contrib/binutils-2.21/gold/symtab.cc

   1 // symtab.cc -- the gold symbol table
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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
  44 namespace gold
  45 {
  46
  47 // Class Symbol.
  48
  49 // Initialize fields in Symbol.  This initializes everything except u_
  50 // and source_.
  51
  52 void
  53 Symbol::init_fields(const char* name, const char* version,
  54                     elfcpp::STT type, elfcpp::STB binding,
  55                     elfcpp::STV visibility, unsigned char nonvis)
  56 {
  57   this->name_ = name;
  58   this->version_ = version;
  59   this->symtab_index_ = 0;
  60   this->dynsym_index_ = 0;
  61   this->got_offsets_.init();
  62   this->plt_offset_ = -1U;
  63   this->type_ = type;
  64   this->binding_ = binding;
  65   this->visibility_ = visibility;
  66   this->nonvis_ = nonvis;
  67   this->is_def_ = false;
  68   this->is_forwarder_ = false;
  69   this->has_alias_ = false;
  70   this->needs_dynsym_entry_ = false;
  71   this->in_reg_ = false;
  72   this->in_dyn_ = false;
  73   this->has_warning_ = false;
  74   this->is_copied_from_dynobj_ = false;
  75   this->is_forced_local_ = false;
  76   this->is_ordinary_shndx_ = false;
  77   this->in_real_elf_ = false;
  78   this->is_defined_in_discarded_section_ = false;
  79   this->undef_binding_set_ = false;
  80   this->undef_binding_weak_ = false;
  81 }
  82
  83 // Return the demangled version of the symbol's name, but only
  84 // if the --demangle flag was set.
  85
  86 static std::string
  87 demangle(const char* name)
  88 {
  89   if (!parameters->options().do_demangle())
  90     return name;
  91
  92   // cplus_demangle allocates memory for the result it returns,
  93   // and returns NULL if the name is already demangled.
  94   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
  95   if (demangled_name == NULL)
  96     return name;
  97
  98   std::string retval(demangled_name);
  99   free(demangled_name);
 100   return retval;
 101 }
 102
 103 std::string
 104 Symbol::demangled_name() const
 105 {
 106   return demangle(this->name());
 107 }
 108
 109 // Initialize the fields in the base class Symbol for SYM in OBJECT.
 110
 111 template<int size, bool big_endian>
 112 void
 113 Symbol::init_base_object(const char* name, const char* version, Object* object,
 114                          const elfcpp::Sym<size, big_endian>& sym,
 115                          unsigned int st_shndx, bool is_ordinary)
 116 {
 117   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
 118                     sym.get_st_visibility(), sym.get_st_nonvis());
 119   this->u_.from_object.object = object;
 120   this->u_.from_object.shndx = st_shndx;
 121   this->is_ordinary_shndx_ = is_ordinary;
 122   this->source_ = FROM_OBJECT;
 123   this->in_reg_ = !object->is_dynamic();
 124   this->in_dyn_ = object->is_dynamic();
 125   this->in_real_elf_ = object->pluginobj() == NULL;
 126 }
 127
 128 // Initialize the fields in the base class Symbol for a symbol defined
 129 // in an Output_data.
 130
 131 void
 132 Symbol::init_base_output_data(const char* name, const char* version,
 133                               Output_data* od, elfcpp::STT type,
 134                               elfcpp::STB binding, elfcpp::STV visibility,
 135                               unsigned char nonvis, bool offset_is_from_end)
 136 {
 137   this->init_fields(name, version, type, binding, visibility, nonvis);
 138   this->u_.in_output_data.output_data = od;
 139   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
 140   this->source_ = IN_OUTPUT_DATA;
 141   this->in_reg_ = true;
 142   this->in_real_elf_ = true;
 143 }
 144
 145 // Initialize the fields in the base class Symbol for a symbol defined
 146 // in an Output_segment.
 147
 148 void
 149 Symbol::init_base_output_segment(const char* name, const char* version,
 150                                  Output_segment* os, elfcpp::STT type,
 151                                  elfcpp::STB binding, elfcpp::STV visibility,
 152                                  unsigned char nonvis,
 153                                  Segment_offset_base offset_base)
 154 {
 155   this->init_fields(name, version, type, binding, visibility, nonvis);
 156   this->u_.in_output_segment.output_segment = os;
 157   this->u_.in_output_segment.offset_base = offset_base;
 158   this->source_ = IN_OUTPUT_SEGMENT;
 159   this->in_reg_ = true;
 160   this->in_real_elf_ = true;
 161 }
 162
 163 // Initialize the fields in the base class Symbol for a symbol defined
 164 // as a constant.
 165
 166 void
 167 Symbol::init_base_constant(const char* name, const char* version,
 168                            elfcpp::STT type, elfcpp::STB binding,
 169                            elfcpp::STV visibility, unsigned char nonvis)
 170 {
 171   this->init_fields(name, version, type, binding, visibility, nonvis);
 172   this->source_ = IS_CONSTANT;
 173   this->in_reg_ = true;
 174   this->in_real_elf_ = true;
 175 }
 176
 177 // Initialize the fields in the base class Symbol for an undefined
 178 // symbol.
 179
 180 void
 181 Symbol::init_base_undefined(const char* name, const char* version,
 182                             elfcpp::STT type, elfcpp::STB binding,
 183                             elfcpp::STV visibility, unsigned char nonvis)
 184 {
 185   this->init_fields(name, version, type, binding, visibility, nonvis);
 186   this->dynsym_index_ = -1U;
 187   this->source_ = IS_UNDEFINED;
 188   this->in_reg_ = true;
 189   this->in_real_elf_ = true;
 190 }
 191
 192 // Allocate a common symbol in the base.
 193
 194 void
 195 Symbol::allocate_base_common(Output_data* od)
 196 {
 197   gold_assert(this->is_common());
 198   this->source_ = IN_OUTPUT_DATA;
 199   this->u_.in_output_data.output_data = od;
 200   this->u_.in_output_data.offset_is_from_end = false;
 201 }
 202
 203 // Initialize the fields in Sized_symbol for SYM in OBJECT.
 204
 205 template<int size>
 206 template<bool big_endian>
 207 void
 208 Sized_symbol<size>::init_object(const char* name, const char* version,
 209                                 Object* object,
 210                                 const elfcpp::Sym<size, big_endian>& sym,
 211                                 unsigned int st_shndx, bool is_ordinary)
 212 {
 213   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
 214   this->value_ = sym.get_st_value();
 215   this->symsize_ = sym.get_st_size();
 216 }
 217
 218 // Initialize the fields in Sized_symbol for a symbol defined in an
 219 // Output_data.
 220
 221 template<int size>
 222 void
 223 Sized_symbol<size>::init_output_data(const char* name, const char* version,
 224                                      Output_data* od, Value_type value,
 225                                      Size_type symsize, elfcpp::STT type,
 226                                      elfcpp::STB binding,
 227                                      elfcpp::STV visibility,
 228                                      unsigned char nonvis,
 229                                      bool offset_is_from_end)
 230 {
 231   this->init_base_output_data(name, version, od, type, binding, visibility,
 232                               nonvis, offset_is_from_end);
 233   this->value_ = value;
 234   this->symsize_ = symsize;
 235 }
 236
 237 // Initialize the fields in Sized_symbol for a symbol defined in an
 238 // Output_segment.
 239
 240 template<int size>
 241 void
 242 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
 243                                         Output_segment* os, Value_type value,
 244                                         Size_type symsize, elfcpp::STT type,
 245                                         elfcpp::STB binding,
 246                                         elfcpp::STV visibility,
 247                                         unsigned char nonvis,
 248                                         Segment_offset_base offset_base)
 249 {
 250   this->init_base_output_segment(name, version, os, type, binding, visibility,
 251                                  nonvis, offset_base);
 252   this->value_ = value;
 253   this->symsize_ = symsize;
 254 }
 255
 256 // Initialize the fields in Sized_symbol for a symbol defined as a
 257 // constant.
 258
 259 template<int size>
 260 void
 261 Sized_symbol<size>::init_constant(const char* name, const char* version,
 262                                   Value_type value, Size_type symsize,
 263                                   elfcpp::STT type, elfcpp::STB binding,
 264                                   elfcpp::STV visibility, unsigned char nonvis)
 265 {
 266   this->init_base_constant(name, version, type, binding, visibility, nonvis);
 267   this->value_ = value;
 268   this->symsize_ = symsize;
 269 }
 270
 271 // Initialize the fields in Sized_symbol for an undefined symbol.
 272
 273 template<int size>
 274 void
 275 Sized_symbol<size>::init_undefined(const char* name, const char* version,
 276                                    elfcpp::STT type, elfcpp::STB binding,
 277                                    elfcpp::STV visibility, unsigned char nonvis)
 278 {
 279   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
 280   this->value_ = 0;
 281   this->symsize_ = 0;
 282 }
 283
 284 // Return true if SHNDX represents a common symbol.
 285
 286 bool
 287 Symbol::is_common_shndx(unsigned int shndx)
 288 {
 289   return (shndx == elfcpp::SHN_COMMON
 290           || shndx == parameters->target().small_common_shndx()
 291           || shndx == parameters->target().large_common_shndx());
 292 }
 293
 294 // Allocate a common symbol.
 295
 296 template<int size>
 297 void
 298 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
 299 {
 300   this->allocate_base_common(od);
 301   this->value_ = value;
 302 }
 303
 304 // The ""'s around str ensure str is a string literal, so sizeof works.
 305 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
 306
 307 // Return true if this symbol should be added to the dynamic symbol
 308 // table.
 309
 310 inline bool
 311 Symbol::should_add_dynsym_entry(Symbol_table* symtab) const
 312 {
 313   // If the symbol is used by a dynamic relocation, we need to add it.
 314   if (this->needs_dynsym_entry())
 315     return true;
 316
 317   // If this symbol's section is not added, the symbol need not be added.
 318   // The section may have been GCed.  Note that export_dynamic is being
 319   // overridden here.  This should not be done for shared objects.
 320   if (parameters->options().gc_sections()
 321       && !parameters->options().shared()
 322       && this->source() == Symbol::FROM_OBJECT
 323       && !this->object()->is_dynamic())
 324     {
 325       Relobj* relobj = static_cast<Relobj*>(this->object());
 326       bool is_ordinary;
 327       unsigned int shndx = this->shndx(&is_ordinary);
 328       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
 329           && !relobj->is_section_included(shndx)
 330           && !symtab->is_section_folded(relobj, shndx))
 331         return false;
 332     }
 333
 334   // If the symbol was forced local in a version script, do not add it.
 335   if (this->is_forced_local())
 336     return false;
 337
 338   // If the symbol was forced dynamic in a --dynamic-list file, add it.
 339   if (parameters->options().in_dynamic_list(this->name()))
 340     return true;
 341
 342   // If dynamic-list-data was specified, add any STT_OBJECT.
 343   if (parameters->options().dynamic_list_data()
 344       && !this->is_from_dynobj()
 345       && this->type() == elfcpp::STT_OBJECT)
 346     return true;
 347
 348   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
 349   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
 350   if ((parameters->options().dynamic_list_cpp_new()
 351        || parameters->options().dynamic_list_cpp_typeinfo())
 352       && !this->is_from_dynobj())
 353     {
 354       // TODO(csilvers): We could probably figure out if we're an operator
 355       //                 new/delete or typeinfo without the need to demangle.
 356       char* demangled_name = cplus_demangle(this->name(),
 357                                             DMGL_ANSI | DMGL_PARAMS);
 358       if (demangled_name == NULL)
 359         {
 360           // Not a C++ symbol, so it can't satisfy these flags
 361         }
 362       else if (parameters->options().dynamic_list_cpp_new()
 363                && (strprefix(demangled_name, "operator new")
 364                    || strprefix(demangled_name, "operator delete")))
 365         {
 366           free(demangled_name);
 367           return true;
 368         }
 369       else if (parameters->options().dynamic_list_cpp_typeinfo()
 370                && (strprefix(demangled_name, "typeinfo name for")
 371                    || strprefix(demangled_name, "typeinfo for")))
 372         {
 373           free(demangled_name);
 374           return true;
 375         }
 376       else
 377         free(demangled_name);
 378     }
 379
 380   // If exporting all symbols or building a shared library,
 381   // and the symbol is defined in a regular object and is
 382   // externally visible, we need to add it.
 383   if ((parameters->options().export_dynamic() || parameters->options().shared())
 384       && !this->is_from_dynobj()
 385       && this->is_externally_visible())
 386     return true;
 387
 388   return false;
 389 }
 390
 391 // Return true if the final value of this symbol is known at link
 392 // time.
 393
 394 bool
 395 Symbol::final_value_is_known() const
 396 {
 397   // If we are not generating an executable, then no final values are
 398   // known, since they will change at runtime.
 399   if (parameters->options().output_is_position_independent()
 400       || parameters->options().relocatable())
 401     return false;
 402
 403   // If the symbol is not from an object file, and is not undefined,
 404   // then it is defined, and known.
 405   if (this->source_ != FROM_OBJECT)
 406     {
 407       if (this->source_ != IS_UNDEFINED)
 408         return true;
 409     }
 410   else
 411     {
 412       // If the symbol is from a dynamic object, then the final value
 413       // is not known.
 414       if (this->object()->is_dynamic())
 415         return false;
 416
 417       // If the symbol is not undefined (it is defined or common),
 418       // then the final value is known.
 419       if (!this->is_undefined())
 420         return true;
 421     }
 422
 423   // If the symbol is undefined, then whether the final value is known
 424   // depends on whether we are doing a static link.  If we are doing a
 425   // dynamic link, then the final value could be filled in at runtime.
 426   // This could reasonably be the case for a weak undefined symbol.
 427   return parameters->doing_static_link();
 428 }
 429
 430 // Return the output section where this symbol is defined.
 431
 432 Output_section*
 433 Symbol::output_section() const
 434 {
 435   switch (this->source_)
 436     {
 437     case FROM_OBJECT:
 438       {
 439         unsigned int shndx = this->u_.from_object.shndx;
 440         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
 441           {
 442             gold_assert(!this->u_.from_object.object->is_dynamic());
 443             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
 444             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
 445             return relobj->output_section(shndx);
 446           }
 447         return NULL;
 448       }
 449
 450     case IN_OUTPUT_DATA:
 451       return this->u_.in_output_data.output_data->output_section();
 452
 453     case IN_OUTPUT_SEGMENT:
 454     case IS_CONSTANT:
 455     case IS_UNDEFINED:
 456       return NULL;
 457
 458     default:
 459       gold_unreachable();
 460     }
 461 }
 462
 463 // Set the symbol's output section.  This is used for symbols defined
 464 // in scripts.  This should only be called after the symbol table has
 465 // been finalized.
 466
 467 void
 468 Symbol::set_output_section(Output_section* os)
 469 {
 470   switch (this->source_)
 471     {
 472     case FROM_OBJECT:
 473     case IN_OUTPUT_DATA:
 474       gold_assert(this->output_section() == os);
 475       break;
 476     case IS_CONSTANT:
 477       this->source_ = IN_OUTPUT_DATA;
 478       this->u_.in_output_data.output_data = os;
 479       this->u_.in_output_data.offset_is_from_end = false;
 480       break;
 481     case IN_OUTPUT_SEGMENT:
 482     case IS_UNDEFINED:
 483     default:
 484       gold_unreachable();
 485     }
 486 }
 487
 488 // Class Symbol_table.
 489
 490 Symbol_table::Symbol_table(unsigned int count,
 491                            const Version_script_info& version_script)
 492   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
 493     forwarders_(), commons_(), tls_commons_(), small_commons_(),
 494     large_commons_(), forced_locals_(), warnings_(),
 495     version_script_(version_script), gc_(NULL), icf_(NULL)
 496 {
 497   namepool_.reserve(count);
 498 }
 499
 500 Symbol_table::~Symbol_table()
 501 {
 502 }
 503
 504 // The symbol table key equality function.  This is called with
 505 // Stringpool keys.
 506
 507 inline bool
 508 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
 509                                           const Symbol_table_key& k2) const
 510 {
 511   return k1.first == k2.first && k1.second == k2.second;
 512 }
 513
 514 bool
 515 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
 516 {
 517   return (parameters->options().icf_enabled()
 518           && this->icf_->is_section_folded(obj, shndx));
 519 }
 520
 521 // For symbols that have been listed with -u option, add them to the
 522 // work list to avoid gc'ing them.
 523
 524 void
 525 Symbol_table::gc_mark_undef_symbols(Layout* layout)
 526 {
 527   for (options::String_set::const_iterator p =
 528          parameters->options().undefined_begin();
 529        p != parameters->options().undefined_end();
 530        ++p)
 531     {
 532       const char* name = p->c_str();
 533       Symbol* sym = this->lookup(name);
 534       gold_assert(sym != NULL);
 535       if (sym->source() == Symbol::FROM_OBJECT
 536           && !sym->object()->is_dynamic())
 537         {
 538           Relobj* obj = static_cast<Relobj*>(sym->object());
 539           bool is_ordinary;
 540           unsigned int shndx = sym->shndx(&is_ordinary);
 541           if (is_ordinary)
 542             {
 543               gold_assert(this->gc_ != NULL);
 544               this->gc_->worklist().push(Section_id(obj, shndx));
 545             }
 546         }
 547     }
 548
 549   for (Script_options::referenced_const_iterator p =
 550          layout->script_options()->referenced_begin();
 551        p != layout->script_options()->referenced_end();
 552        ++p)
 553     {
 554       Symbol* sym = this->lookup(p->c_str());
 555       gold_assert(sym != NULL);
 556       if (sym->source() == Symbol::FROM_OBJECT
 557           && !sym->object()->is_dynamic())
 558         {
 559           Relobj* obj = static_cast<Relobj*>(sym->object());
 560           bool is_ordinary;
 561           unsigned int shndx = sym->shndx(&is_ordinary);
 562           if (is_ordinary)
 563             {
 564               gold_assert(this->gc_ != NULL);
 565               this->gc_->worklist().push(Section_id(obj, shndx));
 566             }
 567         }
 568     }
 569 }
 570
 571 void
 572 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
 573 {
 574   if (!sym->is_from_dynobj()
 575       && sym->is_externally_visible())
 576     {
 577       //Add the object and section to the work list.
 578       Relobj* obj = static_cast<Relobj*>(sym->object());
 579       bool is_ordinary;
 580       unsigned int shndx = sym->shndx(&is_ordinary);
 581       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
 582         {
 583           gold_assert(this->gc_!= NULL);
 584           this->gc_->worklist().push(Section_id(obj, shndx));
 585         }
 586     }
 587 }
 588
 589 // When doing garbage collection, keep symbols that have been seen in
 590 // dynamic objects.
 591 inline void
 592 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
 593 {
 594   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
 595       && !sym->object()->is_dynamic())
 596     {
 597       Relobj* obj = static_cast<Relobj*>(sym->object());
 598       bool is_ordinary;
 599       unsigned int shndx = sym->shndx(&is_ordinary);
 600       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
 601         {
 602           gold_assert(this->gc_ != NULL);
 603           this->gc_->worklist().push(Section_id(obj, shndx));
 604         }
 605     }
 606 }
 607
 608 // Make TO a symbol which forwards to FROM.
 609
 610 void
 611 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
 612 {
 613   gold_assert(from != to);
 614   gold_assert(!from->is_forwarder() && !to->is_forwarder());
 615   this->forwarders_[from] = to;
 616   from->set_forwarder();
 617 }
 618
 619 // Resolve the forwards from FROM, returning the real symbol.
 620
 621 Symbol*
 622 Symbol_table::resolve_forwards(const Symbol* from) const
 623 {
 624   gold_assert(from->is_forwarder());
 625   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
 626     this->forwarders_.find(from);
 627   gold_assert(p != this->forwarders_.end());
 628   return p->second;
 629 }
 630
 631 // Look up a symbol by name.
 632
 633 Symbol*
 634 Symbol_table::lookup(const char* name, const char* version) const
 635 {
 636   Stringpool::Key name_key;
 637   name = this->namepool_.find(name, &name_key);
 638   if (name == NULL)
 639     return NULL;
 640
 641   Stringpool::Key version_key = 0;
 642   if (version != NULL)
 643     {
 644       version = this->namepool_.find(version, &version_key);
 645       if (version == NULL)
 646         return NULL;
 647     }
 648
 649   Symbol_table_key key(name_key, version_key);
 650   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
 651   if (p == this->table_.end())
 652     return NULL;
 653   return p->second;
 654 }
 655
 656 // Resolve a Symbol with another Symbol.  This is only used in the
 657 // unusual case where there are references to both an unversioned
 658 // symbol and a symbol with a version, and we then discover that that
 659 // version is the default version.  Because this is unusual, we do
 660 // this the slow way, by converting back to an ELF symbol.
 661
 662 template<int size, bool big_endian>
 663 void
 664 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
 665 {
 666   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
 667   elfcpp::Sym_write<size, big_endian> esym(buf);
 668   // We don't bother to set the st_name or the st_shndx field.
 669   esym.put_st_value(from->value());
 670   esym.put_st_size(from->symsize());
 671   esym.put_st_info(from->binding(), from->type());
 672   esym.put_st_other(from->visibility(), from->nonvis());
 673   bool is_ordinary;
 674   unsigned int shndx = from->shndx(&is_ordinary);
 675   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
 676                 from->version());
 677   if (from->in_reg())
 678     to->set_in_reg();
 679   if (from->in_dyn())
 680     to->set_in_dyn();
 681   if (parameters->options().gc_sections())
 682     this->gc_mark_dyn_syms(to);
 683 }
 684
 685 // Record that a symbol is forced to be local by a version script or
 686 // by visibility.
 687
 688 void
 689 Symbol_table::force_local(Symbol* sym)
 690 {
 691   if (!sym->is_defined() && !sym->is_common())
 692     return;
 693   if (sym->is_forced_local())
 694     {
 695       // We already got this one.
 696       return;
 697     }
 698   sym->set_is_forced_local();
 699   this->forced_locals_.push_back(sym);
 700 }
 701
 702 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
 703 // is only called for undefined symbols, when at least one --wrap
 704 // option was used.
 705
 706 const char*
 707 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
 708 {
 709   // For some targets, we need to ignore a specific character when
 710   // wrapping, and add it back later.
 711   char prefix = '\0';
 712   if (name[0] == parameters->target().wrap_char())
 713     {
 714       prefix = name[0];
 715       ++name;
 716     }
 717
 718   if (parameters->options().is_wrap(name))
 719     {
 720       // Turn NAME into __wrap_NAME.
 721       std::string s;
 722       if (prefix != '\0')
 723         s += prefix;
 724       s += "__wrap_";
 725       s += name;
 726
 727       // This will give us both the old and new name in NAMEPOOL_, but
 728       // that is OK.  Only the versions we need will wind up in the
 729       // real string table in the output file.
 730       return this->namepool_.add(s.c_str(), true, name_key);
 731     }
 732
 733   const char* const real_prefix = "__real_";
 734   const size_t real_prefix_length = strlen(real_prefix);
 735   if (strncmp(name, real_prefix, real_prefix_length) == 0
 736       && parameters->options().is_wrap(name + real_prefix_length))
 737     {
 738       // Turn __real_NAME into NAME.
 739       std::string s;
 740       if (prefix != '\0')
 741         s += prefix;
 742       s += name + real_prefix_length;
 743       return this->namepool_.add(s.c_str(), true, name_key);
 744     }
 745
 746   return name;
 747 }
 748
 749 // This is called when we see a symbol NAME/VERSION, and the symbol
 750 // already exists in the symbol table, and VERSION is marked as being
 751 // the default version.  SYM is the NAME/VERSION symbol we just added.
 752 // DEFAULT_IS_NEW is true if this is the first time we have seen the
 753 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
 754
 755 template<int size, bool big_endian>
 756 void
 757 Symbol_table::define_default_version(Sized_symbol<size>* sym,
 758                                      bool default_is_new,
 759                                      Symbol_table_type::iterator pdef)
 760 {
 761   if (default_is_new)
 762     {
 763       // This is the first time we have seen NAME/NULL.  Make
 764       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
 765       // version.
 766       pdef->second = sym;
 767       sym->set_is_default();
 768     }
 769   else if (pdef->second == sym)
 770     {
 771       // NAME/NULL already points to NAME/VERSION.  Don't mark the
 772       // symbol as the default if it is not already the default.
 773     }
 774   else
 775     {
 776       // This is the unfortunate case where we already have entries
 777       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
 778       // NAME/VERSION where VERSION is the default version.  We have
 779       // already resolved this new symbol with the existing
 780       // NAME/VERSION symbol.
 781
 782       // It's possible that NAME/NULL and NAME/VERSION are both
 783       // defined in regular objects.  This can only happen if one
 784       // object file defines foo and another defines foo@@ver.  This
 785       // is somewhat obscure, but we call it a multiple definition
 786       // error.
 787
 788       // It's possible that NAME/NULL actually has a version, in which
 789       // case it won't be the same as VERSION.  This happens with
 790       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
 791       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
 792       // then see an unadorned t2_2 in an object file and give it
 793       // version VER1 from the version script.  This looks like a
 794       // default definition for VER1, so it looks like we should merge
 795       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
 796       // not obvious that this is an error, either.  So we just punt.
 797
 798       // If one of the symbols has non-default visibility, and the
 799       // other is defined in a shared object, then they are different
 800       // symbols.
 801
 802       // Otherwise, we just resolve the symbols as though they were
 803       // the same.
 804
 805       if (pdef->second->version() != NULL)
 806         gold_assert(pdef->second->version() != sym->version());
 807       else if (sym->visibility() != elfcpp::STV_DEFAULT
 808                && pdef->second->is_from_dynobj())
 809         ;
 810       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
 811                && sym->is_from_dynobj())
 812         ;
 813       else
 814         {
 815           const Sized_symbol<size>* symdef;
 816           symdef = this->get_sized_symbol<size>(pdef->second);
 817           Symbol_table::resolve<size, big_endian>(sym, symdef);
 818           this->make_forwarder(pdef->second, sym);
 819           pdef->second = sym;
 820           sym->set_is_default();
 821         }
 822     }
 823 }
 824
 825 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
 826 // name and VERSION is the version; both are canonicalized.  DEF is
 827 // whether this is the default version.  ST_SHNDX is the symbol's
 828 // section index; IS_ORDINARY is whether this is a normal section
 829 // rather than a special code.
 830
 831 // If IS_DEFAULT_VERSION is true, then this is the definition of a
 832 // default version of a symbol.  That means that any lookup of
 833 // NAME/NULL and any lookup of NAME/VERSION should always return the
 834 // same symbol.  This is obvious for references, but in particular we
 835 // want to do this for definitions: overriding NAME/NULL should also
 836 // override NAME/VERSION.  If we don't do that, it would be very hard
 837 // to override functions in a shared library which uses versioning.
 838
 839 // We implement this by simply making both entries in the hash table
 840 // point to the same Symbol structure.  That is easy enough if this is
 841 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
 842 // that we have seen both already, in which case they will both have
 843 // independent entries in the symbol table.  We can't simply change
 844 // the symbol table entry, because we have pointers to the entries
 845 // attached to the object files.  So we mark the entry attached to the
 846 // object file as a forwarder, and record it in the forwarders_ map.
 847 // Note that entries in the hash table will never be marked as
 848 // forwarders.
 849 //
 850 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
 851 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
 852 // for a special section code.  ST_SHNDX may be modified if the symbol
 853 // is defined in a section being discarded.
 854
 855 template<int size, bool big_endian>
 856 Sized_symbol<size>*
 857 Symbol_table::add_from_object(Object* object,
 858                               const char* name,
 859                               Stringpool::Key name_key,
 860                               const char* version,
 861                               Stringpool::Key version_key,
 862                               bool is_default_version,
 863                               const elfcpp::Sym<size, big_endian>& sym,
 864                               unsigned int st_shndx,
 865                               bool is_ordinary,
 866                               unsigned int orig_st_shndx)
 867 {
 868   // Print a message if this symbol is being traced.
 869   if (parameters->options().is_trace_symbol(name))
 870     {
 871       if (orig_st_shndx == elfcpp::SHN_UNDEF)
 872         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
 873       else
 874         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
 875     }
 876
 877   // For an undefined symbol, we may need to adjust the name using
 878   // --wrap.
 879   if (orig_st_shndx == elfcpp::SHN_UNDEF
 880       && parameters->options().any_wrap())
 881     {
 882       const char* wrap_name = this->wrap_symbol(name, &name_key);
 883       if (wrap_name != name)
 884         {
 885           // If we see a reference to malloc with version GLIBC_2.0,
 886           // and we turn it into a reference to __wrap_malloc, then we
 887           // discard the version number.  Otherwise the user would be
 888           // required to specify the correct version for
 889           // __wrap_malloc.
 890           version = NULL;
 891           version_key = 0;
 892           name = wrap_name;
 893         }
 894     }
 895
 896   Symbol* const snull = NULL;
 897   std::pair<typename Symbol_table_type::iterator, bool> ins =
 898     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
 899                                        snull));
 900
 901   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
 902     std::make_pair(this->table_.end(), false);
 903   if (is_default_version)
 904     {
 905       const Stringpool::Key vnull_key = 0;
 906       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
 907                                                                      vnull_key),
 908                                                       snull));
 909     }
 910
 911   // ins.first: an iterator, which is a pointer to a pair.
 912   // ins.first->first: the key (a pair of name and version).
 913   // ins.first->second: the value (Symbol*).
 914   // ins.second: true if new entry was inserted, false if not.
 915
 916   Sized_symbol<size>* ret;
 917   bool was_undefined;
 918   bool was_common;
 919   if (!ins.second)
 920     {
 921       // We already have an entry for NAME/VERSION.
 922       ret = this->get_sized_symbol<size>(ins.first->second);
 923       gold_assert(ret != NULL);
 924
 925       was_undefined = ret->is_undefined();
 926       was_common = ret->is_common();
 927
 928       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
 929                     version);
 930       if (parameters->options().gc_sections())
 931         this->gc_mark_dyn_syms(ret);
 932
 933       if (is_default_version)
 934         this->define_default_version<size, big_endian>(ret, insdefault.second,
 935                                                        insdefault.first);
 936     }
 937   else
 938     {
 939       // This is the first time we have seen NAME/VERSION.
 940       gold_assert(ins.first->second == NULL);
 941
 942       if (is_default_version && !insdefault.second)
 943         {
 944           // We already have an entry for NAME/NULL.  If we override
 945           // it, then change it to NAME/VERSION.
 946           ret = this->get_sized_symbol<size>(insdefault.first->second);
 947
 948           was_undefined = ret->is_undefined();
 949           was_common = ret->is_common();
 950
 951           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
 952                         version);
 953           if (parameters->options().gc_sections())
 954             this->gc_mark_dyn_syms(ret);
 955           ins.first->second = ret;
 956         }
 957       else
 958         {
 959           was_undefined = false;
 960           was_common = false;
 961
 962           Sized_target<size, big_endian>* target =
 963             parameters->sized_target<size, big_endian>();
 964           if (!target->has_make_symbol())
 965             ret = new Sized_symbol<size>();
 966           else
 967             {
 968               ret = target->make_symbol();
 969               if (ret == NULL)
 970                 {
 971                   // This means that we don't want a symbol table
 972                   // entry after all.
 973                   if (!is_default_version)
 974                     this->table_.erase(ins.first);
 975                   else
 976                     {
 977                       this->table_.erase(insdefault.first);
 978                       // Inserting INSDEFAULT invalidated INS.
 979                       this->table_.erase(std::make_pair(name_key,
 980                                                         version_key));
 981                     }
 982                   return NULL;
 983                 }
 984             }
 985
 986           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
 987
 988           ins.first->second = ret;
 989           if (is_default_version)
 990             {
 991               // This is the first time we have seen NAME/NULL.  Point
 992               // it at the new entry for NAME/VERSION.
 993               gold_assert(insdefault.second);
 994               insdefault.first->second = ret;
 995             }
 996         }
 997
 998       if (is_default_version)
 999         ret->set_is_default();
1000     }
1001
1002   // Record every time we see a new undefined symbol, to speed up
1003   // archive groups.
1004   if (!was_undefined && ret->is_undefined())
1005     {
1006       ++this->saw_undefined_;
1007       if (parameters->options().has_plugins())
1008         parameters->options().plugins()->new_undefined_symbol(ret);
1009     }
1010
1011   // Keep track of common symbols, to speed up common symbol
1012   // allocation.
1013   if (!was_common && ret->is_common())
1014     {
1015       if (ret->type() == elfcpp::STT_TLS)
1016         this->tls_commons_.push_back(ret);
1017       else if (!is_ordinary
1018                && st_shndx == parameters->target().small_common_shndx())
1019         this->small_commons_.push_back(ret);
1020       else if (!is_ordinary
1021                && st_shndx == parameters->target().large_common_shndx())
1022         this->large_commons_.push_back(ret);
1023       else
1024         this->commons_.push_back(ret);
1025     }
1026
1027   // If we're not doing a relocatable link, then any symbol with
1028   // hidden or internal visibility is local.
1029   if ((ret->visibility() == elfcpp::STV_HIDDEN
1030        || ret->visibility() == elfcpp::STV_INTERNAL)
1031       && (ret->binding() == elfcpp::STB_GLOBAL
1032           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1033           || ret->binding() == elfcpp::STB_WEAK)
1034       && !parameters->options().relocatable())
1035     this->force_local(ret);
1036
1037   return ret;
1038 }
1039
1040 // Add all the symbols in a relocatable object to the hash table.
1041
1042 template<int size, bool big_endian>
1043 void
1044 Symbol_table::add_from_relobj(
1045     Sized_relobj<size, big_endian>* relobj,
1046     const unsigned char* syms,
1047     size_t count,
1048     size_t symndx_offset,
1049     const char* sym_names,
1050     size_t sym_name_size,
1051     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1052     size_t* defined)
1053 {
1054   *defined = 0;
1055
1056   gold_assert(size == parameters->target().get_size());
1057
1058   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1059
1060   const bool just_symbols = relobj->just_symbols();
1061
1062   const unsigned char* p = syms;
1063   for (size_t i = 0; i < count; ++i, p += sym_size)
1064     {
1065       (*sympointers)[i] = NULL;
1066
1067       elfcpp::Sym<size, big_endian> sym(p);
1068
1069       unsigned int st_name = sym.get_st_name();
1070       if (st_name >= sym_name_size)
1071         {
1072           relobj->error(_("bad global symbol name offset %u at %zu"),
1073                         st_name, i);
1074           continue;
1075         }
1076
1077       const char* name = sym_names + st_name;
1078
1079       bool is_ordinary;
1080       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1081                                                        sym.get_st_shndx(),
1082                                                        &is_ordinary);
1083       unsigned int orig_st_shndx = st_shndx;
1084       if (!is_ordinary)
1085         orig_st_shndx = elfcpp::SHN_UNDEF;
1086
1087       if (st_shndx != elfcpp::SHN_UNDEF)
1088         ++*defined;
1089
1090       // A symbol defined in a section which we are not including must
1091       // be treated as an undefined symbol.
1092       bool is_defined_in_discarded_section = false;
1093       if (st_shndx != elfcpp::SHN_UNDEF
1094           && is_ordinary
1095           && !relobj->is_section_included(st_shndx)
1096           && !this->is_section_folded(relobj, st_shndx))
1097         {
1098           st_shndx = elfcpp::SHN_UNDEF;
1099           is_defined_in_discarded_section = true;
1100         }
1101
1102       // In an object file, an '@' in the name separates the symbol
1103       // name from the version name.  If there are two '@' characters,
1104       // this is the default version.
1105       const char* ver = strchr(name, '@');
1106       Stringpool::Key ver_key = 0;
1107       int namelen = 0;
1108       // IS_DEFAULT_VERSION: is the version default?
1109       // IS_FORCED_LOCAL: is the symbol forced local?
1110       bool is_default_version = false;
1111       bool is_forced_local = false;
1112
1113       if (ver != NULL)
1114         {
1115           // The symbol name is of the form foo@VERSION or foo@@VERSION
1116           namelen = ver - name;
1117           ++ver;
1118           if (*ver == '@')
1119             {
1120               is_default_version = true;
1121               ++ver;
1122             }
1123           ver = this->namepool_.add(ver, true, &ver_key);
1124         }
1125       // We don't want to assign a version to an undefined symbol,
1126       // even if it is listed in the version script.  FIXME: What
1127       // about a common symbol?
1128       else
1129         {
1130           namelen = strlen(name);
1131           if (!this->version_script_.empty()
1132               && st_shndx != elfcpp::SHN_UNDEF)
1133             {
1134               // The symbol name did not have a version, but the
1135               // version script may assign a version anyway.
1136               std::string version;
1137               bool is_global;
1138               if (this->version_script_.get_symbol_version(name, &version,
1139                                                            &is_global))
1140                 {
1141                   if (!is_global)
1142                     is_forced_local = true;
1143                   else if (!version.empty())
1144                     {
1145                       ver = this->namepool_.add_with_length(version.c_str(),
1146                                                             version.length(),
1147                                                             true,
1148                                                             &ver_key);
1149                       is_default_version = true;
1150                     }
1151                 }
1152             }
1153         }
1154
1155       elfcpp::Sym<size, big_endian>* psym = &sym;
1156       unsigned char symbuf[sym_size];
1157       elfcpp::Sym<size, big_endian> sym2(symbuf);
1158       if (just_symbols)
1159         {
1160           memcpy(symbuf, p, sym_size);
1161           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1162           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1163             {
1164               // Symbol values in object files are section relative.
1165               // This is normally what we want, but since here we are
1166               // converting the symbol to absolute we need to add the
1167               // section address.  The section address in an object
1168               // file is normally zero, but people can use a linker
1169               // script to change it.
1170               sw.put_st_value(sym.get_st_value()
1171                               + relobj->section_address(orig_st_shndx));
1172             }
1173           st_shndx = elfcpp::SHN_ABS;
1174           is_ordinary = false;
1175           psym = &sym2;
1176         }
1177
1178       // Fix up visibility if object has no-export set.
1179       if (relobj->no_export()
1180           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1181         {
1182           // We may have copied symbol already above.
1183           if (psym != &sym2)
1184             {
1185               memcpy(symbuf, p, sym_size);
1186               psym = &sym2;
1187             }
1188
1189           elfcpp::STV visibility = sym2.get_st_visibility();
1190           if (visibility == elfcpp::STV_DEFAULT
1191               || visibility == elfcpp::STV_PROTECTED)
1192             {
1193               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1194               unsigned char nonvis = sym2.get_st_nonvis();
1195               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1196             }
1197         }
1198
1199       Stringpool::Key name_key;
1200       name = this->namepool_.add_with_length(name, namelen, true,
1201                                              &name_key);
1202
1203       Sized_symbol<size>* res;
1204       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1205                                   is_default_version, *psym, st_shndx,
1206                                   is_ordinary, orig_st_shndx);
1207
1208       // If building a shared library using garbage collection, do not
1209       // treat externally visible symbols as garbage.
1210       if (parameters->options().gc_sections()
1211           && parameters->options().shared())
1212         this->gc_mark_symbol_for_shlib(res);
1213
1214       if (is_forced_local)
1215         this->force_local(res);
1216
1217       if (is_defined_in_discarded_section)
1218         res->set_is_defined_in_discarded_section();
1219
1220       (*sympointers)[i] = res;
1221     }
1222 }
1223
1224 // Add a symbol from a plugin-claimed file.
1225
1226 template<int size, bool big_endian>
1227 Symbol*
1228 Symbol_table::add_from_pluginobj(
1229     Sized_pluginobj<size, big_endian>* obj,
1230     const char* name,
1231     const char* ver,
1232     elfcpp::Sym<size, big_endian>* sym)
1233 {
1234   unsigned int st_shndx = sym->get_st_shndx();
1235   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1236
1237   Stringpool::Key ver_key = 0;
1238   bool is_default_version = false;
1239   bool is_forced_local = false;
1240
1241   if (ver != NULL)
1242     {
1243       ver = this->namepool_.add(ver, true, &ver_key);
1244     }
1245   // We don't want to assign a version to an undefined symbol,
1246   // even if it is listed in the version script.  FIXME: What
1247   // about a common symbol?
1248   else
1249     {
1250       if (!this->version_script_.empty()
1251           && st_shndx != elfcpp::SHN_UNDEF)
1252         {
1253           // The symbol name did not have a version, but the
1254           // version script may assign a version anyway.
1255           std::string version;
1256           bool is_global;
1257           if (this->version_script_.get_symbol_version(name, &version,
1258                                                        &is_global))
1259             {
1260               if (!is_global)
1261                 is_forced_local = true;
1262               else if (!version.empty())
1263                 {
1264                   ver = this->namepool_.add_with_length(version.c_str(),
1265                                                         version.length(),
1266                                                         true,
1267                                                         &ver_key);
1268                   is_default_version = true;
1269                 }
1270             }
1271         }
1272     }
1273
1274   Stringpool::Key name_key;
1275   name = this->namepool_.add(name, true, &name_key);
1276
1277   Sized_symbol<size>* res;
1278   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1279                               is_default_version, *sym, st_shndx,
1280                               is_ordinary, st_shndx);
1281
1282   if (is_forced_local)
1283     this->force_local(res);
1284
1285   return res;
1286 }
1287
1288 // Add all the symbols in a dynamic object to the hash table.
1289
1290 template<int size, bool big_endian>
1291 void
1292 Symbol_table::add_from_dynobj(
1293     Sized_dynobj<size, big_endian>* dynobj,
1294     const unsigned char* syms,
1295     size_t count,
1296     const char* sym_names,
1297     size_t sym_name_size,
1298     const unsigned char* versym,
1299     size_t versym_size,
1300     const std::vector<const char*>* version_map,
1301     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1302     size_t* defined)
1303 {
1304   *defined = 0;
1305
1306   gold_assert(size == parameters->target().get_size());
1307
1308   if (dynobj->just_symbols())
1309     {
1310       gold_error(_("--just-symbols does not make sense with a shared object"));
1311       return;
1312     }
1313
1314   if (versym != NULL && versym_size / 2 < count)
1315     {
1316       dynobj->error(_("too few symbol versions"));
1317       return;
1318     }
1319
1320   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1321
1322   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1323   // weak aliases.  This is necessary because if the dynamic object
1324   // provides the same variable under two names, one of which is a
1325   // weak definition, and the regular object refers to the weak
1326   // definition, we have to put both the weak definition and the
1327   // strong definition into the dynamic symbol table.  Given a weak
1328   // definition, the only way that we can find the corresponding
1329   // strong definition, if any, is to search the symbol table.
1330   std::vector<Sized_symbol<size>*> object_symbols;
1331
1332   const unsigned char* p = syms;
1333   const unsigned char* vs = versym;
1334   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1335     {
1336       elfcpp::Sym<size, big_endian> sym(p);
1337
1338       if (sympointers != NULL)
1339         (*sympointers)[i] = NULL;
1340
1341       // Ignore symbols with local binding or that have
1342       // internal or hidden visibility.
1343       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1344           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1345           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1346         continue;
1347
1348       // A protected symbol in a shared library must be treated as a
1349       // normal symbol when viewed from outside the shared library.
1350       // Implement this by overriding the visibility here.
1351       elfcpp::Sym<size, big_endian>* psym = &sym;
1352       unsigned char symbuf[sym_size];
1353       elfcpp::Sym<size, big_endian> sym2(symbuf);
1354       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1355         {
1356           memcpy(symbuf, p, sym_size);
1357           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1358           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1359           psym = &sym2;
1360         }
1361
1362       unsigned int st_name = psym->get_st_name();
1363       if (st_name >= sym_name_size)
1364         {
1365           dynobj->error(_("bad symbol name offset %u at %zu"),
1366                         st_name, i);
1367           continue;
1368         }
1369
1370       const char* name = sym_names + st_name;
1371
1372       bool is_ordinary;
1373       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1374                                                        &is_ordinary);
1375
1376       if (st_shndx != elfcpp::SHN_UNDEF)
1377         ++*defined;
1378
1379       Sized_symbol<size>* res;
1380
1381       if (versym == NULL)
1382         {
1383           Stringpool::Key name_key;
1384           name = this->namepool_.add(name, true, &name_key);
1385           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1386                                       false, *psym, st_shndx, is_ordinary,
1387                                       st_shndx);
1388         }
1389       else
1390         {
1391           // Read the version information.
1392
1393           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1394
1395           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1396           v &= elfcpp::VERSYM_VERSION;
1397
1398           // The Sun documentation says that V can be VER_NDX_LOCAL,
1399           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1400           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1401           // The old GNU linker will happily generate VER_NDX_LOCAL
1402           // for an undefined symbol.  I don't know what the Sun
1403           // linker will generate.
1404
1405           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1406               && st_shndx != elfcpp::SHN_UNDEF)
1407             {
1408               // This symbol should not be visible outside the object.
1409               continue;
1410             }
1411
1412           // At this point we are definitely going to add this symbol.
1413           Stringpool::Key name_key;
1414           name = this->namepool_.add(name, true, &name_key);
1415
1416           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1417               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1418             {
1419               // This symbol does not have a version.
1420               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1421                                           false, *psym, st_shndx, is_ordinary,
1422                                           st_shndx);
1423             }
1424           else
1425             {
1426               if (v >= version_map->size())
1427                 {
1428                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1429                                 i, v);
1430                   continue;
1431                 }
1432
1433               const char* version = (*version_map)[v];
1434               if (version == NULL)
1435                 {
1436                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1437                                 i, v);
1438                   continue;
1439                 }
1440
1441               Stringpool::Key version_key;
1442               version = this->namepool_.add(version, true, &version_key);
1443
1444               // If this is an absolute symbol, and the version name
1445               // and symbol name are the same, then this is the
1446               // version definition symbol.  These symbols exist to
1447               // support using -u to pull in particular versions.  We
1448               // do not want to record a version for them.
1449               if (st_shndx == elfcpp::SHN_ABS
1450                   && !is_ordinary
1451                   && name_key == version_key)
1452                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1453                                             false, *psym, st_shndx, is_ordinary,
1454                                             st_shndx);
1455               else
1456                 {
1457                   const bool is_default_version =
1458                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1459                   res = this->add_from_object(dynobj, name, name_key, version,
1460                                               version_key, is_default_version,
1461                                               *psym, st_shndx,
1462                                               is_ordinary, st_shndx);
1463                 }
1464             }
1465         }
1466
1467       // Note that it is possible that RES was overridden by an
1468       // earlier object, in which case it can't be aliased here.
1469       if (st_shndx != elfcpp::SHN_UNDEF
1470           && is_ordinary
1471           && psym->get_st_type() == elfcpp::STT_OBJECT
1472           && res->source() == Symbol::FROM_OBJECT
1473           && res->object() == dynobj)
1474         object_symbols.push_back(res);
1475
1476       if (sympointers != NULL)
1477         (*sympointers)[i] = res;
1478     }
1479
1480   this->record_weak_aliases(&object_symbols);
1481 }
1482
1483 // This is used to sort weak aliases.  We sort them first by section
1484 // index, then by offset, then by weak ahead of strong.
1485
1486 template<int size>
1487 class Weak_alias_sorter
1488 {
1489  public:
1490   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1491 };
1492
1493 template<int size>
1494 bool
1495 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1496                                     const Sized_symbol<size>* s2) const
1497 {
1498   bool is_ordinary;
1499   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1500   gold_assert(is_ordinary);
1501   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1502   gold_assert(is_ordinary);
1503   if (s1_shndx != s2_shndx)
1504     return s1_shndx < s2_shndx;
1505
1506   if (s1->value() != s2->value())
1507     return s1->value() < s2->value();
1508   if (s1->binding() != s2->binding())
1509     {
1510       if (s1->binding() == elfcpp::STB_WEAK)
1511         return true;
1512       if (s2->binding() == elfcpp::STB_WEAK)
1513         return false;
1514     }
1515   return std::string(s1->name()) < std::string(s2->name());
1516 }
1517
1518 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1519 // for any weak aliases, and record them so that if we add the weak
1520 // alias to the dynamic symbol table, we also add the corresponding
1521 // strong symbol.
1522
1523 template<int size>
1524 void
1525 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1526 {
1527   // Sort the vector by section index, then by offset, then by weak
1528   // ahead of strong.
1529   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1530
1531   // Walk through the vector.  For each weak definition, record
1532   // aliases.
1533   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1534          symbols->begin();
1535        p != symbols->end();
1536        ++p)
1537     {
1538       if ((*p)->binding() != elfcpp::STB_WEAK)
1539         continue;
1540
1541       // Build a circular list of weak aliases.  Each symbol points to
1542       // the next one in the circular list.
1543
1544       Sized_symbol<size>* from_sym = *p;
1545       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1546       for (q = p + 1; q != symbols->end(); ++q)
1547         {
1548           bool dummy;
1549           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1550               || (*q)->value() != from_sym->value())
1551             break;
1552
1553           this->weak_aliases_[from_sym] = *q;
1554           from_sym->set_has_alias();
1555           from_sym = *q;
1556         }
1557
1558       if (from_sym != *p)
1559         {
1560           this->weak_aliases_[from_sym] = *p;
1561           from_sym->set_has_alias();
1562         }
1563
1564       p = q - 1;
1565     }
1566 }
1567
1568 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1569 // true, then only create the symbol if there is a reference to it.
1570 // If this does not return NULL, it sets *POLDSYM to the existing
1571 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1572 // resolve the newly created symbol to the old one.  This
1573 // canonicalizes *PNAME and *PVERSION.
1574
1575 template<int size, bool big_endian>
1576 Sized_symbol<size>*
1577 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1578                                     bool only_if_ref,
1579                                     Sized_symbol<size>** poldsym,
1580                                     bool* resolve_oldsym)
1581 {
1582   *resolve_oldsym = false;
1583
1584   // If the caller didn't give us a version, see if we get one from
1585   // the version script.
1586   std::string v;
1587   bool is_default_version = false;
1588   if (*pversion == NULL)
1589     {
1590       bool is_global;
1591       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1592         {
1593           if (is_global && !v.empty())
1594             {
1595               *pversion = v.c_str();
1596               // If we get the version from a version script, then we
1597               // are also the default version.
1598               is_default_version = true;
1599             }
1600         }
1601     }
1602
1603   Symbol* oldsym;
1604   Sized_symbol<size>* sym;
1605
1606   bool add_to_table = false;
1607   typename Symbol_table_type::iterator add_loc = this->table_.end();
1608   bool add_def_to_table = false;
1609   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1610
1611   if (only_if_ref)
1612     {
1613       oldsym = this->lookup(*pname, *pversion);
1614       if (oldsym == NULL && is_default_version)
1615         oldsym = this->lookup(*pname, NULL);
1616       if (oldsym == NULL || !oldsym->is_undefined())
1617         return NULL;
1618
1619       *pname = oldsym->name();
1620       if (!is_default_version)
1621         *pversion = oldsym->version();
1622     }
1623   else
1624     {
1625       // Canonicalize NAME and VERSION.
1626       Stringpool::Key name_key;
1627       *pname = this->namepool_.add(*pname, true, &name_key);
1628
1629       Stringpool::Key version_key = 0;
1630       if (*pversion != NULL)
1631         *pversion = this->namepool_.add(*pversion, true, &version_key);
1632
1633       Symbol* const snull = NULL;
1634       std::pair<typename Symbol_table_type::iterator, bool> ins =
1635         this->table_.insert(std::make_pair(std::make_pair(name_key,
1636                                                           version_key),
1637                                            snull));
1638
1639       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1640         std::make_pair(this->table_.end(), false);
1641       if (is_default_version)
1642         {
1643           const Stringpool::Key vnull = 0;
1644           insdefault =
1645             this->table_.insert(std::make_pair(std::make_pair(name_key,
1646                                                               vnull),
1647                                                snull));
1648         }
1649
1650       if (!ins.second)
1651         {
1652           // We already have a symbol table entry for NAME/VERSION.
1653           oldsym = ins.first->second;
1654           gold_assert(oldsym != NULL);
1655
1656           if (is_default_version)
1657             {
1658               Sized_symbol<size>* soldsym =
1659                 this->get_sized_symbol<size>(oldsym);
1660               this->define_default_version<size, big_endian>(soldsym,
1661                                                              insdefault.second,
1662                                                              insdefault.first);
1663             }
1664         }
1665       else
1666         {
1667           // We haven't seen this symbol before.
1668           gold_assert(ins.first->second == NULL);
1669
1670           add_to_table = true;
1671           add_loc = ins.first;
1672
1673           if (is_default_version && !insdefault.second)
1674             {
1675               // We are adding NAME/VERSION, and it is the default
1676               // version.  We already have an entry for NAME/NULL.
1677               oldsym = insdefault.first->second;
1678               *resolve_oldsym = true;
1679             }
1680           else
1681             {
1682               oldsym = NULL;
1683
1684               if (is_default_version)
1685                 {
1686                   add_def_to_table = true;
1687                   add_def_loc = insdefault.first;
1688                 }
1689             }
1690         }
1691     }
1692
1693   const Target& target = parameters->target();
1694   if (!target.has_make_symbol())
1695     sym = new Sized_symbol<size>();
1696   else
1697     {
1698       Sized_target<size, big_endian>* sized_target =
1699         parameters->sized_target<size, big_endian>();
1700       sym = sized_target->make_symbol();
1701       if (sym == NULL)
1702         return NULL;
1703     }
1704
1705   if (add_to_table)
1706     add_loc->second = sym;
1707   else
1708     gold_assert(oldsym != NULL);
1709
1710   if (add_def_to_table)
1711     add_def_loc->second = sym;
1712
1713   *poldsym = this->get_sized_symbol<size>(oldsym);
1714
1715   return sym;
1716 }
1717
1718 // Define a symbol based on an Output_data.
1719
1720 Symbol*
1721 Symbol_table::define_in_output_data(const char* name,
1722                                     const char* version,
1723                                     Defined defined,
1724                                     Output_data* od,
1725                                     uint64_t value,
1726                                     uint64_t symsize,
1727                                     elfcpp::STT type,
1728                                     elfcpp::STB binding,
1729                                     elfcpp::STV visibility,
1730                                     unsigned char nonvis,
1731                                     bool offset_is_from_end,
1732                                     bool only_if_ref)
1733 {
1734   if (parameters->target().get_size() == 32)
1735     {
1736 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1737       return this->do_define_in_output_data<32>(name, version, defined, od,
1738                                                 value, symsize, type, binding,
1739                                                 visibility, nonvis,
1740                                                 offset_is_from_end,
1741                                                 only_if_ref);
1742 #else
1743       gold_unreachable();
1744 #endif
1745     }
1746   else if (parameters->target().get_size() == 64)
1747     {
1748 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1749       return this->do_define_in_output_data<64>(name, version, defined, od,
1750                                                 value, symsize, type, binding,
1751                                                 visibility, nonvis,
1752                                                 offset_is_from_end,
1753                                                 only_if_ref);
1754 #else
1755       gold_unreachable();
1756 #endif
1757     }
1758   else
1759     gold_unreachable();
1760 }
1761
1762 // Define a symbol in an Output_data, sized version.
1763
1764 template<int size>
1765 Sized_symbol<size>*
1766 Symbol_table::do_define_in_output_data(
1767     const char* name,
1768     const char* version,
1769     Defined defined,
1770     Output_data* od,
1771     typename elfcpp::Elf_types<size>::Elf_Addr value,
1772     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1773     elfcpp::STT type,
1774     elfcpp::STB binding,
1775     elfcpp::STV visibility,
1776     unsigned char nonvis,
1777     bool offset_is_from_end,
1778     bool only_if_ref)
1779 {
1780   Sized_symbol<size>* sym;
1781   Sized_symbol<size>* oldsym;
1782   bool resolve_oldsym;
1783
1784   if (parameters->target().is_big_endian())
1785     {
1786 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1787       sym = this->define_special_symbol<size, true>(&name, &version,
1788                                                     only_if_ref, &oldsym,
1789                                                     &resolve_oldsym);
1790 #else
1791       gold_unreachable();
1792 #endif
1793     }
1794   else
1795     {
1796 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1797       sym = this->define_special_symbol<size, false>(&name, &version,
1798                                                      only_if_ref, &oldsym,
1799                                                      &resolve_oldsym);
1800 #else
1801       gold_unreachable();
1802 #endif
1803     }
1804
1805   if (sym == NULL)
1806     return NULL;
1807
1808   sym->init_output_data(name, version, od, value, symsize, type, binding,
1809                         visibility, nonvis, offset_is_from_end);
1810
1811   if (oldsym == NULL)
1812     {
1813       if (binding == elfcpp::STB_LOCAL
1814           || this->version_script_.symbol_is_local(name))
1815         this->force_local(sym);
1816       else if (version != NULL)
1817         sym->set_is_default();
1818       return sym;
1819     }
1820
1821   if (Symbol_table::should_override_with_special(oldsym, defined))
1822     this->override_with_special(oldsym, sym);
1823
1824   if (resolve_oldsym)
1825     return sym;
1826   else
1827     {
1828       delete sym;
1829       return oldsym;
1830     }
1831 }
1832
1833 // Define a symbol based on an Output_segment.
1834
1835 Symbol*
1836 Symbol_table::define_in_output_segment(const char* name,
1837                                        const char* version,
1838                                        Defined defined,
1839                                        Output_segment* os,
1840                                        uint64_t value,
1841                                        uint64_t symsize,
1842                                        elfcpp::STT type,
1843                                        elfcpp::STB binding,
1844                                        elfcpp::STV visibility,
1845                                        unsigned char nonvis,
1846                                        Symbol::Segment_offset_base offset_base,
1847                                        bool only_if_ref)
1848 {
1849   if (parameters->target().get_size() == 32)
1850     {
1851 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1852       return this->do_define_in_output_segment<32>(name, version, defined, os,
1853                                                    value, symsize, type,
1854                                                    binding, visibility, nonvis,
1855                                                    offset_base, only_if_ref);
1856 #else
1857       gold_unreachable();
1858 #endif
1859     }
1860   else if (parameters->target().get_size() == 64)
1861     {
1862 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1863       return this->do_define_in_output_segment<64>(name, version, defined, os,
1864                                                    value, symsize, type,
1865                                                    binding, visibility, nonvis,
1866                                                    offset_base, only_if_ref);
1867 #else
1868       gold_unreachable();
1869 #endif
1870     }
1871   else
1872     gold_unreachable();
1873 }
1874
1875 // Define a symbol in an Output_segment, sized version.
1876
1877 template<int size>
1878 Sized_symbol<size>*
1879 Symbol_table::do_define_in_output_segment(
1880     const char* name,
1881     const char* version,
1882     Defined defined,
1883     Output_segment* os,
1884     typename elfcpp::Elf_types<size>::Elf_Addr value,
1885     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1886     elfcpp::STT type,
1887     elfcpp::STB binding,
1888     elfcpp::STV visibility,
1889     unsigned char nonvis,
1890     Symbol::Segment_offset_base offset_base,
1891     bool only_if_ref)
1892 {
1893   Sized_symbol<size>* sym;
1894   Sized_symbol<size>* oldsym;
1895   bool resolve_oldsym;
1896
1897   if (parameters->target().is_big_endian())
1898     {
1899 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1900       sym = this->define_special_symbol<size, true>(&name, &version,
1901                                                     only_if_ref, &oldsym,
1902                                                     &resolve_oldsym);
1903 #else
1904       gold_unreachable();
1905 #endif
1906     }
1907   else
1908     {
1909 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1910       sym = this->define_special_symbol<size, false>(&name, &version,
1911                                                      only_if_ref, &oldsym,
1912                                                      &resolve_oldsym);
1913 #else
1914       gold_unreachable();
1915 #endif
1916     }
1917
1918   if (sym == NULL)
1919     return NULL;
1920
1921   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1922                            visibility, nonvis, offset_base);
1923
1924   if (oldsym == NULL)
1925     {
1926       if (binding == elfcpp::STB_LOCAL
1927           || this->version_script_.symbol_is_local(name))
1928         this->force_local(sym);
1929       else if (version != NULL)
1930         sym->set_is_default();
1931       return sym;
1932     }
1933
1934   if (Symbol_table::should_override_with_special(oldsym, defined))
1935     this->override_with_special(oldsym, sym);
1936
1937   if (resolve_oldsym)
1938     return sym;
1939   else
1940     {
1941       delete sym;
1942       return oldsym;
1943     }
1944 }
1945
1946 // Define a special symbol with a constant value.  It is a multiple
1947 // definition error if this symbol is already defined.
1948
1949 Symbol*
1950 Symbol_table::define_as_constant(const char* name,
1951                                  const char* version,
1952                                  Defined defined,
1953                                  uint64_t value,
1954                                  uint64_t symsize,
1955                                  elfcpp::STT type,
1956                                  elfcpp::STB binding,
1957                                  elfcpp::STV visibility,
1958                                  unsigned char nonvis,
1959                                  bool only_if_ref,
1960                                  bool force_override)
1961 {
1962   if (parameters->target().get_size() == 32)
1963     {
1964 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1965       return this->do_define_as_constant<32>(name, version, defined, value,
1966                                              symsize, type, binding,
1967                                              visibility, nonvis, only_if_ref,
1968                                              force_override);
1969 #else
1970       gold_unreachable();
1971 #endif
1972     }
1973   else if (parameters->target().get_size() == 64)
1974     {
1975 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1976       return this->do_define_as_constant<64>(name, version, defined, value,
1977                                              symsize, type, binding,
1978                                              visibility, nonvis, only_if_ref,
1979                                              force_override);
1980 #else
1981       gold_unreachable();
1982 #endif
1983     }
1984   else
1985     gold_unreachable();
1986 }
1987
1988 // Define a symbol as a constant, sized version.
1989
1990 template<int size>
1991 Sized_symbol<size>*
1992 Symbol_table::do_define_as_constant(
1993     const char* name,
1994     const char* version,
1995     Defined defined,
1996     typename elfcpp::Elf_types<size>::Elf_Addr value,
1997     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1998     elfcpp::STT type,
1999     elfcpp::STB binding,
2000     elfcpp::STV visibility,
2001     unsigned char nonvis,
2002     bool only_if_ref,
2003     bool force_override)
2004 {
2005   Sized_symbol<size>* sym;
2006   Sized_symbol<size>* oldsym;
2007   bool resolve_oldsym;
2008
2009   if (parameters->target().is_big_endian())
2010     {
2011 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2012       sym = this->define_special_symbol<size, true>(&name, &version,
2013                                                     only_if_ref, &oldsym,
2014                                                     &resolve_oldsym);
2015 #else
2016       gold_unreachable();
2017 #endif
2018     }
2019   else
2020     {
2021 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2022       sym = this->define_special_symbol<size, false>(&name, &version,
2023                                                      only_if_ref, &oldsym,
2024                                                      &resolve_oldsym);
2025 #else
2026       gold_unreachable();
2027 #endif
2028     }
2029
2030   if (sym == NULL)
2031     return NULL;
2032
2033   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2034                      nonvis);
2035
2036   if (oldsym == NULL)
2037     {
2038       // Version symbols are absolute symbols with name == version.
2039       // We don't want to force them to be local.
2040       if ((version == NULL
2041            || name != version
2042            || value != 0)
2043           && (binding == elfcpp::STB_LOCAL
2044               || this->version_script_.symbol_is_local(name)))
2045         this->force_local(sym);
2046       else if (version != NULL
2047                && (name != version || value != 0))
2048         sym->set_is_default();
2049       return sym;
2050     }
2051
2052   if (force_override
2053       || Symbol_table::should_override_with_special(oldsym, defined))
2054     this->override_with_special(oldsym, sym);
2055
2056   if (resolve_oldsym)
2057     return sym;
2058   else
2059     {
2060       delete sym;
2061       return oldsym;
2062     }
2063 }
2064
2065 // Define a set of symbols in output sections.
2066
2067 void
2068 Symbol_table::define_symbols(const Layout* layout, int count,
2069                              const Define_symbol_in_section* p,
2070                              bool only_if_ref)
2071 {
2072   for (int i = 0; i < count; ++i, ++p)
2073     {
2074       Output_section* os = layout->find_output_section(p->output_section);
2075       if (os != NULL)
2076         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2077                                     p->size, p->type, p->binding,
2078                                     p->visibility, p->nonvis,
2079                                     p->offset_is_from_end,
2080                                     only_if_ref || p->only_if_ref);
2081       else
2082         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2083                                  p->type, p->binding, p->visibility, p->nonvis,
2084                                  only_if_ref || p->only_if_ref,
2085                                  false);
2086     }
2087 }
2088
2089 // Define a set of symbols in output segments.
2090
2091 void
2092 Symbol_table::define_symbols(const Layout* layout, int count,
2093                              const Define_symbol_in_segment* p,
2094                              bool only_if_ref)
2095 {
2096   for (int i = 0; i < count; ++i, ++p)
2097     {
2098       Output_segment* os = layout->find_output_segment(p->segment_type,
2099                                                        p->segment_flags_set,
2100                                                        p->segment_flags_clear);
2101       if (os != NULL)
2102         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2103                                        p->size, p->type, p->binding,
2104                                        p->visibility, p->nonvis,
2105                                        p->offset_base,
2106                                        only_if_ref || p->only_if_ref);
2107       else
2108         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2109                                  p->type, p->binding, p->visibility, p->nonvis,
2110                                  only_if_ref || p->only_if_ref,
2111                                  false);
2112     }
2113 }
2114
2115 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2116 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2117 // the offset within POSD.
2118
2119 template<int size>
2120 void
2121 Symbol_table::define_with_copy_reloc(
2122     Sized_symbol<size>* csym,
2123     Output_data* posd,
2124     typename elfcpp::Elf_types<size>::Elf_Addr value)
2125 {
2126   gold_assert(csym->is_from_dynobj());
2127   gold_assert(!csym->is_copied_from_dynobj());
2128   Object* object = csym->object();
2129   gold_assert(object->is_dynamic());
2130   Dynobj* dynobj = static_cast<Dynobj*>(object);
2131
2132   // Our copied variable has to override any variable in a shared
2133   // library.
2134   elfcpp::STB binding = csym->binding();
2135   if (binding == elfcpp::STB_WEAK)
2136     binding = elfcpp::STB_GLOBAL;
2137
2138   this->define_in_output_data(csym->name(), csym->version(), COPY,
2139                               posd, value, csym->symsize(),
2140                               csym->type(), binding,
2141                               csym->visibility(), csym->nonvis(),
2142                               false, false);
2143
2144   csym->set_is_copied_from_dynobj();
2145   csym->set_needs_dynsym_entry();
2146
2147   this->copied_symbol_dynobjs_[csym] = dynobj;
2148
2149   // We have now defined all aliases, but we have not entered them all
2150   // in the copied_symbol_dynobjs_ map.
2151   if (csym->has_alias())
2152     {
2153       Symbol* sym = csym;
2154       while (true)
2155         {
2156           sym = this->weak_aliases_[sym];
2157           if (sym == csym)
2158             break;
2159           gold_assert(sym->output_data() == posd);
2160
2161           sym->set_is_copied_from_dynobj();
2162           this->copied_symbol_dynobjs_[sym] = dynobj;
2163         }
2164     }
2165 }
2166
2167 // SYM is defined using a COPY reloc.  Return the dynamic object where
2168 // the original definition was found.
2169
2170 Dynobj*
2171 Symbol_table::get_copy_source(const Symbol* sym) const
2172 {
2173   gold_assert(sym->is_copied_from_dynobj());
2174   Copied_symbol_dynobjs::const_iterator p =
2175     this->copied_symbol_dynobjs_.find(sym);
2176   gold_assert(p != this->copied_symbol_dynobjs_.end());
2177   return p->second;
2178 }
2179
2180 // Add any undefined symbols named on the command line.
2181
2182 void
2183 Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
2184 {
2185   if (parameters->options().any_undefined()
2186       || layout->script_options()->any_unreferenced())
2187     {
2188       if (parameters->target().get_size() == 32)
2189         {
2190 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2191           this->do_add_undefined_symbols_from_command_line<32>(layout);
2192 #else
2193           gold_unreachable();
2194 #endif
2195         }
2196       else if (parameters->target().get_size() == 64)
2197         {
2198 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2199           this->do_add_undefined_symbols_from_command_line<64>(layout);
2200 #else
2201           gold_unreachable();
2202 #endif
2203         }
2204       else
2205         gold_unreachable();
2206     }
2207 }
2208
2209 template<int size>
2210 void
2211 Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
2212 {
2213   for (options::String_set::const_iterator p =
2214          parameters->options().undefined_begin();
2215        p != parameters->options().undefined_end();
2216        ++p)
2217     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2218
2219   for (Script_options::referenced_const_iterator p =
2220          layout->script_options()->referenced_begin();
2221        p != layout->script_options()->referenced_end();
2222        ++p)
2223     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2224 }
2225
2226 template<int size>
2227 void
2228 Symbol_table::add_undefined_symbol_from_command_line(const char* name)
2229 {
2230   if (this->lookup(name) != NULL)
2231     return;
2232
2233   const char* version = NULL;
2234
2235   Sized_symbol<size>* sym;
2236   Sized_symbol<size>* oldsym;
2237   bool resolve_oldsym;
2238   if (parameters->target().is_big_endian())
2239     {
2240 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2241       sym = this->define_special_symbol<size, true>(&name, &version,
2242                                                     false, &oldsym,
2243                                                     &resolve_oldsym);
2244 #else
2245       gold_unreachable();
2246 #endif
2247     }
2248   else
2249     {
2250 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2251       sym = this->define_special_symbol<size, false>(&name, &version,
2252                                                      false, &oldsym,
2253                                                      &resolve_oldsym);
2254 #else
2255       gold_unreachable();
2256 #endif
2257     }
2258
2259   gold_assert(oldsym == NULL);
2260
2261   sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2262                       elfcpp::STV_DEFAULT, 0);
2263   ++this->saw_undefined_;
2264 }
2265
2266 // Set the dynamic symbol indexes.  INDEX is the index of the first
2267 // global dynamic symbol.  Pointers to the symbols are stored into the
2268 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2269 // updated dynamic symbol index.
2270
2271 unsigned int
2272 Symbol_table::set_dynsym_indexes(unsigned int index,
2273                                  std::vector<Symbol*>* syms,
2274                                  Stringpool* dynpool,
2275                                  Versions* versions)
2276 {
2277   for (Symbol_table_type::iterator p = this->table_.begin();
2278        p != this->table_.end();
2279        ++p)
2280     {
2281       Symbol* sym = p->second;
2282
2283       // Note that SYM may already have a dynamic symbol index, since
2284       // some symbols appear more than once in the symbol table, with
2285       // and without a version.
2286
2287       if (!sym->should_add_dynsym_entry(this))
2288         sym->set_dynsym_index(-1U);
2289       else if (!sym->has_dynsym_index())
2290         {
2291           sym->set_dynsym_index(index);
2292           ++index;
2293           syms->push_back(sym);
2294           dynpool->add(sym->name(), false, NULL);
2295
2296           // Record any version information.
2297           if (sym->version() != NULL)
2298             versions->record_version(this, dynpool, sym);
2299
2300           // If the symbol is defined in a dynamic object and is
2301           // referenced in a regular object, then mark the dynamic
2302           // object as needed.  This is used to implement --as-needed.
2303           if (sym->is_from_dynobj() && sym->in_reg())
2304             sym->object()->set_is_needed();
2305         }
2306     }
2307
2308   // Finish up the versions.  In some cases this may add new dynamic
2309   // symbols.
2310   index = versions->finalize(this, index, syms);
2311
2312   return index;
2313 }
2314
2315 // Set the final values for all the symbols.  The index of the first
2316 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2317 // file offset OFF.  Add their names to POOL.  Return the new file
2318 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2319
2320 off_t
2321 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2322                        size_t dyncount, Stringpool* pool,
2323                        unsigned int* plocal_symcount)
2324 {
2325   off_t ret;
2326
2327   gold_assert(*plocal_symcount != 0);
2328   this->first_global_index_ = *plocal_symcount;
2329
2330   this->dynamic_offset_ = dynoff;
2331   this->first_dynamic_global_index_ = dyn_global_index;
2332   this->dynamic_count_ = dyncount;
2333
2334   if (parameters->target().get_size() == 32)
2335     {
2336 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2337       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2338 #else
2339       gold_unreachable();
2340 #endif
2341     }
2342   else if (parameters->target().get_size() == 64)
2343     {
2344 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2345       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2346 #else
2347       gold_unreachable();
2348 #endif
2349     }
2350   else
2351     gold_unreachable();
2352
2353   // Now that we have the final symbol table, we can reliably note
2354   // which symbols should get warnings.
2355   this->warnings_.note_warnings(this);
2356
2357   return ret;
2358 }
2359
2360 // SYM is going into the symbol table at *PINDEX.  Add the name to
2361 // POOL, update *PINDEX and *POFF.
2362
2363 template<int size>
2364 void
2365 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2366                                   unsigned int* pindex, off_t* poff)
2367 {
2368   sym->set_symtab_index(*pindex);
2369   pool->add(sym->name(), false, NULL);
2370   ++*pindex;
2371   *poff += elfcpp::Elf_sizes<size>::sym_size;
2372 }
2373
2374 // Set the final value for all the symbols.  This is called after
2375 // Layout::finalize, so all the output sections have their final
2376 // address.
2377
2378 template<int size>
2379 off_t
2380 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2381                              unsigned int* plocal_symcount)
2382 {
2383   off = align_address(off, size >> 3);
2384   this->offset_ = off;
2385
2386   unsigned int index = *plocal_symcount;
2387   const unsigned int orig_index = index;
2388
2389   // First do all the symbols which have been forced to be local, as
2390   // they must appear before all global symbols.
2391   for (Forced_locals::iterator p = this->forced_locals_.begin();
2392        p != this->forced_locals_.end();
2393        ++p)
2394     {
2395       Symbol* sym = *p;
2396       gold_assert(sym->is_forced_local());
2397       if (this->sized_finalize_symbol<size>(sym))
2398         {
2399           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2400           ++*plocal_symcount;
2401         }
2402     }
2403
2404   // Now do all the remaining symbols.
2405   for (Symbol_table_type::iterator p = this->table_.begin();
2406        p != this->table_.end();
2407        ++p)
2408     {
2409       Symbol* sym = p->second;
2410       if (this->sized_finalize_symbol<size>(sym))
2411         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2412     }
2413
2414   this->output_count_ = index - orig_index;
2415
2416   return off;
2417 }
2418
2419 // Compute the final value of SYM and store status in location PSTATUS.
2420 // During relaxation, this may be called multiple times for a symbol to
2421 // compute its would-be final value in each relaxation pass.
2422
2423 template<int size>
2424 typename Sized_symbol<size>::Value_type
2425 Symbol_table::compute_final_value(
2426     const Sized_symbol<size>* sym,
2427     Compute_final_value_status* pstatus) const
2428 {
2429   typedef typename Sized_symbol<size>::Value_type Value_type;
2430   Value_type value;
2431
2432   switch (sym->source())
2433     {
2434     case Symbol::FROM_OBJECT:
2435       {
2436         bool is_ordinary;
2437         unsigned int shndx = sym->shndx(&is_ordinary);
2438
2439         if (!is_ordinary
2440             && shndx != elfcpp::SHN_ABS
2441             && !Symbol::is_common_shndx(shndx))
2442           {
2443             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2444             return 0;
2445           }
2446
2447         Object* symobj = sym->object();
2448         if (symobj->is_dynamic())
2449           {
2450             value = 0;
2451             shndx = elfcpp::SHN_UNDEF;
2452           }
2453         else if (symobj->pluginobj() != NULL)
2454           {
2455             value = 0;
2456             shndx = elfcpp::SHN_UNDEF;
2457           }
2458         else if (shndx == elfcpp::SHN_UNDEF)
2459           value = 0;
2460         else if (!is_ordinary
2461                  && (shndx == elfcpp::SHN_ABS
2462                      || Symbol::is_common_shndx(shndx)))
2463           value = sym->value();
2464         else
2465           {
2466             Relobj* relobj = static_cast<Relobj*>(symobj);
2467             Output_section* os = relobj->output_section(shndx);
2468
2469             if (this->is_section_folded(relobj, shndx))
2470               {
2471                 gold_assert(os == NULL);
2472                 // Get the os of the section it is folded onto.
2473                 Section_id folded = this->icf_->get_folded_section(relobj,
2474                                                                    shndx);
2475                 gold_assert(folded.first != NULL);
2476                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2477                 unsigned folded_shndx = folded.second;
2478
2479                 os = folded_obj->output_section(folded_shndx);
2480                 gold_assert(os != NULL);
2481
2482                 // Replace (relobj, shndx) with canonical ICF input section.
2483                 shndx = folded_shndx;
2484                 relobj = folded_obj;
2485               }
2486
2487             uint64_t secoff64 = relobj->output_section_offset(shndx);
2488             if (os == NULL)
2489               {
2490                 bool static_or_reloc = (parameters->doing_static_link() ||
2491                                         parameters->options().relocatable());
2492                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2493
2494                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2495                 return 0;
2496               }
2497
2498             if (secoff64 == -1ULL)
2499               {
2500                 // The section needs special handling (e.g., a merge section).
2501
2502                 value = os->output_address(relobj, shndx, sym->value());
2503               }
2504             else
2505               {
2506                 Value_type secoff =
2507                   convert_types<Value_type, uint64_t>(secoff64);
2508                 if (sym->type() == elfcpp::STT_TLS)
2509                   value = sym->value() + os->tls_offset() + secoff;
2510                 else
2511                   value = sym->value() + os->address() + secoff;
2512               }
2513           }
2514       }
2515       break;
2516
2517     case Symbol::IN_OUTPUT_DATA:
2518       {
2519         Output_data* od = sym->output_data();
2520         value = sym->value();
2521         if (sym->type() != elfcpp::STT_TLS)
2522           value += od->address();
2523         else
2524           {
2525             Output_section* os = od->output_section();
2526             gold_assert(os != NULL);
2527             value += os->tls_offset() + (od->address() - os->address());
2528           }
2529         if (sym->offset_is_from_end())
2530           value += od->data_size();
2531       }
2532       break;
2533
2534     case Symbol::IN_OUTPUT_SEGMENT:
2535       {
2536         Output_segment* os = sym->output_segment();
2537         value = sym->value();
2538         if (sym->type() != elfcpp::STT_TLS)
2539           value += os->vaddr();
2540         switch (sym->offset_base())
2541           {
2542           case Symbol::SEGMENT_START:
2543             break;
2544           case Symbol::SEGMENT_END:
2545             value += os->memsz();
2546             break;
2547           case Symbol::SEGMENT_BSS:
2548             value += os->filesz();
2549             break;
2550           default:
2551             gold_unreachable();
2552           }
2553       }
2554       break;
2555
2556     case Symbol::IS_CONSTANT:
2557       value = sym->value();
2558       break;
2559
2560     case Symbol::IS_UNDEFINED:
2561       value = 0;
2562       break;
2563
2564     default:
2565       gold_unreachable();
2566     }
2567
2568   *pstatus = CFVS_OK;
2569   return value;
2570 }
2571
2572 // Finalize the symbol SYM.  This returns true if the symbol should be
2573 // added to the symbol table, false otherwise.
2574
2575 template<int size>
2576 bool
2577 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2578 {
2579   typedef typename Sized_symbol<size>::Value_type Value_type;
2580
2581   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2582
2583   // The default version of a symbol may appear twice in the symbol
2584   // table.  We only need to finalize it once.
2585   if (sym->has_symtab_index())
2586     return false;
2587
2588   if (!sym->in_reg())
2589     {
2590       gold_assert(!sym->has_symtab_index());
2591       sym->set_symtab_index(-1U);
2592       gold_assert(sym->dynsym_index() == -1U);
2593       return false;
2594     }
2595
2596   // Compute final symbol value.
2597   Compute_final_value_status status;
2598   Value_type value = this->compute_final_value(sym, &status);
2599
2600   switch (status)
2601     {
2602     case CFVS_OK:
2603       break;
2604     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2605       {
2606         bool is_ordinary;
2607         unsigned int shndx = sym->shndx(&is_ordinary);
2608         gold_error(_("%s: unsupported symbol section 0x%x"),
2609                    sym->demangled_name().c_str(), shndx);
2610       }
2611       break;
2612     case CFVS_NO_OUTPUT_SECTION:
2613       sym->set_symtab_index(-1U);
2614       return false;
2615     default:
2616       gold_unreachable();
2617     }
2618
2619   sym->set_value(value);
2620
2621   if (parameters->options().strip_all()
2622       || !parameters->options().should_retain_symbol(sym->name()))
2623     {
2624       sym->set_symtab_index(-1U);
2625       return false;
2626     }
2627
2628   return true;
2629 }
2630
2631 // Write out the global symbols.
2632
2633 void
2634 Symbol_table::write_globals(const Stringpool* sympool,
2635                             const Stringpool* dynpool,
2636                             Output_symtab_xindex* symtab_xindex,
2637                             Output_symtab_xindex* dynsym_xindex,
2638                             Output_file* of) const
2639 {
2640   switch (parameters->size_and_endianness())
2641     {
2642 #ifdef HAVE_TARGET_32_LITTLE
2643     case Parameters::TARGET_32_LITTLE:
2644       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2645                                            dynsym_xindex, of);
2646       break;
2647 #endif
2648 #ifdef HAVE_TARGET_32_BIG
2649     case Parameters::TARGET_32_BIG:
2650       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2651                                           dynsym_xindex, of);
2652       break;
2653 #endif
2654 #ifdef HAVE_TARGET_64_LITTLE
2655     case Parameters::TARGET_64_LITTLE:
2656       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2657                                            dynsym_xindex, of);
2658       break;
2659 #endif
2660 #ifdef HAVE_TARGET_64_BIG
2661     case Parameters::TARGET_64_BIG:
2662       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2663                                           dynsym_xindex, of);
2664       break;
2665 #endif
2666     default:
2667       gold_unreachable();
2668     }
2669 }
2670
2671 // Write out the global symbols.
2672
2673 template<int size, bool big_endian>
2674 void
2675 Symbol_table::sized_write_globals(const Stringpool* sympool,
2676                                   const Stringpool* dynpool,
2677                                   Output_symtab_xindex* symtab_xindex,
2678                                   Output_symtab_xindex* dynsym_xindex,
2679                                   Output_file* of) const
2680 {
2681   const Target& target = parameters->target();
2682
2683   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2684
2685   const unsigned int output_count = this->output_count_;
2686   const section_size_type oview_size = output_count * sym_size;
2687   const unsigned int first_global_index = this->first_global_index_;
2688   unsigned char* psyms;
2689   if (this->offset_ == 0 || output_count == 0)
2690     psyms = NULL;
2691   else
2692     psyms = of->get_output_view(this->offset_, oview_size);
2693
2694   const unsigned int dynamic_count = this->dynamic_count_;
2695   const section_size_type dynamic_size = dynamic_count * sym_size;
2696   const unsigned int first_dynamic_global_index =
2697     this->first_dynamic_global_index_;
2698   unsigned char* dynamic_view;
2699   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2700     dynamic_view = NULL;
2701   else
2702     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2703
2704   for (Symbol_table_type::const_iterator p = this->table_.begin();
2705        p != this->table_.end();
2706        ++p)
2707     {
2708       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2709
2710       // Possibly warn about unresolved symbols in shared libraries.
2711       this->warn_about_undefined_dynobj_symbol(sym);
2712
2713       unsigned int sym_index = sym->symtab_index();
2714       unsigned int dynsym_index;
2715       if (dynamic_view == NULL)
2716         dynsym_index = -1U;
2717       else
2718         dynsym_index = sym->dynsym_index();
2719
2720       if (sym_index == -1U && dynsym_index == -1U)
2721         {
2722           // This symbol is not included in the output file.
2723           continue;
2724         }
2725
2726       unsigned int shndx;
2727       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2728       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2729       elfcpp::STB binding = sym->binding();
2730       switch (sym->source())
2731         {
2732         case Symbol::FROM_OBJECT:
2733           {
2734             bool is_ordinary;
2735             unsigned int in_shndx = sym->shndx(&is_ordinary);
2736
2737             if (!is_ordinary
2738                 && in_shndx != elfcpp::SHN_ABS
2739                 && !Symbol::is_common_shndx(in_shndx))
2740               {
2741                 gold_error(_("%s: unsupported symbol section 0x%x"),
2742                            sym->demangled_name().c_str(), in_shndx);
2743                 shndx = in_shndx;
2744               }
2745             else
2746               {
2747                 Object* symobj = sym->object();
2748                 if (symobj->is_dynamic())
2749                   {
2750                     if (sym->needs_dynsym_value())
2751                       dynsym_value = target.dynsym_value(sym);
2752                     shndx = elfcpp::SHN_UNDEF;
2753                     if (sym->is_undef_binding_weak())
2754                       binding = elfcpp::STB_WEAK;
2755                     else
2756                       binding = elfcpp::STB_GLOBAL;
2757                   }
2758                 else if (symobj->pluginobj() != NULL)
2759                   shndx = elfcpp::SHN_UNDEF;
2760                 else if (in_shndx == elfcpp::SHN_UNDEF
2761                          || (!is_ordinary
2762                              && (in_shndx == elfcpp::SHN_ABS
2763                                  || Symbol::is_common_shndx(in_shndx))))
2764                   shndx = in_shndx;
2765                 else
2766                   {
2767                     Relobj* relobj = static_cast<Relobj*>(symobj);
2768                     Output_section* os = relobj->output_section(in_shndx);
2769                     if (this->is_section_folded(relobj, in_shndx))
2770                       {
2771                         // This global symbol must be written out even though
2772                         // it is folded.
2773                         // Get the os of the section it is folded onto.
2774                         Section_id folded =
2775                              this->icf_->get_folded_section(relobj, in_shndx);
2776                         gold_assert(folded.first !=NULL);
2777                         Relobj* folded_obj =
2778                           reinterpret_cast<Relobj*>(folded.first);
2779                         os = folded_obj->output_section(folded.second);
2780                         gold_assert(os != NULL);
2781                       }
2782                     gold_assert(os != NULL);
2783                     shndx = os->out_shndx();
2784
2785                     if (shndx >= elfcpp::SHN_LORESERVE)
2786                       {
2787                         if (sym_index != -1U)
2788                           symtab_xindex->add(sym_index, shndx);
2789                         if (dynsym_index != -1U)
2790                           dynsym_xindex->add(dynsym_index, shndx);
2791                         shndx = elfcpp::SHN_XINDEX;
2792                       }
2793
2794                     // In object files symbol values are section
2795                     // relative.
2796                     if (parameters->options().relocatable())
2797                       sym_value -= os->address();
2798                   }
2799               }
2800           }
2801           break;
2802
2803         case Symbol::IN_OUTPUT_DATA:
2804           shndx = sym->output_data()->out_shndx();
2805           if (shndx >= elfcpp::SHN_LORESERVE)
2806             {
2807               if (sym_index != -1U)
2808                 symtab_xindex->add(sym_index, shndx);
2809               if (dynsym_index != -1U)
2810                 dynsym_xindex->add(dynsym_index, shndx);
2811               shndx = elfcpp::SHN_XINDEX;
2812             }
2813           break;
2814
2815         case Symbol::IN_OUTPUT_SEGMENT:
2816           shndx = elfcpp::SHN_ABS;
2817           break;
2818
2819         case Symbol::IS_CONSTANT:
2820           shndx = elfcpp::SHN_ABS;
2821           break;
2822
2823         case Symbol::IS_UNDEFINED:
2824           shndx = elfcpp::SHN_UNDEF;
2825           break;
2826
2827         default:
2828           gold_unreachable();
2829         }
2830
2831       if (sym_index != -1U)
2832         {
2833           sym_index -= first_global_index;
2834           gold_assert(sym_index < output_count);
2835           unsigned char* ps = psyms + (sym_index * sym_size);
2836           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2837                                                      binding, sympool, ps);
2838         }
2839
2840       if (dynsym_index != -1U)
2841         {
2842           dynsym_index -= first_dynamic_global_index;
2843           gold_assert(dynsym_index < dynamic_count);
2844           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2845           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2846                                                      binding, dynpool, pd);
2847         }
2848     }
2849
2850   of->write_output_view(this->offset_, oview_size, psyms);
2851   if (dynamic_view != NULL)
2852     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2853 }
2854
2855 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2856 // strtab holding the name.
2857
2858 template<int size, bool big_endian>
2859 void
2860 Symbol_table::sized_write_symbol(
2861     Sized_symbol<size>* sym,
2862     typename elfcpp::Elf_types<size>::Elf_Addr value,
2863     unsigned int shndx,
2864     elfcpp::STB binding,
2865     const Stringpool* pool,
2866     unsigned char* p) const
2867 {
2868   elfcpp::Sym_write<size, big_endian> osym(p);
2869   osym.put_st_name(pool->get_offset(sym->name()));
2870   osym.put_st_value(value);
2871   // Use a symbol size of zero for undefined symbols from shared libraries.
2872   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2873     osym.put_st_size(0);
2874   else
2875     osym.put_st_size(sym->symsize());
2876   elfcpp::STT type = sym->type();
2877   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2878   if (type == elfcpp::STT_GNU_IFUNC
2879       && sym->is_from_dynobj())
2880     type = elfcpp::STT_FUNC;
2881   // A version script may have overridden the default binding.
2882   if (sym->is_forced_local())
2883     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2884   else
2885     osym.put_st_info(elfcpp::elf_st_info(binding, type));
2886   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2887   osym.put_st_shndx(shndx);
2888 }
2889
2890 // Check for unresolved symbols in shared libraries.  This is
2891 // controlled by the --allow-shlib-undefined option.
2892
2893 // We only warn about libraries for which we have seen all the
2894 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2895 // which were not seen in this link.  If we didn't see a DT_NEEDED
2896 // entry, we aren't going to be able to reliably report whether the
2897 // symbol is undefined.
2898
2899 // We also don't warn about libraries found in a system library
2900 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2901 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2902 // can have undefined references satisfied by ld-linux.so.
2903
2904 inline void
2905 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2906 {
2907   bool dummy;
2908   if (sym->source() == Symbol::FROM_OBJECT
2909       && sym->object()->is_dynamic()
2910       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2911       && sym->binding() != elfcpp::STB_WEAK
2912       && !parameters->options().allow_shlib_undefined()
2913       && !parameters->target().is_defined_by_abi(sym)
2914       && !sym->object()->is_in_system_directory())
2915     {
2916       // A very ugly cast.
2917       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2918       if (!dynobj->has_unknown_needed_entries())
2919         gold_undefined_symbol(sym);
2920     }
2921 }
2922
2923 // Write out a section symbol.  Return the update offset.
2924
2925 void
2926 Symbol_table::write_section_symbol(const Output_section* os,
2927                                    Output_symtab_xindex* symtab_xindex,
2928                                    Output_file* of,
2929                                    off_t offset) const
2930 {
2931   switch (parameters->size_and_endianness())
2932     {
2933 #ifdef HAVE_TARGET_32_LITTLE
2934     case Parameters::TARGET_32_LITTLE:
2935       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2936                                                   offset);
2937       break;
2938 #endif
2939 #ifdef HAVE_TARGET_32_BIG
2940     case Parameters::TARGET_32_BIG:
2941       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2942                                                  offset);
2943       break;
2944 #endif
2945 #ifdef HAVE_TARGET_64_LITTLE
2946     case Parameters::TARGET_64_LITTLE:
2947       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2948                                                   offset);
2949       break;
2950 #endif
2951 #ifdef HAVE_TARGET_64_BIG
2952     case Parameters::TARGET_64_BIG:
2953       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2954                                                  offset);
2955       break;
2956 #endif
2957     default:
2958       gold_unreachable();
2959     }
2960 }
2961
2962 // Write out a section symbol, specialized for size and endianness.
2963
2964 template<int size, bool big_endian>
2965 void
2966 Symbol_table::sized_write_section_symbol(const Output_section* os,
2967                                          Output_symtab_xindex* symtab_xindex,
2968                                          Output_file* of,
2969                                          off_t offset) const
2970 {
2971   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2972
2973   unsigned char* pov = of->get_output_view(offset, sym_size);
2974
2975   elfcpp::Sym_write<size, big_endian> osym(pov);
2976   osym.put_st_name(0);
2977   if (parameters->options().relocatable())
2978     osym.put_st_value(0);
2979   else
2980     osym.put_st_value(os->address());
2981   osym.put_st_size(0);
2982   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2983                                        elfcpp::STT_SECTION));
2984   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2985
2986   unsigned int shndx = os->out_shndx();
2987   if (shndx >= elfcpp::SHN_LORESERVE)
2988     {
2989       symtab_xindex->add(os->symtab_index(), shndx);
2990       shndx = elfcpp::SHN_XINDEX;
2991     }
2992   osym.put_st_shndx(shndx);
2993
2994   of->write_output_view(offset, sym_size, pov);
2995 }
2996
2997 // Print statistical information to stderr.  This is used for --stats.
2998
2999 void
3000 Symbol_table::print_stats() const
3001 {
3002 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
3003   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
3004           program_name, this->table_.size(), this->table_.bucket_count());
3005 #else
3006   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
3007           program_name, this->table_.size());
3008 #endif
3009   this->namepool_.print_stats("symbol table stringpool");
3010 }
3011
3012 // We check for ODR violations by looking for symbols with the same
3013 // name for which the debugging information reports that they were
3014 // defined in different source locations.  When comparing the source
3015 // location, we consider instances with the same base filename to be
3016 // the same.  This is because different object files/shared libraries
3017 // can include the same header file using different paths, and
3018 // different optimization settings can make the line number appear to
3019 // be a couple lines off, and we don't want to report an ODR violation
3020 // in those cases.
3021
3022 // This struct is used to compare line information, as returned by
3023 // Dwarf_line_info::one_addr2line.  It implements a < comparison
3024 // operator used with std::set.
3025
3026 struct Odr_violation_compare
3027 {
3028   bool
3029   operator()(const std::string& s1, const std::string& s2) const
3030   {
3031     // Inputs should be of the form "dirname/filename:linenum" where
3032     // "dirname/" is optional.  We want to compare just the filename.
3033
3034     // Find the last '/' and ':' in each string.
3035     std::string::size_type s1begin = s1.rfind('/');
3036     std::string::size_type s2begin = s2.rfind('/');
3037     std::string::size_type s1end = s1.rfind(':');
3038     std::string::size_type s2end = s2.rfind(':');
3039     // If there was no '/' in a string, start at the beginning.
3040     if (s1begin == std::string::npos)
3041       s1begin = 0;
3042     if (s2begin == std::string::npos)
3043       s2begin = 0;
3044     // If the ':' appeared in the directory name, compare to the end
3045     // of the string.
3046     if (s1end < s1begin)
3047       s1end = s1.size();
3048     if (s2end < s2begin)
3049       s2end = s2.size();
3050     // Compare takes lengths, not end indices.
3051     return s1.compare(s1begin, s1end - s1begin,
3052                       s2, s2begin, s2end - s2begin) < 0;
3053   }
3054 };
3055
3056 // Check candidate_odr_violations_ to find symbols with the same name
3057 // but apparently different definitions (different source-file/line-no).
3058
3059 void
3060 Symbol_table::detect_odr_violations(const Task* task,
3061                                     const char* output_file_name) const
3062 {
3063   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3064        it != candidate_odr_violations_.end();
3065        ++it)
3066     {
3067       const char* symbol_name = it->first;
3068       // Maps from symbol location to a sample object file we found
3069       // that location in.  We use a sorted map so the location order
3070       // is deterministic, but we only store an arbitrary object file
3071       // to avoid copying lots of names.
3072       std::map<std::string, std::string, Odr_violation_compare> line_nums;
3073
3074       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3075                locs = it->second.begin();
3076            locs != it->second.end();
3077            ++locs)
3078         {
3079           // We need to lock the object in order to read it.  This
3080           // means that we have to run in a singleton Task.  If we
3081           // want to run this in a general Task for better
3082           // performance, we will need one Task for object, plus
3083           // appropriate locking to ensure that we don't conflict with
3084           // other uses of the object.  Also note, one_addr2line is not
3085           // currently thread-safe.
3086           Task_lock_obj<Object> tl(task, locs->object);
3087           // 16 is the size of the object-cache that one_addr2line should use.
3088           std::string lineno = Dwarf_line_info::one_addr2line(
3089               locs->object, locs->shndx, locs->offset, 16);
3090           if (!lineno.empty())
3091             {
3092               std::string& sample_object = line_nums[lineno];
3093               if (sample_object.empty())
3094                 sample_object = locs->object->name();
3095             }
3096         }
3097
3098       if (line_nums.size() > 1)
3099         {
3100           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3101                          "places (possible ODR violation):"),
3102                        output_file_name, demangle(symbol_name).c_str());
3103           for (std::map<std::string, std::string>::const_iterator it2 =
3104                  line_nums.begin();
3105                it2 != line_nums.end();
3106                ++it2)
3107             fprintf(stderr, _("  %s from %s\n"),
3108                     it2->first.c_str(), it2->second.c_str());
3109         }
3110     }
3111   // We only call one_addr2line() in this function, so we can clear its cache.
3112   Dwarf_line_info::clear_addr2line_cache();
3113 }
3114
3115 // Warnings functions.
3116
3117 // Add a new warning.
3118
3119 void
3120 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3121                       const std::string& warning)
3122 {
3123   name = symtab->canonicalize_name(name);
3124   this->warnings_[name].set(obj, warning);
3125 }
3126
3127 // Look through the warnings and mark the symbols for which we should
3128 // warn.  This is called during Layout::finalize when we know the
3129 // sources for all the symbols.
3130
3131 void
3132 Warnings::note_warnings(Symbol_table* symtab)
3133 {
3134   for (Warning_table::iterator p = this->warnings_.begin();
3135        p != this->warnings_.end();
3136        ++p)
3137     {
3138       Symbol* sym = symtab->lookup(p->first, NULL);
3139       if (sym != NULL
3140           && sym->source() == Symbol::FROM_OBJECT
3141           && sym->object() == p->second.object)
3142         sym->set_has_warning();
3143     }
3144 }
3145
3146 // Issue a warning.  This is called when we see a relocation against a
3147 // symbol for which has a warning.
3148
3149 template<int size, bool big_endian>
3150 void
3151 Warnings::issue_warning(const Symbol* sym,
3152                         const Relocate_info<size, big_endian>* relinfo,
3153                         size_t relnum, off_t reloffset) const
3154 {
3155   gold_assert(sym->has_warning());
3156   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3157   gold_assert(p != this->warnings_.end());
3158   gold_warning_at_location(relinfo, relnum, reloffset,
3159                            "%s", p->second.text.c_str());
3160 }
3161
3162 // Instantiate the templates we need.  We could use the configure
3163 // script to restrict this to only the ones needed for implemented
3164 // targets.
3165
3166 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3167 template
3168 void
3169 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3170 #endif
3171
3172 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3173 template
3174 void
3175 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3176 #endif
3177
3178 #ifdef HAVE_TARGET_32_LITTLE
3179 template
3180 void
3181 Symbol_table::add_from_relobj<32, false>(
3182     Sized_relobj<32, false>* relobj,
3183     const unsigned char* syms,
3184     size_t count,
3185     size_t symndx_offset,
3186     const char* sym_names,
3187     size_t sym_name_size,
3188     Sized_relobj<32, false>::Symbols* sympointers,
3189     size_t* defined);
3190 #endif
3191
3192 #ifdef HAVE_TARGET_32_BIG
3193 template
3194 void
3195 Symbol_table::add_from_relobj<32, true>(
3196     Sized_relobj<32, true>* relobj,
3197     const unsigned char* syms,
3198     size_t count,
3199     size_t symndx_offset,
3200     const char* sym_names,
3201     size_t sym_name_size,
3202     Sized_relobj<32, true>::Symbols* sympointers,
3203     size_t* defined);
3204 #endif
3205
3206 #ifdef HAVE_TARGET_64_LITTLE
3207 template
3208 void
3209 Symbol_table::add_from_relobj<64, false>(
3210     Sized_relobj<64, false>* relobj,
3211     const unsigned char* syms,
3212     size_t count,
3213     size_t symndx_offset,
3214     const char* sym_names,
3215     size_t sym_name_size,
3216     Sized_relobj<64, false>::Symbols* sympointers,
3217     size_t* defined);
3218 #endif
3219
3220 #ifdef HAVE_TARGET_64_BIG
3221 template
3222 void
3223 Symbol_table::add_from_relobj<64, true>(
3224     Sized_relobj<64, true>* relobj,
3225     const unsigned char* syms,
3226     size_t count,
3227     size_t symndx_offset,
3228     const char* sym_names,
3229     size_t sym_name_size,
3230     Sized_relobj<64, true>::Symbols* sympointers,
3231     size_t* defined);
3232 #endif
3233
3234 #ifdef HAVE_TARGET_32_LITTLE
3235 template
3236 Symbol*
3237 Symbol_table::add_from_pluginobj<32, false>(
3238     Sized_pluginobj<32, false>* obj,
3239     const char* name,
3240     const char* ver,
3241     elfcpp::Sym<32, false>* sym);
3242 #endif
3243
3244 #ifdef HAVE_TARGET_32_BIG
3245 template
3246 Symbol*
3247 Symbol_table::add_from_pluginobj<32, true>(
3248     Sized_pluginobj<32, true>* obj,
3249     const char* name,
3250     const char* ver,
3251     elfcpp::Sym<32, true>* sym);
3252 #endif
3253
3254 #ifdef HAVE_TARGET_64_LITTLE
3255 template
3256 Symbol*
3257 Symbol_table::add_from_pluginobj<64, false>(
3258     Sized_pluginobj<64, false>* obj,
3259     const char* name,
3260     const char* ver,
3261     elfcpp::Sym<64, false>* sym);
3262 #endif
3263
3264 #ifdef HAVE_TARGET_64_BIG
3265 template
3266 Symbol*
3267 Symbol_table::add_from_pluginobj<64, true>(
3268     Sized_pluginobj<64, true>* obj,
3269     const char* name,
3270     const char* ver,
3271     elfcpp::Sym<64, true>* sym);
3272 #endif
3273
3274 #ifdef HAVE_TARGET_32_LITTLE
3275 template
3276 void
3277 Symbol_table::add_from_dynobj<32, false>(
3278     Sized_dynobj<32, false>* dynobj,
3279     const unsigned char* syms,
3280     size_t count,
3281     const char* sym_names,
3282     size_t sym_name_size,
3283     const unsigned char* versym,
3284     size_t versym_size,
3285     const std::vector<const char*>* version_map,
3286     Sized_relobj<32, false>::Symbols* sympointers,
3287     size_t* defined);
3288 #endif
3289
3290 #ifdef HAVE_TARGET_32_BIG
3291 template
3292 void
3293 Symbol_table::add_from_dynobj<32, true>(
3294     Sized_dynobj<32, true>* dynobj,
3295     const unsigned char* syms,
3296     size_t count,
3297     const char* sym_names,
3298     size_t sym_name_size,
3299     const unsigned char* versym,
3300     size_t versym_size,
3301     const std::vector<const char*>* version_map,
3302     Sized_relobj<32, true>::Symbols* sympointers,
3303     size_t* defined);
3304 #endif
3305
3306 #ifdef HAVE_TARGET_64_LITTLE
3307 template
3308 void
3309 Symbol_table::add_from_dynobj<64, false>(
3310     Sized_dynobj<64, false>* dynobj,
3311     const unsigned char* syms,
3312     size_t count,
3313     const char* sym_names,
3314     size_t sym_name_size,
3315     const unsigned char* versym,
3316     size_t versym_size,
3317     const std::vector<const char*>* version_map,
3318     Sized_relobj<64, false>::Symbols* sympointers,
3319     size_t* defined);
3320 #endif
3321
3322 #ifdef HAVE_TARGET_64_BIG
3323 template
3324 void
3325 Symbol_table::add_from_dynobj<64, true>(
3326     Sized_dynobj<64, true>* dynobj,
3327     const unsigned char* syms,
3328     size_t count,
3329     const char* sym_names,
3330     size_t sym_name_size,
3331     const unsigned char* versym,
3332     size_t versym_size,
3333     const std::vector<const char*>* version_map,
3334     Sized_relobj<64, true>::Symbols* sympointers,
3335     size_t* defined);
3336 #endif
3337
3338 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3339 template
3340 void
3341 Symbol_table::define_with_copy_reloc<32>(
3342     Sized_symbol<32>* sym,
3343     Output_data* posd,
3344     elfcpp::Elf_types<32>::Elf_Addr value);
3345 #endif
3346
3347 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3348 template
3349 void
3350 Symbol_table::define_with_copy_reloc<64>(
3351     Sized_symbol<64>* sym,
3352     Output_data* posd,
3353     elfcpp::Elf_types<64>::Elf_Addr value);
3354 #endif
3355
3356 #ifdef HAVE_TARGET_32_LITTLE
3357 template
3358 void
3359 Warnings::issue_warning<32, false>(const Symbol* sym,
3360                                    const Relocate_info<32, false>* relinfo,
3361                                    size_t relnum, off_t reloffset) const;
3362 #endif
3363
3364 #ifdef HAVE_TARGET_32_BIG
3365 template
3366 void
3367 Warnings::issue_warning<32, true>(const Symbol* sym,
3368                                   const Relocate_info<32, true>* relinfo,
3369                                   size_t relnum, off_t reloffset) const;
3370 #endif
3371
3372 #ifdef HAVE_TARGET_64_LITTLE
3373 template
3374 void
3375 Warnings::issue_warning<64, false>(const Symbol* sym,
3376                                    const Relocate_info<64, false>* relinfo,
3377                                    size_t relnum, off_t reloffset) const;
3378 #endif
3379
3380 #ifdef HAVE_TARGET_64_BIG
3381 template
3382 void
3383 Warnings::issue_warning<64, true>(const Symbol* sym,
3384                                   const Relocate_info<64, true>* relinfo,
3385                                   size_t relnum, off_t reloffset) const;
3386 #endif
3387
3388 } // End namespace gold.