* plugin.cc (class Plugin_rescan): Define new class.
[deliverable/binutils-gdb.git] / gold / symtab.cc
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
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol. This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54 elfcpp::STT type, elfcpp::STB binding,
55 elfcpp::STV visibility, unsigned char nonvis)
56 {
57 this->name_ = name;
58 this->version_ = version;
59 this->symtab_index_ = 0;
60 this->dynsym_index_ = 0;
61 this->got_offsets_.init();
62 this->plt_offset_ = -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
86 static std::string
87 demangle(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
103 std::string
104 Symbol::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
111 template<int size, bool big_endian>
112 void
113 Symbol::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
131 void
132 Symbol::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
148 void
149 Symbol::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
166 void
167 Symbol::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
180 void
181 Symbol::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
194 void
195 Symbol::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
205 template<int size>
206 template<bool big_endian>
207 void
208 Sized_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
221 template<int size>
222 void
223 Sized_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
240 template<int size>
241 void
242 Sized_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
259 template<int size>
260 void
261 Sized_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
273 template<int size>
274 void
275 Sized_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
286 bool
287 Symbol::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
296 template<int size>
297 void
298 Sized_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
310 inline bool
311 Symbol::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
394 bool
395 Symbol::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
432 Output_section*
433 Symbol::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
467 void
468 Symbol::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
490 Symbol_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
500 Symbol_table::~Symbol_table()
501 {
502 }
503
504 // The symbol table key equality function. This is called with
505 // Stringpool keys.
506
507 inline bool
508 Symbol_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
514 bool
515 Symbol_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
524 void
525 Symbol_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
571 void
572 Symbol_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.
591 inline void
592 Symbol_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
610 void
611 Symbol_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
621 Symbol*
622 Symbol_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
633 Symbol*
634 Symbol_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
662 template<int size, bool big_endian>
663 void
664 Symbol_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
688 void
689 Symbol_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
706 const char*
707 Symbol_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
755 template<int size, bool big_endian>
756 void
757 Symbol_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
855 template<int size, bool big_endian>
856 Sized_symbol<size>*
857 Symbol_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
1042 template<int size, bool big_endian>
1043 void
1044 Symbol_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
1226 template<int size, bool big_endian>
1227 Symbol*
1228 Symbol_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
1290 template<int size, bool big_endian>
1291 void
1292 Symbol_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
1486 template<int size>
1487 class Weak_alias_sorter
1488 {
1489 public:
1490 bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1491 };
1492
1493 template<int size>
1494 bool
1495 Weak_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
1523 template<int size>
1524 void
1525 Symbol_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
1575 template<int size, bool big_endian>
1576 Sized_symbol<size>*
1577 Symbol_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
1720 Symbol*
1721 Symbol_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
1764 template<int size>
1765 Sized_symbol<size>*
1766 Symbol_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
1835 Symbol*
1836 Symbol_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
1877 template<int size>
1878 Sized_symbol<size>*
1879 Symbol_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
1949 Symbol*
1950 Symbol_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
1990 template<int size>
1991 Sized_symbol<size>*
1992 Symbol_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
2067 void
2068 Symbol_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
2091 void
2092 Symbol_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
2119 template<int size>
2120 void
2121 Symbol_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
2170 Dynobj*
2171 Symbol_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
2182 void
2183 Symbol_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
2209 template<int size>
2210 void
2211 Symbol_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
2226 template<int size>
2227 void
2228 Symbol_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
2271 unsigned int
2272 Symbol_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
2320 off_t
2321 Symbol_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
2363 template<int size>
2364 void
2365 Symbol_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
2378 template<int size>
2379 off_t
2380 Symbol_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
2423 template<int size>
2424 typename Sized_symbol<size>::Value_type
2425 Symbol_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
2575 template<int size>
2576 bool
2577 Symbol_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
2633 void
2634 Symbol_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
2673 template<int size, bool big_endian>
2674 void
2675 Symbol_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
2858 template<int size, bool big_endian>
2859 void
2860 Symbol_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
2904 inline void
2905 Symbol_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
2925 void
2926 Symbol_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
2964 template<int size, bool big_endian>
2965 void
2966 Symbol_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
2999 void
3000 Symbol_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 and
3016 // line number to be the same. This is because different object
3017 // files/shared libraries can include the same header file using
3018 // different paths, and we don't want to report an ODR violation in
3019 // that case.
3020
3021 // This struct is used to compare line information, as returned by
3022 // Dwarf_line_info::one_addr2line. It implements a < comparison
3023 // operator used with std::set.
3024
3025 struct Odr_violation_compare
3026 {
3027 bool
3028 operator()(const std::string& s1, const std::string& s2) const
3029 {
3030 std::string::size_type pos1 = s1.rfind('/');
3031 std::string::size_type pos2 = s2.rfind('/');
3032 if (pos1 == std::string::npos
3033 || pos2 == std::string::npos)
3034 return s1 < s2;
3035 return s1.compare(pos1, std::string::npos,
3036 s2, pos2, std::string::npos) < 0;
3037 }
3038 };
3039
3040 // Check candidate_odr_violations_ to find symbols with the same name
3041 // but apparently different definitions (different source-file/line-no).
3042
3043 void
3044 Symbol_table::detect_odr_violations(const Task* task,
3045 const char* output_file_name) const
3046 {
3047 for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
3048 it != candidate_odr_violations_.end();
3049 ++it)
3050 {
3051 const char* symbol_name = it->first;
3052 // Maps from symbol location to a sample object file we found
3053 // that location in. We use a sorted map so the location order
3054 // is deterministic, but we only store an arbitrary object file
3055 // to avoid copying lots of names.
3056 std::map<std::string, std::string, Odr_violation_compare> line_nums;
3057
3058 for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3059 locs = it->second.begin();
3060 locs != it->second.end();
3061 ++locs)
3062 {
3063 // We need to lock the object in order to read it. This
3064 // means that we have to run in a singleton Task. If we
3065 // want to run this in a general Task for better
3066 // performance, we will need one Task for object, plus
3067 // appropriate locking to ensure that we don't conflict with
3068 // other uses of the object. Also note, one_addr2line is not
3069 // currently thread-safe.
3070 Task_lock_obj<Object> tl(task, locs->object);
3071 // 16 is the size of the object-cache that one_addr2line should use.
3072 std::string lineno = Dwarf_line_info::one_addr2line(
3073 locs->object, locs->shndx, locs->offset, 16);
3074 if (!lineno.empty())
3075 {
3076 std::string& sample_object = line_nums[lineno];
3077 if (sample_object.empty())
3078 sample_object = locs->object->name();
3079 }
3080 }
3081
3082 if (line_nums.size() > 1)
3083 {
3084 gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3085 "places (possible ODR violation):"),
3086 output_file_name, demangle(symbol_name).c_str());
3087 for (std::map<std::string, std::string>::const_iterator it2 =
3088 line_nums.begin();
3089 it2 != line_nums.end();
3090 ++it2)
3091 fprintf(stderr, _(" %s from %s\n"),
3092 it2->first.c_str(), it2->second.c_str());
3093 }
3094 }
3095 // We only call one_addr2line() in this function, so we can clear its cache.
3096 Dwarf_line_info::clear_addr2line_cache();
3097 }
3098
3099 // Warnings functions.
3100
3101 // Add a new warning.
3102
3103 void
3104 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3105 const std::string& warning)
3106 {
3107 name = symtab->canonicalize_name(name);
3108 this->warnings_[name].set(obj, warning);
3109 }
3110
3111 // Look through the warnings and mark the symbols for which we should
3112 // warn. This is called during Layout::finalize when we know the
3113 // sources for all the symbols.
3114
3115 void
3116 Warnings::note_warnings(Symbol_table* symtab)
3117 {
3118 for (Warning_table::iterator p = this->warnings_.begin();
3119 p != this->warnings_.end();
3120 ++p)
3121 {
3122 Symbol* sym = symtab->lookup(p->first, NULL);
3123 if (sym != NULL
3124 && sym->source() == Symbol::FROM_OBJECT
3125 && sym->object() == p->second.object)
3126 sym->set_has_warning();
3127 }
3128 }
3129
3130 // Issue a warning. This is called when we see a relocation against a
3131 // symbol for which has a warning.
3132
3133 template<int size, bool big_endian>
3134 void
3135 Warnings::issue_warning(const Symbol* sym,
3136 const Relocate_info<size, big_endian>* relinfo,
3137 size_t relnum, off_t reloffset) const
3138 {
3139 gold_assert(sym->has_warning());
3140 Warning_table::const_iterator p = this->warnings_.find(sym->name());
3141 gold_assert(p != this->warnings_.end());
3142 gold_warning_at_location(relinfo, relnum, reloffset,
3143 "%s", p->second.text.c_str());
3144 }
3145
3146 // Instantiate the templates we need. We could use the configure
3147 // script to restrict this to only the ones needed for implemented
3148 // targets.
3149
3150 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3151 template
3152 void
3153 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3154 #endif
3155
3156 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3157 template
3158 void
3159 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3160 #endif
3161
3162 #ifdef HAVE_TARGET_32_LITTLE
3163 template
3164 void
3165 Symbol_table::add_from_relobj<32, false>(
3166 Sized_relobj<32, false>* relobj,
3167 const unsigned char* syms,
3168 size_t count,
3169 size_t symndx_offset,
3170 const char* sym_names,
3171 size_t sym_name_size,
3172 Sized_relobj<32, false>::Symbols* sympointers,
3173 size_t* defined);
3174 #endif
3175
3176 #ifdef HAVE_TARGET_32_BIG
3177 template
3178 void
3179 Symbol_table::add_from_relobj<32, true>(
3180 Sized_relobj<32, true>* relobj,
3181 const unsigned char* syms,
3182 size_t count,
3183 size_t symndx_offset,
3184 const char* sym_names,
3185 size_t sym_name_size,
3186 Sized_relobj<32, true>::Symbols* sympointers,
3187 size_t* defined);
3188 #endif
3189
3190 #ifdef HAVE_TARGET_64_LITTLE
3191 template
3192 void
3193 Symbol_table::add_from_relobj<64, false>(
3194 Sized_relobj<64, false>* relobj,
3195 const unsigned char* syms,
3196 size_t count,
3197 size_t symndx_offset,
3198 const char* sym_names,
3199 size_t sym_name_size,
3200 Sized_relobj<64, false>::Symbols* sympointers,
3201 size_t* defined);
3202 #endif
3203
3204 #ifdef HAVE_TARGET_64_BIG
3205 template
3206 void
3207 Symbol_table::add_from_relobj<64, true>(
3208 Sized_relobj<64, true>* relobj,
3209 const unsigned char* syms,
3210 size_t count,
3211 size_t symndx_offset,
3212 const char* sym_names,
3213 size_t sym_name_size,
3214 Sized_relobj<64, true>::Symbols* sympointers,
3215 size_t* defined);
3216 #endif
3217
3218 #ifdef HAVE_TARGET_32_LITTLE
3219 template
3220 Symbol*
3221 Symbol_table::add_from_pluginobj<32, false>(
3222 Sized_pluginobj<32, false>* obj,
3223 const char* name,
3224 const char* ver,
3225 elfcpp::Sym<32, false>* sym);
3226 #endif
3227
3228 #ifdef HAVE_TARGET_32_BIG
3229 template
3230 Symbol*
3231 Symbol_table::add_from_pluginobj<32, true>(
3232 Sized_pluginobj<32, true>* obj,
3233 const char* name,
3234 const char* ver,
3235 elfcpp::Sym<32, true>* sym);
3236 #endif
3237
3238 #ifdef HAVE_TARGET_64_LITTLE
3239 template
3240 Symbol*
3241 Symbol_table::add_from_pluginobj<64, false>(
3242 Sized_pluginobj<64, false>* obj,
3243 const char* name,
3244 const char* ver,
3245 elfcpp::Sym<64, false>* sym);
3246 #endif
3247
3248 #ifdef HAVE_TARGET_64_BIG
3249 template
3250 Symbol*
3251 Symbol_table::add_from_pluginobj<64, true>(
3252 Sized_pluginobj<64, true>* obj,
3253 const char* name,
3254 const char* ver,
3255 elfcpp::Sym<64, true>* sym);
3256 #endif
3257
3258 #ifdef HAVE_TARGET_32_LITTLE
3259 template
3260 void
3261 Symbol_table::add_from_dynobj<32, false>(
3262 Sized_dynobj<32, false>* dynobj,
3263 const unsigned char* syms,
3264 size_t count,
3265 const char* sym_names,
3266 size_t sym_name_size,
3267 const unsigned char* versym,
3268 size_t versym_size,
3269 const std::vector<const char*>* version_map,
3270 Sized_relobj<32, false>::Symbols* sympointers,
3271 size_t* defined);
3272 #endif
3273
3274 #ifdef HAVE_TARGET_32_BIG
3275 template
3276 void
3277 Symbol_table::add_from_dynobj<32, true>(
3278 Sized_dynobj<32, true>* 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, true>::Symbols* sympointers,
3287 size_t* defined);
3288 #endif
3289
3290 #ifdef HAVE_TARGET_64_LITTLE
3291 template
3292 void
3293 Symbol_table::add_from_dynobj<64, false>(
3294 Sized_dynobj<64, false>* 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<64, false>::Symbols* sympointers,
3303 size_t* defined);
3304 #endif
3305
3306 #ifdef HAVE_TARGET_64_BIG
3307 template
3308 void
3309 Symbol_table::add_from_dynobj<64, true>(
3310 Sized_dynobj<64, true>* 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, true>::Symbols* sympointers,
3319 size_t* defined);
3320 #endif
3321
3322 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3323 template
3324 void
3325 Symbol_table::define_with_copy_reloc<32>(
3326 Sized_symbol<32>* sym,
3327 Output_data* posd,
3328 elfcpp::Elf_types<32>::Elf_Addr value);
3329 #endif
3330
3331 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3332 template
3333 void
3334 Symbol_table::define_with_copy_reloc<64>(
3335 Sized_symbol<64>* sym,
3336 Output_data* posd,
3337 elfcpp::Elf_types<64>::Elf_Addr value);
3338 #endif
3339
3340 #ifdef HAVE_TARGET_32_LITTLE
3341 template
3342 void
3343 Warnings::issue_warning<32, false>(const Symbol* sym,
3344 const Relocate_info<32, false>* relinfo,
3345 size_t relnum, off_t reloffset) const;
3346 #endif
3347
3348 #ifdef HAVE_TARGET_32_BIG
3349 template
3350 void
3351 Warnings::issue_warning<32, true>(const Symbol* sym,
3352 const Relocate_info<32, true>* relinfo,
3353 size_t relnum, off_t reloffset) const;
3354 #endif
3355
3356 #ifdef HAVE_TARGET_64_LITTLE
3357 template
3358 void
3359 Warnings::issue_warning<64, false>(const Symbol* sym,
3360 const Relocate_info<64, false>* relinfo,
3361 size_t relnum, off_t reloffset) const;
3362 #endif
3363
3364 #ifdef HAVE_TARGET_64_BIG
3365 template
3366 void
3367 Warnings::issue_warning<64, true>(const Symbol* sym,
3368 const Relocate_info<64, true>* relinfo,
3369 size_t relnum, off_t reloffset) const;
3370 #endif
3371
3372 } // End namespace gold.
This page took 0.09397 seconds and 5 git commands to generate.