gold/layout.cc

   1 // layout.cc -- lay out output file sections for gold
   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 #include "gold.h"
  24
  25 #include <cerrno>
  26 #include <cstring>
  27 #include <algorithm>
  28 #include <iostream>
  29 #include <fstream>
  30 #include <utility>
  31 #include <fcntl.h>
  32 #include <fnmatch.h>
  33 #include <unistd.h>
  34 #include "libiberty.h"
  35 #include "md5.h"
  36 #include "sha1.h"
  37
  38 #include "parameters.h"
  39 #include "options.h"
  40 #include "mapfile.h"
  41 #include "script.h"
  42 #include "script-sections.h"
  43 #include "output.h"
  44 #include "symtab.h"
  45 #include "dynobj.h"
  46 #include "ehframe.h"
  47 #include "compressed_output.h"
  48 #include "reduced_debug_output.h"
  49 #include "reloc.h"
  50 #include "descriptors.h"
  51 #include "plugin.h"
  52 #include "incremental.h"
  53 #include "layout.h"
  54
  55 namespace gold
  56 {
  57
  58 // Layout::Relaxation_debug_check methods.
  59
  60 // Check that sections and special data are in reset states.
  61 // We do not save states for Output_sections and special Output_data.
  62 // So we check that they have not assigned any addresses or offsets.
  63 // clean_up_after_relaxation simply resets their addresses and offsets.
  64 void
  65 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
  66     const Layout::Section_list& sections,
  67     const Layout::Data_list& special_outputs)
  68 {
  69   for(Layout::Section_list::const_iterator p = sections.begin();
  70       p != sections.end();
  71       ++p)
  72     gold_assert((*p)->address_and_file_offset_have_reset_values());
  73
  74   for(Layout::Data_list::const_iterator p = special_outputs.begin();
  75       p != special_outputs.end();
  76       ++p)
  77     gold_assert((*p)->address_and_file_offset_have_reset_values());
  78 }
  79
  80 // Save information of SECTIONS for checking later.
  81
  82 void
  83 Layout::Relaxation_debug_check::read_sections(
  84     const Layout::Section_list& sections)
  85 {
  86   for(Layout::Section_list::const_iterator p = sections.begin();
  87       p != sections.end();
  88       ++p)
  89     {
  90       Output_section* os = *p;
  91       Section_info info;
  92       info.output_section = os;
  93       info.address = os->is_address_valid() ? os->address() : 0;
  94       info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
  95       info.offset = os->is_offset_valid()? os->offset() : -1 ;
  96       this->section_infos_.push_back(info);
  97     }
  98 }
  99
 100 // Verify SECTIONS using previously recorded information.
 101
 102 void
 103 Layout::Relaxation_debug_check::verify_sections(
 104     const Layout::Section_list& sections)
 105 {
 106   size_t i = 0;
 107   for(Layout::Section_list::const_iterator p = sections.begin();
 108       p != sections.end();
 109       ++p, ++i)
 110     {
 111       Output_section* os = *p;
 112       uint64_t address = os->is_address_valid() ? os->address() : 0;
 113       off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
 114       off_t offset = os->is_offset_valid()? os->offset() : -1 ;
 115
 116       if (i >= this->section_infos_.size())
 117         {
 118           gold_fatal("Section_info of %s missing.\n", os->name());
 119         }
 120       const Section_info& info = this->section_infos_[i];
 121       if (os != info.output_section)
 122         gold_fatal("Section order changed.  Expecting %s but see %s\n",
 123                    info.output_section->name(), os->name());
 124       if (address != info.address
 125           || data_size != info.data_size
 126           || offset != info.offset)
 127         gold_fatal("Section %s changed.\n", os->name());
 128     }
 129 }
 130
 131 // Layout_task_runner methods.
 132
 133 // Lay out the sections.  This is called after all the input objects
 134 // have been read.
 135
 136 void
 137 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
 138 {
 139   off_t file_size = this->layout_->finalize(this->input_objects_,
 140                                             this->symtab_,
 141                                             this->target_,
 142                                             task);
 143
 144   // Now we know the final size of the output file and we know where
 145   // each piece of information goes.
 146
 147   if (this->mapfile_ != NULL)
 148     {
 149       this->mapfile_->print_discarded_sections(this->input_objects_);
 150       this->layout_->print_to_mapfile(this->mapfile_);
 151     }
 152
 153   Output_file* of = new Output_file(parameters->options().output_file_name());
 154   if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
 155     of->set_is_temporary();
 156   of->open(file_size);
 157
 158   // Queue up the final set of tasks.
 159   gold::queue_final_tasks(this->options_, this->input_objects_,
 160                           this->symtab_, this->layout_, workqueue, of);
 161 }
 162
 163 // Layout methods.
 164
 165 Layout::Layout(int number_of_input_files, Script_options* script_options)
 166   : number_of_input_files_(number_of_input_files),
 167     script_options_(script_options),
 168     namepool_(),
 169     sympool_(),
 170     dynpool_(),
 171     signatures_(),
 172     section_name_map_(),
 173     segment_list_(),
 174     section_list_(),
 175     unattached_section_list_(),
 176     special_output_list_(),
 177     section_headers_(NULL),
 178     tls_segment_(NULL),
 179     relro_segment_(NULL),
 180     increase_relro_(0),
 181     symtab_section_(NULL),
 182     symtab_xindex_(NULL),
 183     dynsym_section_(NULL),
 184     dynsym_xindex_(NULL),
 185     dynamic_section_(NULL),
 186     dynamic_symbol_(NULL),
 187     dynamic_data_(NULL),
 188     eh_frame_section_(NULL),
 189     eh_frame_data_(NULL),
 190     added_eh_frame_data_(false),
 191     eh_frame_hdr_section_(NULL),
 192     build_id_note_(NULL),
 193     debug_abbrev_(NULL),
 194     debug_info_(NULL),
 195     group_signatures_(),
 196     output_file_size_(-1),
 197     have_added_input_section_(false),
 198     sections_are_attached_(false),
 199     input_requires_executable_stack_(false),
 200     input_with_gnu_stack_note_(false),
 201     input_without_gnu_stack_note_(false),
 202     has_static_tls_(false),
 203     any_postprocessing_sections_(false),
 204     resized_signatures_(false),
 205     have_stabstr_section_(false),
 206     incremental_inputs_(NULL),
 207     record_output_section_data_from_script_(false),
 208     script_output_section_data_list_(),
 209     segment_states_(NULL),
 210     relaxation_debug_check_(NULL)
 211 {
 212   // Make space for more than enough segments for a typical file.
 213   // This is just for efficiency--it's OK if we wind up needing more.
 214   this->segment_list_.reserve(12);
 215
 216   // We expect two unattached Output_data objects: the file header and
 217   // the segment headers.
 218   this->special_output_list_.reserve(2);
 219
 220   // Initialize structure needed for an incremental build.
 221   if (parameters->options().incremental())
 222     this->incremental_inputs_ = new Incremental_inputs;
 223
 224   // The section name pool is worth optimizing in all cases, because
 225   // it is small, but there are often overlaps due to .rel sections.
 226   this->namepool_.set_optimize();
 227 }
 228
 229 // Hash a key we use to look up an output section mapping.
 230
 231 size_t
 232 Layout::Hash_key::operator()(const Layout::Key& k) const
 233 {
 234  return k.first + k.second.first + k.second.second;
 235 }
 236
 237 // Returns whether the given section is in the list of
 238 // debug-sections-used-by-some-version-of-gdb.  Currently,
 239 // we've checked versions of gdb up to and including 6.7.1.
 240
 241 static const char* gdb_sections[] =
 242 { ".debug_abbrev",
 243   // ".debug_aranges",   // not used by gdb as of 6.7.1
 244   ".debug_frame",
 245   ".debug_info",
 246   ".debug_types",
 247   ".debug_line",
 248   ".debug_loc",
 249   ".debug_macinfo",
 250   // ".debug_pubnames",  // not used by gdb as of 6.7.1
 251   ".debug_ranges",
 252   ".debug_str",
 253 };
 254
 255 static const char* lines_only_debug_sections[] =
 256 { ".debug_abbrev",
 257   // ".debug_aranges",   // not used by gdb as of 6.7.1
 258   // ".debug_frame",
 259   ".debug_info",
 260   // ".debug_types",
 261   ".debug_line",
 262   // ".debug_loc",
 263   // ".debug_macinfo",
 264   // ".debug_pubnames",  // not used by gdb as of 6.7.1
 265   // ".debug_ranges",
 266   ".debug_str",
 267 };
 268
 269 static inline bool
 270 is_gdb_debug_section(const char* str)
 271 {
 272   // We can do this faster: binary search or a hashtable.  But why bother?
 273   for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
 274     if (strcmp(str, gdb_sections[i]) == 0)
 275       return true;
 276   return false;
 277 }
 278
 279 static inline bool
 280 is_lines_only_debug_section(const char* str)
 281 {
 282   // We can do this faster: binary search or a hashtable.  But why bother?
 283   for (size_t i = 0;
 284        i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
 285        ++i)
 286     if (strcmp(str, lines_only_debug_sections[i]) == 0)
 287       return true;
 288   return false;
 289 }
 290
 291 // Whether to include this section in the link.
 292
 293 template<int size, bool big_endian>
 294 bool
 295 Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
 296                         const elfcpp::Shdr<size, big_endian>& shdr)
 297 {
 298   if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
 299     return false;
 300
 301   switch (shdr.get_sh_type())
 302     {
 303     case elfcpp::SHT_NULL:
 304     case elfcpp::SHT_SYMTAB:
 305     case elfcpp::SHT_DYNSYM:
 306     case elfcpp::SHT_HASH:
 307     case elfcpp::SHT_DYNAMIC:
 308     case elfcpp::SHT_SYMTAB_SHNDX:
 309       return false;
 310
 311     case elfcpp::SHT_STRTAB:
 312       // Discard the sections which have special meanings in the ELF
 313       // ABI.  Keep others (e.g., .stabstr).  We could also do this by
 314       // checking the sh_link fields of the appropriate sections.
 315       return (strcmp(name, ".dynstr") != 0
 316               && strcmp(name, ".strtab") != 0
 317               && strcmp(name, ".shstrtab") != 0);
 318
 319     case elfcpp::SHT_RELA:
 320     case elfcpp::SHT_REL:
 321     case elfcpp::SHT_GROUP:
 322       // If we are emitting relocations these should be handled
 323       // elsewhere.
 324       gold_assert(!parameters->options().relocatable()
 325                   && !parameters->options().emit_relocs());
 326       return false;
 327
 328     case elfcpp::SHT_PROGBITS:
 329       if (parameters->options().strip_debug()
 330           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 331         {
 332           if (is_debug_info_section(name))
 333             return false;
 334         }
 335       if (parameters->options().strip_debug_non_line()
 336           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 337         {
 338           // Debugging sections can only be recognized by name.
 339           if (is_prefix_of(".debug", name)
 340               && !is_lines_only_debug_section(name))
 341             return false;
 342         }
 343       if (parameters->options().strip_debug_gdb()
 344           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 345         {
 346           // Debugging sections can only be recognized by name.
 347           if (is_prefix_of(".debug", name)
 348               && !is_gdb_debug_section(name))
 349             return false;
 350         }
 351       if (parameters->options().strip_lto_sections()
 352           && !parameters->options().relocatable()
 353           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
 354         {
 355           // Ignore LTO sections containing intermediate code.
 356           if (is_prefix_of(".gnu.lto_", name))
 357             return false;
 358         }
 359       // The GNU linker strips .gnu_debuglink sections, so we do too.
 360       // This is a feature used to keep debugging information in
 361       // separate files.
 362       if (strcmp(name, ".gnu_debuglink") == 0)
 363         return false;
 364       return true;
 365
 366     default:
 367       return true;
 368     }
 369 }
 370
 371 // Return an output section named NAME, or NULL if there is none.
 372
 373 Output_section*
 374 Layout::find_output_section(const char* name) const
 375 {
 376   for (Section_list::const_iterator p = this->section_list_.begin();
 377        p != this->section_list_.end();
 378        ++p)
 379     if (strcmp((*p)->name(), name) == 0)
 380       return *p;
 381   return NULL;
 382 }
 383
 384 // Return an output segment of type TYPE, with segment flags SET set
 385 // and segment flags CLEAR clear.  Return NULL if there is none.
 386
 387 Output_segment*
 388 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
 389                             elfcpp::Elf_Word clear) const
 390 {
 391   for (Segment_list::const_iterator p = this->segment_list_.begin();
 392        p != this->segment_list_.end();
 393        ++p)
 394     if (static_cast<elfcpp::PT>((*p)->type()) == type
 395         && ((*p)->flags() & set) == set
 396         && ((*p)->flags() & clear) == 0)
 397       return *p;
 398   return NULL;
 399 }
 400
 401 // Return the output section to use for section NAME with type TYPE
 402 // and section flags FLAGS.  NAME must be canonicalized in the string
 403 // pool, and NAME_KEY is the key.  IS_INTERP is true if this is the
 404 // .interp section.  IS_DYNAMIC_LINKER_SECTION is true if this section
 405 // is used by the dynamic linker.  IS_RELRO is true for a relro
 406 // section.  IS_LAST_RELRO is true for the last relro section.
 407 // IS_FIRST_NON_RELRO is true for the first non-relro section.
 408
 409 Output_section*
 410 Layout::get_output_section(const char* name, Stringpool::Key name_key,
 411                            elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
 412                            Output_section_order order, bool is_relro)
 413 {
 414   elfcpp::Elf_Xword lookup_flags = flags;
 415
 416   // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
 417   // read-write with read-only sections.  Some other ELF linkers do
 418   // not do this.  FIXME: Perhaps there should be an option
 419   // controlling this.
 420   lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
 421
 422   const Key key(name_key, std::make_pair(type, lookup_flags));
 423   const std::pair<Key, Output_section*> v(key, NULL);
 424   std::pair<Section_name_map::iterator, bool> ins(
 425     this->section_name_map_.insert(v));
 426
 427   if (!ins.second)
 428     return ins.first->second;
 429   else
 430     {
 431       // This is the first time we've seen this name/type/flags
 432       // combination.  For compatibility with the GNU linker, we
 433       // combine sections with contents and zero flags with sections
 434       // with non-zero flags.  This is a workaround for cases where
 435       // assembler code forgets to set section flags.  FIXME: Perhaps
 436       // there should be an option to control this.
 437       Output_section* os = NULL;
 438
 439       if (type == elfcpp::SHT_PROGBITS)
 440         {
 441           if (flags == 0)
 442             {
 443               Output_section* same_name = this->find_output_section(name);
 444               if (same_name != NULL
 445                   && same_name->type() == elfcpp::SHT_PROGBITS
 446                   && (same_name->flags() & elfcpp::SHF_TLS) == 0)
 447                 os = same_name;
 448             }
 449           else if ((flags & elfcpp::SHF_TLS) == 0)
 450             {
 451               elfcpp::Elf_Xword zero_flags = 0;
 452               const Key zero_key(name_key, std::make_pair(type, zero_flags));
 453               Section_name_map::iterator p =
 454                   this->section_name_map_.find(zero_key);
 455               if (p != this->section_name_map_.end())
 456                 os = p->second;
 457             }
 458         }
 459
 460       if (os == NULL)
 461         os = this->make_output_section(name, type, flags, order, is_relro);
 462
 463       ins.first->second = os;
 464       return os;
 465     }
 466 }
 467
 468 // Pick the output section to use for section NAME, in input file
 469 // RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
 470 // linker created section.  IS_INPUT_SECTION is true if we are
 471 // choosing an output section for an input section found in a input
 472 // file.  IS_INTERP is true if this is the .interp section.
 473 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
 474 // dynamic linker.  IS_RELRO is true for a relro section.
 475 // IS_LAST_RELRO is true for the last relro section.
 476 // IS_FIRST_NON_RELRO is true for the first non-relro section.  This
 477 // will return NULL if the input section should be discarded.
 478
 479 Output_section*
 480 Layout::choose_output_section(const Relobj* relobj, const char* name,
 481                               elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
 482                               bool is_input_section, Output_section_order order,
 483                               bool is_relro)
 484 {
 485   // We should not see any input sections after we have attached
 486   // sections to segments.
 487   gold_assert(!is_input_section || !this->sections_are_attached_);
 488
 489   // Some flags in the input section should not be automatically
 490   // copied to the output section.
 491   flags &= ~ (elfcpp::SHF_INFO_LINK
 492               | elfcpp::SHF_LINK_ORDER
 493               | elfcpp::SHF_GROUP
 494               | elfcpp::SHF_MERGE
 495               | elfcpp::SHF_STRINGS);
 496
 497   if (this->script_options_->saw_sections_clause())
 498     {
 499       // We are using a SECTIONS clause, so the output section is
 500       // chosen based only on the name.
 501
 502       Script_sections* ss = this->script_options_->script_sections();
 503       const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
 504       Output_section** output_section_slot;
 505       Script_sections::Section_type script_section_type;
 506       const char* orig_name = name;
 507       name = ss->output_section_name(file_name, name, &output_section_slot,
 508                                      &script_section_type);
 509       if (name == NULL)
 510         {
 511           gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
 512                                      "because it is not allowed by the "
 513                                      "SECTIONS clause of the linker script"),
 514                      orig_name);
 515           // The SECTIONS clause says to discard this input section.
 516           return NULL;
 517         }
 518
 519       // We can only handle script section types ST_NONE and ST_NOLOAD.
 520       switch (script_section_type)
 521         {
 522         case Script_sections::ST_NONE:
 523           break;
 524         case Script_sections::ST_NOLOAD:
 525           flags &= elfcpp::SHF_ALLOC;
 526           break;
 527         default:
 528           gold_unreachable();
 529         }
 530
 531       // If this is an orphan section--one not mentioned in the linker
 532       // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
 533       // default processing below.
 534
 535       if (output_section_slot != NULL)
 536         {
 537           if (*output_section_slot != NULL)
 538             {
 539               (*output_section_slot)->update_flags_for_input_section(flags);
 540               return *output_section_slot;
 541             }
 542
 543           // We don't put sections found in the linker script into
 544           // SECTION_NAME_MAP_.  That keeps us from getting confused
 545           // if an orphan section is mapped to a section with the same
 546           // name as one in the linker script.
 547
 548           name = this->namepool_.add(name, false, NULL);
 549
 550           Output_section* os = this->make_output_section(name, type, flags,
 551                                                          order, is_relro);
 552
 553           os->set_found_in_sections_clause();
 554
 555           // Special handling for NOLOAD sections.
 556           if (script_section_type == Script_sections::ST_NOLOAD)
 557             {
 558               os->set_is_noload();
 559
 560               // The constructor of Output_section sets addresses of non-ALLOC
 561               // sections to 0 by default.  We don't want that for NOLOAD
 562               // sections even if they have no SHF_ALLOC flag.
 563               if ((os->flags() & elfcpp::SHF_ALLOC) == 0
 564                   && os->is_address_valid())
 565                 {
 566                   gold_assert(os->address() == 0
 567                               && !os->is_offset_valid()
 568                               && !os->is_data_size_valid());
 569                   os->reset_address_and_file_offset();
 570                 }
 571             }
 572
 573           *output_section_slot = os;
 574           return os;
 575         }
 576     }
 577
 578   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
 579
 580   // Turn NAME from the name of the input section into the name of the
 581   // output section.
 582
 583   size_t len = strlen(name);
 584   if (is_input_section
 585       && !this->script_options_->saw_sections_clause()
 586       && !parameters->options().relocatable())
 587     name = Layout::output_section_name(name, &len);
 588
 589   Stringpool::Key name_key;
 590   name = this->namepool_.add_with_length(name, len, true, &name_key);
 591
 592   // Find or make the output section.  The output section is selected
 593   // based on the section name, type, and flags.
 594   return this->get_output_section(name, name_key, type, flags, order, is_relro);
 595 }
 596
 597 // Return the output section to use for input section SHNDX, with name
 598 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
 599 // index of a relocation section which applies to this section, or 0
 600 // if none, or -1U if more than one.  RELOC_TYPE is the type of the
 601 // relocation section if there is one.  Set *OFF to the offset of this
 602 // input section without the output section.  Return NULL if the
 603 // section should be discarded.  Set *OFF to -1 if the section
 604 // contents should not be written directly to the output file, but
 605 // will instead receive special handling.
 606
 607 template<int size, bool big_endian>
 608 Output_section*
 609 Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
 610                const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 611                unsigned int reloc_shndx, unsigned int, off_t* off)
 612 {
 613   *off = 0;
 614
 615   if (!this->include_section(object, name, shdr))
 616     return NULL;
 617
 618   Output_section* os;
 619
 620   // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
 621   // correct section types.  Force them here.
 622   elfcpp::Elf_Word sh_type = shdr.get_sh_type();
 623   if (sh_type == elfcpp::SHT_PROGBITS)
 624     {
 625       static const char init_array_prefix[] = ".init_array";
 626       static const char preinit_array_prefix[] = ".preinit_array";
 627       static const char fini_array_prefix[] = ".fini_array";
 628       static size_t init_array_prefix_size = sizeof(init_array_prefix) - 1;
 629       static size_t preinit_array_prefix_size =
 630         sizeof(preinit_array_prefix) - 1;
 631       static size_t fini_array_prefix_size = sizeof(fini_array_prefix) - 1;
 632
 633       if (strncmp(name, init_array_prefix, init_array_prefix_size) == 0)
 634         sh_type = elfcpp::SHT_INIT_ARRAY;
 635       else if (strncmp(name, preinit_array_prefix, preinit_array_prefix_size)
 636                == 0)
 637         sh_type = elfcpp::SHT_PREINIT_ARRAY;
 638       else if (strncmp(name, fini_array_prefix, fini_array_prefix_size) == 0)
 639         sh_type = elfcpp::SHT_FINI_ARRAY;
 640     }
 641
 642   // In a relocatable link a grouped section must not be combined with
 643   // any other sections.
 644   if (parameters->options().relocatable()
 645       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
 646     {
 647       name = this->namepool_.add(name, true, NULL);
 648       os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
 649                                      ORDER_INVALID, false);
 650     }
 651   else
 652     {
 653       os = this->choose_output_section(object, name, sh_type,
 654                                        shdr.get_sh_flags(), true,
 655                                        ORDER_INVALID, false);
 656       if (os == NULL)
 657         return NULL;
 658     }
 659
 660   // By default the GNU linker sorts input sections whose names match
 661   // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*.  The sections
 662   // are sorted by name.  This is used to implement constructor
 663   // priority ordering.  We are compatible.
 664   if (!this->script_options_->saw_sections_clause()
 665       && (is_prefix_of(".ctors.", name)
 666           || is_prefix_of(".dtors.", name)
 667           || is_prefix_of(".init_array.", name)
 668           || is_prefix_of(".fini_array.", name)))
 669     os->set_must_sort_attached_input_sections();
 670
 671   // FIXME: Handle SHF_LINK_ORDER somewhere.
 672
 673   *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
 674                                this->script_options_->saw_sections_clause());
 675   this->have_added_input_section_ = true;
 676
 677   return os;
 678 }
 679
 680 // Handle a relocation section when doing a relocatable link.
 681
 682 template<int size, bool big_endian>
 683 Output_section*
 684 Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
 685                      unsigned int,
 686                      const elfcpp::Shdr<size, big_endian>& shdr,
 687                      Output_section* data_section,
 688                      Relocatable_relocs* rr)
 689 {
 690   gold_assert(parameters->options().relocatable()
 691               || parameters->options().emit_relocs());
 692
 693   int sh_type = shdr.get_sh_type();
 694
 695   std::string name;
 696   if (sh_type == elfcpp::SHT_REL)
 697     name = ".rel";
 698   else if (sh_type == elfcpp::SHT_RELA)
 699     name = ".rela";
 700   else
 701     gold_unreachable();
 702   name += data_section->name();
 703
 704   // In a relocatable link relocs for a grouped section must not be
 705   // combined with other reloc sections.
 706   Output_section* os;
 707   if (!parameters->options().relocatable()
 708       || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
 709     os = this->choose_output_section(object, name.c_str(), sh_type,
 710                                      shdr.get_sh_flags(), false,
 711                                      ORDER_INVALID, false);
 712   else
 713     {
 714       const char* n = this->namepool_.add(name.c_str(), true, NULL);
 715       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
 716                                      ORDER_INVALID, false);
 717     }
 718
 719   os->set_should_link_to_symtab();
 720   os->set_info_section(data_section);
 721
 722   Output_section_data* posd;
 723   if (sh_type == elfcpp::SHT_REL)
 724     {
 725       os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
 726       posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
 727                                            size,
 728                                            big_endian>(rr);
 729     }
 730   else if (sh_type == elfcpp::SHT_RELA)
 731     {
 732       os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
 733       posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
 734                                            size,
 735                                            big_endian>(rr);
 736     }
 737   else
 738     gold_unreachable();
 739
 740   os->add_output_section_data(posd);
 741   rr->set_output_data(posd);
 742
 743   return os;
 744 }
 745
 746 // Handle a group section when doing a relocatable link.
 747
 748 template<int size, bool big_endian>
 749 void
 750 Layout::layout_group(Symbol_table* symtab,
 751                      Sized_relobj<size, big_endian>* object,
 752                      unsigned int,
 753                      const char* group_section_name,
 754                      const char* signature,
 755                      const elfcpp::Shdr<size, big_endian>& shdr,
 756                      elfcpp::Elf_Word flags,
 757                      std::vector<unsigned int>* shndxes)
 758 {
 759   gold_assert(parameters->options().relocatable());
 760   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
 761   group_section_name = this->namepool_.add(group_section_name, true, NULL);
 762   Output_section* os = this->make_output_section(group_section_name,
 763                                                  elfcpp::SHT_GROUP,
 764                                                  shdr.get_sh_flags(),
 765                                                  ORDER_INVALID, false);
 766
 767   // We need to find a symbol with the signature in the symbol table.
 768   // If we don't find one now, we need to look again later.
 769   Symbol* sym = symtab->lookup(signature, NULL);
 770   if (sym != NULL)
 771     os->set_info_symndx(sym);
 772   else
 773     {
 774       // Reserve some space to minimize reallocations.
 775       if (this->group_signatures_.empty())
 776         this->group_signatures_.reserve(this->number_of_input_files_ * 16);
 777
 778       // We will wind up using a symbol whose name is the signature.
 779       // So just put the signature in the symbol name pool to save it.
 780       signature = symtab->canonicalize_name(signature);
 781       this->group_signatures_.push_back(Group_signature(os, signature));
 782     }
 783
 784   os->set_should_link_to_symtab();
 785   os->set_entsize(4);
 786
 787   section_size_type entry_count =
 788     convert_to_section_size_type(shdr.get_sh_size() / 4);
 789   Output_section_data* posd =
 790     new Output_data_group<size, big_endian>(object, entry_count, flags,
 791                                             shndxes);
 792   os->add_output_section_data(posd);
 793 }
 794
 795 // Special GNU handling of sections name .eh_frame.  They will
 796 // normally hold exception frame data as defined by the C++ ABI
 797 // (http://codesourcery.com/cxx-abi/).
 798
 799 template<int size, bool big_endian>
 800 Output_section*
 801 Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
 802                         const unsigned char* symbols,
 803                         off_t symbols_size,
 804                         const unsigned char* symbol_names,
 805                         off_t symbol_names_size,
 806                         unsigned int shndx,
 807                         const elfcpp::Shdr<size, big_endian>& shdr,
 808                         unsigned int reloc_shndx, unsigned int reloc_type,
 809                         off_t* off)
 810 {
 811   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
 812   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
 813
 814   const char* const name = ".eh_frame";
 815   Output_section* os = this->choose_output_section(object, name,
 816                                                    elfcpp::SHT_PROGBITS,
 817                                                    elfcpp::SHF_ALLOC, false,
 818                                                    ORDER_EHFRAME, false);
 819   if (os == NULL)
 820     return NULL;
 821
 822   if (this->eh_frame_section_ == NULL)
 823     {
 824       this->eh_frame_section_ = os;
 825       this->eh_frame_data_ = new Eh_frame();
 826
 827       if (parameters->options().eh_frame_hdr())
 828         {
 829           Output_section* hdr_os =
 830             this->choose_output_section(NULL, ".eh_frame_hdr",
 831                                         elfcpp::SHT_PROGBITS,
 832                                         elfcpp::SHF_ALLOC, false,
 833                                         ORDER_EHFRAME, false);
 834
 835           if (hdr_os != NULL)
 836             {
 837               Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
 838                                                         this->eh_frame_data_);
 839               hdr_os->add_output_section_data(hdr_posd);
 840
 841               hdr_os->set_after_input_sections();
 842
 843               if (!this->script_options_->saw_phdrs_clause())
 844                 {
 845                   Output_segment* hdr_oseg;
 846                   hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
 847                                                        elfcpp::PF_R);
 848                   hdr_oseg->add_output_section_to_nonload(hdr_os,
 849                                                           elfcpp::PF_R);
 850                 }
 851
 852               this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
 853             }
 854         }
 855     }
 856
 857   gold_assert(this->eh_frame_section_ == os);
 858
 859   if (this->eh_frame_data_->add_ehframe_input_section(object,
 860                                                       symbols,
 861                                                       symbols_size,
 862                                                       symbol_names,
 863                                                       symbol_names_size,
 864                                                       shndx,
 865                                                       reloc_shndx,
 866                                                       reloc_type))
 867     {
 868       os->update_flags_for_input_section(shdr.get_sh_flags());
 869
 870       // We found a .eh_frame section we are going to optimize, so now
 871       // we can add the set of optimized sections to the output
 872       // section.  We need to postpone adding this until we've found a
 873       // section we can optimize so that the .eh_frame section in
 874       // crtbegin.o winds up at the start of the output section.
 875       if (!this->added_eh_frame_data_)
 876         {
 877           os->add_output_section_data(this->eh_frame_data_);
 878           this->added_eh_frame_data_ = true;
 879         }
 880       *off = -1;
 881     }
 882   else
 883     {
 884       // We couldn't handle this .eh_frame section for some reason.
 885       // Add it as a normal section.
 886       bool saw_sections_clause = this->script_options_->saw_sections_clause();
 887       *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
 888                                    saw_sections_clause);
 889       this->have_added_input_section_ = true;
 890     }
 891
 892   return os;
 893 }
 894
 895 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
 896 // the output section.
 897
 898 Output_section*
 899 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
 900                                 elfcpp::Elf_Xword flags,
 901                                 Output_section_data* posd,
 902                                 Output_section_order order, bool is_relro)
 903 {
 904   Output_section* os = this->choose_output_section(NULL, name, type, flags,
 905                                                    false, order, is_relro);
 906   if (os != NULL)
 907     os->add_output_section_data(posd);
 908   return os;
 909 }
 910
 911 // Map section flags to segment flags.
 912
 913 elfcpp::Elf_Word
 914 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
 915 {
 916   elfcpp::Elf_Word ret = elfcpp::PF_R;
 917   if ((flags & elfcpp::SHF_WRITE) != 0)
 918     ret |= elfcpp::PF_W;
 919   if ((flags & elfcpp::SHF_EXECINSTR) != 0)
 920     ret |= elfcpp::PF_X;
 921   return ret;
 922 }
 923
 924 // Sometimes we compress sections.  This is typically done for
 925 // sections that are not part of normal program execution (such as
 926 // .debug_* sections), and where the readers of these sections know
 927 // how to deal with compressed sections.  This routine doesn't say for
 928 // certain whether we'll compress -- it depends on commandline options
 929 // as well -- just whether this section is a candidate for compression.
 930 // (The Output_compressed_section class decides whether to compress
 931 // a given section, and picks the name of the compressed section.)
 932
 933 static bool
 934 is_compressible_debug_section(const char* secname)
 935 {
 936   return (is_prefix_of(".debug", secname));
 937 }
 938
 939 // We may see compressed debug sections in input files.  Return TRUE
 940 // if this is the name of a compressed debug section.
 941
 942 bool
 943 is_compressed_debug_section(const char* secname)
 944 {
 945   return (is_prefix_of(".zdebug", secname));
 946 }
 947
 948 // Make a new Output_section, and attach it to segments as
 949 // appropriate.  ORDER is the order in which this section should
 950 // appear in the output segment.  IS_RELRO is true if this is a relro
 951 // (read-only after relocations) section.
 952
 953 Output_section*
 954 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
 955                             elfcpp::Elf_Xword flags,
 956                             Output_section_order order, bool is_relro)
 957 {
 958   Output_section* os;
 959   if ((flags & elfcpp::SHF_ALLOC) == 0
 960       && strcmp(parameters->options().compress_debug_sections(), "none") != 0
 961       && is_compressible_debug_section(name))
 962     os = new Output_compressed_section(&parameters->options(), name, type,
 963                                        flags);
 964   else if ((flags & elfcpp::SHF_ALLOC) == 0
 965            && parameters->options().strip_debug_non_line()
 966            && strcmp(".debug_abbrev", name) == 0)
 967     {
 968       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
 969           name, type, flags);
 970       if (this->debug_info_)
 971         this->debug_info_->set_abbreviations(this->debug_abbrev_);
 972     }
 973   else if ((flags & elfcpp::SHF_ALLOC) == 0
 974            && parameters->options().strip_debug_non_line()
 975            && strcmp(".debug_info", name) == 0)
 976     {
 977       os = this->debug_info_ = new Output_reduced_debug_info_section(
 978           name, type, flags);
 979       if (this->debug_abbrev_)
 980         this->debug_info_->set_abbreviations(this->debug_abbrev_);
 981     }
 982   else
 983     {
 984       // FIXME: const_cast is ugly.
 985       Target* target = const_cast<Target*>(&parameters->target());
 986       os = target->make_output_section(name, type, flags);
 987     }
 988
 989   // With -z relro, we have to recognize the special sections by name.
 990   // There is no other way.
 991   bool is_relro_local = false;
 992   if (!this->script_options_->saw_sections_clause()
 993       && parameters->options().relro()
 994       && type == elfcpp::SHT_PROGBITS
 995       && (flags & elfcpp::SHF_ALLOC) != 0
 996       && (flags & elfcpp::SHF_WRITE) != 0)
 997     {
 998       if (strcmp(name, ".data.rel.ro") == 0)
 999         is_relro = true;
1000       else if (strcmp(name, ".data.rel.ro.local") == 0)
1001         {
1002           is_relro = true;
1003           is_relro_local = true;
1004         }
1005       else if (type == elfcpp::SHT_INIT_ARRAY
1006                || type == elfcpp::SHT_FINI_ARRAY
1007                || type == elfcpp::SHT_PREINIT_ARRAY)
1008         is_relro = true;
1009       else if (strcmp(name, ".ctors") == 0
1010                || strcmp(name, ".dtors") == 0
1011                || strcmp(name, ".jcr") == 0)
1012         is_relro = true;
1013     }
1014
1015   if (is_relro)
1016     os->set_is_relro();
1017
1018   if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1019     order = this->default_section_order(os, is_relro_local);
1020
1021   os->set_order(order);
1022
1023   parameters->target().new_output_section(os);
1024
1025   this->section_list_.push_back(os);
1026
1027   // The GNU linker by default sorts some sections by priority, so we
1028   // do the same.  We need to know that this might happen before we
1029   // attach any input sections.
1030   if (!this->script_options_->saw_sections_clause()
1031       && (strcmp(name, ".ctors") == 0
1032           || strcmp(name, ".dtors") == 0
1033           || strcmp(name, ".init_array") == 0
1034           || strcmp(name, ".fini_array") == 0))
1035     os->set_may_sort_attached_input_sections();
1036
1037   // Check for .stab*str sections, as .stab* sections need to link to
1038   // them.
1039   if (type == elfcpp::SHT_STRTAB
1040       && !this->have_stabstr_section_
1041       && strncmp(name, ".stab", 5) == 0
1042       && strcmp(name + strlen(name) - 3, "str") == 0)
1043     this->have_stabstr_section_ = true;
1044
1045   // If we have already attached the sections to segments, then we
1046   // need to attach this one now.  This happens for sections created
1047   // directly by the linker.
1048   if (this->sections_are_attached_)
1049     this->attach_section_to_segment(os);
1050
1051   return os;
1052 }
1053
1054 // Return the default order in which a section should be placed in an
1055 // output segment.  This function captures a lot of the ideas in
1056 // ld/scripttempl/elf.sc in the GNU linker.  Note that the order of a
1057 // linker created section is normally set when the section is created;
1058 // this function is used for input sections.
1059
1060 Output_section_order
1061 Layout::default_section_order(Output_section* os, bool is_relro_local)
1062 {
1063   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1064   bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1065   bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1066   bool is_bss = false;
1067
1068   switch (os->type())
1069     {
1070     default:
1071     case elfcpp::SHT_PROGBITS:
1072       break;
1073     case elfcpp::SHT_NOBITS:
1074       is_bss = true;
1075       break;
1076     case elfcpp::SHT_RELA:
1077     case elfcpp::SHT_REL:
1078       if (!is_write)
1079         return ORDER_DYNAMIC_RELOCS;
1080       break;
1081     case elfcpp::SHT_HASH:
1082     case elfcpp::SHT_DYNAMIC:
1083     case elfcpp::SHT_SHLIB:
1084     case elfcpp::SHT_DYNSYM:
1085     case elfcpp::SHT_GNU_HASH:
1086     case elfcpp::SHT_GNU_verdef:
1087     case elfcpp::SHT_GNU_verneed:
1088     case elfcpp::SHT_GNU_versym:
1089       if (!is_write)
1090         return ORDER_DYNAMIC_LINKER;
1091       break;
1092     case elfcpp::SHT_NOTE:
1093       return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1094     }
1095
1096   if ((os->flags() & elfcpp::SHF_TLS) != 0)
1097     return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1098
1099   if (!is_bss && !is_write)
1100     {
1101       if (is_execinstr)
1102         {
1103           if (strcmp(os->name(), ".init") == 0)
1104             return ORDER_INIT;
1105           else if (strcmp(os->name(), ".fini") == 0)
1106             return ORDER_FINI;
1107         }
1108       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1109     }
1110
1111   if (os->is_relro())
1112     return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1113
1114   if (os->is_small_section())
1115     return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1116   if (os->is_large_section())
1117     return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1118
1119   return is_bss ? ORDER_BSS : ORDER_DATA;
1120 }
1121
1122 // Attach output sections to segments.  This is called after we have
1123 // seen all the input sections.
1124
1125 void
1126 Layout::attach_sections_to_segments()
1127 {
1128   for (Section_list::iterator p = this->section_list_.begin();
1129        p != this->section_list_.end();
1130        ++p)
1131     this->attach_section_to_segment(*p);
1132
1133   this->sections_are_attached_ = true;
1134 }
1135
1136 // Attach an output section to a segment.
1137
1138 void
1139 Layout::attach_section_to_segment(Output_section* os)
1140 {
1141   if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1142     this->unattached_section_list_.push_back(os);
1143   else
1144     this->attach_allocated_section_to_segment(os);
1145 }
1146
1147 // Attach an allocated output section to a segment.
1148
1149 void
1150 Layout::attach_allocated_section_to_segment(Output_section* os)
1151 {
1152   elfcpp::Elf_Xword flags = os->flags();
1153   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1154
1155   if (parameters->options().relocatable())
1156     return;
1157
1158   // If we have a SECTIONS clause, we can't handle the attachment to
1159   // segments until after we've seen all the sections.
1160   if (this->script_options_->saw_sections_clause())
1161     return;
1162
1163   gold_assert(!this->script_options_->saw_phdrs_clause());
1164
1165   // This output section goes into a PT_LOAD segment.
1166
1167   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1168
1169   // Check for --section-start.
1170   uint64_t addr;
1171   bool is_address_set = parameters->options().section_start(os->name(), &addr);
1172
1173   // In general the only thing we really care about for PT_LOAD
1174   // segments is whether or not they are writable, so that is how we
1175   // search for them.  Large data sections also go into their own
1176   // PT_LOAD segment.  People who need segments sorted on some other
1177   // basis will have to use a linker script.
1178
1179   Segment_list::const_iterator p;
1180   for (p = this->segment_list_.begin();
1181        p != this->segment_list_.end();
1182        ++p)
1183     {
1184       if ((*p)->type() != elfcpp::PT_LOAD)
1185         continue;
1186       if (!parameters->options().omagic()
1187           && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1188         continue;
1189       // If -Tbss was specified, we need to separate the data and BSS
1190       // segments.
1191       if (parameters->options().user_set_Tbss())
1192         {
1193           if ((os->type() == elfcpp::SHT_NOBITS)
1194               == (*p)->has_any_data_sections())
1195             continue;
1196         }
1197       if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1198         continue;
1199
1200       if (is_address_set)
1201         {
1202           if ((*p)->are_addresses_set())
1203             continue;
1204
1205           (*p)->add_initial_output_data(os);
1206           (*p)->update_flags_for_output_section(seg_flags);
1207           (*p)->set_addresses(addr, addr);
1208           break;
1209         }
1210
1211       (*p)->add_output_section_to_load(this, os, seg_flags);
1212       break;
1213     }
1214
1215   if (p == this->segment_list_.end())
1216     {
1217       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1218                                                        seg_flags);
1219       if (os->is_large_data_section())
1220         oseg->set_is_large_data_segment();
1221       oseg->add_output_section_to_load(this, os, seg_flags);
1222       if (is_address_set)
1223         oseg->set_addresses(addr, addr);
1224     }
1225
1226   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1227   // segment.
1228   if (os->type() == elfcpp::SHT_NOTE)
1229     {
1230       // See if we already have an equivalent PT_NOTE segment.
1231       for (p = this->segment_list_.begin();
1232            p != segment_list_.end();
1233            ++p)
1234         {
1235           if ((*p)->type() == elfcpp::PT_NOTE
1236               && (((*p)->flags() & elfcpp::PF_W)
1237                   == (seg_flags & elfcpp::PF_W)))
1238             {
1239               (*p)->add_output_section_to_nonload(os, seg_flags);
1240               break;
1241             }
1242         }
1243
1244       if (p == this->segment_list_.end())
1245         {
1246           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1247                                                            seg_flags);
1248           oseg->add_output_section_to_nonload(os, seg_flags);
1249         }
1250     }
1251
1252   // If we see a loadable SHF_TLS section, we create a PT_TLS
1253   // segment.  There can only be one such segment.
1254   if ((flags & elfcpp::SHF_TLS) != 0)
1255     {
1256       if (this->tls_segment_ == NULL)
1257         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1258       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1259     }
1260
1261   // If -z relro is in effect, and we see a relro section, we create a
1262   // PT_GNU_RELRO segment.  There can only be one such segment.
1263   if (os->is_relro() && parameters->options().relro())
1264     {
1265       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1266       if (this->relro_segment_ == NULL)
1267         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1268       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1269     }
1270 }
1271
1272 // Make an output section for a script.
1273
1274 Output_section*
1275 Layout::make_output_section_for_script(
1276     const char* name,
1277     Script_sections::Section_type section_type)
1278 {
1279   name = this->namepool_.add(name, false, NULL);
1280   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1281   if (section_type == Script_sections::ST_NOLOAD)
1282     sh_flags = 0;
1283   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1284                                                  sh_flags, ORDER_INVALID,
1285                                                  false);
1286   os->set_found_in_sections_clause();
1287   if (section_type == Script_sections::ST_NOLOAD)
1288     os->set_is_noload();
1289   return os;
1290 }
1291
1292 // Return the number of segments we expect to see.
1293
1294 size_t
1295 Layout::expected_segment_count() const
1296 {
1297   size_t ret = this->segment_list_.size();
1298
1299   // If we didn't see a SECTIONS clause in a linker script, we should
1300   // already have the complete list of segments.  Otherwise we ask the
1301   // SECTIONS clause how many segments it expects, and add in the ones
1302   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1303
1304   if (!this->script_options_->saw_sections_clause())
1305     return ret;
1306   else
1307     {
1308       const Script_sections* ss = this->script_options_->script_sections();
1309       return ret + ss->expected_segment_count(this);
1310     }
1311 }
1312
1313 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
1314 // is whether we saw a .note.GNU-stack section in the object file.
1315 // GNU_STACK_FLAGS is the section flags.  The flags give the
1316 // protection required for stack memory.  We record this in an
1317 // executable as a PT_GNU_STACK segment.  If an object file does not
1318 // have a .note.GNU-stack segment, we must assume that it is an old
1319 // object.  On some targets that will force an executable stack.
1320
1321 void
1322 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
1323 {
1324   if (!seen_gnu_stack)
1325     this->input_without_gnu_stack_note_ = true;
1326   else
1327     {
1328       this->input_with_gnu_stack_note_ = true;
1329       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1330         this->input_requires_executable_stack_ = true;
1331     }
1332 }
1333
1334 // Create automatic note sections.
1335
1336 void
1337 Layout::create_notes()
1338 {
1339   this->create_gold_note();
1340   this->create_executable_stack_info();
1341   this->create_build_id();
1342 }
1343
1344 // Create the dynamic sections which are needed before we read the
1345 // relocs.
1346
1347 void
1348 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1349 {
1350   if (parameters->doing_static_link())
1351     return;
1352
1353   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1354                                                        elfcpp::SHT_DYNAMIC,
1355                                                        (elfcpp::SHF_ALLOC
1356                                                         | elfcpp::SHF_WRITE),
1357                                                        false, ORDER_RELRO,
1358                                                        true);
1359
1360   this->dynamic_symbol_ =
1361     symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
1362                                   this->dynamic_section_, 0, 0,
1363                                   elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1364                                   elfcpp::STV_HIDDEN, 0, false, false);
1365
1366   this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
1367
1368   this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1369 }
1370
1371 // For each output section whose name can be represented as C symbol,
1372 // define __start and __stop symbols for the section.  This is a GNU
1373 // extension.
1374
1375 void
1376 Layout::define_section_symbols(Symbol_table* symtab)
1377 {
1378   for (Section_list::const_iterator p = this->section_list_.begin();
1379        p != this->section_list_.end();
1380        ++p)
1381     {
1382       const char* const name = (*p)->name();
1383       if (is_cident(name))
1384         {
1385           const std::string name_string(name);
1386           const std::string start_name(cident_section_start_prefix
1387                                        + name_string);
1388           const std::string stop_name(cident_section_stop_prefix
1389                                       + name_string);
1390
1391           symtab->define_in_output_data(start_name.c_str(),
1392                                         NULL, // version
1393                                         Symbol_table::PREDEFINED,
1394                                         *p,
1395                                         0, // value
1396                                         0, // symsize
1397                                         elfcpp::STT_NOTYPE,
1398                                         elfcpp::STB_GLOBAL,
1399                                         elfcpp::STV_DEFAULT,
1400                                         0, // nonvis
1401                                         false, // offset_is_from_end
1402                                         true); // only_if_ref
1403
1404           symtab->define_in_output_data(stop_name.c_str(),
1405                                         NULL, // version
1406                                         Symbol_table::PREDEFINED,
1407                                         *p,
1408                                         0, // value
1409                                         0, // symsize
1410                                         elfcpp::STT_NOTYPE,
1411                                         elfcpp::STB_GLOBAL,
1412                                         elfcpp::STV_DEFAULT,
1413                                         0, // nonvis
1414                                         true, // offset_is_from_end
1415                                         true); // only_if_ref
1416         }
1417     }
1418 }
1419
1420 // Define symbols for group signatures.
1421
1422 void
1423 Layout::define_group_signatures(Symbol_table* symtab)
1424 {
1425   for (Group_signatures::iterator p = this->group_signatures_.begin();
1426        p != this->group_signatures_.end();
1427        ++p)
1428     {
1429       Symbol* sym = symtab->lookup(p->signature, NULL);
1430       if (sym != NULL)
1431         p->section->set_info_symndx(sym);
1432       else
1433         {
1434           // Force the name of the group section to the group
1435           // signature, and use the group's section symbol as the
1436           // signature symbol.
1437           if (strcmp(p->section->name(), p->signature) != 0)
1438             {
1439               const char* name = this->namepool_.add(p->signature,
1440                                                      true, NULL);
1441               p->section->set_name(name);
1442             }
1443           p->section->set_needs_symtab_index();
1444           p->section->set_info_section_symndx(p->section);
1445         }
1446     }
1447
1448   this->group_signatures_.clear();
1449 }
1450
1451 // Find the first read-only PT_LOAD segment, creating one if
1452 // necessary.
1453
1454 Output_segment*
1455 Layout::find_first_load_seg()
1456 {
1457   for (Segment_list::const_iterator p = this->segment_list_.begin();
1458        p != this->segment_list_.end();
1459        ++p)
1460     {
1461       if ((*p)->type() == elfcpp::PT_LOAD
1462           && ((*p)->flags() & elfcpp::PF_R) != 0
1463           && (parameters->options().omagic()
1464               || ((*p)->flags() & elfcpp::PF_W) == 0))
1465         return *p;
1466     }
1467
1468   gold_assert(!this->script_options_->saw_phdrs_clause());
1469
1470   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1471                                                        elfcpp::PF_R);
1472   return load_seg;
1473 }
1474
1475 // Save states of all current output segments.  Store saved states
1476 // in SEGMENT_STATES.
1477
1478 void
1479 Layout::save_segments(Segment_states* segment_states)
1480 {
1481   for (Segment_list::const_iterator p = this->segment_list_.begin();
1482        p != this->segment_list_.end();
1483        ++p)
1484     {
1485       Output_segment* segment = *p;
1486       // Shallow copy.
1487       Output_segment* copy = new Output_segment(*segment);
1488       (*segment_states)[segment] = copy;
1489     }
1490 }
1491
1492 // Restore states of output segments and delete any segment not found in
1493 // SEGMENT_STATES.
1494
1495 void
1496 Layout::restore_segments(const Segment_states* segment_states)
1497 {
1498   // Go through the segment list and remove any segment added in the
1499   // relaxation loop.
1500   this->tls_segment_ = NULL;
1501   this->relro_segment_ = NULL;
1502   Segment_list::iterator list_iter = this->segment_list_.begin();
1503   while (list_iter != this->segment_list_.end())
1504     {
1505       Output_segment* segment = *list_iter;
1506       Segment_states::const_iterator states_iter =
1507           segment_states->find(segment);
1508       if (states_iter != segment_states->end())
1509         {
1510           const Output_segment* copy = states_iter->second;
1511           // Shallow copy to restore states.
1512           *segment = *copy;
1513
1514           // Also fix up TLS and RELRO segment pointers as appropriate.
1515           if (segment->type() == elfcpp::PT_TLS)
1516             this->tls_segment_ = segment;
1517           else if (segment->type() == elfcpp::PT_GNU_RELRO)
1518             this->relro_segment_ = segment;
1519
1520           ++list_iter;
1521         }
1522       else
1523         {
1524           list_iter = this->segment_list_.erase(list_iter);
1525           // This is a segment created during section layout.  It should be
1526           // safe to remove it since we should have removed all pointers to it.
1527           delete segment;
1528         }
1529     }
1530 }
1531
1532 // Clean up after relaxation so that sections can be laid out again.
1533
1534 void
1535 Layout::clean_up_after_relaxation()
1536 {
1537   // Restore the segments to point state just prior to the relaxation loop.
1538   Script_sections* script_section = this->script_options_->script_sections();
1539   script_section->release_segments();
1540   this->restore_segments(this->segment_states_);
1541
1542   // Reset section addresses and file offsets
1543   for (Section_list::iterator p = this->section_list_.begin();
1544        p != this->section_list_.end();
1545        ++p)
1546     {
1547       (*p)->restore_states();
1548
1549       // If an input section changes size because of relaxation,
1550       // we need to adjust the section offsets of all input sections.
1551       // after such a section.
1552       if ((*p)->section_offsets_need_adjustment())
1553         (*p)->adjust_section_offsets();
1554
1555       (*p)->reset_address_and_file_offset();
1556     }
1557
1558   // Reset special output object address and file offsets.
1559   for (Data_list::iterator p = this->special_output_list_.begin();
1560        p != this->special_output_list_.end();
1561        ++p)
1562     (*p)->reset_address_and_file_offset();
1563
1564   // A linker script may have created some output section data objects.
1565   // They are useless now.
1566   for (Output_section_data_list::const_iterator p =
1567          this->script_output_section_data_list_.begin();
1568        p != this->script_output_section_data_list_.end();
1569        ++p)
1570     delete *p;
1571   this->script_output_section_data_list_.clear();
1572 }
1573
1574 // Prepare for relaxation.
1575
1576 void
1577 Layout::prepare_for_relaxation()
1578 {
1579   // Create an relaxation debug check if in debugging mode.
1580   if (is_debugging_enabled(DEBUG_RELAXATION))
1581     this->relaxation_debug_check_ = new Relaxation_debug_check();
1582
1583   // Save segment states.
1584   this->segment_states_ = new Segment_states();
1585   this->save_segments(this->segment_states_);
1586
1587   for(Section_list::const_iterator p = this->section_list_.begin();
1588       p != this->section_list_.end();
1589       ++p)
1590     (*p)->save_states();
1591
1592   if (is_debugging_enabled(DEBUG_RELAXATION))
1593     this->relaxation_debug_check_->check_output_data_for_reset_values(
1594         this->section_list_, this->special_output_list_);
1595
1596   // Also enable recording of output section data from scripts.
1597   this->record_output_section_data_from_script_ = true;
1598 }
1599
1600 // Relaxation loop body:  If target has no relaxation, this runs only once
1601 // Otherwise, the target relaxation hook is called at the end of
1602 // each iteration.  If the hook returns true, it means re-layout of
1603 // section is required.
1604 //
1605 // The number of segments created by a linking script without a PHDRS
1606 // clause may be affected by section sizes and alignments.  There is
1607 // a remote chance that relaxation causes different number of PT_LOAD
1608 // segments are created and sections are attached to different segments.
1609 // Therefore, we always throw away all segments created during section
1610 // layout.  In order to be able to restart the section layout, we keep
1611 // a copy of the segment list right before the relaxation loop and use
1612 // that to restore the segments.
1613 //
1614 // PASS is the current relaxation pass number.
1615 // SYMTAB is a symbol table.
1616 // PLOAD_SEG is the address of a pointer for the load segment.
1617 // PHDR_SEG is a pointer to the PHDR segment.
1618 // SEGMENT_HEADERS points to the output segment header.
1619 // FILE_HEADER points to the output file header.
1620 // PSHNDX is the address to store the output section index.
1621
1622 off_t inline
1623 Layout::relaxation_loop_body(
1624     int pass,
1625     Target* target,
1626     Symbol_table* symtab,
1627     Output_segment** pload_seg,
1628     Output_segment* phdr_seg,
1629     Output_segment_headers* segment_headers,
1630     Output_file_header* file_header,
1631     unsigned int* pshndx)
1632 {
1633   // If this is not the first iteration, we need to clean up after
1634   // relaxation so that we can lay out the sections again.
1635   if (pass != 0)
1636     this->clean_up_after_relaxation();
1637
1638   // If there is a SECTIONS clause, put all the input sections into
1639   // the required order.
1640   Output_segment* load_seg;
1641   if (this->script_options_->saw_sections_clause())
1642     load_seg = this->set_section_addresses_from_script(symtab);
1643   else if (parameters->options().relocatable())
1644     load_seg = NULL;
1645   else
1646     load_seg = this->find_first_load_seg();
1647
1648   if (parameters->options().oformat_enum()
1649       != General_options::OBJECT_FORMAT_ELF)
1650     load_seg = NULL;
1651
1652   // If the user set the address of the text segment, that may not be
1653   // compatible with putting the segment headers and file headers into
1654   // that segment.
1655   if (parameters->options().user_set_Ttext())
1656     load_seg = NULL;
1657
1658   gold_assert(phdr_seg == NULL
1659               || load_seg != NULL
1660               || this->script_options_->saw_sections_clause());
1661
1662   // If the address of the load segment we found has been set by
1663   // --section-start rather than by a script, then adjust the VMA and
1664   // LMA downward if possible to include the file and section headers.
1665   uint64_t header_gap = 0;
1666   if (load_seg != NULL
1667       && load_seg->are_addresses_set()
1668       && !this->script_options_->saw_sections_clause()
1669       && !parameters->options().relocatable())
1670     {
1671       file_header->finalize_data_size();
1672       segment_headers->finalize_data_size();
1673       size_t sizeof_headers = (file_header->data_size()
1674                                + segment_headers->data_size());
1675       const uint64_t abi_pagesize = target->abi_pagesize();
1676       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
1677       hdr_paddr &= ~(abi_pagesize - 1);
1678       uint64_t subtract = load_seg->paddr() - hdr_paddr;
1679       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
1680         load_seg = NULL;
1681       else
1682         {
1683           load_seg->set_addresses(load_seg->vaddr() - subtract,
1684                                   load_seg->paddr() - subtract);
1685           header_gap = subtract - sizeof_headers;
1686         }
1687     }
1688
1689   // Lay out the segment headers.
1690   if (!parameters->options().relocatable())
1691     {
1692       gold_assert(segment_headers != NULL);
1693       if (header_gap != 0 && load_seg != NULL)
1694         {
1695           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
1696           load_seg->add_initial_output_data(z);
1697         }
1698       if (load_seg != NULL)
1699         load_seg->add_initial_output_data(segment_headers);
1700       if (phdr_seg != NULL)
1701         phdr_seg->add_initial_output_data(segment_headers);
1702     }
1703
1704   // Lay out the file header.
1705   if (load_seg != NULL)
1706     load_seg->add_initial_output_data(file_header);
1707
1708   if (this->script_options_->saw_phdrs_clause()
1709       && !parameters->options().relocatable())
1710     {
1711       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1712       // clause in a linker script.
1713       Script_sections* ss = this->script_options_->script_sections();
1714       ss->put_headers_in_phdrs(file_header, segment_headers);
1715     }
1716
1717   // We set the output section indexes in set_segment_offsets and
1718   // set_section_indexes.
1719   *pshndx = 1;
1720
1721   // Set the file offsets of all the segments, and all the sections
1722   // they contain.
1723   off_t off;
1724   if (!parameters->options().relocatable())
1725     off = this->set_segment_offsets(target, load_seg, pshndx);
1726   else
1727     off = this->set_relocatable_section_offsets(file_header, pshndx);
1728
1729    // Verify that the dummy relaxation does not change anything.
1730   if (is_debugging_enabled(DEBUG_RELAXATION))
1731     {
1732       if (pass == 0)
1733         this->relaxation_debug_check_->read_sections(this->section_list_);
1734       else
1735         this->relaxation_debug_check_->verify_sections(this->section_list_);
1736     }
1737
1738   *pload_seg = load_seg;
1739   return off;
1740 }
1741
1742 // Search the list of patterns and find the postion of the given section
1743 // name in the output section.  If the section name matches a glob
1744 // pattern and a non-glob name, then the non-glob position takes
1745 // precedence.  Return 0 if no match is found.
1746
1747 unsigned int
1748 Layout::find_section_order_index(const std::string& section_name)
1749 {
1750   Unordered_map<std::string, unsigned int>::iterator map_it;
1751   map_it = this->input_section_position_.find(section_name);
1752   if (map_it != this->input_section_position_.end())
1753     return map_it->second;
1754
1755   // Absolute match failed.  Linear search the glob patterns.
1756   std::vector<std::string>::iterator it;
1757   for (it = this->input_section_glob_.begin();
1758        it != this->input_section_glob_.end();
1759        ++it)
1760     {
1761        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
1762          {
1763            map_it = this->input_section_position_.find(*it);
1764            gold_assert(map_it != this->input_section_position_.end());
1765            return map_it->second;
1766          }
1767     }
1768   return 0;
1769 }
1770
1771 // Read the sequence of input sections from the file specified with
1772 // --section-ordering-file.
1773
1774 void
1775 Layout::read_layout_from_file()
1776 {
1777   const char* filename = parameters->options().section_ordering_file();
1778   std::ifstream in;
1779   std::string line;
1780
1781   in.open(filename);
1782   if (!in)
1783     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
1784                filename, strerror(errno));
1785
1786   std::getline(in, line);   // this chops off the trailing \n, if any
1787   unsigned int position = 1;
1788
1789   while (in)
1790     {
1791       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
1792         line.resize(line.length() - 1);
1793       // Ignore comments, beginning with '#'
1794       if (line[0] == '#')
1795         {
1796           std::getline(in, line);
1797           continue;
1798         }
1799       this->input_section_position_[line] = position;
1800       // Store all glob patterns in a vector.
1801       if (is_wildcard_string(line.c_str()))
1802         this->input_section_glob_.push_back(line);
1803       position++;
1804       std::getline(in, line);
1805     }
1806 }
1807
1808 // Finalize the layout.  When this is called, we have created all the
1809 // output sections and all the output segments which are based on
1810 // input sections.  We have several things to do, and we have to do
1811 // them in the right order, so that we get the right results correctly
1812 // and efficiently.
1813
1814 // 1) Finalize the list of output segments and create the segment
1815 // table header.
1816
1817 // 2) Finalize the dynamic symbol table and associated sections.
1818
1819 // 3) Determine the final file offset of all the output segments.
1820
1821 // 4) Determine the final file offset of all the SHF_ALLOC output
1822 // sections.
1823
1824 // 5) Create the symbol table sections and the section name table
1825 // section.
1826
1827 // 6) Finalize the symbol table: set symbol values to their final
1828 // value and make a final determination of which symbols are going
1829 // into the output symbol table.
1830
1831 // 7) Create the section table header.
1832
1833 // 8) Determine the final file offset of all the output sections which
1834 // are not SHF_ALLOC, including the section table header.
1835
1836 // 9) Finalize the ELF file header.
1837
1838 // This function returns the size of the output file.
1839
1840 off_t
1841 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
1842                  Target* target, const Task* task)
1843 {
1844   target->finalize_sections(this, input_objects, symtab);
1845
1846   this->count_local_symbols(task, input_objects);
1847
1848   this->link_stabs_sections();
1849
1850   Output_segment* phdr_seg = NULL;
1851   if (!parameters->options().relocatable() && !parameters->doing_static_link())
1852     {
1853       // There was a dynamic object in the link.  We need to create
1854       // some information for the dynamic linker.
1855
1856       // Create the PT_PHDR segment which will hold the program
1857       // headers.
1858       if (!this->script_options_->saw_phdrs_clause())
1859         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
1860
1861       // Create the dynamic symbol table, including the hash table.
1862       Output_section* dynstr;
1863       std::vector<Symbol*> dynamic_symbols;
1864       unsigned int local_dynamic_count;
1865       Versions versions(*this->script_options()->version_script_info(),
1866                         &this->dynpool_);
1867       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
1868                                   &local_dynamic_count, &dynamic_symbols,
1869                                   &versions);
1870
1871       // Create the .interp section to hold the name of the
1872       // interpreter, and put it in a PT_INTERP segment.
1873       if (!parameters->options().shared())
1874         this->create_interp(target);
1875
1876       // Finish the .dynamic section to hold the dynamic data, and put
1877       // it in a PT_DYNAMIC segment.
1878       this->finish_dynamic_section(input_objects, symtab);
1879
1880       // We should have added everything we need to the dynamic string
1881       // table.
1882       this->dynpool_.set_string_offsets();
1883
1884       // Create the version sections.  We can't do this until the
1885       // dynamic string table is complete.
1886       this->create_version_sections(&versions, symtab, local_dynamic_count,
1887                                     dynamic_symbols, dynstr);
1888
1889       // Set the size of the _DYNAMIC symbol.  We can't do this until
1890       // after we call create_version_sections.
1891       this->set_dynamic_symbol_size(symtab);
1892     }
1893
1894   // Create segment headers.
1895   Output_segment_headers* segment_headers =
1896     (parameters->options().relocatable()
1897      ? NULL
1898      : new Output_segment_headers(this->segment_list_));
1899
1900   // Lay out the file header.
1901   Output_file_header* file_header
1902     = new Output_file_header(target, symtab, segment_headers,
1903                              parameters->options().entry());
1904
1905   this->special_output_list_.push_back(file_header);
1906   if (segment_headers != NULL)
1907     this->special_output_list_.push_back(segment_headers);
1908
1909   // Find approriate places for orphan output sections if we are using
1910   // a linker script.
1911   if (this->script_options_->saw_sections_clause())
1912     this->place_orphan_sections_in_script();
1913
1914   Output_segment* load_seg;
1915   off_t off;
1916   unsigned int shndx;
1917   int pass = 0;
1918
1919   // Take a snapshot of the section layout as needed.
1920   if (target->may_relax())
1921     this->prepare_for_relaxation();
1922
1923   // Run the relaxation loop to lay out sections.
1924   do
1925     {
1926       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
1927                                        phdr_seg, segment_headers, file_header,
1928                                        &shndx);
1929       pass++;
1930     }
1931   while (target->may_relax()
1932          && target->relax(pass, input_objects, symtab, this));
1933
1934   // Set the file offsets of all the non-data sections we've seen so
1935   // far which don't have to wait for the input sections.  We need
1936   // this in order to finalize local symbols in non-allocated
1937   // sections.
1938   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1939
1940   // Set the section indexes of all unallocated sections seen so far,
1941   // in case any of them are somehow referenced by a symbol.
1942   shndx = this->set_section_indexes(shndx);
1943
1944   // Create the symbol table sections.
1945   this->create_symtab_sections(input_objects, symtab, shndx, &off);
1946   if (!parameters->doing_static_link())
1947     this->assign_local_dynsym_offsets(input_objects);
1948
1949   // Process any symbol assignments from a linker script.  This must
1950   // be called after the symbol table has been finalized.
1951   this->script_options_->finalize_symbols(symtab, this);
1952
1953   // Create the incremental inputs sections.
1954   if (this->incremental_inputs_)
1955     {
1956       this->incremental_inputs_->finalize();
1957       this->create_incremental_info_sections(symtab);
1958     }
1959
1960   // Create the .shstrtab section.
1961   Output_section* shstrtab_section = this->create_shstrtab();
1962
1963   // Set the file offsets of the rest of the non-data sections which
1964   // don't have to wait for the input sections.
1965   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1966
1967   // Now that all sections have been created, set the section indexes
1968   // for any sections which haven't been done yet.
1969   shndx = this->set_section_indexes(shndx);
1970
1971   // Create the section table header.
1972   this->create_shdrs(shstrtab_section, &off);
1973
1974   // If there are no sections which require postprocessing, we can
1975   // handle the section names now, and avoid a resize later.
1976   if (!this->any_postprocessing_sections_)
1977     {
1978       off = this->set_section_offsets(off,
1979                                       POSTPROCESSING_SECTIONS_PASS);
1980       off =
1981           this->set_section_offsets(off,
1982                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1983     }
1984
1985   file_header->set_section_info(this->section_headers_, shstrtab_section);
1986
1987   // Now we know exactly where everything goes in the output file
1988   // (except for non-allocated sections which require postprocessing).
1989   Output_data::layout_complete();
1990
1991   this->output_file_size_ = off;
1992
1993   return off;
1994 }
1995
1996 // Create a note header following the format defined in the ELF ABI.
1997 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
1998 // of the section to create, DESCSZ is the size of the descriptor.
1999 // ALLOCATE is true if the section should be allocated in memory.
2000 // This returns the new note section.  It sets *TRAILING_PADDING to
2001 // the number of trailing zero bytes required.
2002
2003 Output_section*
2004 Layout::create_note(const char* name, int note_type,
2005                     const char* section_name, size_t descsz,
2006                     bool allocate, size_t* trailing_padding)
2007 {
2008   // Authorities all agree that the values in a .note field should
2009   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
2010   // they differ on what the alignment is for 64-bit binaries.
2011   // The GABI says unambiguously they take 8-byte alignment:
2012   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2013   // Other documentation says alignment should always be 4 bytes:
2014   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2015   // GNU ld and GNU readelf both support the latter (at least as of
2016   // version 2.16.91), and glibc always generates the latter for
2017   // .note.ABI-tag (as of version 1.6), so that's the one we go with
2018   // here.
2019 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
2020   const int size = parameters->target().get_size();
2021 #else
2022   const int size = 32;
2023 #endif
2024
2025   // The contents of the .note section.
2026   size_t namesz = strlen(name) + 1;
2027   size_t aligned_namesz = align_address(namesz, size / 8);
2028   size_t aligned_descsz = align_address(descsz, size / 8);
2029
2030   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2031
2032   unsigned char* buffer = new unsigned char[notehdrsz];
2033   memset(buffer, 0, notehdrsz);
2034
2035   bool is_big_endian = parameters->target().is_big_endian();
2036
2037   if (size == 32)
2038     {
2039       if (!is_big_endian)
2040         {
2041           elfcpp::Swap<32, false>::writeval(buffer, namesz);
2042           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2043           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2044         }
2045       else
2046         {
2047           elfcpp::Swap<32, true>::writeval(buffer, namesz);
2048           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2049           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2050         }
2051     }
2052   else if (size == 64)
2053     {
2054       if (!is_big_endian)
2055         {
2056           elfcpp::Swap<64, false>::writeval(buffer, namesz);
2057           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2058           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2059         }
2060       else
2061         {
2062           elfcpp::Swap<64, true>::writeval(buffer, namesz);
2063           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2064           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2065         }
2066     }
2067   else
2068     gold_unreachable();
2069
2070   memcpy(buffer + 3 * (size / 8), name, namesz);
2071
2072   elfcpp::Elf_Xword flags = 0;
2073   Output_section_order order = ORDER_INVALID;
2074   if (allocate)
2075     {
2076       flags = elfcpp::SHF_ALLOC;
2077       order = ORDER_RO_NOTE;
2078     }
2079   Output_section* os = this->choose_output_section(NULL, section_name,
2080                                                    elfcpp::SHT_NOTE,
2081                                                    flags, false, order, false);
2082   if (os == NULL)
2083     return NULL;
2084
2085   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2086                                                            size / 8,
2087                                                            "** note header");
2088   os->add_output_section_data(posd);
2089
2090   *trailing_padding = aligned_descsz - descsz;
2091
2092   return os;
2093 }
2094
2095 // For an executable or shared library, create a note to record the
2096 // version of gold used to create the binary.
2097
2098 void
2099 Layout::create_gold_note()
2100 {
2101   if (parameters->options().relocatable())
2102     return;
2103
2104   std::string desc = std::string("gold ") + gold::get_version_string();
2105
2106   size_t trailing_padding;
2107   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2108                                          ".note.gnu.gold-version", desc.size(),
2109                                          false, &trailing_padding);
2110   if (os == NULL)
2111     return;
2112
2113   Output_section_data* posd = new Output_data_const(desc, 4);
2114   os->add_output_section_data(posd);
2115
2116   if (trailing_padding > 0)
2117     {
2118       posd = new Output_data_zero_fill(trailing_padding, 0);
2119       os->add_output_section_data(posd);
2120     }
2121 }
2122
2123 // Record whether the stack should be executable.  This can be set
2124 // from the command line using the -z execstack or -z noexecstack
2125 // options.  Otherwise, if any input file has a .note.GNU-stack
2126 // section with the SHF_EXECINSTR flag set, the stack should be
2127 // executable.  Otherwise, if at least one input file a
2128 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2129 // section, we use the target default for whether the stack should be
2130 // executable.  Otherwise, we don't generate a stack note.  When
2131 // generating a object file, we create a .note.GNU-stack section with
2132 // the appropriate marking.  When generating an executable or shared
2133 // library, we create a PT_GNU_STACK segment.
2134
2135 void
2136 Layout::create_executable_stack_info()
2137 {
2138   bool is_stack_executable;
2139   if (parameters->options().is_execstack_set())
2140     is_stack_executable = parameters->options().is_stack_executable();
2141   else if (!this->input_with_gnu_stack_note_)
2142     return;
2143   else
2144     {
2145       if (this->input_requires_executable_stack_)
2146         is_stack_executable = true;
2147       else if (this->input_without_gnu_stack_note_)
2148         is_stack_executable =
2149           parameters->target().is_default_stack_executable();
2150       else
2151         is_stack_executable = false;
2152     }
2153
2154   if (parameters->options().relocatable())
2155     {
2156       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2157       elfcpp::Elf_Xword flags = 0;
2158       if (is_stack_executable)
2159         flags |= elfcpp::SHF_EXECINSTR;
2160       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2161                                 ORDER_INVALID, false);
2162     }
2163   else
2164     {
2165       if (this->script_options_->saw_phdrs_clause())
2166         return;
2167       int flags = elfcpp::PF_R | elfcpp::PF_W;
2168       if (is_stack_executable)
2169         flags |= elfcpp::PF_X;
2170       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2171     }
2172 }
2173
2174 // If --build-id was used, set up the build ID note.
2175
2176 void
2177 Layout::create_build_id()
2178 {
2179   if (!parameters->options().user_set_build_id())
2180     return;
2181
2182   const char* style = parameters->options().build_id();
2183   if (strcmp(style, "none") == 0)
2184     return;
2185
2186   // Set DESCSZ to the size of the note descriptor.  When possible,
2187   // set DESC to the note descriptor contents.
2188   size_t descsz;
2189   std::string desc;
2190   if (strcmp(style, "md5") == 0)
2191     descsz = 128 / 8;
2192   else if (strcmp(style, "sha1") == 0)
2193     descsz = 160 / 8;
2194   else if (strcmp(style, "uuid") == 0)
2195     {
2196       const size_t uuidsz = 128 / 8;
2197
2198       char buffer[uuidsz];
2199       memset(buffer, 0, uuidsz);
2200
2201       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2202       if (descriptor < 0)
2203         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2204                    strerror(errno));
2205       else
2206         {
2207           ssize_t got = ::read(descriptor, buffer, uuidsz);
2208           release_descriptor(descriptor, true);
2209           if (got < 0)
2210             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2211           else if (static_cast<size_t>(got) != uuidsz)
2212             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2213                        uuidsz, got);
2214         }
2215
2216       desc.assign(buffer, uuidsz);
2217       descsz = uuidsz;
2218     }
2219   else if (strncmp(style, "0x", 2) == 0)
2220     {
2221       hex_init();
2222       const char* p = style + 2;
2223       while (*p != '\0')
2224         {
2225           if (hex_p(p[0]) && hex_p(p[1]))
2226             {
2227               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2228               desc += c;
2229               p += 2;
2230             }
2231           else if (*p == '-' || *p == ':')
2232             ++p;
2233           else
2234             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2235                        style);
2236         }
2237       descsz = desc.size();
2238     }
2239   else
2240     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2241
2242   // Create the note.
2243   size_t trailing_padding;
2244   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2245                                          ".note.gnu.build-id", descsz, true,
2246                                          &trailing_padding);
2247   if (os == NULL)
2248     return;
2249
2250   if (!desc.empty())
2251     {
2252       // We know the value already, so we fill it in now.
2253       gold_assert(desc.size() == descsz);
2254
2255       Output_section_data* posd = new Output_data_const(desc, 4);
2256       os->add_output_section_data(posd);
2257
2258       if (trailing_padding != 0)
2259         {
2260           posd = new Output_data_zero_fill(trailing_padding, 0);
2261           os->add_output_section_data(posd);
2262         }
2263     }
2264   else
2265     {
2266       // We need to compute a checksum after we have completed the
2267       // link.
2268       gold_assert(trailing_padding == 0);
2269       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2270       os->add_output_section_data(this->build_id_note_);
2271     }
2272 }
2273
2274 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2275 // field of the former should point to the latter.  I'm not sure who
2276 // started this, but the GNU linker does it, and some tools depend
2277 // upon it.
2278
2279 void
2280 Layout::link_stabs_sections()
2281 {
2282   if (!this->have_stabstr_section_)
2283     return;
2284
2285   for (Section_list::iterator p = this->section_list_.begin();
2286        p != this->section_list_.end();
2287        ++p)
2288     {
2289       if ((*p)->type() != elfcpp::SHT_STRTAB)
2290         continue;
2291
2292       const char* name = (*p)->name();
2293       if (strncmp(name, ".stab", 5) != 0)
2294         continue;
2295
2296       size_t len = strlen(name);
2297       if (strcmp(name + len - 3, "str") != 0)
2298         continue;
2299
2300       std::string stab_name(name, len - 3);
2301       Output_section* stab_sec;
2302       stab_sec = this->find_output_section(stab_name.c_str());
2303       if (stab_sec != NULL)
2304         stab_sec->set_link_section(*p);
2305     }
2306 }
2307
2308 // Create .gnu_incremental_inputs and related sections needed
2309 // for the next run of incremental linking to check what has changed.
2310
2311 void
2312 Layout::create_incremental_info_sections(Symbol_table* symtab)
2313 {
2314   Incremental_inputs* incr = this->incremental_inputs_;
2315
2316   gold_assert(incr != NULL);
2317
2318   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2319   incr->create_data_sections(symtab);
2320
2321   // Add the .gnu_incremental_inputs section.
2322   const char* incremental_inputs_name =
2323     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2324   Output_section* incremental_inputs_os =
2325     this->make_output_section(incremental_inputs_name,
2326                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2327                               ORDER_INVALID, false);
2328   incremental_inputs_os->add_output_section_data(incr->inputs_section());
2329
2330   // Add the .gnu_incremental_symtab section.
2331   const char* incremental_symtab_name =
2332     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2333   Output_section* incremental_symtab_os =
2334     this->make_output_section(incremental_symtab_name,
2335                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2336                               ORDER_INVALID, false);
2337   incremental_symtab_os->add_output_section_data(incr->symtab_section());
2338   incremental_symtab_os->set_entsize(4);
2339
2340   // Add the .gnu_incremental_relocs section.
2341   const char* incremental_relocs_name =
2342     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2343   Output_section* incremental_relocs_os =
2344     this->make_output_section(incremental_relocs_name,
2345                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2346                               ORDER_INVALID, false);
2347   incremental_relocs_os->add_output_section_data(incr->relocs_section());
2348   incremental_relocs_os->set_entsize(incr->relocs_entsize());
2349
2350   // Add the .gnu_incremental_got_plt section.
2351   const char* incremental_got_plt_name =
2352     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2353   Output_section* incremental_got_plt_os =
2354     this->make_output_section(incremental_got_plt_name,
2355                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2356                               ORDER_INVALID, false);
2357   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2358
2359   // Add the .gnu_incremental_strtab section.
2360   const char* incremental_strtab_name =
2361     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2362   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2363                                                         elfcpp::SHT_STRTAB, 0,
2364                                                         ORDER_INVALID, false);
2365   Output_data_strtab* strtab_data =
2366       new Output_data_strtab(incr->get_stringpool());
2367   incremental_strtab_os->add_output_section_data(strtab_data);
2368
2369   incremental_inputs_os->set_after_input_sections();
2370   incremental_symtab_os->set_after_input_sections();
2371   incremental_relocs_os->set_after_input_sections();
2372   incremental_got_plt_os->set_after_input_sections();
2373
2374   incremental_inputs_os->set_link_section(incremental_strtab_os);
2375   incremental_symtab_os->set_link_section(incremental_inputs_os);
2376   incremental_relocs_os->set_link_section(incremental_inputs_os);
2377   incremental_got_plt_os->set_link_section(incremental_inputs_os);
2378 }
2379
2380 // Return whether SEG1 should be before SEG2 in the output file.  This
2381 // is based entirely on the segment type and flags.  When this is
2382 // called the segment addresses has normally not yet been set.
2383
2384 bool
2385 Layout::segment_precedes(const Output_segment* seg1,
2386                          const Output_segment* seg2)
2387 {
2388   elfcpp::Elf_Word type1 = seg1->type();
2389   elfcpp::Elf_Word type2 = seg2->type();
2390
2391   // The single PT_PHDR segment is required to precede any loadable
2392   // segment.  We simply make it always first.
2393   if (type1 == elfcpp::PT_PHDR)
2394     {
2395       gold_assert(type2 != elfcpp::PT_PHDR);
2396       return true;
2397     }
2398   if (type2 == elfcpp::PT_PHDR)
2399     return false;
2400
2401   // The single PT_INTERP segment is required to precede any loadable
2402   // segment.  We simply make it always second.
2403   if (type1 == elfcpp::PT_INTERP)
2404     {
2405       gold_assert(type2 != elfcpp::PT_INTERP);
2406       return true;
2407     }
2408   if (type2 == elfcpp::PT_INTERP)
2409     return false;
2410
2411   // We then put PT_LOAD segments before any other segments.
2412   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2413     return true;
2414   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2415     return false;
2416
2417   // We put the PT_TLS segment last except for the PT_GNU_RELRO
2418   // segment, because that is where the dynamic linker expects to find
2419   // it (this is just for efficiency; other positions would also work
2420   // correctly).
2421   if (type1 == elfcpp::PT_TLS
2422       && type2 != elfcpp::PT_TLS
2423       && type2 != elfcpp::PT_GNU_RELRO)
2424     return false;
2425   if (type2 == elfcpp::PT_TLS
2426       && type1 != elfcpp::PT_TLS
2427       && type1 != elfcpp::PT_GNU_RELRO)
2428     return true;
2429
2430   // We put the PT_GNU_RELRO segment last, because that is where the
2431   // dynamic linker expects to find it (as with PT_TLS, this is just
2432   // for efficiency).
2433   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2434     return false;
2435   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2436     return true;
2437
2438   const elfcpp::Elf_Word flags1 = seg1->flags();
2439   const elfcpp::Elf_Word flags2 = seg2->flags();
2440
2441   // The order of non-PT_LOAD segments is unimportant.  We simply sort
2442   // by the numeric segment type and flags values.  There should not
2443   // be more than one segment with the same type and flags.
2444   if (type1 != elfcpp::PT_LOAD)
2445     {
2446       if (type1 != type2)
2447         return type1 < type2;
2448       gold_assert(flags1 != flags2);
2449       return flags1 < flags2;
2450     }
2451
2452   // If the addresses are set already, sort by load address.
2453   if (seg1->are_addresses_set())
2454     {
2455       if (!seg2->are_addresses_set())
2456         return true;
2457
2458       unsigned int section_count1 = seg1->output_section_count();
2459       unsigned int section_count2 = seg2->output_section_count();
2460       if (section_count1 == 0 && section_count2 > 0)
2461         return true;
2462       if (section_count1 > 0 && section_count2 == 0)
2463         return false;
2464
2465       uint64_t paddr1 = (seg1->are_addresses_set()
2466                          ? seg1->paddr()
2467                          : seg1->first_section_load_address());
2468       uint64_t paddr2 = (seg2->are_addresses_set()
2469                          ? seg2->paddr()
2470                          : seg2->first_section_load_address());
2471
2472       if (paddr1 != paddr2)
2473         return paddr1 < paddr2;
2474     }
2475   else if (seg2->are_addresses_set())
2476     return false;
2477
2478   // A segment which holds large data comes after a segment which does
2479   // not hold large data.
2480   if (seg1->is_large_data_segment())
2481     {
2482       if (!seg2->is_large_data_segment())
2483         return false;
2484     }
2485   else if (seg2->is_large_data_segment())
2486     return true;
2487
2488   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
2489   // segments come before writable segments.  Then writable segments
2490   // with data come before writable segments without data.  Then
2491   // executable segments come before non-executable segments.  Then
2492   // the unlikely case of a non-readable segment comes before the
2493   // normal case of a readable segment.  If there are multiple
2494   // segments with the same type and flags, we require that the
2495   // address be set, and we sort by virtual address and then physical
2496   // address.
2497   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2498     return (flags1 & elfcpp::PF_W) == 0;
2499   if ((flags1 & elfcpp::PF_W) != 0
2500       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2501     return seg1->has_any_data_sections();
2502   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2503     return (flags1 & elfcpp::PF_X) != 0;
2504   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2505     return (flags1 & elfcpp::PF_R) == 0;
2506
2507   // We shouldn't get here--we shouldn't create segments which we
2508   // can't distinguish.
2509   gold_unreachable();
2510 }
2511
2512 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2513
2514 static off_t
2515 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2516 {
2517   uint64_t unsigned_off = off;
2518   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2519                           | (addr & (abi_pagesize - 1)));
2520   if (aligned_off < unsigned_off)
2521     aligned_off += abi_pagesize;
2522   return aligned_off;
2523 }
2524
2525 // Set the file offsets of all the segments, and all the sections they
2526 // contain.  They have all been created.  LOAD_SEG must be be laid out
2527 // first.  Return the offset of the data to follow.
2528
2529 off_t
2530 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
2531                             unsigned int* pshndx)
2532 {
2533   // Sort them into the final order.
2534   std::sort(this->segment_list_.begin(), this->segment_list_.end(),
2535             Layout::Compare_segments());
2536
2537   // Find the PT_LOAD segments, and set their addresses and offsets
2538   // and their section's addresses and offsets.
2539   uint64_t addr;
2540   if (parameters->options().user_set_Ttext())
2541     addr = parameters->options().Ttext();
2542   else if (parameters->options().output_is_position_independent())
2543     addr = 0;
2544   else
2545     addr = target->default_text_segment_address();
2546   off_t off = 0;
2547
2548   // If LOAD_SEG is NULL, then the file header and segment headers
2549   // will not be loadable.  But they still need to be at offset 0 in
2550   // the file.  Set their offsets now.
2551   if (load_seg == NULL)
2552     {
2553       for (Data_list::iterator p = this->special_output_list_.begin();
2554            p != this->special_output_list_.end();
2555            ++p)
2556         {
2557           off = align_address(off, (*p)->addralign());
2558           (*p)->set_address_and_file_offset(0, off);
2559           off += (*p)->data_size();
2560         }
2561     }
2562
2563   unsigned int increase_relro = this->increase_relro_;
2564   if (this->script_options_->saw_sections_clause())
2565     increase_relro = 0;
2566
2567   const bool check_sections = parameters->options().check_sections();
2568   Output_segment* last_load_segment = NULL;
2569
2570   bool was_readonly = false;
2571   for (Segment_list::iterator p = this->segment_list_.begin();
2572        p != this->segment_list_.end();
2573        ++p)
2574     {
2575       if ((*p)->type() == elfcpp::PT_LOAD)
2576         {
2577           if (load_seg != NULL && load_seg != *p)
2578             gold_unreachable();
2579           load_seg = NULL;
2580
2581           bool are_addresses_set = (*p)->are_addresses_set();
2582           if (are_addresses_set)
2583             {
2584               // When it comes to setting file offsets, we care about
2585               // the physical address.
2586               addr = (*p)->paddr();
2587             }
2588           else if (parameters->options().user_set_Tdata()
2589                    && ((*p)->flags() & elfcpp::PF_W) != 0
2590                    && (!parameters->options().user_set_Tbss()
2591                        || (*p)->has_any_data_sections()))
2592             {
2593               addr = parameters->options().Tdata();
2594               are_addresses_set = true;
2595             }
2596           else if (parameters->options().user_set_Tbss()
2597                    && ((*p)->flags() & elfcpp::PF_W) != 0
2598                    && !(*p)->has_any_data_sections())
2599             {
2600               addr = parameters->options().Tbss();
2601               are_addresses_set = true;
2602             }
2603
2604           uint64_t orig_addr = addr;
2605           uint64_t orig_off = off;
2606
2607           uint64_t aligned_addr = 0;
2608           uint64_t abi_pagesize = target->abi_pagesize();
2609           uint64_t common_pagesize = target->common_pagesize();
2610
2611           if (!parameters->options().nmagic()
2612               && !parameters->options().omagic())
2613             (*p)->set_minimum_p_align(common_pagesize);
2614
2615           if (!are_addresses_set)
2616             {
2617               // If the last segment was readonly, and this one is
2618               // not, then skip the address forward one page,
2619               // maintaining the same position within the page.  This
2620               // lets us store both segments overlapping on a single
2621               // page in the file, but the loader will put them on
2622               // different pages in memory.
2623
2624               addr = align_address(addr, (*p)->maximum_alignment());
2625               aligned_addr = addr;
2626
2627               if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
2628                 {
2629                   if ((addr & (abi_pagesize - 1)) != 0)
2630                     addr = addr + abi_pagesize;
2631                 }
2632
2633               off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2634             }
2635
2636           if (!parameters->options().nmagic()
2637               && !parameters->options().omagic())
2638             off = align_file_offset(off, addr, abi_pagesize);
2639           else if (load_seg == NULL)
2640             {
2641               // This is -N or -n with a section script which prevents
2642               // us from using a load segment.  We need to ensure that
2643               // the file offset is aligned to the alignment of the
2644               // segment.  This is because the linker script
2645               // implicitly assumed a zero offset.  If we don't align
2646               // here, then the alignment of the sections in the
2647               // linker script may not match the alignment of the
2648               // sections in the set_section_addresses call below,
2649               // causing an error about dot moving backward.
2650               off = align_address(off, (*p)->maximum_alignment());
2651             }
2652
2653           unsigned int shndx_hold = *pshndx;
2654           uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
2655                                                           increase_relro,
2656                                                           &off, pshndx);
2657
2658           // Now that we know the size of this segment, we may be able
2659           // to save a page in memory, at the cost of wasting some
2660           // file space, by instead aligning to the start of a new
2661           // page.  Here we use the real machine page size rather than
2662           // the ABI mandated page size.
2663
2664           if (!are_addresses_set && aligned_addr != addr)
2665             {
2666               uint64_t first_off = (common_pagesize
2667                                     - (aligned_addr
2668                                        & (common_pagesize - 1)));
2669               uint64_t last_off = new_addr & (common_pagesize - 1);
2670               if (first_off > 0
2671                   && last_off > 0
2672                   && ((aligned_addr & ~ (common_pagesize - 1))
2673                       != (new_addr & ~ (common_pagesize - 1)))
2674                   && first_off + last_off <= common_pagesize)
2675                 {
2676                   *pshndx = shndx_hold;
2677                   addr = align_address(aligned_addr, common_pagesize);
2678                   addr = align_address(addr, (*p)->maximum_alignment());
2679                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2680                   off = align_file_offset(off, addr, abi_pagesize);
2681                   new_addr = (*p)->set_section_addresses(this, true, addr,
2682                                                          increase_relro,
2683                                                          &off, pshndx);
2684                 }
2685             }
2686
2687           addr = new_addr;
2688
2689           if (((*p)->flags() & elfcpp::PF_W) == 0)
2690             was_readonly = true;
2691
2692           // Implement --check-sections.  We know that the segments
2693           // are sorted by LMA.
2694           if (check_sections && last_load_segment != NULL)
2695             {
2696               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
2697               if (last_load_segment->paddr() + last_load_segment->memsz()
2698                   > (*p)->paddr())
2699                 {
2700                   unsigned long long lb1 = last_load_segment->paddr();
2701                   unsigned long long le1 = lb1 + last_load_segment->memsz();
2702                   unsigned long long lb2 = (*p)->paddr();
2703                   unsigned long long le2 = lb2 + (*p)->memsz();
2704                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2705                                "[0x%llx -> 0x%llx]"),
2706                              lb1, le1, lb2, le2);
2707                 }
2708             }
2709           last_load_segment = *p;
2710         }
2711     }
2712
2713   // Handle the non-PT_LOAD segments, setting their offsets from their
2714   // section's offsets.
2715   for (Segment_list::iterator p = this->segment_list_.begin();
2716        p != this->segment_list_.end();
2717        ++p)
2718     {
2719       if ((*p)->type() != elfcpp::PT_LOAD)
2720         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
2721                          ? increase_relro
2722                          : 0);
2723     }
2724
2725   // Set the TLS offsets for each section in the PT_TLS segment.
2726   if (this->tls_segment_ != NULL)
2727     this->tls_segment_->set_tls_offsets();
2728
2729   return off;
2730 }
2731
2732 // Set the offsets of all the allocated sections when doing a
2733 // relocatable link.  This does the same jobs as set_segment_offsets,
2734 // only for a relocatable link.
2735
2736 off_t
2737 Layout::set_relocatable_section_offsets(Output_data* file_header,
2738                                         unsigned int* pshndx)
2739 {
2740   off_t off = 0;
2741
2742   file_header->set_address_and_file_offset(0, 0);
2743   off += file_header->data_size();
2744
2745   for (Section_list::iterator p = this->section_list_.begin();
2746        p != this->section_list_.end();
2747        ++p)
2748     {
2749       // We skip unallocated sections here, except that group sections
2750       // have to come first.
2751       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
2752           && (*p)->type() != elfcpp::SHT_GROUP)
2753         continue;
2754
2755       off = align_address(off, (*p)->addralign());
2756
2757       // The linker script might have set the address.
2758       if (!(*p)->is_address_valid())
2759         (*p)->set_address(0);
2760       (*p)->set_file_offset(off);
2761       (*p)->finalize_data_size();
2762       off += (*p)->data_size();
2763
2764       (*p)->set_out_shndx(*pshndx);
2765       ++*pshndx;
2766     }
2767
2768   return off;
2769 }
2770
2771 // Set the file offset of all the sections not associated with a
2772 // segment.
2773
2774 off_t
2775 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
2776 {
2777   for (Section_list::iterator p = this->unattached_section_list_.begin();
2778        p != this->unattached_section_list_.end();
2779        ++p)
2780     {
2781       // The symtab section is handled in create_symtab_sections.
2782       if (*p == this->symtab_section_)
2783         continue;
2784
2785       // If we've already set the data size, don't set it again.
2786       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
2787         continue;
2788
2789       if (pass == BEFORE_INPUT_SECTIONS_PASS
2790           && (*p)->requires_postprocessing())
2791         {
2792           (*p)->create_postprocessing_buffer();
2793           this->any_postprocessing_sections_ = true;
2794         }
2795
2796       if (pass == BEFORE_INPUT_SECTIONS_PASS
2797           && (*p)->after_input_sections())
2798         continue;
2799       else if (pass == POSTPROCESSING_SECTIONS_PASS
2800                && (!(*p)->after_input_sections()
2801                    || (*p)->type() == elfcpp::SHT_STRTAB))
2802         continue;
2803       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
2804                && (!(*p)->after_input_sections()
2805                    || (*p)->type() != elfcpp::SHT_STRTAB))
2806         continue;
2807
2808       off = align_address(off, (*p)->addralign());
2809       (*p)->set_file_offset(off);
2810       (*p)->finalize_data_size();
2811       off += (*p)->data_size();
2812
2813       // At this point the name must be set.
2814       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
2815         this->namepool_.add((*p)->name(), false, NULL);
2816     }
2817   return off;
2818 }
2819
2820 // Set the section indexes of all the sections not associated with a
2821 // segment.
2822
2823 unsigned int
2824 Layout::set_section_indexes(unsigned int shndx)
2825 {
2826   for (Section_list::iterator p = this->unattached_section_list_.begin();
2827        p != this->unattached_section_list_.end();
2828        ++p)
2829     {
2830       if (!(*p)->has_out_shndx())
2831         {
2832           (*p)->set_out_shndx(shndx);
2833           ++shndx;
2834         }
2835     }
2836   return shndx;
2837 }
2838
2839 // Set the section addresses according to the linker script.  This is
2840 // only called when we see a SECTIONS clause.  This returns the
2841 // program segment which should hold the file header and segment
2842 // headers, if any.  It will return NULL if they should not be in a
2843 // segment.
2844
2845 Output_segment*
2846 Layout::set_section_addresses_from_script(Symbol_table* symtab)
2847 {
2848   Script_sections* ss = this->script_options_->script_sections();
2849   gold_assert(ss->saw_sections_clause());
2850   return this->script_options_->set_section_addresses(symtab, this);
2851 }
2852
2853 // Place the orphan sections in the linker script.
2854
2855 void
2856 Layout::place_orphan_sections_in_script()
2857 {
2858   Script_sections* ss = this->script_options_->script_sections();
2859   gold_assert(ss->saw_sections_clause());
2860
2861   // Place each orphaned output section in the script.
2862   for (Section_list::iterator p = this->section_list_.begin();
2863        p != this->section_list_.end();
2864        ++p)
2865     {
2866       if (!(*p)->found_in_sections_clause())
2867         ss->place_orphan(*p);
2868     }
2869 }
2870
2871 // Count the local symbols in the regular symbol table and the dynamic
2872 // symbol table, and build the respective string pools.
2873
2874 void
2875 Layout::count_local_symbols(const Task* task,
2876                             const Input_objects* input_objects)
2877 {
2878   // First, figure out an upper bound on the number of symbols we'll
2879   // be inserting into each pool.  This helps us create the pools with
2880   // the right size, to avoid unnecessary hashtable resizing.
2881   unsigned int symbol_count = 0;
2882   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2883        p != input_objects->relobj_end();
2884        ++p)
2885     symbol_count += (*p)->local_symbol_count();
2886
2887   // Go from "upper bound" to "estimate."  We overcount for two
2888   // reasons: we double-count symbols that occur in more than one
2889   // object file, and we count symbols that are dropped from the
2890   // output.  Add it all together and assume we overcount by 100%.
2891   symbol_count /= 2;
2892
2893   // We assume all symbols will go into both the sympool and dynpool.
2894   this->sympool_.reserve(symbol_count);
2895   this->dynpool_.reserve(symbol_count);
2896
2897   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2898        p != input_objects->relobj_end();
2899        ++p)
2900     {
2901       Task_lock_obj<Object> tlo(task, *p);
2902       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
2903     }
2904 }
2905
2906 // Create the symbol table sections.  Here we also set the final
2907 // values of the symbols.  At this point all the loadable sections are
2908 // fully laid out.  SHNUM is the number of sections so far.
2909
2910 void
2911 Layout::create_symtab_sections(const Input_objects* input_objects,
2912                                Symbol_table* symtab,
2913                                unsigned int shnum,
2914                                off_t* poff)
2915 {
2916   int symsize;
2917   unsigned int align;
2918   if (parameters->target().get_size() == 32)
2919     {
2920       symsize = elfcpp::Elf_sizes<32>::sym_size;
2921       align = 4;
2922     }
2923   else if (parameters->target().get_size() == 64)
2924     {
2925       symsize = elfcpp::Elf_sizes<64>::sym_size;
2926       align = 8;
2927     }
2928   else
2929     gold_unreachable();
2930
2931   off_t off = *poff;
2932   off = align_address(off, align);
2933   off_t startoff = off;
2934
2935   // Save space for the dummy symbol at the start of the section.  We
2936   // never bother to write this out--it will just be left as zero.
2937   off += symsize;
2938   unsigned int local_symbol_index = 1;
2939
2940   // Add STT_SECTION symbols for each Output section which needs one.
2941   for (Section_list::iterator p = this->section_list_.begin();
2942        p != this->section_list_.end();
2943        ++p)
2944     {
2945       if (!(*p)->needs_symtab_index())
2946         (*p)->set_symtab_index(-1U);
2947       else
2948         {
2949           (*p)->set_symtab_index(local_symbol_index);
2950           ++local_symbol_index;
2951           off += symsize;
2952         }
2953     }
2954
2955   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2956        p != input_objects->relobj_end();
2957        ++p)
2958     {
2959       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
2960                                                         off, symtab);
2961       off += (index - local_symbol_index) * symsize;
2962       local_symbol_index = index;
2963     }
2964
2965   unsigned int local_symcount = local_symbol_index;
2966   gold_assert(static_cast<off_t>(local_symcount * symsize) == off - startoff);
2967
2968   off_t dynoff;
2969   size_t dyn_global_index;
2970   size_t dyncount;
2971   if (this->dynsym_section_ == NULL)
2972     {
2973       dynoff = 0;
2974       dyn_global_index = 0;
2975       dyncount = 0;
2976     }
2977   else
2978     {
2979       dyn_global_index = this->dynsym_section_->info();
2980       off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
2981       dynoff = this->dynsym_section_->offset() + locsize;
2982       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
2983       gold_assert(static_cast<off_t>(dyncount * symsize)
2984                   == this->dynsym_section_->data_size() - locsize);
2985     }
2986
2987   off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
2988                          &this->sympool_, &local_symcount);
2989
2990   if (!parameters->options().strip_all())
2991     {
2992       this->sympool_.set_string_offsets();
2993
2994       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
2995       Output_section* osymtab = this->make_output_section(symtab_name,
2996                                                           elfcpp::SHT_SYMTAB,
2997                                                           0, ORDER_INVALID,
2998                                                           false);
2999       this->symtab_section_ = osymtab;
3000
3001       Output_section_data* pos = new Output_data_fixed_space(off - startoff,
3002                                                              align,
3003                                                              "** symtab");
3004       osymtab->add_output_section_data(pos);
3005
3006       // We generate a .symtab_shndx section if we have more than
3007       // SHN_LORESERVE sections.  Technically it is possible that we
3008       // don't need one, because it is possible that there are no
3009       // symbols in any of sections with indexes larger than
3010       // SHN_LORESERVE.  That is probably unusual, though, and it is
3011       // easier to always create one than to compute section indexes
3012       // twice (once here, once when writing out the symbols).
3013       if (shnum >= elfcpp::SHN_LORESERVE)
3014         {
3015           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3016                                                                false, NULL);
3017           Output_section* osymtab_xindex =
3018             this->make_output_section(symtab_xindex_name,
3019                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
3020                                       ORDER_INVALID, false);
3021
3022           size_t symcount = (off - startoff) / symsize;
3023           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3024
3025           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3026
3027           osymtab_xindex->set_link_section(osymtab);
3028           osymtab_xindex->set_addralign(4);
3029           osymtab_xindex->set_entsize(4);
3030
3031           osymtab_xindex->set_after_input_sections();
3032
3033           // This tells the driver code to wait until the symbol table
3034           // has written out before writing out the postprocessing
3035           // sections, including the .symtab_shndx section.
3036           this->any_postprocessing_sections_ = true;
3037         }
3038
3039       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3040       Output_section* ostrtab = this->make_output_section(strtab_name,
3041                                                           elfcpp::SHT_STRTAB,
3042                                                           0, ORDER_INVALID,
3043                                                           false);
3044
3045       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3046       ostrtab->add_output_section_data(pstr);
3047
3048       osymtab->set_file_offset(startoff);
3049       osymtab->finalize_data_size();
3050       osymtab->set_link_section(ostrtab);
3051       osymtab->set_info(local_symcount);
3052       osymtab->set_entsize(symsize);
3053
3054       *poff = off;
3055     }
3056 }
3057
3058 // Create the .shstrtab section, which holds the names of the
3059 // sections.  At the time this is called, we have created all the
3060 // output sections except .shstrtab itself.
3061
3062 Output_section*
3063 Layout::create_shstrtab()
3064 {
3065   // FIXME: We don't need to create a .shstrtab section if we are
3066   // stripping everything.
3067
3068   const char* name = this->namepool_.add(".shstrtab", false, NULL);
3069
3070   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3071                                                  ORDER_INVALID, false);
3072
3073   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3074     {
3075       // We can't write out this section until we've set all the
3076       // section names, and we don't set the names of compressed
3077       // output sections until relocations are complete.  FIXME: With
3078       // the current names we use, this is unnecessary.
3079       os->set_after_input_sections();
3080     }
3081
3082   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3083   os->add_output_section_data(posd);
3084
3085   return os;
3086 }
3087
3088 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
3089 // offset.
3090
3091 void
3092 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3093 {
3094   Output_section_headers* oshdrs;
3095   oshdrs = new Output_section_headers(this,
3096                                       &this->segment_list_,
3097                                       &this->section_list_,
3098                                       &this->unattached_section_list_,
3099                                       &this->namepool_,
3100                                       shstrtab_section);
3101   off_t off = align_address(*poff, oshdrs->addralign());
3102   oshdrs->set_address_and_file_offset(0, off);
3103   off += oshdrs->data_size();
3104   *poff = off;
3105   this->section_headers_ = oshdrs;
3106 }
3107
3108 // Count the allocated sections.
3109
3110 size_t
3111 Layout::allocated_output_section_count() const
3112 {
3113   size_t section_count = 0;
3114   for (Segment_list::const_iterator p = this->segment_list_.begin();
3115        p != this->segment_list_.end();
3116        ++p)
3117     section_count += (*p)->output_section_count();
3118   return section_count;
3119 }
3120
3121 // Create the dynamic symbol table.
3122
3123 void
3124 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3125                               Symbol_table* symtab,
3126                               Output_section** pdynstr,
3127                               unsigned int* plocal_dynamic_count,
3128                               std::vector<Symbol*>* pdynamic_symbols,
3129                               Versions* pversions)
3130 {
3131   // Count all the symbols in the dynamic symbol table, and set the
3132   // dynamic symbol indexes.
3133
3134   // Skip symbol 0, which is always all zeroes.
3135   unsigned int index = 1;
3136
3137   // Add STT_SECTION symbols for each Output section which needs one.
3138   for (Section_list::iterator p = this->section_list_.begin();
3139        p != this->section_list_.end();
3140        ++p)
3141     {
3142       if (!(*p)->needs_dynsym_index())
3143         (*p)->set_dynsym_index(-1U);
3144       else
3145         {
3146           (*p)->set_dynsym_index(index);
3147           ++index;
3148         }
3149     }
3150
3151   // Count the local symbols that need to go in the dynamic symbol table,
3152   // and set the dynamic symbol indexes.
3153   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3154        p != input_objects->relobj_end();
3155        ++p)
3156     {
3157       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3158       index = new_index;
3159     }
3160
3161   unsigned int local_symcount = index;
3162   *plocal_dynamic_count = local_symcount;
3163
3164   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3165                                      &this->dynpool_, pversions);
3166
3167   int symsize;
3168   unsigned int align;
3169   const int size = parameters->target().get_size();
3170   if (size == 32)
3171     {
3172       symsize = elfcpp::Elf_sizes<32>::sym_size;
3173       align = 4;
3174     }
3175   else if (size == 64)
3176     {
3177       symsize = elfcpp::Elf_sizes<64>::sym_size;
3178       align = 8;
3179     }
3180   else
3181     gold_unreachable();
3182
3183   // Create the dynamic symbol table section.
3184
3185   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3186                                                        elfcpp::SHT_DYNSYM,
3187                                                        elfcpp::SHF_ALLOC,
3188                                                        false,
3189                                                        ORDER_DYNAMIC_LINKER,
3190                                                        false);
3191
3192   Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3193                                                            align,
3194                                                            "** dynsym");
3195   dynsym->add_output_section_data(odata);
3196
3197   dynsym->set_info(local_symcount);
3198   dynsym->set_entsize(symsize);
3199   dynsym->set_addralign(align);
3200
3201   this->dynsym_section_ = dynsym;
3202
3203   Output_data_dynamic* const odyn = this->dynamic_data_;
3204   odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3205   odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3206
3207   // If there are more than SHN_LORESERVE allocated sections, we
3208   // create a .dynsym_shndx section.  It is possible that we don't
3209   // need one, because it is possible that there are no dynamic
3210   // symbols in any of the sections with indexes larger than
3211   // SHN_LORESERVE.  This is probably unusual, though, and at this
3212   // time we don't know the actual section indexes so it is
3213   // inconvenient to check.
3214   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3215     {
3216       Output_section* dynsym_xindex =
3217         this->choose_output_section(NULL, ".dynsym_shndx",
3218                                     elfcpp::SHT_SYMTAB_SHNDX,
3219                                     elfcpp::SHF_ALLOC,
3220                                     false, ORDER_DYNAMIC_LINKER, false);
3221
3222       this->dynsym_xindex_ = new Output_symtab_xindex(index);
3223
3224       dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3225
3226       dynsym_xindex->set_link_section(dynsym);
3227       dynsym_xindex->set_addralign(4);
3228       dynsym_xindex->set_entsize(4);
3229
3230       dynsym_xindex->set_after_input_sections();
3231
3232       // This tells the driver code to wait until the symbol table has
3233       // written out before writing out the postprocessing sections,
3234       // including the .dynsym_shndx section.
3235       this->any_postprocessing_sections_ = true;
3236     }
3237
3238   // Create the dynamic string table section.
3239
3240   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3241                                                        elfcpp::SHT_STRTAB,
3242                                                        elfcpp::SHF_ALLOC,
3243                                                        false,
3244                                                        ORDER_DYNAMIC_LINKER,
3245                                                        false);
3246
3247   Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3248   dynstr->add_output_section_data(strdata);
3249
3250   dynsym->set_link_section(dynstr);
3251   this->dynamic_section_->set_link_section(dynstr);
3252
3253   odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3254   odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3255
3256   *pdynstr = dynstr;
3257
3258   // Create the hash tables.
3259
3260   if (strcmp(parameters->options().hash_style(), "sysv") == 0
3261       || strcmp(parameters->options().hash_style(), "both") == 0)
3262     {
3263       unsigned char* phash;
3264       unsigned int hashlen;
3265       Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3266                                     &phash, &hashlen);
3267
3268       Output_section* hashsec =
3269         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3270                                     elfcpp::SHF_ALLOC, false,
3271                                     ORDER_DYNAMIC_LINKER, false);
3272
3273       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3274                                                                    hashlen,
3275                                                                    align,
3276                                                                    "** hash");
3277       hashsec->add_output_section_data(hashdata);
3278
3279       hashsec->set_link_section(dynsym);
3280       hashsec->set_entsize(4);
3281
3282       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3283     }
3284
3285   if (strcmp(parameters->options().hash_style(), "gnu") == 0
3286       || strcmp(parameters->options().hash_style(), "both") == 0)
3287     {
3288       unsigned char* phash;
3289       unsigned int hashlen;
3290       Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3291                                     &phash, &hashlen);
3292
3293       Output_section* hashsec =
3294         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3295                                     elfcpp::SHF_ALLOC, false,
3296                                     ORDER_DYNAMIC_LINKER, false);
3297
3298       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3299                                                                    hashlen,
3300                                                                    align,
3301                                                                    "** hash");
3302       hashsec->add_output_section_data(hashdata);
3303
3304       hashsec->set_link_section(dynsym);
3305
3306       // For a 64-bit target, the entries in .gnu.hash do not have a
3307       // uniform size, so we only set the entry size for a 32-bit
3308       // target.
3309       if (parameters->target().get_size() == 32)
3310         hashsec->set_entsize(4);
3311
3312       odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3313     }
3314 }
3315
3316 // Assign offsets to each local portion of the dynamic symbol table.
3317
3318 void
3319 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3320 {
3321   Output_section* dynsym = this->dynsym_section_;
3322   gold_assert(dynsym != NULL);
3323
3324   off_t off = dynsym->offset();
3325
3326   // Skip the dummy symbol at the start of the section.
3327   off += dynsym->entsize();
3328
3329   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3330        p != input_objects->relobj_end();
3331        ++p)
3332     {
3333       unsigned int count = (*p)->set_local_dynsym_offset(off);
3334       off += count * dynsym->entsize();
3335     }
3336 }
3337
3338 // Create the version sections.
3339
3340 void
3341 Layout::create_version_sections(const Versions* versions,
3342                                 const Symbol_table* symtab,
3343                                 unsigned int local_symcount,
3344                                 const std::vector<Symbol*>& dynamic_symbols,
3345                                 const Output_section* dynstr)
3346 {
3347   if (!versions->any_defs() && !versions->any_needs())
3348     return;
3349
3350   switch (parameters->size_and_endianness())
3351     {
3352 #ifdef HAVE_TARGET_32_LITTLE
3353     case Parameters::TARGET_32_LITTLE:
3354       this->sized_create_version_sections<32, false>(versions, symtab,
3355                                                      local_symcount,
3356                                                      dynamic_symbols, dynstr);
3357       break;
3358 #endif
3359 #ifdef HAVE_TARGET_32_BIG
3360     case Parameters::TARGET_32_BIG:
3361       this->sized_create_version_sections<32, true>(versions, symtab,
3362                                                     local_symcount,
3363                                                     dynamic_symbols, dynstr);
3364       break;
3365 #endif
3366 #ifdef HAVE_TARGET_64_LITTLE
3367     case Parameters::TARGET_64_LITTLE:
3368       this->sized_create_version_sections<64, false>(versions, symtab,
3369                                                      local_symcount,
3370                                                      dynamic_symbols, dynstr);
3371       break;
3372 #endif
3373 #ifdef HAVE_TARGET_64_BIG
3374     case Parameters::TARGET_64_BIG:
3375       this->sized_create_version_sections<64, true>(versions, symtab,
3376                                                     local_symcount,
3377                                                     dynamic_symbols, dynstr);
3378       break;
3379 #endif
3380     default:
3381       gold_unreachable();
3382     }
3383 }
3384
3385 // Create the version sections, sized version.
3386
3387 template<int size, bool big_endian>
3388 void
3389 Layout::sized_create_version_sections(
3390     const Versions* versions,
3391     const Symbol_table* symtab,
3392     unsigned int local_symcount,
3393     const std::vector<Symbol*>& dynamic_symbols,
3394     const Output_section* dynstr)
3395 {
3396   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3397                                                      elfcpp::SHT_GNU_versym,
3398                                                      elfcpp::SHF_ALLOC,
3399                                                      false,
3400                                                      ORDER_DYNAMIC_LINKER,
3401                                                      false);
3402
3403   unsigned char* vbuf;
3404   unsigned int vsize;
3405   versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
3406                                                       local_symcount,
3407                                                       dynamic_symbols,
3408                                                       &vbuf, &vsize);
3409
3410   Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
3411                                                             "** versions");
3412
3413   vsec->add_output_section_data(vdata);
3414   vsec->set_entsize(2);
3415   vsec->set_link_section(this->dynsym_section_);
3416
3417   Output_data_dynamic* const odyn = this->dynamic_data_;
3418   odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
3419
3420   if (versions->any_defs())
3421     {
3422       Output_section* vdsec;
3423       vdsec= this->choose_output_section(NULL, ".gnu.version_d",
3424                                          elfcpp::SHT_GNU_verdef,
3425                                          elfcpp::SHF_ALLOC,
3426                                          false, ORDER_DYNAMIC_LINKER, false);
3427
3428       unsigned char* vdbuf;
3429       unsigned int vdsize;
3430       unsigned int vdentries;
3431       versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
3432                                                        &vdsize, &vdentries);
3433
3434       Output_section_data* vddata =
3435         new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
3436
3437       vdsec->add_output_section_data(vddata);
3438       vdsec->set_link_section(dynstr);
3439       vdsec->set_info(vdentries);
3440
3441       odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
3442       odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
3443     }
3444
3445   if (versions->any_needs())
3446     {
3447       Output_section* vnsec;
3448       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
3449                                           elfcpp::SHT_GNU_verneed,
3450                                           elfcpp::SHF_ALLOC,
3451                                           false, ORDER_DYNAMIC_LINKER, false);
3452
3453       unsigned char* vnbuf;
3454       unsigned int vnsize;
3455       unsigned int vnentries;
3456       versions->need_section_contents<size, big_endian>(&this->dynpool_,
3457                                                         &vnbuf, &vnsize,
3458                                                         &vnentries);
3459
3460       Output_section_data* vndata =
3461         new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
3462
3463       vnsec->add_output_section_data(vndata);
3464       vnsec->set_link_section(dynstr);
3465       vnsec->set_info(vnentries);
3466
3467       odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
3468       odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
3469     }
3470 }
3471
3472 // Create the .interp section and PT_INTERP segment.
3473
3474 void
3475 Layout::create_interp(const Target* target)
3476 {
3477   const char* interp = parameters->options().dynamic_linker();
3478   if (interp == NULL)
3479     {
3480       interp = target->dynamic_linker();
3481       gold_assert(interp != NULL);
3482     }
3483
3484   size_t len = strlen(interp) + 1;
3485
3486   Output_section_data* odata = new Output_data_const(interp, len, 1);
3487
3488   Output_section* osec = this->choose_output_section(NULL, ".interp",
3489                                                      elfcpp::SHT_PROGBITS,
3490                                                      elfcpp::SHF_ALLOC,
3491                                                      false, ORDER_INTERP,
3492                                                      false);
3493   osec->add_output_section_data(odata);
3494
3495   if (!this->script_options_->saw_phdrs_clause())
3496     {
3497       Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
3498                                                        elfcpp::PF_R);
3499       oseg->add_output_section_to_nonload(osec, elfcpp::PF_R);
3500     }
3501 }
3502
3503 // Add dynamic tags for the PLT and the dynamic relocs.  This is
3504 // called by the target-specific code.  This does nothing if not doing
3505 // a dynamic link.
3506
3507 // USE_REL is true for REL relocs rather than RELA relocs.
3508
3509 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3510
3511 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3512 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
3513 // some targets have multiple reloc sections in PLT_REL.
3514
3515 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3516 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3517
3518 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3519 // executable.
3520
3521 void
3522 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
3523                                 const Output_data* plt_rel,
3524                                 const Output_data_reloc_generic* dyn_rel,
3525                                 bool add_debug, bool dynrel_includes_plt)
3526 {
3527   Output_data_dynamic* odyn = this->dynamic_data_;
3528   if (odyn == NULL)
3529     return;
3530
3531   if (plt_got != NULL && plt_got->output_section() != NULL)
3532     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
3533
3534   if (plt_rel != NULL && plt_rel->output_section() != NULL)
3535     {
3536       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
3537       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
3538       odyn->add_constant(elfcpp::DT_PLTREL,
3539                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
3540     }
3541
3542   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
3543     {
3544       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
3545                                 dyn_rel);
3546       if (plt_rel != NULL && dynrel_includes_plt)
3547         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3548                                dyn_rel, plt_rel);
3549       else
3550         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3551                                dyn_rel);
3552       const int size = parameters->target().get_size();
3553       elfcpp::DT rel_tag;
3554       int rel_size;
3555       if (use_rel)
3556         {
3557           rel_tag = elfcpp::DT_RELENT;
3558           if (size == 32)
3559             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
3560           else if (size == 64)
3561             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
3562           else
3563             gold_unreachable();
3564         }
3565       else
3566         {
3567           rel_tag = elfcpp::DT_RELAENT;
3568           if (size == 32)
3569             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
3570           else if (size == 64)
3571             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
3572           else
3573             gold_unreachable();
3574         }
3575       odyn->add_constant(rel_tag, rel_size);
3576
3577       if (parameters->options().combreloc())
3578         {
3579           size_t c = dyn_rel->relative_reloc_count();
3580           if (c > 0)
3581             odyn->add_constant((use_rel
3582                                 ? elfcpp::DT_RELCOUNT
3583                                 : elfcpp::DT_RELACOUNT),
3584                                c);
3585         }
3586     }
3587
3588   if (add_debug && !parameters->options().shared())
3589     {
3590       // The value of the DT_DEBUG tag is filled in by the dynamic
3591       // linker at run time, and used by the debugger.
3592       odyn->add_constant(elfcpp::DT_DEBUG, 0);
3593     }
3594 }
3595
3596 // Finish the .dynamic section and PT_DYNAMIC segment.
3597
3598 void
3599 Layout::finish_dynamic_section(const Input_objects* input_objects,
3600                                const Symbol_table* symtab)
3601 {
3602   if (!this->script_options_->saw_phdrs_clause())
3603     {
3604       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
3605                                                        (elfcpp::PF_R
3606                                                         | elfcpp::PF_W));
3607       oseg->add_output_section_to_nonload(this->dynamic_section_,
3608                                           elfcpp::PF_R | elfcpp::PF_W);
3609     }
3610
3611   Output_data_dynamic* const odyn = this->dynamic_data_;
3612
3613   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
3614        p != input_objects->dynobj_end();
3615        ++p)
3616     {
3617       if (!(*p)->is_needed()
3618           && (*p)->input_file()->options().as_needed())
3619         {
3620           // This dynamic object was linked with --as-needed, but it
3621           // is not needed.
3622           continue;
3623         }
3624
3625       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
3626     }
3627
3628   if (parameters->options().shared())
3629     {
3630       const char* soname = parameters->options().soname();
3631       if (soname != NULL)
3632         odyn->add_string(elfcpp::DT_SONAME, soname);
3633     }
3634
3635   Symbol* sym = symtab->lookup(parameters->options().init());
3636   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3637     odyn->add_symbol(elfcpp::DT_INIT, sym);
3638
3639   sym = symtab->lookup(parameters->options().fini());
3640   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3641     odyn->add_symbol(elfcpp::DT_FINI, sym);
3642
3643   // Look for .init_array, .preinit_array and .fini_array by checking
3644   // section types.
3645   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
3646       p != this->section_list_.end();
3647       ++p)
3648     switch((*p)->type())
3649       {
3650       case elfcpp::SHT_FINI_ARRAY:
3651         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
3652         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
3653         break;
3654       case elfcpp::SHT_INIT_ARRAY:
3655         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
3656         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
3657         break;
3658       case elfcpp::SHT_PREINIT_ARRAY:
3659         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
3660         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
3661         break;
3662       default:
3663         break;
3664       }
3665
3666   // Add a DT_RPATH entry if needed.
3667   const General_options::Dir_list& rpath(parameters->options().rpath());
3668   if (!rpath.empty())
3669     {
3670       std::string rpath_val;
3671       for (General_options::Dir_list::const_iterator p = rpath.begin();
3672            p != rpath.end();
3673            ++p)
3674         {
3675           if (rpath_val.empty())
3676             rpath_val = p->name();
3677           else
3678             {
3679               // Eliminate duplicates.
3680               General_options::Dir_list::const_iterator q;
3681               for (q = rpath.begin(); q != p; ++q)
3682                 if (q->name() == p->name())
3683                   break;
3684               if (q == p)
3685                 {
3686                   rpath_val += ':';
3687                   rpath_val += p->name();
3688                 }
3689             }
3690         }
3691
3692       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
3693       if (parameters->options().enable_new_dtags())
3694         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
3695     }
3696
3697   // Look for text segments that have dynamic relocations.
3698   bool have_textrel = false;
3699   if (!this->script_options_->saw_sections_clause())
3700     {
3701       for (Segment_list::const_iterator p = this->segment_list_.begin();
3702            p != this->segment_list_.end();
3703            ++p)
3704         {
3705           if (((*p)->flags() & elfcpp::PF_W) == 0
3706               && (*p)->has_dynamic_reloc())
3707             {
3708               have_textrel = true;
3709               break;
3710             }
3711         }
3712     }
3713   else
3714     {
3715       // We don't know the section -> segment mapping, so we are
3716       // conservative and just look for readonly sections with
3717       // relocations.  If those sections wind up in writable segments,
3718       // then we have created an unnecessary DT_TEXTREL entry.
3719       for (Section_list::const_iterator p = this->section_list_.begin();
3720            p != this->section_list_.end();
3721            ++p)
3722         {
3723           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
3724               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
3725               && ((*p)->has_dynamic_reloc()))
3726             {
3727               have_textrel = true;
3728               break;
3729             }
3730         }
3731     }
3732
3733   // Add a DT_FLAGS entry. We add it even if no flags are set so that
3734   // post-link tools can easily modify these flags if desired.
3735   unsigned int flags = 0;
3736   if (have_textrel)
3737     {
3738       // Add a DT_TEXTREL for compatibility with older loaders.
3739       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
3740       flags |= elfcpp::DF_TEXTREL;
3741
3742       if (parameters->options().text())
3743         gold_error(_("read-only segment has dynamic relocations"));
3744       else if (parameters->options().warn_shared_textrel()
3745                && parameters->options().shared())
3746         gold_warning(_("shared library text segment is not shareable"));
3747     }
3748   if (parameters->options().shared() && this->has_static_tls())
3749     flags |= elfcpp::DF_STATIC_TLS;
3750   if (parameters->options().origin())
3751     flags |= elfcpp::DF_ORIGIN;
3752   if (parameters->options().Bsymbolic())
3753     {
3754       flags |= elfcpp::DF_SYMBOLIC;
3755       // Add DT_SYMBOLIC for compatibility with older loaders.
3756       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
3757     }
3758   if (parameters->options().now())
3759     flags |= elfcpp::DF_BIND_NOW;
3760   odyn->add_constant(elfcpp::DT_FLAGS, flags);
3761
3762   flags = 0;
3763   if (parameters->options().initfirst())
3764     flags |= elfcpp::DF_1_INITFIRST;
3765   if (parameters->options().interpose())
3766     flags |= elfcpp::DF_1_INTERPOSE;
3767   if (parameters->options().loadfltr())
3768     flags |= elfcpp::DF_1_LOADFLTR;
3769   if (parameters->options().nodefaultlib())
3770     flags |= elfcpp::DF_1_NODEFLIB;
3771   if (parameters->options().nodelete())
3772     flags |= elfcpp::DF_1_NODELETE;
3773   if (parameters->options().nodlopen())
3774     flags |= elfcpp::DF_1_NOOPEN;
3775   if (parameters->options().nodump())
3776     flags |= elfcpp::DF_1_NODUMP;
3777   if (!parameters->options().shared())
3778     flags &= ~(elfcpp::DF_1_INITFIRST
3779                | elfcpp::DF_1_NODELETE
3780                | elfcpp::DF_1_NOOPEN);
3781   if (parameters->options().origin())
3782     flags |= elfcpp::DF_1_ORIGIN;
3783   if (parameters->options().now())
3784     flags |= elfcpp::DF_1_NOW;
3785   if (flags)
3786     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
3787 }
3788
3789 // Set the size of the _DYNAMIC symbol table to be the size of the
3790 // dynamic data.
3791
3792 void
3793 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
3794 {
3795   Output_data_dynamic* const odyn = this->dynamic_data_;
3796   odyn->finalize_data_size();
3797   off_t data_size = odyn->data_size();
3798   const int size = parameters->target().get_size();
3799   if (size == 32)
3800     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
3801   else if (size == 64)
3802     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
3803   else
3804     gold_unreachable();
3805 }
3806
3807 // The mapping of input section name prefixes to output section names.
3808 // In some cases one prefix is itself a prefix of another prefix; in
3809 // such a case the longer prefix must come first.  These prefixes are
3810 // based on the GNU linker default ELF linker script.
3811
3812 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
3813 const Layout::Section_name_mapping Layout::section_name_mapping[] =
3814 {
3815   MAPPING_INIT(".text.", ".text"),
3816   MAPPING_INIT(".ctors.", ".ctors"),
3817   MAPPING_INIT(".dtors.", ".dtors"),
3818   MAPPING_INIT(".rodata.", ".rodata"),
3819   MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
3820   MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
3821   MAPPING_INIT(".data.", ".data"),
3822   MAPPING_INIT(".bss.", ".bss"),
3823   MAPPING_INIT(".tdata.", ".tdata"),
3824   MAPPING_INIT(".tbss.", ".tbss"),
3825   MAPPING_INIT(".init_array.", ".init_array"),
3826   MAPPING_INIT(".fini_array.", ".fini_array"),
3827   MAPPING_INIT(".sdata.", ".sdata"),
3828   MAPPING_INIT(".sbss.", ".sbss"),
3829   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
3830   // differently depending on whether it is creating a shared library.
3831   MAPPING_INIT(".sdata2.", ".sdata"),
3832   MAPPING_INIT(".sbss2.", ".sbss"),
3833   MAPPING_INIT(".lrodata.", ".lrodata"),
3834   MAPPING_INIT(".ldata.", ".ldata"),
3835   MAPPING_INIT(".lbss.", ".lbss"),
3836   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
3837   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
3838   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
3839   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
3840   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
3841   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
3842   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
3843   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
3844   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
3845   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
3846   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
3847   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
3848   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
3849   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
3850   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
3851   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
3852   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
3853   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
3854   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
3855   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
3856   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
3857 };
3858 #undef MAPPING_INIT
3859
3860 const int Layout::section_name_mapping_count =
3861   (sizeof(Layout::section_name_mapping)
3862    / sizeof(Layout::section_name_mapping[0]));
3863
3864 // Choose the output section name to use given an input section name.
3865 // Set *PLEN to the length of the name.  *PLEN is initialized to the
3866 // length of NAME.
3867
3868 const char*
3869 Layout::output_section_name(const char* name, size_t* plen)
3870 {
3871   // gcc 4.3 generates the following sorts of section names when it
3872   // needs a section name specific to a function:
3873   //   .text.FN
3874   //   .rodata.FN
3875   //   .sdata2.FN
3876   //   .data.FN
3877   //   .data.rel.FN
3878   //   .data.rel.local.FN
3879   //   .data.rel.ro.FN
3880   //   .data.rel.ro.local.FN
3881   //   .sdata.FN
3882   //   .bss.FN
3883   //   .sbss.FN
3884   //   .tdata.FN
3885   //   .tbss.FN
3886
3887   // The GNU linker maps all of those to the part before the .FN,
3888   // except that .data.rel.local.FN is mapped to .data, and
3889   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
3890   // beginning with .data.rel.ro.local are grouped together.
3891
3892   // For an anonymous namespace, the string FN can contain a '.'.
3893
3894   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
3895   // GNU linker maps to .rodata.
3896
3897   // The .data.rel.ro sections are used with -z relro.  The sections
3898   // are recognized by name.  We use the same names that the GNU
3899   // linker does for these sections.
3900
3901   // It is hard to handle this in a principled way, so we don't even
3902   // try.  We use a table of mappings.  If the input section name is
3903   // not found in the table, we simply use it as the output section
3904   // name.
3905
3906   const Section_name_mapping* psnm = section_name_mapping;
3907   for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
3908     {
3909       if (strncmp(name, psnm->from, psnm->fromlen) == 0)
3910         {
3911           *plen = psnm->tolen;
3912           return psnm->to;
3913         }
3914     }
3915
3916   // Compressed debug sections should be mapped to the corresponding
3917   // uncompressed section.
3918   if (is_compressed_debug_section(name))
3919     {
3920       size_t len = strlen(name);
3921       char* uncompressed_name = new char[len];
3922       uncompressed_name[0] = '.';
3923       gold_assert(name[0] == '.' && name[1] == 'z');
3924       strncpy(&uncompressed_name[1], &name[2], len - 2);
3925       uncompressed_name[len - 1] = '\0';
3926       *plen = len - 1;
3927       return uncompressed_name;
3928     }
3929
3930   return name;
3931 }
3932
3933 // Check if a comdat group or .gnu.linkonce section with the given
3934 // NAME is selected for the link.  If there is already a section,
3935 // *KEPT_SECTION is set to point to the existing section and the
3936 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
3937 // IS_GROUP_NAME are recorded for this NAME in the layout object,
3938 // *KEPT_SECTION is set to the internal copy and the function returns
3939 // true.
3940
3941 bool
3942 Layout::find_or_add_kept_section(const std::string& name,
3943                                  Relobj* object,
3944                                  unsigned int shndx,
3945                                  bool is_comdat,
3946                                  bool is_group_name,
3947                                  Kept_section** kept_section)
3948 {
3949   // It's normal to see a couple of entries here, for the x86 thunk
3950   // sections.  If we see more than a few, we're linking a C++
3951   // program, and we resize to get more space to minimize rehashing.
3952   if (this->signatures_.size() > 4
3953       && !this->resized_signatures_)
3954     {
3955       reserve_unordered_map(&this->signatures_,
3956                             this->number_of_input_files_ * 64);
3957       this->resized_signatures_ = true;
3958     }
3959
3960   Kept_section candidate;
3961   std::pair<Signatures::iterator, bool> ins =
3962     this->signatures_.insert(std::make_pair(name, candidate));
3963
3964   if (kept_section != NULL)
3965     *kept_section = &ins.first->second;
3966   if (ins.second)
3967     {
3968       // This is the first time we've seen this signature.
3969       ins.first->second.set_object(object);
3970       ins.first->second.set_shndx(shndx);
3971       if (is_comdat)
3972         ins.first->second.set_is_comdat();
3973       if (is_group_name)
3974         ins.first->second.set_is_group_name();
3975       return true;
3976     }
3977
3978   // We have already seen this signature.
3979
3980   if (ins.first->second.is_group_name())
3981     {
3982       // We've already seen a real section group with this signature.
3983       // If the kept group is from a plugin object, and we're in the
3984       // replacement phase, accept the new one as a replacement.
3985       if (ins.first->second.object() == NULL
3986           && parameters->options().plugins()->in_replacement_phase())
3987         {
3988           ins.first->second.set_object(object);
3989           ins.first->second.set_shndx(shndx);
3990           return true;
3991         }
3992       return false;
3993     }
3994   else if (is_group_name)
3995     {
3996       // This is a real section group, and we've already seen a
3997       // linkonce section with this signature.  Record that we've seen
3998       // a section group, and don't include this section group.
3999       ins.first->second.set_is_group_name();
4000       return false;
4001     }
4002   else
4003     {
4004       // We've already seen a linkonce section and this is a linkonce
4005       // section.  These don't block each other--this may be the same
4006       // symbol name with different section types.
4007       return true;
4008     }
4009 }
4010
4011 // Store the allocated sections into the section list.
4012
4013 void
4014 Layout::get_allocated_sections(Section_list* section_list) const
4015 {
4016   for (Section_list::const_iterator p = this->section_list_.begin();
4017        p != this->section_list_.end();
4018        ++p)
4019     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4020       section_list->push_back(*p);
4021 }
4022
4023 // Create an output segment.
4024
4025 Output_segment*
4026 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4027 {
4028   gold_assert(!parameters->options().relocatable());
4029   Output_segment* oseg = new Output_segment(type, flags);
4030   this->segment_list_.push_back(oseg);
4031
4032   if (type == elfcpp::PT_TLS)
4033     this->tls_segment_ = oseg;
4034   else if (type == elfcpp::PT_GNU_RELRO)
4035     this->relro_segment_ = oseg;
4036
4037   return oseg;
4038 }
4039
4040 // Write out the Output_sections.  Most won't have anything to write,
4041 // since most of the data will come from input sections which are
4042 // handled elsewhere.  But some Output_sections do have Output_data.
4043
4044 void
4045 Layout::write_output_sections(Output_file* of) const
4046 {
4047   for (Section_list::const_iterator p = this->section_list_.begin();
4048        p != this->section_list_.end();
4049        ++p)
4050     {
4051       if (!(*p)->after_input_sections())
4052         (*p)->write(of);
4053     }
4054 }
4055
4056 // Write out data not associated with a section or the symbol table.
4057
4058 void
4059 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4060 {
4061   if (!parameters->options().strip_all())
4062     {
4063       const Output_section* symtab_section = this->symtab_section_;
4064       for (Section_list::const_iterator p = this->section_list_.begin();
4065            p != this->section_list_.end();
4066            ++p)
4067         {
4068           if ((*p)->needs_symtab_index())
4069             {
4070               gold_assert(symtab_section != NULL);
4071               unsigned int index = (*p)->symtab_index();
4072               gold_assert(index > 0 && index != -1U);
4073               off_t off = (symtab_section->offset()
4074                            + index * symtab_section->entsize());
4075               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4076             }
4077         }
4078     }
4079
4080   const Output_section* dynsym_section = this->dynsym_section_;
4081   for (Section_list::const_iterator p = this->section_list_.begin();
4082        p != this->section_list_.end();
4083        ++p)
4084     {
4085       if ((*p)->needs_dynsym_index())
4086         {
4087           gold_assert(dynsym_section != NULL);
4088           unsigned int index = (*p)->dynsym_index();
4089           gold_assert(index > 0 && index != -1U);
4090           off_t off = (dynsym_section->offset()
4091                        + index * dynsym_section->entsize());
4092           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4093         }
4094     }
4095
4096   // Write out the Output_data which are not in an Output_section.
4097   for (Data_list::const_iterator p = this->special_output_list_.begin();
4098        p != this->special_output_list_.end();
4099        ++p)
4100     (*p)->write(of);
4101 }
4102
4103 // Write out the Output_sections which can only be written after the
4104 // input sections are complete.
4105
4106 void
4107 Layout::write_sections_after_input_sections(Output_file* of)
4108 {
4109   // Determine the final section offsets, and thus the final output
4110   // file size.  Note we finalize the .shstrab last, to allow the
4111   // after_input_section sections to modify their section-names before
4112   // writing.
4113   if (this->any_postprocessing_sections_)
4114     {
4115       off_t off = this->output_file_size_;
4116       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4117
4118       // Now that we've finalized the names, we can finalize the shstrab.
4119       off =
4120         this->set_section_offsets(off,
4121                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4122
4123       if (off > this->output_file_size_)
4124         {
4125           of->resize(off);
4126           this->output_file_size_ = off;
4127         }
4128     }
4129
4130   for (Section_list::const_iterator p = this->section_list_.begin();
4131        p != this->section_list_.end();
4132        ++p)
4133     {
4134       if ((*p)->after_input_sections())
4135         (*p)->write(of);
4136     }
4137
4138   this->section_headers_->write(of);
4139 }
4140
4141 // If the build ID requires computing a checksum, do so here, and
4142 // write it out.  We compute a checksum over the entire file because
4143 // that is simplest.
4144
4145 void
4146 Layout::write_build_id(Output_file* of) const
4147 {
4148   if (this->build_id_note_ == NULL)
4149     return;
4150
4151   const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4152
4153   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4154                                           this->build_id_note_->data_size());
4155
4156   const char* style = parameters->options().build_id();
4157   if (strcmp(style, "sha1") == 0)
4158     {
4159       sha1_ctx ctx;
4160       sha1_init_ctx(&ctx);
4161       sha1_process_bytes(iv, this->output_file_size_, &ctx);
4162       sha1_finish_ctx(&ctx, ov);
4163     }
4164   else if (strcmp(style, "md5") == 0)
4165     {
4166       md5_ctx ctx;
4167       md5_init_ctx(&ctx);
4168       md5_process_bytes(iv, this->output_file_size_, &ctx);
4169       md5_finish_ctx(&ctx, ov);
4170     }
4171   else
4172     gold_unreachable();
4173
4174   of->write_output_view(this->build_id_note_->offset(),
4175                         this->build_id_note_->data_size(),
4176                         ov);
4177
4178   of->free_input_view(0, this->output_file_size_, iv);
4179 }
4180
4181 // Write out a binary file.  This is called after the link is
4182 // complete.  IN is the temporary output file we used to generate the
4183 // ELF code.  We simply walk through the segments, read them from
4184 // their file offset in IN, and write them to their load address in
4185 // the output file.  FIXME: with a bit more work, we could support
4186 // S-records and/or Intel hex format here.
4187
4188 void
4189 Layout::write_binary(Output_file* in) const
4190 {
4191   gold_assert(parameters->options().oformat_enum()
4192               == General_options::OBJECT_FORMAT_BINARY);
4193
4194   // Get the size of the binary file.
4195   uint64_t max_load_address = 0;
4196   for (Segment_list::const_iterator p = this->segment_list_.begin();
4197        p != this->segment_list_.end();
4198        ++p)
4199     {
4200       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4201         {
4202           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4203           if (max_paddr > max_load_address)
4204             max_load_address = max_paddr;
4205         }
4206     }
4207
4208   Output_file out(parameters->options().output_file_name());
4209   out.open(max_load_address);
4210
4211   for (Segment_list::const_iterator p = this->segment_list_.begin();
4212        p != this->segment_list_.end();
4213        ++p)
4214     {
4215       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4216         {
4217           const unsigned char* vin = in->get_input_view((*p)->offset(),
4218                                                         (*p)->filesz());
4219           unsigned char* vout = out.get_output_view((*p)->paddr(),
4220                                                     (*p)->filesz());
4221           memcpy(vout, vin, (*p)->filesz());
4222           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4223           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4224         }
4225     }
4226
4227   out.close();
4228 }
4229
4230 // Print the output sections to the map file.
4231
4232 void
4233 Layout::print_to_mapfile(Mapfile* mapfile) const
4234 {
4235   for (Segment_list::const_iterator p = this->segment_list_.begin();
4236        p != this->segment_list_.end();
4237        ++p)
4238     (*p)->print_sections_to_mapfile(mapfile);
4239 }
4240
4241 // Print statistical information to stderr.  This is used for --stats.
4242
4243 void
4244 Layout::print_stats() const
4245 {
4246   this->namepool_.print_stats("section name pool");
4247   this->sympool_.print_stats("output symbol name pool");
4248   this->dynpool_.print_stats("dynamic name pool");
4249
4250   for (Section_list::const_iterator p = this->section_list_.begin();
4251        p != this->section_list_.end();
4252        ++p)
4253     (*p)->print_merge_stats();
4254 }
4255
4256 // Write_sections_task methods.
4257
4258 // We can always run this task.
4259
4260 Task_token*
4261 Write_sections_task::is_runnable()
4262 {
4263   return NULL;
4264 }
4265
4266 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4267 // when finished.
4268
4269 void
4270 Write_sections_task::locks(Task_locker* tl)
4271 {
4272   tl->add(this, this->output_sections_blocker_);
4273   tl->add(this, this->final_blocker_);
4274 }
4275
4276 // Run the task--write out the data.
4277
4278 void
4279 Write_sections_task::run(Workqueue*)
4280 {
4281   this->layout_->write_output_sections(this->of_);
4282 }
4283
4284 // Write_data_task methods.
4285
4286 // We can always run this task.
4287
4288 Task_token*
4289 Write_data_task::is_runnable()
4290 {
4291   return NULL;
4292 }
4293
4294 // We need to unlock FINAL_BLOCKER when finished.
4295
4296 void
4297 Write_data_task::locks(Task_locker* tl)
4298 {
4299   tl->add(this, this->final_blocker_);
4300 }
4301
4302 // Run the task--write out the data.
4303
4304 void
4305 Write_data_task::run(Workqueue*)
4306 {
4307   this->layout_->write_data(this->symtab_, this->of_);
4308 }
4309
4310 // Write_symbols_task methods.
4311
4312 // We can always run this task.
4313
4314 Task_token*
4315 Write_symbols_task::is_runnable()
4316 {
4317   return NULL;
4318 }
4319
4320 // We need to unlock FINAL_BLOCKER when finished.
4321
4322 void
4323 Write_symbols_task::locks(Task_locker* tl)
4324 {
4325   tl->add(this, this->final_blocker_);
4326 }
4327
4328 // Run the task--write out the symbols.
4329
4330 void
4331 Write_symbols_task::run(Workqueue*)
4332 {
4333   this->symtab_->write_globals(this->sympool_, this->dynpool_,
4334                                this->layout_->symtab_xindex(),
4335                                this->layout_->dynsym_xindex(), this->of_);
4336 }
4337
4338 // Write_after_input_sections_task methods.
4339
4340 // We can only run this task after the input sections have completed.
4341
4342 Task_token*
4343 Write_after_input_sections_task::is_runnable()
4344 {
4345   if (this->input_sections_blocker_->is_blocked())
4346     return this->input_sections_blocker_;
4347   return NULL;
4348 }
4349
4350 // We need to unlock FINAL_BLOCKER when finished.
4351
4352 void
4353 Write_after_input_sections_task::locks(Task_locker* tl)
4354 {
4355   tl->add(this, this->final_blocker_);
4356 }
4357
4358 // Run the task.
4359
4360 void
4361 Write_after_input_sections_task::run(Workqueue*)
4362 {
4363   this->layout_->write_sections_after_input_sections(this->of_);
4364 }
4365
4366 // Close_task_runner methods.
4367
4368 // Run the task--close the file.
4369
4370 void
4371 Close_task_runner::run(Workqueue*, const Task*)
4372 {
4373   // If we need to compute a checksum for the BUILD if, we do so here.
4374   this->layout_->write_build_id(this->of_);
4375
4376   // If we've been asked to create a binary file, we do so here.
4377   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
4378     this->layout_->write_binary(this->of_);
4379
4380   this->of_->close();
4381 }
4382
4383 // Instantiate the templates we need.  We could use the configure
4384 // script to restrict this to only the ones for implemented targets.
4385
4386 #ifdef HAVE_TARGET_32_LITTLE
4387 template
4388 Output_section*
4389 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
4390                           const char* name,
4391                           const elfcpp::Shdr<32, false>& shdr,
4392                           unsigned int, unsigned int, off_t*);
4393 #endif
4394
4395 #ifdef HAVE_TARGET_32_BIG
4396 template
4397 Output_section*
4398 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
4399                          const char* name,
4400                          const elfcpp::Shdr<32, true>& shdr,
4401                          unsigned int, unsigned int, off_t*);
4402 #endif
4403
4404 #ifdef HAVE_TARGET_64_LITTLE
4405 template
4406 Output_section*
4407 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
4408                           const char* name,
4409                           const elfcpp::Shdr<64, false>& shdr,
4410                           unsigned int, unsigned int, off_t*);
4411 #endif
4412
4413 #ifdef HAVE_TARGET_64_BIG
4414 template
4415 Output_section*
4416 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
4417                          const char* name,
4418                          const elfcpp::Shdr<64, true>& shdr,
4419                          unsigned int, unsigned int, off_t*);
4420 #endif
4421
4422 #ifdef HAVE_TARGET_32_LITTLE
4423 template
4424 Output_section*
4425 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
4426                                 unsigned int reloc_shndx,
4427                                 const elfcpp::Shdr<32, false>& shdr,
4428                                 Output_section* data_section,
4429                                 Relocatable_relocs* rr);
4430 #endif
4431
4432 #ifdef HAVE_TARGET_32_BIG
4433 template
4434 Output_section*
4435 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
4436                                unsigned int reloc_shndx,
4437                                const elfcpp::Shdr<32, true>& shdr,
4438                                Output_section* data_section,
4439                                Relocatable_relocs* rr);
4440 #endif
4441
4442 #ifdef HAVE_TARGET_64_LITTLE
4443 template
4444 Output_section*
4445 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
4446                                 unsigned int reloc_shndx,
4447                                 const elfcpp::Shdr<64, false>& shdr,
4448                                 Output_section* data_section,
4449                                 Relocatable_relocs* rr);
4450 #endif
4451
4452 #ifdef HAVE_TARGET_64_BIG
4453 template
4454 Output_section*
4455 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
4456                                unsigned int reloc_shndx,
4457                                const elfcpp::Shdr<64, true>& shdr,
4458                                Output_section* data_section,
4459                                Relocatable_relocs* rr);
4460 #endif
4461
4462 #ifdef HAVE_TARGET_32_LITTLE
4463 template
4464 void
4465 Layout::layout_group<32, false>(Symbol_table* symtab,
4466                                 Sized_relobj<32, false>* object,
4467                                 unsigned int,
4468                                 const char* group_section_name,
4469                                 const char* signature,
4470                                 const elfcpp::Shdr<32, false>& shdr,
4471                                 elfcpp::Elf_Word flags,
4472                                 std::vector<unsigned int>* shndxes);
4473 #endif
4474
4475 #ifdef HAVE_TARGET_32_BIG
4476 template
4477 void
4478 Layout::layout_group<32, true>(Symbol_table* symtab,
4479                                Sized_relobj<32, true>* object,
4480                                unsigned int,
4481                                const char* group_section_name,
4482                                const char* signature,
4483                                const elfcpp::Shdr<32, true>& shdr,
4484                                elfcpp::Elf_Word flags,
4485                                std::vector<unsigned int>* shndxes);
4486 #endif
4487
4488 #ifdef HAVE_TARGET_64_LITTLE
4489 template
4490 void
4491 Layout::layout_group<64, false>(Symbol_table* symtab,
4492                                 Sized_relobj<64, false>* object,
4493                                 unsigned int,
4494                                 const char* group_section_name,
4495                                 const char* signature,
4496                                 const elfcpp::Shdr<64, false>& shdr,
4497                                 elfcpp::Elf_Word flags,
4498                                 std::vector<unsigned int>* shndxes);
4499 #endif
4500
4501 #ifdef HAVE_TARGET_64_BIG
4502 template
4503 void
4504 Layout::layout_group<64, true>(Symbol_table* symtab,
4505                                Sized_relobj<64, true>* object,
4506                                unsigned int,
4507                                const char* group_section_name,
4508                                const char* signature,
4509                                const elfcpp::Shdr<64, true>& shdr,
4510                                elfcpp::Elf_Word flags,
4511                                std::vector<unsigned int>* shndxes);
4512 #endif
4513
4514 #ifdef HAVE_TARGET_32_LITTLE
4515 template
4516 Output_section*
4517 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
4518                                    const unsigned char* symbols,
4519                                    off_t symbols_size,
4520                                    const unsigned char* symbol_names,
4521                                    off_t symbol_names_size,
4522                                    unsigned int shndx,
4523                                    const elfcpp::Shdr<32, false>& shdr,
4524                                    unsigned int reloc_shndx,
4525                                    unsigned int reloc_type,
4526                                    off_t* off);
4527 #endif
4528
4529 #ifdef HAVE_TARGET_32_BIG
4530 template
4531 Output_section*
4532 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
4533                                    const unsigned char* symbols,
4534                                    off_t symbols_size,
4535                                   const unsigned char* symbol_names,
4536                                   off_t symbol_names_size,
4537                                   unsigned int shndx,
4538                                   const elfcpp::Shdr<32, true>& shdr,
4539                                   unsigned int reloc_shndx,
4540                                   unsigned int reloc_type,
4541                                   off_t* off);
4542 #endif
4543
4544 #ifdef HAVE_TARGET_64_LITTLE
4545 template
4546 Output_section*
4547 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
4548                                    const unsigned char* symbols,
4549                                    off_t symbols_size,
4550                                    const unsigned char* symbol_names,
4551                                    off_t symbol_names_size,
4552                                    unsigned int shndx,
4553                                    const elfcpp::Shdr<64, false>& shdr,
4554                                    unsigned int reloc_shndx,
4555                                    unsigned int reloc_type,
4556                                    off_t* off);
4557 #endif
4558
4559 #ifdef HAVE_TARGET_64_BIG
4560 template
4561 Output_section*
4562 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
4563                                    const unsigned char* symbols,
4564                                    off_t symbols_size,
4565                                   const unsigned char* symbol_names,
4566                                   off_t symbol_names_size,
4567                                   unsigned int shndx,
4568                                   const elfcpp::Shdr<64, true>& shdr,
4569                                   unsigned int reloc_shndx,
4570                                   unsigned int reloc_type,
4571                                   off_t* off);
4572 #endif
4573
4574 } // End namespace gold.