aboutsummaryrefslogtreecommitdiff
path: root/scripts/decodetree.py
blob: c1bf3cfa85f71fd2148ce4e1927df634652c76d5 (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
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
#!/usr/bin/env python3
# Copyright (c) 2018 Linaro Limited
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <http://www.gnu.org/licenses/>.
#

#
# Generate a decoding tree from a specification file.
# See the syntax and semantics in docs/devel/decodetree.rst.
#

import os
import re
import sys
import getopt

insnwidth = 32
insnmask = 0xffffffff
variablewidth = False
fields = {}
arguments = {}
formats = {}
allpatterns = []
anyextern = False

translate_prefix = 'trans'
translate_scope = 'static '
input_file = ''
output_file = None
output_fd = None
insntype = 'uint32_t'
decode_function = 'decode'

# An identifier for C.
re_C_ident = '[a-zA-Z][a-zA-Z0-9_]*'

# Identifiers for Arguments, Fields, Formats and Patterns.
re_arg_ident = '&[a-zA-Z0-9_]*'
re_fld_ident = '%[a-zA-Z0-9_]*'
re_fmt_ident = '@[a-zA-Z0-9_]*'
re_pat_ident = '[a-zA-Z0-9_]*'

def error_with_file(file, lineno, *args):
    """Print an error message from file:line and args and exit."""
    global output_file
    global output_fd

    prefix = ''
    if file:
        prefix += '{0}:'.format(file)
    if lineno:
        prefix += '{0}:'.format(lineno)
    if prefix:
        prefix += ' '
    print(prefix, end='error: ', file=sys.stderr)
    print(*args, file=sys.stderr)

    if output_file and output_fd:
        output_fd.close()
        os.remove(output_file)
    exit(1)
# end error_with_file


def error(lineno, *args):
    error_with_file(input_file, lineno, *args)
# end error


def output(*args):
    global output_fd
    for a in args:
        output_fd.write(a)


def output_autogen():
    output('/* This file is autogenerated by scripts/decodetree.py.  */\n\n')


def str_indent(c):
    """Return a string with C spaces"""
    return ' ' * c


def str_fields(fields):
    """Return a string uniquely identifying FIELDS"""
    r = ''
    for n in sorted(fields.keys()):
        r += '_' + n
    return r[1:]


def str_match_bits(bits, mask):
    """Return a string pretty-printing BITS/MASK"""
    global insnwidth

    i = 1 << (insnwidth - 1)
    space = 0x01010100
    r = ''
    while i != 0:
        if i & mask:
            if i & bits:
                r += '1'
            else:
                r += '0'
        else:
            r += '.'
        if i & space:
            r += ' '
        i >>= 1
    return r


def is_pow2(x):
    """Return true iff X is equal to a power of 2."""
    return (x & (x - 1)) == 0


def ctz(x):
    """Return the number of times 2 factors into X."""
    assert x != 0
    r = 0
    while ((x >> r) & 1) == 0:
        r += 1
    return r


def is_contiguous(bits):
    if bits == 0:
        return -1
    shift = ctz(bits)
    if is_pow2((bits >> shift) + 1):
        return shift
    else:
        return -1


def eq_fields_for_args(flds_a, flds_b):
    if len(flds_a) != len(flds_b):
        return False
    for k, a in flds_a.items():
        if k not in flds_b:
            return False
    return True


def eq_fields_for_fmts(flds_a, flds_b):
    if len(flds_a) != len(flds_b):
        return False
    for k, a in flds_a.items():
        if k not in flds_b:
            return False
        b = flds_b[k]
        if a.__class__ != b.__class__ or a != b:
            return False
    return True


class Field:
    """Class representing a simple instruction field"""
    def __init__(self, sign, pos, len):
        self.sign = sign
        self.pos = pos
        self.len = len
        self.mask = ((1 << len) - 1) << pos

    def __str__(self):
        if self.sign:
            s = 's'
        else:
            s = ''
        return str(self.pos) + ':' + s + str(self.len)

    def str_extract(self):
        if self.sign:
            extr = 'sextract32'
        else:
            extr = 'extract32'
        return '{0}(insn, {1}, {2})'.format(extr, self.pos, self.len)

    def __eq__(self, other):
        return self.sign == other.sign and self.mask == other.mask

    def __ne__(self, other):
        return not self.__eq__(other)
# end Field


class MultiField:
    """Class representing a compound instruction field"""
    def __init__(self, subs, mask):
        self.subs = subs
        self.sign = subs[0].sign
        self.mask = mask

    def __str__(self):
        return str(self.subs)

    def str_extract(self):
        ret = '0'
        pos = 0
        for f in reversed(self.subs):
            if pos == 0:
                ret = f.str_extract()
            else:
                ret = 'deposit32({0}, {1}, {2}, {3})' \
                      .format(ret, pos, 32 - pos, f.str_extract())
            pos += f.len
        return ret

    def __ne__(self, other):
        if len(self.subs) != len(other.subs):
            return True
        for a, b in zip(self.subs, other.subs):
            if a.__class__ != b.__class__ or a != b:
                return True
        return False

    def __eq__(self, other):
        return not self.__ne__(other)
# end MultiField


class ConstField:
    """Class representing an argument field with constant value"""
    def __init__(self, value):
        self.value = value
        self.mask = 0
        self.sign = value < 0

    def __str__(self):
        return str(self.value)

    def str_extract(self):
        return str(self.value)

    def __cmp__(self, other):
        return self.value - other.value
# end ConstField


class FunctionField:
    """Class representing a field passed through a function"""
    def __init__(self, func, base):
        self.mask = base.mask
        self.sign = base.sign
        self.base = base
        self.func = func

    def __str__(self):
        return self.func + '(' + str(self.base) + ')'

    def str_extract(self):
        return self.func + '(ctx, ' + self.base.str_extract() + ')'

    def __eq__(self, other):
        return self.func == other.func and self.base == other.base

    def __ne__(self, other):
        return not self.__eq__(other)
# end FunctionField


class ParameterField:
    """Class representing a pseudo-field read from a function"""
    def __init__(self, func):
        self.mask = 0
        self.sign = 0
        self.func = func

    def __str__(self):
        return self.func

    def str_extract(self):
        return self.func + '(ctx)'

    def __eq__(self, other):
        return self.func == other.func

    def __ne__(self, other):
        return not self.__eq__(other)
# end ParameterField


class Arguments:
    """Class representing the extracted fields of a format"""
    def __init__(self, nm, flds, extern):
        self.name = nm
        self.extern = extern
        self.fields = sorted(flds)

    def __str__(self):
        return self.name + ' ' + str(self.fields)

    def struct_name(self):
        return 'arg_' + self.name

    def output_def(self):
        if not self.extern:
            output('typedef struct {\n')
            for n in self.fields:
                output('    int ', n, ';\n')
            output('} ', self.struct_name(), ';\n\n')
# end Arguments


class General:
    """Common code between instruction formats and instruction patterns"""
    def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds, w):
        self.name = name
        self.file = input_file
        self.lineno = lineno
        self.base = base
        self.fixedbits = fixb
        self.fixedmask = fixm
        self.undefmask = udfm
        self.fieldmask = fldm
        self.fields = flds
        self.width = w

    def __str__(self):
        return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)

    def str1(self, i):
        return str_indent(i) + self.__str__()
# end General


class Format(General):
    """Class representing an instruction format"""

    def extract_name(self):
        global decode_function
        return decode_function + '_extract_' + self.name

    def output_extract(self):
        output('static void ', self.extract_name(), '(DisasContext *ctx, ',
               self.base.struct_name(), ' *a, ', insntype, ' insn)\n{\n')
        for n, f in self.fields.items():
            output('    a->', n, ' = ', f.str_extract(), ';\n')
        output('}\n\n')
# end Format


class Pattern(General):
    """Class representing an instruction pattern"""

    def output_decl(self):
        global translate_scope
        global translate_prefix
        output('typedef ', self.base.base.struct_name(),
               ' arg_', self.name, ';\n')
        output(translate_scope, 'bool ', translate_prefix, '_', self.name,
               '(DisasContext *ctx, arg_', self.name, ' *a);\n')

    def output_code(self, i, extracted, outerbits, outermask):
        global translate_prefix
        ind = str_indent(i)
        arg = self.base.base.name
        output(ind, '/* ', self.file, ':', str(self.lineno), ' */\n')
        if not extracted:
            output(ind, self.base.extract_name(),
                   '(ctx, &u.f_', arg, ', insn);\n')
        for n, f in self.fields.items():
            output(ind, 'u.f_', arg, '.', n, ' = ', f.str_extract(), ';\n')
        output(ind, 'if (', translate_prefix, '_', self.name,
               '(ctx, &u.f_', arg, ')) return true;\n')

    # Normal patterns do not have children.
    def build_tree(self):
        return
    def prop_masks(self):
        return
    def prop_format(self):
        return
    def prop_width(self):
        return

# end Pattern


class MultiPattern(General):
    """Class representing a set of instruction patterns"""

    def __init__(self, lineno):
        self.file = input_file
        self.lineno = lineno
        self.pats = []
        self.base = None
        self.fixedbits = 0
        self.fixedmask = 0
        self.undefmask = 0
        self.width = None

    def __str__(self):
        r = 'group'
        if self.fixedbits is not None:
            r += ' ' + str_match_bits(self.fixedbits, self.fixedmask)
        return r

    def output_decl(self):
        for p in self.pats:
            p.output_decl()

    def prop_masks(self):
        global insnmask

        fixedmask = insnmask
        undefmask = insnmask

        # Collect fixedmask/undefmask for all of the children.
        for p in self.pats:
            p.prop_masks()
            fixedmask &= p.fixedmask
            undefmask &= p.undefmask

        # Widen fixedmask until all fixedbits match
        repeat = True
        fixedbits = 0
        while repeat and fixedmask != 0:
            fixedbits = None
            for p in self.pats:
                thisbits = p.fixedbits & fixedmask
                if fixedbits is None:
                    fixedbits = thisbits
                elif fixedbits != thisbits:
                    fixedmask &= ~(fixedbits ^ thisbits)
                    break
            else:
                repeat = False

        self.fixedbits = fixedbits
        self.fixedmask = fixedmask
        self.undefmask = undefmask

    def build_tree(self):
        for p in self.pats:
            p.build_tree()

    def prop_format(self):
        for p in self.pats:
            p.build_tree()

    def prop_width(self):
        width = None
        for p in self.pats:
            p.prop_width()
            if width is None:
                width = p.width
            elif width != p.width:
                error_with_file(self.file, self.lineno,
                                'width mismatch in patterns within braces')
        self.width = width

# end MultiPattern


class IncMultiPattern(MultiPattern):
    """Class representing an overlapping set of instruction patterns"""

    def output_code(self, i, extracted, outerbits, outermask):
        global translate_prefix
        ind = str_indent(i)
        for p in self.pats:
            if outermask != p.fixedmask:
                innermask = p.fixedmask & ~outermask
                innerbits = p.fixedbits & ~outermask
                output(ind, 'if ((insn & ',
                       '0x{0:08x}) == 0x{1:08x}'.format(innermask, innerbits),
                       ') {\n')
                output(ind, '    /* ',
                       str_match_bits(p.fixedbits, p.fixedmask), ' */\n')
                p.output_code(i + 4, extracted, p.fixedbits, p.fixedmask)
                output(ind, '}\n')
            else:
                p.output_code(i, extracted, p.fixedbits, p.fixedmask)
#end IncMultiPattern


class Tree:
    """Class representing a node in a decode tree"""

    def __init__(self, fm, tm):
        self.fixedmask = fm
        self.thismask = tm
        self.subs = []
        self.base = None

    def str1(self, i):
        ind = str_indent(i)
        r = '{0}{1:08x}'.format(ind, self.fixedmask)
        if self.format:
            r += ' ' + self.format.name
        r += ' [\n'
        for (b, s) in self.subs:
            r += '{0}  {1:08x}:\n'.format(ind, b)
            r += s.str1(i + 4) + '\n'
        r += ind + ']'
        return r

    def __str__(self):
        return self.str1(0)

    def output_code(self, i, extracted, outerbits, outermask):
        ind = str_indent(i)

        # If we identified all nodes below have the same format,
        # extract the fields now.
        if not extracted and self.base:
            output(ind, self.base.extract_name(),
                   '(ctx, &u.f_', self.base.base.name, ', insn);\n')
            extracted = True

        # Attempt to aid the compiler in producing compact switch statements.
        # If the bits in the mask are contiguous, extract them.
        sh = is_contiguous(self.thismask)
        if sh > 0:
            # Propagate SH down into the local functions.
            def str_switch(b, sh=sh):
                return '(insn >> {0}) & 0x{1:x}'.format(sh, b >> sh)

            def str_case(b, sh=sh):
                return '0x{0:x}'.format(b >> sh)
        else:
            def str_switch(b):
                return 'insn & 0x{0:08x}'.format(b)

            def str_case(b):
                return '0x{0:08x}'.format(b)

        output(ind, 'switch (', str_switch(self.thismask), ') {\n')
        for b, s in sorted(self.subs):
            assert (self.thismask & ~s.fixedmask) == 0
            innermask = outermask | self.thismask
            innerbits = outerbits | b
            output(ind, 'case ', str_case(b), ':\n')
            output(ind, '    /* ',
                   str_match_bits(innerbits, innermask), ' */\n')
            s.output_code(i + 4, extracted, innerbits, innermask)
            output(ind, '    break;\n')
        output(ind, '}\n')
# end Tree


class ExcMultiPattern(MultiPattern):
    """Class representing a non-overlapping set of instruction patterns"""

    def output_code(self, i, extracted, outerbits, outermask):
        # Defer everything to our decomposed Tree node
        self.tree.output_code(i, extracted, outerbits, outermask)

    @staticmethod
    def __build_tree(pats, outerbits, outermask):
        # Find the intersection of all remaining fixedmask.
        innermask = ~outermask & insnmask
        for i in pats:
            innermask &= i.fixedmask

        if innermask == 0:
            # Edge condition: One pattern covers the entire insnmask
            if len(pats) == 1:
                t = Tree(outermask, innermask)
                t.subs.append((0, pats[0]))
                return t

            text = 'overlapping patterns:'
            for p in pats:
                text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
            error_with_file(pats[0].file, pats[0].lineno, text)

        fullmask = outermask | innermask

        # Sort each element of pats into the bin selected by the mask.
        bins = {}
        for i in pats:
            fb = i.fixedbits & innermask
            if fb in bins:
                bins[fb].append(i)
            else:
                bins[fb] = [i]

        # We must recurse if any bin has more than one element or if
        # the single element in the bin has not been fully matched.
        t = Tree(fullmask, innermask)

        for b, l in bins.items():
            s = l[0]
            if len(l) > 1 or s.fixedmask & ~fullmask != 0:
                s = ExcMultiPattern.__build_tree(l, b | outerbits, fullmask)
            t.subs.append((b, s))

        return t

    def build_tree(self):
        super().prop_format()
        self.tree = self.__build_tree(self.pats, self.fixedbits,
                                      self.fixedmask)

    @staticmethod
    def __prop_format(tree):
        """Propagate Format objects into the decode tree"""

        # Depth first search.
        for (b, s) in tree.subs:
            if isinstance(s, Tree):
                ExcMultiPattern.__prop_format(s)

        # If all entries in SUBS have the same format, then
        # propagate that into the tree.
        f = None
        for (b, s) in tree.subs:
            if f is None:
                f = s.base
                if f is None:
                    return
            if f is not s.base:
                return
        tree.base = f

    def prop_format(self):
        super().prop_format()
        self.__prop_format(self.tree)

# end ExcMultiPattern


def parse_field(lineno, name, toks):
    """Parse one instruction field from TOKS at LINENO"""
    global fields
    global insnwidth

    # A "simple" field will have only one entry;
    # a "multifield" will have several.
    subs = []
    width = 0
    func = None
    for t in toks:
        if re.match('^!function=', t):
            if func:
                error(lineno, 'duplicate function')
            func = t.split('=')
            func = func[1]
            continue

        if re.fullmatch('[0-9]+:s[0-9]+', t):
            # Signed field extract
            subtoks = t.split(':s')
            sign = True
        elif re.fullmatch('[0-9]+:[0-9]+', t):
            # Unsigned field extract
            subtoks = t.split(':')
            sign = False
        else:
            error(lineno, 'invalid field token "{0}"'.format(t))
        po = int(subtoks[0])
        le = int(subtoks[1])
        if po + le > insnwidth:
            error(lineno, 'field {0} too large'.format(t))
        f = Field(sign, po, le)
        subs.append(f)
        width += le

    if width > insnwidth:
        error(lineno, 'field too large')
    if len(subs) == 0:
        if func:
            f = ParameterField(func)
        else:
            error(lineno, 'field with no value')
    else:
        if len(subs) == 1:
            f = subs[0]
        else:
            mask = 0
            for s in subs:
                if mask & s.mask:
                    error(lineno, 'field components overlap')
                mask |= s.mask
            f = MultiField(subs, mask)
        if func:
            f = FunctionField(func, f)

    if name in fields:
        error(lineno, 'duplicate field', name)
    fields[name] = f
# end parse_field


def parse_arguments(lineno, name, toks):
    """Parse one argument set from TOKS at LINENO"""
    global arguments
    global re_C_ident
    global anyextern

    flds = []
    extern = False
    for t in toks:
        if re.fullmatch('!extern', t):
            extern = True
            anyextern = True
            continue
        if not re.fullmatch(re_C_ident, t):
            error(lineno, 'invalid argument set token "{0}"'.format(t))
        if t in flds:
            error(lineno, 'duplicate argument "{0}"'.format(t))
        flds.append(t)

    if name in arguments:
        error(lineno, 'duplicate argument set', name)
    arguments[name] = Arguments(name, flds, extern)
# end parse_arguments


def lookup_field(lineno, name):
    global fields
    if name in fields:
        return fields[name]
    error(lineno, 'undefined field', name)


def add_field(lineno, flds, new_name, f):
    if new_name in flds:
        error(lineno, 'duplicate field', new_name)
    flds[new_name] = f
    return flds


def add_field_byname(lineno, flds, new_name, old_name):
    return add_field(lineno, flds, new_name, lookup_field(lineno, old_name))


def infer_argument_set(flds):
    global arguments
    global decode_function

    for arg in arguments.values():
        if eq_fields_for_args(flds, arg.fields):
            return arg

    name = decode_function + str(len(arguments))
    arg = Arguments(name, flds.keys(), False)
    arguments[name] = arg
    return arg


def infer_format(arg, fieldmask, flds, width):
    global arguments
    global formats
    global decode_function

    const_flds = {}
    var_flds = {}
    for n, c in flds.items():
        if c is ConstField:
            const_flds[n] = c
        else:
            var_flds[n] = c

    # Look for an existing format with the same argument set and fields
    for fmt in formats.values():
        if arg and fmt.base != arg:
            continue
        if fieldmask != fmt.fieldmask:
            continue
        if width != fmt.width:
            continue
        if not eq_fields_for_fmts(flds, fmt.fields):
            continue
        return (fmt, const_flds)

    name = decode_function + '_Fmt_' + str(len(formats))
    if not arg:
        arg = infer_argument_set(flds)

    fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds, width)
    formats[name] = fmt

    return (fmt, const_flds)
# end infer_format


def parse_generic(lineno, parent_pat, name, toks):
    """Parse one instruction format from TOKS at LINENO"""
    global fields
    global arguments
    global formats
    global allpatterns
    global re_arg_ident
    global re_fld_ident
    global re_fmt_ident
    global re_C_ident
    global insnwidth
    global insnmask
    global variablewidth

    is_format = parent_pat is None

    fixedmask = 0
    fixedbits = 0
    undefmask = 0
    width = 0
    flds = {}
    arg = None
    fmt = None
    for t in toks:
        # '&Foo' gives a format an explicit argument set.
        if re.fullmatch(re_arg_ident, t):
            tt = t[1:]
            if arg:
                error(lineno, 'multiple argument sets')
            if tt in arguments:
                arg = arguments[tt]
            else:
                error(lineno, 'undefined argument set', t)
            continue

        # '@Foo' gives a pattern an explicit format.
        if re.fullmatch(re_fmt_ident, t):
            tt = t[1:]
            if fmt:
                error(lineno, 'multiple formats')
            if tt in formats:
                fmt = formats[tt]
            else:
                error(lineno, 'undefined format', t)
            continue

        # '%Foo' imports a field.
        if re.fullmatch(re_fld_ident, t):
            tt = t[1:]
            flds = add_field_byname(lineno, flds, tt, tt)
            continue

        # 'Foo=%Bar' imports a field with a different name.
        if re.fullmatch(re_C_ident + '=' + re_fld_ident, t):
            (fname, iname) = t.split('=%')
            flds = add_field_byname(lineno, flds, fname, iname)
            continue

        # 'Foo=number' sets an argument field to a constant value
        if re.fullmatch(re_C_ident + '=[+-]?[0-9]+', t):
            (fname, value) = t.split('=')
            value = int(value)
            flds = add_field(lineno, flds, fname, ConstField(value))
            continue

        # Pattern of 0s, 1s, dots and dashes indicate required zeros,
        # required ones, or dont-cares.
        if re.fullmatch('[01.-]+', t):
            shift = len(t)
            fms = t.replace('0', '1')
            fms = fms.replace('.', '0')
            fms = fms.replace('-', '0')
            fbs = t.replace('.', '0')
            fbs = fbs.replace('-', '0')
            ubm = t.replace('1', '0')
            ubm = ubm.replace('.', '0')
            ubm = ubm.replace('-', '1')
            fms = int(fms, 2)
            fbs = int(fbs, 2)
            ubm = int(ubm, 2)
            fixedbits = (fixedbits << shift) | fbs
            fixedmask = (fixedmask << shift) | fms
            undefmask = (undefmask << shift) | ubm
        # Otherwise, fieldname:fieldwidth
        elif re.fullmatch(re_C_ident + ':s?[0-9]+', t):
            (fname, flen) = t.split(':')
            sign = False
            if flen[0] == 's':
                sign = True
                flen = flen[1:]
            shift = int(flen, 10)
            if shift + width > insnwidth:
                error(lineno, 'field {0} exceeds insnwidth'.format(fname))
            f = Field(sign, insnwidth - width - shift, shift)
            flds = add_field(lineno, flds, fname, f)
            fixedbits <<= shift
            fixedmask <<= shift
            undefmask <<= shift
        else:
            error(lineno, 'invalid token "{0}"'.format(t))
        width += shift

    if variablewidth and width < insnwidth and width % 8 == 0:
        shift = insnwidth - width
        fixedbits <<= shift
        fixedmask <<= shift
        undefmask <<= shift
        undefmask |= (1 << shift) - 1

    # We should have filled in all of the bits of the instruction.
    elif not (is_format and width == 0) and width != insnwidth:
        error(lineno, 'definition has {0} bits'.format(width))

    # Do not check for fields overlapping fields; one valid usage
    # is to be able to duplicate fields via import.
    fieldmask = 0
    for f in flds.values():
        fieldmask |= f.mask

    # Fix up what we've parsed to match either a format or a pattern.
    if is_format:
        # Formats cannot reference formats.
        if fmt:
            error(lineno, 'format referencing format')
        # If an argument set is given, then there should be no fields
        # without a place to store it.
        if arg:
            for f in flds.keys():
                if f not in arg.fields:
                    error(lineno, 'field {0} not in argument set {1}'
                                  .format(f, arg.name))
        else:
            arg = infer_argument_set(flds)
        if name in formats:
            error(lineno, 'duplicate format name', name)
        fmt = Format(name, lineno, arg, fixedbits, fixedmask,
                     undefmask, fieldmask, flds, width)
        formats[name] = fmt
    else:
        # Patterns can reference a format ...
        if fmt:
            # ... but not an argument simultaneously
            if arg:
                error(lineno, 'pattern specifies both format and argument set')
            if fixedmask & fmt.fixedmask:
                error(lineno, 'pattern fixed bits overlap format fixed bits')
            if width != fmt.width:
                error(lineno, 'pattern uses format of different width')
            fieldmask |= fmt.fieldmask
            fixedbits |= fmt.fixedbits
            fixedmask |= fmt.fixedmask
            undefmask |= fmt.undefmask
        else:
            (fmt, flds) = infer_format(arg, fieldmask, flds, width)
        arg = fmt.base
        for f in flds.keys():
            if f not in arg.fields:
                error(lineno, 'field {0} not in argument set {1}'
                              .format(f, arg.name))
            if f in fmt.fields.keys():
                error(lineno, 'field {0} set by format and pattern'.format(f))
        for f in arg.fields:
            if f not in flds.keys() and f not in fmt.fields.keys():
                error(lineno, 'field {0} not initialized'.format(f))
        pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
                      undefmask, fieldmask, flds, width)
        parent_pat.pats.append(pat)
        allpatterns.append(pat)

    # Validate the masks that we have assembled.
    if fieldmask & fixedmask:
        error(lineno, 'fieldmask overlaps fixedmask (0x{0:08x} & 0x{1:08x})'
                      .format(fieldmask, fixedmask))
    if fieldmask & undefmask:
        error(lineno, 'fieldmask overlaps undefmask (0x{0:08x} & 0x{1:08x})'
                      .format(fieldmask, undefmask))
    if fixedmask & undefmask:
        error(lineno, 'fixedmask overlaps undefmask (0x{0:08x} & 0x{1:08x})'
                      .format(fixedmask, undefmask))
    if not is_format:
        allbits = fieldmask | fixedmask | undefmask
        if allbits != insnmask:
            error(lineno, 'bits left unspecified (0x{0:08x})'
                          .format(allbits ^ insnmask))
# end parse_general


def parse_file(f, parent_pat):
    """Parse all of the patterns within a file"""
    global re_arg_ident
    global re_fld_ident
    global re_fmt_ident
    global re_pat_ident

    # Read all of the lines of the file.  Concatenate lines
    # ending in backslash; discard empty lines and comments.
    toks = []
    lineno = 0
    nesting = 0
    nesting_pats = []

    for line in f:
        lineno += 1

        # Expand and strip spaces, to find indent.
        line = line.rstrip()
        line = line.expandtabs()
        len1 = len(line)
        line = line.lstrip()
        len2 = len(line)

        # Discard comments
        end = line.find('#')
        if end >= 0:
            line = line[:end]

        t = line.split()
        if len(toks) != 0:
            # Next line after continuation
            toks.extend(t)
        else:
            # Allow completely blank lines.
            if len1 == 0:
                continue
            indent = len1 - len2
            # Empty line due to comment.
            if len(t) == 0:
                # Indentation must be correct, even for comment lines.
                if indent != nesting:
                    error(lineno, 'indentation ', indent, ' != ', nesting)
                continue
            start_lineno = lineno
            toks = t

        # Continuation?
        if toks[-1] == '\\':
            toks.pop()
            continue

        name = toks[0]
        del toks[0]

        # End nesting?
        if name == '}' or name == ']':
            if len(toks) != 0:
                error(start_lineno, 'extra tokens after close brace')

            # Make sure { } and [ ] nest properly.
            if (name == '}') != isinstance(parent_pat, IncMultiPattern):
                error(lineno, 'mismatched close brace')

            try:
                parent_pat = nesting_pats.pop()
            except:
                error(lineno, 'extra close brace')

            nesting -= 2
            if indent != nesting:
                error(lineno, 'indentation ', indent, ' != ', nesting)

            toks = []
            continue

        # Everything else should have current indentation.
        if indent != nesting:
            error(start_lineno, 'indentation ', indent, ' != ', nesting)

        # Start nesting?
        if name == '{' or name == '[':
            if len(toks) != 0:
                error(start_lineno, 'extra tokens after open brace')

            if name == '{':
                nested_pat = IncMultiPattern(start_lineno)
            else:
                nested_pat = ExcMultiPattern(start_lineno)
            parent_pat.pats.append(nested_pat)
            nesting_pats.append(parent_pat)
            parent_pat = nested_pat

            nesting += 2
            toks = []
            continue

        # Determine the type of object needing to be parsed.
        if re.fullmatch(re_fld_ident, name):
            parse_field(start_lineno, name[1:], toks)
        elif re.fullmatch(re_arg_ident, name):
            parse_arguments(start_lineno, name[1:], toks)
        elif re.fullmatch(re_fmt_ident, name):
            parse_generic(start_lineno, None, name[1:], toks)
        elif re.fullmatch(re_pat_ident, name):
            parse_generic(start_lineno, parent_pat, name, toks)
        else:
            error(lineno, 'invalid token "{0}"'.format(name))
        toks = []

    if nesting != 0:
        error(lineno, 'missing close brace')
# end parse_file


class SizeTree:
    """Class representing a node in a size decode tree"""

    def __init__(self, m, w):
        self.mask = m
        self.subs = []
        self.base = None
        self.width = w

    def str1(self, i):
        ind = str_indent(i)
        r = '{0}{1:08x}'.format(ind, self.mask)
        r += ' [\n'
        for (b, s) in self.subs:
            r += '{0}  {1:08x}:\n'.format(ind, b)
            r += s.str1(i + 4) + '\n'
        r += ind + ']'
        return r

    def __str__(self):
        return self.str1(0)

    def output_code(self, i, extracted, outerbits, outermask):
        ind = str_indent(i)

        # If we need to load more bytes to test, do so now.
        if extracted < self.width:
            output(ind, 'insn = ', decode_function,
                   '_load_bytes(ctx, insn, {0}, {1});\n'
                   .format(extracted // 8, self.width // 8));
            extracted = self.width

        # Attempt to aid the compiler in producing compact switch statements.
        # If the bits in the mask are contiguous, extract them.
        sh = is_contiguous(self.mask)
        if sh > 0:
            # Propagate SH down into the local functions.
            def str_switch(b, sh=sh):
                return '(insn >> {0}) & 0x{1:x}'.format(sh, b >> sh)

            def str_case(b, sh=sh):
                return '0x{0:x}'.format(b >> sh)
        else:
            def str_switch(b):
                return 'insn & 0x{0:08x}'.format(b)

            def str_case(b):
                return '0x{0:08x}'.format(b)

        output(ind, 'switch (', str_switch(self.mask), ') {\n')
        for b, s in sorted(self.subs):
            innermask = outermask | self.mask
            innerbits = outerbits | b
            output(ind, 'case ', str_case(b), ':\n')
            output(ind, '    /* ',
                   str_match_bits(innerbits, innermask), ' */\n')
            s.output_code(i + 4, extracted, innerbits, innermask)
        output(ind, '}\n')
        output(ind, 'return insn;\n')
# end SizeTree

class SizeLeaf:
    """Class representing a leaf node in a size decode tree"""

    def __init__(self, m, w):
        self.mask = m
        self.width = w

    def str1(self, i):
        ind = str_indent(i)
        return '{0}{1:08x}'.format(ind, self.mask)

    def __str__(self):
        return self.str1(0)

    def output_code(self, i, extracted, outerbits, outermask):
        global decode_function
        ind = str_indent(i)

        # If we need to load more bytes, do so now.
        if extracted < self.width:
            output(ind, 'insn = ', decode_function,
                   '_load_bytes(ctx, insn, {0}, {1});\n'
                   .format(extracted // 8, self.width // 8));
            extracted = self.width
        output(ind, 'return insn;\n')
# end SizeLeaf


def build_size_tree(pats, width, outerbits, outermask):
    global insnwidth

    # Collect the mask of bits that are fixed in this width
    innermask = 0xff << (insnwidth - width)
    innermask &= ~outermask
    minwidth = None
    onewidth = True
    for i in pats:
        innermask &= i.fixedmask
        if minwidth is None:
            minwidth = i.width
        elif minwidth != i.width:
            onewidth = False;
            if minwidth < i.width:
                minwidth = i.width

    if onewidth:
        return SizeLeaf(innermask, minwidth)

    if innermask == 0:
        if width < minwidth:
            return build_size_tree(pats, width + 8, outerbits, outermask)

        pnames = []
        for p in pats:
            pnames.append(p.name + ':' + p.file + ':' + str(p.lineno))
        error_with_file(pats[0].file, pats[0].lineno,
                        'overlapping patterns size {0}:'.format(width), pnames)

    bins = {}
    for i in pats:
        fb = i.fixedbits & innermask
        if fb in bins:
            bins[fb].append(i)
        else:
            bins[fb] = [i]

    fullmask = outermask | innermask
    lens = sorted(bins.keys())
    if len(lens) == 1:
        b = lens[0]
        return build_size_tree(bins[b], width + 8, b | outerbits, fullmask)

    r = SizeTree(innermask, width)
    for b, l in bins.items():
        s = build_size_tree(l, width, b | outerbits, fullmask)
        r.subs.append((b, s))
    return r
# end build_size_tree


def prop_size(tree):
    """Propagate minimum widths up the decode size tree"""

    if isinstance(tree, SizeTree):
        min = None
        for (b, s) in tree.subs:
            width = prop_size(s)
            if min is None or min > width:
                min = width
        assert min >= tree.width
        tree.width = min
    else:
        min = tree.width
    return min
# end prop_size


def main():
    global arguments
    global formats
    global allpatterns
    global translate_scope
    global translate_prefix
    global output_fd
    global output_file
    global input_file
    global insnwidth
    global insntype
    global insnmask
    global decode_function
    global variablewidth
    global anyextern

    decode_scope = 'static '

    long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=',
                 'static-decode=', 'varinsnwidth=']
    try:
        (opts, args) = getopt.gnu_getopt(sys.argv[1:], 'o:vw:', long_opts)
    except getopt.GetoptError as err:
        error(0, err)
    for o, a in opts:
        if o in ('-o', '--output'):
            output_file = a
        elif o == '--decode':
            decode_function = a
            decode_scope = ''
        elif o == '--static-decode':
            decode_function = a
        elif o == '--translate':
            translate_prefix = a
            translate_scope = ''
        elif o in ('-w', '--insnwidth', '--varinsnwidth'):
            if o == '--varinsnwidth':
                variablewidth = True
            insnwidth = int(a)
            if insnwidth == 16:
                insntype = 'uint16_t'
                insnmask = 0xffff
            elif insnwidth != 32:
                error(0, 'cannot handle insns of width', insnwidth)
        else:
            assert False, 'unhandled option'

    if len(args) < 1:
        error(0, 'missing input file')

    toppat = ExcMultiPattern(0)

    for filename in args:
        input_file = filename
        f = open(filename, 'r')
        parse_file(f, toppat)
        f.close()

    # We do not want to compute masks for toppat, because those masks
    # are used as a starting point for build_tree.  For toppat, we must
    # insist that decode begins from naught.
    for i in toppat.pats:
        i.prop_masks()

    toppat.build_tree()
    toppat.prop_format()

    if variablewidth:
        for i in toppat.pats:
            i.prop_width()
        stree = build_size_tree(toppat.pats, 8, 0, 0)
        prop_size(stree)

    if output_file:
        output_fd = open(output_file, 'w')
    else:
        output_fd = sys.stdout

    output_autogen()
    for n in sorted(arguments.keys()):
        f = arguments[n]
        f.output_def()

    # A single translate function can be invoked for different patterns.
    # Make sure that the argument sets are the same, and declare the
    # function only once.
    #
    # If we're sharing formats, we're likely also sharing trans_* functions,
    # but we can't tell which ones.  Prevent issues from the compiler by
    # suppressing redundant declaration warnings.
    if anyextern:
        output("#pragma GCC diagnostic push\n",
               "#pragma GCC diagnostic ignored \"-Wredundant-decls\"\n",
               "#ifdef __clang__\n"
               "#  pragma GCC diagnostic ignored \"-Wtypedef-redefinition\"\n",
               "#endif\n\n")

    out_pats = {}
    for i in allpatterns:
        if i.name in out_pats:
            p = out_pats[i.name]
            if i.base.base != p.base.base:
                error(0, i.name, ' has conflicting argument sets')
        else:
            i.output_decl()
            out_pats[i.name] = i
    output('\n')

    if anyextern:
        output("#pragma GCC diagnostic pop\n\n")

    for n in sorted(formats.keys()):
        f = formats[n]
        f.output_extract()

    output(decode_scope, 'bool ', decode_function,
           '(DisasContext *ctx, ', insntype, ' insn)\n{\n')

    i4 = str_indent(4)

    if len(allpatterns) != 0:
        output(i4, 'union {\n')
        for n in sorted(arguments.keys()):
            f = arguments[n]
            output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
        output(i4, '} u;\n\n')
        toppat.output_code(4, False, 0, 0)

    output(i4, 'return false;\n')
    output('}\n')

    if variablewidth:
        output('\n', decode_scope, insntype, ' ', decode_function,
               '_load(DisasContext *ctx)\n{\n',
               '    ', insntype, ' insn = 0;\n\n')
        stree.output_code(4, 0, 0, 0)
        output('}\n')

    if output_file:
        output_fd.close()
# end main


if __name__ == '__main__':
    main()