enum unwind_stop_reason stop_reason;
};
+/* A frame stash used to speed up frame lookups. */
+
+/* We currently only stash one frame at a time, as this seems to be
+ sufficient for now. */
+static struct frame_info *frame_stash = NULL;
+
+/* Add the following FRAME to the frame stash. */
+
+static void
+frame_stash_add (struct frame_info *frame)
+{
+ frame_stash = frame;
+}
+
+/* Search the frame stash for an entry with the given frame ID.
+ If found, return that frame. Otherwise return NULL. */
+
+static struct frame_info *
+frame_stash_find (struct frame_id id)
+{
+ if (frame_stash && frame_id_eq (frame_stash->this_id.value, id))
+ return frame_stash;
+
+ return NULL;
+}
+
+/* Invalidate the frame stash by removing all entries in it. */
+
+static void
+frame_stash_invalidate (void)
+{
+ frame_stash = NULL;
+}
+
/* Flag to control debugging. */
int frame_debug;
get_frame_id (struct frame_info *fi)
{
if (fi == NULL)
- {
- return null_frame_id;
- }
+ return null_frame_id;
+
if (!fi->this_id.p)
{
if (frame_debug)
fprintf_unfiltered (gdb_stdlog, " }\n");
}
}
+
+ frame_stash_add (fi);
+
return fi->this_id.value;
}
if (!frame_id_p (id))
return NULL;
+ /* Try using the frame stash first. Finding it there removes the need
+ to perform the search by looping over all frames, which can be very
+ CPU-intensive if the number of frames is very high (the loop is O(n)
+ and get_prev_frame performs a series of checks that are relatively
+ expensive). This optimization is particularly useful when this function
+ is called from another function (such as value_fetch_lazy, case
+ VALUE_LVAL (val) == lval_register) which already loops over all frames,
+ making the overall behavior O(n^2). */
+ frame = frame_stash_find (id);
+ if (frame)
+ return frame;
+
for (frame = get_current_frame (); ; frame = prev_frame)
{
struct frame_id this = get_frame_id (frame);
current_frame = NULL; /* Invalidate cache */
select_frame (NULL);
+ frame_stash_invalidate ();
if (frame_debug)
fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
}