[PATCH 2/4] gdb: used scoped_restore_frame in update_watchpoint

[Andrew Burgess <aburgess@redhat.com>]

I was doing some int to bool cleanup in update_watchpoint, and I
noticed a manual version of scoped_restore_selected_frame.  As always
when these things are done manually, there is the chance that, in an
error case, we might leave the wrong frame selected.

This commit updates things to use scoped_restore_selected_frame, and
also converts a local variable from int to bool.

The only user visible change after this commit is in the case where
update_watchpoint throws an error - we should now correctly restore
the previously selected frame.  Otherwise, this commit should be
invisible to the user.
---
 gdb/breakpoint.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 6e1a15e4f1b..57281a199b0 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -1926,9 +1926,7 @@ add_dummy_location (struct breakpoint *b,
 static void
 update_watchpoint (struct watchpoint *b, int reparse)
 {
-  int within_current_scope;
-  struct frame_id saved_frame_id;
-  int frame_saved;
+  bool within_current_scope;
 
   /* If this is a local watchpoint, we only want to check if the
      watchpoint frame is in scope if the current thread is the thread
@@ -1938,12 +1936,12 @@ update_watchpoint (struct watchpoint *b, int reparse)
 
   if (b->disposition == disp_del_at_next_stop)
     return;
- 
-  frame_saved = 0;
+
+  gdb::optional<scoped_restore_selected_frame> restore_frame;
 
   /* Determine if the watchpoint is within scope.  */
   if (b->exp_valid_block == NULL)
-    within_current_scope = 1;
+    within_current_scope = true;
   else
     {
       struct frame_info *fi = get_current_frame ();
@@ -1962,8 +1960,7 @@ update_watchpoint (struct watchpoint *b, int reparse)
       /* FIXME drow/2003-09-09: It would be nice if evaluate_expression
 	 took a frame parameter, so that we didn't have to change the
 	 selected frame.  */
-      frame_saved = 1;
-      saved_frame_id = get_frame_id (get_selected_frame (NULL));
+      restore_frame.emplace ();
 
       fi = frame_find_by_id (b->watchpoint_frame);
       within_current_scope = (fi != NULL);
@@ -2229,10 +2226,6 @@ in which its expression is valid.\n"),
 		  b->number);
       watchpoint_del_at_next_stop (b);
     }
-
-  /* Restore the selected frame.  */
-  if (frame_saved)
-    select_frame (frame_find_by_id (saved_frame_id));
 }
 
 
-- 
2.25.4