[PATCH][Revised] Enable libsanitizer on darwin

[Jack Howarth]

On Wed, Nov 14, 2012 at 10:54:18AM -0800, Mike Stump wrote:
> On Nov 14, 2012, at 6:43 AM, Jack Howarth <howarth@bromo.med.uc.edu> wrote:
> >   The attached patch assumes that mach_override/mach_override.h
> > and mach_override/mach_override.c has been imported by the libsanitizer
> > maintainers for use by darwin.
> 
> So, the patches are a nice start.  Since we are in stage3, they need to go in, in a way that is suitable for release.  If the feature is expected to work (I think that's true) and if these patches don't yet work well enough (I don't have a take on wether this is the case or not), then as the patches go in, they need to go in with the feature off or disabled.  So, I'd like a person that understand s libsanitizer and what we need (what is suitable) for release to approve the patches.  If I do, I'd need to understand more than I do.  What we don't want, a half implementation that is worse than saying, unsupported.  I don't mind if the support isn't complete, yet, what is there works fine.

Mike,
    With Alexander Potapenko's proposed patch for interception/mach_override/mach_override.c...

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55289#c29

the use-after-free test case from http://code.google.com/p/address-sanitizer/wiki/AddressSanitizer now
passes without errors on both x86_64-apple-darwin12 and i386-apple-darwin10. So at the moment we
don't have any known issues. Hopefully we can get the missing interception/mach_override/mach_override.c
and interception/mach_override/mach_override.h files added soon along with the build patch so we can
start monitoring libsanitizer for other issues in mach_override.c.
           Jack