[commit] Implement task switching on solaris targets.

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

I just noticed that task switching isn't working on Solaris. For instance,
on sparc-solaris, we get:

    (gdb) task 1
    [new-thread notifications]
    Unable to compute thread ID for task 1.
    Cannot switch to this task.

But the first clue that things aren't working is the lack of '*' marking
the current task in the "info tasks" output:

    (gdb) info tasks
      ID       TID P-ID Pri State                  Name
       1     79c10    0  15 Runnable               main_task
       2     7a878    1  15 Accept or Select Term  my_callee
       3     7df00    1  15 Runnable               my_caller

This is because the default task-info-to-ptid conversion routine does
not work for Solaris.  Fixed with the attached patch.

Now, we get:

    (gdb) info tasks
      ID       TID P-ID Pri State                  Name
       1     79c10    0  15 Runnable               main_task
       2     7a878    1  15 Accept or Select Term  my_callee
    *  3     7df00    1  15 Runnable               my_caller
    (gdb) task 2
    [Switching to task 2]
    #5  0x0002beb0 in task_switch.callee (<_task>=0x7a4b8) at task_switch.adb:29
    29            accept Finito do
    (gdb) task 1
    [Switching to task 1]
    #1  0x0002ba98 in task_switch () at task_switch.adb:55
    55      end Task_Switch;


gdb/ChangeLog:

        * sol-thread.c (thread_db_find_thread_from_tid)
        (sol_get_ada_task_ptid): New functions.
        (init_sol_thread_ops): Set sol_thread_ops.to_get_ada_task_ptid.

Tested manually, but it can only affect Ada tasking. We've also had
this patch in our tree for a loooong time, now...

---
 gdb/ChangeLog    |    7 +++++++
 gdb/sol-thread.c |   35 +++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 582cc15..216d137 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2010-05-07  Joel Brobecker  <brobecker@adacore.com>
+
+	Implement task switching on solaris targets.
+	* sol-thread.c (thread_db_find_thread_from_tid)
+	(sol_get_ada_task_ptid): New functions.
+	(init_sol_thread_ops): Set sol_thread_ops.to_get_ada_task_ptid.
+
 2010-05-07  Pedro Alves  <pedro@codesourcery.com>
 
 	* remote.c (remote_query_supported_append): Use reconcat.
diff --git a/gdb/sol-thread.c b/gdb/sol-thread.c
index 3e7183f..d18ae44 100644
--- a/gdb/sol-thread.c
+++ b/gdb/sol-thread.c
@@ -1288,6 +1288,40 @@ info_solthreads (char *args, int from_tty)
 		    TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
 }
 
+/* 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 (ptid_get_tid (thread->ptid) == *tid)
+    return 1;
+
+  return 0;
+}
+
+static ptid_t
+sol_get_ada_task_ptid (long lwp, long thread)
+{
+  struct thread_info *thread_info =
+    iterate_over_threads (thread_db_find_thread_from_tid, &thread);
+
+  if (thread_info == NULL)
+    {
+      /* The list of threads is probably not up to date.  Find any
+         thread that is missing from the list, and try again.  */
+      sol_find_new_threads (&current_target);
+      thread_info = iterate_over_threads (thread_db_find_thread_from_tid,
+                                          &thread);
+    }
+
+  gdb_assert (thread_info != NULL);
+
+  return (thread_info->ptid);
+}
+
 static void
 init_sol_thread_ops (void)
 {
@@ -1305,6 +1339,7 @@ init_sol_thread_ops (void)
   sol_thread_ops.to_pid_to_str = solaris_pid_to_str;
   sol_thread_ops.to_find_new_threads = sol_find_new_threads;
   sol_thread_ops.to_stratum = thread_stratum;
+  sol_thread_ops.to_get_ada_task_ptid = sol_get_ada_task_ptid;
   sol_thread_ops.to_magic = OPS_MAGIC;
 }
 
-- 
1.6.3.3