aboutsummaryrefslogtreecommitdiff
path: root/gdb/arch-utils.c
blob: ecdecaf9a1a2bd46b2c84ca310d830106bc161a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
/* Dynamic architecture support for GDB, the GNU debugger.

   Copyright 1998, 1999, 2000, 2001, 2002 Free Software Foundation,
   Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"

#if GDB_MULTI_ARCH
#include "arch-utils.h"
#include "gdbcmd.h"
#include "inferior.h"		/* enum CALL_DUMMY_LOCATION et.al. */
#else
/* Just include everything in sight so that the every old definition
   of macro is visible. */
#include "symtab.h"
#include "frame.h"
#include "inferior.h"
#include "breakpoint.h"
#include "gdb_wait.h"
#include "gdbcore.h"
#include "gdbcmd.h"
#include "target.h"
#include "annotate.h"
#endif
#include "gdb_string.h"
#include "regcache.h"
#include "gdb_assert.h"
#include "sim-regno.h"

#include "version.h"

#include "floatformat.h"

/* Use the program counter to determine the contents and size
   of a breakpoint instruction.  If no target-dependent macro
   BREAKPOINT_FROM_PC has been defined to implement this function,
   assume that the breakpoint doesn't depend on the PC, and
   use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros.
   Return a pointer to a string of bytes that encode a breakpoint
   instruction, stores the length of the string to *lenptr,
   and optionally adjust the pc to point to the correct memory location
   for inserting the breakpoint.  */

const unsigned char *
legacy_breakpoint_from_pc (CORE_ADDR * pcptr, int *lenptr)
{
  /* {BIG_,LITTLE_}BREAKPOINT is the sequence of bytes we insert for a
     breakpoint.  On some machines, breakpoints are handled by the
     target environment and we don't have to worry about them here.  */
#ifdef BIG_BREAKPOINT
  if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
    {
      static unsigned char big_break_insn[] = BIG_BREAKPOINT;
      *lenptr = sizeof (big_break_insn);
      return big_break_insn;
    }
#endif
#ifdef LITTLE_BREAKPOINT
  if (TARGET_BYTE_ORDER != BFD_ENDIAN_BIG)
    {
      static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
      *lenptr = sizeof (little_break_insn);
      return little_break_insn;
    }
#endif
#ifdef BREAKPOINT
  {
    static unsigned char break_insn[] = BREAKPOINT;
    *lenptr = sizeof (break_insn);
    return break_insn;
  }
#endif
  *lenptr = 0;
  return NULL;
}

/* Implementation of extract return value that grubs around in the
   register cache.  */
void
legacy_extract_return_value (struct type *type, struct regcache *regcache,
			     void *valbuf)
{
  char *registers = deprecated_grub_regcache_for_registers (regcache);
  bfd_byte *buf = valbuf;
  DEPRECATED_EXTRACT_RETURN_VALUE (type, registers, buf);
}

/* Implementation of store return value that grubs the register cache.
   Takes a local copy of the buffer to avoid const problems.  */
void
legacy_store_return_value (struct type *type, struct regcache *regcache,
			   const void *buf)
{
  bfd_byte *b = alloca (TYPE_LENGTH (type));
  gdb_assert (regcache == current_regcache);
  memcpy (b, buf, TYPE_LENGTH (type));
  DEPRECATED_STORE_RETURN_VALUE (type, b);
}


int
legacy_register_sim_regno (int regnum)
{
  /* Only makes sense to supply raw registers.  */
  gdb_assert (regnum >= 0 && regnum < NUM_REGS);
  /* NOTE: cagney/2002-05-13: The old code did it this way and it is
     suspected that some GDB/SIM combinations may rely on this
     behavour.  The default should be one2one_register_sim_regno
     (below).  */
  if (REGISTER_NAME (regnum) != NULL
      && REGISTER_NAME (regnum)[0] != '\0')
    return regnum;
  else
    return LEGACY_SIM_REGNO_IGNORE;
}

int
generic_frameless_function_invocation_not (struct frame_info *fi)
{
  return 0;
}

int
generic_return_value_on_stack_not (struct type *type)
{
  return 0;
}

CORE_ADDR
generic_skip_trampoline_code (CORE_ADDR pc)
{
  return 0;
}

int
generic_in_solib_call_trampoline (CORE_ADDR pc, char *name)
{
  return 0;
}

int
generic_in_solib_return_trampoline (CORE_ADDR pc, char *name)
{
  return 0;
}

int
generic_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  return 0;
}

const char *
legacy_register_name (int i)
{
#ifdef REGISTER_NAMES
  static char *names[] = REGISTER_NAMES;
  if (i < 0 || i >= (sizeof (names) / sizeof (*names)))
    return NULL;
  else
    return names[i];
#else
  internal_error (__FILE__, __LINE__,
		  "legacy_register_name: called.");
  return NULL;
#endif
}

#if defined (CALL_DUMMY)
LONGEST legacy_call_dummy_words[] = CALL_DUMMY;
#else
LONGEST legacy_call_dummy_words[1];
#endif
int legacy_sizeof_call_dummy_words = sizeof (legacy_call_dummy_words);

void
generic_remote_translate_xfer_address (CORE_ADDR gdb_addr, int gdb_len,
				       CORE_ADDR * rem_addr, int *rem_len)
{
  *rem_addr = gdb_addr;
  *rem_len = gdb_len;
}

int
generic_prologue_frameless_p (CORE_ADDR ip)
{
  return ip == SKIP_PROLOGUE (ip);
}

/* New/multi-arched targets should use the correct gdbarch field
   instead of using this global pointer. */
int
legacy_print_insn (bfd_vma vma, disassemble_info *info)
{
  return (*tm_print_insn) (vma, info);
}

/* Helper functions for INNER_THAN */

int
core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
{
  return (lhs < rhs);
}

int
core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
{
  return (lhs > rhs);
}


/* Helper functions for TARGET_{FLOAT,DOUBLE}_FORMAT */

const struct floatformat *
default_float_format (struct gdbarch *gdbarch)
{
#if GDB_MULTI_ARCH
  int byte_order = gdbarch_byte_order (gdbarch);
#else
  int byte_order = TARGET_BYTE_ORDER;
#endif
  switch (byte_order)
    {
    case BFD_ENDIAN_BIG:
      return &floatformat_ieee_single_big;
    case BFD_ENDIAN_LITTLE:
      return &floatformat_ieee_single_little;
    default:
      internal_error (__FILE__, __LINE__,
		      "default_float_format: bad byte order");
    }
}


const struct floatformat *
default_double_format (struct gdbarch *gdbarch)
{
#if GDB_MULTI_ARCH
  int byte_order = gdbarch_byte_order (gdbarch);
#else
  int byte_order = TARGET_BYTE_ORDER;
#endif
  switch (byte_order)
    {
    case BFD_ENDIAN_BIG:
      return &floatformat_ieee_double_big;
    case BFD_ENDIAN_LITTLE:
      return &floatformat_ieee_double_little;
    default:
      internal_error (__FILE__, __LINE__,
		      "default_double_format: bad byte order");
    }
}

/* Misc helper functions for targets. */

int
frame_num_args_unknown (struct frame_info *fi)
{
  return -1;
}


int
generic_register_convertible_not (int num)
{
  return 0;
}
  

/* Under some ABI's that specify the `struct convention' for returning
   structures by value, by the time we've returned from the function,
   the return value is sitting there in the caller's buffer, but GDB
   has no way to find the address of that buffer.

   On such architectures, use this function as your
   extract_struct_value_address method.  When asked to a struct
   returned by value in this fashion, GDB will print a nice error
   message, instead of garbage.  */
CORE_ADDR
generic_cannot_extract_struct_value_address (char *dummy)
{
  return 0;
}

CORE_ADDR
core_addr_identity (CORE_ADDR addr)
{
  return addr;
}

int
no_op_reg_to_regnum (int reg)
{
  return reg;
}

/* For use by frame_args_address and frame_locals_address.  */
CORE_ADDR
default_frame_address (struct frame_info *fi)
{
  return fi->frame;
}

/* Default prepare_to_procced().  */
int
default_prepare_to_proceed (int select_it)
{
  return 0;
}

/* Generic prepare_to_proceed().  This one should be suitable for most
   targets that support threads. */
int
generic_prepare_to_proceed (int select_it)
{
  ptid_t wait_ptid;
  struct target_waitstatus wait_status;

  /* Get the last target status returned by target_wait().  */
  get_last_target_status (&wait_ptid, &wait_status);

  /* Make sure we were stopped either at a breakpoint, or because
     of a Ctrl-C.  */
  if (wait_status.kind != TARGET_WAITKIND_STOPPED
      || (wait_status.value.sig != TARGET_SIGNAL_TRAP &&
          wait_status.value.sig != TARGET_SIGNAL_INT))
    {
      return 0;
    }

  if (!ptid_equal (wait_ptid, minus_one_ptid)
      && !ptid_equal (inferior_ptid, wait_ptid))
    {
      /* Switched over from WAIT_PID.  */
      CORE_ADDR wait_pc = read_pc_pid (wait_ptid);

      if (wait_pc != read_pc ())
	{
	  if (select_it)
	    {
	      /* Switch back to WAIT_PID thread.  */
	      inferior_ptid = wait_ptid;

	      /* FIXME: This stuff came from switch_to_thread() in
		 thread.c (which should probably be a public function).  */
	      flush_cached_frames ();
	      registers_changed ();
	      stop_pc = wait_pc;
	      select_frame (get_current_frame ());
	    }
          /* We return 1 to indicate that there is a breakpoint here,
             so we need to step over it before continuing to avoid
             hitting it straight away. */
          if (breakpoint_here_p (wait_pc))
            {
	      return 1;
            }
	}
    }
  return 0;
  
}

void
init_frame_pc_noop (int fromleaf, struct frame_info *prev)
{
  return;
}

void
init_frame_pc_default (int fromleaf, struct frame_info *prev)
{
  if (fromleaf)
    prev->pc = SAVED_PC_AFTER_CALL (prev->next);
  else if (prev->next != NULL)
    prev->pc = FRAME_SAVED_PC (prev->next);
  else
    prev->pc = read_pc ();
}

void
default_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
{
  return;
}

void
default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
{
  return;
}

int
cannot_register_not (int regnum)
{
  return 0;
}

/* Legacy version of target_virtual_frame_pointer().  Assumes that
   there is an FP_REGNUM and that it is the same, cooked or raw.  */

void
legacy_virtual_frame_pointer (CORE_ADDR pc,
			      int *frame_regnum,
			      LONGEST *frame_offset)
{
  gdb_assert (FP_REGNUM >= 0);
  *frame_regnum = FP_REGNUM;
  *frame_offset = 0;
}

/* Assume the world is sane, every register's virtual and real size
   is identical.  */

int
generic_register_size (int regnum)
{
  gdb_assert (regnum >= 0 && regnum < NUM_REGS + NUM_PSEUDO_REGS);
  return TYPE_LENGTH (REGISTER_VIRTUAL_TYPE (regnum));
}

#if !defined (IN_SIGTRAMP)
#if defined (SIGTRAMP_START)
#define IN_SIGTRAMP(pc, name) \
       ((pc) >= SIGTRAMP_START(pc)   \
        && (pc) < SIGTRAMP_END(pc) \
        )
#else
#define IN_SIGTRAMP(pc, name) \
       (name && STREQ ("_sigtramp", name))
#endif
#endif

/* Assume all registers are adjacent.  */

int
generic_register_byte (int regnum)
{
  int byte;
  int i;
  gdb_assert (regnum >= 0 && regnum < NUM_REGS + NUM_PSEUDO_REGS);
  byte = 0;
  for (i = 0; i < regnum; i++)
    {
      byte += TYPE_LENGTH (REGISTER_VIRTUAL_TYPE (i));
    }
  return byte;
}


int
legacy_pc_in_sigtramp (CORE_ADDR pc, char *name)
{
  return IN_SIGTRAMP(pc, name);
}

int
legacy_convert_register_p (int regnum)
{
  return REGISTER_CONVERTIBLE (regnum);
}

void
legacy_register_to_value (int regnum, struct type *type,
			  char *from, char *to)
{
  REGISTER_CONVERT_TO_VIRTUAL (regnum, type, from, to);
}

void
legacy_value_to_register (struct type *type, int regnum,
			  char *from, char *to)
{
  REGISTER_CONVERT_TO_RAW (type, regnum, from, to);
}


/* Functions to manipulate the endianness of the target.  */

/* ``target_byte_order'' is only used when non- multi-arch.
   Multi-arch targets obtain the current byte order using the
   TARGET_BYTE_ORDER gdbarch method.

   The choice of initial value is entirely arbitrary.  During startup,
   the function initialize_current_architecture() updates this value
   based on default byte-order information extracted from BFD.  */
int target_byte_order = BFD_ENDIAN_BIG;
int target_byte_order_auto = 1;

static const char endian_big[] = "big";
static const char endian_little[] = "little";
static const char endian_auto[] = "auto";
static const char *endian_enum[] =
{
  endian_big,
  endian_little,
  endian_auto,
  NULL,
};
static const char *set_endian_string;

/* Called by ``show endian''.  */

static void
show_endian (char *args, int from_tty)
{
  if (TARGET_BYTE_ORDER_AUTO)
    printf_unfiltered ("The target endianness is set automatically (currently %s endian)\n",
		       (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little"));
  else
    printf_unfiltered ("The target is assumed to be %s endian\n",
		       (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little"));
}

static void
set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
{
  if (set_endian_string == endian_auto)
    {
      target_byte_order_auto = 1;
    }
  else if (set_endian_string == endian_little)
    {
      target_byte_order_auto = 0;
      if (GDB_MULTI_ARCH)
	{
	  struct gdbarch_info info;
	  gdbarch_info_init (&info);
	  info.byte_order = BFD_ENDIAN_LITTLE;
	  if (! gdbarch_update_p (info))
	    {
	      printf_unfiltered ("Little endian target not supported by GDB\n");
	    }
	}
      else
	{
	  target_byte_order = BFD_ENDIAN_LITTLE;
	}
    }
  else if (set_endian_string == endian_big)
    {
      target_byte_order_auto = 0;
      if (GDB_MULTI_ARCH)
	{
	  struct gdbarch_info info;
	  gdbarch_info_init (&info);
	  info.byte_order = BFD_ENDIAN_BIG;
	  if (! gdbarch_update_p (info))
	    {
	      printf_unfiltered ("Big endian target not supported by GDB\n");
	    }
	}
      else
	{
	  target_byte_order = BFD_ENDIAN_BIG;
	}
    }
  else
    internal_error (__FILE__, __LINE__,
		    "set_endian: bad value");
  show_endian (NULL, from_tty);
}

/* Set the endianness from a BFD.  */

static void
set_endian_from_file (bfd *abfd)
{
  int want;
  if (GDB_MULTI_ARCH)
    internal_error (__FILE__, __LINE__,
		    "set_endian_from_file: not for multi-arch");
  if (bfd_big_endian (abfd))
    want = BFD_ENDIAN_BIG;
  else
    want = BFD_ENDIAN_LITTLE;
  if (TARGET_BYTE_ORDER_AUTO)
    target_byte_order = want;
  else if (TARGET_BYTE_ORDER != want)
    warning ("%s endian file does not match %s endian target.",
	     want == BFD_ENDIAN_BIG ? "big" : "little",
	     TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little");
}


/* Functions to manipulate the architecture of the target */

enum set_arch { set_arch_auto, set_arch_manual };

int target_architecture_auto = 1;

const char *set_architecture_string;

/* Old way of changing the current architecture. */

extern const struct bfd_arch_info bfd_default_arch_struct;
const struct bfd_arch_info *target_architecture = &bfd_default_arch_struct;
int (*target_architecture_hook) (const struct bfd_arch_info *ap);

static int
arch_ok (const struct bfd_arch_info *arch)
{
  if (GDB_MULTI_ARCH)
    internal_error (__FILE__, __LINE__,
		    "arch_ok: not multi-arched");
  /* Should be performing the more basic check that the binary is
     compatible with GDB. */
  /* Check with the target that the architecture is valid. */
  return (target_architecture_hook == NULL
	  || target_architecture_hook (arch));
}

static void
set_arch (const struct bfd_arch_info *arch,
          enum set_arch type)
{
  if (GDB_MULTI_ARCH)
    internal_error (__FILE__, __LINE__,
		    "set_arch: not multi-arched");
  switch (type)
    {
    case set_arch_auto:
      if (!arch_ok (arch))
	warning ("Target may not support %s architecture",
		 arch->printable_name);
      target_architecture = arch;
      break;
    case set_arch_manual:
      if (!arch_ok (arch))
	{
	  printf_unfiltered ("Target does not support `%s' architecture.\n",
			     arch->printable_name);
	}
      else
	{
	  target_architecture_auto = 0;
	  target_architecture = arch;
	}
      break;
    }
  if (gdbarch_debug)
    gdbarch_dump (current_gdbarch, gdb_stdlog);
}

/* Set the architecture from arch/machine (deprecated) */

void
set_architecture_from_arch_mach (enum bfd_architecture arch,
				 unsigned long mach)
{
  const struct bfd_arch_info *wanted = bfd_lookup_arch (arch, mach);
  if (GDB_MULTI_ARCH)
    internal_error (__FILE__, __LINE__,
		    "set_architecture_from_arch_mach: not multi-arched");
  if (wanted != NULL)
    set_arch (wanted, set_arch_manual);
  else
    internal_error (__FILE__, __LINE__,
		    "gdbarch: hardwired architecture/machine not recognized");
}

/* Set the architecture from a BFD (deprecated) */

static void
set_architecture_from_file (bfd *abfd)
{
  const struct bfd_arch_info *wanted = bfd_get_arch_info (abfd);
  if (GDB_MULTI_ARCH)
    internal_error (__FILE__, __LINE__,
		    "set_architecture_from_file: not multi-arched");
  if (target_architecture_auto)
    {
      set_arch (wanted, set_arch_auto);
    }
  else if (wanted != target_architecture)
    {
      warning ("%s architecture file may be incompatible with %s target.",
	       wanted->printable_name,
	       target_architecture->printable_name);
    }
}


/* Called if the user enters ``show architecture'' without an
   argument. */

static void
show_architecture (char *args, int from_tty)
{
  const char *arch;
  arch = TARGET_ARCHITECTURE->printable_name;
  if (target_architecture_auto)
    printf_filtered ("The target architecture is set automatically (currently %s)\n", arch);
  else
    printf_filtered ("The target architecture is assumed to be %s\n", arch);
}


/* Called if the user enters ``set architecture'' with or without an
   argument. */

static void
set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
{
  if (strcmp (set_architecture_string, "auto") == 0)
    {
      target_architecture_auto = 1;
    }
  else if (GDB_MULTI_ARCH)
    {
      struct gdbarch_info info;
      gdbarch_info_init (&info);
      info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
      if (info.bfd_arch_info == NULL)
	internal_error (__FILE__, __LINE__,
			"set_architecture: bfd_scan_arch failed");
      if (gdbarch_update_p (info))
	target_architecture_auto = 0;
      else
	printf_unfiltered ("Architecture `%s' not recognized.\n",
			   set_architecture_string);
    }
  else
    {
      const struct bfd_arch_info *arch
	= bfd_scan_arch (set_architecture_string);
      if (arch == NULL)
	internal_error (__FILE__, __LINE__,
			"set_architecture: bfd_scan_arch failed");
      set_arch (arch, set_arch_manual);
    }
  show_architecture (NULL, from_tty);
}

/* Set the dynamic target-system-dependent parameters (architecture,
   byte-order) using information found in the BFD */

void
set_gdbarch_from_file (bfd *abfd)
{
  if (GDB_MULTI_ARCH)
    {
      struct gdbarch_info info;
      gdbarch_info_init (&info);
      info.abfd = abfd;
      if (! gdbarch_update_p (info))
	error ("Architecture of file not recognized.\n");
    }
  else
    {
      set_architecture_from_file (abfd);
      set_endian_from_file (abfd);
    }
}

/* Initialize the current architecture.  Update the ``set
   architecture'' command so that it specifies a list of valid
   architectures.  */

#ifdef DEFAULT_BFD_ARCH
extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
#else
static const bfd_arch_info_type *default_bfd_arch;
#endif

#ifdef DEFAULT_BFD_VEC
extern const bfd_target DEFAULT_BFD_VEC;
static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
#else
static const bfd_target *default_bfd_vec;
#endif

void
initialize_current_architecture (void)
{
  const char **arches = gdbarch_printable_names ();

  /* determine a default architecture and byte order. */
  struct gdbarch_info info;
  gdbarch_info_init (&info);
  
  /* Find a default architecture. */
  if (info.bfd_arch_info == NULL
      && default_bfd_arch != NULL)
    info.bfd_arch_info = default_bfd_arch;
  if (info.bfd_arch_info == NULL)
    {
      /* Choose the architecture by taking the first one
	 alphabetically. */
      const char *chosen = arches[0];
      const char **arch;
      for (arch = arches; *arch != NULL; arch++)
	{
	  if (strcmp (*arch, chosen) < 0)
	    chosen = *arch;
	}
      if (chosen == NULL)
	internal_error (__FILE__, __LINE__,
			"initialize_current_architecture: No arch");
      info.bfd_arch_info = bfd_scan_arch (chosen);
      if (info.bfd_arch_info == NULL)
	internal_error (__FILE__, __LINE__,
			"initialize_current_architecture: Arch not found");
    }

  /* Take several guesses at a byte order.  */
  if (info.byte_order == BFD_ENDIAN_UNKNOWN
      && default_bfd_vec != NULL)
    {
      /* Extract BFD's default vector's byte order. */
      switch (default_bfd_vec->byteorder)
	{
	case BFD_ENDIAN_BIG:
	  info.byte_order = BFD_ENDIAN_BIG;
	  break;
	case BFD_ENDIAN_LITTLE:
	  info.byte_order = BFD_ENDIAN_LITTLE;
	  break;
	default:
	  break;
	}
    }
  if (info.byte_order == BFD_ENDIAN_UNKNOWN)
    {
      /* look for ``*el-*'' in the target name. */
      const char *chp;
      chp = strchr (target_name, '-');
      if (chp != NULL
	  && chp - 2 >= target_name
	  && strncmp (chp - 2, "el", 2) == 0)
	info.byte_order = BFD_ENDIAN_LITTLE;
    }
  if (info.byte_order == BFD_ENDIAN_UNKNOWN)
    {
      /* Wire it to big-endian!!! */
      info.byte_order = BFD_ENDIAN_BIG;
    }

  if (GDB_MULTI_ARCH)
    {
      if (! gdbarch_update_p (info))
	{
	  internal_error (__FILE__, __LINE__,
			  "initialize_current_architecture: Selection of initial architecture failed");
	}
    }
  else
    {
      /* If the multi-arch logic comes up with a byte-order (from BFD)
         use it for the non-multi-arch case.  */
      if (info.byte_order != BFD_ENDIAN_UNKNOWN)
	target_byte_order = info.byte_order;
      initialize_non_multiarch ();
    }

  /* Create the ``set architecture'' command appending ``auto'' to the
     list of architectures. */
  {
    struct cmd_list_element *c;
    /* Append ``auto''. */
    int nr;
    for (nr = 0; arches[nr] != NULL; nr++);
    arches = xrealloc (arches, sizeof (char*) * (nr + 2));
    arches[nr + 0] = "auto";
    arches[nr + 1] = NULL;
    /* FIXME: add_set_enum_cmd() uses an array of ``char *'' instead
       of ``const char *''.  We just happen to know that the casts are
       safe. */
    c = add_set_enum_cmd ("architecture", class_support,
			  arches, &set_architecture_string,
			  "Set architecture of target.",
			  &setlist);
    set_cmd_sfunc (c, set_architecture);
    add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
    /* Don't use set_from_show - need to print both auto/manual and
       current setting. */
    add_cmd ("architecture", class_support, show_architecture,
	     "Show the current target architecture", &showlist);
  }
}


/* Initialize a gdbarch info to values that will be automatically
   overridden.  Note: Originally, this ``struct info'' was initialized
   using memset(0).  Unfortunatly, that ran into problems, namely
   BFD_ENDIAN_BIG is zero.  An explicit initialization function that
   can explicitly set each field to a well defined value is used.  */

void
gdbarch_info_init (struct gdbarch_info *info)
{
  memset (info, 0, sizeof (struct gdbarch_info));
  info->byte_order = BFD_ENDIAN_UNKNOWN;
}

/* */

extern initialize_file_ftype _initialize_gdbarch_utils;

void
_initialize_gdbarch_utils (void)
{
  struct cmd_list_element *c;
  c = add_set_enum_cmd ("endian", class_support,
			endian_enum, &set_endian_string,
			"Set endianness of target.",
			&setlist);
  set_cmd_sfunc (c, set_endian);
  /* Don't use set_from_show - need to print both auto/manual and
     current setting. */
  add_cmd ("endian", class_support, show_endian,
	   "Show the current byte-order", &showlist);
}