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 "output.h"
  14
  15 namespace gold
  16 {
  17
  18 // Output_data methods.
  19
  20 Output_data::~Output_data()
  21 {
  22 }
  23
  24 // Set the address and offset.
  25
  26 void
  27 Output_data::set_address(uint64_t addr, off_t off)
  28 {
  29   this->address_ = addr;
  30   this->offset_ = off;
  31
  32   // Let the child class know.
  33   this->do_set_address(addr, off);
  34 }
  35
  36 // Return the default alignment for a size--32 or 64.
  37
  38 uint64_t
  39 Output_data::default_alignment(int size)
  40 {
  41   if (size == 32)
  42     return 4;
  43   else if (size == 64)
  44     return 8;
  45   else
  46     abort();
  47 }
  48
  49 // Output_data_const methods.
  50
  51 void
  52 Output_data_const::do_write(Output_file* output)
  53 {
  54   output->write(this->offset(), data_.data(), data_.size());
  55 }
  56
  57 // Output_section_header methods.  This currently assumes that the
  58 // segment and section lists are complete at construction time.
  59
  60 Output_section_headers::Output_section_headers(
  61     int size,
  62     bool big_endian,
  63     const Layout::Segment_list& segment_list,
  64     const Layout::Section_list& section_list,
  65     const Stringpool* secnamepool)
  66   : size_(size),
  67     big_endian_(big_endian),
  68     segment_list_(segment_list),
  69     section_list_(section_list),
  70     secnamepool_(secnamepool)
  71 {
  72   // Count all the sections.  Start with 1 for the null section.
  73   off_t count = 1;
  74   for (Layout::Segment_list::const_iterator p = segment_list.begin();
  75        p != segment_list.end();
  76        ++p)
  77     count += (*p)->output_section_count();
  78   count += section_list.size();
  79
  80   int shdr_size;
  81   if (size == 32)
  82     shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
  83   else if (size == 64)
  84     shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
  85   else
  86     abort();
  87
  88   this->set_data_size(count * shdr_size);
  89 }
  90
  91 // Write out the section headers.
  92
  93 void
  94 Output_section_headers::do_write(Output_file* of)
  95 {
  96   if (this->size_ == 32)
  97     {
  98       if (this->big_endian_)
  99         this->do_sized_write<32, true>(of);
 100       else
 101         this->do_sized_write<32, false>(of);
 102     }
 103   else if (this->size_ == 64)
 104     {
 105       if (this->big_endian_)
 106         this->do_sized_write<64, true>(of);
 107       else
 108         this->do_sized_write<64, false>(of);
 109     }
 110   else
 111     abort();
 112 }
 113
 114 template<int size, bool big_endian>
 115 void
 116 Output_section_headers::do_sized_write(Output_file* of)
 117 {
 118   off_t all_shdrs_size = this->data_size();
 119   unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
 120
 121   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 122   unsigned char* v = view;
 123
 124   {
 125     typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
 126     oshdr.put_sh_name(0);
 127     oshdr.put_sh_type(elfcpp::SHT_NULL);
 128     oshdr.put_sh_flags(0);
 129     oshdr.put_sh_addr(0);
 130     oshdr.put_sh_offset(0);
 131     oshdr.put_sh_size(0);
 132     oshdr.put_sh_link(0);
 133     oshdr.put_sh_info(0);
 134     oshdr.put_sh_addralign(0);
 135     oshdr.put_sh_entsize(0);
 136   }
 137
 138   v += shdr_size;
 139
 140   for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
 141        p != this->segment_list_.end();
 142        ++p)
 143     v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME (
 144       this->secnamepool_, v SELECT_SIZE_ENDIAN(size, big_endian));
 145   for (Layout::Section_list::const_iterator p = this->section_list_.begin();
 146        p != this->section_list_.end();
 147        ++p)
 148     {
 149       elfcpp::Shdr_write<size, big_endian> oshdr(v);
 150       (*p)->write_header(this->secnamepool_, &oshdr);
 151       v += shdr_size;
 152     }
 153
 154   of->write_output_view(this->offset(), all_shdrs_size, view);
 155 }
 156
 157 // Output_segment_header methods.
 158
 159 Output_segment_headers::Output_segment_headers(
 160     int size,
 161     bool big_endian,
 162     const Layout::Segment_list& segment_list)
 163   : size_(size), big_endian_(big_endian), segment_list_(segment_list)
 164 {
 165   int phdr_size;
 166   if (size == 32)
 167     phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
 168   else if (size == 64)
 169     phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
 170   else
 171     abort();
 172
 173   this->set_data_size(segment_list.size() * phdr_size);
 174 }
 175
 176 void
 177 Output_segment_headers::do_write(Output_file* of)
 178 {
 179   if (this->size_ == 32)
 180     {
 181       if (this->big_endian_)
 182         this->do_sized_write<32, true>(of);
 183       else
 184         this->do_sized_write<32, false>(of);
 185     }
 186   else if (this->size_ == 64)
 187     {
 188       if (this->big_endian_)
 189         this->do_sized_write<64, true>(of);
 190       else
 191         this->do_sized_write<64, false>(of);
 192     }
 193   else
 194     abort();
 195 }
 196
 197 template<int size, bool big_endian>
 198 void
 199 Output_segment_headers::do_sized_write(Output_file* of)
 200 {
 201   const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
 202   off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
 203   unsigned char* view = of->get_output_view(this->offset(),
 204                                             all_phdrs_size);
 205   unsigned char* v = view;
 206   for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
 207        p != this->segment_list_.end();
 208        ++p)
 209     {
 210       elfcpp::Phdr_write<size, big_endian> ophdr(v);
 211       (*p)->write_header(&ophdr);
 212       v += phdr_size;
 213     }
 214
 215   of->write_output_view(this->offset(), all_phdrs_size, view);
 216 }
 217
 218 // Output_file_header methods.
 219
 220 Output_file_header::Output_file_header(int size,
 221                                        bool big_endian,
 222                                        const General_options& options,
 223                                        const Target* target,
 224                                        const Symbol_table* symtab,
 225                                        const Output_segment_headers* osh)
 226   : size_(size),
 227     big_endian_(big_endian),
 228     options_(options),
 229     target_(target),
 230     symtab_(symtab),
 231     segment_header_(osh),
 232     section_header_(NULL),
 233     shstrtab_(NULL)
 234 {
 235   int ehdr_size;
 236   if (size == 32)
 237     ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
 238   else if (size == 64)
 239     ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
 240   else
 241     abort();
 242
 243   this->set_data_size(ehdr_size);
 244 }
 245
 246 // Set the section table information for a file header.
 247
 248 void
 249 Output_file_header::set_section_info(const Output_section_headers* shdrs,
 250                                      const Output_section* shstrtab)
 251 {
 252   this->section_header_ = shdrs;
 253   this->shstrtab_ = shstrtab;
 254 }
 255
 256 // Write out the file header.
 257
 258 void
 259 Output_file_header::do_write(Output_file* of)
 260 {
 261   if (this->size_ == 32)
 262     {
 263       if (this->big_endian_)
 264         this->do_sized_write<32, true>(of);
 265       else
 266         this->do_sized_write<32, false>(of);
 267     }
 268   else if (this->size_ == 64)
 269     {
 270       if (this->big_endian_)
 271         this->do_sized_write<64, true>(of);
 272       else
 273         this->do_sized_write<64, false>(of);
 274     }
 275   else
 276     abort();
 277 }
 278
 279 // Write out the file header with appropriate size and endianess.
 280
 281 template<int size, bool big_endian>
 282 void
 283 Output_file_header::do_sized_write(Output_file* of)
 284 {
 285   assert(this->offset() == 0);
 286
 287   int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
 288   unsigned char* view = of->get_output_view(0, ehdr_size);
 289   elfcpp::Ehdr_write<size, big_endian> oehdr(view);
 290
 291   unsigned char e_ident[elfcpp::EI_NIDENT];
 292   memset(e_ident, 0, elfcpp::EI_NIDENT);
 293   e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
 294   e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
 295   e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
 296   e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
 297   if (size == 32)
 298     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
 299   else if (size == 64)
 300     e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
 301   else
 302     abort();
 303   e_ident[elfcpp::EI_DATA] = (big_endian
 304                               ? elfcpp::ELFDATA2MSB
 305                               : elfcpp::ELFDATA2LSB);
 306   e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
 307   // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
 308   oehdr.put_e_ident(e_ident);
 309
 310   elfcpp::ET e_type;
 311   // FIXME: ET_DYN.
 312   if (this->options_.is_relocatable())
 313     e_type = elfcpp::ET_REL;
 314   else
 315     e_type = elfcpp::ET_EXEC;
 316   oehdr.put_e_type(e_type);
 317
 318   oehdr.put_e_machine(this->target_->machine_code());
 319   oehdr.put_e_version(elfcpp::EV_CURRENT);
 320
 321   Symbol* sym = this->symtab_->lookup("_start");
 322   typename Sized_symbol<size>::Value_type v;
 323   if (sym == NULL)
 324     v = 0;
 325   else
 326     {
 327       Sized_symbol<size>* ssym;
 328       ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME (
 329         sym SELECT_SIZE(size));
 330       v = ssym->value();
 331     }
 332   oehdr.put_e_entry(v);
 333
 334   oehdr.put_e_phoff(this->segment_header_->offset());
 335   oehdr.put_e_shoff(this->section_header_->offset());
 336
 337   // FIXME: The target needs to set the flags.
 338   oehdr.put_e_flags(0);
 339
 340   oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
 341   oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
 342   oehdr.put_e_phnum(this->segment_header_->data_size()
 343                      / elfcpp::Elf_sizes<size>::phdr_size);
 344   oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
 345   oehdr.put_e_shnum(this->section_header_->data_size()
 346                      / elfcpp::Elf_sizes<size>::shdr_size);
 347   oehdr.put_e_shstrndx(this->shstrtab_->shndx());
 348
 349   of->write_output_view(0, ehdr_size, view);
 350 }
 351
 352 // Output_section methods.
 353
 354 // Construct an Output_section.  NAME will point into a Stringpool.
 355
 356 Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
 357                                elfcpp::Elf_Xword flags, unsigned int shndx)
 358   : name_(name),
 359     addralign_(0),
 360     entsize_(0),
 361     link_(0),
 362     info_(0),
 363     type_(type),
 364     flags_(flags),
 365     shndx_(shndx)
 366 {
 367 }
 368
 369 Output_section::~Output_section()
 370 {
 371 }
 372
 373 // Add an input section to an Output_section.  We don't keep track of
 374 // input sections for an Output_section.  Instead, each Object keeps
 375 // track of the Output_section for each of its input sections.
 376
 377 template<int size, bool big_endian>
 378 off_t
 379 Output_section::add_input_section(Object* object, const char* secname,
 380                                   const elfcpp::Shdr<size, big_endian>& shdr)
 381 {
 382   elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
 383   if ((addralign & (addralign - 1)) != 0)
 384     {
 385       fprintf(stderr, _("%s: %s: invalid alignment %lu for section \"%s\"\n"),
 386               program_name, object->name().c_str(),
 387               static_cast<unsigned long>(addralign), secname);
 388       gold_exit(false);
 389     }
 390
 391   if (addralign > this->addralign_)
 392     this->addralign_ = addralign;
 393
 394   off_t ssize = this->data_size();
 395   ssize = (ssize + addralign - 1) &~ (addralign - 1);
 396
 397   // SHF_TLS/SHT_NOBITS sections are handled specially: they are
 398   // treated as having no size and taking up no space.  We only use
 399   // the real size when setting the pt_memsz field of the PT_TLS
 400   // segment.
 401   if ((this->flags_ & elfcpp::SHF_TLS) == 0
 402       || this->type_ != elfcpp::SHT_NOBITS)
 403     this->set_data_size(ssize + shdr.get_sh_size());
 404
 405   return ssize;
 406 }
 407
 408 // Write the section header to *OSHDR.
 409
 410 template<int size, bool big_endian>
 411 void
 412 Output_section::write_header(const Stringpool* secnamepool,
 413                              elfcpp::Shdr_write<size, big_endian>* oshdr) const
 414 {
 415   oshdr->put_sh_name(secnamepool->get_offset(this->name_));
 416   oshdr->put_sh_type(this->type_);
 417   oshdr->put_sh_flags(this->flags_);
 418   oshdr->put_sh_addr(this->address());
 419   oshdr->put_sh_offset(this->offset());
 420   oshdr->put_sh_size(this->data_size());
 421   oshdr->put_sh_link(this->link_);
 422   oshdr->put_sh_info(this->info_);
 423   oshdr->put_sh_addralign(this->addralign_);
 424   oshdr->put_sh_entsize(this->entsize_);
 425 }
 426
 427 // Output_section_symtab methods.
 428
 429 Output_section_symtab::Output_section_symtab(const char* name, off_t size,
 430                                              unsigned int shndx)
 431   : Output_section(name, elfcpp::SHT_SYMTAB, 0, shndx)
 432 {
 433   this->set_data_size(size);
 434 }
 435
 436 // Output_section_strtab methods.
 437
 438 Output_section_strtab::Output_section_strtab(const char* name,
 439                                              Stringpool* contents,
 440                                              unsigned int shndx)
 441   : Output_section(name, elfcpp::SHT_STRTAB, 0, shndx),
 442     contents_(contents)
 443 {
 444   this->set_data_size(contents->get_strtab_size());
 445 }
 446
 447 void
 448 Output_section_strtab::do_write(Output_file* of)
 449 {
 450   this->contents_->write(of, this->offset());
 451 }
 452
 453 // Output segment methods.
 454
 455 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
 456   : output_data_(),
 457     output_bss_(),
 458     vaddr_(0),
 459     paddr_(0),
 460     memsz_(0),
 461     align_(0),
 462     offset_(0),
 463     filesz_(0),
 464     type_(type),
 465     flags_(flags)
 466 {
 467 }
 468
 469 // Add an Output_section to an Output_segment.
 470
 471 void
 472 Output_segment::add_output_section(Output_section* os,
 473                                    elfcpp::Elf_Word seg_flags)
 474 {
 475   assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
 476
 477   // Update the segment flags and alignment.
 478   this->flags_ |= seg_flags;
 479   uint64_t addralign = os->addralign();
 480   if (addralign > this->align_)
 481     this->align_ = addralign;
 482
 483   Output_segment::Output_data_list* pdl;
 484   if (os->type() == elfcpp::SHT_NOBITS)
 485     pdl = &this->output_bss_;
 486   else
 487     pdl = &this->output_data_;
 488
 489   // So that PT_NOTE segments will work correctly, we need to ensure
 490   // that all SHT_NOTE sections are adjacent.  This will normally
 491   // happen automatically, because all the SHT_NOTE input sections
 492   // will wind up in the same output section.  However, it is possible
 493   // for multiple SHT_NOTE input sections to have different section
 494   // flags, and thus be in different output sections, but for the
 495   // different section flags to map into the same segment flags and
 496   // thus the same output segment.
 497
 498   // Note that while there may be many input sections in an output
 499   // section, there are normally only a few output sections in an
 500   // output segment.  This loop is expected to be fast.
 501
 502   if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
 503     {
 504       Layout::Data_list::iterator p = pdl->end();
 505       do
 506         {
 507           --p;
 508           if ((*p)->is_section_type(elfcpp::SHT_NOTE))
 509             {
 510               ++p;
 511               pdl->insert(p, os);
 512               return;
 513             }
 514         }
 515       while (p != pdl->begin());
 516     }
 517
 518   // Similarly, so that PT_TLS segments will work, we need to group
 519   // SHF_TLS sections.  An SHF_TLS/SHT_NOBITS section is a special
 520   // case: we group the SHF_TLS/SHT_NOBITS sections right after the
 521   // SHF_TLS/SHT_PROGBITS sections.  This lets us set up PT_TLS
 522   // correctly.
 523   if ((os->flags() & elfcpp::SHF_TLS) != 0 && !this->output_data_.empty())
 524     {
 525       pdl = &this->output_data_;
 526       bool nobits = os->type() == elfcpp::SHT_NOBITS;
 527       Layout::Data_list::iterator p = pdl->end();
 528       do
 529         {
 530           --p;
 531           if ((*p)->is_section_flag_set(elfcpp::SHF_TLS)
 532               && (nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS)))
 533             {
 534               ++p;
 535               pdl->insert(p, os);
 536               return;
 537             }
 538         }
 539       while (p != pdl->begin());
 540     }
 541
 542   pdl->push_back(os);
 543 }
 544
 545 // Add an Output_data (which is not an Output_section) to the start of
 546 // a segment.
 547
 548 void
 549 Output_segment::add_initial_output_data(Output_data* od)
 550 {
 551   uint64_t addralign = od->addralign();
 552   if (addralign > this->align_)
 553     this->align_ = addralign;
 554
 555   this->output_data_.push_front(od);
 556 }
 557
 558 // Return the maximum alignment of the Output_data in Output_segment.
 559 // We keep this up to date as we add Output_sections and Output_data.
 560
 561 uint64_t
 562 Output_segment::max_data_align() const
 563 {
 564   return this->align_;
 565 }
 566
 567 // Set the section addresses for an Output_segment.  ADDR is the
 568 // address and *POFF is the file offset.  Return the address of the
 569 // immediately following segment.  Update *POFF.
 570
 571 uint64_t
 572 Output_segment::set_section_addresses(uint64_t addr, off_t* poff)
 573 {
 574   assert(this->type_ == elfcpp::PT_LOAD);
 575
 576   this->vaddr_ = addr;
 577   this->paddr_ = addr;
 578
 579   off_t orig_off = *poff;
 580   this->offset_ = orig_off;
 581
 582   addr = this->set_section_list_addresses(&this->output_data_, addr, poff);
 583   this->filesz_ = *poff - orig_off;
 584
 585   off_t off = *poff;
 586
 587   uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr,
 588                                                   poff);
 589   this->memsz_ = *poff - orig_off;
 590
 591   // Ignore the file offset adjustments made by the BSS Output_data
 592   // objects.
 593   *poff = off;
 594
 595   return ret;
 596 }
 597
 598 // Set the addresses in a list of Output_data structures.
 599
 600 uint64_t
 601 Output_segment::set_section_list_addresses(Output_data_list* pdl,
 602                                            uint64_t addr, off_t* poff)
 603 {
 604   off_t off = *poff;
 605
 606   for (Output_data_list::iterator p = pdl->begin();
 607        p != pdl->end();
 608        ++p)
 609     {
 610       uint64_t addralign = (*p)->addralign();
 611       addr = (addr + addralign - 1) & ~ (addralign - 1);
 612       off = (off + addralign - 1) & ~ (addralign - 1);
 613       (*p)->set_address(addr, off);
 614
 615       uint64_t size = (*p)->data_size();
 616       addr += size;
 617       off += size;
 618     }
 619
 620   *poff = off;
 621   return addr;
 622 }
 623
 624 // For a non-PT_LOAD segment, set the offset from the sections, if
 625 // any.
 626
 627 void
 628 Output_segment::set_offset()
 629 {
 630   assert(this->type_ != elfcpp::PT_LOAD);
 631
 632   if (this->output_data_.empty() && this->output_bss_.empty())
 633     {
 634       this->vaddr_ = 0;
 635       this->paddr_ = 0;
 636       this->memsz_ = 0;
 637       this->align_ = 0;
 638       this->offset_ = 0;
 639       this->filesz_ = 0;
 640       return;
 641     }
 642
 643   const Output_data* first;
 644   if (this->output_data_.empty())
 645     first = this->output_bss_.front();
 646   else
 647     first = this->output_data_.front();
 648   this->vaddr_ = first->address();
 649   this->paddr_ = this->vaddr_;
 650   this->offset_ = first->offset();
 651
 652   if (this->output_data_.empty())
 653     this->filesz_ = 0;
 654   else
 655     {
 656       const Output_data* last_data = this->output_data_.back();
 657       this->filesz_ = (last_data->address()
 658                        + last_data->data_size()
 659                        - this->vaddr_);
 660     }
 661
 662   const Output_data* last;
 663   if (this->output_bss_.empty())
 664     last = this->output_data_.back();
 665   else
 666     last = this->output_bss_.back();
 667   this->memsz_ = (last->address()
 668                   + last->data_size()
 669                   - this->vaddr_);
 670
 671   // this->align_ was set as we added items.
 672 }
 673
 674 // Return the number of Output_sections in an Output_segment.
 675
 676 unsigned int
 677 Output_segment::output_section_count() const
 678 {
 679   return (this->output_section_count_list(&this->output_data_)
 680           + this->output_section_count_list(&this->output_bss_));
 681 }
 682
 683 // Return the number of Output_sections in an Output_data_list.
 684
 685 unsigned int
 686 Output_segment::output_section_count_list(const Output_data_list* pdl) const
 687 {
 688   unsigned int count = 0;
 689   for (Output_data_list::const_iterator p = pdl->begin();
 690        p != pdl->end();
 691        ++p)
 692     {
 693       if ((*p)->is_section())
 694         ++count;
 695     }
 696   return count;
 697 }
 698
 699 // Write the segment data into *OPHDR.
 700
 701 template<int size, bool big_endian>
 702 void
 703 Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr) const
 704 {
 705   ophdr->put_p_type(this->type_);
 706   ophdr->put_p_offset(this->offset_);
 707   ophdr->put_p_vaddr(this->vaddr_);
 708   ophdr->put_p_paddr(this->paddr_);
 709   ophdr->put_p_filesz(this->filesz_);
 710   ophdr->put_p_memsz(this->memsz_);
 711   ophdr->put_p_flags(this->flags_);
 712   ophdr->put_p_align(this->align_);
 713 }
 714
 715 // Write the section headers into V.
 716
 717 template<int size, bool big_endian>
 718 unsigned char*
 719 Output_segment::write_section_headers(const Stringpool* secnamepool,
 720                                       unsigned char* v
 721                                       ACCEPT_SIZE_ENDIAN) const
 722 {
 723   v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME (
 724     secnamepool, &this->output_data_, v SELECT_SIZE_ENDIAN(size, big_endian));
 725   v = this->write_section_headers_list SELECT_SIZE_ENDIAN_NAME (
 726     secnamepool, &this->output_bss_, v SELECT_SIZE_ENDIAN(size, big_endian));
 727   return v;
 728 }
 729
 730 template<int size, bool big_endian>
 731 unsigned char*
 732 Output_segment::write_section_headers_list(const Stringpool* secnamepool,
 733                                            const Output_data_list* pdl,
 734                                            unsigned char* v
 735                                            ACCEPT_SIZE_ENDIAN) const
 736 {
 737   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 738   for (Output_data_list::const_iterator p = pdl->begin();
 739        p != pdl->end();
 740        ++p)
 741     {
 742       if ((*p)->is_section())
 743         {
 744           const Output_section* ps = static_cast<const Output_section*>(*p);
 745           elfcpp::Shdr_write<size, big_endian> oshdr(v);
 746           ps->write_header(secnamepool, &oshdr);
 747           v += shdr_size;
 748         }
 749     }
 750   return v;
 751 }
 752
 753 // Output_file methods.
 754
 755 Output_file::Output_file(const General_options& options)
 756   : options_(options),
 757     name_(options.output_file_name()),
 758     o_(-1),
 759     file_size_(0),
 760     base_(NULL)
 761 {
 762 }
 763
 764 // Open the output file.
 765
 766 void
 767 Output_file::open(off_t file_size)
 768 {
 769   this->file_size_ = file_size;
 770
 771   int mode = this->options_.is_relocatable() ? 0666 : 0777;
 772   int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode);
 773   if (o < 0)
 774     {
 775       fprintf(stderr, _("%s: %s: open: %s\n"),
 776               program_name, this->name_, strerror(errno));
 777       gold_exit(false);
 778     }
 779   this->o_ = o;
 780
 781   // Write out one byte to make the file the right size.
 782   if (::lseek(o, file_size - 1, SEEK_SET) < 0)
 783     {
 784       fprintf(stderr, _("%s: %s: lseek: %s\n"),
 785               program_name, this->name_, strerror(errno));
 786       gold_exit(false);
 787     }
 788   char b = 0;
 789   if (::write(o, &b, 1) != 1)
 790     {
 791       fprintf(stderr, _("%s: %s: write: %s\n"),
 792               program_name, this->name_, strerror(errno));
 793       gold_exit(false);
 794     }
 795
 796   // Map the file into memory.
 797   void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE,
 798                       MAP_SHARED, o, 0);
 799   if (base == MAP_FAILED)
 800     {
 801       fprintf(stderr, _("%s: %s: mmap: %s\n"),
 802               program_name, this->name_, strerror(errno));
 803       gold_exit(false);
 804     }
 805   this->base_ = static_cast<unsigned char*>(base);
 806 }
 807
 808 // Close the output file.
 809
 810 void
 811 Output_file::close()
 812 {
 813   if (::munmap(this->base_, this->file_size_) < 0)
 814     {
 815       fprintf(stderr, _("%s: %s: munmap: %s\n"),
 816               program_name, this->name_, strerror(errno));
 817       gold_exit(false);
 818     }
 819   this->base_ = NULL;
 820
 821   if (::close(this->o_) < 0)
 822     {
 823       fprintf(stderr, _("%s: %s: close: %s\n"),
 824               program_name, this->name_, strerror(errno));
 825       gold_exit(false);
 826     }
 827   this->o_ = -1;
 828 }
 829
 830 // Instantiate the templates we need.  We could use the configure
 831 // script to restrict this to only the ones for implemented targets.
 832
 833 template
 834 off_t
 835 Output_section::add_input_section<32, false>(
 836     Object* object,
 837     const char* secname,
 838     const elfcpp::Shdr<32, false>& shdr);
 839
 840 template
 841 off_t
 842 Output_section::add_input_section<32, true>(
 843     Object* object,
 844     const char* secname,
 845     const elfcpp::Shdr<32, true>& shdr);
 846
 847 template
 848 off_t
 849 Output_section::add_input_section<64, false>(
 850     Object* object,
 851     const char* secname,
 852     const elfcpp::Shdr<64, false>& shdr);
 853
 854 template
 855 off_t
 856 Output_section::add_input_section<64, true>(
 857     Object* object,
 858     const char* secname,
 859     const elfcpp::Shdr<64, true>& shdr);
 860
 861 } // End namespace gold.