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