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 Mapfile;
  44 class Symbol_table;
  45 class Output_section_data;
  46 class Output_section;
  47 class Output_section_headers;
  48 class Output_segment;
  49 class Output_data;
  50 class Output_data_dynamic;
  51 class Output_symtab_xindex;
  52 class Output_reduced_debug_abbrev_section;
  53 class Output_reduced_debug_info_section;
  54 class Eh_frame;
  55 class Target;
  56
  57 // This task function handles mapping the input sections to output
  58 // sections and laying them out in memory.
  59
  60 class Layout_task_runner : public Task_function_runner
  61 {
  62  public:
  63   // OPTIONS is the command line options, INPUT_OBJECTS is the list of
  64   // input objects, SYMTAB is the symbol table, LAYOUT is the layout
  65   // object.
  66   Layout_task_runner(const General_options& options,
  67                      const Input_objects* input_objects,
  68                      Symbol_table* symtab,
  69                      Target* target,
  70                      Layout* layout,
  71                      Mapfile* mapfile)
  72     : options_(options), input_objects_(input_objects), symtab_(symtab),
  73       target_(target), layout_(layout), mapfile_(mapfile)
  74   { }
  75
  76   // Run the operation.
  77   void
  78   run(Workqueue*, const Task*);
  79
  80  private:
  81   Layout_task_runner(const Layout_task_runner&);
  82   Layout_task_runner& operator=(const Layout_task_runner&);
  83
  84   const General_options& options_;
  85   const Input_objects* input_objects_;
  86   Symbol_table* symtab_;
  87   Target* target_;
  88   Layout* layout_;
  89   Mapfile* mapfile_;
  90 };
  91
  92 // This class handles the details of laying out input sections.
  93
  94 class Layout
  95 {
  96  public:
  97   Layout(const General_options& options, Script_options*);
  98
  99   // Given an input section SHNDX, named NAME, with data in SHDR, from
 100   // the object file OBJECT, return the output section where this
 101   // input section should go.  RELOC_SHNDX is the index of a
 102   // relocation section which applies to this section, or 0 if none,
 103   // or -1U if more than one.  RELOC_TYPE is the type of the
 104   // relocation section if there is one.  Set *OFFSET to the offset
 105   // within the output section.
 106   template<int size, bool big_endian>
 107   Output_section*
 108   layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
 109          const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 110          unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
 111
 112   // Layout an input reloc section when doing a relocatable link.  The
 113   // section is RELOC_SHNDX in OBJECT, with data in SHDR.
 114   // DATA_SECTION is the reloc section to which it refers.  RR is the
 115   // relocatable information.
 116   template<int size, bool big_endian>
 117   Output_section*
 118   layout_reloc(Sized_relobj<size, big_endian>* object,
 119                unsigned int reloc_shndx,
 120                const elfcpp::Shdr<size, big_endian>& shdr,
 121                Output_section* data_section,
 122                Relocatable_relocs* rr);
 123
 124   // Layout a group section when doing a relocatable link.
 125   template<int size, bool big_endian>
 126   void
 127   layout_group(Symbol_table* symtab,
 128                Sized_relobj<size, big_endian>* object,
 129                unsigned int group_shndx,
 130                const char* group_section_name,
 131                const char* signature,
 132                const elfcpp::Shdr<size, big_endian>& shdr,
 133                elfcpp::Elf_Word flags,
 134                std::vector<unsigned int>* shndxes);
 135
 136   // Like layout, only for exception frame sections.  OBJECT is an
 137   // object file.  SYMBOLS is the contents of the symbol table
 138   // section, with size SYMBOLS_SIZE.  SYMBOL_NAMES is the contents of
 139   // the symbol name section, with size SYMBOL_NAMES_SIZE.  SHNDX is a
 140   // .eh_frame section in OBJECT.  SHDR is the section header.
 141   // RELOC_SHNDX is the index of a relocation section which applies to
 142   // this section, or 0 if none, or -1U if more than one.  RELOC_TYPE
 143   // is the type of the relocation section if there is one.  This
 144   // returns the output section, and sets *OFFSET to the offset.
 145   template<int size, bool big_endian>
 146   Output_section*
 147   layout_eh_frame(Sized_relobj<size, big_endian>* object,
 148                   const unsigned char* symbols,
 149                   off_t symbols_size,
 150                   const unsigned char* symbol_names,
 151                   off_t symbol_names_size,
 152                   unsigned int shndx,
 153                   const elfcpp::Shdr<size, big_endian>& shdr,
 154                   unsigned int reloc_shndx, unsigned int reloc_type,
 155                   off_t* offset);
 156
 157   // Handle a GNU stack note.  This is called once per input object
 158   // file.  SEEN_GNU_STACK is true if the object file has a
 159   // .note.GNU-stack section.  GNU_STACK_FLAGS is the section flags
 160   // from that section if there was one.
 161   void
 162   layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
 163
 164   // Add an Output_section_data to the layout.  This is used for
 165   // special sections like the GOT section.
 166   Output_section*
 167   add_output_section_data(const char* name, elfcpp::Elf_Word type,
 168                           elfcpp::Elf_Xword flags,
 169                           Output_section_data*);
 170
 171   // Create dynamic sections if necessary.
 172   void
 173   create_initial_dynamic_sections(Symbol_table*);
 174
 175   // Define __start and __stop symbols for output sections.
 176   void
 177   define_section_symbols(Symbol_table*);
 178
 179   // Create sections for linker scripts.
 180   void
 181   create_script_sections()
 182   { this->script_options_->create_script_sections(this); }
 183
 184   // Define symbols from any linker script.
 185   void
 186   define_script_symbols(Symbol_table* symtab)
 187   { this->script_options_->add_symbols_to_table(symtab); }
 188
 189   // Define symbols for group signatures.
 190   void
 191   define_group_signatures(Symbol_table*);
 192
 193   // Return the Stringpool used for symbol names.
 194   const Stringpool*
 195   sympool() const
 196   { return &this->sympool_; }
 197
 198   // Return the Stringpool used for dynamic symbol names and dynamic
 199   // tags.
 200   const Stringpool*
 201   dynpool() const
 202   { return &this->dynpool_; }
 203
 204   // Return the symtab_xindex section used to hold large section
 205   // indexes for the normal symbol table.
 206   Output_symtab_xindex*
 207   symtab_xindex() const
 208   { return this->symtab_xindex_; }
 209
 210   // Return the dynsym_xindex section used to hold large section
 211   // indexes for the dynamic symbol table.
 212   Output_symtab_xindex*
 213   dynsym_xindex() const
 214   { return this->dynsym_xindex_; }
 215
 216   // Return whether a section is a .gnu.linkonce section, given the
 217   // section name.
 218   static inline bool
 219   is_linkonce(const char* name)
 220   { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
 221
 222   // Return true if a section is a debugging section.
 223   static inline bool
 224   is_debug_info_section(const char* name)
 225   {
 226     // Debugging sections can only be recognized by name.
 227     return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
 228             || strncmp(name, ".gnu.linkonce.wi.",
 229                        sizeof(".gnu.linkonce.wi.") - 1) == 0
 230             || strncmp(name, ".line", sizeof(".line") - 1) == 0
 231             || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
 232   }
 233
 234   // Record the signature of a comdat section, and return whether to
 235   // include it in the link.  The GROUP parameter is true for a
 236   // section group signature, false for a signature derived from a
 237   // .gnu.linkonce section.
 238   bool
 239   add_comdat(Relobj*, unsigned int, const std::string&, bool group);
 240
 241   // Find the given comdat signature, and return the object and section
 242   // index of the kept group.
 243   Relobj*
 244   find_kept_object(const std::string&, unsigned int*) const;
 245
 246   // Finalize the layout after all the input sections have been added.
 247   off_t
 248   finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
 249
 250   // Return whether any sections require postprocessing.
 251   bool
 252   any_postprocessing_sections() const
 253   { return this->any_postprocessing_sections_; }
 254
 255   // Return the size of the output file.
 256   off_t
 257   output_file_size() const
 258   { return this->output_file_size_; }
 259
 260   // Return the TLS segment.  This will return NULL if there isn't
 261   // one.
 262   Output_segment*
 263   tls_segment() const
 264   { return this->tls_segment_; }
 265
 266   // Return the normal symbol table.
 267   Output_section*
 268   symtab_section() const
 269   {
 270     gold_assert(this->symtab_section_ != NULL);
 271     return this->symtab_section_;
 272   }
 273
 274   // Return the dynamic symbol table.
 275   Output_section*
 276   dynsym_section() const
 277   {
 278     gold_assert(this->dynsym_section_ != NULL);
 279     return this->dynsym_section_;
 280   }
 281
 282   // Return the dynamic tags.
 283   Output_data_dynamic*
 284   dynamic_data() const
 285   { return this->dynamic_data_; }
 286
 287   // Write out the output sections.
 288   void
 289   write_output_sections(Output_file* of) const;
 290
 291   // Write out data not associated with an input file or the symbol
 292   // table.
 293   void
 294   write_data(const Symbol_table*, Output_file*) const;
 295
 296   // Write out output sections which can not be written until all the
 297   // input sections are complete.
 298   void
 299   write_sections_after_input_sections(Output_file* of);
 300
 301   // Return an output section named NAME, or NULL if there is none.
 302   Output_section*
 303   find_output_section(const char* name) const;
 304
 305   // Return an output segment of type TYPE, with segment flags SET set
 306   // and segment flags CLEAR clear.  Return NULL if there is none.
 307   Output_segment*
 308   find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
 309                       elfcpp::Elf_Word clear) const;
 310
 311   // Return the number of segments we expect to produce.
 312   size_t
 313   expected_segment_count() const;
 314
 315   // Set a flag to indicate that an object file uses the static TLS model.
 316   void
 317   set_has_static_tls()
 318   { this->has_static_tls_ = true; }
 319
 320   // Return true if any object file uses the static TLS model.
 321   bool
 322   has_static_tls() const
 323   { return this->has_static_tls_; }
 324
 325   // Return the options which may be set by a linker script.
 326   Script_options*
 327   script_options()
 328   { return this->script_options_; }
 329
 330   const Script_options*
 331   script_options() const
 332   { return this->script_options_; }
 333
 334   // Compute and write out the build ID if needed.
 335   void
 336   write_build_id(Output_file*) const;
 337
 338   // Rewrite output file in binary format.
 339   void
 340   write_binary(Output_file* in) const;
 341
 342   // Print output sections to the map file.
 343   void
 344   print_to_mapfile(Mapfile*) const;
 345
 346   // Dump statistical information to stderr.
 347   void
 348   print_stats() const;
 349
 350   // A list of segments.
 351
 352   typedef std::vector<Output_segment*> Segment_list;
 353
 354   // A list of sections.
 355
 356   typedef std::vector<Output_section*> Section_list;
 357
 358   // The list of information to write out which is not attached to
 359   // either a section or a segment.
 360   typedef std::vector<Output_data*> Data_list;
 361
 362   // Store the allocated sections into the section list.  This is used
 363   // by the linker script code.
 364   void
 365   get_allocated_sections(Section_list*) const;
 366
 367   // Make a section for a linker script to hold data.
 368   Output_section*
 369   make_output_section_for_script(const char* name);
 370
 371   // Make a segment.  This is used by the linker script code.
 372   Output_segment*
 373   make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
 374
 375   // Return the number of segments.
 376   size_t
 377   segment_count() const
 378   { return this->segment_list_.size(); }
 379
 380   // Map from section flags to segment flags.
 381   static elfcpp::Elf_Word
 382   section_flags_to_segment(elfcpp::Elf_Xword flags);
 383
 384   // Attach sections to segments.
 385   void
 386   attach_sections_to_segments();
 387
 388  private:
 389   Layout(const Layout&);
 390   Layout& operator=(const Layout&);
 391
 392   // Mapping from .gnu.linkonce section names to output section names.
 393   struct Linkonce_mapping
 394   {
 395     const char* from;
 396     int fromlen;
 397     const char* to;
 398     int tolen;
 399   };
 400   static const Linkonce_mapping linkonce_mapping[];
 401   static const int linkonce_mapping_count;
 402
 403   // During a relocatable link, a list of group sections and
 404   // signatures.
 405   struct Group_signature
 406   {
 407     // The group section.
 408     Output_section* section;
 409     // The signature.
 410     const char* signature;
 411
 412     Group_signature()
 413       : section(NULL), signature(NULL)
 414     { }
 415
 416     Group_signature(Output_section* sectiona, const char* signaturea)
 417       : section(sectiona), signature(signaturea)
 418     { }
 419   };
 420   typedef std::vector<Group_signature> Group_signatures;
 421
 422   // Create a .note section, filling in the header.
 423   Output_section*
 424   create_note(const char* name, int note_type, size_t descsz,
 425               bool allocate, size_t* trailing_padding);
 426
 427   // Create a .note section for gold.
 428   void
 429   create_gold_note();
 430
 431   // Record whether the stack must be executable.
 432   void
 433   create_executable_stack_info(const Target*);
 434
 435   // Create a build ID note if needed.
 436   void
 437   create_build_id();
 438
 439   // Find the first read-only PT_LOAD segment, creating one if
 440   // necessary.
 441   Output_segment*
 442   find_first_load_seg();
 443
 444   // Count the local symbols in the regular symbol table and the dynamic
 445   // symbol table, and build the respective string pools.
 446   void
 447   count_local_symbols(const Task*, const Input_objects*);
 448
 449   // Create the output sections for the symbol table.
 450   void
 451   create_symtab_sections(const Input_objects*, Symbol_table*,
 452                          unsigned int, off_t*);
 453
 454   // Create the .shstrtab section.
 455   Output_section*
 456   create_shstrtab();
 457
 458   // Create the section header table.
 459   void
 460   create_shdrs(const Output_section* shstrtab_section, off_t*);
 461
 462   // Create the dynamic symbol table.
 463   void
 464   create_dynamic_symtab(const Input_objects*, Symbol_table*,
 465                         Output_section** pdynstr,
 466                         unsigned int* plocal_dynamic_count,
 467                         std::vector<Symbol*>* pdynamic_symbols,
 468                         Versions* versions);
 469
 470   // Assign offsets to each local portion of the dynamic symbol table.
 471   void
 472   assign_local_dynsym_offsets(const Input_objects*);
 473
 474   // Finish the .dynamic section and PT_DYNAMIC segment.
 475   void
 476   finish_dynamic_section(const Input_objects*, const Symbol_table*);
 477
 478   // Create the .interp section and PT_INTERP segment.
 479   void
 480   create_interp(const Target* target);
 481
 482   // Create the version sections.
 483   void
 484   create_version_sections(const Versions*,
 485                           const Symbol_table*,
 486                           unsigned int local_symcount,
 487                           const std::vector<Symbol*>& dynamic_symbols,
 488                           const Output_section* dynstr);
 489
 490   template<int size, bool big_endian>
 491   void
 492   sized_create_version_sections(const Versions* versions,
 493                                 const Symbol_table*,
 494                                 unsigned int local_symcount,
 495                                 const std::vector<Symbol*>& dynamic_symbols,
 496                                 const Output_section* dynstr);
 497
 498   // Return whether to include this section in the link.
 499   template<int size, bool big_endian>
 500   bool
 501   include_section(Sized_relobj<size, big_endian>* object, const char* name,
 502                   const elfcpp::Shdr<size, big_endian>&);
 503
 504   // Return the output section name to use given an input section
 505   // name.  Set *PLEN to the length of the name.  *PLEN must be
 506   // initialized to the length of NAME.
 507   static const char*
 508   output_section_name(const char* name, size_t* plen);
 509
 510   // Return the output section name to use for a linkonce section
 511   // name.  PLEN is as for output_section_name.
 512   static const char*
 513   linkonce_output_name(const char* name, size_t* plen);
 514
 515   // Return the number of allocated output sections.
 516   size_t
 517   allocated_output_section_count() const;
 518
 519   // Return the output section for NAME, TYPE and FLAGS.
 520   Output_section*
 521   get_output_section(const char* name, Stringpool::Key name_key,
 522                      elfcpp::Elf_Word type, elfcpp::Elf_Xword flags);
 523
 524   // Choose the output section for NAME in RELOBJ.
 525   Output_section*
 526   choose_output_section(const Relobj* relobj, const char* name,
 527                         elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
 528                         bool is_input_section);
 529
 530   // Create a new Output_section.
 531   Output_section*
 532   make_output_section(const char* name, elfcpp::Elf_Word type,
 533                       elfcpp::Elf_Xword flags);
 534
 535   // Attach a section to a segment.
 536   void
 537   attach_section_to_segment(Output_section*);
 538
 539   // Attach an allocated section to a segment.
 540   void
 541   attach_allocated_section_to_segment(Output_section*);
 542
 543   // Set the final file offsets of all the segments.
 544   off_t
 545   set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
 546
 547   // Set the file offsets of the sections when doing a relocatable
 548   // link.
 549   off_t
 550   set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
 551
 552   // Set the final file offsets of all the sections not associated
 553   // with a segment.  We set section offsets in three passes: the
 554   // first handles all allocated sections, the second sections that
 555   // require postprocessing, and the last the late-bound STRTAB
 556   // sections (probably only shstrtab, which is the one we care about
 557   // because it holds section names).
 558   enum Section_offset_pass
 559   {
 560     BEFORE_INPUT_SECTIONS_PASS,
 561     POSTPROCESSING_SECTIONS_PASS,
 562     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
 563   };
 564   off_t
 565   set_section_offsets(off_t, Section_offset_pass pass);
 566
 567   // Set the final section indexes of all the sections not associated
 568   // with a segment.  Returns the next unused index.
 569   unsigned int
 570   set_section_indexes(unsigned int pshndx);
 571
 572   // Set the section addresses when using a script.
 573   Output_segment*
 574   set_section_addresses_from_script(Symbol_table*);
 575
 576   // Return whether SEG1 comes before SEG2 in the output file.
 577   static bool
 578   segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
 579
 580   // A mapping used for group signatures.
 581   struct Kept_section
 582     {
 583       Kept_section()
 584         : object_(NULL), shndx_(0), group_(false)
 585       { }
 586       Kept_section(Relobj* object, unsigned int shndx, bool group)
 587         : object_(object), shndx_(shndx), group_(group)
 588       { }
 589       Relobj* object_;
 590       unsigned int shndx_;
 591       bool group_;
 592     };
 593   typedef Unordered_map<std::string, Kept_section> Signatures;
 594
 595   // Mapping from input section name/type/flags to output section.  We
 596   // use canonicalized strings here.
 597
 598   typedef std::pair<Stringpool::Key,
 599                     std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
 600
 601   struct Hash_key
 602   {
 603     size_t
 604     operator()(const Key& k) const;
 605   };
 606
 607   typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
 608
 609   // A comparison class for segments.
 610
 611   struct Compare_segments
 612   {
 613     bool
 614     operator()(const Output_segment* seg1, const Output_segment* seg2)
 615     { return Layout::segment_precedes(seg1, seg2); }
 616   };
 617
 618   // A reference to the options on the command line.
 619   const General_options& options_;
 620   // Information set by scripts or by command line options.
 621   Script_options* script_options_;
 622   // The output section names.
 623   Stringpool namepool_;
 624   // The output symbol names.
 625   Stringpool sympool_;
 626   // The dynamic strings, if needed.
 627   Stringpool dynpool_;
 628   // The list of group sections and linkonce sections which we have seen.
 629   Signatures signatures_;
 630   // The mapping from input section name/type/flags to output sections.
 631   Section_name_map section_name_map_;
 632   // The list of output segments.
 633   Segment_list segment_list_;
 634   // The list of output sections.
 635   Section_list section_list_;
 636   // The list of output sections which are not attached to any output
 637   // segment.
 638   Section_list unattached_section_list_;
 639   // Whether we have attached the sections to the segments.
 640   bool sections_are_attached_;
 641   // The list of unattached Output_data objects which require special
 642   // handling because they are not Output_sections.
 643   Data_list special_output_list_;
 644   // The section headers.
 645   Output_section_headers* section_headers_;
 646   // A pointer to the PT_TLS segment if there is one.
 647   Output_segment* tls_segment_;
 648   // A pointer to the PT_GNU_RELRO segment if there is one.
 649   Output_segment* relro_segment_;
 650   // The SHT_SYMTAB output section.
 651   Output_section* symtab_section_;
 652   // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
 653   Output_symtab_xindex* symtab_xindex_;
 654   // The SHT_DYNSYM output section if there is one.
 655   Output_section* dynsym_section_;
 656   // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
 657   Output_symtab_xindex* dynsym_xindex_;
 658   // The SHT_DYNAMIC output section if there is one.
 659   Output_section* dynamic_section_;
 660   // The dynamic data which goes into dynamic_section_.
 661   Output_data_dynamic* dynamic_data_;
 662   // The exception frame output section if there is one.
 663   Output_section* eh_frame_section_;
 664   // The exception frame data for eh_frame_section_.
 665   Eh_frame* eh_frame_data_;
 666   // Whether we have added eh_frame_data_ to the .eh_frame section.
 667   bool added_eh_frame_data_;
 668   // The exception frame header output section if there is one.
 669   Output_section* eh_frame_hdr_section_;
 670   // The space for the build ID checksum if there is one.
 671   Output_section_data* build_id_note_;
 672   // The output section containing dwarf abbreviations
 673   Output_reduced_debug_abbrev_section* debug_abbrev_;
 674   // The output section containing the dwarf debug info tree
 675   Output_reduced_debug_info_section* debug_info_;
 676   // A list of group sections and their signatures.
 677   Group_signatures group_signatures_;
 678   // The size of the output file.
 679   off_t output_file_size_;
 680   // Whether we have seen an object file marked to require an
 681   // executable stack.
 682   bool input_requires_executable_stack_;
 683   // Whether we have seen at least one object file with an executable
 684   // stack marker.
 685   bool input_with_gnu_stack_note_;
 686   // Whether we have seen at least one object file without an
 687   // executable stack marker.
 688   bool input_without_gnu_stack_note_;
 689   // Whether we have seen an object file that uses the static TLS model.
 690   bool has_static_tls_;
 691   // Whether any sections require postprocessing.
 692   bool any_postprocessing_sections_;
 693 };
 694
 695 // This task handles writing out data in output sections which is not
 696 // part of an input section, or which requires special handling.  When
 697 // this is done, it unblocks both output_sections_blocker and
 698 // final_blocker.
 699
 700 class Write_sections_task : public Task
 701 {
 702  public:
 703   Write_sections_task(const Layout* layout, Output_file* of,
 704                       Task_token* output_sections_blocker,
 705                       Task_token* final_blocker)
 706     : layout_(layout), of_(of),
 707       output_sections_blocker_(output_sections_blocker),
 708       final_blocker_(final_blocker)
 709   { }
 710
 711   // The standard Task methods.
 712
 713   Task_token*
 714   is_runnable();
 715
 716   void
 717   locks(Task_locker*);
 718
 719   void
 720   run(Workqueue*);
 721
 722   std::string
 723   get_name() const
 724   { return "Write_sections_task"; }
 725
 726  private:
 727   class Write_sections_locker;
 728
 729   const Layout* layout_;
 730   Output_file* of_;
 731   Task_token* output_sections_blocker_;
 732   Task_token* final_blocker_;
 733 };
 734
 735 // This task handles writing out data which is not part of a section
 736 // or segment.
 737
 738 class Write_data_task : public Task
 739 {
 740  public:
 741   Write_data_task(const Layout* layout, const Symbol_table* symtab,
 742                   Output_file* of, Task_token* final_blocker)
 743     : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
 744   { }
 745
 746   // The standard Task methods.
 747
 748   Task_token*
 749   is_runnable();
 750
 751   void
 752   locks(Task_locker*);
 753
 754   void
 755   run(Workqueue*);
 756
 757   std::string
 758   get_name() const
 759   { return "Write_data_task"; }
 760
 761  private:
 762   const Layout* layout_;
 763   const Symbol_table* symtab_;
 764   Output_file* of_;
 765   Task_token* final_blocker_;
 766 };
 767
 768 // This task handles writing out the global symbols.
 769
 770 class Write_symbols_task : public Task
 771 {
 772  public:
 773   Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
 774                      const Input_objects* input_objects,
 775                      const Stringpool* sympool, const Stringpool* dynpool,
 776                      Output_file* of, Task_token* final_blocker)
 777     : layout_(layout), symtab_(symtab), input_objects_(input_objects),
 778       sympool_(sympool), dynpool_(dynpool), of_(of),
 779       final_blocker_(final_blocker)
 780   { }
 781
 782   // The standard Task methods.
 783
 784   Task_token*
 785   is_runnable();
 786
 787   void
 788   locks(Task_locker*);
 789
 790   void
 791   run(Workqueue*);
 792
 793   std::string
 794   get_name() const
 795   { return "Write_symbols_task"; }
 796
 797  private:
 798   const Layout* layout_;
 799   const Symbol_table* symtab_;
 800   const Input_objects* input_objects_;
 801   const Stringpool* sympool_;
 802   const Stringpool* dynpool_;
 803   Output_file* of_;
 804   Task_token* final_blocker_;
 805 };
 806
 807 // This task handles writing out data in output sections which can't
 808 // be written out until all the input sections have been handled.
 809 // This is for sections whose contents is based on the contents of
 810 // other output sections.
 811
 812 class Write_after_input_sections_task : public Task
 813 {
 814  public:
 815   Write_after_input_sections_task(Layout* layout, Output_file* of,
 816                                   Task_token* input_sections_blocker,
 817                                   Task_token* final_blocker)
 818     : layout_(layout), of_(of),
 819       input_sections_blocker_(input_sections_blocker),
 820       final_blocker_(final_blocker)
 821   { }
 822
 823   // The standard Task methods.
 824
 825   Task_token*
 826   is_runnable();
 827
 828   void
 829   locks(Task_locker*);
 830
 831   void
 832   run(Workqueue*);
 833
 834   std::string
 835   get_name() const
 836   { return "Write_after_input_sections_task"; }
 837
 838  private:
 839   Layout* layout_;
 840   Output_file* of_;
 841   Task_token* input_sections_blocker_;
 842   Task_token* final_blocker_;
 843 };
 844
 845 // This task function handles closing the file.
 846
 847 class Close_task_runner : public Task_function_runner
 848 {
 849  public:
 850   Close_task_runner(const General_options* options, const Layout* layout,
 851                     Output_file* of)
 852     : options_(options), layout_(layout), of_(of)
 853   { }
 854
 855   // Run the operation.
 856   void
 857   run(Workqueue*, const Task*);
 858
 859  private:
 860   const General_options* options_;
 861   const Layout* layout_;
 862   Output_file* of_;
 863 };
 864
 865 // A small helper function to align an address.
 866
 867 inline uint64_t
 868 align_address(uint64_t address, uint64_t addralign)
 869 {
 870   if (addralign != 0)
 871     address = (address + addralign - 1) &~ (addralign - 1);
 872   return address;
 873 }
 874
 875 } // End namespace gold.
 876
 877 #endif // !defined(GOLD_LAYOUT_H)