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