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14bfc3f5 ILT |
1 | // resolve.cc -- symbol resolution for gold |
2 | ||
0602e05a | 3 | // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
6cb15b7f ILT |
4 | // Written by Ian Lance Taylor <iant@google.com>. |
5 | ||
6 | // This file is part of gold. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. | |
22 | ||
14bfc3f5 ILT |
23 | #include "gold.h" |
24 | ||
25 | #include "elfcpp.h" | |
26 | #include "target.h" | |
27 | #include "object.h" | |
28 | #include "symtab.h" | |
89fc3421 | 29 | #include "plugin.h" |
14bfc3f5 ILT |
30 | |
31 | namespace gold | |
32 | { | |
33 | ||
1564db8d ILT |
34 | // Symbol methods used in this file. |
35 | ||
75517b77 ILT |
36 | // This symbol is being overridden by another symbol whose version is |
37 | // VERSION. Update the VERSION_ field accordingly. | |
38 | ||
39 | inline void | |
40 | Symbol::override_version(const char* version) | |
41 | { | |
42 | if (version == NULL) | |
43 | { | |
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; | |
53 | } | |
54 | else | |
55 | { | |
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; | |
63 | } | |
64 | } | |
65 | ||
0602e05a ILT |
66 | // This symbol is being overidden by another symbol whose visibility |
67 | // is VISIBILITY. Updated the VISIBILITY_ field accordingly. | |
68 | ||
69 | inline void | |
70 | Symbol::override_visibility(elfcpp::STV visibility) | |
71 | { | |
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) | |
78 | { | |
79 | if (this->visibility_ == elfcpp::STV_DEFAULT) | |
80 | this->visibility_ = visibility; | |
81 | else if (this->visibility_ > visibility) | |
82 | this->visibility_ = visibility; | |
83 | } | |
84 | } | |
85 | ||
1564db8d ILT |
86 | // Override the fields in Symbol. |
87 | ||
88 | template<int size, bool big_endian> | |
89 | void | |
90 | Symbol::override_base(const elfcpp::Sym<size, big_endian>& sym, | |
d491d34e | 91 | unsigned int st_shndx, bool is_ordinary, |
14b31740 | 92 | Object* object, const char* version) |
1564db8d | 93 | { |
a3ad94ed | 94 | gold_assert(this->source_ == FROM_OBJECT); |
ead1e424 | 95 | this->u_.from_object.object = object; |
75517b77 | 96 | this->override_version(version); |
d491d34e ILT |
97 | this->u_.from_object.shndx = st_shndx; |
98 | this->is_ordinary_shndx_ = is_ordinary; | |
1564db8d ILT |
99 | this->type_ = sym.get_st_type(); |
100 | this->binding_ = sym.get_st_bind(); | |
0602e05a | 101 | this->override_visibility(sym.get_st_visibility()); |
ead1e424 | 102 | this->nonvis_ = sym.get_st_nonvis(); |
0d4f1889 ILT |
103 | if (object->is_dynamic()) |
104 | this->in_dyn_ = true; | |
105 | else | |
106 | this->in_reg_ = true; | |
1564db8d ILT |
107 | } |
108 | ||
109 | // Override the fields in Sized_symbol. | |
110 | ||
111 | template<int size> | |
112 | template<bool big_endian> | |
113 | void | |
114 | Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym, | |
d491d34e | 115 | unsigned st_shndx, bool is_ordinary, |
14b31740 | 116 | Object* object, const char* version) |
1564db8d | 117 | { |
d491d34e | 118 | this->override_base(sym, st_shndx, is_ordinary, object, version); |
1564db8d | 119 | this->value_ = sym.get_st_value(); |
ead1e424 | 120 | this->symsize_ = sym.get_st_size(); |
1564db8d ILT |
121 | } |
122 | ||
aeddab66 ILT |
123 | // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version |
124 | // VERSION. This handles all aliases of TOSYM. | |
125 | ||
126 | template<int size, bool big_endian> | |
127 | void | |
128 | Symbol_table::override(Sized_symbol<size>* tosym, | |
129 | const elfcpp::Sym<size, big_endian>& fromsym, | |
d491d34e | 130 | unsigned int st_shndx, bool is_ordinary, |
aeddab66 ILT |
131 | Object* object, const char* version) |
132 | { | |
d491d34e | 133 | tosym->override(fromsym, st_shndx, is_ordinary, object, version); |
aeddab66 ILT |
134 | if (tosym->has_alias()) |
135 | { | |
136 | Symbol* sym = this->weak_aliases_[tosym]; | |
137 | gold_assert(sym != NULL); | |
7d1a9ebb | 138 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
139 | do |
140 | { | |
d491d34e | 141 | ssym->override(fromsym, st_shndx, is_ordinary, object, version); |
aeddab66 ILT |
142 | sym = this->weak_aliases_[ssym]; |
143 | gold_assert(sym != NULL); | |
7d1a9ebb | 144 | ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
145 | } |
146 | while (ssym != tosym); | |
147 | } | |
148 | } | |
149 | ||
86f2e683 ILT |
150 | // The resolve functions build a little code for each symbol. |
151 | // Bit 0: 0 for global, 1 for weak. | |
152 | // Bit 1: 0 for regular object, 1 for shared object | |
153 | // Bits 2-3: 0 for normal, 1 for undefined, 2 for common | |
154 | // This gives us values from 0 to 11. | |
155 | ||
156 | static const int global_or_weak_shift = 0; | |
157 | static const unsigned int global_flag = 0 << global_or_weak_shift; | |
158 | static const unsigned int weak_flag = 1 << global_or_weak_shift; | |
159 | ||
160 | static const int regular_or_dynamic_shift = 1; | |
161 | static const unsigned int regular_flag = 0 << regular_or_dynamic_shift; | |
162 | static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift; | |
163 | ||
164 | static const int def_undef_or_common_shift = 2; | |
165 | static const unsigned int def_flag = 0 << def_undef_or_common_shift; | |
166 | static const unsigned int undef_flag = 1 << def_undef_or_common_shift; | |
167 | static const unsigned int common_flag = 2 << def_undef_or_common_shift; | |
168 | ||
70e654ba ILT |
169 | // This convenience function combines all the flags based on facts |
170 | // about the symbol. | |
171 | ||
172 | static unsigned int | |
173 | symbol_to_bits(elfcpp::STB binding, bool is_dynamic, | |
d491d34e | 174 | unsigned int shndx, bool is_ordinary, elfcpp::STT type) |
70e654ba ILT |
175 | { |
176 | unsigned int bits; | |
177 | ||
178 | switch (binding) | |
179 | { | |
180 | case elfcpp::STB_GLOBAL: | |
181 | bits = global_flag; | |
182 | break; | |
183 | ||
184 | case elfcpp::STB_WEAK: | |
185 | bits = weak_flag; | |
186 | break; | |
187 | ||
188 | case elfcpp::STB_LOCAL: | |
189 | // We should only see externally visible symbols in the symbol | |
190 | // table. | |
191 | gold_error(_("invalid STB_LOCAL symbol in external symbols")); | |
192 | bits = global_flag; | |
193 | ||
194 | default: | |
195 | // Any target which wants to handle STB_LOOS, etc., needs to | |
196 | // define a resolve method. | |
197 | gold_error(_("unsupported symbol binding")); | |
198 | bits = global_flag; | |
199 | } | |
200 | ||
201 | if (is_dynamic) | |
202 | bits |= dynamic_flag; | |
203 | else | |
204 | bits |= regular_flag; | |
205 | ||
206 | switch (shndx) | |
207 | { | |
208 | case elfcpp::SHN_UNDEF: | |
209 | bits |= undef_flag; | |
210 | break; | |
211 | ||
212 | case elfcpp::SHN_COMMON: | |
d491d34e ILT |
213 | if (!is_ordinary) |
214 | bits |= common_flag; | |
70e654ba ILT |
215 | break; |
216 | ||
217 | default: | |
218 | if (type == elfcpp::STT_COMMON) | |
219 | bits |= common_flag; | |
8a5e3e08 ILT |
220 | else if (!is_ordinary && Symbol::is_common_shndx(shndx)) |
221 | bits |= common_flag; | |
70e654ba ILT |
222 | else |
223 | bits |= def_flag; | |
224 | break; | |
225 | } | |
226 | ||
227 | return bits; | |
228 | } | |
229 | ||
14bfc3f5 | 230 | // Resolve a symbol. This is called the second and subsequent times |
d491d34e ILT |
231 | // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the |
232 | // section index for SYM, possibly adjusted for many sections. | |
233 | // IS_ORDINARY is whether ST_SHNDX is a normal section index rather | |
234 | // than a special code. ORIG_ST_SHNDX is the original section index, | |
235 | // before any munging because of discarded sections, except that all | |
95d14cd3 | 236 | // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is |
d491d34e | 237 | // the version of SYM. |
14bfc3f5 ILT |
238 | |
239 | template<int size, bool big_endian> | |
240 | void | |
1564db8d | 241 | Symbol_table::resolve(Sized_symbol<size>* to, |
14bfc3f5 | 242 | const elfcpp::Sym<size, big_endian>& sym, |
d491d34e ILT |
243 | unsigned int st_shndx, bool is_ordinary, |
244 | unsigned int orig_st_shndx, | |
14b31740 | 245 | Object* object, const char* version) |
14bfc3f5 | 246 | { |
029ba973 | 247 | if (parameters->target().has_resolve()) |
14bfc3f5 | 248 | { |
274e99f9 | 249 | Sized_target<size, big_endian>* sized_target; |
029ba973 | 250 | sized_target = parameters->sized_target<size, big_endian>(); |
14b31740 | 251 | sized_target->resolve(to, sym, object, version); |
14bfc3f5 ILT |
252 | return; |
253 | } | |
254 | ||
86f2e683 ILT |
255 | if (!object->is_dynamic()) |
256 | { | |
257 | // Record that we've seen this symbol in a regular object. | |
258 | to->set_in_reg(); | |
259 | } | |
2da73f13 CC |
260 | else if (st_shndx == elfcpp::SHN_UNDEF |
261 | && (to->visibility() == elfcpp::STV_HIDDEN | |
262 | || to->visibility() == elfcpp::STV_INTERNAL)) | |
645afe0c CC |
263 | { |
264 | // A dynamic object cannot reference a hidden or internal symbol | |
265 | // defined in another object. | |
266 | gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"), | |
267 | (to->visibility() == elfcpp::STV_HIDDEN | |
268 | ? "hidden" | |
269 | : "internal"), | |
270 | to->demangled_name().c_str(), | |
271 | to->object()->name().c_str(), | |
272 | object->name().c_str()); | |
273 | return; | |
274 | } | |
86f2e683 ILT |
275 | else |
276 | { | |
277 | // Record that we've seen this symbol in a dynamic object. | |
278 | to->set_in_dyn(); | |
279 | } | |
14bfc3f5 | 280 | |
89fc3421 CC |
281 | // Record if we've seen this symbol in a real ELF object (i.e., the |
282 | // symbol is referenced from outside the world known to the plugin). | |
283 | if (object->pluginobj() == NULL) | |
284 | to->set_in_real_elf(); | |
285 | ||
286 | // If we're processing replacement files, allow new symbols to override | |
287 | // the placeholders from the plugin objects. | |
288 | if (to->source() == Symbol::FROM_OBJECT) | |
289 | { | |
290 | Pluginobj* obj = to->object()->pluginobj(); | |
291 | if (obj != NULL | |
292 | && parameters->options().plugins()->in_replacement_phase()) | |
293 | { | |
294 | this->override(to, sym, st_shndx, is_ordinary, object, version); | |
295 | return; | |
296 | } | |
297 | } | |
298 | ||
70e654ba ILT |
299 | unsigned int frombits = symbol_to_bits(sym.get_st_bind(), |
300 | object->is_dynamic(), | |
d491d34e | 301 | st_shndx, is_ordinary, |
70e654ba | 302 | sym.get_st_type()); |
14bfc3f5 | 303 | |
86f2e683 | 304 | bool adjust_common_sizes; |
d20222a1 ILT |
305 | if (Symbol_table::should_override(to, frombits, object, |
306 | &adjust_common_sizes)) | |
86f2e683 ILT |
307 | { |
308 | typename Sized_symbol<size>::Size_type tosize = to->symsize(); | |
309 | ||
d491d34e | 310 | this->override(to, sym, st_shndx, is_ordinary, object, version); |
86f2e683 ILT |
311 | |
312 | if (adjust_common_sizes && tosize > to->symsize()) | |
313 | to->set_symsize(tosize); | |
314 | } | |
315 | else | |
316 | { | |
317 | if (adjust_common_sizes && sym.get_st_size() > to->symsize()) | |
318 | to->set_symsize(sym.get_st_size()); | |
0602e05a ILT |
319 | // The ELF ABI says that even for a reference to a symbol we |
320 | // merge the visibility. | |
321 | to->override_visibility(sym.get_st_visibility()); | |
86f2e683 | 322 | } |
70e654ba ILT |
323 | |
324 | // A new weak undefined reference, merging with an old weak | |
325 | // reference, could be a One Definition Rule (ODR) violation -- | |
326 | // especially if the types or sizes of the references differ. We'll | |
327 | // store such pairs and look them up later to make sure they | |
328 | // actually refer to the same lines of code. (Note: not all ODR | |
329 | // violations can be found this way, and not everything this finds | |
330 | // is an ODR violation. But it's helpful to warn about.) | |
d491d34e | 331 | bool to_is_ordinary; |
8851ecca | 332 | if (parameters->options().detect_odr_violations() |
d491d34e | 333 | && sym.get_st_bind() == elfcpp::STB_WEAK |
70e654ba | 334 | && to->binding() == elfcpp::STB_WEAK |
d491d34e ILT |
335 | && orig_st_shndx != elfcpp::SHN_UNDEF |
336 | && to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF | |
337 | && to_is_ordinary | |
338 | && sym.get_st_size() != 0 // Ignore weird 0-sized symbols. | |
70e654ba | 339 | && to->symsize() != 0 |
d491d34e ILT |
340 | && (sym.get_st_type() != to->type() |
341 | || sym.get_st_size() != to->symsize()) | |
70e654ba ILT |
342 | // C does not have a concept of ODR, so we only need to do this |
343 | // on C++ symbols. These have (mangled) names starting with _Z. | |
344 | && to->name()[0] == '_' && to->name()[1] == 'Z') | |
345 | { | |
a2b1aa12 | 346 | Symbol_location fromloc |
d491d34e ILT |
347 | = { object, orig_st_shndx, sym.get_st_value() }; |
348 | Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), | |
349 | to->value() }; | |
a2b1aa12 ILT |
350 | this->candidate_odr_violations_[to->name()].insert(fromloc); |
351 | this->candidate_odr_violations_[to->name()].insert(toloc); | |
70e654ba | 352 | } |
86f2e683 ILT |
353 | } |
354 | ||
355 | // Handle the core of symbol resolution. This is called with the | |
356 | // existing symbol, TO, and a bitflag describing the new symbol. This | |
357 | // returns true if we should override the existing symbol with the new | |
358 | // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to | |
359 | // true if we should set the symbol size to the maximum of the TO and | |
360 | // FROM sizes. It handles error conditions. | |
361 | ||
362 | bool | |
363 | Symbol_table::should_override(const Symbol* to, unsigned int frombits, | |
d20222a1 | 364 | Object* object, bool* adjust_common_sizes) |
86f2e683 ILT |
365 | { |
366 | *adjust_common_sizes = false; | |
367 | ||
e5756efb | 368 | unsigned int tobits; |
f3e9c5c5 ILT |
369 | if (to->source() == Symbol::IS_UNDEFINED) |
370 | tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true, | |
371 | to->type()); | |
372 | else if (to->source() != Symbol::FROM_OBJECT) | |
d491d34e | 373 | tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false, |
e5756efb ILT |
374 | to->type()); |
375 | else | |
d491d34e ILT |
376 | { |
377 | bool is_ordinary; | |
378 | unsigned int shndx = to->shndx(&is_ordinary); | |
379 | tobits = symbol_to_bits(to->binding(), | |
380 | to->object()->is_dynamic(), | |
381 | shndx, | |
382 | is_ordinary, | |
383 | to->type()); | |
384 | } | |
14bfc3f5 | 385 | |
1564db8d ILT |
386 | // FIXME: Warn if either but not both of TO and SYM are STT_TLS. |
387 | ||
14bfc3f5 ILT |
388 | // We use a giant switch table for symbol resolution. This code is |
389 | // unwieldy, but: 1) it is efficient; 2) we definitely handle all | |
390 | // cases; 3) it is easy to change the handling of a particular case. | |
391 | // The alternative would be a series of conditionals, but it is easy | |
392 | // to get the ordering wrong. This could also be done as a table, | |
393 | // but that is no easier to understand than this large switch | |
394 | // statement. | |
395 | ||
86f2e683 ILT |
396 | // These are the values generated by the bit codes. |
397 | enum | |
398 | { | |
399 | DEF = global_flag | regular_flag | def_flag, | |
400 | WEAK_DEF = weak_flag | regular_flag | def_flag, | |
401 | DYN_DEF = global_flag | dynamic_flag | def_flag, | |
402 | DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag, | |
403 | UNDEF = global_flag | regular_flag | undef_flag, | |
404 | WEAK_UNDEF = weak_flag | regular_flag | undef_flag, | |
405 | DYN_UNDEF = global_flag | dynamic_flag | undef_flag, | |
406 | DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag, | |
407 | COMMON = global_flag | regular_flag | common_flag, | |
408 | WEAK_COMMON = weak_flag | regular_flag | common_flag, | |
409 | DYN_COMMON = global_flag | dynamic_flag | common_flag, | |
410 | DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag | |
411 | }; | |
412 | ||
14bfc3f5 ILT |
413 | switch (tobits * 16 + frombits) |
414 | { | |
415 | case DEF * 16 + DEF: | |
12e14209 | 416 | // Two definitions of the same symbol. |
878405a8 ILT |
417 | |
418 | // If either symbol is defined by an object included using | |
419 | // --just-symbols, then don't warn. This is for compatibility | |
420 | // with the GNU linker. FIXME: This is a hack. | |
421 | if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols()) | |
422 | || object->just_symbols()) | |
423 | return false; | |
424 | ||
d20222a1 ILT |
425 | // FIXME: Do a better job of reporting locations. |
426 | gold_error(_("%s: multiple definition of %s"), | |
427 | object != NULL ? object->name().c_str() : _("command line"), | |
a2b1aa12 | 428 | to->demangled_name().c_str()); |
d20222a1 ILT |
429 | gold_error(_("%s: previous definition here"), |
430 | (to->source() == Symbol::FROM_OBJECT | |
431 | ? to->object()->name().c_str() | |
432 | : _("command line"))); | |
86f2e683 | 433 | return false; |
14bfc3f5 ILT |
434 | |
435 | case WEAK_DEF * 16 + DEF: | |
1564db8d ILT |
436 | // We've seen a weak definition, and now we see a strong |
437 | // definition. In the original SVR4 linker, this was treated as | |
438 | // a multiple definition error. In the Solaris linker and the | |
439 | // GNU linker, a weak definition followed by a regular | |
440 | // definition causes the weak definition to be overridden. We | |
441 | // are currently compatible with the GNU linker. In the future | |
442 | // we should add a target specific option to change this. | |
443 | // FIXME. | |
86f2e683 | 444 | return true; |
14bfc3f5 ILT |
445 | |
446 | case DYN_DEF * 16 + DEF: | |
447 | case DYN_WEAK_DEF * 16 + DEF: | |
1564db8d ILT |
448 | // We've seen a definition in a dynamic object, and now we see a |
449 | // definition in a regular object. The definition in the | |
450 | // regular object overrides the definition in the dynamic | |
451 | // object. | |
86f2e683 | 452 | return true; |
1564db8d | 453 | |
14bfc3f5 ILT |
454 | case UNDEF * 16 + DEF: |
455 | case WEAK_UNDEF * 16 + DEF: | |
456 | case DYN_UNDEF * 16 + DEF: | |
457 | case DYN_WEAK_UNDEF * 16 + DEF: | |
1564db8d ILT |
458 | // We've seen an undefined reference, and now we see a |
459 | // definition. We use the definition. | |
86f2e683 | 460 | return true; |
1564db8d | 461 | |
14bfc3f5 ILT |
462 | case COMMON * 16 + DEF: |
463 | case WEAK_COMMON * 16 + DEF: | |
464 | case DYN_COMMON * 16 + DEF: | |
465 | case DYN_WEAK_COMMON * 16 + DEF: | |
1564db8d | 466 | // We've seen a common symbol and now we see a definition. The |
14b31740 | 467 | // definition overrides. FIXME: We should optionally issue, version a |
1564db8d | 468 | // warning. |
86f2e683 | 469 | return true; |
14bfc3f5 ILT |
470 | |
471 | case DEF * 16 + WEAK_DEF: | |
472 | case WEAK_DEF * 16 + WEAK_DEF: | |
1564db8d ILT |
473 | // We've seen a definition and now we see a weak definition. We |
474 | // ignore the new weak definition. | |
86f2e683 | 475 | return false; |
1564db8d | 476 | |
14bfc3f5 ILT |
477 | case DYN_DEF * 16 + WEAK_DEF: |
478 | case DYN_WEAK_DEF * 16 + WEAK_DEF: | |
1564db8d ILT |
479 | // We've seen a dynamic definition and now we see a regular weak |
480 | // definition. The regular weak definition overrides. | |
86f2e683 | 481 | return true; |
1564db8d | 482 | |
14bfc3f5 ILT |
483 | case UNDEF * 16 + WEAK_DEF: |
484 | case WEAK_UNDEF * 16 + WEAK_DEF: | |
485 | case DYN_UNDEF * 16 + WEAK_DEF: | |
486 | case DYN_WEAK_UNDEF * 16 + WEAK_DEF: | |
1564db8d | 487 | // A weak definition of a currently undefined symbol. |
86f2e683 | 488 | return true; |
1564db8d | 489 | |
14bfc3f5 ILT |
490 | case COMMON * 16 + WEAK_DEF: |
491 | case WEAK_COMMON * 16 + WEAK_DEF: | |
1564db8d | 492 | // A weak definition does not override a common definition. |
86f2e683 | 493 | return false; |
1564db8d | 494 | |
14bfc3f5 ILT |
495 | case DYN_COMMON * 16 + WEAK_DEF: |
496 | case DYN_WEAK_COMMON * 16 + WEAK_DEF: | |
1564db8d ILT |
497 | // A weak definition does override a definition in a dynamic |
498 | // object. FIXME: We should optionally issue a warning. | |
86f2e683 | 499 | return true; |
14bfc3f5 ILT |
500 | |
501 | case DEF * 16 + DYN_DEF: | |
502 | case WEAK_DEF * 16 + DYN_DEF: | |
503 | case DYN_DEF * 16 + DYN_DEF: | |
504 | case DYN_WEAK_DEF * 16 + DYN_DEF: | |
1564db8d | 505 | // Ignore a dynamic definition if we already have a definition. |
86f2e683 | 506 | return false; |
1564db8d | 507 | |
14bfc3f5 ILT |
508 | case UNDEF * 16 + DYN_DEF: |
509 | case WEAK_UNDEF * 16 + DYN_DEF: | |
510 | case DYN_UNDEF * 16 + DYN_DEF: | |
511 | case DYN_WEAK_UNDEF * 16 + DYN_DEF: | |
1564db8d | 512 | // Use a dynamic definition if we have a reference. |
86f2e683 | 513 | return true; |
1564db8d | 514 | |
14bfc3f5 ILT |
515 | case COMMON * 16 + DYN_DEF: |
516 | case WEAK_COMMON * 16 + DYN_DEF: | |
517 | case DYN_COMMON * 16 + DYN_DEF: | |
518 | case DYN_WEAK_COMMON * 16 + DYN_DEF: | |
1564db8d ILT |
519 | // Ignore a dynamic definition if we already have a common |
520 | // definition. | |
86f2e683 | 521 | return false; |
14bfc3f5 ILT |
522 | |
523 | case DEF * 16 + DYN_WEAK_DEF: | |
524 | case WEAK_DEF * 16 + DYN_WEAK_DEF: | |
525 | case DYN_DEF * 16 + DYN_WEAK_DEF: | |
526 | case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF: | |
1564db8d ILT |
527 | // Ignore a weak dynamic definition if we already have a |
528 | // definition. | |
86f2e683 | 529 | return false; |
1564db8d | 530 | |
14bfc3f5 ILT |
531 | case UNDEF * 16 + DYN_WEAK_DEF: |
532 | case WEAK_UNDEF * 16 + DYN_WEAK_DEF: | |
533 | case DYN_UNDEF * 16 + DYN_WEAK_DEF: | |
534 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF: | |
1564db8d | 535 | // Use a weak dynamic definition if we have a reference. |
86f2e683 | 536 | return true; |
1564db8d | 537 | |
14bfc3f5 ILT |
538 | case COMMON * 16 + DYN_WEAK_DEF: |
539 | case WEAK_COMMON * 16 + DYN_WEAK_DEF: | |
540 | case DYN_COMMON * 16 + DYN_WEAK_DEF: | |
541 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF: | |
1564db8d ILT |
542 | // Ignore a weak dynamic definition if we already have a common |
543 | // definition. | |
86f2e683 | 544 | return false; |
14bfc3f5 ILT |
545 | |
546 | case DEF * 16 + UNDEF: | |
547 | case WEAK_DEF * 16 + UNDEF: | |
548 | case DYN_DEF * 16 + UNDEF: | |
549 | case DYN_WEAK_DEF * 16 + UNDEF: | |
550 | case UNDEF * 16 + UNDEF: | |
ead1e424 | 551 | // A new undefined reference tells us nothing. |
86f2e683 | 552 | return false; |
ead1e424 | 553 | |
14bfc3f5 ILT |
554 | case WEAK_UNDEF * 16 + UNDEF: |
555 | case DYN_UNDEF * 16 + UNDEF: | |
556 | case DYN_WEAK_UNDEF * 16 + UNDEF: | |
ead1e424 | 557 | // A strong undef overrides a dynamic or weak undef. |
86f2e683 | 558 | return true; |
ead1e424 | 559 | |
14bfc3f5 ILT |
560 | case COMMON * 16 + UNDEF: |
561 | case WEAK_COMMON * 16 + UNDEF: | |
562 | case DYN_COMMON * 16 + UNDEF: | |
563 | case DYN_WEAK_COMMON * 16 + UNDEF: | |
1564db8d | 564 | // A new undefined reference tells us nothing. |
86f2e683 | 565 | return false; |
14bfc3f5 ILT |
566 | |
567 | case DEF * 16 + WEAK_UNDEF: | |
568 | case WEAK_DEF * 16 + WEAK_UNDEF: | |
569 | case DYN_DEF * 16 + WEAK_UNDEF: | |
570 | case DYN_WEAK_DEF * 16 + WEAK_UNDEF: | |
571 | case UNDEF * 16 + WEAK_UNDEF: | |
572 | case WEAK_UNDEF * 16 + WEAK_UNDEF: | |
573 | case DYN_UNDEF * 16 + WEAK_UNDEF: | |
574 | case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF: | |
575 | case COMMON * 16 + WEAK_UNDEF: | |
576 | case WEAK_COMMON * 16 + WEAK_UNDEF: | |
577 | case DYN_COMMON * 16 + WEAK_UNDEF: | |
578 | case DYN_WEAK_COMMON * 16 + WEAK_UNDEF: | |
1564db8d | 579 | // A new weak undefined reference tells us nothing. |
86f2e683 | 580 | return false; |
14bfc3f5 ILT |
581 | |
582 | case DEF * 16 + DYN_UNDEF: | |
583 | case WEAK_DEF * 16 + DYN_UNDEF: | |
584 | case DYN_DEF * 16 + DYN_UNDEF: | |
585 | case DYN_WEAK_DEF * 16 + DYN_UNDEF: | |
586 | case UNDEF * 16 + DYN_UNDEF: | |
587 | case WEAK_UNDEF * 16 + DYN_UNDEF: | |
588 | case DYN_UNDEF * 16 + DYN_UNDEF: | |
589 | case DYN_WEAK_UNDEF * 16 + DYN_UNDEF: | |
590 | case COMMON * 16 + DYN_UNDEF: | |
591 | case WEAK_COMMON * 16 + DYN_UNDEF: | |
592 | case DYN_COMMON * 16 + DYN_UNDEF: | |
593 | case DYN_WEAK_COMMON * 16 + DYN_UNDEF: | |
1564db8d | 594 | // A new dynamic undefined reference tells us nothing. |
86f2e683 | 595 | return false; |
14bfc3f5 ILT |
596 | |
597 | case DEF * 16 + DYN_WEAK_UNDEF: | |
598 | case WEAK_DEF * 16 + DYN_WEAK_UNDEF: | |
599 | case DYN_DEF * 16 + DYN_WEAK_UNDEF: | |
600 | case DYN_WEAK_DEF * 16 + DYN_WEAK_UNDEF: | |
601 | case UNDEF * 16 + DYN_WEAK_UNDEF: | |
602 | case WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: | |
603 | case DYN_UNDEF * 16 + DYN_WEAK_UNDEF: | |
604 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: | |
605 | case COMMON * 16 + DYN_WEAK_UNDEF: | |
606 | case WEAK_COMMON * 16 + DYN_WEAK_UNDEF: | |
607 | case DYN_COMMON * 16 + DYN_WEAK_UNDEF: | |
608 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF: | |
1564db8d | 609 | // A new weak dynamic undefined reference tells us nothing. |
86f2e683 | 610 | return false; |
14bfc3f5 ILT |
611 | |
612 | case DEF * 16 + COMMON: | |
1564db8d | 613 | // A common symbol does not override a definition. |
86f2e683 | 614 | return false; |
1564db8d | 615 | |
14bfc3f5 ILT |
616 | case WEAK_DEF * 16 + COMMON: |
617 | case DYN_DEF * 16 + COMMON: | |
618 | case DYN_WEAK_DEF * 16 + COMMON: | |
1564db8d ILT |
619 | // A common symbol does override a weak definition or a dynamic |
620 | // definition. | |
86f2e683 | 621 | return true; |
1564db8d | 622 | |
14bfc3f5 ILT |
623 | case UNDEF * 16 + COMMON: |
624 | case WEAK_UNDEF * 16 + COMMON: | |
625 | case DYN_UNDEF * 16 + COMMON: | |
626 | case DYN_WEAK_UNDEF * 16 + COMMON: | |
1564db8d | 627 | // A common symbol is a definition for a reference. |
86f2e683 | 628 | return true; |
1564db8d | 629 | |
14bfc3f5 | 630 | case COMMON * 16 + COMMON: |
ead1e424 | 631 | // Set the size to the maximum. |
86f2e683 ILT |
632 | *adjust_common_sizes = true; |
633 | return false; | |
ead1e424 | 634 | |
14bfc3f5 | 635 | case WEAK_COMMON * 16 + COMMON: |
ead1e424 ILT |
636 | // I'm not sure just what a weak common symbol means, but |
637 | // presumably it can be overridden by a regular common symbol. | |
86f2e683 | 638 | return true; |
ead1e424 | 639 | |
14bfc3f5 ILT |
640 | case DYN_COMMON * 16 + COMMON: |
641 | case DYN_WEAK_COMMON * 16 + COMMON: | |
86f2e683 ILT |
642 | // Use the real common symbol, but adjust the size if necessary. |
643 | *adjust_common_sizes = true; | |
644 | return true; | |
14bfc3f5 ILT |
645 | |
646 | case DEF * 16 + WEAK_COMMON: | |
647 | case WEAK_DEF * 16 + WEAK_COMMON: | |
648 | case DYN_DEF * 16 + WEAK_COMMON: | |
649 | case DYN_WEAK_DEF * 16 + WEAK_COMMON: | |
ead1e424 ILT |
650 | // Whatever a weak common symbol is, it won't override a |
651 | // definition. | |
86f2e683 | 652 | return false; |
ead1e424 | 653 | |
14bfc3f5 ILT |
654 | case UNDEF * 16 + WEAK_COMMON: |
655 | case WEAK_UNDEF * 16 + WEAK_COMMON: | |
656 | case DYN_UNDEF * 16 + WEAK_COMMON: | |
657 | case DYN_WEAK_UNDEF * 16 + WEAK_COMMON: | |
ead1e424 | 658 | // A weak common symbol is better than an undefined symbol. |
86f2e683 | 659 | return true; |
ead1e424 | 660 | |
14bfc3f5 ILT |
661 | case COMMON * 16 + WEAK_COMMON: |
662 | case WEAK_COMMON * 16 + WEAK_COMMON: | |
663 | case DYN_COMMON * 16 + WEAK_COMMON: | |
664 | case DYN_WEAK_COMMON * 16 + WEAK_COMMON: | |
ead1e424 ILT |
665 | // Ignore a weak common symbol in the presence of a real common |
666 | // symbol. | |
86f2e683 | 667 | return false; |
14bfc3f5 ILT |
668 | |
669 | case DEF * 16 + DYN_COMMON: | |
670 | case WEAK_DEF * 16 + DYN_COMMON: | |
671 | case DYN_DEF * 16 + DYN_COMMON: | |
672 | case DYN_WEAK_DEF * 16 + DYN_COMMON: | |
ead1e424 ILT |
673 | // Ignore a dynamic common symbol in the presence of a |
674 | // definition. | |
86f2e683 | 675 | return false; |
ead1e424 | 676 | |
14bfc3f5 ILT |
677 | case UNDEF * 16 + DYN_COMMON: |
678 | case WEAK_UNDEF * 16 + DYN_COMMON: | |
679 | case DYN_UNDEF * 16 + DYN_COMMON: | |
680 | case DYN_WEAK_UNDEF * 16 + DYN_COMMON: | |
ead1e424 | 681 | // A dynamic common symbol is a definition of sorts. |
86f2e683 | 682 | return true; |
ead1e424 | 683 | |
14bfc3f5 ILT |
684 | case COMMON * 16 + DYN_COMMON: |
685 | case WEAK_COMMON * 16 + DYN_COMMON: | |
686 | case DYN_COMMON * 16 + DYN_COMMON: | |
687 | case DYN_WEAK_COMMON * 16 + DYN_COMMON: | |
ead1e424 | 688 | // Set the size to the maximum. |
86f2e683 ILT |
689 | *adjust_common_sizes = true; |
690 | return false; | |
14bfc3f5 ILT |
691 | |
692 | case DEF * 16 + DYN_WEAK_COMMON: | |
693 | case WEAK_DEF * 16 + DYN_WEAK_COMMON: | |
694 | case DYN_DEF * 16 + DYN_WEAK_COMMON: | |
695 | case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 696 | // A common symbol is ignored in the face of a definition. |
86f2e683 | 697 | return false; |
ead1e424 | 698 | |
14bfc3f5 ILT |
699 | case UNDEF * 16 + DYN_WEAK_COMMON: |
700 | case WEAK_UNDEF * 16 + DYN_WEAK_COMMON: | |
701 | case DYN_UNDEF * 16 + DYN_WEAK_COMMON: | |
702 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 703 | // I guess a weak common symbol is better than a definition. |
86f2e683 | 704 | return true; |
ead1e424 | 705 | |
14bfc3f5 ILT |
706 | case COMMON * 16 + DYN_WEAK_COMMON: |
707 | case WEAK_COMMON * 16 + DYN_WEAK_COMMON: | |
708 | case DYN_COMMON * 16 + DYN_WEAK_COMMON: | |
709 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 710 | // Set the size to the maximum. |
86f2e683 ILT |
711 | *adjust_common_sizes = true; |
712 | return false; | |
1564db8d ILT |
713 | |
714 | default: | |
a3ad94ed | 715 | gold_unreachable(); |
14bfc3f5 ILT |
716 | } |
717 | } | |
718 | ||
86f2e683 ILT |
719 | // A special case of should_override which is only called for a strong |
720 | // defined symbol from a regular object file. This is used when | |
721 | // defining special symbols. | |
722 | ||
723 | bool | |
724 | Symbol_table::should_override_with_special(const Symbol* to) | |
725 | { | |
726 | bool adjust_common_sizes; | |
727 | unsigned int frombits = global_flag | regular_flag | def_flag; | |
d20222a1 ILT |
728 | bool ret = Symbol_table::should_override(to, frombits, NULL, |
729 | &adjust_common_sizes); | |
86f2e683 ILT |
730 | gold_assert(!adjust_common_sizes); |
731 | return ret; | |
732 | } | |
733 | ||
734 | // Override symbol base with a special symbol. | |
735 | ||
736 | void | |
737 | Symbol::override_base_with_special(const Symbol* from) | |
738 | { | |
46fe1623 ILT |
739 | gold_assert(this->name_ == from->name_ || this->has_alias()); |
740 | ||
86f2e683 ILT |
741 | this->source_ = from->source_; |
742 | switch (from->source_) | |
743 | { | |
744 | case FROM_OBJECT: | |
745 | this->u_.from_object = from->u_.from_object; | |
746 | break; | |
747 | case IN_OUTPUT_DATA: | |
748 | this->u_.in_output_data = from->u_.in_output_data; | |
749 | break; | |
750 | case IN_OUTPUT_SEGMENT: | |
751 | this->u_.in_output_segment = from->u_.in_output_segment; | |
752 | break; | |
f3e9c5c5 ILT |
753 | case IS_CONSTANT: |
754 | case IS_UNDEFINED: | |
86f2e683 ILT |
755 | break; |
756 | default: | |
757 | gold_unreachable(); | |
758 | break; | |
759 | } | |
760 | ||
75517b77 | 761 | this->override_version(from->version_); |
86f2e683 ILT |
762 | this->type_ = from->type_; |
763 | this->binding_ = from->binding_; | |
0602e05a | 764 | this->override_visibility(from->visibility_); |
86f2e683 ILT |
765 | this->nonvis_ = from->nonvis_; |
766 | ||
767 | // Special symbols are always considered to be regular symbols. | |
768 | this->in_reg_ = true; | |
46fe1623 ILT |
769 | |
770 | if (from->needs_dynsym_entry_) | |
771 | this->needs_dynsym_entry_ = true; | |
772 | if (from->needs_dynsym_value_) | |
773 | this->needs_dynsym_value_ = true; | |
774 | ||
775 | // We shouldn't see these flags. If we do, we need to handle them | |
776 | // somehow. | |
777 | gold_assert(!from->is_target_special_ || this->is_target_special_); | |
778 | gold_assert(!from->is_forwarder_); | |
46fe1623 ILT |
779 | gold_assert(!from->has_plt_offset_); |
780 | gold_assert(!from->has_warning_); | |
781 | gold_assert(!from->is_copied_from_dynobj_); | |
55a93433 | 782 | gold_assert(!from->is_forced_local_); |
86f2e683 ILT |
783 | } |
784 | ||
785 | // Override a symbol with a special symbol. | |
786 | ||
787 | template<int size> | |
788 | void | |
789 | Sized_symbol<size>::override_with_special(const Sized_symbol<size>* from) | |
790 | { | |
791 | this->override_base_with_special(from); | |
792 | this->value_ = from->value_; | |
793 | this->symsize_ = from->symsize_; | |
794 | } | |
795 | ||
aeddab66 ILT |
796 | // Override TOSYM with the special symbol FROMSYM. This handles all |
797 | // aliases of TOSYM. | |
798 | ||
799 | template<int size> | |
800 | void | |
801 | Symbol_table::override_with_special(Sized_symbol<size>* tosym, | |
802 | const Sized_symbol<size>* fromsym) | |
803 | { | |
804 | tosym->override_with_special(fromsym); | |
805 | if (tosym->has_alias()) | |
806 | { | |
807 | Symbol* sym = this->weak_aliases_[tosym]; | |
808 | gold_assert(sym != NULL); | |
7d1a9ebb | 809 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
810 | do |
811 | { | |
812 | ssym->override_with_special(fromsym); | |
813 | sym = this->weak_aliases_[ssym]; | |
814 | gold_assert(sym != NULL); | |
7d1a9ebb | 815 | ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
816 | } |
817 | while (ssym != tosym); | |
818 | } | |
0602e05a ILT |
819 | if (tosym->binding() == elfcpp::STB_LOCAL |
820 | || ((tosym->visibility() == elfcpp::STV_HIDDEN | |
821 | || tosym->visibility() == elfcpp::STV_INTERNAL) | |
822 | && (tosym->binding() == elfcpp::STB_GLOBAL | |
823 | || tosym->binding() == elfcpp::STB_WEAK) | |
824 | && !parameters->options().relocatable())) | |
55a93433 | 825 | this->force_local(tosym); |
aeddab66 ILT |
826 | } |
827 | ||
14bfc3f5 ILT |
828 | // Instantiate the templates we need. We could use the configure |
829 | // script to restrict this to only the ones needed for implemented | |
830 | // targets. | |
831 | ||
193a53d9 | 832 | #ifdef HAVE_TARGET_32_LITTLE |
14bfc3f5 ILT |
833 | template |
834 | void | |
193a53d9 | 835 | Symbol_table::resolve<32, false>( |
1564db8d | 836 | Sized_symbol<32>* to, |
193a53d9 | 837 | const elfcpp::Sym<32, false>& sym, |
d491d34e ILT |
838 | unsigned int st_shndx, |
839 | bool is_ordinary, | |
840 | unsigned int orig_st_shndx, | |
14b31740 ILT |
841 | Object* object, |
842 | const char* version); | |
193a53d9 | 843 | #endif |
14bfc3f5 | 844 | |
193a53d9 | 845 | #ifdef HAVE_TARGET_32_BIG |
14bfc3f5 ILT |
846 | template |
847 | void | |
193a53d9 | 848 | Symbol_table::resolve<32, true>( |
1564db8d | 849 | Sized_symbol<32>* to, |
193a53d9 | 850 | const elfcpp::Sym<32, true>& sym, |
d491d34e ILT |
851 | unsigned int st_shndx, |
852 | bool is_ordinary, | |
853 | unsigned int orig_st_shndx, | |
14b31740 ILT |
854 | Object* object, |
855 | const char* version); | |
193a53d9 | 856 | #endif |
14bfc3f5 | 857 | |
193a53d9 | 858 | #ifdef HAVE_TARGET_64_LITTLE |
14bfc3f5 ILT |
859 | template |
860 | void | |
193a53d9 | 861 | Symbol_table::resolve<64, false>( |
1564db8d | 862 | Sized_symbol<64>* to, |
193a53d9 | 863 | const elfcpp::Sym<64, false>& sym, |
d491d34e ILT |
864 | unsigned int st_shndx, |
865 | bool is_ordinary, | |
866 | unsigned int orig_st_shndx, | |
14b31740 ILT |
867 | Object* object, |
868 | const char* version); | |
193a53d9 | 869 | #endif |
14bfc3f5 | 870 | |
193a53d9 | 871 | #ifdef HAVE_TARGET_64_BIG |
14bfc3f5 ILT |
872 | template |
873 | void | |
193a53d9 | 874 | Symbol_table::resolve<64, true>( |
1564db8d | 875 | Sized_symbol<64>* to, |
193a53d9 | 876 | const elfcpp::Sym<64, true>& sym, |
d491d34e ILT |
877 | unsigned int st_shndx, |
878 | bool is_ordinary, | |
879 | unsigned int orig_st_shndx, | |
14b31740 ILT |
880 | Object* object, |
881 | const char* version); | |
193a53d9 | 882 | #endif |
14bfc3f5 | 883 | |
86f2e683 ILT |
884 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) |
885 | template | |
886 | void | |
aeddab66 ILT |
887 | Symbol_table::override_with_special<32>(Sized_symbol<32>*, |
888 | const Sized_symbol<32>*); | |
86f2e683 ILT |
889 | #endif |
890 | ||
891 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) | |
892 | template | |
893 | void | |
aeddab66 ILT |
894 | Symbol_table::override_with_special<64>(Sized_symbol<64>*, |
895 | const Sized_symbol<64>*); | |
86f2e683 ILT |
896 | #endif |
897 | ||
14bfc3f5 | 898 | } // End namespace gold. |