[PATCH] Minor Ada task cleanups

Tom Tromey
2019-02-15T21:23:13Z

While working on the Ada task code, I noticed a few things that could
be cleaned up:

* task_list_valid_p was not set in all cases in ada_build_task_list.
This causes many needless re-fetches of the task list.

* task_list_valid_p can be bool, and various functions can also return
bool.

* Nothing checks the return value of read_known_tasks, so it can be
changed to return void.

* The call to ada_build_task_list in
ravenscar_thread_target::update_thread_list is redundant, because
this is the first thing done by iterate_over_live_ada_tasks.

Tested using the internal AdaCore test suite against a ravenscar
target.

gdb/ChangeLog
2019-02-15 Tom Tromey <tromey@adacore.com>

* ravenscar-thread.c
(ravenscar_thread_target::update_thread_list): Don't call
ada_build_task_list.
* ada-lang.h (ada_build_task_list): Don't declare.
* ada-tasks.c (struct ada_tasks_inferior_data)
<task_list_valid_p>: Now bool.
(read_known_tasks, ada_task_list_changed)
(ada_tasks_invalidate_inferior_data): Update.
(read_known_tasks_array): Return bool.
(read_known_tasks_list): Likewise.
(read_known_tasks): Return void.
(ada_build_task_list): Now static.
---
gdb/ChangeLog | 15 +++++++++++
gdb/ada-lang.h | 2 --
gdb/ada-tasks.c | 58 ++++++++++++++++++++++--------------------
gdb/ravenscar-thread.c | 2 --
4 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3ef09fd733b..b1f69402a26 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,18 @@
+2019-02-15 Tom Tromey <tromey@adacore.com>
+
+ * ravenscar-thread.c
+ (ravenscar_thread_target::update_thread_list): Don't call
+ ada_build_task_list.
+ * ada-lang.h (ada_build_task_list): Don't declare.
+ * ada-tasks.c (struct ada_tasks_inferior_data)
+ <task_list_valid_p>: Now bool.
+ (read_known_tasks, ada_task_list_changed)
+ (ada_tasks_invalidate_inferior_data): Update.
+ (read_known_tasks_array): Return bool.
+ (read_known_tasks_list): Likewise.
+ (read_known_tasks): Return void.
+ (ada_build_task_list): Now static.
+
2019-02-15 Tom Tromey <tromey@adacore.com>

* ravenscar-thread.c (ravenscar_thread_target::resume)
diff --git a/gdb/ada-lang.h b/gdb/ada-lang.h
index 14470d5d434..ee03dbd2aad 100644
--- a/gdb/ada-lang.h
+++ b/gdb/ada-lang.h
@@ -411,8 +411,6 @@ extern void iterate_over_live_ada_tasks

extern const char *ada_get_tcb_types_info (void);

-extern int ada_build_task_list (void);
-
extern void print_ada_task_info (struct ui_out *uiout,
char *taskno_str,
struct inferior *inf);
diff --git a/gdb/ada-tasks.c b/gdb/ada-tasks.c
index e994147a669..beef575c669 100644
--- a/gdb/ada-tasks.c
+++ b/gdb/ada-tasks.c
@@ -26,6 +26,8 @@
#include "progspace.h"
#include "objfiles.h"

+static int ada_build_task_list ();
+
/* 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"
@@ -221,7 +223,7 @@ struct ada_tasks_inferior_data
/* When nonzero, this flag indicates that the task_list field
below is up to date. When set to zero, the list has either
not been initialized, or has potentially become stale. */
- int task_list_valid_p = 0;
+ bool task_list_valid_p = false;

/* The list of Ada tasks.

@@ -785,9 +787,9 @@ add_ada_task (CORE_ADDR task_id, struct inferior *inf)
}

/* Read the Known_Tasks array from the inferior memory, and store
- it in the current inferior's TASK_LIST. Return non-zero upon success. */
+ it in the current inferior's TASK_LIST. Return true upon success. */

-static int
+static bool
read_known_tasks_array (struct ada_tasks_inferior_data *data)
{
const int target_ptr_byte = TYPE_LENGTH (data->known_tasks_element);
@@ -808,13 +810,13 @@ read_known_tasks_array (struct ada_tasks_inferior_data *data)
add_ada_task (task_id, current_inferior ());
}

- return 1;
+ return true;
}

/* Read the known tasks from the inferior memory, and store it in
- the current inferior's TASK_LIST. Return non-zero upon success. */
+ the current inferior's TASK_LIST. Return true upon success. */

-static int
+static bool
read_known_tasks_list (struct ada_tasks_inferior_data *data)
{
const int target_ptr_byte = TYPE_LENGTH (data->known_tasks_element);
@@ -825,7 +827,7 @@ read_known_tasks_list (struct ada_tasks_inferior_data *data)

/* Sanity check. */
if (pspace_data->atcb_fieldno.activation_link < 0)
- return 0;
+ return false;

/* Build a new list by reading the ATCBs. Read head of the list. */
read_memory (data->known_tasks_addr, known_tasks, target_ptr_byte);
@@ -846,7 +848,7 @@ read_known_tasks_list (struct ada_tasks_inferior_data *data)
pspace_data->atcb_fieldno.activation_link));
}

- return 1;
+ return true;
}

/* Set all fields of the current inferior ada-tasks data pointed by DATA.
@@ -944,11 +946,10 @@ ada_tasks_inferior_data_sniffer (struct ada_tasks_inferior_data *data)
}

/* Read the known tasks from the current inferior's memory, and store it
- in the current inferior's data TASK_LIST.
- Return non-zero upon success. */
+ in the current inferior's data TASK_LIST. */

-static int
-read_known_tasks (void)
+static void
+read_known_tasks ()
{
struct ada_tasks_inferior_data *data =
get_ada_tasks_inferior_data (current_inferior ());
@@ -965,29 +966,30 @@ read_known_tasks (void)
ada_tasks_inferior_data_sniffer (data);
gdb_assert (data->known_tasks_kind != ADA_TASKS_UNKNOWN);

+ /* Step 3: Set task_list_valid_p, to avoid re-reading the Known_Tasks
+ array unless needed. */
switch (data->known_tasks_kind)
{
- case ADA_TASKS_NOT_FOUND: /* Tasking not in use in inferior. */
- return 0;
- case ADA_TASKS_ARRAY:
- return read_known_tasks_array (data);
- case ADA_TASKS_LIST:
- return read_known_tasks_list (data);
+ case ADA_TASKS_NOT_FOUND: /* Tasking not in use in inferior. */
+ break;
+ case ADA_TASKS_ARRAY:
+ data->task_list_valid_p = read_known_tasks_array (data);
+ break;
+ case ADA_TASKS_LIST:
+ data->task_list_valid_p = read_known_tasks_list (data);
+ break;
+ case ADA_TASKS_UNKNOWN:
+ data->task_list_valid_p = true;
+ break;
}
-
- /* Step 3: Set task_list_valid_p, to avoid re-reading the Known_Tasks
- array unless needed. Then report a success. */
- data->task_list_valid_p = 1;
-
- return 1;
}

/* Build the task_list by reading the Known_Tasks array from
the inferior, and return the number of tasks in that list
(zero means that the program is not using tasking at all). */

-int
-ada_build_task_list (void)
+static int
+ada_build_task_list ()
{
struct ada_tasks_inferior_data *data;

@@ -1343,7 +1345,7 @@ ada_task_list_changed (struct inferior *inf)
{
struct ada_tasks_inferior_data *data = get_ada_tasks_inferior_data (inf);

- data->task_list_valid_p = 0;
+ data->task_list_valid_p = false;
}

/* Invalidate the per-program-space data. */
@@ -1362,7 +1364,7 @@ ada_tasks_invalidate_inferior_data (struct inferior *inf)
struct ada_tasks_inferior_data *data = get_ada_tasks_inferior_data (inf);

data->known_tasks_kind = ADA_TASKS_UNKNOWN;
- data->task_list_valid_p = 0;
+ data->task_list_valid_p = false;
}

/* The 'normal_stop' observer notification callback. */
diff --git a/gdb/ravenscar-thread.c b/gdb/ravenscar-thread.c
index 05a83200a1e..cb4f26a3472 100644
--- a/gdb/ravenscar-thread.c
+++ b/gdb/ravenscar-thread.c
@@ -374,8 +374,6 @@ ravenscar_add_thread (struct ada_task_info *task)
void
ravenscar_thread_target::update_thread_list ()
{
- ada_build_task_list ();
-
/* Do not clear the thread list before adding the Ada task, to keep
the thread that the process stratum has included into it
(m_base_ptid) and the running thread, that may not have been included
--
2.20.1