1 // target-reloc.h -- target specific relocation support -*- C++ -*- 2 3 // Copyright (C) 2006-2014 Free Software Foundation, Inc. 4 // Written by Ian Lance Taylor <iant (at) google.com>. 5 6 // This file is part of gold. 7 8 // This program is free software; you can redistribute it and/or modify 9 // it under the terms of the GNU General Public License as published by 10 // the Free Software Foundation; either version 3 of the License, or 11 // (at your option) any later version. 12 13 // This program is distributed in the hope that it will be useful, 14 // but WITHOUT ANY WARRANTY; without even the implied warranty of 15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 // GNU General Public License for more details. 17 18 // You should have received a copy of the GNU General Public License 19 // along with this program; if not, write to the Free Software 20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 21 // MA 02110-1301, USA. 22 23 #ifndef GOLD_TARGET_RELOC_H 24 #define GOLD_TARGET_RELOC_H 25 26 #include "elfcpp.h" 27 #include "symtab.h" 28 #include "object.h" 29 #include "reloc.h" 30 #include "reloc-types.h" 31 32 namespace gold 33 { 34 35 // This function implements the generic part of reloc scanning. The 36 // template parameter Scan must be a class type which provides two 37 // functions: local() and global(). Those functions implement the 38 // machine specific part of scanning. We do it this way to 39 // avoid making a function call for each relocation, and to avoid 40 // repeating the generic code for each target. 41 42 template<int size, bool big_endian, typename Target_type, int sh_type, 43 typename Scan> 44 inline void 45 scan_relocs( 46 Symbol_table* symtab, 47 Layout* layout, 48 Target_type* target, 49 Sized_relobj_file<size, big_endian>* object, 50 unsigned int data_shndx, 51 const unsigned char* prelocs, 52 size_t reloc_count, 53 Output_section* output_section, 54 bool needs_special_offset_handling, 55 size_t local_count, 56 const unsigned char* plocal_syms) 57 { 58 typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; 59 const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; 60 const int sym_size = elfcpp::Elf_sizes<size>::sym_size; 61 Scan scan; 62 63 for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) 64 { 65 Reltype reloc(prelocs); 66 67 if (needs_special_offset_handling 68 && !output_section->is_input_address_mapped(object, data_shndx, 69 reloc.get_r_offset())) 70 continue; 71 72 typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); 73 unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); 74 unsigned int r_type = elfcpp::elf_r_type<size>(r_info); 75 76 if (r_sym < local_count) 77 { 78 gold_assert(plocal_syms != NULL); 79 typename elfcpp::Sym<size, big_endian> lsym(plocal_syms 80 + r_sym * sym_size); 81 unsigned int shndx = lsym.get_st_shndx(); 82 bool is_ordinary; 83 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); 84 // If RELOC is a relocation against a local symbol in a 85 // section we are discarding then we can ignore it. It will 86 // eventually become a reloc against the value zero. 87 // 88 // FIXME: We should issue a warning if this is an 89 // allocated section; is this the best place to do it? 90 // 91 // FIXME: The old GNU linker would in some cases look 92 // for the linkonce section which caused this section to 93 // be discarded, and, if the other section was the same 94 // size, change the reloc to refer to the other section. 95 // That seems risky and weird to me, and I don't know of 96 // any case where it is actually required. 97 bool is_discarded = (is_ordinary 98 && shndx != elfcpp::SHN_UNDEF 99 && !object->is_section_included(shndx) 100 && !symtab->is_section_folded(object, shndx)); 101 scan.local(symtab, layout, target, object, data_shndx, 102 output_section, reloc, r_type, lsym, is_discarded); 103 } 104 else 105 { 106 Symbol* gsym = object->global_symbol(r_sym); 107 gold_assert(gsym != NULL); 108 if (gsym->is_forwarder()) 109 gsym = symtab->resolve_forwards(gsym); 110 111 scan.global(symtab, layout, target, object, data_shndx, 112 output_section, reloc, r_type, gsym); 113 } 114 } 115 } 116 117 // Behavior for relocations to discarded comdat sections. 118 119 enum Comdat_behavior 120 { 121 CB_UNDETERMINED, // Not yet determined -- need to look at section name. 122 CB_PRETEND, // Attempt to map to the corresponding kept section. 123 CB_IGNORE, // Ignore the relocation. 124 CB_WARNING // Print a warning. 125 }; 126 127 class Default_comdat_behavior 128 { 129 public: 130 // Decide what the linker should do for relocations that refer to 131 // discarded comdat sections. This decision is based on the name of 132 // the section being relocated. 133 134 inline Comdat_behavior 135 get(const char* name) 136 { 137 if (Layout::is_debug_info_section(name)) 138 return CB_PRETEND; 139 if (strcmp(name, ".eh_frame") == 0 140 || strcmp(name, ".gcc_except_table") == 0) 141 return CB_IGNORE; 142 return CB_WARNING; 143 } 144 }; 145 146 // Give an error for a symbol with non-default visibility which is not 147 // defined locally. 148 149 inline void 150 visibility_error(const Symbol* sym) 151 { 152 const char* v; 153 switch (sym->visibility()) 154 { 155 case elfcpp::STV_INTERNAL: 156 v = _("internal"); 157 break; 158 case elfcpp::STV_HIDDEN: 159 v = _("hidden"); 160 break; 161 case elfcpp::STV_PROTECTED: 162 v = _("protected"); 163 break; 164 default: 165 gold_unreachable(); 166 } 167 gold_error(_("%s symbol '%s' is not defined locally"), 168 v, sym->name()); 169 } 170 171 // Return true if we are should issue an error saying that SYM is an 172 // undefined symbol. This is called if there is a relocation against 173 // SYM. 174 175 inline bool 176 issue_undefined_symbol_error(const Symbol* sym) 177 { 178 // We only report global symbols. 179 if (sym == NULL) 180 return false; 181 182 // We only report undefined symbols. 183 if (!sym->is_undefined() && !sym->is_placeholder()) 184 return false; 185 186 // We don't report weak symbols. 187 if (sym->is_weak_undefined()) 188 return false; 189 190 // We don't report symbols defined in discarded sections. 191 if (sym->is_defined_in_discarded_section()) 192 return false; 193 194 // If the target defines this symbol, don't report it here. 195 if (parameters->target().is_defined_by_abi(sym)) 196 return false; 197 198 // See if we've been told to ignore whether this symbol is 199 // undefined. 200 const char* const u = parameters->options().unresolved_symbols(); 201 if (u != NULL) 202 { 203 if (strcmp(u, "ignore-all") == 0) 204 return false; 205 if (strcmp(u, "report-all") == 0) 206 return true; 207 if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn()) 208 return false; 209 if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg()) 210 return false; 211 } 212 213 // If the symbol is hidden, report it. 214 if (sym->visibility() == elfcpp::STV_HIDDEN) 215 return true; 216 217 // When creating a shared library, only report unresolved symbols if 218 // -z defs was used. 219 if (parameters->options().shared() && !parameters->options().defs()) 220 return false; 221 222 // Otherwise issue a warning. 223 return true; 224 } 225 226 // This function implements the generic part of relocation processing. 227 // The template parameter Relocate must be a class type which provides 228 // a single function, relocate(), which implements the machine 229 // specific part of a relocation. 230 231 // The template parameter Relocate_comdat_behavior is a class type 232 // which provides a single function, get(), which determines what the 233 // linker should do for relocations that refer to discarded comdat 234 // sections. 235 236 // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of 237 // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA. 238 // RELOCATE implements operator() to do a relocation. 239 240 // PRELOCS points to the relocation data. RELOC_COUNT is the number 241 // of relocs. OUTPUT_SECTION is the output section. 242 // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be 243 // mapped to output offsets. 244 245 // VIEW is the section data, VIEW_ADDRESS is its memory address, and 246 // VIEW_SIZE is the size. These refer to the input section, unless 247 // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to 248 // the output section. 249 250 // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is 251 // not NULL, it is a vector indexed by relocation index. If that 252 // entry is not NULL, it points to a global symbol which used as the 253 // symbol for the relocation, ignoring the symbol index in the 254 // relocation. 255 256 template<int size, bool big_endian, typename Target_type, int sh_type, 257 typename Relocate, 258 typename Relocate_comdat_behavior> 259 inline void 260 relocate_section( 261 const Relocate_info<size, big_endian>* relinfo, 262 Target_type* target, 263 const unsigned char* prelocs, 264 size_t reloc_count, 265 Output_section* output_section, 266 bool needs_special_offset_handling, 267 unsigned char* view, 268 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 269 section_size_type view_size, 270 const Reloc_symbol_changes* reloc_symbol_changes) 271 { 272 typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; 273 const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; 274 Relocate relocate; 275 Relocate_comdat_behavior relocate_comdat_behavior; 276 277 Sized_relobj_file<size, big_endian>* object = relinfo->object; 278 unsigned int local_count = object->local_symbol_count(); 279 280 Comdat_behavior comdat_behavior = CB_UNDETERMINED; 281 282 for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) 283 { 284 Reltype reloc(prelocs); 285 286 section_offset_type offset = 287 convert_to_section_size_type(reloc.get_r_offset()); 288 289 if (needs_special_offset_handling) 290 { 291 offset = output_section->output_offset(relinfo->object, 292 relinfo->data_shndx, 293 offset); 294 if (offset == -1) 295 continue; 296 } 297 298 typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); 299 unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); 300 unsigned int r_type = elfcpp::elf_r_type<size>(r_info); 301 302 const Sized_symbol<size>* sym; 303 304 Symbol_value<size> symval; 305 const Symbol_value<size> *psymval; 306 bool is_defined_in_discarded_section; 307 unsigned int shndx; 308 if (r_sym < local_count 309 && (reloc_symbol_changes == NULL 310 || (*reloc_symbol_changes)[i] == NULL)) 311 { 312 sym = NULL; 313 psymval = object->local_symbol(r_sym); 314 315 // If the local symbol belongs to a section we are discarding, 316 // and that section is a debug section, try to find the 317 // corresponding kept section and map this symbol to its 318 // counterpart in the kept section. The symbol must not 319 // correspond to a section we are folding. 320 bool is_ordinary; 321 shndx = psymval->input_shndx(&is_ordinary); 322 is_defined_in_discarded_section = 323 (is_ordinary 324 && shndx != elfcpp::SHN_UNDEF 325 && !object->is_section_included(shndx) 326 && !relinfo->symtab->is_section_folded(object, shndx)); 327 } 328 else 329 { 330 const Symbol* gsym; 331 if (reloc_symbol_changes != NULL 332 && (*reloc_symbol_changes)[i] != NULL) 333 gsym = (*reloc_symbol_changes)[i]; 334 else 335 { 336 gsym = object->global_symbol(r_sym); 337 gold_assert(gsym != NULL); 338 if (gsym->is_forwarder()) 339 gsym = relinfo->symtab->resolve_forwards(gsym); 340 } 341 342 sym = static_cast<const Sized_symbol<size>*>(gsym); 343 if (sym->has_symtab_index() && sym->symtab_index() != -1U) 344 symval.set_output_symtab_index(sym->symtab_index()); 345 else 346 symval.set_no_output_symtab_entry(); 347 symval.set_output_value(sym->value()); 348 if (gsym->type() == elfcpp::STT_TLS) 349 symval.set_is_tls_symbol(); 350 else if (gsym->type() == elfcpp::STT_GNU_IFUNC) 351 symval.set_is_ifunc_symbol(); 352 psymval = &symval; 353 354 is_defined_in_discarded_section = 355 (gsym->is_defined_in_discarded_section() 356 && gsym->is_undefined()); 357 shndx = 0; 358 } 359 360 Symbol_value<size> symval2; 361 if (is_defined_in_discarded_section) 362 { 363 if (comdat_behavior == CB_UNDETERMINED) 364 { 365 std::string name = object->section_name(relinfo->data_shndx); 366 comdat_behavior = relocate_comdat_behavior.get(name.c_str()); 367 } 368 if (comdat_behavior == CB_PRETEND) 369 { 370 // FIXME: This case does not work for global symbols. 371 // We have no place to store the original section index. 372 // Fortunately this does not matter for comdat sections, 373 // only for sections explicitly discarded by a linker 374 // script. 375 bool found; 376 typename elfcpp::Elf_types<size>::Elf_Addr value = 377 object->map_to_kept_section(shndx, &found); 378 if (found) 379 symval2.set_output_value(value + psymval->input_value()); 380 else 381 symval2.set_output_value(0); 382 } 383 else 384 { 385 if (comdat_behavior == CB_WARNING) 386 gold_warning_at_location(relinfo, i, offset, 387 _("relocation refers to discarded " 388 "section")); 389 symval2.set_output_value(0); 390 } 391 symval2.set_no_output_symtab_entry(); 392 psymval = &symval2; 393 } 394 395 // If OFFSET is out of range, still let the target decide to 396 // ignore the relocation. Pass in NULL as the VIEW argument so 397 // that it can return quickly without trashing an invalid memory 398 // address. 399 unsigned char *v = view + offset; 400 if (offset < 0 || static_cast<section_size_type>(offset) >= view_size) 401 v = NULL; 402 403 if (!relocate.relocate(relinfo, target, output_section, i, reloc, 404 r_type, sym, psymval, v, view_address + offset, 405 view_size)) 406 continue; 407 408 if (v == NULL) 409 { 410 gold_error_at_location(relinfo, i, offset, 411 _("reloc has bad offset %zu"), 412 static_cast<size_t>(offset)); 413 continue; 414 } 415 416 if (issue_undefined_symbol_error(sym)) 417 gold_undefined_symbol_at_location(sym, relinfo, i, offset); 418 else if (sym != NULL 419 && sym->visibility() != elfcpp::STV_DEFAULT 420 && (sym->is_strong_undefined() || sym->is_from_dynobj())) 421 visibility_error(sym); 422 423 if (sym != NULL && sym->has_warning()) 424 relinfo->symtab->issue_warning(sym, relinfo, i, offset); 425 } 426 } 427 428 // Apply an incremental relocation. 429 430 template<int size, bool big_endian, typename Target_type, 431 typename Relocate> 432 void 433 apply_relocation(const Relocate_info<size, big_endian>* relinfo, 434 Target_type* target, 435 typename elfcpp::Elf_types<size>::Elf_Addr r_offset, 436 unsigned int r_type, 437 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, 438 const Symbol* gsym, 439 unsigned char* view, 440 typename elfcpp::Elf_types<size>::Elf_Addr address, 441 section_size_type view_size) 442 { 443 // Construct the ELF relocation in a temporary buffer. 444 const int reloc_size = elfcpp::Elf_sizes<size>::rela_size; 445 unsigned char relbuf[reloc_size]; 446 elfcpp::Rela<size, big_endian> rel(relbuf); 447 elfcpp::Rela_write<size, big_endian> orel(relbuf); 448 orel.put_r_offset(r_offset); 449 orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type)); 450 orel.put_r_addend(r_addend); 451 452 // Setup a Symbol_value for the global symbol. 453 const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym); 454 Symbol_value<size> symval; 455 gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U); 456 symval.set_output_symtab_index(sym->symtab_index()); 457 symval.set_output_value(sym->value()); 458 if (gsym->type() == elfcpp::STT_TLS) 459 symval.set_is_tls_symbol(); 460 else if (gsym->type() == elfcpp::STT_GNU_IFUNC) 461 symval.set_is_ifunc_symbol(); 462 463 Relocate relocate; 464 relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval, 465 view + r_offset, address + r_offset, view_size); 466 } 467 468 // This class may be used as a typical class for the 469 // Scan_relocatable_reloc parameter to scan_relocatable_relocs. The 470 // template parameter Classify_reloc must be a class type which 471 // provides a function get_size_for_reloc which returns the number of 472 // bytes to which a reloc applies. This class is intended to capture 473 // the most typical target behaviour, while still permitting targets 474 // to define their own independent class for Scan_relocatable_reloc. 475 476 template<int sh_type, typename Classify_reloc> 477 class Default_scan_relocatable_relocs 478 { 479 public: 480 // Return the strategy to use for a local symbol which is not a 481 // section symbol, given the relocation type. 482 inline Relocatable_relocs::Reloc_strategy 483 local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym) 484 { 485 // We assume that relocation type 0 is NONE. Targets which are 486 // different must override. 487 if (r_type == 0 && r_sym == 0) 488 return Relocatable_relocs::RELOC_DISCARD; 489 return Relocatable_relocs::RELOC_COPY; 490 } 491 492 // Return the strategy to use for a local symbol which is a section 493 // symbol, given the relocation type. 494 inline Relocatable_relocs::Reloc_strategy 495 local_section_strategy(unsigned int r_type, Relobj* object) 496 { 497 if (sh_type == elfcpp::SHT_RELA) 498 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; 499 else 500 { 501 Classify_reloc classify; 502 switch (classify.get_size_for_reloc(r_type, object)) 503 { 504 case 0: 505 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; 506 case 1: 507 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1; 508 case 2: 509 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2; 510 case 4: 511 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4; 512 case 8: 513 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8; 514 default: 515 gold_unreachable(); 516 } 517 } 518 } 519 520 // Return the strategy to use for a global symbol, given the 521 // relocation type, the object, and the symbol index. 522 inline Relocatable_relocs::Reloc_strategy 523 global_strategy(unsigned int, Relobj*, unsigned int) 524 { return Relocatable_relocs::RELOC_COPY; } 525 }; 526 527 // Scan relocs during a relocatable link. This is a default 528 // definition which should work for most targets. 529 // Scan_relocatable_reloc must name a class type which provides three 530 // functions which return a Relocatable_relocs::Reloc_strategy code: 531 // global_strategy, local_non_section_strategy, and 532 // local_section_strategy. Most targets should be able to use 533 // Default_scan_relocatable_relocs as this class. 534 535 template<int size, bool big_endian, int sh_type, 536 typename Scan_relocatable_reloc> 537 void 538 scan_relocatable_relocs( 539 Symbol_table*, 540 Layout*, 541 Sized_relobj_file<size, big_endian>* object, 542 unsigned int data_shndx, 543 const unsigned char* prelocs, 544 size_t reloc_count, 545 Output_section* output_section, 546 bool needs_special_offset_handling, 547 size_t local_symbol_count, 548 const unsigned char* plocal_syms, 549 Relocatable_relocs* rr) 550 { 551 typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; 552 const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; 553 const int sym_size = elfcpp::Elf_sizes<size>::sym_size; 554 Scan_relocatable_reloc scan; 555 556 for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) 557 { 558 Reltype reloc(prelocs); 559 560 Relocatable_relocs::Reloc_strategy strategy; 561 562 if (needs_special_offset_handling 563 && !output_section->is_input_address_mapped(object, data_shndx, 564 reloc.get_r_offset())) 565 strategy = Relocatable_relocs::RELOC_DISCARD; 566 else 567 { 568 typename elfcpp::Elf_types<size>::Elf_WXword r_info = 569 reloc.get_r_info(); 570 const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); 571 const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); 572 573 if (r_sym >= local_symbol_count) 574 strategy = scan.global_strategy(r_type, object, r_sym); 575 else 576 { 577 gold_assert(plocal_syms != NULL); 578 typename elfcpp::Sym<size, big_endian> lsym(plocal_syms 579 + r_sym * sym_size); 580 unsigned int shndx = lsym.get_st_shndx(); 581 bool is_ordinary; 582 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); 583 if (is_ordinary 584 && shndx != elfcpp::SHN_UNDEF 585 && !object->is_section_included(shndx)) 586 { 587 // RELOC is a relocation against a local symbol 588 // defined in a section we are discarding. Discard 589 // the reloc. FIXME: Should we issue a warning? 590 strategy = Relocatable_relocs::RELOC_DISCARD; 591 } 592 else if (lsym.get_st_type() != elfcpp::STT_SECTION) 593 strategy = scan.local_non_section_strategy(r_type, object, 594 r_sym); 595 else 596 { 597 strategy = scan.local_section_strategy(r_type, object); 598 if (strategy != Relocatable_relocs::RELOC_DISCARD) 599 object->output_section(shndx)->set_needs_symtab_index(); 600 } 601 602 if (strategy == Relocatable_relocs::RELOC_COPY) 603 object->set_must_have_output_symtab_entry(r_sym); 604 } 605 } 606 607 rr->set_next_reloc_strategy(strategy); 608 } 609 } 610 611 // Relocate relocs. Called for a relocatable link, and for --emit-relocs. 612 // This is a default definition which should work for most targets. 613 614 template<int size, bool big_endian, int sh_type> 615 void 616 relocate_relocs( 617 const Relocate_info<size, big_endian>* relinfo, 618 const unsigned char* prelocs, 619 size_t reloc_count, 620 Output_section* output_section, 621 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, 622 const Relocatable_relocs* rr, 623 unsigned char* view, 624 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 625 section_size_type view_size, 626 unsigned char* reloc_view, 627 section_size_type reloc_view_size) 628 { 629 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; 630 typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; 631 typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write 632 Reltype_write; 633 const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; 634 const Address invalid_address = static_cast<Address>(0) - 1; 635 636 Sized_relobj_file<size, big_endian>* const object = relinfo->object; 637 const unsigned int local_count = object->local_symbol_count(); 638 639 unsigned char* pwrite = reloc_view; 640 641 for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) 642 { 643 Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i); 644 if (strategy == Relocatable_relocs::RELOC_DISCARD) 645 continue; 646 647 if (strategy == Relocatable_relocs::RELOC_SPECIAL) 648 { 649 // Target wants to handle this relocation. 650 Sized_target<size, big_endian>* target = 651 parameters->sized_target<size, big_endian>(); 652 target->relocate_special_relocatable(relinfo, sh_type, prelocs, 653 i, output_section, 654 offset_in_output_section, 655 view, view_address, 656 view_size, pwrite); 657 pwrite += reloc_size; 658 continue; 659 } 660 Reltype reloc(prelocs); 661 Reltype_write reloc_write(pwrite); 662 663 typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); 664 const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); 665 const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); 666 667 // Get the new symbol index. 668 669 unsigned int new_symndx; 670 if (r_sym < local_count) 671 { 672 switch (strategy) 673 { 674 case Relocatable_relocs::RELOC_COPY: 675 if (r_sym == 0) 676 new_symndx = 0; 677 else 678 { 679 new_symndx = object->symtab_index(r_sym); 680 gold_assert(new_symndx != -1U); 681 } 682 break; 683 684 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: 685 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: 686 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: 687 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: 688 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: 689 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: 690 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: 691 { 692 // We are adjusting a section symbol. We need to find 693 // the symbol table index of the section symbol for 694 // the output section corresponding to input section 695 // in which this symbol is defined. 696 gold_assert(r_sym < local_count); 697 bool is_ordinary; 698 unsigned int shndx = 699 object->local_symbol_input_shndx(r_sym, &is_ordinary); 700 gold_assert(is_ordinary); 701 Output_section* os = object->output_section(shndx); 702 gold_assert(os != NULL); 703 gold_assert(os->needs_symtab_index()); 704 new_symndx = os->symtab_index(); 705 } 706 break; 707 708 default: 709 gold_unreachable(); 710 } 711 } 712 else 713 { 714 const Symbol* gsym = object->global_symbol(r_sym); 715 gold_assert(gsym != NULL); 716 if (gsym->is_forwarder()) 717 gsym = relinfo->symtab->resolve_forwards(gsym); 718 719 gold_assert(gsym->has_symtab_index()); 720 new_symndx = gsym->symtab_index(); 721 } 722 723 // Get the new offset--the location in the output section where 724 // this relocation should be applied. 725 726 Address offset = reloc.get_r_offset(); 727 Address new_offset; 728 if (offset_in_output_section != invalid_address) 729 new_offset = offset + offset_in_output_section; 730 else 731 { 732 section_offset_type sot_offset = 733 convert_types<section_offset_type, Address>(offset); 734 section_offset_type new_sot_offset = 735 output_section->output_offset(object, relinfo->data_shndx, 736 sot_offset); 737 gold_assert(new_sot_offset != -1); 738 new_offset = new_sot_offset; 739 } 740 741 // In an object file, r_offset is an offset within the section. 742 // In an executable or dynamic object, generated by 743 // --emit-relocs, r_offset is an absolute address. 744 if (!parameters->options().relocatable()) 745 { 746 new_offset += view_address; 747 if (offset_in_output_section != invalid_address) 748 new_offset -= offset_in_output_section; 749 } 750 751 reloc_write.put_r_offset(new_offset); 752 reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type)); 753 754 // Handle the reloc addend based on the strategy. 755 756 if (strategy == Relocatable_relocs::RELOC_COPY) 757 { 758 if (sh_type == elfcpp::SHT_RELA) 759 Reloc_types<sh_type, size, big_endian>:: 760 copy_reloc_addend(&reloc_write, 761 &reloc); 762 } 763 else 764 { 765 // The relocation uses a section symbol in the input file. 766 // We are adjusting it to use a section symbol in the output 767 // file. The input section symbol refers to some address in 768 // the input section. We need the relocation in the output 769 // file to refer to that same address. This adjustment to 770 // the addend is the same calculation we use for a simple 771 // absolute relocation for the input section symbol. 772 773 const Symbol_value<size>* psymval = object->local_symbol(r_sym); 774 775 unsigned char* padd = view + offset; 776 switch (strategy) 777 { 778 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: 779 { 780 typename elfcpp::Elf_types<size>::Elf_Swxword addend; 781 addend = Reloc_types<sh_type, size, big_endian>:: 782 get_reloc_addend(&reloc); 783 addend = psymval->value(object, addend); 784 Reloc_types<sh_type, size, big_endian>:: 785 set_reloc_addend(&reloc_write, addend); 786 } 787 break; 788 789 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: 790 break; 791 792 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: 793 Relocate_functions<size, big_endian>::rel8(padd, object, 794 psymval); 795 break; 796 797 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: 798 Relocate_functions<size, big_endian>::rel16(padd, object, 799 psymval); 800 break; 801 802 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: 803 Relocate_functions<size, big_endian>::rel32(padd, object, 804 psymval); 805 break; 806 807 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: 808 Relocate_functions<size, big_endian>::rel64(padd, object, 809 psymval); 810 break; 811 812 case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: 813 Relocate_functions<size, big_endian>::rel32_unaligned(padd, 814 object, 815 psymval); 816 break; 817 818 default: 819 gold_unreachable(); 820 } 821 } 822 823 pwrite += reloc_size; 824 } 825 826 gold_assert(static_cast<section_size_type>(pwrite - reloc_view) 827 == reloc_view_size); 828 } 829 830 } // End namespace gold. 831 832 #endif // !defined(GOLD_TARGET_RELOC_H) 833
