gold/output.cc

   1 // output.cc -- manage the output file for gold
   2
   3 // Copyright 2006, 2007 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstdlib>
  26 #include <cerrno>
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <algorithm>
  32 #include "libiberty.h"   // for unlink_if_ordinary()
  33
  34 #include "parameters.h"
  35 #include "object.h"
  36 #include "symtab.h"
  37 #include "reloc.h"
  38 #include "merge.h"
  39 #include "output.h"
  40
  41 namespace gold
  42 {
  43
  44 // Output_data variables.
  45
  46 bool Output_data::sizes_are_fixed;
  47
  48 // Output_data methods.
  49
  50 Output_data::~Output_data()
  51 {
  52 }
  53
  54 // Set the address and offset.
  55
  56 void
  57 Output_data::set_address(uint64_t addr, off_t off)
  58 {
  59   this->address_ = addr;
  60   this->offset_ = off;
  61
  62   // Let the child class know.
  63   this->do_set_address(addr, off);
  64 }
  65
  66 // Return the default alignment for the target size.
  67
  68 uint64_t
  69 Output_data::default_alignment()
  70 {
  71   return Output_data::default_alignment_for_size(parameters->get_size());
  72 }
  73
  74 // Return the default alignment for a size--32 or 64.
  75
  76 uint64_t
  77 Output_data::default_alignment_for_size(int size)
  78 {
  79   if (size == 32)
  80     return 4;
  81   else if (size == 64)
  82     return 8;
  83   else
  84     gold_unreachable();
  85 }
  86
  87 // Output_section_header methods.  This currently assumes that the
  88 // segment and section lists are complete at construction time.
  89
  90 Output_section_headers::Output_section_headers(
  91     const Layout* layout,
  92     const Layout::Segment_list* segment_list,
  93     const Layout::Section_list* unattached_section_list,
  94     const Stringpool* secnamepool)
  95   : layout_(layout),
  96     segment_list_(segment_list),
  97     unattached_section_list_(unattached_section_list),
  98     secnamepool_(secnamepool)
  99 {
 100   // Count all the sections.  Start with 1 for the null section.
 101   off_t count = 1;
 102   for (Layout::Segment_list::const_iterator p = segment_list->begin();
 103        p != segment_list->end();
 104        ++p)
 105     if ((*p)->type() == elfcpp::PT_LOAD)
 106       count += (*p)->output_section_count();
 107   count += unattached_section_list->size();
 108
 109   const int size = parameters->get_size();
 110   int shdr_size;
 111   if (size == 32)
 112     shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
 113   else if (size == 64)
 114     shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
 115   else
 116     gold_unreachable();
 117
 118   this->set_data_size(count * shdr_size);
 119 }
 120
 121 // Write out the section headers.
 122
 123 void
 124 Output_section_headers::do_write(Output_file* of)
 125 {
 126   if (parameters->get_size() == 32)
 127     {
 128       if (parameters->is_big_endian())
 129         {
 130 #ifdef HAVE_TARGET_32_BIG
 131           this->do_sized_write<32, true>(of);
 132 #else
 133           gold_unreachable();
 134 #endif
 135         }
 136       else
 137         {
 138 #ifdef HAVE_TARGET_32_LITTLE
 139           this->do_sized_write<32, false>(of);
 140 #else
 141           gold_unreachable();
 142 #endif
 143         }
 144     }
 145   else if (parameters->get_size() == 64)
 146     {
 147       if (parameters->is_big_endian())
 148         {
 149 #ifdef HAVE_TARGET_64_BIG
 150           this->do_sized_write<64, true>(of);
 151 #else
 152           gold_unreachable();
 153 #endif
 154         }
 155       else
 156         {
 157 #ifdef HAVE_TARGET_64_LITTLE
 158           this->do_sized_write<64, false>(of);
 159 #else
 160           gold_unreachable();
 161 #endif
 162         }
 163     }
 164   else
 165     gold_unreachable();
 166 }
 167
 168 template<int size, bool big_endian>
 169 void
 170 Output_section_headers::do_sized_write(Output_file* of)
 171 {
 172   off_t all_shdrs_size = this->data_size();
 173   unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
 174
 175   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 176   unsigned char* v = view;
 177
 178   {
 179     typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
 180     oshdr.put_sh_name(0);
 181     oshdr.put_sh_type(elfcpp::SHT_NULL);
 182     oshdr.put_sh_flags(0);
 183     oshdr.put_sh_addr(0);
 184     oshdr.put_sh_offset(0);
 185     oshdr.put_sh_size(0);
 186     oshdr.put_sh_link(0);
 187     oshdr.put_sh_info(0);
 188     oshdr.put_sh_addralign(0);
 189     oshdr.put_sh_entsize(0);
 190   }
 191
 192   v += shdr_size;
 193
 194   unsigned shndx = 1;
 195   for (Layout::Segment_list::const_iterator p = this->segment_list_->begin();
 196        p != this->segment_list_->end();
 197        ++p)
 198     v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
 199             this->layout_, this->secnamepool_, v, &shndx
 200             SELECT_SIZE_ENDIAN(size, big_endian));
 201   for (Layout::Section_list::const_iterator p =
 202          this->unattached_section_list_->begin();
 203        p != this->unattached_section_list_->end();
 204        ++p)
 205     {
 206       gold_assert(shndx == (*p)->out_shndx());
 207       elfcpp::Shdr_write<size, big_endian> oshdr(v);
 208       (*p)->write_header(this->layout_, this->secnamepool_, &oshdr);
 209       v += shdr_size;
 210       ++shndx;
 211     }
 212
 213   of->write_output_view(this->offset(), all_shdrs_size, view);
 214 }
 215
 216 // Output_segment_header methods.
 217
 218 Output_segment_headers::Output_segment_headers(
 219     const Layout::Segment_list& segment_list)
 220   : segment_list_(segment_list)
 221 {
 222   const int size = parameters->get_size();
 223   int phdr_size;
 224   if (size == 32)
 225     phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
 226   else if (size == 64)
 227     phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
 228   else
 229     gold_unreachable();
 230
 231   this->set_data_size(segment_list.size() * phdr_size);
 232 }
 233
 234 void
 235 Output_segment_headers::do_write(Output_file* of)
 236 {
 237   if (parameters->get_size() == 32)
 238     {
 239       if (parameters->is_big_endian())
 240         {
 241 #ifdef HAVE_TARGET_32_BIG
 242           this->do_sized_write<32, true>(of);
 243 #else
 244           gold_unreachable();
 245 #endif
 246         }
 247       else
 248         {
 249 #ifdef HAVE_TARGET_32_LITTLE
 250         this->do_sized_write<32, false>(of);
 251 #else
 252         gold_unreachable();
 253 #endif
 254         }
 255     }
 256   else if (parameters->get_size() == 64)
 257     {
 258       if (parameters->is_big_endian())
 259         {
 260 #ifdef HAVE_TARGET_64_BIG
 261           this->do_sized_write<64, true>(of);
 262 #else
 263           gold_unreachable();
 264 #endif
 265         }
 266       else
 267         {
 268 #ifdef HAVE_TARGET_64_LITTLE
 269           this->do_sized_write<64, false>(of);
 270 #else
 271           gold_unreachable();
 272 #endif
 273         }
 274     }
 275   else
 276     gold_unreachable();
 277 }
 278
 279 template<int size, bool big_endian>
 280 void
 281 Output_segment_headers::do_sized_write(Output_file* of)
 282 {
 283   const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
 284   off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
 285   unsigned char* view = of->get_output_view(this->offset(),
 286                                             all_phdrs_size);
 287   unsigned char* v = view;
 288   for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
 289        p != this->segment_list_.end();
 290        ++p)
 291     {
 292       elfcpp::Phdr_write<size, big_endian> ophdr(v);
 293       (*p)->write_header(&ophdr);
 294       v += phdr_size;
 295     }
 296
 297   of->write_output_view(this->offset(), all_phdrs_size, view);
 298 }
 299
 300 // Output_file_header methods.
 301
 302 Output_file_header::Output_file_header(const Target* target,
 303                                        const Symbol_table* symtab,
 304                                        const Output_segment_headers* osh)
 305   : target_(target),
 306     symtab_(symtab),
 307     segment_header_(osh),
 308     section_header_(NULL),
 309     shstrtab_(NULL)
 310 {
 311   const int size = parameters->get_size();
 312   int ehdr_size;
 313   if (size == 32)
 314     ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
 315   else if (size == 64)
 316     ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
 317   else
 318     gold_unreachable();
 319
 320   this->set_data_size(ehdr_size);
 321 }
 322
 323 // Set the section table information for a file header.
 324
 325 void
 326 Output_file_header::set_section_info(const Output_section_headers* shdrs,
 327                                      const Output_section* shstrtab)
 328 {
 329   this->section_header_ = shdrs;
 330   this->shstrtab_ = shstrtab;
 331 }
 332
 333 // Write out the file header.
 334
 335 void
 336 Output_file_header::do_write(Output_file* of)
 337 {
 338   if (parameters->get_size() == 32)
 339     {
 340       if (parameters->is_big_endian())
 341         {
 342 #ifdef HAVE_TARGET_32_BIG
 343           this->do_sized_write<32, true>(of);
 344 #else
 345           gold_unreachable();
 346 #endif
 347         }
 348       else
 349         {
 350 #ifdef HAVE_TARGET_32_LITTLE
 351           this->do_sized_write<32, false>(of);
 352 #else
 353           gold_unreachable();
 354 #endif
 355         }
 356     }
 357   else if (parameters->get_size() == 64)
 358     {
 359       if (parameters->is_big_endian())
 360         {
 361 #ifdef HAVE_TARGET_64_BIG
 362           this->do_sized_write<64, true>(of);
 363 #else
 364           gold_unreachable();
 365 #endif
 366         }
 367       else
 368         {
 369 #ifdef HAVE_TARGET_64_LITTLE
 370           this->do_sized_write<64, false>(of);
 371 #else
 372           gold_unreachable();
 373 #endif
 374         }
 375     }
 376   else
 377     gold_unreachable();
 378 }
 379
 380 // Write out the file header with appropriate size and endianess.
 381
 382 template<int size, bool big_endian>
 383 void
 384 Output_file_header::do_sized_write(Output_file* of)
 385 {
 386   gold_assert(this->offset() == 0);
 387
 388   int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
 389   unsigned char* view = of->get_output_view(0, ehdr_size);
 390   elfcpp::Ehdr_write<size, big_endian> oehdr(view);
 391
 392   unsigned char e_ident[elfcpp::EI_NIDENT];
 393   memset(e_ident, 0, elfcpp::EI_NIDENT);
 394   e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
 395   e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
 396   e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
 397   e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
 398   if (size == 32)
 399     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
 400   else if (size == 64)
 401     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
 402   else
 403     gold_unreachable();
 404   e_ident[elfcpp::EI_DATA] = (big_endian
 405                               ? elfcpp::ELFDATA2MSB
 406                               : elfcpp::ELFDATA2LSB);
 407   e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
 408   // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
 409   oehdr.put_e_ident(e_ident);
 410
 411   elfcpp::ET e_type;
 412   if (parameters->output_is_object())
 413     e_type = elfcpp::ET_REL;
 414   else if (parameters->output_is_shared())
 415     e_type = elfcpp::ET_DYN;
 416   else
 417     e_type = elfcpp::ET_EXEC;
 418   oehdr.put_e_type(e_type);
 419
 420   oehdr.put_e_machine(this->target_->machine_code());
 421   oehdr.put_e_version(elfcpp::EV_CURRENT);
 422
 423   // FIXME: Need to support -e, and target specific entry symbol.
 424   Symbol* sym = this->symtab_->lookup("_start");
 425   typename Sized_symbol<size>::Value_type v;
 426   if (sym == NULL)
 427     v = 0;
 428   else
 429     {
 430       Sized_symbol<size>* ssym;
 431       ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME(size) (
 432         sym SELECT_SIZE(size));
 433       v = ssym->value();
 434     }
 435   oehdr.put_e_entry(v);
 436
 437   oehdr.put_e_phoff(this->segment_header_->offset());
 438   oehdr.put_e_shoff(this->section_header_->offset());
 439
 440   // FIXME: The target needs to set the flags.
 441   oehdr.put_e_flags(0);
 442
 443   oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
 444   oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
 445   oehdr.put_e_phnum(this->segment_header_->data_size()
 446                      / elfcpp::Elf_sizes<size>::phdr_size);
 447   oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
 448   oehdr.put_e_shnum(this->section_header_->data_size()
 449                      / elfcpp::Elf_sizes<size>::shdr_size);
 450   oehdr.put_e_shstrndx(this->shstrtab_->out_shndx());
 451
 452   of->write_output_view(0, ehdr_size, view);
 453 }
 454
 455 // Output_data_const methods.
 456
 457 void
 458 Output_data_const::do_write(Output_file* of)
 459 {
 460   of->write(this->offset(), this->data_.data(), this->data_.size());
 461 }
 462
 463 // Output_data_const_buffer methods.
 464
 465 void
 466 Output_data_const_buffer::do_write(Output_file* of)
 467 {
 468   of->write(this->offset(), this->p_, this->data_size());
 469 }
 470
 471 // Output_section_data methods.
 472
 473 // Record the output section, and set the entry size and such.
 474
 475 void
 476 Output_section_data::set_output_section(Output_section* os)
 477 {
 478   gold_assert(this->output_section_ == NULL);
 479   this->output_section_ = os;
 480   this->do_adjust_output_section(os);
 481 }
 482
 483 // Return the section index of the output section.
 484
 485 unsigned int
 486 Output_section_data::do_out_shndx() const
 487 {
 488   gold_assert(this->output_section_ != NULL);
 489   return this->output_section_->out_shndx();
 490 }
 491
 492 // Output_data_strtab methods.
 493
 494 // Set the address.  We don't actually care about the address, but we
 495 // do set our final size.
 496
 497 void
 498 Output_data_strtab::do_set_address(uint64_t, off_t)
 499 {
 500   this->strtab_->set_string_offsets();
 501   this->set_data_size(this->strtab_->get_strtab_size());
 502 }
 503
 504 // Write out a string table.
 505
 506 void
 507 Output_data_strtab::do_write(Output_file* of)
 508 {
 509   this->strtab_->write(of, this->offset());
 510 }
 511
 512 // Output_reloc methods.
 513
 514 // Get the symbol index of a relocation.
 515
 516 template<bool dynamic, int size, bool big_endian>
 517 unsigned int
 518 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
 519   const
 520 {
 521   unsigned int index;
 522   switch (this->local_sym_index_)
 523     {
 524     case INVALID_CODE:
 525       gold_unreachable();
 526
 527     case GSYM_CODE:
 528       if (this->u1_.gsym == NULL)
 529         index = 0;
 530       else if (dynamic)
 531         index = this->u1_.gsym->dynsym_index();
 532       else
 533         index = this->u1_.gsym->symtab_index();
 534       break;
 535
 536     case SECTION_CODE:
 537       if (dynamic)
 538         index = this->u1_.os->dynsym_index();
 539       else
 540         index = this->u1_.os->symtab_index();
 541       break;
 542
 543     case 0:
 544       // Relocations without symbols use a symbol index of 0.
 545       index = 0;
 546       break;
 547
 548     default:
 549       if (dynamic)
 550         {
 551           // FIXME: It seems that some targets may need to generate
 552           // dynamic relocations against local symbols for some
 553           // reasons.  This will have to be addressed at some point.
 554           gold_unreachable();
 555         }
 556       else
 557         index = this->u1_.relobj->symtab_index(this->local_sym_index_);
 558       break;
 559     }
 560   gold_assert(index != -1U);
 561   return index;
 562 }
 563
 564 // Write out the offset and info fields of a Rel or Rela relocation
 565 // entry.
 566
 567 template<bool dynamic, int size, bool big_endian>
 568 template<typename Write_rel>
 569 void
 570 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel(
 571     Write_rel* wr) const
 572 {
 573   Address address = this->address_;
 574   if (this->shndx_ != INVALID_CODE)
 575     {
 576       off_t off;
 577       Output_section* os = this->u2_.relobj->output_section(this->shndx_,
 578                                                             &off);
 579       gold_assert(os != NULL);
 580       if (off != -1)
 581         address += os->address() + off;
 582       else
 583         {
 584           address = os->output_address(this->u2_.relobj, this->shndx_,
 585                                        address);
 586           gold_assert(address != -1U);
 587         }
 588     }
 589   else if (this->u2_.od != NULL)
 590     address += this->u2_.od->address();
 591   wr->put_r_offset(address);
 592   wr->put_r_info(elfcpp::elf_r_info<size>(this->get_symbol_index(),
 593                                           this->type_));
 594 }
 595
 596 // Write out a Rel relocation.
 597
 598 template<bool dynamic, int size, bool big_endian>
 599 void
 600 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write(
 601     unsigned char* pov) const
 602 {
 603   elfcpp::Rel_write<size, big_endian> orel(pov);
 604   this->write_rel(&orel);
 605 }
 606
 607 // Write out a Rela relocation.
 608
 609 template<bool dynamic, int size, bool big_endian>
 610 void
 611 Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write(
 612     unsigned char* pov) const
 613 {
 614   elfcpp::Rela_write<size, big_endian> orel(pov);
 615   this->rel_.write_rel(&orel);
 616   orel.put_r_addend(this->addend_);
 617 }
 618
 619 // Output_data_reloc_base methods.
 620
 621 // Adjust the output section.
 622
 623 template<int sh_type, bool dynamic, int size, bool big_endian>
 624 void
 625 Output_data_reloc_base<sh_type, dynamic, size, big_endian>
 626     ::do_adjust_output_section(Output_section* os)
 627 {
 628   if (sh_type == elfcpp::SHT_REL)
 629     os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
 630   else if (sh_type == elfcpp::SHT_RELA)
 631     os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
 632   else
 633     gold_unreachable();
 634   if (dynamic)
 635     os->set_should_link_to_dynsym();
 636   else
 637     os->set_should_link_to_symtab();
 638 }
 639
 640 // Write out relocation data.
 641
 642 template<int sh_type, bool dynamic, int size, bool big_endian>
 643 void
 644 Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write(
 645     Output_file* of)
 646 {
 647   const off_t off = this->offset();
 648   const off_t oview_size = this->data_size();
 649   unsigned char* const oview = of->get_output_view(off, oview_size);
 650
 651   unsigned char* pov = oview;
 652   for (typename Relocs::const_iterator p = this->relocs_.begin();
 653        p != this->relocs_.end();
 654        ++p)
 655     {
 656       p->write(pov);
 657       pov += reloc_size;
 658     }
 659
 660   gold_assert(pov - oview == oview_size);
 661
 662   of->write_output_view(off, oview_size, oview);
 663
 664   // We no longer need the relocation entries.
 665   this->relocs_.clear();
 666 }
 667
 668 // Output_data_got::Got_entry methods.
 669
 670 // Write out the entry.
 671
 672 template<int size, bool big_endian>
 673 void
 674 Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
 675 {
 676   Valtype val = 0;
 677
 678   switch (this->local_sym_index_)
 679     {
 680     case GSYM_CODE:
 681       {
 682         Symbol* gsym = this->u_.gsym;
 683
 684         // If the symbol is resolved locally, we need to write out its
 685         // value.  Otherwise we just write zero.  The target code is
 686         // responsible for creating a relocation entry to fill in the
 687         // value at runtime. For non-preemptible symbols in a shared
 688         // library, the target will need to record whether or not the
 689         // value should be written (e.g., it may use a RELATIVE
 690         // relocation type).
 691         if (gsym->final_value_is_known() || gsym->needs_value_in_got())
 692           {
 693             Sized_symbol<size>* sgsym;
 694             // This cast is a bit ugly.  We don't want to put a
 695             // virtual method in Symbol, because we want Symbol to be
 696             // as small as possible.
 697             sgsym = static_cast<Sized_symbol<size>*>(gsym);
 698             val = sgsym->value();
 699           }
 700       }
 701       break;
 702
 703     case CONSTANT_CODE:
 704       val = this->u_.constant;
 705       break;
 706
 707     default:
 708       val = this->u_.object->local_symbol_value(this->local_sym_index_);
 709       break;
 710     }
 711
 712   elfcpp::Swap<size, big_endian>::writeval(pov, val);
 713 }
 714
 715 // Output_data_got methods.
 716
 717 // Add an entry for a global symbol to the GOT.  This returns true if
 718 // this is a new GOT entry, false if the symbol already had a GOT
 719 // entry.
 720
 721 template<int size, bool big_endian>
 722 bool
 723 Output_data_got<size, big_endian>::add_global(Symbol* gsym)
 724 {
 725   if (gsym->has_got_offset())
 726     return false;
 727
 728   this->entries_.push_back(Got_entry(gsym));
 729   this->set_got_size();
 730   gsym->set_got_offset(this->last_got_offset());
 731   return true;
 732 }
 733
 734 // Add an entry for a local symbol to the GOT.  This returns true if
 735 // this is a new GOT entry, false if the symbol already has a GOT
 736 // entry.
 737
 738 template<int size, bool big_endian>
 739 bool
 740 Output_data_got<size, big_endian>::add_local(
 741     Sized_relobj<size, big_endian>* object,
 742     unsigned int symndx)
 743 {
 744   if (object->local_has_got_offset(symndx))
 745     return false;
 746
 747   this->entries_.push_back(Got_entry(object, symndx));
 748   this->set_got_size();
 749   object->set_local_got_offset(symndx, this->last_got_offset());
 750   return true;
 751 }
 752
 753 // Add an entry (or a pair of entries) for a global TLS symbol to the GOT.
 754 // In a pair of entries, the first value in the pair will be used for the
 755 // module index, and the second value will be used for the dtv-relative
 756 // offset. This returns true if this is a new GOT entry, false if the symbol
 757 // already has a GOT entry.
 758
 759 template<int size, bool big_endian>
 760 bool
 761 Output_data_got<size, big_endian>::add_global_tls(Symbol* gsym,
 762                                                   bool need_pair)
 763 {
 764   if (gsym->has_tls_got_offset(need_pair))
 765     return false;
 766
 767   this->entries_.push_back(Got_entry(gsym));
 768   gsym->set_tls_got_offset(this->last_got_offset(), need_pair);
 769   if (need_pair)
 770     this->entries_.push_back(Got_entry(gsym));
 771   this->set_got_size();
 772   return true;
 773 }
 774
 775 // Add an entry (or a pair of entries) for a local TLS symbol to the GOT.
 776 // In a pair of entries, the first value in the pair will be used for the
 777 // module index, and the second value will be used for the dtv-relative
 778 // offset. This returns true if this is a new GOT entry, false if the symbol
 779 // already has a GOT entry.
 780
 781 template<int size, bool big_endian>
 782 bool
 783 Output_data_got<size, big_endian>::add_local_tls(
 784     Sized_relobj<size, big_endian>* object,
 785     unsigned int symndx,
 786     bool need_pair)
 787 {
 788   if (object->local_has_tls_got_offset(symndx, need_pair))
 789     return false;
 790
 791   this->entries_.push_back(Got_entry(object, symndx));
 792   object->set_local_tls_got_offset(symndx, this->last_got_offset(), need_pair);
 793   if (need_pair)
 794     this->entries_.push_back(Got_entry(object, symndx));
 795   this->set_got_size();
 796   return true;
 797 }
 798
 799 // Write out the GOT.
 800
 801 template<int size, bool big_endian>
 802 void
 803 Output_data_got<size, big_endian>::do_write(Output_file* of)
 804 {
 805   const int add = size / 8;
 806
 807   const off_t off = this->offset();
 808   const off_t oview_size = this->data_size();
 809   unsigned char* const oview = of->get_output_view(off, oview_size);
 810
 811   unsigned char* pov = oview;
 812   for (typename Got_entries::const_iterator p = this->entries_.begin();
 813        p != this->entries_.end();
 814        ++p)
 815     {
 816       p->write(pov);
 817       pov += add;
 818     }
 819
 820   gold_assert(pov - oview == oview_size);
 821
 822   of->write_output_view(off, oview_size, oview);
 823
 824   // We no longer need the GOT entries.
 825   this->entries_.clear();
 826 }
 827
 828 // Output_data_dynamic::Dynamic_entry methods.
 829
 830 // Write out the entry.
 831
 832 template<int size, bool big_endian>
 833 void
 834 Output_data_dynamic::Dynamic_entry::write(
 835     unsigned char* pov,
 836     const Stringpool* pool
 837     ACCEPT_SIZE_ENDIAN) const
 838 {
 839   typename elfcpp::Elf_types<size>::Elf_WXword val;
 840   switch (this->classification_)
 841     {
 842     case DYNAMIC_NUMBER:
 843       val = this->u_.val;
 844       break;
 845
 846     case DYNAMIC_SECTION_ADDRESS:
 847       val = this->u_.od->address();
 848       break;
 849
 850     case DYNAMIC_SECTION_SIZE:
 851       val = this->u_.od->data_size();
 852       break;
 853
 854     case DYNAMIC_SYMBOL:
 855       {
 856         const Sized_symbol<size>* s =
 857           static_cast<const Sized_symbol<size>*>(this->u_.sym);
 858         val = s->value();
 859       }
 860       break;
 861
 862     case DYNAMIC_STRING:
 863       val = pool->get_offset(this->u_.str);
 864       break;
 865
 866     default:
 867       gold_unreachable();
 868     }
 869
 870   elfcpp::Dyn_write<size, big_endian> dw(pov);
 871   dw.put_d_tag(this->tag_);
 872   dw.put_d_val(val);
 873 }
 874
 875 // Output_data_dynamic methods.
 876
 877 // Adjust the output section to set the entry size.
 878
 879 void
 880 Output_data_dynamic::do_adjust_output_section(Output_section* os)
 881 {
 882   if (parameters->get_size() == 32)
 883     os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size);
 884   else if (parameters->get_size() == 64)
 885     os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size);
 886   else
 887     gold_unreachable();
 888 }
 889
 890 // Set the final data size.
 891
 892 void
 893 Output_data_dynamic::do_set_address(uint64_t, off_t)
 894 {
 895   // Add the terminating entry.
 896   this->add_constant(elfcpp::DT_NULL, 0);
 897
 898   int dyn_size;
 899   if (parameters->get_size() == 32)
 900     dyn_size = elfcpp::Elf_sizes<32>::dyn_size;
 901   else if (parameters->get_size() == 64)
 902     dyn_size = elfcpp::Elf_sizes<64>::dyn_size;
 903   else
 904     gold_unreachable();
 905   this->set_data_size(this->entries_.size() * dyn_size);
 906 }
 907
 908 // Write out the dynamic entries.
 909
 910 void
 911 Output_data_dynamic::do_write(Output_file* of)
 912 {
 913   if (parameters->get_size() == 32)
 914     {
 915       if (parameters->is_big_endian())
 916         {
 917 #ifdef HAVE_TARGET_32_BIG
 918           this->sized_write<32, true>(of);
 919 #else
 920           gold_unreachable();
 921 #endif
 922         }
 923       else
 924         {
 925 #ifdef HAVE_TARGET_32_LITTLE
 926           this->sized_write<32, false>(of);
 927 #else
 928           gold_unreachable();
 929 #endif
 930         }
 931     }
 932   else if (parameters->get_size() == 64)
 933     {
 934       if (parameters->is_big_endian())
 935         {
 936 #ifdef HAVE_TARGET_64_BIG
 937           this->sized_write<64, true>(of);
 938 #else
 939           gold_unreachable();
 940 #endif
 941         }
 942       else
 943         {
 944 #ifdef HAVE_TARGET_64_LITTLE
 945           this->sized_write<64, false>(of);
 946 #else
 947           gold_unreachable();
 948 #endif
 949         }
 950     }
 951   else
 952     gold_unreachable();
 953 }
 954
 955 template<int size, bool big_endian>
 956 void
 957 Output_data_dynamic::sized_write(Output_file* of)
 958 {
 959   const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
 960
 961   const off_t offset = this->offset();
 962   const off_t oview_size = this->data_size();
 963   unsigned char* const oview = of->get_output_view(offset, oview_size);
 964
 965   unsigned char* pov = oview;
 966   for (typename Dynamic_entries::const_iterator p = this->entries_.begin();
 967        p != this->entries_.end();
 968        ++p)
 969     {
 970       p->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
 971           pov, this->pool_ SELECT_SIZE_ENDIAN(size, big_endian));
 972       pov += dyn_size;
 973     }
 974
 975   gold_assert(pov - oview == oview_size);
 976
 977   of->write_output_view(offset, oview_size, oview);
 978
 979   // We no longer need the dynamic entries.
 980   this->entries_.clear();
 981 }
 982
 983 // Output_section::Input_section methods.
 984
 985 // Return the data size.  For an input section we store the size here.
 986 // For an Output_section_data, we have to ask it for the size.
 987
 988 off_t
 989 Output_section::Input_section::data_size() const
 990 {
 991   if (this->is_input_section())
 992     return this->u1_.data_size;
 993   else
 994     return this->u2_.posd->data_size();
 995 }
 996
 997 // Set the address and file offset.
 998
 999 void
1000 Output_section::Input_section::set_address(uint64_t addr, off_t off,
1001                                            off_t secoff)
1002 {
1003   if (this->is_input_section())
1004     this->u2_.object->set_section_offset(this->shndx_, off - secoff);
1005   else
1006     this->u2_.posd->set_address(addr, off);
1007 }
1008
1009 // Try to turn an input offset into an output offset.
1010
1011 bool
1012 Output_section::Input_section::output_offset(const Relobj* object,
1013                                              unsigned int shndx,
1014                                              off_t offset,
1015                                              off_t *poutput) const
1016 {
1017   if (!this->is_input_section())
1018     return this->u2_.posd->output_offset(object, shndx, offset, poutput);
1019   else
1020     {
1021       if (this->shndx_ != shndx || this->u2_.object != object)
1022         return false;
1023       off_t output_offset;
1024       Output_section* os = object->output_section(shndx, &output_offset);
1025       gold_assert(os != NULL);
1026       gold_assert(output_offset != -1);
1027       *poutput = output_offset + offset;
1028       return true;
1029     }
1030 }
1031
1032 // Write out the data.  We don't have to do anything for an input
1033 // section--they are handled via Object::relocate--but this is where
1034 // we write out the data for an Output_section_data.
1035
1036 void
1037 Output_section::Input_section::write(Output_file* of)
1038 {
1039   if (!this->is_input_section())
1040     this->u2_.posd->write(of);
1041 }
1042
1043 // Output_section methods.
1044
1045 // Construct an Output_section.  NAME will point into a Stringpool.
1046
1047 Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
1048                                elfcpp::Elf_Xword flags)
1049   : name_(name),
1050     addralign_(0),
1051     entsize_(0),
1052     link_section_(NULL),
1053     link_(0),
1054     info_section_(NULL),
1055     info_(0),
1056     type_(type),
1057     flags_(flags),
1058     out_shndx_(-1U),
1059     symtab_index_(0),
1060     dynsym_index_(0),
1061     input_sections_(),
1062     first_input_offset_(0),
1063     fills_(),
1064     needs_symtab_index_(false),
1065     needs_dynsym_index_(false),
1066     should_link_to_symtab_(false),
1067     should_link_to_dynsym_(false),
1068     after_input_sections_(false)
1069 {
1070 }
1071
1072 Output_section::~Output_section()
1073 {
1074 }
1075
1076 // Set the entry size.
1077
1078 void
1079 Output_section::set_entsize(uint64_t v)
1080 {
1081   if (this->entsize_ == 0)
1082     this->entsize_ = v;
1083   else
1084     gold_assert(this->entsize_ == v);
1085 }
1086
1087 // Add the input section SHNDX, with header SHDR, named SECNAME, in
1088 // OBJECT, to the Output_section.  RELOC_SHNDX is the index of a
1089 // relocation section which applies to this section, or 0 if none, or
1090 // -1U if more than one.  Return the offset of the input section
1091 // within the output section.  Return -1 if the input section will
1092 // receive special handling.  In the normal case we don't always keep
1093 // track of input sections for an Output_section.  Instead, each
1094 // Object keeps track of the Output_section for each of its input
1095 // sections.
1096
1097 template<int size, bool big_endian>
1098 off_t
1099 Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
1100                                   unsigned int shndx,
1101                                   const char* secname,
1102                                   const elfcpp::Shdr<size, big_endian>& shdr,
1103                                   unsigned int reloc_shndx)
1104 {
1105   elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
1106   if ((addralign & (addralign - 1)) != 0)
1107     {
1108       object->error(_("invalid alignment %lu for section \"%s\""),
1109                     static_cast<unsigned long>(addralign), secname);
1110       addralign = 1;
1111     }
1112
1113   if (addralign > this->addralign_)
1114     this->addralign_ = addralign;
1115
1116   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1117
1118   // .debug_str is a mergeable string section, but is not always so
1119   // marked by compilers.  Mark manually here so we can optimize.
1120   if (strcmp(secname, ".debug_str") == 0)
1121     sh_flags |= (elfcpp::SHF_MERGE | elfcpp::SHF_STRINGS);
1122
1123   // If this is a SHF_MERGE section, we pass all the input sections to
1124   // a Output_data_merge.  We don't try to handle relocations for such
1125   // a section.
1126   if ((sh_flags & elfcpp::SHF_MERGE) != 0
1127       && reloc_shndx == 0)
1128     {
1129       if (this->add_merge_input_section(object, shndx, sh_flags,
1130                                         shdr.get_sh_entsize(),
1131                                         addralign))
1132         {
1133           // Tell the relocation routines that they need to call the
1134           // output_offset method to determine the final address.
1135           return -1;
1136         }
1137     }
1138
1139   off_t offset_in_section = this->data_size();
1140   off_t aligned_offset_in_section = align_address(offset_in_section,
1141                                                   addralign);
1142
1143   if (aligned_offset_in_section > offset_in_section
1144       && (sh_flags & elfcpp::SHF_EXECINSTR) != 0
1145       && object->target()->has_code_fill())
1146     {
1147       // We need to add some fill data.  Using fill_list_ when
1148       // possible is an optimization, since we will often have fill
1149       // sections without input sections.
1150       off_t fill_len = aligned_offset_in_section - offset_in_section;
1151       if (this->input_sections_.empty())
1152         this->fills_.push_back(Fill(offset_in_section, fill_len));
1153       else
1154         {
1155           // FIXME: When relaxing, the size needs to adjust to
1156           // maintain a constant alignment.
1157           std::string fill_data(object->target()->code_fill(fill_len));
1158           Output_data_const* odc = new Output_data_const(fill_data, 1);
1159           this->input_sections_.push_back(Input_section(odc));
1160         }
1161     }
1162
1163   this->set_data_size(aligned_offset_in_section + shdr.get_sh_size());
1164
1165   // We need to keep track of this section if we are already keeping
1166   // track of sections, or if we are relaxing.  FIXME: Add test for
1167   // relaxing.
1168   if (!this->input_sections_.empty())
1169     this->input_sections_.push_back(Input_section(object, shndx,
1170                                                   shdr.get_sh_size(),
1171                                                   addralign));
1172
1173   return aligned_offset_in_section;
1174 }
1175
1176 // Add arbitrary data to an output section.
1177
1178 void
1179 Output_section::add_output_section_data(Output_section_data* posd)
1180 {
1181   Input_section inp(posd);
1182   this->add_output_section_data(&inp);
1183 }
1184
1185 // Add arbitrary data to an output section by Input_section.
1186
1187 void
1188 Output_section::add_output_section_data(Input_section* inp)
1189 {
1190   if (this->input_sections_.empty())
1191     this->first_input_offset_ = this->data_size();
1192
1193   this->input_sections_.push_back(*inp);
1194
1195   uint64_t addralign = inp->addralign();
1196   if (addralign > this->addralign_)
1197     this->addralign_ = addralign;
1198
1199   inp->set_output_section(this);
1200 }
1201
1202 // Add a merge section to an output section.
1203
1204 void
1205 Output_section::add_output_merge_section(Output_section_data* posd,
1206                                          bool is_string, uint64_t entsize)
1207 {
1208   Input_section inp(posd, is_string, entsize);
1209   this->add_output_section_data(&inp);
1210 }
1211
1212 // Add an input section to a SHF_MERGE section.
1213
1214 bool
1215 Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
1216                                         uint64_t flags, uint64_t entsize,
1217                                         uint64_t addralign)
1218 {
1219   bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
1220
1221   // We only merge strings if the alignment is not more than the
1222   // character size.  This could be handled, but it's unusual.
1223   if (is_string && addralign > entsize)
1224     return false;
1225
1226   Input_section_list::iterator p;
1227   for (p = this->input_sections_.begin();
1228        p != this->input_sections_.end();
1229        ++p)
1230     if (p->is_merge_section(is_string, entsize, addralign))
1231       break;
1232
1233   // We handle the actual constant merging in Output_merge_data or
1234   // Output_merge_string_data.
1235   if (p != this->input_sections_.end())
1236     p->add_input_section(object, shndx);
1237   else
1238     {
1239       Output_section_data* posd;
1240       if (!is_string)
1241         posd = new Output_merge_data(entsize, addralign);
1242       else if (entsize == 1)
1243         posd = new Output_merge_string<char>(addralign);
1244       else if (entsize == 2)
1245         posd = new Output_merge_string<uint16_t>(addralign);
1246       else if (entsize == 4)
1247         posd = new Output_merge_string<uint32_t>(addralign);
1248       else
1249         return false;
1250
1251       this->add_output_merge_section(posd, is_string, entsize);
1252       posd->add_input_section(object, shndx);
1253     }
1254
1255   return true;
1256 }
1257
1258 // Given an address OFFSET relative to the start of input section
1259 // SHNDX in OBJECT, return whether this address is being included in
1260 // the final link.  This should only be called if SHNDX in OBJECT has
1261 // a special mapping.
1262
1263 bool
1264 Output_section::is_input_address_mapped(const Relobj* object,
1265                                         unsigned int shndx,
1266                                         off_t offset) const
1267 {
1268   gold_assert(object->is_section_specially_mapped(shndx));
1269
1270   for (Input_section_list::const_iterator p = this->input_sections_.begin();
1271        p != this->input_sections_.end();
1272        ++p)
1273     {
1274       off_t output_offset;
1275       if (p->output_offset(object, shndx, offset, &output_offset))
1276         return output_offset != -1;
1277     }
1278
1279   // By default we assume that the address is mapped.  This should
1280   // only be called after we have passed all sections to Layout.  At
1281   // that point we should know what we are discarding.
1282   return true;
1283 }
1284
1285 // Given an address OFFSET relative to the start of input section
1286 // SHNDX in object OBJECT, return the output offset relative to the
1287 // start of the section.  This should only be called if SHNDX in
1288 // OBJECT has a special mapping.
1289
1290 off_t
1291 Output_section::output_offset(const Relobj* object, unsigned int shndx,
1292                               off_t offset) const
1293 {
1294   gold_assert(object->is_section_specially_mapped(shndx));
1295   // This can only be called meaningfully when layout is complete.
1296   gold_assert(Output_data::is_layout_complete());
1297
1298   for (Input_section_list::const_iterator p = this->input_sections_.begin();
1299        p != this->input_sections_.end();
1300        ++p)
1301     {
1302       off_t output_offset;
1303       if (p->output_offset(object, shndx, offset, &output_offset))
1304         return output_offset;
1305     }
1306   gold_unreachable();
1307 }
1308
1309 // Return the output virtual address of OFFSET relative to the start
1310 // of input section SHNDX in object OBJECT.
1311
1312 uint64_t
1313 Output_section::output_address(const Relobj* object, unsigned int shndx,
1314                                off_t offset) const
1315 {
1316   gold_assert(object->is_section_specially_mapped(shndx));
1317   // This can only be called meaningfully when layout is complete.
1318   gold_assert(Output_data::is_layout_complete());
1319
1320   uint64_t addr = this->address() + this->first_input_offset_;
1321   for (Input_section_list::const_iterator p = this->input_sections_.begin();
1322        p != this->input_sections_.end();
1323        ++p)
1324     {
1325       addr = align_address(addr, p->addralign());
1326       off_t output_offset;
1327       if (p->output_offset(object, shndx, offset, &output_offset))
1328         {
1329           if (output_offset == -1)
1330             return -1U;
1331           return addr + output_offset;
1332         }
1333       addr += p->data_size();
1334     }
1335
1336   // If we get here, it means that we don't know the mapping for this
1337   // input section.  This might happen in principle if
1338   // add_input_section were called before add_output_section_data.
1339   // But it should never actually happen.
1340
1341   gold_unreachable();
1342 }
1343
1344 // Set the address of an Output_section.  This is where we handle
1345 // setting the addresses of any Output_section_data objects.
1346
1347 void
1348 Output_section::do_set_address(uint64_t address, off_t startoff)
1349 {
1350   if (this->input_sections_.empty())
1351     return;
1352
1353   off_t off = startoff + this->first_input_offset_;
1354   for (Input_section_list::iterator p = this->input_sections_.begin();
1355        p != this->input_sections_.end();
1356        ++p)
1357     {
1358       off = align_address(off, p->addralign());
1359       p->set_address(address + (off - startoff), off, startoff);
1360       off += p->data_size();
1361     }
1362
1363   this->set_data_size(off - startoff);
1364 }
1365
1366 // Write the section header to *OSHDR.
1367
1368 template<int size, bool big_endian>
1369 void
1370 Output_section::write_header(const Layout* layout,
1371                              const Stringpool* secnamepool,
1372                              elfcpp::Shdr_write<size, big_endian>* oshdr) const
1373 {
1374   oshdr->put_sh_name(secnamepool->get_offset(this->name_));
1375   oshdr->put_sh_type(this->type_);
1376   oshdr->put_sh_flags(this->flags_);
1377   oshdr->put_sh_addr(this->address());
1378   oshdr->put_sh_offset(this->offset());
1379   oshdr->put_sh_size(this->data_size());
1380   if (this->link_section_ != NULL)
1381     oshdr->put_sh_link(this->link_section_->out_shndx());
1382   else if (this->should_link_to_symtab_)
1383     oshdr->put_sh_link(layout->symtab_section()->out_shndx());
1384   else if (this->should_link_to_dynsym_)
1385     oshdr->put_sh_link(layout->dynsym_section()->out_shndx());
1386   else
1387     oshdr->put_sh_link(this->link_);
1388   if (this->info_section_ != NULL)
1389     oshdr->put_sh_info(this->info_section_->out_shndx());
1390   else
1391     oshdr->put_sh_info(this->info_);
1392   oshdr->put_sh_addralign(this->addralign_);
1393   oshdr->put_sh_entsize(this->entsize_);
1394 }
1395
1396 // Write out the data.  For input sections the data is written out by
1397 // Object::relocate, but we have to handle Output_section_data objects
1398 // here.
1399
1400 void
1401 Output_section::do_write(Output_file* of)
1402 {
1403   off_t output_section_file_offset = this->offset();
1404   for (Fill_list::iterator p = this->fills_.begin();
1405        p != this->fills_.end();
1406        ++p)
1407     {
1408       std::string fill_data(of->target()->code_fill(p->length()));
1409       of->write(output_section_file_offset + p->section_offset(),
1410                 fill_data.data(), fill_data.size());
1411     }
1412
1413   for (Input_section_list::iterator p = this->input_sections_.begin();
1414        p != this->input_sections_.end();
1415        ++p)
1416     p->write(of);
1417 }
1418
1419 // Output segment methods.
1420
1421 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
1422   : output_data_(),
1423     output_bss_(),
1424     vaddr_(0),
1425     paddr_(0),
1426     memsz_(0),
1427     align_(0),
1428     offset_(0),
1429     filesz_(0),
1430     type_(type),
1431     flags_(flags),
1432     is_align_known_(false)
1433 {
1434 }
1435
1436 // Add an Output_section to an Output_segment.
1437
1438 void
1439 Output_segment::add_output_section(Output_section* os,
1440                                    elfcpp::Elf_Word seg_flags,
1441                                    bool front)
1442 {
1443   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1444   gold_assert(!this->is_align_known_);
1445
1446   // Update the segment flags.
1447   this->flags_ |= seg_flags;
1448
1449   Output_segment::Output_data_list* pdl;
1450   if (os->type() == elfcpp::SHT_NOBITS)
1451     pdl = &this->output_bss_;
1452   else
1453     pdl = &this->output_data_;
1454
1455   // So that PT_NOTE segments will work correctly, we need to ensure
1456   // that all SHT_NOTE sections are adjacent.  This will normally
1457   // happen automatically, because all the SHT_NOTE input sections
1458   // will wind up in the same output section.  However, it is possible
1459   // for multiple SHT_NOTE input sections to have different section
1460   // flags, and thus be in different output sections, but for the
1461   // different section flags to map into the same segment flags and
1462   // thus the same output segment.
1463
1464   // Note that while there may be many input sections in an output
1465   // section, there are normally only a few output sections in an
1466   // output segment.  This loop is expected to be fast.
1467
1468   if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
1469     {
1470       Output_segment::Output_data_list::iterator p = pdl->end();
1471       do
1472         {
1473           --p;
1474           if ((*p)->is_section_type(elfcpp::SHT_NOTE))
1475             {
1476               // We don't worry about the FRONT parameter.
1477               ++p;
1478               pdl->insert(p, os);
1479               return;
1480             }
1481         }
1482       while (p != pdl->begin());
1483     }
1484
1485   // Similarly, so that PT_TLS segments will work, we need to group
1486   // SHF_TLS sections.  An SHF_TLS/SHT_NOBITS section is a special
1487   // case: we group the SHF_TLS/SHT_NOBITS sections right after the
1488   // SHF_TLS/SHT_PROGBITS sections.  This lets us set up PT_TLS
1489   // correctly.  SHF_TLS sections get added to both a PT_LOAD segment
1490   // and the PT_TLS segment -- we do this grouping only for the
1491   // PT_LOAD segment.
1492   if (this->type_ != elfcpp::PT_TLS
1493       && (os->flags() & elfcpp::SHF_TLS) != 0
1494       && !this->output_data_.empty())
1495     {
1496       pdl = &this->output_data_;
1497       bool nobits = os->type() == elfcpp::SHT_NOBITS;
1498       bool sawtls = false;
1499       Output_segment::Output_data_list::iterator p = pdl->end();
1500       do
1501         {
1502           --p;
1503           bool insert;
1504           if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
1505             {
1506               sawtls = true;
1507               // Put a NOBITS section after the first TLS section.
1508               // But a PROGBITS section after the first TLS/PROGBITS
1509               // section.
1510               insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
1511             }
1512           else
1513             {
1514               // If we've gone past the TLS sections, but we've seen a
1515               // TLS section, then we need to insert this section now.
1516               insert = sawtls;
1517             }
1518
1519           if (insert)
1520             {
1521               // We don't worry about the FRONT parameter.
1522               ++p;
1523               pdl->insert(p, os);
1524               return;
1525             }
1526         }
1527       while (p != pdl->begin());
1528
1529       // There are no TLS sections yet; put this one at the requested
1530       // location in the section list.
1531     }
1532
1533   if (front)
1534     pdl->push_front(os);
1535   else
1536     pdl->push_back(os);
1537 }
1538
1539 // Add an Output_data (which is not an Output_section) to the start of
1540 // a segment.
1541
1542 void
1543 Output_segment::add_initial_output_data(Output_data* od)
1544 {
1545   gold_assert(!this->is_align_known_);
1546   this->output_data_.push_front(od);
1547 }
1548
1549 // Return the maximum alignment of the Output_data in Output_segment.
1550 // Once we compute this, we prohibit new sections from being added.
1551
1552 uint64_t
1553 Output_segment::addralign()
1554 {
1555   if (!this->is_align_known_)
1556     {
1557       uint64_t addralign;
1558
1559       addralign = Output_segment::maximum_alignment(&this->output_data_);
1560       if (addralign > this->align_)
1561         this->align_ = addralign;
1562
1563       addralign = Output_segment::maximum_alignment(&this->output_bss_);
1564       if (addralign > this->align_)
1565         this->align_ = addralign;
1566
1567       this->is_align_known_ = true;
1568     }
1569
1570   return this->align_;
1571 }
1572
1573 // Return the maximum alignment of a list of Output_data.
1574
1575 uint64_t
1576 Output_segment::maximum_alignment(const Output_data_list* pdl)
1577 {
1578   uint64_t ret = 0;
1579   for (Output_data_list::const_iterator p = pdl->begin();
1580        p != pdl->end();
1581        ++p)
1582     {
1583       uint64_t addralign = (*p)->addralign();
1584       if (addralign > ret)
1585         ret = addralign;
1586     }
1587   return ret;
1588 }
1589
1590 // Return the number of dynamic relocs applied to this segment.
1591
1592 unsigned int
1593 Output_segment::dynamic_reloc_count() const
1594 {
1595   return (this->dynamic_reloc_count_list(&this->output_data_)
1596           + this->dynamic_reloc_count_list(&this->output_bss_));
1597 }
1598
1599 // Return the number of dynamic relocs applied to an Output_data_list.
1600
1601 unsigned int
1602 Output_segment::dynamic_reloc_count_list(const Output_data_list* pdl) const
1603 {
1604   unsigned int count = 0;
1605   for (Output_data_list::const_iterator p = pdl->begin();
1606        p != pdl->end();
1607        ++p)
1608     count += (*p)->dynamic_reloc_count();
1609   return count;
1610 }
1611
1612 // Set the section addresses for an Output_segment.  ADDR is the
1613 // address and *POFF is the file offset.  Set the section indexes
1614 // starting with *PSHNDX.  Return the address of the immediately
1615 // following segment.  Update *POFF and *PSHNDX.
1616
1617 uint64_t
1618 Output_segment::set_section_addresses(uint64_t addr, off_t* poff,
1619                                       unsigned int* pshndx)
1620 {
1621   gold_assert(this->type_ == elfcpp::PT_LOAD);
1622
1623   this->vaddr_ = addr;
1624   this->paddr_ = addr;
1625
1626   off_t orig_off = *poff;
1627   this->offset_ = orig_off;
1628
1629   *poff = align_address(*poff, this->addralign());
1630
1631   addr = this->set_section_list_addresses(&this->output_data_, addr, poff,
1632                                           pshndx);
1633   this->filesz_ = *poff - orig_off;
1634
1635   off_t off = *poff;
1636
1637   uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr,
1638                                                   poff, pshndx);
1639   this->memsz_ = *poff - orig_off;
1640
1641   // Ignore the file offset adjustments made by the BSS Output_data
1642   // objects.
1643   *poff = off;
1644
1645   return ret;
1646 }
1647
1648 // Set the addresses and file offsets in a list of Output_data
1649 // structures.
1650
1651 uint64_t
1652 Output_segment::set_section_list_addresses(Output_data_list* pdl,
1653                                            uint64_t addr, off_t* poff,
1654                                            unsigned int* pshndx)
1655 {
1656   off_t startoff = *poff;
1657
1658   off_t off = startoff;
1659   for (Output_data_list::iterator p = pdl->begin();
1660        p != pdl->end();
1661        ++p)
1662     {
1663       off = align_address(off, (*p)->addralign());
1664       (*p)->set_address(addr + (off - startoff), off);
1665
1666       // Unless this is a PT_TLS segment, we want to ignore the size
1667       // of a SHF_TLS/SHT_NOBITS section.  Such a section does not
1668       // affect the size of a PT_LOAD segment.
1669       if (this->type_ == elfcpp::PT_TLS
1670           || !(*p)->is_section_flag_set(elfcpp::SHF_TLS)
1671           || !(*p)->is_section_type(elfcpp::SHT_NOBITS))
1672         off += (*p)->data_size();
1673
1674       if ((*p)->is_section())
1675         {
1676           (*p)->set_out_shndx(*pshndx);
1677           ++*pshndx;
1678         }
1679     }
1680
1681   *poff = off;
1682   return addr + (off - startoff);
1683 }
1684
1685 // For a non-PT_LOAD segment, set the offset from the sections, if
1686 // any.
1687
1688 void
1689 Output_segment::set_offset()
1690 {
1691   gold_assert(this->type_ != elfcpp::PT_LOAD);
1692
1693   if (this->output_data_.empty() && this->output_bss_.empty())
1694     {
1695       this->vaddr_ = 0;
1696       this->paddr_ = 0;
1697       this->memsz_ = 0;
1698       this->align_ = 0;
1699       this->offset_ = 0;
1700       this->filesz_ = 0;
1701       return;
1702     }
1703
1704   const Output_data* first;
1705   if (this->output_data_.empty())
1706     first = this->output_bss_.front();
1707   else
1708     first = this->output_data_.front();
1709   this->vaddr_ = first->address();
1710   this->paddr_ = this->vaddr_;
1711   this->offset_ = first->offset();
1712
1713   if (this->output_data_.empty())
1714     this->filesz_ = 0;
1715   else
1716     {
1717       const Output_data* last_data = this->output_data_.back();
1718       this->filesz_ = (last_data->address()
1719                        + last_data->data_size()
1720                        - this->vaddr_);
1721     }
1722
1723   const Output_data* last;
1724   if (this->output_bss_.empty())
1725     last = this->output_data_.back();
1726   else
1727     last = this->output_bss_.back();
1728   this->memsz_ = (last->address()
1729                   + last->data_size()
1730                   - this->vaddr_);
1731 }
1732
1733 // Return the number of Output_sections in an Output_segment.
1734
1735 unsigned int
1736 Output_segment::output_section_count() const
1737 {
1738   return (this->output_section_count_list(&this->output_data_)
1739           + this->output_section_count_list(&this->output_bss_));
1740 }
1741
1742 // Return the number of Output_sections in an Output_data_list.
1743
1744 unsigned int
1745 Output_segment::output_section_count_list(const Output_data_list* pdl) const
1746 {
1747   unsigned int count = 0;
1748   for (Output_data_list::const_iterator p = pdl->begin();
1749        p != pdl->end();
1750        ++p)
1751     {
1752       if ((*p)->is_section())
1753         ++count;
1754     }
1755   return count;
1756 }
1757
1758 // Write the segment data into *OPHDR.
1759
1760 template<int size, bool big_endian>
1761 void
1762 Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr)
1763 {
1764   ophdr->put_p_type(this->type_);
1765   ophdr->put_p_offset(this->offset_);
1766   ophdr->put_p_vaddr(this->vaddr_);
1767   ophdr->put_p_paddr(this->paddr_);
1768   ophdr->put_p_filesz(this->filesz_);
1769   ophdr->put_p_memsz(this->memsz_);
1770   ophdr->put_p_flags(this->flags_);
1771   ophdr->put_p_align(this->addralign());
1772 }
1773
1774 // Write the section headers into V.
1775
1776 template<int size, bool big_endian>
1777 unsigned char*
1778 Output_segment::write_section_headers(const Layout* layout,
1779                                       const Stringpool* secnamepool,
1780                                       unsigned char* v,
1781                                       unsigned int *pshndx
1782                                       ACCEPT_SIZE_ENDIAN) const
1783 {
1784   // Every section that is attached to a segment must be attached to a
1785   // PT_LOAD segment, so we only write out section headers for PT_LOAD
1786   // segments.
1787   if (this->type_ != elfcpp::PT_LOAD)
1788     return v;
1789
1790   v = this->write_section_headers_list
1791       SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1792           layout, secnamepool, &this->output_data_, v, pshndx
1793           SELECT_SIZE_ENDIAN(size, big_endian));
1794   v = this->write_section_headers_list
1795       SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1796           layout, secnamepool, &this->output_bss_, v, pshndx
1797           SELECT_SIZE_ENDIAN(size, big_endian));
1798   return v;
1799 }
1800
1801 template<int size, bool big_endian>
1802 unsigned char*
1803 Output_segment::write_section_headers_list(const Layout* layout,
1804                                            const Stringpool* secnamepool,
1805                                            const Output_data_list* pdl,
1806                                            unsigned char* v,
1807                                            unsigned int* pshndx
1808                                            ACCEPT_SIZE_ENDIAN) const
1809 {
1810   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
1811   for (Output_data_list::const_iterator p = pdl->begin();
1812        p != pdl->end();
1813        ++p)
1814     {
1815       if ((*p)->is_section())
1816         {
1817           const Output_section* ps = static_cast<const Output_section*>(*p);
1818           gold_assert(*pshndx == ps->out_shndx());
1819           elfcpp::Shdr_write<size, big_endian> oshdr(v);
1820           ps->write_header(layout, secnamepool, &oshdr);
1821           v += shdr_size;
1822           ++*pshndx;
1823         }
1824     }
1825   return v;
1826 }
1827
1828 // Output_file methods.
1829
1830 Output_file::Output_file(const General_options& options, Target* target)
1831   : options_(options),
1832     target_(target),
1833     name_(options.output_file_name()),
1834     o_(-1),
1835     file_size_(0),
1836     base_(NULL)
1837 {
1838 }
1839
1840 // Open the output file.
1841
1842 void
1843 Output_file::open(off_t file_size)
1844 {
1845   this->file_size_ = file_size;
1846
1847   // Unlink the file first; otherwise the open() may fail if the file
1848   // is busy (e.g. it's an executable that's currently being executed).
1849   //
1850   // However, the linker may be part of a system where a zero-length
1851   // file is created for it to write to, with tight permissions (gcc
1852   // 2.95 did something like this).  Unlinking the file would work
1853   // around those permission controls, so we only unlink if the file
1854   // has a non-zero size.  We also unlink only regular files to avoid
1855   // trouble with directories/etc.
1856   //
1857   // If we fail, continue; this command is merely a best-effort attempt
1858   // to improve the odds for open().
1859
1860   struct stat s;
1861   if (::stat(this->name_, &s) == 0 && s.st_size != 0)
1862     unlink_if_ordinary(this->name_);
1863
1864   int mode = parameters->output_is_object() ? 0666 : 0777;
1865   int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode);
1866   if (o < 0)
1867     gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
1868   this->o_ = o;
1869
1870   // Write out one byte to make the file the right size.
1871   if (::lseek(o, file_size - 1, SEEK_SET) < 0)
1872     gold_fatal(_("%s: lseek: %s"), this->name_, strerror(errno));
1873   char b = 0;
1874   if (::write(o, &b, 1) != 1)
1875     gold_fatal(_("%s: write: %s"), this->name_, strerror(errno));
1876
1877   // Map the file into memory.
1878   void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE,
1879                       MAP_SHARED, o, 0);
1880   if (base == MAP_FAILED)
1881     gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
1882   this->base_ = static_cast<unsigned char*>(base);
1883 }
1884
1885 // Close the output file.
1886
1887 void
1888 Output_file::close()
1889 {
1890   if (::munmap(this->base_, this->file_size_) < 0)
1891     gold_error(_("%s: munmap: %s"), this->name_, strerror(errno));
1892   this->base_ = NULL;
1893
1894   if (::close(this->o_) < 0)
1895     gold_error(_("%s: close: %s"), this->name_, strerror(errno));
1896   this->o_ = -1;
1897 }
1898
1899 // Instantiate the templates we need.  We could use the configure
1900 // script to restrict this to only the ones for implemented targets.
1901
1902 #ifdef HAVE_TARGET_32_LITTLE
1903 template
1904 off_t
1905 Output_section::add_input_section<32, false>(
1906     Sized_relobj<32, false>* object,
1907     unsigned int shndx,
1908     const char* secname,
1909     const elfcpp::Shdr<32, false>& shdr,
1910     unsigned int reloc_shndx);
1911 #endif
1912
1913 #ifdef HAVE_TARGET_32_BIG
1914 template
1915 off_t
1916 Output_section::add_input_section<32, true>(
1917     Sized_relobj<32, true>* object,
1918     unsigned int shndx,
1919     const char* secname,
1920     const elfcpp::Shdr<32, true>& shdr,
1921     unsigned int reloc_shndx);
1922 #endif
1923
1924 #ifdef HAVE_TARGET_64_LITTLE
1925 template
1926 off_t
1927 Output_section::add_input_section<64, false>(
1928     Sized_relobj<64, false>* object,
1929     unsigned int shndx,
1930     const char* secname,
1931     const elfcpp::Shdr<64, false>& shdr,
1932     unsigned int reloc_shndx);
1933 #endif
1934
1935 #ifdef HAVE_TARGET_64_BIG
1936 template
1937 off_t
1938 Output_section::add_input_section<64, true>(
1939     Sized_relobj<64, true>* object,
1940     unsigned int shndx,
1941     const char* secname,
1942     const elfcpp::Shdr<64, true>& shdr,
1943     unsigned int reloc_shndx);
1944 #endif
1945
1946 #ifdef HAVE_TARGET_32_LITTLE
1947 template
1948 class Output_data_reloc<elfcpp::SHT_REL, false, 32, false>;
1949 #endif
1950
1951 #ifdef HAVE_TARGET_32_BIG
1952 template
1953 class Output_data_reloc<elfcpp::SHT_REL, false, 32, true>;
1954 #endif
1955
1956 #ifdef HAVE_TARGET_64_LITTLE
1957 template
1958 class Output_data_reloc<elfcpp::SHT_REL, false, 64, false>;
1959 #endif
1960
1961 #ifdef HAVE_TARGET_64_BIG
1962 template
1963 class Output_data_reloc<elfcpp::SHT_REL, false, 64, true>;
1964 #endif
1965
1966 #ifdef HAVE_TARGET_32_LITTLE
1967 template
1968 class Output_data_reloc<elfcpp::SHT_REL, true, 32, false>;
1969 #endif
1970
1971 #ifdef HAVE_TARGET_32_BIG
1972 template
1973 class Output_data_reloc<elfcpp::SHT_REL, true, 32, true>;
1974 #endif
1975
1976 #ifdef HAVE_TARGET_64_LITTLE
1977 template
1978 class Output_data_reloc<elfcpp::SHT_REL, true, 64, false>;
1979 #endif
1980
1981 #ifdef HAVE_TARGET_64_BIG
1982 template
1983 class Output_data_reloc<elfcpp::SHT_REL, true, 64, true>;
1984 #endif
1985
1986 #ifdef HAVE_TARGET_32_LITTLE
1987 template
1988 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, false>;
1989 #endif
1990
1991 #ifdef HAVE_TARGET_32_BIG
1992 template
1993 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, true>;
1994 #endif
1995
1996 #ifdef HAVE_TARGET_64_LITTLE
1997 template
1998 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, false>;
1999 #endif
2000
2001 #ifdef HAVE_TARGET_64_BIG
2002 template
2003 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, true>;
2004 #endif
2005
2006 #ifdef HAVE_TARGET_32_LITTLE
2007 template
2008 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, false>;
2009 #endif
2010
2011 #ifdef HAVE_TARGET_32_BIG
2012 template
2013 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, true>;
2014 #endif
2015
2016 #ifdef HAVE_TARGET_64_LITTLE
2017 template
2018 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, false>;
2019 #endif
2020
2021 #ifdef HAVE_TARGET_64_BIG
2022 template
2023 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, true>;
2024 #endif
2025
2026 #ifdef HAVE_TARGET_32_LITTLE
2027 template
2028 class Output_data_got<32, false>;
2029 #endif
2030
2031 #ifdef HAVE_TARGET_32_BIG
2032 template
2033 class Output_data_got<32, true>;
2034 #endif
2035
2036 #ifdef HAVE_TARGET_64_LITTLE
2037 template
2038 class Output_data_got<64, false>;
2039 #endif
2040
2041 #ifdef HAVE_TARGET_64_BIG
2042 template
2043 class Output_data_got<64, true>;
2044 #endif
2045
2046 } // End namespace gold.