2009-10-09 Doug Kwan <dougkwan@google.com>
[external/binutils.git] / gold / symtab.cc
1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
32
33 #include "gc.h"
34 #include "object.h"
35 #include "dwarf_reader.h"
36 #include "dynobj.h"
37 #include "output.h"
38 #include "target.h"
39 #include "workqueue.h"
40 #include "symtab.h"
41 #include "demangle.h"   // needed for --dynamic-list-cpp-new
42 #include "plugin.h"
43
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol.  This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54                     elfcpp::STT type, elfcpp::STB binding,
55                     elfcpp::STV visibility, unsigned char nonvis)
56 {
57   this->name_ = name;
58   this->version_ = version;
59   this->symtab_index_ = 0;
60   this->dynsym_index_ = 0;
61   this->got_offsets_.init();
62   this->plt_offset_ = 0;
63   this->type_ = type;
64   this->binding_ = binding;
65   this->visibility_ = visibility;
66   this->nonvis_ = nonvis;
67   this->is_target_special_ = false;
68   this->is_def_ = false;
69   this->is_forwarder_ = false;
70   this->has_alias_ = false;
71   this->needs_dynsym_entry_ = false;
72   this->in_reg_ = false;
73   this->in_dyn_ = false;
74   this->has_plt_offset_ = false;
75   this->has_warning_ = false;
76   this->is_copied_from_dynobj_ = false;
77   this->is_forced_local_ = false;
78   this->is_ordinary_shndx_ = false;
79   this->in_real_elf_ = false;
80 }
81
82 // Return the demangled version of the symbol's name, but only
83 // if the --demangle flag was set.
84
85 static std::string
86 demangle(const char* name)
87 {
88   if (!parameters->options().do_demangle())
89     return name;
90
91   // cplus_demangle allocates memory for the result it returns,
92   // and returns NULL if the name is already demangled.
93   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
94   if (demangled_name == NULL)
95     return name;
96
97   std::string retval(demangled_name);
98   free(demangled_name);
99   return retval;
100 }
101
102 std::string
103 Symbol::demangled_name() const
104 {
105   return demangle(this->name());
106 }
107
108 // Initialize the fields in the base class Symbol for SYM in OBJECT.
109
110 template<int size, bool big_endian>
111 void
112 Symbol::init_base_object(const char* name, const char* version, Object* object,
113                          const elfcpp::Sym<size, big_endian>& sym,
114                          unsigned int st_shndx, bool is_ordinary)
115 {
116   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
117                     sym.get_st_visibility(), sym.get_st_nonvis());
118   this->u_.from_object.object = object;
119   this->u_.from_object.shndx = st_shndx;
120   this->is_ordinary_shndx_ = is_ordinary;
121   this->source_ = FROM_OBJECT;
122   this->in_reg_ = !object->is_dynamic();
123   this->in_dyn_ = object->is_dynamic();
124   this->in_real_elf_ = object->pluginobj() == NULL;
125 }
126
127 // Initialize the fields in the base class Symbol for a symbol defined
128 // in an Output_data.
129
130 void
131 Symbol::init_base_output_data(const char* name, const char* version,
132                               Output_data* od, elfcpp::STT type,
133                               elfcpp::STB binding, elfcpp::STV visibility,
134                               unsigned char nonvis, bool offset_is_from_end)
135 {
136   this->init_fields(name, version, type, binding, visibility, nonvis);
137   this->u_.in_output_data.output_data = od;
138   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
139   this->source_ = IN_OUTPUT_DATA;
140   this->in_reg_ = true;
141   this->in_real_elf_ = true;
142 }
143
144 // Initialize the fields in the base class Symbol for a symbol defined
145 // in an Output_segment.
146
147 void
148 Symbol::init_base_output_segment(const char* name, const char* version,
149                                  Output_segment* os, elfcpp::STT type,
150                                  elfcpp::STB binding, elfcpp::STV visibility,
151                                  unsigned char nonvis,
152                                  Segment_offset_base offset_base)
153 {
154   this->init_fields(name, version, type, binding, visibility, nonvis);
155   this->u_.in_output_segment.output_segment = os;
156   this->u_.in_output_segment.offset_base = offset_base;
157   this->source_ = IN_OUTPUT_SEGMENT;
158   this->in_reg_ = true;
159   this->in_real_elf_ = true;
160 }
161
162 // Initialize the fields in the base class Symbol for a symbol defined
163 // as a constant.
164
165 void
166 Symbol::init_base_constant(const char* name, const char* version,
167                            elfcpp::STT type, elfcpp::STB binding,
168                            elfcpp::STV visibility, unsigned char nonvis)
169 {
170   this->init_fields(name, version, type, binding, visibility, nonvis);
171   this->source_ = IS_CONSTANT;
172   this->in_reg_ = true;
173   this->in_real_elf_ = true;
174 }
175
176 // Initialize the fields in the base class Symbol for an undefined
177 // symbol.
178
179 void
180 Symbol::init_base_undefined(const char* name, const char* version,
181                             elfcpp::STT type, elfcpp::STB binding,
182                             elfcpp::STV visibility, unsigned char nonvis)
183 {
184   this->init_fields(name, version, type, binding, visibility, nonvis);
185   this->dynsym_index_ = -1U;
186   this->source_ = IS_UNDEFINED;
187   this->in_reg_ = true;
188   this->in_real_elf_ = true;
189 }
190
191 // Allocate a common symbol in the base.
192
193 void
194 Symbol::allocate_base_common(Output_data* od)
195 {
196   gold_assert(this->is_common());
197   this->source_ = IN_OUTPUT_DATA;
198   this->u_.in_output_data.output_data = od;
199   this->u_.in_output_data.offset_is_from_end = false;
200 }
201
202 // Initialize the fields in Sized_symbol for SYM in OBJECT.
203
204 template<int size>
205 template<bool big_endian>
206 void
207 Sized_symbol<size>::init_object(const char* name, const char* version,
208                                 Object* object,
209                                 const elfcpp::Sym<size, big_endian>& sym,
210                                 unsigned int st_shndx, bool is_ordinary)
211 {
212   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
213   this->value_ = sym.get_st_value();
214   this->symsize_ = sym.get_st_size();
215 }
216
217 // Initialize the fields in Sized_symbol for a symbol defined in an
218 // Output_data.
219
220 template<int size>
221 void
222 Sized_symbol<size>::init_output_data(const char* name, const char* version,
223                                      Output_data* od, Value_type value,
224                                      Size_type symsize, elfcpp::STT type,
225                                      elfcpp::STB binding,
226                                      elfcpp::STV visibility,
227                                      unsigned char nonvis,
228                                      bool offset_is_from_end)
229 {
230   this->init_base_output_data(name, version, od, type, binding, visibility,
231                               nonvis, offset_is_from_end);
232   this->value_ = value;
233   this->symsize_ = symsize;
234 }
235
236 // Initialize the fields in Sized_symbol for a symbol defined in an
237 // Output_segment.
238
239 template<int size>
240 void
241 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
242                                         Output_segment* os, Value_type value,
243                                         Size_type symsize, elfcpp::STT type,
244                                         elfcpp::STB binding,
245                                         elfcpp::STV visibility,
246                                         unsigned char nonvis,
247                                         Segment_offset_base offset_base)
248 {
249   this->init_base_output_segment(name, version, os, type, binding, visibility,
250                                  nonvis, offset_base);
251   this->value_ = value;
252   this->symsize_ = symsize;
253 }
254
255 // Initialize the fields in Sized_symbol for a symbol defined as a
256 // constant.
257
258 template<int size>
259 void
260 Sized_symbol<size>::init_constant(const char* name, const char* version,
261                                   Value_type value, Size_type symsize,
262                                   elfcpp::STT type, elfcpp::STB binding,
263                                   elfcpp::STV visibility, unsigned char nonvis)
264 {
265   this->init_base_constant(name, version, type, binding, visibility, nonvis);
266   this->value_ = value;
267   this->symsize_ = symsize;
268 }
269
270 // Initialize the fields in Sized_symbol for an undefined symbol.
271
272 template<int size>
273 void
274 Sized_symbol<size>::init_undefined(const char* name, const char* version,
275                                    elfcpp::STT type, elfcpp::STB binding,
276                                    elfcpp::STV visibility, unsigned char nonvis)
277 {
278   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
279   this->value_ = 0;
280   this->symsize_ = 0;
281 }
282
283 // Return true if SHNDX represents a common symbol.
284
285 bool
286 Symbol::is_common_shndx(unsigned int shndx)
287 {
288   return (shndx == elfcpp::SHN_COMMON
289           || shndx == parameters->target().small_common_shndx()
290           || shndx == parameters->target().large_common_shndx());
291 }
292
293 // Allocate a common symbol.
294
295 template<int size>
296 void
297 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
298 {
299   this->allocate_base_common(od);
300   this->value_ = value;
301 }
302
303 // The ""'s around str ensure str is a string literal, so sizeof works.
304 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
305
306 // Return true if this symbol should be added to the dynamic symbol
307 // table.
308
309 inline bool
310 Symbol::should_add_dynsym_entry() const
311 {
312   // If the symbol is used by a dynamic relocation, we need to add it.
313   if (this->needs_dynsym_entry())
314     return true;
315
316   // If this symbol's section is not added, the symbol need not be added. 
317   // The section may have been GCed.  Note that export_dynamic is being 
318   // overridden here.  This should not be done for shared objects.
319   if (parameters->options().gc_sections() 
320       && !parameters->options().shared()
321       && this->source() == Symbol::FROM_OBJECT
322       && !this->object()->is_dynamic())
323     {
324       Relobj* relobj = static_cast<Relobj*>(this->object());
325       bool is_ordinary;
326       unsigned int shndx = this->shndx(&is_ordinary);
327       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
328           && !relobj->is_section_included(shndx))
329         return false;
330     }
331
332   // If the symbol was forced local in a version script, do not add it.
333   if (this->is_forced_local())
334     return false;
335
336   // If the symbol was forced dynamic in a --dynamic-list file, add it.
337   if (parameters->options().in_dynamic_list(this->name()))
338     return true;
339
340   // If dynamic-list-data was specified, add any STT_OBJECT.
341   if (parameters->options().dynamic_list_data()
342       && !this->is_from_dynobj()
343       && this->type() == elfcpp::STT_OBJECT)
344     return true;
345
346   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
347   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
348   if ((parameters->options().dynamic_list_cpp_new()
349        || parameters->options().dynamic_list_cpp_typeinfo())
350       && !this->is_from_dynobj())
351     {
352       // TODO(csilvers): We could probably figure out if we're an operator
353       //                 new/delete or typeinfo without the need to demangle.
354       char* demangled_name = cplus_demangle(this->name(),
355                                             DMGL_ANSI | DMGL_PARAMS);
356       if (demangled_name == NULL)
357         {
358           // Not a C++ symbol, so it can't satisfy these flags
359         }
360       else if (parameters->options().dynamic_list_cpp_new()
361                && (strprefix(demangled_name, "operator new")
362                    || strprefix(demangled_name, "operator delete")))
363         {
364           free(demangled_name);
365           return true;
366         }
367       else if (parameters->options().dynamic_list_cpp_typeinfo()
368                && (strprefix(demangled_name, "typeinfo name for")
369                    || strprefix(demangled_name, "typeinfo for")))
370         {
371           free(demangled_name);
372           return true;
373         }
374       else
375         free(demangled_name);
376     }
377
378   // If exporting all symbols or building a shared library,
379   // and the symbol is defined in a regular object and is
380   // externally visible, we need to add it.
381   if ((parameters->options().export_dynamic() || parameters->options().shared())
382       && !this->is_from_dynobj()
383       && this->is_externally_visible())
384     return true;
385
386   return false;
387 }
388
389 // Return true if the final value of this symbol is known at link
390 // time.
391
392 bool
393 Symbol::final_value_is_known() const
394 {
395   // If we are not generating an executable, then no final values are
396   // known, since they will change at runtime.
397   if (parameters->options().shared() || 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()
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 DEF is true, then this is the definition of a default version of
816 // a symbol.  That means that any lookup of NAME/NULL and any lookup
817 // of NAME/VERSION should always return the same symbol.  This is
818 // obvious for references, but in particular we want to do this for
819 // definitions: overriding NAME/NULL should also override
820 // NAME/VERSION.  If we don't do that, it would be very hard to
821 // 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 def,
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> insdef =
886     std::make_pair(this->table_.end(), false);
887   if (def)
888     {
889       const Stringpool::Key vnull_key = 0;
890       insdef = 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 (def)
918         this->define_default_version<size, big_endian>(ret, insdef.second,
919                                                        insdef.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 (def && !insdef.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>(insdef.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 (!def)
958                     this->table_.erase(ins.first);
959                   else
960                     {
961                       this->table_.erase(insdef.first);
962                       // Inserting insdef 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 (def)
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(insdef.second);
978               insdef.first->second = ret;
979             }
980         }
981
982       if (def)
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_WEAK)
1013       && !parameters->options().relocatable())
1014     this->force_local(ret);
1015
1016   return ret;
1017 }
1018
1019 // Add all the symbols in a relocatable object to the hash table.
1020
1021 template<int size, bool big_endian>
1022 void
1023 Symbol_table::add_from_relobj(
1024     Sized_relobj<size, big_endian>* relobj,
1025     const unsigned char* syms,
1026     size_t count,
1027     size_t symndx_offset,
1028     const char* sym_names,
1029     size_t sym_name_size,
1030     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1031     size_t *defined)
1032 {
1033   *defined = 0;
1034
1035   gold_assert(size == parameters->target().get_size());
1036
1037   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1038
1039   const bool just_symbols = relobj->just_symbols();
1040
1041   const unsigned char* p = syms;
1042   for (size_t i = 0; i < count; ++i, p += sym_size)
1043     {
1044       (*sympointers)[i] = NULL;
1045
1046       elfcpp::Sym<size, big_endian> sym(p);
1047
1048       unsigned int st_name = sym.get_st_name();
1049       if (st_name >= sym_name_size)
1050         {
1051           relobj->error(_("bad global symbol name offset %u at %zu"),
1052                         st_name, i);
1053           continue;
1054         }
1055
1056       const char* name = sym_names + st_name;
1057
1058       bool is_ordinary;
1059       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1060                                                        sym.get_st_shndx(),
1061                                                        &is_ordinary);
1062       unsigned int orig_st_shndx = st_shndx;
1063       if (!is_ordinary)
1064         orig_st_shndx = elfcpp::SHN_UNDEF;
1065
1066       if (st_shndx != elfcpp::SHN_UNDEF)
1067         ++*defined;
1068
1069       // A symbol defined in a section which we are not including must
1070       // be treated as an undefined symbol.
1071       if (st_shndx != elfcpp::SHN_UNDEF
1072           && is_ordinary
1073           && !relobj->is_section_included(st_shndx))
1074         st_shndx = elfcpp::SHN_UNDEF;
1075
1076       // In an object file, an '@' in the name separates the symbol
1077       // name from the version name.  If there are two '@' characters,
1078       // this is the default version.
1079       const char* ver = strchr(name, '@');
1080       Stringpool::Key ver_key = 0;
1081       int namelen = 0;
1082       // DEF: is the version default?  LOCAL: is the symbol forced local?
1083       bool def = false;
1084       bool local = false;
1085
1086       if (ver != NULL)
1087         {
1088           // The symbol name is of the form foo@VERSION or foo@@VERSION
1089           namelen = ver - name;
1090           ++ver;
1091           if (*ver == '@')
1092             {
1093               def = true;
1094               ++ver;
1095             }
1096           ver = this->namepool_.add(ver, true, &ver_key);
1097         }
1098       // We don't want to assign a version to an undefined symbol,
1099       // even if it is listed in the version script.  FIXME: What
1100       // about a common symbol?
1101       else
1102         {
1103           namelen = strlen(name);
1104           if (!this->version_script_.empty()
1105               && st_shndx != elfcpp::SHN_UNDEF)
1106             {
1107               // The symbol name did not have a version, but the
1108               // version script may assign a version anyway.
1109               std::string version;
1110               if (this->version_script_.get_symbol_version(name, &version))
1111                 {
1112                   // The version can be empty if the version script is
1113                   // only used to force some symbols to be local.
1114                   if (!version.empty())
1115                     {
1116                       ver = this->namepool_.add_with_length(version.c_str(),
1117                                                             version.length(),
1118                                                             true,
1119                                                             &ver_key);
1120                       def = true;
1121                     }
1122                 }
1123               else if (this->version_script_.symbol_is_local(name))
1124                 local = true;
1125             }
1126         }
1127
1128       elfcpp::Sym<size, big_endian>* psym = &sym;
1129       unsigned char symbuf[sym_size];
1130       elfcpp::Sym<size, big_endian> sym2(symbuf);
1131       if (just_symbols)
1132         {
1133           memcpy(symbuf, p, sym_size);
1134           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1135           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1136             {
1137               // Symbol values in object files are section relative.
1138               // This is normally what we want, but since here we are
1139               // converting the symbol to absolute we need to add the
1140               // section address.  The section address in an object
1141               // file is normally zero, but people can use a linker
1142               // script to change it.
1143               sw.put_st_value(sym.get_st_value()
1144                               + relobj->section_address(orig_st_shndx));
1145             }
1146           st_shndx = elfcpp::SHN_ABS;
1147           is_ordinary = false;
1148           psym = &sym2;
1149         }
1150
1151       // Fix up visibility if object has no-export set.
1152       if (relobj->no_export())
1153         {
1154           // We may have copied symbol already above.
1155           if (psym != &sym2)
1156             {
1157               memcpy(symbuf, p, sym_size);
1158               psym = &sym2;
1159             }
1160
1161           elfcpp::STV visibility = sym2.get_st_visibility();
1162           if (visibility == elfcpp::STV_DEFAULT
1163               || visibility == elfcpp::STV_PROTECTED)
1164             {
1165               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1166               unsigned char nonvis = sym2.get_st_nonvis();
1167               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1168             }
1169         }
1170
1171       Stringpool::Key name_key;
1172       name = this->namepool_.add_with_length(name, namelen, true,
1173                                              &name_key);
1174
1175       Sized_symbol<size>* res;
1176       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1177                                   def, *psym, st_shndx, is_ordinary,
1178                                   orig_st_shndx);
1179       
1180       // If building a shared library using garbage collection, do not 
1181       // treat externally visible symbols as garbage.
1182       if (parameters->options().gc_sections() 
1183           && parameters->options().shared())
1184         this->gc_mark_symbol_for_shlib(res);
1185
1186       if (local)
1187         this->force_local(res);
1188
1189       (*sympointers)[i] = res;
1190     }
1191 }
1192
1193 // Add a symbol from a plugin-claimed file.
1194
1195 template<int size, bool big_endian>
1196 Symbol*
1197 Symbol_table::add_from_pluginobj(
1198     Sized_pluginobj<size, big_endian>* obj,
1199     const char* name,
1200     const char* ver,
1201     elfcpp::Sym<size, big_endian>* sym)
1202 {
1203   unsigned int st_shndx = sym->get_st_shndx();
1204
1205   Stringpool::Key ver_key = 0;
1206   bool def = false;
1207   bool local = false;
1208
1209   if (ver != NULL)
1210     {
1211       ver = this->namepool_.add(ver, true, &ver_key);
1212     }
1213   // We don't want to assign a version to an undefined symbol,
1214   // even if it is listed in the version script.  FIXME: What
1215   // about a common symbol?
1216   else
1217     {
1218       if (!this->version_script_.empty()
1219           && st_shndx != elfcpp::SHN_UNDEF)
1220         {
1221           // The symbol name did not have a version, but the
1222           // version script may assign a version anyway.
1223           std::string version;
1224           if (this->version_script_.get_symbol_version(name, &version))
1225             {
1226               // The version can be empty if the version script is
1227               // only used to force some symbols to be local.
1228               if (!version.empty())
1229                 {
1230                   ver = this->namepool_.add_with_length(version.c_str(),
1231                                                         version.length(),
1232                                                         true,
1233                                                         &ver_key);
1234                   def = true;
1235                 }
1236             }
1237           else if (this->version_script_.symbol_is_local(name))
1238             local = true;
1239         }
1240     }
1241
1242   Stringpool::Key name_key;
1243   name = this->namepool_.add(name, true, &name_key);
1244
1245   Sized_symbol<size>* res;
1246   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1247                               def, *sym, st_shndx, true, st_shndx);
1248
1249   if (local)
1250     this->force_local(res);
1251
1252   return res;
1253 }
1254
1255 // Add all the symbols in a dynamic object to the hash table.
1256
1257 template<int size, bool big_endian>
1258 void
1259 Symbol_table::add_from_dynobj(
1260     Sized_dynobj<size, big_endian>* dynobj,
1261     const unsigned char* syms,
1262     size_t count,
1263     const char* sym_names,
1264     size_t sym_name_size,
1265     const unsigned char* versym,
1266     size_t versym_size,
1267     const std::vector<const char*>* version_map,
1268     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1269     size_t* defined)
1270 {
1271   *defined = 0;
1272
1273   gold_assert(size == parameters->target().get_size());
1274
1275   if (dynobj->just_symbols())
1276     {
1277       gold_error(_("--just-symbols does not make sense with a shared object"));
1278       return;
1279     }
1280
1281   if (versym != NULL && versym_size / 2 < count)
1282     {
1283       dynobj->error(_("too few symbol versions"));
1284       return;
1285     }
1286
1287   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1288
1289   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1290   // weak aliases.  This is necessary because if the dynamic object
1291   // provides the same variable under two names, one of which is a
1292   // weak definition, and the regular object refers to the weak
1293   // definition, we have to put both the weak definition and the
1294   // strong definition into the dynamic symbol table.  Given a weak
1295   // definition, the only way that we can find the corresponding
1296   // strong definition, if any, is to search the symbol table.
1297   std::vector<Sized_symbol<size>*> object_symbols;
1298
1299   const unsigned char* p = syms;
1300   const unsigned char* vs = versym;
1301   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1302     {
1303       elfcpp::Sym<size, big_endian> sym(p);
1304
1305       if (sympointers != NULL)
1306         (*sympointers)[i] = NULL;
1307
1308       // Ignore symbols with local binding or that have
1309       // internal or hidden visibility.
1310       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1311           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1312           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1313         continue;
1314
1315       // A protected symbol in a shared library must be treated as a
1316       // normal symbol when viewed from outside the shared library.
1317       // Implement this by overriding the visibility here.
1318       elfcpp::Sym<size, big_endian>* psym = &sym;
1319       unsigned char symbuf[sym_size];
1320       elfcpp::Sym<size, big_endian> sym2(symbuf);
1321       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1322         {
1323           memcpy(symbuf, p, sym_size);
1324           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1325           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1326           psym = &sym2;
1327         }
1328
1329       unsigned int st_name = psym->get_st_name();
1330       if (st_name >= sym_name_size)
1331         {
1332           dynobj->error(_("bad symbol name offset %u at %zu"),
1333                         st_name, i);
1334           continue;
1335         }
1336
1337       const char* name = sym_names + st_name;
1338
1339       bool is_ordinary;
1340       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1341                                                        &is_ordinary);
1342
1343       if (st_shndx != elfcpp::SHN_UNDEF)
1344         ++*defined;
1345
1346       Sized_symbol<size>* res;
1347
1348       if (versym == NULL)
1349         {
1350           Stringpool::Key name_key;
1351           name = this->namepool_.add(name, true, &name_key);
1352           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1353                                       false, *psym, st_shndx, is_ordinary,
1354                                       st_shndx);
1355         }
1356       else
1357         {
1358           // Read the version information.
1359
1360           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1361
1362           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1363           v &= elfcpp::VERSYM_VERSION;
1364
1365           // The Sun documentation says that V can be VER_NDX_LOCAL,
1366           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1367           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1368           // The old GNU linker will happily generate VER_NDX_LOCAL
1369           // for an undefined symbol.  I don't know what the Sun
1370           // linker will generate.
1371
1372           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1373               && st_shndx != elfcpp::SHN_UNDEF)
1374             {
1375               // This symbol should not be visible outside the object.
1376               continue;
1377             }
1378
1379           // At this point we are definitely going to add this symbol.
1380           Stringpool::Key name_key;
1381           name = this->namepool_.add(name, true, &name_key);
1382
1383           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1384               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1385             {
1386               // This symbol does not have a version.
1387               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1388                                           false, *psym, st_shndx, is_ordinary,
1389                                           st_shndx);
1390             }
1391           else
1392             {
1393               if (v >= version_map->size())
1394                 {
1395                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1396                                 i, v);
1397                   continue;
1398                 }
1399
1400               const char* version = (*version_map)[v];
1401               if (version == NULL)
1402                 {
1403                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1404                                 i, v);
1405                   continue;
1406                 }
1407
1408               Stringpool::Key version_key;
1409               version = this->namepool_.add(version, true, &version_key);
1410
1411               // If this is an absolute symbol, and the version name
1412               // and symbol name are the same, then this is the
1413               // version definition symbol.  These symbols exist to
1414               // support using -u to pull in particular versions.  We
1415               // do not want to record a version for them.
1416               if (st_shndx == elfcpp::SHN_ABS
1417                   && !is_ordinary
1418                   && name_key == version_key)
1419                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1420                                             false, *psym, st_shndx, is_ordinary,
1421                                             st_shndx);
1422               else
1423                 {
1424                   const bool def = (!hidden
1425                                     && st_shndx != elfcpp::SHN_UNDEF);
1426                   res = this->add_from_object(dynobj, name, name_key, version,
1427                                               version_key, def, *psym, st_shndx,
1428                                               is_ordinary, st_shndx);
1429                 }
1430             }
1431         }
1432
1433       // Note that it is possible that RES was overridden by an
1434       // earlier object, in which case it can't be aliased here.
1435       if (st_shndx != elfcpp::SHN_UNDEF
1436           && is_ordinary
1437           && psym->get_st_type() == elfcpp::STT_OBJECT
1438           && res->source() == Symbol::FROM_OBJECT
1439           && res->object() == dynobj)
1440         object_symbols.push_back(res);
1441
1442       if (sympointers != NULL)
1443         (*sympointers)[i] = res;
1444     }
1445
1446   this->record_weak_aliases(&object_symbols);
1447 }
1448
1449 // This is used to sort weak aliases.  We sort them first by section
1450 // index, then by offset, then by weak ahead of strong.
1451
1452 template<int size>
1453 class Weak_alias_sorter
1454 {
1455  public:
1456   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1457 };
1458
1459 template<int size>
1460 bool
1461 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1462                                     const Sized_symbol<size>* s2) const
1463 {
1464   bool is_ordinary;
1465   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1466   gold_assert(is_ordinary);
1467   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1468   gold_assert(is_ordinary);
1469   if (s1_shndx != s2_shndx)
1470     return s1_shndx < s2_shndx;
1471
1472   if (s1->value() != s2->value())
1473     return s1->value() < s2->value();
1474   if (s1->binding() != s2->binding())
1475     {
1476       if (s1->binding() == elfcpp::STB_WEAK)
1477         return true;
1478       if (s2->binding() == elfcpp::STB_WEAK)
1479         return false;
1480     }
1481   return std::string(s1->name()) < std::string(s2->name());
1482 }
1483
1484 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1485 // for any weak aliases, and record them so that if we add the weak
1486 // alias to the dynamic symbol table, we also add the corresponding
1487 // strong symbol.
1488
1489 template<int size>
1490 void
1491 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1492 {
1493   // Sort the vector by section index, then by offset, then by weak
1494   // ahead of strong.
1495   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1496
1497   // Walk through the vector.  For each weak definition, record
1498   // aliases.
1499   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1500          symbols->begin();
1501        p != symbols->end();
1502        ++p)
1503     {
1504       if ((*p)->binding() != elfcpp::STB_WEAK)
1505         continue;
1506
1507       // Build a circular list of weak aliases.  Each symbol points to
1508       // the next one in the circular list.
1509
1510       Sized_symbol<size>* from_sym = *p;
1511       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1512       for (q = p + 1; q != symbols->end(); ++q)
1513         {
1514           bool dummy;
1515           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1516               || (*q)->value() != from_sym->value())
1517             break;
1518
1519           this->weak_aliases_[from_sym] = *q;
1520           from_sym->set_has_alias();
1521           from_sym = *q;
1522         }
1523
1524       if (from_sym != *p)
1525         {
1526           this->weak_aliases_[from_sym] = *p;
1527           from_sym->set_has_alias();
1528         }
1529
1530       p = q - 1;
1531     }
1532 }
1533
1534 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1535 // true, then only create the symbol if there is a reference to it.
1536 // If this does not return NULL, it sets *POLDSYM to the existing
1537 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1538 // resolve the newly created symbol to the old one.  This
1539 // canonicalizes *PNAME and *PVERSION.
1540
1541 template<int size, bool big_endian>
1542 Sized_symbol<size>*
1543 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1544                                     bool only_if_ref,
1545                                     Sized_symbol<size>** poldsym,
1546                                     bool *resolve_oldsym)
1547 {
1548   *resolve_oldsym = false;
1549
1550   // If the caller didn't give us a version, see if we get one from
1551   // the version script.
1552   std::string v;
1553   bool is_default_version = false;
1554   if (*pversion == NULL)
1555     {
1556       if (this->version_script_.get_symbol_version(*pname, &v))
1557         {
1558           if (!v.empty())
1559             *pversion = v.c_str();
1560
1561           // If we get the version from a version script, then we are
1562           // also the default version.
1563           is_default_version = true;
1564         }
1565     }
1566
1567   Symbol* oldsym;
1568   Sized_symbol<size>* sym;
1569
1570   bool add_to_table = false;
1571   typename Symbol_table_type::iterator add_loc = this->table_.end();
1572   bool add_def_to_table = false;
1573   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1574
1575   if (only_if_ref)
1576     {
1577       oldsym = this->lookup(*pname, *pversion);
1578       if (oldsym == NULL && is_default_version)
1579         oldsym = this->lookup(*pname, NULL);
1580       if (oldsym == NULL || !oldsym->is_undefined())
1581         return NULL;
1582
1583       *pname = oldsym->name();
1584       if (!is_default_version)
1585         *pversion = oldsym->version();
1586     }
1587   else
1588     {
1589       // Canonicalize NAME and VERSION.
1590       Stringpool::Key name_key;
1591       *pname = this->namepool_.add(*pname, true, &name_key);
1592
1593       Stringpool::Key version_key = 0;
1594       if (*pversion != NULL)
1595         *pversion = this->namepool_.add(*pversion, true, &version_key);
1596
1597       Symbol* const snull = NULL;
1598       std::pair<typename Symbol_table_type::iterator, bool> ins =
1599         this->table_.insert(std::make_pair(std::make_pair(name_key,
1600                                                           version_key),
1601                                            snull));
1602
1603       std::pair<typename Symbol_table_type::iterator, bool> insdef =
1604         std::make_pair(this->table_.end(), false);
1605       if (is_default_version)
1606         {
1607           const Stringpool::Key vnull = 0;
1608           insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
1609                                                                      vnull),
1610                                                       snull));
1611         }
1612
1613       if (!ins.second)
1614         {
1615           // We already have a symbol table entry for NAME/VERSION.
1616           oldsym = ins.first->second;
1617           gold_assert(oldsym != NULL);
1618
1619           if (is_default_version)
1620             {
1621               Sized_symbol<size>* soldsym =
1622                 this->get_sized_symbol<size>(oldsym);
1623               this->define_default_version<size, big_endian>(soldsym,
1624                                                              insdef.second,
1625                                                              insdef.first);
1626             }
1627         }
1628       else
1629         {
1630           // We haven't seen this symbol before.
1631           gold_assert(ins.first->second == NULL);
1632
1633           add_to_table = true;
1634           add_loc = ins.first;
1635
1636           if (is_default_version && !insdef.second)
1637             {
1638               // We are adding NAME/VERSION, and it is the default
1639               // version.  We already have an entry for NAME/NULL.
1640               oldsym = insdef.first->second;
1641               *resolve_oldsym = true;
1642             }
1643           else
1644             {
1645               oldsym = NULL;
1646
1647               if (is_default_version)
1648                 {
1649                   add_def_to_table = true;
1650                   add_def_loc = insdef.first;
1651                 }
1652             }
1653         }
1654     }
1655
1656   const Target& target = parameters->target();
1657   if (!target.has_make_symbol())
1658     sym = new Sized_symbol<size>();
1659   else
1660     {
1661       Sized_target<size, big_endian>* sized_target =
1662         parameters->sized_target<size, big_endian>();
1663       sym = sized_target->make_symbol();
1664       if (sym == NULL)
1665         return NULL;
1666     }
1667
1668   if (add_to_table)
1669     add_loc->second = sym;
1670   else
1671     gold_assert(oldsym != NULL);
1672
1673   if (add_def_to_table)
1674     add_def_loc->second = sym;
1675
1676   *poldsym = this->get_sized_symbol<size>(oldsym);
1677
1678   return sym;
1679 }
1680
1681 // Define a symbol based on an Output_data.
1682
1683 Symbol*
1684 Symbol_table::define_in_output_data(const char* name,
1685                                     const char* version,
1686                                     Output_data* od,
1687                                     uint64_t value,
1688                                     uint64_t symsize,
1689                                     elfcpp::STT type,
1690                                     elfcpp::STB binding,
1691                                     elfcpp::STV visibility,
1692                                     unsigned char nonvis,
1693                                     bool offset_is_from_end,
1694                                     bool only_if_ref)
1695 {
1696   if (parameters->target().get_size() == 32)
1697     {
1698 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1699       return this->do_define_in_output_data<32>(name, version, od,
1700                                                 value, symsize, type, binding,
1701                                                 visibility, nonvis,
1702                                                 offset_is_from_end,
1703                                                 only_if_ref);
1704 #else
1705       gold_unreachable();
1706 #endif
1707     }
1708   else if (parameters->target().get_size() == 64)
1709     {
1710 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1711       return this->do_define_in_output_data<64>(name, version, od,
1712                                                 value, symsize, type, binding,
1713                                                 visibility, nonvis,
1714                                                 offset_is_from_end,
1715                                                 only_if_ref);
1716 #else
1717       gold_unreachable();
1718 #endif
1719     }
1720   else
1721     gold_unreachable();
1722 }
1723
1724 // Define a symbol in an Output_data, sized version.
1725
1726 template<int size>
1727 Sized_symbol<size>*
1728 Symbol_table::do_define_in_output_data(
1729     const char* name,
1730     const char* version,
1731     Output_data* od,
1732     typename elfcpp::Elf_types<size>::Elf_Addr value,
1733     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1734     elfcpp::STT type,
1735     elfcpp::STB binding,
1736     elfcpp::STV visibility,
1737     unsigned char nonvis,
1738     bool offset_is_from_end,
1739     bool only_if_ref)
1740 {
1741   Sized_symbol<size>* sym;
1742   Sized_symbol<size>* oldsym;
1743   bool resolve_oldsym;
1744
1745   if (parameters->target().is_big_endian())
1746     {
1747 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1748       sym = this->define_special_symbol<size, true>(&name, &version,
1749                                                     only_if_ref, &oldsym,
1750                                                     &resolve_oldsym);
1751 #else
1752       gold_unreachable();
1753 #endif
1754     }
1755   else
1756     {
1757 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1758       sym = this->define_special_symbol<size, false>(&name, &version,
1759                                                      only_if_ref, &oldsym,
1760                                                      &resolve_oldsym);
1761 #else
1762       gold_unreachable();
1763 #endif
1764     }
1765
1766   if (sym == NULL)
1767     return NULL;
1768
1769   sym->init_output_data(name, version, od, value, symsize, type, binding,
1770                         visibility, nonvis, offset_is_from_end);
1771
1772   if (oldsym == NULL)
1773     {
1774       if (binding == elfcpp::STB_LOCAL
1775           || this->version_script_.symbol_is_local(name))
1776         this->force_local(sym);
1777       else if (version != NULL)
1778         sym->set_is_default();
1779       return sym;
1780     }
1781
1782   if (Symbol_table::should_override_with_special(oldsym))
1783     this->override_with_special(oldsym, sym);
1784
1785   if (resolve_oldsym)
1786     return sym;
1787   else
1788     {
1789       delete sym;
1790       return oldsym;
1791     }
1792 }
1793
1794 // Define a symbol based on an Output_segment.
1795
1796 Symbol*
1797 Symbol_table::define_in_output_segment(const char* name,
1798                                        const char* version, Output_segment* os,
1799                                        uint64_t value,
1800                                        uint64_t symsize,
1801                                        elfcpp::STT type,
1802                                        elfcpp::STB binding,
1803                                        elfcpp::STV visibility,
1804                                        unsigned char nonvis,
1805                                        Symbol::Segment_offset_base offset_base,
1806                                        bool only_if_ref)
1807 {
1808   if (parameters->target().get_size() == 32)
1809     {
1810 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1811       return this->do_define_in_output_segment<32>(name, version, os,
1812                                                    value, symsize, type,
1813                                                    binding, visibility, nonvis,
1814                                                    offset_base, only_if_ref);
1815 #else
1816       gold_unreachable();
1817 #endif
1818     }
1819   else if (parameters->target().get_size() == 64)
1820     {
1821 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1822       return this->do_define_in_output_segment<64>(name, version, os,
1823                                                    value, symsize, type,
1824                                                    binding, visibility, nonvis,
1825                                                    offset_base, only_if_ref);
1826 #else
1827       gold_unreachable();
1828 #endif
1829     }
1830   else
1831     gold_unreachable();
1832 }
1833
1834 // Define a symbol in an Output_segment, sized version.
1835
1836 template<int size>
1837 Sized_symbol<size>*
1838 Symbol_table::do_define_in_output_segment(
1839     const char* name,
1840     const char* version,
1841     Output_segment* os,
1842     typename elfcpp::Elf_types<size>::Elf_Addr value,
1843     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1844     elfcpp::STT type,
1845     elfcpp::STB binding,
1846     elfcpp::STV visibility,
1847     unsigned char nonvis,
1848     Symbol::Segment_offset_base offset_base,
1849     bool only_if_ref)
1850 {
1851   Sized_symbol<size>* sym;
1852   Sized_symbol<size>* oldsym;
1853   bool resolve_oldsym;
1854
1855   if (parameters->target().is_big_endian())
1856     {
1857 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1858       sym = this->define_special_symbol<size, true>(&name, &version,
1859                                                     only_if_ref, &oldsym,
1860                                                     &resolve_oldsym);
1861 #else
1862       gold_unreachable();
1863 #endif
1864     }
1865   else
1866     {
1867 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1868       sym = this->define_special_symbol<size, false>(&name, &version,
1869                                                      only_if_ref, &oldsym,
1870                                                      &resolve_oldsym);
1871 #else
1872       gold_unreachable();
1873 #endif
1874     }
1875
1876   if (sym == NULL)
1877     return NULL;
1878
1879   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1880                            visibility, nonvis, offset_base);
1881
1882   if (oldsym == NULL)
1883     {
1884       if (binding == elfcpp::STB_LOCAL
1885           || this->version_script_.symbol_is_local(name))
1886         this->force_local(sym);
1887       else if (version != NULL)
1888         sym->set_is_default();
1889       return sym;
1890     }
1891
1892   if (Symbol_table::should_override_with_special(oldsym))
1893     this->override_with_special(oldsym, sym);
1894
1895   if (resolve_oldsym)
1896     return sym;
1897   else
1898     {
1899       delete sym;
1900       return oldsym;
1901     }
1902 }
1903
1904 // Define a special symbol with a constant value.  It is a multiple
1905 // definition error if this symbol is already defined.
1906
1907 Symbol*
1908 Symbol_table::define_as_constant(const char* name,
1909                                  const char* version,
1910                                  uint64_t value,
1911                                  uint64_t symsize,
1912                                  elfcpp::STT type,
1913                                  elfcpp::STB binding,
1914                                  elfcpp::STV visibility,
1915                                  unsigned char nonvis,
1916                                  bool only_if_ref,
1917                                  bool force_override)
1918 {
1919   if (parameters->target().get_size() == 32)
1920     {
1921 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1922       return this->do_define_as_constant<32>(name, version, value,
1923                                              symsize, type, binding,
1924                                              visibility, nonvis, only_if_ref,
1925                                              force_override);
1926 #else
1927       gold_unreachable();
1928 #endif
1929     }
1930   else if (parameters->target().get_size() == 64)
1931     {
1932 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1933       return this->do_define_as_constant<64>(name, version, value,
1934                                              symsize, type, binding,
1935                                              visibility, nonvis, only_if_ref,
1936                                              force_override);
1937 #else
1938       gold_unreachable();
1939 #endif
1940     }
1941   else
1942     gold_unreachable();
1943 }
1944
1945 // Define a symbol as a constant, sized version.
1946
1947 template<int size>
1948 Sized_symbol<size>*
1949 Symbol_table::do_define_as_constant(
1950     const char* name,
1951     const char* version,
1952     typename elfcpp::Elf_types<size>::Elf_Addr value,
1953     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1954     elfcpp::STT type,
1955     elfcpp::STB binding,
1956     elfcpp::STV visibility,
1957     unsigned char nonvis,
1958     bool only_if_ref,
1959     bool force_override)
1960 {
1961   Sized_symbol<size>* sym;
1962   Sized_symbol<size>* oldsym;
1963   bool resolve_oldsym;
1964
1965   if (parameters->target().is_big_endian())
1966     {
1967 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1968       sym = this->define_special_symbol<size, true>(&name, &version,
1969                                                     only_if_ref, &oldsym,
1970                                                     &resolve_oldsym);
1971 #else
1972       gold_unreachable();
1973 #endif
1974     }
1975   else
1976     {
1977 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1978       sym = this->define_special_symbol<size, false>(&name, &version,
1979                                                      only_if_ref, &oldsym,
1980                                                      &resolve_oldsym);
1981 #else
1982       gold_unreachable();
1983 #endif
1984     }
1985
1986   if (sym == NULL)
1987     return NULL;
1988
1989   sym->init_constant(name, version, value, symsize, type, binding, visibility,
1990                      nonvis);
1991
1992   if (oldsym == NULL)
1993     {
1994       // Version symbols are absolute symbols with name == version.
1995       // We don't want to force them to be local.
1996       if ((version == NULL
1997            || name != version
1998            || value != 0)
1999           && (binding == elfcpp::STB_LOCAL
2000               || this->version_script_.symbol_is_local(name)))
2001         this->force_local(sym);
2002       else if (version != NULL
2003                && (name != version || value != 0))
2004         sym->set_is_default();
2005       return sym;
2006     }
2007
2008   if (force_override || Symbol_table::should_override_with_special(oldsym))
2009     this->override_with_special(oldsym, sym);
2010
2011   if (resolve_oldsym)
2012     return sym;
2013   else
2014     {
2015       delete sym;
2016       return oldsym;
2017     }
2018 }
2019
2020 // Define a set of symbols in output sections.
2021
2022 void
2023 Symbol_table::define_symbols(const Layout* layout, int count,
2024                              const Define_symbol_in_section* p,
2025                              bool only_if_ref)
2026 {
2027   for (int i = 0; i < count; ++i, ++p)
2028     {
2029       Output_section* os = layout->find_output_section(p->output_section);
2030       if (os != NULL)
2031         this->define_in_output_data(p->name, NULL, os, p->value,
2032                                     p->size, p->type, p->binding,
2033                                     p->visibility, p->nonvis,
2034                                     p->offset_is_from_end,
2035                                     only_if_ref || p->only_if_ref);
2036       else
2037         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2038                                  p->binding, p->visibility, p->nonvis,
2039                                  only_if_ref || p->only_if_ref,
2040                                  false);
2041     }
2042 }
2043
2044 // Define a set of symbols in output segments.
2045
2046 void
2047 Symbol_table::define_symbols(const Layout* layout, int count,
2048                              const Define_symbol_in_segment* p,
2049                              bool only_if_ref)
2050 {
2051   for (int i = 0; i < count; ++i, ++p)
2052     {
2053       Output_segment* os = layout->find_output_segment(p->segment_type,
2054                                                        p->segment_flags_set,
2055                                                        p->segment_flags_clear);
2056       if (os != NULL)
2057         this->define_in_output_segment(p->name, NULL, os, p->value,
2058                                        p->size, p->type, p->binding,
2059                                        p->visibility, p->nonvis,
2060                                        p->offset_base,
2061                                        only_if_ref || p->only_if_ref);
2062       else
2063         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2064                                  p->binding, p->visibility, p->nonvis,
2065                                  only_if_ref || p->only_if_ref,
2066                                  false);
2067     }
2068 }
2069
2070 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2071 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2072 // the offset within POSD.
2073
2074 template<int size>
2075 void
2076 Symbol_table::define_with_copy_reloc(
2077     Sized_symbol<size>* csym,
2078     Output_data* posd,
2079     typename elfcpp::Elf_types<size>::Elf_Addr value)
2080 {
2081   gold_assert(csym->is_from_dynobj());
2082   gold_assert(!csym->is_copied_from_dynobj());
2083   Object* object = csym->object();
2084   gold_assert(object->is_dynamic());
2085   Dynobj* dynobj = static_cast<Dynobj*>(object);
2086
2087   // Our copied variable has to override any variable in a shared
2088   // library.
2089   elfcpp::STB binding = csym->binding();
2090   if (binding == elfcpp::STB_WEAK)
2091     binding = elfcpp::STB_GLOBAL;
2092
2093   this->define_in_output_data(csym->name(), csym->version(),
2094                               posd, value, csym->symsize(),
2095                               csym->type(), binding,
2096                               csym->visibility(), csym->nonvis(),
2097                               false, false);
2098
2099   csym->set_is_copied_from_dynobj();
2100   csym->set_needs_dynsym_entry();
2101
2102   this->copied_symbol_dynobjs_[csym] = dynobj;
2103
2104   // We have now defined all aliases, but we have not entered them all
2105   // in the copied_symbol_dynobjs_ map.
2106   if (csym->has_alias())
2107     {
2108       Symbol* sym = csym;
2109       while (true)
2110         {
2111           sym = this->weak_aliases_[sym];
2112           if (sym == csym)
2113             break;
2114           gold_assert(sym->output_data() == posd);
2115
2116           sym->set_is_copied_from_dynobj();
2117           this->copied_symbol_dynobjs_[sym] = dynobj;
2118         }
2119     }
2120 }
2121
2122 // SYM is defined using a COPY reloc.  Return the dynamic object where
2123 // the original definition was found.
2124
2125 Dynobj*
2126 Symbol_table::get_copy_source(const Symbol* sym) const
2127 {
2128   gold_assert(sym->is_copied_from_dynobj());
2129   Copied_symbol_dynobjs::const_iterator p =
2130     this->copied_symbol_dynobjs_.find(sym);
2131   gold_assert(p != this->copied_symbol_dynobjs_.end());
2132   return p->second;
2133 }
2134
2135 // Add any undefined symbols named on the command line.
2136
2137 void
2138 Symbol_table::add_undefined_symbols_from_command_line()
2139 {
2140   if (parameters->options().any_undefined())
2141     {
2142       if (parameters->target().get_size() == 32)
2143         {
2144 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2145           this->do_add_undefined_symbols_from_command_line<32>();
2146 #else
2147           gold_unreachable();
2148 #endif
2149         }
2150       else if (parameters->target().get_size() == 64)
2151         {
2152 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2153           this->do_add_undefined_symbols_from_command_line<64>();
2154 #else
2155           gold_unreachable();
2156 #endif
2157         }
2158       else
2159         gold_unreachable();
2160     }
2161 }
2162
2163 template<int size>
2164 void
2165 Symbol_table::do_add_undefined_symbols_from_command_line()
2166 {
2167   for (options::String_set::const_iterator p =
2168          parameters->options().undefined_begin();
2169        p != parameters->options().undefined_end();
2170        ++p)
2171     {
2172       const char* name = p->c_str();
2173
2174       if (this->lookup(name) != NULL)
2175         continue;
2176
2177       const char* version = NULL;
2178
2179       Sized_symbol<size>* sym;
2180       Sized_symbol<size>* oldsym;
2181       bool resolve_oldsym;
2182       if (parameters->target().is_big_endian())
2183         {
2184 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2185           sym = this->define_special_symbol<size, true>(&name, &version,
2186                                                         false, &oldsym,
2187                                                         &resolve_oldsym);
2188 #else
2189           gold_unreachable();
2190 #endif
2191         }
2192       else
2193         {
2194 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2195           sym = this->define_special_symbol<size, false>(&name, &version,
2196                                                          false, &oldsym,
2197                                                          &resolve_oldsym);
2198 #else
2199           gold_unreachable();
2200 #endif
2201         }
2202
2203       gold_assert(oldsym == NULL);
2204
2205       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2206                           elfcpp::STV_DEFAULT, 0);
2207       ++this->saw_undefined_;
2208     }
2209 }
2210
2211 // Set the dynamic symbol indexes.  INDEX is the index of the first
2212 // global dynamic symbol.  Pointers to the symbols are stored into the
2213 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2214 // updated dynamic symbol index.
2215
2216 unsigned int
2217 Symbol_table::set_dynsym_indexes(unsigned int index,
2218                                  std::vector<Symbol*>* syms,
2219                                  Stringpool* dynpool,
2220                                  Versions* versions)
2221 {
2222   for (Symbol_table_type::iterator p = this->table_.begin();
2223        p != this->table_.end();
2224        ++p)
2225     {
2226       Symbol* sym = p->second;
2227
2228       // Note that SYM may already have a dynamic symbol index, since
2229       // some symbols appear more than once in the symbol table, with
2230       // and without a version.
2231
2232       if (!sym->should_add_dynsym_entry())
2233         sym->set_dynsym_index(-1U);
2234       else if (!sym->has_dynsym_index())
2235         {
2236           sym->set_dynsym_index(index);
2237           ++index;
2238           syms->push_back(sym);
2239           dynpool->add(sym->name(), false, NULL);
2240
2241           // Record any version information.
2242           if (sym->version() != NULL)
2243             versions->record_version(this, dynpool, sym);
2244         }
2245     }
2246
2247   // Finish up the versions.  In some cases this may add new dynamic
2248   // symbols.
2249   index = versions->finalize(this, index, syms);
2250
2251   return index;
2252 }
2253
2254 // Set the final values for all the symbols.  The index of the first
2255 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2256 // file offset OFF.  Add their names to POOL.  Return the new file
2257 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2258
2259 off_t
2260 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2261                        size_t dyncount, Stringpool* pool,
2262                        unsigned int *plocal_symcount)
2263 {
2264   off_t ret;
2265
2266   gold_assert(*plocal_symcount != 0);
2267   this->first_global_index_ = *plocal_symcount;
2268
2269   this->dynamic_offset_ = dynoff;
2270   this->first_dynamic_global_index_ = dyn_global_index;
2271   this->dynamic_count_ = dyncount;
2272
2273   if (parameters->target().get_size() == 32)
2274     {
2275 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2276       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2277 #else
2278       gold_unreachable();
2279 #endif
2280     }
2281   else if (parameters->target().get_size() == 64)
2282     {
2283 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2284       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2285 #else
2286       gold_unreachable();
2287 #endif
2288     }
2289   else
2290     gold_unreachable();
2291
2292   // Now that we have the final symbol table, we can reliably note
2293   // which symbols should get warnings.
2294   this->warnings_.note_warnings(this);
2295
2296   return ret;
2297 }
2298
2299 // SYM is going into the symbol table at *PINDEX.  Add the name to
2300 // POOL, update *PINDEX and *POFF.
2301
2302 template<int size>
2303 void
2304 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2305                                   unsigned int* pindex, off_t* poff)
2306 {
2307   sym->set_symtab_index(*pindex);
2308   pool->add(sym->name(), false, NULL);
2309   ++*pindex;
2310   *poff += elfcpp::Elf_sizes<size>::sym_size;
2311 }
2312
2313 // Set the final value for all the symbols.  This is called after
2314 // Layout::finalize, so all the output sections have their final
2315 // address.
2316
2317 template<int size>
2318 off_t
2319 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2320                              unsigned int* plocal_symcount)
2321 {
2322   off = align_address(off, size >> 3);
2323   this->offset_ = off;
2324
2325   unsigned int index = *plocal_symcount;
2326   const unsigned int orig_index = index;
2327
2328   // First do all the symbols which have been forced to be local, as
2329   // they must appear before all global symbols.
2330   for (Forced_locals::iterator p = this->forced_locals_.begin();
2331        p != this->forced_locals_.end();
2332        ++p)
2333     {
2334       Symbol* sym = *p;
2335       gold_assert(sym->is_forced_local());
2336       if (this->sized_finalize_symbol<size>(sym))
2337         {
2338           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2339           ++*plocal_symcount;
2340         }
2341     }
2342
2343   // Now do all the remaining symbols.
2344   for (Symbol_table_type::iterator p = this->table_.begin();
2345        p != this->table_.end();
2346        ++p)
2347     {
2348       Symbol* sym = p->second;
2349       if (this->sized_finalize_symbol<size>(sym))
2350         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2351     }
2352
2353   this->output_count_ = index - orig_index;
2354
2355   return off;
2356 }
2357
2358 // Compute the final value of SYM and store status in location PSTATUS.
2359 // During relaxation, this may be called multiple times for a symbol to
2360 // compute its would-be final value in each relaxation pass.
2361
2362 template<int size>
2363 typename Sized_symbol<size>::Value_type
2364 Symbol_table::compute_final_value(
2365     const Sized_symbol<size>* sym,
2366     Compute_final_value_status* pstatus) const
2367 {
2368   typedef typename Sized_symbol<size>::Value_type Value_type;
2369   Value_type value;
2370
2371   switch (sym->source())
2372     {
2373     case Symbol::FROM_OBJECT:
2374       {
2375         bool is_ordinary;
2376         unsigned int shndx = sym->shndx(&is_ordinary);
2377
2378         if (!is_ordinary
2379             && shndx != elfcpp::SHN_ABS
2380             && !Symbol::is_common_shndx(shndx))
2381           {
2382             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2383             return 0;
2384           }
2385
2386         Object* symobj = sym->object();
2387         if (symobj->is_dynamic())
2388           {
2389             value = 0;
2390             shndx = elfcpp::SHN_UNDEF;
2391           }
2392         else if (symobj->pluginobj() != NULL)
2393           {
2394             value = 0;
2395             shndx = elfcpp::SHN_UNDEF;
2396           }
2397         else if (shndx == elfcpp::SHN_UNDEF)
2398           value = 0;
2399         else if (!is_ordinary
2400                  && (shndx == elfcpp::SHN_ABS
2401                      || Symbol::is_common_shndx(shndx)))
2402           value = sym->value();
2403         else
2404           {
2405             Relobj* relobj = static_cast<Relobj*>(symobj);
2406             Output_section* os = relobj->output_section(shndx);
2407             uint64_t secoff64 = relobj->output_section_offset(shndx);
2408
2409             if (this->is_section_folded(relobj, shndx))
2410               {
2411                 gold_assert(os == NULL);
2412                 // Get the os of the section it is folded onto.
2413                 Section_id folded = this->icf_->get_folded_section(relobj,
2414                                                                    shndx);
2415                 gold_assert(folded.first != NULL);
2416                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2417                 os = folded_obj->output_section(folded.second);  
2418                 gold_assert(os != NULL);
2419                 secoff64 = folded_obj->output_section_offset(folded.second);
2420               }
2421
2422             if (os == NULL)
2423               {
2424                 bool static_or_reloc = (parameters->doing_static_link() ||
2425                                         parameters->options().relocatable());
2426                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2427
2428                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2429                 return 0;
2430               }
2431
2432             if (secoff64 == -1ULL)
2433               {
2434                 // The section needs special handling (e.g., a merge section).
2435
2436                 value = os->output_address(relobj, shndx, sym->value());
2437               }
2438             else
2439               {
2440                 Value_type secoff =
2441                   convert_types<Value_type, uint64_t>(secoff64);
2442                 if (sym->type() == elfcpp::STT_TLS)
2443                   value = sym->value() + os->tls_offset() + secoff;
2444                 else
2445                   value = sym->value() + os->address() + secoff;
2446               }
2447           }
2448       }
2449       break;
2450
2451     case Symbol::IN_OUTPUT_DATA:
2452       {
2453         Output_data* od = sym->output_data();
2454         value = sym->value();
2455         if (sym->type() != elfcpp::STT_TLS)
2456           value += od->address();
2457         else
2458           {
2459             Output_section* os = od->output_section();
2460             gold_assert(os != NULL);
2461             value += os->tls_offset() + (od->address() - os->address());
2462           }
2463         if (sym->offset_is_from_end())
2464           value += od->data_size();
2465       }
2466       break;
2467
2468     case Symbol::IN_OUTPUT_SEGMENT:
2469       {
2470         Output_segment* os = sym->output_segment();
2471         value = sym->value();
2472         if (sym->type() != elfcpp::STT_TLS)
2473           value += os->vaddr();
2474         switch (sym->offset_base())
2475           {
2476           case Symbol::SEGMENT_START:
2477             break;
2478           case Symbol::SEGMENT_END:
2479             value += os->memsz();
2480             break;
2481           case Symbol::SEGMENT_BSS:
2482             value += os->filesz();
2483             break;
2484           default:
2485             gold_unreachable();
2486           }
2487       }
2488       break;
2489
2490     case Symbol::IS_CONSTANT:
2491       value = sym->value();
2492       break;
2493
2494     case Symbol::IS_UNDEFINED:
2495       value = 0;
2496       break;
2497
2498     default:
2499       gold_unreachable();
2500     }
2501
2502   *pstatus = CFVS_OK;
2503   return value;
2504 }
2505
2506 // Finalize the symbol SYM.  This returns true if the symbol should be
2507 // added to the symbol table, false otherwise.
2508
2509 template<int size>
2510 bool
2511 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2512 {
2513   typedef typename Sized_symbol<size>::Value_type Value_type;
2514
2515   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2516
2517   // The default version of a symbol may appear twice in the symbol
2518   // table.  We only need to finalize it once.
2519   if (sym->has_symtab_index())
2520     return false;
2521
2522   if (!sym->in_reg())
2523     {
2524       gold_assert(!sym->has_symtab_index());
2525       sym->set_symtab_index(-1U);
2526       gold_assert(sym->dynsym_index() == -1U);
2527       return false;
2528     }
2529
2530   // Compute final symbol value.
2531   Compute_final_value_status status;
2532   Value_type value = this->compute_final_value(sym, &status);
2533
2534   switch (status)
2535     {
2536     case CFVS_OK:
2537       break;
2538     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2539       {
2540         bool is_ordinary;
2541         unsigned int shndx = sym->shndx(&is_ordinary);
2542         gold_error(_("%s: unsupported symbol section 0x%x"),
2543                    sym->demangled_name().c_str(), shndx);
2544       }
2545       break;
2546     case CFVS_NO_OUTPUT_SECTION:
2547       sym->set_symtab_index(-1U);
2548       return false;
2549     default:
2550       gold_unreachable();
2551     }
2552
2553   sym->set_value(value);
2554
2555   if (parameters->options().strip_all()
2556       || !parameters->options().should_retain_symbol(sym->name()))
2557     {
2558       sym->set_symtab_index(-1U);
2559       return false;
2560     }
2561
2562   return true;
2563 }
2564
2565 // Write out the global symbols.
2566
2567 void
2568 Symbol_table::write_globals(const Stringpool* sympool,
2569                             const Stringpool* dynpool,
2570                             Output_symtab_xindex* symtab_xindex,
2571                             Output_symtab_xindex* dynsym_xindex,
2572                             Output_file* of) const
2573 {
2574   switch (parameters->size_and_endianness())
2575     {
2576 #ifdef HAVE_TARGET_32_LITTLE
2577     case Parameters::TARGET_32_LITTLE:
2578       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2579                                            dynsym_xindex, of);
2580       break;
2581 #endif
2582 #ifdef HAVE_TARGET_32_BIG
2583     case Parameters::TARGET_32_BIG:
2584       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2585                                           dynsym_xindex, of);
2586       break;
2587 #endif
2588 #ifdef HAVE_TARGET_64_LITTLE
2589     case Parameters::TARGET_64_LITTLE:
2590       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2591                                            dynsym_xindex, of);
2592       break;
2593 #endif
2594 #ifdef HAVE_TARGET_64_BIG
2595     case Parameters::TARGET_64_BIG:
2596       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2597                                           dynsym_xindex, of);
2598       break;
2599 #endif
2600     default:
2601       gold_unreachable();
2602     }
2603 }
2604
2605 // Write out the global symbols.
2606
2607 template<int size, bool big_endian>
2608 void
2609 Symbol_table::sized_write_globals(const Stringpool* sympool,
2610                                   const Stringpool* dynpool,
2611                                   Output_symtab_xindex* symtab_xindex,
2612                                   Output_symtab_xindex* dynsym_xindex,
2613                                   Output_file* of) const
2614 {
2615   const Target& target = parameters->target();
2616
2617   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2618
2619   const unsigned int output_count = this->output_count_;
2620   const section_size_type oview_size = output_count * sym_size;
2621   const unsigned int first_global_index = this->first_global_index_;
2622   unsigned char* psyms;
2623   if (this->offset_ == 0 || output_count == 0)
2624     psyms = NULL;
2625   else
2626     psyms = of->get_output_view(this->offset_, oview_size);
2627
2628   const unsigned int dynamic_count = this->dynamic_count_;
2629   const section_size_type dynamic_size = dynamic_count * sym_size;
2630   const unsigned int first_dynamic_global_index =
2631     this->first_dynamic_global_index_;
2632   unsigned char* dynamic_view;
2633   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2634     dynamic_view = NULL;
2635   else
2636     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2637
2638   for (Symbol_table_type::const_iterator p = this->table_.begin();
2639        p != this->table_.end();
2640        ++p)
2641     {
2642       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2643
2644       // Possibly warn about unresolved symbols in shared libraries.
2645       this->warn_about_undefined_dynobj_symbol(sym);
2646
2647       unsigned int sym_index = sym->symtab_index();
2648       unsigned int dynsym_index;
2649       if (dynamic_view == NULL)
2650         dynsym_index = -1U;
2651       else
2652         dynsym_index = sym->dynsym_index();
2653
2654       if (sym_index == -1U && dynsym_index == -1U)
2655         {
2656           // This symbol is not included in the output file.
2657           continue;
2658         }
2659
2660       unsigned int shndx;
2661       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2662       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2663       switch (sym->source())
2664         {
2665         case Symbol::FROM_OBJECT:
2666           {
2667             bool is_ordinary;
2668             unsigned int in_shndx = sym->shndx(&is_ordinary);
2669
2670             if (!is_ordinary
2671                 && in_shndx != elfcpp::SHN_ABS
2672                 && !Symbol::is_common_shndx(in_shndx))
2673               {
2674                 gold_error(_("%s: unsupported symbol section 0x%x"),
2675                            sym->demangled_name().c_str(), in_shndx);
2676                 shndx = in_shndx;
2677               }
2678             else
2679               {
2680                 Object* symobj = sym->object();
2681                 if (symobj->is_dynamic())
2682                   {
2683                     if (sym->needs_dynsym_value())
2684                       dynsym_value = target.dynsym_value(sym);
2685                     shndx = elfcpp::SHN_UNDEF;
2686                   }
2687                 else if (symobj->pluginobj() != NULL)
2688                   shndx = elfcpp::SHN_UNDEF;
2689                 else if (in_shndx == elfcpp::SHN_UNDEF
2690                          || (!is_ordinary
2691                              && (in_shndx == elfcpp::SHN_ABS
2692                                  || Symbol::is_common_shndx(in_shndx))))
2693                   shndx = in_shndx;
2694                 else
2695                   {
2696                     Relobj* relobj = static_cast<Relobj*>(symobj);
2697                     Output_section* os = relobj->output_section(in_shndx);
2698                     if (this->is_section_folded(relobj, in_shndx))
2699                       {
2700                         // This global symbol must be written out even though
2701                         // it is folded.
2702                         // Get the os of the section it is folded onto.
2703                         Section_id folded =
2704                              this->icf_->get_folded_section(relobj, in_shndx);
2705                         gold_assert(folded.first !=NULL);
2706                         Relobj* folded_obj = 
2707                           reinterpret_cast<Relobj*>(folded.first);
2708                         os = folded_obj->output_section(folded.second);  
2709                         gold_assert(os != NULL);
2710                       }
2711                     gold_assert(os != NULL);
2712                     shndx = os->out_shndx();
2713
2714                     if (shndx >= elfcpp::SHN_LORESERVE)
2715                       {
2716                         if (sym_index != -1U)
2717                           symtab_xindex->add(sym_index, shndx);
2718                         if (dynsym_index != -1U)
2719                           dynsym_xindex->add(dynsym_index, shndx);
2720                         shndx = elfcpp::SHN_XINDEX;
2721                       }
2722
2723                     // In object files symbol values are section
2724                     // relative.
2725                     if (parameters->options().relocatable())
2726                       sym_value -= os->address();
2727                   }
2728               }
2729           }
2730           break;
2731
2732         case Symbol::IN_OUTPUT_DATA:
2733           shndx = sym->output_data()->out_shndx();
2734           if (shndx >= elfcpp::SHN_LORESERVE)
2735             {
2736               if (sym_index != -1U)
2737                 symtab_xindex->add(sym_index, shndx);
2738               if (dynsym_index != -1U)
2739                 dynsym_xindex->add(dynsym_index, shndx);
2740               shndx = elfcpp::SHN_XINDEX;
2741             }
2742           break;
2743
2744         case Symbol::IN_OUTPUT_SEGMENT:
2745           shndx = elfcpp::SHN_ABS;
2746           break;
2747
2748         case Symbol::IS_CONSTANT:
2749           shndx = elfcpp::SHN_ABS;
2750           break;
2751
2752         case Symbol::IS_UNDEFINED:
2753           shndx = elfcpp::SHN_UNDEF;
2754           break;
2755
2756         default:
2757           gold_unreachable();
2758         }
2759
2760       if (sym_index != -1U)
2761         {
2762           sym_index -= first_global_index;
2763           gold_assert(sym_index < output_count);
2764           unsigned char* ps = psyms + (sym_index * sym_size);
2765           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2766                                                      sympool, ps);
2767         }
2768
2769       if (dynsym_index != -1U)
2770         {
2771           dynsym_index -= first_dynamic_global_index;
2772           gold_assert(dynsym_index < dynamic_count);
2773           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2774           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2775                                                      dynpool, pd);
2776         }
2777     }
2778
2779   of->write_output_view(this->offset_, oview_size, psyms);
2780   if (dynamic_view != NULL)
2781     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2782 }
2783
2784 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2785 // strtab holding the name.
2786
2787 template<int size, bool big_endian>
2788 void
2789 Symbol_table::sized_write_symbol(
2790     Sized_symbol<size>* sym,
2791     typename elfcpp::Elf_types<size>::Elf_Addr value,
2792     unsigned int shndx,
2793     const Stringpool* pool,
2794     unsigned char* p) const
2795 {
2796   elfcpp::Sym_write<size, big_endian> osym(p);
2797   osym.put_st_name(pool->get_offset(sym->name()));
2798   osym.put_st_value(value);
2799   // Use a symbol size of zero for undefined symbols from shared libraries.
2800   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2801     osym.put_st_size(0);
2802   else
2803     osym.put_st_size(sym->symsize());
2804   // A version script may have overridden the default binding.
2805   if (sym->is_forced_local())
2806     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, sym->type()));
2807   else
2808     osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type()));
2809   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2810   osym.put_st_shndx(shndx);
2811 }
2812
2813 // Check for unresolved symbols in shared libraries.  This is
2814 // controlled by the --allow-shlib-undefined option.
2815
2816 // We only warn about libraries for which we have seen all the
2817 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2818 // which were not seen in this link.  If we didn't see a DT_NEEDED
2819 // entry, we aren't going to be able to reliably report whether the
2820 // symbol is undefined.
2821
2822 // We also don't warn about libraries found in a system library
2823 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2824 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2825 // can have undefined references satisfied by ld-linux.so.
2826
2827 inline void
2828 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2829 {
2830   bool dummy;
2831   if (sym->source() == Symbol::FROM_OBJECT
2832       && sym->object()->is_dynamic()
2833       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2834       && sym->binding() != elfcpp::STB_WEAK
2835       && !parameters->options().allow_shlib_undefined()
2836       && !parameters->target().is_defined_by_abi(sym)
2837       && !sym->object()->is_in_system_directory())
2838     {
2839       // A very ugly cast.
2840       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2841       if (!dynobj->has_unknown_needed_entries())
2842         gold_undefined_symbol(sym);
2843     }
2844 }
2845
2846 // Write out a section symbol.  Return the update offset.
2847
2848 void
2849 Symbol_table::write_section_symbol(const Output_section *os,
2850                                    Output_symtab_xindex* symtab_xindex,
2851                                    Output_file* of,
2852                                    off_t offset) const
2853 {
2854   switch (parameters->size_and_endianness())
2855     {
2856 #ifdef HAVE_TARGET_32_LITTLE
2857     case Parameters::TARGET_32_LITTLE:
2858       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2859                                                   offset);
2860       break;
2861 #endif
2862 #ifdef HAVE_TARGET_32_BIG
2863     case Parameters::TARGET_32_BIG:
2864       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2865                                                  offset);
2866       break;
2867 #endif
2868 #ifdef HAVE_TARGET_64_LITTLE
2869     case Parameters::TARGET_64_LITTLE:
2870       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2871                                                   offset);
2872       break;
2873 #endif
2874 #ifdef HAVE_TARGET_64_BIG
2875     case Parameters::TARGET_64_BIG:
2876       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2877                                                  offset);
2878       break;
2879 #endif
2880     default:
2881       gold_unreachable();
2882     }
2883 }
2884
2885 // Write out a section symbol, specialized for size and endianness.
2886
2887 template<int size, bool big_endian>
2888 void
2889 Symbol_table::sized_write_section_symbol(const Output_section* os,
2890                                          Output_symtab_xindex* symtab_xindex,
2891                                          Output_file* of,
2892                                          off_t offset) const
2893 {
2894   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2895
2896   unsigned char* pov = of->get_output_view(offset, sym_size);
2897
2898   elfcpp::Sym_write<size, big_endian> osym(pov);
2899   osym.put_st_name(0);
2900   if (parameters->options().relocatable())
2901     osym.put_st_value(0);
2902   else
2903     osym.put_st_value(os->address());
2904   osym.put_st_size(0);
2905   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2906                                        elfcpp::STT_SECTION));
2907   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2908
2909   unsigned int shndx = os->out_shndx();
2910   if (shndx >= elfcpp::SHN_LORESERVE)
2911     {
2912       symtab_xindex->add(os->symtab_index(), shndx);
2913       shndx = elfcpp::SHN_XINDEX;
2914     }
2915   osym.put_st_shndx(shndx);
2916
2917   of->write_output_view(offset, sym_size, pov);
2918 }
2919
2920 // Print statistical information to stderr.  This is used for --stats.
2921
2922 void
2923 Symbol_table::print_stats() const
2924 {
2925 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2926   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2927           program_name, this->table_.size(), this->table_.bucket_count());
2928 #else
2929   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2930           program_name, this->table_.size());
2931 #endif
2932   this->namepool_.print_stats("symbol table stringpool");
2933 }
2934
2935 // We check for ODR violations by looking for symbols with the same
2936 // name for which the debugging information reports that they were
2937 // defined in different source locations.  When comparing the source
2938 // location, we consider instances with the same base filename and
2939 // line number to be the same.  This is because different object
2940 // files/shared libraries can include the same header file using
2941 // different paths, and we don't want to report an ODR violation in
2942 // that case.
2943
2944 // This struct is used to compare line information, as returned by
2945 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2946 // operator used with std::set.
2947
2948 struct Odr_violation_compare
2949 {
2950   bool
2951   operator()(const std::string& s1, const std::string& s2) const
2952   {
2953     std::string::size_type pos1 = s1.rfind('/');
2954     std::string::size_type pos2 = s2.rfind('/');
2955     if (pos1 == std::string::npos
2956         || pos2 == std::string::npos)
2957       return s1 < s2;
2958     return s1.compare(pos1, std::string::npos,
2959                       s2, pos2, std::string::npos) < 0;
2960   }
2961 };
2962
2963 // Check candidate_odr_violations_ to find symbols with the same name
2964 // but apparently different definitions (different source-file/line-no).
2965
2966 void
2967 Symbol_table::detect_odr_violations(const Task* task,
2968                                     const char* output_file_name) const
2969 {
2970   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2971        it != candidate_odr_violations_.end();
2972        ++it)
2973     {
2974       const char* symbol_name = it->first;
2975       // We use a sorted set so the output is deterministic.
2976       std::set<std::string, Odr_violation_compare> line_nums;
2977
2978       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
2979                locs = it->second.begin();
2980            locs != it->second.end();
2981            ++locs)
2982         {
2983           // We need to lock the object in order to read it.  This
2984           // means that we have to run in a singleton Task.  If we
2985           // want to run this in a general Task for better
2986           // performance, we will need one Task for object, plus
2987           // appropriate locking to ensure that we don't conflict with
2988           // other uses of the object.  Also note, one_addr2line is not
2989           // currently thread-safe.
2990           Task_lock_obj<Object> tl(task, locs->object);
2991           // 16 is the size of the object-cache that one_addr2line should use.
2992           std::string lineno = Dwarf_line_info::one_addr2line(
2993               locs->object, locs->shndx, locs->offset, 16);
2994           if (!lineno.empty())
2995             line_nums.insert(lineno);
2996         }
2997
2998       if (line_nums.size() > 1)
2999         {
3000           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3001                          "places (possible ODR violation):"),
3002                        output_file_name, demangle(symbol_name).c_str());
3003           for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3004                it2 != line_nums.end();
3005                ++it2)
3006             fprintf(stderr, "  %s\n", it2->c_str());
3007         }
3008     }
3009   // We only call one_addr2line() in this function, so we can clear its cache.
3010   Dwarf_line_info::clear_addr2line_cache();
3011 }
3012
3013 // Warnings functions.
3014
3015 // Add a new warning.
3016
3017 void
3018 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3019                       const std::string& warning)
3020 {
3021   name = symtab->canonicalize_name(name);
3022   this->warnings_[name].set(obj, warning);
3023 }
3024
3025 // Look through the warnings and mark the symbols for which we should
3026 // warn.  This is called during Layout::finalize when we know the
3027 // sources for all the symbols.
3028
3029 void
3030 Warnings::note_warnings(Symbol_table* symtab)
3031 {
3032   for (Warning_table::iterator p = this->warnings_.begin();
3033        p != this->warnings_.end();
3034        ++p)
3035     {
3036       Symbol* sym = symtab->lookup(p->first, NULL);
3037       if (sym != NULL
3038           && sym->source() == Symbol::FROM_OBJECT
3039           && sym->object() == p->second.object)
3040         sym->set_has_warning();
3041     }
3042 }
3043
3044 // Issue a warning.  This is called when we see a relocation against a
3045 // symbol for which has a warning.
3046
3047 template<int size, bool big_endian>
3048 void
3049 Warnings::issue_warning(const Symbol* sym,
3050                         const Relocate_info<size, big_endian>* relinfo,
3051                         size_t relnum, off_t reloffset) const
3052 {
3053   gold_assert(sym->has_warning());
3054   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3055   gold_assert(p != this->warnings_.end());
3056   gold_warning_at_location(relinfo, relnum, reloffset,
3057                            "%s", p->second.text.c_str());
3058 }
3059
3060 // Instantiate the templates we need.  We could use the configure
3061 // script to restrict this to only the ones needed for implemented
3062 // targets.
3063
3064 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3065 template
3066 void
3067 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3068 #endif
3069
3070 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3071 template
3072 void
3073 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3074 #endif
3075
3076 #ifdef HAVE_TARGET_32_LITTLE
3077 template
3078 void
3079 Symbol_table::add_from_relobj<32, false>(
3080     Sized_relobj<32, false>* relobj,
3081     const unsigned char* syms,
3082     size_t count,
3083     size_t symndx_offset,
3084     const char* sym_names,
3085     size_t sym_name_size,
3086     Sized_relobj<32, false>::Symbols* sympointers,
3087     size_t* defined);
3088 #endif
3089
3090 #ifdef HAVE_TARGET_32_BIG
3091 template
3092 void
3093 Symbol_table::add_from_relobj<32, true>(
3094     Sized_relobj<32, true>* relobj,
3095     const unsigned char* syms,
3096     size_t count,
3097     size_t symndx_offset,
3098     const char* sym_names,
3099     size_t sym_name_size,
3100     Sized_relobj<32, true>::Symbols* sympointers,
3101     size_t* defined);
3102 #endif
3103
3104 #ifdef HAVE_TARGET_64_LITTLE
3105 template
3106 void
3107 Symbol_table::add_from_relobj<64, false>(
3108     Sized_relobj<64, false>* relobj,
3109     const unsigned char* syms,
3110     size_t count,
3111     size_t symndx_offset,
3112     const char* sym_names,
3113     size_t sym_name_size,
3114     Sized_relobj<64, false>::Symbols* sympointers,
3115     size_t* defined);
3116 #endif
3117
3118 #ifdef HAVE_TARGET_64_BIG
3119 template
3120 void
3121 Symbol_table::add_from_relobj<64, true>(
3122     Sized_relobj<64, true>* relobj,
3123     const unsigned char* syms,
3124     size_t count,
3125     size_t symndx_offset,
3126     const char* sym_names,
3127     size_t sym_name_size,
3128     Sized_relobj<64, true>::Symbols* sympointers,
3129     size_t* defined);
3130 #endif
3131
3132 #ifdef HAVE_TARGET_32_LITTLE
3133 template
3134 Symbol*
3135 Symbol_table::add_from_pluginobj<32, false>(
3136     Sized_pluginobj<32, false>* obj,
3137     const char* name,
3138     const char* ver,
3139     elfcpp::Sym<32, false>* sym);
3140 #endif
3141
3142 #ifdef HAVE_TARGET_32_BIG
3143 template
3144 Symbol*
3145 Symbol_table::add_from_pluginobj<32, true>(
3146     Sized_pluginobj<32, true>* obj,
3147     const char* name,
3148     const char* ver,
3149     elfcpp::Sym<32, true>* sym);
3150 #endif
3151
3152 #ifdef HAVE_TARGET_64_LITTLE
3153 template
3154 Symbol*
3155 Symbol_table::add_from_pluginobj<64, false>(
3156     Sized_pluginobj<64, false>* obj,
3157     const char* name,
3158     const char* ver,
3159     elfcpp::Sym<64, false>* sym);
3160 #endif
3161
3162 #ifdef HAVE_TARGET_64_BIG
3163 template
3164 Symbol*
3165 Symbol_table::add_from_pluginobj<64, true>(
3166     Sized_pluginobj<64, true>* obj,
3167     const char* name,
3168     const char* ver,
3169     elfcpp::Sym<64, true>* sym);
3170 #endif
3171
3172 #ifdef HAVE_TARGET_32_LITTLE
3173 template
3174 void
3175 Symbol_table::add_from_dynobj<32, false>(
3176     Sized_dynobj<32, false>* dynobj,
3177     const unsigned char* syms,
3178     size_t count,
3179     const char* sym_names,
3180     size_t sym_name_size,
3181     const unsigned char* versym,
3182     size_t versym_size,
3183     const std::vector<const char*>* version_map,
3184     Sized_relobj<32, false>::Symbols* sympointers,
3185     size_t* defined);
3186 #endif
3187
3188 #ifdef HAVE_TARGET_32_BIG
3189 template
3190 void
3191 Symbol_table::add_from_dynobj<32, true>(
3192     Sized_dynobj<32, true>* dynobj,
3193     const unsigned char* syms,
3194     size_t count,
3195     const char* sym_names,
3196     size_t sym_name_size,
3197     const unsigned char* versym,
3198     size_t versym_size,
3199     const std::vector<const char*>* version_map,
3200     Sized_relobj<32, true>::Symbols* sympointers,
3201     size_t* defined);
3202 #endif
3203
3204 #ifdef HAVE_TARGET_64_LITTLE
3205 template
3206 void
3207 Symbol_table::add_from_dynobj<64, false>(
3208     Sized_dynobj<64, false>* dynobj,
3209     const unsigned char* syms,
3210     size_t count,
3211     const char* sym_names,
3212     size_t sym_name_size,
3213     const unsigned char* versym,
3214     size_t versym_size,
3215     const std::vector<const char*>* version_map,
3216     Sized_relobj<64, false>::Symbols* sympointers,
3217     size_t* defined);
3218 #endif
3219
3220 #ifdef HAVE_TARGET_64_BIG
3221 template
3222 void
3223 Symbol_table::add_from_dynobj<64, true>(
3224     Sized_dynobj<64, true>* dynobj,
3225     const unsigned char* syms,
3226     size_t count,
3227     const char* sym_names,
3228     size_t sym_name_size,
3229     const unsigned char* versym,
3230     size_t versym_size,
3231     const std::vector<const char*>* version_map,
3232     Sized_relobj<64, true>::Symbols* sympointers,
3233     size_t* defined);
3234 #endif
3235
3236 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3237 template
3238 void
3239 Symbol_table::define_with_copy_reloc<32>(
3240     Sized_symbol<32>* sym,
3241     Output_data* posd,
3242     elfcpp::Elf_types<32>::Elf_Addr value);
3243 #endif
3244
3245 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3246 template
3247 void
3248 Symbol_table::define_with_copy_reloc<64>(
3249     Sized_symbol<64>* sym,
3250     Output_data* posd,
3251     elfcpp::Elf_types<64>::Elf_Addr value);
3252 #endif
3253
3254 #ifdef HAVE_TARGET_32_LITTLE
3255 template
3256 void
3257 Warnings::issue_warning<32, false>(const Symbol* sym,
3258                                    const Relocate_info<32, false>* relinfo,
3259                                    size_t relnum, off_t reloffset) const;
3260 #endif
3261
3262 #ifdef HAVE_TARGET_32_BIG
3263 template
3264 void
3265 Warnings::issue_warning<32, true>(const Symbol* sym,
3266                                   const Relocate_info<32, true>* relinfo,
3267                                   size_t relnum, off_t reloffset) const;
3268 #endif
3269
3270 #ifdef HAVE_TARGET_64_LITTLE
3271 template
3272 void
3273 Warnings::issue_warning<64, false>(const Symbol* sym,
3274                                    const Relocate_info<64, false>* relinfo,
3275                                    size_t relnum, off_t reloffset) const;
3276 #endif
3277
3278 #ifdef HAVE_TARGET_64_BIG
3279 template
3280 void
3281 Warnings::issue_warning<64, true>(const Symbol* sym,
3282                                   const Relocate_info<64, true>* relinfo,
3283                                   size_t relnum, off_t reloffset) const;
3284 #endif
3285
3286 } // End namespace gold.