xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/mi/mi-cmd-var.c (revision 3f351f34c6d827cf017cdcff3543f6ec0c88b420)
1 /* MI Command Set - varobj commands.
2    Copyright (C) 2000-2020 Free Software Foundation, Inc.
3 
4    Contributed by Cygnus Solutions (a Red Hat company).
5 
6    This file is part of GDB.
7 
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 3 of the License, or
11    (at your option) any later version.
12 
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17 
18    You should have received a copy of the GNU General Public License
19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
20 
21 #include "defs.h"
22 #include "mi-cmds.h"
23 #include "mi-main.h"
24 #include "ui-out.h"
25 #include "mi-out.h"
26 #include "varobj.h"
27 #include "language.h"
28 #include "value.h"
29 #include <ctype.h>
30 #include "mi-getopt.h"
31 #include "gdbthread.h"
32 #include "mi-parse.h"
33 #include "gdbsupport/gdb_optional.h"
34 #include "inferior.h"
35 
36 static void varobj_update_one (struct varobj *var,
37 			       enum print_values print_values,
38 			       bool is_explicit);
39 
40 static int mi_print_value_p (struct varobj *var,
41 			     enum print_values print_values);
42 
43 /* Print variable object VAR.  The PRINT_VALUES parameter controls
44    if the value should be printed.  The PRINT_EXPRESSION parameter
45    controls if the expression should be printed.  */
46 
47 static void
48 print_varobj (struct varobj *var, enum print_values print_values,
49 	      int print_expression)
50 {
51   struct ui_out *uiout = current_uiout;
52   int thread_id;
53 
54   uiout->field_string ("name", varobj_get_objname (var));
55   if (print_expression)
56     {
57       std::string exp = varobj_get_expression (var);
58 
59       uiout->field_string ("exp", exp.c_str ());
60     }
61   uiout->field_signed ("numchild", varobj_get_num_children (var));
62 
63   if (mi_print_value_p (var, print_values))
64     {
65       std::string val = varobj_get_value (var);
66 
67       uiout->field_string ("value", val.c_str ());
68     }
69 
70   std::string type = varobj_get_type (var);
71   if (!type.empty ())
72     uiout->field_string ("type", type.c_str ());
73 
74   thread_id = varobj_get_thread_id (var);
75   if (thread_id > 0)
76     uiout->field_signed ("thread-id", thread_id);
77 
78   if (varobj_get_frozen (var))
79     uiout->field_signed ("frozen", 1);
80 
81   gdb::unique_xmalloc_ptr<char> display_hint = varobj_get_display_hint (var);
82   if (display_hint)
83     uiout->field_string ("displayhint", display_hint.get ());
84 
85   if (varobj_is_dynamic_p (var))
86     uiout->field_signed ("dynamic", 1);
87 }
88 
89 /* VAROBJ operations */
90 
91 void
92 mi_cmd_var_create (const char *command, char **argv, int argc)
93 {
94   struct ui_out *uiout = current_uiout;
95   CORE_ADDR frameaddr = 0;
96   struct varobj *var;
97   char *frame;
98   char *expr;
99   enum varobj_type var_type;
100 
101   if (argc != 3)
102     error (_("-var-create: Usage: NAME FRAME EXPRESSION."));
103 
104   frame = argv[1];
105   expr = argv[2];
106 
107   const char *name = argv[0];
108   std::string gen_name;
109   if (strcmp (name, "-") == 0)
110     {
111       gen_name = varobj_gen_name ();
112       name = gen_name.c_str ();
113     }
114   else if (!isalpha (name[0]))
115     error (_("-var-create: name of object must begin with a letter"));
116 
117   if (strcmp (frame, "*") == 0)
118     var_type = USE_CURRENT_FRAME;
119   else if (strcmp (frame, "@") == 0)
120     var_type = USE_SELECTED_FRAME;
121   else
122     {
123       var_type = USE_SPECIFIED_FRAME;
124       frameaddr = string_to_core_addr (frame);
125     }
126 
127   if (varobjdebug)
128     fprintf_unfiltered (gdb_stdlog,
129 			"Name=\"%s\", Frame=\"%s\" (%s), Expression=\"%s\"\n",
130 			name, frame, hex_string (frameaddr), expr);
131 
132   var = varobj_create (name, expr, frameaddr, var_type);
133 
134   if (var == NULL)
135     error (_("-var-create: unable to create variable object"));
136 
137   print_varobj (var, PRINT_ALL_VALUES, 0 /* don't print expression */);
138 
139   uiout->field_signed ("has_more", varobj_has_more (var, 0));
140 }
141 
142 void
143 mi_cmd_var_delete (const char *command, char **argv, int argc)
144 {
145   char *name;
146   struct varobj *var;
147   int numdel;
148   int children_only_p = 0;
149   struct ui_out *uiout = current_uiout;
150 
151   if (argc < 1 || argc > 2)
152     error (_("-var-delete: Usage: [-c] EXPRESSION."));
153 
154   name = argv[0];
155 
156   /* If we have one single argument it cannot be '-c' or any string
157      starting with '-'.  */
158   if (argc == 1)
159     {
160       if (strcmp (name, "-c") == 0)
161 	error (_("-var-delete: Missing required "
162 		 "argument after '-c': variable object name"));
163       if (*name == '-')
164 	error (_("-var-delete: Illegal variable object name"));
165     }
166 
167   /* If we have 2 arguments they must be '-c' followed by a string
168      which would be the variable name.  */
169   if (argc == 2)
170     {
171       if (strcmp (name, "-c") != 0)
172 	error (_("-var-delete: Invalid option."));
173       children_only_p = 1;
174       name = argv[1];
175     }
176 
177   /* If we didn't error out, now NAME contains the name of the
178      variable.  */
179 
180   var = varobj_get_handle (name);
181 
182   numdel = varobj_delete (var, children_only_p);
183 
184   uiout->field_signed ("ndeleted", numdel);
185 }
186 
187 /* Parse a string argument into a format value.  */
188 
189 static enum varobj_display_formats
190 mi_parse_format (const char *arg)
191 {
192   if (arg != NULL)
193     {
194       int len;
195 
196       len = strlen (arg);
197 
198       if (strncmp (arg, "natural", len) == 0)
199 	return FORMAT_NATURAL;
200       else if (strncmp (arg, "binary", len) == 0)
201 	return FORMAT_BINARY;
202       else if (strncmp (arg, "decimal", len) == 0)
203 	return FORMAT_DECIMAL;
204       else if (strncmp (arg, "hexadecimal", len) == 0)
205 	return FORMAT_HEXADECIMAL;
206       else if (strncmp (arg, "octal", len) == 0)
207 	return FORMAT_OCTAL;
208       else if (strncmp (arg, "zero-hexadecimal", len) == 0)
209 	return FORMAT_ZHEXADECIMAL;
210     }
211 
212   error (_("Must specify the format as: \"natural\", "
213 	   "\"binary\", \"decimal\", \"hexadecimal\", \"octal\" or \"zero-hexadecimal\""));
214 }
215 
216 void
217 mi_cmd_var_set_format (const char *command, char **argv, int argc)
218 {
219   enum varobj_display_formats format;
220   struct varobj *var;
221   struct ui_out *uiout = current_uiout;
222 
223   if (argc != 2)
224     error (_("-var-set-format: Usage: NAME FORMAT."));
225 
226   /* Get varobj handle, if a valid var obj name was specified.  */
227   var = varobj_get_handle (argv[0]);
228 
229   format = mi_parse_format (argv[1]);
230 
231   /* Set the format of VAR to the given format.  */
232   varobj_set_display_format (var, format);
233 
234   /* Report the new current format.  */
235   uiout->field_string ("format", varobj_format_string[(int) format]);
236 
237   /* Report the value in the new format.  */
238   std::string val = varobj_get_value (var);
239   uiout->field_string ("value", val.c_str ());
240 }
241 
242 void
243 mi_cmd_var_set_visualizer (const char *command, char **argv, int argc)
244 {
245   struct varobj *var;
246 
247   if (argc != 2)
248     error (_("Usage: NAME VISUALIZER_FUNCTION."));
249 
250   var = varobj_get_handle (argv[0]);
251 
252   if (var == NULL)
253     error (_("Variable object not found"));
254 
255   varobj_set_visualizer (var, argv[1]);
256 }
257 
258 void
259 mi_cmd_var_set_frozen (const char *command, char **argv, int argc)
260 {
261   struct varobj *var;
262   bool frozen;
263 
264   if (argc != 2)
265     error (_("-var-set-format: Usage: NAME FROZEN_FLAG."));
266 
267   var = varobj_get_handle (argv[0]);
268 
269   if (strcmp (argv[1], "0") == 0)
270     frozen = false;
271   else if (strcmp (argv[1], "1") == 0)
272     frozen = true;
273   else
274     error (_("Invalid flag value"));
275 
276   varobj_set_frozen (var, frozen);
277 
278   /* We don't automatically return the new value, or what varobjs got
279      new values during unfreezing.  If this information is required,
280      client should call -var-update explicitly.  */
281 }
282 
283 void
284 mi_cmd_var_show_format (const char *command, char **argv, int argc)
285 {
286   struct ui_out *uiout = current_uiout;
287   enum varobj_display_formats format;
288   struct varobj *var;
289 
290   if (argc != 1)
291     error (_("-var-show-format: Usage: NAME."));
292 
293   /* Get varobj handle, if a valid var obj name was specified.  */
294   var = varobj_get_handle (argv[0]);
295 
296   format = varobj_get_display_format (var);
297 
298   /* Report the current format.  */
299   uiout->field_string ("format", varobj_format_string[(int) format]);
300 }
301 
302 void
303 mi_cmd_var_info_num_children (const char *command, char **argv, int argc)
304 {
305   struct ui_out *uiout = current_uiout;
306   struct varobj *var;
307 
308   if (argc != 1)
309     error (_("-var-info-num-children: Usage: NAME."));
310 
311   /* Get varobj handle, if a valid var obj name was specified.  */
312   var = varobj_get_handle (argv[0]);
313 
314   uiout->field_signed ("numchild", varobj_get_num_children (var));
315 }
316 
317 /* Return 1 if given the argument PRINT_VALUES we should display
318    the varobj VAR.  */
319 
320 static int
321 mi_print_value_p (struct varobj *var, enum print_values print_values)
322 {
323   struct type *type;
324 
325   if (print_values == PRINT_NO_VALUES)
326     return 0;
327 
328   if (print_values == PRINT_ALL_VALUES)
329     return 1;
330 
331   if (varobj_is_dynamic_p (var))
332     return 1;
333 
334   type = varobj_get_gdb_type (var);
335   if (type == NULL)
336     return 1;
337   else
338     {
339       type = check_typedef (type);
340 
341       /* For PRINT_SIMPLE_VALUES, only print the value if it has a type
342 	 and that type is not a compound type.  */
343       return (type->code () != TYPE_CODE_ARRAY
344 	      && type->code () != TYPE_CODE_STRUCT
345 	      && type->code () != TYPE_CODE_UNION);
346     }
347 }
348 
349 void
350 mi_cmd_var_list_children (const char *command, char **argv, int argc)
351 {
352   struct ui_out *uiout = current_uiout;
353   struct varobj *var;
354   enum print_values print_values;
355   int from, to;
356 
357   if (argc < 1 || argc > 4)
358     error (_("-var-list-children: Usage: "
359 	     "[PRINT_VALUES] NAME [FROM TO]"));
360 
361   /* Get varobj handle, if a valid var obj name was specified.  */
362   if (argc == 1 || argc == 3)
363     var = varobj_get_handle (argv[0]);
364   else
365     var = varobj_get_handle (argv[1]);
366 
367   if (argc > 2)
368     {
369       from = atoi (argv[argc - 2]);
370       to = atoi (argv[argc - 1]);
371     }
372   else
373     {
374       from = -1;
375       to = -1;
376     }
377 
378   const std::vector<varobj *> &children
379     = varobj_list_children (var, &from, &to);
380 
381   uiout->field_signed ("numchild", to - from);
382   if (argc == 2 || argc == 4)
383     print_values = mi_parse_print_values (argv[0]);
384   else
385     print_values = PRINT_NO_VALUES;
386 
387   gdb::unique_xmalloc_ptr<char> display_hint = varobj_get_display_hint (var);
388   if (display_hint)
389     uiout->field_string ("displayhint", display_hint.get ());
390 
391   if (from < to)
392     {
393       /* For historical reasons this might emit a list or a tuple, so
394 	 we construct one or the other.  */
395       gdb::optional<ui_out_emit_tuple> tuple_emitter;
396       gdb::optional<ui_out_emit_list> list_emitter;
397 
398       if (mi_version (uiout) == 1)
399 	tuple_emitter.emplace (uiout, "children");
400       else
401 	list_emitter.emplace (uiout, "children");
402       for (int ix = from; ix < to && ix < children.size (); ix++)
403 	{
404 	  ui_out_emit_tuple child_emitter (uiout, "child");
405 
406 	  print_varobj (children[ix], print_values, 1 /* print expression */);
407 	}
408     }
409 
410   uiout->field_signed ("has_more", varobj_has_more (var, to));
411 }
412 
413 void
414 mi_cmd_var_info_type (const char *command, char **argv, int argc)
415 {
416   struct ui_out *uiout = current_uiout;
417   struct varobj *var;
418 
419   if (argc != 1)
420     error (_("-var-info-type: Usage: NAME."));
421 
422   /* Get varobj handle, if a valid var obj name was specified.  */
423   var = varobj_get_handle (argv[0]);
424 
425   std::string type_name = varobj_get_type (var);
426   uiout->field_string ("type", type_name.c_str ());
427 }
428 
429 void
430 mi_cmd_var_info_path_expression (const char *command, char **argv, int argc)
431 {
432   struct ui_out *uiout = current_uiout;
433   struct varobj *var;
434 
435   if (argc != 1)
436     error (_("Usage: NAME."));
437 
438   /* Get varobj handle, if a valid var obj name was specified.  */
439   var = varobj_get_handle (argv[0]);
440 
441   const char *path_expr = varobj_get_path_expr (var);
442 
443   uiout->field_string ("path_expr", path_expr);
444 }
445 
446 void
447 mi_cmd_var_info_expression (const char *command, char **argv, int argc)
448 {
449   struct ui_out *uiout = current_uiout;
450   const struct language_defn *lang;
451   struct varobj *var;
452 
453   if (argc != 1)
454     error (_("-var-info-expression: Usage: NAME."));
455 
456   /* Get varobj handle, if a valid var obj name was specified.  */
457   var = varobj_get_handle (argv[0]);
458 
459   lang = varobj_get_language (var);
460 
461   uiout->field_string ("lang", lang->la_natural_name);
462 
463   std::string exp = varobj_get_expression (var);
464   uiout->field_string ("exp", exp.c_str ());
465 }
466 
467 void
468 mi_cmd_var_show_attributes (const char *command, char **argv, int argc)
469 {
470   struct ui_out *uiout = current_uiout;
471   int attr;
472   const char *attstr;
473   struct varobj *var;
474 
475   if (argc != 1)
476     error (_("-var-show-attributes: Usage: NAME."));
477 
478   /* Get varobj handle, if a valid var obj name was specified */
479   var = varobj_get_handle (argv[0]);
480 
481   attr = varobj_get_attributes (var);
482   /* FIXME: define masks for attributes */
483   if (attr & 0x00000001)
484     attstr = "editable";
485   else
486     attstr = "noneditable";
487 
488   uiout->field_string ("attr", attstr);
489 }
490 
491 void
492 mi_cmd_var_evaluate_expression (const char *command, char **argv, int argc)
493 {
494   struct ui_out *uiout = current_uiout;
495   struct varobj *var;
496 
497   enum varobj_display_formats format;
498   int formatFound;
499   int oind;
500   char *oarg;
501 
502   enum opt
503   {
504     OP_FORMAT
505   };
506   static const struct mi_opt opts[] =
507     {
508       {"f", OP_FORMAT, 1},
509       { 0, 0, 0 }
510     };
511 
512   /* Parse arguments.  */
513   format = FORMAT_NATURAL;
514   formatFound = 0;
515   oind = 0;
516   while (1)
517     {
518       int opt = mi_getopt ("-var-evaluate-expression", argc, argv,
519 			   opts, &oind, &oarg);
520 
521       if (opt < 0)
522 	break;
523       switch ((enum opt) opt)
524 	{
525 	case OP_FORMAT:
526 	  if (formatFound)
527 	    error (_("Cannot specify format more than once"));
528 
529 	  format = mi_parse_format (oarg);
530 	  formatFound = 1;
531 	  break;
532 	}
533     }
534 
535   if (oind >= argc)
536     error (_("Usage: [-f FORMAT] NAME"));
537 
538   if (oind < argc - 1)
539     error (_("Garbage at end of command"));
540 
541   /* Get varobj handle, if a valid var obj name was specified.  */
542   var = varobj_get_handle (argv[oind]);
543 
544   if (formatFound)
545     {
546       std::string val = varobj_get_formatted_value (var, format);
547 
548       uiout->field_string ("value", val.c_str ());
549     }
550   else
551     {
552       std::string val = varobj_get_value (var);
553 
554       uiout->field_string ("value", val.c_str ());
555     }
556 }
557 
558 void
559 mi_cmd_var_assign (const char *command, char **argv, int argc)
560 {
561   struct ui_out *uiout = current_uiout;
562   struct varobj *var;
563 
564   if (argc != 2)
565     error (_("-var-assign: Usage: NAME EXPRESSION."));
566 
567   /* Get varobj handle, if a valid var obj name was specified.  */
568   var = varobj_get_handle (argv[0]);
569 
570   if (!varobj_editable_p (var))
571     error (_("-var-assign: Variable object is not editable"));
572 
573   const char *expression = argv[1];
574 
575   /* MI command '-var-assign' may write memory, so suppress memory
576      changed notification if it does.  */
577   scoped_restore save_suppress
578     = make_scoped_restore (&mi_suppress_notification.memory, 1);
579 
580   if (!varobj_set_value (var, expression))
581     error (_("-var-assign: Could not assign "
582 	     "expression to variable object"));
583 
584   std::string val = varobj_get_value (var);
585   uiout->field_string ("value", val.c_str ());
586 }
587 
588 /* Type used for parameters passing to mi_cmd_var_update_iter.  */
589 
590 struct mi_cmd_var_update
591   {
592     int only_floating;
593     enum print_values print_values;
594   };
595 
596 /* Helper for mi_cmd_var_update - update each VAR.  */
597 
598 static void
599 mi_cmd_var_update_iter (struct varobj *var, void *data_pointer)
600 {
601   struct mi_cmd_var_update *data = (struct mi_cmd_var_update *) data_pointer;
602   bool thread_stopped;
603 
604   int thread_id = varobj_get_thread_id (var);
605 
606   if (thread_id == -1)
607     {
608       thread_stopped = (inferior_ptid == null_ptid
609 			|| inferior_thread ()->state == THREAD_STOPPED);
610     }
611   else
612     {
613       thread_info *tp = find_thread_global_id (thread_id);
614 
615       thread_stopped = (tp == NULL
616 			|| tp->state == THREAD_STOPPED);
617     }
618 
619   if (thread_stopped
620       && (!data->only_floating || varobj_floating_p (var)))
621     varobj_update_one (var, data->print_values, false /* implicit */);
622 }
623 
624 void
625 mi_cmd_var_update (const char *command, char **argv, int argc)
626 {
627   struct ui_out *uiout = current_uiout;
628   char *name;
629   enum print_values print_values;
630 
631   if (argc != 1 && argc != 2)
632     error (_("-var-update: Usage: [PRINT_VALUES] NAME."));
633 
634   if (argc == 1)
635     name = argv[0];
636   else
637     name = argv[1];
638 
639   if (argc == 2)
640     print_values = mi_parse_print_values (argv[0]);
641   else
642     print_values = PRINT_NO_VALUES;
643 
644   /* For historical reasons this might emit a list or a tuple, so we
645      construct one or the other.  */
646   gdb::optional<ui_out_emit_tuple> tuple_emitter;
647   gdb::optional<ui_out_emit_list> list_emitter;
648 
649   if (mi_version (uiout) <= 1)
650     tuple_emitter.emplace (uiout, "changelist");
651   else
652     list_emitter.emplace (uiout, "changelist");
653 
654   /* Check if the parameter is a "*", which means that we want to
655      update all variables.  */
656 
657   if ((*name == '*' || *name == '@') && (*(name + 1) == '\0'))
658     {
659       struct mi_cmd_var_update data;
660 
661       data.only_floating = (*name == '@');
662       data.print_values = print_values;
663 
664       /* varobj_update_one automatically updates all the children of
665 	 VAROBJ.  Therefore update each VAROBJ only once by iterating
666 	 only the root VAROBJs.  */
667 
668       all_root_varobjs (mi_cmd_var_update_iter, &data);
669     }
670   else
671     {
672       /* Get varobj handle, if a valid var obj name was specified.  */
673       struct varobj *var = varobj_get_handle (name);
674 
675       varobj_update_one (var, print_values, true /* explicit */);
676     }
677 }
678 
679 /* Helper for mi_cmd_var_update().  */
680 
681 static void
682 varobj_update_one (struct varobj *var, enum print_values print_values,
683 		   bool is_explicit)
684 {
685   struct ui_out *uiout = current_uiout;
686 
687   std::vector<varobj_update_result> changes = varobj_update (&var, is_explicit);
688 
689   for (const varobj_update_result &r : changes)
690     {
691       int from, to;
692 
693       gdb::optional<ui_out_emit_tuple> tuple_emitter;
694       if (mi_version (uiout) > 1)
695 	tuple_emitter.emplace (uiout, nullptr);
696       uiout->field_string ("name", varobj_get_objname (r.varobj));
697 
698       switch (r.status)
699 	{
700 	case VAROBJ_IN_SCOPE:
701 	  if (mi_print_value_p (r.varobj, print_values))
702 	    {
703 	      std::string val = varobj_get_value (r.varobj);
704 
705 	      uiout->field_string ("value", val.c_str ());
706 	    }
707 	  uiout->field_string ("in_scope", "true");
708 	  break;
709         case VAROBJ_NOT_IN_SCOPE:
710           uiout->field_string ("in_scope", "false");
711 	  break;
712         case VAROBJ_INVALID:
713           uiout->field_string ("in_scope", "invalid");
714  	  break;
715 	}
716 
717       if (r.status != VAROBJ_INVALID)
718 	{
719 	  if (r.type_changed)
720 	    uiout->field_string ("type_changed", "true");
721 	  else
722 	    uiout->field_string ("type_changed", "false");
723 	}
724 
725       if (r.type_changed)
726 	{
727 	  std::string type_name = varobj_get_type (r.varobj);
728 
729 	  uiout->field_string ("new_type", type_name.c_str ());
730 	}
731 
732       if (r.type_changed || r.children_changed)
733 	uiout->field_signed ("new_num_children",
734 			     varobj_get_num_children (r.varobj));
735 
736       gdb::unique_xmalloc_ptr<char> display_hint
737 	= varobj_get_display_hint (r.varobj);
738       if (display_hint)
739 	uiout->field_string ("displayhint", display_hint.get ());
740 
741       if (varobj_is_dynamic_p (r.varobj))
742 	uiout->field_signed ("dynamic", 1);
743 
744       varobj_get_child_range (r.varobj, &from, &to);
745       uiout->field_signed ("has_more", varobj_has_more (r.varobj, to));
746 
747       if (!r.newobj.empty ())
748 	{
749 	  ui_out_emit_list list_emitter (uiout, "new_children");
750 
751 	  for (varobj *child : r.newobj)
752 	    {
753 	      ui_out_emit_tuple inner_tuple_emitter (uiout, NULL);
754 	      print_varobj (child, print_values, 1 /* print_expression */);
755 	    }
756 	}
757     }
758 }
759 
760 void
761 mi_cmd_enable_pretty_printing (const char *command, char **argv, int argc)
762 {
763   if (argc != 0)
764     error (_("-enable-pretty-printing: no arguments allowed"));
765 
766   varobj_enable_pretty_printing ();
767 }
768 
769 void
770 mi_cmd_var_set_update_range (const char *command, char **argv, int argc)
771 {
772   struct varobj *var;
773   int from, to;
774 
775   if (argc != 3)
776     error (_("-var-set-update-range: Usage: VAROBJ FROM TO"));
777 
778   var = varobj_get_handle (argv[0]);
779   from = atoi (argv[1]);
780   to = atoi (argv[2]);
781 
782   varobj_set_child_range (var, from, to);
783 }
784