gold/output.cc

   1 // output.cc -- manage the output file for gold
   2
   3 #include "gold.h"
   4
   5 #include <cstdlib>
   6 #include <cerrno>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include <sys/mman.h>
  10 #include <algorithm>
  11
  12 #include "object.h"
  13 #include "symtab.h"
  14 #include "reloc.h"
  15 #include "output.h"
  16
  17 namespace gold
  18 {
  19
  20 // Output_data methods.
  21
  22 Output_data::~Output_data()
  23 {
  24 }
  25
  26 // Set the address and offset.
  27
  28 void
  29 Output_data::set_address(uint64_t addr, off_t off)
  30 {
  31   this->address_ = addr;
  32   this->offset_ = off;
  33
  34   // Let the child class know.
  35   this->do_set_address(addr, off);
  36 }
  37
  38 // Return the default alignment for a size--32 or 64.
  39
  40 uint64_t
  41 Output_data::default_alignment(int size)
  42 {
  43   if (size == 32)
  44     return 4;
  45   else if (size == 64)
  46     return 8;
  47   else
  48     abort();
  49 }
  50
  51 // Output_data_const methods.
  52
  53 void
  54 Output_data_const::do_write(Output_file* output)
  55 {
  56   output->write(this->offset(), data_.data(), data_.size());
  57 }
  58
  59 // Output_section_header methods.  This currently assumes that the
  60 // segment and section lists are complete at construction time.
  61
  62 Output_section_headers::Output_section_headers(
  63     int size,
  64     bool big_endian,
  65     const Layout::Segment_list& segment_list,
  66     const Layout::Section_list& section_list,
  67     const Stringpool* secnamepool)
  68   : size_(size),
  69     big_endian_(big_endian),
  70     segment_list_(segment_list),
  71     section_list_(section_list),
  72     secnamepool_(secnamepool)
  73 {
  74   // Count all the sections.  Start with 1 for the null section.
  75   off_t count = 1;
  76   for (Layout::Segment_list::const_iterator p = segment_list.begin();
  77        p != segment_list.end();
  78        ++p)
  79     if ((*p)->type() == elfcpp::PT_LOAD)
  80       count += (*p)->output_section_count();
  81   count += section_list.size();
  82
  83   int shdr_size;
  84   if (size == 32)
  85     shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
  86   else if (size == 64)
  87     shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
  88   else
  89     abort();
  90
  91   this->set_data_size(count * shdr_size);
  92 }
  93
  94 // Write out the section headers.
  95
  96 void
  97 Output_section_headers::do_write(Output_file* of)
  98 {
  99   if (this->size_ == 32)
 100     {
 101       if (this->big_endian_)
 102         this->do_sized_write<32, true>(of);
 103       else
 104         this->do_sized_write<32, false>(of);
 105     }
 106   else if (this->size_ == 64)
 107     {
 108       if (this->big_endian_)
 109         this->do_sized_write<64, true>(of);
 110       else
 111         this->do_sized_write<64, false>(of);
 112     }
 113   else
 114     abort();
 115 }
 116
 117 template<int size, bool big_endian>
 118 void
 119 Output_section_headers::do_sized_write(Output_file* of)
 120 {
 121   off_t all_shdrs_size = this->data_size();
 122   unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
 123
 124   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 125   unsigned char* v = view;
 126
 127   {
 128     typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
 129     oshdr.put_sh_name(0);
 130     oshdr.put_sh_type(elfcpp::SHT_NULL);
 131     oshdr.put_sh_flags(0);
 132     oshdr.put_sh_addr(0);
 133     oshdr.put_sh_offset(0);
 134     oshdr.put_sh_size(0);
 135     oshdr.put_sh_link(0);
 136     oshdr.put_sh_info(0);
 137     oshdr.put_sh_addralign(0);
 138     oshdr.put_sh_entsize(0);
 139   }
 140
 141   v += shdr_size;
 142
 143   unsigned shndx = 1;
 144   for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
 145        p != this->segment_list_.end();
 146        ++p)
 147     v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME (
 148             this->secnamepool_, v, &shndx
 149             SELECT_SIZE_ENDIAN(size, big_endian));
 150   for (Layout::Section_list::const_iterator p = this->section_list_.begin();
 151        p != this->section_list_.end();
 152        ++p)
 153     {
 154       assert(shndx == (*p)->out_shndx());
 155       elfcpp::Shdr_write<size, big_endian> oshdr(v);
 156       (*p)->write_header(this->secnamepool_, &oshdr);
 157       v += shdr_size;
 158       ++shndx;
 159     }
 160
 161   of->write_output_view(this->offset(), all_shdrs_size, view);
 162 }
 163
 164 // Output_segment_header methods.
 165
 166 Output_segment_headers::Output_segment_headers(
 167     int size,
 168     bool big_endian,
 169     const Layout::Segment_list& segment_list)
 170   : size_(size), big_endian_(big_endian), segment_list_(segment_list)
 171 {
 172   int phdr_size;
 173   if (size == 32)
 174     phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
 175   else if (size == 64)
 176     phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
 177   else
 178     abort();
 179
 180   this->set_data_size(segment_list.size() * phdr_size);
 181 }
 182
 183 void
 184 Output_segment_headers::do_write(Output_file* of)
 185 {
 186   if (this->size_ == 32)
 187     {
 188       if (this->big_endian_)
 189         this->do_sized_write<32, true>(of);
 190       else
 191         this->do_sized_write<32, false>(of);
 192     }
 193   else if (this->size_ == 64)
 194     {
 195       if (this->big_endian_)
 196         this->do_sized_write<64, true>(of);
 197       else
 198         this->do_sized_write<64, false>(of);
 199     }
 200   else
 201     abort();
 202 }
 203
 204 template<int size, bool big_endian>
 205 void
 206 Output_segment_headers::do_sized_write(Output_file* of)
 207 {
 208   const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
 209   off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
 210   unsigned char* view = of->get_output_view(this->offset(),
 211                                             all_phdrs_size);
 212   unsigned char* v = view;
 213   for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
 214        p != this->segment_list_.end();
 215        ++p)
 216     {
 217       elfcpp::Phdr_write<size, big_endian> ophdr(v);
 218       (*p)->write_header(&ophdr);
 219       v += phdr_size;
 220     }
 221
 222   of->write_output_view(this->offset(), all_phdrs_size, view);
 223 }
 224
 225 // Output_file_header methods.
 226
 227 Output_file_header::Output_file_header(int size,
 228                                        bool big_endian,
 229                                        const General_options& options,
 230                                        const Target* target,
 231                                        const Symbol_table* symtab,
 232                                        const Output_segment_headers* osh)
 233   : size_(size),
 234     big_endian_(big_endian),
 235     options_(options),
 236     target_(target),
 237     symtab_(symtab),
 238     segment_header_(osh),
 239     section_header_(NULL),
 240     shstrtab_(NULL)
 241 {
 242   int ehdr_size;
 243   if (size == 32)
 244     ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
 245   else if (size == 64)
 246     ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
 247   else
 248     abort();
 249
 250   this->set_data_size(ehdr_size);
 251 }
 252
 253 // Set the section table information for a file header.
 254
 255 void
 256 Output_file_header::set_section_info(const Output_section_headers* shdrs,
 257                                      const Output_section* shstrtab)
 258 {
 259   this->section_header_ = shdrs;
 260   this->shstrtab_ = shstrtab;
 261 }
 262
 263 // Write out the file header.
 264
 265 void
 266 Output_file_header::do_write(Output_file* of)
 267 {
 268   if (this->size_ == 32)
 269     {
 270       if (this->big_endian_)
 271         this->do_sized_write<32, true>(of);
 272       else
 273         this->do_sized_write<32, false>(of);
 274     }
 275   else if (this->size_ == 64)
 276     {
 277       if (this->big_endian_)
 278         this->do_sized_write<64, true>(of);
 279       else
 280         this->do_sized_write<64, false>(of);
 281     }
 282   else
 283     abort();
 284 }
 285
 286 // Write out the file header with appropriate size and endianess.
 287
 288 template<int size, bool big_endian>
 289 void
 290 Output_file_header::do_sized_write(Output_file* of)
 291 {
 292   assert(this->offset() == 0);
 293
 294   int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
 295   unsigned char* view = of->get_output_view(0, ehdr_size);
 296   elfcpp::Ehdr_write<size, big_endian> oehdr(view);
 297
 298   unsigned char e_ident[elfcpp::EI_NIDENT];
 299   memset(e_ident, 0, elfcpp::EI_NIDENT);
 300   e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
 301   e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
 302   e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
 303   e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
 304   if (size == 32)
 305     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
 306   else if (size == 64)
 307     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
 308   else
 309     abort();
 310   e_ident[elfcpp::EI_DATA] = (big_endian
 311                               ? elfcpp::ELFDATA2MSB
 312                               : elfcpp::ELFDATA2LSB);
 313   e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
 314   // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
 315   oehdr.put_e_ident(e_ident);
 316
 317   elfcpp::ET e_type;
 318   // FIXME: ET_DYN.
 319   if (this->options_.is_relocatable())
 320     e_type = elfcpp::ET_REL;
 321   else
 322     e_type = elfcpp::ET_EXEC;
 323   oehdr.put_e_type(e_type);
 324
 325   oehdr.put_e_machine(this->target_->machine_code());
 326   oehdr.put_e_version(elfcpp::EV_CURRENT);
 327
 328   // FIXME: Need to support -e, and target specific entry symbol.
 329   Symbol* sym = this->symtab_->lookup("_start");
 330   typename Sized_symbol<size>::Value_type v;
 331   if (sym == NULL)
 332     v = 0;
 333   else
 334     {
 335       Sized_symbol<size>* ssym;
 336       ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME (
 337         sym SELECT_SIZE(size));
 338       v = ssym->value();
 339     }
 340   oehdr.put_e_entry(v);
 341
 342   oehdr.put_e_phoff(this->segment_header_->offset());
 343   oehdr.put_e_shoff(this->section_header_->offset());
 344
 345   // FIXME: The target needs to set the flags.
 346   oehdr.put_e_flags(0);
 347
 348   oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
 349   oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
 350   oehdr.put_e_phnum(this->segment_header_->data_size()
 351                      / elfcpp::Elf_sizes<size>::phdr_size);
 352   oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
 353   oehdr.put_e_shnum(this->section_header_->data_size()
 354                      / elfcpp::Elf_sizes<size>::shdr_size);
 355   oehdr.put_e_shstrndx(this->shstrtab_->out_shndx());
 356
 357   of->write_output_view(0, ehdr_size, view);
 358 }
 359
 360 // Output_section_got::Got_entry methods.
 361
 362 // Write out the entry.
 363
 364 template<int size, bool big_endian>
 365 void
 366 Output_section_got<size, big_endian>::Got_entry::write(unsigned char* pov)
 367     const
 368 {
 369   Valtype val = 0;
 370
 371   switch (this->local_sym_index_)
 372     {
 373     case GSYM_CODE:
 374       {
 375         Symbol* gsym = this->u_.gsym;
 376
 377         // If the symbol is resolved locally, we need to write out its
 378         // value.  Otherwise we just write zero.  The target code is
 379         // responsible for creating a relocation entry to fill in the
 380         // value at runtime.
 381         if (gsym->is_resolved_locally())
 382           {
 383             Sized_symbol<size>* sgsym;
 384             // This cast is a bit ugly.  We don't want to put a
 385             // virtual method in Symbol, because we want Symbol to be
 386             // as small as possible.
 387             sgsym = static_cast<Sized_symbol<size>*>(gsym);
 388             val = sgsym->value();
 389           }
 390       }
 391       break;
 392
 393     case CONSTANT_CODE:
 394       val = this->u_.constant;
 395       break;
 396
 397     default:
 398       abort();
 399     }
 400
 401   Valtype* povv = reinterpret_cast<Valtype*>(pov);
 402   Swap<size, big_endian>::writeval(povv, val);
 403 }
 404
 405 // Output_section_data methods.
 406
 407 unsigned int
 408 Output_section_data::do_out_shndx() const
 409 {
 410   assert(this->output_section_ != NULL);
 411   return this->output_section_->out_shndx();
 412 }
 413
 414 // Output_section_got methods.
 415
 416 // Write out the GOT.
 417
 418 template<int size, bool big_endian>
 419 void
 420 Output_section_got<size, big_endian>::do_write(Output_file* of)
 421 {
 422   const int add = size / 8;
 423
 424   const off_t off = this->offset();
 425   const off_t oview_size = this->entries_.size() * add;
 426   unsigned char* const oview = of->get_output_view(off, oview_size);
 427
 428   unsigned char* pov = oview;
 429   for (typename Got_entries::const_iterator p = this->entries_.begin();
 430        p != this->entries_.end();
 431        ++p)
 432     {
 433       p->write(pov);
 434       pov += add;
 435     }
 436
 437   of->write_output_view(off, oview_size, oview);
 438
 439   // We no longer need the GOT entries.
 440   this->entries_.clear();
 441 }
 442
 443 // Output_section::Input_section methods.
 444
 445 // Return the data size.  For an input section we store the size here.
 446 // For an Output_section_data, we have to ask it for the size.
 447
 448 off_t
 449 Output_section::Input_section::data_size() const
 450 {
 451   if (this->is_input_section())
 452     return this->data_size_;
 453   else
 454     return this->u_.posd->data_size();
 455 }
 456
 457 // Set the address and file offset.
 458
 459 void
 460 Output_section::Input_section::set_address(uint64_t addr, off_t off,
 461                                            off_t secoff)
 462 {
 463   if (this->is_input_section())
 464     this->u_.object->set_section_offset(this->shndx_, off - secoff);
 465   else
 466     this->u_.posd->set_address(addr, off);
 467 }
 468
 469 // Write out the data.  We don't have to do anything for an input
 470 // section--they are handled via Object::relocate--but this is where
 471 // we write out the data for an Output_section_data.
 472
 473 void
 474 Output_section::Input_section::write(Output_file* of)
 475 {
 476   if (!this->is_input_section())
 477     this->u_.posd->write(of);
 478 }
 479
 480 // Output_section methods.
 481
 482 // Construct an Output_section.  NAME will point into a Stringpool.
 483
 484 Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
 485                                elfcpp::Elf_Xword flags, bool may_add_data)
 486   : name_(name),
 487     addralign_(0),
 488     entsize_(0),
 489     link_(0),
 490     info_(0),
 491     type_(type),
 492     flags_(flags),
 493     out_shndx_(0),
 494     input_sections_(),
 495     first_input_offset_(0),
 496     may_add_data_(may_add_data)
 497 {
 498 }
 499
 500 Output_section::~Output_section()
 501 {
 502 }
 503
 504 // Add the input section SHNDX, with header SHDR, named SECNAME, in
 505 // OBJECT, to the Output_section.  Return the offset of the input
 506 // section within the output section.  We don't always keep track of
 507 // input sections for an Output_section.  Instead, each Object keeps
 508 // track of the Output_section for each of its input sections.
 509
 510 template<int size, bool big_endian>
 511 off_t
 512 Output_section::add_input_section(Object* object, unsigned int shndx,
 513                                   const char* secname,
 514                                   const elfcpp::Shdr<size, big_endian>& shdr)
 515 {
 516   assert(this->may_add_data_);
 517
 518   elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
 519   if ((addralign & (addralign - 1)) != 0)
 520     {
 521       fprintf(stderr, _("%s: %s: invalid alignment %lu for section \"%s\"\n"),
 522               program_name, object->name().c_str(),
 523               static_cast<unsigned long>(addralign), secname);
 524       gold_exit(false);
 525     }
 526
 527   if (addralign > this->addralign_)
 528     this->addralign_ = addralign;
 529
 530   off_t ssize = this->data_size();
 531   ssize = align_address(ssize, addralign);
 532   this->set_data_size(ssize + shdr.get_sh_size());
 533
 534   // We need to keep track of this section if we are already keeping
 535   // track of sections, or if we are relaxing.  FIXME: Add test for
 536   // relaxing.
 537   if (! this->input_sections_.empty())
 538     this->input_sections_.push_back(Input_section(object, shndx,
 539                                                   shdr.get_sh_size(),
 540                                                   addralign));
 541
 542   return ssize;
 543 }
 544
 545 // Add arbitrary data to an output section.
 546
 547 void
 548 Output_section::add_output_section_data(Output_section_data* posd)
 549 {
 550   if (this->input_sections_.empty())
 551     this->first_input_offset_ = this->data_size();
 552   this->input_sections_.push_back(Input_section(posd));
 553   uint64_t addralign = posd->addralign();
 554   if (addralign > this->addralign_)
 555     this->addralign_ = addralign;
 556   posd->set_output_section(this);
 557 }
 558
 559 // Set the address of an Output_section.  This is where we handle
 560 // setting the addresses of any Output_section_data objects.
 561
 562 void
 563 Output_section::do_set_address(uint64_t address, off_t startoff)
 564 {
 565   if (this->input_sections_.empty())
 566     return;
 567
 568   off_t off = startoff + this->first_input_offset_;
 569   for (Input_section_list::iterator p = this->input_sections_.begin();
 570        p != this->input_sections_.end();
 571        ++p)
 572     {
 573       off = align_address(off, p->addralign());
 574       p->set_address(address + (off - startoff), off, startoff);
 575       off += p->data_size();
 576     }
 577
 578   this->set_data_size(off - startoff);
 579 }
 580
 581 // Write the section header to *OSHDR.
 582
 583 template<int size, bool big_endian>
 584 void
 585 Output_section::write_header(const Stringpool* secnamepool,
 586                              elfcpp::Shdr_write<size, big_endian>* oshdr) const
 587 {
 588   oshdr->put_sh_name(secnamepool->get_offset(this->name_));
 589   oshdr->put_sh_type(this->type_);
 590   oshdr->put_sh_flags(this->flags_);
 591   oshdr->put_sh_addr(this->address());
 592   oshdr->put_sh_offset(this->offset());
 593   oshdr->put_sh_size(this->data_size());
 594   oshdr->put_sh_link(this->link_);
 595   oshdr->put_sh_info(this->info_);
 596   oshdr->put_sh_addralign(this->addralign_);
 597   oshdr->put_sh_entsize(this->entsize_);
 598 }
 599
 600 // Write out the data.  For input sections the data is written out by
 601 // Object::relocate, but we have to handle Output_section_data objects
 602 // here.
 603
 604 void
 605 Output_section::do_write(Output_file* of)
 606 {
 607   for (Input_section_list::iterator p = this->input_sections_.begin();
 608        p != this->input_sections_.end();
 609        ++p)
 610     p->write(of);
 611 }
 612
 613 // Output_section_symtab methods.
 614
 615 Output_section_symtab::Output_section_symtab(const char* name, off_t size)
 616   : Output_section(name, elfcpp::SHT_SYMTAB, 0, false)
 617 {
 618   this->set_data_size(size);
 619 }
 620
 621 // Output_section_strtab methods.
 622
 623 Output_section_strtab::Output_section_strtab(const char* name,
 624                                              Stringpool* contents)
 625   : Output_section(name, elfcpp::SHT_STRTAB, 0, false),
 626     contents_(contents)
 627 {
 628   this->set_data_size(contents->get_strtab_size());
 629 }
 630
 631 void
 632 Output_section_strtab::do_write(Output_file* of)
 633 {
 634   this->contents_->write(of, this->offset());
 635 }
 636
 637 // Output segment methods.
 638
 639 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
 640   : output_data_(),
 641     output_bss_(),
 642     vaddr_(0),
 643     paddr_(0),
 644     memsz_(0),
 645     align_(0),
 646     offset_(0),
 647     filesz_(0),
 648     type_(type),
 649     flags_(flags),
 650     is_align_known_(false)
 651 {
 652 }
 653
 654 // Add an Output_section to an Output_segment.
 655
 656 void
 657 Output_segment::add_output_section(Output_section* os,
 658                                    elfcpp::Elf_Word seg_flags)
 659 {
 660   assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
 661   assert(!this->is_align_known_);
 662
 663   // Update the segment flags.
 664   this->flags_ |= seg_flags;
 665
 666   Output_segment::Output_data_list* pdl;
 667   if (os->type() == elfcpp::SHT_NOBITS)
 668     pdl = &this->output_bss_;
 669   else
 670     pdl = &this->output_data_;
 671
 672   // So that PT_NOTE segments will work correctly, we need to ensure
 673   // that all SHT_NOTE sections are adjacent.  This will normally
 674   // happen automatically, because all the SHT_NOTE input sections
 675   // will wind up in the same output section.  However, it is possible
 676   // for multiple SHT_NOTE input sections to have different section
 677   // flags, and thus be in different output sections, but for the
 678   // different section flags to map into the same segment flags and
 679   // thus the same output segment.
 680
 681   // Note that while there may be many input sections in an output
 682   // section, there are normally only a few output sections in an
 683   // output segment.  This loop is expected to be fast.
 684
 685   if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
 686     {
 687       Layout::Data_list::iterator p = pdl->end();
 688       do
 689         {
 690           --p;
 691           if ((*p)->is_section_type(elfcpp::SHT_NOTE))
 692             {
 693               ++p;
 694               pdl->insert(p, os);
 695               return;
 696             }
 697         }
 698       while (p != pdl->begin());
 699     }
 700
 701   // Similarly, so that PT_TLS segments will work, we need to group
 702   // SHF_TLS sections.  An SHF_TLS/SHT_NOBITS section is a special
 703   // case: we group the SHF_TLS/SHT_NOBITS sections right after the
 704   // SHF_TLS/SHT_PROGBITS sections.  This lets us set up PT_TLS
 705   // correctly.
 706   if ((os->flags() & elfcpp::SHF_TLS) != 0 && !this->output_data_.empty())
 707     {
 708       pdl = &this->output_data_;
 709       bool nobits = os->type() == elfcpp::SHT_NOBITS;
 710       bool sawtls = false;
 711       Layout::Data_list::iterator p = pdl->end();
 712       do
 713         {
 714           --p;
 715           bool insert;
 716           if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
 717             {
 718               sawtls = true;
 719               // Put a NOBITS section after the first TLS section.
 720               // But a PROGBITS section after the first TLS/PROGBITS
 721               // section.
 722               insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
 723             }
 724           else
 725             {
 726               // If we've gone past the TLS sections, but we've seen a
 727               // TLS section, then we need to insert this section now.
 728               insert = sawtls;
 729             }
 730
 731           if (insert)
 732             {
 733               ++p;
 734               pdl->insert(p, os);
 735               return;
 736             }
 737         }
 738       while (p != pdl->begin());
 739
 740       // There are no TLS sections yet; put this one at the end of the
 741       // section list.
 742     }
 743
 744   pdl->push_back(os);
 745 }
 746
 747 // Add an Output_data (which is not an Output_section) to the start of
 748 // a segment.
 749
 750 void
 751 Output_segment::add_initial_output_data(Output_data* od)
 752 {
 753   assert(!this->is_align_known_);
 754   this->output_data_.push_front(od);
 755 }
 756
 757 // Return the maximum alignment of the Output_data in Output_segment.
 758 // Once we compute this, we prohibit new sections from being added.
 759
 760 uint64_t
 761 Output_segment::addralign()
 762 {
 763   if (!this->is_align_known_)
 764     {
 765       uint64_t addralign;
 766
 767       addralign = Output_segment::maximum_alignment(&this->output_data_);
 768       if (addralign > this->align_)
 769         this->align_ = addralign;
 770
 771       addralign = Output_segment::maximum_alignment(&this->output_bss_);
 772       if (addralign > this->align_)
 773         this->align_ = addralign;
 774
 775       this->is_align_known_ = true;
 776     }
 777
 778   return this->align_;
 779 }
 780
 781 // Return the maximum alignment of a list of Output_data.
 782
 783 uint64_t
 784 Output_segment::maximum_alignment(const Output_data_list* pdl)
 785 {
 786   uint64_t ret = 0;
 787   for (Output_data_list::const_iterator p = pdl->begin();
 788        p != pdl->end();
 789        ++p)
 790     {
 791       uint64_t addralign = (*p)->addralign();
 792       if (addralign > ret)
 793         ret = addralign;
 794     }
 795   return ret;
 796 }
 797
 798 // Set the section addresses for an Output_segment.  ADDR is the
 799 // address and *POFF is the file offset.  Set the section indexes
 800 // starting with *PSHNDX.  Return the address of the immediately
 801 // following segment.  Update *POFF and *PSHNDX.
 802
 803 uint64_t
 804 Output_segment::set_section_addresses(uint64_t addr, off_t* poff,
 805                                       unsigned int* pshndx)
 806 {
 807   assert(this->type_ == elfcpp::PT_LOAD);
 808
 809   this->vaddr_ = addr;
 810   this->paddr_ = addr;
 811
 812   off_t orig_off = *poff;
 813   this->offset_ = orig_off;
 814
 815   *poff = align_address(*poff, this->addralign());
 816
 817   addr = this->set_section_list_addresses(&this->output_data_, addr, poff,
 818                                           pshndx);
 819   this->filesz_ = *poff - orig_off;
 820
 821   off_t off = *poff;
 822
 823   uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr,
 824                                                   poff, pshndx);
 825   this->memsz_ = *poff - orig_off;
 826
 827   // Ignore the file offset adjustments made by the BSS Output_data
 828   // objects.
 829   *poff = off;
 830
 831   return ret;
 832 }
 833
 834 // Set the addresses in a list of Output_data structures.
 835
 836 uint64_t
 837 Output_segment::set_section_list_addresses(Output_data_list* pdl,
 838                                            uint64_t addr, off_t* poff,
 839                                            unsigned int* pshndx)
 840 {
 841   off_t startoff = *poff;
 842
 843   off_t off = startoff;
 844   for (Output_data_list::iterator p = pdl->begin();
 845        p != pdl->end();
 846        ++p)
 847     {
 848       off = align_address(off, (*p)->addralign());
 849       (*p)->set_address(addr + (off - startoff), off);
 850
 851       // Unless this is a PT_TLS segment, we want to ignore the size
 852       // of a SHF_TLS/SHT_NOBITS section.  Such a section does not
 853       // affect the size of a PT_LOAD segment.
 854       if (this->type_ == elfcpp::PT_TLS
 855           || !(*p)->is_section_flag_set(elfcpp::SHF_TLS)
 856           || !(*p)->is_section_type(elfcpp::SHT_NOBITS))
 857         off += (*p)->data_size();
 858
 859       if ((*p)->is_section())
 860         {
 861           (*p)->set_out_shndx(*pshndx);
 862           ++*pshndx;
 863         }
 864     }
 865
 866   *poff = off;
 867   return addr + (off - startoff);
 868 }
 869
 870 // For a non-PT_LOAD segment, set the offset from the sections, if
 871 // any.
 872
 873 void
 874 Output_segment::set_offset()
 875 {
 876   assert(this->type_ != elfcpp::PT_LOAD);
 877
 878   if (this->output_data_.empty() && this->output_bss_.empty())
 879     {
 880       this->vaddr_ = 0;
 881       this->paddr_ = 0;
 882       this->memsz_ = 0;
 883       this->align_ = 0;
 884       this->offset_ = 0;
 885       this->filesz_ = 0;
 886       return;
 887     }
 888
 889   const Output_data* first;
 890   if (this->output_data_.empty())
 891     first = this->output_bss_.front();
 892   else
 893     first = this->output_data_.front();
 894   this->vaddr_ = first->address();
 895   this->paddr_ = this->vaddr_;
 896   this->offset_ = first->offset();
 897
 898   if (this->output_data_.empty())
 899     this->filesz_ = 0;
 900   else
 901     {
 902       const Output_data* last_data = this->output_data_.back();
 903       this->filesz_ = (last_data->address()
 904                        + last_data->data_size()
 905                        - this->vaddr_);
 906     }
 907
 908   const Output_data* last;
 909   if (this->output_bss_.empty())
 910     last = this->output_data_.back();
 911   else
 912     last = this->output_bss_.back();
 913   this->memsz_ = (last->address()
 914                   + last->data_size()
 915                   - this->vaddr_);
 916 }
 917
 918 // Return the number of Output_sections in an Output_segment.
 919
 920 unsigned int
 921 Output_segment::output_section_count() const
 922 {
 923   return (this->output_section_count_list(&this->output_data_)
 924           + this->output_section_count_list(&this->output_bss_));
 925 }
 926
 927 // Return the number of Output_sections in an Output_data_list.
 928
 929 unsigned int
 930 Output_segment::output_section_count_list(const Output_data_list* pdl) const
 931 {
 932   unsigned int count = 0;
 933   for (Output_data_list::const_iterator p = pdl->begin();
 934        p != pdl->end();
 935        ++p)
 936     {
 937       if ((*p)->is_section())
 938         ++count;
 939     }
 940   return count;
 941 }
 942
 943 // Write the segment data into *OPHDR.
 944
 945 template<int size, bool big_endian>
 946 void
 947 Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr)
 948 {
 949   ophdr->put_p_type(this->type_);
 950   ophdr->put_p_offset(this->offset_);
 951   ophdr->put_p_vaddr(this->vaddr_);
 952   ophdr->put_p_paddr(this->paddr_);
 953   ophdr->put_p_filesz(this->filesz_);
 954   ophdr->put_p_memsz(this->memsz_);
 955   ophdr->put_p_flags(this->flags_);
 956   ophdr->put_p_align(this->addralign());
 957 }
 958
 959 // Write the section headers into V.
 960
 961 template<int size, bool big_endian>
 962 unsigned char*
 963 Output_segment::write_section_headers(const Stringpool* secnamepool,
 964                                       unsigned char* v,
 965                                       unsigned int *pshndx
 966                                       ACCEPT_SIZE_ENDIAN) const
 967 {
 968   // Every section that is attached to a segment must be attached to a
 969   // PT_LOAD segment, so we only write out section headers for PT_LOAD
 970   // segments.
 971   if (this->type_ != elfcpp::PT_LOAD)
 972     return v;
 973
 974   v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME (
 975         secnamepool, &this->output_data_, v, pshndx
 976         SELECT_SIZE_ENDIAN(size, big_endian));
 977   v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME (
 978         secnamepool, &this->output_bss_, v, pshndx
 979         SELECT_SIZE_ENDIAN(size, big_endian));
 980   return v;
 981 }
 982
 983 template<int size, bool big_endian>
 984 unsigned char*
 985 Output_segment::write_section_headers_list(const Stringpool* secnamepool,
 986                                            const Output_data_list* pdl,
 987                                            unsigned char* v,
 988                                            unsigned int* pshndx
 989                                            ACCEPT_SIZE_ENDIAN) const
 990 {
 991   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 992   for (Output_data_list::const_iterator p = pdl->begin();
 993        p != pdl->end();
 994        ++p)
 995     {
 996       if ((*p)->is_section())
 997         {
 998           const Output_section* ps = static_cast<const Output_section*>(*p);
 999           assert(*pshndx == ps->out_shndx());
1000           elfcpp::Shdr_write<size, big_endian> oshdr(v);
1001           ps->write_header(secnamepool, &oshdr);
1002           v += shdr_size;
1003           ++*pshndx;
1004         }
1005     }
1006   return v;
1007 }
1008
1009 // Output_file methods.
1010
1011 Output_file::Output_file(const General_options& options)
1012   : options_(options),
1013     name_(options.output_file_name()),
1014     o_(-1),
1015     file_size_(0),
1016     base_(NULL)
1017 {
1018 }
1019
1020 // Open the output file.
1021
1022 void
1023 Output_file::open(off_t file_size)
1024 {
1025   this->file_size_ = file_size;
1026
1027   int mode = this->options_.is_relocatable() ? 0666 : 0777;
1028   int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode);
1029   if (o < 0)
1030     {
1031       fprintf(stderr, _("%s: %s: open: %s\n"),
1032               program_name, this->name_, strerror(errno));
1033       gold_exit(false);
1034     }
1035   this->o_ = o;
1036
1037   // Write out one byte to make the file the right size.
1038   if (::lseek(o, file_size - 1, SEEK_SET) < 0)
1039     {
1040       fprintf(stderr, _("%s: %s: lseek: %s\n"),
1041               program_name, this->name_, strerror(errno));
1042       gold_exit(false);
1043     }
1044   char b = 0;
1045   if (::write(o, &b, 1) != 1)
1046     {
1047       fprintf(stderr, _("%s: %s: write: %s\n"),
1048               program_name, this->name_, strerror(errno));
1049       gold_exit(false);
1050     }
1051
1052   // Map the file into memory.
1053   void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE,
1054                       MAP_SHARED, o, 0);
1055   if (base == MAP_FAILED)
1056     {
1057       fprintf(stderr, _("%s: %s: mmap: %s\n"),
1058               program_name, this->name_, strerror(errno));
1059       gold_exit(false);
1060     }
1061   this->base_ = static_cast<unsigned char*>(base);
1062 }
1063
1064 // Close the output file.
1065
1066 void
1067 Output_file::close()
1068 {
1069   if (::munmap(this->base_, this->file_size_) < 0)
1070     {
1071       fprintf(stderr, _("%s: %s: munmap: %s\n"),
1072               program_name, this->name_, strerror(errno));
1073       gold_exit(false);
1074     }
1075   this->base_ = NULL;
1076
1077   if (::close(this->o_) < 0)
1078     {
1079       fprintf(stderr, _("%s: %s: close: %s\n"),
1080               program_name, this->name_, strerror(errno));
1081       gold_exit(false);
1082     }
1083   this->o_ = -1;
1084 }
1085
1086 // Instantiate the templates we need.  We could use the configure
1087 // script to restrict this to only the ones for implemented targets.
1088
1089 template
1090 off_t
1091 Output_section::add_input_section<32, false>(
1092     Object* object,
1093     unsigned int shndx,
1094     const char* secname,
1095     const elfcpp::Shdr<32, false>& shdr);
1096
1097 template
1098 off_t
1099 Output_section::add_input_section<32, true>(
1100     Object* object,
1101     unsigned int shndx,
1102     const char* secname,
1103     const elfcpp::Shdr<32, true>& shdr);
1104
1105 template
1106 off_t
1107 Output_section::add_input_section<64, false>(
1108     Object* object,
1109     unsigned int shndx,
1110     const char* secname,
1111     const elfcpp::Shdr<64, false>& shdr);
1112
1113 template
1114 off_t
1115 Output_section::add_input_section<64, true>(
1116     Object* object,
1117     unsigned int shndx,
1118     const char* secname,
1119     const elfcpp::Shdr<64, true>& shdr);
1120
1121 template
1122 void
1123 Output_section_got<32, false>::do_write(Output_file* of);
1124
1125 template
1126 void
1127 Output_section_got<32, true>::do_write(Output_file* of);
1128
1129 template
1130 void
1131 Output_section_got<64, false>::do_write(Output_file* of);
1132
1133 template
1134 void
1135 Output_section_got<64, true>::do_write(Output_file* of);
1136
1137 } // End namespace gold.