clang: -mno-omit-leaf-frame-pointer

[Dimitry Andric]

On Mar 30, 2013, at 09:10, Andriy Gapon <avg at 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=9825


> 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.
> 
> 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.