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   // or the symbol should be globally unique (GNU_UNIQUE),
 423   // and the symbol is defined in a regular object and is
 424   // externally visible, we need to add it.
 425   if ((parameters->options().export_dynamic()
 426        || parameters->options().shared()
 427        || (parameters->options().gnu_unique()
 428            && this->binding() == elfcpp::STB_GNU_UNIQUE))
 429       && !this->is_from_dynobj()
 430       && !this->is_undefined()
 431       && this->is_externally_visible())
 432     return true;
 433
 434   return false;
 435 }
 436
 437 // Return true if the final value of this symbol is known at link
 438 // time.
 439
 440 bool
 441 Symbol::final_value_is_known() const
 442 {
 443   // If we are not generating an executable, then no final values are
 444   // known, since they will change at runtime, with the exception of
 445   // TLS symbols in a position-independent executable.
 446   if ((parameters->options().output_is_position_independent()
 447        || parameters->options().relocatable())
 448       && !(this->type() == elfcpp::STT_TLS
 449            && parameters->options().pie()))
 450     return false;
 451
 452   // If the symbol is not from an object file, and is not undefined,
 453   // then it is defined, and known.
 454   if (this->source_ != FROM_OBJECT)
 455     {
 456       if (this->source_ != IS_UNDEFINED)
 457         return true;
 458     }
 459   else
 460     {
 461       // If the symbol is from a dynamic object, then the final value
 462       // is not known.
 463       if (this->object()->is_dynamic())
 464         return false;
 465
 466       // If the symbol is not undefined (it is defined or common),
 467       // then the final value is known.
 468       if (!this->is_undefined())
 469         return true;
 470     }
 471
 472   // If the symbol is undefined, then whether the final value is known
 473   // depends on whether we are doing a static link.  If we are doing a
 474   // dynamic link, then the final value could be filled in at runtime.
 475   // This could reasonably be the case for a weak undefined symbol.
 476   return parameters->doing_static_link();
 477 }
 478
 479 // Return the output section where this symbol is defined.
 480
 481 Output_section*
 482 Symbol::output_section() const
 483 {
 484   switch (this->source_)
 485     {
 486     case FROM_OBJECT:
 487       {
 488         unsigned int shndx = this->u_.from_object.shndx;
 489         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
 490           {
 491             gold_assert(!this->u_.from_object.object->is_dynamic());
 492             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
 493             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
 494             return relobj->output_section(shndx);
 495           }
 496         return NULL;
 497       }
 498
 499     case IN_OUTPUT_DATA:
 500       return this->u_.in_output_data.output_data->output_section();
 501
 502     case IN_OUTPUT_SEGMENT:
 503     case IS_CONSTANT:
 504     case IS_UNDEFINED:
 505       return NULL;
 506
 507     default:
 508       gold_unreachable();
 509     }
 510 }
 511
 512 // Set the symbol's output section.  This is used for symbols defined
 513 // in scripts.  This should only be called after the symbol table has
 514 // been finalized.
 515
 516 void
 517 Symbol::set_output_section(Output_section* os)
 518 {
 519   switch (this->source_)
 520     {
 521     case FROM_OBJECT:
 522     case IN_OUTPUT_DATA:
 523       gold_assert(this->output_section() == os);
 524       break;
 525     case IS_CONSTANT:
 526       this->source_ = IN_OUTPUT_DATA;
 527       this->u_.in_output_data.output_data = os;
 528       this->u_.in_output_data.offset_is_from_end = false;
 529       break;
 530     case IN_OUTPUT_SEGMENT:
 531     case IS_UNDEFINED:
 532     default:
 533       gold_unreachable();
 534     }
 535 }
 536
 537 // Set the symbol's output segment.  This is used for pre-defined
 538 // symbols whose segments aren't known until after layout is done
 539 // (e.g., __ehdr_start).
 540
 541 void
 542 Symbol::set_output_segment(Output_segment* os, Segment_offset_base base)
 543 {
 544   gold_assert(this->is_predefined_);
 545   this->source_ = IN_OUTPUT_SEGMENT;
 546   this->u_.in_output_segment.output_segment = os;
 547   this->u_.in_output_segment.offset_base = base;
 548 }
 549
 550 // Set the symbol to undefined.  This is used for pre-defined
 551 // symbols whose segments aren't known until after layout is done
 552 // (e.g., __ehdr_start).
 553
 554 void
 555 Symbol::set_undefined()
 556 {
 557   this->source_ = IS_UNDEFINED;
 558   this->is_predefined_ = false;
 559 }
 560
 561 // Class Symbol_table.
 562
 563 Symbol_table::Symbol_table(unsigned int count,
 564                            const Version_script_info& version_script)
 565   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
 566     forwarders_(), commons_(), tls_commons_(), small_commons_(),
 567     large_commons_(), forced_locals_(), warnings_(),
 568     version_script_(version_script), gc_(NULL), icf_(NULL)
 569 {
 570   namepool_.reserve(count);
 571 }
 572
 573 Symbol_table::~Symbol_table()
 574 {
 575 }
 576
 577 // The symbol table key equality function.  This is called with
 578 // Stringpool keys.
 579
 580 inline bool
 581 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
 582                                           const Symbol_table_key& k2) const
 583 {
 584   return k1.first == k2.first && k1.second == k2.second;
 585 }
 586
 587 bool
 588 Symbol_table::is_section_folded(Relobj* obj, unsigned int shndx) const
 589 {
 590   return (parameters->options().icf_enabled()
 591           && this->icf_->is_section_folded(obj, shndx));
 592 }
 593
 594 // For symbols that have been listed with a -u or --export-dynamic-symbol
 595 // option, add them to the work list to avoid gc'ing them.
 596
 597 void
 598 Symbol_table::gc_mark_undef_symbols(Layout* layout)
 599 {
 600   for (options::String_set::const_iterator p =
 601          parameters->options().undefined_begin();
 602        p != parameters->options().undefined_end();
 603        ++p)
 604     {
 605       const char* name = p->c_str();
 606       Symbol* sym = this->lookup(name);
 607       gold_assert(sym != NULL);
 608       if (sym->source() == Symbol::FROM_OBJECT
 609           && !sym->object()->is_dynamic())
 610         {
 611           this->gc_mark_symbol(sym);
 612         }
 613     }
 614
 615   for (options::String_set::const_iterator p =
 616          parameters->options().export_dynamic_symbol_begin();
 617        p != parameters->options().export_dynamic_symbol_end();
 618        ++p)
 619     {
 620       const char* name = p->c_str();
 621       Symbol* sym = this->lookup(name);
 622       // It's not an error if a symbol named by --export-dynamic-symbol
 623       // is undefined.
 624       if (sym != NULL
 625           && sym->source() == Symbol::FROM_OBJECT
 626           && !sym->object()->is_dynamic())
 627         {
 628           this->gc_mark_symbol(sym);
 629         }
 630     }
 631
 632   for (Script_options::referenced_const_iterator p =
 633          layout->script_options()->referenced_begin();
 634        p != layout->script_options()->referenced_end();
 635        ++p)
 636     {
 637       Symbol* sym = this->lookup(p->c_str());
 638       gold_assert(sym != NULL);
 639       if (sym->source() == Symbol::FROM_OBJECT
 640           && !sym->object()->is_dynamic())
 641         {
 642           this->gc_mark_symbol(sym);
 643         }
 644     }
 645 }
 646
 647 void
 648 Symbol_table::gc_mark_symbol(Symbol* sym)
 649 {
 650   // Add the object and section to the work list.
 651   bool is_ordinary;
 652   unsigned int shndx = sym->shndx(&is_ordinary);
 653   if (is_ordinary && shndx != elfcpp::SHN_UNDEF && !sym->object()->is_dynamic())
 654     {
 655       gold_assert(this->gc_!= NULL);
 656       Relobj* relobj = static_cast<Relobj*>(sym->object());
 657       this->gc_->worklist().push_back(Section_id(relobj, shndx));
 658     }
 659   parameters->target().gc_mark_symbol(this, sym);
 660 }
 661
 662 // When doing garbage collection, keep symbols that have been seen in
 663 // dynamic objects.
 664 inline void
 665 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
 666 {
 667   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
 668       && !sym->object()->is_dynamic())
 669     this->gc_mark_symbol(sym);
 670 }
 671
 672 // Make TO a symbol which forwards to FROM.
 673
 674 void
 675 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
 676 {
 677   gold_assert(from != to);
 678   gold_assert(!from->is_forwarder() && !to->is_forwarder());
 679   this->forwarders_[from] = to;
 680   from->set_forwarder();
 681 }
 682
 683 // Resolve the forwards from FROM, returning the real symbol.
 684
 685 Symbol*
 686 Symbol_table::resolve_forwards(const Symbol* from) const
 687 {
 688   gold_assert(from->is_forwarder());
 689   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
 690     this->forwarders_.find(from);
 691   gold_assert(p != this->forwarders_.end());
 692   return p->second;
 693 }
 694
 695 // Look up a symbol by name.
 696
 697 Symbol*
 698 Symbol_table::lookup(const char* name, const char* version) const
 699 {
 700   Stringpool::Key name_key;
 701   name = this->namepool_.find(name, &name_key);
 702   if (name == NULL)
 703     return NULL;
 704
 705   Stringpool::Key version_key = 0;
 706   if (version != NULL)
 707     {
 708       version = this->namepool_.find(version, &version_key);
 709       if (version == NULL)
 710         return NULL;
 711     }
 712
 713   Symbol_table_key key(name_key, version_key);
 714   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
 715   if (p == this->table_.end())
 716     return NULL;
 717   return p->second;
 718 }
 719
 720 // Resolve a Symbol with another Symbol.  This is only used in the
 721 // unusual case where there are references to both an unversioned
 722 // symbol and a symbol with a version, and we then discover that that
 723 // version is the default version.  Because this is unusual, we do
 724 // this the slow way, by converting back to an ELF symbol.
 725
 726 template<int size, bool big_endian>
 727 void
 728 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
 729 {
 730   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
 731   elfcpp::Sym_write<size, big_endian> esym(buf);
 732   // We don't bother to set the st_name or the st_shndx field.
 733   esym.put_st_value(from->value());
 734   esym.put_st_size(from->symsize());
 735   esym.put_st_info(from->binding(), from->type());
 736   esym.put_st_other(from->visibility(), from->nonvis());
 737   bool is_ordinary;
 738   unsigned int shndx = from->shndx(&is_ordinary);
 739   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
 740                 from->version(), true);
 741   if (from->in_reg())
 742     to->set_in_reg();
 743   if (from->in_dyn())
 744     to->set_in_dyn();
 745   if (parameters->options().gc_sections())
 746     this->gc_mark_dyn_syms(to);
 747 }
 748
 749 // Record that a symbol is forced to be local by a version script or
 750 // by visibility.
 751
 752 void
 753 Symbol_table::force_local(Symbol* sym)
 754 {
 755   if (!sym->is_defined() && !sym->is_common())
 756     return;
 757   if (sym->is_forced_local())
 758     {
 759       // We already got this one.
 760       return;
 761     }
 762   sym->set_is_forced_local();
 763   this->forced_locals_.push_back(sym);
 764 }
 765
 766 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
 767 // is only called for undefined symbols, when at least one --wrap
 768 // option was used.
 769
 770 const char*
 771 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
 772 {
 773   // For some targets, we need to ignore a specific character when
 774   // wrapping, and add it back later.
 775   char prefix = '\0';
 776   if (name[0] == parameters->target().wrap_char())
 777     {
 778       prefix = name[0];
 779       ++name;
 780     }
 781
 782   if (parameters->options().is_wrap(name))
 783     {
 784       // Turn NAME into __wrap_NAME.
 785       std::string s;
 786       if (prefix != '\0')
 787         s += prefix;
 788       s += "__wrap_";
 789       s += name;
 790
 791       // This will give us both the old and new name in NAMEPOOL_, but
 792       // that is OK.  Only the versions we need will wind up in the
 793       // real string table in the output file.
 794       return this->namepool_.add(s.c_str(), true, name_key);
 795     }
 796
 797   const char* const real_prefix = "__real_";
 798   const size_t real_prefix_length = strlen(real_prefix);
 799   if (strncmp(name, real_prefix, real_prefix_length) == 0
 800       && parameters->options().is_wrap(name + real_prefix_length))
 801     {
 802       // Turn __real_NAME into NAME.
 803       std::string s;
 804       if (prefix != '\0')
 805         s += prefix;
 806       s += name + real_prefix_length;
 807       return this->namepool_.add(s.c_str(), true, name_key);
 808     }
 809
 810   return name;
 811 }
 812
 813 // This is called when we see a symbol NAME/VERSION, and the symbol
 814 // already exists in the symbol table, and VERSION is marked as being
 815 // the default version.  SYM is the NAME/VERSION symbol we just added.
 816 // DEFAULT_IS_NEW is true if this is the first time we have seen the
 817 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
 818
 819 template<int size, bool big_endian>
 820 void
 821 Symbol_table::define_default_version(Sized_symbol<size>* sym,
 822                                      bool default_is_new,
 823                                      Symbol_table_type::iterator pdef)
 824 {
 825   if (default_is_new)
 826     {
 827       // This is the first time we have seen NAME/NULL.  Make
 828       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
 829       // version.
 830       pdef->second = sym;
 831       sym->set_is_default();
 832     }
 833   else if (pdef->second == sym)
 834     {
 835       // NAME/NULL already points to NAME/VERSION.  Don't mark the
 836       // symbol as the default if it is not already the default.
 837     }
 838   else
 839     {
 840       // This is the unfortunate case where we already have entries
 841       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
 842       // NAME/VERSION where VERSION is the default version.  We have
 843       // already resolved this new symbol with the existing
 844       // NAME/VERSION symbol.
 845
 846       // It's possible that NAME/NULL and NAME/VERSION are both
 847       // defined in regular objects.  This can only happen if one
 848       // object file defines foo and another defines foo@@ver.  This
 849       // is somewhat obscure, but we call it a multiple definition
 850       // error.
 851
 852       // It's possible that NAME/NULL actually has a version, in which
 853       // case it won't be the same as VERSION.  This happens with
 854       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
 855       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
 856       // then see an unadorned t2_2 in an object file and give it
 857       // version VER1 from the version script.  This looks like a
 858       // default definition for VER1, so it looks like we should merge
 859       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
 860       // not obvious that this is an error, either.  So we just punt.
 861
 862       // If one of the symbols has non-default visibility, and the
 863       // other is defined in a shared object, then they are different
 864       // symbols.
 865
 866       // Otherwise, we just resolve the symbols as though they were
 867       // the same.
 868
 869       if (pdef->second->version() != NULL)
 870         gold_assert(pdef->second->version() != sym->version());
 871       else if (sym->visibility() != elfcpp::STV_DEFAULT
 872                && pdef->second->is_from_dynobj())
 873         ;
 874       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
 875                && sym->is_from_dynobj())
 876         ;
 877       else
 878         {
 879           const Sized_symbol<size>* symdef;
 880           symdef = this->get_sized_symbol<size>(pdef->second);
 881           Symbol_table::resolve<size, big_endian>(sym, symdef);
 882           this->make_forwarder(pdef->second, sym);
 883           pdef->second = sym;
 884           sym->set_is_default();
 885         }
 886     }
 887 }
 888
 889 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
 890 // name and VERSION is the version; both are canonicalized.  DEF is
 891 // whether this is the default version.  ST_SHNDX is the symbol's
 892 // section index; IS_ORDINARY is whether this is a normal section
 893 // rather than a special code.
 894
 895 // If IS_DEFAULT_VERSION is true, then this is the definition of a
 896 // default version of a symbol.  That means that any lookup of
 897 // NAME/NULL and any lookup of NAME/VERSION should always return the
 898 // same symbol.  This is obvious for references, but in particular we
 899 // want to do this for definitions: overriding NAME/NULL should also
 900 // override NAME/VERSION.  If we don't do that, it would be very hard
 901 // to override functions in a shared library which uses versioning.
 902
 903 // We implement this by simply making both entries in the hash table
 904 // point to the same Symbol structure.  That is easy enough if this is
 905 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
 906 // that we have seen both already, in which case they will both have
 907 // independent entries in the symbol table.  We can't simply change
 908 // the symbol table entry, because we have pointers to the entries
 909 // attached to the object files.  So we mark the entry attached to the
 910 // object file as a forwarder, and record it in the forwarders_ map.
 911 // Note that entries in the hash table will never be marked as
 912 // forwarders.
 913 //
 914 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
 915 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
 916 // for a special section code.  ST_SHNDX may be modified if the symbol
 917 // is defined in a section being discarded.
 918
 919 template<int size, bool big_endian>
 920 Sized_symbol<size>*
 921 Symbol_table::add_from_object(Object* object,
 922                               const char* name,
 923                               Stringpool::Key name_key,
 924                               const char* version,
 925                               Stringpool::Key version_key,
 926                               bool is_default_version,
 927                               const elfcpp::Sym<size, big_endian>& sym,
 928                               unsigned int st_shndx,
 929                               bool is_ordinary,
 930                               unsigned int orig_st_shndx)
 931 {
 932   // Print a message if this symbol is being traced.
 933   if (parameters->options().is_trace_symbol(name))
 934     {
 935       if (orig_st_shndx == elfcpp::SHN_UNDEF)
 936         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
 937       else
 938         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
 939     }
 940
 941   // For an undefined symbol, we may need to adjust the name using
 942   // --wrap.
 943   if (orig_st_shndx == elfcpp::SHN_UNDEF
 944       && parameters->options().any_wrap())
 945     {
 946       const char* wrap_name = this->wrap_symbol(name, &name_key);
 947       if (wrap_name != name)
 948         {
 949           // If we see a reference to malloc with version GLIBC_2.0,
 950           // and we turn it into a reference to __wrap_malloc, then we
 951           // discard the version number.  Otherwise the user would be
 952           // required to specify the correct version for
 953           // __wrap_malloc.
 954           version = NULL;
 955           version_key = 0;
 956           name = wrap_name;
 957         }
 958     }
 959
 960   Symbol* const snull = NULL;
 961   std::pair<typename Symbol_table_type::iterator, bool> ins =
 962     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
 963                                        snull));
 964
 965   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
 966     std::make_pair(this->table_.end(), false);
 967   if (is_default_version)
 968     {
 969       const Stringpool::Key vnull_key = 0;
 970       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
 971                                                                      vnull_key),
 972                                                       snull));
 973     }
 974
 975   // ins.first: an iterator, which is a pointer to a pair.
 976   // ins.first->first: the key (a pair of name and version).
 977   // ins.first->second: the value (Symbol*).
 978   // ins.second: true if new entry was inserted, false if not.
 979
 980   Sized_symbol<size>* ret;
 981   bool was_undefined;
 982   bool was_common;
 983   if (!ins.second)
 984     {
 985       // We already have an entry for NAME/VERSION.
 986       ret = this->get_sized_symbol<size>(ins.first->second);
 987       gold_assert(ret != NULL);
 988
 989       was_undefined = ret->is_undefined();
 990       // Commons from plugins are just placeholders.
 991       was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
 992
 993       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
 994                     version, is_default_version);
 995       if (parameters->options().gc_sections())
 996         this->gc_mark_dyn_syms(ret);
 997
 998       if (is_default_version)
 999         this->define_default_version<size, big_endian>(ret, insdefault.second,
1000                                                        insdefault.first);
1001       else
1002         {
1003           bool dummy;
1004           if (version != NULL
1005               && ret->source() == Symbol::FROM_OBJECT
1006               && ret->object() == object
1007               && is_ordinary
1008               && ret->shndx(&dummy) == st_shndx
1009               && ret->is_default())
1010             {
1011               // We have seen NAME/VERSION already, and marked it as the
1012               // default version, but now we see a definition for
1013               // NAME/VERSION that is not the default version. This can
1014               // happen when the assembler generates two symbols for
1015               // a symbol as a result of a ".symver foo,foo@VER"
1016               // directive. We see the first unversioned symbol and
1017               // we may mark it as the default version (from a
1018               // version script); then we see the second versioned
1019               // symbol and we need to override the first.
1020               // In any other case, the two symbols should have generated
1021               // a multiple definition error.
1022               // (See PR gold/18703.)
1023               ret->set_is_not_default();
1024               const Stringpool::Key vnull_key = 0;
1025               this->table_.erase(std::make_pair(name_key, vnull_key));
1026             }
1027         }
1028     }
1029   else
1030     {
1031       // This is the first time we have seen NAME/VERSION.
1032       gold_assert(ins.first->second == NULL);
1033
1034       if (is_default_version && !insdefault.second)
1035         {
1036           // We already have an entry for NAME/NULL.  If we override
1037           // it, then change it to NAME/VERSION.
1038           ret = this->get_sized_symbol<size>(insdefault.first->second);
1039
1040           was_undefined = ret->is_undefined();
1041           // Commons from plugins are just placeholders.
1042           was_common = ret->is_common() && ret->object()->pluginobj() == NULL;
1043
1044           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
1045                         version, is_default_version);
1046           if (parameters->options().gc_sections())
1047             this->gc_mark_dyn_syms(ret);
1048           ins.first->second = ret;
1049         }
1050       else
1051         {
1052           was_undefined = false;
1053           was_common = false;
1054
1055           Sized_target<size, big_endian>* target =
1056             parameters->sized_target<size, big_endian>();
1057           if (!target->has_make_symbol())
1058             ret = new Sized_symbol<size>();
1059           else
1060             {
1061               ret = target->make_symbol();
1062               if (ret == NULL)
1063                 {
1064                   // This means that we don't want a symbol table
1065                   // entry after all.
1066                   if (!is_default_version)
1067                     this->table_.erase(ins.first);
1068                   else
1069                     {
1070                       this->table_.erase(insdefault.first);
1071                       // Inserting INSDEFAULT invalidated INS.
1072                       this->table_.erase(std::make_pair(name_key,
1073                                                         version_key));
1074                     }
1075                   return NULL;
1076                 }
1077             }
1078
1079           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
1080
1081           ins.first->second = ret;
1082           if (is_default_version)
1083             {
1084               // This is the first time we have seen NAME/NULL.  Point
1085               // it at the new entry for NAME/VERSION.
1086               gold_assert(insdefault.second);
1087               insdefault.first->second = ret;
1088             }
1089         }
1090
1091       if (is_default_version)
1092         ret->set_is_default();
1093     }
1094
1095   // Record every time we see a new undefined symbol, to speed up
1096   // archive groups.
1097   if (!was_undefined && ret->is_undefined())
1098     {
1099       ++this->saw_undefined_;
1100       if (parameters->options().has_plugins())
1101         parameters->options().plugins()->new_undefined_symbol(ret);
1102     }
1103
1104   // Keep track of common symbols, to speed up common symbol
1105   // allocation.  Don't record commons from plugin objects;
1106   // we need to wait until we see the real symbol in the
1107   // replacement file.
1108   if (!was_common && ret->is_common() && ret->object()->pluginobj() == NULL)
1109     {
1110       if (ret->type() == elfcpp::STT_TLS)
1111         this->tls_commons_.push_back(ret);
1112       else if (!is_ordinary
1113                && st_shndx == parameters->target().small_common_shndx())
1114         this->small_commons_.push_back(ret);
1115       else if (!is_ordinary
1116                && st_shndx == parameters->target().large_common_shndx())
1117         this->large_commons_.push_back(ret);
1118       else
1119         this->commons_.push_back(ret);
1120     }
1121
1122   // If we're not doing a relocatable link, then any symbol with
1123   // hidden or internal visibility is local.
1124   if ((ret->visibility() == elfcpp::STV_HIDDEN
1125        || ret->visibility() == elfcpp::STV_INTERNAL)
1126       && (ret->binding() == elfcpp::STB_GLOBAL
1127           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1128           || ret->binding() == elfcpp::STB_WEAK)
1129       && !parameters->options().relocatable())
1130     this->force_local(ret);
1131
1132   return ret;
1133 }
1134
1135 // Add all the symbols in a relocatable object to the hash table.
1136
1137 template<int size, bool big_endian>
1138 void
1139 Symbol_table::add_from_relobj(
1140     Sized_relobj_file<size, big_endian>* relobj,
1141     const unsigned char* syms,
1142     size_t count,
1143     size_t symndx_offset,
1144     const char* sym_names,
1145     size_t sym_name_size,
1146     typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
1147     size_t* defined)
1148 {
1149   *defined = 0;
1150
1151   gold_assert(size == parameters->target().get_size());
1152
1153   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1154
1155   const bool just_symbols = relobj->just_symbols();
1156
1157   const unsigned char* p = syms;
1158   for (size_t i = 0; i < count; ++i, p += sym_size)
1159     {
1160       (*sympointers)[i] = NULL;
1161
1162       elfcpp::Sym<size, big_endian> sym(p);
1163
1164       unsigned int st_name = sym.get_st_name();
1165       if (st_name >= sym_name_size)
1166         {
1167           relobj->error(_("bad global symbol name offset %u at %zu"),
1168                         st_name, i);
1169           continue;
1170         }
1171
1172       const char* name = sym_names + st_name;
1173
1174       if (strcmp (name, "__gnu_lto_slim") == 0)
1175         gold_info(_("%s: plugin needed to handle lto object"),
1176                   relobj->name().c_str());
1177
1178       bool is_ordinary;
1179       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1180                                                        sym.get_st_shndx(),
1181                                                        &is_ordinary);
1182       unsigned int orig_st_shndx = st_shndx;
1183       if (!is_ordinary)
1184         orig_st_shndx = elfcpp::SHN_UNDEF;
1185
1186       if (st_shndx != elfcpp::SHN_UNDEF)
1187         ++*defined;
1188
1189       // A symbol defined in a section which we are not including must
1190       // be treated as an undefined symbol.
1191       bool is_defined_in_discarded_section = false;
1192       if (st_shndx != elfcpp::SHN_UNDEF
1193           && is_ordinary
1194           && !relobj->is_section_included(st_shndx)
1195           && !this->is_section_folded(relobj, st_shndx))
1196         {
1197           st_shndx = elfcpp::SHN_UNDEF;
1198           is_defined_in_discarded_section = true;
1199         }
1200
1201       // In an object file, an '@' in the name separates the symbol
1202       // name from the version name.  If there are two '@' characters,
1203       // this is the default version.
1204       const char* ver = strchr(name, '@');
1205       Stringpool::Key ver_key = 0;
1206       int namelen = 0;
1207       // IS_DEFAULT_VERSION: is the version default?
1208       // IS_FORCED_LOCAL: is the symbol forced local?
1209       bool is_default_version = false;
1210       bool is_forced_local = false;
1211
1212       // FIXME: For incremental links, we don't store version information,
1213       // so we need to ignore version symbols for now.
1214       if (parameters->incremental_update() && ver != NULL)
1215         {
1216           namelen = ver - name;
1217           ver = NULL;
1218         }
1219
1220       if (ver != NULL)
1221         {
1222           // The symbol name is of the form foo@VERSION or foo@@VERSION
1223           namelen = ver - name;
1224           ++ver;
1225           if (*ver == '@')
1226             {
1227               is_default_version = true;
1228               ++ver;
1229             }
1230           ver = this->namepool_.add(ver, true, &ver_key);
1231         }
1232       // We don't want to assign a version to an undefined symbol,
1233       // even if it is listed in the version script.  FIXME: What
1234       // about a common symbol?
1235       else
1236         {
1237           namelen = strlen(name);
1238           if (!this->version_script_.empty()
1239               && st_shndx != elfcpp::SHN_UNDEF)
1240             {
1241               // The symbol name did not have a version, but the
1242               // version script may assign a version anyway.
1243               std::string version;
1244               bool is_global;
1245               if (this->version_script_.get_symbol_version(name, &version,
1246                                                            &is_global))
1247                 {
1248                   if (!is_global)
1249                     is_forced_local = true;
1250                   else if (!version.empty())
1251                     {
1252                       ver = this->namepool_.add_with_length(version.c_str(),
1253                                                             version.length(),
1254                                                             true,
1255                                                             &ver_key);
1256                       is_default_version = true;
1257                     }
1258                 }
1259             }
1260         }
1261
1262       elfcpp::Sym<size, big_endian>* psym = &sym;
1263       unsigned char symbuf[sym_size];
1264       elfcpp::Sym<size, big_endian> sym2(symbuf);
1265       if (just_symbols)
1266         {
1267           memcpy(symbuf, p, sym_size);
1268           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1269           if (orig_st_shndx != elfcpp::SHN_UNDEF
1270               && is_ordinary
1271               && relobj->e_type() == elfcpp::ET_REL)
1272             {
1273               // Symbol values in relocatable object files are section
1274               // relative.  This is normally what we want, but since here
1275               // we are converting the symbol to absolute we need to add
1276               // the section address.  The section address in an object
1277               // file is normally zero, but people can use a linker
1278               // script to change it.
1279               sw.put_st_value(sym.get_st_value()
1280                               + relobj->section_address(orig_st_shndx));
1281             }
1282           st_shndx = elfcpp::SHN_ABS;
1283           is_ordinary = false;
1284           psym = &sym2;
1285         }
1286
1287       // Fix up visibility if object has no-export set.
1288       if (relobj->no_export()
1289           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1290         {
1291           // We may have copied symbol already above.
1292           if (psym != &sym2)
1293             {
1294               memcpy(symbuf, p, sym_size);
1295               psym = &sym2;
1296             }
1297
1298           elfcpp::STV visibility = sym2.get_st_visibility();
1299           if (visibility == elfcpp::STV_DEFAULT
1300               || visibility == elfcpp::STV_PROTECTED)
1301             {
1302               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1303               unsigned char nonvis = sym2.get_st_nonvis();
1304               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1305             }
1306         }
1307
1308       Stringpool::Key name_key;
1309       name = this->namepool_.add_with_length(name, namelen, true,
1310                                              &name_key);
1311
1312       Sized_symbol<size>* res;
1313       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1314                                   is_default_version, *psym, st_shndx,
1315                                   is_ordinary, orig_st_shndx);
1316
1317       if (is_forced_local)
1318         this->force_local(res);
1319
1320       // Do not treat this symbol as garbage if this symbol will be
1321       // exported to the dynamic symbol table.  This is true when
1322       // building a shared library or using --export-dynamic and
1323       // the symbol is externally visible.
1324       if (parameters->options().gc_sections()
1325           && res->is_externally_visible()
1326           && !res->is_from_dynobj()
1327           && (parameters->options().shared()
1328               || parameters->options().export_dynamic()
1329               || parameters->options().in_dynamic_list(res->name())))
1330         this->gc_mark_symbol(res);
1331
1332       if (is_defined_in_discarded_section)
1333         res->set_is_defined_in_discarded_section();
1334
1335       (*sympointers)[i] = res;
1336     }
1337 }
1338
1339 // Add a symbol from a plugin-claimed file.
1340
1341 template<int size, bool big_endian>
1342 Symbol*
1343 Symbol_table::add_from_pluginobj(
1344     Sized_pluginobj<size, big_endian>* obj,
1345     const char* name,
1346     const char* ver,
1347     elfcpp::Sym<size, big_endian>* sym)
1348 {
1349   unsigned int st_shndx = sym->get_st_shndx();
1350   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1351
1352   Stringpool::Key ver_key = 0;
1353   bool is_default_version = false;
1354   bool is_forced_local = false;
1355
1356   if (ver != NULL)
1357     {
1358       ver = this->namepool_.add(ver, true, &ver_key);
1359     }
1360   // We don't want to assign a version to an undefined symbol,
1361   // even if it is listed in the version script.  FIXME: What
1362   // about a common symbol?
1363   else
1364     {
1365       if (!this->version_script_.empty()
1366           && st_shndx != elfcpp::SHN_UNDEF)
1367         {
1368           // The symbol name did not have a version, but the
1369           // version script may assign a version anyway.
1370           std::string version;
1371           bool is_global;
1372           if (this->version_script_.get_symbol_version(name, &version,
1373                                                        &is_global))
1374             {
1375               if (!is_global)
1376                 is_forced_local = true;
1377               else if (!version.empty())
1378                 {
1379                   ver = this->namepool_.add_with_length(version.c_str(),
1380                                                         version.length(),
1381                                                         true,
1382                                                         &ver_key);
1383                   is_default_version = true;
1384                 }
1385             }
1386         }
1387     }
1388
1389   Stringpool::Key name_key;
1390   name = this->namepool_.add(name, true, &name_key);
1391
1392   Sized_symbol<size>* res;
1393   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1394                               is_default_version, *sym, st_shndx,
1395                               is_ordinary, st_shndx);
1396
1397   if (is_forced_local)
1398     this->force_local(res);
1399
1400   return res;
1401 }
1402
1403 // Add all the symbols in a dynamic object to the hash table.
1404
1405 template<int size, bool big_endian>
1406 void
1407 Symbol_table::add_from_dynobj(
1408     Sized_dynobj<size, big_endian>* dynobj,
1409     const unsigned char* syms,
1410     size_t count,
1411     const char* sym_names,
1412     size_t sym_name_size,
1413     const unsigned char* versym,
1414     size_t versym_size,
1415     const std::vector<const char*>* version_map,
1416     typename Sized_relobj_file<size, big_endian>::Symbols* sympointers,
1417     size_t* defined)
1418 {
1419   *defined = 0;
1420
1421   gold_assert(size == parameters->target().get_size());
1422
1423   if (dynobj->just_symbols())
1424     {
1425       gold_error(_("--just-symbols does not make sense with a shared object"));
1426       return;
1427     }
1428
1429   // FIXME: For incremental links, we don't store version information,
1430   // so we need to ignore version symbols for now.
1431   if (parameters->incremental_update())
1432     versym = NULL;
1433
1434   if (versym != NULL && versym_size / 2 < count)
1435     {
1436       dynobj->error(_("too few symbol versions"));
1437       return;
1438     }
1439
1440   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1441
1442   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1443   // weak aliases.  This is necessary because if the dynamic object
1444   // provides the same variable under two names, one of which is a
1445   // weak definition, and the regular object refers to the weak
1446   // definition, we have to put both the weak definition and the
1447   // strong definition into the dynamic symbol table.  Given a weak
1448   // definition, the only way that we can find the corresponding
1449   // strong definition, if any, is to search the symbol table.
1450   std::vector<Sized_symbol<size>*> object_symbols;
1451
1452   const unsigned char* p = syms;
1453   const unsigned char* vs = versym;
1454   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1455     {
1456       elfcpp::Sym<size, big_endian> sym(p);
1457
1458       if (sympointers != NULL)
1459         (*sympointers)[i] = NULL;
1460
1461       // Ignore symbols with local binding or that have
1462       // internal or hidden visibility.
1463       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1464           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1465           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1466         continue;
1467
1468       // A protected symbol in a shared library must be treated as a
1469       // normal symbol when viewed from outside the shared library.
1470       // Implement this by overriding the visibility here.
1471       elfcpp::Sym<size, big_endian>* psym = &sym;
1472       unsigned char symbuf[sym_size];
1473       elfcpp::Sym<size, big_endian> sym2(symbuf);
1474       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1475         {
1476           memcpy(symbuf, p, sym_size);
1477           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1478           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1479           psym = &sym2;
1480         }
1481
1482       unsigned int st_name = psym->get_st_name();
1483       if (st_name >= sym_name_size)
1484         {
1485           dynobj->error(_("bad symbol name offset %u at %zu"),
1486                         st_name, i);
1487           continue;
1488         }
1489
1490       const char* name = sym_names + st_name;
1491
1492       bool is_ordinary;
1493       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1494                                                        &is_ordinary);
1495
1496       if (st_shndx != elfcpp::SHN_UNDEF)
1497         ++*defined;
1498
1499       Sized_symbol<size>* res;
1500
1501       if (versym == NULL)
1502         {
1503           Stringpool::Key name_key;
1504           name = this->namepool_.add(name, true, &name_key);
1505           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1506                                       false, *psym, st_shndx, is_ordinary,
1507                                       st_shndx);
1508         }
1509       else
1510         {
1511           // Read the version information.
1512
1513           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1514
1515           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1516           v &= elfcpp::VERSYM_VERSION;
1517
1518           // The Sun documentation says that V can be VER_NDX_LOCAL,
1519           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1520           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1521           // The old GNU linker will happily generate VER_NDX_LOCAL
1522           // for an undefined symbol.  I don't know what the Sun
1523           // linker will generate.
1524
1525           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1526               && st_shndx != elfcpp::SHN_UNDEF)
1527             {
1528               // This symbol should not be visible outside the object.
1529               continue;
1530             }
1531
1532           // At this point we are definitely going to add this symbol.
1533           Stringpool::Key name_key;
1534           name = this->namepool_.add(name, true, &name_key);
1535
1536           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1537               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1538             {
1539               // This symbol does not have a version.
1540               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1541                                           false, *psym, st_shndx, is_ordinary,
1542                                           st_shndx);
1543             }
1544           else
1545             {
1546               if (v >= version_map->size())
1547                 {
1548                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1549                                 i, v);
1550                   continue;
1551                 }
1552
1553               const char* version = (*version_map)[v];
1554               if (version == NULL)
1555                 {
1556                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1557                                 i, v);
1558                   continue;
1559                 }
1560
1561               Stringpool::Key version_key;
1562               version = this->namepool_.add(version, true, &version_key);
1563
1564               // If this is an absolute symbol, and the version name
1565               // and symbol name are the same, then this is the
1566               // version definition symbol.  These symbols exist to
1567               // support using -u to pull in particular versions.  We
1568               // do not want to record a version for them.
1569               if (st_shndx == elfcpp::SHN_ABS
1570                   && !is_ordinary
1571                   && name_key == version_key)
1572                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1573                                             false, *psym, st_shndx, is_ordinary,
1574                                             st_shndx);
1575               else
1576                 {
1577                   const bool is_default_version =
1578                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1579                   res = this->add_from_object(dynobj, name, name_key, version,
1580                                               version_key, is_default_version,
1581                                               *psym, st_shndx,
1582                                               is_ordinary, st_shndx);
1583                 }
1584             }
1585         }
1586
1587       // Note that it is possible that RES was overridden by an
1588       // earlier object, in which case it can't be aliased here.
1589       if (st_shndx != elfcpp::SHN_UNDEF
1590           && is_ordinary
1591           && psym->get_st_type() == elfcpp::STT_OBJECT
1592           && res->source() == Symbol::FROM_OBJECT
1593           && res->object() == dynobj)
1594         object_symbols.push_back(res);
1595
1596       if (sympointers != NULL)
1597         (*sympointers)[i] = res;
1598     }
1599
1600   this->record_weak_aliases(&object_symbols);
1601 }
1602
1603 // Add a symbol from a incremental object file.
1604
1605 template<int size, bool big_endian>
1606 Sized_symbol<size>*
1607 Symbol_table::add_from_incrobj(
1608     Object* obj,
1609     const char* name,
1610     const char* ver,
1611     elfcpp::Sym<size, big_endian>* sym)
1612 {
1613   unsigned int st_shndx = sym->get_st_shndx();
1614   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1615
1616   Stringpool::Key ver_key = 0;
1617   bool is_default_version = false;
1618   bool is_forced_local = false;
1619
1620   Stringpool::Key name_key;
1621   name = this->namepool_.add(name, true, &name_key);
1622
1623   Sized_symbol<size>* res;
1624   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1625                               is_default_version, *sym, st_shndx,
1626                               is_ordinary, st_shndx);
1627
1628   if (is_forced_local)
1629     this->force_local(res);
1630
1631   return res;
1632 }
1633
1634 // This is used to sort weak aliases.  We sort them first by section
1635 // index, then by offset, then by weak ahead of strong.
1636
1637 template<int size>
1638 class Weak_alias_sorter
1639 {
1640  public:
1641   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1642 };
1643
1644 template<int size>
1645 bool
1646 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1647                                     const Sized_symbol<size>* s2) const
1648 {
1649   bool is_ordinary;
1650   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1651   gold_assert(is_ordinary);
1652   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1653   gold_assert(is_ordinary);
1654   if (s1_shndx != s2_shndx)
1655     return s1_shndx < s2_shndx;
1656
1657   if (s1->value() != s2->value())
1658     return s1->value() < s2->value();
1659   if (s1->binding() != s2->binding())
1660     {
1661       if (s1->binding() == elfcpp::STB_WEAK)
1662         return true;
1663       if (s2->binding() == elfcpp::STB_WEAK)
1664         return false;
1665     }
1666   return std::string(s1->name()) < std::string(s2->name());
1667 }
1668
1669 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1670 // for any weak aliases, and record them so that if we add the weak
1671 // alias to the dynamic symbol table, we also add the corresponding
1672 // strong symbol.
1673
1674 template<int size>
1675 void
1676 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1677 {
1678   // Sort the vector by section index, then by offset, then by weak
1679   // ahead of strong.
1680   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1681
1682   // Walk through the vector.  For each weak definition, record
1683   // aliases.
1684   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1685          symbols->begin();
1686        p != symbols->end();
1687        ++p)
1688     {
1689       if ((*p)->binding() != elfcpp::STB_WEAK)
1690         continue;
1691
1692       // Build a circular list of weak aliases.  Each symbol points to
1693       // the next one in the circular list.
1694
1695       Sized_symbol<size>* from_sym = *p;
1696       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1697       for (q = p + 1; q != symbols->end(); ++q)
1698         {
1699           bool dummy;
1700           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1701               || (*q)->value() != from_sym->value())
1702             break;
1703
1704           this->weak_aliases_[from_sym] = *q;
1705           from_sym->set_has_alias();
1706           from_sym = *q;
1707         }
1708
1709       if (from_sym != *p)
1710         {
1711           this->weak_aliases_[from_sym] = *p;
1712           from_sym->set_has_alias();
1713         }
1714
1715       p = q - 1;
1716     }
1717 }
1718
1719 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1720 // true, then only create the symbol if there is a reference to it.
1721 // If this does not return NULL, it sets *POLDSYM to the existing
1722 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1723 // resolve the newly created symbol to the old one.  This
1724 // canonicalizes *PNAME and *PVERSION.
1725
1726 template<int size, bool big_endian>
1727 Sized_symbol<size>*
1728 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1729                                     bool only_if_ref,
1730                                     Sized_symbol<size>** poldsym,
1731                                     bool* resolve_oldsym)
1732 {
1733   *resolve_oldsym = false;
1734   *poldsym = NULL;
1735
1736   // If the caller didn't give us a version, see if we get one from
1737   // the version script.
1738   std::string v;
1739   bool is_default_version = false;
1740   if (*pversion == NULL)
1741     {
1742       bool is_global;
1743       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1744         {
1745           if (is_global && !v.empty())
1746             {
1747               *pversion = v.c_str();
1748               // If we get the version from a version script, then we
1749               // are also the default version.
1750               is_default_version = true;
1751             }
1752         }
1753     }
1754
1755   Symbol* oldsym;
1756   Sized_symbol<size>* sym;
1757
1758   bool add_to_table = false;
1759   typename Symbol_table_type::iterator add_loc = this->table_.end();
1760   bool add_def_to_table = false;
1761   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1762
1763   if (only_if_ref)
1764     {
1765       oldsym = this->lookup(*pname, *pversion);
1766       if (oldsym == NULL && is_default_version)
1767         oldsym = this->lookup(*pname, NULL);
1768       if (oldsym == NULL || !oldsym->is_undefined())
1769         return NULL;
1770
1771       *pname = oldsym->name();
1772       if (is_default_version)
1773         *pversion = this->namepool_.add(*pversion, true, NULL);
1774       else
1775         *pversion = oldsym->version();
1776     }
1777   else
1778     {
1779       // Canonicalize NAME and VERSION.
1780       Stringpool::Key name_key;
1781       *pname = this->namepool_.add(*pname, true, &name_key);
1782
1783       Stringpool::Key version_key = 0;
1784       if (*pversion != NULL)
1785         *pversion = this->namepool_.add(*pversion, true, &version_key);
1786
1787       Symbol* const snull = NULL;
1788       std::pair<typename Symbol_table_type::iterator, bool> ins =
1789         this->table_.insert(std::make_pair(std::make_pair(name_key,
1790                                                           version_key),
1791                                            snull));
1792
1793       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1794         std::make_pair(this->table_.end(), false);
1795       if (is_default_version)
1796         {
1797           const Stringpool::Key vnull = 0;
1798           insdefault =
1799             this->table_.insert(std::make_pair(std::make_pair(name_key,
1800                                                               vnull),
1801                                                snull));
1802         }
1803
1804       if (!ins.second)
1805         {
1806           // We already have a symbol table entry for NAME/VERSION.
1807           oldsym = ins.first->second;
1808           gold_assert(oldsym != NULL);
1809
1810           if (is_default_version)
1811             {
1812               Sized_symbol<size>* soldsym =
1813                 this->get_sized_symbol<size>(oldsym);
1814               this->define_default_version<size, big_endian>(soldsym,
1815                                                              insdefault.second,
1816                                                              insdefault.first);
1817             }
1818         }
1819       else
1820         {
1821           // We haven't seen this symbol before.
1822           gold_assert(ins.first->second == NULL);
1823
1824           add_to_table = true;
1825           add_loc = ins.first;
1826
1827           if (is_default_version && !insdefault.second)
1828             {
1829               // We are adding NAME/VERSION, and it is the default
1830               // version.  We already have an entry for NAME/NULL.
1831               oldsym = insdefault.first->second;
1832               *resolve_oldsym = true;
1833             }
1834           else
1835             {
1836               oldsym = NULL;
1837
1838               if (is_default_version)
1839                 {
1840                   add_def_to_table = true;
1841                   add_def_loc = insdefault.first;
1842                 }
1843             }
1844         }
1845     }
1846
1847   const Target& target = parameters->target();
1848   if (!target.has_make_symbol())
1849     sym = new Sized_symbol<size>();
1850   else
1851     {
1852       Sized_target<size, big_endian>* sized_target =
1853         parameters->sized_target<size, big_endian>();
1854       sym = sized_target->make_symbol();
1855       if (sym == NULL)
1856         return NULL;
1857     }
1858
1859   if (add_to_table)
1860     add_loc->second = sym;
1861   else
1862     gold_assert(oldsym != NULL);
1863
1864   if (add_def_to_table)
1865     add_def_loc->second = sym;
1866
1867   *poldsym = this->get_sized_symbol<size>(oldsym);
1868
1869   return sym;
1870 }
1871
1872 // Define a symbol based on an Output_data.
1873
1874 Symbol*
1875 Symbol_table::define_in_output_data(const char* name,
1876                                     const char* version,
1877                                     Defined defined,
1878                                     Output_data* od,
1879                                     uint64_t value,
1880                                     uint64_t symsize,
1881                                     elfcpp::STT type,
1882                                     elfcpp::STB binding,
1883                                     elfcpp::STV visibility,
1884                                     unsigned char nonvis,
1885                                     bool offset_is_from_end,
1886                                     bool only_if_ref)
1887 {
1888   if (parameters->target().get_size() == 32)
1889     {
1890 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1891       return this->do_define_in_output_data<32>(name, version, defined, od,
1892                                                 value, symsize, type, binding,
1893                                                 visibility, nonvis,
1894                                                 offset_is_from_end,
1895                                                 only_if_ref);
1896 #else
1897       gold_unreachable();
1898 #endif
1899     }
1900   else if (parameters->target().get_size() == 64)
1901     {
1902 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1903       return this->do_define_in_output_data<64>(name, version, defined, od,
1904                                                 value, symsize, type, binding,
1905                                                 visibility, nonvis,
1906                                                 offset_is_from_end,
1907                                                 only_if_ref);
1908 #else
1909       gold_unreachable();
1910 #endif
1911     }
1912   else
1913     gold_unreachable();
1914 }
1915
1916 // Define a symbol in an Output_data, sized version.
1917
1918 template<int size>
1919 Sized_symbol<size>*
1920 Symbol_table::do_define_in_output_data(
1921     const char* name,
1922     const char* version,
1923     Defined defined,
1924     Output_data* od,
1925     typename elfcpp::Elf_types<size>::Elf_Addr value,
1926     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1927     elfcpp::STT type,
1928     elfcpp::STB binding,
1929     elfcpp::STV visibility,
1930     unsigned char nonvis,
1931     bool offset_is_from_end,
1932     bool only_if_ref)
1933 {
1934   Sized_symbol<size>* sym;
1935   Sized_symbol<size>* oldsym;
1936   bool resolve_oldsym;
1937
1938   if (parameters->target().is_big_endian())
1939     {
1940 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1941       sym = this->define_special_symbol<size, true>(&name, &version,
1942                                                     only_if_ref, &oldsym,
1943                                                     &resolve_oldsym);
1944 #else
1945       gold_unreachable();
1946 #endif
1947     }
1948   else
1949     {
1950 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1951       sym = this->define_special_symbol<size, false>(&name, &version,
1952                                                      only_if_ref, &oldsym,
1953                                                      &resolve_oldsym);
1954 #else
1955       gold_unreachable();
1956 #endif
1957     }
1958
1959   if (sym == NULL)
1960     return NULL;
1961
1962   sym->init_output_data(name, version, od, value, symsize, type, binding,
1963                         visibility, nonvis, offset_is_from_end,
1964                         defined == PREDEFINED);
1965
1966   if (oldsym == NULL)
1967     {
1968       if (binding == elfcpp::STB_LOCAL
1969           || this->version_script_.symbol_is_local(name))
1970         this->force_local(sym);
1971       else if (version != NULL)
1972         sym->set_is_default();
1973       return sym;
1974     }
1975
1976   if (Symbol_table::should_override_with_special(oldsym, type, defined))
1977     this->override_with_special(oldsym, sym);
1978
1979   if (resolve_oldsym)
1980     return sym;
1981   else
1982     {
1983       if (binding == elfcpp::STB_LOCAL
1984           || this->version_script_.symbol_is_local(name))
1985         this->force_local(oldsym);
1986       delete sym;
1987       return oldsym;
1988     }
1989 }
1990
1991 // Define a symbol based on an Output_segment.
1992
1993 Symbol*
1994 Symbol_table::define_in_output_segment(const char* name,
1995                                        const char* version,
1996                                        Defined defined,
1997                                        Output_segment* os,
1998                                        uint64_t value,
1999                                        uint64_t symsize,
2000                                        elfcpp::STT type,
2001                                        elfcpp::STB binding,
2002                                        elfcpp::STV visibility,
2003                                        unsigned char nonvis,
2004                                        Symbol::Segment_offset_base offset_base,
2005                                        bool only_if_ref)
2006 {
2007   if (parameters->target().get_size() == 32)
2008     {
2009 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2010       return this->do_define_in_output_segment<32>(name, version, defined, os,
2011                                                    value, symsize, type,
2012                                                    binding, visibility, nonvis,
2013                                                    offset_base, only_if_ref);
2014 #else
2015       gold_unreachable();
2016 #endif
2017     }
2018   else if (parameters->target().get_size() == 64)
2019     {
2020 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2021       return this->do_define_in_output_segment<64>(name, version, defined, os,
2022                                                    value, symsize, type,
2023                                                    binding, visibility, nonvis,
2024                                                    offset_base, only_if_ref);
2025 #else
2026       gold_unreachable();
2027 #endif
2028     }
2029   else
2030     gold_unreachable();
2031 }
2032
2033 // Define a symbol in an Output_segment, sized version.
2034
2035 template<int size>
2036 Sized_symbol<size>*
2037 Symbol_table::do_define_in_output_segment(
2038     const char* name,
2039     const char* version,
2040     Defined defined,
2041     Output_segment* os,
2042     typename elfcpp::Elf_types<size>::Elf_Addr value,
2043     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
2044     elfcpp::STT type,
2045     elfcpp::STB binding,
2046     elfcpp::STV visibility,
2047     unsigned char nonvis,
2048     Symbol::Segment_offset_base offset_base,
2049     bool only_if_ref)
2050 {
2051   Sized_symbol<size>* sym;
2052   Sized_symbol<size>* oldsym;
2053   bool resolve_oldsym;
2054
2055   if (parameters->target().is_big_endian())
2056     {
2057 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2058       sym = this->define_special_symbol<size, true>(&name, &version,
2059                                                     only_if_ref, &oldsym,
2060                                                     &resolve_oldsym);
2061 #else
2062       gold_unreachable();
2063 #endif
2064     }
2065   else
2066     {
2067 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2068       sym = this->define_special_symbol<size, false>(&name, &version,
2069                                                      only_if_ref, &oldsym,
2070                                                      &resolve_oldsym);
2071 #else
2072       gold_unreachable();
2073 #endif
2074     }
2075
2076   if (sym == NULL)
2077     return NULL;
2078
2079   sym->init_output_segment(name, version, os, value, symsize, type, binding,
2080                            visibility, nonvis, offset_base,
2081                            defined == PREDEFINED);
2082
2083   if (oldsym == NULL)
2084     {
2085       if (binding == elfcpp::STB_LOCAL
2086           || this->version_script_.symbol_is_local(name))
2087         this->force_local(sym);
2088       else if (version != NULL)
2089         sym->set_is_default();
2090       return sym;
2091     }
2092
2093   if (Symbol_table::should_override_with_special(oldsym, type, defined))
2094     this->override_with_special(oldsym, sym);
2095
2096   if (resolve_oldsym)
2097     return sym;
2098   else
2099     {
2100       if (binding == elfcpp::STB_LOCAL
2101           || this->version_script_.symbol_is_local(name))
2102         this->force_local(oldsym);
2103       delete sym;
2104       return oldsym;
2105     }
2106 }
2107
2108 // Define a special symbol with a constant value.  It is a multiple
2109 // definition error if this symbol is already defined.
2110
2111 Symbol*
2112 Symbol_table::define_as_constant(const char* name,
2113                                  const char* version,
2114                                  Defined defined,
2115                                  uint64_t value,
2116                                  uint64_t symsize,
2117                                  elfcpp::STT type,
2118                                  elfcpp::STB binding,
2119                                  elfcpp::STV visibility,
2120                                  unsigned char nonvis,
2121                                  bool only_if_ref,
2122                                  bool force_override)
2123 {
2124   if (parameters->target().get_size() == 32)
2125     {
2126 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2127       return this->do_define_as_constant<32>(name, version, defined, value,
2128                                              symsize, type, binding,
2129                                              visibility, nonvis, only_if_ref,
2130                                              force_override);
2131 #else
2132       gold_unreachable();
2133 #endif
2134     }
2135   else if (parameters->target().get_size() == 64)
2136     {
2137 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2138       return this->do_define_as_constant<64>(name, version, defined, value,
2139                                              symsize, type, binding,
2140                                              visibility, nonvis, only_if_ref,
2141                                              force_override);
2142 #else
2143       gold_unreachable();
2144 #endif
2145     }
2146   else
2147     gold_unreachable();
2148 }
2149
2150 // Define a symbol as a constant, sized version.
2151
2152 template<int size>
2153 Sized_symbol<size>*
2154 Symbol_table::do_define_as_constant(
2155     const char* name,
2156     const char* version,
2157     Defined defined,
2158     typename elfcpp::Elf_types<size>::Elf_Addr value,
2159     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
2160     elfcpp::STT type,
2161     elfcpp::STB binding,
2162     elfcpp::STV visibility,
2163     unsigned char nonvis,
2164     bool only_if_ref,
2165     bool force_override)
2166 {
2167   Sized_symbol<size>* sym;
2168   Sized_symbol<size>* oldsym;
2169   bool resolve_oldsym;
2170
2171   if (parameters->target().is_big_endian())
2172     {
2173 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2174       sym = this->define_special_symbol<size, true>(&name, &version,
2175                                                     only_if_ref, &oldsym,
2176                                                     &resolve_oldsym);
2177 #else
2178       gold_unreachable();
2179 #endif
2180     }
2181   else
2182     {
2183 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2184       sym = this->define_special_symbol<size, false>(&name, &version,
2185                                                      only_if_ref, &oldsym,
2186                                                      &resolve_oldsym);
2187 #else
2188       gold_unreachable();
2189 #endif
2190     }
2191
2192   if (sym == NULL)
2193     return NULL;
2194
2195   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2196                      nonvis, defined == PREDEFINED);
2197
2198   if (oldsym == NULL)
2199     {
2200       // Version symbols are absolute symbols with name == version.
2201       // We don't want to force them to be local.
2202       if ((version == NULL
2203            || name != version
2204            || value != 0)
2205           && (binding == elfcpp::STB_LOCAL
2206               || this->version_script_.symbol_is_local(name)))
2207         this->force_local(sym);
2208       else if (version != NULL
2209                && (name != version || value != 0))
2210         sym->set_is_default();
2211       return sym;
2212     }
2213
2214   if (force_override
2215       || Symbol_table::should_override_with_special(oldsym, type, defined))
2216     this->override_with_special(oldsym, sym);
2217
2218   if (resolve_oldsym)
2219     return sym;
2220   else
2221     {
2222       if (binding == elfcpp::STB_LOCAL
2223           || this->version_script_.symbol_is_local(name))
2224         this->force_local(oldsym);
2225       delete sym;
2226       return oldsym;
2227     }
2228 }
2229
2230 // Define a set of symbols in output sections.
2231
2232 void
2233 Symbol_table::define_symbols(const Layout* layout, int count,
2234                              const Define_symbol_in_section* p,
2235                              bool only_if_ref)
2236 {
2237   for (int i = 0; i < count; ++i, ++p)
2238     {
2239       Output_section* os = layout->find_output_section(p->output_section);
2240       if (os != NULL)
2241         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2242                                     p->size, p->type, p->binding,
2243                                     p->visibility, p->nonvis,
2244                                     p->offset_is_from_end,
2245                                     only_if_ref || p->only_if_ref);
2246       else
2247         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2248                                  p->type, p->binding, p->visibility, p->nonvis,
2249                                  only_if_ref || p->only_if_ref,
2250                                  false);
2251     }
2252 }
2253
2254 // Define a set of symbols in output segments.
2255
2256 void
2257 Symbol_table::define_symbols(const Layout* layout, int count,
2258                              const Define_symbol_in_segment* p,
2259                              bool only_if_ref)
2260 {
2261   for (int i = 0; i < count; ++i, ++p)
2262     {
2263       Output_segment* os = layout->find_output_segment(p->segment_type,
2264                                                        p->segment_flags_set,
2265                                                        p->segment_flags_clear);
2266       if (os != NULL)
2267         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2268                                        p->size, p->type, p->binding,
2269                                        p->visibility, p->nonvis,
2270                                        p->offset_base,
2271                                        only_if_ref || p->only_if_ref);
2272       else
2273         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2274                                  p->type, p->binding, p->visibility, p->nonvis,
2275                                  only_if_ref || p->only_if_ref,
2276                                  false);
2277     }
2278 }
2279
2280 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2281 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2282 // the offset within POSD.
2283
2284 template<int size>
2285 void
2286 Symbol_table::define_with_copy_reloc(
2287     Sized_symbol<size>* csym,
2288     Output_data* posd,
2289     typename elfcpp::Elf_types<size>::Elf_Addr value)
2290 {
2291   gold_assert(csym->is_from_dynobj());
2292   gold_assert(!csym->is_copied_from_dynobj());
2293   Object* object = csym->object();
2294   gold_assert(object->is_dynamic());
2295   Dynobj* dynobj = static_cast<Dynobj*>(object);
2296
2297   // Our copied variable has to override any variable in a shared
2298   // library.
2299   elfcpp::STB binding = csym->binding();
2300   if (binding == elfcpp::STB_WEAK)
2301     binding = elfcpp::STB_GLOBAL;
2302
2303   this->define_in_output_data(csym->name(), csym->version(), COPY,
2304                               posd, value, csym->symsize(),
2305                               csym->type(), binding,
2306                               csym->visibility(), csym->nonvis(),
2307                               false, false);
2308
2309   csym->set_is_copied_from_dynobj();
2310   csym->set_needs_dynsym_entry();
2311
2312   this->copied_symbol_dynobjs_[csym] = dynobj;
2313
2314   // We have now defined all aliases, but we have not entered them all
2315   // in the copied_symbol_dynobjs_ map.
2316   if (csym->has_alias())
2317     {
2318       Symbol* sym = csym;
2319       while (true)
2320         {
2321           sym = this->weak_aliases_[sym];
2322           if (sym == csym)
2323             break;
2324           gold_assert(sym->output_data() == posd);
2325
2326           sym->set_is_copied_from_dynobj();
2327           this->copied_symbol_dynobjs_[sym] = dynobj;
2328         }
2329     }
2330 }
2331
2332 // SYM is defined using a COPY reloc.  Return the dynamic object where
2333 // the original definition was found.
2334
2335 Dynobj*
2336 Symbol_table::get_copy_source(const Symbol* sym) const
2337 {
2338   gold_assert(sym->is_copied_from_dynobj());
2339   Copied_symbol_dynobjs::const_iterator p =
2340     this->copied_symbol_dynobjs_.find(sym);
2341   gold_assert(p != this->copied_symbol_dynobjs_.end());
2342   return p->second;
2343 }
2344
2345 // Add any undefined symbols named on the command line.
2346
2347 void
2348 Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
2349 {
2350   if (parameters->options().any_undefined()
2351       || layout->script_options()->any_unreferenced())
2352     {
2353       if (parameters->target().get_size() == 32)
2354         {
2355 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2356           this->do_add_undefined_symbols_from_command_line<32>(layout);
2357 #else
2358           gold_unreachable();
2359 #endif
2360         }
2361       else if (parameters->target().get_size() == 64)
2362         {
2363 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2364           this->do_add_undefined_symbols_from_command_line<64>(layout);
2365 #else
2366           gold_unreachable();
2367 #endif
2368         }
2369       else
2370         gold_unreachable();
2371     }
2372 }
2373
2374 template<int size>
2375 void
2376 Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
2377 {
2378   for (options::String_set::const_iterator p =
2379          parameters->options().undefined_begin();
2380        p != parameters->options().undefined_end();
2381        ++p)
2382     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2383
2384   for (options::String_set::const_iterator p =
2385          parameters->options().export_dynamic_symbol_begin();
2386        p != parameters->options().export_dynamic_symbol_end();
2387        ++p)
2388     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2389
2390   for (Script_options::referenced_const_iterator p =
2391          layout->script_options()->referenced_begin();
2392        p != layout->script_options()->referenced_end();
2393        ++p)
2394     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2395 }
2396
2397 template<int size>
2398 void
2399 Symbol_table::add_undefined_symbol_from_command_line(const char* name)
2400 {
2401   if (this->lookup(name) != NULL)
2402     return;
2403
2404   const char* version = NULL;
2405
2406   Sized_symbol<size>* sym;
2407   Sized_symbol<size>* oldsym;
2408   bool resolve_oldsym;
2409   if (parameters->target().is_big_endian())
2410     {
2411 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2412       sym = this->define_special_symbol<size, true>(&name, &version,
2413                                                     false, &oldsym,
2414                                                     &resolve_oldsym);
2415 #else
2416       gold_unreachable();
2417 #endif
2418     }
2419   else
2420     {
2421 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2422       sym = this->define_special_symbol<size, false>(&name, &version,
2423                                                      false, &oldsym,
2424                                                      &resolve_oldsym);
2425 #else
2426       gold_unreachable();
2427 #endif
2428     }
2429
2430   gold_assert(oldsym == NULL);
2431
2432   sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2433                       elfcpp::STV_DEFAULT, 0);
2434   ++this->saw_undefined_;
2435 }
2436
2437 // Set the dynamic symbol indexes.  INDEX is the index of the first
2438 // global dynamic symbol.  Pointers to the symbols are stored into the
2439 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2440 // updated dynamic symbol index.
2441
2442 unsigned int
2443 Symbol_table::set_dynsym_indexes(unsigned int index,
2444                                  std::vector<Symbol*>* syms,
2445                                  Stringpool* dynpool,
2446                                  Versions* versions)
2447 {
2448   std::vector<Symbol*> as_needed_sym;
2449
2450   // Allow a target to set dynsym indexes.
2451   if (parameters->target().has_custom_set_dynsym_indexes())
2452     {
2453       std::vector<Symbol*> dyn_symbols;
2454       for (Symbol_table_type::iterator p = this->table_.begin();
2455            p != this->table_.end();
2456            ++p)
2457         {
2458           Symbol* sym = p->second;
2459           if (!sym->should_add_dynsym_entry(this))
2460             sym->set_dynsym_index(-1U);
2461           else
2462             dyn_symbols.push_back(sym);
2463         }
2464
2465       return parameters->target().set_dynsym_indexes(&dyn_symbols, index, syms,
2466                                                      dynpool, versions, this);
2467     }
2468
2469   for (Symbol_table_type::iterator p = this->table_.begin();
2470        p != this->table_.end();
2471        ++p)
2472     {
2473       Symbol* sym = p->second;
2474
2475       // Note that SYM may already have a dynamic symbol index, since
2476       // some symbols appear more than once in the symbol table, with
2477       // and without a version.
2478
2479       if (!sym->should_add_dynsym_entry(this))
2480         sym->set_dynsym_index(-1U);
2481       else if (!sym->has_dynsym_index())
2482         {
2483           sym->set_dynsym_index(index);
2484           ++index;
2485           syms->push_back(sym);
2486           dynpool->add(sym->name(), false, NULL);
2487
2488           // If the symbol is defined in a dynamic object and is
2489           // referenced strongly in a regular object, then mark the
2490           // dynamic object as needed.  This is used to implement
2491           // --as-needed.
2492           if (sym->is_from_dynobj()
2493               && sym->in_reg()
2494               && !sym->is_undef_binding_weak())
2495             sym->object()->set_is_needed();
2496
2497           // Record any version information, except those from
2498           // as-needed libraries not seen to be needed.  Note that the
2499           // is_needed state for such libraries can change in this loop.
2500           if (sym->version() != NULL)
2501             {
2502               if (!sym->is_from_dynobj()
2503                   || !sym->object()->as_needed()
2504                   || sym->object()->is_needed())
2505                 versions->record_version(this, dynpool, sym);
2506               else
2507                 as_needed_sym.push_back(sym);
2508             }
2509         }
2510     }
2511
2512   // Process version information for symbols from as-needed libraries.
2513   for (std::vector<Symbol*>::iterator p = as_needed_sym.begin();
2514        p != as_needed_sym.end();
2515        ++p)
2516     {
2517       Symbol* sym = *p;
2518
2519       if (sym->object()->is_needed())
2520         versions->record_version(this, dynpool, sym);
2521       else
2522         sym->clear_version();
2523     }
2524
2525   // Finish up the versions.  In some cases this may add new dynamic
2526   // symbols.
2527   index = versions->finalize(this, index, syms);
2528
2529   return index;
2530 }
2531
2532 // Set the final values for all the symbols.  The index of the first
2533 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2534 // file offset OFF.  Add their names to POOL.  Return the new file
2535 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2536
2537 off_t
2538 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2539                        size_t dyncount, Stringpool* pool,
2540                        unsigned int* plocal_symcount)
2541 {
2542   off_t ret;
2543
2544   gold_assert(*plocal_symcount != 0);
2545   this->first_global_index_ = *plocal_symcount;
2546
2547   this->dynamic_offset_ = dynoff;
2548   this->first_dynamic_global_index_ = dyn_global_index;
2549   this->dynamic_count_ = dyncount;
2550
2551   if (parameters->target().get_size() == 32)
2552     {
2553 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2554       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2555 #else
2556       gold_unreachable();
2557 #endif
2558     }
2559   else if (parameters->target().get_size() == 64)
2560     {
2561 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2562       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2563 #else
2564       gold_unreachable();
2565 #endif
2566     }
2567   else
2568     gold_unreachable();
2569
2570   // Now that we have the final symbol table, we can reliably note
2571   // which symbols should get warnings.
2572   this->warnings_.note_warnings(this);
2573
2574   return ret;
2575 }
2576
2577 // SYM is going into the symbol table at *PINDEX.  Add the name to
2578 // POOL, update *PINDEX and *POFF.
2579
2580 template<int size>
2581 void
2582 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2583                                   unsigned int* pindex, off_t* poff)
2584 {
2585   sym->set_symtab_index(*pindex);
2586   if (sym->version() == NULL || !parameters->options().relocatable())
2587     pool->add(sym->name(), false, NULL);
2588   else
2589     pool->add(sym->versioned_name(), true, NULL);
2590   ++*pindex;
2591   *poff += elfcpp::Elf_sizes<size>::sym_size;
2592 }
2593
2594 // Set the final value for all the symbols.  This is called after
2595 // Layout::finalize, so all the output sections have their final
2596 // address.
2597
2598 template<int size>
2599 off_t
2600 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2601                              unsigned int* plocal_symcount)
2602 {
2603   off = align_address(off, size >> 3);
2604   this->offset_ = off;
2605
2606   unsigned int index = *plocal_symcount;
2607   const unsigned int orig_index = index;
2608
2609   // First do all the symbols which have been forced to be local, as
2610   // they must appear before all global symbols.
2611   for (Forced_locals::iterator p = this->forced_locals_.begin();
2612        p != this->forced_locals_.end();
2613        ++p)
2614     {
2615       Symbol* sym = *p;
2616       gold_assert(sym->is_forced_local());
2617       if (this->sized_finalize_symbol<size>(sym))
2618         {
2619           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2620           ++*plocal_symcount;
2621         }
2622     }
2623
2624   // Now do all the remaining symbols.
2625   for (Symbol_table_type::iterator p = this->table_.begin();
2626        p != this->table_.end();
2627        ++p)
2628     {
2629       Symbol* sym = p->second;
2630       if (this->sized_finalize_symbol<size>(sym))
2631         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2632     }
2633
2634   this->output_count_ = index - orig_index;
2635
2636   return off;
2637 }
2638
2639 // Compute the final value of SYM and store status in location PSTATUS.
2640 // During relaxation, this may be called multiple times for a symbol to
2641 // compute its would-be final value in each relaxation pass.
2642
2643 template<int size>
2644 typename Sized_symbol<size>::Value_type
2645 Symbol_table::compute_final_value(
2646     const Sized_symbol<size>* sym,
2647     Compute_final_value_status* pstatus) const
2648 {
2649   typedef typename Sized_symbol<size>::Value_type Value_type;
2650   Value_type value;
2651
2652   switch (sym->source())
2653     {
2654     case Symbol::FROM_OBJECT:
2655       {
2656         bool is_ordinary;
2657         unsigned int shndx = sym->shndx(&is_ordinary);
2658
2659         if (!is_ordinary
2660             && shndx != elfcpp::SHN_ABS
2661             && !Symbol::is_common_shndx(shndx))
2662           {
2663             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2664             return 0;
2665           }
2666
2667         Object* symobj = sym->object();
2668         if (symobj->is_dynamic())
2669           {
2670             value = 0;
2671             shndx = elfcpp::SHN_UNDEF;
2672           }
2673         else if (symobj->pluginobj() != NULL)
2674           {
2675             value = 0;
2676             shndx = elfcpp::SHN_UNDEF;
2677           }
2678         else if (shndx == elfcpp::SHN_UNDEF)
2679           value = 0;
2680         else if (!is_ordinary
2681                  && (shndx == elfcpp::SHN_ABS
2682                      || Symbol::is_common_shndx(shndx)))
2683           value = sym->value();
2684         else
2685           {
2686             Relobj* relobj = static_cast<Relobj*>(symobj);
2687             Output_section* os = relobj->output_section(shndx);
2688
2689             if (this->is_section_folded(relobj, shndx))
2690               {
2691                 gold_assert(os == NULL);
2692                 // Get the os of the section it is folded onto.
2693                 Section_id folded = this->icf_->get_folded_section(relobj,
2694                                                                    shndx);
2695                 gold_assert(folded.first != NULL);
2696                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2697                 unsigned folded_shndx = folded.second;
2698
2699                 os = folded_obj->output_section(folded_shndx);
2700                 gold_assert(os != NULL);
2701
2702                 // Replace (relobj, shndx) with canonical ICF input section.
2703                 shndx = folded_shndx;
2704                 relobj = folded_obj;
2705               }
2706
2707             uint64_t secoff64 = relobj->output_section_offset(shndx);
2708             if (os == NULL)
2709               {
2710                 bool static_or_reloc = (parameters->doing_static_link() ||
2711                                         parameters->options().relocatable());
2712                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2713
2714                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2715                 return 0;
2716               }
2717
2718             if (secoff64 == -1ULL)
2719               {
2720                 // The section needs special handling (e.g., a merge section).
2721
2722                 value = os->output_address(relobj, shndx, sym->value());
2723               }
2724             else
2725               {
2726                 Value_type secoff =
2727                   convert_types<Value_type, uint64_t>(secoff64);
2728                 if (sym->type() == elfcpp::STT_TLS)
2729                   value = sym->value() + os->tls_offset() + secoff;
2730                 else
2731                   value = sym->value() + os->address() + secoff;
2732               }
2733           }
2734       }
2735       break;
2736
2737     case Symbol::IN_OUTPUT_DATA:
2738       {
2739         Output_data* od = sym->output_data();
2740         value = sym->value();
2741         if (sym->type() != elfcpp::STT_TLS)
2742           value += od->address();
2743         else
2744           {
2745             Output_section* os = od->output_section();
2746             gold_assert(os != NULL);
2747             value += os->tls_offset() + (od->address() - os->address());
2748           }
2749         if (sym->offset_is_from_end())
2750           value += od->data_size();
2751       }
2752       break;
2753
2754     case Symbol::IN_OUTPUT_SEGMENT:
2755       {
2756         Output_segment* os = sym->output_segment();
2757         value = sym->value();
2758         if (sym->type() != elfcpp::STT_TLS)
2759           value += os->vaddr();
2760         switch (sym->offset_base())
2761           {
2762           case Symbol::SEGMENT_START:
2763             break;
2764           case Symbol::SEGMENT_END:
2765             value += os->memsz();
2766             break;
2767           case Symbol::SEGMENT_BSS:
2768             value += os->filesz();
2769             break;
2770           default:
2771             gold_unreachable();
2772           }
2773       }
2774       break;
2775
2776     case Symbol::IS_CONSTANT:
2777       value = sym->value();
2778       break;
2779
2780     case Symbol::IS_UNDEFINED:
2781       value = 0;
2782       break;
2783
2784     default:
2785       gold_unreachable();
2786     }
2787
2788   *pstatus = CFVS_OK;
2789   return value;
2790 }
2791
2792 // Finalize the symbol SYM.  This returns true if the symbol should be
2793 // added to the symbol table, false otherwise.
2794
2795 template<int size>
2796 bool
2797 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2798 {
2799   typedef typename Sized_symbol<size>::Value_type Value_type;
2800
2801   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2802
2803   // The default version of a symbol may appear twice in the symbol
2804   // table.  We only need to finalize it once.
2805   if (sym->has_symtab_index())
2806     return false;
2807
2808   if (!sym->in_reg())
2809     {
2810       gold_assert(!sym->has_symtab_index());
2811       sym->set_symtab_index(-1U);
2812       gold_assert(sym->dynsym_index() == -1U);
2813       return false;
2814     }
2815
2816   // If the symbol is only present on plugin files, the plugin decided we
2817   // don't need it.
2818   if (!sym->in_real_elf())
2819     {
2820       gold_assert(!sym->has_symtab_index());
2821       sym->set_symtab_index(-1U);
2822       return false;
2823     }
2824
2825   // Compute final symbol value.
2826   Compute_final_value_status status;
2827   Value_type value = this->compute_final_value(sym, &status);
2828
2829   switch (status)
2830     {
2831     case CFVS_OK:
2832       break;
2833     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2834       {
2835         bool is_ordinary;
2836         unsigned int shndx = sym->shndx(&is_ordinary);
2837         gold_error(_("%s: unsupported symbol section 0x%x"),
2838                    sym->demangled_name().c_str(), shndx);
2839       }
2840       break;
2841     case CFVS_NO_OUTPUT_SECTION:
2842       sym->set_symtab_index(-1U);
2843       return false;
2844     default:
2845       gold_unreachable();
2846     }
2847
2848   sym->set_value(value);
2849
2850   if (parameters->options().strip_all()
2851       || !parameters->options().should_retain_symbol(sym->name()))
2852     {
2853       sym->set_symtab_index(-1U);
2854       return false;
2855     }
2856
2857   return true;
2858 }
2859
2860 // Write out the global symbols.
2861
2862 void
2863 Symbol_table::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   switch (parameters->size_and_endianness())
2870     {
2871 #ifdef HAVE_TARGET_32_LITTLE
2872     case Parameters::TARGET_32_LITTLE:
2873       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2874                                            dynsym_xindex, of);
2875       break;
2876 #endif
2877 #ifdef HAVE_TARGET_32_BIG
2878     case Parameters::TARGET_32_BIG:
2879       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2880                                           dynsym_xindex, of);
2881       break;
2882 #endif
2883 #ifdef HAVE_TARGET_64_LITTLE
2884     case Parameters::TARGET_64_LITTLE:
2885       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2886                                            dynsym_xindex, of);
2887       break;
2888 #endif
2889 #ifdef HAVE_TARGET_64_BIG
2890     case Parameters::TARGET_64_BIG:
2891       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2892                                           dynsym_xindex, of);
2893       break;
2894 #endif
2895     default:
2896       gold_unreachable();
2897     }
2898 }
2899
2900 // Write out the global symbols.
2901
2902 template<int size, bool big_endian>
2903 void
2904 Symbol_table::sized_write_globals(const Stringpool* sympool,
2905                                   const Stringpool* dynpool,
2906                                   Output_symtab_xindex* symtab_xindex,
2907                                   Output_symtab_xindex* dynsym_xindex,
2908                                   Output_file* of) const
2909 {
2910   const Target& target = parameters->target();
2911
2912   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2913
2914   const unsigned int output_count = this->output_count_;
2915   const section_size_type oview_size = output_count * sym_size;
2916   const unsigned int first_global_index = this->first_global_index_;
2917   unsigned char* psyms;
2918   if (this->offset_ == 0 || output_count == 0)
2919     psyms = NULL;
2920   else
2921     psyms = of->get_output_view(this->offset_, oview_size);
2922
2923   const unsigned int dynamic_count = this->dynamic_count_;
2924   const section_size_type dynamic_size = dynamic_count * sym_size;
2925   const unsigned int first_dynamic_global_index =
2926     this->first_dynamic_global_index_;
2927   unsigned char* dynamic_view;
2928   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2929     dynamic_view = NULL;
2930   else
2931     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2932
2933   for (Symbol_table_type::const_iterator p = this->table_.begin();
2934        p != this->table_.end();
2935        ++p)
2936     {
2937       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2938
2939       // Possibly warn about unresolved symbols in shared libraries.
2940       this->warn_about_undefined_dynobj_symbol(sym);
2941
2942       unsigned int sym_index = sym->symtab_index();
2943       unsigned int dynsym_index;
2944       if (dynamic_view == NULL)
2945         dynsym_index = -1U;
2946       else
2947         dynsym_index = sym->dynsym_index();
2948
2949       if (sym_index == -1U && dynsym_index == -1U)
2950         {
2951           // This symbol is not included in the output file.
2952           continue;
2953         }
2954
2955       unsigned int shndx;
2956       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2957       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2958       elfcpp::STB binding = sym->binding();
2959
2960       // If --weak-unresolved-symbols is set, change binding of unresolved
2961       // global symbols to STB_WEAK.
2962       if (parameters->options().weak_unresolved_symbols()
2963           && binding == elfcpp::STB_GLOBAL
2964           && sym->is_undefined())
2965         binding = elfcpp::STB_WEAK;
2966
2967       // If --no-gnu-unique is set, change STB_GNU_UNIQUE to STB_GLOBAL.
2968       if (binding == elfcpp::STB_GNU_UNIQUE
2969           && !parameters->options().gnu_unique())
2970         binding = elfcpp::STB_GLOBAL;
2971
2972       switch (sym->source())
2973         {
2974         case Symbol::FROM_OBJECT:
2975           {
2976             bool is_ordinary;
2977             unsigned int in_shndx = sym->shndx(&is_ordinary);
2978
2979             if (!is_ordinary
2980                 && in_shndx != elfcpp::SHN_ABS
2981                 && !Symbol::is_common_shndx(in_shndx))
2982               {
2983                 gold_error(_("%s: unsupported symbol section 0x%x"),
2984                            sym->demangled_name().c_str(), in_shndx);
2985                 shndx = in_shndx;
2986               }
2987             else
2988               {
2989                 Object* symobj = sym->object();
2990                 if (symobj->is_dynamic())
2991                   {
2992                     if (sym->needs_dynsym_value())
2993                       dynsym_value = target.dynsym_value(sym);
2994                     shndx = elfcpp::SHN_UNDEF;
2995                     if (sym->is_undef_binding_weak())
2996                       binding = elfcpp::STB_WEAK;
2997                     else
2998                       binding = elfcpp::STB_GLOBAL;
2999                   }
3000                 else if (symobj->pluginobj() != NULL)
3001                   shndx = elfcpp::SHN_UNDEF;
3002                 else if (in_shndx == elfcpp::SHN_UNDEF
3003                          || (!is_ordinary
3004                              && (in_shndx == elfcpp::SHN_ABS
3005                                  || Symbol::is_common_shndx(in_shndx))))
3006                   shndx = in_shndx;
3007                 else
3008                   {
3009                     Relobj* relobj = static_cast<Relobj*>(symobj);
3010                     Output_section* os = relobj->output_section(in_shndx);
3011                     if (this->is_section_folded(relobj, in_shndx))
3012                       {
3013                         // This global symbol must be written out even though
3014                         // it is folded.
3015                         // Get the os of the section it is folded onto.
3016                         Section_id folded =
3017                              this->icf_->get_folded_section(relobj, in_shndx);
3018                         gold_assert(folded.first !=NULL);
3019                         Relobj* folded_obj =
3020                           reinterpret_cast<Relobj*>(folded.first);
3021                         os = folded_obj->output_section(folded.second);
3022                         gold_assert(os != NULL);
3023                       }
3024                     gold_assert(os != NULL);
3025                     shndx = os->out_shndx();
3026
3027                     if (shndx >= elfcpp::SHN_LORESERVE)
3028                       {
3029                         if (sym_index != -1U)
3030                           symtab_xindex->add(sym_index, shndx);
3031                         if (dynsym_index != -1U)
3032                           dynsym_xindex->add(dynsym_index, shndx);
3033                         shndx = elfcpp::SHN_XINDEX;
3034                       }
3035
3036                     // In object files symbol values are section
3037                     // relative.
3038                     if (parameters->options().relocatable())
3039                       sym_value -= os->address();
3040                   }
3041               }
3042           }
3043           break;
3044
3045         case Symbol::IN_OUTPUT_DATA:
3046           {
3047             Output_data* od = sym->output_data();
3048
3049             shndx = od->out_shndx();
3050             if (shndx >= elfcpp::SHN_LORESERVE)
3051               {
3052                 if (sym_index != -1U)
3053                   symtab_xindex->add(sym_index, shndx);
3054                 if (dynsym_index != -1U)
3055                   dynsym_xindex->add(dynsym_index, shndx);
3056                 shndx = elfcpp::SHN_XINDEX;
3057               }
3058
3059             // In object files symbol values are section
3060             // relative.
3061             if (parameters->options().relocatable())
3062               sym_value -= od->address();
3063           }
3064           break;
3065
3066         case Symbol::IN_OUTPUT_SEGMENT:
3067           shndx = elfcpp::SHN_ABS;
3068           break;
3069
3070         case Symbol::IS_CONSTANT:
3071           shndx = elfcpp::SHN_ABS;
3072           break;
3073
3074         case Symbol::IS_UNDEFINED:
3075           shndx = elfcpp::SHN_UNDEF;
3076           break;
3077
3078         default:
3079           gold_unreachable();
3080         }
3081
3082       if (sym_index != -1U)
3083         {
3084           sym_index -= first_global_index;
3085           gold_assert(sym_index < output_count);
3086           unsigned char* ps = psyms + (sym_index * sym_size);
3087           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
3088                                                      binding, sympool, ps);
3089         }
3090
3091       if (dynsym_index != -1U)
3092         {
3093           dynsym_index -= first_dynamic_global_index;
3094           gold_assert(dynsym_index < dynamic_count);
3095           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
3096           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
3097                                                      binding, dynpool, pd);
3098           // Allow a target to adjust dynamic symbol value.
3099           parameters->target().adjust_dyn_symbol(sym, pd);
3100         }
3101     }
3102
3103   of->write_output_view(this->offset_, oview_size, psyms);
3104   if (dynamic_view != NULL)
3105     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
3106 }
3107
3108 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
3109 // strtab holding the name.
3110
3111 template<int size, bool big_endian>
3112 void
3113 Symbol_table::sized_write_symbol(
3114     Sized_symbol<size>* sym,
3115     typename elfcpp::Elf_types<size>::Elf_Addr value,
3116     unsigned int shndx,
3117     elfcpp::STB binding,
3118     const Stringpool* pool,
3119     unsigned char* p) const
3120 {
3121   elfcpp::Sym_write<size, big_endian> osym(p);
3122   if (sym->version() == NULL || !parameters->options().relocatable())
3123     osym.put_st_name(pool->get_offset(sym->name()));
3124   else
3125     osym.put_st_name(pool->get_offset(sym->versioned_name()));
3126   osym.put_st_value(value);
3127   // Use a symbol size of zero for undefined symbols from shared libraries.
3128   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
3129     osym.put_st_size(0);
3130   else
3131     osym.put_st_size(sym->symsize());
3132   elfcpp::STT type = sym->type();
3133   gold_assert(type != elfcpp::STT_GNU_IFUNC || !sym->is_from_dynobj());
3134   // A version script may have overridden the default binding.
3135   if (sym->is_forced_local())
3136     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
3137   else
3138     osym.put_st_info(elfcpp::elf_st_info(binding, type));
3139   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
3140   osym.put_st_shndx(shndx);
3141 }
3142
3143 // Check for unresolved symbols in shared libraries.  This is
3144 // controlled by the --allow-shlib-undefined option.
3145
3146 // We only warn about libraries for which we have seen all the
3147 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
3148 // which were not seen in this link.  If we didn't see a DT_NEEDED
3149 // entry, we aren't going to be able to reliably report whether the
3150 // symbol is undefined.
3151
3152 // We also don't warn about libraries found in a system library
3153 // directory (e.g., /lib or /usr/lib); we assume that those libraries
3154 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
3155 // can have undefined references satisfied by ld-linux.so.
3156
3157 inline void
3158 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
3159 {
3160   bool dummy;
3161   if (sym->source() == Symbol::FROM_OBJECT
3162       && sym->object()->is_dynamic()
3163       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
3164       && sym->binding() != elfcpp::STB_WEAK
3165       && !parameters->options().allow_shlib_undefined()
3166       && !parameters->target().is_defined_by_abi(sym)
3167       && !sym->object()->is_in_system_directory())
3168     {
3169       // A very ugly cast.
3170       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
3171       if (!dynobj->has_unknown_needed_entries())
3172         gold_undefined_symbol(sym);
3173     }
3174 }
3175
3176 // Write out a section symbol.  Return the update offset.
3177
3178 void
3179 Symbol_table::write_section_symbol(const Output_section* os,
3180                                    Output_symtab_xindex* symtab_xindex,
3181                                    Output_file* of,
3182                                    off_t offset) const
3183 {
3184   switch (parameters->size_and_endianness())
3185     {
3186 #ifdef HAVE_TARGET_32_LITTLE
3187     case Parameters::TARGET_32_LITTLE:
3188       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
3189                                                   offset);
3190       break;
3191 #endif
3192 #ifdef HAVE_TARGET_32_BIG
3193     case Parameters::TARGET_32_BIG:
3194       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
3195                                                  offset);
3196       break;
3197 #endif
3198 #ifdef HAVE_TARGET_64_LITTLE
3199     case Parameters::TARGET_64_LITTLE:
3200       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
3201                                                   offset);
3202       break;
3203 #endif
3204 #ifdef HAVE_TARGET_64_BIG
3205     case Parameters::TARGET_64_BIG:
3206       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
3207                                                  offset);
3208       break;
3209 #endif
3210     default:
3211       gold_unreachable();
3212     }
3213 }
3214
3215 // Write out a section symbol, specialized for size and endianness.
3216
3217 template<int size, bool big_endian>
3218 void
3219 Symbol_table::sized_write_section_symbol(const Output_section* os,
3220                                          Output_symtab_xindex* symtab_xindex,
3221                                          Output_file* of,
3222                                          off_t offset) const
3223 {
3224   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
3225
3226   unsigned char* pov = of->get_output_view(offset, sym_size);
3227
3228   elfcpp::Sym_write<size, big_endian> osym(pov);
3229   osym.put_st_name(0);
3230   if (parameters->options().relocatable())
3231     osym.put_st_value(0);
3232   else
3233     osym.put_st_value(os->address());
3234   osym.put_st_size(0);
3235   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
3236                                        elfcpp::STT_SECTION));
3237   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
3238
3239   unsigned int shndx = os->out_shndx();
3240   if (shndx >= elfcpp::SHN_LORESERVE)
3241     {
3242       symtab_xindex->add(os->symtab_index(), shndx);
3243       shndx = elfcpp::SHN_XINDEX;
3244     }
3245   osym.put_st_shndx(shndx);
3246
3247   of->write_output_view(offset, sym_size, pov);
3248 }
3249
3250 // Print statistical information to stderr.  This is used for --stats.
3251
3252 void
3253 Symbol_table::print_stats() const
3254 {
3255 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
3256   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
3257           program_name, this->table_.size(), this->table_.bucket_count());
3258 #else
3259   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
3260           program_name, this->table_.size());
3261 #endif
3262   this->namepool_.print_stats("symbol table stringpool");
3263 }
3264
3265 // We check for ODR violations by looking for symbols with the same
3266 // name for which the debugging information reports that they were
3267 // defined in disjoint source locations.  When comparing the source
3268 // location, we consider instances with the same base filename to be
3269 // the same.  This is because different object files/shared libraries
3270 // can include the same header file using different paths, and
3271 // different optimization settings can make the line number appear to
3272 // be a couple lines off, and we don't want to report an ODR violation
3273 // in those cases.
3274
3275 // This struct is used to compare line information, as returned by
3276 // Dwarf_line_info::one_addr2line.  It implements a < comparison
3277 // operator used with std::sort.
3278
3279 struct Odr_violation_compare
3280 {
3281   bool
3282   operator()(const std::string& s1, const std::string& s2) const
3283   {
3284     // Inputs should be of the form "dirname/filename:linenum" where
3285     // "dirname/" is optional.  We want to compare just the filename:linenum.
3286
3287     // Find the last '/' in each string.
3288     std::string::size_type s1begin = s1.rfind('/');
3289     std::string::size_type s2begin = s2.rfind('/');
3290     // If there was no '/' in a string, start at the beginning.
3291     if (s1begin == std::string::npos)
3292       s1begin = 0;
3293     if (s2begin == std::string::npos)
3294       s2begin = 0;
3295     return s1.compare(s1begin, std::string::npos,
3296                       s2, s2begin, std::string::npos) < 0;
3297   }
3298 };
3299
3300 // Returns all of the lines attached to LOC, not just the one the
3301 // instruction actually came from.
3302 std::vector<std::string>
3303 Symbol_table::linenos_from_loc(const Task* task,
3304                                const Symbol_location& loc)
3305 {
3306   // We need to lock the object in order to read it.  This
3307   // means that we have to run in a singleton Task.  If we
3308   // want to run this in a general Task for better
3309   // performance, we will need one Task for object, plus
3310   // appropriate locking to ensure that we don't conflict with
3311   // other uses of the object.  Also note, one_addr2line is not
3312   // currently thread-safe.
3313   Task_lock_obj<Object> tl(task, loc.object);
3314
3315   std::vector<std::string> result;
3316   Symbol_location code_loc = loc;
3317   parameters->target().function_location(&code_loc);
3318   // 16 is the size of the object-cache that one_addr2line should use.
3319   std::string canonical_result = Dwarf_line_info::one_addr2line(
3320       code_loc.object, code_loc.shndx, code_loc.offset, 16, &result);
3321   if (!canonical_result.empty())
3322     result.push_back(canonical_result);
3323   return result;
3324 }
3325
3326 // OutputIterator that records if it was ever assigned to.  This
3327 // allows it to be used with std::set_intersection() to check for
3328 // intersection rather than computing the intersection.
3329 struct Check_intersection
3330 {
3331   Check_intersection()
3332     : value_(false)
3333   {}
3334
3335   bool had_intersection() const
3336   { return this->value_; }
3337
3338   Check_intersection& operator++()
3339   { return *this; }
3340
3341   Check_intersection& operator*()
3342   { return *this; }
3343
3344   template<typename T>
3345   Check_intersection& operator=(const T&)
3346   {
3347     this->value_ = true;
3348     return *this;
3349   }
3350
3351  private:
3352   bool value_;
3353 };
3354
3355 // Check candidate_odr_violations_ to find symbols with the same name
3356 // but apparently different definitions (different source-file/line-no
3357 // for each line assigned to the first instruction).
3358
3359 void
3360 Symbol_table::detect_odr_violations(const Task* task,
3361                                     const char* output_file_name) const
3362 {
3363   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3364        it != candidate_odr_violations_.end();
3365        ++it)
3366     {
3367       const char* const symbol_name = it->first;
3368
3369       std::string first_object_name;
3370       std::vector<std::string> first_object_linenos;
3371
3372       Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3373           locs = it->second.begin();
3374       const Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3375           locs_end = it->second.end();
3376       for (; locs != locs_end && first_object_linenos.empty(); ++locs)
3377         {
3378           // Save the line numbers from the first definition to
3379           // compare to the other definitions.  Ideally, we'd compare
3380           // every definition to every other, but we don't want to
3381           // take O(N^2) time to do this.  This shortcut may cause
3382           // false negatives that appear or disappear depending on the
3383           // link order, but it won't cause false positives.
3384           first_object_name = locs->object->name();
3385           first_object_linenos = this->linenos_from_loc(task, *locs);
3386         }
3387       if (first_object_linenos.empty())
3388         continue;
3389
3390       // Sort by Odr_violation_compare to make std::set_intersection work.
3391       std::string first_object_canonical_result = first_object_linenos.back();
3392       std::sort(first_object_linenos.begin(), first_object_linenos.end(),
3393                 Odr_violation_compare());
3394
3395       for (; locs != locs_end; ++locs)
3396         {
3397           std::vector<std::string> linenos =
3398               this->linenos_from_loc(task, *locs);
3399           // linenos will be empty if we couldn't parse the debug info.
3400           if (linenos.empty())
3401             continue;
3402           // Sort by Odr_violation_compare to make std::set_intersection work.
3403           gold_assert(!linenos.empty());
3404           std::string second_object_canonical_result = linenos.back();
3405           std::sort(linenos.begin(), linenos.end(), Odr_violation_compare());
3406
3407           Check_intersection intersection_result =
3408               std::set_intersection(first_object_linenos.begin(),
3409                                     first_object_linenos.end(),
3410                                     linenos.begin(),
3411                                     linenos.end(),
3412                                     Check_intersection(),
3413                                     Odr_violation_compare());
3414           if (!intersection_result.had_intersection())
3415             {
3416               gold_warning(_("while linking %s: symbol '%s' defined in "
3417                              "multiple places (possible ODR violation):"),
3418                            output_file_name, demangle(symbol_name).c_str());
3419               // This only prints one location from each definition,
3420               // which may not be the location we expect to intersect
3421               // with another definition.  We could print the whole
3422               // set of locations, but that seems too verbose.
3423               fprintf(stderr, _("  %s from %s\n"),
3424                       first_object_canonical_result.c_str(),
3425                       first_object_name.c_str());
3426               fprintf(stderr, _("  %s from %s\n"),
3427                       second_object_canonical_result.c_str(),
3428                       locs->object->name().c_str());
3429               // Only print one broken pair, to avoid needing to
3430               // compare against a list of the disjoint definition
3431               // locations we've found so far.  (If we kept comparing
3432               // against just the first one, we'd get a lot of
3433               // redundant complaints about the second definition
3434               // location.)
3435               break;
3436             }
3437         }
3438     }
3439   // We only call one_addr2line() in this function, so we can clear its cache.
3440   Dwarf_line_info::clear_addr2line_cache();
3441 }
3442
3443 // Warnings functions.
3444
3445 // Add a new warning.
3446
3447 void
3448 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3449                       const std::string& warning)
3450 {
3451   name = symtab->canonicalize_name(name);
3452   this->warnings_[name].set(obj, warning);
3453 }
3454
3455 // Look through the warnings and mark the symbols for which we should
3456 // warn.  This is called during Layout::finalize when we know the
3457 // sources for all the symbols.
3458
3459 void
3460 Warnings::note_warnings(Symbol_table* symtab)
3461 {
3462   for (Warning_table::iterator p = this->warnings_.begin();
3463        p != this->warnings_.end();
3464        ++p)
3465     {
3466       Symbol* sym = symtab->lookup(p->first, NULL);
3467       if (sym != NULL
3468           && sym->source() == Symbol::FROM_OBJECT
3469           && sym->object() == p->second.object)
3470         sym->set_has_warning();
3471     }
3472 }
3473
3474 // Issue a warning.  This is called when we see a relocation against a
3475 // symbol for which has a warning.
3476
3477 template<int size, bool big_endian>
3478 void
3479 Warnings::issue_warning(const Symbol* sym,
3480                         const Relocate_info<size, big_endian>* relinfo,
3481                         size_t relnum, off_t reloffset) const
3482 {
3483   gold_assert(sym->has_warning());
3484
3485   // We don't want to issue a warning for a relocation against the
3486   // symbol in the same object file in which the symbol is defined.
3487   if (sym->object() == relinfo->object)
3488     return;
3489
3490   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3491   gold_assert(p != this->warnings_.end());
3492   gold_warning_at_location(relinfo, relnum, reloffset,
3493                            "%s", p->second.text.c_str());
3494 }
3495
3496 // Instantiate the templates we need.  We could use the configure
3497 // script to restrict this to only the ones needed for implemented
3498 // targets.
3499
3500 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3501 template
3502 void
3503 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3504 #endif
3505
3506 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3507 template
3508 void
3509 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3510 #endif
3511
3512 #ifdef HAVE_TARGET_32_LITTLE
3513 template
3514 void
3515 Symbol_table::add_from_relobj<32, false>(
3516     Sized_relobj_file<32, false>* relobj,
3517     const unsigned char* syms,
3518     size_t count,
3519     size_t symndx_offset,
3520     const char* sym_names,
3521     size_t sym_name_size,
3522     Sized_relobj_file<32, false>::Symbols* sympointers,
3523     size_t* defined);
3524 #endif
3525
3526 #ifdef HAVE_TARGET_32_BIG
3527 template
3528 void
3529 Symbol_table::add_from_relobj<32, true>(
3530     Sized_relobj_file<32, true>* relobj,
3531     const unsigned char* syms,
3532     size_t count,
3533     size_t symndx_offset,
3534     const char* sym_names,
3535     size_t sym_name_size,
3536     Sized_relobj_file<32, true>::Symbols* sympointers,
3537     size_t* defined);
3538 #endif
3539
3540 #ifdef HAVE_TARGET_64_LITTLE
3541 template
3542 void
3543 Symbol_table::add_from_relobj<64, false>(
3544     Sized_relobj_file<64, false>* relobj,
3545     const unsigned char* syms,
3546     size_t count,
3547     size_t symndx_offset,
3548     const char* sym_names,
3549     size_t sym_name_size,
3550     Sized_relobj_file<64, false>::Symbols* sympointers,
3551     size_t* defined);
3552 #endif
3553
3554 #ifdef HAVE_TARGET_64_BIG
3555 template
3556 void
3557 Symbol_table::add_from_relobj<64, true>(
3558     Sized_relobj_file<64, true>* relobj,
3559     const unsigned char* syms,
3560     size_t count,
3561     size_t symndx_offset,
3562     const char* sym_names,
3563     size_t sym_name_size,
3564     Sized_relobj_file<64, true>::Symbols* sympointers,
3565     size_t* defined);
3566 #endif
3567
3568 #ifdef HAVE_TARGET_32_LITTLE
3569 template
3570 Symbol*
3571 Symbol_table::add_from_pluginobj<32, false>(
3572     Sized_pluginobj<32, false>* obj,
3573     const char* name,
3574     const char* ver,
3575     elfcpp::Sym<32, false>* sym);
3576 #endif
3577
3578 #ifdef HAVE_TARGET_32_BIG
3579 template
3580 Symbol*
3581 Symbol_table::add_from_pluginobj<32, true>(
3582     Sized_pluginobj<32, true>* obj,
3583     const char* name,
3584     const char* ver,
3585     elfcpp::Sym<32, true>* sym);
3586 #endif
3587
3588 #ifdef HAVE_TARGET_64_LITTLE
3589 template
3590 Symbol*
3591 Symbol_table::add_from_pluginobj<64, false>(
3592     Sized_pluginobj<64, false>* obj,
3593     const char* name,
3594     const char* ver,
3595     elfcpp::Sym<64, false>* sym);
3596 #endif
3597
3598 #ifdef HAVE_TARGET_64_BIG
3599 template
3600 Symbol*
3601 Symbol_table::add_from_pluginobj<64, true>(
3602     Sized_pluginobj<64, true>* obj,
3603     const char* name,
3604     const char* ver,
3605     elfcpp::Sym<64, true>* sym);
3606 #endif
3607
3608 #ifdef HAVE_TARGET_32_LITTLE
3609 template
3610 void
3611 Symbol_table::add_from_dynobj<32, false>(
3612     Sized_dynobj<32, false>* dynobj,
3613     const unsigned char* syms,
3614     size_t count,
3615     const char* sym_names,
3616     size_t sym_name_size,
3617     const unsigned char* versym,
3618     size_t versym_size,
3619     const std::vector<const char*>* version_map,
3620     Sized_relobj_file<32, false>::Symbols* sympointers,
3621     size_t* defined);
3622 #endif
3623
3624 #ifdef HAVE_TARGET_32_BIG
3625 template
3626 void
3627 Symbol_table::add_from_dynobj<32, true>(
3628     Sized_dynobj<32, true>* dynobj,
3629     const unsigned char* syms,
3630     size_t count,
3631     const char* sym_names,
3632     size_t sym_name_size,
3633     const unsigned char* versym,
3634     size_t versym_size,
3635     const std::vector<const char*>* version_map,
3636     Sized_relobj_file<32, true>::Symbols* sympointers,
3637     size_t* defined);
3638 #endif
3639
3640 #ifdef HAVE_TARGET_64_LITTLE
3641 template
3642 void
3643 Symbol_table::add_from_dynobj<64, false>(
3644     Sized_dynobj<64, false>* dynobj,
3645     const unsigned char* syms,
3646     size_t count,
3647     const char* sym_names,
3648     size_t sym_name_size,
3649     const unsigned char* versym,
3650     size_t versym_size,
3651     const std::vector<const char*>* version_map,
3652     Sized_relobj_file<64, false>::Symbols* sympointers,
3653     size_t* defined);
3654 #endif
3655
3656 #ifdef HAVE_TARGET_64_BIG
3657 template
3658 void
3659 Symbol_table::add_from_dynobj<64, true>(
3660     Sized_dynobj<64, true>* dynobj,
3661     const unsigned char* syms,
3662     size_t count,
3663     const char* sym_names,
3664     size_t sym_name_size,
3665     const unsigned char* versym,
3666     size_t versym_size,
3667     const std::vector<const char*>* version_map,
3668     Sized_relobj_file<64, true>::Symbols* sympointers,
3669     size_t* defined);
3670 #endif
3671
3672 #ifdef HAVE_TARGET_32_LITTLE
3673 template
3674 Sized_symbol<32>*
3675 Symbol_table::add_from_incrobj(
3676     Object* obj,
3677     const char* name,
3678     const char* ver,
3679     elfcpp::Sym<32, false>* sym);
3680 #endif
3681
3682 #ifdef HAVE_TARGET_32_BIG
3683 template
3684 Sized_symbol<32>*
3685 Symbol_table::add_from_incrobj(
3686     Object* obj,
3687     const char* name,
3688     const char* ver,
3689     elfcpp::Sym<32, true>* sym);
3690 #endif
3691
3692 #ifdef HAVE_TARGET_64_LITTLE
3693 template
3694 Sized_symbol<64>*
3695 Symbol_table::add_from_incrobj(
3696     Object* obj,
3697     const char* name,
3698     const char* ver,
3699     elfcpp::Sym<64, false>* sym);
3700 #endif
3701
3702 #ifdef HAVE_TARGET_64_BIG
3703 template
3704 Sized_symbol<64>*
3705 Symbol_table::add_from_incrobj(
3706     Object* obj,
3707     const char* name,
3708     const char* ver,
3709     elfcpp::Sym<64, true>* sym);
3710 #endif
3711
3712 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3713 template
3714 void
3715 Symbol_table::define_with_copy_reloc<32>(
3716     Sized_symbol<32>* sym,
3717     Output_data* posd,
3718     elfcpp::Elf_types<32>::Elf_Addr value);
3719 #endif
3720
3721 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3722 template
3723 void
3724 Symbol_table::define_with_copy_reloc<64>(
3725     Sized_symbol<64>* sym,
3726     Output_data* posd,
3727     elfcpp::Elf_types<64>::Elf_Addr value);
3728 #endif
3729
3730 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3731 template
3732 void
3733 Sized_symbol<32>::init_output_data(const char* name, const char* version,
3734                                    Output_data* od, Value_type value,
3735                                    Size_type symsize, elfcpp::STT type,
3736                                    elfcpp::STB binding,
3737                                    elfcpp::STV visibility,
3738                                    unsigned char nonvis,
3739                                    bool offset_is_from_end,
3740                                    bool is_predefined);
3741 #endif
3742
3743 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3744 template
3745 void
3746 Sized_symbol<64>::init_output_data(const char* name, const char* version,
3747                                    Output_data* od, Value_type value,
3748                                    Size_type symsize, elfcpp::STT type,
3749                                    elfcpp::STB binding,
3750                                    elfcpp::STV visibility,
3751                                    unsigned char nonvis,
3752                                    bool offset_is_from_end,
3753                                    bool is_predefined);
3754 #endif
3755
3756 #ifdef HAVE_TARGET_32_LITTLE
3757 template
3758 void
3759 Warnings::issue_warning<32, false>(const Symbol* sym,
3760                                    const Relocate_info<32, false>* relinfo,
3761                                    size_t relnum, off_t reloffset) const;
3762 #endif
3763
3764 #ifdef HAVE_TARGET_32_BIG
3765 template
3766 void
3767 Warnings::issue_warning<32, true>(const Symbol* sym,
3768                                   const Relocate_info<32, true>* relinfo,
3769                                   size_t relnum, off_t reloffset) const;
3770 #endif
3771
3772 #ifdef HAVE_TARGET_64_LITTLE
3773 template
3774 void
3775 Warnings::issue_warning<64, false>(const Symbol* sym,
3776                                    const Relocate_info<64, false>* relinfo,
3777                                    size_t relnum, off_t reloffset) const;
3778 #endif
3779
3780 #ifdef HAVE_TARGET_64_BIG
3781 template
3782 void
3783 Warnings::issue_warning<64, true>(const Symbol* sym,
3784                                   const Relocate_info<64, true>* relinfo,
3785                                   size_t relnum, off_t reloffset) const;
3786 #endif
3787
3788 } // End namespace gold.