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1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <[email protected]>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
32
33 #include "gc.h"
34 #include "object.h"
35 #include "dwarf_reader.h"
36 #include "dynobj.h"
37 #include "output.h"
38 #include "target.h"
39 #include "workqueue.h"
40 #include "symtab.h"
41 #include "demangle.h"   // needed for --dynamic-list-cpp-new
42 #include "plugin.h"
43
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol.  This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54                     elfcpp::STT type, elfcpp::STB binding,
55                     elfcpp::STV visibility, unsigned char nonvis)
56 {
57   this->name_ = name;
58   this->version_ = version;
59   this->symtab_index_ = 0;
60   this->dynsym_index_ = 0;
61   this->got_offsets_.init();
62   this->plt_offset_ = 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().output_is_position_independent()
398       || parameters->options().relocatable())
399     return false;
400
401   // If the symbol is not from an object file, and is not undefined,
402   // then it is defined, and known.
403   if (this->source_ != FROM_OBJECT)
404     {
405       if (this->source_ != IS_UNDEFINED)
406         return true;
407     }
408   else
409     {
410       // If the symbol is from a dynamic object, then the final value
411       // is not known.
412       if (this->object()->is_dynamic())
413         return false;
414
415       // If the symbol is not undefined (it is defined or common),
416       // then the final value is known.
417       if (!this->is_undefined())
418         return true;
419     }
420
421   // If the symbol is undefined, then whether the final value is known
422   // depends on whether we are doing a static link.  If we are doing a
423   // dynamic link, then the final value could be filled in at runtime.
424   // This could reasonably be the case for a weak undefined symbol.
425   return parameters->doing_static_link();
426 }
427
428 // Return the output section where this symbol is defined.
429
430 Output_section*
431 Symbol::output_section() const
432 {
433   switch (this->source_)
434     {
435     case FROM_OBJECT:
436       {
437         unsigned int shndx = this->u_.from_object.shndx;
438         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
439           {
440             gold_assert(!this->u_.from_object.object->is_dynamic());
441             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
442             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
443             return relobj->output_section(shndx);
444           }
445         return NULL;
446       }
447
448     case IN_OUTPUT_DATA:
449       return this->u_.in_output_data.output_data->output_section();
450
451     case IN_OUTPUT_SEGMENT:
452     case IS_CONSTANT:
453     case IS_UNDEFINED:
454       return NULL;
455
456     default:
457       gold_unreachable();
458     }
459 }
460
461 // Set the symbol's output section.  This is used for symbols defined
462 // in scripts.  This should only be called after the symbol table has
463 // been finalized.
464
465 void
466 Symbol::set_output_section(Output_section* os)
467 {
468   switch (this->source_)
469     {
470     case FROM_OBJECT:
471     case IN_OUTPUT_DATA:
472       gold_assert(this->output_section() == os);
473       break;
474     case IS_CONSTANT:
475       this->source_ = IN_OUTPUT_DATA;
476       this->u_.in_output_data.output_data = os;
477       this->u_.in_output_data.offset_is_from_end = false;
478       break;
479     case IN_OUTPUT_SEGMENT:
480     case IS_UNDEFINED:
481     default:
482       gold_unreachable();
483     }
484 }
485
486 // Class Symbol_table.
487
488 Symbol_table::Symbol_table(unsigned int count,
489                            const Version_script_info& version_script)
490   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
491     forwarders_(), commons_(), tls_commons_(), small_commons_(),
492     large_commons_(), forced_locals_(), warnings_(),
493     version_script_(version_script), gc_(NULL), icf_(NULL)
494 {
495   namepool_.reserve(count);
496 }
497
498 Symbol_table::~Symbol_table()
499 {
500 }
501
502 // The hash function.  The key values are Stringpool keys.
503
504 inline size_t
505 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
506 {
507   return key.first ^ key.second;
508 }
509
510 // The symbol table key equality function.  This is called with
511 // Stringpool keys.
512
513 inline bool
514 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
515                                           const Symbol_table_key& k2) const
516 {
517   return k1.first == k2.first && k1.second == k2.second;
518 }
519
520 bool
521 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
522 {
523   return (parameters->options().icf_enabled()
524           && this->icf_->is_section_folded(obj, shndx));
525 }
526
527 // For symbols that have been listed with -u option, add them to the
528 // work list to avoid gc'ing them.
529
530 void 
531 Symbol_table::gc_mark_undef_symbols()
532 {
533   for (options::String_set::const_iterator p =
534          parameters->options().undefined_begin();
535        p != parameters->options().undefined_end();
536        ++p)
537     {
538       const char* name = p->c_str();
539       Symbol* sym = this->lookup(name);
540       gold_assert (sym != NULL);
541       if (sym->source() == Symbol::FROM_OBJECT 
542           && !sym->object()->is_dynamic())
543         {
544           Relobj* obj = static_cast<Relobj*>(sym->object());
545           bool is_ordinary;
546           unsigned int shndx = sym->shndx(&is_ordinary);
547           if (is_ordinary)
548             {
549               gold_assert(this->gc_ != NULL);
550               this->gc_->worklist().push(Section_id(obj, shndx));
551             }
552         }
553     }
554 }
555
556 void
557 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
558 {
559   if (!sym->is_from_dynobj() 
560       && sym->is_externally_visible())
561     {
562       //Add the object and section to the work list.
563       Relobj* obj = static_cast<Relobj*>(sym->object());
564       bool is_ordinary;
565       unsigned int shndx = sym->shndx(&is_ordinary);
566       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
567         {
568           gold_assert(this->gc_!= NULL);
569           this->gc_->worklist().push(Section_id(obj, shndx));
570         }
571     }
572 }
573
574 // When doing garbage collection, keep symbols that have been seen in
575 // dynamic objects.
576 inline void 
577 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
578 {
579   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
580       && !sym->object()->is_dynamic())
581     {
582       Relobj *obj = static_cast<Relobj*>(sym->object()); 
583       bool is_ordinary;
584       unsigned int shndx = sym->shndx(&is_ordinary);
585       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
586         {
587           gold_assert(this->gc_ != NULL);
588           this->gc_->worklist().push(Section_id(obj, shndx));
589         }
590     }
591 }
592
593 // Make TO a symbol which forwards to FROM.
594
595 void
596 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
597 {
598   gold_assert(from != to);
599   gold_assert(!from->is_forwarder() && !to->is_forwarder());
600   this->forwarders_[from] = to;
601   from->set_forwarder();
602 }
603
604 // Resolve the forwards from FROM, returning the real symbol.
605
606 Symbol*
607 Symbol_table::resolve_forwards(const Symbol* from) const
608 {
609   gold_assert(from->is_forwarder());
610   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
611     this->forwarders_.find(from);
612   gold_assert(p != this->forwarders_.end());
613   return p->second;
614 }
615
616 // Look up a symbol by name.
617
618 Symbol*
619 Symbol_table::lookup(const char* name, const char* version) const
620 {
621   Stringpool::Key name_key;
622   name = this->namepool_.find(name, &name_key);
623   if (name == NULL)
624     return NULL;
625
626   Stringpool::Key version_key = 0;
627   if (version != NULL)
628     {
629       version = this->namepool_.find(version, &version_key);
630       if (version == NULL)
631         return NULL;
632     }
633
634   Symbol_table_key key(name_key, version_key);
635   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
636   if (p == this->table_.end())
637     return NULL;
638   return p->second;
639 }
640
641 // Resolve a Symbol with another Symbol.  This is only used in the
642 // unusual case where there are references to both an unversioned
643 // symbol and a symbol with a version, and we then discover that that
644 // version is the default version.  Because this is unusual, we do
645 // this the slow way, by converting back to an ELF symbol.
646
647 template<int size, bool big_endian>
648 void
649 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
650 {
651   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
652   elfcpp::Sym_write<size, big_endian> esym(buf);
653   // We don't bother to set the st_name or the st_shndx field.
654   esym.put_st_value(from->value());
655   esym.put_st_size(from->symsize());
656   esym.put_st_info(from->binding(), from->type());
657   esym.put_st_other(from->visibility(), from->nonvis());
658   bool is_ordinary;
659   unsigned int shndx = from->shndx(&is_ordinary);
660   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
661                 from->version());
662   if (from->in_reg())
663     to->set_in_reg();
664   if (from->in_dyn())
665     to->set_in_dyn();
666   if (parameters->options().gc_sections())
667     this->gc_mark_dyn_syms(to);
668 }
669
670 // Record that a symbol is forced to be local by a version script or
671 // by visibility.
672
673 void
674 Symbol_table::force_local(Symbol* sym)
675 {
676   if (!sym->is_defined() && !sym->is_common())
677     return;
678   if (sym->is_forced_local())
679     {
680       // We already got this one.
681       return;
682     }
683   sym->set_is_forced_local();
684   this->forced_locals_.push_back(sym);
685 }
686
687 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
688 // is only called for undefined symbols, when at least one --wrap
689 // option was used.
690
691 const char*
692 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
693 {
694   // For some targets, we need to ignore a specific character when
695   // wrapping, and add it back later.
696   char prefix = '\0';
697   if (name[0] == parameters->target().wrap_char())
698     {
699       prefix = name[0];
700       ++name;
701     }
702
703   if (parameters->options().is_wrap(name))
704     {
705       // Turn NAME into __wrap_NAME.
706       std::string s;
707       if (prefix != '\0')
708         s += prefix;
709       s += "__wrap_";
710       s += name;
711
712       // This will give us both the old and new name in NAMEPOOL_, but
713       // that is OK.  Only the versions we need will wind up in the
714       // real string table in the output file.
715       return this->namepool_.add(s.c_str(), true, name_key);
716     }
717
718   const char* const real_prefix = "__real_";
719   const size_t real_prefix_length = strlen(real_prefix);
720   if (strncmp(name, real_prefix, real_prefix_length) == 0
721       && parameters->options().is_wrap(name + real_prefix_length))
722     {
723       // Turn __real_NAME into NAME.
724       std::string s;
725       if (prefix != '\0')
726         s += prefix;
727       s += name + real_prefix_length;
728       return this->namepool_.add(s.c_str(), true, name_key);
729     }
730
731   return name;
732 }
733
734 // This is called when we see a symbol NAME/VERSION, and the symbol
735 // already exists in the symbol table, and VERSION is marked as being
736 // the default version.  SYM is the NAME/VERSION symbol we just added.
737 // DEFAULT_IS_NEW is true if this is the first time we have seen the
738 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
739
740 template<int size, bool big_endian>
741 void
742 Symbol_table::define_default_version(Sized_symbol<size>* sym,
743                                      bool default_is_new,
744                                      Symbol_table_type::iterator pdef)
745 {
746   if (default_is_new)
747     {
748       // This is the first time we have seen NAME/NULL.  Make
749       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
750       // version.
751       pdef->second = sym;
752       sym->set_is_default();
753     }
754   else if (pdef->second == sym)
755     {
756       // NAME/NULL already points to NAME/VERSION.  Don't mark the
757       // symbol as the default if it is not already the default.
758     }
759   else
760     {
761       // This is the unfortunate case where we already have entries
762       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
763       // NAME/VERSION where VERSION is the default version.  We have
764       // already resolved this new symbol with the existing
765       // NAME/VERSION symbol.
766
767       // It's possible that NAME/NULL and NAME/VERSION are both
768       // defined in regular objects.  This can only happen if one
769       // object file defines foo and another defines foo@@ver.  This
770       // is somewhat obscure, but we call it a multiple definition
771       // error.
772
773       // It's possible that NAME/NULL actually has a version, in which
774       // case it won't be the same as VERSION.  This happens with
775       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
776       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
777       // then see an unadorned t2_2 in an object file and give it
778       // version VER1 from the version script.  This looks like a
779       // default definition for VER1, so it looks like we should merge
780       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
781       // not obvious that this is an error, either.  So we just punt.
782
783       // If one of the symbols has non-default visibility, and the
784       // other is defined in a shared object, then they are different
785       // symbols.
786
787       // Otherwise, we just resolve the symbols as though they were
788       // the same.
789
790       if (pdef->second->version() != NULL)
791         gold_assert(pdef->second->version() != sym->version());
792       else if (sym->visibility() != elfcpp::STV_DEFAULT
793                && pdef->second->is_from_dynobj())
794         ;
795       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
796                && sym->is_from_dynobj())
797         ;
798       else
799         {
800           const Sized_symbol<size>* symdef;
801           symdef = this->get_sized_symbol<size>(pdef->second);
802           Symbol_table::resolve<size, big_endian>(sym, symdef);
803           this->make_forwarder(pdef->second, sym);
804           pdef->second = sym;
805           sym->set_is_default();
806         }
807     }
808 }
809
810 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
811 // name and VERSION is the version; both are canonicalized.  DEF is
812 // whether this is the default version.  ST_SHNDX is the symbol's
813 // section index; IS_ORDINARY is whether this is a normal section
814 // rather than a special code.
815
816 // If DEF is true, then this is the definition of a default version of
817 // a symbol.  That means that any lookup of NAME/NULL and any lookup
818 // of NAME/VERSION should always return the same symbol.  This is
819 // obvious for references, but in particular we want to do this for
820 // definitions: overriding NAME/NULL should also override
821 // NAME/VERSION.  If we don't do that, it would be very hard to
822 // override functions in a shared library which uses versioning.
823
824 // We implement this by simply making both entries in the hash table
825 // point to the same Symbol structure.  That is easy enough if this is
826 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
827 // that we have seen both already, in which case they will both have
828 // independent entries in the symbol table.  We can't simply change
829 // the symbol table entry, because we have pointers to the entries
830 // attached to the object files.  So we mark the entry attached to the
831 // object file as a forwarder, and record it in the forwarders_ map.
832 // Note that entries in the hash table will never be marked as
833 // forwarders.
834 //
835 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
836 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
837 // for a special section code.  ST_SHNDX may be modified if the symbol
838 // is defined in a section being discarded.
839
840 template<int size, bool big_endian>
841 Sized_symbol<size>*
842 Symbol_table::add_from_object(Object* object,
843                               const char *name,
844                               Stringpool::Key name_key,
845                               const char *version,
846                               Stringpool::Key version_key,
847                               bool def,
848                               const elfcpp::Sym<size, big_endian>& sym,
849                               unsigned int st_shndx,
850                               bool is_ordinary,
851                               unsigned int orig_st_shndx)
852 {
853   // Print a message if this symbol is being traced.
854   if (parameters->options().is_trace_symbol(name))
855     {
856       if (orig_st_shndx == elfcpp::SHN_UNDEF)
857         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
858       else
859         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
860     }
861
862   // For an undefined symbol, we may need to adjust the name using
863   // --wrap.
864   if (orig_st_shndx == elfcpp::SHN_UNDEF
865       && parameters->options().any_wrap())
866     {
867       const char* wrap_name = this->wrap_symbol(name, &name_key);
868       if (wrap_name != name)
869         {
870           // If we see a reference to malloc with version GLIBC_2.0,
871           // and we turn it into a reference to __wrap_malloc, then we
872           // discard the version number.  Otherwise the user would be
873           // required to specify the correct version for
874           // __wrap_malloc.
875           version = NULL;
876           version_key = 0;
877           name = wrap_name;
878         }
879     }
880
881   Symbol* const snull = NULL;
882   std::pair<typename Symbol_table_type::iterator, bool> ins =
883     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
884                                        snull));
885
886   std::pair<typename Symbol_table_type::iterator, bool> insdef =
887     std::make_pair(this->table_.end(), false);
888   if (def)
889     {
890       const Stringpool::Key vnull_key = 0;
891       insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
892                                                                  vnull_key),
893                                                   snull));
894     }
895
896   // ins.first: an iterator, which is a pointer to a pair.
897   // ins.first->first: the key (a pair of name and version).
898   // ins.first->second: the value (Symbol*).
899   // ins.second: true if new entry was inserted, false if not.
900
901   Sized_symbol<size>* ret;
902   bool was_undefined;
903   bool was_common;
904   if (!ins.second)
905     {
906       // We already have an entry for NAME/VERSION.
907       ret = this->get_sized_symbol<size>(ins.first->second);
908       gold_assert(ret != NULL);
909
910       was_undefined = ret->is_undefined();
911       was_common = ret->is_common();
912
913       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
914                     version);
915       if (parameters->options().gc_sections())
916         this->gc_mark_dyn_syms(ret);
917
918       if (def)
919         this->define_default_version<size, big_endian>(ret, insdef.second,
920                                                        insdef.first);
921     }
922   else
923     {
924       // This is the first time we have seen NAME/VERSION.
925       gold_assert(ins.first->second == NULL);
926
927       if (def && !insdef.second)
928         {
929           // We already have an entry for NAME/NULL.  If we override
930           // it, then change it to NAME/VERSION.
931           ret = this->get_sized_symbol<size>(insdef.first->second);
932
933           was_undefined = ret->is_undefined();
934           was_common = ret->is_common();
935
936           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
937                         version);
938           if (parameters->options().gc_sections())
939             this->gc_mark_dyn_syms(ret);
940           ins.first->second = ret;
941         }
942       else
943         {
944           was_undefined = false;
945           was_common = false;
946
947           Sized_target<size, big_endian>* target =
948             parameters->sized_target<size, big_endian>();
949           if (!target->has_make_symbol())
950             ret = new Sized_symbol<size>();
951           else
952             {
953               ret = target->make_symbol();
954               if (ret == NULL)
955                 {
956                   // This means that we don't want a symbol table
957                   // entry after all.
958                   if (!def)
959                     this->table_.erase(ins.first);
960                   else
961                     {
962                       this->table_.erase(insdef.first);
963                       // Inserting insdef invalidated ins.
964                       this->table_.erase(std::make_pair(name_key,
965                                                         version_key));
966                     }
967                   return NULL;
968                 }
969             }
970
971           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
972
973           ins.first->second = ret;
974           if (def)
975             {
976               // This is the first time we have seen NAME/NULL.  Point
977               // it at the new entry for NAME/VERSION.
978               gold_assert(insdef.second);
979               insdef.first->second = ret;
980             }
981         }
982
983       if (def)
984         ret->set_is_default();
985     }
986
987   // Record every time we see a new undefined symbol, to speed up
988   // archive groups.
989   if (!was_undefined && ret->is_undefined())
990     ++this->saw_undefined_;
991
992   // Keep track of common symbols, to speed up common symbol
993   // allocation.
994   if (!was_common && ret->is_common())
995     {
996       if (ret->type() == elfcpp::STT_TLS)
997         this->tls_commons_.push_back(ret);
998       else if (!is_ordinary
999                && st_shndx == parameters->target().small_common_shndx())
1000         this->small_commons_.push_back(ret);
1001       else if (!is_ordinary
1002                && st_shndx == parameters->target().large_common_shndx())
1003         this->large_commons_.push_back(ret);
1004       else
1005         this->commons_.push_back(ret);
1006     }
1007
1008   // If we're not doing a relocatable link, then any symbol with
1009   // hidden or internal visibility is local.
1010   if ((ret->visibility() == elfcpp::STV_HIDDEN
1011        || ret->visibility() == elfcpp::STV_INTERNAL)
1012       && (ret->binding() == elfcpp::STB_GLOBAL
1013           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1014           || ret->binding() == elfcpp::STB_WEAK)
1015       && !parameters->options().relocatable())
1016     this->force_local(ret);
1017
1018   return ret;
1019 }
1020
1021 // Add all the symbols in a relocatable object to the hash table.
1022
1023 template<int size, bool big_endian>
1024 void
1025 Symbol_table::add_from_relobj(
1026     Sized_relobj<size, big_endian>* relobj,
1027     const unsigned char* syms,
1028     size_t count,
1029     size_t symndx_offset,
1030     const char* sym_names,
1031     size_t sym_name_size,
1032     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1033     size_t *defined)
1034 {
1035   *defined = 0;
1036
1037   gold_assert(size == parameters->target().get_size());
1038
1039   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1040
1041   const bool just_symbols = relobj->just_symbols();
1042
1043   const unsigned char* p = syms;
1044   for (size_t i = 0; i < count; ++i, p += sym_size)
1045     {
1046       (*sympointers)[i] = NULL;
1047
1048       elfcpp::Sym<size, big_endian> sym(p);
1049
1050       unsigned int st_name = sym.get_st_name();
1051       if (st_name >= sym_name_size)
1052         {
1053           relobj->error(_("bad global symbol name offset %u at %zu"),
1054                         st_name, i);
1055           continue;
1056         }
1057
1058       const char* name = sym_names + st_name;
1059
1060       bool is_ordinary;
1061       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1062                                                        sym.get_st_shndx(),
1063                                                        &is_ordinary);
1064       unsigned int orig_st_shndx = st_shndx;
1065       if (!is_ordinary)
1066         orig_st_shndx = elfcpp::SHN_UNDEF;
1067
1068       if (st_shndx != elfcpp::SHN_UNDEF)
1069         ++*defined;
1070
1071       // A symbol defined in a section which we are not including must
1072       // be treated as an undefined symbol.
1073       if (st_shndx != elfcpp::SHN_UNDEF
1074           && is_ordinary
1075           && !relobj->is_section_included(st_shndx))
1076         st_shndx = elfcpp::SHN_UNDEF;
1077
1078       // In an object file, an '@' in the name separates the symbol
1079       // name from the version name.  If there are two '@' characters,
1080       // this is the default version.
1081       const char* ver = strchr(name, '@');
1082       Stringpool::Key ver_key = 0;
1083       int namelen = 0;
1084       // DEF: is the version default?  LOCAL: is the symbol forced local?
1085       bool def = false;
1086       bool local = false;
1087
1088       if (ver != NULL)
1089         {
1090           // The symbol name is of the form foo@VERSION or foo@@VERSION
1091           namelen = ver - name;
1092           ++ver;
1093           if (*ver == '@')
1094             {
1095               def = true;
1096               ++ver;
1097             }
1098           ver = this->namepool_.add(ver, true, &ver_key);
1099         }
1100       // We don't want to assign a version to an undefined symbol,
1101       // even if it is listed in the version script.  FIXME: What
1102       // about a common symbol?
1103       else
1104         {
1105           namelen = strlen(name);
1106           if (!this->version_script_.empty()
1107               && st_shndx != elfcpp::SHN_UNDEF)
1108             {
1109               // The symbol name did not have a version, but the
1110               // version script may assign a version anyway.
1111               std::string version;
1112               if (this->version_script_.get_symbol_version(name, &version))
1113                 {
1114                   // The version can be empty if the version script is
1115                   // only used to force some symbols to be local.
1116                   if (!version.empty())
1117                     {
1118                       ver = this->namepool_.add_with_length(version.c_str(),
1119                                                             version.length(),
1120                                                             true,
1121                                                             &ver_key);
1122                       def = true;
1123                     }
1124                 }
1125               else if (this->version_script_.symbol_is_local(name))
1126                 local = true;
1127             }
1128         }
1129
1130       elfcpp::Sym<size, big_endian>* psym = &sym;
1131       unsigned char symbuf[sym_size];
1132       elfcpp::Sym<size, big_endian> sym2(symbuf);
1133       if (just_symbols)
1134         {
1135           memcpy(symbuf, p, sym_size);
1136           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1137           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1138             {
1139               // Symbol values in object files are section relative.
1140               // This is normally what we want, but since here we are
1141               // converting the symbol to absolute we need to add the
1142               // section address.  The section address in an object
1143               // file is normally zero, but people can use a linker
1144               // script to change it.
1145               sw.put_st_value(sym.get_st_value()
1146                               + relobj->section_address(orig_st_shndx));
1147             }
1148           st_shndx = elfcpp::SHN_ABS;
1149           is_ordinary = false;
1150           psym = &sym2;
1151         }
1152
1153       // Fix up visibility if object has no-export set.
1154       if (relobj->no_export())
1155         {
1156           // We may have copied symbol already above.
1157           if (psym != &sym2)
1158             {
1159               memcpy(symbuf, p, sym_size);
1160               psym = &sym2;
1161             }
1162
1163           elfcpp::STV visibility = sym2.get_st_visibility();
1164           if (visibility == elfcpp::STV_DEFAULT
1165               || visibility == elfcpp::STV_PROTECTED)
1166             {
1167               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1168               unsigned char nonvis = sym2.get_st_nonvis();
1169               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1170             }
1171         }
1172
1173       Stringpool::Key name_key;
1174       name = this->namepool_.add_with_length(name, namelen, true,
1175                                              &name_key);
1176
1177       Sized_symbol<size>* res;
1178       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1179                                   def, *psym, st_shndx, is_ordinary,
1180                                   orig_st_shndx);
1181       
1182       // If building a shared library using garbage collection, do not 
1183       // treat externally visible symbols as garbage.
1184       if (parameters->options().gc_sections() 
1185           && parameters->options().shared())
1186         this->gc_mark_symbol_for_shlib(res);
1187
1188       if (local)
1189         this->force_local(res);
1190
1191       (*sympointers)[i] = res;
1192     }
1193 }
1194
1195 // Add a symbol from a plugin-claimed file.
1196
1197 template<int size, bool big_endian>
1198 Symbol*
1199 Symbol_table::add_from_pluginobj(
1200     Sized_pluginobj<size, big_endian>* obj,
1201     const char* name,
1202     const char* ver,
1203     elfcpp::Sym<size, big_endian>* sym)
1204 {
1205   unsigned int st_shndx = sym->get_st_shndx();
1206   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1207
1208   Stringpool::Key ver_key = 0;
1209   bool def = false;
1210   bool local = false;
1211
1212   if (ver != NULL)
1213     {
1214       ver = this->namepool_.add(ver, true, &ver_key);
1215     }
1216   // We don't want to assign a version to an undefined symbol,
1217   // even if it is listed in the version script.  FIXME: What
1218   // about a common symbol?
1219   else
1220     {
1221       if (!this->version_script_.empty()
1222           && st_shndx != elfcpp::SHN_UNDEF)
1223         {
1224           // The symbol name did not have a version, but the
1225           // version script may assign a version anyway.
1226           std::string version;
1227           if (this->version_script_.get_symbol_version(name, &version))
1228             {
1229               // The version can be empty if the version script is
1230               // only used to force some symbols to be local.
1231               if (!version.empty())
1232                 {
1233                   ver = this->namepool_.add_with_length(version.c_str(),
1234                                                         version.length(),
1235                                                         true,
1236                                                         &ver_key);
1237                   def = true;
1238                 }
1239             }
1240           else if (this->version_script_.symbol_is_local(name))
1241             local = true;
1242         }
1243     }
1244
1245   Stringpool::Key name_key;
1246   name = this->namepool_.add(name, true, &name_key);
1247
1248   Sized_symbol<size>* res;
1249   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1250                               def, *sym, st_shndx, is_ordinary, st_shndx);
1251
1252   if (local)
1253     this->force_local(res);
1254
1255   return res;
1256 }
1257
1258 // Add all the symbols in a dynamic object to the hash table.
1259
1260 template<int size, bool big_endian>
1261 void
1262 Symbol_table::add_from_dynobj(
1263     Sized_dynobj<size, big_endian>* dynobj,
1264     const unsigned char* syms,
1265     size_t count,
1266     const char* sym_names,
1267     size_t sym_name_size,
1268     const unsigned char* versym,
1269     size_t versym_size,
1270     const std::vector<const char*>* version_map,
1271     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1272     size_t* defined)
1273 {
1274   *defined = 0;
1275
1276   gold_assert(size == parameters->target().get_size());
1277
1278   if (dynobj->just_symbols())
1279     {
1280       gold_error(_("--just-symbols does not make sense with a shared object"));
1281       return;
1282     }
1283
1284   if (versym != NULL && versym_size / 2 < count)
1285     {
1286       dynobj->error(_("too few symbol versions"));
1287       return;
1288     }
1289
1290   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1291
1292   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1293   // weak aliases.  This is necessary because if the dynamic object
1294   // provides the same variable under two names, one of which is a
1295   // weak definition, and the regular object refers to the weak
1296   // definition, we have to put both the weak definition and the
1297   // strong definition into the dynamic symbol table.  Given a weak
1298   // definition, the only way that we can find the corresponding
1299   // strong definition, if any, is to search the symbol table.
1300   std::vector<Sized_symbol<size>*> object_symbols;
1301
1302   const unsigned char* p = syms;
1303   const unsigned char* vs = versym;
1304   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1305     {
1306       elfcpp::Sym<size, big_endian> sym(p);
1307
1308       if (sympointers != NULL)
1309         (*sympointers)[i] = NULL;
1310
1311       // Ignore symbols with local binding or that have
1312       // internal or hidden visibility.
1313       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1314           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1315           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1316         continue;
1317
1318       // A protected symbol in a shared library must be treated as a
1319       // normal symbol when viewed from outside the shared library.
1320       // Implement this by overriding the visibility here.
1321       elfcpp::Sym<size, big_endian>* psym = &sym;
1322       unsigned char symbuf[sym_size];
1323       elfcpp::Sym<size, big_endian> sym2(symbuf);
1324       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1325         {
1326           memcpy(symbuf, p, sym_size);
1327           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1328           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1329           psym = &sym2;
1330         }
1331
1332       unsigned int st_name = psym->get_st_name();
1333       if (st_name >= sym_name_size)
1334         {
1335           dynobj->error(_("bad symbol name offset %u at %zu"),
1336                         st_name, i);
1337           continue;
1338         }
1339
1340       const char* name = sym_names + st_name;
1341
1342       bool is_ordinary;
1343       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1344                                                        &is_ordinary);
1345
1346       if (st_shndx != elfcpp::SHN_UNDEF)
1347         ++*defined;
1348
1349       Sized_symbol<size>* res;
1350
1351       if (versym == NULL)
1352         {
1353           Stringpool::Key name_key;
1354           name = this->namepool_.add(name, true, &name_key);
1355           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1356                                       false, *psym, st_shndx, is_ordinary,
1357                                       st_shndx);
1358         }
1359       else
1360         {
1361           // Read the version information.
1362
1363           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1364
1365           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1366           v &= elfcpp::VERSYM_VERSION;
1367
1368           // The Sun documentation says that V can be VER_NDX_LOCAL,
1369           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1370           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1371           // The old GNU linker will happily generate VER_NDX_LOCAL
1372           // for an undefined symbol.  I don't know what the Sun
1373           // linker will generate.
1374
1375           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1376               && st_shndx != elfcpp::SHN_UNDEF)
1377             {
1378               // This symbol should not be visible outside the object.
1379               continue;
1380             }
1381
1382           // At this point we are definitely going to add this symbol.
1383           Stringpool::Key name_key;
1384           name = this->namepool_.add(name, true, &name_key);
1385
1386           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1387               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1388             {
1389               // This symbol does not have a version.
1390               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1391                                           false, *psym, st_shndx, is_ordinary,
1392                                           st_shndx);
1393             }
1394           else
1395             {
1396               if (v >= version_map->size())
1397                 {
1398                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1399                                 i, v);
1400                   continue;
1401                 }
1402
1403               const char* version = (*version_map)[v];
1404               if (version == NULL)
1405                 {
1406                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1407                                 i, v);
1408                   continue;
1409                 }
1410
1411               Stringpool::Key version_key;
1412               version = this->namepool_.add(version, true, &version_key);
1413
1414               // If this is an absolute symbol, and the version name
1415               // and symbol name are the same, then this is the
1416               // version definition symbol.  These symbols exist to
1417               // support using -u to pull in particular versions.  We
1418               // do not want to record a version for them.
1419               if (st_shndx == elfcpp::SHN_ABS
1420                   && !is_ordinary
1421                   && name_key == version_key)
1422                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1423                                             false, *psym, st_shndx, is_ordinary,
1424                                             st_shndx);
1425               else
1426                 {
1427                   const bool def = (!hidden
1428                                     && st_shndx != elfcpp::SHN_UNDEF);
1429                   res = this->add_from_object(dynobj, name, name_key, version,
1430                                               version_key, def, *psym, st_shndx,
1431                                               is_ordinary, st_shndx);
1432                 }
1433             }
1434         }
1435
1436       // Note that it is possible that RES was overridden by an
1437       // earlier object, in which case it can't be aliased here.
1438       if (st_shndx != elfcpp::SHN_UNDEF
1439           && is_ordinary
1440           && psym->get_st_type() == elfcpp::STT_OBJECT
1441           && res->source() == Symbol::FROM_OBJECT
1442           && res->object() == dynobj)
1443         object_symbols.push_back(res);
1444
1445       if (sympointers != NULL)
1446         (*sympointers)[i] = res;
1447     }
1448
1449   this->record_weak_aliases(&object_symbols);
1450 }
1451
1452 // This is used to sort weak aliases.  We sort them first by section
1453 // index, then by offset, then by weak ahead of strong.
1454
1455 template<int size>
1456 class Weak_alias_sorter
1457 {
1458  public:
1459   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1460 };
1461
1462 template<int size>
1463 bool
1464 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1465                                     const Sized_symbol<size>* s2) const
1466 {
1467   bool is_ordinary;
1468   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1469   gold_assert(is_ordinary);
1470   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1471   gold_assert(is_ordinary);
1472   if (s1_shndx != s2_shndx)
1473     return s1_shndx < s2_shndx;
1474
1475   if (s1->value() != s2->value())
1476     return s1->value() < s2->value();
1477   if (s1->binding() != s2->binding())
1478     {
1479       if (s1->binding() == elfcpp::STB_WEAK)
1480         return true;
1481       if (s2->binding() == elfcpp::STB_WEAK)
1482         return false;
1483     }
1484   return std::string(s1->name()) < std::string(s2->name());
1485 }
1486
1487 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1488 // for any weak aliases, and record them so that if we add the weak
1489 // alias to the dynamic symbol table, we also add the corresponding
1490 // strong symbol.
1491
1492 template<int size>
1493 void
1494 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1495 {
1496   // Sort the vector by section index, then by offset, then by weak
1497   // ahead of strong.
1498   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1499
1500   // Walk through the vector.  For each weak definition, record
1501   // aliases.
1502   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1503          symbols->begin();
1504        p != symbols->end();
1505        ++p)
1506     {
1507       if ((*p)->binding() != elfcpp::STB_WEAK)
1508         continue;
1509
1510       // Build a circular list of weak aliases.  Each symbol points to
1511       // the next one in the circular list.
1512
1513       Sized_symbol<size>* from_sym = *p;
1514       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1515       for (q = p + 1; q != symbols->end(); ++q)
1516         {
1517           bool dummy;
1518           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1519               || (*q)->value() != from_sym->value())
1520             break;
1521
1522           this->weak_aliases_[from_sym] = *q;
1523           from_sym->set_has_alias();
1524           from_sym = *q;
1525         }
1526
1527       if (from_sym != *p)
1528         {
1529           this->weak_aliases_[from_sym] = *p;
1530           from_sym->set_has_alias();
1531         }
1532
1533       p = q - 1;
1534     }
1535 }
1536
1537 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1538 // true, then only create the symbol if there is a reference to it.
1539 // If this does not return NULL, it sets *POLDSYM to the existing
1540 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1541 // resolve the newly created symbol to the old one.  This
1542 // canonicalizes *PNAME and *PVERSION.
1543
1544 template<int size, bool big_endian>
1545 Sized_symbol<size>*
1546 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1547                                     bool only_if_ref,
1548                                     Sized_symbol<size>** poldsym,
1549                                     bool *resolve_oldsym)
1550 {
1551   *resolve_oldsym = false;
1552
1553   // If the caller didn't give us a version, see if we get one from
1554   // the version script.
1555   std::string v;
1556   bool is_default_version = false;
1557   if (*pversion == NULL)
1558     {
1559       if (this->version_script_.get_symbol_version(*pname, &v))
1560         {
1561           if (!v.empty())
1562             *pversion = v.c_str();
1563
1564           // If we get the version from a version script, then we are
1565           // also the default version.
1566           is_default_version = true;
1567         }
1568     }
1569
1570   Symbol* oldsym;
1571   Sized_symbol<size>* sym;
1572
1573   bool add_to_table = false;
1574   typename Symbol_table_type::iterator add_loc = this->table_.end();
1575   bool add_def_to_table = false;
1576   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1577
1578   if (only_if_ref)
1579     {
1580       oldsym = this->lookup(*pname, *pversion);
1581       if (oldsym == NULL && is_default_version)
1582         oldsym = this->lookup(*pname, NULL);
1583       if (oldsym == NULL || !oldsym->is_undefined())
1584         return NULL;
1585
1586       *pname = oldsym->name();
1587       if (!is_default_version)
1588         *pversion = oldsym->version();
1589     }
1590   else
1591     {
1592       // Canonicalize NAME and VERSION.
1593       Stringpool::Key name_key;
1594       *pname = this->namepool_.add(*pname, true, &name_key);
1595
1596       Stringpool::Key version_key = 0;
1597       if (*pversion != NULL)
1598         *pversion = this->namepool_.add(*pversion, true, &version_key);
1599
1600       Symbol* const snull = NULL;
1601       std::pair<typename Symbol_table_type::iterator, bool> ins =
1602         this->table_.insert(std::make_pair(std::make_pair(name_key,
1603                                                           version_key),
1604                                            snull));
1605
1606       std::pair<typename Symbol_table_type::iterator, bool> insdef =
1607         std::make_pair(this->table_.end(), false);
1608       if (is_default_version)
1609         {
1610           const Stringpool::Key vnull = 0;
1611           insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
1612                                                                      vnull),
1613                                                       snull));
1614         }
1615
1616       if (!ins.second)
1617         {
1618           // We already have a symbol table entry for NAME/VERSION.
1619           oldsym = ins.first->second;
1620           gold_assert(oldsym != NULL);
1621
1622           if (is_default_version)
1623             {
1624               Sized_symbol<size>* soldsym =
1625                 this->get_sized_symbol<size>(oldsym);
1626               this->define_default_version<size, big_endian>(soldsym,
1627                                                              insdef.second,
1628                                                              insdef.first);
1629             }
1630         }
1631       else
1632         {
1633           // We haven't seen this symbol before.
1634           gold_assert(ins.first->second == NULL);
1635
1636           add_to_table = true;
1637           add_loc = ins.first;
1638
1639           if (is_default_version && !insdef.second)
1640             {
1641               // We are adding NAME/VERSION, and it is the default
1642               // version.  We already have an entry for NAME/NULL.
1643               oldsym = insdef.first->second;
1644               *resolve_oldsym = true;
1645             }
1646           else
1647             {
1648               oldsym = NULL;
1649
1650               if (is_default_version)
1651                 {
1652                   add_def_to_table = true;
1653                   add_def_loc = insdef.first;
1654                 }
1655             }
1656         }
1657     }
1658
1659   const Target& target = parameters->target();
1660   if (!target.has_make_symbol())
1661     sym = new Sized_symbol<size>();
1662   else
1663     {
1664       Sized_target<size, big_endian>* sized_target =
1665         parameters->sized_target<size, big_endian>();
1666       sym = sized_target->make_symbol();
1667       if (sym == NULL)
1668         return NULL;
1669     }
1670
1671   if (add_to_table)
1672     add_loc->second = sym;
1673   else
1674     gold_assert(oldsym != NULL);
1675
1676   if (add_def_to_table)
1677     add_def_loc->second = sym;
1678
1679   *poldsym = this->get_sized_symbol<size>(oldsym);
1680
1681   return sym;
1682 }
1683
1684 // Define a symbol based on an Output_data.
1685
1686 Symbol*
1687 Symbol_table::define_in_output_data(const char* name,
1688                                     const char* version,
1689                                     Defined defined,
1690                                     Output_data* od,
1691                                     uint64_t value,
1692                                     uint64_t symsize,
1693                                     elfcpp::STT type,
1694                                     elfcpp::STB binding,
1695                                     elfcpp::STV visibility,
1696                                     unsigned char nonvis,
1697                                     bool offset_is_from_end,
1698                                     bool only_if_ref)
1699 {
1700   if (parameters->target().get_size() == 32)
1701     {
1702 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1703       return this->do_define_in_output_data<32>(name, version, defined, od,
1704                                                 value, symsize, type, binding,
1705                                                 visibility, nonvis,
1706                                                 offset_is_from_end,
1707                                                 only_if_ref);
1708 #else
1709       gold_unreachable();
1710 #endif
1711     }
1712   else if (parameters->target().get_size() == 64)
1713     {
1714 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1715       return this->do_define_in_output_data<64>(name, version, defined, od,
1716                                                 value, symsize, type, binding,
1717                                                 visibility, nonvis,
1718                                                 offset_is_from_end,
1719                                                 only_if_ref);
1720 #else
1721       gold_unreachable();
1722 #endif
1723     }
1724   else
1725     gold_unreachable();
1726 }
1727
1728 // Define a symbol in an Output_data, sized version.
1729
1730 template<int size>
1731 Sized_symbol<size>*
1732 Symbol_table::do_define_in_output_data(
1733     const char* name,
1734     const char* version,
1735     Defined defined,
1736     Output_data* od,
1737     typename elfcpp::Elf_types<size>::Elf_Addr value,
1738     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1739     elfcpp::STT type,
1740     elfcpp::STB binding,
1741     elfcpp::STV visibility,
1742     unsigned char nonvis,
1743     bool offset_is_from_end,
1744     bool only_if_ref)
1745 {
1746   Sized_symbol<size>* sym;
1747   Sized_symbol<size>* oldsym;
1748   bool resolve_oldsym;
1749
1750   if (parameters->target().is_big_endian())
1751     {
1752 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1753       sym = this->define_special_symbol<size, true>(&name, &version,
1754                                                     only_if_ref, &oldsym,
1755                                                     &resolve_oldsym);
1756 #else
1757       gold_unreachable();
1758 #endif
1759     }
1760   else
1761     {
1762 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1763       sym = this->define_special_symbol<size, false>(&name, &version,
1764                                                      only_if_ref, &oldsym,
1765                                                      &resolve_oldsym);
1766 #else
1767       gold_unreachable();
1768 #endif
1769     }
1770
1771   if (sym == NULL)
1772     return NULL;
1773
1774   sym->init_output_data(name, version, od, value, symsize, type, binding,
1775                         visibility, nonvis, offset_is_from_end);
1776
1777   if (oldsym == NULL)
1778     {
1779       if (binding == elfcpp::STB_LOCAL
1780           || this->version_script_.symbol_is_local(name))
1781         this->force_local(sym);
1782       else if (version != NULL)
1783         sym->set_is_default();
1784       return sym;
1785     }
1786
1787   if (Symbol_table::should_override_with_special(oldsym, defined))
1788     this->override_with_special(oldsym, sym);
1789
1790   if (resolve_oldsym)
1791     return sym;
1792   else
1793     {
1794       delete sym;
1795       return oldsym;
1796     }
1797 }
1798
1799 // Define a symbol based on an Output_segment.
1800
1801 Symbol*
1802 Symbol_table::define_in_output_segment(const char* name,
1803                                        const char* version,
1804                                        Defined defined,
1805                                        Output_segment* os,
1806                                        uint64_t value,
1807                                        uint64_t symsize,
1808                                        elfcpp::STT type,
1809                                        elfcpp::STB binding,
1810                                        elfcpp::STV visibility,
1811                                        unsigned char nonvis,
1812                                        Symbol::Segment_offset_base offset_base,
1813                                        bool only_if_ref)
1814 {
1815   if (parameters->target().get_size() == 32)
1816     {
1817 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1818       return this->do_define_in_output_segment<32>(name, version, defined, os,
1819                                                    value, symsize, type,
1820                                                    binding, visibility, nonvis,
1821                                                    offset_base, only_if_ref);
1822 #else
1823       gold_unreachable();
1824 #endif
1825     }
1826   else if (parameters->target().get_size() == 64)
1827     {
1828 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1829       return this->do_define_in_output_segment<64>(name, version, defined, os,
1830                                                    value, symsize, type,
1831                                                    binding, visibility, nonvis,
1832                                                    offset_base, only_if_ref);
1833 #else
1834       gold_unreachable();
1835 #endif
1836     }
1837   else
1838     gold_unreachable();
1839 }
1840
1841 // Define a symbol in an Output_segment, sized version.
1842
1843 template<int size>
1844 Sized_symbol<size>*
1845 Symbol_table::do_define_in_output_segment(
1846     const char* name,
1847     const char* version,
1848     Defined defined,
1849     Output_segment* os,
1850     typename elfcpp::Elf_types<size>::Elf_Addr value,
1851     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1852     elfcpp::STT type,
1853     elfcpp::STB binding,
1854     elfcpp::STV visibility,
1855     unsigned char nonvis,
1856     Symbol::Segment_offset_base offset_base,
1857     bool only_if_ref)
1858 {
1859   Sized_symbol<size>* sym;
1860   Sized_symbol<size>* oldsym;
1861   bool resolve_oldsym;
1862
1863   if (parameters->target().is_big_endian())
1864     {
1865 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1866       sym = this->define_special_symbol<size, true>(&name, &version,
1867                                                     only_if_ref, &oldsym,
1868                                                     &resolve_oldsym);
1869 #else
1870       gold_unreachable();
1871 #endif
1872     }
1873   else
1874     {
1875 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1876       sym = this->define_special_symbol<size, false>(&name, &version,
1877                                                      only_if_ref, &oldsym,
1878                                                      &resolve_oldsym);
1879 #else
1880       gold_unreachable();
1881 #endif
1882     }
1883
1884   if (sym == NULL)
1885     return NULL;
1886
1887   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1888                            visibility, nonvis, offset_base);
1889
1890   if (oldsym == NULL)
1891     {
1892       if (binding == elfcpp::STB_LOCAL
1893           || this->version_script_.symbol_is_local(name))
1894         this->force_local(sym);
1895       else if (version != NULL)
1896         sym->set_is_default();
1897       return sym;
1898     }
1899
1900   if (Symbol_table::should_override_with_special(oldsym, defined))
1901     this->override_with_special(oldsym, sym);
1902
1903   if (resolve_oldsym)
1904     return sym;
1905   else
1906     {
1907       delete sym;
1908       return oldsym;
1909     }
1910 }
1911
1912 // Define a special symbol with a constant value.  It is a multiple
1913 // definition error if this symbol is already defined.
1914
1915 Symbol*
1916 Symbol_table::define_as_constant(const char* name,
1917                                  const char* version,
1918                                  Defined defined,
1919                                  uint64_t value,
1920                                  uint64_t symsize,
1921                                  elfcpp::STT type,
1922                                  elfcpp::STB binding,
1923                                  elfcpp::STV visibility,
1924                                  unsigned char nonvis,
1925                                  bool only_if_ref,
1926                                  bool force_override)
1927 {
1928   if (parameters->target().get_size() == 32)
1929     {
1930 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1931       return this->do_define_as_constant<32>(name, version, defined, value,
1932                                              symsize, type, binding,
1933                                              visibility, nonvis, only_if_ref,
1934                                              force_override);
1935 #else
1936       gold_unreachable();
1937 #endif
1938     }
1939   else if (parameters->target().get_size() == 64)
1940     {
1941 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1942       return this->do_define_as_constant<64>(name, version, defined, value,
1943                                              symsize, type, binding,
1944                                              visibility, nonvis, only_if_ref,
1945                                              force_override);
1946 #else
1947       gold_unreachable();
1948 #endif
1949     }
1950   else
1951     gold_unreachable();
1952 }
1953
1954 // Define a symbol as a constant, sized version.
1955
1956 template<int size>
1957 Sized_symbol<size>*
1958 Symbol_table::do_define_as_constant(
1959     const char* name,
1960     const char* version,
1961     Defined defined,
1962     typename elfcpp::Elf_types<size>::Elf_Addr value,
1963     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1964     elfcpp::STT type,
1965     elfcpp::STB binding,
1966     elfcpp::STV visibility,
1967     unsigned char nonvis,
1968     bool only_if_ref,
1969     bool force_override)
1970 {
1971   Sized_symbol<size>* sym;
1972   Sized_symbol<size>* oldsym;
1973   bool resolve_oldsym;
1974
1975   if (parameters->target().is_big_endian())
1976     {
1977 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1978       sym = this->define_special_symbol<size, true>(&name, &version,
1979                                                     only_if_ref, &oldsym,
1980                                                     &resolve_oldsym);
1981 #else
1982       gold_unreachable();
1983 #endif
1984     }
1985   else
1986     {
1987 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1988       sym = this->define_special_symbol<size, false>(&name, &version,
1989                                                      only_if_ref, &oldsym,
1990                                                      &resolve_oldsym);
1991 #else
1992       gold_unreachable();
1993 #endif
1994     }
1995
1996   if (sym == NULL)
1997     return NULL;
1998
1999   sym->init_constant(name, version, value, symsize, type, binding, visibility,
2000                      nonvis);
2001
2002   if (oldsym == NULL)
2003     {
2004       // Version symbols are absolute symbols with name == version.
2005       // We don't want to force them to be local.
2006       if ((version == NULL
2007            || name != version
2008            || value != 0)
2009           && (binding == elfcpp::STB_LOCAL
2010               || this->version_script_.symbol_is_local(name)))
2011         this->force_local(sym);
2012       else if (version != NULL
2013                && (name != version || value != 0))
2014         sym->set_is_default();
2015       return sym;
2016     }
2017
2018   if (force_override
2019       || Symbol_table::should_override_with_special(oldsym, defined))
2020     this->override_with_special(oldsym, sym);
2021
2022   if (resolve_oldsym)
2023     return sym;
2024   else
2025     {
2026       delete sym;
2027       return oldsym;
2028     }
2029 }
2030
2031 // Define a set of symbols in output sections.
2032
2033 void
2034 Symbol_table::define_symbols(const Layout* layout, int count,
2035                              const Define_symbol_in_section* p,
2036                              bool only_if_ref)
2037 {
2038   for (int i = 0; i < count; ++i, ++p)
2039     {
2040       Output_section* os = layout->find_output_section(p->output_section);
2041       if (os != NULL)
2042         this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2043                                     p->size, p->type, p->binding,
2044                                     p->visibility, p->nonvis,
2045                                     p->offset_is_from_end,
2046                                     only_if_ref || p->only_if_ref);
2047       else
2048         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2049                                  p->type, p->binding, p->visibility, p->nonvis,
2050                                  only_if_ref || p->only_if_ref,
2051                                  false);
2052     }
2053 }
2054
2055 // Define a set of symbols in output segments.
2056
2057 void
2058 Symbol_table::define_symbols(const Layout* layout, int count,
2059                              const Define_symbol_in_segment* p,
2060                              bool only_if_ref)
2061 {
2062   for (int i = 0; i < count; ++i, ++p)
2063     {
2064       Output_segment* os = layout->find_output_segment(p->segment_type,
2065                                                        p->segment_flags_set,
2066                                                        p->segment_flags_clear);
2067       if (os != NULL)
2068         this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2069                                        p->size, p->type, p->binding,
2070                                        p->visibility, p->nonvis,
2071                                        p->offset_base,
2072                                        only_if_ref || p->only_if_ref);
2073       else
2074         this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2075                                  p->type, p->binding, p->visibility, p->nonvis,
2076                                  only_if_ref || p->only_if_ref,
2077                                  false);
2078     }
2079 }
2080
2081 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2082 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2083 // the offset within POSD.
2084
2085 template<int size>
2086 void
2087 Symbol_table::define_with_copy_reloc(
2088     Sized_symbol<size>* csym,
2089     Output_data* posd,
2090     typename elfcpp::Elf_types<size>::Elf_Addr value)
2091 {
2092   gold_assert(csym->is_from_dynobj());
2093   gold_assert(!csym->is_copied_from_dynobj());
2094   Object* object = csym->object();
2095   gold_assert(object->is_dynamic());
2096   Dynobj* dynobj = static_cast<Dynobj*>(object);
2097
2098   // Our copied variable has to override any variable in a shared
2099   // library.
2100   elfcpp::STB binding = csym->binding();
2101   if (binding == elfcpp::STB_WEAK)
2102     binding = elfcpp::STB_GLOBAL;
2103
2104   this->define_in_output_data(csym->name(), csym->version(), COPY,
2105                               posd, value, csym->symsize(),
2106                               csym->type(), binding,
2107                               csym->visibility(), csym->nonvis(),
2108                               false, false);
2109
2110   csym->set_is_copied_from_dynobj();
2111   csym->set_needs_dynsym_entry();
2112
2113   this->copied_symbol_dynobjs_[csym] = dynobj;
2114
2115   // We have now defined all aliases, but we have not entered them all
2116   // in the copied_symbol_dynobjs_ map.
2117   if (csym->has_alias())
2118     {
2119       Symbol* sym = csym;
2120       while (true)
2121         {
2122           sym = this->weak_aliases_[sym];
2123           if (sym == csym)
2124             break;
2125           gold_assert(sym->output_data() == posd);
2126
2127           sym->set_is_copied_from_dynobj();
2128           this->copied_symbol_dynobjs_[sym] = dynobj;
2129         }
2130     }
2131 }
2132
2133 // SYM is defined using a COPY reloc.  Return the dynamic object where
2134 // the original definition was found.
2135
2136 Dynobj*
2137 Symbol_table::get_copy_source(const Symbol* sym) const
2138 {
2139   gold_assert(sym->is_copied_from_dynobj());
2140   Copied_symbol_dynobjs::const_iterator p =
2141     this->copied_symbol_dynobjs_.find(sym);
2142   gold_assert(p != this->copied_symbol_dynobjs_.end());
2143   return p->second;
2144 }
2145
2146 // Add any undefined symbols named on the command line.
2147
2148 void
2149 Symbol_table::add_undefined_symbols_from_command_line()
2150 {
2151   if (parameters->options().any_undefined())
2152     {
2153       if (parameters->target().get_size() == 32)
2154         {
2155 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2156           this->do_add_undefined_symbols_from_command_line<32>();
2157 #else
2158           gold_unreachable();
2159 #endif
2160         }
2161       else if (parameters->target().get_size() == 64)
2162         {
2163 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2164           this->do_add_undefined_symbols_from_command_line<64>();
2165 #else
2166           gold_unreachable();
2167 #endif
2168         }
2169       else
2170         gold_unreachable();
2171     }
2172 }
2173
2174 template<int size>
2175 void
2176 Symbol_table::do_add_undefined_symbols_from_command_line()
2177 {
2178   for (options::String_set::const_iterator p =
2179          parameters->options().undefined_begin();
2180        p != parameters->options().undefined_end();
2181        ++p)
2182     {
2183       const char* name = p->c_str();
2184
2185       if (this->lookup(name) != NULL)
2186         continue;
2187
2188       const char* version = NULL;
2189
2190       Sized_symbol<size>* sym;
2191       Sized_symbol<size>* oldsym;
2192       bool resolve_oldsym;
2193       if (parameters->target().is_big_endian())
2194         {
2195 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2196           sym = this->define_special_symbol<size, true>(&name, &version,
2197                                                         false, &oldsym,
2198                                                         &resolve_oldsym);
2199 #else
2200           gold_unreachable();
2201 #endif
2202         }
2203       else
2204         {
2205 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2206           sym = this->define_special_symbol<size, false>(&name, &version,
2207                                                          false, &oldsym,
2208                                                          &resolve_oldsym);
2209 #else
2210           gold_unreachable();
2211 #endif
2212         }
2213
2214       gold_assert(oldsym == NULL);
2215
2216       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2217                           elfcpp::STV_DEFAULT, 0);
2218       ++this->saw_undefined_;
2219     }
2220 }
2221
2222 // Set the dynamic symbol indexes.  INDEX is the index of the first
2223 // global dynamic symbol.  Pointers to the symbols are stored into the
2224 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2225 // updated dynamic symbol index.
2226
2227 unsigned int
2228 Symbol_table::set_dynsym_indexes(unsigned int index,
2229                                  std::vector<Symbol*>* syms,
2230                                  Stringpool* dynpool,
2231                                  Versions* versions)
2232 {
2233   for (Symbol_table_type::iterator p = this->table_.begin();
2234        p != this->table_.end();
2235        ++p)
2236     {
2237       Symbol* sym = p->second;
2238
2239       // Note that SYM may already have a dynamic symbol index, since
2240       // some symbols appear more than once in the symbol table, with
2241       // and without a version.
2242
2243       if (!sym->should_add_dynsym_entry())
2244         sym->set_dynsym_index(-1U);
2245       else if (!sym->has_dynsym_index())
2246         {
2247           sym->set_dynsym_index(index);
2248           ++index;
2249           syms->push_back(sym);
2250           dynpool->add(sym->name(), false, NULL);
2251
2252           // Record any version information.
2253           if (sym->version() != NULL)
2254             versions->record_version(this, dynpool, sym);
2255
2256           // If the symbol is defined in a dynamic object and is
2257           // referenced in a regular object, then mark the dynamic
2258           // object as needed.  This is used to implement --as-needed.
2259           if (sym->is_from_dynobj() && sym->in_reg())
2260             sym->object()->set_is_needed();
2261         }
2262     }
2263
2264   // Finish up the versions.  In some cases this may add new dynamic
2265   // symbols.
2266   index = versions->finalize(this, index, syms);
2267
2268   return index;
2269 }
2270
2271 // Set the final values for all the symbols.  The index of the first
2272 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2273 // file offset OFF.  Add their names to POOL.  Return the new file
2274 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2275
2276 off_t
2277 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2278                        size_t dyncount, Stringpool* pool,
2279                        unsigned int *plocal_symcount)
2280 {
2281   off_t ret;
2282
2283   gold_assert(*plocal_symcount != 0);
2284   this->first_global_index_ = *plocal_symcount;
2285
2286   this->dynamic_offset_ = dynoff;
2287   this->first_dynamic_global_index_ = dyn_global_index;
2288   this->dynamic_count_ = dyncount;
2289
2290   if (parameters->target().get_size() == 32)
2291     {
2292 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2293       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2294 #else
2295       gold_unreachable();
2296 #endif
2297     }
2298   else if (parameters->target().get_size() == 64)
2299     {
2300 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2301       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2302 #else
2303       gold_unreachable();
2304 #endif
2305     }
2306   else
2307     gold_unreachable();
2308
2309   // Now that we have the final symbol table, we can reliably note
2310   // which symbols should get warnings.
2311   this->warnings_.note_warnings(this);
2312
2313   return ret;
2314 }
2315
2316 // SYM is going into the symbol table at *PINDEX.  Add the name to
2317 // POOL, update *PINDEX and *POFF.
2318
2319 template<int size>
2320 void
2321 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2322                                   unsigned int* pindex, off_t* poff)
2323 {
2324   sym->set_symtab_index(*pindex);
2325   pool->add(sym->name(), false, NULL);
2326   ++*pindex;
2327   *poff += elfcpp::Elf_sizes<size>::sym_size;
2328 }
2329
2330 // Set the final value for all the symbols.  This is called after
2331 // Layout::finalize, so all the output sections have their final
2332 // address.
2333
2334 template<int size>
2335 off_t
2336 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2337                              unsigned int* plocal_symcount)
2338 {
2339   off = align_address(off, size >> 3);
2340   this->offset_ = off;
2341
2342   unsigned int index = *plocal_symcount;
2343   const unsigned int orig_index = index;
2344
2345   // First do all the symbols which have been forced to be local, as
2346   // they must appear before all global symbols.
2347   for (Forced_locals::iterator p = this->forced_locals_.begin();
2348        p != this->forced_locals_.end();
2349        ++p)
2350     {
2351       Symbol* sym = *p;
2352       gold_assert(sym->is_forced_local());
2353       if (this->sized_finalize_symbol<size>(sym))
2354         {
2355           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2356           ++*plocal_symcount;
2357         }
2358     }
2359
2360   // Now do all the remaining symbols.
2361   for (Symbol_table_type::iterator p = this->table_.begin();
2362        p != this->table_.end();
2363        ++p)
2364     {
2365       Symbol* sym = p->second;
2366       if (this->sized_finalize_symbol<size>(sym))
2367         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2368     }
2369
2370   this->output_count_ = index - orig_index;
2371
2372   return off;
2373 }
2374
2375 // Compute the final value of SYM and store status in location PSTATUS.
2376 // During relaxation, this may be called multiple times for a symbol to
2377 // compute its would-be final value in each relaxation pass.
2378
2379 template<int size>
2380 typename Sized_symbol<size>::Value_type
2381 Symbol_table::compute_final_value(
2382     const Sized_symbol<size>* sym,
2383     Compute_final_value_status* pstatus) const
2384 {
2385   typedef typename Sized_symbol<size>::Value_type Value_type;
2386   Value_type value;
2387
2388   switch (sym->source())
2389     {
2390     case Symbol::FROM_OBJECT:
2391       {
2392         bool is_ordinary;
2393         unsigned int shndx = sym->shndx(&is_ordinary);
2394
2395         if (!is_ordinary
2396             && shndx != elfcpp::SHN_ABS
2397             && !Symbol::is_common_shndx(shndx))
2398           {
2399             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2400             return 0;
2401           }
2402
2403         Object* symobj = sym->object();
2404         if (symobj->is_dynamic())
2405           {
2406             value = 0;
2407             shndx = elfcpp::SHN_UNDEF;
2408           }
2409         else if (symobj->pluginobj() != NULL)
2410           {
2411             value = 0;
2412             shndx = elfcpp::SHN_UNDEF;
2413           }
2414         else if (shndx == elfcpp::SHN_UNDEF)
2415           value = 0;
2416         else if (!is_ordinary
2417                  && (shndx == elfcpp::SHN_ABS
2418                      || Symbol::is_common_shndx(shndx)))
2419           value = sym->value();
2420         else
2421           {
2422             Relobj* relobj = static_cast<Relobj*>(symobj);
2423             Output_section* os = relobj->output_section(shndx);
2424
2425             if (this->is_section_folded(relobj, shndx))
2426               {
2427                 gold_assert(os == NULL);
2428                 // Get the os of the section it is folded onto.
2429                 Section_id folded = this->icf_->get_folded_section(relobj,
2430                                                                    shndx);
2431                 gold_assert(folded.first != NULL);
2432                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2433                 unsigned folded_shndx = folded.second;
2434
2435                 os = folded_obj->output_section(folded_shndx);  
2436                 gold_assert(os != NULL);
2437
2438                 // Replace (relobj, shndx) with canonical ICF input section.
2439                 shndx = folded_shndx;
2440                 relobj = folded_obj;
2441               }
2442
2443             uint64_t secoff64 = relobj->output_section_offset(shndx);
2444             if (os == NULL)
2445               {
2446                 bool static_or_reloc = (parameters->doing_static_link() ||
2447                                         parameters->options().relocatable());
2448                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2449
2450                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2451                 return 0;
2452               }
2453
2454             if (secoff64 == -1ULL)
2455               {
2456                 // The section needs special handling (e.g., a merge section).
2457
2458                 value = os->output_address(relobj, shndx, sym->value());
2459               }
2460             else
2461               {
2462                 Value_type secoff =
2463                   convert_types<Value_type, uint64_t>(secoff64);
2464                 if (sym->type() == elfcpp::STT_TLS)
2465                   value = sym->value() + os->tls_offset() + secoff;
2466                 else
2467                   value = sym->value() + os->address() + secoff;
2468               }
2469           }
2470       }
2471       break;
2472
2473     case Symbol::IN_OUTPUT_DATA:
2474       {
2475         Output_data* od = sym->output_data();
2476         value = sym->value();
2477         if (sym->type() != elfcpp::STT_TLS)
2478           value += od->address();
2479         else
2480           {
2481             Output_section* os = od->output_section();
2482             gold_assert(os != NULL);
2483             value += os->tls_offset() + (od->address() - os->address());
2484           }
2485         if (sym->offset_is_from_end())
2486           value += od->data_size();
2487       }
2488       break;
2489
2490     case Symbol::IN_OUTPUT_SEGMENT:
2491       {
2492         Output_segment* os = sym->output_segment();
2493         value = sym->value();
2494         if (sym->type() != elfcpp::STT_TLS)
2495           value += os->vaddr();
2496         switch (sym->offset_base())
2497           {
2498           case Symbol::SEGMENT_START:
2499             break;
2500           case Symbol::SEGMENT_END:
2501             value += os->memsz();
2502             break;
2503           case Symbol::SEGMENT_BSS:
2504             value += os->filesz();
2505             break;
2506           default:
2507             gold_unreachable();
2508           }
2509       }
2510       break;
2511
2512     case Symbol::IS_CONSTANT:
2513       value = sym->value();
2514       break;
2515
2516     case Symbol::IS_UNDEFINED:
2517       value = 0;
2518       break;
2519
2520     default:
2521       gold_unreachable();
2522     }
2523
2524   *pstatus = CFVS_OK;
2525   return value;
2526 }
2527
2528 // Finalize the symbol SYM.  This returns true if the symbol should be
2529 // added to the symbol table, false otherwise.
2530
2531 template<int size>
2532 bool
2533 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2534 {
2535   typedef typename Sized_symbol<size>::Value_type Value_type;
2536
2537   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2538
2539   // The default version of a symbol may appear twice in the symbol
2540   // table.  We only need to finalize it once.
2541   if (sym->has_symtab_index())
2542     return false;
2543
2544   if (!sym->in_reg())
2545     {
2546       gold_assert(!sym->has_symtab_index());
2547       sym->set_symtab_index(-1U);
2548       gold_assert(sym->dynsym_index() == -1U);
2549       return false;
2550     }
2551
2552   // Compute final symbol value.
2553   Compute_final_value_status status;
2554   Value_type value = this->compute_final_value(sym, &status);
2555
2556   switch (status)
2557     {
2558     case CFVS_OK:
2559       break;
2560     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2561       {
2562         bool is_ordinary;
2563         unsigned int shndx = sym->shndx(&is_ordinary);
2564         gold_error(_("%s: unsupported symbol section 0x%x"),
2565                    sym->demangled_name().c_str(), shndx);
2566       }
2567       break;
2568     case CFVS_NO_OUTPUT_SECTION:
2569       sym->set_symtab_index(-1U);
2570       return false;
2571     default:
2572       gold_unreachable();
2573     }
2574
2575   sym->set_value(value);
2576
2577   if (parameters->options().strip_all()
2578       || !parameters->options().should_retain_symbol(sym->name()))
2579     {
2580       sym->set_symtab_index(-1U);
2581       return false;
2582     }
2583
2584   return true;
2585 }
2586
2587 // Write out the global symbols.
2588
2589 void
2590 Symbol_table::write_globals(const Stringpool* sympool,
2591                             const Stringpool* dynpool,
2592                             Output_symtab_xindex* symtab_xindex,
2593                             Output_symtab_xindex* dynsym_xindex,
2594                             Output_file* of) const
2595 {
2596   switch (parameters->size_and_endianness())
2597     {
2598 #ifdef HAVE_TARGET_32_LITTLE
2599     case Parameters::TARGET_32_LITTLE:
2600       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2601                                            dynsym_xindex, of);
2602       break;
2603 #endif
2604 #ifdef HAVE_TARGET_32_BIG
2605     case Parameters::TARGET_32_BIG:
2606       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2607                                           dynsym_xindex, of);
2608       break;
2609 #endif
2610 #ifdef HAVE_TARGET_64_LITTLE
2611     case Parameters::TARGET_64_LITTLE:
2612       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2613                                            dynsym_xindex, of);
2614       break;
2615 #endif
2616 #ifdef HAVE_TARGET_64_BIG
2617     case Parameters::TARGET_64_BIG:
2618       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2619                                           dynsym_xindex, of);
2620       break;
2621 #endif
2622     default:
2623       gold_unreachable();
2624     }
2625 }
2626
2627 // Write out the global symbols.
2628
2629 template<int size, bool big_endian>
2630 void
2631 Symbol_table::sized_write_globals(const Stringpool* sympool,
2632                                   const Stringpool* dynpool,
2633                                   Output_symtab_xindex* symtab_xindex,
2634                                   Output_symtab_xindex* dynsym_xindex,
2635                                   Output_file* of) const
2636 {
2637   const Target& target = parameters->target();
2638
2639   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2640
2641   const unsigned int output_count = this->output_count_;
2642   const section_size_type oview_size = output_count * sym_size;
2643   const unsigned int first_global_index = this->first_global_index_;
2644   unsigned char* psyms;
2645   if (this->offset_ == 0 || output_count == 0)
2646     psyms = NULL;
2647   else
2648     psyms = of->get_output_view(this->offset_, oview_size);
2649
2650   const unsigned int dynamic_count = this->dynamic_count_;
2651   const section_size_type dynamic_size = dynamic_count * sym_size;
2652   const unsigned int first_dynamic_global_index =
2653     this->first_dynamic_global_index_;
2654   unsigned char* dynamic_view;
2655   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2656     dynamic_view = NULL;
2657   else
2658     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2659
2660   for (Symbol_table_type::const_iterator p = this->table_.begin();
2661        p != this->table_.end();
2662        ++p)
2663     {
2664       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2665
2666       // Possibly warn about unresolved symbols in shared libraries.
2667       this->warn_about_undefined_dynobj_symbol(sym);
2668
2669       unsigned int sym_index = sym->symtab_index();
2670       unsigned int dynsym_index;
2671       if (dynamic_view == NULL)
2672         dynsym_index = -1U;
2673       else
2674         dynsym_index = sym->dynsym_index();
2675
2676       if (sym_index == -1U && dynsym_index == -1U)
2677         {
2678           // This symbol is not included in the output file.
2679           continue;
2680         }
2681
2682       unsigned int shndx;
2683       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2684       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2685       switch (sym->source())
2686         {
2687         case Symbol::FROM_OBJECT:
2688           {
2689             bool is_ordinary;
2690             unsigned int in_shndx = sym->shndx(&is_ordinary);
2691
2692             if (!is_ordinary
2693                 && in_shndx != elfcpp::SHN_ABS
2694                 && !Symbol::is_common_shndx(in_shndx))
2695               {
2696                 gold_error(_("%s: unsupported symbol section 0x%x"),
2697                            sym->demangled_name().c_str(), in_shndx);
2698                 shndx = in_shndx;
2699               }
2700             else
2701               {
2702                 Object* symobj = sym->object();
2703                 if (symobj->is_dynamic())
2704                   {
2705                     if (sym->needs_dynsym_value())
2706                       dynsym_value = target.dynsym_value(sym);
2707                     shndx = elfcpp::SHN_UNDEF;
2708                   }
2709                 else if (symobj->pluginobj() != NULL)
2710                   shndx = elfcpp::SHN_UNDEF;
2711                 else if (in_shndx == elfcpp::SHN_UNDEF
2712                          || (!is_ordinary
2713                              && (in_shndx == elfcpp::SHN_ABS
2714                                  || Symbol::is_common_shndx(in_shndx))))
2715                   shndx = in_shndx;
2716                 else
2717                   {
2718                     Relobj* relobj = static_cast<Relobj*>(symobj);
2719                     Output_section* os = relobj->output_section(in_shndx);
2720                     if (this->is_section_folded(relobj, in_shndx))
2721                       {
2722                         // This global symbol must be written out even though
2723                         // it is folded.
2724                         // Get the os of the section it is folded onto.
2725                         Section_id folded =
2726                              this->icf_->get_folded_section(relobj, in_shndx);
2727                         gold_assert(folded.first !=NULL);
2728                         Relobj* folded_obj = 
2729                           reinterpret_cast<Relobj*>(folded.first);
2730                         os = folded_obj->output_section(folded.second);  
2731                         gold_assert(os != NULL);
2732                       }
2733                     gold_assert(os != NULL);
2734                     shndx = os->out_shndx();
2735
2736                     if (shndx >= elfcpp::SHN_LORESERVE)
2737                       {
2738                         if (sym_index != -1U)
2739                           symtab_xindex->add(sym_index, shndx);
2740                         if (dynsym_index != -1U)
2741                           dynsym_xindex->add(dynsym_index, shndx);
2742                         shndx = elfcpp::SHN_XINDEX;
2743                       }
2744
2745                     // In object files symbol values are section
2746                     // relative.
2747                     if (parameters->options().relocatable())
2748                       sym_value -= os->address();
2749                   }
2750               }
2751           }
2752           break;
2753
2754         case Symbol::IN_OUTPUT_DATA:
2755           shndx = sym->output_data()->out_shndx();
2756           if (shndx >= elfcpp::SHN_LORESERVE)
2757             {
2758               if (sym_index != -1U)
2759                 symtab_xindex->add(sym_index, shndx);
2760               if (dynsym_index != -1U)
2761                 dynsym_xindex->add(dynsym_index, shndx);
2762               shndx = elfcpp::SHN_XINDEX;
2763             }
2764           break;
2765
2766         case Symbol::IN_OUTPUT_SEGMENT:
2767           shndx = elfcpp::SHN_ABS;
2768           break;
2769
2770         case Symbol::IS_CONSTANT:
2771           shndx = elfcpp::SHN_ABS;
2772           break;
2773
2774         case Symbol::IS_UNDEFINED:
2775           shndx = elfcpp::SHN_UNDEF;
2776           break;
2777
2778         default:
2779           gold_unreachable();
2780         }
2781
2782       if (sym_index != -1U)
2783         {
2784           sym_index -= first_global_index;
2785           gold_assert(sym_index < output_count);
2786           unsigned char* ps = psyms + (sym_index * sym_size);
2787           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2788                                                      sympool, ps);
2789         }
2790
2791       if (dynsym_index != -1U)
2792         {
2793           dynsym_index -= first_dynamic_global_index;
2794           gold_assert(dynsym_index < dynamic_count);
2795           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2796           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2797                                                      dynpool, pd);
2798         }
2799     }
2800
2801   of->write_output_view(this->offset_, oview_size, psyms);
2802   if (dynamic_view != NULL)
2803     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2804 }
2805
2806 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2807 // strtab holding the name.
2808
2809 template<int size, bool big_endian>
2810 void
2811 Symbol_table::sized_write_symbol(
2812     Sized_symbol<size>* sym,
2813     typename elfcpp::Elf_types<size>::Elf_Addr value,
2814     unsigned int shndx,
2815     const Stringpool* pool,
2816     unsigned char* p) const
2817 {
2818   elfcpp::Sym_write<size, big_endian> osym(p);
2819   osym.put_st_name(pool->get_offset(sym->name()));
2820   osym.put_st_value(value);
2821   // Use a symbol size of zero for undefined symbols from shared libraries.
2822   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2823     osym.put_st_size(0);
2824   else
2825     osym.put_st_size(sym->symsize());
2826   elfcpp::STT type = sym->type();
2827   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2828   if (type == elfcpp::STT_GNU_IFUNC
2829       && sym->is_from_dynobj())
2830     type = elfcpp::STT_FUNC;
2831   // A version script may have overridden the default binding.
2832   if (sym->is_forced_local())
2833     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2834   else
2835     osym.put_st_info(elfcpp::elf_st_info(sym->binding(), type));
2836   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2837   osym.put_st_shndx(shndx);
2838 }
2839
2840 // Check for unresolved symbols in shared libraries.  This is
2841 // controlled by the --allow-shlib-undefined option.
2842
2843 // We only warn about libraries for which we have seen all the
2844 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2845 // which were not seen in this link.  If we didn't see a DT_NEEDED
2846 // entry, we aren't going to be able to reliably report whether the
2847 // symbol is undefined.
2848
2849 // We also don't warn about libraries found in a system library
2850 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2851 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2852 // can have undefined references satisfied by ld-linux.so.
2853
2854 inline void
2855 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2856 {
2857   bool dummy;
2858   if (sym->source() == Symbol::FROM_OBJECT
2859       && sym->object()->is_dynamic()
2860       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2861       && sym->binding() != elfcpp::STB_WEAK
2862       && !parameters->options().allow_shlib_undefined()
2863       && !parameters->target().is_defined_by_abi(sym)
2864       && !sym->object()->is_in_system_directory())
2865     {
2866       // A very ugly cast.
2867       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2868       if (!dynobj->has_unknown_needed_entries())
2869         gold_undefined_symbol(sym);
2870     }
2871 }
2872
2873 // Write out a section symbol.  Return the update offset.
2874
2875 void
2876 Symbol_table::write_section_symbol(const Output_section *os,
2877                                    Output_symtab_xindex* symtab_xindex,
2878                                    Output_file* of,
2879                                    off_t offset) const
2880 {
2881   switch (parameters->size_and_endianness())
2882     {
2883 #ifdef HAVE_TARGET_32_LITTLE
2884     case Parameters::TARGET_32_LITTLE:
2885       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2886                                                   offset);
2887       break;
2888 #endif
2889 #ifdef HAVE_TARGET_32_BIG
2890     case Parameters::TARGET_32_BIG:
2891       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2892                                                  offset);
2893       break;
2894 #endif
2895 #ifdef HAVE_TARGET_64_LITTLE
2896     case Parameters::TARGET_64_LITTLE:
2897       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2898                                                   offset);
2899       break;
2900 #endif
2901 #ifdef HAVE_TARGET_64_BIG
2902     case Parameters::TARGET_64_BIG:
2903       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2904                                                  offset);
2905       break;
2906 #endif
2907     default:
2908       gold_unreachable();
2909     }
2910 }
2911
2912 // Write out a section symbol, specialized for size and endianness.
2913
2914 template<int size, bool big_endian>
2915 void
2916 Symbol_table::sized_write_section_symbol(const Output_section* os,
2917                                          Output_symtab_xindex* symtab_xindex,
2918                                          Output_file* of,
2919                                          off_t offset) const
2920 {
2921   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2922
2923   unsigned char* pov = of->get_output_view(offset, sym_size);
2924
2925   elfcpp::Sym_write<size, big_endian> osym(pov);
2926   osym.put_st_name(0);
2927   if (parameters->options().relocatable())
2928     osym.put_st_value(0);
2929   else
2930     osym.put_st_value(os->address());
2931   osym.put_st_size(0);
2932   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2933                                        elfcpp::STT_SECTION));
2934   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2935
2936   unsigned int shndx = os->out_shndx();
2937   if (shndx >= elfcpp::SHN_LORESERVE)
2938     {
2939       symtab_xindex->add(os->symtab_index(), shndx);
2940       shndx = elfcpp::SHN_XINDEX;
2941     }
2942   osym.put_st_shndx(shndx);
2943
2944   of->write_output_view(offset, sym_size, pov);
2945 }
2946
2947 // Print statistical information to stderr.  This is used for --stats.
2948
2949 void
2950 Symbol_table::print_stats() const
2951 {
2952 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2953   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2954           program_name, this->table_.size(), this->table_.bucket_count());
2955 #else
2956   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2957           program_name, this->table_.size());
2958 #endif
2959   this->namepool_.print_stats("symbol table stringpool");
2960 }
2961
2962 // We check for ODR violations by looking for symbols with the same
2963 // name for which the debugging information reports that they were
2964 // defined in different source locations.  When comparing the source
2965 // location, we consider instances with the same base filename and
2966 // line number to be the same.  This is because different object
2967 // files/shared libraries can include the same header file using
2968 // different paths, and we don't want to report an ODR violation in
2969 // that case.
2970
2971 // This struct is used to compare line information, as returned by
2972 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2973 // operator used with std::set.
2974
2975 struct Odr_violation_compare
2976 {
2977   bool
2978   operator()(const std::string& s1, const std::string& s2) const
2979   {
2980     std::string::size_type pos1 = s1.rfind('/');
2981     std::string::size_type pos2 = s2.rfind('/');
2982     if (pos1 == std::string::npos
2983         || pos2 == std::string::npos)
2984       return s1 < s2;
2985     return s1.compare(pos1, std::string::npos,
2986                       s2, pos2, std::string::npos) < 0;
2987   }
2988 };
2989
2990 // Check candidate_odr_violations_ to find symbols with the same name
2991 // but apparently different definitions (different source-file/line-no).
2992
2993 void
2994 Symbol_table::detect_odr_violations(const Task* task,
2995                                     const char* output_file_name) const
2996 {
2997   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2998        it != candidate_odr_violations_.end();
2999        ++it)
3000     {
3001       const char* symbol_name = it->first;
3002       // We use a sorted set so the output is deterministic.
3003       std::set<std::string, Odr_violation_compare> line_nums;
3004
3005       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3006                locs = it->second.begin();
3007            locs != it->second.end();
3008            ++locs)
3009         {
3010           // We need to lock the object in order to read it.  This
3011           // means that we have to run in a singleton Task.  If we
3012           // want to run this in a general Task for better
3013           // performance, we will need one Task for object, plus
3014           // appropriate locking to ensure that we don't conflict with
3015           // other uses of the object.  Also note, one_addr2line is not
3016           // currently thread-safe.
3017           Task_lock_obj<Object> tl(task, locs->object);
3018           // 16 is the size of the object-cache that one_addr2line should use.
3019           std::string lineno = Dwarf_line_info::one_addr2line(
3020               locs->object, locs->shndx, locs->offset, 16);
3021           if (!lineno.empty())
3022             line_nums.insert(lineno);
3023         }
3024
3025       if (line_nums.size() > 1)
3026         {
3027           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3028                          "places (possible ODR violation):"),
3029                        output_file_name, demangle(symbol_name).c_str());
3030           for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3031                it2 != line_nums.end();
3032                ++it2)
3033             fprintf(stderr, "  %s\n", it2->c_str());
3034         }
3035     }
3036   // We only call one_addr2line() in this function, so we can clear its cache.
3037   Dwarf_line_info::clear_addr2line_cache();
3038 }
3039
3040 // Warnings functions.
3041
3042 // Add a new warning.
3043
3044 void
3045 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3046                       const std::string& warning)
3047 {
3048   name = symtab->canonicalize_name(name);
3049   this->warnings_[name].set(obj, warning);
3050 }
3051
3052 // Look through the warnings and mark the symbols for which we should
3053 // warn.  This is called during Layout::finalize when we know the
3054 // sources for all the symbols.
3055
3056 void
3057 Warnings::note_warnings(Symbol_table* symtab)
3058 {
3059   for (Warning_table::iterator p = this->warnings_.begin();
3060        p != this->warnings_.end();
3061        ++p)
3062     {
3063       Symbol* sym = symtab->lookup(p->first, NULL);
3064       if (sym != NULL
3065           && sym->source() == Symbol::FROM_OBJECT
3066           && sym->object() == p->second.object)
3067         sym->set_has_warning();
3068     }
3069 }
3070
3071 // Issue a warning.  This is called when we see a relocation against a
3072 // symbol for which has a warning.
3073
3074 template<int size, bool big_endian>
3075 void
3076 Warnings::issue_warning(const Symbol* sym,
3077                         const Relocate_info<size, big_endian>* relinfo,
3078                         size_t relnum, off_t reloffset) const
3079 {
3080   gold_assert(sym->has_warning());
3081   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3082   gold_assert(p != this->warnings_.end());
3083   gold_warning_at_location(relinfo, relnum, reloffset,
3084                            "%s", p->second.text.c_str());
3085 }
3086
3087 // Instantiate the templates we need.  We could use the configure
3088 // script to restrict this to only the ones needed for implemented
3089 // targets.
3090
3091 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3092 template
3093 void
3094 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3095 #endif
3096
3097 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3098 template
3099 void
3100 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3101 #endif
3102
3103 #ifdef HAVE_TARGET_32_LITTLE
3104 template
3105 void
3106 Symbol_table::add_from_relobj<32, false>(
3107     Sized_relobj<32, false>* relobj,
3108     const unsigned char* syms,
3109     size_t count,
3110     size_t symndx_offset,
3111     const char* sym_names,
3112     size_t sym_name_size,
3113     Sized_relobj<32, false>::Symbols* sympointers,
3114     size_t* defined);
3115 #endif
3116
3117 #ifdef HAVE_TARGET_32_BIG
3118 template
3119 void
3120 Symbol_table::add_from_relobj<32, true>(
3121     Sized_relobj<32, true>* relobj,
3122     const unsigned char* syms,
3123     size_t count,
3124     size_t symndx_offset,
3125     const char* sym_names,
3126     size_t sym_name_size,
3127     Sized_relobj<32, true>::Symbols* sympointers,
3128     size_t* defined);
3129 #endif
3130
3131 #ifdef HAVE_TARGET_64_LITTLE
3132 template
3133 void
3134 Symbol_table::add_from_relobj<64, false>(
3135     Sized_relobj<64, false>* relobj,
3136     const unsigned char* syms,
3137     size_t count,
3138     size_t symndx_offset,
3139     const char* sym_names,
3140     size_t sym_name_size,
3141     Sized_relobj<64, false>::Symbols* sympointers,
3142     size_t* defined);
3143 #endif
3144
3145 #ifdef HAVE_TARGET_64_BIG
3146 template
3147 void
3148 Symbol_table::add_from_relobj<64, true>(
3149     Sized_relobj<64, true>* relobj,
3150     const unsigned char* syms,
3151     size_t count,
3152     size_t symndx_offset,
3153     const char* sym_names,
3154     size_t sym_name_size,
3155     Sized_relobj<64, true>::Symbols* sympointers,
3156     size_t* defined);
3157 #endif
3158
3159 #ifdef HAVE_TARGET_32_LITTLE
3160 template
3161 Symbol*
3162 Symbol_table::add_from_pluginobj<32, false>(
3163     Sized_pluginobj<32, false>* obj,
3164     const char* name,
3165     const char* ver,
3166     elfcpp::Sym<32, false>* sym);
3167 #endif
3168
3169 #ifdef HAVE_TARGET_32_BIG
3170 template
3171 Symbol*
3172 Symbol_table::add_from_pluginobj<32, true>(
3173     Sized_pluginobj<32, true>* obj,
3174     const char* name,
3175     const char* ver,
3176     elfcpp::Sym<32, true>* sym);
3177 #endif
3178
3179 #ifdef HAVE_TARGET_64_LITTLE
3180 template
3181 Symbol*
3182 Symbol_table::add_from_pluginobj<64, false>(
3183     Sized_pluginobj<64, false>* obj,
3184     const char* name,
3185     const char* ver,
3186     elfcpp::Sym<64, false>* sym);
3187 #endif
3188
3189 #ifdef HAVE_TARGET_64_BIG
3190 template
3191 Symbol*
3192 Symbol_table::add_from_pluginobj<64, true>(
3193     Sized_pluginobj<64, true>* obj,
3194     const char* name,
3195     const char* ver,
3196     elfcpp::Sym<64, true>* sym);
3197 #endif
3198
3199 #ifdef HAVE_TARGET_32_LITTLE
3200 template
3201 void
3202 Symbol_table::add_from_dynobj<32, false>(
3203     Sized_dynobj<32, false>* dynobj,
3204     const unsigned char* syms,
3205     size_t count,
3206     const char* sym_names,
3207     size_t sym_name_size,
3208     const unsigned char* versym,
3209     size_t versym_size,
3210     const std::vector<const char*>* version_map,
3211     Sized_relobj<32, false>::Symbols* sympointers,
3212     size_t* defined);
3213 #endif
3214
3215 #ifdef HAVE_TARGET_32_BIG
3216 template
3217 void
3218 Symbol_table::add_from_dynobj<32, true>(
3219     Sized_dynobj<32, true>* dynobj,
3220     const unsigned char* syms,
3221     size_t count,
3222     const char* sym_names,
3223     size_t sym_name_size,
3224     const unsigned char* versym,
3225     size_t versym_size,
3226     const std::vector<const char*>* version_map,
3227     Sized_relobj<32, true>::Symbols* sympointers,
3228     size_t* defined);
3229 #endif
3230
3231 #ifdef HAVE_TARGET_64_LITTLE
3232 template
3233 void
3234 Symbol_table::add_from_dynobj<64, false>(
3235     Sized_dynobj<64, false>* dynobj,
3236     const unsigned char* syms,
3237     size_t count,
3238     const char* sym_names,
3239     size_t sym_name_size,
3240     const unsigned char* versym,
3241     size_t versym_size,
3242     const std::vector<const char*>* version_map,
3243     Sized_relobj<64, false>::Symbols* sympointers,
3244     size_t* defined);
3245 #endif
3246
3247 #ifdef HAVE_TARGET_64_BIG
3248 template
3249 void
3250 Symbol_table::add_from_dynobj<64, true>(
3251     Sized_dynobj<64, true>* dynobj,
3252     const unsigned char* syms,
3253     size_t count,
3254     const char* sym_names,
3255     size_t sym_name_size,
3256     const unsigned char* versym,
3257     size_t versym_size,
3258     const std::vector<const char*>* version_map,
3259     Sized_relobj<64, true>::Symbols* sympointers,
3260     size_t* defined);
3261 #endif
3262
3263 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3264 template
3265 void
3266 Symbol_table::define_with_copy_reloc<32>(
3267     Sized_symbol<32>* sym,
3268     Output_data* posd,
3269     elfcpp::Elf_types<32>::Elf_Addr value);
3270 #endif
3271
3272 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3273 template
3274 void
3275 Symbol_table::define_with_copy_reloc<64>(
3276     Sized_symbol<64>* sym,
3277     Output_data* posd,
3278     elfcpp::Elf_types<64>::Elf_Addr value);
3279 #endif
3280
3281 #ifdef HAVE_TARGET_32_LITTLE
3282 template
3283 void
3284 Warnings::issue_warning<32, false>(const Symbol* sym,
3285                                    const Relocate_info<32, false>* relinfo,
3286                                    size_t relnum, off_t reloffset) const;
3287 #endif
3288
3289 #ifdef HAVE_TARGET_32_BIG
3290 template
3291 void
3292 Warnings::issue_warning<32, true>(const Symbol* sym,
3293                                   const Relocate_info<32, true>* relinfo,
3294                                   size_t relnum, off_t reloffset) const;
3295 #endif
3296
3297 #ifdef HAVE_TARGET_64_LITTLE
3298 template
3299 void
3300 Warnings::issue_warning<64, false>(const Symbol* sym,
3301                                    const Relocate_info<64, false>* relinfo,
3302                                    size_t relnum, off_t reloffset) const;
3303 #endif
3304
3305 #ifdef HAVE_TARGET_64_BIG
3306 template
3307 void
3308 Warnings::issue_warning<64, true>(const Symbol* sym,
3309                                   const Relocate_info<64, true>* relinfo,
3310                                   size_t relnum, off_t reloffset) const;
3311 #endif
3312
3313 } // End namespace gold.
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