clang 3.2 RC2 miscompiles libgcc?
Stefan Farfeleder
stefanf at FreeBSD.org
Tue Jan 8 08:58:36 UTC 2013
On Tue, Jan 08, 2013 at 12:21:12AM +0100, Dimitry Andric wrote:
> On 2013-01-06 17:03, Stefan Farfeleder wrote:
> > On Sun, Jan 06, 2013 at 03:59:59PM +0100, Dimitry Andric wrote:
> ...
> > The bug also affects ports software, e.g., I also experienced strange
> > rtorrent segfaults that are now gone.
>
> Can you please try the attached patch, which is a very horrid, atrocious
> hack, and will only work for amd64. Then rebuild libgcc with clang, and
> please try if this fixes at least some of the crashes...
>
> This is at least the direction I'm looking at. It seems that in some
> cases with __builtin_eh_return(), llvm does not see that registers can
> be clobbered, and it doesn't save and restore them.
>
> After a lot of splitting up of unwind-dw2.c, I arrived at _Unwind_Resume
> which when compiled by clang caused the crashes, but when compiled by
> gcc ran OK.
Hi Dimitry,
your patch seems to work just fine. No crashes whatsoever so far. Thank
you.
Stefan
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