summaryrefslogtreecommitdiff
path: root/lisp/gud.el
blob: 124a41bee82a727618a6ff8a36cd57a5f3277958 (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
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
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
;;; gud.el --- Grand Unified Debugger mode for gdb, sdb, dbx, or xdb under Emacs

;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
;; Maintainer: FSF
;; Keywords: unix, tools

;; Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.

;; This file is part of GNU Emacs.

;; GNU Emacs 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, or (at your option)
;; any later version.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; The ancestral gdb.el was by W. Schelter <wfs@rascal.ics.utexas.edu>
;; It was later rewritten by rms.  Some ideas were due to Masanobu. 
;; Grand Unification (sdb/dbx support) by Eric S. Raymond <esr@thyrsus.com>
;; The overloading code was then rewritten by Barry Warsaw <bwarsaw@cen.com>,
;; who also hacked the mode to use comint.el.  Shane Hartman <shane@spr.com>
;; added support for xdb (HPUX debugger).  Rick Sladkey <jrs@world.std.com>
;; wrote the GDB command completion code.  Dave Love <d.love@dl.ac.uk>
;; added the IRIX kluge, re-implemented the Mips-ish variant and added
;; a menu. Brian D. Carlstrom <bdc@ai.mit.edu> combined the IRIX kluge with 
;; the gud-xdb-directories hack producing gud-dbx-directories.

;;; Code:

(require 'comint)
(require 'etags)

;; ======================================================================
;; GUD commands must be visible in C buffers visited by GUD

(defvar gud-key-prefix "\C-x\C-a"
  "Prefix of all GUD commands valid in C buffers.")

(global-set-key (concat gud-key-prefix "\C-l") 'gud-refresh)
(define-key ctl-x-map " " 'gud-break)	;; backward compatibility hack

(defvar gud-marker-filter nil)
(put 'gud-marker-filter 'permanent-local t)
(defvar gud-find-file nil)
(put 'gud-find-file 'permanent-local t)

(defun gud-marker-filter (&rest args)
  (apply gud-marker-filter args))

(defun gud-find-file (file)
  ;; Don't get confused by double slashes in the name that comes from GDB.
  (while (string-match "//+" file)
    (setq file (replace-match "/" t t file)))
  (funcall gud-find-file file))

;; Keymap definitions for menu bar entries common to all debuggers and
;; slots for debugger-dependent ones in sensible places.  (Defined here
;; before use.)
(defvar gud-menu-map (make-sparse-keymap "Gud") nil)
(define-key gud-menu-map [refresh] '("Refresh" . gud-refresh))
(define-key gud-menu-map [remove] '("Remove Breakpoint" . gud-remove))
(define-key gud-menu-map [tbreak] nil)	; gdb, sdb and xdb
(define-key gud-menu-map [break] '("Set Breakpoint" . gud-break))
(define-key gud-menu-map [up] nil)	; gdb, dbx, and xdb
(define-key gud-menu-map [down] nil)	; gdb, dbx, and xdb
(define-key gud-menu-map [print] '("Print Expression" . gud-print))
(define-key gud-menu-map [finish] nil)	; gdb or xdb
(define-key gud-menu-map [stepi] '("Step Instruction" . gud-stepi))
(define-key gud-menu-map [step] '("Step Line" . gud-step))
(define-key gud-menu-map [next] '("Next Line" . gud-next))
(define-key gud-menu-map [cont] '("Continue" . gud-cont))

;; ======================================================================
;; command definition

;; This macro is used below to define some basic debugger interface commands.
;; Of course you may use `gud-def' with any other debugger command, including
;; user defined ones.

;; A macro call like (gud-def FUNC NAME KEY DOC) expands to a form
;; which defines FUNC to send the command NAME to the debugger, gives
;; it the docstring DOC, and binds that function to KEY in the GUD
;; major mode.  The function is also bound in the global keymap with the
;; GUD prefix.

(defmacro gud-def (func cmd key &optional doc)
  "Define FUNC to be a command sending STR and bound to KEY, with
optional doc string DOC.  Certain %-escapes in the string arguments
are interpreted specially if present.  These are:

  %f	name (without directory) of current source file. 
  %d	directory of current source file. 
  %l	number of current source line
  %e	text of the C lvalue or function-call expression surrounding point.
  %a	text of the hexadecimal address surrounding point
  %p	prefix argument to the command (if any) as a number

  The `current' source file is the file of the current buffer (if
we're in a C file) or the source file current at the last break or
step (if we're in the GUD buffer).
  The `current' line is that of the current buffer (if we're in a
source file) or the source line number at the last break or step (if
we're in the GUD buffer)."
  (list 'progn
	(list 'defun func '(arg)
	      (or doc "")
	      '(interactive "p")
	      (list 'gud-call cmd 'arg))
	(if key
	    (list 'define-key
		  '(current-local-map)
		  (concat "\C-c" key)
		  (list 'quote func)))
	(if key
	    (list 'global-set-key
		  (list 'concat 'gud-key-prefix key)
		  (list 'quote func)))))

;; Where gud-display-frame should put the debugging arrow.  This is
;; set by the marker-filter, which scans the debugger's output for
;; indications of the current program counter.
(defvar gud-last-frame nil)

;; Used by gud-refresh, which should cause gud-display-frame to redisplay
;; the last frame, even if it's been called before and gud-last-frame has
;; been set to nil.
(defvar gud-last-last-frame nil)

;; All debugger-specific information is collected here.
;; Here's how it works, in case you ever need to add a debugger to the mode.
;;
;; Each entry must define the following at startup:
;;
;;<name>
;; comint-prompt-regexp
;; gud-<name>-massage-args
;; gud-<name>-marker-filter
;; gud-<name>-find-file
;;
;; The job of the massage-args method is to modify the given list of
;; debugger arguments before running the debugger.
;;
;; The job of the marker-filter method is to detect file/line markers in
;; strings and set the global gud-last-frame to indicate what display
;; action (if any) should be triggered by the marker.  Note that only
;; whatever the method *returns* is displayed in the buffer; thus, you
;; can filter the debugger's output, interpreting some and passing on
;; the rest.
;;
;; The job of the find-file method is to visit and return the buffer indicated
;; by the car of gud-tag-frame.  This may be a file name, a tag name, or
;; something else.  It would be good if it also copied the Gud menubar entry.

;; ======================================================================
;; gdb functions

;;; History of argument lists passed to gdb.
(defvar gud-gdb-history nil)

(defun gud-gdb-massage-args (file args)
  (cons "-fullname" args))

(defvar gud-gdb-marker-regexp
  (concat "\032\032\\([^" path-separator "\n]*\\)" path-separator
	  "\\([0-9]*\\)" path-separator ".*\n"))

;; There's no guarantee that Emacs will hand the filter the entire
;; marker at once; it could be broken up across several strings.  We
;; might even receive a big chunk with several markers in it.  If we
;; receive a chunk of text which looks like it might contain the
;; beginning of a marker, we save it here between calls to the
;; filter.
(defvar gud-marker-acc "")
(make-variable-buffer-local 'gud-marker-acc)

(defun gud-gdb-marker-filter (string)
  (setq gud-marker-acc (concat gud-marker-acc string))
  (let ((output ""))

    ;; Process all the complete markers in this chunk.
    (while (string-match gud-gdb-marker-regexp gud-marker-acc)
      (setq

       ;; Extract the frame position from the marker.
       gud-last-frame
       (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
	     (string-to-int (substring gud-marker-acc
				       (match-beginning 2)
				       (match-end 2))))

       ;; Append any text before the marker to the output we're going
       ;; to return - we don't include the marker in this text.
       output (concat output
		      (substring gud-marker-acc 0 (match-beginning 0)))

       ;; Set the accumulator to the remaining text.
       gud-marker-acc (substring gud-marker-acc (match-end 0))))

    ;; Does the remaining text look like it might end with the
    ;; beginning of another marker?  If it does, then keep it in
    ;; gud-marker-acc until we receive the rest of it.  Since we
    ;; know the full marker regexp above failed, it's pretty simple to
    ;; test for marker starts.
    (if (string-match "\032.*\\'" gud-marker-acc)
	(progn
	  ;; Everything before the potential marker start can be output.
	  (setq output (concat output (substring gud-marker-acc
						 0 (match-beginning 0))))

	  ;; Everything after, we save, to combine with later input.
	  (setq gud-marker-acc
		(substring gud-marker-acc (match-beginning 0))))

      (setq output (concat output gud-marker-acc)
	    gud-marker-acc ""))

    output))

(defun gud-new-keymap (map)
  "Return a new keymap which inherits from MAP and has name `Gud'."
  (nconc (make-sparse-keymap "Gud") map))

(defun gud-make-debug-menu ()
  "Make sure the current local map has a [menu-bar debug] submap.
If it doesn't, replace it with a new map that inherits it,
and create such a submap in that new map."
  (if (and (current-local-map)
	   (lookup-key (current-local-map) [menu-bar debug]))
      nil
    (use-local-map (gud-new-keymap (current-local-map)))
    (define-key (current-local-map) [menu-bar debug]
      (cons "Gud" (gud-new-keymap gud-menu-map)))))

(defun gud-gdb-find-file (f)
  (save-excursion
    (let ((buf (find-file-noselect f)))
      (set-buffer buf)
      (gud-make-debug-menu)
      (local-set-key [menu-bar debug tbreak]
		     '("Temporary Breakpoint" . gud-tbreak))
      (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
      (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
      (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
      buf)))

(defvar gdb-minibuffer-local-map nil
  "Keymap for minibuffer prompting of gdb startup command.")
(if gdb-minibuffer-local-map
    ()
  (setq gdb-minibuffer-local-map (copy-keymap minibuffer-local-map))
  (define-key
    gdb-minibuffer-local-map "\C-i" 'comint-dynamic-complete-filename))

;;;###autoload
(defun gdb (command-line)
  "Run gdb on program FILE in buffer *gud-FILE*.
The directory containing FILE becomes the initial working directory
and source-file directory for your debugger."
  (interactive
   (list (read-from-minibuffer "Run gdb (like this): "
			       (if (consp gud-gdb-history)
				   (car gud-gdb-history)
				 "gdb ")
			       gdb-minibuffer-local-map nil
			       '(gud-gdb-history . 1))))

  (gud-common-init command-line 'gud-gdb-massage-args
		   'gud-gdb-marker-filter 'gud-gdb-find-file)

  (gud-def gud-break  "break %f:%l"  "\C-b" "Set breakpoint at current line.")
  (gud-def gud-tbreak "tbreak %f:%l" "\C-t" "Set temporary breakpoint at current line.")
  (gud-def gud-remove "clear %f:%l"  "\C-d" "Remove breakpoint at current line")
  (gud-def gud-step   "step %p"      "\C-s" "Step one source line with display.")
  (gud-def gud-stepi  "stepi %p"     "\C-i" "Step one instruction with display.")
  (gud-def gud-next   "next %p"      "\C-n" "Step one line (skip functions).")
  (gud-def gud-cont   "cont"         "\C-r" "Continue with display.")
  (gud-def gud-finish "finish"       "\C-f" "Finish executing current function.")
  (gud-def gud-up     "up %p"        "<" "Up N stack frames (numeric arg).")
  (gud-def gud-down   "down %p"      ">" "Down N stack frames (numeric arg).")
  (gud-def gud-print  "print %e"     "\C-p" "Evaluate C expression at point.")

  (local-set-key "\C-i" 'gud-gdb-complete-command)
  (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
  (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
  (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
  (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
  (setq comint-prompt-regexp "^(.*gdb[+]?) *")
  (setq paragraph-start comint-prompt-regexp)
  (run-hooks 'gdb-mode-hook)
  )

;; One of the nice features of GDB is its impressive support for
;; context-sensitive command completion.  We preserve that feature
;; in the GUD buffer by using a GDB command designed just for Emacs.

;; The completion process filter indicates when it is finished.
(defvar gud-gdb-complete-in-progress)

;; Since output may arrive in fragments we accumulate partials strings here.
(defvar gud-gdb-complete-string)

;; We need to know how much of the completion to chop off.
(defvar gud-gdb-complete-break)

;; The completion list is constructed by the process filter.
(defvar gud-gdb-complete-list)

(defvar gud-comint-buffer nil)

(defun gud-gdb-complete-command ()
  "Perform completion on the GDB command preceding point.
This is implemented using the GDB `complete' command which isn't
available with older versions of GDB."
  (interactive)
  (let* ((end (point))
	 (command (save-excursion
		    (beginning-of-line)
		    (and (looking-at comint-prompt-regexp)
			 (goto-char (match-end 0)))
		    (buffer-substring (point) end)))
	 command-word)
    ;; Find the word break.  This match will always succeed.
    (string-match "\\(\\`\\| \\)\\([^ ]*\\)\\'" command)
    (setq gud-gdb-complete-break (match-beginning 2)
	  command-word (substring command gud-gdb-complete-break))
    ;; Temporarily install our filter function.
    (let ((gud-marker-filter 'gud-gdb-complete-filter))
      ;; Issue the command to GDB.
      (gud-basic-call (concat "complete " command))
      (setq gud-gdb-complete-in-progress t
	    gud-gdb-complete-string nil
	    gud-gdb-complete-list nil)
      ;; Slurp the output.
      (while gud-gdb-complete-in-progress
	(accept-process-output (get-buffer-process gud-comint-buffer))))
    ;; Protect against old versions of GDB.
    (and gud-gdb-complete-list
	 (string-match "^Undefined command: \"complete\""
		       (car gud-gdb-complete-list))
	 (error "This version of GDB doesn't support the `complete' command."))
    ;; Sort the list like readline.
    (setq gud-gdb-complete-list
	  (sort gud-gdb-complete-list (function string-lessp)))
    ;; Remove duplicates.
    (let ((first gud-gdb-complete-list)
	  (second (cdr gud-gdb-complete-list)))
      (while second
	(if (string-equal (car first) (car second))
	    (setcdr first (setq second (cdr second)))
	  (setq first second
		second (cdr second)))))
    ;; Add a trailing single quote if there is a unique completion
    ;; and it contains an odd number of unquoted single quotes.
    (and (= (length gud-gdb-complete-list) 1)
	 (let ((str (car gud-gdb-complete-list))
	       (pos 0)
	       (count 0))
	   (while (string-match "\\([^'\\]\\|\\\\'\\)*'" str pos)
	     (setq count (1+ count)
		   pos (match-end 0)))
	   (and (= (mod count 2) 1)
		(setq gud-gdb-complete-list (list (concat str "'"))))))
    ;; Let comint handle the rest.
    (comint-dynamic-simple-complete command-word gud-gdb-complete-list)))
    
;; The completion process filter is installed temporarily to slurp the
;; output of GDB up to the next prompt and build the completion list.
(defun gud-gdb-complete-filter (string)
  (setq string (concat gud-gdb-complete-string string))
  (while (string-match "\n" string)
    (setq gud-gdb-complete-list
	  (cons (substring string gud-gdb-complete-break (match-beginning 0))
		gud-gdb-complete-list))
    (setq string (substring string (match-end 0))))
  (if (string-match comint-prompt-regexp string)
      (progn
	(setq gud-gdb-complete-in-progress nil)
	string)
    (progn
      (setq gud-gdb-complete-string string)
      "")))


;; ======================================================================
;; sdb functions

;;; History of argument lists passed to sdb.
(defvar gud-sdb-history nil)

(defvar gud-sdb-needs-tags (not (file-exists-p "/var"))
  "If nil, we're on a System V Release 4 and don't need the tags hack.")

(defvar gud-sdb-lastfile nil)

(defun gud-sdb-massage-args (file args) args)

(defun gud-sdb-marker-filter (string)
  (setq gud-marker-acc
	(if gud-marker-acc (concat gud-marker-acc string) string))
  (let (start)
    ;; Process all complete markers in this chunk
    (while 
	(cond 
	 ;; System V Release 3.2 uses this format
	 ((string-match "\\(^\\|\n\\)\\*?\\(0x\\w* in \\)?\\([^:\n]*\\):\\([0-9]*\\):.*\n"
			gud-marker-acc start)
	  (setq gud-last-frame
		(cons
		 (substring gud-marker-acc (match-beginning 3) (match-end 3))
		 (string-to-int 
		  (substring gud-marker-acc (match-beginning 4) (match-end 4))))))
	 ;; System V Release 4.0 quite often clumps two lines together
	 ((string-match "^\\(BREAKPOINT\\|STEPPED\\) process [0-9]+ function [^ ]+ in \\(.+\\)\n\\([0-9]+\\):" 
			gud-marker-acc start)
	  (setq gud-sdb-lastfile
		(substring gud-marker-acc (match-beginning 2) (match-end 2)))
	  (setq gud-last-frame
		(cons
		 gud-sdb-lastfile
		 (string-to-int 
		  (substring gud-marker-acc (match-beginning 3) (match-end 3))))))
	 ;; System V Release 4.0 
	 ((string-match "^\\(BREAKPOINT\\|STEPPED\\) process [0-9]+ function [^ ]+ in \\(.+\\)\n"
			gud-marker-acc start)
	  (setq gud-sdb-lastfile
		(substring gud-marker-acc (match-beginning 2) (match-end 2))))
	 ((and gud-sdb-lastfile (string-match "^\\([0-9]+\\):"
					      gud-marker-acc start))
	       (setq gud-last-frame
		     (cons
		      gud-sdb-lastfile
		      (string-to-int 
		       (substring gud-marker-acc (match-beginning 1) (match-end 1))))))
	 (t 
	  (setq gud-sdb-lastfile nil)))
      (setq start (match-end 0)))

    ;; Search for the last incomplete line in this chunk
    (while (string-match "\n" gud-marker-acc start)
      (setq start (match-end 0)))

    ;; If we have an incomplete line, store it in gud-marker-acc.
    (setq gud-marker-acc (substring gud-marker-acc (or start 0))))
  string)

(defun gud-sdb-find-file (f)
  (save-excursion
    (let ((buf (if gud-sdb-needs-tags
		   (find-tag-noselect f)
		 (find-file-noselect f))))
      (set-buffer buf)
      (gud-make-debug-menu)
      (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
      buf)))

;;;###autoload
(defun sdb (command-line)
  "Run sdb on program FILE in buffer *gud-FILE*.
The directory containing FILE becomes the initial working directory
and source-file directory for your debugger."
  (interactive
   (list (read-from-minibuffer "Run sdb (like this): "
			       (if (consp gud-sdb-history)
				   (car gud-sdb-history)
				 "sdb ")
			       nil nil
			       '(gud-sdb-history . 1))))
  (if (and gud-sdb-needs-tags
	   (not (and (boundp 'tags-file-name)
		     (stringp tags-file-name)
		     (file-exists-p tags-file-name))))
      (error "The sdb support requires a valid tags table to work."))

  (gud-common-init command-line 'gud-sdb-massage-args
		   'gud-sdb-marker-filter 'gud-sdb-find-file)

  (gud-def gud-break  "%l b" "\C-b"   "Set breakpoint at current line.")
  (gud-def gud-tbreak "%l c" "\C-t"   "Set temporary breakpoint at current line.")
  (gud-def gud-remove "%l d" "\C-d"   "Remove breakpoint at current line")
  (gud-def gud-step   "s %p" "\C-s"   "Step one source line with display.")
  (gud-def gud-stepi  "i %p" "\C-i"   "Step one instruction with display.")
  (gud-def gud-next   "S %p" "\C-n"   "Step one line (skip functions).")
  (gud-def gud-cont   "c"    "\C-r"   "Continue with display.")
  (gud-def gud-print  "%e/"  "\C-p"   "Evaluate C expression at point.")

  (setq comint-prompt-regexp  "\\(^\\|\n\\)\\*")
  (setq paragraph-start comint-prompt-regexp)
  (local-set-key [menu-bar debug tbreak]
    '("Temporary Breakpoint" . gud-tbreak))
  (run-hooks 'sdb-mode-hook)
  )

;; ======================================================================
;; dbx functions

;;; History of argument lists passed to dbx.
(defvar gud-dbx-history nil)

(defvar gud-dbx-directories nil
  "*A list of directories that dbx should search for source code.
If nil, only source files in the program directory
will be known to dbx.

The file names should be absolute, or relative to the directory
containing the executable being debugged.")

(defun gud-dbx-massage-args (file args)
  (nconc (let ((directories gud-dbx-directories)
	       (result nil))
	   (while directories
	     (setq result (cons (car directories) (cons "-I" result)))
	     (setq directories (cdr directories)))
	   (nreverse result))
	 args))

(defun gud-dbx-file-name (f)
  "Transform a relative file name to an absolute file name, for dbx."
  (let ((result nil))
    (if (file-exists-p f)
        (setq result (expand-file-name f))
      (let ((directories gud-dbx-directories))
        (while directories
          (let ((path (concat (car directories) "/" f)))
            (if (file-exists-p path)
                (setq result (expand-file-name path)
                      directories nil)))
          (setq directories (cdr directories)))))
    result))

(defun gud-dbx-marker-filter (string)
  (setq gud-marker-acc (if gud-marker-acc (concat gud-marker-acc string) string))

  (let (start)
    ;; Process all complete markers in this chunk.
    (while (or (string-match
		"stopped in .* at line \\([0-9]*\\) in file \"\\([^\"]*\\)\""
		gud-marker-acc start)
	       (string-match
		"signal .* in .* at line \\([0-9]*\\) in file \"\\([^\"]*\\)\""
		gud-marker-acc start))
      (setq gud-last-frame
	    (cons
	     (substring gud-marker-acc (match-beginning 2) (match-end 2))
	     (string-to-int 
	      (substring gud-marker-acc (match-beginning 1) (match-end 1))))
	    start (match-end 0)))

    ;; Search for the last incomplete line in this chunk
    (while (string-match "\n" gud-marker-acc start)
      (setq start (match-end 0)))

    ;; If the incomplete line APPEARS to begin with another marker, keep it
    ;; in the accumulator.  Otherwise, clear the accumulator to avoid an
    ;; unnecessary concat during the next call.
    (setq gud-marker-acc 
	  (if (string-match "\\(stopped\\|signal\\)" gud-marker-acc start)
	      (substring gud-marker-acc (match-beginning 0))
	    nil)))
  string)

;; Functions for Mips-style dbx.  Given the option `-emacs', documented in
;; OSF1, not necessarily elsewhere, it produces markers similar to gdb's.
(defvar gud-mips-p
  (or (string-match "^mips-[^-]*-ultrix" system-configuration)
      ;; We haven't tested gud on this system:
      (string-match "^mips-[^-]*-riscos" system-configuration)
      ;; It's documented on OSF/1.3
      (string-match "^mips-[^-]*-osf1" system-configuration)
      (string-match "^alpha-[^-]*-osf" system-configuration))
  "Non-nil to assume the MIPS/OSF dbx conventions (argument `-emacs').")

(defun gud-mipsdbx-massage-args (file args)
  (cons "-emacs" args))

;; This is just like the gdb one except for the regexps since we need to cope
;; with an optional breakpoint number in [] before the ^Z^Z
(defun gud-mipsdbx-marker-filter (string)
  (setq gud-marker-acc (concat gud-marker-acc string))
  (let ((output ""))

    ;; Process all the complete markers in this chunk.
    (while (string-match
	    ;; This is like th gdb marker but with an optional
	    ;; leading break point number like `[1] '
	    "[][ 0-9]*\032\032\\([^:\n]*\\):\\([0-9]*\\):.*\n"
	    gud-marker-acc)
      (setq

       ;; Extract the frame position from the marker.
       gud-last-frame
       (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
	     (string-to-int (substring gud-marker-acc
				       (match-beginning 2)
				       (match-end 2))))

       ;; Append any text before the marker to the output we're going
       ;; to return - we don't include the marker in this text.
       output (concat output
		      (substring gud-marker-acc 0 (match-beginning 0)))

       ;; Set the accumulator to the remaining text.
       gud-marker-acc (substring gud-marker-acc (match-end 0))))

    ;; Does the remaining text look like it might end with the
    ;; beginning of another marker?  If it does, then keep it in
    ;; gud-marker-acc until we receive the rest of it.  Since we
    ;; know the full marker regexp above failed, it's pretty simple to
    ;; test for marker starts.
    (if (string-match "[][ 0-9]*\032.*\\'" gud-marker-acc)
	(progn
	  ;; Everything before the potential marker start can be output.
	  (setq output (concat output (substring gud-marker-acc
						 0 (match-beginning 0))))

	  ;; Everything after, we save, to combine with later input.
	  (setq gud-marker-acc
		(substring gud-marker-acc (match-beginning 0))))

      (setq output (concat output gud-marker-acc)
	    gud-marker-acc ""))

    output))

;; The dbx in IRIX is a pain.  It doesn't print the file name when
;; stopping at a breakpoint (but you do get it from the `up' and
;; `down' commands...).  The only way to extract the information seems
;; to be with a `file' command, although the current line number is
;; available in $curline.  Thus we have to look for output which
;; appears to indicate a breakpoint.  Then we prod the dbx sub-process
;; to output the information we want with a combination of the
;; `printf' and `file' commands as a pseudo marker which we can
;; recognise next time through the marker-filter.  This would be like
;; the gdb marker but you can't get the file name without a newline...
;; Note that gud-remove won't work since Irix dbx expects a breakpoint
;; number rather than a line number etc.  Maybe this could be made to
;; work by listing all the breakpoints and picking the one(s) with the
;; correct line number, but life's too short.
;;   d.love@dl.ac.uk (Dave Love) can be blamed for this

(defvar gud-irix-p (string-match "^mips-[^-]*-irix" system-configuration)
  "Non-nil to assume the interface appropriate for IRIX dbx.
This works in IRIX 4, 5 and 6.")
;; [Irix dbx seems to be a moving target.  The dbx output changed
;; subtly sometime between OS v4.0.5 and v5.2 so that, for instance,
;; the output from `up' is no longer spotted by gud (and it's probably
;; not distinctive enough to try to match it -- use C-<, C->
;; exclusively) .  For 5.3 and 6.0, the $curline variable changed to
;; `long long'(why?!), so the printf stuff needed changing.  The line
;; number is cast to `long' as a compromise between the new `long
;; long' and the original `int'.  The process filter is also somewhat
;; unreliable, sometimes not spotting the markers; I don't know
;; whether there's anything that can be done about that.  It would be
;; much better if SGI could be persuaded to (re?)instate the MIPS
;; -emacs flag for gdb-like output (which ought to be possible as most
;; of the communication I've had over it has been from sgi.com).]

;; this filter is influenced by the xdb one rather than the gdb one
(defun gud-irixdbx-marker-filter (string)
  (let (result (case-fold-search nil))
    (if (or (string-match comint-prompt-regexp string)
	    (string-match ".*\012" string))
	(setq result (concat gud-marker-acc string)
	      gud-marker-acc "")
      (setq gud-marker-acc (concat gud-marker-acc string)))
    (if result
	(cond
	 ;; look for breakpoint or signal indication e.g.:
	 ;; [2] Process  1267 (pplot) stopped at [params:338 ,0x400ec0]
	 ;; Process  1281 (pplot) stopped at [params:339 ,0x400ec8]
	 ;; Process  1270 (pplot) Floating point exception [._read._read:16 ,0x452188]
	 ((string-match
	   "^\\(\\[[0-9]+] \\)?Process +[0-9]+ ([^)]*) [^[]+\\[[^]\n]*]\n" 
	   result)
	  ;; prod dbx into printing out the line number and file
	  ;; name in a form we can grok as below
	  (process-send-string (get-buffer-process gud-comint-buffer)
			       "printf \"\032\032%1d:\",(long)$curline;file\n"))
	 ;; look for result of, say, "up" e.g.:
	 ;; .pplot.pplot(0x800) ["src/pplot.f":261, 0x400c7c]
	 ;; (this will also catch one of the lines printed by "where")
	 ((string-match
	   "^[^ ][^[]*\\[\"\\([^\"]+\\)\":\\([0-9]+\\), [^]]+]\n"
	   result)
	  (let ((file (substring result (match-beginning 1)
				 (match-end 1))))
	    (if (file-exists-p file)
		(setq gud-last-frame
		      (cons
		       (substring
			result (match-beginning 1) (match-end 1))
		       (string-to-int 
			(substring
			 result (match-beginning 2) (match-end 2)))))))
	  result)
	 ((string-match			; kluged-up marker as above
	   "\032\032\\([0-9]*\\):\\(.*\\)\n" result)
	  (let ((file (gud-dbx-file-name
		       (substring result (match-beginning 2) (match-end 2)))))
	    (if (and file (file-exists-p file))
		(setq gud-last-frame
		      (cons
		       file
		       (string-to-int 
			(substring
			 result (match-beginning 1) (match-end 1)))))))
	  (setq result (substring result 0 (match-beginning 0))))))
    (or result "")))

(defun gud-dbx-find-file (f)
  (save-excursion
    (let ((realf (gud-dbx-file-name f)))
      (if realf
	  (let ((buf (find-file-noselect realf)))
	    (set-buffer buf)
	    (gud-make-debug-menu)
	    (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
	    (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
	    buf)
	nil))))

;;;###autoload
(defun dbx (command-line)
  "Run dbx on program FILE in buffer *gud-FILE*.
The directory containing FILE becomes the initial working directory
and source-file directory for your debugger."
  (interactive
   (list (read-from-minibuffer "Run dbx (like this): "
			       (if (consp gud-dbx-history)
				   (car gud-dbx-history)
				 "dbx ")
			       nil nil
			       '(gud-dbx-history . 1))))

  (cond
   (gud-mips-p
    (gud-common-init command-line 'gud-mipsdbx-massage-args
		     'gud-mipsdbx-marker-filter 'gud-dbx-find-file))
   (gud-irix-p
    (gud-common-init command-line 'gud-dbx-massage-args
		     'gud-irixdbx-marker-filter 'gud-dbx-find-file))
   (t
    (gud-common-init command-line 'gud-dbx-massage-args
		     'gud-dbx-marker-filter 'gud-dbx-find-file)))

  (cond
   (gud-mips-p
    (gud-def gud-up     "up %p"         "<" "Up (numeric arg) stack frames.")
    (gud-def gud-down   "down %p" ">" "Down (numeric arg) stack frames.")
    (gud-def gud-break "stop at \"%f\":%l"
				  "\C-b" "Set breakpoint at current line.")
    (gud-def gud-finish "return"  "\C-f" "Finish executing current function."))
   (gud-irix-p
    (gud-def gud-break "stop at \"%d%f\":%l"
				  "\C-b" "Set breakpoint at current line.")
    (gud-def gud-finish "return"  "\C-f" "Finish executing current function.")
    (gud-def gud-up     "up %p; printf \"\032\032%1ld:\",(long)$curline;file\n"
	     "<" "Up (numeric arg) stack frames.")
    (gud-def gud-down "down %p; printf \"\032\032%1ld:\",(long)$curline;file\n"
	     ">" "Down (numeric arg) stack frames.")
    ;; Make dbx give out the source location info that we need.
    (process-send-string (get-buffer-process gud-comint-buffer)
			 "printf \"\032\032%1d:\",(long)$curline;file\n"))
   (t
    (gud-def gud-up     "up %p"         "<" "Up (numeric arg) stack frames.")
    (gud-def gud-down   "down %p" ">" "Down (numeric arg) stack frames.")
    (gud-def gud-break "file \"%d%f\"\nstop at %l"
				  "\C-b" "Set breakpoint at current line.")))

  (gud-def gud-remove "clear %l"  "\C-d" "Remove breakpoint at current line")
  (gud-def gud-step   "step %p"	  "\C-s" "Step one line with display.")
  (gud-def gud-stepi  "stepi %p"  "\C-i" "Step one instruction with display.")
  (gud-def gud-next   "next %p"	  "\C-n" "Step one line (skip functions).")
  (gud-def gud-cont   "cont"	  "\C-r" "Continue with display.")
  (gud-def gud-print  "print %e"  "\C-p" "Evaluate C expression at point.")

  (setq comint-prompt-regexp  "^[^)\n]*dbx) *")
  (setq paragraph-start comint-prompt-regexp)
  (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
  (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
  (run-hooks 'dbx-mode-hook)
  )

;; ======================================================================
;; xdb (HP PARISC debugger) functions

;;; History of argument lists passed to xdb.
(defvar gud-xdb-history nil)

(defvar gud-xdb-directories nil
  "*A list of directories that xdb should search for source code.
If nil, only source files in the program directory
will be known to xdb.

The file names should be absolute, or relative to the directory
containing the executable being debugged.")

(defun gud-xdb-massage-args (file args)
  (nconc (let ((directories gud-xdb-directories)
	       (result nil))
	   (while directories
	     (setq result (cons (car directories) (cons "-d" result)))
	     (setq directories (cdr directories)))
	   (nreverse result))
	 args))

(defun gud-xdb-file-name (f)
  "Transform a relative pathname to a full pathname in xdb mode"
  (let ((result nil))
    (if (file-exists-p f)
        (setq result (expand-file-name f))
      (let ((directories gud-xdb-directories))
        (while directories
          (let ((path (concat (car directories) "/" f)))
            (if (file-exists-p path)
                (setq result (expand-file-name path)
                      directories nil)))
          (setq directories (cdr directories)))))
    result))

;; xdb does not print the lines all at once, so we have to accumulate them
(defun gud-xdb-marker-filter (string)
  (let (result)
    (if (or (string-match comint-prompt-regexp string)
            (string-match ".*\012" string))
        (setq result (concat gud-marker-acc string)
              gud-marker-acc "")
      (setq gud-marker-acc (concat gud-marker-acc string)))
    (if result
        (if (or (string-match "\\([^\n \t:]+\\): [^:]+: \\([0-9]+\\)[: ]"
			      result)
                (string-match "[^: \t]+:[ \t]+\\([^:]+\\): [^:]+: \\([0-9]+\\):"
                              result))
            (let ((line (string-to-int
                         (substring result (match-beginning 2) (match-end 2))))
                  (file (gud-xdb-file-name
                         (substring result (match-beginning 1) (match-end 1)))))
              (if file
                  (setq gud-last-frame (cons file line))))))
    (or result "")))    
               
(defun gud-xdb-find-file (f)
  (save-excursion
    (let ((realf (gud-xdb-file-name f)))
      (if realf
	  (let ((buf (find-file-noselect realf)))
	    (set-buffer buf)
	    (gud-make-debug-menu)
	    (local-set-key [menu-bar debug tbreak]
			   '("Temporary Breakpoint" . gud-tbreak))
	    (local-set-key [menu-bar debug finish]
			   '("Finish Function" . gud-finish))
	    (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
	    (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
	    buf)
	nil))))

;;;###autoload
(defun xdb (command-line)
  "Run xdb on program FILE in buffer *gud-FILE*.
The directory containing FILE becomes the initial working directory
and source-file directory for your debugger.

You can set the variable 'gud-xdb-directories' to a list of program source
directories if your program contains sources from more than one directory."
  (interactive
   (list (read-from-minibuffer "Run xdb (like this): "
			       (if (consp gud-xdb-history)
				   (car gud-xdb-history)
				 "xdb ")
			       nil nil
			       '(gud-xdb-history . 1))))

  (gud-common-init command-line 'gud-xdb-massage-args
		   'gud-xdb-marker-filter 'gud-xdb-find-file)

  (gud-def gud-break  "b %f:%l"    "\C-b" "Set breakpoint at current line.")
  (gud-def gud-tbreak "b %f:%l\\t" "\C-t"
           "Set temporary breakpoint at current line.")
  (gud-def gud-remove "db"         "\C-d" "Remove breakpoint at current line")
  (gud-def gud-step   "s %p"	   "\C-s" "Step one line with display.")
  (gud-def gud-next   "S %p"	   "\C-n" "Step one line (skip functions).")
  (gud-def gud-cont   "c"	   "\C-r" "Continue with display.")
  (gud-def gud-up     "up %p"	   "<"    "Up (numeric arg) stack frames.")
  (gud-def gud-down   "down %p"	   ">"    "Down (numeric arg) stack frames.")
  (gud-def gud-finish "bu\\t"      "\C-f" "Finish executing current function.")
  (gud-def gud-print  "p %e"       "\C-p" "Evaluate C expression at point.")

  (setq comint-prompt-regexp  "^>")
  (setq paragraph-start comint-prompt-regexp)
  (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
  (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
  (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
  (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
  (run-hooks 'xdb-mode-hook))

;; ======================================================================
;; perldb functions

;;; History of argument lists passed to perldb.
(defvar gud-perldb-history nil)

(defun gud-perldb-massage-args (file args)
  (cons "-d" (cons (car args) (cons "-emacs" (cdr args)))))

;; There's no guarantee that Emacs will hand the filter the entire
;; marker at once; it could be broken up across several strings.  We
;; might even receive a big chunk with several markers in it.  If we
;; receive a chunk of text which looks like it might contain the
;; beginning of a marker, we save it here between calls to the
;; filter.
(defvar gud-perldb-marker-acc "")

(defun gud-perldb-marker-filter (string)
  (setq gud-marker-acc (concat gud-marker-acc string))
  (let ((output ""))

    ;; Process all the complete markers in this chunk.
    (while (string-match "\032\032\\([^:\n]*\\):\\([0-9]*\\):.*\n"
			 gud-marker-acc)
      (setq

       ;; Extract the frame position from the marker.
       gud-last-frame
       (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
	     (string-to-int (substring gud-marker-acc
				       (match-beginning 2)
				       (match-end 2))))

       ;; Append any text before the marker to the output we're going
       ;; to return - we don't include the marker in this text.
       output (concat output
		      (substring gud-marker-acc 0 (match-beginning 0)))

       ;; Set the accumulator to the remaining text.
       gud-marker-acc (substring gud-marker-acc (match-end 0))))

    ;; Does the remaining text look like it might end with the
    ;; beginning of another marker?  If it does, then keep it in
    ;; gud-marker-acc until we receive the rest of it.  Since we
    ;; know the full marker regexp above failed, it's pretty simple to
    ;; test for marker starts.
    (if (string-match "\032.*\\'" gud-marker-acc)
	(progn
	  ;; Everything before the potential marker start can be output.
	  (setq output (concat output (substring gud-marker-acc
						 0 (match-beginning 0))))

	  ;; Everything after, we save, to combine with later input.
	  (setq gud-marker-acc
		(substring gud-marker-acc (match-beginning 0))))

      (setq output (concat output gud-marker-acc)
	    gud-marker-acc ""))

    output))

(defun gud-perldb-find-file (f)
  (save-excursion
    (let ((buf (find-file-noselect f)))
      (set-buffer buf)
      (gud-make-debug-menu)
      buf)))

;;;###autoload
(defun perldb (command-line)
  "Run perldb on program FILE in buffer *gud-FILE*.
The directory containing FILE becomes the initial working directory
and source-file directory for your debugger."
  (interactive
   (list (read-from-minibuffer "Run perldb (like this): "
			       (if (consp gud-perldb-history)
				   (car gud-perldb-history)
				 "perl ")
			       nil nil
			       '(gud-perldb-history . 1))))

  (gud-common-init command-line 'gud-perldb-massage-args
		   'gud-perldb-marker-filter 'gud-perldb-find-file)

  (gud-def gud-break  "b %l"         "\C-b" "Set breakpoint at current line.")
  (gud-def gud-remove "d %l"         "\C-d" "Remove breakpoint at current line")
  (gud-def gud-step   "s"            "\C-s" "Step one source line with display.")
  (gud-def gud-next   "n"            "\C-n" "Step one line (skip functions).")
  (gud-def gud-cont   "c"            "\C-r" "Continue with display.")
;  (gud-def gud-finish "finish"       "\C-f" "Finish executing current function.")
;  (gud-def gud-up     "up %p"        "<" "Up N stack frames (numeric arg).")
;  (gud-def gud-down   "down %p"      ">" "Down N stack frames (numeric arg).")
  (gud-def gud-print  "%e"           "\C-p" "Evaluate perl expression at point.")

  (setq comint-prompt-regexp "^  DB<[0-9]+> ")
  (setq paragraph-start comint-prompt-regexp)
  (run-hooks 'perldb-mode-hook)
  )

;;
;; End of debugger-specific information
;;


;;; When we send a command to the debugger via gud-call, it's annoying
;;; to see the command and the new prompt inserted into the debugger's
;;; buffer; we have other ways of knowing the command has completed.
;;;
;;; If the buffer looks like this:
;;; --------------------
;;; (gdb) set args foo bar
;;; (gdb) -!-
;;; --------------------
;;; (the -!- marks the location of point), and we type `C-x SPC' in a
;;; source file to set a breakpoint, we want the buffer to end up like
;;; this:
;;; --------------------
;;; (gdb) set args foo bar
;;; Breakpoint 1 at 0x92: file make-docfile.c, line 49.
;;; (gdb) -!-
;;; --------------------
;;; Essentially, the old prompt is deleted, and the command's output
;;; and the new prompt take its place.
;;;
;;; Not echoing the command is easy enough; you send it directly using
;;; process-send-string, and it never enters the buffer.  However,
;;; getting rid of the old prompt is trickier; you don't want to do it
;;; when you send the command, since that will result in an annoying
;;; flicker as the prompt is deleted, redisplay occurs while Emacs
;;; waits for a response from the debugger, and the new prompt is
;;; inserted.  Instead, we'll wait until we actually get some output
;;; from the subprocess before we delete the prompt.  If the command
;;; produced no output other than a new prompt, that prompt will most
;;; likely be in the first chunk of output received, so we will delete
;;; the prompt and then replace it with an identical one.  If the
;;; command produces output, the prompt is moving anyway, so the
;;; flicker won't be annoying.
;;;
;;; So - when we want to delete the prompt upon receipt of the next
;;; chunk of debugger output, we position gud-delete-prompt-marker at
;;; the start of the prompt; the process filter will notice this, and
;;; delete all text between it and the process output marker.  If
;;; gud-delete-prompt-marker points nowhere, we leave the current
;;; prompt alone.
(defvar gud-delete-prompt-marker nil)


(defun gud-mode ()
  "Major mode for interacting with an inferior debugger process.

   You start it up with one of the commands M-x gdb, M-x sdb, M-x dbx,
or M-x xdb.  Each entry point finishes by executing a hook; `gdb-mode-hook',
`sdb-mode-hook', `dbx-mode-hook' or `xdb-mode-hook' respectively.

After startup, the following commands are available in both the GUD
interaction buffer and any source buffer GUD visits due to a breakpoint stop
or step operation:

\\[gud-break] sets a breakpoint at the current file and line.  In the
GUD buffer, the current file and line are those of the last breakpoint or
step.  In a source buffer, they are the buffer's file and current line.

\\[gud-remove] removes breakpoints on the current file and line.

\\[gud-refresh] displays in the source window the last line referred to
in the gud buffer.

\\[gud-step], \\[gud-next], and \\[gud-stepi] do a step-one-line,
step-one-line (not entering function calls), and step-one-instruction
and then update the source window with the current file and position.
\\[gud-cont] continues execution.

\\[gud-print] tries to find the largest C lvalue or function-call expression
around point, and sends it to the debugger for value display.

The above commands are common to all supported debuggers except xdb which
does not support stepping instructions.

Under gdb, sdb and xdb, \\[gud-tbreak] behaves exactly like \\[gud-break],
except that the breakpoint is temporary; that is, it is removed when
execution stops on it.

Under gdb, dbx, and xdb, \\[gud-up] pops up through an enclosing stack
frame.  \\[gud-down] drops back down through one.

If you are using gdb or xdb, \\[gud-finish] runs execution to the return from
the current function and stops.

All the keystrokes above are accessible in the GUD buffer
with the prefix C-c, and in all buffers through the prefix C-x C-a.

All pre-defined functions for which the concept make sense repeat
themselves the appropriate number of times if you give a prefix
argument.

You may use the `gud-def' macro in the initialization hook to define other
commands.

Other commands for interacting with the debugger process are inherited from
comint mode, which see."
  (interactive)
  (comint-mode)
  (setq major-mode 'gud-mode)
  (setq mode-name "Debugger")
  (setq mode-line-process '(":%s"))
  (use-local-map comint-mode-map)
  (gud-make-debug-menu)
  (define-key (current-local-map) "\C-c\C-l" 'gud-refresh)
  (make-local-variable 'gud-last-frame)
  (setq gud-last-frame nil)
  (make-local-variable 'comint-prompt-regexp)
  (make-local-variable 'paragraph-start)
  (make-local-variable 'gud-delete-prompt-marker)
  (setq gud-delete-prompt-marker (make-marker))
  (run-hooks 'gud-mode-hook))

;; Chop STRING into words separated by SPC or TAB and return a list of them.
(defun gud-chop-words (string)
  (let ((i 0) (beg 0)
	(len (length string))
	(words nil))
    (while (< i len)
      (if (memq (aref string i) '(?\t ? ))
	  (progn
	    (setq words (cons (substring string beg i) words)
		  beg (1+ i))
	    (while (and (< beg len) (memq (aref string beg) '(?\t ? )))
	      (setq beg (1+ beg)))
	    (setq i (1+ beg)))
	(setq i (1+ i))))
    (if (< beg len)
	(setq words (cons (substring string beg) words)))
    (nreverse words)))

;; Perform initializations common to all debuggers.
;; The first arg is the specified command line,
;; which starts with the program to debug.
;; The other three args specify the values to use
;; for local variables in the debugger buffer.
(defun gud-common-init (command-line massage-args marker-filter find-file)
  (let* ((words (gud-chop-words command-line))
	 (program (car words))
	 ;; Extract the file name from WORDS
	 ;; and put t in its place.
	 ;; Later on we will put the modified file name arg back there.
	 (file-word (let ((w (cdr words)))
		      (while (and w (= ?- (aref (car w) 0)))
			(setq w (cdr w)))
		      (and w
			   (prog1 (car w)
			     (setcar w t)))))
	 (file-subst
	  (and file-word (substitute-in-file-name file-word)))
	 (args (cdr words))
	 ;; If a directory was specified, expand the file name.
	 ;; Otherwise, don't expand it, so GDB can use the PATH.
	 ;; A file name without directory is literally valid
	 ;; only if the file exists in ., and in that case,
	 ;; omitting the expansion here has no visible effect.
	 (file (and file-word
		    (if (file-name-directory file-subst)
			(expand-file-name file-subst)
		      file-subst)))
	 (filepart (and file-word (concat "-" (file-name-nondirectory file)))))
    (switch-to-buffer (concat "*gud" filepart "*"))
    ;; Set default-directory to the file's directory.
    (and file-word
	 ;; Don't set default-directory if no directory was specified.
	 ;; In that case, either the file is found in the current directory,
	 ;; in which case this setq is a no-op,
	 ;; or it is found by searching PATH,
	 ;; in which case we don't know what directory it was found in.
	 (file-name-directory file)
	 (setq default-directory (file-name-directory file)))
    (or (bolp) (newline))
    (insert "Current directory is " default-directory "\n")
    ;; Put the substituted and expanded file name back in its place.
    (let ((w args))
      (while (and w (not (eq (car w) t)))
	(setq w (cdr w)))
      (if w
	  (setcar w file)))
    (apply 'make-comint (concat "gud" filepart) program nil
	   (funcall massage-args file args)))
  ;; Since comint clobbered the mode, we don't set it until now.
  (gud-mode)
  (make-local-variable 'gud-marker-filter)
  (setq gud-marker-filter marker-filter)
  (make-local-variable 'gud-find-file)
  (setq gud-find-file find-file)

  (set-process-filter (get-buffer-process (current-buffer)) 'gud-filter)
  (set-process-sentinel (get-buffer-process (current-buffer)) 'gud-sentinel)
  (gud-set-buffer)
  )

(defun gud-set-buffer ()
  (cond ((eq major-mode 'gud-mode)
	(setq gud-comint-buffer (current-buffer)))))

(defvar gud-filter-defer-flag nil
  "Non-nil means don't process anything from the debugger right now.
It is saved for when this flag is not set.")

(defvar gud-filter-pending-text nil
  "Non-nil means this is text that has been saved for later in `gud-filter'.")

;; These functions are responsible for inserting output from your debugger
;; into the buffer.  The hard work is done by the method that is
;; the value of gud-marker-filter.

(defun gud-filter (proc string)
  ;; Here's where the actual buffer insertion is done
  (let (output process-window)
    (if (buffer-name (process-buffer proc))
	(if gud-filter-defer-flag
	    ;; If we can't process any text now,
	    ;; save it for later.
	    (setq gud-filter-pending-text
		  (concat (or gud-filter-pending-text "") string))
	  (save-excursion
	    ;; If we have to ask a question during the processing,
	    ;; defer any additional text that comes from the debugger
	    ;; during that time.
	    (let ((gud-filter-defer-flag t))
	      ;; Process now any text we previously saved up.
	      (if gud-filter-pending-text
		  (setq string (concat gud-filter-pending-text string)
			gud-filter-pending-text nil))
	      (set-buffer (process-buffer proc))
	      ;; If we have been so requested, delete the debugger prompt.
	      (if (marker-buffer gud-delete-prompt-marker)
		  (progn
		    (delete-region (process-mark proc) gud-delete-prompt-marker)
		    (set-marker gud-delete-prompt-marker nil)))
	      ;; Save the process output, checking for source file markers.
	      (setq output (gud-marker-filter string))
	      ;; Check for a filename-and-line number.
	      ;; Don't display the specified file
	      ;; unless (1) point is at or after the position where output appears
	      ;; and (2) this buffer is on the screen.
	      (setq process-window
		    (and gud-last-frame
			 (>= (point) (process-mark proc))
			 (get-buffer-window (current-buffer)))))
	    (if process-window
		(save-selected-window
		  (select-window process-window)
		  (gud-display-frame)))

	    ;; Let the comint filter do the actual insertion.
	    ;; That lets us inherit various comint features.
	    (comint-output-filter proc output)

	    ;; If we deferred text that arrived during this processing,
	    ;; handle it now.
	    (if gud-filter-pending-text
		(gud-filter proc "")))))))

(defun gud-sentinel (proc msg)
  (cond ((null (buffer-name (process-buffer proc)))
	 ;; buffer killed
	 ;; Stop displaying an arrow in a source file.
	 (setq overlay-arrow-position nil)
	 (set-process-buffer proc nil))
	((memq (process-status proc) '(signal exit))
	 ;; Stop displaying an arrow in a source file.
	 (setq overlay-arrow-position nil)
	 ;; Fix the mode line.
	 (setq mode-line-process
	       (concat ":"
		       (symbol-name (process-status proc))))
	 (let* ((obuf (current-buffer)))
	   ;; save-excursion isn't the right thing if
	   ;;  process-buffer is current-buffer
	   (unwind-protect
	       (progn
		 ;; Write something in *compilation* and hack its mode line,
		 (set-buffer (process-buffer proc))
		 (force-mode-line-update)
		 (if (eobp)
		     (insert ?\n mode-name " " msg)
		   (save-excursion
		     (goto-char (point-max))
		     (insert ?\n mode-name " " msg)))
		 ;; If buffer and mode line will show that the process
		 ;; is dead, we can delete it now.  Otherwise it
		 ;; will stay around until M-x list-processes.
		 (delete-process proc))
	     ;; Restore old buffer, but don't restore old point
	     ;; if obuf is the gud buffer.
	     (set-buffer obuf))))))

(defun gud-display-frame ()
  "Find and obey the last filename-and-line marker from the debugger.
Obeying it means displaying in another window the specified file and line."
  (interactive)
  (if gud-last-frame
   (progn
     (gud-set-buffer)
     (gud-display-line (car gud-last-frame) (cdr gud-last-frame))
     (setq gud-last-last-frame gud-last-frame
	   gud-last-frame nil))))

;; Make sure the file named TRUE-FILE is in a buffer that appears on the screen
;; and that its line LINE is visible.
;; Put the overlay-arrow on the line LINE in that buffer.
;; Most of the trickiness in here comes from wanting to preserve the current
;; region-restriction if that's possible.  We use an explicit display-buffer
;; to get around the fact that this is called inside a save-excursion.

(defun gud-display-line (true-file line)
  (let* ((last-nonmenu-event t)	 ; Prevent use of dialog box for questions.
	 (buffer (gud-find-file true-file))
	 (window (display-buffer buffer))
	 (pos))
;;;    (if (equal buffer (current-buffer))
;;;	nil
;;;      (setq buffer-read-only nil))
    (save-excursion
;;;      (setq buffer-read-only t)
      (set-buffer buffer)
      (save-restriction
	(widen)
	(goto-line line)
	(setq pos (point))
	(setq overlay-arrow-string "=>")
	(or overlay-arrow-position
	    (setq overlay-arrow-position (make-marker)))
	(set-marker overlay-arrow-position (point) (current-buffer)))
      (cond ((or (< pos (point-min)) (> pos (point-max)))
	     (widen)
	     (goto-char pos))))
    (set-window-point window overlay-arrow-position)))

;;; The gud-call function must do the right thing whether its invoking
;;; keystroke is from the GUD buffer itself (via major-mode binding)
;;; or a C buffer.  In the former case, we want to supply data from
;;; gud-last-frame.  Here's how we do it:

(defun gud-format-command (str arg)
  (let ((insource (not (eq (current-buffer) gud-comint-buffer)))
	(frame (or gud-last-frame gud-last-last-frame))
	result)
    (while (and str (string-match "\\([^%]*\\)%\\([adeflp]\\)" str))
      (let ((key (string-to-char (substring str (match-beginning 2))))
	    subst)
	(cond
	 ((eq key ?f)
	  (setq subst (file-name-nondirectory (if insource
						  (buffer-file-name)
						(car frame)))))
	 ((eq key ?d)
	  (setq subst (file-name-directory (if insource
					       (buffer-file-name)
					     (car frame)))))
	 ((eq key ?l)
	  (setq subst (if insource
			  (save-excursion
			    (beginning-of-line)
			    (save-restriction (widen) 
					      (1+ (count-lines 1 (point)))))
			(cdr frame))))
	 ((eq key ?e)
	  (setq subst (find-c-expr)))
	 ((eq key ?a)
	  (setq subst (gud-read-address)))
	 ((eq key ?p)
	  (setq subst (if arg (int-to-string arg) ""))))
	(setq result (concat result
			     (substring str (match-beginning 1) (match-end 1))
			     subst)))
      (setq str (substring str (match-end 2))))
    ;; There might be text left in STR when the loop ends.
    (concat result str)))

(defun gud-read-address ()
  "Return a string containing the core-address found in the buffer at point."
  (save-excursion
    (let ((pt (point)) found begin)
      (setq found (if (search-backward "0x" (- pt 7) t) (point)))
      (cond
       (found (forward-char 2)
	      (buffer-substring found
				(progn (re-search-forward "[^0-9a-f]")
				       (forward-char -1)
				       (point))))
       (t (setq begin (progn (re-search-backward "[^0-9]") 
			     (forward-char 1)
			     (point)))
	  (forward-char 1)
	  (re-search-forward "[^0-9]")
	  (forward-char -1)
	  (buffer-substring begin (point)))))))

(defun gud-call (fmt &optional arg)
  (let ((msg (gud-format-command fmt arg)))
    (message "Command: %s" msg)
    (sit-for 0)
    (gud-basic-call msg)))

(defun gud-basic-call (command)
  "Invoke the debugger COMMAND displaying source in other window."
  (interactive)
  (gud-set-buffer)
  (let ((command (concat command "\n"))
	(proc (get-buffer-process gud-comint-buffer)))
    (or proc (error "Current buffer has no process"))
    ;; Arrange for the current prompt to get deleted.
    (save-excursion
      (set-buffer gud-comint-buffer)
      (goto-char (process-mark proc))
      (beginning-of-line)
      (if (looking-at comint-prompt-regexp)
	  (set-marker gud-delete-prompt-marker (point))))
    (process-send-string proc command)))

(defun gud-refresh (&optional arg)
  "Fix up a possibly garbled display, and redraw the arrow."
  (interactive "P")
  (recenter arg)
  (or gud-last-frame (setq gud-last-frame gud-last-last-frame))
  (gud-display-frame))

;;; Code for parsing expressions out of C code.  The single entry point is
;;; find-c-expr, which tries to return an lvalue expression from around point.
;;;
;;; The rest of this file is a hacked version of gdbsrc.el by
;;; Debby Ayers <ayers@asc.slb.com>,
;;; Rich Schaefer <schaefer@asc.slb.com> Schlumberger, Austin, Tx.

(defun find-c-expr ()
  "Returns the C expr that surrounds point."
  (interactive)
  (save-excursion
    (let ((p) (expr) (test-expr))
      (setq p (point))
      (setq expr (expr-cur))
      (setq test-expr (expr-prev))
      (while (expr-compound test-expr expr)
	(setq expr (cons (car test-expr) (cdr expr)))
	(goto-char (car expr))
	(setq test-expr (expr-prev)))
      (goto-char p)
      (setq test-expr (expr-next))
      (while (expr-compound expr test-expr)
	(setq expr (cons (car expr) (cdr test-expr)))
	(setq test-expr (expr-next))
	)
      (buffer-substring (car expr) (cdr expr)))))

(defun expr-cur ()
  "Returns the expr that point is in; point is set to beginning of expr.
The expr is represented as a cons cell, where the car specifies the point in
the current buffer that marks the beginning of the expr and the cdr specifies 
the character after the end of the expr."
  (let ((p (point)) (begin) (end))
    (expr-backward-sexp)
    (setq begin (point))
    (expr-forward-sexp)
    (setq end (point))
    (if (>= p end) 
	(progn
	 (setq begin p)
	 (goto-char p)
	 (expr-forward-sexp)
	 (setq end (point))
	 )
      )
    (goto-char begin)
    (cons begin end)))

(defun expr-backward-sexp ()
  "Version of `backward-sexp' that catches errors."
  (condition-case nil
      (backward-sexp)
    (error t)))

(defun expr-forward-sexp ()
  "Version of `forward-sexp' that catches errors."
  (condition-case nil
     (forward-sexp)
    (error t)))

(defun expr-prev ()
  "Returns the previous expr, point is set to beginning of that expr.
The expr is represented as a cons cell, where the car specifies the point in
the current buffer that marks the beginning of the expr and the cdr specifies 
the character after the end of the expr"
  (let ((begin) (end))
    (expr-backward-sexp)
    (setq begin (point))
    (expr-forward-sexp)
    (setq end (point))
    (goto-char begin)
    (cons begin end)))

(defun expr-next ()
  "Returns the following expr, point is set to beginning of that expr.
The expr is represented as a cons cell, where the car specifies the point in
the current buffer that marks the beginning of the expr and the cdr specifies 
the character after the end of the expr."
  (let ((begin) (end))
    (expr-forward-sexp)
    (expr-forward-sexp)
    (setq end (point))
    (expr-backward-sexp)
    (setq begin (point))
    (cons begin end)))

(defun expr-compound-sep (span-start span-end)
  "Returns '.' for '->' & '.', returns ' ' for white space,
returns '?' for other punctuation."
  (let ((result ? )
	(syntax))
    (while (< span-start span-end)
      (setq syntax (char-syntax (char-after span-start)))
      (cond
       ((= syntax ? ) t)
       ((= syntax ?.) (setq syntax (char-after span-start))
	(cond 
	 ((= syntax ?.) (setq result ?.))
	 ((and (= syntax ?-) (= (char-after (+ span-start 1)) ?>))
	  (setq result ?.)
	  (setq span-start (+ span-start 1)))
	 (t (setq span-start span-end)
	    (setq result ??)))))
      (setq span-start (+ span-start 1)))
    result))

(defun expr-compound (first second)
  "Non-nil if concatenating FIRST and SECOND makes a single C token.
The two exprs are represented as a cons cells, where the car 
specifies the point in the current buffer that marks the beginning of the 
expr and the cdr specifies the character after the end of the expr.
Link exprs of the form:
      Expr -> Expr
      Expr . Expr
      Expr (Expr)
      Expr [Expr]
      (Expr) Expr
      [Expr] Expr"
  (let ((span-start (cdr first))
	(span-end (car second))
	(syntax))
    (setq syntax (expr-compound-sep span-start span-end))
    (cond
     ((= (car first) (car second)) nil)
     ((= (cdr first) (cdr second)) nil)
     ((= syntax ?.) t)
     ((= syntax ? )
	 (setq span-start (char-after (- span-start 1)))
	 (setq span-end (char-after span-end))
	 (cond
	  ((= span-start ?) ) t )
	  ((= span-start ?] ) t )
          ((= span-end ?( ) t )
	  ((= span-end ?[ ) t )
	  (t nil))
	 )
     (t nil))))

(provide 'gud)

;;; gud.el ends here