Re: [PATCH, RFC] Enable libsanitizer on powerpc{,64}

[Jakub Jelinek <jakub at redhat dot com>]

On Mon, Nov 19, 2012 at 08:49:30AM -0600, Peter Bergner wrote:
> On Mon, 2012-11-19 at 15:29 +0100, Jakub Jelinek wrote:
> > On Fri, Nov 16, 2012 at 05:08:06PM -0600, Peter Bergner wrote:
> > > One question that I have is that the toplev.c test for port support
> > > tests for !FRAME_GROWS_DOWNWARD.  The rs6000 port has FRAME_GROWS_DOWNWARD
> > > defined as (flag_stack_protect != 0), so ASAN only works when we use
> > > -fstack-protector.  Is there a technical reason why FRAME_GROWS_DOWNWARD
> > > must be false?
> > 
> > It would be way too much work to support FRAME_GROWS_DOWNWARD.
> 
> Do you you have a pointer or a reference that describes why ASAN
> relies on that?  I don't doubt you are correct, but for my own
> education, I'd like to know the reason.

Look at cfgexpand.c changes done for asan, it is modelled there after
the stack protector layout code, would need to take into account the other
direction.

	Jakub