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
:
181 case elfcpp::STB_GNU_UNIQUE
:
185 case elfcpp::STB_WEAK
:
189 case elfcpp::STB_LOCAL
:
190 // We should only see externally visible symbols in the symbol
192 gold_error(_("invalid STB_LOCAL symbol in external symbols"));
196 // Any target which wants to handle STB_LOOS, etc., needs to
197 // define a resolve method.
198 gold_error(_("unsupported symbol binding"));
203 bits
|= dynamic_flag
;
205 bits
|= regular_flag
;
209 case elfcpp::SHN_UNDEF
:
213 case elfcpp::SHN_COMMON
:
219 if (type
== elfcpp::STT_COMMON
)
221 else if (!is_ordinary
&& Symbol::is_common_shndx(shndx
))
231 // Resolve a symbol. This is called the second and subsequent times
232 // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
233 // section index for SYM, possibly adjusted for many sections.
234 // IS_ORDINARY is whether ST_SHNDX is a normal section index rather
235 // than a special code. ORIG_ST_SHNDX is the original section index,
236 // before any munging because of discarded sections, except that all
237 // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
238 // the version of SYM.
240 template<int size
, bool big_endian
>
242 Symbol_table::resolve(Sized_symbol
<size
>* to
,
243 const elfcpp::Sym
<size
, big_endian
>& sym
,
244 unsigned int st_shndx
, bool is_ordinary
,
245 unsigned int orig_st_shndx
,
246 Object
* object
, const char* version
)
248 if (parameters
->target().has_resolve())
250 Sized_target
<size
, big_endian
>* sized_target
;
251 sized_target
= parameters
->sized_target
<size
, big_endian
>();
252 sized_target
->resolve(to
, sym
, object
, version
);
256 if (!object
->is_dynamic())
258 // Record that we've seen this symbol in a regular object.
261 else if (st_shndx
== elfcpp::SHN_UNDEF
262 && (to
->visibility() == elfcpp::STV_HIDDEN
263 || to
->visibility() == elfcpp::STV_INTERNAL
))
265 // A dynamic object cannot reference a hidden or internal symbol
266 // defined in another object.
267 gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
268 (to
->visibility() == elfcpp::STV_HIDDEN
271 to
->demangled_name().c_str(),
272 to
->object()->name().c_str(),
273 object
->name().c_str());
278 // Record that we've seen this symbol in a dynamic object.
282 // Record if we've seen this symbol in a real ELF object (i.e., the
283 // symbol is referenced from outside the world known to the plugin).
284 if (object
->pluginobj() == NULL
)
285 to
->set_in_real_elf();
287 // If we're processing replacement files, allow new symbols to override
288 // the placeholders from the plugin objects.
289 if (to
->source() == Symbol::FROM_OBJECT
)
291 Pluginobj
* obj
= to
->object()->pluginobj();
293 && parameters
->options().plugins()->in_replacement_phase())
295 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
300 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
301 object
->is_dynamic(),
302 st_shndx
, is_ordinary
,
305 bool adjust_common_sizes
;
306 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
307 if (Symbol_table::should_override(to
, frombits
, object
,
308 &adjust_common_sizes
))
310 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
311 if (adjust_common_sizes
&& tosize
> to
->symsize())
312 to
->set_symsize(tosize
);
316 if (adjust_common_sizes
&& sym
.get_st_size() > tosize
)
317 to
->set_symsize(sym
.get_st_size());
318 // The ELF ABI says that even for a reference to a symbol we
319 // merge the visibility.
320 to
->override_visibility(sym
.get_st_visibility());
323 if (adjust_common_sizes
&& parameters
->options().warn_common())
325 if (tosize
> sym
.get_st_size())
326 Symbol_table::report_resolve_problem(false,
327 _("common of '%s' overriding "
330 else if (tosize
< sym
.get_st_size())
331 Symbol_table::report_resolve_problem(false,
332 _("common of '%s' overidden by "
336 Symbol_table::report_resolve_problem(false,
337 _("multiple common of '%s'"),
341 // A new weak undefined reference, merging with an old weak
342 // reference, could be a One Definition Rule (ODR) violation --
343 // especially if the types or sizes of the references differ. We'll
344 // store such pairs and look them up later to make sure they
345 // actually refer to the same lines of code. (Note: not all ODR
346 // violations can be found this way, and not everything this finds
347 // is an ODR violation. But it's helpful to warn about.)
349 if (parameters
->options().detect_odr_violations()
350 && sym
.get_st_bind() == elfcpp::STB_WEAK
351 && to
->binding() == elfcpp::STB_WEAK
352 && orig_st_shndx
!= elfcpp::SHN_UNDEF
353 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
355 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
356 && to
->symsize() != 0
357 && (sym
.get_st_type() != to
->type()
358 || sym
.get_st_size() != to
->symsize())
359 // C does not have a concept of ODR, so we only need to do this
360 // on C++ symbols. These have (mangled) names starting with _Z.
361 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
363 Symbol_location fromloc
364 = { object
, orig_st_shndx
, sym
.get_st_value() };
365 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
367 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
368 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
372 // Handle the core of symbol resolution. This is called with the
373 // existing symbol, TO, and a bitflag describing the new symbol. This
374 // returns true if we should override the existing symbol with the new
375 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
376 // true if we should set the symbol size to the maximum of the TO and
377 // FROM sizes. It handles error conditions.
380 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
381 Object
* object
, bool* adjust_common_sizes
)
383 *adjust_common_sizes
= false;
386 if (to
->source() == Symbol::IS_UNDEFINED
)
387 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true,
389 else if (to
->source() != Symbol::FROM_OBJECT
)
390 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false,
395 unsigned int shndx
= to
->shndx(&is_ordinary
);
396 tobits
= symbol_to_bits(to
->binding(),
397 to
->object()->is_dynamic(),
403 // FIXME: Warn if either but not both of TO and SYM are STT_TLS.
405 // We use a giant switch table for symbol resolution. This code is
406 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
407 // cases; 3) it is easy to change the handling of a particular case.
408 // The alternative would be a series of conditionals, but it is easy
409 // to get the ordering wrong. This could also be done as a table,
410 // but that is no easier to understand than this large switch
413 // These are the values generated by the bit codes.
416 DEF
= global_flag
| regular_flag
| def_flag
,
417 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
418 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
419 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
420 UNDEF
= global_flag
| regular_flag
| undef_flag
,
421 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
422 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
423 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
424 COMMON
= global_flag
| regular_flag
| common_flag
,
425 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
426 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
427 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
430 switch (tobits
* 16 + frombits
)
433 // Two definitions of the same symbol.
435 // If either symbol is defined by an object included using
436 // --just-symbols, then don't warn. This is for compatibility
437 // with the GNU linker. FIXME: This is a hack.
438 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
439 || object
->just_symbols())
442 Symbol_table::report_resolve_problem(true,
443 _("multiple definition of '%s'"),
447 case WEAK_DEF
* 16 + DEF
:
448 // We've seen a weak definition, and now we see a strong
449 // definition. In the original SVR4 linker, this was treated as
450 // a multiple definition error. In the Solaris linker and the
451 // GNU linker, a weak definition followed by a regular
452 // definition causes the weak definition to be overridden. We
453 // are currently compatible with the GNU linker. In the future
454 // we should add a target specific option to change this.
458 case DYN_DEF
* 16 + DEF
:
459 case DYN_WEAK_DEF
* 16 + DEF
:
460 // We've seen a definition in a dynamic object, and now we see a
461 // definition in a regular object. The definition in the
462 // regular object overrides the definition in the dynamic
466 case UNDEF
* 16 + DEF
:
467 case WEAK_UNDEF
* 16 + DEF
:
468 case DYN_UNDEF
* 16 + DEF
:
469 case DYN_WEAK_UNDEF
* 16 + DEF
:
470 // We've seen an undefined reference, and now we see a
471 // definition. We use the definition.
474 case COMMON
* 16 + DEF
:
475 case WEAK_COMMON
* 16 + DEF
:
476 case DYN_COMMON
* 16 + DEF
:
477 case DYN_WEAK_COMMON
* 16 + DEF
:
478 // We've seen a common symbol and now we see a definition. The
479 // definition overrides.
480 if (parameters
->options().warn_common())
481 Symbol_table::report_resolve_problem(false,
482 _("definition of '%s' overriding "
487 case DEF
* 16 + WEAK_DEF
:
488 case WEAK_DEF
* 16 + WEAK_DEF
:
489 // We've seen a definition and now we see a weak definition. We
490 // ignore the new weak definition.
493 case DYN_DEF
* 16 + WEAK_DEF
:
494 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
495 // We've seen a dynamic definition and now we see a regular weak
496 // definition. The regular weak definition overrides.
499 case UNDEF
* 16 + WEAK_DEF
:
500 case WEAK_UNDEF
* 16 + WEAK_DEF
:
501 case DYN_UNDEF
* 16 + WEAK_DEF
:
502 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
503 // A weak definition of a currently undefined symbol.
506 case COMMON
* 16 + WEAK_DEF
:
507 case WEAK_COMMON
* 16 + WEAK_DEF
:
508 // A weak definition does not override a common definition.
511 case DYN_COMMON
* 16 + WEAK_DEF
:
512 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
513 // A weak definition does override a definition in a dynamic
515 if (parameters
->options().warn_common())
516 Symbol_table::report_resolve_problem(false,
517 _("definition of '%s' overriding "
518 "dynamic common definition"),
522 case DEF
* 16 + DYN_DEF
:
523 case WEAK_DEF
* 16 + DYN_DEF
:
524 case DYN_DEF
* 16 + DYN_DEF
:
525 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
526 // Ignore a dynamic definition if we already have a definition.
529 case UNDEF
* 16 + DYN_DEF
:
530 case WEAK_UNDEF
* 16 + DYN_DEF
:
531 case DYN_UNDEF
* 16 + DYN_DEF
:
532 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
533 // Use a dynamic definition if we have a reference.
536 case COMMON
* 16 + DYN_DEF
:
537 case WEAK_COMMON
* 16 + DYN_DEF
:
538 case DYN_COMMON
* 16 + DYN_DEF
:
539 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
540 // Ignore a dynamic definition if we already have a common
544 case DEF
* 16 + DYN_WEAK_DEF
:
545 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
546 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
547 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
548 // Ignore a weak dynamic definition if we already have a
552 case UNDEF
* 16 + DYN_WEAK_DEF
:
553 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
554 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
555 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
556 // Use a weak dynamic definition if we have a reference.
559 case COMMON
* 16 + DYN_WEAK_DEF
:
560 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
561 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
562 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
563 // Ignore a weak dynamic definition if we already have a common
567 case DEF
* 16 + UNDEF
:
568 case WEAK_DEF
* 16 + UNDEF
:
569 case DYN_DEF
* 16 + UNDEF
:
570 case DYN_WEAK_DEF
* 16 + UNDEF
:
571 case UNDEF
* 16 + UNDEF
:
572 // A new undefined reference tells us nothing.
575 case WEAK_UNDEF
* 16 + UNDEF
:
576 case DYN_UNDEF
* 16 + UNDEF
:
577 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
578 // A strong undef overrides a dynamic or weak undef.
581 case COMMON
* 16 + UNDEF
:
582 case WEAK_COMMON
* 16 + UNDEF
:
583 case DYN_COMMON
* 16 + UNDEF
:
584 case DYN_WEAK_COMMON
* 16 + UNDEF
:
585 // A new undefined reference tells us nothing.
588 case DEF
* 16 + WEAK_UNDEF
:
589 case WEAK_DEF
* 16 + WEAK_UNDEF
:
590 case DYN_DEF
* 16 + WEAK_UNDEF
:
591 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
592 case UNDEF
* 16 + WEAK_UNDEF
:
593 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
594 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
595 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
596 case COMMON
* 16 + WEAK_UNDEF
:
597 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
598 case DYN_COMMON
* 16 + WEAK_UNDEF
:
599 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
600 // A new weak undefined reference tells us nothing.
603 case DEF
* 16 + DYN_UNDEF
:
604 case WEAK_DEF
* 16 + DYN_UNDEF
:
605 case DYN_DEF
* 16 + DYN_UNDEF
:
606 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
607 case UNDEF
* 16 + DYN_UNDEF
:
608 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
609 case DYN_UNDEF
* 16 + DYN_UNDEF
:
610 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
611 case COMMON
* 16 + DYN_UNDEF
:
612 case WEAK_COMMON
* 16 + DYN_UNDEF
:
613 case DYN_COMMON
* 16 + DYN_UNDEF
:
614 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
615 // A new dynamic undefined reference tells us nothing.
618 case DEF
* 16 + DYN_WEAK_UNDEF
:
619 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
620 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
621 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
622 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
623 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
624 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
625 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
626 case COMMON
* 16 + DYN_WEAK_UNDEF
:
627 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
628 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
629 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
630 // A new weak dynamic undefined reference tells us nothing.
633 case DEF
* 16 + COMMON
:
634 // A common symbol does not override a definition.
635 if (parameters
->options().warn_common())
636 Symbol_table::report_resolve_problem(false,
637 _("common '%s' overridden by "
638 "previous definition"),
642 case WEAK_DEF
* 16 + COMMON
:
643 case DYN_DEF
* 16 + COMMON
:
644 case DYN_WEAK_DEF
* 16 + COMMON
:
645 // A common symbol does override a weak definition or a dynamic
649 case UNDEF
* 16 + COMMON
:
650 case WEAK_UNDEF
* 16 + COMMON
:
651 case DYN_UNDEF
* 16 + COMMON
:
652 case DYN_WEAK_UNDEF
* 16 + COMMON
:
653 // A common symbol is a definition for a reference.
656 case COMMON
* 16 + COMMON
:
657 // Set the size to the maximum.
658 *adjust_common_sizes
= true;
661 case WEAK_COMMON
* 16 + COMMON
:
662 // I'm not sure just what a weak common symbol means, but
663 // presumably it can be overridden by a regular common symbol.
666 case DYN_COMMON
* 16 + COMMON
:
667 case DYN_WEAK_COMMON
* 16 + COMMON
:
668 // Use the real common symbol, but adjust the size if necessary.
669 *adjust_common_sizes
= true;
672 case DEF
* 16 + WEAK_COMMON
:
673 case WEAK_DEF
* 16 + WEAK_COMMON
:
674 case DYN_DEF
* 16 + WEAK_COMMON
:
675 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
676 // Whatever a weak common symbol is, it won't override a
680 case UNDEF
* 16 + WEAK_COMMON
:
681 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
682 case DYN_UNDEF
* 16 + WEAK_COMMON
:
683 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
684 // A weak common symbol is better than an undefined symbol.
687 case COMMON
* 16 + WEAK_COMMON
:
688 case WEAK_COMMON
* 16 + WEAK_COMMON
:
689 case DYN_COMMON
* 16 + WEAK_COMMON
:
690 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
691 // Ignore a weak common symbol in the presence of a real common
695 case DEF
* 16 + DYN_COMMON
:
696 case WEAK_DEF
* 16 + DYN_COMMON
:
697 case DYN_DEF
* 16 + DYN_COMMON
:
698 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
699 // Ignore a dynamic common symbol in the presence of a
703 case UNDEF
* 16 + DYN_COMMON
:
704 case WEAK_UNDEF
* 16 + DYN_COMMON
:
705 case DYN_UNDEF
* 16 + DYN_COMMON
:
706 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
707 // A dynamic common symbol is a definition of sorts.
710 case COMMON
* 16 + DYN_COMMON
:
711 case WEAK_COMMON
* 16 + DYN_COMMON
:
712 case DYN_COMMON
* 16 + DYN_COMMON
:
713 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
714 // Set the size to the maximum.
715 *adjust_common_sizes
= true;
718 case DEF
* 16 + DYN_WEAK_COMMON
:
719 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
720 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
721 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
722 // A common symbol is ignored in the face of a definition.
725 case UNDEF
* 16 + DYN_WEAK_COMMON
:
726 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
727 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
728 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
729 // I guess a weak common symbol is better than a definition.
732 case COMMON
* 16 + DYN_WEAK_COMMON
:
733 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
734 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
735 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
736 // Set the size to the maximum.
737 *adjust_common_sizes
= true;
745 // Issue an error or warning due to symbol resolution. IS_ERROR
746 // indicates an error rather than a warning. MSG is the error
747 // message; it is expected to have a %s for the symbol name. TO is
748 // the existing symbol. OBJECT is where the new symbol was found.
750 // FIXME: We should have better location information here. When the
751 // symbol is defined, we should be able to pull the location from the
752 // debug info if there is any.
755 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
756 const Symbol
* to
, Object
* object
)
758 std::string
demangled(to
->demangled_name());
759 size_t len
= strlen(msg
) + demangled
.length() + 10;
760 char* buf
= new char[len
];
761 snprintf(buf
, len
, msg
, demangled
.c_str());
765 objname
= object
->name().c_str();
767 objname
= _("command line");
770 gold_error("%s: %s", objname
, buf
);
772 gold_warning("%s: %s", objname
, buf
);
776 if (to
->source() == Symbol::FROM_OBJECT
)
777 objname
= to
->object()->name().c_str();
779 objname
= _("command line");
780 gold_info("%s: %s: previous definition here", program_name
, objname
);
783 // A special case of should_override which is only called for a strong
784 // defined symbol from a regular object file. This is used when
785 // defining special symbols.
788 Symbol_table::should_override_with_special(const Symbol
* to
)
790 bool adjust_common_sizes
;
791 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
792 bool ret
= Symbol_table::should_override(to
, frombits
, NULL
,
793 &adjust_common_sizes
);
794 gold_assert(!adjust_common_sizes
);
798 // Override symbol base with a special symbol.
801 Symbol::override_base_with_special(const Symbol
* from
)
803 gold_assert(this->name_
== from
->name_
|| this->has_alias());
805 this->source_
= from
->source_
;
806 switch (from
->source_
)
809 this->u_
.from_object
= from
->u_
.from_object
;
812 this->u_
.in_output_data
= from
->u_
.in_output_data
;
814 case IN_OUTPUT_SEGMENT
:
815 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
825 this->override_version(from
->version_
);
826 this->type_
= from
->type_
;
827 this->binding_
= from
->binding_
;
828 this->override_visibility(from
->visibility_
);
829 this->nonvis_
= from
->nonvis_
;
831 // Special symbols are always considered to be regular symbols.
832 this->in_reg_
= true;
834 if (from
->needs_dynsym_entry_
)
835 this->needs_dynsym_entry_
= true;
836 if (from
->needs_dynsym_value_
)
837 this->needs_dynsym_value_
= true;
839 // We shouldn't see these flags. If we do, we need to handle them
841 gold_assert(!from
->is_target_special_
|| this->is_target_special_
);
842 gold_assert(!from
->is_forwarder_
);
843 gold_assert(!from
->has_plt_offset_
);
844 gold_assert(!from
->has_warning_
);
845 gold_assert(!from
->is_copied_from_dynobj_
);
846 gold_assert(!from
->is_forced_local_
);
849 // Override a symbol with a special symbol.
853 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
855 this->override_base_with_special(from
);
856 this->value_
= from
->value_
;
857 this->symsize_
= from
->symsize_
;
860 // Override TOSYM with the special symbol FROMSYM. This handles all
865 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
866 const Sized_symbol
<size
>* fromsym
)
868 tosym
->override_with_special(fromsym
);
869 if (tosym
->has_alias())
871 Symbol
* sym
= this->weak_aliases_
[tosym
];
872 gold_assert(sym
!= NULL
);
873 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
876 ssym
->override_with_special(fromsym
);
877 sym
= this->weak_aliases_
[ssym
];
878 gold_assert(sym
!= NULL
);
879 ssym
= this->get_sized_symbol
<size
>(sym
);
881 while (ssym
!= tosym
);
883 if (tosym
->binding() == elfcpp::STB_LOCAL
884 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
885 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
886 && (tosym
->binding() == elfcpp::STB_GLOBAL
887 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
888 || tosym
->binding() == elfcpp::STB_WEAK
)
889 && !parameters
->options().relocatable()))
890 this->force_local(tosym
);
893 // Instantiate the templates we need. We could use the configure
894 // script to restrict this to only the ones needed for implemented
897 #ifdef HAVE_TARGET_32_LITTLE
900 Symbol_table::resolve
<32, false>(
901 Sized_symbol
<32>* to
,
902 const elfcpp::Sym
<32, false>& sym
,
903 unsigned int st_shndx
,
905 unsigned int orig_st_shndx
,
907 const char* version
);
910 #ifdef HAVE_TARGET_32_BIG
913 Symbol_table::resolve
<32, true>(
914 Sized_symbol
<32>* to
,
915 const elfcpp::Sym
<32, true>& sym
,
916 unsigned int st_shndx
,
918 unsigned int orig_st_shndx
,
920 const char* version
);
923 #ifdef HAVE_TARGET_64_LITTLE
926 Symbol_table::resolve
<64, false>(
927 Sized_symbol
<64>* to
,
928 const elfcpp::Sym
<64, false>& sym
,
929 unsigned int st_shndx
,
931 unsigned int orig_st_shndx
,
933 const char* version
);
936 #ifdef HAVE_TARGET_64_BIG
939 Symbol_table::resolve
<64, true>(
940 Sized_symbol
<64>* to
,
941 const elfcpp::Sym
<64, true>& sym
,
942 unsigned int st_shndx
,
944 unsigned int orig_st_shndx
,
946 const char* version
);
949 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
952 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
953 const Sized_symbol
<32>*);
956 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
959 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
960 const Sized_symbol
<64>*);
963 } // End namespace gold.