| 1 | // symtab.h -- the gold symbol table -*- C++ -*- |
| 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 | // Symbol_table |
| 24 | // The symbol table. |
| 25 | |
| 26 | #include <string> |
| 27 | #include <utility> |
| 28 | #include <vector> |
| 29 | |
| 30 | #include "elfcpp.h" |
| 31 | #include "parameters.h" |
| 32 | #include "stringpool.h" |
| 33 | #include "object.h" |
| 34 | |
| 35 | #ifndef GOLD_SYMTAB_H |
| 36 | #define GOLD_SYMTAB_H |
| 37 | |
| 38 | namespace gold |
| 39 | { |
| 40 | |
| 41 | class Object; |
| 42 | class Relobj; |
| 43 | template<int size, bool big_endian> |
| 44 | class Sized_relobj; |
| 45 | class Dynobj; |
| 46 | template<int size, bool big_endian> |
| 47 | class Sized_dynobj; |
| 48 | class Versions; |
| 49 | class Input_objects; |
| 50 | class Output_data; |
| 51 | class Output_section; |
| 52 | class Output_segment; |
| 53 | class Output_file; |
| 54 | class Target; |
| 55 | |
| 56 | // The base class of an entry in the symbol table. The symbol table |
| 57 | // can have a lot of entries, so we don't want this class to big. |
| 58 | // Size dependent fields can be found in the template class |
| 59 | // Sized_symbol. Targets may support their own derived classes. |
| 60 | |
| 61 | class Symbol |
| 62 | { |
| 63 | public: |
| 64 | // Because we want the class to be small, we don't use any virtual |
| 65 | // functions. But because symbols can be defined in different |
| 66 | // places, we need to classify them. This enum is the different |
| 67 | // sources of symbols we support. |
| 68 | enum Source |
| 69 | { |
| 70 | // Symbol defined in a relocatable or dynamic input file--this is |
| 71 | // the most common case. |
| 72 | FROM_OBJECT, |
| 73 | // Symbol defined in an Output_data, a special section created by |
| 74 | // the target. |
| 75 | IN_OUTPUT_DATA, |
| 76 | // Symbol defined in an Output_segment, with no associated |
| 77 | // section. |
| 78 | IN_OUTPUT_SEGMENT, |
| 79 | // Symbol value is constant. |
| 80 | CONSTANT |
| 81 | }; |
| 82 | |
| 83 | // When the source is IN_OUTPUT_SEGMENT, we need to describe what |
| 84 | // the offset means. |
| 85 | enum Segment_offset_base |
| 86 | { |
| 87 | // From the start of the segment. |
| 88 | SEGMENT_START, |
| 89 | // From the end of the segment. |
| 90 | SEGMENT_END, |
| 91 | // From the filesz of the segment--i.e., after the loaded bytes |
| 92 | // but before the bytes which are allocated but zeroed. |
| 93 | SEGMENT_BSS |
| 94 | }; |
| 95 | |
| 96 | // Return the symbol name. |
| 97 | const char* |
| 98 | name() const |
| 99 | { return this->name_; } |
| 100 | |
| 101 | // Return the (ANSI) demangled version of the name, if |
| 102 | // parameters.demangle() is true. Otherwise, return the name. This |
| 103 | // is intended to be used only for logging errors, so it's not |
| 104 | // super-efficient. |
| 105 | std::string |
| 106 | demangled_name() const; |
| 107 | |
| 108 | // Return the symbol version. This will return NULL for an |
| 109 | // unversioned symbol. |
| 110 | const char* |
| 111 | version() const |
| 112 | { return this->version_; } |
| 113 | |
| 114 | // Return the symbol source. |
| 115 | Source |
| 116 | source() const |
| 117 | { return this->source_; } |
| 118 | |
| 119 | // Return the object with which this symbol is associated. |
| 120 | Object* |
| 121 | object() const |
| 122 | { |
| 123 | gold_assert(this->source_ == FROM_OBJECT); |
| 124 | return this->u_.from_object.object; |
| 125 | } |
| 126 | |
| 127 | // Return the index of the section in the input relocatable or |
| 128 | // dynamic object file. |
| 129 | unsigned int |
| 130 | shndx() const |
| 131 | { |
| 132 | gold_assert(this->source_ == FROM_OBJECT); |
| 133 | return this->u_.from_object.shndx; |
| 134 | } |
| 135 | |
| 136 | // Return the output data section with which this symbol is |
| 137 | // associated, if the symbol was specially defined with respect to |
| 138 | // an output data section. |
| 139 | Output_data* |
| 140 | output_data() const |
| 141 | { |
| 142 | gold_assert(this->source_ == IN_OUTPUT_DATA); |
| 143 | return this->u_.in_output_data.output_data; |
| 144 | } |
| 145 | |
| 146 | // If this symbol was defined with respect to an output data |
| 147 | // section, return whether the value is an offset from end. |
| 148 | bool |
| 149 | offset_is_from_end() const |
| 150 | { |
| 151 | gold_assert(this->source_ == IN_OUTPUT_DATA); |
| 152 | return this->u_.in_output_data.offset_is_from_end; |
| 153 | } |
| 154 | |
| 155 | // Return the output segment with which this symbol is associated, |
| 156 | // if the symbol was specially defined with respect to an output |
| 157 | // segment. |
| 158 | Output_segment* |
| 159 | output_segment() const |
| 160 | { |
| 161 | gold_assert(this->source_ == IN_OUTPUT_SEGMENT); |
| 162 | return this->u_.in_output_segment.output_segment; |
| 163 | } |
| 164 | |
| 165 | // If this symbol was defined with respect to an output segment, |
| 166 | // return the offset base. |
| 167 | Segment_offset_base |
| 168 | offset_base() const |
| 169 | { |
| 170 | gold_assert(this->source_ == IN_OUTPUT_SEGMENT); |
| 171 | return this->u_.in_output_segment.offset_base; |
| 172 | } |
| 173 | |
| 174 | // Return the symbol binding. |
| 175 | elfcpp::STB |
| 176 | binding() const |
| 177 | { return this->binding_; } |
| 178 | |
| 179 | // Return the symbol type. |
| 180 | elfcpp::STT |
| 181 | type() const |
| 182 | { return this->type_; } |
| 183 | |
| 184 | // Return the symbol visibility. |
| 185 | elfcpp::STV |
| 186 | visibility() const |
| 187 | { return this->visibility_; } |
| 188 | |
| 189 | // Return the non-visibility part of the st_other field. |
| 190 | unsigned char |
| 191 | nonvis() const |
| 192 | { return this->nonvis_; } |
| 193 | |
| 194 | // Return whether this symbol is a forwarder. This will never be |
| 195 | // true of a symbol found in the hash table, but may be true of |
| 196 | // symbol pointers attached to object files. |
| 197 | bool |
| 198 | is_forwarder() const |
| 199 | { return this->is_forwarder_; } |
| 200 | |
| 201 | // Mark this symbol as a forwarder. |
| 202 | void |
| 203 | set_forwarder() |
| 204 | { this->is_forwarder_ = true; } |
| 205 | |
| 206 | // Return whether this symbol has an alias in the weak aliases table |
| 207 | // in Symbol_table. |
| 208 | bool |
| 209 | has_alias() const |
| 210 | { return this->has_alias_; } |
| 211 | |
| 212 | // Mark this symbol as having an alias. |
| 213 | void |
| 214 | set_has_alias() |
| 215 | { this->has_alias_ = true; } |
| 216 | |
| 217 | // Return whether this symbol needs an entry in the dynamic symbol |
| 218 | // table. |
| 219 | bool |
| 220 | needs_dynsym_entry() const |
| 221 | { |
| 222 | return (this->needs_dynsym_entry_ |
| 223 | || (this->in_reg() && this->in_dyn())); |
| 224 | } |
| 225 | |
| 226 | // Mark this symbol as needing an entry in the dynamic symbol table. |
| 227 | void |
| 228 | set_needs_dynsym_entry() |
| 229 | { this->needs_dynsym_entry_ = true; } |
| 230 | |
| 231 | // Return whether this symbol should be added to the dynamic symbol |
| 232 | // table. |
| 233 | bool |
| 234 | should_add_dynsym_entry() const; |
| 235 | |
| 236 | // Return whether this symbol has been seen in a regular object. |
| 237 | bool |
| 238 | in_reg() const |
| 239 | { return this->in_reg_; } |
| 240 | |
| 241 | // Mark this symbol as having been seen in a regular object. |
| 242 | void |
| 243 | set_in_reg() |
| 244 | { this->in_reg_ = true; } |
| 245 | |
| 246 | // Return whether this symbol has been seen in a dynamic object. |
| 247 | bool |
| 248 | in_dyn() const |
| 249 | { return this->in_dyn_; } |
| 250 | |
| 251 | // Mark this symbol as having been seen in a dynamic object. |
| 252 | void |
| 253 | set_in_dyn() |
| 254 | { this->in_dyn_ = true; } |
| 255 | |
| 256 | // Return the index of this symbol in the output file symbol table. |
| 257 | // A value of -1U means that this symbol is not going into the |
| 258 | // output file. This starts out as zero, and is set to a non-zero |
| 259 | // value by Symbol_table::finalize. It is an error to ask for the |
| 260 | // symbol table index before it has been set. |
| 261 | unsigned int |
| 262 | symtab_index() const |
| 263 | { |
| 264 | gold_assert(this->symtab_index_ != 0); |
| 265 | return this->symtab_index_; |
| 266 | } |
| 267 | |
| 268 | // Set the index of the symbol in the output file symbol table. |
| 269 | void |
| 270 | set_symtab_index(unsigned int index) |
| 271 | { |
| 272 | gold_assert(index != 0); |
| 273 | this->symtab_index_ = index; |
| 274 | } |
| 275 | |
| 276 | // Return whether this symbol already has an index in the output |
| 277 | // file symbol table. |
| 278 | bool |
| 279 | has_symtab_index() const |
| 280 | { return this->symtab_index_ != 0; } |
| 281 | |
| 282 | // Return the index of this symbol in the dynamic symbol table. A |
| 283 | // value of -1U means that this symbol is not going into the dynamic |
| 284 | // symbol table. This starts out as zero, and is set to a non-zero |
| 285 | // during Layout::finalize. It is an error to ask for the dynamic |
| 286 | // symbol table index before it has been set. |
| 287 | unsigned int |
| 288 | dynsym_index() const |
| 289 | { |
| 290 | gold_assert(this->dynsym_index_ != 0); |
| 291 | return this->dynsym_index_; |
| 292 | } |
| 293 | |
| 294 | // Set the index of the symbol in the dynamic symbol table. |
| 295 | void |
| 296 | set_dynsym_index(unsigned int index) |
| 297 | { |
| 298 | gold_assert(index != 0); |
| 299 | this->dynsym_index_ = index; |
| 300 | } |
| 301 | |
| 302 | // Return whether this symbol already has an index in the dynamic |
| 303 | // symbol table. |
| 304 | bool |
| 305 | has_dynsym_index() const |
| 306 | { return this->dynsym_index_ != 0; } |
| 307 | |
| 308 | // Return whether this symbol has an entry in the GOT section. |
| 309 | // For a TLS symbol, this GOT entry will hold its tp-relative offset. |
| 310 | bool |
| 311 | has_got_offset() const |
| 312 | { return this->has_got_offset_; } |
| 313 | |
| 314 | // Return the offset into the GOT section of this symbol. |
| 315 | unsigned int |
| 316 | got_offset() const |
| 317 | { |
| 318 | gold_assert(this->has_got_offset()); |
| 319 | return this->got_offset_; |
| 320 | } |
| 321 | |
| 322 | // Set the GOT offset of this symbol. |
| 323 | void |
| 324 | set_got_offset(unsigned int got_offset) |
| 325 | { |
| 326 | this->has_got_offset_ = true; |
| 327 | this->got_offset_ = got_offset; |
| 328 | } |
| 329 | |
| 330 | // Return whether this TLS symbol has an entry in the GOT section for |
| 331 | // its module index or, if NEED_PAIR is true, has a pair of entries |
| 332 | // for its module index and dtv-relative offset. |
| 333 | bool |
| 334 | has_tls_got_offset(bool need_pair) const |
| 335 | { |
| 336 | return (this->has_tls_mod_got_offset_ |
| 337 | && (!need_pair || this->has_tls_pair_got_offset_)); |
| 338 | } |
| 339 | |
| 340 | // Return the offset into the GOT section for this symbol's TLS module |
| 341 | // index or, if NEED_PAIR is true, for the pair of entries for the |
| 342 | // module index and dtv-relative offset. |
| 343 | unsigned int |
| 344 | tls_got_offset(bool need_pair) const |
| 345 | { |
| 346 | gold_assert(this->has_tls_got_offset(need_pair)); |
| 347 | return this->tls_mod_got_offset_; |
| 348 | } |
| 349 | |
| 350 | // Set the GOT offset of this symbol. |
| 351 | void |
| 352 | set_tls_got_offset(unsigned int got_offset, bool have_pair) |
| 353 | { |
| 354 | this->has_tls_mod_got_offset_ = true; |
| 355 | this->has_tls_pair_got_offset_ = have_pair; |
| 356 | this->tls_mod_got_offset_ = got_offset; |
| 357 | } |
| 358 | |
| 359 | // Return whether this symbol has an entry in the PLT section. |
| 360 | bool |
| 361 | has_plt_offset() const |
| 362 | { return this->has_plt_offset_; } |
| 363 | |
| 364 | // Return the offset into the PLT section of this symbol. |
| 365 | unsigned int |
| 366 | plt_offset() const |
| 367 | { |
| 368 | gold_assert(this->has_plt_offset()); |
| 369 | return this->plt_offset_; |
| 370 | } |
| 371 | |
| 372 | // Set the PLT offset of this symbol. |
| 373 | void |
| 374 | set_plt_offset(unsigned int plt_offset) |
| 375 | { |
| 376 | this->has_plt_offset_ = true; |
| 377 | this->plt_offset_ = plt_offset; |
| 378 | } |
| 379 | |
| 380 | // Return whether this dynamic symbol needs a special value in the |
| 381 | // dynamic symbol table. |
| 382 | bool |
| 383 | needs_dynsym_value() const |
| 384 | { return this->needs_dynsym_value_; } |
| 385 | |
| 386 | // Set that this dynamic symbol needs a special value in the dynamic |
| 387 | // symbol table. |
| 388 | void |
| 389 | set_needs_dynsym_value() |
| 390 | { |
| 391 | gold_assert(this->object()->is_dynamic()); |
| 392 | this->needs_dynsym_value_ = true; |
| 393 | } |
| 394 | |
| 395 | // Return true if the final value of this symbol is known at link |
| 396 | // time. |
| 397 | bool |
| 398 | final_value_is_known() const; |
| 399 | |
| 400 | // Return whether this is a defined symbol (not undefined or |
| 401 | // common). |
| 402 | bool |
| 403 | is_defined() const |
| 404 | { |
| 405 | return (this->source_ != FROM_OBJECT |
| 406 | || (this->shndx() != elfcpp::SHN_UNDEF |
| 407 | && this->shndx() != elfcpp::SHN_COMMON)); |
| 408 | } |
| 409 | |
| 410 | // Return true if this symbol is from a dynamic object. |
| 411 | bool |
| 412 | is_from_dynobj() const |
| 413 | { |
| 414 | return this->source_ == FROM_OBJECT && this->object()->is_dynamic(); |
| 415 | } |
| 416 | |
| 417 | // Return whether this is an undefined symbol. |
| 418 | bool |
| 419 | is_undefined() const |
| 420 | { |
| 421 | return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF; |
| 422 | } |
| 423 | |
| 424 | // Return whether this is a common symbol. |
| 425 | bool |
| 426 | is_common() const |
| 427 | { |
| 428 | return (this->source_ == FROM_OBJECT |
| 429 | && (this->shndx() == elfcpp::SHN_COMMON |
| 430 | || this->type_ == elfcpp::STT_COMMON)); |
| 431 | } |
| 432 | |
| 433 | // Return whether this symbol can be seen outside this object. |
| 434 | bool |
| 435 | is_externally_visible() const |
| 436 | { |
| 437 | return (this->visibility_ == elfcpp::STV_DEFAULT |
| 438 | || this->visibility_ == elfcpp::STV_PROTECTED); |
| 439 | } |
| 440 | |
| 441 | // Return true if this symbol can be preempted by a definition in |
| 442 | // another link unit. |
| 443 | bool |
| 444 | is_preemptible() const |
| 445 | { |
| 446 | // It doesn't make sense to ask whether a symbol defined in |
| 447 | // another object is preemptible. |
| 448 | gold_assert(!this->is_from_dynobj()); |
| 449 | |
| 450 | return (this->visibility_ != elfcpp::STV_INTERNAL |
| 451 | && this->visibility_ != elfcpp::STV_HIDDEN |
| 452 | && this->visibility_ != elfcpp::STV_PROTECTED |
| 453 | && parameters->output_is_shared() |
| 454 | && !parameters->symbolic()); |
| 455 | } |
| 456 | |
| 457 | // Return true if this symbol is a function that needs a PLT entry. |
| 458 | // If the symbol is defined in a dynamic object or if it is subject |
| 459 | // to pre-emption, we need to make a PLT entry. |
| 460 | bool |
| 461 | needs_plt_entry() const |
| 462 | { |
| 463 | return (this->type() == elfcpp::STT_FUNC |
| 464 | && (this->is_from_dynobj() || this->is_preemptible())); |
| 465 | } |
| 466 | |
| 467 | // Given a direct absolute or pc-relative static relocation against |
| 468 | // the global symbol, this function returns whether a dynamic relocation |
| 469 | // is needed. |
| 470 | |
| 471 | bool |
| 472 | needs_dynamic_reloc(bool is_absolute_ref, bool is_function_call) const |
| 473 | { |
| 474 | // An absolute reference within a position-independent output file |
| 475 | // will need a dynamic relocaion. |
| 476 | if (is_absolute_ref && parameters->output_is_position_independent()) |
| 477 | return true; |
| 478 | |
| 479 | // A function call that can branch to a local PLT entry does not need |
| 480 | // a dynamic relocation. |
| 481 | if (is_function_call && this->has_plt_offset()) |
| 482 | return false; |
| 483 | |
| 484 | // A reference to any PLT entry in a non-position-independent executable |
| 485 | // does not need a dynamic relocation. |
| 486 | if (!parameters->output_is_position_independent() |
| 487 | && this->has_plt_offset()) |
| 488 | return false; |
| 489 | |
| 490 | // A reference to a symbol defined in a dynamic object or to a |
| 491 | // symbol that is preemptible will need a dynamic relocation. |
| 492 | if (this->is_from_dynobj() || this->is_preemptible()) |
| 493 | return true; |
| 494 | |
| 495 | // For all other cases, return FALSE. |
| 496 | return false; |
| 497 | } |
| 498 | |
| 499 | // Given a direct absolute static relocation against |
| 500 | // the global symbol, where a dynamic relocation is needed, this |
| 501 | // function returns whether a relative dynamic relocation can be used. |
| 502 | // The caller must determine separately whether the static relocation |
| 503 | // is compatible with a relative relocation. |
| 504 | |
| 505 | bool |
| 506 | can_use_relative_reloc(bool is_function_call) const |
| 507 | { |
| 508 | // A function call that can branch to a local PLT entry can |
| 509 | // use a RELATIVE relocation. |
| 510 | if (is_function_call && this->has_plt_offset()) |
| 511 | return true; |
| 512 | |
| 513 | // A reference to a symbol defined in a dynamic object or to a |
| 514 | // symbol that is preemptible can not use a RELATIVE relocaiton. |
| 515 | if (this->is_from_dynobj() || this->is_preemptible()) |
| 516 | return false; |
| 517 | |
| 518 | // For all other cases, return TRUE. |
| 519 | return true; |
| 520 | } |
| 521 | |
| 522 | // Return whether there should be a warning for references to this |
| 523 | // symbol. |
| 524 | bool |
| 525 | has_warning() const |
| 526 | { return this->has_warning_; } |
| 527 | |
| 528 | // Mark this symbol as having a warning. |
| 529 | void |
| 530 | set_has_warning() |
| 531 | { this->has_warning_ = true; } |
| 532 | |
| 533 | // Return whether this symbol is defined by a COPY reloc from a |
| 534 | // dynamic object. |
| 535 | bool |
| 536 | is_copied_from_dynobj() const |
| 537 | { return this->is_copied_from_dynobj_; } |
| 538 | |
| 539 | // Mark this symbol as defined by a COPY reloc. |
| 540 | void |
| 541 | set_is_copied_from_dynobj() |
| 542 | { this->is_copied_from_dynobj_ = true; } |
| 543 | |
| 544 | // Mark this symbol as needing its value written to the GOT even when |
| 545 | // the value is subject to dynamic relocation (e.g., when the target |
| 546 | // uses a RELATIVE relocation for the GOT entry). |
| 547 | void |
| 548 | set_needs_value_in_got() |
| 549 | { this->needs_value_in_got_ = true; } |
| 550 | |
| 551 | // Return whether this symbol needs its value written to the GOT even |
| 552 | // when the value is subject to dynamic relocation. |
| 553 | bool |
| 554 | needs_value_in_got() const |
| 555 | { return this->needs_value_in_got_; } |
| 556 | |
| 557 | protected: |
| 558 | // Instances of this class should always be created at a specific |
| 559 | // size. |
| 560 | Symbol() |
| 561 | { memset(this, 0, sizeof *this); } |
| 562 | |
| 563 | // Initialize the general fields. |
| 564 | void |
| 565 | init_fields(const char* name, const char* version, |
| 566 | elfcpp::STT type, elfcpp::STB binding, |
| 567 | elfcpp::STV visibility, unsigned char nonvis); |
| 568 | |
| 569 | // Initialize fields from an ELF symbol in OBJECT. |
| 570 | template<int size, bool big_endian> |
| 571 | void |
| 572 | init_base(const char *name, const char* version, Object* object, |
| 573 | const elfcpp::Sym<size, big_endian>&); |
| 574 | |
| 575 | // Initialize fields for an Output_data. |
| 576 | void |
| 577 | init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB, |
| 578 | elfcpp::STV, unsigned char nonvis, bool offset_is_from_end); |
| 579 | |
| 580 | // Initialize fields for an Output_segment. |
| 581 | void |
| 582 | init_base(const char* name, Output_segment* os, elfcpp::STT type, |
| 583 | elfcpp::STB binding, elfcpp::STV visibility, |
| 584 | unsigned char nonvis, Segment_offset_base offset_base); |
| 585 | |
| 586 | // Initialize fields for a constant. |
| 587 | void |
| 588 | init_base(const char* name, elfcpp::STT type, elfcpp::STB binding, |
| 589 | elfcpp::STV visibility, unsigned char nonvis); |
| 590 | |
| 591 | // Override existing symbol. |
| 592 | template<int size, bool big_endian> |
| 593 | void |
| 594 | override_base(const elfcpp::Sym<size, big_endian>&, Object* object, |
| 595 | const char* version); |
| 596 | |
| 597 | // Override existing symbol with a special symbol. |
| 598 | void |
| 599 | override_base_with_special(const Symbol* from); |
| 600 | |
| 601 | // Allocate a common symbol by giving it a location in the output |
| 602 | // file. |
| 603 | void |
| 604 | allocate_base_common(Output_data*); |
| 605 | |
| 606 | private: |
| 607 | Symbol(const Symbol&); |
| 608 | Symbol& operator=(const Symbol&); |
| 609 | |
| 610 | // Symbol name (expected to point into a Stringpool). |
| 611 | const char* name_; |
| 612 | // Symbol version (expected to point into a Stringpool). This may |
| 613 | // be NULL. |
| 614 | const char* version_; |
| 615 | |
| 616 | union |
| 617 | { |
| 618 | // This struct is used if SOURCE_ == FROM_OBJECT. |
| 619 | struct |
| 620 | { |
| 621 | // Object in which symbol is defined, or in which it was first |
| 622 | // seen. |
| 623 | Object* object; |
| 624 | // Section number in object_ in which symbol is defined. |
| 625 | unsigned int shndx; |
| 626 | } from_object; |
| 627 | |
| 628 | // This struct is used if SOURCE_ == IN_OUTPUT_DATA. |
| 629 | struct |
| 630 | { |
| 631 | // Output_data in which symbol is defined. Before |
| 632 | // Layout::finalize the symbol's value is an offset within the |
| 633 | // Output_data. |
| 634 | Output_data* output_data; |
| 635 | // True if the offset is from the end, false if the offset is |
| 636 | // from the beginning. |
| 637 | bool offset_is_from_end; |
| 638 | } in_output_data; |
| 639 | |
| 640 | // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT. |
| 641 | struct |
| 642 | { |
| 643 | // Output_segment in which the symbol is defined. Before |
| 644 | // Layout::finalize the symbol's value is an offset. |
| 645 | Output_segment* output_segment; |
| 646 | // The base to use for the offset before Layout::finalize. |
| 647 | Segment_offset_base offset_base; |
| 648 | } in_output_segment; |
| 649 | } u_; |
| 650 | |
| 651 | // The index of this symbol in the output file. If the symbol is |
| 652 | // not going into the output file, this value is -1U. This field |
| 653 | // starts as always holding zero. It is set to a non-zero value by |
| 654 | // Symbol_table::finalize. |
| 655 | unsigned int symtab_index_; |
| 656 | |
| 657 | // The index of this symbol in the dynamic symbol table. If the |
| 658 | // symbol is not going into the dynamic symbol table, this value is |
| 659 | // -1U. This field starts as always holding zero. It is set to a |
| 660 | // non-zero value during Layout::finalize. |
| 661 | unsigned int dynsym_index_; |
| 662 | |
| 663 | // If this symbol has an entry in the GOT section (has_got_offset_ |
| 664 | // is true), this is the offset from the start of the GOT section. |
| 665 | // For a TLS symbol, if has_tls_tpoff_got_offset_ is true, this |
| 666 | // serves as the GOT offset for the GOT entry that holds its |
| 667 | // TP-relative offset. |
| 668 | unsigned int got_offset_; |
| 669 | |
| 670 | // If this is a TLS symbol and has an entry in the GOT section |
| 671 | // for a module index or a pair of entries (module index, |
| 672 | // dtv-relative offset), these are the offsets from the start |
| 673 | // of the GOT section. |
| 674 | unsigned int tls_mod_got_offset_; |
| 675 | unsigned int tls_pair_got_offset_; |
| 676 | |
| 677 | // If this symbol has an entry in the PLT section (has_plt_offset_ |
| 678 | // is true), then this is the offset from the start of the PLT |
| 679 | // section. |
| 680 | unsigned int plt_offset_; |
| 681 | |
| 682 | // Symbol type. |
| 683 | elfcpp::STT type_ : 4; |
| 684 | // Symbol binding. |
| 685 | elfcpp::STB binding_ : 4; |
| 686 | // Symbol visibility. |
| 687 | elfcpp::STV visibility_ : 2; |
| 688 | // Rest of symbol st_other field. |
| 689 | unsigned int nonvis_ : 6; |
| 690 | // The type of symbol. |
| 691 | Source source_ : 3; |
| 692 | // True if this symbol always requires special target-specific |
| 693 | // handling. |
| 694 | bool is_target_special_ : 1; |
| 695 | // True if this is the default version of the symbol. |
| 696 | bool is_def_ : 1; |
| 697 | // True if this symbol really forwards to another symbol. This is |
| 698 | // used when we discover after the fact that two different entries |
| 699 | // in the hash table really refer to the same symbol. This will |
| 700 | // never be set for a symbol found in the hash table, but may be set |
| 701 | // for a symbol found in the list of symbols attached to an Object. |
| 702 | // It forwards to the symbol found in the forwarders_ map of |
| 703 | // Symbol_table. |
| 704 | bool is_forwarder_ : 1; |
| 705 | // True if the symbol has an alias in the weak_aliases table in |
| 706 | // Symbol_table. |
| 707 | bool has_alias_ : 1; |
| 708 | // True if this symbol needs to be in the dynamic symbol table. |
| 709 | bool needs_dynsym_entry_ : 1; |
| 710 | // True if we've seen this symbol in a regular object. |
| 711 | bool in_reg_ : 1; |
| 712 | // True if we've seen this symbol in a dynamic object. |
| 713 | bool in_dyn_ : 1; |
| 714 | // True if the symbol has an entry in the GOT section. |
| 715 | // For a TLS symbol, this GOT entry will hold its tp-relative offset. |
| 716 | bool has_got_offset_ : 1; |
| 717 | // True if the symbol has an entry in the GOT section for its |
| 718 | // module index. |
| 719 | bool has_tls_mod_got_offset_ : 1; |
| 720 | // True if the symbol has a pair of entries in the GOT section for its |
| 721 | // module index and dtv-relative offset. |
| 722 | bool has_tls_pair_got_offset_ : 1; |
| 723 | // True if the symbol has an entry in the PLT section. |
| 724 | bool has_plt_offset_ : 1; |
| 725 | // True if this is a dynamic symbol which needs a special value in |
| 726 | // the dynamic symbol table. |
| 727 | bool needs_dynsym_value_ : 1; |
| 728 | // True if there is a warning for this symbol. |
| 729 | bool has_warning_ : 1; |
| 730 | // True if we are using a COPY reloc for this symbol, so that the |
| 731 | // real definition lives in a dynamic object. |
| 732 | bool is_copied_from_dynobj_ : 1; |
| 733 | // True if the static value should be written to the GOT even |
| 734 | // when the final value is subject to dynamic relocation. |
| 735 | bool needs_value_in_got_ : 1; |
| 736 | }; |
| 737 | |
| 738 | // The parts of a symbol which are size specific. Using a template |
| 739 | // derived class like this helps us use less space on a 32-bit system. |
| 740 | |
| 741 | template<int size> |
| 742 | class Sized_symbol : public Symbol |
| 743 | { |
| 744 | public: |
| 745 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type; |
| 746 | typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type; |
| 747 | |
| 748 | Sized_symbol() |
| 749 | { } |
| 750 | |
| 751 | // Initialize fields from an ELF symbol in OBJECT. |
| 752 | template<bool big_endian> |
| 753 | void |
| 754 | init(const char *name, const char* version, Object* object, |
| 755 | const elfcpp::Sym<size, big_endian>&); |
| 756 | |
| 757 | // Initialize fields for an Output_data. |
| 758 | void |
| 759 | init(const char* name, Output_data*, Value_type value, Size_type symsize, |
| 760 | elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis, |
| 761 | bool offset_is_from_end); |
| 762 | |
| 763 | // Initialize fields for an Output_segment. |
| 764 | void |
| 765 | init(const char* name, Output_segment*, Value_type value, Size_type symsize, |
| 766 | elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis, |
| 767 | Segment_offset_base offset_base); |
| 768 | |
| 769 | // Initialize fields for a constant. |
| 770 | void |
| 771 | init(const char* name, Value_type value, Size_type symsize, |
| 772 | elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis); |
| 773 | |
| 774 | // Override existing symbol. |
| 775 | template<bool big_endian> |
| 776 | void |
| 777 | override(const elfcpp::Sym<size, big_endian>&, Object* object, |
| 778 | const char* version); |
| 779 | |
| 780 | // Override existing symbol with a special symbol. |
| 781 | void |
| 782 | override_with_special(const Sized_symbol<size>*); |
| 783 | |
| 784 | // Return the symbol's value. |
| 785 | Value_type |
| 786 | value() const |
| 787 | { return this->value_; } |
| 788 | |
| 789 | // Return the symbol's size (we can't call this 'size' because that |
| 790 | // is a template parameter). |
| 791 | Size_type |
| 792 | symsize() const |
| 793 | { return this->symsize_; } |
| 794 | |
| 795 | // Set the symbol size. This is used when resolving common symbols. |
| 796 | void |
| 797 | set_symsize(Size_type symsize) |
| 798 | { this->symsize_ = symsize; } |
| 799 | |
| 800 | // Set the symbol value. This is called when we store the final |
| 801 | // values of the symbols into the symbol table. |
| 802 | void |
| 803 | set_value(Value_type value) |
| 804 | { this->value_ = value; } |
| 805 | |
| 806 | // Allocate a common symbol by giving it a location in the output |
| 807 | // file. |
| 808 | void |
| 809 | allocate_common(Output_data*, Value_type value); |
| 810 | |
| 811 | private: |
| 812 | Sized_symbol(const Sized_symbol&); |
| 813 | Sized_symbol& operator=(const Sized_symbol&); |
| 814 | |
| 815 | // Symbol value. Before Layout::finalize this is the offset in the |
| 816 | // input section. This is set to the final value during |
| 817 | // Layout::finalize. |
| 818 | Value_type value_; |
| 819 | // Symbol size. |
| 820 | Size_type symsize_; |
| 821 | }; |
| 822 | |
| 823 | // A struct describing a symbol defined by the linker, where the value |
| 824 | // of the symbol is defined based on an output section. This is used |
| 825 | // for symbols defined by the linker, like "_init_array_start". |
| 826 | |
| 827 | struct Define_symbol_in_section |
| 828 | { |
| 829 | // The symbol name. |
| 830 | const char* name; |
| 831 | // The name of the output section with which this symbol should be |
| 832 | // associated. If there is no output section with that name, the |
| 833 | // symbol will be defined as zero. |
| 834 | const char* output_section; |
| 835 | // The offset of the symbol within the output section. This is an |
| 836 | // offset from the start of the output section, unless start_at_end |
| 837 | // is true, in which case this is an offset from the end of the |
| 838 | // output section. |
| 839 | uint64_t value; |
| 840 | // The size of the symbol. |
| 841 | uint64_t size; |
| 842 | // The symbol type. |
| 843 | elfcpp::STT type; |
| 844 | // The symbol binding. |
| 845 | elfcpp::STB binding; |
| 846 | // The symbol visibility. |
| 847 | elfcpp::STV visibility; |
| 848 | // The rest of the st_other field. |
| 849 | unsigned char nonvis; |
| 850 | // If true, the value field is an offset from the end of the output |
| 851 | // section. |
| 852 | bool offset_is_from_end; |
| 853 | // If true, this symbol is defined only if we see a reference to it. |
| 854 | bool only_if_ref; |
| 855 | }; |
| 856 | |
| 857 | // A struct describing a symbol defined by the linker, where the value |
| 858 | // of the symbol is defined based on a segment. This is used for |
| 859 | // symbols defined by the linker, like "_end". We describe the |
| 860 | // segment with which the symbol should be associated by its |
| 861 | // characteristics. If no segment meets these characteristics, the |
| 862 | // symbol will be defined as zero. If there is more than one segment |
| 863 | // which meets these characteristics, we will use the first one. |
| 864 | |
| 865 | struct Define_symbol_in_segment |
| 866 | { |
| 867 | // The symbol name. |
| 868 | const char* name; |
| 869 | // The segment type where the symbol should be defined, typically |
| 870 | // PT_LOAD. |
| 871 | elfcpp::PT segment_type; |
| 872 | // Bitmask of segment flags which must be set. |
| 873 | elfcpp::PF segment_flags_set; |
| 874 | // Bitmask of segment flags which must be clear. |
| 875 | elfcpp::PF segment_flags_clear; |
| 876 | // The offset of the symbol within the segment. The offset is |
| 877 | // calculated from the position set by offset_base. |
| 878 | uint64_t value; |
| 879 | // The size of the symbol. |
| 880 | uint64_t size; |
| 881 | // The symbol type. |
| 882 | elfcpp::STT type; |
| 883 | // The symbol binding. |
| 884 | elfcpp::STB binding; |
| 885 | // The symbol visibility. |
| 886 | elfcpp::STV visibility; |
| 887 | // The rest of the st_other field. |
| 888 | unsigned char nonvis; |
| 889 | // The base from which we compute the offset. |
| 890 | Symbol::Segment_offset_base offset_base; |
| 891 | // If true, this symbol is defined only if we see a reference to it. |
| 892 | bool only_if_ref; |
| 893 | }; |
| 894 | |
| 895 | // This class manages warnings. Warnings are a GNU extension. When |
| 896 | // we see a section named .gnu.warning.SYM in an object file, and if |
| 897 | // we wind using the definition of SYM from that object file, then we |
| 898 | // will issue a warning for any relocation against SYM from a |
| 899 | // different object file. The text of the warning is the contents of |
| 900 | // the section. This is not precisely the definition used by the old |
| 901 | // GNU linker; the old GNU linker treated an occurrence of |
| 902 | // .gnu.warning.SYM as defining a warning symbol. A warning symbol |
| 903 | // would trigger a warning on any reference. However, it was |
| 904 | // inconsistent in that a warning in a dynamic object only triggered |
| 905 | // if there was no definition in a regular object. This linker is |
| 906 | // different in that we only issue a warning if we use the symbol |
| 907 | // definition from the same object file as the warning section. |
| 908 | |
| 909 | class Warnings |
| 910 | { |
| 911 | public: |
| 912 | Warnings() |
| 913 | : warnings_() |
| 914 | { } |
| 915 | |
| 916 | // Add a warning for symbol NAME in section SHNDX in object OBJ. |
| 917 | void |
| 918 | add_warning(Symbol_table* symtab, const char* name, Object* obj, |
| 919 | unsigned int shndx); |
| 920 | |
| 921 | // For each symbol for which we should give a warning, make a note |
| 922 | // on the symbol. |
| 923 | void |
| 924 | note_warnings(Symbol_table* symtab); |
| 925 | |
| 926 | // Issue a warning for a reference to SYM at RELINFO's location. |
| 927 | template<int size, bool big_endian> |
| 928 | void |
| 929 | issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*, |
| 930 | size_t relnum, off_t reloffset) const; |
| 931 | |
| 932 | private: |
| 933 | Warnings(const Warnings&); |
| 934 | Warnings& operator=(const Warnings&); |
| 935 | |
| 936 | // What we need to know to get the warning text. |
| 937 | struct Warning_location |
| 938 | { |
| 939 | // The object the warning is in. |
| 940 | Object* object; |
| 941 | // The index of the warning section. |
| 942 | unsigned int shndx; |
| 943 | // The warning text if we have already loaded it. |
| 944 | std::string text; |
| 945 | |
| 946 | Warning_location() |
| 947 | : object(NULL), shndx(0), text() |
| 948 | { } |
| 949 | |
| 950 | void |
| 951 | set(Object* o, unsigned int s) |
| 952 | { |
| 953 | this->object = o; |
| 954 | this->shndx = s; |
| 955 | } |
| 956 | |
| 957 | void |
| 958 | set_text(const char* t, off_t l) |
| 959 | { this->text.assign(t, l); } |
| 960 | }; |
| 961 | |
| 962 | // A mapping from warning symbol names (canonicalized in |
| 963 | // Symbol_table's namepool_ field) to warning information. |
| 964 | typedef Unordered_map<const char*, Warning_location> Warning_table; |
| 965 | |
| 966 | Warning_table warnings_; |
| 967 | }; |
| 968 | |
| 969 | // The main linker symbol table. |
| 970 | |
| 971 | class Symbol_table |
| 972 | { |
| 973 | public: |
| 974 | Symbol_table(); |
| 975 | |
| 976 | ~Symbol_table(); |
| 977 | |
| 978 | // Add COUNT external symbols from the relocatable object RELOBJ to |
| 979 | // the symbol table. SYMS is the symbols, SYM_NAMES is their names, |
| 980 | // SYM_NAME_SIZE is the size of SYM_NAMES. This sets SYMPOINTERS to |
| 981 | // point to the symbols in the symbol table. |
| 982 | template<int size, bool big_endian> |
| 983 | void |
| 984 | add_from_relobj(Sized_relobj<size, big_endian>* relobj, |
| 985 | const unsigned char* syms, size_t count, |
| 986 | const char* sym_names, size_t sym_name_size, |
| 987 | typename Sized_relobj<size, big_endian>::Symbols*); |
| 988 | |
| 989 | // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the |
| 990 | // symbol table. SYMS is the symbols. SYM_NAMES is their names. |
| 991 | // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are |
| 992 | // symbol version data. |
| 993 | template<int size, bool big_endian> |
| 994 | void |
| 995 | add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj, |
| 996 | const unsigned char* syms, size_t count, |
| 997 | const char* sym_names, size_t sym_name_size, |
| 998 | const unsigned char* versym, size_t versym_size, |
| 999 | const std::vector<const char*>*); |
| 1000 | |
| 1001 | // Define a special symbol based on an Output_data. It is a |
| 1002 | // multiple definition error if this symbol is already defined. |
| 1003 | Symbol* |
| 1004 | define_in_output_data(const Target*, const char* name, const char* version, |
| 1005 | Output_data*, uint64_t value, uint64_t symsize, |
| 1006 | elfcpp::STT type, elfcpp::STB binding, |
| 1007 | elfcpp::STV visibility, unsigned char nonvis, |
| 1008 | bool offset_is_from_end, bool only_if_ref); |
| 1009 | |
| 1010 | // Define a special symbol based on an Output_segment. It is a |
| 1011 | // multiple definition error if this symbol is already defined. |
| 1012 | Symbol* |
| 1013 | define_in_output_segment(const Target*, const char* name, |
| 1014 | const char* version, Output_segment*, |
| 1015 | uint64_t value, uint64_t symsize, |
| 1016 | elfcpp::STT type, elfcpp::STB binding, |
| 1017 | elfcpp::STV visibility, unsigned char nonvis, |
| 1018 | Symbol::Segment_offset_base, bool only_if_ref); |
| 1019 | |
| 1020 | // Define a special symbol with a constant value. It is a multiple |
| 1021 | // definition error if this symbol is already defined. |
| 1022 | Symbol* |
| 1023 | define_as_constant(const Target*, const char* name, const char* version, |
| 1024 | uint64_t value, uint64_t symsize, elfcpp::STT type, |
| 1025 | elfcpp::STB binding, elfcpp::STV visibility, |
| 1026 | unsigned char nonvis, bool only_if_ref); |
| 1027 | |
| 1028 | // Define a set of symbols in output sections. |
| 1029 | void |
| 1030 | define_symbols(const Layout*, const Target*, int count, |
| 1031 | const Define_symbol_in_section*); |
| 1032 | |
| 1033 | // Define a set of symbols in output segments. |
| 1034 | void |
| 1035 | define_symbols(const Layout*, const Target*, int count, |
| 1036 | const Define_symbol_in_segment*); |
| 1037 | |
| 1038 | // Define SYM using a COPY reloc. POSD is the Output_data where the |
| 1039 | // symbol should be defined--typically a .dyn.bss section. VALUE is |
| 1040 | // the offset within POSD. |
| 1041 | template<int size> |
| 1042 | void |
| 1043 | define_with_copy_reloc(const Target*, Sized_symbol<size>* sym, |
| 1044 | Output_data* posd, uint64_t value); |
| 1045 | |
| 1046 | // Look up a symbol. |
| 1047 | Symbol* |
| 1048 | lookup(const char*, const char* version = NULL) const; |
| 1049 | |
| 1050 | // Return the real symbol associated with the forwarder symbol FROM. |
| 1051 | Symbol* |
| 1052 | resolve_forwards(const Symbol* from) const; |
| 1053 | |
| 1054 | // Return the sized version of a symbol in this table. |
| 1055 | template<int size> |
| 1056 | Sized_symbol<size>* |
| 1057 | get_sized_symbol(Symbol* ACCEPT_SIZE) const; |
| 1058 | |
| 1059 | template<int size> |
| 1060 | const Sized_symbol<size>* |
| 1061 | get_sized_symbol(const Symbol* ACCEPT_SIZE) const; |
| 1062 | |
| 1063 | // Return the count of undefined symbols seen. |
| 1064 | int |
| 1065 | saw_undefined() const |
| 1066 | { return this->saw_undefined_; } |
| 1067 | |
| 1068 | // Allocate the common symbols |
| 1069 | void |
| 1070 | allocate_commons(const General_options&, Layout*); |
| 1071 | |
| 1072 | // Add a warning for symbol NAME in section SHNDX in object OBJ. |
| 1073 | void |
| 1074 | add_warning(const char* name, Object* obj, unsigned int shndx) |
| 1075 | { this->warnings_.add_warning(this, name, obj, shndx); } |
| 1076 | |
| 1077 | // Canonicalize a symbol name for use in the hash table. |
| 1078 | const char* |
| 1079 | canonicalize_name(const char* name) |
| 1080 | { return this->namepool_.add(name, true, NULL); } |
| 1081 | |
| 1082 | // Possibly issue a warning for a reference to SYM at LOCATION which |
| 1083 | // is in OBJ. |
| 1084 | template<int size, bool big_endian> |
| 1085 | void |
| 1086 | issue_warning(const Symbol* sym, |
| 1087 | const Relocate_info<size, big_endian>* relinfo, |
| 1088 | size_t relnum, off_t reloffset) const |
| 1089 | { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); } |
| 1090 | |
| 1091 | // Check candidate_odr_violations_ to find symbols with the same name |
| 1092 | // but apparently different definitions (different source-file/line-no). |
| 1093 | void |
| 1094 | detect_odr_violations(const char* output_file_name) const; |
| 1095 | |
| 1096 | // SYM is defined using a COPY reloc. Return the dynamic object |
| 1097 | // where the original definition was found. |
| 1098 | Dynobj* |
| 1099 | get_copy_source(const Symbol* sym) const; |
| 1100 | |
| 1101 | // Set the dynamic symbol indexes. INDEX is the index of the first |
| 1102 | // global dynamic symbol. Pointers to the symbols are stored into |
| 1103 | // the vector. The names are stored into the Stringpool. This |
| 1104 | // returns an updated dynamic symbol index. |
| 1105 | unsigned int |
| 1106 | set_dynsym_indexes(const Target*, unsigned int index, |
| 1107 | std::vector<Symbol*>*, Stringpool*, Versions*); |
| 1108 | |
| 1109 | // Finalize the symbol table after we have set the final addresses |
| 1110 | // of all the input sections. This sets the final symbol indexes, |
| 1111 | // values and adds the names to *POOL. INDEX is the index of the |
| 1112 | // first global symbol. OFF is the file offset of the global symbol |
| 1113 | // table, DYNOFF is the offset of the globals in the dynamic symbol |
| 1114 | // table, DYN_GLOBAL_INDEX is the index of the first global dynamic |
| 1115 | // symbol, and DYNCOUNT is the number of global dynamic symbols. |
| 1116 | // This records the parameters, and returns the new file offset. |
| 1117 | off_t |
| 1118 | finalize(unsigned int index, off_t off, off_t dynoff, |
| 1119 | size_t dyn_global_index, size_t dyncount, Stringpool* pool); |
| 1120 | |
| 1121 | // Write out the global symbols. |
| 1122 | void |
| 1123 | write_globals(const Input_objects*, const Stringpool*, const Stringpool*, |
| 1124 | Output_file*) const; |
| 1125 | |
| 1126 | // Write out a section symbol. Return the updated offset. |
| 1127 | void |
| 1128 | write_section_symbol(const Output_section*, Output_file*, off_t) const; |
| 1129 | |
| 1130 | private: |
| 1131 | Symbol_table(const Symbol_table&); |
| 1132 | Symbol_table& operator=(const Symbol_table&); |
| 1133 | |
| 1134 | // Make FROM a forwarder symbol to TO. |
| 1135 | void |
| 1136 | make_forwarder(Symbol* from, Symbol* to); |
| 1137 | |
| 1138 | // Add a symbol. |
| 1139 | template<int size, bool big_endian> |
| 1140 | Sized_symbol<size>* |
| 1141 | add_from_object(Object*, const char *name, Stringpool::Key name_key, |
| 1142 | const char *version, Stringpool::Key version_key, |
| 1143 | bool def, const elfcpp::Sym<size, big_endian>& sym, |
| 1144 | const elfcpp::Sym<size, big_endian>& orig_sym); |
| 1145 | |
| 1146 | // Resolve symbols. |
| 1147 | template<int size, bool big_endian> |
| 1148 | void |
| 1149 | resolve(Sized_symbol<size>* to, |
| 1150 | const elfcpp::Sym<size, big_endian>& sym, |
| 1151 | const elfcpp::Sym<size, big_endian>& orig_sym, |
| 1152 | Object*, const char* version); |
| 1153 | |
| 1154 | template<int size, bool big_endian> |
| 1155 | void |
| 1156 | resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from, |
| 1157 | const char* version ACCEPT_SIZE_ENDIAN); |
| 1158 | |
| 1159 | // Whether we should override a symbol, based on flags in |
| 1160 | // resolve.cc. |
| 1161 | static bool |
| 1162 | should_override(const Symbol*, unsigned int, Object*, bool*); |
| 1163 | |
| 1164 | // Override a symbol. |
| 1165 | template<int size, bool big_endian> |
| 1166 | void |
| 1167 | override(Sized_symbol<size>* tosym, |
| 1168 | const elfcpp::Sym<size, big_endian>& fromsym, |
| 1169 | Object* object, const char* version); |
| 1170 | |
| 1171 | // Whether we should override a symbol with a special symbol which |
| 1172 | // is automatically defined by the linker. |
| 1173 | static bool |
| 1174 | should_override_with_special(const Symbol*); |
| 1175 | |
| 1176 | // Override a symbol with a special symbol. |
| 1177 | template<int size> |
| 1178 | void |
| 1179 | override_with_special(Sized_symbol<size>* tosym, |
| 1180 | const Sized_symbol<size>* fromsym); |
| 1181 | |
| 1182 | // Record all weak alias sets for a dynamic object. |
| 1183 | template<int size> |
| 1184 | void |
| 1185 | record_weak_aliases(std::vector<Sized_symbol<size>*>*); |
| 1186 | |
| 1187 | // Define a special symbol. |
| 1188 | template<int size, bool big_endian> |
| 1189 | Sized_symbol<size>* |
| 1190 | define_special_symbol(const Target* target, const char** pname, |
| 1191 | const char** pversion, bool only_if_ref, |
| 1192 | Sized_symbol<size>** poldsym ACCEPT_SIZE_ENDIAN); |
| 1193 | |
| 1194 | // Define a symbol in an Output_data, sized version. |
| 1195 | template<int size> |
| 1196 | Sized_symbol<size>* |
| 1197 | do_define_in_output_data(const Target*, const char* name, |
| 1198 | const char* version, Output_data*, |
| 1199 | typename elfcpp::Elf_types<size>::Elf_Addr value, |
| 1200 | typename elfcpp::Elf_types<size>::Elf_WXword ssize, |
| 1201 | elfcpp::STT type, elfcpp::STB binding, |
| 1202 | elfcpp::STV visibility, unsigned char nonvis, |
| 1203 | bool offset_is_from_end, bool only_if_ref); |
| 1204 | |
| 1205 | // Define a symbol in an Output_segment, sized version. |
| 1206 | template<int size> |
| 1207 | Sized_symbol<size>* |
| 1208 | do_define_in_output_segment( |
| 1209 | const Target*, const char* name, const char* version, Output_segment* os, |
| 1210 | typename elfcpp::Elf_types<size>::Elf_Addr value, |
| 1211 | typename elfcpp::Elf_types<size>::Elf_WXword ssize, |
| 1212 | elfcpp::STT type, elfcpp::STB binding, |
| 1213 | elfcpp::STV visibility, unsigned char nonvis, |
| 1214 | Symbol::Segment_offset_base offset_base, bool only_if_ref); |
| 1215 | |
| 1216 | // Define a symbol as a constant, sized version. |
| 1217 | template<int size> |
| 1218 | Sized_symbol<size>* |
| 1219 | do_define_as_constant( |
| 1220 | const Target*, const char* name, const char* version, |
| 1221 | typename elfcpp::Elf_types<size>::Elf_Addr value, |
| 1222 | typename elfcpp::Elf_types<size>::Elf_WXword ssize, |
| 1223 | elfcpp::STT type, elfcpp::STB binding, |
| 1224 | elfcpp::STV visibility, unsigned char nonvis, |
| 1225 | bool only_if_ref); |
| 1226 | |
| 1227 | // Allocate the common symbols, sized version. |
| 1228 | template<int size> |
| 1229 | void |
| 1230 | do_allocate_commons(const General_options&, Layout*); |
| 1231 | |
| 1232 | // Implement detect_odr_violations. |
| 1233 | template<int size, bool big_endian> |
| 1234 | void |
| 1235 | sized_detect_odr_violations() const; |
| 1236 | |
| 1237 | // Finalize symbols specialized for size. |
| 1238 | template<int size> |
| 1239 | off_t |
| 1240 | sized_finalize(unsigned int, off_t, Stringpool*); |
| 1241 | |
| 1242 | // Write globals specialized for size and endianness. |
| 1243 | template<int size, bool big_endian> |
| 1244 | void |
| 1245 | sized_write_globals(const Input_objects*, const Stringpool*, |
| 1246 | const Stringpool*, Output_file*) const; |
| 1247 | |
| 1248 | // Write out a symbol to P. |
| 1249 | template<int size, bool big_endian> |
| 1250 | void |
| 1251 | sized_write_symbol(Sized_symbol<size>*, |
| 1252 | typename elfcpp::Elf_types<size>::Elf_Addr value, |
| 1253 | unsigned int shndx, |
| 1254 | const Stringpool*, unsigned char* p |
| 1255 | ACCEPT_SIZE_ENDIAN) const; |
| 1256 | |
| 1257 | // Possibly warn about an undefined symbol from a dynamic object. |
| 1258 | void |
| 1259 | warn_about_undefined_dynobj_symbol(const Input_objects*, Symbol*) const; |
| 1260 | |
| 1261 | // Write out a section symbol, specialized for size and endianness. |
| 1262 | template<int size, bool big_endian> |
| 1263 | void |
| 1264 | sized_write_section_symbol(const Output_section*, Output_file*, off_t) const; |
| 1265 | |
| 1266 | // The type of the symbol hash table. |
| 1267 | |
| 1268 | typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key; |
| 1269 | |
| 1270 | struct Symbol_table_hash |
| 1271 | { |
| 1272 | size_t |
| 1273 | operator()(const Symbol_table_key&) const; |
| 1274 | }; |
| 1275 | |
| 1276 | struct Symbol_table_eq |
| 1277 | { |
| 1278 | bool |
| 1279 | operator()(const Symbol_table_key&, const Symbol_table_key&) const; |
| 1280 | }; |
| 1281 | |
| 1282 | typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash, |
| 1283 | Symbol_table_eq> Symbol_table_type; |
| 1284 | |
| 1285 | // The type of the list of common symbols. |
| 1286 | typedef std::vector<Symbol*> Commons_type; |
| 1287 | |
| 1288 | // A map from symbols with COPY relocs to the dynamic objects where |
| 1289 | // they are defined. |
| 1290 | typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs; |
| 1291 | |
| 1292 | // A map from symbol name (as a pointer into the namepool) to all |
| 1293 | // the locations the symbols is (weakly) defined (and certain other |
| 1294 | // conditions are met). This map will be used later to detect |
| 1295 | // possible One Definition Rule (ODR) violations. |
| 1296 | struct Symbol_location |
| 1297 | { |
| 1298 | Object* object; // Object where the symbol is defined. |
| 1299 | unsigned int shndx; // Section-in-object where the symbol is defined. |
| 1300 | off_t offset; // Offset-in-section where the symbol is defined. |
| 1301 | bool operator==(const Symbol_location& that) const |
| 1302 | { |
| 1303 | return (this->object == that.object |
| 1304 | && this->shndx == that.shndx |
| 1305 | && this->offset == that.offset); |
| 1306 | } |
| 1307 | }; |
| 1308 | |
| 1309 | struct Symbol_location_hash |
| 1310 | { |
| 1311 | size_t operator()(const Symbol_location& loc) const |
| 1312 | { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; } |
| 1313 | }; |
| 1314 | |
| 1315 | typedef Unordered_map<const char*, |
| 1316 | Unordered_set<Symbol_location, Symbol_location_hash> > |
| 1317 | Odr_map; |
| 1318 | |
| 1319 | // We increment this every time we see a new undefined symbol, for |
| 1320 | // use in archive groups. |
| 1321 | int saw_undefined_; |
| 1322 | // The index of the first global symbol in the output file. |
| 1323 | unsigned int first_global_index_; |
| 1324 | // The file offset within the output symtab section where we should |
| 1325 | // write the table. |
| 1326 | off_t offset_; |
| 1327 | // The number of global symbols we want to write out. |
| 1328 | size_t output_count_; |
| 1329 | // The file offset of the global dynamic symbols, or 0 if none. |
| 1330 | off_t dynamic_offset_; |
| 1331 | // The index of the first global dynamic symbol. |
| 1332 | unsigned int first_dynamic_global_index_; |
| 1333 | // The number of global dynamic symbols, or 0 if none. |
| 1334 | off_t dynamic_count_; |
| 1335 | // The symbol hash table. |
| 1336 | Symbol_table_type table_; |
| 1337 | // A pool of symbol names. This is used for all global symbols. |
| 1338 | // Entries in the hash table point into this pool. |
| 1339 | Stringpool namepool_; |
| 1340 | // Forwarding symbols. |
| 1341 | Unordered_map<const Symbol*, Symbol*> forwarders_; |
| 1342 | // Weak aliases. A symbol in this list points to the next alias. |
| 1343 | // The aliases point to each other in a circular list. |
| 1344 | Unordered_map<Symbol*, Symbol*> weak_aliases_; |
| 1345 | // We don't expect there to be very many common symbols, so we keep |
| 1346 | // a list of them. When we find a common symbol we add it to this |
| 1347 | // list. It is possible that by the time we process the list the |
| 1348 | // symbol is no longer a common symbol. It may also have become a |
| 1349 | // forwarder. |
| 1350 | Commons_type commons_; |
| 1351 | // Manage symbol warnings. |
| 1352 | Warnings warnings_; |
| 1353 | // Manage potential One Definition Rule (ODR) violations. |
| 1354 | Odr_map candidate_odr_violations_; |
| 1355 | |
| 1356 | // When we emit a COPY reloc for a symbol, we define it in an |
| 1357 | // Output_data. When it's time to emit version information for it, |
| 1358 | // we need to know the dynamic object in which we found the original |
| 1359 | // definition. This maps symbols with COPY relocs to the dynamic |
| 1360 | // object where they were defined. |
| 1361 | Copied_symbol_dynobjs copied_symbol_dynobjs_; |
| 1362 | }; |
| 1363 | |
| 1364 | // We inline get_sized_symbol for efficiency. |
| 1365 | |
| 1366 | template<int size> |
| 1367 | Sized_symbol<size>* |
| 1368 | Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const |
| 1369 | { |
| 1370 | gold_assert(size == parameters->get_size()); |
| 1371 | return static_cast<Sized_symbol<size>*>(sym); |
| 1372 | } |
| 1373 | |
| 1374 | template<int size> |
| 1375 | const Sized_symbol<size>* |
| 1376 | Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const |
| 1377 | { |
| 1378 | gold_assert(size == parameters->get_size()); |
| 1379 | return static_cast<const Sized_symbol<size>*>(sym); |
| 1380 | } |
| 1381 | |
| 1382 | } // End namespace gold. |
| 1383 | |
| 1384 | #endif // !defined(GOLD_SYMTAB_H) |