layout.h revision 1.7
1// layout.h -- lay out output file sections for gold -*- C++ -*- 2 3// Copyright (C) 2006-2020 Free Software Foundation, Inc. 4// Written by Ian Lance Taylor <iant@google.com>. 5 6// This file is part of gold. 7 8// This program is free software; you can redistribute it and/or modify 9// it under the terms of the GNU General Public License as published by 10// the Free Software Foundation; either version 3 of the License, or 11// (at your option) any later version. 12 13// This program is distributed in the hope that it will be useful, 14// but WITHOUT ANY WARRANTY; without even the implied warranty of 15// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16// GNU General Public License for more details. 17 18// You should have received a copy of the GNU General Public License 19// along with this program; if not, write to the Free Software 20// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 21// MA 02110-1301, USA. 22 23#ifndef GOLD_LAYOUT_H 24#define GOLD_LAYOUT_H 25 26#include <cstring> 27#include <list> 28#include <map> 29#include <string> 30#include <utility> 31#include <vector> 32 33#include "script.h" 34#include "workqueue.h" 35#include "object.h" 36#include "dynobj.h" 37#include "stringpool.h" 38 39namespace gold 40{ 41 42class General_options; 43class Incremental_inputs; 44class Incremental_binary; 45class Input_objects; 46class Mapfile; 47class Symbol_table; 48class Output_section_data; 49class Output_section; 50class Output_section_headers; 51class Output_segment_headers; 52class Output_file_header; 53class Output_segment; 54class Output_data; 55class Output_data_reloc_generic; 56class Output_data_dynamic; 57class Output_symtab_xindex; 58class Output_reduced_debug_abbrev_section; 59class Output_reduced_debug_info_section; 60class Eh_frame; 61class Gdb_index; 62class Target; 63struct Timespec; 64 65// Return TRUE if SECNAME is the name of a compressed debug section. 66extern bool 67is_compressed_debug_section(const char* secname); 68 69// Return the name of the corresponding uncompressed debug section. 70extern std::string 71corresponding_uncompressed_section_name(std::string secname); 72 73// Maintain a list of free space within a section, segment, or file. 74// Used for incremental update links. 75 76class Free_list 77{ 78 public: 79 struct Free_list_node 80 { 81 Free_list_node(off_t start, off_t end) 82 : start_(start), end_(end) 83 { } 84 off_t start_; 85 off_t end_; 86 }; 87 typedef std::list<Free_list_node>::const_iterator Const_iterator; 88 89 Free_list() 90 : list_(), last_remove_(list_.begin()), extend_(false), length_(0), 91 min_hole_(0) 92 { } 93 94 // Initialize the free list for a section of length LEN. 95 // If EXTEND is true, free space may be allocated past the end. 96 void 97 init(off_t len, bool extend); 98 99 // Set the minimum hole size that is allowed when allocating 100 // from the free list. 101 void 102 set_min_hole_size(off_t min_hole) 103 { this->min_hole_ = min_hole; } 104 105 // Remove a chunk from the free list. 106 void 107 remove(off_t start, off_t end); 108 109 // Allocate a chunk of space from the free list of length LEN, 110 // with alignment ALIGN, and minimum offset MINOFF. 111 off_t 112 allocate(off_t len, uint64_t align, off_t minoff); 113 114 // Return an iterator for the beginning of the free list. 115 Const_iterator 116 begin() const 117 { return this->list_.begin(); } 118 119 // Return an iterator for the end of the free list. 120 Const_iterator 121 end() const 122 { return this->list_.end(); } 123 124 // Dump the free list (for debugging). 125 void 126 dump(); 127 128 // Print usage statistics. 129 static void 130 print_stats(); 131 132 private: 133 typedef std::list<Free_list_node>::iterator Iterator; 134 135 // The free list. 136 std::list<Free_list_node> list_; 137 138 // The last node visited during a remove operation. 139 Iterator last_remove_; 140 141 // Whether we can extend past the original length. 142 bool extend_; 143 144 // The total length of the section, segment, or file. 145 off_t length_; 146 147 // The minimum hole size allowed. When allocating from the free list, 148 // we must not leave a hole smaller than this. 149 off_t min_hole_; 150 151 // Statistics: 152 // The total number of free lists used. 153 static unsigned int num_lists; 154 // The total number of free list nodes used. 155 static unsigned int num_nodes; 156 // The total number of calls to Free_list::remove. 157 static unsigned int num_removes; 158 // The total number of nodes visited during calls to Free_list::remove. 159 static unsigned int num_remove_visits; 160 // The total number of calls to Free_list::allocate. 161 static unsigned int num_allocates; 162 // The total number of nodes visited during calls to Free_list::allocate. 163 static unsigned int num_allocate_visits; 164}; 165 166// This task function handles mapping the input sections to output 167// sections and laying them out in memory. 168 169class Layout_task_runner : public Task_function_runner 170{ 171 public: 172 // OPTIONS is the command line options, INPUT_OBJECTS is the list of 173 // input objects, SYMTAB is the symbol table, LAYOUT is the layout 174 // object. 175 Layout_task_runner(const General_options& options, 176 const Input_objects* input_objects, 177 Symbol_table* symtab, 178 Target* target, 179 Layout* layout, 180 Mapfile* mapfile) 181 : options_(options), input_objects_(input_objects), symtab_(symtab), 182 target_(target), layout_(layout), mapfile_(mapfile) 183 { } 184 185 // Run the operation. 186 void 187 run(Workqueue*, const Task*); 188 189 private: 190 Layout_task_runner(const Layout_task_runner&); 191 Layout_task_runner& operator=(const Layout_task_runner&); 192 193 const General_options& options_; 194 const Input_objects* input_objects_; 195 Symbol_table* symtab_; 196 Target* target_; 197 Layout* layout_; 198 Mapfile* mapfile_; 199}; 200 201// This class holds information about the comdat group or 202// .gnu.linkonce section that will be kept for a given signature. 203 204class Kept_section 205{ 206 private: 207 // For a comdat group, we build a mapping from the name of each 208 // section in the group to the section index and the size in object. 209 // When we discard a group in some other object file, we use this 210 // map to figure out which kept section the discarded section is 211 // associated with. We then use that mapping when processing relocs 212 // against discarded sections. 213 struct Comdat_section_info 214 { 215 // The section index. 216 unsigned int shndx; 217 // The section size. 218 uint64_t size; 219 220 Comdat_section_info(unsigned int a_shndx, uint64_t a_size) 221 : shndx(a_shndx), size(a_size) 222 { } 223 }; 224 225 // Most comdat groups have only one or two sections, so we use a 226 // std::map rather than an Unordered_map to optimize for that case 227 // without paying too heavily for groups with more sections. 228 typedef std::map<std::string, Comdat_section_info> Comdat_group; 229 230 public: 231 Kept_section() 232 : object_(NULL), shndx_(0), is_comdat_(false), is_group_name_(false) 233 { this->u_.linkonce_size = 0; } 234 235 // We need to support copies for the signature map in the Layout 236 // object, but we should never copy an object after it has been 237 // marked as a comdat section. 238 Kept_section(const Kept_section& k) 239 : object_(k.object_), shndx_(k.shndx_), is_comdat_(false), 240 is_group_name_(k.is_group_name_) 241 { 242 gold_assert(!k.is_comdat_); 243 this->u_.linkonce_size = 0; 244 } 245 246 ~Kept_section() 247 { 248 if (this->is_comdat_) 249 delete this->u_.group_sections; 250 } 251 252 // The object where this section lives. 253 Relobj* 254 object() const 255 { return this->object_; } 256 257 // Set the object. 258 void 259 set_object(Relobj* object) 260 { 261 gold_assert(this->object_ == NULL); 262 this->object_ = object; 263 } 264 265 // The section index. 266 unsigned int 267 shndx() const 268 { return this->shndx_; } 269 270 // Set the section index. 271 void 272 set_shndx(unsigned int shndx) 273 { 274 gold_assert(this->shndx_ == 0); 275 this->shndx_ = shndx; 276 } 277 278 // Whether this is a comdat group. 279 bool 280 is_comdat() const 281 { return this->is_comdat_; } 282 283 // Set that this is a comdat group. 284 void 285 set_is_comdat() 286 { 287 gold_assert(!this->is_comdat_); 288 this->is_comdat_ = true; 289 this->u_.group_sections = new Comdat_group(); 290 } 291 292 // Whether this is associated with the name of a group or section 293 // rather than the symbol name derived from a linkonce section. 294 bool 295 is_group_name() const 296 { return this->is_group_name_; } 297 298 // Note that this represents a comdat group rather than a single 299 // linkonce section. 300 void 301 set_is_group_name() 302 { this->is_group_name_ = true; } 303 304 // Add a section to the group list. 305 void 306 add_comdat_section(const std::string& name, unsigned int shndx, 307 uint64_t size) 308 { 309 gold_assert(this->is_comdat_); 310 Comdat_section_info sinfo(shndx, size); 311 this->u_.group_sections->insert(std::make_pair(name, sinfo)); 312 } 313 314 // Look for a section name in the group list, and return whether it 315 // was found. If found, returns the section index and size. 316 bool 317 find_comdat_section(const std::string& name, unsigned int* pshndx, 318 uint64_t* psize) const 319 { 320 gold_assert(this->is_comdat_); 321 Comdat_group::const_iterator p = this->u_.group_sections->find(name); 322 if (p == this->u_.group_sections->end()) 323 return false; 324 *pshndx = p->second.shndx; 325 *psize = p->second.size; 326 return true; 327 } 328 329 // If there is only one section in the group list, return true, and 330 // return the section index and size. 331 bool 332 find_single_comdat_section(unsigned int* pshndx, uint64_t* psize) const 333 { 334 gold_assert(this->is_comdat_); 335 if (this->u_.group_sections->size() != 1) 336 return false; 337 Comdat_group::const_iterator p = this->u_.group_sections->begin(); 338 *pshndx = p->second.shndx; 339 *psize = p->second.size; 340 return true; 341 } 342 343 // Return the size of a linkonce section. 344 uint64_t 345 linkonce_size() const 346 { 347 gold_assert(!this->is_comdat_); 348 return this->u_.linkonce_size; 349 } 350 351 // Set the size of a linkonce section. 352 void 353 set_linkonce_size(uint64_t size) 354 { 355 gold_assert(!this->is_comdat_); 356 this->u_.linkonce_size = size; 357 } 358 359 private: 360 // No assignment. 361 Kept_section& operator=(const Kept_section&); 362 363 // The object containing the comdat group or .gnu.linkonce section. 364 Relobj* object_; 365 // Index of the group section for comdats and the section itself for 366 // .gnu.linkonce. 367 unsigned int shndx_; 368 // True if this is for a comdat group rather than a .gnu.linkonce 369 // section. 370 bool is_comdat_; 371 // The Kept_sections are values of a mapping, that maps names to 372 // them. This field is true if this struct is associated with the 373 // name of a comdat or .gnu.linkonce, false if it is associated with 374 // the name of a symbol obtained from the .gnu.linkonce.* name 375 // through some heuristics. 376 bool is_group_name_; 377 union 378 { 379 // If the is_comdat_ field is true, this holds a map from names of 380 // the sections in the group to section indexes in object_ and to 381 // section sizes. 382 Comdat_group* group_sections; 383 // If the is_comdat_ field is false, this holds the size of the 384 // single section. 385 uint64_t linkonce_size; 386 } u_; 387}; 388 389// The ordering for output sections. This controls how output 390// sections are ordered within a PT_LOAD output segment. 391 392enum Output_section_order 393{ 394 // Unspecified. Used for non-load segments. Also used for the file 395 // and segment headers. 396 ORDER_INVALID, 397 398 // The PT_INTERP section should come first, so that the dynamic 399 // linker can pick it up quickly. 400 ORDER_INTERP, 401 402 // Loadable read-only note sections come next so that the PT_NOTE 403 // segment is on the first page of the executable. 404 ORDER_RO_NOTE, 405 406 // Put read-only sections used by the dynamic linker early in the 407 // executable to minimize paging. 408 ORDER_DYNAMIC_LINKER, 409 410 // Put reloc sections used by the dynamic linker after other 411 // sections used by the dynamic linker; otherwise, objcopy and strip 412 // get confused. 413 ORDER_DYNAMIC_RELOCS, 414 415 // Put the PLT reloc section after the other dynamic relocs; 416 // otherwise, prelink gets confused. 417 ORDER_DYNAMIC_PLT_RELOCS, 418 419 // The .init section. 420 ORDER_INIT, 421 422 // The PLT. 423 ORDER_PLT, 424 425 // The hot text sections, prefixed by .text.hot. 426 ORDER_TEXT_HOT, 427 428 // The regular text sections. 429 ORDER_TEXT, 430 431 // The startup text sections, prefixed by .text.startup. 432 ORDER_TEXT_STARTUP, 433 434 // The startup text sections, prefixed by .text.startup. 435 ORDER_TEXT_EXIT, 436 437 // The unlikely text sections, prefixed by .text.unlikely. 438 ORDER_TEXT_UNLIKELY, 439 440 // The .fini section. 441 ORDER_FINI, 442 443 // The read-only sections. 444 ORDER_READONLY, 445 446 // The exception frame sections. 447 ORDER_EHFRAME, 448 449 // The TLS sections come first in the data section. 450 ORDER_TLS_DATA, 451 ORDER_TLS_BSS, 452 453 // Local RELRO (read-only after relocation) sections come before 454 // non-local RELRO sections. This data will be fully resolved by 455 // the prelinker. 456 ORDER_RELRO_LOCAL, 457 458 // Non-local RELRO sections are grouped together after local RELRO 459 // sections. All RELRO sections must be adjacent so that they can 460 // all be put into a PT_GNU_RELRO segment. 461 ORDER_RELRO, 462 463 // We permit marking exactly one output section as the last RELRO 464 // section. We do this so that the read-only GOT can be adjacent to 465 // the writable GOT. 466 ORDER_RELRO_LAST, 467 468 // Similarly, we permit marking exactly one output section as the 469 // first non-RELRO section. 470 ORDER_NON_RELRO_FIRST, 471 472 // The regular data sections come after the RELRO sections. 473 ORDER_DATA, 474 475 // Large data sections normally go in large data segments. 476 ORDER_LARGE_DATA, 477 478 // Group writable notes so that we can have a single PT_NOTE 479 // segment. 480 ORDER_RW_NOTE, 481 482 // The small data sections must be at the end of the data sections, 483 // so that they can be adjacent to the small BSS sections. 484 ORDER_SMALL_DATA, 485 486 // The BSS sections start here. 487 488 // The small BSS sections must be at the start of the BSS sections, 489 // so that they can be adjacent to the small data sections. 490 ORDER_SMALL_BSS, 491 492 // The regular BSS sections. 493 ORDER_BSS, 494 495 // The large BSS sections come after the other BSS sections. 496 ORDER_LARGE_BSS, 497 498 // Maximum value. 499 ORDER_MAX 500}; 501 502// This class handles the details of laying out input sections. 503 504class Layout 505{ 506 public: 507 Layout(int number_of_input_files, Script_options*); 508 509 ~Layout() 510 { 511 delete this->relaxation_debug_check_; 512 delete this->segment_states_; 513 } 514 515 // For incremental links, record the base file to be modified. 516 void 517 set_incremental_base(Incremental_binary* base); 518 519 Incremental_binary* 520 incremental_base() 521 { return this->incremental_base_; } 522 523 // For incremental links, record the initial fixed layout of a section 524 // from the base file, and return a pointer to the Output_section. 525 template<int size, bool big_endian> 526 Output_section* 527 init_fixed_output_section(const char*, elfcpp::Shdr<size, big_endian>&); 528 529 // Given an input section SHNDX, named NAME, with data in SHDR, from 530 // the object file OBJECT, return the output section where this 531 // input section should go. RELOC_SHNDX is the index of a 532 // relocation section which applies to this section, or 0 if none, 533 // or -1U if more than one. RELOC_TYPE is the type of the 534 // relocation section if there is one. Set *OFFSET to the offset 535 // within the output section. 536 template<int size, bool big_endian> 537 Output_section* 538 layout(Sized_relobj_file<size, big_endian> *object, unsigned int shndx, 539 const char* name, const elfcpp::Shdr<size, big_endian>& shdr, 540 unsigned int sh_type, unsigned int reloc_shndx, 541 unsigned int reloc_type, off_t* offset); 542 543 std::map<Section_id, unsigned int>* 544 get_section_order_map() 545 { return &this->section_order_map_; } 546 547 // Struct to store segment info when mapping some input sections to 548 // unique segments using linker plugins. Mapping an input section to 549 // a unique segment is done by first placing such input sections in 550 // unique output sections and then mapping the output section to a 551 // unique segment. NAME is the name of the output section. FLAGS 552 // and ALIGN are the extra flags and alignment of the segment. 553 struct Unique_segment_info 554 { 555 // Identifier for the segment. ELF segments don't have names. This 556 // is used as the name of the output section mapped to the segment. 557 const char* name; 558 // Additional segment flags. 559 uint64_t flags; 560 // Segment alignment. 561 uint64_t align; 562 }; 563 564 // Mapping from input section to segment. 565 typedef std::map<Const_section_id, Unique_segment_info*> 566 Section_segment_map; 567 568 // Maps section SECN to SEGMENT s. 569 void 570 insert_section_segment_map(Const_section_id secn, Unique_segment_info *s); 571 572 // Some input sections require special ordering, for compatibility 573 // with GNU ld. Given the name of an input section, return -1 if it 574 // does not require special ordering. Otherwise, return the index 575 // by which it should be ordered compared to other input sections 576 // that require special ordering. 577 static int 578 special_ordering_of_input_section(const char* name); 579 580 bool 581 is_section_ordering_specified() 582 { return this->section_ordering_specified_; } 583 584 void 585 set_section_ordering_specified() 586 { this->section_ordering_specified_ = true; } 587 588 bool 589 is_unique_segment_for_sections_specified() const 590 { return this->unique_segment_for_sections_specified_; } 591 592 void 593 set_unique_segment_for_sections_specified() 594 { this->unique_segment_for_sections_specified_ = true; } 595 596 bool 597 is_lto_slim_object () const 598 { return this->lto_slim_object_; } 599 600 void 601 set_lto_slim_object () 602 { this->lto_slim_object_ = true; } 603 604 // For incremental updates, allocate a block of memory from the 605 // free list. Find a block starting at or after MINOFF. 606 off_t 607 allocate(off_t len, uint64_t align, off_t minoff) 608 { return this->free_list_.allocate(len, align, minoff); } 609 610 unsigned int 611 find_section_order_index(const std::string&); 612 613 // Read the sequence of input sections from the file specified with 614 // linker option --section-ordering-file. 615 void 616 read_layout_from_file(); 617 618 // Layout an input reloc section when doing a relocatable link. The 619 // section is RELOC_SHNDX in OBJECT, with data in SHDR. 620 // DATA_SECTION is the reloc section to which it refers. RR is the 621 // relocatable information. 622 template<int size, bool big_endian> 623 Output_section* 624 layout_reloc(Sized_relobj_file<size, big_endian>* object, 625 unsigned int reloc_shndx, 626 const elfcpp::Shdr<size, big_endian>& shdr, 627 Output_section* data_section, 628 Relocatable_relocs* rr); 629 630 // Layout a group section when doing a relocatable link. 631 template<int size, bool big_endian> 632 void 633 layout_group(Symbol_table* symtab, 634 Sized_relobj_file<size, big_endian>* object, 635 unsigned int group_shndx, 636 const char* group_section_name, 637 const char* signature, 638 const elfcpp::Shdr<size, big_endian>& shdr, 639 elfcpp::Elf_Word flags, 640 std::vector<unsigned int>* shndxes); 641 642 // Like layout, only for exception frame sections. OBJECT is an 643 // object file. SYMBOLS is the contents of the symbol table 644 // section, with size SYMBOLS_SIZE. SYMBOL_NAMES is the contents of 645 // the symbol name section, with size SYMBOL_NAMES_SIZE. SHNDX is a 646 // .eh_frame section in OBJECT. SHDR is the section header. 647 // RELOC_SHNDX is the index of a relocation section which applies to 648 // this section, or 0 if none, or -1U if more than one. RELOC_TYPE 649 // is the type of the relocation section if there is one. This 650 // returns the output section, and sets *OFFSET to the offset. 651 template<int size, bool big_endian> 652 Output_section* 653 layout_eh_frame(Sized_relobj_file<size, big_endian>* object, 654 const unsigned char* symbols, 655 off_t symbols_size, 656 const unsigned char* symbol_names, 657 off_t symbol_names_size, 658 unsigned int shndx, 659 const elfcpp::Shdr<size, big_endian>& shdr, 660 unsigned int reloc_shndx, unsigned int reloc_type, 661 off_t* offset); 662 663 // After processing all input files, we call this to make sure that 664 // the optimized .eh_frame sections have been added to the output 665 // section. 666 void 667 finalize_eh_frame_section(); 668 669 // Add .eh_frame information for a PLT. The FDE must start with a 670 // 4-byte PC-relative reference to the start of the PLT, followed by 671 // a 4-byte size of PLT. 672 void 673 add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, 674 size_t cie_length, const unsigned char* fde_data, 675 size_t fde_length); 676 677 // Remove all post-map .eh_frame information for a PLT. 678 void 679 remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, 680 size_t cie_length); 681 682 // Scan a .debug_info or .debug_types section, and add summary 683 // information to the .gdb_index section. 684 template<int size, bool big_endian> 685 void 686 add_to_gdb_index(bool is_type_unit, 687 Sized_relobj<size, big_endian>* object, 688 const unsigned char* symbols, 689 off_t symbols_size, 690 unsigned int shndx, 691 unsigned int reloc_shndx, 692 unsigned int reloc_type); 693 694 // Handle a GNU stack note. This is called once per input object 695 // file. SEEN_GNU_STACK is true if the object file has a 696 // .note.GNU-stack section. GNU_STACK_FLAGS is the section flags 697 // from that section if there was one. 698 void 699 layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags, 700 const Object*); 701 702 // Layout a .note.gnu.property section. 703 void 704 layout_gnu_property(unsigned int note_type, 705 unsigned int pr_type, 706 size_t pr_datasz, 707 const unsigned char* pr_data, 708 const Object* object); 709 710 // Merge per-object properties with program properties. 711 void 712 merge_gnu_properties(const Object* object); 713 714 // Add a target-specific property for the output .note.gnu.property section. 715 void 716 add_gnu_property(unsigned int note_type, 717 unsigned int pr_type, 718 size_t pr_datasz, 719 const unsigned char* pr_data); 720 721 // Add an Output_section_data to the layout. This is used for 722 // special sections like the GOT section. ORDER is where the 723 // section should wind up in the output segment. IS_RELRO is true 724 // for relro sections. 725 Output_section* 726 add_output_section_data(const char* name, elfcpp::Elf_Word type, 727 elfcpp::Elf_Xword flags, 728 Output_section_data*, Output_section_order order, 729 bool is_relro); 730 731 // Increase the size of the relro segment by this much. 732 void 733 increase_relro(unsigned int s) 734 { this->increase_relro_ += s; } 735 736 // Create dynamic sections if necessary. 737 void 738 create_initial_dynamic_sections(Symbol_table*); 739 740 // Define __start and __stop symbols for output sections. 741 void 742 define_section_symbols(Symbol_table*); 743 744 // Create automatic note sections. 745 void 746 create_notes(); 747 748 // Create sections for linker scripts. 749 void 750 create_script_sections() 751 { this->script_options_->create_script_sections(this); } 752 753 // Define symbols from any linker script. 754 void 755 define_script_symbols(Symbol_table* symtab) 756 { this->script_options_->add_symbols_to_table(symtab); } 757 758 // Define symbols for group signatures. 759 void 760 define_group_signatures(Symbol_table*); 761 762 // Return the Stringpool used for symbol names. 763 const Stringpool* 764 sympool() const 765 { return &this->sympool_; } 766 767 // Return the Stringpool used for dynamic symbol names and dynamic 768 // tags. 769 const Stringpool* 770 dynpool() const 771 { return &this->dynpool_; } 772 773 // Return the .dynamic output section. This is only valid after the 774 // layout has been finalized. 775 Output_section* 776 dynamic_section() const 777 { return this->dynamic_section_; } 778 779 // Return the symtab_xindex section used to hold large section 780 // indexes for the normal symbol table. 781 Output_symtab_xindex* 782 symtab_xindex() const 783 { return this->symtab_xindex_; } 784 785 // Return the dynsym_xindex section used to hold large section 786 // indexes for the dynamic symbol table. 787 Output_symtab_xindex* 788 dynsym_xindex() const 789 { return this->dynsym_xindex_; } 790 791 // Return whether a section is a .gnu.linkonce section, given the 792 // section name. 793 static inline bool 794 is_linkonce(const char* name) 795 { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; } 796 797 // Whether we have added an input section. 798 bool 799 have_added_input_section() const 800 { return this->have_added_input_section_; } 801 802 // Return true if a section is a debugging section. 803 static inline bool 804 is_debug_info_section(const char* name) 805 { 806 // Debugging sections can only be recognized by name. 807 return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0 808 || strncmp(name, ".zdebug", sizeof(".zdebug") - 1) == 0 809 || strncmp(name, ".gnu.linkonce.wi.", 810 sizeof(".gnu.linkonce.wi.") - 1) == 0 811 || strncmp(name, ".line", sizeof(".line") - 1) == 0 812 || strncmp(name, ".stab", sizeof(".stab") - 1) == 0 813 || strncmp(name, ".pdr", sizeof(".pdr") - 1) == 0); 814 } 815 816 // Return true if RELOBJ is an input file whose base name matches 817 // FILE_NAME. The base name must have an extension of ".o", and 818 // must be exactly FILE_NAME.o or FILE_NAME, one character, ".o". 819 static bool 820 match_file_name(const Relobj* relobj, const char* file_name); 821 822 // Return whether section SHNDX in RELOBJ is a .ctors/.dtors section 823 // with more than one word being mapped to a .init_array/.fini_array 824 // section. 825 bool 826 is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const; 827 828 // Check if a comdat group or .gnu.linkonce section with the given 829 // NAME is selected for the link. If there is already a section, 830 // *KEPT_SECTION is set to point to the signature and the function 831 // returns false. Otherwise, OBJECT, SHNDX,IS_COMDAT, and 832 // IS_GROUP_NAME are recorded for this NAME in the layout object, 833 // *KEPT_SECTION is set to the internal copy and the function return 834 // false. 835 bool 836 find_or_add_kept_section(const std::string& name, Relobj* object, 837 unsigned int shndx, bool is_comdat, 838 bool is_group_name, Kept_section** kept_section); 839 840 // Finalize the layout after all the input sections have been added. 841 off_t 842 finalize(const Input_objects*, Symbol_table*, Target*, const Task*); 843 844 // Return whether any sections require postprocessing. 845 bool 846 any_postprocessing_sections() const 847 { return this->any_postprocessing_sections_; } 848 849 // Return the size of the output file. 850 off_t 851 output_file_size() const 852 { return this->output_file_size_; } 853 854 // Return the TLS segment. This will return NULL if there isn't 855 // one. 856 Output_segment* 857 tls_segment() const 858 { return this->tls_segment_; } 859 860 // Return the normal symbol table. 861 Output_section* 862 symtab_section() const 863 { 864 gold_assert(this->symtab_section_ != NULL); 865 return this->symtab_section_; 866 } 867 868 // Return the file offset of the normal symbol table. 869 off_t 870 symtab_section_offset() const; 871 872 // Return the section index of the normal symbol tabl.e 873 unsigned int 874 symtab_section_shndx() const; 875 876 // Return the dynamic symbol table. 877 Output_section* 878 dynsym_section() const 879 { 880 gold_assert(this->dynsym_section_ != NULL); 881 return this->dynsym_section_; 882 } 883 884 // Return the dynamic tags. 885 Output_data_dynamic* 886 dynamic_data() const 887 { return this->dynamic_data_; } 888 889 // Write out the output sections. 890 void 891 write_output_sections(Output_file* of) const; 892 893 // Write out data not associated with an input file or the symbol 894 // table. 895 void 896 write_data(const Symbol_table*, Output_file*) const; 897 898 // Write out output sections which can not be written until all the 899 // input sections are complete. 900 void 901 write_sections_after_input_sections(Output_file* of); 902 903 // Return an output section named NAME, or NULL if there is none. 904 Output_section* 905 find_output_section(const char* name) const; 906 907 // Return an output segment of type TYPE, with segment flags SET set 908 // and segment flags CLEAR clear. Return NULL if there is none. 909 Output_segment* 910 find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, 911 elfcpp::Elf_Word clear) const; 912 913 // Return the number of segments we expect to produce. 914 size_t 915 expected_segment_count() const; 916 917 // Set a flag to indicate that an object file uses the static TLS model. 918 void 919 set_has_static_tls() 920 { this->has_static_tls_ = true; } 921 922 // Return true if any object file uses the static TLS model. 923 bool 924 has_static_tls() const 925 { return this->has_static_tls_; } 926 927 // Return the options which may be set by a linker script. 928 Script_options* 929 script_options() 930 { return this->script_options_; } 931 932 const Script_options* 933 script_options() const 934 { return this->script_options_; } 935 936 // Return the object managing inputs in incremental build. NULL in 937 // non-incremental builds. 938 Incremental_inputs* 939 incremental_inputs() const 940 { return this->incremental_inputs_; } 941 942 // For the target-specific code to add dynamic tags which are common 943 // to most targets. 944 void 945 add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, 946 const Output_data* plt_rel, 947 const Output_data_reloc_generic* dyn_rel, 948 bool add_debug, bool dynrel_includes_plt); 949 950 // Add a target-specific dynamic tag with constant value. 951 void 952 add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val); 953 954 // Compute and write out the build ID if needed. 955 void 956 write_build_id(Output_file*, unsigned char*, size_t) const; 957 958 // Rewrite output file in binary format. 959 void 960 write_binary(Output_file* in) const; 961 962 // Print output sections to the map file. 963 void 964 print_to_mapfile(Mapfile*) const; 965 966 // Dump statistical information to stderr. 967 void 968 print_stats() const; 969 970 // A list of segments. 971 972 typedef std::vector<Output_segment*> Segment_list; 973 974 // A list of sections. 975 976 typedef std::vector<Output_section*> Section_list; 977 978 // The list of information to write out which is not attached to 979 // either a section or a segment. 980 typedef std::vector<Output_data*> Data_list; 981 982 // Store the allocated sections into the section list. This is used 983 // by the linker script code. 984 void 985 get_allocated_sections(Section_list*) const; 986 987 // Store the executable sections into the section list. 988 void 989 get_executable_sections(Section_list*) const; 990 991 // Make a section for a linker script to hold data. 992 Output_section* 993 make_output_section_for_script(const char* name, 994 Script_sections::Section_type section_type); 995 996 // Make a segment. This is used by the linker script code. 997 Output_segment* 998 make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags); 999 1000 // Return the number of segments. 1001 size_t 1002 segment_count() const 1003 { return this->segment_list_.size(); } 1004 1005 // Map from section flags to segment flags. 1006 static elfcpp::Elf_Word 1007 section_flags_to_segment(elfcpp::Elf_Xword flags); 1008 1009 // Attach sections to segments. 1010 void 1011 attach_sections_to_segments(const Target*); 1012 1013 // For relaxation clean up, we need to know output section data created 1014 // from a linker script. 1015 void 1016 new_output_section_data_from_script(Output_section_data* posd) 1017 { 1018 if (this->record_output_section_data_from_script_) 1019 this->script_output_section_data_list_.push_back(posd); 1020 } 1021 1022 // Return section list. 1023 const Section_list& 1024 section_list() const 1025 { return this->section_list_; } 1026 1027 // Returns TRUE iff NAME (an input section from RELOBJ) will 1028 // be mapped to an output section that should be KEPT. 1029 bool 1030 keep_input_section(const Relobj*, const char*); 1031 1032 // Add a special output object that will be recreated afresh 1033 // if there is another relaxation iteration. 1034 void 1035 add_relax_output(Output_data* data) 1036 { this->relax_output_list_.push_back(data); } 1037 1038 // Clear out (and free) everything added by add_relax_output. 1039 void 1040 reset_relax_output(); 1041 1042 private: 1043 Layout(const Layout&); 1044 Layout& operator=(const Layout&); 1045 1046 // Mapping from input section names to output section names. 1047 struct Section_name_mapping 1048 { 1049 const char* from; 1050 int fromlen; 1051 const char* to; 1052 int tolen; 1053 }; 1054 static const Section_name_mapping section_name_mapping[]; 1055 static const int section_name_mapping_count; 1056 static const Section_name_mapping text_section_name_mapping[]; 1057 static const int text_section_name_mapping_count; 1058 1059 // Find section name NAME in map and return the mapped name if found 1060 // with the length set in PLEN. 1061 static const char* match_section_name(const Section_name_mapping* map, 1062 const int count, const char* name, 1063 size_t* plen); 1064 1065 // During a relocatable link, a list of group sections and 1066 // signatures. 1067 struct Group_signature 1068 { 1069 // The group section. 1070 Output_section* section; 1071 // The signature. 1072 const char* signature; 1073 1074 Group_signature() 1075 : section(NULL), signature(NULL) 1076 { } 1077 1078 Group_signature(Output_section* sectiona, const char* signaturea) 1079 : section(sectiona), signature(signaturea) 1080 { } 1081 }; 1082 typedef std::vector<Group_signature> Group_signatures; 1083 1084 // Create a note section, filling in the header. 1085 Output_section* 1086 create_note(const char* name, int note_type, const char* section_name, 1087 size_t descsz, bool allocate, size_t* trailing_padding); 1088 1089 // Create a note section for gnu program properties. 1090 void 1091 create_gnu_properties_note(); 1092 1093 // Create a note section for gold version. 1094 void 1095 create_gold_note(); 1096 1097 // Record whether the stack must be executable, and a user-supplied size. 1098 void 1099 create_stack_segment(); 1100 1101 // Create a build ID note if needed. 1102 void 1103 create_build_id(); 1104 1105 // Link .stab and .stabstr sections. 1106 void 1107 link_stabs_sections(); 1108 1109 // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed 1110 // for the next run of incremental linking to check what has changed. 1111 void 1112 create_incremental_info_sections(Symbol_table*); 1113 1114 // Find the first read-only PT_LOAD segment, creating one if 1115 // necessary. 1116 Output_segment* 1117 find_first_load_seg(const Target*); 1118 1119 // Count the local symbols in the regular symbol table and the dynamic 1120 // symbol table, and build the respective string pools. 1121 void 1122 count_local_symbols(const Task*, const Input_objects*); 1123 1124 // Create the output sections for the symbol table. 1125 void 1126 create_symtab_sections(const Input_objects*, Symbol_table*, 1127 unsigned int, off_t*, unsigned int); 1128 1129 // Create the .shstrtab section. 1130 Output_section* 1131 create_shstrtab(); 1132 1133 // Create the section header table. 1134 void 1135 create_shdrs(const Output_section* shstrtab_section, off_t*); 1136 1137 // Create the dynamic symbol table. 1138 void 1139 create_dynamic_symtab(const Input_objects*, Symbol_table*, 1140 Output_section** pdynstr, 1141 unsigned int* plocal_dynamic_count, 1142 unsigned int* pforced_local_dynamic_count, 1143 std::vector<Symbol*>* pdynamic_symbols, 1144 Versions* versions); 1145 1146 // Assign offsets to each local portion of the dynamic symbol table. 1147 void 1148 assign_local_dynsym_offsets(const Input_objects*); 1149 1150 // Finish the .dynamic section and PT_DYNAMIC segment. 1151 void 1152 finish_dynamic_section(const Input_objects*, const Symbol_table*); 1153 1154 // Set the size of the _DYNAMIC symbol. 1155 void 1156 set_dynamic_symbol_size(const Symbol_table*); 1157 1158 // Create the .interp section and PT_INTERP segment. 1159 void 1160 create_interp(const Target* target); 1161 1162 // Create the version sections. 1163 void 1164 create_version_sections(const Versions*, 1165 const Symbol_table*, 1166 unsigned int local_symcount, 1167 const std::vector<Symbol*>& dynamic_symbols, 1168 const Output_section* dynstr); 1169 1170 template<int size, bool big_endian> 1171 void 1172 sized_create_version_sections(const Versions* versions, 1173 const Symbol_table*, 1174 unsigned int local_symcount, 1175 const std::vector<Symbol*>& dynamic_symbols, 1176 const Output_section* dynstr); 1177 1178 // Return whether to include this section in the link. 1179 template<int size, bool big_endian> 1180 bool 1181 include_section(Sized_relobj_file<size, big_endian>* object, const char* name, 1182 const elfcpp::Shdr<size, big_endian>&); 1183 1184 // Return the output section name to use given an input section 1185 // name. Set *PLEN to the length of the name. *PLEN must be 1186 // initialized to the length of NAME. 1187 static const char* 1188 output_section_name(const Relobj*, const char* name, size_t* plen); 1189 1190 // Return the number of allocated output sections. 1191 size_t 1192 allocated_output_section_count() const; 1193 1194 // Return the output section for NAME, TYPE and FLAGS. 1195 Output_section* 1196 get_output_section(const char* name, Stringpool::Key name_key, 1197 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, 1198 Output_section_order order, bool is_relro); 1199 1200 // Clear the input section flags that should not be copied to the 1201 // output section. 1202 elfcpp::Elf_Xword 1203 get_output_section_flags (elfcpp::Elf_Xword input_section_flags); 1204 1205 // Choose the output section for NAME in RELOBJ. 1206 Output_section* 1207 choose_output_section(const Relobj* relobj, const char* name, 1208 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, 1209 bool is_input_section, Output_section_order order, 1210 bool is_relro, bool is_reloc, bool match_input_spec); 1211 1212 // Create a new Output_section. 1213 Output_section* 1214 make_output_section(const char* name, elfcpp::Elf_Word type, 1215 elfcpp::Elf_Xword flags, Output_section_order order, 1216 bool is_relro); 1217 1218 // Attach a section to a segment. 1219 void 1220 attach_section_to_segment(const Target*, Output_section*); 1221 1222 // Get section order. 1223 Output_section_order 1224 default_section_order(Output_section*, bool is_relro_local); 1225 1226 // Attach an allocated section to a segment. 1227 void 1228 attach_allocated_section_to_segment(const Target*, Output_section*); 1229 1230 // Make the .eh_frame section. 1231 Output_section* 1232 make_eh_frame_section(const Relobj*); 1233 1234 // Set the final file offsets of all the segments. 1235 off_t 1236 set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx); 1237 1238 // Set the file offsets of the sections when doing a relocatable 1239 // link. 1240 off_t 1241 set_relocatable_section_offsets(Output_data*, unsigned int* pshndx); 1242 1243 // Set the final file offsets of all the sections not associated 1244 // with a segment. We set section offsets in three passes: the 1245 // first handles all allocated sections, the second sections that 1246 // require postprocessing, and the last the late-bound STRTAB 1247 // sections (probably only shstrtab, which is the one we care about 1248 // because it holds section names). 1249 enum Section_offset_pass 1250 { 1251 BEFORE_INPUT_SECTIONS_PASS, 1252 POSTPROCESSING_SECTIONS_PASS, 1253 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS 1254 }; 1255 off_t 1256 set_section_offsets(off_t, Section_offset_pass pass); 1257 1258 // Set the final section indexes of all the sections not associated 1259 // with a segment. Returns the next unused index. 1260 unsigned int 1261 set_section_indexes(unsigned int pshndx); 1262 1263 // Set the section addresses when using a script. 1264 Output_segment* 1265 set_section_addresses_from_script(Symbol_table*); 1266 1267 // Find appropriate places or orphan sections in a script. 1268 void 1269 place_orphan_sections_in_script(); 1270 1271 // Return whether SEG1 comes before SEG2 in the output file. 1272 bool 1273 segment_precedes(const Output_segment* seg1, const Output_segment* seg2); 1274 1275 // Use to save and restore segments during relaxation. 1276 typedef Unordered_map<const Output_segment*, const Output_segment*> 1277 Segment_states; 1278 1279 // Save states of current output segments. 1280 void 1281 save_segments(Segment_states*); 1282 1283 // Restore output segment states. 1284 void 1285 restore_segments(const Segment_states*); 1286 1287 // Clean up after relaxation so that it is possible to lay out the 1288 // sections and segments again. 1289 void 1290 clean_up_after_relaxation(); 1291 1292 // Doing preparation work for relaxation. This is factored out to make 1293 // Layout::finalized a bit smaller and easier to read. 1294 void 1295 prepare_for_relaxation(); 1296 1297 // Main body of the relaxation loop, which lays out the section. 1298 off_t 1299 relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**, 1300 Output_segment*, Output_segment_headers*, 1301 Output_file_header*, unsigned int*); 1302 1303 // A mapping used for kept comdats/.gnu.linkonce group signatures. 1304 typedef Unordered_map<std::string, Kept_section> Signatures; 1305 1306 // Mapping from input section name/type/flags to output section. We 1307 // use canonicalized strings here. 1308 1309 typedef std::pair<Stringpool::Key, 1310 std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key; 1311 1312 struct Hash_key 1313 { 1314 size_t 1315 operator()(const Key& k) const; 1316 }; 1317 1318 typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map; 1319 1320 // A comparison class for segments. 1321 1322 class Compare_segments 1323 { 1324 public: 1325 Compare_segments(Layout* layout) 1326 : layout_(layout) 1327 { } 1328 1329 bool 1330 operator()(const Output_segment* seg1, const Output_segment* seg2) 1331 { return this->layout_->segment_precedes(seg1, seg2); } 1332 1333 private: 1334 Layout* layout_; 1335 }; 1336 1337 typedef std::vector<Output_section_data*> Output_section_data_list; 1338 1339 // Debug checker class. 1340 class Relaxation_debug_check 1341 { 1342 public: 1343 Relaxation_debug_check() 1344 : section_infos_() 1345 { } 1346 1347 // Check that sections and special data are in reset states. 1348 void 1349 check_output_data_for_reset_values(const Layout::Section_list&, 1350 const Layout::Data_list& special_outputs, 1351 const Layout::Data_list& relax_outputs); 1352 1353 // Record information of a section list. 1354 void 1355 read_sections(const Layout::Section_list&); 1356 1357 // Verify a section list with recorded information. 1358 void 1359 verify_sections(const Layout::Section_list&); 1360 1361 private: 1362 // Information we care about a section. 1363 struct Section_info 1364 { 1365 // Output section described by this. 1366 Output_section* output_section; 1367 // Load address. 1368 uint64_t address; 1369 // Data size. 1370 off_t data_size; 1371 // File offset. 1372 off_t offset; 1373 }; 1374 1375 // Section information. 1376 std::vector<Section_info> section_infos_; 1377 }; 1378 1379 // Program properties from .note.gnu.property sections. 1380 struct Gnu_property 1381 { 1382 size_t pr_datasz; 1383 unsigned char* pr_data; 1384 }; 1385 typedef std::map<unsigned int, Gnu_property> Gnu_properties; 1386 1387 // The number of input files, for sizing tables. 1388 int number_of_input_files_; 1389 // Information set by scripts or by command line options. 1390 Script_options* script_options_; 1391 // The output section names. 1392 Stringpool namepool_; 1393 // The output symbol names. 1394 Stringpool sympool_; 1395 // The dynamic strings, if needed. 1396 Stringpool dynpool_; 1397 // The list of group sections and linkonce sections which we have seen. 1398 Signatures signatures_; 1399 // The mapping from input section name/type/flags to output sections. 1400 Section_name_map section_name_map_; 1401 // The list of output segments. 1402 Segment_list segment_list_; 1403 // The list of output sections. 1404 Section_list section_list_; 1405 // The list of output sections which are not attached to any output 1406 // segment. 1407 Section_list unattached_section_list_; 1408 // The list of unattached Output_data objects which require special 1409 // handling because they are not Output_sections. 1410 Data_list special_output_list_; 1411 // Like special_output_list_, but cleared and recreated on each 1412 // iteration of relaxation. 1413 Data_list relax_output_list_; 1414 // The section headers. 1415 Output_section_headers* section_headers_; 1416 // A pointer to the PT_TLS segment if there is one. 1417 Output_segment* tls_segment_; 1418 // A pointer to the PT_GNU_RELRO segment if there is one. 1419 Output_segment* relro_segment_; 1420 // A pointer to the PT_INTERP segment if there is one. 1421 Output_segment* interp_segment_; 1422 // A backend may increase the size of the PT_GNU_RELRO segment if 1423 // there is one. This is the amount to increase it by. 1424 unsigned int increase_relro_; 1425 // The SHT_SYMTAB output section. 1426 Output_section* symtab_section_; 1427 // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one. 1428 Output_symtab_xindex* symtab_xindex_; 1429 // The SHT_DYNSYM output section if there is one. 1430 Output_section* dynsym_section_; 1431 // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one. 1432 Output_symtab_xindex* dynsym_xindex_; 1433 // The SHT_DYNAMIC output section if there is one. 1434 Output_section* dynamic_section_; 1435 // The _DYNAMIC symbol if there is one. 1436 Symbol* dynamic_symbol_; 1437 // The dynamic data which goes into dynamic_section_. 1438 Output_data_dynamic* dynamic_data_; 1439 // The exception frame output section if there is one. 1440 Output_section* eh_frame_section_; 1441 // The exception frame data for eh_frame_section_. 1442 Eh_frame* eh_frame_data_; 1443 // Whether we have added eh_frame_data_ to the .eh_frame section. 1444 bool added_eh_frame_data_; 1445 // The exception frame header output section if there is one. 1446 Output_section* eh_frame_hdr_section_; 1447 // The data for the .gdb_index section. 1448 Gdb_index* gdb_index_data_; 1449 // The space for the build ID checksum if there is one. 1450 Output_section_data* build_id_note_; 1451 // The output section containing dwarf abbreviations 1452 Output_reduced_debug_abbrev_section* debug_abbrev_; 1453 // The output section containing the dwarf debug info tree 1454 Output_reduced_debug_info_section* debug_info_; 1455 // A list of group sections and their signatures. 1456 Group_signatures group_signatures_; 1457 // The size of the output file. 1458 off_t output_file_size_; 1459 // Whether we have added an input section to an output section. 1460 bool have_added_input_section_; 1461 // Whether we have attached the sections to the segments. 1462 bool sections_are_attached_; 1463 // Whether we have seen an object file marked to require an 1464 // executable stack. 1465 bool input_requires_executable_stack_; 1466 // Whether we have seen at least one object file with an executable 1467 // stack marker. 1468 bool input_with_gnu_stack_note_; 1469 // Whether we have seen at least one object file without an 1470 // executable stack marker. 1471 bool input_without_gnu_stack_note_; 1472 // Whether we have seen an object file that uses the static TLS model. 1473 bool has_static_tls_; 1474 // Whether any sections require postprocessing. 1475 bool any_postprocessing_sections_; 1476 // Whether we have resized the signatures_ hash table. 1477 bool resized_signatures_; 1478 // Whether we have created a .stab*str output section. 1479 bool have_stabstr_section_; 1480 // True if the input sections in the output sections should be sorted 1481 // as specified in a section ordering file. 1482 bool section_ordering_specified_; 1483 // True if some input sections need to be mapped to a unique segment, 1484 // after being mapped to a unique Output_section. 1485 bool unique_segment_for_sections_specified_; 1486 // In incremental build, holds information check the inputs and build the 1487 // .gnu_incremental_inputs section. 1488 Incremental_inputs* incremental_inputs_; 1489 // Whether we record output section data created in script 1490 bool record_output_section_data_from_script_; 1491 // Set if this is a slim LTO object not loaded with a compiler plugin 1492 bool lto_slim_object_; 1493 // List of output data that needs to be removed at relaxation clean up. 1494 Output_section_data_list script_output_section_data_list_; 1495 // Structure to save segment states before entering the relaxation loop. 1496 Segment_states* segment_states_; 1497 // A relaxation debug checker. We only create one when in debugging mode. 1498 Relaxation_debug_check* relaxation_debug_check_; 1499 // Plugins specify section_ordering using this map. This is set in 1500 // update_section_order in plugin.cc 1501 std::map<Section_id, unsigned int> section_order_map_; 1502 // This maps an input section to a unique segment. This is done by first 1503 // placing such input sections in unique output sections and then mapping 1504 // the output section to a unique segment. Unique_segment_info stores 1505 // any additional flags and alignment of the new segment. 1506 Section_segment_map section_segment_map_; 1507 // Hash a pattern to its position in the section ordering file. 1508 Unordered_map<std::string, unsigned int> input_section_position_; 1509 // Vector of glob only patterns in the section_ordering file. 1510 std::vector<std::string> input_section_glob_; 1511 // For incremental links, the base file to be modified. 1512 Incremental_binary* incremental_base_; 1513 // For incremental links, a list of free space within the file. 1514 Free_list free_list_; 1515 // Program properties. 1516 Gnu_properties gnu_properties_; 1517}; 1518 1519// This task handles writing out data in output sections which is not 1520// part of an input section, or which requires special handling. When 1521// this is done, it unblocks both output_sections_blocker and 1522// final_blocker. 1523 1524class Write_sections_task : public Task 1525{ 1526 public: 1527 Write_sections_task(const Layout* layout, Output_file* of, 1528 Task_token* output_sections_blocker, 1529 Task_token* input_sections_blocker, 1530 Task_token* final_blocker) 1531 : layout_(layout), of_(of), 1532 output_sections_blocker_(output_sections_blocker), 1533 input_sections_blocker_(input_sections_blocker), 1534 final_blocker_(final_blocker) 1535 { } 1536 1537 // The standard Task methods. 1538 1539 Task_token* 1540 is_runnable(); 1541 1542 void 1543 locks(Task_locker*); 1544 1545 void 1546 run(Workqueue*); 1547 1548 std::string 1549 get_name() const 1550 { return "Write_sections_task"; } 1551 1552 private: 1553 class Write_sections_locker; 1554 1555 const Layout* layout_; 1556 Output_file* of_; 1557 Task_token* output_sections_blocker_; 1558 Task_token* input_sections_blocker_; 1559 Task_token* final_blocker_; 1560}; 1561 1562// This task handles writing out data which is not part of a section 1563// or segment. 1564 1565class Write_data_task : public Task 1566{ 1567 public: 1568 Write_data_task(const Layout* layout, const Symbol_table* symtab, 1569 Output_file* of, Task_token* final_blocker) 1570 : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker) 1571 { } 1572 1573 // The standard Task methods. 1574 1575 Task_token* 1576 is_runnable(); 1577 1578 void 1579 locks(Task_locker*); 1580 1581 void 1582 run(Workqueue*); 1583 1584 std::string 1585 get_name() const 1586 { return "Write_data_task"; } 1587 1588 private: 1589 const Layout* layout_; 1590 const Symbol_table* symtab_; 1591 Output_file* of_; 1592 Task_token* final_blocker_; 1593}; 1594 1595// This task handles writing out the global symbols. 1596 1597class Write_symbols_task : public Task 1598{ 1599 public: 1600 Write_symbols_task(const Layout* layout, const Symbol_table* symtab, 1601 const Input_objects* /*input_objects*/, 1602 const Stringpool* sympool, const Stringpool* dynpool, 1603 Output_file* of, Task_token* final_blocker) 1604 : layout_(layout), symtab_(symtab), 1605 sympool_(sympool), dynpool_(dynpool), of_(of), 1606 final_blocker_(final_blocker) 1607 { } 1608 1609 // The standard Task methods. 1610 1611 Task_token* 1612 is_runnable(); 1613 1614 void 1615 locks(Task_locker*); 1616 1617 void 1618 run(Workqueue*); 1619 1620 std::string 1621 get_name() const 1622 { return "Write_symbols_task"; } 1623 1624 private: 1625 const Layout* layout_; 1626 const Symbol_table* symtab_; 1627 const Stringpool* sympool_; 1628 const Stringpool* dynpool_; 1629 Output_file* of_; 1630 Task_token* final_blocker_; 1631}; 1632 1633// This task handles writing out data in output sections which can't 1634// be written out until all the input sections have been handled. 1635// This is for sections whose contents is based on the contents of 1636// other output sections. 1637 1638class Write_after_input_sections_task : public Task 1639{ 1640 public: 1641 Write_after_input_sections_task(Layout* layout, Output_file* of, 1642 Task_token* input_sections_blocker, 1643 Task_token* final_blocker) 1644 : layout_(layout), of_(of), 1645 input_sections_blocker_(input_sections_blocker), 1646 final_blocker_(final_blocker) 1647 { } 1648 1649 // The standard Task methods. 1650 1651 Task_token* 1652 is_runnable(); 1653 1654 void 1655 locks(Task_locker*); 1656 1657 void 1658 run(Workqueue*); 1659 1660 std::string 1661 get_name() const 1662 { return "Write_after_input_sections_task"; } 1663 1664 private: 1665 Layout* layout_; 1666 Output_file* of_; 1667 Task_token* input_sections_blocker_; 1668 Task_token* final_blocker_; 1669}; 1670 1671// This task function handles computation of the build id. 1672// When using --build-id=tree, it schedules the tasks that 1673// compute the hashes for each chunk of the file. This task 1674// cannot run until we have finalized the size of the output 1675// file, after the completion of Write_after_input_sections_task. 1676 1677class Build_id_task_runner : public Task_function_runner 1678{ 1679 public: 1680 Build_id_task_runner(const General_options* options, const Layout* layout, 1681 Output_file* of) 1682 : options_(options), layout_(layout), of_(of) 1683 { } 1684 1685 // Run the operation. 1686 void 1687 run(Workqueue*, const Task*); 1688 1689 private: 1690 const General_options* options_; 1691 const Layout* layout_; 1692 Output_file* of_; 1693}; 1694 1695// This task function handles closing the file. 1696 1697class Close_task_runner : public Task_function_runner 1698{ 1699 public: 1700 Close_task_runner(const General_options* options, const Layout* layout, 1701 Output_file* of, unsigned char* array_of_hashes, 1702 size_t size_of_hashes) 1703 : options_(options), layout_(layout), of_(of), 1704 array_of_hashes_(array_of_hashes), size_of_hashes_(size_of_hashes) 1705 { } 1706 1707 // Run the operation. 1708 void 1709 run(Workqueue*, const Task*); 1710 1711 private: 1712 const General_options* options_; 1713 const Layout* layout_; 1714 Output_file* of_; 1715 unsigned char* const array_of_hashes_; 1716 const size_t size_of_hashes_; 1717}; 1718 1719// A small helper function to align an address. 1720 1721inline uint64_t 1722align_address(uint64_t address, uint64_t addralign) 1723{ 1724 if (addralign != 0) 1725 address = (address + addralign - 1) &~ (addralign - 1); 1726 return address; 1727} 1728 1729} // End namespace gold. 1730 1731#endif // !defined(GOLD_LAYOUT_H) 1732