1 /* bfdlink.h -- header file for BFD link routines
2 Copyright (C) 1993-2017 Free Software Foundation, Inc.
3 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
5 This file is part of BFD, the Binary File Descriptor library.
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.
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.
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. */
25 /* Which symbols to strip during a link. */
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. */
34 /* Which local symbols to discard during a link. This is irrelevant
35 if strip_all is used. */
38 discard_sec_merge, /* Discard local temporary symbols in SEC_MERGE
40 discard_none, /* Don't discard any locals. */
41 discard_l, /* Discard local temporary symbols. */
42 discard_all /* Discard all locals. */
45 /* Whether to generate ELF common symbols with the STT_COMMON type
46 during a relocatable link. */
47 enum bfd_link_elf_stt_common
54 /* Describes the type of hash table entry structure being used.
55 Different hash table structure have different fields and so
56 support different linking features. */
57 enum bfd_link_hash_table_type
59 bfd_link_generic_hash_table,
60 bfd_link_elf_hash_table
63 /* These are the possible types of an entry in the BFD link hash
66 enum bfd_link_hash_type
68 bfd_link_hash_new, /* Symbol is new. */
69 bfd_link_hash_undefined, /* Symbol seen before, but undefined. */
70 bfd_link_hash_undefweak, /* Symbol is weak and undefined. */
71 bfd_link_hash_defined, /* Symbol is defined. */
72 bfd_link_hash_defweak, /* Symbol is weak and defined. */
73 bfd_link_hash_common, /* Symbol is common. */
74 bfd_link_hash_indirect, /* Symbol is an indirect link. */
75 bfd_link_hash_warning /* Like indirect, but warn if referenced. */
78 enum bfd_link_common_skip_ar_symbols
80 bfd_link_common_skip_none,
81 bfd_link_common_skip_text,
82 bfd_link_common_skip_data,
83 bfd_link_common_skip_all
86 struct bfd_link_hash_common_entry
88 unsigned int alignment_power; /* Alignment. */
89 asection *section; /* Symbol section. */
92 /* The linking routines use a hash table which uses this structure for
95 struct bfd_link_hash_entry
97 /* Base hash table entry structure. */
98 struct bfd_hash_entry root;
100 /* Type of this entry. */
101 ENUM_BITFIELD (bfd_link_hash_type) type : 8;
103 /* Symbol is referenced in a normal regular object file,
104 as distinct from a LTO IR object file. */
105 unsigned int non_ir_ref_regular : 1;
107 /* Symbol is referenced in a normal dynamic object file,
108 as distinct from a LTO IR object file. */
109 unsigned int non_ir_ref_dynamic : 1;
111 /* Symbol is a built-in define. These will be overridden by PROVIDE
112 in a linker script. */
113 unsigned int linker_def : 1;
115 /* Symbol defined in a linker script. */
116 unsigned int ldscript_def : 1;
118 /* A union of information depending upon the type. */
121 /* Nothing is kept for bfd_hash_new. */
122 /* bfd_link_hash_undefined, bfd_link_hash_undefweak. */
125 /* Undefined and common symbols are kept in a linked list through
126 this field. This field is present in all of the union element
127 so that we don't need to remove entries from the list when we
128 change their type. Removing entries would either require the
129 list to be doubly linked, which would waste more memory, or
130 require a traversal. When an undefined or common symbol is
131 created, it should be added to this list, the head of which is in
132 the link hash table itself. As symbols are defined, they need
133 not be removed from the list; anything which reads the list must
134 doublecheck the symbol type.
136 Weak symbols are not kept on this list.
138 Defined and defweak symbols use this field as a reference marker.
139 If the field is not NULL, or this structure is the tail of the
140 undefined symbol list, the symbol has been referenced. If the
141 symbol is undefined and becomes defined, this field will
142 automatically be non-NULL since the symbol will have been on the
143 undefined symbol list. */
144 struct bfd_link_hash_entry *next;
145 /* BFD symbol was found in. */
147 /* For __start_<name> and __stop_<name> symbols, the first
148 input section matching the name. */
151 /* bfd_link_hash_defined, bfd_link_hash_defweak. */
154 struct bfd_link_hash_entry *next;
155 /* Symbol section. */
160 /* bfd_link_hash_indirect, bfd_link_hash_warning. */
163 struct bfd_link_hash_entry *next;
165 struct bfd_link_hash_entry *link;
166 /* Warning message (bfd_link_hash_warning only). */
169 /* bfd_link_hash_common. */
172 struct bfd_link_hash_entry *next;
173 /* The linker needs to know three things about common
174 symbols: the size, the alignment, and the section in
175 which the symbol should be placed. We store the size
176 here, and we allocate a small structure to hold the
177 section and the alignment. The alignment is stored as a
178 power of two. We don't store all the information
179 directly because we don't want to increase the size of
180 the union; this structure is a major space user in the
182 struct bfd_link_hash_common_entry *p;
183 /* Common symbol size. */
189 /* This is the link hash table. It is a derived class of
192 struct bfd_link_hash_table
194 /* The hash table itself. */
195 struct bfd_hash_table table;
196 /* A linked list of undefined and common symbols, linked through the
197 next field in the bfd_link_hash_entry structure. */
198 struct bfd_link_hash_entry *undefs;
199 /* Entries are added to the tail of the undefs list. */
200 struct bfd_link_hash_entry *undefs_tail;
201 /* Function to free the hash table on closing BFD. */
202 void (*hash_table_free) (bfd *);
203 /* The type of the link hash table. */
204 enum bfd_link_hash_table_type type;
207 /* Look up an entry in a link hash table. If FOLLOW is TRUE, this
208 follows bfd_link_hash_indirect and bfd_link_hash_warning links to
210 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
211 (struct bfd_link_hash_table *, const char *, bfd_boolean create,
212 bfd_boolean copy, bfd_boolean follow);
214 /* Look up an entry in the main linker hash table if the symbol might
215 be wrapped. This should only be used for references to an
216 undefined symbol, not for definitions of a symbol. */
218 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
219 (bfd *, struct bfd_link_info *, const char *, bfd_boolean,
220 bfd_boolean, bfd_boolean);
222 /* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_"
223 and the remainder is found in wrap_hash, return the real symbol. */
225 extern struct bfd_link_hash_entry *unwrap_hash_lookup
226 (struct bfd_link_info *, bfd *, struct bfd_link_hash_entry *);
228 /* Traverse a link hash table. */
229 extern void bfd_link_hash_traverse
230 (struct bfd_link_hash_table *,
231 bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
234 /* Add an entry to the undefs list. */
235 extern void bfd_link_add_undef
236 (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
238 /* Remove symbols from the undefs list that don't belong there. */
239 extern void bfd_link_repair_undef_list
240 (struct bfd_link_hash_table *table);
242 /* Read symbols and cache symbol pointer array in outsymbols. */
243 extern bfd_boolean bfd_generic_link_read_symbols (bfd *);
245 /* Check the relocs in the BFD. Called after all the input
246 files have been loaded, and garbage collection has tagged
247 any unneeded sections. */
248 extern bfd_boolean bfd_link_check_relocs (bfd *,struct bfd_link_info *);
252 struct bfd_sym_chain *next;
256 /* How to handle unresolved symbols.
257 There are four possibilities which are enumerated below: */
260 /* This is the initial value when then link_info structure is created.
261 It allows the various stages of the linker to determine whether they
262 allowed to set the value. */
269 typedef enum {with_flags, without_flags} flag_type;
271 /* A section flag list. */
272 struct flag_info_list
277 struct flag_info_list *next;
280 /* Section flag info. */
283 flagword only_with_flags;
284 flagword not_with_flags;
285 struct flag_info_list *flag_list;
286 bfd_boolean flags_initialized;
289 struct bfd_elf_dynamic_list;
290 struct bfd_elf_version_tree;
292 /* Types of output. */
302 #define bfd_link_pde(info) ((info)->type == type_pde)
303 #define bfd_link_dll(info) ((info)->type == type_dll)
304 #define bfd_link_relocatable(info) ((info)->type == type_relocatable)
305 #define bfd_link_pie(info) ((info)->type == type_pie)
306 #define bfd_link_executable(info) (bfd_link_pde (info) || bfd_link_pie (info))
307 #define bfd_link_pic(info) (bfd_link_dll (info) || bfd_link_pie (info))
309 /* This structure holds all the information needed to communicate
310 between BFD and the linker when doing a link. */
315 ENUM_BITFIELD (output_type) type : 2;
317 /* TRUE if BFD should pre-bind symbols in a shared object. */
318 unsigned int symbolic: 1;
320 /* TRUE if executable should not contain copy relocs.
321 Setting this true may result in a non-sharable text segment. */
322 unsigned int nocopyreloc: 1;
324 /* TRUE if BFD should export all symbols in the dynamic symbol table
325 of an executable, rather than only those used. */
326 unsigned int export_dynamic: 1;
328 /* TRUE if a default symbol version should be created and used for
330 unsigned int create_default_symver: 1;
332 /* TRUE if unreferenced sections should be removed. */
333 unsigned int gc_sections: 1;
335 /* TRUE if exported symbols should be kept during section gc. */
336 unsigned int gc_keep_exported: 1;
338 /* TRUE if every symbol should be reported back via the notice
340 unsigned int notice_all: 1;
342 /* TRUE if the LTO plugin is active. */
343 unsigned int lto_plugin_active: 1;
345 /* TRUE if global symbols in discarded sections should be stripped. */
346 unsigned int strip_discarded: 1;
348 /* TRUE if all data symbols should be dynamic. */
349 unsigned int dynamic_data: 1;
351 /* Which symbols to strip. */
352 ENUM_BITFIELD (bfd_link_strip) strip : 2;
354 /* Which local symbols to discard. */
355 ENUM_BITFIELD (bfd_link_discard) discard : 2;
357 /* Whether to generate ELF common symbols with the STT_COMMON type. */
358 ENUM_BITFIELD (bfd_link_elf_stt_common) elf_stt_common : 2;
360 /* Criteria for skipping symbols when determining
361 whether to include an object from an archive. */
362 ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2;
364 /* What to do with unresolved symbols in an object file.
365 When producing executables the default is GENERATE_ERROR.
366 When producing shared libraries the default is IGNORE. The
367 assumption with shared libraries is that the reference will be
368 resolved at load/execution time. */
369 ENUM_BITFIELD (report_method) unresolved_syms_in_objects : 2;
371 /* What to do with unresolved symbols in a shared library.
372 The same defaults apply. */
373 ENUM_BITFIELD (report_method) unresolved_syms_in_shared_libs : 2;
375 /* TRUE if shared objects should be linked directly, not shared. */
376 unsigned int static_link: 1;
378 /* TRUE if symbols should be retained in memory, FALSE if they
379 should be freed and reread. */
380 unsigned int keep_memory: 1;
382 /* TRUE if BFD should generate relocation information in the final
384 unsigned int emitrelocations: 1;
386 /* TRUE if PT_GNU_RELRO segment should be created. */
387 unsigned int relro: 1;
389 /* Nonzero if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
390 should be created. 1 for DWARF2 tables, 2 for compact tables. */
391 unsigned int eh_frame_hdr_type: 2;
393 /* TRUE if we should warn when adding a DT_TEXTREL to a shared object. */
394 unsigned int warn_shared_textrel: 1;
396 /* TRUE if we should error when adding a DT_TEXTREL. */
397 unsigned int error_textrel: 1;
399 /* TRUE if .hash section should be created. */
400 unsigned int emit_hash: 1;
402 /* TRUE if .gnu.hash section should be created. */
403 unsigned int emit_gnu_hash: 1;
405 /* If TRUE reduce memory overheads, at the expense of speed. This will
406 cause map file generation to use an O(N^2) algorithm and disable
407 caching ELF symbol buffer. */
408 unsigned int reduce_memory_overheads: 1;
410 /* TRUE if the output file should be in a traditional format. This
411 is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
412 on the output file, but may be checked when reading the input
414 unsigned int traditional_format: 1;
416 /* TRUE if non-PLT relocs should be merged into one reloc section
417 and sorted so that relocs against the same symbol come together. */
418 unsigned int combreloc: 1;
420 /* TRUE if a default symbol version should be created and used for
422 unsigned int default_imported_symver: 1;
424 /* TRUE if the new ELF dynamic tags are enabled. */
425 unsigned int new_dtags: 1;
427 /* FALSE if .eh_frame unwind info should be generated for PLT and other
428 linker created sections, TRUE if it should be omitted. */
429 unsigned int no_ld_generated_unwind_info: 1;
431 /* TRUE if BFD should generate a "task linked" object file,
432 similar to relocatable but also with globals converted to
434 unsigned int task_link: 1;
436 /* TRUE if ok to have multiple definition. */
437 unsigned int allow_multiple_definition: 1;
439 /* TRUE if ok to have version with no definition. */
440 unsigned int allow_undefined_version: 1;
442 /* TRUE if some symbols have to be dynamic, controlled by
443 --dynamic-list command line options. */
444 unsigned int dynamic: 1;
446 /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
448 unsigned int execstack: 1;
450 /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
452 unsigned int noexecstack: 1;
454 /* TRUE if we want to produced optimized output files. This might
455 need much more time and therefore must be explicitly selected. */
456 unsigned int optimize: 1;
458 /* TRUE if user should be informed of removed unreferenced sections. */
459 unsigned int print_gc_sections: 1;
461 /* TRUE if we should warn alternate ELF machine code. */
462 unsigned int warn_alternate_em: 1;
464 /* TRUE if the linker script contained an explicit PHDRS command. */
465 unsigned int user_phdrs: 1;
467 /* TRUE if we should check relocations after all input files have
469 unsigned int check_relocs_after_open_input: 1;
471 /* TRUE if BND prefix in PLT entries is always generated. */
472 unsigned int bndplt: 1;
474 /* TRUE if generation of .interp/PT_INTERP should be suppressed. */
475 unsigned int nointerp: 1;
477 /* TRUE if we shouldn't check relocation overflow. */
478 unsigned int no_reloc_overflow_check: 1;
480 /* TRUE if generate a 1-byte NOP as suffix for x86 call instruction. */
481 unsigned int call_nop_as_suffix : 1;
483 /* The 1-byte NOP for x86 call instruction. */
486 /* Char that may appear as the first char of a symbol, but should be
487 skipped (like symbol_leading_char) when looking up symbols in
488 wrap_hash. Used by PowerPC Linux for 'dot' symbols. */
491 /* Separator between archive and filename in linker script filespecs. */
494 /* Compress DWARF debug sections. */
495 enum compressed_debug_section_type compress_debug;
497 /* Default stack size. Zero means default (often zero itself), -1
498 means explicitly zero-sized. */
499 bfd_signed_vma stacksize;
501 /* Enable or disable target specific optimizations.
503 Not all targets have optimizations to enable.
505 Normally these optimizations are disabled by default but some targets
506 prefer to enable them by default. So this field is a tri-state variable.
509 zero: Enable the optimizations (either from --relax being specified on
510 the command line or the backend's before_allocation emulation function.
512 positive: The user has requested that these optimizations be disabled.
513 (Via the --no-relax command line option).
515 negative: The optimizations are disabled. (Set when initializing the
516 args_type structure in ldmain.c:main. */
517 signed int disable_target_specific_optimizations;
519 /* Function callbacks. */
520 const struct bfd_link_callbacks *callbacks;
522 /* Hash table handled by BFD. */
523 struct bfd_link_hash_table *hash;
525 /* Hash table of symbols to keep. This is NULL unless strip is
527 struct bfd_hash_table *keep_hash;
529 /* Hash table of symbols to report back via the notice callback. If
530 this is NULL, and notice_all is FALSE, then no symbols are
532 struct bfd_hash_table *notice_hash;
534 /* Hash table of symbols which are being wrapped (the --wrap linker
535 option). If this is NULL, no symbols are being wrapped. */
536 struct bfd_hash_table *wrap_hash;
538 /* Hash table of symbols which may be left unresolved during
539 a link. If this is NULL, no symbols can be left unresolved. */
540 struct bfd_hash_table *ignore_hash;
542 /* The output BFD. */
545 /* The import library generated. */
548 /* The list of input BFD's involved in the link. These are chained
549 together via the link.next field. */
551 bfd **input_bfds_tail;
553 /* If a symbol should be created for each input BFD, this is section
554 where those symbols should be placed. It must be a section in
555 the output BFD. It may be NULL, in which case no such symbols
556 will be created. This is to support CREATE_OBJECT_SYMBOLS in the
557 linker command language. */
558 asection *create_object_symbols_section;
560 /* List of global symbol names that are starting points for marking
561 sections against garbage collection. */
562 struct bfd_sym_chain *gc_sym_list;
564 /* If a base output file is wanted, then this points to it */
567 /* The function to call when the executable or shared object is
569 const char *init_function;
571 /* The function to call when the executable or shared object is
573 const char *fini_function;
575 /* Number of relaxation passes. Usually only one relaxation pass
576 is needed. But a backend can have as many relaxation passes as
577 necessary. During bfd_relax_section call, it is set to the
578 current pass, starting from 0. */
581 /* Number of relaxation trips. This number is incremented every
582 time the relaxation pass is restarted due to a previous
583 relaxation returning true in *AGAIN. */
586 /* > 0 to treat protected data defined in the shared library as
587 reference external. 0 to treat it as internal. -1 to let
588 backend to decide. */
589 int extern_protected_data;
591 /* 1 to make undefined weak symbols dynamic when building a dynamic
592 object. 0 to resolve undefined weak symbols to zero. -1 to let
593 the backend decide. */
594 int dynamic_undefined_weak;
596 /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
597 should be generated/linked against. Set to 1 if this feature
598 is explicitly requested by the user, -1 if enabled by default. */
599 int pei386_auto_import;
601 /* Non-zero if runtime relocs for DATA items with non-zero addends
602 in pei386 DLLs should be generated. Set to 1 if this feature
603 is explicitly requested by the user, -1 if enabled by default. */
604 int pei386_runtime_pseudo_reloc;
606 /* How many spare .dynamic DT_NULL entries should be added? */
607 unsigned int spare_dynamic_tags;
609 /* May be used to set DT_FLAGS for ELF. */
612 /* May be used to set DT_FLAGS_1 for ELF. */
615 /* Start and end of RELRO region. */
616 bfd_vma relro_start, relro_end;
618 /* List of symbols should be dynamic. */
619 struct bfd_elf_dynamic_list *dynamic_list;
621 /* The version information. */
622 struct bfd_elf_version_tree *version_info;
625 /* This structures holds a set of callback functions. These are called
626 by the BFD linker routines. */
628 struct bfd_link_callbacks
630 /* A function which is called when an object is added from an
631 archive. ABFD is the archive element being added. NAME is the
632 name of the symbol which caused the archive element to be pulled
633 in. This function may set *SUBSBFD to point to an alternative
634 BFD from which symbols should in fact be added in place of the
635 original BFD's symbols. Returns TRUE if the object should be
636 added, FALSE if it should be skipped. */
637 bfd_boolean (*add_archive_element)
638 (struct bfd_link_info *, bfd *abfd, const char *name, bfd **subsbfd);
639 /* A function which is called when a symbol is found with multiple
640 definitions. H is the symbol which is defined multiple times.
641 NBFD is the new BFD, NSEC is the new section, and NVAL is the new
642 value. NSEC may be bfd_com_section or bfd_ind_section. */
643 void (*multiple_definition)
644 (struct bfd_link_info *, struct bfd_link_hash_entry *h,
645 bfd *nbfd, asection *nsec, bfd_vma nval);
646 /* A function which is called when a common symbol is defined
647 multiple times. H is the symbol appearing multiple times.
648 NBFD is the BFD of the new symbol. NTYPE is the type of the new
649 symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
650 bfd_link_hash_indirect. If NTYPE is bfd_link_hash_common, NSIZE
651 is the size of the new symbol. */
652 void (*multiple_common)
653 (struct bfd_link_info *, struct bfd_link_hash_entry *h,
654 bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
655 /* A function which is called to add a symbol to a set. ENTRY is
656 the link hash table entry for the set itself (e.g.,
657 __CTOR_LIST__). RELOC is the relocation to use for an entry in
658 the set when generating a relocatable file, and is also used to
659 get the size of the entry when generating an executable file.
660 ABFD, SEC and VALUE identify the value to add to the set. */
662 (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
663 bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
664 /* A function which is called when the name of a g++ constructor or
665 destructor is found. This is only called by some object file
666 formats. CONSTRUCTOR is TRUE for a constructor, FALSE for a
667 destructor. This will use BFD_RELOC_CTOR when generating a
668 relocatable file. NAME is the name of the symbol found. ABFD,
669 SECTION and VALUE are the value of the symbol. */
671 (struct bfd_link_info *, bfd_boolean constructor, const char *name,
672 bfd *abfd, asection *sec, bfd_vma value);
673 /* A function which is called to issue a linker warning. For
674 example, this is called when there is a reference to a warning
675 symbol. WARNING is the warning to be issued. SYMBOL is the name
676 of the symbol which triggered the warning; it may be NULL if
677 there is none. ABFD, SECTION and ADDRESS identify the location
678 which trigerred the warning; either ABFD or SECTION or both may
679 be NULL if the location is not known. */
681 (struct bfd_link_info *, const char *warning, const char *symbol,
682 bfd *abfd, asection *section, bfd_vma address);
683 /* A function which is called when a relocation is attempted against
684 an undefined symbol. NAME is the symbol which is undefined.
685 ABFD, SECTION and ADDRESS identify the location from which the
686 reference is made. IS_FATAL indicates whether an undefined symbol is
687 a fatal error or not. In some cases SECTION may be NULL. */
688 void (*undefined_symbol)
689 (struct bfd_link_info *, const char *name, bfd *abfd,
690 asection *section, bfd_vma address, bfd_boolean is_fatal);
691 /* A function which is called when a reloc overflow occurs. ENTRY is
692 the link hash table entry for the symbol the reloc is against.
693 NAME is the name of the local symbol or section the reloc is
694 against, RELOC_NAME is the name of the relocation, and ADDEND is
695 any addend that is used. ABFD, SECTION and ADDRESS identify the
696 location at which the overflow occurs; if this is the result of a
697 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
698 ABFD will be NULL. */
699 void (*reloc_overflow)
700 (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
701 const char *name, const char *reloc_name, bfd_vma addend,
702 bfd *abfd, asection *section, bfd_vma address);
703 /* A function which is called when a dangerous reloc is performed.
704 MESSAGE is an appropriate message.
705 ABFD, SECTION and ADDRESS identify the location at which the
706 problem occurred; if this is the result of a
707 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
708 ABFD will be NULL. */
709 void (*reloc_dangerous)
710 (struct bfd_link_info *, const char *message,
711 bfd *abfd, asection *section, bfd_vma address);
712 /* A function which is called when a reloc is found to be attached
713 to a symbol which is not being written out. NAME is the name of
714 the symbol. ABFD, SECTION and ADDRESS identify the location of
715 the reloc; if this is the result of a
716 bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
717 ABFD will be NULL. */
718 void (*unattached_reloc)
719 (struct bfd_link_info *, const char *name,
720 bfd *abfd, asection *section, bfd_vma address);
721 /* A function which is called when a symbol in notice_hash is
722 defined or referenced. H is the symbol, INH the indirect symbol
723 if applicable. ABFD, SECTION and ADDRESS are the (new) value of
724 the symbol. If SECTION is bfd_und_section, this is a reference.
725 FLAGS are the symbol BSF_* flags. */
726 bfd_boolean (*notice)
727 (struct bfd_link_info *, struct bfd_link_hash_entry *h,
728 struct bfd_link_hash_entry *inh,
729 bfd *abfd, asection *section, bfd_vma address, flagword flags);
730 /* Error or warning link info message. */
732 (const char *fmt, ...);
733 /* General link info message. */
735 (const char *fmt, ...);
736 /* Message to be printed in linker map file. */
738 (const char *fmt, ...);
739 /* This callback provides a chance for users of the BFD library to
740 override its decision about whether to place two adjacent sections
741 into the same segment. */
742 bfd_boolean (*override_segment_assignment)
743 (struct bfd_link_info *, bfd * abfd,
744 asection * current_section, asection * previous_section,
745 bfd_boolean new_segment);
748 /* The linker builds link_order structures which tell the code how to
749 include input data in the output file. */
751 /* These are the types of link_order structures. */
753 enum bfd_link_order_type
755 bfd_undefined_link_order, /* Undefined. */
756 bfd_indirect_link_order, /* Built from a section. */
757 bfd_data_link_order, /* Set to explicit data. */
758 bfd_section_reloc_link_order, /* Relocate against a section. */
759 bfd_symbol_reloc_link_order /* Relocate against a symbol. */
762 /* This is the link_order structure itself. These form a chain
763 attached to the output section whose contents they are describing. */
765 struct bfd_link_order
767 /* Next link_order in chain. */
768 struct bfd_link_order *next;
769 /* Type of link_order. */
770 enum bfd_link_order_type type;
771 /* Offset within output section. */
773 /* Size within output section. */
775 /* Type specific information. */
780 /* Section to include. If this is used, then
781 section->output_section must be the section the
782 link_order is attached to, section->output_offset must
783 equal the link_order offset field, and section->size
784 must equal the link_order size field. Maybe these
785 restrictions should be relaxed someday. */
790 /* Size of contents, or zero when contents should be filled by
791 the architecture-dependent fill function.
792 A non-zero value allows filling of the output section
793 with an arbitrary repeated pattern. */
795 /* Data to put into file. */
800 /* Description of reloc to generate. Used for
801 bfd_section_reloc_link_order and
802 bfd_symbol_reloc_link_order. */
803 struct bfd_link_order_reloc *p;
808 /* A linker order of type bfd_section_reloc_link_order or
809 bfd_symbol_reloc_link_order means to create a reloc against a
810 section or symbol, respectively. This is used to implement -Ur to
811 generate relocs for the constructor tables. The
812 bfd_link_order_reloc structure describes the reloc that BFD should
813 create. It is similar to a arelent, but I didn't use arelent
814 because the linker does not know anything about most symbols, and
815 any asymbol structure it creates will be partially meaningless.
816 This information could logically be in the bfd_link_order struct,
817 but I didn't want to waste the space since these types of relocs
818 are relatively rare. */
820 struct bfd_link_order_reloc
823 bfd_reloc_code_real_type reloc;
827 /* For type bfd_section_reloc_link_order, this is the section
828 the reloc should be against. This must be a section in the
829 output BFD, not any of the input BFDs. */
831 /* For type bfd_symbol_reloc_link_order, this is the name of the
832 symbol the reloc should be against. */
836 /* Addend to use. The object file should contain zero. The BFD
837 backend is responsible for filling in the contents of the object
838 file correctly. For some object file formats (e.g., COFF) the
839 addend must be stored into in the object file, and for some
840 (e.g., SPARC a.out) it is kept in the reloc. */
844 /* Allocate a new link_order for a section. */
845 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
847 /* These structures are used to describe version information for the
848 ELF linker. These structures could be manipulated entirely inside
849 BFD, but it would be a pain. Instead, the regular linker sets up
850 these structures, and then passes them into BFD. */
852 /* Glob pattern for a version. */
854 struct bfd_elf_version_expr
856 /* Next glob pattern for this version. */
857 struct bfd_elf_version_expr *next;
860 /* Set if pattern is not a glob. */
861 unsigned int literal : 1;
862 /* Defined by ".symver". */
863 unsigned int symver : 1;
864 /* Defined by version script. */
865 unsigned int script : 1;
867 #define BFD_ELF_VERSION_C_TYPE 1
868 #define BFD_ELF_VERSION_CXX_TYPE 2
869 #define BFD_ELF_VERSION_JAVA_TYPE 4
870 unsigned int mask : 3;
873 struct bfd_elf_version_expr_head
875 /* List of all patterns, both wildcards and non-wildcards. */
876 struct bfd_elf_version_expr *list;
877 /* Hash table for non-wildcards. */
879 /* Remaining patterns. */
880 struct bfd_elf_version_expr *remaining;
881 /* What kind of pattern types are present in list (bitmask). */
885 /* Version dependencies. */
887 struct bfd_elf_version_deps
889 /* Next dependency for this version. */
890 struct bfd_elf_version_deps *next;
891 /* The version which this version depends upon. */
892 struct bfd_elf_version_tree *version_needed;
895 /* A node in the version tree. */
897 struct bfd_elf_version_tree
900 struct bfd_elf_version_tree *next;
901 /* Name of this version. */
903 /* Version number. */
905 /* Regular expressions for global symbols in this version. */
906 struct bfd_elf_version_expr_head globals;
907 /* Regular expressions for local symbols in this version. */
908 struct bfd_elf_version_expr_head locals;
909 /* List of versions which this version depends upon. */
910 struct bfd_elf_version_deps *deps;
911 /* Index of the version name. This is used within BFD. */
912 unsigned int name_indx;
913 /* Whether this version tree was used. This is used within BFD. */
916 struct bfd_elf_version_expr *(*match)
917 (struct bfd_elf_version_expr_head *head,
918 struct bfd_elf_version_expr *prev, const char *sym);
921 struct bfd_elf_dynamic_list
923 struct bfd_elf_version_expr_head head;
924 struct bfd_elf_version_expr *(*match)
925 (struct bfd_elf_version_expr_head *head,
926 struct bfd_elf_version_expr *prev, const char *sym);