1 // resolve.cc -- symbol resolution for gold
3 // Copyright (C) 2006-2015 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 // Symbol methods used in this file.
36 // This symbol is being overridden by another symbol whose version is
37 // VERSION. Update the VERSION_ field accordingly.
40 Symbol::override_version(const char* version
)
44 // This is the case where this symbol is NAME/VERSION, and the
45 // version was not marked as hidden. That makes it the default
46 // version, so we create NAME/NULL. Later we see another symbol
47 // NAME/NULL, and that symbol is overriding this one. In this
48 // case, since NAME/VERSION is the default, we make NAME/NULL
49 // override NAME/VERSION as well. They are already the same
50 // Symbol structure. Setting the VERSION_ field to NULL ensures
51 // that it will be output with the correct, empty, version.
52 this->version_
= version
;
56 // This is the case where this symbol is NAME/VERSION_ONE, and
57 // now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is
58 // overriding NAME. If VERSION_ONE and VERSION_TWO are
59 // different, then this can only happen when VERSION_ONE is NULL
60 // and VERSION_TWO is not hidden.
61 gold_assert(this->version_
== version
|| this->version_
== NULL
);
62 this->version_
= version
;
66 // This symbol is being overidden by another symbol whose visibility
67 // is VISIBILITY. Updated the VISIBILITY_ field accordingly.
70 Symbol::override_visibility(elfcpp::STV visibility
)
72 // The rule for combining visibility is that we always choose the
73 // most constrained visibility. In order of increasing constraint,
74 // visibility goes PROTECTED, HIDDEN, INTERNAL. This is the reverse
75 // of the numeric values, so the effect is that we always want the
76 // smallest non-zero value.
77 if (visibility
!= elfcpp::STV_DEFAULT
)
79 if (this->visibility_
== elfcpp::STV_DEFAULT
)
80 this->visibility_
= visibility
;
81 else if (this->visibility_
> visibility
)
82 this->visibility_
= visibility
;
86 // Override the fields in Symbol.
88 template<int size
, bool big_endian
>
90 Symbol::override_base(const elfcpp::Sym
<size
, big_endian
>& sym
,
91 unsigned int st_shndx
, bool is_ordinary
,
92 Object
* object
, const char* version
)
94 gold_assert(this->source_
== FROM_OBJECT
);
95 this->u_
.from_object
.object
= object
;
96 this->override_version(version
);
97 this->u_
.from_object
.shndx
= st_shndx
;
98 this->is_ordinary_shndx_
= is_ordinary
;
99 // Don't override st_type from plugin placeholder symbols.
100 if (object
->pluginobj() == NULL
)
101 this->type_
= sym
.get_st_type();
102 this->binding_
= sym
.get_st_bind();
103 this->override_visibility(sym
.get_st_visibility());
104 this->nonvis_
= sym
.get_st_nonvis();
105 if (object
->is_dynamic())
106 this->in_dyn_
= true;
108 this->in_reg_
= true;
111 // Override the fields in Sized_symbol.
114 template<bool big_endian
>
116 Sized_symbol
<size
>::override(const elfcpp::Sym
<size
, big_endian
>& sym
,
117 unsigned st_shndx
, bool is_ordinary
,
118 Object
* object
, const char* version
)
120 this->override_base(sym
, st_shndx
, is_ordinary
, object
, version
);
121 this->value_
= sym
.get_st_value();
122 this->symsize_
= sym
.get_st_size();
125 // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version
126 // VERSION. This handles all aliases of TOSYM.
128 template<int size
, bool big_endian
>
130 Symbol_table::override(Sized_symbol
<size
>* tosym
,
131 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
132 unsigned int st_shndx
, bool is_ordinary
,
133 Object
* object
, const char* version
)
135 tosym
->override(fromsym
, st_shndx
, is_ordinary
, object
, version
);
136 if (tosym
->has_alias())
138 Symbol
* sym
= this->weak_aliases_
[tosym
];
139 gold_assert(sym
!= NULL
);
140 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
143 ssym
->override(fromsym
, st_shndx
, is_ordinary
, object
, version
);
144 sym
= this->weak_aliases_
[ssym
];
145 gold_assert(sym
!= NULL
);
146 ssym
= this->get_sized_symbol
<size
>(sym
);
148 while (ssym
!= tosym
);
152 // The resolve functions build a little code for each symbol.
153 // Bit 0: 0 for global, 1 for weak.
154 // Bit 1: 0 for regular object, 1 for shared object
155 // Bits 2-3: 0 for normal, 1 for undefined, 2 for common
156 // This gives us values from 0 to 11.
158 static const int global_or_weak_shift
= 0;
159 static const unsigned int global_flag
= 0 << global_or_weak_shift
;
160 static const unsigned int weak_flag
= 1 << global_or_weak_shift
;
162 static const int regular_or_dynamic_shift
= 1;
163 static const unsigned int regular_flag
= 0 << regular_or_dynamic_shift
;
164 static const unsigned int dynamic_flag
= 1 << regular_or_dynamic_shift
;
166 static const int def_undef_or_common_shift
= 2;
167 static const unsigned int def_flag
= 0 << def_undef_or_common_shift
;
168 static const unsigned int undef_flag
= 1 << def_undef_or_common_shift
;
169 static const unsigned int common_flag
= 2 << def_undef_or_common_shift
;
171 // This convenience function combines all the flags based on facts
175 symbol_to_bits(elfcpp::STB binding
, bool is_dynamic
,
176 unsigned int shndx
, bool is_ordinary
)
182 case elfcpp::STB_GLOBAL
:
183 case elfcpp::STB_GNU_UNIQUE
:
187 case elfcpp::STB_WEAK
:
191 case elfcpp::STB_LOCAL
:
192 // We should only see externally visible symbols in the symbol
194 gold_error(_("invalid STB_LOCAL symbol in external symbols"));
198 // Any target which wants to handle STB_LOOS, etc., needs to
199 // define a resolve method.
200 gold_error(_("unsupported symbol binding %d"), static_cast<int>(binding
));
205 bits
|= dynamic_flag
;
207 bits
|= regular_flag
;
211 case elfcpp::SHN_UNDEF
:
215 case elfcpp::SHN_COMMON
:
221 if (!is_ordinary
&& Symbol::is_common_shndx(shndx
))
231 // Resolve a symbol. This is called the second and subsequent times
232 // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
233 // section index for SYM, possibly adjusted for many sections.
234 // IS_ORDINARY is whether ST_SHNDX is a normal section index rather
235 // than a special code. ORIG_ST_SHNDX is the original section index,
236 // before any munging because of discarded sections, except that all
237 // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
238 // the version of SYM.
240 template<int size
, bool big_endian
>
242 Symbol_table::resolve(Sized_symbol
<size
>* to
,
243 const elfcpp::Sym
<size
, big_endian
>& sym
,
244 unsigned int st_shndx
, bool is_ordinary
,
245 unsigned int orig_st_shndx
,
246 Object
* object
, const char* version
)
248 // It's possible for a symbol to be defined in an object file
249 // using .symver to give it a version, and for there to also be
250 // a linker script giving that symbol the same version. We
251 // don't want to give a multiple-definition error for this
252 // harmless redefinition.
254 if (to
->source() == Symbol::FROM_OBJECT
255 && to
->object() == object
258 && to
->shndx(&to_is_ordinary
) == st_shndx
260 && to
->value() == sym
.get_st_value())
263 if (parameters
->target().has_resolve())
265 Sized_target
<size
, big_endian
>* sized_target
;
266 sized_target
= parameters
->sized_target
<size
, big_endian
>();
267 sized_target
->resolve(to
, sym
, object
, version
);
271 if (!object
->is_dynamic())
273 if (sym
.get_st_type() == elfcpp::STT_COMMON
274 && (is_ordinary
|| !Symbol::is_common_shndx(st_shndx
)))
276 gold_warning(_("STT_COMMON symbol '%s' in %s "
277 "is not in a common section"),
278 to
->demangled_name().c_str(),
279 to
->object()->name().c_str());
282 // Record that we've seen this symbol in a regular object.
285 else if (st_shndx
== elfcpp::SHN_UNDEF
286 && (to
->visibility() == elfcpp::STV_HIDDEN
287 || to
->visibility() == elfcpp::STV_INTERNAL
))
289 // The symbol is hidden, so a reference from a shared object
290 // cannot bind to it. We tried issuing a warning in this case,
291 // but that produces false positives when the symbol is
292 // actually resolved in a different shared object (PR 15574).
297 // Record that we've seen this symbol in a dynamic object.
301 // Record if we've seen this symbol in a real ELF object (i.e., the
302 // symbol is referenced from outside the world known to the plugin).
303 if (object
->pluginobj() == NULL
&& !object
->is_dynamic())
304 to
->set_in_real_elf();
306 // If we're processing replacement files, allow new symbols to override
307 // the placeholders from the plugin objects.
308 // Treat common symbols specially since it is possible that an ELF
309 // file increased the size of the alignment.
310 if (to
->source() == Symbol::FROM_OBJECT
)
312 Pluginobj
* obj
= to
->object()->pluginobj();
314 && parameters
->options().plugins()->in_replacement_phase())
316 bool adjust_common
= false;
317 typename Sized_symbol
<size
>::Size_type tosize
= 0;
318 typename Sized_symbol
<size
>::Value_type tovalue
= 0;
320 && !is_ordinary
&& Symbol::is_common_shndx(st_shndx
))
322 adjust_common
= true;
323 tosize
= to
->symsize();
324 tovalue
= to
->value();
326 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
329 if (tosize
> to
->symsize())
330 to
->set_symsize(tosize
);
331 if (tovalue
> to
->value())
332 to
->set_value(tovalue
);
338 // A new weak undefined reference, merging with an old weak
339 // reference, could be a One Definition Rule (ODR) violation --
340 // especially if the types or sizes of the references differ. We'll
341 // store such pairs and look them up later to make sure they
342 // actually refer to the same lines of code. We also check
343 // combinations of weak and strong, which might occur if one case is
344 // inline and the other is not. (Note: not all ODR violations can
345 // be found this way, and not everything this finds is an ODR
346 // violation. But it's helpful to warn about.)
347 if (parameters
->options().detect_odr_violations()
348 && (sym
.get_st_bind() == elfcpp::STB_WEAK
349 || to
->binding() == elfcpp::STB_WEAK
)
350 && orig_st_shndx
!= elfcpp::SHN_UNDEF
351 && to
->shndx(&to_is_ordinary
) != elfcpp::SHN_UNDEF
353 && sym
.get_st_size() != 0 // Ignore weird 0-sized symbols.
354 && to
->symsize() != 0
355 && (sym
.get_st_type() != to
->type()
356 || sym
.get_st_size() != to
->symsize())
357 // C does not have a concept of ODR, so we only need to do this
358 // on C++ symbols. These have (mangled) names starting with _Z.
359 && to
->name()[0] == '_' && to
->name()[1] == 'Z')
361 Symbol_location fromloc
362 = { object
, orig_st_shndx
, static_cast<off_t
>(sym
.get_st_value()) };
363 Symbol_location toloc
= { to
->object(), to
->shndx(&to_is_ordinary
),
364 static_cast<off_t
>(to
->value()) };
365 this->candidate_odr_violations_
[to
->name()].insert(fromloc
);
366 this->candidate_odr_violations_
[to
->name()].insert(toloc
);
369 // Plugins don't provide a symbol type, so adopt the existing type
370 // if the FROM symbol is from a plugin.
371 elfcpp::STT fromtype
= (object
->pluginobj() != NULL
373 : sym
.get_st_type());
374 unsigned int frombits
= symbol_to_bits(sym
.get_st_bind(),
375 object
->is_dynamic(),
376 st_shndx
, is_ordinary
);
378 bool adjust_common_sizes
;
380 typename Sized_symbol
<size
>::Size_type tosize
= to
->symsize();
381 if (Symbol_table::should_override(to
, frombits
, fromtype
, OBJECT
,
382 object
, &adjust_common_sizes
,
385 elfcpp::STB tobinding
= to
->binding();
386 typename Sized_symbol
<size
>::Value_type tovalue
= to
->value();
387 this->override(to
, sym
, st_shndx
, is_ordinary
, object
, version
);
388 if (adjust_common_sizes
)
390 if (tosize
> to
->symsize())
391 to
->set_symsize(tosize
);
392 if (tovalue
> to
->value())
393 to
->set_value(tovalue
);
397 // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
398 // Remember which kind of UNDEF it was for future reference.
399 to
->set_undef_binding(tobinding
);
404 if (adjust_common_sizes
)
406 if (sym
.get_st_size() > tosize
)
407 to
->set_symsize(sym
.get_st_size());
408 if (sym
.get_st_value() > to
->value())
409 to
->set_value(sym
.get_st_value());
413 // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
414 // Remember which kind of UNDEF it was.
415 to
->set_undef_binding(sym
.get_st_bind());
417 // The ELF ABI says that even for a reference to a symbol we
418 // merge the visibility.
419 to
->override_visibility(sym
.get_st_visibility());
422 if (adjust_common_sizes
&& parameters
->options().warn_common())
424 if (tosize
> sym
.get_st_size())
425 Symbol_table::report_resolve_problem(false,
426 _("common of '%s' overriding "
429 else if (tosize
< sym
.get_st_size())
430 Symbol_table::report_resolve_problem(false,
431 _("common of '%s' overidden by "
435 Symbol_table::report_resolve_problem(false,
436 _("multiple common of '%s'"),
441 // Handle the core of symbol resolution. This is called with the
442 // existing symbol, TO, and a bitflag describing the new symbol. This
443 // returns true if we should override the existing symbol with the new
444 // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
445 // true if we should set the symbol size to the maximum of the TO and
446 // FROM sizes. It handles error conditions.
449 Symbol_table::should_override(const Symbol
* to
, unsigned int frombits
,
450 elfcpp::STT fromtype
, Defined defined
,
451 Object
* object
, bool* adjust_common_sizes
,
454 *adjust_common_sizes
= false;
455 *adjust_dyndef
= false;
458 if (to
->source() == Symbol::IS_UNDEFINED
)
459 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_UNDEF
, true);
460 else if (to
->source() != Symbol::FROM_OBJECT
)
461 tobits
= symbol_to_bits(to
->binding(), false, elfcpp::SHN_ABS
, false);
465 unsigned int shndx
= to
->shndx(&is_ordinary
);
466 tobits
= symbol_to_bits(to
->binding(),
467 to
->object()->is_dynamic(),
472 if ((to
->type() == elfcpp::STT_TLS
) ^ (fromtype
== elfcpp::STT_TLS
)
473 && !to
->is_placeholder())
474 Symbol_table::report_resolve_problem(true,
475 _("symbol '%s' used as both __thread "
477 to
, defined
, object
);
479 // We use a giant switch table for symbol resolution. This code is
480 // unwieldy, but: 1) it is efficient; 2) we definitely handle all
481 // cases; 3) it is easy to change the handling of a particular case.
482 // The alternative would be a series of conditionals, but it is easy
483 // to get the ordering wrong. This could also be done as a table,
484 // but that is no easier to understand than this large switch
487 // These are the values generated by the bit codes.
490 DEF
= global_flag
| regular_flag
| def_flag
,
491 WEAK_DEF
= weak_flag
| regular_flag
| def_flag
,
492 DYN_DEF
= global_flag
| dynamic_flag
| def_flag
,
493 DYN_WEAK_DEF
= weak_flag
| dynamic_flag
| def_flag
,
494 UNDEF
= global_flag
| regular_flag
| undef_flag
,
495 WEAK_UNDEF
= weak_flag
| regular_flag
| undef_flag
,
496 DYN_UNDEF
= global_flag
| dynamic_flag
| undef_flag
,
497 DYN_WEAK_UNDEF
= weak_flag
| dynamic_flag
| undef_flag
,
498 COMMON
= global_flag
| regular_flag
| common_flag
,
499 WEAK_COMMON
= weak_flag
| regular_flag
| common_flag
,
500 DYN_COMMON
= global_flag
| dynamic_flag
| common_flag
,
501 DYN_WEAK_COMMON
= weak_flag
| dynamic_flag
| common_flag
504 switch (tobits
* 16 + frombits
)
507 // Two definitions of the same symbol.
509 // If either symbol is defined by an object included using
510 // --just-symbols, then don't warn. This is for compatibility
511 // with the GNU linker. FIXME: This is a hack.
512 if ((to
->source() == Symbol::FROM_OBJECT
&& to
->object()->just_symbols())
513 || (object
!= NULL
&& object
->just_symbols()))
516 if (!parameters
->options().muldefs())
517 Symbol_table::report_resolve_problem(true,
518 _("multiple definition of '%s'"),
519 to
, defined
, object
);
522 case WEAK_DEF
* 16 + DEF
:
523 // We've seen a weak definition, and now we see a strong
524 // definition. In the original SVR4 linker, this was treated as
525 // a multiple definition error. In the Solaris linker and the
526 // GNU linker, a weak definition followed by a regular
527 // definition causes the weak definition to be overridden. We
528 // are currently compatible with the GNU linker. In the future
529 // we should add a target specific option to change this.
533 case DYN_DEF
* 16 + DEF
:
534 case DYN_WEAK_DEF
* 16 + DEF
:
535 // We've seen a definition in a dynamic object, and now we see a
536 // definition in a regular object. The definition in the
537 // regular object overrides the definition in the dynamic
541 case UNDEF
* 16 + DEF
:
542 case WEAK_UNDEF
* 16 + DEF
:
543 case DYN_UNDEF
* 16 + DEF
:
544 case DYN_WEAK_UNDEF
* 16 + DEF
:
545 // We've seen an undefined reference, and now we see a
546 // definition. We use the definition.
549 case COMMON
* 16 + DEF
:
550 case WEAK_COMMON
* 16 + DEF
:
551 case DYN_COMMON
* 16 + DEF
:
552 case DYN_WEAK_COMMON
* 16 + DEF
:
553 // We've seen a common symbol and now we see a definition. The
554 // definition overrides.
555 if (parameters
->options().warn_common())
556 Symbol_table::report_resolve_problem(false,
557 _("definition of '%s' overriding "
559 to
, defined
, object
);
562 case DEF
* 16 + WEAK_DEF
:
563 case WEAK_DEF
* 16 + WEAK_DEF
:
564 // We've seen a definition and now we see a weak definition. We
565 // ignore the new weak definition.
568 case DYN_DEF
* 16 + WEAK_DEF
:
569 case DYN_WEAK_DEF
* 16 + WEAK_DEF
:
570 // We've seen a dynamic definition and now we see a regular weak
571 // definition. The regular weak definition overrides.
574 case UNDEF
* 16 + WEAK_DEF
:
575 case WEAK_UNDEF
* 16 + WEAK_DEF
:
576 case DYN_UNDEF
* 16 + WEAK_DEF
:
577 case DYN_WEAK_UNDEF
* 16 + WEAK_DEF
:
578 // A weak definition of a currently undefined symbol.
581 case COMMON
* 16 + WEAK_DEF
:
582 case WEAK_COMMON
* 16 + WEAK_DEF
:
583 // A weak definition does not override a common definition.
586 case DYN_COMMON
* 16 + WEAK_DEF
:
587 case DYN_WEAK_COMMON
* 16 + WEAK_DEF
:
588 // A weak definition does override a definition in a dynamic
590 if (parameters
->options().warn_common())
591 Symbol_table::report_resolve_problem(false,
592 _("definition of '%s' overriding "
593 "dynamic common definition"),
594 to
, defined
, object
);
597 case DEF
* 16 + DYN_DEF
:
598 case WEAK_DEF
* 16 + DYN_DEF
:
599 case DYN_DEF
* 16 + DYN_DEF
:
600 case DYN_WEAK_DEF
* 16 + DYN_DEF
:
601 // Ignore a dynamic definition if we already have a definition.
604 case UNDEF
* 16 + DYN_DEF
:
605 case DYN_UNDEF
* 16 + DYN_DEF
:
606 case DYN_WEAK_UNDEF
* 16 + DYN_DEF
:
607 // Use a dynamic definition if we have a reference.
610 case WEAK_UNDEF
* 16 + DYN_DEF
:
611 // When overriding a weak undef by a dynamic definition,
612 // we need to remember that the original undef was weak.
613 *adjust_dyndef
= true;
616 case COMMON
* 16 + DYN_DEF
:
617 case WEAK_COMMON
* 16 + DYN_DEF
:
618 case DYN_COMMON
* 16 + DYN_DEF
:
619 case DYN_WEAK_COMMON
* 16 + DYN_DEF
:
620 // Ignore a dynamic definition if we already have a common
624 case DEF
* 16 + DYN_WEAK_DEF
:
625 case WEAK_DEF
* 16 + DYN_WEAK_DEF
:
626 case DYN_DEF
* 16 + DYN_WEAK_DEF
:
627 case DYN_WEAK_DEF
* 16 + DYN_WEAK_DEF
:
628 // Ignore a weak dynamic definition if we already have a
632 case UNDEF
* 16 + DYN_WEAK_DEF
:
633 // When overriding an undef by a dynamic weak definition,
634 // we need to remember that the original undef was not weak.
635 *adjust_dyndef
= true;
638 case DYN_UNDEF
* 16 + DYN_WEAK_DEF
:
639 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
640 // Use a weak dynamic definition if we have a reference.
643 case WEAK_UNDEF
* 16 + DYN_WEAK_DEF
:
644 // When overriding a weak undef by a dynamic definition,
645 // we need to remember that the original undef was weak.
646 *adjust_dyndef
= true;
649 case COMMON
* 16 + DYN_WEAK_DEF
:
650 case WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
651 case DYN_COMMON
* 16 + DYN_WEAK_DEF
:
652 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_DEF
:
653 // Ignore a weak dynamic definition if we already have a common
657 case DEF
* 16 + UNDEF
:
658 case WEAK_DEF
* 16 + UNDEF
:
659 case UNDEF
* 16 + UNDEF
:
660 // A new undefined reference tells us nothing.
663 case DYN_DEF
* 16 + UNDEF
:
664 case DYN_WEAK_DEF
* 16 + UNDEF
:
665 // For a dynamic def, we need to remember which kind of undef we see.
666 *adjust_dyndef
= true;
669 case WEAK_UNDEF
* 16 + UNDEF
:
670 case DYN_UNDEF
* 16 + UNDEF
:
671 case DYN_WEAK_UNDEF
* 16 + UNDEF
:
672 // A strong undef overrides a dynamic or weak undef.
675 case COMMON
* 16 + UNDEF
:
676 case WEAK_COMMON
* 16 + UNDEF
:
677 case DYN_COMMON
* 16 + UNDEF
:
678 case DYN_WEAK_COMMON
* 16 + UNDEF
:
679 // A new undefined reference tells us nothing.
682 case DEF
* 16 + WEAK_UNDEF
:
683 case WEAK_DEF
* 16 + WEAK_UNDEF
:
684 case UNDEF
* 16 + WEAK_UNDEF
:
685 case WEAK_UNDEF
* 16 + WEAK_UNDEF
:
686 case DYN_UNDEF
* 16 + WEAK_UNDEF
:
687 case COMMON
* 16 + WEAK_UNDEF
:
688 case WEAK_COMMON
* 16 + WEAK_UNDEF
:
689 case DYN_COMMON
* 16 + WEAK_UNDEF
:
690 case DYN_WEAK_COMMON
* 16 + WEAK_UNDEF
:
691 // A new weak undefined reference tells us nothing unless the
692 // exisiting symbol is a dynamic weak reference.
695 case DYN_WEAK_UNDEF
* 16 + WEAK_UNDEF
:
696 // A new weak reference overrides an existing dynamic weak reference.
697 // This is necessary because a dynamic weak reference remembers
698 // the old binding, which may not be weak. If we keeps the existing
699 // dynamic weak reference, the weakness may be dropped in the output.
702 case DYN_DEF
* 16 + WEAK_UNDEF
:
703 case DYN_WEAK_DEF
* 16 + WEAK_UNDEF
:
704 // For a dynamic def, we need to remember which kind of undef we see.
705 *adjust_dyndef
= true;
708 case DEF
* 16 + DYN_UNDEF
:
709 case WEAK_DEF
* 16 + DYN_UNDEF
:
710 case DYN_DEF
* 16 + DYN_UNDEF
:
711 case DYN_WEAK_DEF
* 16 + DYN_UNDEF
:
712 case UNDEF
* 16 + DYN_UNDEF
:
713 case WEAK_UNDEF
* 16 + DYN_UNDEF
:
714 case DYN_UNDEF
* 16 + DYN_UNDEF
:
715 case DYN_WEAK_UNDEF
* 16 + DYN_UNDEF
:
716 case COMMON
* 16 + DYN_UNDEF
:
717 case WEAK_COMMON
* 16 + DYN_UNDEF
:
718 case DYN_COMMON
* 16 + DYN_UNDEF
:
719 case DYN_WEAK_COMMON
* 16 + DYN_UNDEF
:
720 // A new dynamic undefined reference tells us nothing.
723 case DEF
* 16 + DYN_WEAK_UNDEF
:
724 case WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
725 case DYN_DEF
* 16 + DYN_WEAK_UNDEF
:
726 case DYN_WEAK_DEF
* 16 + DYN_WEAK_UNDEF
:
727 case UNDEF
* 16 + DYN_WEAK_UNDEF
:
728 case WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
729 case DYN_UNDEF
* 16 + DYN_WEAK_UNDEF
:
730 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_UNDEF
:
731 case COMMON
* 16 + DYN_WEAK_UNDEF
:
732 case WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
733 case DYN_COMMON
* 16 + DYN_WEAK_UNDEF
:
734 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_UNDEF
:
735 // A new weak dynamic undefined reference tells us nothing.
738 case DEF
* 16 + COMMON
:
739 // A common symbol does not override a definition.
740 if (parameters
->options().warn_common())
741 Symbol_table::report_resolve_problem(false,
742 _("common '%s' overridden by "
743 "previous definition"),
744 to
, defined
, object
);
747 case WEAK_DEF
* 16 + COMMON
:
748 case DYN_DEF
* 16 + COMMON
:
749 case DYN_WEAK_DEF
* 16 + COMMON
:
750 // A common symbol does override a weak definition or a dynamic
754 case UNDEF
* 16 + COMMON
:
755 case WEAK_UNDEF
* 16 + COMMON
:
756 case DYN_UNDEF
* 16 + COMMON
:
757 case DYN_WEAK_UNDEF
* 16 + COMMON
:
758 // A common symbol is a definition for a reference.
761 case COMMON
* 16 + COMMON
:
762 // Set the size to the maximum.
763 *adjust_common_sizes
= true;
766 case WEAK_COMMON
* 16 + COMMON
:
767 // I'm not sure just what a weak common symbol means, but
768 // presumably it can be overridden by a regular common symbol.
771 case DYN_COMMON
* 16 + COMMON
:
772 case DYN_WEAK_COMMON
* 16 + COMMON
:
773 // Use the real common symbol, but adjust the size if necessary.
774 *adjust_common_sizes
= true;
777 case DEF
* 16 + WEAK_COMMON
:
778 case WEAK_DEF
* 16 + WEAK_COMMON
:
779 case DYN_DEF
* 16 + WEAK_COMMON
:
780 case DYN_WEAK_DEF
* 16 + WEAK_COMMON
:
781 // Whatever a weak common symbol is, it won't override a
785 case UNDEF
* 16 + WEAK_COMMON
:
786 case WEAK_UNDEF
* 16 + WEAK_COMMON
:
787 case DYN_UNDEF
* 16 + WEAK_COMMON
:
788 case DYN_WEAK_UNDEF
* 16 + WEAK_COMMON
:
789 // A weak common symbol is better than an undefined symbol.
792 case COMMON
* 16 + WEAK_COMMON
:
793 case WEAK_COMMON
* 16 + WEAK_COMMON
:
794 case DYN_COMMON
* 16 + WEAK_COMMON
:
795 case DYN_WEAK_COMMON
* 16 + WEAK_COMMON
:
796 // Ignore a weak common symbol in the presence of a real common
800 case DEF
* 16 + DYN_COMMON
:
801 case WEAK_DEF
* 16 + DYN_COMMON
:
802 case DYN_DEF
* 16 + DYN_COMMON
:
803 case DYN_WEAK_DEF
* 16 + DYN_COMMON
:
804 // Ignore a dynamic common symbol in the presence of a
808 case UNDEF
* 16 + DYN_COMMON
:
809 case WEAK_UNDEF
* 16 + DYN_COMMON
:
810 case DYN_UNDEF
* 16 + DYN_COMMON
:
811 case DYN_WEAK_UNDEF
* 16 + DYN_COMMON
:
812 // A dynamic common symbol is a definition of sorts.
815 case COMMON
* 16 + DYN_COMMON
:
816 case WEAK_COMMON
* 16 + DYN_COMMON
:
817 case DYN_COMMON
* 16 + DYN_COMMON
:
818 case DYN_WEAK_COMMON
* 16 + DYN_COMMON
:
819 // Set the size to the maximum.
820 *adjust_common_sizes
= true;
823 case DEF
* 16 + DYN_WEAK_COMMON
:
824 case WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
825 case DYN_DEF
* 16 + DYN_WEAK_COMMON
:
826 case DYN_WEAK_DEF
* 16 + DYN_WEAK_COMMON
:
827 // A common symbol is ignored in the face of a definition.
830 case UNDEF
* 16 + DYN_WEAK_COMMON
:
831 case WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
832 case DYN_UNDEF
* 16 + DYN_WEAK_COMMON
:
833 case DYN_WEAK_UNDEF
* 16 + DYN_WEAK_COMMON
:
834 // I guess a weak common symbol is better than a definition.
837 case COMMON
* 16 + DYN_WEAK_COMMON
:
838 case WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
839 case DYN_COMMON
* 16 + DYN_WEAK_COMMON
:
840 case DYN_WEAK_COMMON
* 16 + DYN_WEAK_COMMON
:
841 // Set the size to the maximum.
842 *adjust_common_sizes
= true;
850 // Issue an error or warning due to symbol resolution. IS_ERROR
851 // indicates an error rather than a warning. MSG is the error
852 // message; it is expected to have a %s for the symbol name. TO is
853 // the existing symbol. DEFINED/OBJECT is where the new symbol was
856 // FIXME: We should have better location information here. When the
857 // symbol is defined, we should be able to pull the location from the
858 // debug info if there is any.
861 Symbol_table::report_resolve_problem(bool is_error
, const char* msg
,
862 const Symbol
* to
, Defined defined
,
865 std::string
demangled(to
->demangled_name());
866 size_t len
= strlen(msg
) + demangled
.length() + 10;
867 char* buf
= new char[len
];
868 snprintf(buf
, len
, msg
, demangled
.c_str());
874 objname
= object
->name().c_str();
877 objname
= _("COPY reloc");
881 objname
= _("command line");
884 objname
= _("linker script");
887 case INCREMENTAL_BASE
:
888 objname
= _("linker defined");
895 gold_error("%s: %s", objname
, buf
);
897 gold_warning("%s: %s", objname
, buf
);
901 if (to
->source() == Symbol::FROM_OBJECT
)
902 objname
= to
->object()->name().c_str();
904 objname
= _("command line");
905 gold_info("%s: %s: previous definition here", program_name
, objname
);
908 // A special case of should_override which is only called for a strong
909 // defined symbol from a regular object file. This is used when
910 // defining special symbols.
913 Symbol_table::should_override_with_special(const Symbol
* to
,
914 elfcpp::STT fromtype
,
917 bool adjust_common_sizes
;
919 unsigned int frombits
= global_flag
| regular_flag
| def_flag
;
920 bool ret
= Symbol_table::should_override(to
, frombits
, fromtype
, defined
,
921 NULL
, &adjust_common_sizes
,
923 gold_assert(!adjust_common_sizes
&& !adjust_dyn_def
);
927 // Override symbol base with a special symbol.
930 Symbol::override_base_with_special(const Symbol
* from
)
932 bool same_name
= this->name_
== from
->name_
;
933 gold_assert(same_name
|| this->has_alias());
935 // If we are overriding an undef, remember the original binding.
936 if (this->is_undefined())
937 this->set_undef_binding(this->binding_
);
939 this->source_
= from
->source_
;
940 switch (from
->source_
)
943 this->u_
.from_object
= from
->u_
.from_object
;
946 this->u_
.in_output_data
= from
->u_
.in_output_data
;
948 case IN_OUTPUT_SEGMENT
:
949 this->u_
.in_output_segment
= from
->u_
.in_output_segment
;
961 // When overriding a versioned symbol with a special symbol, we
962 // may be changing the version. This will happen if we see a
963 // special symbol such as "_end" defined in a shared object with
964 // one version (from a version script), but we want to define it
965 // here with a different version (from a different version
967 this->version_
= from
->version_
;
969 this->type_
= from
->type_
;
970 this->binding_
= from
->binding_
;
971 this->override_visibility(from
->visibility_
);
972 this->nonvis_
= from
->nonvis_
;
974 // Special symbols are always considered to be regular symbols.
975 this->in_reg_
= true;
977 if (from
->needs_dynsym_entry_
)
978 this->needs_dynsym_entry_
= true;
979 if (from
->needs_dynsym_value_
)
980 this->needs_dynsym_value_
= true;
982 this->is_predefined_
= from
->is_predefined_
;
984 // We shouldn't see these flags. If we do, we need to handle them
986 gold_assert(!from
->is_forwarder_
);
987 gold_assert(!from
->has_plt_offset());
988 gold_assert(!from
->has_warning_
);
989 gold_assert(!from
->is_copied_from_dynobj_
);
990 gold_assert(!from
->is_forced_local_
);
993 // Override a symbol with a special symbol.
997 Sized_symbol
<size
>::override_with_special(const Sized_symbol
<size
>* from
)
999 this->override_base_with_special(from
);
1000 this->value_
= from
->value_
;
1001 this->symsize_
= from
->symsize_
;
1004 // Override TOSYM with the special symbol FROMSYM. This handles all
1005 // aliases of TOSYM.
1009 Symbol_table::override_with_special(Sized_symbol
<size
>* tosym
,
1010 const Sized_symbol
<size
>* fromsym
)
1012 tosym
->override_with_special(fromsym
);
1013 if (tosym
->has_alias())
1015 Symbol
* sym
= this->weak_aliases_
[tosym
];
1016 gold_assert(sym
!= NULL
);
1017 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
1020 ssym
->override_with_special(fromsym
);
1021 sym
= this->weak_aliases_
[ssym
];
1022 gold_assert(sym
!= NULL
);
1023 ssym
= this->get_sized_symbol
<size
>(sym
);
1025 while (ssym
!= tosym
);
1027 if (tosym
->binding() == elfcpp::STB_LOCAL
1028 || ((tosym
->visibility() == elfcpp::STV_HIDDEN
1029 || tosym
->visibility() == elfcpp::STV_INTERNAL
)
1030 && (tosym
->binding() == elfcpp::STB_GLOBAL
1031 || tosym
->binding() == elfcpp::STB_GNU_UNIQUE
1032 || tosym
->binding() == elfcpp::STB_WEAK
)
1033 && !parameters
->options().relocatable()))
1034 this->force_local(tosym
);
1037 // Instantiate the templates we need. We could use the configure
1038 // script to restrict this to only the ones needed for implemented
1041 // We have to instantiate both big and little endian versions because
1042 // these are used by other templates that depends on size only.
1044 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1047 Symbol_table::resolve
<32, false>(
1048 Sized_symbol
<32>* to
,
1049 const elfcpp::Sym
<32, false>& sym
,
1050 unsigned int st_shndx
,
1052 unsigned int orig_st_shndx
,
1054 const char* version
);
1058 Symbol_table::resolve
<32, true>(
1059 Sized_symbol
<32>* to
,
1060 const elfcpp::Sym
<32, true>& sym
,
1061 unsigned int st_shndx
,
1063 unsigned int orig_st_shndx
,
1065 const char* version
);
1068 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1071 Symbol_table::resolve
<64, false>(
1072 Sized_symbol
<64>* to
,
1073 const elfcpp::Sym
<64, false>& sym
,
1074 unsigned int st_shndx
,
1076 unsigned int orig_st_shndx
,
1078 const char* version
);
1082 Symbol_table::resolve
<64, true>(
1083 Sized_symbol
<64>* to
,
1084 const elfcpp::Sym
<64, true>& sym
,
1085 unsigned int st_shndx
,
1087 unsigned int orig_st_shndx
,
1089 const char* version
);
1092 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1095 Symbol_table::override_with_special
<32>(Sized_symbol
<32>*,
1096 const Sized_symbol
<32>*);
1099 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1102 Symbol_table::override_with_special
<64>(Sized_symbol
<64>*,
1103 const Sized_symbol
<64>*);
1106 } // End namespace gold.