PR 10916
[deliverable/binutils-gdb.git] / gold / symtab.cc
1 // symtab.cc -- the gold symbol table
2
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
32
33 #include "gc.h"
34 #include "object.h"
35 #include "dwarf_reader.h"
36 #include "dynobj.h"
37 #include "output.h"
38 #include "target.h"
39 #include "workqueue.h"
40 #include "symtab.h"
41 #include "demangle.h" // needed for --dynamic-list-cpp-new
42 #include "plugin.h"
43
44 namespace gold
45 {
46
47 // Class Symbol.
48
49 // Initialize fields in Symbol. This initializes everything except u_
50 // and source_.
51
52 void
53 Symbol::init_fields(const char* name, const char* version,
54 elfcpp::STT type, elfcpp::STB binding,
55 elfcpp::STV visibility, unsigned char nonvis)
56 {
57 this->name_ = name;
58 this->version_ = version;
59 this->symtab_index_ = 0;
60 this->dynsym_index_ = 0;
61 this->got_offsets_.init();
62 this->plt_offset_ = 0;
63 this->type_ = type;
64 this->binding_ = binding;
65 this->visibility_ = visibility;
66 this->nonvis_ = nonvis;
67 this->is_target_special_ = false;
68 this->is_def_ = false;
69 this->is_forwarder_ = false;
70 this->has_alias_ = false;
71 this->needs_dynsym_entry_ = false;
72 this->in_reg_ = false;
73 this->in_dyn_ = false;
74 this->has_plt_offset_ = false;
75 this->has_warning_ = false;
76 this->is_copied_from_dynobj_ = false;
77 this->is_forced_local_ = false;
78 this->is_ordinary_shndx_ = false;
79 this->in_real_elf_ = false;
80 }
81
82 // Return the demangled version of the symbol's name, but only
83 // if the --demangle flag was set.
84
85 static std::string
86 demangle(const char* name)
87 {
88 if (!parameters->options().do_demangle())
89 return name;
90
91 // cplus_demangle allocates memory for the result it returns,
92 // and returns NULL if the name is already demangled.
93 char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
94 if (demangled_name == NULL)
95 return name;
96
97 std::string retval(demangled_name);
98 free(demangled_name);
99 return retval;
100 }
101
102 std::string
103 Symbol::demangled_name() const
104 {
105 return demangle(this->name());
106 }
107
108 // Initialize the fields in the base class Symbol for SYM in OBJECT.
109
110 template<int size, bool big_endian>
111 void
112 Symbol::init_base_object(const char* name, const char* version, Object* object,
113 const elfcpp::Sym<size, big_endian>& sym,
114 unsigned int st_shndx, bool is_ordinary)
115 {
116 this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
117 sym.get_st_visibility(), sym.get_st_nonvis());
118 this->u_.from_object.object = object;
119 this->u_.from_object.shndx = st_shndx;
120 this->is_ordinary_shndx_ = is_ordinary;
121 this->source_ = FROM_OBJECT;
122 this->in_reg_ = !object->is_dynamic();
123 this->in_dyn_ = object->is_dynamic();
124 this->in_real_elf_ = object->pluginobj() == NULL;
125 }
126
127 // Initialize the fields in the base class Symbol for a symbol defined
128 // in an Output_data.
129
130 void
131 Symbol::init_base_output_data(const char* name, const char* version,
132 Output_data* od, elfcpp::STT type,
133 elfcpp::STB binding, elfcpp::STV visibility,
134 unsigned char nonvis, bool offset_is_from_end)
135 {
136 this->init_fields(name, version, type, binding, visibility, nonvis);
137 this->u_.in_output_data.output_data = od;
138 this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
139 this->source_ = IN_OUTPUT_DATA;
140 this->in_reg_ = true;
141 this->in_real_elf_ = true;
142 }
143
144 // Initialize the fields in the base class Symbol for a symbol defined
145 // in an Output_segment.
146
147 void
148 Symbol::init_base_output_segment(const char* name, const char* version,
149 Output_segment* os, elfcpp::STT type,
150 elfcpp::STB binding, elfcpp::STV visibility,
151 unsigned char nonvis,
152 Segment_offset_base offset_base)
153 {
154 this->init_fields(name, version, type, binding, visibility, nonvis);
155 this->u_.in_output_segment.output_segment = os;
156 this->u_.in_output_segment.offset_base = offset_base;
157 this->source_ = IN_OUTPUT_SEGMENT;
158 this->in_reg_ = true;
159 this->in_real_elf_ = true;
160 }
161
162 // Initialize the fields in the base class Symbol for a symbol defined
163 // as a constant.
164
165 void
166 Symbol::init_base_constant(const char* name, const char* version,
167 elfcpp::STT type, elfcpp::STB binding,
168 elfcpp::STV visibility, unsigned char nonvis)
169 {
170 this->init_fields(name, version, type, binding, visibility, nonvis);
171 this->source_ = IS_CONSTANT;
172 this->in_reg_ = true;
173 this->in_real_elf_ = true;
174 }
175
176 // Initialize the fields in the base class Symbol for an undefined
177 // symbol.
178
179 void
180 Symbol::init_base_undefined(const char* name, const char* version,
181 elfcpp::STT type, elfcpp::STB binding,
182 elfcpp::STV visibility, unsigned char nonvis)
183 {
184 this->init_fields(name, version, type, binding, visibility, nonvis);
185 this->dynsym_index_ = -1U;
186 this->source_ = IS_UNDEFINED;
187 this->in_reg_ = true;
188 this->in_real_elf_ = true;
189 }
190
191 // Allocate a common symbol in the base.
192
193 void
194 Symbol::allocate_base_common(Output_data* od)
195 {
196 gold_assert(this->is_common());
197 this->source_ = IN_OUTPUT_DATA;
198 this->u_.in_output_data.output_data = od;
199 this->u_.in_output_data.offset_is_from_end = false;
200 }
201
202 // Initialize the fields in Sized_symbol for SYM in OBJECT.
203
204 template<int size>
205 template<bool big_endian>
206 void
207 Sized_symbol<size>::init_object(const char* name, const char* version,
208 Object* object,
209 const elfcpp::Sym<size, big_endian>& sym,
210 unsigned int st_shndx, bool is_ordinary)
211 {
212 this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
213 this->value_ = sym.get_st_value();
214 this->symsize_ = sym.get_st_size();
215 }
216
217 // Initialize the fields in Sized_symbol for a symbol defined in an
218 // Output_data.
219
220 template<int size>
221 void
222 Sized_symbol<size>::init_output_data(const char* name, const char* version,
223 Output_data* od, Value_type value,
224 Size_type symsize, elfcpp::STT type,
225 elfcpp::STB binding,
226 elfcpp::STV visibility,
227 unsigned char nonvis,
228 bool offset_is_from_end)
229 {
230 this->init_base_output_data(name, version, od, type, binding, visibility,
231 nonvis, offset_is_from_end);
232 this->value_ = value;
233 this->symsize_ = symsize;
234 }
235
236 // Initialize the fields in Sized_symbol for a symbol defined in an
237 // Output_segment.
238
239 template<int size>
240 void
241 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
242 Output_segment* os, Value_type value,
243 Size_type symsize, elfcpp::STT type,
244 elfcpp::STB binding,
245 elfcpp::STV visibility,
246 unsigned char nonvis,
247 Segment_offset_base offset_base)
248 {
249 this->init_base_output_segment(name, version, os, type, binding, visibility,
250 nonvis, offset_base);
251 this->value_ = value;
252 this->symsize_ = symsize;
253 }
254
255 // Initialize the fields in Sized_symbol for a symbol defined as a
256 // constant.
257
258 template<int size>
259 void
260 Sized_symbol<size>::init_constant(const char* name, const char* version,
261 Value_type value, Size_type symsize,
262 elfcpp::STT type, elfcpp::STB binding,
263 elfcpp::STV visibility, unsigned char nonvis)
264 {
265 this->init_base_constant(name, version, type, binding, visibility, nonvis);
266 this->value_ = value;
267 this->symsize_ = symsize;
268 }
269
270 // Initialize the fields in Sized_symbol for an undefined symbol.
271
272 template<int size>
273 void
274 Sized_symbol<size>::init_undefined(const char* name, const char* version,
275 elfcpp::STT type, elfcpp::STB binding,
276 elfcpp::STV visibility, unsigned char nonvis)
277 {
278 this->init_base_undefined(name, version, type, binding, visibility, nonvis);
279 this->value_ = 0;
280 this->symsize_ = 0;
281 }
282
283 // Return true if SHNDX represents a common symbol.
284
285 bool
286 Symbol::is_common_shndx(unsigned int shndx)
287 {
288 return (shndx == elfcpp::SHN_COMMON
289 || shndx == parameters->target().small_common_shndx()
290 || shndx == parameters->target().large_common_shndx());
291 }
292
293 // Allocate a common symbol.
294
295 template<int size>
296 void
297 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
298 {
299 this->allocate_base_common(od);
300 this->value_ = value;
301 }
302
303 // The ""'s around str ensure str is a string literal, so sizeof works.
304 #define strprefix(var, str) (strncmp(var, str, sizeof("" str "") - 1) == 0)
305
306 // Return true if this symbol should be added to the dynamic symbol
307 // table.
308
309 inline bool
310 Symbol::should_add_dynsym_entry() const
311 {
312 // If the symbol is used by a dynamic relocation, we need to add it.
313 if (this->needs_dynsym_entry())
314 return true;
315
316 // If this symbol's section is not added, the symbol need not be added.
317 // The section may have been GCed. Note that export_dynamic is being
318 // overridden here. This should not be done for shared objects.
319 if (parameters->options().gc_sections()
320 && !parameters->options().shared()
321 && this->source() == Symbol::FROM_OBJECT
322 && !this->object()->is_dynamic())
323 {
324 Relobj* relobj = static_cast<Relobj*>(this->object());
325 bool is_ordinary;
326 unsigned int shndx = this->shndx(&is_ordinary);
327 if (is_ordinary && shndx != elfcpp::SHN_UNDEF
328 && !relobj->is_section_included(shndx))
329 return false;
330 }
331
332 // If the symbol was forced local in a version script, do not add it.
333 if (this->is_forced_local())
334 return false;
335
336 // If the symbol was forced dynamic in a --dynamic-list file, add it.
337 if (parameters->options().in_dynamic_list(this->name()))
338 return true;
339
340 // If dynamic-list-data was specified, add any STT_OBJECT.
341 if (parameters->options().dynamic_list_data()
342 && !this->is_from_dynobj()
343 && this->type() == elfcpp::STT_OBJECT)
344 return true;
345
346 // If --dynamic-list-cpp-new was specified, add any new/delete symbol.
347 // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols.
348 if ((parameters->options().dynamic_list_cpp_new()
349 || parameters->options().dynamic_list_cpp_typeinfo())
350 && !this->is_from_dynobj())
351 {
352 // TODO(csilvers): We could probably figure out if we're an operator
353 // new/delete or typeinfo without the need to demangle.
354 char* demangled_name = cplus_demangle(this->name(),
355 DMGL_ANSI | DMGL_PARAMS);
356 if (demangled_name == NULL)
357 {
358 // Not a C++ symbol, so it can't satisfy these flags
359 }
360 else if (parameters->options().dynamic_list_cpp_new()
361 && (strprefix(demangled_name, "operator new")
362 || strprefix(demangled_name, "operator delete")))
363 {
364 free(demangled_name);
365 return true;
366 }
367 else if (parameters->options().dynamic_list_cpp_typeinfo()
368 && (strprefix(demangled_name, "typeinfo name for")
369 || strprefix(demangled_name, "typeinfo for")))
370 {
371 free(demangled_name);
372 return true;
373 }
374 else
375 free(demangled_name);
376 }
377
378 // If exporting all symbols or building a shared library,
379 // and the symbol is defined in a regular object and is
380 // externally visible, we need to add it.
381 if ((parameters->options().export_dynamic() || parameters->options().shared())
382 && !this->is_from_dynobj()
383 && this->is_externally_visible())
384 return true;
385
386 return false;
387 }
388
389 // Return true if the final value of this symbol is known at link
390 // time.
391
392 bool
393 Symbol::final_value_is_known() const
394 {
395 // If we are not generating an executable, then no final values are
396 // known, since they will change at runtime.
397 if (parameters->options().output_is_position_independent()
398 || parameters->options().relocatable())
399 return false;
400
401 // If the symbol is not from an object file, and is not undefined,
402 // then it is defined, and known.
403 if (this->source_ != FROM_OBJECT)
404 {
405 if (this->source_ != IS_UNDEFINED)
406 return true;
407 }
408 else
409 {
410 // If the symbol is from a dynamic object, then the final value
411 // is not known.
412 if (this->object()->is_dynamic())
413 return false;
414
415 // If the symbol is not undefined (it is defined or common),
416 // then the final value is known.
417 if (!this->is_undefined())
418 return true;
419 }
420
421 // If the symbol is undefined, then whether the final value is known
422 // depends on whether we are doing a static link. If we are doing a
423 // dynamic link, then the final value could be filled in at runtime.
424 // This could reasonably be the case for a weak undefined symbol.
425 return parameters->doing_static_link();
426 }
427
428 // Return the output section where this symbol is defined.
429
430 Output_section*
431 Symbol::output_section() const
432 {
433 switch (this->source_)
434 {
435 case FROM_OBJECT:
436 {
437 unsigned int shndx = this->u_.from_object.shndx;
438 if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
439 {
440 gold_assert(!this->u_.from_object.object->is_dynamic());
441 gold_assert(this->u_.from_object.object->pluginobj() == NULL);
442 Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
443 return relobj->output_section(shndx);
444 }
445 return NULL;
446 }
447
448 case IN_OUTPUT_DATA:
449 return this->u_.in_output_data.output_data->output_section();
450
451 case IN_OUTPUT_SEGMENT:
452 case IS_CONSTANT:
453 case IS_UNDEFINED:
454 return NULL;
455
456 default:
457 gold_unreachable();
458 }
459 }
460
461 // Set the symbol's output section. This is used for symbols defined
462 // in scripts. This should only be called after the symbol table has
463 // been finalized.
464
465 void
466 Symbol::set_output_section(Output_section* os)
467 {
468 switch (this->source_)
469 {
470 case FROM_OBJECT:
471 case IN_OUTPUT_DATA:
472 gold_assert(this->output_section() == os);
473 break;
474 case IS_CONSTANT:
475 this->source_ = IN_OUTPUT_DATA;
476 this->u_.in_output_data.output_data = os;
477 this->u_.in_output_data.offset_is_from_end = false;
478 break;
479 case IN_OUTPUT_SEGMENT:
480 case IS_UNDEFINED:
481 default:
482 gold_unreachable();
483 }
484 }
485
486 // Class Symbol_table.
487
488 Symbol_table::Symbol_table(unsigned int count,
489 const Version_script_info& version_script)
490 : saw_undefined_(0), offset_(0), table_(count), namepool_(),
491 forwarders_(), commons_(), tls_commons_(), small_commons_(),
492 large_commons_(), forced_locals_(), warnings_(),
493 version_script_(version_script), gc_(NULL), icf_(NULL)
494 {
495 namepool_.reserve(count);
496 }
497
498 Symbol_table::~Symbol_table()
499 {
500 }
501
502 // The hash function. The key values are Stringpool keys.
503
504 inline size_t
505 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
506 {
507 return key.first ^ key.second;
508 }
509
510 // The symbol table key equality function. This is called with
511 // Stringpool keys.
512
513 inline bool
514 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
515 const Symbol_table_key& k2) const
516 {
517 return k1.first == k2.first && k1.second == k2.second;
518 }
519
520 bool
521 Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const
522 {
523 return (parameters->options().icf_enabled()
524 && this->icf_->is_section_folded(obj, shndx));
525 }
526
527 // For symbols that have been listed with -u option, add them to the
528 // work list to avoid gc'ing them.
529
530 void
531 Symbol_table::gc_mark_undef_symbols()
532 {
533 for (options::String_set::const_iterator p =
534 parameters->options().undefined_begin();
535 p != parameters->options().undefined_end();
536 ++p)
537 {
538 const char* name = p->c_str();
539 Symbol* sym = this->lookup(name);
540 gold_assert (sym != NULL);
541 if (sym->source() == Symbol::FROM_OBJECT
542 && !sym->object()->is_dynamic())
543 {
544 Relobj* obj = static_cast<Relobj*>(sym->object());
545 bool is_ordinary;
546 unsigned int shndx = sym->shndx(&is_ordinary);
547 if (is_ordinary)
548 {
549 gold_assert(this->gc_ != NULL);
550 this->gc_->worklist().push(Section_id(obj, shndx));
551 }
552 }
553 }
554 }
555
556 void
557 Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym)
558 {
559 if (!sym->is_from_dynobj()
560 && sym->is_externally_visible())
561 {
562 //Add the object and section to the work list.
563 Relobj* obj = static_cast<Relobj*>(sym->object());
564 bool is_ordinary;
565 unsigned int shndx = sym->shndx(&is_ordinary);
566 if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
567 {
568 gold_assert(this->gc_!= NULL);
569 this->gc_->worklist().push(Section_id(obj, shndx));
570 }
571 }
572 }
573
574 // When doing garbage collection, keep symbols that have been seen in
575 // dynamic objects.
576 inline void
577 Symbol_table::gc_mark_dyn_syms(Symbol* sym)
578 {
579 if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT
580 && !sym->object()->is_dynamic())
581 {
582 Relobj *obj = static_cast<Relobj*>(sym->object());
583 bool is_ordinary;
584 unsigned int shndx = sym->shndx(&is_ordinary);
585 if (is_ordinary && shndx != elfcpp::SHN_UNDEF)
586 {
587 gold_assert(this->gc_ != NULL);
588 this->gc_->worklist().push(Section_id(obj, shndx));
589 }
590 }
591 }
592
593 // Make TO a symbol which forwards to FROM.
594
595 void
596 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
597 {
598 gold_assert(from != to);
599 gold_assert(!from->is_forwarder() && !to->is_forwarder());
600 this->forwarders_[from] = to;
601 from->set_forwarder();
602 }
603
604 // Resolve the forwards from FROM, returning the real symbol.
605
606 Symbol*
607 Symbol_table::resolve_forwards(const Symbol* from) const
608 {
609 gold_assert(from->is_forwarder());
610 Unordered_map<const Symbol*, Symbol*>::const_iterator p =
611 this->forwarders_.find(from);
612 gold_assert(p != this->forwarders_.end());
613 return p->second;
614 }
615
616 // Look up a symbol by name.
617
618 Symbol*
619 Symbol_table::lookup(const char* name, const char* version) const
620 {
621 Stringpool::Key name_key;
622 name = this->namepool_.find(name, &name_key);
623 if (name == NULL)
624 return NULL;
625
626 Stringpool::Key version_key = 0;
627 if (version != NULL)
628 {
629 version = this->namepool_.find(version, &version_key);
630 if (version == NULL)
631 return NULL;
632 }
633
634 Symbol_table_key key(name_key, version_key);
635 Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
636 if (p == this->table_.end())
637 return NULL;
638 return p->second;
639 }
640
641 // Resolve a Symbol with another Symbol. This is only used in the
642 // unusual case where there are references to both an unversioned
643 // symbol and a symbol with a version, and we then discover that that
644 // version is the default version. Because this is unusual, we do
645 // this the slow way, by converting back to an ELF symbol.
646
647 template<int size, bool big_endian>
648 void
649 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from)
650 {
651 unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
652 elfcpp::Sym_write<size, big_endian> esym(buf);
653 // We don't bother to set the st_name or the st_shndx field.
654 esym.put_st_value(from->value());
655 esym.put_st_size(from->symsize());
656 esym.put_st_info(from->binding(), from->type());
657 esym.put_st_other(from->visibility(), from->nonvis());
658 bool is_ordinary;
659 unsigned int shndx = from->shndx(&is_ordinary);
660 this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
661 from->version());
662 if (from->in_reg())
663 to->set_in_reg();
664 if (from->in_dyn())
665 to->set_in_dyn();
666 if (parameters->options().gc_sections())
667 this->gc_mark_dyn_syms(to);
668 }
669
670 // Record that a symbol is forced to be local by a version script or
671 // by visibility.
672
673 void
674 Symbol_table::force_local(Symbol* sym)
675 {
676 if (!sym->is_defined() && !sym->is_common())
677 return;
678 if (sym->is_forced_local())
679 {
680 // We already got this one.
681 return;
682 }
683 sym->set_is_forced_local();
684 this->forced_locals_.push_back(sym);
685 }
686
687 // Adjust NAME for wrapping, and update *NAME_KEY if necessary. This
688 // is only called for undefined symbols, when at least one --wrap
689 // option was used.
690
691 const char*
692 Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key)
693 {
694 // For some targets, we need to ignore a specific character when
695 // wrapping, and add it back later.
696 char prefix = '\0';
697 if (name[0] == parameters->target().wrap_char())
698 {
699 prefix = name[0];
700 ++name;
701 }
702
703 if (parameters->options().is_wrap(name))
704 {
705 // Turn NAME into __wrap_NAME.
706 std::string s;
707 if (prefix != '\0')
708 s += prefix;
709 s += "__wrap_";
710 s += name;
711
712 // This will give us both the old and new name in NAMEPOOL_, but
713 // that is OK. Only the versions we need will wind up in the
714 // real string table in the output file.
715 return this->namepool_.add(s.c_str(), true, name_key);
716 }
717
718 const char* const real_prefix = "__real_";
719 const size_t real_prefix_length = strlen(real_prefix);
720 if (strncmp(name, real_prefix, real_prefix_length) == 0
721 && parameters->options().is_wrap(name + real_prefix_length))
722 {
723 // Turn __real_NAME into NAME.
724 std::string s;
725 if (prefix != '\0')
726 s += prefix;
727 s += name + real_prefix_length;
728 return this->namepool_.add(s.c_str(), true, name_key);
729 }
730
731 return name;
732 }
733
734 // This is called when we see a symbol NAME/VERSION, and the symbol
735 // already exists in the symbol table, and VERSION is marked as being
736 // the default version. SYM is the NAME/VERSION symbol we just added.
737 // DEFAULT_IS_NEW is true if this is the first time we have seen the
738 // symbol NAME/NULL. PDEF points to the entry for NAME/NULL.
739
740 template<int size, bool big_endian>
741 void
742 Symbol_table::define_default_version(Sized_symbol<size>* sym,
743 bool default_is_new,
744 Symbol_table_type::iterator pdef)
745 {
746 if (default_is_new)
747 {
748 // This is the first time we have seen NAME/NULL. Make
749 // NAME/NULL point to NAME/VERSION, and mark SYM as the default
750 // version.
751 pdef->second = sym;
752 sym->set_is_default();
753 }
754 else if (pdef->second == sym)
755 {
756 // NAME/NULL already points to NAME/VERSION. Don't mark the
757 // symbol as the default if it is not already the default.
758 }
759 else
760 {
761 // This is the unfortunate case where we already have entries
762 // for both NAME/VERSION and NAME/NULL. We now see a symbol
763 // NAME/VERSION where VERSION is the default version. We have
764 // already resolved this new symbol with the existing
765 // NAME/VERSION symbol.
766
767 // It's possible that NAME/NULL and NAME/VERSION are both
768 // defined in regular objects. This can only happen if one
769 // object file defines foo and another defines foo@@ver. This
770 // is somewhat obscure, but we call it a multiple definition
771 // error.
772
773 // It's possible that NAME/NULL actually has a version, in which
774 // case it won't be the same as VERSION. This happens with
775 // ver_test_7.so in the testsuite for the symbol t2_2. We see
776 // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL. We
777 // then see an unadorned t2_2 in an object file and give it
778 // version VER1 from the version script. This looks like a
779 // default definition for VER1, so it looks like we should merge
780 // t2_2/NULL with t2_2/VER1. That doesn't make sense, but it's
781 // not obvious that this is an error, either. So we just punt.
782
783 // If one of the symbols has non-default visibility, and the
784 // other is defined in a shared object, then they are different
785 // symbols.
786
787 // Otherwise, we just resolve the symbols as though they were
788 // the same.
789
790 if (pdef->second->version() != NULL)
791 gold_assert(pdef->second->version() != sym->version());
792 else if (sym->visibility() != elfcpp::STV_DEFAULT
793 && pdef->second->is_from_dynobj())
794 ;
795 else if (pdef->second->visibility() != elfcpp::STV_DEFAULT
796 && sym->is_from_dynobj())
797 ;
798 else
799 {
800 const Sized_symbol<size>* symdef;
801 symdef = this->get_sized_symbol<size>(pdef->second);
802 Symbol_table::resolve<size, big_endian>(sym, symdef);
803 this->make_forwarder(pdef->second, sym);
804 pdef->second = sym;
805 sym->set_is_default();
806 }
807 }
808 }
809
810 // Add one symbol from OBJECT to the symbol table. NAME is symbol
811 // name and VERSION is the version; both are canonicalized. DEF is
812 // whether this is the default version. ST_SHNDX is the symbol's
813 // section index; IS_ORDINARY is whether this is a normal section
814 // rather than a special code.
815
816 // If DEF is true, then this is the definition of a default version of
817 // a symbol. That means that any lookup of NAME/NULL and any lookup
818 // of NAME/VERSION should always return the same symbol. This is
819 // obvious for references, but in particular we want to do this for
820 // definitions: overriding NAME/NULL should also override
821 // NAME/VERSION. If we don't do that, it would be very hard to
822 // override functions in a shared library which uses versioning.
823
824 // We implement this by simply making both entries in the hash table
825 // point to the same Symbol structure. That is easy enough if this is
826 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
827 // that we have seen both already, in which case they will both have
828 // independent entries in the symbol table. We can't simply change
829 // the symbol table entry, because we have pointers to the entries
830 // attached to the object files. So we mark the entry attached to the
831 // object file as a forwarder, and record it in the forwarders_ map.
832 // Note that entries in the hash table will never be marked as
833 // forwarders.
834 //
835 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
836 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
837 // for a special section code. ST_SHNDX may be modified if the symbol
838 // is defined in a section being discarded.
839
840 template<int size, bool big_endian>
841 Sized_symbol<size>*
842 Symbol_table::add_from_object(Object* object,
843 const char *name,
844 Stringpool::Key name_key,
845 const char *version,
846 Stringpool::Key version_key,
847 bool def,
848 const elfcpp::Sym<size, big_endian>& sym,
849 unsigned int st_shndx,
850 bool is_ordinary,
851 unsigned int orig_st_shndx)
852 {
853 // Print a message if this symbol is being traced.
854 if (parameters->options().is_trace_symbol(name))
855 {
856 if (orig_st_shndx == elfcpp::SHN_UNDEF)
857 gold_info(_("%s: reference to %s"), object->name().c_str(), name);
858 else
859 gold_info(_("%s: definition of %s"), object->name().c_str(), name);
860 }
861
862 // For an undefined symbol, we may need to adjust the name using
863 // --wrap.
864 if (orig_st_shndx == elfcpp::SHN_UNDEF
865 && parameters->options().any_wrap())
866 {
867 const char* wrap_name = this->wrap_symbol(name, &name_key);
868 if (wrap_name != name)
869 {
870 // If we see a reference to malloc with version GLIBC_2.0,
871 // and we turn it into a reference to __wrap_malloc, then we
872 // discard the version number. Otherwise the user would be
873 // required to specify the correct version for
874 // __wrap_malloc.
875 version = NULL;
876 version_key = 0;
877 name = wrap_name;
878 }
879 }
880
881 Symbol* const snull = NULL;
882 std::pair<typename Symbol_table_type::iterator, bool> ins =
883 this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
884 snull));
885
886 std::pair<typename Symbol_table_type::iterator, bool> insdef =
887 std::make_pair(this->table_.end(), false);
888 if (def)
889 {
890 const Stringpool::Key vnull_key = 0;
891 insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
892 vnull_key),
893 snull));
894 }
895
896 // ins.first: an iterator, which is a pointer to a pair.
897 // ins.first->first: the key (a pair of name and version).
898 // ins.first->second: the value (Symbol*).
899 // ins.second: true if new entry was inserted, false if not.
900
901 Sized_symbol<size>* ret;
902 bool was_undefined;
903 bool was_common;
904 if (!ins.second)
905 {
906 // We already have an entry for NAME/VERSION.
907 ret = this->get_sized_symbol<size>(ins.first->second);
908 gold_assert(ret != NULL);
909
910 was_undefined = ret->is_undefined();
911 was_common = ret->is_common();
912
913 this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
914 version);
915 if (parameters->options().gc_sections())
916 this->gc_mark_dyn_syms(ret);
917
918 if (def)
919 this->define_default_version<size, big_endian>(ret, insdef.second,
920 insdef.first);
921 }
922 else
923 {
924 // This is the first time we have seen NAME/VERSION.
925 gold_assert(ins.first->second == NULL);
926
927 if (def && !insdef.second)
928 {
929 // We already have an entry for NAME/NULL. If we override
930 // it, then change it to NAME/VERSION.
931 ret = this->get_sized_symbol<size>(insdef.first->second);
932
933 was_undefined = ret->is_undefined();
934 was_common = ret->is_common();
935
936 this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
937 version);
938 if (parameters->options().gc_sections())
939 this->gc_mark_dyn_syms(ret);
940 ins.first->second = ret;
941 }
942 else
943 {
944 was_undefined = false;
945 was_common = false;
946
947 Sized_target<size, big_endian>* target =
948 parameters->sized_target<size, big_endian>();
949 if (!target->has_make_symbol())
950 ret = new Sized_symbol<size>();
951 else
952 {
953 ret = target->make_symbol();
954 if (ret == NULL)
955 {
956 // This means that we don't want a symbol table
957 // entry after all.
958 if (!def)
959 this->table_.erase(ins.first);
960 else
961 {
962 this->table_.erase(insdef.first);
963 // Inserting insdef invalidated ins.
964 this->table_.erase(std::make_pair(name_key,
965 version_key));
966 }
967 return NULL;
968 }
969 }
970
971 ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
972
973 ins.first->second = ret;
974 if (def)
975 {
976 // This is the first time we have seen NAME/NULL. Point
977 // it at the new entry for NAME/VERSION.
978 gold_assert(insdef.second);
979 insdef.first->second = ret;
980 }
981 }
982
983 if (def)
984 ret->set_is_default();
985 }
986
987 // Record every time we see a new undefined symbol, to speed up
988 // archive groups.
989 if (!was_undefined && ret->is_undefined())
990 ++this->saw_undefined_;
991
992 // Keep track of common symbols, to speed up common symbol
993 // allocation.
994 if (!was_common && ret->is_common())
995 {
996 if (ret->type() == elfcpp::STT_TLS)
997 this->tls_commons_.push_back(ret);
998 else if (!is_ordinary
999 && st_shndx == parameters->target().small_common_shndx())
1000 this->small_commons_.push_back(ret);
1001 else if (!is_ordinary
1002 && st_shndx == parameters->target().large_common_shndx())
1003 this->large_commons_.push_back(ret);
1004 else
1005 this->commons_.push_back(ret);
1006 }
1007
1008 // If we're not doing a relocatable link, then any symbol with
1009 // hidden or internal visibility is local.
1010 if ((ret->visibility() == elfcpp::STV_HIDDEN
1011 || ret->visibility() == elfcpp::STV_INTERNAL)
1012 && (ret->binding() == elfcpp::STB_GLOBAL
1013 || ret->binding() == elfcpp::STB_GNU_UNIQUE
1014 || ret->binding() == elfcpp::STB_WEAK)
1015 && !parameters->options().relocatable())
1016 this->force_local(ret);
1017
1018 return ret;
1019 }
1020
1021 // Add all the symbols in a relocatable object to the hash table.
1022
1023 template<int size, bool big_endian>
1024 void
1025 Symbol_table::add_from_relobj(
1026 Sized_relobj<size, big_endian>* relobj,
1027 const unsigned char* syms,
1028 size_t count,
1029 size_t symndx_offset,
1030 const char* sym_names,
1031 size_t sym_name_size,
1032 typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1033 size_t *defined)
1034 {
1035 *defined = 0;
1036
1037 gold_assert(size == parameters->target().get_size());
1038
1039 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1040
1041 const bool just_symbols = relobj->just_symbols();
1042
1043 const unsigned char* p = syms;
1044 for (size_t i = 0; i < count; ++i, p += sym_size)
1045 {
1046 (*sympointers)[i] = NULL;
1047
1048 elfcpp::Sym<size, big_endian> sym(p);
1049
1050 unsigned int st_name = sym.get_st_name();
1051 if (st_name >= sym_name_size)
1052 {
1053 relobj->error(_("bad global symbol name offset %u at %zu"),
1054 st_name, i);
1055 continue;
1056 }
1057
1058 const char* name = sym_names + st_name;
1059
1060 bool is_ordinary;
1061 unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
1062 sym.get_st_shndx(),
1063 &is_ordinary);
1064 unsigned int orig_st_shndx = st_shndx;
1065 if (!is_ordinary)
1066 orig_st_shndx = elfcpp::SHN_UNDEF;
1067
1068 if (st_shndx != elfcpp::SHN_UNDEF)
1069 ++*defined;
1070
1071 // A symbol defined in a section which we are not including must
1072 // be treated as an undefined symbol.
1073 if (st_shndx != elfcpp::SHN_UNDEF
1074 && is_ordinary
1075 && !relobj->is_section_included(st_shndx))
1076 st_shndx = elfcpp::SHN_UNDEF;
1077
1078 // In an object file, an '@' in the name separates the symbol
1079 // name from the version name. If there are two '@' characters,
1080 // this is the default version.
1081 const char* ver = strchr(name, '@');
1082 Stringpool::Key ver_key = 0;
1083 int namelen = 0;
1084 // DEF: is the version default? LOCAL: is the symbol forced local?
1085 bool def = false;
1086 bool local = false;
1087
1088 if (ver != NULL)
1089 {
1090 // The symbol name is of the form foo@VERSION or foo@@VERSION
1091 namelen = ver - name;
1092 ++ver;
1093 if (*ver == '@')
1094 {
1095 def = true;
1096 ++ver;
1097 }
1098 ver = this->namepool_.add(ver, true, &ver_key);
1099 }
1100 // We don't want to assign a version to an undefined symbol,
1101 // even if it is listed in the version script. FIXME: What
1102 // about a common symbol?
1103 else
1104 {
1105 namelen = strlen(name);
1106 if (!this->version_script_.empty()
1107 && st_shndx != elfcpp::SHN_UNDEF)
1108 {
1109 // The symbol name did not have a version, but the
1110 // version script may assign a version anyway.
1111 std::string version;
1112 if (this->version_script_.get_symbol_version(name, &version))
1113 {
1114 // The version can be empty if the version script is
1115 // only used to force some symbols to be local.
1116 if (!version.empty())
1117 {
1118 ver = this->namepool_.add_with_length(version.c_str(),
1119 version.length(),
1120 true,
1121 &ver_key);
1122 def = true;
1123 }
1124 }
1125 else if (this->version_script_.symbol_is_local(name))
1126 local = true;
1127 }
1128 }
1129
1130 elfcpp::Sym<size, big_endian>* psym = &sym;
1131 unsigned char symbuf[sym_size];
1132 elfcpp::Sym<size, big_endian> sym2(symbuf);
1133 if (just_symbols)
1134 {
1135 memcpy(symbuf, p, sym_size);
1136 elfcpp::Sym_write<size, big_endian> sw(symbuf);
1137 if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
1138 {
1139 // Symbol values in object files are section relative.
1140 // This is normally what we want, but since here we are
1141 // converting the symbol to absolute we need to add the
1142 // section address. The section address in an object
1143 // file is normally zero, but people can use a linker
1144 // script to change it.
1145 sw.put_st_value(sym.get_st_value()
1146 + relobj->section_address(orig_st_shndx));
1147 }
1148 st_shndx = elfcpp::SHN_ABS;
1149 is_ordinary = false;
1150 psym = &sym2;
1151 }
1152
1153 // Fix up visibility if object has no-export set.
1154 if (relobj->no_export()
1155 && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary))
1156 {
1157 // We may have copied symbol already above.
1158 if (psym != &sym2)
1159 {
1160 memcpy(symbuf, p, sym_size);
1161 psym = &sym2;
1162 }
1163
1164 elfcpp::STV visibility = sym2.get_st_visibility();
1165 if (visibility == elfcpp::STV_DEFAULT
1166 || visibility == elfcpp::STV_PROTECTED)
1167 {
1168 elfcpp::Sym_write<size, big_endian> sw(symbuf);
1169 unsigned char nonvis = sym2.get_st_nonvis();
1170 sw.put_st_other(elfcpp::STV_HIDDEN, nonvis);
1171 }
1172 }
1173
1174 Stringpool::Key name_key;
1175 name = this->namepool_.add_with_length(name, namelen, true,
1176 &name_key);
1177
1178 Sized_symbol<size>* res;
1179 res = this->add_from_object(relobj, name, name_key, ver, ver_key,
1180 def, *psym, st_shndx, is_ordinary,
1181 orig_st_shndx);
1182
1183 // If building a shared library using garbage collection, do not
1184 // treat externally visible symbols as garbage.
1185 if (parameters->options().gc_sections()
1186 && parameters->options().shared())
1187 this->gc_mark_symbol_for_shlib(res);
1188
1189 if (local)
1190 this->force_local(res);
1191
1192 (*sympointers)[i] = res;
1193 }
1194 }
1195
1196 // Add a symbol from a plugin-claimed file.
1197
1198 template<int size, bool big_endian>
1199 Symbol*
1200 Symbol_table::add_from_pluginobj(
1201 Sized_pluginobj<size, big_endian>* obj,
1202 const char* name,
1203 const char* ver,
1204 elfcpp::Sym<size, big_endian>* sym)
1205 {
1206 unsigned int st_shndx = sym->get_st_shndx();
1207 bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE;
1208
1209 Stringpool::Key ver_key = 0;
1210 bool def = false;
1211 bool local = false;
1212
1213 if (ver != NULL)
1214 {
1215 ver = this->namepool_.add(ver, true, &ver_key);
1216 }
1217 // We don't want to assign a version to an undefined symbol,
1218 // even if it is listed in the version script. FIXME: What
1219 // about a common symbol?
1220 else
1221 {
1222 if (!this->version_script_.empty()
1223 && st_shndx != elfcpp::SHN_UNDEF)
1224 {
1225 // The symbol name did not have a version, but the
1226 // version script may assign a version anyway.
1227 std::string version;
1228 if (this->version_script_.get_symbol_version(name, &version))
1229 {
1230 // The version can be empty if the version script is
1231 // only used to force some symbols to be local.
1232 if (!version.empty())
1233 {
1234 ver = this->namepool_.add_with_length(version.c_str(),
1235 version.length(),
1236 true,
1237 &ver_key);
1238 def = true;
1239 }
1240 }
1241 else if (this->version_script_.symbol_is_local(name))
1242 local = true;
1243 }
1244 }
1245
1246 Stringpool::Key name_key;
1247 name = this->namepool_.add(name, true, &name_key);
1248
1249 Sized_symbol<size>* res;
1250 res = this->add_from_object(obj, name, name_key, ver, ver_key,
1251 def, *sym, st_shndx, is_ordinary, st_shndx);
1252
1253 if (local)
1254 this->force_local(res);
1255
1256 return res;
1257 }
1258
1259 // Add all the symbols in a dynamic object to the hash table.
1260
1261 template<int size, bool big_endian>
1262 void
1263 Symbol_table::add_from_dynobj(
1264 Sized_dynobj<size, big_endian>* dynobj,
1265 const unsigned char* syms,
1266 size_t count,
1267 const char* sym_names,
1268 size_t sym_name_size,
1269 const unsigned char* versym,
1270 size_t versym_size,
1271 const std::vector<const char*>* version_map,
1272 typename Sized_relobj<size, big_endian>::Symbols* sympointers,
1273 size_t* defined)
1274 {
1275 *defined = 0;
1276
1277 gold_assert(size == parameters->target().get_size());
1278
1279 if (dynobj->just_symbols())
1280 {
1281 gold_error(_("--just-symbols does not make sense with a shared object"));
1282 return;
1283 }
1284
1285 if (versym != NULL && versym_size / 2 < count)
1286 {
1287 dynobj->error(_("too few symbol versions"));
1288 return;
1289 }
1290
1291 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1292
1293 // We keep a list of all STT_OBJECT symbols, so that we can resolve
1294 // weak aliases. This is necessary because if the dynamic object
1295 // provides the same variable under two names, one of which is a
1296 // weak definition, and the regular object refers to the weak
1297 // definition, we have to put both the weak definition and the
1298 // strong definition into the dynamic symbol table. Given a weak
1299 // definition, the only way that we can find the corresponding
1300 // strong definition, if any, is to search the symbol table.
1301 std::vector<Sized_symbol<size>*> object_symbols;
1302
1303 const unsigned char* p = syms;
1304 const unsigned char* vs = versym;
1305 for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1306 {
1307 elfcpp::Sym<size, big_endian> sym(p);
1308
1309 if (sympointers != NULL)
1310 (*sympointers)[i] = NULL;
1311
1312 // Ignore symbols with local binding or that have
1313 // internal or hidden visibility.
1314 if (sym.get_st_bind() == elfcpp::STB_LOCAL
1315 || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1316 || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1317 continue;
1318
1319 // A protected symbol in a shared library must be treated as a
1320 // normal symbol when viewed from outside the shared library.
1321 // Implement this by overriding the visibility here.
1322 elfcpp::Sym<size, big_endian>* psym = &sym;
1323 unsigned char symbuf[sym_size];
1324 elfcpp::Sym<size, big_endian> sym2(symbuf);
1325 if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1326 {
1327 memcpy(symbuf, p, sym_size);
1328 elfcpp::Sym_write<size, big_endian> sw(symbuf);
1329 sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1330 psym = &sym2;
1331 }
1332
1333 unsigned int st_name = psym->get_st_name();
1334 if (st_name >= sym_name_size)
1335 {
1336 dynobj->error(_("bad symbol name offset %u at %zu"),
1337 st_name, i);
1338 continue;
1339 }
1340
1341 const char* name = sym_names + st_name;
1342
1343 bool is_ordinary;
1344 unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1345 &is_ordinary);
1346
1347 if (st_shndx != elfcpp::SHN_UNDEF)
1348 ++*defined;
1349
1350 Sized_symbol<size>* res;
1351
1352 if (versym == NULL)
1353 {
1354 Stringpool::Key name_key;
1355 name = this->namepool_.add(name, true, &name_key);
1356 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1357 false, *psym, st_shndx, is_ordinary,
1358 st_shndx);
1359 }
1360 else
1361 {
1362 // Read the version information.
1363
1364 unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1365
1366 bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1367 v &= elfcpp::VERSYM_VERSION;
1368
1369 // The Sun documentation says that V can be VER_NDX_LOCAL,
1370 // or VER_NDX_GLOBAL, or a version index. The meaning of
1371 // VER_NDX_LOCAL is defined as "Symbol has local scope."
1372 // The old GNU linker will happily generate VER_NDX_LOCAL
1373 // for an undefined symbol. I don't know what the Sun
1374 // linker will generate.
1375
1376 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1377 && st_shndx != elfcpp::SHN_UNDEF)
1378 {
1379 // This symbol should not be visible outside the object.
1380 continue;
1381 }
1382
1383 // At this point we are definitely going to add this symbol.
1384 Stringpool::Key name_key;
1385 name = this->namepool_.add(name, true, &name_key);
1386
1387 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1388 || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1389 {
1390 // This symbol does not have a version.
1391 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1392 false, *psym, st_shndx, is_ordinary,
1393 st_shndx);
1394 }
1395 else
1396 {
1397 if (v >= version_map->size())
1398 {
1399 dynobj->error(_("versym for symbol %zu out of range: %u"),
1400 i, v);
1401 continue;
1402 }
1403
1404 const char* version = (*version_map)[v];
1405 if (version == NULL)
1406 {
1407 dynobj->error(_("versym for symbol %zu has no name: %u"),
1408 i, v);
1409 continue;
1410 }
1411
1412 Stringpool::Key version_key;
1413 version = this->namepool_.add(version, true, &version_key);
1414
1415 // If this is an absolute symbol, and the version name
1416 // and symbol name are the same, then this is the
1417 // version definition symbol. These symbols exist to
1418 // support using -u to pull in particular versions. We
1419 // do not want to record a version for them.
1420 if (st_shndx == elfcpp::SHN_ABS
1421 && !is_ordinary
1422 && name_key == version_key)
1423 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1424 false, *psym, st_shndx, is_ordinary,
1425 st_shndx);
1426 else
1427 {
1428 const bool def = (!hidden
1429 && st_shndx != elfcpp::SHN_UNDEF);
1430 res = this->add_from_object(dynobj, name, name_key, version,
1431 version_key, def, *psym, st_shndx,
1432 is_ordinary, st_shndx);
1433 }
1434 }
1435 }
1436
1437 // Note that it is possible that RES was overridden by an
1438 // earlier object, in which case it can't be aliased here.
1439 if (st_shndx != elfcpp::SHN_UNDEF
1440 && is_ordinary
1441 && psym->get_st_type() == elfcpp::STT_OBJECT
1442 && res->source() == Symbol::FROM_OBJECT
1443 && res->object() == dynobj)
1444 object_symbols.push_back(res);
1445
1446 if (sympointers != NULL)
1447 (*sympointers)[i] = res;
1448 }
1449
1450 this->record_weak_aliases(&object_symbols);
1451 }
1452
1453 // This is used to sort weak aliases. We sort them first by section
1454 // index, then by offset, then by weak ahead of strong.
1455
1456 template<int size>
1457 class Weak_alias_sorter
1458 {
1459 public:
1460 bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1461 };
1462
1463 template<int size>
1464 bool
1465 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1466 const Sized_symbol<size>* s2) const
1467 {
1468 bool is_ordinary;
1469 unsigned int s1_shndx = s1->shndx(&is_ordinary);
1470 gold_assert(is_ordinary);
1471 unsigned int s2_shndx = s2->shndx(&is_ordinary);
1472 gold_assert(is_ordinary);
1473 if (s1_shndx != s2_shndx)
1474 return s1_shndx < s2_shndx;
1475
1476 if (s1->value() != s2->value())
1477 return s1->value() < s2->value();
1478 if (s1->binding() != s2->binding())
1479 {
1480 if (s1->binding() == elfcpp::STB_WEAK)
1481 return true;
1482 if (s2->binding() == elfcpp::STB_WEAK)
1483 return false;
1484 }
1485 return std::string(s1->name()) < std::string(s2->name());
1486 }
1487
1488 // SYMBOLS is a list of object symbols from a dynamic object. Look
1489 // for any weak aliases, and record them so that if we add the weak
1490 // alias to the dynamic symbol table, we also add the corresponding
1491 // strong symbol.
1492
1493 template<int size>
1494 void
1495 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1496 {
1497 // Sort the vector by section index, then by offset, then by weak
1498 // ahead of strong.
1499 std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1500
1501 // Walk through the vector. For each weak definition, record
1502 // aliases.
1503 for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1504 symbols->begin();
1505 p != symbols->end();
1506 ++p)
1507 {
1508 if ((*p)->binding() != elfcpp::STB_WEAK)
1509 continue;
1510
1511 // Build a circular list of weak aliases. Each symbol points to
1512 // the next one in the circular list.
1513
1514 Sized_symbol<size>* from_sym = *p;
1515 typename std::vector<Sized_symbol<size>*>::const_iterator q;
1516 for (q = p + 1; q != symbols->end(); ++q)
1517 {
1518 bool dummy;
1519 if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1520 || (*q)->value() != from_sym->value())
1521 break;
1522
1523 this->weak_aliases_[from_sym] = *q;
1524 from_sym->set_has_alias();
1525 from_sym = *q;
1526 }
1527
1528 if (from_sym != *p)
1529 {
1530 this->weak_aliases_[from_sym] = *p;
1531 from_sym->set_has_alias();
1532 }
1533
1534 p = q - 1;
1535 }
1536 }
1537
1538 // Create and return a specially defined symbol. If ONLY_IF_REF is
1539 // true, then only create the symbol if there is a reference to it.
1540 // If this does not return NULL, it sets *POLDSYM to the existing
1541 // symbol if there is one. This sets *RESOLVE_OLDSYM if we should
1542 // resolve the newly created symbol to the old one. This
1543 // canonicalizes *PNAME and *PVERSION.
1544
1545 template<int size, bool big_endian>
1546 Sized_symbol<size>*
1547 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1548 bool only_if_ref,
1549 Sized_symbol<size>** poldsym,
1550 bool *resolve_oldsym)
1551 {
1552 *resolve_oldsym = false;
1553
1554 // If the caller didn't give us a version, see if we get one from
1555 // the version script.
1556 std::string v;
1557 bool is_default_version = false;
1558 if (*pversion == NULL)
1559 {
1560 if (this->version_script_.get_symbol_version(*pname, &v))
1561 {
1562 if (!v.empty())
1563 *pversion = v.c_str();
1564
1565 // If we get the version from a version script, then we are
1566 // also the default version.
1567 is_default_version = true;
1568 }
1569 }
1570
1571 Symbol* oldsym;
1572 Sized_symbol<size>* sym;
1573
1574 bool add_to_table = false;
1575 typename Symbol_table_type::iterator add_loc = this->table_.end();
1576 bool add_def_to_table = false;
1577 typename Symbol_table_type::iterator add_def_loc = this->table_.end();
1578
1579 if (only_if_ref)
1580 {
1581 oldsym = this->lookup(*pname, *pversion);
1582 if (oldsym == NULL && is_default_version)
1583 oldsym = this->lookup(*pname, NULL);
1584 if (oldsym == NULL || !oldsym->is_undefined())
1585 return NULL;
1586
1587 *pname = oldsym->name();
1588 if (!is_default_version)
1589 *pversion = oldsym->version();
1590 }
1591 else
1592 {
1593 // Canonicalize NAME and VERSION.
1594 Stringpool::Key name_key;
1595 *pname = this->namepool_.add(*pname, true, &name_key);
1596
1597 Stringpool::Key version_key = 0;
1598 if (*pversion != NULL)
1599 *pversion = this->namepool_.add(*pversion, true, &version_key);
1600
1601 Symbol* const snull = NULL;
1602 std::pair<typename Symbol_table_type::iterator, bool> ins =
1603 this->table_.insert(std::make_pair(std::make_pair(name_key,
1604 version_key),
1605 snull));
1606
1607 std::pair<typename Symbol_table_type::iterator, bool> insdef =
1608 std::make_pair(this->table_.end(), false);
1609 if (is_default_version)
1610 {
1611 const Stringpool::Key vnull = 0;
1612 insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
1613 vnull),
1614 snull));
1615 }
1616
1617 if (!ins.second)
1618 {
1619 // We already have a symbol table entry for NAME/VERSION.
1620 oldsym = ins.first->second;
1621 gold_assert(oldsym != NULL);
1622
1623 if (is_default_version)
1624 {
1625 Sized_symbol<size>* soldsym =
1626 this->get_sized_symbol<size>(oldsym);
1627 this->define_default_version<size, big_endian>(soldsym,
1628 insdef.second,
1629 insdef.first);
1630 }
1631 }
1632 else
1633 {
1634 // We haven't seen this symbol before.
1635 gold_assert(ins.first->second == NULL);
1636
1637 add_to_table = true;
1638 add_loc = ins.first;
1639
1640 if (is_default_version && !insdef.second)
1641 {
1642 // We are adding NAME/VERSION, and it is the default
1643 // version. We already have an entry for NAME/NULL.
1644 oldsym = insdef.first->second;
1645 *resolve_oldsym = true;
1646 }
1647 else
1648 {
1649 oldsym = NULL;
1650
1651 if (is_default_version)
1652 {
1653 add_def_to_table = true;
1654 add_def_loc = insdef.first;
1655 }
1656 }
1657 }
1658 }
1659
1660 const Target& target = parameters->target();
1661 if (!target.has_make_symbol())
1662 sym = new Sized_symbol<size>();
1663 else
1664 {
1665 Sized_target<size, big_endian>* sized_target =
1666 parameters->sized_target<size, big_endian>();
1667 sym = sized_target->make_symbol();
1668 if (sym == NULL)
1669 return NULL;
1670 }
1671
1672 if (add_to_table)
1673 add_loc->second = sym;
1674 else
1675 gold_assert(oldsym != NULL);
1676
1677 if (add_def_to_table)
1678 add_def_loc->second = sym;
1679
1680 *poldsym = this->get_sized_symbol<size>(oldsym);
1681
1682 return sym;
1683 }
1684
1685 // Define a symbol based on an Output_data.
1686
1687 Symbol*
1688 Symbol_table::define_in_output_data(const char* name,
1689 const char* version,
1690 Defined defined,
1691 Output_data* od,
1692 uint64_t value,
1693 uint64_t symsize,
1694 elfcpp::STT type,
1695 elfcpp::STB binding,
1696 elfcpp::STV visibility,
1697 unsigned char nonvis,
1698 bool offset_is_from_end,
1699 bool only_if_ref)
1700 {
1701 if (parameters->target().get_size() == 32)
1702 {
1703 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1704 return this->do_define_in_output_data<32>(name, version, defined, od,
1705 value, symsize, type, binding,
1706 visibility, nonvis,
1707 offset_is_from_end,
1708 only_if_ref);
1709 #else
1710 gold_unreachable();
1711 #endif
1712 }
1713 else if (parameters->target().get_size() == 64)
1714 {
1715 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1716 return this->do_define_in_output_data<64>(name, version, defined, od,
1717 value, symsize, type, binding,
1718 visibility, nonvis,
1719 offset_is_from_end,
1720 only_if_ref);
1721 #else
1722 gold_unreachable();
1723 #endif
1724 }
1725 else
1726 gold_unreachable();
1727 }
1728
1729 // Define a symbol in an Output_data, sized version.
1730
1731 template<int size>
1732 Sized_symbol<size>*
1733 Symbol_table::do_define_in_output_data(
1734 const char* name,
1735 const char* version,
1736 Defined defined,
1737 Output_data* od,
1738 typename elfcpp::Elf_types<size>::Elf_Addr value,
1739 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1740 elfcpp::STT type,
1741 elfcpp::STB binding,
1742 elfcpp::STV visibility,
1743 unsigned char nonvis,
1744 bool offset_is_from_end,
1745 bool only_if_ref)
1746 {
1747 Sized_symbol<size>* sym;
1748 Sized_symbol<size>* oldsym;
1749 bool resolve_oldsym;
1750
1751 if (parameters->target().is_big_endian())
1752 {
1753 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1754 sym = this->define_special_symbol<size, true>(&name, &version,
1755 only_if_ref, &oldsym,
1756 &resolve_oldsym);
1757 #else
1758 gold_unreachable();
1759 #endif
1760 }
1761 else
1762 {
1763 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1764 sym = this->define_special_symbol<size, false>(&name, &version,
1765 only_if_ref, &oldsym,
1766 &resolve_oldsym);
1767 #else
1768 gold_unreachable();
1769 #endif
1770 }
1771
1772 if (sym == NULL)
1773 return NULL;
1774
1775 sym->init_output_data(name, version, od, value, symsize, type, binding,
1776 visibility, nonvis, offset_is_from_end);
1777
1778 if (oldsym == NULL)
1779 {
1780 if (binding == elfcpp::STB_LOCAL
1781 || this->version_script_.symbol_is_local(name))
1782 this->force_local(sym);
1783 else if (version != NULL)
1784 sym->set_is_default();
1785 return sym;
1786 }
1787
1788 if (Symbol_table::should_override_with_special(oldsym, defined))
1789 this->override_with_special(oldsym, sym);
1790
1791 if (resolve_oldsym)
1792 return sym;
1793 else
1794 {
1795 delete sym;
1796 return oldsym;
1797 }
1798 }
1799
1800 // Define a symbol based on an Output_segment.
1801
1802 Symbol*
1803 Symbol_table::define_in_output_segment(const char* name,
1804 const char* version,
1805 Defined defined,
1806 Output_segment* os,
1807 uint64_t value,
1808 uint64_t symsize,
1809 elfcpp::STT type,
1810 elfcpp::STB binding,
1811 elfcpp::STV visibility,
1812 unsigned char nonvis,
1813 Symbol::Segment_offset_base offset_base,
1814 bool only_if_ref)
1815 {
1816 if (parameters->target().get_size() == 32)
1817 {
1818 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1819 return this->do_define_in_output_segment<32>(name, version, defined, os,
1820 value, symsize, type,
1821 binding, visibility, nonvis,
1822 offset_base, only_if_ref);
1823 #else
1824 gold_unreachable();
1825 #endif
1826 }
1827 else if (parameters->target().get_size() == 64)
1828 {
1829 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1830 return this->do_define_in_output_segment<64>(name, version, defined, os,
1831 value, symsize, type,
1832 binding, visibility, nonvis,
1833 offset_base, only_if_ref);
1834 #else
1835 gold_unreachable();
1836 #endif
1837 }
1838 else
1839 gold_unreachable();
1840 }
1841
1842 // Define a symbol in an Output_segment, sized version.
1843
1844 template<int size>
1845 Sized_symbol<size>*
1846 Symbol_table::do_define_in_output_segment(
1847 const char* name,
1848 const char* version,
1849 Defined defined,
1850 Output_segment* os,
1851 typename elfcpp::Elf_types<size>::Elf_Addr value,
1852 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1853 elfcpp::STT type,
1854 elfcpp::STB binding,
1855 elfcpp::STV visibility,
1856 unsigned char nonvis,
1857 Symbol::Segment_offset_base offset_base,
1858 bool only_if_ref)
1859 {
1860 Sized_symbol<size>* sym;
1861 Sized_symbol<size>* oldsym;
1862 bool resolve_oldsym;
1863
1864 if (parameters->target().is_big_endian())
1865 {
1866 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1867 sym = this->define_special_symbol<size, true>(&name, &version,
1868 only_if_ref, &oldsym,
1869 &resolve_oldsym);
1870 #else
1871 gold_unreachable();
1872 #endif
1873 }
1874 else
1875 {
1876 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1877 sym = this->define_special_symbol<size, false>(&name, &version,
1878 only_if_ref, &oldsym,
1879 &resolve_oldsym);
1880 #else
1881 gold_unreachable();
1882 #endif
1883 }
1884
1885 if (sym == NULL)
1886 return NULL;
1887
1888 sym->init_output_segment(name, version, os, value, symsize, type, binding,
1889 visibility, nonvis, offset_base);
1890
1891 if (oldsym == NULL)
1892 {
1893 if (binding == elfcpp::STB_LOCAL
1894 || this->version_script_.symbol_is_local(name))
1895 this->force_local(sym);
1896 else if (version != NULL)
1897 sym->set_is_default();
1898 return sym;
1899 }
1900
1901 if (Symbol_table::should_override_with_special(oldsym, defined))
1902 this->override_with_special(oldsym, sym);
1903
1904 if (resolve_oldsym)
1905 return sym;
1906 else
1907 {
1908 delete sym;
1909 return oldsym;
1910 }
1911 }
1912
1913 // Define a special symbol with a constant value. It is a multiple
1914 // definition error if this symbol is already defined.
1915
1916 Symbol*
1917 Symbol_table::define_as_constant(const char* name,
1918 const char* version,
1919 Defined defined,
1920 uint64_t value,
1921 uint64_t symsize,
1922 elfcpp::STT type,
1923 elfcpp::STB binding,
1924 elfcpp::STV visibility,
1925 unsigned char nonvis,
1926 bool only_if_ref,
1927 bool force_override)
1928 {
1929 if (parameters->target().get_size() == 32)
1930 {
1931 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1932 return this->do_define_as_constant<32>(name, version, defined, value,
1933 symsize, type, binding,
1934 visibility, nonvis, only_if_ref,
1935 force_override);
1936 #else
1937 gold_unreachable();
1938 #endif
1939 }
1940 else if (parameters->target().get_size() == 64)
1941 {
1942 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1943 return this->do_define_as_constant<64>(name, version, defined, value,
1944 symsize, type, binding,
1945 visibility, nonvis, only_if_ref,
1946 force_override);
1947 #else
1948 gold_unreachable();
1949 #endif
1950 }
1951 else
1952 gold_unreachable();
1953 }
1954
1955 // Define a symbol as a constant, sized version.
1956
1957 template<int size>
1958 Sized_symbol<size>*
1959 Symbol_table::do_define_as_constant(
1960 const char* name,
1961 const char* version,
1962 Defined defined,
1963 typename elfcpp::Elf_types<size>::Elf_Addr value,
1964 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1965 elfcpp::STT type,
1966 elfcpp::STB binding,
1967 elfcpp::STV visibility,
1968 unsigned char nonvis,
1969 bool only_if_ref,
1970 bool force_override)
1971 {
1972 Sized_symbol<size>* sym;
1973 Sized_symbol<size>* oldsym;
1974 bool resolve_oldsym;
1975
1976 if (parameters->target().is_big_endian())
1977 {
1978 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1979 sym = this->define_special_symbol<size, true>(&name, &version,
1980 only_if_ref, &oldsym,
1981 &resolve_oldsym);
1982 #else
1983 gold_unreachable();
1984 #endif
1985 }
1986 else
1987 {
1988 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1989 sym = this->define_special_symbol<size, false>(&name, &version,
1990 only_if_ref, &oldsym,
1991 &resolve_oldsym);
1992 #else
1993 gold_unreachable();
1994 #endif
1995 }
1996
1997 if (sym == NULL)
1998 return NULL;
1999
2000 sym->init_constant(name, version, value, symsize, type, binding, visibility,
2001 nonvis);
2002
2003 if (oldsym == NULL)
2004 {
2005 // Version symbols are absolute symbols with name == version.
2006 // We don't want to force them to be local.
2007 if ((version == NULL
2008 || name != version
2009 || value != 0)
2010 && (binding == elfcpp::STB_LOCAL
2011 || this->version_script_.symbol_is_local(name)))
2012 this->force_local(sym);
2013 else if (version != NULL
2014 && (name != version || value != 0))
2015 sym->set_is_default();
2016 return sym;
2017 }
2018
2019 if (force_override
2020 || Symbol_table::should_override_with_special(oldsym, defined))
2021 this->override_with_special(oldsym, sym);
2022
2023 if (resolve_oldsym)
2024 return sym;
2025 else
2026 {
2027 delete sym;
2028 return oldsym;
2029 }
2030 }
2031
2032 // Define a set of symbols in output sections.
2033
2034 void
2035 Symbol_table::define_symbols(const Layout* layout, int count,
2036 const Define_symbol_in_section* p,
2037 bool only_if_ref)
2038 {
2039 for (int i = 0; i < count; ++i, ++p)
2040 {
2041 Output_section* os = layout->find_output_section(p->output_section);
2042 if (os != NULL)
2043 this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value,
2044 p->size, p->type, p->binding,
2045 p->visibility, p->nonvis,
2046 p->offset_is_from_end,
2047 only_if_ref || p->only_if_ref);
2048 else
2049 this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2050 p->type, p->binding, p->visibility, p->nonvis,
2051 only_if_ref || p->only_if_ref,
2052 false);
2053 }
2054 }
2055
2056 // Define a set of symbols in output segments.
2057
2058 void
2059 Symbol_table::define_symbols(const Layout* layout, int count,
2060 const Define_symbol_in_segment* p,
2061 bool only_if_ref)
2062 {
2063 for (int i = 0; i < count; ++i, ++p)
2064 {
2065 Output_segment* os = layout->find_output_segment(p->segment_type,
2066 p->segment_flags_set,
2067 p->segment_flags_clear);
2068 if (os != NULL)
2069 this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value,
2070 p->size, p->type, p->binding,
2071 p->visibility, p->nonvis,
2072 p->offset_base,
2073 only_if_ref || p->only_if_ref);
2074 else
2075 this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size,
2076 p->type, p->binding, p->visibility, p->nonvis,
2077 only_if_ref || p->only_if_ref,
2078 false);
2079 }
2080 }
2081
2082 // Define CSYM using a COPY reloc. POSD is the Output_data where the
2083 // symbol should be defined--typically a .dyn.bss section. VALUE is
2084 // the offset within POSD.
2085
2086 template<int size>
2087 void
2088 Symbol_table::define_with_copy_reloc(
2089 Sized_symbol<size>* csym,
2090 Output_data* posd,
2091 typename elfcpp::Elf_types<size>::Elf_Addr value)
2092 {
2093 gold_assert(csym->is_from_dynobj());
2094 gold_assert(!csym->is_copied_from_dynobj());
2095 Object* object = csym->object();
2096 gold_assert(object->is_dynamic());
2097 Dynobj* dynobj = static_cast<Dynobj*>(object);
2098
2099 // Our copied variable has to override any variable in a shared
2100 // library.
2101 elfcpp::STB binding = csym->binding();
2102 if (binding == elfcpp::STB_WEAK)
2103 binding = elfcpp::STB_GLOBAL;
2104
2105 this->define_in_output_data(csym->name(), csym->version(), COPY,
2106 posd, value, csym->symsize(),
2107 csym->type(), binding,
2108 csym->visibility(), csym->nonvis(),
2109 false, false);
2110
2111 csym->set_is_copied_from_dynobj();
2112 csym->set_needs_dynsym_entry();
2113
2114 this->copied_symbol_dynobjs_[csym] = dynobj;
2115
2116 // We have now defined all aliases, but we have not entered them all
2117 // in the copied_symbol_dynobjs_ map.
2118 if (csym->has_alias())
2119 {
2120 Symbol* sym = csym;
2121 while (true)
2122 {
2123 sym = this->weak_aliases_[sym];
2124 if (sym == csym)
2125 break;
2126 gold_assert(sym->output_data() == posd);
2127
2128 sym->set_is_copied_from_dynobj();
2129 this->copied_symbol_dynobjs_[sym] = dynobj;
2130 }
2131 }
2132 }
2133
2134 // SYM is defined using a COPY reloc. Return the dynamic object where
2135 // the original definition was found.
2136
2137 Dynobj*
2138 Symbol_table::get_copy_source(const Symbol* sym) const
2139 {
2140 gold_assert(sym->is_copied_from_dynobj());
2141 Copied_symbol_dynobjs::const_iterator p =
2142 this->copied_symbol_dynobjs_.find(sym);
2143 gold_assert(p != this->copied_symbol_dynobjs_.end());
2144 return p->second;
2145 }
2146
2147 // Add any undefined symbols named on the command line.
2148
2149 void
2150 Symbol_table::add_undefined_symbols_from_command_line()
2151 {
2152 if (parameters->options().any_undefined())
2153 {
2154 if (parameters->target().get_size() == 32)
2155 {
2156 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2157 this->do_add_undefined_symbols_from_command_line<32>();
2158 #else
2159 gold_unreachable();
2160 #endif
2161 }
2162 else if (parameters->target().get_size() == 64)
2163 {
2164 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2165 this->do_add_undefined_symbols_from_command_line<64>();
2166 #else
2167 gold_unreachable();
2168 #endif
2169 }
2170 else
2171 gold_unreachable();
2172 }
2173 }
2174
2175 template<int size>
2176 void
2177 Symbol_table::do_add_undefined_symbols_from_command_line()
2178 {
2179 for (options::String_set::const_iterator p =
2180 parameters->options().undefined_begin();
2181 p != parameters->options().undefined_end();
2182 ++p)
2183 {
2184 const char* name = p->c_str();
2185
2186 if (this->lookup(name) != NULL)
2187 continue;
2188
2189 const char* version = NULL;
2190
2191 Sized_symbol<size>* sym;
2192 Sized_symbol<size>* oldsym;
2193 bool resolve_oldsym;
2194 if (parameters->target().is_big_endian())
2195 {
2196 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
2197 sym = this->define_special_symbol<size, true>(&name, &version,
2198 false, &oldsym,
2199 &resolve_oldsym);
2200 #else
2201 gold_unreachable();
2202 #endif
2203 }
2204 else
2205 {
2206 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
2207 sym = this->define_special_symbol<size, false>(&name, &version,
2208 false, &oldsym,
2209 &resolve_oldsym);
2210 #else
2211 gold_unreachable();
2212 #endif
2213 }
2214
2215 gold_assert(oldsym == NULL);
2216
2217 sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
2218 elfcpp::STV_DEFAULT, 0);
2219 ++this->saw_undefined_;
2220 }
2221 }
2222
2223 // Set the dynamic symbol indexes. INDEX is the index of the first
2224 // global dynamic symbol. Pointers to the symbols are stored into the
2225 // vector SYMS. The names are added to DYNPOOL. This returns an
2226 // updated dynamic symbol index.
2227
2228 unsigned int
2229 Symbol_table::set_dynsym_indexes(unsigned int index,
2230 std::vector<Symbol*>* syms,
2231 Stringpool* dynpool,
2232 Versions* versions)
2233 {
2234 for (Symbol_table_type::iterator p = this->table_.begin();
2235 p != this->table_.end();
2236 ++p)
2237 {
2238 Symbol* sym = p->second;
2239
2240 // Note that SYM may already have a dynamic symbol index, since
2241 // some symbols appear more than once in the symbol table, with
2242 // and without a version.
2243
2244 if (!sym->should_add_dynsym_entry())
2245 sym->set_dynsym_index(-1U);
2246 else if (!sym->has_dynsym_index())
2247 {
2248 sym->set_dynsym_index(index);
2249 ++index;
2250 syms->push_back(sym);
2251 dynpool->add(sym->name(), false, NULL);
2252
2253 // Record any version information.
2254 if (sym->version() != NULL)
2255 versions->record_version(this, dynpool, sym);
2256
2257 // If the symbol is defined in a dynamic object and is
2258 // referenced in a regular object, then mark the dynamic
2259 // object as needed. This is used to implement --as-needed.
2260 if (sym->is_from_dynobj() && sym->in_reg())
2261 sym->object()->set_is_needed();
2262 }
2263 }
2264
2265 // Finish up the versions. In some cases this may add new dynamic
2266 // symbols.
2267 index = versions->finalize(this, index, syms);
2268
2269 return index;
2270 }
2271
2272 // Set the final values for all the symbols. The index of the first
2273 // global symbol in the output file is *PLOCAL_SYMCOUNT. Record the
2274 // file offset OFF. Add their names to POOL. Return the new file
2275 // offset. Update *PLOCAL_SYMCOUNT if necessary.
2276
2277 off_t
2278 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
2279 size_t dyncount, Stringpool* pool,
2280 unsigned int *plocal_symcount)
2281 {
2282 off_t ret;
2283
2284 gold_assert(*plocal_symcount != 0);
2285 this->first_global_index_ = *plocal_symcount;
2286
2287 this->dynamic_offset_ = dynoff;
2288 this->first_dynamic_global_index_ = dyn_global_index;
2289 this->dynamic_count_ = dyncount;
2290
2291 if (parameters->target().get_size() == 32)
2292 {
2293 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
2294 ret = this->sized_finalize<32>(off, pool, plocal_symcount);
2295 #else
2296 gold_unreachable();
2297 #endif
2298 }
2299 else if (parameters->target().get_size() == 64)
2300 {
2301 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
2302 ret = this->sized_finalize<64>(off, pool, plocal_symcount);
2303 #else
2304 gold_unreachable();
2305 #endif
2306 }
2307 else
2308 gold_unreachable();
2309
2310 // Now that we have the final symbol table, we can reliably note
2311 // which symbols should get warnings.
2312 this->warnings_.note_warnings(this);
2313
2314 return ret;
2315 }
2316
2317 // SYM is going into the symbol table at *PINDEX. Add the name to
2318 // POOL, update *PINDEX and *POFF.
2319
2320 template<int size>
2321 void
2322 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
2323 unsigned int* pindex, off_t* poff)
2324 {
2325 sym->set_symtab_index(*pindex);
2326 pool->add(sym->name(), false, NULL);
2327 ++*pindex;
2328 *poff += elfcpp::Elf_sizes<size>::sym_size;
2329 }
2330
2331 // Set the final value for all the symbols. This is called after
2332 // Layout::finalize, so all the output sections have their final
2333 // address.
2334
2335 template<int size>
2336 off_t
2337 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
2338 unsigned int* plocal_symcount)
2339 {
2340 off = align_address(off, size >> 3);
2341 this->offset_ = off;
2342
2343 unsigned int index = *plocal_symcount;
2344 const unsigned int orig_index = index;
2345
2346 // First do all the symbols which have been forced to be local, as
2347 // they must appear before all global symbols.
2348 for (Forced_locals::iterator p = this->forced_locals_.begin();
2349 p != this->forced_locals_.end();
2350 ++p)
2351 {
2352 Symbol* sym = *p;
2353 gold_assert(sym->is_forced_local());
2354 if (this->sized_finalize_symbol<size>(sym))
2355 {
2356 this->add_to_final_symtab<size>(sym, pool, &index, &off);
2357 ++*plocal_symcount;
2358 }
2359 }
2360
2361 // Now do all the remaining symbols.
2362 for (Symbol_table_type::iterator p = this->table_.begin();
2363 p != this->table_.end();
2364 ++p)
2365 {
2366 Symbol* sym = p->second;
2367 if (this->sized_finalize_symbol<size>(sym))
2368 this->add_to_final_symtab<size>(sym, pool, &index, &off);
2369 }
2370
2371 this->output_count_ = index - orig_index;
2372
2373 return off;
2374 }
2375
2376 // Compute the final value of SYM and store status in location PSTATUS.
2377 // During relaxation, this may be called multiple times for a symbol to
2378 // compute its would-be final value in each relaxation pass.
2379
2380 template<int size>
2381 typename Sized_symbol<size>::Value_type
2382 Symbol_table::compute_final_value(
2383 const Sized_symbol<size>* sym,
2384 Compute_final_value_status* pstatus) const
2385 {
2386 typedef typename Sized_symbol<size>::Value_type Value_type;
2387 Value_type value;
2388
2389 switch (sym->source())
2390 {
2391 case Symbol::FROM_OBJECT:
2392 {
2393 bool is_ordinary;
2394 unsigned int shndx = sym->shndx(&is_ordinary);
2395
2396 if (!is_ordinary
2397 && shndx != elfcpp::SHN_ABS
2398 && !Symbol::is_common_shndx(shndx))
2399 {
2400 *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION;
2401 return 0;
2402 }
2403
2404 Object* symobj = sym->object();
2405 if (symobj->is_dynamic())
2406 {
2407 value = 0;
2408 shndx = elfcpp::SHN_UNDEF;
2409 }
2410 else if (symobj->pluginobj() != NULL)
2411 {
2412 value = 0;
2413 shndx = elfcpp::SHN_UNDEF;
2414 }
2415 else if (shndx == elfcpp::SHN_UNDEF)
2416 value = 0;
2417 else if (!is_ordinary
2418 && (shndx == elfcpp::SHN_ABS
2419 || Symbol::is_common_shndx(shndx)))
2420 value = sym->value();
2421 else
2422 {
2423 Relobj* relobj = static_cast<Relobj*>(symobj);
2424 Output_section* os = relobj->output_section(shndx);
2425
2426 if (this->is_section_folded(relobj, shndx))
2427 {
2428 gold_assert(os == NULL);
2429 // Get the os of the section it is folded onto.
2430 Section_id folded = this->icf_->get_folded_section(relobj,
2431 shndx);
2432 gold_assert(folded.first != NULL);
2433 Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first);
2434 unsigned folded_shndx = folded.second;
2435
2436 os = folded_obj->output_section(folded_shndx);
2437 gold_assert(os != NULL);
2438
2439 // Replace (relobj, shndx) with canonical ICF input section.
2440 shndx = folded_shndx;
2441 relobj = folded_obj;
2442 }
2443
2444 uint64_t secoff64 = relobj->output_section_offset(shndx);
2445 if (os == NULL)
2446 {
2447 bool static_or_reloc = (parameters->doing_static_link() ||
2448 parameters->options().relocatable());
2449 gold_assert(static_or_reloc || sym->dynsym_index() == -1U);
2450
2451 *pstatus = CFVS_NO_OUTPUT_SECTION;
2452 return 0;
2453 }
2454
2455 if (secoff64 == -1ULL)
2456 {
2457 // The section needs special handling (e.g., a merge section).
2458
2459 value = os->output_address(relobj, shndx, sym->value());
2460 }
2461 else
2462 {
2463 Value_type secoff =
2464 convert_types<Value_type, uint64_t>(secoff64);
2465 if (sym->type() == elfcpp::STT_TLS)
2466 value = sym->value() + os->tls_offset() + secoff;
2467 else
2468 value = sym->value() + os->address() + secoff;
2469 }
2470 }
2471 }
2472 break;
2473
2474 case Symbol::IN_OUTPUT_DATA:
2475 {
2476 Output_data* od = sym->output_data();
2477 value = sym->value();
2478 if (sym->type() != elfcpp::STT_TLS)
2479 value += od->address();
2480 else
2481 {
2482 Output_section* os = od->output_section();
2483 gold_assert(os != NULL);
2484 value += os->tls_offset() + (od->address() - os->address());
2485 }
2486 if (sym->offset_is_from_end())
2487 value += od->data_size();
2488 }
2489 break;
2490
2491 case Symbol::IN_OUTPUT_SEGMENT:
2492 {
2493 Output_segment* os = sym->output_segment();
2494 value = sym->value();
2495 if (sym->type() != elfcpp::STT_TLS)
2496 value += os->vaddr();
2497 switch (sym->offset_base())
2498 {
2499 case Symbol::SEGMENT_START:
2500 break;
2501 case Symbol::SEGMENT_END:
2502 value += os->memsz();
2503 break;
2504 case Symbol::SEGMENT_BSS:
2505 value += os->filesz();
2506 break;
2507 default:
2508 gold_unreachable();
2509 }
2510 }
2511 break;
2512
2513 case Symbol::IS_CONSTANT:
2514 value = sym->value();
2515 break;
2516
2517 case Symbol::IS_UNDEFINED:
2518 value = 0;
2519 break;
2520
2521 default:
2522 gold_unreachable();
2523 }
2524
2525 *pstatus = CFVS_OK;
2526 return value;
2527 }
2528
2529 // Finalize the symbol SYM. This returns true if the symbol should be
2530 // added to the symbol table, false otherwise.
2531
2532 template<int size>
2533 bool
2534 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
2535 {
2536 typedef typename Sized_symbol<size>::Value_type Value_type;
2537
2538 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
2539
2540 // The default version of a symbol may appear twice in the symbol
2541 // table. We only need to finalize it once.
2542 if (sym->has_symtab_index())
2543 return false;
2544
2545 if (!sym->in_reg())
2546 {
2547 gold_assert(!sym->has_symtab_index());
2548 sym->set_symtab_index(-1U);
2549 gold_assert(sym->dynsym_index() == -1U);
2550 return false;
2551 }
2552
2553 // Compute final symbol value.
2554 Compute_final_value_status status;
2555 Value_type value = this->compute_final_value(sym, &status);
2556
2557 switch (status)
2558 {
2559 case CFVS_OK:
2560 break;
2561 case CFVS_UNSUPPORTED_SYMBOL_SECTION:
2562 {
2563 bool is_ordinary;
2564 unsigned int shndx = sym->shndx(&is_ordinary);
2565 gold_error(_("%s: unsupported symbol section 0x%x"),
2566 sym->demangled_name().c_str(), shndx);
2567 }
2568 break;
2569 case CFVS_NO_OUTPUT_SECTION:
2570 sym->set_symtab_index(-1U);
2571 return false;
2572 default:
2573 gold_unreachable();
2574 }
2575
2576 sym->set_value(value);
2577
2578 if (parameters->options().strip_all()
2579 || !parameters->options().should_retain_symbol(sym->name()))
2580 {
2581 sym->set_symtab_index(-1U);
2582 return false;
2583 }
2584
2585 return true;
2586 }
2587
2588 // Write out the global symbols.
2589
2590 void
2591 Symbol_table::write_globals(const Stringpool* sympool,
2592 const Stringpool* dynpool,
2593 Output_symtab_xindex* symtab_xindex,
2594 Output_symtab_xindex* dynsym_xindex,
2595 Output_file* of) const
2596 {
2597 switch (parameters->size_and_endianness())
2598 {
2599 #ifdef HAVE_TARGET_32_LITTLE
2600 case Parameters::TARGET_32_LITTLE:
2601 this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex,
2602 dynsym_xindex, of);
2603 break;
2604 #endif
2605 #ifdef HAVE_TARGET_32_BIG
2606 case Parameters::TARGET_32_BIG:
2607 this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex,
2608 dynsym_xindex, of);
2609 break;
2610 #endif
2611 #ifdef HAVE_TARGET_64_LITTLE
2612 case Parameters::TARGET_64_LITTLE:
2613 this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex,
2614 dynsym_xindex, of);
2615 break;
2616 #endif
2617 #ifdef HAVE_TARGET_64_BIG
2618 case Parameters::TARGET_64_BIG:
2619 this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex,
2620 dynsym_xindex, of);
2621 break;
2622 #endif
2623 default:
2624 gold_unreachable();
2625 }
2626 }
2627
2628 // Write out the global symbols.
2629
2630 template<int size, bool big_endian>
2631 void
2632 Symbol_table::sized_write_globals(const Stringpool* sympool,
2633 const Stringpool* dynpool,
2634 Output_symtab_xindex* symtab_xindex,
2635 Output_symtab_xindex* dynsym_xindex,
2636 Output_file* of) const
2637 {
2638 const Target& target = parameters->target();
2639
2640 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2641
2642 const unsigned int output_count = this->output_count_;
2643 const section_size_type oview_size = output_count * sym_size;
2644 const unsigned int first_global_index = this->first_global_index_;
2645 unsigned char* psyms;
2646 if (this->offset_ == 0 || output_count == 0)
2647 psyms = NULL;
2648 else
2649 psyms = of->get_output_view(this->offset_, oview_size);
2650
2651 const unsigned int dynamic_count = this->dynamic_count_;
2652 const section_size_type dynamic_size = dynamic_count * sym_size;
2653 const unsigned int first_dynamic_global_index =
2654 this->first_dynamic_global_index_;
2655 unsigned char* dynamic_view;
2656 if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2657 dynamic_view = NULL;
2658 else
2659 dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2660
2661 for (Symbol_table_type::const_iterator p = this->table_.begin();
2662 p != this->table_.end();
2663 ++p)
2664 {
2665 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2666
2667 // Possibly warn about unresolved symbols in shared libraries.
2668 this->warn_about_undefined_dynobj_symbol(sym);
2669
2670 unsigned int sym_index = sym->symtab_index();
2671 unsigned int dynsym_index;
2672 if (dynamic_view == NULL)
2673 dynsym_index = -1U;
2674 else
2675 dynsym_index = sym->dynsym_index();
2676
2677 if (sym_index == -1U && dynsym_index == -1U)
2678 {
2679 // This symbol is not included in the output file.
2680 continue;
2681 }
2682
2683 unsigned int shndx;
2684 typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2685 typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2686 switch (sym->source())
2687 {
2688 case Symbol::FROM_OBJECT:
2689 {
2690 bool is_ordinary;
2691 unsigned int in_shndx = sym->shndx(&is_ordinary);
2692
2693 if (!is_ordinary
2694 && in_shndx != elfcpp::SHN_ABS
2695 && !Symbol::is_common_shndx(in_shndx))
2696 {
2697 gold_error(_("%s: unsupported symbol section 0x%x"),
2698 sym->demangled_name().c_str(), in_shndx);
2699 shndx = in_shndx;
2700 }
2701 else
2702 {
2703 Object* symobj = sym->object();
2704 if (symobj->is_dynamic())
2705 {
2706 if (sym->needs_dynsym_value())
2707 dynsym_value = target.dynsym_value(sym);
2708 shndx = elfcpp::SHN_UNDEF;
2709 }
2710 else if (symobj->pluginobj() != NULL)
2711 shndx = elfcpp::SHN_UNDEF;
2712 else if (in_shndx == elfcpp::SHN_UNDEF
2713 || (!is_ordinary
2714 && (in_shndx == elfcpp::SHN_ABS
2715 || Symbol::is_common_shndx(in_shndx))))
2716 shndx = in_shndx;
2717 else
2718 {
2719 Relobj* relobj = static_cast<Relobj*>(symobj);
2720 Output_section* os = relobj->output_section(in_shndx);
2721 if (this->is_section_folded(relobj, in_shndx))
2722 {
2723 // This global symbol must be written out even though
2724 // it is folded.
2725 // Get the os of the section it is folded onto.
2726 Section_id folded =
2727 this->icf_->get_folded_section(relobj, in_shndx);
2728 gold_assert(folded.first !=NULL);
2729 Relobj* folded_obj =
2730 reinterpret_cast<Relobj*>(folded.first);
2731 os = folded_obj->output_section(folded.second);
2732 gold_assert(os != NULL);
2733 }
2734 gold_assert(os != NULL);
2735 shndx = os->out_shndx();
2736
2737 if (shndx >= elfcpp::SHN_LORESERVE)
2738 {
2739 if (sym_index != -1U)
2740 symtab_xindex->add(sym_index, shndx);
2741 if (dynsym_index != -1U)
2742 dynsym_xindex->add(dynsym_index, shndx);
2743 shndx = elfcpp::SHN_XINDEX;
2744 }
2745
2746 // In object files symbol values are section
2747 // relative.
2748 if (parameters->options().relocatable())
2749 sym_value -= os->address();
2750 }
2751 }
2752 }
2753 break;
2754
2755 case Symbol::IN_OUTPUT_DATA:
2756 shndx = sym->output_data()->out_shndx();
2757 if (shndx >= elfcpp::SHN_LORESERVE)
2758 {
2759 if (sym_index != -1U)
2760 symtab_xindex->add(sym_index, shndx);
2761 if (dynsym_index != -1U)
2762 dynsym_xindex->add(dynsym_index, shndx);
2763 shndx = elfcpp::SHN_XINDEX;
2764 }
2765 break;
2766
2767 case Symbol::IN_OUTPUT_SEGMENT:
2768 shndx = elfcpp::SHN_ABS;
2769 break;
2770
2771 case Symbol::IS_CONSTANT:
2772 shndx = elfcpp::SHN_ABS;
2773 break;
2774
2775 case Symbol::IS_UNDEFINED:
2776 shndx = elfcpp::SHN_UNDEF;
2777 break;
2778
2779 default:
2780 gold_unreachable();
2781 }
2782
2783 if (sym_index != -1U)
2784 {
2785 sym_index -= first_global_index;
2786 gold_assert(sym_index < output_count);
2787 unsigned char* ps = psyms + (sym_index * sym_size);
2788 this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2789 sympool, ps);
2790 }
2791
2792 if (dynsym_index != -1U)
2793 {
2794 dynsym_index -= first_dynamic_global_index;
2795 gold_assert(dynsym_index < dynamic_count);
2796 unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2797 this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2798 dynpool, pd);
2799 }
2800 }
2801
2802 of->write_output_view(this->offset_, oview_size, psyms);
2803 if (dynamic_view != NULL)
2804 of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2805 }
2806
2807 // Write out the symbol SYM, in section SHNDX, to P. POOL is the
2808 // strtab holding the name.
2809
2810 template<int size, bool big_endian>
2811 void
2812 Symbol_table::sized_write_symbol(
2813 Sized_symbol<size>* sym,
2814 typename elfcpp::Elf_types<size>::Elf_Addr value,
2815 unsigned int shndx,
2816 const Stringpool* pool,
2817 unsigned char* p) const
2818 {
2819 elfcpp::Sym_write<size, big_endian> osym(p);
2820 osym.put_st_name(pool->get_offset(sym->name()));
2821 osym.put_st_value(value);
2822 // Use a symbol size of zero for undefined symbols from shared libraries.
2823 if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj())
2824 osym.put_st_size(0);
2825 else
2826 osym.put_st_size(sym->symsize());
2827 elfcpp::STT type = sym->type();
2828 // Turn IFUNC symbols from shared libraries into normal FUNC symbols.
2829 if (type == elfcpp::STT_GNU_IFUNC
2830 && sym->is_from_dynobj())
2831 type = elfcpp::STT_FUNC;
2832 // A version script may have overridden the default binding.
2833 if (sym->is_forced_local())
2834 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type));
2835 else
2836 osym.put_st_info(elfcpp::elf_st_info(sym->binding(), type));
2837 osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2838 osym.put_st_shndx(shndx);
2839 }
2840
2841 // Check for unresolved symbols in shared libraries. This is
2842 // controlled by the --allow-shlib-undefined option.
2843
2844 // We only warn about libraries for which we have seen all the
2845 // DT_NEEDED entries. We don't try to track down DT_NEEDED entries
2846 // which were not seen in this link. If we didn't see a DT_NEEDED
2847 // entry, we aren't going to be able to reliably report whether the
2848 // symbol is undefined.
2849
2850 // We also don't warn about libraries found in a system library
2851 // directory (e.g., /lib or /usr/lib); we assume that those libraries
2852 // are OK. This heuristic avoids problems on GNU/Linux, in which -ldl
2853 // can have undefined references satisfied by ld-linux.so.
2854
2855 inline void
2856 Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const
2857 {
2858 bool dummy;
2859 if (sym->source() == Symbol::FROM_OBJECT
2860 && sym->object()->is_dynamic()
2861 && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2862 && sym->binding() != elfcpp::STB_WEAK
2863 && !parameters->options().allow_shlib_undefined()
2864 && !parameters->target().is_defined_by_abi(sym)
2865 && !sym->object()->is_in_system_directory())
2866 {
2867 // A very ugly cast.
2868 Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2869 if (!dynobj->has_unknown_needed_entries())
2870 gold_undefined_symbol(sym);
2871 }
2872 }
2873
2874 // Write out a section symbol. Return the update offset.
2875
2876 void
2877 Symbol_table::write_section_symbol(const Output_section *os,
2878 Output_symtab_xindex* symtab_xindex,
2879 Output_file* of,
2880 off_t offset) const
2881 {
2882 switch (parameters->size_and_endianness())
2883 {
2884 #ifdef HAVE_TARGET_32_LITTLE
2885 case Parameters::TARGET_32_LITTLE:
2886 this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2887 offset);
2888 break;
2889 #endif
2890 #ifdef HAVE_TARGET_32_BIG
2891 case Parameters::TARGET_32_BIG:
2892 this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2893 offset);
2894 break;
2895 #endif
2896 #ifdef HAVE_TARGET_64_LITTLE
2897 case Parameters::TARGET_64_LITTLE:
2898 this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2899 offset);
2900 break;
2901 #endif
2902 #ifdef HAVE_TARGET_64_BIG
2903 case Parameters::TARGET_64_BIG:
2904 this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2905 offset);
2906 break;
2907 #endif
2908 default:
2909 gold_unreachable();
2910 }
2911 }
2912
2913 // Write out a section symbol, specialized for size and endianness.
2914
2915 template<int size, bool big_endian>
2916 void
2917 Symbol_table::sized_write_section_symbol(const Output_section* os,
2918 Output_symtab_xindex* symtab_xindex,
2919 Output_file* of,
2920 off_t offset) const
2921 {
2922 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2923
2924 unsigned char* pov = of->get_output_view(offset, sym_size);
2925
2926 elfcpp::Sym_write<size, big_endian> osym(pov);
2927 osym.put_st_name(0);
2928 if (parameters->options().relocatable())
2929 osym.put_st_value(0);
2930 else
2931 osym.put_st_value(os->address());
2932 osym.put_st_size(0);
2933 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2934 elfcpp::STT_SECTION));
2935 osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2936
2937 unsigned int shndx = os->out_shndx();
2938 if (shndx >= elfcpp::SHN_LORESERVE)
2939 {
2940 symtab_xindex->add(os->symtab_index(), shndx);
2941 shndx = elfcpp::SHN_XINDEX;
2942 }
2943 osym.put_st_shndx(shndx);
2944
2945 of->write_output_view(offset, sym_size, pov);
2946 }
2947
2948 // Print statistical information to stderr. This is used for --stats.
2949
2950 void
2951 Symbol_table::print_stats() const
2952 {
2953 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2954 fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2955 program_name, this->table_.size(), this->table_.bucket_count());
2956 #else
2957 fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2958 program_name, this->table_.size());
2959 #endif
2960 this->namepool_.print_stats("symbol table stringpool");
2961 }
2962
2963 // We check for ODR violations by looking for symbols with the same
2964 // name for which the debugging information reports that they were
2965 // defined in different source locations. When comparing the source
2966 // location, we consider instances with the same base filename and
2967 // line number to be the same. This is because different object
2968 // files/shared libraries can include the same header file using
2969 // different paths, and we don't want to report an ODR violation in
2970 // that case.
2971
2972 // This struct is used to compare line information, as returned by
2973 // Dwarf_line_info::one_addr2line. It implements a < comparison
2974 // operator used with std::set.
2975
2976 struct Odr_violation_compare
2977 {
2978 bool
2979 operator()(const std::string& s1, const std::string& s2) const
2980 {
2981 std::string::size_type pos1 = s1.rfind('/');
2982 std::string::size_type pos2 = s2.rfind('/');
2983 if (pos1 == std::string::npos
2984 || pos2 == std::string::npos)
2985 return s1 < s2;
2986 return s1.compare(pos1, std::string::npos,
2987 s2, pos2, std::string::npos) < 0;
2988 }
2989 };
2990
2991 // Check candidate_odr_violations_ to find symbols with the same name
2992 // but apparently different definitions (different source-file/line-no).
2993
2994 void
2995 Symbol_table::detect_odr_violations(const Task* task,
2996 const char* output_file_name) const
2997 {
2998 for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2999 it != candidate_odr_violations_.end();
3000 ++it)
3001 {
3002 const char* symbol_name = it->first;
3003 // We use a sorted set so the output is deterministic.
3004 std::set<std::string, Odr_violation_compare> line_nums;
3005
3006 for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
3007 locs = it->second.begin();
3008 locs != it->second.end();
3009 ++locs)
3010 {
3011 // We need to lock the object in order to read it. This
3012 // means that we have to run in a singleton Task. If we
3013 // want to run this in a general Task for better
3014 // performance, we will need one Task for object, plus
3015 // appropriate locking to ensure that we don't conflict with
3016 // other uses of the object. Also note, one_addr2line is not
3017 // currently thread-safe.
3018 Task_lock_obj<Object> tl(task, locs->object);
3019 // 16 is the size of the object-cache that one_addr2line should use.
3020 std::string lineno = Dwarf_line_info::one_addr2line(
3021 locs->object, locs->shndx, locs->offset, 16);
3022 if (!lineno.empty())
3023 line_nums.insert(lineno);
3024 }
3025
3026 if (line_nums.size() > 1)
3027 {
3028 gold_warning(_("while linking %s: symbol '%s' defined in multiple "
3029 "places (possible ODR violation):"),
3030 output_file_name, demangle(symbol_name).c_str());
3031 for (std::set<std::string>::const_iterator it2 = line_nums.begin();
3032 it2 != line_nums.end();
3033 ++it2)
3034 fprintf(stderr, " %s\n", it2->c_str());
3035 }
3036 }
3037 // We only call one_addr2line() in this function, so we can clear its cache.
3038 Dwarf_line_info::clear_addr2line_cache();
3039 }
3040
3041 // Warnings functions.
3042
3043 // Add a new warning.
3044
3045 void
3046 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
3047 const std::string& warning)
3048 {
3049 name = symtab->canonicalize_name(name);
3050 this->warnings_[name].set(obj, warning);
3051 }
3052
3053 // Look through the warnings and mark the symbols for which we should
3054 // warn. This is called during Layout::finalize when we know the
3055 // sources for all the symbols.
3056
3057 void
3058 Warnings::note_warnings(Symbol_table* symtab)
3059 {
3060 for (Warning_table::iterator p = this->warnings_.begin();
3061 p != this->warnings_.end();
3062 ++p)
3063 {
3064 Symbol* sym = symtab->lookup(p->first, NULL);
3065 if (sym != NULL
3066 && sym->source() == Symbol::FROM_OBJECT
3067 && sym->object() == p->second.object)
3068 sym->set_has_warning();
3069 }
3070 }
3071
3072 // Issue a warning. This is called when we see a relocation against a
3073 // symbol for which has a warning.
3074
3075 template<int size, bool big_endian>
3076 void
3077 Warnings::issue_warning(const Symbol* sym,
3078 const Relocate_info<size, big_endian>* relinfo,
3079 size_t relnum, off_t reloffset) const
3080 {
3081 gold_assert(sym->has_warning());
3082 Warning_table::const_iterator p = this->warnings_.find(sym->name());
3083 gold_assert(p != this->warnings_.end());
3084 gold_warning_at_location(relinfo, relnum, reloffset,
3085 "%s", p->second.text.c_str());
3086 }
3087
3088 // Instantiate the templates we need. We could use the configure
3089 // script to restrict this to only the ones needed for implemented
3090 // targets.
3091
3092 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3093 template
3094 void
3095 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
3096 #endif
3097
3098 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3099 template
3100 void
3101 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
3102 #endif
3103
3104 #ifdef HAVE_TARGET_32_LITTLE
3105 template
3106 void
3107 Symbol_table::add_from_relobj<32, false>(
3108 Sized_relobj<32, false>* relobj,
3109 const unsigned char* syms,
3110 size_t count,
3111 size_t symndx_offset,
3112 const char* sym_names,
3113 size_t sym_name_size,
3114 Sized_relobj<32, false>::Symbols* sympointers,
3115 size_t* defined);
3116 #endif
3117
3118 #ifdef HAVE_TARGET_32_BIG
3119 template
3120 void
3121 Symbol_table::add_from_relobj<32, true>(
3122 Sized_relobj<32, true>* relobj,
3123 const unsigned char* syms,
3124 size_t count,
3125 size_t symndx_offset,
3126 const char* sym_names,
3127 size_t sym_name_size,
3128 Sized_relobj<32, true>::Symbols* sympointers,
3129 size_t* defined);
3130 #endif
3131
3132 #ifdef HAVE_TARGET_64_LITTLE
3133 template
3134 void
3135 Symbol_table::add_from_relobj<64, false>(
3136 Sized_relobj<64, false>* relobj,
3137 const unsigned char* syms,
3138 size_t count,
3139 size_t symndx_offset,
3140 const char* sym_names,
3141 size_t sym_name_size,
3142 Sized_relobj<64, false>::Symbols* sympointers,
3143 size_t* defined);
3144 #endif
3145
3146 #ifdef HAVE_TARGET_64_BIG
3147 template
3148 void
3149 Symbol_table::add_from_relobj<64, true>(
3150 Sized_relobj<64, true>* relobj,
3151 const unsigned char* syms,
3152 size_t count,
3153 size_t symndx_offset,
3154 const char* sym_names,
3155 size_t sym_name_size,
3156 Sized_relobj<64, true>::Symbols* sympointers,
3157 size_t* defined);
3158 #endif
3159
3160 #ifdef HAVE_TARGET_32_LITTLE
3161 template
3162 Symbol*
3163 Symbol_table::add_from_pluginobj<32, false>(
3164 Sized_pluginobj<32, false>* obj,
3165 const char* name,
3166 const char* ver,
3167 elfcpp::Sym<32, false>* sym);
3168 #endif
3169
3170 #ifdef HAVE_TARGET_32_BIG
3171 template
3172 Symbol*
3173 Symbol_table::add_from_pluginobj<32, true>(
3174 Sized_pluginobj<32, true>* obj,
3175 const char* name,
3176 const char* ver,
3177 elfcpp::Sym<32, true>* sym);
3178 #endif
3179
3180 #ifdef HAVE_TARGET_64_LITTLE
3181 template
3182 Symbol*
3183 Symbol_table::add_from_pluginobj<64, false>(
3184 Sized_pluginobj<64, false>* obj,
3185 const char* name,
3186 const char* ver,
3187 elfcpp::Sym<64, false>* sym);
3188 #endif
3189
3190 #ifdef HAVE_TARGET_64_BIG
3191 template
3192 Symbol*
3193 Symbol_table::add_from_pluginobj<64, true>(
3194 Sized_pluginobj<64, true>* obj,
3195 const char* name,
3196 const char* ver,
3197 elfcpp::Sym<64, true>* sym);
3198 #endif
3199
3200 #ifdef HAVE_TARGET_32_LITTLE
3201 template
3202 void
3203 Symbol_table::add_from_dynobj<32, false>(
3204 Sized_dynobj<32, false>* dynobj,
3205 const unsigned char* syms,
3206 size_t count,
3207 const char* sym_names,
3208 size_t sym_name_size,
3209 const unsigned char* versym,
3210 size_t versym_size,
3211 const std::vector<const char*>* version_map,
3212 Sized_relobj<32, false>::Symbols* sympointers,
3213 size_t* defined);
3214 #endif
3215
3216 #ifdef HAVE_TARGET_32_BIG
3217 template
3218 void
3219 Symbol_table::add_from_dynobj<32, true>(
3220 Sized_dynobj<32, true>* dynobj,
3221 const unsigned char* syms,
3222 size_t count,
3223 const char* sym_names,
3224 size_t sym_name_size,
3225 const unsigned char* versym,
3226 size_t versym_size,
3227 const std::vector<const char*>* version_map,
3228 Sized_relobj<32, true>::Symbols* sympointers,
3229 size_t* defined);
3230 #endif
3231
3232 #ifdef HAVE_TARGET_64_LITTLE
3233 template
3234 void
3235 Symbol_table::add_from_dynobj<64, false>(
3236 Sized_dynobj<64, false>* dynobj,
3237 const unsigned char* syms,
3238 size_t count,
3239 const char* sym_names,
3240 size_t sym_name_size,
3241 const unsigned char* versym,
3242 size_t versym_size,
3243 const std::vector<const char*>* version_map,
3244 Sized_relobj<64, false>::Symbols* sympointers,
3245 size_t* defined);
3246 #endif
3247
3248 #ifdef HAVE_TARGET_64_BIG
3249 template
3250 void
3251 Symbol_table::add_from_dynobj<64, true>(
3252 Sized_dynobj<64, true>* dynobj,
3253 const unsigned char* syms,
3254 size_t count,
3255 const char* sym_names,
3256 size_t sym_name_size,
3257 const unsigned char* versym,
3258 size_t versym_size,
3259 const std::vector<const char*>* version_map,
3260 Sized_relobj<64, true>::Symbols* sympointers,
3261 size_t* defined);
3262 #endif
3263
3264 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
3265 template
3266 void
3267 Symbol_table::define_with_copy_reloc<32>(
3268 Sized_symbol<32>* sym,
3269 Output_data* posd,
3270 elfcpp::Elf_types<32>::Elf_Addr value);
3271 #endif
3272
3273 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
3274 template
3275 void
3276 Symbol_table::define_with_copy_reloc<64>(
3277 Sized_symbol<64>* sym,
3278 Output_data* posd,
3279 elfcpp::Elf_types<64>::Elf_Addr value);
3280 #endif
3281
3282 #ifdef HAVE_TARGET_32_LITTLE
3283 template
3284 void
3285 Warnings::issue_warning<32, false>(const Symbol* sym,
3286 const Relocate_info<32, false>* relinfo,
3287 size_t relnum, off_t reloffset) const;
3288 #endif
3289
3290 #ifdef HAVE_TARGET_32_BIG
3291 template
3292 void
3293 Warnings::issue_warning<32, true>(const Symbol* sym,
3294 const Relocate_info<32, true>* relinfo,
3295 size_t relnum, off_t reloffset) const;
3296 #endif
3297
3298 #ifdef HAVE_TARGET_64_LITTLE
3299 template
3300 void
3301 Warnings::issue_warning<64, false>(const Symbol* sym,
3302 const Relocate_info<64, false>* relinfo,
3303 size_t relnum, off_t reloffset) const;
3304 #endif
3305
3306 #ifdef HAVE_TARGET_64_BIG
3307 template
3308 void
3309 Warnings::issue_warning<64, true>(const Symbol* sym,
3310 const Relocate_info<64, true>* relinfo,
3311 size_t relnum, off_t reloffset) const;
3312 #endif
3313
3314 } // End namespace gold.
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