JDK 9 rampdown and a plea for mercy (original) (raw)

Uwe Schindler uschindler at apache.org
Fri Mar 10 18:22:55 UTC 2017

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.

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