1 // layout.cc -- lay out output file sections 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 <cerrno> 26 #include <cstring> 27 #include <algorithm> 28 #include <iostream> 29 #include <fstream> 30 #include <utility> 31 #include <fcntl.h> 32 #include <fnmatch.h> 33 #include <unistd.h> 34 #include "libiberty.h" 35 #include "md5.h" 36 #include "sha1.h" 37 38 #include "parameters.h" 39 #include "options.h" 40 #include "mapfile.h" 41 #include "script.h" 42 #include "script-sections.h" 43 #include "output.h" 44 #include "symtab.h" 45 #include "dynobj.h" 46 #include "ehframe.h" 47 #include "gdb-index.h" 48 #include "compressed_output.h" 49 #include "reduced_debug_output.h" 50 #include "object.h" 51 #include "reloc.h" 52 #include "descriptors.h" 53 #include "plugin.h" 54 #include "incremental.h" 55 #include "layout.h" 56 57 namespace gold 58 { 59 60 // Class Free_list. 61 62 // The total number of free lists used. 63 unsigned int Free_list::num_lists = 0; 64 // The total number of free list nodes used. 65 unsigned int Free_list::num_nodes = 0; 66 // The total number of calls to Free_list::remove. 67 unsigned int Free_list::num_removes = 0; 68 // The total number of nodes visited during calls to Free_list::remove. 69 unsigned int Free_list::num_remove_visits = 0; 70 // The total number of calls to Free_list::allocate. 71 unsigned int Free_list::num_allocates = 0; 72 // The total number of nodes visited during calls to Free_list::allocate. 73 unsigned int Free_list::num_allocate_visits = 0; 74 75 // Initialize the free list. Creates a single free list node that 76 // describes the entire region of length LEN. If EXTEND is true, 77 // allocate() is allowed to extend the region beyond its initial 78 // length. 79 80 void 81 Free_list::init(off_t len, bool extend) 82 { 83 this->list_.push_front(Free_list_node(0, len)); 84 this->last_remove_ = this->list_.begin(); 85 this->extend_ = extend; 86 this->length_ = len; 87 ++Free_list::num_lists; 88 ++Free_list::num_nodes; 89 } 90 91 // Remove a chunk from the free list. Because we start with a single 92 // node that covers the entire section, and remove chunks from it one 93 // at a time, we do not need to coalesce chunks or handle cases that 94 // span more than one free node. We expect to remove chunks from the 95 // free list in order, and we expect to have only a few chunks of free 96 // space left (corresponding to files that have changed since the last 97 // incremental link), so a simple linear list should provide sufficient 98 // performance. 99 100 void 101 Free_list::remove(off_t start, off_t end) 102 { 103 if (start == end) 104 return; 105 gold_assert(start < end); 106 107 ++Free_list::num_removes; 108 109 Iterator p = this->last_remove_; 110 if (p->start_ > start) 111 p = this->list_.begin(); 112 113 for (; p != this->list_.end(); ++p) 114 { 115 ++Free_list::num_remove_visits; 116 // Find a node that wholly contains the indicated region. 117 if (p->start_ <= start && p->end_ >= end) 118 { 119 // Case 1: the indicated region spans the whole node. 120 // Add some fuzz to avoid creating tiny free chunks. 121 if (p->start_ + 3 >= start && p->end_ <= end + 3) 122 p = this->list_.erase(p); 123 // Case 2: remove a chunk from the start of the node. 124 else if (p->start_ + 3 >= start) 125 p->start_ = end; 126 // Case 3: remove a chunk from the end of the node. 127 else if (p->end_ <= end + 3) 128 p->end_ = start; 129 // Case 4: remove a chunk from the middle, and split 130 // the node into two. 131 else 132 { 133 Free_list_node newnode(p->start_, start); 134 p->start_ = end; 135 this->list_.insert(p, newnode); 136 ++Free_list::num_nodes; 137 } 138 this->last_remove_ = p; 139 return; 140 } 141 } 142 143 // Did not find a node containing the given chunk. This could happen 144 // because a small chunk was already removed due to the fuzz. 145 gold_debug(DEBUG_INCREMENTAL, 146 "Free_list::remove(%d,%d) not found", 147 static_cast<int>(start), static_cast<int>(end)); 148 } 149 150 // Allocate a chunk of size LEN from the free list. Returns -1ULL 151 // if a sufficiently large chunk of free space is not found. 152 // We use a simple first-fit algorithm. 153 154 off_t 155 Free_list::allocate(off_t len, uint64_t align, off_t minoff) 156 { 157 gold_debug(DEBUG_INCREMENTAL, 158 "Free_list::allocate(%08lx, %d, %08lx)", 159 static_cast<long>(len), static_cast<int>(align), 160 static_cast<long>(minoff)); 161 if (len == 0) 162 return align_address(minoff, align); 163 164 ++Free_list::num_allocates; 165 166 // We usually want to drop free chunks smaller than 4 bytes. 167 // If we need to guarantee a minimum hole size, though, we need 168 // to keep track of all free chunks. 169 const int fuzz = this->min_hole_ > 0 ? 0 : 3; 170 171 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) 172 { 173 ++Free_list::num_allocate_visits; 174 off_t start = p->start_ > minoff ? p->start_ : minoff; 175 start = align_address(start, align); 176 off_t end = start + len; 177 if (end > p->end_ && p->end_ == this->length_ && this->extend_) 178 { 179 this->length_ = end; 180 p->end_ = end; 181 } 182 if (end == p->end_ || (end <= p->end_ - this->min_hole_)) 183 { 184 if (p->start_ + fuzz >= start && p->end_ <= end + fuzz) 185 this->list_.erase(p); 186 else if (p->start_ + fuzz >= start) 187 p->start_ = end; 188 else if (p->end_ <= end + fuzz) 189 p->end_ = start; 190 else 191 { 192 Free_list_node newnode(p->start_, start); 193 p->start_ = end; 194 this->list_.insert(p, newnode); 195 ++Free_list::num_nodes; 196 } 197 return start; 198 } 199 } 200 if (this->extend_) 201 { 202 off_t start = align_address(this->length_, align); 203 this->length_ = start + len; 204 return start; 205 } 206 return -1; 207 } 208 209 // Dump the free list (for debugging). 210 void 211 Free_list::dump() 212 { 213 gold_info("Free list:\n start end length\n"); 214 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) 215 gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_), 216 static_cast<long>(p->end_), 217 static_cast<long>(p->end_ - p->start_)); 218 } 219 220 // Print the statistics for the free lists. 221 void 222 Free_list::print_stats() 223 { 224 fprintf(stderr, _("%s: total free lists: %u\n"), 225 program_name, Free_list::num_lists); 226 fprintf(stderr, _("%s: total free list nodes: %u\n"), 227 program_name, Free_list::num_nodes); 228 fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"), 229 program_name, Free_list::num_removes); 230 fprintf(stderr, _("%s: nodes visited: %u\n"), 231 program_name, Free_list::num_remove_visits); 232 fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"), 233 program_name, Free_list::num_allocates); 234 fprintf(stderr, _("%s: nodes visited: %u\n"), 235 program_name, Free_list::num_allocate_visits); 236 } 237 238 // A Hash_task computes the MD5 checksum of an array of char. 239 240 class Hash_task : public Task 241 { 242 public: 243 Hash_task(Output_file* of, 244 size_t offset, 245 size_t size, 246 unsigned char* dst, 247 Task_token* final_blocker) 248 : of_(of), offset_(offset), size_(size), dst_(dst), 249 final_blocker_(final_blocker) 250 { } 251 252 void 253 run(Workqueue*) 254 { 255 const unsigned char* iv = 256 this->of_->get_input_view(this->offset_, this->size_); 257 md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_); 258 this->of_->free_input_view(this->offset_, this->size_, iv); 259 } 260 261 Task_token* 262 is_runnable() 263 { return NULL; } 264 265 // Unblock FINAL_BLOCKER_ when done. 266 void 267 locks(Task_locker* tl) 268 { tl->add(this, this->final_blocker_); } 269 270 std::string 271 get_name() const 272 { return "Hash_task"; } 273 274 private: 275 Output_file* of_; 276 const size_t offset_; 277 const size_t size_; 278 unsigned char* const dst_; 279 Task_token* const final_blocker_; 280 }; 281 282 // Layout::Relaxation_debug_check methods. 283 284 // Check that sections and special data are in reset states. 285 // We do not save states for Output_sections and special Output_data. 286 // So we check that they have not assigned any addresses or offsets. 287 // clean_up_after_relaxation simply resets their addresses and offsets. 288 void 289 Layout::Relaxation_debug_check::check_output_data_for_reset_values( 290 const Layout::Section_list& sections, 291 const Layout::Data_list& special_outputs, 292 const Layout::Data_list& relax_outputs) 293 { 294 for(Layout::Section_list::const_iterator p = sections.begin(); 295 p != sections.end(); 296 ++p) 297 gold_assert((*p)->address_and_file_offset_have_reset_values()); 298 299 for(Layout::Data_list::const_iterator p = special_outputs.begin(); 300 p != special_outputs.end(); 301 ++p) 302 gold_assert((*p)->address_and_file_offset_have_reset_values()); 303 304 gold_assert(relax_outputs.empty()); 305 } 306 307 // Save information of SECTIONS for checking later. 308 309 void 310 Layout::Relaxation_debug_check::read_sections( 311 const Layout::Section_list& sections) 312 { 313 for(Layout::Section_list::const_iterator p = sections.begin(); 314 p != sections.end(); 315 ++p) 316 { 317 Output_section* os = *p; 318 Section_info info; 319 info.output_section = os; 320 info.address = os->is_address_valid() ? os->address() : 0; 321 info.data_size = os->is_data_size_valid() ? os->data_size() : -1; 322 info.offset = os->is_offset_valid()? os->offset() : -1 ; 323 this->section_infos_.push_back(info); 324 } 325 } 326 327 // Verify SECTIONS using previously recorded information. 328 329 void 330 Layout::Relaxation_debug_check::verify_sections( 331 const Layout::Section_list& sections) 332 { 333 size_t i = 0; 334 for(Layout::Section_list::const_iterator p = sections.begin(); 335 p != sections.end(); 336 ++p, ++i) 337 { 338 Output_section* os = *p; 339 uint64_t address = os->is_address_valid() ? os->address() : 0; 340 off_t data_size = os->is_data_size_valid() ? os->data_size() : -1; 341 off_t offset = os->is_offset_valid()? os->offset() : -1 ; 342 343 if (i >= this->section_infos_.size()) 344 { 345 gold_fatal("Section_info of %s missing.\n", os->name()); 346 } 347 const Section_info& info = this->section_infos_[i]; 348 if (os != info.output_section) 349 gold_fatal("Section order changed. Expecting %s but see %s\n", 350 info.output_section->name(), os->name()); 351 if (address != info.address 352 || data_size != info.data_size 353 || offset != info.offset) 354 gold_fatal("Section %s changed.\n", os->name()); 355 } 356 } 357 358 // Layout_task_runner methods. 359 360 // Lay out the sections. This is called after all the input objects 361 // have been read. 362 363 void 364 Layout_task_runner::run(Workqueue* workqueue, const Task* task) 365 { 366 // See if any of the input definitions violate the One Definition Rule. 367 // TODO: if this is too slow, do this as a task, rather than inline. 368 this->symtab_->detect_odr_violations(task, this->options_.output_file_name()); 369 370 Layout* layout = this->layout_; 371 off_t file_size = layout->finalize(this->input_objects_, 372 this->symtab_, 373 this->target_, 374 task); 375 376 // Now we know the final size of the output file and we know where 377 // each piece of information goes. 378 379 if (this->mapfile_ != NULL) 380 { 381 this->mapfile_->print_discarded_sections(this->input_objects_); 382 layout->print_to_mapfile(this->mapfile_); 383 } 384 385 Output_file* of; 386 if (layout->incremental_base() == NULL) 387 { 388 of = new Output_file(parameters->options().output_file_name()); 389 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF) 390 of->set_is_temporary(); 391 of->open(file_size); 392 } 393 else 394 { 395 of = layout->incremental_base()->output_file(); 396 397 // Apply the incremental relocations for symbols whose values 398 // have changed. We do this before we resize the file and start 399 // writing anything else to it, so that we can read the old 400 // incremental information from the file before (possibly) 401 // overwriting it. 402 if (parameters->incremental_update()) 403 layout->incremental_base()->apply_incremental_relocs(this->symtab_, 404 this->layout_, 405 of); 406 407 of->resize(file_size); 408 } 409 410 // Queue up the final set of tasks. 411 gold::queue_final_tasks(this->options_, this->input_objects_, 412 this->symtab_, layout, workqueue, of); 413 } 414 415 // Layout methods. 416 417 Layout::Layout(int number_of_input_files, Script_options* script_options) 418 : number_of_input_files_(number_of_input_files), 419 script_options_(script_options), 420 namepool_(), 421 sympool_(), 422 dynpool_(), 423 signatures_(), 424 section_name_map_(), 425 segment_list_(), 426 section_list_(), 427 unattached_section_list_(), 428 special_output_list_(), 429 relax_output_list_(), 430 section_headers_(NULL), 431 tls_segment_(NULL), 432 relro_segment_(NULL), 433 interp_segment_(NULL), 434 increase_relro_(0), 435 symtab_section_(NULL), 436 symtab_xindex_(NULL), 437 dynsym_section_(NULL), 438 dynsym_xindex_(NULL), 439 dynamic_section_(NULL), 440 dynamic_symbol_(NULL), 441 dynamic_data_(NULL), 442 eh_frame_section_(NULL), 443 eh_frame_data_(NULL), 444 added_eh_frame_data_(false), 445 eh_frame_hdr_section_(NULL), 446 gdb_index_data_(NULL), 447 build_id_note_(NULL), 448 debug_abbrev_(NULL), 449 debug_info_(NULL), 450 group_signatures_(), 451 output_file_size_(-1), 452 have_added_input_section_(false), 453 sections_are_attached_(false), 454 input_requires_executable_stack_(false), 455 input_with_gnu_stack_note_(false), 456 input_without_gnu_stack_note_(false), 457 has_static_tls_(false), 458 any_postprocessing_sections_(false), 459 resized_signatures_(false), 460 have_stabstr_section_(false), 461 section_ordering_specified_(false), 462 unique_segment_for_sections_specified_(false), 463 incremental_inputs_(NULL), 464 record_output_section_data_from_script_(false), 465 script_output_section_data_list_(), 466 segment_states_(NULL), 467 relaxation_debug_check_(NULL), 468 section_order_map_(), 469 section_segment_map_(), 470 input_section_position_(), 471 input_section_glob_(), 472 incremental_base_(NULL), 473 free_list_() 474 { 475 // Make space for more than enough segments for a typical file. 476 // This is just for efficiency--it's OK if we wind up needing more. 477 this->segment_list_.reserve(12); 478 479 // We expect two unattached Output_data objects: the file header and 480 // the segment headers. 481 this->special_output_list_.reserve(2); 482 483 // Initialize structure needed for an incremental build. 484 if (parameters->incremental()) 485 this->incremental_inputs_ = new Incremental_inputs; 486 487 // The section name pool is worth optimizing in all cases, because 488 // it is small, but there are often overlaps due to .rel sections. 489 this->namepool_.set_optimize(); 490 } 491 492 // For incremental links, record the base file to be modified. 493 494 void 495 Layout::set_incremental_base(Incremental_binary* base) 496 { 497 this->incremental_base_ = base; 498 this->free_list_.init(base->output_file()->filesize(), true); 499 } 500 501 // Hash a key we use to look up an output section mapping. 502 503 size_t 504 Layout::Hash_key::operator()(const Layout::Key& k) const 505 { 506 return k.first + k.second.first + k.second.second; 507 } 508 509 // These are the debug sections that are actually used by gdb. 510 // Currently, we've checked versions of gdb up to and including 7.4. 511 // We only check the part of the name that follows ".debug_" or 512 // ".zdebug_". 513 514 static const char* gdb_sections[] = 515 { 516 "abbrev", 517 "addr", // Fission extension 518 // "aranges", // not used by gdb as of 7.4 519 "frame", 520 "gdb_scripts", 521 "info", 522 "types", 523 "line", 524 "loc", 525 "macinfo", 526 "macro", 527 // "pubnames", // not used by gdb as of 7.4 528 // "pubtypes", // not used by gdb as of 7.4 529 // "gnu_pubnames", // Fission extension 530 // "gnu_pubtypes", // Fission extension 531 "ranges", 532 "str", 533 "str_offsets", 534 }; 535 536 // This is the minimum set of sections needed for line numbers. 537 538 static const char* lines_only_debug_sections[] = 539 { 540 "abbrev", 541 // "addr", // Fission extension 542 // "aranges", // not used by gdb as of 7.4 543 // "frame", 544 // "gdb_scripts", 545 "info", 546 // "types", 547 "line", 548 // "loc", 549 // "macinfo", 550 // "macro", 551 // "pubnames", // not used by gdb as of 7.4 552 // "pubtypes", // not used by gdb as of 7.4 553 // "gnu_pubnames", // Fission extension 554 // "gnu_pubtypes", // Fission extension 555 // "ranges", 556 "str", 557 "str_offsets", // Fission extension 558 }; 559 560 // These sections are the DWARF fast-lookup tables, and are not needed 561 // when building a .gdb_index section. 562 563 static const char* gdb_fast_lookup_sections[] = 564 { 565 "aranges", 566 "pubnames", 567 "gnu_pubnames", 568 "pubtypes", 569 "gnu_pubtypes", 570 }; 571 572 // Returns whether the given debug section is in the list of 573 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the 574 // portion of the name following ".debug_" or ".zdebug_". 575 576 static inline bool 577 is_gdb_debug_section(const char* suffix) 578 { 579 // We can do this faster: binary search or a hashtable. But why bother? 580 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i) 581 if (strcmp(suffix, gdb_sections[i]) == 0) 582 return true; 583 return false; 584 } 585 586 // Returns whether the given section is needed for lines-only debugging. 587 588 static inline bool 589 is_lines_only_debug_section(const char* suffix) 590 { 591 // We can do this faster: binary search or a hashtable. But why bother? 592 for (size_t i = 0; 593 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections); 594 ++i) 595 if (strcmp(suffix, lines_only_debug_sections[i]) == 0) 596 return true; 597 return false; 598 } 599 600 // Returns whether the given section is a fast-lookup section that 601 // will not be needed when building a .gdb_index section. 602 603 static inline bool 604 is_gdb_fast_lookup_section(const char* suffix) 605 { 606 // We can do this faster: binary search or a hashtable. But why bother? 607 for (size_t i = 0; 608 i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections); 609 ++i) 610 if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0) 611 return true; 612 return false; 613 } 614 615 // Sometimes we compress sections. This is typically done for 616 // sections that are not part of normal program execution (such as 617 // .debug_* sections), and where the readers of these sections know 618 // how to deal with compressed sections. This routine doesn't say for 619 // certain whether we'll compress -- it depends on commandline options 620 // as well -- just whether this section is a candidate for compression. 621 // (The Output_compressed_section class decides whether to compress 622 // a given section, and picks the name of the compressed section.) 623 624 static bool 625 is_compressible_debug_section(const char* secname) 626 { 627 return (is_prefix_of(".debug", secname)); 628 } 629 630 // We may see compressed debug sections in input files. Return TRUE 631 // if this is the name of a compressed debug section. 632 633 bool 634 is_compressed_debug_section(const char* secname) 635 { 636 return (is_prefix_of(".zdebug", secname)); 637 } 638 639 std::string 640 corresponding_uncompressed_section_name(std::string secname) 641 { 642 gold_assert(secname[0] == '.' && secname[1] == 'z'); 643 std::string ret("."); 644 ret.append(secname, 2, std::string::npos); 645 return ret; 646 } 647 648 // Whether to include this section in the link. 649 650 template<int size, bool big_endian> 651 bool 652 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name, 653 const elfcpp::Shdr<size, big_endian>& shdr) 654 { 655 if (!parameters->options().relocatable() 656 && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)) 657 return false; 658 659 elfcpp::Elf_Word sh_type = shdr.get_sh_type(); 660 661 if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS) 662 || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC)) 663 return parameters->target().should_include_section(sh_type); 664 665 switch (sh_type) 666 { 667 case elfcpp::SHT_NULL: 668 case elfcpp::SHT_SYMTAB: 669 case elfcpp::SHT_DYNSYM: 670 case elfcpp::SHT_HASH: 671 case elfcpp::SHT_DYNAMIC: 672 case elfcpp::SHT_SYMTAB_SHNDX: 673 return false; 674 675 case elfcpp::SHT_STRTAB: 676 // Discard the sections which have special meanings in the ELF 677 // ABI. Keep others (e.g., .stabstr). We could also do this by 678 // checking the sh_link fields of the appropriate sections. 679 return (strcmp(name, ".dynstr") != 0 680 && strcmp(name, ".strtab") != 0 681 && strcmp(name, ".shstrtab") != 0); 682 683 case elfcpp::SHT_RELA: 684 case elfcpp::SHT_REL: 685 case elfcpp::SHT_GROUP: 686 // If we are emitting relocations these should be handled 687 // elsewhere. 688 gold_assert(!parameters->options().relocatable()); 689 return false; 690 691 case elfcpp::SHT_PROGBITS: 692 if (parameters->options().strip_debug() 693 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) 694 { 695 if (is_debug_info_section(name)) 696 return false; 697 } 698 if (parameters->options().strip_debug_non_line() 699 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) 700 { 701 // Debugging sections can only be recognized by name. 702 if (is_prefix_of(".debug_", name) 703 && !is_lines_only_debug_section(name + 7)) 704 return false; 705 if (is_prefix_of(".zdebug_", name) 706 && !is_lines_only_debug_section(name + 8)) 707 return false; 708 } 709 if (parameters->options().strip_debug_gdb() 710 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) 711 { 712 // Debugging sections can only be recognized by name. 713 if (is_prefix_of(".debug_", name) 714 && !is_gdb_debug_section(name + 7)) 715 return false; 716 if (is_prefix_of(".zdebug_", name) 717 && !is_gdb_debug_section(name + 8)) 718 return false; 719 } 720 if (parameters->options().gdb_index() 721 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) 722 { 723 // When building .gdb_index, we can strip .debug_pubnames, 724 // .debug_pubtypes, and .debug_aranges sections. 725 if (is_prefix_of(".debug_", name) 726 && is_gdb_fast_lookup_section(name + 7)) 727 return false; 728 if (is_prefix_of(".zdebug_", name) 729 && is_gdb_fast_lookup_section(name + 8)) 730 return false; 731 } 732 if (parameters->options().strip_lto_sections() 733 && !parameters->options().relocatable() 734 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) 735 { 736 // Ignore LTO sections containing intermediate code. 737 if (is_prefix_of(".gnu.lto_", name)) 738 return false; 739 } 740 // The GNU linker strips .gnu_debuglink sections, so we do too. 741 // This is a feature used to keep debugging information in 742 // separate files. 743 if (strcmp(name, ".gnu_debuglink") == 0) 744 return false; 745 return true; 746 747 default: 748 return true; 749 } 750 } 751 752 // Return an output section named NAME, or NULL if there is none. 753 754 Output_section* 755 Layout::find_output_section(const char* name) const 756 { 757 for (Section_list::const_iterator p = this->section_list_.begin(); 758 p != this->section_list_.end(); 759 ++p) 760 if (strcmp((*p)->name(), name) == 0) 761 return *p; 762 return NULL; 763 } 764 765 // Return an output segment of type TYPE, with segment flags SET set 766 // and segment flags CLEAR clear. Return NULL if there is none. 767 768 Output_segment* 769 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, 770 elfcpp::Elf_Word clear) const 771 { 772 for (Segment_list::const_iterator p = this->segment_list_.begin(); 773 p != this->segment_list_.end(); 774 ++p) 775 if (static_cast<elfcpp::PT>((*p)->type()) == type 776 && ((*p)->flags() & set) == set 777 && ((*p)->flags() & clear) == 0) 778 return *p; 779 return NULL; 780 } 781 782 // When we put a .ctors or .dtors section with more than one word into 783 // a .init_array or .fini_array section, we need to reverse the words 784 // in the .ctors/.dtors section. This is because .init_array executes 785 // constructors front to back, where .ctors executes them back to 786 // front, and vice-versa for .fini_array/.dtors. Although we do want 787 // to remap .ctors/.dtors into .init_array/.fini_array because it can 788 // be more efficient, we don't want to change the order in which 789 // constructors/destructors are run. This set just keeps track of 790 // these sections which need to be reversed. It is only changed by 791 // Layout::layout. It should be a private member of Layout, but that 792 // would require layout.h to #include object.h to get the definition 793 // of Section_id. 794 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array; 795 796 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a 797 // .init_array/.fini_array section. 798 799 bool 800 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const 801 { 802 return (ctors_sections_in_init_array.find(Section_id(relobj, shndx)) 803 != ctors_sections_in_init_array.end()); 804 } 805 806 // Return the output section to use for section NAME with type TYPE 807 // and section flags FLAGS. NAME must be canonicalized in the string 808 // pool, and NAME_KEY is the key. ORDER is where this should appear 809 // in the output sections. IS_RELRO is true for a relro section. 810 811 Output_section* 812 Layout::get_output_section(const char* name, Stringpool::Key name_key, 813 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, 814 Output_section_order order, bool is_relro) 815 { 816 elfcpp::Elf_Word lookup_type = type; 817 818 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and 819 // PREINIT_ARRAY like PROGBITS. This ensures that we combine 820 // .init_array, .fini_array, and .preinit_array sections by name 821 // whatever their type in the input file. We do this because the 822 // types are not always right in the input files. 823 if (lookup_type == elfcpp::SHT_INIT_ARRAY 824 || lookup_type == elfcpp::SHT_FINI_ARRAY 825 || lookup_type == elfcpp::SHT_PREINIT_ARRAY) 826 lookup_type = elfcpp::SHT_PROGBITS; 827 828 elfcpp::Elf_Xword lookup_flags = flags; 829 830 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine 831 // read-write with read-only sections. Some other ELF linkers do 832 // not do this. FIXME: Perhaps there should be an option 833 // controlling this. 834 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); 835 836 const Key key(name_key, std::make_pair(lookup_type, lookup_flags)); 837 const std::pair<Key, Output_section*> v(key, NULL); 838 std::pair<Section_name_map::iterator, bool> ins( 839 this->section_name_map_.insert(v)); 840 841 if (!ins.second) 842 return ins.first->second; 843 else 844 { 845 // This is the first time we've seen this name/type/flags 846 // combination. For compatibility with the GNU linker, we 847 // combine sections with contents and zero flags with sections 848 // with non-zero flags. This is a workaround for cases where 849 // assembler code forgets to set section flags. FIXME: Perhaps 850 // there should be an option to control this. 851 Output_section* os = NULL; 852 853 if (lookup_type == elfcpp::SHT_PROGBITS) 854 { 855 if (flags == 0) 856 { 857 Output_section* same_name = this->find_output_section(name); 858 if (same_name != NULL 859 && (same_name->type() == elfcpp::SHT_PROGBITS 860 || same_name->type() == elfcpp::SHT_INIT_ARRAY 861 || same_name->type() == elfcpp::SHT_FINI_ARRAY 862 || same_name->type() == elfcpp::SHT_PREINIT_ARRAY) 863 && (same_name->flags() & elfcpp::SHF_TLS) == 0) 864 os = same_name; 865 } 866 else if ((flags & elfcpp::SHF_TLS) == 0) 867 { 868 elfcpp::Elf_Xword zero_flags = 0; 869 const Key zero_key(name_key, std::make_pair(lookup_type, 870 zero_flags)); 871 Section_name_map::iterator p = 872 this->section_name_map_.find(zero_key); 873 if (p != this->section_name_map_.end()) 874 os = p->second; 875 } 876 } 877 878 if (os == NULL) 879 os = this->make_output_section(name, type, flags, order, is_relro); 880 881 ins.first->second = os; 882 return os; 883 } 884 } 885 886 // Returns TRUE iff NAME (an input section from RELOBJ) will 887 // be mapped to an output section that should be KEPT. 888 889 bool 890 Layout::keep_input_section(const Relobj* relobj, const char* name) 891 { 892 if (! this->script_options_->saw_sections_clause()) 893 return false; 894 895 Script_sections* ss = this->script_options_->script_sections(); 896 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); 897 Output_section** output_section_slot; 898 Script_sections::Section_type script_section_type; 899 bool keep; 900 901 name = ss->output_section_name(file_name, name, &output_section_slot, 902 &script_section_type, &keep); 903 return name != NULL && keep; 904 } 905 906 // Clear the input section flags that should not be copied to the 907 // output section. 908 909 elfcpp::Elf_Xword 910 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags) 911 { 912 // Some flags in the input section should not be automatically 913 // copied to the output section. 914 input_section_flags &= ~ (elfcpp::SHF_INFO_LINK 915 | elfcpp::SHF_GROUP 916 | elfcpp::SHF_COMPRESSED 917 | elfcpp::SHF_MERGE 918 | elfcpp::SHF_STRINGS); 919 920 // We only clear the SHF_LINK_ORDER flag in for 921 // a non-relocatable link. 922 if (!parameters->options().relocatable()) 923 input_section_flags &= ~elfcpp::SHF_LINK_ORDER; 924 925 return input_section_flags; 926 } 927 928 // Pick the output section to use for section NAME, in input file 929 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a 930 // linker created section. IS_INPUT_SECTION is true if we are 931 // choosing an output section for an input section found in a input 932 // file. ORDER is where this section should appear in the output 933 // sections. IS_RELRO is true for a relro section. This will return 934 // NULL if the input section should be discarded. 935 936 Output_section* 937 Layout::choose_output_section(const Relobj* relobj, const char* name, 938 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, 939 bool is_input_section, Output_section_order order, 940 bool is_relro) 941 { 942 // We should not see any input sections after we have attached 943 // sections to segments. 944 gold_assert(!is_input_section || !this->sections_are_attached_); 945 946 flags = this->get_output_section_flags(flags); 947 948 if (this->script_options_->saw_sections_clause()) 949 { 950 // We are using a SECTIONS clause, so the output section is 951 // chosen based only on the name. 952 953 Script_sections* ss = this->script_options_->script_sections(); 954 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); 955 Output_section** output_section_slot; 956 Script_sections::Section_type script_section_type; 957 const char* orig_name = name; 958 bool keep; 959 name = ss->output_section_name(file_name, name, &output_section_slot, 960 &script_section_type, &keep); 961 962 if (name == NULL) 963 { 964 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' " 965 "because it is not allowed by the " 966 "SECTIONS clause of the linker script"), 967 orig_name); 968 // The SECTIONS clause says to discard this input section. 969 return NULL; 970 } 971 972 // We can only handle script section types ST_NONE and ST_NOLOAD. 973 switch (script_section_type) 974 { 975 case Script_sections::ST_NONE: 976 break; 977 case Script_sections::ST_NOLOAD: 978 flags &= elfcpp::SHF_ALLOC; 979 break; 980 default: 981 gold_unreachable(); 982 } 983 984 // If this is an orphan section--one not mentioned in the linker 985 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the 986 // default processing below. 987 988 if (output_section_slot != NULL) 989 { 990 if (*output_section_slot != NULL) 991 { 992 (*output_section_slot)->update_flags_for_input_section(flags); 993 return *output_section_slot; 994 } 995 996 // We don't put sections found in the linker script into 997 // SECTION_NAME_MAP_. That keeps us from getting confused 998 // if an orphan section is mapped to a section with the same 999 // name as one in the linker script. 1000 1001 name = this->namepool_.add(name, false, NULL); 1002 1003 Output_section* os = this->make_output_section(name, type, flags, 1004 order, is_relro); 1005 1006 os->set_found_in_sections_clause(); 1007 1008 // Special handling for NOLOAD sections. 1009 if (script_section_type == Script_sections::ST_NOLOAD) 1010 { 1011 os->set_is_noload(); 1012 1013 // The constructor of Output_section sets addresses of non-ALLOC 1014 // sections to 0 by default. We don't want that for NOLOAD 1015 // sections even if they have no SHF_ALLOC flag. 1016 if ((os->flags() & elfcpp::SHF_ALLOC) == 0 1017 && os->is_address_valid()) 1018 { 1019 gold_assert(os->address() == 0 1020 && !os->is_offset_valid() 1021 && !os->is_data_size_valid()); 1022 os->reset_address_and_file_offset(); 1023 } 1024 } 1025 1026 *output_section_slot = os; 1027 return os; 1028 } 1029 } 1030 1031 // FIXME: Handle SHF_OS_NONCONFORMING somewhere. 1032 1033 size_t len = strlen(name); 1034 std::string uncompressed_name; 1035 1036 // Compressed debug sections should be mapped to the corresponding 1037 // uncompressed section. 1038 if (is_compressed_debug_section(name)) 1039 { 1040 uncompressed_name = 1041 corresponding_uncompressed_section_name(std::string(name, len)); 1042 name = uncompressed_name.c_str(); 1043 len = uncompressed_name.length(); 1044 } 1045 1046 // Turn NAME from the name of the input section into the name of the 1047 // output section. 1048 if (is_input_section 1049 && !this->script_options_->saw_sections_clause() 1050 && !parameters->options().relocatable()) 1051 { 1052 const char *orig_name = name; 1053 name = parameters->target().output_section_name(relobj, name, &len); 1054 if (name == NULL) 1055 name = Layout::output_section_name(relobj, orig_name, &len); 1056 } 1057 1058 Stringpool::Key name_key; 1059 name = this->namepool_.add_with_length(name, len, true, &name_key); 1060 1061 // Find or make the output section. The output section is selected 1062 // based on the section name, type, and flags. 1063 return this->get_output_section(name, name_key, type, flags, order, is_relro); 1064 } 1065 1066 // For incremental links, record the initial fixed layout of a section 1067 // from the base file, and return a pointer to the Output_section. 1068 1069 template<int size, bool big_endian> 1070 Output_section* 1071 Layout::init_fixed_output_section(const char* name, 1072 elfcpp::Shdr<size, big_endian>& shdr) 1073 { 1074 unsigned int sh_type = shdr.get_sh_type(); 1075 1076 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY, 1077 // PRE_INIT_ARRAY, and NOTE sections. 1078 // All others will be created from scratch and reallocated. 1079 if (!can_incremental_update(sh_type)) 1080 return NULL; 1081 1082 // If we're generating a .gdb_index section, we need to regenerate 1083 // it from scratch. 1084 if (parameters->options().gdb_index() 1085 && sh_type == elfcpp::SHT_PROGBITS 1086 && strcmp(name, ".gdb_index") == 0) 1087 return NULL; 1088 1089 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr(); 1090 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset(); 1091 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size(); 1092 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags(); 1093 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign = 1094 shdr.get_sh_addralign(); 1095 1096 // Make the output section. 1097 Stringpool::Key name_key; 1098 name = this->namepool_.add(name, true, &name_key); 1099 Output_section* os = this->get_output_section(name, name_key, sh_type, 1100 sh_flags, ORDER_INVALID, false); 1101 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign); 1102 if (sh_type != elfcpp::SHT_NOBITS) 1103 this->free_list_.remove(sh_offset, sh_offset + sh_size); 1104 return os; 1105 } 1106 1107 // Return the index by which an input section should be ordered. This 1108 // is used to sort some .text sections, for compatibility with GNU ld. 1109 1110 int 1111 Layout::special_ordering_of_input_section(const char* name) 1112 { 1113 // The GNU linker has some special handling for some sections that 1114 // wind up in the .text section. Sections that start with these 1115 // prefixes must appear first, and must appear in the order listed 1116 // here. 1117 static const char* const text_section_sort[] = 1118 { 1119 ".text.unlikely", 1120 ".text.exit", 1121 ".text.startup", 1122 ".text.hot" 1123 }; 1124 1125 for (size_t i = 0; 1126 i < sizeof(text_section_sort) / sizeof(text_section_sort[0]); 1127 i++) 1128 if (is_prefix_of(text_section_sort[i], name)) 1129 return i; 1130 1131 return -1; 1132 } 1133 1134 // Return the output section to use for input section SHNDX, with name 1135 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the 1136 // index of a relocation section which applies to this section, or 0 1137 // if none, or -1U if more than one. RELOC_TYPE is the type of the 1138 // relocation section if there is one. Set *OFF to the offset of this 1139 // input section without the output section. Return NULL if the 1140 // section should be discarded. Set *OFF to -1 if the section 1141 // contents should not be written directly to the output file, but 1142 // will instead receive special handling. 1143 1144 template<int size, bool big_endian> 1145 Output_section* 1146 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx, 1147 const char* name, const elfcpp::Shdr<size, big_endian>& shdr, 1148 unsigned int reloc_shndx, unsigned int, off_t* off) 1149 { 1150 *off = 0; 1151 1152 if (!this->include_section(object, name, shdr)) 1153 return NULL; 1154 1155 elfcpp::Elf_Word sh_type = shdr.get_sh_type(); 1156 1157 // In a relocatable link a grouped section must not be combined with 1158 // any other sections. 1159 Output_section* os; 1160 if (parameters->options().relocatable() 1161 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0) 1162 { 1163 // Some flags in the input section should not be automatically 1164 // copied to the output section. 1165 elfcpp::Elf_Xword flags = (shdr.get_sh_flags() 1166 & ~ elfcpp::SHF_COMPRESSED); 1167 name = this->namepool_.add(name, true, NULL); 1168 os = this->make_output_section(name, sh_type, flags, 1169 ORDER_INVALID, false); 1170 } 1171 else 1172 { 1173 // Plugins can choose to place one or more subsets of sections in 1174 // unique segments and this is done by mapping these section subsets 1175 // to unique output sections. Check if this section needs to be 1176 // remapped to a unique output section. 1177 Section_segment_map::iterator it 1178 = this->section_segment_map_.find(Const_section_id(object, shndx)); 1179 if (it == this->section_segment_map_.end()) 1180 { 1181 os = this->choose_output_section(object, name, sh_type, 1182 shdr.get_sh_flags(), true, 1183 ORDER_INVALID, false); 1184 } 1185 else 1186 { 1187 // We know the name of the output section, directly call 1188 // get_output_section here by-passing choose_output_section. 1189 elfcpp::Elf_Xword flags 1190 = this->get_output_section_flags(shdr.get_sh_flags()); 1191 1192 const char* os_name = it->second->name; 1193 Stringpool::Key name_key; 1194 os_name = this->namepool_.add(os_name, true, &name_key); 1195 os = this->get_output_section(os_name, name_key, sh_type, flags, 1196 ORDER_INVALID, false); 1197 if (!os->is_unique_segment()) 1198 { 1199 os->set_is_unique_segment(); 1200 os->set_extra_segment_flags(it->second->flags); 1201 os->set_segment_alignment(it->second->align); 1202 } 1203 } 1204 if (os == NULL) 1205 return NULL; 1206 } 1207 1208 // By default the GNU linker sorts input sections whose names match 1209 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The 1210 // sections are sorted by name. This is used to implement 1211 // constructor priority ordering. We are compatible. When we put 1212 // .ctor sections in .init_array and .dtor sections in .fini_array, 1213 // we must also sort plain .ctor and .dtor sections. 1214 if (!this->script_options_->saw_sections_clause() 1215 && !parameters->options().relocatable() 1216 && (is_prefix_of(".ctors.", name) 1217 || is_prefix_of(".dtors.", name) 1218 || is_prefix_of(".init_array.", name) 1219 || is_prefix_of(".fini_array.", name) 1220 || (parameters->options().ctors_in_init_array() 1221 && (strcmp(name, ".ctors") == 0 1222 || strcmp(name, ".dtors") == 0)))) 1223 os->set_must_sort_attached_input_sections(); 1224 1225 // By default the GNU linker sorts some special text sections ahead 1226 // of others. We are compatible. 1227 if (parameters->options().text_reorder() 1228 && !this->script_options_->saw_sections_clause() 1229 && !this->is_section_ordering_specified() 1230 && !parameters->options().relocatable() 1231 && Layout::special_ordering_of_input_section(name) >= 0) 1232 os->set_must_sort_attached_input_sections(); 1233 1234 // If this is a .ctors or .ctors.* section being mapped to a 1235 // .init_array section, or a .dtors or .dtors.* section being mapped 1236 // to a .fini_array section, we will need to reverse the words if 1237 // there is more than one. Record this section for later. See 1238 // ctors_sections_in_init_array above. 1239 if (!this->script_options_->saw_sections_clause() 1240 && !parameters->options().relocatable() 1241 && shdr.get_sh_size() > size / 8 1242 && (((strcmp(name, ".ctors") == 0 1243 || is_prefix_of(".ctors.", name)) 1244 && strcmp(os->name(), ".init_array") == 0) 1245 || ((strcmp(name, ".dtors") == 0 1246 || is_prefix_of(".dtors.", name)) 1247 && strcmp(os->name(), ".fini_array") == 0))) 1248 ctors_sections_in_init_array.insert(Section_id(object, shndx)); 1249 1250 // FIXME: Handle SHF_LINK_ORDER somewhere. 1251 1252 elfcpp::Elf_Xword orig_flags = os->flags(); 1253 1254 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, 1255 this->script_options_->saw_sections_clause()); 1256 1257 // If the flags changed, we may have to change the order. 1258 if ((orig_flags & elfcpp::SHF_ALLOC) != 0) 1259 { 1260 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); 1261 elfcpp::Elf_Xword new_flags = 1262 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); 1263 if (orig_flags != new_flags) 1264 os->set_order(this->default_section_order(os, false)); 1265 } 1266 1267 this->have_added_input_section_ = true; 1268 1269 return os; 1270 } 1271 1272 // Maps section SECN to SEGMENT s. 1273 void 1274 Layout::insert_section_segment_map(Const_section_id secn, 1275 Unique_segment_info *s) 1276 { 1277 gold_assert(this->unique_segment_for_sections_specified_); 1278 this->section_segment_map_[secn] = s; 1279 } 1280 1281 // Handle a relocation section when doing a relocatable link. 1282 1283 template<int size, bool big_endian> 1284 Output_section* 1285 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object, 1286 unsigned int, 1287 const elfcpp::Shdr<size, big_endian>& shdr, 1288 Output_section* data_section, 1289 Relocatable_relocs* rr) 1290 { 1291 gold_assert(parameters->options().relocatable() 1292 || parameters->options().emit_relocs()); 1293 1294 int sh_type = shdr.get_sh_type(); 1295 1296 std::string name; 1297 if (sh_type == elfcpp::SHT_REL) 1298 name = ".rel"; 1299 else if (sh_type == elfcpp::SHT_RELA) 1300 name = ".rela"; 1301 else 1302 gold_unreachable(); 1303 name += data_section->name(); 1304 1305 // In a relocatable link relocs for a grouped section must not be 1306 // combined with other reloc sections. 1307 Output_section* os; 1308 if (!parameters->options().relocatable() 1309 || (data_section->flags() & elfcpp::SHF_GROUP) == 0) 1310 os = this->choose_output_section(object, name.c_str(), sh_type, 1311 shdr.get_sh_flags(), false, 1312 ORDER_INVALID, false); 1313 else 1314 { 1315 const char* n = this->namepool_.add(name.c_str(), true, NULL); 1316 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(), 1317 ORDER_INVALID, false); 1318 } 1319 1320 os->set_should_link_to_symtab(); 1321 os->set_info_section(data_section); 1322 1323 Output_section_data* posd; 1324 if (sh_type == elfcpp::SHT_REL) 1325 { 1326 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size); 1327 posd = new Output_relocatable_relocs<elfcpp::SHT_REL, 1328 size, 1329 big_endian>(rr); 1330 } 1331 else if (sh_type == elfcpp::SHT_RELA) 1332 { 1333 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size); 1334 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA, 1335 size, 1336 big_endian>(rr); 1337 } 1338 else 1339 gold_unreachable(); 1340 1341 os->add_output_section_data(posd); 1342 rr->set_output_data(posd); 1343 1344 return os; 1345 } 1346 1347 // Handle a group section when doing a relocatable link. 1348 1349 template<int size, bool big_endian> 1350 void 1351 Layout::layout_group(Symbol_table* symtab, 1352 Sized_relobj_file<size, big_endian>* object, 1353 unsigned int, 1354 const char* group_section_name, 1355 const char* signature, 1356 const elfcpp::Shdr<size, big_endian>& shdr, 1357 elfcpp::Elf_Word flags, 1358 std::vector<unsigned int>* shndxes) 1359 { 1360 gold_assert(parameters->options().relocatable()); 1361 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP); 1362 group_section_name = this->namepool_.add(group_section_name, true, NULL); 1363 Output_section* os = this->make_output_section(group_section_name, 1364 elfcpp::SHT_GROUP, 1365 shdr.get_sh_flags(), 1366 ORDER_INVALID, false); 1367 1368 // We need to find a symbol with the signature in the symbol table. 1369 // If we don't find one now, we need to look again later. 1370 Symbol* sym = symtab->lookup(signature, NULL); 1371 if (sym != NULL) 1372 os->set_info_symndx(sym); 1373 else 1374 { 1375 // Reserve some space to minimize reallocations. 1376 if (this->group_signatures_.empty()) 1377 this->group_signatures_.reserve(this->number_of_input_files_ * 16); 1378 1379 // We will wind up using a symbol whose name is the signature. 1380 // So just put the signature in the symbol name pool to save it. 1381 signature = symtab->canonicalize_name(signature); 1382 this->group_signatures_.push_back(Group_signature(os, signature)); 1383 } 1384 1385 os->set_should_link_to_symtab(); 1386 os->set_entsize(4); 1387 1388 section_size_type entry_count = 1389 convert_to_section_size_type(shdr.get_sh_size() / 4); 1390 Output_section_data* posd = 1391 new Output_data_group<size, big_endian>(object, entry_count, flags, 1392 shndxes); 1393 os->add_output_section_data(posd); 1394 } 1395 1396 // Special GNU handling of sections name .eh_frame. They will 1397 // normally hold exception frame data as defined by the C++ ABI 1398 // (http://codesourcery.com/cxx-abi/). 1399 1400 template<int size, bool big_endian> 1401 Output_section* 1402 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object, 1403 const unsigned char* symbols, 1404 off_t symbols_size, 1405 const unsigned char* symbol_names, 1406 off_t symbol_names_size, 1407 unsigned int shndx, 1408 const elfcpp::Shdr<size, big_endian>& shdr, 1409 unsigned int reloc_shndx, unsigned int reloc_type, 1410 off_t* off) 1411 { 1412 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS 1413 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND); 1414 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0); 1415 1416 Output_section* os = this->make_eh_frame_section(object); 1417 if (os == NULL) 1418 return NULL; 1419 1420 gold_assert(this->eh_frame_section_ == os); 1421 1422 elfcpp::Elf_Xword orig_flags = os->flags(); 1423 1424 Eh_frame::Eh_frame_section_disposition disp = 1425 Eh_frame::EH_UNRECOGNIZED_SECTION; 1426 if (!parameters->incremental()) 1427 { 1428 disp = this->eh_frame_data_->add_ehframe_input_section(object, 1429 symbols, 1430 symbols_size, 1431 symbol_names, 1432 symbol_names_size, 1433 shndx, 1434 reloc_shndx, 1435 reloc_type); 1436 } 1437 1438 if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION) 1439 { 1440 os->update_flags_for_input_section(shdr.get_sh_flags()); 1441 1442 // A writable .eh_frame section is a RELRO section. 1443 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) 1444 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) 1445 { 1446 os->set_is_relro(); 1447 os->set_order(ORDER_RELRO); 1448 } 1449 1450 *off = -1; 1451 return os; 1452 } 1453 1454 if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_) 1455 { 1456 // We found the end marker section, so now we can add the set of 1457 // optimized sections to the output section. We need to postpone 1458 // adding this until we've found a section we can optimize so that 1459 // the .eh_frame section in crtbeginT.o winds up at the start of 1460 // the output section. 1461 os->add_output_section_data(this->eh_frame_data_); 1462 this->added_eh_frame_data_ = true; 1463 } 1464 1465 // We couldn't handle this .eh_frame section for some reason. 1466 // Add it as a normal section. 1467 bool saw_sections_clause = this->script_options_->saw_sections_clause(); 1468 *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr, 1469 reloc_shndx, saw_sections_clause); 1470 this->have_added_input_section_ = true; 1471 1472 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) 1473 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) 1474 os->set_order(this->default_section_order(os, false)); 1475 1476 return os; 1477 } 1478 1479 void 1480 Layout::finalize_eh_frame_section() 1481 { 1482 // If we never found an end marker section, we need to add the 1483 // optimized eh sections to the output section now. 1484 if (!parameters->incremental() 1485 && this->eh_frame_section_ != NULL 1486 && !this->added_eh_frame_data_) 1487 { 1488 this->eh_frame_section_->add_output_section_data(this->eh_frame_data_); 1489 this->added_eh_frame_data_ = true; 1490 } 1491 } 1492 1493 // Create and return the magic .eh_frame section. Create 1494 // .eh_frame_hdr also if appropriate. OBJECT is the object with the 1495 // input .eh_frame section; it may be NULL. 1496 1497 Output_section* 1498 Layout::make_eh_frame_section(const Relobj* object) 1499 { 1500 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than 1501 // SHT_PROGBITS. 1502 Output_section* os = this->choose_output_section(object, ".eh_frame", 1503 elfcpp::SHT_PROGBITS, 1504 elfcpp::SHF_ALLOC, false, 1505 ORDER_EHFRAME, false); 1506 if (os == NULL) 1507 return NULL; 1508 1509 if (this->eh_frame_section_ == NULL) 1510 { 1511 this->eh_frame_section_ = os; 1512 this->eh_frame_data_ = new Eh_frame(); 1513 1514 // For incremental linking, we do not optimize .eh_frame sections 1515 // or create a .eh_frame_hdr section. 1516 if (parameters->options().eh_frame_hdr() && !parameters->incremental()) 1517 { 1518 Output_section* hdr_os = 1519 this->choose_output_section(NULL, ".eh_frame_hdr", 1520 elfcpp::SHT_PROGBITS, 1521 elfcpp::SHF_ALLOC, false, 1522 ORDER_EHFRAME, false); 1523 1524 if (hdr_os != NULL) 1525 { 1526 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os, 1527 this->eh_frame_data_); 1528 hdr_os->add_output_section_data(hdr_posd); 1529 1530 hdr_os->set_after_input_sections(); 1531 1532 if (!this->script_options_->saw_phdrs_clause()) 1533 { 1534 Output_segment* hdr_oseg; 1535 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME, 1536 elfcpp::PF_R); 1537 hdr_oseg->add_output_section_to_nonload(hdr_os, 1538 elfcpp::PF_R); 1539 } 1540 1541 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd); 1542 } 1543 } 1544 } 1545 1546 return os; 1547 } 1548 1549 // Add an exception frame for a PLT. This is called from target code. 1550 1551 void 1552 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, 1553 size_t cie_length, const unsigned char* fde_data, 1554 size_t fde_length) 1555 { 1556 if (parameters->incremental()) 1557 { 1558 // FIXME: Maybe this could work some day.... 1559 return; 1560 } 1561 Output_section* os = this->make_eh_frame_section(NULL); 1562 if (os == NULL) 1563 return; 1564 this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length, 1565 fde_data, fde_length); 1566 if (!this->added_eh_frame_data_) 1567 { 1568 os->add_output_section_data(this->eh_frame_data_); 1569 this->added_eh_frame_data_ = true; 1570 } 1571 } 1572 1573 // Scan a .debug_info or .debug_types section, and add summary 1574 // information to the .gdb_index section. 1575 1576 template<int size, bool big_endian> 1577 void 1578 Layout::add_to_gdb_index(bool is_type_unit, 1579 Sized_relobj<size, big_endian>* object, 1580 const unsigned char* symbols, 1581 off_t symbols_size, 1582 unsigned int shndx, 1583 unsigned int reloc_shndx, 1584 unsigned int reloc_type) 1585 { 1586 if (this->gdb_index_data_ == NULL) 1587 { 1588 Output_section* os = this->choose_output_section(NULL, ".gdb_index", 1589 elfcpp::SHT_PROGBITS, 0, 1590 false, ORDER_INVALID, 1591 false); 1592 if (os == NULL) 1593 return; 1594 1595 this->gdb_index_data_ = new Gdb_index(os); 1596 os->add_output_section_data(this->gdb_index_data_); 1597 os->set_after_input_sections(); 1598 } 1599 1600 this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols, 1601 symbols_size, shndx, reloc_shndx, 1602 reloc_type); 1603 } 1604 1605 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return 1606 // the output section. 1607 1608 Output_section* 1609 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type, 1610 elfcpp::Elf_Xword flags, 1611 Output_section_data* posd, 1612 Output_section_order order, bool is_relro) 1613 { 1614 Output_section* os = this->choose_output_section(NULL, name, type, flags, 1615 false, order, is_relro); 1616 if (os != NULL) 1617 os->add_output_section_data(posd); 1618 return os; 1619 } 1620 1621 // Map section flags to segment flags. 1622 1623 elfcpp::Elf_Word 1624 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags) 1625 { 1626 elfcpp::Elf_Word ret = elfcpp::PF_R; 1627 if ((flags & elfcpp::SHF_WRITE) != 0) 1628 ret |= elfcpp::PF_W; 1629 if ((flags & elfcpp::SHF_EXECINSTR) != 0) 1630 ret |= elfcpp::PF_X; 1631 return ret; 1632 } 1633 1634 // Make a new Output_section, and attach it to segments as 1635 // appropriate. ORDER is the order in which this section should 1636 // appear in the output segment. IS_RELRO is true if this is a relro 1637 // (read-only after relocations) section. 1638 1639 Output_section* 1640 Layout::make_output_section(const char* name, elfcpp::Elf_Word type, 1641 elfcpp::Elf_Xword flags, 1642 Output_section_order order, bool is_relro) 1643 { 1644 Output_section* os; 1645 if ((flags & elfcpp::SHF_ALLOC) == 0 1646 && strcmp(parameters->options().compress_debug_sections(), "none") != 0 1647 && is_compressible_debug_section(name)) 1648 os = new Output_compressed_section(¶meters->options(), name, type, 1649 flags); 1650 else if ((flags & elfcpp::SHF_ALLOC) == 0 1651 && parameters->options().strip_debug_non_line() 1652 && strcmp(".debug_abbrev", name) == 0) 1653 { 1654 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section( 1655 name, type, flags); 1656 if (this->debug_info_) 1657 this->debug_info_->set_abbreviations(this->debug_abbrev_); 1658 } 1659 else if ((flags & elfcpp::SHF_ALLOC) == 0 1660 && parameters->options().strip_debug_non_line() 1661 && strcmp(".debug_info", name) == 0) 1662 { 1663 os = this->debug_info_ = new Output_reduced_debug_info_section( 1664 name, type, flags); 1665 if (this->debug_abbrev_) 1666 this->debug_info_->set_abbreviations(this->debug_abbrev_); 1667 } 1668 else 1669 { 1670 // Sometimes .init_array*, .preinit_array* and .fini_array* do 1671 // not have correct section types. Force them here. 1672 if (type == elfcpp::SHT_PROGBITS) 1673 { 1674 if (is_prefix_of(".init_array", name)) 1675 type = elfcpp::SHT_INIT_ARRAY; 1676 else if (is_prefix_of(".preinit_array", name)) 1677 type = elfcpp::SHT_PREINIT_ARRAY; 1678 else if (is_prefix_of(".fini_array", name)) 1679 type = elfcpp::SHT_FINI_ARRAY; 1680 } 1681 1682 // FIXME: const_cast is ugly. 1683 Target* target = const_cast<Target*>(¶meters->target()); 1684 os = target->make_output_section(name, type, flags); 1685 } 1686 1687 // With -z relro, we have to recognize the special sections by name. 1688 // There is no other way. 1689 bool is_relro_local = false; 1690 if (!this->script_options_->saw_sections_clause() 1691 && parameters->options().relro() 1692 && (flags & elfcpp::SHF_ALLOC) != 0 1693 && (flags & elfcpp::SHF_WRITE) != 0) 1694 { 1695 if (type == elfcpp::SHT_PROGBITS) 1696 { 1697 if ((flags & elfcpp::SHF_TLS) != 0) 1698 is_relro = true; 1699 else if (strcmp(name, ".data.rel.ro") == 0) 1700 is_relro = true; 1701 else if (strcmp(name, ".data.rel.ro.local") == 0) 1702 { 1703 is_relro = true; 1704 is_relro_local = true; 1705 } 1706 else if (strcmp(name, ".ctors") == 0 1707 || strcmp(name, ".dtors") == 0 1708 || strcmp(name, ".jcr") == 0) 1709 is_relro = true; 1710 } 1711 else if (type == elfcpp::SHT_INIT_ARRAY 1712 || type == elfcpp::SHT_FINI_ARRAY 1713 || type == elfcpp::SHT_PREINIT_ARRAY) 1714 is_relro = true; 1715 } 1716 1717 if (is_relro) 1718 os->set_is_relro(); 1719 1720 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0) 1721 order = this->default_section_order(os, is_relro_local); 1722 1723 os->set_order(order); 1724 1725 parameters->target().new_output_section(os); 1726 1727 this->section_list_.push_back(os); 1728 1729 // The GNU linker by default sorts some sections by priority, so we 1730 // do the same. We need to know that this might happen before we 1731 // attach any input sections. 1732 if (!this->script_options_->saw_sections_clause() 1733 && !parameters->options().relocatable() 1734 && (strcmp(name, ".init_array") == 0 1735 || strcmp(name, ".fini_array") == 0 1736 || (!parameters->options().ctors_in_init_array() 1737 && (strcmp(name, ".ctors") == 0 1738 || strcmp(name, ".dtors") == 0)))) 1739 os->set_may_sort_attached_input_sections(); 1740 1741 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot} 1742 // sections before other .text sections. We are compatible. We 1743 // need to know that this might happen before we attach any input 1744 // sections. 1745 if (parameters->options().text_reorder() 1746 && !this->script_options_->saw_sections_clause() 1747 && !this->is_section_ordering_specified() 1748 && !parameters->options().relocatable() 1749 && strcmp(name, ".text") == 0) 1750 os->set_may_sort_attached_input_sections(); 1751 1752 // GNU linker sorts section by name with --sort-section=name. 1753 if (strcmp(parameters->options().sort_section(), "name") == 0) 1754 os->set_must_sort_attached_input_sections(); 1755 1756 // Check for .stab*str sections, as .stab* sections need to link to 1757 // them. 1758 if (type == elfcpp::SHT_STRTAB 1759 && !this->have_stabstr_section_ 1760 && strncmp(name, ".stab", 5) == 0 1761 && strcmp(name + strlen(name) - 3, "str") == 0) 1762 this->have_stabstr_section_ = true; 1763 1764 // During a full incremental link, we add patch space to most 1765 // PROGBITS and NOBITS sections. Flag those that may be 1766 // arbitrarily padded. 1767 if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS) 1768 && order != ORDER_INTERP 1769 && order != ORDER_INIT 1770 && order != ORDER_PLT 1771 && order != ORDER_FINI 1772 && order != ORDER_RELRO_LAST 1773 && order != ORDER_NON_RELRO_FIRST 1774 && strcmp(name, ".eh_frame") != 0 1775 && strcmp(name, ".ctors") != 0 1776 && strcmp(name, ".dtors") != 0 1777 && strcmp(name, ".jcr") != 0) 1778 { 1779 os->set_is_patch_space_allowed(); 1780 1781 // Certain sections require "holes" to be filled with 1782 // specific fill patterns. These fill patterns may have 1783 // a minimum size, so we must prevent allocations from the 1784 // free list that leave a hole smaller than the minimum. 1785 if (strcmp(name, ".debug_info") == 0) 1786 os->set_free_space_fill(new Output_fill_debug_info(false)); 1787 else if (strcmp(name, ".debug_types") == 0) 1788 os->set_free_space_fill(new Output_fill_debug_info(true)); 1789 else if (strcmp(name, ".debug_line") == 0) 1790 os->set_free_space_fill(new Output_fill_debug_line()); 1791 } 1792 1793 // If we have already attached the sections to segments, then we 1794 // need to attach this one now. This happens for sections created 1795 // directly by the linker. 1796 if (this->sections_are_attached_) 1797 this->attach_section_to_segment(¶meters->target(), os); 1798 1799 return os; 1800 } 1801 1802 // Return the default order in which a section should be placed in an 1803 // output segment. This function captures a lot of the ideas in 1804 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a 1805 // linker created section is normally set when the section is created; 1806 // this function is used for input sections. 1807 1808 Output_section_order 1809 Layout::default_section_order(Output_section* os, bool is_relro_local) 1810 { 1811 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); 1812 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0; 1813 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0; 1814 bool is_bss = false; 1815 1816 switch (os->type()) 1817 { 1818 default: 1819 case elfcpp::SHT_PROGBITS: 1820 break; 1821 case elfcpp::SHT_NOBITS: 1822 is_bss = true; 1823 break; 1824 case elfcpp::SHT_RELA: 1825 case elfcpp::SHT_REL: 1826 if (!is_write) 1827 return ORDER_DYNAMIC_RELOCS; 1828 break; 1829 case elfcpp::SHT_HASH: 1830 case elfcpp::SHT_DYNAMIC: 1831 case elfcpp::SHT_SHLIB: 1832 case elfcpp::SHT_DYNSYM: 1833 case elfcpp::SHT_GNU_HASH: 1834 case elfcpp::SHT_GNU_verdef: 1835 case elfcpp::SHT_GNU_verneed: 1836 case elfcpp::SHT_GNU_versym: 1837 if (!is_write) 1838 return ORDER_DYNAMIC_LINKER; 1839 break; 1840 case elfcpp::SHT_NOTE: 1841 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE; 1842 } 1843 1844 if ((os->flags() & elfcpp::SHF_TLS) != 0) 1845 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA; 1846 1847 if (!is_bss && !is_write) 1848 { 1849 if (is_execinstr) 1850 { 1851 if (strcmp(os->name(), ".init") == 0) 1852 return ORDER_INIT; 1853 else if (strcmp(os->name(), ".fini") == 0) 1854 return ORDER_FINI; 1855 } 1856 return is_execinstr ? ORDER_TEXT : ORDER_READONLY; 1857 } 1858 1859 if (os->is_relro()) 1860 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO; 1861 1862 if (os->is_small_section()) 1863 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA; 1864 if (os->is_large_section()) 1865 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA; 1866 1867 return is_bss ? ORDER_BSS : ORDER_DATA; 1868 } 1869 1870 // Attach output sections to segments. This is called after we have 1871 // seen all the input sections. 1872 1873 void 1874 Layout::attach_sections_to_segments(const Target* target) 1875 { 1876 for (Section_list::iterator p = this->section_list_.begin(); 1877 p != this->section_list_.end(); 1878 ++p) 1879 this->attach_section_to_segment(target, *p); 1880 1881 this->sections_are_attached_ = true; 1882 } 1883 1884 // Attach an output section to a segment. 1885 1886 void 1887 Layout::attach_section_to_segment(const Target* target, Output_section* os) 1888 { 1889 if ((os->flags() & elfcpp::SHF_ALLOC) == 0) 1890 this->unattached_section_list_.push_back(os); 1891 else 1892 this->attach_allocated_section_to_segment(target, os); 1893 } 1894 1895 // Attach an allocated output section to a segment. 1896 1897 void 1898 Layout::attach_allocated_section_to_segment(const Target* target, 1899 Output_section* os) 1900 { 1901 elfcpp::Elf_Xword flags = os->flags(); 1902 gold_assert((flags & elfcpp::SHF_ALLOC) != 0); 1903 1904 if (parameters->options().relocatable()) 1905 return; 1906 1907 // If we have a SECTIONS clause, we can't handle the attachment to 1908 // segments until after we've seen all the sections. 1909 if (this->script_options_->saw_sections_clause()) 1910 return; 1911 1912 gold_assert(!this->script_options_->saw_phdrs_clause()); 1913 1914 // This output section goes into a PT_LOAD segment. 1915 1916 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags); 1917 1918 // If this output section's segment has extra flags that need to be set, 1919 // coming from a linker plugin, do that. 1920 seg_flags |= os->extra_segment_flags(); 1921 1922 // Check for --section-start. 1923 uint64_t addr; 1924 bool is_address_set = parameters->options().section_start(os->name(), &addr); 1925 1926 // In general the only thing we really care about for PT_LOAD 1927 // segments is whether or not they are writable or executable, 1928 // so that is how we search for them. 1929 // Large data sections also go into their own PT_LOAD segment. 1930 // People who need segments sorted on some other basis will 1931 // have to use a linker script. 1932 1933 Segment_list::const_iterator p; 1934 if (!os->is_unique_segment()) 1935 { 1936 for (p = this->segment_list_.begin(); 1937 p != this->segment_list_.end(); 1938 ++p) 1939 { 1940 if ((*p)->type() != elfcpp::PT_LOAD) 1941 continue; 1942 if ((*p)->is_unique_segment()) 1943 continue; 1944 if (!parameters->options().omagic() 1945 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W)) 1946 continue; 1947 if ((target->isolate_execinstr() || parameters->options().rosegment()) 1948 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X)) 1949 continue; 1950 // If -Tbss was specified, we need to separate the data and BSS 1951 // segments. 1952 if (parameters->options().user_set_Tbss()) 1953 { 1954 if ((os->type() == elfcpp::SHT_NOBITS) 1955 == (*p)->has_any_data_sections()) 1956 continue; 1957 } 1958 if (os->is_large_data_section() && !(*p)->is_large_data_segment()) 1959 continue; 1960 1961 if (is_address_set) 1962 { 1963 if ((*p)->are_addresses_set()) 1964 continue; 1965 1966 (*p)->add_initial_output_data(os); 1967 (*p)->update_flags_for_output_section(seg_flags); 1968 (*p)->set_addresses(addr, addr); 1969 break; 1970 } 1971 1972 (*p)->add_output_section_to_load(this, os, seg_flags); 1973 break; 1974 } 1975 } 1976 1977 if (p == this->segment_list_.end() 1978 || os->is_unique_segment()) 1979 { 1980 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD, 1981 seg_flags); 1982 if (os->is_large_data_section()) 1983 oseg->set_is_large_data_segment(); 1984 oseg->add_output_section_to_load(this, os, seg_flags); 1985 if (is_address_set) 1986 oseg->set_addresses(addr, addr); 1987 // Check if segment should be marked unique. For segments marked 1988 // unique by linker plugins, set the new alignment if specified. 1989 if (os->is_unique_segment()) 1990 { 1991 oseg->set_is_unique_segment(); 1992 if (os->segment_alignment() != 0) 1993 oseg->set_minimum_p_align(os->segment_alignment()); 1994 } 1995 } 1996 1997 // If we see a loadable SHT_NOTE section, we create a PT_NOTE 1998 // segment. 1999 if (os->type() == elfcpp::SHT_NOTE) 2000 { 2001 // See if we already have an equivalent PT_NOTE segment. 2002 for (p = this->segment_list_.begin(); 2003 p != segment_list_.end(); 2004 ++p) 2005 { 2006 if ((*p)->type() == elfcpp::PT_NOTE 2007 && (((*p)->flags() & elfcpp::PF_W) 2008 == (seg_flags & elfcpp::PF_W))) 2009 { 2010 (*p)->add_output_section_to_nonload(os, seg_flags); 2011 break; 2012 } 2013 } 2014 2015 if (p == this->segment_list_.end()) 2016 { 2017 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE, 2018 seg_flags); 2019 oseg->add_output_section_to_nonload(os, seg_flags); 2020 } 2021 } 2022 2023 // If we see a loadable SHF_TLS section, we create a PT_TLS 2024 // segment. There can only be one such segment. 2025 if ((flags & elfcpp::SHF_TLS) != 0) 2026 { 2027 if (this->tls_segment_ == NULL) 2028 this->make_output_segment(elfcpp::PT_TLS, seg_flags); 2029 this->tls_segment_->add_output_section_to_nonload(os, seg_flags); 2030 } 2031 2032 // If -z relro is in effect, and we see a relro section, we create a 2033 // PT_GNU_RELRO segment. There can only be one such segment. 2034 if (os->is_relro() && parameters->options().relro()) 2035 { 2036 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W)); 2037 if (this->relro_segment_ == NULL) 2038 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags); 2039 this->relro_segment_->add_output_section_to_nonload(os, seg_flags); 2040 } 2041 2042 // If we see a section named .interp, put it into a PT_INTERP 2043 // segment. This seems broken to me, but this is what GNU ld does, 2044 // and glibc expects it. 2045 if (strcmp(os->name(), ".interp") == 0 2046 && !this->script_options_->saw_phdrs_clause()) 2047 { 2048 if (this->interp_segment_ == NULL) 2049 this->make_output_segment(elfcpp::PT_INTERP, seg_flags); 2050 else 2051 gold_warning(_("multiple '.interp' sections in input files " 2052 "may cause confusing PT_INTERP segment")); 2053 this->interp_segment_->add_output_section_to_nonload(os, seg_flags); 2054 } 2055 } 2056 2057 // Make an output section for a script. 2058 2059 Output_section* 2060 Layout::make_output_section_for_script( 2061 const char* name, 2062 Script_sections::Section_type section_type) 2063 { 2064 name = this->namepool_.add(name, false, NULL); 2065 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC; 2066 if (section_type == Script_sections::ST_NOLOAD) 2067 sh_flags = 0; 2068 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS, 2069 sh_flags, ORDER_INVALID, 2070 false); 2071 os->set_found_in_sections_clause(); 2072 if (section_type == Script_sections::ST_NOLOAD) 2073 os->set_is_noload(); 2074 return os; 2075 } 2076 2077 // Return the number of segments we expect to see. 2078 2079 size_t 2080 Layout::expected_segment_count() const 2081 { 2082 size_t ret = this->segment_list_.size(); 2083 2084 // If we didn't see a SECTIONS clause in a linker script, we should 2085 // already have the complete list of segments. Otherwise we ask the 2086 // SECTIONS clause how many segments it expects, and add in the ones 2087 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.) 2088 2089 if (!this->script_options_->saw_sections_clause()) 2090 return ret; 2091 else 2092 { 2093 const Script_sections* ss = this->script_options_->script_sections(); 2094 return ret + ss->expected_segment_count(this); 2095 } 2096 } 2097 2098 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK 2099 // is whether we saw a .note.GNU-stack section in the object file. 2100 // GNU_STACK_FLAGS is the section flags. The flags give the 2101 // protection required for stack memory. We record this in an 2102 // executable as a PT_GNU_STACK segment. If an object file does not 2103 // have a .note.GNU-stack segment, we must assume that it is an old 2104 // object. On some targets that will force an executable stack. 2105 2106 void 2107 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags, 2108 const Object* obj) 2109 { 2110 if (!seen_gnu_stack) 2111 { 2112 this->input_without_gnu_stack_note_ = true; 2113 if (parameters->options().warn_execstack() 2114 && parameters->target().is_default_stack_executable()) 2115 gold_warning(_("%s: missing .note.GNU-stack section" 2116 " implies executable stack"), 2117 obj->name().c_str()); 2118 } 2119 else 2120 { 2121 this->input_with_gnu_stack_note_ = true; 2122 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0) 2123 { 2124 this->input_requires_executable_stack_ = true; 2125 if (parameters->options().warn_execstack()) 2126 gold_warning(_("%s: requires executable stack"), 2127 obj->name().c_str()); 2128 } 2129 } 2130 } 2131 2132 // Create automatic note sections. 2133 2134 void 2135 Layout::create_notes() 2136 { 2137 this->create_gold_note(); 2138 this->create_executable_stack_info(); 2139 this->create_build_id(); 2140 } 2141 2142 // Create the dynamic sections which are needed before we read the 2143 // relocs. 2144 2145 void 2146 Layout::create_initial_dynamic_sections(Symbol_table* symtab) 2147 { 2148 if (parameters->doing_static_link()) 2149 return; 2150 2151 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic", 2152 elfcpp::SHT_DYNAMIC, 2153 (elfcpp::SHF_ALLOC 2154 | elfcpp::SHF_WRITE), 2155 false, ORDER_RELRO, 2156 true); 2157 2158 // A linker script may discard .dynamic, so check for NULL. 2159 if (this->dynamic_section_ != NULL) 2160 { 2161 this->dynamic_symbol_ = 2162 symtab->define_in_output_data("_DYNAMIC", NULL, 2163 Symbol_table::PREDEFINED, 2164 this->dynamic_section_, 0, 0, 2165 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL, 2166 elfcpp::STV_HIDDEN, 0, false, false); 2167 2168 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_); 2169 2170 this->dynamic_section_->add_output_section_data(this->dynamic_data_); 2171 } 2172 } 2173 2174 // For each output section whose name can be represented as C symbol, 2175 // define __start and __stop symbols for the section. This is a GNU 2176 // extension. 2177 2178 void 2179 Layout::define_section_symbols(Symbol_table* symtab) 2180 { 2181 for (Section_list::const_iterator p = this->section_list_.begin(); 2182 p != this->section_list_.end(); 2183 ++p) 2184 { 2185 const char* const name = (*p)->name(); 2186 if (is_cident(name)) 2187 { 2188 const std::string name_string(name); 2189 const std::string start_name(cident_section_start_prefix 2190 + name_string); 2191 const std::string stop_name(cident_section_stop_prefix 2192 + name_string); 2193 2194 symtab->define_in_output_data(start_name.c_str(), 2195 NULL, // version 2196 Symbol_table::PREDEFINED, 2197 *p, 2198 0, // value 2199 0, // symsize 2200 elfcpp::STT_NOTYPE, 2201 elfcpp::STB_GLOBAL, 2202 elfcpp::STV_DEFAULT, 2203 0, // nonvis 2204 false, // offset_is_from_end 2205 true); // only_if_ref 2206 2207 symtab->define_in_output_data(stop_name.c_str(), 2208 NULL, // version 2209 Symbol_table::PREDEFINED, 2210 *p, 2211 0, // value 2212 0, // symsize 2213 elfcpp::STT_NOTYPE, 2214 elfcpp::STB_GLOBAL, 2215 elfcpp::STV_DEFAULT, 2216 0, // nonvis 2217 true, // offset_is_from_end 2218 true); // only_if_ref 2219 } 2220 } 2221 } 2222 2223 // Define symbols for group signatures. 2224 2225 void 2226 Layout::define_group_signatures(Symbol_table* symtab) 2227 { 2228 for (Group_signatures::iterator p = this->group_signatures_.begin(); 2229 p != this->group_signatures_.end(); 2230 ++p) 2231 { 2232 Symbol* sym = symtab->lookup(p->signature, NULL); 2233 if (sym != NULL) 2234 p->section->set_info_symndx(sym); 2235 else 2236 { 2237 // Force the name of the group section to the group 2238 // signature, and use the group's section symbol as the 2239 // signature symbol. 2240 if (strcmp(p->section->name(), p->signature) != 0) 2241 { 2242 const char* name = this->namepool_.add(p->signature, 2243 true, NULL); 2244 p->section->set_name(name); 2245 } 2246 p->section->set_needs_symtab_index(); 2247 p->section->set_info_section_symndx(p->section); 2248 } 2249 } 2250 2251 this->group_signatures_.clear(); 2252 } 2253 2254 // Find the first read-only PT_LOAD segment, creating one if 2255 // necessary. 2256 2257 Output_segment* 2258 Layout::find_first_load_seg(const Target* target) 2259 { 2260 Output_segment* best = NULL; 2261 for (Segment_list::const_iterator p = this->segment_list_.begin(); 2262 p != this->segment_list_.end(); 2263 ++p) 2264 { 2265 if ((*p)->type() == elfcpp::PT_LOAD 2266 && ((*p)->flags() & elfcpp::PF_R) != 0 2267 && (parameters->options().omagic() 2268 || ((*p)->flags() & elfcpp::PF_W) == 0) 2269 && (!target->isolate_execinstr() 2270 || ((*p)->flags() & elfcpp::PF_X) == 0)) 2271 { 2272 if (best == NULL || this->segment_precedes(*p, best)) 2273 best = *p; 2274 } 2275 } 2276 if (best != NULL) 2277 return best; 2278 2279 gold_assert(!this->script_options_->saw_phdrs_clause()); 2280 2281 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD, 2282 elfcpp::PF_R); 2283 return load_seg; 2284 } 2285 2286 // Save states of all current output segments. Store saved states 2287 // in SEGMENT_STATES. 2288 2289 void 2290 Layout::save_segments(Segment_states* segment_states) 2291 { 2292 for (Segment_list::const_iterator p = this->segment_list_.begin(); 2293 p != this->segment_list_.end(); 2294 ++p) 2295 { 2296 Output_segment* segment = *p; 2297 // Shallow copy. 2298 Output_segment* copy = new Output_segment(*segment); 2299 (*segment_states)[segment] = copy; 2300 } 2301 } 2302 2303 // Restore states of output segments and delete any segment not found in 2304 // SEGMENT_STATES. 2305 2306 void 2307 Layout::restore_segments(const Segment_states* segment_states) 2308 { 2309 // Go through the segment list and remove any segment added in the 2310 // relaxation loop. 2311 this->tls_segment_ = NULL; 2312 this->relro_segment_ = NULL; 2313 Segment_list::iterator list_iter = this->segment_list_.begin(); 2314 while (list_iter != this->segment_list_.end()) 2315 { 2316 Output_segment* segment = *list_iter; 2317 Segment_states::const_iterator states_iter = 2318 segment_states->find(segment); 2319 if (states_iter != segment_states->end()) 2320 { 2321 const Output_segment* copy = states_iter->second; 2322 // Shallow copy to restore states. 2323 *segment = *copy; 2324 2325 // Also fix up TLS and RELRO segment pointers as appropriate. 2326 if (segment->type() == elfcpp::PT_TLS) 2327 this->tls_segment_ = segment; 2328 else if (segment->type() == elfcpp::PT_GNU_RELRO) 2329 this->relro_segment_ = segment; 2330 2331 ++list_iter; 2332 } 2333 else 2334 { 2335 list_iter = this->segment_list_.erase(list_iter); 2336 // This is a segment created during section layout. It should be 2337 // safe to remove it since we should have removed all pointers to it. 2338 delete segment; 2339 } 2340 } 2341 } 2342 2343 // Clean up after relaxation so that sections can be laid out again. 2344 2345 void 2346 Layout::clean_up_after_relaxation() 2347 { 2348 // Restore the segments to point state just prior to the relaxation loop. 2349 Script_sections* script_section = this->script_options_->script_sections(); 2350 script_section->release_segments(); 2351 this->restore_segments(this->segment_states_); 2352 2353 // Reset section addresses and file offsets 2354 for (Section_list::iterator p = this->section_list_.begin(); 2355 p != this->section_list_.end(); 2356 ++p) 2357 { 2358 (*p)->restore_states(); 2359 2360 // If an input section changes size because of relaxation, 2361 // we need to adjust the section offsets of all input sections. 2362 // after such a section. 2363 if ((*p)->section_offsets_need_adjustment()) 2364 (*p)->adjust_section_offsets(); 2365 2366 (*p)->reset_address_and_file_offset(); 2367 } 2368 2369 // Reset special output object address and file offsets. 2370 for (Data_list::iterator p = this->special_output_list_.begin(); 2371 p != this->special_output_list_.end(); 2372 ++p) 2373 (*p)->reset_address_and_file_offset(); 2374 2375 // A linker script may have created some output section data objects. 2376 // They are useless now. 2377 for (Output_section_data_list::const_iterator p = 2378 this->script_output_section_data_list_.begin(); 2379 p != this->script_output_section_data_list_.end(); 2380 ++p) 2381 delete *p; 2382 this->script_output_section_data_list_.clear(); 2383 2384 // Special-case fill output objects are recreated each time through 2385 // the relaxation loop. 2386 this->reset_relax_output(); 2387 } 2388 2389 void 2390 Layout::reset_relax_output() 2391 { 2392 for (Data_list::const_iterator p = this->relax_output_list_.begin(); 2393 p != this->relax_output_list_.end(); 2394 ++p) 2395 delete *p; 2396 this->relax_output_list_.clear(); 2397 } 2398 2399 // Prepare for relaxation. 2400 2401 void 2402 Layout::prepare_for_relaxation() 2403 { 2404 // Create an relaxation debug check if in debugging mode. 2405 if (is_debugging_enabled(DEBUG_RELAXATION)) 2406 this->relaxation_debug_check_ = new Relaxation_debug_check(); 2407 2408 // Save segment states. 2409 this->segment_states_ = new Segment_states(); 2410 this->save_segments(this->segment_states_); 2411 2412 for(Section_list::const_iterator p = this->section_list_.begin(); 2413 p != this->section_list_.end(); 2414 ++p) 2415 (*p)->save_states(); 2416 2417 if (is_debugging_enabled(DEBUG_RELAXATION)) 2418 this->relaxation_debug_check_->check_output_data_for_reset_values( 2419 this->section_list_, this->special_output_list_, 2420 this->relax_output_list_); 2421 2422 // Also enable recording of output section data from scripts. 2423 this->record_output_section_data_from_script_ = true; 2424 } 2425 2426 // If the user set the address of the text segment, that may not be 2427 // compatible with putting the segment headers and file headers into 2428 // that segment. For isolate_execinstr() targets, it's the rodata 2429 // segment rather than text where we might put the headers. 2430 static inline bool 2431 load_seg_unusable_for_headers(const Target* target) 2432 { 2433 const General_options& options = parameters->options(); 2434 if (target->isolate_execinstr()) 2435 return (options.user_set_Trodata_segment() 2436 && options.Trodata_segment() % target->abi_pagesize() != 0); 2437 else 2438 return (options.user_set_Ttext() 2439 && options.Ttext() % target->abi_pagesize() != 0); 2440 } 2441 2442 // Relaxation loop body: If target has no relaxation, this runs only once 2443 // Otherwise, the target relaxation hook is called at the end of 2444 // each iteration. If the hook returns true, it means re-layout of 2445 // section is required. 2446 // 2447 // The number of segments created by a linking script without a PHDRS 2448 // clause may be affected by section sizes and alignments. There is 2449 // a remote chance that relaxation causes different number of PT_LOAD 2450 // segments are created and sections are attached to different segments. 2451 // Therefore, we always throw away all segments created during section 2452 // layout. In order to be able to restart the section layout, we keep 2453 // a copy of the segment list right before the relaxation loop and use 2454 // that to restore the segments. 2455 // 2456 // PASS is the current relaxation pass number. 2457 // SYMTAB is a symbol table. 2458 // PLOAD_SEG is the address of a pointer for the load segment. 2459 // PHDR_SEG is a pointer to the PHDR segment. 2460 // SEGMENT_HEADERS points to the output segment header. 2461 // FILE_HEADER points to the output file header. 2462 // PSHNDX is the address to store the output section index. 2463 2464 off_t inline 2465 Layout::relaxation_loop_body( 2466 int pass, 2467 Target* target, 2468 Symbol_table* symtab, 2469 Output_segment** pload_seg, 2470 Output_segment* phdr_seg, 2471 Output_segment_headers* segment_headers, 2472 Output_file_header* file_header, 2473 unsigned int* pshndx) 2474 { 2475 // If this is not the first iteration, we need to clean up after 2476 // relaxation so that we can lay out the sections again. 2477 if (pass != 0) 2478 this->clean_up_after_relaxation(); 2479 2480 // If there is a SECTIONS clause, put all the input sections into 2481 // the required order. 2482 Output_segment* load_seg; 2483 if (this->script_options_->saw_sections_clause()) 2484 load_seg = this->set_section_addresses_from_script(symtab); 2485 else if (parameters->options().relocatable()) 2486 load_seg = NULL; 2487 else 2488 load_seg = this->find_first_load_seg(target); 2489 2490 if (parameters->options().oformat_enum() 2491 != General_options::OBJECT_FORMAT_ELF) 2492 load_seg = NULL; 2493 2494 if (load_seg_unusable_for_headers(target)) 2495 { 2496 load_seg = NULL; 2497 phdr_seg = NULL; 2498 } 2499 2500 gold_assert(phdr_seg == NULL 2501 || load_seg != NULL 2502 || this->script_options_->saw_sections_clause()); 2503 2504 // If the address of the load segment we found has been set by 2505 // --section-start rather than by a script, then adjust the VMA and 2506 // LMA downward if possible to include the file and section headers. 2507 uint64_t header_gap = 0; 2508 if (load_seg != NULL 2509 && load_seg->are_addresses_set() 2510 && !this->script_options_->saw_sections_clause() 2511 && !parameters->options().relocatable()) 2512 { 2513 file_header->finalize_data_size(); 2514 segment_headers->finalize_data_size(); 2515 size_t sizeof_headers = (file_header->data_size() 2516 + segment_headers->data_size()); 2517 const uint64_t abi_pagesize = target->abi_pagesize(); 2518 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers; 2519 hdr_paddr &= ~(abi_pagesize - 1); 2520 uint64_t subtract = load_seg->paddr() - hdr_paddr; 2521 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract) 2522 load_seg = NULL; 2523 else 2524 { 2525 load_seg->set_addresses(load_seg->vaddr() - subtract, 2526 load_seg->paddr() - subtract); 2527 header_gap = subtract - sizeof_headers; 2528 } 2529 } 2530 2531 // Lay out the segment headers. 2532 if (!parameters->options().relocatable()) 2533 { 2534 gold_assert(segment_headers != NULL); 2535 if (header_gap != 0 && load_seg != NULL) 2536 { 2537 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1); 2538 load_seg->add_initial_output_data(z); 2539 } 2540 if (load_seg != NULL) 2541 load_seg->add_initial_output_data(segment_headers); 2542 if (phdr_seg != NULL) 2543 phdr_seg->add_initial_output_data(segment_headers); 2544 } 2545 2546 // Lay out the file header. 2547 if (load_seg != NULL) 2548 load_seg->add_initial_output_data(file_header); 2549 2550 if (this->script_options_->saw_phdrs_clause() 2551 && !parameters->options().relocatable()) 2552 { 2553 // Support use of FILEHDRS and PHDRS attachments in a PHDRS 2554 // clause in a linker script. 2555 Script_sections* ss = this->script_options_->script_sections(); 2556 ss->put_headers_in_phdrs(file_header, segment_headers); 2557 } 2558 2559 // We set the output section indexes in set_segment_offsets and 2560 // set_section_indexes. 2561 *pshndx = 1; 2562 2563 // Set the file offsets of all the segments, and all the sections 2564 // they contain. 2565 off_t off; 2566 if (!parameters->options().relocatable()) 2567 off = this->set_segment_offsets(target, load_seg, pshndx); 2568 else 2569 off = this->set_relocatable_section_offsets(file_header, pshndx); 2570 2571 // Verify that the dummy relaxation does not change anything. 2572 if (is_debugging_enabled(DEBUG_RELAXATION)) 2573 { 2574 if (pass == 0) 2575 this->relaxation_debug_check_->read_sections(this->section_list_); 2576 else 2577 this->relaxation_debug_check_->verify_sections(this->section_list_); 2578 } 2579 2580 *pload_seg = load_seg; 2581 return off; 2582 } 2583 2584 // Search the list of patterns and find the postion of the given section 2585 // name in the output section. If the section name matches a glob 2586 // pattern and a non-glob name, then the non-glob position takes 2587 // precedence. Return 0 if no match is found. 2588 2589 unsigned int 2590 Layout::find_section_order_index(const std::string& section_name) 2591 { 2592 Unordered_map<std::string, unsigned int>::iterator map_it; 2593 map_it = this->input_section_position_.find(section_name); 2594 if (map_it != this->input_section_position_.end()) 2595 return map_it->second; 2596 2597 // Absolute match failed. Linear search the glob patterns. 2598 std::vector<std::string>::iterator it; 2599 for (it = this->input_section_glob_.begin(); 2600 it != this->input_section_glob_.end(); 2601 ++it) 2602 { 2603 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0) 2604 { 2605 map_it = this->input_section_position_.find(*it); 2606 gold_assert(map_it != this->input_section_position_.end()); 2607 return map_it->second; 2608 } 2609 } 2610 return 0; 2611 } 2612 2613 // Read the sequence of input sections from the file specified with 2614 // option --section-ordering-file. 2615 2616 void 2617 Layout::read_layout_from_file() 2618 { 2619 const char* filename = parameters->options().section_ordering_file(); 2620 std::ifstream in; 2621 std::string line; 2622 2623 in.open(filename); 2624 if (!in) 2625 gold_fatal(_("unable to open --section-ordering-file file %s: %s"), 2626 filename, strerror(errno)); 2627 2628 std::getline(in, line); // this chops off the trailing \n, if any 2629 unsigned int position = 1; 2630 this->set_section_ordering_specified(); 2631 2632 while (in) 2633 { 2634 if (!line.empty() && line[line.length() - 1] == '\r') // Windows 2635 line.resize(line.length() - 1); 2636 // Ignore comments, beginning with '#' 2637 if (line[0] == '#') 2638 { 2639 std::getline(in, line); 2640 continue; 2641 } 2642 this->input_section_position_[line] = position; 2643 // Store all glob patterns in a vector. 2644 if (is_wildcard_string(line.c_str())) 2645 this->input_section_glob_.push_back(line); 2646 position++; 2647 std::getline(in, line); 2648 } 2649 } 2650 2651 // Finalize the layout. When this is called, we have created all the 2652 // output sections and all the output segments which are based on 2653 // input sections. We have several things to do, and we have to do 2654 // them in the right order, so that we get the right results correctly 2655 // and efficiently. 2656 2657 // 1) Finalize the list of output segments and create the segment 2658 // table header. 2659 2660 // 2) Finalize the dynamic symbol table and associated sections. 2661 2662 // 3) Determine the final file offset of all the output segments. 2663 2664 // 4) Determine the final file offset of all the SHF_ALLOC output 2665 // sections. 2666 2667 // 5) Create the symbol table sections and the section name table 2668 // section. 2669 2670 // 6) Finalize the symbol table: set symbol values to their final 2671 // value and make a final determination of which symbols are going 2672 // into the output symbol table. 2673 2674 // 7) Create the section table header. 2675 2676 // 8) Determine the final file offset of all the output sections which 2677 // are not SHF_ALLOC, including the section table header. 2678 2679 // 9) Finalize the ELF file header. 2680 2681 // This function returns the size of the output file. 2682 2683 off_t 2684 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, 2685 Target* target, const Task* task) 2686 { 2687 target->finalize_sections(this, input_objects, symtab); 2688 2689 this->count_local_symbols(task, input_objects); 2690 2691 this->link_stabs_sections(); 2692 2693 Output_segment* phdr_seg = NULL; 2694 if (!parameters->options().relocatable() && !parameters->doing_static_link()) 2695 { 2696 // There was a dynamic object in the link. We need to create 2697 // some information for the dynamic linker. 2698 2699 // Create the PT_PHDR segment which will hold the program 2700 // headers. 2701 if (!this->script_options_->saw_phdrs_clause()) 2702 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R); 2703 2704 // Create the dynamic symbol table, including the hash table. 2705 Output_section* dynstr; 2706 std::vector<Symbol*> dynamic_symbols; 2707 unsigned int local_dynamic_count; 2708 Versions versions(*this->script_options()->version_script_info(), 2709 &this->dynpool_); 2710 this->create_dynamic_symtab(input_objects, symtab, &dynstr, 2711 &local_dynamic_count, &dynamic_symbols, 2712 &versions); 2713 2714 // Create the .interp section to hold the name of the 2715 // interpreter, and put it in a PT_INTERP segment. Don't do it 2716 // if we saw a .interp section in an input file. 2717 if ((!parameters->options().shared() 2718 || parameters->options().dynamic_linker() != NULL) 2719 && this->interp_segment_ == NULL) 2720 this->create_interp(target); 2721 2722 // Finish the .dynamic section to hold the dynamic data, and put 2723 // it in a PT_DYNAMIC segment. 2724 this->finish_dynamic_section(input_objects, symtab); 2725 2726 // We should have added everything we need to the dynamic string 2727 // table. 2728 this->dynpool_.set_string_offsets(); 2729 2730 // Create the version sections. We can't do this until the 2731 // dynamic string table is complete. 2732 this->create_version_sections(&versions, symtab, local_dynamic_count, 2733 dynamic_symbols, dynstr); 2734 2735 // Set the size of the _DYNAMIC symbol. We can't do this until 2736 // after we call create_version_sections. 2737 this->set_dynamic_symbol_size(symtab); 2738 } 2739 2740 // Create segment headers. 2741 Output_segment_headers* segment_headers = 2742 (parameters->options().relocatable() 2743 ? NULL 2744 : new Output_segment_headers(this->segment_list_)); 2745 2746 // Lay out the file header. 2747 Output_file_header* file_header = new Output_file_header(target, symtab, 2748 segment_headers); 2749 2750 this->special_output_list_.push_back(file_header); 2751 if (segment_headers != NULL) 2752 this->special_output_list_.push_back(segment_headers); 2753 2754 // Find approriate places for orphan output sections if we are using 2755 // a linker script. 2756 if (this->script_options_->saw_sections_clause()) 2757 this->place_orphan_sections_in_script(); 2758 2759 Output_segment* load_seg; 2760 off_t off; 2761 unsigned int shndx; 2762 int pass = 0; 2763 2764 // Take a snapshot of the section layout as needed. 2765 if (target->may_relax()) 2766 this->prepare_for_relaxation(); 2767 2768 // Run the relaxation loop to lay out sections. 2769 do 2770 { 2771 off = this->relaxation_loop_body(pass, target, symtab, &load_seg, 2772 phdr_seg, segment_headers, file_header, 2773 &shndx); 2774 pass++; 2775 } 2776 while (target->may_relax() 2777 && target->relax(pass, input_objects, symtab, this, task)); 2778 2779 // If there is a load segment that contains the file and program headers, 2780 // provide a symbol __ehdr_start pointing there. 2781 // A program can use this to examine itself robustly. 2782 Symbol *ehdr_start = symtab->lookup("__ehdr_start"); 2783 if (ehdr_start != NULL && ehdr_start->is_predefined()) 2784 { 2785 if (load_seg != NULL) 2786 ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START); 2787 else 2788 ehdr_start->set_undefined(); 2789 } 2790 2791 // Set the file offsets of all the non-data sections we've seen so 2792 // far which don't have to wait for the input sections. We need 2793 // this in order to finalize local symbols in non-allocated 2794 // sections. 2795 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS); 2796 2797 // Set the section indexes of all unallocated sections seen so far, 2798 // in case any of them are somehow referenced by a symbol. 2799 shndx = this->set_section_indexes(shndx); 2800 2801 // Create the symbol table sections. 2802 this->create_symtab_sections(input_objects, symtab, shndx, &off); 2803 if (!parameters->doing_static_link()) 2804 this->assign_local_dynsym_offsets(input_objects); 2805 2806 // Process any symbol assignments from a linker script. This must 2807 // be called after the symbol table has been finalized. 2808 this->script_options_->finalize_symbols(symtab, this); 2809 2810 // Create the incremental inputs sections. 2811 if (this->incremental_inputs_) 2812 { 2813 this->incremental_inputs_->finalize(); 2814 this->create_incremental_info_sections(symtab); 2815 } 2816 2817 // Create the .shstrtab section. 2818 Output_section* shstrtab_section = this->create_shstrtab(); 2819 2820 // Set the file offsets of the rest of the non-data sections which 2821 // don't have to wait for the input sections. 2822 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS); 2823 2824 // Now that all sections have been created, set the section indexes 2825 // for any sections which haven't been done yet. 2826 shndx = this->set_section_indexes(shndx); 2827 2828 // Create the section table header. 2829 this->create_shdrs(shstrtab_section, &off); 2830 2831 // If there are no sections which require postprocessing, we can 2832 // handle the section names now, and avoid a resize later. 2833 if (!this->any_postprocessing_sections_) 2834 { 2835 off = this->set_section_offsets(off, 2836 POSTPROCESSING_SECTIONS_PASS); 2837 off = 2838 this->set_section_offsets(off, 2839 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS); 2840 } 2841 2842 file_header->set_section_info(this->section_headers_, shstrtab_section); 2843 2844 // Now we know exactly where everything goes in the output file 2845 // (except for non-allocated sections which require postprocessing). 2846 Output_data::layout_complete(); 2847 2848 this->output_file_size_ = off; 2849 2850 return off; 2851 } 2852 2853 // Create a note header following the format defined in the ELF ABI. 2854 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name 2855 // of the section to create, DESCSZ is the size of the descriptor. 2856 // ALLOCATE is true if the section should be allocated in memory. 2857 // This returns the new note section. It sets *TRAILING_PADDING to 2858 // the number of trailing zero bytes required. 2859 2860 Output_section* 2861 Layout::create_note(const char* name, int note_type, 2862 const char* section_name, size_t descsz, 2863 bool allocate, size_t* trailing_padding) 2864 { 2865 // Authorities all agree that the values in a .note field should 2866 // be aligned on 4-byte boundaries for 32-bit binaries. However, 2867 // they differ on what the alignment is for 64-bit binaries. 2868 // The GABI says unambiguously they take 8-byte alignment: 2869 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section 2870 // Other documentation says alignment should always be 4 bytes: 2871 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format 2872 // GNU ld and GNU readelf both support the latter (at least as of 2873 // version 2.16.91), and glibc always generates the latter for 2874 // .note.ABI-tag (as of version 1.6), so that's the one we go with 2875 // here. 2876 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default. 2877 const int size = parameters->target().get_size(); 2878 #else 2879 const int size = 32; 2880 #endif 2881 2882 // The contents of the .note section. 2883 size_t namesz = strlen(name) + 1; 2884 size_t aligned_namesz = align_address(namesz, size / 8); 2885 size_t aligned_descsz = align_address(descsz, size / 8); 2886 2887 size_t notehdrsz = 3 * (size / 8) + aligned_namesz; 2888 2889 unsigned char* buffer = new unsigned char[notehdrsz]; 2890 memset(buffer, 0, notehdrsz); 2891 2892 bool is_big_endian = parameters->target().is_big_endian(); 2893 2894 if (size == 32) 2895 { 2896 if (!is_big_endian) 2897 { 2898 elfcpp::Swap<32, false>::writeval(buffer, namesz); 2899 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz); 2900 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type); 2901 } 2902 else 2903 { 2904 elfcpp::Swap<32, true>::writeval(buffer, namesz); 2905 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz); 2906 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type); 2907 } 2908 } 2909 else if (size == 64) 2910 { 2911 if (!is_big_endian) 2912 { 2913 elfcpp::Swap<64, false>::writeval(buffer, namesz); 2914 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz); 2915 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type); 2916 } 2917 else 2918 { 2919 elfcpp::Swap<64, true>::writeval(buffer, namesz); 2920 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz); 2921 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type); 2922 } 2923 } 2924 else 2925 gold_unreachable(); 2926 2927 memcpy(buffer + 3 * (size / 8), name, namesz); 2928 2929 elfcpp::Elf_Xword flags = 0; 2930 Output_section_order order = ORDER_INVALID; 2931 if (allocate) 2932 { 2933 flags = elfcpp::SHF_ALLOC; 2934 order = ORDER_RO_NOTE; 2935 } 2936 Output_section* os = this->choose_output_section(NULL, section_name, 2937 elfcpp::SHT_NOTE, 2938 flags, false, order, false); 2939 if (os == NULL) 2940 return NULL; 2941 2942 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz, 2943 size / 8, 2944 "** note header"); 2945 os->add_output_section_data(posd); 2946 2947 *trailing_padding = aligned_descsz - descsz; 2948 2949 return os; 2950 } 2951 2952 // For an executable or shared library, create a note to record the 2953 // version of gold used to create the binary. 2954 2955 void 2956 Layout::create_gold_note() 2957 { 2958 if (parameters->options().relocatable() 2959 || parameters->incremental_update()) 2960 return; 2961 2962 std::string desc = std::string("gold ") + gold::get_version_string(); 2963 2964 size_t trailing_padding; 2965 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION, 2966 ".note.gnu.gold-version", desc.size(), 2967 false, &trailing_padding); 2968 if (os == NULL) 2969 return; 2970 2971 Output_section_data* posd = new Output_data_const(desc, 4); 2972 os->add_output_section_data(posd); 2973 2974 if (trailing_padding > 0) 2975 { 2976 posd = new Output_data_zero_fill(trailing_padding, 0); 2977 os->add_output_section_data(posd); 2978 } 2979 } 2980 2981 // Record whether the stack should be executable. This can be set 2982 // from the command line using the -z execstack or -z noexecstack 2983 // options. Otherwise, if any input file has a .note.GNU-stack 2984 // section with the SHF_EXECINSTR flag set, the stack should be 2985 // executable. Otherwise, if at least one input file a 2986 // .note.GNU-stack section, and some input file has no .note.GNU-stack 2987 // section, we use the target default for whether the stack should be 2988 // executable. Otherwise, we don't generate a stack note. When 2989 // generating a object file, we create a .note.GNU-stack section with 2990 // the appropriate marking. When generating an executable or shared 2991 // library, we create a PT_GNU_STACK segment. 2992 2993 void 2994 Layout::create_executable_stack_info() 2995 { 2996 bool is_stack_executable; 2997 if (parameters->options().is_execstack_set()) 2998 { 2999 is_stack_executable = parameters->options().is_stack_executable(); 3000 if (!is_stack_executable 3001 && this->input_requires_executable_stack_ 3002 && parameters->options().warn_execstack()) 3003 gold_warning(_("one or more inputs require executable stack, " 3004 "but -z noexecstack was given")); 3005 } 3006 else if (!this->input_with_gnu_stack_note_) 3007 return; 3008 else 3009 { 3010 if (this->input_requires_executable_stack_) 3011 is_stack_executable = true; 3012 else if (this->input_without_gnu_stack_note_) 3013 is_stack_executable = 3014 parameters->target().is_default_stack_executable(); 3015 else 3016 is_stack_executable = false; 3017 } 3018 3019 if (parameters->options().relocatable()) 3020 { 3021 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL); 3022 elfcpp::Elf_Xword flags = 0; 3023 if (is_stack_executable) 3024 flags |= elfcpp::SHF_EXECINSTR; 3025 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags, 3026 ORDER_INVALID, false); 3027 } 3028 else 3029 { 3030 if (this->script_options_->saw_phdrs_clause()) 3031 return; 3032 int flags = elfcpp::PF_R | elfcpp::PF_W; 3033 if (is_stack_executable) 3034 flags |= elfcpp::PF_X; 3035 this->make_output_segment(elfcpp::PT_GNU_STACK, flags); 3036 } 3037 } 3038 3039 // If --build-id was used, set up the build ID note. 3040 3041 void 3042 Layout::create_build_id() 3043 { 3044 if (!parameters->options().user_set_build_id()) 3045 return; 3046 3047 const char* style = parameters->options().build_id(); 3048 if (strcmp(style, "none") == 0) 3049 return; 3050 3051 // Set DESCSZ to the size of the note descriptor. When possible, 3052 // set DESC to the note descriptor contents. 3053 size_t descsz; 3054 std::string desc; 3055 if (strcmp(style, "md5") == 0) 3056 descsz = 128 / 8; 3057 else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) 3058 descsz = 160 / 8; 3059 else if (strcmp(style, "uuid") == 0) 3060 { 3061 const size_t uuidsz = 128 / 8; 3062 3063 char buffer[uuidsz]; 3064 memset(buffer, 0, uuidsz); 3065 3066 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY); 3067 if (descriptor < 0) 3068 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"), 3069 strerror(errno)); 3070 else 3071 { 3072 ssize_t got = ::read(descriptor, buffer, uuidsz); 3073 release_descriptor(descriptor, true); 3074 if (got < 0) 3075 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno)); 3076 else if (static_cast<size_t>(got) != uuidsz) 3077 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"), 3078 uuidsz, got); 3079 } 3080 3081 desc.assign(buffer, uuidsz); 3082 descsz = uuidsz; 3083 } 3084 else if (strncmp(style, "0x", 2) == 0) 3085 { 3086 hex_init(); 3087 const char* p = style + 2; 3088 while (*p != '\0') 3089 { 3090 if (hex_p(p[0]) && hex_p(p[1])) 3091 { 3092 char c = (hex_value(p[0]) << 4) | hex_value(p[1]); 3093 desc += c; 3094 p += 2; 3095 } 3096 else if (*p == '-' || *p == ':') 3097 ++p; 3098 else 3099 gold_fatal(_("--build-id argument '%s' not a valid hex number"), 3100 style); 3101 } 3102 descsz = desc.size(); 3103 } 3104 else 3105 gold_fatal(_("unrecognized --build-id argument '%s'"), style); 3106 3107 // Create the note. 3108 size_t trailing_padding; 3109 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID, 3110 ".note.gnu.build-id", descsz, true, 3111 &trailing_padding); 3112 if (os == NULL) 3113 return; 3114 3115 if (!desc.empty()) 3116 { 3117 // We know the value already, so we fill it in now. 3118 gold_assert(desc.size() == descsz); 3119 3120 Output_section_data* posd = new Output_data_const(desc, 4); 3121 os->add_output_section_data(posd); 3122 3123 if (trailing_padding != 0) 3124 { 3125 posd = new Output_data_zero_fill(trailing_padding, 0); 3126 os->add_output_section_data(posd); 3127 } 3128 } 3129 else 3130 { 3131 // We need to compute a checksum after we have completed the 3132 // link. 3133 gold_assert(trailing_padding == 0); 3134 this->build_id_note_ = new Output_data_zero_fill(descsz, 4); 3135 os->add_output_section_data(this->build_id_note_); 3136 } 3137 } 3138 3139 // If we have both .stabXX and .stabXXstr sections, then the sh_link 3140 // field of the former should point to the latter. I'm not sure who 3141 // started this, but the GNU linker does it, and some tools depend 3142 // upon it. 3143 3144 void 3145 Layout::link_stabs_sections() 3146 { 3147 if (!this->have_stabstr_section_) 3148 return; 3149 3150 for (Section_list::iterator p = this->section_list_.begin(); 3151 p != this->section_list_.end(); 3152 ++p) 3153 { 3154 if ((*p)->type() != elfcpp::SHT_STRTAB) 3155 continue; 3156 3157 const char* name = (*p)->name(); 3158 if (strncmp(name, ".stab", 5) != 0) 3159 continue; 3160 3161 size_t len = strlen(name); 3162 if (strcmp(name + len - 3, "str") != 0) 3163 continue; 3164 3165 std::string stab_name(name, len - 3); 3166 Output_section* stab_sec; 3167 stab_sec = this->find_output_section(stab_name.c_str()); 3168 if (stab_sec != NULL) 3169 stab_sec->set_link_section(*p); 3170 } 3171 } 3172 3173 // Create .gnu_incremental_inputs and related sections needed 3174 // for the next run of incremental linking to check what has changed. 3175 3176 void 3177 Layout::create_incremental_info_sections(Symbol_table* symtab) 3178 { 3179 Incremental_inputs* incr = this->incremental_inputs_; 3180 3181 gold_assert(incr != NULL); 3182 3183 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections. 3184 incr->create_data_sections(symtab); 3185 3186 // Add the .gnu_incremental_inputs section. 3187 const char* incremental_inputs_name = 3188 this->namepool_.add(".gnu_incremental_inputs", false, NULL); 3189 Output_section* incremental_inputs_os = 3190 this->make_output_section(incremental_inputs_name, 3191 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0, 3192 ORDER_INVALID, false); 3193 incremental_inputs_os->add_output_section_data(incr->inputs_section()); 3194 3195 // Add the .gnu_incremental_symtab section. 3196 const char* incremental_symtab_name = 3197 this->namepool_.add(".gnu_incremental_symtab", false, NULL); 3198 Output_section* incremental_symtab_os = 3199 this->make_output_section(incremental_symtab_name, 3200 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0, 3201 ORDER_INVALID, false); 3202 incremental_symtab_os->add_output_section_data(incr->symtab_section()); 3203 incremental_symtab_os->set_entsize(4); 3204 3205 // Add the .gnu_incremental_relocs section. 3206 const char* incremental_relocs_name = 3207 this->namepool_.add(".gnu_incremental_relocs", false, NULL); 3208 Output_section* incremental_relocs_os = 3209 this->make_output_section(incremental_relocs_name, 3210 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0, 3211 ORDER_INVALID, false); 3212 incremental_relocs_os->add_output_section_data(incr->relocs_section()); 3213 incremental_relocs_os->set_entsize(incr->relocs_entsize()); 3214 3215 // Add the .gnu_incremental_got_plt section. 3216 const char* incremental_got_plt_name = 3217 this->namepool_.add(".gnu_incremental_got_plt", false, NULL); 3218 Output_section* incremental_got_plt_os = 3219 this->make_output_section(incremental_got_plt_name, 3220 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0, 3221 ORDER_INVALID, false); 3222 incremental_got_plt_os->add_output_section_data(incr->got_plt_section()); 3223 3224 // Add the .gnu_incremental_strtab section. 3225 const char* incremental_strtab_name = 3226 this->namepool_.add(".gnu_incremental_strtab", false, NULL); 3227 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name, 3228 elfcpp::SHT_STRTAB, 0, 3229 ORDER_INVALID, false); 3230 Output_data_strtab* strtab_data = 3231 new Output_data_strtab(incr->get_stringpool()); 3232 incremental_strtab_os->add_output_section_data(strtab_data); 3233 3234 incremental_inputs_os->set_after_input_sections(); 3235 incremental_symtab_os->set_after_input_sections(); 3236 incremental_relocs_os->set_after_input_sections(); 3237 incremental_got_plt_os->set_after_input_sections(); 3238 3239 incremental_inputs_os->set_link_section(incremental_strtab_os); 3240 incremental_symtab_os->set_link_section(incremental_inputs_os); 3241 incremental_relocs_os->set_link_section(incremental_inputs_os); 3242 incremental_got_plt_os->set_link_section(incremental_inputs_os); 3243 } 3244 3245 // Return whether SEG1 should be before SEG2 in the output file. This 3246 // is based entirely on the segment type and flags. When this is 3247 // called the segment addresses have normally not yet been set. 3248 3249 bool 3250 Layout::segment_precedes(const Output_segment* seg1, 3251 const Output_segment* seg2) 3252 { 3253 elfcpp::Elf_Word type1 = seg1->type(); 3254 elfcpp::Elf_Word type2 = seg2->type(); 3255 3256 // The single PT_PHDR segment is required to precede any loadable 3257 // segment. We simply make it always first. 3258 if (type1 == elfcpp::PT_PHDR) 3259 { 3260 gold_assert(type2 != elfcpp::PT_PHDR); 3261 return true; 3262 } 3263 if (type2 == elfcpp::PT_PHDR) 3264 return false; 3265 3266 // The single PT_INTERP segment is required to precede any loadable 3267 // segment. We simply make it always second. 3268 if (type1 == elfcpp::PT_INTERP) 3269 { 3270 gold_assert(type2 != elfcpp::PT_INTERP); 3271 return true; 3272 } 3273 if (type2 == elfcpp::PT_INTERP) 3274 return false; 3275 3276 // We then put PT_LOAD segments before any other segments. 3277 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD) 3278 return true; 3279 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD) 3280 return false; 3281 3282 // We put the PT_TLS segment last except for the PT_GNU_RELRO 3283 // segment, because that is where the dynamic linker expects to find 3284 // it (this is just for efficiency; other positions would also work 3285 // correctly). 3286 if (type1 == elfcpp::PT_TLS 3287 && type2 != elfcpp::PT_TLS 3288 && type2 != elfcpp::PT_GNU_RELRO) 3289 return false; 3290 if (type2 == elfcpp::PT_TLS 3291 && type1 != elfcpp::PT_TLS 3292 && type1 != elfcpp::PT_GNU_RELRO) 3293 return true; 3294 3295 // We put the PT_GNU_RELRO segment last, because that is where the 3296 // dynamic linker expects to find it (as with PT_TLS, this is just 3297 // for efficiency). 3298 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO) 3299 return false; 3300 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO) 3301 return true; 3302 3303 const elfcpp::Elf_Word flags1 = seg1->flags(); 3304 const elfcpp::Elf_Word flags2 = seg2->flags(); 3305 3306 // The order of non-PT_LOAD segments is unimportant. We simply sort 3307 // by the numeric segment type and flags values. There should not 3308 // be more than one segment with the same type and flags, except 3309 // when a linker script specifies such. 3310 if (type1 != elfcpp::PT_LOAD) 3311 { 3312 if (type1 != type2) 3313 return type1 < type2; 3314 gold_assert(flags1 != flags2 3315 || this->script_options_->saw_phdrs_clause()); 3316 return flags1 < flags2; 3317 } 3318 3319 // If the addresses are set already, sort by load address. 3320 if (seg1->are_addresses_set()) 3321 { 3322 if (!seg2->are_addresses_set()) 3323 return true; 3324 3325 unsigned int section_count1 = seg1->output_section_count(); 3326 unsigned int section_count2 = seg2->output_section_count(); 3327 if (section_count1 == 0 && section_count2 > 0) 3328 return true; 3329 if (section_count1 > 0 && section_count2 == 0) 3330 return false; 3331 3332 uint64_t paddr1 = (seg1->are_addresses_set() 3333 ? seg1->paddr() 3334 : seg1->first_section_load_address()); 3335 uint64_t paddr2 = (seg2->are_addresses_set() 3336 ? seg2->paddr() 3337 : seg2->first_section_load_address()); 3338 3339 if (paddr1 != paddr2) 3340 return paddr1 < paddr2; 3341 } 3342 else if (seg2->are_addresses_set()) 3343 return false; 3344 3345 // A segment which holds large data comes after a segment which does 3346 // not hold large data. 3347 if (seg1->is_large_data_segment()) 3348 { 3349 if (!seg2->is_large_data_segment()) 3350 return false; 3351 } 3352 else if (seg2->is_large_data_segment()) 3353 return true; 3354 3355 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly 3356 // segments come before writable segments. Then writable segments 3357 // with data come before writable segments without data. Then 3358 // executable segments come before non-executable segments. Then 3359 // the unlikely case of a non-readable segment comes before the 3360 // normal case of a readable segment. If there are multiple 3361 // segments with the same type and flags, we require that the 3362 // address be set, and we sort by virtual address and then physical 3363 // address. 3364 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W)) 3365 return (flags1 & elfcpp::PF_W) == 0; 3366 if ((flags1 & elfcpp::PF_W) != 0 3367 && seg1->has_any_data_sections() != seg2->has_any_data_sections()) 3368 return seg1->has_any_data_sections(); 3369 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X)) 3370 return (flags1 & elfcpp::PF_X) != 0; 3371 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R)) 3372 return (flags1 & elfcpp::PF_R) == 0; 3373 3374 // We shouldn't get here--we shouldn't create segments which we 3375 // can't distinguish. Unless of course we are using a weird linker 3376 // script or overlapping --section-start options. We could also get 3377 // here if plugins want unique segments for subsets of sections. 3378 gold_assert(this->script_options_->saw_phdrs_clause() 3379 || parameters->options().any_section_start() 3380 || this->is_unique_segment_for_sections_specified()); 3381 return false; 3382 } 3383 3384 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE. 3385 3386 static off_t 3387 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize) 3388 { 3389 uint64_t unsigned_off = off; 3390 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1)) 3391 | (addr & (abi_pagesize - 1))); 3392 if (aligned_off < unsigned_off) 3393 aligned_off += abi_pagesize; 3394 return aligned_off; 3395 } 3396 3397 // On targets where the text segment contains only executable code, 3398 // a non-executable segment is never the text segment. 3399 3400 static inline bool 3401 is_text_segment(const Target* target, const Output_segment* seg) 3402 { 3403 elfcpp::Elf_Xword flags = seg->flags(); 3404 if ((flags & elfcpp::PF_W) != 0) 3405 return false; 3406 if ((flags & elfcpp::PF_X) == 0) 3407 return !target->isolate_execinstr(); 3408 return true; 3409 } 3410 3411 // Set the file offsets of all the segments, and all the sections they 3412 // contain. They have all been created. LOAD_SEG must be be laid out 3413 // first. Return the offset of the data to follow. 3414 3415 off_t 3416 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, 3417 unsigned int* pshndx) 3418 { 3419 // Sort them into the final order. We use a stable sort so that we 3420 // don't randomize the order of indistinguishable segments created 3421 // by linker scripts. 3422 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(), 3423 Layout::Compare_segments(this)); 3424 3425 // Find the PT_LOAD segments, and set their addresses and offsets 3426 // and their section's addresses and offsets. 3427 uint64_t start_addr; 3428 if (parameters->options().user_set_Ttext()) 3429 start_addr = parameters->options().Ttext(); 3430 else if (parameters->options().output_is_position_independent()) 3431 start_addr = 0; 3432 else 3433 start_addr = target->default_text_segment_address(); 3434 3435 uint64_t addr = start_addr; 3436 off_t off = 0; 3437 3438 // If LOAD_SEG is NULL, then the file header and segment headers 3439 // will not be loadable. But they still need to be at offset 0 in 3440 // the file. Set their offsets now. 3441 if (load_seg == NULL) 3442 { 3443 for (Data_list::iterator p = this->special_output_list_.begin(); 3444 p != this->special_output_list_.end(); 3445 ++p) 3446 { 3447 off = align_address(off, (*p)->addralign()); 3448 (*p)->set_address_and_file_offset(0, off); 3449 off += (*p)->data_size(); 3450 } 3451 } 3452 3453 unsigned int increase_relro = this->increase_relro_; 3454 if (this->script_options_->saw_sections_clause()) 3455 increase_relro = 0; 3456 3457 const bool check_sections = parameters->options().check_sections(); 3458 Output_segment* last_load_segment = NULL; 3459 3460 unsigned int shndx_begin = *pshndx; 3461 unsigned int shndx_load_seg = *pshndx; 3462 3463 for (Segment_list::iterator p = this->segment_list_.begin(); 3464 p != this->segment_list_.end(); 3465 ++p) 3466 { 3467 if ((*p)->type() == elfcpp::PT_LOAD) 3468 { 3469 if (target->isolate_execinstr()) 3470 { 3471 // When we hit the segment that should contain the 3472 // file headers, reset the file offset so we place 3473 // it and subsequent segments appropriately. 3474 // We'll fix up the preceding segments below. 3475 if (load_seg == *p) 3476 { 3477 if (off == 0) 3478 load_seg = NULL; 3479 else 3480 { 3481 off = 0; 3482 shndx_load_seg = *pshndx; 3483 } 3484 } 3485 } 3486 else 3487 { 3488 // Verify that the file headers fall into the first segment. 3489 if (load_seg != NULL && load_seg != *p) 3490 gold_unreachable(); 3491 load_seg = NULL; 3492 } 3493 3494 bool are_addresses_set = (*p)->are_addresses_set(); 3495 if (are_addresses_set) 3496 { 3497 // When it comes to setting file offsets, we care about 3498 // the physical address. 3499 addr = (*p)->paddr(); 3500 } 3501 else if (parameters->options().user_set_Ttext() 3502 && (parameters->options().omagic() 3503 || is_text_segment(target, *p))) 3504 { 3505 are_addresses_set = true; 3506 } 3507 else if (parameters->options().user_set_Trodata_segment() 3508 && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0) 3509 { 3510 addr = parameters->options().Trodata_segment(); 3511 are_addresses_set = true; 3512 } 3513 else if (parameters->options().user_set_Tdata() 3514 && ((*p)->flags() & elfcpp::PF_W) != 0 3515 && (!parameters->options().user_set_Tbss() 3516 || (*p)->has_any_data_sections())) 3517 { 3518 addr = parameters->options().Tdata(); 3519 are_addresses_set = true; 3520 } 3521 else if (parameters->options().user_set_Tbss() 3522 && ((*p)->flags() & elfcpp::PF_W) != 0 3523 && !(*p)->has_any_data_sections()) 3524 { 3525 addr = parameters->options().Tbss(); 3526 are_addresses_set = true; 3527 } 3528 3529 uint64_t orig_addr = addr; 3530 uint64_t orig_off = off; 3531 3532 uint64_t aligned_addr = 0; 3533 uint64_t abi_pagesize = target->abi_pagesize(); 3534 uint64_t common_pagesize = target->common_pagesize(); 3535 3536 if (!parameters->options().nmagic() 3537 && !parameters->options().omagic()) 3538 (*p)->set_minimum_p_align(abi_pagesize); 3539 3540 if (!are_addresses_set) 3541 { 3542 // Skip the address forward one page, maintaining the same 3543 // position within the page. This lets us store both segments 3544 // overlapping on a single page in the file, but the loader will 3545 // put them on different pages in memory. We will revisit this 3546 // decision once we know the size of the segment. 3547 3548 uint64_t max_align = (*p)->maximum_alignment(); 3549 if (max_align > abi_pagesize) 3550 addr = align_address(addr, max_align); 3551 aligned_addr = addr; 3552 3553 if (load_seg == *p) 3554 { 3555 // This is the segment that will contain the file 3556 // headers, so its offset will have to be exactly zero. 3557 gold_assert(orig_off == 0); 3558 3559 // If the target wants a fixed minimum distance from the 3560 // text segment to the read-only segment, move up now. 3561 uint64_t min_addr = 3562 start_addr + (parameters->options().user_set_rosegment_gap() 3563 ? parameters->options().rosegment_gap() 3564 : target->rosegment_gap()); 3565 if (addr < min_addr) 3566 addr = min_addr; 3567 3568 // But this is not the first segment! To make its 3569 // address congruent with its offset, that address better 3570 // be aligned to the ABI-mandated page size. 3571 addr = align_address(addr, abi_pagesize); 3572 aligned_addr = addr; 3573 } 3574 else 3575 { 3576 if ((addr & (abi_pagesize - 1)) != 0) 3577 addr = addr + abi_pagesize; 3578 3579 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); 3580 } 3581 } 3582 3583 if (!parameters->options().nmagic() 3584 && !parameters->options().omagic()) 3585 { 3586 // Here we are also taking care of the case when 3587 // the maximum segment alignment is larger than the page size. 3588 off = align_file_offset(off, addr, 3589 std::max(abi_pagesize, 3590 (*p)->maximum_alignment())); 3591 } 3592 else 3593 { 3594 // This is -N or -n with a section script which prevents 3595 // us from using a load segment. We need to ensure that 3596 // the file offset is aligned to the alignment of the 3597 // segment. This is because the linker script 3598 // implicitly assumed a zero offset. If we don't align 3599 // here, then the alignment of the sections in the 3600 // linker script may not match the alignment of the 3601 // sections in the set_section_addresses call below, 3602 // causing an error about dot moving backward. 3603 off = align_address(off, (*p)->maximum_alignment()); 3604 } 3605 3606 unsigned int shndx_hold = *pshndx; 3607 bool has_relro = false; 3608 uint64_t new_addr = (*p)->set_section_addresses(target, this, 3609 false, addr, 3610 &increase_relro, 3611 &has_relro, 3612 &off, pshndx); 3613 3614 // Now that we know the size of this segment, we may be able 3615 // to save a page in memory, at the cost of wasting some 3616 // file space, by instead aligning to the start of a new 3617 // page. Here we use the real machine page size rather than 3618 // the ABI mandated page size. If the segment has been 3619 // aligned so that the relro data ends at a page boundary, 3620 // we do not try to realign it. 3621 3622 if (!are_addresses_set 3623 && !has_relro 3624 && aligned_addr != addr 3625 && !parameters->incremental()) 3626 { 3627 uint64_t first_off = (common_pagesize 3628 - (aligned_addr 3629 & (common_pagesize - 1))); 3630 uint64_t last_off = new_addr & (common_pagesize - 1); 3631 if (first_off > 0 3632 && last_off > 0 3633 && ((aligned_addr & ~ (common_pagesize - 1)) 3634 != (new_addr & ~ (common_pagesize - 1))) 3635 && first_off + last_off <= common_pagesize) 3636 { 3637 *pshndx = shndx_hold; 3638 addr = align_address(aligned_addr, common_pagesize); 3639 addr = align_address(addr, (*p)->maximum_alignment()); 3640 if ((addr & (abi_pagesize - 1)) != 0) 3641 addr = addr + abi_pagesize; 3642 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); 3643 off = align_file_offset(off, addr, abi_pagesize); 3644 3645 increase_relro = this->increase_relro_; 3646 if (this->script_options_->saw_sections_clause()) 3647 increase_relro = 0; 3648 has_relro = false; 3649 3650 new_addr = (*p)->set_section_addresses(target, this, 3651 true, addr, 3652 &increase_relro, 3653 &has_relro, 3654 &off, pshndx); 3655 } 3656 } 3657 3658 addr = new_addr; 3659 3660 // Implement --check-sections. We know that the segments 3661 // are sorted by LMA. 3662 if (check_sections && last_load_segment != NULL) 3663 { 3664 gold_assert(last_load_segment->paddr() <= (*p)->paddr()); 3665 if (last_load_segment->paddr() + last_load_segment->memsz() 3666 > (*p)->paddr()) 3667 { 3668 unsigned long long lb1 = last_load_segment->paddr(); 3669 unsigned long long le1 = lb1 + last_load_segment->memsz(); 3670 unsigned long long lb2 = (*p)->paddr(); 3671 unsigned long long le2 = lb2 + (*p)->memsz(); 3672 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and " 3673 "[0x%llx -> 0x%llx]"), 3674 lb1, le1, lb2, le2); 3675 } 3676 } 3677 last_load_segment = *p; 3678 } 3679 } 3680 3681 if (load_seg != NULL && target->isolate_execinstr()) 3682 { 3683 // Process the early segments again, setting their file offsets 3684 // so they land after the segments starting at LOAD_SEG. 3685 off = align_file_offset(off, 0, target->abi_pagesize()); 3686 3687 this->reset_relax_output(); 3688 3689 for (Segment_list::iterator p = this->segment_list_.begin(); 3690 *p != load_seg; 3691 ++p) 3692 { 3693 if ((*p)->type() == elfcpp::PT_LOAD) 3694 { 3695 // We repeat the whole job of assigning addresses and 3696 // offsets, but we really only want to change the offsets and 3697 // must ensure that the addresses all come out the same as 3698 // they did the first time through. 3699 bool has_relro = false; 3700 const uint64_t old_addr = (*p)->vaddr(); 3701 const uint64_t old_end = old_addr + (*p)->memsz(); 3702 uint64_t new_addr = (*p)->set_section_addresses(target, this, 3703 true, old_addr, 3704 &increase_relro, 3705 &has_relro, 3706 &off, 3707 &shndx_begin); 3708 gold_assert(new_addr == old_end); 3709 } 3710 } 3711 3712 gold_assert(shndx_begin == shndx_load_seg); 3713 } 3714 3715 // Handle the non-PT_LOAD segments, setting their offsets from their 3716 // section's offsets. 3717 for (Segment_list::iterator p = this->segment_list_.begin(); 3718 p != this->segment_list_.end(); 3719 ++p) 3720 { 3721 if ((*p)->type() != elfcpp::PT_LOAD) 3722 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO 3723 ? increase_relro 3724 : 0); 3725 } 3726 3727 // Set the TLS offsets for each section in the PT_TLS segment. 3728 if (this->tls_segment_ != NULL) 3729 this->tls_segment_->set_tls_offsets(); 3730 3731 return off; 3732 } 3733 3734 // Set the offsets of all the allocated sections when doing a 3735 // relocatable link. This does the same jobs as set_segment_offsets, 3736 // only for a relocatable link. 3737 3738 off_t 3739 Layout::set_relocatable_section_offsets(Output_data* file_header, 3740 unsigned int* pshndx) 3741 { 3742 off_t off = 0; 3743 3744 file_header->set_address_and_file_offset(0, 0); 3745 off += file_header->data_size(); 3746 3747 for (Section_list::iterator p = this->section_list_.begin(); 3748 p != this->section_list_.end(); 3749 ++p) 3750 { 3751 // We skip unallocated sections here, except that group sections 3752 // have to come first. 3753 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0 3754 && (*p)->type() != elfcpp::SHT_GROUP) 3755 continue; 3756 3757 off = align_address(off, (*p)->addralign()); 3758 3759 // The linker script might have set the address. 3760 if (!(*p)->is_address_valid()) 3761 (*p)->set_address(0); 3762 (*p)->set_file_offset(off); 3763 (*p)->finalize_data_size(); 3764 if ((*p)->type() != elfcpp::SHT_NOBITS) 3765 off += (*p)->data_size(); 3766 3767 (*p)->set_out_shndx(*pshndx); 3768 ++*pshndx; 3769 } 3770 3771 return off; 3772 } 3773 3774 // Set the file offset of all the sections not associated with a 3775 // segment. 3776 3777 off_t 3778 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass) 3779 { 3780 off_t startoff = off; 3781 off_t maxoff = off; 3782 3783 for (Section_list::iterator p = this->unattached_section_list_.begin(); 3784 p != this->unattached_section_list_.end(); 3785 ++p) 3786 { 3787 // The symtab section is handled in create_symtab_sections. 3788 if (*p == this->symtab_section_) 3789 continue; 3790 3791 // If we've already set the data size, don't set it again. 3792 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid()) 3793 continue; 3794 3795 if (pass == BEFORE_INPUT_SECTIONS_PASS 3796 && (*p)->requires_postprocessing()) 3797 { 3798 (*p)->create_postprocessing_buffer(); 3799 this->any_postprocessing_sections_ = true; 3800 } 3801 3802 if (pass == BEFORE_INPUT_SECTIONS_PASS 3803 && (*p)->after_input_sections()) 3804 continue; 3805 else if (pass == POSTPROCESSING_SECTIONS_PASS 3806 && (!(*p)->after_input_sections() 3807 || (*p)->type() == elfcpp::SHT_STRTAB)) 3808 continue; 3809 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS 3810 && (!(*p)->after_input_sections() 3811 || (*p)->type() != elfcpp::SHT_STRTAB)) 3812 continue; 3813 3814 if (!parameters->incremental_update()) 3815 { 3816 off = align_address(off, (*p)->addralign()); 3817 (*p)->set_file_offset(off); 3818 (*p)->finalize_data_size(); 3819 } 3820 else 3821 { 3822 // Incremental update: allocate file space from free list. 3823 (*p)->pre_finalize_data_size(); 3824 off_t current_size = (*p)->current_data_size(); 3825 off = this->allocate(current_size, (*p)->addralign(), startoff); 3826 if (off == -1) 3827 { 3828 if (is_debugging_enabled(DEBUG_INCREMENTAL)) 3829 this->free_list_.dump(); 3830 gold_assert((*p)->output_section() != NULL); 3831 gold_fallback(_("out of patch space for section %s; " 3832 "relink with --incremental-full"), 3833 (*p)->output_section()->name()); 3834 } 3835 (*p)->set_file_offset(off); 3836 (*p)->finalize_data_size(); 3837 if ((*p)->data_size() > current_size) 3838 { 3839 gold_assert((*p)->output_section() != NULL); 3840 gold_fallback(_("%s: section changed size; " 3841 "relink with --incremental-full"), 3842 (*p)->output_section()->name()); 3843 } 3844 gold_debug(DEBUG_INCREMENTAL, 3845 "set_section_offsets: %08lx %08lx %s", 3846 static_cast<long>(off), 3847 static_cast<long>((*p)->data_size()), 3848 ((*p)->output_section() != NULL 3849 ? (*p)->output_section()->name() : "(special)")); 3850 } 3851 3852 off += (*p)->data_size(); 3853 if (off > maxoff) 3854 maxoff = off; 3855 3856 // At this point the name must be set. 3857 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS) 3858 this->namepool_.add((*p)->name(), false, NULL); 3859 } 3860 return maxoff; 3861 } 3862 3863 // Set the section indexes of all the sections not associated with a 3864 // segment. 3865 3866 unsigned int 3867 Layout::set_section_indexes(unsigned int shndx) 3868 { 3869 for (Section_list::iterator p = this->unattached_section_list_.begin(); 3870 p != this->unattached_section_list_.end(); 3871 ++p) 3872 { 3873 if (!(*p)->has_out_shndx()) 3874 { 3875 (*p)->set_out_shndx(shndx); 3876 ++shndx; 3877 } 3878 } 3879 return shndx; 3880 } 3881 3882 // Set the section addresses according to the linker script. This is 3883 // only called when we see a SECTIONS clause. This returns the 3884 // program segment which should hold the file header and segment 3885 // headers, if any. It will return NULL if they should not be in a 3886 // segment. 3887 3888 Output_segment* 3889 Layout::set_section_addresses_from_script(Symbol_table* symtab) 3890 { 3891 Script_sections* ss = this->script_options_->script_sections(); 3892 gold_assert(ss->saw_sections_clause()); 3893 return this->script_options_->set_section_addresses(symtab, this); 3894 } 3895 3896 // Place the orphan sections in the linker script. 3897 3898 void 3899 Layout::place_orphan_sections_in_script() 3900 { 3901 Script_sections* ss = this->script_options_->script_sections(); 3902 gold_assert(ss->saw_sections_clause()); 3903 3904 // Place each orphaned output section in the script. 3905 for (Section_list::iterator p = this->section_list_.begin(); 3906 p != this->section_list_.end(); 3907 ++p) 3908 { 3909 if (!(*p)->found_in_sections_clause()) 3910 ss->place_orphan(*p); 3911 } 3912 } 3913 3914 // Count the local symbols in the regular symbol table and the dynamic 3915 // symbol table, and build the respective string pools. 3916 3917 void 3918 Layout::count_local_symbols(const Task* task, 3919 const Input_objects* input_objects) 3920 { 3921 // First, figure out an upper bound on the number of symbols we'll 3922 // be inserting into each pool. This helps us create the pools with 3923 // the right size, to avoid unnecessary hashtable resizing. 3924 unsigned int symbol_count = 0; 3925 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); 3926 p != input_objects->relobj_end(); 3927 ++p) 3928 symbol_count += (*p)->local_symbol_count(); 3929 3930 // Go from "upper bound" to "estimate." We overcount for two 3931 // reasons: we double-count symbols that occur in more than one 3932 // object file, and we count symbols that are dropped from the 3933 // output. Add it all together and assume we overcount by 100%. 3934 symbol_count /= 2; 3935 3936 // We assume all symbols will go into both the sympool and dynpool. 3937 this->sympool_.reserve(symbol_count); 3938 this->dynpool_.reserve(symbol_count); 3939 3940 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); 3941 p != input_objects->relobj_end(); 3942 ++p) 3943 { 3944 Task_lock_obj<Object> tlo(task, *p); 3945 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_); 3946 } 3947 } 3948 3949 // Create the symbol table sections. Here we also set the final 3950 // values of the symbols. At this point all the loadable sections are 3951 // fully laid out. SHNUM is the number of sections so far. 3952 3953 void 3954 Layout::create_symtab_sections(const Input_objects* input_objects, 3955 Symbol_table* symtab, 3956 unsigned int shnum, 3957 off_t* poff) 3958 { 3959 int symsize; 3960 unsigned int align; 3961 if (parameters->target().get_size() == 32) 3962 { 3963 symsize = elfcpp::Elf_sizes<32>::sym_size; 3964 align = 4; 3965 } 3966 else if (parameters->target().get_size() == 64) 3967 { 3968 symsize = elfcpp::Elf_sizes<64>::sym_size; 3969 align = 8; 3970 } 3971 else 3972 gold_unreachable(); 3973 3974 // Compute file offsets relative to the start of the symtab section. 3975 off_t off = 0; 3976 3977 // Save space for the dummy symbol at the start of the section. We 3978 // never bother to write this out--it will just be left as zero. 3979 off += symsize; 3980 unsigned int local_symbol_index = 1; 3981 3982 // Add STT_SECTION symbols for each Output section which needs one. 3983 for (Section_list::iterator p = this->section_list_.begin(); 3984 p != this->section_list_.end(); 3985 ++p) 3986 { 3987 if (!(*p)->needs_symtab_index()) 3988 (*p)->set_symtab_index(-1U); 3989 else 3990 { 3991 (*p)->set_symtab_index(local_symbol_index); 3992 ++local_symbol_index; 3993 off += symsize; 3994 } 3995 } 3996 3997 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); 3998 p != input_objects->relobj_end(); 3999 ++p) 4000 { 4001 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index, 4002 off, symtab); 4003 off += (index - local_symbol_index) * symsize; 4004 local_symbol_index = index; 4005 } 4006 4007 unsigned int local_symcount = local_symbol_index; 4008 gold_assert(static_cast<off_t>(local_symcount * symsize) == off); 4009 4010 off_t dynoff; 4011 size_t dyn_global_index; 4012 size_t dyncount; 4013 if (this->dynsym_section_ == NULL) 4014 { 4015 dynoff = 0; 4016 dyn_global_index = 0; 4017 dyncount = 0; 4018 } 4019 else 4020 { 4021 dyn_global_index = this->dynsym_section_->info(); 4022 off_t locsize = dyn_global_index * this->dynsym_section_->entsize(); 4023 dynoff = this->dynsym_section_->offset() + locsize; 4024 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize; 4025 gold_assert(static_cast<off_t>(dyncount * symsize) 4026 == this->dynsym_section_->data_size() - locsize); 4027 } 4028 4029 off_t global_off = off; 4030 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount, 4031 &this->sympool_, &local_symcount); 4032 4033 if (!parameters->options().strip_all()) 4034 { 4035 this->sympool_.set_string_offsets(); 4036 4037 const char* symtab_name = this->namepool_.add(".symtab", false, NULL); 4038 Output_section* osymtab = this->make_output_section(symtab_name, 4039 elfcpp::SHT_SYMTAB, 4040 0, ORDER_INVALID, 4041 false); 4042 this->symtab_section_ = osymtab; 4043 4044 Output_section_data* pos = new Output_data_fixed_space(off, align, 4045 "** symtab"); 4046 osymtab->add_output_section_data(pos); 4047 4048 // We generate a .symtab_shndx section if we have more than 4049 // SHN_LORESERVE sections. Technically it is possible that we 4050 // don't need one, because it is possible that there are no 4051 // symbols in any of sections with indexes larger than 4052 // SHN_LORESERVE. That is probably unusual, though, and it is 4053 // easier to always create one than to compute section indexes 4054 // twice (once here, once when writing out the symbols). 4055 if (shnum >= elfcpp::SHN_LORESERVE) 4056 { 4057 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx", 4058 false, NULL); 4059 Output_section* osymtab_xindex = 4060 this->make_output_section(symtab_xindex_name, 4061 elfcpp::SHT_SYMTAB_SHNDX, 0, 4062 ORDER_INVALID, false); 4063 4064 size_t symcount = off / symsize; 4065 this->symtab_xindex_ = new Output_symtab_xindex(symcount); 4066 4067 osymtab_xindex->add_output_section_data(this->symtab_xindex_); 4068 4069 osymtab_xindex->set_link_section(osymtab); 4070 osymtab_xindex->set_addralign(4); 4071 osymtab_xindex->set_entsize(4); 4072 4073 osymtab_xindex->set_after_input_sections(); 4074 4075 // This tells the driver code to wait until the symbol table 4076 // has written out before writing out the postprocessing 4077 // sections, including the .symtab_shndx section. 4078 this->any_postprocessing_sections_ = true; 4079 } 4080 4081 const char* strtab_name = this->namepool_.add(".strtab", false, NULL); 4082 Output_section* ostrtab = this->make_output_section(strtab_name, 4083 elfcpp::SHT_STRTAB, 4084 0, ORDER_INVALID, 4085 false); 4086 4087 Output_section_data* pstr = new Output_data_strtab(&this->sympool_); 4088 ostrtab->add_output_section_data(pstr); 4089 4090 off_t symtab_off; 4091 if (!parameters->incremental_update()) 4092 symtab_off = align_address(*poff, align); 4093 else 4094 { 4095 symtab_off = this->allocate(off, align, *poff); 4096 if (off == -1) 4097 gold_fallback(_("out of patch space for symbol table; " 4098 "relink with --incremental-full")); 4099 gold_debug(DEBUG_INCREMENTAL, 4100 "create_symtab_sections: %08lx %08lx .symtab", 4101 static_cast<long>(symtab_off), 4102 static_cast<long>(off)); 4103 } 4104 4105 symtab->set_file_offset(symtab_off + global_off); 4106 osymtab->set_file_offset(symtab_off); 4107 osymtab->finalize_data_size(); 4108 osymtab->set_link_section(ostrtab); 4109 osymtab->set_info(local_symcount); 4110 osymtab->set_entsize(symsize); 4111 4112 if (symtab_off + off > *poff) 4113 *poff = symtab_off + off; 4114 } 4115 } 4116 4117 // Create the .shstrtab section, which holds the names of the 4118 // sections. At the time this is called, we have created all the 4119 // output sections except .shstrtab itself. 4120 4121 Output_section* 4122 Layout::create_shstrtab() 4123 { 4124 // FIXME: We don't need to create a .shstrtab section if we are 4125 // stripping everything. 4126 4127 const char* name = this->namepool_.add(".shstrtab", false, NULL); 4128 4129 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0, 4130 ORDER_INVALID, false); 4131 4132 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0) 4133 { 4134 // We can't write out this section until we've set all the 4135 // section names, and we don't set the names of compressed 4136 // output sections until relocations are complete. FIXME: With 4137 // the current names we use, this is unnecessary. 4138 os->set_after_input_sections(); 4139 } 4140 4141 Output_section_data* posd = new Output_data_strtab(&this->namepool_); 4142 os->add_output_section_data(posd); 4143 4144 return os; 4145 } 4146 4147 // Create the section headers. SIZE is 32 or 64. OFF is the file 4148 // offset. 4149 4150 void 4151 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff) 4152 { 4153 Output_section_headers* oshdrs; 4154 oshdrs = new Output_section_headers(this, 4155 &this->segment_list_, 4156 &this->section_list_, 4157 &this->unattached_section_list_, 4158 &this->namepool_, 4159 shstrtab_section); 4160 off_t off; 4161 if (!parameters->incremental_update()) 4162 off = align_address(*poff, oshdrs->addralign()); 4163 else 4164 { 4165 oshdrs->pre_finalize_data_size(); 4166 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff); 4167 if (off == -1) 4168 gold_fallback(_("out of patch space for section header table; " 4169 "relink with --incremental-full")); 4170 gold_debug(DEBUG_INCREMENTAL, 4171 "create_shdrs: %08lx %08lx (section header table)", 4172 static_cast<long>(off), 4173 static_cast<long>(off + oshdrs->data_size())); 4174 } 4175 oshdrs->set_address_and_file_offset(0, off); 4176 off += oshdrs->data_size(); 4177 if (off > *poff) 4178 *poff = off; 4179 this->section_headers_ = oshdrs; 4180 } 4181 4182 // Count the allocated sections. 4183 4184 size_t 4185 Layout::allocated_output_section_count() const 4186 { 4187 size_t section_count = 0; 4188 for (Segment_list::const_iterator p = this->segment_list_.begin(); 4189 p != this->segment_list_.end(); 4190 ++p) 4191 section_count += (*p)->output_section_count(); 4192 return section_count; 4193 } 4194 4195 // Create the dynamic symbol table. 4196 4197 void 4198 Layout::create_dynamic_symtab(const Input_objects* input_objects, 4199 Symbol_table* symtab, 4200 Output_section** pdynstr, 4201 unsigned int* plocal_dynamic_count, 4202 std::vector<Symbol*>* pdynamic_symbols, 4203 Versions* pversions) 4204 { 4205 // Count all the symbols in the dynamic symbol table, and set the 4206 // dynamic symbol indexes. 4207 4208 // Skip symbol 0, which is always all zeroes. 4209 unsigned int index = 1; 4210 4211 // Add STT_SECTION symbols for each Output section which needs one. 4212 for (Section_list::iterator p = this->section_list_.begin(); 4213 p != this->section_list_.end(); 4214 ++p) 4215 { 4216 if (!(*p)->needs_dynsym_index()) 4217 (*p)->set_dynsym_index(-1U); 4218 else 4219 { 4220 (*p)->set_dynsym_index(index); 4221 ++index; 4222 } 4223 } 4224 4225 // Count the local symbols that need to go in the dynamic symbol table, 4226 // and set the dynamic symbol indexes. 4227 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); 4228 p != input_objects->relobj_end(); 4229 ++p) 4230 { 4231 unsigned int new_index = (*p)->set_local_dynsym_indexes(index); 4232 index = new_index; 4233 } 4234 4235 unsigned int local_symcount = index; 4236 *plocal_dynamic_count = local_symcount; 4237 4238 index = symtab->set_dynsym_indexes(index, pdynamic_symbols, 4239 &this->dynpool_, pversions); 4240 4241 int symsize; 4242 unsigned int align; 4243 const int size = parameters->target().get_size(); 4244 if (size == 32) 4245 { 4246 symsize = elfcpp::Elf_sizes<32>::sym_size; 4247 align = 4; 4248 } 4249 else if (size == 64) 4250 { 4251 symsize = elfcpp::Elf_sizes<64>::sym_size; 4252 align = 8; 4253 } 4254 else 4255 gold_unreachable(); 4256 4257 // Create the dynamic symbol table section. 4258 4259 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym", 4260 elfcpp::SHT_DYNSYM, 4261 elfcpp::SHF_ALLOC, 4262 false, 4263 ORDER_DYNAMIC_LINKER, 4264 false); 4265 4266 // Check for NULL as a linker script may discard .dynsym. 4267 if (dynsym != NULL) 4268 { 4269 Output_section_data* odata = new Output_data_fixed_space(index * symsize, 4270 align, 4271 "** dynsym"); 4272 dynsym->add_output_section_data(odata); 4273 4274 dynsym->set_info(local_symcount); 4275 dynsym->set_entsize(symsize); 4276 dynsym->set_addralign(align); 4277 4278 this->dynsym_section_ = dynsym; 4279 } 4280 4281 Output_data_dynamic* const odyn = this->dynamic_data_; 4282 if (odyn != NULL) 4283 { 4284 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym); 4285 odyn->add_constant(elfcpp::DT_SYMENT, symsize); 4286 } 4287 4288 // If there are more than SHN_LORESERVE allocated sections, we 4289 // create a .dynsym_shndx section. It is possible that we don't 4290 // need one, because it is possible that there are no dynamic 4291 // symbols in any of the sections with indexes larger than 4292 // SHN_LORESERVE. This is probably unusual, though, and at this 4293 // time we don't know the actual section indexes so it is 4294 // inconvenient to check. 4295 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE) 4296 { 4297 Output_section* dynsym_xindex = 4298 this->choose_output_section(NULL, ".dynsym_shndx", 4299 elfcpp::SHT_SYMTAB_SHNDX, 4300 elfcpp::SHF_ALLOC, 4301 false, ORDER_DYNAMIC_LINKER, false); 4302 4303 if (dynsym_xindex != NULL) 4304 { 4305 this->dynsym_xindex_ = new Output_symtab_xindex(index); 4306 4307 dynsym_xindex->add_output_section_data(this->dynsym_xindex_); 4308 4309 dynsym_xindex->set_link_section(dynsym); 4310 dynsym_xindex->set_addralign(4); 4311 dynsym_xindex->set_entsize(4); 4312 4313 dynsym_xindex->set_after_input_sections(); 4314 4315 // This tells the driver code to wait until the symbol table 4316 // has written out before writing out the postprocessing 4317 // sections, including the .dynsym_shndx section. 4318 this->any_postprocessing_sections_ = true; 4319 } 4320 } 4321 4322 // Create the dynamic string table section. 4323 4324 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr", 4325 elfcpp::SHT_STRTAB, 4326 elfcpp::SHF_ALLOC, 4327 false, 4328 ORDER_DYNAMIC_LINKER, 4329 false); 4330 *pdynstr = dynstr; 4331 if (dynstr != NULL) 4332 { 4333 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_); 4334 dynstr->add_output_section_data(strdata); 4335 4336 if (dynsym != NULL) 4337 dynsym->set_link_section(dynstr); 4338 if (this->dynamic_section_ != NULL) 4339 this->dynamic_section_->set_link_section(dynstr); 4340 4341 if (odyn != NULL) 4342 { 4343 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr); 4344 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr); 4345 } 4346 } 4347 4348 // Create the hash tables. The Gnu-style hash table must be 4349 // built first, because it changes the order of the symbols 4350 // in the dynamic symbol table. 4351 4352 if (strcmp(parameters->options().hash_style(), "gnu") == 0 4353 || strcmp(parameters->options().hash_style(), "both") == 0) 4354 { 4355 unsigned char* phash; 4356 unsigned int hashlen; 4357 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount, 4358 &phash, &hashlen); 4359 4360 Output_section* hashsec = 4361 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH, 4362 elfcpp::SHF_ALLOC, false, 4363 ORDER_DYNAMIC_LINKER, false); 4364 4365 Output_section_data* hashdata = new Output_data_const_buffer(phash, 4366 hashlen, 4367 align, 4368 "** hash"); 4369 if (hashsec != NULL && hashdata != NULL) 4370 hashsec->add_output_section_data(hashdata); 4371 4372 if (hashsec != NULL) 4373 { 4374 if (dynsym != NULL) 4375 hashsec->set_link_section(dynsym); 4376 4377 // For a 64-bit target, the entries in .gnu.hash do not have 4378 // a uniform size, so we only set the entry size for a 4379 // 32-bit target. 4380 if (parameters->target().get_size() == 32) 4381 hashsec->set_entsize(4); 4382 4383 if (odyn != NULL) 4384 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec); 4385 } 4386 } 4387 4388 if (strcmp(parameters->options().hash_style(), "sysv") == 0 4389 || strcmp(parameters->options().hash_style(), "both") == 0) 4390 { 4391 unsigned char* phash; 4392 unsigned int hashlen; 4393 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount, 4394 &phash, &hashlen); 4395 4396 Output_section* hashsec = 4397 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH, 4398 elfcpp::SHF_ALLOC, false, 4399 ORDER_DYNAMIC_LINKER, false); 4400 4401 Output_section_data* hashdata = new Output_data_const_buffer(phash, 4402 hashlen, 4403 align, 4404 "** hash"); 4405 if (hashsec != NULL && hashdata != NULL) 4406 hashsec->add_output_section_data(hashdata); 4407 4408 if (hashsec != NULL) 4409 { 4410 if (dynsym != NULL) 4411 hashsec->set_link_section(dynsym); 4412 hashsec->set_entsize(parameters->target().hash_entry_size() / 8); 4413 } 4414 4415 if (odyn != NULL) 4416 odyn->add_section_address(elfcpp::DT_HASH, hashsec); 4417 } 4418 } 4419 4420 // Assign offsets to each local portion of the dynamic symbol table. 4421 4422 void 4423 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects) 4424 { 4425 Output_section* dynsym = this->dynsym_section_; 4426 if (dynsym == NULL) 4427 return; 4428 4429 off_t off = dynsym->offset(); 4430 4431 // Skip the dummy symbol at the start of the section. 4432 off += dynsym->entsize(); 4433 4434 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); 4435 p != input_objects->relobj_end(); 4436 ++p) 4437 { 4438 unsigned int count = (*p)->set_local_dynsym_offset(off); 4439 off += count * dynsym->entsize(); 4440 } 4441 } 4442 4443 // Create the version sections. 4444 4445 void 4446 Layout::create_version_sections(const Versions* versions, 4447 const Symbol_table* symtab, 4448 unsigned int local_symcount, 4449 const std::vector<Symbol*>& dynamic_symbols, 4450 const Output_section* dynstr) 4451 { 4452 if (!versions->any_defs() && !versions->any_needs()) 4453 return; 4454 4455 switch (parameters->size_and_endianness()) 4456 { 4457 #ifdef HAVE_TARGET_32_LITTLE 4458 case Parameters::TARGET_32_LITTLE: 4459 this->sized_create_version_sections<32, false>(versions, symtab, 4460 local_symcount, 4461 dynamic_symbols, dynstr); 4462 break; 4463 #endif 4464 #ifdef HAVE_TARGET_32_BIG 4465 case Parameters::TARGET_32_BIG: 4466 this->sized_create_version_sections<32, true>(versions, symtab, 4467 local_symcount, 4468 dynamic_symbols, dynstr); 4469 break; 4470 #endif 4471 #ifdef HAVE_TARGET_64_LITTLE 4472 case Parameters::TARGET_64_LITTLE: 4473 this->sized_create_version_sections<64, false>(versions, symtab, 4474 local_symcount, 4475 dynamic_symbols, dynstr); 4476 break; 4477 #endif 4478 #ifdef HAVE_TARGET_64_BIG 4479 case Parameters::TARGET_64_BIG: 4480 this->sized_create_version_sections<64, true>(versions, symtab, 4481 local_symcount, 4482 dynamic_symbols, dynstr); 4483 break; 4484 #endif 4485 default: 4486 gold_unreachable(); 4487 } 4488 } 4489 4490 // Create the version sections, sized version. 4491 4492 template<int size, bool big_endian> 4493 void 4494 Layout::sized_create_version_sections( 4495 const Versions* versions, 4496 const Symbol_table* symtab, 4497 unsigned int local_symcount, 4498 const std::vector<Symbol*>& dynamic_symbols, 4499 const Output_section* dynstr) 4500 { 4501 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version", 4502 elfcpp::SHT_GNU_versym, 4503 elfcpp::SHF_ALLOC, 4504 false, 4505 ORDER_DYNAMIC_LINKER, 4506 false); 4507 4508 // Check for NULL since a linker script may discard this section. 4509 if (vsec != NULL) 4510 { 4511 unsigned char* vbuf; 4512 unsigned int vsize; 4513 versions->symbol_section_contents<size, big_endian>(symtab, 4514 &this->dynpool_, 4515 local_symcount, 4516 dynamic_symbols, 4517 &vbuf, &vsize); 4518 4519 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2, 4520 "** versions"); 4521 4522 vsec->add_output_section_data(vdata); 4523 vsec->set_entsize(2); 4524 vsec->set_link_section(this->dynsym_section_); 4525 } 4526 4527 Output_data_dynamic* const odyn = this->dynamic_data_; 4528 if (odyn != NULL && vsec != NULL) 4529 odyn->add_section_address(elfcpp::DT_VERSYM, vsec); 4530 4531 if (versions->any_defs()) 4532 { 4533 Output_section* vdsec; 4534 vdsec = this->choose_output_section(NULL, ".gnu.version_d", 4535 elfcpp::SHT_GNU_verdef, 4536 elfcpp::SHF_ALLOC, 4537 false, ORDER_DYNAMIC_LINKER, false); 4538 4539 if (vdsec != NULL) 4540 { 4541 unsigned char* vdbuf; 4542 unsigned int vdsize; 4543 unsigned int vdentries; 4544 versions->def_section_contents<size, big_endian>(&this->dynpool_, 4545 &vdbuf, &vdsize, 4546 &vdentries); 4547 4548 Output_section_data* vddata = 4549 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs"); 4550 4551 vdsec->add_output_section_data(vddata); 4552 vdsec->set_link_section(dynstr); 4553 vdsec->set_info(vdentries); 4554 4555 if (odyn != NULL) 4556 { 4557 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec); 4558 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries); 4559 } 4560 } 4561 } 4562 4563 if (versions->any_needs()) 4564 { 4565 Output_section* vnsec; 4566 vnsec = this->choose_output_section(NULL, ".gnu.version_r", 4567 elfcpp::SHT_GNU_verneed, 4568 elfcpp::SHF_ALLOC, 4569 false, ORDER_DYNAMIC_LINKER, false); 4570 4571 if (vnsec != NULL) 4572 { 4573 unsigned char* vnbuf; 4574 unsigned int vnsize; 4575 unsigned int vnentries; 4576 versions->need_section_contents<size, big_endian>(&this->dynpool_, 4577 &vnbuf, &vnsize, 4578 &vnentries); 4579 4580 Output_section_data* vndata = 4581 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs"); 4582 4583 vnsec->add_output_section_data(vndata); 4584 vnsec->set_link_section(dynstr); 4585 vnsec->set_info(vnentries); 4586 4587 if (odyn != NULL) 4588 { 4589 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec); 4590 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries); 4591 } 4592 } 4593 } 4594 } 4595 4596 // Create the .interp section and PT_INTERP segment. 4597 4598 void 4599 Layout::create_interp(const Target* target) 4600 { 4601 gold_assert(this->interp_segment_ == NULL); 4602 4603 const char* interp = parameters->options().dynamic_linker(); 4604 if (interp == NULL) 4605 { 4606 interp = target->dynamic_linker(); 4607 gold_assert(interp != NULL); 4608 } 4609 4610 size_t len = strlen(interp) + 1; 4611 4612 Output_section_data* odata = new Output_data_const(interp, len, 1); 4613 4614 Output_section* osec = this->choose_output_section(NULL, ".interp", 4615 elfcpp::SHT_PROGBITS, 4616 elfcpp::SHF_ALLOC, 4617 false, ORDER_INTERP, 4618 false); 4619 if (osec != NULL) 4620 osec->add_output_section_data(odata); 4621 } 4622 4623 // Add dynamic tags for the PLT and the dynamic relocs. This is 4624 // called by the target-specific code. This does nothing if not doing 4625 // a dynamic link. 4626 4627 // USE_REL is true for REL relocs rather than RELA relocs. 4628 4629 // If PLT_GOT is not NULL, then DT_PLTGOT points to it. 4630 4631 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL, 4632 // and we also set DT_PLTREL. We use PLT_REL's output section, since 4633 // some targets have multiple reloc sections in PLT_REL. 4634 4635 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA, 4636 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output 4637 // section. 4638 4639 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an 4640 // executable. 4641 4642 void 4643 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, 4644 const Output_data* plt_rel, 4645 const Output_data_reloc_generic* dyn_rel, 4646 bool add_debug, bool dynrel_includes_plt) 4647 { 4648 Output_data_dynamic* odyn = this->dynamic_data_; 4649 if (odyn == NULL) 4650 return; 4651 4652 if (plt_got != NULL && plt_got->output_section() != NULL) 4653 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got); 4654 4655 if (plt_rel != NULL && plt_rel->output_section() != NULL) 4656 { 4657 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section()); 4658 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section()); 4659 odyn->add_constant(elfcpp::DT_PLTREL, 4660 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA); 4661 } 4662 4663 if ((dyn_rel != NULL && dyn_rel->output_section() != NULL) 4664 || (dynrel_includes_plt 4665 && plt_rel != NULL 4666 && plt_rel->output_section() != NULL)) 4667 { 4668 bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL; 4669 bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL; 4670 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA, 4671 (have_dyn_rel 4672 ? dyn_rel->output_section() 4673 : plt_rel->output_section())); 4674 elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ; 4675 if (have_dyn_rel && have_plt_rel && dynrel_includes_plt) 4676 odyn->add_section_size(size_tag, 4677 dyn_rel->output_section(), 4678 plt_rel->output_section()); 4679 else if (have_dyn_rel) 4680 odyn->add_section_size(size_tag, dyn_rel->output_section()); 4681 else 4682 odyn->add_section_size(size_tag, plt_rel->output_section()); 4683 const int size = parameters->target().get_size(); 4684 elfcpp::DT rel_tag; 4685 int rel_size; 4686 if (use_rel) 4687 { 4688 rel_tag = elfcpp::DT_RELENT; 4689 if (size == 32) 4690 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size; 4691 else if (size == 64) 4692 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size; 4693 else 4694 gold_unreachable(); 4695 } 4696 else 4697 { 4698 rel_tag = elfcpp::DT_RELAENT; 4699 if (size == 32) 4700 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size; 4701 else if (size == 64) 4702 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size; 4703 else 4704 gold_unreachable(); 4705 } 4706 odyn->add_constant(rel_tag, rel_size); 4707 4708 if (parameters->options().combreloc() && have_dyn_rel) 4709 { 4710 size_t c = dyn_rel->relative_reloc_count(); 4711 if (c > 0) 4712 odyn->add_constant((use_rel 4713 ? elfcpp::DT_RELCOUNT 4714 : elfcpp::DT_RELACOUNT), 4715 c); 4716 } 4717 } 4718 4719 if (add_debug && !parameters->options().shared()) 4720 { 4721 // The value of the DT_DEBUG tag is filled in by the dynamic 4722 // linker at run time, and used by the debugger. 4723 odyn->add_constant(elfcpp::DT_DEBUG, 0); 4724 } 4725 } 4726 4727 void 4728 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val) 4729 { 4730 Output_data_dynamic* odyn = this->dynamic_data_; 4731 if (odyn == NULL) 4732 return; 4733 odyn->add_constant(tag, val); 4734 } 4735 4736 // Finish the .dynamic section and PT_DYNAMIC segment. 4737 4738 void 4739 Layout::finish_dynamic_section(const Input_objects* input_objects, 4740 const Symbol_table* symtab) 4741 { 4742 if (!this->script_options_->saw_phdrs_clause() 4743 && this->dynamic_section_ != NULL) 4744 { 4745 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC, 4746 (elfcpp::PF_R 4747 | elfcpp::PF_W)); 4748 oseg->add_output_section_to_nonload(this->dynamic_section_, 4749 elfcpp::PF_R | elfcpp::PF_W); 4750 } 4751 4752 Output_data_dynamic* const odyn = this->dynamic_data_; 4753 if (odyn == NULL) 4754 return; 4755 4756 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin(); 4757 p != input_objects->dynobj_end(); 4758 ++p) 4759 { 4760 if (!(*p)->is_needed() && (*p)->as_needed()) 4761 { 4762 // This dynamic object was linked with --as-needed, but it 4763 // is not needed. 4764 continue; 4765 } 4766 4767 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname()); 4768 } 4769 4770 if (parameters->options().shared()) 4771 { 4772 const char* soname = parameters->options().soname(); 4773 if (soname != NULL) 4774 odyn->add_string(elfcpp::DT_SONAME, soname); 4775 } 4776 4777 Symbol* sym = symtab->lookup(parameters->options().init()); 4778 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) 4779 odyn->add_symbol(elfcpp::DT_INIT, sym); 4780 4781 sym = symtab->lookup(parameters->options().fini()); 4782 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) 4783 odyn->add_symbol(elfcpp::DT_FINI, sym); 4784 4785 // Look for .init_array, .preinit_array and .fini_array by checking 4786 // section types. 4787 for(Layout::Section_list::const_iterator p = this->section_list_.begin(); 4788 p != this->section_list_.end(); 4789 ++p) 4790 switch((*p)->type()) 4791 { 4792 case elfcpp::SHT_FINI_ARRAY: 4793 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p); 4794 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); 4795 break; 4796 case elfcpp::SHT_INIT_ARRAY: 4797 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p); 4798 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); 4799 break; 4800 case elfcpp::SHT_PREINIT_ARRAY: 4801 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p); 4802 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); 4803 break; 4804 default: 4805 break; 4806 } 4807 4808 // Add a DT_RPATH entry if needed. 4809 const General_options::Dir_list& rpath(parameters->options().rpath()); 4810 if (!rpath.empty()) 4811 { 4812 std::string rpath_val; 4813 for (General_options::Dir_list::const_iterator p = rpath.begin(); 4814 p != rpath.end(); 4815 ++p) 4816 { 4817 if (rpath_val.empty()) 4818 rpath_val = p->name(); 4819 else 4820 { 4821 // Eliminate duplicates. 4822 General_options::Dir_list::const_iterator q; 4823 for (q = rpath.begin(); q != p; ++q) 4824 if (q->name() == p->name()) 4825 break; 4826 if (q == p) 4827 { 4828 rpath_val += ':'; 4829 rpath_val += p->name(); 4830 } 4831 } 4832 } 4833 4834 if (!parameters->options().enable_new_dtags()) 4835 odyn->add_string(elfcpp::DT_RPATH, rpath_val); 4836 else 4837 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val); 4838 } 4839 4840 // Look for text segments that have dynamic relocations. 4841 bool have_textrel = false; 4842 if (!this->script_options_->saw_sections_clause()) 4843 { 4844 for (Segment_list::const_iterator p = this->segment_list_.begin(); 4845 p != this->segment_list_.end(); 4846 ++p) 4847 { 4848 if ((*p)->type() == elfcpp::PT_LOAD 4849 && ((*p)->flags() & elfcpp::PF_W) == 0 4850 && (*p)->has_dynamic_reloc()) 4851 { 4852 have_textrel = true; 4853 break; 4854 } 4855 } 4856 } 4857 else 4858 { 4859 // We don't know the section -> segment mapping, so we are 4860 // conservative and just look for readonly sections with 4861 // relocations. If those sections wind up in writable segments, 4862 // then we have created an unnecessary DT_TEXTREL entry. 4863 for (Section_list::const_iterator p = this->section_list_.begin(); 4864 p != this->section_list_.end(); 4865 ++p) 4866 { 4867 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0 4868 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0 4869 && (*p)->has_dynamic_reloc()) 4870 { 4871 have_textrel = true; 4872 break; 4873 } 4874 } 4875 } 4876 4877 if (parameters->options().filter() != NULL) 4878 odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter()); 4879 if (parameters->options().any_auxiliary()) 4880 { 4881 for (options::String_set::const_iterator p = 4882 parameters->options().auxiliary_begin(); 4883 p != parameters->options().auxiliary_end(); 4884 ++p) 4885 odyn->add_string(elfcpp::DT_AUXILIARY, *p); 4886 } 4887 4888 // Add a DT_FLAGS entry if necessary. 4889 unsigned int flags = 0; 4890 if (have_textrel) 4891 { 4892 // Add a DT_TEXTREL for compatibility with older loaders. 4893 odyn->add_constant(elfcpp::DT_TEXTREL, 0); 4894 flags |= elfcpp::DF_TEXTREL; 4895 4896 if (parameters->options().text()) 4897 gold_error(_("read-only segment has dynamic relocations")); 4898 else if (parameters->options().warn_shared_textrel() 4899 && parameters->options().shared()) 4900 gold_warning(_("shared library text segment is not shareable")); 4901 } 4902 if (parameters->options().shared() && this->has_static_tls()) 4903 flags |= elfcpp::DF_STATIC_TLS; 4904 if (parameters->options().origin()) 4905 flags |= elfcpp::DF_ORIGIN; 4906 if (parameters->options().Bsymbolic() 4907 && !parameters->options().have_dynamic_list()) 4908 { 4909 flags |= elfcpp::DF_SYMBOLIC; 4910 // Add DT_SYMBOLIC for compatibility with older loaders. 4911 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0); 4912 } 4913 if (parameters->options().now()) 4914 flags |= elfcpp::DF_BIND_NOW; 4915 if (flags != 0) 4916 odyn->add_constant(elfcpp::DT_FLAGS, flags); 4917 4918 flags = 0; 4919 if (parameters->options().global()) 4920 flags |= elfcpp::DF_1_GLOBAL; 4921 if (parameters->options().initfirst()) 4922 flags |= elfcpp::DF_1_INITFIRST; 4923 if (parameters->options().interpose()) 4924 flags |= elfcpp::DF_1_INTERPOSE; 4925 if (parameters->options().loadfltr()) 4926 flags |= elfcpp::DF_1_LOADFLTR; 4927 if (parameters->options().nodefaultlib()) 4928 flags |= elfcpp::DF_1_NODEFLIB; 4929 if (parameters->options().nodelete()) 4930 flags |= elfcpp::DF_1_NODELETE; 4931 if (parameters->options().nodlopen()) 4932 flags |= elfcpp::DF_1_NOOPEN; 4933 if (parameters->options().nodump()) 4934 flags |= elfcpp::DF_1_NODUMP; 4935 if (!parameters->options().shared()) 4936 flags &= ~(elfcpp::DF_1_INITFIRST 4937 | elfcpp::DF_1_NODELETE 4938 | elfcpp::DF_1_NOOPEN); 4939 if (parameters->options().origin()) 4940 flags |= elfcpp::DF_1_ORIGIN; 4941 if (parameters->options().now()) 4942 flags |= elfcpp::DF_1_NOW; 4943 if (parameters->options().Bgroup()) 4944 flags |= elfcpp::DF_1_GROUP; 4945 if (flags != 0) 4946 odyn->add_constant(elfcpp::DT_FLAGS_1, flags); 4947 } 4948 4949 // Set the size of the _DYNAMIC symbol table to be the size of the 4950 // dynamic data. 4951 4952 void 4953 Layout::set_dynamic_symbol_size(const Symbol_table* symtab) 4954 { 4955 Output_data_dynamic* const odyn = this->dynamic_data_; 4956 if (odyn == NULL) 4957 return; 4958 odyn->finalize_data_size(); 4959 if (this->dynamic_symbol_ == NULL) 4960 return; 4961 off_t data_size = odyn->data_size(); 4962 const int size = parameters->target().get_size(); 4963 if (size == 32) 4964 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size); 4965 else if (size == 64) 4966 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size); 4967 else 4968 gold_unreachable(); 4969 } 4970 4971 // The mapping of input section name prefixes to output section names. 4972 // In some cases one prefix is itself a prefix of another prefix; in 4973 // such a case the longer prefix must come first. These prefixes are 4974 // based on the GNU linker default ELF linker script. 4975 4976 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 } 4977 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 } 4978 const Layout::Section_name_mapping Layout::section_name_mapping[] = 4979 { 4980 MAPPING_INIT(".text.", ".text"), 4981 MAPPING_INIT(".rodata.", ".rodata"), 4982 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"), 4983 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"), 4984 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"), 4985 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"), 4986 MAPPING_INIT(".data.", ".data"), 4987 MAPPING_INIT(".bss.", ".bss"), 4988 MAPPING_INIT(".tdata.", ".tdata"), 4989 MAPPING_INIT(".tbss.", ".tbss"), 4990 MAPPING_INIT(".init_array.", ".init_array"), 4991 MAPPING_INIT(".fini_array.", ".fini_array"), 4992 MAPPING_INIT(".sdata.", ".sdata"), 4993 MAPPING_INIT(".sbss.", ".sbss"), 4994 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled 4995 // differently depending on whether it is creating a shared library. 4996 MAPPING_INIT(".sdata2.", ".sdata"), 4997 MAPPING_INIT(".sbss2.", ".sbss"), 4998 MAPPING_INIT(".lrodata.", ".lrodata"), 4999 MAPPING_INIT(".ldata.", ".ldata"), 5000 MAPPING_INIT(".lbss.", ".lbss"), 5001 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"), 5002 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"), 5003 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"), 5004 MAPPING_INIT(".gnu.linkonce.t.", ".text"), 5005 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"), 5006 MAPPING_INIT(".gnu.linkonce.d.", ".data"), 5007 MAPPING_INIT(".gnu.linkonce.b.", ".bss"), 5008 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"), 5009 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"), 5010 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"), 5011 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"), 5012 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"), 5013 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"), 5014 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"), 5015 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"), 5016 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"), 5017 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"), 5018 MAPPING_INIT(".ARM.extab", ".ARM.extab"), 5019 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"), 5020 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"), 5021 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"), 5022 }; 5023 #undef MAPPING_INIT 5024 #undef MAPPING_INIT_EXACT 5025 5026 const int Layout::section_name_mapping_count = 5027 (sizeof(Layout::section_name_mapping) 5028 / sizeof(Layout::section_name_mapping[0])); 5029 5030 // Choose the output section name to use given an input section name. 5031 // Set *PLEN to the length of the name. *PLEN is initialized to the 5032 // length of NAME. 5033 5034 const char* 5035 Layout::output_section_name(const Relobj* relobj, const char* name, 5036 size_t* plen) 5037 { 5038 // gcc 4.3 generates the following sorts of section names when it 5039 // needs a section name specific to a function: 5040 // .text.FN 5041 // .rodata.FN 5042 // .sdata2.FN 5043 // .data.FN 5044 // .data.rel.FN 5045 // .data.rel.local.FN 5046 // .data.rel.ro.FN 5047 // .data.rel.ro.local.FN 5048 // .sdata.FN 5049 // .bss.FN 5050 // .sbss.FN 5051 // .tdata.FN 5052 // .tbss.FN 5053 5054 // The GNU linker maps all of those to the part before the .FN, 5055 // except that .data.rel.local.FN is mapped to .data, and 5056 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections 5057 // beginning with .data.rel.ro.local are grouped together. 5058 5059 // For an anonymous namespace, the string FN can contain a '.'. 5060 5061 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the 5062 // GNU linker maps to .rodata. 5063 5064 // The .data.rel.ro sections are used with -z relro. The sections 5065 // are recognized by name. We use the same names that the GNU 5066 // linker does for these sections. 5067 5068 // It is hard to handle this in a principled way, so we don't even 5069 // try. We use a table of mappings. If the input section name is 5070 // not found in the table, we simply use it as the output section 5071 // name. 5072 5073 const Section_name_mapping* psnm = section_name_mapping; 5074 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm) 5075 { 5076 if (psnm->fromlen > 0) 5077 { 5078 if (strncmp(name, psnm->from, psnm->fromlen) == 0) 5079 { 5080 *plen = psnm->tolen; 5081 return psnm->to; 5082 } 5083 } 5084 else 5085 { 5086 if (strcmp(name, psnm->from) == 0) 5087 { 5088 *plen = psnm->tolen; 5089 return psnm->to; 5090 } 5091 } 5092 } 5093 5094 // As an additional complication, .ctors sections are output in 5095 // either .ctors or .init_array sections, and .dtors sections are 5096 // output in either .dtors or .fini_array sections. 5097 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name)) 5098 { 5099 if (parameters->options().ctors_in_init_array()) 5100 { 5101 *plen = 11; 5102 return name[1] == 'c' ? ".init_array" : ".fini_array"; 5103 } 5104 else 5105 { 5106 *plen = 6; 5107 return name[1] == 'c' ? ".ctors" : ".dtors"; 5108 } 5109 } 5110 if (parameters->options().ctors_in_init_array() 5111 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0)) 5112 { 5113 // To make .init_array/.fini_array work with gcc we must exclude 5114 // .ctors and .dtors sections from the crtbegin and crtend 5115 // files. 5116 if (relobj == NULL 5117 || (!Layout::match_file_name(relobj, "crtbegin") 5118 && !Layout::match_file_name(relobj, "crtend"))) 5119 { 5120 *plen = 11; 5121 return name[1] == 'c' ? ".init_array" : ".fini_array"; 5122 } 5123 } 5124 5125 return name; 5126 } 5127 5128 // Return true if RELOBJ is an input file whose base name matches 5129 // FILE_NAME. The base name must have an extension of ".o", and must 5130 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is 5131 // to match crtbegin.o as well as crtbeginS.o without getting confused 5132 // by other possibilities. Overall matching the file name this way is 5133 // a dreadful hack, but the GNU linker does it in order to better 5134 // support gcc, and we need to be compatible. 5135 5136 bool 5137 Layout::match_file_name(const Relobj* relobj, const char* match) 5138 { 5139 const std::string& file_name(relobj->name()); 5140 const char* base_name = lbasename(file_name.c_str()); 5141 size_t match_len = strlen(match); 5142 if (strncmp(base_name, match, match_len) != 0) 5143 return false; 5144 size_t base_len = strlen(base_name); 5145 if (base_len != match_len + 2 && base_len != match_len + 3) 5146 return false; 5147 return memcmp(base_name + base_len - 2, ".o", 2) == 0; 5148 } 5149 5150 // Check if a comdat group or .gnu.linkonce section with the given 5151 // NAME is selected for the link. If there is already a section, 5152 // *KEPT_SECTION is set to point to the existing section and the 5153 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and 5154 // IS_GROUP_NAME are recorded for this NAME in the layout object, 5155 // *KEPT_SECTION is set to the internal copy and the function returns 5156 // true. 5157 5158 bool 5159 Layout::find_or_add_kept_section(const std::string& name, 5160 Relobj* object, 5161 unsigned int shndx, 5162 bool is_comdat, 5163 bool is_group_name, 5164 Kept_section** kept_section) 5165 { 5166 // It's normal to see a couple of entries here, for the x86 thunk 5167 // sections. If we see more than a few, we're linking a C++ 5168 // program, and we resize to get more space to minimize rehashing. 5169 if (this->signatures_.size() > 4 5170 && !this->resized_signatures_) 5171 { 5172 reserve_unordered_map(&this->signatures_, 5173 this->number_of_input_files_ * 64); 5174 this->resized_signatures_ = true; 5175 } 5176 5177 Kept_section candidate; 5178 std::pair<Signatures::iterator, bool> ins = 5179 this->signatures_.insert(std::make_pair(name, candidate)); 5180 5181 if (kept_section != NULL) 5182 *kept_section = &ins.first->second; 5183 if (ins.second) 5184 { 5185 // This is the first time we've seen this signature. 5186 ins.first->second.set_object(object); 5187 ins.first->second.set_shndx(shndx); 5188 if (is_comdat) 5189 ins.first->second.set_is_comdat(); 5190 if (is_group_name) 5191 ins.first->second.set_is_group_name(); 5192 return true; 5193 } 5194 5195 // We have already seen this signature. 5196 5197 if (ins.first->second.is_group_name()) 5198 { 5199 // We've already seen a real section group with this signature. 5200 // If the kept group is from a plugin object, and we're in the 5201 // replacement phase, accept the new one as a replacement. 5202 if (ins.first->second.object() == NULL 5203 && parameters->options().plugins()->in_replacement_phase()) 5204 { 5205 ins.first->second.set_object(object); 5206 ins.first->second.set_shndx(shndx); 5207 return true; 5208 } 5209 return false; 5210 } 5211 else if (is_group_name) 5212 { 5213 // This is a real section group, and we've already seen a 5214 // linkonce section with this signature. Record that we've seen 5215 // a section group, and don't include this section group. 5216 ins.first->second.set_is_group_name(); 5217 return false; 5218 } 5219 else 5220 { 5221 // We've already seen a linkonce section and this is a linkonce 5222 // section. These don't block each other--this may be the same 5223 // symbol name with different section types. 5224 return true; 5225 } 5226 } 5227 5228 // Store the allocated sections into the section list. 5229 5230 void 5231 Layout::get_allocated_sections(Section_list* section_list) const 5232 { 5233 for (Section_list::const_iterator p = this->section_list_.begin(); 5234 p != this->section_list_.end(); 5235 ++p) 5236 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0) 5237 section_list->push_back(*p); 5238 } 5239 5240 // Store the executable sections into the section list. 5241 5242 void 5243 Layout::get_executable_sections(Section_list* section_list) const 5244 { 5245 for (Section_list::const_iterator p = this->section_list_.begin(); 5246 p != this->section_list_.end(); 5247 ++p) 5248 if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) 5249 == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) 5250 section_list->push_back(*p); 5251 } 5252 5253 // Create an output segment. 5254 5255 Output_segment* 5256 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) 5257 { 5258 gold_assert(!parameters->options().relocatable()); 5259 Output_segment* oseg = new Output_segment(type, flags); 5260 this->segment_list_.push_back(oseg); 5261 5262 if (type == elfcpp::PT_TLS) 5263 this->tls_segment_ = oseg; 5264 else if (type == elfcpp::PT_GNU_RELRO) 5265 this->relro_segment_ = oseg; 5266 else if (type == elfcpp::PT_INTERP) 5267 this->interp_segment_ = oseg; 5268 5269 return oseg; 5270 } 5271 5272 // Return the file offset of the normal symbol table. 5273 5274 off_t 5275 Layout::symtab_section_offset() const 5276 { 5277 if (this->symtab_section_ != NULL) 5278 return this->symtab_section_->offset(); 5279 return 0; 5280 } 5281 5282 // Return the section index of the normal symbol table. It may have 5283 // been stripped by the -s/--strip-all option. 5284 5285 unsigned int 5286 Layout::symtab_section_shndx() const 5287 { 5288 if (this->symtab_section_ != NULL) 5289 return this->symtab_section_->out_shndx(); 5290 return 0; 5291 } 5292 5293 // Write out the Output_sections. Most won't have anything to write, 5294 // since most of the data will come from input sections which are 5295 // handled elsewhere. But some Output_sections do have Output_data. 5296 5297 void 5298 Layout::write_output_sections(Output_file* of) const 5299 { 5300 for (Section_list::const_iterator p = this->section_list_.begin(); 5301 p != this->section_list_.end(); 5302 ++p) 5303 { 5304 if (!(*p)->after_input_sections()) 5305 (*p)->write(of); 5306 } 5307 } 5308 5309 // Write out data not associated with a section or the symbol table. 5310 5311 void 5312 Layout::write_data(const Symbol_table* symtab, Output_file* of) const 5313 { 5314 if (!parameters->options().strip_all()) 5315 { 5316 const Output_section* symtab_section = this->symtab_section_; 5317 for (Section_list::const_iterator p = this->section_list_.begin(); 5318 p != this->section_list_.end(); 5319 ++p) 5320 { 5321 if ((*p)->needs_symtab_index()) 5322 { 5323 gold_assert(symtab_section != NULL); 5324 unsigned int index = (*p)->symtab_index(); 5325 gold_assert(index > 0 && index != -1U); 5326 off_t off = (symtab_section->offset() 5327 + index * symtab_section->entsize()); 5328 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off); 5329 } 5330 } 5331 } 5332 5333 const Output_section* dynsym_section = this->dynsym_section_; 5334 for (Section_list::const_iterator p = this->section_list_.begin(); 5335 p != this->section_list_.end(); 5336 ++p) 5337 { 5338 if ((*p)->needs_dynsym_index()) 5339 { 5340 gold_assert(dynsym_section != NULL); 5341 unsigned int index = (*p)->dynsym_index(); 5342 gold_assert(index > 0 && index != -1U); 5343 off_t off = (dynsym_section->offset() 5344 + index * dynsym_section->entsize()); 5345 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off); 5346 } 5347 } 5348 5349 // Write out the Output_data which are not in an Output_section. 5350 for (Data_list::const_iterator p = this->special_output_list_.begin(); 5351 p != this->special_output_list_.end(); 5352 ++p) 5353 (*p)->write(of); 5354 5355 // Write out the Output_data which are not in an Output_section 5356 // and are regenerated in each iteration of relaxation. 5357 for (Data_list::const_iterator p = this->relax_output_list_.begin(); 5358 p != this->relax_output_list_.end(); 5359 ++p) 5360 (*p)->write(of); 5361 } 5362 5363 // Write out the Output_sections which can only be written after the 5364 // input sections are complete. 5365 5366 void 5367 Layout::write_sections_after_input_sections(Output_file* of) 5368 { 5369 // Determine the final section offsets, and thus the final output 5370 // file size. Note we finalize the .shstrab last, to allow the 5371 // after_input_section sections to modify their section-names before 5372 // writing. 5373 if (this->any_postprocessing_sections_) 5374 { 5375 off_t off = this->output_file_size_; 5376 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS); 5377 5378 // Now that we've finalized the names, we can finalize the shstrab. 5379 off = 5380 this->set_section_offsets(off, 5381 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS); 5382 5383 if (off > this->output_file_size_) 5384 { 5385 of->resize(off); 5386 this->output_file_size_ = off; 5387 } 5388 } 5389 5390 for (Section_list::const_iterator p = this->section_list_.begin(); 5391 p != this->section_list_.end(); 5392 ++p) 5393 { 5394 if ((*p)->after_input_sections()) 5395 (*p)->write(of); 5396 } 5397 5398 this->section_headers_->write(of); 5399 } 5400 5401 // If a tree-style build ID was requested, the parallel part of that computation 5402 // is already done, and the final hash-of-hashes is computed here. For other 5403 // types of build IDs, all the work is done here. 5404 5405 void 5406 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes, 5407 size_t size_of_hashes) const 5408 { 5409 if (this->build_id_note_ == NULL) 5410 return; 5411 5412 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(), 5413 this->build_id_note_->data_size()); 5414 5415 if (array_of_hashes == NULL) 5416 { 5417 const size_t output_file_size = this->output_file_size(); 5418 const unsigned char* iv = of->get_input_view(0, output_file_size); 5419 const char* style = parameters->options().build_id(); 5420 5421 // If we get here with style == "tree" then the output must be 5422 // too small for chunking, and we use SHA-1 in that case. 5423 if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) 5424 sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); 5425 else if (strcmp(style, "md5") == 0) 5426 md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); 5427 else 5428 gold_unreachable(); 5429 5430 of->free_input_view(0, output_file_size, iv); 5431 } 5432 else 5433 { 5434 // Non-overlapping substrings of the output file have been hashed. 5435 // Compute SHA-1 hash of the hashes. 5436 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes), 5437 size_of_hashes, ov); 5438 delete[] array_of_hashes; 5439 } 5440 5441 of->write_output_view(this->build_id_note_->offset(), 5442 this->build_id_note_->data_size(), 5443 ov); 5444 } 5445 5446 // Write out a binary file. This is called after the link is 5447 // complete. IN is the temporary output file we used to generate the 5448 // ELF code. We simply walk through the segments, read them from 5449 // their file offset in IN, and write them to their load address in 5450 // the output file. FIXME: with a bit more work, we could support 5451 // S-records and/or Intel hex format here. 5452 5453 void 5454 Layout::write_binary(Output_file* in) const 5455 { 5456 gold_assert(parameters->options().oformat_enum() 5457 == General_options::OBJECT_FORMAT_BINARY); 5458 5459 // Get the size of the binary file. 5460 uint64_t max_load_address = 0; 5461 for (Segment_list::const_iterator p = this->segment_list_.begin(); 5462 p != this->segment_list_.end(); 5463 ++p) 5464 { 5465 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0) 5466 { 5467 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz(); 5468 if (max_paddr > max_load_address) 5469 max_load_address = max_paddr; 5470 } 5471 } 5472 5473 Output_file out(parameters->options().output_file_name()); 5474 out.open(max_load_address); 5475 5476 for (Segment_list::const_iterator p = this->segment_list_.begin(); 5477 p != this->segment_list_.end(); 5478 ++p) 5479 { 5480 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0) 5481 { 5482 const unsigned char* vin = in->get_input_view((*p)->offset(), 5483 (*p)->filesz()); 5484 unsigned char* vout = out.get_output_view((*p)->paddr(), 5485 (*p)->filesz()); 5486 memcpy(vout, vin, (*p)->filesz()); 5487 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout); 5488 in->free_input_view((*p)->offset(), (*p)->filesz(), vin); 5489 } 5490 } 5491 5492 out.close(); 5493 } 5494 5495 // Print the output sections to the map file. 5496 5497 void 5498 Layout::print_to_mapfile(Mapfile* mapfile) const 5499 { 5500 for (Segment_list::const_iterator p = this->segment_list_.begin(); 5501 p != this->segment_list_.end(); 5502 ++p) 5503 (*p)->print_sections_to_mapfile(mapfile); 5504 for (Section_list::const_iterator p = this->unattached_section_list_.begin(); 5505 p != this->unattached_section_list_.end(); 5506 ++p) 5507 (*p)->print_to_mapfile(mapfile); 5508 } 5509 5510 // Print statistical information to stderr. This is used for --stats. 5511 5512 void 5513 Layout::print_stats() const 5514 { 5515 this->namepool_.print_stats("section name pool"); 5516 this->sympool_.print_stats("output symbol name pool"); 5517 this->dynpool_.print_stats("dynamic name pool"); 5518 5519 for (Section_list::const_iterator p = this->section_list_.begin(); 5520 p != this->section_list_.end(); 5521 ++p) 5522 (*p)->print_merge_stats(); 5523 } 5524 5525 // Write_sections_task methods. 5526 5527 // We can always run this task. 5528 5529 Task_token* 5530 Write_sections_task::is_runnable() 5531 { 5532 return NULL; 5533 } 5534 5535 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER 5536 // when finished. 5537 5538 void 5539 Write_sections_task::locks(Task_locker* tl) 5540 { 5541 tl->add(this, this->output_sections_blocker_); 5542 if (this->input_sections_blocker_ != NULL) 5543 tl->add(this, this->input_sections_blocker_); 5544 tl->add(this, this->final_blocker_); 5545 } 5546 5547 // Run the task--write out the data. 5548 5549 void 5550 Write_sections_task::run(Workqueue*) 5551 { 5552 this->layout_->write_output_sections(this->of_); 5553 } 5554 5555 // Write_data_task methods. 5556 5557 // We can always run this task. 5558 5559 Task_token* 5560 Write_data_task::is_runnable() 5561 { 5562 return NULL; 5563 } 5564 5565 // We need to unlock FINAL_BLOCKER when finished. 5566 5567 void 5568 Write_data_task::locks(Task_locker* tl) 5569 { 5570 tl->add(this, this->final_blocker_); 5571 } 5572 5573 // Run the task--write out the data. 5574 5575 void 5576 Write_data_task::run(Workqueue*) 5577 { 5578 this->layout_->write_data(this->symtab_, this->of_); 5579 } 5580 5581 // Write_symbols_task methods. 5582 5583 // We can always run this task. 5584 5585 Task_token* 5586 Write_symbols_task::is_runnable() 5587 { 5588 return NULL; 5589 } 5590 5591 // We need to unlock FINAL_BLOCKER when finished. 5592 5593 void 5594 Write_symbols_task::locks(Task_locker* tl) 5595 { 5596 tl->add(this, this->final_blocker_); 5597 } 5598 5599 // Run the task--write out the symbols. 5600 5601 void 5602 Write_symbols_task::run(Workqueue*) 5603 { 5604 this->symtab_->write_globals(this->sympool_, this->dynpool_, 5605 this->layout_->symtab_xindex(), 5606 this->layout_->dynsym_xindex(), this->of_); 5607 } 5608 5609 // Write_after_input_sections_task methods. 5610 5611 // We can only run this task after the input sections have completed. 5612 5613 Task_token* 5614 Write_after_input_sections_task::is_runnable() 5615 { 5616 if (this->input_sections_blocker_->is_blocked()) 5617 return this->input_sections_blocker_; 5618 return NULL; 5619 } 5620 5621 // We need to unlock FINAL_BLOCKER when finished. 5622 5623 void 5624 Write_after_input_sections_task::locks(Task_locker* tl) 5625 { 5626 tl->add(this, this->final_blocker_); 5627 } 5628 5629 // Run the task. 5630 5631 void 5632 Write_after_input_sections_task::run(Workqueue*) 5633 { 5634 this->layout_->write_sections_after_input_sections(this->of_); 5635 } 5636 5637 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes, 5638 // or as a "tree" where each chunk of the string is hashed and then those 5639 // hashes are put into a (much smaller) string which is hashed with sha1. 5640 // We compute a checksum over the entire file because that is simplest. 5641 5642 void 5643 Build_id_task_runner::run(Workqueue* workqueue, const Task*) 5644 { 5645 Task_token* post_hash_tasks_blocker = new Task_token(true); 5646 const Layout* layout = this->layout_; 5647 Output_file* of = this->of_; 5648 const size_t filesize = (layout->output_file_size() <= 0 ? 0 5649 : static_cast<size_t>(layout->output_file_size())); 5650 unsigned char* array_of_hashes = NULL; 5651 size_t size_of_hashes = 0; 5652 5653 if (strcmp(this->options_->build_id(), "tree") == 0 5654 && this->options_->build_id_chunk_size_for_treehash() > 0 5655 && filesize > 0 5656 && (filesize >= this->options_->build_id_min_file_size_for_treehash())) 5657 { 5658 static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16; 5659 const size_t chunk_size = 5660 this->options_->build_id_chunk_size_for_treehash(); 5661 const size_t num_hashes = ((filesize - 1) / chunk_size) + 1; 5662 post_hash_tasks_blocker->add_blockers(num_hashes); 5663 size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES; 5664 array_of_hashes = new unsigned char[size_of_hashes]; 5665 unsigned char *dst = array_of_hashes; 5666 for (size_t i = 0, src_offset = 0; i < num_hashes; 5667 i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size) 5668 { 5669 size_t size = std::min(chunk_size, filesize - src_offset); 5670 workqueue->queue(new Hash_task(of, 5671 src_offset, 5672 size, 5673 dst, 5674 post_hash_tasks_blocker)); 5675 } 5676 } 5677 5678 // Queue the final task to write the build id and close the output file. 5679 workqueue->queue(new Task_function(new Close_task_runner(this->options_, 5680 layout, 5681 of, 5682 array_of_hashes, 5683 size_of_hashes), 5684 post_hash_tasks_blocker, 5685 "Task_function Close_task_runner")); 5686 } 5687 5688 // Close_task_runner methods. 5689 5690 // Finish up the build ID computation, if necessary, and write a binary file, 5691 // if necessary. Then close the output file. 5692 5693 void 5694 Close_task_runner::run(Workqueue*, const Task*) 5695 { 5696 // At this point the multi-threaded part of the build ID computation, 5697 // if any, is done. See Build_id_task_runner. 5698 this->layout_->write_build_id(this->of_, this->array_of_hashes_, 5699 this->size_of_hashes_); 5700 5701 // If we've been asked to create a binary file, we do so here. 5702 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF) 5703 this->layout_->write_binary(this->of_); 5704 5705 this->of_->close(); 5706 } 5707 5708 // Instantiate the templates we need. We could use the configure 5709 // script to restrict this to only the ones for implemented targets. 5710 5711 #ifdef HAVE_TARGET_32_LITTLE 5712 template 5713 Output_section* 5714 Layout::init_fixed_output_section<32, false>( 5715 const char* name, 5716 elfcpp::Shdr<32, false>& shdr); 5717 #endif 5718 5719 #ifdef HAVE_TARGET_32_BIG 5720 template 5721 Output_section* 5722 Layout::init_fixed_output_section<32, true>( 5723 const char* name, 5724 elfcpp::Shdr<32, true>& shdr); 5725 #endif 5726 5727 #ifdef HAVE_TARGET_64_LITTLE 5728 template 5729 Output_section* 5730 Layout::init_fixed_output_section<64, false>( 5731 const char* name, 5732 elfcpp::Shdr<64, false>& shdr); 5733 #endif 5734 5735 #ifdef HAVE_TARGET_64_BIG 5736 template 5737 Output_section* 5738 Layout::init_fixed_output_section<64, true>( 5739 const char* name, 5740 elfcpp::Shdr<64, true>& shdr); 5741 #endif 5742 5743 #ifdef HAVE_TARGET_32_LITTLE 5744 template 5745 Output_section* 5746 Layout::layout<32, false>(Sized_relobj_file<32, false>* object, 5747 unsigned int shndx, 5748 const char* name, 5749 const elfcpp::Shdr<32, false>& shdr, 5750 unsigned int, unsigned int, off_t*); 5751 #endif 5752 5753 #ifdef HAVE_TARGET_32_BIG 5754 template 5755 Output_section* 5756 Layout::layout<32, true>(Sized_relobj_file<32, true>* object, 5757 unsigned int shndx, 5758 const char* name, 5759 const elfcpp::Shdr<32, true>& shdr, 5760 unsigned int, unsigned int, off_t*); 5761 #endif 5762 5763 #ifdef HAVE_TARGET_64_LITTLE 5764 template 5765 Output_section* 5766 Layout::layout<64, false>(Sized_relobj_file<64, false>* object, 5767 unsigned int shndx, 5768 const char* name, 5769 const elfcpp::Shdr<64, false>& shdr, 5770 unsigned int, unsigned int, off_t*); 5771 #endif 5772 5773 #ifdef HAVE_TARGET_64_BIG 5774 template 5775 Output_section* 5776 Layout::layout<64, true>(Sized_relobj_file<64, true>* object, 5777 unsigned int shndx, 5778 const char* name, 5779 const elfcpp::Shdr<64, true>& shdr, 5780 unsigned int, unsigned int, off_t*); 5781 #endif 5782 5783 #ifdef HAVE_TARGET_32_LITTLE 5784 template 5785 Output_section* 5786 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object, 5787 unsigned int reloc_shndx, 5788 const elfcpp::Shdr<32, false>& shdr, 5789 Output_section* data_section, 5790 Relocatable_relocs* rr); 5791 #endif 5792 5793 #ifdef HAVE_TARGET_32_BIG 5794 template 5795 Output_section* 5796 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object, 5797 unsigned int reloc_shndx, 5798 const elfcpp::Shdr<32, true>& shdr, 5799 Output_section* data_section, 5800 Relocatable_relocs* rr); 5801 #endif 5802 5803 #ifdef HAVE_TARGET_64_LITTLE 5804 template 5805 Output_section* 5806 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object, 5807 unsigned int reloc_shndx, 5808 const elfcpp::Shdr<64, false>& shdr, 5809 Output_section* data_section, 5810 Relocatable_relocs* rr); 5811 #endif 5812 5813 #ifdef HAVE_TARGET_64_BIG 5814 template 5815 Output_section* 5816 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object, 5817 unsigned int reloc_shndx, 5818 const elfcpp::Shdr<64, true>& shdr, 5819 Output_section* data_section, 5820 Relocatable_relocs* rr); 5821 #endif 5822 5823 #ifdef HAVE_TARGET_32_LITTLE 5824 template 5825 void 5826 Layout::layout_group<32, false>(Symbol_table* symtab, 5827 Sized_relobj_file<32, false>* object, 5828 unsigned int, 5829 const char* group_section_name, 5830 const char* signature, 5831 const elfcpp::Shdr<32, false>& shdr, 5832 elfcpp::Elf_Word flags, 5833 std::vector<unsigned int>* shndxes); 5834 #endif 5835 5836 #ifdef HAVE_TARGET_32_BIG 5837 template 5838 void 5839 Layout::layout_group<32, true>(Symbol_table* symtab, 5840 Sized_relobj_file<32, true>* object, 5841 unsigned int, 5842 const char* group_section_name, 5843 const char* signature, 5844 const elfcpp::Shdr<32, true>& shdr, 5845 elfcpp::Elf_Word flags, 5846 std::vector<unsigned int>* shndxes); 5847 #endif 5848 5849 #ifdef HAVE_TARGET_64_LITTLE 5850 template 5851 void 5852 Layout::layout_group<64, false>(Symbol_table* symtab, 5853 Sized_relobj_file<64, false>* object, 5854 unsigned int, 5855 const char* group_section_name, 5856 const char* signature, 5857 const elfcpp::Shdr<64, false>& shdr, 5858 elfcpp::Elf_Word flags, 5859 std::vector<unsigned int>* shndxes); 5860 #endif 5861 5862 #ifdef HAVE_TARGET_64_BIG 5863 template 5864 void 5865 Layout::layout_group<64, true>(Symbol_table* symtab, 5866 Sized_relobj_file<64, true>* object, 5867 unsigned int, 5868 const char* group_section_name, 5869 const char* signature, 5870 const elfcpp::Shdr<64, true>& shdr, 5871 elfcpp::Elf_Word flags, 5872 std::vector<unsigned int>* shndxes); 5873 #endif 5874 5875 #ifdef HAVE_TARGET_32_LITTLE 5876 template 5877 Output_section* 5878 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object, 5879 const unsigned char* symbols, 5880 off_t symbols_size, 5881 const unsigned char* symbol_names, 5882 off_t symbol_names_size, 5883 unsigned int shndx, 5884 const elfcpp::Shdr<32, false>& shdr, 5885 unsigned int reloc_shndx, 5886 unsigned int reloc_type, 5887 off_t* off); 5888 #endif 5889 5890 #ifdef HAVE_TARGET_32_BIG 5891 template 5892 Output_section* 5893 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object, 5894 const unsigned char* symbols, 5895 off_t symbols_size, 5896 const unsigned char* symbol_names, 5897 off_t symbol_names_size, 5898 unsigned int shndx, 5899 const elfcpp::Shdr<32, true>& shdr, 5900 unsigned int reloc_shndx, 5901 unsigned int reloc_type, 5902 off_t* off); 5903 #endif 5904 5905 #ifdef HAVE_TARGET_64_LITTLE 5906 template 5907 Output_section* 5908 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object, 5909 const unsigned char* symbols, 5910 off_t symbols_size, 5911 const unsigned char* symbol_names, 5912 off_t symbol_names_size, 5913 unsigned int shndx, 5914 const elfcpp::Shdr<64, false>& shdr, 5915 unsigned int reloc_shndx, 5916 unsigned int reloc_type, 5917 off_t* off); 5918 #endif 5919 5920 #ifdef HAVE_TARGET_64_BIG 5921 template 5922 Output_section* 5923 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object, 5924 const unsigned char* symbols, 5925 off_t symbols_size, 5926 const unsigned char* symbol_names, 5927 off_t symbol_names_size, 5928 unsigned int shndx, 5929 const elfcpp::Shdr<64, true>& shdr, 5930 unsigned int reloc_shndx, 5931 unsigned int reloc_type, 5932 off_t* off); 5933 #endif 5934 5935 #ifdef HAVE_TARGET_32_LITTLE 5936 template 5937 void 5938 Layout::add_to_gdb_index(bool is_type_unit, 5939 Sized_relobj<32, false>* object, 5940 const unsigned char* symbols, 5941 off_t symbols_size, 5942 unsigned int shndx, 5943 unsigned int reloc_shndx, 5944 unsigned int reloc_type); 5945 #endif 5946 5947 #ifdef HAVE_TARGET_32_BIG 5948 template 5949 void 5950 Layout::add_to_gdb_index(bool is_type_unit, 5951 Sized_relobj<32, true>* object, 5952 const unsigned char* symbols, 5953 off_t symbols_size, 5954 unsigned int shndx, 5955 unsigned int reloc_shndx, 5956 unsigned int reloc_type); 5957 #endif 5958 5959 #ifdef HAVE_TARGET_64_LITTLE 5960 template 5961 void 5962 Layout::add_to_gdb_index(bool is_type_unit, 5963 Sized_relobj<64, false>* object, 5964 const unsigned char* symbols, 5965 off_t symbols_size, 5966 unsigned int shndx, 5967 unsigned int reloc_shndx, 5968 unsigned int reloc_type); 5969 #endif 5970 5971 #ifdef HAVE_TARGET_64_BIG 5972 template 5973 void 5974 Layout::add_to_gdb_index(bool is_type_unit, 5975 Sized_relobj<64, true>* object, 5976 const unsigned char* symbols, 5977 off_t symbols_size, 5978 unsigned int shndx, 5979 unsigned int reloc_shndx, 5980 unsigned int reloc_type); 5981 #endif 5982 5983 } // End namespace gold. 5984