gold/symtab.cc

   1 // symtab.cc -- the gold symbol table
   2
   3 // Copyright (C) 2006-2015 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26 #include <stdint.h>
  27 #include <algorithm>
  28 #include <set>
  29 #include <string>
  30 #include <utility>
  31 #include "demangle.h"
  32
  33 #include "gc.h"
  34 #include "object.h"
  35 #include "dwarf_reader.h"
  36 #include "dynobj.h"
  37 #include "output.h"
  38 #include "target.h"
  39 #include "workqueue.h"
  40 #include "symtab.h"
  41 #include "script.h"
  42 #include "plugin.h"
  43 #include "incremental.h"
  44
  45 namespace gold
  46 {
  47
  48 // Class Symbol.
  49
  50 // Initialize fields in Symbol.  This initializes everything except u_
  51 // and source_.
  52
  53 void
  54 Symbol::init_fields(const char* name, const char* version,
  55                     elfcpp::STT type, elfcpp::STB binding,
  56                     elfcpp::STV visibility, unsigned char nonvis)
  57 {
  58   this->name_ = name;
  59   this->version_ = version;
  60   this->symtab_index_ = 0;
  61   this->dynsym_index_ = 0;
  62   this->got_offsets_.init();
  63   this->plt_offset_ = -1U;
  64   this->type_ = type;
  65   this->binding_ = binding;
  66   this->visibility_ = visibility;
  67   this->nonvis_ = nonvis;
  68   this->is_def_ = false;
  69   this->is_forwarder_ = false;
  70   this->has_alias_ = false;
  71   this->needs_dynsym_entry_ = false;
  72   this->in_reg_ = false;
  73   this->in_dyn_ = false;
  74   this->has_warning_ = false;
  75   this->is_copied_from_dynobj_ = false;
  76   this->is_forced_local_ = false;
  77   this->is_ordinary_shndx_ = false;
  78   this->in_real_elf_ = false;
  79   this->is_defined_in_discarded_section_ = false;
  80   this->undef_binding_set_ = false;
  81   this->undef_binding_weak_ = false;
  82   this->is_predefined_ = false;
  83 }
  84
  85 // Return the demangled version of the symbol's name, but only
  86 // if the --demangle flag was set.
  87
  88 static std::string
  89 demangle(const char* name)
  90 {
  91   if (!parameters->options().do_demangle())
  92     return name;
  93
  94   // cplus_demangle allocates memory for the result it returns,
  95   // and returns NULL if the name is already demangled.
  96   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
  97   if (demangled_name == NULL)
  98     return name;
  99
 100   std::string retval(demangled_name);
 101   free(demangled_name);
 102   return retval;
 103 }
 104
 105 std::string
 106 Symbol::demangled_name() const
 107 {
 108   return demangle(this->name());
 109 }
 110
 111 // Initialize the fields in the base class Symbol for SYM in OBJECT.
 112
 113 template<int size, bool big_endian>
 114 void
 115 Symbol::init_base_object(const char* name, const char* version, Object* object,
 116                          const elfcpp::Sym<size, big_endian>& sym,
 117                          unsigned int st_shndx, bool is_ordinary)
 118 {
 119   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
 120                     sym.get_st_visibility(), sym.get_st_nonvis());
 121   this->u_.from_object.object = object;
 122   this->u_.from_object.shndx = st_shndx;
 123   this->is_ordinary_shndx_ = is_ordinary;
 124   this->source_ = FROM_OBJECT;
 125   this->in_reg_ = !object->is_dynamic();
 126   this->in_dyn_ = object->is_dynamic();
 127   this->in_real_elf_ = object->pluginobj() == NULL;
 128 }
 129
 130 // Initialize the fields in the base class Symbol for a symbol defined
 131 // in an Output_data.
 132
 133 void
 134 Symbol::init_base_output_data(const char* name, const char* version,
 135                               Output_data* od, elfcpp::STT type,
 136                               elfcpp::STB binding, elfcpp::STV visibility,
 137                               unsigned char nonvis, bool offset_is_from_end,
 138                               bool is_predefined)
 139 {
 140   this->init_fields(name, version, type, binding, visibility, nonvis);
 141   this->u_.in_output_data.output_data = od;
 142   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
 143   this->source_ = IN_OUTPUT_DATA;
 144   this->in_reg_ = true;
 145   this->in_real_elf_ = true;
 146   this->is_predefined_ = is_predefined;
 147 }
 148
 149 // Initialize the fields in the base class Symbol for a symbol defined
 150 // in an Output_segment.
 151
 152 void
 153 Symbol::init_base_output_segment(const char* name, const char* version,
 154                                  Output_segment* os, elfcpp::STT type,
 155                                  elfcpp::STB binding, elfcpp::STV visibility,
 156                                  unsigned char nonvis,
 157                                  Segment_offset_base offset_base,
 158                                  bool is_predefined)
 159 {
 160   this->init_fields(name, version, type, binding, visibility, nonvis);
 161   this->u_.in_output_segment.output_segment = os;
 162   this->u_.in_output_segment.offset_base = offset_base;
 163   this->source_ = IN_OUTPUT_SEGMENT;
 164   this->in_reg_ = true;
 165   this->in_real_elf_ = true;
 166   this->is_predefined_ = is_predefined;
 167 }
 168
 169 // Initialize the fields in the base class Symbol for a symbol defined
 170 // as a constant.
 171
 172 void
 173 Symbol::init_base_constant(const char* name, const char* version,
 174                            elfcpp::STT type, elfcpp::STB binding,
 175                            elfcpp::STV visibility, unsigned char nonvis,
 176                            bool is_predefined)
 177 {
 178   this->init_fields(name, version, type, binding, visibility, nonvis);
 179   this->source_ = IS_CONSTANT;
 180   this->in_reg_ = true;
 181   this->in_real_elf_ = true;
 182   this->is_predefined_ = is_predefined;
 183 }
 184
 185 // Initialize the fields in the base class Symbol for an undefined
 186 // symbol.
 187
 188 void
 189 Symbol::init_base_undefined(const char* name, const char* version,
 190                             elfcpp::STT type, elfcpp::STB binding,
 191                             elfcpp::STV visibility, unsigned char nonvis)
 192 {
 193   this->init_fields(name, version, type, binding, visibility, nonvis);
 194   this->dynsym_index_ = -1U;
 195   this->source_ = IS_UNDEFINED;
 196   this->in_reg_ = true;
 197   this->in_real_elf_ = true;
 198 }
 199
 200 // Allocate a common symbol in the base.
 201
 202 void
 203 Symbol::allocate_base_common(Output_data* od)
 204 {
 205   gold_assert(this->is_common());
 206   this->source_ = IN_OUTPUT_DATA;
 207   this->u_.in_output_data.output_data = od;
 208   this->u_.in_output_data.offset_is_from_end = false;
 209 }
 210
 211 // Initialize the fields in Sized_symbol for SYM in OBJECT.
 212
 213 template<int size>
 214 template<bool big_endian>
 215 void
 216 Sized_symbol<size>::init_object(const char* name, const char* version,
 217                                 Object* object,
 218                                 const elfcpp::Sym<size, big_endian>& sym,
 219                                 unsigned int st_shndx, bool is_ordinary)
 220 {
 221   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
 222   this->value_ = sym.get_st_value();
 223   this->symsize_ = sym.get_st_size();
 224 }
 225
 226 // Initialize the fields in Sized_symbol for a symbol defined in an
 227 // Output_data.
 228
 229 template<int size>
 230 void
 231 Sized_symbol<size>::init_output_data(const char* name, const char* version,
 232                                      Output_data* od, Value_type value,
 233                                      Size_type symsize, elfcpp::STT type,
 234                                      elfcpp::STB binding,
 235                                      elfcpp::STV visibility,
 236                                      unsigned char nonvis,
 237                                      bool offset_is_from_end,
 238                                      bool is_predefined)
 239 {
 240   this->init_base_output_data(name, version, od, type, binding, visibility,
 241                               nonvis, offset_is_from_end, is_predefined);
 242   this->value_ = value;
 243   this->symsize_ = symsize;
 244 }
 245
 246 // Initialize the fields in Sized_symbol for a symbol defined in an
 247 // Output_segment.
 248
 249 template<int size>
 250 void
 251 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
 252                                         Output_segment* os, Value_type value,
 253                                         Size_type symsize, elfcpp::STT type,
 254                                         elfcpp::STB binding,
 255                                         elfcpp::STV visibility,
 256                                         unsigned char nonvis,
 257                                         Segment_offset_base offset_base,
 258                                         bool is_predefined)
 259 {
 260   this->init_base_output_segment(name, version, os, type, binding, visibility,
 261                                  nonvis, offset_base, is_predefined);
 262   this->value_ = value;
 263   this->symsize_ = symsize;
 264 }
 265
 266 // Initialize the fields in Sized_symbol for a symbol defined as a
 267 // constant.
 268
 269 template<int size>
 270 void
 271 Sized_symbol<size>::init_constant(const char* name, const char* version,
 272                                   Value_type value, Size_type symsize,
 273                                   elfcpp::STT type, elfcpp::STB binding,
 274                                   elfcpp::STV visibility, unsigned char nonvis,
 275                                   bool is_predefined)
 276 {
 277   this->init_base_constant(name, version, type, binding, visibility, nonvis,
 278                            is_predefined);
 279   this->value_ = value;
 280   this->symsize_ = symsize;
 281 }
 282
 283 // Initialize the fields in Sized_symbol for an undefined symbol.
 284
 285 template<int size>
 286 void
 287 Sized_symbol<size>::init_undefined(const char* name, const char* version,
 288                                    elfcpp::STT type, elfcpp::STB binding,
 289                                    elfcpp::STV visibility, unsigned char nonvis)
 290 {
 291   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
 292   this->value_ = 0;
 293   this->symsize_ = 0;
 294 }
 295
 296 // Return an allocated string holding the symbol's name as
 297 // name@version.  This is used for relocatable links.
 298
 299 std::string
 300 Symbol::versioned_name() const
 301 {
 302   gold_assert(this->version_ != NULL);
 303   std::string ret = this->name_;
 304   ret.push_back('@');
 305   if (this->is_def_)
 306     ret.push_back('@');
 307   ret += this->version_;
 308   return ret;
 309 }
 310
 311 // Return true if SHNDX represents a common symbol.
 312
 313 bool
 314 Symbol::is_common_shndx(unsigned int shndx)
 315 {
 316   return (shndx == elfcpp::SHN_COMMON
 317           || shndx == parameters->target().small_common_shndx()
 318           || shndx == parameters->target().large_common_shndx());
 319 }
 320
 321 // Allocate a common symbol.
 322
 323 template<int size>
 324 void
 325 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
 326 {
 327   this->allocate_base_common(od);
 328   this->value_ = value;
 329 }
 330
 331 // The ""'s around str ensure str is a string literal, so sizeof works.
 332 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
 333
 334 // Return true if this symbol should be added to the dynamic symbol
 335 // table.
 336
 337 bool
 338 Symbol::should_add_dynsym_entry(Symbol_table* symtab) const
 339 {
 340   // If the symbol is only present on plugin files, the plugin decided we
 341   // don't need it.
 342   if (!this->in_real_elf())
 343     return false;
 344
 345   // If the symbol is used by a dynamic relocation, we need to add it.
 346   if (this->needs_dynsym_entry())
 347     return true;
 348
 349   // If this symbol's section is not added, the symbol need not be added.
 350   // The section may have been GCed.  Note that export_dynamic is being
 351   // overridden here.  This should not be done for shared objects.
 352   if (parameters->options().gc_sections()
 353       && !parameters->options().shared()
 354       && this->source() == Symbol::FROM_OBJECT
 355       && !this->object()->is_dynamic())
 356     {
 357       Relobj* relobj = static_cast<Relobj*>(this->object());
 358       bool is_ordinary;
 359       unsigned int shndx = this->shndx(&is_ordinary);
 360       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
 361           && !relobj->is_section_included(shndx)
 362           && !symtab->is_section_folded(relobj, shndx))
 363         return false;
 364     }
 365
 366   // If the symbol was forced dynamic in a --dynamic-list file
 367   // or an --export-dynamic-symbol option, add it.
 368   if (!this->is_from_dynobj()
 369       && (parameters->options().in_dynamic_list(this->name())
 370           || parameters->options().is_export_dynamic_symbol(this->name())))
 371     {
 372       if (!this->is_forced_local())
 373         return true;
 374       gold_warning(_("Cannot export local symbol '%s'"),
 375                    this->demangled_name().c_str());
 376       return false;
 377     }
 378
 379   // If the symbol was forced local in a version script, do not add it.
 380   if (this->is_forced_local())
 381     return false;
 382
 383   // If dynamic-list-data was specified, add any STT_OBJECT.
 384   if (parameters->options().dynamic_list_data()
 385       && !this->is_from_dynobj()
 386       && this->type() == elfcpp::STT_OBJECT)
 387     return true;
 388
 389   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
 390   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
 391   if ((parameters->options().dynamic_list_cpp_new()
 392        || parameters->options().dynamic_list_cpp_typeinfo())
 393       && !this->is_from_dynobj())
 394     {
 395       // TODO(csilvers): We could probably figure out if we're an operator
 396       //                 new/delete or typeinfo without the need to demangle.
 397       char* demangled_name = cplus_demangle(this->name(),
 398                                             DMGL_ANSI | DMGL_PARAMS);
 399       if (demangled_name == NULL)
 400         {
 401           // Not a C++ symbol, so it can't satisfy these flags
 402         }
 403       else if (parameters->options().dynamic_list_cpp_new()
 404                && (strprefix(demangled_name, "operator new")
 405                    || strprefix(demangled_name, "operator delete")))
 406         {
 407           free(demangled_name);
 408           return true;
 409         }
 410       else if (parameters->options().dynamic_list_cpp_typeinfo()
 411                && (strprefix(demangled_name, "typeinfo name for")
 412                    || strprefix(demangled_name, "typeinfo for")))
 413         {
 414           free(demangled_name);
 415           return true;
 416         }
 417       else
 418         free(demangled_name);
 419     }
 420
 421   // If exporting all symbols or building a shared library,
 422   // and the symbol is defined in a regular object and is
 423   // externally visible, we need to add it.
 424   if ((parameters->options().export_dynamic() || parameters->options().shared())
 425       && !this->is_from_dynobj()
 426       && !this->is_undefined()
 427       && this->is_externally_visible())
 428     return true;
 429
 430   return false;
 431 }
 432
 433 // Return true if the final value of this symbol is known at link
 434 // time.
 435
 436 bool
 437 Symbol::final_value_is_known() const
 438 {
 439   // If we are not generating an executable, then no final values are
 440   // known, since they will change at runtime, with the exception of
 441   // TLS symbols in a position-independent executable.
 442   if ((parameters->options().output_is_position_independent()
 443        || parameters->options().relocatable())
 444       && !(this->type() == elfcpp::STT_TLS
 445            && parameters->options().pie()))
 446     return false;
 447
 448   // If the symbol is not from an object file, and is not undefined,
 449   // then it is defined, and known.
 450   if (this->source_ != FROM_OBJECT)
 451     {
 452       if (this->source_ != IS_UNDEFINED)
 453         return true;
 454     }
 455   else
 456     {
 457       // If the symbol is from a dynamic object, then the final value
 458       // is not known.
 459       if (this->object()->is_dynamic())
 460         return false;
 461
 462       // If the symbol is not undefined (it is defined or common),
 463       // then the final value is known.
 464       if (!this->is_undefined())
 465         return true;
 466     }
 467
 468   // If the symbol is undefined, then whether the final value is known
 469   // depends on whether we are doing a static link.  If we are doing a
 470   // dynamic link, then the final value could be filled in at runtime.
 471   // This could reasonably be the case for a weak undefined symbol.
 472   return parameters->doing_static_link();
 473 }
 474
 475 // Return the output section where this symbol is defined.
 476
 477 Output_section*
 478 Symbol::output_section() const
 479 {
 480   switch (this->source_)
 481     {
 482     case FROM_OBJECT:
 483       {
 484         unsigned int shndx = this->u_.from_object.shndx;
 485         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
 486           {
 487             gold_assert(!this->u_.from_object.object->is_dynamic());
 488             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
 489             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
 490             return relobj->output_section(shndx);
 491           }
 492         return NULL;
 493       }
 494
 495     case IN_OUTPUT_DATA:
 496       return this->u_.in_output_data.output_data->output_section();
 497
 498     case IN_OUTPUT_SEGMENT:
 499     case IS_CONSTANT:
 500     case IS_UNDEFINED:
 501       return NULL;
 502
 503     default:
 504       gold_unreachable();
 505     }
 506 }
 507
 508 // Set the symbol's output section.  This is used for symbols defined
 509 // in scripts.  This should only be called after the symbol table has
 510 // been finalized.
 511
 512 void
 513 Symbol::set_output_section(Output_section* os)
 514 {
 515   switch (this->source_)
 516     {
 517     case FROM_OBJECT:
 518     case IN_OUTPUT_DATA:
 519       gold_assert(this->output_section() == os);
 520       break;
 521     case IS_CONSTANT:
 522       this->source_ = IN_OUTPUT_DATA;
 523       this->u_.in_output_data.output_data = os;
 524       this->u_.in_output_data.offset_is_from_end = false;
 525       break;
 526     case IN_OUTPUT_SEGMENT:
 527     case IS_UNDEFINED:
 528     default:
 529       gold_unreachable();
 530     }
 531 }
 532
 533 // Set the symbol's output segment.  This is used for pre-defined
 534 // symbols whose segments aren't known until after layout is done
 535 // (e.g., __ehdr_start).
 536
 537 void
 538 Symbol::set_output_segment(Output_segment* os, Segment_offset_base base)
 539 {
 540   gold_assert(this->is_predefined_);
 541   this->source_ = IN_OUTPUT_SEGMENT;
 542   this->u_.in_output_segment.output_segment = os;
 543   this->u_.in_output_segment.offset_base = base;
 544 }
 545
 546 // Set the symbol to undefined.  This is used for pre-defined
 547 // symbols whose segments aren't known until after layout is done
 548 // (e.g., __ehdr_start).
 549
 550 void
 551 Symbol::set_undefined()
 552 {
 553   this->source_ = IS_UNDEFINED;
 554   this->is_predefined_ = false;
 555 }
 556
 557 // Class Symbol_table.
 558
 559 Symbol_table::Symbol_table(unsigned int count,
 560                            const Version_script_info& version_script)
 561   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
 562     forwarders_(), commons_(), tls_commons_(), small_commons_(),
 563     large_commons_(), forced_locals_(), warnings_(),
 564     version_script_(version_script), gc_(NULL), icf_(NULL)
 565 {
 566   namepool_.reserve(count);
 567 }
 568
 569 Symbol_table::~Symbol_table()
 570 {
 571 }
 572
 573 // The symbol table key equality function.  This is called with
 574 // Stringpool keys.
 575
 576 inline bool
 577 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
 578                                           const Symbol_table_key& k2) const
 579 {
 580   return k1.first == k2.first && k1.second == k2.second;
 581 }
 582
 583 bool
 584 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
 585 {
 586   return (parameters->options().icf_enabled()
 587           && this->icf_->is_section_folded(obj, shndx));
 588 }
 589
 590 // For symbols that have been listed with a -u or --export-dynamic-symbol
 591 // option, add them to the work list to avoid gc'ing them.
 592
 593 void
 594 Symbol_table::gc_mark_undef_symbols(Layout* layout)
 595 {
 596   for (options::String_set::const_iterator p =
 597          parameters->options().undefined_begin();
 598        p != parameters->options().undefined_end();
 599        ++p)
 600     {
 601       const char* name = p->c_str();
 602       Symbol* sym = this->lookup(name);
 603       gold_assert(sym != NULL);
 604       if (sym->source() == Symbol::FROM_OBJECT
 605           && !sym->object()->is_dynamic())
 606         {
 607           this->gc_mark_symbol(sym);
 608         }
 609     }
 610
 611   for (options::String_set::const_iterator p =
 612          parameters->options().export_dynamic_symbol_begin();
 613        p != parameters->options().export_dynamic_symbol_end();
 614        ++p)
 615     {
 616       const char* name = p->c_str();
 617       Symbol* sym = this->lookup(name);
 618       // It's not an error if a symbol named by --export-dynamic-symbol
 619       // is undefined.
 620       if (sym != NULL
 621           && sym->source() == Symbol::FROM_OBJECT
 622           && !sym->object()->is_dynamic())
 623         {
 624           this->gc_mark_symbol(sym);
 625         }
 626     }
 627
 628   for (Script_options::referenced_const_iterator p =
 629          layout->script_options()->referenced_begin();
 630        p != layout->script_options()->referenced_end();
 631        ++p)
 632     {
 633       Symbol* sym = this->lookup(p->c_str());
 634       gold_assert(sym != NULL);
 635       if (sym->source() == Symbol::FROM_OBJECT
 636           && !sym->object()->is_dynamic())
 637         {
 638           this->gc_mark_symbol(sym);
 639         }
 640     }
 641 }
 642
 643 void
 644 Symbol_table::gc_mark_symbol(Symbol* sym)
 645 {
 646   // Add the object and section to the work list.
 647   bool is_ordinary;
 648   unsigned int shndx = sym->shndx(&is_ordinary);
 649   if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
 650     {
 651       gold_assert(this->gc_!= NULL);
 652       this->gc_->worklist().push_back(Section_id(sym->object(), shndx));
 653     }
 654   parameters->target().gc_mark_symbol(this, sym);
 655 }
 656
 657 // When doing garbage collection, keep symbols that have been seen in
 658 // dynamic objects.
 659 inline void
 660 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
 661 {
 662   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
 663       && !sym->object()->is_dynamic())
 664     this->gc_mark_symbol(sym);
 665 }
 666
 667 // Make TO a symbol which forwards to FROM.
 668
 669 void
 670 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
 671 {
 672   gold_assert(from != to);
 673   gold_assert(!from->is_forwarder() && !to->is_forwarder());
 674   this->forwarders_[from] = to;
 675   from->set_forwarder();
 676 }
 677
 678 // Resolve the forwards from FROM, returning the real symbol.
 679
 680 Symbol*
 681 Symbol_table::resolve_forwards(const Symbol* from) const
 682 {
 683   gold_assert(from->is_forwarder());
 684   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
 685     this->forwarders_.find(from);
 686   gold_assert(p != this->forwarders_.end());
 687   return p->second;
 688 }
 689
 690 // Look up a symbol by name.
 691
 692 Symbol*
 693 Symbol_table::lookup(const char* name, const char* version) const
 694 {
 695   Stringpool::Key name_key;
 696   name = this->namepool_.find(name, &name_key);
 697   if (name == NULL)
 698     return NULL;
 699
 700   Stringpool::Key version_key = 0;
 701   if (version != NULL)
 702     {
 703       version = this->namepool_.find(version, &version_key);
 704       if (version == NULL)
 705         return NULL;
 706     }
 707
 708   Symbol_table_key key(name_key, version_key);
 709   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
 710   if (p == this->table_.end())
 711     return NULL;
 712   return p->second;
 713 }
 714
 715 // Resolve a Symbol with another Symbol.  This is only used in the
 716 // unusual case where there are references to both an unversioned
 717 // symbol and a symbol with a version, and we then discover that that
 718 // version is the default version.  Because this is unusual, we do
 719 // this the slow way, by converting back to an ELF symbol.
 720
 721 template<int size, bool big_endian>
 722 void
 723 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
 724 {
 725   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
 726   elfcpp::Sym_write<size, big_endian> esym(buf);
 727   // We don't bother to set the st_name or the st_shndx field.
 728   esym.put_st_value(from->value());
 729   esym.put_st_size(from->symsize());
 730   esym.put_st_info(from->binding(), from->type());
 731   esym.put_st_other(from->visibility(), from->nonvis());
 732   bool is_ordinary;
 733   unsigned int shndx = from->shndx(&is_ordinary);
 734   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
 735                 from->version());
 736   if (from->in_reg())
 737     to->set_in_reg();
 738   if (from->in_dyn())
 739     to->set_in_dyn();
 740   if (parameters->options().gc_sections())
 741     this->gc_mark_dyn_syms(to);
 742 }
 743
 744 // Record that a symbol is forced to be local by a version script or
 745 // by visibility.
 746
 747 void
 748 Symbol_table::force_local(Symbol* sym)
 749 {
 750   if (!sym->is_defined() && !sym->is_common())
 751     return;
 752   if (sym->is_forced_local())
 753     {
 754       // We already got this one.
 755       return;
 756     }
 757   sym->set_is_forced_local();
 758   this->forced_locals_.push_back(sym);
 759 }
 760
 761 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
 762 // is only called for undefined symbols, when at least one --wrap
 763 // option was used.
 764
 765 const char*
 766 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
 767 {
 768   // For some targets, we need to ignore a specific character when
 769   // wrapping, and add it back later.
 770   char prefix = '\0';
 771   if (name[0] == parameters->target().wrap_char())
 772     {
 773       prefix = name[0];
 774       ++name;
 775     }
 776
 777   if (parameters->options().is_wrap(name))
 778     {
 779       // Turn NAME into __wrap_NAME.
 780       std::string s;
 781       if (prefix != '\0')
 782         s += prefix;
 783       s += "__wrap_";
 784       s += name;
 785
 786       // This will give us both the old and new name in NAMEPOOL_, but
 787       // that is OK.  Only the versions we need will wind up in the
 788       // real string table in the output file.
 789       return this->namepool_.add(s.c_str(), true, name_key);
 790     }
 791
 792   const char* const real_prefix = "__real_";
 793   const size_t real_prefix_length = strlen(real_prefix);
 794   if (strncmp(name, real_prefix, real_prefix_length) == 0
 795       && parameters->options().is_wrap(name + real_prefix_length))
 796     {
 797       // Turn __real_NAME into NAME.
 798       std::string s;
 799       if (prefix != '\0')
 800         s += prefix;
 801       s += name + real_prefix_length;
 802       return this->namepool_.add(s.c_str(), true, name_key);
 803     }
 804
 805   return name;
 806 }
 807
 808 // This is called when we see a symbol NAME/VERSION, and the symbol
 809 // already exists in the symbol table, and VERSION is marked as being
 810 // the default version.  SYM is the NAME/VERSION symbol we just added.
 811 // DEFAULT_IS_NEW is true if this is the first time we have seen the
 812 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
 813
 814 template<int size, bool big_endian>
 815 void
 816 Symbol_table::define_default_version(Sized_symbol<size>* sym,
 817                                      bool default_is_new,
 818                                      Symbol_table_type::iterator pdef)
 819 {
 820   if (default_is_new)
 821     {
 822       // This is the first time we have seen NAME/NULL.  Make
 823       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
 824       // version.
 825       pdef->second = sym;
 826       sym->set_is_default();
 827     }
 828   else if (pdef->second == sym)
 829     {
 830       // NAME/NULL already points to NAME/VERSION.  Don't mark the
 831       // symbol as the default if it is not already the default.
 832     }
 833   else
 834     {
 835       // This is the unfortunate case where we already have entries
 836       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
 837       // NAME/VERSION where VERSION is the default version.  We have
 838       // already resolved this new symbol with the existing
 839       // NAME/VERSION symbol.
 840
 841       // It's possible that NAME/NULL and NAME/VERSION are both
 842       // defined in regular objects.  This can only happen if one
 843       // object file defines foo and another defines foo@@ver.  This
 844       // is somewhat obscure, but we call it a multiple definition
 845       // error.
 846
 847       // It's possible that NAME/NULL actually has a version, in which
 848       // case it won't be the same as VERSION.  This happens with
 849       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
 850       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
 851       // then see an unadorned t2_2 in an object file and give it
 852       // version VER1 from the version script.  This looks like a
 853       // default definition for VER1, so it looks like we should merge
 854       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
 855       // not obvious that this is an error, either.  So we just punt.
 856
 857       // If one of the symbols has non-default visibility, and the
 858       // other is defined in a shared object, then they are different
 859       // symbols.
 860
 861       // Otherwise, we just resolve the symbols as though they were
 862       // the same.
 863
 864       if (pdef->second->version() != NULL)
 865         gold_assert(pdef->second->version() != sym->version());
 866       else if (sym->visibility() != elfcpp::STV_DEFAULT
 867                && pdef->second->is_from_dynobj())
 868         ;
 869       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
 870                && sym->is_from_dynobj())
 871         ;
 872       else
 873         {
 874           const Sized_symbol<size>* symdef;
 875           symdef = this->get_sized_symbol<size>(pdef->second);
 876           Symbol_table::resolve<size, big_endian>(sym, symdef);
 877           this->make_forwarder(pdef->second, sym);
 878           pdef->second = sym;
 879           sym->set_is_default();
 880         }
 881     }
 882 }
 883
 884 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
 885 // name and VERSION is the version; both are canonicalized.  DEF is
 886 // whether this is the default version.  ST_SHNDX is the symbol's
 887 // section index; IS_ORDINARY is whether this is a normal section
 888 // rather than a special code.
 889
 890 // If IS_DEFAULT_VERSION is true, then this is the definition of a
 891 // default version of a symbol.  That means that any lookup of
 892 // NAME/NULL and any lookup of NAME/VERSION should always return the
 893 // same symbol.  This is obvious for references, but in particular we
 894 // want to do this for definitions: overriding NAME/NULL should also
 895 // override NAME/VERSION.  If we don't do that, it would be very hard
 896 // to override functions in a shared library which uses versioning.
 897
 898 // We implement this by simply making both entries in the hash table
 899 // point to the same Symbol structure.  That is easy enough if this is
 900 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
 901 // that we have seen both already, in which case they will both have
 902 // independent entries in the symbol table.  We can't simply change
 903 // the symbol table entry, because we have pointers to the entries
 904 // attached to the object files.  So we mark the entry attached to the
 905 // object file as a forwarder, and record it in the forwarders_ map.
 906 // Note that entries in the hash table will never be marked as
 907 // forwarders.
 908 //
 909 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
 910 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
 911 // for a special section code.  ST_SHNDX may be modified if the symbol
 912 // is defined in a section being discarded.
 913
 914 template<int size, bool big_endian>
 915 Sized_symbol<size>*
 916 Symbol_table::add_from_object(Object* object,
 917                               const char* name,
 918                               Stringpool::Key name_key,
 919                               const char* version,
 920                               Stringpool::Key version_key,
 921                               bool is_default_version,
 922                               const elfcpp::Sym<size, big_endian>& sym,
 923                               unsigned int st_shndx,
 924                               bool is_ordinary,
 925                               unsigned int orig_st_shndx)
 926 {
 927   // Print a message if this symbol is being traced.
 928   if (parameters->options().is_trace_symbol(name))
 929     {
 930       if (orig_st_shndx == elfcpp::SHN_UNDEF)
 931         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
 932       else
 933         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
 934     }
 935
 936   // For an undefined symbol, we may need to adjust the name using
 937   // --wrap.
 938   if (orig_st_shndx == elfcpp::SHN_UNDEF
 939       && parameters->options().any_wrap())
 940     {
 941       const char* wrap_name = this->wrap_symbol(name, &name_key);
 942       if (wrap_name != name)
 943         {
 944           // If we see a reference to malloc with version GLIBC_2.0,
 945           // and we turn it into a reference to __wrap_malloc, then we
 946           // discard the version number.  Otherwise the user would be
 947           // required to specify the correct version for
 948           // __wrap_malloc.
 949           version = NULL;
 950           version_key = 0;
 951           name = wrap_name;
 952         }
 953     }
 954
 955   Symbol* const snull = NULL;
 956   std::pair<typename Symbol_table_type::iterator, bool> ins =
 957     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
 958                                        snull));
 959
 960   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
 961     std::make_pair(this->table_.end(), false);
 962   if (is_default_version)
 963     {
 964       const Stringpool::Key vnull_key = 0;
 965       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
 966                                                                      vnull_key),
 967                                                       snull));
 968     }
 969
 970   // ins.first: an iterator, which is a pointer to a pair.
 971   // ins.first->first: the key (a pair of name and version).
 972   // ins.first->second: the value (Symbol*).
 973   // ins.second: true if new entry was inserted, false if not.
 974
 975   Sized_symbol<size>* ret;
 976   bool was_undefined;
 977   bool was_common;
 978   if (!ins.second)
 979     {
 980       // We already have an entry for NAME/VERSION.
 981       ret = this->get_sized_symbol<size>(ins.first->second);
 982       gold_assert(ret != NULL);
 983
 984       was_undefined = ret->is_undefined();
 985       // Commons from plugins are just placeholders.
 986       was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
 987
 988       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
 989                     version);
 990       if (parameters->options().gc_sections())
 991         this->gc_mark_dyn_syms(ret);
 992
 993       if (is_default_version)
 994         this->define_default_version<size, big_endian>(ret, insdefault.second,
 995                                                        insdefault.first);
 996     }
 997   else
 998     {
 999       // This is the first time we have seen NAME/VERSION.
1000       gold_assert(ins.first->second == NULL);
1001
1002       if (is_default_version && !insdefault.second)
1003         {
1004           // We already have an entry for NAME/NULL.  If we override
1005           // it, then change it to NAME/VERSION.
1006           ret = this->get_sized_symbol<size>(insdefault.first->second);
1007
1008           was_undefined = ret->is_undefined();
1009           // Commons from plugins are just placeholders.
1010           was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
1011
1012           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
1013                         version);
1014           if (parameters->options().gc_sections())
1015             this->gc_mark_dyn_syms(ret);
1016           ins.first->second = ret;
1017         }
1018       else
1019         {
1020           was_undefined = false;
1021           was_common = false;
1022
1023           Sized_target<size, big_endian>* target =
1024             parameters->sized_target<size, big_endian>();
1025           if (!target->has_make_symbol())
1026             ret = new Sized_symbol<size>();
1027           else
1028             {
1029               ret = target->make_symbol();
1030               if (ret == NULL)
1031                 {
1032                   // This means that we don't want a symbol table
1033                   // entry after all.
1034                   if (!is_default_version)
1035                     this->table_.erase(ins.first);
1036                   else
1037                     {
1038                       this->table_.erase(insdefault.first);
1039                       // Inserting INSDEFAULT invalidated INS.
1040                       this->table_.erase(std::make_pair(name_key,
1041                                                         version_key));
1042                     }
1043                   return NULL;
1044                 }
1045             }
1046
1047           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
1048
1049           ins.first->second = ret;
1050           if (is_default_version)
1051             {
1052               // This is the first time we have seen NAME/NULL.  Point
1053               // it at the new entry for NAME/VERSION.
1054               gold_assert(insdefault.second);
1055               insdefault.first->second = ret;
1056             }
1057         }
1058
1059       if (is_default_version)
1060         ret->set_is_default();
1061     }
1062
1063   // Record every time we see a new undefined symbol, to speed up
1064   // archive groups.
1065   if (!was_undefined && ret->is_undefined())
1066     {
1067       ++this->saw_undefined_;
1068       if (parameters->options().has_plugins())
1069         parameters->options().plugins()->new_undefined_symbol(ret);
1070     }
1071
1072   // Keep track of common symbols, to speed up common symbol
1073   // allocation.  Don't record commons from plugin objects;
1074   // we need to wait until we see the real symbol in the
1075   // replacement file.
1076   if (!was_common && ret->is_common() && ret->object()->pluginobj() == NULL)
1077     {
1078       if (ret->type() == elfcpp::STT_TLS)
1079         this->tls_commons_.push_back(ret);
1080       else if (!is_ordinary
1081                && st_shndx == parameters->target().small_common_shndx())
1082         this->small_commons_.push_back(ret);
1083       else if (!is_ordinary
1084                && st_shndx == parameters->target().large_common_shndx())
1085         this->large_commons_.push_back(ret);
1086       else
1087         this->commons_.push_back(ret);
1088     }
1089
1090   // If we're not doing a relocatable link, then any symbol with
1091   // hidden or internal visibility is local.
1092   if ((ret->visibility() == elfcpp::STV_HIDDEN
1093        || ret->visibility() == elfcpp::STV_INTERNAL)
1094       && (ret->binding() == elfcpp::STB_GLOBAL
1095           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1096           || ret->binding() == elfcpp::STB_WEAK)
1097       && !parameters->options().relocatable())
1098     this->force_local(ret);
1099
1100   return ret;
1101 }
1102
1103 // Add all the symbols in a relocatable object to the hash table.
1104
1105 template<int size, bool big_endian>
1106 void
1107 Symbol_table::add_from_relobj(
1108     Sized_relobj_file<size, big_endian>* relobj,
1109     const unsigned char* syms,
1110     size_t count,
1111     size_t symndx_offset,
1112     const char* sym_names,
1113     size_t sym_name_size,
1114     typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
1115     size_t* defined)
1116 {
1117   *defined = 0;
1118
1119   gold_assert(size == parameters->target().get_size());
1120
1121   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1122
1123   const bool just_symbols = relobj->just_symbols();
1124
1125   const unsigned char* p = syms;
1126   for (size_t i = 0; i < count; ++i, p += sym_size)
1127     {
1128       (*sympointers)[i] = NULL;
1129
1130       elfcpp::Sym<size, big_endian> sym(p);
1131
1132       unsigned int st_name = sym.get_st_name();
1133       if (st_name >= sym_name_size)
1134         {
1135           relobj->error(_("bad global symbol name offset %u at %zu"),
1136                         st_name, i);
1137           continue;
1138         }
1139
1140       const char* name = sym_names + st_name;
1141
1142       if (strcmp (name, "__gnu_lto_slim") == 0)
1143         gold_info(_("%s: plugin needed to handle lto object"),
1144                   relobj->name().c_str());
1145
1146       bool is_ordinary;
1147       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1148                                                        sym.get_st_shndx(),
1149                                                        &is_ordinary);
1150       unsigned int orig_st_shndx = st_shndx;
1151       if (!is_ordinary)
1152         orig_st_shndx = elfcpp::SHN_UNDEF;
1153
1154       if (st_shndx != elfcpp::SHN_UNDEF)
1155         ++*defined;
1156
1157       // A symbol defined in a section which we are not including must
1158       // be treated as an undefined symbol.
1159       bool is_defined_in_discarded_section = false;
1160       if (st_shndx != elfcpp::SHN_UNDEF
1161           && is_ordinary
1162           && !relobj->is_section_included(st_shndx)
1163           && !this->is_section_folded(relobj, st_shndx))
1164         {
1165           st_shndx = elfcpp::SHN_UNDEF;
1166           is_defined_in_discarded_section = true;
1167         }
1168
1169       // In an object file, an '@' in the name separates the symbol
1170       // name from the version name.  If there are two '@' characters,
1171       // this is the default version.
1172       const char* ver = strchr(name, '@');
1173       Stringpool::Key ver_key = 0;
1174       int namelen = 0;
1175       // IS_DEFAULT_VERSION: is the version default?
1176       // IS_FORCED_LOCAL: is the symbol forced local?
1177       bool is_default_version = false;
1178       bool is_forced_local = false;
1179
1180       // FIXME: For incremental links, we don't store version information,
1181       // so we need to ignore version symbols for now.
1182       if (parameters->incremental_update() && ver != NULL)
1183         {
1184           namelen = ver - name;
1185           ver = NULL;
1186         }
1187
1188       if (ver != NULL)
1189         {
1190           // The symbol name is of the form foo@VERSION or foo@@VERSION
1191           namelen = ver - name;
1192           ++ver;
1193           if (*ver == '@')
1194             {
1195               is_default_version = true;
1196               ++ver;
1197             }
1198           ver = this->namepool_.add(ver, true, &ver_key);
1199         }
1200       // We don't want to assign a version to an undefined symbol,
1201       // even if it is listed in the version script.  FIXME: What
1202       // about a common symbol?
1203       else
1204         {
1205           namelen = strlen(name);
1206           if (!this->version_script_.empty()
1207               && st_shndx != elfcpp::SHN_UNDEF)
1208             {
1209               // The symbol name did not have a version, but the
1210               // version script may assign a version anyway.
1211               std::string version;
1212               bool is_global;
1213               if (this->version_script_.get_symbol_version(name, &version,
1214                                                            &is_global))
1215                 {
1216                   if (!is_global)
1217                     is_forced_local = true;
1218                   else if (!version.empty())
1219                     {
1220                       ver = this->namepool_.add_with_length(version.c_str(),
1221                                                             version.length(),
1222                                                             true,
1223                                                             &ver_key);
1224                       is_default_version = true;
1225                     }
1226                 }
1227             }
1228         }
1229
1230       elfcpp::Sym<size, big_endian>* psym = &sym;
1231       unsigned char symbuf[sym_size];
1232       elfcpp::Sym<size, big_endian> sym2(symbuf);
1233       if (just_symbols)
1234         {
1235           memcpy(symbuf, p, sym_size);
1236           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1237           if (orig_st_shndx != elfcpp::SHN_UNDEF
1238               && is_ordinary
1239               && relobj->e_type() == elfcpp::ET_REL)
1240             {
1241               // Symbol values in relocatable object files are section
1242               // relative.  This is normally what we want, but since here
1243               // we are converting the symbol to absolute we need to add
1244               // the section address.  The section address in an object
1245               // file is normally zero, but people can use a linker
1246               // script to change it.
1247               sw.put_st_value(sym.get_st_value()
1248                               + relobj->section_address(orig_st_shndx));
1249             }
1250           st_shndx = elfcpp::SHN_ABS;
1251           is_ordinary = false;
1252           psym = &sym2;
1253         }
1254
1255       // Fix up visibility if object has no-export set.
1256       if (relobj->no_export()
1257           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1258         {
1259           // We may have copied symbol already above.
1260           if (psym != &sym2)
1261             {
1262               memcpy(symbuf, p, sym_size);
1263               psym = &sym2;
1264             }
1265
1266           elfcpp::STV visibility = sym2.get_st_visibility();
1267           if (visibility == elfcpp::STV_DEFAULT
1268               || visibility == elfcpp::STV_PROTECTED)
1269             {
1270               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1271               unsigned char nonvis = sym2.get_st_nonvis();
1272               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1273             }
1274         }
1275
1276       Stringpool::Key name_key;
1277       name = this->namepool_.add_with_length(name, namelen, true,
1278                                              &name_key);
1279
1280       Sized_symbol<size>* res;
1281       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1282                                   is_default_version, *psym, st_shndx,
1283                                   is_ordinary, orig_st_shndx);
1284
1285       if (is_forced_local)
1286         this->force_local(res);
1287
1288       // Do not treat this symbol as garbage if this symbol will be
1289       // exported to the dynamic symbol table.  This is true when
1290       // building a shared library or using --export-dynamic and
1291       // the symbol is externally visible.
1292       if (parameters->options().gc_sections()
1293           && res->is_externally_visible()
1294           && !res->is_from_dynobj()
1295           && (parameters->options().shared()
1296               || parameters->options().export_dynamic()
1297               || parameters->options().in_dynamic_list(res->name())))
1298         this->gc_mark_symbol(res);
1299
1300       if (is_defined_in_discarded_section)
1301         res->set_is_defined_in_discarded_section();
1302
1303       (*sympointers)[i] = res;
1304     }
1305 }
1306
1307 // Add a symbol from a plugin-claimed file.
1308
1309 template<int size, bool big_endian>
1310 Symbol*
1311 Symbol_table::add_from_pluginobj(
1312     Sized_pluginobj<size, big_endian>* obj,
1313     const char* name,
1314     const char* ver,
1315     elfcpp::Sym<size, big_endian>* sym)
1316 {
1317   unsigned int st_shndx = sym->get_st_shndx();
1318   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1319
1320   Stringpool::Key ver_key = 0;
1321   bool is_default_version = false;
1322   bool is_forced_local = false;
1323
1324   if (ver != NULL)
1325     {
1326       ver = this->namepool_.add(ver, true, &ver_key);
1327     }
1328   // We don't want to assign a version to an undefined symbol,
1329   // even if it is listed in the version script.  FIXME: What
1330   // about a common symbol?
1331   else
1332     {
1333       if (!this->version_script_.empty()
1334           && st_shndx != elfcpp::SHN_UNDEF)
1335         {
1336           // The symbol name did not have a version, but the
1337           // version script may assign a version anyway.
1338           std::string version;
1339           bool is_global;
1340           if (this->version_script_.get_symbol_version(name, &version,
1341                                                        &is_global))
1342             {
1343               if (!is_global)
1344                 is_forced_local = true;
1345               else if (!version.empty())
1346                 {
1347                   ver = this->namepool_.add_with_length(version.c_str(),
1348                                                         version.length(),
1349                                                         true,
1350                                                         &ver_key);
1351                   is_default_version = true;
1352                 }
1353             }
1354         }
1355     }
1356
1357   Stringpool::Key name_key;
1358   name = this->namepool_.add(name, true, &name_key);
1359
1360   Sized_symbol<size>* res;
1361   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1362                               is_default_version, *sym, st_shndx,
1363                               is_ordinary, st_shndx);
1364
1365   if (is_forced_local)
1366     this->force_local(res);
1367
1368   return res;
1369 }
1370
1371 // Add all the symbols in a dynamic object to the hash table.
1372
1373 template<int size, bool big_endian>
1374 void
1375 Symbol_table::add_from_dynobj(
1376     Sized_dynobj<size, big_endian>* dynobj,
1377     const unsigned char* syms,
1378     size_t count,
1379     const char* sym_names,
1380     size_t sym_name_size,
1381     const unsigned char* versym,
1382     size_t versym_size,
1383     const std::vector<const char*>* version_map,
1384     typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
1385     size_t* defined)
1386 {
1387   *defined = 0;
1388
1389   gold_assert(size == parameters->target().get_size());
1390
1391   if (dynobj->just_symbols())
1392     {
1393       gold_error(_("--just-symbols does not make sense with a shared object"));
1394       return;
1395     }
1396
1397   // FIXME: For incremental links, we don't store version information,
1398   // so we need to ignore version symbols for now.
1399   if (parameters->incremental_update())
1400     versym = NULL;
1401
1402   if (versym != NULL && versym_size / 2 < count)
1403     {
1404       dynobj->error(_("too few symbol versions"));
1405       return;
1406     }
1407
1408   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1409
1410   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1411   // weak aliases.  This is necessary because if the dynamic object
1412   // provides the same variable under two names, one of which is a
1413   // weak definition, and the regular object refers to the weak
1414   // definition, we have to put both the weak definition and the
1415   // strong definition into the dynamic symbol table.  Given a weak
1416   // definition, the only way that we can find the corresponding
1417   // strong definition, if any, is to search the symbol table.
1418   std::vector<Sized_symbol<size>*> object_symbols;
1419
1420   const unsigned char* p = syms;
1421   const unsigned char* vs = versym;
1422   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1423     {
1424       elfcpp::Sym<size, big_endian> sym(p);
1425
1426       if (sympointers != NULL)
1427         (*sympointers)[i] = NULL;
1428
1429       // Ignore symbols with local binding or that have
1430       // internal or hidden visibility.
1431       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1432           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1433           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1434         continue;
1435
1436       // A protected symbol in a shared library must be treated as a
1437       // normal symbol when viewed from outside the shared library.
1438       // Implement this by overriding the visibility here.
1439       elfcpp::Sym<size, big_endian>* psym = &sym;
1440       unsigned char symbuf[sym_size];
1441       elfcpp::Sym<size, big_endian> sym2(symbuf);
1442       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1443         {
1444           memcpy(symbuf, p, sym_size);
1445           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1446           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1447           psym = &sym2;
1448         }
1449
1450       unsigned int st_name = psym->get_st_name();
1451       if (st_name >= sym_name_size)
1452         {
1453           dynobj->error(_("bad symbol name offset %u at %zu"),
1454                         st_name, i);
1455           continue;
1456         }
1457
1458       const char* name = sym_names + st_name;
1459
1460       bool is_ordinary;
1461       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1462                                                        &is_ordinary);
1463
1464       if (st_shndx != elfcpp::SHN_UNDEF)
1465         ++*defined;
1466
1467       Sized_symbol<size>* res;
1468
1469       if (versym == NULL)
1470         {
1471           Stringpool::Key name_key;
1472           name = this->namepool_.add(name, true, &name_key);
1473           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1474                                       false, *psym, st_shndx, is_ordinary,
1475                                       st_shndx);
1476         }
1477       else
1478         {
1479           // Read the version information.
1480
1481           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1482
1483           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1484           v &= elfcpp::VERSYM_VERSION;
1485
1486           // The Sun documentation says that V can be VER_NDX_LOCAL,
1487           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1488           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1489           // The old GNU linker will happily generate VER_NDX_LOCAL
1490           // for an undefined symbol.  I don't know what the Sun
1491           // linker will generate.
1492
1493           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1494               && st_shndx != elfcpp::SHN_UNDEF)
1495             {
1496               // This symbol should not be visible outside the object.
1497               continue;
1498             }
1499
1500           // At this point we are definitely going to add this symbol.
1501           Stringpool::Key name_key;
1502           name = this->namepool_.add(name, true, &name_key);
1503
1504           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1505               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1506             {
1507               // This symbol does not have a version.
1508               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1509                                           false, *psym, st_shndx, is_ordinary,
1510                                           st_shndx);
1511             }
1512           else
1513             {
1514               if (v >= version_map->size())
1515                 {
1516                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1517                                 i, v);
1518                   continue;
1519                 }
1520
1521               const char* version = (*version_map)[v];
1522               if (version == NULL)
1523                 {
1524                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1525                                 i, v);
1526                   continue;
1527                 }
1528
1529               Stringpool::Key version_key;
1530               version = this->namepool_.add(version, true, &version_key);
1531
1532               // If this is an absolute symbol, and the version name
1533               // and symbol name are the same, then this is the
1534               // version definition symbol.  These symbols exist to
1535               // support using -u to pull in particular versions.  We
1536               // do not want to record a version for them.
1537               if (st_shndx == elfcpp::SHN_ABS
1538                   && !is_ordinary
1539                   && name_key == version_key)
1540                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1541                                             false, *psym, st_shndx, is_ordinary,
1542                                             st_shndx);
1543               else
1544                 {
1545                   const bool is_default_version =
1546                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1547                   res = this->add_from_object(dynobj, name, name_key, version,
1548                                               version_key, is_default_version,
1549                                               *psym, st_shndx,
1550                                               is_ordinary, st_shndx);
1551                 }
1552             }
1553         }
1554
1555       // Note that it is possible that RES was overridden by an
1556       // earlier object, in which case it can't be aliased here.
1557       if (st_shndx != elfcpp::SHN_UNDEF
1558           && is_ordinary
1559           && psym->get_st_type() == elfcpp::STT_OBJECT
1560           && res->source() == Symbol::FROM_OBJECT
1561           && res->object() == dynobj)
1562         object_symbols.push_back(res);
1563
1564       if (sympointers != NULL)
1565         (*sympointers)[i] = res;
1566     }
1567
1568   this->record_weak_aliases(&object_symbols);
1569 }
1570
1571 // Add a symbol from a incremental object file.
1572
1573 template<int size, bool big_endian>
1574 Sized_symbol<size>*
1575 Symbol_table::add_from_incrobj(
1576     Object* obj,
1577     const char* name,
1578     const char* ver,
1579     elfcpp::Sym<size, big_endian>* sym)
1580 {
1581   unsigned int st_shndx = sym->get_st_shndx();
1582   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1583
1584   Stringpool::Key ver_key = 0;
1585   bool is_default_version = false;
1586   bool is_forced_local = false;
1587
1588   Stringpool::Key name_key;
1589   name = this->namepool_.add(name, true, &name_key);
1590
1591   Sized_symbol<size>* res;
1592   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1593                               is_default_version, *sym, st_shndx,
1594                               is_ordinary, st_shndx);
1595
1596   if (is_forced_local)
1597     this->force_local(res);
1598
1599   return res;
1600 }
1601
1602 // This is used to sort weak aliases.  We sort them first by section
1603 // index, then by offset, then by weak ahead of strong.
1604
1605 template<int size>
1606 class Weak_alias_sorter
1607 {
1608  public:
1609   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1610 };
1611
1612 template<int size>
1613 bool
1614 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1615                                     const Sized_symbol<size>* s2) const
1616 {
1617   bool is_ordinary;
1618   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1619   gold_assert(is_ordinary);
1620   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1621   gold_assert(is_ordinary);
1622   if (s1_shndx != s2_shndx)
1623     return s1_shndx < s2_shndx;
1624
1625   if (s1->value() != s2->value())
1626     return s1->value() < s2->value();
1627   if (s1->binding() != s2->binding())
1628     {
1629       if (s1->binding() == elfcpp::STB_WEAK)
1630         return true;
1631       if (s2->binding() == elfcpp::STB_WEAK)
1632         return false;
1633     }
1634   return std::string(s1->name()) < std::string(s2->name());
1635 }
1636
1637 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1638 // for any weak aliases, and record them so that if we add the weak
1639 // alias to the dynamic symbol table, we also add the corresponding
1640 // strong symbol.
1641
1642 template<int size>
1643 void
1644 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1645 {
1646   // Sort the vector by section index, then by offset, then by weak
1647   // ahead of strong.
1648   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1649
1650   // Walk through the vector.  For each weak definition, record
1651   // aliases.
1652   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1653          symbols->begin();
1654        p != symbols->end();
1655        ++p)
1656     {
1657       if ((*p)->binding() != elfcpp::STB_WEAK)
1658         continue;
1659
1660       // Build a circular list of weak aliases.  Each symbol points to
1661       // the next one in the circular list.
1662
1663       Sized_symbol<size>* from_sym = *p;
1664       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1665       for (q = p + 1; q != symbols->end(); ++q)
1666         {
1667           bool dummy;
1668           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1669               || (*q)->value() != from_sym->value())
1670             break;
1671
1672           this->weak_aliases_[from_sym] = *q;
1673           from_sym->set_has_alias();
1674           from_sym = *q;
1675         }
1676
1677       if (from_sym != *p)
1678         {
1679           this->weak_aliases_[from_sym] = *p;
1680           from_sym->set_has_alias();
1681         }
1682
1683       p = q - 1;
1684     }
1685 }
1686
1687 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1688 // true, then only create the symbol if there is a reference to it.
1689 // If this does not return NULL, it sets *POLDSYM to the existing
1690 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1691 // resolve the newly created symbol to the old one.  This
1692 // canonicalizes *PNAME and *PVERSION.
1693
1694 template<int size, bool big_endian>
1695 Sized_symbol<size>*
1696 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1697                                     bool only_if_ref,
1698                                     Sized_symbol<size>** poldsym,
1699                                     bool* resolve_oldsym)
1700 {
1701   *resolve_oldsym = false;
1702   *poldsym = NULL;
1703
1704   // If the caller didn't give us a version, see if we get one from
1705   // the version script.
1706   std::string v;
1707   bool is_default_version = false;
1708   if (*pversion == NULL)
1709     {
1710       bool is_global;
1711       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1712         {
1713           if (is_global && !v.empty())
1714             {
1715               *pversion = v.c_str();
1716               // If we get the version from a version script, then we
1717               // are also the default version.
1718               is_default_version = true;
1719             }
1720         }
1721     }
1722
1723   Symbol* oldsym;
1724   Sized_symbol<size>* sym;
1725
1726   bool add_to_table = false;
1727   typename Symbol_table_type::iterator add_loc = this->table_.end();
1728   bool add_def_to_table = false;
1729   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1730
1731   if (only_if_ref)
1732     {
1733       oldsym = this->lookup(*pname, *pversion);
1734       if (oldsym == NULL && is_default_version)
1735         oldsym = this->lookup(*pname, NULL);
1736       if (oldsym == NULL || !oldsym->is_undefined())
1737         return NULL;
1738
1739       *pname = oldsym->name();
1740       if (is_default_version)
1741         *pversion = this->namepool_.add(*pversion, true, NULL);
1742       else
1743         *pversion = oldsym->version();
1744     }
1745   else
1746     {
1747       // Canonicalize NAME and VERSION.
1748       Stringpool::Key name_key;
1749       *pname = this->namepool_.add(*pname, true, &name_key);
1750
1751       Stringpool::Key version_key = 0;
1752       if (*pversion != NULL)
1753         *pversion = this->namepool_.add(*pversion, true, &version_key);
1754
1755       Symbol* const snull = NULL;
1756       std::pair<typename Symbol_table_type::iterator, bool> ins =
1757         this->table_.insert(std::make_pair(std::make_pair(name_key,
1758                                                           version_key),
1759                                            snull));
1760
1761       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1762         std::make_pair(this->table_.end(), false);
1763       if (is_default_version)
1764         {
1765           const Stringpool::Key vnull = 0;
1766           insdefault =
1767             this->table_.insert(std::make_pair(std::make_pair(name_key,
1768                                                               vnull),
1769                                                snull));
1770         }
1771
1772       if (!ins.second)
1773         {
1774           // We already have a symbol table entry for NAME/VERSION.
1775           oldsym = ins.first->second;
1776           gold_assert(oldsym != NULL);
1777
1778           if (is_default_version)
1779             {
1780               Sized_symbol<size>* soldsym =
1781                 this->get_sized_symbol<size>(oldsym);
1782               this->define_default_version<size, big_endian>(soldsym,
1783                                                              insdefault.second,
1784                                                              insdefault.first);
1785             }
1786         }
1787       else
1788         {
1789           // We haven't seen this symbol before.
1790           gold_assert(ins.first->second == NULL);
1791
1792           add_to_table = true;
1793           add_loc = ins.first;
1794
1795           if (is_default_version && !insdefault.second)
1796             {
1797               // We are adding NAME/VERSION, and it is the default
1798               // version.  We already have an entry for NAME/NULL.
1799               oldsym = insdefault.first->second;
1800               *resolve_oldsym = true;
1801             }
1802           else
1803             {
1804               oldsym = NULL;
1805
1806               if (is_default_version)
1807                 {
1808                   add_def_to_table = true;
1809                   add_def_loc = insdefault.first;
1810                 }
1811             }
1812         }
1813     }
1814
1815   const Target& target = parameters->target();
1816   if (!target.has_make_symbol())
1817     sym = new Sized_symbol<size>();
1818   else
1819     {
1820       Sized_target<size, big_endian>* sized_target =
1821         parameters->sized_target<size, big_endian>();
1822       sym = sized_target->make_symbol();
1823       if (sym == NULL)
1824         return NULL;
1825     }
1826
1827   if (add_to_table)
1828     add_loc->second = sym;
1829   else
1830     gold_assert(oldsym != NULL);
1831
1832   if (add_def_to_table)
1833     add_def_loc->second = sym;
1834
1835   *poldsym = this->get_sized_symbol<size>(oldsym);
1836
1837   return sym;
1838 }
1839
1840 // Define a symbol based on an Output_data.
1841
1842 Symbol*
1843 Symbol_table::define_in_output_data(const char* name,
1844                                     const char* version,
1845                                     Defined defined,
1846                                     Output_data* od,
1847                                     uint64_t value,
1848                                     uint64_t symsize,
1849                                     elfcpp::STT type,
1850                                     elfcpp::STB binding,
1851                                     elfcpp::STV visibility,
1852                                     unsigned char nonvis,
1853                                     bool offset_is_from_end,
1854                                     bool only_if_ref)
1855 {
1856   if (parameters->target().get_size() == 32)
1857     {
1858 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1859       return this->do_define_in_output_data<32>(name, version, defined, od,
1860                                                 value, symsize, type, binding,
1861                                                 visibility, nonvis,
1862                                                 offset_is_from_end,
1863                                                 only_if_ref);
1864 #else
1865       gold_unreachable();
1866 #endif
1867     }
1868   else if (parameters->target().get_size() == 64)
1869     {
1870 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1871       return this->do_define_in_output_data<64>(name, version, defined, od,
1872                                                 value, symsize, type, binding,
1873                                                 visibility, nonvis,
1874                                                 offset_is_from_end,
1875                                                 only_if_ref);
1876 #else
1877       gold_unreachable();
1878 #endif
1879     }
1880   else
1881     gold_unreachable();
1882 }
1883
1884 // Define a symbol in an Output_data, sized version.
1885
1886 template<int size>
1887 Sized_symbol<size>*
1888 Symbol_table::do_define_in_output_data(
1889     const char* name,
1890     const char* version,
1891     Defined defined,
1892     Output_data* od,
1893     typename elfcpp::Elf_types<size>::Elf_Addr value,
1894     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1895     elfcpp::STT type,
1896     elfcpp::STB binding,
1897     elfcpp::STV visibility,
1898     unsigned char nonvis,
1899     bool offset_is_from_end,
1900     bool only_if_ref)
1901 {
1902   Sized_symbol<size>* sym;
1903   Sized_symbol<size>* oldsym;
1904   bool resolve_oldsym;
1905
1906   if (parameters->target().is_big_endian())
1907     {
1908 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1909       sym = this->define_special_symbol<size, true>(&name, &version,
1910                                                     only_if_ref, &oldsym,
1911                                                     &resolve_oldsym);
1912 #else
1913       gold_unreachable();
1914 #endif
1915     }
1916   else
1917     {
1918 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1919       sym = this->define_special_symbol<size, false>(&name, &version,
1920                                                      only_if_ref, &oldsym,
1921                                                      &resolve_oldsym);
1922 #else
1923       gold_unreachable();
1924 #endif
1925     }
1926
1927   if (sym == NULL)
1928     return NULL;
1929
1930   sym->init_output_data(name, version, od, value, symsize, type, binding,
1931                         visibility, nonvis, offset_is_from_end,
1932                         defined == PREDEFINED);
1933
1934   if (oldsym == NULL)
1935     {
1936       if (binding == elfcpp::STB_LOCAL
1937           || this->version_script_.symbol_is_local(name))
1938         this->force_local(sym);
1939       else if (version != NULL)
1940         sym->set_is_default();
1941       return sym;
1942     }
1943
1944   if (Symbol_table::should_override_with_special(oldsym, type, defined))
1945     this->override_with_special(oldsym, sym);
1946
1947   if (resolve_oldsym)
1948     return sym;
1949   else
1950     {
1951       delete sym;
1952       return oldsym;
1953     }
1954 }
1955
1956 // Define a symbol based on an Output_segment.
1957
1958 Symbol*
1959 Symbol_table::define_in_output_segment(const char* name,
1960                                        const char* version,
1961                                        Defined defined,
1962                                        Output_segment* os,
1963                                        uint64_t value,
1964                                        uint64_t symsize,
1965                                        elfcpp::STT type,
1966                                        elfcpp::STB binding,
1967                                        elfcpp::STV visibility,
1968                                        unsigned char nonvis,
1969                                        Symbol::Segment_offset_base offset_base,
1970                                        bool only_if_ref)
1971 {
1972   if (parameters->target().get_size() == 32)
1973     {
1974 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1975       return this->do_define_in_output_segment<32>(name, version, defined, os,
1976                                                    value, symsize, type,
1977                                                    binding, visibility, nonvis,
1978                                                    offset_base, only_if_ref);
1979 #else
1980       gold_unreachable();
1981 #endif
1982     }
1983   else if (parameters->target().get_size() == 64)
1984     {
1985 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1986       return this->do_define_in_output_segment<64>(name, version, defined, os,
1987                                                    value, symsize, type,
1988                                                    binding, visibility, nonvis,
1989                                                    offset_base, only_if_ref);
1990 #else
1991       gold_unreachable();
1992 #endif
1993     }
1994   else
1995     gold_unreachable();
1996 }
1997
1998 // Define a symbol in an Output_segment, sized version.
1999
2000 template<int size>
2001 Sized_symbol<size>*
2002 Symbol_table::do_define_in_output_segment(
2003     const char* name,
2004     const char* version,
2005     Defined defined,
2006     Output_segment* os,
2007     typename elfcpp::Elf_types<size>::Elf_Addr value,
2008     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
2009     elfcpp::STT type,
2010     elfcpp::STB binding,
2011     elfcpp::STV visibility,
2012     unsigned char nonvis,
2013     Symbol::Segment_offset_base offset_base,
2014     bool only_if_ref)
2015 {
2016   Sized_symbol<size>* sym;
2017   Sized_symbol<size>* oldsym;
2018   bool resolve_oldsym;
2019
2020   if (parameters->target().is_big_endian())
2021     {
2022 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2023       sym = this->define_special_symbol<size, true>(&name, &version,
2024                                                     only_if_ref, &oldsym,
2025                                                     &resolve_oldsym);
2026 #else
2027       gold_unreachable();
2028 #endif
2029     }
2030   else
2031     {
2032 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2033       sym = this->define_special_symbol<size, false>(&name, &version,
2034                                                      only_if_ref, &oldsym,
2035                                                      &resolve_oldsym);
2036 #else
2037       gold_unreachable();
2038 #endif
2039     }
2040
2041   if (sym == NULL)
2042     return NULL;
2043
2044   sym->init_output_segment(name, version, os, value, symsize, type, binding,
2045                            visibility, nonvis, offset_base,
2046                            defined == PREDEFINED);
2047
2048   if (oldsym == NULL)
2049     {
2050       if (binding == elfcpp::STB_LOCAL
2051           || this->version_script_.symbol_is_local(name))
2052         this->force_local(sym);
2053       else if (version != NULL)
2054         sym->set_is_default();
2055       return sym;
2056     }
2057
2058   if (Symbol_table::should_override_with_special(oldsym, type, defined))
2059     this->override_with_special(oldsym, sym);
2060
2061   if (resolve_oldsym)
2062     return sym;
2063   else
2064     {
2065       delete sym;
2066       return oldsym;
2067     }
2068 }
2069
2070 // Define a special symbol with a constant value.  It is a multiple
2071 // definition error if this symbol is already defined.
2072
2073 Symbol*
2074 Symbol_table::define_as_constant(const char* name,
2075                                  const char* version,
2076                                  Defined defined,
2077                                  uint64_t value,
2078                                  uint64_t symsize,
2079                                  elfcpp::STT type,
2080                                  elfcpp::STB binding,
2081                                  elfcpp::STV visibility,
2082                                  unsigned char nonvis,
2083                                  bool only_if_ref,
2084                                  bool force_override)
2085 {
2086   if (parameters->target().get_size() == 32)
2087     {
2088 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2089       return this->do_define_as_constant<32>(name, version, defined, value,
2090                                              symsize, type, binding,
2091                                              visibility, nonvis, only_if_ref,
2092                                              force_override);
2093 #else
2094       gold_unreachable();
2095 #endif
2096     }
2097   else if (parameters->target().get_size() == 64)
2098     {
2099 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2100       return this->do_define_as_constant<64>(name, version, defined, value,
2101                                              symsize, type, binding,
2102                                              visibility, nonvis, only_if_ref,
2103                                              force_override);
2104 #else
2105       gold_unreachable();
2106 #endif
2107     }
2108   else
2109     gold_unreachable();
2110 }
2111
2112 // Define a symbol as a constant, sized version.
2113
2114 template<int size>
2115 Sized_symbol<size>*
2116 Symbol_table::do_define_as_constant(
2117     const char* name,
2118     const char* version,
2119     Defined defined,
2120     typename elfcpp::Elf_types<size>::Elf_Addr value,
2121     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
2122     elfcpp::STT type,
2123     elfcpp::STB binding,
2124     elfcpp::STV visibility,
2125     unsigned char nonvis,
2126     bool only_if_ref,
2127     bool force_override)
2128 {
2129   Sized_symbol<size>* sym;
2130   Sized_symbol<size>* oldsym;
2131   bool resolve_oldsym;
2132
2133   if (parameters->target().is_big_endian())
2134     {
2135 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2136       sym = this->define_special_symbol<size, true>(&name, &version,
2137                                                     only_if_ref, &oldsym,
2138                                                     &resolve_oldsym);
2139 #else
2140       gold_unreachable();
2141 #endif
2142     }
2143   else
2144     {
2145 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2146       sym = this->define_special_symbol<size, false>(&name, &version,
2147                                                      only_if_ref, &oldsym,
2148                                                      &resolve_oldsym);
2149 #else
2150       gold_unreachable();
2151 #endif
2152     }
2153
2154   if (sym == NULL)
2155     return NULL;
2156
2157   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2158                      nonvis, defined == PREDEFINED);
2159
2160   if (oldsym == NULL)
2161     {
2162       // Version symbols are absolute symbols with name == version.
2163       // We don't want to force them to be local.
2164       if ((version == NULL
2165            || name != version
2166            || value != 0)
2167           && (binding == elfcpp::STB_LOCAL
2168               || this->version_script_.symbol_is_local(name)))
2169         this->force_local(sym);
2170       else if (version != NULL
2171                && (name != version || value != 0))
2172         sym->set_is_default();
2173       return sym;
2174     }
2175
2176   if (force_override
2177       || Symbol_table::should_override_with_special(oldsym, type, defined))
2178     this->override_with_special(oldsym, sym);
2179
2180   if (resolve_oldsym)
2181     return sym;
2182   else
2183     {
2184       delete sym;
2185       return oldsym;
2186     }
2187 }
2188
2189 // Define a set of symbols in output sections.
2190
2191 void
2192 Symbol_table::define_symbols(const Layout* layout, int count,
2193                              const Define_symbol_in_section* p,
2194                              bool only_if_ref)
2195 {
2196   for (int i = 0; i < count; ++i, ++p)
2197     {
2198       Output_section* os = layout->find_output_section(p->output_section);
2199       if (os != NULL)
2200         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2201                                     p->size, p->type, p->binding,
2202                                     p->visibility, p->nonvis,
2203                                     p->offset_is_from_end,
2204                                     only_if_ref || p->only_if_ref);
2205       else
2206         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2207                                  p->type, p->binding, p->visibility, p->nonvis,
2208                                  only_if_ref || p->only_if_ref,
2209                                  false);
2210     }
2211 }
2212
2213 // Define a set of symbols in output segments.
2214
2215 void
2216 Symbol_table::define_symbols(const Layout* layout, int count,
2217                              const Define_symbol_in_segment* p,
2218                              bool only_if_ref)
2219 {
2220   for (int i = 0; i < count; ++i, ++p)
2221     {
2222       Output_segment* os = layout->find_output_segment(p->segment_type,
2223                                                        p->segment_flags_set,
2224                                                        p->segment_flags_clear);
2225       if (os != NULL)
2226         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2227                                        p->size, p->type, p->binding,
2228                                        p->visibility, p->nonvis,
2229                                        p->offset_base,
2230                                        only_if_ref || p->only_if_ref);
2231       else
2232         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2233                                  p->type, p->binding, p->visibility, p->nonvis,
2234                                  only_if_ref || p->only_if_ref,
2235                                  false);
2236     }
2237 }
2238
2239 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2240 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2241 // the offset within POSD.
2242
2243 template<int size>
2244 void
2245 Symbol_table::define_with_copy_reloc(
2246     Sized_symbol<size>* csym,
2247     Output_data* posd,
2248     typename elfcpp::Elf_types<size>::Elf_Addr value)
2249 {
2250   gold_assert(csym->is_from_dynobj());
2251   gold_assert(!csym->is_copied_from_dynobj());
2252   Object* object = csym->object();
2253   gold_assert(object->is_dynamic());
2254   Dynobj* dynobj = static_cast<Dynobj*>(object);
2255
2256   // Our copied variable has to override any variable in a shared
2257   // library.
2258   elfcpp::STB binding = csym->binding();
2259   if (binding == elfcpp::STB_WEAK)
2260     binding = elfcpp::STB_GLOBAL;
2261
2262   this->define_in_output_data(csym->name(), csym->version(), COPY,
2263                               posd, value, csym->symsize(),
2264                               csym->type(), binding,
2265                               csym->visibility(), csym->nonvis(),
2266                               false, false);
2267
2268   csym->set_is_copied_from_dynobj();
2269   csym->set_needs_dynsym_entry();
2270
2271   this->copied_symbol_dynobjs_[csym] = dynobj;
2272
2273   // We have now defined all aliases, but we have not entered them all
2274   // in the copied_symbol_dynobjs_ map.
2275   if (csym->has_alias())
2276     {
2277       Symbol* sym = csym;
2278       while (true)
2279         {
2280           sym = this->weak_aliases_[sym];
2281           if (sym == csym)
2282             break;
2283           gold_assert(sym->output_data() == posd);
2284
2285           sym->set_is_copied_from_dynobj();
2286           this->copied_symbol_dynobjs_[sym] = dynobj;
2287         }
2288     }
2289 }
2290
2291 // SYM is defined using a COPY reloc.  Return the dynamic object where
2292 // the original definition was found.
2293
2294 Dynobj*
2295 Symbol_table::get_copy_source(const Symbol* sym) const
2296 {
2297   gold_assert(sym->is_copied_from_dynobj());
2298   Copied_symbol_dynobjs::const_iterator p =
2299     this->copied_symbol_dynobjs_.find(sym);
2300   gold_assert(p != this->copied_symbol_dynobjs_.end());
2301   return p->second;
2302 }
2303
2304 // Add any undefined symbols named on the command line.
2305
2306 void
2307 Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
2308 {
2309   if (parameters->options().any_undefined()
2310       || layout->script_options()->any_unreferenced())
2311     {
2312       if (parameters->target().get_size() == 32)
2313         {
2314 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2315           this->do_add_undefined_symbols_from_command_line<32>(layout);
2316 #else
2317           gold_unreachable();
2318 #endif
2319         }
2320       else if (parameters->target().get_size() == 64)
2321         {
2322 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2323           this->do_add_undefined_symbols_from_command_line<64>(layout);
2324 #else
2325           gold_unreachable();
2326 #endif
2327         }
2328       else
2329         gold_unreachable();
2330     }
2331 }
2332
2333 template<int size>
2334 void
2335 Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
2336 {
2337   for (options::String_set::const_iterator p =
2338          parameters->options().undefined_begin();
2339        p != parameters->options().undefined_end();
2340        ++p)
2341     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2342
2343   for (options::String_set::const_iterator p =
2344          parameters->options().export_dynamic_symbol_begin();
2345        p != parameters->options().export_dynamic_symbol_end();
2346        ++p)
2347     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2348
2349   for (Script_options::referenced_const_iterator p =
2350          layout->script_options()->referenced_begin();
2351        p != layout->script_options()->referenced_end();
2352        ++p)
2353     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2354 }
2355
2356 template<int size>
2357 void
2358 Symbol_table::add_undefined_symbol_from_command_line(const char* name)
2359 {
2360   if (this->lookup(name) != NULL)
2361     return;
2362
2363   const char* version = NULL;
2364
2365   Sized_symbol<size>* sym;
2366   Sized_symbol<size>* oldsym;
2367   bool resolve_oldsym;
2368   if (parameters->target().is_big_endian())
2369     {
2370 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2371       sym = this->define_special_symbol<size, true>(&name, &version,
2372                                                     false, &oldsym,
2373                                                     &resolve_oldsym);
2374 #else
2375       gold_unreachable();
2376 #endif
2377     }
2378   else
2379     {
2380 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2381       sym = this->define_special_symbol<size, false>(&name, &version,
2382                                                      false, &oldsym,
2383                                                      &resolve_oldsym);
2384 #else
2385       gold_unreachable();
2386 #endif
2387     }
2388
2389   gold_assert(oldsym == NULL);
2390
2391   sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2392                       elfcpp::STV_DEFAULT, 0);
2393   ++this->saw_undefined_;
2394 }
2395
2396 // Set the dynamic symbol indexes.  INDEX is the index of the first
2397 // global dynamic symbol.  Pointers to the symbols are stored into the
2398 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2399 // updated dynamic symbol index.
2400
2401 unsigned int
2402 Symbol_table::set_dynsym_indexes(unsigned int index,
2403                                  std::vector<Symbol*>* syms,
2404                                  Stringpool* dynpool,
2405                                  Versions* versions)
2406 {
2407   std::vector<Symbol*> as_needed_sym;
2408
2409   // Allow a target to set dynsym indexes.
2410   if (parameters->target().has_custom_set_dynsym_indexes())
2411     {
2412       std::vector<Symbol*> dyn_symbols;
2413       for (Symbol_table_type::iterator p = this->table_.begin();
2414            p != this->table_.end();
2415            ++p)
2416         {
2417           Symbol* sym = p->second;
2418           if (!sym->should_add_dynsym_entry(this))
2419             sym->set_dynsym_index(-1U);
2420           else
2421             dyn_symbols.push_back(sym);
2422         }
2423
2424       return parameters->target().set_dynsym_indexes(&dyn_symbols, index, syms,
2425                                                      dynpool, versions, this);
2426     }
2427
2428   for (Symbol_table_type::iterator p = this->table_.begin();
2429        p != this->table_.end();
2430        ++p)
2431     {
2432       Symbol* sym = p->second;
2433
2434       // Note that SYM may already have a dynamic symbol index, since
2435       // some symbols appear more than once in the symbol table, with
2436       // and without a version.
2437
2438       if (!sym->should_add_dynsym_entry(this))
2439         sym->set_dynsym_index(-1U);
2440       else if (!sym->has_dynsym_index())
2441         {
2442           sym->set_dynsym_index(index);
2443           ++index;
2444           syms->push_back(sym);
2445           dynpool->add(sym->name(), false, NULL);
2446
2447           // If the symbol is defined in a dynamic object and is
2448           // referenced strongly in a regular object, then mark the
2449           // dynamic object as needed.  This is used to implement
2450           // --as-needed.
2451           if (sym->is_from_dynobj()
2452               && sym->in_reg()
2453               && !sym->is_undef_binding_weak())
2454             sym->object()->set_is_needed();
2455
2456           // Record any version information, except those from
2457           // as-needed libraries not seen to be needed.  Note that the
2458           // is_needed state for such libraries can change in this loop.
2459           if (sym->version() != NULL)
2460             {
2461               if (!sym->is_from_dynobj()
2462                   || !sym->object()->as_needed()
2463                   || sym->object()->is_needed())
2464                 versions->record_version(this, dynpool, sym);
2465               else
2466                 as_needed_sym.push_back(sym);
2467             }
2468         }
2469     }
2470
2471   // Process version information for symbols from as-needed libraries.
2472   for (std::vector<Symbol*>::iterator p = as_needed_sym.begin();
2473        p != as_needed_sym.end();
2474        ++p)
2475     {
2476       Symbol* sym = *p;
2477
2478       if (sym->object()->is_needed())
2479         versions->record_version(this, dynpool, sym);
2480       else
2481         sym->clear_version();
2482     }
2483
2484   // Finish up the versions.  In some cases this may add new dynamic
2485   // symbols.
2486   index = versions->finalize(this, index, syms);
2487
2488   return index;
2489 }
2490
2491 // Set the final values for all the symbols.  The index of the first
2492 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2493 // file offset OFF.  Add their names to POOL.  Return the new file
2494 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2495
2496 off_t
2497 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2498                        size_t dyncount, Stringpool* pool,
2499                        unsigned int* plocal_symcount)
2500 {
2501   off_t ret;
2502
2503   gold_assert(*plocal_symcount != 0);
2504   this->first_global_index_ = *plocal_symcount;
2505
2506   this->dynamic_offset_ = dynoff;
2507   this->first_dynamic_global_index_ = dyn_global_index;
2508   this->dynamic_count_ = dyncount;
2509
2510   if (parameters->target().get_size() == 32)
2511     {
2512 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2513       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2514 #else
2515       gold_unreachable();
2516 #endif
2517     }
2518   else if (parameters->target().get_size() == 64)
2519     {
2520 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2521       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2522 #else
2523       gold_unreachable();
2524 #endif
2525     }
2526   else
2527     gold_unreachable();
2528
2529   // Now that we have the final symbol table, we can reliably note
2530   // which symbols should get warnings.
2531   this->warnings_.note_warnings(this);
2532
2533   return ret;
2534 }
2535
2536 // SYM is going into the symbol table at *PINDEX.  Add the name to
2537 // POOL, update *PINDEX and *POFF.
2538
2539 template<int size>
2540 void
2541 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2542                                   unsigned int* pindex, off_t* poff)
2543 {
2544   sym->set_symtab_index(*pindex);
2545   if (sym->version() == NULL || !parameters->options().relocatable())
2546     pool->add(sym->name(), false, NULL);
2547   else
2548     pool->add(sym->versioned_name(), true, NULL);
2549   ++*pindex;
2550   *poff += elfcpp::Elf_sizes<size>::sym_size;
2551 }
2552
2553 // Set the final value for all the symbols.  This is called after
2554 // Layout::finalize, so all the output sections have their final
2555 // address.
2556
2557 template<int size>
2558 off_t
2559 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2560                              unsigned int* plocal_symcount)
2561 {
2562   off = align_address(off, size >> 3);
2563   this->offset_ = off;
2564
2565   unsigned int index = *plocal_symcount;
2566   const unsigned int orig_index = index;
2567
2568   // First do all the symbols which have been forced to be local, as
2569   // they must appear before all global symbols.
2570   for (Forced_locals::iterator p = this->forced_locals_.begin();
2571        p != this->forced_locals_.end();
2572        ++p)
2573     {
2574       Symbol* sym = *p;
2575       gold_assert(sym->is_forced_local());
2576       if (this->sized_finalize_symbol<size>(sym))
2577         {
2578           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2579           ++*plocal_symcount;
2580         }
2581     }
2582
2583   // Now do all the remaining symbols.
2584   for (Symbol_table_type::iterator p = this->table_.begin();
2585        p != this->table_.end();
2586        ++p)
2587     {
2588       Symbol* sym = p->second;
2589       if (this->sized_finalize_symbol<size>(sym))
2590         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2591     }
2592
2593   this->output_count_ = index - orig_index;
2594
2595   return off;
2596 }
2597
2598 // Compute the final value of SYM and store status in location PSTATUS.
2599 // During relaxation, this may be called multiple times for a symbol to
2600 // compute its would-be final value in each relaxation pass.
2601
2602 template<int size>
2603 typename Sized_symbol<size>::Value_type
2604 Symbol_table::compute_final_value(
2605     const Sized_symbol<size>* sym,
2606     Compute_final_value_status* pstatus) const
2607 {
2608   typedef typename Sized_symbol<size>::Value_type Value_type;
2609   Value_type value;
2610
2611   switch (sym->source())
2612     {
2613     case Symbol::FROM_OBJECT:
2614       {
2615         bool is_ordinary;
2616         unsigned int shndx = sym->shndx(&is_ordinary);
2617
2618         if (!is_ordinary
2619             && shndx != elfcpp::SHN_ABS
2620             && !Symbol::is_common_shndx(shndx))
2621           {
2622             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2623             return 0;
2624           }
2625
2626         Object* symobj = sym->object();
2627         if (symobj->is_dynamic())
2628           {
2629             value = 0;
2630             shndx = elfcpp::SHN_UNDEF;
2631           }
2632         else if (symobj->pluginobj() != NULL)
2633           {
2634             value = 0;
2635             shndx = elfcpp::SHN_UNDEF;
2636           }
2637         else if (shndx == elfcpp::SHN_UNDEF)
2638           value = 0;
2639         else if (!is_ordinary
2640                  && (shndx == elfcpp::SHN_ABS
2641                      || Symbol::is_common_shndx(shndx)))
2642           value = sym->value();
2643         else
2644           {
2645             Relobj* relobj = static_cast<Relobj*>(symobj);
2646             Output_section* os = relobj->output_section(shndx);
2647
2648             if (this->is_section_folded(relobj, shndx))
2649               {
2650                 gold_assert(os == NULL);
2651                 // Get the os of the section it is folded onto.
2652                 Section_id folded = this->icf_->get_folded_section(relobj,
2653                                                                    shndx);
2654                 gold_assert(folded.first != NULL);
2655                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2656                 unsigned folded_shndx = folded.second;
2657
2658                 os = folded_obj->output_section(folded_shndx);
2659                 gold_assert(os != NULL);
2660
2661                 // Replace (relobj, shndx) with canonical ICF input section.
2662                 shndx = folded_shndx;
2663                 relobj = folded_obj;
2664               }
2665
2666             uint64_t secoff64 = relobj->output_section_offset(shndx);
2667             if (os == NULL)
2668               {
2669                 bool static_or_reloc = (parameters->doing_static_link() ||
2670                                         parameters->options().relocatable());
2671                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2672
2673                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2674                 return 0;
2675               }
2676
2677             if (secoff64 == -1ULL)
2678               {
2679                 // The section needs special handling (e.g., a merge section).
2680
2681                 value = os->output_address(relobj, shndx, sym->value());
2682               }
2683             else
2684               {
2685                 Value_type secoff =
2686                   convert_types<Value_type, uint64_t>(secoff64);
2687                 if (sym->type() == elfcpp::STT_TLS)
2688                   value = sym->value() + os->tls_offset() + secoff;
2689                 else
2690                   value = sym->value() + os->address() + secoff;
2691               }
2692           }
2693       }
2694       break;
2695
2696     case Symbol::IN_OUTPUT_DATA:
2697       {
2698         Output_data* od = sym->output_data();
2699         value = sym->value();
2700         if (sym->type() != elfcpp::STT_TLS)
2701           value += od->address();
2702         else
2703           {
2704             Output_section* os = od->output_section();
2705             gold_assert(os != NULL);
2706             value += os->tls_offset() + (od->address() - os->address());
2707           }
2708         if (sym->offset_is_from_end())
2709           value += od->data_size();
2710       }
2711       break;
2712
2713     case Symbol::IN_OUTPUT_SEGMENT:
2714       {
2715         Output_segment* os = sym->output_segment();
2716         value = sym->value();
2717         if (sym->type() != elfcpp::STT_TLS)
2718           value += os->vaddr();
2719         switch (sym->offset_base())
2720           {
2721           case Symbol::SEGMENT_START:
2722             break;
2723           case Symbol::SEGMENT_END:
2724             value += os->memsz();
2725             break;
2726           case Symbol::SEGMENT_BSS:
2727             value += os->filesz();
2728             break;
2729           default:
2730             gold_unreachable();
2731           }
2732       }
2733       break;
2734
2735     case Symbol::IS_CONSTANT:
2736       value = sym->value();
2737       break;
2738
2739     case Symbol::IS_UNDEFINED:
2740       value = 0;
2741       break;
2742
2743     default:
2744       gold_unreachable();
2745     }
2746
2747   *pstatus = CFVS_OK;
2748   return value;
2749 }
2750
2751 // Finalize the symbol SYM.  This returns true if the symbol should be
2752 // added to the symbol table, false otherwise.
2753
2754 template<int size>
2755 bool
2756 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2757 {
2758   typedef typename Sized_symbol<size>::Value_type Value_type;
2759
2760   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2761
2762   // The default version of a symbol may appear twice in the symbol
2763   // table.  We only need to finalize it once.
2764   if (sym->has_symtab_index())
2765     return false;
2766
2767   if (!sym->in_reg())
2768     {
2769       gold_assert(!sym->has_symtab_index());
2770       sym->set_symtab_index(-1U);
2771       gold_assert(sym->dynsym_index() == -1U);
2772       return false;
2773     }
2774
2775   // If the symbol is only present on plugin files, the plugin decided we
2776   // don't need it.
2777   if (!sym->in_real_elf())
2778     {
2779       gold_assert(!sym->has_symtab_index());
2780       sym->set_symtab_index(-1U);
2781       return false;
2782     }
2783
2784   // Compute final symbol value.
2785   Compute_final_value_status status;
2786   Value_type value = this->compute_final_value(sym, &status);
2787
2788   switch (status)
2789     {
2790     case CFVS_OK:
2791       break;
2792     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2793       {
2794         bool is_ordinary;
2795         unsigned int shndx = sym->shndx(&is_ordinary);
2796         gold_error(_("%s: unsupported symbol section 0x%x"),
2797                    sym->demangled_name().c_str(), shndx);
2798       }
2799       break;
2800     case CFVS_NO_OUTPUT_SECTION:
2801       sym->set_symtab_index(-1U);
2802       return false;
2803     default:
2804       gold_unreachable();
2805     }
2806
2807   sym->set_value(value);
2808
2809   if (parameters->options().strip_all()
2810       || !parameters->options().should_retain_symbol(sym->name()))
2811     {
2812       sym->set_symtab_index(-1U);
2813       return false;
2814     }
2815
2816   return true;
2817 }
2818
2819 // Write out the global symbols.
2820
2821 void
2822 Symbol_table::write_globals(const Stringpool* sympool,
2823                             const Stringpool* dynpool,
2824                             Output_symtab_xindex* symtab_xindex,
2825                             Output_symtab_xindex* dynsym_xindex,
2826                             Output_file* of) const
2827 {
2828   switch (parameters->size_and_endianness())
2829     {
2830 #ifdef HAVE_TARGET_32_LITTLE
2831     case Parameters::TARGET_32_LITTLE:
2832       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2833                                            dynsym_xindex, of);
2834       break;
2835 #endif
2836 #ifdef HAVE_TARGET_32_BIG
2837     case Parameters::TARGET_32_BIG:
2838       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2839                                           dynsym_xindex, of);
2840       break;
2841 #endif
2842 #ifdef HAVE_TARGET_64_LITTLE
2843     case Parameters::TARGET_64_LITTLE:
2844       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2845                                            dynsym_xindex, of);
2846       break;
2847 #endif
2848 #ifdef HAVE_TARGET_64_BIG
2849     case Parameters::TARGET_64_BIG:
2850       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2851                                           dynsym_xindex, of);
2852       break;
2853 #endif
2854     default:
2855       gold_unreachable();
2856     }
2857 }
2858
2859 // Write out the global symbols.
2860
2861 template<int size, bool big_endian>
2862 void
2863 Symbol_table::sized_write_globals(const Stringpool* sympool,
2864                                   const Stringpool* dynpool,
2865                                   Output_symtab_xindex* symtab_xindex,
2866                                   Output_symtab_xindex* dynsym_xindex,
2867                                   Output_file* of) const
2868 {
2869   const Target& target = parameters->target();
2870
2871   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2872
2873   const unsigned int output_count = this->output_count_;
2874   const section_size_type oview_size = output_count * sym_size;
2875   const unsigned int first_global_index = this->first_global_index_;
2876   unsigned char* psyms;
2877   if (this->offset_ == 0 || output_count == 0)
2878     psyms = NULL;
2879   else
2880     psyms = of->get_output_view(this->offset_, oview_size);
2881
2882   const unsigned int dynamic_count = this->dynamic_count_;
2883   const section_size_type dynamic_size = dynamic_count * sym_size;
2884   const unsigned int first_dynamic_global_index =
2885     this->first_dynamic_global_index_;
2886   unsigned char* dynamic_view;
2887   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2888     dynamic_view = NULL;
2889   else
2890     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2891
2892   for (Symbol_table_type::const_iterator p = this->table_.begin();
2893        p != this->table_.end();
2894        ++p)
2895     {
2896       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2897
2898       // Possibly warn about unresolved symbols in shared libraries.
2899       this->warn_about_undefined_dynobj_symbol(sym);
2900
2901       unsigned int sym_index = sym->symtab_index();
2902       unsigned int dynsym_index;
2903       if (dynamic_view == NULL)
2904         dynsym_index = -1U;
2905       else
2906         dynsym_index = sym->dynsym_index();
2907
2908       if (sym_index == -1U && dynsym_index == -1U)
2909         {
2910           // This symbol is not included in the output file.
2911           continue;
2912         }
2913
2914       unsigned int shndx;
2915       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2916       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2917       elfcpp::STB binding = sym->binding();
2918
2919       // If --no-gnu-unique is set, change STB_GNU_UNIQUE to STB_GLOBAL.
2920       if (binding == elfcpp::STB_GNU_UNIQUE
2921           && !parameters->options().gnu_unique())
2922         binding = elfcpp::STB_GLOBAL;
2923
2924       switch (sym->source())
2925         {
2926         case Symbol::FROM_OBJECT:
2927           {
2928             bool is_ordinary;
2929             unsigned int in_shndx = sym->shndx(&is_ordinary);
2930
2931             if (!is_ordinary
2932                 && in_shndx != elfcpp::SHN_ABS
2933                 && !Symbol::is_common_shndx(in_shndx))
2934               {
2935                 gold_error(_("%s: unsupported symbol section 0x%x"),
2936                            sym->demangled_name().c_str(), in_shndx);
2937                 shndx = in_shndx;
2938               }
2939             else
2940               {
2941                 Object* symobj = sym->object();
2942                 if (symobj->is_dynamic())
2943                   {
2944                     if (sym->needs_dynsym_value())
2945                       dynsym_value = target.dynsym_value(sym);
2946                     shndx = elfcpp::SHN_UNDEF;
2947                     if (sym->is_undef_binding_weak())
2948                       binding = elfcpp::STB_WEAK;
2949                     else
2950                       binding = elfcpp::STB_GLOBAL;
2951                   }
2952                 else if (symobj->pluginobj() != NULL)
2953                   shndx = elfcpp::SHN_UNDEF;
2954                 else if (in_shndx == elfcpp::SHN_UNDEF
2955                          || (!is_ordinary
2956                              && (in_shndx == elfcpp::SHN_ABS
2957                                  || Symbol::is_common_shndx(in_shndx))))
2958                   shndx = in_shndx;
2959                 else
2960                   {
2961                     Relobj* relobj = static_cast<Relobj*>(symobj);
2962                     Output_section* os = relobj->output_section(in_shndx);
2963                     if (this->is_section_folded(relobj, in_shndx))
2964                       {
2965                         // This global symbol must be written out even though
2966                         // it is folded.
2967                         // Get the os of the section it is folded onto.
2968                         Section_id folded =
2969                              this->icf_->get_folded_section(relobj, in_shndx);
2970                         gold_assert(folded.first !=NULL);
2971                         Relobj* folded_obj =
2972                           reinterpret_cast<Relobj*>(folded.first);
2973                         os = folded_obj->output_section(folded.second);
2974                         gold_assert(os != NULL);
2975                       }
2976                     gold_assert(os != NULL);
2977                     shndx = os->out_shndx();
2978
2979                     if (shndx >= elfcpp::SHN_LORESERVE)
2980                       {
2981                         if (sym_index != -1U)
2982                           symtab_xindex->add(sym_index, shndx);
2983                         if (dynsym_index != -1U)
2984                           dynsym_xindex->add(dynsym_index, shndx);
2985                         shndx = elfcpp::SHN_XINDEX;
2986                       }
2987
2988                     // In object files symbol values are section
2989                     // relative.
2990                     if (parameters->options().relocatable())
2991                       sym_value -= os->address();
2992                   }
2993               }
2994           }
2995           break;
2996
2997         case Symbol::IN_OUTPUT_DATA:
2998           {
2999             Output_data* od = sym->output_data();
3000
3001             shndx = od->out_shndx();
3002             if (shndx >= elfcpp::SHN_LORESERVE)
3003               {
3004                 if (sym_index != -1U)
3005                   symtab_xindex->add(sym_index, shndx);
3006                 if (dynsym_index != -1U)
3007                   dynsym_xindex->add(dynsym_index, shndx);
3008                 shndx = elfcpp::SHN_XINDEX;
3009               }
3010
3011             // In object files symbol values are section
3012             // relative.
3013             if (parameters->options().relocatable())
3014               sym_value -= od->address();
3015           }
3016           break;
3017
3018         case Symbol::IN_OUTPUT_SEGMENT:
3019           shndx = elfcpp::SHN_ABS;
3020           break;
3021
3022         case Symbol::IS_CONSTANT:
3023           shndx = elfcpp::SHN_ABS;
3024           break;
3025
3026         case Symbol::IS_UNDEFINED:
3027           shndx = elfcpp::SHN_UNDEF;
3028           break;
3029
3030         default:
3031           gold_unreachable();
3032         }
3033
3034       if (sym_index != -1U)
3035         {
3036           sym_index -= first_global_index;
3037           gold_assert(sym_index < output_count);
3038           unsigned char* ps = psyms + (sym_index * sym_size);
3039           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
3040                                                      binding, sympool, ps);
3041         }
3042
3043       if (dynsym_index != -1U)
3044         {
3045           dynsym_index -= first_dynamic_global_index;
3046           gold_assert(dynsym_index < dynamic_count);
3047           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
3048           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
3049                                                      binding, dynpool, pd);
3050           // Allow a target to adjust dynamic symbol value.
3051           parameters->target().adjust_dyn_symbol(sym, pd);
3052         }
3053     }
3054
3055   of->write_output_view(this->offset_, oview_size, psyms);
3056   if (dynamic_view != NULL)
3057     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
3058 }
3059
3060 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
3061 // strtab holding the name.
3062
3063 template<int size, bool big_endian>
3064 void
3065 Symbol_table::sized_write_symbol(
3066     Sized_symbol<size>* sym,
3067     typename elfcpp::Elf_types<size>::Elf_Addr value,
3068     unsigned int shndx,
3069     elfcpp::STB binding,
3070     const Stringpool* pool,
3071     unsigned char* p) const
3072 {
3073   elfcpp::Sym_write<size, big_endian> osym(p);
3074   if (sym->version() == NULL || !parameters->options().relocatable())
3075     osym.put_st_name(pool->get_offset(sym->name()));
3076   else
3077     osym.put_st_name(pool->get_offset(sym->versioned_name()));
3078   osym.put_st_value(value);
3079   // Use a symbol size of zero for undefined symbols from shared libraries.
3080   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
3081     osym.put_st_size(0);
3082   else
3083     osym.put_st_size(sym->symsize());
3084   elfcpp::STT type = sym->type();
3085   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
3086   if (type == elfcpp::STT_GNU_IFUNC
3087       && sym->is_from_dynobj())
3088     type = elfcpp::STT_FUNC;
3089   // A version script may have overridden the default binding.
3090   if (sym->is_forced_local())
3091     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
3092   else
3093     osym.put_st_info(elfcpp::elf_st_info(binding, type));
3094   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
3095   osym.put_st_shndx(shndx);
3096 }
3097
3098 // Check for unresolved symbols in shared libraries.  This is
3099 // controlled by the --allow-shlib-undefined option.
3100
3101 // We only warn about libraries for which we have seen all the
3102 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
3103 // which were not seen in this link.  If we didn't see a DT_NEEDED
3104 // entry, we aren't going to be able to reliably report whether the
3105 // symbol is undefined.
3106
3107 // We also don't warn about libraries found in a system library
3108 // directory (e.g., /lib or /usr/lib); we assume that those libraries
3109 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
3110 // can have undefined references satisfied by ld-linux.so.
3111
3112 inline void
3113 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
3114 {
3115   bool dummy;
3116   if (sym->source() == Symbol::FROM_OBJECT
3117       && sym->object()->is_dynamic()
3118       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
3119       && sym->binding() != elfcpp::STB_WEAK
3120       && !parameters->options().allow_shlib_undefined()
3121       && !parameters->target().is_defined_by_abi(sym)
3122       && !sym->object()->is_in_system_directory())
3123     {
3124       // A very ugly cast.
3125       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
3126       if (!dynobj->has_unknown_needed_entries())
3127         gold_undefined_symbol(sym);
3128     }
3129 }
3130
3131 // Write out a section symbol.  Return the update offset.
3132
3133 void
3134 Symbol_table::write_section_symbol(const Output_section* os,
3135                                    Output_symtab_xindex* symtab_xindex,
3136                                    Output_file* of,
3137                                    off_t offset) const
3138 {
3139   switch (parameters->size_and_endianness())
3140     {
3141 #ifdef HAVE_TARGET_32_LITTLE
3142     case Parameters::TARGET_32_LITTLE:
3143       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
3144                                                   offset);
3145       break;
3146 #endif
3147 #ifdef HAVE_TARGET_32_BIG
3148     case Parameters::TARGET_32_BIG:
3149       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
3150                                                  offset);
3151       break;
3152 #endif
3153 #ifdef HAVE_TARGET_64_LITTLE
3154     case Parameters::TARGET_64_LITTLE:
3155       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
3156                                                   offset);
3157       break;
3158 #endif
3159 #ifdef HAVE_TARGET_64_BIG
3160     case Parameters::TARGET_64_BIG:
3161       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
3162                                                  offset);
3163       break;
3164 #endif
3165     default:
3166       gold_unreachable();
3167     }
3168 }
3169
3170 // Write out a section symbol, specialized for size and endianness.
3171
3172 template<int size, bool big_endian>
3173 void
3174 Symbol_table::sized_write_section_symbol(const Output_section* os,
3175                                          Output_symtab_xindex* symtab_xindex,
3176                                          Output_file* of,
3177                                          off_t offset) const
3178 {
3179   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
3180
3181   unsigned char* pov = of->get_output_view(offset, sym_size);
3182
3183   elfcpp::Sym_write<size, big_endian> osym(pov);
3184   osym.put_st_name(0);
3185   if (parameters->options().relocatable())
3186     osym.put_st_value(0);
3187   else
3188     osym.put_st_value(os->address());
3189   osym.put_st_size(0);
3190   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
3191                                        elfcpp::STT_SECTION));
3192   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
3193
3194   unsigned int shndx = os->out_shndx();
3195   if (shndx >= elfcpp::SHN_LORESERVE)
3196     {
3197       symtab_xindex->add(os->symtab_index(), shndx);
3198       shndx = elfcpp::SHN_XINDEX;
3199     }
3200   osym.put_st_shndx(shndx);
3201
3202   of->write_output_view(offset, sym_size, pov);
3203 }
3204
3205 // Print statistical information to stderr.  This is used for --stats.
3206
3207 void
3208 Symbol_table::print_stats() const
3209 {
3210 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
3211   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
3212           program_name, this->table_.size(), this->table_.bucket_count());
3213 #else
3214   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
3215           program_name, this->table_.size());
3216 #endif
3217   this->namepool_.print_stats("symbol table stringpool");
3218 }
3219
3220 // We check for ODR violations by looking for symbols with the same
3221 // name for which the debugging information reports that they were
3222 // defined in disjoint source locations.  When comparing the source
3223 // location, we consider instances with the same base filename to be
3224 // the same.  This is because different object files/shared libraries
3225 // can include the same header file using different paths, and
3226 // different optimization settings can make the line number appear to
3227 // be a couple lines off, and we don't want to report an ODR violation
3228 // in those cases.
3229
3230 // This struct is used to compare line information, as returned by
3231 // Dwarf_line_info::one_addr2line.  It implements a < comparison
3232 // operator used with std::sort.
3233
3234 struct Odr_violation_compare
3235 {
3236   bool
3237   operator()(const std::string& s1, const std::string& s2) const
3238   {
3239     // Inputs should be of the form "dirname/filename:linenum" where
3240     // "dirname/" is optional.  We want to compare just the filename:linenum.
3241
3242     // Find the last '/' in each string.
3243     std::string::size_type s1begin = s1.rfind('/');
3244     std::string::size_type s2begin = s2.rfind('/');
3245     // If there was no '/' in a string, start at the beginning.
3246     if (s1begin == std::string::npos)
3247       s1begin = 0;
3248     if (s2begin == std::string::npos)
3249       s2begin = 0;
3250     return s1.compare(s1begin, std::string::npos,
3251                       s2, s2begin, std::string::npos) < 0;
3252   }
3253 };
3254
3255 // Returns all of the lines attached to LOC, not just the one the
3256 // instruction actually came from.
3257 std::vector<std::string>
3258 Symbol_table::linenos_from_loc(const Task* task,
3259                                const Symbol_location& loc)
3260 {
3261   // We need to lock the object in order to read it.  This
3262   // means that we have to run in a singleton Task.  If we
3263   // want to run this in a general Task for better
3264   // performance, we will need one Task for object, plus
3265   // appropriate locking to ensure that we don't conflict with
3266   // other uses of the object.  Also note, one_addr2line is not
3267   // currently thread-safe.
3268   Task_lock_obj<Object> tl(task, loc.object);
3269
3270   std::vector<std::string> result;
3271   Symbol_location code_loc = loc;
3272   parameters->target().function_location(&code_loc);
3273   // 16 is the size of the object-cache that one_addr2line should use.
3274   std::string canonical_result = Dwarf_line_info::one_addr2line(
3275       code_loc.object, code_loc.shndx, code_loc.offset, 16, &result);
3276   if (!canonical_result.empty())
3277     result.push_back(canonical_result);
3278   return result;
3279 }
3280
3281 // OutputIterator that records if it was ever assigned to.  This
3282 // allows it to be used with std::set_intersection() to check for
3283 // intersection rather than computing the intersection.
3284 struct Check_intersection
3285 {
3286   Check_intersection()
3287     : value_(false)
3288   {}
3289
3290   bool had_intersection() const
3291   { return this->value_; }
3292
3293   Check_intersection& operator++()
3294   { return *this; }
3295
3296   Check_intersection& operator*()
3297   { return *this; }
3298
3299   template<typename T>
3300   Check_intersection& operator=(const T&)
3301   {
3302     this->value_ = true;
3303     return *this;
3304   }
3305
3306  private:
3307   bool value_;
3308 };
3309
3310 // Check candidate_odr_violations_ to find symbols with the same name
3311 // but apparently different definitions (different source-file/line-no
3312 // for each line assigned to the first instruction).
3313
3314 void
3315 Symbol_table::detect_odr_violations(const Task* task,
3316                                     const char* output_file_name) const
3317 {
3318   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3319        it != candidate_odr_violations_.end();
3320        ++it)
3321     {
3322       const char* const symbol_name = it->first;
3323
3324       std::string first_object_name;
3325       std::vector<std::string> first_object_linenos;
3326
3327       Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3328           locs = it->second.begin();
3329       const Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3330           locs_end = it->second.end();
3331       for (; locs != locs_end && first_object_linenos.empty(); ++locs)
3332         {
3333           // Save the line numbers from the first definition to
3334           // compare to the other definitions.  Ideally, we'd compare
3335           // every definition to every other, but we don't want to
3336           // take O(N^2) time to do this.  This shortcut may cause
3337           // false negatives that appear or disappear depending on the
3338           // link order, but it won't cause false positives.
3339           first_object_name = locs->object->name();
3340           first_object_linenos = this->linenos_from_loc(task, *locs);
3341         }
3342       if (first_object_linenos.empty())
3343         continue;
3344
3345       // Sort by Odr_violation_compare to make std::set_intersection work.
3346       std::string first_object_canonical_result = first_object_linenos.back();
3347       std::sort(first_object_linenos.begin(), first_object_linenos.end(),
3348                 Odr_violation_compare());
3349
3350       for (; locs != locs_end; ++locs)
3351         {
3352           std::vector<std::string> linenos =
3353               this->linenos_from_loc(task, *locs);
3354           // linenos will be empty if we couldn't parse the debug info.
3355           if (linenos.empty())
3356             continue;
3357           // Sort by Odr_violation_compare to make std::set_intersection work.
3358           gold_assert(!linenos.empty());
3359           std::string second_object_canonical_result = linenos.back();
3360           std::sort(linenos.begin(), linenos.end(), Odr_violation_compare());
3361
3362           Check_intersection intersection_result =
3363               std::set_intersection(first_object_linenos.begin(),
3364                                     first_object_linenos.end(),
3365                                     linenos.begin(),
3366                                     linenos.end(),
3367                                     Check_intersection(),
3368                                     Odr_violation_compare());
3369           if (!intersection_result.had_intersection())
3370             {
3371               gold_warning(_("while linking %s: symbol '%s' defined in "
3372                              "multiple places (possible ODR violation):"),
3373                            output_file_name, demangle(symbol_name).c_str());
3374               // This only prints one location from each definition,
3375               // which may not be the location we expect to intersect
3376               // with another definition.  We could print the whole
3377               // set of locations, but that seems too verbose.
3378               fprintf(stderr, _("  %s from %s\n"),
3379                       first_object_canonical_result.c_str(),
3380                       first_object_name.c_str());
3381               fprintf(stderr, _("  %s from %s\n"),
3382                       second_object_canonical_result.c_str(),
3383                       locs->object->name().c_str());
3384               // Only print one broken pair, to avoid needing to
3385               // compare against a list of the disjoint definition
3386               // locations we've found so far.  (If we kept comparing
3387               // against just the first one, we'd get a lot of
3388               // redundant complaints about the second definition
3389               // location.)
3390               break;
3391             }
3392         }
3393     }
3394   // We only call one_addr2line() in this function, so we can clear its cache.
3395   Dwarf_line_info::clear_addr2line_cache();
3396 }
3397
3398 // Warnings functions.
3399
3400 // Add a new warning.
3401
3402 void
3403 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3404                       const std::string& warning)
3405 {
3406   name = symtab->canonicalize_name(name);
3407   this->warnings_[name].set(obj, warning);
3408 }
3409
3410 // Look through the warnings and mark the symbols for which we should
3411 // warn.  This is called during Layout::finalize when we know the
3412 // sources for all the symbols.
3413
3414 void
3415 Warnings::note_warnings(Symbol_table* symtab)
3416 {
3417   for (Warning_table::iterator p = this->warnings_.begin();
3418        p != this->warnings_.end();
3419        ++p)
3420     {
3421       Symbol* sym = symtab->lookup(p->first, NULL);
3422       if (sym != NULL
3423           && sym->source() == Symbol::FROM_OBJECT
3424           && sym->object() == p->second.object)
3425         sym->set_has_warning();
3426     }
3427 }
3428
3429 // Issue a warning.  This is called when we see a relocation against a
3430 // symbol for which has a warning.
3431
3432 template<int size, bool big_endian>
3433 void
3434 Warnings::issue_warning(const Symbol* sym,
3435                         const Relocate_info<size, big_endian>* relinfo,
3436                         size_t relnum, off_t reloffset) const
3437 {
3438   gold_assert(sym->has_warning());
3439
3440   // We don't want to issue a warning for a relocation against the
3441   // symbol in the same object file in which the symbol is defined.
3442   if (sym->object() == relinfo->object)
3443     return;
3444
3445   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3446   gold_assert(p != this->warnings_.end());
3447   gold_warning_at_location(relinfo, relnum, reloffset,
3448                            "%s", p->second.text.c_str());
3449 }
3450
3451 // Instantiate the templates we need.  We could use the configure
3452 // script to restrict this to only the ones needed for implemented
3453 // targets.
3454
3455 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3456 template
3457 void
3458 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3459 #endif
3460
3461 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3462 template
3463 void
3464 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3465 #endif
3466
3467 #ifdef HAVE_TARGET_32_LITTLE
3468 template
3469 void
3470 Symbol_table::add_from_relobj<32, false>(
3471     Sized_relobj_file<32, false>* relobj,
3472     const unsigned char* syms,
3473     size_t count,
3474     size_t symndx_offset,
3475     const char* sym_names,
3476     size_t sym_name_size,
3477     Sized_relobj_file<32, false>::Symbols* sympointers,
3478     size_t* defined);
3479 #endif
3480
3481 #ifdef HAVE_TARGET_32_BIG
3482 template
3483 void
3484 Symbol_table::add_from_relobj<32, true>(
3485     Sized_relobj_file<32, true>* relobj,
3486     const unsigned char* syms,
3487     size_t count,
3488     size_t symndx_offset,
3489     const char* sym_names,
3490     size_t sym_name_size,
3491     Sized_relobj_file<32, true>::Symbols* sympointers,
3492     size_t* defined);
3493 #endif
3494
3495 #ifdef HAVE_TARGET_64_LITTLE
3496 template
3497 void
3498 Symbol_table::add_from_relobj<64, false>(
3499     Sized_relobj_file<64, false>* relobj,
3500     const unsigned char* syms,
3501     size_t count,
3502     size_t symndx_offset,
3503     const char* sym_names,
3504     size_t sym_name_size,
3505     Sized_relobj_file<64, false>::Symbols* sympointers,
3506     size_t* defined);
3507 #endif
3508
3509 #ifdef HAVE_TARGET_64_BIG
3510 template
3511 void
3512 Symbol_table::add_from_relobj<64, true>(
3513     Sized_relobj_file<64, true>* relobj,
3514     const unsigned char* syms,
3515     size_t count,
3516     size_t symndx_offset,
3517     const char* sym_names,
3518     size_t sym_name_size,
3519     Sized_relobj_file<64, true>::Symbols* sympointers,
3520     size_t* defined);
3521 #endif
3522
3523 #ifdef HAVE_TARGET_32_LITTLE
3524 template
3525 Symbol*
3526 Symbol_table::add_from_pluginobj<32, false>(
3527     Sized_pluginobj<32, false>* obj,
3528     const char* name,
3529     const char* ver,
3530     elfcpp::Sym<32, false>* sym);
3531 #endif
3532
3533 #ifdef HAVE_TARGET_32_BIG
3534 template
3535 Symbol*
3536 Symbol_table::add_from_pluginobj<32, true>(
3537     Sized_pluginobj<32, true>* obj,
3538     const char* name,
3539     const char* ver,
3540     elfcpp::Sym<32, true>* sym);
3541 #endif
3542
3543 #ifdef HAVE_TARGET_64_LITTLE
3544 template
3545 Symbol*
3546 Symbol_table::add_from_pluginobj<64, false>(
3547     Sized_pluginobj<64, false>* obj,
3548     const char* name,
3549     const char* ver,
3550     elfcpp::Sym<64, false>* sym);
3551 #endif
3552
3553 #ifdef HAVE_TARGET_64_BIG
3554 template
3555 Symbol*
3556 Symbol_table::add_from_pluginobj<64, true>(
3557     Sized_pluginobj<64, true>* obj,
3558     const char* name,
3559     const char* ver,
3560     elfcpp::Sym<64, true>* sym);
3561 #endif
3562
3563 #ifdef HAVE_TARGET_32_LITTLE
3564 template
3565 void
3566 Symbol_table::add_from_dynobj<32, false>(
3567     Sized_dynobj<32, false>* dynobj,
3568     const unsigned char* syms,
3569     size_t count,
3570     const char* sym_names,
3571     size_t sym_name_size,
3572     const unsigned char* versym,
3573     size_t versym_size,
3574     const std::vector<const char*>* version_map,
3575     Sized_relobj_file<32, false>::Symbols* sympointers,
3576     size_t* defined);
3577 #endif
3578
3579 #ifdef HAVE_TARGET_32_BIG
3580 template
3581 void
3582 Symbol_table::add_from_dynobj<32, true>(
3583     Sized_dynobj<32, true>* dynobj,
3584     const unsigned char* syms,
3585     size_t count,
3586     const char* sym_names,
3587     size_t sym_name_size,
3588     const unsigned char* versym,
3589     size_t versym_size,
3590     const std::vector<const char*>* version_map,
3591     Sized_relobj_file<32, true>::Symbols* sympointers,
3592     size_t* defined);
3593 #endif
3594
3595 #ifdef HAVE_TARGET_64_LITTLE
3596 template
3597 void
3598 Symbol_table::add_from_dynobj<64, false>(
3599     Sized_dynobj<64, false>* dynobj,
3600     const unsigned char* syms,
3601     size_t count,
3602     const char* sym_names,
3603     size_t sym_name_size,
3604     const unsigned char* versym,
3605     size_t versym_size,
3606     const std::vector<const char*>* version_map,
3607     Sized_relobj_file<64, false>::Symbols* sympointers,
3608     size_t* defined);
3609 #endif
3610
3611 #ifdef HAVE_TARGET_64_BIG
3612 template
3613 void
3614 Symbol_table::add_from_dynobj<64, true>(
3615     Sized_dynobj<64, true>* dynobj,
3616     const unsigned char* syms,
3617     size_t count,
3618     const char* sym_names,
3619     size_t sym_name_size,
3620     const unsigned char* versym,
3621     size_t versym_size,
3622     const std::vector<const char*>* version_map,
3623     Sized_relobj_file<64, true>::Symbols* sympointers,
3624     size_t* defined);
3625 #endif
3626
3627 #ifdef HAVE_TARGET_32_LITTLE
3628 template
3629 Sized_symbol<32>*
3630 Symbol_table::add_from_incrobj(
3631     Object* obj,
3632     const char* name,
3633     const char* ver,
3634     elfcpp::Sym<32, false>* sym);
3635 #endif
3636
3637 #ifdef HAVE_TARGET_32_BIG
3638 template
3639 Sized_symbol<32>*
3640 Symbol_table::add_from_incrobj(
3641     Object* obj,
3642     const char* name,
3643     const char* ver,
3644     elfcpp::Sym<32, true>* sym);
3645 #endif
3646
3647 #ifdef HAVE_TARGET_64_LITTLE
3648 template
3649 Sized_symbol<64>*
3650 Symbol_table::add_from_incrobj(
3651     Object* obj,
3652     const char* name,
3653     const char* ver,
3654     elfcpp::Sym<64, false>* sym);
3655 #endif
3656
3657 #ifdef HAVE_TARGET_64_BIG
3658 template
3659 Sized_symbol<64>*
3660 Symbol_table::add_from_incrobj(
3661     Object* obj,
3662     const char* name,
3663     const char* ver,
3664     elfcpp::Sym<64, true>* sym);
3665 #endif
3666
3667 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3668 template
3669 void
3670 Symbol_table::define_with_copy_reloc<32>(
3671     Sized_symbol<32>* sym,
3672     Output_data* posd,
3673     elfcpp::Elf_types<32>::Elf_Addr value);
3674 #endif
3675
3676 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3677 template
3678 void
3679 Symbol_table::define_with_copy_reloc<64>(
3680     Sized_symbol<64>* sym,
3681     Output_data* posd,
3682     elfcpp::Elf_types<64>::Elf_Addr value);
3683 #endif
3684
3685 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3686 template
3687 void
3688 Sized_symbol<32>::init_output_data(const char* name, const char* version,
3689                                    Output_data* od, Value_type value,
3690                                    Size_type symsize, elfcpp::STT type,
3691                                    elfcpp::STB binding,
3692                                    elfcpp::STV visibility,
3693                                    unsigned char nonvis,
3694                                    bool offset_is_from_end,
3695                                    bool is_predefined);
3696 #endif
3697
3698 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3699 template
3700 void
3701 Sized_symbol<64>::init_output_data(const char* name, const char* version,
3702                                    Output_data* od, Value_type value,
3703                                    Size_type symsize, elfcpp::STT type,
3704                                    elfcpp::STB binding,
3705                                    elfcpp::STV visibility,
3706                                    unsigned char nonvis,
3707                                    bool offset_is_from_end,
3708                                    bool is_predefined);
3709 #endif
3710
3711 #ifdef HAVE_TARGET_32_LITTLE
3712 template
3713 void
3714 Warnings::issue_warning<32, false>(const Symbol* sym,
3715                                    const Relocate_info<32, false>* relinfo,
3716                                    size_t relnum, off_t reloffset) const;
3717 #endif
3718
3719 #ifdef HAVE_TARGET_32_BIG
3720 template
3721 void
3722 Warnings::issue_warning<32, true>(const Symbol* sym,
3723                                   const Relocate_info<32, true>* relinfo,
3724                                   size_t relnum, off_t reloffset) const;
3725 #endif
3726
3727 #ifdef HAVE_TARGET_64_LITTLE
3728 template
3729 void
3730 Warnings::issue_warning<64, false>(const Symbol* sym,
3731                                    const Relocate_info<64, false>* relinfo,
3732                                    size_t relnum, off_t reloffset) const;
3733 #endif
3734
3735 #ifdef HAVE_TARGET_64_BIG
3736 template
3737 void
3738 Warnings::issue_warning<64, true>(const Symbol* sym,
3739                                   const Relocate_info<64, true>* relinfo,
3740                                   size_t relnum, off_t reloffset) const;
3741 #endif
3742
3743 } // End namespace gold.