gold/object.h

   1 // object.h -- support for an object file for linking in gold  -*- C++ -*-
   2
   3 // Copyright 2006, 2007 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_OBJECT_H
  24 #define GOLD_OBJECT_H
  25
  26 #include <string>
  27 #include <vector>
  28
  29 #include "elfcpp.h"
  30 #include "elfcpp_file.h"
  31 #include "fileread.h"
  32 #include "target.h"
  33
  34 namespace gold
  35 {
  36
  37 class General_options;
  38 class Layout;
  39 class Output_section;
  40 class Output_file;
  41 class Dynobj;
  42
  43 template<typename Stringpool_char>
  44 class Stringpool_template;
  45
  46 // Data to pass from read_symbols() to add_symbols().
  47
  48 struct Read_symbols_data
  49 {
  50   // Section headers.
  51   File_view* section_headers;
  52   // Section names.
  53   File_view* section_names;
  54   // Size of section name data in bytes.
  55   off_t section_names_size;
  56   // Symbol data.
  57   File_view* symbols;
  58   // Size of symbol data in bytes.
  59   off_t symbols_size;
  60   // Symbol names.
  61   File_view* symbol_names;
  62   // Size of symbol name data in bytes.
  63   off_t symbol_names_size;
  64
  65   // Version information.  This is only used on dynamic objects.
  66   // Version symbol data (from SHT_GNU_versym section).
  67   File_view* versym;
  68   off_t versym_size;
  69   // Version definition data (from SHT_GNU_verdef section).
  70   File_view* verdef;
  71   off_t verdef_size;
  72   unsigned int verdef_info;
  73   // Needed version data  (from SHT_GNU_verneed section).
  74   File_view* verneed;
  75   off_t verneed_size;
  76   unsigned int verneed_info;
  77 };
  78
  79 // Data about a single relocation section.  This is read in
  80 // read_relocs and processed in scan_relocs.
  81
  82 struct Section_relocs
  83 {
  84   // Index of reloc section.
  85   unsigned int reloc_shndx;
  86   // Index of section that relocs apply to.
  87   unsigned int data_shndx;
  88   // Contents of reloc section.
  89   File_view* contents;
  90   // Reloc section type.
  91   unsigned int sh_type;
  92   // Number of reloc entries.
  93   size_t reloc_count;
  94 };
  95
  96 // Relocations in an object file.  This is read in read_relocs and
  97 // processed in scan_relocs.
  98
  99 struct Read_relocs_data
 100 {
 101   typedef std::vector<Section_relocs> Relocs_list;
 102   // The relocations.
 103   Relocs_list relocs;
 104   // The local symbols.
 105   File_view* local_symbols;
 106 };
 107
 108 // Object is an abstract base class which represents either a 32-bit
 109 // or a 64-bit input object.  This can be a regular object file
 110 // (ET_REL) or a shared object (ET_DYN).
 111
 112 class Object
 113 {
 114  public:
 115   // NAME is the name of the object as we would report it to the user
 116   // (e.g., libfoo.a(bar.o) if this is in an archive.  INPUT_FILE is
 117   // used to read the file.  OFFSET is the offset within the input
 118   // file--0 for a .o or .so file, something else for a .a file.
 119   Object(const std::string& name, Input_file* input_file, bool is_dynamic,
 120          off_t offset = 0)
 121     : name_(name), input_file_(input_file), offset_(offset), shnum_(-1U),
 122       is_dynamic_(is_dynamic), target_(NULL)
 123   { }
 124
 125   virtual ~Object()
 126   { }
 127
 128   // Return the name of the object as we would report it to the tuser.
 129   const std::string&
 130   name() const
 131   { return this->name_; }
 132
 133   // Get the offset into the file.
 134   off_t
 135   offset() const
 136   { return this->offset_; }
 137
 138   // Return whether this is a dynamic object.
 139   bool
 140   is_dynamic() const
 141   { return this->is_dynamic_; }
 142
 143   // Return the target structure associated with this object.
 144   Target*
 145   target() const
 146   { return this->target_; }
 147
 148   // Lock the underlying file.
 149   void
 150   lock()
 151   { this->input_file_->file().lock(); }
 152
 153   // Unlock the underlying file.
 154   void
 155   unlock()
 156   { this->input_file_->file().unlock(); }
 157
 158   // Return whether the underlying file is locked.
 159   bool
 160   is_locked() const
 161   { return this->input_file_->file().is_locked(); }
 162
 163   // Return the sized target structure associated with this object.
 164   // This is like the target method but it returns a pointer of
 165   // appropriate checked type.
 166   template<int size, bool big_endian>
 167   Sized_target<size, big_endian>*
 168   sized_target(ACCEPT_SIZE_ENDIAN_ONLY);
 169
 170   // Get the number of sections.
 171   unsigned int
 172   shnum() const
 173   { return this->shnum_; }
 174
 175   // Return a view of the contents of a section.  Set *PLEN to the
 176   // size.  CACHE is a hint as in File_read::get_view.
 177   const unsigned char*
 178   section_contents(unsigned int shndx, off_t* plen, bool cache);
 179
 180   // Return the name of a section given a section index.  This is only
 181   // used for error messages.
 182   std::string
 183   section_name(unsigned int shndx)
 184   { return this->do_section_name(shndx); }
 185
 186   // Return the section flags given a section index.
 187   uint64_t
 188   section_flags(unsigned int shndx)
 189   { return this->do_section_flags(shndx); }
 190
 191   // Read the symbol information.
 192   void
 193   read_symbols(Read_symbols_data* sd)
 194   { return this->do_read_symbols(sd); }
 195
 196   // Pass sections which should be included in the link to the Layout
 197   // object, and record where the sections go in the output file.
 198   void
 199   layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd)
 200   { this->do_layout(symtab, layout, sd); }
 201
 202   // Add symbol information to the global symbol table.
 203   void
 204   add_symbols(Symbol_table* symtab, Read_symbols_data* sd)
 205   { this->do_add_symbols(symtab, sd); }
 206
 207   // Functions and types for the elfcpp::Elf_file interface.  This
 208   // permit us to use Object as the File template parameter for
 209   // elfcpp::Elf_file.
 210
 211   // The View class is returned by view.  It must support a single
 212   // method, data().  This is trivial, because get_view does what we
 213   // need.
 214   class View
 215   {
 216    public:
 217     View(const unsigned char* p)
 218       : p_(p)
 219     { }
 220
 221     const unsigned char*
 222     data() const
 223     { return this->p_; }
 224
 225    private:
 226     const unsigned char* p_;
 227   };
 228
 229   // Return a View.
 230   View
 231   view(off_t file_offset, off_t data_size)
 232   { return View(this->get_view(file_offset, data_size, true)); }
 233
 234   // Report an error.
 235   void
 236   error(const char* format, ...) const ATTRIBUTE_PRINTF_2;
 237
 238   // A location in the file.
 239   struct Location
 240   {
 241     off_t file_offset;
 242     off_t data_size;
 243
 244     Location(off_t fo, off_t ds)
 245       : file_offset(fo), data_size(ds)
 246     { }
 247   };
 248
 249   // Get a View given a Location.
 250   View view(Location loc)
 251   { return View(this->get_view(loc.file_offset, loc.data_size, true)); }
 252
 253  protected:
 254   // Read the symbols--implemented by child class.
 255   virtual void
 256   do_read_symbols(Read_symbols_data*) = 0;
 257
 258   // Lay out sections--implemented by child class.
 259   virtual void
 260   do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0;
 261
 262   // Add symbol information to the global symbol table--implemented by
 263   // child class.
 264   virtual void
 265   do_add_symbols(Symbol_table*, Read_symbols_data*) = 0;
 266
 267   // Return the location of the contents of a section.  Implemented by
 268   // child class.
 269   virtual Location
 270   do_section_contents(unsigned int shndx) = 0;
 271
 272   // Get the name of a section--implemented by child class.
 273   virtual std::string
 274   do_section_name(unsigned int shndx) = 0;
 275
 276   // Get section flags--implemented by child class.
 277   virtual uint64_t
 278   do_section_flags(unsigned int shndx) = 0;
 279
 280   // Get the file.
 281   Input_file*
 282   input_file() const
 283   { return this->input_file_; }
 284
 285   // Get a view into the underlying file.
 286   const unsigned char*
 287   get_view(off_t start, off_t size, bool cache)
 288   {
 289     return this->input_file_->file().get_view(start + this->offset_, size,
 290                                               cache);
 291   }
 292
 293   // Get a lasting view into the underlying file.
 294   File_view*
 295   get_lasting_view(off_t start, off_t size, bool cache)
 296   {
 297     return this->input_file_->file().get_lasting_view(start + this->offset_,
 298                                                       size, cache);
 299   }
 300
 301   // Read data from the underlying file.
 302   void
 303   read(off_t start, off_t size, void* p)
 304   { this->input_file_->file().read(start + this->offset_, size, p); }
 305
 306   // Set the target.
 307   void
 308   set_target(int machine, int size, bool big_endian, int osabi,
 309              int abiversion);
 310
 311   // Set the number of sections.
 312   void
 313   set_shnum(int shnum)
 314   { this->shnum_ = shnum; }
 315
 316   // Functions used by both Sized_relobj and Sized_dynobj.
 317
 318   // Read the section data into a Read_symbols_data object.
 319   template<int size, bool big_endian>
 320   void
 321   read_section_data(elfcpp::Elf_file<size, big_endian, Object>*,
 322                     Read_symbols_data*);
 323
 324   // If NAME is the name of a special .gnu.warning section, arrange
 325   // for the warning to be issued.  SHNDX is the section index.
 326   // Return whether it is a warning section.
 327   bool
 328   handle_gnu_warning_section(const char* name, unsigned int shndx,
 329                              Symbol_table*);
 330
 331  private:
 332   // This class may not be copied.
 333   Object(const Object&);
 334   Object& operator=(const Object&);
 335
 336   // Name of object as printed to user.
 337   std::string name_;
 338   // For reading the file.
 339   Input_file* input_file_;
 340   // Offset within the file--0 for an object file, non-0 for an
 341   // archive.
 342   off_t offset_;
 343   // Number of input sections.
 344   unsigned int shnum_;
 345   // Whether this is a dynamic object.
 346   bool is_dynamic_;
 347   // Target functions--may be NULL if the target is not known.
 348   Target* target_;
 349 };
 350
 351 // Implement sized_target inline for efficiency.  This approach breaks
 352 // static type checking, but is made safe using asserts.
 353
 354 template<int size, bool big_endian>
 355 inline Sized_target<size, big_endian>*
 356 Object::sized_target(ACCEPT_SIZE_ENDIAN_ONLY)
 357 {
 358   gold_assert(this->target_->get_size() == size);
 359   gold_assert(this->target_->is_big_endian() ? big_endian : !big_endian);
 360   return static_cast<Sized_target<size, big_endian>*>(this->target_);
 361 }
 362
 363 // A regular object (ET_REL).  This is an abstract base class itself.
 364 // The implementation is the template class Sized_relobj.
 365
 366 class Relobj : public Object
 367 {
 368  public:
 369   Relobj(const std::string& name, Input_file* input_file, off_t offset = 0)
 370     : Object(name, input_file, false, offset)
 371   { }
 372
 373   // Read the relocs.
 374   void
 375   read_relocs(Read_relocs_data* rd)
 376   { return this->do_read_relocs(rd); }
 377
 378   // Scan the relocs and adjust the symbol table.
 379   void
 380   scan_relocs(const General_options& options, Symbol_table* symtab,
 381               Layout* layout, Read_relocs_data* rd)
 382   { return this->do_scan_relocs(options, symtab, layout, rd); }
 383
 384   // Initial local symbol processing: set the offset where local
 385   // symbol information will be stored; add local symbol names to
 386   // *POOL; return the new local symbol index.
 387   unsigned int
 388   finalize_local_symbols(unsigned int index, off_t off,
 389                          Stringpool_template<char>* pool)
 390   { return this->do_finalize_local_symbols(index, off, pool); }
 391
 392   // Relocate the input sections and write out the local symbols.
 393   void
 394   relocate(const General_options& options, const Symbol_table* symtab,
 395            const Layout* layout, Output_file* of)
 396   { return this->do_relocate(options, symtab, layout, of); }
 397
 398   // Return whether an input section is being included in the link.
 399   bool
 400   is_section_included(unsigned int shndx) const
 401   {
 402     gold_assert(shndx < this->map_to_output_.size());
 403     return this->map_to_output_[shndx].output_section != NULL;
 404   }
 405
 406   // Given a section index, return the corresponding Output_section
 407   // (which will be NULL if the section is not included in the link)
 408   // and set *POFF to the offset within that section.
 409   inline Output_section*
 410   output_section(unsigned int shndx, off_t* poff) const;
 411
 412   // Set the offset of an input section within its output section.
 413   void
 414   set_section_offset(unsigned int shndx, off_t off)
 415   {
 416     gold_assert(shndx < this->map_to_output_.size());
 417     this->map_to_output_[shndx].offset = off;
 418   }
 419
 420  protected:
 421   // What we need to know to map an input section to an output
 422   // section.  We keep an array of these, one for each input section,
 423   // indexed by the input section number.
 424   struct Map_to_output
 425   {
 426     // The output section.  This is NULL if the input section is to be
 427     // discarded.
 428     Output_section* output_section;
 429     // The offset within the output section.  This is -1 if the
 430     // section requires special handling.
 431     off_t offset;
 432   };
 433
 434   // Read the relocs--implemented by child class.
 435   virtual void
 436   do_read_relocs(Read_relocs_data*) = 0;
 437
 438   // Scan the relocs--implemented by child class.
 439   virtual void
 440   do_scan_relocs(const General_options&, Symbol_table*, Layout*,
 441                  Read_relocs_data*) = 0;
 442
 443   // Finalize local symbols--implemented by child class.
 444   virtual unsigned int
 445   do_finalize_local_symbols(unsigned int, off_t,
 446                             Stringpool_template<char>*) = 0;
 447
 448   // Relocate the input sections and write out the local
 449   // symbols--implemented by child class.
 450   virtual void
 451   do_relocate(const General_options& options, const Symbol_table* symtab,
 452               const Layout*, Output_file* of) = 0;
 453
 454   // Return the vector mapping input sections to output sections.
 455   std::vector<Map_to_output>&
 456   map_to_output()
 457   { return this->map_to_output_; }
 458
 459   const std::vector<Map_to_output>&
 460   map_to_output() const
 461   { return this->map_to_output_; }
 462
 463  private:
 464   // Mapping from input sections to output section.
 465   std::vector<Map_to_output> map_to_output_;
 466 };
 467
 468 // Implement Object::output_section inline for efficiency.
 469 inline Output_section*
 470 Relobj::output_section(unsigned int shndx, off_t* poff) const
 471 {
 472   gold_assert(shndx < this->map_to_output_.size());
 473   const Map_to_output& mo(this->map_to_output_[shndx]);
 474   *poff = mo.offset;
 475   return mo.output_section;
 476 }
 477
 478 // This POD class is holds the value of a symbol.  This is used for
 479 // local symbols, and for all symbols during relocation processing.
 480 // In order to process relocs we need to be able to handle SHF_MERGE
 481 // sections correctly.
 482
 483 template<int size>
 484 class Symbol_value
 485 {
 486  public:
 487   typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
 488
 489   Symbol_value()
 490     : output_symtab_index_(0), input_shndx_(0), is_section_symbol_(false),
 491       needs_output_address_(false), value_(0)
 492   { }
 493
 494   // Get the value of this symbol.  OBJECT is the object in which this
 495   // symbol is defined, and ADDEND is an addend to add to the value.
 496   template<bool big_endian>
 497   Value
 498   value(const Sized_relobj<size, big_endian>* object, Value addend) const
 499   {
 500     if (!this->needs_output_address_)
 501       return this->value_ + addend;
 502     return object->local_value(this->input_shndx_, this->value_,
 503                                this->is_section_symbol_, addend);
 504   }
 505
 506   // Set the value of this symbol in the output symbol table.
 507   void
 508   set_output_value(Value value)
 509   {
 510     this->value_ = value;
 511     this->needs_output_address_ = false;
 512   }
 513
 514   // If this symbol is mapped to an output section which requires
 515   // special handling to determine the output value, we store the
 516   // value of the symbol in the input file.  This is used for
 517   // SHF_MERGE sections.
 518   void
 519   set_input_value(Value value)
 520   {
 521     this->value_ = value;
 522     this->needs_output_address_ = true;
 523   }
 524
 525   // Return whether this symbol should go into the output symbol
 526   // table.
 527   bool
 528   needs_output_symtab_entry() const
 529   {
 530     gold_assert(this->output_symtab_index_ != 0);
 531     return this->output_symtab_index_ != -1U;
 532   }
 533
 534   // Return the index in the output symbol table.
 535   unsigned int
 536   output_symtab_index() const
 537   {
 538     gold_assert(this->output_symtab_index_ != 0);
 539     return this->output_symtab_index_;
 540   }
 541
 542   // Set the index in the output symbol table.
 543   void
 544   set_output_symtab_index(unsigned int i)
 545   {
 546     gold_assert(this->output_symtab_index_ == 0);
 547     this->output_symtab_index_ = i;
 548   }
 549
 550   // Record that this symbol should not go into the output symbol
 551   // table.
 552   void
 553   set_no_output_symtab_entry()
 554   {
 555     gold_assert(this->output_symtab_index_ == 0);
 556     this->output_symtab_index_ = -1U;
 557   }
 558
 559   // Set the index of the input section in the input file.
 560   void
 561   set_input_shndx(unsigned int i)
 562   { this->input_shndx_ = i; }
 563
 564   // Record that this is a section symbol.
 565   void
 566   set_is_section_symbol()
 567   { this->is_section_symbol_ = true; }
 568
 569  private:
 570   // The index of this local symbol in the output symbol table.  This
 571   // will be -1 if the symbol should not go into the symbol table.
 572   unsigned int output_symtab_index_;
 573   // The section index in the input file in which this symbol is
 574   // defined.
 575   unsigned int input_shndx_ : 30;
 576   // Whether this is a STT_SECTION symbol.
 577   bool is_section_symbol_ : 1;
 578   // Whether getting the value of this symbol requires calling an
 579   // Output_section method.  For example, this will be true of a
 580   // symbol in a SHF_MERGE section.
 581   bool needs_output_address_ : 1;
 582   // The value of the symbol.  If !needs_output_address_, this is the
 583   // value in the output file.  If needs_output_address_, this is the
 584   // value in the input file.
 585   Value value_;
 586 };
 587
 588 // A regular object file.  This is size and endian specific.
 589
 590 template<int size, bool big_endian>
 591 class Sized_relobj : public Relobj
 592 {
 593  public:
 594   typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
 595   typedef std::vector<Symbol_value<size> > Local_values;
 596
 597   Sized_relobj(const std::string& name, Input_file* input_file, off_t offset,
 598                const typename elfcpp::Ehdr<size, big_endian>&);
 599
 600   ~Sized_relobj();
 601
 602   // Set up the object file based on the ELF header.
 603   void
 604   setup(const typename elfcpp::Ehdr<size, big_endian>&);
 605
 606   // Return the index of local symbol SYM in the ordinary symbol
 607   // table.  A value of -1U means that the symbol is not being output.
 608   unsigned int
 609   symtab_index(unsigned int sym) const
 610   {
 611     gold_assert(sym < this->local_values_.size());
 612     return this->local_values_[sym].output_symtab_index();
 613   }
 614
 615   // Return the appropriate Sized_target structure.
 616   Sized_target<size, big_endian>*
 617   sized_target()
 618   {
 619     return this->Object::sized_target
 620       SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
 621           SELECT_SIZE_ENDIAN_ONLY(size, big_endian));
 622   }
 623
 624   // Return the value of the local symbol symndx.
 625   Address
 626   local_symbol_value(unsigned int symndx) const;
 627
 628   // Return the value of a local symbol defined in input section
 629   // SHNDX, with value VALUE, adding addend ADDEND.  IS_SECTION_SYMBOL
 630   // indicates whether the symbol is a section symbol.  This handles
 631   // SHF_MERGE sections.
 632   Address
 633   local_value(unsigned int shndx, Address value, bool is_section_symbol,
 634               Address addend) const;
 635
 636   // Return whether the local symbol SYMNDX has a GOT offset.
 637   bool
 638   local_has_got_offset(unsigned int symndx) const
 639   {
 640     return (this->local_got_offsets_.find(symndx)
 641             != this->local_got_offsets_.end());
 642   }
 643
 644   // Return the GOT offset of the local symbol SYMNDX.
 645   unsigned int
 646   local_got_offset(unsigned int symndx) const
 647   {
 648     Local_got_offsets::const_iterator p =
 649         this->local_got_offsets_.find(symndx);
 650     gold_assert(p != this->local_got_offsets_.end());
 651     return p->second;
 652   }
 653
 654   // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
 655   void
 656   set_local_got_offset(unsigned int symndx, unsigned int got_offset)
 657   {
 658     std::pair<Local_got_offsets::iterator, bool> ins =
 659         this->local_got_offsets_.insert(std::make_pair(symndx, got_offset));
 660     gold_assert(ins.second);
 661   }
 662
 663   // Read the symbols.
 664   void
 665   do_read_symbols(Read_symbols_data*);
 666
 667   // Lay out the input sections.
 668   void
 669   do_layout(Symbol_table*, Layout*, Read_symbols_data*);
 670
 671   // Add the symbols to the symbol table.
 672   void
 673   do_add_symbols(Symbol_table*, Read_symbols_data*);
 674
 675   // Read the relocs.
 676   void
 677   do_read_relocs(Read_relocs_data*);
 678
 679   // Scan the relocs and adjust the symbol table.
 680   void
 681   do_scan_relocs(const General_options&, Symbol_table*, Layout*,
 682                  Read_relocs_data*);
 683
 684   // Finalize the local symbols.
 685   unsigned int
 686   do_finalize_local_symbols(unsigned int, off_t,
 687                             Stringpool_template<char>*);
 688
 689   // Relocate the input sections and write out the local symbols.
 690   void
 691   do_relocate(const General_options& options, const Symbol_table* symtab,
 692               const Layout*, Output_file* of);
 693
 694   // Get the name of a section.
 695   std::string
 696   do_section_name(unsigned int shndx)
 697   { return this->elf_file_.section_name(shndx); }
 698
 699   // Return the location of the contents of a section.
 700   Object::Location
 701   do_section_contents(unsigned int shndx)
 702   { return this->elf_file_.section_contents(shndx); }
 703
 704   // Return section flags.
 705   uint64_t
 706   do_section_flags(unsigned int shndx)
 707   { return this->elf_file_.section_flags(shndx); }
 708
 709  private:
 710   // For convenience.
 711   typedef Sized_relobj<size, big_endian> This;
 712   static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
 713   static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
 714   static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
 715   typedef elfcpp::Shdr<size, big_endian> Shdr;
 716
 717   // Find the SHT_SYMTAB section, given the section headers.
 718   void
 719   find_symtab(const unsigned char* pshdrs);
 720
 721   // Whether to include a section group in the link.
 722   bool
 723   include_section_group(Layout*, unsigned int,
 724                         const elfcpp::Shdr<size, big_endian>&,
 725                         std::vector<bool>*);
 726
 727   // Whether to include a linkonce section in the link.
 728   bool
 729   include_linkonce_section(Layout*, const char*,
 730                            const elfcpp::Shdr<size, big_endian>&);
 731
 732   // Views and sizes when relocating.
 733   struct View_size
 734   {
 735     unsigned char* view;
 736     typename elfcpp::Elf_types<size>::Elf_Addr address;
 737     off_t offset;
 738     off_t view_size;
 739   };
 740
 741   typedef std::vector<View_size> Views;
 742
 743   // Write section data to the output file.  Record the views and
 744   // sizes in VIEWS for use when relocating.
 745   void
 746   write_sections(const unsigned char* pshdrs, Output_file*, Views*);
 747
 748   // Relocate the sections in the output file.
 749   void
 750   relocate_sections(const General_options& options, const Symbol_table*,
 751                     const Layout*, const unsigned char* pshdrs, Views*);
 752
 753   // Write out the local symbols.
 754   void
 755   write_local_symbols(Output_file*,
 756                       const Stringpool_template<char>*);
 757
 758   // The GOT offsets of local symbols.
 759   typedef Unordered_map<unsigned int, unsigned int> Local_got_offsets;
 760
 761   // General access to the ELF file.
 762   elfcpp::Elf_file<size, big_endian, Object> elf_file_;
 763   // Index of SHT_SYMTAB section.
 764   unsigned int symtab_shndx_;
 765   // The number of local symbols.
 766   unsigned int local_symbol_count_;
 767   // The number of local symbols which go into the output file.
 768   unsigned int output_local_symbol_count_;
 769   // The entries in the symbol table for the external symbols.
 770   Symbol** symbols_;
 771   // File offset for local symbols.
 772   off_t local_symbol_offset_;
 773   // Values of local symbols.
 774   Local_values local_values_;
 775   // GOT offsets for local symbols, indexed by symbol number.
 776   Local_got_offsets local_got_offsets_;
 777 };
 778
 779 // A class to manage the list of all objects.
 780
 781 class Input_objects
 782 {
 783  public:
 784   Input_objects()
 785     : relobj_list_(), dynobj_list_(), target_(NULL), sonames_()
 786   { }
 787
 788   // The type of the list of input relocateable objects.
 789   typedef std::vector<Relobj*> Relobj_list;
 790   typedef Relobj_list::const_iterator Relobj_iterator;
 791
 792   // The type of the list of input dynamic objects.
 793   typedef std::vector<Dynobj*> Dynobj_list;
 794   typedef Dynobj_list::const_iterator Dynobj_iterator;
 795
 796   // Add an object to the list.  Return true if all is well, or false
 797   // if this object should be ignored.
 798   bool
 799   add_object(Object*);
 800
 801   // Get the target we should use for the output file.
 802   Target*
 803   target() const
 804   { return this->target_; }
 805
 806   // Iterate over all regular objects.
 807
 808   Relobj_iterator
 809   relobj_begin() const
 810   { return this->relobj_list_.begin(); }
 811
 812   Relobj_iterator
 813   relobj_end() const
 814   { return this->relobj_list_.end(); }
 815
 816   // Iterate over all dynamic objects.
 817
 818   Dynobj_iterator
 819   dynobj_begin() const
 820   { return this->dynobj_list_.begin(); }
 821
 822   Dynobj_iterator
 823   dynobj_end() const
 824   { return this->dynobj_list_.end(); }
 825
 826   // Return whether we have seen any dynamic objects.
 827   bool
 828   any_dynamic() const
 829   { return !this->dynobj_list_.empty(); }
 830
 831  private:
 832   Input_objects(const Input_objects&);
 833   Input_objects& operator=(const Input_objects&);
 834
 835   // The list of ordinary objects included in the link.
 836   Relobj_list relobj_list_;
 837   // The list of dynamic objects included in the link.
 838   Dynobj_list dynobj_list_;
 839   // The target.
 840   Target* target_;
 841   // SONAMEs that we have seen.
 842   Unordered_set<std::string> sonames_;
 843 };
 844
 845 // Some of the information we pass to the relocation routines.  We
 846 // group this together to avoid passing a dozen different arguments.
 847
 848 template<int size, bool big_endian>
 849 struct Relocate_info
 850 {
 851   // Command line options.
 852   const General_options* options;
 853   // Symbol table.
 854   const Symbol_table* symtab;
 855   // Layout.
 856   const Layout* layout;
 857   // Object being relocated.
 858   Sized_relobj<size, big_endian>* object;
 859   // Number of local symbols.
 860   unsigned int local_symbol_count;
 861   // Values of local symbols.
 862   const typename Sized_relobj<size, big_endian>::Local_values* local_values;
 863   // Global symbols.
 864   const Symbol* const * symbols;
 865   // Section index of relocation section.
 866   unsigned int reloc_shndx;
 867   // Section index of section being relocated.
 868   unsigned int data_shndx;
 869
 870   // Return a string showing the location of a relocation.  This is
 871   // only used for error messages.
 872   std::string
 873   location(size_t relnum, off_t reloffset) const;
 874 };
 875
 876 // Return an Object appropriate for the input file.  P is BYTES long,
 877 // and holds the ELF header.
 878
 879 extern Object*
 880 make_elf_object(const std::string& name, Input_file*,
 881                 off_t offset, const unsigned char* p,
 882                 off_t bytes);
 883
 884 } // end namespace gold
 885
 886 #endif // !defined(GOLD_OBJECT_H)