JDK 9 rampdown and a plea for mercy

[Uwe Schindler]

Thanks Andrew,

I already sent a similar e-mail about Lucene to the jdk9-dev and hotspot-dev lists... I hope we can fix this! PLEASE, PLEASE! :-)

Uwe

-----
Uwe Schindler
uschindler at apache.org 
ASF Member, Apache Lucene PMC / Committer
Bremen, Germany
http://lucene.apache.org/

> -----Original Message-----
> From: hotspot-dev [mailto:hotspot-dev-bounces at openjdk.java.net] On
> Behalf Of Andrew Haley
> Sent: Friday, March 10, 2017 3:56 PM
> To: John Rose <john.r.rose at oracle.com>; Vladimir Kozlov
> <vladimir.kozlov at oracle.com>
> Cc: hotspot-dev Source Developers <hotspot-dev at openjdk.java.net>
> Subject: JDK 9 rampdown and a plea for mercy
> 
> As you may remember, I did some work on ByteBuffers a couple of years
> ago.  At the time the generated code was sparklingly good, and I was
> happy the job was done well.  Yesterday I looked at the code we are
> generating in JDK9, and was horrified to see that it now is a steaming
> pile of ordure.  It might be, of course, that I am mistaken about it
> being better before, but I really don't think so: I wouldn't have let
> it go out like that.  I suppose it was just good luck (or a C2 bug)
> that great code was generated.
> 
> The full gory details are in
> https://bugs.openjdk.java.net/browse/JDK-8176513, but the bottom line
> is that unless this regression is fixed all my ByteBuffer work will
> have been for naught.
> 
> Roland has had a look at what is happening, and he thinks that this
> can be fixed fairly quickly: he already has a working patch.  Is there
> any way that we can get it in?
> 
> One thing for the future: we need to keep an eye on code quality
> regressions.  I'm not sure how, exactly.  And perhaps I need to
> remember that just because C2 generates good code today, it might not
> generate good code tomorrow.
> 
> Thanks,
> 
> Andrew.