1 // resolve.cc -- symbol resolution for gold
3 // Copyright (C) 2006-2015 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
)
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 (!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 // It's possible for a symbol to be defined in an object file
249 // using .symver to give it a version, and for there to also be
250 // a linker script giving that symbol the same version. We
251 // don't want to give a multiple-definition error for this
252 // harmless redefinition.
254 if (to
->source() == Symbol::FROM_OBJECT
255 && to
->object() == object
258 && to
->shndx(&to_is_ordinary
) == st_shndx
260 && to
->value() == sym
.get_st_value())
263 if (parameters
->target().has_resolve())
265 Sized_target
<size
, big_endian
>* sized_target
;
266 sized_target
= parameters
->sized_target
<size
, big_endian
>();
267 sized_target
->resolve(to
, sym
, object
, version
);
271 if (!object
->is_dynamic())
273 if (sym
.get_st_type() == elfcpp::STT_COMMON
274 && (is_ordinary
|| !Symbol::is_common_shndx(st_shndx
)))
276 gold_warning(_("STT_COMMON symbol '%s' in %s "
277 "is not in a common section"),
278 to
->demangled_name().c_str(),
279 to
->object()->name().c_str());
282 // Record that we've seen this symbol in a regular object.
285 else if (st_shndx
== elfcpp::SHN_UNDEF
286 && (to
->visibility() == elfcpp::STV_HIDDEN
287 || to
->visibility() == elfcpp::STV_INTERNAL
))
289 // A dynamic object cannot reference a hidden or internal symbol
290 // defined in another object.
291 gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
292 (to
->visibility() == elfcpp::STV_HIDDEN
295 to
->demangled_name().c_str(),
296 to
->object()->name().c_str(),
297 object
->name().c_str());
302 // Record that we've seen this symbol in a dynamic object.
306 // Record if we've seen this symbol in a real ELF object (i.e., the
307 // symbol is referenced from outside the world known to the plugin).
308 if (object
->pluginobj() == NULL
&& !object
->is_dynamic())
309 to
->set_in_real_elf();
311 // If we're processing replacement files, allow new symbols to override
312 // the placeholders from the plugin objects.
313 // Treat common symbols specially since it is possible that an ELF
314 // file increased the size of the alignment.
315 if (to
->source() == Symbol::FROM_OBJECT
)
317 Pluginobj
* obj
= to
->object()->pluginobj();
319 && parameters
->options().plugins()->in_replacement_phase())
321 bool adjust_common
= false;
322 typename Sized_symbol
<size
>::Size_type tosize
= 0;
323 typename Sized_symbol
<size
>::Value_type tovalue
= 0;
325 && !is_ordinary
&& Symbol::is_common_shndx(st_shndx
))
327 adjust_common
= true;
328 tosize
= to
->symsize();
329 tovalue
= to
->value();
331 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
334 if (tosize
> to
->symsize())
335 to
->set_symsize(tosize
);
336 if (tovalue
> to
->value())
337 to
->set_value(tovalue
);
343 // A new weak undefined reference, merging with an old weak
344 // reference, could be a One Definition Rule (ODR) violation --
345 // especially if the types or sizes of the references differ. We'll
346 // store such pairs and look them up later to make sure they
347 // actually refer to the same lines of code. We also check
348 // combinations of weak and strong, which might occur if one case is
349 // inline and the other is not. (Note: not all ODR violations can
350 // be found this way, and not everything this finds is an ODR
351 // violation. But it's helpful to warn about.)
352 if (parameters
->options().detect_odr_violations()
353 && (sym
.get_st_bind() == elfcpp::STB_WEAK
354 || to
->binding() == elfcpp::STB_WEAK
)
355 && orig_st_shndx
!= elfcpp::SHN_UNDEF
356 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
358 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
359 && to
->symsize() != 0
360 && (sym
.get_st_type() != to
->type()
361 || sym
.get_st_size() != to
->symsize())
362 // C does not have a concept of ODR, so we only need to do this
363 // on C++ symbols. These have (mangled) names starting with _Z.
364 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
366 Symbol_location fromloc
367 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
368 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
369 static_cast<off_t
>(to
->value()) };
370 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
371 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
374 // Plugins don't provide a symbol type, so adopt the existing type
375 // if the FROM symbol is from a plugin.
376 elfcpp::STT fromtype
= (object
->pluginobj() != NULL
378 : sym
.get_st_type());
379 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
380 object
->is_dynamic(),
381 st_shndx
, is_ordinary
);
383 bool adjust_common_sizes
;
385 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
386 if (Symbol_table::should_override(to
, frombits
, fromtype
, OBJECT
,
387 object
, &adjust_common_sizes
,
390 elfcpp::STB tobinding
= to
->binding();
391 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
392 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
393 if (adjust_common_sizes
)
395 if (tosize
> to
->symsize())
396 to
->set_symsize(tosize
);
397 if (tovalue
> to
->value())
398 to
->set_value(tovalue
);
402 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
403 // Remember which kind of UNDEF it was for future reference.
404 to
->set_undef_binding(tobinding
);
409 if (adjust_common_sizes
)
411 if (sym
.get_st_size() > tosize
)
412 to
->set_symsize(sym
.get_st_size());
413 if (sym
.get_st_value() > to
->value())
414 to
->set_value(sym
.get_st_value());
418 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
419 // Remember which kind of UNDEF it was.
420 to
->set_undef_binding(sym
.get_st_bind());
422 // The ELF ABI says that even for a reference to a symbol we
423 // merge the visibility.
424 to
->override_visibility(sym
.get_st_visibility());
427 if (adjust_common_sizes
&& parameters
->options().warn_common())
429 if (tosize
> sym
.get_st_size())
430 Symbol_table::report_resolve_problem(false,
431 _("common of '%s' overriding "
434 else if (tosize
< sym
.get_st_size())
435 Symbol_table::report_resolve_problem(false,
436 _("common of '%s' overidden by "
440 Symbol_table::report_resolve_problem(false,
441 _("multiple common of '%s'"),
446 // Handle the core of symbol resolution. This is called with the
447 // existing symbol, TO, and a bitflag describing the new symbol. This
448 // returns true if we should override the existing symbol with the new
449 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
450 // true if we should set the symbol size to the maximum of the TO and
451 // FROM sizes. It handles error conditions.
454 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
455 elfcpp::STT fromtype
, Defined defined
,
456 Object
* object
, bool* adjust_common_sizes
,
459 *adjust_common_sizes
= false;
460 *adjust_dyndef
= false;
463 if (to
->source() == Symbol::IS_UNDEFINED
)
464 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true);
465 else if (to
->source() != Symbol::FROM_OBJECT
)
466 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false);
470 unsigned int shndx
= to
->shndx(&is_ordinary
);
471 tobits
= symbol_to_bits(to
->binding(),
472 to
->object()->is_dynamic(),
477 if ((to
->type() == elfcpp::STT_TLS
) ^ (fromtype
== elfcpp::STT_TLS
)
478 && !to
->is_placeholder())
479 Symbol_table::report_resolve_problem(true,
480 _("symbol '%s' used as both __thread "
482 to
, defined
, object
);
484 // We use a giant switch table for symbol resolution. This code is
485 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
486 // cases; 3) it is easy to change the handling of a particular case.
487 // The alternative would be a series of conditionals, but it is easy
488 // to get the ordering wrong. This could also be done as a table,
489 // but that is no easier to understand than this large switch
492 // These are the values generated by the bit codes.
495 DEF
= global_flag
| regular_flag
| def_flag
,
496 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
497 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
498 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
499 UNDEF
= global_flag
| regular_flag
| undef_flag
,
500 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
501 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
502 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
503 COMMON
= global_flag
| regular_flag
| common_flag
,
504 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
505 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
506 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
509 switch (tobits
* 16 + frombits
)
512 // Two definitions of the same symbol.
514 // If either symbol is defined by an object included using
515 // --just-symbols, then don't warn. This is for compatibility
516 // with the GNU linker. FIXME: This is a hack.
517 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
518 || (object
!= NULL
&& object
->just_symbols()))
521 if (!parameters
->options().muldefs())
522 Symbol_table::report_resolve_problem(true,
523 _("multiple definition of '%s'"),
524 to
, defined
, object
);
527 case WEAK_DEF
* 16 + DEF
:
528 // We've seen a weak definition, and now we see a strong
529 // definition. In the original SVR4 linker, this was treated as
530 // a multiple definition error. In the Solaris linker and the
531 // GNU linker, a weak definition followed by a regular
532 // definition causes the weak definition to be overridden. We
533 // are currently compatible with the GNU linker. In the future
534 // we should add a target specific option to change this.
538 case DYN_DEF
* 16 + DEF
:
539 case DYN_WEAK_DEF
* 16 + DEF
:
540 // We've seen a definition in a dynamic object, and now we see a
541 // definition in a regular object. The definition in the
542 // regular object overrides the definition in the dynamic
546 case UNDEF
* 16 + DEF
:
547 case WEAK_UNDEF
* 16 + DEF
:
548 case DYN_UNDEF
* 16 + DEF
:
549 case DYN_WEAK_UNDEF
* 16 + DEF
:
550 // We've seen an undefined reference, and now we see a
551 // definition. We use the definition.
554 case COMMON
* 16 + DEF
:
555 case WEAK_COMMON
* 16 + DEF
:
556 case DYN_COMMON
* 16 + DEF
:
557 case DYN_WEAK_COMMON
* 16 + DEF
:
558 // We've seen a common symbol and now we see a definition. The
559 // definition overrides.
560 if (parameters
->options().warn_common())
561 Symbol_table::report_resolve_problem(false,
562 _("definition of '%s' overriding "
564 to
, defined
, object
);
567 case DEF
* 16 + WEAK_DEF
:
568 case WEAK_DEF
* 16 + WEAK_DEF
:
569 // We've seen a definition and now we see a weak definition. We
570 // ignore the new weak definition.
573 case DYN_DEF
* 16 + WEAK_DEF
:
574 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
575 // We've seen a dynamic definition and now we see a regular weak
576 // definition. The regular weak definition overrides.
579 case UNDEF
* 16 + WEAK_DEF
:
580 case WEAK_UNDEF
* 16 + WEAK_DEF
:
581 case DYN_UNDEF
* 16 + WEAK_DEF
:
582 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
583 // A weak definition of a currently undefined symbol.
586 case COMMON
* 16 + WEAK_DEF
:
587 case WEAK_COMMON
* 16 + WEAK_DEF
:
588 // A weak definition does not override a common definition.
591 case DYN_COMMON
* 16 + WEAK_DEF
:
592 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
593 // A weak definition does override a definition in a dynamic
595 if (parameters
->options().warn_common())
596 Symbol_table::report_resolve_problem(false,
597 _("definition of '%s' overriding "
598 "dynamic common definition"),
599 to
, defined
, object
);
602 case DEF
* 16 + DYN_DEF
:
603 case WEAK_DEF
* 16 + DYN_DEF
:
604 case DYN_DEF
* 16 + DYN_DEF
:
605 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
606 // Ignore a dynamic definition if we already have a definition.
609 case UNDEF
* 16 + DYN_DEF
:
610 case DYN_UNDEF
* 16 + DYN_DEF
:
611 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
612 // Use a dynamic definition if we have a reference.
615 case WEAK_UNDEF
* 16 + DYN_DEF
:
616 // When overriding a weak undef by a dynamic definition,
617 // we need to remember that the original undef was weak.
618 *adjust_dyndef
= true;
621 case COMMON
* 16 + DYN_DEF
:
622 case WEAK_COMMON
* 16 + DYN_DEF
:
623 case DYN_COMMON
* 16 + DYN_DEF
:
624 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
625 // Ignore a dynamic definition if we already have a common
629 case DEF
* 16 + DYN_WEAK_DEF
:
630 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
631 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
632 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
633 // Ignore a weak dynamic definition if we already have a
637 case UNDEF
* 16 + DYN_WEAK_DEF
:
638 // When overriding an undef by a dynamic weak definition,
639 // we need to remember that the original undef was not weak.
640 *adjust_dyndef
= true;
643 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
644 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
645 // Use a weak dynamic definition if we have a reference.
648 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
649 // When overriding a weak undef by a dynamic definition,
650 // we need to remember that the original undef was weak.
651 *adjust_dyndef
= true;
654 case COMMON
* 16 + DYN_WEAK_DEF
:
655 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
656 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
657 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
658 // Ignore a weak dynamic definition if we already have a common
662 case DEF
* 16 + UNDEF
:
663 case WEAK_DEF
* 16 + UNDEF
:
664 case UNDEF
* 16 + UNDEF
:
665 // A new undefined reference tells us nothing.
668 case DYN_DEF
* 16 + UNDEF
:
669 case DYN_WEAK_DEF
* 16 + UNDEF
:
670 // For a dynamic def, we need to remember which kind of undef we see.
671 *adjust_dyndef
= true;
674 case WEAK_UNDEF
* 16 + UNDEF
:
675 case DYN_UNDEF
* 16 + UNDEF
:
676 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
677 // A strong undef overrides a dynamic or weak undef.
680 case COMMON
* 16 + UNDEF
:
681 case WEAK_COMMON
* 16 + UNDEF
:
682 case DYN_COMMON
* 16 + UNDEF
:
683 case DYN_WEAK_COMMON
* 16 + UNDEF
:
684 // A new undefined reference tells us nothing.
687 case DEF
* 16 + WEAK_UNDEF
:
688 case WEAK_DEF
* 16 + WEAK_UNDEF
:
689 case UNDEF
* 16 + WEAK_UNDEF
:
690 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
691 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
692 case COMMON
* 16 + WEAK_UNDEF
:
693 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
694 case DYN_COMMON
* 16 + WEAK_UNDEF
:
695 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
696 // A new weak undefined reference tells us nothing unless the
697 // exisiting symbol is a dynamic weak reference.
700 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
701 // A new weak reference overrides an existing dynamic weak reference.
702 // This is necessary because a dynamic weak reference remembers
703 // the old binding, which may not be weak. If we keeps the existing
704 // dynamic weak reference, the weakness may be dropped in the output.
707 case DYN_DEF
* 16 + WEAK_UNDEF
:
708 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
709 // For a dynamic def, we need to remember which kind of undef we see.
710 *adjust_dyndef
= true;
713 case DEF
* 16 + DYN_UNDEF
:
714 case WEAK_DEF
* 16 + DYN_UNDEF
:
715 case DYN_DEF
* 16 + DYN_UNDEF
:
716 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
717 case UNDEF
* 16 + DYN_UNDEF
:
718 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
719 case DYN_UNDEF
* 16 + DYN_UNDEF
:
720 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
721 case COMMON
* 16 + DYN_UNDEF
:
722 case WEAK_COMMON
* 16 + DYN_UNDEF
:
723 case DYN_COMMON
* 16 + DYN_UNDEF
:
724 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
725 // A new dynamic undefined reference tells us nothing.
728 case DEF
* 16 + DYN_WEAK_UNDEF
:
729 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
730 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
731 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
732 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
733 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
734 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
735 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
736 case COMMON
* 16 + DYN_WEAK_UNDEF
:
737 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
738 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
739 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
740 // A new weak dynamic undefined reference tells us nothing.
743 case DEF
* 16 + COMMON
:
744 // A common symbol does not override a definition.
745 if (parameters
->options().warn_common())
746 Symbol_table::report_resolve_problem(false,
747 _("common '%s' overridden by "
748 "previous definition"),
749 to
, defined
, object
);
752 case WEAK_DEF
* 16 + COMMON
:
753 case DYN_DEF
* 16 + COMMON
:
754 case DYN_WEAK_DEF
* 16 + COMMON
:
755 // A common symbol does override a weak definition or a dynamic
759 case UNDEF
* 16 + COMMON
:
760 case WEAK_UNDEF
* 16 + COMMON
:
761 case DYN_UNDEF
* 16 + COMMON
:
762 case DYN_WEAK_UNDEF
* 16 + COMMON
:
763 // A common symbol is a definition for a reference.
766 case COMMON
* 16 + COMMON
:
767 // Set the size to the maximum.
768 *adjust_common_sizes
= true;
771 case WEAK_COMMON
* 16 + COMMON
:
772 // I'm not sure just what a weak common symbol means, but
773 // presumably it can be overridden by a regular common symbol.
776 case DYN_COMMON
* 16 + COMMON
:
777 case DYN_WEAK_COMMON
* 16 + COMMON
:
778 // Use the real common symbol, but adjust the size if necessary.
779 *adjust_common_sizes
= true;
782 case DEF
* 16 + WEAK_COMMON
:
783 case WEAK_DEF
* 16 + WEAK_COMMON
:
784 case DYN_DEF
* 16 + WEAK_COMMON
:
785 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
786 // Whatever a weak common symbol is, it won't override a
790 case UNDEF
* 16 + WEAK_COMMON
:
791 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
792 case DYN_UNDEF
* 16 + WEAK_COMMON
:
793 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
794 // A weak common symbol is better than an undefined symbol.
797 case COMMON
* 16 + WEAK_COMMON
:
798 case WEAK_COMMON
* 16 + WEAK_COMMON
:
799 case DYN_COMMON
* 16 + WEAK_COMMON
:
800 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
801 // Ignore a weak common symbol in the presence of a real common
805 case DEF
* 16 + DYN_COMMON
:
806 case WEAK_DEF
* 16 + DYN_COMMON
:
807 case DYN_DEF
* 16 + DYN_COMMON
:
808 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
809 // Ignore a dynamic common symbol in the presence of a
813 case UNDEF
* 16 + DYN_COMMON
:
814 case WEAK_UNDEF
* 16 + DYN_COMMON
:
815 case DYN_UNDEF
* 16 + DYN_COMMON
:
816 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
817 // A dynamic common symbol is a definition of sorts.
820 case COMMON
* 16 + DYN_COMMON
:
821 case WEAK_COMMON
* 16 + DYN_COMMON
:
822 case DYN_COMMON
* 16 + DYN_COMMON
:
823 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
824 // Set the size to the maximum.
825 *adjust_common_sizes
= true;
828 case DEF
* 16 + DYN_WEAK_COMMON
:
829 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
830 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
831 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
832 // A common symbol is ignored in the face of a definition.
835 case UNDEF
* 16 + DYN_WEAK_COMMON
:
836 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
837 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
838 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
839 // I guess a weak common symbol is better than a definition.
842 case COMMON
* 16 + DYN_WEAK_COMMON
:
843 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
844 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
845 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
846 // Set the size to the maximum.
847 *adjust_common_sizes
= true;
855 // Issue an error or warning due to symbol resolution. IS_ERROR
856 // indicates an error rather than a warning. MSG is the error
857 // message; it is expected to have a %s for the symbol name. TO is
858 // the existing symbol. DEFINED/OBJECT is where the new symbol was
861 // FIXME: We should have better location information here. When the
862 // symbol is defined, we should be able to pull the location from the
863 // debug info if there is any.
866 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
867 const Symbol
* to
, Defined defined
,
870 std::string
demangled(to
->demangled_name());
871 size_t len
= strlen(msg
) + demangled
.length() + 10;
872 char* buf
= new char[len
];
873 snprintf(buf
, len
, msg
, demangled
.c_str());
879 objname
= object
->name().c_str();
882 objname
= _("COPY reloc");
886 objname
= _("command line");
889 objname
= _("linker script");
892 case INCREMENTAL_BASE
:
893 objname
= _("linker defined");
900 gold_error("%s: %s", objname
, buf
);
902 gold_warning("%s: %s", objname
, buf
);
906 if (to
->source() == Symbol::FROM_OBJECT
)
907 objname
= to
->object()->name().c_str();
909 objname
= _("command line");
910 gold_info("%s: %s: previous definition here", program_name
, objname
);
913 // A special case of should_override which is only called for a strong
914 // defined symbol from a regular object file. This is used when
915 // defining special symbols.
918 Symbol_table::should_override_with_special(const Symbol
* to
,
919 elfcpp::STT fromtype
,
922 bool adjust_common_sizes
;
924 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
925 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
926 NULL
, &adjust_common_sizes
,
928 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
932 // Override symbol base with a special symbol.
935 Symbol::override_base_with_special(const Symbol
* from
)
937 bool same_name
= this->name_
== from
->name_
;
938 gold_assert(same_name
|| this->has_alias());
940 // If we are overriding an undef, remember the original binding.
941 if (this->is_undefined())
942 this->set_undef_binding(this->binding_
);
944 this->source_
= from
->source_
;
945 switch (from
->source_
)
948 this->u_
.from_object
= from
->u_
.from_object
;
951 this->u_
.in_output_data
= from
->u_
.in_output_data
;
953 case IN_OUTPUT_SEGMENT
:
954 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
966 // When overriding a versioned symbol with a special symbol, we
967 // may be changing the version. This will happen if we see a
968 // special symbol such as "_end" defined in a shared object with
969 // one version (from a version script), but we want to define it
970 // here with a different version (from a different version
972 this->version_
= from
->version_
;
974 this->type_
= from
->type_
;
975 this->binding_
= from
->binding_
;
976 this->override_visibility(from
->visibility_
);
977 this->nonvis_
= from
->nonvis_
;
979 // Special symbols are always considered to be regular symbols.
980 this->in_reg_
= true;
982 if (from
->needs_dynsym_entry_
)
983 this->needs_dynsym_entry_
= true;
984 if (from
->needs_dynsym_value_
)
985 this->needs_dynsym_value_
= true;
987 this->is_predefined_
= from
->is_predefined_
;
989 // We shouldn't see these flags. If we do, we need to handle them
991 gold_assert(!from
->is_forwarder_
);
992 gold_assert(!from
->has_plt_offset());
993 gold_assert(!from
->has_warning_
);
994 gold_assert(!from
->is_copied_from_dynobj_
);
995 gold_assert(!from
->is_forced_local_
);
998 // Override a symbol with a special symbol.
1002 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
1004 this->override_base_with_special(from
);
1005 this->value_
= from
->value_
;
1006 this->symsize_
= from
->symsize_
;
1009 // Override TOSYM with the special symbol FROMSYM. This handles all
1010 // aliases of TOSYM.
1014 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
1015 const Sized_symbol
<size
>* fromsym
)
1017 tosym
->override_with_special(fromsym
);
1018 if (tosym
->has_alias())
1020 Symbol
* sym
= this->weak_aliases_
[tosym
];
1021 gold_assert(sym
!= NULL
);
1022 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
1025 ssym
->override_with_special(fromsym
);
1026 sym
= this->weak_aliases_
[ssym
];
1027 gold_assert(sym
!= NULL
);
1028 ssym
= this->get_sized_symbol
<size
>(sym
);
1030 while (ssym
!= tosym
);
1032 if (tosym
->binding() == elfcpp::STB_LOCAL
1033 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1034 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1035 && (tosym
->binding() == elfcpp::STB_GLOBAL
1036 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1037 || tosym
->binding() == elfcpp::STB_WEAK
)
1038 && !parameters
->options().relocatable()))
1039 this->force_local(tosym
);
1042 // Instantiate the templates we need. We could use the configure
1043 // script to restrict this to only the ones needed for implemented
1046 // We have to instantiate both big and little endian versions because
1047 // these are used by other templates that depends on size only.
1049 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1052 Symbol_table::resolve
<32, false>(
1053 Sized_symbol
<32>* to
,
1054 const elfcpp::Sym
<32, false>& sym
,
1055 unsigned int st_shndx
,
1057 unsigned int orig_st_shndx
,
1059 const char* version
);
1063 Symbol_table::resolve
<32, true>(
1064 Sized_symbol
<32>* to
,
1065 const elfcpp::Sym
<32, true>& sym
,
1066 unsigned int st_shndx
,
1068 unsigned int orig_st_shndx
,
1070 const char* version
);
1073 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1076 Symbol_table::resolve
<64, false>(
1077 Sized_symbol
<64>* to
,
1078 const elfcpp::Sym
<64, false>& sym
,
1079 unsigned int st_shndx
,
1081 unsigned int orig_st_shndx
,
1083 const char* version
);
1087 Symbol_table::resolve
<64, true>(
1088 Sized_symbol
<64>* to
,
1089 const elfcpp::Sym
<64, true>& sym
,
1090 unsigned int st_shndx
,
1092 unsigned int orig_st_shndx
,
1094 const char* version
);
1097 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1100 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1101 const Sized_symbol
<32>*);
1104 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1107 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1108 const Sized_symbol
<64>*);
1111 } // End namespace gold.