gold/layout.h

   1 // layout.h -- lay out output file sections for gold  -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008 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 #ifndef GOLD_LAYOUT_H
  24 #define GOLD_LAYOUT_H
  25
  26 #include <cstring>
  27 #include <list>
  28 #include <string>
  29 #include <utility>
  30 #include <vector>
  31
  32 #include "script.h"
  33 #include "workqueue.h"
  34 #include "object.h"
  35 #include "dynobj.h"
  36 #include "stringpool.h"
  37
  38 namespace gold
  39 {
  40
  41 class General_options;
  42 class Input_objects;
  43 class Symbol_table;
  44 class Output_section_data;
  45 class Output_section;
  46 class Output_section_headers;
  47 class Output_segment;
  48 class Output_data;
  49 class Output_data_dynamic;
  50 class Output_symtab_xindex;
  51 class Eh_frame;
  52 class Target;
  53
  54 // This task function handles mapping the input sections to output
  55 // sections and laying them out in memory.
  56
  57 class Layout_task_runner : public Task_function_runner
  58 {
  59  public:
  60   // OPTIONS is the command line options, INPUT_OBJECTS is the list of
  61   // input objects, SYMTAB is the symbol table, LAYOUT is the layout
  62   // object.
  63   Layout_task_runner(const General_options& options,
  64                      const Input_objects* input_objects,
  65                      Symbol_table* symtab,
  66                      Target* target,
  67                      Layout* layout)
  68     : options_(options), input_objects_(input_objects), symtab_(symtab),
  69       target_(target), layout_(layout)
  70   { }
  71
  72   // Run the operation.
  73   void
  74   run(Workqueue*, const Task*);
  75
  76  private:
  77   Layout_task_runner(const Layout_task_runner&);
  78   Layout_task_runner& operator=(const Layout_task_runner&);
  79
  80   const General_options& options_;
  81   const Input_objects* input_objects_;
  82   Symbol_table* symtab_;
  83   Target* target_;
  84   Layout* layout_;
  85 };
  86
  87 // This class handles the details of laying out input sections.
  88
  89 class Layout
  90 {
  91  public:
  92   Layout(const General_options& options, Script_options*);
  93
  94   // Given an input section SHNDX, named NAME, with data in SHDR, from
  95   // the object file OBJECT, return the output section where this
  96   // input section should go.  RELOC_SHNDX is the index of a
  97   // relocation section which applies to this section, or 0 if none,
  98   // or -1U if more than one.  RELOC_TYPE is the type of the
  99   // relocation section if there is one.  Set *OFFSET to the offset
 100   // within the output section.
 101   template<int size, bool big_endian>
 102   Output_section*
 103   layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
 104          const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 105          unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
 106
 107   // Layout an input reloc section when doing a relocatable link.  The
 108   // section is RELOC_SHNDX in OBJECT, with data in SHDR.
 109   // DATA_SECTION is the reloc section to which it refers.  RR is the
 110   // relocatable information.
 111   template<int size, bool big_endian>
 112   Output_section*
 113   layout_reloc(Sized_relobj<size, big_endian>* object,
 114                unsigned int reloc_shndx,
 115                const elfcpp::Shdr<size, big_endian>& shdr,
 116                Output_section* data_section,
 117                Relocatable_relocs* rr);
 118
 119   // Layout a group section when doing a relocatable link.
 120   template<int size, bool big_endian>
 121   void
 122   layout_group(Symbol_table* symtab,
 123                Sized_relobj<size, big_endian>* object,
 124                unsigned int group_shndx,
 125                const char* group_section_name,
 126                const char* signature,
 127                const elfcpp::Shdr<size, big_endian>& shdr,
 128                elfcpp::Elf_Word flags,
 129                std::vector<unsigned int>* shndxes);
 130
 131   // Like layout, only for exception frame sections.  OBJECT is an
 132   // object file.  SYMBOLS is the contents of the symbol table
 133   // section, with size SYMBOLS_SIZE.  SYMBOL_NAMES is the contents of
 134   // the symbol name section, with size SYMBOL_NAMES_SIZE.  SHNDX is a
 135   // .eh_frame section in OBJECT.  SHDR is the section header.
 136   // RELOC_SHNDX is the index of a relocation section which applies to
 137   // this section, or 0 if none, or -1U if more than one.  RELOC_TYPE
 138   // is the type of the relocation section if there is one.  This
 139   // returns the output section, and sets *OFFSET to the offset.
 140   template<int size, bool big_endian>
 141   Output_section*
 142   layout_eh_frame(Sized_relobj<size, big_endian>* object,
 143                   const unsigned char* symbols,
 144                   off_t symbols_size,
 145                   const unsigned char* symbol_names,
 146                   off_t symbol_names_size,
 147                   unsigned int shndx,
 148                   const elfcpp::Shdr<size, big_endian>& shdr,
 149                   unsigned int reloc_shndx, unsigned int reloc_type,
 150                   off_t* offset);
 151
 152   // Handle a GNU stack note.  This is called once per input object
 153   // file.  SEEN_GNU_STACK is true if the object file has a
 154   // .note.GNU-stack section.  GNU_STACK_FLAGS is the section flags
 155   // from that section if there was one.
 156   void
 157   layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
 158
 159   // Add an Output_section_data to the layout.  This is used for
 160   // special sections like the GOT section.
 161   Output_section*
 162   add_output_section_data(const char* name, elfcpp::Elf_Word type,
 163                           elfcpp::Elf_Xword flags,
 164                           Output_section_data*);
 165
 166   // Create dynamic sections if necessary.
 167   void
 168   create_initial_dynamic_sections(Symbol_table*);
 169
 170   // Define __start and __stop symbols for output sections.
 171   void
 172   define_section_symbols(Symbol_table*);
 173
 174   // Create sections for linker scripts.
 175   void
 176   create_script_sections()
 177   { this->script_options_->create_script_sections(this); }
 178
 179   // Define symbols from any linker script.
 180   void
 181   define_script_symbols(Symbol_table* symtab)
 182   { this->script_options_->add_symbols_to_table(symtab); }
 183
 184   // Define symbols for group signatures.
 185   void
 186   define_group_signatures(Symbol_table*);
 187
 188   // Return the Stringpool used for symbol names.
 189   const Stringpool*
 190   sympool() const
 191   { return &this->sympool_; }
 192
 193   // Return the Stringpool used for dynamic symbol names and dynamic
 194   // tags.
 195   const Stringpool*
 196   dynpool() const
 197   { return &this->dynpool_; }
 198
 199   // Return the symtab_xindex section used to hold large section
 200   // indexes for the normal symbol table.
 201   Output_symtab_xindex*
 202   symtab_xindex() const
 203   { return this->symtab_xindex_; }
 204
 205   // Return the dynsym_xindex section used to hold large section
 206   // indexes for the dynamic symbol table.
 207   Output_symtab_xindex*
 208   dynsym_xindex() const
 209   { return this->dynsym_xindex_; }
 210
 211   // Return whether a section is a .gnu.linkonce section, given the
 212   // section name.
 213   static inline bool
 214   is_linkonce(const char* name)
 215   { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
 216
 217   // Return true if a section is a debugging section.
 218   static inline bool
 219   is_debug_info_section(const char* name)
 220   {
 221     // Debugging sections can only be recognized by name.
 222     return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
 223             || strncmp(name, ".gnu.linkonce.wi.",
 224                        sizeof(".gnu.linkonce.wi.") - 1) == 0
 225             || strncmp(name, ".line", sizeof(".line") - 1) == 0
 226             || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
 227   }
 228
 229   // Record the signature of a comdat section, and return whether to
 230   // include it in the link.  The GROUP parameter is true for a
 231   // section group signature, false for a signature derived from a
 232   // .gnu.linkonce section.
 233   bool
 234   add_comdat(Relobj*, unsigned int, const std::string&, bool group);
 235
 236   // Find the given comdat signature, and return the object and section
 237   // index of the kept group.
 238   Relobj*
 239   find_kept_object(const std::string&, unsigned int*) const;
 240
 241   // Finalize the layout after all the input sections have been added.
 242   off_t
 243   finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
 244
 245   // Return whether any sections require postprocessing.
 246   bool
 247   any_postprocessing_sections() const
 248   { return this->any_postprocessing_sections_; }
 249
 250   // Return the size of the output file.
 251   off_t
 252   output_file_size() const
 253   { return this->output_file_size_; }
 254
 255   // Return the TLS segment.  This will return NULL if there isn't
 256   // one.
 257   Output_segment*
 258   tls_segment() const
 259   { return this->tls_segment_; }
 260
 261   // Return the normal symbol table.
 262   Output_section*
 263   symtab_section() const
 264   {
 265     gold_assert(this->symtab_section_ != NULL);
 266     return this->symtab_section_;
 267   }
 268
 269   // Return the dynamic symbol table.
 270   Output_section*
 271   dynsym_section() const
 272   {
 273     gold_assert(this->dynsym_section_ != NULL);
 274     return this->dynsym_section_;
 275   }
 276
 277   // Return the dynamic tags.
 278   Output_data_dynamic*
 279   dynamic_data() const
 280   { return this->dynamic_data_; }
 281
 282   // Write out the output sections.
 283   void
 284   write_output_sections(Output_file* of) const;
 285
 286   // Write out data not associated with an input file or the symbol
 287   // table.
 288   void
 289   write_data(const Symbol_table*, Output_file*) const;
 290
 291   // Write out output sections which can not be written until all the
 292   // input sections are complete.
 293   void
 294   write_sections_after_input_sections(Output_file* of);
 295
 296   // Return an output section named NAME, or NULL if there is none.
 297   Output_section*
 298   find_output_section(const char* name) const;
 299
 300   // Return an output segment of type TYPE, with segment flags SET set
 301   // and segment flags CLEAR clear.  Return NULL if there is none.
 302   Output_segment*
 303   find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
 304                       elfcpp::Elf_Word clear) const;
 305
 306   // Return the number of segments we expect to produce.
 307   size_t
 308   expected_segment_count() const;
 309
 310   // Set a flag to indicate that an object file uses the static TLS model.
 311   void
 312   set_has_static_tls()
 313   { this->has_static_tls_ = true; }
 314
 315   // Return true if any object file uses the static TLS model.
 316   bool
 317   has_static_tls() const
 318   { return this->has_static_tls_; }
 319
 320   // Return the options which may be set by a linker script.
 321   Script_options*
 322   script_options()
 323   { return this->script_options_; }
 324
 325   const Script_options*
 326   script_options() const
 327   { return this->script_options_; }
 328
 329   // Compute and write out the build ID if needed.
 330   void
 331   write_build_id(Output_file*) const;
 332
 333   // Rewrite output file in binary format.
 334   void
 335   write_binary(Output_file* in) const;
 336
 337   // Dump statistical information to stderr.
 338   void
 339   print_stats() const;
 340
 341   // A list of segments.
 342
 343   typedef std::vector<Output_segment*> Segment_list;
 344
 345   // A list of sections.
 346
 347   typedef std::vector<Output_section*> Section_list;
 348
 349   // The list of information to write out which is not attached to
 350   // either a section or a segment.
 351   typedef std::vector<Output_data*> Data_list;
 352
 353   // Store the allocated sections into the section list.  This is used
 354   // by the linker script code.
 355   void
 356   get_allocated_sections(Section_list*) const;
 357
 358   // Make a section for a linker script to hold data.
 359   Output_section*
 360   make_output_section_for_script(const char* name);
 361
 362   // Make a segment.  This is used by the linker script code.
 363   Output_segment*
 364   make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
 365
 366   // Return the number of segments.
 367   size_t
 368   segment_count() const
 369   { return this->segment_list_.size(); }
 370
 371   // Map from section flags to segment flags.
 372   static elfcpp::Elf_Word
 373   section_flags_to_segment(elfcpp::Elf_Xword flags);
 374
 375   // Attach sections to segments.
 376   void
 377   attach_sections_to_segments();
 378
 379  private:
 380   Layout(const Layout&);
 381   Layout& operator=(const Layout&);
 382
 383   // Mapping from .gnu.linkonce section names to output section names.
 384   struct Linkonce_mapping
 385   {
 386     const char* from;
 387     int fromlen;
 388     const char* to;
 389     int tolen;
 390   };
 391   static const Linkonce_mapping linkonce_mapping[];
 392   static const int linkonce_mapping_count;
 393
 394   // During a relocatable link, a list of group sections and
 395   // signatures.
 396   struct Group_signature
 397   {
 398     // The group section.
 399     Output_section* section;
 400     // The signature.
 401     const char* signature;
 402
 403     Group_signature()
 404       : section(NULL), signature(NULL)
 405     { }
 406
 407     Group_signature(Output_section* sectiona, const char* signaturea)
 408       : section(sectiona), signature(signaturea)
 409     { }
 410   };
 411   typedef std::vector<Group_signature> Group_signatures;
 412
 413   // Create a .note section, filling in the header.
 414   Output_section*
 415   create_note(const char* name, int note_type, size_t descsz,
 416               bool allocate, size_t* trailing_padding);
 417
 418   // Create a .note section for gold.
 419   void
 420   create_gold_note();
 421
 422   // Record whether the stack must be executable.
 423   void
 424   create_executable_stack_info(const Target*);
 425
 426   // Create a build ID note if needed.
 427   void
 428   create_build_id();
 429
 430   // Find the first read-only PT_LOAD segment, creating one if
 431   // necessary.
 432   Output_segment*
 433   find_first_load_seg();
 434
 435   // Count the local symbols in the regular symbol table and the dynamic
 436   // symbol table, and build the respective string pools.
 437   void
 438   count_local_symbols(const Task*, const Input_objects*);
 439
 440   // Create the output sections for the symbol table.
 441   void
 442   create_symtab_sections(const Input_objects*, Symbol_table*,
 443                          unsigned int, off_t*);
 444
 445   // Create the .shstrtab section.
 446   Output_section*
 447   create_shstrtab();
 448
 449   // Create the section header table.
 450   void
 451   create_shdrs(const Output_section* shstrtab_section, off_t*);
 452
 453   // Create the dynamic symbol table.
 454   void
 455   create_dynamic_symtab(const Input_objects*, Symbol_table*,
 456                         Output_section** pdynstr,
 457                         unsigned int* plocal_dynamic_count,
 458                         std::vector<Symbol*>* pdynamic_symbols,
 459                         Versions* versions);
 460
 461   // Assign offsets to each local portion of the dynamic symbol table.
 462   void
 463   assign_local_dynsym_offsets(const Input_objects*);
 464
 465   // Finish the .dynamic section and PT_DYNAMIC segment.
 466   void
 467   finish_dynamic_section(const Input_objects*, const Symbol_table*);
 468
 469   // Create the .interp section and PT_INTERP segment.
 470   void
 471   create_interp(const Target* target);
 472
 473   // Create the version sections.
 474   void
 475   create_version_sections(const Versions*,
 476                           const Symbol_table*,
 477                           unsigned int local_symcount,
 478                           const std::vector<Symbol*>& dynamic_symbols,
 479                           const Output_section* dynstr);
 480
 481   template<int size, bool big_endian>
 482   void
 483   sized_create_version_sections(const Versions* versions,
 484                                 const Symbol_table*,
 485                                 unsigned int local_symcount,
 486                                 const std::vector<Symbol*>& dynamic_symbols,
 487                                 const Output_section* dynstr);
 488
 489   // Return whether to include this section in the link.
 490   template<int size, bool big_endian>
 491   bool
 492   include_section(Sized_relobj<size, big_endian>* object, const char* name,
 493                   const elfcpp::Shdr<size, big_endian>&);
 494
 495   // Return the output section name to use given an input section
 496   // name.  Set *PLEN to the length of the name.  *PLEN must be
 497   // initialized to the length of NAME.
 498   static const char*
 499   output_section_name(const char* name, size_t* plen);
 500
 501   // Return the output section name to use for a linkonce section
 502   // name.  PLEN is as for output_section_name.
 503   static const char*
 504   linkonce_output_name(const char* name, size_t* plen);
 505
 506   // Return the number of allocated output sections.
 507   size_t
 508   allocated_output_section_count() const;
 509
 510   // Return the output section for NAME, TYPE and FLAGS.
 511   Output_section*
 512   get_output_section(const char* name, Stringpool::Key name_key,
 513                      elfcpp::Elf_Word type, elfcpp::Elf_Xword flags);
 514
 515   // Choose the output section for NAME in RELOBJ.
 516   Output_section*
 517   choose_output_section(const Relobj* relobj, const char* name,
 518                         elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
 519                         bool is_input_section);
 520
 521   // Create a new Output_section.
 522   Output_section*
 523   make_output_section(const char* name, elfcpp::Elf_Word type,
 524                       elfcpp::Elf_Xword flags);
 525
 526   // Attach a section to a segment.
 527   void
 528   attach_section_to_segment(Output_section*);
 529
 530   // Attach an allocated section to a segment.
 531   void
 532   attach_allocated_section_to_segment(Output_section*);
 533
 534   // Set the final file offsets of all the segments.
 535   off_t
 536   set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
 537
 538   // Set the file offsets of the sections when doing a relocatable
 539   // link.
 540   off_t
 541   set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
 542
 543   // Set the final file offsets of all the sections not associated
 544   // with a segment.  We set section offsets in three passes: the
 545   // first handles all allocated sections, the second sections that
 546   // require postprocessing, and the last the late-bound STRTAB
 547   // sections (probably only shstrtab, which is the one we care about
 548   // because it holds section names).
 549   enum Section_offset_pass
 550   {
 551     BEFORE_INPUT_SECTIONS_PASS,
 552     POSTPROCESSING_SECTIONS_PASS,
 553     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
 554   };
 555   off_t
 556   set_section_offsets(off_t, Section_offset_pass pass);
 557
 558   // Set the final section indexes of all the sections not associated
 559   // with a segment.  Returns the next unused index.
 560   unsigned int
 561   set_section_indexes(unsigned int pshndx);
 562
 563   // Set the section addresses when using a script.
 564   Output_segment*
 565   set_section_addresses_from_script(Symbol_table*);
 566
 567   // Return whether SEG1 comes before SEG2 in the output file.
 568   static bool
 569   segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
 570
 571   // A mapping used for group signatures.
 572   struct Kept_section
 573     {
 574       Kept_section()
 575         : object_(NULL), shndx_(0), group_(false)
 576       { }
 577       Kept_section(Relobj* object, unsigned int shndx, bool group)
 578         : object_(object), shndx_(shndx), group_(group)
 579       { }
 580       Relobj* object_;
 581       unsigned int shndx_;
 582       bool group_;
 583     };
 584   typedef Unordered_map<std::string, Kept_section> Signatures;
 585
 586   // Mapping from input section name/type/flags to output section.  We
 587   // use canonicalized strings here.
 588
 589   typedef std::pair<Stringpool::Key,
 590                     std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
 591
 592   struct Hash_key
 593   {
 594     size_t
 595     operator()(const Key& k) const;
 596   };
 597
 598   typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
 599
 600   // A comparison class for segments.
 601
 602   struct Compare_segments
 603   {
 604     bool
 605     operator()(const Output_segment* seg1, const Output_segment* seg2)
 606     { return Layout::segment_precedes(seg1, seg2); }
 607   };
 608
 609   // A reference to the options on the command line.
 610   const General_options& options_;
 611   // Information set by scripts or by command line options.
 612   Script_options* script_options_;
 613   // The output section names.
 614   Stringpool namepool_;
 615   // The output symbol names.
 616   Stringpool sympool_;
 617   // The dynamic strings, if needed.
 618   Stringpool dynpool_;
 619   // The list of group sections and linkonce sections which we have seen.
 620   Signatures signatures_;
 621   // The mapping from input section name/type/flags to output sections.
 622   Section_name_map section_name_map_;
 623   // The list of output segments.
 624   Segment_list segment_list_;
 625   // The list of output sections.
 626   Section_list section_list_;
 627   // The list of output sections which are not attached to any output
 628   // segment.
 629   Section_list unattached_section_list_;
 630   // Whether we have attached the sections to the segments.
 631   bool sections_are_attached_;
 632   // The list of unattached Output_data objects which require special
 633   // handling because they are not Output_sections.
 634   Data_list special_output_list_;
 635   // The section headers.
 636   Output_section_headers* section_headers_;
 637   // A pointer to the PT_TLS segment if there is one.
 638   Output_segment* tls_segment_;
 639   // A pointer to the PT_GNU_RELRO segment if there is one.
 640   Output_segment* relro_segment_;
 641   // The SHT_SYMTAB output section.
 642   Output_section* symtab_section_;
 643   // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
 644   Output_symtab_xindex* symtab_xindex_;
 645   // The SHT_DYNSYM output section if there is one.
 646   Output_section* dynsym_section_;
 647   // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
 648   Output_symtab_xindex* dynsym_xindex_;
 649   // The SHT_DYNAMIC output section if there is one.
 650   Output_section* dynamic_section_;
 651   // The dynamic data which goes into dynamic_section_.
 652   Output_data_dynamic* dynamic_data_;
 653   // The exception frame output section if there is one.
 654   Output_section* eh_frame_section_;
 655   // The exception frame data for eh_frame_section_.
 656   Eh_frame* eh_frame_data_;
 657   // Whether we have added eh_frame_data_ to the .eh_frame section.
 658   bool added_eh_frame_data_;
 659   // The exception frame header output section if there is one.
 660   Output_section* eh_frame_hdr_section_;
 661   // The space for the build ID checksum if there is one.
 662   Output_section_data* build_id_note_;
 663   // A list of group sections and their signatures.
 664   Group_signatures group_signatures_;
 665   // The size of the output file.
 666   off_t output_file_size_;
 667   // Whether we have seen an object file marked to require an
 668   // executable stack.
 669   bool input_requires_executable_stack_;
 670   // Whether we have seen at least one object file with an executable
 671   // stack marker.
 672   bool input_with_gnu_stack_note_;
 673   // Whether we have seen at least one object file without an
 674   // executable stack marker.
 675   bool input_without_gnu_stack_note_;
 676   // Whether we have seen an object file that uses the static TLS model.
 677   bool has_static_tls_;
 678   // Whether any sections require postprocessing.
 679   bool any_postprocessing_sections_;
 680 };
 681
 682 // This task handles writing out data in output sections which is not
 683 // part of an input section, or which requires special handling.  When
 684 // this is done, it unblocks both output_sections_blocker and
 685 // final_blocker.
 686
 687 class Write_sections_task : public Task
 688 {
 689  public:
 690   Write_sections_task(const Layout* layout, Output_file* of,
 691                       Task_token* output_sections_blocker,
 692                       Task_token* final_blocker)
 693     : layout_(layout), of_(of),
 694       output_sections_blocker_(output_sections_blocker),
 695       final_blocker_(final_blocker)
 696   { }
 697
 698   // The standard Task methods.
 699
 700   Task_token*
 701   is_runnable();
 702
 703   void
 704   locks(Task_locker*);
 705
 706   void
 707   run(Workqueue*);
 708
 709   std::string
 710   get_name() const
 711   { return "Write_sections_task"; }
 712
 713  private:
 714   class Write_sections_locker;
 715
 716   const Layout* layout_;
 717   Output_file* of_;
 718   Task_token* output_sections_blocker_;
 719   Task_token* final_blocker_;
 720 };
 721
 722 // This task handles writing out data which is not part of a section
 723 // or segment.
 724
 725 class Write_data_task : public Task
 726 {
 727  public:
 728   Write_data_task(const Layout* layout, const Symbol_table* symtab,
 729                   Output_file* of, Task_token* final_blocker)
 730     : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
 731   { }
 732
 733   // The standard Task methods.
 734
 735   Task_token*
 736   is_runnable();
 737
 738   void
 739   locks(Task_locker*);
 740
 741   void
 742   run(Workqueue*);
 743
 744   std::string
 745   get_name() const
 746   { return "Write_data_task"; }
 747
 748  private:
 749   const Layout* layout_;
 750   const Symbol_table* symtab_;
 751   Output_file* of_;
 752   Task_token* final_blocker_;
 753 };
 754
 755 // This task handles writing out the global symbols.
 756
 757 class Write_symbols_task : public Task
 758 {
 759  public:
 760   Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
 761                      const Input_objects* input_objects,
 762                      const Stringpool* sympool, const Stringpool* dynpool,
 763                      Output_file* of, Task_token* final_blocker)
 764     : layout_(layout), symtab_(symtab), input_objects_(input_objects),
 765       sympool_(sympool), dynpool_(dynpool), of_(of),
 766       final_blocker_(final_blocker)
 767   { }
 768
 769   // The standard Task methods.
 770
 771   Task_token*
 772   is_runnable();
 773
 774   void
 775   locks(Task_locker*);
 776
 777   void
 778   run(Workqueue*);
 779
 780   std::string
 781   get_name() const
 782   { return "Write_symbols_task"; }
 783
 784  private:
 785   const Layout* layout_;
 786   const Symbol_table* symtab_;
 787   const Input_objects* input_objects_;
 788   const Stringpool* sympool_;
 789   const Stringpool* dynpool_;
 790   Output_file* of_;
 791   Task_token* final_blocker_;
 792 };
 793
 794 // This task handles writing out data in output sections which can't
 795 // be written out until all the input sections have been handled.
 796 // This is for sections whose contents is based on the contents of
 797 // other output sections.
 798
 799 class Write_after_input_sections_task : public Task
 800 {
 801  public:
 802   Write_after_input_sections_task(Layout* layout, Output_file* of,
 803                                   Task_token* input_sections_blocker,
 804                                   Task_token* final_blocker)
 805     : layout_(layout), of_(of),
 806       input_sections_blocker_(input_sections_blocker),
 807       final_blocker_(final_blocker)
 808   { }
 809
 810   // The standard Task methods.
 811
 812   Task_token*
 813   is_runnable();
 814
 815   void
 816   locks(Task_locker*);
 817
 818   void
 819   run(Workqueue*);
 820
 821   std::string
 822   get_name() const
 823   { return "Write_after_input_sections_task"; }
 824
 825  private:
 826   Layout* layout_;
 827   Output_file* of_;
 828   Task_token* input_sections_blocker_;
 829   Task_token* final_blocker_;
 830 };
 831
 832 // This task function handles closing the file.
 833
 834 class Close_task_runner : public Task_function_runner
 835 {
 836  public:
 837   Close_task_runner(const General_options* options, const Layout* layout,
 838                     Output_file* of)
 839     : options_(options), layout_(layout), of_(of)
 840   { }
 841
 842   // Run the operation.
 843   void
 844   run(Workqueue*, const Task*);
 845
 846  private:
 847   const General_options* options_;
 848   const Layout* layout_;
 849   Output_file* of_;
 850 };
 851
 852 // A small helper function to align an address.
 853
 854 inline uint64_t
 855 align_address(uint64_t address, uint64_t addralign)
 856 {
 857   if (addralign != 0)
 858     address = (address + addralign - 1) &~ (addralign - 1);
 859   return address;
 860 }
 861
 862 } // End namespace gold.
 863
 864 #endif // !defined(GOLD_LAYOUT_H)