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