New Xorg crashes when built with clang

[Gautam]

Hi,

I am running 9/stable with a clang world+kernel and also with all ports
built with clang where possible.

I am running xfce and when I click on the firefox launcher, X freezes --
I get a bizzare range of colours and it seems that the X server has
crashed. The machine is still responsive via the network, I am able to
ssh etc.

I finally isolated the culprit to x11-servers/xorg-server which works
fine when I build it with base gcc, but has this bad behaviour when I
build it with clang.

uname -a
FreeBSD mellon 9.0-STABLE FreeBSD 9.0-STABLE #0 r235508M: Thu May 17
12:07:49 IST 2012     root at mellon:/usr/obj/usr/src/sys/MYKERNEL  amd64

MYKERNEL only has ACPI_DEBUG enabled on top of GENERIC.

Please note that I am using the drm-all.13.7-stable9.1.patch on top of
r235508.

I have uploaded a tarball containing the required configuration files, logs
as
well as sysctl dumps.

http://www.execve.net/showcase/x.crash.18052012_01/xcrash.txz

$ tar Jtf xcrash.txz
clangports.conf                # ports configured with gcc go here
hw.dri.0.info_after.txt        # before the crash.
hw.dri.0.info_before.txt       # after the crash via another ssh conn
make.conf
messages                       # after dri.debug=3
pciconf-lvb.txt
src.conf
Xorg.0.log.old

I could not find a core file from Xorg, but the Xorg.log file does
indicate a SEGV. Any idea on this problem? Do let me know if any further
information is required; The problem is fully reproducible.

Thanks in advance!
Gautam