]> Git Repo - binutils.git/blob - gold/symtab.cc
2010-01-22 Viktor Kutuzov <[email protected]>
[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 <[email protected]>.
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 }
80
81 // Return the demangled version of the symbol's name, but only
82 // if the --demangle flag was set.
83
84 static std::string
85 demangle(const char* name)
86 {
87   if (!parameters->options().do_demangle())
88     return name;
89
90   // cplus_demangle allocates memory for the result it returns,
91   // and returns NULL if the name is already demangled.
92   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
93   if (demangled_name == NULL)
94     return name;
95
96   std::string retval(demangled_name);
97   free(demangled_name);
98   return retval;
99 }
100
101 std::string
102 Symbol::demangled_name() const
103 {
104   return demangle(this->name());
105 }
106
107 // Initialize the fields in the base class Symbol for SYM in OBJECT.
108
109 template<int size, bool big_endian>
110 void
111 Symbol::init_base_object(const char* name, const char* version, Object* object,
112                          const elfcpp::Sym<size, big_endian>& sym,
113                          unsigned int st_shndx, bool is_ordinary)
114 {
115   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
116                     sym.get_st_visibility(), sym.get_st_nonvis());
117   this->u_.from_object.object = object;
118   this->u_.from_object.shndx = st_shndx;
119   this->is_ordinary_shndx_ = is_ordinary;
120   this->source_ = FROM_OBJECT;
121   this->in_reg_ = !object->is_dynamic();
122   this->in_dyn_ = object->is_dynamic();
123   this->in_real_elf_ = object->pluginobj() == NULL;
124 }
125
126 // Initialize the fields in the base class Symbol for a symbol defined
127 // in an Output_data.
128
129 void
130 Symbol::init_base_output_data(const char* name, const char* version,
131                               Output_data* od, elfcpp::STT type,
132                               elfcpp::STB binding, elfcpp::STV visibility,
133                               unsigned char nonvis, bool offset_is_from_end)
134 {
135   this->init_fields(name, version, type, binding, visibility, nonvis);
136   this->u_.in_output_data.output_data = od;
137   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
138   this->source_ = IN_OUTPUT_DATA;
139   this->in_reg_ = true;
140   this->in_real_elf_ = true;
141 }
142
143 // Initialize the fields in the base class Symbol for a symbol defined
144 // in an Output_segment.
145
146 void
147 Symbol::init_base_output_segment(const char* name, const char* version,
148                                  Output_segment* os, elfcpp::STT type,
149                                  elfcpp::STB binding, elfcpp::STV visibility,
150                                  unsigned char nonvis,
151                                  Segment_offset_base offset_base)
152 {
153   this->init_fields(name, version, type, binding, visibility, nonvis);
154   this->u_.in_output_segment.output_segment = os;
155   this->u_.in_output_segment.offset_base = offset_base;
156   this->source_ = IN_OUTPUT_SEGMENT;
157   this->in_reg_ = true;
158   this->in_real_elf_ = true;
159 }
160
161 // Initialize the fields in the base class Symbol for a symbol defined
162 // as a constant.
163
164 void
165 Symbol::init_base_constant(const char* name, const char* version,
166                            elfcpp::STT type, elfcpp::STB binding,
167                            elfcpp::STV visibility, unsigned char nonvis)
168 {
169   this->init_fields(name, version, type, binding, visibility, nonvis);
170   this->source_ = IS_CONSTANT;
171   this->in_reg_ = true;
172   this->in_real_elf_ = true;
173 }
174
175 // Initialize the fields in the base class Symbol for an undefined
176 // symbol.
177
178 void
179 Symbol::init_base_undefined(const char* name, const char* version,
180                             elfcpp::STT type, elfcpp::STB binding,
181                             elfcpp::STV visibility, unsigned char nonvis)
182 {
183   this->init_fields(name, version, type, binding, visibility, nonvis);
184   this->dynsym_index_ = -1U;
185   this->source_ = IS_UNDEFINED;
186   this->in_reg_ = true;
187   this->in_real_elf_ = true;
188 }
189
190 // Allocate a common symbol in the base.
191
192 void
193 Symbol::allocate_base_common(Output_data* od)
194 {
195   gold_assert(this->is_common());
196   this->source_ = IN_OUTPUT_DATA;
197   this->u_.in_output_data.output_data = od;
198   this->u_.in_output_data.offset_is_from_end = false;
199 }
200
201 // Initialize the fields in Sized_symbol for SYM in OBJECT.
202
203 template<int size>
204 template<bool big_endian>
205 void
206 Sized_symbol<size>::init_object(const char* name, const char* version,
207                                 Object* object,
208                                 const elfcpp::Sym<size, big_endian>& sym,
209                                 unsigned int st_shndx, bool is_ordinary)
210 {
211   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
212   this->value_ = sym.get_st_value();
213   this->symsize_ = sym.get_st_size();
214 }
215
216 // Initialize the fields in Sized_symbol for a symbol defined in an
217 // Output_data.
218
219 template<int size>
220 void
221 Sized_symbol<size>::init_output_data(const char* name, const char* version,
222                                      Output_data* od, Value_type value,
223                                      Size_type symsize, elfcpp::STT type,
224                                      elfcpp::STB binding,
225                                      elfcpp::STV visibility,
226                                      unsigned char nonvis,
227                                      bool offset_is_from_end)
228 {
229   this->init_base_output_data(name, version, od, type, binding, visibility,
230                               nonvis, offset_is_from_end);
231   this->value_ = value;
232   this->symsize_ = symsize;
233 }
234
235 // Initialize the fields in Sized_symbol for a symbol defined in an
236 // Output_segment.
237
238 template<int size>
239 void
240 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
241                                         Output_segment* os, Value_type value,
242                                         Size_type symsize, elfcpp::STT type,
243                                         elfcpp::STB binding,
244                                         elfcpp::STV visibility,
245                                         unsigned char nonvis,
246                                         Segment_offset_base offset_base)
247 {
248   this->init_base_output_segment(name, version, os, type, binding, visibility,
249                                  nonvis, offset_base);
250   this->value_ = value;
251   this->symsize_ = symsize;
252 }
253
254 // Initialize the fields in Sized_symbol for a symbol defined as a
255 // constant.
256
257 template<int size>
258 void
259 Sized_symbol<size>::init_constant(const char* name, const char* version,
260                                   Value_type value, Size_type symsize,
261                                   elfcpp::STT type, elfcpp::STB binding,
262                                   elfcpp::STV visibility, unsigned char nonvis)
263 {
264   this->init_base_constant(name, version, type, binding, visibility, nonvis);
265   this->value_ = value;
266   this->symsize_ = symsize;
267 }
268
269 // Initialize the fields in Sized_symbol for an undefined symbol.
270
271 template<int size>
272 void
273 Sized_symbol<size>::init_undefined(const char* name, const char* version,
274                                    elfcpp::STT type, elfcpp::STB binding,
275                                    elfcpp::STV visibility, unsigned char nonvis)
276 {
277   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
278   this->value_ = 0;
279   this->symsize_ = 0;
280 }
281
282 // Return true if SHNDX represents a common symbol.
283
284 bool
285 Symbol::is_common_shndx(unsigned int shndx)
286 {
287   return (shndx == elfcpp::SHN_COMMON
288           || shndx == parameters->target().small_common_shndx()
289           || shndx == parameters->target().large_common_shndx());
290 }
291
292 // Allocate a common symbol.
293
294 template<int size>
295 void
296 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
297 {
298   this->allocate_base_common(od);
299   this->value_ = value;
300 }
301
302 // The ""'s around str ensure str is a string literal, so sizeof works.
303 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
304
305 // Return true if this symbol should be added to the dynamic symbol
306 // table.
307
308 inline bool
309 Symbol::should_add_dynsym_entry() const
310 {
311   // If the symbol is used by a dynamic relocation, we need to add it.
312   if (this->needs_dynsym_entry())
313     return true;
314
315   // If this symbol's section is not added, the symbol need not be added. 
316   // The section may have been GCed.  Note that export_dynamic is being 
317   // overridden here.  This should not be done for shared objects.
318   if (parameters->options().gc_sections() 
319       && !parameters->options().shared()
320       && this->source() == Symbol::FROM_OBJECT
321       && !this->object()->is_dynamic())
322     {
323       Relobj* relobj = static_cast<Relobj*>(this->object());
324       bool is_ordinary;
325       unsigned int shndx = this->shndx(&is_ordinary);
326       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
327           && !relobj->is_section_included(shndx))
328         return false;
329     }
330
331   // If the symbol was forced local in a version script, do not add it.
332   if (this->is_forced_local())
333     return false;
334
335   // If the symbol was forced dynamic in a --dynamic-list file, add it.
336   if (parameters->options().in_dynamic_list(this->name()))
337     return true;
338
339   // If dynamic-list-data was specified, add any STT_OBJECT.
340   if (parameters->options().dynamic_list_data()
341       && !this->is_from_dynobj()
342       && this->type() == elfcpp::STT_OBJECT)
343     return true;
344
345   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
346   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
347   if ((parameters->options().dynamic_list_cpp_new()
348        || parameters->options().dynamic_list_cpp_typeinfo())
349       && !this->is_from_dynobj())
350     {
351       // TODO(csilvers): We could probably figure out if we're an operator
352       //                 new/delete or typeinfo without the need to demangle.
353       char* demangled_name = cplus_demangle(this->name(),
354                                             DMGL_ANSI | DMGL_PARAMS);
355       if (demangled_name == NULL)
356         {
357           // Not a C++ symbol, so it can't satisfy these flags
358         }
359       else if (parameters->options().dynamic_list_cpp_new()
360                && (strprefix(demangled_name, "operator new")
361                    || strprefix(demangled_name, "operator delete")))
362         {
363           free(demangled_name);
364           return true;
365         }
366       else if (parameters->options().dynamic_list_cpp_typeinfo()
367                && (strprefix(demangled_name, "typeinfo name for")
368                    || strprefix(demangled_name, "typeinfo for")))
369         {
370           free(demangled_name);
371           return true;
372         }
373       else
374         free(demangled_name);
375     }
376
377   // If exporting all symbols or building a shared library,
378   // and the symbol is defined in a regular object and is
379   // externally visible, we need to add it.
380   if ((parameters->options().export_dynamic() || parameters->options().shared())
381       && !this->is_from_dynobj()
382       && this->is_externally_visible())
383     return true;
384
385   return false;
386 }
387
388 // Return true if the final value of this symbol is known at link
389 // time.
390
391 bool
392 Symbol::final_value_is_known() const
393 {
394   // If we are not generating an executable, then no final values are
395   // known, since they will change at runtime.
396   if (parameters->options().output_is_position_independent()
397       || parameters->options().relocatable())
398     return false;
399
400   // If the symbol is not from an object file, and is not undefined,
401   // then it is defined, and known.
402   if (this->source_ != FROM_OBJECT)
403     {
404       if (this->source_ != IS_UNDEFINED)
405         return true;
406     }
407   else
408     {
409       // If the symbol is from a dynamic object, then the final value
410       // is not known.
411       if (this->object()->is_dynamic())
412         return false;
413
414       // If the symbol is not undefined (it is defined or common),
415       // then the final value is known.
416       if (!this->is_undefined())
417         return true;
418     }
419
420   // If the symbol is undefined, then whether the final value is known
421   // depends on whether we are doing a static link.  If we are doing a
422   // dynamic link, then the final value could be filled in at runtime.
423   // This could reasonably be the case for a weak undefined symbol.
424   return parameters->doing_static_link();
425 }
426
427 // Return the output section where this symbol is defined.
428
429 Output_section*
430 Symbol::output_section() const
431 {
432   switch (this->source_)
433     {
434     case FROM_OBJECT:
435       {
436         unsigned int shndx = this->u_.from_object.shndx;
437         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
438           {
439             gold_assert(!this->u_.from_object.object->is_dynamic());
440             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
441             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
442             return relobj->output_section(shndx);
443           }
444         return NULL;
445       }
446
447     case IN_OUTPUT_DATA:
448       return this->u_.in_output_data.output_data->output_section();
449
450     case IN_OUTPUT_SEGMENT:
451     case IS_CONSTANT:
452     case IS_UNDEFINED:
453       return NULL;
454
455     default:
456       gold_unreachable();
457     }
458 }
459
460 // Set the symbol's output section.  This is used for symbols defined
461 // in scripts.  This should only be called after the symbol table has
462 // been finalized.
463
464 void
465 Symbol::set_output_section(Output_section* os)
466 {
467   switch (this->source_)
468     {
469     case FROM_OBJECT:
470     case IN_OUTPUT_DATA:
471       gold_assert(this->output_section() == os);
472       break;
473     case IS_CONSTANT:
474       this->source_ = IN_OUTPUT_DATA;
475       this->u_.in_output_data.output_data = os;
476       this->u_.in_output_data.offset_is_from_end = false;
477       break;
478     case IN_OUTPUT_SEGMENT:
479     case IS_UNDEFINED:
480     default:
481       gold_unreachable();
482     }
483 }
484
485 // Class Symbol_table.
486
487 Symbol_table::Symbol_table(unsigned int count,
488                            const Version_script_info& version_script)
489   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
490     forwarders_(), commons_(), tls_commons_(), small_commons_(),
491     large_commons_(), forced_locals_(), warnings_(),
492     version_script_(version_script), gc_(NULL), icf_(NULL)
493 {
494   namepool_.reserve(count);
495 }
496
497 Symbol_table::~Symbol_table()
498 {
499 }
500
501 // The hash function.  The key values are Stringpool keys.
502
503 inline size_t
504 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
505 {
506   return key.first ^ key.second;
507 }
508
509 // The symbol table key equality function.  This is called with
510 // Stringpool keys.
511
512 inline bool
513 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
514                                           const Symbol_table_key& k2) const
515 {
516   return k1.first == k2.first && k1.second == k2.second;
517 }
518
519 bool
520 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
521 {
522   return (parameters->options().icf_enabled()
523           && this->icf_->is_section_folded(obj, shndx));
524 }
525
526 // For symbols that have been listed with -u option, add them to the
527 // work list to avoid gc'ing them.
528
529 void 
530 Symbol_table::gc_mark_undef_symbols()
531 {
532   for (options::String_set::const_iterator p =
533          parameters->options().undefined_begin();
534        p != parameters->options().undefined_end();
535        ++p)
536     {
537       const char* name = p->c_str();
538       Symbol* sym = this->lookup(name);
539       gold_assert (sym != NULL);
540       if (sym->source() == Symbol::FROM_OBJECT 
541           && !sym->object()->is_dynamic())
542         {
543           Relobj* obj = static_cast<Relobj*>(sym->object());
544           bool is_ordinary;
545           unsigned int shndx = sym->shndx(&is_ordinary);
546           if (is_ordinary)
547             {
548               gold_assert(this->gc_ != NULL);
549               this->gc_->worklist().push(Section_id(obj, shndx));
550             }
551         }
552     }
553 }
554
555 void
556 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
557 {
558   if (!sym->is_from_dynobj() 
559       && sym->is_externally_visible())
560     {
561       //Add the object and section to the work list.
562       Relobj* obj = static_cast<Relobj*>(sym->object());
563       bool is_ordinary;
564       unsigned int shndx = sym->shndx(&is_ordinary);
565       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
566         {
567           gold_assert(this->gc_!= NULL);
568           this->gc_->worklist().push(Section_id(obj, shndx));
569         }
570     }
571 }
572
573 // When doing garbage collection, keep symbols that have been seen in
574 // dynamic objects.
575 inline void 
576 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
577 {
578   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
579       && !sym->object()->is_dynamic())
580     {
581       Relobj *obj = static_cast<Relobj*>(sym->object()); 
582       bool is_ordinary;
583       unsigned int shndx = sym->shndx(&is_ordinary);
584       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
585         {
586           gold_assert(this->gc_ != NULL);
587           this->gc_->worklist().push(Section_id(obj, shndx));
588         }
589     }
590 }
591
592 // Make TO a symbol which forwards to FROM.
593
594 void
595 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
596 {
597   gold_assert(from != to);
598   gold_assert(!from->is_forwarder() && !to->is_forwarder());
599   this->forwarders_[from] = to;
600   from->set_forwarder();
601 }
602
603 // Resolve the forwards from FROM, returning the real symbol.
604
605 Symbol*
606 Symbol_table::resolve_forwards(const Symbol* from) const
607 {
608   gold_assert(from->is_forwarder());
609   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
610     this->forwarders_.find(from);
611   gold_assert(p != this->forwarders_.end());
612   return p->second;
613 }
614
615 // Look up a symbol by name.
616
617 Symbol*
618 Symbol_table::lookup(const char* name, const char* version) const
619 {
620   Stringpool::Key name_key;
621   name = this->namepool_.find(name, &name_key);
622   if (name == NULL)
623     return NULL;
624
625   Stringpool::Key version_key = 0;
626   if (version != NULL)
627     {
628       version = this->namepool_.find(version, &version_key);
629       if (version == NULL)
630         return NULL;
631     }
632
633   Symbol_table_key key(name_key, version_key);
634   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
635   if (p == this->table_.end())
636     return NULL;
637   return p->second;
638 }
639
640 // Resolve a Symbol with another Symbol.  This is only used in the
641 // unusual case where there are references to both an unversioned
642 // symbol and a symbol with a version, and we then discover that that
643 // version is the default version.  Because this is unusual, we do
644 // this the slow way, by converting back to an ELF symbol.
645
646 template<int size, bool big_endian>
647 void
648 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
649 {
650   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
651   elfcpp::Sym_write<size, big_endian> esym(buf);
652   // We don't bother to set the st_name or the st_shndx field.
653   esym.put_st_value(from->value());
654   esym.put_st_size(from->symsize());
655   esym.put_st_info(from->binding(), from->type());
656   esym.put_st_other(from->visibility(), from->nonvis());
657   bool is_ordinary;
658   unsigned int shndx = from->shndx(&is_ordinary);
659   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
660                 from->version());
661   if (from->in_reg())
662     to->set_in_reg();
663   if (from->in_dyn())
664     to->set_in_dyn();
665   if (parameters->options().gc_sections())
666     this->gc_mark_dyn_syms(to);
667 }
668
669 // Record that a symbol is forced to be local by a version script or
670 // by visibility.
671
672 void
673 Symbol_table::force_local(Symbol* sym)
674 {
675   if (!sym->is_defined() && !sym->is_common())
676     return;
677   if (sym->is_forced_local())
678     {
679       // We already got this one.
680       return;
681     }
682   sym->set_is_forced_local();
683   this->forced_locals_.push_back(sym);
684 }
685
686 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
687 // is only called for undefined symbols, when at least one --wrap
688 // option was used.
689
690 const char*
691 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
692 {
693   // For some targets, we need to ignore a specific character when
694   // wrapping, and add it back later.
695   char prefix = '\0';
696   if (name[0] == parameters->target().wrap_char())
697     {
698       prefix = name[0];
699       ++name;
700     }
701
702   if (parameters->options().is_wrap(name))
703     {
704       // Turn NAME into __wrap_NAME.
705       std::string s;
706       if (prefix != '\0')
707         s += prefix;
708       s += "__wrap_";
709       s += name;
710
711       // This will give us both the old and new name in NAMEPOOL_, but
712       // that is OK.  Only the versions we need will wind up in the
713       // real string table in the output file.
714       return this->namepool_.add(s.c_str(), true, name_key);
715     }
716
717   const char* const real_prefix = "__real_";
718   const size_t real_prefix_length = strlen(real_prefix);
719   if (strncmp(name, real_prefix, real_prefix_length) == 0
720       && parameters->options().is_wrap(name + real_prefix_length))
721     {
722       // Turn __real_NAME into NAME.
723       std::string s;
724       if (prefix != '\0')
725         s += prefix;
726       s += name + real_prefix_length;
727       return this->namepool_.add(s.c_str(), true, name_key);
728     }
729
730   return name;
731 }
732
733 // This is called when we see a symbol NAME/VERSION, and the symbol
734 // already exists in the symbol table, and VERSION is marked as being
735 // the default version.  SYM is the NAME/VERSION symbol we just added.
736 // DEFAULT_IS_NEW is true if this is the first time we have seen the
737 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
738
739 template<int size, bool big_endian>
740 void
741 Symbol_table::define_default_version(Sized_symbol<size>* sym,
742                                      bool default_is_new,
743                                      Symbol_table_type::iterator pdef)
744 {
745   if (default_is_new)
746     {
747       // This is the first time we have seen NAME/NULL.  Make
748       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
749       // version.
750       pdef->second = sym;
751       sym->set_is_default();
752     }
753   else if (pdef->second == sym)
754     {
755       // NAME/NULL already points to NAME/VERSION.  Don't mark the
756       // symbol as the default if it is not already the default.
757     }
758   else
759     {
760       // This is the unfortunate case where we already have entries
761       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
762       // NAME/VERSION where VERSION is the default version.  We have
763       // already resolved this new symbol with the existing
764       // NAME/VERSION symbol.
765
766       // It's possible that NAME/NULL and NAME/VERSION are both
767       // defined in regular objects.  This can only happen if one
768       // object file defines foo and another defines foo@@ver.  This
769       // is somewhat obscure, but we call it a multiple definition
770       // error.
771
772       // It's possible that NAME/NULL actually has a version, in which
773       // case it won't be the same as VERSION.  This happens with
774       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
775       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
776       // then see an unadorned t2_2 in an object file and give it
777       // version VER1 from the version script.  This looks like a
778       // default definition for VER1, so it looks like we should merge
779       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
780       // not obvious that this is an error, either.  So we just punt.
781
782       // If one of the symbols has non-default visibility, and the
783       // other is defined in a shared object, then they are different
784       // symbols.
785
786       // Otherwise, we just resolve the symbols as though they were
787       // the same.
788
789       if (pdef->second->version() != NULL)
790         gold_assert(pdef->second->version() != sym->version());
791       else if (sym->visibility() != elfcpp::STV_DEFAULT
792                && pdef->second->is_from_dynobj())
793         ;
794       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
795                && sym->is_from_dynobj())
796         ;
797       else
798         {
799           const Sized_symbol<size>* symdef;
800           symdef = this->get_sized_symbol<size>(pdef->second);
801           Symbol_table::resolve<size, big_endian>(sym, symdef);
802           this->make_forwarder(pdef->second, sym);
803           pdef->second = sym;
804           sym->set_is_default();
805         }
806     }
807 }
808
809 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
810 // name and VERSION is the version; both are canonicalized.  DEF is
811 // whether this is the default version.  ST_SHNDX is the symbol's
812 // section index; IS_ORDINARY is whether this is a normal section
813 // rather than a special code.
814
815 // If IS_DEFAULT_VERSION is true, then this is the definition of a
816 // default version of a symbol.  That means that any lookup of
817 // NAME/NULL and any lookup of NAME/VERSION should always return the
818 // same symbol.  This is obvious for references, but in particular we
819 // want to do this for definitions: overriding NAME/NULL should also
820 // override NAME/VERSION.  If we don't do that, it would be very hard
821 // to override functions in a shared library which uses versioning.
822
823 // We implement this by simply making both entries in the hash table
824 // point to the same Symbol structure.  That is easy enough if this is
825 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
826 // that we have seen both already, in which case they will both have
827 // independent entries in the symbol table.  We can't simply change
828 // the symbol table entry, because we have pointers to the entries
829 // attached to the object files.  So we mark the entry attached to the
830 // object file as a forwarder, and record it in the forwarders_ map.
831 // Note that entries in the hash table will never be marked as
832 // forwarders.
833 //
834 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
835 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
836 // for a special section code.  ST_SHNDX may be modified if the symbol
837 // is defined in a section being discarded.
838
839 template<int size, bool big_endian>
840 Sized_symbol<size>*
841 Symbol_table::add_from_object(Object* object,
842                               const char *name,
843                               Stringpool::Key name_key,
844                               const char *version,
845                               Stringpool::Key version_key,
846                               bool is_default_version,
847                               const elfcpp::Sym<size, big_endian>& sym,
848                               unsigned int st_shndx,
849                               bool is_ordinary,
850                               unsigned int orig_st_shndx)
851 {
852   // Print a message if this symbol is being traced.
853   if (parameters->options().is_trace_symbol(name))
854     {
855       if (orig_st_shndx == elfcpp::SHN_UNDEF)
856         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
857       else
858         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
859     }
860
861   // For an undefined symbol, we may need to adjust the name using
862   // --wrap.
863   if (orig_st_shndx == elfcpp::SHN_UNDEF
864       && parameters->options().any_wrap())
865     {
866       const char* wrap_name = this->wrap_symbol(name, &name_key);
867       if (wrap_name != name)
868         {
869           // If we see a reference to malloc with version GLIBC_2.0,
870           // and we turn it into a reference to __wrap_malloc, then we
871           // discard the version number.  Otherwise the user would be
872           // required to specify the correct version for
873           // __wrap_malloc.
874           version = NULL;
875           version_key = 0;
876           name = wrap_name;
877         }
878     }
879
880   Symbol* const snull = NULL;
881   std::pair<typename Symbol_table_type::iterator, bool> ins =
882     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
883                                        snull));
884
885   std::pair<typename Symbol_table_type::iterator, bool> insdefault =
886     std::make_pair(this->table_.end(), false);
887   if (is_default_version)
888     {
889       const Stringpool::Key vnull_key = 0;
890       insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
891                                                                      vnull_key),
892                                                       snull));
893     }
894
895   // ins.first: an iterator, which is a pointer to a pair.
896   // ins.first->first: the key (a pair of name and version).
897   // ins.first->second: the value (Symbol*).
898   // ins.second: true if new entry was inserted, false if not.
899
900   Sized_symbol<size>* ret;
901   bool was_undefined;
902   bool was_common;
903   if (!ins.second)
904     {
905       // We already have an entry for NAME/VERSION.
906       ret = this->get_sized_symbol<size>(ins.first->second);
907       gold_assert(ret != NULL);
908
909       was_undefined = ret->is_undefined();
910       was_common = ret->is_common();
911
912       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
913                     version);
914       if (parameters->options().gc_sections())
915         this->gc_mark_dyn_syms(ret);
916
917       if (is_default_version)
918         this->define_default_version<size, big_endian>(ret, insdefault.second,
919                                                        insdefault.first);
920     }
921   else
922     {
923       // This is the first time we have seen NAME/VERSION.
924       gold_assert(ins.first->second == NULL);
925
926       if (is_default_version && !insdefault.second)
927         {
928           // We already have an entry for NAME/NULL.  If we override
929           // it, then change it to NAME/VERSION.
930           ret = this->get_sized_symbol<size>(insdefault.first->second);
931
932           was_undefined = ret->is_undefined();
933           was_common = ret->is_common();
934
935           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
936                         version);
937           if (parameters->options().gc_sections())
938             this->gc_mark_dyn_syms(ret);
939           ins.first->second = ret;
940         }
941       else
942         {
943           was_undefined = false;
944           was_common = false;
945
946           Sized_target<size, big_endian>* target =
947             parameters->sized_target<size, big_endian>();
948           if (!target->has_make_symbol())
949             ret = new Sized_symbol<size>();
950           else
951             {
952               ret = target->make_symbol();
953               if (ret == NULL)
954                 {
955                   // This means that we don't want a symbol table
956                   // entry after all.
957                   if (!is_default_version)
958                     this->table_.erase(ins.first);
959                   else
960                     {
961                       this->table_.erase(insdefault.first);
962                       // Inserting INSDEFAULT invalidated INS.
963                       this->table_.erase(std::make_pair(name_key,
964                                                         version_key));
965                     }
966                   return NULL;
967                 }
968             }
969
970           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
971
972           ins.first->second = ret;
973           if (is_default_version)
974             {
975               // This is the first time we have seen NAME/NULL.  Point
976               // it at the new entry for NAME/VERSION.
977               gold_assert(insdefault.second);
978               insdefault.first->second = ret;
979             }
980         }
981
982       if (is_default_version)
983         ret->set_is_default();
984     }
985
986   // Record every time we see a new undefined symbol, to speed up
987   // archive groups.
988   if (!was_undefined && ret->is_undefined())
989     ++this->saw_undefined_;
990
991   // Keep track of common symbols, to speed up common symbol
992   // allocation.
993   if (!was_common && ret->is_common())
994     {
995       if (ret->type() == elfcpp::STT_TLS)
996         this->tls_commons_.push_back(ret);
997       else if (!is_ordinary
998                && st_shndx == parameters->target().small_common_shndx())
999         this->small_commons_.push_back(ret);
1000       else if (!is_ordinary
1001                && st_shndx == parameters->target().large_common_shndx())
1002         this->large_commons_.push_back(ret);
1003       else
1004         this->commons_.push_back(ret);
1005     }
1006
1007   // If we're not doing a relocatable link, then any symbol with
1008   // hidden or internal visibility is local.
1009   if ((ret->visibility() == elfcpp::STV_HIDDEN
1010        || ret->visibility() == elfcpp::STV_INTERNAL)
1011       && (ret->binding() == elfcpp::STB_GLOBAL
1012           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1013           || ret->binding() == elfcpp::STB_WEAK)
1014       && !parameters->options().relocatable())
1015     this->force_local(ret);
1016
1017   return ret;
1018 }
1019
1020 // Add all the symbols in a relocatable object to the hash table.
1021
1022 template<int size, bool big_endian>
1023 void
1024 Symbol_table::add_from_relobj(
1025     Sized_relobj<size, big_endian>* relobj,
1026     const unsigned char* syms,
1027     size_t count,
1028     size_t symndx_offset,
1029     const char* sym_names,
1030     size_t sym_name_size,
1031     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1032     size_t *defined)
1033 {
1034   *defined = 0;
1035
1036   gold_assert(size == parameters->target().get_size());
1037
1038   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1039
1040   const bool just_symbols = relobj->just_symbols();
1041
1042   const unsigned char* p = syms;
1043   for (size_t i = 0; i < count; ++i, p += sym_size)
1044     {
1045       (*sympointers)[i] = NULL;
1046
1047       elfcpp::Sym<size, big_endian> sym(p);
1048
1049       unsigned int st_name = sym.get_st_name();
1050       if (st_name >= sym_name_size)
1051         {
1052           relobj->error(_("bad global symbol name offset %u at %zu"),
1053                         st_name, i);
1054           continue;
1055         }
1056
1057       const char* name = sym_names + st_name;
1058
1059       bool is_ordinary;
1060       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1061                                                        sym.get_st_shndx(),
1062                                                        &is_ordinary);
1063       unsigned int orig_st_shndx = st_shndx;
1064       if (!is_ordinary)
1065         orig_st_shndx = elfcpp::SHN_UNDEF;
1066
1067       if (st_shndx != elfcpp::SHN_UNDEF)
1068         ++*defined;
1069
1070       // A symbol defined in a section which we are not including must
1071       // be treated as an undefined symbol.
1072       bool is_defined_in_discarded_section = false;
1073       if (st_shndx != elfcpp::SHN_UNDEF
1074           && is_ordinary
1075           && !relobj->is_section_included(st_shndx))
1076         {
1077           st_shndx = elfcpp::SHN_UNDEF;
1078           is_defined_in_discarded_section = true;
1079         }
1080
1081       // In an object file, an '@' in the name separates the symbol
1082       // name from the version name.  If there are two '@' characters,
1083       // this is the default version.
1084       const char* ver = strchr(name, '@');
1085       Stringpool::Key ver_key = 0;
1086       int namelen = 0;
1087       // IS_DEFAULT_VERSION: is the version default?
1088       // IS_FORCED_LOCAL: is the symbol forced local?
1089       bool is_default_version = false;
1090       bool is_forced_local = false;
1091
1092       if (ver != NULL)
1093         {
1094           // The symbol name is of the form foo@VERSION or foo@@VERSION
1095           namelen = ver - name;
1096           ++ver;
1097           if (*ver == '@')
1098             {
1099               is_default_version = true;
1100               ++ver;
1101             }
1102           ver = this->namepool_.add(ver, true, &ver_key);
1103         }
1104       // We don't want to assign a version to an undefined symbol,
1105       // even if it is listed in the version script.  FIXME: What
1106       // about a common symbol?
1107       else
1108         {
1109           namelen = strlen(name);
1110           if (!this->version_script_.empty()
1111               && st_shndx != elfcpp::SHN_UNDEF)
1112             {
1113               // The symbol name did not have a version, but the
1114               // version script may assign a version anyway.
1115               std::string version;
1116               bool is_global;
1117               if (this->version_script_.get_symbol_version(name, &version,
1118                                                            &is_global))
1119                 {
1120                   if (!is_global)
1121                     is_forced_local = true;
1122                   else if (!version.empty())
1123                     {
1124                       ver = this->namepool_.add_with_length(version.c_str(),
1125                                                             version.length(),
1126                                                             true,
1127                                                             &ver_key);
1128                       is_default_version = true;
1129                     }
1130                 }
1131             }
1132         }
1133
1134       elfcpp::Sym<size, big_endian>* psym = &sym;
1135       unsigned char symbuf[sym_size];
1136       elfcpp::Sym<size, big_endian> sym2(symbuf);
1137       if (just_symbols)
1138         {
1139           memcpy(symbuf, p, sym_size);
1140           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1141           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1142             {
1143               // Symbol values in object files are section relative.
1144               // This is normally what we want, but since here we are
1145               // converting the symbol to absolute we need to add the
1146               // section address.  The section address in an object
1147               // file is normally zero, but people can use a linker
1148               // script to change it.
1149               sw.put_st_value(sym.get_st_value()
1150                               + relobj->section_address(orig_st_shndx));
1151             }
1152           st_shndx = elfcpp::SHN_ABS;
1153           is_ordinary = false;
1154           psym = &sym2;
1155         }
1156
1157       // Fix up visibility if object has no-export set.
1158       if (relobj->no_export()
1159           && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1160         {
1161           // We may have copied symbol already above.
1162           if (psym != &sym2)
1163             {
1164               memcpy(symbuf, p, sym_size);
1165               psym = &sym2;
1166             }
1167
1168           elfcpp::STV visibility = sym2.get_st_visibility();
1169           if (visibility == elfcpp::STV_DEFAULT
1170               || visibility == elfcpp::STV_PROTECTED)
1171             {
1172               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1173               unsigned char nonvis = sym2.get_st_nonvis();
1174               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1175             }
1176         }
1177
1178       Stringpool::Key name_key;
1179       name = this->namepool_.add_with_length(name, namelen, true,
1180                                              &name_key);
1181
1182       Sized_symbol<size>* res;
1183       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1184                                   is_default_version, *psym, st_shndx,
1185                                   is_ordinary, orig_st_shndx);
1186       
1187       // If building a shared library using garbage collection, do not 
1188       // treat externally visible symbols as garbage.
1189       if (parameters->options().gc_sections() 
1190           && parameters->options().shared())
1191         this->gc_mark_symbol_for_shlib(res);
1192
1193       if (is_forced_local)
1194         this->force_local(res);
1195
1196       if (is_defined_in_discarded_section)
1197         res->set_is_defined_in_discarded_section();
1198
1199       (*sympointers)[i] = res;
1200     }
1201 }
1202
1203 // Add a symbol from a plugin-claimed file.
1204
1205 template<int size, bool big_endian>
1206 Symbol*
1207 Symbol_table::add_from_pluginobj(
1208     Sized_pluginobj<size, big_endian>* obj,
1209     const char* name,
1210     const char* ver,
1211     elfcpp::Sym<size, big_endian>* sym)
1212 {
1213   unsigned int st_shndx = sym->get_st_shndx();
1214   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1215
1216   Stringpool::Key ver_key = 0;
1217   bool is_default_version = false;
1218   bool is_forced_local = false;
1219
1220   if (ver != NULL)
1221     {
1222       ver = this->namepool_.add(ver, true, &ver_key);
1223     }
1224   // We don't want to assign a version to an undefined symbol,
1225   // even if it is listed in the version script.  FIXME: What
1226   // about a common symbol?
1227   else
1228     {
1229       if (!this->version_script_.empty()
1230           && st_shndx != elfcpp::SHN_UNDEF)
1231         {
1232           // The symbol name did not have a version, but the
1233           // version script may assign a version anyway.
1234           std::string version;
1235           bool is_global;
1236           if (this->version_script_.get_symbol_version(name, &version,
1237                                                        &is_global))
1238             {
1239               if (!is_global)
1240                 is_forced_local = true;
1241               else if (!version.empty())
1242                 {
1243                   ver = this->namepool_.add_with_length(version.c_str(),
1244                                                         version.length(),
1245                                                         true,
1246                                                         &ver_key);
1247                   is_default_version = true;
1248                 }
1249             }
1250         }
1251     }
1252
1253   Stringpool::Key name_key;
1254   name = this->namepool_.add(name, true, &name_key);
1255
1256   Sized_symbol<size>* res;
1257   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1258                               is_default_version, *sym, st_shndx,
1259                               is_ordinary, st_shndx);
1260
1261   if (is_forced_local)
1262     this->force_local(res);
1263
1264   return res;
1265 }
1266
1267 // Add all the symbols in a dynamic object to the hash table.
1268
1269 template<int size, bool big_endian>
1270 void
1271 Symbol_table::add_from_dynobj(
1272     Sized_dynobj<size, big_endian>* dynobj,
1273     const unsigned char* syms,
1274     size_t count,
1275     const char* sym_names,
1276     size_t sym_name_size,
1277     const unsigned char* versym,
1278     size_t versym_size,
1279     const std::vector<const char*>* version_map,
1280     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1281     size_t* defined)
1282 {
1283   *defined = 0;
1284
1285   gold_assert(size == parameters->target().get_size());
1286
1287   if (dynobj->just_symbols())
1288     {
1289       gold_error(_("--just-symbols does not make sense with a shared object"));
1290       return;
1291     }
1292
1293   if (versym != NULL && versym_size / 2 < count)
1294     {
1295       dynobj->error(_("too few symbol versions"));
1296       return;
1297     }
1298
1299   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1300
1301   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1302   // weak aliases.  This is necessary because if the dynamic object
1303   // provides the same variable under two names, one of which is a
1304   // weak definition, and the regular object refers to the weak
1305   // definition, we have to put both the weak definition and the
1306   // strong definition into the dynamic symbol table.  Given a weak
1307   // definition, the only way that we can find the corresponding
1308   // strong definition, if any, is to search the symbol table.
1309   std::vector<Sized_symbol<size>*> object_symbols;
1310
1311   const unsigned char* p = syms;
1312   const unsigned char* vs = versym;
1313   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1314     {
1315       elfcpp::Sym<size, big_endian> sym(p);
1316
1317       if (sympointers != NULL)
1318         (*sympointers)[i] = NULL;
1319
1320       // Ignore symbols with local binding or that have
1321       // internal or hidden visibility.
1322       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1323           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1324           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1325         continue;
1326
1327       // A protected symbol in a shared library must be treated as a
1328       // normal symbol when viewed from outside the shared library.
1329       // Implement this by overriding the visibility here.
1330       elfcpp::Sym<size, big_endian>* psym = &sym;
1331       unsigned char symbuf[sym_size];
1332       elfcpp::Sym<size, big_endian> sym2(symbuf);
1333       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1334         {
1335           memcpy(symbuf, p, sym_size);
1336           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1337           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1338           psym = &sym2;
1339         }
1340
1341       unsigned int st_name = psym->get_st_name();
1342       if (st_name >= sym_name_size)
1343         {
1344           dynobj->error(_("bad symbol name offset %u at %zu"),
1345                         st_name, i);
1346           continue;
1347         }
1348
1349       const char* name = sym_names + st_name;
1350
1351       bool is_ordinary;
1352       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1353                                                        &is_ordinary);
1354
1355       if (st_shndx != elfcpp::SHN_UNDEF)
1356         ++*defined;
1357
1358       Sized_symbol<size>* res;
1359
1360       if (versym == NULL)
1361         {
1362           Stringpool::Key name_key;
1363           name = this->namepool_.add(name, true, &name_key);
1364           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1365                                       false, *psym, st_shndx, is_ordinary,
1366                                       st_shndx);
1367         }
1368       else
1369         {
1370           // Read the version information.
1371
1372           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1373
1374           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1375           v &= elfcpp::VERSYM_VERSION;
1376
1377           // The Sun documentation says that V can be VER_NDX_LOCAL,
1378           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1379           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1380           // The old GNU linker will happily generate VER_NDX_LOCAL
1381           // for an undefined symbol.  I don't know what the Sun
1382           // linker will generate.
1383
1384           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1385               && st_shndx != elfcpp::SHN_UNDEF)
1386             {
1387               // This symbol should not be visible outside the object.
1388               continue;
1389             }
1390
1391           // At this point we are definitely going to add this symbol.
1392           Stringpool::Key name_key;
1393           name = this->namepool_.add(name, true, &name_key);
1394
1395           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1396               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1397             {
1398               // This symbol does not have a version.
1399               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1400                                           false, *psym, st_shndx, is_ordinary,
1401                                           st_shndx);
1402             }
1403           else
1404             {
1405               if (v >= version_map->size())
1406                 {
1407                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1408                                 i, v);
1409                   continue;
1410                 }
1411
1412               const char* version = (*version_map)[v];
1413               if (version == NULL)
1414                 {
1415                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1416                                 i, v);
1417                   continue;
1418                 }
1419
1420               Stringpool::Key version_key;
1421               version = this->namepool_.add(version, true, &version_key);
1422
1423               // If this is an absolute symbol, and the version name
1424               // and symbol name are the same, then this is the
1425               // version definition symbol.  These symbols exist to
1426               // support using -u to pull in particular versions.  We
1427               // do not want to record a version for them.
1428               if (st_shndx == elfcpp::SHN_ABS
1429                   && !is_ordinary
1430                   && name_key == version_key)
1431                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1432                                             false, *psym, st_shndx, is_ordinary,
1433                                             st_shndx);
1434               else
1435                 {
1436                   const bool is_default_version =
1437                     !hidden && st_shndx != elfcpp::SHN_UNDEF;
1438                   res = this->add_from_object(dynobj, name, name_key, version,
1439                                               version_key, is_default_version,
1440                                               *psym, st_shndx,
1441                                               is_ordinary, st_shndx);
1442                 }
1443             }
1444         }
1445
1446       // Note that it is possible that RES was overridden by an
1447       // earlier object, in which case it can't be aliased here.
1448       if (st_shndx != elfcpp::SHN_UNDEF
1449           && is_ordinary
1450           && psym->get_st_type() == elfcpp::STT_OBJECT
1451           && res->source() == Symbol::FROM_OBJECT
1452           && res->object() == dynobj)
1453         object_symbols.push_back(res);
1454
1455       if (sympointers != NULL)
1456         (*sympointers)[i] = res;
1457     }
1458
1459   this->record_weak_aliases(&object_symbols);
1460 }
1461
1462 // This is used to sort weak aliases.  We sort them first by section
1463 // index, then by offset, then by weak ahead of strong.
1464
1465 template<int size>
1466 class Weak_alias_sorter
1467 {
1468  public:
1469   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1470 };
1471
1472 template<int size>
1473 bool
1474 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1475                                     const Sized_symbol<size>* s2) const
1476 {
1477   bool is_ordinary;
1478   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1479   gold_assert(is_ordinary);
1480   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1481   gold_assert(is_ordinary);
1482   if (s1_shndx != s2_shndx)
1483     return s1_shndx < s2_shndx;
1484
1485   if (s1->value() != s2->value())
1486     return s1->value() < s2->value();
1487   if (s1->binding() != s2->binding())
1488     {
1489       if (s1->binding() == elfcpp::STB_WEAK)
1490         return true;
1491       if (s2->binding() == elfcpp::STB_WEAK)
1492         return false;
1493     }
1494   return std::string(s1->name()) < std::string(s2->name());
1495 }
1496
1497 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1498 // for any weak aliases, and record them so that if we add the weak
1499 // alias to the dynamic symbol table, we also add the corresponding
1500 // strong symbol.
1501
1502 template<int size>
1503 void
1504 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1505 {
1506   // Sort the vector by section index, then by offset, then by weak
1507   // ahead of strong.
1508   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1509
1510   // Walk through the vector.  For each weak definition, record
1511   // aliases.
1512   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1513          symbols->begin();
1514        p != symbols->end();
1515        ++p)
1516     {
1517       if ((*p)->binding() != elfcpp::STB_WEAK)
1518         continue;
1519
1520       // Build a circular list of weak aliases.  Each symbol points to
1521       // the next one in the circular list.
1522
1523       Sized_symbol<size>* from_sym = *p;
1524       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1525       for (q = p + 1; q != symbols->end(); ++q)
1526         {
1527           bool dummy;
1528           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1529               || (*q)->value() != from_sym->value())
1530             break;
1531
1532           this->weak_aliases_[from_sym] = *q;
1533           from_sym->set_has_alias();
1534           from_sym = *q;
1535         }
1536
1537       if (from_sym != *p)
1538         {
1539           this->weak_aliases_[from_sym] = *p;
1540           from_sym->set_has_alias();
1541         }
1542
1543       p = q - 1;
1544     }
1545 }
1546
1547 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1548 // true, then only create the symbol if there is a reference to it.
1549 // If this does not return NULL, it sets *POLDSYM to the existing
1550 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1551 // resolve the newly created symbol to the old one.  This
1552 // canonicalizes *PNAME and *PVERSION.
1553
1554 template<int size, bool big_endian>
1555 Sized_symbol<size>*
1556 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1557                                     bool only_if_ref,
1558                                     Sized_symbol<size>** poldsym,
1559                                     bool *resolve_oldsym)
1560 {
1561   *resolve_oldsym = false;
1562
1563   // If the caller didn't give us a version, see if we get one from
1564   // the version script.
1565   std::string v;
1566   bool is_default_version = false;
1567   if (*pversion == NULL)
1568     {
1569       bool is_global;
1570       if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1571         {
1572           if (is_global && !v.empty())
1573             {
1574               *pversion = v.c_str();
1575               // If we get the version from a version script, then we
1576               // are also the default version.
1577               is_default_version = true;
1578             }
1579         }
1580     }
1581
1582   Symbol* oldsym;
1583   Sized_symbol<size>* sym;
1584
1585   bool add_to_table = false;
1586   typename Symbol_table_type::iterator add_loc = this->table_.end();
1587   bool add_def_to_table = false;
1588   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1589
1590   if (only_if_ref)
1591     {
1592       oldsym = this->lookup(*pname, *pversion);
1593       if (oldsym == NULL && is_default_version)
1594         oldsym = this->lookup(*pname, NULL);
1595       if (oldsym == NULL || !oldsym->is_undefined())
1596         return NULL;
1597
1598       *pname = oldsym->name();
1599       if (!is_default_version)
1600         *pversion = oldsym->version();
1601     }
1602   else
1603     {
1604       // Canonicalize NAME and VERSION.
1605       Stringpool::Key name_key;
1606       *pname = this->namepool_.add(*pname, true, &name_key);
1607
1608       Stringpool::Key version_key = 0;
1609       if (*pversion != NULL)
1610         *pversion = this->namepool_.add(*pversion, true, &version_key);
1611
1612       Symbol* const snull = NULL;
1613       std::pair<typename Symbol_table_type::iterator, bool> ins =
1614         this->table_.insert(std::make_pair(std::make_pair(name_key,
1615                                                           version_key),
1616                                            snull));
1617
1618       std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1619         std::make_pair(this->table_.end(), false);
1620       if (is_default_version)
1621         {
1622           const Stringpool::Key vnull = 0;
1623           insdefault =
1624             this->table_.insert(std::make_pair(std::make_pair(name_key,
1625                                                               vnull),
1626                                                snull));
1627         }
1628
1629       if (!ins.second)
1630         {
1631           // We already have a symbol table entry for NAME/VERSION.
1632           oldsym = ins.first->second;
1633           gold_assert(oldsym != NULL);
1634
1635           if (is_default_version)
1636             {
1637               Sized_symbol<size>* soldsym =
1638                 this->get_sized_symbol<size>(oldsym);
1639               this->define_default_version<size, big_endian>(soldsym,
1640                                                              insdefault.second,
1641                                                              insdefault.first);
1642             }
1643         }
1644       else
1645         {
1646           // We haven't seen this symbol before.
1647           gold_assert(ins.first->second == NULL);
1648
1649           add_to_table = true;
1650           add_loc = ins.first;
1651
1652           if (is_default_version && !insdefault.second)
1653             {
1654               // We are adding NAME/VERSION, and it is the default
1655               // version.  We already have an entry for NAME/NULL.
1656               oldsym = insdefault.first->second;
1657               *resolve_oldsym = true;
1658             }
1659           else
1660             {
1661               oldsym = NULL;
1662
1663               if (is_default_version)
1664                 {
1665                   add_def_to_table = true;
1666                   add_def_loc = insdefault.first;
1667                 }
1668             }
1669         }
1670     }
1671
1672   const Target& target = parameters->target();
1673   if (!target.has_make_symbol())
1674     sym = new Sized_symbol<size>();
1675   else
1676     {
1677       Sized_target<size, big_endian>* sized_target =
1678         parameters->sized_target<size, big_endian>();
1679       sym = sized_target->make_symbol();
1680       if (sym == NULL)
1681         return NULL;
1682     }
1683
1684   if (add_to_table)
1685     add_loc->second = sym;
1686   else
1687     gold_assert(oldsym != NULL);
1688
1689   if (add_def_to_table)
1690     add_def_loc->second = sym;
1691
1692   *poldsym = this->get_sized_symbol<size>(oldsym);
1693
1694   return sym;
1695 }
1696
1697 // Define a symbol based on an Output_data.
1698
1699 Symbol*
1700 Symbol_table::define_in_output_data(const char* name,
1701                                     const char* version,
1702                                     Defined defined,
1703                                     Output_data* od,
1704                                     uint64_t value,
1705                                     uint64_t symsize,
1706                                     elfcpp::STT type,
1707                                     elfcpp::STB binding,
1708                                     elfcpp::STV visibility,
1709                                     unsigned char nonvis,
1710                                     bool offset_is_from_end,
1711                                     bool only_if_ref)
1712 {
1713   if (parameters->target().get_size() == 32)
1714     {
1715 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1716       return this->do_define_in_output_data<32>(name, version, defined, od,
1717                                                 value, symsize, type, binding,
1718                                                 visibility, nonvis,
1719                                                 offset_is_from_end,
1720                                                 only_if_ref);
1721 #else
1722       gold_unreachable();
1723 #endif
1724     }
1725   else if (parameters->target().get_size() == 64)
1726     {
1727 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1728       return this->do_define_in_output_data<64>(name, version, defined, od,
1729                                                 value, symsize, type, binding,
1730                                                 visibility, nonvis,
1731                                                 offset_is_from_end,
1732                                                 only_if_ref);
1733 #else
1734       gold_unreachable();
1735 #endif
1736     }
1737   else
1738     gold_unreachable();
1739 }
1740
1741 // Define a symbol in an Output_data, sized version.
1742
1743 template<int size>
1744 Sized_symbol<size>*
1745 Symbol_table::do_define_in_output_data(
1746     const char* name,
1747     const char* version,
1748     Defined defined,
1749     Output_data* od,
1750     typename elfcpp::Elf_types<size>::Elf_Addr value,
1751     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1752     elfcpp::STT type,
1753     elfcpp::STB binding,
1754     elfcpp::STV visibility,
1755     unsigned char nonvis,
1756     bool offset_is_from_end,
1757     bool only_if_ref)
1758 {
1759   Sized_symbol<size>* sym;
1760   Sized_symbol<size>* oldsym;
1761   bool resolve_oldsym;
1762
1763   if (parameters->target().is_big_endian())
1764     {
1765 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1766       sym = this->define_special_symbol<size, true>(&name, &version,
1767                                                     only_if_ref, &oldsym,
1768                                                     &resolve_oldsym);
1769 #else
1770       gold_unreachable();
1771 #endif
1772     }
1773   else
1774     {
1775 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1776       sym = this->define_special_symbol<size, false>(&name, &version,
1777                                                      only_if_ref, &oldsym,
1778                                                      &resolve_oldsym);
1779 #else
1780       gold_unreachable();
1781 #endif
1782     }
1783
1784   if (sym == NULL)
1785     return NULL;
1786
1787   sym->init_output_data(name, version, od, value, symsize, type, binding,
1788                         visibility, nonvis, offset_is_from_end);
1789
1790   if (oldsym == NULL)
1791     {
1792       if (binding == elfcpp::STB_LOCAL
1793           || this->version_script_.symbol_is_local(name))
1794         this->force_local(sym);
1795       else if (version != NULL)
1796         sym->set_is_default();
1797       return sym;
1798     }
1799
1800   if (Symbol_table::should_override_with_special(oldsym, defined))
1801     this->override_with_special(oldsym, sym);
1802
1803   if (resolve_oldsym)
1804     return sym;
1805   else
1806     {
1807       delete sym;
1808       return oldsym;
1809     }
1810 }
1811
1812 // Define a symbol based on an Output_segment.
1813
1814 Symbol*
1815 Symbol_table::define_in_output_segment(const char* name,
1816                                        const char* version,
1817                                        Defined defined,
1818                                        Output_segment* os,
1819                                        uint64_t value,
1820                                        uint64_t symsize,
1821                                        elfcpp::STT type,
1822                                        elfcpp::STB binding,
1823                                        elfcpp::STV visibility,
1824                                        unsigned char nonvis,
1825                                        Symbol::Segment_offset_base offset_base,
1826                                        bool only_if_ref)
1827 {
1828   if (parameters->target().get_size() == 32)
1829     {
1830 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1831       return this->do_define_in_output_segment<32>(name, version, defined, os,
1832                                                    value, symsize, type,
1833                                                    binding, visibility, nonvis,
1834                                                    offset_base, only_if_ref);
1835 #else
1836       gold_unreachable();
1837 #endif
1838     }
1839   else if (parameters->target().get_size() == 64)
1840     {
1841 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1842       return this->do_define_in_output_segment<64>(name, version, defined, os,
1843                                                    value, symsize, type,
1844                                                    binding, visibility, nonvis,
1845                                                    offset_base, only_if_ref);
1846 #else
1847       gold_unreachable();
1848 #endif
1849     }
1850   else
1851     gold_unreachable();
1852 }
1853
1854 // Define a symbol in an Output_segment, sized version.
1855
1856 template<int size>
1857 Sized_symbol<size>*
1858 Symbol_table::do_define_in_output_segment(
1859     const char* name,
1860     const char* version,
1861     Defined defined,
1862     Output_segment* os,
1863     typename elfcpp::Elf_types<size>::Elf_Addr value,
1864     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1865     elfcpp::STT type,
1866     elfcpp::STB binding,
1867     elfcpp::STV visibility,
1868     unsigned char nonvis,
1869     Symbol::Segment_offset_base offset_base,
1870     bool only_if_ref)
1871 {
1872   Sized_symbol<size>* sym;
1873   Sized_symbol<size>* oldsym;
1874   bool resolve_oldsym;
1875
1876   if (parameters->target().is_big_endian())
1877     {
1878 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1879       sym = this->define_special_symbol<size, true>(&name, &version,
1880                                                     only_if_ref, &oldsym,
1881                                                     &resolve_oldsym);
1882 #else
1883       gold_unreachable();
1884 #endif
1885     }
1886   else
1887     {
1888 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1889       sym = this->define_special_symbol<size, false>(&name, &version,
1890                                                      only_if_ref, &oldsym,
1891                                                      &resolve_oldsym);
1892 #else
1893       gold_unreachable();
1894 #endif
1895     }
1896
1897   if (sym == NULL)
1898     return NULL;
1899
1900   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1901                            visibility, nonvis, offset_base);
1902
1903   if (oldsym == NULL)
1904     {
1905       if (binding == elfcpp::STB_LOCAL
1906           || this->version_script_.symbol_is_local(name))
1907         this->force_local(sym);
1908       else if (version != NULL)
1909         sym->set_is_default();
1910       return sym;
1911     }
1912
1913   if (Symbol_table::should_override_with_special(oldsym, defined))
1914     this->override_with_special(oldsym, sym);
1915
1916   if (resolve_oldsym)
1917     return sym;
1918   else
1919     {
1920       delete sym;
1921       return oldsym;
1922     }
1923 }
1924
1925 // Define a special symbol with a constant value.  It is a multiple
1926 // definition error if this symbol is already defined.
1927
1928 Symbol*
1929 Symbol_table::define_as_constant(const char* name,
1930                                  const char* version,
1931                                  Defined defined,
1932                                  uint64_t value,
1933                                  uint64_t symsize,
1934                                  elfcpp::STT type,
1935                                  elfcpp::STB binding,
1936                                  elfcpp::STV visibility,
1937                                  unsigned char nonvis,
1938                                  bool only_if_ref,
1939                                  bool force_override)
1940 {
1941   if (parameters->target().get_size() == 32)
1942     {
1943 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1944       return this->do_define_as_constant<32>(name, version, defined, value,
1945                                              symsize, type, binding,
1946                                              visibility, nonvis, only_if_ref,
1947                                              force_override);
1948 #else
1949       gold_unreachable();
1950 #endif
1951     }
1952   else if (parameters->target().get_size() == 64)
1953     {
1954 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1955       return this->do_define_as_constant<64>(name, version, defined, value,
1956                                              symsize, type, binding,
1957                                              visibility, nonvis, only_if_ref,
1958                                              force_override);
1959 #else
1960       gold_unreachable();
1961 #endif
1962     }
1963   else
1964     gold_unreachable();
1965 }
1966
1967 // Define a symbol as a constant, sized version.
1968
1969 template<int size>
1970 Sized_symbol<size>*
1971 Symbol_table::do_define_as_constant(
1972     const char* name,
1973     const char* version,
1974     Defined defined,
1975     typename elfcpp::Elf_types<size>::Elf_Addr value,
1976     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1977     elfcpp::STT type,
1978     elfcpp::STB binding,
1979     elfcpp::STV visibility,
1980     unsigned char nonvis,
1981     bool only_if_ref,
1982     bool force_override)
1983 {
1984   Sized_symbol<size>* sym;
1985   Sized_symbol<size>* oldsym;
1986   bool resolve_oldsym;
1987
1988   if (parameters->target().is_big_endian())
1989     {
1990 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1991       sym = this->define_special_symbol<size, true>(&name, &version,
1992                                                     only_if_ref, &oldsym,
1993                                                     &resolve_oldsym);
1994 #else
1995       gold_unreachable();
1996 #endif
1997     }
1998   else
1999     {
2000 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2001       sym = this->define_special_symbol<size, false>(&name, &version,
2002                                                      only_if_ref, &oldsym,
2003                                                      &resolve_oldsym);
2004 #else
2005       gold_unreachable();
2006 #endif
2007     }
2008
2009   if (sym == NULL)
2010     return NULL;
2011
2012   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2013                      nonvis);
2014
2015   if (oldsym == NULL)
2016     {
2017       // Version symbols are absolute symbols with name == version.
2018       // We don't want to force them to be local.
2019       if ((version == NULL
2020            || name != version
2021            || value != 0)
2022           && (binding == elfcpp::STB_LOCAL
2023               || this->version_script_.symbol_is_local(name)))
2024         this->force_local(sym);
2025       else if (version != NULL
2026                && (name != version || value != 0))
2027         sym->set_is_default();
2028       return sym;
2029     }
2030
2031   if (force_override
2032       || Symbol_table::should_override_with_special(oldsym, defined))
2033     this->override_with_special(oldsym, sym);
2034
2035   if (resolve_oldsym)
2036     return sym;
2037   else
2038     {
2039       delete sym;
2040       return oldsym;
2041     }
2042 }
2043
2044 // Define a set of symbols in output sections.
2045
2046 void
2047 Symbol_table::define_symbols(const Layout* layout, int count,
2048                              const Define_symbol_in_section* p,
2049                              bool only_if_ref)
2050 {
2051   for (int i = 0; i < count; ++i, ++p)
2052     {
2053       Output_section* os = layout->find_output_section(p->output_section);
2054       if (os != NULL)
2055         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2056                                     p->size, p->type, p->binding,
2057                                     p->visibility, p->nonvis,
2058                                     p->offset_is_from_end,
2059                                     only_if_ref || p->only_if_ref);
2060       else
2061         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2062                                  p->type, p->binding, p->visibility, p->nonvis,
2063                                  only_if_ref || p->only_if_ref,
2064                                  false);
2065     }
2066 }
2067
2068 // Define a set of symbols in output segments.
2069
2070 void
2071 Symbol_table::define_symbols(const Layout* layout, int count,
2072                              const Define_symbol_in_segment* p,
2073                              bool only_if_ref)
2074 {
2075   for (int i = 0; i < count; ++i, ++p)
2076     {
2077       Output_segment* os = layout->find_output_segment(p->segment_type,
2078                                                        p->segment_flags_set,
2079                                                        p->segment_flags_clear);
2080       if (os != NULL)
2081         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2082                                        p->size, p->type, p->binding,
2083                                        p->visibility, p->nonvis,
2084                                        p->offset_base,
2085                                        only_if_ref || p->only_if_ref);
2086       else
2087         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2088                                  p->type, p->binding, p->visibility, p->nonvis,
2089                                  only_if_ref || p->only_if_ref,
2090                                  false);
2091     }
2092 }
2093
2094 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2095 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2096 // the offset within POSD.
2097
2098 template<int size>
2099 void
2100 Symbol_table::define_with_copy_reloc(
2101     Sized_symbol<size>* csym,
2102     Output_data* posd,
2103     typename elfcpp::Elf_types<size>::Elf_Addr value)
2104 {
2105   gold_assert(csym->is_from_dynobj());
2106   gold_assert(!csym->is_copied_from_dynobj());
2107   Object* object = csym->object();
2108   gold_assert(object->is_dynamic());
2109   Dynobj* dynobj = static_cast<Dynobj*>(object);
2110
2111   // Our copied variable has to override any variable in a shared
2112   // library.
2113   elfcpp::STB binding = csym->binding();
2114   if (binding == elfcpp::STB_WEAK)
2115     binding = elfcpp::STB_GLOBAL;
2116
2117   this->define_in_output_data(csym->name(), csym->version(), COPY,
2118                               posd, value, csym->symsize(),
2119                               csym->type(), binding,
2120                               csym->visibility(), csym->nonvis(),
2121                               false, false);
2122
2123   csym->set_is_copied_from_dynobj();
2124   csym->set_needs_dynsym_entry();
2125
2126   this->copied_symbol_dynobjs_[csym] = dynobj;
2127
2128   // We have now defined all aliases, but we have not entered them all
2129   // in the copied_symbol_dynobjs_ map.
2130   if (csym->has_alias())
2131     {
2132       Symbol* sym = csym;
2133       while (true)
2134         {
2135           sym = this->weak_aliases_[sym];
2136           if (sym == csym)
2137             break;
2138           gold_assert(sym->output_data() == posd);
2139
2140           sym->set_is_copied_from_dynobj();
2141           this->copied_symbol_dynobjs_[sym] = dynobj;
2142         }
2143     }
2144 }
2145
2146 // SYM is defined using a COPY reloc.  Return the dynamic object where
2147 // the original definition was found.
2148
2149 Dynobj*
2150 Symbol_table::get_copy_source(const Symbol* sym) const
2151 {
2152   gold_assert(sym->is_copied_from_dynobj());
2153   Copied_symbol_dynobjs::const_iterator p =
2154     this->copied_symbol_dynobjs_.find(sym);
2155   gold_assert(p != this->copied_symbol_dynobjs_.end());
2156   return p->second;
2157 }
2158
2159 // Add any undefined symbols named on the command line.
2160
2161 void
2162 Symbol_table::add_undefined_symbols_from_command_line()
2163 {
2164   if (parameters->options().any_undefined())
2165     {
2166       if (parameters->target().get_size() == 32)
2167         {
2168 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2169           this->do_add_undefined_symbols_from_command_line<32>();
2170 #else
2171           gold_unreachable();
2172 #endif
2173         }
2174       else if (parameters->target().get_size() == 64)
2175         {
2176 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2177           this->do_add_undefined_symbols_from_command_line<64>();
2178 #else
2179           gold_unreachable();
2180 #endif
2181         }
2182       else
2183         gold_unreachable();
2184     }
2185 }
2186
2187 template<int size>
2188 void
2189 Symbol_table::do_add_undefined_symbols_from_command_line()
2190 {
2191   for (options::String_set::const_iterator p =
2192          parameters->options().undefined_begin();
2193        p != parameters->options().undefined_end();
2194        ++p)
2195     {
2196       const char* name = p->c_str();
2197
2198       if (this->lookup(name) != NULL)
2199         continue;
2200
2201       const char* version = NULL;
2202
2203       Sized_symbol<size>* sym;
2204       Sized_symbol<size>* oldsym;
2205       bool resolve_oldsym;
2206       if (parameters->target().is_big_endian())
2207         {
2208 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2209           sym = this->define_special_symbol<size, true>(&name, &version,
2210                                                         false, &oldsym,
2211                                                         &resolve_oldsym);
2212 #else
2213           gold_unreachable();
2214 #endif
2215         }
2216       else
2217         {
2218 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2219           sym = this->define_special_symbol<size, false>(&name, &version,
2220                                                          false, &oldsym,
2221                                                          &resolve_oldsym);
2222 #else
2223           gold_unreachable();
2224 #endif
2225         }
2226
2227       gold_assert(oldsym == NULL);
2228
2229       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2230                           elfcpp::STV_DEFAULT, 0);
2231       ++this->saw_undefined_;
2232     }
2233 }
2234
2235 // Set the dynamic symbol indexes.  INDEX is the index of the first
2236 // global dynamic symbol.  Pointers to the symbols are stored into the
2237 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2238 // updated dynamic symbol index.
2239
2240 unsigned int
2241 Symbol_table::set_dynsym_indexes(unsigned int index,
2242                                  std::vector<Symbol*>* syms,
2243                                  Stringpool* dynpool,
2244                                  Versions* versions)
2245 {
2246   for (Symbol_table_type::iterator p = this->table_.begin();
2247        p != this->table_.end();
2248        ++p)
2249     {
2250       Symbol* sym = p->second;
2251
2252       // Note that SYM may already have a dynamic symbol index, since
2253       // some symbols appear more than once in the symbol table, with
2254       // and without a version.
2255
2256       if (!sym->should_add_dynsym_entry())
2257         sym->set_dynsym_index(-1U);
2258       else if (!sym->has_dynsym_index())
2259         {
2260           sym->set_dynsym_index(index);
2261           ++index;
2262           syms->push_back(sym);
2263           dynpool->add(sym->name(), false, NULL);
2264
2265           // Record any version information.
2266           if (sym->version() != NULL)
2267             versions->record_version(this, dynpool, sym);
2268
2269           // If the symbol is defined in a dynamic object and is
2270           // referenced in a regular object, then mark the dynamic
2271           // object as needed.  This is used to implement --as-needed.
2272           if (sym->is_from_dynobj() && sym->in_reg())
2273             sym->object()->set_is_needed();
2274         }
2275     }
2276
2277   // Finish up the versions.  In some cases this may add new dynamic
2278   // symbols.
2279   index = versions->finalize(this, index, syms);
2280
2281   return index;
2282 }
2283
2284 // Set the final values for all the symbols.  The index of the first
2285 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2286 // file offset OFF.  Add their names to POOL.  Return the new file
2287 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2288
2289 off_t
2290 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2291                        size_t dyncount, Stringpool* pool,
2292                        unsigned int *plocal_symcount)
2293 {
2294   off_t ret;
2295
2296   gold_assert(*plocal_symcount != 0);
2297   this->first_global_index_ = *plocal_symcount;
2298
2299   this->dynamic_offset_ = dynoff;
2300   this->first_dynamic_global_index_ = dyn_global_index;
2301   this->dynamic_count_ = dyncount;
2302
2303   if (parameters->target().get_size() == 32)
2304     {
2305 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2306       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2307 #else
2308       gold_unreachable();
2309 #endif
2310     }
2311   else if (parameters->target().get_size() == 64)
2312     {
2313 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2314       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2315 #else
2316       gold_unreachable();
2317 #endif
2318     }
2319   else
2320     gold_unreachable();
2321
2322   // Now that we have the final symbol table, we can reliably note
2323   // which symbols should get warnings.
2324   this->warnings_.note_warnings(this);
2325
2326   return ret;
2327 }
2328
2329 // SYM is going into the symbol table at *PINDEX.  Add the name to
2330 // POOL, update *PINDEX and *POFF.
2331
2332 template<int size>
2333 void
2334 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2335                                   unsigned int* pindex, off_t* poff)
2336 {
2337   sym->set_symtab_index(*pindex);
2338   pool->add(sym->name(), false, NULL);
2339   ++*pindex;
2340   *poff += elfcpp::Elf_sizes<size>::sym_size;
2341 }
2342
2343 // Set the final value for all the symbols.  This is called after
2344 // Layout::finalize, so all the output sections have their final
2345 // address.
2346
2347 template<int size>
2348 off_t
2349 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2350                              unsigned int* plocal_symcount)
2351 {
2352   off = align_address(off, size >> 3);
2353   this->offset_ = off;
2354
2355   unsigned int index = *plocal_symcount;
2356   const unsigned int orig_index = index;
2357
2358   // First do all the symbols which have been forced to be local, as
2359   // they must appear before all global symbols.
2360   for (Forced_locals::iterator p = this->forced_locals_.begin();
2361        p != this->forced_locals_.end();
2362        ++p)
2363     {
2364       Symbol* sym = *p;
2365       gold_assert(sym->is_forced_local());
2366       if (this->sized_finalize_symbol<size>(sym))
2367         {
2368           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2369           ++*plocal_symcount;
2370         }
2371     }
2372
2373   // Now do all the remaining symbols.
2374   for (Symbol_table_type::iterator p = this->table_.begin();
2375        p != this->table_.end();
2376        ++p)
2377     {
2378       Symbol* sym = p->second;
2379       if (this->sized_finalize_symbol<size>(sym))
2380         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2381     }
2382
2383   this->output_count_ = index - orig_index;
2384
2385   return off;
2386 }
2387
2388 // Compute the final value of SYM and store status in location PSTATUS.
2389 // During relaxation, this may be called multiple times for a symbol to
2390 // compute its would-be final value in each relaxation pass.
2391
2392 template<int size>
2393 typename Sized_symbol<size>::Value_type
2394 Symbol_table::compute_final_value(
2395     const Sized_symbol<size>* sym,
2396     Compute_final_value_status* pstatus) const
2397 {
2398   typedef typename Sized_symbol<size>::Value_type Value_type;
2399   Value_type value;
2400
2401   switch (sym->source())
2402     {
2403     case Symbol::FROM_OBJECT:
2404       {
2405         bool is_ordinary;
2406         unsigned int shndx = sym->shndx(&is_ordinary);
2407
2408         if (!is_ordinary
2409             && shndx != elfcpp::SHN_ABS
2410             && !Symbol::is_common_shndx(shndx))
2411           {
2412             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2413             return 0;
2414           }
2415
2416         Object* symobj = sym->object();
2417         if (symobj->is_dynamic())
2418           {
2419             value = 0;
2420             shndx = elfcpp::SHN_UNDEF;
2421           }
2422         else if (symobj->pluginobj() != NULL)
2423           {
2424             value = 0;
2425             shndx = elfcpp::SHN_UNDEF;
2426           }
2427         else if (shndx == elfcpp::SHN_UNDEF)
2428           value = 0;
2429         else if (!is_ordinary
2430                  && (shndx == elfcpp::SHN_ABS
2431                      || Symbol::is_common_shndx(shndx)))
2432           value = sym->value();
2433         else
2434           {
2435             Relobj* relobj = static_cast<Relobj*>(symobj);
2436             Output_section* os = relobj->output_section(shndx);
2437
2438             if (this->is_section_folded(relobj, shndx))
2439               {
2440                 gold_assert(os == NULL);
2441                 // Get the os of the section it is folded onto.
2442                 Section_id folded = this->icf_->get_folded_section(relobj,
2443                                                                    shndx);
2444                 gold_assert(folded.first != NULL);
2445                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2446                 unsigned folded_shndx = folded.second;
2447
2448                 os = folded_obj->output_section(folded_shndx);  
2449                 gold_assert(os != NULL);
2450
2451                 // Replace (relobj, shndx) with canonical ICF input section.
2452                 shndx = folded_shndx;
2453                 relobj = folded_obj;
2454               }
2455
2456             uint64_t secoff64 = relobj->output_section_offset(shndx);
2457             if (os == NULL)
2458               {
2459                 bool static_or_reloc = (parameters->doing_static_link() ||
2460                                         parameters->options().relocatable());
2461                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2462
2463                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2464                 return 0;
2465               }
2466
2467             if (secoff64 == -1ULL)
2468               {
2469                 // The section needs special handling (e.g., a merge section).
2470
2471                 value = os->output_address(relobj, shndx, sym->value());
2472               }
2473             else
2474               {
2475                 Value_type secoff =
2476                   convert_types<Value_type, uint64_t>(secoff64);
2477                 if (sym->type() == elfcpp::STT_TLS)
2478                   value = sym->value() + os->tls_offset() + secoff;
2479                 else
2480                   value = sym->value() + os->address() + secoff;
2481               }
2482           }
2483       }
2484       break;
2485
2486     case Symbol::IN_OUTPUT_DATA:
2487       {
2488         Output_data* od = sym->output_data();
2489         value = sym->value();
2490         if (sym->type() != elfcpp::STT_TLS)
2491           value += od->address();
2492         else
2493           {
2494             Output_section* os = od->output_section();
2495             gold_assert(os != NULL);
2496             value += os->tls_offset() + (od->address() - os->address());
2497           }
2498         if (sym->offset_is_from_end())
2499           value += od->data_size();
2500       }
2501       break;
2502
2503     case Symbol::IN_OUTPUT_SEGMENT:
2504       {
2505         Output_segment* os = sym->output_segment();
2506         value = sym->value();
2507         if (sym->type() != elfcpp::STT_TLS)
2508           value += os->vaddr();
2509         switch (sym->offset_base())
2510           {
2511           case Symbol::SEGMENT_START:
2512             break;
2513           case Symbol::SEGMENT_END:
2514             value += os->memsz();
2515             break;
2516           case Symbol::SEGMENT_BSS:
2517             value += os->filesz();
2518             break;
2519           default:
2520             gold_unreachable();
2521           }
2522       }
2523       break;
2524
2525     case Symbol::IS_CONSTANT:
2526       value = sym->value();
2527       break;
2528
2529     case Symbol::IS_UNDEFINED:
2530       value = 0;
2531       break;
2532
2533     default:
2534       gold_unreachable();
2535     }
2536
2537   *pstatus = CFVS_OK;
2538   return value;
2539 }
2540
2541 // Finalize the symbol SYM.  This returns true if the symbol should be
2542 // added to the symbol table, false otherwise.
2543
2544 template<int size>
2545 bool
2546 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2547 {
2548   typedef typename Sized_symbol<size>::Value_type Value_type;
2549
2550   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2551
2552   // The default version of a symbol may appear twice in the symbol
2553   // table.  We only need to finalize it once.
2554   if (sym->has_symtab_index())
2555     return false;
2556
2557   if (!sym->in_reg())
2558     {
2559       gold_assert(!sym->has_symtab_index());
2560       sym->set_symtab_index(-1U);
2561       gold_assert(sym->dynsym_index() == -1U);
2562       return false;
2563     }
2564
2565   // Compute final symbol value.
2566   Compute_final_value_status status;
2567   Value_type value = this->compute_final_value(sym, &status);
2568
2569   switch (status)
2570     {
2571     case CFVS_OK:
2572       break;
2573     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2574       {
2575         bool is_ordinary;
2576         unsigned int shndx = sym->shndx(&is_ordinary);
2577         gold_error(_("%s: unsupported symbol section 0x%x"),
2578                    sym->demangled_name().c_str(), shndx);
2579       }
2580       break;
2581     case CFVS_NO_OUTPUT_SECTION:
2582       sym->set_symtab_index(-1U);
2583       return false;
2584     default:
2585       gold_unreachable();
2586     }
2587
2588   sym->set_value(value);
2589
2590   if (parameters->options().strip_all()
2591       || !parameters->options().should_retain_symbol(sym->name()))
2592     {
2593       sym->set_symtab_index(-1U);
2594       return false;
2595     }
2596
2597   return true;
2598 }
2599
2600 // Write out the global symbols.
2601
2602 void
2603 Symbol_table::write_globals(const Stringpool* sympool,
2604                             const Stringpool* dynpool,
2605                             Output_symtab_xindex* symtab_xindex,
2606                             Output_symtab_xindex* dynsym_xindex,
2607                             Output_file* of) const
2608 {
2609   switch (parameters->size_and_endianness())
2610     {
2611 #ifdef HAVE_TARGET_32_LITTLE
2612     case Parameters::TARGET_32_LITTLE:
2613       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2614                                            dynsym_xindex, of);
2615       break;
2616 #endif
2617 #ifdef HAVE_TARGET_32_BIG
2618     case Parameters::TARGET_32_BIG:
2619       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2620                                           dynsym_xindex, of);
2621       break;
2622 #endif
2623 #ifdef HAVE_TARGET_64_LITTLE
2624     case Parameters::TARGET_64_LITTLE:
2625       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2626                                            dynsym_xindex, of);
2627       break;
2628 #endif
2629 #ifdef HAVE_TARGET_64_BIG
2630     case Parameters::TARGET_64_BIG:
2631       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2632                                           dynsym_xindex, of);
2633       break;
2634 #endif
2635     default:
2636       gold_unreachable();
2637     }
2638 }
2639
2640 // Write out the global symbols.
2641
2642 template<int size, bool big_endian>
2643 void
2644 Symbol_table::sized_write_globals(const Stringpool* sympool,
2645                                   const Stringpool* dynpool,
2646                                   Output_symtab_xindex* symtab_xindex,
2647                                   Output_symtab_xindex* dynsym_xindex,
2648                                   Output_file* of) const
2649 {
2650   const Target& target = parameters->target();
2651
2652   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2653
2654   const unsigned int output_count = this->output_count_;
2655   const section_size_type oview_size = output_count * sym_size;
2656   const unsigned int first_global_index = this->first_global_index_;
2657   unsigned char* psyms;
2658   if (this->offset_ == 0 || output_count == 0)
2659     psyms = NULL;
2660   else
2661     psyms = of->get_output_view(this->offset_, oview_size);
2662
2663   const unsigned int dynamic_count = this->dynamic_count_;
2664   const section_size_type dynamic_size = dynamic_count * sym_size;
2665   const unsigned int first_dynamic_global_index =
2666     this->first_dynamic_global_index_;
2667   unsigned char* dynamic_view;
2668   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2669     dynamic_view = NULL;
2670   else
2671     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2672
2673   for (Symbol_table_type::const_iterator p = this->table_.begin();
2674        p != this->table_.end();
2675        ++p)
2676     {
2677       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2678
2679       // Possibly warn about unresolved symbols in shared libraries.
2680       this->warn_about_undefined_dynobj_symbol(sym);
2681
2682       unsigned int sym_index = sym->symtab_index();
2683       unsigned int dynsym_index;
2684       if (dynamic_view == NULL)
2685         dynsym_index = -1U;
2686       else
2687         dynsym_index = sym->dynsym_index();
2688
2689       if (sym_index == -1U && dynsym_index == -1U)
2690         {
2691           // This symbol is not included in the output file.
2692           continue;
2693         }
2694
2695       unsigned int shndx;
2696       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2697       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2698       switch (sym->source())
2699         {
2700         case Symbol::FROM_OBJECT:
2701           {
2702             bool is_ordinary;
2703             unsigned int in_shndx = sym->shndx(&is_ordinary);
2704
2705             if (!is_ordinary
2706                 && in_shndx != elfcpp::SHN_ABS
2707                 && !Symbol::is_common_shndx(in_shndx))
2708               {
2709                 gold_error(_("%s: unsupported symbol section 0x%x"),
2710                            sym->demangled_name().c_str(), in_shndx);
2711                 shndx = in_shndx;
2712               }
2713             else
2714               {
2715                 Object* symobj = sym->object();
2716                 if (symobj->is_dynamic())
2717                   {
2718                     if (sym->needs_dynsym_value())
2719                       dynsym_value = target.dynsym_value(sym);
2720                     shndx = elfcpp::SHN_UNDEF;
2721                   }
2722                 else if (symobj->pluginobj() != NULL)
2723                   shndx = elfcpp::SHN_UNDEF;
2724                 else if (in_shndx == elfcpp::SHN_UNDEF
2725                          || (!is_ordinary
2726                              && (in_shndx == elfcpp::SHN_ABS
2727                                  || Symbol::is_common_shndx(in_shndx))))
2728                   shndx = in_shndx;
2729                 else
2730                   {
2731                     Relobj* relobj = static_cast<Relobj*>(symobj);
2732                     Output_section* os = relobj->output_section(in_shndx);
2733                     if (this->is_section_folded(relobj, in_shndx))
2734                       {
2735                         // This global symbol must be written out even though
2736                         // it is folded.
2737                         // Get the os of the section it is folded onto.
2738                         Section_id folded =
2739                              this->icf_->get_folded_section(relobj, in_shndx);
2740                         gold_assert(folded.first !=NULL);
2741                         Relobj* folded_obj = 
2742                           reinterpret_cast<Relobj*>(folded.first);
2743                         os = folded_obj->output_section(folded.second);  
2744                         gold_assert(os != NULL);
2745                       }
2746                     gold_assert(os != NULL);
2747                     shndx = os->out_shndx();
2748
2749                     if (shndx >= elfcpp::SHN_LORESERVE)
2750                       {
2751                         if (sym_index != -1U)
2752                           symtab_xindex->add(sym_index, shndx);
2753                         if (dynsym_index != -1U)
2754                           dynsym_xindex->add(dynsym_index, shndx);
2755                         shndx = elfcpp::SHN_XINDEX;
2756                       }
2757
2758                     // In object files symbol values are section
2759                     // relative.
2760                     if (parameters->options().relocatable())
2761                       sym_value -= os->address();
2762                   }
2763               }
2764           }
2765           break;
2766
2767         case Symbol::IN_OUTPUT_DATA:
2768           shndx = sym->output_data()->out_shndx();
2769           if (shndx >= elfcpp::SHN_LORESERVE)
2770             {
2771               if (sym_index != -1U)
2772                 symtab_xindex->add(sym_index, shndx);
2773               if (dynsym_index != -1U)
2774                 dynsym_xindex->add(dynsym_index, shndx);
2775               shndx = elfcpp::SHN_XINDEX;
2776             }
2777           break;
2778
2779         case Symbol::IN_OUTPUT_SEGMENT:
2780           shndx = elfcpp::SHN_ABS;
2781           break;
2782
2783         case Symbol::IS_CONSTANT:
2784           shndx = elfcpp::SHN_ABS;
2785           break;
2786
2787         case Symbol::IS_UNDEFINED:
2788           shndx = elfcpp::SHN_UNDEF;
2789           break;
2790
2791         default:
2792           gold_unreachable();
2793         }
2794
2795       if (sym_index != -1U)
2796         {
2797           sym_index -= first_global_index;
2798           gold_assert(sym_index < output_count);
2799           unsigned char* ps = psyms + (sym_index * sym_size);
2800           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2801                                                      sympool, ps);
2802         }
2803
2804       if (dynsym_index != -1U)
2805         {
2806           dynsym_index -= first_dynamic_global_index;
2807           gold_assert(dynsym_index < dynamic_count);
2808           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2809           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2810                                                      dynpool, pd);
2811         }
2812     }
2813
2814   of->write_output_view(this->offset_, oview_size, psyms);
2815   if (dynamic_view != NULL)
2816     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2817 }
2818
2819 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2820 // strtab holding the name.
2821
2822 template<int size, bool big_endian>
2823 void
2824 Symbol_table::sized_write_symbol(
2825     Sized_symbol<size>* sym,
2826     typename elfcpp::Elf_types<size>::Elf_Addr value,
2827     unsigned int shndx,
2828     const Stringpool* pool,
2829     unsigned char* p) const
2830 {
2831   elfcpp::Sym_write<size, big_endian> osym(p);
2832   osym.put_st_name(pool->get_offset(sym->name()));
2833   osym.put_st_value(value);
2834   // Use a symbol size of zero for undefined symbols from shared libraries.
2835   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2836     osym.put_st_size(0);
2837   else
2838     osym.put_st_size(sym->symsize());
2839   elfcpp::STT type = sym->type();
2840   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2841   if (type == elfcpp::STT_GNU_IFUNC
2842       && sym->is_from_dynobj())
2843     type = elfcpp::STT_FUNC;
2844   // A version script may have overridden the default binding.
2845   if (sym->is_forced_local())
2846     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2847   else
2848     osym.put_st_info(elfcpp::elf_st_info(sym->binding(), type));
2849   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2850   osym.put_st_shndx(shndx);
2851 }
2852
2853 // Check for unresolved symbols in shared libraries.  This is
2854 // controlled by the --allow-shlib-undefined option.
2855
2856 // We only warn about libraries for which we have seen all the
2857 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2858 // which were not seen in this link.  If we didn't see a DT_NEEDED
2859 // entry, we aren't going to be able to reliably report whether the
2860 // symbol is undefined.
2861
2862 // We also don't warn about libraries found in a system library
2863 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2864 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2865 // can have undefined references satisfied by ld-linux.so.
2866
2867 inline void
2868 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2869 {
2870   bool dummy;
2871   if (sym->source() == Symbol::FROM_OBJECT
2872       && sym->object()->is_dynamic()
2873       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2874       && sym->binding() != elfcpp::STB_WEAK
2875       && !parameters->options().allow_shlib_undefined()
2876       && !parameters->target().is_defined_by_abi(sym)
2877       && !sym->object()->is_in_system_directory())
2878     {
2879       // A very ugly cast.
2880       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2881       if (!dynobj->has_unknown_needed_entries())
2882         gold_undefined_symbol(sym);
2883     }
2884 }
2885
2886 // Write out a section symbol.  Return the update offset.
2887
2888 void
2889 Symbol_table::write_section_symbol(const Output_section *os,
2890                                    Output_symtab_xindex* symtab_xindex,
2891                                    Output_file* of,
2892                                    off_t offset) const
2893 {
2894   switch (parameters->size_and_endianness())
2895     {
2896 #ifdef HAVE_TARGET_32_LITTLE
2897     case Parameters::TARGET_32_LITTLE:
2898       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2899                                                   offset);
2900       break;
2901 #endif
2902 #ifdef HAVE_TARGET_32_BIG
2903     case Parameters::TARGET_32_BIG:
2904       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2905                                                  offset);
2906       break;
2907 #endif
2908 #ifdef HAVE_TARGET_64_LITTLE
2909     case Parameters::TARGET_64_LITTLE:
2910       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2911                                                   offset);
2912       break;
2913 #endif
2914 #ifdef HAVE_TARGET_64_BIG
2915     case Parameters::TARGET_64_BIG:
2916       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2917                                                  offset);
2918       break;
2919 #endif
2920     default:
2921       gold_unreachable();
2922     }
2923 }
2924
2925 // Write out a section symbol, specialized for size and endianness.
2926
2927 template<int size, bool big_endian>
2928 void
2929 Symbol_table::sized_write_section_symbol(const Output_section* os,
2930                                          Output_symtab_xindex* symtab_xindex,
2931                                          Output_file* of,
2932                                          off_t offset) const
2933 {
2934   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2935
2936   unsigned char* pov = of->get_output_view(offset, sym_size);
2937
2938   elfcpp::Sym_write<size, big_endian> osym(pov);
2939   osym.put_st_name(0);
2940   if (parameters->options().relocatable())
2941     osym.put_st_value(0);
2942   else
2943     osym.put_st_value(os->address());
2944   osym.put_st_size(0);
2945   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2946                                        elfcpp::STT_SECTION));
2947   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2948
2949   unsigned int shndx = os->out_shndx();
2950   if (shndx >= elfcpp::SHN_LORESERVE)
2951     {
2952       symtab_xindex->add(os->symtab_index(), shndx);
2953       shndx = elfcpp::SHN_XINDEX;
2954     }
2955   osym.put_st_shndx(shndx);
2956
2957   of->write_output_view(offset, sym_size, pov);
2958 }
2959
2960 // Print statistical information to stderr.  This is used for --stats.
2961
2962 void
2963 Symbol_table::print_stats() const
2964 {
2965 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2966   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2967           program_name, this->table_.size(), this->table_.bucket_count());
2968 #else
2969   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2970           program_name, this->table_.size());
2971 #endif
2972   this->namepool_.print_stats("symbol table stringpool");
2973 }
2974
2975 // We check for ODR violations by looking for symbols with the same
2976 // name for which the debugging information reports that they were
2977 // defined in different source locations.  When comparing the source
2978 // location, we consider instances with the same base filename and
2979 // line number to be the same.  This is because different object
2980 // files/shared libraries can include the same header file using
2981 // different paths, and we don't want to report an ODR violation in
2982 // that case.
2983
2984 // This struct is used to compare line information, as returned by
2985 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2986 // operator used with std::set.
2987
2988 struct Odr_violation_compare
2989 {
2990   bool
2991   operator()(const std::string& s1, const std::string& s2) const
2992   {
2993     std::string::size_type pos1 = s1.rfind('/');
2994     std::string::size_type pos2 = s2.rfind('/');
2995     if (pos1 == std::string::npos
2996         || pos2 == std::string::npos)
2997       return s1 < s2;
2998     return s1.compare(pos1, std::string::npos,
2999                       s2, pos2, std::string::npos) < 0;
3000   }
3001 };
3002
3003 // Check candidate_odr_violations_ to find symbols with the same name
3004 // but apparently different definitions (different source-file/line-no).
3005
3006 void
3007 Symbol_table::detect_odr_violations(const Task* task,
3008                                     const char* output_file_name) const
3009 {
3010   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3011        it != candidate_odr_violations_.end();
3012        ++it)
3013     {
3014       const char* symbol_name = it->first;
3015       // We use a sorted set so the output is deterministic.
3016       std::set<std::string, Odr_violation_compare> line_nums;
3017
3018       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3019                locs = it->second.begin();
3020            locs != it->second.end();
3021            ++locs)
3022         {
3023           // We need to lock the object in order to read it.  This
3024           // means that we have to run in a singleton Task.  If we
3025           // want to run this in a general Task for better
3026           // performance, we will need one Task for object, plus
3027           // appropriate locking to ensure that we don't conflict with
3028           // other uses of the object.  Also note, one_addr2line is not
3029           // currently thread-safe.
3030           Task_lock_obj<Object> tl(task, locs->object);
3031           // 16 is the size of the object-cache that one_addr2line should use.
3032           std::string lineno = Dwarf_line_info::one_addr2line(
3033               locs->object, locs->shndx, locs->offset, 16);
3034           if (!lineno.empty())
3035             line_nums.insert(lineno);
3036         }
3037
3038       if (line_nums.size() > 1)
3039         {
3040           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3041                          "places (possible ODR violation):"),
3042                        output_file_name, demangle(symbol_name).c_str());
3043           for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3044                it2 != line_nums.end();
3045                ++it2)
3046             fprintf(stderr, "  %s\n", it2->c_str());
3047         }
3048     }
3049   // We only call one_addr2line() in this function, so we can clear its cache.
3050   Dwarf_line_info::clear_addr2line_cache();
3051 }
3052
3053 // Warnings functions.
3054
3055 // Add a new warning.
3056
3057 void
3058 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3059                       const std::string& warning)
3060 {
3061   name = symtab->canonicalize_name(name);
3062   this->warnings_[name].set(obj, warning);
3063 }
3064
3065 // Look through the warnings and mark the symbols for which we should
3066 // warn.  This is called during Layout::finalize when we know the
3067 // sources for all the symbols.
3068
3069 void
3070 Warnings::note_warnings(Symbol_table* symtab)
3071 {
3072   for (Warning_table::iterator p = this->warnings_.begin();
3073        p != this->warnings_.end();
3074        ++p)
3075     {
3076       Symbol* sym = symtab->lookup(p->first, NULL);
3077       if (sym != NULL
3078           && sym->source() == Symbol::FROM_OBJECT
3079           && sym->object() == p->second.object)
3080         sym->set_has_warning();
3081     }
3082 }
3083
3084 // Issue a warning.  This is called when we see a relocation against a
3085 // symbol for which has a warning.
3086
3087 template<int size, bool big_endian>
3088 void
3089 Warnings::issue_warning(const Symbol* sym,
3090                         const Relocate_info<size, big_endian>* relinfo,
3091                         size_t relnum, off_t reloffset) const
3092 {
3093   gold_assert(sym->has_warning());
3094   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3095   gold_assert(p != this->warnings_.end());
3096   gold_warning_at_location(relinfo, relnum, reloffset,
3097                            "%s", p->second.text.c_str());
3098 }
3099
3100 // Instantiate the templates we need.  We could use the configure
3101 // script to restrict this to only the ones needed for implemented
3102 // targets.
3103
3104 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3105 template
3106 void
3107 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3108 #endif
3109
3110 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3111 template
3112 void
3113 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3114 #endif
3115
3116 #ifdef HAVE_TARGET_32_LITTLE
3117 template
3118 void
3119 Symbol_table::add_from_relobj<32, false>(
3120     Sized_relobj<32, false>* relobj,
3121     const unsigned char* syms,
3122     size_t count,
3123     size_t symndx_offset,
3124     const char* sym_names,
3125     size_t sym_name_size,
3126     Sized_relobj<32, false>::Symbols* sympointers,
3127     size_t* defined);
3128 #endif
3129
3130 #ifdef HAVE_TARGET_32_BIG
3131 template
3132 void
3133 Symbol_table::add_from_relobj<32, true>(
3134     Sized_relobj<32, true>* relobj,
3135     const unsigned char* syms,
3136     size_t count,
3137     size_t symndx_offset,
3138     const char* sym_names,
3139     size_t sym_name_size,
3140     Sized_relobj<32, true>::Symbols* sympointers,
3141     size_t* defined);
3142 #endif
3143
3144 #ifdef HAVE_TARGET_64_LITTLE
3145 template
3146 void
3147 Symbol_table::add_from_relobj<64, false>(
3148     Sized_relobj<64, false>* relobj,
3149     const unsigned char* syms,
3150     size_t count,
3151     size_t symndx_offset,
3152     const char* sym_names,
3153     size_t sym_name_size,
3154     Sized_relobj<64, false>::Symbols* sympointers,
3155     size_t* defined);
3156 #endif
3157
3158 #ifdef HAVE_TARGET_64_BIG
3159 template
3160 void
3161 Symbol_table::add_from_relobj<64, true>(
3162     Sized_relobj<64, true>* relobj,
3163     const unsigned char* syms,
3164     size_t count,
3165     size_t symndx_offset,
3166     const char* sym_names,
3167     size_t sym_name_size,
3168     Sized_relobj<64, true>::Symbols* sympointers,
3169     size_t* defined);
3170 #endif
3171
3172 #ifdef HAVE_TARGET_32_LITTLE
3173 template
3174 Symbol*
3175 Symbol_table::add_from_pluginobj<32, false>(
3176     Sized_pluginobj<32, false>* obj,
3177     const char* name,
3178     const char* ver,
3179     elfcpp::Sym<32, false>* sym);
3180 #endif
3181
3182 #ifdef HAVE_TARGET_32_BIG
3183 template
3184 Symbol*
3185 Symbol_table::add_from_pluginobj<32, true>(
3186     Sized_pluginobj<32, true>* obj,
3187     const char* name,
3188     const char* ver,
3189     elfcpp::Sym<32, true>* sym);
3190 #endif
3191
3192 #ifdef HAVE_TARGET_64_LITTLE
3193 template
3194 Symbol*
3195 Symbol_table::add_from_pluginobj<64, false>(
3196     Sized_pluginobj<64, false>* obj,
3197     const char* name,
3198     const char* ver,
3199     elfcpp::Sym<64, false>* sym);
3200 #endif
3201
3202 #ifdef HAVE_TARGET_64_BIG
3203 template
3204 Symbol*
3205 Symbol_table::add_from_pluginobj<64, true>(
3206     Sized_pluginobj<64, true>* obj,
3207     const char* name,
3208     const char* ver,
3209     elfcpp::Sym<64, true>* sym);
3210 #endif
3211
3212 #ifdef HAVE_TARGET_32_LITTLE
3213 template
3214 void
3215 Symbol_table::add_from_dynobj<32, false>(
3216     Sized_dynobj<32, false>* dynobj,
3217     const unsigned char* syms,
3218     size_t count,
3219     const char* sym_names,
3220     size_t sym_name_size,
3221     const unsigned char* versym,
3222     size_t versym_size,
3223     const std::vector<const char*>* version_map,
3224     Sized_relobj<32, false>::Symbols* sympointers,
3225     size_t* defined);
3226 #endif
3227
3228 #ifdef HAVE_TARGET_32_BIG
3229 template
3230 void
3231 Symbol_table::add_from_dynobj<32, true>(
3232     Sized_dynobj<32, true>* dynobj,
3233     const unsigned char* syms,
3234     size_t count,
3235     const char* sym_names,
3236     size_t sym_name_size,
3237     const unsigned char* versym,
3238     size_t versym_size,
3239     const std::vector<const char*>* version_map,
3240     Sized_relobj<32, true>::Symbols* sympointers,
3241     size_t* defined);
3242 #endif
3243
3244 #ifdef HAVE_TARGET_64_LITTLE
3245 template
3246 void
3247 Symbol_table::add_from_dynobj<64, false>(
3248     Sized_dynobj<64, false>* dynobj,
3249     const unsigned char* syms,
3250     size_t count,
3251     const char* sym_names,
3252     size_t sym_name_size,
3253     const unsigned char* versym,
3254     size_t versym_size,
3255     const std::vector<const char*>* version_map,
3256     Sized_relobj<64, false>::Symbols* sympointers,
3257     size_t* defined);
3258 #endif
3259
3260 #ifdef HAVE_TARGET_64_BIG
3261 template
3262 void
3263 Symbol_table::add_from_dynobj<64, true>(
3264     Sized_dynobj<64, true>* dynobj,
3265     const unsigned char* syms,
3266     size_t count,
3267     const char* sym_names,
3268     size_t sym_name_size,
3269     const unsigned char* versym,
3270     size_t versym_size,
3271     const std::vector<const char*>* version_map,
3272     Sized_relobj<64, true>::Symbols* sympointers,
3273     size_t* defined);
3274 #endif
3275
3276 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3277 template
3278 void
3279 Symbol_table::define_with_copy_reloc<32>(
3280     Sized_symbol<32>* sym,
3281     Output_data* posd,
3282     elfcpp::Elf_types<32>::Elf_Addr value);
3283 #endif
3284
3285 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3286 template
3287 void
3288 Symbol_table::define_with_copy_reloc<64>(
3289     Sized_symbol<64>* sym,
3290     Output_data* posd,
3291     elfcpp::Elf_types<64>::Elf_Addr value);
3292 #endif
3293
3294 #ifdef HAVE_TARGET_32_LITTLE
3295 template
3296 void
3297 Warnings::issue_warning<32, false>(const Symbol* sym,
3298                                    const Relocate_info<32, false>* relinfo,
3299                                    size_t relnum, off_t reloffset) const;
3300 #endif
3301
3302 #ifdef HAVE_TARGET_32_BIG
3303 template
3304 void
3305 Warnings::issue_warning<32, true>(const Symbol* sym,
3306                                   const Relocate_info<32, true>* relinfo,
3307                                   size_t relnum, off_t reloffset) const;
3308 #endif
3309
3310 #ifdef HAVE_TARGET_64_LITTLE
3311 template
3312 void
3313 Warnings::issue_warning<64, false>(const Symbol* sym,
3314                                    const Relocate_info<64, false>* relinfo,
3315                                    size_t relnum, off_t reloffset) const;
3316 #endif
3317
3318 #ifdef HAVE_TARGET_64_BIG
3319 template
3320 void
3321 Warnings::issue_warning<64, true>(const Symbol* sym,
3322                                   const Relocate_info<64, true>* relinfo,
3323                                   size_t relnum, off_t reloffset) const;
3324 #endif
3325
3326 } // End namespace gold.
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