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1 | /* bfdlink.h -- header file for BFD link routines | |
2 | Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, | |
3 | 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 | |
4 | Free Software Foundation, Inc. | |
5 | Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support. | |
6 | ||
7 | This file is part of BFD, the Binary File Descriptor library. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program; if not, write to the Free Software | |
21 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
22 | MA 02110-1301, USA. */ | |
23 | ||
24 | #ifndef BFDLINK_H | |
25 | #define BFDLINK_H | |
26 | ||
27 | /* Which symbols to strip during a link. */ | |
28 | enum bfd_link_strip | |
29 | { | |
30 | strip_none, /* Don't strip any symbols. */ | |
31 | strip_debugger, /* Strip debugging symbols. */ | |
32 | strip_some, /* keep_hash is the list of symbols to keep. */ | |
33 | strip_all /* Strip all symbols. */ | |
34 | }; | |
35 | ||
36 | /* Which local symbols to discard during a link. This is irrelevant | |
37 | if strip_all is used. */ | |
38 | enum bfd_link_discard | |
39 | { | |
40 | discard_sec_merge, /* Discard local temporary symbols in SEC_MERGE | |
41 | sections. */ | |
42 | discard_none, /* Don't discard any locals. */ | |
43 | discard_l, /* Discard local temporary symbols. */ | |
44 | discard_all /* Discard all locals. */ | |
45 | }; | |
46 | ||
47 | /* Describes the type of hash table entry structure being used. | |
48 | Different hash table structure have different fields and so | |
49 | support different linking features. */ | |
50 | enum bfd_link_hash_table_type | |
51 | { | |
52 | bfd_link_generic_hash_table, | |
53 | bfd_link_elf_hash_table | |
54 | }; | |
55 | \f | |
56 | /* These are the possible types of an entry in the BFD link hash | |
57 | table. */ | |
58 | ||
59 | enum bfd_link_hash_type | |
60 | { | |
61 | bfd_link_hash_new, /* Symbol is new. */ | |
62 | bfd_link_hash_undefined, /* Symbol seen before, but undefined. */ | |
63 | bfd_link_hash_undefweak, /* Symbol is weak and undefined. */ | |
64 | bfd_link_hash_defined, /* Symbol is defined. */ | |
65 | bfd_link_hash_defweak, /* Symbol is weak and defined. */ | |
66 | bfd_link_hash_common, /* Symbol is common. */ | |
67 | bfd_link_hash_indirect, /* Symbol is an indirect link. */ | |
68 | bfd_link_hash_warning /* Like indirect, but warn if referenced. */ | |
69 | }; | |
70 | ||
71 | enum bfd_link_common_skip_ar_symbols | |
72 | { | |
73 | bfd_link_common_skip_none, | |
74 | bfd_link_common_skip_text, | |
75 | bfd_link_common_skip_data, | |
76 | bfd_link_common_skip_all | |
77 | }; | |
78 | ||
79 | struct bfd_link_hash_common_entry | |
80 | { | |
81 | unsigned int alignment_power; /* Alignment. */ | |
82 | asection *section; /* Symbol section. */ | |
83 | }; | |
84 | ||
85 | /* The linking routines use a hash table which uses this structure for | |
86 | its elements. */ | |
87 | ||
88 | struct bfd_link_hash_entry | |
89 | { | |
90 | /* Base hash table entry structure. */ | |
91 | struct bfd_hash_entry root; | |
92 | ||
93 | /* Type of this entry. */ | |
94 | ENUM_BITFIELD (bfd_link_hash_type) type : 8; | |
95 | ||
96 | unsigned int non_ir_ref : 1; | |
97 | ||
98 | /* A union of information depending upon the type. */ | |
99 | union | |
100 | { | |
101 | /* Nothing is kept for bfd_hash_new. */ | |
102 | /* bfd_link_hash_undefined, bfd_link_hash_undefweak. */ | |
103 | struct | |
104 | { | |
105 | /* Undefined and common symbols are kept in a linked list through | |
106 | this field. This field is present in all of the union element | |
107 | so that we don't need to remove entries from the list when we | |
108 | change their type. Removing entries would either require the | |
109 | list to be doubly linked, which would waste more memory, or | |
110 | require a traversal. When an undefined or common symbol is | |
111 | created, it should be added to this list, the head of which is in | |
112 | the link hash table itself. As symbols are defined, they need | |
113 | not be removed from the list; anything which reads the list must | |
114 | doublecheck the symbol type. | |
115 | ||
116 | Weak symbols are not kept on this list. | |
117 | ||
118 | Defined and defweak symbols use this field as a reference marker. | |
119 | If the field is not NULL, or this structure is the tail of the | |
120 | undefined symbol list, the symbol has been referenced. If the | |
121 | symbol is undefined and becomes defined, this field will | |
122 | automatically be non-NULL since the symbol will have been on the | |
123 | undefined symbol list. */ | |
124 | struct bfd_link_hash_entry *next; | |
125 | bfd *abfd; /* BFD symbol was found in. */ | |
126 | } undef; | |
127 | /* bfd_link_hash_defined, bfd_link_hash_defweak. */ | |
128 | struct | |
129 | { | |
130 | struct bfd_link_hash_entry *next; | |
131 | asection *section; /* Symbol section. */ | |
132 | bfd_vma value; /* Symbol value. */ | |
133 | } def; | |
134 | /* bfd_link_hash_indirect, bfd_link_hash_warning. */ | |
135 | struct | |
136 | { | |
137 | struct bfd_link_hash_entry *next; | |
138 | struct bfd_link_hash_entry *link; /* Real symbol. */ | |
139 | const char *warning; /* Warning (bfd_link_hash_warning only). */ | |
140 | } i; | |
141 | /* bfd_link_hash_common. */ | |
142 | struct | |
143 | { | |
144 | struct bfd_link_hash_entry *next; | |
145 | /* The linker needs to know three things about common | |
146 | symbols: the size, the alignment, and the section in | |
147 | which the symbol should be placed. We store the size | |
148 | here, and we allocate a small structure to hold the | |
149 | section and the alignment. The alignment is stored as a | |
150 | power of two. We don't store all the information | |
151 | directly because we don't want to increase the size of | |
152 | the union; this structure is a major space user in the | |
153 | linker. */ | |
154 | struct bfd_link_hash_common_entry *p; | |
155 | bfd_size_type size; /* Common symbol size. */ | |
156 | } c; | |
157 | } u; | |
158 | }; | |
159 | ||
160 | /* This is the link hash table. It is a derived class of | |
161 | bfd_hash_table. */ | |
162 | ||
163 | struct bfd_link_hash_table | |
164 | { | |
165 | /* The hash table itself. */ | |
166 | struct bfd_hash_table table; | |
167 | /* A linked list of undefined and common symbols, linked through the | |
168 | next field in the bfd_link_hash_entry structure. */ | |
169 | struct bfd_link_hash_entry *undefs; | |
170 | /* Entries are added to the tail of the undefs list. */ | |
171 | struct bfd_link_hash_entry *undefs_tail; | |
172 | /* The type of the link hash table. */ | |
173 | enum bfd_link_hash_table_type type; | |
174 | }; | |
175 | ||
176 | /* Look up an entry in a link hash table. If FOLLOW is TRUE, this | |
177 | follows bfd_link_hash_indirect and bfd_link_hash_warning links to | |
178 | the real symbol. */ | |
179 | extern struct bfd_link_hash_entry *bfd_link_hash_lookup | |
180 | (struct bfd_link_hash_table *, const char *, bfd_boolean create, | |
181 | bfd_boolean copy, bfd_boolean follow); | |
182 | ||
183 | /* Look up an entry in the main linker hash table if the symbol might | |
184 | be wrapped. This should only be used for references to an | |
185 | undefined symbol, not for definitions of a symbol. */ | |
186 | ||
187 | extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup | |
188 | (bfd *, struct bfd_link_info *, const char *, bfd_boolean, | |
189 | bfd_boolean, bfd_boolean); | |
190 | ||
191 | /* Traverse a link hash table. */ | |
192 | extern void bfd_link_hash_traverse | |
193 | (struct bfd_link_hash_table *, | |
194 | bfd_boolean (*) (struct bfd_link_hash_entry *, void *), | |
195 | void *); | |
196 | ||
197 | /* Add an entry to the undefs list. */ | |
198 | extern void bfd_link_add_undef | |
199 | (struct bfd_link_hash_table *, struct bfd_link_hash_entry *); | |
200 | ||
201 | /* Remove symbols from the undefs list that don't belong there. */ | |
202 | extern void bfd_link_repair_undef_list | |
203 | (struct bfd_link_hash_table *table); | |
204 | ||
205 | /* Read symbols and cache symbol pointer array in outsymbols. */ | |
206 | extern bfd_boolean bfd_generic_link_read_symbols (bfd *); | |
207 | ||
208 | struct bfd_sym_chain | |
209 | { | |
210 | struct bfd_sym_chain *next; | |
211 | const char *name; | |
212 | }; | |
213 | \f | |
214 | /* How to handle unresolved symbols. | |
215 | There are four possibilities which are enumerated below: */ | |
216 | enum report_method | |
217 | { | |
218 | /* This is the initial value when then link_info structure is created. | |
219 | It allows the various stages of the linker to determine whether they | |
220 | allowed to set the value. */ | |
221 | RM_NOT_YET_SET = 0, | |
222 | RM_IGNORE, | |
223 | RM_GENERATE_WARNING, | |
224 | RM_GENERATE_ERROR | |
225 | }; | |
226 | ||
227 | typedef enum {with_flags, without_flags} flag_type; | |
228 | ||
229 | /* A section flag list. */ | |
230 | struct flag_info_list | |
231 | { | |
232 | flag_type with; | |
233 | const char *name; | |
234 | bfd_boolean valid; | |
235 | struct flag_info_list *next; | |
236 | }; | |
237 | ||
238 | /* Section flag info. */ | |
239 | struct flag_info | |
240 | { | |
241 | flagword only_with_flags; | |
242 | flagword not_with_flags; | |
243 | struct flag_info_list *flag_list; | |
244 | bfd_boolean flags_initialized; | |
245 | }; | |
246 | ||
247 | struct bfd_elf_dynamic_list; | |
248 | struct bfd_elf_version_tree; | |
249 | ||
250 | /* This structure holds all the information needed to communicate | |
251 | between BFD and the linker when doing a link. */ | |
252 | ||
253 | struct bfd_link_info | |
254 | { | |
255 | /* TRUE if BFD should generate a shared object (or a pie). */ | |
256 | unsigned int shared: 1; | |
257 | ||
258 | /* TRUE if generating an executable, position independent or not. */ | |
259 | unsigned int executable : 1; | |
260 | ||
261 | /* TRUE if generating a position independent executable. */ | |
262 | unsigned int pie: 1; | |
263 | ||
264 | /* TRUE if BFD should generate a relocatable object file. */ | |
265 | unsigned int relocatable: 1; | |
266 | ||
267 | /* TRUE if BFD should pre-bind symbols in a shared object. */ | |
268 | unsigned int symbolic: 1; | |
269 | ||
270 | /* TRUE if executable should not contain copy relocs. | |
271 | Setting this true may result in a non-sharable text segment. */ | |
272 | unsigned int nocopyreloc: 1; | |
273 | ||
274 | /* TRUE if BFD should export all symbols in the dynamic symbol table | |
275 | of an executable, rather than only those used. */ | |
276 | unsigned int export_dynamic: 1; | |
277 | ||
278 | /* TRUE if a default symbol version should be created and used for | |
279 | exported symbols. */ | |
280 | unsigned int create_default_symver: 1; | |
281 | ||
282 | /* TRUE if unreferenced sections should be removed. */ | |
283 | unsigned int gc_sections: 1; | |
284 | ||
285 | /* TRUE if every symbol should be reported back via the notice | |
286 | callback. */ | |
287 | unsigned int notice_all: 1; | |
288 | ||
289 | /* TRUE if we are loading LTO outputs. */ | |
290 | unsigned int loading_lto_outputs: 1; | |
291 | ||
292 | /* TRUE if global symbols in discarded sections should be stripped. */ | |
293 | unsigned int strip_discarded: 1; | |
294 | ||
295 | /* TRUE if all data symbols should be dynamic. */ | |
296 | unsigned int dynamic_data: 1; | |
297 | ||
298 | /* Which symbols to strip. */ | |
299 | ENUM_BITFIELD (bfd_link_strip) strip : 2; | |
300 | ||
301 | /* Which local symbols to discard. */ | |
302 | ENUM_BITFIELD (bfd_link_discard) discard : 2; | |
303 | ||
304 | /* Criteria for skipping symbols when determining | |
305 | whether to include an object from an archive. */ | |
306 | ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2; | |
307 | ||
308 | /* What to do with unresolved symbols in an object file. | |
309 | When producing executables the default is GENERATE_ERROR. | |
310 | When producing shared libraries the default is IGNORE. The | |
311 | assumption with shared libraries is that the reference will be | |
312 | resolved at load/execution time. */ | |
313 | ENUM_BITFIELD (report_method) unresolved_syms_in_objects : 2; | |
314 | ||
315 | /* What to do with unresolved symbols in a shared library. | |
316 | The same defaults apply. */ | |
317 | ENUM_BITFIELD (report_method) unresolved_syms_in_shared_libs : 2; | |
318 | ||
319 | /* TRUE if shared objects should be linked directly, not shared. */ | |
320 | unsigned int static_link: 1; | |
321 | ||
322 | /* TRUE if symbols should be retained in memory, FALSE if they | |
323 | should be freed and reread. */ | |
324 | unsigned int keep_memory: 1; | |
325 | ||
326 | /* TRUE if BFD should generate relocation information in the final | |
327 | executable. */ | |
328 | unsigned int emitrelocations: 1; | |
329 | ||
330 | /* TRUE if PT_GNU_RELRO segment should be created. */ | |
331 | unsigned int relro: 1; | |
332 | ||
333 | /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment | |
334 | should be created. */ | |
335 | unsigned int eh_frame_hdr: 1; | |
336 | ||
337 | /* TRUE if we should warn when adding a DT_TEXTREL to a shared object. */ | |
338 | unsigned int warn_shared_textrel: 1; | |
339 | ||
340 | /* TRUE if we should error when adding a DT_TEXTREL. */ | |
341 | unsigned int error_textrel: 1; | |
342 | ||
343 | /* TRUE if .hash section should be created. */ | |
344 | unsigned int emit_hash: 1; | |
345 | ||
346 | /* TRUE if .gnu.hash section should be created. */ | |
347 | unsigned int emit_gnu_hash: 1; | |
348 | ||
349 | /* If TRUE reduce memory overheads, at the expense of speed. This will | |
350 | cause map file generation to use an O(N^2) algorithm and disable | |
351 | caching ELF symbol buffer. */ | |
352 | unsigned int reduce_memory_overheads: 1; | |
353 | ||
354 | /* TRUE if the output file should be in a traditional format. This | |
355 | is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag | |
356 | on the output file, but may be checked when reading the input | |
357 | files. */ | |
358 | unsigned int traditional_format: 1; | |
359 | ||
360 | /* TRUE if non-PLT relocs should be merged into one reloc section | |
361 | and sorted so that relocs against the same symbol come together. */ | |
362 | unsigned int combreloc: 1; | |
363 | ||
364 | /* TRUE if a default symbol version should be created and used for | |
365 | imported symbols. */ | |
366 | unsigned int default_imported_symver: 1; | |
367 | ||
368 | /* TRUE if the new ELF dynamic tags are enabled. */ | |
369 | unsigned int new_dtags: 1; | |
370 | ||
371 | /* FALSE if .eh_frame unwind info should be generated for PLT and other | |
372 | linker created sections, TRUE if it should be omitted. */ | |
373 | unsigned int no_ld_generated_unwind_info: 1; | |
374 | ||
375 | /* TRUE if BFD should generate a "task linked" object file, | |
376 | similar to relocatable but also with globals converted to | |
377 | statics. */ | |
378 | unsigned int task_link: 1; | |
379 | ||
380 | /* TRUE if ok to have multiple definition. */ | |
381 | unsigned int allow_multiple_definition: 1; | |
382 | ||
383 | /* TRUE if ok to have version with no definition. */ | |
384 | unsigned int allow_undefined_version: 1; | |
385 | ||
386 | /* TRUE if some symbols have to be dynamic, controlled by | |
387 | --dynamic-list command line options. */ | |
388 | unsigned int dynamic: 1; | |
389 | ||
390 | /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X | |
391 | flags. */ | |
392 | unsigned int execstack: 1; | |
393 | ||
394 | /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W | |
395 | flags. */ | |
396 | unsigned int noexecstack: 1; | |
397 | ||
398 | /* TRUE if we want to produced optimized output files. This might | |
399 | need much more time and therefore must be explicitly selected. */ | |
400 | unsigned int optimize: 1; | |
401 | ||
402 | /* TRUE if user should be informed of removed unreferenced sections. */ | |
403 | unsigned int print_gc_sections: 1; | |
404 | ||
405 | /* TRUE if we should warn alternate ELF machine code. */ | |
406 | unsigned int warn_alternate_em: 1; | |
407 | ||
408 | /* TRUE if the linker script contained an explicit PHDRS command. */ | |
409 | unsigned int user_phdrs: 1; | |
410 | ||
411 | /* Char that may appear as the first char of a symbol, but should be | |
412 | skipped (like symbol_leading_char) when looking up symbols in | |
413 | wrap_hash. Used by PowerPC Linux for 'dot' symbols. */ | |
414 | char wrap_char; | |
415 | ||
416 | /* Separator between archive and filename in linker script filespecs. */ | |
417 | char path_separator; | |
418 | ||
419 | /* Default stack size. Zero means default (often zero itself), -1 | |
420 | means explicitly zero-sized. */ | |
421 | bfd_signed_vma stacksize; | |
422 | ||
423 | /* Enable or disable target specific optimizations. | |
424 | ||
425 | Not all targets have optimizations to enable. | |
426 | ||
427 | Normally these optimizations are disabled by default but some targets | |
428 | prefer to enable them by default. So this field is a tri-state variable. | |
429 | The values are: | |
430 | ||
431 | zero: Enable the optimizations (either from --relax being specified on | |
432 | the command line or the backend's before_allocation emulation function. | |
433 | ||
434 | positive: The user has requested that these optimizations be disabled. | |
435 | (Via the --no-relax command line option). | |
436 | ||
437 | negative: The optimizations are disabled. (Set when initializing the | |
438 | args_type structure in ldmain.c:main. */ | |
439 | signed int disable_target_specific_optimizations; | |
440 | ||
441 | /* Function callbacks. */ | |
442 | const struct bfd_link_callbacks *callbacks; | |
443 | ||
444 | /* Hash table handled by BFD. */ | |
445 | struct bfd_link_hash_table *hash; | |
446 | ||
447 | /* Hash table of symbols to keep. This is NULL unless strip is | |
448 | strip_some. */ | |
449 | struct bfd_hash_table *keep_hash; | |
450 | ||
451 | /* Hash table of symbols to report back via the notice callback. If | |
452 | this is NULL, and notice_all is FALSE, then no symbols are | |
453 | reported back. */ | |
454 | struct bfd_hash_table *notice_hash; | |
455 | ||
456 | /* Hash table of symbols which are being wrapped (the --wrap linker | |
457 | option). If this is NULL, no symbols are being wrapped. */ | |
458 | struct bfd_hash_table *wrap_hash; | |
459 | ||
460 | /* Hash table of symbols which may be left unresolved during | |
461 | a link. If this is NULL, no symbols can be left unresolved. */ | |
462 | struct bfd_hash_table *ignore_hash; | |
463 | ||
464 | /* The output BFD. */ | |
465 | bfd *output_bfd; | |
466 | ||
467 | /* The list of input BFD's involved in the link. These are chained | |
468 | together via the link_next field. */ | |
469 | bfd *input_bfds; | |
470 | bfd **input_bfds_tail; | |
471 | ||
472 | /* If a symbol should be created for each input BFD, this is section | |
473 | where those symbols should be placed. It must be a section in | |
474 | the output BFD. It may be NULL, in which case no such symbols | |
475 | will be created. This is to support CREATE_OBJECT_SYMBOLS in the | |
476 | linker command language. */ | |
477 | asection *create_object_symbols_section; | |
478 | ||
479 | /* List of global symbol names that are starting points for marking | |
480 | sections against garbage collection. */ | |
481 | struct bfd_sym_chain *gc_sym_list; | |
482 | ||
483 | /* If a base output file is wanted, then this points to it */ | |
484 | void *base_file; | |
485 | ||
486 | /* The function to call when the executable or shared object is | |
487 | loaded. */ | |
488 | const char *init_function; | |
489 | ||
490 | /* The function to call when the executable or shared object is | |
491 | unloaded. */ | |
492 | const char *fini_function; | |
493 | ||
494 | /* Number of relaxation passes. Usually only one relaxation pass | |
495 | is needed. But a backend can have as many relaxation passes as | |
496 | necessary. During bfd_relax_section call, it is set to the | |
497 | current pass, starting from 0. */ | |
498 | int relax_pass; | |
499 | ||
500 | /* Number of relaxation trips. This number is incremented every | |
501 | time the relaxation pass is restarted due to a previous | |
502 | relaxation returning true in *AGAIN. */ | |
503 | int relax_trip; | |
504 | ||
505 | /* Non-zero if auto-import thunks for DATA items in pei386 DLLs | |
506 | should be generated/linked against. Set to 1 if this feature | |
507 | is explicitly requested by the user, -1 if enabled by default. */ | |
508 | int pei386_auto_import; | |
509 | ||
510 | /* Non-zero if runtime relocs for DATA items with non-zero addends | |
511 | in pei386 DLLs should be generated. Set to 1 if this feature | |
512 | is explicitly requested by the user, -1 if enabled by default. */ | |
513 | int pei386_runtime_pseudo_reloc; | |
514 | ||
515 | /* How many spare .dynamic DT_NULL entries should be added? */ | |
516 | unsigned int spare_dynamic_tags; | |
517 | ||
518 | /* May be used to set DT_FLAGS for ELF. */ | |
519 | bfd_vma flags; | |
520 | ||
521 | /* May be used to set DT_FLAGS_1 for ELF. */ | |
522 | bfd_vma flags_1; | |
523 | ||
524 | /* Start and end of RELRO region. */ | |
525 | bfd_vma relro_start, relro_end; | |
526 | ||
527 | /* List of symbols should be dynamic. */ | |
528 | struct bfd_elf_dynamic_list *dynamic_list; | |
529 | ||
530 | /* The version information. */ | |
531 | struct bfd_elf_version_tree *version_info; | |
532 | }; | |
533 | ||
534 | /* This structures holds a set of callback functions. These are called | |
535 | by the BFD linker routines. Except for the info functions, the first | |
536 | argument to each callback function is the bfd_link_info structure | |
537 | being used and each function returns a boolean value. If the | |
538 | function returns FALSE, then the BFD function which called it should | |
539 | return with a failure indication. */ | |
540 | ||
541 | struct bfd_link_callbacks | |
542 | { | |
543 | /* A function which is called when an object is added from an | |
544 | archive. ABFD is the archive element being added. NAME is the | |
545 | name of the symbol which caused the archive element to be pulled | |
546 | in. This function may set *SUBSBFD to point to an alternative | |
547 | BFD from which symbols should in fact be added in place of the | |
548 | original BFD's symbols. */ | |
549 | bfd_boolean (*add_archive_element) | |
550 | (struct bfd_link_info *, bfd *abfd, const char *name, bfd **subsbfd); | |
551 | /* A function which is called when a symbol is found with multiple | |
552 | definitions. H is the symbol which is defined multiple times. | |
553 | NBFD is the new BFD, NSEC is the new section, and NVAL is the new | |
554 | value. NSEC may be bfd_com_section or bfd_ind_section. */ | |
555 | bfd_boolean (*multiple_definition) | |
556 | (struct bfd_link_info *, struct bfd_link_hash_entry *h, | |
557 | bfd *nbfd, asection *nsec, bfd_vma nval); | |
558 | /* A function which is called when a common symbol is defined | |
559 | multiple times. H is the symbol appearing multiple times. | |
560 | NBFD is the BFD of the new symbol. NTYPE is the type of the new | |
561 | symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or | |
562 | bfd_link_hash_indirect. If NTYPE is bfd_link_hash_common, NSIZE | |
563 | is the size of the new symbol. */ | |
564 | bfd_boolean (*multiple_common) | |
565 | (struct bfd_link_info *, struct bfd_link_hash_entry *h, | |
566 | bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize); | |
567 | /* A function which is called to add a symbol to a set. ENTRY is | |
568 | the link hash table entry for the set itself (e.g., | |
569 | __CTOR_LIST__). RELOC is the relocation to use for an entry in | |
570 | the set when generating a relocatable file, and is also used to | |
571 | get the size of the entry when generating an executable file. | |
572 | ABFD, SEC and VALUE identify the value to add to the set. */ | |
573 | bfd_boolean (*add_to_set) | |
574 | (struct bfd_link_info *, struct bfd_link_hash_entry *entry, | |
575 | bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value); | |
576 | /* A function which is called when the name of a g++ constructor or | |
577 | destructor is found. This is only called by some object file | |
578 | formats. CONSTRUCTOR is TRUE for a constructor, FALSE for a | |
579 | destructor. This will use BFD_RELOC_CTOR when generating a | |
580 | relocatable file. NAME is the name of the symbol found. ABFD, | |
581 | SECTION and VALUE are the value of the symbol. */ | |
582 | bfd_boolean (*constructor) | |
583 | (struct bfd_link_info *, bfd_boolean constructor, const char *name, | |
584 | bfd *abfd, asection *sec, bfd_vma value); | |
585 | /* A function which is called to issue a linker warning. For | |
586 | example, this is called when there is a reference to a warning | |
587 | symbol. WARNING is the warning to be issued. SYMBOL is the name | |
588 | of the symbol which triggered the warning; it may be NULL if | |
589 | there is none. ABFD, SECTION and ADDRESS identify the location | |
590 | which trigerred the warning; either ABFD or SECTION or both may | |
591 | be NULL if the location is not known. */ | |
592 | bfd_boolean (*warning) | |
593 | (struct bfd_link_info *, const char *warning, const char *symbol, | |
594 | bfd *abfd, asection *section, bfd_vma address); | |
595 | /* A function which is called when a relocation is attempted against | |
596 | an undefined symbol. NAME is the symbol which is undefined. | |
597 | ABFD, SECTION and ADDRESS identify the location from which the | |
598 | reference is made. IS_FATAL indicates whether an undefined symbol is | |
599 | a fatal error or not. In some cases SECTION may be NULL. */ | |
600 | bfd_boolean (*undefined_symbol) | |
601 | (struct bfd_link_info *, const char *name, bfd *abfd, | |
602 | asection *section, bfd_vma address, bfd_boolean is_fatal); | |
603 | /* A function which is called when a reloc overflow occurs. ENTRY is | |
604 | the link hash table entry for the symbol the reloc is against. | |
605 | NAME is the name of the local symbol or section the reloc is | |
606 | against, RELOC_NAME is the name of the relocation, and ADDEND is | |
607 | any addend that is used. ABFD, SECTION and ADDRESS identify the | |
608 | location at which the overflow occurs; if this is the result of a | |
609 | bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then | |
610 | ABFD will be NULL. */ | |
611 | bfd_boolean (*reloc_overflow) | |
612 | (struct bfd_link_info *, struct bfd_link_hash_entry *entry, | |
613 | const char *name, const char *reloc_name, bfd_vma addend, | |
614 | bfd *abfd, asection *section, bfd_vma address); | |
615 | /* A function which is called when a dangerous reloc is performed. | |
616 | MESSAGE is an appropriate message. | |
617 | ABFD, SECTION and ADDRESS identify the location at which the | |
618 | problem occurred; if this is the result of a | |
619 | bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then | |
620 | ABFD will be NULL. */ | |
621 | bfd_boolean (*reloc_dangerous) | |
622 | (struct bfd_link_info *, const char *message, | |
623 | bfd *abfd, asection *section, bfd_vma address); | |
624 | /* A function which is called when a reloc is found to be attached | |
625 | to a symbol which is not being written out. NAME is the name of | |
626 | the symbol. ABFD, SECTION and ADDRESS identify the location of | |
627 | the reloc; if this is the result of a | |
628 | bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then | |
629 | ABFD will be NULL. */ | |
630 | bfd_boolean (*unattached_reloc) | |
631 | (struct bfd_link_info *, const char *name, | |
632 | bfd *abfd, asection *section, bfd_vma address); | |
633 | /* A function which is called when a symbol in notice_hash is | |
634 | defined or referenced. H is the symbol. ABFD, SECTION and | |
635 | ADDRESS are the (new) value of the symbol. If SECTION is | |
636 | bfd_und_section, this is a reference. FLAGS are the symbol | |
637 | BSF_* flags. STRING is the name of the symbol to indirect to if | |
638 | the sym is indirect, or the warning string if a warning sym. */ | |
639 | bfd_boolean (*notice) | |
640 | (struct bfd_link_info *, struct bfd_link_hash_entry *h, | |
641 | bfd *abfd, asection *section, bfd_vma address, flagword flags, | |
642 | const char *string); | |
643 | /* Error or warning link info message. */ | |
644 | void (*einfo) | |
645 | (const char *fmt, ...); | |
646 | /* General link info message. */ | |
647 | void (*info) | |
648 | (const char *fmt, ...); | |
649 | /* Message to be printed in linker map file. */ | |
650 | void (*minfo) | |
651 | (const char *fmt, ...); | |
652 | /* This callback provides a chance for users of the BFD library to | |
653 | override its decision about whether to place two adjacent sections | |
654 | into the same segment. */ | |
655 | bfd_boolean (*override_segment_assignment) | |
656 | (struct bfd_link_info *, bfd * abfd, | |
657 | asection * current_section, asection * previous_section, | |
658 | bfd_boolean new_segment); | |
659 | }; | |
660 | \f | |
661 | /* The linker builds link_order structures which tell the code how to | |
662 | include input data in the output file. */ | |
663 | ||
664 | /* These are the types of link_order structures. */ | |
665 | ||
666 | enum bfd_link_order_type | |
667 | { | |
668 | bfd_undefined_link_order, /* Undefined. */ | |
669 | bfd_indirect_link_order, /* Built from a section. */ | |
670 | bfd_data_link_order, /* Set to explicit data. */ | |
671 | bfd_section_reloc_link_order, /* Relocate against a section. */ | |
672 | bfd_symbol_reloc_link_order /* Relocate against a symbol. */ | |
673 | }; | |
674 | ||
675 | /* This is the link_order structure itself. These form a chain | |
676 | attached to the output section whose contents they are describing. */ | |
677 | ||
678 | struct bfd_link_order | |
679 | { | |
680 | /* Next link_order in chain. */ | |
681 | struct bfd_link_order *next; | |
682 | /* Type of link_order. */ | |
683 | enum bfd_link_order_type type; | |
684 | /* Offset within output section. */ | |
685 | bfd_vma offset; | |
686 | /* Size within output section. */ | |
687 | bfd_size_type size; | |
688 | /* Type specific information. */ | |
689 | union | |
690 | { | |
691 | struct | |
692 | { | |
693 | /* Section to include. If this is used, then | |
694 | section->output_section must be the section the | |
695 | link_order is attached to, section->output_offset must | |
696 | equal the link_order offset field, and section->size | |
697 | must equal the link_order size field. Maybe these | |
698 | restrictions should be relaxed someday. */ | |
699 | asection *section; | |
700 | } indirect; | |
701 | struct | |
702 | { | |
703 | /* Size of contents, or zero when contents should be filled by | |
704 | the architecture-dependent fill function. | |
705 | A non-zero value allows filling of the output section | |
706 | with an arbitrary repeated pattern. */ | |
707 | unsigned int size; | |
708 | /* Data to put into file. */ | |
709 | bfd_byte *contents; | |
710 | } data; | |
711 | struct | |
712 | { | |
713 | /* Description of reloc to generate. Used for | |
714 | bfd_section_reloc_link_order and | |
715 | bfd_symbol_reloc_link_order. */ | |
716 | struct bfd_link_order_reloc *p; | |
717 | } reloc; | |
718 | } u; | |
719 | }; | |
720 | ||
721 | /* A linker order of type bfd_section_reloc_link_order or | |
722 | bfd_symbol_reloc_link_order means to create a reloc against a | |
723 | section or symbol, respectively. This is used to implement -Ur to | |
724 | generate relocs for the constructor tables. The | |
725 | bfd_link_order_reloc structure describes the reloc that BFD should | |
726 | create. It is similar to a arelent, but I didn't use arelent | |
727 | because the linker does not know anything about most symbols, and | |
728 | any asymbol structure it creates will be partially meaningless. | |
729 | This information could logically be in the bfd_link_order struct, | |
730 | but I didn't want to waste the space since these types of relocs | |
731 | are relatively rare. */ | |
732 | ||
733 | struct bfd_link_order_reloc | |
734 | { | |
735 | /* Reloc type. */ | |
736 | bfd_reloc_code_real_type reloc; | |
737 | ||
738 | union | |
739 | { | |
740 | /* For type bfd_section_reloc_link_order, this is the section | |
741 | the reloc should be against. This must be a section in the | |
742 | output BFD, not any of the input BFDs. */ | |
743 | asection *section; | |
744 | /* For type bfd_symbol_reloc_link_order, this is the name of the | |
745 | symbol the reloc should be against. */ | |
746 | const char *name; | |
747 | } u; | |
748 | ||
749 | /* Addend to use. The object file should contain zero. The BFD | |
750 | backend is responsible for filling in the contents of the object | |
751 | file correctly. For some object file formats (e.g., COFF) the | |
752 | addend must be stored into in the object file, and for some | |
753 | (e.g., SPARC a.out) it is kept in the reloc. */ | |
754 | bfd_vma addend; | |
755 | }; | |
756 | ||
757 | /* Allocate a new link_order for a section. */ | |
758 | extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *); | |
759 | ||
760 | /* These structures are used to describe version information for the | |
761 | ELF linker. These structures could be manipulated entirely inside | |
762 | BFD, but it would be a pain. Instead, the regular linker sets up | |
763 | these structures, and then passes them into BFD. */ | |
764 | ||
765 | /* Glob pattern for a version. */ | |
766 | ||
767 | struct bfd_elf_version_expr | |
768 | { | |
769 | /* Next glob pattern for this version. */ | |
770 | struct bfd_elf_version_expr *next; | |
771 | /* Glob pattern. */ | |
772 | const char *pattern; | |
773 | /* Set if pattern is not a glob. */ | |
774 | unsigned int literal : 1; | |
775 | /* Defined by ".symver". */ | |
776 | unsigned int symver : 1; | |
777 | /* Defined by version script. */ | |
778 | unsigned int script : 1; | |
779 | /* Pattern type. */ | |
780 | #define BFD_ELF_VERSION_C_TYPE 1 | |
781 | #define BFD_ELF_VERSION_CXX_TYPE 2 | |
782 | #define BFD_ELF_VERSION_JAVA_TYPE 4 | |
783 | unsigned int mask : 3; | |
784 | }; | |
785 | ||
786 | struct bfd_elf_version_expr_head | |
787 | { | |
788 | /* List of all patterns, both wildcards and non-wildcards. */ | |
789 | struct bfd_elf_version_expr *list; | |
790 | /* Hash table for non-wildcards. */ | |
791 | void *htab; | |
792 | /* Remaining patterns. */ | |
793 | struct bfd_elf_version_expr *remaining; | |
794 | /* What kind of pattern types are present in list (bitmask). */ | |
795 | unsigned int mask; | |
796 | }; | |
797 | ||
798 | /* Version dependencies. */ | |
799 | ||
800 | struct bfd_elf_version_deps | |
801 | { | |
802 | /* Next dependency for this version. */ | |
803 | struct bfd_elf_version_deps *next; | |
804 | /* The version which this version depends upon. */ | |
805 | struct bfd_elf_version_tree *version_needed; | |
806 | }; | |
807 | ||
808 | /* A node in the version tree. */ | |
809 | ||
810 | struct bfd_elf_version_tree | |
811 | { | |
812 | /* Next version. */ | |
813 | struct bfd_elf_version_tree *next; | |
814 | /* Name of this version. */ | |
815 | const char *name; | |
816 | /* Version number. */ | |
817 | unsigned int vernum; | |
818 | /* Regular expressions for global symbols in this version. */ | |
819 | struct bfd_elf_version_expr_head globals; | |
820 | /* Regular expressions for local symbols in this version. */ | |
821 | struct bfd_elf_version_expr_head locals; | |
822 | /* List of versions which this version depends upon. */ | |
823 | struct bfd_elf_version_deps *deps; | |
824 | /* Index of the version name. This is used within BFD. */ | |
825 | unsigned int name_indx; | |
826 | /* Whether this version tree was used. This is used within BFD. */ | |
827 | int used; | |
828 | /* Matching hook. */ | |
829 | struct bfd_elf_version_expr *(*match) | |
830 | (struct bfd_elf_version_expr_head *head, | |
831 | struct bfd_elf_version_expr *prev, const char *sym); | |
832 | }; | |
833 | ||
834 | struct bfd_elf_dynamic_list | |
835 | { | |
836 | struct bfd_elf_version_expr_head head; | |
837 | struct bfd_elf_version_expr *(*match) | |
838 | (struct bfd_elf_version_expr_head *head, | |
839 | struct bfd_elf_version_expr *prev, const char *sym); | |
840 | }; | |
841 | ||
842 | #endif |