gold/merge.cc

   1 // merge.cc -- handle section merging for gold
   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 #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::lower_bound(map->entries.begin(), map->entries.end(),
 166                      entry, Input_merge_compare());
 167   if (p == map->entries.end() || p->input_offset > input_offset)
 168     {
 169       if (p == map->entries.begin())
 170         return false;
 171       --p;
 172       gold_assert(p->input_offset <= input_offset);
 173     }
 174
 175   if (input_offset - p->input_offset
 176       >= static_cast<section_offset_type>(p->length))
 177     return false;
 178
 179   *output_offset = p->output_offset;
 180   if (*output_offset != -1)
 181     *output_offset += (input_offset - p->input_offset);
 182   return true;
 183 }
 184
 185 // Return whether this is the merge map for section SHNDX.
 186
 187 inline bool
 188 Object_merge_map::is_merge_section_for(const Merge_map* merge_map,
 189                                        unsigned int shndx)
 190 {
 191   Input_merge_map* map = this->get_input_merge_map(shndx);
 192   return map != NULL && map->merge_map == merge_map;
 193 }
 194
 195 // Initialize a mapping from input offsets to output addresses.
 196
 197 template<int size>
 198 void
 199 Object_merge_map::initialize_input_to_output_map(
 200     unsigned int shndx,
 201     typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
 202     Unordered_map<section_offset_type,
 203                   typename elfcpp::Elf_types<size>::Elf_Addr>* initialize_map)
 204 {
 205   Input_merge_map* map = this->get_input_merge_map(shndx);
 206   gold_assert(map != NULL);
 207
 208   gold_assert(initialize_map->empty());
 209   // We know how many entries we are going to add.
 210   // reserve_unordered_map takes an expected count of buckets, not a
 211   // count of elements, so double it to try to reduce collisions.
 212   reserve_unordered_map(initialize_map, map->entries.size() * 2);
 213
 214   for (Input_merge_map::Entries::const_iterator p = map->entries.begin();
 215        p != map->entries.end();
 216        ++p)
 217     {
 218       section_offset_type output_offset = p->output_offset;
 219       if (output_offset != -1)
 220         output_offset += starting_address;
 221       else
 222         {
 223           // If we see a relocation against an address we have chosen
 224           // to discard, we relocate to zero.  FIXME: We could also
 225           // issue a warning in this case; that would require
 226           // reporting this somehow and checking it in the routines in
 227           // reloc.h.
 228           output_offset = 0;
 229         }
 230       initialize_map->insert(std::make_pair(p->input_offset, output_offset));
 231     }
 232 }
 233
 234 // Class Merge_map.
 235
 236 // Add a mapping for the bytes from OFFSET to OFFSET + LENGTH in input
 237 // section SHNDX in object OBJECT to an OUTPUT_OFFSET in merged data
 238 // in an output section.
 239
 240 void
 241 Merge_map::add_mapping(Relobj* object, unsigned int shndx,
 242                        section_offset_type offset, section_size_type length,
 243                        section_offset_type output_offset)
 244 {
 245   gold_assert(object != NULL);
 246   Object_merge_map* object_merge_map = object->merge_map();
 247   if (object_merge_map == NULL)
 248     {
 249       object_merge_map = new Object_merge_map();
 250       object->set_merge_map(object_merge_map);
 251     }
 252
 253   object_merge_map->add_mapping(this, shndx, offset, length, output_offset);
 254 }
 255
 256 // Return the output offset for an input address.  The input address
 257 // is at offset OFFSET in section SHNDX in OBJECT.  This sets
 258 // *OUTPUT_OFFSET to the offset in the merged data in the output
 259 // section.  This returns true if the mapping is known, false
 260 // otherwise.
 261
 262 bool
 263 Merge_map::get_output_offset(const Relobj* object, unsigned int shndx,
 264                              section_offset_type offset,
 265                              section_offset_type* output_offset) const
 266 {
 267   Object_merge_map* object_merge_map = object->merge_map();
 268   if (object_merge_map == NULL)
 269     return false;
 270   return object_merge_map->get_output_offset(this, shndx, offset,
 271                                              output_offset);
 272 }
 273
 274 // Return whether this is the merge section for SHNDX in OBJECT.
 275
 276 bool
 277 Merge_map::is_merge_section_for(const Relobj* object, unsigned int shndx) const
 278 {
 279   Object_merge_map* object_merge_map = object->merge_map();
 280   if (object_merge_map == NULL)
 281     return false;
 282   return object_merge_map->is_merge_section_for(this, shndx);
 283 }
 284
 285 // Class Output_merge_base.
 286
 287 // Return the output offset for an input offset.  The input address is
 288 // at offset OFFSET in section SHNDX in OBJECT.  If we know the
 289 // offset, set *POUTPUT and return true.  Otherwise return false.
 290
 291 bool
 292 Output_merge_base::do_output_offset(const Relobj* object,
 293                                     unsigned int shndx,
 294                                     section_offset_type offset,
 295                                     section_offset_type* poutput) const
 296 {
 297   return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
 298 }
 299
 300 // Return whether this is the merge section for SHNDX in OBJECT.
 301
 302 bool
 303 Output_merge_base::do_is_merge_section_for(const Relobj* object,
 304                                            unsigned int shndx) const
 305 {
 306   return this->merge_map_.is_merge_section_for(object, shndx);
 307 }
 308
 309 // Record a merged input section for script processing.
 310
 311 void
 312 Output_merge_base::record_input_section(Relobj* relobj, unsigned int shndx)
 313 {
 314   gold_assert(this->keeps_input_sections_ && relobj != NULL);
 315   // If this is the first input section, record it.  We need do this because
 316   // this->input_sections_ is unordered.
 317   if (this->first_relobj_ == NULL)
 318     {
 319       this->first_relobj_ = relobj;
 320       this->first_shndx_ = shndx;
 321     }
 322
 323   std::pair<Input_sections::iterator, bool> result =
 324     this->input_sections_.insert(Section_id(relobj, shndx));
 325   // We should insert a merge section once only.
 326   gold_assert(result.second);
 327 }
 328
 329 // Class Output_merge_data.
 330
 331 // Compute the hash code for a fixed-size constant.
 332
 333 size_t
 334 Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const
 335 {
 336   const unsigned char* p = this->pomd_->constant(k);
 337   section_size_type entsize =
 338     convert_to_section_size_type(this->pomd_->entsize());
 339
 340   // Fowler/Noll/Vo (FNV) hash (type FNV-1a).
 341   if (sizeof(size_t) == 8)
 342     {
 343       size_t result = static_cast<size_t>(14695981039346656037ULL);
 344       for (section_size_type i = 0; i < entsize; ++i)
 345         {
 346           result &= (size_t) *p++;
 347           result *= 1099511628211ULL;
 348         }
 349       return result;
 350     }
 351   else
 352     {
 353       size_t result = 2166136261UL;
 354       for (section_size_type i = 0; i < entsize; ++i)
 355         {
 356           result ^= (size_t) *p++;
 357           result *= 16777619UL;
 358         }
 359       return result;
 360     }
 361 }
 362
 363 // Return whether one hash table key equals another.
 364
 365 bool
 366 Output_merge_data::Merge_data_eq::operator()(Merge_data_key k1,
 367                                              Merge_data_key k2) const
 368 {
 369   const unsigned char* p1 = this->pomd_->constant(k1);
 370   const unsigned char* p2 = this->pomd_->constant(k2);
 371   return memcmp(p1, p2, this->pomd_->entsize()) == 0;
 372 }
 373
 374 // Add a constant to the end of the section contents.
 375
 376 void
 377 Output_merge_data::add_constant(const unsigned char* p)
 378 {
 379   section_size_type entsize = convert_to_section_size_type(this->entsize());
 380   section_size_type addralign =
 381     convert_to_section_size_type(this->addralign());
 382   section_size_type addsize = std::max(entsize, addralign);
 383   if (this->len_ + addsize > this->alc_)
 384     {
 385       if (this->alc_ == 0)
 386         this->alc_ = 128 * addsize;
 387       else
 388         this->alc_ *= 2;
 389       this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->alc_));
 390       if (this->p_ == NULL)
 391         gold_nomem();
 392     }
 393
 394   memcpy(this->p_ + this->len_, p, entsize);
 395   if (addsize > entsize)
 396     memset(this->p_ + this->len_ + entsize, 0, addsize - entsize);
 397   this->len_ += addsize;
 398 }
 399
 400 // Add the input section SHNDX in OBJECT to a merged output section
 401 // which holds fixed length constants.  Return whether we were able to
 402 // handle the section; if not, it will be linked as usual without
 403 // constant merging.
 404
 405 bool
 406 Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
 407 {
 408   section_size_type len;
 409   bool is_new;
 410   const unsigned char* p = object->decompressed_section_contents(shndx, &len,
 411                                                                  &is_new);
 412
 413   section_size_type entsize = convert_to_section_size_type(this->entsize());
 414
 415   if (len % entsize != 0)
 416     {
 417       if (is_new)
 418         delete[] p;
 419       return false;
 420     }
 421
 422   this->input_count_ += len / entsize;
 423
 424   for (section_size_type i = 0; i < len; i += entsize, p += entsize)
 425     {
 426       // Add the constant to the section contents.  If we find that it
 427       // is already in the hash table, we will remove it again.
 428       Merge_data_key k = this->len_;
 429       this->add_constant(p);
 430
 431       std::pair<Merge_data_hashtable::iterator, bool> ins =
 432         this->hashtable_.insert(k);
 433
 434       if (!ins.second)
 435         {
 436           // Key was already present.  Remove the copy we just added.
 437           this->len_ -= entsize;
 438           k = *ins.first;
 439         }
 440
 441       // Record the offset of this constant in the output section.
 442       this->add_mapping(object, shndx, i, entsize, k);
 443     }
 444
 445   // For script processing, we keep the input sections.
 446   if (this->keeps_input_sections())
 447     record_input_section(object, shndx);
 448
 449   if (is_new)
 450     delete[] p;
 451
 452   return true;
 453 }
 454
 455 // Set the final data size in a merged output section with fixed size
 456 // constants.
 457
 458 void
 459 Output_merge_data::set_final_data_size()
 460 {
 461   // Release the memory we don't need.
 462   this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->len_));
 463   // An Output_merge_data object may be empty and realloc is allowed
 464   // to return a NULL pointer in this case.  An Output_merge_data is empty
 465   // if all its input sections have sizes that are not multiples of entsize.
 466   gold_assert(this->p_ != NULL || this->len_ == 0);
 467   this->set_data_size(this->len_);
 468 }
 469
 470 // Write the data of a merged output section with fixed size constants
 471 // to the file.
 472
 473 void
 474 Output_merge_data::do_write(Output_file* of)
 475 {
 476   of->write(this->offset(), this->p_, this->len_);
 477 }
 478
 479 // Write the data to a buffer.
 480
 481 void
 482 Output_merge_data::do_write_to_buffer(unsigned char* buffer)
 483 {
 484   memcpy(buffer, this->p_, this->len_);
 485 }
 486
 487 // Print merge stats to stderr.
 488
 489 void
 490 Output_merge_data::do_print_merge_stats(const char* section_name)
 491 {
 492   fprintf(stderr,
 493           _("%s: %s merged constants size: %lu; input: %zu; output: %zu\n"),
 494           program_name, section_name,
 495           static_cast<unsigned long>(this->entsize()),
 496           this->input_count_, this->hashtable_.size());
 497 }
 498
 499 // Class Output_merge_string.
 500
 501 // Add an input section to a merged string section.
 502
 503 template<typename Char_type>
 504 bool
 505 Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
 506                                                      unsigned int shndx)
 507 {
 508   section_size_type len;
 509   bool is_new;
 510   const unsigned char* pdata = object->decompressed_section_contents(shndx,
 511                                                                      &len,
 512                                                                      &is_new);
 513
 514   const Char_type* p = reinterpret_cast<const Char_type*>(pdata);
 515   const Char_type* pend = p + len / sizeof(Char_type);
 516   const Char_type* pend0 = pend;
 517
 518   if (len % sizeof(Char_type) != 0)
 519     {
 520       object->error(_("mergeable string section length not multiple of "
 521                       "character size"));
 522       if (is_new)
 523         delete[] pdata;
 524       return false;
 525     }
 526
 527   if (pend[-1] != 0)
 528     {
 529       gold_warning(_("%s: last entry in mergeable string section '%s' "
 530                      "not null terminated"),
 531                    object->name().c_str(),
 532                    object->section_name(shndx).c_str());
 533       // Find the end of the last NULL-terminated string in the buffer.
 534       while (pend0 > p && pend0[-1] != 0)
 535         --pend0;
 536     }
 537
 538   Merged_strings_list* merged_strings_list =
 539       new Merged_strings_list(object, shndx);
 540   this->merged_strings_lists_.push_back(merged_strings_list);
 541   Merged_strings& merged_strings = merged_strings_list->merged_strings;
 542
 543   // Count the number of non-null strings in the section and size the list.
 544   size_t count = 0;
 545   for (const Char_type* pt = p, len = string_length(pt);
 546        pt < pend0;
 547        pt += len + 1)
 548     if (len != 0)
 549       ++count;
 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 < pend0)
 565     {
 566       size_t len = string_length(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   if (p < pend)
 582     {
 583       size_t len = pend - p;
 584
 585       Stringpool::Key key;
 586       this->stringpool_.add_with_length(p, len, true, &key);
 587
 588       merged_strings.push_back(Merged_string(i, key));
 589
 590       i += (len + 1) * sizeof(Char_type);
 591     }
 592
 593   // Record the last offset in the input section so that we can
 594   // compute the length of the last string.
 595   merged_strings.push_back(Merged_string(i, 0));
 596
 597   this->input_count_ += count;
 598   this->input_size_ += len;
 599
 600   if (has_misaligned_strings)
 601     gold_warning(_("%s: section %s contains incorrectly aligned strings;"
 602                    " the alignment of those strings won't be preserved"),
 603                  object->name().c_str(),
 604                  object->section_name(shndx).c_str());
 605
 606   // For script processing, we keep the input sections.
 607   if (this->keeps_input_sections())
 608     record_input_section(object, shndx);
 609
 610   if (is_new)
 611     delete[] pdata;
 612
 613   return true;
 614 }
 615
 616 // Finalize the mappings from the input sections to the output
 617 // section, and return the final data size.
 618
 619 template<typename Char_type>
 620 section_size_type
 621 Output_merge_string<Char_type>::finalize_merged_data()
 622 {
 623   this->stringpool_.set_string_offsets();
 624
 625   for (typename Merged_strings_lists::const_iterator l =
 626          this->merged_strings_lists_.begin();
 627        l != this->merged_strings_lists_.end();
 628        ++l)
 629     {
 630       section_offset_type last_input_offset = 0;
 631       section_offset_type last_output_offset = 0;
 632       for (typename Merged_strings::const_iterator p =
 633              (*l)->merged_strings.begin();
 634            p != (*l)->merged_strings.end();
 635            ++p)
 636         {
 637           section_size_type length = p->offset - last_input_offset;
 638           if (length > 0)
 639             this->add_mapping((*l)->object, (*l)->shndx, last_input_offset,
 640                               length, last_output_offset);
 641           last_input_offset = p->offset;
 642           if (p->stringpool_key != 0)
 643             last_output_offset =
 644                 this->stringpool_.get_offset_from_key(p->stringpool_key);
 645         }
 646       delete *l;
 647     }
 648
 649   // Save some memory.  This also ensures that this function will work
 650   // if called twice, as may happen if Layout::set_segment_offsets
 651   // finds a better alignment.
 652   this->merged_strings_lists_.clear();
 653
 654   return this->stringpool_.get_strtab_size();
 655 }
 656
 657 template<typename Char_type>
 658 void
 659 Output_merge_string<Char_type>::set_final_data_size()
 660 {
 661   const off_t final_data_size = this->finalize_merged_data();
 662   this->set_data_size(final_data_size);
 663 }
 664
 665 // Write out a merged string section.
 666
 667 template<typename Char_type>
 668 void
 669 Output_merge_string<Char_type>::do_write(Output_file* of)
 670 {
 671   this->stringpool_.write(of, this->offset());
 672 }
 673
 674 // Write a merged string section to a buffer.
 675
 676 template<typename Char_type>
 677 void
 678 Output_merge_string<Char_type>::do_write_to_buffer(unsigned char* buffer)
 679 {
 680   this->stringpool_.write_to_buffer(buffer, this->data_size());
 681 }
 682
 683 // Return the name of the types of string to use with
 684 // do_print_merge_stats.
 685
 686 template<typename Char_type>
 687 const char*
 688 Output_merge_string<Char_type>::string_name()
 689 {
 690   gold_unreachable();
 691   return NULL;
 692 }
 693
 694 template<>
 695 const char*
 696 Output_merge_string<char>::string_name()
 697 {
 698   return "strings";
 699 }
 700
 701 template<>
 702 const char*
 703 Output_merge_string<uint16_t>::string_name()
 704 {
 705   return "16-bit strings";
 706 }
 707
 708 template<>
 709 const char*
 710 Output_merge_string<uint32_t>::string_name()
 711 {
 712   return "32-bit strings";
 713 }
 714
 715 // Print merge stats to stderr.
 716
 717 template<typename Char_type>
 718 void
 719 Output_merge_string<Char_type>::do_print_merge_stats(const char* section_name)
 720 {
 721   char buf[200];
 722   snprintf(buf, sizeof buf, "%s merged %s", section_name, this->string_name());
 723   fprintf(stderr, _("%s: %s input bytes: %zu\n"),
 724           program_name, buf, this->input_size_);
 725   fprintf(stderr, _("%s: %s input strings: %zu\n"),
 726           program_name, buf, this->input_count_);
 727   this->stringpool_.print_stats(buf);
 728 }
 729
 730 // Instantiate the templates we need.
 731
 732 template
 733 class Output_merge_string<char>;
 734
 735 template
 736 class Output_merge_string<uint16_t>;
 737
 738 template
 739 class Output_merge_string<uint32_t>;
 740
 741 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
 742 template
 743 void
 744 Object_merge_map::initialize_input_to_output_map<32>(
 745     unsigned int shndx,
 746     elfcpp::Elf_types<32>::Elf_Addr starting_address,
 747     Unordered_map<section_offset_type, elfcpp::Elf_types<32>::Elf_Addr>*);
 748 #endif
 749
 750 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
 751 template
 752 void
 753 Object_merge_map::initialize_input_to_output_map<64>(
 754     unsigned int shndx,
 755     elfcpp::Elf_types<64>::Elf_Addr starting_address,
 756     Unordered_map<section_offset_type, elfcpp::Elf_types<64>::Elf_Addr>*);
 757 #endif
 758
 759 } // End namespace gold.