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->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 or executable,
1175   // so that is how we search for them.
1176   // Large data sections also go into their own PT_LOAD segment.
1177   // People who need segments sorted on some other basis will
1178   // have to use a linker script.
1179
1180   Segment_list::const_iterator p;
1181   for (p = this->segment_list_.begin();
1182        p != this->segment_list_.end();
1183        ++p)
1184     {
1185       if ((*p)->type() != elfcpp::PT_LOAD)
1186         continue;
1187       if (!parameters->options().omagic()
1188           && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1189         continue;
1190       if (parameters->options().rosegment()
1191           && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1192         continue;
1193       // If -Tbss was specified, we need to separate the data and BSS
1194       // segments.
1195       if (parameters->options().user_set_Tbss())
1196         {
1197           if ((os->type() == elfcpp::SHT_NOBITS)
1198               == (*p)->has_any_data_sections())
1199             continue;
1200         }
1201       if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1202         continue;
1203
1204       if (is_address_set)
1205         {
1206           if ((*p)->are_addresses_set())
1207             continue;
1208
1209           (*p)->add_initial_output_data(os);
1210           (*p)->update_flags_for_output_section(seg_flags);
1211           (*p)->set_addresses(addr, addr);
1212           break;
1213         }
1214
1215       (*p)->add_output_section_to_load(this, os, seg_flags);
1216       break;
1217     }
1218
1219   if (p == this->segment_list_.end())
1220     {
1221       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1222                                                        seg_flags);
1223       if (os->is_large_data_section())
1224         oseg->set_is_large_data_segment();
1225       oseg->add_output_section_to_load(this, os, seg_flags);
1226       if (is_address_set)
1227         oseg->set_addresses(addr, addr);
1228     }
1229
1230   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1231   // segment.
1232   if (os->type() == elfcpp::SHT_NOTE)
1233     {
1234       // See if we already have an equivalent PT_NOTE segment.
1235       for (p = this->segment_list_.begin();
1236            p != segment_list_.end();
1237            ++p)
1238         {
1239           if ((*p)->type() == elfcpp::PT_NOTE
1240               && (((*p)->flags() & elfcpp::PF_W)
1241                   == (seg_flags & elfcpp::PF_W)))
1242             {
1243               (*p)->add_output_section_to_nonload(os, seg_flags);
1244               break;
1245             }
1246         }
1247
1248       if (p == this->segment_list_.end())
1249         {
1250           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1251                                                            seg_flags);
1252           oseg->add_output_section_to_nonload(os, seg_flags);
1253         }
1254     }
1255
1256   // If we see a loadable SHF_TLS section, we create a PT_TLS
1257   // segment.  There can only be one such segment.
1258   if ((flags & elfcpp::SHF_TLS) != 0)
1259     {
1260       if (this->tls_segment_ == NULL)
1261         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1262       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1263     }
1264
1265   // If -z relro is in effect, and we see a relro section, we create a
1266   // PT_GNU_RELRO segment.  There can only be one such segment.
1267   if (os->is_relro() && parameters->options().relro())
1268     {
1269       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1270       if (this->relro_segment_ == NULL)
1271         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1272       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1273     }
1274 }
1275
1276 // Make an output section for a script.
1277
1278 Output_section*
1279 Layout::make_output_section_for_script(
1280     const char* name,
1281     Script_sections::Section_type section_type)
1282 {
1283   name = this->namepool_.add(name, false, NULL);
1284   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1285   if (section_type == Script_sections::ST_NOLOAD)
1286     sh_flags = 0;
1287   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1288                                                  sh_flags, ORDER_INVALID,
1289                                                  false);
1290   os->set_found_in_sections_clause();
1291   if (section_type == Script_sections::ST_NOLOAD)
1292     os->set_is_noload();
1293   return os;
1294 }
1295
1296 // Return the number of segments we expect to see.
1297
1298 size_t
1299 Layout::expected_segment_count() const
1300 {
1301   size_t ret = this->segment_list_.size();
1302
1303   // If we didn't see a SECTIONS clause in a linker script, we should
1304   // already have the complete list of segments.  Otherwise we ask the
1305   // SECTIONS clause how many segments it expects, and add in the ones
1306   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1307
1308   if (!this->script_options_->saw_sections_clause())
1309     return ret;
1310   else
1311     {
1312       const Script_sections* ss = this->script_options_->script_sections();
1313       return ret + ss->expected_segment_count(this);
1314     }
1315 }
1316
1317 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
1318 // is whether we saw a .note.GNU-stack section in the object file.
1319 // GNU_STACK_FLAGS is the section flags.  The flags give the
1320 // protection required for stack memory.  We record this in an
1321 // executable as a PT_GNU_STACK segment.  If an object file does not
1322 // have a .note.GNU-stack segment, we must assume that it is an old
1323 // object.  On some targets that will force an executable stack.
1324
1325 void
1326 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
1327 {
1328   if (!seen_gnu_stack)
1329     this->input_without_gnu_stack_note_ = true;
1330   else
1331     {
1332       this->input_with_gnu_stack_note_ = true;
1333       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1334         this->input_requires_executable_stack_ = true;
1335     }
1336 }
1337
1338 // Create automatic note sections.
1339
1340 void
1341 Layout::create_notes()
1342 {
1343   this->create_gold_note();
1344   this->create_executable_stack_info();
1345   this->create_build_id();
1346 }
1347
1348 // Create the dynamic sections which are needed before we read the
1349 // relocs.
1350
1351 void
1352 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1353 {
1354   if (parameters->doing_static_link())
1355     return;
1356
1357   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1358                                                        elfcpp::SHT_DYNAMIC,
1359                                                        (elfcpp::SHF_ALLOC
1360                                                         | elfcpp::SHF_WRITE),
1361                                                        false, ORDER_RELRO,
1362                                                        true);
1363
1364   this->dynamic_symbol_ =
1365     symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
1366                                   this->dynamic_section_, 0, 0,
1367                                   elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1368                                   elfcpp::STV_HIDDEN, 0, false, false);
1369
1370   this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
1371
1372   this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1373 }
1374
1375 // For each output section whose name can be represented as C symbol,
1376 // define __start and __stop symbols for the section.  This is a GNU
1377 // extension.
1378
1379 void
1380 Layout::define_section_symbols(Symbol_table* symtab)
1381 {
1382   for (Section_list::const_iterator p = this->section_list_.begin();
1383        p != this->section_list_.end();
1384        ++p)
1385     {
1386       const char* const name = (*p)->name();
1387       if (is_cident(name))
1388         {
1389           const std::string name_string(name);
1390           const std::string start_name(cident_section_start_prefix
1391                                        + name_string);
1392           const std::string stop_name(cident_section_stop_prefix
1393                                       + name_string);
1394
1395           symtab->define_in_output_data(start_name.c_str(),
1396                                         NULL, // version
1397                                         Symbol_table::PREDEFINED,
1398                                         *p,
1399                                         0, // value
1400                                         0, // symsize
1401                                         elfcpp::STT_NOTYPE,
1402                                         elfcpp::STB_GLOBAL,
1403                                         elfcpp::STV_DEFAULT,
1404                                         0, // nonvis
1405                                         false, // offset_is_from_end
1406                                         true); // only_if_ref
1407
1408           symtab->define_in_output_data(stop_name.c_str(),
1409                                         NULL, // version
1410                                         Symbol_table::PREDEFINED,
1411                                         *p,
1412                                         0, // value
1413                                         0, // symsize
1414                                         elfcpp::STT_NOTYPE,
1415                                         elfcpp::STB_GLOBAL,
1416                                         elfcpp::STV_DEFAULT,
1417                                         0, // nonvis
1418                                         true, // offset_is_from_end
1419                                         true); // only_if_ref
1420         }
1421     }
1422 }
1423
1424 // Define symbols for group signatures.
1425
1426 void
1427 Layout::define_group_signatures(Symbol_table* symtab)
1428 {
1429   for (Group_signatures::iterator p = this->group_signatures_.begin();
1430        p != this->group_signatures_.end();
1431        ++p)
1432     {
1433       Symbol* sym = symtab->lookup(p->signature, NULL);
1434       if (sym != NULL)
1435         p->section->set_info_symndx(sym);
1436       else
1437         {
1438           // Force the name of the group section to the group
1439           // signature, and use the group's section symbol as the
1440           // signature symbol.
1441           if (strcmp(p->section->name(), p->signature) != 0)
1442             {
1443               const char* name = this->namepool_.add(p->signature,
1444                                                      true, NULL);
1445               p->section->set_name(name);
1446             }
1447           p->section->set_needs_symtab_index();
1448           p->section->set_info_section_symndx(p->section);
1449         }
1450     }
1451
1452   this->group_signatures_.clear();
1453 }
1454
1455 // Find the first read-only PT_LOAD segment, creating one if
1456 // necessary.
1457
1458 Output_segment*
1459 Layout::find_first_load_seg()
1460 {
1461   Output_segment* best = NULL;
1462   for (Segment_list::const_iterator p = this->segment_list_.begin();
1463        p != this->segment_list_.end();
1464        ++p)
1465     {
1466       if ((*p)->type() == elfcpp::PT_LOAD
1467           && ((*p)->flags() & elfcpp::PF_R) != 0
1468           && (parameters->options().omagic()
1469               || ((*p)->flags() & elfcpp::PF_W) == 0))
1470         {
1471           if (best == NULL || this->segment_precedes(*p, best))
1472             best = *p;
1473         }
1474     }
1475   if (best != NULL)
1476     return best;
1477
1478   gold_assert(!this->script_options_->saw_phdrs_clause());
1479
1480   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1481                                                        elfcpp::PF_R);
1482   return load_seg;
1483 }
1484
1485 // Save states of all current output segments.  Store saved states
1486 // in SEGMENT_STATES.
1487
1488 void
1489 Layout::save_segments(Segment_states* segment_states)
1490 {
1491   for (Segment_list::const_iterator p = this->segment_list_.begin();
1492        p != this->segment_list_.end();
1493        ++p)
1494     {
1495       Output_segment* segment = *p;
1496       // Shallow copy.
1497       Output_segment* copy = new Output_segment(*segment);
1498       (*segment_states)[segment] = copy;
1499     }
1500 }
1501
1502 // Restore states of output segments and delete any segment not found in
1503 // SEGMENT_STATES.
1504
1505 void
1506 Layout::restore_segments(const Segment_states* segment_states)
1507 {
1508   // Go through the segment list and remove any segment added in the
1509   // relaxation loop.
1510   this->tls_segment_ = NULL;
1511   this->relro_segment_ = NULL;
1512   Segment_list::iterator list_iter = this->segment_list_.begin();
1513   while (list_iter != this->segment_list_.end())
1514     {
1515       Output_segment* segment = *list_iter;
1516       Segment_states::const_iterator states_iter =
1517           segment_states->find(segment);
1518       if (states_iter != segment_states->end())
1519         {
1520           const Output_segment* copy = states_iter->second;
1521           // Shallow copy to restore states.
1522           *segment = *copy;
1523
1524           // Also fix up TLS and RELRO segment pointers as appropriate.
1525           if (segment->type() == elfcpp::PT_TLS)
1526             this->tls_segment_ = segment;
1527           else if (segment->type() == elfcpp::PT_GNU_RELRO)
1528             this->relro_segment_ = segment;
1529
1530           ++list_iter;
1531         }
1532       else
1533         {
1534           list_iter = this->segment_list_.erase(list_iter);
1535           // This is a segment created during section layout.  It should be
1536           // safe to remove it since we should have removed all pointers to it.
1537           delete segment;
1538         }
1539     }
1540 }
1541
1542 // Clean up after relaxation so that sections can be laid out again.
1543
1544 void
1545 Layout::clean_up_after_relaxation()
1546 {
1547   // Restore the segments to point state just prior to the relaxation loop.
1548   Script_sections* script_section = this->script_options_->script_sections();
1549   script_section->release_segments();
1550   this->restore_segments(this->segment_states_);
1551
1552   // Reset section addresses and file offsets
1553   for (Section_list::iterator p = this->section_list_.begin();
1554        p != this->section_list_.end();
1555        ++p)
1556     {
1557       (*p)->restore_states();
1558
1559       // If an input section changes size because of relaxation,
1560       // we need to adjust the section offsets of all input sections.
1561       // after such a section.
1562       if ((*p)->section_offsets_need_adjustment())
1563         (*p)->adjust_section_offsets();
1564
1565       (*p)->reset_address_and_file_offset();
1566     }
1567
1568   // Reset special output object address and file offsets.
1569   for (Data_list::iterator p = this->special_output_list_.begin();
1570        p != this->special_output_list_.end();
1571        ++p)
1572     (*p)->reset_address_and_file_offset();
1573
1574   // A linker script may have created some output section data objects.
1575   // They are useless now.
1576   for (Output_section_data_list::const_iterator p =
1577          this->script_output_section_data_list_.begin();
1578        p != this->script_output_section_data_list_.end();
1579        ++p)
1580     delete *p;
1581   this->script_output_section_data_list_.clear();
1582 }
1583
1584 // Prepare for relaxation.
1585
1586 void
1587 Layout::prepare_for_relaxation()
1588 {
1589   // Create an relaxation debug check if in debugging mode.
1590   if (is_debugging_enabled(DEBUG_RELAXATION))
1591     this->relaxation_debug_check_ = new Relaxation_debug_check();
1592
1593   // Save segment states.
1594   this->segment_states_ = new Segment_states();
1595   this->save_segments(this->segment_states_);
1596
1597   for(Section_list::const_iterator p = this->section_list_.begin();
1598       p != this->section_list_.end();
1599       ++p)
1600     (*p)->save_states();
1601
1602   if (is_debugging_enabled(DEBUG_RELAXATION))
1603     this->relaxation_debug_check_->check_output_data_for_reset_values(
1604         this->section_list_, this->special_output_list_);
1605
1606   // Also enable recording of output section data from scripts.
1607   this->record_output_section_data_from_script_ = true;
1608 }
1609
1610 // Relaxation loop body:  If target has no relaxation, this runs only once
1611 // Otherwise, the target relaxation hook is called at the end of
1612 // each iteration.  If the hook returns true, it means re-layout of
1613 // section is required.
1614 //
1615 // The number of segments created by a linking script without a PHDRS
1616 // clause may be affected by section sizes and alignments.  There is
1617 // a remote chance that relaxation causes different number of PT_LOAD
1618 // segments are created and sections are attached to different segments.
1619 // Therefore, we always throw away all segments created during section
1620 // layout.  In order to be able to restart the section layout, we keep
1621 // a copy of the segment list right before the relaxation loop and use
1622 // that to restore the segments.
1623 //
1624 // PASS is the current relaxation pass number.
1625 // SYMTAB is a symbol table.
1626 // PLOAD_SEG is the address of a pointer for the load segment.
1627 // PHDR_SEG is a pointer to the PHDR segment.
1628 // SEGMENT_HEADERS points to the output segment header.
1629 // FILE_HEADER points to the output file header.
1630 // PSHNDX is the address to store the output section index.
1631
1632 off_t inline
1633 Layout::relaxation_loop_body(
1634     int pass,
1635     Target* target,
1636     Symbol_table* symtab,
1637     Output_segment** pload_seg,
1638     Output_segment* phdr_seg,
1639     Output_segment_headers* segment_headers,
1640     Output_file_header* file_header,
1641     unsigned int* pshndx)
1642 {
1643   // If this is not the first iteration, we need to clean up after
1644   // relaxation so that we can lay out the sections again.
1645   if (pass != 0)
1646     this->clean_up_after_relaxation();
1647
1648   // If there is a SECTIONS clause, put all the input sections into
1649   // the required order.
1650   Output_segment* load_seg;
1651   if (this->script_options_->saw_sections_clause())
1652     load_seg = this->set_section_addresses_from_script(symtab);
1653   else if (parameters->options().relocatable())
1654     load_seg = NULL;
1655   else
1656     load_seg = this->find_first_load_seg();
1657
1658   if (parameters->options().oformat_enum()
1659       != General_options::OBJECT_FORMAT_ELF)
1660     load_seg = NULL;
1661
1662   // If the user set the address of the text segment, that may not be
1663   // compatible with putting the segment headers and file headers into
1664   // that segment.
1665   if (parameters->options().user_set_Ttext())
1666     load_seg = NULL;
1667
1668   gold_assert(phdr_seg == NULL
1669               || load_seg != NULL
1670               || this->script_options_->saw_sections_clause());
1671
1672   // If the address of the load segment we found has been set by
1673   // --section-start rather than by a script, then adjust the VMA and
1674   // LMA downward if possible to include the file and section headers.
1675   uint64_t header_gap = 0;
1676   if (load_seg != NULL
1677       && load_seg->are_addresses_set()
1678       && !this->script_options_->saw_sections_clause()
1679       && !parameters->options().relocatable())
1680     {
1681       file_header->finalize_data_size();
1682       segment_headers->finalize_data_size();
1683       size_t sizeof_headers = (file_header->data_size()
1684                                + segment_headers->data_size());
1685       const uint64_t abi_pagesize = target->abi_pagesize();
1686       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
1687       hdr_paddr &= ~(abi_pagesize - 1);
1688       uint64_t subtract = load_seg->paddr() - hdr_paddr;
1689       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
1690         load_seg = NULL;
1691       else
1692         {
1693           load_seg->set_addresses(load_seg->vaddr() - subtract,
1694                                   load_seg->paddr() - subtract);
1695           header_gap = subtract - sizeof_headers;
1696         }
1697     }
1698
1699   // Lay out the segment headers.
1700   if (!parameters->options().relocatable())
1701     {
1702       gold_assert(segment_headers != NULL);
1703       if (header_gap != 0 && load_seg != NULL)
1704         {
1705           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
1706           load_seg->add_initial_output_data(z);
1707         }
1708       if (load_seg != NULL)
1709         load_seg->add_initial_output_data(segment_headers);
1710       if (phdr_seg != NULL)
1711         phdr_seg->add_initial_output_data(segment_headers);
1712     }
1713
1714   // Lay out the file header.
1715   if (load_seg != NULL)
1716     load_seg->add_initial_output_data(file_header);
1717
1718   if (this->script_options_->saw_phdrs_clause()
1719       && !parameters->options().relocatable())
1720     {
1721       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1722       // clause in a linker script.
1723       Script_sections* ss = this->script_options_->script_sections();
1724       ss->put_headers_in_phdrs(file_header, segment_headers);
1725     }
1726
1727   // We set the output section indexes in set_segment_offsets and
1728   // set_section_indexes.
1729   *pshndx = 1;
1730
1731   // Set the file offsets of all the segments, and all the sections
1732   // they contain.
1733   off_t off;
1734   if (!parameters->options().relocatable())
1735     off = this->set_segment_offsets(target, load_seg, pshndx);
1736   else
1737     off = this->set_relocatable_section_offsets(file_header, pshndx);
1738
1739    // Verify that the dummy relaxation does not change anything.
1740   if (is_debugging_enabled(DEBUG_RELAXATION))
1741     {
1742       if (pass == 0)
1743         this->relaxation_debug_check_->read_sections(this->section_list_);
1744       else
1745         this->relaxation_debug_check_->verify_sections(this->section_list_);
1746     }
1747
1748   *pload_seg = load_seg;
1749   return off;
1750 }
1751
1752 // Search the list of patterns and find the postion of the given section
1753 // name in the output section.  If the section name matches a glob
1754 // pattern and a non-glob name, then the non-glob position takes
1755 // precedence.  Return 0 if no match is found.
1756
1757 unsigned int
1758 Layout::find_section_order_index(const std::string& section_name)
1759 {
1760   Unordered_map<std::string, unsigned int>::iterator map_it;
1761   map_it = this->input_section_position_.find(section_name);
1762   if (map_it != this->input_section_position_.end())
1763     return map_it->second;
1764
1765   // Absolute match failed.  Linear search the glob patterns.
1766   std::vector<std::string>::iterator it;
1767   for (it = this->input_section_glob_.begin();
1768        it != this->input_section_glob_.end();
1769        ++it)
1770     {
1771        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
1772          {
1773            map_it = this->input_section_position_.find(*it);
1774            gold_assert(map_it != this->input_section_position_.end());
1775            return map_it->second;
1776          }
1777     }
1778   return 0;
1779 }
1780
1781 // Read the sequence of input sections from the file specified with
1782 // --section-ordering-file.
1783
1784 void
1785 Layout::read_layout_from_file()
1786 {
1787   const char* filename = parameters->options().section_ordering_file();
1788   std::ifstream in;
1789   std::string line;
1790
1791   in.open(filename);
1792   if (!in)
1793     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
1794                filename, strerror(errno));
1795
1796   std::getline(in, line);   // this chops off the trailing \n, if any
1797   unsigned int position = 1;
1798
1799   while (in)
1800     {
1801       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
1802         line.resize(line.length() - 1);
1803       // Ignore comments, beginning with '#'
1804       if (line[0] == '#')
1805         {
1806           std::getline(in, line);
1807           continue;
1808         }
1809       this->input_section_position_[line] = position;
1810       // Store all glob patterns in a vector.
1811       if (is_wildcard_string(line.c_str()))
1812         this->input_section_glob_.push_back(line);
1813       position++;
1814       std::getline(in, line);
1815     }
1816 }
1817
1818 // Finalize the layout.  When this is called, we have created all the
1819 // output sections and all the output segments which are based on
1820 // input sections.  We have several things to do, and we have to do
1821 // them in the right order, so that we get the right results correctly
1822 // and efficiently.
1823
1824 // 1) Finalize the list of output segments and create the segment
1825 // table header.
1826
1827 // 2) Finalize the dynamic symbol table and associated sections.
1828
1829 // 3) Determine the final file offset of all the output segments.
1830
1831 // 4) Determine the final file offset of all the SHF_ALLOC output
1832 // sections.
1833
1834 // 5) Create the symbol table sections and the section name table
1835 // section.
1836
1837 // 6) Finalize the symbol table: set symbol values to their final
1838 // value and make a final determination of which symbols are going
1839 // into the output symbol table.
1840
1841 // 7) Create the section table header.
1842
1843 // 8) Determine the final file offset of all the output sections which
1844 // are not SHF_ALLOC, including the section table header.
1845
1846 // 9) Finalize the ELF file header.
1847
1848 // This function returns the size of the output file.
1849
1850 off_t
1851 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
1852                  Target* target, const Task* task)
1853 {
1854   target->finalize_sections(this, input_objects, symtab);
1855
1856   this->count_local_symbols(task, input_objects);
1857
1858   this->link_stabs_sections();
1859
1860   Output_segment* phdr_seg = NULL;
1861   if (!parameters->options().relocatable() && !parameters->doing_static_link())
1862     {
1863       // There was a dynamic object in the link.  We need to create
1864       // some information for the dynamic linker.
1865
1866       // Create the PT_PHDR segment which will hold the program
1867       // headers.
1868       if (!this->script_options_->saw_phdrs_clause())
1869         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
1870
1871       // Create the dynamic symbol table, including the hash table.
1872       Output_section* dynstr;
1873       std::vector<Symbol*> dynamic_symbols;
1874       unsigned int local_dynamic_count;
1875       Versions versions(*this->script_options()->version_script_info(),
1876                         &this->dynpool_);
1877       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
1878                                   &local_dynamic_count, &dynamic_symbols,
1879                                   &versions);
1880
1881       // Create the .interp section to hold the name of the
1882       // interpreter, and put it in a PT_INTERP segment.
1883       if (!parameters->options().shared())
1884         this->create_interp(target);
1885
1886       // Finish the .dynamic section to hold the dynamic data, and put
1887       // it in a PT_DYNAMIC segment.
1888       this->finish_dynamic_section(input_objects, symtab);
1889
1890       // We should have added everything we need to the dynamic string
1891       // table.
1892       this->dynpool_.set_string_offsets();
1893
1894       // Create the version sections.  We can't do this until the
1895       // dynamic string table is complete.
1896       this->create_version_sections(&versions, symtab, local_dynamic_count,
1897                                     dynamic_symbols, dynstr);
1898
1899       // Set the size of the _DYNAMIC symbol.  We can't do this until
1900       // after we call create_version_sections.
1901       this->set_dynamic_symbol_size(symtab);
1902     }
1903
1904   // Create segment headers.
1905   Output_segment_headers* segment_headers =
1906     (parameters->options().relocatable()
1907      ? NULL
1908      : new Output_segment_headers(this->segment_list_));
1909
1910   // Lay out the file header.
1911   Output_file_header* file_header
1912     = new Output_file_header(target, symtab, segment_headers,
1913                              parameters->options().entry());
1914
1915   this->special_output_list_.push_back(file_header);
1916   if (segment_headers != NULL)
1917     this->special_output_list_.push_back(segment_headers);
1918
1919   // Find approriate places for orphan output sections if we are using
1920   // a linker script.
1921   if (this->script_options_->saw_sections_clause())
1922     this->place_orphan_sections_in_script();
1923
1924   Output_segment* load_seg;
1925   off_t off;
1926   unsigned int shndx;
1927   int pass = 0;
1928
1929   // Take a snapshot of the section layout as needed.
1930   if (target->may_relax())
1931     this->prepare_for_relaxation();
1932
1933   // Run the relaxation loop to lay out sections.
1934   do
1935     {
1936       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
1937                                        phdr_seg, segment_headers, file_header,
1938                                        &shndx);
1939       pass++;
1940     }
1941   while (target->may_relax()
1942          && target->relax(pass, input_objects, symtab, this));
1943
1944   // Set the file offsets of all the non-data sections we've seen so
1945   // far which don't have to wait for the input sections.  We need
1946   // this in order to finalize local symbols in non-allocated
1947   // sections.
1948   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1949
1950   // Set the section indexes of all unallocated sections seen so far,
1951   // in case any of them are somehow referenced by a symbol.
1952   shndx = this->set_section_indexes(shndx);
1953
1954   // Create the symbol table sections.
1955   this->create_symtab_sections(input_objects, symtab, shndx, &off);
1956   if (!parameters->doing_static_link())
1957     this->assign_local_dynsym_offsets(input_objects);
1958
1959   // Process any symbol assignments from a linker script.  This must
1960   // be called after the symbol table has been finalized.
1961   this->script_options_->finalize_symbols(symtab, this);
1962
1963   // Create the incremental inputs sections.
1964   if (this->incremental_inputs_)
1965     {
1966       this->incremental_inputs_->finalize();
1967       this->create_incremental_info_sections(symtab);
1968     }
1969
1970   // Create the .shstrtab section.
1971   Output_section* shstrtab_section = this->create_shstrtab();
1972
1973   // Set the file offsets of the rest of the non-data sections which
1974   // don't have to wait for the input sections.
1975   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1976
1977   // Now that all sections have been created, set the section indexes
1978   // for any sections which haven't been done yet.
1979   shndx = this->set_section_indexes(shndx);
1980
1981   // Create the section table header.
1982   this->create_shdrs(shstrtab_section, &off);
1983
1984   // If there are no sections which require postprocessing, we can
1985   // handle the section names now, and avoid a resize later.
1986   if (!this->any_postprocessing_sections_)
1987     {
1988       off = this->set_section_offsets(off,
1989                                       POSTPROCESSING_SECTIONS_PASS);
1990       off =
1991           this->set_section_offsets(off,
1992                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1993     }
1994
1995   file_header->set_section_info(this->section_headers_, shstrtab_section);
1996
1997   // Now we know exactly where everything goes in the output file
1998   // (except for non-allocated sections which require postprocessing).
1999   Output_data::layout_complete();
2000
2001   this->output_file_size_ = off;
2002
2003   return off;
2004 }
2005
2006 // Create a note header following the format defined in the ELF ABI.
2007 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2008 // of the section to create, DESCSZ is the size of the descriptor.
2009 // ALLOCATE is true if the section should be allocated in memory.
2010 // This returns the new note section.  It sets *TRAILING_PADDING to
2011 // the number of trailing zero bytes required.
2012
2013 Output_section*
2014 Layout::create_note(const char* name, int note_type,
2015                     const char* section_name, size_t descsz,
2016                     bool allocate, size_t* trailing_padding)
2017 {
2018   // Authorities all agree that the values in a .note field should
2019   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
2020   // they differ on what the alignment is for 64-bit binaries.
2021   // The GABI says unambiguously they take 8-byte alignment:
2022   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2023   // Other documentation says alignment should always be 4 bytes:
2024   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2025   // GNU ld and GNU readelf both support the latter (at least as of
2026   // version 2.16.91), and glibc always generates the latter for
2027   // .note.ABI-tag (as of version 1.6), so that's the one we go with
2028   // here.
2029 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
2030   const int size = parameters->target().get_size();
2031 #else
2032   const int size = 32;
2033 #endif
2034
2035   // The contents of the .note section.
2036   size_t namesz = strlen(name) + 1;
2037   size_t aligned_namesz = align_address(namesz, size / 8);
2038   size_t aligned_descsz = align_address(descsz, size / 8);
2039
2040   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2041
2042   unsigned char* buffer = new unsigned char[notehdrsz];
2043   memset(buffer, 0, notehdrsz);
2044
2045   bool is_big_endian = parameters->target().is_big_endian();
2046
2047   if (size == 32)
2048     {
2049       if (!is_big_endian)
2050         {
2051           elfcpp::Swap<32, false>::writeval(buffer, namesz);
2052           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2053           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2054         }
2055       else
2056         {
2057           elfcpp::Swap<32, true>::writeval(buffer, namesz);
2058           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2059           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2060         }
2061     }
2062   else if (size == 64)
2063     {
2064       if (!is_big_endian)
2065         {
2066           elfcpp::Swap<64, false>::writeval(buffer, namesz);
2067           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2068           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2069         }
2070       else
2071         {
2072           elfcpp::Swap<64, true>::writeval(buffer, namesz);
2073           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2074           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2075         }
2076     }
2077   else
2078     gold_unreachable();
2079
2080   memcpy(buffer + 3 * (size / 8), name, namesz);
2081
2082   elfcpp::Elf_Xword flags = 0;
2083   Output_section_order order = ORDER_INVALID;
2084   if (allocate)
2085     {
2086       flags = elfcpp::SHF_ALLOC;
2087       order = ORDER_RO_NOTE;
2088     }
2089   Output_section* os = this->choose_output_section(NULL, section_name,
2090                                                    elfcpp::SHT_NOTE,
2091                                                    flags, false, order, false);
2092   if (os == NULL)
2093     return NULL;
2094
2095   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2096                                                            size / 8,
2097                                                            "** note header");
2098   os->add_output_section_data(posd);
2099
2100   *trailing_padding = aligned_descsz - descsz;
2101
2102   return os;
2103 }
2104
2105 // For an executable or shared library, create a note to record the
2106 // version of gold used to create the binary.
2107
2108 void
2109 Layout::create_gold_note()
2110 {
2111   if (parameters->options().relocatable())
2112     return;
2113
2114   std::string desc = std::string("gold ") + gold::get_version_string();
2115
2116   size_t trailing_padding;
2117   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2118                                          ".note.gnu.gold-version", desc.size(),
2119                                          false, &trailing_padding);
2120   if (os == NULL)
2121     return;
2122
2123   Output_section_data* posd = new Output_data_const(desc, 4);
2124   os->add_output_section_data(posd);
2125
2126   if (trailing_padding > 0)
2127     {
2128       posd = new Output_data_zero_fill(trailing_padding, 0);
2129       os->add_output_section_data(posd);
2130     }
2131 }
2132
2133 // Record whether the stack should be executable.  This can be set
2134 // from the command line using the -z execstack or -z noexecstack
2135 // options.  Otherwise, if any input file has a .note.GNU-stack
2136 // section with the SHF_EXECINSTR flag set, the stack should be
2137 // executable.  Otherwise, if at least one input file a
2138 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2139 // section, we use the target default for whether the stack should be
2140 // executable.  Otherwise, we don't generate a stack note.  When
2141 // generating a object file, we create a .note.GNU-stack section with
2142 // the appropriate marking.  When generating an executable or shared
2143 // library, we create a PT_GNU_STACK segment.
2144
2145 void
2146 Layout::create_executable_stack_info()
2147 {
2148   bool is_stack_executable;
2149   if (parameters->options().is_execstack_set())
2150     is_stack_executable = parameters->options().is_stack_executable();
2151   else if (!this->input_with_gnu_stack_note_)
2152     return;
2153   else
2154     {
2155       if (this->input_requires_executable_stack_)
2156         is_stack_executable = true;
2157       else if (this->input_without_gnu_stack_note_)
2158         is_stack_executable =
2159           parameters->target().is_default_stack_executable();
2160       else
2161         is_stack_executable = false;
2162     }
2163
2164   if (parameters->options().relocatable())
2165     {
2166       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2167       elfcpp::Elf_Xword flags = 0;
2168       if (is_stack_executable)
2169         flags |= elfcpp::SHF_EXECINSTR;
2170       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2171                                 ORDER_INVALID, false);
2172     }
2173   else
2174     {
2175       if (this->script_options_->saw_phdrs_clause())
2176         return;
2177       int flags = elfcpp::PF_R | elfcpp::PF_W;
2178       if (is_stack_executable)
2179         flags |= elfcpp::PF_X;
2180       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2181     }
2182 }
2183
2184 // If --build-id was used, set up the build ID note.
2185
2186 void
2187 Layout::create_build_id()
2188 {
2189   if (!parameters->options().user_set_build_id())
2190     return;
2191
2192   const char* style = parameters->options().build_id();
2193   if (strcmp(style, "none") == 0)
2194     return;
2195
2196   // Set DESCSZ to the size of the note descriptor.  When possible,
2197   // set DESC to the note descriptor contents.
2198   size_t descsz;
2199   std::string desc;
2200   if (strcmp(style, "md5") == 0)
2201     descsz = 128 / 8;
2202   else if (strcmp(style, "sha1") == 0)
2203     descsz = 160 / 8;
2204   else if (strcmp(style, "uuid") == 0)
2205     {
2206       const size_t uuidsz = 128 / 8;
2207
2208       char buffer[uuidsz];
2209       memset(buffer, 0, uuidsz);
2210
2211       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2212       if (descriptor < 0)
2213         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2214                    strerror(errno));
2215       else
2216         {
2217           ssize_t got = ::read(descriptor, buffer, uuidsz);
2218           release_descriptor(descriptor, true);
2219           if (got < 0)
2220             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2221           else if (static_cast<size_t>(got) != uuidsz)
2222             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2223                        uuidsz, got);
2224         }
2225
2226       desc.assign(buffer, uuidsz);
2227       descsz = uuidsz;
2228     }
2229   else if (strncmp(style, "0x", 2) == 0)
2230     {
2231       hex_init();
2232       const char* p = style + 2;
2233       while (*p != '\0')
2234         {
2235           if (hex_p(p[0]) && hex_p(p[1]))
2236             {
2237               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2238               desc += c;
2239               p += 2;
2240             }
2241           else if (*p == '-' || *p == ':')
2242             ++p;
2243           else
2244             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2245                        style);
2246         }
2247       descsz = desc.size();
2248     }
2249   else
2250     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2251
2252   // Create the note.
2253   size_t trailing_padding;
2254   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2255                                          ".note.gnu.build-id", descsz, true,
2256                                          &trailing_padding);
2257   if (os == NULL)
2258     return;
2259
2260   if (!desc.empty())
2261     {
2262       // We know the value already, so we fill it in now.
2263       gold_assert(desc.size() == descsz);
2264
2265       Output_section_data* posd = new Output_data_const(desc, 4);
2266       os->add_output_section_data(posd);
2267
2268       if (trailing_padding != 0)
2269         {
2270           posd = new Output_data_zero_fill(trailing_padding, 0);
2271           os->add_output_section_data(posd);
2272         }
2273     }
2274   else
2275     {
2276       // We need to compute a checksum after we have completed the
2277       // link.
2278       gold_assert(trailing_padding == 0);
2279       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2280       os->add_output_section_data(this->build_id_note_);
2281     }
2282 }
2283
2284 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2285 // field of the former should point to the latter.  I'm not sure who
2286 // started this, but the GNU linker does it, and some tools depend
2287 // upon it.
2288
2289 void
2290 Layout::link_stabs_sections()
2291 {
2292   if (!this->have_stabstr_section_)
2293     return;
2294
2295   for (Section_list::iterator p = this->section_list_.begin();
2296        p != this->section_list_.end();
2297        ++p)
2298     {
2299       if ((*p)->type() != elfcpp::SHT_STRTAB)
2300         continue;
2301
2302       const char* name = (*p)->name();
2303       if (strncmp(name, ".stab", 5) != 0)
2304         continue;
2305
2306       size_t len = strlen(name);
2307       if (strcmp(name + len - 3, "str") != 0)
2308         continue;
2309
2310       std::string stab_name(name, len - 3);
2311       Output_section* stab_sec;
2312       stab_sec = this->find_output_section(stab_name.c_str());
2313       if (stab_sec != NULL)
2314         stab_sec->set_link_section(*p);
2315     }
2316 }
2317
2318 // Create .gnu_incremental_inputs and related sections needed
2319 // for the next run of incremental linking to check what has changed.
2320
2321 void
2322 Layout::create_incremental_info_sections(Symbol_table* symtab)
2323 {
2324   Incremental_inputs* incr = this->incremental_inputs_;
2325
2326   gold_assert(incr != NULL);
2327
2328   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2329   incr->create_data_sections(symtab);
2330
2331   // Add the .gnu_incremental_inputs section.
2332   const char* incremental_inputs_name =
2333     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2334   Output_section* incremental_inputs_os =
2335     this->make_output_section(incremental_inputs_name,
2336                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2337                               ORDER_INVALID, false);
2338   incremental_inputs_os->add_output_section_data(incr->inputs_section());
2339
2340   // Add the .gnu_incremental_symtab section.
2341   const char* incremental_symtab_name =
2342     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2343   Output_section* incremental_symtab_os =
2344     this->make_output_section(incremental_symtab_name,
2345                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2346                               ORDER_INVALID, false);
2347   incremental_symtab_os->add_output_section_data(incr->symtab_section());
2348   incremental_symtab_os->set_entsize(4);
2349
2350   // Add the .gnu_incremental_relocs section.
2351   const char* incremental_relocs_name =
2352     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2353   Output_section* incremental_relocs_os =
2354     this->make_output_section(incremental_relocs_name,
2355                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2356                               ORDER_INVALID, false);
2357   incremental_relocs_os->add_output_section_data(incr->relocs_section());
2358   incremental_relocs_os->set_entsize(incr->relocs_entsize());
2359
2360   // Add the .gnu_incremental_got_plt section.
2361   const char* incremental_got_plt_name =
2362     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2363   Output_section* incremental_got_plt_os =
2364     this->make_output_section(incremental_got_plt_name,
2365                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2366                               ORDER_INVALID, false);
2367   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2368
2369   // Add the .gnu_incremental_strtab section.
2370   const char* incremental_strtab_name =
2371     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2372   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2373                                                         elfcpp::SHT_STRTAB, 0,
2374                                                         ORDER_INVALID, false);
2375   Output_data_strtab* strtab_data =
2376       new Output_data_strtab(incr->get_stringpool());
2377   incremental_strtab_os->add_output_section_data(strtab_data);
2378
2379   incremental_inputs_os->set_after_input_sections();
2380   incremental_symtab_os->set_after_input_sections();
2381   incremental_relocs_os->set_after_input_sections();
2382   incremental_got_plt_os->set_after_input_sections();
2383
2384   incremental_inputs_os->set_link_section(incremental_strtab_os);
2385   incremental_symtab_os->set_link_section(incremental_inputs_os);
2386   incremental_relocs_os->set_link_section(incremental_inputs_os);
2387   incremental_got_plt_os->set_link_section(incremental_inputs_os);
2388 }
2389
2390 // Return whether SEG1 should be before SEG2 in the output file.  This
2391 // is based entirely on the segment type and flags.  When this is
2392 // called the segment addresses has normally not yet been set.
2393
2394 bool
2395 Layout::segment_precedes(const Output_segment* seg1,
2396                          const Output_segment* seg2)
2397 {
2398   elfcpp::Elf_Word type1 = seg1->type();
2399   elfcpp::Elf_Word type2 = seg2->type();
2400
2401   // The single PT_PHDR segment is required to precede any loadable
2402   // segment.  We simply make it always first.
2403   if (type1 == elfcpp::PT_PHDR)
2404     {
2405       gold_assert(type2 != elfcpp::PT_PHDR);
2406       return true;
2407     }
2408   if (type2 == elfcpp::PT_PHDR)
2409     return false;
2410
2411   // The single PT_INTERP segment is required to precede any loadable
2412   // segment.  We simply make it always second.
2413   if (type1 == elfcpp::PT_INTERP)
2414     {
2415       gold_assert(type2 != elfcpp::PT_INTERP);
2416       return true;
2417     }
2418   if (type2 == elfcpp::PT_INTERP)
2419     return false;
2420
2421   // We then put PT_LOAD segments before any other segments.
2422   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2423     return true;
2424   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2425     return false;
2426
2427   // We put the PT_TLS segment last except for the PT_GNU_RELRO
2428   // segment, because that is where the dynamic linker expects to find
2429   // it (this is just for efficiency; other positions would also work
2430   // correctly).
2431   if (type1 == elfcpp::PT_TLS
2432       && type2 != elfcpp::PT_TLS
2433       && type2 != elfcpp::PT_GNU_RELRO)
2434     return false;
2435   if (type2 == elfcpp::PT_TLS
2436       && type1 != elfcpp::PT_TLS
2437       && type1 != elfcpp::PT_GNU_RELRO)
2438     return true;
2439
2440   // We put the PT_GNU_RELRO segment last, because that is where the
2441   // dynamic linker expects to find it (as with PT_TLS, this is just
2442   // for efficiency).
2443   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2444     return false;
2445   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2446     return true;
2447
2448   const elfcpp::Elf_Word flags1 = seg1->flags();
2449   const elfcpp::Elf_Word flags2 = seg2->flags();
2450
2451   // The order of non-PT_LOAD segments is unimportant.  We simply sort
2452   // by the numeric segment type and flags values.  There should not
2453   // be more than one segment with the same type and flags.
2454   if (type1 != elfcpp::PT_LOAD)
2455     {
2456       if (type1 != type2)
2457         return type1 < type2;
2458       gold_assert(flags1 != flags2);
2459       return flags1 < flags2;
2460     }
2461
2462   // If the addresses are set already, sort by load address.
2463   if (seg1->are_addresses_set())
2464     {
2465       if (!seg2->are_addresses_set())
2466         return true;
2467
2468       unsigned int section_count1 = seg1->output_section_count();
2469       unsigned int section_count2 = seg2->output_section_count();
2470       if (section_count1 == 0 && section_count2 > 0)
2471         return true;
2472       if (section_count1 > 0 && section_count2 == 0)
2473         return false;
2474
2475       uint64_t paddr1 = (seg1->are_addresses_set()
2476                          ? seg1->paddr()
2477                          : seg1->first_section_load_address());
2478       uint64_t paddr2 = (seg2->are_addresses_set()
2479                          ? seg2->paddr()
2480                          : seg2->first_section_load_address());
2481
2482       if (paddr1 != paddr2)
2483         return paddr1 < paddr2;
2484     }
2485   else if (seg2->are_addresses_set())
2486     return false;
2487
2488   // A segment which holds large data comes after a segment which does
2489   // not hold large data.
2490   if (seg1->is_large_data_segment())
2491     {
2492       if (!seg2->is_large_data_segment())
2493         return false;
2494     }
2495   else if (seg2->is_large_data_segment())
2496     return true;
2497
2498   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
2499   // segments come before writable segments.  Then writable segments
2500   // with data come before writable segments without data.  Then
2501   // executable segments come before non-executable segments.  Then
2502   // the unlikely case of a non-readable segment comes before the
2503   // normal case of a readable segment.  If there are multiple
2504   // segments with the same type and flags, we require that the
2505   // address be set, and we sort by virtual address and then physical
2506   // address.
2507   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2508     return (flags1 & elfcpp::PF_W) == 0;
2509   if ((flags1 & elfcpp::PF_W) != 0
2510       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2511     return seg1->has_any_data_sections();
2512   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2513     return (flags1 & elfcpp::PF_X) != 0;
2514   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2515     return (flags1 & elfcpp::PF_R) == 0;
2516
2517   // We shouldn't get here--we shouldn't create segments which we
2518   // can't distinguish.
2519   gold_unreachable();
2520 }
2521
2522 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2523
2524 static off_t
2525 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2526 {
2527   uint64_t unsigned_off = off;
2528   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2529                           | (addr & (abi_pagesize - 1)));
2530   if (aligned_off < unsigned_off)
2531     aligned_off += abi_pagesize;
2532   return aligned_off;
2533 }
2534
2535 // Set the file offsets of all the segments, and all the sections they
2536 // contain.  They have all been created.  LOAD_SEG must be be laid out
2537 // first.  Return the offset of the data to follow.
2538
2539 off_t
2540 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
2541                             unsigned int* pshndx)
2542 {
2543   // Sort them into the final order.
2544   std::sort(this->segment_list_.begin(), this->segment_list_.end(),
2545             Layout::Compare_segments());
2546
2547   // Find the PT_LOAD segments, and set their addresses and offsets
2548   // and their section's addresses and offsets.
2549   uint64_t addr;
2550   if (parameters->options().user_set_Ttext())
2551     addr = parameters->options().Ttext();
2552   else if (parameters->options().output_is_position_independent())
2553     addr = 0;
2554   else
2555     addr = target->default_text_segment_address();
2556   off_t off = 0;
2557
2558   // If LOAD_SEG is NULL, then the file header and segment headers
2559   // will not be loadable.  But they still need to be at offset 0 in
2560   // the file.  Set their offsets now.
2561   if (load_seg == NULL)
2562     {
2563       for (Data_list::iterator p = this->special_output_list_.begin();
2564            p != this->special_output_list_.end();
2565            ++p)
2566         {
2567           off = align_address(off, (*p)->addralign());
2568           (*p)->set_address_and_file_offset(0, off);
2569           off += (*p)->data_size();
2570         }
2571     }
2572
2573   unsigned int increase_relro = this->increase_relro_;
2574   if (this->script_options_->saw_sections_clause())
2575     increase_relro = 0;
2576
2577   const bool check_sections = parameters->options().check_sections();
2578   Output_segment* last_load_segment = NULL;
2579
2580   for (Segment_list::iterator p = this->segment_list_.begin();
2581        p != this->segment_list_.end();
2582        ++p)
2583     {
2584       if ((*p)->type() == elfcpp::PT_LOAD)
2585         {
2586           if (load_seg != NULL && load_seg != *p)
2587             gold_unreachable();
2588           load_seg = NULL;
2589
2590           bool are_addresses_set = (*p)->are_addresses_set();
2591           if (are_addresses_set)
2592             {
2593               // When it comes to setting file offsets, we care about
2594               // the physical address.
2595               addr = (*p)->paddr();
2596             }
2597           else if (parameters->options().user_set_Tdata()
2598                    && ((*p)->flags() & elfcpp::PF_W) != 0
2599                    && (!parameters->options().user_set_Tbss()
2600                        || (*p)->has_any_data_sections()))
2601             {
2602               addr = parameters->options().Tdata();
2603               are_addresses_set = true;
2604             }
2605           else if (parameters->options().user_set_Tbss()
2606                    && ((*p)->flags() & elfcpp::PF_W) != 0
2607                    && !(*p)->has_any_data_sections())
2608             {
2609               addr = parameters->options().Tbss();
2610               are_addresses_set = true;
2611             }
2612
2613           uint64_t orig_addr = addr;
2614           uint64_t orig_off = off;
2615
2616           uint64_t aligned_addr = 0;
2617           uint64_t abi_pagesize = target->abi_pagesize();
2618           uint64_t common_pagesize = target->common_pagesize();
2619
2620           if (!parameters->options().nmagic()
2621               && !parameters->options().omagic())
2622             (*p)->set_minimum_p_align(common_pagesize);
2623
2624           if (!are_addresses_set)
2625             {
2626               // Skip the address forward one page, maintaining the same
2627               // position within the page.  This lets us store both segments
2628               // overlapping on a single page in the file, but the loader will
2629               // put them on different pages in memory. We will revisit this
2630               // decision once we know the size of the segment.
2631
2632               addr = align_address(addr, (*p)->maximum_alignment());
2633               aligned_addr = addr;
2634
2635               if ((addr & (abi_pagesize - 1)) != 0)
2636                 addr = addr + abi_pagesize;
2637
2638               off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2639             }
2640
2641           if (!parameters->options().nmagic()
2642               && !parameters->options().omagic())
2643             off = align_file_offset(off, addr, abi_pagesize);
2644           else if (load_seg == NULL)
2645             {
2646               // This is -N or -n with a section script which prevents
2647               // us from using a load segment.  We need to ensure that
2648               // the file offset is aligned to the alignment of the
2649               // segment.  This is because the linker script
2650               // implicitly assumed a zero offset.  If we don't align
2651               // here, then the alignment of the sections in the
2652               // linker script may not match the alignment of the
2653               // sections in the set_section_addresses call below,
2654               // causing an error about dot moving backward.
2655               off = align_address(off, (*p)->maximum_alignment());
2656             }
2657
2658           unsigned int shndx_hold = *pshndx;
2659           uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
2660                                                           increase_relro,
2661                                                           &off, pshndx);
2662
2663           // Now that we know the size of this segment, we may be able
2664           // to save a page in memory, at the cost of wasting some
2665           // file space, by instead aligning to the start of a new
2666           // page.  Here we use the real machine page size rather than
2667           // the ABI mandated page size.
2668
2669           if (!are_addresses_set && aligned_addr != addr)
2670             {
2671               uint64_t first_off = (common_pagesize
2672                                     - (aligned_addr
2673                                        & (common_pagesize - 1)));
2674               uint64_t last_off = new_addr & (common_pagesize - 1);
2675               if (first_off > 0
2676                   && last_off > 0
2677                   && ((aligned_addr & ~ (common_pagesize - 1))
2678                       != (new_addr & ~ (common_pagesize - 1)))
2679                   && first_off + last_off <= common_pagesize)
2680                 {
2681                   *pshndx = shndx_hold;
2682                   addr = align_address(aligned_addr, common_pagesize);
2683                   addr = align_address(addr, (*p)->maximum_alignment());
2684                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2685                   off = align_file_offset(off, addr, abi_pagesize);
2686                   new_addr = (*p)->set_section_addresses(this, true, addr,
2687                                                          increase_relro,
2688                                                          &off, pshndx);
2689                 }
2690             }
2691
2692           addr = new_addr;
2693
2694           // Implement --check-sections.  We know that the segments
2695           // are sorted by LMA.
2696           if (check_sections && last_load_segment != NULL)
2697             {
2698               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
2699               if (last_load_segment->paddr() + last_load_segment->memsz()
2700                   > (*p)->paddr())
2701                 {
2702                   unsigned long long lb1 = last_load_segment->paddr();
2703                   unsigned long long le1 = lb1 + last_load_segment->memsz();
2704                   unsigned long long lb2 = (*p)->paddr();
2705                   unsigned long long le2 = lb2 + (*p)->memsz();
2706                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2707                                "[0x%llx -> 0x%llx]"),
2708                              lb1, le1, lb2, le2);
2709                 }
2710             }
2711           last_load_segment = *p;
2712         }
2713     }
2714
2715   // Handle the non-PT_LOAD segments, setting their offsets from their
2716   // section's offsets.
2717   for (Segment_list::iterator p = this->segment_list_.begin();
2718        p != this->segment_list_.end();
2719        ++p)
2720     {
2721       if ((*p)->type() != elfcpp::PT_LOAD)
2722         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
2723                          ? increase_relro
2724                          : 0);
2725     }
2726
2727   // Set the TLS offsets for each section in the PT_TLS segment.
2728   if (this->tls_segment_ != NULL)
2729     this->tls_segment_->set_tls_offsets();
2730
2731   return off;
2732 }
2733
2734 // Set the offsets of all the allocated sections when doing a
2735 // relocatable link.  This does the same jobs as set_segment_offsets,
2736 // only for a relocatable link.
2737
2738 off_t
2739 Layout::set_relocatable_section_offsets(Output_data* file_header,
2740                                         unsigned int* pshndx)
2741 {
2742   off_t off = 0;
2743
2744   file_header->set_address_and_file_offset(0, 0);
2745   off += file_header->data_size();
2746
2747   for (Section_list::iterator p = this->section_list_.begin();
2748        p != this->section_list_.end();
2749        ++p)
2750     {
2751       // We skip unallocated sections here, except that group sections
2752       // have to come first.
2753       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
2754           && (*p)->type() != elfcpp::SHT_GROUP)
2755         continue;
2756
2757       off = align_address(off, (*p)->addralign());
2758
2759       // The linker script might have set the address.
2760       if (!(*p)->is_address_valid())
2761         (*p)->set_address(0);
2762       (*p)->set_file_offset(off);
2763       (*p)->finalize_data_size();
2764       off += (*p)->data_size();
2765
2766       (*p)->set_out_shndx(*pshndx);
2767       ++*pshndx;
2768     }
2769
2770   return off;
2771 }
2772
2773 // Set the file offset of all the sections not associated with a
2774 // segment.
2775
2776 off_t
2777 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
2778 {
2779   for (Section_list::iterator p = this->unattached_section_list_.begin();
2780        p != this->unattached_section_list_.end();
2781        ++p)
2782     {
2783       // The symtab section is handled in create_symtab_sections.
2784       if (*p == this->symtab_section_)
2785         continue;
2786
2787       // If we've already set the data size, don't set it again.
2788       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
2789         continue;
2790
2791       if (pass == BEFORE_INPUT_SECTIONS_PASS
2792           && (*p)->requires_postprocessing())
2793         {
2794           (*p)->create_postprocessing_buffer();
2795           this->any_postprocessing_sections_ = true;
2796         }
2797
2798       if (pass == BEFORE_INPUT_SECTIONS_PASS
2799           && (*p)->after_input_sections())
2800         continue;
2801       else if (pass == POSTPROCESSING_SECTIONS_PASS
2802                && (!(*p)->after_input_sections()
2803                    || (*p)->type() == elfcpp::SHT_STRTAB))
2804         continue;
2805       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
2806                && (!(*p)->after_input_sections()
2807                    || (*p)->type() != elfcpp::SHT_STRTAB))
2808         continue;
2809
2810       off = align_address(off, (*p)->addralign());
2811       (*p)->set_file_offset(off);
2812       (*p)->finalize_data_size();
2813       off += (*p)->data_size();
2814
2815       // At this point the name must be set.
2816       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
2817         this->namepool_.add((*p)->name(), false, NULL);
2818     }
2819   return off;
2820 }
2821
2822 // Set the section indexes of all the sections not associated with a
2823 // segment.
2824
2825 unsigned int
2826 Layout::set_section_indexes(unsigned int shndx)
2827 {
2828   for (Section_list::iterator p = this->unattached_section_list_.begin();
2829        p != this->unattached_section_list_.end();
2830        ++p)
2831     {
2832       if (!(*p)->has_out_shndx())
2833         {
2834           (*p)->set_out_shndx(shndx);
2835           ++shndx;
2836         }
2837     }
2838   return shndx;
2839 }
2840
2841 // Set the section addresses according to the linker script.  This is
2842 // only called when we see a SECTIONS clause.  This returns the
2843 // program segment which should hold the file header and segment
2844 // headers, if any.  It will return NULL if they should not be in a
2845 // segment.
2846
2847 Output_segment*
2848 Layout::set_section_addresses_from_script(Symbol_table* symtab)
2849 {
2850   Script_sections* ss = this->script_options_->script_sections();
2851   gold_assert(ss->saw_sections_clause());
2852   return this->script_options_->set_section_addresses(symtab, this);
2853 }
2854
2855 // Place the orphan sections in the linker script.
2856
2857 void
2858 Layout::place_orphan_sections_in_script()
2859 {
2860   Script_sections* ss = this->script_options_->script_sections();
2861   gold_assert(ss->saw_sections_clause());
2862
2863   // Place each orphaned output section in the script.
2864   for (Section_list::iterator p = this->section_list_.begin();
2865        p != this->section_list_.end();
2866        ++p)
2867     {
2868       if (!(*p)->found_in_sections_clause())
2869         ss->place_orphan(*p);
2870     }
2871 }
2872
2873 // Count the local symbols in the regular symbol table and the dynamic
2874 // symbol table, and build the respective string pools.
2875
2876 void
2877 Layout::count_local_symbols(const Task* task,
2878                             const Input_objects* input_objects)
2879 {
2880   // First, figure out an upper bound on the number of symbols we'll
2881   // be inserting into each pool.  This helps us create the pools with
2882   // the right size, to avoid unnecessary hashtable resizing.
2883   unsigned int symbol_count = 0;
2884   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2885        p != input_objects->relobj_end();
2886        ++p)
2887     symbol_count += (*p)->local_symbol_count();
2888
2889   // Go from "upper bound" to "estimate."  We overcount for two
2890   // reasons: we double-count symbols that occur in more than one
2891   // object file, and we count symbols that are dropped from the
2892   // output.  Add it all together and assume we overcount by 100%.
2893   symbol_count /= 2;
2894
2895   // We assume all symbols will go into both the sympool and dynpool.
2896   this->sympool_.reserve(symbol_count);
2897   this->dynpool_.reserve(symbol_count);
2898
2899   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2900        p != input_objects->relobj_end();
2901        ++p)
2902     {
2903       Task_lock_obj<Object> tlo(task, *p);
2904       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
2905     }
2906 }
2907
2908 // Create the symbol table sections.  Here we also set the final
2909 // values of the symbols.  At this point all the loadable sections are
2910 // fully laid out.  SHNUM is the number of sections so far.
2911
2912 void
2913 Layout::create_symtab_sections(const Input_objects* input_objects,
2914                                Symbol_table* symtab,
2915                                unsigned int shnum,
2916                                off_t* poff)
2917 {
2918   int symsize;
2919   unsigned int align;
2920   if (parameters->target().get_size() == 32)
2921     {
2922       symsize = elfcpp::Elf_sizes<32>::sym_size;
2923       align = 4;
2924     }
2925   else if (parameters->target().get_size() == 64)
2926     {
2927       symsize = elfcpp::Elf_sizes<64>::sym_size;
2928       align = 8;
2929     }
2930   else
2931     gold_unreachable();
2932
2933   off_t off = *poff;
2934   off = align_address(off, align);
2935   off_t startoff = off;
2936
2937   // Save space for the dummy symbol at the start of the section.  We
2938   // never bother to write this out--it will just be left as zero.
2939   off += symsize;
2940   unsigned int local_symbol_index = 1;
2941
2942   // Add STT_SECTION symbols for each Output section which needs one.
2943   for (Section_list::iterator p = this->section_list_.begin();
2944        p != this->section_list_.end();
2945        ++p)
2946     {
2947       if (!(*p)->needs_symtab_index())
2948         (*p)->set_symtab_index(-1U);
2949       else
2950         {
2951           (*p)->set_symtab_index(local_symbol_index);
2952           ++local_symbol_index;
2953           off += symsize;
2954         }
2955     }
2956
2957   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2958        p != input_objects->relobj_end();
2959        ++p)
2960     {
2961       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
2962                                                         off, symtab);
2963       off += (index - local_symbol_index) * symsize;
2964       local_symbol_index = index;
2965     }
2966
2967   unsigned int local_symcount = local_symbol_index;
2968   gold_assert(static_cast<off_t>(local_symcount * symsize) == off - startoff);
2969
2970   off_t dynoff;
2971   size_t dyn_global_index;
2972   size_t dyncount;
2973   if (this->dynsym_section_ == NULL)
2974     {
2975       dynoff = 0;
2976       dyn_global_index = 0;
2977       dyncount = 0;
2978     }
2979   else
2980     {
2981       dyn_global_index = this->dynsym_section_->info();
2982       off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
2983       dynoff = this->dynsym_section_->offset() + locsize;
2984       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
2985       gold_assert(static_cast<off_t>(dyncount * symsize)
2986                   == this->dynsym_section_->data_size() - locsize);
2987     }
2988
2989   off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
2990                          &this->sympool_, &local_symcount);
2991
2992   if (!parameters->options().strip_all())
2993     {
2994       this->sympool_.set_string_offsets();
2995
2996       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
2997       Output_section* osymtab = this->make_output_section(symtab_name,
2998                                                           elfcpp::SHT_SYMTAB,
2999                                                           0, ORDER_INVALID,
3000                                                           false);
3001       this->symtab_section_ = osymtab;
3002
3003       Output_section_data* pos = new Output_data_fixed_space(off - startoff,
3004                                                              align,
3005                                                              "** symtab");
3006       osymtab->add_output_section_data(pos);
3007
3008       // We generate a .symtab_shndx section if we have more than
3009       // SHN_LORESERVE sections.  Technically it is possible that we
3010       // don't need one, because it is possible that there are no
3011       // symbols in any of sections with indexes larger than
3012       // SHN_LORESERVE.  That is probably unusual, though, and it is
3013       // easier to always create one than to compute section indexes
3014       // twice (once here, once when writing out the symbols).
3015       if (shnum >= elfcpp::SHN_LORESERVE)
3016         {
3017           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3018                                                                false, NULL);
3019           Output_section* osymtab_xindex =
3020             this->make_output_section(symtab_xindex_name,
3021                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
3022                                       ORDER_INVALID, false);
3023
3024           size_t symcount = (off - startoff) / symsize;
3025           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3026
3027           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3028
3029           osymtab_xindex->set_link_section(osymtab);
3030           osymtab_xindex->set_addralign(4);
3031           osymtab_xindex->set_entsize(4);
3032
3033           osymtab_xindex->set_after_input_sections();
3034
3035           // This tells the driver code to wait until the symbol table
3036           // has written out before writing out the postprocessing
3037           // sections, including the .symtab_shndx section.
3038           this->any_postprocessing_sections_ = true;
3039         }
3040
3041       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3042       Output_section* ostrtab = this->make_output_section(strtab_name,
3043                                                           elfcpp::SHT_STRTAB,
3044                                                           0, ORDER_INVALID,
3045                                                           false);
3046
3047       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3048       ostrtab->add_output_section_data(pstr);
3049
3050       osymtab->set_file_offset(startoff);
3051       osymtab->finalize_data_size();
3052       osymtab->set_link_section(ostrtab);
3053       osymtab->set_info(local_symcount);
3054       osymtab->set_entsize(symsize);
3055
3056       *poff = off;
3057     }
3058 }
3059
3060 // Create the .shstrtab section, which holds the names of the
3061 // sections.  At the time this is called, we have created all the
3062 // output sections except .shstrtab itself.
3063
3064 Output_section*
3065 Layout::create_shstrtab()
3066 {
3067   // FIXME: We don't need to create a .shstrtab section if we are
3068   // stripping everything.
3069
3070   const char* name = this->namepool_.add(".shstrtab", false, NULL);
3071
3072   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3073                                                  ORDER_INVALID, false);
3074
3075   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3076     {
3077       // We can't write out this section until we've set all the
3078       // section names, and we don't set the names of compressed
3079       // output sections until relocations are complete.  FIXME: With
3080       // the current names we use, this is unnecessary.
3081       os->set_after_input_sections();
3082     }
3083
3084   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3085   os->add_output_section_data(posd);
3086
3087   return os;
3088 }
3089
3090 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
3091 // offset.
3092
3093 void
3094 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3095 {
3096   Output_section_headers* oshdrs;
3097   oshdrs = new Output_section_headers(this,
3098                                       &this->segment_list_,
3099                                       &this->section_list_,
3100                                       &this->unattached_section_list_,
3101                                       &this->namepool_,
3102                                       shstrtab_section);
3103   off_t off = align_address(*poff, oshdrs->addralign());
3104   oshdrs->set_address_and_file_offset(0, off);
3105   off += oshdrs->data_size();
3106   *poff = off;
3107   this->section_headers_ = oshdrs;
3108 }
3109
3110 // Count the allocated sections.
3111
3112 size_t
3113 Layout::allocated_output_section_count() const
3114 {
3115   size_t section_count = 0;
3116   for (Segment_list::const_iterator p = this->segment_list_.begin();
3117        p != this->segment_list_.end();
3118        ++p)
3119     section_count += (*p)->output_section_count();
3120   return section_count;
3121 }
3122
3123 // Create the dynamic symbol table.
3124
3125 void
3126 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3127                               Symbol_table* symtab,
3128                               Output_section** pdynstr,
3129                               unsigned int* plocal_dynamic_count,
3130                               std::vector<Symbol*>* pdynamic_symbols,
3131                               Versions* pversions)
3132 {
3133   // Count all the symbols in the dynamic symbol table, and set the
3134   // dynamic symbol indexes.
3135
3136   // Skip symbol 0, which is always all zeroes.
3137   unsigned int index = 1;
3138
3139   // Add STT_SECTION symbols for each Output section which needs one.
3140   for (Section_list::iterator p = this->section_list_.begin();
3141        p != this->section_list_.end();
3142        ++p)
3143     {
3144       if (!(*p)->needs_dynsym_index())
3145         (*p)->set_dynsym_index(-1U);
3146       else
3147         {
3148           (*p)->set_dynsym_index(index);
3149           ++index;
3150         }
3151     }
3152
3153   // Count the local symbols that need to go in the dynamic symbol table,
3154   // and set the dynamic symbol indexes.
3155   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3156        p != input_objects->relobj_end();
3157        ++p)
3158     {
3159       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3160       index = new_index;
3161     }
3162
3163   unsigned int local_symcount = index;
3164   *plocal_dynamic_count = local_symcount;
3165
3166   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3167                                      &this->dynpool_, pversions);
3168
3169   int symsize;
3170   unsigned int align;
3171   const int size = parameters->target().get_size();
3172   if (size == 32)
3173     {
3174       symsize = elfcpp::Elf_sizes<32>::sym_size;
3175       align = 4;
3176     }
3177   else if (size == 64)
3178     {
3179       symsize = elfcpp::Elf_sizes<64>::sym_size;
3180       align = 8;
3181     }
3182   else
3183     gold_unreachable();
3184
3185   // Create the dynamic symbol table section.
3186
3187   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3188                                                        elfcpp::SHT_DYNSYM,
3189                                                        elfcpp::SHF_ALLOC,
3190                                                        false,
3191                                                        ORDER_DYNAMIC_LINKER,
3192                                                        false);
3193
3194   Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3195                                                            align,
3196                                                            "** dynsym");
3197   dynsym->add_output_section_data(odata);
3198
3199   dynsym->set_info(local_symcount);
3200   dynsym->set_entsize(symsize);
3201   dynsym->set_addralign(align);
3202
3203   this->dynsym_section_ = dynsym;
3204
3205   Output_data_dynamic* const odyn = this->dynamic_data_;
3206   odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3207   odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3208
3209   // If there are more than SHN_LORESERVE allocated sections, we
3210   // create a .dynsym_shndx section.  It is possible that we don't
3211   // need one, because it is possible that there are no dynamic
3212   // symbols in any of the sections with indexes larger than
3213   // SHN_LORESERVE.  This is probably unusual, though, and at this
3214   // time we don't know the actual section indexes so it is
3215   // inconvenient to check.
3216   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3217     {
3218       Output_section* dynsym_xindex =
3219         this->choose_output_section(NULL, ".dynsym_shndx",
3220                                     elfcpp::SHT_SYMTAB_SHNDX,
3221                                     elfcpp::SHF_ALLOC,
3222                                     false, ORDER_DYNAMIC_LINKER, false);
3223
3224       this->dynsym_xindex_ = new Output_symtab_xindex(index);
3225
3226       dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3227
3228       dynsym_xindex->set_link_section(dynsym);
3229       dynsym_xindex->set_addralign(4);
3230       dynsym_xindex->set_entsize(4);
3231
3232       dynsym_xindex->set_after_input_sections();
3233
3234       // This tells the driver code to wait until the symbol table has
3235       // written out before writing out the postprocessing sections,
3236       // including the .dynsym_shndx section.
3237       this->any_postprocessing_sections_ = true;
3238     }
3239
3240   // Create the dynamic string table section.
3241
3242   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3243                                                        elfcpp::SHT_STRTAB,
3244                                                        elfcpp::SHF_ALLOC,
3245                                                        false,
3246                                                        ORDER_DYNAMIC_LINKER,
3247                                                        false);
3248
3249   Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3250   dynstr->add_output_section_data(strdata);
3251
3252   dynsym->set_link_section(dynstr);
3253   this->dynamic_section_->set_link_section(dynstr);
3254
3255   odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3256   odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3257
3258   *pdynstr = dynstr;
3259
3260   // Create the hash tables.
3261
3262   if (strcmp(parameters->options().hash_style(), "sysv") == 0
3263       || strcmp(parameters->options().hash_style(), "both") == 0)
3264     {
3265       unsigned char* phash;
3266       unsigned int hashlen;
3267       Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3268                                     &phash, &hashlen);
3269
3270       Output_section* hashsec =
3271         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3272                                     elfcpp::SHF_ALLOC, false,
3273                                     ORDER_DYNAMIC_LINKER, false);
3274
3275       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3276                                                                    hashlen,
3277                                                                    align,
3278                                                                    "** hash");
3279       hashsec->add_output_section_data(hashdata);
3280
3281       hashsec->set_link_section(dynsym);
3282       hashsec->set_entsize(4);
3283
3284       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3285     }
3286
3287   if (strcmp(parameters->options().hash_style(), "gnu") == 0
3288       || strcmp(parameters->options().hash_style(), "both") == 0)
3289     {
3290       unsigned char* phash;
3291       unsigned int hashlen;
3292       Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3293                                     &phash, &hashlen);
3294
3295       Output_section* hashsec =
3296         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3297                                     elfcpp::SHF_ALLOC, false,
3298                                     ORDER_DYNAMIC_LINKER, false);
3299
3300       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3301                                                                    hashlen,
3302                                                                    align,
3303                                                                    "** hash");
3304       hashsec->add_output_section_data(hashdata);
3305
3306       hashsec->set_link_section(dynsym);
3307
3308       // For a 64-bit target, the entries in .gnu.hash do not have a
3309       // uniform size, so we only set the entry size for a 32-bit
3310       // target.
3311       if (parameters->target().get_size() == 32)
3312         hashsec->set_entsize(4);
3313
3314       odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3315     }
3316 }
3317
3318 // Assign offsets to each local portion of the dynamic symbol table.
3319
3320 void
3321 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3322 {
3323   Output_section* dynsym = this->dynsym_section_;
3324   gold_assert(dynsym != NULL);
3325
3326   off_t off = dynsym->offset();
3327
3328   // Skip the dummy symbol at the start of the section.
3329   off += dynsym->entsize();
3330
3331   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3332        p != input_objects->relobj_end();
3333        ++p)
3334     {
3335       unsigned int count = (*p)->set_local_dynsym_offset(off);
3336       off += count * dynsym->entsize();
3337     }
3338 }
3339
3340 // Create the version sections.
3341
3342 void
3343 Layout::create_version_sections(const Versions* versions,
3344                                 const Symbol_table* symtab,
3345                                 unsigned int local_symcount,
3346                                 const std::vector<Symbol*>& dynamic_symbols,
3347                                 const Output_section* dynstr)
3348 {
3349   if (!versions->any_defs() && !versions->any_needs())
3350     return;
3351
3352   switch (parameters->size_and_endianness())
3353     {
3354 #ifdef HAVE_TARGET_32_LITTLE
3355     case Parameters::TARGET_32_LITTLE:
3356       this->sized_create_version_sections<32, false>(versions, symtab,
3357                                                      local_symcount,
3358                                                      dynamic_symbols, dynstr);
3359       break;
3360 #endif
3361 #ifdef HAVE_TARGET_32_BIG
3362     case Parameters::TARGET_32_BIG:
3363       this->sized_create_version_sections<32, true>(versions, symtab,
3364                                                     local_symcount,
3365                                                     dynamic_symbols, dynstr);
3366       break;
3367 #endif
3368 #ifdef HAVE_TARGET_64_LITTLE
3369     case Parameters::TARGET_64_LITTLE:
3370       this->sized_create_version_sections<64, false>(versions, symtab,
3371                                                      local_symcount,
3372                                                      dynamic_symbols, dynstr);
3373       break;
3374 #endif
3375 #ifdef HAVE_TARGET_64_BIG
3376     case Parameters::TARGET_64_BIG:
3377       this->sized_create_version_sections<64, true>(versions, symtab,
3378                                                     local_symcount,
3379                                                     dynamic_symbols, dynstr);
3380       break;
3381 #endif
3382     default:
3383       gold_unreachable();
3384     }
3385 }
3386
3387 // Create the version sections, sized version.
3388
3389 template<int size, bool big_endian>
3390 void
3391 Layout::sized_create_version_sections(
3392     const Versions* versions,
3393     const Symbol_table* symtab,
3394     unsigned int local_symcount,
3395     const std::vector<Symbol*>& dynamic_symbols,
3396     const Output_section* dynstr)
3397 {
3398   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3399                                                      elfcpp::SHT_GNU_versym,
3400                                                      elfcpp::SHF_ALLOC,
3401                                                      false,
3402                                                      ORDER_DYNAMIC_LINKER,
3403                                                      false);
3404
3405   unsigned char* vbuf;
3406   unsigned int vsize;
3407   versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
3408                                                       local_symcount,
3409                                                       dynamic_symbols,
3410                                                       &vbuf, &vsize);
3411
3412   Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
3413                                                             "** versions");
3414
3415   vsec->add_output_section_data(vdata);
3416   vsec->set_entsize(2);
3417   vsec->set_link_section(this->dynsym_section_);
3418
3419   Output_data_dynamic* const odyn = this->dynamic_data_;
3420   odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
3421
3422   if (versions->any_defs())
3423     {
3424       Output_section* vdsec;
3425       vdsec= this->choose_output_section(NULL, ".gnu.version_d",
3426                                          elfcpp::SHT_GNU_verdef,
3427                                          elfcpp::SHF_ALLOC,
3428                                          false, ORDER_DYNAMIC_LINKER, false);
3429
3430       unsigned char* vdbuf;
3431       unsigned int vdsize;
3432       unsigned int vdentries;
3433       versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
3434                                                        &vdsize, &vdentries);
3435
3436       Output_section_data* vddata =
3437         new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
3438
3439       vdsec->add_output_section_data(vddata);
3440       vdsec->set_link_section(dynstr);
3441       vdsec->set_info(vdentries);
3442
3443       odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
3444       odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
3445     }
3446
3447   if (versions->any_needs())
3448     {
3449       Output_section* vnsec;
3450       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
3451                                           elfcpp::SHT_GNU_verneed,
3452                                           elfcpp::SHF_ALLOC,
3453                                           false, ORDER_DYNAMIC_LINKER, false);
3454
3455       unsigned char* vnbuf;
3456       unsigned int vnsize;
3457       unsigned int vnentries;
3458       versions->need_section_contents<size, big_endian>(&this->dynpool_,
3459                                                         &vnbuf, &vnsize,
3460                                                         &vnentries);
3461
3462       Output_section_data* vndata =
3463         new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
3464
3465       vnsec->add_output_section_data(vndata);
3466       vnsec->set_link_section(dynstr);
3467       vnsec->set_info(vnentries);
3468
3469       odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
3470       odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
3471     }
3472 }
3473
3474 // Create the .interp section and PT_INTERP segment.
3475
3476 void
3477 Layout::create_interp(const Target* target)
3478 {
3479   const char* interp = parameters->options().dynamic_linker();
3480   if (interp == NULL)
3481     {
3482       interp = target->dynamic_linker();
3483       gold_assert(interp != NULL);
3484     }
3485
3486   size_t len = strlen(interp) + 1;
3487
3488   Output_section_data* odata = new Output_data_const(interp, len, 1);
3489
3490   Output_section* osec = this->choose_output_section(NULL, ".interp",
3491                                                      elfcpp::SHT_PROGBITS,
3492                                                      elfcpp::SHF_ALLOC,
3493                                                      false, ORDER_INTERP,
3494                                                      false);
3495   osec->add_output_section_data(odata);
3496
3497   if (!this->script_options_->saw_phdrs_clause())
3498     {
3499       Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
3500                                                        elfcpp::PF_R);
3501       oseg->add_output_section_to_nonload(osec, elfcpp::PF_R);
3502     }
3503 }
3504
3505 // Add dynamic tags for the PLT and the dynamic relocs.  This is
3506 // called by the target-specific code.  This does nothing if not doing
3507 // a dynamic link.
3508
3509 // USE_REL is true for REL relocs rather than RELA relocs.
3510
3511 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3512
3513 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3514 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
3515 // some targets have multiple reloc sections in PLT_REL.
3516
3517 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3518 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3519
3520 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3521 // executable.
3522
3523 void
3524 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
3525                                 const Output_data* plt_rel,
3526                                 const Output_data_reloc_generic* dyn_rel,
3527                                 bool add_debug, bool dynrel_includes_plt)
3528 {
3529   Output_data_dynamic* odyn = this->dynamic_data_;
3530   if (odyn == NULL)
3531     return;
3532
3533   if (plt_got != NULL && plt_got->output_section() != NULL)
3534     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
3535
3536   if (plt_rel != NULL && plt_rel->output_section() != NULL)
3537     {
3538       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
3539       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
3540       odyn->add_constant(elfcpp::DT_PLTREL,
3541                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
3542     }
3543
3544   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
3545     {
3546       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
3547                                 dyn_rel);
3548       if (plt_rel != NULL && dynrel_includes_plt)
3549         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3550                                dyn_rel, plt_rel);
3551       else
3552         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3553                                dyn_rel);
3554       const int size = parameters->target().get_size();
3555       elfcpp::DT rel_tag;
3556       int rel_size;
3557       if (use_rel)
3558         {
3559           rel_tag = elfcpp::DT_RELENT;
3560           if (size == 32)
3561             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
3562           else if (size == 64)
3563             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
3564           else
3565             gold_unreachable();
3566         }
3567       else
3568         {
3569           rel_tag = elfcpp::DT_RELAENT;
3570           if (size == 32)
3571             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
3572           else if (size == 64)
3573             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
3574           else
3575             gold_unreachable();
3576         }
3577       odyn->add_constant(rel_tag, rel_size);
3578
3579       if (parameters->options().combreloc())
3580         {
3581           size_t c = dyn_rel->relative_reloc_count();
3582           if (c > 0)
3583             odyn->add_constant((use_rel
3584                                 ? elfcpp::DT_RELCOUNT
3585                                 : elfcpp::DT_RELACOUNT),
3586                                c);
3587         }
3588     }
3589
3590   if (add_debug && !parameters->options().shared())
3591     {
3592       // The value of the DT_DEBUG tag is filled in by the dynamic
3593       // linker at run time, and used by the debugger.
3594       odyn->add_constant(elfcpp::DT_DEBUG, 0);
3595     }
3596 }
3597
3598 // Finish the .dynamic section and PT_DYNAMIC segment.
3599
3600 void
3601 Layout::finish_dynamic_section(const Input_objects* input_objects,
3602                                const Symbol_table* symtab)
3603 {
3604   if (!this->script_options_->saw_phdrs_clause())
3605     {
3606       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
3607                                                        (elfcpp::PF_R
3608                                                         | elfcpp::PF_W));
3609       oseg->add_output_section_to_nonload(this->dynamic_section_,
3610                                           elfcpp::PF_R | elfcpp::PF_W);
3611     }
3612
3613   Output_data_dynamic* const odyn = this->dynamic_data_;
3614
3615   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
3616        p != input_objects->dynobj_end();
3617        ++p)
3618     {
3619       if (!(*p)->is_needed()
3620           && (*p)->input_file()->options().as_needed())
3621         {
3622           // This dynamic object was linked with --as-needed, but it
3623           // is not needed.
3624           continue;
3625         }
3626
3627       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
3628     }
3629
3630   if (parameters->options().shared())
3631     {
3632       const char* soname = parameters->options().soname();
3633       if (soname != NULL)
3634         odyn->add_string(elfcpp::DT_SONAME, soname);
3635     }
3636
3637   Symbol* sym = symtab->lookup(parameters->options().init());
3638   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3639     odyn->add_symbol(elfcpp::DT_INIT, sym);
3640
3641   sym = symtab->lookup(parameters->options().fini());
3642   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3643     odyn->add_symbol(elfcpp::DT_FINI, sym);
3644
3645   // Look for .init_array, .preinit_array and .fini_array by checking
3646   // section types.
3647   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
3648       p != this->section_list_.end();
3649       ++p)
3650     switch((*p)->type())
3651       {
3652       case elfcpp::SHT_FINI_ARRAY:
3653         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
3654         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
3655         break;
3656       case elfcpp::SHT_INIT_ARRAY:
3657         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
3658         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
3659         break;
3660       case elfcpp::SHT_PREINIT_ARRAY:
3661         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
3662         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
3663         break;
3664       default:
3665         break;
3666       }
3667
3668   // Add a DT_RPATH entry if needed.
3669   const General_options::Dir_list& rpath(parameters->options().rpath());
3670   if (!rpath.empty())
3671     {
3672       std::string rpath_val;
3673       for (General_options::Dir_list::const_iterator p = rpath.begin();
3674            p != rpath.end();
3675            ++p)
3676         {
3677           if (rpath_val.empty())
3678             rpath_val = p->name();
3679           else
3680             {
3681               // Eliminate duplicates.
3682               General_options::Dir_list::const_iterator q;
3683               for (q = rpath.begin(); q != p; ++q)
3684                 if (q->name() == p->name())
3685                   break;
3686               if (q == p)
3687                 {
3688                   rpath_val += ':';
3689                   rpath_val += p->name();
3690                 }
3691             }
3692         }
3693
3694       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
3695       if (parameters->options().enable_new_dtags())
3696         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
3697     }
3698
3699   // Look for text segments that have dynamic relocations.
3700   bool have_textrel = false;
3701   if (!this->script_options_->saw_sections_clause())
3702     {
3703       for (Segment_list::const_iterator p = this->segment_list_.begin();
3704            p != this->segment_list_.end();
3705            ++p)
3706         {
3707           if (((*p)->flags() & elfcpp::PF_W) == 0
3708               && (*p)->has_dynamic_reloc())
3709             {
3710               have_textrel = true;
3711               break;
3712             }
3713         }
3714     }
3715   else
3716     {
3717       // We don't know the section -> segment mapping, so we are
3718       // conservative and just look for readonly sections with
3719       // relocations.  If those sections wind up in writable segments,
3720       // then we have created an unnecessary DT_TEXTREL entry.
3721       for (Section_list::const_iterator p = this->section_list_.begin();
3722            p != this->section_list_.end();
3723            ++p)
3724         {
3725           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
3726               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
3727               && ((*p)->has_dynamic_reloc()))
3728             {
3729               have_textrel = true;
3730               break;
3731             }
3732         }
3733     }
3734
3735   // Add a DT_FLAGS entry. We add it even if no flags are set so that
3736   // post-link tools can easily modify these flags if desired.
3737   unsigned int flags = 0;
3738   if (have_textrel)
3739     {
3740       // Add a DT_TEXTREL for compatibility with older loaders.
3741       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
3742       flags |= elfcpp::DF_TEXTREL;
3743
3744       if (parameters->options().text())
3745         gold_error(_("read-only segment has dynamic relocations"));
3746       else if (parameters->options().warn_shared_textrel()
3747                && parameters->options().shared())
3748         gold_warning(_("shared library text segment is not shareable"));
3749     }
3750   if (parameters->options().shared() && this->has_static_tls())
3751     flags |= elfcpp::DF_STATIC_TLS;
3752   if (parameters->options().origin())
3753     flags |= elfcpp::DF_ORIGIN;
3754   if (parameters->options().Bsymbolic())
3755     {
3756       flags |= elfcpp::DF_SYMBOLIC;
3757       // Add DT_SYMBOLIC for compatibility with older loaders.
3758       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
3759     }
3760   if (parameters->options().now())
3761     flags |= elfcpp::DF_BIND_NOW;
3762   odyn->add_constant(elfcpp::DT_FLAGS, flags);
3763
3764   flags = 0;
3765   if (parameters->options().initfirst())
3766     flags |= elfcpp::DF_1_INITFIRST;
3767   if (parameters->options().interpose())
3768     flags |= elfcpp::DF_1_INTERPOSE;
3769   if (parameters->options().loadfltr())
3770     flags |= elfcpp::DF_1_LOADFLTR;
3771   if (parameters->options().nodefaultlib())
3772     flags |= elfcpp::DF_1_NODEFLIB;
3773   if (parameters->options().nodelete())
3774     flags |= elfcpp::DF_1_NODELETE;
3775   if (parameters->options().nodlopen())
3776     flags |= elfcpp::DF_1_NOOPEN;
3777   if (parameters->options().nodump())
3778     flags |= elfcpp::DF_1_NODUMP;
3779   if (!parameters->options().shared())
3780     flags &= ~(elfcpp::DF_1_INITFIRST
3781                | elfcpp::DF_1_NODELETE
3782                | elfcpp::DF_1_NOOPEN);
3783   if (parameters->options().origin())
3784     flags |= elfcpp::DF_1_ORIGIN;
3785   if (parameters->options().now())
3786     flags |= elfcpp::DF_1_NOW;
3787   if (flags)
3788     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
3789 }
3790
3791 // Set the size of the _DYNAMIC symbol table to be the size of the
3792 // dynamic data.
3793
3794 void
3795 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
3796 {
3797   Output_data_dynamic* const odyn = this->dynamic_data_;
3798   odyn->finalize_data_size();
3799   off_t data_size = odyn->data_size();
3800   const int size = parameters->target().get_size();
3801   if (size == 32)
3802     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
3803   else if (size == 64)
3804     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
3805   else
3806     gold_unreachable();
3807 }
3808
3809 // The mapping of input section name prefixes to output section names.
3810 // In some cases one prefix is itself a prefix of another prefix; in
3811 // such a case the longer prefix must come first.  These prefixes are
3812 // based on the GNU linker default ELF linker script.
3813
3814 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
3815 const Layout::Section_name_mapping Layout::section_name_mapping[] =
3816 {
3817   MAPPING_INIT(".text.", ".text"),
3818   MAPPING_INIT(".ctors.", ".ctors"),
3819   MAPPING_INIT(".dtors.", ".dtors"),
3820   MAPPING_INIT(".rodata.", ".rodata"),
3821   MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
3822   MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
3823   MAPPING_INIT(".data.", ".data"),
3824   MAPPING_INIT(".bss.", ".bss"),
3825   MAPPING_INIT(".tdata.", ".tdata"),
3826   MAPPING_INIT(".tbss.", ".tbss"),
3827   MAPPING_INIT(".init_array.", ".init_array"),
3828   MAPPING_INIT(".fini_array.", ".fini_array"),
3829   MAPPING_INIT(".sdata.", ".sdata"),
3830   MAPPING_INIT(".sbss.", ".sbss"),
3831   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
3832   // differently depending on whether it is creating a shared library.
3833   MAPPING_INIT(".sdata2.", ".sdata"),
3834   MAPPING_INIT(".sbss2.", ".sbss"),
3835   MAPPING_INIT(".lrodata.", ".lrodata"),
3836   MAPPING_INIT(".ldata.", ".ldata"),
3837   MAPPING_INIT(".lbss.", ".lbss"),
3838   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
3839   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
3840   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
3841   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
3842   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
3843   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
3844   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
3845   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
3846   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
3847   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
3848   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
3849   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
3850   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
3851   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
3852   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
3853   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
3854   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
3855   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
3856   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
3857   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
3858   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
3859 };
3860 #undef MAPPING_INIT
3861
3862 const int Layout::section_name_mapping_count =
3863   (sizeof(Layout::section_name_mapping)
3864    / sizeof(Layout::section_name_mapping[0]));
3865
3866 // Choose the output section name to use given an input section name.
3867 // Set *PLEN to the length of the name.  *PLEN is initialized to the
3868 // length of NAME.
3869
3870 const char*
3871 Layout::output_section_name(const char* name, size_t* plen)
3872 {
3873   // gcc 4.3 generates the following sorts of section names when it
3874   // needs a section name specific to a function:
3875   //   .text.FN
3876   //   .rodata.FN
3877   //   .sdata2.FN
3878   //   .data.FN
3879   //   .data.rel.FN
3880   //   .data.rel.local.FN
3881   //   .data.rel.ro.FN
3882   //   .data.rel.ro.local.FN
3883   //   .sdata.FN
3884   //   .bss.FN
3885   //   .sbss.FN
3886   //   .tdata.FN
3887   //   .tbss.FN
3888
3889   // The GNU linker maps all of those to the part before the .FN,
3890   // except that .data.rel.local.FN is mapped to .data, and
3891   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
3892   // beginning with .data.rel.ro.local are grouped together.
3893
3894   // For an anonymous namespace, the string FN can contain a '.'.
3895
3896   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
3897   // GNU linker maps to .rodata.
3898
3899   // The .data.rel.ro sections are used with -z relro.  The sections
3900   // are recognized by name.  We use the same names that the GNU
3901   // linker does for these sections.
3902
3903   // It is hard to handle this in a principled way, so we don't even
3904   // try.  We use a table of mappings.  If the input section name is
3905   // not found in the table, we simply use it as the output section
3906   // name.
3907
3908   const Section_name_mapping* psnm = section_name_mapping;
3909   for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
3910     {
3911       if (strncmp(name, psnm->from, psnm->fromlen) == 0)
3912         {
3913           *plen = psnm->tolen;
3914           return psnm->to;
3915         }
3916     }
3917
3918   // Compressed debug sections should be mapped to the corresponding
3919   // uncompressed section.
3920   if (is_compressed_debug_section(name))
3921     {
3922       size_t len = strlen(name);
3923       char* uncompressed_name = new char[len];
3924       uncompressed_name[0] = '.';
3925       gold_assert(name[0] == '.' && name[1] == 'z');
3926       strncpy(&uncompressed_name[1], &name[2], len - 2);
3927       uncompressed_name[len - 1] = '\0';
3928       *plen = len - 1;
3929       return uncompressed_name;
3930     }
3931
3932   return name;
3933 }
3934
3935 // Check if a comdat group or .gnu.linkonce section with the given
3936 // NAME is selected for the link.  If there is already a section,
3937 // *KEPT_SECTION is set to point to the existing section and the
3938 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
3939 // IS_GROUP_NAME are recorded for this NAME in the layout object,
3940 // *KEPT_SECTION is set to the internal copy and the function returns
3941 // true.
3942
3943 bool
3944 Layout::find_or_add_kept_section(const std::string& name,
3945                                  Relobj* object,
3946                                  unsigned int shndx,
3947                                  bool is_comdat,
3948                                  bool is_group_name,
3949                                  Kept_section** kept_section)
3950 {
3951   // It's normal to see a couple of entries here, for the x86 thunk
3952   // sections.  If we see more than a few, we're linking a C++
3953   // program, and we resize to get more space to minimize rehashing.
3954   if (this->signatures_.size() > 4
3955       && !this->resized_signatures_)
3956     {
3957       reserve_unordered_map(&this->signatures_,
3958                             this->number_of_input_files_ * 64);
3959       this->resized_signatures_ = true;
3960     }
3961
3962   Kept_section candidate;
3963   std::pair<Signatures::iterator, bool> ins =
3964     this->signatures_.insert(std::make_pair(name, candidate));
3965
3966   if (kept_section != NULL)
3967     *kept_section = &ins.first->second;
3968   if (ins.second)
3969     {
3970       // This is the first time we've seen this signature.
3971       ins.first->second.set_object(object);
3972       ins.first->second.set_shndx(shndx);
3973       if (is_comdat)
3974         ins.first->second.set_is_comdat();
3975       if (is_group_name)
3976         ins.first->second.set_is_group_name();
3977       return true;
3978     }
3979
3980   // We have already seen this signature.
3981
3982   if (ins.first->second.is_group_name())
3983     {
3984       // We've already seen a real section group with this signature.
3985       // If the kept group is from a plugin object, and we're in the
3986       // replacement phase, accept the new one as a replacement.
3987       if (ins.first->second.object() == NULL
3988           && parameters->options().plugins()->in_replacement_phase())
3989         {
3990           ins.first->second.set_object(object);
3991           ins.first->second.set_shndx(shndx);
3992           return true;
3993         }
3994       return false;
3995     }
3996   else if (is_group_name)
3997     {
3998       // This is a real section group, and we've already seen a
3999       // linkonce section with this signature.  Record that we've seen
4000       // a section group, and don't include this section group.
4001       ins.first->second.set_is_group_name();
4002       return false;
4003     }
4004   else
4005     {
4006       // We've already seen a linkonce section and this is a linkonce
4007       // section.  These don't block each other--this may be the same
4008       // symbol name with different section types.
4009       return true;
4010     }
4011 }
4012
4013 // Store the allocated sections into the section list.
4014
4015 void
4016 Layout::get_allocated_sections(Section_list* section_list) const
4017 {
4018   for (Section_list::const_iterator p = this->section_list_.begin();
4019        p != this->section_list_.end();
4020        ++p)
4021     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4022       section_list->push_back(*p);
4023 }
4024
4025 // Create an output segment.
4026
4027 Output_segment*
4028 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4029 {
4030   gold_assert(!parameters->options().relocatable());
4031   Output_segment* oseg = new Output_segment(type, flags);
4032   this->segment_list_.push_back(oseg);
4033
4034   if (type == elfcpp::PT_TLS)
4035     this->tls_segment_ = oseg;
4036   else if (type == elfcpp::PT_GNU_RELRO)
4037     this->relro_segment_ = oseg;
4038
4039   return oseg;
4040 }
4041
4042 // Write out the Output_sections.  Most won't have anything to write,
4043 // since most of the data will come from input sections which are
4044 // handled elsewhere.  But some Output_sections do have Output_data.
4045
4046 void
4047 Layout::write_output_sections(Output_file* of) const
4048 {
4049   for (Section_list::const_iterator p = this->section_list_.begin();
4050        p != this->section_list_.end();
4051        ++p)
4052     {
4053       if (!(*p)->after_input_sections())
4054         (*p)->write(of);
4055     }
4056 }
4057
4058 // Write out data not associated with a section or the symbol table.
4059
4060 void
4061 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4062 {
4063   if (!parameters->options().strip_all())
4064     {
4065       const Output_section* symtab_section = this->symtab_section_;
4066       for (Section_list::const_iterator p = this->section_list_.begin();
4067            p != this->section_list_.end();
4068            ++p)
4069         {
4070           if ((*p)->needs_symtab_index())
4071             {
4072               gold_assert(symtab_section != NULL);
4073               unsigned int index = (*p)->symtab_index();
4074               gold_assert(index > 0 && index != -1U);
4075               off_t off = (symtab_section->offset()
4076                            + index * symtab_section->entsize());
4077               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4078             }
4079         }
4080     }
4081
4082   const Output_section* dynsym_section = this->dynsym_section_;
4083   for (Section_list::const_iterator p = this->section_list_.begin();
4084        p != this->section_list_.end();
4085        ++p)
4086     {
4087       if ((*p)->needs_dynsym_index())
4088         {
4089           gold_assert(dynsym_section != NULL);
4090           unsigned int index = (*p)->dynsym_index();
4091           gold_assert(index > 0 && index != -1U);
4092           off_t off = (dynsym_section->offset()
4093                        + index * dynsym_section->entsize());
4094           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4095         }
4096     }
4097
4098   // Write out the Output_data which are not in an Output_section.
4099   for (Data_list::const_iterator p = this->special_output_list_.begin();
4100        p != this->special_output_list_.end();
4101        ++p)
4102     (*p)->write(of);
4103 }
4104
4105 // Write out the Output_sections which can only be written after the
4106 // input sections are complete.
4107
4108 void
4109 Layout::write_sections_after_input_sections(Output_file* of)
4110 {
4111   // Determine the final section offsets, and thus the final output
4112   // file size.  Note we finalize the .shstrab last, to allow the
4113   // after_input_section sections to modify their section-names before
4114   // writing.
4115   if (this->any_postprocessing_sections_)
4116     {
4117       off_t off = this->output_file_size_;
4118       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4119
4120       // Now that we've finalized the names, we can finalize the shstrab.
4121       off =
4122         this->set_section_offsets(off,
4123                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4124
4125       if (off > this->output_file_size_)
4126         {
4127           of->resize(off);
4128           this->output_file_size_ = off;
4129         }
4130     }
4131
4132   for (Section_list::const_iterator p = this->section_list_.begin();
4133        p != this->section_list_.end();
4134        ++p)
4135     {
4136       if ((*p)->after_input_sections())
4137         (*p)->write(of);
4138     }
4139
4140   this->section_headers_->write(of);
4141 }
4142
4143 // If the build ID requires computing a checksum, do so here, and
4144 // write it out.  We compute a checksum over the entire file because
4145 // that is simplest.
4146
4147 void
4148 Layout::write_build_id(Output_file* of) const
4149 {
4150   if (this->build_id_note_ == NULL)
4151     return;
4152
4153   const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4154
4155   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4156                                           this->build_id_note_->data_size());
4157
4158   const char* style = parameters->options().build_id();
4159   if (strcmp(style, "sha1") == 0)
4160     {
4161       sha1_ctx ctx;
4162       sha1_init_ctx(&ctx);
4163       sha1_process_bytes(iv, this->output_file_size_, &ctx);
4164       sha1_finish_ctx(&ctx, ov);
4165     }
4166   else if (strcmp(style, "md5") == 0)
4167     {
4168       md5_ctx ctx;
4169       md5_init_ctx(&ctx);
4170       md5_process_bytes(iv, this->output_file_size_, &ctx);
4171       md5_finish_ctx(&ctx, ov);
4172     }
4173   else
4174     gold_unreachable();
4175
4176   of->write_output_view(this->build_id_note_->offset(),
4177                         this->build_id_note_->data_size(),
4178                         ov);
4179
4180   of->free_input_view(0, this->output_file_size_, iv);
4181 }
4182
4183 // Write out a binary file.  This is called after the link is
4184 // complete.  IN is the temporary output file we used to generate the
4185 // ELF code.  We simply walk through the segments, read them from
4186 // their file offset in IN, and write them to their load address in
4187 // the output file.  FIXME: with a bit more work, we could support
4188 // S-records and/or Intel hex format here.
4189
4190 void
4191 Layout::write_binary(Output_file* in) const
4192 {
4193   gold_assert(parameters->options().oformat_enum()
4194               == General_options::OBJECT_FORMAT_BINARY);
4195
4196   // Get the size of the binary file.
4197   uint64_t max_load_address = 0;
4198   for (Segment_list::const_iterator p = this->segment_list_.begin();
4199        p != this->segment_list_.end();
4200        ++p)
4201     {
4202       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4203         {
4204           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4205           if (max_paddr > max_load_address)
4206             max_load_address = max_paddr;
4207         }
4208     }
4209
4210   Output_file out(parameters->options().output_file_name());
4211   out.open(max_load_address);
4212
4213   for (Segment_list::const_iterator p = this->segment_list_.begin();
4214        p != this->segment_list_.end();
4215        ++p)
4216     {
4217       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4218         {
4219           const unsigned char* vin = in->get_input_view((*p)->offset(),
4220                                                         (*p)->filesz());
4221           unsigned char* vout = out.get_output_view((*p)->paddr(),
4222                                                     (*p)->filesz());
4223           memcpy(vout, vin, (*p)->filesz());
4224           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4225           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4226         }
4227     }
4228
4229   out.close();
4230 }
4231
4232 // Print the output sections to the map file.
4233
4234 void
4235 Layout::print_to_mapfile(Mapfile* mapfile) const
4236 {
4237   for (Segment_list::const_iterator p = this->segment_list_.begin();
4238        p != this->segment_list_.end();
4239        ++p)
4240     (*p)->print_sections_to_mapfile(mapfile);
4241 }
4242
4243 // Print statistical information to stderr.  This is used for --stats.
4244
4245 void
4246 Layout::print_stats() const
4247 {
4248   this->namepool_.print_stats("section name pool");
4249   this->sympool_.print_stats("output symbol name pool");
4250   this->dynpool_.print_stats("dynamic name pool");
4251
4252   for (Section_list::const_iterator p = this->section_list_.begin();
4253        p != this->section_list_.end();
4254        ++p)
4255     (*p)->print_merge_stats();
4256 }
4257
4258 // Write_sections_task methods.
4259
4260 // We can always run this task.
4261
4262 Task_token*
4263 Write_sections_task::is_runnable()
4264 {
4265   return NULL;
4266 }
4267
4268 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4269 // when finished.
4270
4271 void
4272 Write_sections_task::locks(Task_locker* tl)
4273 {
4274   tl->add(this, this->output_sections_blocker_);
4275   tl->add(this, this->final_blocker_);
4276 }
4277
4278 // Run the task--write out the data.
4279
4280 void
4281 Write_sections_task::run(Workqueue*)
4282 {
4283   this->layout_->write_output_sections(this->of_);
4284 }
4285
4286 // Write_data_task methods.
4287
4288 // We can always run this task.
4289
4290 Task_token*
4291 Write_data_task::is_runnable()
4292 {
4293   return NULL;
4294 }
4295
4296 // We need to unlock FINAL_BLOCKER when finished.
4297
4298 void
4299 Write_data_task::locks(Task_locker* tl)
4300 {
4301   tl->add(this, this->final_blocker_);
4302 }
4303
4304 // Run the task--write out the data.
4305
4306 void
4307 Write_data_task::run(Workqueue*)
4308 {
4309   this->layout_->write_data(this->symtab_, this->of_);
4310 }
4311
4312 // Write_symbols_task methods.
4313
4314 // We can always run this task.
4315
4316 Task_token*
4317 Write_symbols_task::is_runnable()
4318 {
4319   return NULL;
4320 }
4321
4322 // We need to unlock FINAL_BLOCKER when finished.
4323
4324 void
4325 Write_symbols_task::locks(Task_locker* tl)
4326 {
4327   tl->add(this, this->final_blocker_);
4328 }
4329
4330 // Run the task--write out the symbols.
4331
4332 void
4333 Write_symbols_task::run(Workqueue*)
4334 {
4335   this->symtab_->write_globals(this->sympool_, this->dynpool_,
4336                                this->layout_->symtab_xindex(),
4337                                this->layout_->dynsym_xindex(), this->of_);
4338 }
4339
4340 // Write_after_input_sections_task methods.
4341
4342 // We can only run this task after the input sections have completed.
4343
4344 Task_token*
4345 Write_after_input_sections_task::is_runnable()
4346 {
4347   if (this->input_sections_blocker_->is_blocked())
4348     return this->input_sections_blocker_;
4349   return NULL;
4350 }
4351
4352 // We need to unlock FINAL_BLOCKER when finished.
4353
4354 void
4355 Write_after_input_sections_task::locks(Task_locker* tl)
4356 {
4357   tl->add(this, this->final_blocker_);
4358 }
4359
4360 // Run the task.
4361
4362 void
4363 Write_after_input_sections_task::run(Workqueue*)
4364 {
4365   this->layout_->write_sections_after_input_sections(this->of_);
4366 }
4367
4368 // Close_task_runner methods.
4369
4370 // Run the task--close the file.
4371
4372 void
4373 Close_task_runner::run(Workqueue*, const Task*)
4374 {
4375   // If we need to compute a checksum for the BUILD if, we do so here.
4376   this->layout_->write_build_id(this->of_);
4377
4378   // If we've been asked to create a binary file, we do so here.
4379   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
4380     this->layout_->write_binary(this->of_);
4381
4382   this->of_->close();
4383 }
4384
4385 // Instantiate the templates we need.  We could use the configure
4386 // script to restrict this to only the ones for implemented targets.
4387
4388 #ifdef HAVE_TARGET_32_LITTLE
4389 template
4390 Output_section*
4391 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
4392                           const char* name,
4393                           const elfcpp::Shdr<32, false>& shdr,
4394                           unsigned int, unsigned int, off_t*);
4395 #endif
4396
4397 #ifdef HAVE_TARGET_32_BIG
4398 template
4399 Output_section*
4400 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
4401                          const char* name,
4402                          const elfcpp::Shdr<32, true>& shdr,
4403                          unsigned int, unsigned int, off_t*);
4404 #endif
4405
4406 #ifdef HAVE_TARGET_64_LITTLE
4407 template
4408 Output_section*
4409 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
4410                           const char* name,
4411                           const elfcpp::Shdr<64, false>& shdr,
4412                           unsigned int, unsigned int, off_t*);
4413 #endif
4414
4415 #ifdef HAVE_TARGET_64_BIG
4416 template
4417 Output_section*
4418 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
4419                          const char* name,
4420                          const elfcpp::Shdr<64, true>& shdr,
4421                          unsigned int, unsigned int, off_t*);
4422 #endif
4423
4424 #ifdef HAVE_TARGET_32_LITTLE
4425 template
4426 Output_section*
4427 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
4428                                 unsigned int reloc_shndx,
4429                                 const elfcpp::Shdr<32, false>& shdr,
4430                                 Output_section* data_section,
4431                                 Relocatable_relocs* rr);
4432 #endif
4433
4434 #ifdef HAVE_TARGET_32_BIG
4435 template
4436 Output_section*
4437 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
4438                                unsigned int reloc_shndx,
4439                                const elfcpp::Shdr<32, true>& shdr,
4440                                Output_section* data_section,
4441                                Relocatable_relocs* rr);
4442 #endif
4443
4444 #ifdef HAVE_TARGET_64_LITTLE
4445 template
4446 Output_section*
4447 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
4448                                 unsigned int reloc_shndx,
4449                                 const elfcpp::Shdr<64, false>& shdr,
4450                                 Output_section* data_section,
4451                                 Relocatable_relocs* rr);
4452 #endif
4453
4454 #ifdef HAVE_TARGET_64_BIG
4455 template
4456 Output_section*
4457 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
4458                                unsigned int reloc_shndx,
4459                                const elfcpp::Shdr<64, true>& shdr,
4460                                Output_section* data_section,
4461                                Relocatable_relocs* rr);
4462 #endif
4463
4464 #ifdef HAVE_TARGET_32_LITTLE
4465 template
4466 void
4467 Layout::layout_group<32, false>(Symbol_table* symtab,
4468                                 Sized_relobj<32, false>* object,
4469                                 unsigned int,
4470                                 const char* group_section_name,
4471                                 const char* signature,
4472                                 const elfcpp::Shdr<32, false>& shdr,
4473                                 elfcpp::Elf_Word flags,
4474                                 std::vector<unsigned int>* shndxes);
4475 #endif
4476
4477 #ifdef HAVE_TARGET_32_BIG
4478 template
4479 void
4480 Layout::layout_group<32, true>(Symbol_table* symtab,
4481                                Sized_relobj<32, true>* object,
4482                                unsigned int,
4483                                const char* group_section_name,
4484                                const char* signature,
4485                                const elfcpp::Shdr<32, true>& shdr,
4486                                elfcpp::Elf_Word flags,
4487                                std::vector<unsigned int>* shndxes);
4488 #endif
4489
4490 #ifdef HAVE_TARGET_64_LITTLE
4491 template
4492 void
4493 Layout::layout_group<64, false>(Symbol_table* symtab,
4494                                 Sized_relobj<64, false>* object,
4495                                 unsigned int,
4496                                 const char* group_section_name,
4497                                 const char* signature,
4498                                 const elfcpp::Shdr<64, false>& shdr,
4499                                 elfcpp::Elf_Word flags,
4500                                 std::vector<unsigned int>* shndxes);
4501 #endif
4502
4503 #ifdef HAVE_TARGET_64_BIG
4504 template
4505 void
4506 Layout::layout_group<64, true>(Symbol_table* symtab,
4507                                Sized_relobj<64, true>* object,
4508                                unsigned int,
4509                                const char* group_section_name,
4510                                const char* signature,
4511                                const elfcpp::Shdr<64, true>& shdr,
4512                                elfcpp::Elf_Word flags,
4513                                std::vector<unsigned int>* shndxes);
4514 #endif
4515
4516 #ifdef HAVE_TARGET_32_LITTLE
4517 template
4518 Output_section*
4519 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
4520                                    const unsigned char* symbols,
4521                                    off_t symbols_size,
4522                                    const unsigned char* symbol_names,
4523                                    off_t symbol_names_size,
4524                                    unsigned int shndx,
4525                                    const elfcpp::Shdr<32, false>& shdr,
4526                                    unsigned int reloc_shndx,
4527                                    unsigned int reloc_type,
4528                                    off_t* off);
4529 #endif
4530
4531 #ifdef HAVE_TARGET_32_BIG
4532 template
4533 Output_section*
4534 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
4535                                    const unsigned char* symbols,
4536                                    off_t symbols_size,
4537                                   const unsigned char* symbol_names,
4538                                   off_t symbol_names_size,
4539                                   unsigned int shndx,
4540                                   const elfcpp::Shdr<32, true>& shdr,
4541                                   unsigned int reloc_shndx,
4542                                   unsigned int reloc_type,
4543                                   off_t* off);
4544 #endif
4545
4546 #ifdef HAVE_TARGET_64_LITTLE
4547 template
4548 Output_section*
4549 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
4550                                    const unsigned char* symbols,
4551                                    off_t symbols_size,
4552                                    const unsigned char* symbol_names,
4553                                    off_t symbol_names_size,
4554                                    unsigned int shndx,
4555                                    const elfcpp::Shdr<64, false>& shdr,
4556                                    unsigned int reloc_shndx,
4557                                    unsigned int reloc_type,
4558                                    off_t* off);
4559 #endif
4560
4561 #ifdef HAVE_TARGET_64_BIG
4562 template
4563 Output_section*
4564 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
4565                                    const unsigned char* symbols,
4566                                    off_t symbols_size,
4567                                   const unsigned char* symbol_names,
4568                                   off_t symbol_names_size,
4569                                   unsigned int shndx,
4570                                   const elfcpp::Shdr<64, true>& shdr,
4571                                   unsigned int reloc_shndx,
4572                                   unsigned int reloc_type,
4573                                   off_t* off);
4574 #endif
4575
4576 } // End namespace gold.