1 // resolve.cc -- symbol resolution for gold
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
34 // Symbol methods used in this file.
36 // This symbol is being overridden by another symbol whose version is
37 // VERSION. Update the VERSION_ field accordingly.
40 Symbol::override_version(const char* version)
44 // This is the case where this symbol is NAME/VERSION, and the
45 // version was not marked as hidden. That makes it the default
46 // version, so we create NAME/NULL. Later we see another symbol
47 // NAME/NULL, and that symbol is overriding this one. In this
48 // case, since NAME/VERSION is the default, we make NAME/NULL
49 // override NAME/VERSION as well. They are already the same
50 // Symbol structure. Setting the VERSION_ field to NULL ensures
51 // that it will be output with the correct, empty, version.
52 this->version_ = version;
56 // This is the case where this symbol is NAME/VERSION_ONE, and
57 // now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is
58 // overriding NAME. If VERSION_ONE and VERSION_TWO are
59 // different, then this can only happen when VERSION_ONE is NULL
60 // and VERSION_TWO is not hidden.
61 gold_assert(this->version_ == version || this->version_ == NULL);
62 this->version_ = version;
66 // This symbol is being overidden by another symbol whose visibility
67 // is VISIBILITY. Updated the VISIBILITY_ field accordingly.
70 Symbol::override_visibility(elfcpp::STV visibility)
72 // The rule for combining visibility is that we always choose the
73 // most constrained visibility. In order of increasing constraint,
74 // visibility goes PROTECTED, HIDDEN, INTERNAL. This is the reverse
75 // of the numeric values, so the effect is that we always want the
76 // smallest non-zero value.
77 if (visibility != elfcpp::STV_DEFAULT)
79 if (this->visibility_ == elfcpp::STV_DEFAULT)
80 this->visibility_ = visibility;
81 else if (this->visibility_ > visibility)
82 this->visibility_ = visibility;
86 // Override the fields in Symbol.
88 template<int size, bool big_endian>
90 Symbol::override_base(const elfcpp::Sym<size, big_endian>& sym,
91 unsigned int st_shndx, bool is_ordinary,
92 Object* object, const char* version)
94 gold_assert(this->source_ == FROM_OBJECT);
95 this->u_.from_object.object = object;
96 this->override_version(version);
97 this->u_.from_object.shndx = st_shndx;
98 this->is_ordinary_shndx_ = is_ordinary;
99 this->type_ = sym.get_st_type();
100 this->binding_ = sym.get_st_bind();
101 this->override_visibility(sym.get_st_visibility());
102 this->nonvis_ = sym.get_st_nonvis();
103 if (object->is_dynamic())
104 this->in_dyn_ = true;
106 this->in_reg_ = true;
109 // Override the fields in Sized_symbol.
112 template<bool big_endian>
114 Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym,
115 unsigned st_shndx, bool is_ordinary,
116 Object* object, const char* version)
118 this->override_base(sym, st_shndx, is_ordinary, object, version);
119 this->value_ = sym.get_st_value();
120 this->symsize_ = sym.get_st_size();
123 // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version
124 // VERSION. This handles all aliases of TOSYM.
126 template<int size, bool big_endian>
128 Symbol_table::override(Sized_symbol<size>* tosym,
129 const elfcpp::Sym<size, big_endian>& fromsym,
130 unsigned int st_shndx, bool is_ordinary,
131 Object* object, const char* version)
133 tosym->override(fromsym, st_shndx, is_ordinary, object, version);
134 if (tosym->has_alias())
136 Symbol* sym = this->weak_aliases_[tosym];
137 gold_assert(sym != NULL);
138 Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
141 ssym->override(fromsym, st_shndx, is_ordinary, object, version);
142 sym = this->weak_aliases_[ssym];
143 gold_assert(sym != NULL);
144 ssym = this->get_sized_symbol<size>(sym);
146 while (ssym != tosym);
150 // The resolve functions build a little code for each symbol.
151 // Bit 0: 0 for global, 1 for weak.
152 // Bit 1: 0 for regular object, 1 for shared object
153 // Bits 2-3: 0 for normal, 1 for undefined, 2 for common
154 // This gives us values from 0 to 11.
156 static const int global_or_weak_shift = 0;
157 static const unsigned int global_flag = 0 << global_or_weak_shift;
158 static const unsigned int weak_flag = 1 << global_or_weak_shift;
160 static const int regular_or_dynamic_shift = 1;
161 static const unsigned int regular_flag = 0 << regular_or_dynamic_shift;
162 static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift;
164 static const int def_undef_or_common_shift = 2;
165 static const unsigned int def_flag = 0 << def_undef_or_common_shift;
166 static const unsigned int undef_flag = 1 << def_undef_or_common_shift;
167 static const unsigned int common_flag = 2 << def_undef_or_common_shift;
169 // This convenience function combines all the flags based on facts
173 symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
174 unsigned int shndx, bool is_ordinary, elfcpp::STT type)
180 case elfcpp::STB_GLOBAL:
184 case elfcpp::STB_WEAK:
188 case elfcpp::STB_LOCAL:
189 // We should only see externally visible symbols in the symbol
191 gold_error(_("invalid STB_LOCAL symbol in external symbols"));
195 // Any target which wants to handle STB_LOOS, etc., needs to
196 // define a resolve method.
197 gold_error(_("unsupported symbol binding"));
202 bits |= dynamic_flag;
204 bits |= regular_flag;
208 case elfcpp::SHN_UNDEF:
212 case elfcpp::SHN_COMMON:
218 if (type == elfcpp::STT_COMMON)
220 else if (!is_ordinary && Symbol::is_common_shndx(shndx))
230 // Resolve a symbol. This is called the second and subsequent times
231 // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
232 // section index for SYM, possibly adjusted for many sections.
233 // IS_ORDINARY is whether ST_SHNDX is a normal section index rather
234 // than a special code. ORIG_ST_SHNDX is the original section index,
235 // before any munging because of discarded sections, except that all
236 // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
237 // the version of SYM.
239 template<int size, bool big_endian>
241 Symbol_table::resolve(Sized_symbol<size>* to,
242 const elfcpp::Sym<size, big_endian>& sym,
243 unsigned int st_shndx, bool is_ordinary,
244 unsigned int orig_st_shndx,
245 Object* object, const char* version)
247 if (parameters->target().has_resolve())
249 Sized_target<size, big_endian>* sized_target;
250 sized_target = parameters->sized_target<size, big_endian>();
251 sized_target->resolve(to, sym, object, version);
255 if (!object->is_dynamic())
257 // Record that we've seen this symbol in a regular object.
260 else if (st_shndx == elfcpp::SHN_UNDEF
261 && (to->visibility() == elfcpp::STV_HIDDEN
262 || to->visibility() == elfcpp::STV_INTERNAL))
264 // A dynamic object cannot reference a hidden or internal symbol
265 // defined in another object.
266 gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
267 (to->visibility() == elfcpp::STV_HIDDEN
270 to->demangled_name().c_str(),
271 to->object()->name().c_str(),
272 object->name().c_str());
277 // Record that we've seen this symbol in a dynamic object.
281 // Record if we've seen this symbol in a real ELF object (i.e., the
282 // symbol is referenced from outside the world known to the plugin).
283 if (object->pluginobj() == NULL)
284 to->set_in_real_elf();
286 // If we're processing replacement files, allow new symbols to override
287 // the placeholders from the plugin objects.
288 if (to->source() == Symbol::FROM_OBJECT)
290 Pluginobj* obj = to->object()->pluginobj();
292 && parameters->options().plugins()->in_replacement_phase())
294 this->override(to, sym, st_shndx, is_ordinary, object, version);
299 unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
300 object->is_dynamic(),
301 st_shndx, is_ordinary,
304 bool adjust_common_sizes;
305 typename Sized_symbol<size>::Size_type tosize = to->symsize();
306 if (Symbol_table::should_override(to, frombits, object,
307 &adjust_common_sizes))
309 this->override(to, sym, st_shndx, is_ordinary, object, version);
310 if (adjust_common_sizes && tosize > to->symsize())
311 to->set_symsize(tosize);
315 if (adjust_common_sizes && sym.get_st_size() > tosize)
316 to->set_symsize(sym.get_st_size());
317 // The ELF ABI says that even for a reference to a symbol we
318 // merge the visibility.
319 to->override_visibility(sym.get_st_visibility());
322 if (adjust_common_sizes && parameters->options().warn_common())
324 if (tosize > sym.get_st_size())
325 Symbol_table::report_resolve_problem(false,
326 _("common of '%s' overriding "
329 else if (tosize < sym.get_st_size())
330 Symbol_table::report_resolve_problem(false,
331 _("common of '%s' overidden by "
335 Symbol_table::report_resolve_problem(false,
336 _("multiple common of '%s'"),
340 // A new weak undefined reference, merging with an old weak
341 // reference, could be a One Definition Rule (ODR) violation --
342 // especially if the types or sizes of the references differ. We'll
343 // store such pairs and look them up later to make sure they
344 // actually refer to the same lines of code. (Note: not all ODR
345 // violations can be found this way, and not everything this finds
346 // is an ODR violation. But it's helpful to warn about.)
348 if (parameters->options().detect_odr_violations()
349 && sym.get_st_bind() == elfcpp::STB_WEAK
350 && to->binding() == elfcpp::STB_WEAK
351 && orig_st_shndx != elfcpp::SHN_UNDEF
352 && to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF
354 && sym.get_st_size() != 0 // Ignore weird 0-sized symbols.
355 && to->symsize() != 0
356 && (sym.get_st_type() != to->type()
357 || sym.get_st_size() != to->symsize())
358 // C does not have a concept of ODR, so we only need to do this
359 // on C++ symbols. These have (mangled) names starting with _Z.
360 && to->name()[0] == '_' && to->name()[1] == 'Z')
362 Symbol_location fromloc
363 = { object, orig_st_shndx, sym.get_st_value() };
364 Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary),
366 this->candidate_odr_violations_[to->name()].insert(fromloc);
367 this->candidate_odr_violations_[to->name()].insert(toloc);
371 // Handle the core of symbol resolution. This is called with the
372 // existing symbol, TO, and a bitflag describing the new symbol. This
373 // returns true if we should override the existing symbol with the new
374 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
375 // true if we should set the symbol size to the maximum of the TO and
376 // FROM sizes. It handles error conditions.
379 Symbol_table::should_override(const Symbol* to, unsigned int frombits,
380 Object* object, bool* adjust_common_sizes)
382 *adjust_common_sizes = false;
385 if (to->source() == Symbol::IS_UNDEFINED)
386 tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true,
388 else if (to->source() != Symbol::FROM_OBJECT)
389 tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false,
394 unsigned int shndx = to->shndx(&is_ordinary);
395 tobits = symbol_to_bits(to->binding(),
396 to->object()->is_dynamic(),
402 // FIXME: Warn if either but not both of TO and SYM are STT_TLS.
404 // We use a giant switch table for symbol resolution. This code is
405 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
406 // cases; 3) it is easy to change the handling of a particular case.
407 // The alternative would be a series of conditionals, but it is easy
408 // to get the ordering wrong. This could also be done as a table,
409 // but that is no easier to understand than this large switch
412 // These are the values generated by the bit codes.
415 DEF = global_flag | regular_flag | def_flag,
416 WEAK_DEF = weak_flag | regular_flag | def_flag,
417 DYN_DEF = global_flag | dynamic_flag | def_flag,
418 DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag,
419 UNDEF = global_flag | regular_flag | undef_flag,
420 WEAK_UNDEF = weak_flag | regular_flag | undef_flag,
421 DYN_UNDEF = global_flag | dynamic_flag | undef_flag,
422 DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag,
423 COMMON = global_flag | regular_flag | common_flag,
424 WEAK_COMMON = weak_flag | regular_flag | common_flag,
425 DYN_COMMON = global_flag | dynamic_flag | common_flag,
426 DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag
429 switch (tobits * 16 + frombits)
432 // Two definitions of the same symbol.
434 // If either symbol is defined by an object included using
435 // --just-symbols, then don't warn. This is for compatibility
436 // with the GNU linker. FIXME: This is a hack.
437 if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols())
438 || object->just_symbols())
441 Symbol_table::report_resolve_problem(true,
442 _("multiple definition of '%s'"),
446 case WEAK_DEF * 16 + DEF:
447 // We've seen a weak definition, and now we see a strong
448 // definition. In the original SVR4 linker, this was treated as
449 // a multiple definition error. In the Solaris linker and the
450 // GNU linker, a weak definition followed by a regular
451 // definition causes the weak definition to be overridden. We
452 // are currently compatible with the GNU linker. In the future
453 // we should add a target specific option to change this.
457 case DYN_DEF * 16 + DEF:
458 case DYN_WEAK_DEF * 16 + DEF:
459 // We've seen a definition in a dynamic object, and now we see a
460 // definition in a regular object. The definition in the
461 // regular object overrides the definition in the dynamic
465 case UNDEF * 16 + DEF:
466 case WEAK_UNDEF * 16 + DEF:
467 case DYN_UNDEF * 16 + DEF:
468 case DYN_WEAK_UNDEF * 16 + DEF:
469 // We've seen an undefined reference, and now we see a
470 // definition. We use the definition.
473 case COMMON * 16 + DEF:
474 case WEAK_COMMON * 16 + DEF:
475 case DYN_COMMON * 16 + DEF:
476 case DYN_WEAK_COMMON * 16 + DEF:
477 // We've seen a common symbol and now we see a definition. The
478 // definition overrides.
479 if (parameters->options().warn_common())
480 Symbol_table::report_resolve_problem(false,
481 _("definition of '%s' overriding "
486 case DEF * 16 + WEAK_DEF:
487 case WEAK_DEF * 16 + WEAK_DEF:
488 // We've seen a definition and now we see a weak definition. We
489 // ignore the new weak definition.
492 case DYN_DEF * 16 + WEAK_DEF:
493 case DYN_WEAK_DEF * 16 + WEAK_DEF:
494 // We've seen a dynamic definition and now we see a regular weak
495 // definition. The regular weak definition overrides.
498 case UNDEF * 16 + WEAK_DEF:
499 case WEAK_UNDEF * 16 + WEAK_DEF:
500 case DYN_UNDEF * 16 + WEAK_DEF:
501 case DYN_WEAK_UNDEF * 16 + WEAK_DEF:
502 // A weak definition of a currently undefined symbol.
505 case COMMON * 16 + WEAK_DEF:
506 case WEAK_COMMON * 16 + WEAK_DEF:
507 // A weak definition does not override a common definition.
510 case DYN_COMMON * 16 + WEAK_DEF:
511 case DYN_WEAK_COMMON * 16 + WEAK_DEF:
512 // A weak definition does override a definition in a dynamic
514 if (parameters->options().warn_common())
515 Symbol_table::report_resolve_problem(false,
516 _("definition of '%s' overriding "
517 "dynamic common definition"),
521 case DEF * 16 + DYN_DEF:
522 case WEAK_DEF * 16 + DYN_DEF:
523 case DYN_DEF * 16 + DYN_DEF:
524 case DYN_WEAK_DEF * 16 + DYN_DEF:
525 // Ignore a dynamic definition if we already have a definition.
528 case UNDEF * 16 + DYN_DEF:
529 case WEAK_UNDEF * 16 + DYN_DEF:
530 case DYN_UNDEF * 16 + DYN_DEF:
531 case DYN_WEAK_UNDEF * 16 + DYN_DEF:
532 // Use a dynamic definition if we have a reference.
535 case COMMON * 16 + DYN_DEF:
536 case WEAK_COMMON * 16 + DYN_DEF:
537 case DYN_COMMON * 16 + DYN_DEF:
538 case DYN_WEAK_COMMON * 16 + DYN_DEF:
539 // Ignore a dynamic definition if we already have a common
543 case DEF * 16 + DYN_WEAK_DEF:
544 case WEAK_DEF * 16 + DYN_WEAK_DEF:
545 case DYN_DEF * 16 + DYN_WEAK_DEF:
546 case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF:
547 // Ignore a weak dynamic definition if we already have a
551 case UNDEF * 16 + DYN_WEAK_DEF:
552 case WEAK_UNDEF * 16 + DYN_WEAK_DEF:
553 case DYN_UNDEF * 16 + DYN_WEAK_DEF:
554 case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF:
555 // Use a weak dynamic definition if we have a reference.
558 case COMMON * 16 + DYN_WEAK_DEF:
559 case WEAK_COMMON * 16 + DYN_WEAK_DEF:
560 case DYN_COMMON * 16 + DYN_WEAK_DEF:
561 case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF:
562 // Ignore a weak dynamic definition if we already have a common
566 case DEF * 16 + UNDEF:
567 case WEAK_DEF * 16 + UNDEF:
568 case DYN_DEF * 16 + UNDEF:
569 case DYN_WEAK_DEF * 16 + UNDEF:
570 case UNDEF * 16 + UNDEF:
571 // A new undefined reference tells us nothing.
574 case WEAK_UNDEF * 16 + UNDEF:
575 case DYN_UNDEF * 16 + UNDEF:
576 case DYN_WEAK_UNDEF * 16 + UNDEF:
577 // A strong undef overrides a dynamic or weak undef.
580 case COMMON * 16 + UNDEF:
581 case WEAK_COMMON * 16 + UNDEF:
582 case DYN_COMMON * 16 + UNDEF:
583 case DYN_WEAK_COMMON * 16 + UNDEF:
584 // A new undefined reference tells us nothing.
587 case DEF * 16 + WEAK_UNDEF:
588 case WEAK_DEF * 16 + WEAK_UNDEF:
589 case DYN_DEF * 16 + WEAK_UNDEF:
590 case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
591 case UNDEF * 16 + WEAK_UNDEF:
592 case WEAK_UNDEF * 16 + WEAK_UNDEF:
593 case DYN_UNDEF * 16 + WEAK_UNDEF:
594 case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF:
595 case COMMON * 16 + WEAK_UNDEF:
596 case WEAK_COMMON * 16 + WEAK_UNDEF:
597 case DYN_COMMON * 16 + WEAK_UNDEF:
598 case DYN_WEAK_COMMON * 16 + WEAK_UNDEF:
599 // A new weak undefined reference tells us nothing.
602 case DEF * 16 + DYN_UNDEF:
603 case WEAK_DEF * 16 + DYN_UNDEF:
604 case DYN_DEF * 16 + DYN_UNDEF:
605 case DYN_WEAK_DEF * 16 + DYN_UNDEF:
606 case UNDEF * 16 + DYN_UNDEF:
607 case WEAK_UNDEF * 16 + DYN_UNDEF:
608 case DYN_UNDEF * 16 + DYN_UNDEF:
609 case DYN_WEAK_UNDEF * 16 + DYN_UNDEF:
610 case COMMON * 16 + DYN_UNDEF:
611 case WEAK_COMMON * 16 + DYN_UNDEF:
612 case DYN_COMMON * 16 + DYN_UNDEF:
613 case DYN_WEAK_COMMON * 16 + DYN_UNDEF:
614 // A new dynamic undefined reference tells us nothing.
617 case DEF * 16 + DYN_WEAK_UNDEF:
618 case WEAK_DEF * 16 + DYN_WEAK_UNDEF:
619 case DYN_DEF * 16 + DYN_WEAK_UNDEF:
620 case DYN_WEAK_DEF * 16 + DYN_WEAK_UNDEF:
621 case UNDEF * 16 + DYN_WEAK_UNDEF:
622 case WEAK_UNDEF * 16 + DYN_WEAK_UNDEF:
623 case DYN_UNDEF * 16 + DYN_WEAK_UNDEF:
624 case DYN_WEAK_UNDEF * 16 + DYN_WEAK_UNDEF:
625 case COMMON * 16 + DYN_WEAK_UNDEF:
626 case WEAK_COMMON * 16 + DYN_WEAK_UNDEF:
627 case DYN_COMMON * 16 + DYN_WEAK_UNDEF:
628 case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF:
629 // A new weak dynamic undefined reference tells us nothing.
632 case DEF * 16 + COMMON:
633 // A common symbol does not override a definition.
634 if (parameters->options().warn_common())
635 Symbol_table::report_resolve_problem(false,
636 _("common '%s' overridden by "
637 "previous definition"),
641 case WEAK_DEF * 16 + COMMON:
642 case DYN_DEF * 16 + COMMON:
643 case DYN_WEAK_DEF * 16 + COMMON:
644 // A common symbol does override a weak definition or a dynamic
648 case UNDEF * 16 + COMMON:
649 case WEAK_UNDEF * 16 + COMMON:
650 case DYN_UNDEF * 16 + COMMON:
651 case DYN_WEAK_UNDEF * 16 + COMMON:
652 // A common symbol is a definition for a reference.
655 case COMMON * 16 + COMMON:
656 // Set the size to the maximum.
657 *adjust_common_sizes = true;
660 case WEAK_COMMON * 16 + COMMON:
661 // I'm not sure just what a weak common symbol means, but
662 // presumably it can be overridden by a regular common symbol.
665 case DYN_COMMON * 16 + COMMON:
666 case DYN_WEAK_COMMON * 16 + COMMON:
667 // Use the real common symbol, but adjust the size if necessary.
668 *adjust_common_sizes = true;
671 case DEF * 16 + WEAK_COMMON:
672 case WEAK_DEF * 16 + WEAK_COMMON:
673 case DYN_DEF * 16 + WEAK_COMMON:
674 case DYN_WEAK_DEF * 16 + WEAK_COMMON:
675 // Whatever a weak common symbol is, it won't override a
679 case UNDEF * 16 + WEAK_COMMON:
680 case WEAK_UNDEF * 16 + WEAK_COMMON:
681 case DYN_UNDEF * 16 + WEAK_COMMON:
682 case DYN_WEAK_UNDEF * 16 + WEAK_COMMON:
683 // A weak common symbol is better than an undefined symbol.
686 case COMMON * 16 + WEAK_COMMON:
687 case WEAK_COMMON * 16 + WEAK_COMMON:
688 case DYN_COMMON * 16 + WEAK_COMMON:
689 case DYN_WEAK_COMMON * 16 + WEAK_COMMON:
690 // Ignore a weak common symbol in the presence of a real common
694 case DEF * 16 + DYN_COMMON:
695 case WEAK_DEF * 16 + DYN_COMMON:
696 case DYN_DEF * 16 + DYN_COMMON:
697 case DYN_WEAK_DEF * 16 + DYN_COMMON:
698 // Ignore a dynamic common symbol in the presence of a
702 case UNDEF * 16 + DYN_COMMON:
703 case WEAK_UNDEF * 16 + DYN_COMMON:
704 case DYN_UNDEF * 16 + DYN_COMMON:
705 case DYN_WEAK_UNDEF * 16 + DYN_COMMON:
706 // A dynamic common symbol is a definition of sorts.
709 case COMMON * 16 + DYN_COMMON:
710 case WEAK_COMMON * 16 + DYN_COMMON:
711 case DYN_COMMON * 16 + DYN_COMMON:
712 case DYN_WEAK_COMMON * 16 + DYN_COMMON:
713 // Set the size to the maximum.
714 *adjust_common_sizes = true;
717 case DEF * 16 + DYN_WEAK_COMMON:
718 case WEAK_DEF * 16 + DYN_WEAK_COMMON:
719 case DYN_DEF * 16 + DYN_WEAK_COMMON:
720 case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON:
721 // A common symbol is ignored in the face of a definition.
724 case UNDEF * 16 + DYN_WEAK_COMMON:
725 case WEAK_UNDEF * 16 + DYN_WEAK_COMMON:
726 case DYN_UNDEF * 16 + DYN_WEAK_COMMON:
727 case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON:
728 // I guess a weak common symbol is better than a definition.
731 case COMMON * 16 + DYN_WEAK_COMMON:
732 case WEAK_COMMON * 16 + DYN_WEAK_COMMON:
733 case DYN_COMMON * 16 + DYN_WEAK_COMMON:
734 case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON:
735 // Set the size to the maximum.
736 *adjust_common_sizes = true;
744 // Issue an error or warning due to symbol resolution. IS_ERROR
745 // indicates an error rather than a warning. MSG is the error
746 // message; it is expected to have a %s for the symbol name. TO is
747 // the existing symbol. OBJECT is where the new symbol was found.
749 // FIXME: We should have better location information here. When the
750 // symbol is defined, we should be able to pull the location from the
751 // debug info if there is any.
754 Symbol_table::report_resolve_problem(bool is_error, const char* msg,
755 const Symbol* to, Object* object)
757 std::string demangled(to->demangled_name());
758 size_t len = strlen(msg) + demangled.length() + 10;
759 char* buf = new char[len];
760 snprintf(buf, len, msg, demangled.c_str());
764 objname = object->name().c_str();
766 objname = _("command line");
769 gold_error("%s: %s", objname, buf);
771 gold_warning("%s: %s", objname, buf);
775 if (to->source() == Symbol::FROM_OBJECT)
776 objname = to->object()->name().c_str();
778 objname = _("command line");
779 gold_info("%s: %s: previous definition here", program_name, objname);
782 // A special case of should_override which is only called for a strong
783 // defined symbol from a regular object file. This is used when
784 // defining special symbols.
787 Symbol_table::should_override_with_special(const Symbol* to)
789 bool adjust_common_sizes;
790 unsigned int frombits = global_flag | regular_flag | def_flag;
791 bool ret = Symbol_table::should_override(to, frombits, NULL,
792 &adjust_common_sizes);
793 gold_assert(!adjust_common_sizes);
797 // Override symbol base with a special symbol.
800 Symbol::override_base_with_special(const Symbol* from)
802 gold_assert(this->name_ == from->name_ || this->has_alias());
804 this->source_ = from->source_;
805 switch (from->source_)
808 this->u_.from_object = from->u_.from_object;
811 this->u_.in_output_data = from->u_.in_output_data;
813 case IN_OUTPUT_SEGMENT:
814 this->u_.in_output_segment = from->u_.in_output_segment;
824 this->override_version(from->version_);
825 this->type_ = from->type_;
826 this->binding_ = from->binding_;
827 this->override_visibility(from->visibility_);
828 this->nonvis_ = from->nonvis_;
830 // Special symbols are always considered to be regular symbols.
831 this->in_reg_ = true;
833 if (from->needs_dynsym_entry_)
834 this->needs_dynsym_entry_ = true;
835 if (from->needs_dynsym_value_)
836 this->needs_dynsym_value_ = true;
838 // We shouldn't see these flags. If we do, we need to handle them
840 gold_assert(!from->is_target_special_ || this->is_target_special_);
841 gold_assert(!from->is_forwarder_);
842 gold_assert(!from->has_plt_offset_);
843 gold_assert(!from->has_warning_);
844 gold_assert(!from->is_copied_from_dynobj_);
845 gold_assert(!from->is_forced_local_);
848 // Override a symbol with a special symbol.
852 Sized_symbol<size>::override_with_special(const Sized_symbol<size>* from)
854 this->override_base_with_special(from);
855 this->value_ = from->value_;
856 this->symsize_ = from->symsize_;
859 // Override TOSYM with the special symbol FROMSYM. This handles all
864 Symbol_table::override_with_special(Sized_symbol<size>* tosym,
865 const Sized_symbol<size>* fromsym)
867 tosym->override_with_special(fromsym);
868 if (tosym->has_alias())
870 Symbol* sym = this->weak_aliases_[tosym];
871 gold_assert(sym != NULL);
872 Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
875 ssym->override_with_special(fromsym);
876 sym = this->weak_aliases_[ssym];
877 gold_assert(sym != NULL);
878 ssym = this->get_sized_symbol<size>(sym);
880 while (ssym != tosym);
882 if (tosym->binding() == elfcpp::STB_LOCAL
883 || ((tosym->visibility() == elfcpp::STV_HIDDEN
884 || tosym->visibility() == elfcpp::STV_INTERNAL)
885 && (tosym->binding() == elfcpp::STB_GLOBAL
886 || tosym->binding() == elfcpp::STB_WEAK)
887 && !parameters->options().relocatable()))
888 this->force_local(tosym);
891 // Instantiate the templates we need. We could use the configure
892 // script to restrict this to only the ones needed for implemented
895 #ifdef HAVE_TARGET_32_LITTLE
898 Symbol_table::resolve<32, false>(
899 Sized_symbol<32>* to,
900 const elfcpp::Sym<32, false>& sym,
901 unsigned int st_shndx,
903 unsigned int orig_st_shndx,
905 const char* version);
908 #ifdef HAVE_TARGET_32_BIG
911 Symbol_table::resolve<32, true>(
912 Sized_symbol<32>* to,
913 const elfcpp::Sym<32, true>& sym,
914 unsigned int st_shndx,
916 unsigned int orig_st_shndx,
918 const char* version);
921 #ifdef HAVE_TARGET_64_LITTLE
924 Symbol_table::resolve<64, false>(
925 Sized_symbol<64>* to,
926 const elfcpp::Sym<64, false>& sym,
927 unsigned int st_shndx,
929 unsigned int orig_st_shndx,
931 const char* version);
934 #ifdef HAVE_TARGET_64_BIG
937 Symbol_table::resolve<64, true>(
938 Sized_symbol<64>* to,
939 const elfcpp::Sym<64, true>& sym,
940 unsigned int st_shndx,
942 unsigned int orig_st_shndx,
944 const char* version);
947 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
950 Symbol_table::override_with_special<32>(Sized_symbol<32>*,
951 const Sized_symbol<32>*);
954 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
957 Symbol_table::override_with_special<64>(Sized_symbol<64>*,
958 const Sized_symbol<64>*);
961 } // End namespace gold.