* stack.c (select_frame): Check that selected_frame and the

specified level are as expected.
* blockframe.c (get_prev_frame): Set the `level' from next_frame.
Update copyright.
* frame.h (struct frame_info): Add field `level'.  Update
copyright.
Work-in-progress PR gdb/464.

1 files changed, 32 insertions, 0 deletions

diff --git a/gdb/stack.c b/gdb/stack.c
index bedb6ee..a348934 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1458,6 +1458,38 @@ select_frame (struct frame_info *fi, int level)
 
   selected_frame = fi;
   selected_frame_level = level;
+  /* FIXME: cagney/2002-04-05: It can't be this easy (and looking at
+     the increasingly complex list of checkes, it wasn't)!  GDB is
+     dragging around, and constantly updating, the global variable
+     selected_frame_level.  Surely all that was needed was for the
+     level to be computed direct from the frame (by counting back to
+     the inner-most frame) or, as has been done here using a cached
+     value.  For moment, check that the expected and the actual level
+     are consistent.  If, after a few weeks, no one reports that this
+     assertion has failed, the global selected_frame_level and many
+     many parameters can all be deleted.  */
+  if (fi == NULL && level == -1)
+    /* Ok.  The target is clearing the selected frame as part of a
+       cache flush.  */
+    ;
+  else if (fi != NULL && fi->level == level)
+    /* Ok.  What you would expect.  Level is redundant.  */
+    ;
+  else if (fi != NULL && level == -1)
+    /* Ok.  See breakpoint.c.  The watchpoint code changes the
+       selected frame to the frame that contains the watchpoint and
+       then, later changes it back to the old value.  The -1 is used
+       as a marker so that the watchpoint code can easily detect that
+       things are not what they should be.  Why the watchpoint code
+       can't mindlessly save/restore the selected frame I don't know,
+       hopefully it can be simplified that way.  Hopefully the global
+       selected_frame can be replaced by a frame parameter, making
+       still more simplification possible.  */
+    ;
+  else
+    internal_error (__FILE__, __LINE__,
+		    "oops! fi=0x%p, fi->level=%d, level=%d",
+		    fi, fi ? fi->level : -1, level);
   if (selected_frame_level_changed_hook)
     selected_frame_level_changed_hook (level);