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
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
|
/* Parse expressions for GDB.
Copyright (C) 1986-2021 Free Software Foundation, Inc.
Modified from expread.y by the Department of Computer Science at the
State University of New York at Buffalo, 1991.
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 3 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, see <http://www.gnu.org/licenses/>. */
/* Parse an expression from text in a string,
and return the result as a struct expression pointer.
That structure contains arithmetic operations in reverse polish,
with constants represented by operations that are followed by special data.
See expression.h for the details of the format.
What is important here is that it can be built up sequentially
during the process of parsing; the lower levels of the tree always
come first in the result. */
#include "defs.h"
#include <ctype.h>
#include "arch-utils.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "frame.h"
#include "expression.h"
#include "value.h"
#include "command.h"
#include "language.h"
#include "parser-defs.h"
#include "gdbcmd.h"
#include "symfile.h" /* for overlay functions */
#include "inferior.h"
#include "target-float.h"
#include "block.h"
#include "source.h"
#include "objfiles.h"
#include "user-regs.h"
#include <algorithm>
#include "gdbsupport/gdb_optional.h"
#include "c-exp.h"
/* Standard set of definitions for printing, dumping, prefixifying,
* and evaluating expressions. */
const struct exp_descriptor exp_descriptor_standard =
{
print_subexp_standard,
operator_length_standard,
operator_check_standard,
dump_subexp_body_standard,
evaluate_subexp_standard
};
static unsigned int expressiondebug = 0;
static void
show_expressiondebug (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Expression debugging is %s.\n"), value);
}
/* True if an expression parser should set yydebug. */
bool parser_debug;
static void
show_parserdebug (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Parser debugging is %s.\n"), value);
}
static int prefixify_subexp (struct expression *, struct expression *, int,
int, int);
static expression_up parse_exp_in_context (const char **, CORE_ADDR,
const struct block *, int,
bool, int *,
innermost_block_tracker *,
expr_completion_state *);
static void increase_expout_size (struct expr_builder *ps, size_t lenelt);
/* Documented at it's declaration. */
void
innermost_block_tracker::update (const struct block *b,
innermost_block_tracker_types t)
{
if ((m_types & t) != 0
&& (m_innermost_block == NULL
|| contained_in (b, m_innermost_block)))
m_innermost_block = b;
}
/* See definition in parser-defs.h. */
expr_builder::expr_builder (const struct language_defn *lang,
struct gdbarch *gdbarch)
: expout_size (10),
expout (new expression (lang, gdbarch, expout_size)),
expout_ptr (0)
{
}
expression_up
expr_builder::release ()
{
/* Record the actual number of expression elements, and then
reallocate the expression memory so that we free up any
excess elements. */
expout->nelts = expout_ptr;
expout->resize (expout_ptr);
return std::move (expout);
}
expression::expression (const struct language_defn *lang, struct gdbarch *arch,
size_t n)
: language_defn (lang),
gdbarch (arch),
elts (nullptr)
{
resize (n);
}
expression::~expression ()
{
xfree (elts);
}
void
expression::resize (size_t n)
{
elts = XRESIZEVAR (union exp_element, elts, EXP_ELEM_TO_BYTES (n));
}
/* This page contains the functions for adding data to the struct expression
being constructed. */
/* Add one element to the end of the expression. */
/* To avoid a bug in the Sun 4 compiler, we pass things that can fit into
a register through here. */
static void
write_exp_elt (struct expr_builder *ps, const union exp_element *expelt)
{
if (ps->expout_ptr >= ps->expout_size)
{
ps->expout_size *= 2;
ps->expout->resize (ps->expout_size);
}
ps->expout->elts[ps->expout_ptr++] = *expelt;
}
void
write_exp_elt_opcode (struct expr_builder *ps, enum exp_opcode expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.opcode = expelt;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_sym (struct expr_builder *ps, struct symbol *expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.symbol = expelt;
write_exp_elt (ps, &tmp);
}
static void
write_exp_elt_msym (struct expr_builder *ps, minimal_symbol *expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.msymbol = expelt;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_block (struct expr_builder *ps, const struct block *b)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.block = b;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_objfile (struct expr_builder *ps, struct objfile *objfile)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.objfile = objfile;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_longcst (struct expr_builder *ps, LONGEST expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.longconst = expelt;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_floatcst (struct expr_builder *ps, const gdb_byte expelt[16])
{
union exp_element tmp;
int index;
for (index = 0; index < 16; index++)
tmp.floatconst[index] = expelt[index];
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_type (struct expr_builder *ps, struct type *expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.type = expelt;
write_exp_elt (ps, &tmp);
}
void
write_exp_elt_intern (struct expr_builder *ps, struct internalvar *expelt)
{
union exp_element tmp;
memset (&tmp, 0, sizeof (union exp_element));
tmp.internalvar = expelt;
write_exp_elt (ps, &tmp);
}
/* Add a string constant to the end of the expression.
String constants are stored by first writing an expression element
that contains the length of the string, then stuffing the string
constant itself into however many expression elements are needed
to hold it, and then writing another expression element that contains
the length of the string. I.e. an expression element at each end of
the string records the string length, so you can skip over the
expression elements containing the actual string bytes from either
end of the string. Note that this also allows gdb to handle
strings with embedded null bytes, as is required for some languages.
Don't be fooled by the fact that the string is null byte terminated,
this is strictly for the convenience of debugging gdb itself.
Gdb does not depend up the string being null terminated, since the
actual length is recorded in expression elements at each end of the
string. The null byte is taken into consideration when computing how
many expression elements are required to hold the string constant, of
course. */
void
write_exp_string (struct expr_builder *ps, struct stoken str)
{
int len = str.length;
size_t lenelt;
char *strdata;
/* Compute the number of expression elements required to hold the string
(including a null byte terminator), along with one expression element
at each end to record the actual string length (not including the
null byte terminator). */
lenelt = 2 + BYTES_TO_EXP_ELEM (len + 1);
increase_expout_size (ps, lenelt);
/* Write the leading length expression element (which advances the current
expression element index), then write the string constant followed by a
terminating null byte, and then write the trailing length expression
element. */
write_exp_elt_longcst (ps, (LONGEST) len);
strdata = (char *) &ps->expout->elts[ps->expout_ptr];
memcpy (strdata, str.ptr, len);
*(strdata + len) = '\0';
ps->expout_ptr += lenelt - 2;
write_exp_elt_longcst (ps, (LONGEST) len);
}
/* Add a vector of string constants to the end of the expression.
This adds an OP_STRING operation, but encodes the contents
differently from write_exp_string. The language is expected to
handle evaluation of this expression itself.
After the usual OP_STRING header, TYPE is written into the
expression as a long constant. The interpretation of this field is
up to the language evaluator.
Next, each string in VEC is written. The length is written as a
long constant, followed by the contents of the string. */
void
write_exp_string_vector (struct expr_builder *ps, int type,
struct stoken_vector *vec)
{
int i, len;
size_t n_slots;
/* Compute the size. We compute the size in number of slots to
avoid issues with string padding. */
n_slots = 0;
for (i = 0; i < vec->len; ++i)
{
/* One slot for the length of this element, plus the number of
slots needed for this string. */
n_slots += 1 + BYTES_TO_EXP_ELEM (vec->tokens[i].length);
}
/* One more slot for the type of the string. */
++n_slots;
/* Now compute a phony string length. */
len = EXP_ELEM_TO_BYTES (n_slots) - 1;
n_slots += 4;
increase_expout_size (ps, n_slots);
write_exp_elt_opcode (ps, OP_STRING);
write_exp_elt_longcst (ps, len);
write_exp_elt_longcst (ps, type);
for (i = 0; i < vec->len; ++i)
{
write_exp_elt_longcst (ps, vec->tokens[i].length);
memcpy (&ps->expout->elts[ps->expout_ptr], vec->tokens[i].ptr,
vec->tokens[i].length);
ps->expout_ptr += BYTES_TO_EXP_ELEM (vec->tokens[i].length);
}
write_exp_elt_longcst (ps, len);
write_exp_elt_opcode (ps, OP_STRING);
}
/* Add a bitstring constant to the end of the expression.
Bitstring constants are stored by first writing an expression element
that contains the length of the bitstring (in bits), then stuffing the
bitstring constant itself into however many expression elements are
needed to hold it, and then writing another expression element that
contains the length of the bitstring. I.e. an expression element at
each end of the bitstring records the bitstring length, so you can skip
over the expression elements containing the actual bitstring bytes from
either end of the bitstring. */
void
write_exp_bitstring (struct expr_builder *ps, struct stoken str)
{
int bits = str.length; /* length in bits */
int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
size_t lenelt;
char *strdata;
/* Compute the number of expression elements required to hold the bitstring,
along with one expression element at each end to record the actual
bitstring length in bits. */
lenelt = 2 + BYTES_TO_EXP_ELEM (len);
increase_expout_size (ps, lenelt);
/* Write the leading length expression element (which advances the current
expression element index), then write the bitstring constant, and then
write the trailing length expression element. */
write_exp_elt_longcst (ps, (LONGEST) bits);
strdata = (char *) &ps->expout->elts[ps->expout_ptr];
memcpy (strdata, str.ptr, len);
ps->expout_ptr += lenelt - 2;
write_exp_elt_longcst (ps, (LONGEST) bits);
}
/* Return the type of MSYMBOL, a minimal symbol of OBJFILE. If
ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
address. */
type *
find_minsym_type_and_address (minimal_symbol *msymbol,
struct objfile *objfile,
CORE_ADDR *address_p)
{
bound_minimal_symbol bound_msym = {msymbol, objfile};
struct obj_section *section = msymbol->obj_section (objfile);
enum minimal_symbol_type type = MSYMBOL_TYPE (msymbol);
bool is_tls = (section != NULL
&& section->the_bfd_section->flags & SEC_THREAD_LOCAL);
/* The minimal symbol might point to a function descriptor;
resolve it to the actual code address instead. */
CORE_ADDR addr;
if (is_tls)
{
/* Addresses of TLS symbols are really offsets into a
per-objfile/per-thread storage block. */
addr = MSYMBOL_VALUE_RAW_ADDRESS (bound_msym.minsym);
}
else if (msymbol_is_function (objfile, msymbol, &addr))
{
if (addr != BMSYMBOL_VALUE_ADDRESS (bound_msym))
{
/* This means we resolved a function descriptor, and we now
have an address for a code/text symbol instead of a data
symbol. */
if (MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
type = mst_text_gnu_ifunc;
else
type = mst_text;
section = NULL;
}
}
else
addr = BMSYMBOL_VALUE_ADDRESS (bound_msym);
if (overlay_debugging)
addr = symbol_overlayed_address (addr, section);
if (is_tls)
{
/* Skip translation if caller does not need the address. */
if (address_p != NULL)
*address_p = target_translate_tls_address (objfile, addr);
return objfile_type (objfile)->nodebug_tls_symbol;
}
if (address_p != NULL)
*address_p = addr;
switch (type)
{
case mst_text:
case mst_file_text:
case mst_solib_trampoline:
return objfile_type (objfile)->nodebug_text_symbol;
case mst_text_gnu_ifunc:
return objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
case mst_data:
case mst_file_data:
case mst_bss:
case mst_file_bss:
return objfile_type (objfile)->nodebug_data_symbol;
case mst_slot_got_plt:
return objfile_type (objfile)->nodebug_got_plt_symbol;
default:
return objfile_type (objfile)->nodebug_unknown_symbol;
}
}
/* Add the appropriate elements for a minimal symbol to the end of
the expression. */
void
write_exp_msymbol (struct expr_builder *ps,
struct bound_minimal_symbol bound_msym)
{
write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
write_exp_elt_objfile (ps, bound_msym.objfile);
write_exp_elt_msym (ps, bound_msym.minsym);
write_exp_elt_opcode (ps, OP_VAR_MSYM_VALUE);
}
/* See parser-defs.h. */
void
parser_state::mark_struct_expression ()
{
gdb_assert (parse_completion
&& (m_completion_state.expout_tag_completion_type
== TYPE_CODE_UNDEF));
m_completion_state.expout_last_struct = expout_ptr;
}
/* Indicate that the current parser invocation is completing a tag.
TAG is the type code of the tag, and PTR and LENGTH represent the
start of the tag name. */
void
parser_state::mark_completion_tag (enum type_code tag, const char *ptr,
int length)
{
gdb_assert (parse_completion
&& (m_completion_state.expout_tag_completion_type
== TYPE_CODE_UNDEF)
&& m_completion_state.expout_completion_name == NULL
&& m_completion_state.expout_last_struct == -1);
gdb_assert (tag == TYPE_CODE_UNION
|| tag == TYPE_CODE_STRUCT
|| tag == TYPE_CODE_ENUM);
m_completion_state.expout_tag_completion_type = tag;
m_completion_state.expout_completion_name.reset (xstrndup (ptr, length));
}
/* Recognize tokens that start with '$'. These include:
$regname A native register name or a "standard
register name".
$variable A convenience variable with a name chosen
by the user.
$digits Value history with index <digits>, starting
from the first value which has index 1.
$$digits Value history with index <digits> relative
to the last value. I.e. $$0 is the last
value, $$1 is the one previous to that, $$2
is the one previous to $$1, etc.
$ | $0 | $$0 The last value in the value history.
$$ An abbreviation for the second to the last
value in the value history, I.e. $$1 */
void
write_dollar_variable (struct parser_state *ps, struct stoken str)
{
struct block_symbol sym;
struct bound_minimal_symbol msym;
struct internalvar *isym = NULL;
std::string copy;
/* Handle the tokens $digits; also $ (short for $0) and $$ (short for $$1)
and $$digits (equivalent to $<-digits> if you could type that). */
int negate = 0;
int i = 1;
/* Double dollar means negate the number and add -1 as well.
Thus $$ alone means -1. */
if (str.length >= 2 && str.ptr[1] == '$')
{
negate = 1;
i = 2;
}
if (i == str.length)
{
/* Just dollars (one or two). */
i = -negate;
goto handle_last;
}
/* Is the rest of the token digits? */
for (; i < str.length; i++)
if (!(str.ptr[i] >= '0' && str.ptr[i] <= '9'))
break;
if (i == str.length)
{
i = atoi (str.ptr + 1 + negate);
if (negate)
i = -i;
goto handle_last;
}
/* Handle tokens that refer to machine registers:
$ followed by a register name. */
i = user_reg_map_name_to_regnum (ps->gdbarch (),
str.ptr + 1, str.length - 1);
if (i >= 0)
goto handle_register;
/* Any names starting with $ are probably debugger internal variables. */
copy = copy_name (str);
isym = lookup_only_internalvar (copy.c_str () + 1);
if (isym)
{
write_exp_elt_opcode (ps, OP_INTERNALVAR);
write_exp_elt_intern (ps, isym);
write_exp_elt_opcode (ps, OP_INTERNALVAR);
return;
}
/* On some systems, such as HP-UX and hppa-linux, certain system routines
have names beginning with $ or $$. Check for those, first. */
sym = lookup_symbol (copy.c_str (), NULL, VAR_DOMAIN, NULL);
if (sym.symbol)
{
write_exp_elt_opcode (ps, OP_VAR_VALUE);
write_exp_elt_block (ps, sym.block);
write_exp_elt_sym (ps, sym.symbol);
write_exp_elt_opcode (ps, OP_VAR_VALUE);
return;
}
msym = lookup_bound_minimal_symbol (copy.c_str ());
if (msym.minsym)
{
write_exp_msymbol (ps, msym);
return;
}
/* Any other names are assumed to be debugger internal variables. */
write_exp_elt_opcode (ps, OP_INTERNALVAR);
write_exp_elt_intern (ps, create_internalvar (copy.c_str () + 1));
write_exp_elt_opcode (ps, OP_INTERNALVAR);
return;
handle_last:
write_exp_elt_opcode (ps, OP_LAST);
write_exp_elt_longcst (ps, (LONGEST) i);
write_exp_elt_opcode (ps, OP_LAST);
return;
handle_register:
write_exp_elt_opcode (ps, OP_REGISTER);
str.length--;
str.ptr++;
write_exp_string (ps, str);
write_exp_elt_opcode (ps, OP_REGISTER);
ps->block_tracker->update (ps->expression_context_block,
INNERMOST_BLOCK_FOR_REGISTERS);
return;
}
/* See parser-defs.h. */
void
write_exp_symbol_reference (struct parser_state *pstate, const char *name,
struct block_symbol sym)
{
if (sym.symbol != nullptr)
{
if (symbol_read_needs_frame (sym.symbol))
pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
}
else
{
struct bound_minimal_symbol msymbol = lookup_bound_minimal_symbol (name);
if (msymbol.minsym != NULL)
write_exp_msymbol (pstate, msymbol);
else if (!have_full_symbols () && !have_partial_symbols ())
error (_("No symbol table is loaded. Use the \"file\" command."));
else
error (_("No symbol \"%s\" in current context."), name);
}
}
const char *
find_template_name_end (const char *p)
{
int depth = 1;
int just_seen_right = 0;
int just_seen_colon = 0;
int just_seen_space = 0;
if (!p || (*p != '<'))
return 0;
while (*++p)
{
switch (*p)
{
case '\'':
case '\"':
case '{':
case '}':
/* In future, may want to allow these?? */
return 0;
case '<':
depth++; /* start nested template */
if (just_seen_colon || just_seen_right || just_seen_space)
return 0; /* but not after : or :: or > or space */
break;
case '>':
if (just_seen_colon || just_seen_right)
return 0; /* end a (nested?) template */
just_seen_right = 1; /* but not after : or :: */
if (--depth == 0) /* also disallow >>, insist on > > */
return ++p; /* if outermost ended, return */
break;
case ':':
if (just_seen_space || (just_seen_colon > 1))
return 0; /* nested class spec coming up */
just_seen_colon++; /* we allow :: but not :::: */
break;
case ' ':
break;
default:
if (!((*p >= 'a' && *p <= 'z') || /* allow token chars */
(*p >= 'A' && *p <= 'Z') ||
(*p >= '0' && *p <= '9') ||
(*p == '_') || (*p == ',') || /* commas for template args */
(*p == '&') || (*p == '*') || /* pointer and ref types */
(*p == '(') || (*p == ')') || /* function types */
(*p == '[') || (*p == ']'))) /* array types */
return 0;
}
if (*p != ' ')
just_seen_space = 0;
if (*p != ':')
just_seen_colon = 0;
if (*p != '>')
just_seen_right = 0;
}
return 0;
}
/* Return a null-terminated temporary copy of the name of a string token.
Tokens that refer to names do so with explicit pointer and length,
so they can share the storage that lexptr is parsing.
When it is necessary to pass a name to a function that expects
a null-terminated string, the substring is copied out
into a separate block of storage. */
std::string
copy_name (struct stoken token)
{
return std::string (token.ptr, token.length);
}
/* See comments on parser-defs.h. */
int
prefixify_expression (struct expression *expr, int last_struct)
{
gdb_assert (expr->nelts > 0);
int len = EXP_ELEM_TO_BYTES (expr->nelts);
struct expression temp (expr->language_defn, expr->gdbarch, expr->nelts);
int inpos = expr->nelts, outpos = 0;
/* Copy the original expression into temp. */
memcpy (temp.elts, expr->elts, len);
return prefixify_subexp (&temp, expr, inpos, outpos, last_struct);
}
/* Return the number of exp_elements in the postfix subexpression
of EXPR whose operator is at index ENDPOS - 1 in EXPR. */
static int
length_of_subexp (struct expression *expr, int endpos)
{
int oplen, args;
operator_length (expr, endpos, &oplen, &args);
while (args > 0)
{
oplen += length_of_subexp (expr, endpos - oplen);
args--;
}
return oplen;
}
/* Sets *OPLENP to the length of the operator whose (last) index is
ENDPOS - 1 in EXPR, and sets *ARGSP to the number of arguments that
operator takes. */
void
operator_length (const struct expression *expr, int endpos, int *oplenp,
int *argsp)
{
expr->language_defn->expression_ops ()->operator_length (expr, endpos,
oplenp, argsp);
}
/* Default value for operator_length in exp_descriptor vectors. */
void
operator_length_standard (const struct expression *expr, int endpos,
int *oplenp, int *argsp)
{
int oplen = 1;
int args = 0;
enum range_flag range_flag;
int i;
if (endpos < 1)
error (_("?error in operator_length_standard"));
i = (int) expr->elts[endpos - 1].opcode;
switch (i)
{
/* C++ */
case OP_SCOPE:
oplen = longest_to_int (expr->elts[endpos - 2].longconst);
oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
break;
case OP_LONG:
case OP_FLOAT:
case OP_VAR_VALUE:
case OP_VAR_MSYM_VALUE:
oplen = 4;
break;
case OP_FUNC_STATIC_VAR:
oplen = longest_to_int (expr->elts[endpos - 2].longconst);
oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
args = 1;
break;
case OP_TYPE:
case OP_BOOL:
case OP_LAST:
case OP_INTERNALVAR:
case OP_VAR_ENTRY_VALUE:
oplen = 3;
break;
case OP_COMPLEX:
oplen = 3;
args = 2;
break;
case OP_FUNCALL:
oplen = 3;
args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
break;
case TYPE_INSTANCE:
oplen = 5 + longest_to_int (expr->elts[endpos - 2].longconst);
args = 1;
break;
case OP_OBJC_MSGCALL: /* Objective C message (method) call. */
oplen = 4;
args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
break;
case UNOP_MAX:
case UNOP_MIN:
oplen = 3;
break;
case UNOP_CAST_TYPE:
case UNOP_DYNAMIC_CAST:
case UNOP_REINTERPRET_CAST:
case UNOP_MEMVAL_TYPE:
oplen = 1;
args = 2;
break;
case BINOP_VAL:
case UNOP_CAST:
case UNOP_MEMVAL:
oplen = 3;
args = 1;
break;
case UNOP_ABS:
case UNOP_CAP:
case UNOP_CHR:
case UNOP_FLOAT:
case UNOP_HIGH:
case UNOP_ODD:
case UNOP_ORD:
case UNOP_TRUNC:
case OP_TYPEOF:
case OP_DECLTYPE:
case OP_TYPEID:
oplen = 1;
args = 1;
break;
case OP_ADL_FUNC:
oplen = longest_to_int (expr->elts[endpos - 2].longconst);
oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
oplen++;
oplen++;
break;
case STRUCTOP_STRUCT:
case STRUCTOP_PTR:
args = 1;
/* fall through */
case OP_REGISTER:
case OP_M2_STRING:
case OP_STRING:
case OP_OBJC_NSSTRING: /* Objective C Foundation Class
NSString constant. */
case OP_OBJC_SELECTOR: /* Objective C "@selector" pseudo-op. */
case OP_NAME:
oplen = longest_to_int (expr->elts[endpos - 2].longconst);
oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
break;
case OP_ARRAY:
oplen = 4;
args = longest_to_int (expr->elts[endpos - 2].longconst);
args -= longest_to_int (expr->elts[endpos - 3].longconst);
args += 1;
break;
case TERNOP_COND:
case TERNOP_SLICE:
args = 3;
break;
/* Modula-2 */
case MULTI_SUBSCRIPT:
oplen = 3;
args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
break;
case BINOP_ASSIGN_MODIFY:
oplen = 3;
args = 2;
break;
/* C++ */
case OP_THIS:
oplen = 2;
break;
case OP_RANGE:
oplen = 3;
range_flag = (enum range_flag)
longest_to_int (expr->elts[endpos - 2].longconst);
/* Assume the range has 2 arguments (low bound and high bound), then
reduce the argument count if any bounds are set to default. */
args = 2;
if (range_flag & RANGE_HAS_STRIDE)
++args;
if (range_flag & RANGE_LOW_BOUND_DEFAULT)
--args;
if (range_flag & RANGE_HIGH_BOUND_DEFAULT)
--args;
break;
default:
args = 1 + (i < (int) BINOP_END);
}
*oplenp = oplen;
*argsp = args;
}
/* Copy the subexpression ending just before index INEND in INEXPR
into OUTEXPR, starting at index OUTBEG.
In the process, convert it from suffix to prefix form.
If LAST_STRUCT is -1, then this function always returns -1.
Otherwise, it returns the index of the subexpression which is the
left-hand-side of the expression at LAST_STRUCT. */
static int
prefixify_subexp (struct expression *inexpr,
struct expression *outexpr, int inend, int outbeg,
int last_struct)
{
int oplen;
int args;
int i;
int *arglens;
int result = -1;
operator_length (inexpr, inend, &oplen, &args);
/* Copy the final operator itself, from the end of the input
to the beginning of the output. */
inend -= oplen;
memcpy (&outexpr->elts[outbeg], &inexpr->elts[inend],
EXP_ELEM_TO_BYTES (oplen));
outbeg += oplen;
if (last_struct == inend)
result = outbeg - oplen;
/* Find the lengths of the arg subexpressions. */
arglens = (int *) alloca (args * sizeof (int));
for (i = args - 1; i >= 0; i--)
{
oplen = length_of_subexp (inexpr, inend);
arglens[i] = oplen;
inend -= oplen;
}
/* Now copy each subexpression, preserving the order of
the subexpressions, but prefixifying each one.
In this loop, inend starts at the beginning of
the expression this level is working on
and marches forward over the arguments.
outbeg does similarly in the output. */
for (i = 0; i < args; i++)
{
int r;
oplen = arglens[i];
inend += oplen;
r = prefixify_subexp (inexpr, outexpr, inend, outbeg, last_struct);
if (r != -1)
{
/* Return immediately. We probably have only parsed a
partial expression, so we don't want to try to reverse
the other operands. */
return r;
}
outbeg += oplen;
}
return result;
}
/* Read an expression from the string *STRINGPTR points to,
parse it, and return a pointer to a struct expression that we malloc.
Use block BLOCK as the lexical context for variable names;
if BLOCK is zero, use the block of the selected stack frame.
Meanwhile, advance *STRINGPTR to point after the expression,
at the first nonwhite character that is not part of the expression
(possibly a null character).
If COMMA is nonzero, stop if a comma is reached. */
expression_up
parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
int comma, innermost_block_tracker *tracker)
{
return parse_exp_in_context (stringptr, pc, block, comma, false, NULL,
tracker, nullptr);
}
/* As for parse_exp_1, except that if VOID_CONTEXT_P, then
no value is expected from the expression.
OUT_SUBEXP is set when attempting to complete a field name; in this
case it is set to the index of the subexpression on the
left-hand-side of the struct op. If not doing such completion, it
is left untouched. */
static expression_up
parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
const struct block *block,
int comma, bool void_context_p, int *out_subexp,
innermost_block_tracker *tracker,
expr_completion_state *cstate)
{
const struct language_defn *lang = NULL;
if (*stringptr == 0 || **stringptr == 0)
error_no_arg (_("expression to compute"));
const struct block *expression_context_block = block;
CORE_ADDR expression_context_pc = 0;
innermost_block_tracker local_tracker;
if (tracker == nullptr)
tracker = &local_tracker;
/* If no context specified, try using the current frame, if any. */
if (!expression_context_block)
expression_context_block = get_selected_block (&expression_context_pc);
else if (pc == 0)
expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
else
expression_context_pc = pc;
/* Fall back to using the current source static context, if any. */
if (!expression_context_block)
{
struct symtab_and_line cursal = get_current_source_symtab_and_line ();
if (cursal.symtab)
expression_context_block
= BLOCKVECTOR_BLOCK (SYMTAB_BLOCKVECTOR (cursal.symtab),
STATIC_BLOCK);
if (expression_context_block)
expression_context_pc = BLOCK_ENTRY_PC (expression_context_block);
}
if (language_mode == language_mode_auto && block != NULL)
{
/* Find the language associated to the given context block.
Default to the current language if it can not be determined.
Note that using the language corresponding to the current frame
can sometimes give unexpected results. For instance, this
routine is often called several times during the inferior
startup phase to re-parse breakpoint expressions after
a new shared library has been loaded. The language associated
to the current frame at this moment is not relevant for
the breakpoint. Using it would therefore be silly, so it seems
better to rely on the current language rather than relying on
the current frame language to parse the expression. That's why
we do the following language detection only if the context block
has been specifically provided. */
struct symbol *func = block_linkage_function (block);
if (func != NULL)
lang = language_def (func->language ());
if (lang == NULL || lang->la_language == language_unknown)
lang = current_language;
}
else
lang = current_language;
/* get_current_arch may reset CURRENT_LANGUAGE via select_frame.
While we need CURRENT_LANGUAGE to be set to LANG (for lookup_symbol
and others called from *.y) ensure CURRENT_LANGUAGE gets restored
to the value matching SELECTED_FRAME as set by get_current_arch. */
parser_state ps (lang, get_current_arch (), expression_context_block,
expression_context_pc, comma, *stringptr,
cstate != nullptr, tracker, void_context_p);
scoped_restore_current_language lang_saver;
set_language (lang->la_language);
try
{
lang->parser (&ps);
}
catch (const gdb_exception &except)
{
/* If parsing for completion, allow this to succeed; but if no
expression elements have been written, then there's nothing
to do, so fail. */
if (! ps.parse_completion
|| (ps.expout->op == nullptr && ps.expout_ptr == 0))
throw;
}
/* We have to operate on an "expression *", due to la_post_parser,
which explains this funny-looking double release. */
expression_up result = ps.release ();
/* Convert expression from postfix form as generated by yacc
parser, to a prefix form. */
if (expressiondebug)
dump_raw_expression (result.get (), gdb_stdlog,
"before conversion to prefix form");
if (result->op == nullptr)
{
int subexp = prefixify_expression (result.get (),
ps.m_completion_state.expout_last_struct);
if (out_subexp)
*out_subexp = subexp;
lang->post_parser (&result, &ps);
}
else
result->op->set_outermost ();
if (expressiondebug)
dump_prefix_expression (result.get (), gdb_stdlog);
if (cstate != nullptr)
*cstate = std::move (ps.m_completion_state);
*stringptr = ps.lexptr;
return result;
}
/* Parse STRING as an expression, and complain if this fails to use up
all of the contents of STRING. TRACKER, if non-null, will be
updated by the parser. VOID_CONTEXT_P should be true to indicate
that the expression may be expected to return a value with void
type. Parsers are free to ignore this, or to use it to help with
overload resolution decisions. */
expression_up
parse_expression (const char *string, innermost_block_tracker *tracker,
bool void_context_p)
{
expression_up exp = parse_exp_in_context (&string, 0, nullptr, 0,
void_context_p, nullptr,
tracker, nullptr);
if (*string)
error (_("Junk after end of expression."));
return exp;
}
/* Same as parse_expression, but using the given language (LANG)
to parse the expression. */
expression_up
parse_expression_with_language (const char *string, enum language lang)
{
gdb::optional<scoped_restore_current_language> lang_saver;
if (current_language->la_language != lang)
{
lang_saver.emplace ();
set_language (lang);
}
return parse_expression (string);
}
/* Parse STRING as an expression. If parsing ends in the middle of a
field reference, return the type of the left-hand-side of the
reference; furthermore, if the parsing ends in the field name,
return the field name in *NAME. If the parsing ends in the middle
of a field reference, but the reference is somehow invalid, throw
an exception. In all other cases, return NULL. */
struct type *
parse_expression_for_completion (const char *string,
gdb::unique_xmalloc_ptr<char> *name,
enum type_code *code)
{
expression_up exp;
struct value *val;
int subexp;
expr_completion_state cstate;
try
{
exp = parse_exp_in_context (&string, 0, 0, 0, false, &subexp,
nullptr, &cstate);
}
catch (const gdb_exception_error &except)
{
/* Nothing, EXP remains NULL. */
}
if (exp == NULL)
return NULL;
if (cstate.expout_tag_completion_type != TYPE_CODE_UNDEF)
{
*code = cstate.expout_tag_completion_type;
*name = std::move (cstate.expout_completion_name);
return NULL;
}
if (cstate.expout_last_struct == -1)
return NULL;
const char *fieldname = extract_field_op (exp.get (), &subexp);
if (fieldname == NULL)
{
name->reset ();
return NULL;
}
name->reset (xstrdup (fieldname));
/* This might throw an exception. If so, we want to let it
propagate. */
val = evaluate_subexpression_type (exp.get (), subexp);
return value_type (val);
}
/* Parse floating point value P of length LEN.
Return false if invalid, true if valid.
The successfully parsed number is stored in DATA in
target format for floating-point type TYPE.
NOTE: This accepts the floating point syntax that sscanf accepts. */
bool
parse_float (const char *p, int len,
const struct type *type, gdb_byte *data)
{
return target_float_from_string (data, type, std::string (p, len));
}
/* This function avoids direct calls to fprintf
in the parser generated debug code. */
void
parser_fprintf (FILE *x, const char *y, ...)
{
va_list args;
va_start (args, y);
if (x == stderr)
vfprintf_unfiltered (gdb_stderr, y, args);
else
{
fprintf_unfiltered (gdb_stderr, " Unknown FILE used.\n");
vfprintf_unfiltered (gdb_stderr, y, args);
}
va_end (args);
}
/* Implementation of the exp_descriptor method operator_check. */
int
operator_check_standard (struct expression *exp, int pos,
int (*objfile_func) (struct objfile *objfile,
void *data),
void *data)
{
const union exp_element *const elts = exp->elts;
struct type *type = NULL;
struct objfile *objfile = NULL;
/* Extended operators should have been already handled by exp_descriptor
iterate method of its specific language. */
gdb_assert (elts[pos].opcode < OP_EXTENDED0);
/* Track the callers of write_exp_elt_type for this table. */
switch (elts[pos].opcode)
{
case BINOP_VAL:
case OP_COMPLEX:
case OP_FLOAT:
case OP_LONG:
case OP_SCOPE:
case OP_TYPE:
case UNOP_CAST:
case UNOP_MAX:
case UNOP_MEMVAL:
case UNOP_MIN:
type = elts[pos + 1].type;
break;
case TYPE_INSTANCE:
{
LONGEST arg, nargs = elts[pos + 2].longconst;
for (arg = 0; arg < nargs; arg++)
{
struct type *inst_type = elts[pos + 3 + arg].type;
struct objfile *inst_objfile = inst_type->objfile_owner ();
if (inst_objfile && (*objfile_func) (inst_objfile, data))
return 1;
}
}
break;
case OP_VAR_VALUE:
{
const struct block *const block = elts[pos + 1].block;
const struct symbol *const symbol = elts[pos + 2].symbol;
/* Check objfile where the variable itself is placed. */
if ((*objfile_func) (symbol_objfile (symbol), data))
return 1;
/* Check objfile where is placed the code touching the variable. */
objfile = block_objfile (block);
type = SYMBOL_TYPE (symbol);
}
break;
case OP_VAR_MSYM_VALUE:
objfile = elts[pos + 1].objfile;
break;
}
/* Invoke callbacks for TYPE and OBJFILE if they were set as non-NULL. */
if (type != nullptr && type->objfile_owner () != nullptr
&& objfile_func (type->objfile_owner (), data))
return 1;
if (objfile && (*objfile_func) (objfile, data))
return 1;
return 0;
}
/* Call OBJFILE_FUNC for any objfile found being referenced by EXP.
OBJFILE_FUNC is never called with NULL OBJFILE. OBJFILE_FUNC get
passed an arbitrary caller supplied DATA pointer. If OBJFILE_FUNC
returns non-zero value then (any other) non-zero value is immediately
returned to the caller. Otherwise zero is returned after iterating
through whole EXP. */
static int
exp_iterate (struct expression *exp,
int (*objfile_func) (struct objfile *objfile, void *data),
void *data)
{
int endpos;
for (endpos = exp->nelts; endpos > 0; )
{
int pos, args, oplen = 0;
operator_length (exp, endpos, &oplen, &args);
gdb_assert (oplen > 0);
pos = endpos - oplen;
if (exp->language_defn->expression_ops ()->operator_check (exp, pos,
objfile_func,
data))
return 1;
endpos = pos;
}
return 0;
}
/* Helper for exp_uses_objfile. */
static int
exp_uses_objfile_iter (struct objfile *exp_objfile, void *objfile_voidp)
{
struct objfile *objfile = (struct objfile *) objfile_voidp;
if (exp_objfile->separate_debug_objfile_backlink)
exp_objfile = exp_objfile->separate_debug_objfile_backlink;
return exp_objfile == objfile;
}
/* Return 1 if EXP uses OBJFILE (and will become dangling when OBJFILE
is unloaded), otherwise return 0. OBJFILE must not be a separate debug info
file. */
int
exp_uses_objfile (struct expression *exp, struct objfile *objfile)
{
gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
if (exp->op != nullptr)
return exp->op->uses_objfile (objfile);
return exp_iterate (exp, exp_uses_objfile_iter, objfile);
}
/* Reallocate the `expout' pointer inside PS so that it can accommodate
at least LENELT expression elements. This function does nothing if
there is enough room for the elements. */
static void
increase_expout_size (struct expr_builder *ps, size_t lenelt)
{
if ((ps->expout_ptr + lenelt) >= ps->expout_size)
{
ps->expout_size = std::max (ps->expout_size * 2,
ps->expout_ptr + lenelt + 10);
ps->expout->resize (ps->expout_size);
}
}
void _initialize_parse ();
void
_initialize_parse ()
{
add_setshow_zuinteger_cmd ("expression", class_maintenance,
&expressiondebug,
_("Set expression debugging."),
_("Show expression debugging."),
_("When non-zero, the internal representation "
"of expressions will be printed."),
NULL,
show_expressiondebug,
&setdebuglist, &showdebuglist);
add_setshow_boolean_cmd ("parser", class_maintenance,
&parser_debug,
_("Set parser debugging."),
_("Show parser debugging."),
_("When non-zero, expression parser "
"tracing will be enabled."),
NULL,
show_parserdebug,
&setdebuglist, &showdebuglist);
}
|