[commit] Don't allow more than one LWP to have `do_step' flag set at a time

[commit] Don't allow more than one LWP to have `do_step' flag set at a time

[Kevin Buettner]

I've just committed the patch below.  As indicated by the comment, the
software singlestep code internal to RDA does not expect to step more
than one thread at a time.  (It's rather naive about how it saves the
singlestep breakpoints.)  I considered making it more robust, it seems
to me that GDB only expects one thread to be singlestepped at a time.
At the present time, I don't think there's any functionality to be gained
by allowing more than one thread to singlestep simultaneously.

	* lwp-pool.c (clear_all_do_step_flags): New function.
	(lwp_pool_singlestep_lwp): Use it.

Index: lwp-pool.c
===================================================================
RCS file: /cvs/src/src/rda/unix/lwp-pool.c,v
retrieving revision 1.5
diff -u -p -r1.5 lwp-pool.c
--- lwp-pool.c	10 Nov 2005 21:32:15 -0000	1.5
+++ lwp-pool.c	11 Nov 2005 20:26:23 -0000
@@ -1395,6 +1395,23 @@ lwp_pool_continue_lwp (struct gdbserv *s
 }
 
 
+/* Clear the `do_step' flags for all LWPs in the hash table.  */
+
+static void
+clear_all_do_step_flags (void)
+{
+  int i;
+
+  for (i = 0; i < hash_size; i++)
+    {
+      struct lwp *l = hash[i];
+
+      if (l)
+	l->do_step = 0;
+    }
+}
+
+
 int
 lwp_pool_singlestep_lwp (struct gdbserv *serv, pid_t lwp, int signal)
 {
@@ -1406,6 +1423,12 @@ lwp_pool_singlestep_lwp (struct gdbserv 
     fprintf (stderr, "lwp_pool_singlestep_lwp (%p, %d, %d)\n",
 	     serv, (int) lwp, signal);
 
+  /* Neither GDB nor the software singlestep code contained in RDA
+     expect more than one LWP to be stepped simultaneously.  Clear the
+     `do_step' flag in all LWPs.  The flag for the LWP that we're about
+     to step will be set later on.  */
+  clear_all_do_step_flags ();
+
   switch (l->state)
     {
     case lwp_state_uninitialized: