Re: Unwinding dummy frames on the i386

[Mark Kettenis <kettenis at chello dot nl>]

   Date: Fri, 07 Mar 2003 17:13:24 -0500
   From: Andrew Cagney <ac131313 at redhat dot com>

   > For now I've worked around this by having my own do-nothing
   > i386_save_dummy_frame_tos(), and having i386_unwind_dummy_id() return
   > contents of the (saved) frame pointer register for the frame's base.
   > Is there a better way to solve this?

   Can i386_save_dummy_frame_tos() save the `frame pointer register' that 
   the unwind_dummy_id() method later returns?

If reading the current value of FP_REGNUM from current_regcache is OK
the answer is yes.  Hmm, in that case it's probably an even better
idea to actually set the frame pointer register to the top-of-stack in
i386_save_dummy_frame_tos().  That way, we won't have a problem when
there are several frameless function calls in a row.  Is writing into
current_regcache acceptable?

   While the TOS in save_dummy_frame_tos() might have once stood for 
   top-of-stack, there isn't anything saying that it has to be the stack 
   top.  A better name for tha functioin's successor would be 
   save_dummy_frame_id()

Agreed.

Mark