227       initialize_map->insert(std::make_pair(p->input_offset, output_offset));
 228     }
 229 }
 230
 231 // Class Merge_map.
 232
 233 // Add a mapping for the bytes from OFFSET to OFFSET + LENGTH in input
 234 // section SHNDX in object OBJECT to an OUTPUT_OFFSET in merged data
 235 // in an output section.
 236
 237 void
 238 Merge_map::add_mapping(Relobj* object, unsigned int shndx,
 239                        section_offset_type offset, section_size_type length,
 240                        section_offset_type output_offset)
 241 {
 242   gold_assert(object != NULL);
 243   Object_merge_map* object_merge_map = object->merge_map();
 244   if (object_merge_map == NULL)
 245     {
 246       object_merge_map = new Object_merge_map();
 247       object->set_merge_map(object_merge_map);
 248     }
 249
 250   object_merge_map->add_mapping(this, shndx, offset, length, output_offset);
 251 }
 252
 253 // Return the output offset for an input address.  The input address
 254 // is at offset OFFSET in section SHNDX in OBJECT.  This sets
 255 // *OUTPUT_OFFSET to the offset in the merged data in the output
 256 // section.  This returns true if the mapping is known, false
 257 // otherwise.
 258
 259 bool
 260 Merge_map::get_output_offset(const Relobj* object, unsigned int shndx,
 261                              section_offset_type offset,
 262                              section_offset_type* output_offset) const
 263 {
 264   Object_merge_map* object_merge_map = object->merge_map();
 265   if (object_merge_map == NULL)
 266     return false;
 267   return object_merge_map->get_output_offset(this, shndx, offset,
 268                                              output_offset);
 269 }
 270
 271 // Return whether this is the merge section for SHNDX in OBJECT.
 272
 273 bool
 274 Merge_map::is_merge_section_for(const Relobj* object, unsigned int shndx) const
 275 {
 276   Object_merge_map* object_merge_map = object->merge_map();
 277   if (object_merge_map == NULL)
 278     return false;
 279   return object_merge_map->is_merge_section_for(this, shndx);
 280 }
 281
 282 // Class Output_merge_base.
 283
 284 // Return the output offset for an input offset.  The input address is
 285 // at offset OFFSET in section SHNDX in OBJECT.  If we know the
 286 // offset, set *POUTPUT and return true.  Otherwise return false.
 287
 288 bool
 289 Output_merge_base::do_output_offset(const Relobj* object,
 290                                     unsigned int shndx,
 291                                     section_offset_type offset,
 292                                     section_offset_type* poutput) const
 293 {
 294   return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
 295 }
 296
 297 // Return whether this is the merge section for SHNDX in OBJECT.
 298
 299 bool
 300 Output_merge_base::do_is_merge_section_for(const Relobj* object,
 301                                            unsigned int shndx) const
 302 {
 303   return this->merge_map_.is_merge_section_for(object, shndx);
 304 }
 305
 306 // Record a merged input section for script processing.
 307
 308 void
 309 Output_merge_base::record_input_section(Relobj* relobj, unsigned int shndx)
 310 {
 311   gold_assert(this->keeps_input_sections_ && relobj != NULL);
 312   // If this is the first input section, record it.  We need do this because
 313   // this->input_sections_ is unordered.
 314   if (this->first_relobj_ == NULL)
 315     {
 316       this->first_relobj_ = relobj;
 317       this->first_shndx_ = shndx;
 318     }
 319
 320   std::pair<Input_sections::iterator, bool> result =
 321     this->input_sections_.insert(Section_id(relobj, shndx));
 322   // We should insert a merge section once only.
 323   gold_assert(result.second);
 324 }
 325
 326 // Class Output_merge_data.
 327
 328 // Compute the hash code for a fixed-size constant.
 329
 330 size_t
 331 Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const
 332 {
 333   const unsigned char* p = this->pomd_->constant(k);
 334   section_size_type entsize =
 335     convert_to_section_size_type(this->pomd_->entsize());
 336
 337   // Fowler/Noll/Vo (FNV) hash (type FNV-1a).
 338   if (sizeof(size_t) == 8)
 339     {
 340       size_t result = static_cast<size_t>(14695981039346656037ULL);
 341       for (section_size_type i = 0; i < entsize; ++i)
 342         {
 343           result &= (size_t) *p++;
 344           result *= 1099511628211ULL;
 345         }
 346       return result;
 347     }
 348   else
 349     {
 350       size_t result = 2166136261UL;
 351       for (section_size_type i = 0; i < entsize; ++i)
 352         {
 353           result ^= (size_t) *p++;
 354           result *= 16777619UL;
 355         }
 356       return result;
 357     }
 358 }
 359
 360 // Return whether one hash table key equals another.
 361
 362 bool
 363 Output_merge_data::Merge_data_eq::operator()(Merge_data_key k1,
 364                                              Merge_data_key k2) const
 365 {
 366   const unsigned char* p1 = this->pomd_->constant(k1);
 367   const unsigned char* p2 = this->pomd_->constant(k2);
 368   return memcmp(p1, p2, this->pomd_->entsize()) == 0;
 369 }
 370
 371 // Add a constant to the end of the section contents.
 372
 373 void
 374 Output_merge_data::add_constant(const unsigned char* p)
 375 {
 376   section_size_type entsize = convert_to_section_size_type(this->entsize());
 377   section_size_type addralign =
 378     convert_to_section_size_type(this->addralign());
 379   section_size_type addsize = std::max(entsize, addralign);
 380   if (this->len_ + addsize > this->alc_)
 381     {
 382       if (this->alc_ == 0)
 383         this->alc_ = 128 * addsize;
 384       else
 385         this->alc_ *= 2;
 386       this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->alc_));
 387       if (this->p_ == NULL)
 388         gold_nomem();
 389     }
 390
 391   memcpy(this->p_ + this->len_, p, entsize);
 392   if (addsize > entsize)
 393     memset(this->p_ + this->len_ + entsize, 0, addsize - entsize);
 394   this->len_ += addsize;
 395 }
 396
 397 // Add the input section SHNDX in OBJECT to a merged output section
 398 // which holds fixed length constants.  Return whether we were able to
 399 // handle the section; if not, it will be linked as usual without
 400 // constant merging.
 401
 402 bool
 403 Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
 404 {
 405   section_size_type len;
 406   bool is_new;
 407   const unsigned char* p = object->decompressed_section_contents(shndx, &len,
 408                                                                  &is_new);
 409
 410   section_size_type entsize = convert_to_section_size_type(this->entsize());
 411
 412   if (len % entsize != 0)
 413     {
 414       if (is_new)
 415         delete[] p;
 416       return false;
 417     }
 418
 419   this->input_count_ += len / entsize;
 420
 421   for (section_size_type i = 0; i < len; i += entsize, p += entsize)
 422     {
 423       // Add the constant to the section contents.  If we find that it
 424       // is already in the hash table, we will remove it again.
 425       Merge_data_key k = this->len_;
 426       this->add_constant(p);
 427
 428       std::pair<Merge_data_hashtable::iterator, bool> ins =
 429         this->hashtable_.insert(k);
 430
 431       if (!ins.second)
 432         {
 433           // Key was already present.  Remove the copy we just added.
 434           this->len_ -= entsize;
 435           k = *ins.first;
 436         }
 437
 438       // Record the offset of this constant in the output section.
 439       this->add_mapping(object, shndx, i, entsize, k);
 440     }
 441
 442   // For script processing, we keep the input sections.
 443   if (this->keeps_input_sections())
 444     record_input_section(object, shndx);
 445
 446   if (is_new)
 447     delete[] p;
 448
 449   return true;
 450 }
 451
 452 // Set the final data size in a merged output section with fixed size
 453 // constants.
 454
 455 void
 456 Output_merge_data::set_final_data_size()
 457 {
 458   // Release the memory we don't need.
 459   this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->len_));
 460   // An Output_merge_data object may be empty and realloc is allowed
 461   // to return a NULL pointer in this case.  An Output_merge_data is empty
 462   // if all its input sections have sizes that are not multiples of entsize.
 463   gold_assert(this->p_ != NULL || this->len_ == 0);
 464   this->set_data_size(this->len_);
 465 }
 466
 467 // Write the data of a merged output section with fixed size constants
 468 // to the file.
 469
 470 void
 471 Output_merge_data::do_write(Output_file* of)
 472 {
 473   of->write(this->offset(), this->p_, this->len_);
 474 }
 475
 476 // Write the data to a buffer.
 477
 478 void
 479 Output_merge_data::do_write_to_buffer(unsigned char* buffer)
 480 {
 481   memcpy(buffer, this->p_, this->len_);
 482 }
 483
 484 // Print merge stats to stderr.
 485
 486 void
 487 Output_merge_data::do_print_merge_stats(const char* section_name)
 488 {
 489   fprintf(stderr,
 490           _("%s: %s merged constants size: %lu; input: %zu; output: %zu\n"),
 491           program_name, section_name,
 492           static_cast<unsigned long>(this->entsize()),
 493           this->input_count_, this->hashtable_.size());
 494 }
 495
 496 // Class Output_merge_string.
 497
 498 // Add an input section to a merged string section.
 499
 500 template<typename Char_type>
 501 bool
 502 Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
 503                                                      unsigned int shndx)
 504 {
 505   section_size_type sec_len;
 506   bool is_new;
 507   const unsigned char* pdata = object->decompressed_section_contents(shndx,
 508                                                                      &sec_len,
 509                                                                      &is_new);
 510
 511   const Char_type* p = reinterpret_cast<const Char_type*>(pdata);
 512   const Char_type* pend = p + sec_len / sizeof(Char_type);
 513   const Char_type* pend0 = pend;
 514
 515   if (sec_len % sizeof(Char_type) != 0)
 516     {
 517       object->error(_("mergeable string section length not multiple of "
 518                       "character size"));
 519       if (is_new)
 520         delete[] pdata;
 521       return false;
 522     }
 523
 524   if (pend[-1] != 0)
 525     {
 526       gold_warning(_("%s: last entry in mergeable string section '%s' "
 527                      "not null terminated"),
 528                    object->name().c_str(),
 529                    object->section_name(shndx).c_str());
 530       // Find the end of the last NULL-terminated string in the buffer.
 531       while (pend0 > p && pend0[-1] != 0)
 532         --pend0;
 533     }
 534
 535   Merged_strings_list* merged_strings_list =
 536       new Merged_strings_list(object, shndx);
 537   this->merged_strings_lists_.push_back(merged_strings_list);
 538   Merged_strings& merged_strings = merged_strings_list->merged_strings;
 539
 540   // Count the number of non-null strings in the section and size the list.
 541   size_t count = 0;
 542   const Char_type* pt = p;
 543   while (pt < pend0)
 544     {
 545       size_t len = string_length(pt);
 546       if (len != 0)
 547         ++count;
 548       pt += len + 1;
 549     }
 550   if (pend0 < pend)
 551     ++count;
 552   merged_strings.reserve(count + 1);
 553
 554   // The index I is in bytes, not characters.
 555   section_size_type i = 0;
 556
 557   // We assume here that the beginning of the section is correctly
 558   // aligned, so each string within the section must retain the same
 559   // modulo.
 560   uintptr_t init_align_modulo = (reinterpret_cast<uintptr_t>(pdata)
 561                                  & (this->addralign() - 1));
 562   bool has_misaligned_strings = false;
 563
 564   while (p < pend)
 565     {
 566       size_t len = p < pend0 ? string_length(p) : pend - p;
 567
 568       // Within merge input section each string must be aligned.
 569       if (len != 0
 570           && ((reinterpret_cast<uintptr_t>(p) & (this->addralign() - 1))
 571               != init_align_modulo))
 572           has_misaligned_strings = true;
 573
 574       Stringpool::Key key;
 575       this->stringpool_.add_with_length(p, len, true, &key);
 576
 577       merged_strings.push_back(Merged_string(i, key));
 578       p += len + 1;
 579       i += (len + 1) * sizeof(Char_type);
 580     }
 581
 582   // Record the last offset in the input section so that we can
 583   // compute the length of the last string.
 584   merged_strings.push_back(Merged_string(i, 0));
 585
 586   this->input_count_ += count;
 587   this->input_size_ += i;
 588
 589   if (has_misaligned_strings)
 590     gold_warning(_("%s: section %s contains incorrectly aligned strings;"
 591                    " the alignment of those strings won't be preserved"),
 592                  object->name().c_str(),
 593                  object->section_name(shndx).c_str());
 594
 595   // For script processing, we keep the input sections.
 596   if (this->keeps_input_sections())
 597     record_input_section(object, shndx);
 598
 599   if (is_new)
 600     delete[] pdata;
 601
 602   return true;
 603 }
 604
 605 // Finalize the mappings from the input sections to the output
 606 // section, and return the final data size.
 607
 608 template<typename Char_type>
 609 section_size_type
 610 Output_merge_string<Char_type>::finalize_merged_data()
 611 {
 612   this->stringpool_.set_string_offsets();
 613
 614   for (typename Merged_strings_lists::const_iterator l =
 615          this->merged_strings_lists_.begin();
 616        l != this->merged_strings_lists_.end();
 617        ++l)
 618     {
 619       section_offset_type last_input_offset = 0;
 620       section_offset_type last_output_offset = 0;
 621       for (typename Merged_strings::const_iterator p =
 622              (*l)->merged_strings.begin();
 623            p != (*l)->merged_strings.end();
 624            ++p)
 625         {
 626           section_size_type length = p->offset - last_input_offset;
 627           if (length > 0)
 628             this->add_mapping((*l)->object, (*l)->shndx, last_input_offset,
 629                               length, last_output_offset);
 630           last_input_offset = p->offset;
 631           if (p->stringpool_key != 0)
 632             last_output_offset =
 633                 this->stringpool_.get_offset_from_key(p->stringpool_key);
 634         }
 635       delete *l;
 636     }
 637
 638   // Save some memory.  This also ensures that this function will work
 639   // if called twice, as may happen if Layout::set_segment_offsets
 640   // finds a better alignment.
 641   this->merged_strings_lists_.clear();
 642
 643   return this->stringpool_.get_strtab_size();
 644 }
 645
 646 template<typename Char_type>
 647 void
 648 Output_merge_string<Char_type>::set_final_data_size()
 649 {
 650   const off_t final_data_size = this->finalize_merged_data();
 651   this->set_data_size(final_data_size);
 652 }
 653
 654 // Write out a merged string section.
 655
 656 template<typename Char_type>
 657 void
 658 Output_merge_string<Char_type>::do_write(Output_file* of)
 659 {
 660   this->stringpool_.write(of, this->offset());
 661 }
 662
 663 // Write a merged string section to a buffer.
 664
 665 template<typename Char_type>
 666 void
 667 Output_merge_string<Char_type>::do_write_to_buffer(unsigned char* buffer)
 668 {
 669   this->stringpool_.write_to_buffer(buffer, this->data_size());
 670 }
 671
 672 // Return the name of the types of string to use with
 673 // do_print_merge_stats.
 674
 675 template<typename Char_type>
 676 const char*
 677 Output_merge_string<Char_type>::string_name()
 678 {
 679   gold_unreachable();
 680   return NULL;
 681 }
 682
 683 template<>
 684 const char*
 685 Output_merge_string<char>::string_name()
 686 {
 687   return "strings";
 688 }
 689
 690 template<>
 691 const char*
 692 Output_merge_string<uint16_t>::string_name()
 693 {
 694   return "16-bit strings";
 695 }
 696
 697 template<>
 698 const char*
 699 Output_merge_string<uint32_t>::string_name()
 700 {
 701   return "32-bit strings";
 702 }
 703
 704 // Print merge stats to stderr.
 705
 706 template<typename Char_type>
 707 void
 708 Output_merge_string<Char_type>::do_print_merge_stats(const char* section_name)
 709 {
 710   char buf[200];
 711   snprintf(buf, sizeof buf, "%s merged %s", section_name, this->string_name());
 712   fprintf(stderr, _("%s: %s input bytes: %zu\n"),
 713           program_name, buf, this->input_size_);
 714   fprintf(stderr, _("%s: %s input strings: %zu\n"),
 715           program_name, buf, this->input_count_);
 716   this->stringpool_.print_stats(buf);
 717 }
 718
 719 // Instantiate the templates we need.
 720
 721 template
 722 class Output_merge_string<char>;
 723
 724 template
 725 class Output_merge_string<uint16_t>;
 726
 727 template
 728 class Output_merge_string<uint32_t>;
 729
 730 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
 731 template
 732 void
 733 Object_merge_map::initialize_input_to_output_map<32>(
 734     unsigned int shndx,
 735     elfcpp::Elf_types<32>::Elf_Addr starting_address,
 736     Unordered_map<section_offset_type, elfcpp::Elf_types<32>::Elf_Addr>*);
 737 #endif
 738
 739 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
 740 template
 741 void
 742 Object_merge_map::initialize_input_to_output_map<64>(
 743     unsigned int shndx,
 744     elfcpp::Elf_types<64>::Elf_Addr starting_address,
 745     Unordered_map<section_offset_type, elfcpp::Elf_types<64>::Elf_Addr>*);
 746 #endif
 747
 748 } // End namespace gold.