1 // resolve.cc -- symbol resolution for gold
3 // Copyright (C) 2006-2018 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->u1_
.object
= object
;
96 this->override_version(version
);
97 this->u2_
.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"));
199 // Any target which wants to handle STB_LOOS, etc., needs to
200 // define a resolve method.
201 gold_error(_("unsupported symbol binding %d"), static_cast<int>(binding
));
206 bits
|= dynamic_flag
;
208 bits
|= regular_flag
;
212 case elfcpp::SHN_UNDEF
:
216 case elfcpp::SHN_COMMON
:
222 if (!is_ordinary
&& Symbol::is_common_shndx(shndx
))
232 // Resolve a symbol. This is called the second and subsequent times
233 // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
234 // section index for SYM, possibly adjusted for many sections.
235 // IS_ORDINARY is whether ST_SHNDX is a normal section index rather
236 // than a special code. ORIG_ST_SHNDX is the original section index,
237 // before any munging because of discarded sections, except that all
238 // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
239 // the version of SYM.
241 template<int size
, bool big_endian
>
243 Symbol_table::resolve(Sized_symbol
<size
>* to
,
244 const elfcpp::Sym
<size
, big_endian
>& sym
,
245 unsigned int st_shndx
, bool is_ordinary
,
246 unsigned int orig_st_shndx
,
247 Object
* object
, const char* version
,
248 bool is_default_version
)
251 const unsigned int to_shndx
= to
->shndx(&to_is_ordinary
);
253 // It's possible for a symbol to be defined in an object file
254 // using .symver to give it a version, and for there to also be
255 // a linker script giving that symbol the same version. We
256 // don't want to give a multiple-definition error for this
257 // harmless redefinition.
258 if (to
->source() == Symbol::FROM_OBJECT
259 && to
->object() == object
263 && to_shndx
== st_shndx
264 && to
->value() == sym
.get_st_value())
267 // Likewise for an absolute symbol defined twice with the same value.
269 && st_shndx
== elfcpp::SHN_ABS
271 && to_shndx
== elfcpp::SHN_ABS
272 && to
->value() == sym
.get_st_value())
275 if (parameters
->target().has_resolve())
277 Sized_target
<size
, big_endian
>* sized_target
;
278 sized_target
= parameters
->sized_target
<size
, big_endian
>();
279 if (sized_target
->resolve(to
, sym
, object
, version
))
283 if (!object
->is_dynamic())
285 if (sym
.get_st_type() == elfcpp::STT_COMMON
286 && (is_ordinary
|| !Symbol::is_common_shndx(st_shndx
)))
288 gold_warning(_("STT_COMMON symbol '%s' in %s "
289 "is not in a common section"),
290 to
->demangled_name().c_str(),
291 to
->object()->name().c_str());
294 // Record that we've seen this symbol in a regular object.
297 else if (st_shndx
== elfcpp::SHN_UNDEF
298 && (to
->visibility() == elfcpp::STV_HIDDEN
299 || to
->visibility() == elfcpp::STV_INTERNAL
))
301 // The symbol is hidden, so a reference from a shared object
302 // cannot bind to it. We tried issuing a warning in this case,
303 // but that produces false positives when the symbol is
304 // actually resolved in a different shared object (PR 15574).
309 // Record that we've seen this symbol in a dynamic object.
313 // Record if we've seen this symbol in a real ELF object (i.e., the
314 // symbol is referenced from outside the world known to the plugin).
315 if (object
->pluginobj() == NULL
&& !object
->is_dynamic())
316 to
->set_in_real_elf();
318 // If we're processing replacement files, allow new symbols to override
319 // the placeholders from the plugin objects.
320 // Treat common symbols specially since it is possible that an ELF
321 // file increased the size of the alignment.
322 if (to
->source() == Symbol::FROM_OBJECT
)
324 Pluginobj
* obj
= to
->object()->pluginobj();
326 && parameters
->options().plugins()->in_replacement_phase())
328 bool adjust_common
= false;
329 typename Sized_symbol
<size
>::Size_type tosize
= 0;
330 typename Sized_symbol
<size
>::Value_type tovalue
= 0;
332 && !is_ordinary
&& Symbol::is_common_shndx(st_shndx
))
334 adjust_common
= true;
335 tosize
= to
->symsize();
336 tovalue
= to
->value();
338 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
341 if (tosize
> to
->symsize())
342 to
->set_symsize(tosize
);
343 if (tovalue
> to
->value())
344 to
->set_value(tovalue
);
350 // A new weak undefined reference, merging with an old weak
351 // reference, could be a One Definition Rule (ODR) violation --
352 // especially if the types or sizes of the references differ. We'll
353 // store such pairs and look them up later to make sure they
354 // actually refer to the same lines of code. We also check
355 // combinations of weak and strong, which might occur if one case is
356 // inline and the other is not. (Note: not all ODR violations can
357 // be found this way, and not everything this finds is an ODR
358 // violation. But it's helpful to warn about.)
359 if (parameters
->options().detect_odr_violations()
360 && (sym
.get_st_bind() == elfcpp::STB_WEAK
361 || to
->binding() == elfcpp::STB_WEAK
)
362 && orig_st_shndx
!= elfcpp::SHN_UNDEF
364 && to_shndx
!= elfcpp::SHN_UNDEF
365 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
366 && to
->symsize() != 0
367 && (sym
.get_st_type() != to
->type()
368 || sym
.get_st_size() != to
->symsize())
369 // C does not have a concept of ODR, so we only need to do this
370 // on C++ symbols. These have (mangled) names starting with _Z.
371 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
373 Symbol_location fromloc
374 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
375 Symbol_location toloc
= { to
->object(), to_shndx
,
376 static_cast<off_t
>(to
->value()) };
377 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
378 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
381 // Plugins don't provide a symbol type, so adopt the existing type
382 // if the FROM symbol is from a plugin.
383 elfcpp::STT fromtype
= (object
->pluginobj() != NULL
385 : sym
.get_st_type());
386 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
387 object
->is_dynamic(),
388 st_shndx
, is_ordinary
);
390 bool adjust_common_sizes
;
392 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
393 if (Symbol_table::should_override(to
, frombits
, fromtype
, OBJECT
,
394 object
, &adjust_common_sizes
,
395 &adjust_dyndef
, is_default_version
))
397 elfcpp::STB tobinding
= to
->binding();
398 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
399 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
400 if (adjust_common_sizes
)
402 if (tosize
> to
->symsize())
403 to
->set_symsize(tosize
);
404 if (tovalue
> to
->value())
405 to
->set_value(tovalue
);
409 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
410 // Remember which kind of UNDEF it was for future reference.
411 to
->set_undef_binding(tobinding
);
416 if (adjust_common_sizes
)
418 if (sym
.get_st_size() > tosize
)
419 to
->set_symsize(sym
.get_st_size());
420 if (sym
.get_st_value() > to
->value())
421 to
->set_value(sym
.get_st_value());
425 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
426 // Remember which kind of UNDEF it was.
427 to
->set_undef_binding(sym
.get_st_bind());
429 // The ELF ABI says that even for a reference to a symbol we
430 // merge the visibility.
431 to
->override_visibility(sym
.get_st_visibility());
434 if (adjust_common_sizes
&& parameters
->options().warn_common())
436 if (tosize
> sym
.get_st_size())
437 Symbol_table::report_resolve_problem(false,
438 _("common of '%s' overriding "
441 else if (tosize
< sym
.get_st_size())
442 Symbol_table::report_resolve_problem(false,
443 _("common of '%s' overidden by "
447 Symbol_table::report_resolve_problem(false,
448 _("multiple common of '%s'"),
453 // Handle the core of symbol resolution. This is called with the
454 // existing symbol, TO, and a bitflag describing the new symbol. This
455 // returns true if we should override the existing symbol with the new
456 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
457 // true if we should set the symbol size to the maximum of the TO and
458 // FROM sizes. It handles error conditions.
461 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
462 elfcpp::STT fromtype
, Defined defined
,
463 Object
* object
, bool* adjust_common_sizes
,
464 bool* adjust_dyndef
, bool is_default_version
)
466 *adjust_common_sizes
= false;
467 *adjust_dyndef
= false;
470 if (to
->source() == Symbol::IS_UNDEFINED
)
471 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true);
472 else if (to
->source() != Symbol::FROM_OBJECT
)
473 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false);
477 unsigned int shndx
= to
->shndx(&is_ordinary
);
478 tobits
= symbol_to_bits(to
->binding(),
479 to
->object()->is_dynamic(),
484 if ((to
->type() == elfcpp::STT_TLS
) ^ (fromtype
== elfcpp::STT_TLS
)
485 && !to
->is_placeholder())
486 Symbol_table::report_resolve_problem(true,
487 _("symbol '%s' used as both __thread "
489 to
, defined
, object
);
491 // We use a giant switch table for symbol resolution. This code is
492 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
493 // cases; 3) it is easy to change the handling of a particular case.
494 // The alternative would be a series of conditionals, but it is easy
495 // to get the ordering wrong. This could also be done as a table,
496 // but that is no easier to understand than this large switch
499 // These are the values generated by the bit codes.
502 DEF
= global_flag
| regular_flag
| def_flag
,
503 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
504 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
505 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
506 UNDEF
= global_flag
| regular_flag
| undef_flag
,
507 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
508 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
509 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
510 COMMON
= global_flag
| regular_flag
| common_flag
,
511 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
512 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
513 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
516 switch (tobits
* 16 + frombits
)
519 // Two definitions of the same symbol.
521 // If either symbol is defined by an object included using
522 // --just-symbols, then don't warn. This is for compatibility
523 // with the GNU linker. FIXME: This is a hack.
524 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
525 || (object
!= NULL
&& object
->just_symbols()))
528 if (!parameters
->options().muldefs())
529 Symbol_table::report_resolve_problem(true,
530 _("multiple definition of '%s'"),
531 to
, defined
, object
);
534 case WEAK_DEF
* 16 + DEF
:
535 // We've seen a weak definition, and now we see a strong
536 // definition. In the original SVR4 linker, this was treated as
537 // a multiple definition error. In the Solaris linker and the
538 // GNU linker, a weak definition followed by a regular
539 // definition causes the weak definition to be overridden. We
540 // are currently compatible with the GNU linker. In the future
541 // we should add a target specific option to change this.
545 case DYN_DEF
* 16 + DEF
:
546 case DYN_WEAK_DEF
* 16 + DEF
:
547 // We've seen a definition in a dynamic object, and now we see a
548 // definition in a regular object. The definition in the
549 // regular object overrides the definition in the dynamic
553 case UNDEF
* 16 + DEF
:
554 case WEAK_UNDEF
* 16 + DEF
:
555 case DYN_UNDEF
* 16 + DEF
:
556 case DYN_WEAK_UNDEF
* 16 + DEF
:
557 // We've seen an undefined reference, and now we see a
558 // definition. We use the definition.
561 case COMMON
* 16 + DEF
:
562 case WEAK_COMMON
* 16 + DEF
:
563 case DYN_COMMON
* 16 + DEF
:
564 case DYN_WEAK_COMMON
* 16 + DEF
:
565 // We've seen a common symbol and now we see a definition. The
566 // definition overrides.
567 if (parameters
->options().warn_common())
568 Symbol_table::report_resolve_problem(false,
569 _("definition of '%s' overriding "
571 to
, defined
, object
);
574 case DEF
* 16 + WEAK_DEF
:
575 case WEAK_DEF
* 16 + WEAK_DEF
:
576 // We've seen a definition and now we see a weak definition. We
577 // ignore the new weak definition.
580 case DYN_DEF
* 16 + WEAK_DEF
:
581 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
582 // We've seen a dynamic definition and now we see a regular weak
583 // definition. The regular weak definition overrides.
586 case UNDEF
* 16 + WEAK_DEF
:
587 case WEAK_UNDEF
* 16 + WEAK_DEF
:
588 case DYN_UNDEF
* 16 + WEAK_DEF
:
589 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
590 // A weak definition of a currently undefined symbol.
593 case COMMON
* 16 + WEAK_DEF
:
594 case WEAK_COMMON
* 16 + WEAK_DEF
:
595 // A weak definition does not override a common definition.
598 case DYN_COMMON
* 16 + WEAK_DEF
:
599 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
600 // A weak definition does override a definition in a dynamic
602 if (parameters
->options().warn_common())
603 Symbol_table::report_resolve_problem(false,
604 _("definition of '%s' overriding "
605 "dynamic common definition"),
606 to
, defined
, object
);
609 case DEF
* 16 + DYN_DEF
:
610 case WEAK_DEF
* 16 + DYN_DEF
:
611 // Ignore a dynamic definition if we already have a definition.
614 case DYN_DEF
* 16 + DYN_DEF
:
615 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
616 // Ignore a dynamic definition if we already have a definition,
617 // unless the existing definition is an unversioned definition
618 // in the same dynamic object, and the new definition is a
620 if (to
->object() == object
621 && to
->version() == NULL
622 && is_default_version
)
626 case UNDEF
* 16 + DYN_DEF
:
627 case DYN_UNDEF
* 16 + DYN_DEF
:
628 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
629 // Use a dynamic definition if we have a reference.
632 case WEAK_UNDEF
* 16 + DYN_DEF
:
633 // When overriding a weak undef by a dynamic definition,
634 // we need to remember that the original undef was weak.
635 *adjust_dyndef
= true;
638 case COMMON
* 16 + DYN_DEF
:
639 case WEAK_COMMON
* 16 + DYN_DEF
:
640 case DYN_COMMON
* 16 + DYN_DEF
:
641 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
642 // Ignore a dynamic definition if we already have a common
646 case DEF
* 16 + DYN_WEAK_DEF
:
647 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
648 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
649 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
650 // Ignore a weak dynamic definition if we already have a
654 case UNDEF
* 16 + DYN_WEAK_DEF
:
655 // When overriding an undef by a dynamic weak definition,
656 // we need to remember that the original undef was not weak.
657 *adjust_dyndef
= true;
660 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
661 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
662 // Use a weak dynamic definition if we have a reference.
665 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
666 // When overriding a weak undef by a dynamic definition,
667 // we need to remember that the original undef was weak.
668 *adjust_dyndef
= true;
671 case COMMON
* 16 + DYN_WEAK_DEF
:
672 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
673 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
674 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
675 // Ignore a weak dynamic definition if we already have a common
679 case DEF
* 16 + UNDEF
:
680 case WEAK_DEF
* 16 + UNDEF
:
681 case UNDEF
* 16 + UNDEF
:
682 // A new undefined reference tells us nothing.
685 case DYN_DEF
* 16 + UNDEF
:
686 case DYN_WEAK_DEF
* 16 + UNDEF
:
687 // For a dynamic def, we need to remember which kind of undef we see.
688 *adjust_dyndef
= true;
691 case WEAK_UNDEF
* 16 + UNDEF
:
692 case DYN_UNDEF
* 16 + UNDEF
:
693 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
694 // A strong undef overrides a dynamic or weak undef.
697 case COMMON
* 16 + UNDEF
:
698 case WEAK_COMMON
* 16 + UNDEF
:
699 case DYN_COMMON
* 16 + UNDEF
:
700 case DYN_WEAK_COMMON
* 16 + UNDEF
:
701 // A new undefined reference tells us nothing.
704 case DEF
* 16 + WEAK_UNDEF
:
705 case WEAK_DEF
* 16 + WEAK_UNDEF
:
706 case UNDEF
* 16 + WEAK_UNDEF
:
707 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
708 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
709 case COMMON
* 16 + WEAK_UNDEF
:
710 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
711 case DYN_COMMON
* 16 + WEAK_UNDEF
:
712 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
713 // A new weak undefined reference tells us nothing unless the
714 // exisiting symbol is a dynamic weak reference.
717 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
718 // A new weak reference overrides an existing dynamic weak reference.
719 // This is necessary because a dynamic weak reference remembers
720 // the old binding, which may not be weak. If we keeps the existing
721 // dynamic weak reference, the weakness may be dropped in the output.
724 case DYN_DEF
* 16 + WEAK_UNDEF
:
725 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
726 // For a dynamic def, we need to remember which kind of undef we see.
727 *adjust_dyndef
= true;
730 case DEF
* 16 + DYN_UNDEF
:
731 case WEAK_DEF
* 16 + DYN_UNDEF
:
732 case DYN_DEF
* 16 + DYN_UNDEF
:
733 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
734 case UNDEF
* 16 + DYN_UNDEF
:
735 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
736 case DYN_UNDEF
* 16 + DYN_UNDEF
:
737 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
738 case COMMON
* 16 + DYN_UNDEF
:
739 case WEAK_COMMON
* 16 + DYN_UNDEF
:
740 case DYN_COMMON
* 16 + DYN_UNDEF
:
741 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
742 // A new dynamic undefined reference tells us nothing.
745 case DEF
* 16 + DYN_WEAK_UNDEF
:
746 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
747 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
748 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
749 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
750 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
751 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
752 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
753 case COMMON
* 16 + DYN_WEAK_UNDEF
:
754 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
755 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
756 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
757 // A new weak dynamic undefined reference tells us nothing.
760 case DEF
* 16 + COMMON
:
761 // A common symbol does not override a definition.
762 if (parameters
->options().warn_common())
763 Symbol_table::report_resolve_problem(false,
764 _("common '%s' overridden by "
765 "previous definition"),
766 to
, defined
, object
);
769 case WEAK_DEF
* 16 + COMMON
:
770 case DYN_DEF
* 16 + COMMON
:
771 case DYN_WEAK_DEF
* 16 + COMMON
:
772 // A common symbol does override a weak definition or a dynamic
776 case UNDEF
* 16 + COMMON
:
777 case WEAK_UNDEF
* 16 + COMMON
:
778 case DYN_UNDEF
* 16 + COMMON
:
779 case DYN_WEAK_UNDEF
* 16 + COMMON
:
780 // A common symbol is a definition for a reference.
783 case COMMON
* 16 + COMMON
:
784 // Set the size to the maximum.
785 *adjust_common_sizes
= true;
788 case WEAK_COMMON
* 16 + COMMON
:
789 // I'm not sure just what a weak common symbol means, but
790 // presumably it can be overridden by a regular common symbol.
793 case DYN_COMMON
* 16 + COMMON
:
794 case DYN_WEAK_COMMON
* 16 + COMMON
:
795 // Use the real common symbol, but adjust the size if necessary.
796 *adjust_common_sizes
= true;
799 case DEF
* 16 + WEAK_COMMON
:
800 case WEAK_DEF
* 16 + WEAK_COMMON
:
801 case DYN_DEF
* 16 + WEAK_COMMON
:
802 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
803 // Whatever a weak common symbol is, it won't override a
807 case UNDEF
* 16 + WEAK_COMMON
:
808 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
809 case DYN_UNDEF
* 16 + WEAK_COMMON
:
810 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
811 // A weak common symbol is better than an undefined symbol.
814 case COMMON
* 16 + WEAK_COMMON
:
815 case WEAK_COMMON
* 16 + WEAK_COMMON
:
816 case DYN_COMMON
* 16 + WEAK_COMMON
:
817 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
818 // Ignore a weak common symbol in the presence of a real common
822 case DEF
* 16 + DYN_COMMON
:
823 case WEAK_DEF
* 16 + DYN_COMMON
:
824 case DYN_DEF
* 16 + DYN_COMMON
:
825 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
826 // Ignore a dynamic common symbol in the presence of a
830 case UNDEF
* 16 + DYN_COMMON
:
831 case WEAK_UNDEF
* 16 + DYN_COMMON
:
832 case DYN_UNDEF
* 16 + DYN_COMMON
:
833 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
834 // A dynamic common symbol is a definition of sorts.
837 case COMMON
* 16 + DYN_COMMON
:
838 case WEAK_COMMON
* 16 + DYN_COMMON
:
839 case DYN_COMMON
* 16 + DYN_COMMON
:
840 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
841 // Set the size to the maximum.
842 *adjust_common_sizes
= true;
845 case DEF
* 16 + DYN_WEAK_COMMON
:
846 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
847 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
848 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
849 // A common symbol is ignored in the face of a definition.
852 case UNDEF
* 16 + DYN_WEAK_COMMON
:
853 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
854 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
855 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
856 // I guess a weak common symbol is better than a definition.
859 case COMMON
* 16 + DYN_WEAK_COMMON
:
860 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
861 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
862 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
863 // Set the size to the maximum.
864 *adjust_common_sizes
= true;
872 // Issue an error or warning due to symbol resolution. IS_ERROR
873 // indicates an error rather than a warning. MSG is the error
874 // message; it is expected to have a %s for the symbol name. TO is
875 // the existing symbol. DEFINED/OBJECT is where the new symbol was
878 // FIXME: We should have better location information here. When the
879 // symbol is defined, we should be able to pull the location from the
880 // debug info if there is any.
883 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
884 const Symbol
* to
, Defined defined
,
887 std::string
demangled(to
->demangled_name());
888 size_t len
= strlen(msg
) + demangled
.length() + 10;
889 char* buf
= new char[len
];
890 snprintf(buf
, len
, msg
, demangled
.c_str());
896 objname
= object
->name().c_str();
899 objname
= _("COPY reloc");
903 objname
= _("command line");
906 objname
= _("linker script");
909 case INCREMENTAL_BASE
:
910 objname
= _("linker defined");
917 gold_error("%s: %s", objname
, buf
);
919 gold_warning("%s: %s", objname
, buf
);
923 if (to
->source() == Symbol::FROM_OBJECT
)
924 objname
= to
->object()->name().c_str();
926 objname
= _("command line");
927 gold_info("%s: %s: previous definition here", program_name
, objname
);
930 // Completely override existing symbol. Everything bar name_,
931 // version_, and is_forced_local_ flag are copied. version_ is
932 // cleared if from->version_ is clear. Returns true if this symbol
933 // should be forced local.
935 Symbol::clone(const Symbol
* from
)
937 // Don't allow cloning after dynamic linking info is attached to symbols.
938 // We aren't prepared to merge such.
939 gold_assert(!this->has_symtab_index() && !from
->has_symtab_index());
940 gold_assert(!this->has_dynsym_index() && !from
->has_dynsym_index());
941 gold_assert(this->got_offset_list() == NULL
942 && from
->got_offset_list() == NULL
);
943 gold_assert(!this->has_plt_offset() && !from
->has_plt_offset());
946 this->version_
= from
->version_
;
947 this->u1_
= from
->u1_
;
948 this->u2_
= from
->u2_
;
949 this->type_
= from
->type_
;
950 this->binding_
= from
->binding_
;
951 this->visibility_
= from
->visibility_
;
952 this->nonvis_
= from
->nonvis_
;
953 this->source_
= from
->source_
;
954 this->is_def_
= from
->is_def_
;
955 this->is_forwarder_
= from
->is_forwarder_
;
956 this->has_alias_
= from
->has_alias_
;
957 this->needs_dynsym_entry_
= from
->needs_dynsym_entry_
;
958 this->in_reg_
= from
->in_reg_
;
959 this->in_dyn_
= from
->in_dyn_
;
960 this->needs_dynsym_value_
= from
->needs_dynsym_value_
;
961 this->has_warning_
= from
->has_warning_
;
962 this->is_copied_from_dynobj_
= from
->is_copied_from_dynobj_
;
963 this->is_ordinary_shndx_
= from
->is_ordinary_shndx_
;
964 this->in_real_elf_
= from
->in_real_elf_
;
965 this->is_defined_in_discarded_section_
966 = from
->is_defined_in_discarded_section_
;
967 this->undef_binding_set_
= from
->undef_binding_set_
;
968 this->undef_binding_weak_
= from
->undef_binding_weak_
;
969 this->is_predefined_
= from
->is_predefined_
;
970 this->is_protected_
= from
->is_protected_
;
971 this->non_zero_localentry_
= from
->non_zero_localentry_
;
973 return !this->is_forced_local_
&& from
->is_forced_local_
;
978 Sized_symbol
<size
>::clone(const Sized_symbol
<size
>* from
)
980 this->value_
= from
->value_
;
981 this->symsize_
= from
->symsize_
;
982 return Symbol::clone(from
);
985 // A special case of should_override which is only called for a strong
986 // defined symbol from a regular object file. This is used when
987 // defining special symbols.
990 Symbol_table::should_override_with_special(const Symbol
* to
,
991 elfcpp::STT fromtype
,
994 bool adjust_common_sizes
;
996 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
997 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
998 NULL
, &adjust_common_sizes
,
999 &adjust_dyn_def
, false);
1000 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
1004 // Override symbol base with a special symbol.
1007 Symbol::override_base_with_special(const Symbol
* from
)
1009 bool same_name
= this->name_
== from
->name_
;
1010 gold_assert(same_name
|| this->has_alias());
1012 // If we are overriding an undef, remember the original binding.
1013 if (this->is_undefined())
1014 this->set_undef_binding(this->binding_
);
1016 this->source_
= from
->source_
;
1017 switch (from
->source_
)
1020 case IN_OUTPUT_DATA
:
1021 case IN_OUTPUT_SEGMENT
:
1022 this->u1_
= from
->u1_
;
1023 this->u2_
= from
->u2_
;
1035 // When overriding a versioned symbol with a special symbol, we
1036 // may be changing the version. This will happen if we see a
1037 // special symbol such as "_end" defined in a shared object with
1038 // one version (from a version script), but we want to define it
1039 // here with a different version (from a different version
1041 this->version_
= from
->version_
;
1043 this->type_
= from
->type_
;
1044 this->binding_
= from
->binding_
;
1045 this->override_visibility(from
->visibility_
);
1046 this->nonvis_
= from
->nonvis_
;
1048 // Special symbols are always considered to be regular symbols.
1049 this->in_reg_
= true;
1051 if (from
->needs_dynsym_entry_
)
1052 this->needs_dynsym_entry_
= true;
1053 if (from
->needs_dynsym_value_
)
1054 this->needs_dynsym_value_
= true;
1056 this->is_predefined_
= from
->is_predefined_
;
1058 // We shouldn't see these flags. If we do, we need to handle them
1060 gold_assert(!from
->is_forwarder_
);
1061 gold_assert(!from
->has_plt_offset());
1062 gold_assert(!from
->has_warning_
);
1063 gold_assert(!from
->is_copied_from_dynobj_
);
1064 gold_assert(!from
->is_forced_local_
);
1067 // Override a symbol with a special symbol.
1071 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
1073 this->override_base_with_special(from
);
1074 this->value_
= from
->value_
;
1075 this->symsize_
= from
->symsize_
;
1078 // Override TOSYM with the special symbol FROMSYM. This handles all
1079 // aliases of TOSYM.
1083 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
1084 const Sized_symbol
<size
>* fromsym
)
1086 tosym
->override_with_special(fromsym
);
1087 if (tosym
->has_alias())
1089 Symbol
* sym
= this->weak_aliases_
[tosym
];
1090 gold_assert(sym
!= NULL
);
1091 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
1094 ssym
->override_with_special(fromsym
);
1095 sym
= this->weak_aliases_
[ssym
];
1096 gold_assert(sym
!= NULL
);
1097 ssym
= this->get_sized_symbol
<size
>(sym
);
1099 while (ssym
!= tosym
);
1101 if (tosym
->binding() == elfcpp::STB_LOCAL
1102 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1103 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1104 && (tosym
->binding() == elfcpp::STB_GLOBAL
1105 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1106 || tosym
->binding() == elfcpp::STB_WEAK
)
1107 && !parameters
->options().relocatable()))
1108 this->force_local(tosym
);
1111 // Instantiate the templates we need. We could use the configure
1112 // script to restrict this to only the ones needed for implemented
1115 // We have to instantiate both big and little endian versions because
1116 // these are used by other templates that depends on size only.
1118 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1121 Symbol_table::resolve
<32, false>(
1122 Sized_symbol
<32>* to
,
1123 const elfcpp::Sym
<32, false>& sym
,
1124 unsigned int st_shndx
,
1126 unsigned int orig_st_shndx
,
1128 const char* version
,
1129 bool is_default_version
);
1133 Symbol_table::resolve
<32, true>(
1134 Sized_symbol
<32>* to
,
1135 const elfcpp::Sym
<32, true>& sym
,
1136 unsigned int st_shndx
,
1138 unsigned int orig_st_shndx
,
1140 const char* version
,
1141 bool is_default_version
);
1144 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1147 Symbol_table::resolve
<64, false>(
1148 Sized_symbol
<64>* to
,
1149 const elfcpp::Sym
<64, false>& sym
,
1150 unsigned int st_shndx
,
1152 unsigned int orig_st_shndx
,
1154 const char* version
,
1155 bool is_default_version
);
1159 Symbol_table::resolve
<64, true>(
1160 Sized_symbol
<64>* to
,
1161 const elfcpp::Sym
<64, true>& sym
,
1162 unsigned int st_shndx
,
1164 unsigned int orig_st_shndx
,
1166 const char* version
,
1167 bool is_default_version
);
1170 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1173 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1174 const Sized_symbol
<32>*);
1177 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1180 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1181 const Sized_symbol
<64>*);
1186 Sized_symbol
<32>::clone(const Sized_symbol
<32>*);
1190 Sized_symbol
<64>::clone(const Sized_symbol
<64>*);
1191 } // End namespace gold.