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Subject: Re: clang: -mno-omit-leaf-frame-pointer
From: Dimitry Andric <dim@FreeBSD.org>
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Date: Sat, 30 Mar 2013 20:42:52 +0100
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To: Andriy Gapon <avg@freebsd.org>
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On Mar 30, 2013, at 09:10, Andriy Gapon <avg@freebsd.org> wrote:
> It seems that, unlike gcc, for clang -fno-omit-frame-pointer does not =
imply
> -mno-omit-leaf-frame-pointer.  This is probably a bug.

Yes, this is indeed the case.  There is even a rather old unresolved PR
for it in LLVM's Bugzilla:

http://llvm.org/bugs/show_bug.cgi?id=3D9825


> Meanwhile I would like to propose the following amd64-specific patch.  =
Perhaps
> the same type of change would be useful for powerpc as well.

Most likely yes.


> I would like this change primarily for DTrace (fbt), but other
> debugging/profiling code may benefit from it as well.
>=20
> I chose to make -mno-omit-leaf-frame-pointer not conditional on clang, =
because
> with gcc it is just a nop (i.e. it doesn't hurt anything).

The patch looks good to me, please commit.