1 /* Copyright (C) 1992-2017 Free Software Foundation, Inc.
3 This file is part of GDB.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "gdbthread.h"
26 #include "progspace.h"
29 /* The name of the array in the GNAT runtime where the Ada Task Control
30 Block of each task is stored. */
31 #define KNOWN_TASKS_NAME "system__tasking__debug__known_tasks"
33 /* The maximum number of tasks known to the Ada runtime. */
34 static const int MAX_NUMBER_OF_KNOWN_TASKS
= 1000;
36 /* The name of the variable in the GNAT runtime where the head of a task
37 chain is saved. This is an alternate mechanism to find the list of known
39 #define KNOWN_TASKS_LIST "system__tasking__debug__first_task"
51 Master_Completion_Sleep
,
53 Interrupt_Server_Idle_Sleep
,
54 Interrupt_Server_Blocked_Interrupt_Sleep
,
58 Interrupt_Server_Blocked_On_Event_Flag
,
63 /* A short description corresponding to each possible task state. */
64 static const char *task_states
[] = {
68 N_("Child Activation Wait"),
69 N_("Accept or Select Term"),
70 N_("Waiting on entry call"),
71 N_("Async Select Wait"),
73 N_("Child Termination Wait"),
74 N_("Wait Child in Term Alt"),
79 N_("Asynchronous Hold"),
85 /* A longer description corresponding to each possible task state. */
86 static const char *long_task_states
[] = {
90 N_("Waiting for child activation"),
91 N_("Blocked in accept or select with terminate"),
92 N_("Waiting on entry call"),
93 N_("Asynchronous Selective Wait"),
95 N_("Waiting for children termination"),
96 N_("Waiting for children in terminate alternative"),
101 N_("Asynchronous Hold"),
104 N_("Blocked in selective wait statement")
107 /* The index of certain important fields in the Ada Task Control Block
108 record and sub-records. */
112 /* Fields in record Ada_Task_Control_Block. */
115 int atc_nesting_level
;
117 /* Fields in record Common_ATCB. */
122 int image_len
; /* This field may be missing. */
128 /* Fields in Task_Primitives.Private_Data. */
130 int ll_lwp
; /* This field may be missing. */
132 /* Fields in Common_ATCB.Call.all. */
136 /* This module's per-program-space data. */
138 struct ada_tasks_pspace_data
140 /* Nonzero if the data has been initialized. If set to zero,
141 it means that the data has either not been initialized, or
142 has potentially become stale. */
145 /* The ATCB record type. */
146 struct type
*atcb_type
;
148 /* The ATCB "Common" component type. */
149 struct type
*atcb_common_type
;
151 /* The type of the "ll" field, from the atcb_common_type. */
152 struct type
*atcb_ll_type
;
154 /* The type of the "call" field, from the atcb_common_type. */
155 struct type
*atcb_call_type
;
157 /* The index of various fields in the ATCB record and sub-records. */
158 struct atcb_fieldnos atcb_fieldno
;
161 /* Key to our per-program-space data. */
162 static const struct program_space_data
*ada_tasks_pspace_data_handle
;
164 typedef struct ada_task_info ada_task_info_s
;
165 DEF_VEC_O(ada_task_info_s
);
167 /* The kind of data structure used by the runtime to store the list
170 enum ada_known_tasks_kind
172 /* Use this value when we haven't determined which kind of structure
173 is being used, or when we need to recompute it.
175 We set the value of this enumerate to zero on purpose: This allows
176 us to use this enumerate in a structure where setting all fields
177 to zero will result in this kind being set to unknown. */
178 ADA_TASKS_UNKNOWN
= 0,
180 /* This value means that we did not find any task list. Unless
181 there is a bug somewhere, this means that the inferior does not
185 /* This value means that the task list is stored as an array.
186 This is the usual method, as it causes very little overhead.
187 But this method is not always used, as it does use a certain
188 amount of memory, which might be scarse in certain environments. */
191 /* This value means that the task list is stored as a linked list.
192 This has more runtime overhead than the array approach, but
193 also require less memory when the number of tasks is small. */
197 /* This module's per-inferior data. */
199 struct ada_tasks_inferior_data
201 /* The type of data structure used by the runtime to store
202 the list of Ada tasks. The value of this field influences
203 the interpretation of the known_tasks_addr field below:
204 - ADA_TASKS_UNKNOWN: The value of known_tasks_addr hasn't
206 - ADA_TASKS_NOT_FOUND: The program probably does not use tasking
207 and the known_tasks_addr is irrelevant;
208 - ADA_TASKS_ARRAY: The known_tasks is an array;
209 - ADA_TASKS_LIST: The known_tasks is a list. */
210 enum ada_known_tasks_kind known_tasks_kind
;
212 /* The address of the known_tasks structure. This is where
213 the runtime stores the information for all Ada tasks.
214 The interpretation of this field depends on KNOWN_TASKS_KIND
216 CORE_ADDR known_tasks_addr
;
218 /* Type of elements of the known task. Usually a pointer. */
219 struct type
*known_tasks_element
;
221 /* Number of elements in the known tasks array. */
222 unsigned int known_tasks_length
;
224 /* When nonzero, this flag indicates that the task_list field
225 below is up to date. When set to zero, the list has either
226 not been initialized, or has potentially become stale. */
227 int task_list_valid_p
;
229 /* The list of Ada tasks.
231 Note: To each task we associate a number that the user can use to
232 reference it - this number is printed beside each task in the tasks
233 info listing displayed by "info tasks". This number is equal to
234 its index in the vector + 1. Reciprocally, to compute the index
235 of a task in the vector, we need to substract 1 from its number. */
236 VEC(ada_task_info_s
) *task_list
;
239 /* Key to our per-inferior data. */
240 static const struct inferior_data
*ada_tasks_inferior_data_handle
;
242 /* Return the ada-tasks module's data for the given program space (PSPACE).
243 If none is found, add a zero'ed one now.
245 This function always returns a valid object. */
247 static struct ada_tasks_pspace_data
*
248 get_ada_tasks_pspace_data (struct program_space
*pspace
)
250 struct ada_tasks_pspace_data
*data
;
252 data
= ((struct ada_tasks_pspace_data
*)
253 program_space_data (pspace
, ada_tasks_pspace_data_handle
));
256 data
= XCNEW (struct ada_tasks_pspace_data
);
257 set_program_space_data (pspace
, ada_tasks_pspace_data_handle
, data
);
263 /* Return the ada-tasks module's data for the given inferior (INF).
264 If none is found, add a zero'ed one now.
266 This function always returns a valid object.
268 Note that we could use an observer of the inferior-created event
269 to make sure that the ada-tasks per-inferior data always exists.
270 But we prefered this approach, as it avoids this entirely as long
271 as the user does not use any of the tasking features. This is
272 quite possible, particularly in the case where the inferior does
275 static struct ada_tasks_inferior_data
*
276 get_ada_tasks_inferior_data (struct inferior
*inf
)
278 struct ada_tasks_inferior_data
*data
;
280 data
= ((struct ada_tasks_inferior_data
*)
281 inferior_data (inf
, ada_tasks_inferior_data_handle
));
284 data
= XCNEW (struct ada_tasks_inferior_data
);
285 set_inferior_data (inf
, ada_tasks_inferior_data_handle
, data
);
291 /* Return the task number of the task whose ptid is PTID, or zero
292 if the task could not be found. */
295 ada_get_task_number (ptid_t ptid
)
298 struct inferior
*inf
= find_inferior_ptid (ptid
);
299 struct ada_tasks_inferior_data
*data
;
301 gdb_assert (inf
!= NULL
);
302 data
= get_ada_tasks_inferior_data (inf
);
304 for (i
= 0; i
< VEC_length (ada_task_info_s
, data
->task_list
); i
++)
305 if (ptid_equal (VEC_index (ada_task_info_s
, data
->task_list
, i
)->ptid
,
309 return 0; /* No matching task found. */
312 /* Return the task number of the task running in inferior INF which
313 matches TASK_ID , or zero if the task could not be found. */
316 get_task_number_from_id (CORE_ADDR task_id
, struct inferior
*inf
)
318 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
321 for (i
= 0; i
< VEC_length (ada_task_info_s
, data
->task_list
); i
++)
323 struct ada_task_info
*task_info
=
324 VEC_index (ada_task_info_s
, data
->task_list
, i
);
326 if (task_info
->task_id
== task_id
)
330 /* Task not found. Return 0. */
334 /* Return non-zero if TASK_NUM is a valid task number. */
337 valid_task_id (int task_num
)
339 struct ada_tasks_inferior_data
*data
;
341 ada_build_task_list ();
342 data
= get_ada_tasks_inferior_data (current_inferior ());
344 && task_num
<= VEC_length (ada_task_info_s
, data
->task_list
));
347 /* Return non-zero iff the task STATE corresponds to a non-terminated
351 ada_task_is_alive (struct ada_task_info
*task_info
)
353 return (task_info
->state
!= Terminated
);
356 /* Search through the list of known tasks for the one whose ptid is
357 PTID, and return it. Return NULL if the task was not found. */
359 struct ada_task_info
*
360 ada_get_task_info_from_ptid (ptid_t ptid
)
363 struct ada_task_info
*task
;
364 struct ada_tasks_inferior_data
*data
;
366 ada_build_task_list ();
367 data
= get_ada_tasks_inferior_data (current_inferior ());
368 nb_tasks
= VEC_length (ada_task_info_s
, data
->task_list
);
370 for (i
= 0; i
< nb_tasks
; i
++)
372 task
= VEC_index (ada_task_info_s
, data
->task_list
, i
);
373 if (ptid_equal (task
->ptid
, ptid
))
380 /* Call the ITERATOR function once for each Ada task that hasn't been
384 iterate_over_live_ada_tasks (ada_task_list_iterator_ftype
*iterator
)
387 struct ada_task_info
*task
;
388 struct ada_tasks_inferior_data
*data
;
390 ada_build_task_list ();
391 data
= get_ada_tasks_inferior_data (current_inferior ());
392 nb_tasks
= VEC_length (ada_task_info_s
, data
->task_list
);
394 for (i
= 0; i
< nb_tasks
; i
++)
396 task
= VEC_index (ada_task_info_s
, data
->task_list
, i
);
397 if (!ada_task_is_alive (task
))
403 /* Extract the contents of the value as a string whose length is LENGTH,
404 and store the result in DEST. */
407 value_as_string (char *dest
, struct value
*val
, int length
)
409 memcpy (dest
, value_contents (val
), length
);
413 /* Extract the string image from the fat string corresponding to VAL,
414 and store it in DEST. If the string length is greater than MAX_LEN,
415 then truncate the result to the first MAX_LEN characters of the fat
419 read_fat_string_value (char *dest
, struct value
*val
, int max_len
)
421 struct value
*array_val
;
422 struct value
*bounds_val
;
425 /* The following variables are made static to avoid recomputing them
426 each time this function is called. */
427 static int initialize_fieldnos
= 1;
428 static int array_fieldno
;
429 static int bounds_fieldno
;
430 static int upper_bound_fieldno
;
432 /* Get the index of the fields that we will need to read in order
433 to extract the string from the fat string. */
434 if (initialize_fieldnos
)
436 struct type
*type
= value_type (val
);
437 struct type
*bounds_type
;
439 array_fieldno
= ada_get_field_index (type
, "P_ARRAY", 0);
440 bounds_fieldno
= ada_get_field_index (type
, "P_BOUNDS", 0);
442 bounds_type
= TYPE_FIELD_TYPE (type
, bounds_fieldno
);
443 if (TYPE_CODE (bounds_type
) == TYPE_CODE_PTR
)
444 bounds_type
= TYPE_TARGET_TYPE (bounds_type
);
445 if (TYPE_CODE (bounds_type
) != TYPE_CODE_STRUCT
)
446 error (_("Unknown task name format. Aborting"));
447 upper_bound_fieldno
= ada_get_field_index (bounds_type
, "UB0", 0);
449 initialize_fieldnos
= 0;
452 /* Get the size of the task image by checking the value of the bounds.
453 The lower bound is always 1, so we only need to read the upper bound. */
454 bounds_val
= value_ind (value_field (val
, bounds_fieldno
));
455 len
= value_as_long (value_field (bounds_val
, upper_bound_fieldno
));
457 /* Make sure that we do not read more than max_len characters... */
461 /* Extract LEN characters from the fat string. */
462 array_val
= value_ind (value_field (val
, array_fieldno
));
463 read_memory (value_address (array_val
), (gdb_byte
*) dest
, len
);
465 /* Add the NUL character to close the string. */
469 /* Get, from the debugging information, the type description of all types
470 related to the Ada Task Control Block that are needed in order to
471 read the list of known tasks in the Ada runtime. If all of the info
472 needed to do so is found, then save that info in the module's per-
473 program-space data, and return NULL. Otherwise, if any information
474 cannot be found, leave the per-program-space data untouched, and
475 return an error message explaining what was missing (that error
476 message does NOT need to be deallocated). */
479 ada_get_tcb_types_info (void)
482 struct type
*common_type
;
483 struct type
*ll_type
;
484 struct type
*call_type
;
485 struct atcb_fieldnos fieldnos
;
486 struct ada_tasks_pspace_data
*pspace_data
;
488 const char *atcb_name
= "system__tasking__ada_task_control_block___XVE";
489 const char *atcb_name_fixed
= "system__tasking__ada_task_control_block";
490 const char *common_atcb_name
= "system__tasking__common_atcb";
491 const char *private_data_name
= "system__task_primitives__private_data";
492 const char *entry_call_record_name
= "system__tasking__entry_call_record";
494 /* ATCB symbols may be found in several compilation units. As we
495 are only interested in one instance, use standard (literal,
496 C-like) lookups to get the first match. */
498 struct symbol
*atcb_sym
=
499 lookup_symbol_in_language (atcb_name
, NULL
, STRUCT_DOMAIN
,
500 language_c
, NULL
).symbol
;
501 const struct symbol
*common_atcb_sym
=
502 lookup_symbol_in_language (common_atcb_name
, NULL
, STRUCT_DOMAIN
,
503 language_c
, NULL
).symbol
;
504 const struct symbol
*private_data_sym
=
505 lookup_symbol_in_language (private_data_name
, NULL
, STRUCT_DOMAIN
,
506 language_c
, NULL
).symbol
;
507 const struct symbol
*entry_call_record_sym
=
508 lookup_symbol_in_language (entry_call_record_name
, NULL
, STRUCT_DOMAIN
,
509 language_c
, NULL
).symbol
;
511 if (atcb_sym
== NULL
|| atcb_sym
->type
== NULL
)
513 /* In Ravenscar run-time libs, the ATCB does not have a dynamic
514 size, so the symbol name differs. */
515 atcb_sym
= lookup_symbol_in_language (atcb_name_fixed
, NULL
,
516 STRUCT_DOMAIN
, language_c
,
519 if (atcb_sym
== NULL
|| atcb_sym
->type
== NULL
)
520 return _("Cannot find Ada_Task_Control_Block type");
522 type
= atcb_sym
->type
;
526 /* Get a static representation of the type record
527 Ada_Task_Control_Block. */
528 type
= atcb_sym
->type
;
529 type
= ada_template_to_fixed_record_type_1 (type
, NULL
, 0, NULL
, 0);
532 if (common_atcb_sym
== NULL
|| common_atcb_sym
->type
== NULL
)
533 return _("Cannot find Common_ATCB type");
534 if (private_data_sym
== NULL
|| private_data_sym
->type
== NULL
)
535 return _("Cannot find Private_Data type");
536 if (entry_call_record_sym
== NULL
|| entry_call_record_sym
->type
== NULL
)
537 return _("Cannot find Entry_Call_Record type");
539 /* Get the type for Ada_Task_Control_Block.Common. */
540 common_type
= common_atcb_sym
->type
;
542 /* Get the type for Ada_Task_Control_Bloc.Common.Call.LL. */
543 ll_type
= private_data_sym
->type
;
545 /* Get the type for Common_ATCB.Call.all. */
546 call_type
= entry_call_record_sym
->type
;
548 /* Get the field indices. */
549 fieldnos
.common
= ada_get_field_index (type
, "common", 0);
550 fieldnos
.entry_calls
= ada_get_field_index (type
, "entry_calls", 1);
551 fieldnos
.atc_nesting_level
=
552 ada_get_field_index (type
, "atc_nesting_level", 1);
553 fieldnos
.state
= ada_get_field_index (common_type
, "state", 0);
554 fieldnos
.parent
= ada_get_field_index (common_type
, "parent", 1);
555 fieldnos
.priority
= ada_get_field_index (common_type
, "base_priority", 0);
556 fieldnos
.image
= ada_get_field_index (common_type
, "task_image", 1);
557 fieldnos
.image_len
= ada_get_field_index (common_type
, "task_image_len", 1);
558 fieldnos
.activation_link
= ada_get_field_index (common_type
,
559 "activation_link", 1);
560 fieldnos
.call
= ada_get_field_index (common_type
, "call", 1);
561 fieldnos
.ll
= ada_get_field_index (common_type
, "ll", 0);
562 fieldnos
.base_cpu
= ada_get_field_index (common_type
, "base_cpu", 0);
563 fieldnos
.ll_thread
= ada_get_field_index (ll_type
, "thread", 0);
564 fieldnos
.ll_lwp
= ada_get_field_index (ll_type
, "lwp", 1);
565 fieldnos
.call_self
= ada_get_field_index (call_type
, "self", 0);
567 /* On certain platforms such as x86-windows, the "lwp" field has been
568 named "thread_id". This field will likely be renamed in the future,
569 but we need to support both possibilities to avoid an unnecessary
570 dependency on a recent compiler. We therefore try locating the
571 "thread_id" field in place of the "lwp" field if we did not find
573 if (fieldnos
.ll_lwp
< 0)
574 fieldnos
.ll_lwp
= ada_get_field_index (ll_type
, "thread_id", 1);
576 /* Set all the out parameters all at once, now that we are certain
577 that there are no potential error() anymore. */
578 pspace_data
= get_ada_tasks_pspace_data (current_program_space
);
579 pspace_data
->initialized_p
= 1;
580 pspace_data
->atcb_type
= type
;
581 pspace_data
->atcb_common_type
= common_type
;
582 pspace_data
->atcb_ll_type
= ll_type
;
583 pspace_data
->atcb_call_type
= call_type
;
584 pspace_data
->atcb_fieldno
= fieldnos
;
588 /* Build the PTID of the task from its COMMON_VALUE, which is the "Common"
589 component of its ATCB record. This PTID needs to match the PTID used
590 by the thread layer. */
593 ptid_from_atcb_common (struct value
*common_value
)
597 struct value
*ll_value
;
599 const struct ada_tasks_pspace_data
*pspace_data
600 = get_ada_tasks_pspace_data (current_program_space
);
602 ll_value
= value_field (common_value
, pspace_data
->atcb_fieldno
.ll
);
604 if (pspace_data
->atcb_fieldno
.ll_lwp
>= 0)
605 lwp
= value_as_address (value_field (ll_value
,
606 pspace_data
->atcb_fieldno
.ll_lwp
));
607 thread
= value_as_long (value_field (ll_value
,
608 pspace_data
->atcb_fieldno
.ll_thread
));
610 ptid
= target_get_ada_task_ptid (lwp
, thread
);
615 /* Read the ATCB data of a given task given its TASK_ID (which is in practice
616 the address of its assocated ATCB record), and store the result inside
620 read_atcb (CORE_ADDR task_id
, struct ada_task_info
*task_info
)
622 struct value
*tcb_value
;
623 struct value
*common_value
;
624 struct value
*atc_nesting_level_value
;
625 struct value
*entry_calls_value
;
626 struct value
*entry_calls_value_element
;
627 int called_task_fieldno
= -1;
628 static const char ravenscar_task_name
[] = "Ravenscar task";
629 const struct ada_tasks_pspace_data
*pspace_data
630 = get_ada_tasks_pspace_data (current_program_space
);
632 if (!pspace_data
->initialized_p
)
634 const char *err_msg
= ada_get_tcb_types_info ();
637 error (_("%s. Aborting"), err_msg
);
640 tcb_value
= value_from_contents_and_address (pspace_data
->atcb_type
,
642 common_value
= value_field (tcb_value
, pspace_data
->atcb_fieldno
.common
);
644 /* Fill in the task_id. */
646 task_info
->task_id
= task_id
;
648 /* Compute the name of the task.
650 Depending on the GNAT version used, the task image is either a fat
651 string, or a thin array of characters. Older versions of GNAT used
652 to use fat strings, and therefore did not need an extra field in
653 the ATCB to store the string length. For efficiency reasons, newer
654 versions of GNAT replaced the fat string by a static buffer, but this
655 also required the addition of a new field named "Image_Len" containing
656 the length of the task name. The method used to extract the task name
657 is selected depending on the existence of this field.
659 In some run-time libs (e.g. Ravenscar), the name is not in the ATCB;
660 we may want to get it from the first user frame of the stack. For now,
661 we just give a dummy name. */
663 if (pspace_data
->atcb_fieldno
.image_len
== -1)
665 if (pspace_data
->atcb_fieldno
.image
>= 0)
666 read_fat_string_value (task_info
->name
,
667 value_field (common_value
,
668 pspace_data
->atcb_fieldno
.image
),
669 sizeof (task_info
->name
) - 1);
672 struct bound_minimal_symbol msym
;
674 msym
= lookup_minimal_symbol_by_pc (task_id
);
677 const char *full_name
= MSYMBOL_LINKAGE_NAME (msym
.minsym
);
678 const char *task_name
= full_name
;
681 /* Strip the prefix. */
682 for (p
= full_name
; *p
; p
++)
683 if (p
[0] == '_' && p
[1] == '_')
686 /* Copy the task name. */
687 strncpy (task_info
->name
, task_name
, sizeof (task_info
->name
));
688 task_info
->name
[sizeof (task_info
->name
) - 1] = 0;
692 /* No symbol found. Use a default name. */
693 strcpy (task_info
->name
, ravenscar_task_name
);
699 int len
= value_as_long
700 (value_field (common_value
,
701 pspace_data
->atcb_fieldno
.image_len
));
703 value_as_string (task_info
->name
,
704 value_field (common_value
,
705 pspace_data
->atcb_fieldno
.image
),
709 /* Compute the task state and priority. */
712 value_as_long (value_field (common_value
,
713 pspace_data
->atcb_fieldno
.state
));
714 task_info
->priority
=
715 value_as_long (value_field (common_value
,
716 pspace_data
->atcb_fieldno
.priority
));
718 /* If the ATCB contains some information about the parent task,
719 then compute it as well. Otherwise, zero. */
721 if (pspace_data
->atcb_fieldno
.parent
>= 0)
723 value_as_address (value_field (common_value
,
724 pspace_data
->atcb_fieldno
.parent
));
726 task_info
->parent
= 0;
729 /* If the ATCB contains some information about entry calls, then
730 compute the "called_task" as well. Otherwise, zero. */
732 if (pspace_data
->atcb_fieldno
.atc_nesting_level
> 0
733 && pspace_data
->atcb_fieldno
.entry_calls
> 0)
735 /* Let My_ATCB be the Ada task control block of a task calling the
736 entry of another task; then the Task_Id of the called task is
737 in My_ATCB.Entry_Calls (My_ATCB.ATC_Nesting_Level).Called_Task. */
738 atc_nesting_level_value
=
739 value_field (tcb_value
, pspace_data
->atcb_fieldno
.atc_nesting_level
);
741 ada_coerce_to_simple_array_ptr
742 (value_field (tcb_value
, pspace_data
->atcb_fieldno
.entry_calls
));
743 entry_calls_value_element
=
744 value_subscript (entry_calls_value
,
745 value_as_long (atc_nesting_level_value
));
746 called_task_fieldno
=
747 ada_get_field_index (value_type (entry_calls_value_element
),
749 task_info
->called_task
=
750 value_as_address (value_field (entry_calls_value_element
,
751 called_task_fieldno
));
755 task_info
->called_task
= 0;
758 /* If the ATCB cotnains some information about RV callers,
759 then compute the "caller_task". Otherwise, zero. */
761 task_info
->caller_task
= 0;
762 if (pspace_data
->atcb_fieldno
.call
>= 0)
764 /* Get the ID of the caller task from Common_ATCB.Call.all.Self.
765 If Common_ATCB.Call is null, then there is no caller. */
766 const CORE_ADDR call
=
767 value_as_address (value_field (common_value
,
768 pspace_data
->atcb_fieldno
.call
));
769 struct value
*call_val
;
774 value_from_contents_and_address (pspace_data
->atcb_call_type
,
776 task_info
->caller_task
=
778 (value_field (call_val
, pspace_data
->atcb_fieldno
.call_self
));
783 = value_as_long (value_field (common_value
,
784 pspace_data
->atcb_fieldno
.base_cpu
));
786 /* And finally, compute the task ptid. Note that there are situations
787 where this cannot be determined:
788 - The task is no longer alive - the ptid is irrelevant;
789 - We are debugging a core file - the thread is not always
790 completely preserved for us to link back a task to its
791 underlying thread. Since we do not support task switching
792 when debugging core files anyway, we don't need to compute
794 In either case, we don't need that ptid, and it is just good enough
795 to set it to null_ptid. */
797 if (target_has_execution
&& ada_task_is_alive (task_info
))
798 task_info
->ptid
= ptid_from_atcb_common (common_value
);
800 task_info
->ptid
= null_ptid
;
803 /* Read the ATCB info of the given task (identified by TASK_ID), and
804 add the result to the given inferior's TASK_LIST. */
807 add_ada_task (CORE_ADDR task_id
, struct inferior
*inf
)
809 struct ada_task_info task_info
;
810 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
812 read_atcb (task_id
, &task_info
);
813 VEC_safe_push (ada_task_info_s
, data
->task_list
, &task_info
);
816 /* Read the Known_Tasks array from the inferior memory, and store
817 it in the current inferior's TASK_LIST. Return non-zero upon success. */
820 read_known_tasks_array (struct ada_tasks_inferior_data
*data
)
822 const int target_ptr_byte
= TYPE_LENGTH (data
->known_tasks_element
);
823 const int known_tasks_size
= target_ptr_byte
* data
->known_tasks_length
;
824 gdb_byte
*known_tasks
= (gdb_byte
*) alloca (known_tasks_size
);
827 /* Build a new list by reading the ATCBs from the Known_Tasks array
828 in the Ada runtime. */
829 read_memory (data
->known_tasks_addr
, known_tasks
, known_tasks_size
);
830 for (i
= 0; i
< data
->known_tasks_length
; i
++)
833 extract_typed_address (known_tasks
+ i
* target_ptr_byte
,
834 data
->known_tasks_element
);
837 add_ada_task (task_id
, current_inferior ());
843 /* Read the known tasks from the inferior memory, and store it in
844 the current inferior's TASK_LIST. Return non-zero upon success. */
847 read_known_tasks_list (struct ada_tasks_inferior_data
*data
)
849 const int target_ptr_byte
= TYPE_LENGTH (data
->known_tasks_element
);
850 gdb_byte
*known_tasks
= (gdb_byte
*) alloca (target_ptr_byte
);
852 const struct ada_tasks_pspace_data
*pspace_data
853 = get_ada_tasks_pspace_data (current_program_space
);
856 if (pspace_data
->atcb_fieldno
.activation_link
< 0)
859 /* Build a new list by reading the ATCBs. Read head of the list. */
860 read_memory (data
->known_tasks_addr
, known_tasks
, target_ptr_byte
);
861 task_id
= extract_typed_address (known_tasks
, data
->known_tasks_element
);
864 struct value
*tcb_value
;
865 struct value
*common_value
;
867 add_ada_task (task_id
, current_inferior ());
869 /* Read the chain. */
870 tcb_value
= value_from_contents_and_address (pspace_data
->atcb_type
,
872 common_value
= value_field (tcb_value
, pspace_data
->atcb_fieldno
.common
);
873 task_id
= value_as_address
874 (value_field (common_value
,
875 pspace_data
->atcb_fieldno
.activation_link
));
881 /* Set all fields of the current inferior ada-tasks data pointed by DATA.
882 Do nothing if those fields are already set and still up to date. */
885 ada_tasks_inferior_data_sniffer (struct ada_tasks_inferior_data
*data
)
887 struct bound_minimal_symbol msym
;
890 /* Return now if already set. */
891 if (data
->known_tasks_kind
!= ADA_TASKS_UNKNOWN
)
896 msym
= lookup_minimal_symbol (KNOWN_TASKS_NAME
, NULL
, NULL
);
897 if (msym
.minsym
!= NULL
)
899 data
->known_tasks_kind
= ADA_TASKS_ARRAY
;
900 data
->known_tasks_addr
= BMSYMBOL_VALUE_ADDRESS (msym
);
902 /* Try to get pointer type and array length from the symtab. */
903 sym
= lookup_symbol_in_language (KNOWN_TASKS_NAME
, NULL
, VAR_DOMAIN
,
904 language_c
, NULL
).symbol
;
908 struct type
*type
= check_typedef (SYMBOL_TYPE (sym
));
909 struct type
*eltype
= NULL
;
910 struct type
*idxtype
= NULL
;
912 if (TYPE_CODE (type
) == TYPE_CODE_ARRAY
)
913 eltype
= check_typedef (TYPE_TARGET_TYPE (type
));
915 && TYPE_CODE (eltype
) == TYPE_CODE_PTR
)
916 idxtype
= check_typedef (TYPE_INDEX_TYPE (type
));
918 && !TYPE_LOW_BOUND_UNDEFINED (idxtype
)
919 && !TYPE_HIGH_BOUND_UNDEFINED (idxtype
))
921 data
->known_tasks_element
= eltype
;
922 data
->known_tasks_length
=
923 TYPE_HIGH_BOUND (idxtype
) - TYPE_LOW_BOUND (idxtype
) + 1;
928 /* Fallback to default values. The runtime may have been stripped (as
929 in some distributions), but it is likely that the executable still
930 contains debug information on the task type (due to implicit with of
932 data
->known_tasks_element
=
933 builtin_type (target_gdbarch ())->builtin_data_ptr
;
934 data
->known_tasks_length
= MAX_NUMBER_OF_KNOWN_TASKS
;
941 msym
= lookup_minimal_symbol (KNOWN_TASKS_LIST
, NULL
, NULL
);
942 if (msym
.minsym
!= NULL
)
944 data
->known_tasks_kind
= ADA_TASKS_LIST
;
945 data
->known_tasks_addr
= BMSYMBOL_VALUE_ADDRESS (msym
);
946 data
->known_tasks_length
= 1;
948 sym
= lookup_symbol_in_language (KNOWN_TASKS_LIST
, NULL
, VAR_DOMAIN
,
949 language_c
, NULL
).symbol
;
950 if (sym
!= NULL
&& SYMBOL_VALUE_ADDRESS (sym
) != 0)
953 struct type
*type
= check_typedef (SYMBOL_TYPE (sym
));
955 if (TYPE_CODE (type
) == TYPE_CODE_PTR
)
957 data
->known_tasks_element
= type
;
962 /* Fallback to default values. */
963 data
->known_tasks_element
=
964 builtin_type (target_gdbarch ())->builtin_data_ptr
;
965 data
->known_tasks_length
= 1;
969 /* Can't find tasks. */
971 data
->known_tasks_kind
= ADA_TASKS_NOT_FOUND
;
972 data
->known_tasks_addr
= 0;
975 /* Read the known tasks from the current inferior's memory, and store it
976 in the current inferior's data TASK_LIST.
977 Return non-zero upon success. */
980 read_known_tasks (void)
982 struct ada_tasks_inferior_data
*data
=
983 get_ada_tasks_inferior_data (current_inferior ());
985 /* Step 1: Clear the current list, if necessary. */
986 VEC_truncate (ada_task_info_s
, data
->task_list
, 0);
988 /* Step 2: do the real work.
989 If the application does not use task, then no more needs to be done.
990 It is important to have the task list cleared (see above) before we
991 return, as we don't want a stale task list to be used... This can
992 happen for instance when debugging a non-multitasking program after
993 having debugged a multitasking one. */
994 ada_tasks_inferior_data_sniffer (data
);
995 gdb_assert (data
->known_tasks_kind
!= ADA_TASKS_UNKNOWN
);
997 switch (data
->known_tasks_kind
)
999 case ADA_TASKS_NOT_FOUND
: /* Tasking not in use in inferior. */
1001 case ADA_TASKS_ARRAY
:
1002 return read_known_tasks_array (data
);
1003 case ADA_TASKS_LIST
:
1004 return read_known_tasks_list (data
);
1007 /* Step 3: Set task_list_valid_p, to avoid re-reading the Known_Tasks
1008 array unless needed. Then report a success. */
1009 data
->task_list_valid_p
= 1;
1014 /* Build the task_list by reading the Known_Tasks array from
1015 the inferior, and return the number of tasks in that list
1016 (zero means that the program is not using tasking at all). */
1019 ada_build_task_list (void)
1021 struct ada_tasks_inferior_data
*data
;
1023 if (!target_has_stack
)
1024 error (_("Cannot inspect Ada tasks when program is not running"));
1026 data
= get_ada_tasks_inferior_data (current_inferior ());
1027 if (!data
->task_list_valid_p
)
1028 read_known_tasks ();
1030 return VEC_length (ada_task_info_s
, data
->task_list
);
1033 /* Print a table providing a short description of all Ada tasks
1034 running inside inferior INF. If ARG_STR is set, it will be
1035 interpreted as a task number, and the table will be limited to
1039 print_ada_task_info (struct ui_out
*uiout
,
1041 struct inferior
*inf
)
1043 struct ada_tasks_inferior_data
*data
;
1044 int taskno
, nb_tasks
;
1048 if (ada_build_task_list () == 0)
1050 uiout
->message (_("Your application does not use any Ada tasks.\n"));
1054 if (arg_str
!= NULL
&& arg_str
[0] != '\0')
1055 taskno_arg
= value_as_long (parse_and_eval (arg_str
));
1057 if (uiout
->is_mi_like_p ())
1058 /* In GDB/MI mode, we want to provide the thread ID corresponding
1059 to each task. This allows clients to quickly find the thread
1060 associated to any task, which is helpful for commands that
1061 take a --thread argument. However, in order to be able to
1062 provide that thread ID, the thread list must be up to date
1064 target_update_thread_list ();
1066 data
= get_ada_tasks_inferior_data (inf
);
1068 /* Compute the number of tasks that are going to be displayed
1069 in the output. If an argument was given, there will be
1070 at most 1 entry. Otherwise, there will be as many entries
1071 as we have tasks. */
1075 && taskno_arg
<= VEC_length (ada_task_info_s
, data
->task_list
))
1081 nb_tasks
= VEC_length (ada_task_info_s
, data
->task_list
);
1083 nb_columns
= uiout
->is_mi_like_p () ? 8 : 7;
1084 ui_out_emit_table
table_emitter (uiout
, nb_columns
, nb_tasks
, "tasks");
1085 uiout
->table_header (1, ui_left
, "current", "");
1086 uiout
->table_header (3, ui_right
, "id", "ID");
1087 uiout
->table_header (9, ui_right
, "task-id", "TID");
1088 /* The following column is provided in GDB/MI mode only because
1089 it is only really useful in that mode, and also because it
1090 allows us to keep the CLI output shorter and more compact. */
1091 if (uiout
->is_mi_like_p ())
1092 uiout
->table_header (4, ui_right
, "thread-id", "");
1093 uiout
->table_header (4, ui_right
, "parent-id", "P-ID");
1094 uiout
->table_header (3, ui_right
, "priority", "Pri");
1095 uiout
->table_header (22, ui_left
, "state", "State");
1096 /* Use ui_noalign for the last column, to prevent the CLI uiout
1097 from printing an extra space at the end of each row. This
1098 is a bit of a hack, but does get the job done. */
1099 uiout
->table_header (1, ui_noalign
, "name", "Name");
1100 uiout
->table_body ();
1103 taskno
<= VEC_length (ada_task_info_s
, data
->task_list
);
1106 const struct ada_task_info
*const task_info
=
1107 VEC_index (ada_task_info_s
, data
->task_list
, taskno
- 1);
1110 gdb_assert (task_info
!= NULL
);
1112 /* If the user asked for the output to be restricted
1113 to one task only, and this is not the task, skip
1115 if (taskno_arg
&& taskno
!= taskno_arg
)
1118 ui_out_emit_tuple
tuple_emitter (uiout
, NULL
);
1120 /* Print a star if this task is the current task (or the task
1121 currently selected). */
1122 if (ptid_equal (task_info
->ptid
, inferior_ptid
))
1123 uiout
->field_string ("current", "*");
1125 uiout
->field_skip ("current");
1127 /* Print the task number. */
1128 uiout
->field_int ("id", taskno
);
1130 /* Print the Task ID. */
1131 uiout
->field_fmt ("task-id", "%9lx", (long) task_info
->task_id
);
1133 /* Print the associated Thread ID. */
1134 if (uiout
->is_mi_like_p ())
1136 const int thread_id
= ptid_to_global_thread_id (task_info
->ptid
);
1139 uiout
->field_int ("thread-id", thread_id
);
1141 /* This should never happen unless there is a bug somewhere,
1142 but be resilient when that happens. */
1143 uiout
->field_skip ("thread-id");
1146 /* Print the ID of the parent task. */
1147 parent_id
= get_task_number_from_id (task_info
->parent
, inf
);
1149 uiout
->field_int ("parent-id", parent_id
);
1151 uiout
->field_skip ("parent-id");
1153 /* Print the base priority of the task. */
1154 uiout
->field_int ("priority", task_info
->priority
);
1156 /* Print the task current state. */
1157 if (task_info
->caller_task
)
1158 uiout
->field_fmt ("state",
1159 _("Accepting RV with %-4d"),
1160 get_task_number_from_id (task_info
->caller_task
,
1162 else if (task_info
->state
== Entry_Caller_Sleep
1163 && task_info
->called_task
)
1164 uiout
->field_fmt ("state",
1165 _("Waiting on RV with %-3d"),
1166 get_task_number_from_id (task_info
->called_task
,
1169 uiout
->field_string ("state", task_states
[task_info
->state
]);
1171 /* Finally, print the task name. */
1172 uiout
->field_fmt ("name",
1174 task_info
->name
[0] != '\0' ? task_info
->name
1181 /* Print a detailed description of the Ada task whose ID is TASKNO_STR
1182 for the given inferior (INF). */
1185 info_task (struct ui_out
*uiout
, const char *taskno_str
, struct inferior
*inf
)
1187 const int taskno
= value_as_long (parse_and_eval (taskno_str
));
1188 struct ada_task_info
*task_info
;
1189 int parent_taskno
= 0;
1190 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
1192 if (ada_build_task_list () == 0)
1194 uiout
->message (_("Your application does not use any Ada tasks.\n"));
1198 if (taskno
<= 0 || taskno
> VEC_length (ada_task_info_s
, data
->task_list
))
1199 error (_("Task ID %d not known. Use the \"info tasks\" command to\n"
1200 "see the IDs of currently known tasks"), taskno
);
1201 task_info
= VEC_index (ada_task_info_s
, data
->task_list
, taskno
- 1);
1203 /* Print the Ada task ID. */
1204 printf_filtered (_("Ada Task: %s\n"),
1205 paddress (target_gdbarch (), task_info
->task_id
));
1207 /* Print the name of the task. */
1208 if (task_info
->name
[0] != '\0')
1209 printf_filtered (_("Name: %s\n"), task_info
->name
);
1211 printf_filtered (_("<no name>\n"));
1213 /* Print the TID and LWP. */
1214 printf_filtered (_("Thread: %#lx\n"), ptid_get_tid (task_info
->ptid
));
1215 printf_filtered (_("LWP: %#lx\n"), ptid_get_lwp (task_info
->ptid
));
1217 /* If set, print the base CPU. */
1218 if (task_info
->base_cpu
!= 0)
1219 printf_filtered (_("Base CPU: %d\n"), task_info
->base_cpu
);
1221 /* Print who is the parent (if any). */
1222 if (task_info
->parent
!= 0)
1223 parent_taskno
= get_task_number_from_id (task_info
->parent
, inf
);
1226 struct ada_task_info
*parent
=
1227 VEC_index (ada_task_info_s
, data
->task_list
, parent_taskno
- 1);
1229 printf_filtered (_("Parent: %d"), parent_taskno
);
1230 if (parent
->name
[0] != '\0')
1231 printf_filtered (" (%s)", parent
->name
);
1232 printf_filtered ("\n");
1235 printf_filtered (_("No parent\n"));
1237 /* Print the base priority. */
1238 printf_filtered (_("Base Priority: %d\n"), task_info
->priority
);
1240 /* print the task current state. */
1242 int target_taskno
= 0;
1244 if (task_info
->caller_task
)
1246 target_taskno
= get_task_number_from_id (task_info
->caller_task
, inf
);
1247 printf_filtered (_("State: Accepting rendezvous with %d"),
1250 else if (task_info
->state
== Entry_Caller_Sleep
&& task_info
->called_task
)
1252 target_taskno
= get_task_number_from_id (task_info
->called_task
, inf
);
1253 printf_filtered (_("State: Waiting on task %d's entry"),
1257 printf_filtered (_("State: %s"), _(long_task_states
[task_info
->state
]));
1261 struct ada_task_info
*target_task_info
=
1262 VEC_index (ada_task_info_s
, data
->task_list
, target_taskno
- 1);
1264 if (target_task_info
->name
[0] != '\0')
1265 printf_filtered (" (%s)", target_task_info
->name
);
1268 printf_filtered ("\n");
1272 /* If ARG is empty or null, then print a list of all Ada tasks.
1273 Otherwise, print detailed information about the task whose ID
1276 Does nothing if the program doesn't use Ada tasking. */
1279 info_tasks_command (const char *arg
, int from_tty
)
1281 struct ui_out
*uiout
= current_uiout
;
1283 if (arg
== NULL
|| *arg
== '\0')
1284 print_ada_task_info (uiout
, NULL
, current_inferior ());
1286 info_task (uiout
, arg
, current_inferior ());
1289 /* Print a message telling the user id of the current task.
1290 This function assumes that tasking is in use in the inferior. */
1293 display_current_task_id (void)
1295 const int current_task
= ada_get_task_number (inferior_ptid
);
1297 if (current_task
== 0)
1298 printf_filtered (_("[Current task is unknown]\n"));
1300 printf_filtered (_("[Current task is %d]\n"), current_task
);
1303 /* Parse and evaluate TIDSTR into a task id, and try to switch to
1304 that task. Print an error message if the task switch failed. */
1307 task_command_1 (const char *taskno_str
, int from_tty
, struct inferior
*inf
)
1309 const int taskno
= value_as_long (parse_and_eval (taskno_str
));
1310 struct ada_task_info
*task_info
;
1311 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
1313 if (taskno
<= 0 || taskno
> VEC_length (ada_task_info_s
, data
->task_list
))
1314 error (_("Task ID %d not known. Use the \"info tasks\" command to\n"
1315 "see the IDs of currently known tasks"), taskno
);
1316 task_info
= VEC_index (ada_task_info_s
, data
->task_list
, taskno
- 1);
1318 if (!ada_task_is_alive (task_info
))
1319 error (_("Cannot switch to task %d: Task is no longer running"), taskno
);
1321 /* On some platforms, the thread list is not updated until the user
1322 performs a thread-related operation (by using the "info threads"
1323 command, for instance). So this thread list may not be up to date
1324 when the user attempts this task switch. Since we cannot switch
1325 to the thread associated to our task if GDB does not know about
1326 that thread, we need to make sure that any new threads gets added
1327 to the thread list. */
1328 target_update_thread_list ();
1330 /* Verify that the ptid of the task we want to switch to is valid
1331 (in other words, a ptid that GDB knows about). Otherwise, we will
1332 cause an assertion failure later on, when we try to determine
1333 the ptid associated thread_info data. We should normally never
1334 encounter such an error, but the wrong ptid can actually easily be
1335 computed if target_get_ada_task_ptid has not been implemented for
1336 our target (yet). Rather than cause an assertion error in that case,
1337 it's nicer for the user to just refuse to perform the task switch. */
1338 if (!find_thread_ptid (task_info
->ptid
))
1339 error (_("Unable to compute thread ID for task %d.\n"
1340 "Cannot switch to this task."),
1343 switch_to_thread (task_info
->ptid
);
1344 ada_find_printable_frame (get_selected_frame (NULL
));
1345 printf_filtered (_("[Switching to task %d]\n"), taskno
);
1346 print_stack_frame (get_selected_frame (NULL
),
1347 frame_relative_level (get_selected_frame (NULL
)),
1352 /* Print the ID of the current task if TASKNO_STR is empty or NULL.
1353 Otherwise, switch to the task indicated by TASKNO_STR. */
1356 task_command (const char *taskno_str
, int from_tty
)
1358 struct ui_out
*uiout
= current_uiout
;
1360 if (ada_build_task_list () == 0)
1362 uiout
->message (_("Your application does not use any Ada tasks.\n"));
1366 if (taskno_str
== NULL
|| taskno_str
[0] == '\0')
1367 display_current_task_id ();
1370 /* Task switching in core files doesn't work, either because:
1371 1. Thread support is not implemented with core files
1372 2. Thread support is implemented, but the thread IDs created
1373 after having read the core file are not the same as the ones
1374 that were used during the program life, before the crash.
1375 As a consequence, there is no longer a way for the debugger
1376 to find the associated thead ID of any given Ada task.
1377 So, instead of attempting a task switch without giving the user
1378 any clue as to what might have happened, just error-out with
1379 a message explaining that this feature is not supported. */
1380 if (!target_has_execution
)
1382 Task switching not supported when debugging from core files\n\
1383 (use thread support instead)"));
1384 task_command_1 (taskno_str
, from_tty
, current_inferior ());
1388 /* Indicate that the given inferior's task list may have changed,
1389 so invalidate the cache. */
1392 ada_task_list_changed (struct inferior
*inf
)
1394 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
1396 data
->task_list_valid_p
= 0;
1399 /* Invalidate the per-program-space data. */
1402 ada_tasks_invalidate_pspace_data (struct program_space
*pspace
)
1404 get_ada_tasks_pspace_data (pspace
)->initialized_p
= 0;
1407 /* Invalidate the per-inferior data. */
1410 ada_tasks_invalidate_inferior_data (struct inferior
*inf
)
1412 struct ada_tasks_inferior_data
*data
= get_ada_tasks_inferior_data (inf
);
1414 data
->known_tasks_kind
= ADA_TASKS_UNKNOWN
;
1415 data
->task_list_valid_p
= 0;
1418 /* The 'normal_stop' observer notification callback. */
1421 ada_tasks_normal_stop_observer (struct bpstats
*unused_args
, int unused_args2
)
1423 /* The inferior has been resumed, and just stopped. This means that
1424 our task_list needs to be recomputed before it can be used again. */
1425 ada_task_list_changed (current_inferior ());
1428 /* A routine to be called when the objfiles have changed. */
1431 ada_tasks_new_objfile_observer (struct objfile
*objfile
)
1433 struct inferior
*inf
;
1435 /* Invalidate the relevant data in our program-space data. */
1437 if (objfile
== NULL
)
1439 /* All objfiles are being cleared, so we should clear all
1440 our caches for all program spaces. */
1441 struct program_space
*pspace
;
1443 for (pspace
= program_spaces
; pspace
!= NULL
; pspace
= pspace
->next
)
1444 ada_tasks_invalidate_pspace_data (pspace
);
1448 /* The associated program-space data might have changed after
1449 this objfile was added. Invalidate all cached data. */
1450 ada_tasks_invalidate_pspace_data (objfile
->pspace
);
1453 /* Invalidate the per-inferior cache for all inferiors using
1454 this objfile (or, in other words, for all inferiors who have
1455 the same program-space as the objfile's program space).
1456 If all objfiles are being cleared (OBJFILE is NULL), then
1457 clear the caches for all inferiors. */
1459 for (inf
= inferior_list
; inf
!= NULL
; inf
= inf
->next
)
1460 if (objfile
== NULL
|| inf
->pspace
== objfile
->pspace
)
1461 ada_tasks_invalidate_inferior_data (inf
);
1465 _initialize_tasks (void)
1467 ada_tasks_pspace_data_handle
= register_program_space_data ();
1468 ada_tasks_inferior_data_handle
= register_inferior_data ();
1470 /* Attach various observers. */
1471 observer_attach_normal_stop (ada_tasks_normal_stop_observer
);
1472 observer_attach_new_objfile (ada_tasks_new_objfile_observer
);
1474 /* Some new commands provided by this module. */
1475 add_info ("tasks", info_tasks_command
,
1476 _("Provide information about all known Ada tasks"));
1477 add_cmd ("task", class_run
, task_command
,
1478 _("Use this command to switch between Ada tasks.\n\
1479 Without argument, this command simply prints the current task ID"),