gold/layout.h

   1 // layout.h -- lay out output file sections for gold  -*- C++ -*-
   2
   3 // Copyright 2006, 2007, 2008, 2009 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 Incremental_inputs;
  43 class Input_objects;
  44 class Mapfile;
  45 class Symbol_table;
  46 class Output_section_data;
  47 class Output_section;
  48 class Output_section_headers;
  49 class Output_segment;
  50 class Output_data;
  51 class Output_data_dynamic;
  52 class Output_symtab_xindex;
  53 class Output_reduced_debug_abbrev_section;
  54 class Output_reduced_debug_info_section;
  55 class Eh_frame;
  56 class Target;
  57
  58 // This task function handles mapping the input sections to output
  59 // sections and laying them out in memory.
  60
  61 class Layout_task_runner : public Task_function_runner
  62 {
  63  public:
  64   // OPTIONS is the command line options, INPUT_OBJECTS is the list of
  65   // input objects, SYMTAB is the symbol table, LAYOUT is the layout
  66   // object.
  67   Layout_task_runner(const General_options& options,
  68                      const Input_objects* input_objects,
  69                      Symbol_table* symtab,
  70                      Target* target,
  71                      Layout* layout,
  72                      Mapfile* mapfile)
  73     : options_(options), input_objects_(input_objects), symtab_(symtab),
  74       target_(target), layout_(layout), mapfile_(mapfile)
  75   { }
  76
  77   // Run the operation.
  78   void
  79   run(Workqueue*, const Task*);
  80
  81  private:
  82   Layout_task_runner(const Layout_task_runner&);
  83   Layout_task_runner& operator=(const Layout_task_runner&);
  84
  85   const General_options& options_;
  86   const Input_objects* input_objects_;
  87   Symbol_table* symtab_;
  88   Target* target_;
  89   Layout* layout_;
  90   Mapfile* mapfile_;
  91 };
  92
  93 // This struct holds information about the comdat or .gnu.linkonce
  94 // that will be kept.
  95
  96 struct Kept_section
  97 {
  98   Kept_section()
  99     : object(NULL), shndx(0), is_group(false), group_sections(NULL)
 100   { }
 101   Kept_section(Relobj* a_object, unsigned int a_shndx, bool a_is_group)
 102     : object(a_object), shndx(a_shndx), is_group(a_is_group),
 103       group_sections(NULL)
 104   { }
 105
 106   typedef Unordered_map<std::string, unsigned int> Comdat_group;
 107
 108   // The object containing the comdat or .gnu.linkonce.
 109   Relobj* object;
 110   // Index to the group section for comdats and the section itself for
 111   // .gnu.linkonce.
 112   unsigned int shndx;
 113   // The Kept_sections are values of a mapping, that maps names to
 114   // them.  This field is true if this struct is associated with the
 115   // name of a comdat or .gnu.linkonce, false if it is associated with
 116   // the name of a symbol obtained from the .gnu.linkonce.* name
 117   // through some heuristics.
 118   bool is_group;
 119   // For comdats, a map from names of the sections in the group to
 120   // indexes in OBJECT_.  NULL for .gnu.linkonce.
 121   Comdat_group* group_sections;
 122 };
 123
 124 // This class handles the details of laying out input sections.
 125
 126 class Layout
 127 {
 128  public:
 129   Layout(int number_of_input_files, Script_options*);
 130
 131   // Given an input section SHNDX, named NAME, with data in SHDR, from
 132   // the object file OBJECT, return the output section where this
 133   // input section should go.  RELOC_SHNDX is the index of a
 134   // relocation section which applies to this section, or 0 if none,
 135   // or -1U if more than one.  RELOC_TYPE is the type of the
 136   // relocation section if there is one.  Set *OFFSET to the offset
 137   // within the output section.
 138   template<int size, bool big_endian>
 139   Output_section*
 140   layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
 141          const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 142          unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
 143
 144   // Layout an input reloc section when doing a relocatable link.  The
 145   // section is RELOC_SHNDX in OBJECT, with data in SHDR.
 146   // DATA_SECTION is the reloc section to which it refers.  RR is the
 147   // relocatable information.
 148   template<int size, bool big_endian>
 149   Output_section*
 150   layout_reloc(Sized_relobj<size, big_endian>* object,
 151                unsigned int reloc_shndx,
 152                const elfcpp::Shdr<size, big_endian>& shdr,
 153                Output_section* data_section,
 154                Relocatable_relocs* rr);
 155
 156   // Layout a group section when doing a relocatable link.
 157   template<int size, bool big_endian>
 158   void
 159   layout_group(Symbol_table* symtab,
 160                Sized_relobj<size, big_endian>* object,
 161                unsigned int group_shndx,
 162                const char* group_section_name,
 163                const char* signature,
 164                const elfcpp::Shdr<size, big_endian>& shdr,
 165                elfcpp::Elf_Word flags,
 166                std::vector<unsigned int>* shndxes);
 167
 168   // Like layout, only for exception frame sections.  OBJECT is an
 169   // object file.  SYMBOLS is the contents of the symbol table
 170   // section, with size SYMBOLS_SIZE.  SYMBOL_NAMES is the contents of
 171   // the symbol name section, with size SYMBOL_NAMES_SIZE.  SHNDX is a
 172   // .eh_frame section in OBJECT.  SHDR is the section header.
 173   // RELOC_SHNDX is the index of a relocation section which applies to
 174   // this section, or 0 if none, or -1U if more than one.  RELOC_TYPE
 175   // is the type of the relocation section if there is one.  This
 176   // returns the output section, and sets *OFFSET to the offset.
 177   template<int size, bool big_endian>
 178   Output_section*
 179   layout_eh_frame(Sized_relobj<size, big_endian>* object,
 180                   const unsigned char* symbols,
 181                   off_t symbols_size,
 182                   const unsigned char* symbol_names,
 183                   off_t symbol_names_size,
 184                   unsigned int shndx,
 185                   const elfcpp::Shdr<size, big_endian>& shdr,
 186                   unsigned int reloc_shndx, unsigned int reloc_type,
 187                   off_t* offset);
 188
 189   // Handle a GNU stack note.  This is called once per input object
 190   // file.  SEEN_GNU_STACK is true if the object file has a
 191   // .note.GNU-stack section.  GNU_STACK_FLAGS is the section flags
 192   // from that section if there was one.
 193   void
 194   layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
 195
 196   // Add an Output_section_data to the layout.  This is used for
 197   // special sections like the GOT section.
 198   Output_section*
 199   add_output_section_data(const char* name, elfcpp::Elf_Word type,
 200                           elfcpp::Elf_Xword flags,
 201                           Output_section_data*);
 202
 203   // Create dynamic sections if necessary.
 204   void
 205   create_initial_dynamic_sections(Symbol_table*);
 206
 207   // Define __start and __stop symbols for output sections.
 208   void
 209   define_section_symbols(Symbol_table*);
 210
 211   // Create sections for linker scripts.
 212   void
 213   create_script_sections()
 214   { this->script_options_->create_script_sections(this); }
 215
 216   // Define symbols from any linker script.
 217   void
 218   define_script_symbols(Symbol_table* symtab)
 219   { this->script_options_->add_symbols_to_table(symtab); }
 220
 221   // Define symbols for group signatures.
 222   void
 223   define_group_signatures(Symbol_table*);
 224
 225   // Return the Stringpool used for symbol names.
 226   const Stringpool*
 227   sympool() const
 228   { return &this->sympool_; }
 229
 230   // Return the Stringpool used for dynamic symbol names and dynamic
 231   // tags.
 232   const Stringpool*
 233   dynpool() const
 234   { return &this->dynpool_; }
 235
 236   // Return the symtab_xindex section used to hold large section
 237   // indexes for the normal symbol table.
 238   Output_symtab_xindex*
 239   symtab_xindex() const
 240   { return this->symtab_xindex_; }
 241
 242   // Return the dynsym_xindex section used to hold large section
 243   // indexes for the dynamic symbol table.
 244   Output_symtab_xindex*
 245   dynsym_xindex() const
 246   { return this->dynsym_xindex_; }
 247
 248   // Return whether a section is a .gnu.linkonce section, given the
 249   // section name.
 250   static inline bool
 251   is_linkonce(const char* name)
 252   { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
 253
 254   // Return true if a section is a debugging section.
 255   static inline bool
 256   is_debug_info_section(const char* name)
 257   {
 258     // Debugging sections can only be recognized by name.
 259     return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
 260             || strncmp(name, ".gnu.linkonce.wi.",
 261                        sizeof(".gnu.linkonce.wi.") - 1) == 0
 262             || strncmp(name, ".line", sizeof(".line") - 1) == 0
 263             || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
 264   }
 265
 266   // Check if a comdat group or .gnu.linkonce section with the given
 267   // NAME is selected for the link.  If there is already a section,
 268   // *KEPT_SECTION is set to point to the signature and the function
 269   // returns false.  Otherwise, the CANDIDATE signature is recorded
 270   // for this NAME in the layout object, *KEPT_SECTION is set to the
 271   // internal copy and the function return false.  In some cases, with
 272   // CANDIDATE->GROUP_ being false, KEPT_SECTION can point back to
 273   // CANDIDATE.
 274   bool
 275   find_or_add_kept_section(const std::string& name,
 276                            Kept_section* candidate,
 277                            Kept_section** kept_section);
 278
 279   // Find the given comdat signature, and return the object and section
 280   // index of the kept group.
 281   Relobj*
 282   find_kept_object(const std::string&, unsigned int*) const;
 283
 284   // Finalize the layout after all the input sections have been added.
 285   off_t
 286   finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
 287
 288   // Return whether any sections require postprocessing.
 289   bool
 290   any_postprocessing_sections() const
 291   { return this->any_postprocessing_sections_; }
 292
 293   // Return the size of the output file.
 294   off_t
 295   output_file_size() const
 296   { return this->output_file_size_; }
 297
 298   // Return the TLS segment.  This will return NULL if there isn't
 299   // one.
 300   Output_segment*
 301   tls_segment() const
 302   { return this->tls_segment_; }
 303
 304   // Return the normal symbol table.
 305   Output_section*
 306   symtab_section() const
 307   {
 308     gold_assert(this->symtab_section_ != NULL);
 309     return this->symtab_section_;
 310   }
 311
 312   // Return the dynamic symbol table.
 313   Output_section*
 314   dynsym_section() const
 315   {
 316     gold_assert(this->dynsym_section_ != NULL);
 317     return this->dynsym_section_;
 318   }
 319
 320   // Return the dynamic tags.
 321   Output_data_dynamic*
 322   dynamic_data() const
 323   { return this->dynamic_data_; }
 324
 325   // Write out the output sections.
 326   void
 327   write_output_sections(Output_file* of) const;
 328
 329   // Write out data not associated with an input file or the symbol
 330   // table.
 331   void
 332   write_data(const Symbol_table*, Output_file*) const;
 333
 334   // Write out output sections which can not be written until all the
 335   // input sections are complete.
 336   void
 337   write_sections_after_input_sections(Output_file* of);
 338
 339   // Return an output section named NAME, or NULL if there is none.
 340   Output_section*
 341   find_output_section(const char* name) const;
 342
 343   // Return an output segment of type TYPE, with segment flags SET set
 344   // and segment flags CLEAR clear.  Return NULL if there is none.
 345   Output_segment*
 346   find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
 347                       elfcpp::Elf_Word clear) const;
 348
 349   // Return the number of segments we expect to produce.
 350   size_t
 351   expected_segment_count() const;
 352
 353   // Set a flag to indicate that an object file uses the static TLS model.
 354   void
 355   set_has_static_tls()
 356   { this->has_static_tls_ = true; }
 357
 358   // Return true if any object file uses the static TLS model.
 359   bool
 360   has_static_tls() const
 361   { return this->has_static_tls_; }
 362
 363   // Return the options which may be set by a linker script.
 364   Script_options*
 365   script_options()
 366   { return this->script_options_; }
 367
 368   const Script_options*
 369   script_options() const
 370   { return this->script_options_; }
 371
 372   // Return the object managing inputs in incremental build. NULL in
 373   // non-incremental builds.
 374   Incremental_inputs*
 375   incremental_inputs()
 376   { return this->incremental_inputs_; }
 377
 378   // Compute and write out the build ID if needed.
 379   void
 380   write_build_id(Output_file*) const;
 381
 382   // Rewrite output file in binary format.
 383   void
 384   write_binary(Output_file* in) const;
 385
 386   // Print output sections to the map file.
 387   void
 388   print_to_mapfile(Mapfile*) const;
 389
 390   // Dump statistical information to stderr.
 391   void
 392   print_stats() const;
 393
 394   // A list of segments.
 395
 396   typedef std::vector<Output_segment*> Segment_list;
 397
 398   // A list of sections.
 399
 400   typedef std::vector<Output_section*> Section_list;
 401
 402   // The list of information to write out which is not attached to
 403   // either a section or a segment.
 404   typedef std::vector<Output_data*> Data_list;
 405
 406   // Store the allocated sections into the section list.  This is used
 407   // by the linker script code.
 408   void
 409   get_allocated_sections(Section_list*) const;
 410
 411   // Make a section for a linker script to hold data.
 412   Output_section*
 413   make_output_section_for_script(const char* name);
 414
 415   // Make a segment.  This is used by the linker script code.
 416   Output_segment*
 417   make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
 418
 419   // Return the number of segments.
 420   size_t
 421   segment_count() const
 422   { return this->segment_list_.size(); }
 423
 424   // Map from section flags to segment flags.
 425   static elfcpp::Elf_Word
 426   section_flags_to_segment(elfcpp::Elf_Xword flags);
 427
 428   // Attach sections to segments.
 429   void
 430   attach_sections_to_segments();
 431
 432  private:
 433   Layout(const Layout&);
 434   Layout& operator=(const Layout&);
 435
 436   // Mapping from .gnu.linkonce section names to output section names.
 437   struct Linkonce_mapping
 438   {
 439     const char* from;
 440     int fromlen;
 441     const char* to;
 442     int tolen;
 443   };
 444   static const Linkonce_mapping linkonce_mapping[];
 445   static const int linkonce_mapping_count;
 446
 447   // During a relocatable link, a list of group sections and
 448   // signatures.
 449   struct Group_signature
 450   {
 451     // The group section.
 452     Output_section* section;
 453     // The signature.
 454     const char* signature;
 455
 456     Group_signature()
 457       : section(NULL), signature(NULL)
 458     { }
 459
 460     Group_signature(Output_section* sectiona, const char* signaturea)
 461       : section(sectiona), signature(signaturea)
 462     { }
 463   };
 464   typedef std::vector<Group_signature> Group_signatures;
 465
 466   // Create a note section, filling in the header.
 467   Output_section*
 468   create_note(const char* name, int note_type, const char *section_name,
 469               size_t descsz, bool allocate, size_t* trailing_padding);
 470
 471   // Create a note section for gold version.
 472   void
 473   create_gold_note();
 474
 475   // Record whether the stack must be executable.
 476   void
 477   create_executable_stack_info(const Target*);
 478
 479   // Create a build ID note if needed.
 480   void
 481   create_build_id();
 482
 483   // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
 484   // for the next run of incremental linking to check what has changed.
 485   void
 486   create_incremental_info_sections();
 487
 488   // Find the first read-only PT_LOAD segment, creating one if
 489   // necessary.
 490   Output_segment*
 491   find_first_load_seg();
 492
 493   // Count the local symbols in the regular symbol table and the dynamic
 494   // symbol table, and build the respective string pools.
 495   void
 496   count_local_symbols(const Task*, const Input_objects*);
 497
 498   // Create the output sections for the symbol table.
 499   void
 500   create_symtab_sections(const Input_objects*, Symbol_table*,
 501                          unsigned int, off_t*);
 502
 503   // Create the .shstrtab section.
 504   Output_section*
 505   create_shstrtab();
 506
 507   // Create the section header table.
 508   void
 509   create_shdrs(const Output_section* shstrtab_section, off_t*);
 510
 511   // Create the dynamic symbol table.
 512   void
 513   create_dynamic_symtab(const Input_objects*, Symbol_table*,
 514                         Output_section** pdynstr,
 515                         unsigned int* plocal_dynamic_count,
 516                         std::vector<Symbol*>* pdynamic_symbols,
 517                         Versions* versions);
 518
 519   // Assign offsets to each local portion of the dynamic symbol table.
 520   void
 521   assign_local_dynsym_offsets(const Input_objects*);
 522
 523   // Finish the .dynamic section and PT_DYNAMIC segment.
 524   void
 525   finish_dynamic_section(const Input_objects*, const Symbol_table*);
 526
 527   // Create the .interp section and PT_INTERP segment.
 528   void
 529   create_interp(const Target* target);
 530
 531   // Create the version sections.
 532   void
 533   create_version_sections(const Versions*,
 534                           const Symbol_table*,
 535                           unsigned int local_symcount,
 536                           const std::vector<Symbol*>& dynamic_symbols,
 537                           const Output_section* dynstr);
 538
 539   template<int size, bool big_endian>
 540   void
 541   sized_create_version_sections(const Versions* versions,
 542                                 const Symbol_table*,
 543                                 unsigned int local_symcount,
 544                                 const std::vector<Symbol*>& dynamic_symbols,
 545                                 const Output_section* dynstr);
 546
 547   // Return whether to include this section in the link.
 548   template<int size, bool big_endian>
 549   bool
 550   include_section(Sized_relobj<size, big_endian>* object, const char* name,
 551                   const elfcpp::Shdr<size, big_endian>&);
 552
 553   // Return the output section name to use given an input section
 554   // name.  Set *PLEN to the length of the name.  *PLEN must be
 555   // initialized to the length of NAME.
 556   static const char*
 557   output_section_name(const char* name, size_t* plen);
 558
 559   // Return the output section name to use for a linkonce section
 560   // name.  PLEN is as for output_section_name.
 561   static const char*
 562   linkonce_output_name(const char* name, size_t* plen);
 563
 564   // Return the number of allocated output sections.
 565   size_t
 566   allocated_output_section_count() const;
 567
 568   // Return the output section for NAME, TYPE and FLAGS.
 569   Output_section*
 570   get_output_section(const char* name, Stringpool::Key name_key,
 571                      elfcpp::Elf_Word type, elfcpp::Elf_Xword flags);
 572
 573   // Choose the output section for NAME in RELOBJ.
 574   Output_section*
 575   choose_output_section(const Relobj* relobj, const char* name,
 576                         elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
 577                         bool is_input_section);
 578
 579   // Create a new Output_section.
 580   Output_section*
 581   make_output_section(const char* name, elfcpp::Elf_Word type,
 582                       elfcpp::Elf_Xword flags);
 583
 584   // Attach a section to a segment.
 585   void
 586   attach_section_to_segment(Output_section*);
 587
 588   // Attach an allocated section to a segment.
 589   void
 590   attach_allocated_section_to_segment(Output_section*);
 591
 592   // Set the final file offsets of all the segments.
 593   off_t
 594   set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
 595
 596   // Set the file offsets of the sections when doing a relocatable
 597   // link.
 598   off_t
 599   set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
 600
 601   // Set the final file offsets of all the sections not associated
 602   // with a segment.  We set section offsets in three passes: the
 603   // first handles all allocated sections, the second sections that
 604   // require postprocessing, and the last the late-bound STRTAB
 605   // sections (probably only shstrtab, which is the one we care about
 606   // because it holds section names).
 607   enum Section_offset_pass
 608   {
 609     BEFORE_INPUT_SECTIONS_PASS,
 610     POSTPROCESSING_SECTIONS_PASS,
 611     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
 612   };
 613   off_t
 614   set_section_offsets(off_t, Section_offset_pass pass);
 615
 616   // Set the final section indexes of all the sections not associated
 617   // with a segment.  Returns the next unused index.
 618   unsigned int
 619   set_section_indexes(unsigned int pshndx);
 620
 621   // Set the section addresses when using a script.
 622   Output_segment*
 623   set_section_addresses_from_script(Symbol_table*);
 624
 625   // Return whether SEG1 comes before SEG2 in the output file.
 626   static bool
 627   segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
 628
 629   // A mapping used for kept comdats/.gnu.linkonce group signatures.
 630   typedef Unordered_map<std::string, Kept_section> Signatures;
 631
 632   // Mapping from input section name/type/flags to output section.  We
 633   // use canonicalized strings here.
 634
 635   typedef std::pair<Stringpool::Key,
 636                     std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
 637
 638   struct Hash_key
 639   {
 640     size_t
 641     operator()(const Key& k) const;
 642   };
 643
 644   typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
 645
 646   // A comparison class for segments.
 647
 648   struct Compare_segments
 649   {
 650     bool
 651     operator()(const Output_segment* seg1, const Output_segment* seg2)
 652     { return Layout::segment_precedes(seg1, seg2); }
 653   };
 654
 655   // The number of input files, for sizing tables.
 656   int number_of_input_files_;
 657   // Information set by scripts or by command line options.
 658   Script_options* script_options_;
 659   // The output section names.
 660   Stringpool namepool_;
 661   // The output symbol names.
 662   Stringpool sympool_;
 663   // The dynamic strings, if needed.
 664   Stringpool dynpool_;
 665   // The list of group sections and linkonce sections which we have seen.
 666   Signatures signatures_;
 667   // The mapping from input section name/type/flags to output sections.
 668   Section_name_map section_name_map_;
 669   // The list of output segments.
 670   Segment_list segment_list_;
 671   // The list of output sections.
 672   Section_list section_list_;
 673   // The list of output sections which are not attached to any output
 674   // segment.
 675   Section_list unattached_section_list_;
 676   // The list of unattached Output_data objects which require special
 677   // handling because they are not Output_sections.
 678   Data_list special_output_list_;
 679   // The section headers.
 680   Output_section_headers* section_headers_;
 681   // A pointer to the PT_TLS segment if there is one.
 682   Output_segment* tls_segment_;
 683   // A pointer to the PT_GNU_RELRO segment if there is one.
 684   Output_segment* relro_segment_;
 685   // The SHT_SYMTAB output section.
 686   Output_section* symtab_section_;
 687   // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
 688   Output_symtab_xindex* symtab_xindex_;
 689   // The SHT_DYNSYM output section if there is one.
 690   Output_section* dynsym_section_;
 691   // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
 692   Output_symtab_xindex* dynsym_xindex_;
 693   // The SHT_DYNAMIC output section if there is one.
 694   Output_section* dynamic_section_;
 695   // The dynamic data which goes into dynamic_section_.
 696   Output_data_dynamic* dynamic_data_;
 697   // The exception frame output section if there is one.
 698   Output_section* eh_frame_section_;
 699   // The exception frame data for eh_frame_section_.
 700   Eh_frame* eh_frame_data_;
 701   // Whether we have added eh_frame_data_ to the .eh_frame section.
 702   bool added_eh_frame_data_;
 703   // The exception frame header output section if there is one.
 704   Output_section* eh_frame_hdr_section_;
 705   // The space for the build ID checksum if there is one.
 706   Output_section_data* build_id_note_;
 707   // The output section containing dwarf abbreviations
 708   Output_reduced_debug_abbrev_section* debug_abbrev_;
 709   // The output section containing the dwarf debug info tree
 710   Output_reduced_debug_info_section* debug_info_;
 711   // A list of group sections and their signatures.
 712   Group_signatures group_signatures_;
 713   // The size of the output file.
 714   off_t output_file_size_;
 715   // Whether we have attached the sections to the segments.
 716   bool sections_are_attached_;
 717   // Whether we have seen an object file marked to require an
 718   // executable stack.
 719   bool input_requires_executable_stack_;
 720   // Whether we have seen at least one object file with an executable
 721   // stack marker.
 722   bool input_with_gnu_stack_note_;
 723   // Whether we have seen at least one object file without an
 724   // executable stack marker.
 725   bool input_without_gnu_stack_note_;
 726   // Whether we have seen an object file that uses the static TLS model.
 727   bool has_static_tls_;
 728   // Whether any sections require postprocessing.
 729   bool any_postprocessing_sections_;
 730   // Whether we have resized the signatures_ hash table.
 731   bool resized_signatures_;
 732   // In incremental build, holds information check the inputs and build the
 733   // .gnu_incremental_inputs section.
 734   Incremental_inputs* incremental_inputs_;
 735 };
 736
 737 // This task handles writing out data in output sections which is not
 738 // part of an input section, or which requires special handling.  When
 739 // this is done, it unblocks both output_sections_blocker and
 740 // final_blocker.
 741
 742 class Write_sections_task : public Task
 743 {
 744  public:
 745   Write_sections_task(const Layout* layout, Output_file* of,
 746                       Task_token* output_sections_blocker,
 747                       Task_token* final_blocker)
 748     : layout_(layout), of_(of),
 749       output_sections_blocker_(output_sections_blocker),
 750       final_blocker_(final_blocker)
 751   { }
 752
 753   // The standard Task methods.
 754
 755   Task_token*
 756   is_runnable();
 757
 758   void
 759   locks(Task_locker*);
 760
 761   void
 762   run(Workqueue*);
 763
 764   std::string
 765   get_name() const
 766   { return "Write_sections_task"; }
 767
 768  private:
 769   class Write_sections_locker;
 770
 771   const Layout* layout_;
 772   Output_file* of_;
 773   Task_token* output_sections_blocker_;
 774   Task_token* final_blocker_;
 775 };
 776
 777 // This task handles writing out data which is not part of a section
 778 // or segment.
 779
 780 class Write_data_task : public Task
 781 {
 782  public:
 783   Write_data_task(const Layout* layout, const Symbol_table* symtab,
 784                   Output_file* of, Task_token* final_blocker)
 785     : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
 786   { }
 787
 788   // The standard Task methods.
 789
 790   Task_token*
 791   is_runnable();
 792
 793   void
 794   locks(Task_locker*);
 795
 796   void
 797   run(Workqueue*);
 798
 799   std::string
 800   get_name() const
 801   { return "Write_data_task"; }
 802
 803  private:
 804   const Layout* layout_;
 805   const Symbol_table* symtab_;
 806   Output_file* of_;
 807   Task_token* final_blocker_;
 808 };
 809
 810 // This task handles writing out the global symbols.
 811
 812 class Write_symbols_task : public Task
 813 {
 814  public:
 815   Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
 816                      const Input_objects* input_objects,
 817                      const Stringpool* sympool, const Stringpool* dynpool,
 818                      Output_file* of, Task_token* final_blocker)
 819     : layout_(layout), symtab_(symtab), input_objects_(input_objects),
 820       sympool_(sympool), dynpool_(dynpool), of_(of),
 821       final_blocker_(final_blocker)
 822   { }
 823
 824   // The standard Task methods.
 825
 826   Task_token*
 827   is_runnable();
 828
 829   void
 830   locks(Task_locker*);
 831
 832   void
 833   run(Workqueue*);
 834
 835   std::string
 836   get_name() const
 837   { return "Write_symbols_task"; }
 838
 839  private:
 840   const Layout* layout_;
 841   const Symbol_table* symtab_;
 842   const Input_objects* input_objects_;
 843   const Stringpool* sympool_;
 844   const Stringpool* dynpool_;
 845   Output_file* of_;
 846   Task_token* final_blocker_;
 847 };
 848
 849 // This task handles writing out data in output sections which can't
 850 // be written out until all the input sections have been handled.
 851 // This is for sections whose contents is based on the contents of
 852 // other output sections.
 853
 854 class Write_after_input_sections_task : public Task
 855 {
 856  public:
 857   Write_after_input_sections_task(Layout* layout, Output_file* of,
 858                                   Task_token* input_sections_blocker,
 859                                   Task_token* final_blocker)
 860     : layout_(layout), of_(of),
 861       input_sections_blocker_(input_sections_blocker),
 862       final_blocker_(final_blocker)
 863   { }
 864
 865   // The standard Task methods.
 866
 867   Task_token*
 868   is_runnable();
 869
 870   void
 871   locks(Task_locker*);
 872
 873   void
 874   run(Workqueue*);
 875
 876   std::string
 877   get_name() const
 878   { return "Write_after_input_sections_task"; }
 879
 880  private:
 881   Layout* layout_;
 882   Output_file* of_;
 883   Task_token* input_sections_blocker_;
 884   Task_token* final_blocker_;
 885 };
 886
 887 // This task function handles closing the file.
 888
 889 class Close_task_runner : public Task_function_runner
 890 {
 891  public:
 892   Close_task_runner(const General_options* options, const Layout* layout,
 893                     Output_file* of)
 894     : options_(options), layout_(layout), of_(of)
 895   { }
 896
 897   // Run the operation.
 898   void
 899   run(Workqueue*, const Task*);
 900
 901  private:
 902   const General_options* options_;
 903   const Layout* layout_;
 904   Output_file* of_;
 905 };
 906
 907 // A small helper function to align an address.
 908
 909 inline uint64_t
 910 align_address(uint64_t address, uint64_t addralign)
 911 {
 912   if (addralign != 0)
 913     address = (address + addralign - 1) &~ (addralign - 1);
 914   return address;
 915 }
 916
 917 } // End namespace gold.
 918
 919 #endif // !defined(GOLD_LAYOUT_H)