summaryrefslogtreecommitdiff
path: root/gdb/parse.c
blob: d4a6a0519376740ca624f3ef7d9a9b02e0d377d0 (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
/* Parse expressions for GDB.
   Copyright 1986, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   1998, 1999, 2000, 2001 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 2 of the License, or
   (at your option) any later version.

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

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

/* 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 <ctype.h>

#include "defs.h"
#include "gdb_string.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"		/* for NUM_PSEUDO_REGS.  NOTE: replace 
				   with "gdbarch.h" when appropriate.  */
#include "doublest.h"
#include "gdb_assert.h"
#include "block.h"


/* Symbols which architectures can redefine.  */

/* Some systems have routines whose names start with `$'.  Giving this
   macro a non-zero value tells GDB's expression parser to check for
   such routines when parsing tokens that begin with `$'.

   On HP-UX, certain system routines (millicode) have names beginning
   with `$' or `$$'.  For example, `$$dyncall' is a millicode routine
   that handles inter-space procedure calls on PA-RISC.  */
#ifndef SYMBOLS_CAN_START_WITH_DOLLAR
#define SYMBOLS_CAN_START_WITH_DOLLAR (0)
#endif



/* Global variables declared in parser-defs.h (and commented there).  */
struct expression *expout;
int expout_size;
int expout_ptr;
struct block *expression_context_block;
CORE_ADDR expression_context_pc;
struct block *innermost_block;
int arglist_len;
union type_stack_elt *type_stack;
int type_stack_depth, type_stack_size;
char *lexptr;
char *prev_lexptr;
char *namecopy;
int paren_depth;
int comma_terminates;

static int expressiondebug = 0;

extern int hp_som_som_object_present;

static void free_funcalls (void *ignore);

static void prefixify_expression (struct expression *);

static void prefixify_subexp (struct expression *, struct expression *, int,
			      int);

void _initialize_parse (void);

/* Data structure for saving values of arglist_len for function calls whose
   arguments contain other function calls.  */

struct funcall
  {
    struct funcall *next;
    int arglist_len;
  };

static struct funcall *funcall_chain;

/* Begin counting arguments for a function call,
   saving the data about any containing call.  */

void
start_arglist (void)
{
  register struct funcall *new;

  new = (struct funcall *) xmalloc (sizeof (struct funcall));
  new->next = funcall_chain;
  new->arglist_len = arglist_len;
  arglist_len = 0;
  funcall_chain = new;
}

/* Return the number of arguments in a function call just terminated,
   and restore the data for the containing function call.  */

int
end_arglist (void)
{
  register int val = arglist_len;
  register struct funcall *call = funcall_chain;
  funcall_chain = call->next;
  arglist_len = call->arglist_len;
  xfree (call);
  return val;
}

/* Free everything in the funcall chain.
   Used when there is an error inside parsing.  */

static void
free_funcalls (void *ignore)
{
  register struct funcall *call, *next;

  for (call = funcall_chain; call; call = next)
    {
      next = call->next;
      xfree (call);
    }
}

/* 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 */

void
write_exp_elt (union exp_element expelt)
{
  if (expout_ptr >= expout_size)
    {
      expout_size *= 2;
      expout = (struct expression *)
	xrealloc ((char *) expout, sizeof (struct expression)
		  + EXP_ELEM_TO_BYTES (expout_size));
    }
  expout->elts[expout_ptr++] = expelt;
}

void
write_exp_elt_opcode (enum exp_opcode expelt)
{
  union exp_element tmp;

  tmp.opcode = expelt;

  write_exp_elt (tmp);
}

void
write_exp_elt_sym (struct symbol *expelt)
{
  union exp_element tmp;

  tmp.symbol = expelt;

  write_exp_elt (tmp);
}

void
write_exp_elt_block (struct block *b)
{
  union exp_element tmp;
  tmp.block = b;
  write_exp_elt (tmp);
}

void
write_exp_elt_longcst (LONGEST expelt)
{
  union exp_element tmp;

  tmp.longconst = expelt;

  write_exp_elt (tmp);
}

void
write_exp_elt_dblcst (DOUBLEST expelt)
{
  union exp_element tmp;

  tmp.doubleconst = expelt;

  write_exp_elt (tmp);
}

void
write_exp_elt_type (struct type *expelt)
{
  union exp_element tmp;

  tmp.type = expelt;

  write_exp_elt (tmp);
}

void
write_exp_elt_intern (struct internalvar *expelt)
{
  union exp_element tmp;

  tmp.internalvar = expelt;

  write_exp_elt (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
   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 stoken str)
{
  register int len = str.length;
  register int lenelt;
  register 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);

  /* Ensure that we have enough available expression elements to store
     everything. */

  if ((expout_ptr + lenelt) >= expout_size)
    {
      expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);
      expout = (struct expression *)
	xrealloc ((char *) expout, (sizeof (struct expression)
				    + EXP_ELEM_TO_BYTES (expout_size)));
    }

  /* 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 ((LONGEST) len);
  strdata = (char *) &expout->elts[expout_ptr];
  memcpy (strdata, str.ptr, len);
  *(strdata + len) = '\0';
  expout_ptr += lenelt - 2;
  write_exp_elt_longcst ((LONGEST) len);
}

/* 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 stoken str)
{
  register int bits = str.length;	/* length in bits */
  register int len = (bits + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
  register int lenelt;
  register 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);

  /* Ensure that we have enough available expression elements to store
     everything. */

  if ((expout_ptr + lenelt) >= expout_size)
    {
      expout_size = max (expout_size * 2, expout_ptr + lenelt + 10);
      expout = (struct expression *)
	xrealloc ((char *) expout, (sizeof (struct expression)
				    + EXP_ELEM_TO_BYTES (expout_size)));
    }

  /* 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 ((LONGEST) bits);
  strdata = (char *) &expout->elts[expout_ptr];
  memcpy (strdata, str.ptr, len);
  expout_ptr += lenelt - 2;
  write_exp_elt_longcst ((LONGEST) bits);
}

/* Add the appropriate elements for a minimal symbol to the end of
   the expression.  The rationale behind passing in text_symbol_type and
   data_symbol_type was so that Modula-2 could pass in WORD for
   data_symbol_type.  Perhaps it still is useful to have those types vary
   based on the language, but they no longer have names like "int", so
   the initial rationale is gone.  */

static struct type *msym_text_symbol_type;
static struct type *msym_data_symbol_type;
static struct type *msym_unknown_symbol_type;

void
write_exp_msymbol (struct minimal_symbol *msymbol, 
		   struct type *text_symbol_type, 
		   struct type *data_symbol_type)
{
  CORE_ADDR addr;

  write_exp_elt_opcode (OP_LONG);
  /* Let's make the type big enough to hold a 64-bit address.  */
  write_exp_elt_type (builtin_type_CORE_ADDR);

  addr = SYMBOL_VALUE_ADDRESS (msymbol);
  if (overlay_debugging)
    addr = symbol_overlayed_address (addr, SYMBOL_BFD_SECTION (msymbol));
  write_exp_elt_longcst ((LONGEST) addr);

  write_exp_elt_opcode (OP_LONG);

  write_exp_elt_opcode (UNOP_MEMVAL);
  switch (msymbol->type)
    {
    case mst_text:
    case mst_file_text:
    case mst_solib_trampoline:
      write_exp_elt_type (msym_text_symbol_type);
      break;

    case mst_data:
    case mst_file_data:
    case mst_bss:
    case mst_file_bss:
      write_exp_elt_type (msym_data_symbol_type);
      break;

    default:
      write_exp_elt_type (msym_unknown_symbol_type);
      break;
    }
  write_exp_elt_opcode (UNOP_MEMVAL);
}

/* 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 stoken str)
{
  /* 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 = frame_map_name_to_regnum (str.ptr + 1, str.length - 1);
  if (i >= 0)
    goto handle_register;

  if (SYMBOLS_CAN_START_WITH_DOLLAR)
    {
      struct symbol *sym = NULL;
      struct minimal_symbol *msym = NULL;

      /* On HP-UX, certain system routines (millicode) have names beginning
	 with $ or $$, e.g. $$dyncall, which handles inter-space procedure
	 calls on PA-RISC. Check for those, first. */

      /* This code is not enabled on non HP-UX systems, since worst case 
	 symbol table lookup performance is awful, to put it mildly. */

      sym = lookup_symbol (copy_name (str), (struct block *) NULL,
			   VAR_NAMESPACE, (int *) NULL, (struct symtab **) NULL);
      if (sym)
	{
	  write_exp_elt_opcode (OP_VAR_VALUE);
	  write_exp_elt_block (block_found);	/* set by lookup_symbol */
	  write_exp_elt_sym (sym);
	  write_exp_elt_opcode (OP_VAR_VALUE);
	  return;
	}
      msym = lookup_minimal_symbol (copy_name (str), NULL, NULL);
      if (msym)
	{
	  write_exp_msymbol (msym,
			     lookup_function_type (builtin_type_int),
			     builtin_type_int);
	  return;
	}
    }

  /* Any other names starting in $ are debugger internal variables.  */

  write_exp_elt_opcode (OP_INTERNALVAR);
  write_exp_elt_intern (lookup_internalvar (copy_name (str) + 1));
  write_exp_elt_opcode (OP_INTERNALVAR);
  return;
handle_last:
  write_exp_elt_opcode (OP_LAST);
  write_exp_elt_longcst ((LONGEST) i);
  write_exp_elt_opcode (OP_LAST);
  return;
handle_register:
  write_exp_elt_opcode (OP_REGISTER);
  write_exp_elt_longcst (i);
  write_exp_elt_opcode (OP_REGISTER);
  return;
}


/* Parse a string that is possibly a namespace / nested class
   specification, i.e., something of the form A::B::C::x.  Input
   (NAME) is the entire string; LEN is the current valid length; the
   output is a string, TOKEN, which points to the largest recognized
   prefix which is a series of namespaces or classes.  CLASS_PREFIX is
   another output, which records whether a nested class spec was
   recognized (= 1) or a fully qualified variable name was found (=
   0).  ARGPTR is side-effected (if non-NULL) to point to beyond the
   string recognized and consumed by this routine.

   The return value is a pointer to the symbol for the base class or
   variable if found, or NULL if not found.  Callers must check this
   first -- if NULL, the outputs may not be correct. 

   This function is used c-exp.y.  This is used specifically to get
   around HP aCC (and possibly other compilers), which insists on
   generating names with embedded colons for namespace or nested class
   members.

   (Argument LEN is currently unused. 1997-08-27)

   Callers must free memory allocated for the output string TOKEN.  */

static const char coloncolon[2] =
{':', ':'};

struct symbol *
parse_nested_classes_for_hpacc (char *name, int len, char **token,
				int *class_prefix, char **argptr)
{
  /* Comment below comes from decode_line_1 which has very similar
     code, which is called for "break" command parsing. */

  /* We have what looks like a class or namespace
     scope specification (A::B), possibly with many
     levels of namespaces or classes (A::B::C::D).

     Some versions of the HP ANSI C++ compiler (as also possibly
     other compilers) generate class/function/member names with
     embedded double-colons if they are inside namespaces. To
     handle this, we loop a few times, considering larger and
     larger prefixes of the string as though they were single
     symbols.  So, if the initially supplied string is
     A::B::C::D::foo, we have to look up "A", then "A::B",
     then "A::B::C", then "A::B::C::D", and finally
     "A::B::C::D::foo" as single, monolithic symbols, because
     A, B, C or D may be namespaces.

     Note that namespaces can nest only inside other
     namespaces, and not inside classes.  So we need only
     consider *prefixes* of the string; there is no need to look up
     "B::C" separately as a symbol in the previous example. */

  register char *p;
  char *start, *end;
  char *prefix = NULL;
  char *tmp;
  struct symbol *sym_class = NULL;
  struct symbol *sym_var = NULL;
  struct type *t;
  int prefix_len = 0;
  int done = 0;
  char *q;

  /* Check for HP-compiled executable -- in other cases
     return NULL, and caller must default to standard GDB
     behaviour. */

  if (!hp_som_som_object_present)
    return (struct symbol *) NULL;

  p = name;

  /* Skip over whitespace and possible global "::" */
  while (*p && (*p == ' ' || *p == '\t'))
    p++;
  if (p[0] == ':' && p[1] == ':')
    p += 2;
  while (*p && (*p == ' ' || *p == '\t'))
    p++;

  while (1)
    {
      /* Get to the end of the next namespace or class spec. */
      /* If we're looking at some non-token, fail immediately */
      start = p;
      if (!(isalpha (*p) || *p == '$' || *p == '_'))
	return (struct symbol *) NULL;
      p++;
      while (*p && (isalnum (*p) || *p == '$' || *p == '_'))
	p++;

      if (*p == '<')
	{
	  /* If we have the start of a template specification,
	     scan right ahead to its end */
	  q = find_template_name_end (p);
	  if (q)
	    p = q;
	}

      end = p;

      /* Skip over "::" and whitespace for next time around */
      while (*p && (*p == ' ' || *p == '\t'))
	p++;
      if (p[0] == ':' && p[1] == ':')
	p += 2;
      while (*p && (*p == ' ' || *p == '\t'))
	p++;

      /* Done with tokens? */
      if (!*p || !(isalpha (*p) || *p == '$' || *p == '_'))
	done = 1;

      tmp = (char *) alloca (prefix_len + end - start + 3);
      if (prefix)
	{
	  memcpy (tmp, prefix, prefix_len);
	  memcpy (tmp + prefix_len, coloncolon, 2);
	  memcpy (tmp + prefix_len + 2, start, end - start);
	  tmp[prefix_len + 2 + end - start] = '\000';
	}
      else
	{
	  memcpy (tmp, start, end - start);
	  tmp[end - start] = '\000';
	}

      prefix = tmp;
      prefix_len = strlen (prefix);

      /* See if the prefix we have now is something we know about */

      if (!done)
	{
	  /* More tokens to process, so this must be a class/namespace */
	  sym_class = lookup_symbol (prefix, 0, STRUCT_NAMESPACE,
				     0, (struct symtab **) NULL);
	}
      else
	{
	  /* No more tokens, so try as a variable first */
	  sym_var = lookup_symbol (prefix, 0, VAR_NAMESPACE,
				   0, (struct symtab **) NULL);
	  /* If failed, try as class/namespace */
	  if (!sym_var)
	    sym_class = lookup_symbol (prefix, 0, STRUCT_NAMESPACE,
				       0, (struct symtab **) NULL);
	}

      if (sym_var ||
	  (sym_class &&
	   (t = check_typedef (SYMBOL_TYPE (sym_class)),
	    (TYPE_CODE (t) == TYPE_CODE_STRUCT
	     || TYPE_CODE (t) == TYPE_CODE_UNION))))
	{
	  /* We found a valid token */
	  *token = (char *) xmalloc (prefix_len + 1);
	  memcpy (*token, prefix, prefix_len);
	  (*token)[prefix_len] = '\000';
	  break;
	}

      /* No variable or class/namespace found, no more tokens */
      if (done)
	return (struct symbol *) NULL;
    }

  /* Out of loop, so we must have found a valid token */
  if (sym_var)
    *class_prefix = 0;
  else
    *class_prefix = 1;

  if (argptr)
    *argptr = done ? p : end;

  return sym_var ? sym_var : sym_class;		/* found */
}

char *
find_template_name_end (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.  */

char *
copy_name (struct stoken token)
{
  memcpy (namecopy, token.ptr, token.length);
  namecopy[token.length] = 0;
  return namecopy;
}

/* Reverse an expression from suffix form (in which it is constructed)
   to prefix form (in which we can conveniently print or execute it).  */

static void
prefixify_expression (register struct expression *expr)
{
  register int len =
  sizeof (struct expression) + EXP_ELEM_TO_BYTES (expr->nelts);
  register struct expression *temp;
  register int inpos = expr->nelts, outpos = 0;

  temp = (struct expression *) alloca (len);

  /* Copy the original expression into temp.  */
  memcpy (temp, expr, len);

  prefixify_subexp (temp, expr, inpos, outpos);
}

/* Return the number of exp_elements in the subexpression of EXPR
   whose last exp_element is at index ENDPOS - 1 in EXPR.  */

int
length_of_subexp (register struct expression *expr, register int endpos)
{
  register int oplen = 1;
  register int args = 0;
  register int i;

  if (endpos < 1)
    error ("?error in length_of_subexp");

  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_DOUBLE:
    case OP_VAR_VALUE:
      oplen = 4;
      break;

    case OP_TYPE:
    case OP_BOOL:
    case OP_LAST:
    case OP_REGISTER:
    case OP_INTERNALVAR:
      oplen = 3;
      break;

    case OP_COMPLEX:
      oplen = 1;
      args = 2;
      break;

    case OP_FUNCALL:
    case OP_F77_UNDETERMINED_ARGLIST:
      oplen = 3;
      args = 1 + longest_to_int (expr->elts[endpos - 2].longconst);
      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 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:
      oplen = 1;
      args = 1;
      break;

    case OP_LABELED:
    case STRUCTOP_STRUCT:
    case STRUCTOP_PTR:
      args = 1;
      /* fall through */
    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:
    case OP_EXPRSTRING:
      oplen = longest_to_int (expr->elts[endpos - 2].longconst);
      oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
      break;

    case OP_BITSTRING:
      oplen = longest_to_int (expr->elts[endpos - 2].longconst);
      oplen = (oplen + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
      oplen = 4 + BYTES_TO_EXP_ELEM (oplen);
      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:
    case TERNOP_SLICE_COUNT:
      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:
    case OP_OBJC_SELF:
      oplen = 2;
      break;

    default:
      args = 1 + (i < (int) BINOP_END);
    }

  while (args > 0)
    {
      oplen += length_of_subexp (expr, endpos - oplen);
      args--;
    }

  return oplen;
}

/* 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.  */

static void
prefixify_subexp (register struct expression *inexpr,
		  struct expression *outexpr, register int inend, int outbeg)
{
  register int oplen = 1;
  register int args = 0;
  register int i;
  int *arglens;
  enum exp_opcode opcode;

  /* Compute how long the last operation is (in OPLEN),
     and also how many preceding subexpressions serve as
     arguments for it (in ARGS).  */

  opcode = inexpr->elts[inend - 1].opcode;
  switch (opcode)
    {
      /* C++  */
    case OP_SCOPE:
      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
      oplen = 5 + BYTES_TO_EXP_ELEM (oplen + 1);
      break;

    case OP_LONG:
    case OP_DOUBLE:
    case OP_VAR_VALUE:
      oplen = 4;
      break;

    case OP_TYPE:
    case OP_BOOL:
    case OP_LAST:
    case OP_REGISTER:
    case OP_INTERNALVAR:
      oplen = 3;
      break;

    case OP_COMPLEX:
      oplen = 1;
      args = 2;
      break;

    case OP_FUNCALL:
    case OP_F77_UNDETERMINED_ARGLIST:
      oplen = 3;
      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
      break;

    case OP_OBJC_MSGCALL:	/* Objective C message (method) call */
      oplen = 4;
      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
      break;

    case UNOP_MIN:
    case UNOP_MAX:
      oplen = 3;
      break;

    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:
      oplen = 1;
      args = 1;
      break;

    case STRUCTOP_STRUCT:
    case STRUCTOP_PTR:
    case OP_LABELED:
      args = 1;
      /* fall through */
    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:
    case OP_EXPRSTRING:
      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
      oplen = 4 + BYTES_TO_EXP_ELEM (oplen + 1);
      break;

    case OP_BITSTRING:
      oplen = longest_to_int (inexpr->elts[inend - 2].longconst);
      oplen = (oplen + HOST_CHAR_BIT - 1) / HOST_CHAR_BIT;
      oplen = 4 + BYTES_TO_EXP_ELEM (oplen);
      break;

    case OP_ARRAY:
      oplen = 4;
      args = longest_to_int (inexpr->elts[inend - 2].longconst);
      args -= longest_to_int (inexpr->elts[inend - 3].longconst);
      args += 1;
      break;

    case TERNOP_COND:
    case TERNOP_SLICE:
    case TERNOP_SLICE_COUNT:
      args = 3;
      break;

    case BINOP_ASSIGN_MODIFY:
      oplen = 3;
      args = 2;
      break;

      /* Modula-2 */
    case MULTI_SUBSCRIPT:
      oplen = 3;
      args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst);
      break;

      /* C++ */
    case OP_THIS:
    case OP_OBJC_SELF:
      oplen = 2;
      break;

    default:
      args = 1 + ((int) opcode < (int) BINOP_END);
    }

  /* 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;

  /* 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++)
    {
      oplen = arglens[i];
      inend += oplen;
      prefixify_subexp (inexpr, outexpr, inend, outbeg);
      outbeg += oplen;
    }
}

/* This page contains the two entry points to this file.  */

/* 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.  */

struct expression *
parse_exp_1 (char **stringptr, struct block *block, int comma)
{
  struct cleanup *old_chain;

  lexptr = *stringptr;
  prev_lexptr = NULL;

  paren_depth = 0;
  type_stack_depth = 0;

  comma_terminates = comma;

  if (lexptr == 0 || *lexptr == 0)
    error_no_arg ("expression to compute");

  old_chain = make_cleanup (free_funcalls, 0 /*ignore*/);
  funcall_chain = 0;

  if (block)
    {
      expression_context_block = block;
      expression_context_pc = BLOCK_START (block);
    }
  else
    expression_context_block = get_selected_block (&expression_context_pc);

  namecopy = (char *) alloca (strlen (lexptr) + 1);
  expout_size = 10;
  expout_ptr = 0;
  expout = (struct expression *)
    xmalloc (sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_size));
  expout->language_defn = current_language;
  make_cleanup (free_current_contents, &expout);

  if (current_language->la_parser ())
    current_language->la_error (NULL);

  discard_cleanups (old_chain);

  /* 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 = (struct expression *)
    xrealloc ((char *) expout,
	      sizeof (struct expression) + EXP_ELEM_TO_BYTES (expout_ptr));;

  /* Convert expression from postfix form as generated by yacc
     parser, to a prefix form. */

  if (expressiondebug)
    dump_prefix_expression (expout, gdb_stdlog,
			    "before conversion to prefix form");

  prefixify_expression (expout);

  if (expressiondebug)
    dump_postfix_expression (expout, gdb_stdlog,
			     "after conversion to prefix form");

  *stringptr = lexptr;
  return expout;
}

/* Parse STRING as an expression, and complain if this fails
   to use up all of the contents of STRING.  */

struct expression *
parse_expression (char *string)
{
  register struct expression *exp;
  exp = parse_exp_1 (&string, 0, 0);
  if (*string)
    error ("Junk after end of expression.");
  return exp;
}

/* Stuff for maintaining a stack of types.  Currently just used by C, but
   probably useful for any language which declares its types "backwards".  */

static void
check_type_stack_depth (void)
{
  if (type_stack_depth == type_stack_size)
    {
      type_stack_size *= 2;
      type_stack = (union type_stack_elt *)
	xrealloc ((char *) type_stack, type_stack_size * sizeof (*type_stack));
    }
}

void
push_type (enum type_pieces tp)
{
  check_type_stack_depth ();
  type_stack[type_stack_depth++].piece = tp;
}

void
push_type_int (int n)
{
  check_type_stack_depth ();
  type_stack[type_stack_depth++].int_val = n;
}

void
push_type_address_space (char *string)
{
  push_type_int (address_space_name_to_int (string));
}

enum type_pieces
pop_type (void)
{
  if (type_stack_depth)
    return type_stack[--type_stack_depth].piece;
  return tp_end;
}

int
pop_type_int (void)
{
  if (type_stack_depth)
    return type_stack[--type_stack_depth].int_val;
  /* "Can't happen".  */
  return 0;
}

/* Pop the type stack and return the type which corresponds to FOLLOW_TYPE
   as modified by all the stuff on the stack.  */
struct type *
follow_types (struct type *follow_type)
{
  int done = 0;
  int make_const = 0;
  int make_volatile = 0;
  int make_addr_space = 0;
  int array_size;
  struct type *range_type;

  while (!done)
    switch (pop_type ())
      {
      case tp_end:
	done = 1;
	if (make_const)
	  follow_type = make_cv_type (make_const, 
				      TYPE_VOLATILE (follow_type), 
				      follow_type, 0);
	if (make_volatile)
	  follow_type = make_cv_type (TYPE_CONST (follow_type), 
				      make_volatile, 
				      follow_type, 0);
	if (make_addr_space)
	  follow_type = make_type_with_address_space (follow_type, 
						      make_addr_space);
	make_const = make_volatile = 0;
	make_addr_space = 0;
	break;
      case tp_const:
	make_const = 1;
	break;
      case tp_volatile:
	make_volatile = 1;
	break;
      case tp_space_identifier:
	make_addr_space = pop_type_int ();
	break;
      case tp_pointer:
	follow_type = lookup_pointer_type (follow_type);
	if (make_const)
	  follow_type = make_cv_type (make_const, 
				      TYPE_VOLATILE (follow_type), 
				      follow_type, 0);
	if (make_volatile)
	  follow_type = make_cv_type (TYPE_CONST (follow_type), 
				      make_volatile, 
				      follow_type, 0);
	if (make_addr_space)
	  follow_type = make_type_with_address_space (follow_type, 
						      make_addr_space);
	make_const = make_volatile = 0;
	make_addr_space = 0;
	break;
      case tp_reference:
	follow_type = lookup_reference_type (follow_type);
	if (make_const)
	  follow_type = make_cv_type (make_const, 
				      TYPE_VOLATILE (follow_type), 
				      follow_type, 0);
	if (make_volatile)
	  follow_type = make_cv_type (TYPE_CONST (follow_type), 
				      make_volatile, 
				      follow_type, 0);
	if (make_addr_space)
	  follow_type = make_type_with_address_space (follow_type, 
						      make_addr_space);
	make_const = make_volatile = 0;
	make_addr_space = 0;
	break;
      case tp_array:
	array_size = pop_type_int ();
	/* FIXME-type-allocation: need a way to free this type when we are
	   done with it.  */
	range_type =
	  create_range_type ((struct type *) NULL,
			     builtin_type_int, 0,
			     array_size >= 0 ? array_size - 1 : 0);
	follow_type =
	  create_array_type ((struct type *) NULL,
			     follow_type, range_type);
	if (array_size < 0)
	  TYPE_ARRAY_UPPER_BOUND_TYPE (follow_type)
	    = BOUND_CANNOT_BE_DETERMINED;
	break;
      case tp_function:
	/* FIXME-type-allocation: need a way to free this type when we are
	   done with it.  */
	follow_type = lookup_function_type (follow_type);
	break;
      }
  return follow_type;
}

static void build_parse (void);
static void
build_parse (void)
{
  int i;

  msym_text_symbol_type =
    init_type (TYPE_CODE_FUNC, 1, 0, "<text variable, no debug info>", NULL);
  TYPE_TARGET_TYPE (msym_text_symbol_type) = builtin_type_int;
  msym_data_symbol_type =
    init_type (TYPE_CODE_INT, TARGET_INT_BIT / HOST_CHAR_BIT, 0,
	       "<data variable, no debug info>", NULL);
  msym_unknown_symbol_type =
    init_type (TYPE_CODE_INT, 1, 0,
	       "<variable (not text or data), no debug info>",
	       NULL);
}

/* 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);
}

void
_initialize_parse (void)
{
  type_stack_size = 80;
  type_stack_depth = 0;
  type_stack = (union type_stack_elt *)
    xmalloc (type_stack_size * sizeof (*type_stack));

  build_parse ();

  /* FIXME - For the moment, handle types by swapping them in and out.
     Should be using the per-architecture data-pointer and a large
     struct. */
  register_gdbarch_swap (&msym_text_symbol_type, sizeof (msym_text_symbol_type), NULL);
  register_gdbarch_swap (&msym_data_symbol_type, sizeof (msym_data_symbol_type), NULL);
  register_gdbarch_swap (&msym_unknown_symbol_type, sizeof (msym_unknown_symbol_type), NULL);

  register_gdbarch_swap (NULL, 0, build_parse);

  add_show_from_set (
	    add_set_cmd ("expression", class_maintenance, var_zinteger,
			 (char *) &expressiondebug,
			 "Set expression debugging.\n\
When non-zero, the internal representation of expressions will be printed.",
			 &setdebuglist),
		      &showdebuglist);
}