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