ld/ldlang.h

   1 /* ldlang.h - linker command language support
   2    Copyright (C) 1991-2020 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #ifndef LDLANG_H
  22 #define LDLANG_H
  23
  24 #define DEFAULT_MEMORY_REGION   "*default*"
  25
  26 typedef enum
  27 {
  28   lang_input_file_is_l_enum,
  29   lang_input_file_is_symbols_only_enum,
  30   lang_input_file_is_marker_enum,
  31   lang_input_file_is_fake_enum,
  32   lang_input_file_is_search_file_enum,
  33   lang_input_file_is_file_enum
  34 } lang_input_file_enum_type;
  35
  36 struct _fill_type
  37 {
  38   size_t size;
  39   unsigned char data[1];
  40 };
  41
  42 typedef struct statement_list
  43 {
  44   union lang_statement_union *  head;
  45   union lang_statement_union ** tail;
  46 } lang_statement_list_type;
  47
  48 typedef struct memory_region_name_struct
  49 {
  50   const char * name;
  51   struct memory_region_name_struct * next;
  52 } lang_memory_region_name;
  53
  54 typedef struct memory_region_struct
  55 {
  56   lang_memory_region_name name_list;
  57   struct memory_region_struct *next;
  58   union etree_union *origin_exp;
  59   bfd_vma origin;
  60   bfd_size_type length;
  61   union etree_union *length_exp;
  62   bfd_vma current;
  63   union lang_statement_union *last_os;
  64   flagword flags;
  65   flagword not_flags;
  66   bfd_boolean had_full_message;
  67 } lang_memory_region_type;
  68
  69 enum statement_enum
  70 {
  71   lang_address_statement_enum,
  72   lang_assignment_statement_enum,
  73   lang_data_statement_enum,
  74   lang_fill_statement_enum,
  75   lang_group_statement_enum,
  76   lang_input_section_enum,
  77   lang_input_statement_enum,
  78   lang_insert_statement_enum,
  79   lang_output_section_statement_enum,
  80   lang_output_statement_enum,
  81   lang_padding_statement_enum,
  82   lang_reloc_statement_enum,
  83   lang_target_statement_enum,
  84   lang_wild_statement_enum,
  85   lang_constructors_statement_enum,
  86   lang_object_symbols_statement_enum
  87 };
  88
  89 typedef struct lang_statement_header_struct
  90 {
  91   /* Next pointer for statement_list statement list.  */
  92   union lang_statement_union *next;
  93   enum statement_enum type;
  94 } lang_statement_header_type;
  95
  96 typedef struct
  97 {
  98   lang_statement_header_type header;
  99   union etree_union *exp;
 100 } lang_assignment_statement_type;
 101
 102 typedef struct lang_target_statement_struct
 103 {
 104   lang_statement_header_type header;
 105   const char *target;
 106 } lang_target_statement_type;
 107
 108 typedef struct lang_output_statement_struct
 109 {
 110   lang_statement_header_type header;
 111   const char *name;
 112 } lang_output_statement_type;
 113
 114 /* Section types specified in a linker script.  */
 115
 116 enum section_type
 117 {
 118   normal_section,
 119   first_overlay_section,
 120   overlay_section,
 121   noload_section,
 122   noalloc_section
 123 };
 124
 125 /* This structure holds a list of program headers describing
 126    segments in which this section should be placed.  */
 127
 128 typedef struct lang_output_section_phdr_list
 129 {
 130   struct lang_output_section_phdr_list *next;
 131   const char *name;
 132   bfd_boolean used;
 133 } lang_output_section_phdr_list;
 134
 135 typedef struct lang_output_section_statement_struct
 136 {
 137   lang_statement_header_type header;
 138   lang_statement_list_type children;
 139   struct lang_output_section_statement_struct *next;
 140   struct lang_output_section_statement_struct *prev;
 141   const char *name;
 142   asection *bfd_section;
 143   lang_memory_region_type *region;
 144   lang_memory_region_type *lma_region;
 145   fill_type *fill;
 146   union etree_union *addr_tree;
 147   union etree_union *load_base;
 148   union etree_union *section_alignment;
 149   union etree_union *subsection_alignment;
 150
 151   /* If non-null, an expression to evaluate after setting the section's
 152      size.  The expression is evaluated inside REGION (above) with '.'
 153      set to the end of the section.  Used in the last overlay section
 154      to move '.' past all the overlaid sections.  */
 155   union etree_union *update_dot_tree;
 156
 157   lang_output_section_phdr_list *phdrs;
 158
 159   unsigned int block_value;
 160   int constraint;
 161   flagword flags;
 162   enum section_type sectype;
 163   unsigned int processed_vma : 1;
 164   unsigned int processed_lma : 1;
 165   unsigned int all_input_readonly : 1;
 166   /* If this section should be ignored.  */
 167   unsigned int ignored : 1;
 168   /* If this section should update "dot".  Prevents section being ignored.  */
 169   unsigned int update_dot : 1;
 170   /* If this section is after assignment to _end.  */
 171   unsigned int after_end : 1;
 172   /* If this section uses the alignment of its input sections.  */
 173   unsigned int align_lma_with_input : 1;
 174 } lang_output_section_statement_type;
 175
 176 typedef struct
 177 {
 178   lang_statement_header_type header;
 179   fill_type *fill;
 180   int size;
 181   asection *output_section;
 182 } lang_fill_statement_type;
 183
 184 typedef struct
 185 {
 186   lang_statement_header_type header;
 187   unsigned int type;
 188   union etree_union *exp;
 189   bfd_vma value;
 190   asection *output_section;
 191   bfd_vma output_offset;
 192 } lang_data_statement_type;
 193
 194 /* Generate a reloc in the output file.  */
 195
 196 typedef struct
 197 {
 198   lang_statement_header_type header;
 199
 200   /* Reloc to generate.  */
 201   bfd_reloc_code_real_type reloc;
 202
 203   /* Reloc howto structure.  */
 204   reloc_howto_type *howto;
 205
 206   /* Section to generate reloc against.
 207      Exactly one of section and name must be NULL.  */
 208   asection *section;
 209
 210   /* Name of symbol to generate reloc against.
 211      Exactly one of section and name must be NULL.  */
 212   const char *name;
 213
 214   /* Expression for addend.  */
 215   union etree_union *addend_exp;
 216
 217   /* Resolved addend.  */
 218   bfd_vma addend_value;
 219
 220   /* Output section where reloc should be performed.  */
 221   asection *output_section;
 222
 223   /* Offset within output section.  */
 224   bfd_vma output_offset;
 225 } lang_reloc_statement_type;
 226
 227 struct lang_input_statement_flags
 228 {
 229   /* 1 means this file was specified in a -l option.  */
 230   unsigned int maybe_archive : 1;
 231
 232   /* 1 means this file was specified in a -l:namespec option.  */
 233   unsigned int full_name_provided : 1;
 234
 235   /* 1 means search a set of directories for this file.  */
 236   unsigned int search_dirs : 1;
 237
 238   /* 1 means this was found when processing a script in the sysroot.  */
 239   unsigned int sysrooted : 1;
 240
 241   /* 1 means this is base file of incremental load.
 242      Do not load this file's text or data.
 243      Also default text_start to after this file's bss.  */
 244   unsigned int just_syms : 1;
 245
 246   /* Whether to search for this entry as a dynamic archive.  */
 247   unsigned int dynamic : 1;
 248
 249   /* Set if a DT_NEEDED tag should be added not just for the dynamic library
 250      explicitly given by this entry but also for any dynamic libraries in
 251      this entry's needed list.  */
 252   unsigned int add_DT_NEEDED_for_dynamic : 1;
 253
 254   /* Set if this entry should cause a DT_NEEDED tag only when some
 255      regular file references its symbols (ie. --as-needed is in effect).  */
 256   unsigned int add_DT_NEEDED_for_regular : 1;
 257
 258   /* Whether to include the entire contents of an archive.  */
 259   unsigned int whole_archive : 1;
 260
 261   /* Set when bfd opening is successful.  */
 262   unsigned int loaded : 1;
 263
 264   unsigned int real : 1;
 265
 266   /* Set if the file does not exist.  */
 267   unsigned int missing_file : 1;
 268
 269   /* Set if reloading an archive or --as-needed lib.  */
 270   unsigned int reload : 1;
 271
 272 #ifdef ENABLE_PLUGINS
 273   /* Set if the file was claimed by a plugin.  */
 274   unsigned int claimed : 1;
 275
 276   /* Set if the file was claimed from an archive.  */
 277   unsigned int claim_archive : 1;
 278
 279   /* Set if added by the lto plugin add_input_file callback.  */
 280   unsigned int lto_output : 1;
 281 #endif /* ENABLE_PLUGINS */
 282
 283   /* Head of list of pushed flags.  */
 284   struct lang_input_statement_flags *pushed;
 285 };
 286
 287 typedef struct lang_input_statement_struct
 288 {
 289   lang_statement_header_type header;
 290   /* Name of this file.  */
 291   const char *filename;
 292   /* Name to use for the symbol giving address of text start.
 293      Usually the same as filename, but for a file spec'd with
 294      -l this is the -l switch itself rather than the filename.  */
 295   const char *local_sym_name;
 296   /* Extra search path. Used to find a file relative to the
 297      directory of the current linker script.  */
 298   const char *extra_search_path;
 299
 300   bfd *the_bfd;
 301
 302   ctf_archive_t *the_ctf;
 303
 304   struct flag_info *section_flag_list;
 305
 306   /* Next pointer for file_chain statement list.  */
 307   struct lang_input_statement_struct *next;
 308
 309   /* Next pointer for input_file_chain statement list.  */
 310   struct lang_input_statement_struct *next_real_file;
 311
 312   const char *target;
 313
 314   struct lang_input_statement_flags flags;
 315 } lang_input_statement_type;
 316
 317 typedef struct
 318 {
 319   lang_statement_header_type header;
 320   asection *section;
 321 } lang_input_section_type;
 322
 323 struct map_symbol_def {
 324   struct bfd_link_hash_entry *entry;
 325   struct map_symbol_def *next;
 326 };
 327
 328 /* For input sections, when writing a map file: head / tail of a linked
 329    list of hash table entries for symbols defined in this section.  */
 330 typedef struct input_section_userdata_struct
 331 {
 332   struct map_symbol_def *map_symbol_def_head;
 333   struct map_symbol_def **map_symbol_def_tail;
 334   unsigned long map_symbol_def_count;
 335 } input_section_userdata_type;
 336
 337 static inline bfd_boolean
 338 bfd_input_just_syms (const bfd *abfd)
 339 {
 340   lang_input_statement_type *is = bfd_usrdata (abfd);
 341   return is != NULL && is->flags.just_syms;
 342 }
 343
 344 typedef struct lang_wild_statement_struct lang_wild_statement_type;
 345
 346 typedef void (*callback_t) (lang_wild_statement_type *, struct wildcard_list *,
 347                             asection *, struct flag_info *,
 348                             lang_input_statement_type *, void *);
 349
 350 typedef void (*walk_wild_section_handler_t) (lang_wild_statement_type *,
 351                                              lang_input_statement_type *,
 352                                              callback_t callback,
 353                                              void *data);
 354
 355 typedef bfd_boolean (*lang_match_sec_type_func) (bfd *, const asection *,
 356                                                  bfd *, const asection *);
 357
 358 /* Binary search tree structure to efficiently sort sections by
 359    name.  */
 360 typedef struct lang_section_bst
 361 {
 362   asection *section;
 363   struct lang_section_bst *left;
 364   struct lang_section_bst *right;
 365 } lang_section_bst_type;
 366
 367 struct lang_wild_statement_struct
 368 {
 369   lang_statement_header_type header;
 370   const char *filename;
 371   bfd_boolean filenames_sorted;
 372   struct wildcard_list *section_list;
 373   bfd_boolean keep_sections;
 374   lang_statement_list_type children;
 375   struct name_list *exclude_name_list;
 376
 377   walk_wild_section_handler_t walk_wild_section_handler;
 378   struct wildcard_list *handler_data[4];
 379   lang_section_bst_type *tree;
 380   struct flag_info *section_flag_list;
 381 };
 382
 383 typedef struct lang_address_statement_struct
 384 {
 385   lang_statement_header_type header;
 386   const char *section_name;
 387   union etree_union *address;
 388   const segment_type *segment;
 389 } lang_address_statement_type;
 390
 391 typedef struct
 392 {
 393   lang_statement_header_type header;
 394   bfd_vma output_offset;
 395   bfd_size_type size;
 396   asection *output_section;
 397   fill_type *fill;
 398 } lang_padding_statement_type;
 399
 400 /* A group statement collects a set of libraries together.  The
 401    libraries are searched multiple times, until no new undefined
 402    symbols are found.  The effect is to search a group of libraries as
 403    though they were a single library.  */
 404
 405 typedef struct
 406 {
 407   lang_statement_header_type header;
 408   lang_statement_list_type children;
 409 } lang_group_statement_type;
 410
 411 typedef struct
 412 {
 413   lang_statement_header_type header;
 414   const char *where;
 415   bfd_boolean is_before;
 416 } lang_insert_statement_type;
 417
 418 typedef union lang_statement_union
 419 {
 420   lang_statement_header_type header;
 421   lang_address_statement_type address_statement;
 422   lang_assignment_statement_type assignment_statement;
 423   lang_data_statement_type data_statement;
 424   lang_fill_statement_type fill_statement;
 425   lang_group_statement_type group_statement;
 426   lang_input_section_type input_section;
 427   lang_input_statement_type input_statement;
 428   lang_insert_statement_type insert_statement;
 429   lang_output_section_statement_type output_section_statement;
 430   lang_output_statement_type output_statement;
 431   lang_padding_statement_type padding_statement;
 432   lang_reloc_statement_type reloc_statement;
 433   lang_target_statement_type target_statement;
 434   lang_wild_statement_type wild_statement;
 435 } lang_statement_union_type;
 436
 437 /* This structure holds information about a program header, from the
 438    PHDRS command in the linker script.  */
 439
 440 struct lang_phdr
 441 {
 442   struct lang_phdr *next;
 443   const char *name;
 444   unsigned long type;
 445   bfd_boolean filehdr;
 446   bfd_boolean phdrs;
 447   etree_type *at;
 448   etree_type *flags;
 449 };
 450
 451 /* This structure is used to hold a list of sections which may not
 452    cross reference each other.  */
 453
 454 typedef struct lang_nocrossref
 455 {
 456   struct lang_nocrossref *next;
 457   const char *name;
 458 } lang_nocrossref_type;
 459
 460 /* The list of nocrossref lists.  */
 461
 462 struct lang_nocrossrefs
 463 {
 464   struct lang_nocrossrefs *next;
 465   lang_nocrossref_type *list;
 466   bfd_boolean onlyfirst;
 467 };
 468
 469 /* This structure is used to hold a list of input section names which
 470    will not match an output section in the linker script.  */
 471
 472 struct unique_sections
 473 {
 474   struct unique_sections *next;
 475   const char *name;
 476 };
 477
 478 /* Used by place_orphan to keep track of orphan sections and statements.  */
 479
 480 struct orphan_save
 481 {
 482   const char *name;
 483   flagword flags;
 484   lang_output_section_statement_type *os;
 485   asection **section;
 486   lang_statement_union_type **stmt;
 487   lang_output_section_statement_type **os_tail;
 488 };
 489
 490 struct asneeded_minfo
 491 {
 492   struct asneeded_minfo *next;
 493   const char *soname;
 494   bfd *ref;
 495   const char *name;
 496 };
 497
 498 extern struct lang_phdr *lang_phdr_list;
 499 extern struct lang_nocrossrefs *nocrossref_list;
 500 extern const char *output_target;
 501 extern lang_output_section_statement_type *abs_output_section;
 502 extern lang_statement_list_type lang_os_list;
 503 extern struct lang_input_statement_flags input_flags;
 504 extern bfd_boolean lang_has_input_file;
 505 extern lang_statement_list_type *stat_ptr;
 506 extern bfd_boolean delete_output_file_on_failure;
 507
 508 extern struct bfd_sym_chain entry_symbol;
 509 extern const char *entry_section;
 510 extern bfd_boolean entry_from_cmdline;
 511 extern lang_statement_list_type file_chain;
 512 extern lang_statement_list_type input_file_chain;
 513
 514 extern int lang_statement_iteration;
 515 extern struct asneeded_minfo **asneeded_list_tail;
 516
 517 extern void (*output_bfd_hash_table_free_fn) (struct bfd_link_hash_table *);
 518
 519 extern void lang_init
 520   (void);
 521 extern void lang_finish
 522   (void);
 523 extern lang_memory_region_type * lang_memory_region_lookup
 524   (const char * const, bfd_boolean);
 525 extern void lang_memory_region_alias
 526   (const char *, const char *);
 527 extern void lang_map
 528   (void);
 529 extern void lang_set_flags
 530   (lang_memory_region_type *, const char *, int);
 531 extern void lang_add_output
 532   (const char *, int from_script);
 533 extern lang_output_section_statement_type *lang_enter_output_section_statement
 534   (const char *, etree_type *, enum section_type, etree_type *, etree_type *,
 535    etree_type *, int, int);
 536 extern void lang_final
 537   (void);
 538 extern void lang_relax_sections
 539   (bfd_boolean);
 540 extern void lang_process
 541   (void);
 542 extern void lang_section_start
 543   (const char *, union etree_union *, const segment_type *);
 544 extern void lang_add_entry
 545   (const char *, bfd_boolean);
 546 extern void lang_default_entry
 547   (const char *);
 548 extern void lang_add_target
 549   (const char *);
 550 extern void lang_add_wild
 551   (struct wildcard_spec *, struct wildcard_list *, bfd_boolean);
 552 extern void lang_add_map
 553   (const char *);
 554 extern void lang_add_fill
 555   (fill_type *);
 556 extern lang_assignment_statement_type *lang_add_assignment
 557   (union etree_union *);
 558 extern void lang_add_attribute
 559   (enum statement_enum);
 560 extern void lang_startup
 561   (const char *);
 562 extern void lang_float
 563   (bfd_boolean);
 564 extern void lang_leave_output_section_statement
 565   (fill_type *, const char *, lang_output_section_phdr_list *,
 566    const char *);
 567 extern void lang_for_each_input_file
 568   (void (*dothis) (lang_input_statement_type *));
 569 extern void lang_for_each_file
 570   (void (*dothis) (lang_input_statement_type *));
 571 extern void lang_reset_memory_regions
 572   (void);
 573 extern void lang_do_assignments
 574   (lang_phase_type);
 575 extern asection *section_for_dot
 576   (void);
 577
 578 #define LANG_FOR_EACH_INPUT_STATEMENT(statement)                        \
 579   lang_input_statement_type *statement;                                 \
 580   for (statement = (lang_input_statement_type *) file_chain.head;       \
 581        statement != NULL;                                               \
 582        statement = statement->next)
 583
 584 #define lang_output_section_find(NAME) \
 585   lang_output_section_statement_lookup (NAME, 0, FALSE)
 586
 587 extern void lang_process
 588   (void);
 589 extern void ldlang_add_file
 590   (lang_input_statement_type *);
 591 extern lang_output_section_statement_type *lang_output_section_find_by_flags
 592   (const asection *, flagword, lang_output_section_statement_type **,
 593    lang_match_sec_type_func);
 594 extern lang_output_section_statement_type *lang_insert_orphan
 595   (asection *, const char *, int, lang_output_section_statement_type *,
 596    struct orphan_save *, etree_type *, lang_statement_list_type *);
 597 extern lang_input_statement_type *lang_add_input_file
 598   (const char *, lang_input_file_enum_type, const char *);
 599 extern void lang_add_keepsyms_file
 600   (const char *);
 601 extern lang_output_section_statement_type *lang_output_section_get
 602   (const asection *);
 603 extern lang_output_section_statement_type *lang_output_section_statement_lookup
 604   (const char *, int, bfd_boolean);
 605 extern lang_output_section_statement_type *next_matching_output_section_statement
 606   (lang_output_section_statement_type *, int);
 607 extern void ldlang_add_undef
 608   (const char *const, bfd_boolean);
 609 extern void ldlang_add_require_defined
 610   (const char *const);
 611 extern void lang_add_output_format
 612   (const char *, const char *, const char *, int);
 613 extern void lang_list_init
 614   (lang_statement_list_type *);
 615 extern void push_stat_ptr
 616   (lang_statement_list_type *);
 617 extern void pop_stat_ptr
 618   (void);
 619 extern void lang_add_data
 620   (int type, union etree_union *);
 621 extern void lang_add_reloc
 622   (bfd_reloc_code_real_type, reloc_howto_type *, asection *, const char *,
 623    union etree_union *);
 624 extern void lang_for_each_statement
 625   (void (*) (lang_statement_union_type *));
 626 extern void lang_for_each_statement_worker
 627   (void (*) (lang_statement_union_type *), lang_statement_union_type *);
 628 extern void *stat_alloc
 629   (size_t);
 630 extern void strip_excluded_output_sections
 631   (void);
 632 extern void lang_clear_os_map
 633   (void);
 634 extern void dprint_statement
 635   (lang_statement_union_type *, int);
 636 extern void lang_size_sections
 637   (bfd_boolean *, bfd_boolean);
 638 extern void one_lang_size_sections_pass
 639   (bfd_boolean *, bfd_boolean);
 640 extern void lang_add_insert
 641   (const char *, int);
 642 extern void lang_enter_group
 643   (void);
 644 extern void lang_leave_group
 645   (void);
 646 extern void lang_add_section
 647   (lang_statement_list_type *, asection *,
 648    struct flag_info *, lang_output_section_statement_type *);
 649 extern void lang_new_phdr
 650   (const char *, etree_type *, bfd_boolean, bfd_boolean, etree_type *,
 651    etree_type *);
 652 extern void lang_add_nocrossref
 653   (lang_nocrossref_type *);
 654 extern void lang_add_nocrossref_to
 655   (lang_nocrossref_type *);
 656 extern void lang_enter_overlay
 657   (etree_type *, etree_type *);
 658 extern void lang_enter_overlay_section
 659   (const char *);
 660 extern void lang_leave_overlay_section
 661   (fill_type *, lang_output_section_phdr_list *);
 662 extern void lang_leave_overlay
 663   (etree_type *, int, fill_type *, const char *,
 664    lang_output_section_phdr_list *, const char *);
 665
 666 extern struct bfd_elf_version_expr *lang_new_vers_pattern
 667   (struct bfd_elf_version_expr *, const char *, const char *, bfd_boolean);
 668 extern struct bfd_elf_version_tree *lang_new_vers_node
 669   (struct bfd_elf_version_expr *, struct bfd_elf_version_expr *);
 670 extern struct bfd_elf_version_deps *lang_add_vers_depend
 671   (struct bfd_elf_version_deps *, const char *);
 672 extern void lang_register_vers_node
 673   (const char *, struct bfd_elf_version_tree *, struct bfd_elf_version_deps *);
 674 extern void lang_append_dynamic_list (struct bfd_elf_version_expr *);
 675 extern void lang_append_dynamic_list_cpp_typeinfo (void);
 676 extern void lang_append_dynamic_list_cpp_new (void);
 677 extern void lang_add_unique
 678   (const char *);
 679 extern const char *lang_get_output_target
 680   (void);
 681 extern void add_excluded_libs (const char *);
 682 extern bfd_boolean load_symbols
 683   (lang_input_statement_type *, lang_statement_list_type *);
 684
 685 struct elf_sym_strtab;
 686 struct elf_strtab_hash;
 687 extern void ldlang_ctf_apply_strsym
 688   (struct elf_sym_strtab *, bfd_size_type, struct elf_strtab_hash *);
 689 extern void ldlang_write_ctf_late
 690   (void);
 691 extern bfd_boolean
 692 ldlang_override_segment_assignment
 693   (struct bfd_link_info *, bfd *, asection *, asection *, bfd_boolean);
 694
 695 extern void
 696 lang_ld_feature (char *);
 697
 698 extern void
 699 lang_print_memory_usage (void);
 700
 701 extern void
 702 lang_add_gc_name (const char *);
 703
 704 #endif