Import binutils-2.20
[dragonfly.git] / contrib / binutils-2.20 / gold / symtab.cc
1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
32
33 #include "gc.h"
34 #include "object.h"
35 #include "dwarf_reader.h"
36 #include "dynobj.h"
37 #include "output.h"
38 #include "target.h"
39 #include "workqueue.h"
40 #include "symtab.h"
41 #include "demangle.h"   // needed for --dynamic-list-cpp-new
42 #include "plugin.h"
43
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol.  This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54                     elfcpp::STT type, elfcpp::STB binding,
55                     elfcpp::STV visibility, unsigned char nonvis)
56 {
57   this->name_ = name;
58   this->version_ = version;
59   this->symtab_index_ = 0;
60   this->dynsym_index_ = 0;
61   this->got_offsets_.init();
62   this->plt_offset_ = 0;
63   this->type_ = type;
64   this->binding_ = binding;
65   this->visibility_ = visibility;
66   this->nonvis_ = nonvis;
67   this->is_target_special_ = false;
68   this->is_def_ = false;
69   this->is_forwarder_ = false;
70   this->has_alias_ = false;
71   this->needs_dynsym_entry_ = false;
72   this->in_reg_ = false;
73   this->in_dyn_ = false;
74   this->has_plt_offset_ = false;
75   this->has_warning_ = false;
76   this->is_copied_from_dynobj_ = false;
77   this->is_forced_local_ = false;
78   this->is_ordinary_shndx_ = false;
79   this->in_real_elf_ = false;
80 }
81
82 // Return the demangled version of the symbol's name, but only
83 // if the --demangle flag was set.
84
85 static std::string
86 demangle(const char* name)
87 {
88   if (!parameters->options().do_demangle())
89     return name;
90
91   // cplus_demangle allocates memory for the result it returns,
92   // and returns NULL if the name is already demangled.
93   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
94   if (demangled_name == NULL)
95     return name;
96
97   std::string retval(demangled_name);
98   free(demangled_name);
99   return retval;
100 }
101
102 std::string
103 Symbol::demangled_name() const
104 {
105   return demangle(this->name());
106 }
107
108 // Initialize the fields in the base class Symbol for SYM in OBJECT.
109
110 template<int size, bool big_endian>
111 void
112 Symbol::init_base_object(const char* name, const char* version, Object* object,
113                          const elfcpp::Sym<size, big_endian>& sym,
114                          unsigned int st_shndx, bool is_ordinary)
115 {
116   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
117                     sym.get_st_visibility(), sym.get_st_nonvis());
118   this->u_.from_object.object = object;
119   this->u_.from_object.shndx = st_shndx;
120   this->is_ordinary_shndx_ = is_ordinary;
121   this->source_ = FROM_OBJECT;
122   this->in_reg_ = !object->is_dynamic();
123   this->in_dyn_ = object->is_dynamic();
124   this->in_real_elf_ = object->pluginobj() == NULL;
125 }
126
127 // Initialize the fields in the base class Symbol for a symbol defined
128 // in an Output_data.
129
130 void
131 Symbol::init_base_output_data(const char* name, const char* version,
132                               Output_data* od, elfcpp::STT type,
133                               elfcpp::STB binding, elfcpp::STV visibility,
134                               unsigned char nonvis, bool offset_is_from_end)
135 {
136   this->init_fields(name, version, type, binding, visibility, nonvis);
137   this->u_.in_output_data.output_data = od;
138   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
139   this->source_ = IN_OUTPUT_DATA;
140   this->in_reg_ = true;
141   this->in_real_elf_ = true;
142 }
143
144 // Initialize the fields in the base class Symbol for a symbol defined
145 // in an Output_segment.
146
147 void
148 Symbol::init_base_output_segment(const char* name, const char* version,
149                                  Output_segment* os, elfcpp::STT type,
150                                  elfcpp::STB binding, elfcpp::STV visibility,
151                                  unsigned char nonvis,
152                                  Segment_offset_base offset_base)
153 {
154   this->init_fields(name, version, type, binding, visibility, nonvis);
155   this->u_.in_output_segment.output_segment = os;
156   this->u_.in_output_segment.offset_base = offset_base;
157   this->source_ = IN_OUTPUT_SEGMENT;
158   this->in_reg_ = true;
159   this->in_real_elf_ = true;
160 }
161
162 // Initialize the fields in the base class Symbol for a symbol defined
163 // as a constant.
164
165 void
166 Symbol::init_base_constant(const char* name, const char* version,
167                            elfcpp::STT type, elfcpp::STB binding,
168                            elfcpp::STV visibility, unsigned char nonvis)
169 {
170   this->init_fields(name, version, type, binding, visibility, nonvis);
171   this->source_ = IS_CONSTANT;
172   this->in_reg_ = true;
173   this->in_real_elf_ = true;
174 }
175
176 // Initialize the fields in the base class Symbol for an undefined
177 // symbol.
178
179 void
180 Symbol::init_base_undefined(const char* name, const char* version,
181                             elfcpp::STT type, elfcpp::STB binding,
182                             elfcpp::STV visibility, unsigned char nonvis)
183 {
184   this->init_fields(name, version, type, binding, visibility, nonvis);
185   this->dynsym_index_ = -1U;
186   this->source_ = IS_UNDEFINED;
187   this->in_reg_ = true;
188   this->in_real_elf_ = true;
189 }
190
191 // Allocate a common symbol in the base.
192
193 void
194 Symbol::allocate_base_common(Output_data* od)
195 {
196   gold_assert(this->is_common());
197   this->source_ = IN_OUTPUT_DATA;
198   this->u_.in_output_data.output_data = od;
199   this->u_.in_output_data.offset_is_from_end = false;
200 }
201
202 // Initialize the fields in Sized_symbol for SYM in OBJECT.
203
204 template<int size>
205 template<bool big_endian>
206 void
207 Sized_symbol<size>::init_object(const char* name, const char* version,
208                                 Object* object,
209                                 const elfcpp::Sym<size, big_endian>& sym,
210                                 unsigned int st_shndx, bool is_ordinary)
211 {
212   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
213   this->value_ = sym.get_st_value();
214   this->symsize_ = sym.get_st_size();
215 }
216
217 // Initialize the fields in Sized_symbol for a symbol defined in an
218 // Output_data.
219
220 template<int size>
221 void
222 Sized_symbol<size>::init_output_data(const char* name, const char* version,
223                                      Output_data* od, Value_type value,
224                                      Size_type symsize, elfcpp::STT type,
225                                      elfcpp::STB binding,
226                                      elfcpp::STV visibility,
227                                      unsigned char nonvis,
228                                      bool offset_is_from_end)
229 {
230   this->init_base_output_data(name, version, od, type, binding, visibility,
231                               nonvis, offset_is_from_end);
232   this->value_ = value;
233   this->symsize_ = symsize;
234 }
235
236 // Initialize the fields in Sized_symbol for a symbol defined in an
237 // Output_segment.
238
239 template<int size>
240 void
241 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
242                                         Output_segment* os, Value_type value,
243                                         Size_type symsize, elfcpp::STT type,
244                                         elfcpp::STB binding,
245                                         elfcpp::STV visibility,
246                                         unsigned char nonvis,
247                                         Segment_offset_base offset_base)
248 {
249   this->init_base_output_segment(name, version, os, type, binding, visibility,
250                                  nonvis, offset_base);
251   this->value_ = value;
252   this->symsize_ = symsize;
253 }
254
255 // Initialize the fields in Sized_symbol for a symbol defined as a
256 // constant.
257
258 template<int size>
259 void
260 Sized_symbol<size>::init_constant(const char* name, const char* version,
261                                   Value_type value, Size_type symsize,
262                                   elfcpp::STT type, elfcpp::STB binding,
263                                   elfcpp::STV visibility, unsigned char nonvis)
264 {
265   this->init_base_constant(name, version, type, binding, visibility, nonvis);
266   this->value_ = value;
267   this->symsize_ = symsize;
268 }
269
270 // Initialize the fields in Sized_symbol for an undefined symbol.
271
272 template<int size>
273 void
274 Sized_symbol<size>::init_undefined(const char* name, const char* version,
275                                    elfcpp::STT type, elfcpp::STB binding,
276                                    elfcpp::STV visibility, unsigned char nonvis)
277 {
278   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
279   this->value_ = 0;
280   this->symsize_ = 0;
281 }
282
283 // Return true if SHNDX represents a common symbol.
284
285 bool
286 Symbol::is_common_shndx(unsigned int shndx)
287 {
288   return (shndx == elfcpp::SHN_COMMON
289           || shndx == parameters->target().small_common_shndx()
290           || shndx == parameters->target().large_common_shndx());
291 }
292
293 // Allocate a common symbol.
294
295 template<int size>
296 void
297 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
298 {
299   this->allocate_base_common(od);
300   this->value_ = value;
301 }
302
303 // The ""'s around str ensure str is a string literal, so sizeof works.
304 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
305
306 // Return true if this symbol should be added to the dynamic symbol
307 // table.
308
309 inline bool
310 Symbol::should_add_dynsym_entry() const
311 {
312   // If the symbol is used by a dynamic relocation, we need to add it.
313   if (this->needs_dynsym_entry())
314     return true;
315
316   // If this symbol's section is not added, the symbol need not be added. 
317   // The section may have been GCed.  Note that export_dynamic is being 
318   // overridden here.  This should not be done for shared objects.
319   if (parameters->options().gc_sections() 
320       && !parameters->options().shared()
321       && this->source() == Symbol::FROM_OBJECT
322       && !this->object()->is_dynamic())
323     {
324       Relobj* relobj = static_cast<Relobj*>(this->object());
325       bool is_ordinary;
326       unsigned int shndx = this->shndx(&is_ordinary);
327       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
328           && !relobj->is_section_included(shndx))
329         return false;
330     }
331
332   // If the symbol was forced local in a version script, do not add it.
333   if (this->is_forced_local())
334     return false;
335
336   // If the symbol was forced dynamic in a --dynamic-list file, add it.
337   if (parameters->options().in_dynamic_list(this->name()))
338     return true;
339
340   // If dynamic-list-data was specified, add any STT_OBJECT.
341   if (parameters->options().dynamic_list_data()
342       && !this->is_from_dynobj()
343       && this->type() == elfcpp::STT_OBJECT)
344     return true;
345
346   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
347   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
348   if ((parameters->options().dynamic_list_cpp_new()
349        || parameters->options().dynamic_list_cpp_typeinfo())
350       && !this->is_from_dynobj())
351     {
352       // TODO(csilvers): We could probably figure out if we're an operator
353       //                 new/delete or typeinfo without the need to demangle.
354       char* demangled_name = cplus_demangle(this->name(),
355                                             DMGL_ANSI | DMGL_PARAMS);
356       if (demangled_name == NULL)
357         {
358           // Not a C++ symbol, so it can't satisfy these flags
359         }
360       else if (parameters->options().dynamic_list_cpp_new()
361                && (strprefix(demangled_name, "operator new")
362                    || strprefix(demangled_name, "operator delete")))
363         {
364           free(demangled_name);
365           return true;
366         }
367       else if (parameters->options().dynamic_list_cpp_typeinfo()
368                && (strprefix(demangled_name, "typeinfo name for")
369                    || strprefix(demangled_name, "typeinfo for")))
370         {
371           free(demangled_name);
372           return true;
373         }
374       else
375         free(demangled_name);
376     }
377
378   // If exporting all symbols or building a shared library,
379   // and the symbol is defined in a regular object and is
380   // externally visible, we need to add it.
381   if ((parameters->options().export_dynamic() || parameters->options().shared())
382       && !this->is_from_dynobj()
383       && this->is_externally_visible())
384     return true;
385
386   return false;
387 }
388
389 // Return true if the final value of this symbol is known at link
390 // time.
391
392 bool
393 Symbol::final_value_is_known() const
394 {
395   // If we are not generating an executable, then no final values are
396   // known, since they will change at runtime.
397   if (parameters->options().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_WEAK)
1014       && !parameters->options().relocatable())
1015     this->force_local(ret);
1016
1017   return ret;
1018 }
1019
1020 // Add all the symbols in a relocatable object to the hash table.
1021
1022 template<int size, bool big_endian>
1023 void
1024 Symbol_table::add_from_relobj(
1025     Sized_relobj<size, big_endian>* relobj,
1026     const unsigned char* syms,
1027     size_t count,
1028     size_t symndx_offset,
1029     const char* sym_names,
1030     size_t sym_name_size,
1031     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1032     size_t *defined)
1033 {
1034   *defined = 0;
1035
1036   gold_assert(size == parameters->target().get_size());
1037
1038   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1039
1040   const bool just_symbols = relobj->just_symbols();
1041
1042   const unsigned char* p = syms;
1043   for (size_t i = 0; i < count; ++i, p += sym_size)
1044     {
1045       (*sympointers)[i] = NULL;
1046
1047       elfcpp::Sym<size, big_endian> sym(p);
1048
1049       unsigned int st_name = sym.get_st_name();
1050       if (st_name >= sym_name_size)
1051         {
1052           relobj->error(_("bad global symbol name offset %u at %zu"),
1053                         st_name, i);
1054           continue;
1055         }
1056
1057       const char* name = sym_names + st_name;
1058
1059       bool is_ordinary;
1060       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1061                                                        sym.get_st_shndx(),
1062                                                        &is_ordinary);
1063       unsigned int orig_st_shndx = st_shndx;
1064       if (!is_ordinary)
1065         orig_st_shndx = elfcpp::SHN_UNDEF;
1066
1067       if (st_shndx != elfcpp::SHN_UNDEF)
1068         ++*defined;
1069
1070       // A symbol defined in a section which we are not including must
1071       // be treated as an undefined symbol.
1072       if (st_shndx != elfcpp::SHN_UNDEF
1073           && is_ordinary
1074           && !relobj->is_section_included(st_shndx))
1075         st_shndx = elfcpp::SHN_UNDEF;
1076
1077       // In an object file, an '@' in the name separates the symbol
1078       // name from the version name.  If there are two '@' characters,
1079       // this is the default version.
1080       const char* ver = strchr(name, '@');
1081       Stringpool::Key ver_key = 0;
1082       int namelen = 0;
1083       // DEF: is the version default?  LOCAL: is the symbol forced local?
1084       bool def = false;
1085       bool local = false;
1086
1087       if (ver != NULL)
1088         {
1089           // The symbol name is of the form foo@VERSION or foo@@VERSION
1090           namelen = ver - name;
1091           ++ver;
1092           if (*ver == '@')
1093             {
1094               def = true;
1095               ++ver;
1096             }
1097           ver = this->namepool_.add(ver, true, &ver_key);
1098         }
1099       // We don't want to assign a version to an undefined symbol,
1100       // even if it is listed in the version script.  FIXME: What
1101       // about a common symbol?
1102       else
1103         {
1104           namelen = strlen(name);
1105           if (!this->version_script_.empty()
1106               && st_shndx != elfcpp::SHN_UNDEF)
1107             {
1108               // The symbol name did not have a version, but the
1109               // version script may assign a version anyway.
1110               std::string version;
1111               if (this->version_script_.get_symbol_version(name, &version))
1112                 {
1113                   // The version can be empty if the version script is
1114                   // only used to force some symbols to be local.
1115                   if (!version.empty())
1116                     {
1117                       ver = this->namepool_.add_with_length(version.c_str(),
1118                                                             version.length(),
1119                                                             true,
1120                                                             &ver_key);
1121                       def = true;
1122                     }
1123                 }
1124               else if (this->version_script_.symbol_is_local(name))
1125                 local = true;
1126             }
1127         }
1128
1129       elfcpp::Sym<size, big_endian>* psym = &sym;
1130       unsigned char symbuf[sym_size];
1131       elfcpp::Sym<size, big_endian> sym2(symbuf);
1132       if (just_symbols)
1133         {
1134           memcpy(symbuf, p, sym_size);
1135           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1136           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1137             {
1138               // Symbol values in object files are section relative.
1139               // This is normally what we want, but since here we are
1140               // converting the symbol to absolute we need to add the
1141               // section address.  The section address in an object
1142               // file is normally zero, but people can use a linker
1143               // script to change it.
1144               sw.put_st_value(sym.get_st_value()
1145                               + relobj->section_address(orig_st_shndx));
1146             }
1147           st_shndx = elfcpp::SHN_ABS;
1148           is_ordinary = false;
1149           psym = &sym2;
1150         }
1151
1152       // Fix up visibility if object has no-export set.
1153       if (relobj->no_export())
1154         {
1155           // We may have copied symbol already above.
1156           if (psym != &sym2)
1157             {
1158               memcpy(symbuf, p, sym_size);
1159               psym = &sym2;
1160             }
1161
1162           elfcpp::STV visibility = sym2.get_st_visibility();
1163           if (visibility == elfcpp::STV_DEFAULT
1164               || visibility == elfcpp::STV_PROTECTED)
1165             {
1166               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1167               unsigned char nonvis = sym2.get_st_nonvis();
1168               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1169             }
1170         }
1171
1172       Stringpool::Key name_key;
1173       name = this->namepool_.add_with_length(name, namelen, true,
1174                                              &name_key);
1175
1176       Sized_symbol<size>* res;
1177       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1178                                   def, *psym, st_shndx, is_ordinary,
1179                                   orig_st_shndx);
1180       
1181       // If building a shared library using garbage collection, do not 
1182       // treat externally visible symbols as garbage.
1183       if (parameters->options().gc_sections() 
1184           && parameters->options().shared())
1185         this->gc_mark_symbol_for_shlib(res);
1186
1187       if (local)
1188         this->force_local(res);
1189
1190       (*sympointers)[i] = res;
1191     }
1192 }
1193
1194 // Add a symbol from a plugin-claimed file.
1195
1196 template<int size, bool big_endian>
1197 Symbol*
1198 Symbol_table::add_from_pluginobj(
1199     Sized_pluginobj<size, big_endian>* obj,
1200     const char* name,
1201     const char* ver,
1202     elfcpp::Sym<size, big_endian>* sym)
1203 {
1204   unsigned int st_shndx = sym->get_st_shndx();
1205
1206   Stringpool::Key ver_key = 0;
1207   bool def = false;
1208   bool local = false;
1209
1210   if (ver != NULL)
1211     {
1212       ver = this->namepool_.add(ver, true, &ver_key);
1213     }
1214   // We don't want to assign a version to an undefined symbol,
1215   // even if it is listed in the version script.  FIXME: What
1216   // about a common symbol?
1217   else
1218     {
1219       if (!this->version_script_.empty()
1220           && st_shndx != elfcpp::SHN_UNDEF)
1221         {
1222           // The symbol name did not have a version, but the
1223           // version script may assign a version anyway.
1224           std::string version;
1225           if (this->version_script_.get_symbol_version(name, &version))
1226             {
1227               // The version can be empty if the version script is
1228               // only used to force some symbols to be local.
1229               if (!version.empty())
1230                 {
1231                   ver = this->namepool_.add_with_length(version.c_str(),
1232                                                         version.length(),
1233                                                         true,
1234                                                         &ver_key);
1235                   def = true;
1236                 }
1237             }
1238           else if (this->version_script_.symbol_is_local(name))
1239             local = true;
1240         }
1241     }
1242
1243   Stringpool::Key name_key;
1244   name = this->namepool_.add(name, true, &name_key);
1245
1246   Sized_symbol<size>* res;
1247   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1248                               def, *sym, st_shndx, true, st_shndx);
1249
1250   if (local)
1251     this->force_local(res);
1252
1253   return res;
1254 }
1255
1256 // Add all the symbols in a dynamic object to the hash table.
1257
1258 template<int size, bool big_endian>
1259 void
1260 Symbol_table::add_from_dynobj(
1261     Sized_dynobj<size, big_endian>* dynobj,
1262     const unsigned char* syms,
1263     size_t count,
1264     const char* sym_names,
1265     size_t sym_name_size,
1266     const unsigned char* versym,
1267     size_t versym_size,
1268     const std::vector<const char*>* version_map,
1269     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1270     size_t* defined)
1271 {
1272   *defined = 0;
1273
1274   gold_assert(size == parameters->target().get_size());
1275
1276   if (dynobj->just_symbols())
1277     {
1278       gold_error(_("--just-symbols does not make sense with a shared object"));
1279       return;
1280     }
1281
1282   if (versym != NULL && versym_size / 2 < count)
1283     {
1284       dynobj->error(_("too few symbol versions"));
1285       return;
1286     }
1287
1288   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1289
1290   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1291   // weak aliases.  This is necessary because if the dynamic object
1292   // provides the same variable under two names, one of which is a
1293   // weak definition, and the regular object refers to the weak
1294   // definition, we have to put both the weak definition and the
1295   // strong definition into the dynamic symbol table.  Given a weak
1296   // definition, the only way that we can find the corresponding
1297   // strong definition, if any, is to search the symbol table.
1298   std::vector<Sized_symbol<size>*> object_symbols;
1299
1300   const unsigned char* p = syms;
1301   const unsigned char* vs = versym;
1302   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1303     {
1304       elfcpp::Sym<size, big_endian> sym(p);
1305
1306       if (sympointers != NULL)
1307         (*sympointers)[i] = NULL;
1308
1309       // Ignore symbols with local binding or that have
1310       // internal or hidden visibility.
1311       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1312           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1313           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1314         continue;
1315
1316       // A protected symbol in a shared library must be treated as a
1317       // normal symbol when viewed from outside the shared library.
1318       // Implement this by overriding the visibility here.
1319       elfcpp::Sym<size, big_endian>* psym = &sym;
1320       unsigned char symbuf[sym_size];
1321       elfcpp::Sym<size, big_endian> sym2(symbuf);
1322       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1323         {
1324           memcpy(symbuf, p, sym_size);
1325           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1326           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1327           psym = &sym2;
1328         }
1329
1330       unsigned int st_name = psym->get_st_name();
1331       if (st_name >= sym_name_size)
1332         {
1333           dynobj->error(_("bad symbol name offset %u at %zu"),
1334                         st_name, i);
1335           continue;
1336         }
1337
1338       const char* name = sym_names + st_name;
1339
1340       bool is_ordinary;
1341       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1342                                                        &is_ordinary);
1343
1344       if (st_shndx != elfcpp::SHN_UNDEF)
1345         ++*defined;
1346
1347       Sized_symbol<size>* res;
1348
1349       if (versym == NULL)
1350         {
1351           Stringpool::Key name_key;
1352           name = this->namepool_.add(name, true, &name_key);
1353           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1354                                       false, *psym, st_shndx, is_ordinary,
1355                                       st_shndx);
1356         }
1357       else
1358         {
1359           // Read the version information.
1360
1361           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1362
1363           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1364           v &= elfcpp::VERSYM_VERSION;
1365
1366           // The Sun documentation says that V can be VER_NDX_LOCAL,
1367           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1368           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1369           // The old GNU linker will happily generate VER_NDX_LOCAL
1370           // for an undefined symbol.  I don't know what the Sun
1371           // linker will generate.
1372
1373           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1374               && st_shndx != elfcpp::SHN_UNDEF)
1375             {
1376               // This symbol should not be visible outside the object.
1377               continue;
1378             }
1379
1380           // At this point we are definitely going to add this symbol.
1381           Stringpool::Key name_key;
1382           name = this->namepool_.add(name, true, &name_key);
1383
1384           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1385               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1386             {
1387               // This symbol does not have a version.
1388               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1389                                           false, *psym, st_shndx, is_ordinary,
1390                                           st_shndx);
1391             }
1392           else
1393             {
1394               if (v >= version_map->size())
1395                 {
1396                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1397                                 i, v);
1398                   continue;
1399                 }
1400
1401               const char* version = (*version_map)[v];
1402               if (version == NULL)
1403                 {
1404                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1405                                 i, v);
1406                   continue;
1407                 }
1408
1409               Stringpool::Key version_key;
1410               version = this->namepool_.add(version, true, &version_key);
1411
1412               // If this is an absolute symbol, and the version name
1413               // and symbol name are the same, then this is the
1414               // version definition symbol.  These symbols exist to
1415               // support using -u to pull in particular versions.  We
1416               // do not want to record a version for them.
1417               if (st_shndx == elfcpp::SHN_ABS
1418                   && !is_ordinary
1419                   && name_key == version_key)
1420                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1421                                             false, *psym, st_shndx, is_ordinary,
1422                                             st_shndx);
1423               else
1424                 {
1425                   const bool def = (!hidden
1426                                     && st_shndx != elfcpp::SHN_UNDEF);
1427                   res = this->add_from_object(dynobj, name, name_key, version,
1428                                               version_key, def, *psym, st_shndx,
1429                                               is_ordinary, st_shndx);
1430                 }
1431             }
1432         }
1433
1434       // Note that it is possible that RES was overridden by an
1435       // earlier object, in which case it can't be aliased here.
1436       if (st_shndx != elfcpp::SHN_UNDEF
1437           && is_ordinary
1438           && psym->get_st_type() == elfcpp::STT_OBJECT
1439           && res->source() == Symbol::FROM_OBJECT
1440           && res->object() == dynobj)
1441         object_symbols.push_back(res);
1442
1443       if (sympointers != NULL)
1444         (*sympointers)[i] = res;
1445     }
1446
1447   this->record_weak_aliases(&object_symbols);
1448 }
1449
1450 // This is used to sort weak aliases.  We sort them first by section
1451 // index, then by offset, then by weak ahead of strong.
1452
1453 template<int size>
1454 class Weak_alias_sorter
1455 {
1456  public:
1457   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1458 };
1459
1460 template<int size>
1461 bool
1462 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1463                                     const Sized_symbol<size>* s2) const
1464 {
1465   bool is_ordinary;
1466   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1467   gold_assert(is_ordinary);
1468   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1469   gold_assert(is_ordinary);
1470   if (s1_shndx != s2_shndx)
1471     return s1_shndx < s2_shndx;
1472
1473   if (s1->value() != s2->value())
1474     return s1->value() < s2->value();
1475   if (s1->binding() != s2->binding())
1476     {
1477       if (s1->binding() == elfcpp::STB_WEAK)
1478         return true;
1479       if (s2->binding() == elfcpp::STB_WEAK)
1480         return false;
1481     }
1482   return std::string(s1->name()) < std::string(s2->name());
1483 }
1484
1485 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1486 // for any weak aliases, and record them so that if we add the weak
1487 // alias to the dynamic symbol table, we also add the corresponding
1488 // strong symbol.
1489
1490 template<int size>
1491 void
1492 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1493 {
1494   // Sort the vector by section index, then by offset, then by weak
1495   // ahead of strong.
1496   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1497
1498   // Walk through the vector.  For each weak definition, record
1499   // aliases.
1500   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1501          symbols->begin();
1502        p != symbols->end();
1503        ++p)
1504     {
1505       if ((*p)->binding() != elfcpp::STB_WEAK)
1506         continue;
1507
1508       // Build a circular list of weak aliases.  Each symbol points to
1509       // the next one in the circular list.
1510
1511       Sized_symbol<size>* from_sym = *p;
1512       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1513       for (q = p + 1; q != symbols->end(); ++q)
1514         {
1515           bool dummy;
1516           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1517               || (*q)->value() != from_sym->value())
1518             break;
1519
1520           this->weak_aliases_[from_sym] = *q;
1521           from_sym->set_has_alias();
1522           from_sym = *q;
1523         }
1524
1525       if (from_sym != *p)
1526         {
1527           this->weak_aliases_[from_sym] = *p;
1528           from_sym->set_has_alias();
1529         }
1530
1531       p = q - 1;
1532     }
1533 }
1534
1535 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1536 // true, then only create the symbol if there is a reference to it.
1537 // If this does not return NULL, it sets *POLDSYM to the existing
1538 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1539 // resolve the newly created symbol to the old one.  This
1540 // canonicalizes *PNAME and *PVERSION.
1541
1542 template<int size, bool big_endian>
1543 Sized_symbol<size>*
1544 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1545                                     bool only_if_ref,
1546                                     Sized_symbol<size>** poldsym,
1547                                     bool *resolve_oldsym)
1548 {
1549   *resolve_oldsym = false;
1550
1551   // If the caller didn't give us a version, see if we get one from
1552   // the version script.
1553   std::string v;
1554   bool is_default_version = false;
1555   if (*pversion == NULL)
1556     {
1557       if (this->version_script_.get_symbol_version(*pname, &v))
1558         {
1559           if (!v.empty())
1560             *pversion = v.c_str();
1561
1562           // If we get the version from a version script, then we are
1563           // also the default version.
1564           is_default_version = true;
1565         }
1566     }
1567
1568   Symbol* oldsym;
1569   Sized_symbol<size>* sym;
1570
1571   bool add_to_table = false;
1572   typename Symbol_table_type::iterator add_loc = this->table_.end();
1573   bool add_def_to_table = false;
1574   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1575
1576   if (only_if_ref)
1577     {
1578       oldsym = this->lookup(*pname, *pversion);
1579       if (oldsym == NULL && is_default_version)
1580         oldsym = this->lookup(*pname, NULL);
1581       if (oldsym == NULL || !oldsym->is_undefined())
1582         return NULL;
1583
1584       *pname = oldsym->name();
1585       if (!is_default_version)
1586         *pversion = oldsym->version();
1587     }
1588   else
1589     {
1590       // Canonicalize NAME and VERSION.
1591       Stringpool::Key name_key;
1592       *pname = this->namepool_.add(*pname, true, &name_key);
1593
1594       Stringpool::Key version_key = 0;
1595       if (*pversion != NULL)
1596         *pversion = this->namepool_.add(*pversion, true, &version_key);
1597
1598       Symbol* const snull = NULL;
1599       std::pair<typename Symbol_table_type::iterator, bool> ins =
1600         this->table_.insert(std::make_pair(std::make_pair(name_key,
1601                                                           version_key),
1602                                            snull));
1603
1604       std::pair<typename Symbol_table_type::iterator, bool> insdef =
1605         std::make_pair(this->table_.end(), false);
1606       if (is_default_version)
1607         {
1608           const Stringpool::Key vnull = 0;
1609           insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
1610                                                                      vnull),
1611                                                       snull));
1612         }
1613
1614       if (!ins.second)
1615         {
1616           // We already have a symbol table entry for NAME/VERSION.
1617           oldsym = ins.first->second;
1618           gold_assert(oldsym != NULL);
1619
1620           if (is_default_version)
1621             {
1622               Sized_symbol<size>* soldsym =
1623                 this->get_sized_symbol<size>(oldsym);
1624               this->define_default_version<size, big_endian>(soldsym,
1625                                                              insdef.second,
1626                                                              insdef.first);
1627             }
1628         }
1629       else
1630         {
1631           // We haven't seen this symbol before.
1632           gold_assert(ins.first->second == NULL);
1633
1634           add_to_table = true;
1635           add_loc = ins.first;
1636
1637           if (is_default_version && !insdef.second)
1638             {
1639               // We are adding NAME/VERSION, and it is the default
1640               // version.  We already have an entry for NAME/NULL.
1641               oldsym = insdef.first->second;
1642               *resolve_oldsym = true;
1643             }
1644           else
1645             {
1646               oldsym = NULL;
1647
1648               if (is_default_version)
1649                 {
1650                   add_def_to_table = true;
1651                   add_def_loc = insdef.first;
1652                 }
1653             }
1654         }
1655     }
1656
1657   const Target& target = parameters->target();
1658   if (!target.has_make_symbol())
1659     sym = new Sized_symbol<size>();
1660   else
1661     {
1662       Sized_target<size, big_endian>* sized_target =
1663         parameters->sized_target<size, big_endian>();
1664       sym = sized_target->make_symbol();
1665       if (sym == NULL)
1666         return NULL;
1667     }
1668
1669   if (add_to_table)
1670     add_loc->second = sym;
1671   else
1672     gold_assert(oldsym != NULL);
1673
1674   if (add_def_to_table)
1675     add_def_loc->second = sym;
1676
1677   *poldsym = this->get_sized_symbol<size>(oldsym);
1678
1679   return sym;
1680 }
1681
1682 // Define a symbol based on an Output_data.
1683
1684 Symbol*
1685 Symbol_table::define_in_output_data(const char* name,
1686                                     const char* version,
1687                                     Output_data* od,
1688                                     uint64_t value,
1689                                     uint64_t symsize,
1690                                     elfcpp::STT type,
1691                                     elfcpp::STB binding,
1692                                     elfcpp::STV visibility,
1693                                     unsigned char nonvis,
1694                                     bool offset_is_from_end,
1695                                     bool only_if_ref)
1696 {
1697   if (parameters->target().get_size() == 32)
1698     {
1699 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1700       return this->do_define_in_output_data<32>(name, version, od,
1701                                                 value, symsize, type, binding,
1702                                                 visibility, nonvis,
1703                                                 offset_is_from_end,
1704                                                 only_if_ref);
1705 #else
1706       gold_unreachable();
1707 #endif
1708     }
1709   else if (parameters->target().get_size() == 64)
1710     {
1711 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1712       return this->do_define_in_output_data<64>(name, version, od,
1713                                                 value, symsize, type, binding,
1714                                                 visibility, nonvis,
1715                                                 offset_is_from_end,
1716                                                 only_if_ref);
1717 #else
1718       gold_unreachable();
1719 #endif
1720     }
1721   else
1722     gold_unreachable();
1723 }
1724
1725 // Define a symbol in an Output_data, sized version.
1726
1727 template<int size>
1728 Sized_symbol<size>*
1729 Symbol_table::do_define_in_output_data(
1730     const char* name,
1731     const char* version,
1732     Output_data* od,
1733     typename elfcpp::Elf_types<size>::Elf_Addr value,
1734     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1735     elfcpp::STT type,
1736     elfcpp::STB binding,
1737     elfcpp::STV visibility,
1738     unsigned char nonvis,
1739     bool offset_is_from_end,
1740     bool only_if_ref)
1741 {
1742   Sized_symbol<size>* sym;
1743   Sized_symbol<size>* oldsym;
1744   bool resolve_oldsym;
1745
1746   if (parameters->target().is_big_endian())
1747     {
1748 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1749       sym = this->define_special_symbol<size, true>(&name, &version,
1750                                                     only_if_ref, &oldsym,
1751                                                     &resolve_oldsym);
1752 #else
1753       gold_unreachable();
1754 #endif
1755     }
1756   else
1757     {
1758 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1759       sym = this->define_special_symbol<size, false>(&name, &version,
1760                                                      only_if_ref, &oldsym,
1761                                                      &resolve_oldsym);
1762 #else
1763       gold_unreachable();
1764 #endif
1765     }
1766
1767   if (sym == NULL)
1768     return NULL;
1769
1770   sym->init_output_data(name, version, od, value, symsize, type, binding,
1771                         visibility, nonvis, offset_is_from_end);
1772
1773   if (oldsym == NULL)
1774     {
1775       if (binding == elfcpp::STB_LOCAL
1776           || this->version_script_.symbol_is_local(name))
1777         this->force_local(sym);
1778       else if (version != NULL)
1779         sym->set_is_default();
1780       return sym;
1781     }
1782
1783   if (Symbol_table::should_override_with_special(oldsym))
1784     this->override_with_special(oldsym, sym);
1785
1786   if (resolve_oldsym)
1787     return sym;
1788   else
1789     {
1790       delete sym;
1791       return oldsym;
1792     }
1793 }
1794
1795 // Define a symbol based on an Output_segment.
1796
1797 Symbol*
1798 Symbol_table::define_in_output_segment(const char* name,
1799                                        const char* version, Output_segment* os,
1800                                        uint64_t value,
1801                                        uint64_t symsize,
1802                                        elfcpp::STT type,
1803                                        elfcpp::STB binding,
1804                                        elfcpp::STV visibility,
1805                                        unsigned char nonvis,
1806                                        Symbol::Segment_offset_base offset_base,
1807                                        bool only_if_ref)
1808 {
1809   if (parameters->target().get_size() == 32)
1810     {
1811 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1812       return this->do_define_in_output_segment<32>(name, version, os,
1813                                                    value, symsize, type,
1814                                                    binding, visibility, nonvis,
1815                                                    offset_base, only_if_ref);
1816 #else
1817       gold_unreachable();
1818 #endif
1819     }
1820   else if (parameters->target().get_size() == 64)
1821     {
1822 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1823       return this->do_define_in_output_segment<64>(name, version, os,
1824                                                    value, symsize, type,
1825                                                    binding, visibility, nonvis,
1826                                                    offset_base, only_if_ref);
1827 #else
1828       gold_unreachable();
1829 #endif
1830     }
1831   else
1832     gold_unreachable();
1833 }
1834
1835 // Define a symbol in an Output_segment, sized version.
1836
1837 template<int size>
1838 Sized_symbol<size>*
1839 Symbol_table::do_define_in_output_segment(
1840     const char* name,
1841     const char* version,
1842     Output_segment* os,
1843     typename elfcpp::Elf_types<size>::Elf_Addr value,
1844     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1845     elfcpp::STT type,
1846     elfcpp::STB binding,
1847     elfcpp::STV visibility,
1848     unsigned char nonvis,
1849     Symbol::Segment_offset_base offset_base,
1850     bool only_if_ref)
1851 {
1852   Sized_symbol<size>* sym;
1853   Sized_symbol<size>* oldsym;
1854   bool resolve_oldsym;
1855
1856   if (parameters->target().is_big_endian())
1857     {
1858 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1859       sym = this->define_special_symbol<size, true>(&name, &version,
1860                                                     only_if_ref, &oldsym,
1861                                                     &resolve_oldsym);
1862 #else
1863       gold_unreachable();
1864 #endif
1865     }
1866   else
1867     {
1868 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1869       sym = this->define_special_symbol<size, false>(&name, &version,
1870                                                      only_if_ref, &oldsym,
1871                                                      &resolve_oldsym);
1872 #else
1873       gold_unreachable();
1874 #endif
1875     }
1876
1877   if (sym == NULL)
1878     return NULL;
1879
1880   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1881                            visibility, nonvis, offset_base);
1882
1883   if (oldsym == NULL)
1884     {
1885       if (binding == elfcpp::STB_LOCAL
1886           || this->version_script_.symbol_is_local(name))
1887         this->force_local(sym);
1888       else if (version != NULL)
1889         sym->set_is_default();
1890       return sym;
1891     }
1892
1893   if (Symbol_table::should_override_with_special(oldsym))
1894     this->override_with_special(oldsym, sym);
1895
1896   if (resolve_oldsym)
1897     return sym;
1898   else
1899     {
1900       delete sym;
1901       return oldsym;
1902     }
1903 }
1904
1905 // Define a special symbol with a constant value.  It is a multiple
1906 // definition error if this symbol is already defined.
1907
1908 Symbol*
1909 Symbol_table::define_as_constant(const char* name,
1910                                  const char* version,
1911                                  uint64_t value,
1912                                  uint64_t symsize,
1913                                  elfcpp::STT type,
1914                                  elfcpp::STB binding,
1915                                  elfcpp::STV visibility,
1916                                  unsigned char nonvis,
1917                                  bool only_if_ref,
1918                                  bool force_override)
1919 {
1920   if (parameters->target().get_size() == 32)
1921     {
1922 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1923       return this->do_define_as_constant<32>(name, version, value,
1924                                              symsize, type, binding,
1925                                              visibility, nonvis, only_if_ref,
1926                                              force_override);
1927 #else
1928       gold_unreachable();
1929 #endif
1930     }
1931   else if (parameters->target().get_size() == 64)
1932     {
1933 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1934       return this->do_define_as_constant<64>(name, version, value,
1935                                              symsize, type, binding,
1936                                              visibility, nonvis, only_if_ref,
1937                                              force_override);
1938 #else
1939       gold_unreachable();
1940 #endif
1941     }
1942   else
1943     gold_unreachable();
1944 }
1945
1946 // Define a symbol as a constant, sized version.
1947
1948 template<int size>
1949 Sized_symbol<size>*
1950 Symbol_table::do_define_as_constant(
1951     const char* name,
1952     const char* version,
1953     typename elfcpp::Elf_types<size>::Elf_Addr value,
1954     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1955     elfcpp::STT type,
1956     elfcpp::STB binding,
1957     elfcpp::STV visibility,
1958     unsigned char nonvis,
1959     bool only_if_ref,
1960     bool force_override)
1961 {
1962   Sized_symbol<size>* sym;
1963   Sized_symbol<size>* oldsym;
1964   bool resolve_oldsym;
1965
1966   if (parameters->target().is_big_endian())
1967     {
1968 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1969       sym = this->define_special_symbol<size, true>(&name, &version,
1970                                                     only_if_ref, &oldsym,
1971                                                     &resolve_oldsym);
1972 #else
1973       gold_unreachable();
1974 #endif
1975     }
1976   else
1977     {
1978 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1979       sym = this->define_special_symbol<size, false>(&name, &version,
1980                                                      only_if_ref, &oldsym,
1981                                                      &resolve_oldsym);
1982 #else
1983       gold_unreachable();
1984 #endif
1985     }
1986
1987   if (sym == NULL)
1988     return NULL;
1989
1990   sym->init_constant(name, version, value, symsize, type, binding, visibility,
1991                      nonvis);
1992
1993   if (oldsym == NULL)
1994     {
1995       // Version symbols are absolute symbols with name == version.
1996       // We don't want to force them to be local.
1997       if ((version == NULL
1998            || name != version
1999            || value != 0)
2000           && (binding == elfcpp::STB_LOCAL
2001               || this->version_script_.symbol_is_local(name)))
2002         this->force_local(sym);
2003       else if (version != NULL
2004                && (name != version || value != 0))
2005         sym->set_is_default();
2006       return sym;
2007     }
2008
2009   if (force_override || Symbol_table::should_override_with_special(oldsym))
2010     this->override_with_special(oldsym, sym);
2011
2012   if (resolve_oldsym)
2013     return sym;
2014   else
2015     {
2016       delete sym;
2017       return oldsym;
2018     }
2019 }
2020
2021 // Define a set of symbols in output sections.
2022
2023 void
2024 Symbol_table::define_symbols(const Layout* layout, int count,
2025                              const Define_symbol_in_section* p,
2026                              bool only_if_ref)
2027 {
2028   for (int i = 0; i < count; ++i, ++p)
2029     {
2030       Output_section* os = layout->find_output_section(p->output_section);
2031       if (os != NULL)
2032         this->define_in_output_data(p->name, NULL, os, p->value,
2033                                     p->size, p->type, p->binding,
2034                                     p->visibility, p->nonvis,
2035                                     p->offset_is_from_end,
2036                                     only_if_ref || p->only_if_ref);
2037       else
2038         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2039                                  p->binding, p->visibility, p->nonvis,
2040                                  only_if_ref || p->only_if_ref,
2041                                  false);
2042     }
2043 }
2044
2045 // Define a set of symbols in output segments.
2046
2047 void
2048 Symbol_table::define_symbols(const Layout* layout, int count,
2049                              const Define_symbol_in_segment* p,
2050                              bool only_if_ref)
2051 {
2052   for (int i = 0; i < count; ++i, ++p)
2053     {
2054       Output_segment* os = layout->find_output_segment(p->segment_type,
2055                                                        p->segment_flags_set,
2056                                                        p->segment_flags_clear);
2057       if (os != NULL)
2058         this->define_in_output_segment(p->name, NULL, os, p->value,
2059                                        p->size, p->type, p->binding,
2060                                        p->visibility, p->nonvis,
2061                                        p->offset_base,
2062                                        only_if_ref || p->only_if_ref);
2063       else
2064         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2065                                  p->binding, p->visibility, p->nonvis,
2066                                  only_if_ref || p->only_if_ref,
2067                                  false);
2068     }
2069 }
2070
2071 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2072 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2073 // the offset within POSD.
2074
2075 template<int size>
2076 void
2077 Symbol_table::define_with_copy_reloc(
2078     Sized_symbol<size>* csym,
2079     Output_data* posd,
2080     typename elfcpp::Elf_types<size>::Elf_Addr value)
2081 {
2082   gold_assert(csym->is_from_dynobj());
2083   gold_assert(!csym->is_copied_from_dynobj());
2084   Object* object = csym->object();
2085   gold_assert(object->is_dynamic());
2086   Dynobj* dynobj = static_cast<Dynobj*>(object);
2087
2088   // Our copied variable has to override any variable in a shared
2089   // library.
2090   elfcpp::STB binding = csym->binding();
2091   if (binding == elfcpp::STB_WEAK)
2092     binding = elfcpp::STB_GLOBAL;
2093
2094   this->define_in_output_data(csym->name(), csym->version(),
2095                               posd, value, csym->symsize(),
2096                               csym->type(), binding,
2097                               csym->visibility(), csym->nonvis(),
2098                               false, false);
2099
2100   csym->set_is_copied_from_dynobj();
2101   csym->set_needs_dynsym_entry();
2102
2103   this->copied_symbol_dynobjs_[csym] = dynobj;
2104
2105   // We have now defined all aliases, but we have not entered them all
2106   // in the copied_symbol_dynobjs_ map.
2107   if (csym->has_alias())
2108     {
2109       Symbol* sym = csym;
2110       while (true)
2111         {
2112           sym = this->weak_aliases_[sym];
2113           if (sym == csym)
2114             break;
2115           gold_assert(sym->output_data() == posd);
2116
2117           sym->set_is_copied_from_dynobj();
2118           this->copied_symbol_dynobjs_[sym] = dynobj;
2119         }
2120     }
2121 }
2122
2123 // SYM is defined using a COPY reloc.  Return the dynamic object where
2124 // the original definition was found.
2125
2126 Dynobj*
2127 Symbol_table::get_copy_source(const Symbol* sym) const
2128 {
2129   gold_assert(sym->is_copied_from_dynobj());
2130   Copied_symbol_dynobjs::const_iterator p =
2131     this->copied_symbol_dynobjs_.find(sym);
2132   gold_assert(p != this->copied_symbol_dynobjs_.end());
2133   return p->second;
2134 }
2135
2136 // Add any undefined symbols named on the command line.
2137
2138 void
2139 Symbol_table::add_undefined_symbols_from_command_line()
2140 {
2141   if (parameters->options().any_undefined())
2142     {
2143       if (parameters->target().get_size() == 32)
2144         {
2145 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2146           this->do_add_undefined_symbols_from_command_line<32>();
2147 #else
2148           gold_unreachable();
2149 #endif
2150         }
2151       else if (parameters->target().get_size() == 64)
2152         {
2153 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2154           this->do_add_undefined_symbols_from_command_line<64>();
2155 #else
2156           gold_unreachable();
2157 #endif
2158         }
2159       else
2160         gold_unreachable();
2161     }
2162 }
2163
2164 template<int size>
2165 void
2166 Symbol_table::do_add_undefined_symbols_from_command_line()
2167 {
2168   for (options::String_set::const_iterator p =
2169          parameters->options().undefined_begin();
2170        p != parameters->options().undefined_end();
2171        ++p)
2172     {
2173       const char* name = p->c_str();
2174
2175       if (this->lookup(name) != NULL)
2176         continue;
2177
2178       const char* version = NULL;
2179
2180       Sized_symbol<size>* sym;
2181       Sized_symbol<size>* oldsym;
2182       bool resolve_oldsym;
2183       if (parameters->target().is_big_endian())
2184         {
2185 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2186           sym = this->define_special_symbol<size, true>(&name, &version,
2187                                                         false, &oldsym,
2188                                                         &resolve_oldsym);
2189 #else
2190           gold_unreachable();
2191 #endif
2192         }
2193       else
2194         {
2195 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2196           sym = this->define_special_symbol<size, false>(&name, &version,
2197                                                          false, &oldsym,
2198                                                          &resolve_oldsym);
2199 #else
2200           gold_unreachable();
2201 #endif
2202         }
2203
2204       gold_assert(oldsym == NULL);
2205
2206       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2207                           elfcpp::STV_DEFAULT, 0);
2208       ++this->saw_undefined_;
2209     }
2210 }
2211
2212 // Set the dynamic symbol indexes.  INDEX is the index of the first
2213 // global dynamic symbol.  Pointers to the symbols are stored into the
2214 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2215 // updated dynamic symbol index.
2216
2217 unsigned int
2218 Symbol_table::set_dynsym_indexes(unsigned int index,
2219                                  std::vector<Symbol*>* syms,
2220                                  Stringpool* dynpool,
2221                                  Versions* versions)
2222 {
2223   for (Symbol_table_type::iterator p = this->table_.begin();
2224        p != this->table_.end();
2225        ++p)
2226     {
2227       Symbol* sym = p->second;
2228
2229       // Note that SYM may already have a dynamic symbol index, since
2230       // some symbols appear more than once in the symbol table, with
2231       // and without a version.
2232
2233       if (!sym->should_add_dynsym_entry())
2234         sym->set_dynsym_index(-1U);
2235       else if (!sym->has_dynsym_index())
2236         {
2237           sym->set_dynsym_index(index);
2238           ++index;
2239           syms->push_back(sym);
2240           dynpool->add(sym->name(), false, NULL);
2241
2242           // Record any version information.
2243           if (sym->version() != NULL)
2244             versions->record_version(this, dynpool, sym);
2245         }
2246     }
2247
2248   // Finish up the versions.  In some cases this may add new dynamic
2249   // symbols.
2250   index = versions->finalize(this, index, syms);
2251
2252   return index;
2253 }
2254
2255 // Set the final values for all the symbols.  The index of the first
2256 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2257 // file offset OFF.  Add their names to POOL.  Return the new file
2258 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2259
2260 off_t
2261 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2262                        size_t dyncount, Stringpool* pool,
2263                        unsigned int *plocal_symcount)
2264 {
2265   off_t ret;
2266
2267   gold_assert(*plocal_symcount != 0);
2268   this->first_global_index_ = *plocal_symcount;
2269
2270   this->dynamic_offset_ = dynoff;
2271   this->first_dynamic_global_index_ = dyn_global_index;
2272   this->dynamic_count_ = dyncount;
2273
2274   if (parameters->target().get_size() == 32)
2275     {
2276 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2277       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2278 #else
2279       gold_unreachable();
2280 #endif
2281     }
2282   else if (parameters->target().get_size() == 64)
2283     {
2284 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2285       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2286 #else
2287       gold_unreachable();
2288 #endif
2289     }
2290   else
2291     gold_unreachable();
2292
2293   // Now that we have the final symbol table, we can reliably note
2294   // which symbols should get warnings.
2295   this->warnings_.note_warnings(this);
2296
2297   return ret;
2298 }
2299
2300 // SYM is going into the symbol table at *PINDEX.  Add the name to
2301 // POOL, update *PINDEX and *POFF.
2302
2303 template<int size>
2304 void
2305 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2306                                   unsigned int* pindex, off_t* poff)
2307 {
2308   sym->set_symtab_index(*pindex);
2309   pool->add(sym->name(), false, NULL);
2310   ++*pindex;
2311   *poff += elfcpp::Elf_sizes<size>::sym_size;
2312 }
2313
2314 // Set the final value for all the symbols.  This is called after
2315 // Layout::finalize, so all the output sections have their final
2316 // address.
2317
2318 template<int size>
2319 off_t
2320 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2321                              unsigned int* plocal_symcount)
2322 {
2323   off = align_address(off, size >> 3);
2324   this->offset_ = off;
2325
2326   unsigned int index = *plocal_symcount;
2327   const unsigned int orig_index = index;
2328
2329   // First do all the symbols which have been forced to be local, as
2330   // they must appear before all global symbols.
2331   for (Forced_locals::iterator p = this->forced_locals_.begin();
2332        p != this->forced_locals_.end();
2333        ++p)
2334     {
2335       Symbol* sym = *p;
2336       gold_assert(sym->is_forced_local());
2337       if (this->sized_finalize_symbol<size>(sym))
2338         {
2339           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2340           ++*plocal_symcount;
2341         }
2342     }
2343
2344   // Now do all the remaining symbols.
2345   for (Symbol_table_type::iterator p = this->table_.begin();
2346        p != this->table_.end();
2347        ++p)
2348     {
2349       Symbol* sym = p->second;
2350       if (this->sized_finalize_symbol<size>(sym))
2351         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2352     }
2353
2354   this->output_count_ = index - orig_index;
2355
2356   return off;
2357 }
2358
2359 // Compute the final value of SYM and store status in location PSTATUS.
2360 // During relaxation, this may be called multiple times for a symbol to
2361 // compute its would-be final value in each relaxation pass.
2362
2363 template<int size>
2364 typename Sized_symbol<size>::Value_type
2365 Symbol_table::compute_final_value(
2366     const Sized_symbol<size>* sym,
2367     Compute_final_value_status* pstatus) const
2368 {
2369   typedef typename Sized_symbol<size>::Value_type Value_type;
2370   Value_type value;
2371
2372   switch (sym->source())
2373     {
2374     case Symbol::FROM_OBJECT:
2375       {
2376         bool is_ordinary;
2377         unsigned int shndx = sym->shndx(&is_ordinary);
2378
2379         if (!is_ordinary
2380             && shndx != elfcpp::SHN_ABS
2381             && !Symbol::is_common_shndx(shndx))
2382           {
2383             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2384             return 0;
2385           }
2386
2387         Object* symobj = sym->object();
2388         if (symobj->is_dynamic())
2389           {
2390             value = 0;
2391             shndx = elfcpp::SHN_UNDEF;
2392           }
2393         else if (symobj->pluginobj() != NULL)
2394           {
2395             value = 0;
2396             shndx = elfcpp::SHN_UNDEF;
2397           }
2398         else if (shndx == elfcpp::SHN_UNDEF)
2399           value = 0;
2400         else if (!is_ordinary
2401                  && (shndx == elfcpp::SHN_ABS
2402                      || Symbol::is_common_shndx(shndx)))
2403           value = sym->value();
2404         else
2405           {
2406             Relobj* relobj = static_cast<Relobj*>(symobj);
2407             Output_section* os = relobj->output_section(shndx);
2408             uint64_t secoff64 = relobj->output_section_offset(shndx);
2409
2410             if (this->is_section_folded(relobj, shndx))
2411               {
2412                 gold_assert(os == NULL);
2413                 // Get the os of the section it is folded onto.
2414                 Section_id folded = this->icf_->get_folded_section(relobj,
2415                                                                    shndx);
2416                 gold_assert(folded.first != NULL);
2417                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2418                 os = folded_obj->output_section(folded.second);  
2419                 gold_assert(os != NULL);
2420                 secoff64 = folded_obj->output_section_offset(folded.second);
2421               }
2422
2423             if (os == NULL)
2424               {
2425                 bool static_or_reloc = (parameters->doing_static_link() ||
2426                                         parameters->options().relocatable());
2427                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2428
2429                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2430                 return 0;
2431               }
2432
2433             if (secoff64 == -1ULL)
2434               {
2435                 // The section needs special handling (e.g., a merge section).
2436
2437                 value = os->output_address(relobj, shndx, sym->value());
2438               }
2439             else
2440               {
2441                 Value_type secoff =
2442                   convert_types<Value_type, uint64_t>(secoff64);
2443                 if (sym->type() == elfcpp::STT_TLS)
2444                   value = sym->value() + os->tls_offset() + secoff;
2445                 else
2446                   value = sym->value() + os->address() + secoff;
2447               }
2448           }
2449       }
2450       break;
2451
2452     case Symbol::IN_OUTPUT_DATA:
2453       {
2454         Output_data* od = sym->output_data();
2455         value = sym->value();
2456         if (sym->type() != elfcpp::STT_TLS)
2457           value += od->address();
2458         else
2459           {
2460             Output_section* os = od->output_section();
2461             gold_assert(os != NULL);
2462             value += os->tls_offset() + (od->address() - os->address());
2463           }
2464         if (sym->offset_is_from_end())
2465           value += od->data_size();
2466       }
2467       break;
2468
2469     case Symbol::IN_OUTPUT_SEGMENT:
2470       {
2471         Output_segment* os = sym->output_segment();
2472         value = sym->value();
2473         if (sym->type() != elfcpp::STT_TLS)
2474           value += os->vaddr();
2475         switch (sym->offset_base())
2476           {
2477           case Symbol::SEGMENT_START:
2478             break;
2479           case Symbol::SEGMENT_END:
2480             value += os->memsz();
2481             break;
2482           case Symbol::SEGMENT_BSS:
2483             value += os->filesz();
2484             break;
2485           default:
2486             gold_unreachable();
2487           }
2488       }
2489       break;
2490
2491     case Symbol::IS_CONSTANT:
2492       value = sym->value();
2493       break;
2494
2495     case Symbol::IS_UNDEFINED:
2496       value = 0;
2497       break;
2498
2499     default:
2500       gold_unreachable();
2501     }
2502
2503   *pstatus = CFVS_OK;
2504   return value;
2505 }
2506
2507 // Finalize the symbol SYM.  This returns true if the symbol should be
2508 // added to the symbol table, false otherwise.
2509
2510 template<int size>
2511 bool
2512 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2513 {
2514   typedef typename Sized_symbol<size>::Value_type Value_type;
2515
2516   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2517
2518   // The default version of a symbol may appear twice in the symbol
2519   // table.  We only need to finalize it once.
2520   if (sym->has_symtab_index())
2521     return false;
2522
2523   if (!sym->in_reg())
2524     {
2525       gold_assert(!sym->has_symtab_index());
2526       sym->set_symtab_index(-1U);
2527       gold_assert(sym->dynsym_index() == -1U);
2528       return false;
2529     }
2530
2531   // Compute final symbol value.
2532   Compute_final_value_status status;
2533   Value_type value = this->compute_final_value(sym, &status);
2534
2535   switch (status)
2536     {
2537     case CFVS_OK:
2538       break;
2539     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2540       {
2541         bool is_ordinary;
2542         unsigned int shndx = sym->shndx(&is_ordinary);
2543         gold_error(_("%s: unsupported symbol section 0x%x"),
2544                    sym->demangled_name().c_str(), shndx);
2545       }
2546       break;
2547     case CFVS_NO_OUTPUT_SECTION:
2548       sym->set_symtab_index(-1U);
2549       return false;
2550     default:
2551       gold_unreachable();
2552     }
2553
2554   sym->set_value(value);
2555
2556   if (parameters->options().strip_all()
2557       || !parameters->options().should_retain_symbol(sym->name()))
2558     {
2559       sym->set_symtab_index(-1U);
2560       return false;
2561     }
2562
2563   return true;
2564 }
2565
2566 // Write out the global symbols.
2567
2568 void
2569 Symbol_table::write_globals(const Stringpool* sympool,
2570                             const Stringpool* dynpool,
2571                             Output_symtab_xindex* symtab_xindex,
2572                             Output_symtab_xindex* dynsym_xindex,
2573                             Output_file* of) const
2574 {
2575   switch (parameters->size_and_endianness())
2576     {
2577 #ifdef HAVE_TARGET_32_LITTLE
2578     case Parameters::TARGET_32_LITTLE:
2579       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2580                                            dynsym_xindex, of);
2581       break;
2582 #endif
2583 #ifdef HAVE_TARGET_32_BIG
2584     case Parameters::TARGET_32_BIG:
2585       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2586                                           dynsym_xindex, of);
2587       break;
2588 #endif
2589 #ifdef HAVE_TARGET_64_LITTLE
2590     case Parameters::TARGET_64_LITTLE:
2591       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2592                                            dynsym_xindex, of);
2593       break;
2594 #endif
2595 #ifdef HAVE_TARGET_64_BIG
2596     case Parameters::TARGET_64_BIG:
2597       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2598                                           dynsym_xindex, of);
2599       break;
2600 #endif
2601     default:
2602       gold_unreachable();
2603     }
2604 }
2605
2606 // Write out the global symbols.
2607
2608 template<int size, bool big_endian>
2609 void
2610 Symbol_table::sized_write_globals(const Stringpool* sympool,
2611                                   const Stringpool* dynpool,
2612                                   Output_symtab_xindex* symtab_xindex,
2613                                   Output_symtab_xindex* dynsym_xindex,
2614                                   Output_file* of) const
2615 {
2616   const Target& target = parameters->target();
2617
2618   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2619
2620   const unsigned int output_count = this->output_count_;
2621   const section_size_type oview_size = output_count * sym_size;
2622   const unsigned int first_global_index = this->first_global_index_;
2623   unsigned char* psyms;
2624   if (this->offset_ == 0 || output_count == 0)
2625     psyms = NULL;
2626   else
2627     psyms = of->get_output_view(this->offset_, oview_size);
2628
2629   const unsigned int dynamic_count = this->dynamic_count_;
2630   const section_size_type dynamic_size = dynamic_count * sym_size;
2631   const unsigned int first_dynamic_global_index =
2632     this->first_dynamic_global_index_;
2633   unsigned char* dynamic_view;
2634   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2635     dynamic_view = NULL;
2636   else
2637     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2638
2639   for (Symbol_table_type::const_iterator p = this->table_.begin();
2640        p != this->table_.end();
2641        ++p)
2642     {
2643       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2644
2645       // Possibly warn about unresolved symbols in shared libraries.
2646       this->warn_about_undefined_dynobj_symbol(sym);
2647
2648       unsigned int sym_index = sym->symtab_index();
2649       unsigned int dynsym_index;
2650       if (dynamic_view == NULL)
2651         dynsym_index = -1U;
2652       else
2653         dynsym_index = sym->dynsym_index();
2654
2655       if (sym_index == -1U && dynsym_index == -1U)
2656         {
2657           // This symbol is not included in the output file.
2658           continue;
2659         }
2660
2661       unsigned int shndx;
2662       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2663       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2664       switch (sym->source())
2665         {
2666         case Symbol::FROM_OBJECT:
2667           {
2668             bool is_ordinary;
2669             unsigned int in_shndx = sym->shndx(&is_ordinary);
2670
2671             if (!is_ordinary
2672                 && in_shndx != elfcpp::SHN_ABS
2673                 && !Symbol::is_common_shndx(in_shndx))
2674               {
2675                 gold_error(_("%s: unsupported symbol section 0x%x"),
2676                            sym->demangled_name().c_str(), in_shndx);
2677                 shndx = in_shndx;
2678               }
2679             else
2680               {
2681                 Object* symobj = sym->object();
2682                 if (symobj->is_dynamic())
2683                   {
2684                     if (sym->needs_dynsym_value())
2685                       dynsym_value = target.dynsym_value(sym);
2686                     shndx = elfcpp::SHN_UNDEF;
2687                   }
2688                 else if (symobj->pluginobj() != NULL)
2689                   shndx = elfcpp::SHN_UNDEF;
2690                 else if (in_shndx == elfcpp::SHN_UNDEF
2691                          || (!is_ordinary
2692                              && (in_shndx == elfcpp::SHN_ABS
2693                                  || Symbol::is_common_shndx(in_shndx))))
2694                   shndx = in_shndx;
2695                 else
2696                   {
2697                     Relobj* relobj = static_cast<Relobj*>(symobj);
2698                     Output_section* os = relobj->output_section(in_shndx);
2699                     if (this->is_section_folded(relobj, in_shndx))
2700                       {
2701                         // This global symbol must be written out even though
2702                         // it is folded.
2703                         // Get the os of the section it is folded onto.
2704                         Section_id folded =
2705                              this->icf_->get_folded_section(relobj, in_shndx);
2706                         gold_assert(folded.first !=NULL);
2707                         Relobj* folded_obj = 
2708                           reinterpret_cast<Relobj*>(folded.first);
2709                         os = folded_obj->output_section(folded.second);  
2710                         gold_assert(os != NULL);
2711                       }
2712                     gold_assert(os != NULL);
2713                     shndx = os->out_shndx();
2714
2715                     if (shndx >= elfcpp::SHN_LORESERVE)
2716                       {
2717                         if (sym_index != -1U)
2718                           symtab_xindex->add(sym_index, shndx);
2719                         if (dynsym_index != -1U)
2720                           dynsym_xindex->add(dynsym_index, shndx);
2721                         shndx = elfcpp::SHN_XINDEX;
2722                       }
2723
2724                     // In object files symbol values are section
2725                     // relative.
2726                     if (parameters->options().relocatable())
2727                       sym_value -= os->address();
2728                   }
2729               }
2730           }
2731           break;
2732
2733         case Symbol::IN_OUTPUT_DATA:
2734           shndx = sym->output_data()->out_shndx();
2735           if (shndx >= elfcpp::SHN_LORESERVE)
2736             {
2737               if (sym_index != -1U)
2738                 symtab_xindex->add(sym_index, shndx);
2739               if (dynsym_index != -1U)
2740                 dynsym_xindex->add(dynsym_index, shndx);
2741               shndx = elfcpp::SHN_XINDEX;
2742             }
2743           break;
2744
2745         case Symbol::IN_OUTPUT_SEGMENT:
2746           shndx = elfcpp::SHN_ABS;
2747           break;
2748
2749         case Symbol::IS_CONSTANT:
2750           shndx = elfcpp::SHN_ABS;
2751           break;
2752
2753         case Symbol::IS_UNDEFINED:
2754           shndx = elfcpp::SHN_UNDEF;
2755           break;
2756
2757         default:
2758           gold_unreachable();
2759         }
2760
2761       if (sym_index != -1U)
2762         {
2763           sym_index -= first_global_index;
2764           gold_assert(sym_index < output_count);
2765           unsigned char* ps = psyms + (sym_index * sym_size);
2766           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2767                                                      sympool, ps);
2768         }
2769
2770       if (dynsym_index != -1U)
2771         {
2772           dynsym_index -= first_dynamic_global_index;
2773           gold_assert(dynsym_index < dynamic_count);
2774           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2775           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2776                                                      dynpool, pd);
2777         }
2778     }
2779
2780   of->write_output_view(this->offset_, oview_size, psyms);
2781   if (dynamic_view != NULL)
2782     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2783 }
2784
2785 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2786 // strtab holding the name.
2787
2788 template<int size, bool big_endian>
2789 void
2790 Symbol_table::sized_write_symbol(
2791     Sized_symbol<size>* sym,
2792     typename elfcpp::Elf_types<size>::Elf_Addr value,
2793     unsigned int shndx,
2794     const Stringpool* pool,
2795     unsigned char* p) const
2796 {
2797   elfcpp::Sym_write<size, big_endian> osym(p);
2798   osym.put_st_name(pool->get_offset(sym->name()));
2799   osym.put_st_value(value);
2800   // Use a symbol size of zero for undefined symbols from shared libraries.
2801   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2802     osym.put_st_size(0);
2803   else
2804     osym.put_st_size(sym->symsize());
2805   // A version script may have overridden the default binding.
2806   if (sym->is_forced_local())
2807     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, sym->type()));
2808   else
2809     osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type()));
2810   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2811   osym.put_st_shndx(shndx);
2812 }
2813
2814 // Check for unresolved symbols in shared libraries.  This is
2815 // controlled by the --allow-shlib-undefined option.
2816
2817 // We only warn about libraries for which we have seen all the
2818 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2819 // which were not seen in this link.  If we didn't see a DT_NEEDED
2820 // entry, we aren't going to be able to reliably report whether the
2821 // symbol is undefined.
2822
2823 // We also don't warn about libraries found in a system library
2824 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2825 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2826 // can have undefined references satisfied by ld-linux.so.
2827
2828 inline void
2829 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2830 {
2831   bool dummy;
2832   if (sym->source() == Symbol::FROM_OBJECT
2833       && sym->object()->is_dynamic()
2834       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2835       && sym->binding() != elfcpp::STB_WEAK
2836       && !parameters->options().allow_shlib_undefined()
2837       && !parameters->target().is_defined_by_abi(sym)
2838       && !sym->object()->is_in_system_directory())
2839     {
2840       // A very ugly cast.
2841       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2842       if (!dynobj->has_unknown_needed_entries())
2843         gold_undefined_symbol(sym);
2844     }
2845 }
2846
2847 // Write out a section symbol.  Return the update offset.
2848
2849 void
2850 Symbol_table::write_section_symbol(const Output_section *os,
2851                                    Output_symtab_xindex* symtab_xindex,
2852                                    Output_file* of,
2853                                    off_t offset) const
2854 {
2855   switch (parameters->size_and_endianness())
2856     {
2857 #ifdef HAVE_TARGET_32_LITTLE
2858     case Parameters::TARGET_32_LITTLE:
2859       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2860                                                   offset);
2861       break;
2862 #endif
2863 #ifdef HAVE_TARGET_32_BIG
2864     case Parameters::TARGET_32_BIG:
2865       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2866                                                  offset);
2867       break;
2868 #endif
2869 #ifdef HAVE_TARGET_64_LITTLE
2870     case Parameters::TARGET_64_LITTLE:
2871       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2872                                                   offset);
2873       break;
2874 #endif
2875 #ifdef HAVE_TARGET_64_BIG
2876     case Parameters::TARGET_64_BIG:
2877       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2878                                                  offset);
2879       break;
2880 #endif
2881     default:
2882       gold_unreachable();
2883     }
2884 }
2885
2886 // Write out a section symbol, specialized for size and endianness.
2887
2888 template<int size, bool big_endian>
2889 void
2890 Symbol_table::sized_write_section_symbol(const Output_section* os,
2891                                          Output_symtab_xindex* symtab_xindex,
2892                                          Output_file* of,
2893                                          off_t offset) const
2894 {
2895   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2896
2897   unsigned char* pov = of->get_output_view(offset, sym_size);
2898
2899   elfcpp::Sym_write<size, big_endian> osym(pov);
2900   osym.put_st_name(0);
2901   if (parameters->options().relocatable())
2902     osym.put_st_value(0);
2903   else
2904     osym.put_st_value(os->address());
2905   osym.put_st_size(0);
2906   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2907                                        elfcpp::STT_SECTION));
2908   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2909
2910   unsigned int shndx = os->out_shndx();
2911   if (shndx >= elfcpp::SHN_LORESERVE)
2912     {
2913       symtab_xindex->add(os->symtab_index(), shndx);
2914       shndx = elfcpp::SHN_XINDEX;
2915     }
2916   osym.put_st_shndx(shndx);
2917
2918   of->write_output_view(offset, sym_size, pov);
2919 }
2920
2921 // Print statistical information to stderr.  This is used for --stats.
2922
2923 void
2924 Symbol_table::print_stats() const
2925 {
2926 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2927   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2928           program_name, this->table_.size(), this->table_.bucket_count());
2929 #else
2930   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2931           program_name, this->table_.size());
2932 #endif
2933   this->namepool_.print_stats("symbol table stringpool");
2934 }
2935
2936 // We check for ODR violations by looking for symbols with the same
2937 // name for which the debugging information reports that they were
2938 // defined in different source locations.  When comparing the source
2939 // location, we consider instances with the same base filename and
2940 // line number to be the same.  This is because different object
2941 // files/shared libraries can include the same header file using
2942 // different paths, and we don't want to report an ODR violation in
2943 // that case.
2944
2945 // This struct is used to compare line information, as returned by
2946 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2947 // operator used with std::set.
2948
2949 struct Odr_violation_compare
2950 {
2951   bool
2952   operator()(const std::string& s1, const std::string& s2) const
2953   {
2954     std::string::size_type pos1 = s1.rfind('/');
2955     std::string::size_type pos2 = s2.rfind('/');
2956     if (pos1 == std::string::npos
2957         || pos2 == std::string::npos)
2958       return s1 < s2;
2959     return s1.compare(pos1, std::string::npos,
2960                       s2, pos2, std::string::npos) < 0;
2961   }
2962 };
2963
2964 // Check candidate_odr_violations_ to find symbols with the same name
2965 // but apparently different definitions (different source-file/line-no).
2966
2967 void
2968 Symbol_table::detect_odr_violations(const Task* task,
2969                                     const char* output_file_name) const
2970 {
2971   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2972        it != candidate_odr_violations_.end();
2973        ++it)
2974     {
2975       const char* symbol_name = it->first;
2976       // We use a sorted set so the output is deterministic.
2977       std::set<std::string, Odr_violation_compare> line_nums;
2978
2979       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
2980                locs = it->second.begin();
2981            locs != it->second.end();
2982            ++locs)
2983         {
2984           // We need to lock the object in order to read it.  This
2985           // means that we have to run in a singleton Task.  If we
2986           // want to run this in a general Task for better
2987           // performance, we will need one Task for object, plus
2988           // appropriate locking to ensure that we don't conflict with
2989           // other uses of the object.  Also note, one_addr2line is not
2990           // currently thread-safe.
2991           Task_lock_obj<Object> tl(task, locs->object);
2992           // 16 is the size of the object-cache that one_addr2line should use.
2993           std::string lineno = Dwarf_line_info::one_addr2line(
2994               locs->object, locs->shndx, locs->offset, 16);
2995           if (!lineno.empty())
2996             line_nums.insert(lineno);
2997         }
2998
2999       if (line_nums.size() > 1)
3000         {
3001           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3002                          "places (possible ODR violation):"),
3003                        output_file_name, demangle(symbol_name).c_str());
3004           for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3005                it2 != line_nums.end();
3006                ++it2)
3007             fprintf(stderr, "  %s\n", it2->c_str());
3008         }
3009     }
3010   // We only call one_addr2line() in this function, so we can clear its cache.
3011   Dwarf_line_info::clear_addr2line_cache();
3012 }
3013
3014 // Warnings functions.
3015
3016 // Add a new warning.
3017
3018 void
3019 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3020                       const std::string& warning)
3021 {
3022   name = symtab->canonicalize_name(name);
3023   this->warnings_[name].set(obj, warning);
3024 }
3025
3026 // Look through the warnings and mark the symbols for which we should
3027 // warn.  This is called during Layout::finalize when we know the
3028 // sources for all the symbols.
3029
3030 void
3031 Warnings::note_warnings(Symbol_table* symtab)
3032 {
3033   for (Warning_table::iterator p = this->warnings_.begin();
3034        p != this->warnings_.end();
3035        ++p)
3036     {
3037       Symbol* sym = symtab->lookup(p->first, NULL);
3038       if (sym != NULL
3039           && sym->source() == Symbol::FROM_OBJECT
3040           && sym->object() == p->second.object)
3041         sym->set_has_warning();
3042     }
3043 }
3044
3045 // Issue a warning.  This is called when we see a relocation against a
3046 // symbol for which has a warning.
3047
3048 template<int size, bool big_endian>
3049 void
3050 Warnings::issue_warning(const Symbol* sym,
3051                         const Relocate_info<size, big_endian>* relinfo,
3052                         size_t relnum, off_t reloffset) const
3053 {
3054   gold_assert(sym->has_warning());
3055   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3056   gold_assert(p != this->warnings_.end());
3057   gold_warning_at_location(relinfo, relnum, reloffset,
3058                            "%s", p->second.text.c_str());
3059 }
3060
3061 // Instantiate the templates we need.  We could use the configure
3062 // script to restrict this to only the ones needed for implemented
3063 // targets.
3064
3065 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3066 template
3067 void
3068 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3069 #endif
3070
3071 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3072 template
3073 void
3074 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3075 #endif
3076
3077 #ifdef HAVE_TARGET_32_LITTLE
3078 template
3079 void
3080 Symbol_table::add_from_relobj<32, false>(
3081     Sized_relobj<32, false>* relobj,
3082     const unsigned char* syms,
3083     size_t count,
3084     size_t symndx_offset,
3085     const char* sym_names,
3086     size_t sym_name_size,
3087     Sized_relobj<32, false>::Symbols* sympointers,
3088     size_t* defined);
3089 #endif
3090
3091 #ifdef HAVE_TARGET_32_BIG
3092 template
3093 void
3094 Symbol_table::add_from_relobj<32, true>(
3095     Sized_relobj<32, true>* relobj,
3096     const unsigned char* syms,
3097     size_t count,
3098     size_t symndx_offset,
3099     const char* sym_names,
3100     size_t sym_name_size,
3101     Sized_relobj<32, true>::Symbols* sympointers,
3102     size_t* defined);
3103 #endif
3104
3105 #ifdef HAVE_TARGET_64_LITTLE
3106 template
3107 void
3108 Symbol_table::add_from_relobj<64, false>(
3109     Sized_relobj<64, false>* relobj,
3110     const unsigned char* syms,
3111     size_t count,
3112     size_t symndx_offset,
3113     const char* sym_names,
3114     size_t sym_name_size,
3115     Sized_relobj<64, false>::Symbols* sympointers,
3116     size_t* defined);
3117 #endif
3118
3119 #ifdef HAVE_TARGET_64_BIG
3120 template
3121 void
3122 Symbol_table::add_from_relobj<64, true>(
3123     Sized_relobj<64, true>* relobj,
3124     const unsigned char* syms,
3125     size_t count,
3126     size_t symndx_offset,
3127     const char* sym_names,
3128     size_t sym_name_size,
3129     Sized_relobj<64, true>::Symbols* sympointers,
3130     size_t* defined);
3131 #endif
3132
3133 #ifdef HAVE_TARGET_32_LITTLE
3134 template
3135 Symbol*
3136 Symbol_table::add_from_pluginobj<32, false>(
3137     Sized_pluginobj<32, false>* obj,
3138     const char* name,
3139     const char* ver,
3140     elfcpp::Sym<32, false>* sym);
3141 #endif
3142
3143 #ifdef HAVE_TARGET_32_BIG
3144 template
3145 Symbol*
3146 Symbol_table::add_from_pluginobj<32, true>(
3147     Sized_pluginobj<32, true>* obj,
3148     const char* name,
3149     const char* ver,
3150     elfcpp::Sym<32, true>* sym);
3151 #endif
3152
3153 #ifdef HAVE_TARGET_64_LITTLE
3154 template
3155 Symbol*
3156 Symbol_table::add_from_pluginobj<64, false>(
3157     Sized_pluginobj<64, false>* obj,
3158     const char* name,
3159     const char* ver,
3160     elfcpp::Sym<64, false>* sym);
3161 #endif
3162
3163 #ifdef HAVE_TARGET_64_BIG
3164 template
3165 Symbol*
3166 Symbol_table::add_from_pluginobj<64, true>(
3167     Sized_pluginobj<64, true>* obj,
3168     const char* name,
3169     const char* ver,
3170     elfcpp::Sym<64, true>* sym);
3171 #endif
3172
3173 #ifdef HAVE_TARGET_32_LITTLE
3174 template
3175 void
3176 Symbol_table::add_from_dynobj<32, false>(
3177     Sized_dynobj<32, false>* dynobj,
3178     const unsigned char* syms,
3179     size_t count,
3180     const char* sym_names,
3181     size_t sym_name_size,
3182     const unsigned char* versym,
3183     size_t versym_size,
3184     const std::vector<const char*>* version_map,
3185     Sized_relobj<32, false>::Symbols* sympointers,
3186     size_t* defined);
3187 #endif
3188
3189 #ifdef HAVE_TARGET_32_BIG
3190 template
3191 void
3192 Symbol_table::add_from_dynobj<32, true>(
3193     Sized_dynobj<32, true>* dynobj,
3194     const unsigned char* syms,
3195     size_t count,
3196     const char* sym_names,
3197     size_t sym_name_size,
3198     const unsigned char* versym,
3199     size_t versym_size,
3200     const std::vector<const char*>* version_map,
3201     Sized_relobj<32, true>::Symbols* sympointers,
3202     size_t* defined);
3203 #endif
3204
3205 #ifdef HAVE_TARGET_64_LITTLE
3206 template
3207 void
3208 Symbol_table::add_from_dynobj<64, false>(
3209     Sized_dynobj<64, false>* dynobj,
3210     const unsigned char* syms,
3211     size_t count,
3212     const char* sym_names,
3213     size_t sym_name_size,
3214     const unsigned char* versym,
3215     size_t versym_size,
3216     const std::vector<const char*>* version_map,
3217     Sized_relobj<64, false>::Symbols* sympointers,
3218     size_t* defined);
3219 #endif
3220
3221 #ifdef HAVE_TARGET_64_BIG
3222 template
3223 void
3224 Symbol_table::add_from_dynobj<64, true>(
3225     Sized_dynobj<64, true>* dynobj,
3226     const unsigned char* syms,
3227     size_t count,
3228     const char* sym_names,
3229     size_t sym_name_size,
3230     const unsigned char* versym,
3231     size_t versym_size,
3232     const std::vector<const char*>* version_map,
3233     Sized_relobj<64, true>::Symbols* sympointers,
3234     size_t* defined);
3235 #endif
3236
3237 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3238 template
3239 void
3240 Symbol_table::define_with_copy_reloc<32>(
3241     Sized_symbol<32>* sym,
3242     Output_data* posd,
3243     elfcpp::Elf_types<32>::Elf_Addr value);
3244 #endif
3245
3246 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3247 template
3248 void
3249 Symbol_table::define_with_copy_reloc<64>(
3250     Sized_symbol<64>* sym,
3251     Output_data* posd,
3252     elfcpp::Elf_types<64>::Elf_Addr value);
3253 #endif
3254
3255 #ifdef HAVE_TARGET_32_LITTLE
3256 template
3257 void
3258 Warnings::issue_warning<32, false>(const Symbol* sym,
3259                                    const Relocate_info<32, false>* relinfo,
3260                                    size_t relnum, off_t reloffset) const;
3261 #endif
3262
3263 #ifdef HAVE_TARGET_32_BIG
3264 template
3265 void
3266 Warnings::issue_warning<32, true>(const Symbol* sym,
3267                                   const Relocate_info<32, true>* relinfo,
3268                                   size_t relnum, off_t reloffset) const;
3269 #endif
3270
3271 #ifdef HAVE_TARGET_64_LITTLE
3272 template
3273 void
3274 Warnings::issue_warning<64, false>(const Symbol* sym,
3275                                    const Relocate_info<64, false>* relinfo,
3276                                    size_t relnum, off_t reloffset) const;
3277 #endif
3278
3279 #ifdef HAVE_TARGET_64_BIG
3280 template
3281 void
3282 Warnings::issue_warning<64, true>(const Symbol* sym,
3283                                   const Relocate_info<64, true>* relinfo,
3284                                   size_t relnum, off_t reloffset) const;
3285 #endif
3286
3287 } // End namespace gold.