OSDN Git Service

2009-12-17 Rafael Avila de Espindola <espindola@google.com>
[pf3gnuchains/pf3gnuchains3x.git] / gold / symtab.cc
1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
32
33 #include "gc.h"
34 #include "object.h"
35 #include "dwarf_reader.h"
36 #include "dynobj.h"
37 #include "output.h"
38 #include "target.h"
39 #include "workqueue.h"
40 #include "symtab.h"
41 #include "demangle.h"   // needed for --dynamic-list-cpp-new
42 #include "plugin.h"
43
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol.  This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54                     elfcpp::STT type, elfcpp::STB binding,
55                     elfcpp::STV visibility, unsigned char nonvis)
56 {
57   this->name_ = name;
58   this->version_ = version;
59   this->symtab_index_ = 0;
60   this->dynsym_index_ = 0;
61   this->got_offsets_.init();
62   this->plt_offset_ = 0;
63   this->type_ = type;
64   this->binding_ = binding;
65   this->visibility_ = visibility;
66   this->nonvis_ = nonvis;
67   this->is_target_special_ = false;
68   this->is_def_ = false;
69   this->is_forwarder_ = false;
70   this->has_alias_ = false;
71   this->needs_dynsym_entry_ = false;
72   this->in_reg_ = false;
73   this->in_dyn_ = false;
74   this->has_plt_offset_ = false;
75   this->has_warning_ = false;
76   this->is_copied_from_dynobj_ = false;
77   this->is_forced_local_ = false;
78   this->is_ordinary_shndx_ = false;
79   this->in_real_elf_ = false;
80 }
81
82 // Return the demangled version of the symbol's name, but only
83 // if the --demangle flag was set.
84
85 static std::string
86 demangle(const char* name)
87 {
88   if (!parameters->options().do_demangle())
89     return name;
90
91   // cplus_demangle allocates memory for the result it returns,
92   // and returns NULL if the name is already demangled.
93   char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
94   if (demangled_name == NULL)
95     return name;
96
97   std::string retval(demangled_name);
98   free(demangled_name);
99   return retval;
100 }
101
102 std::string
103 Symbol::demangled_name() const
104 {
105   return demangle(this->name());
106 }
107
108 // Initialize the fields in the base class Symbol for SYM in OBJECT.
109
110 template<int size, bool big_endian>
111 void
112 Symbol::init_base_object(const char* name, const char* version, Object* object,
113                          const elfcpp::Sym<size, big_endian>& sym,
114                          unsigned int st_shndx, bool is_ordinary)
115 {
116   this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
117                     sym.get_st_visibility(), sym.get_st_nonvis());
118   this->u_.from_object.object = object;
119   this->u_.from_object.shndx = st_shndx;
120   this->is_ordinary_shndx_ = is_ordinary;
121   this->source_ = FROM_OBJECT;
122   this->in_reg_ = !object->is_dynamic();
123   this->in_dyn_ = object->is_dynamic();
124   this->in_real_elf_ = object->pluginobj() == NULL;
125 }
126
127 // Initialize the fields in the base class Symbol for a symbol defined
128 // in an Output_data.
129
130 void
131 Symbol::init_base_output_data(const char* name, const char* version,
132                               Output_data* od, elfcpp::STT type,
133                               elfcpp::STB binding, elfcpp::STV visibility,
134                               unsigned char nonvis, bool offset_is_from_end)
135 {
136   this->init_fields(name, version, type, binding, visibility, nonvis);
137   this->u_.in_output_data.output_data = od;
138   this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
139   this->source_ = IN_OUTPUT_DATA;
140   this->in_reg_ = true;
141   this->in_real_elf_ = true;
142 }
143
144 // Initialize the fields in the base class Symbol for a symbol defined
145 // in an Output_segment.
146
147 void
148 Symbol::init_base_output_segment(const char* name, const char* version,
149                                  Output_segment* os, elfcpp::STT type,
150                                  elfcpp::STB binding, elfcpp::STV visibility,
151                                  unsigned char nonvis,
152                                  Segment_offset_base offset_base)
153 {
154   this->init_fields(name, version, type, binding, visibility, nonvis);
155   this->u_.in_output_segment.output_segment = os;
156   this->u_.in_output_segment.offset_base = offset_base;
157   this->source_ = IN_OUTPUT_SEGMENT;
158   this->in_reg_ = true;
159   this->in_real_elf_ = true;
160 }
161
162 // Initialize the fields in the base class Symbol for a symbol defined
163 // as a constant.
164
165 void
166 Symbol::init_base_constant(const char* name, const char* version,
167                            elfcpp::STT type, elfcpp::STB binding,
168                            elfcpp::STV visibility, unsigned char nonvis)
169 {
170   this->init_fields(name, version, type, binding, visibility, nonvis);
171   this->source_ = IS_CONSTANT;
172   this->in_reg_ = true;
173   this->in_real_elf_ = true;
174 }
175
176 // Initialize the fields in the base class Symbol for an undefined
177 // symbol.
178
179 void
180 Symbol::init_base_undefined(const char* name, const char* version,
181                             elfcpp::STT type, elfcpp::STB binding,
182                             elfcpp::STV visibility, unsigned char nonvis)
183 {
184   this->init_fields(name, version, type, binding, visibility, nonvis);
185   this->dynsym_index_ = -1U;
186   this->source_ = IS_UNDEFINED;
187   this->in_reg_ = true;
188   this->in_real_elf_ = true;
189 }
190
191 // Allocate a common symbol in the base.
192
193 void
194 Symbol::allocate_base_common(Output_data* od)
195 {
196   gold_assert(this->is_common());
197   this->source_ = IN_OUTPUT_DATA;
198   this->u_.in_output_data.output_data = od;
199   this->u_.in_output_data.offset_is_from_end = false;
200 }
201
202 // Initialize the fields in Sized_symbol for SYM in OBJECT.
203
204 template<int size>
205 template<bool big_endian>
206 void
207 Sized_symbol<size>::init_object(const char* name, const char* version,
208                                 Object* object,
209                                 const elfcpp::Sym<size, big_endian>& sym,
210                                 unsigned int st_shndx, bool is_ordinary)
211 {
212   this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
213   this->value_ = sym.get_st_value();
214   this->symsize_ = sym.get_st_size();
215 }
216
217 // Initialize the fields in Sized_symbol for a symbol defined in an
218 // Output_data.
219
220 template<int size>
221 void
222 Sized_symbol<size>::init_output_data(const char* name, const char* version,
223                                      Output_data* od, Value_type value,
224                                      Size_type symsize, elfcpp::STT type,
225                                      elfcpp::STB binding,
226                                      elfcpp::STV visibility,
227                                      unsigned char nonvis,
228                                      bool offset_is_from_end)
229 {
230   this->init_base_output_data(name, version, od, type, binding, visibility,
231                               nonvis, offset_is_from_end);
232   this->value_ = value;
233   this->symsize_ = symsize;
234 }
235
236 // Initialize the fields in Sized_symbol for a symbol defined in an
237 // Output_segment.
238
239 template<int size>
240 void
241 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
242                                         Output_segment* os, Value_type value,
243                                         Size_type symsize, elfcpp::STT type,
244                                         elfcpp::STB binding,
245                                         elfcpp::STV visibility,
246                                         unsigned char nonvis,
247                                         Segment_offset_base offset_base)
248 {
249   this->init_base_output_segment(name, version, os, type, binding, visibility,
250                                  nonvis, offset_base);
251   this->value_ = value;
252   this->symsize_ = symsize;
253 }
254
255 // Initialize the fields in Sized_symbol for a symbol defined as a
256 // constant.
257
258 template<int size>
259 void
260 Sized_symbol<size>::init_constant(const char* name, const char* version,
261                                   Value_type value, Size_type symsize,
262                                   elfcpp::STT type, elfcpp::STB binding,
263                                   elfcpp::STV visibility, unsigned char nonvis)
264 {
265   this->init_base_constant(name, version, type, binding, visibility, nonvis);
266   this->value_ = value;
267   this->symsize_ = symsize;
268 }
269
270 // Initialize the fields in Sized_symbol for an undefined symbol.
271
272 template<int size>
273 void
274 Sized_symbol<size>::init_undefined(const char* name, const char* version,
275                                    elfcpp::STT type, elfcpp::STB binding,
276                                    elfcpp::STV visibility, unsigned char nonvis)
277 {
278   this->init_base_undefined(name, version, type, binding, visibility, nonvis);
279   this->value_ = 0;
280   this->symsize_ = 0;
281 }
282
283 // Return true if SHNDX represents a common symbol.
284
285 bool
286 Symbol::is_common_shndx(unsigned int shndx)
287 {
288   return (shndx == elfcpp::SHN_COMMON
289           || shndx == parameters->target().small_common_shndx()
290           || shndx == parameters->target().large_common_shndx());
291 }
292
293 // Allocate a common symbol.
294
295 template<int size>
296 void
297 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
298 {
299   this->allocate_base_common(od);
300   this->value_ = value;
301 }
302
303 // The ""'s around str ensure str is a string literal, so sizeof works.
304 #define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
305
306 // Return true if this symbol should be added to the dynamic symbol
307 // table.
308
309 inline bool
310 Symbol::should_add_dynsym_entry() const
311 {
312   // If the symbol is used by a dynamic relocation, we need to add it.
313   if (this->needs_dynsym_entry())
314     return true;
315
316   // If this symbol's section is not added, the symbol need not be added. 
317   // The section may have been GCed.  Note that export_dynamic is being 
318   // overridden here.  This should not be done for shared objects.
319   if (parameters->options().gc_sections() 
320       && !parameters->options().shared()
321       && this->source() == Symbol::FROM_OBJECT
322       && !this->object()->is_dynamic())
323     {
324       Relobj* relobj = static_cast<Relobj*>(this->object());
325       bool is_ordinary;
326       unsigned int shndx = this->shndx(&is_ordinary);
327       if (is_ordinary && shndx != elfcpp::SHN_UNDEF
328           && !relobj->is_section_included(shndx))
329         return false;
330     }
331
332   // If the symbol was forced local in a version script, do not add it.
333   if (this->is_forced_local())
334     return false;
335
336   // If the symbol was forced dynamic in a --dynamic-list file, add it.
337   if (parameters->options().in_dynamic_list(this->name()))
338     return true;
339
340   // If dynamic-list-data was specified, add any STT_OBJECT.
341   if (parameters->options().dynamic_list_data()
342       && !this->is_from_dynobj()
343       && this->type() == elfcpp::STT_OBJECT)
344     return true;
345
346   // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
347   // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
348   if ((parameters->options().dynamic_list_cpp_new()
349        || parameters->options().dynamic_list_cpp_typeinfo())
350       && !this->is_from_dynobj())
351     {
352       // TODO(csilvers): We could probably figure out if we're an operator
353       //                 new/delete or typeinfo without the need to demangle.
354       char* demangled_name = cplus_demangle(this->name(),
355                                             DMGL_ANSI | DMGL_PARAMS);
356       if (demangled_name == NULL)
357         {
358           // Not a C++ symbol, so it can't satisfy these flags
359         }
360       else if (parameters->options().dynamic_list_cpp_new()
361                && (strprefix(demangled_name, "operator new")
362                    || strprefix(demangled_name, "operator delete")))
363         {
364           free(demangled_name);
365           return true;
366         }
367       else if (parameters->options().dynamic_list_cpp_typeinfo()
368                && (strprefix(demangled_name, "typeinfo name for")
369                    || strprefix(demangled_name, "typeinfo for")))
370         {
371           free(demangled_name);
372           return true;
373         }
374       else
375         free(demangled_name);
376     }
377
378   // If exporting all symbols or building a shared library,
379   // and the symbol is defined in a regular object and is
380   // externally visible, we need to add it.
381   if ((parameters->options().export_dynamic() || parameters->options().shared())
382       && !this->is_from_dynobj()
383       && this->is_externally_visible())
384     return true;
385
386   return false;
387 }
388
389 // Return true if the final value of this symbol is known at link
390 // time.
391
392 bool
393 Symbol::final_value_is_known() const
394 {
395   // If we are not generating an executable, then no final values are
396   // known, since they will change at runtime.
397   if (parameters->options().output_is_position_independent()
398       || parameters->options().relocatable())
399     return false;
400
401   // If the symbol is not from an object file, and is not undefined,
402   // then it is defined, and known.
403   if (this->source_ != FROM_OBJECT)
404     {
405       if (this->source_ != IS_UNDEFINED)
406         return true;
407     }
408   else
409     {
410       // If the symbol is from a dynamic object, then the final value
411       // is not known.
412       if (this->object()->is_dynamic())
413         return false;
414
415       // If the symbol is not undefined (it is defined or common),
416       // then the final value is known.
417       if (!this->is_undefined())
418         return true;
419     }
420
421   // If the symbol is undefined, then whether the final value is known
422   // depends on whether we are doing a static link.  If we are doing a
423   // dynamic link, then the final value could be filled in at runtime.
424   // This could reasonably be the case for a weak undefined symbol.
425   return parameters->doing_static_link();
426 }
427
428 // Return the output section where this symbol is defined.
429
430 Output_section*
431 Symbol::output_section() const
432 {
433   switch (this->source_)
434     {
435     case FROM_OBJECT:
436       {
437         unsigned int shndx = this->u_.from_object.shndx;
438         if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
439           {
440             gold_assert(!this->u_.from_object.object->is_dynamic());
441             gold_assert(this->u_.from_object.object->pluginobj() == NULL);
442             Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
443             return relobj->output_section(shndx);
444           }
445         return NULL;
446       }
447
448     case IN_OUTPUT_DATA:
449       return this->u_.in_output_data.output_data->output_section();
450
451     case IN_OUTPUT_SEGMENT:
452     case IS_CONSTANT:
453     case IS_UNDEFINED:
454       return NULL;
455
456     default:
457       gold_unreachable();
458     }
459 }
460
461 // Set the symbol's output section.  This is used for symbols defined
462 // in scripts.  This should only be called after the symbol table has
463 // been finalized.
464
465 void
466 Symbol::set_output_section(Output_section* os)
467 {
468   switch (this->source_)
469     {
470     case FROM_OBJECT:
471     case IN_OUTPUT_DATA:
472       gold_assert(this->output_section() == os);
473       break;
474     case IS_CONSTANT:
475       this->source_ = IN_OUTPUT_DATA;
476       this->u_.in_output_data.output_data = os;
477       this->u_.in_output_data.offset_is_from_end = false;
478       break;
479     case IN_OUTPUT_SEGMENT:
480     case IS_UNDEFINED:
481     default:
482       gold_unreachable();
483     }
484 }
485
486 // Class Symbol_table.
487
488 Symbol_table::Symbol_table(unsigned int count,
489                            const Version_script_info& version_script)
490   : saw_undefined_(0), offset_(0), table_(count), namepool_(),
491     forwarders_(), commons_(), tls_commons_(), small_commons_(),
492     large_commons_(), forced_locals_(), warnings_(),
493     version_script_(version_script), gc_(NULL), icf_(NULL)
494 {
495   namepool_.reserve(count);
496 }
497
498 Symbol_table::~Symbol_table()
499 {
500 }
501
502 // The hash function.  The key values are Stringpool keys.
503
504 inline size_t
505 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
506 {
507   return key.first ^ key.second;
508 }
509
510 // The symbol table key equality function.  This is called with
511 // Stringpool keys.
512
513 inline bool
514 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
515                                           const Symbol_table_key& k2) const
516 {
517   return k1.first == k2.first && k1.second == k2.second;
518 }
519
520 bool
521 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
522 {
523   return (parameters->options().icf_enabled()
524           && this->icf_->is_section_folded(obj, shndx));
525 }
526
527 // For symbols that have been listed with -u option, add them to the
528 // work list to avoid gc'ing them.
529
530 void 
531 Symbol_table::gc_mark_undef_symbols()
532 {
533   for (options::String_set::const_iterator p =
534          parameters->options().undefined_begin();
535        p != parameters->options().undefined_end();
536        ++p)
537     {
538       const char* name = p->c_str();
539       Symbol* sym = this->lookup(name);
540       gold_assert (sym != NULL);
541       if (sym->source() == Symbol::FROM_OBJECT 
542           && !sym->object()->is_dynamic())
543         {
544           Relobj* obj = static_cast<Relobj*>(sym->object());
545           bool is_ordinary;
546           unsigned int shndx = sym->shndx(&is_ordinary);
547           if (is_ordinary)
548             {
549               gold_assert(this->gc_ != NULL);
550               this->gc_->worklist().push(Section_id(obj, shndx));
551             }
552         }
553     }
554 }
555
556 void
557 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
558 {
559   if (!sym->is_from_dynobj() 
560       && sym->is_externally_visible())
561     {
562       //Add the object and section to the work list.
563       Relobj* obj = static_cast<Relobj*>(sym->object());
564       bool is_ordinary;
565       unsigned int shndx = sym->shndx(&is_ordinary);
566       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
567         {
568           gold_assert(this->gc_!= NULL);
569           this->gc_->worklist().push(Section_id(obj, shndx));
570         }
571     }
572 }
573
574 // When doing garbage collection, keep symbols that have been seen in
575 // dynamic objects.
576 inline void 
577 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
578 {
579   if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
580       && !sym->object()->is_dynamic())
581     {
582       Relobj *obj = static_cast<Relobj*>(sym->object()); 
583       bool is_ordinary;
584       unsigned int shndx = sym->shndx(&is_ordinary);
585       if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
586         {
587           gold_assert(this->gc_ != NULL);
588           this->gc_->worklist().push(Section_id(obj, shndx));
589         }
590     }
591 }
592
593 // Make TO a symbol which forwards to FROM.
594
595 void
596 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
597 {
598   gold_assert(from != to);
599   gold_assert(!from->is_forwarder() && !to->is_forwarder());
600   this->forwarders_[from] = to;
601   from->set_forwarder();
602 }
603
604 // Resolve the forwards from FROM, returning the real symbol.
605
606 Symbol*
607 Symbol_table::resolve_forwards(const Symbol* from) const
608 {
609   gold_assert(from->is_forwarder());
610   Unordered_map<const Symbol*, Symbol*>::const_iterator p =
611     this->forwarders_.find(from);
612   gold_assert(p != this->forwarders_.end());
613   return p->second;
614 }
615
616 // Look up a symbol by name.
617
618 Symbol*
619 Symbol_table::lookup(const char* name, const char* version) const
620 {
621   Stringpool::Key name_key;
622   name = this->namepool_.find(name, &name_key);
623   if (name == NULL)
624     return NULL;
625
626   Stringpool::Key version_key = 0;
627   if (version != NULL)
628     {
629       version = this->namepool_.find(version, &version_key);
630       if (version == NULL)
631         return NULL;
632     }
633
634   Symbol_table_key key(name_key, version_key);
635   Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
636   if (p == this->table_.end())
637     return NULL;
638   return p->second;
639 }
640
641 // Resolve a Symbol with another Symbol.  This is only used in the
642 // unusual case where there are references to both an unversioned
643 // symbol and a symbol with a version, and we then discover that that
644 // version is the default version.  Because this is unusual, we do
645 // this the slow way, by converting back to an ELF symbol.
646
647 template<int size, bool big_endian>
648 void
649 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
650 {
651   unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
652   elfcpp::Sym_write<size, big_endian> esym(buf);
653   // We don't bother to set the st_name or the st_shndx field.
654   esym.put_st_value(from->value());
655   esym.put_st_size(from->symsize());
656   esym.put_st_info(from->binding(), from->type());
657   esym.put_st_other(from->visibility(), from->nonvis());
658   bool is_ordinary;
659   unsigned int shndx = from->shndx(&is_ordinary);
660   this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
661                 from->version());
662   if (from->in_reg())
663     to->set_in_reg();
664   if (from->in_dyn())
665     to->set_in_dyn();
666   if (parameters->options().gc_sections())
667     this->gc_mark_dyn_syms(to);
668 }
669
670 // Record that a symbol is forced to be local by a version script or
671 // by visibility.
672
673 void
674 Symbol_table::force_local(Symbol* sym)
675 {
676   if (!sym->is_defined() && !sym->is_common())
677     return;
678   if (sym->is_forced_local())
679     {
680       // We already got this one.
681       return;
682     }
683   sym->set_is_forced_local();
684   this->forced_locals_.push_back(sym);
685 }
686
687 // Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
688 // is only called for undefined symbols, when at least one --wrap
689 // option was used.
690
691 const char*
692 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
693 {
694   // For some targets, we need to ignore a specific character when
695   // wrapping, and add it back later.
696   char prefix = '\0';
697   if (name[0] == parameters->target().wrap_char())
698     {
699       prefix = name[0];
700       ++name;
701     }
702
703   if (parameters->options().is_wrap(name))
704     {
705       // Turn NAME into __wrap_NAME.
706       std::string s;
707       if (prefix != '\0')
708         s += prefix;
709       s += "__wrap_";
710       s += name;
711
712       // This will give us both the old and new name in NAMEPOOL_, but
713       // that is OK.  Only the versions we need will wind up in the
714       // real string table in the output file.
715       return this->namepool_.add(s.c_str(), true, name_key);
716     }
717
718   const char* const real_prefix = "__real_";
719   const size_t real_prefix_length = strlen(real_prefix);
720   if (strncmp(name, real_prefix, real_prefix_length) == 0
721       && parameters->options().is_wrap(name + real_prefix_length))
722     {
723       // Turn __real_NAME into NAME.
724       std::string s;
725       if (prefix != '\0')
726         s += prefix;
727       s += name + real_prefix_length;
728       return this->namepool_.add(s.c_str(), true, name_key);
729     }
730
731   return name;
732 }
733
734 // This is called when we see a symbol NAME/VERSION, and the symbol
735 // already exists in the symbol table, and VERSION is marked as being
736 // the default version.  SYM is the NAME/VERSION symbol we just added.
737 // DEFAULT_IS_NEW is true if this is the first time we have seen the
738 // symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
739
740 template<int size, bool big_endian>
741 void
742 Symbol_table::define_default_version(Sized_symbol<size>* sym,
743                                      bool default_is_new,
744                                      Symbol_table_type::iterator pdef)
745 {
746   if (default_is_new)
747     {
748       // This is the first time we have seen NAME/NULL.  Make
749       // NAME/NULL point to NAME/VERSION, and mark SYM as the default
750       // version.
751       pdef->second = sym;
752       sym->set_is_default();
753     }
754   else if (pdef->second == sym)
755     {
756       // NAME/NULL already points to NAME/VERSION.  Don't mark the
757       // symbol as the default if it is not already the default.
758     }
759   else
760     {
761       // This is the unfortunate case where we already have entries
762       // for both NAME/VERSION and NAME/NULL.  We now see a symbol
763       // NAME/VERSION where VERSION is the default version.  We have
764       // already resolved this new symbol with the existing
765       // NAME/VERSION symbol.
766
767       // It's possible that NAME/NULL and NAME/VERSION are both
768       // defined in regular objects.  This can only happen if one
769       // object file defines foo and another defines foo@@ver.  This
770       // is somewhat obscure, but we call it a multiple definition
771       // error.
772
773       // It's possible that NAME/NULL actually has a version, in which
774       // case it won't be the same as VERSION.  This happens with
775       // ver_test_7.so in the testsuite for the symbol t2_2.  We see
776       // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
777       // then see an unadorned t2_2 in an object file and give it
778       // version VER1 from the version script.  This looks like a
779       // default definition for VER1, so it looks like we should merge
780       // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
781       // not obvious that this is an error, either.  So we just punt.
782
783       // If one of the symbols has non-default visibility, and the
784       // other is defined in a shared object, then they are different
785       // symbols.
786
787       // Otherwise, we just resolve the symbols as though they were
788       // the same.
789
790       if (pdef->second->version() != NULL)
791         gold_assert(pdef->second->version() != sym->version());
792       else if (sym->visibility() != elfcpp::STV_DEFAULT
793                && pdef->second->is_from_dynobj())
794         ;
795       else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
796                && sym->is_from_dynobj())
797         ;
798       else
799         {
800           const Sized_symbol<size>* symdef;
801           symdef = this->get_sized_symbol<size>(pdef->second);
802           Symbol_table::resolve<size, big_endian>(sym, symdef);
803           this->make_forwarder(pdef->second, sym);
804           pdef->second = sym;
805           sym->set_is_default();
806         }
807     }
808 }
809
810 // Add one symbol from OBJECT to the symbol table.  NAME is symbol
811 // name and VERSION is the version; both are canonicalized.  DEF is
812 // whether this is the default version.  ST_SHNDX is the symbol's
813 // section index; IS_ORDINARY is whether this is a normal section
814 // rather than a special code.
815
816 // If DEF is true, then this is the definition of a default version of
817 // a symbol.  That means that any lookup of NAME/NULL and any lookup
818 // of NAME/VERSION should always return the same symbol.  This is
819 // obvious for references, but in particular we want to do this for
820 // definitions: overriding NAME/NULL should also override
821 // NAME/VERSION.  If we don't do that, it would be very hard to
822 // override functions in a shared library which uses versioning.
823
824 // We implement this by simply making both entries in the hash table
825 // point to the same Symbol structure.  That is easy enough if this is
826 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
827 // that we have seen both already, in which case they will both have
828 // independent entries in the symbol table.  We can't simply change
829 // the symbol table entry, because we have pointers to the entries
830 // attached to the object files.  So we mark the entry attached to the
831 // object file as a forwarder, and record it in the forwarders_ map.
832 // Note that entries in the hash table will never be marked as
833 // forwarders.
834 //
835 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
836 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
837 // for a special section code.  ST_SHNDX may be modified if the symbol
838 // is defined in a section being discarded.
839
840 template<int size, bool big_endian>
841 Sized_symbol<size>*
842 Symbol_table::add_from_object(Object* object,
843                               const char *name,
844                               Stringpool::Key name_key,
845                               const char *version,
846                               Stringpool::Key version_key,
847                               bool def,
848                               const elfcpp::Sym<size, big_endian>& sym,
849                               unsigned int st_shndx,
850                               bool is_ordinary,
851                               unsigned int orig_st_shndx)
852 {
853   // Print a message if this symbol is being traced.
854   if (parameters->options().is_trace_symbol(name))
855     {
856       if (orig_st_shndx == elfcpp::SHN_UNDEF)
857         gold_info(_("%s: reference to %s"), object->name().c_str(), name);
858       else
859         gold_info(_("%s: definition of %s"), object->name().c_str(), name);
860     }
861
862   // For an undefined symbol, we may need to adjust the name using
863   // --wrap.
864   if (orig_st_shndx == elfcpp::SHN_UNDEF
865       && parameters->options().any_wrap())
866     {
867       const char* wrap_name = this->wrap_symbol(name, &name_key);
868       if (wrap_name != name)
869         {
870           // If we see a reference to malloc with version GLIBC_2.0,
871           // and we turn it into a reference to __wrap_malloc, then we
872           // discard the version number.  Otherwise the user would be
873           // required to specify the correct version for
874           // __wrap_malloc.
875           version = NULL;
876           version_key = 0;
877           name = wrap_name;
878         }
879     }
880
881   Symbol* const snull = NULL;
882   std::pair<typename Symbol_table_type::iterator, bool> ins =
883     this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
884                                        snull));
885
886   std::pair<typename Symbol_table_type::iterator, bool> insdef =
887     std::make_pair(this->table_.end(), false);
888   if (def)
889     {
890       const Stringpool::Key vnull_key = 0;
891       insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
892                                                                  vnull_key),
893                                                   snull));
894     }
895
896   // ins.first: an iterator, which is a pointer to a pair.
897   // ins.first->first: the key (a pair of name and version).
898   // ins.first->second: the value (Symbol*).
899   // ins.second: true if new entry was inserted, false if not.
900
901   Sized_symbol<size>* ret;
902   bool was_undefined;
903   bool was_common;
904   if (!ins.second)
905     {
906       // We already have an entry for NAME/VERSION.
907       ret = this->get_sized_symbol<size>(ins.first->second);
908       gold_assert(ret != NULL);
909
910       was_undefined = ret->is_undefined();
911       was_common = ret->is_common();
912
913       this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
914                     version);
915       if (parameters->options().gc_sections())
916         this->gc_mark_dyn_syms(ret);
917
918       if (def)
919         this->define_default_version<size, big_endian>(ret, insdef.second,
920                                                        insdef.first);
921     }
922   else
923     {
924       // This is the first time we have seen NAME/VERSION.
925       gold_assert(ins.first->second == NULL);
926
927       if (def && !insdef.second)
928         {
929           // We already have an entry for NAME/NULL.  If we override
930           // it, then change it to NAME/VERSION.
931           ret = this->get_sized_symbol<size>(insdef.first->second);
932
933           was_undefined = ret->is_undefined();
934           was_common = ret->is_common();
935
936           this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
937                         version);
938           if (parameters->options().gc_sections())
939             this->gc_mark_dyn_syms(ret);
940           ins.first->second = ret;
941         }
942       else
943         {
944           was_undefined = false;
945           was_common = false;
946
947           Sized_target<size, big_endian>* target =
948             parameters->sized_target<size, big_endian>();
949           if (!target->has_make_symbol())
950             ret = new Sized_symbol<size>();
951           else
952             {
953               ret = target->make_symbol();
954               if (ret == NULL)
955                 {
956                   // This means that we don't want a symbol table
957                   // entry after all.
958                   if (!def)
959                     this->table_.erase(ins.first);
960                   else
961                     {
962                       this->table_.erase(insdef.first);
963                       // Inserting insdef invalidated ins.
964                       this->table_.erase(std::make_pair(name_key,
965                                                         version_key));
966                     }
967                   return NULL;
968                 }
969             }
970
971           ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
972
973           ins.first->second = ret;
974           if (def)
975             {
976               // This is the first time we have seen NAME/NULL.  Point
977               // it at the new entry for NAME/VERSION.
978               gold_assert(insdef.second);
979               insdef.first->second = ret;
980             }
981         }
982
983       if (def)
984         ret->set_is_default();
985     }
986
987   // Record every time we see a new undefined symbol, to speed up
988   // archive groups.
989   if (!was_undefined && ret->is_undefined())
990     ++this->saw_undefined_;
991
992   // Keep track of common symbols, to speed up common symbol
993   // allocation.
994   if (!was_common && ret->is_common())
995     {
996       if (ret->type() == elfcpp::STT_TLS)
997         this->tls_commons_.push_back(ret);
998       else if (!is_ordinary
999                && st_shndx == parameters->target().small_common_shndx())
1000         this->small_commons_.push_back(ret);
1001       else if (!is_ordinary
1002                && st_shndx == parameters->target().large_common_shndx())
1003         this->large_commons_.push_back(ret);
1004       else
1005         this->commons_.push_back(ret);
1006     }
1007
1008   // If we're not doing a relocatable link, then any symbol with
1009   // hidden or internal visibility is local.
1010   if ((ret->visibility() == elfcpp::STV_HIDDEN
1011        || ret->visibility() == elfcpp::STV_INTERNAL)
1012       && (ret->binding() == elfcpp::STB_GLOBAL
1013           || ret->binding() == elfcpp::STB_GNU_UNIQUE
1014           || ret->binding() == elfcpp::STB_WEAK)
1015       && !parameters->options().relocatable())
1016     this->force_local(ret);
1017
1018   return ret;
1019 }
1020
1021 // Add all the symbols in a relocatable object to the hash table.
1022
1023 template<int size, bool big_endian>
1024 void
1025 Symbol_table::add_from_relobj(
1026     Sized_relobj<size, big_endian>* relobj,
1027     const unsigned char* syms,
1028     size_t count,
1029     size_t symndx_offset,
1030     const char* sym_names,
1031     size_t sym_name_size,
1032     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1033     size_t *defined)
1034 {
1035   *defined = 0;
1036
1037   gold_assert(size == parameters->target().get_size());
1038
1039   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1040
1041   const bool just_symbols = relobj->just_symbols();
1042
1043   const unsigned char* p = syms;
1044   for (size_t i = 0; i < count; ++i, p += sym_size)
1045     {
1046       (*sympointers)[i] = NULL;
1047
1048       elfcpp::Sym<size, big_endian> sym(p);
1049
1050       unsigned int st_name = sym.get_st_name();
1051       if (st_name >= sym_name_size)
1052         {
1053           relobj->error(_("bad global symbol name offset %u at %zu"),
1054                         st_name, i);
1055           continue;
1056         }
1057
1058       const char* name = sym_names + st_name;
1059
1060       bool is_ordinary;
1061       unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1062                                                        sym.get_st_shndx(),
1063                                                        &is_ordinary);
1064       unsigned int orig_st_shndx = st_shndx;
1065       if (!is_ordinary)
1066         orig_st_shndx = elfcpp::SHN_UNDEF;
1067
1068       if (st_shndx != elfcpp::SHN_UNDEF)
1069         ++*defined;
1070
1071       // A symbol defined in a section which we are not including must
1072       // be treated as an undefined symbol.
1073       if (st_shndx != elfcpp::SHN_UNDEF
1074           && is_ordinary
1075           && !relobj->is_section_included(st_shndx))
1076         st_shndx = elfcpp::SHN_UNDEF;
1077
1078       // In an object file, an '@' in the name separates the symbol
1079       // name from the version name.  If there are two '@' characters,
1080       // this is the default version.
1081       const char* ver = strchr(name, '@');
1082       Stringpool::Key ver_key = 0;
1083       int namelen = 0;
1084       // DEF: is the version default?  LOCAL: is the symbol forced local?
1085       bool def = false;
1086       bool local = false;
1087
1088       if (ver != NULL)
1089         {
1090           // The symbol name is of the form foo@VERSION or foo@@VERSION
1091           namelen = ver - name;
1092           ++ver;
1093           if (*ver == '@')
1094             {
1095               def = true;
1096               ++ver;
1097             }
1098           ver = this->namepool_.add(ver, true, &ver_key);
1099         }
1100       // We don't want to assign a version to an undefined symbol,
1101       // even if it is listed in the version script.  FIXME: What
1102       // about a common symbol?
1103       else
1104         {
1105           namelen = strlen(name);
1106           if (!this->version_script_.empty()
1107               && st_shndx != elfcpp::SHN_UNDEF)
1108             {
1109               // The symbol name did not have a version, but the
1110               // version script may assign a version anyway.
1111               std::string version;
1112               if (this->version_script_.get_symbol_version(name, &version))
1113                 {
1114                   // The version can be empty if the version script is
1115                   // only used to force some symbols to be local.
1116                   if (!version.empty())
1117                     {
1118                       ver = this->namepool_.add_with_length(version.c_str(),
1119                                                             version.length(),
1120                                                             true,
1121                                                             &ver_key);
1122                       def = true;
1123                     }
1124                 }
1125               else if (this->version_script_.symbol_is_local(name))
1126                 local = true;
1127             }
1128         }
1129
1130       elfcpp::Sym<size, big_endian>* psym = &sym;
1131       unsigned char symbuf[sym_size];
1132       elfcpp::Sym<size, big_endian> sym2(symbuf);
1133       if (just_symbols)
1134         {
1135           memcpy(symbuf, p, sym_size);
1136           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1137           if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1138             {
1139               // Symbol values in object files are section relative.
1140               // This is normally what we want, but since here we are
1141               // converting the symbol to absolute we need to add the
1142               // section address.  The section address in an object
1143               // file is normally zero, but people can use a linker
1144               // script to change it.
1145               sw.put_st_value(sym.get_st_value()
1146                               + relobj->section_address(orig_st_shndx));
1147             }
1148           st_shndx = elfcpp::SHN_ABS;
1149           is_ordinary = false;
1150           psym = &sym2;
1151         }
1152
1153       // Fix up visibility if object has no-export set.
1154       if (relobj->no_export())
1155         {
1156           // We may have copied symbol already above.
1157           if (psym != &sym2)
1158             {
1159               memcpy(symbuf, p, sym_size);
1160               psym = &sym2;
1161             }
1162
1163           elfcpp::STV visibility = sym2.get_st_visibility();
1164           if (visibility == elfcpp::STV_DEFAULT
1165               || visibility == elfcpp::STV_PROTECTED)
1166             {
1167               elfcpp::Sym_write<size, big_endian> sw(symbuf);
1168               unsigned char nonvis = sym2.get_st_nonvis();
1169               sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1170             }
1171         }
1172
1173       Stringpool::Key name_key;
1174       name = this->namepool_.add_with_length(name, namelen, true,
1175                                              &name_key);
1176
1177       Sized_symbol<size>* res;
1178       res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1179                                   def, *psym, st_shndx, is_ordinary,
1180                                   orig_st_shndx);
1181       
1182       // If building a shared library using garbage collection, do not 
1183       // treat externally visible symbols as garbage.
1184       if (parameters->options().gc_sections() 
1185           && parameters->options().shared())
1186         this->gc_mark_symbol_for_shlib(res);
1187
1188       if (local)
1189         this->force_local(res);
1190
1191       (*sympointers)[i] = res;
1192     }
1193 }
1194
1195 // Add a symbol from a plugin-claimed file.
1196
1197 template<int size, bool big_endian>
1198 Symbol*
1199 Symbol_table::add_from_pluginobj(
1200     Sized_pluginobj<size, big_endian>* obj,
1201     const char* name,
1202     const char* ver,
1203     elfcpp::Sym<size, big_endian>* sym)
1204 {
1205   unsigned int st_shndx = sym->get_st_shndx();
1206   bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1207
1208   Stringpool::Key ver_key = 0;
1209   bool def = false;
1210   bool local = false;
1211
1212   if (ver != NULL)
1213     {
1214       ver = this->namepool_.add(ver, true, &ver_key);
1215     }
1216   // We don't want to assign a version to an undefined symbol,
1217   // even if it is listed in the version script.  FIXME: What
1218   // about a common symbol?
1219   else
1220     {
1221       if (!this->version_script_.empty()
1222           && st_shndx != elfcpp::SHN_UNDEF)
1223         {
1224           // The symbol name did not have a version, but the
1225           // version script may assign a version anyway.
1226           std::string version;
1227           if (this->version_script_.get_symbol_version(name, &version))
1228             {
1229               // The version can be empty if the version script is
1230               // only used to force some symbols to be local.
1231               if (!version.empty())
1232                 {
1233                   ver = this->namepool_.add_with_length(version.c_str(),
1234                                                         version.length(),
1235                                                         true,
1236                                                         &ver_key);
1237                   def = true;
1238                 }
1239             }
1240           else if (this->version_script_.symbol_is_local(name))
1241             local = true;
1242         }
1243     }
1244
1245   Stringpool::Key name_key;
1246   name = this->namepool_.add(name, true, &name_key);
1247
1248   Sized_symbol<size>* res;
1249   res = this->add_from_object(obj, name, name_key, ver, ver_key,
1250                               def, *sym, st_shndx, is_ordinary, st_shndx);
1251
1252   if (local)
1253     this->force_local(res);
1254
1255   return res;
1256 }
1257
1258 // Add all the symbols in a dynamic object to the hash table.
1259
1260 template<int size, bool big_endian>
1261 void
1262 Symbol_table::add_from_dynobj(
1263     Sized_dynobj<size, big_endian>* dynobj,
1264     const unsigned char* syms,
1265     size_t count,
1266     const char* sym_names,
1267     size_t sym_name_size,
1268     const unsigned char* versym,
1269     size_t versym_size,
1270     const std::vector<const char*>* version_map,
1271     typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1272     size_t* defined)
1273 {
1274   *defined = 0;
1275
1276   gold_assert(size == parameters->target().get_size());
1277
1278   if (dynobj->just_symbols())
1279     {
1280       gold_error(_("--just-symbols does not make sense with a shared object"));
1281       return;
1282     }
1283
1284   if (versym != NULL && versym_size / 2 < count)
1285     {
1286       dynobj->error(_("too few symbol versions"));
1287       return;
1288     }
1289
1290   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1291
1292   // We keep a list of all STT_OBJECT symbols, so that we can resolve
1293   // weak aliases.  This is necessary because if the dynamic object
1294   // provides the same variable under two names, one of which is a
1295   // weak definition, and the regular object refers to the weak
1296   // definition, we have to put both the weak definition and the
1297   // strong definition into the dynamic symbol table.  Given a weak
1298   // definition, the only way that we can find the corresponding
1299   // strong definition, if any, is to search the symbol table.
1300   std::vector<Sized_symbol<size>*> object_symbols;
1301
1302   const unsigned char* p = syms;
1303   const unsigned char* vs = versym;
1304   for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1305     {
1306       elfcpp::Sym<size, big_endian> sym(p);
1307
1308       if (sympointers != NULL)
1309         (*sympointers)[i] = NULL;
1310
1311       // Ignore symbols with local binding or that have
1312       // internal or hidden visibility.
1313       if (sym.get_st_bind() == elfcpp::STB_LOCAL
1314           || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1315           || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1316         continue;
1317
1318       // A protected symbol in a shared library must be treated as a
1319       // normal symbol when viewed from outside the shared library.
1320       // Implement this by overriding the visibility here.
1321       elfcpp::Sym<size, big_endian>* psym = &sym;
1322       unsigned char symbuf[sym_size];
1323       elfcpp::Sym<size, big_endian> sym2(symbuf);
1324       if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1325         {
1326           memcpy(symbuf, p, sym_size);
1327           elfcpp::Sym_write<size, big_endian> sw(symbuf);
1328           sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1329           psym = &sym2;
1330         }
1331
1332       unsigned int st_name = psym->get_st_name();
1333       if (st_name >= sym_name_size)
1334         {
1335           dynobj->error(_("bad symbol name offset %u at %zu"),
1336                         st_name, i);
1337           continue;
1338         }
1339
1340       const char* name = sym_names + st_name;
1341
1342       bool is_ordinary;
1343       unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1344                                                        &is_ordinary);
1345
1346       if (st_shndx != elfcpp::SHN_UNDEF)
1347         ++*defined;
1348
1349       Sized_symbol<size>* res;
1350
1351       if (versym == NULL)
1352         {
1353           Stringpool::Key name_key;
1354           name = this->namepool_.add(name, true, &name_key);
1355           res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1356                                       false, *psym, st_shndx, is_ordinary,
1357                                       st_shndx);
1358         }
1359       else
1360         {
1361           // Read the version information.
1362
1363           unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1364
1365           bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1366           v &= elfcpp::VERSYM_VERSION;
1367
1368           // The Sun documentation says that V can be VER_NDX_LOCAL,
1369           // or VER_NDX_GLOBAL, or a version index.  The meaning of
1370           // VER_NDX_LOCAL is defined as "Symbol has local scope."
1371           // The old GNU linker will happily generate VER_NDX_LOCAL
1372           // for an undefined symbol.  I don't know what the Sun
1373           // linker will generate.
1374
1375           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1376               && st_shndx != elfcpp::SHN_UNDEF)
1377             {
1378               // This symbol should not be visible outside the object.
1379               continue;
1380             }
1381
1382           // At this point we are definitely going to add this symbol.
1383           Stringpool::Key name_key;
1384           name = this->namepool_.add(name, true, &name_key);
1385
1386           if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1387               || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1388             {
1389               // This symbol does not have a version.
1390               res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1391                                           false, *psym, st_shndx, is_ordinary,
1392                                           st_shndx);
1393             }
1394           else
1395             {
1396               if (v >= version_map->size())
1397                 {
1398                   dynobj->error(_("versym for symbol %zu out of range: %u"),
1399                                 i, v);
1400                   continue;
1401                 }
1402
1403               const char* version = (*version_map)[v];
1404               if (version == NULL)
1405                 {
1406                   dynobj->error(_("versym for symbol %zu has no name: %u"),
1407                                 i, v);
1408                   continue;
1409                 }
1410
1411               Stringpool::Key version_key;
1412               version = this->namepool_.add(version, true, &version_key);
1413
1414               // If this is an absolute symbol, and the version name
1415               // and symbol name are the same, then this is the
1416               // version definition symbol.  These symbols exist to
1417               // support using -u to pull in particular versions.  We
1418               // do not want to record a version for them.
1419               if (st_shndx == elfcpp::SHN_ABS
1420                   && !is_ordinary
1421                   && name_key == version_key)
1422                 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1423                                             false, *psym, st_shndx, is_ordinary,
1424                                             st_shndx);
1425               else
1426                 {
1427                   const bool def = (!hidden
1428                                     && st_shndx != elfcpp::SHN_UNDEF);
1429                   res = this->add_from_object(dynobj, name, name_key, version,
1430                                               version_key, def, *psym, st_shndx,
1431                                               is_ordinary, st_shndx);
1432                 }
1433             }
1434         }
1435
1436       // Note that it is possible that RES was overridden by an
1437       // earlier object, in which case it can't be aliased here.
1438       if (st_shndx != elfcpp::SHN_UNDEF
1439           && is_ordinary
1440           && psym->get_st_type() == elfcpp::STT_OBJECT
1441           && res->source() == Symbol::FROM_OBJECT
1442           && res->object() == dynobj)
1443         object_symbols.push_back(res);
1444
1445       if (sympointers != NULL)
1446         (*sympointers)[i] = res;
1447     }
1448
1449   this->record_weak_aliases(&object_symbols);
1450 }
1451
1452 // This is used to sort weak aliases.  We sort them first by section
1453 // index, then by offset, then by weak ahead of strong.
1454
1455 template<int size>
1456 class Weak_alias_sorter
1457 {
1458  public:
1459   bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1460 };
1461
1462 template<int size>
1463 bool
1464 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1465                                     const Sized_symbol<size>* s2) const
1466 {
1467   bool is_ordinary;
1468   unsigned int s1_shndx = s1->shndx(&is_ordinary);
1469   gold_assert(is_ordinary);
1470   unsigned int s2_shndx = s2->shndx(&is_ordinary);
1471   gold_assert(is_ordinary);
1472   if (s1_shndx != s2_shndx)
1473     return s1_shndx < s2_shndx;
1474
1475   if (s1->value() != s2->value())
1476     return s1->value() < s2->value();
1477   if (s1->binding() != s2->binding())
1478     {
1479       if (s1->binding() == elfcpp::STB_WEAK)
1480         return true;
1481       if (s2->binding() == elfcpp::STB_WEAK)
1482         return false;
1483     }
1484   return std::string(s1->name()) < std::string(s2->name());
1485 }
1486
1487 // SYMBOLS is a list of object symbols from a dynamic object.  Look
1488 // for any weak aliases, and record them so that if we add the weak
1489 // alias to the dynamic symbol table, we also add the corresponding
1490 // strong symbol.
1491
1492 template<int size>
1493 void
1494 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1495 {
1496   // Sort the vector by section index, then by offset, then by weak
1497   // ahead of strong.
1498   std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1499
1500   // Walk through the vector.  For each weak definition, record
1501   // aliases.
1502   for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1503          symbols->begin();
1504        p != symbols->end();
1505        ++p)
1506     {
1507       if ((*p)->binding() != elfcpp::STB_WEAK)
1508         continue;
1509
1510       // Build a circular list of weak aliases.  Each symbol points to
1511       // the next one in the circular list.
1512
1513       Sized_symbol<size>* from_sym = *p;
1514       typename std::vector<Sized_symbol<size>*>::const_iterator q;
1515       for (q = p + 1; q != symbols->end(); ++q)
1516         {
1517           bool dummy;
1518           if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1519               || (*q)->value() != from_sym->value())
1520             break;
1521
1522           this->weak_aliases_[from_sym] = *q;
1523           from_sym->set_has_alias();
1524           from_sym = *q;
1525         }
1526
1527       if (from_sym != *p)
1528         {
1529           this->weak_aliases_[from_sym] = *p;
1530           from_sym->set_has_alias();
1531         }
1532
1533       p = q - 1;
1534     }
1535 }
1536
1537 // Create and return a specially defined symbol.  If ONLY_IF_REF is
1538 // true, then only create the symbol if there is a reference to it.
1539 // If this does not return NULL, it sets *POLDSYM to the existing
1540 // symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1541 // resolve the newly created symbol to the old one.  This
1542 // canonicalizes *PNAME and *PVERSION.
1543
1544 template<int size, bool big_endian>
1545 Sized_symbol<size>*
1546 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1547                                     bool only_if_ref,
1548                                     Sized_symbol<size>** poldsym,
1549                                     bool *resolve_oldsym)
1550 {
1551   *resolve_oldsym = false;
1552
1553   // If the caller didn't give us a version, see if we get one from
1554   // the version script.
1555   std::string v;
1556   bool is_default_version = false;
1557   if (*pversion == NULL)
1558     {
1559       if (this->version_script_.get_symbol_version(*pname, &v))
1560         {
1561           if (!v.empty())
1562             *pversion = v.c_str();
1563
1564           // If we get the version from a version script, then we are
1565           // also the default version.
1566           is_default_version = true;
1567         }
1568     }
1569
1570   Symbol* oldsym;
1571   Sized_symbol<size>* sym;
1572
1573   bool add_to_table = false;
1574   typename Symbol_table_type::iterator add_loc = this->table_.end();
1575   bool add_def_to_table = false;
1576   typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1577
1578   if (only_if_ref)
1579     {
1580       oldsym = this->lookup(*pname, *pversion);
1581       if (oldsym == NULL && is_default_version)
1582         oldsym = this->lookup(*pname, NULL);
1583       if (oldsym == NULL || !oldsym->is_undefined())
1584         return NULL;
1585
1586       *pname = oldsym->name();
1587       if (!is_default_version)
1588         *pversion = oldsym->version();
1589     }
1590   else
1591     {
1592       // Canonicalize NAME and VERSION.
1593       Stringpool::Key name_key;
1594       *pname = this->namepool_.add(*pname, true, &name_key);
1595
1596       Stringpool::Key version_key = 0;
1597       if (*pversion != NULL)
1598         *pversion = this->namepool_.add(*pversion, true, &version_key);
1599
1600       Symbol* const snull = NULL;
1601       std::pair<typename Symbol_table_type::iterator, bool> ins =
1602         this->table_.insert(std::make_pair(std::make_pair(name_key,
1603                                                           version_key),
1604                                            snull));
1605
1606       std::pair<typename Symbol_table_type::iterator, bool> insdef =
1607         std::make_pair(this->table_.end(), false);
1608       if (is_default_version)
1609         {
1610           const Stringpool::Key vnull = 0;
1611           insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
1612                                                                      vnull),
1613                                                       snull));
1614         }
1615
1616       if (!ins.second)
1617         {
1618           // We already have a symbol table entry for NAME/VERSION.
1619           oldsym = ins.first->second;
1620           gold_assert(oldsym != NULL);
1621
1622           if (is_default_version)
1623             {
1624               Sized_symbol<size>* soldsym =
1625                 this->get_sized_symbol<size>(oldsym);
1626               this->define_default_version<size, big_endian>(soldsym,
1627                                                              insdef.second,
1628                                                              insdef.first);
1629             }
1630         }
1631       else
1632         {
1633           // We haven't seen this symbol before.
1634           gold_assert(ins.first->second == NULL);
1635
1636           add_to_table = true;
1637           add_loc = ins.first;
1638
1639           if (is_default_version && !insdef.second)
1640             {
1641               // We are adding NAME/VERSION, and it is the default
1642               // version.  We already have an entry for NAME/NULL.
1643               oldsym = insdef.first->second;
1644               *resolve_oldsym = true;
1645             }
1646           else
1647             {
1648               oldsym = NULL;
1649
1650               if (is_default_version)
1651                 {
1652                   add_def_to_table = true;
1653                   add_def_loc = insdef.first;
1654                 }
1655             }
1656         }
1657     }
1658
1659   const Target& target = parameters->target();
1660   if (!target.has_make_symbol())
1661     sym = new Sized_symbol<size>();
1662   else
1663     {
1664       Sized_target<size, big_endian>* sized_target =
1665         parameters->sized_target<size, big_endian>();
1666       sym = sized_target->make_symbol();
1667       if (sym == NULL)
1668         return NULL;
1669     }
1670
1671   if (add_to_table)
1672     add_loc->second = sym;
1673   else
1674     gold_assert(oldsym != NULL);
1675
1676   if (add_def_to_table)
1677     add_def_loc->second = sym;
1678
1679   *poldsym = this->get_sized_symbol<size>(oldsym);
1680
1681   return sym;
1682 }
1683
1684 // Define a symbol based on an Output_data.
1685
1686 Symbol*
1687 Symbol_table::define_in_output_data(const char* name,
1688                                     const char* version,
1689                                     Output_data* od,
1690                                     uint64_t value,
1691                                     uint64_t symsize,
1692                                     elfcpp::STT type,
1693                                     elfcpp::STB binding,
1694                                     elfcpp::STV visibility,
1695                                     unsigned char nonvis,
1696                                     bool offset_is_from_end,
1697                                     bool only_if_ref)
1698 {
1699   if (parameters->target().get_size() == 32)
1700     {
1701 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1702       return this->do_define_in_output_data<32>(name, version, od,
1703                                                 value, symsize, type, binding,
1704                                                 visibility, nonvis,
1705                                                 offset_is_from_end,
1706                                                 only_if_ref);
1707 #else
1708       gold_unreachable();
1709 #endif
1710     }
1711   else if (parameters->target().get_size() == 64)
1712     {
1713 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1714       return this->do_define_in_output_data<64>(name, version, od,
1715                                                 value, symsize, type, binding,
1716                                                 visibility, nonvis,
1717                                                 offset_is_from_end,
1718                                                 only_if_ref);
1719 #else
1720       gold_unreachable();
1721 #endif
1722     }
1723   else
1724     gold_unreachable();
1725 }
1726
1727 // Define a symbol in an Output_data, sized version.
1728
1729 template<int size>
1730 Sized_symbol<size>*
1731 Symbol_table::do_define_in_output_data(
1732     const char* name,
1733     const char* version,
1734     Output_data* od,
1735     typename elfcpp::Elf_types<size>::Elf_Addr value,
1736     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1737     elfcpp::STT type,
1738     elfcpp::STB binding,
1739     elfcpp::STV visibility,
1740     unsigned char nonvis,
1741     bool offset_is_from_end,
1742     bool only_if_ref)
1743 {
1744   Sized_symbol<size>* sym;
1745   Sized_symbol<size>* oldsym;
1746   bool resolve_oldsym;
1747
1748   if (parameters->target().is_big_endian())
1749     {
1750 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1751       sym = this->define_special_symbol<size, true>(&name, &version,
1752                                                     only_if_ref, &oldsym,
1753                                                     &resolve_oldsym);
1754 #else
1755       gold_unreachable();
1756 #endif
1757     }
1758   else
1759     {
1760 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1761       sym = this->define_special_symbol<size, false>(&name, &version,
1762                                                      only_if_ref, &oldsym,
1763                                                      &resolve_oldsym);
1764 #else
1765       gold_unreachable();
1766 #endif
1767     }
1768
1769   if (sym == NULL)
1770     return NULL;
1771
1772   sym->init_output_data(name, version, od, value, symsize, type, binding,
1773                         visibility, nonvis, offset_is_from_end);
1774
1775   if (oldsym == NULL)
1776     {
1777       if (binding == elfcpp::STB_LOCAL
1778           || this->version_script_.symbol_is_local(name))
1779         this->force_local(sym);
1780       else if (version != NULL)
1781         sym->set_is_default();
1782       return sym;
1783     }
1784
1785   if (Symbol_table::should_override_with_special(oldsym))
1786     this->override_with_special(oldsym, sym);
1787
1788   if (resolve_oldsym)
1789     return sym;
1790   else
1791     {
1792       delete sym;
1793       return oldsym;
1794     }
1795 }
1796
1797 // Define a symbol based on an Output_segment.
1798
1799 Symbol*
1800 Symbol_table::define_in_output_segment(const char* name,
1801                                        const char* version, Output_segment* os,
1802                                        uint64_t value,
1803                                        uint64_t symsize,
1804                                        elfcpp::STT type,
1805                                        elfcpp::STB binding,
1806                                        elfcpp::STV visibility,
1807                                        unsigned char nonvis,
1808                                        Symbol::Segment_offset_base offset_base,
1809                                        bool only_if_ref)
1810 {
1811   if (parameters->target().get_size() == 32)
1812     {
1813 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1814       return this->do_define_in_output_segment<32>(name, version, os,
1815                                                    value, symsize, type,
1816                                                    binding, visibility, nonvis,
1817                                                    offset_base, only_if_ref);
1818 #else
1819       gold_unreachable();
1820 #endif
1821     }
1822   else if (parameters->target().get_size() == 64)
1823     {
1824 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1825       return this->do_define_in_output_segment<64>(name, version, os,
1826                                                    value, symsize, type,
1827                                                    binding, visibility, nonvis,
1828                                                    offset_base, only_if_ref);
1829 #else
1830       gold_unreachable();
1831 #endif
1832     }
1833   else
1834     gold_unreachable();
1835 }
1836
1837 // Define a symbol in an Output_segment, sized version.
1838
1839 template<int size>
1840 Sized_symbol<size>*
1841 Symbol_table::do_define_in_output_segment(
1842     const char* name,
1843     const char* version,
1844     Output_segment* os,
1845     typename elfcpp::Elf_types<size>::Elf_Addr value,
1846     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1847     elfcpp::STT type,
1848     elfcpp::STB binding,
1849     elfcpp::STV visibility,
1850     unsigned char nonvis,
1851     Symbol::Segment_offset_base offset_base,
1852     bool only_if_ref)
1853 {
1854   Sized_symbol<size>* sym;
1855   Sized_symbol<size>* oldsym;
1856   bool resolve_oldsym;
1857
1858   if (parameters->target().is_big_endian())
1859     {
1860 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1861       sym = this->define_special_symbol<size, true>(&name, &version,
1862                                                     only_if_ref, &oldsym,
1863                                                     &resolve_oldsym);
1864 #else
1865       gold_unreachable();
1866 #endif
1867     }
1868   else
1869     {
1870 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1871       sym = this->define_special_symbol<size, false>(&name, &version,
1872                                                      only_if_ref, &oldsym,
1873                                                      &resolve_oldsym);
1874 #else
1875       gold_unreachable();
1876 #endif
1877     }
1878
1879   if (sym == NULL)
1880     return NULL;
1881
1882   sym->init_output_segment(name, version, os, value, symsize, type, binding,
1883                            visibility, nonvis, offset_base);
1884
1885   if (oldsym == NULL)
1886     {
1887       if (binding == elfcpp::STB_LOCAL
1888           || this->version_script_.symbol_is_local(name))
1889         this->force_local(sym);
1890       else if (version != NULL)
1891         sym->set_is_default();
1892       return sym;
1893     }
1894
1895   if (Symbol_table::should_override_with_special(oldsym))
1896     this->override_with_special(oldsym, sym);
1897
1898   if (resolve_oldsym)
1899     return sym;
1900   else
1901     {
1902       delete sym;
1903       return oldsym;
1904     }
1905 }
1906
1907 // Define a special symbol with a constant value.  It is a multiple
1908 // definition error if this symbol is already defined.
1909
1910 Symbol*
1911 Symbol_table::define_as_constant(const char* name,
1912                                  const char* version,
1913                                  uint64_t value,
1914                                  uint64_t symsize,
1915                                  elfcpp::STT type,
1916                                  elfcpp::STB binding,
1917                                  elfcpp::STV visibility,
1918                                  unsigned char nonvis,
1919                                  bool only_if_ref,
1920                                  bool force_override)
1921 {
1922   if (parameters->target().get_size() == 32)
1923     {
1924 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1925       return this->do_define_as_constant<32>(name, version, value,
1926                                              symsize, type, binding,
1927                                              visibility, nonvis, only_if_ref,
1928                                              force_override);
1929 #else
1930       gold_unreachable();
1931 #endif
1932     }
1933   else if (parameters->target().get_size() == 64)
1934     {
1935 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1936       return this->do_define_as_constant<64>(name, version, value,
1937                                              symsize, type, binding,
1938                                              visibility, nonvis, only_if_ref,
1939                                              force_override);
1940 #else
1941       gold_unreachable();
1942 #endif
1943     }
1944   else
1945     gold_unreachable();
1946 }
1947
1948 // Define a symbol as a constant, sized version.
1949
1950 template<int size>
1951 Sized_symbol<size>*
1952 Symbol_table::do_define_as_constant(
1953     const char* name,
1954     const char* version,
1955     typename elfcpp::Elf_types<size>::Elf_Addr value,
1956     typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1957     elfcpp::STT type,
1958     elfcpp::STB binding,
1959     elfcpp::STV visibility,
1960     unsigned char nonvis,
1961     bool only_if_ref,
1962     bool force_override)
1963 {
1964   Sized_symbol<size>* sym;
1965   Sized_symbol<size>* oldsym;
1966   bool resolve_oldsym;
1967
1968   if (parameters->target().is_big_endian())
1969     {
1970 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1971       sym = this->define_special_symbol<size, true>(&name, &version,
1972                                                     only_if_ref, &oldsym,
1973                                                     &resolve_oldsym);
1974 #else
1975       gold_unreachable();
1976 #endif
1977     }
1978   else
1979     {
1980 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1981       sym = this->define_special_symbol<size, false>(&name, &version,
1982                                                      only_if_ref, &oldsym,
1983                                                      &resolve_oldsym);
1984 #else
1985       gold_unreachable();
1986 #endif
1987     }
1988
1989   if (sym == NULL)
1990     return NULL;
1991
1992   sym->init_constant(name, version, value, symsize, type, binding, visibility,
1993                      nonvis);
1994
1995   if (oldsym == NULL)
1996     {
1997       // Version symbols are absolute symbols with name == version.
1998       // We don't want to force them to be local.
1999       if ((version == NULL
2000            || name != version
2001            || value != 0)
2002           && (binding == elfcpp::STB_LOCAL
2003               || this->version_script_.symbol_is_local(name)))
2004         this->force_local(sym);
2005       else if (version != NULL
2006                && (name != version || value != 0))
2007         sym->set_is_default();
2008       return sym;
2009     }
2010
2011   if (force_override || Symbol_table::should_override_with_special(oldsym))
2012     this->override_with_special(oldsym, sym);
2013
2014   if (resolve_oldsym)
2015     return sym;
2016   else
2017     {
2018       delete sym;
2019       return oldsym;
2020     }
2021 }
2022
2023 // Define a set of symbols in output sections.
2024
2025 void
2026 Symbol_table::define_symbols(const Layout* layout, int count,
2027                              const Define_symbol_in_section* p,
2028                              bool only_if_ref)
2029 {
2030   for (int i = 0; i < count; ++i, ++p)
2031     {
2032       Output_section* os = layout->find_output_section(p->output_section);
2033       if (os != NULL)
2034         this->define_in_output_data(p->name, NULL, os, p->value,
2035                                     p->size, p->type, p->binding,
2036                                     p->visibility, p->nonvis,
2037                                     p->offset_is_from_end,
2038                                     only_if_ref || p->only_if_ref);
2039       else
2040         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2041                                  p->binding, p->visibility, p->nonvis,
2042                                  only_if_ref || p->only_if_ref,
2043                                  false);
2044     }
2045 }
2046
2047 // Define a set of symbols in output segments.
2048
2049 void
2050 Symbol_table::define_symbols(const Layout* layout, int count,
2051                              const Define_symbol_in_segment* p,
2052                              bool only_if_ref)
2053 {
2054   for (int i = 0; i < count; ++i, ++p)
2055     {
2056       Output_segment* os = layout->find_output_segment(p->segment_type,
2057                                                        p->segment_flags_set,
2058                                                        p->segment_flags_clear);
2059       if (os != NULL)
2060         this->define_in_output_segment(p->name, NULL, os, p->value,
2061                                        p->size, p->type, p->binding,
2062                                        p->visibility, p->nonvis,
2063                                        p->offset_base,
2064                                        only_if_ref || p->only_if_ref);
2065       else
2066         this->define_as_constant(p->name, NULL, 0, p->size, p->type,
2067                                  p->binding, p->visibility, p->nonvis,
2068                                  only_if_ref || p->only_if_ref,
2069                                  false);
2070     }
2071 }
2072
2073 // Define CSYM using a COPY reloc.  POSD is the Output_data where the
2074 // symbol should be defined--typically a .dyn.bss section.  VALUE is
2075 // the offset within POSD.
2076
2077 template<int size>
2078 void
2079 Symbol_table::define_with_copy_reloc(
2080     Sized_symbol<size>* csym,
2081     Output_data* posd,
2082     typename elfcpp::Elf_types<size>::Elf_Addr value)
2083 {
2084   gold_assert(csym->is_from_dynobj());
2085   gold_assert(!csym->is_copied_from_dynobj());
2086   Object* object = csym->object();
2087   gold_assert(object->is_dynamic());
2088   Dynobj* dynobj = static_cast<Dynobj*>(object);
2089
2090   // Our copied variable has to override any variable in a shared
2091   // library.
2092   elfcpp::STB binding = csym->binding();
2093   if (binding == elfcpp::STB_WEAK)
2094     binding = elfcpp::STB_GLOBAL;
2095
2096   this->define_in_output_data(csym->name(), csym->version(),
2097                               posd, value, csym->symsize(),
2098                               csym->type(), binding,
2099                               csym->visibility(), csym->nonvis(),
2100                               false, false);
2101
2102   csym->set_is_copied_from_dynobj();
2103   csym->set_needs_dynsym_entry();
2104
2105   this->copied_symbol_dynobjs_[csym] = dynobj;
2106
2107   // We have now defined all aliases, but we have not entered them all
2108   // in the copied_symbol_dynobjs_ map.
2109   if (csym->has_alias())
2110     {
2111       Symbol* sym = csym;
2112       while (true)
2113         {
2114           sym = this->weak_aliases_[sym];
2115           if (sym == csym)
2116             break;
2117           gold_assert(sym->output_data() == posd);
2118
2119           sym->set_is_copied_from_dynobj();
2120           this->copied_symbol_dynobjs_[sym] = dynobj;
2121         }
2122     }
2123 }
2124
2125 // SYM is defined using a COPY reloc.  Return the dynamic object where
2126 // the original definition was found.
2127
2128 Dynobj*
2129 Symbol_table::get_copy_source(const Symbol* sym) const
2130 {
2131   gold_assert(sym->is_copied_from_dynobj());
2132   Copied_symbol_dynobjs::const_iterator p =
2133     this->copied_symbol_dynobjs_.find(sym);
2134   gold_assert(p != this->copied_symbol_dynobjs_.end());
2135   return p->second;
2136 }
2137
2138 // Add any undefined symbols named on the command line.
2139
2140 void
2141 Symbol_table::add_undefined_symbols_from_command_line()
2142 {
2143   if (parameters->options().any_undefined())
2144     {
2145       if (parameters->target().get_size() == 32)
2146         {
2147 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2148           this->do_add_undefined_symbols_from_command_line<32>();
2149 #else
2150           gold_unreachable();
2151 #endif
2152         }
2153       else if (parameters->target().get_size() == 64)
2154         {
2155 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2156           this->do_add_undefined_symbols_from_command_line<64>();
2157 #else
2158           gold_unreachable();
2159 #endif
2160         }
2161       else
2162         gold_unreachable();
2163     }
2164 }
2165
2166 template<int size>
2167 void
2168 Symbol_table::do_add_undefined_symbols_from_command_line()
2169 {
2170   for (options::String_set::const_iterator p =
2171          parameters->options().undefined_begin();
2172        p != parameters->options().undefined_end();
2173        ++p)
2174     {
2175       const char* name = p->c_str();
2176
2177       if (this->lookup(name) != NULL)
2178         continue;
2179
2180       const char* version = NULL;
2181
2182       Sized_symbol<size>* sym;
2183       Sized_symbol<size>* oldsym;
2184       bool resolve_oldsym;
2185       if (parameters->target().is_big_endian())
2186         {
2187 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2188           sym = this->define_special_symbol<size, true>(&name, &version,
2189                                                         false, &oldsym,
2190                                                         &resolve_oldsym);
2191 #else
2192           gold_unreachable();
2193 #endif
2194         }
2195       else
2196         {
2197 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2198           sym = this->define_special_symbol<size, false>(&name, &version,
2199                                                          false, &oldsym,
2200                                                          &resolve_oldsym);
2201 #else
2202           gold_unreachable();
2203 #endif
2204         }
2205
2206       gold_assert(oldsym == NULL);
2207
2208       sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2209                           elfcpp::STV_DEFAULT, 0);
2210       ++this->saw_undefined_;
2211     }
2212 }
2213
2214 // Set the dynamic symbol indexes.  INDEX is the index of the first
2215 // global dynamic symbol.  Pointers to the symbols are stored into the
2216 // vector SYMS.  The names are added to DYNPOOL.  This returns an
2217 // updated dynamic symbol index.
2218
2219 unsigned int
2220 Symbol_table::set_dynsym_indexes(unsigned int index,
2221                                  std::vector<Symbol*>* syms,
2222                                  Stringpool* dynpool,
2223                                  Versions* versions)
2224 {
2225   for (Symbol_table_type::iterator p = this->table_.begin();
2226        p != this->table_.end();
2227        ++p)
2228     {
2229       Symbol* sym = p->second;
2230
2231       // Note that SYM may already have a dynamic symbol index, since
2232       // some symbols appear more than once in the symbol table, with
2233       // and without a version.
2234
2235       if (!sym->should_add_dynsym_entry())
2236         sym->set_dynsym_index(-1U);
2237       else if (!sym->has_dynsym_index())
2238         {
2239           sym->set_dynsym_index(index);
2240           ++index;
2241           syms->push_back(sym);
2242           dynpool->add(sym->name(), false, NULL);
2243
2244           // Record any version information.
2245           if (sym->version() != NULL)
2246             versions->record_version(this, dynpool, sym);
2247
2248           // If the symbol is defined in a dynamic object and is
2249           // referenced in a regular object, then mark the dynamic
2250           // object as needed.  This is used to implement --as-needed.
2251           if (sym->is_from_dynobj() && sym->in_reg())
2252             sym->object()->set_is_needed();
2253         }
2254     }
2255
2256   // Finish up the versions.  In some cases this may add new dynamic
2257   // symbols.
2258   index = versions->finalize(this, index, syms);
2259
2260   return index;
2261 }
2262
2263 // Set the final values for all the symbols.  The index of the first
2264 // global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2265 // file offset OFF.  Add their names to POOL.  Return the new file
2266 // offset.  Update *PLOCAL_SYMCOUNT if necessary.
2267
2268 off_t
2269 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2270                        size_t dyncount, Stringpool* pool,
2271                        unsigned int *plocal_symcount)
2272 {
2273   off_t ret;
2274
2275   gold_assert(*plocal_symcount != 0);
2276   this->first_global_index_ = *plocal_symcount;
2277
2278   this->dynamic_offset_ = dynoff;
2279   this->first_dynamic_global_index_ = dyn_global_index;
2280   this->dynamic_count_ = dyncount;
2281
2282   if (parameters->target().get_size() == 32)
2283     {
2284 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2285       ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2286 #else
2287       gold_unreachable();
2288 #endif
2289     }
2290   else if (parameters->target().get_size() == 64)
2291     {
2292 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2293       ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2294 #else
2295       gold_unreachable();
2296 #endif
2297     }
2298   else
2299     gold_unreachable();
2300
2301   // Now that we have the final symbol table, we can reliably note
2302   // which symbols should get warnings.
2303   this->warnings_.note_warnings(this);
2304
2305   return ret;
2306 }
2307
2308 // SYM is going into the symbol table at *PINDEX.  Add the name to
2309 // POOL, update *PINDEX and *POFF.
2310
2311 template<int size>
2312 void
2313 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2314                                   unsigned int* pindex, off_t* poff)
2315 {
2316   sym->set_symtab_index(*pindex);
2317   pool->add(sym->name(), false, NULL);
2318   ++*pindex;
2319   *poff += elfcpp::Elf_sizes<size>::sym_size;
2320 }
2321
2322 // Set the final value for all the symbols.  This is called after
2323 // Layout::finalize, so all the output sections have their final
2324 // address.
2325
2326 template<int size>
2327 off_t
2328 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2329                              unsigned int* plocal_symcount)
2330 {
2331   off = align_address(off, size >> 3);
2332   this->offset_ = off;
2333
2334   unsigned int index = *plocal_symcount;
2335   const unsigned int orig_index = index;
2336
2337   // First do all the symbols which have been forced to be local, as
2338   // they must appear before all global symbols.
2339   for (Forced_locals::iterator p = this->forced_locals_.begin();
2340        p != this->forced_locals_.end();
2341        ++p)
2342     {
2343       Symbol* sym = *p;
2344       gold_assert(sym->is_forced_local());
2345       if (this->sized_finalize_symbol<size>(sym))
2346         {
2347           this->add_to_final_symtab<size>(sym, pool, &index, &off);
2348           ++*plocal_symcount;
2349         }
2350     }
2351
2352   // Now do all the remaining symbols.
2353   for (Symbol_table_type::iterator p = this->table_.begin();
2354        p != this->table_.end();
2355        ++p)
2356     {
2357       Symbol* sym = p->second;
2358       if (this->sized_finalize_symbol<size>(sym))
2359         this->add_to_final_symtab<size>(sym, pool, &index, &off);
2360     }
2361
2362   this->output_count_ = index - orig_index;
2363
2364   return off;
2365 }
2366
2367 // Compute the final value of SYM and store status in location PSTATUS.
2368 // During relaxation, this may be called multiple times for a symbol to
2369 // compute its would-be final value in each relaxation pass.
2370
2371 template<int size>
2372 typename Sized_symbol<size>::Value_type
2373 Symbol_table::compute_final_value(
2374     const Sized_symbol<size>* sym,
2375     Compute_final_value_status* pstatus) const
2376 {
2377   typedef typename Sized_symbol<size>::Value_type Value_type;
2378   Value_type value;
2379
2380   switch (sym->source())
2381     {
2382     case Symbol::FROM_OBJECT:
2383       {
2384         bool is_ordinary;
2385         unsigned int shndx = sym->shndx(&is_ordinary);
2386
2387         if (!is_ordinary
2388             && shndx != elfcpp::SHN_ABS
2389             && !Symbol::is_common_shndx(shndx))
2390           {
2391             *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2392             return 0;
2393           }
2394
2395         Object* symobj = sym->object();
2396         if (symobj->is_dynamic())
2397           {
2398             value = 0;
2399             shndx = elfcpp::SHN_UNDEF;
2400           }
2401         else if (symobj->pluginobj() != NULL)
2402           {
2403             value = 0;
2404             shndx = elfcpp::SHN_UNDEF;
2405           }
2406         else if (shndx == elfcpp::SHN_UNDEF)
2407           value = 0;
2408         else if (!is_ordinary
2409                  && (shndx == elfcpp::SHN_ABS
2410                      || Symbol::is_common_shndx(shndx)))
2411           value = sym->value();
2412         else
2413           {
2414             Relobj* relobj = static_cast<Relobj*>(symobj);
2415             Output_section* os = relobj->output_section(shndx);
2416
2417             if (this->is_section_folded(relobj, shndx))
2418               {
2419                 gold_assert(os == NULL);
2420                 // Get the os of the section it is folded onto.
2421                 Section_id folded = this->icf_->get_folded_section(relobj,
2422                                                                    shndx);
2423                 gold_assert(folded.first != NULL);
2424                 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2425                 unsigned folded_shndx = folded.second;
2426
2427                 os = folded_obj->output_section(folded_shndx);  
2428                 gold_assert(os != NULL);
2429
2430                 // Replace (relobj, shndx) with canonical ICF input section.
2431                 shndx = folded_shndx;
2432                 relobj = folded_obj;
2433               }
2434
2435             uint64_t secoff64 = relobj->output_section_offset(shndx);
2436             if (os == NULL)
2437               {
2438                 bool static_or_reloc = (parameters->doing_static_link() ||
2439                                         parameters->options().relocatable());
2440                 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2441
2442                 *pstatus = CFVS_NO_OUTPUT_SECTION;
2443                 return 0;
2444               }
2445
2446             if (secoff64 == -1ULL)
2447               {
2448                 // The section needs special handling (e.g., a merge section).
2449
2450                 value = os->output_address(relobj, shndx, sym->value());
2451               }
2452             else
2453               {
2454                 Value_type secoff =
2455                   convert_types<Value_type, uint64_t>(secoff64);
2456                 if (sym->type() == elfcpp::STT_TLS)
2457                   value = sym->value() + os->tls_offset() + secoff;
2458                 else
2459                   value = sym->value() + os->address() + secoff;
2460               }
2461           }
2462       }
2463       break;
2464
2465     case Symbol::IN_OUTPUT_DATA:
2466       {
2467         Output_data* od = sym->output_data();
2468         value = sym->value();
2469         if (sym->type() != elfcpp::STT_TLS)
2470           value += od->address();
2471         else
2472           {
2473             Output_section* os = od->output_section();
2474             gold_assert(os != NULL);
2475             value += os->tls_offset() + (od->address() - os->address());
2476           }
2477         if (sym->offset_is_from_end())
2478           value += od->data_size();
2479       }
2480       break;
2481
2482     case Symbol::IN_OUTPUT_SEGMENT:
2483       {
2484         Output_segment* os = sym->output_segment();
2485         value = sym->value();
2486         if (sym->type() != elfcpp::STT_TLS)
2487           value += os->vaddr();
2488         switch (sym->offset_base())
2489           {
2490           case Symbol::SEGMENT_START:
2491             break;
2492           case Symbol::SEGMENT_END:
2493             value += os->memsz();
2494             break;
2495           case Symbol::SEGMENT_BSS:
2496             value += os->filesz();
2497             break;
2498           default:
2499             gold_unreachable();
2500           }
2501       }
2502       break;
2503
2504     case Symbol::IS_CONSTANT:
2505       value = sym->value();
2506       break;
2507
2508     case Symbol::IS_UNDEFINED:
2509       value = 0;
2510       break;
2511
2512     default:
2513       gold_unreachable();
2514     }
2515
2516   *pstatus = CFVS_OK;
2517   return value;
2518 }
2519
2520 // Finalize the symbol SYM.  This returns true if the symbol should be
2521 // added to the symbol table, false otherwise.
2522
2523 template<int size>
2524 bool
2525 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2526 {
2527   typedef typename Sized_symbol<size>::Value_type Value_type;
2528
2529   Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2530
2531   // The default version of a symbol may appear twice in the symbol
2532   // table.  We only need to finalize it once.
2533   if (sym->has_symtab_index())
2534     return false;
2535
2536   if (!sym->in_reg())
2537     {
2538       gold_assert(!sym->has_symtab_index());
2539       sym->set_symtab_index(-1U);
2540       gold_assert(sym->dynsym_index() == -1U);
2541       return false;
2542     }
2543
2544   // Compute final symbol value.
2545   Compute_final_value_status status;
2546   Value_type value = this->compute_final_value(sym, &status);
2547
2548   switch (status)
2549     {
2550     case CFVS_OK:
2551       break;
2552     case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2553       {
2554         bool is_ordinary;
2555         unsigned int shndx = sym->shndx(&is_ordinary);
2556         gold_error(_("%s: unsupported symbol section 0x%x"),
2557                    sym->demangled_name().c_str(), shndx);
2558       }
2559       break;
2560     case CFVS_NO_OUTPUT_SECTION:
2561       sym->set_symtab_index(-1U);
2562       return false;
2563     default:
2564       gold_unreachable();
2565     }
2566
2567   sym->set_value(value);
2568
2569   if (parameters->options().strip_all()
2570       || !parameters->options().should_retain_symbol(sym->name()))
2571     {
2572       sym->set_symtab_index(-1U);
2573       return false;
2574     }
2575
2576   return true;
2577 }
2578
2579 // Write out the global symbols.
2580
2581 void
2582 Symbol_table::write_globals(const Stringpool* sympool,
2583                             const Stringpool* dynpool,
2584                             Output_symtab_xindex* symtab_xindex,
2585                             Output_symtab_xindex* dynsym_xindex,
2586                             Output_file* of) const
2587 {
2588   switch (parameters->size_and_endianness())
2589     {
2590 #ifdef HAVE_TARGET_32_LITTLE
2591     case Parameters::TARGET_32_LITTLE:
2592       this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2593                                            dynsym_xindex, of);
2594       break;
2595 #endif
2596 #ifdef HAVE_TARGET_32_BIG
2597     case Parameters::TARGET_32_BIG:
2598       this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2599                                           dynsym_xindex, of);
2600       break;
2601 #endif
2602 #ifdef HAVE_TARGET_64_LITTLE
2603     case Parameters::TARGET_64_LITTLE:
2604       this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2605                                            dynsym_xindex, of);
2606       break;
2607 #endif
2608 #ifdef HAVE_TARGET_64_BIG
2609     case Parameters::TARGET_64_BIG:
2610       this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2611                                           dynsym_xindex, of);
2612       break;
2613 #endif
2614     default:
2615       gold_unreachable();
2616     }
2617 }
2618
2619 // Write out the global symbols.
2620
2621 template<int size, bool big_endian>
2622 void
2623 Symbol_table::sized_write_globals(const Stringpool* sympool,
2624                                   const Stringpool* dynpool,
2625                                   Output_symtab_xindex* symtab_xindex,
2626                                   Output_symtab_xindex* dynsym_xindex,
2627                                   Output_file* of) const
2628 {
2629   const Target& target = parameters->target();
2630
2631   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2632
2633   const unsigned int output_count = this->output_count_;
2634   const section_size_type oview_size = output_count * sym_size;
2635   const unsigned int first_global_index = this->first_global_index_;
2636   unsigned char* psyms;
2637   if (this->offset_ == 0 || output_count == 0)
2638     psyms = NULL;
2639   else
2640     psyms = of->get_output_view(this->offset_, oview_size);
2641
2642   const unsigned int dynamic_count = this->dynamic_count_;
2643   const section_size_type dynamic_size = dynamic_count * sym_size;
2644   const unsigned int first_dynamic_global_index =
2645     this->first_dynamic_global_index_;
2646   unsigned char* dynamic_view;
2647   if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2648     dynamic_view = NULL;
2649   else
2650     dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2651
2652   for (Symbol_table_type::const_iterator p = this->table_.begin();
2653        p != this->table_.end();
2654        ++p)
2655     {
2656       Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2657
2658       // Possibly warn about unresolved symbols in shared libraries.
2659       this->warn_about_undefined_dynobj_symbol(sym);
2660
2661       unsigned int sym_index = sym->symtab_index();
2662       unsigned int dynsym_index;
2663       if (dynamic_view == NULL)
2664         dynsym_index = -1U;
2665       else
2666         dynsym_index = sym->dynsym_index();
2667
2668       if (sym_index == -1U && dynsym_index == -1U)
2669         {
2670           // This symbol is not included in the output file.
2671           continue;
2672         }
2673
2674       unsigned int shndx;
2675       typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2676       typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2677       switch (sym->source())
2678         {
2679         case Symbol::FROM_OBJECT:
2680           {
2681             bool is_ordinary;
2682             unsigned int in_shndx = sym->shndx(&is_ordinary);
2683
2684             if (!is_ordinary
2685                 && in_shndx != elfcpp::SHN_ABS
2686                 && !Symbol::is_common_shndx(in_shndx))
2687               {
2688                 gold_error(_("%s: unsupported symbol section 0x%x"),
2689                            sym->demangled_name().c_str(), in_shndx);
2690                 shndx = in_shndx;
2691               }
2692             else
2693               {
2694                 Object* symobj = sym->object();
2695                 if (symobj->is_dynamic())
2696                   {
2697                     if (sym->needs_dynsym_value())
2698                       dynsym_value = target.dynsym_value(sym);
2699                     shndx = elfcpp::SHN_UNDEF;
2700                   }
2701                 else if (symobj->pluginobj() != NULL)
2702                   shndx = elfcpp::SHN_UNDEF;
2703                 else if (in_shndx == elfcpp::SHN_UNDEF
2704                          || (!is_ordinary
2705                              && (in_shndx == elfcpp::SHN_ABS
2706                                  || Symbol::is_common_shndx(in_shndx))))
2707                   shndx = in_shndx;
2708                 else
2709                   {
2710                     Relobj* relobj = static_cast<Relobj*>(symobj);
2711                     Output_section* os = relobj->output_section(in_shndx);
2712                     if (this->is_section_folded(relobj, in_shndx))
2713                       {
2714                         // This global symbol must be written out even though
2715                         // it is folded.
2716                         // Get the os of the section it is folded onto.
2717                         Section_id folded =
2718                              this->icf_->get_folded_section(relobj, in_shndx);
2719                         gold_assert(folded.first !=NULL);
2720                         Relobj* folded_obj = 
2721                           reinterpret_cast<Relobj*>(folded.first);
2722                         os = folded_obj->output_section(folded.second);  
2723                         gold_assert(os != NULL);
2724                       }
2725                     gold_assert(os != NULL);
2726                     shndx = os->out_shndx();
2727
2728                     if (shndx >= elfcpp::SHN_LORESERVE)
2729                       {
2730                         if (sym_index != -1U)
2731                           symtab_xindex->add(sym_index, shndx);
2732                         if (dynsym_index != -1U)
2733                           dynsym_xindex->add(dynsym_index, shndx);
2734                         shndx = elfcpp::SHN_XINDEX;
2735                       }
2736
2737                     // In object files symbol values are section
2738                     // relative.
2739                     if (parameters->options().relocatable())
2740                       sym_value -= os->address();
2741                   }
2742               }
2743           }
2744           break;
2745
2746         case Symbol::IN_OUTPUT_DATA:
2747           shndx = sym->output_data()->out_shndx();
2748           if (shndx >= elfcpp::SHN_LORESERVE)
2749             {
2750               if (sym_index != -1U)
2751                 symtab_xindex->add(sym_index, shndx);
2752               if (dynsym_index != -1U)
2753                 dynsym_xindex->add(dynsym_index, shndx);
2754               shndx = elfcpp::SHN_XINDEX;
2755             }
2756           break;
2757
2758         case Symbol::IN_OUTPUT_SEGMENT:
2759           shndx = elfcpp::SHN_ABS;
2760           break;
2761
2762         case Symbol::IS_CONSTANT:
2763           shndx = elfcpp::SHN_ABS;
2764           break;
2765
2766         case Symbol::IS_UNDEFINED:
2767           shndx = elfcpp::SHN_UNDEF;
2768           break;
2769
2770         default:
2771           gold_unreachable();
2772         }
2773
2774       if (sym_index != -1U)
2775         {
2776           sym_index -= first_global_index;
2777           gold_assert(sym_index < output_count);
2778           unsigned char* ps = psyms + (sym_index * sym_size);
2779           this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2780                                                      sympool, ps);
2781         }
2782
2783       if (dynsym_index != -1U)
2784         {
2785           dynsym_index -= first_dynamic_global_index;
2786           gold_assert(dynsym_index < dynamic_count);
2787           unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2788           this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2789                                                      dynpool, pd);
2790         }
2791     }
2792
2793   of->write_output_view(this->offset_, oview_size, psyms);
2794   if (dynamic_view != NULL)
2795     of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2796 }
2797
2798 // Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2799 // strtab holding the name.
2800
2801 template<int size, bool big_endian>
2802 void
2803 Symbol_table::sized_write_symbol(
2804     Sized_symbol<size>* sym,
2805     typename elfcpp::Elf_types<size>::Elf_Addr value,
2806     unsigned int shndx,
2807     const Stringpool* pool,
2808     unsigned char* p) const
2809 {
2810   elfcpp::Sym_write<size, big_endian> osym(p);
2811   osym.put_st_name(pool->get_offset(sym->name()));
2812   osym.put_st_value(value);
2813   // Use a symbol size of zero for undefined symbols from shared libraries.
2814   if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2815     osym.put_st_size(0);
2816   else
2817     osym.put_st_size(sym->symsize());
2818   elfcpp::STT type = sym->type();
2819   // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2820   if (type == elfcpp::STT_GNU_IFUNC
2821       && sym->is_from_dynobj())
2822     type = elfcpp::STT_FUNC;
2823   // A version script may have overridden the default binding.
2824   if (sym->is_forced_local())
2825     osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2826   else
2827     osym.put_st_info(elfcpp::elf_st_info(sym->binding(), type));
2828   osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2829   osym.put_st_shndx(shndx);
2830 }
2831
2832 // Check for unresolved symbols in shared libraries.  This is
2833 // controlled by the --allow-shlib-undefined option.
2834
2835 // We only warn about libraries for which we have seen all the
2836 // DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2837 // which were not seen in this link.  If we didn't see a DT_NEEDED
2838 // entry, we aren't going to be able to reliably report whether the
2839 // symbol is undefined.
2840
2841 // We also don't warn about libraries found in a system library
2842 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2843 // are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2844 // can have undefined references satisfied by ld-linux.so.
2845
2846 inline void
2847 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2848 {
2849   bool dummy;
2850   if (sym->source() == Symbol::FROM_OBJECT
2851       && sym->object()->is_dynamic()
2852       && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2853       && sym->binding() != elfcpp::STB_WEAK
2854       && !parameters->options().allow_shlib_undefined()
2855       && !parameters->target().is_defined_by_abi(sym)
2856       && !sym->object()->is_in_system_directory())
2857     {
2858       // A very ugly cast.
2859       Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2860       if (!dynobj->has_unknown_needed_entries())
2861         gold_undefined_symbol(sym);
2862     }
2863 }
2864
2865 // Write out a section symbol.  Return the update offset.
2866
2867 void
2868 Symbol_table::write_section_symbol(const Output_section *os,
2869                                    Output_symtab_xindex* symtab_xindex,
2870                                    Output_file* of,
2871                                    off_t offset) const
2872 {
2873   switch (parameters->size_and_endianness())
2874     {
2875 #ifdef HAVE_TARGET_32_LITTLE
2876     case Parameters::TARGET_32_LITTLE:
2877       this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2878                                                   offset);
2879       break;
2880 #endif
2881 #ifdef HAVE_TARGET_32_BIG
2882     case Parameters::TARGET_32_BIG:
2883       this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2884                                                  offset);
2885       break;
2886 #endif
2887 #ifdef HAVE_TARGET_64_LITTLE
2888     case Parameters::TARGET_64_LITTLE:
2889       this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2890                                                   offset);
2891       break;
2892 #endif
2893 #ifdef HAVE_TARGET_64_BIG
2894     case Parameters::TARGET_64_BIG:
2895       this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2896                                                  offset);
2897       break;
2898 #endif
2899     default:
2900       gold_unreachable();
2901     }
2902 }
2903
2904 // Write out a section symbol, specialized for size and endianness.
2905
2906 template<int size, bool big_endian>
2907 void
2908 Symbol_table::sized_write_section_symbol(const Output_section* os,
2909                                          Output_symtab_xindex* symtab_xindex,
2910                                          Output_file* of,
2911                                          off_t offset) const
2912 {
2913   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2914
2915   unsigned char* pov = of->get_output_view(offset, sym_size);
2916
2917   elfcpp::Sym_write<size, big_endian> osym(pov);
2918   osym.put_st_name(0);
2919   if (parameters->options().relocatable())
2920     osym.put_st_value(0);
2921   else
2922     osym.put_st_value(os->address());
2923   osym.put_st_size(0);
2924   osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2925                                        elfcpp::STT_SECTION));
2926   osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2927
2928   unsigned int shndx = os->out_shndx();
2929   if (shndx >= elfcpp::SHN_LORESERVE)
2930     {
2931       symtab_xindex->add(os->symtab_index(), shndx);
2932       shndx = elfcpp::SHN_XINDEX;
2933     }
2934   osym.put_st_shndx(shndx);
2935
2936   of->write_output_view(offset, sym_size, pov);
2937 }
2938
2939 // Print statistical information to stderr.  This is used for --stats.
2940
2941 void
2942 Symbol_table::print_stats() const
2943 {
2944 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2945   fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2946           program_name, this->table_.size(), this->table_.bucket_count());
2947 #else
2948   fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2949           program_name, this->table_.size());
2950 #endif
2951   this->namepool_.print_stats("symbol table stringpool");
2952 }
2953
2954 // We check for ODR violations by looking for symbols with the same
2955 // name for which the debugging information reports that they were
2956 // defined in different source locations.  When comparing the source
2957 // location, we consider instances with the same base filename and
2958 // line number to be the same.  This is because different object
2959 // files/shared libraries can include the same header file using
2960 // different paths, and we don't want to report an ODR violation in
2961 // that case.
2962
2963 // This struct is used to compare line information, as returned by
2964 // Dwarf_line_info::one_addr2line.  It implements a < comparison
2965 // operator used with std::set.
2966
2967 struct Odr_violation_compare
2968 {
2969   bool
2970   operator()(const std::string& s1, const std::string& s2) const
2971   {
2972     std::string::size_type pos1 = s1.rfind('/');
2973     std::string::size_type pos2 = s2.rfind('/');
2974     if (pos1 == std::string::npos
2975         || pos2 == std::string::npos)
2976       return s1 < s2;
2977     return s1.compare(pos1, std::string::npos,
2978                       s2, pos2, std::string::npos) < 0;
2979   }
2980 };
2981
2982 // Check candidate_odr_violations_ to find symbols with the same name
2983 // but apparently different definitions (different source-file/line-no).
2984
2985 void
2986 Symbol_table::detect_odr_violations(const Task* task,
2987                                     const char* output_file_name) const
2988 {
2989   for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2990        it != candidate_odr_violations_.end();
2991        ++it)
2992     {
2993       const char* symbol_name = it->first;
2994       // We use a sorted set so the output is deterministic.
2995       std::set<std::string, Odr_violation_compare> line_nums;
2996
2997       for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
2998                locs = it->second.begin();
2999            locs != it->second.end();
3000            ++locs)
3001         {
3002           // We need to lock the object in order to read it.  This
3003           // means that we have to run in a singleton Task.  If we
3004           // want to run this in a general Task for better
3005           // performance, we will need one Task for object, plus
3006           // appropriate locking to ensure that we don't conflict with
3007           // other uses of the object.  Also note, one_addr2line is not
3008           // currently thread-safe.
3009           Task_lock_obj<Object> tl(task, locs->object);
3010           // 16 is the size of the object-cache that one_addr2line should use.
3011           std::string lineno = Dwarf_line_info::one_addr2line(
3012               locs->object, locs->shndx, locs->offset, 16);
3013           if (!lineno.empty())
3014             line_nums.insert(lineno);
3015         }
3016
3017       if (line_nums.size() > 1)
3018         {
3019           gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3020                          "places (possible ODR violation):"),
3021                        output_file_name, demangle(symbol_name).c_str());
3022           for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3023                it2 != line_nums.end();
3024                ++it2)
3025             fprintf(stderr, "  %s\n", it2->c_str());
3026         }
3027     }
3028   // We only call one_addr2line() in this function, so we can clear its cache.
3029   Dwarf_line_info::clear_addr2line_cache();
3030 }
3031
3032 // Warnings functions.
3033
3034 // Add a new warning.
3035
3036 void
3037 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3038                       const std::string& warning)
3039 {
3040   name = symtab->canonicalize_name(name);
3041   this->warnings_[name].set(obj, warning);
3042 }
3043
3044 // Look through the warnings and mark the symbols for which we should
3045 // warn.  This is called during Layout::finalize when we know the
3046 // sources for all the symbols.
3047
3048 void
3049 Warnings::note_warnings(Symbol_table* symtab)
3050 {
3051   for (Warning_table::iterator p = this->warnings_.begin();
3052        p != this->warnings_.end();
3053        ++p)
3054     {
3055       Symbol* sym = symtab->lookup(p->first, NULL);
3056       if (sym != NULL
3057           && sym->source() == Symbol::FROM_OBJECT
3058           && sym->object() == p->second.object)
3059         sym->set_has_warning();
3060     }
3061 }
3062
3063 // Issue a warning.  This is called when we see a relocation against a
3064 // symbol for which has a warning.
3065
3066 template<int size, bool big_endian>
3067 void
3068 Warnings::issue_warning(const Symbol* sym,
3069                         const Relocate_info<size, big_endian>* relinfo,
3070                         size_t relnum, off_t reloffset) const
3071 {
3072   gold_assert(sym->has_warning());
3073   Warning_table::const_iterator p = this->warnings_.find(sym->name());
3074   gold_assert(p != this->warnings_.end());
3075   gold_warning_at_location(relinfo, relnum, reloffset,
3076                            "%s", p->second.text.c_str());
3077 }
3078
3079 // Instantiate the templates we need.  We could use the configure
3080 // script to restrict this to only the ones needed for implemented
3081 // targets.
3082
3083 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3084 template
3085 void
3086 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3087 #endif
3088
3089 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3090 template
3091 void
3092 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3093 #endif
3094
3095 #ifdef HAVE_TARGET_32_LITTLE
3096 template
3097 void
3098 Symbol_table::add_from_relobj<32, false>(
3099     Sized_relobj<32, false>* relobj,
3100     const unsigned char* syms,
3101     size_t count,
3102     size_t symndx_offset,
3103     const char* sym_names,
3104     size_t sym_name_size,
3105     Sized_relobj<32, false>::Symbols* sympointers,
3106     size_t* defined);
3107 #endif
3108
3109 #ifdef HAVE_TARGET_32_BIG
3110 template
3111 void
3112 Symbol_table::add_from_relobj<32, true>(
3113     Sized_relobj<32, true>* relobj,
3114     const unsigned char* syms,
3115     size_t count,
3116     size_t symndx_offset,
3117     const char* sym_names,
3118     size_t sym_name_size,
3119     Sized_relobj<32, true>::Symbols* sympointers,
3120     size_t* defined);
3121 #endif
3122
3123 #ifdef HAVE_TARGET_64_LITTLE
3124 template
3125 void
3126 Symbol_table::add_from_relobj<64, false>(
3127     Sized_relobj<64, false>* relobj,
3128     const unsigned char* syms,
3129     size_t count,
3130     size_t symndx_offset,
3131     const char* sym_names,
3132     size_t sym_name_size,
3133     Sized_relobj<64, false>::Symbols* sympointers,
3134     size_t* defined);
3135 #endif
3136
3137 #ifdef HAVE_TARGET_64_BIG
3138 template
3139 void
3140 Symbol_table::add_from_relobj<64, true>(
3141     Sized_relobj<64, true>* relobj,
3142     const unsigned char* syms,
3143     size_t count,
3144     size_t symndx_offset,
3145     const char* sym_names,
3146     size_t sym_name_size,
3147     Sized_relobj<64, true>::Symbols* sympointers,
3148     size_t* defined);
3149 #endif
3150
3151 #ifdef HAVE_TARGET_32_LITTLE
3152 template
3153 Symbol*
3154 Symbol_table::add_from_pluginobj<32, false>(
3155     Sized_pluginobj<32, false>* obj,
3156     const char* name,
3157     const char* ver,
3158     elfcpp::Sym<32, false>* sym);
3159 #endif
3160
3161 #ifdef HAVE_TARGET_32_BIG
3162 template
3163 Symbol*
3164 Symbol_table::add_from_pluginobj<32, true>(
3165     Sized_pluginobj<32, true>* obj,
3166     const char* name,
3167     const char* ver,
3168     elfcpp::Sym<32, true>* sym);
3169 #endif
3170
3171 #ifdef HAVE_TARGET_64_LITTLE
3172 template
3173 Symbol*
3174 Symbol_table::add_from_pluginobj<64, false>(
3175     Sized_pluginobj<64, false>* obj,
3176     const char* name,
3177     const char* ver,
3178     elfcpp::Sym<64, false>* sym);
3179 #endif
3180
3181 #ifdef HAVE_TARGET_64_BIG
3182 template
3183 Symbol*
3184 Symbol_table::add_from_pluginobj<64, true>(
3185     Sized_pluginobj<64, true>* obj,
3186     const char* name,
3187     const char* ver,
3188     elfcpp::Sym<64, true>* sym);
3189 #endif
3190
3191 #ifdef HAVE_TARGET_32_LITTLE
3192 template
3193 void
3194 Symbol_table::add_from_dynobj<32, false>(
3195     Sized_dynobj<32, false>* dynobj,
3196     const unsigned char* syms,
3197     size_t count,
3198     const char* sym_names,
3199     size_t sym_name_size,
3200     const unsigned char* versym,
3201     size_t versym_size,
3202     const std::vector<const char*>* version_map,
3203     Sized_relobj<32, false>::Symbols* sympointers,
3204     size_t* defined);
3205 #endif
3206
3207 #ifdef HAVE_TARGET_32_BIG
3208 template
3209 void
3210 Symbol_table::add_from_dynobj<32, true>(
3211     Sized_dynobj<32, true>* dynobj,
3212     const unsigned char* syms,
3213     size_t count,
3214     const char* sym_names,
3215     size_t sym_name_size,
3216     const unsigned char* versym,
3217     size_t versym_size,
3218     const std::vector<const char*>* version_map,
3219     Sized_relobj<32, true>::Symbols* sympointers,
3220     size_t* defined);
3221 #endif
3222
3223 #ifdef HAVE_TARGET_64_LITTLE
3224 template
3225 void
3226 Symbol_table::add_from_dynobj<64, false>(
3227     Sized_dynobj<64, false>* dynobj,
3228     const unsigned char* syms,
3229     size_t count,
3230     const char* sym_names,
3231     size_t sym_name_size,
3232     const unsigned char* versym,
3233     size_t versym_size,
3234     const std::vector<const char*>* version_map,
3235     Sized_relobj<64, false>::Symbols* sympointers,
3236     size_t* defined);
3237 #endif
3238
3239 #ifdef HAVE_TARGET_64_BIG
3240 template
3241 void
3242 Symbol_table::add_from_dynobj<64, true>(
3243     Sized_dynobj<64, true>* dynobj,
3244     const unsigned char* syms,
3245     size_t count,
3246     const char* sym_names,
3247     size_t sym_name_size,
3248     const unsigned char* versym,
3249     size_t versym_size,
3250     const std::vector<const char*>* version_map,
3251     Sized_relobj<64, true>::Symbols* sympointers,
3252     size_t* defined);
3253 #endif
3254
3255 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3256 template
3257 void
3258 Symbol_table::define_with_copy_reloc<32>(
3259     Sized_symbol<32>* sym,
3260     Output_data* posd,
3261     elfcpp::Elf_types<32>::Elf_Addr value);
3262 #endif
3263
3264 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3265 template
3266 void
3267 Symbol_table::define_with_copy_reloc<64>(
3268     Sized_symbol<64>* sym,
3269     Output_data* posd,
3270     elfcpp::Elf_types<64>::Elf_Addr value);
3271 #endif
3272
3273 #ifdef HAVE_TARGET_32_LITTLE
3274 template
3275 void
3276 Warnings::issue_warning<32, false>(const Symbol* sym,
3277                                    const Relocate_info<32, false>* relinfo,
3278                                    size_t relnum, off_t reloffset) const;
3279 #endif
3280
3281 #ifdef HAVE_TARGET_32_BIG
3282 template
3283 void
3284 Warnings::issue_warning<32, true>(const Symbol* sym,
3285                                   const Relocate_info<32, true>* relinfo,
3286                                   size_t relnum, off_t reloffset) const;
3287 #endif
3288
3289 #ifdef HAVE_TARGET_64_LITTLE
3290 template
3291 void
3292 Warnings::issue_warning<64, false>(const Symbol* sym,
3293                                    const Relocate_info<64, false>* relinfo,
3294                                    size_t relnum, off_t reloffset) const;
3295 #endif
3296
3297 #ifdef HAVE_TARGET_64_BIG
3298 template
3299 void
3300 Warnings::issue_warning<64, true>(const Symbol* sym,
3301                                   const Relocate_info<64, true>* relinfo,
3302                                   size_t relnum, off_t reloffset) const;
3303 #endif
3304
3305 } // End namespace gold.