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