Debugging NPE during CanonicalizerPhase

[Andreas Woess]

Looks like a frame slot field in one of your nodes was null at compile
time and read as a constant value. I'll have a look at your code tomorrow.

We'll add better checks soon.

- andreas

On 07.08.2013 00:35, Stefan Marr wrote:
> Hi Thomas:
>
> On 06 Aug 2013, at 08:56, Thomas Wuerthinger <thomas.wuerthinger at oracle.com> wrote:
>
>> Can you upload the IGV graph that is produced by the -G:+DumpOnError flag? You should have "./mx.sh igv" running in parallel and then export the graph as an XML file. Also, what is your stack trace?
> Well, I would like to, but the NPE getting into the way…
>
> Here the two stack traces, once with and once without igv:
>
> http://soft.vub.ac.be/~smarr/downloads/truffle/error-with-igv.txt
> http://soft.vub.ac.be/~smarr/downloads/truffle/error-without-igv.txt
>
> That's the result with the very latest code from today.
> Invocation looks like this:
> ./mx.sh --vm server --debug build debug && ./mx.sh --debug --vm server vm -G:+DumpOnError -Xbootclasspath/a:../som/build/classes som.vm.Universe -cp ../som/Smalltalk ../som/Examples/Benchmarks/Loop.som
>
> So far, I was only able to confirm that the null constant object really appears only in the CanonicalizerPhase.
> I added checks on the whole graph for everything that happens before the pass.
>
> One question Michael had, and that I investigate is whether there was anything related to TruffleSOM, and I think, the first null constant that was a problem was actually not directly related to my code. But I haven't had the chance to investigate further yet.
>
> Thanks
> Stefan
>
> PS: TruffleSOM can be build and tested like this:
>
>   $ git clone https://github.com/smarr/TruffleSOM.git som
>   $ cd som
>   $ ant test
>