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