[LLVMdev] [cfe-dev] Address sanitizer regression test failures for PPC64 targets

[Samuel F Antao]

Hi Hal,

No, the issue is still unresolved. Alexander Potapenko added Kostya to the
thread who seems to have authored the code that is causing the failure in
big-endian machines. I didn't get any feedback so far. I'd be happy to help
solve the issue but I didn't have the time to improve my understanding of
the sanitizer. There are several places in the sanitizer that are encoding
different information in memory through aliasing pointers so it is not
straightforward to me what the impact of fixing this particular endianess
problem is for other components of the sanitizer...

Thanks,
Samuel

2014-10-01 13:30 GMT-04:00 Hal Finkel <hfinkel at anl.gov>:

> Samuel,
>
> Was this ever resolved?
>
>  -Hal
>
> ----- Original Message -----
> > From: "Samuel F Antao" <sfantao at us.ibm.com>
> > To: "will schmidt" <will_schmidt at vnet.ibm.com>
> > Cc: "Clang Developers List" <cfe-dev at cs.uiuc.edu>, "LLVM Dev" <
> llvmdev at cs.uiuc.edu>
> > Sent: Friday, September 26, 2014 10:40:06 AM
> > Subject: Re: [LLVMdev] [cfe-dev] Address sanitizer regression test
> failures for PPC64 targets
> >
> >
> >
> >
> > Hi Will,
> >
> > Do the sanitizer tests work for you with gcc 4.9? I was using clang
> > 3.4.2 and started using clang 3.5.0. For both versions, I configured
> > clang to use the gcc 4.8.2 tooIchain.
> >
> > My understanding is that the compiler was not the problem but an
> > endianess issue in the sanitizer implementation that was causing
> > memory to get corrupted. The different versions of compiler just
> > caused the memory corruption to affect different ranges, causing
> > some tests that were not working to start working and vice-versa.
> >
> > I identified one of the places with the endianess issue in my
> > previous email. I'm unsure whether there are other places in the
> > code that only work for little endian.
> >
> > Thanks,
> > Samuel
> >
> > Inactive hide details for Will Schmidt ---09/26/2014 11:25:23 AM---On
> > Mon, 2014-09-08 at 22:00 -0400, Samuel F Antao wrote: > AWill
> > Schmidt ---09/26/2014 11:25:23 AM---On Mon, 2014-09-08 at 22:00
> > -0400, Samuel F Antao wrote: > Alexey, Alexander,
> >
> > From: Will Schmidt <will_schmidt at vnet.ibm.com>
> > To: Samuel F Antao/Watson/IBM at IBMUS
> > Cc: Alexander Potapenko <glider at google.com>, Clang Developers List
> > <cfe-dev at cs.uiuc.edu>, LLVM Dev <llvmdev at cs.uiuc.edu>
> > Date: 09/26/2014 11:25 AM
> > Subject: Re: [LLVMdev] [cfe-dev] Address sanitizer regression test
> > failures for PPC64 targets
> >
> >
> >
> >
> > On Mon, 2014-09-08 at 22:00 -0400, Samuel F Antao wrote:
> > > Alexey, Alexander,
> > >
> > > Thanks for the suggestions. I tried removing the flag SA_NODEFER
> > > but
> > > it didn't do any good... I have been digging into the problem with
> > > the
> > > null_deref test today but I was unable to clearly identify the
> > > problem. I suspect that it was either a bug with the calling
> > > convention/unwinding that lead to the flags() pointer to get
> > > corrupted. It is also possible that it was related with endianess
> > > issues caused by some bug in the pointer arithmetic inserted by the
> > > sanitizer code (there are many type and bit casts which makes hard
> > > to
> > > follow the
> >
> > > references). I decided to upgrade the compiler I was using to build
> > > clang which made the problem with this testcase to go away (!).
> >
> > Hi Samuel,
> > Which compiler versions were you using before/after ? At the moment,
> > I'm building with a gcc 4.9 snapshot, but can switch to something
> > newer
> > if you had a recommendation.
> >
> > Thanks,
> > -Will
> >
> >
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20141001/b567aa3f/attachment.html>