| 1 | // i386.cc -- i386 target support for gold. |
| 2 | |
| 3 | // Copyright 2006, 2007, 2008, 2009, 2010 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 <cstring> |
| 26 | |
| 27 | #include "elfcpp.h" |
| 28 | #include "parameters.h" |
| 29 | #include "reloc.h" |
| 30 | #include "i386.h" |
| 31 | #include "object.h" |
| 32 | #include "symtab.h" |
| 33 | #include "layout.h" |
| 34 | #include "output.h" |
| 35 | #include "copy-relocs.h" |
| 36 | #include "target.h" |
| 37 | #include "target-reloc.h" |
| 38 | #include "target-select.h" |
| 39 | #include "tls.h" |
| 40 | #include "freebsd.h" |
| 41 | #include "gc.h" |
| 42 | |
| 43 | namespace |
| 44 | { |
| 45 | |
| 46 | using namespace gold; |
| 47 | |
| 48 | // A class to handle the PLT data. |
| 49 | |
| 50 | class Output_data_plt_i386 : public Output_section_data |
| 51 | { |
| 52 | public: |
| 53 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 54 | |
| 55 | Output_data_plt_i386(Symbol_table*, Layout*, Output_data_space*); |
| 56 | |
| 57 | // Add an entry to the PLT. |
| 58 | void |
| 59 | add_entry(Symbol* gsym); |
| 60 | |
| 61 | // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. |
| 62 | unsigned int |
| 63 | add_local_ifunc_entry(Sized_relobj<32, false>* relobj, |
| 64 | unsigned int local_sym_index); |
| 65 | |
| 66 | // Return the .rel.plt section data. |
| 67 | Reloc_section* |
| 68 | rel_plt() const |
| 69 | { return this->rel_; } |
| 70 | |
| 71 | // Return where the TLS_DESC relocations should go. |
| 72 | Reloc_section* |
| 73 | rel_tls_desc(Layout*); |
| 74 | |
| 75 | // Return the number of PLT entries. |
| 76 | unsigned int |
| 77 | entry_count() const |
| 78 | { return this->count_; } |
| 79 | |
| 80 | // Return the offset of the first non-reserved PLT entry. |
| 81 | static unsigned int |
| 82 | first_plt_entry_offset() |
| 83 | { return plt_entry_size; } |
| 84 | |
| 85 | // Return the size of a PLT entry. |
| 86 | static unsigned int |
| 87 | get_plt_entry_size() |
| 88 | { return plt_entry_size; } |
| 89 | |
| 90 | protected: |
| 91 | void |
| 92 | do_adjust_output_section(Output_section* os); |
| 93 | |
| 94 | // Write to a map file. |
| 95 | void |
| 96 | do_print_to_mapfile(Mapfile* mapfile) const |
| 97 | { mapfile->print_output_data(this, _("** PLT")); } |
| 98 | |
| 99 | private: |
| 100 | // The size of an entry in the PLT. |
| 101 | static const int plt_entry_size = 16; |
| 102 | |
| 103 | // The first entry in the PLT for an executable. |
| 104 | static unsigned char exec_first_plt_entry[plt_entry_size]; |
| 105 | |
| 106 | // The first entry in the PLT for a shared object. |
| 107 | static unsigned char dyn_first_plt_entry[plt_entry_size]; |
| 108 | |
| 109 | // Other entries in the PLT for an executable. |
| 110 | static unsigned char exec_plt_entry[plt_entry_size]; |
| 111 | |
| 112 | // Other entries in the PLT for a shared object. |
| 113 | static unsigned char dyn_plt_entry[plt_entry_size]; |
| 114 | |
| 115 | // Set the final size. |
| 116 | void |
| 117 | set_final_data_size() |
| 118 | { this->set_data_size((this->count_ + 1) * plt_entry_size); } |
| 119 | |
| 120 | // Write out the PLT data. |
| 121 | void |
| 122 | do_write(Output_file*); |
| 123 | |
| 124 | // We keep a list of global STT_GNU_IFUNC symbols, each with its |
| 125 | // offset in the GOT. |
| 126 | struct Global_ifunc |
| 127 | { |
| 128 | Symbol* sym; |
| 129 | unsigned int got_offset; |
| 130 | }; |
| 131 | |
| 132 | // We keep a list of local STT_GNU_IFUNC symbols, each with its |
| 133 | // offset in the GOT. |
| 134 | struct Local_ifunc |
| 135 | { |
| 136 | Sized_relobj<32, false>* object; |
| 137 | unsigned int local_sym_index; |
| 138 | unsigned int got_offset; |
| 139 | }; |
| 140 | |
| 141 | // The reloc section. |
| 142 | Reloc_section* rel_; |
| 143 | // The TLS_DESC relocations, if necessary. These must follow the |
| 144 | // regular PLT relocs. |
| 145 | Reloc_section* tls_desc_rel_; |
| 146 | // The .got.plt section. |
| 147 | Output_data_space* got_plt_; |
| 148 | // The number of PLT entries. |
| 149 | unsigned int count_; |
| 150 | // Global STT_GNU_IFUNC symbols. |
| 151 | std::vector<Global_ifunc> global_ifuncs_; |
| 152 | // Local STT_GNU_IFUNC symbols. |
| 153 | std::vector<Local_ifunc> local_ifuncs_; |
| 154 | }; |
| 155 | |
| 156 | // The i386 target class. |
| 157 | // TLS info comes from |
| 158 | // http://people.redhat.com/drepper/tls.pdf |
| 159 | // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt |
| 160 | |
| 161 | class Target_i386 : public Target_freebsd<32, false> |
| 162 | { |
| 163 | public: |
| 164 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 165 | |
| 166 | Target_i386() |
| 167 | : Target_freebsd<32, false>(&i386_info), |
| 168 | got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL), |
| 169 | global_offset_table_(NULL), rel_dyn_(NULL), |
| 170 | copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL), |
| 171 | got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) |
| 172 | { } |
| 173 | |
| 174 | inline bool |
| 175 | can_check_for_function_pointers() const |
| 176 | { return true; } |
| 177 | |
| 178 | // Process the relocations to determine unreferenced sections for |
| 179 | // garbage collection. |
| 180 | void |
| 181 | gc_process_relocs(Symbol_table* symtab, |
| 182 | Layout* layout, |
| 183 | Sized_relobj<32, false>* object, |
| 184 | unsigned int data_shndx, |
| 185 | unsigned int sh_type, |
| 186 | const unsigned char* prelocs, |
| 187 | size_t reloc_count, |
| 188 | Output_section* output_section, |
| 189 | bool needs_special_offset_handling, |
| 190 | size_t local_symbol_count, |
| 191 | const unsigned char* plocal_symbols); |
| 192 | |
| 193 | // Scan the relocations to look for symbol adjustments. |
| 194 | void |
| 195 | scan_relocs(Symbol_table* symtab, |
| 196 | Layout* layout, |
| 197 | Sized_relobj<32, false>* object, |
| 198 | unsigned int data_shndx, |
| 199 | unsigned int sh_type, |
| 200 | const unsigned char* prelocs, |
| 201 | size_t reloc_count, |
| 202 | Output_section* output_section, |
| 203 | bool needs_special_offset_handling, |
| 204 | size_t local_symbol_count, |
| 205 | const unsigned char* plocal_symbols); |
| 206 | |
| 207 | // Finalize the sections. |
| 208 | void |
| 209 | do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); |
| 210 | |
| 211 | // Return the value to use for a dynamic which requires special |
| 212 | // treatment. |
| 213 | uint64_t |
| 214 | do_dynsym_value(const Symbol*) const; |
| 215 | |
| 216 | // Relocate a section. |
| 217 | void |
| 218 | relocate_section(const Relocate_info<32, false>*, |
| 219 | unsigned int sh_type, |
| 220 | const unsigned char* prelocs, |
| 221 | size_t reloc_count, |
| 222 | Output_section* output_section, |
| 223 | bool needs_special_offset_handling, |
| 224 | unsigned char* view, |
| 225 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 226 | section_size_type view_size, |
| 227 | const Reloc_symbol_changes*); |
| 228 | |
| 229 | // Scan the relocs during a relocatable link. |
| 230 | void |
| 231 | scan_relocatable_relocs(Symbol_table* symtab, |
| 232 | Layout* layout, |
| 233 | Sized_relobj<32, false>* object, |
| 234 | unsigned int data_shndx, |
| 235 | unsigned int sh_type, |
| 236 | const unsigned char* prelocs, |
| 237 | size_t reloc_count, |
| 238 | Output_section* output_section, |
| 239 | bool needs_special_offset_handling, |
| 240 | size_t local_symbol_count, |
| 241 | const unsigned char* plocal_symbols, |
| 242 | Relocatable_relocs*); |
| 243 | |
| 244 | // Relocate a section during a relocatable link. |
| 245 | void |
| 246 | relocate_for_relocatable(const Relocate_info<32, false>*, |
| 247 | unsigned int sh_type, |
| 248 | const unsigned char* prelocs, |
| 249 | size_t reloc_count, |
| 250 | Output_section* output_section, |
| 251 | off_t offset_in_output_section, |
| 252 | const Relocatable_relocs*, |
| 253 | unsigned char* view, |
| 254 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 255 | section_size_type view_size, |
| 256 | unsigned char* reloc_view, |
| 257 | section_size_type reloc_view_size); |
| 258 | |
| 259 | // Return a string used to fill a code section with nops. |
| 260 | std::string |
| 261 | do_code_fill(section_size_type length) const; |
| 262 | |
| 263 | // Return whether SYM is defined by the ABI. |
| 264 | bool |
| 265 | do_is_defined_by_abi(const Symbol* sym) const |
| 266 | { return strcmp(sym->name(), "___tls_get_addr") == 0; } |
| 267 | |
| 268 | // Return whether a symbol name implies a local label. The UnixWare |
| 269 | // 2.1 cc generates temporary symbols that start with .X, so we |
| 270 | // recognize them here. FIXME: do other SVR4 compilers also use .X?. |
| 271 | // If so, we should move the .X recognition into |
| 272 | // Target::do_is_local_label_name. |
| 273 | bool |
| 274 | do_is_local_label_name(const char* name) const |
| 275 | { |
| 276 | if (name[0] == '.' && name[1] == 'X') |
| 277 | return true; |
| 278 | return Target::do_is_local_label_name(name); |
| 279 | } |
| 280 | |
| 281 | // Return the PLT section. |
| 282 | Output_data* |
| 283 | do_plt_section_for_global(const Symbol*) const |
| 284 | { return this->plt_section(); } |
| 285 | |
| 286 | Output_data* |
| 287 | do_plt_section_for_local(const Relobj*, unsigned int) const |
| 288 | { return this->plt_section(); } |
| 289 | |
| 290 | // Return whether SYM is call to a non-split function. |
| 291 | bool |
| 292 | do_is_call_to_non_split(const Symbol* sym, unsigned int) const; |
| 293 | |
| 294 | // Adjust -fstack-split code which calls non-stack-split code. |
| 295 | void |
| 296 | do_calls_non_split(Relobj* object, unsigned int shndx, |
| 297 | section_offset_type fnoffset, section_size_type fnsize, |
| 298 | unsigned char* view, section_size_type view_size, |
| 299 | std::string* from, std::string* to) const; |
| 300 | |
| 301 | // Return the size of the GOT section. |
| 302 | section_size_type |
| 303 | got_size() const |
| 304 | { |
| 305 | gold_assert(this->got_ != NULL); |
| 306 | return this->got_->data_size(); |
| 307 | } |
| 308 | |
| 309 | // Return the number of entries in the GOT. |
| 310 | unsigned int |
| 311 | got_entry_count() const |
| 312 | { |
| 313 | if (this->got_ == NULL) |
| 314 | return 0; |
| 315 | return this->got_size() / 4; |
| 316 | } |
| 317 | |
| 318 | // Return the number of entries in the PLT. |
| 319 | unsigned int |
| 320 | plt_entry_count() const; |
| 321 | |
| 322 | // Return the offset of the first non-reserved PLT entry. |
| 323 | unsigned int |
| 324 | first_plt_entry_offset() const; |
| 325 | |
| 326 | // Return the size of each PLT entry. |
| 327 | unsigned int |
| 328 | plt_entry_size() const; |
| 329 | |
| 330 | private: |
| 331 | // The class which scans relocations. |
| 332 | struct Scan |
| 333 | { |
| 334 | inline void |
| 335 | local(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| 336 | Sized_relobj<32, false>* object, |
| 337 | unsigned int data_shndx, |
| 338 | Output_section* output_section, |
| 339 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 340 | const elfcpp::Sym<32, false>& lsym); |
| 341 | |
| 342 | inline void |
| 343 | global(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| 344 | Sized_relobj<32, false>* object, |
| 345 | unsigned int data_shndx, |
| 346 | Output_section* output_section, |
| 347 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 348 | Symbol* gsym); |
| 349 | |
| 350 | inline bool |
| 351 | local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| 352 | Target_i386* target, |
| 353 | Sized_relobj<32, false>* object, |
| 354 | unsigned int data_shndx, |
| 355 | Output_section* output_section, |
| 356 | const elfcpp::Rel<32, false>& reloc, |
| 357 | unsigned int r_type, |
| 358 | const elfcpp::Sym<32, false>& lsym); |
| 359 | |
| 360 | inline bool |
| 361 | global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| 362 | Target_i386* target, |
| 363 | Sized_relobj<32, false>* object, |
| 364 | unsigned int data_shndx, |
| 365 | Output_section* output_section, |
| 366 | const elfcpp::Rel<32, false>& reloc, |
| 367 | unsigned int r_type, |
| 368 | Symbol* gsym); |
| 369 | |
| 370 | inline bool |
| 371 | possible_function_pointer_reloc(unsigned int r_type); |
| 372 | |
| 373 | bool |
| 374 | reloc_needs_plt_for_ifunc(Sized_relobj<32, false>*, unsigned int r_type); |
| 375 | |
| 376 | static void |
| 377 | unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type); |
| 378 | |
| 379 | static void |
| 380 | unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type, |
| 381 | Symbol*); |
| 382 | }; |
| 383 | |
| 384 | // The class which implements relocation. |
| 385 | class Relocate |
| 386 | { |
| 387 | public: |
| 388 | Relocate() |
| 389 | : skip_call_tls_get_addr_(false), |
| 390 | local_dynamic_type_(LOCAL_DYNAMIC_NONE) |
| 391 | { } |
| 392 | |
| 393 | ~Relocate() |
| 394 | { |
| 395 | if (this->skip_call_tls_get_addr_) |
| 396 | { |
| 397 | // FIXME: This needs to specify the location somehow. |
| 398 | gold_error(_("missing expected TLS relocation")); |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | // Return whether the static relocation needs to be applied. |
| 403 | inline bool |
| 404 | should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| 405 | int ref_flags, |
| 406 | bool is_32bit, |
| 407 | Output_section* output_section); |
| 408 | |
| 409 | // Do a relocation. Return false if the caller should not issue |
| 410 | // any warnings about this relocation. |
| 411 | inline bool |
| 412 | relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*, |
| 413 | size_t relnum, const elfcpp::Rel<32, false>&, |
| 414 | unsigned int r_type, const Sized_symbol<32>*, |
| 415 | const Symbol_value<32>*, |
| 416 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| 417 | section_size_type); |
| 418 | |
| 419 | private: |
| 420 | // Do a TLS relocation. |
| 421 | inline void |
| 422 | relocate_tls(const Relocate_info<32, false>*, Target_i386* target, |
| 423 | size_t relnum, const elfcpp::Rel<32, false>&, |
| 424 | unsigned int r_type, const Sized_symbol<32>*, |
| 425 | const Symbol_value<32>*, |
| 426 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| 427 | section_size_type); |
| 428 | |
| 429 | // Do a TLS General-Dynamic to Initial-Exec transition. |
| 430 | inline void |
| 431 | tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| 432 | Output_segment* tls_segment, |
| 433 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 434 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 435 | unsigned char* view, |
| 436 | section_size_type view_size); |
| 437 | |
| 438 | // Do a TLS General-Dynamic to Local-Exec transition. |
| 439 | inline void |
| 440 | tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 441 | Output_segment* tls_segment, |
| 442 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 443 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 444 | unsigned char* view, |
| 445 | section_size_type view_size); |
| 446 | |
| 447 | // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec |
| 448 | // transition. |
| 449 | inline void |
| 450 | tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| 451 | Output_segment* tls_segment, |
| 452 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 453 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 454 | unsigned char* view, |
| 455 | section_size_type view_size); |
| 456 | |
| 457 | // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec |
| 458 | // transition. |
| 459 | inline void |
| 460 | tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 461 | Output_segment* tls_segment, |
| 462 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 463 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 464 | unsigned char* view, |
| 465 | section_size_type view_size); |
| 466 | |
| 467 | // Do a TLS Local-Dynamic to Local-Exec transition. |
| 468 | inline void |
| 469 | tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 470 | Output_segment* tls_segment, |
| 471 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 472 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 473 | unsigned char* view, |
| 474 | section_size_type view_size); |
| 475 | |
| 476 | // Do a TLS Initial-Exec to Local-Exec transition. |
| 477 | static inline void |
| 478 | tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 479 | Output_segment* tls_segment, |
| 480 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 481 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 482 | unsigned char* view, |
| 483 | section_size_type view_size); |
| 484 | |
| 485 | // We need to keep track of which type of local dynamic relocation |
| 486 | // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly. |
| 487 | enum Local_dynamic_type |
| 488 | { |
| 489 | LOCAL_DYNAMIC_NONE, |
| 490 | LOCAL_DYNAMIC_SUN, |
| 491 | LOCAL_DYNAMIC_GNU |
| 492 | }; |
| 493 | |
| 494 | // This is set if we should skip the next reloc, which should be a |
| 495 | // PLT32 reloc against ___tls_get_addr. |
| 496 | bool skip_call_tls_get_addr_; |
| 497 | // The type of local dynamic relocation we have seen in the section |
| 498 | // being relocated, if any. |
| 499 | Local_dynamic_type local_dynamic_type_; |
| 500 | }; |
| 501 | |
| 502 | // A class which returns the size required for a relocation type, |
| 503 | // used while scanning relocs during a relocatable link. |
| 504 | class Relocatable_size_for_reloc |
| 505 | { |
| 506 | public: |
| 507 | unsigned int |
| 508 | get_size_for_reloc(unsigned int, Relobj*); |
| 509 | }; |
| 510 | |
| 511 | // Adjust TLS relocation type based on the options and whether this |
| 512 | // is a local symbol. |
| 513 | static tls::Tls_optimization |
| 514 | optimize_tls_reloc(bool is_final, int r_type); |
| 515 | |
| 516 | // Get the GOT section, creating it if necessary. |
| 517 | Output_data_got<32, false>* |
| 518 | got_section(Symbol_table*, Layout*); |
| 519 | |
| 520 | // Get the GOT PLT section. |
| 521 | Output_data_space* |
| 522 | got_plt_section() const |
| 523 | { |
| 524 | gold_assert(this->got_plt_ != NULL); |
| 525 | return this->got_plt_; |
| 526 | } |
| 527 | |
| 528 | // Get the GOT section for TLSDESC entries. |
| 529 | Output_data_got<32, false>* |
| 530 | got_tlsdesc_section() const |
| 531 | { |
| 532 | gold_assert(this->got_tlsdesc_ != NULL); |
| 533 | return this->got_tlsdesc_; |
| 534 | } |
| 535 | |
| 536 | // Create the PLT section. |
| 537 | void |
| 538 | make_plt_section(Symbol_table* symtab, Layout* layout); |
| 539 | |
| 540 | // Create a PLT entry for a global symbol. |
| 541 | void |
| 542 | make_plt_entry(Symbol_table*, Layout*, Symbol*); |
| 543 | |
| 544 | // Create a PLT entry for a local STT_GNU_IFUNC symbol. |
| 545 | void |
| 546 | make_local_ifunc_plt_entry(Symbol_table*, Layout*, |
| 547 | Sized_relobj<32, false>* relobj, |
| 548 | unsigned int local_sym_index); |
| 549 | |
| 550 | // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| 551 | void |
| 552 | define_tls_base_symbol(Symbol_table*, Layout*); |
| 553 | |
| 554 | // Create a GOT entry for the TLS module index. |
| 555 | unsigned int |
| 556 | got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| 557 | Sized_relobj<32, false>* object); |
| 558 | |
| 559 | // Get the PLT section. |
| 560 | Output_data_plt_i386* |
| 561 | plt_section() const |
| 562 | { |
| 563 | gold_assert(this->plt_ != NULL); |
| 564 | return this->plt_; |
| 565 | } |
| 566 | |
| 567 | // Get the dynamic reloc section, creating it if necessary. |
| 568 | Reloc_section* |
| 569 | rel_dyn_section(Layout*); |
| 570 | |
| 571 | // Get the section to use for TLS_DESC relocations. |
| 572 | Reloc_section* |
| 573 | rel_tls_desc_section(Layout*) const; |
| 574 | |
| 575 | // Add a potential copy relocation. |
| 576 | void |
| 577 | copy_reloc(Symbol_table* symtab, Layout* layout, |
| 578 | Sized_relobj<32, false>* object, |
| 579 | unsigned int shndx, Output_section* output_section, |
| 580 | Symbol* sym, const elfcpp::Rel<32, false>& reloc) |
| 581 | { |
| 582 | this->copy_relocs_.copy_reloc(symtab, layout, |
| 583 | symtab->get_sized_symbol<32>(sym), |
| 584 | object, shndx, output_section, reloc, |
| 585 | this->rel_dyn_section(layout)); |
| 586 | } |
| 587 | |
| 588 | // Information about this specific target which we pass to the |
| 589 | // general Target structure. |
| 590 | static const Target::Target_info i386_info; |
| 591 | |
| 592 | // The types of GOT entries needed for this platform. |
| 593 | // These values are exposed to the ABI in an incremental link. |
| 594 | // Do not renumber existing values without changing the version |
| 595 | // number of the .gnu_incremental_inputs section. |
| 596 | enum Got_type |
| 597 | { |
| 598 | GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol |
| 599 | GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset |
| 600 | GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset |
| 601 | GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair |
| 602 | GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair |
| 603 | }; |
| 604 | |
| 605 | // The GOT section. |
| 606 | Output_data_got<32, false>* got_; |
| 607 | // The PLT section. |
| 608 | Output_data_plt_i386* plt_; |
| 609 | // The GOT PLT section. |
| 610 | Output_data_space* got_plt_; |
| 611 | // The GOT section for TLSDESC relocations. |
| 612 | Output_data_got<32, false>* got_tlsdesc_; |
| 613 | // The _GLOBAL_OFFSET_TABLE_ symbol. |
| 614 | Symbol* global_offset_table_; |
| 615 | // The dynamic reloc section. |
| 616 | Reloc_section* rel_dyn_; |
| 617 | // Relocs saved to avoid a COPY reloc. |
| 618 | Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_; |
| 619 | // Space for variables copied with a COPY reloc. |
| 620 | Output_data_space* dynbss_; |
| 621 | // Offset of the GOT entry for the TLS module index. |
| 622 | unsigned int got_mod_index_offset_; |
| 623 | // True if the _TLS_MODULE_BASE_ symbol has been defined. |
| 624 | bool tls_base_symbol_defined_; |
| 625 | }; |
| 626 | |
| 627 | const Target::Target_info Target_i386::i386_info = |
| 628 | { |
| 629 | 32, // size |
| 630 | false, // is_big_endian |
| 631 | elfcpp::EM_386, // machine_code |
| 632 | false, // has_make_symbol |
| 633 | false, // has_resolve |
| 634 | true, // has_code_fill |
| 635 | true, // is_default_stack_executable |
| 636 | '\0', // wrap_char |
| 637 | "/usr/lib/libc.so.1", // dynamic_linker |
| 638 | 0x08048000, // default_text_segment_address |
| 639 | 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 640 | 0x1000, // common_pagesize (overridable by -z common-page-size) |
| 641 | elfcpp::SHN_UNDEF, // small_common_shndx |
| 642 | elfcpp::SHN_UNDEF, // large_common_shndx |
| 643 | 0, // small_common_section_flags |
| 644 | 0, // large_common_section_flags |
| 645 | NULL, // attributes_section |
| 646 | NULL // attributes_vendor |
| 647 | }; |
| 648 | |
| 649 | // Get the GOT section, creating it if necessary. |
| 650 | |
| 651 | Output_data_got<32, false>* |
| 652 | Target_i386::got_section(Symbol_table* symtab, Layout* layout) |
| 653 | { |
| 654 | if (this->got_ == NULL) |
| 655 | { |
| 656 | gold_assert(symtab != NULL && layout != NULL); |
| 657 | |
| 658 | this->got_ = new Output_data_got<32, false>(); |
| 659 | |
| 660 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| 661 | (elfcpp::SHF_ALLOC |
| 662 | | elfcpp::SHF_WRITE), |
| 663 | this->got_, ORDER_RELRO_LAST, true); |
| 664 | |
| 665 | this->got_plt_ = new Output_data_space(4, "** GOT PLT"); |
| 666 | layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| 667 | (elfcpp::SHF_ALLOC |
| 668 | | elfcpp::SHF_WRITE), |
| 669 | this->got_plt_, ORDER_NON_RELRO_FIRST, |
| 670 | false); |
| 671 | |
| 672 | // The first three entries are reserved. |
| 673 | this->got_plt_->set_current_data_size(3 * 4); |
| 674 | |
| 675 | // Those bytes can go into the relro segment. |
| 676 | layout->increase_relro(3 * 4); |
| 677 | |
| 678 | // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| 679 | this->global_offset_table_ = |
| 680 | symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| 681 | Symbol_table::PREDEFINED, |
| 682 | this->got_plt_, |
| 683 | 0, 0, elfcpp::STT_OBJECT, |
| 684 | elfcpp::STB_LOCAL, |
| 685 | elfcpp::STV_HIDDEN, 0, |
| 686 | false, false); |
| 687 | |
| 688 | // If there are any TLSDESC relocations, they get GOT entries in |
| 689 | // .got.plt after the jump slot entries. |
| 690 | this->got_tlsdesc_ = new Output_data_got<32, false>(); |
| 691 | layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| 692 | (elfcpp::SHF_ALLOC |
| 693 | | elfcpp::SHF_WRITE), |
| 694 | this->got_tlsdesc_, |
| 695 | ORDER_NON_RELRO_FIRST, false); |
| 696 | } |
| 697 | |
| 698 | return this->got_; |
| 699 | } |
| 700 | |
| 701 | // Get the dynamic reloc section, creating it if necessary. |
| 702 | |
| 703 | Target_i386::Reloc_section* |
| 704 | Target_i386::rel_dyn_section(Layout* layout) |
| 705 | { |
| 706 | if (this->rel_dyn_ == NULL) |
| 707 | { |
| 708 | gold_assert(layout != NULL); |
| 709 | this->rel_dyn_ = new Reloc_section(parameters->options().combreloc()); |
| 710 | layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| 711 | elfcpp::SHF_ALLOC, this->rel_dyn_, |
| 712 | ORDER_DYNAMIC_RELOCS, false); |
| 713 | } |
| 714 | return this->rel_dyn_; |
| 715 | } |
| 716 | |
| 717 | // Create the PLT section. The ordinary .got section is an argument, |
| 718 | // since we need to refer to the start. We also create our own .got |
| 719 | // section just for PLT entries. |
| 720 | |
| 721 | Output_data_plt_i386::Output_data_plt_i386(Symbol_table* symtab, |
| 722 | Layout* layout, |
| 723 | Output_data_space* got_plt) |
| 724 | : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0), |
| 725 | global_ifuncs_(), local_ifuncs_() |
| 726 | { |
| 727 | this->rel_ = new Reloc_section(false); |
| 728 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 729 | elfcpp::SHF_ALLOC, this->rel_, |
| 730 | ORDER_DYNAMIC_PLT_RELOCS, false); |
| 731 | |
| 732 | if (parameters->doing_static_link()) |
| 733 | { |
| 734 | // A statically linked executable will only have a .rel.plt |
| 735 | // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC |
| 736 | // symbols. The library will use these symbols to locate the |
| 737 | // IRELATIVE relocs at program startup time. |
| 738 | symtab->define_in_output_data("__rel_iplt_start", NULL, |
| 739 | Symbol_table::PREDEFINED, |
| 740 | this->rel_, 0, 0, elfcpp::STT_NOTYPE, |
| 741 | elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, |
| 742 | 0, false, true); |
| 743 | symtab->define_in_output_data("__rel_iplt_end", NULL, |
| 744 | Symbol_table::PREDEFINED, |
| 745 | this->rel_, 0, 0, elfcpp::STT_NOTYPE, |
| 746 | elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, |
| 747 | 0, true, true); |
| 748 | } |
| 749 | } |
| 750 | |
| 751 | void |
| 752 | Output_data_plt_i386::do_adjust_output_section(Output_section* os) |
| 753 | { |
| 754 | // UnixWare sets the entsize of .plt to 4, and so does the old GNU |
| 755 | // linker, and so do we. |
| 756 | os->set_entsize(4); |
| 757 | } |
| 758 | |
| 759 | // Add an entry to the PLT. |
| 760 | |
| 761 | void |
| 762 | Output_data_plt_i386::add_entry(Symbol* gsym) |
| 763 | { |
| 764 | gold_assert(!gsym->has_plt_offset()); |
| 765 | |
| 766 | // Note that when setting the PLT offset we skip the initial |
| 767 | // reserved PLT entry. |
| 768 | gsym->set_plt_offset((this->count_ + 1) * plt_entry_size); |
| 769 | |
| 770 | ++this->count_; |
| 771 | |
| 772 | section_offset_type got_offset = this->got_plt_->current_data_size(); |
| 773 | |
| 774 | // Every PLT entry needs a GOT entry which points back to the PLT |
| 775 | // entry (this will be changed by the dynamic linker, normally |
| 776 | // lazily when the function is called). |
| 777 | this->got_plt_->set_current_data_size(got_offset + 4); |
| 778 | |
| 779 | // Every PLT entry needs a reloc. |
| 780 | if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 781 | && gsym->can_use_relative_reloc(false)) |
| 782 | { |
| 783 | this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE, |
| 784 | this->got_plt_, got_offset); |
| 785 | struct Global_ifunc gi; |
| 786 | gi.sym = gsym; |
| 787 | gi.got_offset = got_offset; |
| 788 | this->global_ifuncs_.push_back(gi); |
| 789 | } |
| 790 | else |
| 791 | { |
| 792 | gsym->set_needs_dynsym_entry(); |
| 793 | this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_, |
| 794 | got_offset); |
| 795 | } |
| 796 | |
| 797 | // Note that we don't need to save the symbol. The contents of the |
| 798 | // PLT are independent of which symbols are used. The symbols only |
| 799 | // appear in the relocations. |
| 800 | } |
| 801 | |
| 802 | // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return |
| 803 | // the PLT offset. |
| 804 | |
| 805 | unsigned int |
| 806 | Output_data_plt_i386::add_local_ifunc_entry(Sized_relobj<32, false>* relobj, |
| 807 | unsigned int local_sym_index) |
| 808 | { |
| 809 | unsigned int plt_offset = (this->count_ + 1) * plt_entry_size; |
| 810 | ++this->count_; |
| 811 | |
| 812 | section_offset_type got_offset = this->got_plt_->current_data_size(); |
| 813 | |
| 814 | // Every PLT entry needs a GOT entry which points back to the PLT |
| 815 | // entry. |
| 816 | this->got_plt_->set_current_data_size(got_offset + 4); |
| 817 | |
| 818 | // Every PLT entry needs a reloc. |
| 819 | this->rel_->add_symbolless_local_addend(relobj, local_sym_index, |
| 820 | elfcpp::R_386_IRELATIVE, |
| 821 | this->got_plt_, got_offset); |
| 822 | |
| 823 | struct Local_ifunc li; |
| 824 | li.object = relobj; |
| 825 | li.local_sym_index = local_sym_index; |
| 826 | li.got_offset = got_offset; |
| 827 | this->local_ifuncs_.push_back(li); |
| 828 | |
| 829 | return plt_offset; |
| 830 | } |
| 831 | |
| 832 | // Return where the TLS_DESC relocations should go, creating it if |
| 833 | // necessary. These follow the JUMP_SLOT relocations. |
| 834 | |
| 835 | Output_data_plt_i386::Reloc_section* |
| 836 | Output_data_plt_i386::rel_tls_desc(Layout* layout) |
| 837 | { |
| 838 | if (this->tls_desc_rel_ == NULL) |
| 839 | { |
| 840 | this->tls_desc_rel_ = new Reloc_section(false); |
| 841 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 842 | elfcpp::SHF_ALLOC, this->tls_desc_rel_, |
| 843 | ORDER_DYNAMIC_PLT_RELOCS, false); |
| 844 | gold_assert(this->tls_desc_rel_->output_section() == |
| 845 | this->rel_->output_section()); |
| 846 | } |
| 847 | return this->tls_desc_rel_; |
| 848 | } |
| 849 | |
| 850 | // The first entry in the PLT for an executable. |
| 851 | |
| 852 | unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] = |
| 853 | { |
| 854 | 0xff, 0x35, // pushl contents of memory address |
| 855 | 0, 0, 0, 0, // replaced with address of .got + 4 |
| 856 | 0xff, 0x25, // jmp indirect |
| 857 | 0, 0, 0, 0, // replaced with address of .got + 8 |
| 858 | 0, 0, 0, 0 // unused |
| 859 | }; |
| 860 | |
| 861 | // The first entry in the PLT for a shared object. |
| 862 | |
| 863 | unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] = |
| 864 | { |
| 865 | 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 866 | 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) |
| 867 | 0, 0, 0, 0 // unused |
| 868 | }; |
| 869 | |
| 870 | // Subsequent entries in the PLT for an executable. |
| 871 | |
| 872 | unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] = |
| 873 | { |
| 874 | 0xff, 0x25, // jmp indirect |
| 875 | 0, 0, 0, 0, // replaced with address of symbol in .got |
| 876 | 0x68, // pushl immediate |
| 877 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 878 | 0xe9, // jmp relative |
| 879 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 880 | }; |
| 881 | |
| 882 | // Subsequent entries in the PLT for a shared object. |
| 883 | |
| 884 | unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] = |
| 885 | { |
| 886 | 0xff, 0xa3, // jmp *offset(%ebx) |
| 887 | 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 888 | 0x68, // pushl immediate |
| 889 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 890 | 0xe9, // jmp relative |
| 891 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 892 | }; |
| 893 | |
| 894 | // Write out the PLT. This uses the hand-coded instructions above, |
| 895 | // and adjusts them as needed. This is all specified by the i386 ELF |
| 896 | // Processor Supplement. |
| 897 | |
| 898 | void |
| 899 | Output_data_plt_i386::do_write(Output_file* of) |
| 900 | { |
| 901 | const off_t offset = this->offset(); |
| 902 | const section_size_type oview_size = |
| 903 | convert_to_section_size_type(this->data_size()); |
| 904 | unsigned char* const oview = of->get_output_view(offset, oview_size); |
| 905 | |
| 906 | const off_t got_file_offset = this->got_plt_->offset(); |
| 907 | const section_size_type got_size = |
| 908 | convert_to_section_size_type(this->got_plt_->data_size()); |
| 909 | unsigned char* const got_view = of->get_output_view(got_file_offset, |
| 910 | got_size); |
| 911 | |
| 912 | unsigned char* pov = oview; |
| 913 | |
| 914 | elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| 915 | elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| 916 | |
| 917 | if (parameters->options().output_is_position_independent()) |
| 918 | memcpy(pov, dyn_first_plt_entry, plt_entry_size); |
| 919 | else |
| 920 | { |
| 921 | memcpy(pov, exec_first_plt_entry, plt_entry_size); |
| 922 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| 923 | elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| 924 | } |
| 925 | pov += plt_entry_size; |
| 926 | |
| 927 | unsigned char* got_pov = got_view; |
| 928 | |
| 929 | memset(got_pov, 0, 12); |
| 930 | got_pov += 12; |
| 931 | |
| 932 | const int rel_size = elfcpp::Elf_sizes<32>::rel_size; |
| 933 | |
| 934 | unsigned int plt_offset = plt_entry_size; |
| 935 | unsigned int plt_rel_offset = 0; |
| 936 | unsigned int got_offset = 12; |
| 937 | const unsigned int count = this->count_; |
| 938 | for (unsigned int i = 0; |
| 939 | i < count; |
| 940 | ++i, |
| 941 | pov += plt_entry_size, |
| 942 | got_pov += 4, |
| 943 | plt_offset += plt_entry_size, |
| 944 | plt_rel_offset += rel_size, |
| 945 | got_offset += 4) |
| 946 | { |
| 947 | // Set and adjust the PLT entry itself. |
| 948 | |
| 949 | if (parameters->options().output_is_position_independent()) |
| 950 | { |
| 951 | memcpy(pov, dyn_plt_entry, plt_entry_size); |
| 952 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| 953 | } |
| 954 | else |
| 955 | { |
| 956 | memcpy(pov, exec_plt_entry, plt_entry_size); |
| 957 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| 958 | (got_address |
| 959 | + got_offset)); |
| 960 | } |
| 961 | |
| 962 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| 963 | elfcpp::Swap<32, false>::writeval(pov + 12, |
| 964 | - (plt_offset + plt_entry_size)); |
| 965 | |
| 966 | // Set the entry in the GOT. |
| 967 | elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6); |
| 968 | } |
| 969 | |
| 970 | // If any STT_GNU_IFUNC symbols have PLT entries, we need to change |
| 971 | // the GOT to point to the actual symbol value, rather than point to |
| 972 | // the PLT entry. That will let the dynamic linker call the right |
| 973 | // function when resolving IRELATIVE relocations. |
| 974 | for (std::vector<Global_ifunc>::const_iterator p = |
| 975 | this->global_ifuncs_.begin(); |
| 976 | p != this->global_ifuncs_.end(); |
| 977 | ++p) |
| 978 | { |
| 979 | const Sized_symbol<32>* ssym = |
| 980 | static_cast<const Sized_symbol<32>*>(p->sym); |
| 981 | elfcpp::Swap<32, false>::writeval(got_view + p->got_offset, |
| 982 | ssym->value()); |
| 983 | } |
| 984 | |
| 985 | for (std::vector<Local_ifunc>::const_iterator p = |
| 986 | this->local_ifuncs_.begin(); |
| 987 | p != this->local_ifuncs_.end(); |
| 988 | ++p) |
| 989 | { |
| 990 | const Symbol_value<32>* psymval = |
| 991 | p->object->local_symbol(p->local_sym_index); |
| 992 | elfcpp::Swap<32, false>::writeval(got_view + p->got_offset, |
| 993 | psymval->value(p->object, 0)); |
| 994 | } |
| 995 | |
| 996 | gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| 997 | gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| 998 | |
| 999 | of->write_output_view(offset, oview_size, oview); |
| 1000 | of->write_output_view(got_file_offset, got_size, got_view); |
| 1001 | } |
| 1002 | |
| 1003 | // Create the PLT section. |
| 1004 | |
| 1005 | void |
| 1006 | Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout) |
| 1007 | { |
| 1008 | if (this->plt_ == NULL) |
| 1009 | { |
| 1010 | // Create the GOT sections first. |
| 1011 | this->got_section(symtab, layout); |
| 1012 | |
| 1013 | this->plt_ = new Output_data_plt_i386(symtab, layout, this->got_plt_); |
| 1014 | layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| 1015 | (elfcpp::SHF_ALLOC |
| 1016 | | elfcpp::SHF_EXECINSTR), |
| 1017 | this->plt_, ORDER_PLT, false); |
| 1018 | |
| 1019 | // Make the sh_info field of .rel.plt point to .plt. |
| 1020 | Output_section* rel_plt_os = this->plt_->rel_plt()->output_section(); |
| 1021 | rel_plt_os->set_info_section(this->plt_->output_section()); |
| 1022 | } |
| 1023 | } |
| 1024 | |
| 1025 | // Create a PLT entry for a global symbol. |
| 1026 | |
| 1027 | void |
| 1028 | Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym) |
| 1029 | { |
| 1030 | if (gsym->has_plt_offset()) |
| 1031 | return; |
| 1032 | if (this->plt_ == NULL) |
| 1033 | this->make_plt_section(symtab, layout); |
| 1034 | this->plt_->add_entry(gsym); |
| 1035 | } |
| 1036 | |
| 1037 | // Make a PLT entry for a local STT_GNU_IFUNC symbol. |
| 1038 | |
| 1039 | void |
| 1040 | Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, |
| 1041 | Sized_relobj<32, false>* relobj, |
| 1042 | unsigned int local_sym_index) |
| 1043 | { |
| 1044 | if (relobj->local_has_plt_offset(local_sym_index)) |
| 1045 | return; |
| 1046 | if (this->plt_ == NULL) |
| 1047 | this->make_plt_section(symtab, layout); |
| 1048 | unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj, |
| 1049 | local_sym_index); |
| 1050 | relobj->set_local_plt_offset(local_sym_index, plt_offset); |
| 1051 | } |
| 1052 | |
| 1053 | // Return the number of entries in the PLT. |
| 1054 | |
| 1055 | unsigned int |
| 1056 | Target_i386::plt_entry_count() const |
| 1057 | { |
| 1058 | if (this->plt_ == NULL) |
| 1059 | return 0; |
| 1060 | return this->plt_->entry_count(); |
| 1061 | } |
| 1062 | |
| 1063 | // Return the offset of the first non-reserved PLT entry. |
| 1064 | |
| 1065 | unsigned int |
| 1066 | Target_i386::first_plt_entry_offset() const |
| 1067 | { |
| 1068 | return Output_data_plt_i386::first_plt_entry_offset(); |
| 1069 | } |
| 1070 | |
| 1071 | // Return the size of each PLT entry. |
| 1072 | |
| 1073 | unsigned int |
| 1074 | Target_i386::plt_entry_size() const |
| 1075 | { |
| 1076 | return Output_data_plt_i386::get_plt_entry_size(); |
| 1077 | } |
| 1078 | |
| 1079 | // Get the section to use for TLS_DESC relocations. |
| 1080 | |
| 1081 | Target_i386::Reloc_section* |
| 1082 | Target_i386::rel_tls_desc_section(Layout* layout) const |
| 1083 | { |
| 1084 | return this->plt_section()->rel_tls_desc(layout); |
| 1085 | } |
| 1086 | |
| 1087 | // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| 1088 | |
| 1089 | void |
| 1090 | Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) |
| 1091 | { |
| 1092 | if (this->tls_base_symbol_defined_) |
| 1093 | return; |
| 1094 | |
| 1095 | Output_segment* tls_segment = layout->tls_segment(); |
| 1096 | if (tls_segment != NULL) |
| 1097 | { |
| 1098 | bool is_exec = parameters->options().output_is_executable(); |
| 1099 | symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, |
| 1100 | Symbol_table::PREDEFINED, |
| 1101 | tls_segment, 0, 0, |
| 1102 | elfcpp::STT_TLS, |
| 1103 | elfcpp::STB_LOCAL, |
| 1104 | elfcpp::STV_HIDDEN, 0, |
| 1105 | (is_exec |
| 1106 | ? Symbol::SEGMENT_END |
| 1107 | : Symbol::SEGMENT_START), |
| 1108 | true); |
| 1109 | } |
| 1110 | this->tls_base_symbol_defined_ = true; |
| 1111 | } |
| 1112 | |
| 1113 | // Create a GOT entry for the TLS module index. |
| 1114 | |
| 1115 | unsigned int |
| 1116 | Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| 1117 | Sized_relobj<32, false>* object) |
| 1118 | { |
| 1119 | if (this->got_mod_index_offset_ == -1U) |
| 1120 | { |
| 1121 | gold_assert(symtab != NULL && layout != NULL && object != NULL); |
| 1122 | Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| 1123 | Output_data_got<32, false>* got = this->got_section(symtab, layout); |
| 1124 | unsigned int got_offset = got->add_constant(0); |
| 1125 | rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got, |
| 1126 | got_offset); |
| 1127 | got->add_constant(0); |
| 1128 | this->got_mod_index_offset_ = got_offset; |
| 1129 | } |
| 1130 | return this->got_mod_index_offset_; |
| 1131 | } |
| 1132 | |
| 1133 | // Optimize the TLS relocation type based on what we know about the |
| 1134 | // symbol. IS_FINAL is true if the final address of this symbol is |
| 1135 | // known at link time. |
| 1136 | |
| 1137 | tls::Tls_optimization |
| 1138 | Target_i386::optimize_tls_reloc(bool is_final, int r_type) |
| 1139 | { |
| 1140 | // If we are generating a shared library, then we can't do anything |
| 1141 | // in the linker. |
| 1142 | if (parameters->options().shared()) |
| 1143 | return tls::TLSOPT_NONE; |
| 1144 | |
| 1145 | switch (r_type) |
| 1146 | { |
| 1147 | case elfcpp::R_386_TLS_GD: |
| 1148 | case elfcpp::R_386_TLS_GOTDESC: |
| 1149 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1150 | // These are General-Dynamic which permits fully general TLS |
| 1151 | // access. Since we know that we are generating an executable, |
| 1152 | // we can convert this to Initial-Exec. If we also know that |
| 1153 | // this is a local symbol, we can further switch to Local-Exec. |
| 1154 | if (is_final) |
| 1155 | return tls::TLSOPT_TO_LE; |
| 1156 | return tls::TLSOPT_TO_IE; |
| 1157 | |
| 1158 | case elfcpp::R_386_TLS_LDM: |
| 1159 | // This is Local-Dynamic, which refers to a local symbol in the |
| 1160 | // dynamic TLS block. Since we know that we generating an |
| 1161 | // executable, we can switch to Local-Exec. |
| 1162 | return tls::TLSOPT_TO_LE; |
| 1163 | |
| 1164 | case elfcpp::R_386_TLS_LDO_32: |
| 1165 | // Another type of Local-Dynamic relocation. |
| 1166 | return tls::TLSOPT_TO_LE; |
| 1167 | |
| 1168 | case elfcpp::R_386_TLS_IE: |
| 1169 | case elfcpp::R_386_TLS_GOTIE: |
| 1170 | case elfcpp::R_386_TLS_IE_32: |
| 1171 | // These are Initial-Exec relocs which get the thread offset |
| 1172 | // from the GOT. If we know that we are linking against the |
| 1173 | // local symbol, we can switch to Local-Exec, which links the |
| 1174 | // thread offset into the instruction. |
| 1175 | if (is_final) |
| 1176 | return tls::TLSOPT_TO_LE; |
| 1177 | return tls::TLSOPT_NONE; |
| 1178 | |
| 1179 | case elfcpp::R_386_TLS_LE: |
| 1180 | case elfcpp::R_386_TLS_LE_32: |
| 1181 | // When we already have Local-Exec, there is nothing further we |
| 1182 | // can do. |
| 1183 | return tls::TLSOPT_NONE; |
| 1184 | |
| 1185 | default: |
| 1186 | gold_unreachable(); |
| 1187 | } |
| 1188 | } |
| 1189 | |
| 1190 | // Report an unsupported relocation against a local symbol. |
| 1191 | |
| 1192 | void |
| 1193 | Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object, |
| 1194 | unsigned int r_type) |
| 1195 | { |
| 1196 | gold_error(_("%s: unsupported reloc %u against local symbol"), |
| 1197 | object->name().c_str(), r_type); |
| 1198 | } |
| 1199 | |
| 1200 | // Return whether we need to make a PLT entry for a relocation of a |
| 1201 | // given type against a STT_GNU_IFUNC symbol. |
| 1202 | |
| 1203 | bool |
| 1204 | Target_i386::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<32, false>* object, |
| 1205 | unsigned int r_type) |
| 1206 | { |
| 1207 | switch (r_type) |
| 1208 | { |
| 1209 | case elfcpp::R_386_NONE: |
| 1210 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1211 | case elfcpp::R_386_GNU_VTENTRY: |
| 1212 | return false; |
| 1213 | |
| 1214 | case elfcpp::R_386_32: |
| 1215 | case elfcpp::R_386_16: |
| 1216 | case elfcpp::R_386_8: |
| 1217 | case elfcpp::R_386_PC32: |
| 1218 | case elfcpp::R_386_PC16: |
| 1219 | case elfcpp::R_386_PC8: |
| 1220 | case elfcpp::R_386_PLT32: |
| 1221 | case elfcpp::R_386_GOTOFF: |
| 1222 | case elfcpp::R_386_GOTPC: |
| 1223 | case elfcpp::R_386_GOT32: |
| 1224 | return true; |
| 1225 | |
| 1226 | case elfcpp::R_386_COPY: |
| 1227 | case elfcpp::R_386_GLOB_DAT: |
| 1228 | case elfcpp::R_386_JUMP_SLOT: |
| 1229 | case elfcpp::R_386_RELATIVE: |
| 1230 | case elfcpp::R_386_IRELATIVE: |
| 1231 | case elfcpp::R_386_TLS_TPOFF: |
| 1232 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1233 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1234 | case elfcpp::R_386_TLS_TPOFF32: |
| 1235 | case elfcpp::R_386_TLS_DESC: |
| 1236 | // We will give an error later. |
| 1237 | return false; |
| 1238 | |
| 1239 | case elfcpp::R_386_TLS_GD: |
| 1240 | case elfcpp::R_386_TLS_GOTDESC: |
| 1241 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1242 | case elfcpp::R_386_TLS_LDM: |
| 1243 | case elfcpp::R_386_TLS_LDO_32: |
| 1244 | case elfcpp::R_386_TLS_IE: |
| 1245 | case elfcpp::R_386_TLS_IE_32: |
| 1246 | case elfcpp::R_386_TLS_GOTIE: |
| 1247 | case elfcpp::R_386_TLS_LE: |
| 1248 | case elfcpp::R_386_TLS_LE_32: |
| 1249 | gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), |
| 1250 | object->name().c_str(), r_type); |
| 1251 | return false; |
| 1252 | |
| 1253 | case elfcpp::R_386_32PLT: |
| 1254 | case elfcpp::R_386_TLS_GD_32: |
| 1255 | case elfcpp::R_386_TLS_GD_PUSH: |
| 1256 | case elfcpp::R_386_TLS_GD_CALL: |
| 1257 | case elfcpp::R_386_TLS_GD_POP: |
| 1258 | case elfcpp::R_386_TLS_LDM_32: |
| 1259 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 1260 | case elfcpp::R_386_TLS_LDM_CALL: |
| 1261 | case elfcpp::R_386_TLS_LDM_POP: |
| 1262 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 1263 | default: |
| 1264 | // We will give an error later. |
| 1265 | return false; |
| 1266 | } |
| 1267 | } |
| 1268 | |
| 1269 | // Scan a relocation for a local symbol. |
| 1270 | |
| 1271 | inline void |
| 1272 | Target_i386::Scan::local(Symbol_table* symtab, |
| 1273 | Layout* layout, |
| 1274 | Target_i386* target, |
| 1275 | Sized_relobj<32, false>* object, |
| 1276 | unsigned int data_shndx, |
| 1277 | Output_section* output_section, |
| 1278 | const elfcpp::Rel<32, false>& reloc, |
| 1279 | unsigned int r_type, |
| 1280 | const elfcpp::Sym<32, false>& lsym) |
| 1281 | { |
| 1282 | // A local STT_GNU_IFUNC symbol may require a PLT entry. |
| 1283 | if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC |
| 1284 | && this->reloc_needs_plt_for_ifunc(object, r_type)) |
| 1285 | { |
| 1286 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1287 | target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); |
| 1288 | } |
| 1289 | |
| 1290 | switch (r_type) |
| 1291 | { |
| 1292 | case elfcpp::R_386_NONE: |
| 1293 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1294 | case elfcpp::R_386_GNU_VTENTRY: |
| 1295 | break; |
| 1296 | |
| 1297 | case elfcpp::R_386_32: |
| 1298 | // If building a shared library (or a position-independent |
| 1299 | // executable), we need to create a dynamic relocation for |
| 1300 | // this location. The relocation applied at link time will |
| 1301 | // apply the link-time value, so we flag the location with |
| 1302 | // an R_386_RELATIVE relocation so the dynamic loader can |
| 1303 | // relocate it easily. |
| 1304 | if (parameters->options().output_is_position_independent()) |
| 1305 | { |
| 1306 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1307 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1308 | rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE, |
| 1309 | output_section, data_shndx, |
| 1310 | reloc.get_r_offset()); |
| 1311 | } |
| 1312 | break; |
| 1313 | |
| 1314 | case elfcpp::R_386_16: |
| 1315 | case elfcpp::R_386_8: |
| 1316 | // If building a shared library (or a position-independent |
| 1317 | // executable), we need to create a dynamic relocation for |
| 1318 | // this location. Because the addend needs to remain in the |
| 1319 | // data section, we need to be careful not to apply this |
| 1320 | // relocation statically. |
| 1321 | if (parameters->options().output_is_position_independent()) |
| 1322 | { |
| 1323 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1324 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1325 | if (lsym.get_st_type() != elfcpp::STT_SECTION) |
| 1326 | rel_dyn->add_local(object, r_sym, r_type, output_section, |
| 1327 | data_shndx, reloc.get_r_offset()); |
| 1328 | else |
| 1329 | { |
| 1330 | gold_assert(lsym.get_st_value() == 0); |
| 1331 | unsigned int shndx = lsym.get_st_shndx(); |
| 1332 | bool is_ordinary; |
| 1333 | shndx = object->adjust_sym_shndx(r_sym, shndx, |
| 1334 | &is_ordinary); |
| 1335 | if (!is_ordinary) |
| 1336 | object->error(_("section symbol %u has bad shndx %u"), |
| 1337 | r_sym, shndx); |
| 1338 | else |
| 1339 | rel_dyn->add_local_section(object, shndx, |
| 1340 | r_type, output_section, |
| 1341 | data_shndx, reloc.get_r_offset()); |
| 1342 | } |
| 1343 | } |
| 1344 | break; |
| 1345 | |
| 1346 | case elfcpp::R_386_PC32: |
| 1347 | case elfcpp::R_386_PC16: |
| 1348 | case elfcpp::R_386_PC8: |
| 1349 | break; |
| 1350 | |
| 1351 | case elfcpp::R_386_PLT32: |
| 1352 | // Since we know this is a local symbol, we can handle this as a |
| 1353 | // PC32 reloc. |
| 1354 | break; |
| 1355 | |
| 1356 | case elfcpp::R_386_GOTOFF: |
| 1357 | case elfcpp::R_386_GOTPC: |
| 1358 | // We need a GOT section. |
| 1359 | target->got_section(symtab, layout); |
| 1360 | break; |
| 1361 | |
| 1362 | case elfcpp::R_386_GOT32: |
| 1363 | { |
| 1364 | // The symbol requires a GOT entry. |
| 1365 | Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| 1366 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1367 | |
| 1368 | // For a STT_GNU_IFUNC symbol we want the PLT offset. That |
| 1369 | // lets function pointers compare correctly with shared |
| 1370 | // libraries. Otherwise we would need an IRELATIVE reloc. |
| 1371 | bool is_new; |
| 1372 | if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC) |
| 1373 | is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); |
| 1374 | else |
| 1375 | is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); |
| 1376 | if (is_new) |
| 1377 | { |
| 1378 | // If we are generating a shared object, we need to add a |
| 1379 | // dynamic RELATIVE relocation for this symbol's GOT entry. |
| 1380 | if (parameters->options().output_is_position_independent()) |
| 1381 | { |
| 1382 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1383 | unsigned int got_offset = |
| 1384 | object->local_got_offset(r_sym, GOT_TYPE_STANDARD); |
| 1385 | rel_dyn->add_local_relative(object, r_sym, |
| 1386 | elfcpp::R_386_RELATIVE, |
| 1387 | got, got_offset); |
| 1388 | } |
| 1389 | } |
| 1390 | } |
| 1391 | break; |
| 1392 | |
| 1393 | // These are relocations which should only be seen by the |
| 1394 | // dynamic linker, and should never be seen here. |
| 1395 | case elfcpp::R_386_COPY: |
| 1396 | case elfcpp::R_386_GLOB_DAT: |
| 1397 | case elfcpp::R_386_JUMP_SLOT: |
| 1398 | case elfcpp::R_386_RELATIVE: |
| 1399 | case elfcpp::R_386_IRELATIVE: |
| 1400 | case elfcpp::R_386_TLS_TPOFF: |
| 1401 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1402 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1403 | case elfcpp::R_386_TLS_TPOFF32: |
| 1404 | case elfcpp::R_386_TLS_DESC: |
| 1405 | gold_error(_("%s: unexpected reloc %u in object file"), |
| 1406 | object->name().c_str(), r_type); |
| 1407 | break; |
| 1408 | |
| 1409 | // These are initial TLS relocs, which are expected when |
| 1410 | // linking. |
| 1411 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1412 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 1413 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1414 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1415 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1416 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1417 | case elfcpp::R_386_TLS_IE_32: |
| 1418 | case elfcpp::R_386_TLS_GOTIE: |
| 1419 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1420 | case elfcpp::R_386_TLS_LE_32: |
| 1421 | { |
| 1422 | bool output_is_shared = parameters->options().shared(); |
| 1423 | const tls::Tls_optimization optimized_type |
| 1424 | = Target_i386::optimize_tls_reloc(!output_is_shared, r_type); |
| 1425 | switch (r_type) |
| 1426 | { |
| 1427 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1428 | if (optimized_type == tls::TLSOPT_NONE) |
| 1429 | { |
| 1430 | // Create a pair of GOT entries for the module index and |
| 1431 | // dtv-relative offset. |
| 1432 | Output_data_got<32, false>* got |
| 1433 | = target->got_section(symtab, layout); |
| 1434 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1435 | unsigned int shndx = lsym.get_st_shndx(); |
| 1436 | bool is_ordinary; |
| 1437 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); |
| 1438 | if (!is_ordinary) |
| 1439 | object->error(_("local symbol %u has bad shndx %u"), |
| 1440 | r_sym, shndx); |
| 1441 | else |
| 1442 | got->add_local_pair_with_rel(object, r_sym, shndx, |
| 1443 | GOT_TYPE_TLS_PAIR, |
| 1444 | target->rel_dyn_section(layout), |
| 1445 | elfcpp::R_386_TLS_DTPMOD32, 0); |
| 1446 | } |
| 1447 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1448 | unsupported_reloc_local(object, r_type); |
| 1449 | break; |
| 1450 | |
| 1451 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva) |
| 1452 | target->define_tls_base_symbol(symtab, layout); |
| 1453 | if (optimized_type == tls::TLSOPT_NONE) |
| 1454 | { |
| 1455 | // Create a double GOT entry with an R_386_TLS_DESC |
| 1456 | // reloc. The R_386_TLS_DESC reloc is resolved |
| 1457 | // lazily, so the GOT entry needs to be in an area in |
| 1458 | // .got.plt, not .got. Call got_section to make sure |
| 1459 | // the section has been created. |
| 1460 | target->got_section(symtab, layout); |
| 1461 | Output_data_got<32, false>* got = target->got_tlsdesc_section(); |
| 1462 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1463 | if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) |
| 1464 | { |
| 1465 | unsigned int got_offset = got->add_constant(0); |
| 1466 | // The local symbol value is stored in the second |
| 1467 | // GOT entry. |
| 1468 | got->add_local(object, r_sym, GOT_TYPE_TLS_DESC); |
| 1469 | // That set the GOT offset of the local symbol to |
| 1470 | // point to the second entry, but we want it to |
| 1471 | // point to the first. |
| 1472 | object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, |
| 1473 | got_offset); |
| 1474 | Reloc_section* rt = target->rel_tls_desc_section(layout); |
| 1475 | rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset); |
| 1476 | } |
| 1477 | } |
| 1478 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1479 | unsupported_reloc_local(object, r_type); |
| 1480 | break; |
| 1481 | |
| 1482 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1483 | break; |
| 1484 | |
| 1485 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1486 | if (optimized_type == tls::TLSOPT_NONE) |
| 1487 | { |
| 1488 | // Create a GOT entry for the module index. |
| 1489 | target->got_mod_index_entry(symtab, layout, object); |
| 1490 | } |
| 1491 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1492 | unsupported_reloc_local(object, r_type); |
| 1493 | break; |
| 1494 | |
| 1495 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1496 | break; |
| 1497 | |
| 1498 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1499 | case elfcpp::R_386_TLS_IE_32: |
| 1500 | case elfcpp::R_386_TLS_GOTIE: |
| 1501 | layout->set_has_static_tls(); |
| 1502 | if (optimized_type == tls::TLSOPT_NONE) |
| 1503 | { |
| 1504 | // For the R_386_TLS_IE relocation, we need to create a |
| 1505 | // dynamic relocation when building a shared library. |
| 1506 | if (r_type == elfcpp::R_386_TLS_IE |
| 1507 | && parameters->options().shared()) |
| 1508 | { |
| 1509 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1510 | unsigned int r_sym |
| 1511 | = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1512 | rel_dyn->add_local_relative(object, r_sym, |
| 1513 | elfcpp::R_386_RELATIVE, |
| 1514 | output_section, data_shndx, |
| 1515 | reloc.get_r_offset()); |
| 1516 | } |
| 1517 | // Create a GOT entry for the tp-relative offset. |
| 1518 | Output_data_got<32, false>* got |
| 1519 | = target->got_section(symtab, layout); |
| 1520 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1521 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1522 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1523 | : elfcpp::R_386_TLS_TPOFF); |
| 1524 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1525 | ? GOT_TYPE_TLS_OFFSET |
| 1526 | : GOT_TYPE_TLS_NOFFSET); |
| 1527 | got->add_local_with_rel(object, r_sym, got_type, |
| 1528 | target->rel_dyn_section(layout), |
| 1529 | dyn_r_type); |
| 1530 | } |
| 1531 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1532 | unsupported_reloc_local(object, r_type); |
| 1533 | break; |
| 1534 | |
| 1535 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1536 | case elfcpp::R_386_TLS_LE_32: |
| 1537 | layout->set_has_static_tls(); |
| 1538 | if (output_is_shared) |
| 1539 | { |
| 1540 | // We need to create a dynamic relocation. |
| 1541 | gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); |
| 1542 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1543 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| 1544 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1545 | : elfcpp::R_386_TLS_TPOFF); |
| 1546 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1547 | rel_dyn->add_local(object, r_sym, dyn_r_type, output_section, |
| 1548 | data_shndx, reloc.get_r_offset()); |
| 1549 | } |
| 1550 | break; |
| 1551 | |
| 1552 | default: |
| 1553 | gold_unreachable(); |
| 1554 | } |
| 1555 | } |
| 1556 | break; |
| 1557 | |
| 1558 | case elfcpp::R_386_32PLT: |
| 1559 | case elfcpp::R_386_TLS_GD_32: |
| 1560 | case elfcpp::R_386_TLS_GD_PUSH: |
| 1561 | case elfcpp::R_386_TLS_GD_CALL: |
| 1562 | case elfcpp::R_386_TLS_GD_POP: |
| 1563 | case elfcpp::R_386_TLS_LDM_32: |
| 1564 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 1565 | case elfcpp::R_386_TLS_LDM_CALL: |
| 1566 | case elfcpp::R_386_TLS_LDM_POP: |
| 1567 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 1568 | default: |
| 1569 | unsupported_reloc_local(object, r_type); |
| 1570 | break; |
| 1571 | } |
| 1572 | } |
| 1573 | |
| 1574 | // Report an unsupported relocation against a global symbol. |
| 1575 | |
| 1576 | void |
| 1577 | Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object, |
| 1578 | unsigned int r_type, |
| 1579 | Symbol* gsym) |
| 1580 | { |
| 1581 | gold_error(_("%s: unsupported reloc %u against global symbol %s"), |
| 1582 | object->name().c_str(), r_type, gsym->demangled_name().c_str()); |
| 1583 | } |
| 1584 | |
| 1585 | inline bool |
| 1586 | Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type) |
| 1587 | { |
| 1588 | switch (r_type) |
| 1589 | { |
| 1590 | case elfcpp::R_386_32: |
| 1591 | case elfcpp::R_386_16: |
| 1592 | case elfcpp::R_386_8: |
| 1593 | case elfcpp::R_386_GOTOFF: |
| 1594 | case elfcpp::R_386_GOT32: |
| 1595 | { |
| 1596 | return true; |
| 1597 | } |
| 1598 | default: |
| 1599 | return false; |
| 1600 | } |
| 1601 | return false; |
| 1602 | } |
| 1603 | |
| 1604 | inline bool |
| 1605 | Target_i386::Scan::local_reloc_may_be_function_pointer( |
| 1606 | Symbol_table* , |
| 1607 | Layout* , |
| 1608 | Target_i386* , |
| 1609 | Sized_relobj<32, false>* , |
| 1610 | unsigned int , |
| 1611 | Output_section* , |
| 1612 | const elfcpp::Rel<32, false>& , |
| 1613 | unsigned int r_type, |
| 1614 | const elfcpp::Sym<32, false>&) |
| 1615 | { |
| 1616 | return possible_function_pointer_reloc(r_type); |
| 1617 | } |
| 1618 | |
| 1619 | inline bool |
| 1620 | Target_i386::Scan::global_reloc_may_be_function_pointer( |
| 1621 | Symbol_table* , |
| 1622 | Layout* , |
| 1623 | Target_i386* , |
| 1624 | Sized_relobj<32, false>* , |
| 1625 | unsigned int , |
| 1626 | Output_section* , |
| 1627 | const elfcpp::Rel<32, false>& , |
| 1628 | unsigned int r_type, |
| 1629 | Symbol*) |
| 1630 | { |
| 1631 | return possible_function_pointer_reloc(r_type); |
| 1632 | } |
| 1633 | |
| 1634 | // Scan a relocation for a global symbol. |
| 1635 | |
| 1636 | inline void |
| 1637 | Target_i386::Scan::global(Symbol_table* symtab, |
| 1638 | Layout* layout, |
| 1639 | Target_i386* target, |
| 1640 | Sized_relobj<32, false>* object, |
| 1641 | unsigned int data_shndx, |
| 1642 | Output_section* output_section, |
| 1643 | const elfcpp::Rel<32, false>& reloc, |
| 1644 | unsigned int r_type, |
| 1645 | Symbol* gsym) |
| 1646 | { |
| 1647 | // A STT_GNU_IFUNC symbol may require a PLT entry. |
| 1648 | if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 1649 | && this->reloc_needs_plt_for_ifunc(object, r_type)) |
| 1650 | target->make_plt_entry(symtab, layout, gsym); |
| 1651 | |
| 1652 | switch (r_type) |
| 1653 | { |
| 1654 | case elfcpp::R_386_NONE: |
| 1655 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1656 | case elfcpp::R_386_GNU_VTENTRY: |
| 1657 | break; |
| 1658 | |
| 1659 | case elfcpp::R_386_32: |
| 1660 | case elfcpp::R_386_16: |
| 1661 | case elfcpp::R_386_8: |
| 1662 | { |
| 1663 | // Make a PLT entry if necessary. |
| 1664 | if (gsym->needs_plt_entry()) |
| 1665 | { |
| 1666 | target->make_plt_entry(symtab, layout, gsym); |
| 1667 | // Since this is not a PC-relative relocation, we may be |
| 1668 | // taking the address of a function. In that case we need to |
| 1669 | // set the entry in the dynamic symbol table to the address of |
| 1670 | // the PLT entry. |
| 1671 | if (gsym->is_from_dynobj() && !parameters->options().shared()) |
| 1672 | gsym->set_needs_dynsym_value(); |
| 1673 | } |
| 1674 | // Make a dynamic relocation if necessary. |
| 1675 | if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) |
| 1676 | { |
| 1677 | if (gsym->may_need_copy_reloc()) |
| 1678 | { |
| 1679 | target->copy_reloc(symtab, layout, object, |
| 1680 | data_shndx, output_section, gsym, reloc); |
| 1681 | } |
| 1682 | else if (r_type == elfcpp::R_386_32 |
| 1683 | && gsym->type() == elfcpp::STT_GNU_IFUNC |
| 1684 | && gsym->can_use_relative_reloc(false) |
| 1685 | && !gsym->is_from_dynobj() |
| 1686 | && !gsym->is_undefined() |
| 1687 | && !gsym->is_preemptible()) |
| 1688 | { |
| 1689 | // Use an IRELATIVE reloc for a locally defined |
| 1690 | // STT_GNU_IFUNC symbol. This makes a function |
| 1691 | // address in a PIE executable match the address in a |
| 1692 | // shared library that it links against. |
| 1693 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1694 | rel_dyn->add_symbolless_global_addend(gsym, |
| 1695 | elfcpp::R_386_IRELATIVE, |
| 1696 | output_section, |
| 1697 | object, data_shndx, |
| 1698 | reloc.get_r_offset()); |
| 1699 | } |
| 1700 | else if (r_type == elfcpp::R_386_32 |
| 1701 | && gsym->can_use_relative_reloc(false)) |
| 1702 | { |
| 1703 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1704 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 1705 | output_section, object, |
| 1706 | data_shndx, reloc.get_r_offset()); |
| 1707 | } |
| 1708 | else |
| 1709 | { |
| 1710 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1711 | rel_dyn->add_global(gsym, r_type, output_section, object, |
| 1712 | data_shndx, reloc.get_r_offset()); |
| 1713 | } |
| 1714 | } |
| 1715 | } |
| 1716 | break; |
| 1717 | |
| 1718 | case elfcpp::R_386_PC32: |
| 1719 | case elfcpp::R_386_PC16: |
| 1720 | case elfcpp::R_386_PC8: |
| 1721 | { |
| 1722 | // Make a PLT entry if necessary. |
| 1723 | if (gsym->needs_plt_entry()) |
| 1724 | { |
| 1725 | // These relocations are used for function calls only in |
| 1726 | // non-PIC code. For a 32-bit relocation in a shared library, |
| 1727 | // we'll need a text relocation anyway, so we can skip the |
| 1728 | // PLT entry and let the dynamic linker bind the call directly |
| 1729 | // to the target. For smaller relocations, we should use a |
| 1730 | // PLT entry to ensure that the call can reach. |
| 1731 | if (!parameters->options().shared() |
| 1732 | || r_type != elfcpp::R_386_PC32) |
| 1733 | target->make_plt_entry(symtab, layout, gsym); |
| 1734 | } |
| 1735 | // Make a dynamic relocation if necessary. |
| 1736 | int flags = Symbol::NON_PIC_REF; |
| 1737 | if (gsym->is_func()) |
| 1738 | flags |= Symbol::FUNCTION_CALL; |
| 1739 | if (gsym->needs_dynamic_reloc(flags)) |
| 1740 | { |
| 1741 | if (gsym->may_need_copy_reloc()) |
| 1742 | { |
| 1743 | target->copy_reloc(symtab, layout, object, |
| 1744 | data_shndx, output_section, gsym, reloc); |
| 1745 | } |
| 1746 | else |
| 1747 | { |
| 1748 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1749 | rel_dyn->add_global(gsym, r_type, output_section, object, |
| 1750 | data_shndx, reloc.get_r_offset()); |
| 1751 | } |
| 1752 | } |
| 1753 | } |
| 1754 | break; |
| 1755 | |
| 1756 | case elfcpp::R_386_GOT32: |
| 1757 | { |
| 1758 | // The symbol requires a GOT entry. |
| 1759 | Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| 1760 | if (gsym->final_value_is_known()) |
| 1761 | { |
| 1762 | // For a STT_GNU_IFUNC symbol we want the PLT address. |
| 1763 | if (gsym->type() == elfcpp::STT_GNU_IFUNC) |
| 1764 | got->add_global_plt(gsym, GOT_TYPE_STANDARD); |
| 1765 | else |
| 1766 | got->add_global(gsym, GOT_TYPE_STANDARD); |
| 1767 | } |
| 1768 | else |
| 1769 | { |
| 1770 | // If this symbol is not fully resolved, we need to add a |
| 1771 | // GOT entry with a dynamic relocation. |
| 1772 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1773 | if (gsym->is_from_dynobj() |
| 1774 | || gsym->is_undefined() |
| 1775 | || gsym->is_preemptible() |
| 1776 | || (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 1777 | && parameters->options().output_is_position_independent())) |
| 1778 | got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, |
| 1779 | rel_dyn, elfcpp::R_386_GLOB_DAT); |
| 1780 | else |
| 1781 | { |
| 1782 | // For a STT_GNU_IFUNC symbol we want to write the PLT |
| 1783 | // offset into the GOT, so that function pointer |
| 1784 | // comparisons work correctly. |
| 1785 | bool is_new; |
| 1786 | if (gsym->type() != elfcpp::STT_GNU_IFUNC) |
| 1787 | is_new = got->add_global(gsym, GOT_TYPE_STANDARD); |
| 1788 | else |
| 1789 | { |
| 1790 | is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); |
| 1791 | // Tell the dynamic linker to use the PLT address |
| 1792 | // when resolving relocations. |
| 1793 | if (gsym->is_from_dynobj() |
| 1794 | && !parameters->options().shared()) |
| 1795 | gsym->set_needs_dynsym_value(); |
| 1796 | } |
| 1797 | if (is_new) |
| 1798 | { |
| 1799 | unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); |
| 1800 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 1801 | got, got_off); |
| 1802 | } |
| 1803 | } |
| 1804 | } |
| 1805 | } |
| 1806 | break; |
| 1807 | |
| 1808 | case elfcpp::R_386_PLT32: |
| 1809 | // If the symbol is fully resolved, this is just a PC32 reloc. |
| 1810 | // Otherwise we need a PLT entry. |
| 1811 | if (gsym->final_value_is_known()) |
| 1812 | break; |
| 1813 | // If building a shared library, we can also skip the PLT entry |
| 1814 | // if the symbol is defined in the output file and is protected |
| 1815 | // or hidden. |
| 1816 | if (gsym->is_defined() |
| 1817 | && !gsym->is_from_dynobj() |
| 1818 | && !gsym->is_preemptible()) |
| 1819 | break; |
| 1820 | target->make_plt_entry(symtab, layout, gsym); |
| 1821 | break; |
| 1822 | |
| 1823 | case elfcpp::R_386_GOTOFF: |
| 1824 | case elfcpp::R_386_GOTPC: |
| 1825 | // We need a GOT section. |
| 1826 | target->got_section(symtab, layout); |
| 1827 | break; |
| 1828 | |
| 1829 | // These are relocations which should only be seen by the |
| 1830 | // dynamic linker, and should never be seen here. |
| 1831 | case elfcpp::R_386_COPY: |
| 1832 | case elfcpp::R_386_GLOB_DAT: |
| 1833 | case elfcpp::R_386_JUMP_SLOT: |
| 1834 | case elfcpp::R_386_RELATIVE: |
| 1835 | case elfcpp::R_386_IRELATIVE: |
| 1836 | case elfcpp::R_386_TLS_TPOFF: |
| 1837 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1838 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1839 | case elfcpp::R_386_TLS_TPOFF32: |
| 1840 | case elfcpp::R_386_TLS_DESC: |
| 1841 | gold_error(_("%s: unexpected reloc %u in object file"), |
| 1842 | object->name().c_str(), r_type); |
| 1843 | break; |
| 1844 | |
| 1845 | // These are initial tls relocs, which are expected when |
| 1846 | // linking. |
| 1847 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1848 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 1849 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1850 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1851 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1852 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1853 | case elfcpp::R_386_TLS_IE_32: |
| 1854 | case elfcpp::R_386_TLS_GOTIE: |
| 1855 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1856 | case elfcpp::R_386_TLS_LE_32: |
| 1857 | { |
| 1858 | const bool is_final = gsym->final_value_is_known(); |
| 1859 | const tls::Tls_optimization optimized_type |
| 1860 | = Target_i386::optimize_tls_reloc(is_final, r_type); |
| 1861 | switch (r_type) |
| 1862 | { |
| 1863 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1864 | if (optimized_type == tls::TLSOPT_NONE) |
| 1865 | { |
| 1866 | // Create a pair of GOT entries for the module index and |
| 1867 | // dtv-relative offset. |
| 1868 | Output_data_got<32, false>* got |
| 1869 | = target->got_section(symtab, layout); |
| 1870 | got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, |
| 1871 | target->rel_dyn_section(layout), |
| 1872 | elfcpp::R_386_TLS_DTPMOD32, |
| 1873 | elfcpp::R_386_TLS_DTPOFF32); |
| 1874 | } |
| 1875 | else if (optimized_type == tls::TLSOPT_TO_IE) |
| 1876 | { |
| 1877 | // Create a GOT entry for the tp-relative offset. |
| 1878 | Output_data_got<32, false>* got |
| 1879 | = target->got_section(symtab, layout); |
| 1880 | got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| 1881 | target->rel_dyn_section(layout), |
| 1882 | elfcpp::R_386_TLS_TPOFF); |
| 1883 | } |
| 1884 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1885 | unsupported_reloc_global(object, r_type, gsym); |
| 1886 | break; |
| 1887 | |
| 1888 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url) |
| 1889 | target->define_tls_base_symbol(symtab, layout); |
| 1890 | if (optimized_type == tls::TLSOPT_NONE) |
| 1891 | { |
| 1892 | // Create a double GOT entry with an R_386_TLS_DESC |
| 1893 | // reloc. The R_386_TLS_DESC reloc is resolved |
| 1894 | // lazily, so the GOT entry needs to be in an area in |
| 1895 | // .got.plt, not .got. Call got_section to make sure |
| 1896 | // the section has been created. |
| 1897 | target->got_section(symtab, layout); |
| 1898 | Output_data_got<32, false>* got = target->got_tlsdesc_section(); |
| 1899 | Reloc_section* rt = target->rel_tls_desc_section(layout); |
| 1900 | got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, |
| 1901 | elfcpp::R_386_TLS_DESC, 0); |
| 1902 | } |
| 1903 | else if (optimized_type == tls::TLSOPT_TO_IE) |
| 1904 | { |
| 1905 | // Create a GOT entry for the tp-relative offset. |
| 1906 | Output_data_got<32, false>* got |
| 1907 | = target->got_section(symtab, layout); |
| 1908 | got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| 1909 | target->rel_dyn_section(layout), |
| 1910 | elfcpp::R_386_TLS_TPOFF); |
| 1911 | } |
| 1912 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1913 | unsupported_reloc_global(object, r_type, gsym); |
| 1914 | break; |
| 1915 | |
| 1916 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1917 | break; |
| 1918 | |
| 1919 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1920 | if (optimized_type == tls::TLSOPT_NONE) |
| 1921 | { |
| 1922 | // Create a GOT entry for the module index. |
| 1923 | target->got_mod_index_entry(symtab, layout, object); |
| 1924 | } |
| 1925 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1926 | unsupported_reloc_global(object, r_type, gsym); |
| 1927 | break; |
| 1928 | |
| 1929 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1930 | break; |
| 1931 | |
| 1932 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1933 | case elfcpp::R_386_TLS_IE_32: |
| 1934 | case elfcpp::R_386_TLS_GOTIE: |
| 1935 | layout->set_has_static_tls(); |
| 1936 | if (optimized_type == tls::TLSOPT_NONE) |
| 1937 | { |
| 1938 | // For the R_386_TLS_IE relocation, we need to create a |
| 1939 | // dynamic relocation when building a shared library. |
| 1940 | if (r_type == elfcpp::R_386_TLS_IE |
| 1941 | && parameters->options().shared()) |
| 1942 | { |
| 1943 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1944 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 1945 | output_section, object, |
| 1946 | data_shndx, |
| 1947 | reloc.get_r_offset()); |
| 1948 | } |
| 1949 | // Create a GOT entry for the tp-relative offset. |
| 1950 | Output_data_got<32, false>* got |
| 1951 | = target->got_section(symtab, layout); |
| 1952 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1953 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1954 | : elfcpp::R_386_TLS_TPOFF); |
| 1955 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1956 | ? GOT_TYPE_TLS_OFFSET |
| 1957 | : GOT_TYPE_TLS_NOFFSET); |
| 1958 | got->add_global_with_rel(gsym, got_type, |
| 1959 | target->rel_dyn_section(layout), |
| 1960 | dyn_r_type); |
| 1961 | } |
| 1962 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1963 | unsupported_reloc_global(object, r_type, gsym); |
| 1964 | break; |
| 1965 | |
| 1966 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1967 | case elfcpp::R_386_TLS_LE_32: |
| 1968 | layout->set_has_static_tls(); |
| 1969 | if (parameters->options().shared()) |
| 1970 | { |
| 1971 | // We need to create a dynamic relocation. |
| 1972 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| 1973 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1974 | : elfcpp::R_386_TLS_TPOFF); |
| 1975 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1976 | rel_dyn->add_global(gsym, dyn_r_type, output_section, object, |
| 1977 | data_shndx, reloc.get_r_offset()); |
| 1978 | } |
| 1979 | break; |
| 1980 | |
| 1981 | default: |
| 1982 | gold_unreachable(); |
| 1983 | } |
| 1984 | } |
| 1985 | break; |
| 1986 | |
| 1987 | case elfcpp::R_386_32PLT: |
| 1988 | case elfcpp::R_386_TLS_GD_32: |
| 1989 | case elfcpp::R_386_TLS_GD_PUSH: |
| 1990 | case elfcpp::R_386_TLS_GD_CALL: |
| 1991 | case elfcpp::R_386_TLS_GD_POP: |
| 1992 | case elfcpp::R_386_TLS_LDM_32: |
| 1993 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 1994 | case elfcpp::R_386_TLS_LDM_CALL: |
| 1995 | case elfcpp::R_386_TLS_LDM_POP: |
| 1996 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 1997 | default: |
| 1998 | unsupported_reloc_global(object, r_type, gsym); |
| 1999 | break; |
| 2000 | } |
| 2001 | } |
| 2002 | |
| 2003 | // Process relocations for gc. |
| 2004 | |
| 2005 | void |
| 2006 | Target_i386::gc_process_relocs(Symbol_table* symtab, |
| 2007 | Layout* layout, |
| 2008 | Sized_relobj<32, false>* object, |
| 2009 | unsigned int data_shndx, |
| 2010 | unsigned int, |
| 2011 | const unsigned char* prelocs, |
| 2012 | size_t reloc_count, |
| 2013 | Output_section* output_section, |
| 2014 | bool needs_special_offset_handling, |
| 2015 | size_t local_symbol_count, |
| 2016 | const unsigned char* plocal_symbols) |
| 2017 | { |
| 2018 | gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| 2019 | Target_i386::Scan, |
| 2020 | Target_i386::Relocatable_size_for_reloc>( |
| 2021 | symtab, |
| 2022 | layout, |
| 2023 | this, |
| 2024 | object, |
| 2025 | data_shndx, |
| 2026 | prelocs, |
| 2027 | reloc_count, |
| 2028 | output_section, |
| 2029 | needs_special_offset_handling, |
| 2030 | local_symbol_count, |
| 2031 | plocal_symbols); |
| 2032 | } |
| 2033 | |
| 2034 | // Scan relocations for a section. |
| 2035 | |
| 2036 | void |
| 2037 | Target_i386::scan_relocs(Symbol_table* symtab, |
| 2038 | Layout* layout, |
| 2039 | Sized_relobj<32, false>* object, |
| 2040 | unsigned int data_shndx, |
| 2041 | unsigned int sh_type, |
| 2042 | const unsigned char* prelocs, |
| 2043 | size_t reloc_count, |
| 2044 | Output_section* output_section, |
| 2045 | bool needs_special_offset_handling, |
| 2046 | size_t local_symbol_count, |
| 2047 | const unsigned char* plocal_symbols) |
| 2048 | { |
| 2049 | if (sh_type == elfcpp::SHT_RELA) |
| 2050 | { |
| 2051 | gold_error(_("%s: unsupported RELA reloc section"), |
| 2052 | object->name().c_str()); |
| 2053 | return; |
| 2054 | } |
| 2055 | |
| 2056 | gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| 2057 | Target_i386::Scan>( |
| 2058 | symtab, |
| 2059 | layout, |
| 2060 | this, |
| 2061 | object, |
| 2062 | data_shndx, |
| 2063 | prelocs, |
| 2064 | reloc_count, |
| 2065 | output_section, |
| 2066 | needs_special_offset_handling, |
| 2067 | local_symbol_count, |
| 2068 | plocal_symbols); |
| 2069 | } |
| 2070 | |
| 2071 | // Finalize the sections. |
| 2072 | |
| 2073 | void |
| 2074 | Target_i386::do_finalize_sections( |
| 2075 | Layout* layout, |
| 2076 | const Input_objects*, |
| 2077 | Symbol_table* symtab) |
| 2078 | { |
| 2079 | const Reloc_section* rel_plt = (this->plt_ == NULL |
| 2080 | ? NULL |
| 2081 | : this->plt_->rel_plt()); |
| 2082 | layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt, |
| 2083 | this->rel_dyn_, true, false); |
| 2084 | |
| 2085 | // Emit any relocs we saved in an attempt to avoid generating COPY |
| 2086 | // relocs. |
| 2087 | if (this->copy_relocs_.any_saved_relocs()) |
| 2088 | this->copy_relocs_.emit(this->rel_dyn_section(layout)); |
| 2089 | |
| 2090 | // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of |
| 2091 | // the .got.plt section. |
| 2092 | Symbol* sym = this->global_offset_table_; |
| 2093 | if (sym != NULL) |
| 2094 | { |
| 2095 | uint32_t data_size = this->got_plt_->current_data_size(); |
| 2096 | symtab->get_sized_symbol<32>(sym)->set_symsize(data_size); |
| 2097 | } |
| 2098 | } |
| 2099 | |
| 2100 | // Return whether a direct absolute static relocation needs to be applied. |
| 2101 | // In cases where Scan::local() or Scan::global() has created |
| 2102 | // a dynamic relocation other than R_386_RELATIVE, the addend |
| 2103 | // of the relocation is carried in the data, and we must not |
| 2104 | // apply the static relocation. |
| 2105 | |
| 2106 | inline bool |
| 2107 | Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| 2108 | int ref_flags, |
| 2109 | bool is_32bit, |
| 2110 | Output_section* output_section) |
| 2111 | { |
| 2112 | // If the output section is not allocated, then we didn't call |
| 2113 | // scan_relocs, we didn't create a dynamic reloc, and we must apply |
| 2114 | // the reloc here. |
| 2115 | if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0) |
| 2116 | return true; |
| 2117 | |
| 2118 | // For local symbols, we will have created a non-RELATIVE dynamic |
| 2119 | // relocation only if (a) the output is position independent, |
| 2120 | // (b) the relocation is absolute (not pc- or segment-relative), and |
| 2121 | // (c) the relocation is not 32 bits wide. |
| 2122 | if (gsym == NULL) |
| 2123 | return !(parameters->options().output_is_position_independent() |
| 2124 | && (ref_flags & Symbol::ABSOLUTE_REF) |
| 2125 | && !is_32bit); |
| 2126 | |
| 2127 | // For global symbols, we use the same helper routines used in the |
| 2128 | // scan pass. If we did not create a dynamic relocation, or if we |
| 2129 | // created a RELATIVE dynamic relocation, we should apply the static |
| 2130 | // relocation. |
| 2131 | bool has_dyn = gsym->needs_dynamic_reloc(ref_flags); |
| 2132 | bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF) |
| 2133 | && gsym->can_use_relative_reloc(ref_flags |
| 2134 | & Symbol::FUNCTION_CALL); |
| 2135 | return !has_dyn || is_rel; |
| 2136 | } |
| 2137 | |
| 2138 | // Perform a relocation. |
| 2139 | |
| 2140 | inline bool |
| 2141 | Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, |
| 2142 | Target_i386* target, |
| 2143 | Output_section* output_section, |
| 2144 | size_t relnum, |
| 2145 | const elfcpp::Rel<32, false>& rel, |
| 2146 | unsigned int r_type, |
| 2147 | const Sized_symbol<32>* gsym, |
| 2148 | const Symbol_value<32>* psymval, |
| 2149 | unsigned char* view, |
| 2150 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 2151 | section_size_type view_size) |
| 2152 | { |
| 2153 | if (this->skip_call_tls_get_addr_) |
| 2154 | { |
| 2155 | if ((r_type != elfcpp::R_386_PLT32 |
| 2156 | && r_type != elfcpp::R_386_PC32) |
| 2157 | || gsym == NULL |
| 2158 | || strcmp(gsym->name(), "___tls_get_addr") != 0) |
| 2159 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2160 | _("missing expected TLS relocation")); |
| 2161 | else |
| 2162 | { |
| 2163 | this->skip_call_tls_get_addr_ = false; |
| 2164 | return false; |
| 2165 | } |
| 2166 | } |
| 2167 | |
| 2168 | const Sized_relobj<32, false>* object = relinfo->object; |
| 2169 | |
| 2170 | // Pick the value to use for symbols defined in shared objects. |
| 2171 | Symbol_value<32> symval; |
| 2172 | if (gsym != NULL |
| 2173 | && gsym->type() == elfcpp::STT_GNU_IFUNC |
| 2174 | && r_type == elfcpp::R_386_32 |
| 2175 | && gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF) |
| 2176 | && gsym->can_use_relative_reloc(false) |
| 2177 | && !gsym->is_from_dynobj() |
| 2178 | && !gsym->is_undefined() |
| 2179 | && !gsym->is_preemptible()) |
| 2180 | { |
| 2181 | // In this case we are generating a R_386_IRELATIVE reloc. We |
| 2182 | // want to use the real value of the symbol, not the PLT offset. |
| 2183 | } |
| 2184 | else if (gsym != NULL |
| 2185 | && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8 |
| 2186 | || r_type == elfcpp::R_386_PC16 |
| 2187 | || r_type == elfcpp::R_386_PC32)) |
| 2188 | { |
| 2189 | symval.set_output_value(target->plt_section()->address() |
| 2190 | + gsym->plt_offset()); |
| 2191 | psymval = &symval; |
| 2192 | } |
| 2193 | else if (gsym == NULL && psymval->is_ifunc_symbol()) |
| 2194 | { |
| 2195 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2196 | if (object->local_has_plt_offset(r_sym)) |
| 2197 | { |
| 2198 | symval.set_output_value(target->plt_section()->address() |
| 2199 | + object->local_plt_offset(r_sym)); |
| 2200 | psymval = &symval; |
| 2201 | } |
| 2202 | } |
| 2203 | |
| 2204 | // Get the GOT offset if needed. |
| 2205 | // The GOT pointer points to the end of the GOT section. |
| 2206 | // We need to subtract the size of the GOT section to get |
| 2207 | // the actual offset to use in the relocation. |
| 2208 | bool have_got_offset = false; |
| 2209 | unsigned int got_offset = 0; |
| 2210 | switch (r_type) |
| 2211 | { |
| 2212 | case elfcpp::R_386_GOT32: |
| 2213 | if (gsym != NULL) |
| 2214 | { |
| 2215 | gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); |
| 2216 | got_offset = (gsym->got_offset(GOT_TYPE_STANDARD) |
| 2217 | - target->got_size()); |
| 2218 | } |
| 2219 | else |
| 2220 | { |
| 2221 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2222 | gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); |
| 2223 | got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) |
| 2224 | - target->got_size()); |
| 2225 | } |
| 2226 | have_got_offset = true; |
| 2227 | break; |
| 2228 | |
| 2229 | default: |
| 2230 | break; |
| 2231 | } |
| 2232 | |
| 2233 | switch (r_type) |
| 2234 | { |
| 2235 | case elfcpp::R_386_NONE: |
| 2236 | case elfcpp::R_386_GNU_VTINHERIT: |
| 2237 | case elfcpp::R_386_GNU_VTENTRY: |
| 2238 | break; |
| 2239 | |
| 2240 | case elfcpp::R_386_32: |
| 2241 | if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, |
| 2242 | output_section)) |
| 2243 | Relocate_functions<32, false>::rel32(view, object, psymval); |
| 2244 | break; |
| 2245 | |
| 2246 | case elfcpp::R_386_PC32: |
| 2247 | { |
| 2248 | int ref_flags = Symbol::NON_PIC_REF; |
| 2249 | if (gsym != NULL && gsym->is_func()) |
| 2250 | ref_flags |= Symbol::FUNCTION_CALL; |
| 2251 | if (should_apply_static_reloc(gsym, ref_flags, true, output_section)) |
| 2252 | Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| 2253 | } |
| 2254 | break; |
| 2255 | |
| 2256 | case elfcpp::R_386_16: |
| 2257 | if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, |
| 2258 | output_section)) |
| 2259 | Relocate_functions<32, false>::rel16(view, object, psymval); |
| 2260 | break; |
| 2261 | |
| 2262 | case elfcpp::R_386_PC16: |
| 2263 | { |
| 2264 | int ref_flags = Symbol::NON_PIC_REF; |
| 2265 | if (gsym != NULL && gsym->is_func()) |
| 2266 | ref_flags |= Symbol::FUNCTION_CALL; |
| 2267 | if (should_apply_static_reloc(gsym, ref_flags, false, output_section)) |
| 2268 | Relocate_functions<32, false>::pcrel16(view, object, psymval, address); |
| 2269 | } |
| 2270 | break; |
| 2271 | |
| 2272 | case elfcpp::R_386_8: |
| 2273 | if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, |
| 2274 | output_section)) |
| 2275 | Relocate_functions<32, false>::rel8(view, object, psymval); |
| 2276 | break; |
| 2277 | |
| 2278 | case elfcpp::R_386_PC8: |
| 2279 | { |
| 2280 | int ref_flags = Symbol::NON_PIC_REF; |
| 2281 | if (gsym != NULL && gsym->is_func()) |
| 2282 | ref_flags |= Symbol::FUNCTION_CALL; |
| 2283 | if (should_apply_static_reloc(gsym, ref_flags, false, |
| 2284 | output_section)) |
| 2285 | Relocate_functions<32, false>::pcrel8(view, object, psymval, address); |
| 2286 | } |
| 2287 | break; |
| 2288 | |
| 2289 | case elfcpp::R_386_PLT32: |
| 2290 | gold_assert(gsym == NULL |
| 2291 | || gsym->has_plt_offset() |
| 2292 | || gsym->final_value_is_known() |
| 2293 | || (gsym->is_defined() |
| 2294 | && !gsym->is_from_dynobj() |
| 2295 | && !gsym->is_preemptible())); |
| 2296 | Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| 2297 | break; |
| 2298 | |
| 2299 | case elfcpp::R_386_GOT32: |
| 2300 | gold_assert(have_got_offset); |
| 2301 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2302 | break; |
| 2303 | |
| 2304 | case elfcpp::R_386_GOTOFF: |
| 2305 | { |
| 2306 | elfcpp::Elf_types<32>::Elf_Addr value; |
| 2307 | value = (psymval->value(object, 0) |
| 2308 | - target->got_plt_section()->address()); |
| 2309 | Relocate_functions<32, false>::rel32(view, value); |
| 2310 | } |
| 2311 | break; |
| 2312 | |
| 2313 | case elfcpp::R_386_GOTPC: |
| 2314 | { |
| 2315 | elfcpp::Elf_types<32>::Elf_Addr value; |
| 2316 | value = target->got_plt_section()->address(); |
| 2317 | Relocate_functions<32, false>::pcrel32(view, value, address); |
| 2318 | } |
| 2319 | break; |
| 2320 | |
| 2321 | case elfcpp::R_386_COPY: |
| 2322 | case elfcpp::R_386_GLOB_DAT: |
| 2323 | case elfcpp::R_386_JUMP_SLOT: |
| 2324 | case elfcpp::R_386_RELATIVE: |
| 2325 | case elfcpp::R_386_IRELATIVE: |
| 2326 | // These are outstanding tls relocs, which are unexpected when |
| 2327 | // linking. |
| 2328 | case elfcpp::R_386_TLS_TPOFF: |
| 2329 | case elfcpp::R_386_TLS_DTPMOD32: |
| 2330 | case elfcpp::R_386_TLS_DTPOFF32: |
| 2331 | case elfcpp::R_386_TLS_TPOFF32: |
| 2332 | case elfcpp::R_386_TLS_DESC: |
| 2333 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2334 | _("unexpected reloc %u in object file"), |
| 2335 | r_type); |
| 2336 | break; |
| 2337 | |
| 2338 | // These are initial tls relocs, which are expected when |
| 2339 | // linking. |
| 2340 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2341 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 2342 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2343 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2344 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 2345 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 2346 | case elfcpp::R_386_TLS_IE_32: |
| 2347 | case elfcpp::R_386_TLS_GOTIE: |
| 2348 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 2349 | case elfcpp::R_386_TLS_LE_32: |
| 2350 | this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval, |
| 2351 | view, address, view_size); |
| 2352 | break; |
| 2353 | |
| 2354 | case elfcpp::R_386_32PLT: |
| 2355 | case elfcpp::R_386_TLS_GD_32: |
| 2356 | case elfcpp::R_386_TLS_GD_PUSH: |
| 2357 | case elfcpp::R_386_TLS_GD_CALL: |
| 2358 | case elfcpp::R_386_TLS_GD_POP: |
| 2359 | case elfcpp::R_386_TLS_LDM_32: |
| 2360 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 2361 | case elfcpp::R_386_TLS_LDM_CALL: |
| 2362 | case elfcpp::R_386_TLS_LDM_POP: |
| 2363 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 2364 | default: |
| 2365 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2366 | _("unsupported reloc %u"), |
| 2367 | r_type); |
| 2368 | break; |
| 2369 | } |
| 2370 | |
| 2371 | return true; |
| 2372 | } |
| 2373 | |
| 2374 | // Perform a TLS relocation. |
| 2375 | |
| 2376 | inline void |
| 2377 | Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo, |
| 2378 | Target_i386* target, |
| 2379 | size_t relnum, |
| 2380 | const elfcpp::Rel<32, false>& rel, |
| 2381 | unsigned int r_type, |
| 2382 | const Sized_symbol<32>* gsym, |
| 2383 | const Symbol_value<32>* psymval, |
| 2384 | unsigned char* view, |
| 2385 | elfcpp::Elf_types<32>::Elf_Addr, |
| 2386 | section_size_type view_size) |
| 2387 | { |
| 2388 | Output_segment* tls_segment = relinfo->layout->tls_segment(); |
| 2389 | |
| 2390 | const Sized_relobj<32, false>* object = relinfo->object; |
| 2391 | |
| 2392 | elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0); |
| 2393 | |
| 2394 | const bool is_final = (gsym == NULL |
| 2395 | ? !parameters->options().shared() |
| 2396 | : gsym->final_value_is_known()); |
| 2397 | const tls::Tls_optimization optimized_type |
| 2398 | = Target_i386::optimize_tls_reloc(is_final, r_type); |
| 2399 | switch (r_type) |
| 2400 | { |
| 2401 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2402 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2403 | { |
| 2404 | gold_assert(tls_segment != NULL); |
| 2405 | this->tls_gd_to_le(relinfo, relnum, tls_segment, |
| 2406 | rel, r_type, value, view, |
| 2407 | view_size); |
| 2408 | break; |
| 2409 | } |
| 2410 | else |
| 2411 | { |
| 2412 | unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE |
| 2413 | ? GOT_TYPE_TLS_NOFFSET |
| 2414 | : GOT_TYPE_TLS_PAIR); |
| 2415 | unsigned int got_offset; |
| 2416 | if (gsym != NULL) |
| 2417 | { |
| 2418 | gold_assert(gsym->has_got_offset(got_type)); |
| 2419 | got_offset = gsym->got_offset(got_type) - target->got_size(); |
| 2420 | } |
| 2421 | else |
| 2422 | { |
| 2423 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2424 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 2425 | got_offset = (object->local_got_offset(r_sym, got_type) |
| 2426 | - target->got_size()); |
| 2427 | } |
| 2428 | if (optimized_type == tls::TLSOPT_TO_IE) |
| 2429 | { |
| 2430 | gold_assert(tls_segment != NULL); |
| 2431 | this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, |
| 2432 | got_offset, view, view_size); |
| 2433 | break; |
| 2434 | } |
| 2435 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2436 | { |
| 2437 | // Relocate the field with the offset of the pair of GOT |
| 2438 | // entries. |
| 2439 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2440 | break; |
| 2441 | } |
| 2442 | } |
| 2443 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2444 | _("unsupported reloc %u"), |
| 2445 | r_type); |
| 2446 | break; |
| 2447 | |
| 2448 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 2449 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2450 | this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; |
| 2451 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2452 | { |
| 2453 | gold_assert(tls_segment != NULL); |
| 2454 | this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, |
| 2455 | rel, r_type, value, view, |
| 2456 | view_size); |
| 2457 | break; |
| 2458 | } |
| 2459 | else |
| 2460 | { |
| 2461 | unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE |
| 2462 | ? GOT_TYPE_TLS_NOFFSET |
| 2463 | : GOT_TYPE_TLS_DESC); |
| 2464 | unsigned int got_offset = 0; |
| 2465 | if (r_type == elfcpp::R_386_TLS_GOTDESC |
| 2466 | && optimized_type == tls::TLSOPT_NONE) |
| 2467 | { |
| 2468 | // We created GOT entries in the .got.tlsdesc portion of |
| 2469 | // the .got.plt section, but the offset stored in the |
| 2470 | // symbol is the offset within .got.tlsdesc. |
| 2471 | got_offset = (target->got_size() |
| 2472 | + target->got_plt_section()->data_size()); |
| 2473 | } |
| 2474 | if (gsym != NULL) |
| 2475 | { |
| 2476 | gold_assert(gsym->has_got_offset(got_type)); |
| 2477 | got_offset += gsym->got_offset(got_type) - target->got_size(); |
| 2478 | } |
| 2479 | else |
| 2480 | { |
| 2481 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2482 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 2483 | got_offset += (object->local_got_offset(r_sym, got_type) |
| 2484 | - target->got_size()); |
| 2485 | } |
| 2486 | if (optimized_type == tls::TLSOPT_TO_IE) |
| 2487 | { |
| 2488 | gold_assert(tls_segment != NULL); |
| 2489 | this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, |
| 2490 | got_offset, view, view_size); |
| 2491 | break; |
| 2492 | } |
| 2493 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2494 | { |
| 2495 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 2496 | { |
| 2497 | // Relocate the field with the offset of the pair of GOT |
| 2498 | // entries. |
| 2499 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2500 | } |
| 2501 | break; |
| 2502 | } |
| 2503 | } |
| 2504 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2505 | _("unsupported reloc %u"), |
| 2506 | r_type); |
| 2507 | break; |
| 2508 | |
| 2509 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2510 | if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN) |
| 2511 | { |
| 2512 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2513 | _("both SUN and GNU model " |
| 2514 | "TLS relocations")); |
| 2515 | break; |
| 2516 | } |
| 2517 | this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; |
| 2518 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2519 | { |
| 2520 | gold_assert(tls_segment != NULL); |
| 2521 | this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type, |
| 2522 | value, view, view_size); |
| 2523 | break; |
| 2524 | } |
| 2525 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2526 | { |
| 2527 | // Relocate the field with the offset of the GOT entry for |
| 2528 | // the module index. |
| 2529 | unsigned int got_offset; |
| 2530 | got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) |
| 2531 | - target->got_size()); |
| 2532 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2533 | break; |
| 2534 | } |
| 2535 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2536 | _("unsupported reloc %u"), |
| 2537 | r_type); |
| 2538 | break; |
| 2539 | |
| 2540 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 2541 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2542 | { |
| 2543 | // This reloc can appear in debugging sections, in which |
| 2544 | // case we must not convert to local-exec. We decide what |
| 2545 | // to do based on whether the section is marked as |
| 2546 | // containing executable code. That is what the GNU linker |
| 2547 | // does as well. |
| 2548 | elfcpp::Shdr<32, false> shdr(relinfo->data_shdr); |
| 2549 | if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0) |
| 2550 | { |
| 2551 | gold_assert(tls_segment != NULL); |
| 2552 | value -= tls_segment->memsz(); |
| 2553 | } |
| 2554 | } |
| 2555 | Relocate_functions<32, false>::rel32(view, value); |
| 2556 | break; |
| 2557 | |
| 2558 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 2559 | case elfcpp::R_386_TLS_GOTIE: |
| 2560 | case elfcpp::R_386_TLS_IE_32: |
| 2561 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2562 | { |
| 2563 | gold_assert(tls_segment != NULL); |
| 2564 | Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, |
| 2565 | rel, r_type, value, view, |
| 2566 | view_size); |
| 2567 | break; |
| 2568 | } |
| 2569 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2570 | { |
| 2571 | // Relocate the field with the offset of the GOT entry for |
| 2572 | // the tp-relative offset of the symbol. |
| 2573 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 2574 | ? GOT_TYPE_TLS_OFFSET |
| 2575 | : GOT_TYPE_TLS_NOFFSET); |
| 2576 | unsigned int got_offset; |
| 2577 | if (gsym != NULL) |
| 2578 | { |
| 2579 | gold_assert(gsym->has_got_offset(got_type)); |
| 2580 | got_offset = gsym->got_offset(got_type); |
| 2581 | } |
| 2582 | else |
| 2583 | { |
| 2584 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2585 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 2586 | got_offset = object->local_got_offset(r_sym, got_type); |
| 2587 | } |
| 2588 | // For the R_386_TLS_IE relocation, we need to apply the |
| 2589 | // absolute address of the GOT entry. |
| 2590 | if (r_type == elfcpp::R_386_TLS_IE) |
| 2591 | got_offset += target->got_plt_section()->address(); |
| 2592 | // All GOT offsets are relative to the end of the GOT. |
| 2593 | got_offset -= target->got_size(); |
| 2594 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2595 | break; |
| 2596 | } |
| 2597 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2598 | _("unsupported reloc %u"), |
| 2599 | r_type); |
| 2600 | break; |
| 2601 | |
| 2602 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 2603 | // If we're creating a shared library, a dynamic relocation will |
| 2604 | // have been created for this location, so do not apply it now. |
| 2605 | if (!parameters->options().shared()) |
| 2606 | { |
| 2607 | gold_assert(tls_segment != NULL); |
| 2608 | value -= tls_segment->memsz(); |
| 2609 | Relocate_functions<32, false>::rel32(view, value); |
| 2610 | } |
| 2611 | break; |
| 2612 | |
| 2613 | case elfcpp::R_386_TLS_LE_32: |
| 2614 | // If we're creating a shared library, a dynamic relocation will |
| 2615 | // have been created for this location, so do not apply it now. |
| 2616 | if (!parameters->options().shared()) |
| 2617 | { |
| 2618 | gold_assert(tls_segment != NULL); |
| 2619 | value = tls_segment->memsz() - value; |
| 2620 | Relocate_functions<32, false>::rel32(view, value); |
| 2621 | } |
| 2622 | break; |
| 2623 | } |
| 2624 | } |
| 2625 | |
| 2626 | // Do a relocation in which we convert a TLS General-Dynamic to a |
| 2627 | // Local-Exec. |
| 2628 | |
| 2629 | inline void |
| 2630 | Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo, |
| 2631 | size_t relnum, |
| 2632 | Output_segment* tls_segment, |
| 2633 | const elfcpp::Rel<32, false>& rel, |
| 2634 | unsigned int, |
| 2635 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 2636 | unsigned char* view, |
| 2637 | section_size_type view_size) |
| 2638 | { |
| 2639 | // leal foo(,%reg,1),%eax; call ___tls_get_addr |
| 2640 | // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| 2641 | // leal foo(%reg),%eax; call ___tls_get_addr |
| 2642 | // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| 2643 | |
| 2644 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2645 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 2646 | |
| 2647 | unsigned char op1 = view[-1]; |
| 2648 | unsigned char op2 = view[-2]; |
| 2649 | |
| 2650 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2651 | op2 == 0x8d || op2 == 0x04); |
| 2652 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 2653 | |
| 2654 | int roff = 5; |
| 2655 | |
| 2656 | if (op2 == 0x04) |
| 2657 | { |
| 2658 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| 2659 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| 2660 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2661 | ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| 2662 | memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 2663 | } |
| 2664 | else |
| 2665 | { |
| 2666 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2667 | (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| 2668 | if (rel.get_r_offset() + 9 < view_size |
| 2669 | && view[9] == 0x90) |
| 2670 | { |
| 2671 | // There is a trailing nop. Use the size byte subl. |
| 2672 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 2673 | roff = 6; |
| 2674 | } |
| 2675 | else |
| 2676 | { |
| 2677 | // Use the five byte subl. |
| 2678 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| 2679 | } |
| 2680 | } |
| 2681 | |
| 2682 | value = tls_segment->memsz() - value; |
| 2683 | Relocate_functions<32, false>::rel32(view + roff, value); |
| 2684 | |
| 2685 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 2686 | // We can skip it. |
| 2687 | this->skip_call_tls_get_addr_ = true; |
| 2688 | } |
| 2689 | |
| 2690 | // Do a relocation in which we convert a TLS General-Dynamic to an |
| 2691 | // Initial-Exec. |
| 2692 | |
| 2693 | inline void |
| 2694 | Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo, |
| 2695 | size_t relnum, |
| 2696 | Output_segment*, |
| 2697 | const elfcpp::Rel<32, false>& rel, |
| 2698 | unsigned int, |
| 2699 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 2700 | unsigned char* view, |
| 2701 | section_size_type view_size) |
| 2702 | { |
| 2703 | // leal foo(,%ebx,1),%eax; call ___tls_get_addr |
| 2704 | // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax |
| 2705 | |
| 2706 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2707 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 2708 | |
| 2709 | unsigned char op1 = view[-1]; |
| 2710 | unsigned char op2 = view[-2]; |
| 2711 | |
| 2712 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2713 | op2 == 0x8d || op2 == 0x04); |
| 2714 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 2715 | |
| 2716 | int roff = 5; |
| 2717 | |
| 2718 | // FIXME: For now, support only the first (SIB) form. |
| 2719 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04); |
| 2720 | |
| 2721 | if (op2 == 0x04) |
| 2722 | { |
| 2723 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| 2724 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| 2725 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2726 | ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| 2727 | memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12); |
| 2728 | } |
| 2729 | else |
| 2730 | { |
| 2731 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2732 | (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| 2733 | if (rel.get_r_offset() + 9 < view_size |
| 2734 | && view[9] == 0x90) |
| 2735 | { |
| 2736 | // FIXME: This is not the right instruction sequence. |
| 2737 | // There is a trailing nop. Use the size byte subl. |
| 2738 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 2739 | roff = 6; |
| 2740 | } |
| 2741 | else |
| 2742 | { |
| 2743 | // FIXME: This is not the right instruction sequence. |
| 2744 | // Use the five byte subl. |
| 2745 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| 2746 | } |
| 2747 | } |
| 2748 | |
| 2749 | Relocate_functions<32, false>::rel32(view + roff, value); |
| 2750 | |
| 2751 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 2752 | // We can skip it. |
| 2753 | this->skip_call_tls_get_addr_ = true; |
| 2754 | } |
| 2755 | |
| 2756 | // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL |
| 2757 | // General-Dynamic to a Local-Exec. |
| 2758 | |
| 2759 | inline void |
| 2760 | Target_i386::Relocate::tls_desc_gd_to_le( |
| 2761 | const Relocate_info<32, false>* relinfo, |
| 2762 | size_t relnum, |
| 2763 | Output_segment* tls_segment, |
| 2764 | const elfcpp::Rel<32, false>& rel, |
| 2765 | unsigned int r_type, |
| 2766 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 2767 | unsigned char* view, |
| 2768 | section_size_type view_size) |
| 2769 | { |
| 2770 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 2771 | { |
| 2772 | // leal foo@TLSDESC(%ebx), %eax |
| 2773 | // ==> leal foo@NTPOFF, %eax |
| 2774 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2775 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 2776 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2777 | view[-2] == 0x8d && view[-1] == 0x83); |
| 2778 | view[-1] = 0x05; |
| 2779 | value -= tls_segment->memsz(); |
| 2780 | Relocate_functions<32, false>::rel32(view, value); |
| 2781 | } |
| 2782 | else |
| 2783 | { |
| 2784 | // call *foo@TLSCALL(%eax) |
| 2785 | // ==> nop; nop |
| 2786 | gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); |
| 2787 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); |
| 2788 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2789 | view[0] == 0xff && view[1] == 0x10); |
| 2790 | view[0] = 0x66; |
| 2791 | view[1] = 0x90; |
| 2792 | } |
| 2793 | } |
| 2794 | |
| 2795 | // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL |
| 2796 | // General-Dynamic to an Initial-Exec. |
| 2797 | |
| 2798 | inline void |
| 2799 | Target_i386::Relocate::tls_desc_gd_to_ie( |
| 2800 | const Relocate_info<32, false>* relinfo, |
| 2801 | size_t relnum, |
| 2802 | Output_segment*, |
| 2803 | const elfcpp::Rel<32, false>& rel, |
| 2804 | unsigned int r_type, |
| 2805 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 2806 | unsigned char* view, |
| 2807 | section_size_type view_size) |
| 2808 | { |
| 2809 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 2810 | { |
| 2811 | // leal foo@TLSDESC(%ebx), %eax |
| 2812 | // ==> movl foo@GOTNTPOFF(%ebx), %eax |
| 2813 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2814 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 2815 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2816 | view[-2] == 0x8d && view[-1] == 0x83); |
| 2817 | view[-2] = 0x8b; |
| 2818 | Relocate_functions<32, false>::rel32(view, value); |
| 2819 | } |
| 2820 | else |
| 2821 | { |
| 2822 | // call *foo@TLSCALL(%eax) |
| 2823 | // ==> nop; nop |
| 2824 | gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); |
| 2825 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); |
| 2826 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2827 | view[0] == 0xff && view[1] == 0x10); |
| 2828 | view[0] = 0x66; |
| 2829 | view[1] = 0x90; |
| 2830 | } |
| 2831 | } |
| 2832 | |
| 2833 | // Do a relocation in which we convert a TLS Local-Dynamic to a |
| 2834 | // Local-Exec. |
| 2835 | |
| 2836 | inline void |
| 2837 | Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo, |
| 2838 | size_t relnum, |
| 2839 | Output_segment*, |
| 2840 | const elfcpp::Rel<32, false>& rel, |
| 2841 | unsigned int, |
| 2842 | elfcpp::Elf_types<32>::Elf_Addr, |
| 2843 | unsigned char* view, |
| 2844 | section_size_type view_size) |
| 2845 | { |
| 2846 | // leal foo(%reg), %eax; call ___tls_get_addr |
| 2847 | // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi |
| 2848 | |
| 2849 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2850 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 2851 | |
| 2852 | // FIXME: Does this test really always pass? |
| 2853 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2854 | view[-2] == 0x8d && view[-1] == 0x83); |
| 2855 | |
| 2856 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 2857 | |
| 2858 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11); |
| 2859 | |
| 2860 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 2861 | // We can skip it. |
| 2862 | this->skip_call_tls_get_addr_ = true; |
| 2863 | } |
| 2864 | |
| 2865 | // Do a relocation in which we convert a TLS Initial-Exec to a |
| 2866 | // Local-Exec. |
| 2867 | |
| 2868 | inline void |
| 2869 | Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo, |
| 2870 | size_t relnum, |
| 2871 | Output_segment* tls_segment, |
| 2872 | const elfcpp::Rel<32, false>& rel, |
| 2873 | unsigned int r_type, |
| 2874 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 2875 | unsigned char* view, |
| 2876 | section_size_type view_size) |
| 2877 | { |
| 2878 | // We have to actually change the instructions, which means that we |
| 2879 | // need to examine the opcodes to figure out which instruction we |
| 2880 | // are looking at. |
| 2881 | if (r_type == elfcpp::R_386_TLS_IE) |
| 2882 | { |
| 2883 | // movl %gs:XX,%eax ==> movl $YY,%eax |
| 2884 | // movl %gs:XX,%reg ==> movl $YY,%reg |
| 2885 | // addl %gs:XX,%reg ==> addl $YY,%reg |
| 2886 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1); |
| 2887 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 2888 | |
| 2889 | unsigned char op1 = view[-1]; |
| 2890 | if (op1 == 0xa1) |
| 2891 | { |
| 2892 | // movl XX,%eax ==> movl $YY,%eax |
| 2893 | view[-1] = 0xb8; |
| 2894 | } |
| 2895 | else |
| 2896 | { |
| 2897 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2898 | |
| 2899 | unsigned char op2 = view[-2]; |
| 2900 | if (op2 == 0x8b) |
| 2901 | { |
| 2902 | // movl XX,%reg ==> movl $YY,%reg |
| 2903 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2904 | (op1 & 0xc7) == 0x05); |
| 2905 | view[-2] = 0xc7; |
| 2906 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 2907 | } |
| 2908 | else if (op2 == 0x03) |
| 2909 | { |
| 2910 | // addl XX,%reg ==> addl $YY,%reg |
| 2911 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2912 | (op1 & 0xc7) == 0x05); |
| 2913 | view[-2] = 0x81; |
| 2914 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 2915 | } |
| 2916 | else |
| 2917 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| 2918 | } |
| 2919 | } |
| 2920 | else |
| 2921 | { |
| 2922 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 2923 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 2924 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 2925 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 2926 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 2927 | |
| 2928 | unsigned char op1 = view[-1]; |
| 2929 | unsigned char op2 = view[-2]; |
| 2930 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 2931 | (op1 & 0xc0) == 0x80 && (op1 & 7) != 4); |
| 2932 | if (op2 == 0x8b) |
| 2933 | { |
| 2934 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 2935 | view[-2] = 0xc7; |
| 2936 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 2937 | } |
| 2938 | else if (op2 == 0x2b) |
| 2939 | { |
| 2940 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 2941 | view[-2] = 0x81; |
| 2942 | view[-1] = 0xe8 | ((op1 >> 3) & 7); |
| 2943 | } |
| 2944 | else if (op2 == 0x03) |
| 2945 | { |
| 2946 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 2947 | view[-2] = 0x81; |
| 2948 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 2949 | } |
| 2950 | else |
| 2951 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| 2952 | } |
| 2953 | |
| 2954 | value = tls_segment->memsz() - value; |
| 2955 | if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE) |
| 2956 | value = - value; |
| 2957 | |
| 2958 | Relocate_functions<32, false>::rel32(view, value); |
| 2959 | } |
| 2960 | |
| 2961 | // Relocate section data. |
| 2962 | |
| 2963 | void |
| 2964 | Target_i386::relocate_section(const Relocate_info<32, false>* relinfo, |
| 2965 | unsigned int sh_type, |
| 2966 | const unsigned char* prelocs, |
| 2967 | size_t reloc_count, |
| 2968 | Output_section* output_section, |
| 2969 | bool needs_special_offset_handling, |
| 2970 | unsigned char* view, |
| 2971 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 2972 | section_size_type view_size, |
| 2973 | const Reloc_symbol_changes* reloc_symbol_changes) |
| 2974 | { |
| 2975 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 2976 | |
| 2977 | gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL, |
| 2978 | Target_i386::Relocate>( |
| 2979 | relinfo, |
| 2980 | this, |
| 2981 | prelocs, |
| 2982 | reloc_count, |
| 2983 | output_section, |
| 2984 | needs_special_offset_handling, |
| 2985 | view, |
| 2986 | address, |
| 2987 | view_size, |
| 2988 | reloc_symbol_changes); |
| 2989 | } |
| 2990 | |
| 2991 | // Return the size of a relocation while scanning during a relocatable |
| 2992 | // link. |
| 2993 | |
| 2994 | unsigned int |
| 2995 | Target_i386::Relocatable_size_for_reloc::get_size_for_reloc( |
| 2996 | unsigned int r_type, |
| 2997 | Relobj* object) |
| 2998 | { |
| 2999 | switch (r_type) |
| 3000 | { |
| 3001 | case elfcpp::R_386_NONE: |
| 3002 | case elfcpp::R_386_GNU_VTINHERIT: |
| 3003 | case elfcpp::R_386_GNU_VTENTRY: |
| 3004 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 3005 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 3006 | case elfcpp::R_386_TLS_DESC_CALL: |
| 3007 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 3008 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 3009 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 3010 | case elfcpp::R_386_TLS_IE_32: |
| 3011 | case elfcpp::R_386_TLS_GOTIE: |
| 3012 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 3013 | case elfcpp::R_386_TLS_LE_32: |
| 3014 | return 0; |
| 3015 | |
| 3016 | case elfcpp::R_386_32: |
| 3017 | case elfcpp::R_386_PC32: |
| 3018 | case elfcpp::R_386_GOT32: |
| 3019 | case elfcpp::R_386_PLT32: |
| 3020 | case elfcpp::R_386_GOTOFF: |
| 3021 | case elfcpp::R_386_GOTPC: |
| 3022 | return 4; |
| 3023 | |
| 3024 | case elfcpp::R_386_16: |
| 3025 | case elfcpp::R_386_PC16: |
| 3026 | return 2; |
| 3027 | |
| 3028 | case elfcpp::R_386_8: |
| 3029 | case elfcpp::R_386_PC8: |
| 3030 | return 1; |
| 3031 | |
| 3032 | // These are relocations which should only be seen by the |
| 3033 | // dynamic linker, and should never be seen here. |
| 3034 | case elfcpp::R_386_COPY: |
| 3035 | case elfcpp::R_386_GLOB_DAT: |
| 3036 | case elfcpp::R_386_JUMP_SLOT: |
| 3037 | case elfcpp::R_386_RELATIVE: |
| 3038 | case elfcpp::R_386_IRELATIVE: |
| 3039 | case elfcpp::R_386_TLS_TPOFF: |
| 3040 | case elfcpp::R_386_TLS_DTPMOD32: |
| 3041 | case elfcpp::R_386_TLS_DTPOFF32: |
| 3042 | case elfcpp::R_386_TLS_TPOFF32: |
| 3043 | case elfcpp::R_386_TLS_DESC: |
| 3044 | object->error(_("unexpected reloc %u in object file"), r_type); |
| 3045 | return 0; |
| 3046 | |
| 3047 | case elfcpp::R_386_32PLT: |
| 3048 | case elfcpp::R_386_TLS_GD_32: |
| 3049 | case elfcpp::R_386_TLS_GD_PUSH: |
| 3050 | case elfcpp::R_386_TLS_GD_CALL: |
| 3051 | case elfcpp::R_386_TLS_GD_POP: |
| 3052 | case elfcpp::R_386_TLS_LDM_32: |
| 3053 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 3054 | case elfcpp::R_386_TLS_LDM_CALL: |
| 3055 | case elfcpp::R_386_TLS_LDM_POP: |
| 3056 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 3057 | default: |
| 3058 | object->error(_("unsupported reloc %u in object file"), r_type); |
| 3059 | return 0; |
| 3060 | } |
| 3061 | } |
| 3062 | |
| 3063 | // Scan the relocs during a relocatable link. |
| 3064 | |
| 3065 | void |
| 3066 | Target_i386::scan_relocatable_relocs(Symbol_table* symtab, |
| 3067 | Layout* layout, |
| 3068 | Sized_relobj<32, false>* object, |
| 3069 | unsigned int data_shndx, |
| 3070 | unsigned int sh_type, |
| 3071 | const unsigned char* prelocs, |
| 3072 | size_t reloc_count, |
| 3073 | Output_section* output_section, |
| 3074 | bool needs_special_offset_handling, |
| 3075 | size_t local_symbol_count, |
| 3076 | const unsigned char* plocal_symbols, |
| 3077 | Relocatable_relocs* rr) |
| 3078 | { |
| 3079 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 3080 | |
| 3081 | typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, |
| 3082 | Relocatable_size_for_reloc> Scan_relocatable_relocs; |
| 3083 | |
| 3084 | gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL, |
| 3085 | Scan_relocatable_relocs>( |
| 3086 | symtab, |
| 3087 | layout, |
| 3088 | object, |
| 3089 | data_shndx, |
| 3090 | prelocs, |
| 3091 | reloc_count, |
| 3092 | output_section, |
| 3093 | needs_special_offset_handling, |
| 3094 | local_symbol_count, |
| 3095 | plocal_symbols, |
| 3096 | rr); |
| 3097 | } |
| 3098 | |
| 3099 | // Relocate a section during a relocatable link. |
| 3100 | |
| 3101 | void |
| 3102 | Target_i386::relocate_for_relocatable( |
| 3103 | const Relocate_info<32, false>* relinfo, |
| 3104 | unsigned int sh_type, |
| 3105 | const unsigned char* prelocs, |
| 3106 | size_t reloc_count, |
| 3107 | Output_section* output_section, |
| 3108 | off_t offset_in_output_section, |
| 3109 | const Relocatable_relocs* rr, |
| 3110 | unsigned char* view, |
| 3111 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 3112 | section_size_type view_size, |
| 3113 | unsigned char* reloc_view, |
| 3114 | section_size_type reloc_view_size) |
| 3115 | { |
| 3116 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 3117 | |
| 3118 | gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>( |
| 3119 | relinfo, |
| 3120 | prelocs, |
| 3121 | reloc_count, |
| 3122 | output_section, |
| 3123 | offset_in_output_section, |
| 3124 | rr, |
| 3125 | view, |
| 3126 | view_address, |
| 3127 | view_size, |
| 3128 | reloc_view, |
| 3129 | reloc_view_size); |
| 3130 | } |
| 3131 | |
| 3132 | // Return the value to use for a dynamic which requires special |
| 3133 | // treatment. This is how we support equality comparisons of function |
| 3134 | // pointers across shared library boundaries, as described in the |
| 3135 | // processor specific ABI supplement. |
| 3136 | |
| 3137 | uint64_t |
| 3138 | Target_i386::do_dynsym_value(const Symbol* gsym) const |
| 3139 | { |
| 3140 | gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); |
| 3141 | return this->plt_section()->address() + gsym->plt_offset(); |
| 3142 | } |
| 3143 | |
| 3144 | // Return a string used to fill a code section with nops to take up |
| 3145 | // the specified length. |
| 3146 | |
| 3147 | std::string |
| 3148 | Target_i386::do_code_fill(section_size_type length) const |
| 3149 | { |
| 3150 | if (length >= 16) |
| 3151 | { |
| 3152 | // Build a jmp instruction to skip over the bytes. |
| 3153 | unsigned char jmp[5]; |
| 3154 | jmp[0] = 0xe9; |
| 3155 | elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); |
| 3156 | return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) |
| 3157 | + std::string(length - 5, '\0')); |
| 3158 | } |
| 3159 | |
| 3160 | // Nop sequences of various lengths. |
| 3161 | const char nop1[1] = { 0x90 }; // nop |
| 3162 | const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax |
| 3163 | const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi |
| 3164 | const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi |
| 3165 | const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop |
| 3166 | 0x00 }; // leal 0(%esi,1),%esi |
| 3167 | const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 3168 | 0x00, 0x00 }; |
| 3169 | const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi |
| 3170 | 0x00, 0x00, 0x00 }; |
| 3171 | const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop |
| 3172 | 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi |
| 3173 | const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi |
| 3174 | 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi |
| 3175 | 0x00 }; |
| 3176 | const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi |
| 3177 | 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi |
| 3178 | 0x00, 0x00 }; |
| 3179 | const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi |
| 3180 | 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi |
| 3181 | 0x00, 0x00, 0x00 }; |
| 3182 | const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 3183 | 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi |
| 3184 | 0x00, 0x00, 0x00, 0x00 }; |
| 3185 | const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 3186 | 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi |
| 3187 | 0x27, 0x00, 0x00, 0x00, |
| 3188 | 0x00 }; |
| 3189 | const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi |
| 3190 | 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi |
| 3191 | 0xbc, 0x27, 0x00, 0x00, |
| 3192 | 0x00, 0x00 }; |
| 3193 | const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15 |
| 3194 | 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,... |
| 3195 | 0x90, 0x90, 0x90, 0x90, |
| 3196 | 0x90, 0x90, 0x90 }; |
| 3197 | |
| 3198 | const char* nops[16] = { |
| 3199 | NULL, |
| 3200 | nop1, nop2, nop3, nop4, nop5, nop6, nop7, |
| 3201 | nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 |
| 3202 | }; |
| 3203 | |
| 3204 | return std::string(nops[length], length); |
| 3205 | } |
| 3206 | |
| 3207 | // Return whether SYM should be treated as a call to a non-split |
| 3208 | // function. We don't want that to be true of a call to a |
| 3209 | // get_pc_thunk function. |
| 3210 | |
| 3211 | bool |
| 3212 | Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const |
| 3213 | { |
| 3214 | return (sym->type() == elfcpp::STT_FUNC |
| 3215 | && !is_prefix_of("__i686.get_pc_thunk.", sym->name())); |
| 3216 | } |
| 3217 | |
| 3218 | // FNOFFSET in section SHNDX in OBJECT is the start of a function |
| 3219 | // compiled with -fstack-split. The function calls non-stack-split |
| 3220 | // code. We have to change the function so that it always ensures |
| 3221 | // that it has enough stack space to run some random function. |
| 3222 | |
| 3223 | void |
| 3224 | Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx, |
| 3225 | section_offset_type fnoffset, |
| 3226 | section_size_type fnsize, |
| 3227 | unsigned char* view, |
| 3228 | section_size_type view_size, |
| 3229 | std::string* from, |
| 3230 | std::string* to) const |
| 3231 | { |
| 3232 | // The function starts with a comparison of the stack pointer and a |
| 3233 | // field in the TCB. This is followed by a jump. |
| 3234 | |
| 3235 | // cmp %gs:NN,%esp |
| 3236 | if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3) |
| 3237 | && fnsize > 7) |
| 3238 | { |
| 3239 | // We will call __morestack if the carry flag is set after this |
| 3240 | // comparison. We turn the comparison into an stc instruction |
| 3241 | // and some nops. |
| 3242 | view[fnoffset] = '\xf9'; |
| 3243 | this->set_view_to_nop(view, view_size, fnoffset + 1, 6); |
| 3244 | } |
| 3245 | // lea NN(%esp),%ecx |
| 3246 | // lea NN(%esp),%edx |
| 3247 | else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3) |
| 3248 | || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3)) |
| 3249 | && fnsize > 7) |
| 3250 | { |
| 3251 | // This is loading an offset from the stack pointer for a |
| 3252 | // comparison. The offset is negative, so we decrease the |
| 3253 | // offset by the amount of space we need for the stack. This |
| 3254 | // means we will avoid calling __morestack if there happens to |
| 3255 | // be plenty of space on the stack already. |
| 3256 | unsigned char* pval = view + fnoffset + 3; |
| 3257 | uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); |
| 3258 | val -= parameters->options().split_stack_adjust_size(); |
| 3259 | elfcpp::Swap_unaligned<32, false>::writeval(pval, val); |
| 3260 | } |
| 3261 | else |
| 3262 | { |
| 3263 | if (!object->has_no_split_stack()) |
| 3264 | object->error(_("failed to match split-stack sequence at " |
| 3265 | "section %u offset %0zx"), |
| 3266 | shndx, static_cast<size_t>(fnoffset)); |
| 3267 | return; |
| 3268 | } |
| 3269 | |
| 3270 | // We have to change the function so that it calls |
| 3271 | // __morestack_non_split instead of __morestack. The former will |
| 3272 | // allocate additional stack space. |
| 3273 | *from = "__morestack"; |
| 3274 | *to = "__morestack_non_split"; |
| 3275 | } |
| 3276 | |
| 3277 | // The selector for i386 object files. |
| 3278 | |
| 3279 | class Target_selector_i386 : public Target_selector_freebsd |
| 3280 | { |
| 3281 | public: |
| 3282 | Target_selector_i386() |
| 3283 | : Target_selector_freebsd(elfcpp::EM_386, 32, false, |
| 3284 | "elf32-i386", "elf32-i386-freebsd") |
| 3285 | { } |
| 3286 | |
| 3287 | Target* |
| 3288 | do_instantiate_target() |
| 3289 | { return new Target_i386(); } |
| 3290 | }; |
| 3291 | |
| 3292 | Target_selector_i386 target_selector_i386; |
| 3293 | |
| 3294 | } // End anonymous namespace. |