1 // resolve.cc -- symbol resolution for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 %d"), static_cast<int>(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 // 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 // Record that we've seen this symbol in a regular object.
276 else if (st_shndx
== elfcpp::SHN_UNDEF
277 && (to
->visibility() == elfcpp::STV_HIDDEN
278 || to
->visibility() == elfcpp::STV_INTERNAL
))
280 // A dynamic object cannot reference a hidden or internal symbol
281 // defined in another object.
282 gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
283 (to
->visibility() == elfcpp::STV_HIDDEN
286 to
->demangled_name().c_str(),
287 to
->object()->name().c_str(),
288 object
->name().c_str());
293 // Record that we've seen this symbol in a dynamic object.
297 // Record if we've seen this symbol in a real ELF object (i.e., the
298 // symbol is referenced from outside the world known to the plugin).
299 if (object
->pluginobj() == NULL
&& !object
->is_dynamic())
300 to
->set_in_real_elf();
302 // If we're processing replacement files, allow new symbols to override
303 // the placeholders from the plugin objects.
304 if (to
->source() == Symbol::FROM_OBJECT
)
306 Pluginobj
* obj
= to
->object()->pluginobj();
308 && parameters
->options().plugins()->in_replacement_phase())
310 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
315 // A new weak undefined reference, merging with an old weak
316 // reference, could be a One Definition Rule (ODR) violation --
317 // especially if the types or sizes of the references differ. We'll
318 // store such pairs and look them up later to make sure they
319 // actually refer to the same lines of code. We also check
320 // combinations of weak and strong, which might occur if one case is
321 // inline and the other is not. (Note: not all ODR violations can
322 // be found this way, and not everything this finds is an ODR
323 // violation. But it's helpful to warn about.)
324 if (parameters
->options().detect_odr_violations()
325 && (sym
.get_st_bind() == elfcpp::STB_WEAK
326 || to
->binding() == elfcpp::STB_WEAK
)
327 && orig_st_shndx
!= elfcpp::SHN_UNDEF
328 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
330 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
331 && to
->symsize() != 0
332 && (sym
.get_st_type() != to
->type()
333 || sym
.get_st_size() != to
->symsize())
334 // C does not have a concept of ODR, so we only need to do this
335 // on C++ symbols. These have (mangled) names starting with _Z.
336 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
338 Symbol_location fromloc
339 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
340 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
341 static_cast<off_t
>(to
->value()) };
342 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
343 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
346 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
347 object
->is_dynamic(),
348 st_shndx
, is_ordinary
,
351 bool adjust_common_sizes
;
353 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
354 if (Symbol_table::should_override(to
, frombits
, sym
.get_st_type(), OBJECT
,
355 object
, &adjust_common_sizes
,
358 elfcpp::STB tobinding
= to
->binding();
359 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
360 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
361 if (adjust_common_sizes
)
363 if (tosize
> to
->symsize())
364 to
->set_symsize(tosize
);
365 if (tovalue
> to
->value())
366 to
->set_value(tovalue
);
370 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
371 // Remember which kind of UNDEF it was for future reference.
372 to
->set_undef_binding(tobinding
);
377 if (adjust_common_sizes
)
379 if (sym
.get_st_size() > tosize
)
380 to
->set_symsize(sym
.get_st_size());
381 if (sym
.get_st_value() > to
->value())
382 to
->set_value(sym
.get_st_value());
386 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
387 // Remember which kind of UNDEF it was.
388 to
->set_undef_binding(sym
.get_st_bind());
390 // The ELF ABI says that even for a reference to a symbol we
391 // merge the visibility.
392 to
->override_visibility(sym
.get_st_visibility());
395 if (adjust_common_sizes
&& parameters
->options().warn_common())
397 if (tosize
> sym
.get_st_size())
398 Symbol_table::report_resolve_problem(false,
399 _("common of '%s' overriding "
402 else if (tosize
< sym
.get_st_size())
403 Symbol_table::report_resolve_problem(false,
404 _("common of '%s' overidden by "
408 Symbol_table::report_resolve_problem(false,
409 _("multiple common of '%s'"),
414 // Handle the core of symbol resolution. This is called with the
415 // existing symbol, TO, and a bitflag describing the new symbol. This
416 // returns true if we should override the existing symbol with the new
417 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
418 // true if we should set the symbol size to the maximum of the TO and
419 // FROM sizes. It handles error conditions.
422 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
423 elfcpp::STT fromtype
, Defined defined
,
424 Object
* object
, bool* adjust_common_sizes
,
427 *adjust_common_sizes
= false;
428 *adjust_dyndef
= false;
431 if (to
->source() == Symbol::IS_UNDEFINED
)
432 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true,
434 else if (to
->source() != Symbol::FROM_OBJECT
)
435 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false,
440 unsigned int shndx
= to
->shndx(&is_ordinary
);
441 tobits
= symbol_to_bits(to
->binding(),
442 to
->object()->is_dynamic(),
448 if (to
->type() == elfcpp::STT_TLS
449 ? fromtype
!= elfcpp::STT_TLS
450 : fromtype
== elfcpp::STT_TLS
)
451 Symbol_table::report_resolve_problem(true,
452 _("symbol '%s' used as both __thread "
454 to
, defined
, object
);
456 // We use a giant switch table for symbol resolution. This code is
457 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
458 // cases; 3) it is easy to change the handling of a particular case.
459 // The alternative would be a series of conditionals, but it is easy
460 // to get the ordering wrong. This could also be done as a table,
461 // but that is no easier to understand than this large switch
464 // These are the values generated by the bit codes.
467 DEF
= global_flag
| regular_flag
| def_flag
,
468 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
469 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
470 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
471 UNDEF
= global_flag
| regular_flag
| undef_flag
,
472 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
473 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
474 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
475 COMMON
= global_flag
| regular_flag
| common_flag
,
476 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
477 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
478 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
481 switch (tobits
* 16 + frombits
)
484 // Two definitions of the same symbol.
486 // If either symbol is defined by an object included using
487 // --just-symbols, then don't warn. This is for compatibility
488 // with the GNU linker. FIXME: This is a hack.
489 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
490 || (object
!= NULL
&& object
->just_symbols()))
493 if (!parameters
->options().muldefs())
494 Symbol_table::report_resolve_problem(true,
495 _("multiple definition of '%s'"),
496 to
, defined
, object
);
499 case WEAK_DEF
* 16 + DEF
:
500 // We've seen a weak definition, and now we see a strong
501 // definition. In the original SVR4 linker, this was treated as
502 // a multiple definition error. In the Solaris linker and the
503 // GNU linker, a weak definition followed by a regular
504 // definition causes the weak definition to be overridden. We
505 // are currently compatible with the GNU linker. In the future
506 // we should add a target specific option to change this.
510 case DYN_DEF
* 16 + DEF
:
511 case DYN_WEAK_DEF
* 16 + DEF
:
512 // We've seen a definition in a dynamic object, and now we see a
513 // definition in a regular object. The definition in the
514 // regular object overrides the definition in the dynamic
518 case UNDEF
* 16 + DEF
:
519 case WEAK_UNDEF
* 16 + DEF
:
520 case DYN_UNDEF
* 16 + DEF
:
521 case DYN_WEAK_UNDEF
* 16 + DEF
:
522 // We've seen an undefined reference, and now we see a
523 // definition. We use the definition.
526 case COMMON
* 16 + DEF
:
527 case WEAK_COMMON
* 16 + DEF
:
528 case DYN_COMMON
* 16 + DEF
:
529 case DYN_WEAK_COMMON
* 16 + DEF
:
530 // We've seen a common symbol and now we see a definition. The
531 // definition overrides.
532 if (parameters
->options().warn_common())
533 Symbol_table::report_resolve_problem(false,
534 _("definition of '%s' overriding "
536 to
, defined
, object
);
539 case DEF
* 16 + WEAK_DEF
:
540 case WEAK_DEF
* 16 + WEAK_DEF
:
541 // We've seen a definition and now we see a weak definition. We
542 // ignore the new weak definition.
545 case DYN_DEF
* 16 + WEAK_DEF
:
546 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
547 // We've seen a dynamic definition and now we see a regular weak
548 // definition. The regular weak definition overrides.
551 case UNDEF
* 16 + WEAK_DEF
:
552 case WEAK_UNDEF
* 16 + WEAK_DEF
:
553 case DYN_UNDEF
* 16 + WEAK_DEF
:
554 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
555 // A weak definition of a currently undefined symbol.
558 case COMMON
* 16 + WEAK_DEF
:
559 case WEAK_COMMON
* 16 + WEAK_DEF
:
560 // A weak definition does not override a common definition.
563 case DYN_COMMON
* 16 + WEAK_DEF
:
564 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
565 // A weak definition does override a definition in a dynamic
567 if (parameters
->options().warn_common())
568 Symbol_table::report_resolve_problem(false,
569 _("definition of '%s' overriding "
570 "dynamic common definition"),
571 to
, defined
, object
);
574 case DEF
* 16 + DYN_DEF
:
575 case WEAK_DEF
* 16 + DYN_DEF
:
576 case DYN_DEF
* 16 + DYN_DEF
:
577 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
578 // Ignore a dynamic definition if we already have a definition.
581 case UNDEF
* 16 + DYN_DEF
:
582 case DYN_UNDEF
* 16 + DYN_DEF
:
583 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
584 // Use a dynamic definition if we have a reference.
587 case WEAK_UNDEF
* 16 + DYN_DEF
:
588 // When overriding a weak undef by a dynamic definition,
589 // we need to remember that the original undef was weak.
590 *adjust_dyndef
= true;
593 case COMMON
* 16 + DYN_DEF
:
594 case WEAK_COMMON
* 16 + DYN_DEF
:
595 case DYN_COMMON
* 16 + DYN_DEF
:
596 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
597 // Ignore a dynamic definition if we already have a common
601 case DEF
* 16 + DYN_WEAK_DEF
:
602 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
603 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
604 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
605 // Ignore a weak dynamic definition if we already have a
609 case UNDEF
* 16 + DYN_WEAK_DEF
:
610 // When overriding an undef by a dynamic weak definition,
611 // we need to remember that the original undef was not weak.
612 *adjust_dyndef
= true;
615 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
616 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
617 // Use a weak dynamic definition if we have a reference.
620 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
621 // When overriding a weak undef by a dynamic definition,
622 // we need to remember that the original undef was weak.
623 *adjust_dyndef
= true;
626 case COMMON
* 16 + DYN_WEAK_DEF
:
627 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
628 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
629 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
630 // Ignore a weak dynamic definition if we already have a common
634 case DEF
* 16 + UNDEF
:
635 case WEAK_DEF
* 16 + UNDEF
:
636 case UNDEF
* 16 + UNDEF
:
637 // A new undefined reference tells us nothing.
640 case DYN_DEF
* 16 + UNDEF
:
641 case DYN_WEAK_DEF
* 16 + UNDEF
:
642 // For a dynamic def, we need to remember which kind of undef we see.
643 *adjust_dyndef
= true;
646 case WEAK_UNDEF
* 16 + UNDEF
:
647 case DYN_UNDEF
* 16 + UNDEF
:
648 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
649 // A strong undef overrides a dynamic or weak undef.
652 case COMMON
* 16 + UNDEF
:
653 case WEAK_COMMON
* 16 + UNDEF
:
654 case DYN_COMMON
* 16 + UNDEF
:
655 case DYN_WEAK_COMMON
* 16 + UNDEF
:
656 // A new undefined reference tells us nothing.
659 case DEF
* 16 + WEAK_UNDEF
:
660 case WEAK_DEF
* 16 + WEAK_UNDEF
:
661 case UNDEF
* 16 + WEAK_UNDEF
:
662 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
663 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
664 case COMMON
* 16 + WEAK_UNDEF
:
665 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
666 case DYN_COMMON
* 16 + WEAK_UNDEF
:
667 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
668 // A new weak undefined reference tells us nothing unless the
669 // exisiting symbol is a dynamic weak reference.
672 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
673 // A new weak reference overrides an existing dynamic weak reference.
674 // This is necessary because a dynamic weak reference remembers
675 // the old binding, which may not be weak. If we keeps the existing
676 // dynamic weak reference, the weakness may be dropped in the output.
679 case DYN_DEF
* 16 + WEAK_UNDEF
:
680 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
681 // For a dynamic def, we need to remember which kind of undef we see.
682 *adjust_dyndef
= true;
685 case DEF
* 16 + DYN_UNDEF
:
686 case WEAK_DEF
* 16 + DYN_UNDEF
:
687 case DYN_DEF
* 16 + DYN_UNDEF
:
688 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
689 case UNDEF
* 16 + DYN_UNDEF
:
690 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
691 case DYN_UNDEF
* 16 + DYN_UNDEF
:
692 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
693 case COMMON
* 16 + DYN_UNDEF
:
694 case WEAK_COMMON
* 16 + DYN_UNDEF
:
695 case DYN_COMMON
* 16 + DYN_UNDEF
:
696 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
697 // A new dynamic undefined reference tells us nothing.
700 case DEF
* 16 + DYN_WEAK_UNDEF
:
701 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
702 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
703 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
704 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
705 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
706 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
707 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
708 case COMMON
* 16 + DYN_WEAK_UNDEF
:
709 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
710 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
711 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
712 // A new weak dynamic undefined reference tells us nothing.
715 case DEF
* 16 + COMMON
:
716 // A common symbol does not override a definition.
717 if (parameters
->options().warn_common())
718 Symbol_table::report_resolve_problem(false,
719 _("common '%s' overridden by "
720 "previous definition"),
721 to
, defined
, object
);
724 case WEAK_DEF
* 16 + COMMON
:
725 case DYN_DEF
* 16 + COMMON
:
726 case DYN_WEAK_DEF
* 16 + COMMON
:
727 // A common symbol does override a weak definition or a dynamic
731 case UNDEF
* 16 + COMMON
:
732 case WEAK_UNDEF
* 16 + COMMON
:
733 case DYN_UNDEF
* 16 + COMMON
:
734 case DYN_WEAK_UNDEF
* 16 + COMMON
:
735 // A common symbol is a definition for a reference.
738 case COMMON
* 16 + COMMON
:
739 // Set the size to the maximum.
740 *adjust_common_sizes
= true;
743 case WEAK_COMMON
* 16 + COMMON
:
744 // I'm not sure just what a weak common symbol means, but
745 // presumably it can be overridden by a regular common symbol.
748 case DYN_COMMON
* 16 + COMMON
:
749 case DYN_WEAK_COMMON
* 16 + COMMON
:
750 // Use the real common symbol, but adjust the size if necessary.
751 *adjust_common_sizes
= true;
754 case DEF
* 16 + WEAK_COMMON
:
755 case WEAK_DEF
* 16 + WEAK_COMMON
:
756 case DYN_DEF
* 16 + WEAK_COMMON
:
757 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
758 // Whatever a weak common symbol is, it won't override a
762 case UNDEF
* 16 + WEAK_COMMON
:
763 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
764 case DYN_UNDEF
* 16 + WEAK_COMMON
:
765 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
766 // A weak common symbol is better than an undefined symbol.
769 case COMMON
* 16 + WEAK_COMMON
:
770 case WEAK_COMMON
* 16 + WEAK_COMMON
:
771 case DYN_COMMON
* 16 + WEAK_COMMON
:
772 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
773 // Ignore a weak common symbol in the presence of a real common
777 case DEF
* 16 + DYN_COMMON
:
778 case WEAK_DEF
* 16 + DYN_COMMON
:
779 case DYN_DEF
* 16 + DYN_COMMON
:
780 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
781 // Ignore a dynamic common symbol in the presence of a
785 case UNDEF
* 16 + DYN_COMMON
:
786 case WEAK_UNDEF
* 16 + DYN_COMMON
:
787 case DYN_UNDEF
* 16 + DYN_COMMON
:
788 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
789 // A dynamic common symbol is a definition of sorts.
792 case COMMON
* 16 + DYN_COMMON
:
793 case WEAK_COMMON
* 16 + DYN_COMMON
:
794 case DYN_COMMON
* 16 + DYN_COMMON
:
795 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
796 // Set the size to the maximum.
797 *adjust_common_sizes
= true;
800 case DEF
* 16 + DYN_WEAK_COMMON
:
801 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
802 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
803 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
804 // A common symbol is ignored in the face of a definition.
807 case UNDEF
* 16 + DYN_WEAK_COMMON
:
808 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
809 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
810 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
811 // I guess a weak common symbol is better than a definition.
814 case COMMON
* 16 + DYN_WEAK_COMMON
:
815 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
816 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
817 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
818 // Set the size to the maximum.
819 *adjust_common_sizes
= true;
827 // Issue an error or warning due to symbol resolution. IS_ERROR
828 // indicates an error rather than a warning. MSG is the error
829 // message; it is expected to have a %s for the symbol name. TO is
830 // the existing symbol. DEFINED/OBJECT is where the new symbol was
833 // FIXME: We should have better location information here. When the
834 // symbol is defined, we should be able to pull the location from the
835 // debug info if there is any.
838 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
839 const Symbol
* to
, Defined defined
,
842 std::string
demangled(to
->demangled_name());
843 size_t len
= strlen(msg
) + demangled
.length() + 10;
844 char* buf
= new char[len
];
845 snprintf(buf
, len
, msg
, demangled
.c_str());
851 objname
= object
->name().c_str();
854 objname
= _("COPY reloc");
858 objname
= _("command line");
861 objname
= _("linker script");
864 case INCREMENTAL_BASE
:
865 objname
= _("linker defined");
872 gold_error("%s: %s", objname
, buf
);
874 gold_warning("%s: %s", objname
, buf
);
878 if (to
->source() == Symbol::FROM_OBJECT
)
879 objname
= to
->object()->name().c_str();
881 objname
= _("command line");
882 gold_info("%s: %s: previous definition here", program_name
, objname
);
885 // A special case of should_override which is only called for a strong
886 // defined symbol from a regular object file. This is used when
887 // defining special symbols.
890 Symbol_table::should_override_with_special(const Symbol
* to
,
891 elfcpp::STT fromtype
,
894 bool adjust_common_sizes
;
896 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
897 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
898 NULL
, &adjust_common_sizes
,
900 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
904 // Override symbol base with a special symbol.
907 Symbol::override_base_with_special(const Symbol
* from
)
909 bool same_name
= this->name_
== from
->name_
;
910 gold_assert(same_name
|| this->has_alias());
912 this->source_
= from
->source_
;
913 switch (from
->source_
)
916 this->u_
.from_object
= from
->u_
.from_object
;
919 this->u_
.in_output_data
= from
->u_
.in_output_data
;
921 case IN_OUTPUT_SEGMENT
:
922 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
934 // When overriding a versioned symbol with a special symbol, we
935 // may be changing the version. This will happen if we see a
936 // special symbol such as "_end" defined in a shared object with
937 // one version (from a version script), but we want to define it
938 // here with a different version (from a different version
940 this->version_
= from
->version_
;
942 this->type_
= from
->type_
;
943 this->binding_
= from
->binding_
;
944 this->override_visibility(from
->visibility_
);
945 this->nonvis_
= from
->nonvis_
;
947 // Special symbols are always considered to be regular symbols.
948 this->in_reg_
= true;
950 if (from
->needs_dynsym_entry_
)
951 this->needs_dynsym_entry_
= true;
952 if (from
->needs_dynsym_value_
)
953 this->needs_dynsym_value_
= true;
955 this->is_predefined_
= from
->is_predefined_
;
957 // We shouldn't see these flags. If we do, we need to handle them
959 gold_assert(!from
->is_forwarder_
);
960 gold_assert(!from
->has_plt_offset());
961 gold_assert(!from
->has_warning_
);
962 gold_assert(!from
->is_copied_from_dynobj_
);
963 gold_assert(!from
->is_forced_local_
);
966 // Override a symbol with a special symbol.
970 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
972 this->override_base_with_special(from
);
973 this->value_
= from
->value_
;
974 this->symsize_
= from
->symsize_
;
977 // Override TOSYM with the special symbol FROMSYM. This handles all
982 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
983 const Sized_symbol
<size
>* fromsym
)
985 tosym
->override_with_special(fromsym
);
986 if (tosym
->has_alias())
988 Symbol
* sym
= this->weak_aliases_
[tosym
];
989 gold_assert(sym
!= NULL
);
990 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
993 ssym
->override_with_special(fromsym
);
994 sym
= this->weak_aliases_
[ssym
];
995 gold_assert(sym
!= NULL
);
996 ssym
= this->get_sized_symbol
<size
>(sym
);
998 while (ssym
!= tosym
);
1000 if (tosym
->binding() == elfcpp::STB_LOCAL
1001 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1002 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1003 && (tosym
->binding() == elfcpp::STB_GLOBAL
1004 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1005 || tosym
->binding() == elfcpp::STB_WEAK
)
1006 && !parameters
->options().relocatable()))
1007 this->force_local(tosym
);
1010 // Instantiate the templates we need. We could use the configure
1011 // script to restrict this to only the ones needed for implemented
1014 // We have to instantiate both big and little endian versions because
1015 // these are used by other templates that depends on size only.
1017 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1020 Symbol_table::resolve
<32, false>(
1021 Sized_symbol
<32>* to
,
1022 const elfcpp::Sym
<32, false>& sym
,
1023 unsigned int st_shndx
,
1025 unsigned int orig_st_shndx
,
1027 const char* version
);
1031 Symbol_table::resolve
<32, true>(
1032 Sized_symbol
<32>* to
,
1033 const elfcpp::Sym
<32, true>& sym
,
1034 unsigned int st_shndx
,
1036 unsigned int orig_st_shndx
,
1038 const char* version
);
1041 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1044 Symbol_table::resolve
<64, false>(
1045 Sized_symbol
<64>* to
,
1046 const elfcpp::Sym
<64, false>& sym
,
1047 unsigned int st_shndx
,
1049 unsigned int orig_st_shndx
,
1051 const char* version
);
1055 Symbol_table::resolve
<64, true>(
1056 Sized_symbol
<64>* to
,
1057 const elfcpp::Sym
<64, true>& sym
,
1058 unsigned int st_shndx
,
1060 unsigned int orig_st_shndx
,
1062 const char* version
);
1065 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1068 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1069 const Sized_symbol
<32>*);
1072 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1075 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1076 const Sized_symbol
<64>*);
1079 } // End namespace gold.