summaryrefslogtreecommitdiff
path: root/gcc/tree-browser.c
blob: c3483a7b3a7c71a43a8ab21686f20c521801dbb3 (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
/* Tree browser.
   Copyright (C) 2002-2013 Free Software Foundation, Inc.
   Contributed by Sebastian Pop <s.pop@laposte.net>

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

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

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "hash-table.h"
#include "tree.h"
#include "tree-pretty-print.h"
#include "print-tree.h"

#define TB_OUT_FILE stdout
#define TB_IN_FILE stdin
#define TB_NIY fprintf (TB_OUT_FILE, "Sorry this command is not yet implemented.\n")
#define TB_WF fprintf (TB_OUT_FILE, "Warning, this command failed.\n")

/* Structures for handling Tree Browser's commands.  */
#define DEFTBCODE(COMMAND, STRING, HELP)   COMMAND,
enum TB_Comm_code {
#include "tree-browser.def"
  TB_UNUSED_COMMAND
};
#undef DEFTBCODE
typedef enum TB_Comm_code TB_CODE;

struct tb_command {
  const char *help_msg;
  const char *comm_text;
  size_t comm_len;
  TB_CODE comm_code;
};

#define DEFTBCODE(code, str, help) { help, str, sizeof (str) - 1, code },
static const struct tb_command tb_commands[] =
{
#include "tree-browser.def"
};
#undef DEFTBCODE

#define TB_COMMAND_LEN(N) (tb_commands[N].comm_len)
#define TB_COMMAND_TEXT(N) (tb_commands[N].comm_text)
#define TB_COMMAND_CODE(N) (tb_commands[N].comm_code)
#define TB_COMMAND_HELP(N) (tb_commands[N].help_msg)


/* Next structure is for parsing TREE_CODEs.  */
struct tb_tree_code {
  enum tree_code code;
  const char *code_string;
  size_t code_string_len;
};

#define DEFTREECODE(SYM, STRING, TYPE, NARGS) { SYM, STRING, sizeof (STRING) - 1 },
#define END_OF_BASE_TREE_CODES \
  { LAST_AND_UNUSED_TREE_CODE, "@dummy", sizeof ("@dummy") - 1 },
static const struct tb_tree_code tb_tree_codes[] =
{
#include "all-tree.def"
};
#undef DEFTREECODE
#undef END_OF_BASE_TREE_CODES

#define TB_TREE_CODE(N) (tb_tree_codes[N].code)
#define TB_TREE_CODE_TEXT(N) (tb_tree_codes[N].code_string)
#define TB_TREE_CODE_LEN(N) (tb_tree_codes[N].code_string_len)


/* Function declarations.  */

static long TB_getline (char **, long *, FILE *);
static TB_CODE TB_get_command (char *);
static enum tree_code TB_get_tree_code (char *);
static tree find_node_with_code (tree *, int *, void *);
static tree store_child_info (tree *, int *, void *);
static void TB_update_up (tree);
static tree TB_current_chain_node (tree);
static tree TB_prev_expr (tree);
static tree TB_next_expr (tree);
static tree TB_up_expr (tree);
static tree TB_first_in_bind (tree);
static tree TB_last_in_bind (tree);
static tree TB_history_prev (void);

/* FIXME: To be declared in a .h file.  */
void browse_tree (tree);

/* Hashtable helpers.  */
struct tree_upper_hasher : typed_noop_remove <tree_node>
{
  typedef tree_node value_type;
  typedef tree_node compare_type;
  static inline hashval_t hash (const value_type *);
  static inline bool equal (const value_type *, const compare_type *);
};

inline hashval_t
tree_upper_hasher::hash (const value_type *v)
{
  return pointer_hash <value_type>::hash (v);
}

inline bool
tree_upper_hasher::equal (const value_type *parent, const compare_type *node)
{
  if (parent == NULL || node == NULL)
    return 0;

  if (EXPR_P (parent))
    {
      int n = TREE_OPERAND_LENGTH (parent);
      int i;
      for (i = 0; i < n; i++)
	if (node == TREE_OPERAND (parent, i))
	  return true;
    }
  return false;
}

/* Static variables.  */
static hash_table <tree_upper_hasher> TB_up_ht;
static vec<tree, va_gc> *TB_history_stack;
static int TB_verbose = 1;


/* Entry point in the Tree Browser.  */

void
browse_tree (tree begin)
{
  tree head;
  TB_CODE tbc = TB_UNUSED_COMMAND;
  ssize_t rd;
  char *input = NULL;
  long input_size = 0;

  fprintf (TB_OUT_FILE, "\nTree Browser\n");

#define TB_SET_HEAD(N) do {                                           \
  vec_safe_push (TB_history_stack, N);                                \
  head = N;                                                           \
  if (TB_verbose)                                                     \
    if (head)                                                         \
      {                                                               \
	print_generic_expr (TB_OUT_FILE, head, 0);                    \
	fprintf (TB_OUT_FILE, "\n");                                  \
      }                                                               \
} while (0)

  TB_SET_HEAD (begin);

  /* Store in a hashtable information about previous and upper statements.  */
  {
    TB_up_ht.create (1023);
    TB_update_up (head);
  }

  while (24)
    {
      fprintf (TB_OUT_FILE, "TB> ");
      rd = TB_getline (&input, &input_size, TB_IN_FILE);

      if (rd == -1)
	/* EOF.  */
	goto ret;

      if (rd != 1)
	/* Get a new command.  Otherwise the user just pressed enter, and thus
	   she expects the last command to be reexecuted.  */
	tbc = TB_get_command (input);

      switch (tbc)
	{
	case TB_UPDATE_UP:
	  TB_update_up (head);
	  break;

	case TB_MAX:
	  if (head && (INTEGRAL_TYPE_P (head)
		       || TREE_CODE (head) == REAL_TYPE
		       || TREE_CODE (head) == FIXED_POINT_TYPE))
	    TB_SET_HEAD (TYPE_MAX_VALUE (head));
	  else
	    TB_WF;
	  break;

	case TB_MIN:
	  if (head && (INTEGRAL_TYPE_P (head)
		       || TREE_CODE (head) == REAL_TYPE
		       || TREE_CODE (head) == FIXED_POINT_TYPE))
	    TB_SET_HEAD (TYPE_MIN_VALUE (head));
	  else
	    TB_WF;
	  break;

	case TB_ELT:
	  if (head && TREE_CODE (head) == TREE_VEC)
	    {
	      /* This command takes another argument: the element number:
		 for example "elt 1".  */
	      TB_NIY;
	    }
	  else if (head && TREE_CODE (head) == VECTOR_CST)
	    {
	      /* This command takes another argument: the element number:
                 for example "elt 1".  */
              TB_NIY;
	    }
	  else
	    TB_WF;
	  break;

	case TB_VALUE:
	  if (head && TREE_CODE (head) == TREE_LIST)
	    TB_SET_HEAD (TREE_VALUE (head));
	  else
	    TB_WF;
	  break;

	case TB_PURPOSE:
	  if (head && TREE_CODE (head) == TREE_LIST)
	    TB_SET_HEAD (TREE_PURPOSE (head));
	  else
	    TB_WF;
	  break;

	case TB_IMAG:
	  if (head && TREE_CODE (head) == COMPLEX_CST)
	    TB_SET_HEAD (TREE_IMAGPART (head));
	  else
	    TB_WF;
	  break;

	case TB_REAL:
	  if (head && TREE_CODE (head) == COMPLEX_CST)
	    TB_SET_HEAD (TREE_REALPART (head));
	  else
	    TB_WF;
	  break;

	case TB_BLOCK:
	  if (head && TREE_CODE (head) == BIND_EXPR)
	    TB_SET_HEAD (TREE_OPERAND (head, 2));
	  else
	    TB_WF;
	  break;

	case TB_SUBBLOCKS:
	  if (head && TREE_CODE (head) == BLOCK)
	    TB_SET_HEAD (BLOCK_SUBBLOCKS (head));
	  else
	    TB_WF;
	  break;

	case TB_SUPERCONTEXT:
	  if (head && TREE_CODE (head) == BLOCK)
	    TB_SET_HEAD (BLOCK_SUPERCONTEXT (head));
	  else
	    TB_WF;
	  break;

	case TB_VARS:
	  if (head && TREE_CODE (head) == BLOCK)
	    TB_SET_HEAD (BLOCK_VARS (head));
	  else if (head && TREE_CODE (head) == BIND_EXPR)
	    TB_SET_HEAD (TREE_OPERAND (head, 0));
	  else
	    TB_WF;
	  break;

	case TB_REFERENCE_TO_THIS:
	  if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_REFERENCE_TO (head));
	  else
	    TB_WF;
	  break;

	case TB_POINTER_TO_THIS:
	  if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_POINTER_TO (head));
	  else
	    TB_WF;
	  break;

	case TB_BASETYPE:
	  if (head && TREE_CODE (head) == OFFSET_TYPE)
	    TB_SET_HEAD (TYPE_OFFSET_BASETYPE (head));
	  else
	    TB_WF;
	  break;

	case TB_ARG_TYPES:
	  if (head && (TREE_CODE (head) == FUNCTION_TYPE
		       || TREE_CODE (head) == METHOD_TYPE))
	    TB_SET_HEAD (TYPE_ARG_TYPES (head));
	  else
	    TB_WF;
	  break;

	case TB_METHOD_BASE_TYPE:
	  if (head && (TREE_CODE (head) == FUNCTION_TYPE
		       || TREE_CODE (head) == METHOD_TYPE)
	      && TYPE_METHOD_BASETYPE (head))
	    TB_SET_HEAD (TYPE_METHOD_BASETYPE (head));
	  else
	    TB_WF;
	  break;

	case TB_FIELDS:
	  if (head && (TREE_CODE (head) == RECORD_TYPE
		       || TREE_CODE (head) == UNION_TYPE
		       || TREE_CODE (head) == QUAL_UNION_TYPE))
	    TB_SET_HEAD (TYPE_FIELDS (head));
	  else
	    TB_WF;
	  break;

	case TB_DOMAIN:
	  if (head && TREE_CODE (head) == ARRAY_TYPE)
	    TB_SET_HEAD (TYPE_DOMAIN (head));
	  else
	    TB_WF;
	  break;

	case TB_VALUES:
	  if (head && TREE_CODE (head) == ENUMERAL_TYPE)
	    TB_SET_HEAD (TYPE_VALUES (head));
	  else
	    TB_WF;
	  break;

	case TB_ARG_TYPE:
	  if (head && TREE_CODE (head) == PARM_DECL)
	    TB_SET_HEAD (DECL_ARG_TYPE (head));
	  else
	    TB_WF;
	  break;

	case TB_INITIAL:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_INITIAL (head));
	  else
	    TB_WF;
	  break;

	case TB_RESULT:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_RESULT_FLD (head));
	  else
	    TB_WF;
	  break;

	case TB_ARGUMENTS:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_ARGUMENTS (head));
	  else
	    TB_WF;
	  break;

	case TB_ABSTRACT_ORIGIN:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_ABSTRACT_ORIGIN (head));
	  else if (head && TREE_CODE (head) == BLOCK)
	    TB_SET_HEAD (BLOCK_ABSTRACT_ORIGIN (head));
	  else
	    TB_WF;
	  break;

	case TB_ATTRIBUTES:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_ATTRIBUTES (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_ATTRIBUTES (head));
	  else
	    TB_WF;
	  break;

	case TB_CONTEXT:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_CONTEXT (head));
	  else if (head && TYPE_P (head)
		   && TYPE_CONTEXT (head))
	    TB_SET_HEAD (TYPE_CONTEXT (head));
	  else
	    TB_WF;
	  break;

	case TB_OFFSET:
	  if (head && TREE_CODE (head) == FIELD_DECL)
	    TB_SET_HEAD (DECL_FIELD_OFFSET (head));
	  else
	    TB_WF;
	  break;

	case TB_BIT_OFFSET:
	  if (head && TREE_CODE (head) == FIELD_DECL)
	    TB_SET_HEAD (DECL_FIELD_BIT_OFFSET (head));
	  else
	    TB_WF;
          break;

	case TB_UNIT_SIZE:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_SIZE_UNIT (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_SIZE_UNIT (head));
	  else
	    TB_WF;
	  break;

	case TB_SIZE:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_SIZE (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_SIZE (head));
	  else
	    TB_WF;
	  break;

	case TB_TYPE:
	  if (head && TREE_TYPE (head))
	    TB_SET_HEAD (TREE_TYPE (head));
	  else
	    TB_WF;
	  break;

	case TB_DECL_SAVED_TREE:
	  if (head && TREE_CODE (head) == FUNCTION_DECL
	      && DECL_SAVED_TREE (head))
	    TB_SET_HEAD (DECL_SAVED_TREE (head));
	  else
	    TB_WF;
	  break;

	case TB_BODY:
	  if (head && TREE_CODE (head) == BIND_EXPR)
	    TB_SET_HEAD (TREE_OPERAND (head, 1));
	  else
	    TB_WF;
	  break;

	case TB_CHILD_0:
	  if (head && EXPR_P (head) && TREE_OPERAND (head, 0))
	    TB_SET_HEAD (TREE_OPERAND (head, 0));
	  else
	    TB_WF;
	  break;

	case TB_CHILD_1:
          if (head && EXPR_P (head) && TREE_OPERAND (head, 1))
	    TB_SET_HEAD (TREE_OPERAND (head, 1));
	  else
	    TB_WF;
          break;

	case TB_CHILD_2:
          if (head && EXPR_P (head) && TREE_OPERAND (head, 2))
	    TB_SET_HEAD (TREE_OPERAND (head, 2));
	  else
	    TB_WF;
	  break;

	case TB_CHILD_3:
	  if (head && EXPR_P (head) && TREE_OPERAND (head, 3))
	    TB_SET_HEAD (TREE_OPERAND (head, 3));
	  else
	    TB_WF;
          break;

	case TB_PRINT:
	  if (head)
	    debug_tree (head);
	  else
	    TB_WF;
	  break;

	case TB_PRETTY_PRINT:
	  if (head)
	    {
	      print_generic_stmt (TB_OUT_FILE, head, 0);
	      fprintf (TB_OUT_FILE, "\n");
	    }
	  else
	    TB_WF;
	  break;

	case TB_SEARCH_NAME:

	  break;

	case TB_SEARCH_CODE:
	  {
	    enum tree_code code;
	    char *arg_text;

	    arg_text = strchr (input, ' ');
	    if (arg_text == NULL)
	      {
		fprintf (TB_OUT_FILE, "First argument is missing.  This isn't a valid search command.  \n");
		break;
	      }
	    code = TB_get_tree_code (arg_text + 1);

	    /* Search in the subtree a node with the given code.  */
	    {
	      tree res;

	      res = walk_tree (&head, find_node_with_code, &code, NULL);
	      if (res == NULL_TREE)
		{
		  fprintf (TB_OUT_FILE, "There's no node with this code (reachable via the walk_tree function from this node).\n");
		}
	      else
		{
		  fprintf (TB_OUT_FILE, "Achoo!  I got this node in the tree.\n");
		  TB_SET_HEAD (res);
		}
	    }
	    break;
	  }

#define TB_MOVE_HEAD(FCT) do {       \
  if (head)                          \
    {                                \
      tree t;                        \
      t = FCT (head);                \
      if (t)                         \
        TB_SET_HEAD (t);             \
      else                           \
	TB_WF;                       \
    }                                \
  else                               \
    TB_WF;                           \
} while (0)

	case TB_FIRST:
	  TB_MOVE_HEAD (TB_first_in_bind);
          break;

        case TB_LAST:
          TB_MOVE_HEAD (TB_last_in_bind);
          break;

	case TB_UP:
	  TB_MOVE_HEAD (TB_up_expr);
	  break;

	case TB_PREV:
	  TB_MOVE_HEAD (TB_prev_expr);
	  break;

	case TB_NEXT:
	  TB_MOVE_HEAD (TB_next_expr);
	  break;

	case TB_HPREV:
	  /* This command is a little bit special, since it deals with history
	     stack.  For this reason it should keep the "head = ..." statement
	     and not use TB_MOVE_HEAD.  */
	  if (head)
	    {
	      tree t;
	      t = TB_history_prev ();
	      if (t)
		{
		  head = t;
		  if (TB_verbose)
		    {
		      print_generic_expr (TB_OUT_FILE, head, 0);
		      fprintf (TB_OUT_FILE, "\n");
		    }
		}
	      else
		TB_WF;
	    }
	  else
	    TB_WF;
	  break;

	case TB_CHAIN:
	  /* Don't go further if it's the last node in this chain.  */
	  if (head && TREE_CODE (head) == BLOCK)
	    TB_SET_HEAD (BLOCK_CHAIN (head));
	  else if (head && TREE_CHAIN (head))
	    TB_SET_HEAD (TREE_CHAIN (head));
	  else
	    TB_WF;
	  break;

	case TB_FUN:
	  /* Go up to the current function declaration.  */
	  TB_SET_HEAD (current_function_decl);
	  fprintf (TB_OUT_FILE, "Current function declaration.\n");
	  break;

	case TB_HELP:
	  /* Display a help message.  */
	  {
	    int i;
	    fprintf (TB_OUT_FILE, "Possible commands are:\n\n");
	    for (i = 0; i < TB_UNUSED_COMMAND; i++)
	      {
		fprintf (TB_OUT_FILE, "%20s  -  %s\n", TB_COMMAND_TEXT (i), TB_COMMAND_HELP (i));
	      }
	  }
	  break;

	case TB_VERBOSE:
	  if (TB_verbose == 0)
	    {
	      TB_verbose = 1;
	      fprintf (TB_OUT_FILE, "Verbose on.\n");
	    }
	  else
	    {
	      TB_verbose = 0;
	      fprintf (TB_OUT_FILE, "Verbose off.\n");
	    }
	  break;

	case TB_EXIT:
	case TB_QUIT:
	  /* Just exit from this function.  */
	  goto ret;

	default:
	  TB_NIY;
	}
    }

 ret:;
  TB_up_ht.dispose ();
  return;
}


/* Search the first node in this BIND_EXPR.  */

static tree
TB_first_in_bind (tree node)
{
  tree t;

  if (node == NULL_TREE)
    return NULL_TREE;

  while ((t = TB_prev_expr (node)))
    node = t;

  return node;
}

/* Search the last node in this BIND_EXPR.  */

static tree
TB_last_in_bind (tree node)
{
  tree t;

  if (node == NULL_TREE)
    return NULL_TREE;

  while ((t = TB_next_expr (node)))
    node = t;

  return node;
}

/* Search the parent expression for this node.  */

static tree
TB_up_expr (tree node)
{
  tree res;
  if (node == NULL_TREE)
    return NULL_TREE;

  res = TB_up_ht.find (node);
  return res;
}

/* Search the previous expression in this BIND_EXPR.  */

static tree
TB_prev_expr (tree node)
{
  node = TB_current_chain_node (node);

  if (node == NULL_TREE)
    return NULL_TREE;

  node = TB_up_expr (node);
  if (node && TREE_CODE (node) == COMPOUND_EXPR)
    return node;
  else
    return NULL_TREE;
}

/* Search the next expression in this BIND_EXPR.  */

static tree
TB_next_expr (tree node)
{
  node = TB_current_chain_node (node);

  if (node == NULL_TREE)
    return NULL_TREE;

  node = TREE_OPERAND (node, 1);
  return node;
}

static tree
TB_current_chain_node (tree node)
{
  if (node == NULL_TREE)
    return NULL_TREE;

  if (TREE_CODE (node) == COMPOUND_EXPR)
    return node;

  node = TB_up_expr (node);
  if (node)
    {
      if (TREE_CODE (node) == COMPOUND_EXPR)
	return node;

      node = TB_up_expr (node);
      if (TREE_CODE (node) == COMPOUND_EXPR)
	return node;
    }

  return NULL_TREE;
}

/* For each node store in its children nodes that the current node is their
   parent.  This function is used by walk_tree.  */

static tree
store_child_info (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
		  void *data ATTRIBUTE_UNUSED)
{
  tree node;
  tree_node **slot;

  node = *tp;

  /* 'node' is the parent of 'TREE_OPERAND (node, *)'.  */
  if (EXPR_P (node))
    {
      int n = TREE_OPERAND_LENGTH (node);
      int i;
      for (i = 0; i < n; i++)
	{
	  tree op = TREE_OPERAND (node, i);
	  slot = TB_up_ht.find_slot (op, INSERT);
	  *slot = node;
	}
    }

  /* Never stop walk_tree.  */
  return NULL_TREE;
}

/* Update information about upper expressions in the hash table.  */

static void
TB_update_up (tree node)
{
  while (node)
    {
      walk_tree (&node, store_child_info, NULL, NULL);

      /* Walk function's body.  */
      if (TREE_CODE (node) == FUNCTION_DECL)
        if (DECL_SAVED_TREE (node))
          walk_tree (&DECL_SAVED_TREE (node), store_child_info, NULL, NULL);

      /* Walk rest of the chain.  */
      node = TREE_CHAIN (node);
    }
  fprintf (TB_OUT_FILE, "Up/prev expressions updated.\n");
}

/* Parse the input string for determining the command the user asked for.  */

static TB_CODE
TB_get_command (char *input)
{
  unsigned int mn, size_tok;
  int comp;
  char *space;

  space = strchr (input, ' ');
  if (space != NULL)
    size_tok = strlen (input) - strlen (space);
  else
    size_tok = strlen (input) - 1;

  for (mn = 0; mn < TB_UNUSED_COMMAND; mn++)
    {
      if (size_tok != TB_COMMAND_LEN (mn))
	continue;

      comp = memcmp (input, TB_COMMAND_TEXT (mn), TB_COMMAND_LEN (mn));
      if (comp == 0)
	/* Here we just determined the command.  If this command takes
	   an argument, then the argument is determined later.  */
	return TB_COMMAND_CODE (mn);
    }

  /* Not a valid command.  */
  return TB_UNUSED_COMMAND;
}

/* Parse the input string for determining the tree code.  */

static enum tree_code
TB_get_tree_code (char *input)
{
  unsigned int mn, size_tok;
  int comp;
  char *space;

  space = strchr (input, ' ');
  if (space != NULL)
    size_tok = strlen (input) - strlen (space);
  else
    size_tok = strlen (input) - 1;

  for (mn = 0; mn < LAST_AND_UNUSED_TREE_CODE; mn++)
    {
      if (size_tok != TB_TREE_CODE_LEN (mn))
	continue;

      comp = memcmp (input, TB_TREE_CODE_TEXT (mn), TB_TREE_CODE_LEN (mn));
      if (comp == 0)
	{
	  fprintf (TB_OUT_FILE, "%s\n", TB_TREE_CODE_TEXT (mn));
	  return TB_TREE_CODE (mn);
	}
    }

  /* This isn't a valid code.  */
  return LAST_AND_UNUSED_TREE_CODE;
}

/* Find a node with a given code.  This function is used as an argument to
   walk_tree.  */

static tree
find_node_with_code (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
		     void *data)
{
  enum tree_code *code;
  code = (enum tree_code *) data;
  if (*code == TREE_CODE (*tp))
    return *tp;

  return NULL_TREE;
}

/* Returns a pointer to the last visited node.  */

static tree
TB_history_prev (void)
{
  if (!vec_safe_is_empty (TB_history_stack))
    {
      tree last = TB_history_stack->last ();
      TB_history_stack->pop ();
      return last;
    }
  return NULL_TREE;
}

/* Read up to (and including) a '\n' from STREAM into *LINEPTR
   (and null-terminate it). *LINEPTR is a pointer returned from malloc
   (or NULL), pointing to *N characters of space.  It is realloc'd as
   necessary.  Returns the number of characters read (not including the
   null terminator), or -1 on error or EOF.
   This function comes from sed (and is supposed to be a portable version
   of getline).  */

static long
TB_getline (char **lineptr, long *n, FILE *stream)
{
  char *line, *p;
  long size, copy;

  if (lineptr == NULL || n == NULL)
    {
      errno = EINVAL;
      return -1;
    }

  if (ferror (stream))
    return -1;

  /* Make sure we have a line buffer to start with.  */
  if (*lineptr == NULL || *n < 2) /* !seen and no buf yet need 2 chars.  */
    {
#ifndef MAX_CANON
#define MAX_CANON       256
#endif
      line = (char *) xrealloc (*lineptr, MAX_CANON);
      if (line == NULL)
        return -1;
      *lineptr = line;
      *n = MAX_CANON;
    }

  line = *lineptr;
  size = *n;

  copy = size;
  p = line;

  while (1)
    {
      long len;

      while (--copy > 0)
        {
          register int c = getc (stream);
          if (c == EOF)
            goto lose;
          else if ((*p++ = c) == '\n')
            goto win;
        }

      /* Need to enlarge the line buffer.  */
      len = p - line;
      size *= 2;
      line = (char *) xrealloc (line, size);
      if (line == NULL)
        goto lose;
      *lineptr = line;
      *n = size;
      p = line + len;
      copy = size - len;
    }

 lose:
  if (p == *lineptr)
    return -1;

  /* Return a partial line since we got an error in the middle.  */
 win:
#if defined(WIN32) || defined(_WIN32) || defined(__CYGWIN__) || defined(MSDOS)
  if (p - 2 >= *lineptr && p[-2] == '\r')
    p[-2] = p[-1], --p;
#endif
  *p = '\0';
  return p - *lineptr;
}