1 // resolve.cc -- symbol resolution for gold
3 // Copyright (C) 2006-2014 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 // Don't override st_type from plugin placeholder symbols.
100 if (object
->pluginobj() == NULL
)
101 this->type_
= sym
.get_st_type();
102 this->binding_
= sym
.get_st_bind();
103 this->override_visibility(sym
.get_st_visibility());
104 this->nonvis_
= sym
.get_st_nonvis();
105 if (object
->is_dynamic())
106 this->in_dyn_
= true;
108 this->in_reg_
= true;
111 // Override the fields in Sized_symbol.
114 template<bool big_endian
>
116 Sized_symbol
<size
>::override(const elfcpp::Sym
<size
, big_endian
>& sym
,
117 unsigned st_shndx
, bool is_ordinary
,
118 Object
* object
, const char* version
)
120 this->override_base(sym
, st_shndx
, is_ordinary
, object
, version
);
121 this->value_
= sym
.get_st_value();
122 this->symsize_
= sym
.get_st_size();
125 // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version
126 // VERSION. This handles all aliases of TOSYM.
128 template<int size
, bool big_endian
>
130 Symbol_table::override(Sized_symbol
<size
>* tosym
,
131 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
132 unsigned int st_shndx
, bool is_ordinary
,
133 Object
* object
, const char* version
)
135 tosym
->override(fromsym
, st_shndx
, is_ordinary
, object
, version
);
136 if (tosym
->has_alias())
138 Symbol
* sym
= this->weak_aliases_
[tosym
];
139 gold_assert(sym
!= NULL
);
140 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
143 ssym
->override(fromsym
, st_shndx
, is_ordinary
, object
, version
);
144 sym
= this->weak_aliases_
[ssym
];
145 gold_assert(sym
!= NULL
);
146 ssym
= this->get_sized_symbol
<size
>(sym
);
148 while (ssym
!= tosym
);
152 // The resolve functions build a little code for each symbol.
153 // Bit 0: 0 for global, 1 for weak.
154 // Bit 1: 0 for regular object, 1 for shared object
155 // Bits 2-3: 0 for normal, 1 for undefined, 2 for common
156 // This gives us values from 0 to 11.
158 static const int global_or_weak_shift
= 0;
159 static const unsigned int global_flag
= 0 << global_or_weak_shift
;
160 static const unsigned int weak_flag
= 1 << global_or_weak_shift
;
162 static const int regular_or_dynamic_shift
= 1;
163 static const unsigned int regular_flag
= 0 << regular_or_dynamic_shift
;
164 static const unsigned int dynamic_flag
= 1 << regular_or_dynamic_shift
;
166 static const int def_undef_or_common_shift
= 2;
167 static const unsigned int def_flag
= 0 << def_undef_or_common_shift
;
168 static const unsigned int undef_flag
= 1 << def_undef_or_common_shift
;
169 static const unsigned int common_flag
= 2 << def_undef_or_common_shift
;
171 // This convenience function combines all the flags based on facts
175 symbol_to_bits(elfcpp::STB binding
, bool is_dynamic
,
176 unsigned int shndx
, bool is_ordinary
, elfcpp::STT type
)
182 case elfcpp::STB_GLOBAL
:
183 case elfcpp::STB_GNU_UNIQUE
:
187 case elfcpp::STB_WEAK
:
191 case elfcpp::STB_LOCAL
:
192 // We should only see externally visible symbols in the symbol
194 gold_error(_("invalid STB_LOCAL symbol in external symbols"));
198 // Any target which wants to handle STB_LOOS, etc., needs to
199 // define a resolve method.
200 gold_error(_("unsupported symbol binding %d"), static_cast<int>(binding
));
205 bits
|= dynamic_flag
;
207 bits
|= regular_flag
;
211 case elfcpp::SHN_UNDEF
:
215 case elfcpp::SHN_COMMON
:
221 if (type
== elfcpp::STT_COMMON
)
223 else if (!is_ordinary
&& Symbol::is_common_shndx(shndx
))
233 // Resolve a symbol. This is called the second and subsequent times
234 // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
235 // section index for SYM, possibly adjusted for many sections.
236 // IS_ORDINARY is whether ST_SHNDX is a normal section index rather
237 // than a special code. ORIG_ST_SHNDX is the original section index,
238 // before any munging because of discarded sections, except that all
239 // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
240 // the version of SYM.
242 template<int size
, bool big_endian
>
244 Symbol_table::resolve(Sized_symbol
<size
>* to
,
245 const elfcpp::Sym
<size
, big_endian
>& sym
,
246 unsigned int st_shndx
, bool is_ordinary
,
247 unsigned int orig_st_shndx
,
248 Object
* object
, const char* version
)
250 // It's possible for a symbol to be defined in an object file
251 // using .symver to give it a version, and for there to also be
252 // a linker script giving that symbol the same version. We
253 // don't want to give a multiple-definition error for this
254 // harmless redefinition.
256 if (to
->source() == Symbol::FROM_OBJECT
257 && to
->object() == object
260 && to
->shndx(&to_is_ordinary
) == st_shndx
262 && to
->value() == sym
.get_st_value())
265 if (parameters
->target().has_resolve())
267 Sized_target
<size
, big_endian
>* sized_target
;
268 sized_target
= parameters
->sized_target
<size
, big_endian
>();
269 sized_target
->resolve(to
, sym
, object
, version
);
273 if (!object
->is_dynamic())
275 // Record that we've seen this symbol in a regular object.
278 else if (st_shndx
== elfcpp::SHN_UNDEF
279 && (to
->visibility() == elfcpp::STV_HIDDEN
280 || to
->visibility() == elfcpp::STV_INTERNAL
))
282 // A dynamic object cannot reference a hidden or internal symbol
283 // defined in another object.
284 gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
285 (to
->visibility() == elfcpp::STV_HIDDEN
288 to
->demangled_name().c_str(),
289 to
->object()->name().c_str(),
290 object
->name().c_str());
295 // Record that we've seen this symbol in a dynamic object.
299 // Record if we've seen this symbol in a real ELF object (i.e., the
300 // symbol is referenced from outside the world known to the plugin).
301 if (object
->pluginobj() == NULL
&& !object
->is_dynamic())
302 to
->set_in_real_elf();
304 // If we're processing replacement files, allow new symbols to override
305 // the placeholders from the plugin objects.
306 // Treat common symbols specially since it is possible that an ELF
307 // file increased the size of the alignment.
308 if (to
->source() == Symbol::FROM_OBJECT
)
310 Pluginobj
* obj
= to
->object()->pluginobj();
312 && parameters
->options().plugins()->in_replacement_phase())
314 bool adjust_common
= false;
315 typename Sized_symbol
<size
>::Size_type tosize
= 0;
316 typename Sized_symbol
<size
>::Value_type tovalue
= 0;
317 if (to
->is_common() && !is_ordinary
&& st_shndx
== elfcpp::SHN_COMMON
)
319 adjust_common
= true;
320 tosize
= to
->symsize();
321 tovalue
= to
->value();
323 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
326 if (tosize
> to
->symsize())
327 to
->set_symsize(tosize
);
328 if (tovalue
> to
->value())
329 to
->set_value(tovalue
);
335 // A new weak undefined reference, merging with an old weak
336 // reference, could be a One Definition Rule (ODR) violation --
337 // especially if the types or sizes of the references differ. We'll
338 // store such pairs and look them up later to make sure they
339 // actually refer to the same lines of code. We also check
340 // combinations of weak and strong, which might occur if one case is
341 // inline and the other is not. (Note: not all ODR violations can
342 // be found this way, and not everything this finds is an ODR
343 // violation. But it's helpful to warn about.)
344 if (parameters
->options().detect_odr_violations()
345 && (sym
.get_st_bind() == elfcpp::STB_WEAK
346 || to
->binding() == elfcpp::STB_WEAK
)
347 && orig_st_shndx
!= elfcpp::SHN_UNDEF
348 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
350 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
351 && to
->symsize() != 0
352 && (sym
.get_st_type() != to
->type()
353 || sym
.get_st_size() != to
->symsize())
354 // C does not have a concept of ODR, so we only need to do this
355 // on C++ symbols. These have (mangled) names starting with _Z.
356 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
358 Symbol_location fromloc
359 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
360 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
361 static_cast<off_t
>(to
->value()) };
362 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
363 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
366 // Plugins don't provide a symbol type, so adopt the existing type
367 // if the FROM symbol is from a plugin.
368 elfcpp::STT fromtype
= (object
->pluginobj() != NULL
370 : sym
.get_st_type());
371 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
372 object
->is_dynamic(),
373 st_shndx
, is_ordinary
,
376 bool adjust_common_sizes
;
378 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
379 if (Symbol_table::should_override(to
, frombits
, fromtype
, OBJECT
,
380 object
, &adjust_common_sizes
,
383 elfcpp::STB tobinding
= to
->binding();
384 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
385 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
386 if (adjust_common_sizes
)
388 if (tosize
> to
->symsize())
389 to
->set_symsize(tosize
);
390 if (tovalue
> to
->value())
391 to
->set_value(tovalue
);
395 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
396 // Remember which kind of UNDEF it was for future reference.
397 to
->set_undef_binding(tobinding
);
402 if (adjust_common_sizes
)
404 if (sym
.get_st_size() > tosize
)
405 to
->set_symsize(sym
.get_st_size());
406 if (sym
.get_st_value() > to
->value())
407 to
->set_value(sym
.get_st_value());
411 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
412 // Remember which kind of UNDEF it was.
413 to
->set_undef_binding(sym
.get_st_bind());
415 // The ELF ABI says that even for a reference to a symbol we
416 // merge the visibility.
417 to
->override_visibility(sym
.get_st_visibility());
420 if (adjust_common_sizes
&& parameters
->options().warn_common())
422 if (tosize
> sym
.get_st_size())
423 Symbol_table::report_resolve_problem(false,
424 _("common of '%s' overriding "
427 else if (tosize
< sym
.get_st_size())
428 Symbol_table::report_resolve_problem(false,
429 _("common of '%s' overidden by "
433 Symbol_table::report_resolve_problem(false,
434 _("multiple common of '%s'"),
439 // Handle the core of symbol resolution. This is called with the
440 // existing symbol, TO, and a bitflag describing the new symbol. This
441 // returns true if we should override the existing symbol with the new
442 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
443 // true if we should set the symbol size to the maximum of the TO and
444 // FROM sizes. It handles error conditions.
447 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
448 elfcpp::STT fromtype
, Defined defined
,
449 Object
* object
, bool* adjust_common_sizes
,
452 *adjust_common_sizes
= false;
453 *adjust_dyndef
= false;
456 if (to
->source() == Symbol::IS_UNDEFINED
)
457 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true,
459 else if (to
->source() != Symbol::FROM_OBJECT
)
460 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false,
465 unsigned int shndx
= to
->shndx(&is_ordinary
);
466 tobits
= symbol_to_bits(to
->binding(),
467 to
->object()->is_dynamic(),
473 if ((to
->type() == elfcpp::STT_TLS
) ^ (fromtype
== elfcpp::STT_TLS
)
474 && !to
->is_placeholder())
475 Symbol_table::report_resolve_problem(true,
476 _("symbol '%s' used as both __thread "
478 to
, defined
, object
);
480 // We use a giant switch table for symbol resolution. This code is
481 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
482 // cases; 3) it is easy to change the handling of a particular case.
483 // The alternative would be a series of conditionals, but it is easy
484 // to get the ordering wrong. This could also be done as a table,
485 // but that is no easier to understand than this large switch
488 // These are the values generated by the bit codes.
491 DEF
= global_flag
| regular_flag
| def_flag
,
492 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
493 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
494 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
495 UNDEF
= global_flag
| regular_flag
| undef_flag
,
496 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
497 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
498 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
499 COMMON
= global_flag
| regular_flag
| common_flag
,
500 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
501 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
502 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
505 switch (tobits
* 16 + frombits
)
508 // Two definitions of the same symbol.
510 // If either symbol is defined by an object included using
511 // --just-symbols, then don't warn. This is for compatibility
512 // with the GNU linker. FIXME: This is a hack.
513 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
514 || (object
!= NULL
&& object
->just_symbols()))
517 if (!parameters
->options().muldefs())
518 Symbol_table::report_resolve_problem(true,
519 _("multiple definition of '%s'"),
520 to
, defined
, object
);
523 case WEAK_DEF
* 16 + DEF
:
524 // We've seen a weak definition, and now we see a strong
525 // definition. In the original SVR4 linker, this was treated as
526 // a multiple definition error. In the Solaris linker and the
527 // GNU linker, a weak definition followed by a regular
528 // definition causes the weak definition to be overridden. We
529 // are currently compatible with the GNU linker. In the future
530 // we should add a target specific option to change this.
534 case DYN_DEF
* 16 + DEF
:
535 case DYN_WEAK_DEF
* 16 + DEF
:
536 // We've seen a definition in a dynamic object, and now we see a
537 // definition in a regular object. The definition in the
538 // regular object overrides the definition in the dynamic
542 case UNDEF
* 16 + DEF
:
543 case WEAK_UNDEF
* 16 + DEF
:
544 case DYN_UNDEF
* 16 + DEF
:
545 case DYN_WEAK_UNDEF
* 16 + DEF
:
546 // We've seen an undefined reference, and now we see a
547 // definition. We use the definition.
550 case COMMON
* 16 + DEF
:
551 case WEAK_COMMON
* 16 + DEF
:
552 case DYN_COMMON
* 16 + DEF
:
553 case DYN_WEAK_COMMON
* 16 + DEF
:
554 // We've seen a common symbol and now we see a definition. The
555 // definition overrides.
556 if (parameters
->options().warn_common())
557 Symbol_table::report_resolve_problem(false,
558 _("definition of '%s' overriding "
560 to
, defined
, object
);
563 case DEF
* 16 + WEAK_DEF
:
564 case WEAK_DEF
* 16 + WEAK_DEF
:
565 // We've seen a definition and now we see a weak definition. We
566 // ignore the new weak definition.
569 case DYN_DEF
* 16 + WEAK_DEF
:
570 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
571 // We've seen a dynamic definition and now we see a regular weak
572 // definition. The regular weak definition overrides.
575 case UNDEF
* 16 + WEAK_DEF
:
576 case WEAK_UNDEF
* 16 + WEAK_DEF
:
577 case DYN_UNDEF
* 16 + WEAK_DEF
:
578 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
579 // A weak definition of a currently undefined symbol.
582 case COMMON
* 16 + WEAK_DEF
:
583 case WEAK_COMMON
* 16 + WEAK_DEF
:
584 // A weak definition does not override a common definition.
587 case DYN_COMMON
* 16 + WEAK_DEF
:
588 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
589 // A weak definition does override a definition in a dynamic
591 if (parameters
->options().warn_common())
592 Symbol_table::report_resolve_problem(false,
593 _("definition of '%s' overriding "
594 "dynamic common definition"),
595 to
, defined
, object
);
598 case DEF
* 16 + DYN_DEF
:
599 case WEAK_DEF
* 16 + DYN_DEF
:
600 case DYN_DEF
* 16 + DYN_DEF
:
601 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
602 // Ignore a dynamic definition if we already have a definition.
605 case UNDEF
* 16 + DYN_DEF
:
606 case DYN_UNDEF
* 16 + DYN_DEF
:
607 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
608 // Use a dynamic definition if we have a reference.
611 case WEAK_UNDEF
* 16 + DYN_DEF
:
612 // When overriding a weak undef by a dynamic definition,
613 // we need to remember that the original undef was weak.
614 *adjust_dyndef
= true;
617 case COMMON
* 16 + DYN_DEF
:
618 case WEAK_COMMON
* 16 + DYN_DEF
:
619 case DYN_COMMON
* 16 + DYN_DEF
:
620 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
621 // Ignore a dynamic definition if we already have a common
625 case DEF
* 16 + DYN_WEAK_DEF
:
626 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
627 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
628 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
629 // Ignore a weak dynamic definition if we already have a
633 case UNDEF
* 16 + DYN_WEAK_DEF
:
634 // When overriding an undef by a dynamic weak definition,
635 // we need to remember that the original undef was not weak.
636 *adjust_dyndef
= true;
639 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
640 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
641 // Use a weak dynamic definition if we have a reference.
644 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
645 // When overriding a weak undef by a dynamic definition,
646 // we need to remember that the original undef was weak.
647 *adjust_dyndef
= true;
650 case COMMON
* 16 + DYN_WEAK_DEF
:
651 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
652 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
653 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
654 // Ignore a weak dynamic definition if we already have a common
658 case DEF
* 16 + UNDEF
:
659 case WEAK_DEF
* 16 + UNDEF
:
660 case UNDEF
* 16 + UNDEF
:
661 // A new undefined reference tells us nothing.
664 case DYN_DEF
* 16 + UNDEF
:
665 case DYN_WEAK_DEF
* 16 + UNDEF
:
666 // For a dynamic def, we need to remember which kind of undef we see.
667 *adjust_dyndef
= true;
670 case WEAK_UNDEF
* 16 + UNDEF
:
671 case DYN_UNDEF
* 16 + UNDEF
:
672 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
673 // A strong undef overrides a dynamic or weak undef.
676 case COMMON
* 16 + UNDEF
:
677 case WEAK_COMMON
* 16 + UNDEF
:
678 case DYN_COMMON
* 16 + UNDEF
:
679 case DYN_WEAK_COMMON
* 16 + UNDEF
:
680 // A new undefined reference tells us nothing.
683 case DEF
* 16 + WEAK_UNDEF
:
684 case WEAK_DEF
* 16 + WEAK_UNDEF
:
685 case UNDEF
* 16 + WEAK_UNDEF
:
686 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
687 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
688 case COMMON
* 16 + WEAK_UNDEF
:
689 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
690 case DYN_COMMON
* 16 + WEAK_UNDEF
:
691 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
692 // A new weak undefined reference tells us nothing unless the
693 // exisiting symbol is a dynamic weak reference.
696 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
697 // A new weak reference overrides an existing dynamic weak reference.
698 // This is necessary because a dynamic weak reference remembers
699 // the old binding, which may not be weak. If we keeps the existing
700 // dynamic weak reference, the weakness may be dropped in the output.
703 case DYN_DEF
* 16 + WEAK_UNDEF
:
704 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
705 // For a dynamic def, we need to remember which kind of undef we see.
706 *adjust_dyndef
= true;
709 case DEF
* 16 + DYN_UNDEF
:
710 case WEAK_DEF
* 16 + DYN_UNDEF
:
711 case DYN_DEF
* 16 + DYN_UNDEF
:
712 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
713 case UNDEF
* 16 + DYN_UNDEF
:
714 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
715 case DYN_UNDEF
* 16 + DYN_UNDEF
:
716 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
717 case COMMON
* 16 + DYN_UNDEF
:
718 case WEAK_COMMON
* 16 + DYN_UNDEF
:
719 case DYN_COMMON
* 16 + DYN_UNDEF
:
720 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
721 // A new dynamic undefined reference tells us nothing.
724 case DEF
* 16 + DYN_WEAK_UNDEF
:
725 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
726 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
727 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
728 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
729 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
730 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
731 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
732 case COMMON
* 16 + DYN_WEAK_UNDEF
:
733 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
734 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
735 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
736 // A new weak dynamic undefined reference tells us nothing.
739 case DEF
* 16 + COMMON
:
740 // A common symbol does not override a definition.
741 if (parameters
->options().warn_common())
742 Symbol_table::report_resolve_problem(false,
743 _("common '%s' overridden by "
744 "previous definition"),
745 to
, defined
, object
);
748 case WEAK_DEF
* 16 + COMMON
:
749 case DYN_DEF
* 16 + COMMON
:
750 case DYN_WEAK_DEF
* 16 + COMMON
:
751 // A common symbol does override a weak definition or a dynamic
755 case UNDEF
* 16 + COMMON
:
756 case WEAK_UNDEF
* 16 + COMMON
:
757 case DYN_UNDEF
* 16 + COMMON
:
758 case DYN_WEAK_UNDEF
* 16 + COMMON
:
759 // A common symbol is a definition for a reference.
762 case COMMON
* 16 + COMMON
:
763 // Set the size to the maximum.
764 *adjust_common_sizes
= true;
767 case WEAK_COMMON
* 16 + COMMON
:
768 // I'm not sure just what a weak common symbol means, but
769 // presumably it can be overridden by a regular common symbol.
772 case DYN_COMMON
* 16 + COMMON
:
773 case DYN_WEAK_COMMON
* 16 + COMMON
:
774 // Use the real common symbol, but adjust the size if necessary.
775 *adjust_common_sizes
= true;
778 case DEF
* 16 + WEAK_COMMON
:
779 case WEAK_DEF
* 16 + WEAK_COMMON
:
780 case DYN_DEF
* 16 + WEAK_COMMON
:
781 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
782 // Whatever a weak common symbol is, it won't override a
786 case UNDEF
* 16 + WEAK_COMMON
:
787 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
788 case DYN_UNDEF
* 16 + WEAK_COMMON
:
789 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
790 // A weak common symbol is better than an undefined symbol.
793 case COMMON
* 16 + WEAK_COMMON
:
794 case WEAK_COMMON
* 16 + WEAK_COMMON
:
795 case DYN_COMMON
* 16 + WEAK_COMMON
:
796 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
797 // Ignore a weak common symbol in the presence of a real common
801 case DEF
* 16 + DYN_COMMON
:
802 case WEAK_DEF
* 16 + DYN_COMMON
:
803 case DYN_DEF
* 16 + DYN_COMMON
:
804 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
805 // Ignore a dynamic common symbol in the presence of a
809 case UNDEF
* 16 + DYN_COMMON
:
810 case WEAK_UNDEF
* 16 + DYN_COMMON
:
811 case DYN_UNDEF
* 16 + DYN_COMMON
:
812 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
813 // A dynamic common symbol is a definition of sorts.
816 case COMMON
* 16 + DYN_COMMON
:
817 case WEAK_COMMON
* 16 + DYN_COMMON
:
818 case DYN_COMMON
* 16 + DYN_COMMON
:
819 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
820 // Set the size to the maximum.
821 *adjust_common_sizes
= true;
824 case DEF
* 16 + DYN_WEAK_COMMON
:
825 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
826 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
827 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
828 // A common symbol is ignored in the face of a definition.
831 case UNDEF
* 16 + DYN_WEAK_COMMON
:
832 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
833 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
834 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
835 // I guess a weak common symbol is better than a definition.
838 case COMMON
* 16 + DYN_WEAK_COMMON
:
839 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
840 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
841 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
842 // Set the size to the maximum.
843 *adjust_common_sizes
= true;
851 // Issue an error or warning due to symbol resolution. IS_ERROR
852 // indicates an error rather than a warning. MSG is the error
853 // message; it is expected to have a %s for the symbol name. TO is
854 // the existing symbol. DEFINED/OBJECT is where the new symbol was
857 // FIXME: We should have better location information here. When the
858 // symbol is defined, we should be able to pull the location from the
859 // debug info if there is any.
862 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
863 const Symbol
* to
, Defined defined
,
866 std::string
demangled(to
->demangled_name());
867 size_t len
= strlen(msg
) + demangled
.length() + 10;
868 char* buf
= new char[len
];
869 snprintf(buf
, len
, msg
, demangled
.c_str());
875 objname
= object
->name().c_str();
878 objname
= _("COPY reloc");
882 objname
= _("command line");
885 objname
= _("linker script");
888 case INCREMENTAL_BASE
:
889 objname
= _("linker defined");
896 gold_error("%s: %s", objname
, buf
);
898 gold_warning("%s: %s", objname
, buf
);
902 if (to
->source() == Symbol::FROM_OBJECT
)
903 objname
= to
->object()->name().c_str();
905 objname
= _("command line");
906 gold_info("%s: %s: previous definition here", program_name
, objname
);
909 // A special case of should_override which is only called for a strong
910 // defined symbol from a regular object file. This is used when
911 // defining special symbols.
914 Symbol_table::should_override_with_special(const Symbol
* to
,
915 elfcpp::STT fromtype
,
918 bool adjust_common_sizes
;
920 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
921 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
922 NULL
, &adjust_common_sizes
,
924 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
928 // Override symbol base with a special symbol.
931 Symbol::override_base_with_special(const Symbol
* from
)
933 bool same_name
= this->name_
== from
->name_
;
934 gold_assert(same_name
|| this->has_alias());
936 // If we are overriding an undef, remember the original binding.
937 if (this->is_undefined())
938 this->set_undef_binding(this->binding_
);
940 this->source_
= from
->source_
;
941 switch (from
->source_
)
944 this->u_
.from_object
= from
->u_
.from_object
;
947 this->u_
.in_output_data
= from
->u_
.in_output_data
;
949 case IN_OUTPUT_SEGMENT
:
950 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
962 // When overriding a versioned symbol with a special symbol, we
963 // may be changing the version. This will happen if we see a
964 // special symbol such as "_end" defined in a shared object with
965 // one version (from a version script), but we want to define it
966 // here with a different version (from a different version
968 this->version_
= from
->version_
;
970 this->type_
= from
->type_
;
971 this->binding_
= from
->binding_
;
972 this->override_visibility(from
->visibility_
);
973 this->nonvis_
= from
->nonvis_
;
975 // Special symbols are always considered to be regular symbols.
976 this->in_reg_
= true;
978 if (from
->needs_dynsym_entry_
)
979 this->needs_dynsym_entry_
= true;
980 if (from
->needs_dynsym_value_
)
981 this->needs_dynsym_value_
= true;
983 this->is_predefined_
= from
->is_predefined_
;
985 // We shouldn't see these flags. If we do, we need to handle them
987 gold_assert(!from
->is_forwarder_
);
988 gold_assert(!from
->has_plt_offset());
989 gold_assert(!from
->has_warning_
);
990 gold_assert(!from
->is_copied_from_dynobj_
);
991 gold_assert(!from
->is_forced_local_
);
994 // Override a symbol with a special symbol.
998 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
1000 this->override_base_with_special(from
);
1001 this->value_
= from
->value_
;
1002 this->symsize_
= from
->symsize_
;
1005 // Override TOSYM with the special symbol FROMSYM. This handles all
1006 // aliases of TOSYM.
1010 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
1011 const Sized_symbol
<size
>* fromsym
)
1013 tosym
->override_with_special(fromsym
);
1014 if (tosym
->has_alias())
1016 Symbol
* sym
= this->weak_aliases_
[tosym
];
1017 gold_assert(sym
!= NULL
);
1018 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
1021 ssym
->override_with_special(fromsym
);
1022 sym
= this->weak_aliases_
[ssym
];
1023 gold_assert(sym
!= NULL
);
1024 ssym
= this->get_sized_symbol
<size
>(sym
);
1026 while (ssym
!= tosym
);
1028 if (tosym
->binding() == elfcpp::STB_LOCAL
1029 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1030 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1031 && (tosym
->binding() == elfcpp::STB_GLOBAL
1032 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1033 || tosym
->binding() == elfcpp::STB_WEAK
)
1034 && !parameters
->options().relocatable()))
1035 this->force_local(tosym
);
1038 // Instantiate the templates we need. We could use the configure
1039 // script to restrict this to only the ones needed for implemented
1042 // We have to instantiate both big and little endian versions because
1043 // these are used by other templates that depends on size only.
1045 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1048 Symbol_table::resolve
<32, false>(
1049 Sized_symbol
<32>* to
,
1050 const elfcpp::Sym
<32, false>& sym
,
1051 unsigned int st_shndx
,
1053 unsigned int orig_st_shndx
,
1055 const char* version
);
1059 Symbol_table::resolve
<32, true>(
1060 Sized_symbol
<32>* to
,
1061 const elfcpp::Sym
<32, true>& sym
,
1062 unsigned int st_shndx
,
1064 unsigned int orig_st_shndx
,
1066 const char* version
);
1069 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1072 Symbol_table::resolve
<64, false>(
1073 Sized_symbol
<64>* to
,
1074 const elfcpp::Sym
<64, false>& sym
,
1075 unsigned int st_shndx
,
1077 unsigned int orig_st_shndx
,
1079 const char* version
);
1083 Symbol_table::resolve
<64, true>(
1084 Sized_symbol
<64>* to
,
1085 const elfcpp::Sym
<64, true>& sym
,
1086 unsigned int st_shndx
,
1088 unsigned int orig_st_shndx
,
1090 const char* version
);
1093 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1096 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1097 const Sized_symbol
<32>*);
1100 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1103 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1104 const Sized_symbol
<64>*);
1107 } // End namespace gold.