From owner-freebsd-hackers@FreeBSD.ORG  Fri Dec  9 20:10:40 2011
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Date: Fri, 9 Dec 2011 15:10:38 -0500
Message-ID: <CAFMmRNwt62NDhan72+MVFw1iYswP2ixpKMyKnMCnd_KNK0zVbw@mail.gmail.com>
From: Ryan Stone <rysto32@gmail.com>
To: Gleb Kurtsou <gleb.kurtsou@gmail.com>
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Cc: mdf@freebsd.org, freebsd-hackers@freebsd.org, Piotr Nowak <pn@semihalf.com>,
	Rafal Jaworowski <raj@semihalf.com>,
	Nathan Whitehorn <nwhitehorn@freebsd.org>,
	Arnaud Lacombe <lacombar@gmail.com>
Subject: Re: gcc 4.2 miscompilation with -O2 -fno-omit-frame-pointer on amd64
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On Fri, Dec 9, 2011 at 1:15 PM, Gleb Kurtsou <gleb.kurtsou@gmail.com> wrote:
> -fno-omit-frame-pointer is there for kernel debugger to be able to
> generate backtraces.

It's also needed by the DTrace stack() action, hwpmc callchain capture
and stack(9).  Disabling it as anything other than a very short-term
bandaid is a non-starter.