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
  10 #include "elfcpp.h"
  11 #include "stringpool.h"
  12 #include "object.h"
  13
  14 #ifndef GOLD_SYMTAB_H
  15 #define GOLD_SYMTAB_H
  16
  17 namespace gold
  18 {
  19
  20 class Object;
  21 class Relobj;
  22 template<int size, bool big_endian>
  23 class Sized_relobj;
  24 class Dynobj;
  25 template<int size, bool big_endian>
  26 class Sized_dynobj;
  27 class Versions;
  28 class Output_data;
  29 class Output_section;
  30 class Output_segment;
  31 class Output_file;
  32 class Target;
  33
  34 // The base class of an entry in the symbol table.  The symbol table
  35 // can have a lot of entries, so we don't want this class to big.
  36 // Size dependent fields can be found in the template class
  37 // Sized_symbol.  Targets may support their own derived classes.
  38
  39 class Symbol
  40 {
  41  public:
  42   // Because we want the class to be small, we don't use any virtual
  43   // functions.  But because symbols can be defined in different
  44   // places, we need to classify them.  This enum is the different
  45   // sources of symbols we support.
  46   enum Source
  47   {
  48     // Symbol defined in a relocatable or dynamic input file--this is
  49     // the most common case.
  50     FROM_OBJECT,
  51     // Symbol defined in an Output_data, a special section created by
  52     // the target.
  53     IN_OUTPUT_DATA,
  54     // Symbol defined in an Output_segment, with no associated
  55     // section.
  56     IN_OUTPUT_SEGMENT,
  57     // Symbol value is constant.
  58     CONSTANT
  59   };
  60
  61   // When the source is IN_OUTPUT_SEGMENT, we need to describe what
  62   // the offset means.
  63   enum Segment_offset_base
  64   {
  65     // From the start of the segment.
  66     SEGMENT_START,
  67     // From the end of the segment.
  68     SEGMENT_END,
  69     // From the filesz of the segment--i.e., after the loaded bytes
  70     // but before the bytes which are allocated but zeroed.
  71     SEGMENT_BSS
  72   };
  73
  74   // Return the symbol name.
  75   const char*
  76   name() const
  77   { return this->name_; }
  78
  79   // Return the symbol version.  This will return NULL for an
  80   // unversioned symbol.
  81   const char*
  82   version() const
  83   { return this->version_; }
  84
  85   // Return the symbol source.
  86   Source
  87   source() const
  88   { return this->source_; }
  89
  90   // Return the object with which this symbol is associated.
  91   Object*
  92   object() const
  93   {
  94     gold_assert(this->source_ == FROM_OBJECT);
  95     return this->u_.from_object.object;
  96   }
  97
  98   // Return the index of the section in the input relocatable or
  99   // dynamic object file.
 100   unsigned int
 101   shndx() const
 102   {
 103     gold_assert(this->source_ == FROM_OBJECT);
 104     return this->u_.from_object.shndx;
 105   }
 106
 107   // Return the output data section with which this symbol is
 108   // associated, if the symbol was specially defined with respect to
 109   // an output data section.
 110   Output_data*
 111   output_data() const
 112   {
 113     gold_assert(this->source_ == IN_OUTPUT_DATA);
 114     return this->u_.in_output_data.output_data;
 115   }
 116
 117   // If this symbol was defined with respect to an output data
 118   // section, return whether the value is an offset from end.
 119   bool
 120   offset_is_from_end() const
 121   {
 122     gold_assert(this->source_ == IN_OUTPUT_DATA);
 123     return this->u_.in_output_data.offset_is_from_end;
 124   }
 125
 126   // Return the output segment with which this symbol is associated,
 127   // if the symbol was specially defined with respect to an output
 128   // segment.
 129   Output_segment*
 130   output_segment() const
 131   {
 132     gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
 133     return this->u_.in_output_segment.output_segment;
 134   }
 135
 136   // If this symbol was defined with respect to an output segment,
 137   // return the offset base.
 138   Segment_offset_base
 139   offset_base() const
 140   {
 141     gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
 142     return this->u_.in_output_segment.offset_base;
 143   }
 144
 145   // Return the symbol binding.
 146   elfcpp::STB
 147   binding() const
 148   { return this->binding_; }
 149
 150   // Return the symbol type.
 151   elfcpp::STT
 152   type() const
 153   { return this->type_; }
 154
 155   // Return the symbol visibility.
 156   elfcpp::STV
 157   visibility() const
 158   { return this->visibility_; }
 159
 160   // Return the non-visibility part of the st_other field.
 161   unsigned char
 162   nonvis() const
 163   { return this->nonvis_; }
 164
 165   // Return whether this symbol is a forwarder.  This will never be
 166   // true of a symbol found in the hash table, but may be true of
 167   // symbol pointers attached to object files.
 168   bool
 169   is_forwarder() const
 170   { return this->is_forwarder_; }
 171
 172   // Mark this symbol as a forwarder.
 173   void
 174   set_forwarder()
 175   { this->is_forwarder_ = true; }
 176
 177   // Return whether this symbol needs an entry in the dynamic symbol
 178   // table.
 179   bool
 180   needs_dynsym_entry() const
 181   { return this->needs_dynsym_entry_; }
 182
 183   // Mark this symbol as needing an entry in the dynamic symbol table.
 184   void
 185   set_needs_dynsym_entry()
 186   { this->needs_dynsym_entry_ = true; }
 187
 188   // Return whether this symbol has been seen in a regular object.
 189   bool
 190   in_reg() const
 191   { return this->in_reg_; }
 192
 193   // Mark this symbol as having been seen in a regular object.
 194   void
 195   set_in_reg()
 196   { this->in_reg_ = true; }
 197
 198   // Mark this symbol as having been seen in a dynamic object.
 199   void
 200   set_in_dyn()
 201   { this->in_dyn_ = true; }
 202
 203   // Return the index of this symbol in the output file symbol table.
 204   // A value of -1U means that this symbol is not going into the
 205   // output file.  This starts out as zero, and is set to a non-zero
 206   // value by Symbol_table::finalize.  It is an error to ask for the
 207   // symbol table index before it has been set.
 208   unsigned int
 209   symtab_index() const
 210   {
 211     gold_assert(this->symtab_index_ != 0);
 212     return this->symtab_index_;
 213   }
 214
 215   // Set the index of the symbol in the output file symbol table.
 216   void
 217   set_symtab_index(unsigned int index)
 218   {
 219     gold_assert(index != 0);
 220     this->symtab_index_ = index;
 221   }
 222
 223   // Return whether this symbol already has an index in the output
 224   // file symbol table.
 225   bool
 226   has_symtab_index() const
 227   { return this->symtab_index_ != 0; }
 228
 229   // Return the index of this symbol in the dynamic symbol table.  A
 230   // value of -1U means that this symbol is not going into the dynamic
 231   // symbol table.  This starts out as zero, and is set to a non-zero
 232   // during Layout::finalize.  It is an error to ask for the dynamic
 233   // symbol table index before it has been set.
 234   unsigned int
 235   dynsym_index() const
 236   {
 237     gold_assert(this->dynsym_index_ != 0);
 238     return this->dynsym_index_;
 239   }
 240
 241   // Set the index of the symbol in the dynamic symbol table.
 242   void
 243   set_dynsym_index(unsigned int index)
 244   {
 245     gold_assert(index != 0);
 246     this->dynsym_index_ = index;
 247   }
 248
 249   // Return whether this symbol already has an index in the dynamic
 250   // symbol table.
 251   bool
 252   has_dynsym_index() const
 253   { return this->dynsym_index_ != 0; }
 254
 255   // Return whether this symbol has an entry in the GOT section.
 256   bool
 257   has_got_offset() const
 258   { return this->has_got_offset_; }
 259
 260   // Return the offset into the GOT section of this symbol.
 261   unsigned int
 262   got_offset() const
 263   {
 264     gold_assert(this->has_got_offset());
 265     return this->got_offset_;
 266   }
 267
 268   // Set the GOT offset of this symbol.
 269   void
 270   set_got_offset(unsigned int got_offset)
 271   {
 272     this->has_got_offset_ = true;
 273     this->got_offset_ = got_offset;
 274   }
 275
 276   // Return whether this symbol has an entry in the PLT section.
 277   bool
 278   has_plt_offset() const
 279   { return this->has_plt_offset_; }
 280
 281   // Return the offset into the PLT section of this symbol.
 282   unsigned int
 283   plt_offset() const
 284   {
 285     gold_assert(this->has_plt_offset());
 286     return this->plt_offset_;
 287   }
 288
 289   // Set the PLT offset of this symbol.
 290   void
 291   set_plt_offset(unsigned int plt_offset)
 292   {
 293     this->has_plt_offset_ = true;
 294     this->plt_offset_ = plt_offset;
 295   }
 296
 297   // Return true if the final value of this symbol is known at link
 298   // time.
 299   bool
 300   final_value_is_known(const General_options* options) const
 301   {
 302     if (options->is_shared())
 303       return false;
 304     return this->source_ != FROM_OBJECT || !this->object()->is_dynamic();
 305   }
 306
 307   // Return whether this is a defined symbol (not undefined or
 308   // common).
 309   bool
 310   is_defined() const
 311   {
 312     return (this->source_ != FROM_OBJECT
 313             || (this->shndx() != elfcpp::SHN_UNDEF
 314                 && this->shndx() != elfcpp::SHN_COMMON));
 315   }
 316
 317   // Return true if this symbol is from a dynamic object.
 318   bool
 319   is_from_dynobj() const
 320   {
 321     return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
 322   }
 323
 324   // Return whether this is an undefined symbol.
 325   bool
 326   is_undefined() const
 327   {
 328     return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF;
 329   }
 330
 331   // Return whether this is a common symbol.
 332   bool
 333   is_common() const
 334   {
 335     return (this->source_ == FROM_OBJECT
 336             && (this->shndx() == elfcpp::SHN_COMMON
 337                 || this->type_ == elfcpp::STT_COMMON));
 338   }
 339
 340   // Return whether there should be a warning for references to this
 341   // symbol.
 342   bool
 343   has_warning() const
 344   { return this->has_warning_; }
 345
 346   // Mark this symbol as having a warning.
 347   void
 348   set_has_warning()
 349   { this->has_warning_ = true; }
 350
 351  protected:
 352   // Instances of this class should always be created at a specific
 353   // size.
 354   Symbol()
 355   { memset(this, 0, sizeof *this); }
 356
 357   // Initialize the general fields.
 358   void
 359   init_fields(const char* name, const char* version,
 360               elfcpp::STT type, elfcpp::STB binding,
 361               elfcpp::STV visibility, unsigned char nonvis);
 362
 363   // Initialize fields from an ELF symbol in OBJECT.
 364   template<int size, bool big_endian>
 365   void
 366   init_base(const char *name, const char* version, Object* object,
 367             const elfcpp::Sym<size, big_endian>&);
 368
 369   // Initialize fields for an Output_data.
 370   void
 371   init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
 372             elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
 373
 374   // Initialize fields for an Output_segment.
 375   void
 376   init_base(const char* name, Output_segment* os, elfcpp::STT type,
 377             elfcpp::STB binding, elfcpp::STV visibility,
 378             unsigned char nonvis, Segment_offset_base offset_base);
 379
 380   // Initialize fields for a constant.
 381   void
 382   init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
 383             elfcpp::STV visibility, unsigned char nonvis);
 384
 385   // Override existing symbol.
 386   template<int size, bool big_endian>
 387   void
 388   override_base(const elfcpp::Sym<size, big_endian>&, Object* object,
 389                 const char* version);
 390
 391  private:
 392   Symbol(const Symbol&);
 393   Symbol& operator=(const Symbol&);
 394
 395   // Symbol name (expected to point into a Stringpool).
 396   const char* name_;
 397   // Symbol version (expected to point into a Stringpool).  This may
 398   // be NULL.
 399   const char* version_;
 400
 401   union
 402   {
 403     // This struct is used if SOURCE_ == FROM_OBJECT.
 404     struct
 405     {
 406       // Object in which symbol is defined, or in which it was first
 407       // seen.
 408       Object* object;
 409       // Section number in object_ in which symbol is defined.
 410       unsigned int shndx;
 411     } from_object;
 412
 413     // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
 414     struct
 415     {
 416       // Output_data in which symbol is defined.  Before
 417       // Layout::finalize the symbol's value is an offset within the
 418       // Output_data.
 419       Output_data* output_data;
 420       // True if the offset is from the end, false if the offset is
 421       // from the beginning.
 422       bool offset_is_from_end;
 423     } in_output_data;
 424
 425     // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
 426     struct
 427     {
 428       // Output_segment in which the symbol is defined.  Before
 429       // Layout::finalize the symbol's value is an offset.
 430       Output_segment* output_segment;
 431       // The base to use for the offset before Layout::finalize.
 432       Segment_offset_base offset_base;
 433     } in_output_segment;
 434   } u_;
 435
 436   // The index of this symbol in the output file.  If the symbol is
 437   // not going into the output file, this value is -1U.  This field
 438   // starts as always holding zero.  It is set to a non-zero value by
 439   // Symbol_table::finalize.
 440   unsigned int symtab_index_;
 441
 442   // The index of this symbol in the dynamic symbol table.  If the
 443   // symbol is not going into the dynamic symbol table, this value is
 444   // -1U.  This field starts as always holding zero.  It is set to a
 445   // non-zero value during Layout::finalize.
 446   unsigned int dynsym_index_;
 447
 448   // If this symbol has an entry in the GOT section (has_got_offset_
 449   // is true), this is the offset from the start of the GOT section.
 450   unsigned int got_offset_;
 451
 452   // If this symbol has an entry in the PLT section (has_plt_offset_
 453   // is true), then this is the offset from the start of the PLT
 454   // section.
 455   unsigned int plt_offset_;
 456
 457   // Symbol type.
 458   elfcpp::STT type_ : 4;
 459   // Symbol binding.
 460   elfcpp::STB binding_ : 4;
 461   // Symbol visibility.
 462   elfcpp::STV visibility_ : 2;
 463   // Rest of symbol st_other field.
 464   unsigned int nonvis_ : 6;
 465   // The type of symbol.
 466   Source source_ : 3;
 467   // True if this symbol always requires special target-specific
 468   // handling.
 469   bool is_target_special_ : 1;
 470   // True if this is the default version of the symbol.
 471   bool is_def_ : 1;
 472   // True if this symbol really forwards to another symbol.  This is
 473   // used when we discover after the fact that two different entries
 474   // in the hash table really refer to the same symbol.  This will
 475   // never be set for a symbol found in the hash table, but may be set
 476   // for a symbol found in the list of symbols attached to an Object.
 477   // It forwards to the symbol found in the forwarders_ map of
 478   // Symbol_table.
 479   bool is_forwarder_ : 1;
 480   // True if this symbol needs to be in the dynamic symbol table.
 481   bool needs_dynsym_entry_ : 1;
 482   // True if we've seen this symbol in a regular object.
 483   bool in_reg_ : 1;
 484   // True if we've seen this symbol in a dynamic object.
 485   bool in_dyn_ : 1;
 486   // True if the symbol has an entry in the GOT section.
 487   bool has_got_offset_ : 1;
 488   // True if the symbol has an entry in the PLT section.
 489   bool has_plt_offset_ : 1;
 490   // True if there is a warning for this symbol.
 491   bool has_warning_ : 1;
 492 };
 493
 494 // The parts of a symbol which are size specific.  Using a template
 495 // derived class like this helps us use less space on a 32-bit system.
 496
 497 template<int size>
 498 class Sized_symbol : public Symbol
 499 {
 500  public:
 501   typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
 502   typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
 503
 504   Sized_symbol()
 505   { }
 506
 507   // Initialize fields from an ELF symbol in OBJECT.
 508   template<bool big_endian>
 509   void
 510   init(const char *name, const char* version, Object* object,
 511        const elfcpp::Sym<size, big_endian>&);
 512
 513   // Initialize fields for an Output_data.
 514   void
 515   init(const char* name, Output_data*, Value_type value, Size_type symsize,
 516        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 517        bool offset_is_from_end);
 518
 519   // Initialize fields for an Output_segment.
 520   void
 521   init(const char* name, Output_segment*, Value_type value, Size_type symsize,
 522        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 523        Segment_offset_base offset_base);
 524
 525   // Initialize fields for a constant.
 526   void
 527   init(const char* name, Value_type value, Size_type symsize,
 528        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
 529
 530   // Override existing symbol.
 531   template<bool big_endian>
 532   void
 533   override(const elfcpp::Sym<size, big_endian>&, Object* object,
 534            const char* version);
 535
 536   // Return the symbol's value.
 537   Value_type
 538   value() const
 539   { return this->value_; }
 540
 541   // Return the symbol's size (we can't call this 'size' because that
 542   // is a template parameter).
 543   Size_type
 544   symsize() const
 545   { return this->symsize_; }
 546
 547   // Set the symbol size.  This is used when resolving common symbols.
 548   void
 549   set_symsize(Size_type symsize)
 550   { this->symsize_ = symsize; }
 551
 552   // Set the symbol value.  This is called when we store the final
 553   // values of the symbols into the symbol table.
 554   void
 555   set_value(Value_type value)
 556   { this->value_ = value; }
 557
 558  private:
 559   Sized_symbol(const Sized_symbol&);
 560   Sized_symbol& operator=(const Sized_symbol&);
 561
 562   // Symbol value.  Before Layout::finalize this is the offset in the
 563   // input section.  This is set to the final value during
 564   // Layout::finalize.
 565   Value_type value_;
 566   // Symbol size.
 567   Size_type symsize_;
 568 };
 569
 570 // A struct describing a symbol defined by the linker, where the value
 571 // of the symbol is defined based on an output section.  This is used
 572 // for symbols defined by the linker, like "_init_array_start".
 573
 574 struct Define_symbol_in_section
 575 {
 576   // The symbol name.
 577   const char* name;
 578   // The name of the output section with which this symbol should be
 579   // associated.  If there is no output section with that name, the
 580   // symbol will be defined as zero.
 581   const char* output_section;
 582   // The offset of the symbol within the output section.  This is an
 583   // offset from the start of the output section, unless start_at_end
 584   // is true, in which case this is an offset from the end of the
 585   // output section.
 586   uint64_t value;
 587   // The size of the symbol.
 588   uint64_t size;
 589   // The symbol type.
 590   elfcpp::STT type;
 591   // The symbol binding.
 592   elfcpp::STB binding;
 593   // The symbol visibility.
 594   elfcpp::STV visibility;
 595   // The rest of the st_other field.
 596   unsigned char nonvis;
 597   // If true, the value field is an offset from the end of the output
 598   // section.
 599   bool offset_is_from_end;
 600   // If true, this symbol is defined only if we see a reference to it.
 601   bool only_if_ref;
 602 };
 603
 604 // A struct describing a symbol defined by the linker, where the value
 605 // of the symbol is defined based on a segment.  This is used for
 606 // symbols defined by the linker, like "_end".  We describe the
 607 // segment with which the symbol should be associated by its
 608 // characteristics.  If no segment meets these characteristics, the
 609 // symbol will be defined as zero.  If there is more than one segment
 610 // which meets these characteristics, we will use the first one.
 611
 612 struct Define_symbol_in_segment
 613 {
 614   // The symbol name.
 615   const char* name;
 616   // The segment type where the symbol should be defined, typically
 617   // PT_LOAD.
 618   elfcpp::PT segment_type;
 619   // Bitmask of segment flags which must be set.
 620   elfcpp::PF segment_flags_set;
 621   // Bitmask of segment flags which must be clear.
 622   elfcpp::PF segment_flags_clear;
 623   // The offset of the symbol within the segment.  The offset is
 624   // calculated from the position set by offset_base.
 625   uint64_t value;
 626   // The size of the symbol.
 627   uint64_t size;
 628   // The symbol type.
 629   elfcpp::STT type;
 630   // The symbol binding.
 631   elfcpp::STB binding;
 632   // The symbol visibility.
 633   elfcpp::STV visibility;
 634   // The rest of the st_other field.
 635   unsigned char nonvis;
 636   // The base from which we compute the offset.
 637   Symbol::Segment_offset_base offset_base;
 638   // If true, this symbol is defined only if we see a reference to it.
 639   bool only_if_ref;
 640 };
 641
 642 // This class manages warnings.  Warnings are a GNU extension.  When
 643 // we see a section named .gnu.warning.SYM in an object file, and if
 644 // we wind using the definition of SYM from that object file, then we
 645 // will issue a warning for any relocation against SYM from a
 646 // different object file.  The text of the warning is the contents of
 647 // the section.  This is not precisely the definition used by the old
 648 // GNU linker; the old GNU linker treated an occurrence of
 649 // .gnu.warning.SYM as defining a warning symbol.  A warning symbol
 650 // would trigger a warning on any reference.  However, it was
 651 // inconsistent in that a warning in a dynamic object only triggered
 652 // if there was no definition in a regular object.  This linker is
 653 // different in that we only issue a warning if we use the symbol
 654 // definition from the same object file as the warning section.
 655
 656 class Warnings
 657 {
 658  public:
 659   Warnings()
 660     : warnings_()
 661   { }
 662
 663   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 664   void
 665   add_warning(Symbol_table* symtab, const char* name, Object* obj,
 666               unsigned int shndx);
 667
 668   // For each symbol for which we should give a warning, make a note
 669   // on the symbol.
 670   void
 671   note_warnings(Symbol_table* symtab);
 672
 673   // Issue a warning for a reference to SYM at LOCATION.
 674   void
 675   issue_warning(const Symbol* sym, const std::string& location) const;
 676
 677  private:
 678   Warnings(const Warnings&);
 679   Warnings& operator=(const Warnings&);
 680
 681   // What we need to know to get the warning text.
 682   struct Warning_location
 683   {
 684     // The object the warning is in.
 685     Object* object;
 686     // The index of the warning section.
 687     unsigned int shndx;
 688     // The warning text if we have already loaded it.
 689     std::string text;
 690
 691     Warning_location()
 692       : object(NULL), shndx(0), text()
 693     { }
 694
 695     void
 696     set(Object* o, unsigned int s)
 697     {
 698       this->object = o;
 699       this->shndx = s;
 700     }
 701
 702     void
 703     set_text(const char* t, off_t l)
 704     { this->text.assign(t, l); }
 705   };
 706
 707   // A mapping from warning symbol names (canonicalized in
 708   // Symbol_table's namepool_ field) to
 709   typedef Unordered_map<const char*, Warning_location> Warning_table;
 710
 711   Warning_table warnings_;
 712 };
 713
 714 // The main linker symbol table.
 715
 716 class Symbol_table
 717 {
 718  public:
 719   Symbol_table();
 720
 721   ~Symbol_table();
 722
 723   // Add COUNT external symbols from the relocatable object RELOBJ to
 724   // the symbol table.  SYMS is the symbols, SYM_NAMES is their names,
 725   // SYM_NAME_SIZE is the size of SYM_NAMES.  This sets SYMPOINTERS to
 726   // point to the symbols in the symbol table.
 727   template<int size, bool big_endian>
 728   void
 729   add_from_relobj(Sized_relobj<size, big_endian>* relobj,
 730                   const unsigned char* syms, size_t count,
 731                   const char* sym_names, size_t sym_name_size,
 732                   Symbol** sympointers);
 733
 734   // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
 735   // symbol table.  SYMS is the symbols.  SYM_NAMES is their names.
 736   // SYM_NAME_SIZE is the size of SYM_NAMES.  The other parameters are
 737   // symbol version data.
 738   template<int size, bool big_endian>
 739   void
 740   add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
 741                   const unsigned char* syms, size_t count,
 742                   const char* sym_names, size_t sym_name_size,
 743                   const unsigned char* versym, size_t versym_size,
 744                   const std::vector<const char*>*);
 745
 746   // Define a special symbol based on an Output_data.  It is a
 747   // multiple definition error if this symbol is already defined.
 748   Symbol*
 749   define_in_output_data(const Target*, const char* name, const char* version,
 750                         Output_data*, uint64_t value, uint64_t symsize,
 751                         elfcpp::STT type, elfcpp::STB binding,
 752                         elfcpp::STV visibility, unsigned char nonvis,
 753                         bool offset_is_from_end, bool only_if_ref);
 754
 755   // Define a special symbol based on an Output_segment.  It is a
 756   // multiple definition error if this symbol is already defined.
 757   Symbol*
 758   define_in_output_segment(const Target*, const char* name,
 759                            const char* version, Output_segment*,
 760                            uint64_t value, uint64_t symsize,
 761                            elfcpp::STT type, elfcpp::STB binding,
 762                            elfcpp::STV visibility, unsigned char nonvis,
 763                            Symbol::Segment_offset_base, bool only_if_ref);
 764
 765   // Define a special symbol with a constant value.  It is a multiple
 766   // definition error if this symbol is already defined.
 767   Symbol*
 768   define_as_constant(const Target*, const char* name, const char* version,
 769                      uint64_t value, uint64_t symsize, elfcpp::STT type,
 770                      elfcpp::STB binding, elfcpp::STV visibility,
 771                      unsigned char nonvis, bool only_if_ref);
 772
 773   // Define a set of symbols in output sections.
 774   void
 775   define_symbols(const Layout*, const Target*, int count,
 776                  const Define_symbol_in_section*);
 777
 778   // Define a set of symbols in output segments.
 779   void
 780   define_symbols(const Layout*, const Target*, int count,
 781                  const Define_symbol_in_segment*);
 782
 783   // Look up a symbol.
 784   Symbol*
 785   lookup(const char*, const char* version = NULL) const;
 786
 787   // Return the real symbol associated with the forwarder symbol FROM.
 788   Symbol*
 789   resolve_forwards(const Symbol* from) const;
 790
 791   // Return the bitsize (32 or 64) of the symbols in the table.
 792   int
 793   get_size() const
 794   { return this->size_; }
 795
 796   // Return the sized version of a symbol in this table.
 797   template<int size>
 798   Sized_symbol<size>*
 799   get_sized_symbol(Symbol* ACCEPT_SIZE) const;
 800
 801   template<int size>
 802   const Sized_symbol<size>*
 803   get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
 804
 805   // Return the count of undefined symbols seen.
 806   int
 807   saw_undefined() const
 808   { return this->saw_undefined_; }
 809
 810   // Allocate the common symbols
 811   void
 812   allocate_commons(const General_options&, Layout*);
 813
 814   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 815   void
 816   add_warning(const char* name, Object* obj, unsigned int shndx)
 817   { this->warnings_.add_warning(this, name, obj, shndx); }
 818
 819   // Canonicalize a symbol name for use in the hash table.
 820   const char*
 821   canonicalize_name(const char* name)
 822   { return this->namepool_.add(name, NULL); }
 823
 824   // Possibly issue a warning for a reference to SYM at LOCATION which
 825   // is in OBJ.
 826   void
 827   issue_warning(const Symbol* sym, const std::string& location) const
 828   { this->warnings_.issue_warning(sym, location); }
 829
 830   // Set the dynamic symbol indexes.  INDEX is the index of the first
 831   // global dynamic symbol.  Pointers to the symbols are stored into
 832   // the vector.  The names are stored into the Stringpool.  This
 833   // returns an updated dynamic symbol index.
 834   unsigned int
 835   set_dynsym_indexes(const General_options*, const Target*, unsigned int index,
 836                      std::vector<Symbol*>*, Stringpool*, Versions*);
 837
 838   // Finalize the symbol table after we have set the final addresses
 839   // of all the input sections.  This sets the final symbol indexes,
 840   // values and adds the names to *POOL.  INDEX is the index of the
 841   // first global symbol.  OFF is the file offset of the global symbol
 842   // table, DYNOFF is the offset of the globals in the dynamic symbol
 843   // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
 844   // symbol, and DYNCOUNT is the number of global dynamic symbols.
 845   // This records the parameters, and returns the new file offset.
 846   off_t
 847   finalize(unsigned int index, off_t off, off_t dynoff,
 848            size_t dyn_global_index, size_t dyncount, Stringpool* pool);
 849
 850   // Write out the global symbols.
 851   void
 852   write_globals(const Target*, const Stringpool*, const Stringpool*,
 853                 Output_file*) const;
 854
 855   // Write out a section symbol.  Return the updated offset.
 856   void
 857   write_section_symbol(const Target*, const Output_section*, Output_file*,
 858                        off_t) const;
 859
 860  private:
 861   Symbol_table(const Symbol_table&);
 862   Symbol_table& operator=(const Symbol_table&);
 863
 864   // Set the size (32 or 64) of the symbols in the table.
 865   void
 866   set_size(int size)
 867   { this->size_ = size; }
 868
 869   // Make FROM a forwarder symbol to TO.
 870   void
 871   make_forwarder(Symbol* from, Symbol* to);
 872
 873   // Add a symbol.
 874   template<int size, bool big_endian>
 875   Symbol*
 876   add_from_object(Object*, const char *name, Stringpool::Key name_key,
 877                   const char *version, Stringpool::Key version_key,
 878                   bool def, const elfcpp::Sym<size, big_endian>& sym);
 879
 880   // Resolve symbols.
 881   template<int size, bool big_endian>
 882   static void
 883   resolve(Sized_symbol<size>* to,
 884           const elfcpp::Sym<size, big_endian>& sym,
 885           Object*, const char* version);
 886
 887   template<int size, bool big_endian>
 888   static void
 889   resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
 890           const char* version ACCEPT_SIZE_ENDIAN);
 891
 892   // Define a special symbol.
 893   template<int size, bool big_endian>
 894   Sized_symbol<size>*
 895   define_special_symbol(const Target* target, const char* name,
 896                         const char* version, bool only_if_ref
 897                         ACCEPT_SIZE_ENDIAN);
 898
 899   // Define a symbol in an Output_data, sized version.
 900   template<int size>
 901   Sized_symbol<size>*
 902   do_define_in_output_data(const Target*, const char* name,
 903                            const char* version, Output_data*,
 904                            typename elfcpp::Elf_types<size>::Elf_Addr value,
 905                            typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 906                            elfcpp::STT type, elfcpp::STB binding,
 907                            elfcpp::STV visibility, unsigned char nonvis,
 908                            bool offset_is_from_end, bool only_if_ref);
 909
 910   // Define a symbol in an Output_segment, sized version.
 911   template<int size>
 912   Sized_symbol<size>*
 913   do_define_in_output_segment(
 914     const Target*, const char* name, const char* version, Output_segment* os,
 915     typename elfcpp::Elf_types<size>::Elf_Addr value,
 916     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 917     elfcpp::STT type, elfcpp::STB binding,
 918     elfcpp::STV visibility, unsigned char nonvis,
 919     Symbol::Segment_offset_base offset_base, bool only_if_ref);
 920
 921   // Define a symbol as a constant, sized version.
 922   template<int size>
 923   Sized_symbol<size>*
 924   do_define_as_constant(
 925     const Target*, const char* name, const char* version,
 926     typename elfcpp::Elf_types<size>::Elf_Addr value,
 927     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 928     elfcpp::STT type, elfcpp::STB binding,
 929     elfcpp::STV visibility, unsigned char nonvis,
 930     bool only_if_ref);
 931
 932   // Allocate the common symbols, sized version.
 933   template<int size>
 934   void
 935   do_allocate_commons(const General_options&, Layout*);
 936
 937   // Finalize symbols specialized for size.
 938   template<int size>
 939   off_t
 940   sized_finalize(unsigned int, off_t, Stringpool*);
 941
 942   // Write globals specialized for size and endianness.
 943   template<int size, bool big_endian>
 944   void
 945   sized_write_globals(const Target*, const Stringpool*, const Stringpool*,
 946                       Output_file*) const;
 947
 948   // Write out a symbol to P.
 949   template<int size, bool big_endian>
 950   void
 951   sized_write_symbol(Sized_symbol<size>*, unsigned int shndx,
 952                      const Stringpool*, unsigned char* p
 953                      ACCEPT_SIZE_ENDIAN) const;
 954
 955   // Write out a section symbol, specialized for size and endianness.
 956   template<int size, bool big_endian>
 957   void
 958   sized_write_section_symbol(const Output_section*, Output_file*, off_t) const;
 959
 960   // The type of the symbol hash table.
 961
 962   typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
 963
 964   struct Symbol_table_hash
 965   {
 966     size_t
 967     operator()(const Symbol_table_key&) const;
 968   };
 969
 970   struct Symbol_table_eq
 971   {
 972     bool
 973     operator()(const Symbol_table_key&, const Symbol_table_key&) const;
 974   };
 975
 976   typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
 977                         Symbol_table_eq> Symbol_table_type;
 978
 979   // The type of the list of common symbols.
 980
 981   typedef std::vector<Symbol*> Commons_type;
 982
 983   // The size of the symbols in the symbol table (32 or 64).
 984   int size_;
 985
 986   // We increment this every time we see a new undefined symbol, for
 987   // use in archive groups.
 988   int saw_undefined_;
 989
 990   // The index of the first global symbol in the output file.
 991   unsigned int first_global_index_;
 992
 993   // The file offset within the output symtab section where we should
 994   // write the table.
 995   off_t offset_;
 996
 997   // The number of global symbols we want to write out.
 998   size_t output_count_;
 999
1000   // The file offset of the global dynamic symbols, or 0 if none.
1001   off_t dynamic_offset_;
1002
1003   // The index of the first global dynamic symbol.
1004   unsigned int first_dynamic_global_index_;
1005
1006   // The number of global dynamic symbols, or 0 if none.
1007   off_t dynamic_count_;
1008
1009   // The symbol hash table.
1010   Symbol_table_type table_;
1011
1012   // A pool of symbol names.  This is used for all global symbols.
1013   // Entries in the hash table point into this pool.
1014   Stringpool namepool_;
1015
1016   // Forwarding symbols.
1017   Unordered_map<const Symbol*, Symbol*> forwarders_;
1018
1019   // We don't expect there to be very many common symbols, so we keep
1020   // a list of them.  When we find a common symbol we add it to this
1021   // list.  It is possible that by the time we process the list the
1022   // symbol is no longer a common symbol.  It may also have become a
1023   // forwarder.
1024   Commons_type commons_;
1025
1026   // Manage symbol warnings.
1027   Warnings warnings_;
1028 };
1029
1030 // We inline get_sized_symbol for efficiency.
1031
1032 template<int size>
1033 Sized_symbol<size>*
1034 Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const
1035 {
1036   gold_assert(size == this->get_size());
1037   return static_cast<Sized_symbol<size>*>(sym);
1038 }
1039
1040 template<int size>
1041 const Sized_symbol<size>*
1042 Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const
1043 {
1044   gold_assert(size == this->get_size());
1045   return static_cast<const Sized_symbol<size>*>(sym);
1046 }
1047
1048 } // End namespace gold.
1049
1050 #endif // !defined(GOLD_SYMTAB_H)