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 if (to
->source() == Symbol::FROM_OBJECT
)
308 Pluginobj
* obj
= to
->object()->pluginobj();
310 && parameters
->options().plugins()->in_replacement_phase())
312 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
317 // A new weak undefined reference, merging with an old weak
318 // reference, could be a One Definition Rule (ODR) violation --
319 // especially if the types or sizes of the references differ. We'll
320 // store such pairs and look them up later to make sure they
321 // actually refer to the same lines of code. We also check
322 // combinations of weak and strong, which might occur if one case is
323 // inline and the other is not. (Note: not all ODR violations can
324 // be found this way, and not everything this finds is an ODR
325 // violation. But it's helpful to warn about.)
326 if (parameters
->options().detect_odr_violations()
327 && (sym
.get_st_bind() == elfcpp::STB_WEAK
328 || to
->binding() == elfcpp::STB_WEAK
)
329 && orig_st_shndx
!= elfcpp::SHN_UNDEF
330 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
332 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
333 && to
->symsize() != 0
334 && (sym
.get_st_type() != to
->type()
335 || sym
.get_st_size() != to
->symsize())
336 // C does not have a concept of ODR, so we only need to do this
337 // on C++ symbols. These have (mangled) names starting with _Z.
338 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
340 Symbol_location fromloc
341 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
342 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
343 static_cast<off_t
>(to
->value()) };
344 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
345 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
348 // Plugins don't provide a symbol type, so adopt the existing type
349 // if the FROM symbol is from a plugin.
350 elfcpp::STT fromtype
= (object
->pluginobj() != NULL
352 : sym
.get_st_type());
353 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
354 object
->is_dynamic(),
355 st_shndx
, is_ordinary
,
358 bool adjust_common_sizes
;
360 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
361 if (Symbol_table::should_override(to
, frombits
, fromtype
, OBJECT
,
362 object
, &adjust_common_sizes
,
365 elfcpp::STB tobinding
= to
->binding();
366 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
367 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
368 if (adjust_common_sizes
)
370 if (tosize
> to
->symsize())
371 to
->set_symsize(tosize
);
372 if (tovalue
> to
->value())
373 to
->set_value(tovalue
);
377 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
378 // Remember which kind of UNDEF it was for future reference.
379 to
->set_undef_binding(tobinding
);
384 if (adjust_common_sizes
)
386 if (sym
.get_st_size() > tosize
)
387 to
->set_symsize(sym
.get_st_size());
388 if (sym
.get_st_value() > to
->value())
389 to
->set_value(sym
.get_st_value());
393 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
394 // Remember which kind of UNDEF it was.
395 to
->set_undef_binding(sym
.get_st_bind());
397 // The ELF ABI says that even for a reference to a symbol we
398 // merge the visibility.
399 to
->override_visibility(sym
.get_st_visibility());
402 if (adjust_common_sizes
&& parameters
->options().warn_common())
404 if (tosize
> sym
.get_st_size())
405 Symbol_table::report_resolve_problem(false,
406 _("common of '%s' overriding "
409 else if (tosize
< sym
.get_st_size())
410 Symbol_table::report_resolve_problem(false,
411 _("common of '%s' overidden by "
415 Symbol_table::report_resolve_problem(false,
416 _("multiple common of '%s'"),
421 // Handle the core of symbol resolution. This is called with the
422 // existing symbol, TO, and a bitflag describing the new symbol. This
423 // returns true if we should override the existing symbol with the new
424 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
425 // true if we should set the symbol size to the maximum of the TO and
426 // FROM sizes. It handles error conditions.
429 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
430 elfcpp::STT fromtype
, Defined defined
,
431 Object
* object
, bool* adjust_common_sizes
,
434 *adjust_common_sizes
= false;
435 *adjust_dyndef
= false;
438 if (to
->source() == Symbol::IS_UNDEFINED
)
439 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true,
441 else if (to
->source() != Symbol::FROM_OBJECT
)
442 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false,
447 unsigned int shndx
= to
->shndx(&is_ordinary
);
448 tobits
= symbol_to_bits(to
->binding(),
449 to
->object()->is_dynamic(),
455 if ((to
->type() == elfcpp::STT_TLS
) ^ (fromtype
== elfcpp::STT_TLS
)
456 && !to
->is_placeholder())
457 Symbol_table::report_resolve_problem(true,
458 _("symbol '%s' used as both __thread "
460 to
, defined
, object
);
462 // We use a giant switch table for symbol resolution. This code is
463 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
464 // cases; 3) it is easy to change the handling of a particular case.
465 // The alternative would be a series of conditionals, but it is easy
466 // to get the ordering wrong. This could also be done as a table,
467 // but that is no easier to understand than this large switch
470 // These are the values generated by the bit codes.
473 DEF
= global_flag
| regular_flag
| def_flag
,
474 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
475 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
476 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
477 UNDEF
= global_flag
| regular_flag
| undef_flag
,
478 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
479 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
480 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
481 COMMON
= global_flag
| regular_flag
| common_flag
,
482 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
483 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
484 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
487 switch (tobits
* 16 + frombits
)
490 // Two definitions of the same symbol.
492 // If either symbol is defined by an object included using
493 // --just-symbols, then don't warn. This is for compatibility
494 // with the GNU linker. FIXME: This is a hack.
495 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
496 || (object
!= NULL
&& object
->just_symbols()))
499 if (!parameters
->options().muldefs())
500 Symbol_table::report_resolve_problem(true,
501 _("multiple definition of '%s'"),
502 to
, defined
, object
);
505 case WEAK_DEF
* 16 + DEF
:
506 // We've seen a weak definition, and now we see a strong
507 // definition. In the original SVR4 linker, this was treated as
508 // a multiple definition error. In the Solaris linker and the
509 // GNU linker, a weak definition followed by a regular
510 // definition causes the weak definition to be overridden. We
511 // are currently compatible with the GNU linker. In the future
512 // we should add a target specific option to change this.
516 case DYN_DEF
* 16 + DEF
:
517 case DYN_WEAK_DEF
* 16 + DEF
:
518 // We've seen a definition in a dynamic object, and now we see a
519 // definition in a regular object. The definition in the
520 // regular object overrides the definition in the dynamic
524 case UNDEF
* 16 + DEF
:
525 case WEAK_UNDEF
* 16 + DEF
:
526 case DYN_UNDEF
* 16 + DEF
:
527 case DYN_WEAK_UNDEF
* 16 + DEF
:
528 // We've seen an undefined reference, and now we see a
529 // definition. We use the definition.
532 case COMMON
* 16 + DEF
:
533 case WEAK_COMMON
* 16 + DEF
:
534 case DYN_COMMON
* 16 + DEF
:
535 case DYN_WEAK_COMMON
* 16 + DEF
:
536 // We've seen a common symbol and now we see a definition. The
537 // definition overrides.
538 if (parameters
->options().warn_common())
539 Symbol_table::report_resolve_problem(false,
540 _("definition of '%s' overriding "
542 to
, defined
, object
);
545 case DEF
* 16 + WEAK_DEF
:
546 case WEAK_DEF
* 16 + WEAK_DEF
:
547 // We've seen a definition and now we see a weak definition. We
548 // ignore the new weak definition.
551 case DYN_DEF
* 16 + WEAK_DEF
:
552 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
553 // We've seen a dynamic definition and now we see a regular weak
554 // definition. The regular weak definition overrides.
557 case UNDEF
* 16 + WEAK_DEF
:
558 case WEAK_UNDEF
* 16 + WEAK_DEF
:
559 case DYN_UNDEF
* 16 + WEAK_DEF
:
560 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
561 // A weak definition of a currently undefined symbol.
564 case COMMON
* 16 + WEAK_DEF
:
565 case WEAK_COMMON
* 16 + WEAK_DEF
:
566 // A weak definition does not override a common definition.
569 case DYN_COMMON
* 16 + WEAK_DEF
:
570 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
571 // A weak definition does override a definition in a dynamic
573 if (parameters
->options().warn_common())
574 Symbol_table::report_resolve_problem(false,
575 _("definition of '%s' overriding "
576 "dynamic common definition"),
577 to
, defined
, object
);
580 case DEF
* 16 + DYN_DEF
:
581 case WEAK_DEF
* 16 + DYN_DEF
:
582 case DYN_DEF
* 16 + DYN_DEF
:
583 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
584 // Ignore a dynamic definition if we already have a definition.
587 case UNDEF
* 16 + DYN_DEF
:
588 case DYN_UNDEF
* 16 + DYN_DEF
:
589 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
590 // Use a dynamic definition if we have a reference.
593 case WEAK_UNDEF
* 16 + DYN_DEF
:
594 // When overriding a weak undef by a dynamic definition,
595 // we need to remember that the original undef was weak.
596 *adjust_dyndef
= true;
599 case COMMON
* 16 + DYN_DEF
:
600 case WEAK_COMMON
* 16 + DYN_DEF
:
601 case DYN_COMMON
* 16 + DYN_DEF
:
602 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
603 // Ignore a dynamic definition if we already have a common
607 case DEF
* 16 + DYN_WEAK_DEF
:
608 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
609 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
610 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
611 // Ignore a weak dynamic definition if we already have a
615 case UNDEF
* 16 + DYN_WEAK_DEF
:
616 // When overriding an undef by a dynamic weak definition,
617 // we need to remember that the original undef was not weak.
618 *adjust_dyndef
= true;
621 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
622 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
623 // Use a weak dynamic definition if we have a reference.
626 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
627 // When overriding a weak undef by a dynamic definition,
628 // we need to remember that the original undef was weak.
629 *adjust_dyndef
= true;
632 case COMMON
* 16 + DYN_WEAK_DEF
:
633 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
634 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
635 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
636 // Ignore a weak dynamic definition if we already have a common
640 case DEF
* 16 + UNDEF
:
641 case WEAK_DEF
* 16 + UNDEF
:
642 case UNDEF
* 16 + UNDEF
:
643 // A new undefined reference tells us nothing.
646 case DYN_DEF
* 16 + UNDEF
:
647 case DYN_WEAK_DEF
* 16 + UNDEF
:
648 // For a dynamic def, we need to remember which kind of undef we see.
649 *adjust_dyndef
= true;
652 case WEAK_UNDEF
* 16 + UNDEF
:
653 case DYN_UNDEF
* 16 + UNDEF
:
654 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
655 // A strong undef overrides a dynamic or weak undef.
658 case COMMON
* 16 + UNDEF
:
659 case WEAK_COMMON
* 16 + UNDEF
:
660 case DYN_COMMON
* 16 + UNDEF
:
661 case DYN_WEAK_COMMON
* 16 + UNDEF
:
662 // A new undefined reference tells us nothing.
665 case DEF
* 16 + WEAK_UNDEF
:
666 case WEAK_DEF
* 16 + WEAK_UNDEF
:
667 case UNDEF
* 16 + WEAK_UNDEF
:
668 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
669 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
670 case COMMON
* 16 + WEAK_UNDEF
:
671 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
672 case DYN_COMMON
* 16 + WEAK_UNDEF
:
673 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
674 // A new weak undefined reference tells us nothing unless the
675 // exisiting symbol is a dynamic weak reference.
678 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
679 // A new weak reference overrides an existing dynamic weak reference.
680 // This is necessary because a dynamic weak reference remembers
681 // the old binding, which may not be weak. If we keeps the existing
682 // dynamic weak reference, the weakness may be dropped in the output.
685 case DYN_DEF
* 16 + WEAK_UNDEF
:
686 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
687 // For a dynamic def, we need to remember which kind of undef we see.
688 *adjust_dyndef
= true;
691 case DEF
* 16 + DYN_UNDEF
:
692 case WEAK_DEF
* 16 + DYN_UNDEF
:
693 case DYN_DEF
* 16 + DYN_UNDEF
:
694 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
695 case UNDEF
* 16 + DYN_UNDEF
:
696 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
697 case DYN_UNDEF
* 16 + DYN_UNDEF
:
698 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
699 case COMMON
* 16 + DYN_UNDEF
:
700 case WEAK_COMMON
* 16 + DYN_UNDEF
:
701 case DYN_COMMON
* 16 + DYN_UNDEF
:
702 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
703 // A new dynamic undefined reference tells us nothing.
706 case DEF
* 16 + DYN_WEAK_UNDEF
:
707 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
708 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
709 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
710 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
711 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
712 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
713 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
714 case COMMON
* 16 + DYN_WEAK_UNDEF
:
715 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
716 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
717 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
718 // A new weak dynamic undefined reference tells us nothing.
721 case DEF
* 16 + COMMON
:
722 // A common symbol does not override a definition.
723 if (parameters
->options().warn_common())
724 Symbol_table::report_resolve_problem(false,
725 _("common '%s' overridden by "
726 "previous definition"),
727 to
, defined
, object
);
730 case WEAK_DEF
* 16 + COMMON
:
731 case DYN_DEF
* 16 + COMMON
:
732 case DYN_WEAK_DEF
* 16 + COMMON
:
733 // A common symbol does override a weak definition or a dynamic
737 case UNDEF
* 16 + COMMON
:
738 case WEAK_UNDEF
* 16 + COMMON
:
739 case DYN_UNDEF
* 16 + COMMON
:
740 case DYN_WEAK_UNDEF
* 16 + COMMON
:
741 // A common symbol is a definition for a reference.
744 case COMMON
* 16 + COMMON
:
745 // Set the size to the maximum.
746 *adjust_common_sizes
= true;
749 case WEAK_COMMON
* 16 + COMMON
:
750 // I'm not sure just what a weak common symbol means, but
751 // presumably it can be overridden by a regular common symbol.
754 case DYN_COMMON
* 16 + COMMON
:
755 case DYN_WEAK_COMMON
* 16 + COMMON
:
756 // Use the real common symbol, but adjust the size if necessary.
757 *adjust_common_sizes
= true;
760 case DEF
* 16 + WEAK_COMMON
:
761 case WEAK_DEF
* 16 + WEAK_COMMON
:
762 case DYN_DEF
* 16 + WEAK_COMMON
:
763 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
764 // Whatever a weak common symbol is, it won't override a
768 case UNDEF
* 16 + WEAK_COMMON
:
769 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
770 case DYN_UNDEF
* 16 + WEAK_COMMON
:
771 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
772 // A weak common symbol is better than an undefined symbol.
775 case COMMON
* 16 + WEAK_COMMON
:
776 case WEAK_COMMON
* 16 + WEAK_COMMON
:
777 case DYN_COMMON
* 16 + WEAK_COMMON
:
778 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
779 // Ignore a weak common symbol in the presence of a real common
783 case DEF
* 16 + DYN_COMMON
:
784 case WEAK_DEF
* 16 + DYN_COMMON
:
785 case DYN_DEF
* 16 + DYN_COMMON
:
786 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
787 // Ignore a dynamic common symbol in the presence of a
791 case UNDEF
* 16 + DYN_COMMON
:
792 case WEAK_UNDEF
* 16 + DYN_COMMON
:
793 case DYN_UNDEF
* 16 + DYN_COMMON
:
794 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
795 // A dynamic common symbol is a definition of sorts.
798 case COMMON
* 16 + DYN_COMMON
:
799 case WEAK_COMMON
* 16 + DYN_COMMON
:
800 case DYN_COMMON
* 16 + DYN_COMMON
:
801 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
802 // Set the size to the maximum.
803 *adjust_common_sizes
= true;
806 case DEF
* 16 + DYN_WEAK_COMMON
:
807 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
808 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
809 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
810 // A common symbol is ignored in the face of a definition.
813 case UNDEF
* 16 + DYN_WEAK_COMMON
:
814 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
815 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
816 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
817 // I guess a weak common symbol is better than a definition.
820 case COMMON
* 16 + DYN_WEAK_COMMON
:
821 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
822 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
823 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
824 // Set the size to the maximum.
825 *adjust_common_sizes
= true;
833 // Issue an error or warning due to symbol resolution. IS_ERROR
834 // indicates an error rather than a warning. MSG is the error
835 // message; it is expected to have a %s for the symbol name. TO is
836 // the existing symbol. DEFINED/OBJECT is where the new symbol was
839 // FIXME: We should have better location information here. When the
840 // symbol is defined, we should be able to pull the location from the
841 // debug info if there is any.
844 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
845 const Symbol
* to
, Defined defined
,
848 std::string
demangled(to
->demangled_name());
849 size_t len
= strlen(msg
) + demangled
.length() + 10;
850 char* buf
= new char[len
];
851 snprintf(buf
, len
, msg
, demangled
.c_str());
857 objname
= object
->name().c_str();
860 objname
= _("COPY reloc");
864 objname
= _("command line");
867 objname
= _("linker script");
870 case INCREMENTAL_BASE
:
871 objname
= _("linker defined");
878 gold_error("%s: %s", objname
, buf
);
880 gold_warning("%s: %s", objname
, buf
);
884 if (to
->source() == Symbol::FROM_OBJECT
)
885 objname
= to
->object()->name().c_str();
887 objname
= _("command line");
888 gold_info("%s: %s: previous definition here", program_name
, objname
);
891 // A special case of should_override which is only called for a strong
892 // defined symbol from a regular object file. This is used when
893 // defining special symbols.
896 Symbol_table::should_override_with_special(const Symbol
* to
,
897 elfcpp::STT fromtype
,
900 bool adjust_common_sizes
;
902 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
903 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
904 NULL
, &adjust_common_sizes
,
906 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
910 // Override symbol base with a special symbol.
913 Symbol::override_base_with_special(const Symbol
* from
)
915 bool same_name
= this->name_
== from
->name_
;
916 gold_assert(same_name
|| this->has_alias());
918 this->source_
= from
->source_
;
919 switch (from
->source_
)
922 this->u_
.from_object
= from
->u_
.from_object
;
925 this->u_
.in_output_data
= from
->u_
.in_output_data
;
927 case IN_OUTPUT_SEGMENT
:
928 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
940 // When overriding a versioned symbol with a special symbol, we
941 // may be changing the version. This will happen if we see a
942 // special symbol such as "_end" defined in a shared object with
943 // one version (from a version script), but we want to define it
944 // here with a different version (from a different version
946 this->version_
= from
->version_
;
948 this->type_
= from
->type_
;
949 this->binding_
= from
->binding_
;
950 this->override_visibility(from
->visibility_
);
951 this->nonvis_
= from
->nonvis_
;
953 // Special symbols are always considered to be regular symbols.
954 this->in_reg_
= true;
956 if (from
->needs_dynsym_entry_
)
957 this->needs_dynsym_entry_
= true;
958 if (from
->needs_dynsym_value_
)
959 this->needs_dynsym_value_
= true;
961 this->is_predefined_
= from
->is_predefined_
;
963 // We shouldn't see these flags. If we do, we need to handle them
965 gold_assert(!from
->is_forwarder_
);
966 gold_assert(!from
->has_plt_offset());
967 gold_assert(!from
->has_warning_
);
968 gold_assert(!from
->is_copied_from_dynobj_
);
969 gold_assert(!from
->is_forced_local_
);
972 // Override a symbol with a special symbol.
976 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
978 this->override_base_with_special(from
);
979 this->value_
= from
->value_
;
980 this->symsize_
= from
->symsize_
;
983 // Override TOSYM with the special symbol FROMSYM. This handles all
988 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
989 const Sized_symbol
<size
>* fromsym
)
991 tosym
->override_with_special(fromsym
);
992 if (tosym
->has_alias())
994 Symbol
* sym
= this->weak_aliases_
[tosym
];
995 gold_assert(sym
!= NULL
);
996 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
999 ssym
->override_with_special(fromsym
);
1000 sym
= this->weak_aliases_
[ssym
];
1001 gold_assert(sym
!= NULL
);
1002 ssym
= this->get_sized_symbol
<size
>(sym
);
1004 while (ssym
!= tosym
);
1006 if (tosym
->binding() == elfcpp::STB_LOCAL
1007 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1008 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1009 && (tosym
->binding() == elfcpp::STB_GLOBAL
1010 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1011 || tosym
->binding() == elfcpp::STB_WEAK
)
1012 && !parameters
->options().relocatable()))
1013 this->force_local(tosym
);
1016 // Instantiate the templates we need. We could use the configure
1017 // script to restrict this to only the ones needed for implemented
1020 // We have to instantiate both big and little endian versions because
1021 // these are used by other templates that depends on size only.
1023 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1026 Symbol_table::resolve
<32, false>(
1027 Sized_symbol
<32>* to
,
1028 const elfcpp::Sym
<32, false>& sym
,
1029 unsigned int st_shndx
,
1031 unsigned int orig_st_shndx
,
1033 const char* version
);
1037 Symbol_table::resolve
<32, true>(
1038 Sized_symbol
<32>* to
,
1039 const elfcpp::Sym
<32, true>& sym
,
1040 unsigned int st_shndx
,
1042 unsigned int orig_st_shndx
,
1044 const char* version
);
1047 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1050 Symbol_table::resolve
<64, false>(
1051 Sized_symbol
<64>* to
,
1052 const elfcpp::Sym
<64, false>& sym
,
1053 unsigned int st_shndx
,
1055 unsigned int orig_st_shndx
,
1057 const char* version
);
1061 Symbol_table::resolve
<64, true>(
1062 Sized_symbol
<64>* to
,
1063 const elfcpp::Sym
<64, true>& sym
,
1064 unsigned int st_shndx
,
1066 unsigned int orig_st_shndx
,
1068 const char* version
);
1071 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1074 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1075 const Sized_symbol
<32>*);
1078 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1081 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1082 const Sized_symbol
<64>*);
1085 } // End namespace gold.