Jenkins build is still unstable: FreeBSD_HEAD-tests2 #867

[Dimitry Andric]

On 22 Mar 2015, at 23:11, Garrett Cooper <yaneurabeya at gmail.com> wrote:
> 
> On Mar 22, 2015, at 15:09, Dimitry Andric <dim at FreeBSD.org> wrote:
> 
>> On 22 Mar 2015, at 23:04, Garrett Cooper <yaneurabeya at gmail.com> wrote:
>>> 
>>> On Mar 22, 2015, at 15:01, Craig Rodrigues <rodrigc at FreeBSD.org> wrote:
>>> 
>>> ...
>>> 
>>>> OK, converting expr.y to use unsigned integers would require a bit of work.
>>>> 
>>>> Can you commit your patch to the Makefile?  It fixes the problem for now.
>>> 
>>> +1
>>> 
>>> I’d still like to know why clang 3.5 doesn’t have this behavior though — there might be other potential issues lurking around that need to be solved (either here, in ports, or both).
>> 
>> Because this version optimizes better around undefined behavior.  There
>> are most likely many issues lurking around, and most certainly in ports.
>> 
>> I would recommend using UBSan to tackle this kind of thing.
> 
> I hope this got a ports tinderbox run first…

It is called an "exp-run" in ports land, but that only really tests
whether ports *build* successfully.  For most ports, there is no good
way of testing them, certainly not if they don't have their own testing
facilities.

That said, I have built quite a number of ports with 3.6.0, even before
the import, and saw zero problems until now.  Then again, I'm just one
user, and that is a very low sample size. ;)

I don't expect a great many problems with integer wrapping though.  You
have to realize that quite a lot of open source projects already went
through this phase, when gcc started optimizing integer wrapping a few
years ago.  We are just slowly catching up.


> Adding UBSan to tinderbox runs for toolchain upgrades [in the future] might be a good idea.

Maybe, but please note that both ASan and UBSan are still beta-ish under
FreeBSD, there will most likely be bumps along the road.  Any bug
reports in that area are welcome.

-Dimitry

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