1// symtab.cc -- the gold symbol table
2
3// Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 "script.h"
42#include "plugin.h"
43
44namespace gold
45{
46
47// Class Symbol.
48
49// Initialize fields in Symbol.  This initializes everything except u_
50// and source_.
51
52void
53Symbol::init_fields(const char* name, const char* version,
54		    elfcpp::STT type, elfcpp::STB binding,
55		    elfcpp::STV visibility, unsigned char nonvis)
56{
57  this->name_ = name;
58  this->version_ = version;
59  this->symtab_index_ = 0;
60  this->dynsym_index_ = 0;
61  this->got_offsets_.init();
62  this->plt_offset_ = -1U;
63  this->type_ = type;
64  this->binding_ = binding;
65  this->visibility_ = visibility;
66  this->nonvis_ = nonvis;
67  this->is_def_ = false;
68  this->is_forwarder_ = false;
69  this->has_alias_ = false;
70  this->needs_dynsym_entry_ = false;
71  this->in_reg_ = false;
72  this->in_dyn_ = false;
73  this->has_warning_ = false;
74  this->is_copied_from_dynobj_ = false;
75  this->is_forced_local_ = false;
76  this->is_ordinary_shndx_ = false;
77  this->in_real_elf_ = false;
78  this->is_defined_in_discarded_section_ = false;
79  this->undef_binding_set_ = false;
80  this->undef_binding_weak_ = false;
81}
82
83// Return the demangled version of the symbol's name, but only
84// if the --demangle flag was set.
85
86static std::string
87demangle(const char* name)
88{
89  if (!parameters->options().do_demangle())
90    return name;
91
92  // cplus_demangle allocates memory for the result it returns,
93  // and returns NULL if the name is already demangled.
94  char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
95  if (demangled_name == NULL)
96    return name;
97
98  std::string retval(demangled_name);
99  free(demangled_name);
100  return retval;
101}
102
103std::string
104Symbol::demangled_name() const
105{
106  return demangle(this->name());
107}
108
109// Initialize the fields in the base class Symbol for SYM in OBJECT.
110
111template<int size, bool big_endian>
112void
113Symbol::init_base_object(const char* name, const char* version, Object* object,
114			 const elfcpp::Sym<size, big_endian>& sym,
115			 unsigned int st_shndx, bool is_ordinary)
116{
117  this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
118		    sym.get_st_visibility(), sym.get_st_nonvis());
119  this->u_.from_object.object = object;
120  this->u_.from_object.shndx = st_shndx;
121  this->is_ordinary_shndx_ = is_ordinary;
122  this->source_ = FROM_OBJECT;
123  this->in_reg_ = !object->is_dynamic();
124  this->in_dyn_ = object->is_dynamic();
125  this->in_real_elf_ = object->pluginobj() == NULL;
126}
127
128// Initialize the fields in the base class Symbol for a symbol defined
129// in an Output_data.
130
131void
132Symbol::init_base_output_data(const char* name, const char* version,
133			      Output_data* od, elfcpp::STT type,
134			      elfcpp::STB binding, elfcpp::STV visibility,
135			      unsigned char nonvis, bool offset_is_from_end)
136{
137  this->init_fields(name, version, type, binding, visibility, nonvis);
138  this->u_.in_output_data.output_data = od;
139  this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
140  this->source_ = IN_OUTPUT_DATA;
141  this->in_reg_ = true;
142  this->in_real_elf_ = true;
143}
144
145// Initialize the fields in the base class Symbol for a symbol defined
146// in an Output_segment.
147
148void
149Symbol::init_base_output_segment(const char* name, const char* version,
150				 Output_segment* os, elfcpp::STT type,
151				 elfcpp::STB binding, elfcpp::STV visibility,
152				 unsigned char nonvis,
153				 Segment_offset_base offset_base)
154{
155  this->init_fields(name, version, type, binding, visibility, nonvis);
156  this->u_.in_output_segment.output_segment = os;
157  this->u_.in_output_segment.offset_base = offset_base;
158  this->source_ = IN_OUTPUT_SEGMENT;
159  this->in_reg_ = true;
160  this->in_real_elf_ = true;
161}
162
163// Initialize the fields in the base class Symbol for a symbol defined
164// as a constant.
165
166void
167Symbol::init_base_constant(const char* name, const char* version,
168			   elfcpp::STT type, elfcpp::STB binding,
169			   elfcpp::STV visibility, unsigned char nonvis)
170{
171  this->init_fields(name, version, type, binding, visibility, nonvis);
172  this->source_ = IS_CONSTANT;
173  this->in_reg_ = true;
174  this->in_real_elf_ = true;
175}
176
177// Initialize the fields in the base class Symbol for an undefined
178// symbol.
179
180void
181Symbol::init_base_undefined(const char* name, const char* version,
182			    elfcpp::STT type, elfcpp::STB binding,
183			    elfcpp::STV visibility, unsigned char nonvis)
184{
185  this->init_fields(name, version, type, binding, visibility, nonvis);
186  this->dynsym_index_ = -1U;
187  this->source_ = IS_UNDEFINED;
188  this->in_reg_ = true;
189  this->in_real_elf_ = true;
190}
191
192// Allocate a common symbol in the base.
193
194void
195Symbol::allocate_base_common(Output_data* od)
196{
197  gold_assert(this->is_common());
198  this->source_ = IN_OUTPUT_DATA;
199  this->u_.in_output_data.output_data = od;
200  this->u_.in_output_data.offset_is_from_end = false;
201}
202
203// Initialize the fields in Sized_symbol for SYM in OBJECT.
204
205template<int size>
206template<bool big_endian>
207void
208Sized_symbol<size>::init_object(const char* name, const char* version,
209				Object* object,
210				const elfcpp::Sym<size, big_endian>& sym,
211				unsigned int st_shndx, bool is_ordinary)
212{
213  this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
214  this->value_ = sym.get_st_value();
215  this->symsize_ = sym.get_st_size();
216}
217
218// Initialize the fields in Sized_symbol for a symbol defined in an
219// Output_data.
220
221template<int size>
222void
223Sized_symbol<size>::init_output_data(const char* name, const char* version,
224				     Output_data* od, Value_type value,
225				     Size_type symsize, elfcpp::STT type,
226				     elfcpp::STB binding,
227				     elfcpp::STV visibility,
228				     unsigned char nonvis,
229				     bool offset_is_from_end)
230{
231  this->init_base_output_data(name, version, od, type, binding, visibility,
232			      nonvis, offset_is_from_end);
233  this->value_ = value;
234  this->symsize_ = symsize;
235}
236
237// Initialize the fields in Sized_symbol for a symbol defined in an
238// Output_segment.
239
240template<int size>
241void
242Sized_symbol<size>::init_output_segment(const char* name, const char* version,
243					Output_segment* os, Value_type value,
244					Size_type symsize, elfcpp::STT type,
245					elfcpp::STB binding,
246					elfcpp::STV visibility,
247					unsigned char nonvis,
248					Segment_offset_base offset_base)
249{
250  this->init_base_output_segment(name, version, os, type, binding, visibility,
251				 nonvis, offset_base);
252  this->value_ = value;
253  this->symsize_ = symsize;
254}
255
256// Initialize the fields in Sized_symbol for a symbol defined as a
257// constant.
258
259template<int size>
260void
261Sized_symbol<size>::init_constant(const char* name, const char* version,
262				  Value_type value, Size_type symsize,
263				  elfcpp::STT type, elfcpp::STB binding,
264				  elfcpp::STV visibility, unsigned char nonvis)
265{
266  this->init_base_constant(name, version, type, binding, visibility, nonvis);
267  this->value_ = value;
268  this->symsize_ = symsize;
269}
270
271// Initialize the fields in Sized_symbol for an undefined symbol.
272
273template<int size>
274void
275Sized_symbol<size>::init_undefined(const char* name, const char* version,
276				   elfcpp::STT type, elfcpp::STB binding,
277				   elfcpp::STV visibility, unsigned char nonvis)
278{
279  this->init_base_undefined(name, version, type, binding, visibility, nonvis);
280  this->value_ = 0;
281  this->symsize_ = 0;
282}
283
284// Return true if SHNDX represents a common symbol.
285
286bool
287Symbol::is_common_shndx(unsigned int shndx)
288{
289  return (shndx == elfcpp::SHN_COMMON
290	  || shndx == parameters->target().small_common_shndx()
291	  || shndx == parameters->target().large_common_shndx());
292}
293
294// Allocate a common symbol.
295
296template<int size>
297void
298Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
299{
300  this->allocate_base_common(od);
301  this->value_ = value;
302}
303
304// The ""'s around str ensure str is a string literal, so sizeof works.
305#define strprefix(var, str)   (strncmp(var, str, sizeof("" str "") - 1) == 0)
306
307// Return true if this symbol should be added to the dynamic symbol
308// table.
309
310inline bool
311Symbol::should_add_dynsym_entry(Symbol_table* symtab) const
312{
313  // If the symbol is used by a dynamic relocation, we need to add it.
314  if (this->needs_dynsym_entry())
315    return true;
316
317  // If this symbol's section is not added, the symbol need not be added.
318  // The section may have been GCed.  Note that export_dynamic is being
319  // overridden here.  This should not be done for shared objects.
320  if (parameters->options().gc_sections()
321      && !parameters->options().shared()
322      && this->source() == Symbol::FROM_OBJECT
323      && !this->object()->is_dynamic())
324    {
325      Relobj* relobj = static_cast<Relobj*>(this->object());
326      bool is_ordinary;
327      unsigned int shndx = this->shndx(&is_ordinary);
328      if (is_ordinary && shndx != elfcpp::SHN_UNDEF
329          && !relobj->is_section_included(shndx)
330          && !symtab->is_section_folded(relobj, shndx))
331        return false;
332    }
333
334  // If the symbol was forced local in a version script, do not add it.
335  if (this->is_forced_local())
336    return false;
337
338  // If the symbol was forced dynamic in a --dynamic-list file, add it.
339  if (parameters->options().in_dynamic_list(this->name()))
340    return true;
341
342  // If dynamic-list-data was specified, add any STT_OBJECT.
343  if (parameters->options().dynamic_list_data()
344      && !this->is_from_dynobj()
345      && this->type() == elfcpp::STT_OBJECT)
346    return true;
347
348  // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
349  // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
350  if ((parameters->options().dynamic_list_cpp_new()
351       || parameters->options().dynamic_list_cpp_typeinfo())
352      && !this->is_from_dynobj())
353    {
354      // TODO(csilvers): We could probably figure out if we're an operator
355      //                 new/delete or typeinfo without the need to demangle.
356      char* demangled_name = cplus_demangle(this->name(),
357                                            DMGL_ANSI | DMGL_PARAMS);
358      if (demangled_name == NULL)
359        {
360          // Not a C++ symbol, so it can't satisfy these flags
361        }
362      else if (parameters->options().dynamic_list_cpp_new()
363               && (strprefix(demangled_name, "operator new")
364                   || strprefix(demangled_name, "operator delete")))
365        {
366          free(demangled_name);
367          return true;
368        }
369      else if (parameters->options().dynamic_list_cpp_typeinfo()
370               && (strprefix(demangled_name, "typeinfo name for")
371                   || strprefix(demangled_name, "typeinfo for")))
372        {
373          free(demangled_name);
374          return true;
375        }
376      else
377        free(demangled_name);
378    }
379
380  // If exporting all symbols or building a shared library,
381  // and the symbol is defined in a regular object and is
382  // externally visible, we need to add it.
383  if ((parameters->options().export_dynamic() || parameters->options().shared())
384      && !this->is_from_dynobj()
385      && this->is_externally_visible())
386    return true;
387
388  return false;
389}
390
391// Return true if the final value of this symbol is known at link
392// time.
393
394bool
395Symbol::final_value_is_known() const
396{
397  // If we are not generating an executable, then no final values are
398  // known, since they will change at runtime.
399  if (parameters->options().output_is_position_independent()
400      || parameters->options().relocatable())
401    return false;
402
403  // If the symbol is not from an object file, and is not undefined,
404  // then it is defined, and known.
405  if (this->source_ != FROM_OBJECT)
406    {
407      if (this->source_ != IS_UNDEFINED)
408	return true;
409    }
410  else
411    {
412      // If the symbol is from a dynamic object, then the final value
413      // is not known.
414      if (this->object()->is_dynamic())
415	return false;
416
417      // If the symbol is not undefined (it is defined or common),
418      // then the final value is known.
419      if (!this->is_undefined())
420	return true;
421    }
422
423  // If the symbol is undefined, then whether the final value is known
424  // depends on whether we are doing a static link.  If we are doing a
425  // dynamic link, then the final value could be filled in at runtime.
426  // This could reasonably be the case for a weak undefined symbol.
427  return parameters->doing_static_link();
428}
429
430// Return the output section where this symbol is defined.
431
432Output_section*
433Symbol::output_section() const
434{
435  switch (this->source_)
436    {
437    case FROM_OBJECT:
438      {
439	unsigned int shndx = this->u_.from_object.shndx;
440	if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
441	  {
442	    gold_assert(!this->u_.from_object.object->is_dynamic());
443	    gold_assert(this->u_.from_object.object->pluginobj() == NULL);
444	    Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
445	    return relobj->output_section(shndx);
446	  }
447	return NULL;
448      }
449
450    case IN_OUTPUT_DATA:
451      return this->u_.in_output_data.output_data->output_section();
452
453    case IN_OUTPUT_SEGMENT:
454    case IS_CONSTANT:
455    case IS_UNDEFINED:
456      return NULL;
457
458    default:
459      gold_unreachable();
460    }
461}
462
463// Set the symbol's output section.  This is used for symbols defined
464// in scripts.  This should only be called after the symbol table has
465// been finalized.
466
467void
468Symbol::set_output_section(Output_section* os)
469{
470  switch (this->source_)
471    {
472    case FROM_OBJECT:
473    case IN_OUTPUT_DATA:
474      gold_assert(this->output_section() == os);
475      break;
476    case IS_CONSTANT:
477      this->source_ = IN_OUTPUT_DATA;
478      this->u_.in_output_data.output_data = os;
479      this->u_.in_output_data.offset_is_from_end = false;
480      break;
481    case IN_OUTPUT_SEGMENT:
482    case IS_UNDEFINED:
483    default:
484      gold_unreachable();
485    }
486}
487
488// Class Symbol_table.
489
490Symbol_table::Symbol_table(unsigned int count,
491                           const Version_script_info& version_script)
492  : saw_undefined_(0), offset_(0), table_(count), namepool_(),
493    forwarders_(), commons_(), tls_commons_(), small_commons_(),
494    large_commons_(), forced_locals_(), warnings_(),
495    version_script_(version_script), gc_(NULL), icf_(NULL)
496{
497  namepool_.reserve(count);
498}
499
500Symbol_table::~Symbol_table()
501{
502}
503
504// The symbol table key equality function.  This is called with
505// Stringpool keys.
506
507inline bool
508Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
509					  const Symbol_table_key& k2) const
510{
511  return k1.first == k2.first && k1.second == k2.second;
512}
513
514bool
515Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
516{
517  return (parameters->options().icf_enabled()
518          && this->icf_->is_section_folded(obj, shndx));
519}
520
521// For symbols that have been listed with -u option, add them to the
522// work list to avoid gc'ing them.
523
524void
525Symbol_table::gc_mark_undef_symbols(Layout* layout)
526{
527  for (options::String_set::const_iterator p =
528	 parameters->options().undefined_begin();
529       p != parameters->options().undefined_end();
530       ++p)
531    {
532      const char* name = p->c_str();
533      Symbol* sym = this->lookup(name);
534      gold_assert(sym != NULL);
535      if (sym->source() == Symbol::FROM_OBJECT
536          && !sym->object()->is_dynamic())
537        {
538          Relobj* obj = static_cast<Relobj*>(sym->object());
539          bool is_ordinary;
540          unsigned int shndx = sym->shndx(&is_ordinary);
541          if (is_ordinary)
542            {
543              gold_assert(this->gc_ != NULL);
544              this->gc_->worklist().push(Section_id(obj, shndx));
545            }
546        }
547    }
548
549  for (Script_options::referenced_const_iterator p =
550	 layout->script_options()->referenced_begin();
551       p != layout->script_options()->referenced_end();
552       ++p)
553    {
554      Symbol* sym = this->lookup(p->c_str());
555      gold_assert(sym != NULL);
556      if (sym->source() == Symbol::FROM_OBJECT
557	  && !sym->object()->is_dynamic())
558	{
559	  Relobj* obj = static_cast<Relobj*>(sym->object());
560	  bool is_ordinary;
561	  unsigned int shndx = sym->shndx(&is_ordinary);
562	  if (is_ordinary)
563	    {
564	      gold_assert(this->gc_ != NULL);
565	      this->gc_->worklist().push(Section_id(obj, shndx));
566	    }
567	}
568    }
569}
570
571void
572Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
573{
574  if (!sym->is_from_dynobj()
575      && sym->is_externally_visible())
576    {
577      //Add the object and section to the work list.
578      Relobj* obj = static_cast<Relobj*>(sym->object());
579      bool is_ordinary;
580      unsigned int shndx = sym->shndx(&is_ordinary);
581      if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
582        {
583          gold_assert(this->gc_!= NULL);
584          this->gc_->worklist().push(Section_id(obj, shndx));
585        }
586    }
587}
588
589// When doing garbage collection, keep symbols that have been seen in
590// dynamic objects.
591inline void
592Symbol_table::gc_mark_dyn_syms(Symbol* sym)
593{
594  if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
595      && !sym->object()->is_dynamic())
596    {
597      Relobj* obj = static_cast<Relobj*>(sym->object());
598      bool is_ordinary;
599      unsigned int shndx = sym->shndx(&is_ordinary);
600      if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
601        {
602          gold_assert(this->gc_ != NULL);
603          this->gc_->worklist().push(Section_id(obj, shndx));
604        }
605    }
606}
607
608// Make TO a symbol which forwards to FROM.
609
610void
611Symbol_table::make_forwarder(Symbol* from, Symbol* to)
612{
613  gold_assert(from != to);
614  gold_assert(!from->is_forwarder() && !to->is_forwarder());
615  this->forwarders_[from] = to;
616  from->set_forwarder();
617}
618
619// Resolve the forwards from FROM, returning the real symbol.
620
621Symbol*
622Symbol_table::resolve_forwards(const Symbol* from) const
623{
624  gold_assert(from->is_forwarder());
625  Unordered_map<const Symbol*, Symbol*>::const_iterator p =
626    this->forwarders_.find(from);
627  gold_assert(p != this->forwarders_.end());
628  return p->second;
629}
630
631// Look up a symbol by name.
632
633Symbol*
634Symbol_table::lookup(const char* name, const char* version) const
635{
636  Stringpool::Key name_key;
637  name = this->namepool_.find(name, &name_key);
638  if (name == NULL)
639    return NULL;
640
641  Stringpool::Key version_key = 0;
642  if (version != NULL)
643    {
644      version = this->namepool_.find(version, &version_key);
645      if (version == NULL)
646	return NULL;
647    }
648
649  Symbol_table_key key(name_key, version_key);
650  Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
651  if (p == this->table_.end())
652    return NULL;
653  return p->second;
654}
655
656// Resolve a Symbol with another Symbol.  This is only used in the
657// unusual case where there are references to both an unversioned
658// symbol and a symbol with a version, and we then discover that that
659// version is the default version.  Because this is unusual, we do
660// this the slow way, by converting back to an ELF symbol.
661
662template<int size, bool big_endian>
663void
664Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
665{
666  unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
667  elfcpp::Sym_write<size, big_endian> esym(buf);
668  // We don't bother to set the st_name or the st_shndx field.
669  esym.put_st_value(from->value());
670  esym.put_st_size(from->symsize());
671  esym.put_st_info(from->binding(), from->type());
672  esym.put_st_other(from->visibility(), from->nonvis());
673  bool is_ordinary;
674  unsigned int shndx = from->shndx(&is_ordinary);
675  this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
676		from->version());
677  if (from->in_reg())
678    to->set_in_reg();
679  if (from->in_dyn())
680    to->set_in_dyn();
681  if (parameters->options().gc_sections())
682    this->gc_mark_dyn_syms(to);
683}
684
685// Record that a symbol is forced to be local by a version script or
686// by visibility.
687
688void
689Symbol_table::force_local(Symbol* sym)
690{
691  if (!sym->is_defined() && !sym->is_common())
692    return;
693  if (sym->is_forced_local())
694    {
695      // We already got this one.
696      return;
697    }
698  sym->set_is_forced_local();
699  this->forced_locals_.push_back(sym);
700}
701
702// Adjust NAME for wrapping, and update *NAME_KEY if necessary.  This
703// is only called for undefined symbols, when at least one --wrap
704// option was used.
705
706const char*
707Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
708{
709  // For some targets, we need to ignore a specific character when
710  // wrapping, and add it back later.
711  char prefix = '\0';
712  if (name[0] == parameters->target().wrap_char())
713    {
714      prefix = name[0];
715      ++name;
716    }
717
718  if (parameters->options().is_wrap(name))
719    {
720      // Turn NAME into __wrap_NAME.
721      std::string s;
722      if (prefix != '\0')
723	s += prefix;
724      s += "__wrap_";
725      s += name;
726
727      // This will give us both the old and new name in NAMEPOOL_, but
728      // that is OK.  Only the versions we need will wind up in the
729      // real string table in the output file.
730      return this->namepool_.add(s.c_str(), true, name_key);
731    }
732
733  const char* const real_prefix = "__real_";
734  const size_t real_prefix_length = strlen(real_prefix);
735  if (strncmp(name, real_prefix, real_prefix_length) == 0
736      && parameters->options().is_wrap(name + real_prefix_length))
737    {
738      // Turn __real_NAME into NAME.
739      std::string s;
740      if (prefix != '\0')
741	s += prefix;
742      s += name + real_prefix_length;
743      return this->namepool_.add(s.c_str(), true, name_key);
744    }
745
746  return name;
747}
748
749// This is called when we see a symbol NAME/VERSION, and the symbol
750// already exists in the symbol table, and VERSION is marked as being
751// the default version.  SYM is the NAME/VERSION symbol we just added.
752// DEFAULT_IS_NEW is true if this is the first time we have seen the
753// symbol NAME/NULL.  PDEF points to the entry for NAME/NULL.
754
755template<int size, bool big_endian>
756void
757Symbol_table::define_default_version(Sized_symbol<size>* sym,
758				     bool default_is_new,
759				     Symbol_table_type::iterator pdef)
760{
761  if (default_is_new)
762    {
763      // This is the first time we have seen NAME/NULL.  Make
764      // NAME/NULL point to NAME/VERSION, and mark SYM as the default
765      // version.
766      pdef->second = sym;
767      sym->set_is_default();
768    }
769  else if (pdef->second == sym)
770    {
771      // NAME/NULL already points to NAME/VERSION.  Don't mark the
772      // symbol as the default if it is not already the default.
773    }
774  else
775    {
776      // This is the unfortunate case where we already have entries
777      // for both NAME/VERSION and NAME/NULL.  We now see a symbol
778      // NAME/VERSION where VERSION is the default version.  We have
779      // already resolved this new symbol with the existing
780      // NAME/VERSION symbol.
781
782      // It's possible that NAME/NULL and NAME/VERSION are both
783      // defined in regular objects.  This can only happen if one
784      // object file defines foo and another defines foo@@ver.  This
785      // is somewhat obscure, but we call it a multiple definition
786      // error.
787
788      // It's possible that NAME/NULL actually has a version, in which
789      // case it won't be the same as VERSION.  This happens with
790      // ver_test_7.so in the testsuite for the symbol t2_2.  We see
791      // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL.  We
792      // then see an unadorned t2_2 in an object file and give it
793      // version VER1 from the version script.  This looks like a
794      // default definition for VER1, so it looks like we should merge
795      // t2_2/NULL with t2_2/VER1.  That doesn't make sense, but it's
796      // not obvious that this is an error, either.  So we just punt.
797
798      // If one of the symbols has non-default visibility, and the
799      // other is defined in a shared object, then they are different
800      // symbols.
801
802      // Otherwise, we just resolve the symbols as though they were
803      // the same.
804
805      if (pdef->second->version() != NULL)
806	gold_assert(pdef->second->version() != sym->version());
807      else if (sym->visibility() != elfcpp::STV_DEFAULT
808	       && pdef->second->is_from_dynobj())
809	;
810      else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
811	       && sym->is_from_dynobj())
812	;
813      else
814	{
815	  const Sized_symbol<size>* symdef;
816	  symdef = this->get_sized_symbol<size>(pdef->second);
817	  Symbol_table::resolve<size, big_endian>(sym, symdef);
818	  this->make_forwarder(pdef->second, sym);
819	  pdef->second = sym;
820	  sym->set_is_default();
821	}
822    }
823}
824
825// Add one symbol from OBJECT to the symbol table.  NAME is symbol
826// name and VERSION is the version; both are canonicalized.  DEF is
827// whether this is the default version.  ST_SHNDX is the symbol's
828// section index; IS_ORDINARY is whether this is a normal section
829// rather than a special code.
830
831// If IS_DEFAULT_VERSION is true, then this is the definition of a
832// default version of a symbol.  That means that any lookup of
833// NAME/NULL and any lookup of NAME/VERSION should always return the
834// same symbol.  This is obvious for references, but in particular we
835// want to do this for definitions: overriding NAME/NULL should also
836// override NAME/VERSION.  If we don't do that, it would be very hard
837// to override functions in a shared library which uses versioning.
838
839// We implement this by simply making both entries in the hash table
840// point to the same Symbol structure.  That is easy enough if this is
841// the first time we see NAME/NULL or NAME/VERSION, but it is possible
842// that we have seen both already, in which case they will both have
843// independent entries in the symbol table.  We can't simply change
844// the symbol table entry, because we have pointers to the entries
845// attached to the object files.  So we mark the entry attached to the
846// object file as a forwarder, and record it in the forwarders_ map.
847// Note that entries in the hash table will never be marked as
848// forwarders.
849//
850// ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
851// ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
852// for a special section code.  ST_SHNDX may be modified if the symbol
853// is defined in a section being discarded.
854
855template<int size, bool big_endian>
856Sized_symbol<size>*
857Symbol_table::add_from_object(Object* object,
858			      const char* name,
859			      Stringpool::Key name_key,
860			      const char* version,
861			      Stringpool::Key version_key,
862			      bool is_default_version,
863			      const elfcpp::Sym<size, big_endian>& sym,
864			      unsigned int st_shndx,
865			      bool is_ordinary,
866			      unsigned int orig_st_shndx)
867{
868  // Print a message if this symbol is being traced.
869  if (parameters->options().is_trace_symbol(name))
870    {
871      if (orig_st_shndx == elfcpp::SHN_UNDEF)
872        gold_info(_("%s: reference to %s"), object->name().c_str(), name);
873      else
874        gold_info(_("%s: definition of %s"), object->name().c_str(), name);
875    }
876
877  // For an undefined symbol, we may need to adjust the name using
878  // --wrap.
879  if (orig_st_shndx == elfcpp::SHN_UNDEF
880      && parameters->options().any_wrap())
881    {
882      const char* wrap_name = this->wrap_symbol(name, &name_key);
883      if (wrap_name != name)
884	{
885	  // If we see a reference to malloc with version GLIBC_2.0,
886	  // and we turn it into a reference to __wrap_malloc, then we
887	  // discard the version number.  Otherwise the user would be
888	  // required to specify the correct version for
889	  // __wrap_malloc.
890	  version = NULL;
891	  version_key = 0;
892	  name = wrap_name;
893	}
894    }
895
896  Symbol* const snull = NULL;
897  std::pair<typename Symbol_table_type::iterator, bool> ins =
898    this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
899				       snull));
900
901  std::pair<typename Symbol_table_type::iterator, bool> insdefault =
902    std::make_pair(this->table_.end(), false);
903  if (is_default_version)
904    {
905      const Stringpool::Key vnull_key = 0;
906      insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key,
907								     vnull_key),
908						      snull));
909    }
910
911  // ins.first: an iterator, which is a pointer to a pair.
912  // ins.first->first: the key (a pair of name and version).
913  // ins.first->second: the value (Symbol*).
914  // ins.second: true if new entry was inserted, false if not.
915
916  Sized_symbol<size>* ret;
917  bool was_undefined;
918  bool was_common;
919  if (!ins.second)
920    {
921      // We already have an entry for NAME/VERSION.
922      ret = this->get_sized_symbol<size>(ins.first->second);
923      gold_assert(ret != NULL);
924
925      was_undefined = ret->is_undefined();
926      was_common = ret->is_common();
927
928      this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
929		    version);
930      if (parameters->options().gc_sections())
931        this->gc_mark_dyn_syms(ret);
932
933      if (is_default_version)
934	this->define_default_version<size, big_endian>(ret, insdefault.second,
935						       insdefault.first);
936    }
937  else
938    {
939      // This is the first time we have seen NAME/VERSION.
940      gold_assert(ins.first->second == NULL);
941
942      if (is_default_version && !insdefault.second)
943	{
944	  // We already have an entry for NAME/NULL.  If we override
945	  // it, then change it to NAME/VERSION.
946	  ret = this->get_sized_symbol<size>(insdefault.first->second);
947
948	  was_undefined = ret->is_undefined();
949	  was_common = ret->is_common();
950
951	  this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
952			version);
953          if (parameters->options().gc_sections())
954            this->gc_mark_dyn_syms(ret);
955	  ins.first->second = ret;
956	}
957      else
958	{
959	  was_undefined = false;
960	  was_common = false;
961
962	  Sized_target<size, big_endian>* target =
963	    parameters->sized_target<size, big_endian>();
964	  if (!target->has_make_symbol())
965	    ret = new Sized_symbol<size>();
966	  else
967	    {
968	      ret = target->make_symbol();
969	      if (ret == NULL)
970		{
971		  // This means that we don't want a symbol table
972		  // entry after all.
973		  if (!is_default_version)
974		    this->table_.erase(ins.first);
975		  else
976		    {
977		      this->table_.erase(insdefault.first);
978		      // Inserting INSDEFAULT invalidated INS.
979		      this->table_.erase(std::make_pair(name_key,
980							version_key));
981		    }
982		  return NULL;
983		}
984	    }
985
986	  ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
987
988	  ins.first->second = ret;
989	  if (is_default_version)
990	    {
991	      // This is the first time we have seen NAME/NULL.  Point
992	      // it at the new entry for NAME/VERSION.
993	      gold_assert(insdefault.second);
994	      insdefault.first->second = ret;
995	    }
996	}
997
998      if (is_default_version)
999	ret->set_is_default();
1000    }
1001
1002  // Record every time we see a new undefined symbol, to speed up
1003  // archive groups.
1004  if (!was_undefined && ret->is_undefined())
1005    {
1006      ++this->saw_undefined_;
1007      if (parameters->options().has_plugins())
1008	parameters->options().plugins()->new_undefined_symbol(ret);
1009    }
1010
1011  // Keep track of common symbols, to speed up common symbol
1012  // allocation.
1013  if (!was_common && ret->is_common())
1014    {
1015      if (ret->type() == elfcpp::STT_TLS)
1016	this->tls_commons_.push_back(ret);
1017      else if (!is_ordinary
1018	       && st_shndx == parameters->target().small_common_shndx())
1019	this->small_commons_.push_back(ret);
1020      else if (!is_ordinary
1021	       && st_shndx == parameters->target().large_common_shndx())
1022	this->large_commons_.push_back(ret);
1023      else
1024	this->commons_.push_back(ret);
1025    }
1026
1027  // If we're not doing a relocatable link, then any symbol with
1028  // hidden or internal visibility is local.
1029  if ((ret->visibility() == elfcpp::STV_HIDDEN
1030       || ret->visibility() == elfcpp::STV_INTERNAL)
1031      && (ret->binding() == elfcpp::STB_GLOBAL
1032	  || ret->binding() == elfcpp::STB_GNU_UNIQUE
1033	  || ret->binding() == elfcpp::STB_WEAK)
1034      && !parameters->options().relocatable())
1035    this->force_local(ret);
1036
1037  return ret;
1038}
1039
1040// Add all the symbols in a relocatable object to the hash table.
1041
1042template<int size, bool big_endian>
1043void
1044Symbol_table::add_from_relobj(
1045    Sized_relobj<size, big_endian>* relobj,
1046    const unsigned char* syms,
1047    size_t count,
1048    size_t symndx_offset,
1049    const char* sym_names,
1050    size_t sym_name_size,
1051    typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1052    size_t* defined)
1053{
1054  *defined = 0;
1055
1056  gold_assert(size == parameters->target().get_size());
1057
1058  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1059
1060  const bool just_symbols = relobj->just_symbols();
1061
1062  const unsigned char* p = syms;
1063  for (size_t i = 0; i < count; ++i, p += sym_size)
1064    {
1065      (*sympointers)[i] = NULL;
1066
1067      elfcpp::Sym<size, big_endian> sym(p);
1068
1069      unsigned int st_name = sym.get_st_name();
1070      if (st_name >= sym_name_size)
1071	{
1072	  relobj->error(_("bad global symbol name offset %u at %zu"),
1073			st_name, i);
1074	  continue;
1075	}
1076
1077      const char* name = sym_names + st_name;
1078
1079      bool is_ordinary;
1080      unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1081						       sym.get_st_shndx(),
1082						       &is_ordinary);
1083      unsigned int orig_st_shndx = st_shndx;
1084      if (!is_ordinary)
1085	orig_st_shndx = elfcpp::SHN_UNDEF;
1086
1087      if (st_shndx != elfcpp::SHN_UNDEF)
1088	++*defined;
1089
1090      // A symbol defined in a section which we are not including must
1091      // be treated as an undefined symbol.
1092      bool is_defined_in_discarded_section = false;
1093      if (st_shndx != elfcpp::SHN_UNDEF
1094	  && is_ordinary
1095	  && !relobj->is_section_included(st_shndx)
1096          && !this->is_section_folded(relobj, st_shndx))
1097	{
1098	  st_shndx = elfcpp::SHN_UNDEF;
1099	  is_defined_in_discarded_section = true;
1100	}
1101
1102      // In an object file, an '@' in the name separates the symbol
1103      // name from the version name.  If there are two '@' characters,
1104      // this is the default version.
1105      const char* ver = strchr(name, '@');
1106      Stringpool::Key ver_key = 0;
1107      int namelen = 0;
1108      // IS_DEFAULT_VERSION: is the version default?
1109      // IS_FORCED_LOCAL: is the symbol forced local?
1110      bool is_default_version = false;
1111      bool is_forced_local = false;
1112
1113      if (ver != NULL)
1114        {
1115          // The symbol name is of the form foo@VERSION or foo@@VERSION
1116          namelen = ver - name;
1117          ++ver;
1118	  if (*ver == '@')
1119	    {
1120	      is_default_version = true;
1121	      ++ver;
1122	    }
1123	  ver = this->namepool_.add(ver, true, &ver_key);
1124        }
1125      // We don't want to assign a version to an undefined symbol,
1126      // even if it is listed in the version script.  FIXME: What
1127      // about a common symbol?
1128      else
1129	{
1130	  namelen = strlen(name);
1131	  if (!this->version_script_.empty()
1132	      && st_shndx != elfcpp::SHN_UNDEF)
1133	    {
1134	      // The symbol name did not have a version, but the
1135	      // version script may assign a version anyway.
1136	      std::string version;
1137	      bool is_global;
1138	      if (this->version_script_.get_symbol_version(name, &version,
1139							   &is_global))
1140		{
1141		  if (!is_global)
1142		    is_forced_local = true;
1143		  else if (!version.empty())
1144		    {
1145		      ver = this->namepool_.add_with_length(version.c_str(),
1146							    version.length(),
1147							    true,
1148							    &ver_key);
1149		      is_default_version = true;
1150		    }
1151		}
1152	    }
1153	}
1154
1155      elfcpp::Sym<size, big_endian>* psym = &sym;
1156      unsigned char symbuf[sym_size];
1157      elfcpp::Sym<size, big_endian> sym2(symbuf);
1158      if (just_symbols)
1159	{
1160	  memcpy(symbuf, p, sym_size);
1161	  elfcpp::Sym_write<size, big_endian> sw(symbuf);
1162	  if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1163	    {
1164	      // Symbol values in object files are section relative.
1165	      // This is normally what we want, but since here we are
1166	      // converting the symbol to absolute we need to add the
1167	      // section address.  The section address in an object
1168	      // file is normally zero, but people can use a linker
1169	      // script to change it.
1170	      sw.put_st_value(sym.get_st_value()
1171			      + relobj->section_address(orig_st_shndx));
1172	    }
1173	  st_shndx = elfcpp::SHN_ABS;
1174	  is_ordinary = false;
1175	  psym = &sym2;
1176	}
1177
1178      // Fix up visibility if object has no-export set.
1179      if (relobj->no_export()
1180	  && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1181        {
1182	  // We may have copied symbol already above.
1183	  if (psym != &sym2)
1184	    {
1185	      memcpy(symbuf, p, sym_size);
1186	      psym = &sym2;
1187	    }
1188
1189	  elfcpp::STV visibility = sym2.get_st_visibility();
1190	  if (visibility == elfcpp::STV_DEFAULT
1191	      || visibility == elfcpp::STV_PROTECTED)
1192	    {
1193	      elfcpp::Sym_write<size, big_endian> sw(symbuf);
1194	      unsigned char nonvis = sym2.get_st_nonvis();
1195	      sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1196	    }
1197        }
1198
1199      Stringpool::Key name_key;
1200      name = this->namepool_.add_with_length(name, namelen, true,
1201					     &name_key);
1202
1203      Sized_symbol<size>* res;
1204      res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1205				  is_default_version, *psym, st_shndx,
1206				  is_ordinary, orig_st_shndx);
1207
1208      // If building a shared library using garbage collection, do not
1209      // treat externally visible symbols as garbage.
1210      if (parameters->options().gc_sections()
1211          && parameters->options().shared())
1212        this->gc_mark_symbol_for_shlib(res);
1213
1214      if (is_forced_local)
1215	this->force_local(res);
1216
1217      if (is_defined_in_discarded_section)
1218	res->set_is_defined_in_discarded_section();
1219
1220      (*sympointers)[i] = res;
1221    }
1222}
1223
1224// Add a symbol from a plugin-claimed file.
1225
1226template<int size, bool big_endian>
1227Symbol*
1228Symbol_table::add_from_pluginobj(
1229    Sized_pluginobj<size, big_endian>* obj,
1230    const char* name,
1231    const char* ver,
1232    elfcpp::Sym<size, big_endian>* sym)
1233{
1234  unsigned int st_shndx = sym->get_st_shndx();
1235  bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1236
1237  Stringpool::Key ver_key = 0;
1238  bool is_default_version = false;
1239  bool is_forced_local = false;
1240
1241  if (ver != NULL)
1242    {
1243      ver = this->namepool_.add(ver, true, &ver_key);
1244    }
1245  // We don't want to assign a version to an undefined symbol,
1246  // even if it is listed in the version script.  FIXME: What
1247  // about a common symbol?
1248  else
1249    {
1250      if (!this->version_script_.empty()
1251          && st_shndx != elfcpp::SHN_UNDEF)
1252        {
1253          // The symbol name did not have a version, but the
1254          // version script may assign a version anyway.
1255          std::string version;
1256	  bool is_global;
1257          if (this->version_script_.get_symbol_version(name, &version,
1258						       &is_global))
1259            {
1260	      if (!is_global)
1261		is_forced_local = true;
1262	      else if (!version.empty())
1263                {
1264                  ver = this->namepool_.add_with_length(version.c_str(),
1265                                                        version.length(),
1266                                                        true,
1267                                                        &ver_key);
1268                  is_default_version = true;
1269                }
1270            }
1271        }
1272    }
1273
1274  Stringpool::Key name_key;
1275  name = this->namepool_.add(name, true, &name_key);
1276
1277  Sized_symbol<size>* res;
1278  res = this->add_from_object(obj, name, name_key, ver, ver_key,
1279		              is_default_version, *sym, st_shndx,
1280			      is_ordinary, st_shndx);
1281
1282  if (is_forced_local)
1283    this->force_local(res);
1284
1285  return res;
1286}
1287
1288// Add all the symbols in a dynamic object to the hash table.
1289
1290template<int size, bool big_endian>
1291void
1292Symbol_table::add_from_dynobj(
1293    Sized_dynobj<size, big_endian>* dynobj,
1294    const unsigned char* syms,
1295    size_t count,
1296    const char* sym_names,
1297    size_t sym_name_size,
1298    const unsigned char* versym,
1299    size_t versym_size,
1300    const std::vector<const char*>* version_map,
1301    typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1302    size_t* defined)
1303{
1304  *defined = 0;
1305
1306  gold_assert(size == parameters->target().get_size());
1307
1308  if (dynobj->just_symbols())
1309    {
1310      gold_error(_("--just-symbols does not make sense with a shared object"));
1311      return;
1312    }
1313
1314  if (versym != NULL && versym_size / 2 < count)
1315    {
1316      dynobj->error(_("too few symbol versions"));
1317      return;
1318    }
1319
1320  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1321
1322  // We keep a list of all STT_OBJECT symbols, so that we can resolve
1323  // weak aliases.  This is necessary because if the dynamic object
1324  // provides the same variable under two names, one of which is a
1325  // weak definition, and the regular object refers to the weak
1326  // definition, we have to put both the weak definition and the
1327  // strong definition into the dynamic symbol table.  Given a weak
1328  // definition, the only way that we can find the corresponding
1329  // strong definition, if any, is to search the symbol table.
1330  std::vector<Sized_symbol<size>*> object_symbols;
1331
1332  const unsigned char* p = syms;
1333  const unsigned char* vs = versym;
1334  for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1335    {
1336      elfcpp::Sym<size, big_endian> sym(p);
1337
1338      if (sympointers != NULL)
1339	(*sympointers)[i] = NULL;
1340
1341      // Ignore symbols with local binding or that have
1342      // internal or hidden visibility.
1343      if (sym.get_st_bind() == elfcpp::STB_LOCAL
1344          || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1345          || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1346	continue;
1347
1348      // A protected symbol in a shared library must be treated as a
1349      // normal symbol when viewed from outside the shared library.
1350      // Implement this by overriding the visibility here.
1351      elfcpp::Sym<size, big_endian>* psym = &sym;
1352      unsigned char symbuf[sym_size];
1353      elfcpp::Sym<size, big_endian> sym2(symbuf);
1354      if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1355	{
1356	  memcpy(symbuf, p, sym_size);
1357	  elfcpp::Sym_write<size, big_endian> sw(symbuf);
1358	  sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1359	  psym = &sym2;
1360	}
1361
1362      unsigned int st_name = psym->get_st_name();
1363      if (st_name >= sym_name_size)
1364	{
1365	  dynobj->error(_("bad symbol name offset %u at %zu"),
1366			st_name, i);
1367	  continue;
1368	}
1369
1370      const char* name = sym_names + st_name;
1371
1372      bool is_ordinary;
1373      unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1374						       &is_ordinary);
1375
1376      if (st_shndx != elfcpp::SHN_UNDEF)
1377	++*defined;
1378
1379      Sized_symbol<size>* res;
1380
1381      if (versym == NULL)
1382	{
1383	  Stringpool::Key name_key;
1384	  name = this->namepool_.add(name, true, &name_key);
1385	  res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1386				      false, *psym, st_shndx, is_ordinary,
1387				      st_shndx);
1388	}
1389      else
1390	{
1391	  // Read the version information.
1392
1393	  unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1394
1395	  bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1396	  v &= elfcpp::VERSYM_VERSION;
1397
1398	  // The Sun documentation says that V can be VER_NDX_LOCAL,
1399	  // or VER_NDX_GLOBAL, or a version index.  The meaning of
1400	  // VER_NDX_LOCAL is defined as "Symbol has local scope."
1401	  // The old GNU linker will happily generate VER_NDX_LOCAL
1402	  // for an undefined symbol.  I don't know what the Sun
1403	  // linker will generate.
1404
1405	  if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1406	      && st_shndx != elfcpp::SHN_UNDEF)
1407	    {
1408	      // This symbol should not be visible outside the object.
1409	      continue;
1410	    }
1411
1412	  // At this point we are definitely going to add this symbol.
1413	  Stringpool::Key name_key;
1414	  name = this->namepool_.add(name, true, &name_key);
1415
1416	  if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1417	      || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1418	    {
1419	      // This symbol does not have a version.
1420	      res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1421					  false, *psym, st_shndx, is_ordinary,
1422					  st_shndx);
1423	    }
1424	  else
1425	    {
1426	      if (v >= version_map->size())
1427		{
1428		  dynobj->error(_("versym for symbol %zu out of range: %u"),
1429				i, v);
1430		  continue;
1431		}
1432
1433	      const char* version = (*version_map)[v];
1434	      if (version == NULL)
1435		{
1436		  dynobj->error(_("versym for symbol %zu has no name: %u"),
1437				i, v);
1438		  continue;
1439		}
1440
1441	      Stringpool::Key version_key;
1442	      version = this->namepool_.add(version, true, &version_key);
1443
1444	      // If this is an absolute symbol, and the version name
1445	      // and symbol name are the same, then this is the
1446	      // version definition symbol.  These symbols exist to
1447	      // support using -u to pull in particular versions.  We
1448	      // do not want to record a version for them.
1449	      if (st_shndx == elfcpp::SHN_ABS
1450		  && !is_ordinary
1451		  && name_key == version_key)
1452		res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1453					    false, *psym, st_shndx, is_ordinary,
1454					    st_shndx);
1455	      else
1456		{
1457		  const bool is_default_version =
1458		    !hidden && st_shndx != elfcpp::SHN_UNDEF;
1459		  res = this->add_from_object(dynobj, name, name_key, version,
1460					      version_key, is_default_version,
1461					      *psym, st_shndx,
1462					      is_ordinary, st_shndx);
1463		}
1464	    }
1465	}
1466
1467      // Note that it is possible that RES was overridden by an
1468      // earlier object, in which case it can't be aliased here.
1469      if (st_shndx != elfcpp::SHN_UNDEF
1470	  && is_ordinary
1471	  && psym->get_st_type() == elfcpp::STT_OBJECT
1472	  && res->source() == Symbol::FROM_OBJECT
1473	  && res->object() == dynobj)
1474	object_symbols.push_back(res);
1475
1476      if (sympointers != NULL)
1477	(*sympointers)[i] = res;
1478    }
1479
1480  this->record_weak_aliases(&object_symbols);
1481}
1482
1483// This is used to sort weak aliases.  We sort them first by section
1484// index, then by offset, then by weak ahead of strong.
1485
1486template<int size>
1487class Weak_alias_sorter
1488{
1489 public:
1490  bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1491};
1492
1493template<int size>
1494bool
1495Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1496				    const Sized_symbol<size>* s2) const
1497{
1498  bool is_ordinary;
1499  unsigned int s1_shndx = s1->shndx(&is_ordinary);
1500  gold_assert(is_ordinary);
1501  unsigned int s2_shndx = s2->shndx(&is_ordinary);
1502  gold_assert(is_ordinary);
1503  if (s1_shndx != s2_shndx)
1504    return s1_shndx < s2_shndx;
1505
1506  if (s1->value() != s2->value())
1507    return s1->value() < s2->value();
1508  if (s1->binding() != s2->binding())
1509    {
1510      if (s1->binding() == elfcpp::STB_WEAK)
1511	return true;
1512      if (s2->binding() == elfcpp::STB_WEAK)
1513	return false;
1514    }
1515  return std::string(s1->name()) < std::string(s2->name());
1516}
1517
1518// SYMBOLS is a list of object symbols from a dynamic object.  Look
1519// for any weak aliases, and record them so that if we add the weak
1520// alias to the dynamic symbol table, we also add the corresponding
1521// strong symbol.
1522
1523template<int size>
1524void
1525Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1526{
1527  // Sort the vector by section index, then by offset, then by weak
1528  // ahead of strong.
1529  std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1530
1531  // Walk through the vector.  For each weak definition, record
1532  // aliases.
1533  for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1534	 symbols->begin();
1535       p != symbols->end();
1536       ++p)
1537    {
1538      if ((*p)->binding() != elfcpp::STB_WEAK)
1539	continue;
1540
1541      // Build a circular list of weak aliases.  Each symbol points to
1542      // the next one in the circular list.
1543
1544      Sized_symbol<size>* from_sym = *p;
1545      typename std::vector<Sized_symbol<size>*>::const_iterator q;
1546      for (q = p + 1; q != symbols->end(); ++q)
1547	{
1548	  bool dummy;
1549	  if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1550	      || (*q)->value() != from_sym->value())
1551	    break;
1552
1553	  this->weak_aliases_[from_sym] = *q;
1554	  from_sym->set_has_alias();
1555	  from_sym = *q;
1556	}
1557
1558      if (from_sym != *p)
1559	{
1560	  this->weak_aliases_[from_sym] = *p;
1561	  from_sym->set_has_alias();
1562	}
1563
1564      p = q - 1;
1565    }
1566}
1567
1568// Create and return a specially defined symbol.  If ONLY_IF_REF is
1569// true, then only create the symbol if there is a reference to it.
1570// If this does not return NULL, it sets *POLDSYM to the existing
1571// symbol if there is one.  This sets *RESOLVE_OLDSYM if we should
1572// resolve the newly created symbol to the old one.  This
1573// canonicalizes *PNAME and *PVERSION.
1574
1575template<int size, bool big_endian>
1576Sized_symbol<size>*
1577Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1578				    bool only_if_ref,
1579                                    Sized_symbol<size>** poldsym,
1580				    bool* resolve_oldsym)
1581{
1582  *resolve_oldsym = false;
1583
1584  // If the caller didn't give us a version, see if we get one from
1585  // the version script.
1586  std::string v;
1587  bool is_default_version = false;
1588  if (*pversion == NULL)
1589    {
1590      bool is_global;
1591      if (this->version_script_.get_symbol_version(*pname, &v, &is_global))
1592	{
1593	  if (is_global && !v.empty())
1594	    {
1595	      *pversion = v.c_str();
1596	      // If we get the version from a version script, then we
1597	      // are also the default version.
1598	      is_default_version = true;
1599	    }
1600	}
1601    }
1602
1603  Symbol* oldsym;
1604  Sized_symbol<size>* sym;
1605
1606  bool add_to_table = false;
1607  typename Symbol_table_type::iterator add_loc = this->table_.end();
1608  bool add_def_to_table = false;
1609  typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1610
1611  if (only_if_ref)
1612    {
1613      oldsym = this->lookup(*pname, *pversion);
1614      if (oldsym == NULL && is_default_version)
1615	oldsym = this->lookup(*pname, NULL);
1616      if (oldsym == NULL || !oldsym->is_undefined())
1617	return NULL;
1618
1619      *pname = oldsym->name();
1620      if (!is_default_version)
1621	*pversion = oldsym->version();
1622    }
1623  else
1624    {
1625      // Canonicalize NAME and VERSION.
1626      Stringpool::Key name_key;
1627      *pname = this->namepool_.add(*pname, true, &name_key);
1628
1629      Stringpool::Key version_key = 0;
1630      if (*pversion != NULL)
1631	*pversion = this->namepool_.add(*pversion, true, &version_key);
1632
1633      Symbol* const snull = NULL;
1634      std::pair<typename Symbol_table_type::iterator, bool> ins =
1635	this->table_.insert(std::make_pair(std::make_pair(name_key,
1636							  version_key),
1637					   snull));
1638
1639      std::pair<typename Symbol_table_type::iterator, bool> insdefault =
1640	std::make_pair(this->table_.end(), false);
1641      if (is_default_version)
1642	{
1643	  const Stringpool::Key vnull = 0;
1644	  insdefault =
1645	    this->table_.insert(std::make_pair(std::make_pair(name_key,
1646							      vnull),
1647					       snull));
1648	}
1649
1650      if (!ins.second)
1651	{
1652	  // We already have a symbol table entry for NAME/VERSION.
1653	  oldsym = ins.first->second;
1654	  gold_assert(oldsym != NULL);
1655
1656	  if (is_default_version)
1657	    {
1658	      Sized_symbol<size>* soldsym =
1659		this->get_sized_symbol<size>(oldsym);
1660	      this->define_default_version<size, big_endian>(soldsym,
1661							     insdefault.second,
1662							     insdefault.first);
1663	    }
1664	}
1665      else
1666	{
1667	  // We haven't seen this symbol before.
1668	  gold_assert(ins.first->second == NULL);
1669
1670	  add_to_table = true;
1671	  add_loc = ins.first;
1672
1673	  if (is_default_version && !insdefault.second)
1674	    {
1675	      // We are adding NAME/VERSION, and it is the default
1676	      // version.  We already have an entry for NAME/NULL.
1677	      oldsym = insdefault.first->second;
1678	      *resolve_oldsym = true;
1679	    }
1680	  else
1681	    {
1682	      oldsym = NULL;
1683
1684	      if (is_default_version)
1685		{
1686		  add_def_to_table = true;
1687		  add_def_loc = insdefault.first;
1688		}
1689	    }
1690	}
1691    }
1692
1693  const Target& target = parameters->target();
1694  if (!target.has_make_symbol())
1695    sym = new Sized_symbol<size>();
1696  else
1697    {
1698      Sized_target<size, big_endian>* sized_target =
1699	parameters->sized_target<size, big_endian>();
1700      sym = sized_target->make_symbol();
1701      if (sym == NULL)
1702        return NULL;
1703    }
1704
1705  if (add_to_table)
1706    add_loc->second = sym;
1707  else
1708    gold_assert(oldsym != NULL);
1709
1710  if (add_def_to_table)
1711    add_def_loc->second = sym;
1712
1713  *poldsym = this->get_sized_symbol<size>(oldsym);
1714
1715  return sym;
1716}
1717
1718// Define a symbol based on an Output_data.
1719
1720Symbol*
1721Symbol_table::define_in_output_data(const char* name,
1722				    const char* version,
1723				    Defined defined,
1724				    Output_data* od,
1725				    uint64_t value,
1726				    uint64_t symsize,
1727				    elfcpp::STT type,
1728				    elfcpp::STB binding,
1729				    elfcpp::STV visibility,
1730				    unsigned char nonvis,
1731				    bool offset_is_from_end,
1732				    bool only_if_ref)
1733{
1734  if (parameters->target().get_size() == 32)
1735    {
1736#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1737      return this->do_define_in_output_data<32>(name, version, defined, od,
1738                                                value, symsize, type, binding,
1739                                                visibility, nonvis,
1740                                                offset_is_from_end,
1741                                                only_if_ref);
1742#else
1743      gold_unreachable();
1744#endif
1745    }
1746  else if (parameters->target().get_size() == 64)
1747    {
1748#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1749      return this->do_define_in_output_data<64>(name, version, defined, od,
1750                                                value, symsize, type, binding,
1751                                                visibility, nonvis,
1752                                                offset_is_from_end,
1753                                                only_if_ref);
1754#else
1755      gold_unreachable();
1756#endif
1757    }
1758  else
1759    gold_unreachable();
1760}
1761
1762// Define a symbol in an Output_data, sized version.
1763
1764template<int size>
1765Sized_symbol<size>*
1766Symbol_table::do_define_in_output_data(
1767    const char* name,
1768    const char* version,
1769    Defined defined,
1770    Output_data* od,
1771    typename elfcpp::Elf_types<size>::Elf_Addr value,
1772    typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1773    elfcpp::STT type,
1774    elfcpp::STB binding,
1775    elfcpp::STV visibility,
1776    unsigned char nonvis,
1777    bool offset_is_from_end,
1778    bool only_if_ref)
1779{
1780  Sized_symbol<size>* sym;
1781  Sized_symbol<size>* oldsym;
1782  bool resolve_oldsym;
1783
1784  if (parameters->target().is_big_endian())
1785    {
1786#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1787      sym = this->define_special_symbol<size, true>(&name, &version,
1788						    only_if_ref, &oldsym,
1789						    &resolve_oldsym);
1790#else
1791      gold_unreachable();
1792#endif
1793    }
1794  else
1795    {
1796#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1797      sym = this->define_special_symbol<size, false>(&name, &version,
1798						     only_if_ref, &oldsym,
1799						     &resolve_oldsym);
1800#else
1801      gold_unreachable();
1802#endif
1803    }
1804
1805  if (sym == NULL)
1806    return NULL;
1807
1808  sym->init_output_data(name, version, od, value, symsize, type, binding,
1809			visibility, nonvis, offset_is_from_end);
1810
1811  if (oldsym == NULL)
1812    {
1813      if (binding == elfcpp::STB_LOCAL
1814	  || this->version_script_.symbol_is_local(name))
1815	this->force_local(sym);
1816      else if (version != NULL)
1817	sym->set_is_default();
1818      return sym;
1819    }
1820
1821  if (Symbol_table::should_override_with_special(oldsym, defined))
1822    this->override_with_special(oldsym, sym);
1823
1824  if (resolve_oldsym)
1825    return sym;
1826  else
1827    {
1828      delete sym;
1829      return oldsym;
1830    }
1831}
1832
1833// Define a symbol based on an Output_segment.
1834
1835Symbol*
1836Symbol_table::define_in_output_segment(const char* name,
1837				       const char* version,
1838				       Defined defined,
1839				       Output_segment* os,
1840				       uint64_t value,
1841				       uint64_t symsize,
1842				       elfcpp::STT type,
1843				       elfcpp::STB binding,
1844				       elfcpp::STV visibility,
1845				       unsigned char nonvis,
1846				       Symbol::Segment_offset_base offset_base,
1847				       bool only_if_ref)
1848{
1849  if (parameters->target().get_size() == 32)
1850    {
1851#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1852      return this->do_define_in_output_segment<32>(name, version, defined, os,
1853                                                   value, symsize, type,
1854                                                   binding, visibility, nonvis,
1855                                                   offset_base, only_if_ref);
1856#else
1857      gold_unreachable();
1858#endif
1859    }
1860  else if (parameters->target().get_size() == 64)
1861    {
1862#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1863      return this->do_define_in_output_segment<64>(name, version, defined, os,
1864                                                   value, symsize, type,
1865                                                   binding, visibility, nonvis,
1866                                                   offset_base, only_if_ref);
1867#else
1868      gold_unreachable();
1869#endif
1870    }
1871  else
1872    gold_unreachable();
1873}
1874
1875// Define a symbol in an Output_segment, sized version.
1876
1877template<int size>
1878Sized_symbol<size>*
1879Symbol_table::do_define_in_output_segment(
1880    const char* name,
1881    const char* version,
1882    Defined defined,
1883    Output_segment* os,
1884    typename elfcpp::Elf_types<size>::Elf_Addr value,
1885    typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1886    elfcpp::STT type,
1887    elfcpp::STB binding,
1888    elfcpp::STV visibility,
1889    unsigned char nonvis,
1890    Symbol::Segment_offset_base offset_base,
1891    bool only_if_ref)
1892{
1893  Sized_symbol<size>* sym;
1894  Sized_symbol<size>* oldsym;
1895  bool resolve_oldsym;
1896
1897  if (parameters->target().is_big_endian())
1898    {
1899#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1900      sym = this->define_special_symbol<size, true>(&name, &version,
1901						    only_if_ref, &oldsym,
1902						    &resolve_oldsym);
1903#else
1904      gold_unreachable();
1905#endif
1906    }
1907  else
1908    {
1909#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1910      sym = this->define_special_symbol<size, false>(&name, &version,
1911						     only_if_ref, &oldsym,
1912						     &resolve_oldsym);
1913#else
1914      gold_unreachable();
1915#endif
1916    }
1917
1918  if (sym == NULL)
1919    return NULL;
1920
1921  sym->init_output_segment(name, version, os, value, symsize, type, binding,
1922			   visibility, nonvis, offset_base);
1923
1924  if (oldsym == NULL)
1925    {
1926      if (binding == elfcpp::STB_LOCAL
1927	  || this->version_script_.symbol_is_local(name))
1928	this->force_local(sym);
1929      else if (version != NULL)
1930	sym->set_is_default();
1931      return sym;
1932    }
1933
1934  if (Symbol_table::should_override_with_special(oldsym, defined))
1935    this->override_with_special(oldsym, sym);
1936
1937  if (resolve_oldsym)
1938    return sym;
1939  else
1940    {
1941      delete sym;
1942      return oldsym;
1943    }
1944}
1945
1946// Define a special symbol with a constant value.  It is a multiple
1947// definition error if this symbol is already defined.
1948
1949Symbol*
1950Symbol_table::define_as_constant(const char* name,
1951				 const char* version,
1952				 Defined defined,
1953				 uint64_t value,
1954				 uint64_t symsize,
1955				 elfcpp::STT type,
1956				 elfcpp::STB binding,
1957				 elfcpp::STV visibility,
1958				 unsigned char nonvis,
1959				 bool only_if_ref,
1960                                 bool force_override)
1961{
1962  if (parameters->target().get_size() == 32)
1963    {
1964#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1965      return this->do_define_as_constant<32>(name, version, defined, value,
1966                                             symsize, type, binding,
1967                                             visibility, nonvis, only_if_ref,
1968                                             force_override);
1969#else
1970      gold_unreachable();
1971#endif
1972    }
1973  else if (parameters->target().get_size() == 64)
1974    {
1975#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1976      return this->do_define_as_constant<64>(name, version, defined, value,
1977                                             symsize, type, binding,
1978                                             visibility, nonvis, only_if_ref,
1979                                             force_override);
1980#else
1981      gold_unreachable();
1982#endif
1983    }
1984  else
1985    gold_unreachable();
1986}
1987
1988// Define a symbol as a constant, sized version.
1989
1990template<int size>
1991Sized_symbol<size>*
1992Symbol_table::do_define_as_constant(
1993    const char* name,
1994    const char* version,
1995    Defined defined,
1996    typename elfcpp::Elf_types<size>::Elf_Addr value,
1997    typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1998    elfcpp::STT type,
1999    elfcpp::STB binding,
2000    elfcpp::STV visibility,
2001    unsigned char nonvis,
2002    bool only_if_ref,
2003    bool force_override)
2004{
2005  Sized_symbol<size>* sym;
2006  Sized_symbol<size>* oldsym;
2007  bool resolve_oldsym;
2008
2009  if (parameters->target().is_big_endian())
2010    {
2011#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2012      sym = this->define_special_symbol<size, true>(&name, &version,
2013						    only_if_ref, &oldsym,
2014						    &resolve_oldsym);
2015#else
2016      gold_unreachable();
2017#endif
2018    }
2019  else
2020    {
2021#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2022      sym = this->define_special_symbol<size, false>(&name, &version,
2023						     only_if_ref, &oldsym,
2024						     &resolve_oldsym);
2025#else
2026      gold_unreachable();
2027#endif
2028    }
2029
2030  if (sym == NULL)
2031    return NULL;
2032
2033  sym->init_constant(name, version, value, symsize, type, binding, visibility,
2034		     nonvis);
2035
2036  if (oldsym == NULL)
2037    {
2038      // Version symbols are absolute symbols with name == version.
2039      // We don't want to force them to be local.
2040      if ((version == NULL
2041	   || name != version
2042	   || value != 0)
2043	  && (binding == elfcpp::STB_LOCAL
2044	      || this->version_script_.symbol_is_local(name)))
2045	this->force_local(sym);
2046      else if (version != NULL
2047	       && (name != version || value != 0))
2048	sym->set_is_default();
2049      return sym;
2050    }
2051
2052  if (force_override
2053      || Symbol_table::should_override_with_special(oldsym, defined))
2054    this->override_with_special(oldsym, sym);
2055
2056  if (resolve_oldsym)
2057    return sym;
2058  else
2059    {
2060      delete sym;
2061      return oldsym;
2062    }
2063}
2064
2065// Define a set of symbols in output sections.
2066
2067void
2068Symbol_table::define_symbols(const Layout* layout, int count,
2069			     const Define_symbol_in_section* p,
2070			     bool only_if_ref)
2071{
2072  for (int i = 0; i < count; ++i, ++p)
2073    {
2074      Output_section* os = layout->find_output_section(p->output_section);
2075      if (os != NULL)
2076	this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2077				    p->size, p->type, p->binding,
2078				    p->visibility, p->nonvis,
2079				    p->offset_is_from_end,
2080				    only_if_ref || p->only_if_ref);
2081      else
2082	this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2083				 p->type, p->binding, p->visibility, p->nonvis,
2084				 only_if_ref || p->only_if_ref,
2085                                 false);
2086    }
2087}
2088
2089// Define a set of symbols in output segments.
2090
2091void
2092Symbol_table::define_symbols(const Layout* layout, int count,
2093			     const Define_symbol_in_segment* p,
2094			     bool only_if_ref)
2095{
2096  for (int i = 0; i < count; ++i, ++p)
2097    {
2098      Output_segment* os = layout->find_output_segment(p->segment_type,
2099						       p->segment_flags_set,
2100						       p->segment_flags_clear);
2101      if (os != NULL)
2102	this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2103				       p->size, p->type, p->binding,
2104				       p->visibility, p->nonvis,
2105				       p->offset_base,
2106				       only_if_ref || p->only_if_ref);
2107      else
2108	this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2109				 p->type, p->binding, p->visibility, p->nonvis,
2110				 only_if_ref || p->only_if_ref,
2111                                 false);
2112    }
2113}
2114
2115// Define CSYM using a COPY reloc.  POSD is the Output_data where the
2116// symbol should be defined--typically a .dyn.bss section.  VALUE is
2117// the offset within POSD.
2118
2119template<int size>
2120void
2121Symbol_table::define_with_copy_reloc(
2122    Sized_symbol<size>* csym,
2123    Output_data* posd,
2124    typename elfcpp::Elf_types<size>::Elf_Addr value)
2125{
2126  gold_assert(csym->is_from_dynobj());
2127  gold_assert(!csym->is_copied_from_dynobj());
2128  Object* object = csym->object();
2129  gold_assert(object->is_dynamic());
2130  Dynobj* dynobj = static_cast<Dynobj*>(object);
2131
2132  // Our copied variable has to override any variable in a shared
2133  // library.
2134  elfcpp::STB binding = csym->binding();
2135  if (binding == elfcpp::STB_WEAK)
2136    binding = elfcpp::STB_GLOBAL;
2137
2138  this->define_in_output_data(csym->name(), csym->version(), COPY,
2139			      posd, value, csym->symsize(),
2140			      csym->type(), binding,
2141			      csym->visibility(), csym->nonvis(),
2142			      false, false);
2143
2144  csym->set_is_copied_from_dynobj();
2145  csym->set_needs_dynsym_entry();
2146
2147  this->copied_symbol_dynobjs_[csym] = dynobj;
2148
2149  // We have now defined all aliases, but we have not entered them all
2150  // in the copied_symbol_dynobjs_ map.
2151  if (csym->has_alias())
2152    {
2153      Symbol* sym = csym;
2154      while (true)
2155	{
2156	  sym = this->weak_aliases_[sym];
2157	  if (sym == csym)
2158	    break;
2159	  gold_assert(sym->output_data() == posd);
2160
2161	  sym->set_is_copied_from_dynobj();
2162	  this->copied_symbol_dynobjs_[sym] = dynobj;
2163	}
2164    }
2165}
2166
2167// SYM is defined using a COPY reloc.  Return the dynamic object where
2168// the original definition was found.
2169
2170Dynobj*
2171Symbol_table::get_copy_source(const Symbol* sym) const
2172{
2173  gold_assert(sym->is_copied_from_dynobj());
2174  Copied_symbol_dynobjs::const_iterator p =
2175    this->copied_symbol_dynobjs_.find(sym);
2176  gold_assert(p != this->copied_symbol_dynobjs_.end());
2177  return p->second;
2178}
2179
2180// Add any undefined symbols named on the command line.
2181
2182void
2183Symbol_table::add_undefined_symbols_from_command_line(Layout* layout)
2184{
2185  if (parameters->options().any_undefined()
2186      || layout->script_options()->any_unreferenced())
2187    {
2188      if (parameters->target().get_size() == 32)
2189	{
2190#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2191	  this->do_add_undefined_symbols_from_command_line<32>(layout);
2192#else
2193	  gold_unreachable();
2194#endif
2195	}
2196      else if (parameters->target().get_size() == 64)
2197	{
2198#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2199	  this->do_add_undefined_symbols_from_command_line<64>(layout);
2200#else
2201	  gold_unreachable();
2202#endif
2203	}
2204      else
2205	gold_unreachable();
2206    }
2207}
2208
2209template<int size>
2210void
2211Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout)
2212{
2213  for (options::String_set::const_iterator p =
2214	 parameters->options().undefined_begin();
2215       p != parameters->options().undefined_end();
2216       ++p)
2217    this->add_undefined_symbol_from_command_line<size>(p->c_str());
2218
2219  for (Script_options::referenced_const_iterator p =
2220	 layout->script_options()->referenced_begin();
2221       p != layout->script_options()->referenced_end();
2222       ++p)
2223    this->add_undefined_symbol_from_command_line<size>(p->c_str());
2224}
2225
2226template<int size>
2227void
2228Symbol_table::add_undefined_symbol_from_command_line(const char* name)
2229{
2230  if (this->lookup(name) != NULL)
2231    return;
2232
2233  const char* version = NULL;
2234
2235  Sized_symbol<size>* sym;
2236  Sized_symbol<size>* oldsym;
2237  bool resolve_oldsym;
2238  if (parameters->target().is_big_endian())
2239    {
2240#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2241      sym = this->define_special_symbol<size, true>(&name, &version,
2242						    false, &oldsym,
2243						    &resolve_oldsym);
2244#else
2245      gold_unreachable();
2246#endif
2247    }
2248  else
2249    {
2250#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2251      sym = this->define_special_symbol<size, false>(&name, &version,
2252						     false, &oldsym,
2253						     &resolve_oldsym);
2254#else
2255      gold_unreachable();
2256#endif
2257    }
2258
2259  gold_assert(oldsym == NULL);
2260
2261  sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2262		      elfcpp::STV_DEFAULT, 0);
2263  ++this->saw_undefined_;
2264}
2265
2266// Set the dynamic symbol indexes.  INDEX is the index of the first
2267// global dynamic symbol.  Pointers to the symbols are stored into the
2268// vector SYMS.  The names are added to DYNPOOL.  This returns an
2269// updated dynamic symbol index.
2270
2271unsigned int
2272Symbol_table::set_dynsym_indexes(unsigned int index,
2273				 std::vector<Symbol*>* syms,
2274				 Stringpool* dynpool,
2275				 Versions* versions)
2276{
2277  for (Symbol_table_type::iterator p = this->table_.begin();
2278       p != this->table_.end();
2279       ++p)
2280    {
2281      Symbol* sym = p->second;
2282
2283      // Note that SYM may already have a dynamic symbol index, since
2284      // some symbols appear more than once in the symbol table, with
2285      // and without a version.
2286
2287      if (!sym->should_add_dynsym_entry(this))
2288	sym->set_dynsym_index(-1U);
2289      else if (!sym->has_dynsym_index())
2290	{
2291	  sym->set_dynsym_index(index);
2292	  ++index;
2293	  syms->push_back(sym);
2294	  dynpool->add(sym->name(), false, NULL);
2295
2296	  // Record any version information.
2297          if (sym->version() != NULL)
2298            versions->record_version(this, dynpool, sym);
2299
2300	  // If the symbol is defined in a dynamic object and is
2301	  // referenced in a regular object, then mark the dynamic
2302	  // object as needed.  This is used to implement --as-needed.
2303	  if (sym->is_from_dynobj() && sym->in_reg())
2304	    sym->object()->set_is_needed();
2305	}
2306    }
2307
2308  // Finish up the versions.  In some cases this may add new dynamic
2309  // symbols.
2310  index = versions->finalize(this, index, syms);
2311
2312  return index;
2313}
2314
2315// Set the final values for all the symbols.  The index of the first
2316// global symbol in the output file is *PLOCAL_SYMCOUNT.  Record the
2317// file offset OFF.  Add their names to POOL.  Return the new file
2318// offset.  Update *PLOCAL_SYMCOUNT if necessary.
2319
2320off_t
2321Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2322		       size_t dyncount, Stringpool* pool,
2323		       unsigned int* plocal_symcount)
2324{
2325  off_t ret;
2326
2327  gold_assert(*plocal_symcount != 0);
2328  this->first_global_index_ = *plocal_symcount;
2329
2330  this->dynamic_offset_ = dynoff;
2331  this->first_dynamic_global_index_ = dyn_global_index;
2332  this->dynamic_count_ = dyncount;
2333
2334  if (parameters->target().get_size() == 32)
2335    {
2336#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2337      ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2338#else
2339      gold_unreachable();
2340#endif
2341    }
2342  else if (parameters->target().get_size() == 64)
2343    {
2344#if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2345      ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2346#else
2347      gold_unreachable();
2348#endif
2349    }
2350  else
2351    gold_unreachable();
2352
2353  // Now that we have the final symbol table, we can reliably note
2354  // which symbols should get warnings.
2355  this->warnings_.note_warnings(this);
2356
2357  return ret;
2358}
2359
2360// SYM is going into the symbol table at *PINDEX.  Add the name to
2361// POOL, update *PINDEX and *POFF.
2362
2363template<int size>
2364void
2365Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2366				  unsigned int* pindex, off_t* poff)
2367{
2368  sym->set_symtab_index(*pindex);
2369  pool->add(sym->name(), false, NULL);
2370  ++*pindex;
2371  *poff += elfcpp::Elf_sizes<size>::sym_size;
2372}
2373
2374// Set the final value for all the symbols.  This is called after
2375// Layout::finalize, so all the output sections have their final
2376// address.
2377
2378template<int size>
2379off_t
2380Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2381			     unsigned int* plocal_symcount)
2382{
2383  off = align_address(off, size >> 3);
2384  this->offset_ = off;
2385
2386  unsigned int index = *plocal_symcount;
2387  const unsigned int orig_index = index;
2388
2389  // First do all the symbols which have been forced to be local, as
2390  // they must appear before all global symbols.
2391  for (Forced_locals::iterator p = this->forced_locals_.begin();
2392       p != this->forced_locals_.end();
2393       ++p)
2394    {
2395      Symbol* sym = *p;
2396      gold_assert(sym->is_forced_local());
2397      if (this->sized_finalize_symbol<size>(sym))
2398	{
2399	  this->add_to_final_symtab<size>(sym, pool, &index, &off);
2400	  ++*plocal_symcount;
2401	}
2402    }
2403
2404  // Now do all the remaining symbols.
2405  for (Symbol_table_type::iterator p = this->table_.begin();
2406       p != this->table_.end();
2407       ++p)
2408    {
2409      Symbol* sym = p->second;
2410      if (this->sized_finalize_symbol<size>(sym))
2411	this->add_to_final_symtab<size>(sym, pool, &index, &off);
2412    }
2413
2414  this->output_count_ = index - orig_index;
2415
2416  return off;
2417}
2418
2419// Compute the final value of SYM and store status in location PSTATUS.
2420// During relaxation, this may be called multiple times for a symbol to
2421// compute its would-be final value in each relaxation pass.
2422
2423template<int size>
2424typename Sized_symbol<size>::Value_type
2425Symbol_table::compute_final_value(
2426    const Sized_symbol<size>* sym,
2427    Compute_final_value_status* pstatus) const
2428{
2429  typedef typename Sized_symbol<size>::Value_type Value_type;
2430  Value_type value;
2431
2432  switch (sym->source())
2433    {
2434    case Symbol::FROM_OBJECT:
2435      {
2436	bool is_ordinary;
2437	unsigned int shndx = sym->shndx(&is_ordinary);
2438
2439	if (!is_ordinary
2440	    && shndx != elfcpp::SHN_ABS
2441	    && !Symbol::is_common_shndx(shndx))
2442	  {
2443	    *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2444	    return 0;
2445	  }
2446
2447	Object* symobj = sym->object();
2448	if (symobj->is_dynamic())
2449	  {
2450	    value = 0;
2451	    shndx = elfcpp::SHN_UNDEF;
2452	  }
2453	else if (symobj->pluginobj() != NULL)
2454	  {
2455	    value = 0;
2456	    shndx = elfcpp::SHN_UNDEF;
2457	  }
2458	else if (shndx == elfcpp::SHN_UNDEF)
2459	  value = 0;
2460	else if (!is_ordinary
2461		 && (shndx == elfcpp::SHN_ABS
2462		     || Symbol::is_common_shndx(shndx)))
2463	  value = sym->value();
2464	else
2465	  {
2466	    Relobj* relobj = static_cast<Relobj*>(symobj);
2467	    Output_section* os = relobj->output_section(shndx);
2468
2469            if (this->is_section_folded(relobj, shndx))
2470              {
2471                gold_assert(os == NULL);
2472                // Get the os of the section it is folded onto.
2473                Section_id folded = this->icf_->get_folded_section(relobj,
2474                                                                   shndx);
2475                gold_assert(folded.first != NULL);
2476                Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2477		unsigned folded_shndx = folded.second;
2478
2479                os = folded_obj->output_section(folded_shndx);
2480                gold_assert(os != NULL);
2481
2482		// Replace (relobj, shndx) with canonical ICF input section.
2483		shndx = folded_shndx;
2484		relobj = folded_obj;
2485              }
2486
2487            uint64_t secoff64 = relobj->output_section_offset(shndx);
2488 	    if (os == NULL)
2489	      {
2490                bool static_or_reloc = (parameters->doing_static_link() ||
2491                                        parameters->options().relocatable());
2492                gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2493
2494		*pstatus = CFVS_NO_OUTPUT_SECTION;
2495		return 0;
2496	      }
2497
2498            if (secoff64 == -1ULL)
2499              {
2500                // The section needs special handling (e.g., a merge section).
2501
2502	        value = os->output_address(relobj, shndx, sym->value());
2503	      }
2504            else
2505              {
2506                Value_type secoff =
2507                  convert_types<Value_type, uint64_t>(secoff64);
2508	        if (sym->type() == elfcpp::STT_TLS)
2509	          value = sym->value() + os->tls_offset() + secoff;
2510	        else
2511	          value = sym->value() + os->address() + secoff;
2512	      }
2513	  }
2514      }
2515      break;
2516
2517    case Symbol::IN_OUTPUT_DATA:
2518      {
2519	Output_data* od = sym->output_data();
2520	value = sym->value();
2521	if (sym->type() != elfcpp::STT_TLS)
2522	  value += od->address();
2523	else
2524	  {
2525	    Output_section* os = od->output_section();
2526	    gold_assert(os != NULL);
2527	    value += os->tls_offset() + (od->address() - os->address());
2528	  }
2529	if (sym->offset_is_from_end())
2530	  value += od->data_size();
2531      }
2532      break;
2533
2534    case Symbol::IN_OUTPUT_SEGMENT:
2535      {
2536	Output_segment* os = sym->output_segment();
2537	value = sym->value();
2538        if (sym->type() != elfcpp::STT_TLS)
2539	  value += os->vaddr();
2540	switch (sym->offset_base())
2541	  {
2542	  case Symbol::SEGMENT_START:
2543	    break;
2544	  case Symbol::SEGMENT_END:
2545	    value += os->memsz();
2546	    break;
2547	  case Symbol::SEGMENT_BSS:
2548	    value += os->filesz();
2549	    break;
2550	  default:
2551	    gold_unreachable();
2552	  }
2553      }
2554      break;
2555
2556    case Symbol::IS_CONSTANT:
2557      value = sym->value();
2558      break;
2559
2560    case Symbol::IS_UNDEFINED:
2561      value = 0;
2562      break;
2563
2564    default:
2565      gold_unreachable();
2566    }
2567
2568  *pstatus = CFVS_OK;
2569  return value;
2570}
2571
2572// Finalize the symbol SYM.  This returns true if the symbol should be
2573// added to the symbol table, false otherwise.
2574
2575template<int size>
2576bool
2577Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2578{
2579  typedef typename Sized_symbol<size>::Value_type Value_type;
2580
2581  Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2582
2583  // The default version of a symbol may appear twice in the symbol
2584  // table.  We only need to finalize it once.
2585  if (sym->has_symtab_index())
2586    return false;
2587
2588  if (!sym->in_reg())
2589    {
2590      gold_assert(!sym->has_symtab_index());
2591      sym->set_symtab_index(-1U);
2592      gold_assert(sym->dynsym_index() == -1U);
2593      return false;
2594    }
2595
2596  // Compute final symbol value.
2597  Compute_final_value_status status;
2598  Value_type value = this->compute_final_value(sym, &status);
2599
2600  switch (status)
2601    {
2602    case CFVS_OK:
2603      break;
2604    case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2605      {
2606	bool is_ordinary;
2607	unsigned int shndx = sym->shndx(&is_ordinary);
2608	gold_error(_("%s: unsupported symbol section 0x%x"),
2609		   sym->demangled_name().c_str(), shndx);
2610      }
2611      break;
2612    case CFVS_NO_OUTPUT_SECTION:
2613      sym->set_symtab_index(-1U);
2614      return false;
2615    default:
2616      gold_unreachable();
2617    }
2618
2619  sym->set_value(value);
2620
2621  if (parameters->options().strip_all()
2622      || !parameters->options().should_retain_symbol(sym->name()))
2623    {
2624      sym->set_symtab_index(-1U);
2625      return false;
2626    }
2627
2628  return true;
2629}
2630
2631// Write out the global symbols.
2632
2633void
2634Symbol_table::write_globals(const Stringpool* sympool,
2635			    const Stringpool* dynpool,
2636			    Output_symtab_xindex* symtab_xindex,
2637			    Output_symtab_xindex* dynsym_xindex,
2638			    Output_file* of) const
2639{
2640  switch (parameters->size_and_endianness())
2641    {
2642#ifdef HAVE_TARGET_32_LITTLE
2643    case Parameters::TARGET_32_LITTLE:
2644      this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2645					   dynsym_xindex, of);
2646      break;
2647#endif
2648#ifdef HAVE_TARGET_32_BIG
2649    case Parameters::TARGET_32_BIG:
2650      this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2651					  dynsym_xindex, of);
2652      break;
2653#endif
2654#ifdef HAVE_TARGET_64_LITTLE
2655    case Parameters::TARGET_64_LITTLE:
2656      this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2657					   dynsym_xindex, of);
2658      break;
2659#endif
2660#ifdef HAVE_TARGET_64_BIG
2661    case Parameters::TARGET_64_BIG:
2662      this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2663					  dynsym_xindex, of);
2664      break;
2665#endif
2666    default:
2667      gold_unreachable();
2668    }
2669}
2670
2671// Write out the global symbols.
2672
2673template<int size, bool big_endian>
2674void
2675Symbol_table::sized_write_globals(const Stringpool* sympool,
2676				  const Stringpool* dynpool,
2677				  Output_symtab_xindex* symtab_xindex,
2678				  Output_symtab_xindex* dynsym_xindex,
2679				  Output_file* of) const
2680{
2681  const Target& target = parameters->target();
2682
2683  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2684
2685  const unsigned int output_count = this->output_count_;
2686  const section_size_type oview_size = output_count * sym_size;
2687  const unsigned int first_global_index = this->first_global_index_;
2688  unsigned char* psyms;
2689  if (this->offset_ == 0 || output_count == 0)
2690    psyms = NULL;
2691  else
2692    psyms = of->get_output_view(this->offset_, oview_size);
2693
2694  const unsigned int dynamic_count = this->dynamic_count_;
2695  const section_size_type dynamic_size = dynamic_count * sym_size;
2696  const unsigned int first_dynamic_global_index =
2697    this->first_dynamic_global_index_;
2698  unsigned char* dynamic_view;
2699  if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2700    dynamic_view = NULL;
2701  else
2702    dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2703
2704  for (Symbol_table_type::const_iterator p = this->table_.begin();
2705       p != this->table_.end();
2706       ++p)
2707    {
2708      Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2709
2710      // Possibly warn about unresolved symbols in shared libraries.
2711      this->warn_about_undefined_dynobj_symbol(sym);
2712
2713      unsigned int sym_index = sym->symtab_index();
2714      unsigned int dynsym_index;
2715      if (dynamic_view == NULL)
2716	dynsym_index = -1U;
2717      else
2718	dynsym_index = sym->dynsym_index();
2719
2720      if (sym_index == -1U && dynsym_index == -1U)
2721	{
2722	  // This symbol is not included in the output file.
2723	  continue;
2724	}
2725
2726      unsigned int shndx;
2727      typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2728      typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2729      elfcpp::STB binding = sym->binding();
2730      switch (sym->source())
2731	{
2732	case Symbol::FROM_OBJECT:
2733	  {
2734	    bool is_ordinary;
2735	    unsigned int in_shndx = sym->shndx(&is_ordinary);
2736
2737	    if (!is_ordinary
2738		&& in_shndx != elfcpp::SHN_ABS
2739		&& !Symbol::is_common_shndx(in_shndx))
2740	      {
2741		gold_error(_("%s: unsupported symbol section 0x%x"),
2742			   sym->demangled_name().c_str(), in_shndx);
2743		shndx = in_shndx;
2744	      }
2745	    else
2746	      {
2747		Object* symobj = sym->object();
2748		if (symobj->is_dynamic())
2749		  {
2750		    if (sym->needs_dynsym_value())
2751		      dynsym_value = target.dynsym_value(sym);
2752		    shndx = elfcpp::SHN_UNDEF;
2753		    if (sym->is_undef_binding_weak())
2754		      binding = elfcpp::STB_WEAK;
2755		    else
2756		      binding = elfcpp::STB_GLOBAL;
2757		  }
2758		else if (symobj->pluginobj() != NULL)
2759		  shndx = elfcpp::SHN_UNDEF;
2760		else if (in_shndx == elfcpp::SHN_UNDEF
2761			 || (!is_ordinary
2762			     && (in_shndx == elfcpp::SHN_ABS
2763				 || Symbol::is_common_shndx(in_shndx))))
2764		  shndx = in_shndx;
2765		else
2766		  {
2767		    Relobj* relobj = static_cast<Relobj*>(symobj);
2768		    Output_section* os = relobj->output_section(in_shndx);
2769                    if (this->is_section_folded(relobj, in_shndx))
2770                      {
2771                        // This global symbol must be written out even though
2772                        // it is folded.
2773                        // Get the os of the section it is folded onto.
2774                        Section_id folded =
2775                             this->icf_->get_folded_section(relobj, in_shndx);
2776                        gold_assert(folded.first !=NULL);
2777                        Relobj* folded_obj =
2778                          reinterpret_cast<Relobj*>(folded.first);
2779                        os = folded_obj->output_section(folded.second);
2780                        gold_assert(os != NULL);
2781                      }
2782		    gold_assert(os != NULL);
2783		    shndx = os->out_shndx();
2784
2785		    if (shndx >= elfcpp::SHN_LORESERVE)
2786		      {
2787			if (sym_index != -1U)
2788			  symtab_xindex->add(sym_index, shndx);
2789			if (dynsym_index != -1U)
2790			  dynsym_xindex->add(dynsym_index, shndx);
2791			shndx = elfcpp::SHN_XINDEX;
2792		      }
2793
2794		    // In object files symbol values are section
2795		    // relative.
2796		    if (parameters->options().relocatable())
2797		      sym_value -= os->address();
2798		  }
2799	      }
2800	  }
2801	  break;
2802
2803	case Symbol::IN_OUTPUT_DATA:
2804	  shndx = sym->output_data()->out_shndx();
2805	  if (shndx >= elfcpp::SHN_LORESERVE)
2806	    {
2807	      if (sym_index != -1U)
2808		symtab_xindex->add(sym_index, shndx);
2809	      if (dynsym_index != -1U)
2810		dynsym_xindex->add(dynsym_index, shndx);
2811	      shndx = elfcpp::SHN_XINDEX;
2812	    }
2813	  break;
2814
2815	case Symbol::IN_OUTPUT_SEGMENT:
2816	  shndx = elfcpp::SHN_ABS;
2817	  break;
2818
2819	case Symbol::IS_CONSTANT:
2820	  shndx = elfcpp::SHN_ABS;
2821	  break;
2822
2823	case Symbol::IS_UNDEFINED:
2824	  shndx = elfcpp::SHN_UNDEF;
2825	  break;
2826
2827	default:
2828	  gold_unreachable();
2829	}
2830
2831      if (sym_index != -1U)
2832	{
2833	  sym_index -= first_global_index;
2834	  gold_assert(sym_index < output_count);
2835	  unsigned char* ps = psyms + (sym_index * sym_size);
2836	  this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2837						     binding, sympool, ps);
2838	}
2839
2840      if (dynsym_index != -1U)
2841	{
2842	  dynsym_index -= first_dynamic_global_index;
2843	  gold_assert(dynsym_index < dynamic_count);
2844	  unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2845	  this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2846						     binding, dynpool, pd);
2847	}
2848    }
2849
2850  of->write_output_view(this->offset_, oview_size, psyms);
2851  if (dynamic_view != NULL)
2852    of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2853}
2854
2855// Write out the symbol SYM, in section SHNDX, to P.  POOL is the
2856// strtab holding the name.
2857
2858template<int size, bool big_endian>
2859void
2860Symbol_table::sized_write_symbol(
2861    Sized_symbol<size>* sym,
2862    typename elfcpp::Elf_types<size>::Elf_Addr value,
2863    unsigned int shndx,
2864    elfcpp::STB binding,
2865    const Stringpool* pool,
2866    unsigned char* p) const
2867{
2868  elfcpp::Sym_write<size, big_endian> osym(p);
2869  osym.put_st_name(pool->get_offset(sym->name()));
2870  osym.put_st_value(value);
2871  // Use a symbol size of zero for undefined symbols from shared libraries.
2872  if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2873    osym.put_st_size(0);
2874  else
2875    osym.put_st_size(sym->symsize());
2876  elfcpp::STT type = sym->type();
2877  // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2878  if (type == elfcpp::STT_GNU_IFUNC
2879      && sym->is_from_dynobj())
2880    type = elfcpp::STT_FUNC;
2881  // A version script may have overridden the default binding.
2882  if (sym->is_forced_local())
2883    osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2884  else
2885    osym.put_st_info(elfcpp::elf_st_info(binding, type));
2886  osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2887  osym.put_st_shndx(shndx);
2888}
2889
2890// Check for unresolved symbols in shared libraries.  This is
2891// controlled by the --allow-shlib-undefined option.
2892
2893// We only warn about libraries for which we have seen all the
2894// DT_NEEDED entries.  We don't try to track down DT_NEEDED entries
2895// which were not seen in this link.  If we didn't see a DT_NEEDED
2896// entry, we aren't going to be able to reliably report whether the
2897// symbol is undefined.
2898
2899// We also don't warn about libraries found in a system library
2900// directory (e.g., /lib or /usr/lib); we assume that those libraries
2901// are OK.  This heuristic avoids problems on GNU/Linux, in which -ldl
2902// can have undefined references satisfied by ld-linux.so.
2903
2904inline void
2905Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2906{
2907  bool dummy;
2908  if (sym->source() == Symbol::FROM_OBJECT
2909      && sym->object()->is_dynamic()
2910      && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2911      && sym->binding() != elfcpp::STB_WEAK
2912      && !parameters->options().allow_shlib_undefined()
2913      && !parameters->target().is_defined_by_abi(sym)
2914      && !sym->object()->is_in_system_directory())
2915    {
2916      // A very ugly cast.
2917      Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2918      if (!dynobj->has_unknown_needed_entries())
2919        gold_undefined_symbol(sym);
2920    }
2921}
2922
2923// Write out a section symbol.  Return the update offset.
2924
2925void
2926Symbol_table::write_section_symbol(const Output_section* os,
2927				   Output_symtab_xindex* symtab_xindex,
2928				   Output_file* of,
2929				   off_t offset) const
2930{
2931  switch (parameters->size_and_endianness())
2932    {
2933#ifdef HAVE_TARGET_32_LITTLE
2934    case Parameters::TARGET_32_LITTLE:
2935      this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2936						  offset);
2937      break;
2938#endif
2939#ifdef HAVE_TARGET_32_BIG
2940    case Parameters::TARGET_32_BIG:
2941      this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2942						 offset);
2943      break;
2944#endif
2945#ifdef HAVE_TARGET_64_LITTLE
2946    case Parameters::TARGET_64_LITTLE:
2947      this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2948						  offset);
2949      break;
2950#endif
2951#ifdef HAVE_TARGET_64_BIG
2952    case Parameters::TARGET_64_BIG:
2953      this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2954						 offset);
2955      break;
2956#endif
2957    default:
2958      gold_unreachable();
2959    }
2960}
2961
2962// Write out a section symbol, specialized for size and endianness.
2963
2964template<int size, bool big_endian>
2965void
2966Symbol_table::sized_write_section_symbol(const Output_section* os,
2967					 Output_symtab_xindex* symtab_xindex,
2968					 Output_file* of,
2969					 off_t offset) const
2970{
2971  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2972
2973  unsigned char* pov = of->get_output_view(offset, sym_size);
2974
2975  elfcpp::Sym_write<size, big_endian> osym(pov);
2976  osym.put_st_name(0);
2977  if (parameters->options().relocatable())
2978    osym.put_st_value(0);
2979  else
2980    osym.put_st_value(os->address());
2981  osym.put_st_size(0);
2982  osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2983				       elfcpp::STT_SECTION));
2984  osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2985
2986  unsigned int shndx = os->out_shndx();
2987  if (shndx >= elfcpp::SHN_LORESERVE)
2988    {
2989      symtab_xindex->add(os->symtab_index(), shndx);
2990      shndx = elfcpp::SHN_XINDEX;
2991    }
2992  osym.put_st_shndx(shndx);
2993
2994  of->write_output_view(offset, sym_size, pov);
2995}
2996
2997// Print statistical information to stderr.  This is used for --stats.
2998
2999void
3000Symbol_table::print_stats() const
3001{
3002#if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
3003  fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
3004	  program_name, this->table_.size(), this->table_.bucket_count());
3005#else
3006  fprintf(stderr, _("%s: symbol table entries: %zu\n"),
3007	  program_name, this->table_.size());
3008#endif
3009  this->namepool_.print_stats("symbol table stringpool");
3010}
3011
3012// We check for ODR violations by looking for symbols with the same
3013// name for which the debugging information reports that they were
3014// defined in different source locations.  When comparing the source
3015// location, we consider instances with the same base filename to be
3016// the same.  This is because different object files/shared libraries
3017// can include the same header file using different paths, and
3018// different optimization settings can make the line number appear to
3019// be a couple lines off, and we don't want to report an ODR violation
3020// in those cases.
3021
3022// This struct is used to compare line information, as returned by
3023// Dwarf_line_info::one_addr2line.  It implements a < comparison
3024// operator used with std::set.
3025
3026struct Odr_violation_compare
3027{
3028  bool
3029  operator()(const std::string& s1, const std::string& s2) const
3030  {
3031    // Inputs should be of the form "dirname/filename:linenum" where
3032    // "dirname/" is optional.  We want to compare just the filename.
3033
3034    // Find the last '/' and ':' in each string.
3035    std::string::size_type s1begin = s1.rfind('/');
3036    std::string::size_type s2begin = s2.rfind('/');
3037    std::string::size_type s1end = s1.rfind(':');
3038    std::string::size_type s2end = s2.rfind(':');
3039    // If there was no '/' in a string, start at the beginning.
3040    if (s1begin == std::string::npos)
3041      s1begin = 0;
3042    if (s2begin == std::string::npos)
3043      s2begin = 0;
3044    // If the ':' appeared in the directory name, compare to the end
3045    // of the string.
3046    if (s1end < s1begin)
3047      s1end = s1.size();
3048    if (s2end < s2begin)
3049      s2end = s2.size();
3050    // Compare takes lengths, not end indices.
3051    return s1.compare(s1begin, s1end - s1begin,
3052		      s2, s2begin, s2end - s2begin) < 0;
3053  }
3054};
3055
3056// Check candidate_odr_violations_ to find symbols with the same name
3057// but apparently different definitions (different source-file/line-no).
3058
3059void
3060Symbol_table::detect_odr_violations(const Task* task,
3061				    const char* output_file_name) const
3062{
3063  for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3064       it != candidate_odr_violations_.end();
3065       ++it)
3066    {
3067      const char* symbol_name = it->first;
3068      // Maps from symbol location to a sample object file we found
3069      // that location in.  We use a sorted map so the location order
3070      // is deterministic, but we only store an arbitrary object file
3071      // to avoid copying lots of names.
3072      std::map<std::string, std::string, Odr_violation_compare> line_nums;
3073
3074      for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3075               locs = it->second.begin();
3076           locs != it->second.end();
3077           ++locs)
3078        {
3079	  // We need to lock the object in order to read it.  This
3080	  // means that we have to run in a singleton Task.  If we
3081	  // want to run this in a general Task for better
3082	  // performance, we will need one Task for object, plus
3083	  // appropriate locking to ensure that we don't conflict with
3084	  // other uses of the object.  Also note, one_addr2line is not
3085          // currently thread-safe.
3086	  Task_lock_obj<Object> tl(task, locs->object);
3087          // 16 is the size of the object-cache that one_addr2line should use.
3088          std::string lineno = Dwarf_line_info::one_addr2line(
3089              locs->object, locs->shndx, locs->offset, 16);
3090          if (!lineno.empty())
3091            {
3092              std::string& sample_object = line_nums[lineno];
3093              if (sample_object.empty())
3094                sample_object = locs->object->name();
3095            }
3096        }
3097
3098      if (line_nums.size() > 1)
3099        {
3100          gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3101                         "places (possible ODR violation):"),
3102                       output_file_name, demangle(symbol_name).c_str());
3103          for (std::map<std::string, std::string>::const_iterator it2 =
3104		 line_nums.begin();
3105	       it2 != line_nums.end();
3106	       ++it2)
3107            fprintf(stderr, _("  %s from %s\n"),
3108                    it2->first.c_str(), it2->second.c_str());
3109        }
3110    }
3111  // We only call one_addr2line() in this function, so we can clear its cache.
3112  Dwarf_line_info::clear_addr2line_cache();
3113}
3114
3115// Warnings functions.
3116
3117// Add a new warning.
3118
3119void
3120Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3121		      const std::string& warning)
3122{
3123  name = symtab->canonicalize_name(name);
3124  this->warnings_[name].set(obj, warning);
3125}
3126
3127// Look through the warnings and mark the symbols for which we should
3128// warn.  This is called during Layout::finalize when we know the
3129// sources for all the symbols.
3130
3131void
3132Warnings::note_warnings(Symbol_table* symtab)
3133{
3134  for (Warning_table::iterator p = this->warnings_.begin();
3135       p != this->warnings_.end();
3136       ++p)
3137    {
3138      Symbol* sym = symtab->lookup(p->first, NULL);
3139      if (sym != NULL
3140	  && sym->source() == Symbol::FROM_OBJECT
3141	  && sym->object() == p->second.object)
3142	sym->set_has_warning();
3143    }
3144}
3145
3146// Issue a warning.  This is called when we see a relocation against a
3147// symbol for which has a warning.
3148
3149template<int size, bool big_endian>
3150void
3151Warnings::issue_warning(const Symbol* sym,
3152			const Relocate_info<size, big_endian>* relinfo,
3153			size_t relnum, off_t reloffset) const
3154{
3155  gold_assert(sym->has_warning());
3156  Warning_table::const_iterator p = this->warnings_.find(sym->name());
3157  gold_assert(p != this->warnings_.end());
3158  gold_warning_at_location(relinfo, relnum, reloffset,
3159			   "%s", p->second.text.c_str());
3160}
3161
3162// Instantiate the templates we need.  We could use the configure
3163// script to restrict this to only the ones needed for implemented
3164// targets.
3165
3166#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3167template
3168void
3169Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3170#endif
3171
3172#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3173template
3174void
3175Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3176#endif
3177
3178#ifdef HAVE_TARGET_32_LITTLE
3179template
3180void
3181Symbol_table::add_from_relobj<32, false>(
3182    Sized_relobj<32, false>* relobj,
3183    const unsigned char* syms,
3184    size_t count,
3185    size_t symndx_offset,
3186    const char* sym_names,
3187    size_t sym_name_size,
3188    Sized_relobj<32, false>::Symbols* sympointers,
3189    size_t* defined);
3190#endif
3191
3192#ifdef HAVE_TARGET_32_BIG
3193template
3194void
3195Symbol_table::add_from_relobj<32, true>(
3196    Sized_relobj<32, true>* relobj,
3197    const unsigned char* syms,
3198    size_t count,
3199    size_t symndx_offset,
3200    const char* sym_names,
3201    size_t sym_name_size,
3202    Sized_relobj<32, true>::Symbols* sympointers,
3203    size_t* defined);
3204#endif
3205
3206#ifdef HAVE_TARGET_64_LITTLE
3207template
3208void
3209Symbol_table::add_from_relobj<64, false>(
3210    Sized_relobj<64, false>* relobj,
3211    const unsigned char* syms,
3212    size_t count,
3213    size_t symndx_offset,
3214    const char* sym_names,
3215    size_t sym_name_size,
3216    Sized_relobj<64, false>::Symbols* sympointers,
3217    size_t* defined);
3218#endif
3219
3220#ifdef HAVE_TARGET_64_BIG
3221template
3222void
3223Symbol_table::add_from_relobj<64, true>(
3224    Sized_relobj<64, true>* relobj,
3225    const unsigned char* syms,
3226    size_t count,
3227    size_t symndx_offset,
3228    const char* sym_names,
3229    size_t sym_name_size,
3230    Sized_relobj<64, true>::Symbols* sympointers,
3231    size_t* defined);
3232#endif
3233
3234#ifdef HAVE_TARGET_32_LITTLE
3235template
3236Symbol*
3237Symbol_table::add_from_pluginobj<32, false>(
3238    Sized_pluginobj<32, false>* obj,
3239    const char* name,
3240    const char* ver,
3241    elfcpp::Sym<32, false>* sym);
3242#endif
3243
3244#ifdef HAVE_TARGET_32_BIG
3245template
3246Symbol*
3247Symbol_table::add_from_pluginobj<32, true>(
3248    Sized_pluginobj<32, true>* obj,
3249    const char* name,
3250    const char* ver,
3251    elfcpp::Sym<32, true>* sym);
3252#endif
3253
3254#ifdef HAVE_TARGET_64_LITTLE
3255template
3256Symbol*
3257Symbol_table::add_from_pluginobj<64, false>(
3258    Sized_pluginobj<64, false>* obj,
3259    const char* name,
3260    const char* ver,
3261    elfcpp::Sym<64, false>* sym);
3262#endif
3263
3264#ifdef HAVE_TARGET_64_BIG
3265template
3266Symbol*
3267Symbol_table::add_from_pluginobj<64, true>(
3268    Sized_pluginobj<64, true>* obj,
3269    const char* name,
3270    const char* ver,
3271    elfcpp::Sym<64, true>* sym);
3272#endif
3273
3274#ifdef HAVE_TARGET_32_LITTLE
3275template
3276void
3277Symbol_table::add_from_dynobj<32, false>(
3278    Sized_dynobj<32, false>* dynobj,
3279    const unsigned char* syms,
3280    size_t count,
3281    const char* sym_names,
3282    size_t sym_name_size,
3283    const unsigned char* versym,
3284    size_t versym_size,
3285    const std::vector<const char*>* version_map,
3286    Sized_relobj<32, false>::Symbols* sympointers,
3287    size_t* defined);
3288#endif
3289
3290#ifdef HAVE_TARGET_32_BIG
3291template
3292void
3293Symbol_table::add_from_dynobj<32, true>(
3294    Sized_dynobj<32, true>* dynobj,
3295    const unsigned char* syms,
3296    size_t count,
3297    const char* sym_names,
3298    size_t sym_name_size,
3299    const unsigned char* versym,
3300    size_t versym_size,
3301    const std::vector<const char*>* version_map,
3302    Sized_relobj<32, true>::Symbols* sympointers,
3303    size_t* defined);
3304#endif
3305
3306#ifdef HAVE_TARGET_64_LITTLE
3307template
3308void
3309Symbol_table::add_from_dynobj<64, false>(
3310    Sized_dynobj<64, false>* dynobj,
3311    const unsigned char* syms,
3312    size_t count,
3313    const char* sym_names,
3314    size_t sym_name_size,
3315    const unsigned char* versym,
3316    size_t versym_size,
3317    const std::vector<const char*>* version_map,
3318    Sized_relobj<64, false>::Symbols* sympointers,
3319    size_t* defined);
3320#endif
3321
3322#ifdef HAVE_TARGET_64_BIG
3323template
3324void
3325Symbol_table::add_from_dynobj<64, true>(
3326    Sized_dynobj<64, true>* dynobj,
3327    const unsigned char* syms,
3328    size_t count,
3329    const char* sym_names,
3330    size_t sym_name_size,
3331    const unsigned char* versym,
3332    size_t versym_size,
3333    const std::vector<const char*>* version_map,
3334    Sized_relobj<64, true>::Symbols* sympointers,
3335    size_t* defined);
3336#endif
3337
3338#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3339template
3340void
3341Symbol_table::define_with_copy_reloc<32>(
3342    Sized_symbol<32>* sym,
3343    Output_data* posd,
3344    elfcpp::Elf_types<32>::Elf_Addr value);
3345#endif
3346
3347#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3348template
3349void
3350Symbol_table::define_with_copy_reloc<64>(
3351    Sized_symbol<64>* sym,
3352    Output_data* posd,
3353    elfcpp::Elf_types<64>::Elf_Addr value);
3354#endif
3355
3356#ifdef HAVE_TARGET_32_LITTLE
3357template
3358void
3359Warnings::issue_warning<32, false>(const Symbol* sym,
3360				   const Relocate_info<32, false>* relinfo,
3361				   size_t relnum, off_t reloffset) const;
3362#endif
3363
3364#ifdef HAVE_TARGET_32_BIG
3365template
3366void
3367Warnings::issue_warning<32, true>(const Symbol* sym,
3368				  const Relocate_info<32, true>* relinfo,
3369				  size_t relnum, off_t reloffset) const;
3370#endif
3371
3372#ifdef HAVE_TARGET_64_LITTLE
3373template
3374void
3375Warnings::issue_warning<64, false>(const Symbol* sym,
3376				   const Relocate_info<64, false>* relinfo,
3377				   size_t relnum, off_t reloffset) const;
3378#endif
3379
3380#ifdef HAVE_TARGET_64_BIG
3381template
3382void
3383Warnings::issue_warning<64, true>(const Symbol* sym,
3384				  const Relocate_info<64, true>* relinfo,
3385				  size_t relnum, off_t reloffset) const;
3386#endif
3387
3388} // End namespace gold.
3389