[cfe-commits] [PATCH] Fix random crasher

[Richard Smith]

Yes, a reduced testcase would be very useful.

On Wed, Jul 18, 2012 at 5:27 PM, Robinson, Paul
<Paul.Robinson at am.sony.com>wrote:

>  Thanks!
>
>
>
> I am not familiar with valgrind, but I suppose I could learn, if
>
> there is still interest in a test case that triggers it.
>
> --paulr
>
>
>  ------------------------------
> *From:* metafoo at gmail.com [metafoo at gmail.com] on behalf of Richard Smith [
> richard at metafoo.co.uk]
> *Sent:* Wednesday, July 18, 2012 4:54 PM
> *To:* Robinson, Paul
> *Cc:* cfe-commits at cs.uiuc.edu
> *Subject:* Re: [cfe-commits] [PATCH] Fix random crasher
>
>   On Wed, Jul 18, 2012 at 4:51 PM, Richard Smith <richard at metafoo.co.uk>wrote:
>
>>  On Wed, Jul 18, 2012 at 3:55 PM, Robinson, Paul <
>> Paul.Robinson at am.sony.com> wrote:
>>
>>> Guard use of a possibly uninitialized field.
>>>
>>> This was causing very unpredictable compiler crashes. I have not
>>> provided a test because even our most reliable reproducer still failed
>>> less than 10% of the time.
>>>
>>> I really really really don't like sometimes-uninitialized fields
>>> guarded by flags. It is not a robust practice and took us a couple of
>>> weeks of poking at it to find the root cause. But it is how the rest
>>> of SemaOverload handles this field, so we fixed it using the
>>> prevailing practice in the module.
>>>
>>
>>   Do you know where the uninitialized OverloadCandidate is coming from?
>> The only place I can see one being created is in
>> OverloadCandidateSet::addCandidate, which says:
>>
>>        Candidates.push_back(OverloadCandidate());
>>
>>  This zero-initializes the OverloadCandidate object.
>>
>
> I've checked in a variant on your change in r160470: it seems correct and
> appropriate even if FailureKind is always initialized, since we were
> previously implicitly and accidentally relying on ovl_fail_bad_deduction
> being nonzero.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20120718/aa2ad0e0/attachment.html>