* frame.c (get_prev_frame_1): Work around GCC bug.

* frame.h: Add comment about GCC bug.

1 files changed, 16 insertions, 1 deletions

diff --git a/gdb/frame.h b/gdb/frame.h
index 2ab8b8e..55d357c 100644
--- a/gdb/frame.h
+++ b/gdb/frame.h
@@ -310,7 +310,22 @@ extern CORE_ADDR get_frame_base (struct frame_info *);
 
 /* Return the per-frame unique identifer.  Can be used to relocate a
    frame after a frame cache flush (and other similar operations).  If
-   FI is NULL, return the null_frame_id.  */
+   FI is NULL, return the null_frame_id.
+
+   NOTE: kettenis/20040508: These functions return a structure.  On
+   platforms where structures are returned in static storage (vax,
+   m68k), this may trigger compiler bugs in code like:
+
+   if (frame_id_eq (get_frame_id (l), get_frame_id (r)))
+
+   where the return value from the first get_frame_id (l) gets
+   overwritten by the second get_frame_id (r).  Please avoid writing
+   code like this.  Use code like:
+
+   struct frame_id id = get_frame_id (l);
+   if (frame_id_eq (id, get_frame_id (r)))
+
+   instead, since that avoids the bug.  */
 extern struct frame_id get_frame_id (struct frame_info *fi);
 extern struct frame_id frame_unwind_id (struct frame_info *next_frame);