| 1 | // dynobj.h -- dynamic object support for gold -*- 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 | #ifndef GOLD_DYNOBJ_H |
| 24 | #define GOLD_DYNOBJ_H |
| 25 | |
| 26 | #include <vector> |
| 27 | |
| 28 | #include "stringpool.h" |
| 29 | #include "object.h" |
| 30 | |
| 31 | namespace gold |
| 32 | { |
| 33 | |
| 34 | class Version_script_info; |
| 35 | |
| 36 | // A dynamic object (ET_DYN). This is an abstract base class itself. |
| 37 | // The implementations is the template class Sized_dynobj. |
| 38 | |
| 39 | class Dynobj : public Object |
| 40 | { |
| 41 | public: |
| 42 | // We keep a list of all the DT_NEEDED entries we find. |
| 43 | typedef std::vector<std::string> Needed; |
| 44 | |
| 45 | Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0); |
| 46 | |
| 47 | // Return the name to use in a DT_NEEDED entry for this object. |
| 48 | const char* |
| 49 | soname() const |
| 50 | { return this->soname_.c_str(); } |
| 51 | |
| 52 | // Return the list of DT_NEEDED strings. |
| 53 | const Needed& |
| 54 | needed() const |
| 55 | { return this->needed_; } |
| 56 | |
| 57 | // Return whether this dynamic object has any DT_NEEDED entries |
| 58 | // which were not seen during the link. |
| 59 | bool |
| 60 | has_unknown_needed_entries() const |
| 61 | { |
| 62 | gold_assert(this->unknown_needed_ != UNKNOWN_NEEDED_UNSET); |
| 63 | return this->unknown_needed_ == UNKNOWN_NEEDED_TRUE; |
| 64 | } |
| 65 | |
| 66 | // Set whether this dynamic object has any DT_NEEDED entries which |
| 67 | // were not seen during the link. |
| 68 | void |
| 69 | set_has_unknown_needed_entries(bool set) |
| 70 | { |
| 71 | gold_assert(this->unknown_needed_ == UNKNOWN_NEEDED_UNSET); |
| 72 | this->unknown_needed_ = set ? UNKNOWN_NEEDED_TRUE : UNKNOWN_NEEDED_FALSE; |
| 73 | } |
| 74 | |
| 75 | // Compute the ELF hash code for a string. |
| 76 | static uint32_t |
| 77 | elf_hash(const char*); |
| 78 | |
| 79 | // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN. |
| 80 | // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the |
| 81 | // number of local dynamic symbols, which is the index of the first |
| 82 | // dynamic gobal symbol. |
| 83 | static void |
| 84 | create_elf_hash_table(const std::vector<Symbol*>& dynsyms, |
| 85 | unsigned int local_dynsym_count, |
| 86 | unsigned char** pphash, |
| 87 | unsigned int* phashlen); |
| 88 | |
| 89 | // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS |
| 90 | // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number |
| 91 | // of local dynamic symbols, which is the index of the first dynamic |
| 92 | // gobal symbol. |
| 93 | static void |
| 94 | create_gnu_hash_table(const std::vector<Symbol*>& dynsyms, |
| 95 | unsigned int local_dynsym_count, |
| 96 | unsigned char** pphash, unsigned int* phashlen); |
| 97 | |
| 98 | protected: |
| 99 | // Set the DT_SONAME string. |
| 100 | void |
| 101 | set_soname_string(const char* s) |
| 102 | { this->soname_.assign(s); } |
| 103 | |
| 104 | // Add an entry to the list of DT_NEEDED strings. |
| 105 | void |
| 106 | add_needed(const char* s) |
| 107 | { this->needed_.push_back(std::string(s)); } |
| 108 | |
| 109 | private: |
| 110 | // Compute the GNU hash code for a string. |
| 111 | static uint32_t |
| 112 | gnu_hash(const char*); |
| 113 | |
| 114 | // Compute the number of hash buckets to use. |
| 115 | static unsigned int |
| 116 | compute_bucket_count(const std::vector<uint32_t>& hashcodes, |
| 117 | bool for_gnu_hash_table); |
| 118 | |
| 119 | // Sized version of create_elf_hash_table. |
| 120 | template<bool big_endian> |
| 121 | static void |
| 122 | sized_create_elf_hash_table(const std::vector<uint32_t>& bucket, |
| 123 | const std::vector<uint32_t>& chain, |
| 124 | unsigned char* phash, |
| 125 | unsigned int hashlen); |
| 126 | |
| 127 | // Sized version of create_gnu_hash_table. |
| 128 | template<int size, bool big_endian> |
| 129 | static void |
| 130 | sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms, |
| 131 | const std::vector<uint32_t>& dynsym_hashvals, |
| 132 | unsigned int unhashed_dynsym_count, |
| 133 | unsigned char** pphash, |
| 134 | unsigned int* phashlen); |
| 135 | |
| 136 | // Values for the has_unknown_needed_entries_ field. |
| 137 | enum Unknown_needed |
| 138 | { |
| 139 | UNKNOWN_NEEDED_UNSET, |
| 140 | UNKNOWN_NEEDED_TRUE, |
| 141 | UNKNOWN_NEEDED_FALSE |
| 142 | }; |
| 143 | |
| 144 | // The DT_SONAME name, if any. |
| 145 | std::string soname_; |
| 146 | // The list of DT_NEEDED entries. |
| 147 | Needed needed_; |
| 148 | // Whether this dynamic object has any DT_NEEDED entries not seen |
| 149 | // during the link. |
| 150 | Unknown_needed unknown_needed_; |
| 151 | }; |
| 152 | |
| 153 | // A dynamic object, size and endian specific version. |
| 154 | |
| 155 | template<int size, bool big_endian> |
| 156 | class Sized_dynobj : public Dynobj |
| 157 | { |
| 158 | public: |
| 159 | Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset, |
| 160 | const typename elfcpp::Ehdr<size, big_endian>&); |
| 161 | |
| 162 | // Set up the object file based on the ELF header. |
| 163 | void |
| 164 | setup(const typename elfcpp::Ehdr<size, big_endian>&); |
| 165 | |
| 166 | // Read the symbols. |
| 167 | void |
| 168 | do_read_symbols(Read_symbols_data*); |
| 169 | |
| 170 | // Lay out the input sections. |
| 171 | void |
| 172 | do_layout(Symbol_table*, Layout*, Read_symbols_data*); |
| 173 | |
| 174 | // Add the symbols to the symbol table. |
| 175 | void |
| 176 | do_add_symbols(Symbol_table*, Read_symbols_data*); |
| 177 | |
| 178 | // Get the size of a section. |
| 179 | uint64_t |
| 180 | do_section_size(unsigned int shndx) |
| 181 | { return this->elf_file_.section_size(shndx); } |
| 182 | |
| 183 | // Get the name of a section. |
| 184 | std::string |
| 185 | do_section_name(unsigned int shndx) |
| 186 | { return this->elf_file_.section_name(shndx); } |
| 187 | |
| 188 | // Return a view of the contents of a section. Set *PLEN to the |
| 189 | // size. |
| 190 | Object::Location |
| 191 | do_section_contents(unsigned int shndx) |
| 192 | { return this->elf_file_.section_contents(shndx); } |
| 193 | |
| 194 | // Return section flags. |
| 195 | uint64_t |
| 196 | do_section_flags(unsigned int shndx) |
| 197 | { return this->elf_file_.section_flags(shndx); } |
| 198 | |
| 199 | // Return section address. |
| 200 | uint64_t |
| 201 | do_section_address(unsigned int shndx) |
| 202 | { return this->elf_file_.section_addr(shndx); } |
| 203 | |
| 204 | // Return section type. |
| 205 | unsigned int |
| 206 | do_section_type(unsigned int shndx) |
| 207 | { return this->elf_file_.section_type(shndx); } |
| 208 | |
| 209 | // Return the section link field. |
| 210 | unsigned int |
| 211 | do_section_link(unsigned int shndx) |
| 212 | { return this->elf_file_.section_link(shndx); } |
| 213 | |
| 214 | // Return the section link field. |
| 215 | unsigned int |
| 216 | do_section_info(unsigned int shndx) |
| 217 | { return this->elf_file_.section_info(shndx); } |
| 218 | |
| 219 | // Return the section alignment. |
| 220 | uint64_t |
| 221 | do_section_addralign(unsigned int shndx) |
| 222 | { return this->elf_file_.section_addralign(shndx); } |
| 223 | |
| 224 | private: |
| 225 | // For convenience. |
| 226 | typedef Sized_dynobj<size, big_endian> This; |
| 227 | static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; |
| 228 | static const int sym_size = elfcpp::Elf_sizes<size>::sym_size; |
| 229 | static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size; |
| 230 | typedef elfcpp::Shdr<size, big_endian> Shdr; |
| 231 | typedef elfcpp::Dyn<size, big_endian> Dyn; |
| 232 | |
| 233 | // Find the dynamic symbol table and the version sections, given the |
| 234 | // section headers. |
| 235 | void |
| 236 | find_dynsym_sections(const unsigned char* pshdrs, |
| 237 | unsigned int* pdynshm_shndx, |
| 238 | unsigned int* pversym_shndx, |
| 239 | unsigned int* pverdef_shndx, |
| 240 | unsigned int* pverneed_shndx, |
| 241 | unsigned int* pdynamic_shndx); |
| 242 | |
| 243 | // Read the dynamic symbol section SHNDX. |
| 244 | void |
| 245 | read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx, |
| 246 | elfcpp::SHT type, unsigned int link, |
| 247 | File_view** view, section_size_type* view_size, |
| 248 | unsigned int* view_info); |
| 249 | |
| 250 | // Read the dynamic tags. |
| 251 | void |
| 252 | read_dynamic(const unsigned char* pshdrs, unsigned int dynamic_shndx, |
| 253 | unsigned int strtab_shndx, const unsigned char* strtabu, |
| 254 | off_t strtab_size); |
| 255 | |
| 256 | // Mapping from version number to version name. |
| 257 | typedef std::vector<const char*> Version_map; |
| 258 | |
| 259 | // Create the version map. |
| 260 | void |
| 261 | make_version_map(Read_symbols_data* sd, Version_map*) const; |
| 262 | |
| 263 | // Add version definitions to the version map. |
| 264 | void |
| 265 | make_verdef_map(Read_symbols_data* sd, Version_map*) const; |
| 266 | |
| 267 | // Add version references to the version map. |
| 268 | void |
| 269 | make_verneed_map(Read_symbols_data* sd, Version_map*) const; |
| 270 | |
| 271 | // Add an entry to the version map. |
| 272 | void |
| 273 | set_version_map(Version_map*, unsigned int ndx, const char* name) const; |
| 274 | |
| 275 | // General access to the ELF file. |
| 276 | elfcpp::Elf_file<size, big_endian, Object> elf_file_; |
| 277 | }; |
| 278 | |
| 279 | // A base class for Verdef and Verneed_version which just handles the |
| 280 | // version index which will be stored in the SHT_GNU_versym section. |
| 281 | |
| 282 | class Version_base |
| 283 | { |
| 284 | public: |
| 285 | Version_base() |
| 286 | : index_(-1U) |
| 287 | { } |
| 288 | |
| 289 | virtual |
| 290 | ~Version_base() |
| 291 | { } |
| 292 | |
| 293 | // Return the version index. |
| 294 | unsigned int |
| 295 | index() const |
| 296 | { |
| 297 | gold_assert(this->index_ != -1U); |
| 298 | return this->index_; |
| 299 | } |
| 300 | |
| 301 | // Set the version index. |
| 302 | void |
| 303 | set_index(unsigned int index) |
| 304 | { |
| 305 | gold_assert(this->index_ == -1U); |
| 306 | this->index_ = index; |
| 307 | } |
| 308 | |
| 309 | // Clear the weak flag in a version definition. |
| 310 | virtual void |
| 311 | clear_weak() = 0; |
| 312 | |
| 313 | private: |
| 314 | Version_base(const Version_base&); |
| 315 | Version_base& operator=(const Version_base&); |
| 316 | |
| 317 | // The index of the version definition or reference. |
| 318 | unsigned int index_; |
| 319 | }; |
| 320 | |
| 321 | // This class handles a version being defined in the file we are |
| 322 | // generating. |
| 323 | |
| 324 | class Verdef : public Version_base |
| 325 | { |
| 326 | public: |
| 327 | Verdef(const char* name, const std::vector<std::string>& deps, |
| 328 | bool is_base, bool is_weak, bool is_symbol_created) |
| 329 | : name_(name), deps_(deps), is_base_(is_base), is_weak_(is_weak), |
| 330 | is_symbol_created_(is_symbol_created) |
| 331 | { } |
| 332 | |
| 333 | // Return the version name. |
| 334 | const char* |
| 335 | name() const |
| 336 | { return this->name_; } |
| 337 | |
| 338 | // Return the number of dependencies. |
| 339 | unsigned int |
| 340 | count_dependencies() const |
| 341 | { return this->deps_.size(); } |
| 342 | |
| 343 | // Add a dependency to this version. The NAME should be |
| 344 | // canonicalized in the dynamic Stringpool. |
| 345 | void |
| 346 | add_dependency(const char* name) |
| 347 | { this->deps_.push_back(name); } |
| 348 | |
| 349 | // Return whether this definition is weak. |
| 350 | bool |
| 351 | is_weak() const |
| 352 | { return this->is_weak_; } |
| 353 | |
| 354 | // Clear the weak flag. |
| 355 | void |
| 356 | clear_weak() |
| 357 | { this->is_weak_ = false; } |
| 358 | |
| 359 | // Return whether a version symbol has been created for this |
| 360 | // definition. |
| 361 | bool |
| 362 | is_symbol_created() const |
| 363 | { return this->is_symbol_created_; } |
| 364 | |
| 365 | // Write contents to buffer. |
| 366 | template<int size, bool big_endian> |
| 367 | unsigned char* |
| 368 | write(const Stringpool*, bool is_last, unsigned char*) const; |
| 369 | |
| 370 | private: |
| 371 | Verdef(const Verdef&); |
| 372 | Verdef& operator=(const Verdef&); |
| 373 | |
| 374 | // The type of the list of version dependencies. Each dependency |
| 375 | // should be canonicalized in the dynamic Stringpool. |
| 376 | typedef std::vector<std::string> Deps; |
| 377 | |
| 378 | // The name of this version. This should be canonicalized in the |
| 379 | // dynamic Stringpool. |
| 380 | const char* name_; |
| 381 | // A list of other versions which this version depends upon. |
| 382 | Deps deps_; |
| 383 | // Whether this is the base version. |
| 384 | bool is_base_; |
| 385 | // Whether this version is weak. |
| 386 | bool is_weak_; |
| 387 | // Whether a version symbol has been created. |
| 388 | bool is_symbol_created_; |
| 389 | }; |
| 390 | |
| 391 | // A referened version. This will be associated with a filename by |
| 392 | // Verneed. |
| 393 | |
| 394 | class Verneed_version : public Version_base |
| 395 | { |
| 396 | public: |
| 397 | Verneed_version(const char* version) |
| 398 | : version_(version) |
| 399 | { } |
| 400 | |
| 401 | // Return the version name. |
| 402 | const char* |
| 403 | version() const |
| 404 | { return this->version_; } |
| 405 | |
| 406 | // Clear the weak flag. This is invalid for a reference. |
| 407 | void |
| 408 | clear_weak() |
| 409 | { gold_unreachable(); } |
| 410 | |
| 411 | private: |
| 412 | Verneed_version(const Verneed_version&); |
| 413 | Verneed_version& operator=(const Verneed_version&); |
| 414 | |
| 415 | const char* version_; |
| 416 | }; |
| 417 | |
| 418 | // Version references in a single dynamic object. |
| 419 | |
| 420 | class Verneed |
| 421 | { |
| 422 | public: |
| 423 | Verneed(const char* filename) |
| 424 | : filename_(filename), need_versions_() |
| 425 | { } |
| 426 | |
| 427 | ~Verneed(); |
| 428 | |
| 429 | // Return the file name. |
| 430 | const char* |
| 431 | filename() const |
| 432 | { return this->filename_; } |
| 433 | |
| 434 | // Return the number of versions. |
| 435 | unsigned int |
| 436 | count_versions() const |
| 437 | { return this->need_versions_.size(); } |
| 438 | |
| 439 | // Add a version name. The name should be canonicalized in the |
| 440 | // dynamic Stringpool. If the name is already present, this does |
| 441 | // nothing. |
| 442 | Verneed_version* |
| 443 | add_name(const char* name); |
| 444 | |
| 445 | // Set the version indexes, starting at INDEX. Return the updated |
| 446 | // INDEX. |
| 447 | unsigned int |
| 448 | finalize(unsigned int index); |
| 449 | |
| 450 | // Write contents to buffer. |
| 451 | template<int size, bool big_endian> |
| 452 | unsigned char* |
| 453 | write(const Stringpool*, bool is_last, unsigned char*) const; |
| 454 | |
| 455 | private: |
| 456 | Verneed(const Verneed&); |
| 457 | Verneed& operator=(const Verneed&); |
| 458 | |
| 459 | // The type of the list of version names. Each name should be |
| 460 | // canonicalized in the dynamic Stringpool. |
| 461 | typedef std::vector<Verneed_version*> Need_versions; |
| 462 | |
| 463 | // The filename of the dynamic object. This should be |
| 464 | // canonicalized in the dynamic Stringpool. |
| 465 | const char* filename_; |
| 466 | // The list of version names. |
| 467 | Need_versions need_versions_; |
| 468 | }; |
| 469 | |
| 470 | // This class handles version definitions and references which go into |
| 471 | // the output file. |
| 472 | |
| 473 | class Versions |
| 474 | { |
| 475 | public: |
| 476 | Versions(const Version_script_info&, Stringpool*); |
| 477 | |
| 478 | ~Versions(); |
| 479 | |
| 480 | // SYM is going into the dynamic symbol table and has a version. |
| 481 | // Record the appropriate version information. |
| 482 | void |
| 483 | record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym); |
| 484 | |
| 485 | // Set the version indexes. DYNSYM_INDEX is the index we should use |
| 486 | // for the next dynamic symbol. We add new dynamic symbols to SYMS |
| 487 | // and return an updated DYNSYM_INDEX. |
| 488 | unsigned int |
| 489 | finalize(Symbol_table* symtab, unsigned int dynsym_index, |
| 490 | std::vector<Symbol*>* syms); |
| 491 | |
| 492 | // Return whether there are any version definitions. |
| 493 | bool |
| 494 | any_defs() const |
| 495 | { return !this->defs_.empty(); } |
| 496 | |
| 497 | // Return whether there are any version references. |
| 498 | bool |
| 499 | any_needs() const |
| 500 | { return !this->needs_.empty(); } |
| 501 | |
| 502 | // Build an allocated buffer holding the contents of the symbol |
| 503 | // version section (.gnu.version). |
| 504 | template<int size, bool big_endian> |
| 505 | void |
| 506 | symbol_section_contents(const Symbol_table*, const Stringpool*, |
| 507 | unsigned int local_symcount, |
| 508 | const std::vector<Symbol*>& syms, |
| 509 | unsigned char**, unsigned int*) const; |
| 510 | |
| 511 | // Build an allocated buffer holding the contents of the version |
| 512 | // definition section (.gnu.version_d). |
| 513 | template<int size, bool big_endian> |
| 514 | void |
| 515 | def_section_contents(const Stringpool*, unsigned char**, |
| 516 | unsigned int* psize, unsigned int* pentries) const; |
| 517 | |
| 518 | // Build an allocated buffer holding the contents of the version |
| 519 | // reference section (.gnu.version_r). |
| 520 | template<int size, bool big_endian> |
| 521 | void |
| 522 | need_section_contents(const Stringpool*, unsigned char**, |
| 523 | unsigned int* psize, unsigned int* pentries) const; |
| 524 | |
| 525 | const Version_script_info& |
| 526 | version_script() const |
| 527 | { return this->version_script_; } |
| 528 | |
| 529 | private: |
| 530 | Versions(const Versions&); |
| 531 | Versions& operator=(const Versions&); |
| 532 | |
| 533 | // The type of the list of version definitions. |
| 534 | typedef std::vector<Verdef*> Defs; |
| 535 | |
| 536 | // The type of the list of version references. |
| 537 | typedef std::vector<Verneed*> Needs; |
| 538 | |
| 539 | // Handle a symbol SYM defined with version VERSION. |
| 540 | void |
| 541 | add_def(const Symbol* sym, const char* version, Stringpool::Key); |
| 542 | |
| 543 | // Add a reference to version NAME in file FILENAME. |
| 544 | void |
| 545 | add_need(Stringpool*, const char* filename, const char* name, |
| 546 | Stringpool::Key); |
| 547 | |
| 548 | // Get the dynamic object to use for SYM. |
| 549 | Dynobj* |
| 550 | get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const; |
| 551 | |
| 552 | // Return the version index to use for SYM. |
| 553 | unsigned int |
| 554 | version_index(const Symbol_table*, const Stringpool*, |
| 555 | const Symbol* sym) const; |
| 556 | |
| 557 | // We keep a hash table mapping canonicalized name/version pairs to |
| 558 | // a version base. |
| 559 | typedef std::pair<Stringpool::Key, Stringpool::Key> Key; |
| 560 | |
| 561 | struct Version_table_hash |
| 562 | { |
| 563 | size_t |
| 564 | operator()(const Key& k) const |
| 565 | { return k.first + k.second; } |
| 566 | }; |
| 567 | |
| 568 | struct Version_table_eq |
| 569 | { |
| 570 | bool |
| 571 | operator()(const Key& k1, const Key& k2) const |
| 572 | { return k1.first == k2.first && k1.second == k2.second; } |
| 573 | }; |
| 574 | |
| 575 | typedef Unordered_map<Key, Version_base*, Version_table_hash, |
| 576 | Version_table_eq> Version_table; |
| 577 | |
| 578 | // The version definitions. |
| 579 | Defs defs_; |
| 580 | // The version references. |
| 581 | Needs needs_; |
| 582 | // The mapping from a canonicalized version/filename pair to a |
| 583 | // version index. The filename may be NULL. |
| 584 | Version_table version_table_; |
| 585 | // Whether the version indexes have been set. |
| 586 | bool is_finalized_; |
| 587 | // Contents of --version-script, if passed, or NULL. |
| 588 | const Version_script_info& version_script_; |
| 589 | }; |
| 590 | |
| 591 | } // End namespace gold. |
| 592 | |
| 593 | #endif // !defined(GOLD_DYNOBJ_H) |