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14bfc3f5 ILT |
1 | // resolve.cc -- symbol resolution for gold |
2 | ||
e5756efb | 3 | // Copyright 2006, 2007, 2008 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" | |
29 | ||
30 | namespace gold | |
31 | { | |
32 | ||
1564db8d ILT |
33 | // Symbol methods used in this file. |
34 | ||
75517b77 ILT |
35 | // This symbol is being overridden by another symbol whose version is |
36 | // VERSION. Update the VERSION_ field accordingly. | |
37 | ||
38 | inline void | |
39 | Symbol::override_version(const char* version) | |
40 | { | |
41 | if (version == NULL) | |
42 | { | |
43 | // This is the case where this symbol is NAME/VERSION, and the | |
44 | // version was not marked as hidden. That makes it the default | |
45 | // version, so we create NAME/NULL. Later we see another symbol | |
46 | // NAME/NULL, and that symbol is overriding this one. In this | |
47 | // case, since NAME/VERSION is the default, we make NAME/NULL | |
48 | // override NAME/VERSION as well. They are already the same | |
49 | // Symbol structure. Setting the VERSION_ field to NULL ensures | |
50 | // that it will be output with the correct, empty, version. | |
51 | this->version_ = version; | |
52 | } | |
53 | else | |
54 | { | |
55 | // This is the case where this symbol is NAME/VERSION_ONE, and | |
56 | // now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is | |
57 | // overriding NAME. If VERSION_ONE and VERSION_TWO are | |
58 | // different, then this can only happen when VERSION_ONE is NULL | |
59 | // and VERSION_TWO is not hidden. | |
60 | gold_assert(this->version_ == version || this->version_ == NULL); | |
61 | this->version_ = version; | |
62 | } | |
63 | } | |
64 | ||
1564db8d ILT |
65 | // Override the fields in Symbol. |
66 | ||
67 | template<int size, bool big_endian> | |
68 | void | |
69 | Symbol::override_base(const elfcpp::Sym<size, big_endian>& sym, | |
d491d34e | 70 | unsigned int st_shndx, bool is_ordinary, |
14b31740 | 71 | Object* object, const char* version) |
1564db8d | 72 | { |
a3ad94ed | 73 | gold_assert(this->source_ == FROM_OBJECT); |
ead1e424 | 74 | this->u_.from_object.object = object; |
75517b77 | 75 | this->override_version(version); |
d491d34e ILT |
76 | this->u_.from_object.shndx = st_shndx; |
77 | this->is_ordinary_shndx_ = is_ordinary; | |
1564db8d ILT |
78 | this->type_ = sym.get_st_type(); |
79 | this->binding_ = sym.get_st_bind(); | |
80 | this->visibility_ = sym.get_st_visibility(); | |
ead1e424 | 81 | this->nonvis_ = sym.get_st_nonvis(); |
0d4f1889 ILT |
82 | if (object->is_dynamic()) |
83 | this->in_dyn_ = true; | |
84 | else | |
85 | this->in_reg_ = true; | |
1564db8d ILT |
86 | } |
87 | ||
88 | // Override the fields in Sized_symbol. | |
89 | ||
90 | template<int size> | |
91 | template<bool big_endian> | |
92 | void | |
93 | Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym, | |
d491d34e | 94 | unsigned st_shndx, bool is_ordinary, |
14b31740 | 95 | Object* object, const char* version) |
1564db8d | 96 | { |
d491d34e | 97 | this->override_base(sym, st_shndx, is_ordinary, object, version); |
1564db8d | 98 | this->value_ = sym.get_st_value(); |
ead1e424 | 99 | this->symsize_ = sym.get_st_size(); |
1564db8d ILT |
100 | } |
101 | ||
aeddab66 ILT |
102 | // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version |
103 | // VERSION. This handles all aliases of TOSYM. | |
104 | ||
105 | template<int size, bool big_endian> | |
106 | void | |
107 | Symbol_table::override(Sized_symbol<size>* tosym, | |
108 | const elfcpp::Sym<size, big_endian>& fromsym, | |
d491d34e | 109 | unsigned int st_shndx, bool is_ordinary, |
aeddab66 ILT |
110 | Object* object, const char* version) |
111 | { | |
d491d34e | 112 | tosym->override(fromsym, st_shndx, is_ordinary, object, version); |
aeddab66 ILT |
113 | if (tosym->has_alias()) |
114 | { | |
115 | Symbol* sym = this->weak_aliases_[tosym]; | |
116 | gold_assert(sym != NULL); | |
7d1a9ebb | 117 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
118 | do |
119 | { | |
d491d34e | 120 | ssym->override(fromsym, st_shndx, is_ordinary, object, version); |
aeddab66 ILT |
121 | sym = this->weak_aliases_[ssym]; |
122 | gold_assert(sym != NULL); | |
7d1a9ebb | 123 | ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
124 | } |
125 | while (ssym != tosym); | |
126 | } | |
127 | } | |
128 | ||
86f2e683 ILT |
129 | // The resolve functions build a little code for each symbol. |
130 | // Bit 0: 0 for global, 1 for weak. | |
131 | // Bit 1: 0 for regular object, 1 for shared object | |
132 | // Bits 2-3: 0 for normal, 1 for undefined, 2 for common | |
133 | // This gives us values from 0 to 11. | |
134 | ||
135 | static const int global_or_weak_shift = 0; | |
136 | static const unsigned int global_flag = 0 << global_or_weak_shift; | |
137 | static const unsigned int weak_flag = 1 << global_or_weak_shift; | |
138 | ||
139 | static const int regular_or_dynamic_shift = 1; | |
140 | static const unsigned int regular_flag = 0 << regular_or_dynamic_shift; | |
141 | static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift; | |
142 | ||
143 | static const int def_undef_or_common_shift = 2; | |
144 | static const unsigned int def_flag = 0 << def_undef_or_common_shift; | |
145 | static const unsigned int undef_flag = 1 << def_undef_or_common_shift; | |
146 | static const unsigned int common_flag = 2 << def_undef_or_common_shift; | |
147 | ||
70e654ba ILT |
148 | // This convenience function combines all the flags based on facts |
149 | // about the symbol. | |
150 | ||
151 | static unsigned int | |
152 | symbol_to_bits(elfcpp::STB binding, bool is_dynamic, | |
d491d34e | 153 | unsigned int shndx, bool is_ordinary, elfcpp::STT type) |
70e654ba ILT |
154 | { |
155 | unsigned int bits; | |
156 | ||
157 | switch (binding) | |
158 | { | |
159 | case elfcpp::STB_GLOBAL: | |
160 | bits = global_flag; | |
161 | break; | |
162 | ||
163 | case elfcpp::STB_WEAK: | |
164 | bits = weak_flag; | |
165 | break; | |
166 | ||
167 | case elfcpp::STB_LOCAL: | |
168 | // We should only see externally visible symbols in the symbol | |
169 | // table. | |
170 | gold_error(_("invalid STB_LOCAL symbol in external symbols")); | |
171 | bits = global_flag; | |
172 | ||
173 | default: | |
174 | // Any target which wants to handle STB_LOOS, etc., needs to | |
175 | // define a resolve method. | |
176 | gold_error(_("unsupported symbol binding")); | |
177 | bits = global_flag; | |
178 | } | |
179 | ||
180 | if (is_dynamic) | |
181 | bits |= dynamic_flag; | |
182 | else | |
183 | bits |= regular_flag; | |
184 | ||
185 | switch (shndx) | |
186 | { | |
187 | case elfcpp::SHN_UNDEF: | |
188 | bits |= undef_flag; | |
189 | break; | |
190 | ||
191 | case elfcpp::SHN_COMMON: | |
d491d34e ILT |
192 | if (!is_ordinary) |
193 | bits |= common_flag; | |
70e654ba ILT |
194 | break; |
195 | ||
196 | default: | |
197 | if (type == elfcpp::STT_COMMON) | |
198 | bits |= common_flag; | |
199 | else | |
200 | bits |= def_flag; | |
201 | break; | |
202 | } | |
203 | ||
204 | return bits; | |
205 | } | |
206 | ||
14bfc3f5 | 207 | // Resolve a symbol. This is called the second and subsequent times |
d491d34e ILT |
208 | // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the |
209 | // section index for SYM, possibly adjusted for many sections. | |
210 | // IS_ORDINARY is whether ST_SHNDX is a normal section index rather | |
211 | // than a special code. ORIG_ST_SHNDX is the original section index, | |
212 | // before any munging because of discarded sections, except that all | |
213 | // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION of | |
214 | // the version of SYM. | |
14bfc3f5 ILT |
215 | |
216 | template<int size, bool big_endian> | |
217 | void | |
1564db8d | 218 | Symbol_table::resolve(Sized_symbol<size>* to, |
14bfc3f5 | 219 | const elfcpp::Sym<size, big_endian>& sym, |
d491d34e ILT |
220 | unsigned int st_shndx, bool is_ordinary, |
221 | unsigned int orig_st_shndx, | |
14b31740 | 222 | Object* object, const char* version) |
14bfc3f5 ILT |
223 | { |
224 | if (object->target()->has_resolve()) | |
225 | { | |
274e99f9 | 226 | Sized_target<size, big_endian>* sized_target; |
7d1a9ebb | 227 | sized_target = object->sized_target<size, big_endian>(); |
14b31740 | 228 | sized_target->resolve(to, sym, object, version); |
14bfc3f5 ILT |
229 | return; |
230 | } | |
231 | ||
86f2e683 ILT |
232 | if (!object->is_dynamic()) |
233 | { | |
234 | // Record that we've seen this symbol in a regular object. | |
235 | to->set_in_reg(); | |
236 | } | |
237 | else | |
238 | { | |
239 | // Record that we've seen this symbol in a dynamic object. | |
240 | to->set_in_dyn(); | |
241 | } | |
14bfc3f5 | 242 | |
70e654ba ILT |
243 | unsigned int frombits = symbol_to_bits(sym.get_st_bind(), |
244 | object->is_dynamic(), | |
d491d34e | 245 | st_shndx, is_ordinary, |
70e654ba | 246 | sym.get_st_type()); |
14bfc3f5 | 247 | |
86f2e683 | 248 | bool adjust_common_sizes; |
d20222a1 ILT |
249 | if (Symbol_table::should_override(to, frombits, object, |
250 | &adjust_common_sizes)) | |
86f2e683 ILT |
251 | { |
252 | typename Sized_symbol<size>::Size_type tosize = to->symsize(); | |
253 | ||
d491d34e | 254 | this->override(to, sym, st_shndx, is_ordinary, object, version); |
86f2e683 ILT |
255 | |
256 | if (adjust_common_sizes && tosize > to->symsize()) | |
257 | to->set_symsize(tosize); | |
258 | } | |
259 | else | |
260 | { | |
261 | if (adjust_common_sizes && sym.get_st_size() > to->symsize()) | |
262 | to->set_symsize(sym.get_st_size()); | |
263 | } | |
70e654ba ILT |
264 | |
265 | // A new weak undefined reference, merging with an old weak | |
266 | // reference, could be a One Definition Rule (ODR) violation -- | |
267 | // especially if the types or sizes of the references differ. We'll | |
268 | // store such pairs and look them up later to make sure they | |
269 | // actually refer to the same lines of code. (Note: not all ODR | |
270 | // violations can be found this way, and not everything this finds | |
271 | // is an ODR violation. But it's helpful to warn about.) | |
d491d34e | 272 | bool to_is_ordinary; |
8851ecca | 273 | if (parameters->options().detect_odr_violations() |
d491d34e | 274 | && sym.get_st_bind() == elfcpp::STB_WEAK |
70e654ba | 275 | && to->binding() == elfcpp::STB_WEAK |
d491d34e ILT |
276 | && orig_st_shndx != elfcpp::SHN_UNDEF |
277 | && to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF | |
278 | && to_is_ordinary | |
279 | && sym.get_st_size() != 0 // Ignore weird 0-sized symbols. | |
70e654ba | 280 | && to->symsize() != 0 |
d491d34e ILT |
281 | && (sym.get_st_type() != to->type() |
282 | || sym.get_st_size() != to->symsize()) | |
70e654ba ILT |
283 | // C does not have a concept of ODR, so we only need to do this |
284 | // on C++ symbols. These have (mangled) names starting with _Z. | |
285 | && to->name()[0] == '_' && to->name()[1] == 'Z') | |
286 | { | |
a2b1aa12 | 287 | Symbol_location fromloc |
d491d34e ILT |
288 | = { object, orig_st_shndx, sym.get_st_value() }; |
289 | Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), | |
290 | to->value() }; | |
a2b1aa12 ILT |
291 | this->candidate_odr_violations_[to->name()].insert(fromloc); |
292 | this->candidate_odr_violations_[to->name()].insert(toloc); | |
70e654ba | 293 | } |
86f2e683 ILT |
294 | } |
295 | ||
296 | // Handle the core of symbol resolution. This is called with the | |
297 | // existing symbol, TO, and a bitflag describing the new symbol. This | |
298 | // returns true if we should override the existing symbol with the new | |
299 | // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to | |
300 | // true if we should set the symbol size to the maximum of the TO and | |
301 | // FROM sizes. It handles error conditions. | |
302 | ||
303 | bool | |
304 | Symbol_table::should_override(const Symbol* to, unsigned int frombits, | |
d20222a1 | 305 | Object* object, bool* adjust_common_sizes) |
86f2e683 ILT |
306 | { |
307 | *adjust_common_sizes = false; | |
308 | ||
e5756efb | 309 | unsigned int tobits; |
f3e9c5c5 ILT |
310 | if (to->source() == Symbol::IS_UNDEFINED) |
311 | tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true, | |
312 | to->type()); | |
313 | else if (to->source() != Symbol::FROM_OBJECT) | |
d491d34e | 314 | tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false, |
e5756efb ILT |
315 | to->type()); |
316 | else | |
d491d34e ILT |
317 | { |
318 | bool is_ordinary; | |
319 | unsigned int shndx = to->shndx(&is_ordinary); | |
320 | tobits = symbol_to_bits(to->binding(), | |
321 | to->object()->is_dynamic(), | |
322 | shndx, | |
323 | is_ordinary, | |
324 | to->type()); | |
325 | } | |
14bfc3f5 | 326 | |
1564db8d ILT |
327 | // FIXME: Warn if either but not both of TO and SYM are STT_TLS. |
328 | ||
14bfc3f5 ILT |
329 | // We use a giant switch table for symbol resolution. This code is |
330 | // unwieldy, but: 1) it is efficient; 2) we definitely handle all | |
331 | // cases; 3) it is easy to change the handling of a particular case. | |
332 | // The alternative would be a series of conditionals, but it is easy | |
333 | // to get the ordering wrong. This could also be done as a table, | |
334 | // but that is no easier to understand than this large switch | |
335 | // statement. | |
336 | ||
86f2e683 ILT |
337 | // These are the values generated by the bit codes. |
338 | enum | |
339 | { | |
340 | DEF = global_flag | regular_flag | def_flag, | |
341 | WEAK_DEF = weak_flag | regular_flag | def_flag, | |
342 | DYN_DEF = global_flag | dynamic_flag | def_flag, | |
343 | DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag, | |
344 | UNDEF = global_flag | regular_flag | undef_flag, | |
345 | WEAK_UNDEF = weak_flag | regular_flag | undef_flag, | |
346 | DYN_UNDEF = global_flag | dynamic_flag | undef_flag, | |
347 | DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag, | |
348 | COMMON = global_flag | regular_flag | common_flag, | |
349 | WEAK_COMMON = weak_flag | regular_flag | common_flag, | |
350 | DYN_COMMON = global_flag | dynamic_flag | common_flag, | |
351 | DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag | |
352 | }; | |
353 | ||
14bfc3f5 ILT |
354 | switch (tobits * 16 + frombits) |
355 | { | |
356 | case DEF * 16 + DEF: | |
12e14209 | 357 | // Two definitions of the same symbol. |
878405a8 ILT |
358 | |
359 | // If either symbol is defined by an object included using | |
360 | // --just-symbols, then don't warn. This is for compatibility | |
361 | // with the GNU linker. FIXME: This is a hack. | |
362 | if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols()) | |
363 | || object->just_symbols()) | |
364 | return false; | |
365 | ||
d20222a1 ILT |
366 | // FIXME: Do a better job of reporting locations. |
367 | gold_error(_("%s: multiple definition of %s"), | |
368 | object != NULL ? object->name().c_str() : _("command line"), | |
a2b1aa12 | 369 | to->demangled_name().c_str()); |
d20222a1 ILT |
370 | gold_error(_("%s: previous definition here"), |
371 | (to->source() == Symbol::FROM_OBJECT | |
372 | ? to->object()->name().c_str() | |
373 | : _("command line"))); | |
86f2e683 | 374 | return false; |
14bfc3f5 ILT |
375 | |
376 | case WEAK_DEF * 16 + DEF: | |
1564db8d ILT |
377 | // We've seen a weak definition, and now we see a strong |
378 | // definition. In the original SVR4 linker, this was treated as | |
379 | // a multiple definition error. In the Solaris linker and the | |
380 | // GNU linker, a weak definition followed by a regular | |
381 | // definition causes the weak definition to be overridden. We | |
382 | // are currently compatible with the GNU linker. In the future | |
383 | // we should add a target specific option to change this. | |
384 | // FIXME. | |
86f2e683 | 385 | return true; |
14bfc3f5 ILT |
386 | |
387 | case DYN_DEF * 16 + DEF: | |
388 | case DYN_WEAK_DEF * 16 + DEF: | |
1564db8d ILT |
389 | // We've seen a definition in a dynamic object, and now we see a |
390 | // definition in a regular object. The definition in the | |
391 | // regular object overrides the definition in the dynamic | |
392 | // object. | |
86f2e683 | 393 | return true; |
1564db8d | 394 | |
14bfc3f5 ILT |
395 | case UNDEF * 16 + DEF: |
396 | case WEAK_UNDEF * 16 + DEF: | |
397 | case DYN_UNDEF * 16 + DEF: | |
398 | case DYN_WEAK_UNDEF * 16 + DEF: | |
1564db8d ILT |
399 | // We've seen an undefined reference, and now we see a |
400 | // definition. We use the definition. | |
86f2e683 | 401 | return true; |
1564db8d | 402 | |
14bfc3f5 ILT |
403 | case COMMON * 16 + DEF: |
404 | case WEAK_COMMON * 16 + DEF: | |
405 | case DYN_COMMON * 16 + DEF: | |
406 | case DYN_WEAK_COMMON * 16 + DEF: | |
1564db8d | 407 | // We've seen a common symbol and now we see a definition. The |
14b31740 | 408 | // definition overrides. FIXME: We should optionally issue, version a |
1564db8d | 409 | // warning. |
86f2e683 | 410 | return true; |
14bfc3f5 ILT |
411 | |
412 | case DEF * 16 + WEAK_DEF: | |
413 | case WEAK_DEF * 16 + WEAK_DEF: | |
1564db8d ILT |
414 | // We've seen a definition and now we see a weak definition. We |
415 | // ignore the new weak definition. | |
86f2e683 | 416 | return false; |
1564db8d | 417 | |
14bfc3f5 ILT |
418 | case DYN_DEF * 16 + WEAK_DEF: |
419 | case DYN_WEAK_DEF * 16 + WEAK_DEF: | |
1564db8d ILT |
420 | // We've seen a dynamic definition and now we see a regular weak |
421 | // definition. The regular weak definition overrides. | |
86f2e683 | 422 | return true; |
1564db8d | 423 | |
14bfc3f5 ILT |
424 | case UNDEF * 16 + WEAK_DEF: |
425 | case WEAK_UNDEF * 16 + WEAK_DEF: | |
426 | case DYN_UNDEF * 16 + WEAK_DEF: | |
427 | case DYN_WEAK_UNDEF * 16 + WEAK_DEF: | |
1564db8d | 428 | // A weak definition of a currently undefined symbol. |
86f2e683 | 429 | return true; |
1564db8d | 430 | |
14bfc3f5 ILT |
431 | case COMMON * 16 + WEAK_DEF: |
432 | case WEAK_COMMON * 16 + WEAK_DEF: | |
1564db8d | 433 | // A weak definition does not override a common definition. |
86f2e683 | 434 | return false; |
1564db8d | 435 | |
14bfc3f5 ILT |
436 | case DYN_COMMON * 16 + WEAK_DEF: |
437 | case DYN_WEAK_COMMON * 16 + WEAK_DEF: | |
1564db8d ILT |
438 | // A weak definition does override a definition in a dynamic |
439 | // object. FIXME: We should optionally issue a warning. | |
86f2e683 | 440 | return true; |
14bfc3f5 ILT |
441 | |
442 | case DEF * 16 + DYN_DEF: | |
443 | case WEAK_DEF * 16 + DYN_DEF: | |
444 | case DYN_DEF * 16 + DYN_DEF: | |
445 | case DYN_WEAK_DEF * 16 + DYN_DEF: | |
1564db8d | 446 | // Ignore a dynamic definition if we already have a definition. |
86f2e683 | 447 | return false; |
1564db8d | 448 | |
14bfc3f5 ILT |
449 | case UNDEF * 16 + DYN_DEF: |
450 | case WEAK_UNDEF * 16 + DYN_DEF: | |
451 | case DYN_UNDEF * 16 + DYN_DEF: | |
452 | case DYN_WEAK_UNDEF * 16 + DYN_DEF: | |
1564db8d | 453 | // Use a dynamic definition if we have a reference. |
86f2e683 | 454 | return true; |
1564db8d | 455 | |
14bfc3f5 ILT |
456 | case COMMON * 16 + DYN_DEF: |
457 | case WEAK_COMMON * 16 + DYN_DEF: | |
458 | case DYN_COMMON * 16 + DYN_DEF: | |
459 | case DYN_WEAK_COMMON * 16 + DYN_DEF: | |
1564db8d ILT |
460 | // Ignore a dynamic definition if we already have a common |
461 | // definition. | |
86f2e683 | 462 | return false; |
14bfc3f5 ILT |
463 | |
464 | case DEF * 16 + DYN_WEAK_DEF: | |
465 | case WEAK_DEF * 16 + DYN_WEAK_DEF: | |
466 | case DYN_DEF * 16 + DYN_WEAK_DEF: | |
467 | case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF: | |
1564db8d ILT |
468 | // Ignore a weak dynamic definition if we already have a |
469 | // definition. | |
86f2e683 | 470 | return false; |
1564db8d | 471 | |
14bfc3f5 ILT |
472 | case UNDEF * 16 + DYN_WEAK_DEF: |
473 | case WEAK_UNDEF * 16 + DYN_WEAK_DEF: | |
474 | case DYN_UNDEF * 16 + DYN_WEAK_DEF: | |
475 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF: | |
1564db8d | 476 | // Use a weak dynamic definition if we have a reference. |
86f2e683 | 477 | return true; |
1564db8d | 478 | |
14bfc3f5 ILT |
479 | case COMMON * 16 + DYN_WEAK_DEF: |
480 | case WEAK_COMMON * 16 + DYN_WEAK_DEF: | |
481 | case DYN_COMMON * 16 + DYN_WEAK_DEF: | |
482 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF: | |
1564db8d ILT |
483 | // Ignore a weak dynamic definition if we already have a common |
484 | // definition. | |
86f2e683 | 485 | return false; |
14bfc3f5 ILT |
486 | |
487 | case DEF * 16 + UNDEF: | |
488 | case WEAK_DEF * 16 + UNDEF: | |
489 | case DYN_DEF * 16 + UNDEF: | |
490 | case DYN_WEAK_DEF * 16 + UNDEF: | |
491 | case UNDEF * 16 + UNDEF: | |
ead1e424 | 492 | // A new undefined reference tells us nothing. |
86f2e683 | 493 | return false; |
ead1e424 | 494 | |
14bfc3f5 ILT |
495 | case WEAK_UNDEF * 16 + UNDEF: |
496 | case DYN_UNDEF * 16 + UNDEF: | |
497 | case DYN_WEAK_UNDEF * 16 + UNDEF: | |
ead1e424 | 498 | // A strong undef overrides a dynamic or weak undef. |
86f2e683 | 499 | return true; |
ead1e424 | 500 | |
14bfc3f5 ILT |
501 | case COMMON * 16 + UNDEF: |
502 | case WEAK_COMMON * 16 + UNDEF: | |
503 | case DYN_COMMON * 16 + UNDEF: | |
504 | case DYN_WEAK_COMMON * 16 + UNDEF: | |
1564db8d | 505 | // A new undefined reference tells us nothing. |
86f2e683 | 506 | return false; |
14bfc3f5 ILT |
507 | |
508 | case DEF * 16 + WEAK_UNDEF: | |
509 | case WEAK_DEF * 16 + WEAK_UNDEF: | |
510 | case DYN_DEF * 16 + WEAK_UNDEF: | |
511 | case DYN_WEAK_DEF * 16 + WEAK_UNDEF: | |
512 | case UNDEF * 16 + WEAK_UNDEF: | |
513 | case WEAK_UNDEF * 16 + WEAK_UNDEF: | |
514 | case DYN_UNDEF * 16 + WEAK_UNDEF: | |
515 | case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF: | |
516 | case COMMON * 16 + WEAK_UNDEF: | |
517 | case WEAK_COMMON * 16 + WEAK_UNDEF: | |
518 | case DYN_COMMON * 16 + WEAK_UNDEF: | |
519 | case DYN_WEAK_COMMON * 16 + WEAK_UNDEF: | |
1564db8d | 520 | // A new weak undefined reference tells us nothing. |
86f2e683 | 521 | return false; |
14bfc3f5 ILT |
522 | |
523 | case DEF * 16 + DYN_UNDEF: | |
524 | case WEAK_DEF * 16 + DYN_UNDEF: | |
525 | case DYN_DEF * 16 + DYN_UNDEF: | |
526 | case DYN_WEAK_DEF * 16 + DYN_UNDEF: | |
527 | case UNDEF * 16 + DYN_UNDEF: | |
528 | case WEAK_UNDEF * 16 + DYN_UNDEF: | |
529 | case DYN_UNDEF * 16 + DYN_UNDEF: | |
530 | case DYN_WEAK_UNDEF * 16 + DYN_UNDEF: | |
531 | case COMMON * 16 + DYN_UNDEF: | |
532 | case WEAK_COMMON * 16 + DYN_UNDEF: | |
533 | case DYN_COMMON * 16 + DYN_UNDEF: | |
534 | case DYN_WEAK_COMMON * 16 + DYN_UNDEF: | |
1564db8d | 535 | // A new dynamic undefined reference tells us nothing. |
86f2e683 | 536 | return false; |
14bfc3f5 ILT |
537 | |
538 | case DEF * 16 + DYN_WEAK_UNDEF: | |
539 | case WEAK_DEF * 16 + DYN_WEAK_UNDEF: | |
540 | case DYN_DEF * 16 + DYN_WEAK_UNDEF: | |
541 | case DYN_WEAK_DEF * 16 + DYN_WEAK_UNDEF: | |
542 | case UNDEF * 16 + DYN_WEAK_UNDEF: | |
543 | case WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: | |
544 | case DYN_UNDEF * 16 + DYN_WEAK_UNDEF: | |
545 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: | |
546 | case COMMON * 16 + DYN_WEAK_UNDEF: | |
547 | case WEAK_COMMON * 16 + DYN_WEAK_UNDEF: | |
548 | case DYN_COMMON * 16 + DYN_WEAK_UNDEF: | |
549 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF: | |
1564db8d | 550 | // A new weak dynamic undefined reference tells us nothing. |
86f2e683 | 551 | return false; |
14bfc3f5 ILT |
552 | |
553 | case DEF * 16 + COMMON: | |
1564db8d | 554 | // A common symbol does not override a definition. |
86f2e683 | 555 | return false; |
1564db8d | 556 | |
14bfc3f5 ILT |
557 | case WEAK_DEF * 16 + COMMON: |
558 | case DYN_DEF * 16 + COMMON: | |
559 | case DYN_WEAK_DEF * 16 + COMMON: | |
1564db8d ILT |
560 | // A common symbol does override a weak definition or a dynamic |
561 | // definition. | |
86f2e683 | 562 | return true; |
1564db8d | 563 | |
14bfc3f5 ILT |
564 | case UNDEF * 16 + COMMON: |
565 | case WEAK_UNDEF * 16 + COMMON: | |
566 | case DYN_UNDEF * 16 + COMMON: | |
567 | case DYN_WEAK_UNDEF * 16 + COMMON: | |
1564db8d | 568 | // A common symbol is a definition for a reference. |
86f2e683 | 569 | return true; |
1564db8d | 570 | |
14bfc3f5 | 571 | case COMMON * 16 + COMMON: |
ead1e424 | 572 | // Set the size to the maximum. |
86f2e683 ILT |
573 | *adjust_common_sizes = true; |
574 | return false; | |
ead1e424 | 575 | |
14bfc3f5 | 576 | case WEAK_COMMON * 16 + COMMON: |
ead1e424 ILT |
577 | // I'm not sure just what a weak common symbol means, but |
578 | // presumably it can be overridden by a regular common symbol. | |
86f2e683 | 579 | return true; |
ead1e424 | 580 | |
14bfc3f5 ILT |
581 | case DYN_COMMON * 16 + COMMON: |
582 | case DYN_WEAK_COMMON * 16 + COMMON: | |
86f2e683 ILT |
583 | // Use the real common symbol, but adjust the size if necessary. |
584 | *adjust_common_sizes = true; | |
585 | return true; | |
14bfc3f5 ILT |
586 | |
587 | case DEF * 16 + WEAK_COMMON: | |
588 | case WEAK_DEF * 16 + WEAK_COMMON: | |
589 | case DYN_DEF * 16 + WEAK_COMMON: | |
590 | case DYN_WEAK_DEF * 16 + WEAK_COMMON: | |
ead1e424 ILT |
591 | // Whatever a weak common symbol is, it won't override a |
592 | // definition. | |
86f2e683 | 593 | return false; |
ead1e424 | 594 | |
14bfc3f5 ILT |
595 | case UNDEF * 16 + WEAK_COMMON: |
596 | case WEAK_UNDEF * 16 + WEAK_COMMON: | |
597 | case DYN_UNDEF * 16 + WEAK_COMMON: | |
598 | case DYN_WEAK_UNDEF * 16 + WEAK_COMMON: | |
ead1e424 | 599 | // A weak common symbol is better than an undefined symbol. |
86f2e683 | 600 | return true; |
ead1e424 | 601 | |
14bfc3f5 ILT |
602 | case COMMON * 16 + WEAK_COMMON: |
603 | case WEAK_COMMON * 16 + WEAK_COMMON: | |
604 | case DYN_COMMON * 16 + WEAK_COMMON: | |
605 | case DYN_WEAK_COMMON * 16 + WEAK_COMMON: | |
ead1e424 ILT |
606 | // Ignore a weak common symbol in the presence of a real common |
607 | // symbol. | |
86f2e683 | 608 | return false; |
14bfc3f5 ILT |
609 | |
610 | case DEF * 16 + DYN_COMMON: | |
611 | case WEAK_DEF * 16 + DYN_COMMON: | |
612 | case DYN_DEF * 16 + DYN_COMMON: | |
613 | case DYN_WEAK_DEF * 16 + DYN_COMMON: | |
ead1e424 ILT |
614 | // Ignore a dynamic common symbol in the presence of a |
615 | // definition. | |
86f2e683 | 616 | return false; |
ead1e424 | 617 | |
14bfc3f5 ILT |
618 | case UNDEF * 16 + DYN_COMMON: |
619 | case WEAK_UNDEF * 16 + DYN_COMMON: | |
620 | case DYN_UNDEF * 16 + DYN_COMMON: | |
621 | case DYN_WEAK_UNDEF * 16 + DYN_COMMON: | |
ead1e424 | 622 | // A dynamic common symbol is a definition of sorts. |
86f2e683 | 623 | return true; |
ead1e424 | 624 | |
14bfc3f5 ILT |
625 | case COMMON * 16 + DYN_COMMON: |
626 | case WEAK_COMMON * 16 + DYN_COMMON: | |
627 | case DYN_COMMON * 16 + DYN_COMMON: | |
628 | case DYN_WEAK_COMMON * 16 + DYN_COMMON: | |
ead1e424 | 629 | // Set the size to the maximum. |
86f2e683 ILT |
630 | *adjust_common_sizes = true; |
631 | return false; | |
14bfc3f5 ILT |
632 | |
633 | case DEF * 16 + DYN_WEAK_COMMON: | |
634 | case WEAK_DEF * 16 + DYN_WEAK_COMMON: | |
635 | case DYN_DEF * 16 + DYN_WEAK_COMMON: | |
636 | case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 637 | // A common symbol is ignored in the face of a definition. |
86f2e683 | 638 | return false; |
ead1e424 | 639 | |
14bfc3f5 ILT |
640 | case UNDEF * 16 + DYN_WEAK_COMMON: |
641 | case WEAK_UNDEF * 16 + DYN_WEAK_COMMON: | |
642 | case DYN_UNDEF * 16 + DYN_WEAK_COMMON: | |
643 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 644 | // I guess a weak common symbol is better than a definition. |
86f2e683 | 645 | return true; |
ead1e424 | 646 | |
14bfc3f5 ILT |
647 | case COMMON * 16 + DYN_WEAK_COMMON: |
648 | case WEAK_COMMON * 16 + DYN_WEAK_COMMON: | |
649 | case DYN_COMMON * 16 + DYN_WEAK_COMMON: | |
650 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON: | |
ead1e424 | 651 | // Set the size to the maximum. |
86f2e683 ILT |
652 | *adjust_common_sizes = true; |
653 | return false; | |
1564db8d ILT |
654 | |
655 | default: | |
a3ad94ed | 656 | gold_unreachable(); |
14bfc3f5 ILT |
657 | } |
658 | } | |
659 | ||
86f2e683 ILT |
660 | // A special case of should_override which is only called for a strong |
661 | // defined symbol from a regular object file. This is used when | |
662 | // defining special symbols. | |
663 | ||
664 | bool | |
665 | Symbol_table::should_override_with_special(const Symbol* to) | |
666 | { | |
667 | bool adjust_common_sizes; | |
668 | unsigned int frombits = global_flag | regular_flag | def_flag; | |
d20222a1 ILT |
669 | bool ret = Symbol_table::should_override(to, frombits, NULL, |
670 | &adjust_common_sizes); | |
86f2e683 ILT |
671 | gold_assert(!adjust_common_sizes); |
672 | return ret; | |
673 | } | |
674 | ||
675 | // Override symbol base with a special symbol. | |
676 | ||
677 | void | |
678 | Symbol::override_base_with_special(const Symbol* from) | |
679 | { | |
46fe1623 ILT |
680 | gold_assert(this->name_ == from->name_ || this->has_alias()); |
681 | ||
86f2e683 ILT |
682 | this->source_ = from->source_; |
683 | switch (from->source_) | |
684 | { | |
685 | case FROM_OBJECT: | |
686 | this->u_.from_object = from->u_.from_object; | |
687 | break; | |
688 | case IN_OUTPUT_DATA: | |
689 | this->u_.in_output_data = from->u_.in_output_data; | |
690 | break; | |
691 | case IN_OUTPUT_SEGMENT: | |
692 | this->u_.in_output_segment = from->u_.in_output_segment; | |
693 | break; | |
f3e9c5c5 ILT |
694 | case IS_CONSTANT: |
695 | case IS_UNDEFINED: | |
86f2e683 ILT |
696 | break; |
697 | default: | |
698 | gold_unreachable(); | |
699 | break; | |
700 | } | |
701 | ||
75517b77 | 702 | this->override_version(from->version_); |
86f2e683 ILT |
703 | this->type_ = from->type_; |
704 | this->binding_ = from->binding_; | |
705 | this->visibility_ = from->visibility_; | |
706 | this->nonvis_ = from->nonvis_; | |
707 | ||
708 | // Special symbols are always considered to be regular symbols. | |
709 | this->in_reg_ = true; | |
46fe1623 ILT |
710 | |
711 | if (from->needs_dynsym_entry_) | |
712 | this->needs_dynsym_entry_ = true; | |
713 | if (from->needs_dynsym_value_) | |
714 | this->needs_dynsym_value_ = true; | |
715 | ||
716 | // We shouldn't see these flags. If we do, we need to handle them | |
717 | // somehow. | |
718 | gold_assert(!from->is_target_special_ || this->is_target_special_); | |
719 | gold_assert(!from->is_forwarder_); | |
46fe1623 ILT |
720 | gold_assert(!from->has_plt_offset_); |
721 | gold_assert(!from->has_warning_); | |
722 | gold_assert(!from->is_copied_from_dynobj_); | |
55a93433 | 723 | gold_assert(!from->is_forced_local_); |
86f2e683 ILT |
724 | } |
725 | ||
726 | // Override a symbol with a special symbol. | |
727 | ||
728 | template<int size> | |
729 | void | |
730 | Sized_symbol<size>::override_with_special(const Sized_symbol<size>* from) | |
731 | { | |
732 | this->override_base_with_special(from); | |
733 | this->value_ = from->value_; | |
734 | this->symsize_ = from->symsize_; | |
735 | } | |
736 | ||
aeddab66 ILT |
737 | // Override TOSYM with the special symbol FROMSYM. This handles all |
738 | // aliases of TOSYM. | |
739 | ||
740 | template<int size> | |
741 | void | |
742 | Symbol_table::override_with_special(Sized_symbol<size>* tosym, | |
743 | const Sized_symbol<size>* fromsym) | |
744 | { | |
745 | tosym->override_with_special(fromsym); | |
746 | if (tosym->has_alias()) | |
747 | { | |
748 | Symbol* sym = this->weak_aliases_[tosym]; | |
749 | gold_assert(sym != NULL); | |
7d1a9ebb | 750 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
751 | do |
752 | { | |
753 | ssym->override_with_special(fromsym); | |
754 | sym = this->weak_aliases_[ssym]; | |
755 | gold_assert(sym != NULL); | |
7d1a9ebb | 756 | ssym = this->get_sized_symbol<size>(sym); |
aeddab66 ILT |
757 | } |
758 | while (ssym != tosym); | |
759 | } | |
55a93433 ILT |
760 | if (tosym->binding() == elfcpp::STB_LOCAL) |
761 | this->force_local(tosym); | |
aeddab66 ILT |
762 | } |
763 | ||
14bfc3f5 ILT |
764 | // Instantiate the templates we need. We could use the configure |
765 | // script to restrict this to only the ones needed for implemented | |
766 | // targets. | |
767 | ||
193a53d9 | 768 | #ifdef HAVE_TARGET_32_LITTLE |
14bfc3f5 ILT |
769 | template |
770 | void | |
193a53d9 | 771 | Symbol_table::resolve<32, false>( |
1564db8d | 772 | Sized_symbol<32>* to, |
193a53d9 | 773 | const elfcpp::Sym<32, false>& sym, |
d491d34e ILT |
774 | unsigned int st_shndx, |
775 | bool is_ordinary, | |
776 | unsigned int orig_st_shndx, | |
14b31740 ILT |
777 | Object* object, |
778 | const char* version); | |
193a53d9 | 779 | #endif |
14bfc3f5 | 780 | |
193a53d9 | 781 | #ifdef HAVE_TARGET_32_BIG |
14bfc3f5 ILT |
782 | template |
783 | void | |
193a53d9 | 784 | Symbol_table::resolve<32, true>( |
1564db8d | 785 | Sized_symbol<32>* to, |
193a53d9 | 786 | const elfcpp::Sym<32, true>& sym, |
d491d34e ILT |
787 | unsigned int st_shndx, |
788 | bool is_ordinary, | |
789 | unsigned int orig_st_shndx, | |
14b31740 ILT |
790 | Object* object, |
791 | const char* version); | |
193a53d9 | 792 | #endif |
14bfc3f5 | 793 | |
193a53d9 | 794 | #ifdef HAVE_TARGET_64_LITTLE |
14bfc3f5 ILT |
795 | template |
796 | void | |
193a53d9 | 797 | Symbol_table::resolve<64, false>( |
1564db8d | 798 | Sized_symbol<64>* to, |
193a53d9 | 799 | const elfcpp::Sym<64, false>& sym, |
d491d34e ILT |
800 | unsigned int st_shndx, |
801 | bool is_ordinary, | |
802 | unsigned int orig_st_shndx, | |
14b31740 ILT |
803 | Object* object, |
804 | const char* version); | |
193a53d9 | 805 | #endif |
14bfc3f5 | 806 | |
193a53d9 | 807 | #ifdef HAVE_TARGET_64_BIG |
14bfc3f5 ILT |
808 | template |
809 | void | |
193a53d9 | 810 | Symbol_table::resolve<64, true>( |
1564db8d | 811 | Sized_symbol<64>* to, |
193a53d9 | 812 | const elfcpp::Sym<64, true>& sym, |
d491d34e ILT |
813 | unsigned int st_shndx, |
814 | bool is_ordinary, | |
815 | unsigned int orig_st_shndx, | |
14b31740 ILT |
816 | Object* object, |
817 | const char* version); | |
193a53d9 | 818 | #endif |
14bfc3f5 | 819 | |
86f2e683 ILT |
820 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) |
821 | template | |
822 | void | |
aeddab66 ILT |
823 | Symbol_table::override_with_special<32>(Sized_symbol<32>*, |
824 | const Sized_symbol<32>*); | |
86f2e683 ILT |
825 | #endif |
826 | ||
827 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) | |
828 | template | |
829 | void | |
aeddab66 ILT |
830 | Symbol_table::override_with_special<64>(Sized_symbol<64>*, |
831 | const Sized_symbol<64>*); | |
86f2e683 ILT |
832 | #endif |
833 | ||
14bfc3f5 | 834 | } // End namespace gold. |