1 // x86_64.cc -- x86_64 target support for gold. 2 3 // Copyright (C) 2006-2016 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 "dwarf.h" 29 #include "parameters.h" 30 #include "reloc.h" 31 #include "x86_64.h" 32 #include "object.h" 33 #include "symtab.h" 34 #include "layout.h" 35 #include "output.h" 36 #include "copy-relocs.h" 37 #include "target.h" 38 #include "target-reloc.h" 39 #include "target-select.h" 40 #include "tls.h" 41 #include "freebsd.h" 42 #include "nacl.h" 43 #include "gc.h" 44 #include "icf.h" 45 46 namespace 47 { 48 49 using namespace gold; 50 51 // A class to handle the .got.plt section. 52 53 class Output_data_got_plt_x86_64 : public Output_section_data_build 54 { 55 public: 56 Output_data_got_plt_x86_64(Layout* layout) 57 : Output_section_data_build(8), 58 layout_(layout) 59 { } 60 61 Output_data_got_plt_x86_64(Layout* layout, off_t data_size) 62 : Output_section_data_build(data_size, 8), 63 layout_(layout) 64 { } 65 66 protected: 67 // Write out the PLT data. 68 void 69 do_write(Output_file*); 70 71 // Write to a map file. 72 void 73 do_print_to_mapfile(Mapfile* mapfile) const 74 { mapfile->print_output_data(this, "** GOT PLT"); } 75 76 private: 77 // A pointer to the Layout class, so that we can find the .dynamic 78 // section when we write out the GOT PLT section. 79 Layout* layout_; 80 }; 81 82 // A class to handle the PLT data. 83 // This is an abstract base class that handles most of the linker details 84 // but does not know the actual contents of PLT entries. The derived 85 // classes below fill in those details. 86 87 template<int size> 88 class Output_data_plt_x86_64 : public Output_section_data 89 { 90 public: 91 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; 92 93 Output_data_plt_x86_64(Layout* layout, uint64_t addralign, 94 Output_data_got<64, false>* got, 95 Output_data_got_plt_x86_64* got_plt, 96 Output_data_space* got_irelative) 97 : Output_section_data(addralign), tlsdesc_rel_(NULL), 98 irelative_rel_(NULL), got_(got), got_plt_(got_plt), 99 got_irelative_(got_irelative), count_(0), irelative_count_(0), 100 tlsdesc_got_offset_(-1U), free_list_() 101 { this->init(layout); } 102 103 Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size, 104 Output_data_got<64, false>* got, 105 Output_data_got_plt_x86_64* got_plt, 106 Output_data_space* got_irelative, 107 unsigned int plt_count) 108 : Output_section_data((plt_count + 1) * plt_entry_size, 109 plt_entry_size, false), 110 tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got), 111 got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count), 112 irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_() 113 { 114 this->init(layout); 115 116 // Initialize the free list and reserve the first entry. 117 this->free_list_.init((plt_count + 1) * plt_entry_size, false); 118 this->free_list_.remove(0, plt_entry_size); 119 } 120 121 // Initialize the PLT section. 122 void 123 init(Layout* layout); 124 125 // Add an entry to the PLT. 126 void 127 add_entry(Symbol_table*, Layout*, Symbol* gsym); 128 129 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. 130 unsigned int 131 add_local_ifunc_entry(Symbol_table* symtab, Layout*, 132 Sized_relobj_file<size, false>* relobj, 133 unsigned int local_sym_index); 134 135 // Add the relocation for a PLT entry. 136 void 137 add_relocation(Symbol_table*, Layout*, Symbol* gsym, 138 unsigned int got_offset); 139 140 // Add the reserved TLSDESC_PLT entry to the PLT. 141 void 142 reserve_tlsdesc_entry(unsigned int got_offset) 143 { this->tlsdesc_got_offset_ = got_offset; } 144 145 // Return true if a TLSDESC_PLT entry has been reserved. 146 bool 147 has_tlsdesc_entry() const 148 { return this->tlsdesc_got_offset_ != -1U; } 149 150 // Return the GOT offset for the reserved TLSDESC_PLT entry. 151 unsigned int 152 get_tlsdesc_got_offset() const 153 { return this->tlsdesc_got_offset_; } 154 155 // Return the offset of the reserved TLSDESC_PLT entry. 156 unsigned int 157 get_tlsdesc_plt_offset() const 158 { 159 return ((this->count_ + this->irelative_count_ + 1) 160 * this->get_plt_entry_size()); 161 } 162 163 // Return the .rela.plt section data. 164 Reloc_section* 165 rela_plt() 166 { return this->rel_; } 167 168 // Return where the TLSDESC relocations should go. 169 Reloc_section* 170 rela_tlsdesc(Layout*); 171 172 // Return where the IRELATIVE relocations should go in the PLT 173 // relocations. 174 Reloc_section* 175 rela_irelative(Symbol_table*, Layout*); 176 177 // Return whether we created a section for IRELATIVE relocations. 178 bool 179 has_irelative_section() const 180 { return this->irelative_rel_ != NULL; } 181 182 // Return the number of PLT entries. 183 unsigned int 184 entry_count() const 185 { return this->count_ + this->irelative_count_; } 186 187 // Return the offset of the first non-reserved PLT entry. 188 unsigned int 189 first_plt_entry_offset() 190 { return this->get_plt_entry_size(); } 191 192 // Return the size of a PLT entry. 193 unsigned int 194 get_plt_entry_size() const 195 { return this->do_get_plt_entry_size(); } 196 197 // Reserve a slot in the PLT for an existing symbol in an incremental update. 198 void 199 reserve_slot(unsigned int plt_index) 200 { 201 this->free_list_.remove((plt_index + 1) * this->get_plt_entry_size(), 202 (plt_index + 2) * this->get_plt_entry_size()); 203 } 204 205 // Return the PLT address to use for a global symbol. 206 uint64_t 207 address_for_global(const Symbol*); 208 209 // Return the PLT address to use for a local symbol. 210 uint64_t 211 address_for_local(const Relobj*, unsigned int symndx); 212 213 // Add .eh_frame information for the PLT. 214 void 215 add_eh_frame(Layout* layout) 216 { this->do_add_eh_frame(layout); } 217 218 protected: 219 // Fill in the first PLT entry. 220 void 221 fill_first_plt_entry(unsigned char* pov, 222 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 223 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 224 { this->do_fill_first_plt_entry(pov, got_address, plt_address); } 225 226 // Fill in a normal PLT entry. Returns the offset into the entry that 227 // should be the initial GOT slot value. 228 unsigned int 229 fill_plt_entry(unsigned char* pov, 230 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 231 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 232 unsigned int got_offset, 233 unsigned int plt_offset, 234 unsigned int plt_index) 235 { 236 return this->do_fill_plt_entry(pov, got_address, plt_address, 237 got_offset, plt_offset, plt_index); 238 } 239 240 // Fill in the reserved TLSDESC PLT entry. 241 void 242 fill_tlsdesc_entry(unsigned char* pov, 243 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 244 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 245 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 246 unsigned int tlsdesc_got_offset, 247 unsigned int plt_offset) 248 { 249 this->do_fill_tlsdesc_entry(pov, got_address, plt_address, got_base, 250 tlsdesc_got_offset, plt_offset); 251 } 252 253 virtual unsigned int 254 do_get_plt_entry_size() const = 0; 255 256 virtual void 257 do_fill_first_plt_entry(unsigned char* pov, 258 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 259 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr) 260 = 0; 261 262 virtual unsigned int 263 do_fill_plt_entry(unsigned char* pov, 264 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 265 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 266 unsigned int got_offset, 267 unsigned int plt_offset, 268 unsigned int plt_index) = 0; 269 270 virtual void 271 do_fill_tlsdesc_entry(unsigned char* pov, 272 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 273 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 274 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 275 unsigned int tlsdesc_got_offset, 276 unsigned int plt_offset) = 0; 277 278 virtual void 279 do_add_eh_frame(Layout* layout) = 0; 280 281 void 282 do_adjust_output_section(Output_section* os); 283 284 // Write to a map file. 285 void 286 do_print_to_mapfile(Mapfile* mapfile) const 287 { mapfile->print_output_data(this, _("** PLT")); } 288 289 // The CIE of the .eh_frame unwind information for the PLT. 290 static const int plt_eh_frame_cie_size = 16; 291 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; 292 293 private: 294 // Set the final size. 295 void 296 set_final_data_size(); 297 298 // Write out the PLT data. 299 void 300 do_write(Output_file*); 301 302 // The reloc section. 303 Reloc_section* rel_; 304 // The TLSDESC relocs, if necessary. These must follow the regular 305 // PLT relocs. 306 Reloc_section* tlsdesc_rel_; 307 // The IRELATIVE relocs, if necessary. These must follow the 308 // regular PLT relocations and the TLSDESC relocations. 309 Reloc_section* irelative_rel_; 310 // The .got section. 311 Output_data_got<64, false>* got_; 312 // The .got.plt section. 313 Output_data_got_plt_x86_64* got_plt_; 314 // The part of the .got.plt section used for IRELATIVE relocs. 315 Output_data_space* got_irelative_; 316 // The number of PLT entries. 317 unsigned int count_; 318 // Number of PLT entries with R_X86_64_IRELATIVE relocs. These 319 // follow the regular PLT entries. 320 unsigned int irelative_count_; 321 // Offset of the reserved TLSDESC_GOT entry when needed. 322 unsigned int tlsdesc_got_offset_; 323 // List of available regions within the section, for incremental 324 // update links. 325 Free_list free_list_; 326 }; 327 328 template<int size> 329 class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size> 330 { 331 public: 332 Output_data_plt_x86_64_standard(Layout* layout, 333 Output_data_got<64, false>* got, 334 Output_data_got_plt_x86_64* got_plt, 335 Output_data_space* got_irelative) 336 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 337 got, got_plt, got_irelative) 338 { } 339 340 Output_data_plt_x86_64_standard(Layout* layout, 341 Output_data_got<64, false>* got, 342 Output_data_got_plt_x86_64* got_plt, 343 Output_data_space* got_irelative, 344 unsigned int plt_count) 345 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 346 got, got_plt, got_irelative, 347 plt_count) 348 { } 349 350 protected: 351 virtual unsigned int 352 do_get_plt_entry_size() const 353 { return plt_entry_size; } 354 355 virtual void 356 do_add_eh_frame(Layout* layout) 357 { 358 layout->add_eh_frame_for_plt(this, 359 this->plt_eh_frame_cie, 360 this->plt_eh_frame_cie_size, 361 plt_eh_frame_fde, 362 plt_eh_frame_fde_size); 363 } 364 365 virtual void 366 do_fill_first_plt_entry(unsigned char* pov, 367 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 368 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); 369 370 virtual unsigned int 371 do_fill_plt_entry(unsigned char* pov, 372 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 373 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 374 unsigned int got_offset, 375 unsigned int plt_offset, 376 unsigned int plt_index); 377 378 virtual void 379 do_fill_tlsdesc_entry(unsigned char* pov, 380 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 381 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 382 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 383 unsigned int tlsdesc_got_offset, 384 unsigned int plt_offset); 385 386 private: 387 // The size of an entry in the PLT. 388 static const int plt_entry_size = 16; 389 390 // The first entry in the PLT. 391 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same 392 // procedure linkage table for both programs and shared objects." 393 static const unsigned char first_plt_entry[plt_entry_size]; 394 395 // Other entries in the PLT for an executable. 396 static const unsigned char plt_entry[plt_entry_size]; 397 398 // The reserved TLSDESC entry in the PLT for an executable. 399 static const unsigned char tlsdesc_plt_entry[plt_entry_size]; 400 401 // The .eh_frame unwind information for the PLT. 402 static const int plt_eh_frame_fde_size = 32; 403 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; 404 }; 405 406 template<int size> 407 class Lazy_view 408 { 409 public: 410 Lazy_view(Sized_relobj_file<size, false>* object, unsigned int data_shndx) 411 : object_(object), data_shndx_(data_shndx), view_(NULL), view_size_(0) 412 { } 413 414 inline unsigned char 415 operator[](size_t offset) 416 { 417 if (this->view_ == NULL) 418 this->view_ = this->object_->section_contents(this->data_shndx_, 419 &this->view_size_, 420 true); 421 if (offset >= this->view_size_) 422 return 0; 423 return this->view_[offset]; 424 } 425 426 private: 427 Sized_relobj_file<size, false>* object_; 428 unsigned int data_shndx_; 429 const unsigned char* view_; 430 section_size_type view_size_; 431 }; 432 433 // The x86_64 target class. 434 // See the ABI at 435 // http://www.x86-64.org/documentation/abi.pdf 436 // TLS info comes from 437 // http://people.redhat.com/drepper/tls.pdf 438 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt 439 440 template<int size> 441 class Target_x86_64 : public Sized_target<size, false> 442 { 443 public: 444 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures 445 // uses only Elf64_Rela relocation entries with explicit addends." 446 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; 447 448 Target_x86_64(const Target::Target_info* info = &x86_64_info) 449 : Sized_target<size, false>(info), 450 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), 451 got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL), 452 rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), 453 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(), 454 tls_base_symbol_defined_(false) 455 { } 456 457 // Hook for a new output section. 458 void 459 do_new_output_section(Output_section*) const; 460 461 // Scan the relocations to look for symbol adjustments. 462 void 463 gc_process_relocs(Symbol_table* symtab, 464 Layout* layout, 465 Sized_relobj_file<size, false>* object, 466 unsigned int data_shndx, 467 unsigned int sh_type, 468 const unsigned char* prelocs, 469 size_t reloc_count, 470 Output_section* output_section, 471 bool needs_special_offset_handling, 472 size_t local_symbol_count, 473 const unsigned char* plocal_symbols); 474 475 // Scan the relocations to look for symbol adjustments. 476 void 477 scan_relocs(Symbol_table* symtab, 478 Layout* layout, 479 Sized_relobj_file<size, false>* object, 480 unsigned int data_shndx, 481 unsigned int sh_type, 482 const unsigned char* prelocs, 483 size_t reloc_count, 484 Output_section* output_section, 485 bool needs_special_offset_handling, 486 size_t local_symbol_count, 487 const unsigned char* plocal_symbols); 488 489 // Finalize the sections. 490 void 491 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); 492 493 // Return the value to use for a dynamic which requires special 494 // treatment. 495 uint64_t 496 do_dynsym_value(const Symbol*) const; 497 498 // Relocate a section. 499 void 500 relocate_section(const Relocate_info<size, false>*, 501 unsigned int sh_type, 502 const unsigned char* prelocs, 503 size_t reloc_count, 504 Output_section* output_section, 505 bool needs_special_offset_handling, 506 unsigned char* view, 507 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 508 section_size_type view_size, 509 const Reloc_symbol_changes*); 510 511 // Scan the relocs during a relocatable link. 512 void 513 scan_relocatable_relocs(Symbol_table* symtab, 514 Layout* layout, 515 Sized_relobj_file<size, false>* object, 516 unsigned int data_shndx, 517 unsigned int sh_type, 518 const unsigned char* prelocs, 519 size_t reloc_count, 520 Output_section* output_section, 521 bool needs_special_offset_handling, 522 size_t local_symbol_count, 523 const unsigned char* plocal_symbols, 524 Relocatable_relocs*); 525 526 // Scan the relocs for --emit-relocs. 527 void 528 emit_relocs_scan(Symbol_table* symtab, 529 Layout* layout, 530 Sized_relobj_file<size, false>* object, 531 unsigned int data_shndx, 532 unsigned int sh_type, 533 const unsigned char* prelocs, 534 size_t reloc_count, 535 Output_section* output_section, 536 bool needs_special_offset_handling, 537 size_t local_symbol_count, 538 const unsigned char* plocal_syms, 539 Relocatable_relocs* rr); 540 541 // Emit relocations for a section. 542 void 543 relocate_relocs( 544 const Relocate_info<size, false>*, 545 unsigned int sh_type, 546 const unsigned char* prelocs, 547 size_t reloc_count, 548 Output_section* output_section, 549 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, 550 unsigned char* view, 551 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 552 section_size_type view_size, 553 unsigned char* reloc_view, 554 section_size_type reloc_view_size); 555 556 // Return a string used to fill a code section with nops. 557 std::string 558 do_code_fill(section_size_type length) const; 559 560 // Return whether SYM is defined by the ABI. 561 bool 562 do_is_defined_by_abi(const Symbol* sym) const 563 { return strcmp(sym->name(), "__tls_get_addr") == 0; } 564 565 // Return the symbol index to use for a target specific relocation. 566 // The only target specific relocation is R_X86_64_TLSDESC for a 567 // local symbol, which is an absolute reloc. 568 unsigned int 569 do_reloc_symbol_index(void*, unsigned int r_type) const 570 { 571 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); 572 return 0; 573 } 574 575 // Return the addend to use for a target specific relocation. 576 uint64_t 577 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const; 578 579 // Return the PLT section. 580 uint64_t 581 do_plt_address_for_global(const Symbol* gsym) const 582 { return this->plt_section()->address_for_global(gsym); } 583 584 uint64_t 585 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const 586 { return this->plt_section()->address_for_local(relobj, symndx); } 587 588 // This function should be defined in targets that can use relocation 589 // types to determine (implemented in local_reloc_may_be_function_pointer 590 // and global_reloc_may_be_function_pointer) 591 // if a function's pointer is taken. ICF uses this in safe mode to only 592 // fold those functions whose pointer is defintely not taken. For x86_64 593 // pie binaries, safe ICF cannot be done by looking at relocation types. 594 bool 595 do_can_check_for_function_pointers() const 596 { return !parameters->options().pie(); } 597 598 // Return the base for a DW_EH_PE_datarel encoding. 599 uint64_t 600 do_ehframe_datarel_base() const; 601 602 // Adjust -fsplit-stack code which calls non-split-stack code. 603 void 604 do_calls_non_split(Relobj* object, unsigned int shndx, 605 section_offset_type fnoffset, section_size_type fnsize, 606 const unsigned char* prelocs, size_t reloc_count, 607 unsigned char* view, section_size_type view_size, 608 std::string* from, std::string* to) const; 609 610 // Return the size of the GOT section. 611 section_size_type 612 got_size() const 613 { 614 gold_assert(this->got_ != NULL); 615 return this->got_->data_size(); 616 } 617 618 // Return the number of entries in the GOT. 619 unsigned int 620 got_entry_count() const 621 { 622 if (this->got_ == NULL) 623 return 0; 624 return this->got_size() / 8; 625 } 626 627 // Return the number of entries in the PLT. 628 unsigned int 629 plt_entry_count() const; 630 631 // Return the offset of the first non-reserved PLT entry. 632 unsigned int 633 first_plt_entry_offset() const; 634 635 // Return the size of each PLT entry. 636 unsigned int 637 plt_entry_size() const; 638 639 // Return the size of each GOT entry. 640 unsigned int 641 got_entry_size() const 642 { return 8; }; 643 644 // Create the GOT section for an incremental update. 645 Output_data_got_base* 646 init_got_plt_for_update(Symbol_table* symtab, 647 Layout* layout, 648 unsigned int got_count, 649 unsigned int plt_count); 650 651 // Reserve a GOT entry for a local symbol, and regenerate any 652 // necessary dynamic relocations. 653 void 654 reserve_local_got_entry(unsigned int got_index, 655 Sized_relobj<size, false>* obj, 656 unsigned int r_sym, 657 unsigned int got_type); 658 659 // Reserve a GOT entry for a global symbol, and regenerate any 660 // necessary dynamic relocations. 661 void 662 reserve_global_got_entry(unsigned int got_index, Symbol* gsym, 663 unsigned int got_type); 664 665 // Register an existing PLT entry for a global symbol. 666 void 667 register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index, 668 Symbol* gsym); 669 670 // Force a COPY relocation for a given symbol. 671 void 672 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t); 673 674 // Apply an incremental relocation. 675 void 676 apply_relocation(const Relocate_info<size, false>* relinfo, 677 typename elfcpp::Elf_types<size>::Elf_Addr r_offset, 678 unsigned int r_type, 679 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, 680 const Symbol* gsym, 681 unsigned char* view, 682 typename elfcpp::Elf_types<size>::Elf_Addr address, 683 section_size_type view_size); 684 685 // Add a new reloc argument, returning the index in the vector. 686 size_t 687 add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym) 688 { 689 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym)); 690 return this->tlsdesc_reloc_info_.size() - 1; 691 } 692 693 Output_data_plt_x86_64<size>* 694 make_data_plt(Layout* layout, 695 Output_data_got<64, false>* got, 696 Output_data_got_plt_x86_64* got_plt, 697 Output_data_space* got_irelative) 698 { 699 return this->do_make_data_plt(layout, got, got_plt, got_irelative); 700 } 701 702 Output_data_plt_x86_64<size>* 703 make_data_plt(Layout* layout, 704 Output_data_got<64, false>* got, 705 Output_data_got_plt_x86_64* got_plt, 706 Output_data_space* got_irelative, 707 unsigned int plt_count) 708 { 709 return this->do_make_data_plt(layout, got, got_plt, got_irelative, 710 plt_count); 711 } 712 713 virtual Output_data_plt_x86_64<size>* 714 do_make_data_plt(Layout* layout, 715 Output_data_got<64, false>* got, 716 Output_data_got_plt_x86_64* got_plt, 717 Output_data_space* got_irelative) 718 { 719 return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt, 720 got_irelative); 721 } 722 723 virtual Output_data_plt_x86_64<size>* 724 do_make_data_plt(Layout* layout, 725 Output_data_got<64, false>* got, 726 Output_data_got_plt_x86_64* got_plt, 727 Output_data_space* got_irelative, 728 unsigned int plt_count) 729 { 730 return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt, 731 got_irelative, 732 plt_count); 733 } 734 735 private: 736 // The class which scans relocations. 737 class Scan 738 { 739 public: 740 Scan() 741 : issued_non_pic_error_(false) 742 { } 743 744 static inline int 745 get_reference_flags(unsigned int r_type); 746 747 inline void 748 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, 749 Sized_relobj_file<size, false>* object, 750 unsigned int data_shndx, 751 Output_section* output_section, 752 const elfcpp::Rela<size, false>& reloc, unsigned int r_type, 753 const elfcpp::Sym<size, false>& lsym, 754 bool is_discarded); 755 756 inline void 757 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, 758 Sized_relobj_file<size, false>* object, 759 unsigned int data_shndx, 760 Output_section* output_section, 761 const elfcpp::Rela<size, false>& reloc, unsigned int r_type, 762 Symbol* gsym); 763 764 inline bool 765 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, 766 Target_x86_64* target, 767 Sized_relobj_file<size, false>* object, 768 unsigned int data_shndx, 769 Output_section* output_section, 770 const elfcpp::Rela<size, false>& reloc, 771 unsigned int r_type, 772 const elfcpp::Sym<size, false>& lsym); 773 774 inline bool 775 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, 776 Target_x86_64* target, 777 Sized_relobj_file<size, false>* object, 778 unsigned int data_shndx, 779 Output_section* output_section, 780 const elfcpp::Rela<size, false>& reloc, 781 unsigned int r_type, 782 Symbol* gsym); 783 784 private: 785 static void 786 unsupported_reloc_local(Sized_relobj_file<size, false>*, 787 unsigned int r_type); 788 789 static void 790 unsupported_reloc_global(Sized_relobj_file<size, false>*, 791 unsigned int r_type, Symbol*); 792 793 void 794 check_non_pic(Relobj*, unsigned int r_type, Symbol*); 795 796 inline bool 797 possible_function_pointer_reloc(unsigned int r_type); 798 799 bool 800 reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*, 801 unsigned int r_type); 802 803 // Whether we have issued an error about a non-PIC compilation. 804 bool issued_non_pic_error_; 805 }; 806 807 // The class which implements relocation. 808 class Relocate 809 { 810 public: 811 Relocate() 812 : skip_call_tls_get_addr_(false) 813 { } 814 815 ~Relocate() 816 { 817 if (this->skip_call_tls_get_addr_) 818 { 819 // FIXME: This needs to specify the location somehow. 820 gold_error(_("missing expected TLS relocation")); 821 } 822 } 823 824 // Do a relocation. Return false if the caller should not issue 825 // any warnings about this relocation. 826 inline bool 827 relocate(const Relocate_info<size, false>*, unsigned int, 828 Target_x86_64*, Output_section*, size_t, const unsigned char*, 829 const Sized_symbol<size>*, const Symbol_value<size>*, 830 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, 831 section_size_type); 832 833 private: 834 // Do a TLS relocation. 835 inline void 836 relocate_tls(const Relocate_info<size, false>*, Target_x86_64*, 837 size_t relnum, const elfcpp::Rela<size, false>&, 838 unsigned int r_type, const Sized_symbol<size>*, 839 const Symbol_value<size>*, 840 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, 841 section_size_type); 842 843 // Do a TLS General-Dynamic to Initial-Exec transition. 844 inline void 845 tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, 846 const elfcpp::Rela<size, false>&, unsigned int r_type, 847 typename elfcpp::Elf_types<size>::Elf_Addr value, 848 unsigned char* view, 849 typename elfcpp::Elf_types<size>::Elf_Addr, 850 section_size_type view_size); 851 852 // Do a TLS General-Dynamic to Local-Exec transition. 853 inline void 854 tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum, 855 Output_segment* tls_segment, 856 const elfcpp::Rela<size, false>&, unsigned int r_type, 857 typename elfcpp::Elf_types<size>::Elf_Addr value, 858 unsigned char* view, 859 section_size_type view_size); 860 861 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. 862 inline void 863 tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, 864 const elfcpp::Rela<size, false>&, unsigned int r_type, 865 typename elfcpp::Elf_types<size>::Elf_Addr value, 866 unsigned char* view, 867 typename elfcpp::Elf_types<size>::Elf_Addr, 868 section_size_type view_size); 869 870 // Do a TLSDESC-style General-Dynamic to Local-Exec transition. 871 inline void 872 tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum, 873 Output_segment* tls_segment, 874 const elfcpp::Rela<size, false>&, unsigned int r_type, 875 typename elfcpp::Elf_types<size>::Elf_Addr value, 876 unsigned char* view, 877 section_size_type view_size); 878 879 // Do a TLS Local-Dynamic to Local-Exec transition. 880 inline void 881 tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum, 882 Output_segment* tls_segment, 883 const elfcpp::Rela<size, false>&, unsigned int r_type, 884 typename elfcpp::Elf_types<size>::Elf_Addr value, 885 unsigned char* view, 886 section_size_type view_size); 887 888 // Do a TLS Initial-Exec to Local-Exec transition. 889 static inline void 890 tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum, 891 Output_segment* tls_segment, 892 const elfcpp::Rela<size, false>&, unsigned int r_type, 893 typename elfcpp::Elf_types<size>::Elf_Addr value, 894 unsigned char* view, 895 section_size_type view_size); 896 897 // This is set if we should skip the next reloc, which should be a 898 // PLT32 reloc against ___tls_get_addr. 899 bool skip_call_tls_get_addr_; 900 }; 901 902 // Check if relocation against this symbol is a candidate for 903 // conversion from 904 // mov foo@GOTPCREL(%rip), %reg 905 // to lea foo(%rip), %reg. 906 template<class View_type> 907 static inline bool 908 can_convert_mov_to_lea(const Symbol* gsym, unsigned int r_type, 909 size_t r_offset, View_type* view) 910 { 911 gold_assert(gsym != NULL); 912 // We cannot do the conversion unless it's one of these relocations. 913 if (r_type != elfcpp::R_X86_64_GOTPCREL 914 && r_type != elfcpp::R_X86_64_GOTPCRELX 915 && r_type != elfcpp::R_X86_64_REX_GOTPCRELX) 916 return false; 917 // We cannot convert references to IFUNC symbols, or to symbols that 918 // are not local to the current module. 919 if (gsym->type() == elfcpp::STT_GNU_IFUNC 920 || gsym->is_undefined () 921 || gsym->is_from_dynobj() 922 || gsym->is_preemptible()) 923 return false; 924 // If we are building a shared object and the symbol is protected, we may 925 // need to go through the GOT. 926 if (parameters->options().shared() 927 && gsym->visibility() == elfcpp::STV_PROTECTED) 928 return false; 929 // We cannot convert references to the _DYNAMIC symbol. 930 if (strcmp(gsym->name(), "_DYNAMIC") == 0) 931 return false; 932 // Check for a MOV opcode. 933 return (*view)[r_offset - 2] == 0x8b; 934 } 935 936 // Convert 937 // callq *foo@GOTPCRELX(%rip) to 938 // addr32 callq foo 939 // and jmpq *foo@GOTPCRELX(%rip) to 940 // jmpq foo 941 // nop 942 template<class View_type> 943 static inline bool 944 can_convert_callq_to_direct(const Symbol* gsym, unsigned int r_type, 945 size_t r_offset, View_type* view) 946 { 947 gold_assert(gsym != NULL); 948 // We cannot do the conversion unless it's a GOTPCRELX relocation. 949 if (r_type != elfcpp::R_X86_64_GOTPCRELX) 950 return false; 951 // We cannot convert references to IFUNC symbols, or to symbols that 952 // are not local to the current module. 953 if (gsym->type() == elfcpp::STT_GNU_IFUNC 954 || gsym->is_undefined () 955 || gsym->is_from_dynobj() 956 || gsym->is_preemptible()) 957 return false; 958 // Check for a CALLQ or JMPQ opcode. 959 return ((*view)[r_offset - 2] == 0xff 960 && ((*view)[r_offset - 1] == 0x15 961 || (*view)[r_offset - 1] == 0x25)); 962 } 963 964 // Adjust TLS relocation type based on the options and whether this 965 // is a local symbol. 966 static tls::Tls_optimization 967 optimize_tls_reloc(bool is_final, int r_type); 968 969 // Get the GOT section, creating it if necessary. 970 Output_data_got<64, false>* 971 got_section(Symbol_table*, Layout*); 972 973 // Get the GOT PLT section. 974 Output_data_got_plt_x86_64* 975 got_plt_section() const 976 { 977 gold_assert(this->got_plt_ != NULL); 978 return this->got_plt_; 979 } 980 981 // Get the GOT section for TLSDESC entries. 982 Output_data_got<64, false>* 983 got_tlsdesc_section() const 984 { 985 gold_assert(this->got_tlsdesc_ != NULL); 986 return this->got_tlsdesc_; 987 } 988 989 // Create the PLT section. 990 void 991 make_plt_section(Symbol_table* symtab, Layout* layout); 992 993 // Create a PLT entry for a global symbol. 994 void 995 make_plt_entry(Symbol_table*, Layout*, Symbol*); 996 997 // Create a PLT entry for a local STT_GNU_IFUNC symbol. 998 void 999 make_local_ifunc_plt_entry(Symbol_table*, Layout*, 1000 Sized_relobj_file<size, false>* relobj, 1001 unsigned int local_sym_index); 1002 1003 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. 1004 void 1005 define_tls_base_symbol(Symbol_table*, Layout*); 1006 1007 // Create the reserved PLT and GOT entries for the TLS descriptor resolver. 1008 void 1009 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout); 1010 1011 // Create a GOT entry for the TLS module index. 1012 unsigned int 1013 got_mod_index_entry(Symbol_table* symtab, Layout* layout, 1014 Sized_relobj_file<size, false>* object); 1015 1016 // Get the PLT section. 1017 Output_data_plt_x86_64<size>* 1018 plt_section() const 1019 { 1020 gold_assert(this->plt_ != NULL); 1021 return this->plt_; 1022 } 1023 1024 // Get the dynamic reloc section, creating it if necessary. 1025 Reloc_section* 1026 rela_dyn_section(Layout*); 1027 1028 // Get the section to use for TLSDESC relocations. 1029 Reloc_section* 1030 rela_tlsdesc_section(Layout*) const; 1031 1032 // Get the section to use for IRELATIVE relocations. 1033 Reloc_section* 1034 rela_irelative_section(Layout*); 1035 1036 // Add a potential copy relocation. 1037 void 1038 copy_reloc(Symbol_table* symtab, Layout* layout, 1039 Sized_relobj_file<size, false>* object, 1040 unsigned int shndx, Output_section* output_section, 1041 Symbol* sym, const elfcpp::Rela<size, false>& reloc) 1042 { 1043 unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info()); 1044 this->copy_relocs_.copy_reloc(symtab, layout, 1045 symtab->get_sized_symbol<size>(sym), 1046 object, shndx, output_section, 1047 r_type, reloc.get_r_offset(), 1048 reloc.get_r_addend(), 1049 this->rela_dyn_section(layout)); 1050 } 1051 1052 // Information about this specific target which we pass to the 1053 // general Target structure. 1054 static const Target::Target_info x86_64_info; 1055 1056 // The types of GOT entries needed for this platform. 1057 // These values are exposed to the ABI in an incremental link. 1058 // Do not renumber existing values without changing the version 1059 // number of the .gnu_incremental_inputs section. 1060 enum Got_type 1061 { 1062 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol 1063 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset 1064 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair 1065 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair 1066 }; 1067 1068 // This type is used as the argument to the target specific 1069 // relocation routines. The only target specific reloc is 1070 // R_X86_64_TLSDESC against a local symbol. 1071 struct Tlsdesc_info 1072 { 1073 Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym) 1074 : object(a_object), r_sym(a_r_sym) 1075 { } 1076 1077 // The object in which the local symbol is defined. 1078 Sized_relobj_file<size, false>* object; 1079 // The local symbol index in the object. 1080 unsigned int r_sym; 1081 }; 1082 1083 // The GOT section. 1084 Output_data_got<64, false>* got_; 1085 // The PLT section. 1086 Output_data_plt_x86_64<size>* plt_; 1087 // The GOT PLT section. 1088 Output_data_got_plt_x86_64* got_plt_; 1089 // The GOT section for IRELATIVE relocations. 1090 Output_data_space* got_irelative_; 1091 // The GOT section for TLSDESC relocations. 1092 Output_data_got<64, false>* got_tlsdesc_; 1093 // The _GLOBAL_OFFSET_TABLE_ symbol. 1094 Symbol* global_offset_table_; 1095 // The dynamic reloc section. 1096 Reloc_section* rela_dyn_; 1097 // The section to use for IRELATIVE relocs. 1098 Reloc_section* rela_irelative_; 1099 // Relocs saved to avoid a COPY reloc. 1100 Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_; 1101 // Offset of the GOT entry for the TLS module index. 1102 unsigned int got_mod_index_offset_; 1103 // We handle R_X86_64_TLSDESC against a local symbol as a target 1104 // specific relocation. Here we store the object and local symbol 1105 // index for the relocation. 1106 std::vector<Tlsdesc_info> tlsdesc_reloc_info_; 1107 // True if the _TLS_MODULE_BASE_ symbol has been defined. 1108 bool tls_base_symbol_defined_; 1109 }; 1110 1111 template<> 1112 const Target::Target_info Target_x86_64<64>::x86_64_info = 1113 { 1114 64, // size 1115 false, // is_big_endian 1116 elfcpp::EM_X86_64, // machine_code 1117 false, // has_make_symbol 1118 false, // has_resolve 1119 true, // has_code_fill 1120 true, // is_default_stack_executable 1121 true, // can_icf_inline_merge_sections 1122 '\0', // wrap_char 1123 "/libexec/ld-elf.so.2", // program interpreter 1124 0x400000, // default_text_segment_address 1125 0x1000, // abi_pagesize (overridable by -z max-page-size) 1126 0x1000, // common_pagesize (overridable by -z common-page-size) 1127 false, // isolate_execinstr 1128 0, // rosegment_gap 1129 elfcpp::SHN_UNDEF, // small_common_shndx 1130 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 1131 0, // small_common_section_flags 1132 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 1133 NULL, // attributes_section 1134 NULL, // attributes_vendor 1135 "_start", // entry_symbol_name 1136 32, // hash_entry_size 1137 }; 1138 1139 template<> 1140 const Target::Target_info Target_x86_64<32>::x86_64_info = 1141 { 1142 32, // size 1143 false, // is_big_endian 1144 elfcpp::EM_X86_64, // machine_code 1145 false, // has_make_symbol 1146 false, // has_resolve 1147 true, // has_code_fill 1148 true, // is_default_stack_executable 1149 true, // can_icf_inline_merge_sections 1150 '\0', // wrap_char 1151 "/libx32/ldx32.so.1", // program interpreter 1152 0x400000, // default_text_segment_address 1153 0x1000, // abi_pagesize (overridable by -z max-page-size) 1154 0x1000, // common_pagesize (overridable by -z common-page-size) 1155 false, // isolate_execinstr 1156 0, // rosegment_gap 1157 elfcpp::SHN_UNDEF, // small_common_shndx 1158 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 1159 0, // small_common_section_flags 1160 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 1161 NULL, // attributes_section 1162 NULL, // attributes_vendor 1163 "_start", // entry_symbol_name 1164 32, // hash_entry_size 1165 }; 1166 1167 // This is called when a new output section is created. This is where 1168 // we handle the SHF_X86_64_LARGE. 1169 1170 template<int size> 1171 void 1172 Target_x86_64<size>::do_new_output_section(Output_section* os) const 1173 { 1174 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0) 1175 os->set_is_large_section(); 1176 } 1177 1178 // Get the GOT section, creating it if necessary. 1179 1180 template<int size> 1181 Output_data_got<64, false>* 1182 Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout) 1183 { 1184 if (this->got_ == NULL) 1185 { 1186 gold_assert(symtab != NULL && layout != NULL); 1187 1188 // When using -z now, we can treat .got.plt as a relro section. 1189 // Without -z now, it is modified after program startup by lazy 1190 // PLT relocations. 1191 bool is_got_plt_relro = parameters->options().now(); 1192 Output_section_order got_order = (is_got_plt_relro 1193 ? ORDER_RELRO 1194 : ORDER_RELRO_LAST); 1195 Output_section_order got_plt_order = (is_got_plt_relro 1196 ? ORDER_RELRO 1197 : ORDER_NON_RELRO_FIRST); 1198 1199 this->got_ = new Output_data_got<64, false>(); 1200 1201 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, 1202 (elfcpp::SHF_ALLOC 1203 | elfcpp::SHF_WRITE), 1204 this->got_, got_order, true); 1205 1206 this->got_plt_ = new Output_data_got_plt_x86_64(layout); 1207 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1208 (elfcpp::SHF_ALLOC 1209 | elfcpp::SHF_WRITE), 1210 this->got_plt_, got_plt_order, 1211 is_got_plt_relro); 1212 1213 // The first three entries are reserved. 1214 this->got_plt_->set_current_data_size(3 * 8); 1215 1216 if (!is_got_plt_relro) 1217 { 1218 // Those bytes can go into the relro segment. 1219 layout->increase_relro(3 * 8); 1220 } 1221 1222 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. 1223 this->global_offset_table_ = 1224 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, 1225 Symbol_table::PREDEFINED, 1226 this->got_plt_, 1227 0, 0, elfcpp::STT_OBJECT, 1228 elfcpp::STB_LOCAL, 1229 elfcpp::STV_HIDDEN, 0, 1230 false, false); 1231 1232 // If there are any IRELATIVE relocations, they get GOT entries 1233 // in .got.plt after the jump slot entries. 1234 this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT"); 1235 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1236 (elfcpp::SHF_ALLOC 1237 | elfcpp::SHF_WRITE), 1238 this->got_irelative_, 1239 got_plt_order, is_got_plt_relro); 1240 1241 // If there are any TLSDESC relocations, they get GOT entries in 1242 // .got.plt after the jump slot and IRELATIVE entries. 1243 this->got_tlsdesc_ = new Output_data_got<64, false>(); 1244 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1245 (elfcpp::SHF_ALLOC 1246 | elfcpp::SHF_WRITE), 1247 this->got_tlsdesc_, 1248 got_plt_order, is_got_plt_relro); 1249 } 1250 1251 return this->got_; 1252 } 1253 1254 // Get the dynamic reloc section, creating it if necessary. 1255 1256 template<int size> 1257 typename Target_x86_64<size>::Reloc_section* 1258 Target_x86_64<size>::rela_dyn_section(Layout* layout) 1259 { 1260 if (this->rela_dyn_ == NULL) 1261 { 1262 gold_assert(layout != NULL); 1263 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc()); 1264 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, 1265 elfcpp::SHF_ALLOC, this->rela_dyn_, 1266 ORDER_DYNAMIC_RELOCS, false); 1267 } 1268 return this->rela_dyn_; 1269 } 1270 1271 // Get the section to use for IRELATIVE relocs, creating it if 1272 // necessary. These go in .rela.dyn, but only after all other dynamic 1273 // relocations. They need to follow the other dynamic relocations so 1274 // that they can refer to global variables initialized by those 1275 // relocs. 1276 1277 template<int size> 1278 typename Target_x86_64<size>::Reloc_section* 1279 Target_x86_64<size>::rela_irelative_section(Layout* layout) 1280 { 1281 if (this->rela_irelative_ == NULL) 1282 { 1283 // Make sure we have already created the dynamic reloc section. 1284 this->rela_dyn_section(layout); 1285 this->rela_irelative_ = new Reloc_section(false); 1286 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, 1287 elfcpp::SHF_ALLOC, this->rela_irelative_, 1288 ORDER_DYNAMIC_RELOCS, false); 1289 gold_assert(this->rela_dyn_->output_section() 1290 == this->rela_irelative_->output_section()); 1291 } 1292 return this->rela_irelative_; 1293 } 1294 1295 // Write the first three reserved words of the .got.plt section. 1296 // The remainder of the section is written while writing the PLT 1297 // in Output_data_plt_i386::do_write. 1298 1299 void 1300 Output_data_got_plt_x86_64::do_write(Output_file* of) 1301 { 1302 // The first entry in the GOT is the address of the .dynamic section 1303 // aka the PT_DYNAMIC segment. The next two entries are reserved. 1304 // We saved space for them when we created the section in 1305 // Target_x86_64::got_section. 1306 const off_t got_file_offset = this->offset(); 1307 gold_assert(this->data_size() >= 24); 1308 unsigned char* const got_view = of->get_output_view(got_file_offset, 24); 1309 Output_section* dynamic = this->layout_->dynamic_section(); 1310 uint64_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); 1311 elfcpp::Swap<64, false>::writeval(got_view, dynamic_addr); 1312 memset(got_view + 8, 0, 16); 1313 of->write_output_view(got_file_offset, 24, got_view); 1314 } 1315 1316 // Initialize the PLT section. 1317 1318 template<int size> 1319 void 1320 Output_data_plt_x86_64<size>::init(Layout* layout) 1321 { 1322 this->rel_ = new Reloc_section(false); 1323 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1324 elfcpp::SHF_ALLOC, this->rel_, 1325 ORDER_DYNAMIC_PLT_RELOCS, false); 1326 } 1327 1328 template<int size> 1329 void 1330 Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os) 1331 { 1332 os->set_entsize(this->get_plt_entry_size()); 1333 } 1334 1335 // Add an entry to the PLT. 1336 1337 template<int size> 1338 void 1339 Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout, 1340 Symbol* gsym) 1341 { 1342 gold_assert(!gsym->has_plt_offset()); 1343 1344 unsigned int plt_index; 1345 off_t plt_offset; 1346 section_offset_type got_offset; 1347 1348 unsigned int* pcount; 1349 unsigned int offset; 1350 unsigned int reserved; 1351 Output_section_data_build* got; 1352 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1353 && gsym->can_use_relative_reloc(false)) 1354 { 1355 pcount = &this->irelative_count_; 1356 offset = 0; 1357 reserved = 0; 1358 got = this->got_irelative_; 1359 } 1360 else 1361 { 1362 pcount = &this->count_; 1363 offset = 1; 1364 reserved = 3; 1365 got = this->got_plt_; 1366 } 1367 1368 if (!this->is_data_size_valid()) 1369 { 1370 // Note that when setting the PLT offset for a non-IRELATIVE 1371 // entry we skip the initial reserved PLT entry. 1372 plt_index = *pcount + offset; 1373 plt_offset = plt_index * this->get_plt_entry_size(); 1374 1375 ++*pcount; 1376 1377 got_offset = (plt_index - offset + reserved) * 8; 1378 gold_assert(got_offset == got->current_data_size()); 1379 1380 // Every PLT entry needs a GOT entry which points back to the PLT 1381 // entry (this will be changed by the dynamic linker, normally 1382 // lazily when the function is called). 1383 got->set_current_data_size(got_offset + 8); 1384 } 1385 else 1386 { 1387 // FIXME: This is probably not correct for IRELATIVE relocs. 1388 1389 // For incremental updates, find an available slot. 1390 plt_offset = this->free_list_.allocate(this->get_plt_entry_size(), 1391 this->get_plt_entry_size(), 0); 1392 if (plt_offset == -1) 1393 gold_fallback(_("out of patch space (PLT);" 1394 " relink with --incremental-full")); 1395 1396 // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset 1397 // can be calculated from the PLT index, adjusting for the three 1398 // reserved entries at the beginning of the GOT. 1399 plt_index = plt_offset / this->get_plt_entry_size() - 1; 1400 got_offset = (plt_index - offset + reserved) * 8; 1401 } 1402 1403 gsym->set_plt_offset(plt_offset); 1404 1405 // Every PLT entry needs a reloc. 1406 this->add_relocation(symtab, layout, gsym, got_offset); 1407 1408 // Note that we don't need to save the symbol. The contents of the 1409 // PLT are independent of which symbols are used. The symbols only 1410 // appear in the relocations. 1411 } 1412 1413 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return 1414 // the PLT offset. 1415 1416 template<int size> 1417 unsigned int 1418 Output_data_plt_x86_64<size>::add_local_ifunc_entry( 1419 Symbol_table* symtab, 1420 Layout* layout, 1421 Sized_relobj_file<size, false>* relobj, 1422 unsigned int local_sym_index) 1423 { 1424 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); 1425 ++this->irelative_count_; 1426 1427 section_offset_type got_offset = this->got_irelative_->current_data_size(); 1428 1429 // Every PLT entry needs a GOT entry which points back to the PLT 1430 // entry. 1431 this->got_irelative_->set_current_data_size(got_offset + 8); 1432 1433 // Every PLT entry needs a reloc. 1434 Reloc_section* rela = this->rela_irelative(symtab, layout); 1435 rela->add_symbolless_local_addend(relobj, local_sym_index, 1436 elfcpp::R_X86_64_IRELATIVE, 1437 this->got_irelative_, got_offset, 0); 1438 1439 return plt_offset; 1440 } 1441 1442 // Add the relocation for a PLT entry. 1443 1444 template<int size> 1445 void 1446 Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab, 1447 Layout* layout, 1448 Symbol* gsym, 1449 unsigned int got_offset) 1450 { 1451 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1452 && gsym->can_use_relative_reloc(false)) 1453 { 1454 Reloc_section* rela = this->rela_irelative(symtab, layout); 1455 rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE, 1456 this->got_irelative_, got_offset, 0); 1457 } 1458 else 1459 { 1460 gsym->set_needs_dynsym_entry(); 1461 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, 1462 got_offset, 0); 1463 } 1464 } 1465 1466 // Return where the TLSDESC relocations should go, creating it if 1467 // necessary. These follow the JUMP_SLOT relocations. 1468 1469 template<int size> 1470 typename Output_data_plt_x86_64<size>::Reloc_section* 1471 Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout) 1472 { 1473 if (this->tlsdesc_rel_ == NULL) 1474 { 1475 this->tlsdesc_rel_ = new Reloc_section(false); 1476 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1477 elfcpp::SHF_ALLOC, this->tlsdesc_rel_, 1478 ORDER_DYNAMIC_PLT_RELOCS, false); 1479 gold_assert(this->tlsdesc_rel_->output_section() 1480 == this->rel_->output_section()); 1481 } 1482 return this->tlsdesc_rel_; 1483 } 1484 1485 // Return where the IRELATIVE relocations should go in the PLT. These 1486 // follow the JUMP_SLOT and the TLSDESC relocations. 1487 1488 template<int size> 1489 typename Output_data_plt_x86_64<size>::Reloc_section* 1490 Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab, 1491 Layout* layout) 1492 { 1493 if (this->irelative_rel_ == NULL) 1494 { 1495 // Make sure we have a place for the TLSDESC relocations, in 1496 // case we see any later on. 1497 this->rela_tlsdesc(layout); 1498 this->irelative_rel_ = new Reloc_section(false); 1499 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1500 elfcpp::SHF_ALLOC, this->irelative_rel_, 1501 ORDER_DYNAMIC_PLT_RELOCS, false); 1502 gold_assert(this->irelative_rel_->output_section() 1503 == this->rel_->output_section()); 1504 1505 if (parameters->doing_static_link()) 1506 { 1507 // A statically linked executable will only have a .rela.plt 1508 // section to hold R_X86_64_IRELATIVE relocs for 1509 // STT_GNU_IFUNC symbols. The library will use these 1510 // symbols to locate the IRELATIVE relocs at program startup 1511 // time. 1512 symtab->define_in_output_data("__rela_iplt_start", NULL, 1513 Symbol_table::PREDEFINED, 1514 this->irelative_rel_, 0, 0, 1515 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, 1516 elfcpp::STV_HIDDEN, 0, false, true); 1517 symtab->define_in_output_data("__rela_iplt_end", NULL, 1518 Symbol_table::PREDEFINED, 1519 this->irelative_rel_, 0, 0, 1520 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, 1521 elfcpp::STV_HIDDEN, 0, true, true); 1522 } 1523 } 1524 return this->irelative_rel_; 1525 } 1526 1527 // Return the PLT address to use for a global symbol. 1528 1529 template<int size> 1530 uint64_t 1531 Output_data_plt_x86_64<size>::address_for_global(const Symbol* gsym) 1532 { 1533 uint64_t offset = 0; 1534 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1535 && gsym->can_use_relative_reloc(false)) 1536 offset = (this->count_ + 1) * this->get_plt_entry_size(); 1537 return this->address() + offset + gsym->plt_offset(); 1538 } 1539 1540 // Return the PLT address to use for a local symbol. These are always 1541 // IRELATIVE relocs. 1542 1543 template<int size> 1544 uint64_t 1545 Output_data_plt_x86_64<size>::address_for_local(const Relobj* object, 1546 unsigned int r_sym) 1547 { 1548 return (this->address() 1549 + (this->count_ + 1) * this->get_plt_entry_size() 1550 + object->local_plt_offset(r_sym)); 1551 } 1552 1553 // Set the final size. 1554 template<int size> 1555 void 1556 Output_data_plt_x86_64<size>::set_final_data_size() 1557 { 1558 unsigned int count = this->count_ + this->irelative_count_; 1559 if (this->has_tlsdesc_entry()) 1560 ++count; 1561 this->set_data_size((count + 1) * this->get_plt_entry_size()); 1562 } 1563 1564 // The first entry in the PLT for an executable. 1565 1566 template<int size> 1567 const unsigned char 1568 Output_data_plt_x86_64_standard<size>::first_plt_entry[plt_entry_size] = 1569 { 1570 // From AMD64 ABI Draft 0.98, page 76 1571 0xff, 0x35, // pushq contents of memory address 1572 0, 0, 0, 0, // replaced with address of .got + 8 1573 0xff, 0x25, // jmp indirect 1574 0, 0, 0, 0, // replaced with address of .got + 16 1575 0x90, 0x90, 0x90, 0x90 // noop (x4) 1576 }; 1577 1578 template<int size> 1579 void 1580 Output_data_plt_x86_64_standard<size>::do_fill_first_plt_entry( 1581 unsigned char* pov, 1582 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1583 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 1584 { 1585 memcpy(pov, first_plt_entry, plt_entry_size); 1586 // We do a jmp relative to the PC at the end of this instruction. 1587 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1588 (got_address + 8 1589 - (plt_address + 6))); 1590 elfcpp::Swap<32, false>::writeval(pov + 8, 1591 (got_address + 16 1592 - (plt_address + 12))); 1593 } 1594 1595 // Subsequent entries in the PLT for an executable. 1596 1597 template<int size> 1598 const unsigned char 1599 Output_data_plt_x86_64_standard<size>::plt_entry[plt_entry_size] = 1600 { 1601 // From AMD64 ABI Draft 0.98, page 76 1602 0xff, 0x25, // jmpq indirect 1603 0, 0, 0, 0, // replaced with address of symbol in .got 1604 0x68, // pushq immediate 1605 0, 0, 0, 0, // replaced with offset into relocation table 1606 0xe9, // jmpq relative 1607 0, 0, 0, 0 // replaced with offset to start of .plt 1608 }; 1609 1610 template<int size> 1611 unsigned int 1612 Output_data_plt_x86_64_standard<size>::do_fill_plt_entry( 1613 unsigned char* pov, 1614 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1615 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 1616 unsigned int got_offset, 1617 unsigned int plt_offset, 1618 unsigned int plt_index) 1619 { 1620 // Check PC-relative offset overflow in PLT entry. 1621 uint64_t plt_got_pcrel_offset = (got_address + got_offset 1622 - (plt_address + plt_offset + 6)); 1623 if (Bits<32>::has_overflow(plt_got_pcrel_offset)) 1624 gold_error(_("PC-relative offset overflow in PLT entry %d"), 1625 plt_index + 1); 1626 1627 memcpy(pov, plt_entry, plt_entry_size); 1628 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1629 plt_got_pcrel_offset); 1630 1631 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index); 1632 elfcpp::Swap<32, false>::writeval(pov + 12, 1633 - (plt_offset + plt_entry_size)); 1634 1635 return 6; 1636 } 1637 1638 // The reserved TLSDESC entry in the PLT for an executable. 1639 1640 template<int size> 1641 const unsigned char 1642 Output_data_plt_x86_64_standard<size>::tlsdesc_plt_entry[plt_entry_size] = 1643 { 1644 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 1645 // and AMD64/EM64T", Version 0.9.4 (2005-10-10). 1646 0xff, 0x35, // pushq x(%rip) 1647 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) 1648 0xff, 0x25, // jmpq *y(%rip) 1649 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry 1650 0x0f, 0x1f, // nop 1651 0x40, 0 1652 }; 1653 1654 template<int size> 1655 void 1656 Output_data_plt_x86_64_standard<size>::do_fill_tlsdesc_entry( 1657 unsigned char* pov, 1658 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1659 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 1660 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 1661 unsigned int tlsdesc_got_offset, 1662 unsigned int plt_offset) 1663 { 1664 memcpy(pov, tlsdesc_plt_entry, plt_entry_size); 1665 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1666 (got_address + 8 1667 - (plt_address + plt_offset 1668 + 6))); 1669 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8, 1670 (got_base 1671 + tlsdesc_got_offset 1672 - (plt_address + plt_offset 1673 + 12))); 1674 } 1675 1676 // The .eh_frame unwind information for the PLT. 1677 1678 template<int size> 1679 const unsigned char 1680 Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] = 1681 { 1682 1, // CIE version. 1683 'z', // Augmentation: augmentation size included. 1684 'R', // Augmentation: FDE encoding included. 1685 '\0', // End of augmentation string. 1686 1, // Code alignment factor. 1687 0x78, // Data alignment factor. 1688 16, // Return address column. 1689 1, // Augmentation size. 1690 (elfcpp::DW_EH_PE_pcrel // FDE encoding. 1691 | elfcpp::DW_EH_PE_sdata4), 1692 elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8. 1693 elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8. 1694 elfcpp::DW_CFA_nop, // Align to 16 bytes. 1695 elfcpp::DW_CFA_nop 1696 }; 1697 1698 template<int size> 1699 const unsigned char 1700 Output_data_plt_x86_64_standard<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = 1701 { 1702 0, 0, 0, 0, // Replaced with offset to .plt. 1703 0, 0, 0, 0, // Replaced with size of .plt. 1704 0, // Augmentation size. 1705 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. 1706 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. 1707 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. 1708 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. 1709 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. 1710 11, // Block length. 1711 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. 1712 elfcpp::DW_OP_breg16, 0, // Push %rip. 1713 elfcpp::DW_OP_lit15, // Push 0xf. 1714 elfcpp::DW_OP_and, // & (%rip & 0xf). 1715 elfcpp::DW_OP_lit11, // Push 0xb. 1716 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb) 1717 elfcpp::DW_OP_lit3, // Push 3. 1718 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3) 1719 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8 1720 elfcpp::DW_CFA_nop, // Align to 32 bytes. 1721 elfcpp::DW_CFA_nop, 1722 elfcpp::DW_CFA_nop, 1723 elfcpp::DW_CFA_nop 1724 }; 1725 1726 // Write out the PLT. This uses the hand-coded instructions above, 1727 // and adjusts them as needed. This is specified by the AMD64 ABI. 1728 1729 template<int size> 1730 void 1731 Output_data_plt_x86_64<size>::do_write(Output_file* of) 1732 { 1733 const off_t offset = this->offset(); 1734 const section_size_type oview_size = 1735 convert_to_section_size_type(this->data_size()); 1736 unsigned char* const oview = of->get_output_view(offset, oview_size); 1737 1738 const off_t got_file_offset = this->got_plt_->offset(); 1739 gold_assert(parameters->incremental_update() 1740 || (got_file_offset + this->got_plt_->data_size() 1741 == this->got_irelative_->offset())); 1742 const section_size_type got_size = 1743 convert_to_section_size_type(this->got_plt_->data_size() 1744 + this->got_irelative_->data_size()); 1745 unsigned char* const got_view = of->get_output_view(got_file_offset, 1746 got_size); 1747 1748 unsigned char* pov = oview; 1749 1750 // The base address of the .plt section. 1751 typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address(); 1752 // The base address of the .got section. 1753 typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address(); 1754 // The base address of the PLT portion of the .got section, 1755 // which is where the GOT pointer will point, and where the 1756 // three reserved GOT entries are located. 1757 typename elfcpp::Elf_types<size>::Elf_Addr got_address 1758 = this->got_plt_->address(); 1759 1760 this->fill_first_plt_entry(pov, got_address, plt_address); 1761 pov += this->get_plt_entry_size(); 1762 1763 // The first three entries in the GOT are reserved, and are written 1764 // by Output_data_got_plt_x86_64::do_write. 1765 unsigned char* got_pov = got_view + 24; 1766 1767 unsigned int plt_offset = this->get_plt_entry_size(); 1768 unsigned int got_offset = 24; 1769 const unsigned int count = this->count_ + this->irelative_count_; 1770 for (unsigned int plt_index = 0; 1771 plt_index < count; 1772 ++plt_index, 1773 pov += this->get_plt_entry_size(), 1774 got_pov += 8, 1775 plt_offset += this->get_plt_entry_size(), 1776 got_offset += 8) 1777 { 1778 // Set and adjust the PLT entry itself. 1779 unsigned int lazy_offset = this->fill_plt_entry(pov, 1780 got_address, plt_address, 1781 got_offset, plt_offset, 1782 plt_index); 1783 1784 // Set the entry in the GOT. 1785 elfcpp::Swap<64, false>::writeval(got_pov, 1786 plt_address + plt_offset + lazy_offset); 1787 } 1788 1789 if (this->has_tlsdesc_entry()) 1790 { 1791 // Set and adjust the reserved TLSDESC PLT entry. 1792 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); 1793 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base, 1794 tlsdesc_got_offset, plt_offset); 1795 pov += this->get_plt_entry_size(); 1796 } 1797 1798 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); 1799 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); 1800 1801 of->write_output_view(offset, oview_size, oview); 1802 of->write_output_view(got_file_offset, got_size, got_view); 1803 } 1804 1805 // Create the PLT section. 1806 1807 template<int size> 1808 void 1809 Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout) 1810 { 1811 if (this->plt_ == NULL) 1812 { 1813 // Create the GOT sections first. 1814 this->got_section(symtab, layout); 1815 1816 this->plt_ = this->make_data_plt(layout, this->got_, this->got_plt_, 1817 this->got_irelative_); 1818 1819 // Add unwind information if requested. 1820 if (parameters->options().ld_generated_unwind_info()) 1821 this->plt_->add_eh_frame(layout); 1822 1823 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, 1824 (elfcpp::SHF_ALLOC 1825 | elfcpp::SHF_EXECINSTR), 1826 this->plt_, ORDER_PLT, false); 1827 1828 // Make the sh_info field of .rela.plt point to .plt. 1829 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); 1830 rela_plt_os->set_info_section(this->plt_->output_section()); 1831 } 1832 } 1833 1834 // Return the section for TLSDESC relocations. 1835 1836 template<int size> 1837 typename Target_x86_64<size>::Reloc_section* 1838 Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const 1839 { 1840 return this->plt_section()->rela_tlsdesc(layout); 1841 } 1842 1843 // Create a PLT entry for a global symbol. 1844 1845 template<int size> 1846 void 1847 Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout, 1848 Symbol* gsym) 1849 { 1850 if (gsym->has_plt_offset()) 1851 return; 1852 1853 if (this->plt_ == NULL) 1854 this->make_plt_section(symtab, layout); 1855 1856 this->plt_->add_entry(symtab, layout, gsym); 1857 } 1858 1859 // Make a PLT entry for a local STT_GNU_IFUNC symbol. 1860 1861 template<int size> 1862 void 1863 Target_x86_64<size>::make_local_ifunc_plt_entry( 1864 Symbol_table* symtab, Layout* layout, 1865 Sized_relobj_file<size, false>* relobj, 1866 unsigned int local_sym_index) 1867 { 1868 if (relobj->local_has_plt_offset(local_sym_index)) 1869 return; 1870 if (this->plt_ == NULL) 1871 this->make_plt_section(symtab, layout); 1872 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, 1873 relobj, 1874 local_sym_index); 1875 relobj->set_local_plt_offset(local_sym_index, plt_offset); 1876 } 1877 1878 // Return the number of entries in the PLT. 1879 1880 template<int size> 1881 unsigned int 1882 Target_x86_64<size>::plt_entry_count() const 1883 { 1884 if (this->plt_ == NULL) 1885 return 0; 1886 return this->plt_->entry_count(); 1887 } 1888 1889 // Return the offset of the first non-reserved PLT entry. 1890 1891 template<int size> 1892 unsigned int 1893 Target_x86_64<size>::first_plt_entry_offset() const 1894 { 1895 if (this->plt_ == NULL) 1896 return 0; 1897 return this->plt_->first_plt_entry_offset(); 1898 } 1899 1900 // Return the size of each PLT entry. 1901 1902 template<int size> 1903 unsigned int 1904 Target_x86_64<size>::plt_entry_size() const 1905 { 1906 if (this->plt_ == NULL) 1907 return 0; 1908 return this->plt_->get_plt_entry_size(); 1909 } 1910 1911 // Create the GOT and PLT sections for an incremental update. 1912 1913 template<int size> 1914 Output_data_got_base* 1915 Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab, 1916 Layout* layout, 1917 unsigned int got_count, 1918 unsigned int plt_count) 1919 { 1920 gold_assert(this->got_ == NULL); 1921 1922 this->got_ = new Output_data_got<64, false>(got_count * 8); 1923 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, 1924 (elfcpp::SHF_ALLOC 1925 | elfcpp::SHF_WRITE), 1926 this->got_, ORDER_RELRO_LAST, 1927 true); 1928 1929 // Add the three reserved entries. 1930 this->got_plt_ = new Output_data_got_plt_x86_64(layout, (plt_count + 3) * 8); 1931 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1932 (elfcpp::SHF_ALLOC 1933 | elfcpp::SHF_WRITE), 1934 this->got_plt_, ORDER_NON_RELRO_FIRST, 1935 false); 1936 1937 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. 1938 this->global_offset_table_ = 1939 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, 1940 Symbol_table::PREDEFINED, 1941 this->got_plt_, 1942 0, 0, elfcpp::STT_OBJECT, 1943 elfcpp::STB_LOCAL, 1944 elfcpp::STV_HIDDEN, 0, 1945 false, false); 1946 1947 // If there are any TLSDESC relocations, they get GOT entries in 1948 // .got.plt after the jump slot entries. 1949 // FIXME: Get the count for TLSDESC entries. 1950 this->got_tlsdesc_ = new Output_data_got<64, false>(0); 1951 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1952 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, 1953 this->got_tlsdesc_, 1954 ORDER_NON_RELRO_FIRST, false); 1955 1956 // If there are any IRELATIVE relocations, they get GOT entries in 1957 // .got.plt after the jump slot and TLSDESC entries. 1958 this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT"); 1959 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1960 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, 1961 this->got_irelative_, 1962 ORDER_NON_RELRO_FIRST, false); 1963 1964 // Create the PLT section. 1965 this->plt_ = this->make_data_plt(layout, this->got_, 1966 this->got_plt_, 1967 this->got_irelative_, 1968 plt_count); 1969 1970 // Add unwind information if requested. 1971 if (parameters->options().ld_generated_unwind_info()) 1972 this->plt_->add_eh_frame(layout); 1973 1974 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, 1975 elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR, 1976 this->plt_, ORDER_PLT, false); 1977 1978 // Make the sh_info field of .rela.plt point to .plt. 1979 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); 1980 rela_plt_os->set_info_section(this->plt_->output_section()); 1981 1982 // Create the rela_dyn section. 1983 this->rela_dyn_section(layout); 1984 1985 return this->got_; 1986 } 1987 1988 // Reserve a GOT entry for a local symbol, and regenerate any 1989 // necessary dynamic relocations. 1990 1991 template<int size> 1992 void 1993 Target_x86_64<size>::reserve_local_got_entry( 1994 unsigned int got_index, 1995 Sized_relobj<size, false>* obj, 1996 unsigned int r_sym, 1997 unsigned int got_type) 1998 { 1999 unsigned int got_offset = got_index * 8; 2000 Reloc_section* rela_dyn = this->rela_dyn_section(NULL); 2001 2002 this->got_->reserve_local(got_index, obj, r_sym, got_type); 2003 switch (got_type) 2004 { 2005 case GOT_TYPE_STANDARD: 2006 if (parameters->options().output_is_position_independent()) 2007 rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE, 2008 this->got_, got_offset, 0, false); 2009 break; 2010 case GOT_TYPE_TLS_OFFSET: 2011 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64, 2012 this->got_, got_offset, 0); 2013 break; 2014 case GOT_TYPE_TLS_PAIR: 2015 this->got_->reserve_slot(got_index + 1); 2016 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64, 2017 this->got_, got_offset, 0); 2018 break; 2019 case GOT_TYPE_TLS_DESC: 2020 gold_fatal(_("TLS_DESC not yet supported for incremental linking")); 2021 // this->got_->reserve_slot(got_index + 1); 2022 // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, 2023 // this->got_, got_offset, 0); 2024 break; 2025 default: 2026 gold_unreachable(); 2027 } 2028 } 2029 2030 // Reserve a GOT entry for a global symbol, and regenerate any 2031 // necessary dynamic relocations. 2032 2033 template<int size> 2034 void 2035 Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index, 2036 Symbol* gsym, 2037 unsigned int got_type) 2038 { 2039 unsigned int got_offset = got_index * 8; 2040 Reloc_section* rela_dyn = this->rela_dyn_section(NULL); 2041 2042 this->got_->reserve_global(got_index, gsym, got_type); 2043 switch (got_type) 2044 { 2045 case GOT_TYPE_STANDARD: 2046 if (!gsym->final_value_is_known()) 2047 { 2048 if (gsym->is_from_dynobj() 2049 || gsym->is_undefined() 2050 || gsym->is_preemptible() 2051 || gsym->type() == elfcpp::STT_GNU_IFUNC) 2052 rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT, 2053 this->got_, got_offset, 0); 2054 else 2055 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, 2056 this->got_, got_offset, 0, false); 2057 } 2058 break; 2059 case GOT_TYPE_TLS_OFFSET: 2060 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64, 2061 this->got_, got_offset, 0, false); 2062 break; 2063 case GOT_TYPE_TLS_PAIR: 2064 this->got_->reserve_slot(got_index + 1); 2065 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64, 2066 this->got_, got_offset, 0, false); 2067 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64, 2068 this->got_, got_offset + 8, 0, false); 2069 break; 2070 case GOT_TYPE_TLS_DESC: 2071 this->got_->reserve_slot(got_index + 1); 2072 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC, 2073 this->got_, got_offset, 0, false); 2074 break; 2075 default: 2076 gold_unreachable(); 2077 } 2078 } 2079 2080 // Register an existing PLT entry for a global symbol. 2081 2082 template<int size> 2083 void 2084 Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab, 2085 Layout* layout, 2086 unsigned int plt_index, 2087 Symbol* gsym) 2088 { 2089 gold_assert(this->plt_ != NULL); 2090 gold_assert(!gsym->has_plt_offset()); 2091 2092 this->plt_->reserve_slot(plt_index); 2093 2094 gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size()); 2095 2096 unsigned int got_offset = (plt_index + 3) * 8; 2097 this->plt_->add_relocation(symtab, layout, gsym, got_offset); 2098 } 2099 2100 // Force a COPY relocation for a given symbol. 2101 2102 template<int size> 2103 void 2104 Target_x86_64<size>::emit_copy_reloc( 2105 Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset) 2106 { 2107 this->copy_relocs_.emit_copy_reloc(symtab, 2108 symtab->get_sized_symbol<size>(sym), 2109 os, 2110 offset, 2111 this->rela_dyn_section(NULL)); 2112 } 2113 2114 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. 2115 2116 template<int size> 2117 void 2118 Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab, 2119 Layout* layout) 2120 { 2121 if (this->tls_base_symbol_defined_) 2122 return; 2123 2124 Output_segment* tls_segment = layout->tls_segment(); 2125 if (tls_segment != NULL) 2126 { 2127 bool is_exec = parameters->options().output_is_executable(); 2128 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, 2129 Symbol_table::PREDEFINED, 2130 tls_segment, 0, 0, 2131 elfcpp::STT_TLS, 2132 elfcpp::STB_LOCAL, 2133 elfcpp::STV_HIDDEN, 0, 2134 (is_exec 2135 ? Symbol::SEGMENT_END 2136 : Symbol::SEGMENT_START), 2137 true); 2138 } 2139 this->tls_base_symbol_defined_ = true; 2140 } 2141 2142 // Create the reserved PLT and GOT entries for the TLS descriptor resolver. 2143 2144 template<int size> 2145 void 2146 Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab, 2147 Layout* layout) 2148 { 2149 if (this->plt_ == NULL) 2150 this->make_plt_section(symtab, layout); 2151 2152 if (!this->plt_->has_tlsdesc_entry()) 2153 { 2154 // Allocate the TLSDESC_GOT entry. 2155 Output_data_got<64, false>* got = this->got_section(symtab, layout); 2156 unsigned int got_offset = got->add_constant(0); 2157 2158 // Allocate the TLSDESC_PLT entry. 2159 this->plt_->reserve_tlsdesc_entry(got_offset); 2160 } 2161 } 2162 2163 // Create a GOT entry for the TLS module index. 2164 2165 template<int size> 2166 unsigned int 2167 Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout, 2168 Sized_relobj_file<size, false>* object) 2169 { 2170 if (this->got_mod_index_offset_ == -1U) 2171 { 2172 gold_assert(symtab != NULL && layout != NULL && object != NULL); 2173 Reloc_section* rela_dyn = this->rela_dyn_section(layout); 2174 Output_data_got<64, false>* got = this->got_section(symtab, layout); 2175 unsigned int got_offset = got->add_constant(0); 2176 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got, 2177 got_offset, 0); 2178 got->add_constant(0); 2179 this->got_mod_index_offset_ = got_offset; 2180 } 2181 return this->got_mod_index_offset_; 2182 } 2183 2184 // Optimize the TLS relocation type based on what we know about the 2185 // symbol. IS_FINAL is true if the final address of this symbol is 2186 // known at link time. 2187 2188 template<int size> 2189 tls::Tls_optimization 2190 Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type) 2191 { 2192 // If we are generating a shared library, then we can't do anything 2193 // in the linker. 2194 if (parameters->options().shared()) 2195 return tls::TLSOPT_NONE; 2196 2197 switch (r_type) 2198 { 2199 case elfcpp::R_X86_64_TLSGD: 2200 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 2201 case elfcpp::R_X86_64_TLSDESC_CALL: 2202 // These are General-Dynamic which permits fully general TLS 2203 // access. Since we know that we are generating an executable, 2204 // we can convert this to Initial-Exec. If we also know that 2205 // this is a local symbol, we can further switch to Local-Exec. 2206 if (is_final) 2207 return tls::TLSOPT_TO_LE; 2208 return tls::TLSOPT_TO_IE; 2209 2210 case elfcpp::R_X86_64_TLSLD: 2211 // This is Local-Dynamic, which refers to a local symbol in the 2212 // dynamic TLS block. Since we know that we generating an 2213 // executable, we can switch to Local-Exec. 2214 return tls::TLSOPT_TO_LE; 2215 2216 case elfcpp::R_X86_64_DTPOFF32: 2217 case elfcpp::R_X86_64_DTPOFF64: 2218 // Another Local-Dynamic reloc. 2219 return tls::TLSOPT_TO_LE; 2220 2221 case elfcpp::R_X86_64_GOTTPOFF: 2222 // These are Initial-Exec relocs which get the thread offset 2223 // from the GOT. If we know that we are linking against the 2224 // local symbol, we can switch to Local-Exec, which links the 2225 // thread offset into the instruction. 2226 if (is_final) 2227 return tls::TLSOPT_TO_LE; 2228 return tls::TLSOPT_NONE; 2229 2230 case elfcpp::R_X86_64_TPOFF32: 2231 // When we already have Local-Exec, there is nothing further we 2232 // can do. 2233 return tls::TLSOPT_NONE; 2234 2235 default: 2236 gold_unreachable(); 2237 } 2238 } 2239 2240 // Get the Reference_flags for a particular relocation. 2241 2242 template<int size> 2243 int 2244 Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type) 2245 { 2246 switch (r_type) 2247 { 2248 case elfcpp::R_X86_64_NONE: 2249 case elfcpp::R_X86_64_GNU_VTINHERIT: 2250 case elfcpp::R_X86_64_GNU_VTENTRY: 2251 case elfcpp::R_X86_64_GOTPC32: 2252 case elfcpp::R_X86_64_GOTPC64: 2253 // No symbol reference. 2254 return 0; 2255 2256 case elfcpp::R_X86_64_64: 2257 case elfcpp::R_X86_64_32: 2258 case elfcpp::R_X86_64_32S: 2259 case elfcpp::R_X86_64_16: 2260 case elfcpp::R_X86_64_8: 2261 return Symbol::ABSOLUTE_REF; 2262 2263 case elfcpp::R_X86_64_PC64: 2264 case elfcpp::R_X86_64_PC32: 2265 case elfcpp::R_X86_64_PC32_BND: 2266 case elfcpp::R_X86_64_PC16: 2267 case elfcpp::R_X86_64_PC8: 2268 case elfcpp::R_X86_64_GOTOFF64: 2269 return Symbol::RELATIVE_REF; 2270 2271 case elfcpp::R_X86_64_PLT32: 2272 case elfcpp::R_X86_64_PLT32_BND: 2273 case elfcpp::R_X86_64_PLTOFF64: 2274 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; 2275 2276 case elfcpp::R_X86_64_GOT64: 2277 case elfcpp::R_X86_64_GOT32: 2278 case elfcpp::R_X86_64_GOTPCREL64: 2279 case elfcpp::R_X86_64_GOTPCREL: 2280 case elfcpp::R_X86_64_GOTPCRELX: 2281 case elfcpp::R_X86_64_REX_GOTPCRELX: 2282 case elfcpp::R_X86_64_GOTPLT64: 2283 // Absolute in GOT. 2284 return Symbol::ABSOLUTE_REF; 2285 2286 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 2287 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 2288 case elfcpp::R_X86_64_TLSDESC_CALL: 2289 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 2290 case elfcpp::R_X86_64_DTPOFF32: 2291 case elfcpp::R_X86_64_DTPOFF64: 2292 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 2293 case elfcpp::R_X86_64_TPOFF32: // Local-exec 2294 return Symbol::TLS_REF; 2295 2296 case elfcpp::R_X86_64_COPY: 2297 case elfcpp::R_X86_64_GLOB_DAT: 2298 case elfcpp::R_X86_64_JUMP_SLOT: 2299 case elfcpp::R_X86_64_RELATIVE: 2300 case elfcpp::R_X86_64_IRELATIVE: 2301 case elfcpp::R_X86_64_TPOFF64: 2302 case elfcpp::R_X86_64_DTPMOD64: 2303 case elfcpp::R_X86_64_TLSDESC: 2304 case elfcpp::R_X86_64_SIZE32: 2305 case elfcpp::R_X86_64_SIZE64: 2306 default: 2307 // Not expected. We will give an error later. 2308 return 0; 2309 } 2310 } 2311 2312 // Report an unsupported relocation against a local symbol. 2313 2314 template<int size> 2315 void 2316 Target_x86_64<size>::Scan::unsupported_reloc_local( 2317 Sized_relobj_file<size, false>* object, 2318 unsigned int r_type) 2319 { 2320 gold_error(_("%s: unsupported reloc %u against local symbol"), 2321 object->name().c_str(), r_type); 2322 } 2323 2324 // We are about to emit a dynamic relocation of type R_TYPE. If the 2325 // dynamic linker does not support it, issue an error. The GNU linker 2326 // only issues a non-PIC error for an allocated read-only section. 2327 // Here we know the section is allocated, but we don't know that it is 2328 // read-only. But we check for all the relocation types which the 2329 // glibc dynamic linker supports, so it seems appropriate to issue an 2330 // error even if the section is not read-only. If GSYM is not NULL, 2331 // it is the symbol the relocation is against; if it is NULL, the 2332 // relocation is against a local symbol. 2333 2334 template<int size> 2335 void 2336 Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type, 2337 Symbol* gsym) 2338 { 2339 switch (r_type) 2340 { 2341 // These are the relocation types supported by glibc for x86_64 2342 // which should always work. 2343 case elfcpp::R_X86_64_RELATIVE: 2344 case elfcpp::R_X86_64_IRELATIVE: 2345 case elfcpp::R_X86_64_GLOB_DAT: 2346 case elfcpp::R_X86_64_JUMP_SLOT: 2347 case elfcpp::R_X86_64_DTPMOD64: 2348 case elfcpp::R_X86_64_DTPOFF64: 2349 case elfcpp::R_X86_64_TPOFF64: 2350 case elfcpp::R_X86_64_64: 2351 case elfcpp::R_X86_64_COPY: 2352 return; 2353 2354 // glibc supports these reloc types, but they can overflow. 2355 case elfcpp::R_X86_64_PC32: 2356 case elfcpp::R_X86_64_PC32_BND: 2357 // A PC relative reference is OK against a local symbol or if 2358 // the symbol is defined locally. 2359 if (gsym == NULL 2360 || (!gsym->is_from_dynobj() 2361 && !gsym->is_undefined() 2362 && !gsym->is_preemptible())) 2363 return; 2364 /* Fall through. */ 2365 case elfcpp::R_X86_64_32: 2366 // R_X86_64_32 is OK for x32. 2367 if (size == 32 && r_type == elfcpp::R_X86_64_32) 2368 return; 2369 if (this->issued_non_pic_error_) 2370 return; 2371 gold_assert(parameters->options().output_is_position_independent()); 2372 if (gsym == NULL) 2373 object->error(_("requires dynamic R_X86_64_32 reloc which may " 2374 "overflow at runtime; recompile with -fPIC")); 2375 else 2376 { 2377 const char *r_name; 2378 switch (r_type) 2379 { 2380 case elfcpp::R_X86_64_32: 2381 r_name = "R_X86_64_32"; 2382 break; 2383 case elfcpp::R_X86_64_PC32: 2384 r_name = "R_X86_64_PC32"; 2385 break; 2386 case elfcpp::R_X86_64_PC32_BND: 2387 r_name = "R_X86_64_PC32_BND"; 2388 break; 2389 default: 2390 gold_unreachable(); 2391 break; 2392 } 2393 object->error(_("requires dynamic %s reloc against '%s' " 2394 "which may overflow at runtime; recompile " 2395 "with -fPIC"), 2396 r_name, gsym->name()); 2397 } 2398 this->issued_non_pic_error_ = true; 2399 return; 2400 2401 default: 2402 // This prevents us from issuing more than one error per reloc 2403 // section. But we can still wind up issuing more than one 2404 // error per object file. 2405 if (this->issued_non_pic_error_) 2406 return; 2407 gold_assert(parameters->options().output_is_position_independent()); 2408 object->error(_("requires unsupported dynamic reloc %u; " 2409 "recompile with -fPIC"), 2410 r_type); 2411 this->issued_non_pic_error_ = true; 2412 return; 2413 2414 case elfcpp::R_X86_64_NONE: 2415 gold_unreachable(); 2416 } 2417 } 2418 2419 // Return whether we need to make a PLT entry for a relocation of the 2420 // given type against a STT_GNU_IFUNC symbol. 2421 2422 template<int size> 2423 bool 2424 Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc( 2425 Sized_relobj_file<size, false>* object, 2426 unsigned int r_type) 2427 { 2428 int flags = Scan::get_reference_flags(r_type); 2429 if (flags & Symbol::TLS_REF) 2430 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), 2431 object->name().c_str(), r_type); 2432 return flags != 0; 2433 } 2434 2435 // Scan a relocation for a local symbol. 2436 2437 template<int size> 2438 inline void 2439 Target_x86_64<size>::Scan::local(Symbol_table* symtab, 2440 Layout* layout, 2441 Target_x86_64<size>* target, 2442 Sized_relobj_file<size, false>* object, 2443 unsigned int data_shndx, 2444 Output_section* output_section, 2445 const elfcpp::Rela<size, false>& reloc, 2446 unsigned int r_type, 2447 const elfcpp::Sym<size, false>& lsym, 2448 bool is_discarded) 2449 { 2450 if (is_discarded) 2451 return; 2452 2453 // A local STT_GNU_IFUNC symbol may require a PLT entry. 2454 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC; 2455 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type)) 2456 { 2457 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2458 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); 2459 } 2460 2461 switch (r_type) 2462 { 2463 case elfcpp::R_X86_64_NONE: 2464 case elfcpp::R_X86_64_GNU_VTINHERIT: 2465 case elfcpp::R_X86_64_GNU_VTENTRY: 2466 break; 2467 2468 case elfcpp::R_X86_64_64: 2469 // If building a shared library (or a position-independent 2470 // executable), we need to create a dynamic relocation for this 2471 // location. The relocation applied at link time will apply the 2472 // link-time value, so we flag the location with an 2473 // R_X86_64_RELATIVE relocation so the dynamic loader can 2474 // relocate it easily. 2475 if (parameters->options().output_is_position_independent()) 2476 { 2477 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2478 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2479 rela_dyn->add_local_relative(object, r_sym, 2480 (size == 32 2481 ? elfcpp::R_X86_64_RELATIVE64 2482 : elfcpp::R_X86_64_RELATIVE), 2483 output_section, data_shndx, 2484 reloc.get_r_offset(), 2485 reloc.get_r_addend(), is_ifunc); 2486 } 2487 break; 2488 2489 case elfcpp::R_X86_64_32: 2490 case elfcpp::R_X86_64_32S: 2491 case elfcpp::R_X86_64_16: 2492 case elfcpp::R_X86_64_8: 2493 // If building a shared library (or a position-independent 2494 // executable), we need to create a dynamic relocation for this 2495 // location. We can't use an R_X86_64_RELATIVE relocation 2496 // because that is always a 64-bit relocation. 2497 if (parameters->options().output_is_position_independent()) 2498 { 2499 // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32. 2500 if (size == 32 && r_type == elfcpp::R_X86_64_32) 2501 { 2502 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2503 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2504 rela_dyn->add_local_relative(object, r_sym, 2505 elfcpp::R_X86_64_RELATIVE, 2506 output_section, data_shndx, 2507 reloc.get_r_offset(), 2508 reloc.get_r_addend(), is_ifunc); 2509 break; 2510 } 2511 2512 this->check_non_pic(object, r_type, NULL); 2513 2514 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2515 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2516 if (lsym.get_st_type() != elfcpp::STT_SECTION) 2517 rela_dyn->add_local(object, r_sym, r_type, output_section, 2518 data_shndx, reloc.get_r_offset(), 2519 reloc.get_r_addend()); 2520 else 2521 { 2522 gold_assert(lsym.get_st_value() == 0); 2523 unsigned int shndx = lsym.get_st_shndx(); 2524 bool is_ordinary; 2525 shndx = object->adjust_sym_shndx(r_sym, shndx, 2526 &is_ordinary); 2527 if (!is_ordinary) 2528 object->error(_("section symbol %u has bad shndx %u"), 2529 r_sym, shndx); 2530 else 2531 rela_dyn->add_local_section(object, shndx, 2532 r_type, output_section, 2533 data_shndx, reloc.get_r_offset(), 2534 reloc.get_r_addend()); 2535 } 2536 } 2537 break; 2538 2539 case elfcpp::R_X86_64_PC64: 2540 case elfcpp::R_X86_64_PC32: 2541 case elfcpp::R_X86_64_PC32_BND: 2542 case elfcpp::R_X86_64_PC16: 2543 case elfcpp::R_X86_64_PC8: 2544 break; 2545 2546 case elfcpp::R_X86_64_PLT32: 2547 case elfcpp::R_X86_64_PLT32_BND: 2548 // Since we know this is a local symbol, we can handle this as a 2549 // PC32 reloc. 2550 break; 2551 2552 case elfcpp::R_X86_64_GOTPC32: 2553 case elfcpp::R_X86_64_GOTOFF64: 2554 case elfcpp::R_X86_64_GOTPC64: 2555 case elfcpp::R_X86_64_PLTOFF64: 2556 // We need a GOT section. 2557 target->got_section(symtab, layout); 2558 // For PLTOFF64, we'd normally want a PLT section, but since we 2559 // know this is a local symbol, no PLT is needed. 2560 break; 2561 2562 case elfcpp::R_X86_64_GOT64: 2563 case elfcpp::R_X86_64_GOT32: 2564 case elfcpp::R_X86_64_GOTPCREL64: 2565 case elfcpp::R_X86_64_GOTPCREL: 2566 case elfcpp::R_X86_64_GOTPCRELX: 2567 case elfcpp::R_X86_64_REX_GOTPCRELX: 2568 case elfcpp::R_X86_64_GOTPLT64: 2569 { 2570 // The symbol requires a GOT section. 2571 Output_data_got<64, false>* got = target->got_section(symtab, layout); 2572 2573 // If the relocation symbol isn't IFUNC, 2574 // and is local, then we will convert 2575 // mov foo@GOTPCREL(%rip), %reg 2576 // to lea foo(%rip), %reg. 2577 // in Relocate::relocate. 2578 if ((r_type == elfcpp::R_X86_64_GOTPCREL 2579 || r_type == elfcpp::R_X86_64_GOTPCRELX 2580 || r_type == elfcpp::R_X86_64_REX_GOTPCRELX) 2581 && reloc.get_r_offset() >= 2 2582 && !is_ifunc) 2583 { 2584 section_size_type stype; 2585 const unsigned char* view = object->section_contents(data_shndx, 2586 &stype, true); 2587 if (view[reloc.get_r_offset() - 2] == 0x8b) 2588 break; 2589 } 2590 2591 2592 // The symbol requires a GOT entry. 2593 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2594 2595 // For a STT_GNU_IFUNC symbol we want the PLT offset. That 2596 // lets function pointers compare correctly with shared 2597 // libraries. Otherwise we would need an IRELATIVE reloc. 2598 bool is_new; 2599 if (is_ifunc) 2600 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); 2601 else 2602 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); 2603 if (is_new) 2604 { 2605 // If we are generating a shared object, we need to add a 2606 // dynamic relocation for this symbol's GOT entry. 2607 if (parameters->options().output_is_position_independent()) 2608 { 2609 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2610 // R_X86_64_RELATIVE assumes a 64-bit relocation. 2611 if (r_type != elfcpp::R_X86_64_GOT32) 2612 { 2613 unsigned int got_offset = 2614 object->local_got_offset(r_sym, GOT_TYPE_STANDARD); 2615 rela_dyn->add_local_relative(object, r_sym, 2616 elfcpp::R_X86_64_RELATIVE, 2617 got, got_offset, 0, is_ifunc); 2618 } 2619 else 2620 { 2621 this->check_non_pic(object, r_type, NULL); 2622 2623 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); 2624 rela_dyn->add_local( 2625 object, r_sym, r_type, got, 2626 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0); 2627 } 2628 } 2629 } 2630 // For GOTPLT64, we'd normally want a PLT section, but since 2631 // we know this is a local symbol, no PLT is needed. 2632 } 2633 break; 2634 2635 case elfcpp::R_X86_64_COPY: 2636 case elfcpp::R_X86_64_GLOB_DAT: 2637 case elfcpp::R_X86_64_JUMP_SLOT: 2638 case elfcpp::R_X86_64_RELATIVE: 2639 case elfcpp::R_X86_64_IRELATIVE: 2640 // These are outstanding tls relocs, which are unexpected when linking 2641 case elfcpp::R_X86_64_TPOFF64: 2642 case elfcpp::R_X86_64_DTPMOD64: 2643 case elfcpp::R_X86_64_TLSDESC: 2644 gold_error(_("%s: unexpected reloc %u in object file"), 2645 object->name().c_str(), r_type); 2646 break; 2647 2648 // These are initial tls relocs, which are expected when linking 2649 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 2650 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 2651 case elfcpp::R_X86_64_TLSDESC_CALL: 2652 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 2653 case elfcpp::R_X86_64_DTPOFF32: 2654 case elfcpp::R_X86_64_DTPOFF64: 2655 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 2656 case elfcpp::R_X86_64_TPOFF32: // Local-exec 2657 { 2658 bool output_is_shared = parameters->options().shared(); 2659 const tls::Tls_optimization optimized_type 2660 = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared, 2661 r_type); 2662 switch (r_type) 2663 { 2664 case elfcpp::R_X86_64_TLSGD: // General-dynamic 2665 if (optimized_type == tls::TLSOPT_NONE) 2666 { 2667 // Create a pair of GOT entries for the module index and 2668 // dtv-relative offset. 2669 Output_data_got<64, false>* got 2670 = target->got_section(symtab, layout); 2671 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2672 unsigned int shndx = lsym.get_st_shndx(); 2673 bool is_ordinary; 2674 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); 2675 if (!is_ordinary) 2676 object->error(_("local symbol %u has bad shndx %u"), 2677 r_sym, shndx); 2678 else 2679 got->add_local_pair_with_rel(object, r_sym, 2680 shndx, 2681 GOT_TYPE_TLS_PAIR, 2682 target->rela_dyn_section(layout), 2683 elfcpp::R_X86_64_DTPMOD64); 2684 } 2685 else if (optimized_type != tls::TLSOPT_TO_LE) 2686 unsupported_reloc_local(object, r_type); 2687 break; 2688 2689 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 2690 target->define_tls_base_symbol(symtab, layout); 2691 if (optimized_type == tls::TLSOPT_NONE) 2692 { 2693 // Create reserved PLT and GOT entries for the resolver. 2694 target->reserve_tlsdesc_entries(symtab, layout); 2695 2696 // Generate a double GOT entry with an 2697 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc 2698 // is resolved lazily, so the GOT entry needs to be in 2699 // an area in .got.plt, not .got. Call got_section to 2700 // make sure the section has been created. 2701 target->got_section(symtab, layout); 2702 Output_data_got<64, false>* got = target->got_tlsdesc_section(); 2703 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2704 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) 2705 { 2706 unsigned int got_offset = got->add_constant(0); 2707 got->add_constant(0); 2708 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, 2709 got_offset); 2710 Reloc_section* rt = target->rela_tlsdesc_section(layout); 2711 // We store the arguments we need in a vector, and 2712 // use the index into the vector as the parameter 2713 // to pass to the target specific routines. 2714 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym); 2715 void* arg = reinterpret_cast<void*>(intarg); 2716 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, 2717 got, got_offset, 0); 2718 } 2719 } 2720 else if (optimized_type != tls::TLSOPT_TO_LE) 2721 unsupported_reloc_local(object, r_type); 2722 break; 2723 2724 case elfcpp::R_X86_64_TLSDESC_CALL: 2725 break; 2726 2727 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 2728 if (optimized_type == tls::TLSOPT_NONE) 2729 { 2730 // Create a GOT entry for the module index. 2731 target->got_mod_index_entry(symtab, layout, object); 2732 } 2733 else if (optimized_type != tls::TLSOPT_TO_LE) 2734 unsupported_reloc_local(object, r_type); 2735 break; 2736 2737 case elfcpp::R_X86_64_DTPOFF32: 2738 case elfcpp::R_X86_64_DTPOFF64: 2739 break; 2740 2741 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 2742 layout->set_has_static_tls(); 2743 if (optimized_type == tls::TLSOPT_NONE) 2744 { 2745 // Create a GOT entry for the tp-relative offset. 2746 Output_data_got<64, false>* got 2747 = target->got_section(symtab, layout); 2748 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 2749 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET, 2750 target->rela_dyn_section(layout), 2751 elfcpp::R_X86_64_TPOFF64); 2752 } 2753 else if (optimized_type != tls::TLSOPT_TO_LE) 2754 unsupported_reloc_local(object, r_type); 2755 break; 2756 2757 case elfcpp::R_X86_64_TPOFF32: // Local-exec 2758 layout->set_has_static_tls(); 2759 if (output_is_shared) 2760 unsupported_reloc_local(object, r_type); 2761 break; 2762 2763 default: 2764 gold_unreachable(); 2765 } 2766 } 2767 break; 2768 2769 case elfcpp::R_X86_64_SIZE32: 2770 case elfcpp::R_X86_64_SIZE64: 2771 default: 2772 gold_error(_("%s: unsupported reloc %u against local symbol"), 2773 object->name().c_str(), r_type); 2774 break; 2775 } 2776 } 2777 2778 2779 // Report an unsupported relocation against a global symbol. 2780 2781 template<int size> 2782 void 2783 Target_x86_64<size>::Scan::unsupported_reloc_global( 2784 Sized_relobj_file<size, false>* object, 2785 unsigned int r_type, 2786 Symbol* gsym) 2787 { 2788 gold_error(_("%s: unsupported reloc %u against global symbol %s"), 2789 object->name().c_str(), r_type, gsym->demangled_name().c_str()); 2790 } 2791 2792 // Returns true if this relocation type could be that of a function pointer. 2793 template<int size> 2794 inline bool 2795 Target_x86_64<size>::Scan::possible_function_pointer_reloc(unsigned int r_type) 2796 { 2797 switch (r_type) 2798 { 2799 case elfcpp::R_X86_64_64: 2800 case elfcpp::R_X86_64_32: 2801 case elfcpp::R_X86_64_32S: 2802 case elfcpp::R_X86_64_16: 2803 case elfcpp::R_X86_64_8: 2804 case elfcpp::R_X86_64_GOT64: 2805 case elfcpp::R_X86_64_GOT32: 2806 case elfcpp::R_X86_64_GOTPCREL64: 2807 case elfcpp::R_X86_64_GOTPCREL: 2808 case elfcpp::R_X86_64_GOTPCRELX: 2809 case elfcpp::R_X86_64_REX_GOTPCRELX: 2810 case elfcpp::R_X86_64_GOTPLT64: 2811 { 2812 return true; 2813 } 2814 } 2815 return false; 2816 } 2817 2818 // For safe ICF, scan a relocation for a local symbol to check if it 2819 // corresponds to a function pointer being taken. In that case mark 2820 // the function whose pointer was taken as not foldable. 2821 2822 template<int size> 2823 inline bool 2824 Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer( 2825 Symbol_table* , 2826 Layout* , 2827 Target_x86_64<size>* , 2828 Sized_relobj_file<size, false>* , 2829 unsigned int , 2830 Output_section* , 2831 const elfcpp::Rela<size, false>& , 2832 unsigned int r_type, 2833 const elfcpp::Sym<size, false>&) 2834 { 2835 // When building a shared library, do not fold any local symbols as it is 2836 // not possible to distinguish pointer taken versus a call by looking at 2837 // the relocation types. 2838 return (parameters->options().shared() 2839 || possible_function_pointer_reloc(r_type)); 2840 } 2841 2842 // For safe ICF, scan a relocation for a global symbol to check if it 2843 // corresponds to a function pointer being taken. In that case mark 2844 // the function whose pointer was taken as not foldable. 2845 2846 template<int size> 2847 inline bool 2848 Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer( 2849 Symbol_table*, 2850 Layout* , 2851 Target_x86_64<size>* , 2852 Sized_relobj_file<size, false>* , 2853 unsigned int , 2854 Output_section* , 2855 const elfcpp::Rela<size, false>& , 2856 unsigned int r_type, 2857 Symbol* gsym) 2858 { 2859 // When building a shared library, do not fold symbols whose visibility 2860 // is hidden, internal or protected. 2861 return ((parameters->options().shared() 2862 && (gsym->visibility() == elfcpp::STV_INTERNAL 2863 || gsym->visibility() == elfcpp::STV_PROTECTED 2864 || gsym->visibility() == elfcpp::STV_HIDDEN)) 2865 || possible_function_pointer_reloc(r_type)); 2866 } 2867 2868 // Scan a relocation for a global symbol. 2869 2870 template<int size> 2871 inline void 2872 Target_x86_64<size>::Scan::global(Symbol_table* symtab, 2873 Layout* layout, 2874 Target_x86_64<size>* target, 2875 Sized_relobj_file<size, false>* object, 2876 unsigned int data_shndx, 2877 Output_section* output_section, 2878 const elfcpp::Rela<size, false>& reloc, 2879 unsigned int r_type, 2880 Symbol* gsym) 2881 { 2882 // A STT_GNU_IFUNC symbol may require a PLT entry. 2883 if (gsym->type() == elfcpp::STT_GNU_IFUNC 2884 && this->reloc_needs_plt_for_ifunc(object, r_type)) 2885 target->make_plt_entry(symtab, layout, gsym); 2886 2887 switch (r_type) 2888 { 2889 case elfcpp::R_X86_64_NONE: 2890 case elfcpp::R_X86_64_GNU_VTINHERIT: 2891 case elfcpp::R_X86_64_GNU_VTENTRY: 2892 break; 2893 2894 case elfcpp::R_X86_64_64: 2895 case elfcpp::R_X86_64_32: 2896 case elfcpp::R_X86_64_32S: 2897 case elfcpp::R_X86_64_16: 2898 case elfcpp::R_X86_64_8: 2899 { 2900 // Make a PLT entry if necessary. 2901 if (gsym->needs_plt_entry()) 2902 { 2903 target->make_plt_entry(symtab, layout, gsym); 2904 // Since this is not a PC-relative relocation, we may be 2905 // taking the address of a function. In that case we need to 2906 // set the entry in the dynamic symbol table to the address of 2907 // the PLT entry. 2908 if (gsym->is_from_dynobj() && !parameters->options().shared()) 2909 gsym->set_needs_dynsym_value(); 2910 } 2911 // Make a dynamic relocation if necessary. 2912 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) 2913 { 2914 if (!parameters->options().output_is_position_independent() 2915 && gsym->may_need_copy_reloc()) 2916 { 2917 target->copy_reloc(symtab, layout, object, 2918 data_shndx, output_section, gsym, reloc); 2919 } 2920 else if (((size == 64 && r_type == elfcpp::R_X86_64_64) 2921 || (size == 32 && r_type == elfcpp::R_X86_64_32)) 2922 && gsym->type() == elfcpp::STT_GNU_IFUNC 2923 && gsym->can_use_relative_reloc(false) 2924 && !gsym->is_from_dynobj() 2925 && !gsym->is_undefined() 2926 && !gsym->is_preemptible()) 2927 { 2928 // Use an IRELATIVE reloc for a locally defined 2929 // STT_GNU_IFUNC symbol. This makes a function 2930 // address in a PIE executable match the address in a 2931 // shared library that it links against. 2932 Reloc_section* rela_dyn = 2933 target->rela_irelative_section(layout); 2934 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE; 2935 rela_dyn->add_symbolless_global_addend(gsym, r_type, 2936 output_section, object, 2937 data_shndx, 2938 reloc.get_r_offset(), 2939 reloc.get_r_addend()); 2940 } 2941 else if (((size == 64 && r_type == elfcpp::R_X86_64_64) 2942 || (size == 32 && r_type == elfcpp::R_X86_64_32)) 2943 && gsym->can_use_relative_reloc(false)) 2944 { 2945 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2946 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, 2947 output_section, object, 2948 data_shndx, 2949 reloc.get_r_offset(), 2950 reloc.get_r_addend(), false); 2951 } 2952 else 2953 { 2954 this->check_non_pic(object, r_type, gsym); 2955 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2956 rela_dyn->add_global(gsym, r_type, output_section, object, 2957 data_shndx, reloc.get_r_offset(), 2958 reloc.get_r_addend()); 2959 } 2960 } 2961 } 2962 break; 2963 2964 case elfcpp::R_X86_64_PC64: 2965 case elfcpp::R_X86_64_PC32: 2966 case elfcpp::R_X86_64_PC32_BND: 2967 case elfcpp::R_X86_64_PC16: 2968 case elfcpp::R_X86_64_PC8: 2969 { 2970 // Make a PLT entry if necessary. 2971 if (gsym->needs_plt_entry()) 2972 target->make_plt_entry(symtab, layout, gsym); 2973 // Make a dynamic relocation if necessary. 2974 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) 2975 { 2976 if (parameters->options().output_is_executable() 2977 && gsym->may_need_copy_reloc()) 2978 { 2979 target->copy_reloc(symtab, layout, object, 2980 data_shndx, output_section, gsym, reloc); 2981 } 2982 else 2983 { 2984 this->check_non_pic(object, r_type, gsym); 2985 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 2986 rela_dyn->add_global(gsym, r_type, output_section, object, 2987 data_shndx, reloc.get_r_offset(), 2988 reloc.get_r_addend()); 2989 } 2990 } 2991 } 2992 break; 2993 2994 case elfcpp::R_X86_64_GOT64: 2995 case elfcpp::R_X86_64_GOT32: 2996 case elfcpp::R_X86_64_GOTPCREL64: 2997 case elfcpp::R_X86_64_GOTPCREL: 2998 case elfcpp::R_X86_64_GOTPCRELX: 2999 case elfcpp::R_X86_64_REX_GOTPCRELX: 3000 case elfcpp::R_X86_64_GOTPLT64: 3001 { 3002 // The symbol requires a GOT entry. 3003 Output_data_got<64, false>* got = target->got_section(symtab, layout); 3004 3005 // If we convert this from 3006 // mov foo@GOTPCREL(%rip), %reg 3007 // to lea foo(%rip), %reg. 3008 // OR 3009 // if we convert 3010 // (callq|jmpq) *foo@GOTPCRELX(%rip) to 3011 // (callq|jmpq) foo 3012 // in Relocate::relocate, then there is nothing to do here. 3013 3014 Lazy_view<size> view(object, data_shndx); 3015 size_t r_offset = reloc.get_r_offset(); 3016 if (r_offset >= 2 3017 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type, 3018 r_offset, &view)) 3019 break; 3020 3021 if (r_offset >= 2 3022 && Target_x86_64<size>::can_convert_callq_to_direct(gsym, r_type, 3023 r_offset, 3024 &view)) 3025 break; 3026 3027 if (gsym->final_value_is_known()) 3028 { 3029 // For a STT_GNU_IFUNC symbol we want the PLT address. 3030 if (gsym->type() == elfcpp::STT_GNU_IFUNC) 3031 got->add_global_plt(gsym, GOT_TYPE_STANDARD); 3032 else 3033 got->add_global(gsym, GOT_TYPE_STANDARD); 3034 } 3035 else 3036 { 3037 // If this symbol is not fully resolved, we need to add a 3038 // dynamic relocation for it. 3039 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3040 3041 // Use a GLOB_DAT rather than a RELATIVE reloc if: 3042 // 3043 // 1) The symbol may be defined in some other module. 3044 // 3045 // 2) We are building a shared library and this is a 3046 // protected symbol; using GLOB_DAT means that the dynamic 3047 // linker can use the address of the PLT in the main 3048 // executable when appropriate so that function address 3049 // comparisons work. 3050 // 3051 // 3) This is a STT_GNU_IFUNC symbol in position dependent 3052 // code, again so that function address comparisons work. 3053 if (gsym->is_from_dynobj() 3054 || gsym->is_undefined() 3055 || gsym->is_preemptible() 3056 || (gsym->visibility() == elfcpp::STV_PROTECTED 3057 && parameters->options().shared()) 3058 || (gsym->type() == elfcpp::STT_GNU_IFUNC 3059 && parameters->options().output_is_position_independent())) 3060 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn, 3061 elfcpp::R_X86_64_GLOB_DAT); 3062 else 3063 { 3064 // For a STT_GNU_IFUNC symbol we want to write the PLT 3065 // offset into the GOT, so that function pointer 3066 // comparisons work correctly. 3067 bool is_new; 3068 if (gsym->type() != elfcpp::STT_GNU_IFUNC) 3069 is_new = got->add_global(gsym, GOT_TYPE_STANDARD); 3070 else 3071 { 3072 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); 3073 // Tell the dynamic linker to use the PLT address 3074 // when resolving relocations. 3075 if (gsym->is_from_dynobj() 3076 && !parameters->options().shared()) 3077 gsym->set_needs_dynsym_value(); 3078 } 3079 if (is_new) 3080 { 3081 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); 3082 rela_dyn->add_global_relative(gsym, 3083 elfcpp::R_X86_64_RELATIVE, 3084 got, got_off, 0, false); 3085 } 3086 } 3087 } 3088 } 3089 break; 3090 3091 case elfcpp::R_X86_64_PLT32: 3092 case elfcpp::R_X86_64_PLT32_BND: 3093 // If the symbol is fully resolved, this is just a PC32 reloc. 3094 // Otherwise we need a PLT entry. 3095 if (gsym->final_value_is_known()) 3096 break; 3097 // If building a shared library, we can also skip the PLT entry 3098 // if the symbol is defined in the output file and is protected 3099 // or hidden. 3100 if (gsym->is_defined() 3101 && !gsym->is_from_dynobj() 3102 && !gsym->is_preemptible()) 3103 break; 3104 target->make_plt_entry(symtab, layout, gsym); 3105 break; 3106 3107 case elfcpp::R_X86_64_GOTPC32: 3108 case elfcpp::R_X86_64_GOTOFF64: 3109 case elfcpp::R_X86_64_GOTPC64: 3110 case elfcpp::R_X86_64_PLTOFF64: 3111 // We need a GOT section. 3112 target->got_section(symtab, layout); 3113 // For PLTOFF64, we also need a PLT entry (but only if the 3114 // symbol is not fully resolved). 3115 if (r_type == elfcpp::R_X86_64_PLTOFF64 3116 && !gsym->final_value_is_known()) 3117 target->make_plt_entry(symtab, layout, gsym); 3118 break; 3119 3120 case elfcpp::R_X86_64_COPY: 3121 case elfcpp::R_X86_64_GLOB_DAT: 3122 case elfcpp::R_X86_64_JUMP_SLOT: 3123 case elfcpp::R_X86_64_RELATIVE: 3124 case elfcpp::R_X86_64_IRELATIVE: 3125 // These are outstanding tls relocs, which are unexpected when linking 3126 case elfcpp::R_X86_64_TPOFF64: 3127 case elfcpp::R_X86_64_DTPMOD64: 3128 case elfcpp::R_X86_64_TLSDESC: 3129 gold_error(_("%s: unexpected reloc %u in object file"), 3130 object->name().c_str(), r_type); 3131 break; 3132 3133 // These are initial tls relocs, which are expected for global() 3134 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 3135 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 3136 case elfcpp::R_X86_64_TLSDESC_CALL: 3137 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3138 case elfcpp::R_X86_64_DTPOFF32: 3139 case elfcpp::R_X86_64_DTPOFF64: 3140 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3141 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3142 { 3143 // For the Initial-Exec model, we can treat undef symbols as final 3144 // when building an executable. 3145 const bool is_final = (gsym->final_value_is_known() || 3146 (r_type == elfcpp::R_X86_64_GOTTPOFF && 3147 gsym->is_undefined() && 3148 parameters->options().output_is_executable())); 3149 const tls::Tls_optimization optimized_type 3150 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type); 3151 switch (r_type) 3152 { 3153 case elfcpp::R_X86_64_TLSGD: // General-dynamic 3154 if (optimized_type == tls::TLSOPT_NONE) 3155 { 3156 // Create a pair of GOT entries for the module index and 3157 // dtv-relative offset. 3158 Output_data_got<64, false>* got 3159 = target->got_section(symtab, layout); 3160 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, 3161 target->rela_dyn_section(layout), 3162 elfcpp::R_X86_64_DTPMOD64, 3163 elfcpp::R_X86_64_DTPOFF64); 3164 } 3165 else if (optimized_type == tls::TLSOPT_TO_IE) 3166 { 3167 // Create a GOT entry for the tp-relative offset. 3168 Output_data_got<64, false>* got 3169 = target->got_section(symtab, layout); 3170 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 3171 target->rela_dyn_section(layout), 3172 elfcpp::R_X86_64_TPOFF64); 3173 } 3174 else if (optimized_type != tls::TLSOPT_TO_LE) 3175 unsupported_reloc_global(object, r_type, gsym); 3176 break; 3177 3178 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 3179 target->define_tls_base_symbol(symtab, layout); 3180 if (optimized_type == tls::TLSOPT_NONE) 3181 { 3182 // Create reserved PLT and GOT entries for the resolver. 3183 target->reserve_tlsdesc_entries(symtab, layout); 3184 3185 // Create a double GOT entry with an R_X86_64_TLSDESC 3186 // reloc. The R_X86_64_TLSDESC reloc is resolved 3187 // lazily, so the GOT entry needs to be in an area in 3188 // .got.plt, not .got. Call got_section to make sure 3189 // the section has been created. 3190 target->got_section(symtab, layout); 3191 Output_data_got<64, false>* got = target->got_tlsdesc_section(); 3192 Reloc_section* rt = target->rela_tlsdesc_section(layout); 3193 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, 3194 elfcpp::R_X86_64_TLSDESC, 0); 3195 } 3196 else if (optimized_type == tls::TLSOPT_TO_IE) 3197 { 3198 // Create a GOT entry for the tp-relative offset. 3199 Output_data_got<64, false>* got 3200 = target->got_section(symtab, layout); 3201 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 3202 target->rela_dyn_section(layout), 3203 elfcpp::R_X86_64_TPOFF64); 3204 } 3205 else if (optimized_type != tls::TLSOPT_TO_LE) 3206 unsupported_reloc_global(object, r_type, gsym); 3207 break; 3208 3209 case elfcpp::R_X86_64_TLSDESC_CALL: 3210 break; 3211 3212 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3213 if (optimized_type == tls::TLSOPT_NONE) 3214 { 3215 // Create a GOT entry for the module index. 3216 target->got_mod_index_entry(symtab, layout, object); 3217 } 3218 else if (optimized_type != tls::TLSOPT_TO_LE) 3219 unsupported_reloc_global(object, r_type, gsym); 3220 break; 3221 3222 case elfcpp::R_X86_64_DTPOFF32: 3223 case elfcpp::R_X86_64_DTPOFF64: 3224 break; 3225 3226 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3227 layout->set_has_static_tls(); 3228 if (optimized_type == tls::TLSOPT_NONE) 3229 { 3230 // Create a GOT entry for the tp-relative offset. 3231 Output_data_got<64, false>* got 3232 = target->got_section(symtab, layout); 3233 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 3234 target->rela_dyn_section(layout), 3235 elfcpp::R_X86_64_TPOFF64); 3236 } 3237 else if (optimized_type != tls::TLSOPT_TO_LE) 3238 unsupported_reloc_global(object, r_type, gsym); 3239 break; 3240 3241 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3242 layout->set_has_static_tls(); 3243 if (parameters->options().shared()) 3244 unsupported_reloc_global(object, r_type, gsym); 3245 break; 3246 3247 default: 3248 gold_unreachable(); 3249 } 3250 } 3251 break; 3252 3253 case elfcpp::R_X86_64_SIZE32: 3254 case elfcpp::R_X86_64_SIZE64: 3255 default: 3256 gold_error(_("%s: unsupported reloc %u against global symbol %s"), 3257 object->name().c_str(), r_type, 3258 gsym->demangled_name().c_str()); 3259 break; 3260 } 3261 } 3262 3263 template<int size> 3264 void 3265 Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab, 3266 Layout* layout, 3267 Sized_relobj_file<size, false>* object, 3268 unsigned int data_shndx, 3269 unsigned int sh_type, 3270 const unsigned char* prelocs, 3271 size_t reloc_count, 3272 Output_section* output_section, 3273 bool needs_special_offset_handling, 3274 size_t local_symbol_count, 3275 const unsigned char* plocal_symbols) 3276 { 3277 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 3278 Classify_reloc; 3279 3280 if (sh_type == elfcpp::SHT_REL) 3281 { 3282 return; 3283 } 3284 3285 gold::gc_process_relocs<size, false, Target_x86_64<size>, Scan, 3286 Classify_reloc>( 3287 symtab, 3288 layout, 3289 this, 3290 object, 3291 data_shndx, 3292 prelocs, 3293 reloc_count, 3294 output_section, 3295 needs_special_offset_handling, 3296 local_symbol_count, 3297 plocal_symbols); 3298 3299 } 3300 // Scan relocations for a section. 3301 3302 template<int size> 3303 void 3304 Target_x86_64<size>::scan_relocs(Symbol_table* symtab, 3305 Layout* layout, 3306 Sized_relobj_file<size, false>* object, 3307 unsigned int data_shndx, 3308 unsigned int sh_type, 3309 const unsigned char* prelocs, 3310 size_t reloc_count, 3311 Output_section* output_section, 3312 bool needs_special_offset_handling, 3313 size_t local_symbol_count, 3314 const unsigned char* plocal_symbols) 3315 { 3316 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 3317 Classify_reloc; 3318 3319 if (sh_type == elfcpp::SHT_REL) 3320 { 3321 gold_error(_("%s: unsupported REL reloc section"), 3322 object->name().c_str()); 3323 return; 3324 } 3325 3326 gold::scan_relocs<size, false, Target_x86_64<size>, Scan, Classify_reloc>( 3327 symtab, 3328 layout, 3329 this, 3330 object, 3331 data_shndx, 3332 prelocs, 3333 reloc_count, 3334 output_section, 3335 needs_special_offset_handling, 3336 local_symbol_count, 3337 plocal_symbols); 3338 } 3339 3340 // Finalize the sections. 3341 3342 template<int size> 3343 void 3344 Target_x86_64<size>::do_finalize_sections( 3345 Layout* layout, 3346 const Input_objects*, 3347 Symbol_table* symtab) 3348 { 3349 const Reloc_section* rel_plt = (this->plt_ == NULL 3350 ? NULL 3351 : this->plt_->rela_plt()); 3352 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt, 3353 this->rela_dyn_, true, false); 3354 3355 // Fill in some more dynamic tags. 3356 Output_data_dynamic* const odyn = layout->dynamic_data(); 3357 if (odyn != NULL) 3358 { 3359 if (this->plt_ != NULL 3360 && this->plt_->output_section() != NULL 3361 && this->plt_->has_tlsdesc_entry()) 3362 { 3363 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset(); 3364 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset(); 3365 this->got_->finalize_data_size(); 3366 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT, 3367 this->plt_, plt_offset); 3368 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT, 3369 this->got_, got_offset); 3370 } 3371 } 3372 3373 // Emit any relocs we saved in an attempt to avoid generating COPY 3374 // relocs. 3375 if (this->copy_relocs_.any_saved_relocs()) 3376 this->copy_relocs_.emit(this->rela_dyn_section(layout)); 3377 3378 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of 3379 // the .got.plt section. 3380 Symbol* sym = this->global_offset_table_; 3381 if (sym != NULL) 3382 { 3383 uint64_t data_size = this->got_plt_->current_data_size(); 3384 symtab->get_sized_symbol<size>(sym)->set_symsize(data_size); 3385 } 3386 3387 if (parameters->doing_static_link() 3388 && (this->plt_ == NULL || !this->plt_->has_irelative_section())) 3389 { 3390 // If linking statically, make sure that the __rela_iplt symbols 3391 // were defined if necessary, even if we didn't create a PLT. 3392 static const Define_symbol_in_segment syms[] = 3393 { 3394 { 3395 "__rela_iplt_start", // name 3396 elfcpp::PT_LOAD, // segment_type 3397 elfcpp::PF_W, // segment_flags_set 3398 elfcpp::PF(0), // segment_flags_clear 3399 0, // value 3400 0, // size 3401 elfcpp::STT_NOTYPE, // type 3402 elfcpp::STB_GLOBAL, // binding 3403 elfcpp::STV_HIDDEN, // visibility 3404 0, // nonvis 3405 Symbol::SEGMENT_START, // offset_from_base 3406 true // only_if_ref 3407 }, 3408 { 3409 "__rela_iplt_end", // name 3410 elfcpp::PT_LOAD, // segment_type 3411 elfcpp::PF_W, // segment_flags_set 3412 elfcpp::PF(0), // segment_flags_clear 3413 0, // value 3414 0, // size 3415 elfcpp::STT_NOTYPE, // type 3416 elfcpp::STB_GLOBAL, // binding 3417 elfcpp::STV_HIDDEN, // visibility 3418 0, // nonvis 3419 Symbol::SEGMENT_START, // offset_from_base 3420 true // only_if_ref 3421 } 3422 }; 3423 3424 symtab->define_symbols(layout, 2, syms, 3425 layout->script_options()->saw_sections_clause()); 3426 } 3427 } 3428 3429 // For x32, we need to handle PC-relative relocations using full 64-bit 3430 // arithmetic, so that we can detect relocation overflows properly. 3431 // This class overrides the pcrela32_check methods from the defaults in 3432 // Relocate_functions in reloc.h. 3433 3434 template<int size> 3435 class X86_64_relocate_functions : public Relocate_functions<size, false> 3436 { 3437 public: 3438 typedef Relocate_functions<size, false> Base; 3439 3440 // Do a simple PC relative relocation with the addend in the 3441 // relocation. 3442 static inline typename Base::Reloc_status 3443 pcrela32_check(unsigned char* view, 3444 typename elfcpp::Elf_types<64>::Elf_Addr value, 3445 typename elfcpp::Elf_types<64>::Elf_Swxword addend, 3446 typename elfcpp::Elf_types<64>::Elf_Addr address) 3447 { 3448 typedef typename elfcpp::Swap<32, false>::Valtype Valtype; 3449 Valtype* wv = reinterpret_cast<Valtype*>(view); 3450 value = value + addend - address; 3451 elfcpp::Swap<32, false>::writeval(wv, value); 3452 return (Bits<32>::has_overflow(value) 3453 ? Base::RELOC_OVERFLOW : Base::RELOC_OK); 3454 } 3455 3456 // Do a simple PC relative relocation with a Symbol_value with the 3457 // addend in the relocation. 3458 static inline typename Base::Reloc_status 3459 pcrela32_check(unsigned char* view, 3460 const Sized_relobj_file<size, false>* object, 3461 const Symbol_value<size>* psymval, 3462 typename elfcpp::Elf_types<64>::Elf_Swxword addend, 3463 typename elfcpp::Elf_types<64>::Elf_Addr address) 3464 { 3465 typedef typename elfcpp::Swap<32, false>::Valtype Valtype; 3466 Valtype* wv = reinterpret_cast<Valtype*>(view); 3467 typename elfcpp::Elf_types<64>::Elf_Addr value; 3468 if (addend >= 0) 3469 value = psymval->value(object, addend); 3470 else 3471 { 3472 // For negative addends, get the symbol value without 3473 // the addend, then add the addend using 64-bit arithmetic. 3474 value = psymval->value(object, 0); 3475 value += addend; 3476 } 3477 value -= address; 3478 elfcpp::Swap<32, false>::writeval(wv, value); 3479 return (Bits<32>::has_overflow(value) 3480 ? Base::RELOC_OVERFLOW : Base::RELOC_OK); 3481 } 3482 }; 3483 3484 // Perform a relocation. 3485 3486 template<int size> 3487 inline bool 3488 Target_x86_64<size>::Relocate::relocate( 3489 const Relocate_info<size, false>* relinfo, 3490 unsigned int, 3491 Target_x86_64<size>* target, 3492 Output_section*, 3493 size_t relnum, 3494 const unsigned char* preloc, 3495 const Sized_symbol<size>* gsym, 3496 const Symbol_value<size>* psymval, 3497 unsigned char* view, 3498 typename elfcpp::Elf_types<size>::Elf_Addr address, 3499 section_size_type view_size) 3500 { 3501 typedef X86_64_relocate_functions<size> Reloc_funcs; 3502 const elfcpp::Rela<size, false> rela(preloc); 3503 unsigned int r_type = elfcpp::elf_r_type<size>(rela.get_r_info()); 3504 3505 if (this->skip_call_tls_get_addr_) 3506 { 3507 if ((r_type != elfcpp::R_X86_64_PLT32 3508 && r_type != elfcpp::R_X86_64_GOTPCRELX 3509 && r_type != elfcpp::R_X86_64_PLT32_BND 3510 && r_type != elfcpp::R_X86_64_PC32_BND 3511 && r_type != elfcpp::R_X86_64_PC32) 3512 || gsym == NULL 3513 || strcmp(gsym->name(), "__tls_get_addr") != 0) 3514 { 3515 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3516 _("missing expected TLS relocation")); 3517 } 3518 else 3519 { 3520 this->skip_call_tls_get_addr_ = false; 3521 return false; 3522 } 3523 } 3524 3525 if (view == NULL) 3526 return true; 3527 3528 const Sized_relobj_file<size, false>* object = relinfo->object; 3529 3530 // Pick the value to use for symbols defined in the PLT. 3531 Symbol_value<size> symval; 3532 if (gsym != NULL 3533 && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) 3534 { 3535 symval.set_output_value(target->plt_address_for_global(gsym)); 3536 psymval = &symval; 3537 } 3538 else if (gsym == NULL && psymval->is_ifunc_symbol()) 3539 { 3540 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3541 if (object->local_has_plt_offset(r_sym)) 3542 { 3543 symval.set_output_value(target->plt_address_for_local(object, r_sym)); 3544 psymval = &symval; 3545 } 3546 } 3547 3548 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 3549 3550 // Get the GOT offset if needed. 3551 // The GOT pointer points to the end of the GOT section. 3552 // We need to subtract the size of the GOT section to get 3553 // the actual offset to use in the relocation. 3554 bool have_got_offset = false; 3555 // Since the actual offset is always negative, we use signed int to 3556 // support 64-bit GOT relocations. 3557 int got_offset = 0; 3558 switch (r_type) 3559 { 3560 case elfcpp::R_X86_64_GOT32: 3561 case elfcpp::R_X86_64_GOT64: 3562 case elfcpp::R_X86_64_GOTPLT64: 3563 case elfcpp::R_X86_64_GOTPCREL64: 3564 if (gsym != NULL) 3565 { 3566 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); 3567 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size(); 3568 } 3569 else 3570 { 3571 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3572 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); 3573 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) 3574 - target->got_size()); 3575 } 3576 have_got_offset = true; 3577 break; 3578 3579 default: 3580 break; 3581 } 3582 3583 typename Reloc_funcs::Reloc_status rstatus = Reloc_funcs::RELOC_OK; 3584 3585 switch (r_type) 3586 { 3587 case elfcpp::R_X86_64_NONE: 3588 case elfcpp::R_X86_64_GNU_VTINHERIT: 3589 case elfcpp::R_X86_64_GNU_VTENTRY: 3590 break; 3591 3592 case elfcpp::R_X86_64_64: 3593 Reloc_funcs::rela64(view, object, psymval, addend); 3594 break; 3595 3596 case elfcpp::R_X86_64_PC64: 3597 Reloc_funcs::pcrela64(view, object, psymval, addend, 3598 address); 3599 break; 3600 3601 case elfcpp::R_X86_64_32: 3602 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend, 3603 Reloc_funcs::CHECK_UNSIGNED); 3604 break; 3605 3606 case elfcpp::R_X86_64_32S: 3607 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend, 3608 Reloc_funcs::CHECK_SIGNED); 3609 break; 3610 3611 case elfcpp::R_X86_64_PC32: 3612 case elfcpp::R_X86_64_PC32_BND: 3613 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend, 3614 address); 3615 break; 3616 3617 case elfcpp::R_X86_64_16: 3618 Reloc_funcs::rela16(view, object, psymval, addend); 3619 break; 3620 3621 case elfcpp::R_X86_64_PC16: 3622 Reloc_funcs::pcrela16(view, object, psymval, addend, address); 3623 break; 3624 3625 case elfcpp::R_X86_64_8: 3626 Reloc_funcs::rela8(view, object, psymval, addend); 3627 break; 3628 3629 case elfcpp::R_X86_64_PC8: 3630 Reloc_funcs::pcrela8(view, object, psymval, addend, address); 3631 break; 3632 3633 case elfcpp::R_X86_64_PLT32: 3634 case elfcpp::R_X86_64_PLT32_BND: 3635 gold_assert(gsym == NULL 3636 || gsym->has_plt_offset() 3637 || gsym->final_value_is_known() 3638 || (gsym->is_defined() 3639 && !gsym->is_from_dynobj() 3640 && !gsym->is_preemptible())); 3641 // Note: while this code looks the same as for R_X86_64_PC32, it 3642 // behaves differently because psymval was set to point to 3643 // the PLT entry, rather than the symbol, in Scan::global(). 3644 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend, 3645 address); 3646 break; 3647 3648 case elfcpp::R_X86_64_PLTOFF64: 3649 { 3650 gold_assert(gsym); 3651 gold_assert(gsym->has_plt_offset() 3652 || gsym->final_value_is_known()); 3653 typename elfcpp::Elf_types<size>::Elf_Addr got_address; 3654 // This is the address of GLOBAL_OFFSET_TABLE. 3655 got_address = target->got_plt_section()->address(); 3656 Reloc_funcs::rela64(view, object, psymval, addend - got_address); 3657 } 3658 break; 3659 3660 case elfcpp::R_X86_64_GOT32: 3661 gold_assert(have_got_offset); 3662 Reloc_funcs::rela32(view, got_offset, addend); 3663 break; 3664 3665 case elfcpp::R_X86_64_GOTPC32: 3666 { 3667 gold_assert(gsym); 3668 typename elfcpp::Elf_types<size>::Elf_Addr value; 3669 value = target->got_plt_section()->address(); 3670 Reloc_funcs::pcrela32_check(view, value, addend, address); 3671 } 3672 break; 3673 3674 case elfcpp::R_X86_64_GOT64: 3675 case elfcpp::R_X86_64_GOTPLT64: 3676 // R_X86_64_GOTPLT64 is obsolete and treated the the same as 3677 // GOT64. 3678 gold_assert(have_got_offset); 3679 Reloc_funcs::rela64(view, got_offset, addend); 3680 break; 3681 3682 case elfcpp::R_X86_64_GOTPC64: 3683 { 3684 gold_assert(gsym); 3685 typename elfcpp::Elf_types<size>::Elf_Addr value; 3686 value = target->got_plt_section()->address(); 3687 Reloc_funcs::pcrela64(view, value, addend, address); 3688 } 3689 break; 3690 3691 case elfcpp::R_X86_64_GOTOFF64: 3692 { 3693 typename elfcpp::Elf_types<size>::Elf_Addr value; 3694 value = (psymval->value(object, 0) 3695 - target->got_plt_section()->address()); 3696 Reloc_funcs::rela64(view, value, addend); 3697 } 3698 break; 3699 3700 case elfcpp::R_X86_64_GOTPCREL: 3701 case elfcpp::R_X86_64_GOTPCRELX: 3702 case elfcpp::R_X86_64_REX_GOTPCRELX: 3703 { 3704 // Convert 3705 // mov foo@GOTPCREL(%rip), %reg 3706 // to lea foo(%rip), %reg. 3707 // if possible. 3708 if ((gsym == NULL 3709 && rela.get_r_offset() >= 2 3710 && view[-2] == 0x8b 3711 && !psymval->is_ifunc_symbol()) 3712 || (gsym != NULL 3713 && rela.get_r_offset() >= 2 3714 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type, 3715 0, &view))) 3716 { 3717 view[-2] = 0x8d; 3718 Reloc_funcs::pcrela32(view, object, psymval, addend, address); 3719 } 3720 // Convert 3721 // callq *foo@GOTPCRELX(%rip) to 3722 // addr32 callq foo 3723 // and jmpq *foo@GOTPCRELX(%rip) to 3724 // jmpq foo 3725 // nop 3726 else if (gsym != NULL 3727 && rela.get_r_offset() >= 2 3728 && Target_x86_64<size>::can_convert_callq_to_direct(gsym, 3729 r_type, 3730 0, &view)) 3731 { 3732 if (view[-1] == 0x15) 3733 { 3734 // Convert callq *foo@GOTPCRELX(%rip) to addr32 callq. 3735 // Opcode of addr32 is 0x67 and opcode of direct callq is 0xe8. 3736 view[-2] = 0x67; 3737 view[-1] = 0xe8; 3738 // Convert GOTPCRELX to 32-bit pc relative reloc. 3739 Reloc_funcs::pcrela32(view, object, psymval, addend, address); 3740 } 3741 else 3742 { 3743 // Convert jmpq *foo@GOTPCRELX(%rip) to 3744 // jmpq foo 3745 // nop 3746 // The opcode of direct jmpq is 0xe9. 3747 view[-2] = 0xe9; 3748 // The opcode of nop is 0x90. 3749 view[3] = 0x90; 3750 // Convert GOTPCRELX to 32-bit pc relative reloc. jmpq is rip 3751 // relative and since the instruction following the jmpq is now 3752 // the nop, offset the address by 1 byte. The start of the 3753 // relocation also moves ahead by 1 byte. 3754 Reloc_funcs::pcrela32(&view[-1], object, psymval, addend, 3755 address - 1); 3756 } 3757 } 3758 else 3759 { 3760 if (gsym != NULL) 3761 { 3762 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); 3763 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size(); 3764 } 3765 else 3766 { 3767 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3768 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); 3769 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) 3770 - target->got_size()); 3771 } 3772 typename elfcpp::Elf_types<size>::Elf_Addr value; 3773 value = target->got_plt_section()->address() + got_offset; 3774 Reloc_funcs::pcrela32_check(view, value, addend, address); 3775 } 3776 } 3777 break; 3778 3779 case elfcpp::R_X86_64_GOTPCREL64: 3780 { 3781 gold_assert(have_got_offset); 3782 typename elfcpp::Elf_types<size>::Elf_Addr value; 3783 value = target->got_plt_section()->address() + got_offset; 3784 Reloc_funcs::pcrela64(view, value, addend, address); 3785 } 3786 break; 3787 3788 case elfcpp::R_X86_64_COPY: 3789 case elfcpp::R_X86_64_GLOB_DAT: 3790 case elfcpp::R_X86_64_JUMP_SLOT: 3791 case elfcpp::R_X86_64_RELATIVE: 3792 case elfcpp::R_X86_64_IRELATIVE: 3793 // These are outstanding tls relocs, which are unexpected when linking 3794 case elfcpp::R_X86_64_TPOFF64: 3795 case elfcpp::R_X86_64_DTPMOD64: 3796 case elfcpp::R_X86_64_TLSDESC: 3797 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3798 _("unexpected reloc %u in object file"), 3799 r_type); 3800 break; 3801 3802 // These are initial tls relocs, which are expected when linking 3803 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 3804 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 3805 case elfcpp::R_X86_64_TLSDESC_CALL: 3806 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3807 case elfcpp::R_X86_64_DTPOFF32: 3808 case elfcpp::R_X86_64_DTPOFF64: 3809 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3810 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3811 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval, 3812 view, address, view_size); 3813 break; 3814 3815 case elfcpp::R_X86_64_SIZE32: 3816 case elfcpp::R_X86_64_SIZE64: 3817 default: 3818 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3819 _("unsupported reloc %u"), 3820 r_type); 3821 break; 3822 } 3823 3824 if (rstatus == Reloc_funcs::RELOC_OVERFLOW) 3825 { 3826 if (gsym == NULL) 3827 { 3828 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3829 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3830 _("relocation overflow: " 3831 "reference to local symbol %u in %s"), 3832 r_sym, object->name().c_str()); 3833 } 3834 else if (gsym->is_defined() && gsym->source() == Symbol::FROM_OBJECT) 3835 { 3836 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3837 _("relocation overflow: " 3838 "reference to '%s' defined in %s"), 3839 gsym->name(), 3840 gsym->object()->name().c_str()); 3841 } 3842 else 3843 { 3844 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3845 _("relocation overflow: reference to '%s'"), 3846 gsym->name()); 3847 } 3848 } 3849 3850 return true; 3851 } 3852 3853 // Perform a TLS relocation. 3854 3855 template<int size> 3856 inline void 3857 Target_x86_64<size>::Relocate::relocate_tls( 3858 const Relocate_info<size, false>* relinfo, 3859 Target_x86_64<size>* target, 3860 size_t relnum, 3861 const elfcpp::Rela<size, false>& rela, 3862 unsigned int r_type, 3863 const Sized_symbol<size>* gsym, 3864 const Symbol_value<size>* psymval, 3865 unsigned char* view, 3866 typename elfcpp::Elf_types<size>::Elf_Addr address, 3867 section_size_type view_size) 3868 { 3869 Output_segment* tls_segment = relinfo->layout->tls_segment(); 3870 3871 const Sized_relobj_file<size, false>* object = relinfo->object; 3872 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 3873 elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr); 3874 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0; 3875 3876 typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0); 3877 3878 const bool is_final = (gsym == NULL 3879 ? !parameters->options().shared() 3880 : gsym->final_value_is_known()); 3881 tls::Tls_optimization optimized_type 3882 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type); 3883 switch (r_type) 3884 { 3885 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 3886 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 3887 { 3888 // If this code sequence is used in a non-executable section, 3889 // we will not optimize the R_X86_64_DTPOFF32/64 relocation, 3890 // on the assumption that it's being used by itself in a debug 3891 // section. Therefore, in the unlikely event that the code 3892 // sequence appears in a non-executable section, we simply 3893 // leave it unoptimized. 3894 optimized_type = tls::TLSOPT_NONE; 3895 } 3896 if (optimized_type == tls::TLSOPT_TO_LE) 3897 { 3898 if (tls_segment == NULL) 3899 { 3900 gold_assert(parameters->errors()->error_count() > 0 3901 || issue_undefined_symbol_error(gsym)); 3902 return; 3903 } 3904 this->tls_gd_to_le(relinfo, relnum, tls_segment, 3905 rela, r_type, value, view, 3906 view_size); 3907 break; 3908 } 3909 else 3910 { 3911 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE 3912 ? GOT_TYPE_TLS_OFFSET 3913 : GOT_TYPE_TLS_PAIR); 3914 unsigned int got_offset; 3915 if (gsym != NULL) 3916 { 3917 gold_assert(gsym->has_got_offset(got_type)); 3918 got_offset = gsym->got_offset(got_type) - target->got_size(); 3919 } 3920 else 3921 { 3922 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3923 gold_assert(object->local_has_got_offset(r_sym, got_type)); 3924 got_offset = (object->local_got_offset(r_sym, got_type) 3925 - target->got_size()); 3926 } 3927 if (optimized_type == tls::TLSOPT_TO_IE) 3928 { 3929 value = target->got_plt_section()->address() + got_offset; 3930 this->tls_gd_to_ie(relinfo, relnum, rela, r_type, 3931 value, view, address, view_size); 3932 break; 3933 } 3934 else if (optimized_type == tls::TLSOPT_NONE) 3935 { 3936 // Relocate the field with the offset of the pair of GOT 3937 // entries. 3938 value = target->got_plt_section()->address() + got_offset; 3939 Relocate_functions<size, false>::pcrela32(view, value, addend, 3940 address); 3941 break; 3942 } 3943 } 3944 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 3945 _("unsupported reloc %u"), r_type); 3946 break; 3947 3948 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 3949 case elfcpp::R_X86_64_TLSDESC_CALL: 3950 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 3951 { 3952 // See above comment for R_X86_64_TLSGD. 3953 optimized_type = tls::TLSOPT_NONE; 3954 } 3955 if (optimized_type == tls::TLSOPT_TO_LE) 3956 { 3957 if (tls_segment == NULL) 3958 { 3959 gold_assert(parameters->errors()->error_count() > 0 3960 || issue_undefined_symbol_error(gsym)); 3961 return; 3962 } 3963 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, 3964 rela, r_type, value, view, 3965 view_size); 3966 break; 3967 } 3968 else 3969 { 3970 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE 3971 ? GOT_TYPE_TLS_OFFSET 3972 : GOT_TYPE_TLS_DESC); 3973 unsigned int got_offset = 0; 3974 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC 3975 && optimized_type == tls::TLSOPT_NONE) 3976 { 3977 // We created GOT entries in the .got.tlsdesc portion of 3978 // the .got.plt section, but the offset stored in the 3979 // symbol is the offset within .got.tlsdesc. 3980 got_offset = (target->got_size() 3981 + target->got_plt_section()->data_size()); 3982 } 3983 if (gsym != NULL) 3984 { 3985 gold_assert(gsym->has_got_offset(got_type)); 3986 got_offset += gsym->got_offset(got_type) - target->got_size(); 3987 } 3988 else 3989 { 3990 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 3991 gold_assert(object->local_has_got_offset(r_sym, got_type)); 3992 got_offset += (object->local_got_offset(r_sym, got_type) 3993 - target->got_size()); 3994 } 3995 if (optimized_type == tls::TLSOPT_TO_IE) 3996 { 3997 value = target->got_plt_section()->address() + got_offset; 3998 this->tls_desc_gd_to_ie(relinfo, relnum, 3999 rela, r_type, value, view, address, 4000 view_size); 4001 break; 4002 } 4003 else if (optimized_type == tls::TLSOPT_NONE) 4004 { 4005 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) 4006 { 4007 // Relocate the field with the offset of the pair of GOT 4008 // entries. 4009 value = target->got_plt_section()->address() + got_offset; 4010 Relocate_functions<size, false>::pcrela32(view, value, addend, 4011 address); 4012 } 4013 break; 4014 } 4015 } 4016 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4017 _("unsupported reloc %u"), r_type); 4018 break; 4019 4020 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 4021 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 4022 { 4023 // See above comment for R_X86_64_TLSGD. 4024 optimized_type = tls::TLSOPT_NONE; 4025 } 4026 if (optimized_type == tls::TLSOPT_TO_LE) 4027 { 4028 if (tls_segment == NULL) 4029 { 4030 gold_assert(parameters->errors()->error_count() > 0 4031 || issue_undefined_symbol_error(gsym)); 4032 return; 4033 } 4034 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type, 4035 value, view, view_size); 4036 break; 4037 } 4038 else if (optimized_type == tls::TLSOPT_NONE) 4039 { 4040 // Relocate the field with the offset of the GOT entry for 4041 // the module index. 4042 unsigned int got_offset; 4043 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) 4044 - target->got_size()); 4045 value = target->got_plt_section()->address() + got_offset; 4046 Relocate_functions<size, false>::pcrela32(view, value, addend, 4047 address); 4048 break; 4049 } 4050 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4051 _("unsupported reloc %u"), r_type); 4052 break; 4053 4054 case elfcpp::R_X86_64_DTPOFF32: 4055 // This relocation type is used in debugging information. 4056 // In that case we need to not optimize the value. If the 4057 // section is not executable, then we assume we should not 4058 // optimize this reloc. See comments above for R_X86_64_TLSGD, 4059 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and 4060 // R_X86_64_TLSLD. 4061 if (optimized_type == tls::TLSOPT_TO_LE && is_executable) 4062 { 4063 if (tls_segment == NULL) 4064 { 4065 gold_assert(parameters->errors()->error_count() > 0 4066 || issue_undefined_symbol_error(gsym)); 4067 return; 4068 } 4069 value -= tls_segment->memsz(); 4070 } 4071 Relocate_functions<size, false>::rela32(view, value, addend); 4072 break; 4073 4074 case elfcpp::R_X86_64_DTPOFF64: 4075 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable. 4076 if (optimized_type == tls::TLSOPT_TO_LE && is_executable) 4077 { 4078 if (tls_segment == NULL) 4079 { 4080 gold_assert(parameters->errors()->error_count() > 0 4081 || issue_undefined_symbol_error(gsym)); 4082 return; 4083 } 4084 value -= tls_segment->memsz(); 4085 } 4086 Relocate_functions<size, false>::rela64(view, value, addend); 4087 break; 4088 4089 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 4090 if (gsym != NULL 4091 && gsym->is_undefined() 4092 && parameters->options().output_is_executable()) 4093 { 4094 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum, 4095 NULL, rela, 4096 r_type, value, view, 4097 view_size); 4098 break; 4099 } 4100 else if (optimized_type == tls::TLSOPT_TO_LE) 4101 { 4102 if (tls_segment == NULL) 4103 { 4104 gold_assert(parameters->errors()->error_count() > 0 4105 || issue_undefined_symbol_error(gsym)); 4106 return; 4107 } 4108 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum, 4109 tls_segment, rela, 4110 r_type, value, view, 4111 view_size); 4112 break; 4113 } 4114 else if (optimized_type == tls::TLSOPT_NONE) 4115 { 4116 // Relocate the field with the offset of the GOT entry for 4117 // the tp-relative offset of the symbol. 4118 unsigned int got_offset; 4119 if (gsym != NULL) 4120 { 4121 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET)); 4122 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET) 4123 - target->got_size()); 4124 } 4125 else 4126 { 4127 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4128 gold_assert(object->local_has_got_offset(r_sym, 4129 GOT_TYPE_TLS_OFFSET)); 4130 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET) 4131 - target->got_size()); 4132 } 4133 value = target->got_plt_section()->address() + got_offset; 4134 Relocate_functions<size, false>::pcrela32(view, value, addend, 4135 address); 4136 break; 4137 } 4138 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4139 _("unsupported reloc type %u"), 4140 r_type); 4141 break; 4142 4143 case elfcpp::R_X86_64_TPOFF32: // Local-exec 4144 if (tls_segment == NULL) 4145 { 4146 gold_assert(parameters->errors()->error_count() > 0 4147 || issue_undefined_symbol_error(gsym)); 4148 return; 4149 } 4150 value -= tls_segment->memsz(); 4151 Relocate_functions<size, false>::rela32(view, value, addend); 4152 break; 4153 } 4154 } 4155 4156 // Do a relocation in which we convert a TLS General-Dynamic to an 4157 // Initial-Exec. 4158 4159 template<int size> 4160 inline void 4161 Target_x86_64<size>::Relocate::tls_gd_to_ie( 4162 const Relocate_info<size, false>* relinfo, 4163 size_t relnum, 4164 const elfcpp::Rela<size, false>& rela, 4165 unsigned int, 4166 typename elfcpp::Elf_types<size>::Elf_Addr value, 4167 unsigned char* view, 4168 typename elfcpp::Elf_types<size>::Elf_Addr address, 4169 section_size_type view_size) 4170 { 4171 // For SIZE == 64: 4172 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4173 // .word 0x6666; rex64; call __tls_get_addr@PLT 4174 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax 4175 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4176 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4177 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax 4178 // For SIZE == 32: 4179 // leaq foo@tlsgd(%rip),%rdi; 4180 // .word 0x6666; rex64; call __tls_get_addr@PLT 4181 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax 4182 // leaq foo@tlsgd(%rip),%rdi; 4183 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4184 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax 4185 4186 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); 4187 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4188 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0 4189 || memcmp(view + 4, "\x66\x48\xff", 3) == 0)); 4190 4191 if (size == 64) 4192 { 4193 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4194 -4); 4195 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4196 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); 4197 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 4198 16); 4199 } 4200 else 4201 { 4202 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4203 -3); 4204 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4205 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0)); 4206 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 4207 15); 4208 } 4209 4210 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 4211 Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8, 4212 address); 4213 4214 // The next reloc should be a PLT32 reloc against __tls_get_addr. 4215 // We can skip it. 4216 this->skip_call_tls_get_addr_ = true; 4217 } 4218 4219 // Do a relocation in which we convert a TLS General-Dynamic to a 4220 // Local-Exec. 4221 4222 template<int size> 4223 inline void 4224 Target_x86_64<size>::Relocate::tls_gd_to_le( 4225 const Relocate_info<size, false>* relinfo, 4226 size_t relnum, 4227 Output_segment* tls_segment, 4228 const elfcpp::Rela<size, false>& rela, 4229 unsigned int, 4230 typename elfcpp::Elf_types<size>::Elf_Addr value, 4231 unsigned char* view, 4232 section_size_type view_size) 4233 { 4234 // For SIZE == 64: 4235 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4236 // .word 0x6666; rex64; call __tls_get_addr@PLT 4237 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax 4238 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4239 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4240 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax 4241 // For SIZE == 32: 4242 // leaq foo@tlsgd(%rip),%rdi; 4243 // .word 0x6666; rex64; call __tls_get_addr@PLT 4244 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax 4245 // leaq foo@tlsgd(%rip),%rdi; 4246 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4247 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax 4248 4249 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); 4250 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4251 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0 4252 || memcmp(view + 4, "\x66\x48\xff", 3) == 0)); 4253 4254 if (size == 64) 4255 { 4256 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4257 -4); 4258 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4259 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); 4260 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 4261 16); 4262 } 4263 else 4264 { 4265 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4266 -3); 4267 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4268 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0)); 4269 4270 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 4271 15); 4272 } 4273 4274 value -= tls_segment->memsz(); 4275 Relocate_functions<size, false>::rela32(view + 8, value, 0); 4276 4277 // The next reloc should be a PLT32 reloc against __tls_get_addr. 4278 // We can skip it. 4279 this->skip_call_tls_get_addr_ = true; 4280 } 4281 4282 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. 4283 4284 template<int size> 4285 inline void 4286 Target_x86_64<size>::Relocate::tls_desc_gd_to_ie( 4287 const Relocate_info<size, false>* relinfo, 4288 size_t relnum, 4289 const elfcpp::Rela<size, false>& rela, 4290 unsigned int r_type, 4291 typename elfcpp::Elf_types<size>::Elf_Addr value, 4292 unsigned char* view, 4293 typename elfcpp::Elf_types<size>::Elf_Addr address, 4294 section_size_type view_size) 4295 { 4296 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) 4297 { 4298 // leaq foo@tlsdesc(%rip), %rax 4299 // ==> movq foo@gottpoff(%rip), %rax 4300 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 4301 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 4302 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4303 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); 4304 view[-2] = 0x8b; 4305 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 4306 Relocate_functions<size, false>::pcrela32(view, value, addend, address); 4307 } 4308 else 4309 { 4310 // call *foo@tlscall(%rax) 4311 // ==> nop; nop 4312 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); 4313 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); 4314 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4315 view[0] == 0xff && view[1] == 0x10); 4316 view[0] = 0x66; 4317 view[1] = 0x90; 4318 } 4319 } 4320 4321 // Do a TLSDESC-style General-Dynamic to Local-Exec transition. 4322 4323 template<int size> 4324 inline void 4325 Target_x86_64<size>::Relocate::tls_desc_gd_to_le( 4326 const Relocate_info<size, false>* relinfo, 4327 size_t relnum, 4328 Output_segment* tls_segment, 4329 const elfcpp::Rela<size, false>& rela, 4330 unsigned int r_type, 4331 typename elfcpp::Elf_types<size>::Elf_Addr value, 4332 unsigned char* view, 4333 section_size_type view_size) 4334 { 4335 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) 4336 { 4337 // leaq foo@tlsdesc(%rip), %rax 4338 // ==> movq foo@tpoff, %rax 4339 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 4340 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 4341 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4342 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); 4343 view[-2] = 0xc7; 4344 view[-1] = 0xc0; 4345 value -= tls_segment->memsz(); 4346 Relocate_functions<size, false>::rela32(view, value, 0); 4347 } 4348 else 4349 { 4350 // call *foo@tlscall(%rax) 4351 // ==> nop; nop 4352 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); 4353 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); 4354 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4355 view[0] == 0xff && view[1] == 0x10); 4356 view[0] = 0x66; 4357 view[1] = 0x90; 4358 } 4359 } 4360 4361 template<int size> 4362 inline void 4363 Target_x86_64<size>::Relocate::tls_ld_to_le( 4364 const Relocate_info<size, false>* relinfo, 4365 size_t relnum, 4366 Output_segment*, 4367 const elfcpp::Rela<size, false>& rela, 4368 unsigned int, 4369 typename elfcpp::Elf_types<size>::Elf_Addr, 4370 unsigned char* view, 4371 section_size_type view_size) 4372 { 4373 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; 4374 // For SIZE == 64: 4375 // ... leq foo@dtpoff(%rax),%reg 4376 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx 4377 // For SIZE == 32: 4378 // ... leq foo@dtpoff(%rax),%reg 4379 // ==> nopl 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx 4380 // leaq foo@tlsld(%rip),%rdi; call *__tls_get_addr@GOTPCREL(%rip) 4381 // For SIZE == 64: 4382 // ... leq foo@dtpoff(%rax),%reg 4383 // ==> .word 0x6666; .byte 0x6666; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx 4384 // For SIZE == 32: 4385 // ... leq foo@dtpoff(%rax),%reg 4386 // ==> nopw 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx 4387 4388 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 4389 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9); 4390 4391 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4392 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d); 4393 4394 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4395 view[4] == 0xe8 || view[4] == 0xff); 4396 4397 if (view[4] == 0xe8) 4398 { 4399 if (size == 64) 4400 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12); 4401 else 4402 memcpy(view - 3, "\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 12); 4403 } 4404 else 4405 { 4406 if (size == 64) 4407 memcpy(view - 3, "\x66\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 4408 13); 4409 else 4410 memcpy(view - 3, "\x66\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 4411 13); 4412 } 4413 4414 // The next reloc should be a PLT32 reloc against __tls_get_addr. 4415 // We can skip it. 4416 this->skip_call_tls_get_addr_ = true; 4417 } 4418 4419 // Do a relocation in which we convert a TLS Initial-Exec to a 4420 // Local-Exec. 4421 4422 template<int size> 4423 inline void 4424 Target_x86_64<size>::Relocate::tls_ie_to_le( 4425 const Relocate_info<size, false>* relinfo, 4426 size_t relnum, 4427 Output_segment* tls_segment, 4428 const elfcpp::Rela<size, false>& rela, 4429 unsigned int, 4430 typename elfcpp::Elf_types<size>::Elf_Addr value, 4431 unsigned char* view, 4432 section_size_type view_size) 4433 { 4434 // We need to examine the opcodes to figure out which instruction we 4435 // are looking at. 4436 4437 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg 4438 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg 4439 4440 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 4441 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 4442 4443 unsigned char op1 = view[-3]; 4444 unsigned char op2 = view[-2]; 4445 unsigned char op3 = view[-1]; 4446 unsigned char reg = op3 >> 3; 4447 4448 if (op2 == 0x8b) 4449 { 4450 // movq 4451 if (op1 == 0x4c) 4452 view[-3] = 0x49; 4453 else if (size == 32 && op1 == 0x44) 4454 view[-3] = 0x41; 4455 view[-2] = 0xc7; 4456 view[-1] = 0xc0 | reg; 4457 } 4458 else if (reg == 4) 4459 { 4460 // Special handling for %rsp. 4461 if (op1 == 0x4c) 4462 view[-3] = 0x49; 4463 else if (size == 32 && op1 == 0x44) 4464 view[-3] = 0x41; 4465 view[-2] = 0x81; 4466 view[-1] = 0xc0 | reg; 4467 } 4468 else 4469 { 4470 // addq 4471 if (op1 == 0x4c) 4472 view[-3] = 0x4d; 4473 else if (size == 32 && op1 == 0x44) 4474 view[-3] = 0x45; 4475 view[-2] = 0x8d; 4476 view[-1] = 0x80 | reg | (reg << 3); 4477 } 4478 4479 if (tls_segment != NULL) 4480 value -= tls_segment->memsz(); 4481 Relocate_functions<size, false>::rela32(view, value, 0); 4482 } 4483 4484 // Relocate section data. 4485 4486 template<int size> 4487 void 4488 Target_x86_64<size>::relocate_section( 4489 const Relocate_info<size, false>* relinfo, 4490 unsigned int sh_type, 4491 const unsigned char* prelocs, 4492 size_t reloc_count, 4493 Output_section* output_section, 4494 bool needs_special_offset_handling, 4495 unsigned char* view, 4496 typename elfcpp::Elf_types<size>::Elf_Addr address, 4497 section_size_type view_size, 4498 const Reloc_symbol_changes* reloc_symbol_changes) 4499 { 4500 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4501 Classify_reloc; 4502 4503 gold_assert(sh_type == elfcpp::SHT_RELA); 4504 4505 gold::relocate_section<size, false, Target_x86_64<size>, Relocate, 4506 gold::Default_comdat_behavior, Classify_reloc>( 4507 relinfo, 4508 this, 4509 prelocs, 4510 reloc_count, 4511 output_section, 4512 needs_special_offset_handling, 4513 view, 4514 address, 4515 view_size, 4516 reloc_symbol_changes); 4517 } 4518 4519 // Apply an incremental relocation. Incremental relocations always refer 4520 // to global symbols. 4521 4522 template<int size> 4523 void 4524 Target_x86_64<size>::apply_relocation( 4525 const Relocate_info<size, false>* relinfo, 4526 typename elfcpp::Elf_types<size>::Elf_Addr r_offset, 4527 unsigned int r_type, 4528 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, 4529 const Symbol* gsym, 4530 unsigned char* view, 4531 typename elfcpp::Elf_types<size>::Elf_Addr address, 4532 section_size_type view_size) 4533 { 4534 gold::apply_relocation<size, false, Target_x86_64<size>, 4535 typename Target_x86_64<size>::Relocate>( 4536 relinfo, 4537 this, 4538 r_offset, 4539 r_type, 4540 r_addend, 4541 gsym, 4542 view, 4543 address, 4544 view_size); 4545 } 4546 4547 // Scan the relocs during a relocatable link. 4548 4549 template<int size> 4550 void 4551 Target_x86_64<size>::scan_relocatable_relocs( 4552 Symbol_table* symtab, 4553 Layout* layout, 4554 Sized_relobj_file<size, false>* object, 4555 unsigned int data_shndx, 4556 unsigned int sh_type, 4557 const unsigned char* prelocs, 4558 size_t reloc_count, 4559 Output_section* output_section, 4560 bool needs_special_offset_handling, 4561 size_t local_symbol_count, 4562 const unsigned char* plocal_symbols, 4563 Relocatable_relocs* rr) 4564 { 4565 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4566 Classify_reloc; 4567 typedef gold::Default_scan_relocatable_relocs<Classify_reloc> 4568 Scan_relocatable_relocs; 4569 4570 gold_assert(sh_type == elfcpp::SHT_RELA); 4571 4572 gold::scan_relocatable_relocs<size, false, Scan_relocatable_relocs>( 4573 symtab, 4574 layout, 4575 object, 4576 data_shndx, 4577 prelocs, 4578 reloc_count, 4579 output_section, 4580 needs_special_offset_handling, 4581 local_symbol_count, 4582 plocal_symbols, 4583 rr); 4584 } 4585 4586 // Scan the relocs for --emit-relocs. 4587 4588 template<int size> 4589 void 4590 Target_x86_64<size>::emit_relocs_scan( 4591 Symbol_table* symtab, 4592 Layout* layout, 4593 Sized_relobj_file<size, false>* object, 4594 unsigned int data_shndx, 4595 unsigned int sh_type, 4596 const unsigned char* prelocs, 4597 size_t reloc_count, 4598 Output_section* output_section, 4599 bool needs_special_offset_handling, 4600 size_t local_symbol_count, 4601 const unsigned char* plocal_syms, 4602 Relocatable_relocs* rr) 4603 { 4604 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4605 Classify_reloc; 4606 typedef gold::Default_emit_relocs_strategy<Classify_reloc> 4607 Emit_relocs_strategy; 4608 4609 gold_assert(sh_type == elfcpp::SHT_RELA); 4610 4611 gold::scan_relocatable_relocs<size, false, Emit_relocs_strategy>( 4612 symtab, 4613 layout, 4614 object, 4615 data_shndx, 4616 prelocs, 4617 reloc_count, 4618 output_section, 4619 needs_special_offset_handling, 4620 local_symbol_count, 4621 plocal_syms, 4622 rr); 4623 } 4624 4625 // Relocate a section during a relocatable link. 4626 4627 template<int size> 4628 void 4629 Target_x86_64<size>::relocate_relocs( 4630 const Relocate_info<size, false>* relinfo, 4631 unsigned int sh_type, 4632 const unsigned char* prelocs, 4633 size_t reloc_count, 4634 Output_section* output_section, 4635 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, 4636 unsigned char* view, 4637 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 4638 section_size_type view_size, 4639 unsigned char* reloc_view, 4640 section_size_type reloc_view_size) 4641 { 4642 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4643 Classify_reloc; 4644 4645 gold_assert(sh_type == elfcpp::SHT_RELA); 4646 4647 gold::relocate_relocs<size, false, Classify_reloc>( 4648 relinfo, 4649 prelocs, 4650 reloc_count, 4651 output_section, 4652 offset_in_output_section, 4653 view, 4654 view_address, 4655 view_size, 4656 reloc_view, 4657 reloc_view_size); 4658 } 4659 4660 // Return the value to use for a dynamic which requires special 4661 // treatment. This is how we support equality comparisons of function 4662 // pointers across shared library boundaries, as described in the 4663 // processor specific ABI supplement. 4664 4665 template<int size> 4666 uint64_t 4667 Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const 4668 { 4669 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); 4670 return this->plt_address_for_global(gsym); 4671 } 4672 4673 // Return a string used to fill a code section with nops to take up 4674 // the specified length. 4675 4676 template<int size> 4677 std::string 4678 Target_x86_64<size>::do_code_fill(section_size_type length) const 4679 { 4680 if (length >= 16) 4681 { 4682 // Build a jmpq instruction to skip over the bytes. 4683 unsigned char jmp[5]; 4684 jmp[0] = 0xe9; 4685 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); 4686 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) 4687 + std::string(length - 5, static_cast<char>(0x90))); 4688 } 4689 4690 // Nop sequences of various lengths. 4691 const char nop1[1] = { '\x90' }; // nop 4692 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax 4693 const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax) 4694 const char nop4[4] = { '\x0f', '\x1f', '\x40', // nop 0(%rax) 4695 '\x00'}; 4696 const char nop5[5] = { '\x0f', '\x1f', '\x44', // nop 0(%rax,%rax,1) 4697 '\x00', '\x00' }; 4698 const char nop6[6] = { '\x66', '\x0f', '\x1f', // nopw 0(%rax,%rax,1) 4699 '\x44', '\x00', '\x00' }; 4700 const char nop7[7] = { '\x0f', '\x1f', '\x80', // nopl 0L(%rax) 4701 '\x00', '\x00', '\x00', 4702 '\x00' }; 4703 const char nop8[8] = { '\x0f', '\x1f', '\x84', // nopl 0L(%rax,%rax,1) 4704 '\x00', '\x00', '\x00', 4705 '\x00', '\x00' }; 4706 const char nop9[9] = { '\x66', '\x0f', '\x1f', // nopw 0L(%rax,%rax,1) 4707 '\x84', '\x00', '\x00', 4708 '\x00', '\x00', '\x00' }; 4709 const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1) 4710 '\x1f', '\x84', '\x00', 4711 '\x00', '\x00', '\x00', 4712 '\x00' }; 4713 const char nop11[11] = { '\x66', '\x66', '\x2e', // data16 4714 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1) 4715 '\x00', '\x00', '\x00', 4716 '\x00', '\x00' }; 4717 const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16 4718 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1) 4719 '\x84', '\x00', '\x00', 4720 '\x00', '\x00', '\x00' }; 4721 const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16 4722 '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1) 4723 '\x1f', '\x84', '\x00', 4724 '\x00', '\x00', '\x00', 4725 '\x00' }; 4726 const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16 4727 '\x66', '\x66', '\x2e', // data16 4728 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1) 4729 '\x00', '\x00', '\x00', 4730 '\x00', '\x00' }; 4731 const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16 4732 '\x66', '\x66', '\x66', // data16; data16 4733 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1) 4734 '\x84', '\x00', '\x00', 4735 '\x00', '\x00', '\x00' }; 4736 4737 const char* nops[16] = { 4738 NULL, 4739 nop1, nop2, nop3, nop4, nop5, nop6, nop7, 4740 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 4741 }; 4742 4743 return std::string(nops[length], length); 4744 } 4745 4746 // Return the addend to use for a target specific relocation. The 4747 // only target specific relocation is R_X86_64_TLSDESC for a local 4748 // symbol. We want to set the addend is the offset of the local 4749 // symbol in the TLS segment. 4750 4751 template<int size> 4752 uint64_t 4753 Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type, 4754 uint64_t) const 4755 { 4756 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); 4757 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg); 4758 gold_assert(intarg < this->tlsdesc_reloc_info_.size()); 4759 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]); 4760 const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym); 4761 gold_assert(psymval->is_tls_symbol()); 4762 // The value of a TLS symbol is the offset in the TLS segment. 4763 return psymval->value(ti.object, 0); 4764 } 4765 4766 // Return the value to use for the base of a DW_EH_PE_datarel offset 4767 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their 4768 // assembler can not write out the difference between two labels in 4769 // different sections, so instead of using a pc-relative value they 4770 // use an offset from the GOT. 4771 4772 template<int size> 4773 uint64_t 4774 Target_x86_64<size>::do_ehframe_datarel_base() const 4775 { 4776 gold_assert(this->global_offset_table_ != NULL); 4777 Symbol* sym = this->global_offset_table_; 4778 Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym); 4779 return ssym->value(); 4780 } 4781 4782 // FNOFFSET in section SHNDX in OBJECT is the start of a function 4783 // compiled with -fsplit-stack. The function calls non-split-stack 4784 // code. We have to change the function so that it always ensures 4785 // that it has enough stack space to run some random function. 4786 4787 static const unsigned char cmp_insn_32[] = { 0x64, 0x3b, 0x24, 0x25 }; 4788 static const unsigned char lea_r10_insn_32[] = { 0x44, 0x8d, 0x94, 0x24 }; 4789 static const unsigned char lea_r11_insn_32[] = { 0x44, 0x8d, 0x9c, 0x24 }; 4790 4791 static const unsigned char cmp_insn_64[] = { 0x64, 0x48, 0x3b, 0x24, 0x25 }; 4792 static const unsigned char lea_r10_insn_64[] = { 0x4c, 0x8d, 0x94, 0x24 }; 4793 static const unsigned char lea_r11_insn_64[] = { 0x4c, 0x8d, 0x9c, 0x24 }; 4794 4795 template<int size> 4796 void 4797 Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx, 4798 section_offset_type fnoffset, 4799 section_size_type fnsize, 4800 const unsigned char*, 4801 size_t, 4802 unsigned char* view, 4803 section_size_type view_size, 4804 std::string* from, 4805 std::string* to) const 4806 { 4807 const char* const cmp_insn = reinterpret_cast<const char*> 4808 (size == 32 ? cmp_insn_32 : cmp_insn_64); 4809 const char* const lea_r10_insn = reinterpret_cast<const char*> 4810 (size == 32 ? lea_r10_insn_32 : lea_r10_insn_64); 4811 const char* const lea_r11_insn = reinterpret_cast<const char*> 4812 (size == 32 ? lea_r11_insn_32 : lea_r11_insn_64); 4813 4814 const size_t cmp_insn_len = 4815 (size == 32 ? sizeof(cmp_insn_32) : sizeof(cmp_insn_64)); 4816 const size_t lea_r10_insn_len = 4817 (size == 32 ? sizeof(lea_r10_insn_32) : sizeof(lea_r10_insn_64)); 4818 const size_t lea_r11_insn_len = 4819 (size == 32 ? sizeof(lea_r11_insn_32) : sizeof(lea_r11_insn_64)); 4820 const size_t nop_len = (size == 32 ? 7 : 8); 4821 4822 // The function starts with a comparison of the stack pointer and a 4823 // field in the TCB. This is followed by a jump. 4824 4825 // cmp %fs:NN,%rsp 4826 if (this->match_view(view, view_size, fnoffset, cmp_insn, cmp_insn_len) 4827 && fnsize > nop_len + 1) 4828 { 4829 // We will call __morestack if the carry flag is set after this 4830 // comparison. We turn the comparison into an stc instruction 4831 // and some nops. 4832 view[fnoffset] = '\xf9'; 4833 this->set_view_to_nop(view, view_size, fnoffset + 1, nop_len); 4834 } 4835 // lea NN(%rsp),%r10 4836 // lea NN(%rsp),%r11 4837 else if ((this->match_view(view, view_size, fnoffset, 4838 lea_r10_insn, lea_r10_insn_len) 4839 || this->match_view(view, view_size, fnoffset, 4840 lea_r11_insn, lea_r11_insn_len)) 4841 && fnsize > 8) 4842 { 4843 // This is loading an offset from the stack pointer for a 4844 // comparison. The offset is negative, so we decrease the 4845 // offset by the amount of space we need for the stack. This 4846 // means we will avoid calling __morestack if there happens to 4847 // be plenty of space on the stack already. 4848 unsigned char* pval = view + fnoffset + 4; 4849 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); 4850 val -= parameters->options().split_stack_adjust_size(); 4851 elfcpp::Swap_unaligned<32, false>::writeval(pval, val); 4852 } 4853 else 4854 { 4855 if (!object->has_no_split_stack()) 4856 object->error(_("failed to match split-stack sequence at " 4857 "section %u offset %0zx"), 4858 shndx, static_cast<size_t>(fnoffset)); 4859 return; 4860 } 4861 4862 // We have to change the function so that it calls 4863 // __morestack_non_split instead of __morestack. The former will 4864 // allocate additional stack space. 4865 *from = "__morestack"; 4866 *to = "__morestack_non_split"; 4867 } 4868 4869 // The selector for x86_64 object files. Note this is never instantiated 4870 // directly. It's only used in Target_selector_x86_64_nacl, below. 4871 4872 template<int size> 4873 class Target_selector_x86_64 : public Target_selector_freebsd 4874 { 4875 public: 4876 Target_selector_x86_64() 4877 : Target_selector_freebsd(elfcpp::EM_X86_64, size, false, 4878 (size == 64 4879 ? "elf64-x86-64" : "elf32-x86-64"), 4880 (size == 64 4881 ? "elf64-x86-64-freebsd" 4882 : "elf32-x86-64-freebsd"), 4883 (size == 64 ? "elf_x86_64" : "elf32_x86_64")) 4884 { } 4885 4886 Target* 4887 do_instantiate_target() 4888 { return new Target_x86_64<size>(); } 4889 4890 }; 4891 4892 // NaCl variant. It uses different PLT contents. 4893 4894 template<int size> 4895 class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size> 4896 { 4897 public: 4898 Output_data_plt_x86_64_nacl(Layout* layout, 4899 Output_data_got<64, false>* got, 4900 Output_data_got_plt_x86_64* got_plt, 4901 Output_data_space* got_irelative) 4902 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 4903 got, got_plt, got_irelative) 4904 { } 4905 4906 Output_data_plt_x86_64_nacl(Layout* layout, 4907 Output_data_got<64, false>* got, 4908 Output_data_got_plt_x86_64* got_plt, 4909 Output_data_space* got_irelative, 4910 unsigned int plt_count) 4911 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 4912 got, got_plt, got_irelative, 4913 plt_count) 4914 { } 4915 4916 protected: 4917 virtual unsigned int 4918 do_get_plt_entry_size() const 4919 { return plt_entry_size; } 4920 4921 virtual void 4922 do_add_eh_frame(Layout* layout) 4923 { 4924 layout->add_eh_frame_for_plt(this, 4925 this->plt_eh_frame_cie, 4926 this->plt_eh_frame_cie_size, 4927 plt_eh_frame_fde, 4928 plt_eh_frame_fde_size); 4929 } 4930 4931 virtual void 4932 do_fill_first_plt_entry(unsigned char* pov, 4933 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 4934 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); 4935 4936 virtual unsigned int 4937 do_fill_plt_entry(unsigned char* pov, 4938 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 4939 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 4940 unsigned int got_offset, 4941 unsigned int plt_offset, 4942 unsigned int plt_index); 4943 4944 virtual void 4945 do_fill_tlsdesc_entry(unsigned char* pov, 4946 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 4947 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 4948 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 4949 unsigned int tlsdesc_got_offset, 4950 unsigned int plt_offset); 4951 4952 private: 4953 // The size of an entry in the PLT. 4954 static const int plt_entry_size = 64; 4955 4956 // The first entry in the PLT. 4957 static const unsigned char first_plt_entry[plt_entry_size]; 4958 4959 // Other entries in the PLT for an executable. 4960 static const unsigned char plt_entry[plt_entry_size]; 4961 4962 // The reserved TLSDESC entry in the PLT for an executable. 4963 static const unsigned char tlsdesc_plt_entry[plt_entry_size]; 4964 4965 // The .eh_frame unwind information for the PLT. 4966 static const int plt_eh_frame_fde_size = 32; 4967 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; 4968 }; 4969 4970 template<int size> 4971 class Target_x86_64_nacl : public Target_x86_64<size> 4972 { 4973 public: 4974 Target_x86_64_nacl() 4975 : Target_x86_64<size>(&x86_64_nacl_info) 4976 { } 4977 4978 virtual Output_data_plt_x86_64<size>* 4979 do_make_data_plt(Layout* layout, 4980 Output_data_got<64, false>* got, 4981 Output_data_got_plt_x86_64* got_plt, 4982 Output_data_space* got_irelative) 4983 { 4984 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt, 4985 got_irelative); 4986 } 4987 4988 virtual Output_data_plt_x86_64<size>* 4989 do_make_data_plt(Layout* layout, 4990 Output_data_got<64, false>* got, 4991 Output_data_got_plt_x86_64* got_plt, 4992 Output_data_space* got_irelative, 4993 unsigned int plt_count) 4994 { 4995 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt, 4996 got_irelative, 4997 plt_count); 4998 } 4999 5000 virtual std::string 5001 do_code_fill(section_size_type length) const; 5002 5003 private: 5004 static const Target::Target_info x86_64_nacl_info; 5005 }; 5006 5007 template<> 5008 const Target::Target_info Target_x86_64_nacl<64>::x86_64_nacl_info = 5009 { 5010 64, // size 5011 false, // is_big_endian 5012 elfcpp::EM_X86_64, // machine_code 5013 false, // has_make_symbol 5014 false, // has_resolve 5015 true, // has_code_fill 5016 true, // is_default_stack_executable 5017 true, // can_icf_inline_merge_sections 5018 '\0', // wrap_char 5019 "/lib64/ld-nacl-x86-64.so.1", // dynamic_linker 5020 0x20000, // default_text_segment_address 5021 0x10000, // abi_pagesize (overridable by -z max-page-size) 5022 0x10000, // common_pagesize (overridable by -z common-page-size) 5023 true, // isolate_execinstr 5024 0x10000000, // rosegment_gap 5025 elfcpp::SHN_UNDEF, // small_common_shndx 5026 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 5027 0, // small_common_section_flags 5028 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 5029 NULL, // attributes_section 5030 NULL, // attributes_vendor 5031 "_start", // entry_symbol_name 5032 32, // hash_entry_size 5033 }; 5034 5035 template<> 5036 const Target::Target_info Target_x86_64_nacl<32>::x86_64_nacl_info = 5037 { 5038 32, // size 5039 false, // is_big_endian 5040 elfcpp::EM_X86_64, // machine_code 5041 false, // has_make_symbol 5042 false, // has_resolve 5043 true, // has_code_fill 5044 true, // is_default_stack_executable 5045 true, // can_icf_inline_merge_sections 5046 '\0', // wrap_char 5047 "/lib/ld-nacl-x86-64.so.1", // dynamic_linker 5048 0x20000, // default_text_segment_address 5049 0x10000, // abi_pagesize (overridable by -z max-page-size) 5050 0x10000, // common_pagesize (overridable by -z common-page-size) 5051 true, // isolate_execinstr 5052 0x10000000, // rosegment_gap 5053 elfcpp::SHN_UNDEF, // small_common_shndx 5054 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 5055 0, // small_common_section_flags 5056 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 5057 NULL, // attributes_section 5058 NULL, // attributes_vendor 5059 "_start", // entry_symbol_name 5060 32, // hash_entry_size 5061 }; 5062 5063 #define NACLMASK 0xe0 // 32-byte alignment mask. 5064 5065 // The first entry in the PLT. 5066 5067 template<int size> 5068 const unsigned char 5069 Output_data_plt_x86_64_nacl<size>::first_plt_entry[plt_entry_size] = 5070 { 5071 0xff, 0x35, // pushq contents of memory address 5072 0, 0, 0, 0, // replaced with address of .got + 8 5073 0x4c, 0x8b, 0x1d, // mov GOT+16(%rip), %r11 5074 0, 0, 0, 0, // replaced with address of .got + 16 5075 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 5076 0x4d, 0x01, 0xfb, // add %r15, %r11 5077 0x41, 0xff, 0xe3, // jmpq *%r11 5078 5079 // 9-byte nop sequence to pad out to the next 32-byte boundary. 5080 0x66, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw 0x0(%rax,%rax,1) 5081 5082 // 32 bytes of nop to pad out to the standard size 5083 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5084 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5085 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5086 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5087 0x66, // excess data32 prefix 5088 0x90 // nop 5089 }; 5090 5091 template<int size> 5092 void 5093 Output_data_plt_x86_64_nacl<size>::do_fill_first_plt_entry( 5094 unsigned char* pov, 5095 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5096 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 5097 { 5098 memcpy(pov, first_plt_entry, plt_entry_size); 5099 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 5100 (got_address + 8 5101 - (plt_address + 2 + 4))); 5102 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9, 5103 (got_address + 16 5104 - (plt_address + 9 + 4))); 5105 } 5106 5107 // Subsequent entries in the PLT. 5108 5109 template<int size> 5110 const unsigned char 5111 Output_data_plt_x86_64_nacl<size>::plt_entry[plt_entry_size] = 5112 { 5113 0x4c, 0x8b, 0x1d, // mov name@GOTPCREL(%rip),%r11 5114 0, 0, 0, 0, // replaced with address of symbol in .got 5115 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 5116 0x4d, 0x01, 0xfb, // add %r15, %r11 5117 0x41, 0xff, 0xe3, // jmpq *%r11 5118 5119 // 15-byte nop sequence to pad out to the next 32-byte boundary. 5120 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5121 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5122 5123 // Lazy GOT entries point here (32-byte aligned). 5124 0x68, // pushq immediate 5125 0, 0, 0, 0, // replaced with index into relocation table 5126 0xe9, // jmp relative 5127 0, 0, 0, 0, // replaced with offset to start of .plt0 5128 5129 // 22 bytes of nop to pad out to the standard size. 5130 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5131 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5132 0x0f, 0x1f, 0x80, 0, 0, 0, 0, // nopl 0x0(%rax) 5133 }; 5134 5135 template<int size> 5136 unsigned int 5137 Output_data_plt_x86_64_nacl<size>::do_fill_plt_entry( 5138 unsigned char* pov, 5139 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5140 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 5141 unsigned int got_offset, 5142 unsigned int plt_offset, 5143 unsigned int plt_index) 5144 { 5145 memcpy(pov, plt_entry, plt_entry_size); 5146 elfcpp::Swap_unaligned<32, false>::writeval(pov + 3, 5147 (got_address + got_offset 5148 - (plt_address + plt_offset 5149 + 3 + 4))); 5150 5151 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_index); 5152 elfcpp::Swap_unaligned<32, false>::writeval(pov + 38, 5153 - (plt_offset + 38 + 4)); 5154 5155 return 32; 5156 } 5157 5158 // The reserved TLSDESC entry in the PLT. 5159 5160 template<int size> 5161 const unsigned char 5162 Output_data_plt_x86_64_nacl<size>::tlsdesc_plt_entry[plt_entry_size] = 5163 { 5164 0xff, 0x35, // pushq x(%rip) 5165 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) 5166 0x4c, 0x8b, 0x1d, // mov y(%rip),%r11 5167 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry 5168 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 5169 0x4d, 0x01, 0xfb, // add %r15, %r11 5170 0x41, 0xff, 0xe3, // jmpq *%r11 5171 5172 // 41 bytes of nop to pad out to the standard size. 5173 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5174 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5175 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5176 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5177 0x66, 0x66, // excess data32 prefixes 5178 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5179 }; 5180 5181 template<int size> 5182 void 5183 Output_data_plt_x86_64_nacl<size>::do_fill_tlsdesc_entry( 5184 unsigned char* pov, 5185 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5186 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 5187 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 5188 unsigned int tlsdesc_got_offset, 5189 unsigned int plt_offset) 5190 { 5191 memcpy(pov, tlsdesc_plt_entry, plt_entry_size); 5192 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 5193 (got_address + 8 5194 - (plt_address + plt_offset 5195 + 2 + 4))); 5196 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9, 5197 (got_base 5198 + tlsdesc_got_offset 5199 - (plt_address + plt_offset 5200 + 9 + 4))); 5201 } 5202 5203 // The .eh_frame unwind information for the PLT. 5204 5205 template<int size> 5206 const unsigned char 5207 Output_data_plt_x86_64_nacl<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = 5208 { 5209 0, 0, 0, 0, // Replaced with offset to .plt. 5210 0, 0, 0, 0, // Replaced with size of .plt. 5211 0, // Augmentation size. 5212 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. 5213 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. 5214 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. 5215 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64. 5216 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. 5217 13, // Block length. 5218 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. 5219 elfcpp::DW_OP_breg16, 0, // Push %rip. 5220 elfcpp::DW_OP_const1u, 63, // Push 0x3f. 5221 elfcpp::DW_OP_and, // & (%rip & 0x3f). 5222 elfcpp::DW_OP_const1u, 37, // Push 0x25. 5223 elfcpp::DW_OP_ge, // >= ((%rip & 0x3f) >= 0x25) 5224 elfcpp::DW_OP_lit3, // Push 3. 5225 elfcpp::DW_OP_shl, // << (((%rip & 0x3f) >= 0x25) << 3) 5226 elfcpp::DW_OP_plus, // + ((((%rip&0x3f)>=0x25)<<3)+%rsp+8 5227 elfcpp::DW_CFA_nop, // Align to 32 bytes. 5228 elfcpp::DW_CFA_nop 5229 }; 5230 5231 // Return a string used to fill a code section with nops. 5232 // For NaCl, long NOPs are only valid if they do not cross 5233 // bundle alignment boundaries, so keep it simple with one-byte NOPs. 5234 template<int size> 5235 std::string 5236 Target_x86_64_nacl<size>::do_code_fill(section_size_type length) const 5237 { 5238 return std::string(length, static_cast<char>(0x90)); 5239 } 5240 5241 // The selector for x86_64-nacl object files. 5242 5243 template<int size> 5244 class Target_selector_x86_64_nacl 5245 : public Target_selector_nacl<Target_selector_x86_64<size>, 5246 Target_x86_64_nacl<size> > 5247 { 5248 public: 5249 Target_selector_x86_64_nacl() 5250 : Target_selector_nacl<Target_selector_x86_64<size>, 5251 Target_x86_64_nacl<size> >("x86-64", 5252 size == 64 5253 ? "elf64-x86-64-nacl" 5254 : "elf32-x86-64-nacl", 5255 size == 64 5256 ? "elf_x86_64_nacl" 5257 : "elf32_x86_64_nacl") 5258 { } 5259 }; 5260 5261 Target_selector_x86_64_nacl<64> target_selector_x86_64; 5262 Target_selector_x86_64_nacl<32> target_selector_x32; 5263 5264 } // End anonymous namespace. 5265