| 1 | // resolve.cc -- symbol resolution for gold |
| 2 | |
| 3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
| 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 | |
| 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 | |
| 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, |
| 40 | Object* object, const char* version) |
| 41 | { |
| 42 | gold_assert(this->source_ == FROM_OBJECT); |
| 43 | this->u_.from_object.object = object; |
| 44 | if (version != NULL && this->version() != version) |
| 45 | { |
| 46 | gold_assert(this->version() == NULL); |
| 47 | this->version_ = version; |
| 48 | } |
| 49 | // FIXME: Handle SHN_XINDEX. |
| 50 | this->u_.from_object.shndx = sym.get_st_shndx(); |
| 51 | this->type_ = sym.get_st_type(); |
| 52 | this->binding_ = sym.get_st_bind(); |
| 53 | this->visibility_ = sym.get_st_visibility(); |
| 54 | this->nonvis_ = sym.get_st_nonvis(); |
| 55 | if (object->is_dynamic()) |
| 56 | this->in_dyn_ = true; |
| 57 | else |
| 58 | this->in_reg_ = true; |
| 59 | } |
| 60 | |
| 61 | // Override the fields in Sized_symbol. |
| 62 | |
| 63 | template<int size> |
| 64 | template<bool big_endian> |
| 65 | void |
| 66 | Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym, |
| 67 | Object* object, const char* version) |
| 68 | { |
| 69 | this->override_base(sym, object, version); |
| 70 | this->value_ = sym.get_st_value(); |
| 71 | this->symsize_ = sym.get_st_size(); |
| 72 | } |
| 73 | |
| 74 | // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version |
| 75 | // VERSION. This handles all aliases of TOSYM. |
| 76 | |
| 77 | template<int size, bool big_endian> |
| 78 | void |
| 79 | Symbol_table::override(Sized_symbol<size>* tosym, |
| 80 | const elfcpp::Sym<size, big_endian>& fromsym, |
| 81 | Object* object, const char* version) |
| 82 | { |
| 83 | tosym->override(fromsym, object, version); |
| 84 | if (tosym->has_alias()) |
| 85 | { |
| 86 | Symbol* sym = this->weak_aliases_[tosym]; |
| 87 | gold_assert(sym != NULL); |
| 88 | Sized_symbol<size>* ssym; |
| 89 | ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym |
| 90 | SELECT_SIZE(size)); |
| 91 | do |
| 92 | { |
| 93 | ssym->override(fromsym, object, version); |
| 94 | sym = this->weak_aliases_[ssym]; |
| 95 | gold_assert(sym != NULL); |
| 96 | ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) ( |
| 97 | sym SELECT_SIZE(size)); |
| 98 | } |
| 99 | while (ssym != tosym); |
| 100 | } |
| 101 | } |
| 102 | |
| 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 | |
| 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, |
| 127 | unsigned int shndx, elfcpp::STT type) |
| 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: |
| 166 | bits |= common_flag; |
| 167 | break; |
| 168 | |
| 169 | default: |
| 170 | if (type == elfcpp::STT_COMMON) |
| 171 | bits |= common_flag; |
| 172 | else |
| 173 | bits |= def_flag; |
| 174 | break; |
| 175 | } |
| 176 | |
| 177 | return bits; |
| 178 | } |
| 179 | |
| 180 | // Resolve a symbol. This is called the second and subsequent times |
| 181 | // we see a symbol. TO is the pre-existing symbol. ORIG_SYM is the |
| 182 | // new symbol, seen in OBJECT. SYM is almost always identical to |
| 183 | // ORIG_SYM, but may be munged (for instance, if we determine the |
| 184 | // symbol is in a to-be-discarded section, we'll set sym's shndx to |
| 185 | // UNDEFINED). VERSION of the version of SYM. |
| 186 | |
| 187 | template<int size, bool big_endian> |
| 188 | void |
| 189 | Symbol_table::resolve(Sized_symbol<size>* to, |
| 190 | const elfcpp::Sym<size, big_endian>& sym, |
| 191 | const elfcpp::Sym<size, big_endian>& orig_sym, |
| 192 | Object* object, const char* version) |
| 193 | { |
| 194 | if (object->target()->has_resolve()) |
| 195 | { |
| 196 | Sized_target<size, big_endian>* sized_target; |
| 197 | sized_target = object->sized_target |
| 198 | SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( |
| 199 | SELECT_SIZE_ENDIAN_ONLY(size, big_endian)); |
| 200 | sized_target->resolve(to, sym, object, version); |
| 201 | return; |
| 202 | } |
| 203 | |
| 204 | if (!object->is_dynamic()) |
| 205 | { |
| 206 | // Record that we've seen this symbol in a regular object. |
| 207 | to->set_in_reg(); |
| 208 | } |
| 209 | else |
| 210 | { |
| 211 | // Record that we've seen this symbol in a dynamic object. |
| 212 | to->set_in_dyn(); |
| 213 | } |
| 214 | |
| 215 | unsigned int frombits = symbol_to_bits(sym.get_st_bind(), |
| 216 | object->is_dynamic(), |
| 217 | sym.get_st_shndx(), |
| 218 | sym.get_st_type()); |
| 219 | |
| 220 | bool adjust_common_sizes; |
| 221 | if (Symbol_table::should_override(to, frombits, object, |
| 222 | &adjust_common_sizes)) |
| 223 | { |
| 224 | typename Sized_symbol<size>::Size_type tosize = to->symsize(); |
| 225 | |
| 226 | this->override(to, sym, object, version); |
| 227 | |
| 228 | if (adjust_common_sizes && tosize > to->symsize()) |
| 229 | to->set_symsize(tosize); |
| 230 | } |
| 231 | else |
| 232 | { |
| 233 | if (adjust_common_sizes && sym.get_st_size() > to->symsize()) |
| 234 | to->set_symsize(sym.get_st_size()); |
| 235 | } |
| 236 | |
| 237 | // A new weak undefined reference, merging with an old weak |
| 238 | // reference, could be a One Definition Rule (ODR) violation -- |
| 239 | // especially if the types or sizes of the references differ. We'll |
| 240 | // store such pairs and look them up later to make sure they |
| 241 | // actually refer to the same lines of code. (Note: not all ODR |
| 242 | // violations can be found this way, and not everything this finds |
| 243 | // is an ODR violation. But it's helpful to warn about.) |
| 244 | // We use orig_sym here because we want the symbol exactly as it |
| 245 | // appears in the object file, not munged via our future processing. |
| 246 | if (parameters->detect_odr_violations() |
| 247 | && orig_sym.get_st_bind() == elfcpp::STB_WEAK |
| 248 | && to->binding() == elfcpp::STB_WEAK |
| 249 | && orig_sym.get_st_shndx() != elfcpp::SHN_UNDEF |
| 250 | && to->shndx() != elfcpp::SHN_UNDEF |
| 251 | && orig_sym.get_st_size() != 0 // Ignore weird 0-sized symbols. |
| 252 | && to->symsize() != 0 |
| 253 | && (orig_sym.get_st_type() != to->type() |
| 254 | || orig_sym.get_st_size() != to->symsize()) |
| 255 | // C does not have a concept of ODR, so we only need to do this |
| 256 | // on C++ symbols. These have (mangled) names starting with _Z. |
| 257 | && to->name()[0] == '_' && to->name()[1] == 'Z') |
| 258 | { |
| 259 | Symbol_location from_location |
| 260 | = { object, orig_sym.get_st_shndx(), orig_sym.get_st_value() }; |
| 261 | Symbol_location to_location = { to->object(), to->shndx(), to->value() }; |
| 262 | this->candidate_odr_violations_[to->name()].insert(from_location); |
| 263 | this->candidate_odr_violations_[to->name()].insert(to_location); |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | // Handle the core of symbol resolution. This is called with the |
| 268 | // existing symbol, TO, and a bitflag describing the new symbol. This |
| 269 | // returns true if we should override the existing symbol with the new |
| 270 | // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to |
| 271 | // true if we should set the symbol size to the maximum of the TO and |
| 272 | // FROM sizes. It handles error conditions. |
| 273 | |
| 274 | bool |
| 275 | Symbol_table::should_override(const Symbol* to, unsigned int frombits, |
| 276 | Object* object, bool* adjust_common_sizes) |
| 277 | { |
| 278 | *adjust_common_sizes = false; |
| 279 | |
| 280 | unsigned int tobits = symbol_to_bits(to->binding(), |
| 281 | (to->source() == Symbol::FROM_OBJECT |
| 282 | && to->object()->is_dynamic()), |
| 283 | to->shndx(), |
| 284 | to->type()); |
| 285 | |
| 286 | // FIXME: Warn if either but not both of TO and SYM are STT_TLS. |
| 287 | |
| 288 | // We use a giant switch table for symbol resolution. This code is |
| 289 | // unwieldy, but: 1) it is efficient; 2) we definitely handle all |
| 290 | // cases; 3) it is easy to change the handling of a particular case. |
| 291 | // The alternative would be a series of conditionals, but it is easy |
| 292 | // to get the ordering wrong. This could also be done as a table, |
| 293 | // but that is no easier to understand than this large switch |
| 294 | // statement. |
| 295 | |
| 296 | // These are the values generated by the bit codes. |
| 297 | enum |
| 298 | { |
| 299 | DEF = global_flag | regular_flag | def_flag, |
| 300 | WEAK_DEF = weak_flag | regular_flag | def_flag, |
| 301 | DYN_DEF = global_flag | dynamic_flag | def_flag, |
| 302 | DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag, |
| 303 | UNDEF = global_flag | regular_flag | undef_flag, |
| 304 | WEAK_UNDEF = weak_flag | regular_flag | undef_flag, |
| 305 | DYN_UNDEF = global_flag | dynamic_flag | undef_flag, |
| 306 | DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag, |
| 307 | COMMON = global_flag | regular_flag | common_flag, |
| 308 | WEAK_COMMON = weak_flag | regular_flag | common_flag, |
| 309 | DYN_COMMON = global_flag | dynamic_flag | common_flag, |
| 310 | DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag |
| 311 | }; |
| 312 | |
| 313 | switch (tobits * 16 + frombits) |
| 314 | { |
| 315 | case DEF * 16 + DEF: |
| 316 | // Two definitions of the same symbol. |
| 317 | // FIXME: Do a better job of reporting locations. |
| 318 | gold_error(_("%s: multiple definition of %s"), |
| 319 | object != NULL ? object->name().c_str() : _("command line"), |
| 320 | to->name()); |
| 321 | gold_error(_("%s: previous definition here"), |
| 322 | (to->source() == Symbol::FROM_OBJECT |
| 323 | ? to->object()->name().c_str() |
| 324 | : _("command line"))); |
| 325 | return false; |
| 326 | |
| 327 | case WEAK_DEF * 16 + DEF: |
| 328 | // We've seen a weak definition, and now we see a strong |
| 329 | // definition. In the original SVR4 linker, this was treated as |
| 330 | // a multiple definition error. In the Solaris linker and the |
| 331 | // GNU linker, a weak definition followed by a regular |
| 332 | // definition causes the weak definition to be overridden. We |
| 333 | // are currently compatible with the GNU linker. In the future |
| 334 | // we should add a target specific option to change this. |
| 335 | // FIXME. |
| 336 | return true; |
| 337 | |
| 338 | case DYN_DEF * 16 + DEF: |
| 339 | case DYN_WEAK_DEF * 16 + DEF: |
| 340 | // We've seen a definition in a dynamic object, and now we see a |
| 341 | // definition in a regular object. The definition in the |
| 342 | // regular object overrides the definition in the dynamic |
| 343 | // object. |
| 344 | return true; |
| 345 | |
| 346 | case UNDEF * 16 + DEF: |
| 347 | case WEAK_UNDEF * 16 + DEF: |
| 348 | case DYN_UNDEF * 16 + DEF: |
| 349 | case DYN_WEAK_UNDEF * 16 + DEF: |
| 350 | // We've seen an undefined reference, and now we see a |
| 351 | // definition. We use the definition. |
| 352 | return true; |
| 353 | |
| 354 | case COMMON * 16 + DEF: |
| 355 | case WEAK_COMMON * 16 + DEF: |
| 356 | case DYN_COMMON * 16 + DEF: |
| 357 | case DYN_WEAK_COMMON * 16 + DEF: |
| 358 | // We've seen a common symbol and now we see a definition. The |
| 359 | // definition overrides. FIXME: We should optionally issue, version a |
| 360 | // warning. |
| 361 | return true; |
| 362 | |
| 363 | case DEF * 16 + WEAK_DEF: |
| 364 | case WEAK_DEF * 16 + WEAK_DEF: |
| 365 | // We've seen a definition and now we see a weak definition. We |
| 366 | // ignore the new weak definition. |
| 367 | return false; |
| 368 | |
| 369 | case DYN_DEF * 16 + WEAK_DEF: |
| 370 | case DYN_WEAK_DEF * 16 + WEAK_DEF: |
| 371 | // We've seen a dynamic definition and now we see a regular weak |
| 372 | // definition. The regular weak definition overrides. |
| 373 | return true; |
| 374 | |
| 375 | case UNDEF * 16 + WEAK_DEF: |
| 376 | case WEAK_UNDEF * 16 + WEAK_DEF: |
| 377 | case DYN_UNDEF * 16 + WEAK_DEF: |
| 378 | case DYN_WEAK_UNDEF * 16 + WEAK_DEF: |
| 379 | // A weak definition of a currently undefined symbol. |
| 380 | return true; |
| 381 | |
| 382 | case COMMON * 16 + WEAK_DEF: |
| 383 | case WEAK_COMMON * 16 + WEAK_DEF: |
| 384 | // A weak definition does not override a common definition. |
| 385 | return false; |
| 386 | |
| 387 | case DYN_COMMON * 16 + WEAK_DEF: |
| 388 | case DYN_WEAK_COMMON * 16 + WEAK_DEF: |
| 389 | // A weak definition does override a definition in a dynamic |
| 390 | // object. FIXME: We should optionally issue a warning. |
| 391 | return true; |
| 392 | |
| 393 | case DEF * 16 + DYN_DEF: |
| 394 | case WEAK_DEF * 16 + DYN_DEF: |
| 395 | case DYN_DEF * 16 + DYN_DEF: |
| 396 | case DYN_WEAK_DEF * 16 + DYN_DEF: |
| 397 | // Ignore a dynamic definition if we already have a definition. |
| 398 | return false; |
| 399 | |
| 400 | case UNDEF * 16 + DYN_DEF: |
| 401 | case WEAK_UNDEF * 16 + DYN_DEF: |
| 402 | case DYN_UNDEF * 16 + DYN_DEF: |
| 403 | case DYN_WEAK_UNDEF * 16 + DYN_DEF: |
| 404 | // Use a dynamic definition if we have a reference. |
| 405 | return true; |
| 406 | |
| 407 | case COMMON * 16 + DYN_DEF: |
| 408 | case WEAK_COMMON * 16 + DYN_DEF: |
| 409 | case DYN_COMMON * 16 + DYN_DEF: |
| 410 | case DYN_WEAK_COMMON * 16 + DYN_DEF: |
| 411 | // Ignore a dynamic definition if we already have a common |
| 412 | // definition. |
| 413 | return false; |
| 414 | |
| 415 | case DEF * 16 + DYN_WEAK_DEF: |
| 416 | case WEAK_DEF * 16 + DYN_WEAK_DEF: |
| 417 | case DYN_DEF * 16 + DYN_WEAK_DEF: |
| 418 | case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF: |
| 419 | // Ignore a weak dynamic definition if we already have a |
| 420 | // definition. |
| 421 | return false; |
| 422 | |
| 423 | case UNDEF * 16 + DYN_WEAK_DEF: |
| 424 | case WEAK_UNDEF * 16 + DYN_WEAK_DEF: |
| 425 | case DYN_UNDEF * 16 + DYN_WEAK_DEF: |
| 426 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF: |
| 427 | // Use a weak dynamic definition if we have a reference. |
| 428 | return true; |
| 429 | |
| 430 | case COMMON * 16 + DYN_WEAK_DEF: |
| 431 | case WEAK_COMMON * 16 + DYN_WEAK_DEF: |
| 432 | case DYN_COMMON * 16 + DYN_WEAK_DEF: |
| 433 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF: |
| 434 | // Ignore a weak dynamic definition if we already have a common |
| 435 | // definition. |
| 436 | return false; |
| 437 | |
| 438 | case DEF * 16 + UNDEF: |
| 439 | case WEAK_DEF * 16 + UNDEF: |
| 440 | case DYN_DEF * 16 + UNDEF: |
| 441 | case DYN_WEAK_DEF * 16 + UNDEF: |
| 442 | case UNDEF * 16 + UNDEF: |
| 443 | // A new undefined reference tells us nothing. |
| 444 | return false; |
| 445 | |
| 446 | case WEAK_UNDEF * 16 + UNDEF: |
| 447 | case DYN_UNDEF * 16 + UNDEF: |
| 448 | case DYN_WEAK_UNDEF * 16 + UNDEF: |
| 449 | // A strong undef overrides a dynamic or weak undef. |
| 450 | return true; |
| 451 | |
| 452 | case COMMON * 16 + UNDEF: |
| 453 | case WEAK_COMMON * 16 + UNDEF: |
| 454 | case DYN_COMMON * 16 + UNDEF: |
| 455 | case DYN_WEAK_COMMON * 16 + UNDEF: |
| 456 | // A new undefined reference tells us nothing. |
| 457 | return false; |
| 458 | |
| 459 | case DEF * 16 + WEAK_UNDEF: |
| 460 | case WEAK_DEF * 16 + WEAK_UNDEF: |
| 461 | case DYN_DEF * 16 + WEAK_UNDEF: |
| 462 | case DYN_WEAK_DEF * 16 + WEAK_UNDEF: |
| 463 | case UNDEF * 16 + WEAK_UNDEF: |
| 464 | case WEAK_UNDEF * 16 + WEAK_UNDEF: |
| 465 | case DYN_UNDEF * 16 + WEAK_UNDEF: |
| 466 | case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF: |
| 467 | case COMMON * 16 + WEAK_UNDEF: |
| 468 | case WEAK_COMMON * 16 + WEAK_UNDEF: |
| 469 | case DYN_COMMON * 16 + WEAK_UNDEF: |
| 470 | case DYN_WEAK_COMMON * 16 + WEAK_UNDEF: |
| 471 | // A new weak undefined reference tells us nothing. |
| 472 | return false; |
| 473 | |
| 474 | case DEF * 16 + DYN_UNDEF: |
| 475 | case WEAK_DEF * 16 + DYN_UNDEF: |
| 476 | case DYN_DEF * 16 + DYN_UNDEF: |
| 477 | case DYN_WEAK_DEF * 16 + DYN_UNDEF: |
| 478 | case UNDEF * 16 + DYN_UNDEF: |
| 479 | case WEAK_UNDEF * 16 + DYN_UNDEF: |
| 480 | case DYN_UNDEF * 16 + DYN_UNDEF: |
| 481 | case DYN_WEAK_UNDEF * 16 + DYN_UNDEF: |
| 482 | case COMMON * 16 + DYN_UNDEF: |
| 483 | case WEAK_COMMON * 16 + DYN_UNDEF: |
| 484 | case DYN_COMMON * 16 + DYN_UNDEF: |
| 485 | case DYN_WEAK_COMMON * 16 + DYN_UNDEF: |
| 486 | // A new dynamic undefined reference tells us nothing. |
| 487 | return false; |
| 488 | |
| 489 | case DEF * 16 + DYN_WEAK_UNDEF: |
| 490 | case WEAK_DEF * 16 + DYN_WEAK_UNDEF: |
| 491 | case DYN_DEF * 16 + DYN_WEAK_UNDEF: |
| 492 | case DYN_WEAK_DEF * 16 + DYN_WEAK_UNDEF: |
| 493 | case UNDEF * 16 + DYN_WEAK_UNDEF: |
| 494 | case WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: |
| 495 | case DYN_UNDEF * 16 + DYN_WEAK_UNDEF: |
| 496 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: |
| 497 | case COMMON * 16 + DYN_WEAK_UNDEF: |
| 498 | case WEAK_COMMON * 16 + DYN_WEAK_UNDEF: |
| 499 | case DYN_COMMON * 16 + DYN_WEAK_UNDEF: |
| 500 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF: |
| 501 | // A new weak dynamic undefined reference tells us nothing. |
| 502 | return false; |
| 503 | |
| 504 | case DEF * 16 + COMMON: |
| 505 | // A common symbol does not override a definition. |
| 506 | return false; |
| 507 | |
| 508 | case WEAK_DEF * 16 + COMMON: |
| 509 | case DYN_DEF * 16 + COMMON: |
| 510 | case DYN_WEAK_DEF * 16 + COMMON: |
| 511 | // A common symbol does override a weak definition or a dynamic |
| 512 | // definition. |
| 513 | return true; |
| 514 | |
| 515 | case UNDEF * 16 + COMMON: |
| 516 | case WEAK_UNDEF * 16 + COMMON: |
| 517 | case DYN_UNDEF * 16 + COMMON: |
| 518 | case DYN_WEAK_UNDEF * 16 + COMMON: |
| 519 | // A common symbol is a definition for a reference. |
| 520 | return true; |
| 521 | |
| 522 | case COMMON * 16 + COMMON: |
| 523 | // Set the size to the maximum. |
| 524 | *adjust_common_sizes = true; |
| 525 | return false; |
| 526 | |
| 527 | case WEAK_COMMON * 16 + COMMON: |
| 528 | // I'm not sure just what a weak common symbol means, but |
| 529 | // presumably it can be overridden by a regular common symbol. |
| 530 | return true; |
| 531 | |
| 532 | case DYN_COMMON * 16 + COMMON: |
| 533 | case DYN_WEAK_COMMON * 16 + COMMON: |
| 534 | // Use the real common symbol, but adjust the size if necessary. |
| 535 | *adjust_common_sizes = true; |
| 536 | return true; |
| 537 | |
| 538 | case DEF * 16 + WEAK_COMMON: |
| 539 | case WEAK_DEF * 16 + WEAK_COMMON: |
| 540 | case DYN_DEF * 16 + WEAK_COMMON: |
| 541 | case DYN_WEAK_DEF * 16 + WEAK_COMMON: |
| 542 | // Whatever a weak common symbol is, it won't override a |
| 543 | // definition. |
| 544 | return false; |
| 545 | |
| 546 | case UNDEF * 16 + WEAK_COMMON: |
| 547 | case WEAK_UNDEF * 16 + WEAK_COMMON: |
| 548 | case DYN_UNDEF * 16 + WEAK_COMMON: |
| 549 | case DYN_WEAK_UNDEF * 16 + WEAK_COMMON: |
| 550 | // A weak common symbol is better than an undefined symbol. |
| 551 | return true; |
| 552 | |
| 553 | case COMMON * 16 + WEAK_COMMON: |
| 554 | case WEAK_COMMON * 16 + WEAK_COMMON: |
| 555 | case DYN_COMMON * 16 + WEAK_COMMON: |
| 556 | case DYN_WEAK_COMMON * 16 + WEAK_COMMON: |
| 557 | // Ignore a weak common symbol in the presence of a real common |
| 558 | // symbol. |
| 559 | return false; |
| 560 | |
| 561 | case DEF * 16 + DYN_COMMON: |
| 562 | case WEAK_DEF * 16 + DYN_COMMON: |
| 563 | case DYN_DEF * 16 + DYN_COMMON: |
| 564 | case DYN_WEAK_DEF * 16 + DYN_COMMON: |
| 565 | // Ignore a dynamic common symbol in the presence of a |
| 566 | // definition. |
| 567 | return false; |
| 568 | |
| 569 | case UNDEF * 16 + DYN_COMMON: |
| 570 | case WEAK_UNDEF * 16 + DYN_COMMON: |
| 571 | case DYN_UNDEF * 16 + DYN_COMMON: |
| 572 | case DYN_WEAK_UNDEF * 16 + DYN_COMMON: |
| 573 | // A dynamic common symbol is a definition of sorts. |
| 574 | return true; |
| 575 | |
| 576 | case COMMON * 16 + DYN_COMMON: |
| 577 | case WEAK_COMMON * 16 + DYN_COMMON: |
| 578 | case DYN_COMMON * 16 + DYN_COMMON: |
| 579 | case DYN_WEAK_COMMON * 16 + DYN_COMMON: |
| 580 | // Set the size to the maximum. |
| 581 | *adjust_common_sizes = true; |
| 582 | return false; |
| 583 | |
| 584 | case DEF * 16 + DYN_WEAK_COMMON: |
| 585 | case WEAK_DEF * 16 + DYN_WEAK_COMMON: |
| 586 | case DYN_DEF * 16 + DYN_WEAK_COMMON: |
| 587 | case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON: |
| 588 | // A common symbol is ignored in the face of a definition. |
| 589 | return false; |
| 590 | |
| 591 | case UNDEF * 16 + DYN_WEAK_COMMON: |
| 592 | case WEAK_UNDEF * 16 + DYN_WEAK_COMMON: |
| 593 | case DYN_UNDEF * 16 + DYN_WEAK_COMMON: |
| 594 | case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON: |
| 595 | // I guess a weak common symbol is better than a definition. |
| 596 | return true; |
| 597 | |
| 598 | case COMMON * 16 + DYN_WEAK_COMMON: |
| 599 | case WEAK_COMMON * 16 + DYN_WEAK_COMMON: |
| 600 | case DYN_COMMON * 16 + DYN_WEAK_COMMON: |
| 601 | case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON: |
| 602 | // Set the size to the maximum. |
| 603 | *adjust_common_sizes = true; |
| 604 | return false; |
| 605 | |
| 606 | default: |
| 607 | gold_unreachable(); |
| 608 | } |
| 609 | } |
| 610 | |
| 611 | // A special case of should_override which is only called for a strong |
| 612 | // defined symbol from a regular object file. This is used when |
| 613 | // defining special symbols. |
| 614 | |
| 615 | bool |
| 616 | Symbol_table::should_override_with_special(const Symbol* to) |
| 617 | { |
| 618 | bool adjust_common_sizes; |
| 619 | unsigned int frombits = global_flag | regular_flag | def_flag; |
| 620 | bool ret = Symbol_table::should_override(to, frombits, NULL, |
| 621 | &adjust_common_sizes); |
| 622 | gold_assert(!adjust_common_sizes); |
| 623 | return ret; |
| 624 | } |
| 625 | |
| 626 | // Override symbol base with a special symbol. |
| 627 | |
| 628 | void |
| 629 | Symbol::override_base_with_special(const Symbol* from) |
| 630 | { |
| 631 | gold_assert(this->name_ == from->name_ || this->has_alias()); |
| 632 | |
| 633 | this->source_ = from->source_; |
| 634 | switch (from->source_) |
| 635 | { |
| 636 | case FROM_OBJECT: |
| 637 | this->u_.from_object = from->u_.from_object; |
| 638 | break; |
| 639 | case IN_OUTPUT_DATA: |
| 640 | this->u_.in_output_data = from->u_.in_output_data; |
| 641 | break; |
| 642 | case IN_OUTPUT_SEGMENT: |
| 643 | this->u_.in_output_segment = from->u_.in_output_segment; |
| 644 | break; |
| 645 | case CONSTANT: |
| 646 | break; |
| 647 | default: |
| 648 | gold_unreachable(); |
| 649 | break; |
| 650 | } |
| 651 | |
| 652 | if (from->version_ != NULL && this->version_ != from->version_) |
| 653 | { |
| 654 | gold_assert(this->version_ == NULL); |
| 655 | this->version_ = from->version_; |
| 656 | } |
| 657 | |
| 658 | this->type_ = from->type_; |
| 659 | this->binding_ = from->binding_; |
| 660 | this->visibility_ = from->visibility_; |
| 661 | this->nonvis_ = from->nonvis_; |
| 662 | |
| 663 | // Special symbols are always considered to be regular symbols. |
| 664 | this->in_reg_ = true; |
| 665 | |
| 666 | if (from->needs_dynsym_entry_) |
| 667 | this->needs_dynsym_entry_ = true; |
| 668 | if (from->needs_dynsym_value_) |
| 669 | this->needs_dynsym_value_ = true; |
| 670 | |
| 671 | // We shouldn't see these flags. If we do, we need to handle them |
| 672 | // somehow. |
| 673 | gold_assert(!from->is_target_special_ || this->is_target_special_); |
| 674 | gold_assert(!from->is_forwarder_); |
| 675 | gold_assert(!from->has_got_offset_); |
| 676 | gold_assert(!from->has_plt_offset_); |
| 677 | gold_assert(!from->has_warning_); |
| 678 | gold_assert(!from->is_copied_from_dynobj_); |
| 679 | } |
| 680 | |
| 681 | // Override a symbol with a special symbol. |
| 682 | |
| 683 | template<int size> |
| 684 | void |
| 685 | Sized_symbol<size>::override_with_special(const Sized_symbol<size>* from) |
| 686 | { |
| 687 | this->override_base_with_special(from); |
| 688 | this->value_ = from->value_; |
| 689 | this->symsize_ = from->symsize_; |
| 690 | } |
| 691 | |
| 692 | // Override TOSYM with the special symbol FROMSYM. This handles all |
| 693 | // aliases of TOSYM. |
| 694 | |
| 695 | template<int size> |
| 696 | void |
| 697 | Symbol_table::override_with_special(Sized_symbol<size>* tosym, |
| 698 | const Sized_symbol<size>* fromsym) |
| 699 | { |
| 700 | tosym->override_with_special(fromsym); |
| 701 | if (tosym->has_alias()) |
| 702 | { |
| 703 | Symbol* sym = this->weak_aliases_[tosym]; |
| 704 | gold_assert(sym != NULL); |
| 705 | Sized_symbol<size>* ssym; |
| 706 | ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym |
| 707 | SELECT_SIZE(size)); |
| 708 | do |
| 709 | { |
| 710 | ssym->override_with_special(fromsym); |
| 711 | sym = this->weak_aliases_[ssym]; |
| 712 | gold_assert(sym != NULL); |
| 713 | ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) ( |
| 714 | sym SELECT_SIZE(size)); |
| 715 | } |
| 716 | while (ssym != tosym); |
| 717 | } |
| 718 | } |
| 719 | |
| 720 | // Instantiate the templates we need. We could use the configure |
| 721 | // script to restrict this to only the ones needed for implemented |
| 722 | // targets. |
| 723 | |
| 724 | #ifdef HAVE_TARGET_32_LITTLE |
| 725 | template |
| 726 | void |
| 727 | Symbol_table::resolve<32, false>( |
| 728 | Sized_symbol<32>* to, |
| 729 | const elfcpp::Sym<32, false>& sym, |
| 730 | const elfcpp::Sym<32, false>& orig_sym, |
| 731 | Object* object, |
| 732 | const char* version); |
| 733 | #endif |
| 734 | |
| 735 | #ifdef HAVE_TARGET_32_BIG |
| 736 | template |
| 737 | void |
| 738 | Symbol_table::resolve<32, true>( |
| 739 | Sized_symbol<32>* to, |
| 740 | const elfcpp::Sym<32, true>& sym, |
| 741 | const elfcpp::Sym<32, true>& orig_sym, |
| 742 | Object* object, |
| 743 | const char* version); |
| 744 | #endif |
| 745 | |
| 746 | #ifdef HAVE_TARGET_64_LITTLE |
| 747 | template |
| 748 | void |
| 749 | Symbol_table::resolve<64, false>( |
| 750 | Sized_symbol<64>* to, |
| 751 | const elfcpp::Sym<64, false>& sym, |
| 752 | const elfcpp::Sym<64, false>& orig_sym, |
| 753 | Object* object, |
| 754 | const char* version); |
| 755 | #endif |
| 756 | |
| 757 | #ifdef HAVE_TARGET_64_BIG |
| 758 | template |
| 759 | void |
| 760 | Symbol_table::resolve<64, true>( |
| 761 | Sized_symbol<64>* to, |
| 762 | const elfcpp::Sym<64, true>& sym, |
| 763 | const elfcpp::Sym<64, true>& orig_sym, |
| 764 | Object* object, |
| 765 | const char* version); |
| 766 | #endif |
| 767 | |
| 768 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) |
| 769 | template |
| 770 | void |
| 771 | Symbol_table::override_with_special<32>(Sized_symbol<32>*, |
| 772 | const Sized_symbol<32>*); |
| 773 | #endif |
| 774 | |
| 775 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) |
| 776 | template |
| 777 | void |
| 778 | Symbol_table::override_with_special<64>(Sized_symbol<64>*, |
| 779 | const Sized_symbol<64>*); |
| 780 | #endif |
| 781 | |
| 782 | } // End namespace gold. |