From: "Mark Kettenis" <mark.kettenis@xs4all.nl>
To: "Andrew Haley" <aph@redhat.com>
Cc: "Ian Lance Taylor" <iant@google.com>,
"Mark Kettenis" <mark.kettenis@xs4all.nl>,
"Jan Kratochvil" <jan.kratochvil@redhat.com>,
gcc@gcc.gnu.org, libc-alpha@sources.redhat.com,
gdb@sourceware.org, "Jakub Jelinek" <jakub@redhat.com>,
"Richard Henderson" <rth@redhat.com>
Subject: Re: Unwinding CFI gcc practice of assumed `same value' regs
Date: Tue, 12 Dec 2006 17:34:00 -0000 [thread overview]
Message-ID: <14038.82.92.89.47.1165944860.squirrel@webmail.xs4all.nl> (raw)
In-Reply-To: <17790.57726.696229.240657@zebedee.pink>
> Ian Lance Taylor writes:
> > Andrew Haley <aph@redhat.com> writes:
> >
> > > In practice, %ebp either points to a call frame -- not necessarily
> the
> > > most recent one -- or is null. I don't think that having an optional
> > > frame pointer mees you can use %ebp for anything random at all, but
> we
> > > need to make a clarification request of the ABI.
> >
> > I don't see that as feasible. If %ebp/%rbp may be used as a general
> > callee-saved register, then it can hold any value.
>
> Sure, we already know that, as has been clear. The question is *if*
> %rbp may be used as a general callee-saved register that can hold any
> value.
The amd64 ABI is specifically *designed* to allow this.
Mark
next prev parent reply other threads:[~2006-12-12 17:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-11 19:03 Jan Kratochvil
2006-12-11 22:40 ` Roland McGrath
2006-12-12 15:54 ` Jakub Jelinek
2006-12-12 13:55 ` Andrew Haley
2006-12-12 14:55 ` Mark Kettenis
2006-12-12 15:04 ` Andrew Haley
2006-12-12 15:21 ` Ulrich Drepper
2006-12-12 15:26 ` Andrew Haley
2006-12-12 15:39 ` Ulrich Drepper
2006-12-13 18:11 ` Michael Matz
2006-12-12 15:50 ` Jan Kratochvil
2006-12-12 16:19 ` Jakub Jelinek
2006-12-12 16:55 ` Ian Lance Taylor
2006-12-12 17:06 ` Andrew Haley
2006-12-12 17:34 ` Mark Kettenis [this message]
2006-12-13 18:02 ` Michael Matz
2006-12-13 18:10 ` Michael Matz
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