[PATCH 4/4] DEC threads: Simplify updating the thread list

Pedro Alves
2014-10-02T16:21:46Z

Seems to me that we can simplify DEC thread's
target_update_thread_list implementation, avoiding the need to build
the array of GDB threads.

I have no way to test this.

gdb/
2014-10-02 Pedro Alves <palves@redhat.com>

* dec-thread.c (dec_thread_count_gdb_threads)
(dec_thread_add_gdb_thread): Delete.
(dec_thread_update_thread_list): Delete.
(dec_thread_find_new_threads): Rename to ...
(dec_thread_update_thread_list): ... this. Delete GDB-size
threads that are no longer found in dec_thread_list.
(resync_thread_list): Delete.
(dec_thread_wait): Call dec_thread_update_thread_list instead of
resync_thread_list.
---
gdb/dec-thread.c | 93 +++++++++++++-------------------------------------------
1 file changed, 21 insertions(+), 72 deletions(-)

diff --git a/gdb/dec-thread.c b/gdb/dec-thread.c
index fc43153..d5cfad2 100644
--- a/gdb/dec-thread.c
+++ b/gdb/dec-thread.c
@@ -369,40 +369,33 @@ update_dec_thread_list (void)
pthreadDebugThdSeqDestroy (debug_context);
}

-/* A callback to count the number of threads known to GDB. */
-
-static int
-dec_thread_count_gdb_threads (struct thread_info *ignored, void *context)
-{
- int *count = (int *) context;
-
- *count = *count + 1;
- return 0;
-}
-
-/* A callback that saves the given thread INFO at the end of an
- array. The end of the array is given in the CONTEXT and is
- incremented once the info has been added. */
-
-static int
-dec_thread_add_gdb_thread (struct thread_info *info, void *context)
-{
- struct thread_info ***listp = (struct thread_info ***) context;
-
- **listp = info;
- *listp = *listp + 1;
- return 0;
-}
-
-/* Find new threads. */
+/* Implement the update_thread_list target_ops method. */

static void
-dec_thread_find_new_threads (struct target_ops *ops)
+dec_thread_update_thread_list (struct target_ops *ops)
{
int i;
struct dec_thread_info *info;
+ struct thread_info *tp, *tmp;

update_dec_thread_list ();
+
+ /* Delete GDB-side threads no longer found in dec_thread_list. */
+ ALL_NON_EXITED_THREADS_SAFE (tp, tmp)
+ {
+ for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info); i++)
+ {
+ if (ptid_equal (info->ptid, tp->ptid))
+ break;
+ }
+ if (i == VEC_length (dec_thread_info_s, dec_thread_list))
+ {
+ /* Not found. */
+ delete_thread (tp->ptid);
+ }
+ }
+
+ /* And now add new threads. */
for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info); i++)
{
ptid_t ptid = ptid_build_from_info (*info);
@@ -412,50 +405,6 @@ dec_thread_find_new_threads (struct target_ops *ops)
}
}

-/* Implement the update_thread_list target_ops method. */
-
-static void
-dec_thread_update_thread_list (struct target_ops *ops)
-{
- int i;
- struct dec_thread_info *info;
-
- /* Delete dead threads. */
- prune_threads ();
-
- /* Now find new threads. */
- dec_thread_find_new_threads (ops);
-}
-
-/* Resynchronize the list of threads known by GDB with the actual
- list of threads reported by libpthread_debug. */
-
-static void
-resync_thread_list (struct target_ops *ops)
-{
- int i;
- int num_gdb_threads = 0;
- struct thread_info **gdb_thread_list;
- struct thread_info **next_thread_info;
-
- /* Add new threads. */
- dec_thread_find_new_threads (ops);
-
- /* Remove threads that no longer exist. To help with the search,
- we build an array of GDB threads, and then iterate over this
- array. */
-
- iterate_over_threads (dec_thread_count_gdb_threads,
- (void *) &num_gdb_threads);
- gdb_thread_list = alloca (num_gdb_threads * sizeof (struct thread_info *));
- next_thread_info = gdb_thread_list;
- iterate_over_threads (dec_thread_add_gdb_thread, (void *) &next_thread_info);
-
- for (i = 0; i < num_gdb_threads; i++)
- if (!dec_thread_ptid_is_alive (gdb_thread_list[i]->ptid))
- delete_thread (gdb_thread_list[i]->ptid);
-}
-
/* The "to_detach" method of the dec_thread_ops. */

static void
@@ -502,7 +451,7 @@ dec_thread_wait (struct target_ops *ops,

/* The ptid returned by the target beneath us is the ptid of the process.
We need to find which thread is currently active and return its ptid. */
- resync_thread_list (ops);
+ dec_thread_update_thread_list (ops);
active_ptid = get_active_ptid ();
if (ptid_equal (active_ptid, null_ptid))
return ptid;
--
1.9.3