ld/ldlang.h

   1 /* ldlang.h - linker command language support
   2    Copyright (C) 1991-2019 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
 297   bfd *the_bfd;
 298
 299   ctf_archive_t *the_ctf;
 300
 301   struct flag_info *section_flag_list;
 302
 303   /* Next pointer for file_chain statement list.  */
 304   struct lang_input_statement_struct *next;
 305
 306   /* Next pointer for input_file_chain statement list.  */
 307   struct lang_input_statement_struct *next_real_file;
 308
 309   const char *target;
 310
 311   struct lang_input_statement_flags flags;
 312 } lang_input_statement_type;
 313
 314 typedef struct
 315 {
 316   lang_statement_header_type header;
 317   asection *section;
 318 } lang_input_section_type;
 319
 320 struct map_symbol_def {
 321   struct bfd_link_hash_entry *entry;
 322   struct map_symbol_def *next;
 323 };
 324
 325 /* For input sections, when writing a map file: head / tail of a linked
 326    list of hash table entries for symbols defined in this section.  */
 327 typedef struct input_section_userdata_struct
 328 {
 329   struct map_symbol_def *map_symbol_def_head;
 330   struct map_symbol_def **map_symbol_def_tail;
 331   unsigned long map_symbol_def_count;
 332 } input_section_userdata_type;
 333
 334 static inline bfd_boolean
 335 bfd_input_just_syms (const bfd *abfd)
 336 {
 337   lang_input_statement_type *is = bfd_usrdata (abfd);
 338   return is != NULL && is->flags.just_syms;
 339 }
 340
 341 typedef struct lang_wild_statement_struct lang_wild_statement_type;
 342
 343 typedef void (*callback_t) (lang_wild_statement_type *, struct wildcard_list *,
 344                             asection *, struct flag_info *,
 345                             lang_input_statement_type *, void *);
 346
 347 typedef void (*walk_wild_section_handler_t) (lang_wild_statement_type *,
 348                                              lang_input_statement_type *,
 349                                              callback_t callback,
 350                                              void *data);
 351
 352 typedef bfd_boolean (*lang_match_sec_type_func) (bfd *, const asection *,
 353                                                  bfd *, const asection *);
 354
 355 /* Binary search tree structure to efficiently sort sections by
 356    name.  */
 357 typedef struct lang_section_bst
 358 {
 359   asection *section;
 360   struct lang_section_bst *left;
 361   struct lang_section_bst *right;
 362 } lang_section_bst_type;
 363
 364 struct lang_wild_statement_struct
 365 {
 366   lang_statement_header_type header;
 367   const char *filename;
 368   bfd_boolean filenames_sorted;
 369   struct wildcard_list *section_list;
 370   bfd_boolean keep_sections;
 371   lang_statement_list_type children;
 372   struct name_list *exclude_name_list;
 373
 374   walk_wild_section_handler_t walk_wild_section_handler;
 375   struct wildcard_list *handler_data[4];
 376   lang_section_bst_type *tree;
 377   struct flag_info *section_flag_list;
 378 };
 379
 380 typedef struct lang_address_statement_struct
 381 {
 382   lang_statement_header_type header;
 383   const char *section_name;
 384   union etree_union *address;
 385   const segment_type *segment;
 386 } lang_address_statement_type;
 387
 388 typedef struct
 389 {
 390   lang_statement_header_type header;
 391   bfd_vma output_offset;
 392   bfd_size_type size;
 393   asection *output_section;
 394   fill_type *fill;
 395 } lang_padding_statement_type;
 396
 397 /* A group statement collects a set of libraries together.  The
 398    libraries are searched multiple times, until no new undefined
 399    symbols are found.  The effect is to search a group of libraries as
 400    though they were a single library.  */
 401
 402 typedef struct
 403 {
 404   lang_statement_header_type header;
 405   lang_statement_list_type children;
 406 } lang_group_statement_type;
 407
 408 typedef struct
 409 {
 410   lang_statement_header_type header;
 411   const char *where;
 412   bfd_boolean is_before;
 413 } lang_insert_statement_type;
 414
 415 typedef union lang_statement_union
 416 {
 417   lang_statement_header_type header;
 418   lang_address_statement_type address_statement;
 419   lang_assignment_statement_type assignment_statement;
 420   lang_data_statement_type data_statement;
 421   lang_fill_statement_type fill_statement;
 422   lang_group_statement_type group_statement;
 423   lang_input_section_type input_section;
 424   lang_input_statement_type input_statement;
 425   lang_insert_statement_type insert_statement;
 426   lang_output_section_statement_type output_section_statement;
 427   lang_output_statement_type output_statement;
 428   lang_padding_statement_type padding_statement;
 429   lang_reloc_statement_type reloc_statement;
 430   lang_target_statement_type target_statement;
 431   lang_wild_statement_type wild_statement;
 432 } lang_statement_union_type;
 433
 434 /* This structure holds information about a program header, from the
 435    PHDRS command in the linker script.  */
 436
 437 struct lang_phdr
 438 {
 439   struct lang_phdr *next;
 440   const char *name;
 441   unsigned long type;
 442   bfd_boolean filehdr;
 443   bfd_boolean phdrs;
 444   etree_type *at;
 445   etree_type *flags;
 446 };
 447
 448 /* This structure is used to hold a list of sections which may not
 449    cross reference each other.  */
 450
 451 typedef struct lang_nocrossref
 452 {
 453   struct lang_nocrossref *next;
 454   const char *name;
 455 } lang_nocrossref_type;
 456
 457 /* The list of nocrossref lists.  */
 458
 459 struct lang_nocrossrefs
 460 {
 461   struct lang_nocrossrefs *next;
 462   lang_nocrossref_type *list;
 463   bfd_boolean onlyfirst;
 464 };
 465
 466 /* This structure is used to hold a list of input section names which
 467    will not match an output section in the linker script.  */
 468
 469 struct unique_sections
 470 {
 471   struct unique_sections *next;
 472   const char *name;
 473 };
 474
 475 /* Used by place_orphan to keep track of orphan sections and statements.  */
 476
 477 struct orphan_save
 478 {
 479   const char *name;
 480   flagword flags;
 481   lang_output_section_statement_type *os;
 482   asection **section;
 483   lang_statement_union_type **stmt;
 484   lang_output_section_statement_type **os_tail;
 485 };
 486
 487 struct asneeded_minfo
 488 {
 489   struct asneeded_minfo *next;
 490   const char *soname;
 491   bfd *ref;
 492   const char *name;
 493 };
 494
 495 extern struct lang_phdr *lang_phdr_list;
 496 extern struct lang_nocrossrefs *nocrossref_list;
 497 extern const char *output_target;
 498 extern lang_output_section_statement_type *abs_output_section;
 499 extern lang_statement_list_type lang_os_list;
 500 extern struct lang_input_statement_flags input_flags;
 501 extern bfd_boolean lang_has_input_file;
 502 extern lang_statement_list_type *stat_ptr;
 503 extern bfd_boolean delete_output_file_on_failure;
 504
 505 extern struct bfd_sym_chain entry_symbol;
 506 extern const char *entry_section;
 507 extern bfd_boolean entry_from_cmdline;
 508 extern lang_statement_list_type file_chain;
 509 extern lang_statement_list_type input_file_chain;
 510
 511 extern int lang_statement_iteration;
 512 extern struct asneeded_minfo **asneeded_list_tail;
 513
 514 extern void (*output_bfd_hash_table_free_fn) (struct bfd_link_hash_table *);
 515
 516 extern void lang_init
 517   (void);
 518 extern void lang_finish
 519   (void);
 520 extern lang_memory_region_type * lang_memory_region_lookup
 521   (const char * const, bfd_boolean);
 522 extern void lang_memory_region_alias
 523   (const char *, const char *);
 524 extern void lang_map
 525   (void);
 526 extern void lang_set_flags
 527   (lang_memory_region_type *, const char *, int);
 528 extern void lang_add_output
 529   (const char *, int from_script);
 530 extern lang_output_section_statement_type *lang_enter_output_section_statement
 531   (const char *, etree_type *, enum section_type, etree_type *, etree_type *,
 532    etree_type *, int, int);
 533 extern void lang_final
 534   (void);
 535 extern void lang_relax_sections
 536   (bfd_boolean);
 537 extern void lang_process
 538   (void);
 539 extern void lang_section_start
 540   (const char *, union etree_union *, const segment_type *);
 541 extern void lang_add_entry
 542   (const char *, bfd_boolean);
 543 extern void lang_default_entry
 544   (const char *);
 545 extern void lang_add_target
 546   (const char *);
 547 extern void lang_add_wild
 548   (struct wildcard_spec *, struct wildcard_list *, bfd_boolean);
 549 extern void lang_add_map
 550   (const char *);
 551 extern void lang_add_fill
 552   (fill_type *);
 553 extern lang_assignment_statement_type *lang_add_assignment
 554   (union etree_union *);
 555 extern void lang_add_attribute
 556   (enum statement_enum);
 557 extern void lang_startup
 558   (const char *);
 559 extern void lang_float
 560   (bfd_boolean);
 561 extern void lang_leave_output_section_statement
 562   (fill_type *, const char *, lang_output_section_phdr_list *,
 563    const char *);
 564 extern void lang_for_each_input_file
 565   (void (*dothis) (lang_input_statement_type *));
 566 extern void lang_for_each_file
 567   (void (*dothis) (lang_input_statement_type *));
 568 extern void lang_reset_memory_regions
 569   (void);
 570 extern void lang_do_assignments
 571   (lang_phase_type);
 572 extern asection *section_for_dot
 573   (void);
 574
 575 #define LANG_FOR_EACH_INPUT_STATEMENT(statement)                        \
 576   lang_input_statement_type *statement;                                 \
 577   for (statement = (lang_input_statement_type *) file_chain.head;       \
 578        statement != NULL;                                               \
 579        statement = statement->next)
 580
 581 #define lang_output_section_find(NAME) \
 582   lang_output_section_statement_lookup (NAME, 0, FALSE)
 583
 584 extern void lang_process
 585   (void);
 586 extern void ldlang_add_file
 587   (lang_input_statement_type *);
 588 extern lang_output_section_statement_type *lang_output_section_find_by_flags
 589   (const asection *, flagword, lang_output_section_statement_type **,
 590    lang_match_sec_type_func);
 591 extern lang_output_section_statement_type *lang_insert_orphan
 592   (asection *, const char *, int, lang_output_section_statement_type *,
 593    struct orphan_save *, etree_type *, lang_statement_list_type *);
 594 extern lang_input_statement_type *lang_add_input_file
 595   (const char *, lang_input_file_enum_type, const char *);
 596 extern void lang_add_keepsyms_file
 597   (const char *);
 598 extern lang_output_section_statement_type *lang_output_section_get
 599   (const asection *);
 600 extern lang_output_section_statement_type *lang_output_section_statement_lookup
 601   (const char *, int, bfd_boolean);
 602 extern lang_output_section_statement_type *next_matching_output_section_statement
 603   (lang_output_section_statement_type *, int);
 604 extern void ldlang_add_undef
 605   (const char *const, bfd_boolean);
 606 extern void ldlang_add_require_defined
 607   (const char *const);
 608 extern void lang_add_output_format
 609   (const char *, const char *, const char *, int);
 610 extern void lang_list_init
 611   (lang_statement_list_type *);
 612 extern void push_stat_ptr
 613   (lang_statement_list_type *);
 614 extern void pop_stat_ptr
 615   (void);
 616 extern void lang_add_data
 617   (int type, union etree_union *);
 618 extern void lang_add_reloc
 619   (bfd_reloc_code_real_type, reloc_howto_type *, asection *, const char *,
 620    union etree_union *);
 621 extern void lang_for_each_statement
 622   (void (*) (lang_statement_union_type *));
 623 extern void lang_for_each_statement_worker
 624   (void (*) (lang_statement_union_type *), lang_statement_union_type *);
 625 extern void *stat_alloc
 626   (size_t);
 627 extern void strip_excluded_output_sections
 628   (void);
 629 extern void lang_clear_os_map
 630   (void);
 631 extern void dprint_statement
 632   (lang_statement_union_type *, int);
 633 extern void lang_size_sections
 634   (bfd_boolean *, bfd_boolean);
 635 extern void one_lang_size_sections_pass
 636   (bfd_boolean *, bfd_boolean);
 637 extern void lang_add_insert
 638   (const char *, int);
 639 extern void lang_enter_group
 640   (void);
 641 extern void lang_leave_group
 642   (void);
 643 extern void lang_add_section
 644   (lang_statement_list_type *, asection *,
 645    struct flag_info *, lang_output_section_statement_type *);
 646 extern void lang_new_phdr
 647   (const char *, etree_type *, bfd_boolean, bfd_boolean, etree_type *,
 648    etree_type *);
 649 extern void lang_add_nocrossref
 650   (lang_nocrossref_type *);
 651 extern void lang_add_nocrossref_to
 652   (lang_nocrossref_type *);
 653 extern void lang_enter_overlay
 654   (etree_type *, etree_type *);
 655 extern void lang_enter_overlay_section
 656   (const char *);
 657 extern void lang_leave_overlay_section
 658   (fill_type *, lang_output_section_phdr_list *);
 659 extern void lang_leave_overlay
 660   (etree_type *, int, fill_type *, const char *,
 661    lang_output_section_phdr_list *, const char *);
 662
 663 extern struct bfd_elf_version_expr *lang_new_vers_pattern
 664   (struct bfd_elf_version_expr *, const char *, const char *, bfd_boolean);
 665 extern struct bfd_elf_version_tree *lang_new_vers_node
 666   (struct bfd_elf_version_expr *, struct bfd_elf_version_expr *);
 667 extern struct bfd_elf_version_deps *lang_add_vers_depend
 668   (struct bfd_elf_version_deps *, const char *);
 669 extern void lang_register_vers_node
 670   (const char *, struct bfd_elf_version_tree *, struct bfd_elf_version_deps *);
 671 extern void lang_append_dynamic_list (struct bfd_elf_version_expr *);
 672 extern void lang_append_dynamic_list_cpp_typeinfo (void);
 673 extern void lang_append_dynamic_list_cpp_new (void);
 674 extern void lang_add_unique
 675   (const char *);
 676 extern const char *lang_get_output_target
 677   (void);
 678 extern void add_excluded_libs (const char *);
 679 extern bfd_boolean load_symbols
 680   (lang_input_statement_type *, lang_statement_list_type *);
 681
 682 struct elf_sym_strtab;
 683 struct elf_strtab_hash;
 684 extern void ldlang_ctf_apply_strsym
 685   (struct elf_sym_strtab *, bfd_size_type, struct elf_strtab_hash *);
 686 extern void ldlang_write_ctf_late
 687   (void);
 688 extern bfd_boolean
 689 ldlang_override_segment_assignment
 690   (struct bfd_link_info *, bfd *, asection *, asection *, bfd_boolean);
 691
 692 extern void
 693 lang_ld_feature (char *);
 694
 695 extern void
 696 lang_print_memory_usage (void);
 697
 698 extern void
 699 lang_add_gc_name (const char *);
 700
 701 #endif