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   // Return whether this symbol has been seen in a dynamic object.
 199   bool
 200   in_dyn() const
 201   { return this->in_dyn_; }
 202
 203   // Mark this symbol as having been seen in a dynamic object.
 204   void
 205   set_in_dyn()
 206   { this->in_dyn_ = true; }
 207
 208   // Return the index of this symbol in the output file symbol table.
 209   // A value of -1U means that this symbol is not going into the
 210   // output file.  This starts out as zero, and is set to a non-zero
 211   // value by Symbol_table::finalize.  It is an error to ask for the
 212   // symbol table index before it has been set.
 213   unsigned int
 214   symtab_index() const
 215   {
 216     gold_assert(this->symtab_index_ != 0);
 217     return this->symtab_index_;
 218   }
 219
 220   // Set the index of the symbol in the output file symbol table.
 221   void
 222   set_symtab_index(unsigned int index)
 223   {
 224     gold_assert(index != 0);
 225     this->symtab_index_ = index;
 226   }
 227
 228   // Return whether this symbol already has an index in the output
 229   // file symbol table.
 230   bool
 231   has_symtab_index() const
 232   { return this->symtab_index_ != 0; }
 233
 234   // Return the index of this symbol in the dynamic symbol table.  A
 235   // value of -1U means that this symbol is not going into the dynamic
 236   // symbol table.  This starts out as zero, and is set to a non-zero
 237   // during Layout::finalize.  It is an error to ask for the dynamic
 238   // symbol table index before it has been set.
 239   unsigned int
 240   dynsym_index() const
 241   {
 242     gold_assert(this->dynsym_index_ != 0);
 243     return this->dynsym_index_;
 244   }
 245
 246   // Set the index of the symbol in the dynamic symbol table.
 247   void
 248   set_dynsym_index(unsigned int index)
 249   {
 250     gold_assert(index != 0);
 251     this->dynsym_index_ = index;
 252   }
 253
 254   // Return whether this symbol already has an index in the dynamic
 255   // symbol table.
 256   bool
 257   has_dynsym_index() const
 258   { return this->dynsym_index_ != 0; }
 259
 260   // Return whether this symbol has an entry in the GOT section.
 261   bool
 262   has_got_offset() const
 263   { return this->has_got_offset_; }
 264
 265   // Return the offset into the GOT section of this symbol.
 266   unsigned int
 267   got_offset() const
 268   {
 269     gold_assert(this->has_got_offset());
 270     return this->got_offset_;
 271   }
 272
 273   // Set the GOT offset of this symbol.
 274   void
 275   set_got_offset(unsigned int got_offset)
 276   {
 277     this->has_got_offset_ = true;
 278     this->got_offset_ = got_offset;
 279   }
 280
 281   // Return whether this symbol has an entry in the PLT section.
 282   bool
 283   has_plt_offset() const
 284   { return this->has_plt_offset_; }
 285
 286   // Return the offset into the PLT section of this symbol.
 287   unsigned int
 288   plt_offset() const
 289   {
 290     gold_assert(this->has_plt_offset());
 291     return this->plt_offset_;
 292   }
 293
 294   // Set the PLT offset of this symbol.
 295   void
 296   set_plt_offset(unsigned int plt_offset)
 297   {
 298     this->has_plt_offset_ = true;
 299     this->plt_offset_ = plt_offset;
 300   }
 301
 302   // Return true if the final value of this symbol is known at link
 303   // time.
 304   bool
 305   final_value_is_known(const General_options* options) const
 306   {
 307     if (options->is_shared())
 308       return false;
 309     return this->source_ != FROM_OBJECT || !this->object()->is_dynamic();
 310   }
 311
 312   // Return whether this is a defined symbol (not undefined or
 313   // common).
 314   bool
 315   is_defined() const
 316   {
 317     return (this->source_ != FROM_OBJECT
 318             || (this->shndx() != elfcpp::SHN_UNDEF
 319                 && this->shndx() != elfcpp::SHN_COMMON));
 320   }
 321
 322   // Return true if this symbol is from a dynamic object.
 323   bool
 324   is_from_dynobj() const
 325   {
 326     return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
 327   }
 328
 329   // Return whether this is an undefined symbol.
 330   bool
 331   is_undefined() const
 332   {
 333     return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF;
 334   }
 335
 336   // Return whether this is a common symbol.
 337   bool
 338   is_common() const
 339   {
 340     return (this->source_ == FROM_OBJECT
 341             && (this->shndx() == elfcpp::SHN_COMMON
 342                 || this->type_ == elfcpp::STT_COMMON));
 343   }
 344
 345   // Return whether this symbol can be seen outside this object.
 346   bool
 347   is_externally_visible() const
 348   {
 349     return (this->visibility_ == elfcpp::STV_DEFAULT
 350             || this->visibility_ == elfcpp::STV_PROTECTED);
 351   }
 352
 353   // Return whether there should be a warning for references to this
 354   // symbol.
 355   bool
 356   has_warning() const
 357   { return this->has_warning_; }
 358
 359   // Mark this symbol as having a warning.
 360   void
 361   set_has_warning()
 362   { this->has_warning_ = true; }
 363
 364  protected:
 365   // Instances of this class should always be created at a specific
 366   // size.
 367   Symbol()
 368   { memset(this, 0, sizeof *this); }
 369
 370   // Initialize the general fields.
 371   void
 372   init_fields(const char* name, const char* version,
 373               elfcpp::STT type, elfcpp::STB binding,
 374               elfcpp::STV visibility, unsigned char nonvis);
 375
 376   // Initialize fields from an ELF symbol in OBJECT.
 377   template<int size, bool big_endian>
 378   void
 379   init_base(const char *name, const char* version, Object* object,
 380             const elfcpp::Sym<size, big_endian>&);
 381
 382   // Initialize fields for an Output_data.
 383   void
 384   init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
 385             elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
 386
 387   // Initialize fields for an Output_segment.
 388   void
 389   init_base(const char* name, Output_segment* os, elfcpp::STT type,
 390             elfcpp::STB binding, elfcpp::STV visibility,
 391             unsigned char nonvis, Segment_offset_base offset_base);
 392
 393   // Initialize fields for a constant.
 394   void
 395   init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
 396             elfcpp::STV visibility, unsigned char nonvis);
 397
 398   // Override existing symbol.
 399   template<int size, bool big_endian>
 400   void
 401   override_base(const elfcpp::Sym<size, big_endian>&, Object* object,
 402                 const char* version);
 403
 404  private:
 405   Symbol(const Symbol&);
 406   Symbol& operator=(const Symbol&);
 407
 408   // Symbol name (expected to point into a Stringpool).
 409   const char* name_;
 410   // Symbol version (expected to point into a Stringpool).  This may
 411   // be NULL.
 412   const char* version_;
 413
 414   union
 415   {
 416     // This struct is used if SOURCE_ == FROM_OBJECT.
 417     struct
 418     {
 419       // Object in which symbol is defined, or in which it was first
 420       // seen.
 421       Object* object;
 422       // Section number in object_ in which symbol is defined.
 423       unsigned int shndx;
 424     } from_object;
 425
 426     // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
 427     struct
 428     {
 429       // Output_data in which symbol is defined.  Before
 430       // Layout::finalize the symbol's value is an offset within the
 431       // Output_data.
 432       Output_data* output_data;
 433       // True if the offset is from the end, false if the offset is
 434       // from the beginning.
 435       bool offset_is_from_end;
 436     } in_output_data;
 437
 438     // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
 439     struct
 440     {
 441       // Output_segment in which the symbol is defined.  Before
 442       // Layout::finalize the symbol's value is an offset.
 443       Output_segment* output_segment;
 444       // The base to use for the offset before Layout::finalize.
 445       Segment_offset_base offset_base;
 446     } in_output_segment;
 447   } u_;
 448
 449   // The index of this symbol in the output file.  If the symbol is
 450   // not going into the output file, this value is -1U.  This field
 451   // starts as always holding zero.  It is set to a non-zero value by
 452   // Symbol_table::finalize.
 453   unsigned int symtab_index_;
 454
 455   // The index of this symbol in the dynamic symbol table.  If the
 456   // symbol is not going into the dynamic symbol table, this value is
 457   // -1U.  This field starts as always holding zero.  It is set to a
 458   // non-zero value during Layout::finalize.
 459   unsigned int dynsym_index_;
 460
 461   // If this symbol has an entry in the GOT section (has_got_offset_
 462   // is true), this is the offset from the start of the GOT section.
 463   unsigned int got_offset_;
 464
 465   // If this symbol has an entry in the PLT section (has_plt_offset_
 466   // is true), then this is the offset from the start of the PLT
 467   // section.
 468   unsigned int plt_offset_;
 469
 470   // Symbol type.
 471   elfcpp::STT type_ : 4;
 472   // Symbol binding.
 473   elfcpp::STB binding_ : 4;
 474   // Symbol visibility.
 475   elfcpp::STV visibility_ : 2;
 476   // Rest of symbol st_other field.
 477   unsigned int nonvis_ : 6;
 478   // The type of symbol.
 479   Source source_ : 3;
 480   // True if this symbol always requires special target-specific
 481   // handling.
 482   bool is_target_special_ : 1;
 483   // True if this is the default version of the symbol.
 484   bool is_def_ : 1;
 485   // True if this symbol really forwards to another symbol.  This is
 486   // used when we discover after the fact that two different entries
 487   // in the hash table really refer to the same symbol.  This will
 488   // never be set for a symbol found in the hash table, but may be set
 489   // for a symbol found in the list of symbols attached to an Object.
 490   // It forwards to the symbol found in the forwarders_ map of
 491   // Symbol_table.
 492   bool is_forwarder_ : 1;
 493   // True if this symbol needs to be in the dynamic symbol table.
 494   bool needs_dynsym_entry_ : 1;
 495   // True if we've seen this symbol in a regular object.
 496   bool in_reg_ : 1;
 497   // True if we've seen this symbol in a dynamic object.
 498   bool in_dyn_ : 1;
 499   // True if the symbol has an entry in the GOT section.
 500   bool has_got_offset_ : 1;
 501   // True if the symbol has an entry in the PLT section.
 502   bool has_plt_offset_ : 1;
 503   // True if there is a warning for this symbol.
 504   bool has_warning_ : 1;
 505 };
 506
 507 // The parts of a symbol which are size specific.  Using a template
 508 // derived class like this helps us use less space on a 32-bit system.
 509
 510 template<int size>
 511 class Sized_symbol : public Symbol
 512 {
 513  public:
 514   typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
 515   typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
 516
 517   Sized_symbol()
 518   { }
 519
 520   // Initialize fields from an ELF symbol in OBJECT.
 521   template<bool big_endian>
 522   void
 523   init(const char *name, const char* version, Object* object,
 524        const elfcpp::Sym<size, big_endian>&);
 525
 526   // Initialize fields for an Output_data.
 527   void
 528   init(const char* name, Output_data*, Value_type value, Size_type symsize,
 529        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 530        bool offset_is_from_end);
 531
 532   // Initialize fields for an Output_segment.
 533   void
 534   init(const char* name, Output_segment*, Value_type value, Size_type symsize,
 535        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 536        Segment_offset_base offset_base);
 537
 538   // Initialize fields for a constant.
 539   void
 540   init(const char* name, Value_type value, Size_type symsize,
 541        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
 542
 543   // Override existing symbol.
 544   template<bool big_endian>
 545   void
 546   override(const elfcpp::Sym<size, big_endian>&, Object* object,
 547            const char* version);
 548
 549   // Return the symbol's value.
 550   Value_type
 551   value() const
 552   { return this->value_; }
 553
 554   // Return the symbol's size (we can't call this 'size' because that
 555   // is a template parameter).
 556   Size_type
 557   symsize() const
 558   { return this->symsize_; }
 559
 560   // Set the symbol size.  This is used when resolving common symbols.
 561   void
 562   set_symsize(Size_type symsize)
 563   { this->symsize_ = symsize; }
 564
 565   // Set the symbol value.  This is called when we store the final
 566   // values of the symbols into the symbol table.
 567   void
 568   set_value(Value_type value)
 569   { this->value_ = value; }
 570
 571  private:
 572   Sized_symbol(const Sized_symbol&);
 573   Sized_symbol& operator=(const Sized_symbol&);
 574
 575   // Symbol value.  Before Layout::finalize this is the offset in the
 576   // input section.  This is set to the final value during
 577   // Layout::finalize.
 578   Value_type value_;
 579   // Symbol size.
 580   Size_type symsize_;
 581 };
 582
 583 // A struct describing a symbol defined by the linker, where the value
 584 // of the symbol is defined based on an output section.  This is used
 585 // for symbols defined by the linker, like "_init_array_start".
 586
 587 struct Define_symbol_in_section
 588 {
 589   // The symbol name.
 590   const char* name;
 591   // The name of the output section with which this symbol should be
 592   // associated.  If there is no output section with that name, the
 593   // symbol will be defined as zero.
 594   const char* output_section;
 595   // The offset of the symbol within the output section.  This is an
 596   // offset from the start of the output section, unless start_at_end
 597   // is true, in which case this is an offset from the end of the
 598   // output section.
 599   uint64_t value;
 600   // The size of the symbol.
 601   uint64_t size;
 602   // The symbol type.
 603   elfcpp::STT type;
 604   // The symbol binding.
 605   elfcpp::STB binding;
 606   // The symbol visibility.
 607   elfcpp::STV visibility;
 608   // The rest of the st_other field.
 609   unsigned char nonvis;
 610   // If true, the value field is an offset from the end of the output
 611   // section.
 612   bool offset_is_from_end;
 613   // If true, this symbol is defined only if we see a reference to it.
 614   bool only_if_ref;
 615 };
 616
 617 // A struct describing a symbol defined by the linker, where the value
 618 // of the symbol is defined based on a segment.  This is used for
 619 // symbols defined by the linker, like "_end".  We describe the
 620 // segment with which the symbol should be associated by its
 621 // characteristics.  If no segment meets these characteristics, the
 622 // symbol will be defined as zero.  If there is more than one segment
 623 // which meets these characteristics, we will use the first one.
 624
 625 struct Define_symbol_in_segment
 626 {
 627   // The symbol name.
 628   const char* name;
 629   // The segment type where the symbol should be defined, typically
 630   // PT_LOAD.
 631   elfcpp::PT segment_type;
 632   // Bitmask of segment flags which must be set.
 633   elfcpp::PF segment_flags_set;
 634   // Bitmask of segment flags which must be clear.
 635   elfcpp::PF segment_flags_clear;
 636   // The offset of the symbol within the segment.  The offset is
 637   // calculated from the position set by offset_base.
 638   uint64_t value;
 639   // The size of the symbol.
 640   uint64_t size;
 641   // The symbol type.
 642   elfcpp::STT type;
 643   // The symbol binding.
 644   elfcpp::STB binding;
 645   // The symbol visibility.
 646   elfcpp::STV visibility;
 647   // The rest of the st_other field.
 648   unsigned char nonvis;
 649   // The base from which we compute the offset.
 650   Symbol::Segment_offset_base offset_base;
 651   // If true, this symbol is defined only if we see a reference to it.
 652   bool only_if_ref;
 653 };
 654
 655 // This class manages warnings.  Warnings are a GNU extension.  When
 656 // we see a section named .gnu.warning.SYM in an object file, and if
 657 // we wind using the definition of SYM from that object file, then we
 658 // will issue a warning for any relocation against SYM from a
 659 // different object file.  The text of the warning is the contents of
 660 // the section.  This is not precisely the definition used by the old
 661 // GNU linker; the old GNU linker treated an occurrence of
 662 // .gnu.warning.SYM as defining a warning symbol.  A warning symbol
 663 // would trigger a warning on any reference.  However, it was
 664 // inconsistent in that a warning in a dynamic object only triggered
 665 // if there was no definition in a regular object.  This linker is
 666 // different in that we only issue a warning if we use the symbol
 667 // definition from the same object file as the warning section.
 668
 669 class Warnings
 670 {
 671  public:
 672   Warnings()
 673     : warnings_()
 674   { }
 675
 676   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 677   void
 678   add_warning(Symbol_table* symtab, const char* name, Object* obj,
 679               unsigned int shndx);
 680
 681   // For each symbol for which we should give a warning, make a note
 682   // on the symbol.
 683   void
 684   note_warnings(Symbol_table* symtab);
 685
 686   // Issue a warning for a reference to SYM at LOCATION.
 687   void
 688   issue_warning(const Symbol* sym, const std::string& location) const;
 689
 690  private:
 691   Warnings(const Warnings&);
 692   Warnings& operator=(const Warnings&);
 693
 694   // What we need to know to get the warning text.
 695   struct Warning_location
 696   {
 697     // The object the warning is in.
 698     Object* object;
 699     // The index of the warning section.
 700     unsigned int shndx;
 701     // The warning text if we have already loaded it.
 702     std::string text;
 703
 704     Warning_location()
 705       : object(NULL), shndx(0), text()
 706     { }
 707
 708     void
 709     set(Object* o, unsigned int s)
 710     {
 711       this->object = o;
 712       this->shndx = s;
 713     }
 714
 715     void
 716     set_text(const char* t, off_t l)
 717     { this->text.assign(t, l); }
 718   };
 719
 720   // A mapping from warning symbol names (canonicalized in
 721   // Symbol_table's namepool_ field) to
 722   typedef Unordered_map<const char*, Warning_location> Warning_table;
 723
 724   Warning_table warnings_;
 725 };
 726
 727 // The main linker symbol table.
 728
 729 class Symbol_table
 730 {
 731  public:
 732   Symbol_table();
 733
 734   ~Symbol_table();
 735
 736   // Add COUNT external symbols from the relocatable object RELOBJ to
 737   // the symbol table.  SYMS is the symbols, SYM_NAMES is their names,
 738   // SYM_NAME_SIZE is the size of SYM_NAMES.  This sets SYMPOINTERS to
 739   // point to the symbols in the symbol table.
 740   template<int size, bool big_endian>
 741   void
 742   add_from_relobj(Sized_relobj<size, big_endian>* relobj,
 743                   const unsigned char* syms, size_t count,
 744                   const char* sym_names, size_t sym_name_size,
 745                   Symbol** sympointers);
 746
 747   // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
 748   // symbol table.  SYMS is the symbols.  SYM_NAMES is their names.
 749   // SYM_NAME_SIZE is the size of SYM_NAMES.  The other parameters are
 750   // symbol version data.
 751   template<int size, bool big_endian>
 752   void
 753   add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
 754                   const unsigned char* syms, size_t count,
 755                   const char* sym_names, size_t sym_name_size,
 756                   const unsigned char* versym, size_t versym_size,
 757                   const std::vector<const char*>*);
 758
 759   // Define a special symbol based on an Output_data.  It is a
 760   // multiple definition error if this symbol is already defined.
 761   Symbol*
 762   define_in_output_data(const Target*, const char* name, const char* version,
 763                         Output_data*, uint64_t value, uint64_t symsize,
 764                         elfcpp::STT type, elfcpp::STB binding,
 765                         elfcpp::STV visibility, unsigned char nonvis,
 766                         bool offset_is_from_end, bool only_if_ref);
 767
 768   // Define a special symbol based on an Output_segment.  It is a
 769   // multiple definition error if this symbol is already defined.
 770   Symbol*
 771   define_in_output_segment(const Target*, const char* name,
 772                            const char* version, Output_segment*,
 773                            uint64_t value, uint64_t symsize,
 774                            elfcpp::STT type, elfcpp::STB binding,
 775                            elfcpp::STV visibility, unsigned char nonvis,
 776                            Symbol::Segment_offset_base, bool only_if_ref);
 777
 778   // Define a special symbol with a constant value.  It is a multiple
 779   // definition error if this symbol is already defined.
 780   Symbol*
 781   define_as_constant(const Target*, const char* name, const char* version,
 782                      uint64_t value, uint64_t symsize, elfcpp::STT type,
 783                      elfcpp::STB binding, elfcpp::STV visibility,
 784                      unsigned char nonvis, bool only_if_ref);
 785
 786   // Define a set of symbols in output sections.
 787   void
 788   define_symbols(const Layout*, const Target*, int count,
 789                  const Define_symbol_in_section*);
 790
 791   // Define a set of symbols in output segments.
 792   void
 793   define_symbols(const Layout*, const Target*, int count,
 794                  const Define_symbol_in_segment*);
 795
 796   // Look up a symbol.
 797   Symbol*
 798   lookup(const char*, const char* version = NULL) const;
 799
 800   // Return the real symbol associated with the forwarder symbol FROM.
 801   Symbol*
 802   resolve_forwards(const Symbol* from) const;
 803
 804   // Return the bitsize (32 or 64) of the symbols in the table.
 805   int
 806   get_size() const
 807   { return this->size_; }
 808
 809   // Return the sized version of a symbol in this table.
 810   template<int size>
 811   Sized_symbol<size>*
 812   get_sized_symbol(Symbol* ACCEPT_SIZE) const;
 813
 814   template<int size>
 815   const Sized_symbol<size>*
 816   get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
 817
 818   // Return the count of undefined symbols seen.
 819   int
 820   saw_undefined() const
 821   { return this->saw_undefined_; }
 822
 823   // Allocate the common symbols
 824   void
 825   allocate_commons(const General_options&, Layout*);
 826
 827   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 828   void
 829   add_warning(const char* name, Object* obj, unsigned int shndx)
 830   { this->warnings_.add_warning(this, name, obj, shndx); }
 831
 832   // Canonicalize a symbol name for use in the hash table.
 833   const char*
 834   canonicalize_name(const char* name)
 835   { return this->namepool_.add(name, NULL); }
 836
 837   // Possibly issue a warning for a reference to SYM at LOCATION which
 838   // is in OBJ.
 839   void
 840   issue_warning(const Symbol* sym, const std::string& location) const
 841   { this->warnings_.issue_warning(sym, location); }
 842
 843   // Set the dynamic symbol indexes.  INDEX is the index of the first
 844   // global dynamic symbol.  Pointers to the symbols are stored into
 845   // the vector.  The names are stored into the Stringpool.  This
 846   // returns an updated dynamic symbol index.
 847   unsigned int
 848   set_dynsym_indexes(const General_options*, const Target*, unsigned int index,
 849                      std::vector<Symbol*>*, Stringpool*, Versions*);
 850
 851   // Finalize the symbol table after we have set the final addresses
 852   // of all the input sections.  This sets the final symbol indexes,
 853   // values and adds the names to *POOL.  INDEX is the index of the
 854   // first global symbol.  OFF is the file offset of the global symbol
 855   // table, DYNOFF is the offset of the globals in the dynamic symbol
 856   // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
 857   // symbol, and DYNCOUNT is the number of global dynamic symbols.
 858   // This records the parameters, and returns the new file offset.
 859   off_t
 860   finalize(unsigned int index, off_t off, off_t dynoff,
 861            size_t dyn_global_index, size_t dyncount, Stringpool* pool);
 862
 863   // Write out the global symbols.
 864   void
 865   write_globals(const Target*, const Stringpool*, const Stringpool*,
 866                 Output_file*) const;
 867
 868   // Write out a section symbol.  Return the updated offset.
 869   void
 870   write_section_symbol(const Target*, const Output_section*, Output_file*,
 871                        off_t) const;
 872
 873  private:
 874   Symbol_table(const Symbol_table&);
 875   Symbol_table& operator=(const Symbol_table&);
 876
 877   // Set the size (32 or 64) of the symbols in the table.
 878   void
 879   set_size(int size)
 880   { this->size_ = size; }
 881
 882   // Make FROM a forwarder symbol to TO.
 883   void
 884   make_forwarder(Symbol* from, Symbol* to);
 885
 886   // Add a symbol.
 887   template<int size, bool big_endian>
 888   Symbol*
 889   add_from_object(Object*, const char *name, Stringpool::Key name_key,
 890                   const char *version, Stringpool::Key version_key,
 891                   bool def, const elfcpp::Sym<size, big_endian>& sym);
 892
 893   // Resolve symbols.
 894   template<int size, bool big_endian>
 895   static void
 896   resolve(Sized_symbol<size>* to,
 897           const elfcpp::Sym<size, big_endian>& sym,
 898           Object*, const char* version);
 899
 900   template<int size, bool big_endian>
 901   static void
 902   resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
 903           const char* version ACCEPT_SIZE_ENDIAN);
 904
 905   // Define a special symbol.
 906   template<int size, bool big_endian>
 907   Sized_symbol<size>*
 908   define_special_symbol(const Target* target, const char* name,
 909                         const char* version, bool only_if_ref
 910                         ACCEPT_SIZE_ENDIAN);
 911
 912   // Define a symbol in an Output_data, sized version.
 913   template<int size>
 914   Sized_symbol<size>*
 915   do_define_in_output_data(const Target*, const char* name,
 916                            const char* version, Output_data*,
 917                            typename elfcpp::Elf_types<size>::Elf_Addr value,
 918                            typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 919                            elfcpp::STT type, elfcpp::STB binding,
 920                            elfcpp::STV visibility, unsigned char nonvis,
 921                            bool offset_is_from_end, bool only_if_ref);
 922
 923   // Define a symbol in an Output_segment, sized version.
 924   template<int size>
 925   Sized_symbol<size>*
 926   do_define_in_output_segment(
 927     const Target*, const char* name, const char* version, Output_segment* os,
 928     typename elfcpp::Elf_types<size>::Elf_Addr value,
 929     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 930     elfcpp::STT type, elfcpp::STB binding,
 931     elfcpp::STV visibility, unsigned char nonvis,
 932     Symbol::Segment_offset_base offset_base, bool only_if_ref);
 933
 934   // Define a symbol as a constant, sized version.
 935   template<int size>
 936   Sized_symbol<size>*
 937   do_define_as_constant(
 938     const Target*, const char* name, const char* version,
 939     typename elfcpp::Elf_types<size>::Elf_Addr value,
 940     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 941     elfcpp::STT type, elfcpp::STB binding,
 942     elfcpp::STV visibility, unsigned char nonvis,
 943     bool only_if_ref);
 944
 945   // Allocate the common symbols, sized version.
 946   template<int size>
 947   void
 948   do_allocate_commons(const General_options&, Layout*);
 949
 950   // Finalize symbols specialized for size.
 951   template<int size>
 952   off_t
 953   sized_finalize(unsigned int, off_t, Stringpool*);
 954
 955   // Write globals specialized for size and endianness.
 956   template<int size, bool big_endian>
 957   void
 958   sized_write_globals(const Target*, const Stringpool*, const Stringpool*,
 959                       Output_file*) const;
 960
 961   // Write out a symbol to P.
 962   template<int size, bool big_endian>
 963   void
 964   sized_write_symbol(Sized_symbol<size>*, unsigned int shndx,
 965                      const Stringpool*, unsigned char* p
 966                      ACCEPT_SIZE_ENDIAN) const;
 967
 968   // Write out a section symbol, specialized for size and endianness.
 969   template<int size, bool big_endian>
 970   void
 971   sized_write_section_symbol(const Output_section*, Output_file*, off_t) const;
 972
 973   // The type of the symbol hash table.
 974
 975   typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
 976
 977   struct Symbol_table_hash
 978   {
 979     size_t
 980     operator()(const Symbol_table_key&) const;
 981   };
 982
 983   struct Symbol_table_eq
 984   {
 985     bool
 986     operator()(const Symbol_table_key&, const Symbol_table_key&) const;
 987   };
 988
 989   typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
 990                         Symbol_table_eq> Symbol_table_type;
 991
 992   // The type of the list of common symbols.
 993
 994   typedef std::vector<Symbol*> Commons_type;
 995
 996   // The size of the symbols in the symbol table (32 or 64).
 997   int size_;
 998
 999   // We increment this every time we see a new undefined symbol, for
1000   // use in archive groups.
1001   int saw_undefined_;
1002
1003   // The index of the first global symbol in the output file.
1004   unsigned int first_global_index_;
1005
1006   // The file offset within the output symtab section where we should
1007   // write the table.
1008   off_t offset_;
1009
1010   // The number of global symbols we want to write out.
1011   size_t output_count_;
1012
1013   // The file offset of the global dynamic symbols, or 0 if none.
1014   off_t dynamic_offset_;
1015
1016   // The index of the first global dynamic symbol.
1017   unsigned int first_dynamic_global_index_;
1018
1019   // The number of global dynamic symbols, or 0 if none.
1020   off_t dynamic_count_;
1021
1022   // The symbol hash table.
1023   Symbol_table_type table_;
1024
1025   // A pool of symbol names.  This is used for all global symbols.
1026   // Entries in the hash table point into this pool.
1027   Stringpool namepool_;
1028
1029   // Forwarding symbols.
1030   Unordered_map<const Symbol*, Symbol*> forwarders_;
1031
1032   // We don't expect there to be very many common symbols, so we keep
1033   // a list of them.  When we find a common symbol we add it to this
1034   // list.  It is possible that by the time we process the list the
1035   // symbol is no longer a common symbol.  It may also have become a
1036   // forwarder.
1037   Commons_type commons_;
1038
1039   // Manage symbol warnings.
1040   Warnings warnings_;
1041 };
1042
1043 // We inline get_sized_symbol for efficiency.
1044
1045 template<int size>
1046 Sized_symbol<size>*
1047 Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const
1048 {
1049   gold_assert(size == this->get_size());
1050   return static_cast<Sized_symbol<size>*>(sym);
1051 }
1052
1053 template<int size>
1054 const Sized_symbol<size>*
1055 Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const
1056 {
1057   gold_assert(size == this->get_size());
1058   return static_cast<const Sized_symbol<size>*>(sym);
1059 }
1060
1061 } // End namespace gold.
1062
1063 #endif // !defined(GOLD_SYMTAB_H)