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_GROUP
 493               | elfcpp::SHF_MERGE
 494               | elfcpp::SHF_STRINGS);
 495
 496   // We only clear the SHF_LINK_ORDER flag in for
 497   // a non-relocatable link.
 498   if (!parameters->options().relocatable())
 499     flags &= ~elfcpp::SHF_LINK_ORDER;
 500
 501   if (this->script_options_->saw_sections_clause())
 502     {
 503       // We are using a SECTIONS clause, so the output section is
 504       // chosen based only on the name.
 505
 506       Script_sections* ss = this->script_options_->script_sections();
 507       const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
 508       Output_section** output_section_slot;
 509       Script_sections::Section_type script_section_type;
 510       const char* orig_name = name;
 511       name = ss->output_section_name(file_name, name, &output_section_slot,
 512                                      &script_section_type);
 513       if (name == NULL)
 514         {
 515           gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
 516                                      "because it is not allowed by the "
 517                                      "SECTIONS clause of the linker script"),
 518                      orig_name);
 519           // The SECTIONS clause says to discard this input section.
 520           return NULL;
 521         }
 522
 523       // We can only handle script section types ST_NONE and ST_NOLOAD.
 524       switch (script_section_type)
 525         {
 526         case Script_sections::ST_NONE:
 527           break;
 528         case Script_sections::ST_NOLOAD:
 529           flags &= elfcpp::SHF_ALLOC;
 530           break;
 531         default:
 532           gold_unreachable();
 533         }
 534
 535       // If this is an orphan section--one not mentioned in the linker
 536       // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
 537       // default processing below.
 538
 539       if (output_section_slot != NULL)
 540         {
 541           if (*output_section_slot != NULL)
 542             {
 543               (*output_section_slot)->update_flags_for_input_section(flags);
 544               return *output_section_slot;
 545             }
 546
 547           // We don't put sections found in the linker script into
 548           // SECTION_NAME_MAP_.  That keeps us from getting confused
 549           // if an orphan section is mapped to a section with the same
 550           // name as one in the linker script.
 551
 552           name = this->namepool_.add(name, false, NULL);
 553
 554           Output_section* os = this->make_output_section(name, type, flags,
 555                                                          order, is_relro);
 556
 557           os->set_found_in_sections_clause();
 558
 559           // Special handling for NOLOAD sections.
 560           if (script_section_type == Script_sections::ST_NOLOAD)
 561             {
 562               os->set_is_noload();
 563
 564               // The constructor of Output_section sets addresses of non-ALLOC
 565               // sections to 0 by default.  We don't want that for NOLOAD
 566               // sections even if they have no SHF_ALLOC flag.
 567               if ((os->flags() & elfcpp::SHF_ALLOC) == 0
 568                   && os->is_address_valid())
 569                 {
 570                   gold_assert(os->address() == 0
 571                               && !os->is_offset_valid()
 572                               && !os->is_data_size_valid());
 573                   os->reset_address_and_file_offset();
 574                 }
 575             }
 576
 577           *output_section_slot = os;
 578           return os;
 579         }
 580     }
 581
 582   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
 583
 584   // Turn NAME from the name of the input section into the name of the
 585   // output section.
 586
 587   size_t len = strlen(name);
 588   if (is_input_section
 589       && !this->script_options_->saw_sections_clause()
 590       && !parameters->options().relocatable())
 591     name = Layout::output_section_name(name, &len);
 592
 593   Stringpool::Key name_key;
 594   name = this->namepool_.add_with_length(name, len, true, &name_key);
 595
 596   // Find or make the output section.  The output section is selected
 597   // based on the section name, type, and flags.
 598   return this->get_output_section(name, name_key, type, flags, order, is_relro);
 599 }
 600
 601 // Return the output section to use for input section SHNDX, with name
 602 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
 603 // index of a relocation section which applies to this section, or 0
 604 // if none, or -1U if more than one.  RELOC_TYPE is the type of the
 605 // relocation section if there is one.  Set *OFF to the offset of this
 606 // input section without the output section.  Return NULL if the
 607 // section should be discarded.  Set *OFF to -1 if the section
 608 // contents should not be written directly to the output file, but
 609 // will instead receive special handling.
 610
 611 template<int size, bool big_endian>
 612 Output_section*
 613 Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
 614                const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 615                unsigned int reloc_shndx, unsigned int, off_t* off)
 616 {
 617   *off = 0;
 618
 619   if (!this->include_section(object, name, shdr))
 620     return NULL;
 621
 622   Output_section* os;
 623
 624   // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
 625   // correct section types.  Force them here.
 626   elfcpp::Elf_Word sh_type = shdr.get_sh_type();
 627   if (sh_type == elfcpp::SHT_PROGBITS)
 628     {
 629       static const char init_array_prefix[] = ".init_array";
 630       static const char preinit_array_prefix[] = ".preinit_array";
 631       static const char fini_array_prefix[] = ".fini_array";
 632       static size_t init_array_prefix_size = sizeof(init_array_prefix) - 1;
 633       static size_t preinit_array_prefix_size =
 634         sizeof(preinit_array_prefix) - 1;
 635       static size_t fini_array_prefix_size = sizeof(fini_array_prefix) - 1;
 636
 637       if (strncmp(name, init_array_prefix, init_array_prefix_size) == 0)
 638         sh_type = elfcpp::SHT_INIT_ARRAY;
 639       else if (strncmp(name, preinit_array_prefix, preinit_array_prefix_size)
 640                == 0)
 641         sh_type = elfcpp::SHT_PREINIT_ARRAY;
 642       else if (strncmp(name, fini_array_prefix, fini_array_prefix_size) == 0)
 643         sh_type = elfcpp::SHT_FINI_ARRAY;
 644     }
 645
 646   // In a relocatable link a grouped section must not be combined with
 647   // any other sections.
 648   if (parameters->options().relocatable()
 649       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
 650     {
 651       name = this->namepool_.add(name, true, NULL);
 652       os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
 653                                      ORDER_INVALID, false);
 654     }
 655   else
 656     {
 657       os = this->choose_output_section(object, name, sh_type,
 658                                        shdr.get_sh_flags(), true,
 659                                        ORDER_INVALID, false);
 660       if (os == NULL)
 661         return NULL;
 662     }
 663
 664   // By default the GNU linker sorts input sections whose names match
 665   // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*.  The sections
 666   // are sorted by name.  This is used to implement constructor
 667   // priority ordering.  We are compatible.
 668   if (!this->script_options_->saw_sections_clause()
 669       && (is_prefix_of(".ctors.", name)
 670           || is_prefix_of(".dtors.", name)
 671           || is_prefix_of(".init_array.", name)
 672           || is_prefix_of(".fini_array.", name)))
 673     os->set_must_sort_attached_input_sections();
 674
 675   // FIXME: Handle SHF_LINK_ORDER somewhere.
 676
 677   *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
 678                                this->script_options_->saw_sections_clause());
 679   this->have_added_input_section_ = true;
 680
 681   return os;
 682 }
 683
 684 // Handle a relocation section when doing a relocatable link.
 685
 686 template<int size, bool big_endian>
 687 Output_section*
 688 Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
 689                      unsigned int,
 690                      const elfcpp::Shdr<size, big_endian>& shdr,
 691                      Output_section* data_section,
 692                      Relocatable_relocs* rr)
 693 {
 694   gold_assert(parameters->options().relocatable()
 695               || parameters->options().emit_relocs());
 696
 697   int sh_type = shdr.get_sh_type();
 698
 699   std::string name;
 700   if (sh_type == elfcpp::SHT_REL)
 701     name = ".rel";
 702   else if (sh_type == elfcpp::SHT_RELA)
 703     name = ".rela";
 704   else
 705     gold_unreachable();
 706   name += data_section->name();
 707
 708   // In a relocatable link relocs for a grouped section must not be
 709   // combined with other reloc sections.
 710   Output_section* os;
 711   if (!parameters->options().relocatable()
 712       || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
 713     os = this->choose_output_section(object, name.c_str(), sh_type,
 714                                      shdr.get_sh_flags(), false,
 715                                      ORDER_INVALID, false);
 716   else
 717     {
 718       const char* n = this->namepool_.add(name.c_str(), true, NULL);
 719       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
 720                                      ORDER_INVALID, false);
 721     }
 722
 723   os->set_should_link_to_symtab();
 724   os->set_info_section(data_section);
 725
 726   Output_section_data* posd;
 727   if (sh_type == elfcpp::SHT_REL)
 728     {
 729       os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
 730       posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
 731                                            size,
 732                                            big_endian>(rr);
 733     }
 734   else if (sh_type == elfcpp::SHT_RELA)
 735     {
 736       os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
 737       posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
 738                                            size,
 739                                            big_endian>(rr);
 740     }
 741   else
 742     gold_unreachable();
 743
 744   os->add_output_section_data(posd);
 745   rr->set_output_data(posd);
 746
 747   return os;
 748 }
 749
 750 // Handle a group section when doing a relocatable link.
 751
 752 template<int size, bool big_endian>
 753 void
 754 Layout::layout_group(Symbol_table* symtab,
 755                      Sized_relobj<size, big_endian>* object,
 756                      unsigned int,
 757                      const char* group_section_name,
 758                      const char* signature,
 759                      const elfcpp::Shdr<size, big_endian>& shdr,
 760                      elfcpp::Elf_Word flags,
 761                      std::vector<unsigned int>* shndxes)
 762 {
 763   gold_assert(parameters->options().relocatable());
 764   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
 765   group_section_name = this->namepool_.add(group_section_name, true, NULL);
 766   Output_section* os = this->make_output_section(group_section_name,
 767                                                  elfcpp::SHT_GROUP,
 768                                                  shdr.get_sh_flags(),
 769                                                  ORDER_INVALID, false);
 770
 771   // We need to find a symbol with the signature in the symbol table.
 772   // If we don't find one now, we need to look again later.
 773   Symbol* sym = symtab->lookup(signature, NULL);
 774   if (sym != NULL)
 775     os->set_info_symndx(sym);
 776   else
 777     {
 778       // Reserve some space to minimize reallocations.
 779       if (this->group_signatures_.empty())
 780         this->group_signatures_.reserve(this->number_of_input_files_ * 16);
 781
 782       // We will wind up using a symbol whose name is the signature.
 783       // So just put the signature in the symbol name pool to save it.
 784       signature = symtab->canonicalize_name(signature);
 785       this->group_signatures_.push_back(Group_signature(os, signature));
 786     }
 787
 788   os->set_should_link_to_symtab();
 789   os->set_entsize(4);
 790
 791   section_size_type entry_count =
 792     convert_to_section_size_type(shdr.get_sh_size() / 4);
 793   Output_section_data* posd =
 794     new Output_data_group<size, big_endian>(object, entry_count, flags,
 795                                             shndxes);
 796   os->add_output_section_data(posd);
 797 }
 798
 799 // Special GNU handling of sections name .eh_frame.  They will
 800 // normally hold exception frame data as defined by the C++ ABI
 801 // (http://codesourcery.com/cxx-abi/).
 802
 803 template<int size, bool big_endian>
 804 Output_section*
 805 Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
 806                         const unsigned char* symbols,
 807                         off_t symbols_size,
 808                         const unsigned char* symbol_names,
 809                         off_t symbol_names_size,
 810                         unsigned int shndx,
 811                         const elfcpp::Shdr<size, big_endian>& shdr,
 812                         unsigned int reloc_shndx, unsigned int reloc_type,
 813                         off_t* off)
 814 {
 815   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
 816   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
 817
 818   const char* const name = ".eh_frame";
 819   Output_section* os = this->choose_output_section(object, name,
 820                                                    elfcpp::SHT_PROGBITS,
 821                                                    elfcpp::SHF_ALLOC, false,
 822                                                    ORDER_EHFRAME, false);
 823   if (os == NULL)
 824     return NULL;
 825
 826   if (this->eh_frame_section_ == NULL)
 827     {
 828       this->eh_frame_section_ = os;
 829       this->eh_frame_data_ = new Eh_frame();
 830
 831       if (parameters->options().eh_frame_hdr())
 832         {
 833           Output_section* hdr_os =
 834             this->choose_output_section(NULL, ".eh_frame_hdr",
 835                                         elfcpp::SHT_PROGBITS,
 836                                         elfcpp::SHF_ALLOC, false,
 837                                         ORDER_EHFRAME, false);
 838
 839           if (hdr_os != NULL)
 840             {
 841               Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
 842                                                         this->eh_frame_data_);
 843               hdr_os->add_output_section_data(hdr_posd);
 844
 845               hdr_os->set_after_input_sections();
 846
 847               if (!this->script_options_->saw_phdrs_clause())
 848                 {
 849                   Output_segment* hdr_oseg;
 850                   hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
 851                                                        elfcpp::PF_R);
 852                   hdr_oseg->add_output_section_to_nonload(hdr_os,
 853                                                           elfcpp::PF_R);
 854                 }
 855
 856               this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
 857             }
 858         }
 859     }
 860
 861   gold_assert(this->eh_frame_section_ == os);
 862
 863   if (this->eh_frame_data_->add_ehframe_input_section(object,
 864                                                       symbols,
 865                                                       symbols_size,
 866                                                       symbol_names,
 867                                                       symbol_names_size,
 868                                                       shndx,
 869                                                       reloc_shndx,
 870                                                       reloc_type))
 871     {
 872       os->update_flags_for_input_section(shdr.get_sh_flags());
 873
 874       // We found a .eh_frame section we are going to optimize, so now
 875       // we can add the set of optimized sections to the output
 876       // section.  We need to postpone adding this until we've found a
 877       // section we can optimize so that the .eh_frame section in
 878       // crtbegin.o winds up at the start of the output section.
 879       if (!this->added_eh_frame_data_)
 880         {
 881           os->add_output_section_data(this->eh_frame_data_);
 882           this->added_eh_frame_data_ = true;
 883         }
 884       *off = -1;
 885     }
 886   else
 887     {
 888       // We couldn't handle this .eh_frame section for some reason.
 889       // Add it as a normal section.
 890       bool saw_sections_clause = this->script_options_->saw_sections_clause();
 891       *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
 892                                    saw_sections_clause);
 893       this->have_added_input_section_ = true;
 894     }
 895
 896   return os;
 897 }
 898
 899 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
 900 // the output section.
 901
 902 Output_section*
 903 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
 904                                 elfcpp::Elf_Xword flags,
 905                                 Output_section_data* posd,
 906                                 Output_section_order order, bool is_relro)
 907 {
 908   Output_section* os = this->choose_output_section(NULL, name, type, flags,
 909                                                    false, order, is_relro);
 910   if (os != NULL)
 911     os->add_output_section_data(posd);
 912   return os;
 913 }
 914
 915 // Map section flags to segment flags.
 916
 917 elfcpp::Elf_Word
 918 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
 919 {
 920   elfcpp::Elf_Word ret = elfcpp::PF_R;
 921   if ((flags & elfcpp::SHF_WRITE) != 0)
 922     ret |= elfcpp::PF_W;
 923   if ((flags & elfcpp::SHF_EXECINSTR) != 0)
 924     ret |= elfcpp::PF_X;
 925   return ret;
 926 }
 927
 928 // Sometimes we compress sections.  This is typically done for
 929 // sections that are not part of normal program execution (such as
 930 // .debug_* sections), and where the readers of these sections know
 931 // how to deal with compressed sections.  This routine doesn't say for
 932 // certain whether we'll compress -- it depends on commandline options
 933 // as well -- just whether this section is a candidate for compression.
 934 // (The Output_compressed_section class decides whether to compress
 935 // a given section, and picks the name of the compressed section.)
 936
 937 static bool
 938 is_compressible_debug_section(const char* secname)
 939 {
 940   return (is_prefix_of(".debug", secname));
 941 }
 942
 943 // We may see compressed debug sections in input files.  Return TRUE
 944 // if this is the name of a compressed debug section.
 945
 946 bool
 947 is_compressed_debug_section(const char* secname)
 948 {
 949   return (is_prefix_of(".zdebug", secname));
 950 }
 951
 952 // Make a new Output_section, and attach it to segments as
 953 // appropriate.  ORDER is the order in which this section should
 954 // appear in the output segment.  IS_RELRO is true if this is a relro
 955 // (read-only after relocations) section.
 956
 957 Output_section*
 958 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
 959                             elfcpp::Elf_Xword flags,
 960                             Output_section_order order, bool is_relro)
 961 {
 962   Output_section* os;
 963   if ((flags & elfcpp::SHF_ALLOC) == 0
 964       && strcmp(parameters->options().compress_debug_sections(), "none") != 0
 965       && is_compressible_debug_section(name))
 966     os = new Output_compressed_section(&parameters->options(), name, type,
 967                                        flags);
 968   else if ((flags & elfcpp::SHF_ALLOC) == 0
 969            && parameters->options().strip_debug_non_line()
 970            && strcmp(".debug_abbrev", name) == 0)
 971     {
 972       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
 973           name, type, flags);
 974       if (this->debug_info_)
 975         this->debug_info_->set_abbreviations(this->debug_abbrev_);
 976     }
 977   else if ((flags & elfcpp::SHF_ALLOC) == 0
 978            && parameters->options().strip_debug_non_line()
 979            && strcmp(".debug_info", name) == 0)
 980     {
 981       os = this->debug_info_ = new Output_reduced_debug_info_section(
 982           name, type, flags);
 983       if (this->debug_abbrev_)
 984         this->debug_info_->set_abbreviations(this->debug_abbrev_);
 985     }
 986   else
 987     {
 988       // FIXME: const_cast is ugly.
 989       Target* target = const_cast<Target*>(&parameters->target());
 990       os = target->make_output_section(name, type, flags);
 991     }
 992
 993   // With -z relro, we have to recognize the special sections by name.
 994   // There is no other way.
 995   bool is_relro_local = false;
 996   if (!this->script_options_->saw_sections_clause()
 997       && parameters->options().relro()
 998       && type == elfcpp::SHT_PROGBITS
 999       && (flags & elfcpp::SHF_ALLOC) != 0
1000       && (flags & elfcpp::SHF_WRITE) != 0)
1001     {
1002       if (strcmp(name, ".data.rel.ro") == 0)
1003         is_relro = true;
1004       else if (strcmp(name, ".data.rel.ro.local") == 0)
1005         {
1006           is_relro = true;
1007           is_relro_local = true;
1008         }
1009       else if (type == elfcpp::SHT_INIT_ARRAY
1010                || type == elfcpp::SHT_FINI_ARRAY
1011                || type == elfcpp::SHT_PREINIT_ARRAY)
1012         is_relro = true;
1013       else if (strcmp(name, ".ctors") == 0
1014                || strcmp(name, ".dtors") == 0
1015                || strcmp(name, ".jcr") == 0)
1016         is_relro = true;
1017     }
1018
1019   if (is_relro)
1020     os->set_is_relro();
1021
1022   if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1023     order = this->default_section_order(os, is_relro_local);
1024
1025   os->set_order(order);
1026
1027   parameters->target().new_output_section(os);
1028
1029   this->section_list_.push_back(os);
1030
1031   // The GNU linker by default sorts some sections by priority, so we
1032   // do the same.  We need to know that this might happen before we
1033   // attach any input sections.
1034   if (!this->script_options_->saw_sections_clause()
1035       && (strcmp(name, ".ctors") == 0
1036           || strcmp(name, ".dtors") == 0
1037           || strcmp(name, ".init_array") == 0
1038           || strcmp(name, ".fini_array") == 0))
1039     os->set_may_sort_attached_input_sections();
1040
1041   // Check for .stab*str sections, as .stab* sections need to link to
1042   // them.
1043   if (type == elfcpp::SHT_STRTAB
1044       && !this->have_stabstr_section_
1045       && strncmp(name, ".stab", 5) == 0
1046       && strcmp(name + strlen(name) - 3, "str") == 0)
1047     this->have_stabstr_section_ = true;
1048
1049   // If we have already attached the sections to segments, then we
1050   // need to attach this one now.  This happens for sections created
1051   // directly by the linker.
1052   if (this->sections_are_attached_)
1053     this->attach_section_to_segment(os);
1054
1055   return os;
1056 }
1057
1058 // Return the default order in which a section should be placed in an
1059 // output segment.  This function captures a lot of the ideas in
1060 // ld/scripttempl/elf.sc in the GNU linker.  Note that the order of a
1061 // linker created section is normally set when the section is created;
1062 // this function is used for input sections.
1063
1064 Output_section_order
1065 Layout::default_section_order(Output_section* os, bool is_relro_local)
1066 {
1067   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1068   bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1069   bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1070   bool is_bss = false;
1071
1072   switch (os->type())
1073     {
1074     default:
1075     case elfcpp::SHT_PROGBITS:
1076       break;
1077     case elfcpp::SHT_NOBITS:
1078       is_bss = true;
1079       break;
1080     case elfcpp::SHT_RELA:
1081     case elfcpp::SHT_REL:
1082       if (!is_write)
1083         return ORDER_DYNAMIC_RELOCS;
1084       break;
1085     case elfcpp::SHT_HASH:
1086     case elfcpp::SHT_DYNAMIC:
1087     case elfcpp::SHT_SHLIB:
1088     case elfcpp::SHT_DYNSYM:
1089     case elfcpp::SHT_GNU_HASH:
1090     case elfcpp::SHT_GNU_verdef:
1091     case elfcpp::SHT_GNU_verneed:
1092     case elfcpp::SHT_GNU_versym:
1093       if (!is_write)
1094         return ORDER_DYNAMIC_LINKER;
1095       break;
1096     case elfcpp::SHT_NOTE:
1097       return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1098     }
1099
1100   if ((os->flags() & elfcpp::SHF_TLS) != 0)
1101     return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1102
1103   if (!is_bss && !is_write)
1104     {
1105       if (is_execinstr)
1106         {
1107           if (strcmp(os->name(), ".init") == 0)
1108             return ORDER_INIT;
1109           else if (strcmp(os->name(), ".fini") == 0)
1110             return ORDER_FINI;
1111         }
1112       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1113     }
1114
1115   if (os->is_relro())
1116     return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1117
1118   if (os->is_small_section())
1119     return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1120   if (os->is_large_section())
1121     return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1122
1123   return is_bss ? ORDER_BSS : ORDER_DATA;
1124 }
1125
1126 // Attach output sections to segments.  This is called after we have
1127 // seen all the input sections.
1128
1129 void
1130 Layout::attach_sections_to_segments()
1131 {
1132   for (Section_list::iterator p = this->section_list_.begin();
1133        p != this->section_list_.end();
1134        ++p)
1135     this->attach_section_to_segment(*p);
1136
1137   this->sections_are_attached_ = true;
1138 }
1139
1140 // Attach an output section to a segment.
1141
1142 void
1143 Layout::attach_section_to_segment(Output_section* os)
1144 {
1145   if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1146     this->unattached_section_list_.push_back(os);
1147   else
1148     this->attach_allocated_section_to_segment(os);
1149 }
1150
1151 // Attach an allocated output section to a segment.
1152
1153 void
1154 Layout::attach_allocated_section_to_segment(Output_section* os)
1155 {
1156   elfcpp::Elf_Xword flags = os->flags();
1157   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1158
1159   if (parameters->options().relocatable())
1160     return;
1161
1162   // If we have a SECTIONS clause, we can't handle the attachment to
1163   // segments until after we've seen all the sections.
1164   if (this->script_options_->saw_sections_clause())
1165     return;
1166
1167   gold_assert(!this->script_options_->saw_phdrs_clause());
1168
1169   // This output section goes into a PT_LOAD segment.
1170
1171   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1172
1173   // Check for --section-start.
1174   uint64_t addr;
1175   bool is_address_set = parameters->options().section_start(os->name(), &addr);
1176
1177   // In general the only thing we really care about for PT_LOAD
1178   // segments is whether or not they are writable or executable,
1179   // so that is how we search for them.
1180   // Large data sections also go into their own PT_LOAD segment.
1181   // People who need segments sorted on some other basis will
1182   // have to use a linker script.
1183
1184   Segment_list::const_iterator p;
1185   for (p = this->segment_list_.begin();
1186        p != this->segment_list_.end();
1187        ++p)
1188     {
1189       if ((*p)->type() != elfcpp::PT_LOAD)
1190         continue;
1191       if (!parameters->options().omagic()
1192           && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1193         continue;
1194       if (parameters->options().rosegment()
1195           && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1196         continue;
1197       // If -Tbss was specified, we need to separate the data and BSS
1198       // segments.
1199       if (parameters->options().user_set_Tbss())
1200         {
1201           if ((os->type() == elfcpp::SHT_NOBITS)
1202               == (*p)->has_any_data_sections())
1203             continue;
1204         }
1205       if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1206         continue;
1207
1208       if (is_address_set)
1209         {
1210           if ((*p)->are_addresses_set())
1211             continue;
1212
1213           (*p)->add_initial_output_data(os);
1214           (*p)->update_flags_for_output_section(seg_flags);
1215           (*p)->set_addresses(addr, addr);
1216           break;
1217         }
1218
1219       (*p)->add_output_section_to_load(this, os, seg_flags);
1220       break;
1221     }
1222
1223   if (p == this->segment_list_.end())
1224     {
1225       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1226                                                        seg_flags);
1227       if (os->is_large_data_section())
1228         oseg->set_is_large_data_segment();
1229       oseg->add_output_section_to_load(this, os, seg_flags);
1230       if (is_address_set)
1231         oseg->set_addresses(addr, addr);
1232     }
1233
1234   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1235   // segment.
1236   if (os->type() == elfcpp::SHT_NOTE)
1237     {
1238       // See if we already have an equivalent PT_NOTE segment.
1239       for (p = this->segment_list_.begin();
1240            p != segment_list_.end();
1241            ++p)
1242         {
1243           if ((*p)->type() == elfcpp::PT_NOTE
1244               && (((*p)->flags() & elfcpp::PF_W)
1245                   == (seg_flags & elfcpp::PF_W)))
1246             {
1247               (*p)->add_output_section_to_nonload(os, seg_flags);
1248               break;
1249             }
1250         }
1251
1252       if (p == this->segment_list_.end())
1253         {
1254           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1255                                                            seg_flags);
1256           oseg->add_output_section_to_nonload(os, seg_flags);
1257         }
1258     }
1259
1260   // If we see a loadable SHF_TLS section, we create a PT_TLS
1261   // segment.  There can only be one such segment.
1262   if ((flags & elfcpp::SHF_TLS) != 0)
1263     {
1264       if (this->tls_segment_ == NULL)
1265         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1266       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1267     }
1268
1269   // If -z relro is in effect, and we see a relro section, we create a
1270   // PT_GNU_RELRO segment.  There can only be one such segment.
1271   if (os->is_relro() && parameters->options().relro())
1272     {
1273       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1274       if (this->relro_segment_ == NULL)
1275         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1276       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1277     }
1278 }
1279
1280 // Make an output section for a script.
1281
1282 Output_section*
1283 Layout::make_output_section_for_script(
1284     const char* name,
1285     Script_sections::Section_type section_type)
1286 {
1287   name = this->namepool_.add(name, false, NULL);
1288   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1289   if (section_type == Script_sections::ST_NOLOAD)
1290     sh_flags = 0;
1291   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1292                                                  sh_flags, ORDER_INVALID,
1293                                                  false);
1294   os->set_found_in_sections_clause();
1295   if (section_type == Script_sections::ST_NOLOAD)
1296     os->set_is_noload();
1297   return os;
1298 }
1299
1300 // Return the number of segments we expect to see.
1301
1302 size_t
1303 Layout::expected_segment_count() const
1304 {
1305   size_t ret = this->segment_list_.size();
1306
1307   // If we didn't see a SECTIONS clause in a linker script, we should
1308   // already have the complete list of segments.  Otherwise we ask the
1309   // SECTIONS clause how many segments it expects, and add in the ones
1310   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1311
1312   if (!this->script_options_->saw_sections_clause())
1313     return ret;
1314   else
1315     {
1316       const Script_sections* ss = this->script_options_->script_sections();
1317       return ret + ss->expected_segment_count(this);
1318     }
1319 }
1320
1321 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
1322 // is whether we saw a .note.GNU-stack section in the object file.
1323 // GNU_STACK_FLAGS is the section flags.  The flags give the
1324 // protection required for stack memory.  We record this in an
1325 // executable as a PT_GNU_STACK segment.  If an object file does not
1326 // have a .note.GNU-stack segment, we must assume that it is an old
1327 // object.  On some targets that will force an executable stack.
1328
1329 void
1330 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
1331 {
1332   if (!seen_gnu_stack)
1333     this->input_without_gnu_stack_note_ = true;
1334   else
1335     {
1336       this->input_with_gnu_stack_note_ = true;
1337       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1338         this->input_requires_executable_stack_ = true;
1339     }
1340 }
1341
1342 // Create automatic note sections.
1343
1344 void
1345 Layout::create_notes()
1346 {
1347   this->create_gold_note();
1348   this->create_executable_stack_info();
1349   this->create_build_id();
1350 }
1351
1352 // Create the dynamic sections which are needed before we read the
1353 // relocs.
1354
1355 void
1356 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1357 {
1358   if (parameters->doing_static_link())
1359     return;
1360
1361   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1362                                                        elfcpp::SHT_DYNAMIC,
1363                                                        (elfcpp::SHF_ALLOC
1364                                                         | elfcpp::SHF_WRITE),
1365                                                        false, ORDER_RELRO,
1366                                                        true);
1367
1368   this->dynamic_symbol_ =
1369     symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
1370                                   this->dynamic_section_, 0, 0,
1371                                   elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1372                                   elfcpp::STV_HIDDEN, 0, false, false);
1373
1374   this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
1375
1376   this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1377 }
1378
1379 // For each output section whose name can be represented as C symbol,
1380 // define __start and __stop symbols for the section.  This is a GNU
1381 // extension.
1382
1383 void
1384 Layout::define_section_symbols(Symbol_table* symtab)
1385 {
1386   for (Section_list::const_iterator p = this->section_list_.begin();
1387        p != this->section_list_.end();
1388        ++p)
1389     {
1390       const char* const name = (*p)->name();
1391       if (is_cident(name))
1392         {
1393           const std::string name_string(name);
1394           const std::string start_name(cident_section_start_prefix
1395                                        + name_string);
1396           const std::string stop_name(cident_section_stop_prefix
1397                                       + name_string);
1398
1399           symtab->define_in_output_data(start_name.c_str(),
1400                                         NULL, // version
1401                                         Symbol_table::PREDEFINED,
1402                                         *p,
1403                                         0, // value
1404                                         0, // symsize
1405                                         elfcpp::STT_NOTYPE,
1406                                         elfcpp::STB_GLOBAL,
1407                                         elfcpp::STV_DEFAULT,
1408                                         0, // nonvis
1409                                         false, // offset_is_from_end
1410                                         true); // only_if_ref
1411
1412           symtab->define_in_output_data(stop_name.c_str(),
1413                                         NULL, // version
1414                                         Symbol_table::PREDEFINED,
1415                                         *p,
1416                                         0, // value
1417                                         0, // symsize
1418                                         elfcpp::STT_NOTYPE,
1419                                         elfcpp::STB_GLOBAL,
1420                                         elfcpp::STV_DEFAULT,
1421                                         0, // nonvis
1422                                         true, // offset_is_from_end
1423                                         true); // only_if_ref
1424         }
1425     }
1426 }
1427
1428 // Define symbols for group signatures.
1429
1430 void
1431 Layout::define_group_signatures(Symbol_table* symtab)
1432 {
1433   for (Group_signatures::iterator p = this->group_signatures_.begin();
1434        p != this->group_signatures_.end();
1435        ++p)
1436     {
1437       Symbol* sym = symtab->lookup(p->signature, NULL);
1438       if (sym != NULL)
1439         p->section->set_info_symndx(sym);
1440       else
1441         {
1442           // Force the name of the group section to the group
1443           // signature, and use the group's section symbol as the
1444           // signature symbol.
1445           if (strcmp(p->section->name(), p->signature) != 0)
1446             {
1447               const char* name = this->namepool_.add(p->signature,
1448                                                      true, NULL);
1449               p->section->set_name(name);
1450             }
1451           p->section->set_needs_symtab_index();
1452           p->section->set_info_section_symndx(p->section);
1453         }
1454     }
1455
1456   this->group_signatures_.clear();
1457 }
1458
1459 // Find the first read-only PT_LOAD segment, creating one if
1460 // necessary.
1461
1462 Output_segment*
1463 Layout::find_first_load_seg()
1464 {
1465   Output_segment* best = NULL;
1466   for (Segment_list::const_iterator p = this->segment_list_.begin();
1467        p != this->segment_list_.end();
1468        ++p)
1469     {
1470       if ((*p)->type() == elfcpp::PT_LOAD
1471           && ((*p)->flags() & elfcpp::PF_R) != 0
1472           && (parameters->options().omagic()
1473               || ((*p)->flags() & elfcpp::PF_W) == 0))
1474         {
1475           if (best == NULL || this->segment_precedes(*p, best))
1476             best = *p;
1477         }
1478     }
1479   if (best != NULL)
1480     return best;
1481
1482   gold_assert(!this->script_options_->saw_phdrs_clause());
1483
1484   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1485                                                        elfcpp::PF_R);
1486   return load_seg;
1487 }
1488
1489 // Save states of all current output segments.  Store saved states
1490 // in SEGMENT_STATES.
1491
1492 void
1493 Layout::save_segments(Segment_states* segment_states)
1494 {
1495   for (Segment_list::const_iterator p = this->segment_list_.begin();
1496        p != this->segment_list_.end();
1497        ++p)
1498     {
1499       Output_segment* segment = *p;
1500       // Shallow copy.
1501       Output_segment* copy = new Output_segment(*segment);
1502       (*segment_states)[segment] = copy;
1503     }
1504 }
1505
1506 // Restore states of output segments and delete any segment not found in
1507 // SEGMENT_STATES.
1508
1509 void
1510 Layout::restore_segments(const Segment_states* segment_states)
1511 {
1512   // Go through the segment list and remove any segment added in the
1513   // relaxation loop.
1514   this->tls_segment_ = NULL;
1515   this->relro_segment_ = NULL;
1516   Segment_list::iterator list_iter = this->segment_list_.begin();
1517   while (list_iter != this->segment_list_.end())
1518     {
1519       Output_segment* segment = *list_iter;
1520       Segment_states::const_iterator states_iter =
1521           segment_states->find(segment);
1522       if (states_iter != segment_states->end())
1523         {
1524           const Output_segment* copy = states_iter->second;
1525           // Shallow copy to restore states.
1526           *segment = *copy;
1527
1528           // Also fix up TLS and RELRO segment pointers as appropriate.
1529           if (segment->type() == elfcpp::PT_TLS)
1530             this->tls_segment_ = segment;
1531           else if (segment->type() == elfcpp::PT_GNU_RELRO)
1532             this->relro_segment_ = segment;
1533
1534           ++list_iter;
1535         }
1536       else
1537         {
1538           list_iter = this->segment_list_.erase(list_iter);
1539           // This is a segment created during section layout.  It should be
1540           // safe to remove it since we should have removed all pointers to it.
1541           delete segment;
1542         }
1543     }
1544 }
1545
1546 // Clean up after relaxation so that sections can be laid out again.
1547
1548 void
1549 Layout::clean_up_after_relaxation()
1550 {
1551   // Restore the segments to point state just prior to the relaxation loop.
1552   Script_sections* script_section = this->script_options_->script_sections();
1553   script_section->release_segments();
1554   this->restore_segments(this->segment_states_);
1555
1556   // Reset section addresses and file offsets
1557   for (Section_list::iterator p = this->section_list_.begin();
1558        p != this->section_list_.end();
1559        ++p)
1560     {
1561       (*p)->restore_states();
1562
1563       // If an input section changes size because of relaxation,
1564       // we need to adjust the section offsets of all input sections.
1565       // after such a section.
1566       if ((*p)->section_offsets_need_adjustment())
1567         (*p)->adjust_section_offsets();
1568
1569       (*p)->reset_address_and_file_offset();
1570     }
1571
1572   // Reset special output object address and file offsets.
1573   for (Data_list::iterator p = this->special_output_list_.begin();
1574        p != this->special_output_list_.end();
1575        ++p)
1576     (*p)->reset_address_and_file_offset();
1577
1578   // A linker script may have created some output section data objects.
1579   // They are useless now.
1580   for (Output_section_data_list::const_iterator p =
1581          this->script_output_section_data_list_.begin();
1582        p != this->script_output_section_data_list_.end();
1583        ++p)
1584     delete *p;
1585   this->script_output_section_data_list_.clear();
1586 }
1587
1588 // Prepare for relaxation.
1589
1590 void
1591 Layout::prepare_for_relaxation()
1592 {
1593   // Create an relaxation debug check if in debugging mode.
1594   if (is_debugging_enabled(DEBUG_RELAXATION))
1595     this->relaxation_debug_check_ = new Relaxation_debug_check();
1596
1597   // Save segment states.
1598   this->segment_states_ = new Segment_states();
1599   this->save_segments(this->segment_states_);
1600
1601   for(Section_list::const_iterator p = this->section_list_.begin();
1602       p != this->section_list_.end();
1603       ++p)
1604     (*p)->save_states();
1605
1606   if (is_debugging_enabled(DEBUG_RELAXATION))
1607     this->relaxation_debug_check_->check_output_data_for_reset_values(
1608         this->section_list_, this->special_output_list_);
1609
1610   // Also enable recording of output section data from scripts.
1611   this->record_output_section_data_from_script_ = true;
1612 }
1613
1614 // Relaxation loop body:  If target has no relaxation, this runs only once
1615 // Otherwise, the target relaxation hook is called at the end of
1616 // each iteration.  If the hook returns true, it means re-layout of
1617 // section is required.
1618 //
1619 // The number of segments created by a linking script without a PHDRS
1620 // clause may be affected by section sizes and alignments.  There is
1621 // a remote chance that relaxation causes different number of PT_LOAD
1622 // segments are created and sections are attached to different segments.
1623 // Therefore, we always throw away all segments created during section
1624 // layout.  In order to be able to restart the section layout, we keep
1625 // a copy of the segment list right before the relaxation loop and use
1626 // that to restore the segments.
1627 //
1628 // PASS is the current relaxation pass number.
1629 // SYMTAB is a symbol table.
1630 // PLOAD_SEG is the address of a pointer for the load segment.
1631 // PHDR_SEG is a pointer to the PHDR segment.
1632 // SEGMENT_HEADERS points to the output segment header.
1633 // FILE_HEADER points to the output file header.
1634 // PSHNDX is the address to store the output section index.
1635
1636 off_t inline
1637 Layout::relaxation_loop_body(
1638     int pass,
1639     Target* target,
1640     Symbol_table* symtab,
1641     Output_segment** pload_seg,
1642     Output_segment* phdr_seg,
1643     Output_segment_headers* segment_headers,
1644     Output_file_header* file_header,
1645     unsigned int* pshndx)
1646 {
1647   // If this is not the first iteration, we need to clean up after
1648   // relaxation so that we can lay out the sections again.
1649   if (pass != 0)
1650     this->clean_up_after_relaxation();
1651
1652   // If there is a SECTIONS clause, put all the input sections into
1653   // the required order.
1654   Output_segment* load_seg;
1655   if (this->script_options_->saw_sections_clause())
1656     load_seg = this->set_section_addresses_from_script(symtab);
1657   else if (parameters->options().relocatable())
1658     load_seg = NULL;
1659   else
1660     load_seg = this->find_first_load_seg();
1661
1662   if (parameters->options().oformat_enum()
1663       != General_options::OBJECT_FORMAT_ELF)
1664     load_seg = NULL;
1665
1666   // If the user set the address of the text segment, that may not be
1667   // compatible with putting the segment headers and file headers into
1668   // that segment.
1669   if (parameters->options().user_set_Ttext())
1670     load_seg = NULL;
1671
1672   gold_assert(phdr_seg == NULL
1673               || load_seg != NULL
1674               || this->script_options_->saw_sections_clause());
1675
1676   // If the address of the load segment we found has been set by
1677   // --section-start rather than by a script, then adjust the VMA and
1678   // LMA downward if possible to include the file and section headers.
1679   uint64_t header_gap = 0;
1680   if (load_seg != NULL
1681       && load_seg->are_addresses_set()
1682       && !this->script_options_->saw_sections_clause()
1683       && !parameters->options().relocatable())
1684     {
1685       file_header->finalize_data_size();
1686       segment_headers->finalize_data_size();
1687       size_t sizeof_headers = (file_header->data_size()
1688                                + segment_headers->data_size());
1689       const uint64_t abi_pagesize = target->abi_pagesize();
1690       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
1691       hdr_paddr &= ~(abi_pagesize - 1);
1692       uint64_t subtract = load_seg->paddr() - hdr_paddr;
1693       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
1694         load_seg = NULL;
1695       else
1696         {
1697           load_seg->set_addresses(load_seg->vaddr() - subtract,
1698                                   load_seg->paddr() - subtract);
1699           header_gap = subtract - sizeof_headers;
1700         }
1701     }
1702
1703   // Lay out the segment headers.
1704   if (!parameters->options().relocatable())
1705     {
1706       gold_assert(segment_headers != NULL);
1707       if (header_gap != 0 && load_seg != NULL)
1708         {
1709           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
1710           load_seg->add_initial_output_data(z);
1711         }
1712       if (load_seg != NULL)
1713         load_seg->add_initial_output_data(segment_headers);
1714       if (phdr_seg != NULL)
1715         phdr_seg->add_initial_output_data(segment_headers);
1716     }
1717
1718   // Lay out the file header.
1719   if (load_seg != NULL)
1720     load_seg->add_initial_output_data(file_header);
1721
1722   if (this->script_options_->saw_phdrs_clause()
1723       && !parameters->options().relocatable())
1724     {
1725       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1726       // clause in a linker script.
1727       Script_sections* ss = this->script_options_->script_sections();
1728       ss->put_headers_in_phdrs(file_header, segment_headers);
1729     }
1730
1731   // We set the output section indexes in set_segment_offsets and
1732   // set_section_indexes.
1733   *pshndx = 1;
1734
1735   // Set the file offsets of all the segments, and all the sections
1736   // they contain.
1737   off_t off;
1738   if (!parameters->options().relocatable())
1739     off = this->set_segment_offsets(target, load_seg, pshndx);
1740   else
1741     off = this->set_relocatable_section_offsets(file_header, pshndx);
1742
1743    // Verify that the dummy relaxation does not change anything.
1744   if (is_debugging_enabled(DEBUG_RELAXATION))
1745     {
1746       if (pass == 0)
1747         this->relaxation_debug_check_->read_sections(this->section_list_);
1748       else
1749         this->relaxation_debug_check_->verify_sections(this->section_list_);
1750     }
1751
1752   *pload_seg = load_seg;
1753   return off;
1754 }
1755
1756 // Search the list of patterns and find the postion of the given section
1757 // name in the output section.  If the section name matches a glob
1758 // pattern and a non-glob name, then the non-glob position takes
1759 // precedence.  Return 0 if no match is found.
1760
1761 unsigned int
1762 Layout::find_section_order_index(const std::string& section_name)
1763 {
1764   Unordered_map<std::string, unsigned int>::iterator map_it;
1765   map_it = this->input_section_position_.find(section_name);
1766   if (map_it != this->input_section_position_.end())
1767     return map_it->second;
1768
1769   // Absolute match failed.  Linear search the glob patterns.
1770   std::vector<std::string>::iterator it;
1771   for (it = this->input_section_glob_.begin();
1772        it != this->input_section_glob_.end();
1773        ++it)
1774     {
1775        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
1776          {
1777            map_it = this->input_section_position_.find(*it);
1778            gold_assert(map_it != this->input_section_position_.end());
1779            return map_it->second;
1780          }
1781     }
1782   return 0;
1783 }
1784
1785 // Read the sequence of input sections from the file specified with
1786 // --section-ordering-file.
1787
1788 void
1789 Layout::read_layout_from_file()
1790 {
1791   const char* filename = parameters->options().section_ordering_file();
1792   std::ifstream in;
1793   std::string line;
1794
1795   in.open(filename);
1796   if (!in)
1797     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
1798                filename, strerror(errno));
1799
1800   std::getline(in, line);   // this chops off the trailing \n, if any
1801   unsigned int position = 1;
1802
1803   while (in)
1804     {
1805       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
1806         line.resize(line.length() - 1);
1807       // Ignore comments, beginning with '#'
1808       if (line[0] == '#')
1809         {
1810           std::getline(in, line);
1811           continue;
1812         }
1813       this->input_section_position_[line] = position;
1814       // Store all glob patterns in a vector.
1815       if (is_wildcard_string(line.c_str()))
1816         this->input_section_glob_.push_back(line);
1817       position++;
1818       std::getline(in, line);
1819     }
1820 }
1821
1822 // Finalize the layout.  When this is called, we have created all the
1823 // output sections and all the output segments which are based on
1824 // input sections.  We have several things to do, and we have to do
1825 // them in the right order, so that we get the right results correctly
1826 // and efficiently.
1827
1828 // 1) Finalize the list of output segments and create the segment
1829 // table header.
1830
1831 // 2) Finalize the dynamic symbol table and associated sections.
1832
1833 // 3) Determine the final file offset of all the output segments.
1834
1835 // 4) Determine the final file offset of all the SHF_ALLOC output
1836 // sections.
1837
1838 // 5) Create the symbol table sections and the section name table
1839 // section.
1840
1841 // 6) Finalize the symbol table: set symbol values to their final
1842 // value and make a final determination of which symbols are going
1843 // into the output symbol table.
1844
1845 // 7) Create the section table header.
1846
1847 // 8) Determine the final file offset of all the output sections which
1848 // are not SHF_ALLOC, including the section table header.
1849
1850 // 9) Finalize the ELF file header.
1851
1852 // This function returns the size of the output file.
1853
1854 off_t
1855 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
1856                  Target* target, const Task* task)
1857 {
1858   target->finalize_sections(this, input_objects, symtab);
1859
1860   this->count_local_symbols(task, input_objects);
1861
1862   this->link_stabs_sections();
1863
1864   Output_segment* phdr_seg = NULL;
1865   if (!parameters->options().relocatable() && !parameters->doing_static_link())
1866     {
1867       // There was a dynamic object in the link.  We need to create
1868       // some information for the dynamic linker.
1869
1870       // Create the PT_PHDR segment which will hold the program
1871       // headers.
1872       if (!this->script_options_->saw_phdrs_clause())
1873         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
1874
1875       // Create the dynamic symbol table, including the hash table.
1876       Output_section* dynstr;
1877       std::vector<Symbol*> dynamic_symbols;
1878       unsigned int local_dynamic_count;
1879       Versions versions(*this->script_options()->version_script_info(),
1880                         &this->dynpool_);
1881       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
1882                                   &local_dynamic_count, &dynamic_symbols,
1883                                   &versions);
1884
1885       // Create the .interp section to hold the name of the
1886       // interpreter, and put it in a PT_INTERP segment.
1887       if (!parameters->options().shared())
1888         this->create_interp(target);
1889
1890       // Finish the .dynamic section to hold the dynamic data, and put
1891       // it in a PT_DYNAMIC segment.
1892       this->finish_dynamic_section(input_objects, symtab);
1893
1894       // We should have added everything we need to the dynamic string
1895       // table.
1896       this->dynpool_.set_string_offsets();
1897
1898       // Create the version sections.  We can't do this until the
1899       // dynamic string table is complete.
1900       this->create_version_sections(&versions, symtab, local_dynamic_count,
1901                                     dynamic_symbols, dynstr);
1902
1903       // Set the size of the _DYNAMIC symbol.  We can't do this until
1904       // after we call create_version_sections.
1905       this->set_dynamic_symbol_size(symtab);
1906     }
1907
1908   // Create segment headers.
1909   Output_segment_headers* segment_headers =
1910     (parameters->options().relocatable()
1911      ? NULL
1912      : new Output_segment_headers(this->segment_list_));
1913
1914   // Lay out the file header.
1915   Output_file_header* file_header
1916     = new Output_file_header(target, symtab, segment_headers,
1917                              parameters->options().entry());
1918
1919   this->special_output_list_.push_back(file_header);
1920   if (segment_headers != NULL)
1921     this->special_output_list_.push_back(segment_headers);
1922
1923   // Find approriate places for orphan output sections if we are using
1924   // a linker script.
1925   if (this->script_options_->saw_sections_clause())
1926     this->place_orphan_sections_in_script();
1927
1928   Output_segment* load_seg;
1929   off_t off;
1930   unsigned int shndx;
1931   int pass = 0;
1932
1933   // Take a snapshot of the section layout as needed.
1934   if (target->may_relax())
1935     this->prepare_for_relaxation();
1936
1937   // Run the relaxation loop to lay out sections.
1938   do
1939     {
1940       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
1941                                        phdr_seg, segment_headers, file_header,
1942                                        &shndx);
1943       pass++;
1944     }
1945   while (target->may_relax()
1946          && target->relax(pass, input_objects, symtab, this, task));
1947
1948   // Set the file offsets of all the non-data sections we've seen so
1949   // far which don't have to wait for the input sections.  We need
1950   // this in order to finalize local symbols in non-allocated
1951   // sections.
1952   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1953
1954   // Set the section indexes of all unallocated sections seen so far,
1955   // in case any of them are somehow referenced by a symbol.
1956   shndx = this->set_section_indexes(shndx);
1957
1958   // Create the symbol table sections.
1959   this->create_symtab_sections(input_objects, symtab, shndx, &off);
1960   if (!parameters->doing_static_link())
1961     this->assign_local_dynsym_offsets(input_objects);
1962
1963   // Process any symbol assignments from a linker script.  This must
1964   // be called after the symbol table has been finalized.
1965   this->script_options_->finalize_symbols(symtab, this);
1966
1967   // Create the incremental inputs sections.
1968   if (this->incremental_inputs_)
1969     {
1970       this->incremental_inputs_->finalize();
1971       this->create_incremental_info_sections(symtab);
1972     }
1973
1974   // Create the .shstrtab section.
1975   Output_section* shstrtab_section = this->create_shstrtab();
1976
1977   // Set the file offsets of the rest of the non-data sections which
1978   // don't have to wait for the input sections.
1979   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1980
1981   // Now that all sections have been created, set the section indexes
1982   // for any sections which haven't been done yet.
1983   shndx = this->set_section_indexes(shndx);
1984
1985   // Create the section table header.
1986   this->create_shdrs(shstrtab_section, &off);
1987
1988   // If there are no sections which require postprocessing, we can
1989   // handle the section names now, and avoid a resize later.
1990   if (!this->any_postprocessing_sections_)
1991     {
1992       off = this->set_section_offsets(off,
1993                                       POSTPROCESSING_SECTIONS_PASS);
1994       off =
1995           this->set_section_offsets(off,
1996                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1997     }
1998
1999   file_header->set_section_info(this->section_headers_, shstrtab_section);
2000
2001   // Now we know exactly where everything goes in the output file
2002   // (except for non-allocated sections which require postprocessing).
2003   Output_data::layout_complete();
2004
2005   this->output_file_size_ = off;
2006
2007   return off;
2008 }
2009
2010 // Create a note header following the format defined in the ELF ABI.
2011 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2012 // of the section to create, DESCSZ is the size of the descriptor.
2013 // ALLOCATE is true if the section should be allocated in memory.
2014 // This returns the new note section.  It sets *TRAILING_PADDING to
2015 // the number of trailing zero bytes required.
2016
2017 Output_section*
2018 Layout::create_note(const char* name, int note_type,
2019                     const char* section_name, size_t descsz,
2020                     bool allocate, size_t* trailing_padding)
2021 {
2022   // Authorities all agree that the values in a .note field should
2023   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
2024   // they differ on what the alignment is for 64-bit binaries.
2025   // The GABI says unambiguously they take 8-byte alignment:
2026   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2027   // Other documentation says alignment should always be 4 bytes:
2028   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2029   // GNU ld and GNU readelf both support the latter (at least as of
2030   // version 2.16.91), and glibc always generates the latter for
2031   // .note.ABI-tag (as of version 1.6), so that's the one we go with
2032   // here.
2033 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
2034   const int size = parameters->target().get_size();
2035 #else
2036   const int size = 32;
2037 #endif
2038
2039   // The contents of the .note section.
2040   size_t namesz = strlen(name) + 1;
2041   size_t aligned_namesz = align_address(namesz, size / 8);
2042   size_t aligned_descsz = align_address(descsz, size / 8);
2043
2044   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2045
2046   unsigned char* buffer = new unsigned char[notehdrsz];
2047   memset(buffer, 0, notehdrsz);
2048
2049   bool is_big_endian = parameters->target().is_big_endian();
2050
2051   if (size == 32)
2052     {
2053       if (!is_big_endian)
2054         {
2055           elfcpp::Swap<32, false>::writeval(buffer, namesz);
2056           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2057           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2058         }
2059       else
2060         {
2061           elfcpp::Swap<32, true>::writeval(buffer, namesz);
2062           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2063           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2064         }
2065     }
2066   else if (size == 64)
2067     {
2068       if (!is_big_endian)
2069         {
2070           elfcpp::Swap<64, false>::writeval(buffer, namesz);
2071           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2072           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2073         }
2074       else
2075         {
2076           elfcpp::Swap<64, true>::writeval(buffer, namesz);
2077           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2078           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2079         }
2080     }
2081   else
2082     gold_unreachable();
2083
2084   memcpy(buffer + 3 * (size / 8), name, namesz);
2085
2086   elfcpp::Elf_Xword flags = 0;
2087   Output_section_order order = ORDER_INVALID;
2088   if (allocate)
2089     {
2090       flags = elfcpp::SHF_ALLOC;
2091       order = ORDER_RO_NOTE;
2092     }
2093   Output_section* os = this->choose_output_section(NULL, section_name,
2094                                                    elfcpp::SHT_NOTE,
2095                                                    flags, false, order, false);
2096   if (os == NULL)
2097     return NULL;
2098
2099   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2100                                                            size / 8,
2101                                                            "** note header");
2102   os->add_output_section_data(posd);
2103
2104   *trailing_padding = aligned_descsz - descsz;
2105
2106   return os;
2107 }
2108
2109 // For an executable or shared library, create a note to record the
2110 // version of gold used to create the binary.
2111
2112 void
2113 Layout::create_gold_note()
2114 {
2115   if (parameters->options().relocatable())
2116     return;
2117
2118   std::string desc = std::string("gold ") + gold::get_version_string();
2119
2120   size_t trailing_padding;
2121   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2122                                          ".note.gnu.gold-version", desc.size(),
2123                                          false, &trailing_padding);
2124   if (os == NULL)
2125     return;
2126
2127   Output_section_data* posd = new Output_data_const(desc, 4);
2128   os->add_output_section_data(posd);
2129
2130   if (trailing_padding > 0)
2131     {
2132       posd = new Output_data_zero_fill(trailing_padding, 0);
2133       os->add_output_section_data(posd);
2134     }
2135 }
2136
2137 // Record whether the stack should be executable.  This can be set
2138 // from the command line using the -z execstack or -z noexecstack
2139 // options.  Otherwise, if any input file has a .note.GNU-stack
2140 // section with the SHF_EXECINSTR flag set, the stack should be
2141 // executable.  Otherwise, if at least one input file a
2142 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2143 // section, we use the target default for whether the stack should be
2144 // executable.  Otherwise, we don't generate a stack note.  When
2145 // generating a object file, we create a .note.GNU-stack section with
2146 // the appropriate marking.  When generating an executable or shared
2147 // library, we create a PT_GNU_STACK segment.
2148
2149 void
2150 Layout::create_executable_stack_info()
2151 {
2152   bool is_stack_executable;
2153   if (parameters->options().is_execstack_set())
2154     is_stack_executable = parameters->options().is_stack_executable();
2155   else if (!this->input_with_gnu_stack_note_)
2156     return;
2157   else
2158     {
2159       if (this->input_requires_executable_stack_)
2160         is_stack_executable = true;
2161       else if (this->input_without_gnu_stack_note_)
2162         is_stack_executable =
2163           parameters->target().is_default_stack_executable();
2164       else
2165         is_stack_executable = false;
2166     }
2167
2168   if (parameters->options().relocatable())
2169     {
2170       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2171       elfcpp::Elf_Xword flags = 0;
2172       if (is_stack_executable)
2173         flags |= elfcpp::SHF_EXECINSTR;
2174       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2175                                 ORDER_INVALID, false);
2176     }
2177   else
2178     {
2179       if (this->script_options_->saw_phdrs_clause())
2180         return;
2181       int flags = elfcpp::PF_R | elfcpp::PF_W;
2182       if (is_stack_executable)
2183         flags |= elfcpp::PF_X;
2184       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2185     }
2186 }
2187
2188 // If --build-id was used, set up the build ID note.
2189
2190 void
2191 Layout::create_build_id()
2192 {
2193   if (!parameters->options().user_set_build_id())
2194     return;
2195
2196   const char* style = parameters->options().build_id();
2197   if (strcmp(style, "none") == 0)
2198     return;
2199
2200   // Set DESCSZ to the size of the note descriptor.  When possible,
2201   // set DESC to the note descriptor contents.
2202   size_t descsz;
2203   std::string desc;
2204   if (strcmp(style, "md5") == 0)
2205     descsz = 128 / 8;
2206   else if (strcmp(style, "sha1") == 0)
2207     descsz = 160 / 8;
2208   else if (strcmp(style, "uuid") == 0)
2209     {
2210       const size_t uuidsz = 128 / 8;
2211
2212       char buffer[uuidsz];
2213       memset(buffer, 0, uuidsz);
2214
2215       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2216       if (descriptor < 0)
2217         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2218                    strerror(errno));
2219       else
2220         {
2221           ssize_t got = ::read(descriptor, buffer, uuidsz);
2222           release_descriptor(descriptor, true);
2223           if (got < 0)
2224             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2225           else if (static_cast<size_t>(got) != uuidsz)
2226             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2227                        uuidsz, got);
2228         }
2229
2230       desc.assign(buffer, uuidsz);
2231       descsz = uuidsz;
2232     }
2233   else if (strncmp(style, "0x", 2) == 0)
2234     {
2235       hex_init();
2236       const char* p = style + 2;
2237       while (*p != '\0')
2238         {
2239           if (hex_p(p[0]) && hex_p(p[1]))
2240             {
2241               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2242               desc += c;
2243               p += 2;
2244             }
2245           else if (*p == '-' || *p == ':')
2246             ++p;
2247           else
2248             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2249                        style);
2250         }
2251       descsz = desc.size();
2252     }
2253   else
2254     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2255
2256   // Create the note.
2257   size_t trailing_padding;
2258   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2259                                          ".note.gnu.build-id", descsz, true,
2260                                          &trailing_padding);
2261   if (os == NULL)
2262     return;
2263
2264   if (!desc.empty())
2265     {
2266       // We know the value already, so we fill it in now.
2267       gold_assert(desc.size() == descsz);
2268
2269       Output_section_data* posd = new Output_data_const(desc, 4);
2270       os->add_output_section_data(posd);
2271
2272       if (trailing_padding != 0)
2273         {
2274           posd = new Output_data_zero_fill(trailing_padding, 0);
2275           os->add_output_section_data(posd);
2276         }
2277     }
2278   else
2279     {
2280       // We need to compute a checksum after we have completed the
2281       // link.
2282       gold_assert(trailing_padding == 0);
2283       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2284       os->add_output_section_data(this->build_id_note_);
2285     }
2286 }
2287
2288 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2289 // field of the former should point to the latter.  I'm not sure who
2290 // started this, but the GNU linker does it, and some tools depend
2291 // upon it.
2292
2293 void
2294 Layout::link_stabs_sections()
2295 {
2296   if (!this->have_stabstr_section_)
2297     return;
2298
2299   for (Section_list::iterator p = this->section_list_.begin();
2300        p != this->section_list_.end();
2301        ++p)
2302     {
2303       if ((*p)->type() != elfcpp::SHT_STRTAB)
2304         continue;
2305
2306       const char* name = (*p)->name();
2307       if (strncmp(name, ".stab", 5) != 0)
2308         continue;
2309
2310       size_t len = strlen(name);
2311       if (strcmp(name + len - 3, "str") != 0)
2312         continue;
2313
2314       std::string stab_name(name, len - 3);
2315       Output_section* stab_sec;
2316       stab_sec = this->find_output_section(stab_name.c_str());
2317       if (stab_sec != NULL)
2318         stab_sec->set_link_section(*p);
2319     }
2320 }
2321
2322 // Create .gnu_incremental_inputs and related sections needed
2323 // for the next run of incremental linking to check what has changed.
2324
2325 void
2326 Layout::create_incremental_info_sections(Symbol_table* symtab)
2327 {
2328   Incremental_inputs* incr = this->incremental_inputs_;
2329
2330   gold_assert(incr != NULL);
2331
2332   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2333   incr->create_data_sections(symtab);
2334
2335   // Add the .gnu_incremental_inputs section.
2336   const char* incremental_inputs_name =
2337     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2338   Output_section* incremental_inputs_os =
2339     this->make_output_section(incremental_inputs_name,
2340                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2341                               ORDER_INVALID, false);
2342   incremental_inputs_os->add_output_section_data(incr->inputs_section());
2343
2344   // Add the .gnu_incremental_symtab section.
2345   const char* incremental_symtab_name =
2346     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2347   Output_section* incremental_symtab_os =
2348     this->make_output_section(incremental_symtab_name,
2349                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2350                               ORDER_INVALID, false);
2351   incremental_symtab_os->add_output_section_data(incr->symtab_section());
2352   incremental_symtab_os->set_entsize(4);
2353
2354   // Add the .gnu_incremental_relocs section.
2355   const char* incremental_relocs_name =
2356     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2357   Output_section* incremental_relocs_os =
2358     this->make_output_section(incremental_relocs_name,
2359                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2360                               ORDER_INVALID, false);
2361   incremental_relocs_os->add_output_section_data(incr->relocs_section());
2362   incremental_relocs_os->set_entsize(incr->relocs_entsize());
2363
2364   // Add the .gnu_incremental_got_plt section.
2365   const char* incremental_got_plt_name =
2366     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2367   Output_section* incremental_got_plt_os =
2368     this->make_output_section(incremental_got_plt_name,
2369                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2370                               ORDER_INVALID, false);
2371   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2372
2373   // Add the .gnu_incremental_strtab section.
2374   const char* incremental_strtab_name =
2375     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2376   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2377                                                         elfcpp::SHT_STRTAB, 0,
2378                                                         ORDER_INVALID, false);
2379   Output_data_strtab* strtab_data =
2380       new Output_data_strtab(incr->get_stringpool());
2381   incremental_strtab_os->add_output_section_data(strtab_data);
2382
2383   incremental_inputs_os->set_after_input_sections();
2384   incremental_symtab_os->set_after_input_sections();
2385   incremental_relocs_os->set_after_input_sections();
2386   incremental_got_plt_os->set_after_input_sections();
2387
2388   incremental_inputs_os->set_link_section(incremental_strtab_os);
2389   incremental_symtab_os->set_link_section(incremental_inputs_os);
2390   incremental_relocs_os->set_link_section(incremental_inputs_os);
2391   incremental_got_plt_os->set_link_section(incremental_inputs_os);
2392 }
2393
2394 // Return whether SEG1 should be before SEG2 in the output file.  This
2395 // is based entirely on the segment type and flags.  When this is
2396 // called the segment addresses has normally not yet been set.
2397
2398 bool
2399 Layout::segment_precedes(const Output_segment* seg1,
2400                          const Output_segment* seg2)
2401 {
2402   elfcpp::Elf_Word type1 = seg1->type();
2403   elfcpp::Elf_Word type2 = seg2->type();
2404
2405   // The single PT_PHDR segment is required to precede any loadable
2406   // segment.  We simply make it always first.
2407   if (type1 == elfcpp::PT_PHDR)
2408     {
2409       gold_assert(type2 != elfcpp::PT_PHDR);
2410       return true;
2411     }
2412   if (type2 == elfcpp::PT_PHDR)
2413     return false;
2414
2415   // The single PT_INTERP segment is required to precede any loadable
2416   // segment.  We simply make it always second.
2417   if (type1 == elfcpp::PT_INTERP)
2418     {
2419       gold_assert(type2 != elfcpp::PT_INTERP);
2420       return true;
2421     }
2422   if (type2 == elfcpp::PT_INTERP)
2423     return false;
2424
2425   // We then put PT_LOAD segments before any other segments.
2426   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2427     return true;
2428   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2429     return false;
2430
2431   // We put the PT_TLS segment last except for the PT_GNU_RELRO
2432   // segment, because that is where the dynamic linker expects to find
2433   // it (this is just for efficiency; other positions would also work
2434   // correctly).
2435   if (type1 == elfcpp::PT_TLS
2436       && type2 != elfcpp::PT_TLS
2437       && type2 != elfcpp::PT_GNU_RELRO)
2438     return false;
2439   if (type2 == elfcpp::PT_TLS
2440       && type1 != elfcpp::PT_TLS
2441       && type1 != elfcpp::PT_GNU_RELRO)
2442     return true;
2443
2444   // We put the PT_GNU_RELRO segment last, because that is where the
2445   // dynamic linker expects to find it (as with PT_TLS, this is just
2446   // for efficiency).
2447   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2448     return false;
2449   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2450     return true;
2451
2452   const elfcpp::Elf_Word flags1 = seg1->flags();
2453   const elfcpp::Elf_Word flags2 = seg2->flags();
2454
2455   // The order of non-PT_LOAD segments is unimportant.  We simply sort
2456   // by the numeric segment type and flags values.  There should not
2457   // be more than one segment with the same type and flags.
2458   if (type1 != elfcpp::PT_LOAD)
2459     {
2460       if (type1 != type2)
2461         return type1 < type2;
2462       gold_assert(flags1 != flags2);
2463       return flags1 < flags2;
2464     }
2465
2466   // If the addresses are set already, sort by load address.
2467   if (seg1->are_addresses_set())
2468     {
2469       if (!seg2->are_addresses_set())
2470         return true;
2471
2472       unsigned int section_count1 = seg1->output_section_count();
2473       unsigned int section_count2 = seg2->output_section_count();
2474       if (section_count1 == 0 && section_count2 > 0)
2475         return true;
2476       if (section_count1 > 0 && section_count2 == 0)
2477         return false;
2478
2479       uint64_t paddr1 = (seg1->are_addresses_set()
2480                          ? seg1->paddr()
2481                          : seg1->first_section_load_address());
2482       uint64_t paddr2 = (seg2->are_addresses_set()
2483                          ? seg2->paddr()
2484                          : seg2->first_section_load_address());
2485
2486       if (paddr1 != paddr2)
2487         return paddr1 < paddr2;
2488     }
2489   else if (seg2->are_addresses_set())
2490     return false;
2491
2492   // A segment which holds large data comes after a segment which does
2493   // not hold large data.
2494   if (seg1->is_large_data_segment())
2495     {
2496       if (!seg2->is_large_data_segment())
2497         return false;
2498     }
2499   else if (seg2->is_large_data_segment())
2500     return true;
2501
2502   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
2503   // segments come before writable segments.  Then writable segments
2504   // with data come before writable segments without data.  Then
2505   // executable segments come before non-executable segments.  Then
2506   // the unlikely case of a non-readable segment comes before the
2507   // normal case of a readable segment.  If there are multiple
2508   // segments with the same type and flags, we require that the
2509   // address be set, and we sort by virtual address and then physical
2510   // address.
2511   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2512     return (flags1 & elfcpp::PF_W) == 0;
2513   if ((flags1 & elfcpp::PF_W) != 0
2514       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2515     return seg1->has_any_data_sections();
2516   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2517     return (flags1 & elfcpp::PF_X) != 0;
2518   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2519     return (flags1 & elfcpp::PF_R) == 0;
2520
2521   // We shouldn't get here--we shouldn't create segments which we
2522   // can't distinguish.
2523   gold_unreachable();
2524 }
2525
2526 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2527
2528 static off_t
2529 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2530 {
2531   uint64_t unsigned_off = off;
2532   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2533                           | (addr & (abi_pagesize - 1)));
2534   if (aligned_off < unsigned_off)
2535     aligned_off += abi_pagesize;
2536   return aligned_off;
2537 }
2538
2539 // Set the file offsets of all the segments, and all the sections they
2540 // contain.  They have all been created.  LOAD_SEG must be be laid out
2541 // first.  Return the offset of the data to follow.
2542
2543 off_t
2544 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
2545                             unsigned int* pshndx)
2546 {
2547   // Sort them into the final order.
2548   std::sort(this->segment_list_.begin(), this->segment_list_.end(),
2549             Layout::Compare_segments());
2550
2551   // Find the PT_LOAD segments, and set their addresses and offsets
2552   // and their section's addresses and offsets.
2553   uint64_t addr;
2554   if (parameters->options().user_set_Ttext())
2555     addr = parameters->options().Ttext();
2556   else if (parameters->options().output_is_position_independent())
2557     addr = 0;
2558   else
2559     addr = target->default_text_segment_address();
2560   off_t off = 0;
2561
2562   // If LOAD_SEG is NULL, then the file header and segment headers
2563   // will not be loadable.  But they still need to be at offset 0 in
2564   // the file.  Set their offsets now.
2565   if (load_seg == NULL)
2566     {
2567       for (Data_list::iterator p = this->special_output_list_.begin();
2568            p != this->special_output_list_.end();
2569            ++p)
2570         {
2571           off = align_address(off, (*p)->addralign());
2572           (*p)->set_address_and_file_offset(0, off);
2573           off += (*p)->data_size();
2574         }
2575     }
2576
2577   unsigned int increase_relro = this->increase_relro_;
2578   if (this->script_options_->saw_sections_clause())
2579     increase_relro = 0;
2580
2581   const bool check_sections = parameters->options().check_sections();
2582   Output_segment* last_load_segment = NULL;
2583
2584   for (Segment_list::iterator p = this->segment_list_.begin();
2585        p != this->segment_list_.end();
2586        ++p)
2587     {
2588       if ((*p)->type() == elfcpp::PT_LOAD)
2589         {
2590           if (load_seg != NULL && load_seg != *p)
2591             gold_unreachable();
2592           load_seg = NULL;
2593
2594           bool are_addresses_set = (*p)->are_addresses_set();
2595           if (are_addresses_set)
2596             {
2597               // When it comes to setting file offsets, we care about
2598               // the physical address.
2599               addr = (*p)->paddr();
2600             }
2601           else if (parameters->options().user_set_Tdata()
2602                    && ((*p)->flags() & elfcpp::PF_W) != 0
2603                    && (!parameters->options().user_set_Tbss()
2604                        || (*p)->has_any_data_sections()))
2605             {
2606               addr = parameters->options().Tdata();
2607               are_addresses_set = true;
2608             }
2609           else if (parameters->options().user_set_Tbss()
2610                    && ((*p)->flags() & elfcpp::PF_W) != 0
2611                    && !(*p)->has_any_data_sections())
2612             {
2613               addr = parameters->options().Tbss();
2614               are_addresses_set = true;
2615             }
2616
2617           uint64_t orig_addr = addr;
2618           uint64_t orig_off = off;
2619
2620           uint64_t aligned_addr = 0;
2621           uint64_t abi_pagesize = target->abi_pagesize();
2622           uint64_t common_pagesize = target->common_pagesize();
2623
2624           if (!parameters->options().nmagic()
2625               && !parameters->options().omagic())
2626             (*p)->set_minimum_p_align(common_pagesize);
2627
2628           if (!are_addresses_set)
2629             {
2630               // Skip the address forward one page, maintaining the same
2631               // position within the page.  This lets us store both segments
2632               // overlapping on a single page in the file, but the loader will
2633               // put them on different pages in memory. We will revisit this
2634               // decision once we know the size of the segment.
2635
2636               addr = align_address(addr, (*p)->maximum_alignment());
2637               aligned_addr = addr;
2638
2639               if ((addr & (abi_pagesize - 1)) != 0)
2640                 addr = addr + abi_pagesize;
2641
2642               off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2643             }
2644
2645           if (!parameters->options().nmagic()
2646               && !parameters->options().omagic())
2647             off = align_file_offset(off, addr, abi_pagesize);
2648           else if (load_seg == NULL)
2649             {
2650               // This is -N or -n with a section script which prevents
2651               // us from using a load segment.  We need to ensure that
2652               // the file offset is aligned to the alignment of the
2653               // segment.  This is because the linker script
2654               // implicitly assumed a zero offset.  If we don't align
2655               // here, then the alignment of the sections in the
2656               // linker script may not match the alignment of the
2657               // sections in the set_section_addresses call below,
2658               // causing an error about dot moving backward.
2659               off = align_address(off, (*p)->maximum_alignment());
2660             }
2661
2662           unsigned int shndx_hold = *pshndx;
2663           bool has_relro = false;
2664           uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
2665                                                           increase_relro,
2666                                                           &has_relro,
2667                                                           &off, pshndx);
2668
2669           // Now that we know the size of this segment, we may be able
2670           // to save a page in memory, at the cost of wasting some
2671           // file space, by instead aligning to the start of a new
2672           // page.  Here we use the real machine page size rather than
2673           // the ABI mandated page size.  If the segment has been
2674           // aligned so that the relro data ends at a page boundary,
2675           // we do not try to realign it.
2676
2677           if (!are_addresses_set && !has_relro && aligned_addr != addr)
2678             {
2679               uint64_t first_off = (common_pagesize
2680                                     - (aligned_addr
2681                                        & (common_pagesize - 1)));
2682               uint64_t last_off = new_addr & (common_pagesize - 1);
2683               if (first_off > 0
2684                   && last_off > 0
2685                   && ((aligned_addr & ~ (common_pagesize - 1))
2686                       != (new_addr & ~ (common_pagesize - 1)))
2687                   && first_off + last_off <= common_pagesize)
2688                 {
2689                   *pshndx = shndx_hold;
2690                   addr = align_address(aligned_addr, common_pagesize);
2691                   addr = align_address(addr, (*p)->maximum_alignment());
2692                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2693                   off = align_file_offset(off, addr, abi_pagesize);
2694                   new_addr = (*p)->set_section_addresses(this, true, addr,
2695                                                          increase_relro,
2696                                                          &has_relro,
2697                                                          &off, pshndx);
2698                 }
2699             }
2700
2701           addr = new_addr;
2702
2703           // Implement --check-sections.  We know that the segments
2704           // are sorted by LMA.
2705           if (check_sections && last_load_segment != NULL)
2706             {
2707               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
2708               if (last_load_segment->paddr() + last_load_segment->memsz()
2709                   > (*p)->paddr())
2710                 {
2711                   unsigned long long lb1 = last_load_segment->paddr();
2712                   unsigned long long le1 = lb1 + last_load_segment->memsz();
2713                   unsigned long long lb2 = (*p)->paddr();
2714                   unsigned long long le2 = lb2 + (*p)->memsz();
2715                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
2716                                "[0x%llx -> 0x%llx]"),
2717                              lb1, le1, lb2, le2);
2718                 }
2719             }
2720           last_load_segment = *p;
2721         }
2722     }
2723
2724   // Handle the non-PT_LOAD segments, setting their offsets from their
2725   // section's offsets.
2726   for (Segment_list::iterator p = this->segment_list_.begin();
2727        p != this->segment_list_.end();
2728        ++p)
2729     {
2730       if ((*p)->type() != elfcpp::PT_LOAD)
2731         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
2732                          ? increase_relro
2733                          : 0);
2734     }
2735
2736   // Set the TLS offsets for each section in the PT_TLS segment.
2737   if (this->tls_segment_ != NULL)
2738     this->tls_segment_->set_tls_offsets();
2739
2740   return off;
2741 }
2742
2743 // Set the offsets of all the allocated sections when doing a
2744 // relocatable link.  This does the same jobs as set_segment_offsets,
2745 // only for a relocatable link.
2746
2747 off_t
2748 Layout::set_relocatable_section_offsets(Output_data* file_header,
2749                                         unsigned int* pshndx)
2750 {
2751   off_t off = 0;
2752
2753   file_header->set_address_and_file_offset(0, 0);
2754   off += file_header->data_size();
2755
2756   for (Section_list::iterator p = this->section_list_.begin();
2757        p != this->section_list_.end();
2758        ++p)
2759     {
2760       // We skip unallocated sections here, except that group sections
2761       // have to come first.
2762       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
2763           && (*p)->type() != elfcpp::SHT_GROUP)
2764         continue;
2765
2766       off = align_address(off, (*p)->addralign());
2767
2768       // The linker script might have set the address.
2769       if (!(*p)->is_address_valid())
2770         (*p)->set_address(0);
2771       (*p)->set_file_offset(off);
2772       (*p)->finalize_data_size();
2773       off += (*p)->data_size();
2774
2775       (*p)->set_out_shndx(*pshndx);
2776       ++*pshndx;
2777     }
2778
2779   return off;
2780 }
2781
2782 // Set the file offset of all the sections not associated with a
2783 // segment.
2784
2785 off_t
2786 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
2787 {
2788   for (Section_list::iterator p = this->unattached_section_list_.begin();
2789        p != this->unattached_section_list_.end();
2790        ++p)
2791     {
2792       // The symtab section is handled in create_symtab_sections.
2793       if (*p == this->symtab_section_)
2794         continue;
2795
2796       // If we've already set the data size, don't set it again.
2797       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
2798         continue;
2799
2800       if (pass == BEFORE_INPUT_SECTIONS_PASS
2801           && (*p)->requires_postprocessing())
2802         {
2803           (*p)->create_postprocessing_buffer();
2804           this->any_postprocessing_sections_ = true;
2805         }
2806
2807       if (pass == BEFORE_INPUT_SECTIONS_PASS
2808           && (*p)->after_input_sections())
2809         continue;
2810       else if (pass == POSTPROCESSING_SECTIONS_PASS
2811                && (!(*p)->after_input_sections()
2812                    || (*p)->type() == elfcpp::SHT_STRTAB))
2813         continue;
2814       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
2815                && (!(*p)->after_input_sections()
2816                    || (*p)->type() != elfcpp::SHT_STRTAB))
2817         continue;
2818
2819       off = align_address(off, (*p)->addralign());
2820       (*p)->set_file_offset(off);
2821       (*p)->finalize_data_size();
2822       off += (*p)->data_size();
2823
2824       // At this point the name must be set.
2825       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
2826         this->namepool_.add((*p)->name(), false, NULL);
2827     }
2828   return off;
2829 }
2830
2831 // Set the section indexes of all the sections not associated with a
2832 // segment.
2833
2834 unsigned int
2835 Layout::set_section_indexes(unsigned int shndx)
2836 {
2837   for (Section_list::iterator p = this->unattached_section_list_.begin();
2838        p != this->unattached_section_list_.end();
2839        ++p)
2840     {
2841       if (!(*p)->has_out_shndx())
2842         {
2843           (*p)->set_out_shndx(shndx);
2844           ++shndx;
2845         }
2846     }
2847   return shndx;
2848 }
2849
2850 // Set the section addresses according to the linker script.  This is
2851 // only called when we see a SECTIONS clause.  This returns the
2852 // program segment which should hold the file header and segment
2853 // headers, if any.  It will return NULL if they should not be in a
2854 // segment.
2855
2856 Output_segment*
2857 Layout::set_section_addresses_from_script(Symbol_table* symtab)
2858 {
2859   Script_sections* ss = this->script_options_->script_sections();
2860   gold_assert(ss->saw_sections_clause());
2861   return this->script_options_->set_section_addresses(symtab, this);
2862 }
2863
2864 // Place the orphan sections in the linker script.
2865
2866 void
2867 Layout::place_orphan_sections_in_script()
2868 {
2869   Script_sections* ss = this->script_options_->script_sections();
2870   gold_assert(ss->saw_sections_clause());
2871
2872   // Place each orphaned output section in the script.
2873   for (Section_list::iterator p = this->section_list_.begin();
2874        p != this->section_list_.end();
2875        ++p)
2876     {
2877       if (!(*p)->found_in_sections_clause())
2878         ss->place_orphan(*p);
2879     }
2880 }
2881
2882 // Count the local symbols in the regular symbol table and the dynamic
2883 // symbol table, and build the respective string pools.
2884
2885 void
2886 Layout::count_local_symbols(const Task* task,
2887                             const Input_objects* input_objects)
2888 {
2889   // First, figure out an upper bound on the number of symbols we'll
2890   // be inserting into each pool.  This helps us create the pools with
2891   // the right size, to avoid unnecessary hashtable resizing.
2892   unsigned int symbol_count = 0;
2893   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2894        p != input_objects->relobj_end();
2895        ++p)
2896     symbol_count += (*p)->local_symbol_count();
2897
2898   // Go from "upper bound" to "estimate."  We overcount for two
2899   // reasons: we double-count symbols that occur in more than one
2900   // object file, and we count symbols that are dropped from the
2901   // output.  Add it all together and assume we overcount by 100%.
2902   symbol_count /= 2;
2903
2904   // We assume all symbols will go into both the sympool and dynpool.
2905   this->sympool_.reserve(symbol_count);
2906   this->dynpool_.reserve(symbol_count);
2907
2908   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2909        p != input_objects->relobj_end();
2910        ++p)
2911     {
2912       Task_lock_obj<Object> tlo(task, *p);
2913       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
2914     }
2915 }
2916
2917 // Create the symbol table sections.  Here we also set the final
2918 // values of the symbols.  At this point all the loadable sections are
2919 // fully laid out.  SHNUM is the number of sections so far.
2920
2921 void
2922 Layout::create_symtab_sections(const Input_objects* input_objects,
2923                                Symbol_table* symtab,
2924                                unsigned int shnum,
2925                                off_t* poff)
2926 {
2927   int symsize;
2928   unsigned int align;
2929   if (parameters->target().get_size() == 32)
2930     {
2931       symsize = elfcpp::Elf_sizes<32>::sym_size;
2932       align = 4;
2933     }
2934   else if (parameters->target().get_size() == 64)
2935     {
2936       symsize = elfcpp::Elf_sizes<64>::sym_size;
2937       align = 8;
2938     }
2939   else
2940     gold_unreachable();
2941
2942   off_t off = *poff;
2943   off = align_address(off, align);
2944   off_t startoff = off;
2945
2946   // Save space for the dummy symbol at the start of the section.  We
2947   // never bother to write this out--it will just be left as zero.
2948   off += symsize;
2949   unsigned int local_symbol_index = 1;
2950
2951   // Add STT_SECTION symbols for each Output section which needs one.
2952   for (Section_list::iterator p = this->section_list_.begin();
2953        p != this->section_list_.end();
2954        ++p)
2955     {
2956       if (!(*p)->needs_symtab_index())
2957         (*p)->set_symtab_index(-1U);
2958       else
2959         {
2960           (*p)->set_symtab_index(local_symbol_index);
2961           ++local_symbol_index;
2962           off += symsize;
2963         }
2964     }
2965
2966   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2967        p != input_objects->relobj_end();
2968        ++p)
2969     {
2970       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
2971                                                         off, symtab);
2972       off += (index - local_symbol_index) * symsize;
2973       local_symbol_index = index;
2974     }
2975
2976   unsigned int local_symcount = local_symbol_index;
2977   gold_assert(static_cast<off_t>(local_symcount * symsize) == off - startoff);
2978
2979   off_t dynoff;
2980   size_t dyn_global_index;
2981   size_t dyncount;
2982   if (this->dynsym_section_ == NULL)
2983     {
2984       dynoff = 0;
2985       dyn_global_index = 0;
2986       dyncount = 0;
2987     }
2988   else
2989     {
2990       dyn_global_index = this->dynsym_section_->info();
2991       off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
2992       dynoff = this->dynsym_section_->offset() + locsize;
2993       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
2994       gold_assert(static_cast<off_t>(dyncount * symsize)
2995                   == this->dynsym_section_->data_size() - locsize);
2996     }
2997
2998   off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
2999                          &this->sympool_, &local_symcount);
3000
3001   if (!parameters->options().strip_all())
3002     {
3003       this->sympool_.set_string_offsets();
3004
3005       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
3006       Output_section* osymtab = this->make_output_section(symtab_name,
3007                                                           elfcpp::SHT_SYMTAB,
3008                                                           0, ORDER_INVALID,
3009                                                           false);
3010       this->symtab_section_ = osymtab;
3011
3012       Output_section_data* pos = new Output_data_fixed_space(off - startoff,
3013                                                              align,
3014                                                              "** symtab");
3015       osymtab->add_output_section_data(pos);
3016
3017       // We generate a .symtab_shndx section if we have more than
3018       // SHN_LORESERVE sections.  Technically it is possible that we
3019       // don't need one, because it is possible that there are no
3020       // symbols in any of sections with indexes larger than
3021       // SHN_LORESERVE.  That is probably unusual, though, and it is
3022       // easier to always create one than to compute section indexes
3023       // twice (once here, once when writing out the symbols).
3024       if (shnum >= elfcpp::SHN_LORESERVE)
3025         {
3026           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3027                                                                false, NULL);
3028           Output_section* osymtab_xindex =
3029             this->make_output_section(symtab_xindex_name,
3030                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
3031                                       ORDER_INVALID, false);
3032
3033           size_t symcount = (off - startoff) / symsize;
3034           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3035
3036           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3037
3038           osymtab_xindex->set_link_section(osymtab);
3039           osymtab_xindex->set_addralign(4);
3040           osymtab_xindex->set_entsize(4);
3041
3042           osymtab_xindex->set_after_input_sections();
3043
3044           // This tells the driver code to wait until the symbol table
3045           // has written out before writing out the postprocessing
3046           // sections, including the .symtab_shndx section.
3047           this->any_postprocessing_sections_ = true;
3048         }
3049
3050       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3051       Output_section* ostrtab = this->make_output_section(strtab_name,
3052                                                           elfcpp::SHT_STRTAB,
3053                                                           0, ORDER_INVALID,
3054                                                           false);
3055
3056       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3057       ostrtab->add_output_section_data(pstr);
3058
3059       osymtab->set_file_offset(startoff);
3060       osymtab->finalize_data_size();
3061       osymtab->set_link_section(ostrtab);
3062       osymtab->set_info(local_symcount);
3063       osymtab->set_entsize(symsize);
3064
3065       *poff = off;
3066     }
3067 }
3068
3069 // Create the .shstrtab section, which holds the names of the
3070 // sections.  At the time this is called, we have created all the
3071 // output sections except .shstrtab itself.
3072
3073 Output_section*
3074 Layout::create_shstrtab()
3075 {
3076   // FIXME: We don't need to create a .shstrtab section if we are
3077   // stripping everything.
3078
3079   const char* name = this->namepool_.add(".shstrtab", false, NULL);
3080
3081   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3082                                                  ORDER_INVALID, false);
3083
3084   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3085     {
3086       // We can't write out this section until we've set all the
3087       // section names, and we don't set the names of compressed
3088       // output sections until relocations are complete.  FIXME: With
3089       // the current names we use, this is unnecessary.
3090       os->set_after_input_sections();
3091     }
3092
3093   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3094   os->add_output_section_data(posd);
3095
3096   return os;
3097 }
3098
3099 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
3100 // offset.
3101
3102 void
3103 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3104 {
3105   Output_section_headers* oshdrs;
3106   oshdrs = new Output_section_headers(this,
3107                                       &this->segment_list_,
3108                                       &this->section_list_,
3109                                       &this->unattached_section_list_,
3110                                       &this->namepool_,
3111                                       shstrtab_section);
3112   off_t off = align_address(*poff, oshdrs->addralign());
3113   oshdrs->set_address_and_file_offset(0, off);
3114   off += oshdrs->data_size();
3115   *poff = off;
3116   this->section_headers_ = oshdrs;
3117 }
3118
3119 // Count the allocated sections.
3120
3121 size_t
3122 Layout::allocated_output_section_count() const
3123 {
3124   size_t section_count = 0;
3125   for (Segment_list::const_iterator p = this->segment_list_.begin();
3126        p != this->segment_list_.end();
3127        ++p)
3128     section_count += (*p)->output_section_count();
3129   return section_count;
3130 }
3131
3132 // Create the dynamic symbol table.
3133
3134 void
3135 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3136                               Symbol_table* symtab,
3137                               Output_section** pdynstr,
3138                               unsigned int* plocal_dynamic_count,
3139                               std::vector<Symbol*>* pdynamic_symbols,
3140                               Versions* pversions)
3141 {
3142   // Count all the symbols in the dynamic symbol table, and set the
3143   // dynamic symbol indexes.
3144
3145   // Skip symbol 0, which is always all zeroes.
3146   unsigned int index = 1;
3147
3148   // Add STT_SECTION symbols for each Output section which needs one.
3149   for (Section_list::iterator p = this->section_list_.begin();
3150        p != this->section_list_.end();
3151        ++p)
3152     {
3153       if (!(*p)->needs_dynsym_index())
3154         (*p)->set_dynsym_index(-1U);
3155       else
3156         {
3157           (*p)->set_dynsym_index(index);
3158           ++index;
3159         }
3160     }
3161
3162   // Count the local symbols that need to go in the dynamic symbol table,
3163   // and set the dynamic symbol indexes.
3164   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3165        p != input_objects->relobj_end();
3166        ++p)
3167     {
3168       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3169       index = new_index;
3170     }
3171
3172   unsigned int local_symcount = index;
3173   *plocal_dynamic_count = local_symcount;
3174
3175   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3176                                      &this->dynpool_, pversions);
3177
3178   int symsize;
3179   unsigned int align;
3180   const int size = parameters->target().get_size();
3181   if (size == 32)
3182     {
3183       symsize = elfcpp::Elf_sizes<32>::sym_size;
3184       align = 4;
3185     }
3186   else if (size == 64)
3187     {
3188       symsize = elfcpp::Elf_sizes<64>::sym_size;
3189       align = 8;
3190     }
3191   else
3192     gold_unreachable();
3193
3194   // Create the dynamic symbol table section.
3195
3196   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3197                                                        elfcpp::SHT_DYNSYM,
3198                                                        elfcpp::SHF_ALLOC,
3199                                                        false,
3200                                                        ORDER_DYNAMIC_LINKER,
3201                                                        false);
3202
3203   Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3204                                                            align,
3205                                                            "** dynsym");
3206   dynsym->add_output_section_data(odata);
3207
3208   dynsym->set_info(local_symcount);
3209   dynsym->set_entsize(symsize);
3210   dynsym->set_addralign(align);
3211
3212   this->dynsym_section_ = dynsym;
3213
3214   Output_data_dynamic* const odyn = this->dynamic_data_;
3215   odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3216   odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3217
3218   // If there are more than SHN_LORESERVE allocated sections, we
3219   // create a .dynsym_shndx section.  It is possible that we don't
3220   // need one, because it is possible that there are no dynamic
3221   // symbols in any of the sections with indexes larger than
3222   // SHN_LORESERVE.  This is probably unusual, though, and at this
3223   // time we don't know the actual section indexes so it is
3224   // inconvenient to check.
3225   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3226     {
3227       Output_section* dynsym_xindex =
3228         this->choose_output_section(NULL, ".dynsym_shndx",
3229                                     elfcpp::SHT_SYMTAB_SHNDX,
3230                                     elfcpp::SHF_ALLOC,
3231                                     false, ORDER_DYNAMIC_LINKER, false);
3232
3233       this->dynsym_xindex_ = new Output_symtab_xindex(index);
3234
3235       dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3236
3237       dynsym_xindex->set_link_section(dynsym);
3238       dynsym_xindex->set_addralign(4);
3239       dynsym_xindex->set_entsize(4);
3240
3241       dynsym_xindex->set_after_input_sections();
3242
3243       // This tells the driver code to wait until the symbol table has
3244       // written out before writing out the postprocessing sections,
3245       // including the .dynsym_shndx section.
3246       this->any_postprocessing_sections_ = true;
3247     }
3248
3249   // Create the dynamic string table section.
3250
3251   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3252                                                        elfcpp::SHT_STRTAB,
3253                                                        elfcpp::SHF_ALLOC,
3254                                                        false,
3255                                                        ORDER_DYNAMIC_LINKER,
3256                                                        false);
3257
3258   Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3259   dynstr->add_output_section_data(strdata);
3260
3261   dynsym->set_link_section(dynstr);
3262   this->dynamic_section_->set_link_section(dynstr);
3263
3264   odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3265   odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3266
3267   *pdynstr = dynstr;
3268
3269   // Create the hash tables.
3270
3271   if (strcmp(parameters->options().hash_style(), "sysv") == 0
3272       || strcmp(parameters->options().hash_style(), "both") == 0)
3273     {
3274       unsigned char* phash;
3275       unsigned int hashlen;
3276       Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3277                                     &phash, &hashlen);
3278
3279       Output_section* hashsec =
3280         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3281                                     elfcpp::SHF_ALLOC, false,
3282                                     ORDER_DYNAMIC_LINKER, false);
3283
3284       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3285                                                                    hashlen,
3286                                                                    align,
3287                                                                    "** hash");
3288       hashsec->add_output_section_data(hashdata);
3289
3290       hashsec->set_link_section(dynsym);
3291       hashsec->set_entsize(4);
3292
3293       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3294     }
3295
3296   if (strcmp(parameters->options().hash_style(), "gnu") == 0
3297       || strcmp(parameters->options().hash_style(), "both") == 0)
3298     {
3299       unsigned char* phash;
3300       unsigned int hashlen;
3301       Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3302                                     &phash, &hashlen);
3303
3304       Output_section* hashsec =
3305         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3306                                     elfcpp::SHF_ALLOC, false,
3307                                     ORDER_DYNAMIC_LINKER, false);
3308
3309       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3310                                                                    hashlen,
3311                                                                    align,
3312                                                                    "** hash");
3313       hashsec->add_output_section_data(hashdata);
3314
3315       hashsec->set_link_section(dynsym);
3316
3317       // For a 64-bit target, the entries in .gnu.hash do not have a
3318       // uniform size, so we only set the entry size for a 32-bit
3319       // target.
3320       if (parameters->target().get_size() == 32)
3321         hashsec->set_entsize(4);
3322
3323       odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3324     }
3325 }
3326
3327 // Assign offsets to each local portion of the dynamic symbol table.
3328
3329 void
3330 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3331 {
3332   Output_section* dynsym = this->dynsym_section_;
3333   gold_assert(dynsym != NULL);
3334
3335   off_t off = dynsym->offset();
3336
3337   // Skip the dummy symbol at the start of the section.
3338   off += dynsym->entsize();
3339
3340   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3341        p != input_objects->relobj_end();
3342        ++p)
3343     {
3344       unsigned int count = (*p)->set_local_dynsym_offset(off);
3345       off += count * dynsym->entsize();
3346     }
3347 }
3348
3349 // Create the version sections.
3350
3351 void
3352 Layout::create_version_sections(const Versions* versions,
3353                                 const Symbol_table* symtab,
3354                                 unsigned int local_symcount,
3355                                 const std::vector<Symbol*>& dynamic_symbols,
3356                                 const Output_section* dynstr)
3357 {
3358   if (!versions->any_defs() && !versions->any_needs())
3359     return;
3360
3361   switch (parameters->size_and_endianness())
3362     {
3363 #ifdef HAVE_TARGET_32_LITTLE
3364     case Parameters::TARGET_32_LITTLE:
3365       this->sized_create_version_sections<32, false>(versions, symtab,
3366                                                      local_symcount,
3367                                                      dynamic_symbols, dynstr);
3368       break;
3369 #endif
3370 #ifdef HAVE_TARGET_32_BIG
3371     case Parameters::TARGET_32_BIG:
3372       this->sized_create_version_sections<32, true>(versions, symtab,
3373                                                     local_symcount,
3374                                                     dynamic_symbols, dynstr);
3375       break;
3376 #endif
3377 #ifdef HAVE_TARGET_64_LITTLE
3378     case Parameters::TARGET_64_LITTLE:
3379       this->sized_create_version_sections<64, false>(versions, symtab,
3380                                                      local_symcount,
3381                                                      dynamic_symbols, dynstr);
3382       break;
3383 #endif
3384 #ifdef HAVE_TARGET_64_BIG
3385     case Parameters::TARGET_64_BIG:
3386       this->sized_create_version_sections<64, true>(versions, symtab,
3387                                                     local_symcount,
3388                                                     dynamic_symbols, dynstr);
3389       break;
3390 #endif
3391     default:
3392       gold_unreachable();
3393     }
3394 }
3395
3396 // Create the version sections, sized version.
3397
3398 template<int size, bool big_endian>
3399 void
3400 Layout::sized_create_version_sections(
3401     const Versions* versions,
3402     const Symbol_table* symtab,
3403     unsigned int local_symcount,
3404     const std::vector<Symbol*>& dynamic_symbols,
3405     const Output_section* dynstr)
3406 {
3407   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3408                                                      elfcpp::SHT_GNU_versym,
3409                                                      elfcpp::SHF_ALLOC,
3410                                                      false,
3411                                                      ORDER_DYNAMIC_LINKER,
3412                                                      false);
3413
3414   unsigned char* vbuf;
3415   unsigned int vsize;
3416   versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
3417                                                       local_symcount,
3418                                                       dynamic_symbols,
3419                                                       &vbuf, &vsize);
3420
3421   Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
3422                                                             "** versions");
3423
3424   vsec->add_output_section_data(vdata);
3425   vsec->set_entsize(2);
3426   vsec->set_link_section(this->dynsym_section_);
3427
3428   Output_data_dynamic* const odyn = this->dynamic_data_;
3429   odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
3430
3431   if (versions->any_defs())
3432     {
3433       Output_section* vdsec;
3434       vdsec= this->choose_output_section(NULL, ".gnu.version_d",
3435                                          elfcpp::SHT_GNU_verdef,
3436                                          elfcpp::SHF_ALLOC,
3437                                          false, ORDER_DYNAMIC_LINKER, false);
3438
3439       unsigned char* vdbuf;
3440       unsigned int vdsize;
3441       unsigned int vdentries;
3442       versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
3443                                                        &vdsize, &vdentries);
3444
3445       Output_section_data* vddata =
3446         new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
3447
3448       vdsec->add_output_section_data(vddata);
3449       vdsec->set_link_section(dynstr);
3450       vdsec->set_info(vdentries);
3451
3452       odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
3453       odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
3454     }
3455
3456   if (versions->any_needs())
3457     {
3458       Output_section* vnsec;
3459       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
3460                                           elfcpp::SHT_GNU_verneed,
3461                                           elfcpp::SHF_ALLOC,
3462                                           false, ORDER_DYNAMIC_LINKER, false);
3463
3464       unsigned char* vnbuf;
3465       unsigned int vnsize;
3466       unsigned int vnentries;
3467       versions->need_section_contents<size, big_endian>(&this->dynpool_,
3468                                                         &vnbuf, &vnsize,
3469                                                         &vnentries);
3470
3471       Output_section_data* vndata =
3472         new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
3473
3474       vnsec->add_output_section_data(vndata);
3475       vnsec->set_link_section(dynstr);
3476       vnsec->set_info(vnentries);
3477
3478       odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
3479       odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
3480     }
3481 }
3482
3483 // Create the .interp section and PT_INTERP segment.
3484
3485 void
3486 Layout::create_interp(const Target* target)
3487 {
3488   const char* interp = parameters->options().dynamic_linker();
3489   if (interp == NULL)
3490     {
3491       interp = target->dynamic_linker();
3492       gold_assert(interp != NULL);
3493     }
3494
3495   size_t len = strlen(interp) + 1;
3496
3497   Output_section_data* odata = new Output_data_const(interp, len, 1);
3498
3499   Output_section* osec = this->choose_output_section(NULL, ".interp",
3500                                                      elfcpp::SHT_PROGBITS,
3501                                                      elfcpp::SHF_ALLOC,
3502                                                      false, ORDER_INTERP,
3503                                                      false);
3504   osec->add_output_section_data(odata);
3505
3506   if (!this->script_options_->saw_phdrs_clause())
3507     {
3508       Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
3509                                                        elfcpp::PF_R);
3510       oseg->add_output_section_to_nonload(osec, elfcpp::PF_R);
3511     }
3512 }
3513
3514 // Add dynamic tags for the PLT and the dynamic relocs.  This is
3515 // called by the target-specific code.  This does nothing if not doing
3516 // a dynamic link.
3517
3518 // USE_REL is true for REL relocs rather than RELA relocs.
3519
3520 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3521
3522 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3523 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
3524 // some targets have multiple reloc sections in PLT_REL.
3525
3526 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3527 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3528
3529 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3530 // executable.
3531
3532 void
3533 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
3534                                 const Output_data* plt_rel,
3535                                 const Output_data_reloc_generic* dyn_rel,
3536                                 bool add_debug, bool dynrel_includes_plt)
3537 {
3538   Output_data_dynamic* odyn = this->dynamic_data_;
3539   if (odyn == NULL)
3540     return;
3541
3542   if (plt_got != NULL && plt_got->output_section() != NULL)
3543     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
3544
3545   if (plt_rel != NULL && plt_rel->output_section() != NULL)
3546     {
3547       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
3548       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
3549       odyn->add_constant(elfcpp::DT_PLTREL,
3550                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
3551     }
3552
3553   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
3554     {
3555       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
3556                                 dyn_rel);
3557       if (plt_rel != NULL && dynrel_includes_plt)
3558         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3559                                dyn_rel, plt_rel);
3560       else
3561         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3562                                dyn_rel);
3563       const int size = parameters->target().get_size();
3564       elfcpp::DT rel_tag;
3565       int rel_size;
3566       if (use_rel)
3567         {
3568           rel_tag = elfcpp::DT_RELENT;
3569           if (size == 32)
3570             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
3571           else if (size == 64)
3572             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
3573           else
3574             gold_unreachable();
3575         }
3576       else
3577         {
3578           rel_tag = elfcpp::DT_RELAENT;
3579           if (size == 32)
3580             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
3581           else if (size == 64)
3582             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
3583           else
3584             gold_unreachable();
3585         }
3586       odyn->add_constant(rel_tag, rel_size);
3587
3588       if (parameters->options().combreloc())
3589         {
3590           size_t c = dyn_rel->relative_reloc_count();
3591           if (c > 0)
3592             odyn->add_constant((use_rel
3593                                 ? elfcpp::DT_RELCOUNT
3594                                 : elfcpp::DT_RELACOUNT),
3595                                c);
3596         }
3597     }
3598
3599   if (add_debug && !parameters->options().shared())
3600     {
3601       // The value of the DT_DEBUG tag is filled in by the dynamic
3602       // linker at run time, and used by the debugger.
3603       odyn->add_constant(elfcpp::DT_DEBUG, 0);
3604     }
3605 }
3606
3607 // Finish the .dynamic section and PT_DYNAMIC segment.
3608
3609 void
3610 Layout::finish_dynamic_section(const Input_objects* input_objects,
3611                                const Symbol_table* symtab)
3612 {
3613   if (!this->script_options_->saw_phdrs_clause())
3614     {
3615       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
3616                                                        (elfcpp::PF_R
3617                                                         | elfcpp::PF_W));
3618       oseg->add_output_section_to_nonload(this->dynamic_section_,
3619                                           elfcpp::PF_R | elfcpp::PF_W);
3620     }
3621
3622   Output_data_dynamic* const odyn = this->dynamic_data_;
3623
3624   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
3625        p != input_objects->dynobj_end();
3626        ++p)
3627     {
3628       if (!(*p)->is_needed()
3629           && (*p)->input_file()->options().as_needed())
3630         {
3631           // This dynamic object was linked with --as-needed, but it
3632           // is not needed.
3633           continue;
3634         }
3635
3636       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
3637     }
3638
3639   if (parameters->options().shared())
3640     {
3641       const char* soname = parameters->options().soname();
3642       if (soname != NULL)
3643         odyn->add_string(elfcpp::DT_SONAME, soname);
3644     }
3645
3646   Symbol* sym = symtab->lookup(parameters->options().init());
3647   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3648     odyn->add_symbol(elfcpp::DT_INIT, sym);
3649
3650   sym = symtab->lookup(parameters->options().fini());
3651   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
3652     odyn->add_symbol(elfcpp::DT_FINI, sym);
3653
3654   // Look for .init_array, .preinit_array and .fini_array by checking
3655   // section types.
3656   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
3657       p != this->section_list_.end();
3658       ++p)
3659     switch((*p)->type())
3660       {
3661       case elfcpp::SHT_FINI_ARRAY:
3662         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
3663         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
3664         break;
3665       case elfcpp::SHT_INIT_ARRAY:
3666         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
3667         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
3668         break;
3669       case elfcpp::SHT_PREINIT_ARRAY:
3670         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
3671         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
3672         break;
3673       default:
3674         break;
3675       }
3676
3677   // Add a DT_RPATH entry if needed.
3678   const General_options::Dir_list& rpath(parameters->options().rpath());
3679   if (!rpath.empty())
3680     {
3681       std::string rpath_val;
3682       for (General_options::Dir_list::const_iterator p = rpath.begin();
3683            p != rpath.end();
3684            ++p)
3685         {
3686           if (rpath_val.empty())
3687             rpath_val = p->name();
3688           else
3689             {
3690               // Eliminate duplicates.
3691               General_options::Dir_list::const_iterator q;
3692               for (q = rpath.begin(); q != p; ++q)
3693                 if (q->name() == p->name())
3694                   break;
3695               if (q == p)
3696                 {
3697                   rpath_val += ':';
3698                   rpath_val += p->name();
3699                 }
3700             }
3701         }
3702
3703       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
3704       if (parameters->options().enable_new_dtags())
3705         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
3706     }
3707
3708   // Look for text segments that have dynamic relocations.
3709   bool have_textrel = false;
3710   if (!this->script_options_->saw_sections_clause())
3711     {
3712       for (Segment_list::const_iterator p = this->segment_list_.begin();
3713            p != this->segment_list_.end();
3714            ++p)
3715         {
3716           if (((*p)->flags() & elfcpp::PF_W) == 0
3717               && (*p)->has_dynamic_reloc())
3718             {
3719               have_textrel = true;
3720               break;
3721             }
3722         }
3723     }
3724   else
3725     {
3726       // We don't know the section -> segment mapping, so we are
3727       // conservative and just look for readonly sections with
3728       // relocations.  If those sections wind up in writable segments,
3729       // then we have created an unnecessary DT_TEXTREL entry.
3730       for (Section_list::const_iterator p = this->section_list_.begin();
3731            p != this->section_list_.end();
3732            ++p)
3733         {
3734           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
3735               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
3736               && ((*p)->has_dynamic_reloc()))
3737             {
3738               have_textrel = true;
3739               break;
3740             }
3741         }
3742     }
3743
3744   // Add a DT_FLAGS entry. We add it even if no flags are set so that
3745   // post-link tools can easily modify these flags if desired.
3746   unsigned int flags = 0;
3747   if (have_textrel)
3748     {
3749       // Add a DT_TEXTREL for compatibility with older loaders.
3750       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
3751       flags |= elfcpp::DF_TEXTREL;
3752
3753       if (parameters->options().text())
3754         gold_error(_("read-only segment has dynamic relocations"));
3755       else if (parameters->options().warn_shared_textrel()
3756                && parameters->options().shared())
3757         gold_warning(_("shared library text segment is not shareable"));
3758     }
3759   if (parameters->options().shared() && this->has_static_tls())
3760     flags |= elfcpp::DF_STATIC_TLS;
3761   if (parameters->options().origin())
3762     flags |= elfcpp::DF_ORIGIN;
3763   if (parameters->options().Bsymbolic())
3764     {
3765       flags |= elfcpp::DF_SYMBOLIC;
3766       // Add DT_SYMBOLIC for compatibility with older loaders.
3767       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
3768     }
3769   if (parameters->options().now())
3770     flags |= elfcpp::DF_BIND_NOW;
3771   odyn->add_constant(elfcpp::DT_FLAGS, flags);
3772
3773   flags = 0;
3774   if (parameters->options().initfirst())
3775     flags |= elfcpp::DF_1_INITFIRST;
3776   if (parameters->options().interpose())
3777     flags |= elfcpp::DF_1_INTERPOSE;
3778   if (parameters->options().loadfltr())
3779     flags |= elfcpp::DF_1_LOADFLTR;
3780   if (parameters->options().nodefaultlib())
3781     flags |= elfcpp::DF_1_NODEFLIB;
3782   if (parameters->options().nodelete())
3783     flags |= elfcpp::DF_1_NODELETE;
3784   if (parameters->options().nodlopen())
3785     flags |= elfcpp::DF_1_NOOPEN;
3786   if (parameters->options().nodump())
3787     flags |= elfcpp::DF_1_NODUMP;
3788   if (!parameters->options().shared())
3789     flags &= ~(elfcpp::DF_1_INITFIRST
3790                | elfcpp::DF_1_NODELETE
3791                | elfcpp::DF_1_NOOPEN);
3792   if (parameters->options().origin())
3793     flags |= elfcpp::DF_1_ORIGIN;
3794   if (parameters->options().now())
3795     flags |= elfcpp::DF_1_NOW;
3796   if (flags)
3797     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
3798 }
3799
3800 // Set the size of the _DYNAMIC symbol table to be the size of the
3801 // dynamic data.
3802
3803 void
3804 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
3805 {
3806   Output_data_dynamic* const odyn = this->dynamic_data_;
3807   odyn->finalize_data_size();
3808   off_t data_size = odyn->data_size();
3809   const int size = parameters->target().get_size();
3810   if (size == 32)
3811     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
3812   else if (size == 64)
3813     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
3814   else
3815     gold_unreachable();
3816 }
3817
3818 // The mapping of input section name prefixes to output section names.
3819 // In some cases one prefix is itself a prefix of another prefix; in
3820 // such a case the longer prefix must come first.  These prefixes are
3821 // based on the GNU linker default ELF linker script.
3822
3823 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
3824 const Layout::Section_name_mapping Layout::section_name_mapping[] =
3825 {
3826   MAPPING_INIT(".text.", ".text"),
3827   MAPPING_INIT(".ctors.", ".ctors"),
3828   MAPPING_INIT(".dtors.", ".dtors"),
3829   MAPPING_INIT(".rodata.", ".rodata"),
3830   MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
3831   MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
3832   MAPPING_INIT(".data.", ".data"),
3833   MAPPING_INIT(".bss.", ".bss"),
3834   MAPPING_INIT(".tdata.", ".tdata"),
3835   MAPPING_INIT(".tbss.", ".tbss"),
3836   MAPPING_INIT(".init_array.", ".init_array"),
3837   MAPPING_INIT(".fini_array.", ".fini_array"),
3838   MAPPING_INIT(".sdata.", ".sdata"),
3839   MAPPING_INIT(".sbss.", ".sbss"),
3840   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
3841   // differently depending on whether it is creating a shared library.
3842   MAPPING_INIT(".sdata2.", ".sdata"),
3843   MAPPING_INIT(".sbss2.", ".sbss"),
3844   MAPPING_INIT(".lrodata.", ".lrodata"),
3845   MAPPING_INIT(".ldata.", ".ldata"),
3846   MAPPING_INIT(".lbss.", ".lbss"),
3847   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
3848   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
3849   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
3850   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
3851   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
3852   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
3853   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
3854   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
3855   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
3856   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
3857   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
3858   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
3859   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
3860   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
3861   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
3862   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
3863   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
3864   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
3865   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
3866   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
3867   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
3868 };
3869 #undef MAPPING_INIT
3870
3871 const int Layout::section_name_mapping_count =
3872   (sizeof(Layout::section_name_mapping)
3873    / sizeof(Layout::section_name_mapping[0]));
3874
3875 // Choose the output section name to use given an input section name.
3876 // Set *PLEN to the length of the name.  *PLEN is initialized to the
3877 // length of NAME.
3878
3879 const char*
3880 Layout::output_section_name(const char* name, size_t* plen)
3881 {
3882   // gcc 4.3 generates the following sorts of section names when it
3883   // needs a section name specific to a function:
3884   //   .text.FN
3885   //   .rodata.FN
3886   //   .sdata2.FN
3887   //   .data.FN
3888   //   .data.rel.FN
3889   //   .data.rel.local.FN
3890   //   .data.rel.ro.FN
3891   //   .data.rel.ro.local.FN
3892   //   .sdata.FN
3893   //   .bss.FN
3894   //   .sbss.FN
3895   //   .tdata.FN
3896   //   .tbss.FN
3897
3898   // The GNU linker maps all of those to the part before the .FN,
3899   // except that .data.rel.local.FN is mapped to .data, and
3900   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
3901   // beginning with .data.rel.ro.local are grouped together.
3902
3903   // For an anonymous namespace, the string FN can contain a '.'.
3904
3905   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
3906   // GNU linker maps to .rodata.
3907
3908   // The .data.rel.ro sections are used with -z relro.  The sections
3909   // are recognized by name.  We use the same names that the GNU
3910   // linker does for these sections.
3911
3912   // It is hard to handle this in a principled way, so we don't even
3913   // try.  We use a table of mappings.  If the input section name is
3914   // not found in the table, we simply use it as the output section
3915   // name.
3916
3917   const Section_name_mapping* psnm = section_name_mapping;
3918   for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
3919     {
3920       if (strncmp(name, psnm->from, psnm->fromlen) == 0)
3921         {
3922           *plen = psnm->tolen;
3923           return psnm->to;
3924         }
3925     }
3926
3927   // Compressed debug sections should be mapped to the corresponding
3928   // uncompressed section.
3929   if (is_compressed_debug_section(name))
3930     {
3931       size_t len = strlen(name);
3932       char* uncompressed_name = new char[len];
3933       uncompressed_name[0] = '.';
3934       gold_assert(name[0] == '.' && name[1] == 'z');
3935       strncpy(&uncompressed_name[1], &name[2], len - 2);
3936       uncompressed_name[len - 1] = '\0';
3937       *plen = len - 1;
3938       return uncompressed_name;
3939     }
3940
3941   return name;
3942 }
3943
3944 // Check if a comdat group or .gnu.linkonce section with the given
3945 // NAME is selected for the link.  If there is already a section,
3946 // *KEPT_SECTION is set to point to the existing section and the
3947 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
3948 // IS_GROUP_NAME are recorded for this NAME in the layout object,
3949 // *KEPT_SECTION is set to the internal copy and the function returns
3950 // true.
3951
3952 bool
3953 Layout::find_or_add_kept_section(const std::string& name,
3954                                  Relobj* object,
3955                                  unsigned int shndx,
3956                                  bool is_comdat,
3957                                  bool is_group_name,
3958                                  Kept_section** kept_section)
3959 {
3960   // It's normal to see a couple of entries here, for the x86 thunk
3961   // sections.  If we see more than a few, we're linking a C++
3962   // program, and we resize to get more space to minimize rehashing.
3963   if (this->signatures_.size() > 4
3964       && !this->resized_signatures_)
3965     {
3966       reserve_unordered_map(&this->signatures_,
3967                             this->number_of_input_files_ * 64);
3968       this->resized_signatures_ = true;
3969     }
3970
3971   Kept_section candidate;
3972   std::pair<Signatures::iterator, bool> ins =
3973     this->signatures_.insert(std::make_pair(name, candidate));
3974
3975   if (kept_section != NULL)
3976     *kept_section = &ins.first->second;
3977   if (ins.second)
3978     {
3979       // This is the first time we've seen this signature.
3980       ins.first->second.set_object(object);
3981       ins.first->second.set_shndx(shndx);
3982       if (is_comdat)
3983         ins.first->second.set_is_comdat();
3984       if (is_group_name)
3985         ins.first->second.set_is_group_name();
3986       return true;
3987     }
3988
3989   // We have already seen this signature.
3990
3991   if (ins.first->second.is_group_name())
3992     {
3993       // We've already seen a real section group with this signature.
3994       // If the kept group is from a plugin object, and we're in the
3995       // replacement phase, accept the new one as a replacement.
3996       if (ins.first->second.object() == NULL
3997           && parameters->options().plugins()->in_replacement_phase())
3998         {
3999           ins.first->second.set_object(object);
4000           ins.first->second.set_shndx(shndx);
4001           return true;
4002         }
4003       return false;
4004     }
4005   else if (is_group_name)
4006     {
4007       // This is a real section group, and we've already seen a
4008       // linkonce section with this signature.  Record that we've seen
4009       // a section group, and don't include this section group.
4010       ins.first->second.set_is_group_name();
4011       return false;
4012     }
4013   else
4014     {
4015       // We've already seen a linkonce section and this is a linkonce
4016       // section.  These don't block each other--this may be the same
4017       // symbol name with different section types.
4018       return true;
4019     }
4020 }
4021
4022 // Store the allocated sections into the section list.
4023
4024 void
4025 Layout::get_allocated_sections(Section_list* section_list) const
4026 {
4027   for (Section_list::const_iterator p = this->section_list_.begin();
4028        p != this->section_list_.end();
4029        ++p)
4030     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4031       section_list->push_back(*p);
4032 }
4033
4034 // Create an output segment.
4035
4036 Output_segment*
4037 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4038 {
4039   gold_assert(!parameters->options().relocatable());
4040   Output_segment* oseg = new Output_segment(type, flags);
4041   this->segment_list_.push_back(oseg);
4042
4043   if (type == elfcpp::PT_TLS)
4044     this->tls_segment_ = oseg;
4045   else if (type == elfcpp::PT_GNU_RELRO)
4046     this->relro_segment_ = oseg;
4047
4048   return oseg;
4049 }
4050
4051 // Write out the Output_sections.  Most won't have anything to write,
4052 // since most of the data will come from input sections which are
4053 // handled elsewhere.  But some Output_sections do have Output_data.
4054
4055 void
4056 Layout::write_output_sections(Output_file* of) const
4057 {
4058   for (Section_list::const_iterator p = this->section_list_.begin();
4059        p != this->section_list_.end();
4060        ++p)
4061     {
4062       if (!(*p)->after_input_sections())
4063         (*p)->write(of);
4064     }
4065 }
4066
4067 // Write out data not associated with a section or the symbol table.
4068
4069 void
4070 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4071 {
4072   if (!parameters->options().strip_all())
4073     {
4074       const Output_section* symtab_section = this->symtab_section_;
4075       for (Section_list::const_iterator p = this->section_list_.begin();
4076            p != this->section_list_.end();
4077            ++p)
4078         {
4079           if ((*p)->needs_symtab_index())
4080             {
4081               gold_assert(symtab_section != NULL);
4082               unsigned int index = (*p)->symtab_index();
4083               gold_assert(index > 0 && index != -1U);
4084               off_t off = (symtab_section->offset()
4085                            + index * symtab_section->entsize());
4086               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4087             }
4088         }
4089     }
4090
4091   const Output_section* dynsym_section = this->dynsym_section_;
4092   for (Section_list::const_iterator p = this->section_list_.begin();
4093        p != this->section_list_.end();
4094        ++p)
4095     {
4096       if ((*p)->needs_dynsym_index())
4097         {
4098           gold_assert(dynsym_section != NULL);
4099           unsigned int index = (*p)->dynsym_index();
4100           gold_assert(index > 0 && index != -1U);
4101           off_t off = (dynsym_section->offset()
4102                        + index * dynsym_section->entsize());
4103           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4104         }
4105     }
4106
4107   // Write out the Output_data which are not in an Output_section.
4108   for (Data_list::const_iterator p = this->special_output_list_.begin();
4109        p != this->special_output_list_.end();
4110        ++p)
4111     (*p)->write(of);
4112 }
4113
4114 // Write out the Output_sections which can only be written after the
4115 // input sections are complete.
4116
4117 void
4118 Layout::write_sections_after_input_sections(Output_file* of)
4119 {
4120   // Determine the final section offsets, and thus the final output
4121   // file size.  Note we finalize the .shstrab last, to allow the
4122   // after_input_section sections to modify their section-names before
4123   // writing.
4124   if (this->any_postprocessing_sections_)
4125     {
4126       off_t off = this->output_file_size_;
4127       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4128
4129       // Now that we've finalized the names, we can finalize the shstrab.
4130       off =
4131         this->set_section_offsets(off,
4132                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4133
4134       if (off > this->output_file_size_)
4135         {
4136           of->resize(off);
4137           this->output_file_size_ = off;
4138         }
4139     }
4140
4141   for (Section_list::const_iterator p = this->section_list_.begin();
4142        p != this->section_list_.end();
4143        ++p)
4144     {
4145       if ((*p)->after_input_sections())
4146         (*p)->write(of);
4147     }
4148
4149   this->section_headers_->write(of);
4150 }
4151
4152 // If the build ID requires computing a checksum, do so here, and
4153 // write it out.  We compute a checksum over the entire file because
4154 // that is simplest.
4155
4156 void
4157 Layout::write_build_id(Output_file* of) const
4158 {
4159   if (this->build_id_note_ == NULL)
4160     return;
4161
4162   const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4163
4164   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4165                                           this->build_id_note_->data_size());
4166
4167   const char* style = parameters->options().build_id();
4168   if (strcmp(style, "sha1") == 0)
4169     {
4170       sha1_ctx ctx;
4171       sha1_init_ctx(&ctx);
4172       sha1_process_bytes(iv, this->output_file_size_, &ctx);
4173       sha1_finish_ctx(&ctx, ov);
4174     }
4175   else if (strcmp(style, "md5") == 0)
4176     {
4177       md5_ctx ctx;
4178       md5_init_ctx(&ctx);
4179       md5_process_bytes(iv, this->output_file_size_, &ctx);
4180       md5_finish_ctx(&ctx, ov);
4181     }
4182   else
4183     gold_unreachable();
4184
4185   of->write_output_view(this->build_id_note_->offset(),
4186                         this->build_id_note_->data_size(),
4187                         ov);
4188
4189   of->free_input_view(0, this->output_file_size_, iv);
4190 }
4191
4192 // Write out a binary file.  This is called after the link is
4193 // complete.  IN is the temporary output file we used to generate the
4194 // ELF code.  We simply walk through the segments, read them from
4195 // their file offset in IN, and write them to their load address in
4196 // the output file.  FIXME: with a bit more work, we could support
4197 // S-records and/or Intel hex format here.
4198
4199 void
4200 Layout::write_binary(Output_file* in) const
4201 {
4202   gold_assert(parameters->options().oformat_enum()
4203               == General_options::OBJECT_FORMAT_BINARY);
4204
4205   // Get the size of the binary file.
4206   uint64_t max_load_address = 0;
4207   for (Segment_list::const_iterator p = this->segment_list_.begin();
4208        p != this->segment_list_.end();
4209        ++p)
4210     {
4211       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4212         {
4213           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4214           if (max_paddr > max_load_address)
4215             max_load_address = max_paddr;
4216         }
4217     }
4218
4219   Output_file out(parameters->options().output_file_name());
4220   out.open(max_load_address);
4221
4222   for (Segment_list::const_iterator p = this->segment_list_.begin();
4223        p != this->segment_list_.end();
4224        ++p)
4225     {
4226       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4227         {
4228           const unsigned char* vin = in->get_input_view((*p)->offset(),
4229                                                         (*p)->filesz());
4230           unsigned char* vout = out.get_output_view((*p)->paddr(),
4231                                                     (*p)->filesz());
4232           memcpy(vout, vin, (*p)->filesz());
4233           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4234           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4235         }
4236     }
4237
4238   out.close();
4239 }
4240
4241 // Print the output sections to the map file.
4242
4243 void
4244 Layout::print_to_mapfile(Mapfile* mapfile) const
4245 {
4246   for (Segment_list::const_iterator p = this->segment_list_.begin();
4247        p != this->segment_list_.end();
4248        ++p)
4249     (*p)->print_sections_to_mapfile(mapfile);
4250 }
4251
4252 // Print statistical information to stderr.  This is used for --stats.
4253
4254 void
4255 Layout::print_stats() const
4256 {
4257   this->namepool_.print_stats("section name pool");
4258   this->sympool_.print_stats("output symbol name pool");
4259   this->dynpool_.print_stats("dynamic name pool");
4260
4261   for (Section_list::const_iterator p = this->section_list_.begin();
4262        p != this->section_list_.end();
4263        ++p)
4264     (*p)->print_merge_stats();
4265 }
4266
4267 // Write_sections_task methods.
4268
4269 // We can always run this task.
4270
4271 Task_token*
4272 Write_sections_task::is_runnable()
4273 {
4274   return NULL;
4275 }
4276
4277 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4278 // when finished.
4279
4280 void
4281 Write_sections_task::locks(Task_locker* tl)
4282 {
4283   tl->add(this, this->output_sections_blocker_);
4284   tl->add(this, this->final_blocker_);
4285 }
4286
4287 // Run the task--write out the data.
4288
4289 void
4290 Write_sections_task::run(Workqueue*)
4291 {
4292   this->layout_->write_output_sections(this->of_);
4293 }
4294
4295 // Write_data_task methods.
4296
4297 // We can always run this task.
4298
4299 Task_token*
4300 Write_data_task::is_runnable()
4301 {
4302   return NULL;
4303 }
4304
4305 // We need to unlock FINAL_BLOCKER when finished.
4306
4307 void
4308 Write_data_task::locks(Task_locker* tl)
4309 {
4310   tl->add(this, this->final_blocker_);
4311 }
4312
4313 // Run the task--write out the data.
4314
4315 void
4316 Write_data_task::run(Workqueue*)
4317 {
4318   this->layout_->write_data(this->symtab_, this->of_);
4319 }
4320
4321 // Write_symbols_task methods.
4322
4323 // We can always run this task.
4324
4325 Task_token*
4326 Write_symbols_task::is_runnable()
4327 {
4328   return NULL;
4329 }
4330
4331 // We need to unlock FINAL_BLOCKER when finished.
4332
4333 void
4334 Write_symbols_task::locks(Task_locker* tl)
4335 {
4336   tl->add(this, this->final_blocker_);
4337 }
4338
4339 // Run the task--write out the symbols.
4340
4341 void
4342 Write_symbols_task::run(Workqueue*)
4343 {
4344   this->symtab_->write_globals(this->sympool_, this->dynpool_,
4345                                this->layout_->symtab_xindex(),
4346                                this->layout_->dynsym_xindex(), this->of_);
4347 }
4348
4349 // Write_after_input_sections_task methods.
4350
4351 // We can only run this task after the input sections have completed.
4352
4353 Task_token*
4354 Write_after_input_sections_task::is_runnable()
4355 {
4356   if (this->input_sections_blocker_->is_blocked())
4357     return this->input_sections_blocker_;
4358   return NULL;
4359 }
4360
4361 // We need to unlock FINAL_BLOCKER when finished.
4362
4363 void
4364 Write_after_input_sections_task::locks(Task_locker* tl)
4365 {
4366   tl->add(this, this->final_blocker_);
4367 }
4368
4369 // Run the task.
4370
4371 void
4372 Write_after_input_sections_task::run(Workqueue*)
4373 {
4374   this->layout_->write_sections_after_input_sections(this->of_);
4375 }
4376
4377 // Close_task_runner methods.
4378
4379 // Run the task--close the file.
4380
4381 void
4382 Close_task_runner::run(Workqueue*, const Task*)
4383 {
4384   // If we need to compute a checksum for the BUILD if, we do so here.
4385   this->layout_->write_build_id(this->of_);
4386
4387   // If we've been asked to create a binary file, we do so here.
4388   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
4389     this->layout_->write_binary(this->of_);
4390
4391   this->of_->close();
4392 }
4393
4394 // Instantiate the templates we need.  We could use the configure
4395 // script to restrict this to only the ones for implemented targets.
4396
4397 #ifdef HAVE_TARGET_32_LITTLE
4398 template
4399 Output_section*
4400 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
4401                           const char* name,
4402                           const elfcpp::Shdr<32, false>& shdr,
4403                           unsigned int, unsigned int, off_t*);
4404 #endif
4405
4406 #ifdef HAVE_TARGET_32_BIG
4407 template
4408 Output_section*
4409 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
4410                          const char* name,
4411                          const elfcpp::Shdr<32, true>& shdr,
4412                          unsigned int, unsigned int, off_t*);
4413 #endif
4414
4415 #ifdef HAVE_TARGET_64_LITTLE
4416 template
4417 Output_section*
4418 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
4419                           const char* name,
4420                           const elfcpp::Shdr<64, false>& shdr,
4421                           unsigned int, unsigned int, off_t*);
4422 #endif
4423
4424 #ifdef HAVE_TARGET_64_BIG
4425 template
4426 Output_section*
4427 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
4428                          const char* name,
4429                          const elfcpp::Shdr<64, true>& shdr,
4430                          unsigned int, unsigned int, off_t*);
4431 #endif
4432
4433 #ifdef HAVE_TARGET_32_LITTLE
4434 template
4435 Output_section*
4436 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
4437                                 unsigned int reloc_shndx,
4438                                 const elfcpp::Shdr<32, false>& shdr,
4439                                 Output_section* data_section,
4440                                 Relocatable_relocs* rr);
4441 #endif
4442
4443 #ifdef HAVE_TARGET_32_BIG
4444 template
4445 Output_section*
4446 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
4447                                unsigned int reloc_shndx,
4448                                const elfcpp::Shdr<32, true>& shdr,
4449                                Output_section* data_section,
4450                                Relocatable_relocs* rr);
4451 #endif
4452
4453 #ifdef HAVE_TARGET_64_LITTLE
4454 template
4455 Output_section*
4456 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
4457                                 unsigned int reloc_shndx,
4458                                 const elfcpp::Shdr<64, false>& shdr,
4459                                 Output_section* data_section,
4460                                 Relocatable_relocs* rr);
4461 #endif
4462
4463 #ifdef HAVE_TARGET_64_BIG
4464 template
4465 Output_section*
4466 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
4467                                unsigned int reloc_shndx,
4468                                const elfcpp::Shdr<64, true>& shdr,
4469                                Output_section* data_section,
4470                                Relocatable_relocs* rr);
4471 #endif
4472
4473 #ifdef HAVE_TARGET_32_LITTLE
4474 template
4475 void
4476 Layout::layout_group<32, false>(Symbol_table* symtab,
4477                                 Sized_relobj<32, false>* object,
4478                                 unsigned int,
4479                                 const char* group_section_name,
4480                                 const char* signature,
4481                                 const elfcpp::Shdr<32, false>& shdr,
4482                                 elfcpp::Elf_Word flags,
4483                                 std::vector<unsigned int>* shndxes);
4484 #endif
4485
4486 #ifdef HAVE_TARGET_32_BIG
4487 template
4488 void
4489 Layout::layout_group<32, true>(Symbol_table* symtab,
4490                                Sized_relobj<32, true>* object,
4491                                unsigned int,
4492                                const char* group_section_name,
4493                                const char* signature,
4494                                const elfcpp::Shdr<32, true>& shdr,
4495                                elfcpp::Elf_Word flags,
4496                                std::vector<unsigned int>* shndxes);
4497 #endif
4498
4499 #ifdef HAVE_TARGET_64_LITTLE
4500 template
4501 void
4502 Layout::layout_group<64, false>(Symbol_table* symtab,
4503                                 Sized_relobj<64, false>* object,
4504                                 unsigned int,
4505                                 const char* group_section_name,
4506                                 const char* signature,
4507                                 const elfcpp::Shdr<64, false>& shdr,
4508                                 elfcpp::Elf_Word flags,
4509                                 std::vector<unsigned int>* shndxes);
4510 #endif
4511
4512 #ifdef HAVE_TARGET_64_BIG
4513 template
4514 void
4515 Layout::layout_group<64, true>(Symbol_table* symtab,
4516                                Sized_relobj<64, true>* object,
4517                                unsigned int,
4518                                const char* group_section_name,
4519                                const char* signature,
4520                                const elfcpp::Shdr<64, true>& shdr,
4521                                elfcpp::Elf_Word flags,
4522                                std::vector<unsigned int>* shndxes);
4523 #endif
4524
4525 #ifdef HAVE_TARGET_32_LITTLE
4526 template
4527 Output_section*
4528 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
4529                                    const unsigned char* symbols,
4530                                    off_t symbols_size,
4531                                    const unsigned char* symbol_names,
4532                                    off_t symbol_names_size,
4533                                    unsigned int shndx,
4534                                    const elfcpp::Shdr<32, false>& shdr,
4535                                    unsigned int reloc_shndx,
4536                                    unsigned int reloc_type,
4537                                    off_t* off);
4538 #endif
4539
4540 #ifdef HAVE_TARGET_32_BIG
4541 template
4542 Output_section*
4543 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
4544                                    const unsigned char* symbols,
4545                                    off_t symbols_size,
4546                                   const unsigned char* symbol_names,
4547                                   off_t symbol_names_size,
4548                                   unsigned int shndx,
4549                                   const elfcpp::Shdr<32, true>& shdr,
4550                                   unsigned int reloc_shndx,
4551                                   unsigned int reloc_type,
4552                                   off_t* off);
4553 #endif
4554
4555 #ifdef HAVE_TARGET_64_LITTLE
4556 template
4557 Output_section*
4558 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
4559                                    const unsigned char* symbols,
4560                                    off_t symbols_size,
4561                                    const unsigned char* symbol_names,
4562                                    off_t symbol_names_size,
4563                                    unsigned int shndx,
4564                                    const elfcpp::Shdr<64, false>& shdr,
4565                                    unsigned int reloc_shndx,
4566                                    unsigned int reloc_type,
4567                                    off_t* off);
4568 #endif
4569
4570 #ifdef HAVE_TARGET_64_BIG
4571 template
4572 Output_section*
4573 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
4574                                    const unsigned char* symbols,
4575                                    off_t symbols_size,
4576                                   const unsigned char* symbol_names,
4577                                   off_t symbol_names_size,
4578                                   unsigned int shndx,
4579                                   const elfcpp::Shdr<64, true>& shdr,
4580                                   unsigned int reloc_shndx,
4581                                   unsigned int reloc_type,
4582                                   off_t* off);
4583 #endif
4584
4585 } // End namespace gold.