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