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1 227 jeremybenn
@section Targets
2
 
3
 
4
@strong{Description}@*
5
Each port of BFD to a different machine requires the creation
6
of a target back end. All the back end provides to the root
7
part of BFD is a structure containing pointers to functions
8
which perform certain low level operations on files. BFD
9
translates the applications's requests through a pointer into
10
calls to the back end routines.
11
 
12
When a file is opened with @code{bfd_openr}, its format and
13
target are unknown. BFD uses various mechanisms to determine
14
how to interpret the file. The operations performed are:
15
 
16
@itemize @bullet
17
 
18
@item
19
Create a BFD by calling the internal routine
20
@code{_bfd_new_bfd}, then call @code{bfd_find_target} with the
21
target string supplied to @code{bfd_openr} and the new BFD pointer.
22
 
23
@item
24
If a null target string was provided to @code{bfd_find_target},
25
look up the environment variable @code{GNUTARGET} and use
26
that as the target string.
27
 
28
@item
29
If the target string is still @code{NULL}, or the target string is
30
@code{default}, then use the first item in the target vector
31
as the target type, and set @code{target_defaulted} in the BFD to
32
cause @code{bfd_check_format} to loop through all the targets.
33
@xref{bfd_target}.  @xref{Formats}.
34
 
35
@item
36
Otherwise, inspect the elements in the target vector
37
one by one, until a match on target name is found. When found,
38
use it.
39
 
40
@item
41
Otherwise return the error @code{bfd_error_invalid_target} to
42
@code{bfd_openr}.
43
 
44
@item
45
@code{bfd_openr} attempts to open the file using
46
@code{bfd_open_file}, and returns the BFD.
47
@end itemize
48
Once the BFD has been opened and the target selected, the file
49
format may be determined. This is done by calling
50
@code{bfd_check_format} on the BFD with a suggested format.
51
If @code{target_defaulted} has been set, each possible target
52
type is tried to see if it recognizes the specified format.
53
@code{bfd_check_format} returns @code{TRUE} when the caller guesses right.
54
@menu
55
* bfd_target::
56
@end menu
57
 
58
@node bfd_target,  , Targets, Targets
59
 
60
@subsection bfd_target
61
 
62
 
63
@strong{Description}@*
64
This structure contains everything that BFD knows about a
65
target. It includes things like its byte order, name, and which
66
routines to call to do various operations.
67
 
68
Every BFD points to a target structure with its @code{xvec}
69
member.
70
 
71
The macros below are used to dispatch to functions through the
72
@code{bfd_target} vector. They are used in a number of macros further
73
down in @file{bfd.h}, and are also used when calling various
74
routines by hand inside the BFD implementation.  The @var{arglist}
75
argument must be parenthesized; it contains all the arguments
76
to the called function.
77
 
78
They make the documentation (more) unpleasant to read, so if
79
someone wants to fix this and not break the above, please do.
80
@example
81
#define BFD_SEND(bfd, message, arglist) \
82
  ((*((bfd)->xvec->message)) arglist)
83
 
84
#ifdef DEBUG_BFD_SEND
85
#undef BFD_SEND
86
#define BFD_SEND(bfd, message, arglist) \
87
  (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \
88
    ((*((bfd)->xvec->message)) arglist) : \
89
    (bfd_assert (__FILE__,__LINE__), NULL))
90
#endif
91
@end example
92
For operations which index on the BFD format:
93
@example
94
#define BFD_SEND_FMT(bfd, message, arglist) \
95
  (((bfd)->xvec->message[(int) ((bfd)->format)]) arglist)
96
 
97
#ifdef DEBUG_BFD_SEND
98
#undef BFD_SEND_FMT
99
#define BFD_SEND_FMT(bfd, message, arglist) \
100
  (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \
101
   (((bfd)->xvec->message[(int) ((bfd)->format)]) arglist) : \
102
   (bfd_assert (__FILE__,__LINE__), NULL))
103
#endif
104
 
105
@end example
106
This is the structure which defines the type of BFD this is.  The
107
@code{xvec} member of the struct @code{bfd} itself points here.  Each
108
module that implements access to a different target under BFD,
109
defines one of these.
110
 
111
FIXME, these names should be rationalised with the names of
112
the entry points which call them. Too bad we can't have one
113
macro to define them both!
114
@example
115
enum bfd_flavour
116
@{
117
  bfd_target_unknown_flavour,
118
  bfd_target_aout_flavour,
119
  bfd_target_coff_flavour,
120
  bfd_target_ecoff_flavour,
121
  bfd_target_xcoff_flavour,
122
  bfd_target_elf_flavour,
123
  bfd_target_ieee_flavour,
124
  bfd_target_nlm_flavour,
125
  bfd_target_oasys_flavour,
126
  bfd_target_tekhex_flavour,
127
  bfd_target_srec_flavour,
128
  bfd_target_verilog_flavour,
129
  bfd_target_ihex_flavour,
130
  bfd_target_som_flavour,
131
  bfd_target_os9k_flavour,
132
  bfd_target_versados_flavour,
133
  bfd_target_msdos_flavour,
134
  bfd_target_ovax_flavour,
135
  bfd_target_evax_flavour,
136
  bfd_target_mmo_flavour,
137
  bfd_target_mach_o_flavour,
138
  bfd_target_pef_flavour,
139
  bfd_target_pef_xlib_flavour,
140
  bfd_target_sym_flavour
141
@};
142
 
143
enum bfd_endian @{ BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN @};
144
 
145
/* Forward declaration.  */
146
typedef struct bfd_link_info _bfd_link_info;
147
 
148
typedef struct bfd_target
149
@{
150
  /* Identifies the kind of target, e.g., SunOS4, Ultrix, etc.  */
151
  char *name;
152
 
153
 /* The "flavour" of a back end is a general indication about
154
    the contents of a file.  */
155
  enum bfd_flavour flavour;
156
 
157
  /* The order of bytes within the data area of a file.  */
158
  enum bfd_endian byteorder;
159
 
160
 /* The order of bytes within the header parts of a file.  */
161
  enum bfd_endian header_byteorder;
162
 
163
  /* A mask of all the flags which an executable may have set -
164
     from the set @code{BFD_NO_FLAGS}, @code{HAS_RELOC}, ...@code{D_PAGED}.  */
165
  flagword object_flags;
166
 
167
 /* A mask of all the flags which a section may have set - from
168
    the set @code{SEC_NO_FLAGS}, @code{SEC_ALLOC}, ...@code{SET_NEVER_LOAD}.  */
169
  flagword section_flags;
170
 
171
 /* The character normally found at the front of a symbol.
172
    (if any), perhaps `_'.  */
173
  char symbol_leading_char;
174
 
175
 /* The pad character for file names within an archive header.  */
176
  char ar_pad_char;
177
 
178
  /* The maximum number of characters in an archive header.  */
179
  unsigned short ar_max_namelen;
180
 
181
  /* Entries for byte swapping for data. These are different from the
182
     other entry points, since they don't take a BFD as the first argument.
183
     Certain other handlers could do the same.  */
184
  bfd_uint64_t   (*bfd_getx64) (const void *);
185
  bfd_int64_t    (*bfd_getx_signed_64) (const void *);
186
  void           (*bfd_putx64) (bfd_uint64_t, void *);
187
  bfd_vma        (*bfd_getx32) (const void *);
188
  bfd_signed_vma (*bfd_getx_signed_32) (const void *);
189
  void           (*bfd_putx32) (bfd_vma, void *);
190
  bfd_vma        (*bfd_getx16) (const void *);
191
  bfd_signed_vma (*bfd_getx_signed_16) (const void *);
192
  void           (*bfd_putx16) (bfd_vma, void *);
193
 
194
  /* Byte swapping for the headers.  */
195
  bfd_uint64_t   (*bfd_h_getx64) (const void *);
196
  bfd_int64_t    (*bfd_h_getx_signed_64) (const void *);
197
  void           (*bfd_h_putx64) (bfd_uint64_t, void *);
198
  bfd_vma        (*bfd_h_getx32) (const void *);
199
  bfd_signed_vma (*bfd_h_getx_signed_32) (const void *);
200
  void           (*bfd_h_putx32) (bfd_vma, void *);
201
  bfd_vma        (*bfd_h_getx16) (const void *);
202
  bfd_signed_vma (*bfd_h_getx_signed_16) (const void *);
203
  void           (*bfd_h_putx16) (bfd_vma, void *);
204
 
205
  /* Format dependent routines: these are vectors of entry points
206
     within the target vector structure, one for each format to check.  */
207
 
208
  /* Check the format of a file being read.  Return a @code{bfd_target *} or zero.  */
209
  const struct bfd_target *(*_bfd_check_format[bfd_type_end]) (bfd *);
210
 
211
  /* Set the format of a file being written.  */
212
  bfd_boolean (*_bfd_set_format[bfd_type_end]) (bfd *);
213
 
214
  /* Write cached information into a file being written, at @code{bfd_close}.  */
215
  bfd_boolean (*_bfd_write_contents[bfd_type_end]) (bfd *);
216
 
217
@end example
218
The general target vector.  These vectors are initialized using the
219
BFD_JUMP_TABLE macros.
220
@example
221
 
222
  /* Generic entry points.  */
223
#define BFD_JUMP_TABLE_GENERIC(NAME) \
224
  NAME##_close_and_cleanup, \
225
  NAME##_bfd_free_cached_info, \
226
  NAME##_new_section_hook, \
227
  NAME##_get_section_contents, \
228
  NAME##_get_section_contents_in_window
229
 
230
  /* Called when the BFD is being closed to do any necessary cleanup.  */
231
  bfd_boolean (*_close_and_cleanup) (bfd *);
232
  /* Ask the BFD to free all cached information.  */
233
  bfd_boolean (*_bfd_free_cached_info) (bfd *);
234
  /* Called when a new section is created.  */
235
  bfd_boolean (*_new_section_hook) (bfd *, sec_ptr);
236
  /* Read the contents of a section.  */
237
  bfd_boolean (*_bfd_get_section_contents)
238
    (bfd *, sec_ptr, void *, file_ptr, bfd_size_type);
239
  bfd_boolean (*_bfd_get_section_contents_in_window)
240
    (bfd *, sec_ptr, bfd_window *, file_ptr, bfd_size_type);
241
 
242
  /* Entry points to copy private data.  */
243
#define BFD_JUMP_TABLE_COPY(NAME) \
244
  NAME##_bfd_copy_private_bfd_data, \
245
  NAME##_bfd_merge_private_bfd_data, \
246
  _bfd_generic_init_private_section_data, \
247
  NAME##_bfd_copy_private_section_data, \
248
  NAME##_bfd_copy_private_symbol_data, \
249
  NAME##_bfd_copy_private_header_data, \
250
  NAME##_bfd_set_private_flags, \
251
  NAME##_bfd_print_private_bfd_data
252
 
253
  /* Called to copy BFD general private data from one object file
254
     to another.  */
255
  bfd_boolean (*_bfd_copy_private_bfd_data) (bfd *, bfd *);
256
  /* Called to merge BFD general private data from one object file
257
     to a common output file when linking.  */
258
  bfd_boolean (*_bfd_merge_private_bfd_data) (bfd *, bfd *);
259
  /* Called to initialize BFD private section data from one object file
260
     to another.  */
261
#define bfd_init_private_section_data(ibfd, isec, obfd, osec, link_info) \
262
  BFD_SEND (obfd, _bfd_init_private_section_data, (ibfd, isec, obfd, osec, link_info))
263
  bfd_boolean (*_bfd_init_private_section_data)
264
    (bfd *, sec_ptr, bfd *, sec_ptr, struct bfd_link_info *);
265
  /* Called to copy BFD private section data from one object file
266
     to another.  */
267
  bfd_boolean (*_bfd_copy_private_section_data)
268
    (bfd *, sec_ptr, bfd *, sec_ptr);
269
  /* Called to copy BFD private symbol data from one symbol
270
     to another.  */
271
  bfd_boolean (*_bfd_copy_private_symbol_data)
272
    (bfd *, asymbol *, bfd *, asymbol *);
273
  /* Called to copy BFD private header data from one object file
274
     to another.  */
275
  bfd_boolean (*_bfd_copy_private_header_data)
276
    (bfd *, bfd *);
277
  /* Called to set private backend flags.  */
278
  bfd_boolean (*_bfd_set_private_flags) (bfd *, flagword);
279
 
280
  /* Called to print private BFD data.  */
281
  bfd_boolean (*_bfd_print_private_bfd_data) (bfd *, void *);
282
 
283
  /* Core file entry points.  */
284
#define BFD_JUMP_TABLE_CORE(NAME) \
285
  NAME##_core_file_failing_command, \
286
  NAME##_core_file_failing_signal, \
287
  NAME##_core_file_matches_executable_p
288
 
289
  char *      (*_core_file_failing_command) (bfd *);
290
  int         (*_core_file_failing_signal) (bfd *);
291
  bfd_boolean (*_core_file_matches_executable_p) (bfd *, bfd *);
292
 
293
  /* Archive entry points.  */
294
#define BFD_JUMP_TABLE_ARCHIVE(NAME) \
295
  NAME##_slurp_armap, \
296
  NAME##_slurp_extended_name_table, \
297
  NAME##_construct_extended_name_table, \
298
  NAME##_truncate_arname, \
299
  NAME##_write_armap, \
300
  NAME##_read_ar_hdr, \
301
  NAME##_write_ar_hdr, \
302
  NAME##_openr_next_archived_file, \
303
  NAME##_get_elt_at_index, \
304
  NAME##_generic_stat_arch_elt, \
305
  NAME##_update_armap_timestamp
306
 
307
  bfd_boolean (*_bfd_slurp_armap) (bfd *);
308
  bfd_boolean (*_bfd_slurp_extended_name_table) (bfd *);
309
  bfd_boolean (*_bfd_construct_extended_name_table)
310
    (bfd *, char **, bfd_size_type *, const char **);
311
  void        (*_bfd_truncate_arname) (bfd *, const char *, char *);
312
  bfd_boolean (*write_armap)
313
    (bfd *, unsigned int, struct orl *, unsigned int, int);
314
  void *      (*_bfd_read_ar_hdr_fn) (bfd *);
315
  bfd_boolean (*_bfd_write_ar_hdr_fn) (bfd *, bfd *);
316
  bfd *       (*openr_next_archived_file) (bfd *, bfd *);
317
#define bfd_get_elt_at_index(b,i) BFD_SEND (b, _bfd_get_elt_at_index, (b,i))
318
  bfd *       (*_bfd_get_elt_at_index) (bfd *, symindex);
319
  int         (*_bfd_stat_arch_elt) (bfd *, struct stat *);
320
  bfd_boolean (*_bfd_update_armap_timestamp) (bfd *);
321
 
322
  /* Entry points used for symbols.  */
323
#define BFD_JUMP_TABLE_SYMBOLS(NAME) \
324
  NAME##_get_symtab_upper_bound, \
325
  NAME##_canonicalize_symtab, \
326
  NAME##_make_empty_symbol, \
327
  NAME##_print_symbol, \
328
  NAME##_get_symbol_info, \
329
  NAME##_bfd_is_local_label_name, \
330
  NAME##_bfd_is_target_special_symbol, \
331
  NAME##_get_lineno, \
332
  NAME##_find_nearest_line, \
333
  _bfd_generic_find_line, \
334
  NAME##_find_inliner_info, \
335
  NAME##_bfd_make_debug_symbol, \
336
  NAME##_read_minisymbols, \
337
  NAME##_minisymbol_to_symbol
338
 
339
  long        (*_bfd_get_symtab_upper_bound) (bfd *);
340
  long        (*_bfd_canonicalize_symtab)
341
    (bfd *, struct bfd_symbol **);
342
  struct bfd_symbol *
343
              (*_bfd_make_empty_symbol) (bfd *);
344
  void        (*_bfd_print_symbol)
345
    (bfd *, void *, struct bfd_symbol *, bfd_print_symbol_type);
346
#define bfd_print_symbol(b,p,s,e) BFD_SEND (b, _bfd_print_symbol, (b,p,s,e))
347
  void        (*_bfd_get_symbol_info)
348
    (bfd *, struct bfd_symbol *, symbol_info *);
349
#define bfd_get_symbol_info(b,p,e) BFD_SEND (b, _bfd_get_symbol_info, (b,p,e))
350
  bfd_boolean (*_bfd_is_local_label_name) (bfd *, const char *);
351
  bfd_boolean (*_bfd_is_target_special_symbol) (bfd *, asymbol *);
352
  alent *     (*_get_lineno) (bfd *, struct bfd_symbol *);
353
  bfd_boolean (*_bfd_find_nearest_line)
354
    (bfd *, struct bfd_section *, struct bfd_symbol **, bfd_vma,
355
     const char **, const char **, unsigned int *);
356
  bfd_boolean (*_bfd_find_line)
357
    (bfd *, struct bfd_symbol **, struct bfd_symbol *,
358
     const char **, unsigned int *);
359
  bfd_boolean (*_bfd_find_inliner_info)
360
    (bfd *, const char **, const char **, unsigned int *);
361
 /* Back-door to allow format-aware applications to create debug symbols
362
    while using BFD for everything else.  Currently used by the assembler
363
    when creating COFF files.  */
364
  asymbol *   (*_bfd_make_debug_symbol)
365
    (bfd *, void *, unsigned long size);
366
#define bfd_read_minisymbols(b, d, m, s) \
367
  BFD_SEND (b, _read_minisymbols, (b, d, m, s))
368
  long        (*_read_minisymbols)
369
    (bfd *, bfd_boolean, void **, unsigned int *);
370
#define bfd_minisymbol_to_symbol(b, d, m, f) \
371
  BFD_SEND (b, _minisymbol_to_symbol, (b, d, m, f))
372
  asymbol *   (*_minisymbol_to_symbol)
373
    (bfd *, bfd_boolean, const void *, asymbol *);
374
 
375
  /* Routines for relocs.  */
376
#define BFD_JUMP_TABLE_RELOCS(NAME) \
377
  NAME##_get_reloc_upper_bound, \
378
  NAME##_canonicalize_reloc, \
379
  NAME##_bfd_reloc_type_lookup, \
380
  NAME##_bfd_reloc_name_lookup
381
 
382
  long        (*_get_reloc_upper_bound) (bfd *, sec_ptr);
383
  long        (*_bfd_canonicalize_reloc)
384
    (bfd *, sec_ptr, arelent **, struct bfd_symbol **);
385
  /* See documentation on reloc types.  */
386
  reloc_howto_type *
387
              (*reloc_type_lookup) (bfd *, bfd_reloc_code_real_type);
388
  reloc_howto_type *
389
              (*reloc_name_lookup) (bfd *, const char *);
390
 
391
 
392
  /* Routines used when writing an object file.  */
393
#define BFD_JUMP_TABLE_WRITE(NAME) \
394
  NAME##_set_arch_mach, \
395
  NAME##_set_section_contents
396
 
397
  bfd_boolean (*_bfd_set_arch_mach)
398
    (bfd *, enum bfd_architecture, unsigned long);
399
  bfd_boolean (*_bfd_set_section_contents)
400
    (bfd *, sec_ptr, const void *, file_ptr, bfd_size_type);
401
 
402
  /* Routines used by the linker.  */
403
#define BFD_JUMP_TABLE_LINK(NAME) \
404
  NAME##_sizeof_headers, \
405
  NAME##_bfd_get_relocated_section_contents, \
406
  NAME##_bfd_relax_section, \
407
  NAME##_bfd_link_hash_table_create, \
408
  NAME##_bfd_link_hash_table_free, \
409
  NAME##_bfd_link_add_symbols, \
410
  NAME##_bfd_link_just_syms, \
411
  NAME##_bfd_copy_link_hash_symbol_type, \
412
  NAME##_bfd_final_link, \
413
  NAME##_bfd_link_split_section, \
414
  NAME##_bfd_gc_sections, \
415
  NAME##_bfd_merge_sections, \
416
  NAME##_bfd_is_group_section, \
417
  NAME##_bfd_discard_group, \
418
  NAME##_section_already_linked, \
419
  NAME##_bfd_define_common_symbol
420
 
421
  int         (*_bfd_sizeof_headers) (bfd *, struct bfd_link_info *);
422
  bfd_byte *  (*_bfd_get_relocated_section_contents)
423
    (bfd *, struct bfd_link_info *, struct bfd_link_order *,
424
     bfd_byte *, bfd_boolean, struct bfd_symbol **);
425
 
426
  bfd_boolean (*_bfd_relax_section)
427
    (bfd *, struct bfd_section *, struct bfd_link_info *, bfd_boolean *);
428
 
429
  /* Create a hash table for the linker.  Different backends store
430
     different information in this table.  */
431
  struct bfd_link_hash_table *
432
              (*_bfd_link_hash_table_create) (bfd *);
433
 
434
  /* Release the memory associated with the linker hash table.  */
435
  void        (*_bfd_link_hash_table_free) (struct bfd_link_hash_table *);
436
 
437
  /* Add symbols from this object file into the hash table.  */
438
  bfd_boolean (*_bfd_link_add_symbols) (bfd *, struct bfd_link_info *);
439
 
440
  /* Indicate that we are only retrieving symbol values from this section.  */
441
  void        (*_bfd_link_just_syms) (asection *, struct bfd_link_info *);
442
 
443
  /* Copy the symbol type of a linker hash table entry.  */
444
#define bfd_copy_link_hash_symbol_type(b, t, f) \
445
  BFD_SEND (b, _bfd_copy_link_hash_symbol_type, (b, t, f))
446
  void (*_bfd_copy_link_hash_symbol_type)
447
    (bfd *, struct bfd_link_hash_entry *, struct bfd_link_hash_entry *);
448
 
449
  /* Do a link based on the link_order structures attached to each
450
     section of the BFD.  */
451
  bfd_boolean (*_bfd_final_link) (bfd *, struct bfd_link_info *);
452
 
453
  /* Should this section be split up into smaller pieces during linking.  */
454
  bfd_boolean (*_bfd_link_split_section) (bfd *, struct bfd_section *);
455
 
456
  /* Remove sections that are not referenced from the output.  */
457
  bfd_boolean (*_bfd_gc_sections) (bfd *, struct bfd_link_info *);
458
 
459
  /* Attempt to merge SEC_MERGE sections.  */
460
  bfd_boolean (*_bfd_merge_sections) (bfd *, struct bfd_link_info *);
461
 
462
  /* Is this section a member of a group?  */
463
  bfd_boolean (*_bfd_is_group_section) (bfd *, const struct bfd_section *);
464
 
465
  /* Discard members of a group.  */
466
  bfd_boolean (*_bfd_discard_group) (bfd *, struct bfd_section *);
467
 
468
  /* Check if SEC has been already linked during a reloceatable or
469
     final link.  */
470
  void (*_section_already_linked) (bfd *, struct bfd_section *,
471
                                   struct bfd_link_info *);
472
 
473
  /* Define a common symbol.  */
474
  bfd_boolean (*_bfd_define_common_symbol) (bfd *, struct bfd_link_info *,
475
                                            struct bfd_link_hash_entry *);
476
 
477
  /* Routines to handle dynamic symbols and relocs.  */
478
#define BFD_JUMP_TABLE_DYNAMIC(NAME) \
479
  NAME##_get_dynamic_symtab_upper_bound, \
480
  NAME##_canonicalize_dynamic_symtab, \
481
  NAME##_get_synthetic_symtab, \
482
  NAME##_get_dynamic_reloc_upper_bound, \
483
  NAME##_canonicalize_dynamic_reloc
484
 
485
  /* Get the amount of memory required to hold the dynamic symbols.  */
486
  long        (*_bfd_get_dynamic_symtab_upper_bound) (bfd *);
487
  /* Read in the dynamic symbols.  */
488
  long        (*_bfd_canonicalize_dynamic_symtab)
489
    (bfd *, struct bfd_symbol **);
490
  /* Create synthetized symbols.  */
491
  long        (*_bfd_get_synthetic_symtab)
492
    (bfd *, long, struct bfd_symbol **, long, struct bfd_symbol **,
493
     struct bfd_symbol **);
494
  /* Get the amount of memory required to hold the dynamic relocs.  */
495
  long        (*_bfd_get_dynamic_reloc_upper_bound) (bfd *);
496
  /* Read in the dynamic relocs.  */
497
  long        (*_bfd_canonicalize_dynamic_reloc)
498
    (bfd *, arelent **, struct bfd_symbol **);
499
 
500
@end example
501
A pointer to an alternative bfd_target in case the current one is not
502
satisfactory.  This can happen when the target cpu supports both big
503
and little endian code, and target chosen by the linker has the wrong
504
endianness.  The function open_output() in ld/ldlang.c uses this field
505
to find an alternative output format that is suitable.
506
@example
507
  /* Opposite endian version of this target.  */
508
  const struct bfd_target * alternative_target;
509
 
510
  /* Data for use by back-end routines, which isn't
511
     generic enough to belong in this structure.  */
512
  const void *backend_data;
513
 
514
@} bfd_target;
515
 
516
@end example
517
 
518
@findex bfd_set_default_target
519
@subsubsection @code{bfd_set_default_target}
520
@strong{Synopsis}
521
@example
522
bfd_boolean bfd_set_default_target (const char *name);
523
@end example
524
@strong{Description}@*
525
Set the default target vector to use when recognizing a BFD.
526
This takes the name of the target, which may be a BFD target
527
name or a configuration triplet.
528
 
529
@findex bfd_find_target
530
@subsubsection @code{bfd_find_target}
531
@strong{Synopsis}
532
@example
533
const bfd_target *bfd_find_target (const char *target_name, bfd *abfd);
534
@end example
535
@strong{Description}@*
536
Return a pointer to the transfer vector for the object target
537
named @var{target_name}.  If @var{target_name} is @code{NULL},
538
choose the one in the environment variable @code{GNUTARGET}; if
539
that is null or not defined, then choose the first entry in the
540
target list.  Passing in the string "default" or setting the
541
environment variable to "default" will cause the first entry in
542
the target list to be returned, and "target_defaulted" will be
543
set in the BFD if @var{abfd} isn't @code{NULL}.  This causes
544
@code{bfd_check_format} to loop over all the targets to find the
545
one that matches the file being read.
546
 
547
@findex bfd_get_target_info
548
@subsubsection @code{bfd_get_target_info}
549
@strong{Synopsis}
550
@example
551
const bfd_target *bfd_get_target_info (const char *target_name,
552
    bfd *abfd,
553
    bfd_boolean *is_bigendian,
554
    int *underscoring,
555
    const char **def_target_arch);
556
@end example
557
@strong{Description}@*
558
Return a pointer to the transfer vector for the object target
559
named @var{target_name}.  If @var{target_name} is @code{NULL},
560
choose the one in the environment variable @code{GNUTARGET}; if
561
that is null or not defined, then choose the first entry in the
562
target list.  Passing in the string "default" or setting the
563
environment variable to "default" will cause the first entry in
564
the target list to be returned, and "target_defaulted" will be
565
set in the BFD if @var{abfd} isn't @code{NULL}.  This causes
566
@code{bfd_check_format} to loop over all the targets to find the
567
one that matches the file being read.
568
If @var{is_bigendian} is not @code{NULL}, then set this value to target's
569
endian mode. True for big-endian, FALSE for little-endian or for
570
invalid target.
571
If @var{underscoring} is not @code{NULL}, then set this value to target's
572
underscoring mode. Zero for none-underscoring, -1 for invalid target,
573
else the value of target vector's symbol underscoring.
574
If @var{def_target_arch} is not @code{NULL}, then set it to the architecture
575
string specified by the target_name.
576
 
577
@findex bfd_target_list
578
@subsubsection @code{bfd_target_list}
579
@strong{Synopsis}
580
@example
581
const char ** bfd_target_list (void);
582
@end example
583
@strong{Description}@*
584
Return a freshly malloced NULL-terminated
585
vector of the names of all the valid BFD targets. Do not
586
modify the names.
587
 
588
@findex bfd_seach_for_target
589
@subsubsection @code{bfd_seach_for_target}
590
@strong{Synopsis}
591
@example
592
const bfd_target *bfd_search_for_target
593
   (int (*search_func) (const bfd_target *, void *),
594
    void *);
595
@end example
596
@strong{Description}@*
597
Return a pointer to the first transfer vector in the list of
598
transfer vectors maintained by BFD that produces a non-zero
599
result when passed to the function @var{search_func}.  The
600
parameter @var{data} is passed, unexamined, to the search
601
function.
602
 

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