summaryrefslogtreecommitdiff
path: root/gcc/common/config/arm/arm-common.c
blob: 38bd3a725b1442eaff1742cb3464806b1d58fa1b (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
/* Common hooks for ARM.
   Copyright (C) 1991-2017 Free Software Foundation, Inc.

   This file is part of GCC.

   GCC 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 3, or (at your
   option) any later version.

   GCC 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 GCC; see the file COPYING3.  If not see
   <http://www.gnu.org/licenses/>.  */

#define INCLUDE_LIST
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "memmodel.h"
#include "tm_p.h"
#include "common/common-target.h"
#include "common/common-target-def.h"
#include "opts.h"
#include "flags.h"
#include "sbitmap.h"
#include "diagnostic.h"

/* Set default optimization options.  */
static const struct default_options arm_option_optimization_table[] =
  {
    /* Enable section anchors by default at -O1 or higher.  */
    { OPT_LEVELS_1_PLUS, OPT_fsection_anchors, NULL, 1 },
    { OPT_LEVELS_1_PLUS, OPT_fomit_frame_pointer, NULL, 1 },
    { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
    { OPT_LEVELS_NONE, 0, NULL, 0 }
  };

/* Implement TARGET_EXCEPT_UNWIND_INFO.  */

enum unwind_info_type
arm_except_unwind_info (struct gcc_options *opts)
{
  /* Honor the --enable-sjlj-exceptions configure switch.  */
#ifdef CONFIG_SJLJ_EXCEPTIONS
  if (CONFIG_SJLJ_EXCEPTIONS)
    return UI_SJLJ;
#endif

  /* If not using ARM EABI unwind tables... */
  if (ARM_UNWIND_INFO)
    {
      /* For simplicity elsewhere in this file, indicate that all unwind
	 info is disabled if we're not emitting unwind tables.  */
      if (!opts->x_flag_exceptions && !opts->x_flag_unwind_tables)
	return UI_NONE;
      else
	return UI_TARGET;
    }

  /* ... we use sjlj exceptions for backwards compatibility.  */
  return UI_SJLJ;
}

#define ARM_CPU_NAME_LENGTH 20

/* Truncate NAME at the first '.' or '+' character seen, or return
   NAME unmodified.  */

const char *
arm_rewrite_selected_cpu (const char *name)
{
  static char output_buf[ARM_CPU_NAME_LENGTH + 1] = {0};
  char *arg_pos;

  strncpy (output_buf, name, ARM_CPU_NAME_LENGTH);
  output_buf[ARM_CPU_NAME_LENGTH] = 0;

  arg_pos = strchr (output_buf, '.');

  /* If we found a '.' truncate the entry at that point.  */
  if (arg_pos)
    *arg_pos = '\0';

  arg_pos = strchr (output_buf, '+');

  /* If we found a '+' truncate the entry at that point.  */
  if (arg_pos)
    *arg_pos = '\0';

  return output_buf;
}

/* Called by the driver to rewrite a name passed to the -mcpu
   argument in preparation to be passed to the assembler.  The
   names passed from the command line will be in ARGV, we want
   to use the right-most argument, which should be in
   ARGV[ARGC - 1].  ARGC should always be greater than 0.  */

const char *
arm_rewrite_mcpu (int argc, const char **argv)
{
  gcc_assert (argc);
  return arm_rewrite_selected_cpu (argv[argc - 1]);
}

/* Truncate NAME at the first '+' character seen, or return
   NAME unmodified.  Similar to arm_rewrite_selected_cpu, but we must
   preserve '.' as that is part of some architecture names.  */

const char *
arm_rewrite_selected_arch (const char *name)
{
  static char output_buf[ARM_CPU_NAME_LENGTH + 1] = {0};
  char *arg_pos;

  strncpy (output_buf, name, ARM_CPU_NAME_LENGTH);
  output_buf[ARM_CPU_NAME_LENGTH] = 0;

  arg_pos = strchr (output_buf, '+');

  /* If we found a '+' truncate the entry at that point.  */
  if (arg_pos)
    *arg_pos = '\0';

  return output_buf;
}

/* Called by the driver to rewrite a name passed to the -march
   argument in preparation to be passed to the assembler.  The
   names passed from the command line will be in ARGV, we want
   to use the right-most argument, which should be in
   ARGV[ARGC - 1].  ARGC should always be greater than 0.  */

const char *
arm_rewrite_march (int argc, const char **argv)
{
  gcc_assert (argc);
  return arm_rewrite_selected_arch (argv[argc - 1]);
}

#include "arm-cpu-cdata.h"

/* Scan over a raw feature array BITS checking for BIT being present.
   This is slower than the normal bitmask checks, but we would spend longer
   initializing that than doing the check this way.  Returns true iff
   BIT is found.  */
static bool
check_isa_bits_for (const enum isa_feature* bits, enum isa_feature bit)
{
  while (*bits != isa_nobit)
    if (*bits++ == bit)
      return true;

  return false;
}

/* Called by the driver to check whether the target denoted by current
   command line options is a Thumb-only target.  ARGV is an array of
   tupples (normally only one) where the first element of the tupple
   is 'cpu' or 'arch' and the second is the option passed to the
   compiler for that.  An architecture tupple is always taken in
   preference to a cpu tupple and the last of each type always
   overrides any earlier setting.  */

const char *
arm_target_thumb_only (int argc, const char **argv)
{
  const char *arch = NULL;
  const char *cpu = NULL;

  if (argc % 2 != 0)
    fatal_error (input_location,
		 "%%:target_mode_check takes an even number of parameters");

  while (argc)
    {
      if (strcmp (argv[0], "arch") == 0)
	arch = argv[1];
      else if (strcmp (argv[0], "cpu") == 0)
	cpu = argv[1];
      else
	fatal_error (input_location,
		     "unrecognized option passed to %%:target_mode_check");
      argc -= 2;
      argv += 2;
    }

  /* No architecture, or CPU, has option extensions that change
     whether or not we have a Thumb-only device, so there is no need
     to scan any option extensions specified.  */

  /* If the architecture is specified, that overrides any CPU setting.  */
  if (arch)
    {
      const arch_option *arch_opt
	= arm_parse_arch_option_name (all_architectures, "-march", arch);

      if (arch_opt && !check_isa_bits_for (arch_opt->common.isa_bits,
					   isa_bit_notm))
	return "-mthumb";
    }
  else if (cpu)
    {
      const cpu_option *cpu_opt
	= arm_parse_cpu_option_name (all_cores, "-mcpu", cpu);

      if (cpu_opt && !check_isa_bits_for (cpu_opt->common.isa_bits,
					  isa_bit_notm))
	return "-mthumb";
    }

  /* Compiler hasn't been configured with a default, and the CPU
     doesn't require Thumb, so default to ARM.  */
  return "-marm";
}

/* List the permitted CPU option names.  If TARGET is a near miss for an
   entry, print out the suggested alternative.  */
static void
arm_print_hint_for_cpu_option (const char *target,
			       const cpu_option *list)
{
  auto_vec<const char*> candidates;
  for (; list->common.name != NULL; list++)
    candidates.safe_push (list->common.name);
  char *s;
  const char *hint = candidates_list_and_hint (target, s, candidates);
  if (hint)
    inform (input_location, "valid arguments are: %s; did you mean %qs?",
	    s, hint);
  else
    inform (input_location, "valid arguments are: %s", s);

  XDELETEVEC (s);
}

/* Parse the base component of a CPU selection in LIST.  Return a
   pointer to the entry in the architecture table.  OPTNAME is the
   name of the option we are parsing and can be used if a diagnostic
   is needed.  */
const cpu_option *
arm_parse_cpu_option_name (const cpu_option *list, const char *optname,
			   const char *target)
{
  const cpu_option *entry;
  const char *end  = strchr (target, '+');
  size_t len = end ? end - target : strlen (target);

  for (entry = list; entry->common.name != NULL; entry++)
    {
      if (strncmp (entry->common.name, target, len) == 0
	  && entry->common.name[len] == '\0')
	return entry;
    }

  error_at (input_location, "unrecognized %s target: %s", optname, target);
  arm_print_hint_for_cpu_option (target, list);
  return NULL;
}

/* List the permitted architecture option names.  If TARGET is a near
   miss for an entry, print out the suggested alternative.  */
static void
arm_print_hint_for_arch_option (const char *target,
			       const arch_option *list)
{
  auto_vec<const char*> candidates;
  for (; list->common.name != NULL; list++)
    candidates.safe_push (list->common.name);
  char *s;
  const char *hint = candidates_list_and_hint (target, s, candidates);
  if (hint)
    inform (input_location, "valid arguments are: %s; did you mean %qs?",
	    s, hint);
  else
    inform (input_location, "valid arguments are: %s", s);

  XDELETEVEC (s);
}

/* Parse the base component of a CPU or architecture selection in
   LIST.  Return a pointer to the entry in the architecture table.
   OPTNAME is the name of the option we are parsing and can be used if
   a diagnostic is needed.  */
const arch_option *
arm_parse_arch_option_name (const arch_option *list, const char *optname,
			    const char *target)
{
  const arch_option *entry;
  const char *end  = strchr (target, '+');
  size_t len = end ? end - target : strlen (target);

  for (entry = list; entry->common.name != NULL; entry++)
    {
      if (strncmp (entry->common.name, target, len) == 0
	  && entry->common.name[len] == '\0')
	return entry;
    }

  error_at (input_location, "unrecognized %s target: %s", optname, target);
  arm_print_hint_for_arch_option (target, list);
  return NULL;
}

/* List the permitted architecture option names.  If TARGET is a near
   miss for an entry, print out the suggested alternative.  */
static void
arm_print_hint_for_fpu_option (const char *target)
{
  auto_vec<const char*> candidates;
  for (int i = 0; i < TARGET_FPU_auto; i++)
    candidates.safe_push (all_fpus[i].name);
  char *s;
  const char *hint = candidates_list_and_hint (target, s, candidates);
  if (hint)
    inform (input_location, "valid arguments are: %s; did you mean %qs?",
	    s, hint);
  else
    inform (input_location, "valid arguments are: %s", s);

  XDELETEVEC (s);
}

static const arm_fpu_desc *
arm_parse_fpu_option (const char *opt)
{
  int i;

  for (i = 0; i < TARGET_FPU_auto; i++)
    {
      if (strcmp (all_fpus[i].name, opt) == 0)
	return all_fpus + i;
    }

  error_at (input_location, "unrecognized -mfpu target: %s", opt);
  arm_print_hint_for_fpu_option (opt);
  return NULL;
}

/* Convert a static initializer array of feature bits to sbitmap
   representation.  */
void
arm_initialize_isa (sbitmap isa, const enum isa_feature *isa_bits)
{
  bitmap_clear (isa);
  while (*isa_bits != isa_nobit)
    bitmap_set_bit (isa, *(isa_bits++));
}

/* OPT isn't a recognized feature.  Print a suitable error message and
   suggest a possible value.  Always print the list of permitted
   values.  */
static void
arm_unrecognized_feature (const char *opt, size_t len,
			  const cpu_arch_option *target)
{
  char *this_opt = XALLOCAVEC (char, len+1);
  auto_vec<const char*> candidates;

  strncpy (this_opt, opt, len);
  this_opt[len] = 0;

  error_at (input_location, "%qs does not support feature %qs", target->name,
	    this_opt);
  for (const cpu_arch_extension *list = target->extensions;
       list->name != NULL;
       list++)
    candidates.safe_push (list->name);

  char *s;
  const char *hint = candidates_list_and_hint (this_opt, s, candidates);

  if (hint)
    inform (input_location, "valid feature names are: %s; did you mean %qs?",
	    s, hint);
  else
    inform (input_location, "valid feature names are: %s", s);

  XDELETEVEC (s);
}

/* Parse any feature extensions to add to (or remove from) the
   permitted ISA selection.  */
void
arm_parse_option_features (sbitmap isa, const cpu_arch_option *target,
			   const char *opts_in)
{
  const char *opts = opts_in;

  if (!opts)
    return;

  if (!target->extensions)
    {
      error_at (input_location, "%s does not take any feature options",
		target->name);
      return;
    }

  while (opts)
    {
      gcc_assert (*opts == '+');
      const struct cpu_arch_extension *entry;
      const char *end = strchr (++opts, '+');
      size_t len = end ? end - opts : strlen (opts);
      bool matched = false;

      for (entry = target->extensions;
	   !matched && entry->name != NULL;
	   entry++)
	{
	  if (strncmp (entry->name, opts, len) == 0
	      && entry->name[len] == '\0')
	    {
	      if (isa)
		{
		  const enum isa_feature *f = entry->isa_bits;
		  if (entry->remove)
		    {
		      while (*f != isa_nobit)
			bitmap_clear_bit (isa, *(f++));
		    }
		  else
		    {
		      while (*f != isa_nobit)
			bitmap_set_bit (isa, *(f++));
		    }
		}
	      matched = true;
	    }
	}

      if (!matched)
	arm_unrecognized_feature (opts, len, target);

      opts = end;
    }
}

class candidate_extension
{
public:
  const cpu_arch_extension *extension;
  sbitmap isa_bits;
  bool required;

  candidate_extension (const cpu_arch_extension *ext, sbitmap bits)
    : extension (ext), isa_bits (bits), required (true)
    {}
  ~candidate_extension ()
    {
      sbitmap_free (isa_bits);
    }
};

/* Generate a canonical representation of the -march option from the
   current -march string (if given) and other options on the command
   line that might affect the architecture.  This aids multilib selection
   by ensuring that:
   a) the option is always present
   b) only the minimal set of options are used
   c) when there are multiple extensions, they are in a consistent order.

   The options array consists of couplets of information where the
   first item in each couplet is the string describing which option
   name was selected (arch, cpu, fpu) and the second is the value
   passed for that option.  */
const char *
arm_canon_arch_option (int argc, const char **argv)
{
  const char *arch = NULL;
  const char *cpu = NULL;
  const char *fpu = NULL;
  const char *abi = NULL;
  static char *canonical_arch = NULL;

  /* Just in case we're called more than once.  */
  if (canonical_arch)
    {
      free (canonical_arch);
      canonical_arch = NULL;
    }

  if (argc & 1)
    fatal_error (input_location,
		 "%%:canon_for_mlib takes 1 or more pairs of parameters");

  while (argc)
    {
      if (strcmp (argv[0], "arch") == 0)
	arch = argv[1];
      else if (strcmp (argv[0], "cpu") == 0)
	cpu = argv[1];
      else if (strcmp (argv[0], "fpu") == 0)
	fpu = argv[1];
      else if (strcmp (argv[0], "abi") == 0)
	abi = argv[1];
      else
	fatal_error (input_location,
		     "unrecognized operand to %%:canon_for_mlib");

      argc -= 2;
      argv += 2;
    }

  auto_sbitmap target_isa (isa_num_bits);
  auto_sbitmap base_isa (isa_num_bits);
  auto_sbitmap fpu_isa (isa_num_bits);

  bitmap_clear (fpu_isa);

  const arch_option *selected_arch = NULL;

  /* At least one of these must be defined by either the specs or the
     user.  */
  gcc_assert (cpu || arch);

  if (!fpu)
    fpu = FPUTYPE_AUTO;

  if (!abi)
    {
      if (TARGET_DEFAULT_FLOAT_ABI == ARM_FLOAT_ABI_SOFT)
	abi = "soft";
      else if (TARGET_DEFAULT_FLOAT_ABI == ARM_FLOAT_ABI_SOFTFP)
	abi = "softfp";
      else if (TARGET_DEFAULT_FLOAT_ABI == ARM_FLOAT_ABI_HARD)
	abi = "hard";
    }

  /* First build up a bitmap describing the target architecture.  */
  if (arch)
    {
      selected_arch = arm_parse_arch_option_name (all_architectures,
						  "-march", arch);

      if (selected_arch == NULL)
	return "";

      arm_initialize_isa (target_isa, selected_arch->common.isa_bits);
      arm_parse_option_features (target_isa, &selected_arch->common,
				 strchr (arch, '+'));
      if (fpu && strcmp (fpu, "auto") != 0)
	{
	  /* We assume that architectures do not have any FPU bits
	     enabled by default.  If they did, we would need to strip
	     these out first.  */
	  const arm_fpu_desc *target_fpu = arm_parse_fpu_option (fpu);
	  if (target_fpu == NULL)
	    return "";

	  arm_initialize_isa (fpu_isa, target_fpu->isa_bits);
	  bitmap_ior (target_isa, target_isa, fpu_isa);
	}
    }
  else if (cpu)
    {
      const cpu_option *selected_cpu
	= arm_parse_cpu_option_name (all_cores, "-mcpu", cpu);

      if (selected_cpu == NULL)
	return "";

      arm_initialize_isa (target_isa, selected_cpu->common.isa_bits);
      arm_parse_option_features (target_isa, &selected_cpu->common,
				 strchr (cpu, '+'));
      if (fpu && strcmp (fpu, "auto") != 0)
	{
	  /* The easiest and safest way to remove the default fpu
	     capabilities is to look for a '+no..' option that removes
	     the base FPU bit (isa_bit_VFPv2).  If that doesn't exist
	     then the best we can do is strip out all the bits that
	     might be part of the most capable FPU we know about,
	     which is "crypto-neon-fp-armv8".  */
	  bool default_fpu_found = false;
	  if (selected_cpu->common.extensions)
	    {
	      const cpu_arch_extension *ext;
	      for (ext = selected_cpu->common.extensions; ext->name != NULL;
		   ++ext)
		{
		  if (ext->remove
		      && check_isa_bits_for (ext->isa_bits, isa_bit_VFPv2))
		    {
		      arm_initialize_isa (fpu_isa, ext->isa_bits);
		      bitmap_and_compl (target_isa, target_isa, fpu_isa);
		      default_fpu_found = true;
		    }
		}

	    }

	  if (!default_fpu_found)
	    {
	      arm_initialize_isa
		(fpu_isa,
		 all_fpus[TARGET_FPU_crypto_neon_fp_armv8].isa_bits);
	      bitmap_and_compl (target_isa, target_isa, fpu_isa);
	    }

	  const arm_fpu_desc *target_fpu = arm_parse_fpu_option (fpu);
	  if (target_fpu == NULL)
	    return "";

	  arm_initialize_isa (fpu_isa, target_fpu->isa_bits);
	  bitmap_ior (target_isa, target_isa, fpu_isa);
	}

      selected_arch = all_architectures + selected_cpu->arch;
    }

  /* If we have a soft-float ABI, disable the FPU.  */
  if (abi && strcmp (abi, "soft") == 0)
    {
      /* Clearing the VFPv2 bit is sufficient to stop any extention that
	 builds on the FPU from matching.  */
      bitmap_clear_bit (target_isa, isa_bit_VFPv2);
    }

  /* If we don't have a selected architecture by now, something's
     badly wrong.  */
  gcc_assert (selected_arch);

  arm_initialize_isa (base_isa, selected_arch->common.isa_bits);

  /* Architecture has no extension options, so just return the canonical
     architecture name.  */
  if (selected_arch->common.extensions == NULL)
    return selected_arch->common.name;

  /* We're only interested in extension bits.  */
  bitmap_and_compl (target_isa, target_isa, base_isa);

  /* There are no extensions needed.  Just return the canonical architecture
     name.  */
  if (bitmap_empty_p (target_isa))
    return selected_arch->common.name;

  /* What is left is the architecture that the compiler will target.  We
     now need to map that back into a suitable option+features list.

     The list is built in two passes.  First we scan every additive
     option feature supported by the architecture.  If the option
     provides a subset of the features we need we add it to the list
     of candidates.  We then scan backwards over the list of
     candidates and if we find a feature that adds nothing to one that
     was later in the list we mark it as redundant.  The result is a
     minimal list of required features for the target
     architecture.  */

  std::list<candidate_extension *> extensions;

  auto_sbitmap target_isa_unsatisfied (isa_num_bits);
  bitmap_copy (target_isa_unsatisfied, target_isa);

  sbitmap isa_bits = NULL;
  for (const cpu_arch_extension *cand = selected_arch->common.extensions;
       cand->name != NULL;
       cand++)
    {
      if (cand->remove || cand->alias)
	continue;

      if (isa_bits == NULL)
	isa_bits = sbitmap_alloc (isa_num_bits);

      arm_initialize_isa (isa_bits, cand->isa_bits);
      if (bitmap_subset_p (isa_bits, target_isa))
	{
	  extensions.push_back (new candidate_extension (cand, isa_bits));
	  bitmap_and_compl (target_isa_unsatisfied, target_isa_unsatisfied,
			    isa_bits);
	  isa_bits = NULL;
	}
    }

  /* There's one extra case to consider, which is that the user has
     specified an FPU that is less capable than this architecture
     supports.  In that case the code above will fail to find a
     suitable feature.  We handle this by scanning the list of options
     again, matching the first option that provides an FPU that is
     more capable than the selected FPU.

     Note that the other case (user specified a more capable FPU than
     this architecture supports) should end up selecting the most
     capable FPU variant that we do support.  This is sufficient for
     multilib selection.  */

  if (bitmap_bit_p (target_isa_unsatisfied, isa_bit_VFPv2)
      && bitmap_bit_p (fpu_isa, isa_bit_VFPv2))
    {
      std::list<candidate_extension *>::iterator ipoint = extensions.begin ();

      for (const cpu_arch_extension *cand = selected_arch->common.extensions;
	   cand->name != NULL;
	   cand++)
	{
	  if (cand->remove || cand->alias)
	    continue;

	  if (isa_bits == NULL)
	    isa_bits = sbitmap_alloc (isa_num_bits);

	  /* We need to keep the features in canonical order, so move the
	     insertion point if this feature is a candidate.  */
	  if (ipoint != extensions.end ()
	      && (*ipoint)->extension == cand)
	    ++ipoint;

	  arm_initialize_isa (isa_bits, cand->isa_bits);
	  if (bitmap_subset_p (fpu_isa, isa_bits))
	    {
	      extensions.insert (ipoint,
				 new candidate_extension (cand, isa_bits));
	      isa_bits = NULL;
	      break;
	    }
	}
    }

  if (isa_bits)
    sbitmap_free (isa_bits);

  bitmap_clear (target_isa);
  size_t len = 1;
  for (std::list<candidate_extension *>::reverse_iterator riter
	 = extensions.rbegin ();
       riter != extensions.rend (); ++riter)
    {
      if (bitmap_subset_p ((*riter)->isa_bits, target_isa))
	(*riter)->required = false;
      else
	{
	  bitmap_ior (target_isa, target_isa, (*riter)->isa_bits);
	  len += strlen ((*riter)->extension->name) + 1;
	}
    }

  canonical_arch
    = (char *) xmalloc (len + strlen (selected_arch->common.name));

  strcpy (canonical_arch, selected_arch->common.name);

  for (std::list<candidate_extension *>::iterator iter = extensions.begin ();
       iter != extensions.end (); ++iter)
    {
      if ((*iter)->required)
	{
	  strcat (canonical_arch, "+");
	  strcat (canonical_arch, (*iter)->extension->name);
	}
      delete (*iter);
    }

  return canonical_arch;
}

/* If building big-endian on a BE8 target generate a --be8 option for
   the linker.  Takes four types of option: "little" - little-endian;
   "big" - big-endian; "be8" - force be8 iff big-endian; and "arch"
   "<arch-name>" (two arguments) - the target architecture.  The
   parameter names are generated by the driver from the command-line
   options.  */
const char *
arm_be8_option (int argc, const char **argv)
{
  int endian = TARGET_ENDIAN_DEFAULT;
  const char *arch = NULL;
  int arg;
  bool force = false;

  for (arg = 0; arg < argc; arg++)
    {
      if (strcmp (argv[arg], "little") == 0)
	endian = 0;
      else if (strcmp (argv[arg], "big") == 0)
	endian = 1;
      else if (strcmp (argv[arg], "be8") == 0)
	force = true;
      else if (strcmp (argv[arg], "arch") == 0)
	{
	  arg++;
	  gcc_assert (arg < argc);
	  arch = argv[arg];
	}
      else
	gcc_unreachable ();
    }

  /* Little endian - no be8 option.  */
  if (!endian)
    return "";

  if (force)
    return "--be8";

  /* Arch might not be set iff arm_canon_arch (above) detected an
     error.  Do nothing in that case.  */
  if (!arch)
    return "";

  const arch_option *selected_arch
    = arm_parse_arch_option_name (all_architectures, "-march", arch);

  /* Similarly if the given arch option was itself invalid.  */
  if (!selected_arch)
    return "";

  if (check_isa_bits_for (selected_arch->common.isa_bits, isa_bit_be8))
    return "--be8";

  return "";
}

#undef ARM_CPU_NAME_LENGTH


#undef  TARGET_DEFAULT_TARGET_FLAGS
#define TARGET_DEFAULT_TARGET_FLAGS (TARGET_DEFAULT | MASK_SCHED_PROLOG)

#undef  TARGET_OPTION_OPTIMIZATION_TABLE
#define TARGET_OPTION_OPTIMIZATION_TABLE arm_option_optimization_table

#undef TARGET_EXCEPT_UNWIND_INFO
#define TARGET_EXCEPT_UNWIND_INFO  arm_except_unwind_info

struct gcc_targetm_common targetm_common = TARGETM_COMMON_INITIALIZER;