RFR(S): 8158260: PPC64: unaligned Unsafe.getInt can lead to the generation of illegal instructions

Volker Simonis volker.simonis at gmail.com
Fri Jun 17 08:49:23 UTC 2016


can somebody please sponsor this change?

It's ppc64-only but I think I still need a sponsor because it also has
a jterg test included.

Thank you and best regards,

On Thu, Jun 16, 2016 at 11:02 AM, Lindenmaier, Goetz
<goetz.lindenmaier at sap.com> wrote:
> Hi Volker,
> I've looked at the change, it's fine.  Thanks for fixing this.
> Best regards,
>   Goetz.
>> -----Original Message-----
>> From: ppc-aix-port-dev [mailto:ppc-aix-port-dev-
>> bounces at openjdk.java.net] On Behalf Of Volker Simonis
>> Sent: Dienstag, 14. Juni 2016 20:12
>> To: hotspot compiler <hotspot-compiler-dev at openjdk.java.net>; ppc-aix-
>> port-dev at openjdk.java.net; aarch64-port-dev at openjdk.java.net
>> Cc: Hiroshi H Horii <HORII at jp.ibm.com>; Gustavo Romero
>> <gromero at linux.vnet.ibm.com>
>> Subject: RFR(S): 8158260: PPC64: unaligned Unsafe.getInt can lead to the
>> generation of illegal instructions
>> Hi,
>> can I please get a review for this small change which fixes a code
>> generation problem on ppc64:
>> http://cr.openjdk.java.net/~simonis/webrevs/2016/8158260/
>> https://bugs.openjdk.java.net/browse/JDK-8158260
>> In the case where we access an unaligned address trough Unsafe, we
>> could generate an illegal instruction because we didn't correctly
>> specify the memory operand of some match rules. The fix is trivial.
>> Although this change is ppc64-specific I think I need a sponsor
>> because the change contains a new regression test which is supposed to
>> run on all platforms.
>> On platforms where Unsafe.unalignedAccess() will return false (e.g.
>> Solaris/SPARC) this test will return immediately (and I've verified
>> that it works).
>> I've also added aarch64 to the list of recipients because on aarch64
>> Unsafe.unalignedAccess() is apparently supported and it would be nice
>> if somebody could check that the new regression test is indeed working
>> there.
>> @Hiroshi, Gustavo: could you please verify that this change is enough
>> to fix the initial problems you've observed when running Cassandra on
>> Linux/ppc64? The changes from ppc64.ad should easily apply to the
>> 8u-dev repository. Once we've got this into jdk9 I'll trigger a
>> downport request to get the fix into jdk8 as well.
>> Thank you and best regards,
>> Volker

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