Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Thu, 28 Jun 2018 16:21:28 -0400
From: Rich Felker <dalias@...c.org>
To: musl@...ts.openwall.com
Subject: Re: [PATCH] optimize explicit_bzero for size

On Thu, Jun 28, 2018 at 08:42:13PM +0100, David CARLIER wrote:
> On Thu, 28 Jun 2018 at 20:36, Rich Felker <dalias@...c.org> wrote:
> >
> > On Thu, Jun 28, 2018 at 08:57:29PM +0300, Alexander Monakov wrote:
> > > Avoid saving/restoring the incoming argument by reusing memset return value.
> > > ---
> 
> Why not even though I m wondering if this saving/restoring really
> occurs/instruction really generated with last compilers.
> Prefer Alexander's version otherwise :-)

It necessarily has to because of ABI. Any register you could use to
save the value before making an external call is a register whose old
value you would have to save before using it, so no matter what you
do, something has to get spilled to the stack and thus a stack frame
has to be created.

Rich

Powered by blists - more mailing lists

Your e-mail address:

Powered by Openwall GNU/*/Linux - Powered by OpenVZ