gold/symtab.h

   1 // symtab.h -- the gold symbol table   -*- C++ -*-
   2
   3 // Symbol_table
   4 //   The symbol table.
   5
   6 #include <string>
   7 #include <utility>
   8 #include <vector>
   9 #include <cassert>
  10
  11 #include "elfcpp.h"
  12 #include "stringpool.h"
  13 #include "object.h"
  14
  15 #ifndef GOLD_SYMTAB_H
  16 #define GOLD_SYMTAB_H
  17
  18 namespace gold
  19 {
  20
  21 class Object;
  22 class Relobj;
  23 class Dynobj;
  24 class Output_data;
  25 class Output_segment;
  26 class Output_file;
  27 class Target;
  28
  29 // The base class of an entry in the symbol table.  The symbol table
  30 // can have a lot of entries, so we don't want this class to big.
  31 // Size dependent fields can be found in the template class
  32 // Sized_symbol.  Targets may support their own derived classes.
  33
  34 class Symbol
  35 {
  36  public:
  37   // Because we want the class to be small, we don't use any virtual
  38   // functions.  But because symbols can be defined in different
  39   // places, we need to classify them.  This enum is the different
  40   // sources of symbols we support.
  41   enum Source
  42   {
  43     // Symbol defined in a relocatable or dynamic input file--this is
  44     // the most common case.
  45     FROM_OBJECT,
  46     // Symbol defined in an Output_data, a special section created by
  47     // the target.
  48     IN_OUTPUT_DATA,
  49     // Symbol defined in an Output_segment, with no associated
  50     // section.
  51     IN_OUTPUT_SEGMENT,
  52     // Symbol value is constant.
  53     CONSTANT
  54   };
  55
  56   // When the source is IN_OUTPUT_SEGMENT, we need to describe what
  57   // the offset means.
  58   enum Segment_offset_base
  59   {
  60     // From the start of the segment.
  61     SEGMENT_START,
  62     // From the end of the segment.
  63     SEGMENT_END,
  64     // From the filesz of the segment--i.e., after the loaded bytes
  65     // but before the bytes which are allocated but zeroed.
  66     SEGMENT_BSS
  67   };
  68
  69   // Return the symbol name.
  70   const char*
  71   name() const
  72   { return this->name_; }
  73
  74   // Return the symbol version.  This will return NULL for an
  75   // unversioned symbol.
  76   const char*
  77   version() const
  78   { return this->version_; }
  79
  80   // Return the symbol source.
  81   Source
  82   source() const
  83   { return this->source_; }
  84
  85   // Return the object with which this symbol is associated.
  86   Object*
  87   object() const
  88   {
  89     assert(this->source_ == FROM_OBJECT);
  90     return this->u_.from_object.object;
  91   }
  92
  93   // Return the index of the section in the input relocatable or
  94   // dynamic object file.
  95   unsigned int
  96   shnum() const
  97   {
  98     assert(this->source_ == FROM_OBJECT);
  99     return this->u_.from_object.shnum;
 100   }
 101
 102   // Return the output data section with which this symbol is
 103   // associated, if the symbol was specially defined with respect to
 104   // an output data section.
 105   Output_data*
 106   output_data() const
 107   {
 108     assert(this->source_ == IN_OUTPUT_DATA);
 109     return this->u_.in_output_data.output_data;
 110   }
 111
 112   // If this symbol was defined with respect to an output data
 113   // section, return whether the value is an offset from end.
 114   bool
 115   offset_is_from_end() const
 116   {
 117     assert(this->source_ == IN_OUTPUT_DATA);
 118     return this->u_.in_output_data.offset_is_from_end;
 119   }
 120
 121   // Return the output segment with which this symbol is associated,
 122   // if the symbol was specially defined with respect to an output
 123   // segment.
 124   Output_segment*
 125   output_segment() const
 126   {
 127     assert(this->source_ == IN_OUTPUT_SEGMENT);
 128     return this->u_.in_output_segment.output_segment;
 129   }
 130
 131   // If this symbol was defined with respect to an output segment,
 132   // return the offset base.
 133   Segment_offset_base
 134   offset_base() const
 135   {
 136     assert(this->source_ == IN_OUTPUT_SEGMENT);
 137     return this->u_.in_output_segment.offset_base;
 138   }
 139
 140   // Return the symbol binding.
 141   elfcpp::STB
 142   binding() const
 143   { return this->binding_; }
 144
 145   // Return the symbol type.
 146   elfcpp::STT
 147   type() const
 148   { return this->type_; }
 149
 150   // Return the symbol visibility.
 151   elfcpp::STV
 152   visibility() const
 153   { return this->visibility_; }
 154
 155   // Return the non-visibility part of the st_other field.
 156   unsigned char
 157   nonvis() const
 158   { return this->nonvis_; }
 159
 160   // Return whether this symbol is a forwarder.  This will never be
 161   // true of a symbol found in the hash table, but may be true of
 162   // symbol pointers attached to object files.
 163   bool
 164   is_forwarder() const
 165   { return this->is_forwarder_; }
 166
 167   // Mark this symbol as a forwarder.
 168   void
 169   set_forwarder()
 170   { this->is_forwarder_ = true; }
 171
 172   // Return whether this symbol was ever seen in a dynamic object.
 173   bool
 174   in_dyn() const
 175   { return this->in_dyn_; }
 176
 177   // Mark this symbol as having been seen in a dynamic object.
 178   void
 179   set_in_dyn()
 180   { this->in_dyn_ = true; }
 181
 182   // Return whether this symbol has an entry in the GOT section.
 183   bool
 184   has_got_offset() const
 185   { return this->has_got_offset_; }
 186
 187   // Return the offset into the GOT section of this symbol.
 188   unsigned int
 189   got_offset() const
 190   {
 191     assert(this->has_got_offset());
 192     return this->got_offset_;
 193   }
 194
 195   // Set the GOT offset of this symbol.
 196   void
 197   set_got_offset(unsigned int got_offset)
 198   {
 199     this->has_got_offset_ = true;
 200     this->got_offset_ = got_offset;
 201   }
 202
 203   // Return whether this symbol is resolved locally.  This is always
 204   // true when linking statically.  It is true for a symbol defined in
 205   // this object when using -Bsymbolic.  It is true for a symbol
 206   // marked local in a version file.  FIXME: This needs to be
 207   // completed.
 208   bool
 209   is_resolved_locally() const
 210   { return !this->in_dyn_; }
 211
 212   // Return whether this is a defined symbol (not undefined or
 213   // common).
 214   bool
 215   is_defined() const
 216   {
 217     return (this->source_ != FROM_OBJECT
 218             || (this->u_.from_object.shnum != elfcpp::SHN_UNDEF
 219                 && this->u_.from_object.shnum != elfcpp::SHN_COMMON));
 220   }
 221
 222   // Return whether this is an undefined symbol.
 223   bool
 224   is_undefined() const
 225   {
 226     return this->source_ == FROM_OBJECT && this->shnum() == elfcpp::SHN_UNDEF;
 227   }
 228
 229   // Return whether this is a common symbol.
 230   bool
 231   is_common() const
 232   {
 233     return (this->source_ == FROM_OBJECT
 234             && (this->u_.from_object.shnum == elfcpp::SHN_COMMON
 235                 || this->type_ == elfcpp::STT_COMMON));
 236   }
 237
 238   // Return whether there should be a warning for references to this
 239   // symbol.
 240   bool
 241   has_warning() const
 242   { return this->has_warning_; }
 243
 244   // Mark this symbol as having a warning.
 245   void
 246   set_has_warning()
 247   { this->has_warning_ = true; }
 248
 249  protected:
 250   // Instances of this class should always be created at a specific
 251   // size.
 252   Symbol()
 253   { memset(this, 0, sizeof *this); }
 254
 255   // Initialize the general fields.
 256   void
 257   init_fields(const char* name, const char* version,
 258               elfcpp::STT type, elfcpp::STB binding,
 259               elfcpp::STV visibility, unsigned char nonvis);
 260
 261   // Initialize fields from an ELF symbol in OBJECT.
 262   template<int size, bool big_endian>
 263   void
 264   init_base(const char *name, const char* version, Object* object,
 265             const elfcpp::Sym<size, big_endian>&);
 266
 267   // Initialize fields for an Output_data.
 268   void
 269   init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
 270             elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
 271
 272   // Initialize fields for an Output_segment.
 273   void
 274   init_base(const char* name, Output_segment* os, elfcpp::STT type,
 275             elfcpp::STB binding, elfcpp::STV visibility,
 276             unsigned char nonvis, Segment_offset_base offset_base);
 277
 278   // Initialize fields for a constant.
 279   void
 280   init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
 281             elfcpp::STV visibility, unsigned char nonvis);
 282
 283   // Override existing symbol.
 284   template<int size, bool big_endian>
 285   void
 286   override_base(const elfcpp::Sym<size, big_endian>&, Object* object);
 287
 288  private:
 289   Symbol(const Symbol&);
 290   Symbol& operator=(const Symbol&);
 291
 292   // Symbol name (expected to point into a Stringpool).
 293   const char* name_;
 294   // Symbol version (expected to point into a Stringpool).  This may
 295   // be NULL.
 296   const char* version_;
 297
 298   union
 299   {
 300     // This struct is used if SOURCE_ == FROM_OBJECT.
 301     struct
 302     {
 303       // Object in which symbol is defined, or in which it was first
 304       // seen.
 305       Object* object;
 306       // Section number in object_ in which symbol is defined.
 307       unsigned int shnum;
 308     } from_object;
 309
 310     // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
 311     struct
 312     {
 313       // Output_data in which symbol is defined.  Before
 314       // Layout::finalize the symbol's value is an offset within the
 315       // Output_data.
 316       Output_data* output_data;
 317       // True if the offset is from the end, false if the offset is
 318       // from the beginning.
 319       bool offset_is_from_end;
 320     } in_output_data;
 321
 322     // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
 323     struct
 324     {
 325       // Output_segment in which the symbol is defined.  Before
 326       // Layout::finalize the symbol's value is an offset.
 327       Output_segment* output_segment;
 328       // The base to use for the offset before Layout::finalize.
 329       Segment_offset_base offset_base;
 330     } in_output_segment;
 331   } u_;
 332
 333   // If this symbol has an entry in the GOT section (has_got_offset_
 334   // is true), this is the offset.
 335   unsigned int got_offset_;
 336   // Symbol type.
 337   elfcpp::STT type_ : 4;
 338   // Symbol binding.
 339   elfcpp::STB binding_ : 4;
 340   // Symbol visibility.
 341   elfcpp::STV visibility_ : 2;
 342   // Rest of symbol st_other field.
 343   unsigned int nonvis_ : 6;
 344   // The type of symbol.
 345   Source source_ : 3;
 346   // True if this symbol always requires special target-specific
 347   // handling.
 348   bool is_target_special_ : 1;
 349   // True if this is the default version of the symbol.
 350   bool is_def_ : 1;
 351   // True if this symbol really forwards to another symbol.  This is
 352   // used when we discover after the fact that two different entries
 353   // in the hash table really refer to the same symbol.  This will
 354   // never be set for a symbol found in the hash table, but may be set
 355   // for a symbol found in the list of symbols attached to an Object.
 356   // It forwards to the symbol found in the forwarders_ map of
 357   // Symbol_table.
 358   bool is_forwarder_ : 1;
 359   // True if we've seen this symbol in a dynamic object.
 360   bool in_dyn_ : 1;
 361   // True if the symbol has an entry in the GOT section.
 362   bool has_got_offset_ : 1;
 363   // True if there is a warning for this symbol.
 364   bool has_warning_ : 1;
 365 };
 366
 367 // The parts of a symbol which are size specific.  Using a template
 368 // derived class like this helps us use less space on a 32-bit system.
 369
 370 template<int size>
 371 class Sized_symbol : public Symbol
 372 {
 373  public:
 374   typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
 375   typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
 376
 377   Sized_symbol()
 378   { }
 379
 380   // Initialize fields from an ELF symbol in OBJECT.
 381   template<bool big_endian>
 382   void
 383   init(const char *name, const char* version, Object* object,
 384        const elfcpp::Sym<size, big_endian>&);
 385
 386   // Initialize fields for an Output_data.
 387   void
 388   init(const char* name, Output_data*, Value_type value, Size_type symsize,
 389        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 390        bool offset_is_from_end);
 391
 392   // Initialize fields for an Output_segment.
 393   void
 394   init(const char* name, Output_segment*, Value_type value, Size_type symsize,
 395        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 396        Segment_offset_base offset_base);
 397
 398   // Initialize fields for a constant.
 399   void
 400   init(const char* name, Value_type value, Size_type symsize,
 401        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
 402
 403   // Override existing symbol.
 404   template<bool big_endian>
 405   void
 406   override(const elfcpp::Sym<size, big_endian>&, Object* object);
 407
 408   // Return the symbol's value.
 409   Value_type
 410   value() const
 411   { return this->value_; }
 412
 413   // Return the symbol's size (we can't call this 'size' because that
 414   // is a template parameter).
 415   Size_type
 416   symsize() const
 417   { return this->symsize_; }
 418
 419   // Set the symbol size.  This is used when resolving common symbols.
 420   void
 421   set_symsize(Size_type symsize)
 422   { this->symsize_ = symsize; }
 423
 424   // Set the symbol value.  This is called when we store the final
 425   // values of the symbols into the symbol table.
 426   void
 427   set_value(Value_type value)
 428   { this->value_ = value; }
 429
 430  private:
 431   Sized_symbol(const Sized_symbol&);
 432   Sized_symbol& operator=(const Sized_symbol&);
 433
 434   // Symbol value.  Before Layout::finalize this is the offset in the
 435   // input section.  This is set to the final value during
 436   // Layout::finalize.
 437   Value_type value_;
 438   // Symbol size.
 439   Size_type symsize_;
 440 };
 441
 442 // A struct describing a symbol defined by the linker, where the value
 443 // of the symbol is defined based on an output section.  This is used
 444 // for symbols defined by the linker, like "_init_array_start".
 445
 446 struct Define_symbol_in_section
 447 {
 448   // The symbol name.
 449   const char* name;
 450   // The name of the output section with which this symbol should be
 451   // associated.  If there is no output section with that name, the
 452   // symbol will be defined as zero.
 453   const char* output_section;
 454   // The offset of the symbol within the output section.  This is an
 455   // offset from the start of the output section, unless start_at_end
 456   // is true, in which case this is an offset from the end of the
 457   // output section.
 458   uint64_t value;
 459   // The size of the symbol.
 460   uint64_t size;
 461   // The symbol type.
 462   elfcpp::STT type;
 463   // The symbol binding.
 464   elfcpp::STB binding;
 465   // The symbol visibility.
 466   elfcpp::STV visibility;
 467   // The rest of the st_other field.
 468   unsigned char nonvis;
 469   // If true, the value field is an offset from the end of the output
 470   // section.
 471   bool offset_is_from_end;
 472   // If true, this symbol is defined only if we see a reference to it.
 473   bool only_if_ref;
 474 };
 475
 476 // A struct describing a symbol defined by the linker, where the value
 477 // of the symbol is defined based on a segment.  This is used for
 478 // symbols defined by the linker, like "_end".  We describe the
 479 // segment with which the symbol should be associated by its
 480 // characteristics.  If no segment meets these characteristics, the
 481 // symbol will be defined as zero.  If there is more than one segment
 482 // which meets these characteristics, we will use the first one.
 483
 484 struct Define_symbol_in_segment
 485 {
 486   // The symbol name.
 487   const char* name;
 488   // The segment type where the symbol should be defined, typically
 489   // PT_LOAD.
 490   elfcpp::PT segment_type;
 491   // Bitmask of segment flags which must be set.
 492   elfcpp::PF segment_flags_set;
 493   // Bitmask of segment flags which must be clear.
 494   elfcpp::PF segment_flags_clear;
 495   // The offset of the symbol within the segment.  The offset is
 496   // calculated from the position set by offset_base.
 497   uint64_t value;
 498   // The size of the symbol.
 499   uint64_t size;
 500   // The symbol type.
 501   elfcpp::STT type;
 502   // The symbol binding.
 503   elfcpp::STB binding;
 504   // The symbol visibility.
 505   elfcpp::STV visibility;
 506   // The rest of the st_other field.
 507   unsigned char nonvis;
 508   // The base from which we compute the offset.
 509   Symbol::Segment_offset_base offset_base;
 510   // If true, this symbol is defined only if we see a reference to it.
 511   bool only_if_ref;
 512 };
 513
 514 // This class manages warnings.  Warnings are a GNU extension.  When
 515 // we see a section named .gnu.warning.SYM in an object file, and if
 516 // we wind using the definition of SYM from that object file, then we
 517 // will issue a warning for any relocation against SYM from a
 518 // different object file.  The text of the warning is the contents of
 519 // the section.  This is not precisely the definition used by the old
 520 // GNU linker; the old GNU linker treated an occurrence of
 521 // .gnu.warning.SYM as defining a warning symbol.  A warning symbol
 522 // would trigger a warning on any reference.  However, it was
 523 // inconsistent in that a warning in a dynamic object only triggered
 524 // if there was no definition in a regular object.  This linker is
 525 // different in that we only issue a warning if we use the symbol
 526 // definition from the same object file as the warning section.
 527
 528 class Warnings
 529 {
 530  public:
 531   Warnings()
 532     : warnings_()
 533   { }
 534
 535   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 536   void
 537   add_warning(Symbol_table* symtab, const char* name, Object* obj,
 538               unsigned int shndx);
 539
 540   // For each symbol for which we should give a warning, make a note
 541   // on the symbol.
 542   void
 543   note_warnings(Symbol_table* symtab);
 544
 545   // Issue a warning for a reference to SYM at LOCATION.
 546   void
 547   issue_warning(Symbol* sym, const std::string& location) const;
 548
 549  private:
 550   Warnings(const Warnings&);
 551   Warnings& operator=(const Warnings&);
 552
 553   // What we need to know to get the warning text.
 554   struct Warning_location
 555   {
 556     // The object the warning is in.
 557     Object* object;
 558     // The index of the warning section.
 559     unsigned int shndx;
 560     // The warning text if we have already loaded it.
 561     std::string text;
 562
 563     Warning_location()
 564       : object(NULL), shndx(0), text()
 565     { }
 566
 567     void
 568     set(Object* o, unsigned int s)
 569     {
 570       this->object = o;
 571       this->shndx = s;
 572     }
 573
 574     void
 575     set_text(const char* t, off_t l)
 576     { this->text.assign(t, l); }
 577   };
 578
 579   // A mapping from warning symbol names (canonicalized in
 580   // Symbol_table's namepool_ field) to
 581   typedef Unordered_map<const char*, Warning_location> Warning_table;
 582
 583   Warning_table warnings_;
 584 };
 585
 586 // The main linker symbol table.
 587
 588 class Symbol_table
 589 {
 590  public:
 591   Symbol_table();
 592
 593   ~Symbol_table();
 594
 595   // Add COUNT external symbols from the relocatable object OBJECT to
 596   // the symbol table.  SYMS is the symbols, SYM_NAMES is their names,
 597   // SYM_NAME_SIZE is the size of SYM_NAMES.  This sets SYMPOINTERS to
 598   // point to the symbols in the symbol table.
 599   template<int size, bool big_endian>
 600   void
 601   add_from_object(Relobj* object, const unsigned char* syms,
 602                   size_t count, const char* sym_names, size_t sym_name_size,
 603                   Symbol** sympointers);
 604
 605   // Define a special symbol.
 606   template<int size, bool big_endian>
 607   Sized_symbol<size>*
 608   define_special_symbol(Target* target, const char* name, bool only_if_ref
 609                         ACCEPT_SIZE_ENDIAN);
 610
 611   // Define a special symbol based on an Output_data.  It is a
 612   // multiple definition error if this symbol is already defined.
 613   void
 614   define_in_output_data(Target*, const char* name, Output_data*,
 615                         uint64_t value, uint64_t symsize,
 616                         elfcpp::STT type, elfcpp::STB binding,
 617                         elfcpp::STV visibility, unsigned char nonvis,
 618                         bool offset_is_from_end, bool only_if_ref);
 619
 620   // Define a special symbol based on an Output_segment.  It is a
 621   // multiple definition error if this symbol is already defined.
 622   void
 623   define_in_output_segment(Target*, const char* name, Output_segment*,
 624                            uint64_t value, uint64_t symsize,
 625                            elfcpp::STT type, elfcpp::STB binding,
 626                            elfcpp::STV visibility, unsigned char nonvis,
 627                            Symbol::Segment_offset_base, bool only_if_ref);
 628
 629   // Define a special symbol with a constant value.  It is a multiple
 630   // definition error if this symbol is already defined.
 631   void
 632   define_as_constant(Target*, const char* name, uint64_t value,
 633                      uint64_t symsize, elfcpp::STT type, elfcpp::STB binding,
 634                      elfcpp::STV visibility, unsigned char nonvis,
 635                      bool only_if_ref);
 636
 637   // Define a set of symbols in output sections.
 638   void
 639   define_symbols(const Layout*, Target*, int count,
 640                  const Define_symbol_in_section*);
 641
 642   // Define a set of symbols in output segments.
 643   void
 644   define_symbols(const Layout*, Target*, int count,
 645                  const Define_symbol_in_segment*);
 646
 647   // Look up a symbol.
 648   Symbol*
 649   lookup(const char*, const char* version = NULL) const;
 650
 651   // Return the real symbol associated with the forwarder symbol FROM.
 652   Symbol*
 653   resolve_forwards(Symbol* from) const;
 654
 655   // Return the size of the symbols in the table.
 656   int
 657   get_size() const
 658   { return this->size_; }
 659
 660   // Return the sized version of a symbol in this table.
 661   template<int size>
 662   Sized_symbol<size>*
 663   get_sized_symbol(Symbol* ACCEPT_SIZE) const;
 664
 665   template<int size>
 666   const Sized_symbol<size>*
 667   get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
 668
 669   // Return the count of undefined symbols seen.
 670   int
 671   saw_undefined() const
 672   { return this->saw_undefined_; }
 673
 674   // Allocate the common symbols
 675   void
 676   allocate_commons(const General_options&, Layout*);
 677
 678   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 679   void
 680   add_warning(const char* name, Object* obj, unsigned int shndx)
 681   { this->warnings_.add_warning(this, name, obj, shndx); }
 682
 683   // Canonicalize a symbol name for use in the hash table.
 684   const char*
 685   canonicalize_name(const char* name)
 686   { return this->namepool_.add(name, NULL); }
 687
 688   // Possibly issue a warning for a reference to SYM at LOCATION which
 689   // is in OBJ.
 690   void
 691   issue_warning(Symbol* sym, const std::string& location) const
 692   { this->warnings_.issue_warning(sym, location); }
 693
 694   // Finalize the symbol table after we have set the final addresses
 695   // of all the input sections.  This sets the final symbol values and
 696   // adds the names to *POOL.  It records the file offset OFF, and
 697   // returns the new file offset.
 698   off_t
 699   finalize(off_t, Stringpool*);
 700
 701   // Write out the global symbols.
 702   void
 703   write_globals(const Target*, const Stringpool*, Output_file*) const;
 704
 705  private:
 706   Symbol_table(const Symbol_table&);
 707   Symbol_table& operator=(const Symbol_table&);
 708
 709   // Set the size of the symbols in the table.
 710   void
 711   set_size(int size)
 712   { this->size_ = size; }
 713
 714   // Make FROM a forwarder symbol to TO.
 715   void
 716   make_forwarder(Symbol* from, Symbol* to);
 717
 718   // Add a symbol.
 719   template<int size, bool big_endian>
 720   Symbol*
 721   add_from_object(Object*, const char *name, Stringpool::Key name_key,
 722                   const char *version, Stringpool::Key version_key,
 723                   bool def, const elfcpp::Sym<size, big_endian>& sym);
 724
 725   // Resolve symbols.
 726   template<int size, bool big_endian>
 727   static void
 728   resolve(Sized_symbol<size>* to,
 729           const elfcpp::Sym<size, big_endian>& sym,
 730           Object*);
 731
 732   template<int size, bool big_endian>
 733   static void
 734   resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from
 735           ACCEPT_SIZE_ENDIAN);
 736
 737   // Define a symbol in an Output_data, sized version.
 738   template<int size>
 739   void
 740   do_define_in_output_data(Target*, const char* name, Output_data*,
 741                            typename elfcpp::Elf_types<size>::Elf_Addr value,
 742                            typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 743                            elfcpp::STT type, elfcpp::STB binding,
 744                            elfcpp::STV visibility, unsigned char nonvis,
 745                            bool offset_is_from_end, bool only_if_ref);
 746
 747   // Define a symbol in an Output_segment, sized version.
 748   template<int size>
 749   void
 750   do_define_in_output_segment(
 751     Target*, const char* name, Output_segment* os,
 752     typename elfcpp::Elf_types<size>::Elf_Addr value,
 753     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 754     elfcpp::STT type, elfcpp::STB binding,
 755     elfcpp::STV visibility, unsigned char nonvis,
 756     Symbol::Segment_offset_base offset_base, bool only_if_ref);
 757
 758   // Define a symbol as a constant, sized version.
 759   template<int size>
 760   void
 761   do_define_as_constant(
 762     Target*, const char* name,
 763     typename elfcpp::Elf_types<size>::Elf_Addr value,
 764     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 765     elfcpp::STT type, elfcpp::STB binding,
 766     elfcpp::STV visibility, unsigned char nonvis,
 767     bool only_if_ref);
 768
 769   // Allocate the common symbols, sized version.
 770   template<int size>
 771   void
 772   do_allocate_commons(const General_options&, Layout*);
 773
 774   // Finalize symbols specialized for size.
 775   template<int size>
 776   off_t
 777   sized_finalize(off_t, Stringpool*);
 778
 779   // Write globals specialized for size and endianness.
 780   template<int size, bool big_endian>
 781   void
 782   sized_write_globals(const Target*, const Stringpool*, Output_file*) const;
 783
 784   // The type of the symbol hash table.
 785
 786   typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
 787
 788   struct Symbol_table_hash
 789   {
 790     size_t
 791     operator()(const Symbol_table_key&) const;
 792   };
 793
 794   struct Symbol_table_eq
 795   {
 796     bool
 797     operator()(const Symbol_table_key&, const Symbol_table_key&) const;
 798   };
 799
 800   typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
 801                         Symbol_table_eq> Symbol_table_type;
 802
 803   // The type of the list of common symbols.
 804
 805   typedef std::vector<Symbol*> Commons_type;
 806
 807   // The size of the symbols in the symbol table (32 or 64).
 808   int size_;
 809
 810   // We increment this every time we see a new undefined symbol, for
 811   // use in archive groups.
 812   int saw_undefined_;
 813
 814   // The file offset within the output symtab section where we should
 815   // write the table.
 816   off_t offset_;
 817
 818   // The number of global symbols we want to write out.
 819   size_t output_count_;
 820
 821   // The symbol hash table.
 822   Symbol_table_type table_;
 823
 824   // A pool of symbol names.  This is used for all global symbols.
 825   // Entries in the hash table point into this pool.
 826   Stringpool namepool_;
 827
 828   // Forwarding symbols.
 829   Unordered_map<Symbol*, Symbol*> forwarders_;
 830
 831   // We don't expect there to be very many common symbols, so we keep
 832   // a list of them.  When we find a common symbol we add it to this
 833   // list.  It is possible that by the time we process the list the
 834   // symbol is no longer a common symbol.  It may also have become a
 835   // forwarder.
 836   Commons_type commons_;
 837
 838   // Manage symbol warnings.
 839   Warnings warnings_;
 840 };
 841
 842 // We inline get_sized_symbol for efficiency.
 843
 844 template<int size>
 845 Sized_symbol<size>*
 846 Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const
 847 {
 848   assert(size == this->get_size());
 849   return static_cast<Sized_symbol<size>*>(sym);
 850 }
 851
 852 template<int size>
 853 const Sized_symbol<size>*
 854 Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const
 855 {
 856   assert(size == this->get_size());
 857   return static_cast<const Sized_symbol<size>*>(sym);
 858 }
 859
 860 } // End namespace gold.
 861
 862 #endif // !defined(GOLD_SYMTAB_H)