PR 11855
[external/binutils.git] / gold / symtab.cc
1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009, 2010 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 hash function.  The key values are Stringpool keys.
505
506 inline size_t
507 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
508 {
509   return key.first ^ key.second;
510 }
511
512 // The symbol table key equality function.  This is called with
513 // Stringpool keys.
514
515 inline bool
516 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
517                                           const Symbol_table_key& k2) const
518 {
519   return k1.first == k2.first && k1.second == k2.second;
520 }
521
522 bool
523 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
524 {
525   return (parameters->options().icf_enabled()
526           && this->icf_->is_section_folded(obj, shndx));
527 }
528
529 // For symbols that have been listed with -u option, add them to the
530 // work list to avoid gc'ing them.
531
532 void 
533 Symbol_table::gc_mark_undef_symbols(Layout* layout)
534 {
535   for (options::String_set::const_iterator p =
536          parameters->options().undefined_begin();
537        p != parameters->options().undefined_end();
538        ++p)
539     {
540       const char* name = p->c_str();
541       Symbol* sym = this->lookup(name);
542       gold_assert (sym != NULL);
543       if (sym->source() == Symbol::FROM_OBJECT 
544           && !sym->object()->is_dynamic())
545         {
546           Relobj* obj = static_cast<Relobj*>(sym->object());
547           bool is_ordinary;
548           unsigned int shndx = sym->shndx(&is_ordinary);
549           if (is_ordinary)
550             {
551               gold_assert(this->gc_ != NULL);
552               this->gc_->worklist().push(Section_id(obj, shndx));
553             }
554         }
555     }
556
557   for (Script_options::referenced_const_iterator p =
558          layout->script_options()->referenced_begin();
559        p != layout->script_options()->referenced_end();
560        ++p)
561     {
562       Symbol* sym = this->lookup(p->c_str());
563       gold_assert(sym != NULL);
564       if (sym->source() == Symbol::FROM_OBJECT
565           && !sym->object()->is_dynamic())
566         {
567           Relobj* obj = static_cast<Relobj*>(sym->object());
568           bool is_ordinary;
569           unsigned int shndx = sym->shndx(&is_ordinary);
570           if (is_ordinary)
571             {
572               gold_assert(this->gc_ != NULL);
573               this->gc_->worklist().push(Section_id(obj, shndx));
574             }
575         }
576     }
577 }
578
579 void
580 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
581 {
582   if (!sym->is_from_dynobj() 
583       && sym->is_externally_visible())
584     {
585       //Add the object and section to the work list.
586       Relobj* obj = static_cast<Relobj*>(sym->object());
587       bool is_ordinary;
588       unsigned int shndx = sym->shndx(&is_ordinary);
589       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
590         {
591           gold_assert(this->gc_!= NULL);
592           this->gc_->worklist().push(Section_id(obj, shndx));
593         }
594     }
595 }
596
597 // When doing garbage collection, keep symbols that have been seen in
598 // dynamic objects.
599 inline void 
600 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
601 {
602   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
603       && !sym->object()->is_dynamic())
604     {
605       Relobj *obj = static_cast<Relobj*>(sym->object()); 
606       bool is_ordinary;
607       unsigned int shndx = sym->shndx(&is_ordinary);
608       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
609         {
610           gold_assert(this->gc_ != NULL);
611           this->gc_->worklist().push(Section_id(obj, shndx));
612         }
613     }
614 }
615
616 // Make TO a symbol which forwards to FROM.
617
618 void
619 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
620 {
621   gold_assert(from != to);
622   gold_assert(!from->is_forwarder() && !to->is_forwarder());
623   this->forwarders_[from] = to;
624   from->set_forwarder();
625 }
626
627 // Resolve the forwards from FROM, returning the real symbol.
628
629 Symbol*
630 Symbol_table::resolve_forwards(const Symbol* from) const
631 {
632   gold_assert(from->is_forwarder());
633   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
634     this->forwarders_.find(from);
635   gold_assert(p != this->forwarders_.end());
636   return p->second;
637 }
638
639 // Look up a symbol by name.
640
641 Symbol*
642 Symbol_table::lookup(const char* name, const char* version) const
643 {
644   Stringpool::Key name_key;
645   name = this->namepool_.find(name, &name_key);
646   if (name == NULL)
647     return NULL;
648
649   Stringpool::Key version_key = 0;
650   if (version != NULL)
651     {
652       version = this->namepool_.find(version, &version_key);
653       if (version == NULL)
654         return NULL;
655     }
656
657   Symbol_table_key key(name_key, version_key);
658   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
659   if (p == this->table_.end())
660     return NULL;
661   return p->second;
662 }
663
664 // Resolve a Symbol with another Symbol.  This is only used in the
665 // unusual case where there are references to both an unversioned
666 // symbol and a symbol with a version, and we then discover that that
667 // version is the default version.  Because this is unusual, we do
668 // this the slow way, by converting back to an ELF symbol.
669
670 template<int size, bool big_endian>
671 void
672 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
673 {
674   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
675   elfcpp::Sym_write<size, big_endian> esym(buf);
676   // We don't bother to set the st_name or the st_shndx field.
677   esym.put_st_value(from->value());
678   esym.put_st_size(from->symsize());
679   esym.put_st_info(from->binding(), from->type());
680   esym.put_st_other(from->visibility(), from->nonvis());
681   bool is_ordinary;
682   unsigned int shndx = from->shndx(&is_ordinary);
683   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
684                 from->version());
685   if (from->in_reg())
686     to->set_in_reg();
687   if (from->in_dyn())
688     to->set_in_dyn();
689   if (parameters->options().gc_sections())
690     this->gc_mark_dyn_syms(to);
691 }
692
693 // Record that a symbol is forced to be local by a version script or
694 // by visibility.
695
696 void
697 Symbol_table::force_local(Symbol* sym)
698 {
699   if (!sym->is_defined() && !sym->is_common())
700     return;
701   if (sym->is_forced_local())
702     {
703       // We already got this one.
704       return;
705     }
706   sym->set_is_forced_local();
707   this->forced_locals_.push_back(sym);
708 }
709
710 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
711 // is only called for undefined symbols, when at least one --wrap
712 // option was used.
713
714 const char*
715 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
716 {
717   // For some targets, we need to ignore a specific character when
718   // wrapping, and add it back later.
719   char prefix = '\0';
720   if (name[0] == parameters->target().wrap_char())
721     {
722       prefix = name[0];
723       ++name;
724     }
725
726   if (parameters->options().is_wrap(name))
727     {
728       // Turn NAME into __wrap_NAME.
729       std::string s;
730       if (prefix != '\0')
731         s += prefix;
732       s += "__wrap_";
733       s += name;
734
735       // This will give us both the old and new name in NAMEPOOL_, but
736       // that is OK.  Only the versions we need will wind up in the
737       // real string table in the output file.
738       return this->namepool_.add(s.c_str(), true, name_key);
739     }
740
741   const char* const real_prefix = "__real_";
742   const size_t real_prefix_length = strlen(real_prefix);
743   if (strncmp(name, real_prefix, real_prefix_length) == 0
744       && parameters->options().is_wrap(name + real_prefix_length))
745     {
746       // Turn __real_NAME into NAME.
747       std::string s;
748       if (prefix != '\0')
749         s += prefix;
750       s += name + real_prefix_length;
751       return this->namepool_.add(s.c_str(), true, name_key);
752     }
753
754   return name;
755 }
756
757 // This is called when we see a symbol NAME/VERSION, and the symbol
758 // already exists in the symbol table, and VERSION is marked as being
759 // the default version.  SYM is the NAME/VERSION symbol we just added.
760 // DEFAULT_IS_NEW is true if this is the first time we have seen the
761 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
762
763 template<int size, bool big_endian>
764 void
765 Symbol_table::define_default_version(Sized_symbol<size>* sym,
766                                      bool default_is_new,
767                                      Symbol_table_type::iterator pdef)
768 {
769   if (default_is_new)
770     {
771       // This is the first time we have seen NAME/NULL.  Make
772       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
773       // version.
774       pdef->second = sym;
775       sym->set_is_default();
776     }
777   else if (pdef->second == sym)
778     {
779       // NAME/NULL already points to NAME/VERSION.  Don't mark the
780       // symbol as the default if it is not already the default.
781     }
782   else
783     {
784       // This is the unfortunate case where we already have entries
785       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
786       // NAME/VERSION where VERSION is the default version.  We have
787       // already resolved this new symbol with the existing
788       // NAME/VERSION symbol.
789
790       // It's possible that NAME/NULL and NAME/VERSION are both
791       // defined in regular objects.  This can only happen if one
792       // object file defines foo and another defines foo@@ver.  This
793       // is somewhat obscure, but we call it a multiple definition
794       // error.
795
796       // It's possible that NAME/NULL actually has a version, in which
797       // case it won't be the same as VERSION.  This happens with
798       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
799       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
800       // then see an unadorned t2_2 in an object file and give it
801       // version VER1 from the version script.  This looks like a
802       // default definition for VER1, so it looks like we should merge
803       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
804       // not obvious that this is an error, either.  So we just punt.
805
806       // If one of the symbols has non-default visibility, and the
807       // other is defined in a shared object, then they are different
808       // symbols.
809
810       // Otherwise, we just resolve the symbols as though they were
811       // the same.
812
813       if (pdef->second->version() != NULL)
814         gold_assert(pdef->second->version() != sym->version());
815       else if (sym->visibility() != elfcpp::STV_DEFAULT
816                && pdef->second->is_from_dynobj())
817         ;
818       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
819                && sym->is_from_dynobj())
820         ;
821       else
822         {
823           const Sized_symbol<size>* symdef;
824           symdef = this->get_sized_symbol<size>(pdef->second);
825           Symbol_table::resolve<size, big_endian>(sym, symdef);
826           this->make_forwarder(pdef->second, sym);
827           pdef->second = sym;
828           sym->set_is_default();
829         }
830     }
831 }
832
833 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
834 // name and VERSION is the version; both are canonicalized.  DEF is
835 // whether this is the default version.  ST_SHNDX is the symbol's
836 // section index; IS_ORDINARY is whether this is a normal section
837 // rather than a special code.
838
839 // If IS_DEFAULT_VERSION is true, then this is the definition of a
840 // default version of a symbol.  That means that any lookup of
841 // NAME/NULL and any lookup of NAME/VERSION should always return the
842 // same symbol.  This is obvious for references, but in particular we
843 // want to do this for definitions: overriding NAME/NULL should also
844 // override NAME/VERSION.  If we don't do that, it would be very hard
845 // to override functions in a shared library which uses versioning.
846
847 // We implement this by simply making both entries in the hash table
848 // point to the same Symbol structure.  That is easy enough if this is
849 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
850 // that we have seen both already, in which case they will both have
851 // independent entries in the symbol table.  We can't simply change
852 // the symbol table entry, because we have pointers to the entries
853 // attached to the object files.  So we mark the entry attached to the
854 // object file as a forwarder, and record it in the forwarders_ map.
855 // Note that entries in the hash table will never be marked as
856 // forwarders.
857 //
858 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
859 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
860 // for a special section code.  ST_SHNDX may be modified if the symbol
861 // is defined in a section being discarded.
862
863 template<int size, bool big_endian>
864 Sized_symbol<size>*
865 Symbol_table::add_from_object(Object* object,
866                               const char *name,
867                               Stringpool::Key name_key,
868                               const char *version,
869                               Stringpool::Key version_key,
870                               bool is_default_version,
871                               const elfcpp::Sym<size, big_endian>& sym,
872                               unsigned int st_shndx,
873                               bool is_ordinary,
874                               unsigned int orig_st_shndx)
875 {
876   // Print a message if this symbol is being traced.
877   if (parameters->options().is_trace_symbol(name))
878     {
879       if (orig_st_shndx == elfcpp::SHN_UNDEF)
880         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
881       else
882         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
883     }
884
885   // For an undefined symbol, we may need to adjust the name using
886   // --wrap.
887   if (orig_st_shndx == elfcpp::SHN_UNDEF
888       && parameters->options().any_wrap())
889     {
890       const char* wrap_name = this->wrap_symbol(name, &name_key);
891       if (wrap_name != name)
892         {
893           // If we see a reference to malloc with version GLIBC_2.0,
894           // and we turn it into a reference to __wrap_malloc, then we
895           // discard the version number.  Otherwise the user would be
896           // required to specify the correct version for
897           // __wrap_malloc.
898           version = NULL;
899           version_key = 0;
900           name = wrap_name;
901         }
902     }
903
904   Symbol* const snull = NULL;
905   std::pair<typename Symbol_table_type::iterator, bool> ins =
906     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
907                                        snull));
908
909   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
910     std::make_pair(this->table_.end(), false);
911   if (is_default_version)
912     {
913       const Stringpool::Key vnull_key = 0;
914       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
915                                                                      vnull_key),
916                                                       snull));
917     }
918
919   // ins.first: an iterator, which is a pointer to a pair.
920   // ins.first->first: the key (a pair of name and version).
921   // ins.first->second: the value (Symbol*).
922   // ins.second: true if new entry was inserted, false if not.
923
924   Sized_symbol<size>* ret;
925   bool was_undefined;
926   bool was_common;
927   if (!ins.second)
928     {
929       // We already have an entry for NAME/VERSION.
930       ret = this->get_sized_symbol<size>(ins.first->second);
931       gold_assert(ret != NULL);
932
933       was_undefined = ret->is_undefined();
934       was_common = ret->is_common();
935
936       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
937                     version);
938       if (parameters->options().gc_sections())
939         this->gc_mark_dyn_syms(ret);
940
941       if (is_default_version)
942         this->define_default_version<size, big_endian>(ret, insdefault.second,
943                                                        insdefault.first);
944     }
945   else
946     {
947       // This is the first time we have seen NAME/VERSION.
948       gold_assert(ins.first->second == NULL);
949
950       if (is_default_version && !insdefault.second)
951         {
952           // We already have an entry for NAME/NULL.  If we override
953           // it, then change it to NAME/VERSION.
954           ret = this->get_sized_symbol<size>(insdefault.first->second);
955
956           was_undefined = ret->is_undefined();
957           was_common = ret->is_common();
958
959           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
960                         version);
961           if (parameters->options().gc_sections())
962             this->gc_mark_dyn_syms(ret);
963           ins.first->second = ret;
964         }
965       else
966         {
967           was_undefined = false;
968           was_common = false;
969
970           Sized_target<size, big_endian>* target =
971             parameters->sized_target<size, big_endian>();
972           if (!target->has_make_symbol())
973             ret = new Sized_symbol<size>();
974           else
975             {
976               ret = target->make_symbol();
977               if (ret == NULL)
978                 {
979                   // This means that we don't want a symbol table
980                   // entry after all.
981                   if (!is_default_version)
982                     this->table_.erase(ins.first);
983                   else
984                     {
985                       this->table_.erase(insdefault.first);
986                       // Inserting INSDEFAULT invalidated INS.
987                       this->table_.erase(std::make_pair(name_key,
988                                                         version_key));
989                     }
990                   return NULL;
991                 }
992             }
993
994           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
995
996           ins.first->second = ret;
997           if (is_default_version)
998             {
999               // This is the first time we have seen NAME/NULL.  Point
1000               // it at the new entry for NAME/VERSION.
1001               gold_assert(insdefault.second);
1002               insdefault.first->second = ret;
1003             }
1004         }
1005
1006       if (is_default_version)
1007         ret->set_is_default();
1008     }
1009
1010   // Record every time we see a new undefined symbol, to speed up
1011   // archive groups.
1012   if (!was_undefined && ret->is_undefined())
1013     ++this->saw_undefined_;
1014
1015   // Keep track of common symbols, to speed up common symbol
1016   // allocation.
1017   if (!was_common && ret->is_common())
1018     {
1019       if (ret->type() == elfcpp::STT_TLS)
1020         this->tls_commons_.push_back(ret);
1021       else if (!is_ordinary
1022                && st_shndx == parameters->target().small_common_shndx())
1023         this->small_commons_.push_back(ret);
1024       else if (!is_ordinary
1025                && st_shndx == parameters->target().large_common_shndx())
1026         this->large_commons_.push_back(ret);
1027       else
1028         this->commons_.push_back(ret);
1029     }
1030
1031   // If we're not doing a relocatable link, then any symbol with
1032   // hidden or internal visibility is local.
1033   if ((ret->visibility() == elfcpp::STV_HIDDEN
1034        || ret->visibility() == elfcpp::STV_INTERNAL)
1035       && (ret->binding() == elfcpp::STB_GLOBAL
1036           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1037           || ret->binding() == elfcpp::STB_WEAK)
1038       && !parameters->options().relocatable())
1039     this->force_local(ret);
1040
1041   return ret;
1042 }
1043
1044 // Add all the symbols in a relocatable object to the hash table.
1045
1046 template<int size, bool big_endian>
1047 void
1048 Symbol_table::add_from_relobj(
1049     Sized_relobj<size, big_endian>* relobj,
1050     const unsigned char* syms,
1051     size_t count,
1052     size_t symndx_offset,
1053     const char* sym_names,
1054     size_t sym_name_size,
1055     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1056     size_t *defined)
1057 {
1058   *defined = 0;
1059
1060   gold_assert(size == parameters->target().get_size());
1061
1062   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1063
1064   const bool just_symbols = relobj->just_symbols();
1065
1066   const unsigned char* p = syms;
1067   for (size_t i = 0; i < count; ++i, p += sym_size)
1068     {
1069       (*sympointers)[i] = NULL;
1070
1071       elfcpp::Sym<size, big_endian> sym(p);
1072
1073       unsigned int st_name = sym.get_st_name();
1074       if (st_name >= sym_name_size)
1075         {
1076           relobj->error(_("bad global symbol name offset %u at %zu"),
1077                         st_name, i);
1078           continue;
1079         }
1080
1081       const char* name = sym_names + st_name;
1082
1083       bool is_ordinary;
1084       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1085                                                        sym.get_st_shndx(),
1086                                                        &is_ordinary);
1087       unsigned int orig_st_shndx = st_shndx;
1088       if (!is_ordinary)
1089         orig_st_shndx = elfcpp::SHN_UNDEF;
1090
1091       if (st_shndx != elfcpp::SHN_UNDEF)
1092         ++*defined;
1093
1094       // A symbol defined in a section which we are not including must
1095       // be treated as an undefined symbol.
1096       bool is_defined_in_discarded_section = false;
1097       if (st_shndx != elfcpp::SHN_UNDEF
1098           && is_ordinary
1099           && !relobj->is_section_included(st_shndx)
1100           && !this->is_section_folded(relobj, st_shndx))
1101         {
1102           st_shndx = elfcpp::SHN_UNDEF;
1103           is_defined_in_discarded_section = true;
1104         }
1105
1106       // In an object file, an '@' in the name separates the symbol
1107       // name from the version name.  If there are two '@' characters,
1108       // this is the default version.
1109       const char* ver = strchr(name, '@');
1110       Stringpool::Key ver_key = 0;
1111       int namelen = 0;
1112       // IS_DEFAULT_VERSION: is the version default?
1113       // IS_FORCED_LOCAL: is the symbol forced local?
1114       bool is_default_version = false;
1115       bool is_forced_local = false;
1116
1117       if (ver != NULL)
1118         {
1119           // The symbol name is of the form foo@VERSION or foo@@VERSION
1120           namelen = ver - name;
1121           ++ver;
1122           if (*ver == '@')
1123             {
1124               is_default_version = true;
1125               ++ver;
1126             }
1127           ver = this->namepool_.add(ver, true, &ver_key);
1128         }
1129       // We don't want to assign a version to an undefined symbol,
1130       // even if it is listed in the version script.  FIXME: What
1131       // about a common symbol?
1132       else
1133         {
1134           namelen = strlen(name);
1135           if (!this->version_script_.empty()
1136               && st_shndx != elfcpp::SHN_UNDEF)
1137             {
1138               // The symbol name did not have a version, but the
1139               // version script may assign a version anyway.
1140               std::string version;
1141               bool is_global;
1142               if (this->version_script_.get_symbol_version(name, &version,
1143                                                            &is_global))
1144                 {
1145                   if (!is_global)
1146                     is_forced_local = true;
1147                   else if (!version.empty())
1148                     {
1149                       ver = this->namepool_.add_with_length(version.c_str(),
1150                                                             version.length(),
1151                                                             true,
1152                                                             &ver_key);
1153                       is_default_version = true;
1154                     }
1155                 }
1156             }
1157         }
1158
1159       elfcpp::Sym<size, big_endian>* psym = &sym;
1160       unsigned char symbuf[sym_size];
1161       elfcpp::Sym<size, big_endian> sym2(symbuf);
1162       if (just_symbols)
1163         {
1164           memcpy(symbuf, p, sym_size);
1165           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1166           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1167             {
1168               // Symbol values in object files are section relative.
1169               // This is normally what we want, but since here we are
1170               // converting the symbol to absolute we need to add the
1171               // section address.  The section address in an object
1172               // file is normally zero, but people can use a linker
1173               // script to change it.
1174               sw.put_st_value(sym.get_st_value()
1175                               + relobj->section_address(orig_st_shndx));
1176             }
1177           st_shndx = elfcpp::SHN_ABS;
1178           is_ordinary = false;
1179           psym = &sym2;
1180         }
1181
1182       // Fix up visibility if object has no-export set.
1183       if (relobj->no_export()
1184           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1185         {
1186           // We may have copied symbol already above.
1187           if (psym != &sym2)
1188             {
1189               memcpy(symbuf, p, sym_size);
1190               psym = &sym2;
1191             }
1192
1193           elfcpp::STV visibility = sym2.get_st_visibility();
1194           if (visibility == elfcpp::STV_DEFAULT
1195               || visibility == elfcpp::STV_PROTECTED)
1196             {
1197               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1198               unsigned char nonvis = sym2.get_st_nonvis();
1199               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1200             }
1201         }
1202
1203       Stringpool::Key name_key;
1204       name = this->namepool_.add_with_length(name, namelen, true,
1205                                              &name_key);
1206
1207       Sized_symbol<size>* res;
1208       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1209                                   is_default_version, *psym, st_shndx,
1210                                   is_ordinary, orig_st_shndx);
1211       
1212       // If building a shared library using garbage collection, do not 
1213       // treat externally visible symbols as garbage.
1214       if (parameters->options().gc_sections() 
1215           && parameters->options().shared())
1216         this->gc_mark_symbol_for_shlib(res);
1217
1218       if (is_forced_local)
1219         this->force_local(res);
1220
1221       if (is_defined_in_discarded_section)
1222         res->set_is_defined_in_discarded_section();
1223
1224       (*sympointers)[i] = res;
1225     }
1226 }
1227
1228 // Add a symbol from a plugin-claimed file.
1229
1230 template<int size, bool big_endian>
1231 Symbol*
1232 Symbol_table::add_from_pluginobj(
1233     Sized_pluginobj<size, big_endian>* obj,
1234     const char* name,
1235     const char* ver,
1236     elfcpp::Sym<size, big_endian>* sym)
1237 {
1238   unsigned int st_shndx = sym->get_st_shndx();
1239   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1240
1241   Stringpool::Key ver_key = 0;
1242   bool is_default_version = false;
1243   bool is_forced_local = false;
1244
1245   if (ver != NULL)
1246     {
1247       ver = this->namepool_.add(ver, true, &ver_key);
1248     }
1249   // We don't want to assign a version to an undefined symbol,
1250   // even if it is listed in the version script.  FIXME: What
1251   // about a common symbol?
1252   else
1253     {
1254       if (!this->version_script_.empty()
1255           && st_shndx != elfcpp::SHN_UNDEF)
1256         {
1257           // The symbol name did not have a version, but the
1258           // version script may assign a version anyway.
1259           std::string version;
1260           bool is_global;
1261           if (this->version_script_.get_symbol_version(name, &version,
1262                                                        &is_global))
1263             {
1264               if (!is_global)
1265                 is_forced_local = true;
1266               else if (!version.empty())
1267                 {
1268                   ver = this->namepool_.add_with_length(version.c_str(),
1269                                                         version.length(),
1270                                                         true,
1271                                                         &ver_key);
1272                   is_default_version = true;
1273                 }
1274             }
1275         }
1276     }
1277
1278   Stringpool::Key name_key;
1279   name = this->namepool_.add(name, true, &name_key);
1280
1281   Sized_symbol<size>* res;
1282   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1283                               is_default_version, *sym, st_shndx,
1284                               is_ordinary, st_shndx);
1285
1286   if (is_forced_local)
1287     this->force_local(res);
1288
1289   return res;
1290 }
1291
1292 // Add all the symbols in a dynamic object to the hash table.
1293
1294 template<int size, bool big_endian>
1295 void
1296 Symbol_table::add_from_dynobj(
1297     Sized_dynobj<size, big_endian>* dynobj,
1298     const unsigned char* syms,
1299     size_t count,
1300     const char* sym_names,
1301     size_t sym_name_size,
1302     const unsigned char* versym,
1303     size_t versym_size,
1304     const std::vector<const char*>* version_map,
1305     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1306     size_t* defined)
1307 {
1308   *defined = 0;
1309
1310   gold_assert(size == parameters->target().get_size());
1311
1312   if (dynobj->just_symbols())
1313     {
1314       gold_error(_("--just-symbols does not make sense with a shared object"));
1315       return;
1316     }
1317
1318   if (versym != NULL && versym_size / 2 < count)
1319     {
1320       dynobj->error(_("too few symbol versions"));
1321       return;
1322     }
1323
1324   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1325
1326   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1327   // weak aliases.  This is necessary because if the dynamic object
1328   // provides the same variable under two names, one of which is a
1329   // weak definition, and the regular object refers to the weak
1330   // definition, we have to put both the weak definition and the
1331   // strong definition into the dynamic symbol table.  Given a weak
1332   // definition, the only way that we can find the corresponding
1333   // strong definition, if any, is to search the symbol table.
1334   std::vector<Sized_symbol<size>*> object_symbols;
1335
1336   const unsigned char* p = syms;
1337   const unsigned char* vs = versym;
1338   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1339     {
1340       elfcpp::Sym<size, big_endian> sym(p);
1341
1342       if (sympointers != NULL)
1343         (*sympointers)[i] = NULL;
1344
1345       // Ignore symbols with local binding or that have
1346       // internal or hidden visibility.
1347       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1348           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1349           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1350         continue;
1351
1352       // A protected symbol in a shared library must be treated as a
1353       // normal symbol when viewed from outside the shared library.
1354       // Implement this by overriding the visibility here.
1355       elfcpp::Sym<size, big_endian>* psym = &sym;
1356       unsigned char symbuf[sym_size];
1357       elfcpp::Sym<size, big_endian> sym2(symbuf);
1358       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1359         {
1360           memcpy(symbuf, p, sym_size);
1361           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1362           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1363           psym = &sym2;
1364         }
1365
1366       unsigned int st_name = psym->get_st_name();
1367       if (st_name >= sym_name_size)
1368         {
1369           dynobj->error(_("bad symbol name offset %u at %zu"),
1370                         st_name, i);
1371           continue;
1372         }
1373
1374       const char* name = sym_names + st_name;
1375
1376       bool is_ordinary;
1377       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1378                                                        &is_ordinary);
1379
1380       if (st_shndx != elfcpp::SHN_UNDEF)
1381         ++*defined;
1382
1383       Sized_symbol<size>* res;
1384
1385       if (versym == NULL)
1386         {
1387           Stringpool::Key name_key;
1388           name = this->namepool_.add(name, true, &name_key);
1389           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1390                                       false, *psym, st_shndx, is_ordinary,
1391                                       st_shndx);
1392         }
1393       else
1394         {
1395           // Read the version information.
1396
1397           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1398
1399           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1400           v &= elfcpp::VERSYM_VERSION;
1401
1402           // The Sun documentation says that V can be VER_NDX_LOCAL,
1403           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1404           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1405           // The old GNU linker will happily generate VER_NDX_LOCAL
1406           // for an undefined symbol.  I don't know what the Sun
1407           // linker will generate.
1408
1409           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1410               && st_shndx != elfcpp::SHN_UNDEF)
1411             {
1412               // This symbol should not be visible outside the object.
1413               continue;
1414             }
1415
1416           // At this point we are definitely going to add this symbol.
1417           Stringpool::Key name_key;
1418           name = this->namepool_.add(name, true, &name_key);
1419
1420           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1421               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1422             {
1423               // This symbol does not have a version.
1424               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1425                                           false, *psym, st_shndx, is_ordinary,
1426                                           st_shndx);
1427             }
1428           else
1429             {
1430               if (v >= version_map->size())
1431                 {
1432                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1433                                 i, v);
1434                   continue;
1435                 }
1436
1437               const char* version = (*version_map)[v];
1438               if (version == NULL)
1439                 {
1440                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1441                                 i, v);
1442                   continue;
1443                 }
1444
1445               Stringpool::Key version_key;
1446               version = this->namepool_.add(version, true, &version_key);
1447
1448               // If this is an absolute symbol, and the version name
1449               // and symbol name are the same, then this is the
1450               // version definition symbol.  These symbols exist to
1451               // support using -u to pull in particular versions.  We
1452               // do not want to record a version for them.
1453               if (st_shndx == elfcpp::SHN_ABS
1454                   && !is_ordinary
1455                   && name_key == version_key)
1456                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1457                                             false, *psym, st_shndx, is_ordinary,
1458                                             st_shndx);
1459               else
1460                 {
1461                   const bool is_default_version =
1462                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1463                   res = this->add_from_object(dynobj, name, name_key, version,
1464                                               version_key, is_default_version,
1465                                               *psym, st_shndx,
1466                                               is_ordinary, st_shndx);
1467                 }
1468             }
1469         }
1470
1471       // Note that it is possible that RES was overridden by an
1472       // earlier object, in which case it can't be aliased here.
1473       if (st_shndx != elfcpp::SHN_UNDEF
1474           && is_ordinary
1475           && psym->get_st_type() == elfcpp::STT_OBJECT
1476           && res->source() == Symbol::FROM_OBJECT
1477           && res->object() == dynobj)
1478         object_symbols.push_back(res);
1479
1480       if (sympointers != NULL)
1481         (*sympointers)[i] = res;
1482     }
1483
1484   this->record_weak_aliases(&object_symbols);
1485 }
1486
1487 // This is used to sort weak aliases.  We sort them first by section
1488 // index, then by offset, then by weak ahead of strong.
1489
1490 template<int size>
1491 class Weak_alias_sorter
1492 {
1493  public:
1494   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1495 };
1496
1497 template<int size>
1498 bool
1499 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1500                                     const Sized_symbol<size>* s2) const
1501 {
1502   bool is_ordinary;
1503   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1504   gold_assert(is_ordinary);
1505   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1506   gold_assert(is_ordinary);
1507   if (s1_shndx != s2_shndx)
1508     return s1_shndx < s2_shndx;
1509
1510   if (s1->value() != s2->value())
1511     return s1->value() < s2->value();
1512   if (s1->binding() != s2->binding())
1513     {
1514       if (s1->binding() == elfcpp::STB_WEAK)
1515         return true;
1516       if (s2->binding() == elfcpp::STB_WEAK)
1517         return false;
1518     }
1519   return std::string(s1->name()) < std::string(s2->name());
1520 }
1521
1522 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1523 // for any weak aliases, and record them so that if we add the weak
1524 // alias to the dynamic symbol table, we also add the corresponding
1525 // strong symbol.
1526
1527 template<int size>
1528 void
1529 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1530 {
1531   // Sort the vector by section index, then by offset, then by weak
1532   // ahead of strong.
1533   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1534
1535   // Walk through the vector.  For each weak definition, record
1536   // aliases.
1537   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1538          symbols->begin();
1539        p != symbols->end();
1540        ++p)
1541     {
1542       if ((*p)->binding() != elfcpp::STB_WEAK)
1543         continue;
1544
1545       // Build a circular list of weak aliases.  Each symbol points to
1546       // the next one in the circular list.
1547
1548       Sized_symbol<size>* from_sym = *p;
1549       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1550       for (q = p + 1; q != symbols->end(); ++q)
1551         {
1552           bool dummy;
1553           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1554               || (*q)->value() != from_sym->value())
1555             break;
1556
1557           this->weak_aliases_[from_sym] = *q;
1558           from_sym->set_has_alias();
1559           from_sym = *q;
1560         }
1561
1562       if (from_sym != *p)
1563         {
1564           this->weak_aliases_[from_sym] = *p;
1565           from_sym->set_has_alias();
1566         }
1567
1568       p = q - 1;
1569     }
1570 }
1571
1572 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1573 // true, then only create the symbol if there is a reference to it.
1574 // If this does not return NULL, it sets *POLDSYM to the existing
1575 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1576 // resolve the newly created symbol to the old one.  This
1577 // canonicalizes *PNAME and *PVERSION.
1578
1579 template<int size, bool big_endian>
1580 Sized_symbol<size>*
1581 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1582                                     bool only_if_ref,
1583                                     Sized_symbol<size>** poldsym,
1584                                     bool *resolve_oldsym)
1585 {
1586   *resolve_oldsym = false;
1587
1588   // If the caller didn't give us a version, see if we get one from
1589   // the version script.
1590   std::string v;
1591   bool is_default_version = false;
1592   if (*pversion == NULL)
1593     {
1594       bool is_global;
1595       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1596         {
1597           if (is_global && !v.empty())
1598             {
1599               *pversion = v.c_str();
1600               // If we get the version from a version script, then we
1601               // are also the default version.
1602               is_default_version = true;
1603             }
1604         }
1605     }
1606
1607   Symbol* oldsym;
1608   Sized_symbol<size>* sym;
1609
1610   bool add_to_table = false;
1611   typename Symbol_table_type::iterator add_loc = this->table_.end();
1612   bool add_def_to_table = false;
1613   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1614
1615   if (only_if_ref)
1616     {
1617       oldsym = this->lookup(*pname, *pversion);
1618       if (oldsym == NULL && is_default_version)
1619         oldsym = this->lookup(*pname, NULL);
1620       if (oldsym == NULL || !oldsym->is_undefined())
1621         return NULL;
1622
1623       *pname = oldsym->name();
1624       if (!is_default_version)
1625         *pversion = oldsym->version();
1626     }
1627   else
1628     {
1629       // Canonicalize NAME and VERSION.
1630       Stringpool::Key name_key;
1631       *pname = this->namepool_.add(*pname, true, &name_key);
1632
1633       Stringpool::Key version_key = 0;
1634       if (*pversion != NULL)
1635         *pversion = this->namepool_.add(*pversion, true, &version_key);
1636
1637       Symbol* const snull = NULL;
1638       std::pair<typename Symbol_table_type::iterator, bool> ins =
1639         this->table_.insert(std::make_pair(std::make_pair(name_key,
1640                                                           version_key),
1641                                            snull));
1642
1643       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1644         std::make_pair(this->table_.end(), false);
1645       if (is_default_version)
1646         {
1647           const Stringpool::Key vnull = 0;
1648           insdefault =
1649             this->table_.insert(std::make_pair(std::make_pair(name_key,
1650                                                               vnull),
1651                                                snull));
1652         }
1653
1654       if (!ins.second)
1655         {
1656           // We already have a symbol table entry for NAME/VERSION.
1657           oldsym = ins.first->second;
1658           gold_assert(oldsym != NULL);
1659
1660           if (is_default_version)
1661             {
1662               Sized_symbol<size>* soldsym =
1663                 this->get_sized_symbol<size>(oldsym);
1664               this->define_default_version<size, big_endian>(soldsym,
1665                                                              insdefault.second,
1666                                                              insdefault.first);
1667             }
1668         }
1669       else
1670         {
1671           // We haven't seen this symbol before.
1672           gold_assert(ins.first->second == NULL);
1673
1674           add_to_table = true;
1675           add_loc = ins.first;
1676
1677           if (is_default_version && !insdefault.second)
1678             {
1679               // We are adding NAME/VERSION, and it is the default
1680               // version.  We already have an entry for NAME/NULL.
1681               oldsym = insdefault.first->second;
1682               *resolve_oldsym = true;
1683             }
1684           else
1685             {
1686               oldsym = NULL;
1687
1688               if (is_default_version)
1689                 {
1690                   add_def_to_table = true;
1691                   add_def_loc = insdefault.first;
1692                 }
1693             }
1694         }
1695     }
1696
1697   const Target& target = parameters->target();
1698   if (!target.has_make_symbol())
1699     sym = new Sized_symbol<size>();
1700   else
1701     {
1702       Sized_target<size, big_endian>* sized_target =
1703         parameters->sized_target<size, big_endian>();
1704       sym = sized_target->make_symbol();
1705       if (sym == NULL)
1706         return NULL;
1707     }
1708
1709   if (add_to_table)
1710     add_loc->second = sym;
1711   else
1712     gold_assert(oldsym != NULL);
1713
1714   if (add_def_to_table)
1715     add_def_loc->second = sym;
1716
1717   *poldsym = this->get_sized_symbol<size>(oldsym);
1718
1719   return sym;
1720 }
1721
1722 // Define a symbol based on an Output_data.
1723
1724 Symbol*
1725 Symbol_table::define_in_output_data(const char* name,
1726                                     const char* version,
1727                                     Defined defined,
1728                                     Output_data* od,
1729                                     uint64_t value,
1730                                     uint64_t symsize,
1731                                     elfcpp::STT type,
1732                                     elfcpp::STB binding,
1733                                     elfcpp::STV visibility,
1734                                     unsigned char nonvis,
1735                                     bool offset_is_from_end,
1736                                     bool only_if_ref)
1737 {
1738   if (parameters->target().get_size() == 32)
1739     {
1740 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1741       return this->do_define_in_output_data<32>(name, version, defined, od,
1742                                                 value, symsize, type, binding,
1743                                                 visibility, nonvis,
1744                                                 offset_is_from_end,
1745                                                 only_if_ref);
1746 #else
1747       gold_unreachable();
1748 #endif
1749     }
1750   else if (parameters->target().get_size() == 64)
1751     {
1752 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1753       return this->do_define_in_output_data<64>(name, version, defined, od,
1754                                                 value, symsize, type, binding,
1755                                                 visibility, nonvis,
1756                                                 offset_is_from_end,
1757                                                 only_if_ref);
1758 #else
1759       gold_unreachable();
1760 #endif
1761     }
1762   else
1763     gold_unreachable();
1764 }
1765
1766 // Define a symbol in an Output_data, sized version.
1767
1768 template<int size>
1769 Sized_symbol<size>*
1770 Symbol_table::do_define_in_output_data(
1771     const char* name,
1772     const char* version,
1773     Defined defined,
1774     Output_data* od,
1775     typename elfcpp::Elf_types<size>::Elf_Addr value,
1776     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1777     elfcpp::STT type,
1778     elfcpp::STB binding,
1779     elfcpp::STV visibility,
1780     unsigned char nonvis,
1781     bool offset_is_from_end,
1782     bool only_if_ref)
1783 {
1784   Sized_symbol<size>* sym;
1785   Sized_symbol<size>* oldsym;
1786   bool resolve_oldsym;
1787
1788   if (parameters->target().is_big_endian())
1789     {
1790 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1791       sym = this->define_special_symbol<size, true>(&name, &version,
1792                                                     only_if_ref, &oldsym,
1793                                                     &resolve_oldsym);
1794 #else
1795       gold_unreachable();
1796 #endif
1797     }
1798   else
1799     {
1800 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1801       sym = this->define_special_symbol<size, false>(&name, &version,
1802                                                      only_if_ref, &oldsym,
1803                                                      &resolve_oldsym);
1804 #else
1805       gold_unreachable();
1806 #endif
1807     }
1808
1809   if (sym == NULL)
1810     return NULL;
1811
1812   sym->init_output_data(name, version, od, value, symsize, type, binding,
1813                         visibility, nonvis, offset_is_from_end);
1814
1815   if (oldsym == NULL)
1816     {
1817       if (binding == elfcpp::STB_LOCAL
1818           || this->version_script_.symbol_is_local(name))
1819         this->force_local(sym);
1820       else if (version != NULL)
1821         sym->set_is_default();
1822       return sym;
1823     }
1824
1825   if (Symbol_table::should_override_with_special(oldsym, defined))
1826     this->override_with_special(oldsym, sym);
1827
1828   if (resolve_oldsym)
1829     return sym;
1830   else
1831     {
1832       delete sym;
1833       return oldsym;
1834     }
1835 }
1836
1837 // Define a symbol based on an Output_segment.
1838
1839 Symbol*
1840 Symbol_table::define_in_output_segment(const char* name,
1841                                        const char* version,
1842                                        Defined defined,
1843                                        Output_segment* os,
1844                                        uint64_t value,
1845                                        uint64_t symsize,
1846                                        elfcpp::STT type,
1847                                        elfcpp::STB binding,
1848                                        elfcpp::STV visibility,
1849                                        unsigned char nonvis,
1850                                        Symbol::Segment_offset_base offset_base,
1851                                        bool only_if_ref)
1852 {
1853   if (parameters->target().get_size() == 32)
1854     {
1855 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1856       return this->do_define_in_output_segment<32>(name, version, defined, os,
1857                                                    value, symsize, type,
1858                                                    binding, visibility, nonvis,
1859                                                    offset_base, only_if_ref);
1860 #else
1861       gold_unreachable();
1862 #endif
1863     }
1864   else if (parameters->target().get_size() == 64)
1865     {
1866 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1867       return this->do_define_in_output_segment<64>(name, version, defined, os,
1868                                                    value, symsize, type,
1869                                                    binding, visibility, nonvis,
1870                                                    offset_base, only_if_ref);
1871 #else
1872       gold_unreachable();
1873 #endif
1874     }
1875   else
1876     gold_unreachable();
1877 }
1878
1879 // Define a symbol in an Output_segment, sized version.
1880
1881 template<int size>
1882 Sized_symbol<size>*
1883 Symbol_table::do_define_in_output_segment(
1884     const char* name,
1885     const char* version,
1886     Defined defined,
1887     Output_segment* os,
1888     typename elfcpp::Elf_types<size>::Elf_Addr value,
1889     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1890     elfcpp::STT type,
1891     elfcpp::STB binding,
1892     elfcpp::STV visibility,
1893     unsigned char nonvis,
1894     Symbol::Segment_offset_base offset_base,
1895     bool only_if_ref)
1896 {
1897   Sized_symbol<size>* sym;
1898   Sized_symbol<size>* oldsym;
1899   bool resolve_oldsym;
1900
1901   if (parameters->target().is_big_endian())
1902     {
1903 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1904       sym = this->define_special_symbol<size, true>(&name, &version,
1905                                                     only_if_ref, &oldsym,
1906                                                     &resolve_oldsym);
1907 #else
1908       gold_unreachable();
1909 #endif
1910     }
1911   else
1912     {
1913 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1914       sym = this->define_special_symbol<size, false>(&name, &version,
1915                                                      only_if_ref, &oldsym,
1916                                                      &resolve_oldsym);
1917 #else
1918       gold_unreachable();
1919 #endif
1920     }
1921
1922   if (sym == NULL)
1923     return NULL;
1924
1925   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1926                            visibility, nonvis, offset_base);
1927
1928   if (oldsym == NULL)
1929     {
1930       if (binding == elfcpp::STB_LOCAL
1931           || this->version_script_.symbol_is_local(name))
1932         this->force_local(sym);
1933       else if (version != NULL)
1934         sym->set_is_default();
1935       return sym;
1936     }
1937
1938   if (Symbol_table::should_override_with_special(oldsym, defined))
1939     this->override_with_special(oldsym, sym);
1940
1941   if (resolve_oldsym)
1942     return sym;
1943   else
1944     {
1945       delete sym;
1946       return oldsym;
1947     }
1948 }
1949
1950 // Define a special symbol with a constant value.  It is a multiple
1951 // definition error if this symbol is already defined.
1952
1953 Symbol*
1954 Symbol_table::define_as_constant(const char* name,
1955                                  const char* version,
1956                                  Defined defined,
1957                                  uint64_t value,
1958                                  uint64_t symsize,
1959                                  elfcpp::STT type,
1960                                  elfcpp::STB binding,
1961                                  elfcpp::STV visibility,
1962                                  unsigned char nonvis,
1963                                  bool only_if_ref,
1964                                  bool force_override)
1965 {
1966   if (parameters->target().get_size() == 32)
1967     {
1968 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1969       return this->do_define_as_constant<32>(name, version, defined, value,
1970                                              symsize, type, binding,
1971                                              visibility, nonvis, only_if_ref,
1972                                              force_override);
1973 #else
1974       gold_unreachable();
1975 #endif
1976     }
1977   else if (parameters->target().get_size() == 64)
1978     {
1979 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1980       return this->do_define_as_constant<64>(name, version, defined, value,
1981                                              symsize, type, binding,
1982                                              visibility, nonvis, only_if_ref,
1983                                              force_override);
1984 #else
1985       gold_unreachable();
1986 #endif
1987     }
1988   else
1989     gold_unreachable();
1990 }
1991
1992 // Define a symbol as a constant, sized version.
1993
1994 template<int size>
1995 Sized_symbol<size>*
1996 Symbol_table::do_define_as_constant(
1997     const char* name,
1998     const char* version,
1999     Defined defined,
2000     typename elfcpp::Elf_types<size>::Elf_Addr value,
2001     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
2002     elfcpp::STT type,
2003     elfcpp::STB binding,
2004     elfcpp::STV visibility,
2005     unsigned char nonvis,
2006     bool only_if_ref,
2007     bool force_override)
2008 {
2009   Sized_symbol<size>* sym;
2010   Sized_symbol<size>* oldsym;
2011   bool resolve_oldsym;
2012
2013   if (parameters->target().is_big_endian())
2014     {
2015 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2016       sym = this->define_special_symbol<size, true>(&name, &version,
2017                                                     only_if_ref, &oldsym,
2018                                                     &resolve_oldsym);
2019 #else
2020       gold_unreachable();
2021 #endif
2022     }
2023   else
2024     {
2025 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2026       sym = this->define_special_symbol<size, false>(&name, &version,
2027                                                      only_if_ref, &oldsym,
2028                                                      &resolve_oldsym);
2029 #else
2030       gold_unreachable();
2031 #endif
2032     }
2033
2034   if (sym == NULL)
2035     return NULL;
2036
2037   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2038                      nonvis);
2039
2040   if (oldsym == NULL)
2041     {
2042       // Version symbols are absolute symbols with name == version.
2043       // We don't want to force them to be local.
2044       if ((version == NULL
2045            || name != version
2046            || value != 0)
2047           && (binding == elfcpp::STB_LOCAL
2048               || this->version_script_.symbol_is_local(name)))
2049         this->force_local(sym);
2050       else if (version != NULL
2051                && (name != version || value != 0))
2052         sym->set_is_default();
2053       return sym;
2054     }
2055
2056   if (force_override
2057       || Symbol_table::should_override_with_special(oldsym, defined))
2058     this->override_with_special(oldsym, sym);
2059
2060   if (resolve_oldsym)
2061     return sym;
2062   else
2063     {
2064       delete sym;
2065       return oldsym;
2066     }
2067 }
2068
2069 // Define a set of symbols in output sections.
2070
2071 void
2072 Symbol_table::define_symbols(const Layout* layout, int count,
2073                              const Define_symbol_in_section* p,
2074                              bool only_if_ref)
2075 {
2076   for (int i = 0; i < count; ++i, ++p)
2077     {
2078       Output_section* os = layout->find_output_section(p->output_section);
2079       if (os != NULL)
2080         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2081                                     p->size, p->type, p->binding,
2082                                     p->visibility, p->nonvis,
2083                                     p->offset_is_from_end,
2084                                     only_if_ref || p->only_if_ref);
2085       else
2086         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2087                                  p->type, p->binding, p->visibility, p->nonvis,
2088                                  only_if_ref || p->only_if_ref,
2089                                  false);
2090     }
2091 }
2092
2093 // Define a set of symbols in output segments.
2094
2095 void
2096 Symbol_table::define_symbols(const Layout* layout, int count,
2097                              const Define_symbol_in_segment* p,
2098                              bool only_if_ref)
2099 {
2100   for (int i = 0; i < count; ++i, ++p)
2101     {
2102       Output_segment* os = layout->find_output_segment(p->segment_type,
2103                                                        p->segment_flags_set,
2104                                                        p->segment_flags_clear);
2105       if (os != NULL)
2106         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2107                                        p->size, p->type, p->binding,
2108                                        p->visibility, p->nonvis,
2109                                        p->offset_base,
2110                                        only_if_ref || p->only_if_ref);
2111       else
2112         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2113                                  p->type, p->binding, p->visibility, p->nonvis,
2114                                  only_if_ref || p->only_if_ref,
2115                                  false);
2116     }
2117 }
2118
2119 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2120 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2121 // the offset within POSD.
2122
2123 template<int size>
2124 void
2125 Symbol_table::define_with_copy_reloc(
2126     Sized_symbol<size>* csym,
2127     Output_data* posd,
2128     typename elfcpp::Elf_types<size>::Elf_Addr value)
2129 {
2130   gold_assert(csym->is_from_dynobj());
2131   gold_assert(!csym->is_copied_from_dynobj());
2132   Object* object = csym->object();
2133   gold_assert(object->is_dynamic());
2134   Dynobj* dynobj = static_cast<Dynobj*>(object);
2135
2136   // Our copied variable has to override any variable in a shared
2137   // library.
2138   elfcpp::STB binding = csym->binding();
2139   if (binding == elfcpp::STB_WEAK)
2140     binding = elfcpp::STB_GLOBAL;
2141
2142   this->define_in_output_data(csym->name(), csym->version(), COPY,
2143                               posd, value, csym->symsize(),
2144                               csym->type(), binding,
2145                               csym->visibility(), csym->nonvis(),
2146                               false, false);
2147
2148   csym->set_is_copied_from_dynobj();
2149   csym->set_needs_dynsym_entry();
2150
2151   this->copied_symbol_dynobjs_[csym] = dynobj;
2152
2153   // We have now defined all aliases, but we have not entered them all
2154   // in the copied_symbol_dynobjs_ map.
2155   if (csym->has_alias())
2156     {
2157       Symbol* sym = csym;
2158       while (true)
2159         {
2160           sym = this->weak_aliases_[sym];
2161           if (sym == csym)
2162             break;
2163           gold_assert(sym->output_data() == posd);
2164
2165           sym->set_is_copied_from_dynobj();
2166           this->copied_symbol_dynobjs_[sym] = dynobj;
2167         }
2168     }
2169 }
2170
2171 // SYM is defined using a COPY reloc.  Return the dynamic object where
2172 // the original definition was found.
2173
2174 Dynobj*
2175 Symbol_table::get_copy_source(const Symbol* sym) const
2176 {
2177   gold_assert(sym->is_copied_from_dynobj());
2178   Copied_symbol_dynobjs::const_iterator p =
2179     this->copied_symbol_dynobjs_.find(sym);
2180   gold_assert(p != this->copied_symbol_dynobjs_.end());
2181   return p->second;
2182 }
2183
2184 // Add any undefined symbols named on the command line.
2185
2186 void
2187 Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
2188 {
2189   if (parameters->options().any_undefined()
2190       || layout->script_options()->any_unreferenced())
2191     {
2192       if (parameters->target().get_size() == 32)
2193         {
2194 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2195           this->do_add_undefined_symbols_from_command_line<32>(layout);
2196 #else
2197           gold_unreachable();
2198 #endif
2199         }
2200       else if (parameters->target().get_size() == 64)
2201         {
2202 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2203           this->do_add_undefined_symbols_from_command_line<64>(layout);
2204 #else
2205           gold_unreachable();
2206 #endif
2207         }
2208       else
2209         gold_unreachable();
2210     }
2211 }
2212
2213 template<int size>
2214 void
2215 Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
2216 {
2217   for (options::String_set::const_iterator p =
2218          parameters->options().undefined_begin();
2219        p != parameters->options().undefined_end();
2220        ++p)
2221     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2222
2223   for (Script_options::referenced_const_iterator p =
2224          layout->script_options()->referenced_begin();
2225        p != layout->script_options()->referenced_end();
2226        ++p)
2227     this->add_undefined_symbol_from_command_line<size>(p->c_str());
2228 }
2229
2230 template<int size>
2231 void
2232 Symbol_table::add_undefined_symbol_from_command_line(const char* name)
2233 {
2234   if (this->lookup(name) != NULL)
2235     return;
2236
2237   const char* version = NULL;
2238
2239   Sized_symbol<size>* sym;
2240   Sized_symbol<size>* oldsym;
2241   bool resolve_oldsym;
2242   if (parameters->target().is_big_endian())
2243     {
2244 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2245       sym = this->define_special_symbol<size, true>(&name, &version,
2246                                                     false, &oldsym,
2247                                                     &resolve_oldsym);
2248 #else
2249       gold_unreachable();
2250 #endif
2251     }
2252   else
2253     {
2254 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2255       sym = this->define_special_symbol<size, false>(&name, &version,
2256                                                      false, &oldsym,
2257                                                      &resolve_oldsym);
2258 #else
2259       gold_unreachable();
2260 #endif
2261     }
2262
2263   gold_assert(oldsym == NULL);
2264
2265   sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2266                       elfcpp::STV_DEFAULT, 0);
2267   ++this->saw_undefined_;
2268 }
2269
2270 // Set the dynamic symbol indexes.  INDEX is the index of the first
2271 // global dynamic symbol.  Pointers to the symbols are stored into the
2272 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2273 // updated dynamic symbol index.
2274
2275 unsigned int
2276 Symbol_table::set_dynsym_indexes(unsigned int index,
2277                                  std::vector<Symbol*>* syms,
2278                                  Stringpool* dynpool,
2279                                  Versions* versions)
2280 {
2281   for (Symbol_table_type::iterator p = this->table_.begin();
2282        p != this->table_.end();
2283        ++p)
2284     {
2285       Symbol* sym = p->second;
2286
2287       // Note that SYM may already have a dynamic symbol index, since
2288       // some symbols appear more than once in the symbol table, with
2289       // and without a version.
2290
2291       if (!sym->should_add_dynsym_entry(this))
2292         sym->set_dynsym_index(-1U);
2293       else if (!sym->has_dynsym_index())
2294         {
2295           sym->set_dynsym_index(index);
2296           ++index;
2297           syms->push_back(sym);
2298           dynpool->add(sym->name(), false, NULL);
2299
2300           // Record any version information.
2301           if (sym->version() != NULL)
2302             versions->record_version(this, dynpool, sym);
2303
2304           // If the symbol is defined in a dynamic object and is
2305           // referenced in a regular object, then mark the dynamic
2306           // object as needed.  This is used to implement --as-needed.
2307           if (sym->is_from_dynobj() && sym->in_reg())
2308             sym->object()->set_is_needed();
2309         }
2310     }
2311
2312   // Finish up the versions.  In some cases this may add new dynamic
2313   // symbols.
2314   index = versions->finalize(this, index, syms);
2315
2316   return index;
2317 }
2318
2319 // Set the final values for all the symbols.  The index of the first
2320 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2321 // file offset OFF.  Add their names to POOL.  Return the new file
2322 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2323
2324 off_t
2325 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2326                        size_t dyncount, Stringpool* pool,
2327                        unsigned int *plocal_symcount)
2328 {
2329   off_t ret;
2330
2331   gold_assert(*plocal_symcount != 0);
2332   this->first_global_index_ = *plocal_symcount;
2333
2334   this->dynamic_offset_ = dynoff;
2335   this->first_dynamic_global_index_ = dyn_global_index;
2336   this->dynamic_count_ = dyncount;
2337
2338   if (parameters->target().get_size() == 32)
2339     {
2340 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2341       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2342 #else
2343       gold_unreachable();
2344 #endif
2345     }
2346   else if (parameters->target().get_size() == 64)
2347     {
2348 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2349       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2350 #else
2351       gold_unreachable();
2352 #endif
2353     }
2354   else
2355     gold_unreachable();
2356
2357   // Now that we have the final symbol table, we can reliably note
2358   // which symbols should get warnings.
2359   this->warnings_.note_warnings(this);
2360
2361   return ret;
2362 }
2363
2364 // SYM is going into the symbol table at *PINDEX.  Add the name to
2365 // POOL, update *PINDEX and *POFF.
2366
2367 template<int size>
2368 void
2369 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2370                                   unsigned int* pindex, off_t* poff)
2371 {
2372   sym->set_symtab_index(*pindex);
2373   pool->add(sym->name(), false, NULL);
2374   ++*pindex;
2375   *poff += elfcpp::Elf_sizes<size>::sym_size;
2376 }
2377
2378 // Set the final value for all the symbols.  This is called after
2379 // Layout::finalize, so all the output sections have their final
2380 // address.
2381
2382 template<int size>
2383 off_t
2384 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2385                              unsigned int* plocal_symcount)
2386 {
2387   off = align_address(off, size >> 3);
2388   this->offset_ = off;
2389
2390   unsigned int index = *plocal_symcount;
2391   const unsigned int orig_index = index;
2392
2393   // First do all the symbols which have been forced to be local, as
2394   // they must appear before all global symbols.
2395   for (Forced_locals::iterator p = this->forced_locals_.begin();
2396        p != this->forced_locals_.end();
2397        ++p)
2398     {
2399       Symbol* sym = *p;
2400       gold_assert(sym->is_forced_local());
2401       if (this->sized_finalize_symbol<size>(sym))
2402         {
2403           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2404           ++*plocal_symcount;
2405         }
2406     }
2407
2408   // Now do all the remaining symbols.
2409   for (Symbol_table_type::iterator p = this->table_.begin();
2410        p != this->table_.end();
2411        ++p)
2412     {
2413       Symbol* sym = p->second;
2414       if (this->sized_finalize_symbol<size>(sym))
2415         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2416     }
2417
2418   this->output_count_ = index - orig_index;
2419
2420   return off;
2421 }
2422
2423 // Compute the final value of SYM and store status in location PSTATUS.
2424 // During relaxation, this may be called multiple times for a symbol to
2425 // compute its would-be final value in each relaxation pass.
2426
2427 template<int size>
2428 typename Sized_symbol<size>::Value_type
2429 Symbol_table::compute_final_value(
2430     const Sized_symbol<size>* sym,
2431     Compute_final_value_status* pstatus) const
2432 {
2433   typedef typename Sized_symbol<size>::Value_type Value_type;
2434   Value_type value;
2435
2436   switch (sym->source())
2437     {
2438     case Symbol::FROM_OBJECT:
2439       {
2440         bool is_ordinary;
2441         unsigned int shndx = sym->shndx(&is_ordinary);
2442
2443         if (!is_ordinary
2444             && shndx != elfcpp::SHN_ABS
2445             && !Symbol::is_common_shndx(shndx))
2446           {
2447             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2448             return 0;
2449           }
2450
2451         Object* symobj = sym->object();
2452         if (symobj->is_dynamic())
2453           {
2454             value = 0;
2455             shndx = elfcpp::SHN_UNDEF;
2456           }
2457         else if (symobj->pluginobj() != NULL)
2458           {
2459             value = 0;
2460             shndx = elfcpp::SHN_UNDEF;
2461           }
2462         else if (shndx == elfcpp::SHN_UNDEF)
2463           value = 0;
2464         else if (!is_ordinary
2465                  && (shndx == elfcpp::SHN_ABS
2466                      || Symbol::is_common_shndx(shndx)))
2467           value = sym->value();
2468         else
2469           {
2470             Relobj* relobj = static_cast<Relobj*>(symobj);
2471             Output_section* os = relobj->output_section(shndx);
2472
2473             if (this->is_section_folded(relobj, shndx))
2474               {
2475                 gold_assert(os == NULL);
2476                 // Get the os of the section it is folded onto.
2477                 Section_id folded = this->icf_->get_folded_section(relobj,
2478                                                                    shndx);
2479                 gold_assert(folded.first != NULL);
2480                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2481                 unsigned folded_shndx = folded.second;
2482
2483                 os = folded_obj->output_section(folded_shndx);  
2484                 gold_assert(os != NULL);
2485
2486                 // Replace (relobj, shndx) with canonical ICF input section.
2487                 shndx = folded_shndx;
2488                 relobj = folded_obj;
2489               }
2490
2491             uint64_t secoff64 = relobj->output_section_offset(shndx);
2492             if (os == NULL)
2493               {
2494                 bool static_or_reloc = (parameters->doing_static_link() ||
2495                                         parameters->options().relocatable());
2496                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2497
2498                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2499                 return 0;
2500               }
2501
2502             if (secoff64 == -1ULL)
2503               {
2504                 // The section needs special handling (e.g., a merge section).
2505
2506                 value = os->output_address(relobj, shndx, sym->value());
2507               }
2508             else
2509               {
2510                 Value_type secoff =
2511                   convert_types<Value_type, uint64_t>(secoff64);
2512                 if (sym->type() == elfcpp::STT_TLS)
2513                   value = sym->value() + os->tls_offset() + secoff;
2514                 else
2515                   value = sym->value() + os->address() + secoff;
2516               }
2517           }
2518       }
2519       break;
2520
2521     case Symbol::IN_OUTPUT_DATA:
2522       {
2523         Output_data* od = sym->output_data();
2524         value = sym->value();
2525         if (sym->type() != elfcpp::STT_TLS)
2526           value += od->address();
2527         else
2528           {
2529             Output_section* os = od->output_section();
2530             gold_assert(os != NULL);
2531             value += os->tls_offset() + (od->address() - os->address());
2532           }
2533         if (sym->offset_is_from_end())
2534           value += od->data_size();
2535       }
2536       break;
2537
2538     case Symbol::IN_OUTPUT_SEGMENT:
2539       {
2540         Output_segment* os = sym->output_segment();
2541         value = sym->value();
2542         if (sym->type() != elfcpp::STT_TLS)
2543           value += os->vaddr();
2544         switch (sym->offset_base())
2545           {
2546           case Symbol::SEGMENT_START:
2547             break;
2548           case Symbol::SEGMENT_END:
2549             value += os->memsz();
2550             break;
2551           case Symbol::SEGMENT_BSS:
2552             value += os->filesz();
2553             break;
2554           default:
2555             gold_unreachable();
2556           }
2557       }
2558       break;
2559
2560     case Symbol::IS_CONSTANT:
2561       value = sym->value();
2562       break;
2563
2564     case Symbol::IS_UNDEFINED:
2565       value = 0;
2566       break;
2567
2568     default:
2569       gold_unreachable();
2570     }
2571
2572   *pstatus = CFVS_OK;
2573   return value;
2574 }
2575
2576 // Finalize the symbol SYM.  This returns true if the symbol should be
2577 // added to the symbol table, false otherwise.
2578
2579 template<int size>
2580 bool
2581 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2582 {
2583   typedef typename Sized_symbol<size>::Value_type Value_type;
2584
2585   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2586
2587   // The default version of a symbol may appear twice in the symbol
2588   // table.  We only need to finalize it once.
2589   if (sym->has_symtab_index())
2590     return false;
2591
2592   if (!sym->in_reg())
2593     {
2594       gold_assert(!sym->has_symtab_index());
2595       sym->set_symtab_index(-1U);
2596       gold_assert(sym->dynsym_index() == -1U);
2597       return false;
2598     }
2599
2600   // Compute final symbol value.
2601   Compute_final_value_status status;
2602   Value_type value = this->compute_final_value(sym, &status);
2603
2604   switch (status)
2605     {
2606     case CFVS_OK:
2607       break;
2608     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2609       {
2610         bool is_ordinary;
2611         unsigned int shndx = sym->shndx(&is_ordinary);
2612         gold_error(_("%s: unsupported symbol section 0x%x"),
2613                    sym->demangled_name().c_str(), shndx);
2614       }
2615       break;
2616     case CFVS_NO_OUTPUT_SECTION:
2617       sym->set_symtab_index(-1U);
2618       return false;
2619     default:
2620       gold_unreachable();
2621     }
2622
2623   sym->set_value(value);
2624
2625   if (parameters->options().strip_all()
2626       || !parameters->options().should_retain_symbol(sym->name()))
2627     {
2628       sym->set_symtab_index(-1U);
2629       return false;
2630     }
2631
2632   return true;
2633 }
2634
2635 // Write out the global symbols.
2636
2637 void
2638 Symbol_table::write_globals(const Stringpool* sympool,
2639                             const Stringpool* dynpool,
2640                             Output_symtab_xindex* symtab_xindex,
2641                             Output_symtab_xindex* dynsym_xindex,
2642                             Output_file* of) const
2643 {
2644   switch (parameters->size_and_endianness())
2645     {
2646 #ifdef HAVE_TARGET_32_LITTLE
2647     case Parameters::TARGET_32_LITTLE:
2648       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2649                                            dynsym_xindex, of);
2650       break;
2651 #endif
2652 #ifdef HAVE_TARGET_32_BIG
2653     case Parameters::TARGET_32_BIG:
2654       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2655                                           dynsym_xindex, of);
2656       break;
2657 #endif
2658 #ifdef HAVE_TARGET_64_LITTLE
2659     case Parameters::TARGET_64_LITTLE:
2660       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2661                                            dynsym_xindex, of);
2662       break;
2663 #endif
2664 #ifdef HAVE_TARGET_64_BIG
2665     case Parameters::TARGET_64_BIG:
2666       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2667                                           dynsym_xindex, of);
2668       break;
2669 #endif
2670     default:
2671       gold_unreachable();
2672     }
2673 }
2674
2675 // Write out the global symbols.
2676
2677 template<int size, bool big_endian>
2678 void
2679 Symbol_table::sized_write_globals(const Stringpool* sympool,
2680                                   const Stringpool* dynpool,
2681                                   Output_symtab_xindex* symtab_xindex,
2682                                   Output_symtab_xindex* dynsym_xindex,
2683                                   Output_file* of) const
2684 {
2685   const Target& target = parameters->target();
2686
2687   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2688
2689   const unsigned int output_count = this->output_count_;
2690   const section_size_type oview_size = output_count * sym_size;
2691   const unsigned int first_global_index = this->first_global_index_;
2692   unsigned char* psyms;
2693   if (this->offset_ == 0 || output_count == 0)
2694     psyms = NULL;
2695   else
2696     psyms = of->get_output_view(this->offset_, oview_size);
2697
2698   const unsigned int dynamic_count = this->dynamic_count_;
2699   const section_size_type dynamic_size = dynamic_count * sym_size;
2700   const unsigned int first_dynamic_global_index =
2701     this->first_dynamic_global_index_;
2702   unsigned char* dynamic_view;
2703   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2704     dynamic_view = NULL;
2705   else
2706     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2707
2708   for (Symbol_table_type::const_iterator p = this->table_.begin();
2709        p != this->table_.end();
2710        ++p)
2711     {
2712       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2713
2714       // Possibly warn about unresolved symbols in shared libraries.
2715       this->warn_about_undefined_dynobj_symbol(sym);
2716
2717       unsigned int sym_index = sym->symtab_index();
2718       unsigned int dynsym_index;
2719       if (dynamic_view == NULL)
2720         dynsym_index = -1U;
2721       else
2722         dynsym_index = sym->dynsym_index();
2723
2724       if (sym_index == -1U && dynsym_index == -1U)
2725         {
2726           // This symbol is not included in the output file.
2727           continue;
2728         }
2729
2730       unsigned int shndx;
2731       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2732       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2733       elfcpp::STB binding = sym->binding();
2734       switch (sym->source())
2735         {
2736         case Symbol::FROM_OBJECT:
2737           {
2738             bool is_ordinary;
2739             unsigned int in_shndx = sym->shndx(&is_ordinary);
2740
2741             if (!is_ordinary
2742                 && in_shndx != elfcpp::SHN_ABS
2743                 && !Symbol::is_common_shndx(in_shndx))
2744               {
2745                 gold_error(_("%s: unsupported symbol section 0x%x"),
2746                            sym->demangled_name().c_str(), in_shndx);
2747                 shndx = in_shndx;
2748               }
2749             else
2750               {
2751                 Object* symobj = sym->object();
2752                 if (symobj->is_dynamic())
2753                   {
2754                     if (sym->needs_dynsym_value())
2755                       dynsym_value = target.dynsym_value(sym);
2756                     shndx = elfcpp::SHN_UNDEF;
2757                     if (sym->is_undef_binding_weak())
2758                       binding = elfcpp::STB_WEAK;
2759                   }
2760                 else if (symobj->pluginobj() != NULL)
2761                   shndx = elfcpp::SHN_UNDEF;
2762                 else if (in_shndx == elfcpp::SHN_UNDEF
2763                          || (!is_ordinary
2764                              && (in_shndx == elfcpp::SHN_ABS
2765                                  || Symbol::is_common_shndx(in_shndx))))
2766                   shndx = in_shndx;
2767                 else
2768                   {
2769                     Relobj* relobj = static_cast<Relobj*>(symobj);
2770                     Output_section* os = relobj->output_section(in_shndx);
2771                     if (this->is_section_folded(relobj, in_shndx))
2772                       {
2773                         // This global symbol must be written out even though
2774                         // it is folded.
2775                         // Get the os of the section it is folded onto.
2776                         Section_id folded =
2777                              this->icf_->get_folded_section(relobj, in_shndx);
2778                         gold_assert(folded.first !=NULL);
2779                         Relobj* folded_obj = 
2780                           reinterpret_cast<Relobj*>(folded.first);
2781                         os = folded_obj->output_section(folded.second);  
2782                         gold_assert(os != NULL);
2783                       }
2784                     gold_assert(os != NULL);
2785                     shndx = os->out_shndx();
2786
2787                     if (shndx >= elfcpp::SHN_LORESERVE)
2788                       {
2789                         if (sym_index != -1U)
2790                           symtab_xindex->add(sym_index, shndx);
2791                         if (dynsym_index != -1U)
2792                           dynsym_xindex->add(dynsym_index, shndx);
2793                         shndx = elfcpp::SHN_XINDEX;
2794                       }
2795
2796                     // In object files symbol values are section
2797                     // relative.
2798                     if (parameters->options().relocatable())
2799                       sym_value -= os->address();
2800                   }
2801               }
2802           }
2803           break;
2804
2805         case Symbol::IN_OUTPUT_DATA:
2806           shndx = sym->output_data()->out_shndx();
2807           if (shndx >= elfcpp::SHN_LORESERVE)
2808             {
2809               if (sym_index != -1U)
2810                 symtab_xindex->add(sym_index, shndx);
2811               if (dynsym_index != -1U)
2812                 dynsym_xindex->add(dynsym_index, shndx);
2813               shndx = elfcpp::SHN_XINDEX;
2814             }
2815           break;
2816
2817         case Symbol::IN_OUTPUT_SEGMENT:
2818           shndx = elfcpp::SHN_ABS;
2819           break;
2820
2821         case Symbol::IS_CONSTANT:
2822           shndx = elfcpp::SHN_ABS;
2823           break;
2824
2825         case Symbol::IS_UNDEFINED:
2826           shndx = elfcpp::SHN_UNDEF;
2827           break;
2828
2829         default:
2830           gold_unreachable();
2831         }
2832
2833       if (sym_index != -1U)
2834         {
2835           sym_index -= first_global_index;
2836           gold_assert(sym_index < output_count);
2837           unsigned char* ps = psyms + (sym_index * sym_size);
2838           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2839                                                      binding, sympool, ps);
2840         }
2841
2842       if (dynsym_index != -1U)
2843         {
2844           dynsym_index -= first_dynamic_global_index;
2845           gold_assert(dynsym_index < dynamic_count);
2846           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2847           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2848                                                      binding, dynpool, pd);
2849         }
2850     }
2851
2852   of->write_output_view(this->offset_, oview_size, psyms);
2853   if (dynamic_view != NULL)
2854     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2855 }
2856
2857 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2858 // strtab holding the name.
2859
2860 template<int size, bool big_endian>
2861 void
2862 Symbol_table::sized_write_symbol(
2863     Sized_symbol<size>* sym,
2864     typename elfcpp::Elf_types<size>::Elf_Addr value,
2865     unsigned int shndx,
2866     elfcpp::STB binding,
2867     const Stringpool* pool,
2868     unsigned char* p) const
2869 {
2870   elfcpp::Sym_write<size, big_endian> osym(p);
2871   osym.put_st_name(pool->get_offset(sym->name()));
2872   osym.put_st_value(value);
2873   // Use a symbol size of zero for undefined symbols from shared libraries.
2874   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2875     osym.put_st_size(0);
2876   else
2877     osym.put_st_size(sym->symsize());
2878   elfcpp::STT type = sym->type();
2879   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2880   if (type == elfcpp::STT_GNU_IFUNC
2881       && sym->is_from_dynobj())
2882     type = elfcpp::STT_FUNC;
2883   // A version script may have overridden the default binding.
2884   if (sym->is_forced_local())
2885     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2886   else
2887     osym.put_st_info(elfcpp::elf_st_info(binding, type));
2888   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2889   osym.put_st_shndx(shndx);
2890 }
2891
2892 // Check for unresolved symbols in shared libraries.  This is
2893 // controlled by the --allow-shlib-undefined option.
2894
2895 // We only warn about libraries for which we have seen all the
2896 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2897 // which were not seen in this link.  If we didn't see a DT_NEEDED
2898 // entry, we aren't going to be able to reliably report whether the
2899 // symbol is undefined.
2900
2901 // We also don't warn about libraries found in a system library
2902 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2903 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2904 // can have undefined references satisfied by ld-linux.so.
2905
2906 inline void
2907 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2908 {
2909   bool dummy;
2910   if (sym->source() == Symbol::FROM_OBJECT
2911       && sym->object()->is_dynamic()
2912       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2913       && sym->binding() != elfcpp::STB_WEAK
2914       && !parameters->options().allow_shlib_undefined()
2915       && !parameters->target().is_defined_by_abi(sym)
2916       && !sym->object()->is_in_system_directory())
2917     {
2918       // A very ugly cast.
2919       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2920       if (!dynobj->has_unknown_needed_entries())
2921         gold_undefined_symbol(sym);
2922     }
2923 }
2924
2925 // Write out a section symbol.  Return the update offset.
2926
2927 void
2928 Symbol_table::write_section_symbol(const Output_section *os,
2929                                    Output_symtab_xindex* symtab_xindex,
2930                                    Output_file* of,
2931                                    off_t offset) const
2932 {
2933   switch (parameters->size_and_endianness())
2934     {
2935 #ifdef HAVE_TARGET_32_LITTLE
2936     case Parameters::TARGET_32_LITTLE:
2937       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2938                                                   offset);
2939       break;
2940 #endif
2941 #ifdef HAVE_TARGET_32_BIG
2942     case Parameters::TARGET_32_BIG:
2943       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2944                                                  offset);
2945       break;
2946 #endif
2947 #ifdef HAVE_TARGET_64_LITTLE
2948     case Parameters::TARGET_64_LITTLE:
2949       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2950                                                   offset);
2951       break;
2952 #endif
2953 #ifdef HAVE_TARGET_64_BIG
2954     case Parameters::TARGET_64_BIG:
2955       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2956                                                  offset);
2957       break;
2958 #endif
2959     default:
2960       gold_unreachable();
2961     }
2962 }
2963
2964 // Write out a section symbol, specialized for size and endianness.
2965
2966 template<int size, bool big_endian>
2967 void
2968 Symbol_table::sized_write_section_symbol(const Output_section* os,
2969                                          Output_symtab_xindex* symtab_xindex,
2970                                          Output_file* of,
2971                                          off_t offset) const
2972 {
2973   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2974
2975   unsigned char* pov = of->get_output_view(offset, sym_size);
2976
2977   elfcpp::Sym_write<size, big_endian> osym(pov);
2978   osym.put_st_name(0);
2979   if (parameters->options().relocatable())
2980     osym.put_st_value(0);
2981   else
2982     osym.put_st_value(os->address());
2983   osym.put_st_size(0);
2984   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2985                                        elfcpp::STT_SECTION));
2986   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2987
2988   unsigned int shndx = os->out_shndx();
2989   if (shndx >= elfcpp::SHN_LORESERVE)
2990     {
2991       symtab_xindex->add(os->symtab_index(), shndx);
2992       shndx = elfcpp::SHN_XINDEX;
2993     }
2994   osym.put_st_shndx(shndx);
2995
2996   of->write_output_view(offset, sym_size, pov);
2997 }
2998
2999 // Print statistical information to stderr.  This is used for --stats.
3000
3001 void
3002 Symbol_table::print_stats() const
3003 {
3004 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
3005   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
3006           program_name, this->table_.size(), this->table_.bucket_count());
3007 #else
3008   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
3009           program_name, this->table_.size());
3010 #endif
3011   this->namepool_.print_stats("symbol table stringpool");
3012 }
3013
3014 // We check for ODR violations by looking for symbols with the same
3015 // name for which the debugging information reports that they were
3016 // defined in different source locations.  When comparing the source
3017 // location, we consider instances with the same base filename and
3018 // line number to be the same.  This is because different object
3019 // files/shared libraries can include the same header file using
3020 // different paths, and we don't want to report an ODR violation in
3021 // that case.
3022
3023 // This struct is used to compare line information, as returned by
3024 // Dwarf_line_info::one_addr2line.  It implements a < comparison
3025 // operator used with std::set.
3026
3027 struct Odr_violation_compare
3028 {
3029   bool
3030   operator()(const std::string& s1, const std::string& s2) const
3031   {
3032     std::string::size_type pos1 = s1.rfind('/');
3033     std::string::size_type pos2 = s2.rfind('/');
3034     if (pos1 == std::string::npos
3035         || pos2 == std::string::npos)
3036       return s1 < s2;
3037     return s1.compare(pos1, std::string::npos,
3038                       s2, pos2, std::string::npos) < 0;
3039   }
3040 };
3041
3042 // Check candidate_odr_violations_ to find symbols with the same name
3043 // but apparently different definitions (different source-file/line-no).
3044
3045 void
3046 Symbol_table::detect_odr_violations(const Task* task,
3047                                     const char* output_file_name) const
3048 {
3049   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3050        it != candidate_odr_violations_.end();
3051        ++it)
3052     {
3053       const char* symbol_name = it->first;
3054       // Maps from symbol location to a sample object file we found
3055       // that location in.  We use a sorted map so the location order
3056       // is deterministic, but we only store an arbitrary object file
3057       // to avoid copying lots of names.
3058       std::map<std::string, std::string, Odr_violation_compare> line_nums;
3059
3060       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3061                locs = it->second.begin();
3062            locs != it->second.end();
3063            ++locs)
3064         {
3065           // We need to lock the object in order to read it.  This
3066           // means that we have to run in a singleton Task.  If we
3067           // want to run this in a general Task for better
3068           // performance, we will need one Task for object, plus
3069           // appropriate locking to ensure that we don't conflict with
3070           // other uses of the object.  Also note, one_addr2line is not
3071           // currently thread-safe.
3072           Task_lock_obj<Object> tl(task, locs->object);
3073           // 16 is the size of the object-cache that one_addr2line should use.
3074           std::string lineno = Dwarf_line_info::one_addr2line(
3075               locs->object, locs->shndx, locs->offset, 16);
3076           if (!lineno.empty())
3077             {
3078               std::string& sample_object = line_nums[lineno];
3079               if (sample_object.empty())
3080                 sample_object = locs->object->name();
3081             }
3082         }
3083
3084       if (line_nums.size() > 1)
3085         {
3086           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3087                          "places (possible ODR violation):"),
3088                        output_file_name, demangle(symbol_name).c_str());
3089           for (std::map<std::string, std::string>::const_iterator it2 =
3090                  line_nums.begin();
3091                it2 != line_nums.end();
3092                ++it2)
3093             fprintf(stderr, _("  %s from %s\n"),
3094                     it2->first.c_str(), it2->second.c_str());
3095         }
3096     }
3097   // We only call one_addr2line() in this function, so we can clear its cache.
3098   Dwarf_line_info::clear_addr2line_cache();
3099 }
3100
3101 // Warnings functions.
3102
3103 // Add a new warning.
3104
3105 void
3106 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3107                       const std::string& warning)
3108 {
3109   name = symtab->canonicalize_name(name);
3110   this->warnings_[name].set(obj, warning);
3111 }
3112
3113 // Look through the warnings and mark the symbols for which we should
3114 // warn.  This is called during Layout::finalize when we know the
3115 // sources for all the symbols.
3116
3117 void
3118 Warnings::note_warnings(Symbol_table* symtab)
3119 {
3120   for (Warning_table::iterator p = this->warnings_.begin();
3121        p != this->warnings_.end();
3122        ++p)
3123     {
3124       Symbol* sym = symtab->lookup(p->first, NULL);
3125       if (sym != NULL
3126           && sym->source() == Symbol::FROM_OBJECT
3127           && sym->object() == p->second.object)
3128         sym->set_has_warning();
3129     }
3130 }
3131
3132 // Issue a warning.  This is called when we see a relocation against a
3133 // symbol for which has a warning.
3134
3135 template<int size, bool big_endian>
3136 void
3137 Warnings::issue_warning(const Symbol* sym,
3138                         const Relocate_info<size, big_endian>* relinfo,
3139                         size_t relnum, off_t reloffset) const
3140 {
3141   gold_assert(sym->has_warning());
3142   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3143   gold_assert(p != this->warnings_.end());
3144   gold_warning_at_location(relinfo, relnum, reloffset,
3145                            "%s", p->second.text.c_str());
3146 }
3147
3148 // Instantiate the templates we need.  We could use the configure
3149 // script to restrict this to only the ones needed for implemented
3150 // targets.
3151
3152 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3153 template
3154 void
3155 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3156 #endif
3157
3158 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3159 template
3160 void
3161 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3162 #endif
3163
3164 #ifdef HAVE_TARGET_32_LITTLE
3165 template
3166 void
3167 Symbol_table::add_from_relobj<32, false>(
3168     Sized_relobj<32, false>* relobj,
3169     const unsigned char* syms,
3170     size_t count,
3171     size_t symndx_offset,
3172     const char* sym_names,
3173     size_t sym_name_size,
3174     Sized_relobj<32, false>::Symbols* sympointers,
3175     size_t* defined);
3176 #endif
3177
3178 #ifdef HAVE_TARGET_32_BIG
3179 template
3180 void
3181 Symbol_table::add_from_relobj<32, true>(
3182     Sized_relobj<32, true>* 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, true>::Symbols* sympointers,
3189     size_t* defined);
3190 #endif
3191
3192 #ifdef HAVE_TARGET_64_LITTLE
3193 template
3194 void
3195 Symbol_table::add_from_relobj<64, false>(
3196     Sized_relobj<64, false>* 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<64, false>::Symbols* sympointers,
3203     size_t* defined);
3204 #endif
3205
3206 #ifdef HAVE_TARGET_64_BIG
3207 template
3208 void
3209 Symbol_table::add_from_relobj<64, true>(
3210     Sized_relobj<64, true>* 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, true>::Symbols* sympointers,
3217     size_t* defined);
3218 #endif
3219
3220 #ifdef HAVE_TARGET_32_LITTLE
3221 template
3222 Symbol*
3223 Symbol_table::add_from_pluginobj<32, false>(
3224     Sized_pluginobj<32, false>* obj,
3225     const char* name,
3226     const char* ver,
3227     elfcpp::Sym<32, false>* sym);
3228 #endif
3229
3230 #ifdef HAVE_TARGET_32_BIG
3231 template
3232 Symbol*
3233 Symbol_table::add_from_pluginobj<32, true>(
3234     Sized_pluginobj<32, true>* obj,
3235     const char* name,
3236     const char* ver,
3237     elfcpp::Sym<32, true>* sym);
3238 #endif
3239
3240 #ifdef HAVE_TARGET_64_LITTLE
3241 template
3242 Symbol*
3243 Symbol_table::add_from_pluginobj<64, false>(
3244     Sized_pluginobj<64, false>* obj,
3245     const char* name,
3246     const char* ver,
3247     elfcpp::Sym<64, false>* sym);
3248 #endif
3249
3250 #ifdef HAVE_TARGET_64_BIG
3251 template
3252 Symbol*
3253 Symbol_table::add_from_pluginobj<64, true>(
3254     Sized_pluginobj<64, true>* obj,
3255     const char* name,
3256     const char* ver,
3257     elfcpp::Sym<64, true>* sym);
3258 #endif
3259
3260 #ifdef HAVE_TARGET_32_LITTLE
3261 template
3262 void
3263 Symbol_table::add_from_dynobj<32, false>(
3264     Sized_dynobj<32, false>* dynobj,
3265     const unsigned char* syms,
3266     size_t count,
3267     const char* sym_names,
3268     size_t sym_name_size,
3269     const unsigned char* versym,
3270     size_t versym_size,
3271     const std::vector<const char*>* version_map,
3272     Sized_relobj<32, false>::Symbols* sympointers,
3273     size_t* defined);
3274 #endif
3275
3276 #ifdef HAVE_TARGET_32_BIG
3277 template
3278 void
3279 Symbol_table::add_from_dynobj<32, true>(
3280     Sized_dynobj<32, true>* dynobj,
3281     const unsigned char* syms,
3282     size_t count,
3283     const char* sym_names,
3284     size_t sym_name_size,
3285     const unsigned char* versym,
3286     size_t versym_size,
3287     const std::vector<const char*>* version_map,
3288     Sized_relobj<32, true>::Symbols* sympointers,
3289     size_t* defined);
3290 #endif
3291
3292 #ifdef HAVE_TARGET_64_LITTLE
3293 template
3294 void
3295 Symbol_table::add_from_dynobj<64, false>(
3296     Sized_dynobj<64, false>* dynobj,
3297     const unsigned char* syms,
3298     size_t count,
3299     const char* sym_names,
3300     size_t sym_name_size,
3301     const unsigned char* versym,
3302     size_t versym_size,
3303     const std::vector<const char*>* version_map,
3304     Sized_relobj<64, false>::Symbols* sympointers,
3305     size_t* defined);
3306 #endif
3307
3308 #ifdef HAVE_TARGET_64_BIG
3309 template
3310 void
3311 Symbol_table::add_from_dynobj<64, true>(
3312     Sized_dynobj<64, true>* dynobj,
3313     const unsigned char* syms,
3314     size_t count,
3315     const char* sym_names,
3316     size_t sym_name_size,
3317     const unsigned char* versym,
3318     size_t versym_size,
3319     const std::vector<const char*>* version_map,
3320     Sized_relobj<64, true>::Symbols* sympointers,
3321     size_t* defined);
3322 #endif
3323
3324 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3325 template
3326 void
3327 Symbol_table::define_with_copy_reloc<32>(
3328     Sized_symbol<32>* sym,
3329     Output_data* posd,
3330     elfcpp::Elf_types<32>::Elf_Addr value);
3331 #endif
3332
3333 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3334 template
3335 void
3336 Symbol_table::define_with_copy_reloc<64>(
3337     Sized_symbol<64>* sym,
3338     Output_data* posd,
3339     elfcpp::Elf_types<64>::Elf_Addr value);
3340 #endif
3341
3342 #ifdef HAVE_TARGET_32_LITTLE
3343 template
3344 void
3345 Warnings::issue_warning<32, false>(const Symbol* sym,
3346                                    const Relocate_info<32, false>* relinfo,
3347                                    size_t relnum, off_t reloffset) const;
3348 #endif
3349
3350 #ifdef HAVE_TARGET_32_BIG
3351 template
3352 void
3353 Warnings::issue_warning<32, true>(const Symbol* sym,
3354                                   const Relocate_info<32, true>* relinfo,
3355                                   size_t relnum, off_t reloffset) const;
3356 #endif
3357
3358 #ifdef HAVE_TARGET_64_LITTLE
3359 template
3360 void
3361 Warnings::issue_warning<64, false>(const Symbol* sym,
3362                                    const Relocate_info<64, false>* relinfo,
3363                                    size_t relnum, off_t reloffset) const;
3364 #endif
3365
3366 #ifdef HAVE_TARGET_64_BIG
3367 template
3368 void
3369 Warnings::issue_warning<64, true>(const Symbol* sym,
3370                                   const Relocate_info<64, true>* relinfo,
3371                                   size_t relnum, off_t reloffset) const;
3372 #endif
3373
3374 } // End namespace gold.