1 /* bfdlink.h -- header file for BFD link routines 2 Copyright (C) 1993-2015 Free Software Foundation, Inc. 3 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support. 4 5 This file is part of BFD, the Binary File Descriptor library. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 20 MA 02110-1301, USA. */ 21 22 #ifndef BFDLINK_H 23 #define BFDLINK_H 24 25 /* Which symbols to strip during a link. */ 26 enum bfd_link_strip 27 { 28 strip_none, /* Don't strip any symbols. */ 29 strip_debugger, /* Strip debugging symbols. */ 30 strip_some, /* keep_hash is the list of symbols to keep. */ 31 strip_all /* Strip all symbols. */ 32 }; 33 34 /* Which local symbols to discard during a link. This is irrelevant 35 if strip_all is used. */ 36 enum bfd_link_discard 37 { 38 discard_sec_merge, /* Discard local temporary symbols in SEC_MERGE 39 sections. */ 40 discard_none, /* Don't discard any locals. */ 41 discard_l, /* Discard local temporary symbols. */ 42 discard_all /* Discard all locals. */ 43 }; 44 45 /* Describes the type of hash table entry structure being used. 46 Different hash table structure have different fields and so 47 support different linking features. */ 48 enum bfd_link_hash_table_type 49 { 50 bfd_link_generic_hash_table, 51 bfd_link_elf_hash_table 52 }; 53 54 /* These are the possible types of an entry in the BFD link hash 55 table. */ 56 57 enum bfd_link_hash_type 58 { 59 bfd_link_hash_new, /* Symbol is new. */ 60 bfd_link_hash_undefined, /* Symbol seen before, but undefined. */ 61 bfd_link_hash_undefweak, /* Symbol is weak and undefined. */ 62 bfd_link_hash_defined, /* Symbol is defined. */ 63 bfd_link_hash_defweak, /* Symbol is weak and defined. */ 64 bfd_link_hash_common, /* Symbol is common. */ 65 bfd_link_hash_indirect, /* Symbol is an indirect link. */ 66 bfd_link_hash_warning /* Like indirect, but warn if referenced. */ 67 }; 68 69 enum bfd_link_common_skip_ar_symbols 70 { 71 bfd_link_common_skip_none, 72 bfd_link_common_skip_text, 73 bfd_link_common_skip_data, 74 bfd_link_common_skip_all 75 }; 76 77 struct bfd_link_hash_common_entry 78 { 79 unsigned int alignment_power; /* Alignment. */ 80 asection *section; /* Symbol section. */ 81 }; 82 83 /* The linking routines use a hash table which uses this structure for 84 its elements. */ 85 86 struct bfd_link_hash_entry 87 { 88 /* Base hash table entry structure. */ 89 struct bfd_hash_entry root; 90 91 /* Type of this entry. */ 92 ENUM_BITFIELD (bfd_link_hash_type) type : 8; 93 94 /* Symbol is referenced in a normal object file, as distict from a LTO 95 IR object file. */ 96 unsigned int non_ir_ref : 1; 97 98 /* Symbol is a built-in define. These will be overridden by PROVIDE 99 in a linker script. */ 100 unsigned int linker_def : 1; 101 102 /* A union of information depending upon the type. */ 103 union 104 { 105 /* Nothing is kept for bfd_hash_new. */ 106 /* bfd_link_hash_undefined, bfd_link_hash_undefweak. */ 107 struct 108 { 109 /* Undefined and common symbols are kept in a linked list through 110 this field. This field is present in all of the union element 111 so that we don't need to remove entries from the list when we 112 change their type. Removing entries would either require the 113 list to be doubly linked, which would waste more memory, or 114 require a traversal. When an undefined or common symbol is 115 created, it should be added to this list, the head of which is in 116 the link hash table itself. As symbols are defined, they need 117 not be removed from the list; anything which reads the list must 118 doublecheck the symbol type. 119 120 Weak symbols are not kept on this list. 121 122 Defined and defweak symbols use this field as a reference marker. 123 If the field is not NULL, or this structure is the tail of the 124 undefined symbol list, the symbol has been referenced. If the 125 symbol is undefined and becomes defined, this field will 126 automatically be non-NULL since the symbol will have been on the 127 undefined symbol list. */ 128 struct bfd_link_hash_entry *next; 129 bfd *abfd; /* BFD symbol was found in. */ 130 } undef; 131 /* bfd_link_hash_defined, bfd_link_hash_defweak. */ 132 struct 133 { 134 struct bfd_link_hash_entry *next; 135 asection *section; /* Symbol section. */ 136 bfd_vma value; /* Symbol value. */ 137 } def; 138 /* bfd_link_hash_indirect, bfd_link_hash_warning. */ 139 struct 140 { 141 struct bfd_link_hash_entry *next; 142 struct bfd_link_hash_entry *link; /* Real symbol. */ 143 const char *warning; /* Warning (bfd_link_hash_warning only). */ 144 } i; 145 /* bfd_link_hash_common. */ 146 struct 147 { 148 struct bfd_link_hash_entry *next; 149 /* The linker needs to know three things about common 150 symbols: the size, the alignment, and the section in 151 which the symbol should be placed. We store the size 152 here, and we allocate a small structure to hold the 153 section and the alignment. The alignment is stored as a 154 power of two. We don't store all the information 155 directly because we don't want to increase the size of 156 the union; this structure is a major space user in the 157 linker. */ 158 struct bfd_link_hash_common_entry *p; 159 bfd_size_type size; /* Common symbol size. */ 160 } c; 161 } u; 162 }; 163 164 /* This is the link hash table. It is a derived class of 165 bfd_hash_table. */ 166 167 struct bfd_link_hash_table 168 { 169 /* The hash table itself. */ 170 struct bfd_hash_table table; 171 /* A linked list of undefined and common symbols, linked through the 172 next field in the bfd_link_hash_entry structure. */ 173 struct bfd_link_hash_entry *undefs; 174 /* Entries are added to the tail of the undefs list. */ 175 struct bfd_link_hash_entry *undefs_tail; 176 /* Function to free the hash table on closing BFD. */ 177 void (*hash_table_free) (bfd *); 178 /* The type of the link hash table. */ 179 enum bfd_link_hash_table_type type; 180 }; 181 182 /* Look up an entry in a link hash table. If FOLLOW is TRUE, this 183 follows bfd_link_hash_indirect and bfd_link_hash_warning links to 184 the real symbol. */ 185 extern struct bfd_link_hash_entry *bfd_link_hash_lookup 186 (struct bfd_link_hash_table *, const char *, bfd_boolean create, 187 bfd_boolean copy, bfd_boolean follow); 188 189 /* Look up an entry in the main linker hash table if the symbol might 190 be wrapped. This should only be used for references to an 191 undefined symbol, not for definitions of a symbol. */ 192 193 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup 194 (bfd *, struct bfd_link_info *, const char *, bfd_boolean, 195 bfd_boolean, bfd_boolean); 196 197 /* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_" 198 and the remainder is found in wrap_hash, return the real symbol. */ 199 200 extern struct bfd_link_hash_entry *unwrap_hash_lookup 201 (struct bfd_link_info *, bfd *, struct bfd_link_hash_entry *); 202 203 /* Traverse a link hash table. */ 204 extern void bfd_link_hash_traverse 205 (struct bfd_link_hash_table *, 206 bfd_boolean (*) (struct bfd_link_hash_entry *, void *), 207 void *); 208 209 /* Add an entry to the undefs list. */ 210 extern void bfd_link_add_undef 211 (struct bfd_link_hash_table *, struct bfd_link_hash_entry *); 212 213 /* Remove symbols from the undefs list that don't belong there. */ 214 extern void bfd_link_repair_undef_list 215 (struct bfd_link_hash_table *table); 216 217 /* Read symbols and cache symbol pointer array in outsymbols. */ 218 extern bfd_boolean bfd_generic_link_read_symbols (bfd *); 219 220 struct bfd_sym_chain 221 { 222 struct bfd_sym_chain *next; 223 const char *name; 224 }; 225 226 /* How to handle unresolved symbols. 227 There are four possibilities which are enumerated below: */ 228 enum report_method 229 { 230 /* This is the initial value when then link_info structure is created. 231 It allows the various stages of the linker to determine whether they 232 allowed to set the value. */ 233 RM_NOT_YET_SET = 0, 234 RM_IGNORE, 235 RM_GENERATE_WARNING, 236 RM_GENERATE_ERROR 237 }; 238 239 typedef enum {with_flags, without_flags} flag_type; 240 241 /* A section flag list. */ 242 struct flag_info_list 243 { 244 flag_type with; 245 const char *name; 246 bfd_boolean valid; 247 struct flag_info_list *next; 248 }; 249 250 /* Section flag info. */ 251 struct flag_info 252 { 253 flagword only_with_flags; 254 flagword not_with_flags; 255 struct flag_info_list *flag_list; 256 bfd_boolean flags_initialized; 257 }; 258 259 struct bfd_elf_dynamic_list; 260 struct bfd_elf_version_tree; 261 262 /* This structure holds all the information needed to communicate 263 between BFD and the linker when doing a link. */ 264 265 struct bfd_link_info 266 { 267 /* TRUE if BFD should generate a shared object (or a pie). */ 268 unsigned int shared: 1; 269 270 /* TRUE if generating an executable, position independent or not. */ 271 unsigned int executable : 1; 272 273 /* TRUE if generating a position independent executable. */ 274 unsigned int pie: 1; 275 276 /* TRUE if BFD should generate a relocatable object file. */ 277 unsigned int relocatable: 1; 278 279 /* TRUE if BFD should pre-bind symbols in a shared object. */ 280 unsigned int symbolic: 1; 281 282 /* TRUE if executable should not contain copy relocs. 283 Setting this true may result in a non-sharable text segment. */ 284 unsigned int nocopyreloc: 1; 285 286 /* TRUE if BFD should export all symbols in the dynamic symbol table 287 of an executable, rather than only those used. */ 288 unsigned int export_dynamic: 1; 289 290 /* TRUE if a default symbol version should be created and used for 291 exported symbols. */ 292 unsigned int create_default_symver: 1; 293 294 /* TRUE if unreferenced sections should be removed. */ 295 unsigned int gc_sections: 1; 296 297 /* TRUE if every symbol should be reported back via the notice 298 callback. */ 299 unsigned int notice_all: 1; 300 301 /* TRUE if the LTO plugin is active. */ 302 unsigned int lto_plugin_active: 1; 303 304 /* TRUE if we are loading LTO outputs. */ 305 unsigned int loading_lto_outputs: 1; 306 307 /* TRUE if global symbols in discarded sections should be stripped. */ 308 unsigned int strip_discarded: 1; 309 310 /* TRUE if all data symbols should be dynamic. */ 311 unsigned int dynamic_data: 1; 312 313 /* Which symbols to strip. */ 314 ENUM_BITFIELD (bfd_link_strip) strip : 2; 315 316 /* Which local symbols to discard. */ 317 ENUM_BITFIELD (bfd_link_discard) discard : 2; 318 319 /* Criteria for skipping symbols when determining 320 whether to include an object from an archive. */ 321 ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2; 322 323 /* What to do with unresolved symbols in an object file. 324 When producing executables the default is GENERATE_ERROR. 325 When producing shared libraries the default is IGNORE. The 326 assumption with shared libraries is that the reference will be 327 resolved at load/execution time. */ 328 ENUM_BITFIELD (report_method) unresolved_syms_in_objects : 2; 329 330 /* What to do with unresolved symbols in a shared library. 331 The same defaults apply. */ 332 ENUM_BITFIELD (report_method) unresolved_syms_in_shared_libs : 2; 333 334 /* TRUE if shared objects should be linked directly, not shared. */ 335 unsigned int static_link: 1; 336 337 /* TRUE if symbols should be retained in memory, FALSE if they 338 should be freed and reread. */ 339 unsigned int keep_memory: 1; 340 341 /* TRUE if BFD should generate relocation information in the final 342 executable. */ 343 unsigned int emitrelocations: 1; 344 345 /* TRUE if PT_GNU_RELRO segment should be created. */ 346 unsigned int relro: 1; 347 348 /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment 349 should be created. */ 350 unsigned int eh_frame_hdr: 1; 351 352 /* TRUE if we should warn when adding a DT_TEXTREL to a shared object. */ 353 unsigned int warn_shared_textrel: 1; 354 355 /* TRUE if we should error when adding a DT_TEXTREL. */ 356 unsigned int error_textrel: 1; 357 358 /* TRUE if .hash section should be created. */ 359 unsigned int emit_hash: 1; 360 361 /* TRUE if .gnu.hash section should be created. */ 362 unsigned int emit_gnu_hash: 1; 363 364 /* If TRUE reduce memory overheads, at the expense of speed. This will 365 cause map file generation to use an O(N^2) algorithm and disable 366 caching ELF symbol buffer. */ 367 unsigned int reduce_memory_overheads: 1; 368 369 /* TRUE if the output file should be in a traditional format. This 370 is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag 371 on the output file, but may be checked when reading the input 372 files. */ 373 unsigned int traditional_format: 1; 374 375 /* TRUE if non-PLT relocs should be merged into one reloc section 376 and sorted so that relocs against the same symbol come together. */ 377 unsigned int combreloc: 1; 378 379 /* TRUE if a default symbol version should be created and used for 380 imported symbols. */ 381 unsigned int default_imported_symver: 1; 382 383 /* TRUE if the new ELF dynamic tags are enabled. */ 384 unsigned int new_dtags: 1; 385 386 /* FALSE if .eh_frame unwind info should be generated for PLT and other 387 linker created sections, TRUE if it should be omitted. */ 388 unsigned int no_ld_generated_unwind_info: 1; 389 390 /* TRUE if BFD should generate a "task linked" object file, 391 similar to relocatable but also with globals converted to 392 statics. */ 393 unsigned int task_link: 1; 394 395 /* TRUE if ok to have multiple definition. */ 396 unsigned int allow_multiple_definition: 1; 397 398 /* TRUE if ok to have version with no definition. */ 399 unsigned int allow_undefined_version: 1; 400 401 /* TRUE if some symbols have to be dynamic, controlled by 402 --dynamic-list command line options. */ 403 unsigned int dynamic: 1; 404 405 /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X 406 flags. */ 407 unsigned int execstack: 1; 408 409 /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W 410 flags. */ 411 unsigned int noexecstack: 1; 412 413 /* TRUE if we want to produced optimized output files. This might 414 need much more time and therefore must be explicitly selected. */ 415 unsigned int optimize: 1; 416 417 /* TRUE if user should be informed of removed unreferenced sections. */ 418 unsigned int print_gc_sections: 1; 419 420 /* TRUE if we should warn alternate ELF machine code. */ 421 unsigned int warn_alternate_em: 1; 422 423 /* TRUE if the linker script contained an explicit PHDRS command. */ 424 unsigned int user_phdrs: 1; 425 426 /* TRUE if BND prefix in PLT entries is always generated. */ 427 unsigned int bndplt: 1; 428 429 /* Char that may appear as the first char of a symbol, but should be 430 skipped (like symbol_leading_char) when looking up symbols in 431 wrap_hash. Used by PowerPC Linux for 'dot' symbols. */ 432 char wrap_char; 433 434 /* Separator between archive and filename in linker script filespecs. */ 435 char path_separator; 436 437 /* Default stack size. Zero means default (often zero itself), -1 438 means explicitly zero-sized. */ 439 bfd_signed_vma stacksize; 440 441 /* Enable or disable target specific optimizations. 442 443 Not all targets have optimizations to enable. 444 445 Normally these optimizations are disabled by default but some targets 446 prefer to enable them by default. So this field is a tri-state variable. 447 The values are: 448 449 zero: Enable the optimizations (either from --relax being specified on 450 the command line or the backend's before_allocation emulation function. 451 452 positive: The user has requested that these optimizations be disabled. 453 (Via the --no-relax command line option). 454 455 negative: The optimizations are disabled. (Set when initializing the 456 args_type structure in ldmain.c:main. */ 457 signed int disable_target_specific_optimizations; 458 459 /* Function callbacks. */ 460 const struct bfd_link_callbacks *callbacks; 461 462 /* Hash table handled by BFD. */ 463 struct bfd_link_hash_table *hash; 464 465 /* Hash table of symbols to keep. This is NULL unless strip is 466 strip_some. */ 467 struct bfd_hash_table *keep_hash; 468 469 /* Hash table of symbols to report back via the notice callback. If 470 this is NULL, and notice_all is FALSE, then no symbols are 471 reported back. */ 472 struct bfd_hash_table *notice_hash; 473 474 /* Hash table of symbols which are being wrapped (the --wrap linker 475 option). If this is NULL, no symbols are being wrapped. */ 476 struct bfd_hash_table *wrap_hash; 477 478 /* Hash table of symbols which may be left unresolved during 479 a link. If this is NULL, no symbols can be left unresolved. */ 480 struct bfd_hash_table *ignore_hash; 481 482 /* The output BFD. */ 483 bfd *output_bfd; 484 485 /* The list of input BFD's involved in the link. These are chained 486 together via the link.next field. */ 487 bfd *input_bfds; 488 bfd **input_bfds_tail; 489 490 /* If a symbol should be created for each input BFD, this is section 491 where those symbols should be placed. It must be a section in 492 the output BFD. It may be NULL, in which case no such symbols 493 will be created. This is to support CREATE_OBJECT_SYMBOLS in the 494 linker command language. */ 495 asection *create_object_symbols_section; 496 497 /* List of global symbol names that are starting points for marking 498 sections against garbage collection. */ 499 struct bfd_sym_chain *gc_sym_list; 500 501 /* If a base output file is wanted, then this points to it */ 502 void *base_file; 503 504 /* The function to call when the executable or shared object is 505 loaded. */ 506 const char *init_function; 507 508 /* The function to call when the executable or shared object is 509 unloaded. */ 510 const char *fini_function; 511 512 /* Number of relaxation passes. Usually only one relaxation pass 513 is needed. But a backend can have as many relaxation passes as 514 necessary. During bfd_relax_section call, it is set to the 515 current pass, starting from 0. */ 516 int relax_pass; 517 518 /* Number of relaxation trips. This number is incremented every 519 time the relaxation pass is restarted due to a previous 520 relaxation returning true in *AGAIN. */ 521 int relax_trip; 522 523 /* Non-zero if auto-import thunks for DATA items in pei386 DLLs 524 should be generated/linked against. Set to 1 if this feature 525 is explicitly requested by the user, -1 if enabled by default. */ 526 int pei386_auto_import; 527 528 /* Non-zero if runtime relocs for DATA items with non-zero addends 529 in pei386 DLLs should be generated. Set to 1 if this feature 530 is explicitly requested by the user, -1 if enabled by default. */ 531 int pei386_runtime_pseudo_reloc; 532 533 /* How many spare .dynamic DT_NULL entries should be added? */ 534 unsigned int spare_dynamic_tags; 535 536 /* May be used to set DT_FLAGS for ELF. */ 537 bfd_vma flags; 538 539 /* May be used to set DT_FLAGS_1 for ELF. */ 540 bfd_vma flags_1; 541 542 /* Start and end of RELRO region. */ 543 bfd_vma relro_start, relro_end; 544 545 /* List of symbols should be dynamic. */ 546 struct bfd_elf_dynamic_list *dynamic_list; 547 548 /* The version information. */ 549 struct bfd_elf_version_tree *version_info; 550 }; 551 552 /* This structures holds a set of callback functions. These are called 553 by the BFD linker routines. Except for the info functions, the first 554 argument to each callback function is the bfd_link_info structure 555 being used and each function returns a boolean value. If the 556 function returns FALSE, then the BFD function which called it should 557 return with a failure indication. */ 558 559 struct bfd_link_callbacks 560 { 561 /* A function which is called when an object is added from an 562 archive. ABFD is the archive element being added. NAME is the 563 name of the symbol which caused the archive element to be pulled 564 in. This function may set *SUBSBFD to point to an alternative 565 BFD from which symbols should in fact be added in place of the 566 original BFD's symbols. */ 567 bfd_boolean (*add_archive_element) 568 (struct bfd_link_info *, bfd *abfd, const char *name, bfd **subsbfd); 569 /* A function which is called when a symbol is found with multiple 570 definitions. H is the symbol which is defined multiple times. 571 NBFD is the new BFD, NSEC is the new section, and NVAL is the new 572 value. NSEC may be bfd_com_section or bfd_ind_section. */ 573 bfd_boolean (*multiple_definition) 574 (struct bfd_link_info *, struct bfd_link_hash_entry *h, 575 bfd *nbfd, asection *nsec, bfd_vma nval); 576 /* A function which is called when a common symbol is defined 577 multiple times. H is the symbol appearing multiple times. 578 NBFD is the BFD of the new symbol. NTYPE is the type of the new 579 symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or 580 bfd_link_hash_indirect. If NTYPE is bfd_link_hash_common, NSIZE 581 is the size of the new symbol. */ 582 bfd_boolean (*multiple_common) 583 (struct bfd_link_info *, struct bfd_link_hash_entry *h, 584 bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize); 585 /* A function which is called to add a symbol to a set. ENTRY is 586 the link hash table entry for the set itself (e.g., 587 __CTOR_LIST__). RELOC is the relocation to use for an entry in 588 the set when generating a relocatable file, and is also used to 589 get the size of the entry when generating an executable file. 590 ABFD, SEC and VALUE identify the value to add to the set. */ 591 bfd_boolean (*add_to_set) 592 (struct bfd_link_info *, struct bfd_link_hash_entry *entry, 593 bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value); 594 /* A function which is called when the name of a g++ constructor or 595 destructor is found. This is only called by some object file 596 formats. CONSTRUCTOR is TRUE for a constructor, FALSE for a 597 destructor. This will use BFD_RELOC_CTOR when generating a 598 relocatable file. NAME is the name of the symbol found. ABFD, 599 SECTION and VALUE are the value of the symbol. */ 600 bfd_boolean (*constructor) 601 (struct bfd_link_info *, bfd_boolean constructor, const char *name, 602 bfd *abfd, asection *sec, bfd_vma value); 603 /* A function which is called to issue a linker warning. For 604 example, this is called when there is a reference to a warning 605 symbol. WARNING is the warning to be issued. SYMBOL is the name 606 of the symbol which triggered the warning; it may be NULL if 607 there is none. ABFD, SECTION and ADDRESS identify the location 608 which trigerred the warning; either ABFD or SECTION or both may 609 be NULL if the location is not known. */ 610 bfd_boolean (*warning) 611 (struct bfd_link_info *, const char *warning, const char *symbol, 612 bfd *abfd, asection *section, bfd_vma address); 613 /* A function which is called when a relocation is attempted against 614 an undefined symbol. NAME is the symbol which is undefined. 615 ABFD, SECTION and ADDRESS identify the location from which the 616 reference is made. IS_FATAL indicates whether an undefined symbol is 617 a fatal error or not. In some cases SECTION may be NULL. */ 618 bfd_boolean (*undefined_symbol) 619 (struct bfd_link_info *, const char *name, bfd *abfd, 620 asection *section, bfd_vma address, bfd_boolean is_fatal); 621 /* A function which is called when a reloc overflow occurs. ENTRY is 622 the link hash table entry for the symbol the reloc is against. 623 NAME is the name of the local symbol or section the reloc is 624 against, RELOC_NAME is the name of the relocation, and ADDEND is 625 any addend that is used. ABFD, SECTION and ADDRESS identify the 626 location at which the overflow occurs; if this is the result of a 627 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then 628 ABFD will be NULL. */ 629 bfd_boolean (*reloc_overflow) 630 (struct bfd_link_info *, struct bfd_link_hash_entry *entry, 631 const char *name, const char *reloc_name, bfd_vma addend, 632 bfd *abfd, asection *section, bfd_vma address); 633 /* A function which is called when a dangerous reloc is performed. 634 MESSAGE is an appropriate message. 635 ABFD, SECTION and ADDRESS identify the location at which the 636 problem occurred; if this is the result of a 637 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then 638 ABFD will be NULL. */ 639 bfd_boolean (*reloc_dangerous) 640 (struct bfd_link_info *, const char *message, 641 bfd *abfd, asection *section, bfd_vma address); 642 /* A function which is called when a reloc is found to be attached 643 to a symbol which is not being written out. NAME is the name of 644 the symbol. ABFD, SECTION and ADDRESS identify the location of 645 the reloc; if this is the result of a 646 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then 647 ABFD will be NULL. */ 648 bfd_boolean (*unattached_reloc) 649 (struct bfd_link_info *, const char *name, 650 bfd *abfd, asection *section, bfd_vma address); 651 /* A function which is called when a symbol in notice_hash is 652 defined or referenced. H is the symbol, INH the indirect symbol 653 if applicable. ABFD, SECTION and ADDRESS are the (new) value of 654 the symbol. If SECTION is bfd_und_section, this is a reference. 655 FLAGS are the symbol BSF_* flags. */ 656 bfd_boolean (*notice) 657 (struct bfd_link_info *, struct bfd_link_hash_entry *h, 658 struct bfd_link_hash_entry *inh, 659 bfd *abfd, asection *section, bfd_vma address, flagword flags); 660 /* Error or warning link info message. */ 661 void (*einfo) 662 (const char *fmt, ...); 663 /* General link info message. */ 664 void (*info) 665 (const char *fmt, ...); 666 /* Message to be printed in linker map file. */ 667 void (*minfo) 668 (const char *fmt, ...); 669 /* This callback provides a chance for users of the BFD library to 670 override its decision about whether to place two adjacent sections 671 into the same segment. */ 672 bfd_boolean (*override_segment_assignment) 673 (struct bfd_link_info *, bfd * abfd, 674 asection * current_section, asection * previous_section, 675 bfd_boolean new_segment); 676 }; 677 678 /* The linker builds link_order structures which tell the code how to 679 include input data in the output file. */ 680 681 /* These are the types of link_order structures. */ 682 683 enum bfd_link_order_type 684 { 685 bfd_undefined_link_order, /* Undefined. */ 686 bfd_indirect_link_order, /* Built from a section. */ 687 bfd_data_link_order, /* Set to explicit data. */ 688 bfd_section_reloc_link_order, /* Relocate against a section. */ 689 bfd_symbol_reloc_link_order /* Relocate against a symbol. */ 690 }; 691 692 /* This is the link_order structure itself. These form a chain 693 attached to the output section whose contents they are describing. */ 694 695 struct bfd_link_order 696 { 697 /* Next link_order in chain. */ 698 struct bfd_link_order *next; 699 /* Type of link_order. */ 700 enum bfd_link_order_type type; 701 /* Offset within output section. */ 702 bfd_vma offset; 703 /* Size within output section. */ 704 bfd_size_type size; 705 /* Type specific information. */ 706 union 707 { 708 struct 709 { 710 /* Section to include. If this is used, then 711 section->output_section must be the section the 712 link_order is attached to, section->output_offset must 713 equal the link_order offset field, and section->size 714 must equal the link_order size field. Maybe these 715 restrictions should be relaxed someday. */ 716 asection *section; 717 } indirect; 718 struct 719 { 720 /* Size of contents, or zero when contents should be filled by 721 the architecture-dependent fill function. 722 A non-zero value allows filling of the output section 723 with an arbitrary repeated pattern. */ 724 unsigned int size; 725 /* Data to put into file. */ 726 bfd_byte *contents; 727 } data; 728 struct 729 { 730 /* Description of reloc to generate. Used for 731 bfd_section_reloc_link_order and 732 bfd_symbol_reloc_link_order. */ 733 struct bfd_link_order_reloc *p; 734 } reloc; 735 } u; 736 }; 737 738 /* A linker order of type bfd_section_reloc_link_order or 739 bfd_symbol_reloc_link_order means to create a reloc against a 740 section or symbol, respectively. This is used to implement -Ur to 741 generate relocs for the constructor tables. The 742 bfd_link_order_reloc structure describes the reloc that BFD should 743 create. It is similar to a arelent, but I didn't use arelent 744 because the linker does not know anything about most symbols, and 745 any asymbol structure it creates will be partially meaningless. 746 This information could logically be in the bfd_link_order struct, 747 but I didn't want to waste the space since these types of relocs 748 are relatively rare. */ 749 750 struct bfd_link_order_reloc 751 { 752 /* Reloc type. */ 753 bfd_reloc_code_real_type reloc; 754 755 union 756 { 757 /* For type bfd_section_reloc_link_order, this is the section 758 the reloc should be against. This must be a section in the 759 output BFD, not any of the input BFDs. */ 760 asection *section; 761 /* For type bfd_symbol_reloc_link_order, this is the name of the 762 symbol the reloc should be against. */ 763 const char *name; 764 } u; 765 766 /* Addend to use. The object file should contain zero. The BFD 767 backend is responsible for filling in the contents of the object 768 file correctly. For some object file formats (e.g., COFF) the 769 addend must be stored into in the object file, and for some 770 (e.g., SPARC a.out) it is kept in the reloc. */ 771 bfd_vma addend; 772 }; 773 774 /* Allocate a new link_order for a section. */ 775 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *); 776 777 /* These structures are used to describe version information for the 778 ELF linker. These structures could be manipulated entirely inside 779 BFD, but it would be a pain. Instead, the regular linker sets up 780 these structures, and then passes them into BFD. */ 781 782 /* Glob pattern for a version. */ 783 784 struct bfd_elf_version_expr 785 { 786 /* Next glob pattern for this version. */ 787 struct bfd_elf_version_expr *next; 788 /* Glob pattern. */ 789 const char *pattern; 790 /* Set if pattern is not a glob. */ 791 unsigned int literal : 1; 792 /* Defined by ".symver". */ 793 unsigned int symver : 1; 794 /* Defined by version script. */ 795 unsigned int script : 1; 796 /* Pattern type. */ 797 #define BFD_ELF_VERSION_C_TYPE 1 798 #define BFD_ELF_VERSION_CXX_TYPE 2 799 #define BFD_ELF_VERSION_JAVA_TYPE 4 800 unsigned int mask : 3; 801 }; 802 803 struct bfd_elf_version_expr_head 804 { 805 /* List of all patterns, both wildcards and non-wildcards. */ 806 struct bfd_elf_version_expr *list; 807 /* Hash table for non-wildcards. */ 808 void *htab; 809 /* Remaining patterns. */ 810 struct bfd_elf_version_expr *remaining; 811 /* What kind of pattern types are present in list (bitmask). */ 812 unsigned int mask; 813 }; 814 815 /* Version dependencies. */ 816 817 struct bfd_elf_version_deps 818 { 819 /* Next dependency for this version. */ 820 struct bfd_elf_version_deps *next; 821 /* The version which this version depends upon. */ 822 struct bfd_elf_version_tree *version_needed; 823 }; 824 825 /* A node in the version tree. */ 826 827 struct bfd_elf_version_tree 828 { 829 /* Next version. */ 830 struct bfd_elf_version_tree *next; 831 /* Name of this version. */ 832 const char *name; 833 /* Version number. */ 834 unsigned int vernum; 835 /* Regular expressions for global symbols in this version. */ 836 struct bfd_elf_version_expr_head globals; 837 /* Regular expressions for local symbols in this version. */ 838 struct bfd_elf_version_expr_head locals; 839 /* List of versions which this version depends upon. */ 840 struct bfd_elf_version_deps *deps; 841 /* Index of the version name. This is used within BFD. */ 842 unsigned int name_indx; 843 /* Whether this version tree was used. This is used within BFD. */ 844 int used; 845 /* Matching hook. */ 846 struct bfd_elf_version_expr *(*match) 847 (struct bfd_elf_version_expr_head *head, 848 struct bfd_elf_version_expr *prev, const char *sym); 849 }; 850 851 struct bfd_elf_dynamic_list 852 { 853 struct bfd_elf_version_expr_head head; 854 struct bfd_elf_version_expr *(*match) 855 (struct bfd_elf_version_expr_head *head, 856 struct bfd_elf_version_expr *prev, const char *sym); 857 }; 858 859 #endif 860