[RFA/Ada] Implement Ada tasking support

Joel Brobecker
2008-09-22T23:33:19Z

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Hello,

Following our re-design of the ada-tasks module a while back to be
submittable, I think it is now time to contribute this code.

Ada is one of these languages that includes tasking constructions
built in to the language. While in C we use a thread library,
in Ada, we use what is called "tasks". What this new module provides
is support for examining these tasks:

1. Getting the list of tasks and their current state
2. Switching from task to task

(1) is achieved by poking into an array in the GNAT Tasking runtime
named System.Tasking.Debug.Known_Tasks. We rely on the debugging
information to find how the Ada Task Control Block structure is
laid out, and get the pieces of info that we are looking at.
This part requires a little bit of code, particularly since
we try to accomodate maybe older versions of the GNAT runtime too.
But the code itself isn't very complicated. Just walking through
the type structures, and storing the information in a list of our
own.

(2) is a little more tricky - basically, what we need to do is relate
the information in each Ada Task Control Block (ATCB) back to
the associated thread. In practice, there are two fields, the
"thread" field, and the "LWP" field that we can use, whose content,
meaning and even availability depends on the target, and transform
that into the ptid of the corresponding thread. The good news is
that we know fairly well, for each target, what to use and how,
in order to get that ptid. So this strongly suggested a target
method.

Pretty much all of the code is contained in one file: ada-tasks.c.
The rest is pretty much adding the new target method and providing
an implementation.

If there is a piece on which I'd like some feedback on, it's part (2).
I am including an implementation for Linux targets. It's one of the
less simple ones, just to show you what it would look like. Other
target will be a simple assembly of the information provided. Once
the principle is confirmed and this patch goes in, I can submit support
for the others.

I will also attach a patch for the documentation. But here is a summary
of the commands that are being added:

* info tasks: Prints the list of Ada tasks, and a short description
of each one of them. For instance:

(gdb) info tasks
ID TID P-ID Pri State Name
1 8089008 0 48 Child Termination Wait main_task
2 8089858 1 48 Accept Statement my_callee
* 3 808c9a8 1 48 Running my_caller

* info task TASKNO: Prints a more verbose description of a task:

(gdb) info tasks 3
Ada Task: 808c9a8
Name: my_caller
Thread: 0
LWP: 0x2bd0
Parent: 1 (main_task)
Base Priority: 48
State: Runnable

* task [TASKNO]: Switch to the given task (by switching to the
associated thread). If TASKNO is omitted, then print the task
number of the current task. For instance:

(gdb) task
[Current task is 3]
(gdb) task 1
[Switching to task 1]
#3 0x0804a21a in task_switch () at task_switch.adb:55
55 end Task_Switch;

I should also say that this patch introduces a couple of uses
of current_gdbarch. Both of them are in the same function, so I should
probably make it into one instance. Will do before committing.
However, the real issue is how to get the right gdbarch in this case.
Ulrich?

I have omitted the part that allows you to restrict a breakpoint to
a given task ("break LINESPEC task TASKNO") for now, but will soon
start discussing this if this goes in.

Apart from that, I think that's it for the introduction to this patch.
I hope we can make it part of GDB soon.

gdb/:
2008-09-22 Joel Brobecker <brobecker@adacore.com>

* target.h (struct target_ops): Add new field to_get_ada_task_ptid.
(target_get_ada_task_ptid): New macro.
* target.c (default_get_ada_task_ptid): New function.
(update_current_target): Inherit field default_get_ada_task_ptid.
(update_current_target): Make default_get_ada_task_ptid the default
value for field to_get_ada_task_ptid.
* ada-lang.h (struct task_control_block): Delete. Never used.
(struct task_ptid, task_ptid_t, struct task_entry, task_list):
Likewise.
(struct ada_task_info): New.
(ada_task_is_alive, ada_find_printable_frame)
(ada_task_list_iterator_ftype, iterate_over_live_ada_tasks): Add
declarations.
(ada_build_task_list): Update prototype.
(init_task_list, ada_is_exception_breakpoint): Remove prototypes.
* ada-lang.c (ada_find_printable_frame): Make non-static.
* ada-tasks.c: New file.
* Makefile.in (SFILES): Add ada-tasks.c.
(COMMON_OBS): Add ada-tasks.o.
* linux-thread-db.c (thread_db_find_thread_from_tid)
(thread_db_get_ada_task_ptid): New functions.
(init_thread_db_ops): Set thread_db_ops.to_get_ada_task_ptid.

This change affects the completion testcase a little bit in an expected
way. Adjusted thusly:

gdb/testsuite:
2008-09-22 Joel Brobecker <brobecker@adacore.com>

* gdb.base/completion.exp: Update expected output following
the addition of the "info tasks" command.

Tested on x86-linux. No regression. I will also provide a simple
testcase that have been very useful to me in the past few years.
For when the patch goes in.

Finally, the documentation:
gdb/doc:

2008-09-22 Joel Brobecker <brobecker@adacore.com>

* gdb.texinfo (Ada Tasks, Ada Tasks and Core Files): New nodes.

OK to commit?

Thanks,
--
Joel

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diff -r b2b21339d264 gdb/target.h
--- a/gdb/target.h Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/target.h Mon Sep 22 15:50:06 2008 -0700
@@ -505,6 +505,12 @@ struct target_ops
was available. */
const struct target_desc *(*to_read_description) (struct target_ops *ops);

+ /* Build the PTID of the thread on which a given task is running,
+ based on LWP and THREAD. These values are extracted from the
+ task Private_Data section of the Ada Task Control Block, and
+ their interpretation depends on the target. */
+ ptid_t (*to_get_ada_task_ptid) (long lwp, long thread);
+
/* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
Return 0 if *READPTR is already at the end of the buffer.
Return -1 if there is insufficient buffer for a whole entry.
@@ -1129,6 +1135,9 @@ extern int target_stopped_data_address_p

extern const struct target_desc *target_read_description (struct target_ops *);

+#define target_get_ada_task_ptid(lwp, tid) \
+ (*current_target.to_get_ada_task_ptid) (lwp,tid)
+
/* Utility implementation of searching memory. */
extern int simple_search_memory (struct target_ops* ops,
CORE_ADDR start_addr,
diff -r b2b21339d264 gdb/target.c
--- a/gdb/target.c Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/target.c Mon Sep 22 15:50:06 2008 -0700
@@ -356,6 +356,12 @@ kill_or_be_killed (int from_tty)
tcomplain ();
}

+ptid_t
+default_get_ada_task_ptid (long lwp, long tid)
+{
+ return ptid_build (ptid_get_pid (inferior_ptid), lwp, tid);
+}
+
/* Go through the target stack from top to bottom, copying over zero
entries in current_target, then filling in still empty entries. In
effect, we are doing class inheritance through the pushed target
@@ -461,6 +467,7 @@ update_current_target (void)
INHERIT (to_make_corefile_notes, t);
INHERIT (to_get_thread_local_address, t);
/* Do not inherit to_read_description. */
+ INHERIT (to_get_ada_task_ptid, t);
/* Do not inherit to_search_memory. */
INHERIT (to_magic, t);
/* Do not inherit to_memory_map. */
@@ -626,6 +633,9 @@ update_current_target (void)
(int (*) (int))
return_one);
current_target.to_read_description = NULL;
+ de_fault (to_get_ada_task_ptid,
+ (ptid_t (*) (long, long))
+ default_get_ada_task_ptid);
#undef de_fault

/* Finally, position the target-stack beneath the squashed
diff -r b2b21339d264 gdb/ada-lang.h
--- a/gdb/ada-lang.h Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/ada-lang.h Mon Sep 22 15:50:06 2008 -0700
@@ -196,46 +196,37 @@ enum ada_renaming_category

/* Ada task structures. */

-/* Ada task control block, as defined in the GNAT runt-time library. */
+struct ada_task_info
+{
+ /* The PTID of the thread that this task runs on. This ptid is computed
+ in a target-dependent way from the associated Task Control Block. */
+ ptid_t ptid;

-struct task_control_block
-{
- char state;
+ /* The ID of the task. */
+ CORE_ADDR task_id;
+
+ /* The name of the task. */
+ char name[257];
+
+ /* The current state of the task. */
+ int state;
+
+ /* The priority associated to the task. */
+ int priority;
+
+ /* If non-zero, the task ID of the parent task. */
CORE_ADDR parent;
- int priority;
- char image [32];
- int image_len; /* This field is not always present in the ATCB. */
- CORE_ADDR call;
- CORE_ADDR thread;
- CORE_ADDR lwp; /* This field is not always present in the ATCB. */

- /* If the task is waiting on a task entry, this field contains the
- task_id of the other task. */
+ /* If the task is waiting on a task entry, this field contains
+ the ID of the other task. Zero otherwise. */
CORE_ADDR called_task;
+
+ /* If the task is accepting a rendezvous with another task, this field
+ contains the ID of the calling task. Zero otherwise. */
+ CORE_ADDR caller_task;
};

-struct task_ptid
-{
- int pid; /* The Process id */
- long lwp; /* The Light Weight Process id */
- long tid; /* The Thread id */
-};
-typedef struct task_ptid task_ptid_t;
-
-struct task_entry
-{
- CORE_ADDR task_id;
- struct task_control_block atcb;
- int task_num;
- int known_tasks_index;
- struct task_entry *next_task;
- task_ptid_t task_ptid;
- int stack_per;
-};
-
-/* task entry list. */
-extern struct task_entry *task_list;
-
+int ada_task_is_alive (struct ada_task_info *task);

/* Assuming V points to an array of S objects, make sure that it contains at
least M objects, updating V and S as necessary. */
@@ -465,6 +456,8 @@ extern enum ada_renaming_category ada_pa
const char **,
int *, const char **);

+extern void ada_find_printable_frame (struct frame_info *fi);
+
extern char *ada_breakpoint_rewrite (char *, int *);

extern char *ada_main_name (void);
@@ -473,9 +466,9 @@ extern char *ada_main_name (void);

extern int valid_task_id (int);

-extern void init_task_list (void);
-
-extern int ada_is_exception_breakpoint (bpstat bs);
+typedef void (ada_task_list_iterator_ftype) (struct ada_task_info *task);
+extern void iterate_over_live_ada_tasks
+ (ada_task_list_iterator_ftype *iterator);

extern void ada_adjust_exception_stop (bpstat bs);

@@ -491,7 +484,7 @@ extern void ada_print_exception_breakpoi

extern void ada_reset_thread_registers (void);

-extern int ada_build_task_list (void);
+extern int ada_build_task_list (int warn_if_null);

extern int ada_exception_catchpoint_p (struct breakpoint *b);

diff -r b2b21339d264 gdb/ada-lang.c
--- a/gdb/ada-lang.c Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/ada-lang.c Mon Sep 22 15:50:06 2008 -0700
@@ -9852,7 +9852,7 @@ is_known_support_routine (struct frame_i
/* Find the first frame that contains debugging information and that is not
part of the Ada run-time, starting from FI and moving upward. */

-static void
+void
ada_find_printable_frame (struct frame_info *fi)
{
for (; fi != NULL; fi = get_prev_frame (fi))
diff -r b2b21339d264 gdb/ada-tasks.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/gdb/ada-tasks.c Mon Sep 22 15:50:06 2008 -0700
@@ -0,0 +1,992 @@
+/* Copyright (C) 1992, 1993, 1994, 1997, 1998, 1999, 2000, 2003, 2004,
+ 2005, 2007, 2008 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "defs.h"
+#include "observer.h"
+#include "gdbcmd.h"
+#include "target.h"
+#include "ada-lang.h"
+#include "gdbcore.h"
+#include "inferior.h"
+#include "gdbthread.h"
+
+/* The name of the array in the GNAT runtime where the Ada Task Control
+ Block of each task is stored. */
+#define KNOWN_TASKS_NAME "system__tasking__debug__known_tasks"
+
+/* The maximum number of tasks known to the Ada runtime */
+static const int MAX_NUMBER_OF_KNOWN_TASKS = 1000;
+
+enum task_states
+{
+ Unactivated,
+ Runnable,
+ Terminated,
+ Activator_Sleep,
+ Acceptor_Sleep,
+ Entry_Caller_Sleep,
+ Async_Select_Sleep,
+ Delay_Sleep,
+ Master_Completion_Sleep,
+ Master_Phase_2_Sleep,
+ Interrupt_Server_Idle_Sleep,
+ Interrupt_Server_Blocked_Interrupt_Sleep,
+ Timer_Server_Sleep,
+ AST_Server_Sleep,
+ Asynchronous_Hold,
+ Interrupt_Server_Blocked_On_Event_Flag
+};
+
+/* A short description corresponding to each possible task state. */
+static char *task_states[] = {
+ "Unactivated",
+ "Runnable",
+ "Terminated",
+ "Child Activation Wait",
+ "Accept Statement",
+ "Waiting on entry call",
+ "Async Select Wait",
+ "Delay Sleep",
+ "Child Termination Wait",
+ "Wait Child in Term Alt",
+ "",
+ "",
+ "",
+ "",
+ "Asynchronous Hold"
+ ""
+};
+
+/* A longer description corresponding to each possible task state. */
+static char *long_task_states[] = {
+ "Unactivated",
+ "Runnable",
+ "Terminated",
+ "Waiting for child activation",
+ "Blocked in accept statement",
+ "Waiting on entry call",
+ "Asynchronous Selective Wait",
+ "Delay Sleep",
+ "Waiting for children termination",
+ "Waiting for children in terminate alternative",
+ "",
+ "",
+ "",
+ "",
+ "Asynchronous Hold"
+ ""
+};
+
+/* The index of certain important fields in the Ada Task Control Block
+ record and sub-records. */
+
+struct tcb_fieldnos
+{
+ /* Fields in record Ada_Task_Control_Block. */
+ int common;
+ int entry_calls;
+ int atc_nesting_level;
+
+ /* Fields in record Common_ATCB. */
+ int state;
+ int parent;
+ int priority;
+ int image;
+ int image_len; /* This field may be missing. */
+ int call;
+ int ll;
+
+ /* Fields in Task_Primitives.Private_Data. */
+ int ll_thread;
+ int ll_lwp; /* This field may be missing. */
+
+ /* Fields in Common_ATCB.Call.all. */
+ int call_self;
+};
+
+/* The type description for the ATCB record and subrecords, and
+ the associated tcb_fieldnos. For efficiency reasons, these are made
+ static globals so that we can compute them only once the first time
+ and reuse them later. Set to NULL if the types haven't been computed
+ yet, or if they may be obsolete (for instance after having loaded
+ a new binary). */
+
+static struct type *atcb_type = NULL;
+static struct type *atcb_common_type = NULL;
+static struct type *atcb_ll_type = NULL;
+static struct type *atcb_call_type = NULL;
+static struct tcb_fieldnos fieldno;
+
+/* Set to 1 when the cached address of System.Tasking.Debug.Known_Tasks
+ might be stale and so needs to be recomputed. */
+static int ada_tasks_check_symbol_table = 1;
+
+/* The list of Ada tasks.
+
+ Note: To each task we associate a number that the user can use to
+ reference it - this number is printed beside each task in the tasks
+ info listing displayed by "info tasks". This number is equal to
+ its index in the vector + 1. Reciprocally, to compute the index
+ of a task in the vector, we need to substract 1 from its number. */
+typedef struct ada_task_info ada_task_info_s;
+DEF_VEC_O(ada_task_info_s);
+static VEC(ada_task_info_s) *task_list = NULL;
+
+/* When non-zero, this flag indicates that the current task_list
+ is obsolete, and should be recomputed before it is accessed. */
+static int stale_task_list_p = 1;
+
+/* Return the task number of the task whose ptid is PTID, or zero
+ if the task could not be found. */
+
+int
+ada_get_task_number (ptid_t ptid)
+{
+ int i;
+
+ for (i=0; i < VEC_length (ada_task_info_s, task_list); i++)
+ if (ptid_equal (VEC_index (ada_task_info_s, task_list, i)->ptid, ptid))
+ return i + 1;
+
+ return 0; /* No matching task found. */
+}
+
+/* Return the task number of the task that matches TASK_ID, or zero
+ if the task could not be found. */
+
+static int
+get_task_number_from_id (CORE_ADDR task_id)
+{
+ int i;
+
+ for (i = 0; i < VEC_length (ada_task_info_s, task_list); i++)
+ {
+ struct ada_task_info *task_info =
+ VEC_index (ada_task_info_s, task_list, i);
+
+ if (task_info->task_id == task_id)
+ return i + 1;
+ }
+
+ /* Task not found. Return 0. */
+ return 0;
+}
+
+/* Return non-zero if TASK_NUM is a valid task number. */
+
+int
+valid_task_id (int task_num)
+{
+ return (task_num > 0
+ && task_num <= VEC_length (ada_task_info_s, task_list));
+}
+
+/* Return the task info associated to the Environment Task.
+ This function assumes that the inferior does in fact use tasking. */
+
+struct ada_task_info *
+ada_get_environment_task (void)
+{
+ ada_build_task_list (0);
+ gdb_assert (VEC_length (ada_task_info_s, task_list) > 0);
+
+ /* We use a little bit of insider knowledge to determine which task
+ is the Environment Task: We know that this task is created first,
+ and thus should always be task #1, which is at index 0 of the
+ TASK_LIST. */
+ return (VEC_index (ada_task_info_s, task_list, 0));
+}
+
+void
+iterate_over_live_ada_tasks (ada_task_list_iterator_ftype *iterator)
+{
+ int i, nb_tasks;
+ struct ada_task_info *task;
+
+ ada_build_task_list (0);
+ nb_tasks = VEC_length (ada_task_info_s, task_list);
+
+ for (i = 0; i < nb_tasks; i++)
+ {
+ task = VEC_index (ada_task_info_s, task_list, i);
+ if (!ada_task_is_alive (task))
+ continue;
+ iterator (task);
+ }
+}
+
+/* Extract the contents of the value as a string whose length is LENGTH,
+ and store the result in DEST. */
+
+static void
+value_as_string (char *dest, struct value *val, int length)
+{
+ memcpy (dest, value_contents (val), length);
+ dest[length] = '\0';
+}
+
+/* Extract the string image from the fat string corresponding to VAL,
+ and store it in DEST. If the string length is greater than MAX_LEN,
+ then truncate the result to the first MAX_LEN characters of the fat
+ string. */
+
+static void
+read_fat_string_value (char *dest, struct value *val, int max_len)
+{
+ struct value *array_val;
+ struct value *bounds_val;
+ int len;
+
+ /* The following variables are made static to avoid recomputing them
+ each time this function is called. */
+ static int initialize_fieldnos = 1;
+ static int array_fieldno;
+ static int bounds_fieldno;
+ static int upper_bound_fieldno;
+
+ /* Get the index of the fields that we will need to read in order
+ to extract the string from the fat string. */
+ if (initialize_fieldnos)
+ {
+ struct type *type = value_type (val);
+ struct type *bounds_type;
+
+ array_fieldno = ada_get_field_index (type, "P_ARRAY", 0);
+ bounds_fieldno = ada_get_field_index (type, "P_BOUNDS", 0);
+
+ bounds_type = TYPE_FIELD_TYPE (type, bounds_fieldno);
+ if (TYPE_CODE (bounds_type) == TYPE_CODE_PTR)
+ bounds_type = TYPE_TARGET_TYPE (bounds_type);
+ if (TYPE_CODE (bounds_type) != TYPE_CODE_STRUCT)
+ error (_("Unknown task name format. Aborting"));
+ upper_bound_fieldno = ada_get_field_index (bounds_type, "UB0", 0);
+
+ initialize_fieldnos = 0;
+ }
+
+ /* Get the size of the task image by checking the value of the bounds.
+ The lower bound is always 1, so we only need to read the upper bound. */
+ bounds_val = value_ind (value_field (val, bounds_fieldno));
+ len = value_as_long (value_field (bounds_val, upper_bound_fieldno));
+
+ /* Make sure that we do not read more than max_len characters... */
+ if (len > max_len)
+ len = max_len;
+
+ /* Extract LEN characters from the fat string. */
+ array_val = value_ind (value_field (val, array_fieldno));
+ read_memory (VALUE_ADDRESS (array_val), dest, len);
+
+ /* Add the NUL character to close the string. */
+ dest[len] = '\0';
+}
+
+/* Return the address of the Known_Tasks array maintained in
+ the Ada Runtime. Return NULL if the array could not be found,
+ meaning that the inferior program probably does not use tasking.
+
+ In order to provide a fast response time, this function caches
+ the Known_Tasks array address after the lookup during the first
+ call. Subsequent calls will simply return this cached address. */
+
+static CORE_ADDR
+get_known_tasks_addr (void)
+{
+ static CORE_ADDR known_tasks_addr = 0;
+
+ if (ada_tasks_check_symbol_table)
+ {
+ struct symbol *sym;
+ struct minimal_symbol *msym;
+
+ msym = lookup_minimal_symbol (KNOWN_TASKS_NAME, NULL, NULL);
+ if (msym != NULL)
+ known_tasks_addr = SYMBOL_VALUE_ADDRESS (msym);
+ else
+ {
+ if (target_lookup_symbol (KNOWN_TASKS_NAME, &known_tasks_addr) != 0)
+ return 0;
+ }
+
+ /* FIXME: brobecker 2003-03-05: Here would be a much better place
+ to attach the ada-tasks observers, instead of doing this
+ unconditionaly in _initialize_tasks. This would avoid an
+ unecessary notification when the inferior does not use tasking
+ or as long as the user does not use the ada-tasks commands.
+ Unfortunately, this is not possible for the moment: the current
+ code resets ada__tasks_check_symbol_table back to 1 whenever
+ symbols for a new program are being loaded. If we place the
+ observers intialization here, we will end up adding new observers
+ everytime we do the check for Ada tasking-related symbols
+ above. This would currently have benign effects, but is still
+ undesirable. The cleanest approach is probably to create a new
+ observer to notify us when the user is debugging a new program.
+ We would then reset ada__tasks_check_symbol_table back to 1
+ during the notification, but also detach all observers.
+ BTW: observers are probably not reentrant, so detaching during
+ a notification may not be the safest thing to do... Sigh...
+ But creating the new observer would be a good idea in any case,
+ since this allow us to make ada__tasks_check_symbol_table
+ static, which is a good bonus. */
+ ada_tasks_check_symbol_table = 0;
+ }
+
+ return known_tasks_addr;
+}
+
+/* Get from the debugging information the type description of all types
+ related to the Ada Task Control Block that will be needed in order to
+ read the list of known tasks in the Ada runtime. Also return the
+ associated ATCB_FIELDNOS.
+
+ Error handling: Any data missing from the debugging info will cause
+ an error to be raised, and none of the return values to be set.
+ Users of this function can depend on the fact that all or none of the
+ return values will be set. */
+
+static void
+get_tcb_types_info (struct type **atcb_type,
+ struct type **atcb_common_type,
+ struct type **atcb_ll_type,
+ struct type **atcb_call_type,
+ struct tcb_fieldnos *atcb_fieldnos)
+{
+ struct type *type;
+ struct type *common_type;
+ struct type *ll_type;
+ struct type *call_type;
+ struct tcb_fieldnos fieldnos;
+
+ const char *atcb_name = "system__tasking__ada_task_control_block___XVE";
+ const char *atcb_name_fixed = "system__tasking__ada_task_control_block";
+ const char *common_atcb_name = "system__tasking__common_atcb";
+ const char *private_data_name = "system__task_primitives__private_data";
+ const char *entry_call_record_name = "system__tasking__entry_call_record";
+
+ struct symbol *atcb_sym =
+ lookup_symbol (atcb_name, NULL, VAR_DOMAIN, NULL);
+ const struct symbol *common_atcb_sym =
+ lookup_symbol (common_atcb_name, NULL, VAR_DOMAIN, NULL);
+ const struct symbol *private_data_sym =
+ lookup_symbol (private_data_name, NULL, VAR_DOMAIN, NULL);
+ const struct symbol *entry_call_record_sym =
+ lookup_symbol (entry_call_record_name, NULL, VAR_DOMAIN, NULL);
+
+ if (atcb_sym == NULL || atcb_sym->type == NULL)
+ {
+ /* In Ravenscar run-time libs, the ATCB does not have a dynamic
+ size, so the symbol name differs. */
+ atcb_sym = lookup_symbol (atcb_name_fixed, NULL, VAR_DOMAIN, NULL);
+
+ if (atcb_sym == NULL || atcb_sym->type == NULL)
+ error (_("Cannot find Ada_Task_Control_Block type. Aborting"));
+
+ type = atcb_sym->type;
+ }
+ else
+ {
+ /* Get a static representation of the type record
+ Ada_Task_Control_Block. */
+ type = atcb_sym->type;
+ type = ada_template_to_fixed_record_type_1 (type, NULL, 0, NULL, 0);
+ }
+
+ if (common_atcb_sym == NULL || common_atcb_sym->type == NULL)
+ error (_("Cannot find Common_ATCB type. Aborting"));
+ if (private_data_sym == NULL || private_data_sym->type == NULL)
+ error (_("Cannot find Private_Data type. Aborting"));
+ if (entry_call_record_sym == NULL || entry_call_record_sym->type == NULL)
+ error (_("Cannot find Entry_Call_Record type. Aborting"));
+
+ /* Get the type for Ada_Task_Control_Block.Common. */
+ common_type = common_atcb_sym->type;
+
+ /* Get the type for Ada_Task_Control_Bloc.Common.Call.LL. */
+ ll_type = private_data_sym->type;
+
+ /* Get the type for Common_ATCB.Call.all. */
+ call_type = entry_call_record_sym->type;
+
+ /* Get the field indices. */
+ fieldnos.common = ada_get_field_index (type, "common", 0);
+ fieldnos.entry_calls = ada_get_field_index (type, "entry_calls", 1);
+ fieldnos.atc_nesting_level =
+ ada_get_field_index (type, "atc_nesting_level", 1);
+ fieldnos.state = ada_get_field_index (common_type, "state", 0);
+ fieldnos.parent = ada_get_field_index (common_type, "parent", 1);
+ fieldnos.priority = ada_get_field_index (common_type, "base_priority", 0);
+ fieldnos.image = ada_get_field_index (common_type, "task_image", 1);
+ fieldnos.image_len = ada_get_field_index (common_type, "task_image_len", 1);
+ fieldnos.call = ada_get_field_index (common_type, "call", 1);
+ fieldnos.ll = ada_get_field_index (common_type, "ll", 0);
+ fieldnos.ll_thread = ada_get_field_index (ll_type, "thread", 0);
+ fieldnos.ll_lwp = ada_get_field_index (ll_type, "lwp", 1);
+ fieldnos.call_self = ada_get_field_index (call_type, "self", 0);
+
+ /* On certain platforms such as x86-windows, the "lwp" field has been
+ named "thread_id". This field will likely be renamed in the future,
+ but we need to support both possibilities to avoid an unnecessary
+ dependency on a recent compiler. We therefore try locating the
+ "thread_id" field in place of the "lwp" field if we did not find
+ the latter. */
+ if (fieldnos.ll_lwp < 0)
+ fieldnos.ll_lwp = ada_get_field_index (ll_type, "thread_id", 1);
+
+ /* Set all the out parameters all at once, now that we are certain
+ that there are no potential error() anymore. */
+ *atcb_type = type;
+ *atcb_common_type = common_type;
+ *atcb_ll_type = ll_type;
+ *atcb_call_type = call_type;
+ *atcb_fieldnos = fieldnos;
+}
+
+/* Build the PTID of the task from its COMMON_VALUE, which is the "Common"
+ component of its ATCB record. This PTID needs to match the PTID used
+ by the thread layer. */
+
+static ptid_t
+ptid_from_atcb_common (struct value *common_value)
+{
+ long thread = 0;
+ CORE_ADDR lwp = 0;
+ struct value *ll_value;
+ ptid_t ptid;
+
+ ll_value = value_field (common_value, fieldno.ll);
+
+ if (fieldno.ll_lwp >= 0)
+ lwp = value_as_address (value_field (ll_value, fieldno.ll_lwp));
+ thread = value_as_long (value_field (ll_value, fieldno.ll_thread));
+
+ ptid = target_get_ada_task_ptid (lwp, thread);
+
+ return ptid;
+}
+
+/* Read the ATCB data of a given task given its TASK_ID (which is in practice
+ the address of its assocated ATCB record), and store the result inside
+ TASK_INFO. */
+
+static void
+read_atcb (CORE_ADDR task_id, struct ada_task_info *task_info)
+{
+ struct value *tcb_value;
+ struct value *common_value;
+ struct value *atc_nesting_level_value;
+ struct value *entry_calls_value;
+ struct value *entry_calls_value_element;
+ int called_task_fieldno = -1;
+ const char ravenscar_task_name[] = "Ravenscar task";
+
+ if (atcb_type == NULL)
+ get_tcb_types_info (&atcb_type, &atcb_common_type, &atcb_ll_type,
+ &atcb_call_type, &fieldno);
+
+ tcb_value = value_from_contents_and_address (atcb_type, NULL, task_id);
+ common_value = value_field (tcb_value, fieldno.common);
+
+ /* Fill in the task_id. */
+
+ task_info->task_id = task_id;
+
+ /* Compute the name of the task.
+
+ Depending on the GNAT version used, the task image is either a fat
+ string, or a thin array of characters. Older versions of GNAT used
+ to use fat strings, and therefore did not need an extra field in
+ the ATCB to store the string length. For efficiency reasons, newer
+ versions of GNAT replaced the fat string by a static buffer, but this
+ also required the addition of a new field named "Image_Len" containing
+ the length of the task name. The method used to extract the task name
+ is selected depending on the existence of this field.
+
+ In some run-time libs (e.g. Ravenscar), the name is not in the ATCB;
+ we may want to get it from the first user frame of the stack. For now,
+ we just give a dummy name. */
+
+ if (fieldno.image_len == -1)
+ {
+ if (fieldno.image >= 0)
+ read_fat_string_value (task_info->name,
+ value_field (common_value, fieldno.image),
+ sizeof (task_info->name) - 1);
+ else
+ strcpy (task_info->name, ravenscar_task_name);
+ }
+ else
+ {
+ int len = value_as_long (value_field (common_value, fieldno.image_len));
+
+ value_as_string (task_info->name,
+ value_field (common_value, fieldno.image), len);
+ }
+
+ /* Compute the task state and priority. */
+
+ task_info->state = value_as_long (value_field (common_value, fieldno.state));
+ task_info->priority =
+ value_as_long (value_field (common_value, fieldno.priority));
+
+ /* If the ATCB contains some information about the parent task,
+ then compute it as well. Otherwise, zero. */
+
+ if (fieldno.parent >= 0)
+ task_info->parent =
+ value_as_address (value_field (common_value, fieldno.parent));
+ else
+ task_info->parent = 0;
+
+
+ /* If the ATCB contains some information about entry calls, then
+ compute the "called_task" as well. Otherwise, zero. */
+
+ if (fieldno.atc_nesting_level > 0 && fieldno.entry_calls > 0)
+ {
+ /* Let My_ATCB be the Ada task control block of a task calling the
+ entry of another task; then the Task_Id of the called task is
+ in My_ATCB.Entry_Calls (My_ATCB.ATC_Nesting_Level).Called_Task. */
+ atc_nesting_level_value = value_field (tcb_value,
+ fieldno.atc_nesting_level);
+ entry_calls_value =
+ ada_coerce_to_simple_array_ptr (value_field (tcb_value,
+ fieldno.entry_calls));
+ entry_calls_value_element =
+ value_subscript (entry_calls_value, atc_nesting_level_value);
+ called_task_fieldno =
+ ada_get_field_index (value_type (entry_calls_value_element),
+ "called_task", 0);
+ task_info->called_task =
+ value_as_address (value_field (entry_calls_value_element,
+ called_task_fieldno));
+ }
+ else
+ {
+ task_info->called_task = 0;
+ }
+
+ /* If the ATCB cotnains some information about RV callers,
+ then compute the "caller_task". Otherwise, zero. */
+
+ task_info->caller_task = 0;
+ if (fieldno.call >= 0)
+ {
+ /* Get the ID of the caller task from Common_ATCB.Call.all.Self.
+ If Common_ATCB.Call is null, then there is no caller. */
+ const CORE_ADDR call =
+ value_as_address (value_field (common_value, fieldno.call));
+ struct value *call_val;
+
+ if (call != 0)
+ {
+ call_val =
+ value_from_contents_and_address (atcb_call_type, NULL, call);
+ task_info->caller_task =
+ value_as_address (value_field (call_val, fieldno.call_self));
+ }
+ }
+
+ /* And finally, compute the task ptid. */
+
+ if (ada_task_is_alive (task_info))
+ task_info->ptid = ptid_from_atcb_common (common_value);
+ else
+ task_info->ptid = null_ptid;
+}
+
+/* Read the ATCB info of the given task (identified by TASK_ID), and
+ add the result to the TASK_LIST. */
+
+static void
+add_ada_task (CORE_ADDR task_id)
+{
+ struct ada_task_info task_info;
+
+ read_atcb (task_id, &task_info);
+ VEC_safe_push (ada_task_info_s, task_list, &task_info);
+}
+
+/* Read the Known_Tasks array from the inferior memory, and store
+ it in TASK_LIST. Return non-zero upon success. */
+
+static int
+read_known_tasks_array (void)
+{
+ const int target_ptr_byte =
+ gdbarch_ptr_bit (current_gdbarch) / TARGET_CHAR_BIT;
+ const CORE_ADDR known_tasks_addr = get_known_tasks_addr ();
+ const int known_tasks_size = target_ptr_byte * MAX_NUMBER_OF_KNOWN_TASKS;
+ gdb_byte *known_tasks = alloca (known_tasks_size);
+ int i;
+
+ /* Step 1: Clear the current list, if necessary. */
+ VEC_truncate (ada_task_info_s, task_list, 0);
+
+ /* If the application does not use task, then no more needs to be done.
+ It is important to have the task list cleared (see above) before we
+ return, as we don't want a stale task list to be used... This can
+ happen for instance when debugging a non-multitasking program after
+ having debugged a multitasking one. */
+ if (known_tasks_addr == 0)
+ return 0;
+
+ /* Step 2: Build a new list by reading the ATCBs from the Known_Tasks
+ array in the Ada runtime. */
+ read_memory (known_tasks_addr, known_tasks, known_tasks_size);
+ for (i = 0; i < MAX_NUMBER_OF_KNOWN_TASKS; i++)
+ {
+ struct type *data_ptr_type =
+ builtin_type (current_gdbarch)->builtin_data_ptr;
+ CORE_ADDR task_id =
+ extract_typed_address (known_tasks + i * target_ptr_byte,
+ data_ptr_type);
+
+ if (task_id != 0)
+ add_ada_task (task_id);
+ }
+
+ /* Step 3: Unset stale_task_list_p, to avoid re-reading the Known_Tasks
+ array unless needed. Then report a success. */
+ stale_task_list_p = 0;
+
+ return 1;
+}
+
+/* Builds the task_list by reading the Known_Tasks array from
+ the inferior. Prints an appropriate message and returns non-zero
+ if it failed to build this list. */
+
+int
+ada_build_task_list (int warn_if_null)
+{
+ if (!target_has_stack)
+ error (_("Cannot inspect Ada tasks when program is not running"));
+
+ if (stale_task_list_p)
+ read_known_tasks_array ();
+
+ if (task_list == NULL)
+ {
+ if (warn_if_null)
+ printf_filtered (_("Your application does not use any Ada task.\n"));
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Return non-zero iff the task STATE corresponds to a non-terminated
+ task state. */
+
+int
+ada_task_is_alive (struct ada_task_info *task_info)
+{
+ return (task_info->state != Terminated);
+}
+
+/* Print a one-line description of the task whose number is TASKNO.
+ The formatting should fit the "info tasks" array. */
+
+static void
+short_task_info (int taskno)
+{
+ const struct ada_task_info *const task_info =
+ VEC_index (ada_task_info_s, task_list, taskno - 1);
+ int active_task_p;
+
+ gdb_assert (task_info != NULL);
+
+ /* Print a star if this task is the current task (or the task currently
+ selected). */
+
+ active_task_p = ptid_equal (task_info->ptid, inferior_ptid);
+ if (active_task_p)
+ printf_filtered ("*");
+ else
+ printf_filtered (" ");
+
+ /* Print the task number. */
+ printf_filtered ("%3d", taskno);
+
+ /* Print the Task ID. */
+ printf_filtered (" %9lx", (long) task_info->task_id);
+
+ /* Print the Task ID of the task parent. */
+ printf_filtered (" %4d", get_task_number_from_id (task_info->parent));
+
+ /* Print the base priority of the task. */
+ printf_filtered (" %3d", task_info->priority);
+
+ /* Print the task current state. */
+ if (task_info->caller_task)
+ printf_filtered (_(" Accepting RV with %-4d"),
+ get_task_number_from_id (task_info->caller_task));
+ else if (task_info->state == Entry_Caller_Sleep && task_info->called_task)
+ printf_filtered (_(" Waiting on RV with %-3d"),
+ get_task_number_from_id (task_info->called_task));
+ else if (task_info->state == Runnable && active_task_p)
+ /* Replace "Runnable" by "Running" since this is the active task. */
+ printf_filtered (" %-22s", "Running");
+ else
+ printf_filtered (" %-22s", task_states[task_info->state]);
+
+ /* Finally, print the task name. */
+ if (task_info->name[0] != '\0')
+ printf_filtered (" %s\n", task_info->name);
+ else
+ printf_filtered (_(" <no name>\n"));
+}
+
+/* Print a list containing a short description of all Ada tasks. */
+/* FIXME: Shouldn't we be using ui_out??? */
+
+static void
+info_tasks (int from_tty)
+{
+ int taskno;
+ const int nb_tasks = VEC_length (ada_task_info_s, task_list);
+
+ printf_filtered (_(" ID TID P-ID Pri State Name\n"));
+
+ for (taskno = 1; taskno <= nb_tasks; taskno++)
+ short_task_info (taskno);
+}
+
+/* Print a detailed description of the Ada task whose ID is TASKNO_STR. */
+
+static void
+info_task (char *taskno_str, int from_tty)
+{
+ const int taskno = value_as_long (parse_and_eval (taskno_str));
+ struct ada_task_info *task_info;
+ int parent_taskno = 0;
+
+ if (taskno <= 0 || taskno > VEC_length (ada_task_info_s, task_list))
+ error (_("Task ID %d not known. Use the \"info tasks\" command to\n"
+ "see the IDs of currently known tasks"), taskno);
+ task_info = VEC_index (ada_task_info_s, task_list, taskno - 1);
+
+ /* Print the Ada task ID. */
+ printf_filtered (_("Ada Task: %s\n"), paddr_nz (task_info->task_id));
+
+ /* Print the name of the task. */
+ if (task_info->name[0] != '\0')
+ printf_filtered (_("Name: %s\n"), task_info->name);
+ else
+ printf_filtered (_("<no name>\n"));
+
+ /* Print the TID and LWP. */
+ printf_filtered (_("Thread: %#lx\n"), ptid_get_tid (task_info->ptid));
+ printf_filtered (_("LWP: %#lx\n"), ptid_get_lwp (task_info->ptid));
+
+ /* Print who is the parent (if any). */
+ if (task_info->parent != 0)
+ parent_taskno = get_task_number_from_id (task_info->parent);
+ if (parent_taskno)
+ {
+ struct ada_task_info *parent =
+ VEC_index (ada_task_info_s, task_list, parent_taskno - 1);
+
+ printf_filtered (_("Parent: %d"), parent_taskno);
+ if (parent->name[0] != '\0')
+ printf_filtered (" (%s)", parent->name);
+ printf_filtered ("\n");
+ }
+ else
+ printf_filtered (_("No parent\n"));
+
+ /* Print the base priority. */
+ printf_filtered (_("Base Priority: %d\n"), task_info->priority);
+
+ /* print the task current state. */
+ {
+ int target_taskno = 0;
+
+ if (task_info->caller_task)
+ {
+ target_taskno = get_task_number_from_id (task_info->caller_task);
+ printf_filtered (_("State: Accepting rendezvous with %d"),
+ target_taskno);
+ }
+ else if (task_info->state == Entry_Caller_Sleep && task_info->called_task)
+ {
+ target_taskno = get_task_number_from_id (task_info->called_task);
+ printf_filtered (_("State: Waiting on task %d's entry"),
+ target_taskno);
+ }
+ else
+ printf_filtered ("State: %s", long_task_states[task_info->state]);
+
+ if (target_taskno)
+ {
+ struct ada_task_info *target_task_info =
+ VEC_index (ada_task_info_s, task_list, target_taskno - 1);
+
+ if (target_task_info->name[0] != '\0')
+ printf_filtered (" (%s)", target_task_info->name);
+ }
+
+ printf_filtered ("\n");
+ }
+}
+
+/* If ARG is empty or null, then print a list of all Ada tasks.
+ Otherwise, print detailed information about the task whose ID
+ is ARG.
+
+ Does nothing if the program doesn't use Ada tasking. */
+
+static void
+info_tasks_command (char *arg, int from_tty)
+{
+ const int task_list_built = ada_build_task_list (1);
+
+ if (!task_list_built)
+ return;
+
+ if (arg == NULL || *arg == '\0')
+ info_tasks (from_tty);
+ else
+ info_task (arg, from_tty);
+}
+
+/* Print a message telling the user id of the current task.
+ This function assumes that tasking is in use in the inferior. */
+
+static void
+display_current_task_id (void)
+{
+ const int current_task = ada_get_task_number (inferior_ptid);
+
+ if (current_task == 0)
+ printf_filtered (_("[Current task is unknown]\n"));
+ else
+ printf_filtered (_("[Current task is %d]\n"), current_task);
+}
+
+/* Parse and evaluate TIDSTR into a task id, and try to switch to
+ that task. Print an error message if the task switch failed. */
+
+static void
+task_command_1 (char *taskno_str, int from_tty)
+{
+ const int taskno = value_as_long (parse_and_eval (taskno_str));
+ struct ada_task_info *task_info;
+
+ if (taskno <= 0 || taskno > VEC_length (ada_task_info_s, task_list))
+ error (_("Task ID %d not known. Use the \"info tasks\" command to\n"
+ "see the IDs of currently known tasks"), taskno);
+ task_info = VEC_index (ada_task_info_s, task_list, taskno - 1);
+
+ if (!ada_task_is_alive (task_info))
+ error (_("Cannot switch to task %d: Task is no longer running"), taskno);
+
+ switch_to_thread (task_info->ptid);
+ ada_find_printable_frame (get_selected_frame (NULL));
+ printf_filtered (_("[Switching to task %d]\n"), taskno);
+ print_stack_frame (get_selected_frame (NULL),
+ frame_relative_level (get_selected_frame (NULL)), 1);
+}
+
+
+/* Print the ID of the current task if TASKNO_STR is empty or NULL.
+ Otherwise, switch to the task indicated by TASKNO_STR. */
+
+static void
+task_command (char *taskno_str, int from_tty)
+{
+ const int task_list_built = ada_build_task_list (1);
+
+ if (!task_list_built)
+ return;
+
+ if (taskno_str == NULL || taskno_str[0] == '\0')
+ display_current_task_id ();
+ else
+ {
+ /* Task switching in core files doesn't work, either because:
+ 1. Thread support is not implemented with core files
+ 2. Thread support is implemented, but the thread IDs created
+ after having read the core file are not the same as the ones
+ that were used during the program life, before the crash.
+ As a consequence, there is no longer a way for the debugger
+ to find the associated thead ID of any given Ada task.
+ So, instead of attempting a task switch without giving the user
+ any clue as to what might have happened, just error-out with
+ a message explaining that this feature is not supported. */
+ if (!target_has_execution)
+ error (_("\
+Task switching not supported when debugging from core files\n\
+(use thread support instead)"));
+ task_command_1 (taskno_str, from_tty);
+ }
+}
+
+/* Indicate that the task list may have changed, so invalidate the cache. */
+
+void
+ada_task_list_changed (void)
+{
+ stale_task_list_p = 1;
+}
+
+/* The 'normal_stop' observer notification callback. */
+
+static void
+ada_normal_stop_observer (struct bpstats *unused_args)
+{
+ /* The inferior has been resumed, and just stopped. This means that
+ our task_list needs to be recomputed before it can be used again. */
+ ada_task_list_changed ();
+}
+
+/* A routine to be called when the objfiles have changed. */
+
+void
+ada_new_objfile_observer (struct objfile *objfile)
+{
+ /* Invalidate all cached data that were extracted from an objfile. */
+
+ atcb_type = NULL;
+ atcb_common_type = NULL;
+ atcb_ll_type = NULL;
+ atcb_call_type = NULL;
+
+ ada_tasks_check_symbol_table = 1;
+}
+
+void
+_initialize_tasks (void)
+{
+ /* Attach various observers. */
+ observer_attach_normal_stop (ada_normal_stop_observer);
+ observer_attach_new_objfile (ada_new_objfile_observer);
+
+ /* Some new commands provided by this module. */
+ add_info ("tasks", info_tasks_command,
+ _("\
+Without argument: list all known Ada tasks, with status information.\n\
+info tasks N: print detailed information of task N."));
+
+ add_cmd ("task", class_run, task_command,
+ _("\
+Without argument: print the current task ID.\n\
+task N: Use this command to switch to task N."),
+ &cmdlist);
+}
+
diff -r b2b21339d264 gdb/Makefile.in
--- a/gdb/Makefile.in Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/Makefile.in Mon Sep 22 15:50:06 2008 -0700
@@ -609,7 +609,7 @@ TARGET_FLAGS_TO_PASS = \
# Links made at configuration time should not be specified here, since
# SFILES is used in building the distribution archive.

-SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c \
+SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
addrmap.c \
auxv.c ax-general.c ax-gdb.c \
bcache.c \
@@ -782,6 +782,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $
dwarf2read.o mipsread.o stabsread.o corefile.o \
dwarf2expr.o dwarf2loc.o dwarf2-frame.o \
ada-lang.o c-lang.o f-lang.o objc-lang.o \
+ ada-tasks.o \
ui-out.o cli-out.o \
varobj.o vec.o wrapper.o \
jv-lang.o jv-valprint.o jv-typeprint.o \
diff -r b2b21339d264 gdb/linux-thread-db.c
--- a/gdb/linux-thread-db.c Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/linux-thread-db.c Mon Sep 22 15:50:06 2008 -0700
@@ -1143,6 +1143,33 @@ thread_db_get_thread_local_address (ptid
_("TLS not supported on this target"));
}

+/* Callback routine used to find a thread based on the TID part of
+ its PTID. */
+
+static int
+thread_db_find_thread_from_tid (struct thread_info *thread, void *data)
+{
+ long *tid = (long *) data;
+
+ if (thread->private->tid == *tid)
+ return 1;
+
+ return 0;
+}
+
+static ptid_t
+thread_db_get_ada_task_ptid (long lwp, long thread)
+{
+ struct thread_info *thread_info;
+
+ thread_db_find_new_threads ();
+ thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread);
+
+ gdb_assert (thread_info != NULL);
+
+ return (thread_info->ptid);
+}
+
static void
init_thread_db_ops (void)
{
@@ -1163,6 +1190,7 @@ init_thread_db_ops (void)
thread_db_ops.to_is_async_p = thread_db_is_async_p;
thread_db_ops.to_async = thread_db_async;
thread_db_ops.to_async_mask = thread_db_async_mask;
+ thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid;
thread_db_ops.to_magic = OPS_MAGIC;
}

diff -r b2b21339d264 gdb/testsuite/gdb.base/completion.exp
--- a/gdb/testsuite/gdb.base/completion.exp Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/testsuite/gdb.base/completion.exp Mon Sep 22 15:50:06 2008 -0700
@@ -223,7 +223,7 @@ gdb_expect {
-re "^info t foo\\\x07$"\
{ send_gdb "\n"
gdb_expect {
- -re "Ambiguous info command \"t foo\": target, terminal, threads, tp, tracepoints, types\\..*$gdb_prompt $"\
+ -re "Ambiguous info command \"t foo\": target, tasks, terminal, threads, tp, tracepoints, types\\..*$gdb_prompt $"\
{ pass "complete 'info t foo'"}
-re ".*$gdb_prompt $" { fail "complete 'info t foo'"}
timeout {fail "(timeout) complete 'info t foo'"}
@@ -239,7 +239,7 @@ gdb_expect {
-re "^info t\\\x07$"\
{ send_gdb "\n"
gdb_expect {
- -re "Ambiguous info command \"t\": target, terminal, threads, tp, tracepoints, types\\..
+ -re "Ambiguous info command \"t\": target, tasks, terminal, threads, tp, tracepoints, types\\..
*$gdb_prompt $"\
{ pass "complete 'info t'"}
-re ".*$gdb_prompt $" { fail "complete 'info t'"}
@@ -257,7 +257,7 @@ gdb_expect {
-re "^info t \\\x07$"\
{ send_gdb "\n"
gdb_expect {
- -re "Ambiguous info command \"t \": target, terminal, threads, tp, tracepoints, types\\..
+ -re "Ambiguous info command \"t \": target, tasks, terminal, threads, tp, tracepoints, types\\..
*$gdb_prompt $"\
{ pass "complete 'info t '"}
-re ".*$gdb_prompt $" { fail "complete 'info t '"}

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diff -r b2b21339d264 gdb/doc/gdb.texinfo
--- a/gdb/doc/gdb.texinfo Sun Sep 21 14:50:58 2008 -0700
+++ b/gdb/doc/gdb.texinfo Mon Sep 22 15:50:17 2008 -0700
@@ -11042,6 +11042,8 @@ to be difficult.
* Omissions from Ada:: Restrictions on the Ada expression syntax.
* Additions to Ada:: Extensions of the Ada expression syntax.
* Stopping Before Main Program:: Debugging the program during elaboration.
+* Ada Tasks:: Listing and setting breakpoints in tasks.
+* Ada Tasks and Core Files:: Tasking Support when Debugging Core Files
* Ada Glitches:: Known peculiarities of Ada mode.
@end menu

@@ -11361,6 +11363,194 @@ Manual, the elaboration code is invoked
@code{adainit}. To run your program up to the beginning of
elaboration, simply use the following two commands:
@code{tbreak adainit} and @code{run}.
+
+@node Ada Tasks
+@subsubsection Extensions for Ada Tasks
+@cindex Ada, tasking
+
+Support for Ada tasks is analogous to that for threads (@pxref{Threads}).
+When in Ada mode (that is, when the ``current language'' is Ada), @value{GDBN}
+allows the following task-related commands:
+
+@table @code
+@kindex info tasks
+@item info tasks
+This command shows a list of current Ada tasks, as in the following example:
+
+
+@smallexample
+@iftex
+@leftskip=0.5cm
+@end iftex
+(@value{GDBP}) info tasks
+ ID TID P-ID Pri State Name
+ 1 8088000 0 15 Child Activation Wait main_task
+ 2 80a4000 1 15 Accept Statement b
+ 3 809a800 1 15 Child Activation Wait a
+* 4 80ae800 3 15 Running c
+
+@end smallexample
+
+@noindent
+In this listing, the asterisk before the last task indicates it to be the
+task currently being inspected.
+
+@table @asis
+@item ID
+Represents gdb's internal task number.
+
+@item TID
+The Ada task ID.
+
+@item P-ID
+The parent's task ID (@value{GDBN}'s internal task number).
+
+@item Pri
+The base priority of the task.
+
+@item State
+Current state of the task.
+
+@itemize @bullet
+@item
+Unactivated: the task has been created but has not been activated.
+It cannot be executing.
+
+@item
+Running: the task currently running.
+
+@item
+Runnable: the task is not blocked for any reason known to Ada.
+(It may be waiting for a mutex, though.)
+It is conceptually "executing" in normal mode.
+
+@item
+Terminated: the task is terminated, in the sense of ARM 9.3 (5).
+Any dependents that were waiting on terminate
+alternatives have been awakened and have terminated themselves.
+
+@item
+Child Activation Wait: the task is waiting for created tasks to complete
+activation.
+
+@item
+Accept Statement: the task is waiting on an accept or selective wait statement.
+
+@item
+Waiting on entry call: the task is waiting on an entry call.
+
+@item
+Async Select Wait: the task is waiting to start the abortable part of an
+asynchronous select statement.
+
+@item
+Delay Sleep: the task is waiting on a select statement with only a delay
+alternative open.
+
+@item
+Child Termination Wait: the task is sleeping
+having completed a master within itself,
+and is waiting for the tasks dependent on that master to become
+terminated or waiting on a terminate Phase.
+
+@item
+Wait Child in Term Alt: the task is sleeping
+waiting for tasks on terminate alternatives to finish terminating.
+
+@item
+Accepting RV with @var{taskno}: the task is accepting a rendez-vous with the
+task @var{taskno}
+@end itemize
+
+@item Name
+Name of the task in the program.
+
+@end table
+
+@kindex info task @var{taskno}
+@item info task @var{taskno}
+This command shows detailled informations on the specified task, as in
+the following example:
+@smallexample
+@iftex
+@leftskip=0.5cm
+@end iftex
+(@value{GDBP}) info tasks
+ ID TID P-ID Pri State Name
+ 1 8077880 0 15 Child Activation Wait main_task
+* 2 807c468 1 15 Running task_1
+(@value{GDBP}) info task 2
+Ada Task: 0x807c468
+Name: task_1
+Thread: 0x807f378
+Parent: 1 (main_task)
+Base Priority: 15
+State: Runnable
+@end smallexample
+
+@item task
+@kindex task
+@cindex current task ID
+This command prints the ID of the current task.
+
+@smallexample
+@iftex
+@leftskip=0.5cm
+@end iftex
+(@value{GDBP}) info tasks
+ ID TID P-ID Pri State Name
+ 1 8077870 0 15 Child Activation Wait main_task
+* 2 807c458 1 15 Running t
+(@value{GDBP}) task
+[Current task is 2]
+@end smallexample
+
+@item task @var{taskno}
+@kindex task @var{taskno}
+@cindex task switching
+This command is like the @code{thread @var{threadno}}
+command (@pxref{Threads}). It switches the context of debugging
+from the current task to the given task.
+
+@smallexample
+@iftex
+@leftskip=0.5cm
+@end iftex
+(@value{GDBP}) info tasks
+ ID TID P-ID Pri State Name
+ 1 8077870 0 15 Child Activation Wait main_task
+* 2 807c458 1 15 Running t
+(@value{GDBP}) task 1
+[Switching to task 1]
+#0 0x8067726 in pthread_cond_wait ()
+(@value{GDBP}) bt
+#0 0x8067726 in pthread_cond_wait ()
+#1 0x8056714 in system.os_interface.pthread_cond_wait ()
+#2 0x805cb63 in system.task_primitives.operations.sleep ()
+#3 0x806153e in system.tasking.stages.activate_tasks ()
+#4 0x804aacc in un () at un.adb:5
+@end smallexample
+
+@end table
+
+@node Ada Tasks and Core Files
+@subsubsection Tasking Support when Debugging Core Files
+@cindex Ada tasking and core file debugging
+
+When inspecting a core file, as opposed to debugging a live program,
+tasking support may be limited or even unavailable, depending on
+the platform being used.
+For instance, on x86-linux, the list of tasks is available, but task
+switching is not supported. On Tru64, however, task switching will work
+as usual.
+
+On certain platforms, including Tru64, the debugger needs to perform some
+memory writes in order to provide Ada tasking support. When inspecting
+a core file, this means that the core file must be opened with
+read-write privileges, using the command @samp{"set write on"}.
+Under these
+circumstances, you should make a backup copy of the core file
+before inspecting it with @value{GDBN}.

@node Ada Glitches
@subsubsection Known Peculiarities of Ada Mode