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   {
 182     return (this->needs_dynsym_entry_
 183             || (this->in_reg() && this->in_dyn()));
 184   }
 185
 186   // Mark this symbol as needing an entry in the dynamic symbol table.
 187   void
 188   set_needs_dynsym_entry()
 189   { this->needs_dynsym_entry_ = true; }
 190
 191   // Return whether this symbol has been seen in a regular object.
 192   bool
 193   in_reg() const
 194   { return this->in_reg_; }
 195
 196   // Mark this symbol as having been seen in a regular object.
 197   void
 198   set_in_reg()
 199   { this->in_reg_ = true; }
 200
 201   // Return whether this symbol has been seen in a dynamic object.
 202   bool
 203   in_dyn() const
 204   { return this->in_dyn_; }
 205
 206   // Mark this symbol as having been seen in a dynamic object.
 207   void
 208   set_in_dyn()
 209   { this->in_dyn_ = true; }
 210
 211   // Return the index of this symbol in the output file symbol table.
 212   // A value of -1U means that this symbol is not going into the
 213   // output file.  This starts out as zero, and is set to a non-zero
 214   // value by Symbol_table::finalize.  It is an error to ask for the
 215   // symbol table index before it has been set.
 216   unsigned int
 217   symtab_index() const
 218   {
 219     gold_assert(this->symtab_index_ != 0);
 220     return this->symtab_index_;
 221   }
 222
 223   // Set the index of the symbol in the output file symbol table.
 224   void
 225   set_symtab_index(unsigned int index)
 226   {
 227     gold_assert(index != 0);
 228     this->symtab_index_ = index;
 229   }
 230
 231   // Return whether this symbol already has an index in the output
 232   // file symbol table.
 233   bool
 234   has_symtab_index() const
 235   { return this->symtab_index_ != 0; }
 236
 237   // Return the index of this symbol in the dynamic symbol table.  A
 238   // value of -1U means that this symbol is not going into the dynamic
 239   // symbol table.  This starts out as zero, and is set to a non-zero
 240   // during Layout::finalize.  It is an error to ask for the dynamic
 241   // symbol table index before it has been set.
 242   unsigned int
 243   dynsym_index() const
 244   {
 245     gold_assert(this->dynsym_index_ != 0);
 246     return this->dynsym_index_;
 247   }
 248
 249   // Set the index of the symbol in the dynamic symbol table.
 250   void
 251   set_dynsym_index(unsigned int index)
 252   {
 253     gold_assert(index != 0);
 254     this->dynsym_index_ = index;
 255   }
 256
 257   // Return whether this symbol already has an index in the dynamic
 258   // symbol table.
 259   bool
 260   has_dynsym_index() const
 261   { return this->dynsym_index_ != 0; }
 262
 263   // Return whether this symbol has an entry in the GOT section.
 264   bool
 265   has_got_offset() const
 266   { return this->has_got_offset_; }
 267
 268   // Return the offset into the GOT section of this symbol.
 269   unsigned int
 270   got_offset() const
 271   {
 272     gold_assert(this->has_got_offset());
 273     return this->got_offset_;
 274   }
 275
 276   // Set the GOT offset of this symbol.
 277   void
 278   set_got_offset(unsigned int got_offset)
 279   {
 280     this->has_got_offset_ = true;
 281     this->got_offset_ = got_offset;
 282   }
 283
 284   // Return whether this symbol has an entry in the PLT section.
 285   bool
 286   has_plt_offset() const
 287   { return this->has_plt_offset_; }
 288
 289   // Return the offset into the PLT section of this symbol.
 290   unsigned int
 291   plt_offset() const
 292   {
 293     gold_assert(this->has_plt_offset());
 294     return this->plt_offset_;
 295   }
 296
 297   // Set the PLT offset of this symbol.
 298   void
 299   set_plt_offset(unsigned int plt_offset)
 300   {
 301     this->has_plt_offset_ = true;
 302     this->plt_offset_ = plt_offset;
 303   }
 304
 305   // Return true if the final value of this symbol is known at link
 306   // time.
 307   bool
 308   final_value_is_known(const General_options* options) const
 309   {
 310     if (options->is_shared())
 311       return false;
 312     return this->source_ != FROM_OBJECT || !this->object()->is_dynamic();
 313   }
 314
 315   // Return whether this is a defined symbol (not undefined or
 316   // common).
 317   bool
 318   is_defined() const
 319   {
 320     return (this->source_ != FROM_OBJECT
 321             || (this->shndx() != elfcpp::SHN_UNDEF
 322                 && this->shndx() != elfcpp::SHN_COMMON));
 323   }
 324
 325   // Return true if this symbol is from a dynamic object.
 326   bool
 327   is_from_dynobj() const
 328   {
 329     return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
 330   }
 331
 332   // Return whether this is an undefined symbol.
 333   bool
 334   is_undefined() const
 335   {
 336     return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF;
 337   }
 338
 339   // Return whether this is a common symbol.
 340   bool
 341   is_common() const
 342   {
 343     return (this->source_ == FROM_OBJECT
 344             && (this->shndx() == elfcpp::SHN_COMMON
 345                 || this->type_ == elfcpp::STT_COMMON));
 346   }
 347
 348   // Return whether this symbol can be seen outside this object.
 349   bool
 350   is_externally_visible() const
 351   {
 352     return (this->visibility_ == elfcpp::STV_DEFAULT
 353             || this->visibility_ == elfcpp::STV_PROTECTED);
 354   }
 355
 356   // Return whether there should be a warning for references to this
 357   // symbol.
 358   bool
 359   has_warning() const
 360   { return this->has_warning_; }
 361
 362   // Mark this symbol as having a warning.
 363   void
 364   set_has_warning()
 365   { this->has_warning_ = true; }
 366
 367  protected:
 368   // Instances of this class should always be created at a specific
 369   // size.
 370   Symbol()
 371   { memset(this, 0, sizeof *this); }
 372
 373   // Initialize the general fields.
 374   void
 375   init_fields(const char* name, const char* version,
 376               elfcpp::STT type, elfcpp::STB binding,
 377               elfcpp::STV visibility, unsigned char nonvis);
 378
 379   // Initialize fields from an ELF symbol in OBJECT.
 380   template<int size, bool big_endian>
 381   void
 382   init_base(const char *name, const char* version, Object* object,
 383             const elfcpp::Sym<size, big_endian>&);
 384
 385   // Initialize fields for an Output_data.
 386   void
 387   init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
 388             elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
 389
 390   // Initialize fields for an Output_segment.
 391   void
 392   init_base(const char* name, Output_segment* os, elfcpp::STT type,
 393             elfcpp::STB binding, elfcpp::STV visibility,
 394             unsigned char nonvis, Segment_offset_base offset_base);
 395
 396   // Initialize fields for a constant.
 397   void
 398   init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
 399             elfcpp::STV visibility, unsigned char nonvis);
 400
 401   // Override existing symbol.
 402   template<int size, bool big_endian>
 403   void
 404   override_base(const elfcpp::Sym<size, big_endian>&, Object* object,
 405                 const char* version);
 406
 407  private:
 408   Symbol(const Symbol&);
 409   Symbol& operator=(const Symbol&);
 410
 411   // Symbol name (expected to point into a Stringpool).
 412   const char* name_;
 413   // Symbol version (expected to point into a Stringpool).  This may
 414   // be NULL.
 415   const char* version_;
 416
 417   union
 418   {
 419     // This struct is used if SOURCE_ == FROM_OBJECT.
 420     struct
 421     {
 422       // Object in which symbol is defined, or in which it was first
 423       // seen.
 424       Object* object;
 425       // Section number in object_ in which symbol is defined.
 426       unsigned int shndx;
 427     } from_object;
 428
 429     // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
 430     struct
 431     {
 432       // Output_data in which symbol is defined.  Before
 433       // Layout::finalize the symbol's value is an offset within the
 434       // Output_data.
 435       Output_data* output_data;
 436       // True if the offset is from the end, false if the offset is
 437       // from the beginning.
 438       bool offset_is_from_end;
 439     } in_output_data;
 440
 441     // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
 442     struct
 443     {
 444       // Output_segment in which the symbol is defined.  Before
 445       // Layout::finalize the symbol's value is an offset.
 446       Output_segment* output_segment;
 447       // The base to use for the offset before Layout::finalize.
 448       Segment_offset_base offset_base;
 449     } in_output_segment;
 450   } u_;
 451
 452   // The index of this symbol in the output file.  If the symbol is
 453   // not going into the output file, this value is -1U.  This field
 454   // starts as always holding zero.  It is set to a non-zero value by
 455   // Symbol_table::finalize.
 456   unsigned int symtab_index_;
 457
 458   // The index of this symbol in the dynamic symbol table.  If the
 459   // symbol is not going into the dynamic symbol table, this value is
 460   // -1U.  This field starts as always holding zero.  It is set to a
 461   // non-zero value during Layout::finalize.
 462   unsigned int dynsym_index_;
 463
 464   // If this symbol has an entry in the GOT section (has_got_offset_
 465   // is true), this is the offset from the start of the GOT section.
 466   unsigned int got_offset_;
 467
 468   // If this symbol has an entry in the PLT section (has_plt_offset_
 469   // is true), then this is the offset from the start of the PLT
 470   // section.
 471   unsigned int plt_offset_;
 472
 473   // Symbol type.
 474   elfcpp::STT type_ : 4;
 475   // Symbol binding.
 476   elfcpp::STB binding_ : 4;
 477   // Symbol visibility.
 478   elfcpp::STV visibility_ : 2;
 479   // Rest of symbol st_other field.
 480   unsigned int nonvis_ : 6;
 481   // The type of symbol.
 482   Source source_ : 3;
 483   // True if this symbol always requires special target-specific
 484   // handling.
 485   bool is_target_special_ : 1;
 486   // True if this is the default version of the symbol.
 487   bool is_def_ : 1;
 488   // True if this symbol really forwards to another symbol.  This is
 489   // used when we discover after the fact that two different entries
 490   // in the hash table really refer to the same symbol.  This will
 491   // never be set for a symbol found in the hash table, but may be set
 492   // for a symbol found in the list of symbols attached to an Object.
 493   // It forwards to the symbol found in the forwarders_ map of
 494   // Symbol_table.
 495   bool is_forwarder_ : 1;
 496   // True if this symbol needs to be in the dynamic symbol table.
 497   bool needs_dynsym_entry_ : 1;
 498   // True if we've seen this symbol in a regular object.
 499   bool in_reg_ : 1;
 500   // True if we've seen this symbol in a dynamic object.
 501   bool in_dyn_ : 1;
 502   // True if the symbol has an entry in the GOT section.
 503   bool has_got_offset_ : 1;
 504   // True if the symbol has an entry in the PLT section.
 505   bool has_plt_offset_ : 1;
 506   // True if there is a warning for this symbol.
 507   bool has_warning_ : 1;
 508 };
 509
 510 // The parts of a symbol which are size specific.  Using a template
 511 // derived class like this helps us use less space on a 32-bit system.
 512
 513 template<int size>
 514 class Sized_symbol : public Symbol
 515 {
 516  public:
 517   typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
 518   typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
 519
 520   Sized_symbol()
 521   { }
 522
 523   // Initialize fields from an ELF symbol in OBJECT.
 524   template<bool big_endian>
 525   void
 526   init(const char *name, const char* version, Object* object,
 527        const elfcpp::Sym<size, big_endian>&);
 528
 529   // Initialize fields for an Output_data.
 530   void
 531   init(const char* name, Output_data*, Value_type value, Size_type symsize,
 532        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 533        bool offset_is_from_end);
 534
 535   // Initialize fields for an Output_segment.
 536   void
 537   init(const char* name, Output_segment*, Value_type value, Size_type symsize,
 538        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
 539        Segment_offset_base offset_base);
 540
 541   // Initialize fields for a constant.
 542   void
 543   init(const char* name, Value_type value, Size_type symsize,
 544        elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
 545
 546   // Override existing symbol.
 547   template<bool big_endian>
 548   void
 549   override(const elfcpp::Sym<size, big_endian>&, Object* object,
 550            const char* version);
 551
 552   // Return the symbol's value.
 553   Value_type
 554   value() const
 555   { return this->value_; }
 556
 557   // Return the symbol's size (we can't call this 'size' because that
 558   // is a template parameter).
 559   Size_type
 560   symsize() const
 561   { return this->symsize_; }
 562
 563   // Set the symbol size.  This is used when resolving common symbols.
 564   void
 565   set_symsize(Size_type symsize)
 566   { this->symsize_ = symsize; }
 567
 568   // Set the symbol value.  This is called when we store the final
 569   // values of the symbols into the symbol table.
 570   void
 571   set_value(Value_type value)
 572   { this->value_ = value; }
 573
 574  private:
 575   Sized_symbol(const Sized_symbol&);
 576   Sized_symbol& operator=(const Sized_symbol&);
 577
 578   // Symbol value.  Before Layout::finalize this is the offset in the
 579   // input section.  This is set to the final value during
 580   // Layout::finalize.
 581   Value_type value_;
 582   // Symbol size.
 583   Size_type symsize_;
 584 };
 585
 586 // A struct describing a symbol defined by the linker, where the value
 587 // of the symbol is defined based on an output section.  This is used
 588 // for symbols defined by the linker, like "_init_array_start".
 589
 590 struct Define_symbol_in_section
 591 {
 592   // The symbol name.
 593   const char* name;
 594   // The name of the output section with which this symbol should be
 595   // associated.  If there is no output section with that name, the
 596   // symbol will be defined as zero.
 597   const char* output_section;
 598   // The offset of the symbol within the output section.  This is an
 599   // offset from the start of the output section, unless start_at_end
 600   // is true, in which case this is an offset from the end of the
 601   // output section.
 602   uint64_t value;
 603   // The size of the symbol.
 604   uint64_t size;
 605   // The symbol type.
 606   elfcpp::STT type;
 607   // The symbol binding.
 608   elfcpp::STB binding;
 609   // The symbol visibility.
 610   elfcpp::STV visibility;
 611   // The rest of the st_other field.
 612   unsigned char nonvis;
 613   // If true, the value field is an offset from the end of the output
 614   // section.
 615   bool offset_is_from_end;
 616   // If true, this symbol is defined only if we see a reference to it.
 617   bool only_if_ref;
 618 };
 619
 620 // A struct describing a symbol defined by the linker, where the value
 621 // of the symbol is defined based on a segment.  This is used for
 622 // symbols defined by the linker, like "_end".  We describe the
 623 // segment with which the symbol should be associated by its
 624 // characteristics.  If no segment meets these characteristics, the
 625 // symbol will be defined as zero.  If there is more than one segment
 626 // which meets these characteristics, we will use the first one.
 627
 628 struct Define_symbol_in_segment
 629 {
 630   // The symbol name.
 631   const char* name;
 632   // The segment type where the symbol should be defined, typically
 633   // PT_LOAD.
 634   elfcpp::PT segment_type;
 635   // Bitmask of segment flags which must be set.
 636   elfcpp::PF segment_flags_set;
 637   // Bitmask of segment flags which must be clear.
 638   elfcpp::PF segment_flags_clear;
 639   // The offset of the symbol within the segment.  The offset is
 640   // calculated from the position set by offset_base.
 641   uint64_t value;
 642   // The size of the symbol.
 643   uint64_t size;
 644   // The symbol type.
 645   elfcpp::STT type;
 646   // The symbol binding.
 647   elfcpp::STB binding;
 648   // The symbol visibility.
 649   elfcpp::STV visibility;
 650   // The rest of the st_other field.
 651   unsigned char nonvis;
 652   // The base from which we compute the offset.
 653   Symbol::Segment_offset_base offset_base;
 654   // If true, this symbol is defined only if we see a reference to it.
 655   bool only_if_ref;
 656 };
 657
 658 // This class manages warnings.  Warnings are a GNU extension.  When
 659 // we see a section named .gnu.warning.SYM in an object file, and if
 660 // we wind using the definition of SYM from that object file, then we
 661 // will issue a warning for any relocation against SYM from a
 662 // different object file.  The text of the warning is the contents of
 663 // the section.  This is not precisely the definition used by the old
 664 // GNU linker; the old GNU linker treated an occurrence of
 665 // .gnu.warning.SYM as defining a warning symbol.  A warning symbol
 666 // would trigger a warning on any reference.  However, it was
 667 // inconsistent in that a warning in a dynamic object only triggered
 668 // if there was no definition in a regular object.  This linker is
 669 // different in that we only issue a warning if we use the symbol
 670 // definition from the same object file as the warning section.
 671
 672 class Warnings
 673 {
 674  public:
 675   Warnings()
 676     : warnings_()
 677   { }
 678
 679   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 680   void
 681   add_warning(Symbol_table* symtab, const char* name, Object* obj,
 682               unsigned int shndx);
 683
 684   // For each symbol for which we should give a warning, make a note
 685   // on the symbol.
 686   void
 687   note_warnings(Symbol_table* symtab);
 688
 689   // Issue a warning for a reference to SYM at LOCATION.
 690   void
 691   issue_warning(const Symbol* sym, const std::string& location) const;
 692
 693  private:
 694   Warnings(const Warnings&);
 695   Warnings& operator=(const Warnings&);
 696
 697   // What we need to know to get the warning text.
 698   struct Warning_location
 699   {
 700     // The object the warning is in.
 701     Object* object;
 702     // The index of the warning section.
 703     unsigned int shndx;
 704     // The warning text if we have already loaded it.
 705     std::string text;
 706
 707     Warning_location()
 708       : object(NULL), shndx(0), text()
 709     { }
 710
 711     void
 712     set(Object* o, unsigned int s)
 713     {
 714       this->object = o;
 715       this->shndx = s;
 716     }
 717
 718     void
 719     set_text(const char* t, off_t l)
 720     { this->text.assign(t, l); }
 721   };
 722
 723   // A mapping from warning symbol names (canonicalized in
 724   // Symbol_table's namepool_ field) to
 725   typedef Unordered_map<const char*, Warning_location> Warning_table;
 726
 727   Warning_table warnings_;
 728 };
 729
 730 // The main linker symbol table.
 731
 732 class Symbol_table
 733 {
 734  public:
 735   Symbol_table();
 736
 737   ~Symbol_table();
 738
 739   // Add COUNT external symbols from the relocatable object RELOBJ to
 740   // the symbol table.  SYMS is the symbols, SYM_NAMES is their names,
 741   // SYM_NAME_SIZE is the size of SYM_NAMES.  This sets SYMPOINTERS to
 742   // point to the symbols in the symbol table.
 743   template<int size, bool big_endian>
 744   void
 745   add_from_relobj(Sized_relobj<size, big_endian>* relobj,
 746                   const unsigned char* syms, size_t count,
 747                   const char* sym_names, size_t sym_name_size,
 748                   Symbol** sympointers);
 749
 750   // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
 751   // symbol table.  SYMS is the symbols.  SYM_NAMES is their names.
 752   // SYM_NAME_SIZE is the size of SYM_NAMES.  The other parameters are
 753   // symbol version data.
 754   template<int size, bool big_endian>
 755   void
 756   add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
 757                   const unsigned char* syms, size_t count,
 758                   const char* sym_names, size_t sym_name_size,
 759                   const unsigned char* versym, size_t versym_size,
 760                   const std::vector<const char*>*);
 761
 762   // Define a special symbol based on an Output_data.  It is a
 763   // multiple definition error if this symbol is already defined.
 764   Symbol*
 765   define_in_output_data(const Target*, const char* name, const char* version,
 766                         Output_data*, uint64_t value, uint64_t symsize,
 767                         elfcpp::STT type, elfcpp::STB binding,
 768                         elfcpp::STV visibility, unsigned char nonvis,
 769                         bool offset_is_from_end, bool only_if_ref);
 770
 771   // Define a special symbol based on an Output_segment.  It is a
 772   // multiple definition error if this symbol is already defined.
 773   Symbol*
 774   define_in_output_segment(const Target*, const char* name,
 775                            const char* version, Output_segment*,
 776                            uint64_t value, uint64_t symsize,
 777                            elfcpp::STT type, elfcpp::STB binding,
 778                            elfcpp::STV visibility, unsigned char nonvis,
 779                            Symbol::Segment_offset_base, bool only_if_ref);
 780
 781   // Define a special symbol with a constant value.  It is a multiple
 782   // definition error if this symbol is already defined.
 783   Symbol*
 784   define_as_constant(const Target*, const char* name, const char* version,
 785                      uint64_t value, uint64_t symsize, elfcpp::STT type,
 786                      elfcpp::STB binding, elfcpp::STV visibility,
 787                      unsigned char nonvis, bool only_if_ref);
 788
 789   // Define a set of symbols in output sections.
 790   void
 791   define_symbols(const Layout*, const Target*, int count,
 792                  const Define_symbol_in_section*);
 793
 794   // Define a set of symbols in output segments.
 795   void
 796   define_symbols(const Layout*, const Target*, int count,
 797                  const Define_symbol_in_segment*);
 798
 799   // Look up a symbol.
 800   Symbol*
 801   lookup(const char*, const char* version = NULL) const;
 802
 803   // Return the real symbol associated with the forwarder symbol FROM.
 804   Symbol*
 805   resolve_forwards(const Symbol* from) const;
 806
 807   // Return the bitsize (32 or 64) of the symbols in the table.
 808   int
 809   get_size() const
 810   { return this->size_; }
 811
 812   // Return the sized version of a symbol in this table.
 813   template<int size>
 814   Sized_symbol<size>*
 815   get_sized_symbol(Symbol* ACCEPT_SIZE) const;
 816
 817   template<int size>
 818   const Sized_symbol<size>*
 819   get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
 820
 821   // Return the count of undefined symbols seen.
 822   int
 823   saw_undefined() const
 824   { return this->saw_undefined_; }
 825
 826   // Allocate the common symbols
 827   void
 828   allocate_commons(const General_options&, Layout*);
 829
 830   // Add a warning for symbol NAME in section SHNDX in object OBJ.
 831   void
 832   add_warning(const char* name, Object* obj, unsigned int shndx)
 833   { this->warnings_.add_warning(this, name, obj, shndx); }
 834
 835   // Canonicalize a symbol name for use in the hash table.
 836   const char*
 837   canonicalize_name(const char* name)
 838   { return this->namepool_.add(name, NULL); }
 839
 840   // Possibly issue a warning for a reference to SYM at LOCATION which
 841   // is in OBJ.
 842   void
 843   issue_warning(const Symbol* sym, const std::string& location) const
 844   { this->warnings_.issue_warning(sym, location); }
 845
 846   // Set the dynamic symbol indexes.  INDEX is the index of the first
 847   // global dynamic symbol.  Pointers to the symbols are stored into
 848   // the vector.  The names are stored into the Stringpool.  This
 849   // returns an updated dynamic symbol index.
 850   unsigned int
 851   set_dynsym_indexes(const General_options*, const Target*, unsigned int index,
 852                      std::vector<Symbol*>*, Stringpool*, Versions*);
 853
 854   // Finalize the symbol table after we have set the final addresses
 855   // of all the input sections.  This sets the final symbol indexes,
 856   // values and adds the names to *POOL.  INDEX is the index of the
 857   // first global symbol.  OFF is the file offset of the global symbol
 858   // table, DYNOFF is the offset of the globals in the dynamic symbol
 859   // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
 860   // symbol, and DYNCOUNT is the number of global dynamic symbols.
 861   // This records the parameters, and returns the new file offset.
 862   off_t
 863   finalize(unsigned int index, off_t off, off_t dynoff,
 864            size_t dyn_global_index, size_t dyncount, Stringpool* pool);
 865
 866   // Write out the global symbols.
 867   void
 868   write_globals(const Target*, const Stringpool*, const Stringpool*,
 869                 Output_file*) const;
 870
 871   // Write out a section symbol.  Return the updated offset.
 872   void
 873   write_section_symbol(const Target*, const Output_section*, Output_file*,
 874                        off_t) const;
 875
 876  private:
 877   Symbol_table(const Symbol_table&);
 878   Symbol_table& operator=(const Symbol_table&);
 879
 880   // Set the size (32 or 64) of the symbols in the table.
 881   void
 882   set_size(int size)
 883   { this->size_ = size; }
 884
 885   // Make FROM a forwarder symbol to TO.
 886   void
 887   make_forwarder(Symbol* from, Symbol* to);
 888
 889   // Add a symbol.
 890   template<int size, bool big_endian>
 891   Symbol*
 892   add_from_object(Object*, const char *name, Stringpool::Key name_key,
 893                   const char *version, Stringpool::Key version_key,
 894                   bool def, const elfcpp::Sym<size, big_endian>& sym);
 895
 896   // Resolve symbols.
 897   template<int size, bool big_endian>
 898   static void
 899   resolve(Sized_symbol<size>* to,
 900           const elfcpp::Sym<size, big_endian>& sym,
 901           Object*, const char* version);
 902
 903   template<int size, bool big_endian>
 904   static void
 905   resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
 906           const char* version ACCEPT_SIZE_ENDIAN);
 907
 908   // Define a special symbol.
 909   template<int size, bool big_endian>
 910   Sized_symbol<size>*
 911   define_special_symbol(const Target* target, const char* name,
 912                         const char* version, bool only_if_ref
 913                         ACCEPT_SIZE_ENDIAN);
 914
 915   // Define a symbol in an Output_data, sized version.
 916   template<int size>
 917   Sized_symbol<size>*
 918   do_define_in_output_data(const Target*, const char* name,
 919                            const char* version, Output_data*,
 920                            typename elfcpp::Elf_types<size>::Elf_Addr value,
 921                            typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 922                            elfcpp::STT type, elfcpp::STB binding,
 923                            elfcpp::STV visibility, unsigned char nonvis,
 924                            bool offset_is_from_end, bool only_if_ref);
 925
 926   // Define a symbol in an Output_segment, sized version.
 927   template<int size>
 928   Sized_symbol<size>*
 929   do_define_in_output_segment(
 930     const Target*, const char* name, const char* version, Output_segment* os,
 931     typename elfcpp::Elf_types<size>::Elf_Addr value,
 932     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 933     elfcpp::STT type, elfcpp::STB binding,
 934     elfcpp::STV visibility, unsigned char nonvis,
 935     Symbol::Segment_offset_base offset_base, bool only_if_ref);
 936
 937   // Define a symbol as a constant, sized version.
 938   template<int size>
 939   Sized_symbol<size>*
 940   do_define_as_constant(
 941     const Target*, const char* name, const char* version,
 942     typename elfcpp::Elf_types<size>::Elf_Addr value,
 943     typename elfcpp::Elf_types<size>::Elf_WXword ssize,
 944     elfcpp::STT type, elfcpp::STB binding,
 945     elfcpp::STV visibility, unsigned char nonvis,
 946     bool only_if_ref);
 947
 948   // Allocate the common symbols, sized version.
 949   template<int size>
 950   void
 951   do_allocate_commons(const General_options&, Layout*);
 952
 953   // Finalize symbols specialized for size.
 954   template<int size>
 955   off_t
 956   sized_finalize(unsigned int, off_t, Stringpool*);
 957
 958   // Write globals specialized for size and endianness.
 959   template<int size, bool big_endian>
 960   void
 961   sized_write_globals(const Target*, const Stringpool*, const Stringpool*,
 962                       Output_file*) const;
 963
 964   // Write out a symbol to P.
 965   template<int size, bool big_endian>
 966   void
 967   sized_write_symbol(Sized_symbol<size>*, unsigned int shndx,
 968                      const Stringpool*, unsigned char* p
 969                      ACCEPT_SIZE_ENDIAN) const;
 970
 971   // Write out a section symbol, specialized for size and endianness.
 972   template<int size, bool big_endian>
 973   void
 974   sized_write_section_symbol(const Output_section*, Output_file*, off_t) const;
 975
 976   // The type of the symbol hash table.
 977
 978   typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
 979
 980   struct Symbol_table_hash
 981   {
 982     size_t
 983     operator()(const Symbol_table_key&) const;
 984   };
 985
 986   struct Symbol_table_eq
 987   {
 988     bool
 989     operator()(const Symbol_table_key&, const Symbol_table_key&) const;
 990   };
 991
 992   typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
 993                         Symbol_table_eq> Symbol_table_type;
 994
 995   // The type of the list of common symbols.
 996
 997   typedef std::vector<Symbol*> Commons_type;
 998
 999   // The size of the symbols in the symbol table (32 or 64).
1000   int size_;
1001
1002   // We increment this every time we see a new undefined symbol, for
1003   // use in archive groups.
1004   int saw_undefined_;
1005
1006   // The index of the first global symbol in the output file.
1007   unsigned int first_global_index_;
1008
1009   // The file offset within the output symtab section where we should
1010   // write the table.
1011   off_t offset_;
1012
1013   // The number of global symbols we want to write out.
1014   size_t output_count_;
1015
1016   // The file offset of the global dynamic symbols, or 0 if none.
1017   off_t dynamic_offset_;
1018
1019   // The index of the first global dynamic symbol.
1020   unsigned int first_dynamic_global_index_;
1021
1022   // The number of global dynamic symbols, or 0 if none.
1023   off_t dynamic_count_;
1024
1025   // The symbol hash table.
1026   Symbol_table_type table_;
1027
1028   // A pool of symbol names.  This is used for all global symbols.
1029   // Entries in the hash table point into this pool.
1030   Stringpool namepool_;
1031
1032   // Forwarding symbols.
1033   Unordered_map<const Symbol*, Symbol*> forwarders_;
1034
1035   // We don't expect there to be very many common symbols, so we keep
1036   // a list of them.  When we find a common symbol we add it to this
1037   // list.  It is possible that by the time we process the list the
1038   // symbol is no longer a common symbol.  It may also have become a
1039   // forwarder.
1040   Commons_type commons_;
1041
1042   // Manage symbol warnings.
1043   Warnings warnings_;
1044 };
1045
1046 // We inline get_sized_symbol for efficiency.
1047
1048 template<int size>
1049 Sized_symbol<size>*
1050 Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const
1051 {
1052   gold_assert(size == this->get_size());
1053   return static_cast<Sized_symbol<size>*>(sym);
1054 }
1055
1056 template<int size>
1057 const Sized_symbol<size>*
1058 Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const
1059 {
1060   gold_assert(size == this->get_size());
1061   return static_cast<const Sized_symbol<size>*>(sym);
1062 }
1063
1064 } // End namespace gold.
1065
1066 #endif // !defined(GOLD_SYMTAB_H)