* resolve.cc (Symbol_table::resolve): Remember whether undef was
[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 "demangle.h"   // needed for --dynamic-list-cpp-new
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()
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
558 void
559 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
560 {
561   if (!sym->is_from_dynobj() 
562       && sym->is_externally_visible())
563     {
564       //Add the object and section to the work list.
565       Relobj* obj = static_cast<Relobj*>(sym->object());
566       bool is_ordinary;
567       unsigned int shndx = sym->shndx(&is_ordinary);
568       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
569         {
570           gold_assert(this->gc_!= NULL);
571           this->gc_->worklist().push(Section_id(obj, shndx));
572         }
573     }
574 }
575
576 // When doing garbage collection, keep symbols that have been seen in
577 // dynamic objects.
578 inline void 
579 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
580 {
581   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
582       && !sym->object()->is_dynamic())
583     {
584       Relobj *obj = static_cast<Relobj*>(sym->object()); 
585       bool is_ordinary;
586       unsigned int shndx = sym->shndx(&is_ordinary);
587       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
588         {
589           gold_assert(this->gc_ != NULL);
590           this->gc_->worklist().push(Section_id(obj, shndx));
591         }
592     }
593 }
594
595 // Make TO a symbol which forwards to FROM.
596
597 void
598 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
599 {
600   gold_assert(from != to);
601   gold_assert(!from->is_forwarder() && !to->is_forwarder());
602   this->forwarders_[from] = to;
603   from->set_forwarder();
604 }
605
606 // Resolve the forwards from FROM, returning the real symbol.
607
608 Symbol*
609 Symbol_table::resolve_forwards(const Symbol* from) const
610 {
611   gold_assert(from->is_forwarder());
612   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
613     this->forwarders_.find(from);
614   gold_assert(p != this->forwarders_.end());
615   return p->second;
616 }
617
618 // Look up a symbol by name.
619
620 Symbol*
621 Symbol_table::lookup(const char* name, const char* version) const
622 {
623   Stringpool::Key name_key;
624   name = this->namepool_.find(name, &name_key);
625   if (name == NULL)
626     return NULL;
627
628   Stringpool::Key version_key = 0;
629   if (version != NULL)
630     {
631       version = this->namepool_.find(version, &version_key);
632       if (version == NULL)
633         return NULL;
634     }
635
636   Symbol_table_key key(name_key, version_key);
637   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
638   if (p == this->table_.end())
639     return NULL;
640   return p->second;
641 }
642
643 // Resolve a Symbol with another Symbol.  This is only used in the
644 // unusual case where there are references to both an unversioned
645 // symbol and a symbol with a version, and we then discover that that
646 // version is the default version.  Because this is unusual, we do
647 // this the slow way, by converting back to an ELF symbol.
648
649 template<int size, bool big_endian>
650 void
651 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
652 {
653   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
654   elfcpp::Sym_write<size, big_endian> esym(buf);
655   // We don't bother to set the st_name or the st_shndx field.
656   esym.put_st_value(from->value());
657   esym.put_st_size(from->symsize());
658   esym.put_st_info(from->binding(), from->type());
659   esym.put_st_other(from->visibility(), from->nonvis());
660   bool is_ordinary;
661   unsigned int shndx = from->shndx(&is_ordinary);
662   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
663                 from->version());
664   if (from->in_reg())
665     to->set_in_reg();
666   if (from->in_dyn())
667     to->set_in_dyn();
668   if (parameters->options().gc_sections())
669     this->gc_mark_dyn_syms(to);
670 }
671
672 // Record that a symbol is forced to be local by a version script or
673 // by visibility.
674
675 void
676 Symbol_table::force_local(Symbol* sym)
677 {
678   if (!sym->is_defined() && !sym->is_common())
679     return;
680   if (sym->is_forced_local())
681     {
682       // We already got this one.
683       return;
684     }
685   sym->set_is_forced_local();
686   this->forced_locals_.push_back(sym);
687 }
688
689 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
690 // is only called for undefined symbols, when at least one --wrap
691 // option was used.
692
693 const char*
694 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
695 {
696   // For some targets, we need to ignore a specific character when
697   // wrapping, and add it back later.
698   char prefix = '\0';
699   if (name[0] == parameters->target().wrap_char())
700     {
701       prefix = name[0];
702       ++name;
703     }
704
705   if (parameters->options().is_wrap(name))
706     {
707       // Turn NAME into __wrap_NAME.
708       std::string s;
709       if (prefix != '\0')
710         s += prefix;
711       s += "__wrap_";
712       s += name;
713
714       // This will give us both the old and new name in NAMEPOOL_, but
715       // that is OK.  Only the versions we need will wind up in the
716       // real string table in the output file.
717       return this->namepool_.add(s.c_str(), true, name_key);
718     }
719
720   const char* const real_prefix = "__real_";
721   const size_t real_prefix_length = strlen(real_prefix);
722   if (strncmp(name, real_prefix, real_prefix_length) == 0
723       && parameters->options().is_wrap(name + real_prefix_length))
724     {
725       // Turn __real_NAME into NAME.
726       std::string s;
727       if (prefix != '\0')
728         s += prefix;
729       s += name + real_prefix_length;
730       return this->namepool_.add(s.c_str(), true, name_key);
731     }
732
733   return name;
734 }
735
736 // This is called when we see a symbol NAME/VERSION, and the symbol
737 // already exists in the symbol table, and VERSION is marked as being
738 // the default version.  SYM is the NAME/VERSION symbol we just added.
739 // DEFAULT_IS_NEW is true if this is the first time we have seen the
740 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
741
742 template<int size, bool big_endian>
743 void
744 Symbol_table::define_default_version(Sized_symbol<size>* sym,
745                                      bool default_is_new,
746                                      Symbol_table_type::iterator pdef)
747 {
748   if (default_is_new)
749     {
750       // This is the first time we have seen NAME/NULL.  Make
751       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
752       // version.
753       pdef->second = sym;
754       sym->set_is_default();
755     }
756   else if (pdef->second == sym)
757     {
758       // NAME/NULL already points to NAME/VERSION.  Don't mark the
759       // symbol as the default if it is not already the default.
760     }
761   else
762     {
763       // This is the unfortunate case where we already have entries
764       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
765       // NAME/VERSION where VERSION is the default version.  We have
766       // already resolved this new symbol with the existing
767       // NAME/VERSION symbol.
768
769       // It's possible that NAME/NULL and NAME/VERSION are both
770       // defined in regular objects.  This can only happen if one
771       // object file defines foo and another defines foo@@ver.  This
772       // is somewhat obscure, but we call it a multiple definition
773       // error.
774
775       // It's possible that NAME/NULL actually has a version, in which
776       // case it won't be the same as VERSION.  This happens with
777       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
778       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
779       // then see an unadorned t2_2 in an object file and give it
780       // version VER1 from the version script.  This looks like a
781       // default definition for VER1, so it looks like we should merge
782       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
783       // not obvious that this is an error, either.  So we just punt.
784
785       // If one of the symbols has non-default visibility, and the
786       // other is defined in a shared object, then they are different
787       // symbols.
788
789       // Otherwise, we just resolve the symbols as though they were
790       // the same.
791
792       if (pdef->second->version() != NULL)
793         gold_assert(pdef->second->version() != sym->version());
794       else if (sym->visibility() != elfcpp::STV_DEFAULT
795                && pdef->second->is_from_dynobj())
796         ;
797       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
798                && sym->is_from_dynobj())
799         ;
800       else
801         {
802           const Sized_symbol<size>* symdef;
803           symdef = this->get_sized_symbol<size>(pdef->second);
804           Symbol_table::resolve<size, big_endian>(sym, symdef);
805           this->make_forwarder(pdef->second, sym);
806           pdef->second = sym;
807           sym->set_is_default();
808         }
809     }
810 }
811
812 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
813 // name and VERSION is the version; both are canonicalized.  DEF is
814 // whether this is the default version.  ST_SHNDX is the symbol's
815 // section index; IS_ORDINARY is whether this is a normal section
816 // rather than a special code.
817
818 // If IS_DEFAULT_VERSION is true, then this is the definition of a
819 // default version of a symbol.  That means that any lookup of
820 // NAME/NULL and any lookup of NAME/VERSION should always return the
821 // same symbol.  This is obvious for references, but in particular we
822 // want to do this for definitions: overriding NAME/NULL should also
823 // override NAME/VERSION.  If we don't do that, it would be very hard
824 // to override functions in a shared library which uses versioning.
825
826 // We implement this by simply making both entries in the hash table
827 // point to the same Symbol structure.  That is easy enough if this is
828 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
829 // that we have seen both already, in which case they will both have
830 // independent entries in the symbol table.  We can't simply change
831 // the symbol table entry, because we have pointers to the entries
832 // attached to the object files.  So we mark the entry attached to the
833 // object file as a forwarder, and record it in the forwarders_ map.
834 // Note that entries in the hash table will never be marked as
835 // forwarders.
836 //
837 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
838 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
839 // for a special section code.  ST_SHNDX may be modified if the symbol
840 // is defined in a section being discarded.
841
842 template<int size, bool big_endian>
843 Sized_symbol<size>*
844 Symbol_table::add_from_object(Object* object,
845                               const char *name,
846                               Stringpool::Key name_key,
847                               const char *version,
848                               Stringpool::Key version_key,
849                               bool is_default_version,
850                               const elfcpp::Sym<size, big_endian>& sym,
851                               unsigned int st_shndx,
852                               bool is_ordinary,
853                               unsigned int orig_st_shndx)
854 {
855   // Print a message if this symbol is being traced.
856   if (parameters->options().is_trace_symbol(name))
857     {
858       if (orig_st_shndx == elfcpp::SHN_UNDEF)
859         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
860       else
861         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
862     }
863
864   // For an undefined symbol, we may need to adjust the name using
865   // --wrap.
866   if (orig_st_shndx == elfcpp::SHN_UNDEF
867       && parameters->options().any_wrap())
868     {
869       const char* wrap_name = this->wrap_symbol(name, &name_key);
870       if (wrap_name != name)
871         {
872           // If we see a reference to malloc with version GLIBC_2.0,
873           // and we turn it into a reference to __wrap_malloc, then we
874           // discard the version number.  Otherwise the user would be
875           // required to specify the correct version for
876           // __wrap_malloc.
877           version = NULL;
878           version_key = 0;
879           name = wrap_name;
880         }
881     }
882
883   Symbol* const snull = NULL;
884   std::pair<typename Symbol_table_type::iterator, bool> ins =
885     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
886                                        snull));
887
888   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
889     std::make_pair(this->table_.end(), false);
890   if (is_default_version)
891     {
892       const Stringpool::Key vnull_key = 0;
893       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
894                                                                      vnull_key),
895                                                       snull));
896     }
897
898   // ins.first: an iterator, which is a pointer to a pair.
899   // ins.first->first: the key (a pair of name and version).
900   // ins.first->second: the value (Symbol*).
901   // ins.second: true if new entry was inserted, false if not.
902
903   Sized_symbol<size>* ret;
904   bool was_undefined;
905   bool was_common;
906   if (!ins.second)
907     {
908       // We already have an entry for NAME/VERSION.
909       ret = this->get_sized_symbol<size>(ins.first->second);
910       gold_assert(ret != NULL);
911
912       was_undefined = ret->is_undefined();
913       was_common = ret->is_common();
914
915       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
916                     version);
917       if (parameters->options().gc_sections())
918         this->gc_mark_dyn_syms(ret);
919
920       if (is_default_version)
921         this->define_default_version<size, big_endian>(ret, insdefault.second,
922                                                        insdefault.first);
923     }
924   else
925     {
926       // This is the first time we have seen NAME/VERSION.
927       gold_assert(ins.first->second == NULL);
928
929       if (is_default_version && !insdefault.second)
930         {
931           // We already have an entry for NAME/NULL.  If we override
932           // it, then change it to NAME/VERSION.
933           ret = this->get_sized_symbol<size>(insdefault.first->second);
934
935           was_undefined = ret->is_undefined();
936           was_common = ret->is_common();
937
938           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
939                         version);
940           if (parameters->options().gc_sections())
941             this->gc_mark_dyn_syms(ret);
942           ins.first->second = ret;
943         }
944       else
945         {
946           was_undefined = false;
947           was_common = false;
948
949           Sized_target<size, big_endian>* target =
950             parameters->sized_target<size, big_endian>();
951           if (!target->has_make_symbol())
952             ret = new Sized_symbol<size>();
953           else
954             {
955               ret = target->make_symbol();
956               if (ret == NULL)
957                 {
958                   // This means that we don't want a symbol table
959                   // entry after all.
960                   if (!is_default_version)
961                     this->table_.erase(ins.first);
962                   else
963                     {
964                       this->table_.erase(insdefault.first);
965                       // Inserting INSDEFAULT invalidated INS.
966                       this->table_.erase(std::make_pair(name_key,
967                                                         version_key));
968                     }
969                   return NULL;
970                 }
971             }
972
973           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
974
975           ins.first->second = ret;
976           if (is_default_version)
977             {
978               // This is the first time we have seen NAME/NULL.  Point
979               // it at the new entry for NAME/VERSION.
980               gold_assert(insdefault.second);
981               insdefault.first->second = ret;
982             }
983         }
984
985       if (is_default_version)
986         ret->set_is_default();
987     }
988
989   // Record every time we see a new undefined symbol, to speed up
990   // archive groups.
991   if (!was_undefined && ret->is_undefined())
992     ++this->saw_undefined_;
993
994   // Keep track of common symbols, to speed up common symbol
995   // allocation.
996   if (!was_common && ret->is_common())
997     {
998       if (ret->type() == elfcpp::STT_TLS)
999         this->tls_commons_.push_back(ret);
1000       else if (!is_ordinary
1001                && st_shndx == parameters->target().small_common_shndx())
1002         this->small_commons_.push_back(ret);
1003       else if (!is_ordinary
1004                && st_shndx == parameters->target().large_common_shndx())
1005         this->large_commons_.push_back(ret);
1006       else
1007         this->commons_.push_back(ret);
1008     }
1009
1010   // If we're not doing a relocatable link, then any symbol with
1011   // hidden or internal visibility is local.
1012   if ((ret->visibility() == elfcpp::STV_HIDDEN
1013        || ret->visibility() == elfcpp::STV_INTERNAL)
1014       && (ret->binding() == elfcpp::STB_GLOBAL
1015           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1016           || ret->binding() == elfcpp::STB_WEAK)
1017       && !parameters->options().relocatable())
1018     this->force_local(ret);
1019
1020   return ret;
1021 }
1022
1023 // Add all the symbols in a relocatable object to the hash table.
1024
1025 template<int size, bool big_endian>
1026 void
1027 Symbol_table::add_from_relobj(
1028     Sized_relobj<size, big_endian>* relobj,
1029     const unsigned char* syms,
1030     size_t count,
1031     size_t symndx_offset,
1032     const char* sym_names,
1033     size_t sym_name_size,
1034     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1035     size_t *defined)
1036 {
1037   *defined = 0;
1038
1039   gold_assert(size == parameters->target().get_size());
1040
1041   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1042
1043   const bool just_symbols = relobj->just_symbols();
1044
1045   const unsigned char* p = syms;
1046   for (size_t i = 0; i < count; ++i, p += sym_size)
1047     {
1048       (*sympointers)[i] = NULL;
1049
1050       elfcpp::Sym<size, big_endian> sym(p);
1051
1052       unsigned int st_name = sym.get_st_name();
1053       if (st_name >= sym_name_size)
1054         {
1055           relobj->error(_("bad global symbol name offset %u at %zu"),
1056                         st_name, i);
1057           continue;
1058         }
1059
1060       const char* name = sym_names + st_name;
1061
1062       bool is_ordinary;
1063       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1064                                                        sym.get_st_shndx(),
1065                                                        &is_ordinary);
1066       unsigned int orig_st_shndx = st_shndx;
1067       if (!is_ordinary)
1068         orig_st_shndx = elfcpp::SHN_UNDEF;
1069
1070       if (st_shndx != elfcpp::SHN_UNDEF)
1071         ++*defined;
1072
1073       // A symbol defined in a section which we are not including must
1074       // be treated as an undefined symbol.
1075       bool is_defined_in_discarded_section = false;
1076       if (st_shndx != elfcpp::SHN_UNDEF
1077           && is_ordinary
1078           && !relobj->is_section_included(st_shndx)
1079           && !this->is_section_folded(relobj, st_shndx))
1080         {
1081           st_shndx = elfcpp::SHN_UNDEF;
1082           is_defined_in_discarded_section = true;
1083         }
1084
1085       // In an object file, an '@' in the name separates the symbol
1086       // name from the version name.  If there are two '@' characters,
1087       // this is the default version.
1088       const char* ver = strchr(name, '@');
1089       Stringpool::Key ver_key = 0;
1090       int namelen = 0;
1091       // IS_DEFAULT_VERSION: is the version default?
1092       // IS_FORCED_LOCAL: is the symbol forced local?
1093       bool is_default_version = false;
1094       bool is_forced_local = false;
1095
1096       if (ver != NULL)
1097         {
1098           // The symbol name is of the form foo@VERSION or foo@@VERSION
1099           namelen = ver - name;
1100           ++ver;
1101           if (*ver == '@')
1102             {
1103               is_default_version = true;
1104               ++ver;
1105             }
1106           ver = this->namepool_.add(ver, true, &ver_key);
1107         }
1108       // We don't want to assign a version to an undefined symbol,
1109       // even if it is listed in the version script.  FIXME: What
1110       // about a common symbol?
1111       else
1112         {
1113           namelen = strlen(name);
1114           if (!this->version_script_.empty()
1115               && st_shndx != elfcpp::SHN_UNDEF)
1116             {
1117               // The symbol name did not have a version, but the
1118               // version script may assign a version anyway.
1119               std::string version;
1120               bool is_global;
1121               if (this->version_script_.get_symbol_version(name, &version,
1122                                                            &is_global))
1123                 {
1124                   if (!is_global)
1125                     is_forced_local = true;
1126                   else if (!version.empty())
1127                     {
1128                       ver = this->namepool_.add_with_length(version.c_str(),
1129                                                             version.length(),
1130                                                             true,
1131                                                             &ver_key);
1132                       is_default_version = true;
1133                     }
1134                 }
1135             }
1136         }
1137
1138       elfcpp::Sym<size, big_endian>* psym = &sym;
1139       unsigned char symbuf[sym_size];
1140       elfcpp::Sym<size, big_endian> sym2(symbuf);
1141       if (just_symbols)
1142         {
1143           memcpy(symbuf, p, sym_size);
1144           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1145           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1146             {
1147               // Symbol values in object files are section relative.
1148               // This is normally what we want, but since here we are
1149               // converting the symbol to absolute we need to add the
1150               // section address.  The section address in an object
1151               // file is normally zero, but people can use a linker
1152               // script to change it.
1153               sw.put_st_value(sym.get_st_value()
1154                               + relobj->section_address(orig_st_shndx));
1155             }
1156           st_shndx = elfcpp::SHN_ABS;
1157           is_ordinary = false;
1158           psym = &sym2;
1159         }
1160
1161       // Fix up visibility if object has no-export set.
1162       if (relobj->no_export()
1163           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1164         {
1165           // We may have copied symbol already above.
1166           if (psym != &sym2)
1167             {
1168               memcpy(symbuf, p, sym_size);
1169               psym = &sym2;
1170             }
1171
1172           elfcpp::STV visibility = sym2.get_st_visibility();
1173           if (visibility == elfcpp::STV_DEFAULT
1174               || visibility == elfcpp::STV_PROTECTED)
1175             {
1176               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1177               unsigned char nonvis = sym2.get_st_nonvis();
1178               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1179             }
1180         }
1181
1182       Stringpool::Key name_key;
1183       name = this->namepool_.add_with_length(name, namelen, true,
1184                                              &name_key);
1185
1186       Sized_symbol<size>* res;
1187       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1188                                   is_default_version, *psym, st_shndx,
1189                                   is_ordinary, orig_st_shndx);
1190       
1191       // If building a shared library using garbage collection, do not 
1192       // treat externally visible symbols as garbage.
1193       if (parameters->options().gc_sections() 
1194           && parameters->options().shared())
1195         this->gc_mark_symbol_for_shlib(res);
1196
1197       if (is_forced_local)
1198         this->force_local(res);
1199
1200       if (is_defined_in_discarded_section)
1201         res->set_is_defined_in_discarded_section();
1202
1203       (*sympointers)[i] = res;
1204     }
1205 }
1206
1207 // Add a symbol from a plugin-claimed file.
1208
1209 template<int size, bool big_endian>
1210 Symbol*
1211 Symbol_table::add_from_pluginobj(
1212     Sized_pluginobj<size, big_endian>* obj,
1213     const char* name,
1214     const char* ver,
1215     elfcpp::Sym<size, big_endian>* sym)
1216 {
1217   unsigned int st_shndx = sym->get_st_shndx();
1218   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1219
1220   Stringpool::Key ver_key = 0;
1221   bool is_default_version = false;
1222   bool is_forced_local = false;
1223
1224   if (ver != NULL)
1225     {
1226       ver = this->namepool_.add(ver, true, &ver_key);
1227     }
1228   // We don't want to assign a version to an undefined symbol,
1229   // even if it is listed in the version script.  FIXME: What
1230   // about a common symbol?
1231   else
1232     {
1233       if (!this->version_script_.empty()
1234           && st_shndx != elfcpp::SHN_UNDEF)
1235         {
1236           // The symbol name did not have a version, but the
1237           // version script may assign a version anyway.
1238           std::string version;
1239           bool is_global;
1240           if (this->version_script_.get_symbol_version(name, &version,
1241                                                        &is_global))
1242             {
1243               if (!is_global)
1244                 is_forced_local = true;
1245               else if (!version.empty())
1246                 {
1247                   ver = this->namepool_.add_with_length(version.c_str(),
1248                                                         version.length(),
1249                                                         true,
1250                                                         &ver_key);
1251                   is_default_version = true;
1252                 }
1253             }
1254         }
1255     }
1256
1257   Stringpool::Key name_key;
1258   name = this->namepool_.add(name, true, &name_key);
1259
1260   Sized_symbol<size>* res;
1261   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1262                               is_default_version, *sym, st_shndx,
1263                               is_ordinary, st_shndx);
1264
1265   if (is_forced_local)
1266     this->force_local(res);
1267
1268   return res;
1269 }
1270
1271 // Add all the symbols in a dynamic object to the hash table.
1272
1273 template<int size, bool big_endian>
1274 void
1275 Symbol_table::add_from_dynobj(
1276     Sized_dynobj<size, big_endian>* dynobj,
1277     const unsigned char* syms,
1278     size_t count,
1279     const char* sym_names,
1280     size_t sym_name_size,
1281     const unsigned char* versym,
1282     size_t versym_size,
1283     const std::vector<const char*>* version_map,
1284     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1285     size_t* defined)
1286 {
1287   *defined = 0;
1288
1289   gold_assert(size == parameters->target().get_size());
1290
1291   if (dynobj->just_symbols())
1292     {
1293       gold_error(_("--just-symbols does not make sense with a shared object"));
1294       return;
1295     }
1296
1297   if (versym != NULL && versym_size / 2 < count)
1298     {
1299       dynobj->error(_("too few symbol versions"));
1300       return;
1301     }
1302
1303   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1304
1305   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1306   // weak aliases.  This is necessary because if the dynamic object
1307   // provides the same variable under two names, one of which is a
1308   // weak definition, and the regular object refers to the weak
1309   // definition, we have to put both the weak definition and the
1310   // strong definition into the dynamic symbol table.  Given a weak
1311   // definition, the only way that we can find the corresponding
1312   // strong definition, if any, is to search the symbol table.
1313   std::vector<Sized_symbol<size>*> object_symbols;
1314
1315   const unsigned char* p = syms;
1316   const unsigned char* vs = versym;
1317   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1318     {
1319       elfcpp::Sym<size, big_endian> sym(p);
1320
1321       if (sympointers != NULL)
1322         (*sympointers)[i] = NULL;
1323
1324       // Ignore symbols with local binding or that have
1325       // internal or hidden visibility.
1326       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1327           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1328           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1329         continue;
1330
1331       // A protected symbol in a shared library must be treated as a
1332       // normal symbol when viewed from outside the shared library.
1333       // Implement this by overriding the visibility here.
1334       elfcpp::Sym<size, big_endian>* psym = &sym;
1335       unsigned char symbuf[sym_size];
1336       elfcpp::Sym<size, big_endian> sym2(symbuf);
1337       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1338         {
1339           memcpy(symbuf, p, sym_size);
1340           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1341           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1342           psym = &sym2;
1343         }
1344
1345       unsigned int st_name = psym->get_st_name();
1346       if (st_name >= sym_name_size)
1347         {
1348           dynobj->error(_("bad symbol name offset %u at %zu"),
1349                         st_name, i);
1350           continue;
1351         }
1352
1353       const char* name = sym_names + st_name;
1354
1355       bool is_ordinary;
1356       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1357                                                        &is_ordinary);
1358
1359       if (st_shndx != elfcpp::SHN_UNDEF)
1360         ++*defined;
1361
1362       Sized_symbol<size>* res;
1363
1364       if (versym == NULL)
1365         {
1366           Stringpool::Key name_key;
1367           name = this->namepool_.add(name, true, &name_key);
1368           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1369                                       false, *psym, st_shndx, is_ordinary,
1370                                       st_shndx);
1371         }
1372       else
1373         {
1374           // Read the version information.
1375
1376           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1377
1378           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1379           v &= elfcpp::VERSYM_VERSION;
1380
1381           // The Sun documentation says that V can be VER_NDX_LOCAL,
1382           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1383           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1384           // The old GNU linker will happily generate VER_NDX_LOCAL
1385           // for an undefined symbol.  I don't know what the Sun
1386           // linker will generate.
1387
1388           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1389               && st_shndx != elfcpp::SHN_UNDEF)
1390             {
1391               // This symbol should not be visible outside the object.
1392               continue;
1393             }
1394
1395           // At this point we are definitely going to add this symbol.
1396           Stringpool::Key name_key;
1397           name = this->namepool_.add(name, true, &name_key);
1398
1399           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1400               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1401             {
1402               // This symbol does not have a version.
1403               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1404                                           false, *psym, st_shndx, is_ordinary,
1405                                           st_shndx);
1406             }
1407           else
1408             {
1409               if (v >= version_map->size())
1410                 {
1411                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1412                                 i, v);
1413                   continue;
1414                 }
1415
1416               const char* version = (*version_map)[v];
1417               if (version == NULL)
1418                 {
1419                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1420                                 i, v);
1421                   continue;
1422                 }
1423
1424               Stringpool::Key version_key;
1425               version = this->namepool_.add(version, true, &version_key);
1426
1427               // If this is an absolute symbol, and the version name
1428               // and symbol name are the same, then this is the
1429               // version definition symbol.  These symbols exist to
1430               // support using -u to pull in particular versions.  We
1431               // do not want to record a version for them.
1432               if (st_shndx == elfcpp::SHN_ABS
1433                   && !is_ordinary
1434                   && name_key == version_key)
1435                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1436                                             false, *psym, st_shndx, is_ordinary,
1437                                             st_shndx);
1438               else
1439                 {
1440                   const bool is_default_version =
1441                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1442                   res = this->add_from_object(dynobj, name, name_key, version,
1443                                               version_key, is_default_version,
1444                                               *psym, st_shndx,
1445                                               is_ordinary, st_shndx);
1446                 }
1447             }
1448         }
1449
1450       // Note that it is possible that RES was overridden by an
1451       // earlier object, in which case it can't be aliased here.
1452       if (st_shndx != elfcpp::SHN_UNDEF
1453           && is_ordinary
1454           && psym->get_st_type() == elfcpp::STT_OBJECT
1455           && res->source() == Symbol::FROM_OBJECT
1456           && res->object() == dynobj)
1457         object_symbols.push_back(res);
1458
1459       if (sympointers != NULL)
1460         (*sympointers)[i] = res;
1461     }
1462
1463   this->record_weak_aliases(&object_symbols);
1464 }
1465
1466 // This is used to sort weak aliases.  We sort them first by section
1467 // index, then by offset, then by weak ahead of strong.
1468
1469 template<int size>
1470 class Weak_alias_sorter
1471 {
1472  public:
1473   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1474 };
1475
1476 template<int size>
1477 bool
1478 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1479                                     const Sized_symbol<size>* s2) const
1480 {
1481   bool is_ordinary;
1482   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1483   gold_assert(is_ordinary);
1484   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1485   gold_assert(is_ordinary);
1486   if (s1_shndx != s2_shndx)
1487     return s1_shndx < s2_shndx;
1488
1489   if (s1->value() != s2->value())
1490     return s1->value() < s2->value();
1491   if (s1->binding() != s2->binding())
1492     {
1493       if (s1->binding() == elfcpp::STB_WEAK)
1494         return true;
1495       if (s2->binding() == elfcpp::STB_WEAK)
1496         return false;
1497     }
1498   return std::string(s1->name()) < std::string(s2->name());
1499 }
1500
1501 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1502 // for any weak aliases, and record them so that if we add the weak
1503 // alias to the dynamic symbol table, we also add the corresponding
1504 // strong symbol.
1505
1506 template<int size>
1507 void
1508 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1509 {
1510   // Sort the vector by section index, then by offset, then by weak
1511   // ahead of strong.
1512   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1513
1514   // Walk through the vector.  For each weak definition, record
1515   // aliases.
1516   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1517          symbols->begin();
1518        p != symbols->end();
1519        ++p)
1520     {
1521       if ((*p)->binding() != elfcpp::STB_WEAK)
1522         continue;
1523
1524       // Build a circular list of weak aliases.  Each symbol points to
1525       // the next one in the circular list.
1526
1527       Sized_symbol<size>* from_sym = *p;
1528       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1529       for (q = p + 1; q != symbols->end(); ++q)
1530         {
1531           bool dummy;
1532           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1533               || (*q)->value() != from_sym->value())
1534             break;
1535
1536           this->weak_aliases_[from_sym] = *q;
1537           from_sym->set_has_alias();
1538           from_sym = *q;
1539         }
1540
1541       if (from_sym != *p)
1542         {
1543           this->weak_aliases_[from_sym] = *p;
1544           from_sym->set_has_alias();
1545         }
1546
1547       p = q - 1;
1548     }
1549 }
1550
1551 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1552 // true, then only create the symbol if there is a reference to it.
1553 // If this does not return NULL, it sets *POLDSYM to the existing
1554 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1555 // resolve the newly created symbol to the old one.  This
1556 // canonicalizes *PNAME and *PVERSION.
1557
1558 template<int size, bool big_endian>
1559 Sized_symbol<size>*
1560 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1561                                     bool only_if_ref,
1562                                     Sized_symbol<size>** poldsym,
1563                                     bool *resolve_oldsym)
1564 {
1565   *resolve_oldsym = false;
1566
1567   // If the caller didn't give us a version, see if we get one from
1568   // the version script.
1569   std::string v;
1570   bool is_default_version = false;
1571   if (*pversion == NULL)
1572     {
1573       bool is_global;
1574       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1575         {
1576           if (is_global && !v.empty())
1577             {
1578               *pversion = v.c_str();
1579               // If we get the version from a version script, then we
1580               // are also the default version.
1581               is_default_version = true;
1582             }
1583         }
1584     }
1585
1586   Symbol* oldsym;
1587   Sized_symbol<size>* sym;
1588
1589   bool add_to_table = false;
1590   typename Symbol_table_type::iterator add_loc = this->table_.end();
1591   bool add_def_to_table = false;
1592   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1593
1594   if (only_if_ref)
1595     {
1596       oldsym = this->lookup(*pname, *pversion);
1597       if (oldsym == NULL && is_default_version)
1598         oldsym = this->lookup(*pname, NULL);
1599       if (oldsym == NULL || !oldsym->is_undefined())
1600         return NULL;
1601
1602       *pname = oldsym->name();
1603       if (!is_default_version)
1604         *pversion = oldsym->version();
1605     }
1606   else
1607     {
1608       // Canonicalize NAME and VERSION.
1609       Stringpool::Key name_key;
1610       *pname = this->namepool_.add(*pname, true, &name_key);
1611
1612       Stringpool::Key version_key = 0;
1613       if (*pversion != NULL)
1614         *pversion = this->namepool_.add(*pversion, true, &version_key);
1615
1616       Symbol* const snull = NULL;
1617       std::pair<typename Symbol_table_type::iterator, bool> ins =
1618         this->table_.insert(std::make_pair(std::make_pair(name_key,
1619                                                           version_key),
1620                                            snull));
1621
1622       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1623         std::make_pair(this->table_.end(), false);
1624       if (is_default_version)
1625         {
1626           const Stringpool::Key vnull = 0;
1627           insdefault =
1628             this->table_.insert(std::make_pair(std::make_pair(name_key,
1629                                                               vnull),
1630                                                snull));
1631         }
1632
1633       if (!ins.second)
1634         {
1635           // We already have a symbol table entry for NAME/VERSION.
1636           oldsym = ins.first->second;
1637           gold_assert(oldsym != NULL);
1638
1639           if (is_default_version)
1640             {
1641               Sized_symbol<size>* soldsym =
1642                 this->get_sized_symbol<size>(oldsym);
1643               this->define_default_version<size, big_endian>(soldsym,
1644                                                              insdefault.second,
1645                                                              insdefault.first);
1646             }
1647         }
1648       else
1649         {
1650           // We haven't seen this symbol before.
1651           gold_assert(ins.first->second == NULL);
1652
1653           add_to_table = true;
1654           add_loc = ins.first;
1655
1656           if (is_default_version && !insdefault.second)
1657             {
1658               // We are adding NAME/VERSION, and it is the default
1659               // version.  We already have an entry for NAME/NULL.
1660               oldsym = insdefault.first->second;
1661               *resolve_oldsym = true;
1662             }
1663           else
1664             {
1665               oldsym = NULL;
1666
1667               if (is_default_version)
1668                 {
1669                   add_def_to_table = true;
1670                   add_def_loc = insdefault.first;
1671                 }
1672             }
1673         }
1674     }
1675
1676   const Target& target = parameters->target();
1677   if (!target.has_make_symbol())
1678     sym = new Sized_symbol<size>();
1679   else
1680     {
1681       Sized_target<size, big_endian>* sized_target =
1682         parameters->sized_target<size, big_endian>();
1683       sym = sized_target->make_symbol();
1684       if (sym == NULL)
1685         return NULL;
1686     }
1687
1688   if (add_to_table)
1689     add_loc->second = sym;
1690   else
1691     gold_assert(oldsym != NULL);
1692
1693   if (add_def_to_table)
1694     add_def_loc->second = sym;
1695
1696   *poldsym = this->get_sized_symbol<size>(oldsym);
1697
1698   return sym;
1699 }
1700
1701 // Define a symbol based on an Output_data.
1702
1703 Symbol*
1704 Symbol_table::define_in_output_data(const char* name,
1705                                     const char* version,
1706                                     Defined defined,
1707                                     Output_data* od,
1708                                     uint64_t value,
1709                                     uint64_t symsize,
1710                                     elfcpp::STT type,
1711                                     elfcpp::STB binding,
1712                                     elfcpp::STV visibility,
1713                                     unsigned char nonvis,
1714                                     bool offset_is_from_end,
1715                                     bool only_if_ref)
1716 {
1717   if (parameters->target().get_size() == 32)
1718     {
1719 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1720       return this->do_define_in_output_data<32>(name, version, defined, od,
1721                                                 value, symsize, type, binding,
1722                                                 visibility, nonvis,
1723                                                 offset_is_from_end,
1724                                                 only_if_ref);
1725 #else
1726       gold_unreachable();
1727 #endif
1728     }
1729   else if (parameters->target().get_size() == 64)
1730     {
1731 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1732       return this->do_define_in_output_data<64>(name, version, defined, od,
1733                                                 value, symsize, type, binding,
1734                                                 visibility, nonvis,
1735                                                 offset_is_from_end,
1736                                                 only_if_ref);
1737 #else
1738       gold_unreachable();
1739 #endif
1740     }
1741   else
1742     gold_unreachable();
1743 }
1744
1745 // Define a symbol in an Output_data, sized version.
1746
1747 template<int size>
1748 Sized_symbol<size>*
1749 Symbol_table::do_define_in_output_data(
1750     const char* name,
1751     const char* version,
1752     Defined defined,
1753     Output_data* od,
1754     typename elfcpp::Elf_types<size>::Elf_Addr value,
1755     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1756     elfcpp::STT type,
1757     elfcpp::STB binding,
1758     elfcpp::STV visibility,
1759     unsigned char nonvis,
1760     bool offset_is_from_end,
1761     bool only_if_ref)
1762 {
1763   Sized_symbol<size>* sym;
1764   Sized_symbol<size>* oldsym;
1765   bool resolve_oldsym;
1766
1767   if (parameters->target().is_big_endian())
1768     {
1769 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1770       sym = this->define_special_symbol<size, true>(&name, &version,
1771                                                     only_if_ref, &oldsym,
1772                                                     &resolve_oldsym);
1773 #else
1774       gold_unreachable();
1775 #endif
1776     }
1777   else
1778     {
1779 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1780       sym = this->define_special_symbol<size, false>(&name, &version,
1781                                                      only_if_ref, &oldsym,
1782                                                      &resolve_oldsym);
1783 #else
1784       gold_unreachable();
1785 #endif
1786     }
1787
1788   if (sym == NULL)
1789     return NULL;
1790
1791   sym->init_output_data(name, version, od, value, symsize, type, binding,
1792                         visibility, nonvis, offset_is_from_end);
1793
1794   if (oldsym == NULL)
1795     {
1796       if (binding == elfcpp::STB_LOCAL
1797           || this->version_script_.symbol_is_local(name))
1798         this->force_local(sym);
1799       else if (version != NULL)
1800         sym->set_is_default();
1801       return sym;
1802     }
1803
1804   if (Symbol_table::should_override_with_special(oldsym, defined))
1805     this->override_with_special(oldsym, sym);
1806
1807   if (resolve_oldsym)
1808     return sym;
1809   else
1810     {
1811       delete sym;
1812       return oldsym;
1813     }
1814 }
1815
1816 // Define a symbol based on an Output_segment.
1817
1818 Symbol*
1819 Symbol_table::define_in_output_segment(const char* name,
1820                                        const char* version,
1821                                        Defined defined,
1822                                        Output_segment* os,
1823                                        uint64_t value,
1824                                        uint64_t symsize,
1825                                        elfcpp::STT type,
1826                                        elfcpp::STB binding,
1827                                        elfcpp::STV visibility,
1828                                        unsigned char nonvis,
1829                                        Symbol::Segment_offset_base offset_base,
1830                                        bool only_if_ref)
1831 {
1832   if (parameters->target().get_size() == 32)
1833     {
1834 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1835       return this->do_define_in_output_segment<32>(name, version, defined, os,
1836                                                    value, symsize, type,
1837                                                    binding, visibility, nonvis,
1838                                                    offset_base, only_if_ref);
1839 #else
1840       gold_unreachable();
1841 #endif
1842     }
1843   else if (parameters->target().get_size() == 64)
1844     {
1845 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1846       return this->do_define_in_output_segment<64>(name, version, defined, os,
1847                                                    value, symsize, type,
1848                                                    binding, visibility, nonvis,
1849                                                    offset_base, only_if_ref);
1850 #else
1851       gold_unreachable();
1852 #endif
1853     }
1854   else
1855     gold_unreachable();
1856 }
1857
1858 // Define a symbol in an Output_segment, sized version.
1859
1860 template<int size>
1861 Sized_symbol<size>*
1862 Symbol_table::do_define_in_output_segment(
1863     const char* name,
1864     const char* version,
1865     Defined defined,
1866     Output_segment* os,
1867     typename elfcpp::Elf_types<size>::Elf_Addr value,
1868     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1869     elfcpp::STT type,
1870     elfcpp::STB binding,
1871     elfcpp::STV visibility,
1872     unsigned char nonvis,
1873     Symbol::Segment_offset_base offset_base,
1874     bool only_if_ref)
1875 {
1876   Sized_symbol<size>* sym;
1877   Sized_symbol<size>* oldsym;
1878   bool resolve_oldsym;
1879
1880   if (parameters->target().is_big_endian())
1881     {
1882 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1883       sym = this->define_special_symbol<size, true>(&name, &version,
1884                                                     only_if_ref, &oldsym,
1885                                                     &resolve_oldsym);
1886 #else
1887       gold_unreachable();
1888 #endif
1889     }
1890   else
1891     {
1892 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1893       sym = this->define_special_symbol<size, false>(&name, &version,
1894                                                      only_if_ref, &oldsym,
1895                                                      &resolve_oldsym);
1896 #else
1897       gold_unreachable();
1898 #endif
1899     }
1900
1901   if (sym == NULL)
1902     return NULL;
1903
1904   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1905                            visibility, nonvis, offset_base);
1906
1907   if (oldsym == NULL)
1908     {
1909       if (binding == elfcpp::STB_LOCAL
1910           || this->version_script_.symbol_is_local(name))
1911         this->force_local(sym);
1912       else if (version != NULL)
1913         sym->set_is_default();
1914       return sym;
1915     }
1916
1917   if (Symbol_table::should_override_with_special(oldsym, defined))
1918     this->override_with_special(oldsym, sym);
1919
1920   if (resolve_oldsym)
1921     return sym;
1922   else
1923     {
1924       delete sym;
1925       return oldsym;
1926     }
1927 }
1928
1929 // Define a special symbol with a constant value.  It is a multiple
1930 // definition error if this symbol is already defined.
1931
1932 Symbol*
1933 Symbol_table::define_as_constant(const char* name,
1934                                  const char* version,
1935                                  Defined defined,
1936                                  uint64_t value,
1937                                  uint64_t symsize,
1938                                  elfcpp::STT type,
1939                                  elfcpp::STB binding,
1940                                  elfcpp::STV visibility,
1941                                  unsigned char nonvis,
1942                                  bool only_if_ref,
1943                                  bool force_override)
1944 {
1945   if (parameters->target().get_size() == 32)
1946     {
1947 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1948       return this->do_define_as_constant<32>(name, version, defined, value,
1949                                              symsize, type, binding,
1950                                              visibility, nonvis, only_if_ref,
1951                                              force_override);
1952 #else
1953       gold_unreachable();
1954 #endif
1955     }
1956   else if (parameters->target().get_size() == 64)
1957     {
1958 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1959       return this->do_define_as_constant<64>(name, version, defined, value,
1960                                              symsize, type, binding,
1961                                              visibility, nonvis, only_if_ref,
1962                                              force_override);
1963 #else
1964       gold_unreachable();
1965 #endif
1966     }
1967   else
1968     gold_unreachable();
1969 }
1970
1971 // Define a symbol as a constant, sized version.
1972
1973 template<int size>
1974 Sized_symbol<size>*
1975 Symbol_table::do_define_as_constant(
1976     const char* name,
1977     const char* version,
1978     Defined defined,
1979     typename elfcpp::Elf_types<size>::Elf_Addr value,
1980     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1981     elfcpp::STT type,
1982     elfcpp::STB binding,
1983     elfcpp::STV visibility,
1984     unsigned char nonvis,
1985     bool only_if_ref,
1986     bool force_override)
1987 {
1988   Sized_symbol<size>* sym;
1989   Sized_symbol<size>* oldsym;
1990   bool resolve_oldsym;
1991
1992   if (parameters->target().is_big_endian())
1993     {
1994 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1995       sym = this->define_special_symbol<size, true>(&name, &version,
1996                                                     only_if_ref, &oldsym,
1997                                                     &resolve_oldsym);
1998 #else
1999       gold_unreachable();
2000 #endif
2001     }
2002   else
2003     {
2004 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2005       sym = this->define_special_symbol<size, false>(&name, &version,
2006                                                      only_if_ref, &oldsym,
2007                                                      &resolve_oldsym);
2008 #else
2009       gold_unreachable();
2010 #endif
2011     }
2012
2013   if (sym == NULL)
2014     return NULL;
2015
2016   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2017                      nonvis);
2018
2019   if (oldsym == NULL)
2020     {
2021       // Version symbols are absolute symbols with name == version.
2022       // We don't want to force them to be local.
2023       if ((version == NULL
2024            || name != version
2025            || value != 0)
2026           && (binding == elfcpp::STB_LOCAL
2027               || this->version_script_.symbol_is_local(name)))
2028         this->force_local(sym);
2029       else if (version != NULL
2030                && (name != version || value != 0))
2031         sym->set_is_default();
2032       return sym;
2033     }
2034
2035   if (force_override
2036       || Symbol_table::should_override_with_special(oldsym, defined))
2037     this->override_with_special(oldsym, sym);
2038
2039   if (resolve_oldsym)
2040     return sym;
2041   else
2042     {
2043       delete sym;
2044       return oldsym;
2045     }
2046 }
2047
2048 // Define a set of symbols in output sections.
2049
2050 void
2051 Symbol_table::define_symbols(const Layout* layout, int count,
2052                              const Define_symbol_in_section* p,
2053                              bool only_if_ref)
2054 {
2055   for (int i = 0; i < count; ++i, ++p)
2056     {
2057       Output_section* os = layout->find_output_section(p->output_section);
2058       if (os != NULL)
2059         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2060                                     p->size, p->type, p->binding,
2061                                     p->visibility, p->nonvis,
2062                                     p->offset_is_from_end,
2063                                     only_if_ref || p->only_if_ref);
2064       else
2065         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2066                                  p->type, p->binding, p->visibility, p->nonvis,
2067                                  only_if_ref || p->only_if_ref,
2068                                  false);
2069     }
2070 }
2071
2072 // Define a set of symbols in output segments.
2073
2074 void
2075 Symbol_table::define_symbols(const Layout* layout, int count,
2076                              const Define_symbol_in_segment* p,
2077                              bool only_if_ref)
2078 {
2079   for (int i = 0; i < count; ++i, ++p)
2080     {
2081       Output_segment* os = layout->find_output_segment(p->segment_type,
2082                                                        p->segment_flags_set,
2083                                                        p->segment_flags_clear);
2084       if (os != NULL)
2085         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2086                                        p->size, p->type, p->binding,
2087                                        p->visibility, p->nonvis,
2088                                        p->offset_base,
2089                                        only_if_ref || p->only_if_ref);
2090       else
2091         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2092                                  p->type, p->binding, p->visibility, p->nonvis,
2093                                  only_if_ref || p->only_if_ref,
2094                                  false);
2095     }
2096 }
2097
2098 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2099 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2100 // the offset within POSD.
2101
2102 template<int size>
2103 void
2104 Symbol_table::define_with_copy_reloc(
2105     Sized_symbol<size>* csym,
2106     Output_data* posd,
2107     typename elfcpp::Elf_types<size>::Elf_Addr value)
2108 {
2109   gold_assert(csym->is_from_dynobj());
2110   gold_assert(!csym->is_copied_from_dynobj());
2111   Object* object = csym->object();
2112   gold_assert(object->is_dynamic());
2113   Dynobj* dynobj = static_cast<Dynobj*>(object);
2114
2115   // Our copied variable has to override any variable in a shared
2116   // library.
2117   elfcpp::STB binding = csym->binding();
2118   if (binding == elfcpp::STB_WEAK)
2119     binding = elfcpp::STB_GLOBAL;
2120
2121   this->define_in_output_data(csym->name(), csym->version(), COPY,
2122                               posd, value, csym->symsize(),
2123                               csym->type(), binding,
2124                               csym->visibility(), csym->nonvis(),
2125                               false, false);
2126
2127   csym->set_is_copied_from_dynobj();
2128   csym->set_needs_dynsym_entry();
2129
2130   this->copied_symbol_dynobjs_[csym] = dynobj;
2131
2132   // We have now defined all aliases, but we have not entered them all
2133   // in the copied_symbol_dynobjs_ map.
2134   if (csym->has_alias())
2135     {
2136       Symbol* sym = csym;
2137       while (true)
2138         {
2139           sym = this->weak_aliases_[sym];
2140           if (sym == csym)
2141             break;
2142           gold_assert(sym->output_data() == posd);
2143
2144           sym->set_is_copied_from_dynobj();
2145           this->copied_symbol_dynobjs_[sym] = dynobj;
2146         }
2147     }
2148 }
2149
2150 // SYM is defined using a COPY reloc.  Return the dynamic object where
2151 // the original definition was found.
2152
2153 Dynobj*
2154 Symbol_table::get_copy_source(const Symbol* sym) const
2155 {
2156   gold_assert(sym->is_copied_from_dynobj());
2157   Copied_symbol_dynobjs::const_iterator p =
2158     this->copied_symbol_dynobjs_.find(sym);
2159   gold_assert(p != this->copied_symbol_dynobjs_.end());
2160   return p->second;
2161 }
2162
2163 // Add any undefined symbols named on the command line.
2164
2165 void
2166 Symbol_table::add_undefined_symbols_from_command_line()
2167 {
2168   if (parameters->options().any_undefined())
2169     {
2170       if (parameters->target().get_size() == 32)
2171         {
2172 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2173           this->do_add_undefined_symbols_from_command_line<32>();
2174 #else
2175           gold_unreachable();
2176 #endif
2177         }
2178       else if (parameters->target().get_size() == 64)
2179         {
2180 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2181           this->do_add_undefined_symbols_from_command_line<64>();
2182 #else
2183           gold_unreachable();
2184 #endif
2185         }
2186       else
2187         gold_unreachable();
2188     }
2189 }
2190
2191 template<int size>
2192 void
2193 Symbol_table::do_add_undefined_symbols_from_command_line()
2194 {
2195   for (options::String_set::const_iterator p =
2196          parameters->options().undefined_begin();
2197        p != parameters->options().undefined_end();
2198        ++p)
2199     {
2200       const char* name = p->c_str();
2201
2202       if (this->lookup(name) != NULL)
2203         continue;
2204
2205       const char* version = NULL;
2206
2207       Sized_symbol<size>* sym;
2208       Sized_symbol<size>* oldsym;
2209       bool resolve_oldsym;
2210       if (parameters->target().is_big_endian())
2211         {
2212 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2213           sym = this->define_special_symbol<size, true>(&name, &version,
2214                                                         false, &oldsym,
2215                                                         &resolve_oldsym);
2216 #else
2217           gold_unreachable();
2218 #endif
2219         }
2220       else
2221         {
2222 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2223           sym = this->define_special_symbol<size, false>(&name, &version,
2224                                                          false, &oldsym,
2225                                                          &resolve_oldsym);
2226 #else
2227           gold_unreachable();
2228 #endif
2229         }
2230
2231       gold_assert(oldsym == NULL);
2232
2233       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2234                           elfcpp::STV_DEFAULT, 0);
2235       ++this->saw_undefined_;
2236     }
2237 }
2238
2239 // Set the dynamic symbol indexes.  INDEX is the index of the first
2240 // global dynamic symbol.  Pointers to the symbols are stored into the
2241 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2242 // updated dynamic symbol index.
2243
2244 unsigned int
2245 Symbol_table::set_dynsym_indexes(unsigned int index,
2246                                  std::vector<Symbol*>* syms,
2247                                  Stringpool* dynpool,
2248                                  Versions* versions)
2249 {
2250   for (Symbol_table_type::iterator p = this->table_.begin();
2251        p != this->table_.end();
2252        ++p)
2253     {
2254       Symbol* sym = p->second;
2255
2256       // Note that SYM may already have a dynamic symbol index, since
2257       // some symbols appear more than once in the symbol table, with
2258       // and without a version.
2259
2260       if (!sym->should_add_dynsym_entry(this))
2261         sym->set_dynsym_index(-1U);
2262       else if (!sym->has_dynsym_index())
2263         {
2264           sym->set_dynsym_index(index);
2265           ++index;
2266           syms->push_back(sym);
2267           dynpool->add(sym->name(), false, NULL);
2268
2269           // Record any version information.
2270           if (sym->version() != NULL)
2271             versions->record_version(this, dynpool, sym);
2272
2273           // If the symbol is defined in a dynamic object and is
2274           // referenced in a regular object, then mark the dynamic
2275           // object as needed.  This is used to implement --as-needed.
2276           if (sym->is_from_dynobj() && sym->in_reg())
2277             sym->object()->set_is_needed();
2278         }
2279     }
2280
2281   // Finish up the versions.  In some cases this may add new dynamic
2282   // symbols.
2283   index = versions->finalize(this, index, syms);
2284
2285   return index;
2286 }
2287
2288 // Set the final values for all the symbols.  The index of the first
2289 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2290 // file offset OFF.  Add their names to POOL.  Return the new file
2291 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2292
2293 off_t
2294 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2295                        size_t dyncount, Stringpool* pool,
2296                        unsigned int *plocal_symcount)
2297 {
2298   off_t ret;
2299
2300   gold_assert(*plocal_symcount != 0);
2301   this->first_global_index_ = *plocal_symcount;
2302
2303   this->dynamic_offset_ = dynoff;
2304   this->first_dynamic_global_index_ = dyn_global_index;
2305   this->dynamic_count_ = dyncount;
2306
2307   if (parameters->target().get_size() == 32)
2308     {
2309 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2310       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2311 #else
2312       gold_unreachable();
2313 #endif
2314     }
2315   else if (parameters->target().get_size() == 64)
2316     {
2317 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2318       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2319 #else
2320       gold_unreachable();
2321 #endif
2322     }
2323   else
2324     gold_unreachable();
2325
2326   // Now that we have the final symbol table, we can reliably note
2327   // which symbols should get warnings.
2328   this->warnings_.note_warnings(this);
2329
2330   return ret;
2331 }
2332
2333 // SYM is going into the symbol table at *PINDEX.  Add the name to
2334 // POOL, update *PINDEX and *POFF.
2335
2336 template<int size>
2337 void
2338 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2339                                   unsigned int* pindex, off_t* poff)
2340 {
2341   sym->set_symtab_index(*pindex);
2342   pool->add(sym->name(), false, NULL);
2343   ++*pindex;
2344   *poff += elfcpp::Elf_sizes<size>::sym_size;
2345 }
2346
2347 // Set the final value for all the symbols.  This is called after
2348 // Layout::finalize, so all the output sections have their final
2349 // address.
2350
2351 template<int size>
2352 off_t
2353 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2354                              unsigned int* plocal_symcount)
2355 {
2356   off = align_address(off, size >> 3);
2357   this->offset_ = off;
2358
2359   unsigned int index = *plocal_symcount;
2360   const unsigned int orig_index = index;
2361
2362   // First do all the symbols which have been forced to be local, as
2363   // they must appear before all global symbols.
2364   for (Forced_locals::iterator p = this->forced_locals_.begin();
2365        p != this->forced_locals_.end();
2366        ++p)
2367     {
2368       Symbol* sym = *p;
2369       gold_assert(sym->is_forced_local());
2370       if (this->sized_finalize_symbol<size>(sym))
2371         {
2372           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2373           ++*plocal_symcount;
2374         }
2375     }
2376
2377   // Now do all the remaining symbols.
2378   for (Symbol_table_type::iterator p = this->table_.begin();
2379        p != this->table_.end();
2380        ++p)
2381     {
2382       Symbol* sym = p->second;
2383       if (this->sized_finalize_symbol<size>(sym))
2384         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2385     }
2386
2387   this->output_count_ = index - orig_index;
2388
2389   return off;
2390 }
2391
2392 // Compute the final value of SYM and store status in location PSTATUS.
2393 // During relaxation, this may be called multiple times for a symbol to
2394 // compute its would-be final value in each relaxation pass.
2395
2396 template<int size>
2397 typename Sized_symbol<size>::Value_type
2398 Symbol_table::compute_final_value(
2399     const Sized_symbol<size>* sym,
2400     Compute_final_value_status* pstatus) const
2401 {
2402   typedef typename Sized_symbol<size>::Value_type Value_type;
2403   Value_type value;
2404
2405   switch (sym->source())
2406     {
2407     case Symbol::FROM_OBJECT:
2408       {
2409         bool is_ordinary;
2410         unsigned int shndx = sym->shndx(&is_ordinary);
2411
2412         if (!is_ordinary
2413             && shndx != elfcpp::SHN_ABS
2414             && !Symbol::is_common_shndx(shndx))
2415           {
2416             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2417             return 0;
2418           }
2419
2420         Object* symobj = sym->object();
2421         if (symobj->is_dynamic())
2422           {
2423             value = 0;
2424             shndx = elfcpp::SHN_UNDEF;
2425           }
2426         else if (symobj->pluginobj() != NULL)
2427           {
2428             value = 0;
2429             shndx = elfcpp::SHN_UNDEF;
2430           }
2431         else if (shndx == elfcpp::SHN_UNDEF)
2432           value = 0;
2433         else if (!is_ordinary
2434                  && (shndx == elfcpp::SHN_ABS
2435                      || Symbol::is_common_shndx(shndx)))
2436           value = sym->value();
2437         else
2438           {
2439             Relobj* relobj = static_cast<Relobj*>(symobj);
2440             Output_section* os = relobj->output_section(shndx);
2441
2442             if (this->is_section_folded(relobj, shndx))
2443               {
2444                 gold_assert(os == NULL);
2445                 // Get the os of the section it is folded onto.
2446                 Section_id folded = this->icf_->get_folded_section(relobj,
2447                                                                    shndx);
2448                 gold_assert(folded.first != NULL);
2449                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2450                 unsigned folded_shndx = folded.second;
2451
2452                 os = folded_obj->output_section(folded_shndx);  
2453                 gold_assert(os != NULL);
2454
2455                 // Replace (relobj, shndx) with canonical ICF input section.
2456                 shndx = folded_shndx;
2457                 relobj = folded_obj;
2458               }
2459
2460             uint64_t secoff64 = relobj->output_section_offset(shndx);
2461             if (os == NULL)
2462               {
2463                 bool static_or_reloc = (parameters->doing_static_link() ||
2464                                         parameters->options().relocatable());
2465                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2466
2467                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2468                 return 0;
2469               }
2470
2471             if (secoff64 == -1ULL)
2472               {
2473                 // The section needs special handling (e.g., a merge section).
2474
2475                 value = os->output_address(relobj, shndx, sym->value());
2476               }
2477             else
2478               {
2479                 Value_type secoff =
2480                   convert_types<Value_type, uint64_t>(secoff64);
2481                 if (sym->type() == elfcpp::STT_TLS)
2482                   value = sym->value() + os->tls_offset() + secoff;
2483                 else
2484                   value = sym->value() + os->address() + secoff;
2485               }
2486           }
2487       }
2488       break;
2489
2490     case Symbol::IN_OUTPUT_DATA:
2491       {
2492         Output_data* od = sym->output_data();
2493         value = sym->value();
2494         if (sym->type() != elfcpp::STT_TLS)
2495           value += od->address();
2496         else
2497           {
2498             Output_section* os = od->output_section();
2499             gold_assert(os != NULL);
2500             value += os->tls_offset() + (od->address() - os->address());
2501           }
2502         if (sym->offset_is_from_end())
2503           value += od->data_size();
2504       }
2505       break;
2506
2507     case Symbol::IN_OUTPUT_SEGMENT:
2508       {
2509         Output_segment* os = sym->output_segment();
2510         value = sym->value();
2511         if (sym->type() != elfcpp::STT_TLS)
2512           value += os->vaddr();
2513         switch (sym->offset_base())
2514           {
2515           case Symbol::SEGMENT_START:
2516             break;
2517           case Symbol::SEGMENT_END:
2518             value += os->memsz();
2519             break;
2520           case Symbol::SEGMENT_BSS:
2521             value += os->filesz();
2522             break;
2523           default:
2524             gold_unreachable();
2525           }
2526       }
2527       break;
2528
2529     case Symbol::IS_CONSTANT:
2530       value = sym->value();
2531       break;
2532
2533     case Symbol::IS_UNDEFINED:
2534       value = 0;
2535       break;
2536
2537     default:
2538       gold_unreachable();
2539     }
2540
2541   *pstatus = CFVS_OK;
2542   return value;
2543 }
2544
2545 // Finalize the symbol SYM.  This returns true if the symbol should be
2546 // added to the symbol table, false otherwise.
2547
2548 template<int size>
2549 bool
2550 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2551 {
2552   typedef typename Sized_symbol<size>::Value_type Value_type;
2553
2554   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2555
2556   // The default version of a symbol may appear twice in the symbol
2557   // table.  We only need to finalize it once.
2558   if (sym->has_symtab_index())
2559     return false;
2560
2561   if (!sym->in_reg())
2562     {
2563       gold_assert(!sym->has_symtab_index());
2564       sym->set_symtab_index(-1U);
2565       gold_assert(sym->dynsym_index() == -1U);
2566       return false;
2567     }
2568
2569   // Compute final symbol value.
2570   Compute_final_value_status status;
2571   Value_type value = this->compute_final_value(sym, &status);
2572
2573   switch (status)
2574     {
2575     case CFVS_OK:
2576       break;
2577     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2578       {
2579         bool is_ordinary;
2580         unsigned int shndx = sym->shndx(&is_ordinary);
2581         gold_error(_("%s: unsupported symbol section 0x%x"),
2582                    sym->demangled_name().c_str(), shndx);
2583       }
2584       break;
2585     case CFVS_NO_OUTPUT_SECTION:
2586       sym->set_symtab_index(-1U);
2587       return false;
2588     default:
2589       gold_unreachable();
2590     }
2591
2592   sym->set_value(value);
2593
2594   if (parameters->options().strip_all()
2595       || !parameters->options().should_retain_symbol(sym->name()))
2596     {
2597       sym->set_symtab_index(-1U);
2598       return false;
2599     }
2600
2601   return true;
2602 }
2603
2604 // Write out the global symbols.
2605
2606 void
2607 Symbol_table::write_globals(const Stringpool* sympool,
2608                             const Stringpool* dynpool,
2609                             Output_symtab_xindex* symtab_xindex,
2610                             Output_symtab_xindex* dynsym_xindex,
2611                             Output_file* of) const
2612 {
2613   switch (parameters->size_and_endianness())
2614     {
2615 #ifdef HAVE_TARGET_32_LITTLE
2616     case Parameters::TARGET_32_LITTLE:
2617       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2618                                            dynsym_xindex, of);
2619       break;
2620 #endif
2621 #ifdef HAVE_TARGET_32_BIG
2622     case Parameters::TARGET_32_BIG:
2623       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2624                                           dynsym_xindex, of);
2625       break;
2626 #endif
2627 #ifdef HAVE_TARGET_64_LITTLE
2628     case Parameters::TARGET_64_LITTLE:
2629       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2630                                            dynsym_xindex, of);
2631       break;
2632 #endif
2633 #ifdef HAVE_TARGET_64_BIG
2634     case Parameters::TARGET_64_BIG:
2635       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2636                                           dynsym_xindex, of);
2637       break;
2638 #endif
2639     default:
2640       gold_unreachable();
2641     }
2642 }
2643
2644 // Write out the global symbols.
2645
2646 template<int size, bool big_endian>
2647 void
2648 Symbol_table::sized_write_globals(const Stringpool* sympool,
2649                                   const Stringpool* dynpool,
2650                                   Output_symtab_xindex* symtab_xindex,
2651                                   Output_symtab_xindex* dynsym_xindex,
2652                                   Output_file* of) const
2653 {
2654   const Target& target = parameters->target();
2655
2656   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2657
2658   const unsigned int output_count = this->output_count_;
2659   const section_size_type oview_size = output_count * sym_size;
2660   const unsigned int first_global_index = this->first_global_index_;
2661   unsigned char* psyms;
2662   if (this->offset_ == 0 || output_count == 0)
2663     psyms = NULL;
2664   else
2665     psyms = of->get_output_view(this->offset_, oview_size);
2666
2667   const unsigned int dynamic_count = this->dynamic_count_;
2668   const section_size_type dynamic_size = dynamic_count * sym_size;
2669   const unsigned int first_dynamic_global_index =
2670     this->first_dynamic_global_index_;
2671   unsigned char* dynamic_view;
2672   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2673     dynamic_view = NULL;
2674   else
2675     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2676
2677   for (Symbol_table_type::const_iterator p = this->table_.begin();
2678        p != this->table_.end();
2679        ++p)
2680     {
2681       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2682
2683       // Possibly warn about unresolved symbols in shared libraries.
2684       this->warn_about_undefined_dynobj_symbol(sym);
2685
2686       unsigned int sym_index = sym->symtab_index();
2687       unsigned int dynsym_index;
2688       if (dynamic_view == NULL)
2689         dynsym_index = -1U;
2690       else
2691         dynsym_index = sym->dynsym_index();
2692
2693       if (sym_index == -1U && dynsym_index == -1U)
2694         {
2695           // This symbol is not included in the output file.
2696           continue;
2697         }
2698
2699       unsigned int shndx;
2700       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2701       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2702       elfcpp::STB binding = sym->binding();
2703       switch (sym->source())
2704         {
2705         case Symbol::FROM_OBJECT:
2706           {
2707             bool is_ordinary;
2708             unsigned int in_shndx = sym->shndx(&is_ordinary);
2709
2710             if (!is_ordinary
2711                 && in_shndx != elfcpp::SHN_ABS
2712                 && !Symbol::is_common_shndx(in_shndx))
2713               {
2714                 gold_error(_("%s: unsupported symbol section 0x%x"),
2715                            sym->demangled_name().c_str(), in_shndx);
2716                 shndx = in_shndx;
2717               }
2718             else
2719               {
2720                 Object* symobj = sym->object();
2721                 if (symobj->is_dynamic())
2722                   {
2723                     if (sym->needs_dynsym_value())
2724                       dynsym_value = target.dynsym_value(sym);
2725                     shndx = elfcpp::SHN_UNDEF;
2726                     if (sym->is_undef_binding_weak())
2727                       binding = elfcpp::STB_WEAK;
2728                   }
2729                 else if (symobj->pluginobj() != NULL)
2730                   shndx = elfcpp::SHN_UNDEF;
2731                 else if (in_shndx == elfcpp::SHN_UNDEF
2732                          || (!is_ordinary
2733                              && (in_shndx == elfcpp::SHN_ABS
2734                                  || Symbol::is_common_shndx(in_shndx))))
2735                   shndx = in_shndx;
2736                 else
2737                   {
2738                     Relobj* relobj = static_cast<Relobj*>(symobj);
2739                     Output_section* os = relobj->output_section(in_shndx);
2740                     if (this->is_section_folded(relobj, in_shndx))
2741                       {
2742                         // This global symbol must be written out even though
2743                         // it is folded.
2744                         // Get the os of the section it is folded onto.
2745                         Section_id folded =
2746                              this->icf_->get_folded_section(relobj, in_shndx);
2747                         gold_assert(folded.first !=NULL);
2748                         Relobj* folded_obj = 
2749                           reinterpret_cast<Relobj*>(folded.first);
2750                         os = folded_obj->output_section(folded.second);  
2751                         gold_assert(os != NULL);
2752                       }
2753                     gold_assert(os != NULL);
2754                     shndx = os->out_shndx();
2755
2756                     if (shndx >= elfcpp::SHN_LORESERVE)
2757                       {
2758                         if (sym_index != -1U)
2759                           symtab_xindex->add(sym_index, shndx);
2760                         if (dynsym_index != -1U)
2761                           dynsym_xindex->add(dynsym_index, shndx);
2762                         shndx = elfcpp::SHN_XINDEX;
2763                       }
2764
2765                     // In object files symbol values are section
2766                     // relative.
2767                     if (parameters->options().relocatable())
2768                       sym_value -= os->address();
2769                   }
2770               }
2771           }
2772           break;
2773
2774         case Symbol::IN_OUTPUT_DATA:
2775           shndx = sym->output_data()->out_shndx();
2776           if (shndx >= elfcpp::SHN_LORESERVE)
2777             {
2778               if (sym_index != -1U)
2779                 symtab_xindex->add(sym_index, shndx);
2780               if (dynsym_index != -1U)
2781                 dynsym_xindex->add(dynsym_index, shndx);
2782               shndx = elfcpp::SHN_XINDEX;
2783             }
2784           break;
2785
2786         case Symbol::IN_OUTPUT_SEGMENT:
2787           shndx = elfcpp::SHN_ABS;
2788           break;
2789
2790         case Symbol::IS_CONSTANT:
2791           shndx = elfcpp::SHN_ABS;
2792           break;
2793
2794         case Symbol::IS_UNDEFINED:
2795           shndx = elfcpp::SHN_UNDEF;
2796           break;
2797
2798         default:
2799           gold_unreachable();
2800         }
2801
2802       if (sym_index != -1U)
2803         {
2804           sym_index -= first_global_index;
2805           gold_assert(sym_index < output_count);
2806           unsigned char* ps = psyms + (sym_index * sym_size);
2807           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2808                                                      binding, sympool, ps);
2809         }
2810
2811       if (dynsym_index != -1U)
2812         {
2813           dynsym_index -= first_dynamic_global_index;
2814           gold_assert(dynsym_index < dynamic_count);
2815           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2816           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2817                                                      binding, dynpool, pd);
2818         }
2819     }
2820
2821   of->write_output_view(this->offset_, oview_size, psyms);
2822   if (dynamic_view != NULL)
2823     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2824 }
2825
2826 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2827 // strtab holding the name.
2828
2829 template<int size, bool big_endian>
2830 void
2831 Symbol_table::sized_write_symbol(
2832     Sized_symbol<size>* sym,
2833     typename elfcpp::Elf_types<size>::Elf_Addr value,
2834     unsigned int shndx,
2835     elfcpp::STB binding,
2836     const Stringpool* pool,
2837     unsigned char* p) const
2838 {
2839   elfcpp::Sym_write<size, big_endian> osym(p);
2840   osym.put_st_name(pool->get_offset(sym->name()));
2841   osym.put_st_value(value);
2842   // Use a symbol size of zero for undefined symbols from shared libraries.
2843   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2844     osym.put_st_size(0);
2845   else
2846     osym.put_st_size(sym->symsize());
2847   elfcpp::STT type = sym->type();
2848   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2849   if (type == elfcpp::STT_GNU_IFUNC
2850       && sym->is_from_dynobj())
2851     type = elfcpp::STT_FUNC;
2852   // A version script may have overridden the default binding.
2853   if (sym->is_forced_local())
2854     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2855   else
2856     osym.put_st_info(elfcpp::elf_st_info(binding, type));
2857   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2858   osym.put_st_shndx(shndx);
2859 }
2860
2861 // Check for unresolved symbols in shared libraries.  This is
2862 // controlled by the --allow-shlib-undefined option.
2863
2864 // We only warn about libraries for which we have seen all the
2865 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2866 // which were not seen in this link.  If we didn't see a DT_NEEDED
2867 // entry, we aren't going to be able to reliably report whether the
2868 // symbol is undefined.
2869
2870 // We also don't warn about libraries found in a system library
2871 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2872 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2873 // can have undefined references satisfied by ld-linux.so.
2874
2875 inline void
2876 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2877 {
2878   bool dummy;
2879   if (sym->source() == Symbol::FROM_OBJECT
2880       && sym->object()->is_dynamic()
2881       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2882       && sym->binding() != elfcpp::STB_WEAK
2883       && !parameters->options().allow_shlib_undefined()
2884       && !parameters->target().is_defined_by_abi(sym)
2885       && !sym->object()->is_in_system_directory())
2886     {
2887       // A very ugly cast.
2888       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2889       if (!dynobj->has_unknown_needed_entries())
2890         gold_undefined_symbol(sym);
2891     }
2892 }
2893
2894 // Write out a section symbol.  Return the update offset.
2895
2896 void
2897 Symbol_table::write_section_symbol(const Output_section *os,
2898                                    Output_symtab_xindex* symtab_xindex,
2899                                    Output_file* of,
2900                                    off_t offset) const
2901 {
2902   switch (parameters->size_and_endianness())
2903     {
2904 #ifdef HAVE_TARGET_32_LITTLE
2905     case Parameters::TARGET_32_LITTLE:
2906       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2907                                                   offset);
2908       break;
2909 #endif
2910 #ifdef HAVE_TARGET_32_BIG
2911     case Parameters::TARGET_32_BIG:
2912       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2913                                                  offset);
2914       break;
2915 #endif
2916 #ifdef HAVE_TARGET_64_LITTLE
2917     case Parameters::TARGET_64_LITTLE:
2918       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2919                                                   offset);
2920       break;
2921 #endif
2922 #ifdef HAVE_TARGET_64_BIG
2923     case Parameters::TARGET_64_BIG:
2924       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2925                                                  offset);
2926       break;
2927 #endif
2928     default:
2929       gold_unreachable();
2930     }
2931 }
2932
2933 // Write out a section symbol, specialized for size and endianness.
2934
2935 template<int size, bool big_endian>
2936 void
2937 Symbol_table::sized_write_section_symbol(const Output_section* os,
2938                                          Output_symtab_xindex* symtab_xindex,
2939                                          Output_file* of,
2940                                          off_t offset) const
2941 {
2942   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2943
2944   unsigned char* pov = of->get_output_view(offset, sym_size);
2945
2946   elfcpp::Sym_write<size, big_endian> osym(pov);
2947   osym.put_st_name(0);
2948   if (parameters->options().relocatable())
2949     osym.put_st_value(0);
2950   else
2951     osym.put_st_value(os->address());
2952   osym.put_st_size(0);
2953   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2954                                        elfcpp::STT_SECTION));
2955   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2956
2957   unsigned int shndx = os->out_shndx();
2958   if (shndx >= elfcpp::SHN_LORESERVE)
2959     {
2960       symtab_xindex->add(os->symtab_index(), shndx);
2961       shndx = elfcpp::SHN_XINDEX;
2962     }
2963   osym.put_st_shndx(shndx);
2964
2965   of->write_output_view(offset, sym_size, pov);
2966 }
2967
2968 // Print statistical information to stderr.  This is used for --stats.
2969
2970 void
2971 Symbol_table::print_stats() const
2972 {
2973 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2974   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2975           program_name, this->table_.size(), this->table_.bucket_count());
2976 #else
2977   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2978           program_name, this->table_.size());
2979 #endif
2980   this->namepool_.print_stats("symbol table stringpool");
2981 }
2982
2983 // We check for ODR violations by looking for symbols with the same
2984 // name for which the debugging information reports that they were
2985 // defined in different source locations.  When comparing the source
2986 // location, we consider instances with the same base filename and
2987 // line number to be the same.  This is because different object
2988 // files/shared libraries can include the same header file using
2989 // different paths, and we don't want to report an ODR violation in
2990 // that case.
2991
2992 // This struct is used to compare line information, as returned by
2993 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2994 // operator used with std::set.
2995
2996 struct Odr_violation_compare
2997 {
2998   bool
2999   operator()(const std::string& s1, const std::string& s2) const
3000   {
3001     std::string::size_type pos1 = s1.rfind('/');
3002     std::string::size_type pos2 = s2.rfind('/');
3003     if (pos1 == std::string::npos
3004         || pos2 == std::string::npos)
3005       return s1 < s2;
3006     return s1.compare(pos1, std::string::npos,
3007                       s2, pos2, std::string::npos) < 0;
3008   }
3009 };
3010
3011 // Check candidate_odr_violations_ to find symbols with the same name
3012 // but apparently different definitions (different source-file/line-no).
3013
3014 void
3015 Symbol_table::detect_odr_violations(const Task* task,
3016                                     const char* output_file_name) const
3017 {
3018   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3019        it != candidate_odr_violations_.end();
3020        ++it)
3021     {
3022       const char* symbol_name = it->first;
3023       // Maps from symbol location to a sample object file we found
3024       // that location in.  We use a sorted map so the location order
3025       // is deterministic, but we only store an arbitrary object file
3026       // to avoid copying lots of names.
3027       std::map<std::string, std::string, Odr_violation_compare> line_nums;
3028
3029       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3030                locs = it->second.begin();
3031            locs != it->second.end();
3032            ++locs)
3033         {
3034           // We need to lock the object in order to read it.  This
3035           // means that we have to run in a singleton Task.  If we
3036           // want to run this in a general Task for better
3037           // performance, we will need one Task for object, plus
3038           // appropriate locking to ensure that we don't conflict with
3039           // other uses of the object.  Also note, one_addr2line is not
3040           // currently thread-safe.
3041           Task_lock_obj<Object> tl(task, locs->object);
3042           // 16 is the size of the object-cache that one_addr2line should use.
3043           std::string lineno = Dwarf_line_info::one_addr2line(
3044               locs->object, locs->shndx, locs->offset, 16);
3045           if (!lineno.empty())
3046             {
3047               std::string& sample_object = line_nums[lineno];
3048               if (sample_object.empty())
3049                 sample_object = locs->object->name();
3050             }
3051         }
3052
3053       if (line_nums.size() > 1)
3054         {
3055           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3056                          "places (possible ODR violation):"),
3057                        output_file_name, demangle(symbol_name).c_str());
3058           for (std::map<std::string, std::string>::const_iterator it2 =
3059                  line_nums.begin();
3060                it2 != line_nums.end();
3061                ++it2)
3062             fprintf(stderr, _("  %s from %s\n"),
3063                     it2->first.c_str(), it2->second.c_str());
3064         }
3065     }
3066   // We only call one_addr2line() in this function, so we can clear its cache.
3067   Dwarf_line_info::clear_addr2line_cache();
3068 }
3069
3070 // Warnings functions.
3071
3072 // Add a new warning.
3073
3074 void
3075 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3076                       const std::string& warning)
3077 {
3078   name = symtab->canonicalize_name(name);
3079   this->warnings_[name].set(obj, warning);
3080 }
3081
3082 // Look through the warnings and mark the symbols for which we should
3083 // warn.  This is called during Layout::finalize when we know the
3084 // sources for all the symbols.
3085
3086 void
3087 Warnings::note_warnings(Symbol_table* symtab)
3088 {
3089   for (Warning_table::iterator p = this->warnings_.begin();
3090        p != this->warnings_.end();
3091        ++p)
3092     {
3093       Symbol* sym = symtab->lookup(p->first, NULL);
3094       if (sym != NULL
3095           && sym->source() == Symbol::FROM_OBJECT
3096           && sym->object() == p->second.object)
3097         sym->set_has_warning();
3098     }
3099 }
3100
3101 // Issue a warning.  This is called when we see a relocation against a
3102 // symbol for which has a warning.
3103
3104 template<int size, bool big_endian>
3105 void
3106 Warnings::issue_warning(const Symbol* sym,
3107                         const Relocate_info<size, big_endian>* relinfo,
3108                         size_t relnum, off_t reloffset) const
3109 {
3110   gold_assert(sym->has_warning());
3111   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3112   gold_assert(p != this->warnings_.end());
3113   gold_warning_at_location(relinfo, relnum, reloffset,
3114                            "%s", p->second.text.c_str());
3115 }
3116
3117 // Instantiate the templates we need.  We could use the configure
3118 // script to restrict this to only the ones needed for implemented
3119 // targets.
3120
3121 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3122 template
3123 void
3124 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3125 #endif
3126
3127 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3128 template
3129 void
3130 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3131 #endif
3132
3133 #ifdef HAVE_TARGET_32_LITTLE
3134 template
3135 void
3136 Symbol_table::add_from_relobj<32, false>(
3137     Sized_relobj<32, false>* relobj,
3138     const unsigned char* syms,
3139     size_t count,
3140     size_t symndx_offset,
3141     const char* sym_names,
3142     size_t sym_name_size,
3143     Sized_relobj<32, false>::Symbols* sympointers,
3144     size_t* defined);
3145 #endif
3146
3147 #ifdef HAVE_TARGET_32_BIG
3148 template
3149 void
3150 Symbol_table::add_from_relobj<32, true>(
3151     Sized_relobj<32, true>* relobj,
3152     const unsigned char* syms,
3153     size_t count,
3154     size_t symndx_offset,
3155     const char* sym_names,
3156     size_t sym_name_size,
3157     Sized_relobj<32, true>::Symbols* sympointers,
3158     size_t* defined);
3159 #endif
3160
3161 #ifdef HAVE_TARGET_64_LITTLE
3162 template
3163 void
3164 Symbol_table::add_from_relobj<64, false>(
3165     Sized_relobj<64, false>* relobj,
3166     const unsigned char* syms,
3167     size_t count,
3168     size_t symndx_offset,
3169     const char* sym_names,
3170     size_t sym_name_size,
3171     Sized_relobj<64, false>::Symbols* sympointers,
3172     size_t* defined);
3173 #endif
3174
3175 #ifdef HAVE_TARGET_64_BIG
3176 template
3177 void
3178 Symbol_table::add_from_relobj<64, true>(
3179     Sized_relobj<64, true>* relobj,
3180     const unsigned char* syms,
3181     size_t count,
3182     size_t symndx_offset,
3183     const char* sym_names,
3184     size_t sym_name_size,
3185     Sized_relobj<64, true>::Symbols* sympointers,
3186     size_t* defined);
3187 #endif
3188
3189 #ifdef HAVE_TARGET_32_LITTLE
3190 template
3191 Symbol*
3192 Symbol_table::add_from_pluginobj<32, false>(
3193     Sized_pluginobj<32, false>* obj,
3194     const char* name,
3195     const char* ver,
3196     elfcpp::Sym<32, false>* sym);
3197 #endif
3198
3199 #ifdef HAVE_TARGET_32_BIG
3200 template
3201 Symbol*
3202 Symbol_table::add_from_pluginobj<32, true>(
3203     Sized_pluginobj<32, true>* obj,
3204     const char* name,
3205     const char* ver,
3206     elfcpp::Sym<32, true>* sym);
3207 #endif
3208
3209 #ifdef HAVE_TARGET_64_LITTLE
3210 template
3211 Symbol*
3212 Symbol_table::add_from_pluginobj<64, false>(
3213     Sized_pluginobj<64, false>* obj,
3214     const char* name,
3215     const char* ver,
3216     elfcpp::Sym<64, false>* sym);
3217 #endif
3218
3219 #ifdef HAVE_TARGET_64_BIG
3220 template
3221 Symbol*
3222 Symbol_table::add_from_pluginobj<64, true>(
3223     Sized_pluginobj<64, true>* obj,
3224     const char* name,
3225     const char* ver,
3226     elfcpp::Sym<64, true>* sym);
3227 #endif
3228
3229 #ifdef HAVE_TARGET_32_LITTLE
3230 template
3231 void
3232 Symbol_table::add_from_dynobj<32, false>(
3233     Sized_dynobj<32, false>* dynobj,
3234     const unsigned char* syms,
3235     size_t count,
3236     const char* sym_names,
3237     size_t sym_name_size,
3238     const unsigned char* versym,
3239     size_t versym_size,
3240     const std::vector<const char*>* version_map,
3241     Sized_relobj<32, false>::Symbols* sympointers,
3242     size_t* defined);
3243 #endif
3244
3245 #ifdef HAVE_TARGET_32_BIG
3246 template
3247 void
3248 Symbol_table::add_from_dynobj<32, true>(
3249     Sized_dynobj<32, true>* dynobj,
3250     const unsigned char* syms,
3251     size_t count,
3252     const char* sym_names,
3253     size_t sym_name_size,
3254     const unsigned char* versym,
3255     size_t versym_size,
3256     const std::vector<const char*>* version_map,
3257     Sized_relobj<32, true>::Symbols* sympointers,
3258     size_t* defined);
3259 #endif
3260
3261 #ifdef HAVE_TARGET_64_LITTLE
3262 template
3263 void
3264 Symbol_table::add_from_dynobj<64, false>(
3265     Sized_dynobj<64, false>* dynobj,
3266     const unsigned char* syms,
3267     size_t count,
3268     const char* sym_names,
3269     size_t sym_name_size,
3270     const unsigned char* versym,
3271     size_t versym_size,
3272     const std::vector<const char*>* version_map,
3273     Sized_relobj<64, false>::Symbols* sympointers,
3274     size_t* defined);
3275 #endif
3276
3277 #ifdef HAVE_TARGET_64_BIG
3278 template
3279 void
3280 Symbol_table::add_from_dynobj<64, true>(
3281     Sized_dynobj<64, true>* dynobj,
3282     const unsigned char* syms,
3283     size_t count,
3284     const char* sym_names,
3285     size_t sym_name_size,
3286     const unsigned char* versym,
3287     size_t versym_size,
3288     const std::vector<const char*>* version_map,
3289     Sized_relobj<64, true>::Symbols* sympointers,
3290     size_t* defined);
3291 #endif
3292
3293 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3294 template
3295 void
3296 Symbol_table::define_with_copy_reloc<32>(
3297     Sized_symbol<32>* sym,
3298     Output_data* posd,
3299     elfcpp::Elf_types<32>::Elf_Addr value);
3300 #endif
3301
3302 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3303 template
3304 void
3305 Symbol_table::define_with_copy_reloc<64>(
3306     Sized_symbol<64>* sym,
3307     Output_data* posd,
3308     elfcpp::Elf_types<64>::Elf_Addr value);
3309 #endif
3310
3311 #ifdef HAVE_TARGET_32_LITTLE
3312 template
3313 void
3314 Warnings::issue_warning<32, false>(const Symbol* sym,
3315                                    const Relocate_info<32, false>* relinfo,
3316                                    size_t relnum, off_t reloffset) const;
3317 #endif
3318
3319 #ifdef HAVE_TARGET_32_BIG
3320 template
3321 void
3322 Warnings::issue_warning<32, true>(const Symbol* sym,
3323                                   const Relocate_info<32, true>* relinfo,
3324                                   size_t relnum, off_t reloffset) const;
3325 #endif
3326
3327 #ifdef HAVE_TARGET_64_LITTLE
3328 template
3329 void
3330 Warnings::issue_warning<64, false>(const Symbol* sym,
3331                                    const Relocate_info<64, false>* relinfo,
3332                                    size_t relnum, off_t reloffset) const;
3333 #endif
3334
3335 #ifdef HAVE_TARGET_64_BIG
3336 template
3337 void
3338 Warnings::issue_warning<64, true>(const Symbol* sym,
3339                                   const Relocate_info<64, true>* relinfo,
3340                                   size_t relnum, off_t reloffset) const;
3341 #endif
3342
3343 } // End namespace gold.