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Re: [PATCH] Add soft frame pointer pseudo on ppc{32,64} and prepare for (optional) FRAME_GROWS_DOWNWARD
- From: Richard Henderson <rth at redhat dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org, etoh at jp dot ibm dot com, arjanv at redhat dot com, drepper at redhat dot com
- Date: Sun, 26 Jun 2005 16:23:37 -0700
- Subject: Re: [PATCH] Add soft frame pointer pseudo on ppc{32,64} and prepare for (optional) FRAME_GROWS_DOWNWARD
- References: <20050624224155.GN22349@devserv.devel.redhat.com>
On Fri, Jun 24, 2005 at 06:41:56PM -0400, Jakub Jelinek wrote:
> ... the ABI mandated
> stack layout is kept, all that FRAME_GROWS_DOWNWARD changes
> is the order of local variables on the stack (and in some
> cases FRAME_GROWS_DOWNWARD can result in additional 8 bytes
> of padding, as the variable layout code needs to know
> alignment before whole size of the frame is known).
So the ABI mandates that the saved registers are above the local
stack frame area? Otherwise I can't think of any reason why you
couldn't move them lower, which would preclude STARTING_FRAME_OFFSET
from being a constant.
I'll have to let an rs6000 maintainer review this patch.
r~