[8u] RFR(XXS): 8165231: java.nio.Bits.unaligned() doesn't return true on ppc

[Sean Coffey]

Hi Volker,

The fix looks fine to me. Please add the '9-na' label to the bug report. 
Also add a suitable noreg- label. It would also be useful to link the 
issue to JDK-8158260

Approved for jdk8u-dev.

regards,
Sean.

On 13/09/2016 09:37, Volker Simonis wrote:
> Hi Alan, Sean,
>
> can we please get a review for this rather trivial change?
>
>> jira: https://bugs.openjdk.java.net/browse/JDK-8165231
>> webrev: http://cr.openjdk.java.net/~gromero/8165231/
> As outlined in Hiroshi's initial mail, we can not simply downport the
> solution used in jdk9 for querying the unaligned access support in nio
> because of differences in Unsafe. So this is a jsk8u-only change. But
> I think it is simple enough and doesn't affect any other platform
> except ppc to justify it.
>
> As nobody from the ppc porting team is jdk8u reviewer, I kindly ask
> you for a review and the permission to integrate into jdk8u.
>
> Thanks a lot and best regards,
> Volker
>
>
> On Thu, Sep 1, 2016 at 5:06 PM, Doerr, Martin <martin.doerr at sap.com> wrote:
>> Hi Hiroshi,
>>
>>
>>
>> thanks for providing a fix.
>>
>>
>>
>> The fix
>>
>> 8158260: PPC64: unaligned Unsafe.getInt can lead to the generation of
>> illegal instructions
>>
>> was downported to 8, so I think your change is good.
>>
>>
>>
>> Best regards,
>>
>> Martin
>>
>>
>>
>>
>>
>> From: Hiroshi H Horii [mailto:HORII at jp.ibm.com]
>> Sent: Donnerstag, 1. September 2016 16:27
>> To: jdk8u-dev at openjdk.java.net; ppc-aix-port-dev at openjdk.java.net
>> Cc: Gustavo Bueno Romero <gromero at br.ibm.com>; Volker Simonis
>> (volker.simonis at gmail.com) <volker.simonis at gmail.com>; Doerr, Martin
>> <martin.doerr at sap.com>
>> Subject: RFR(m): java.nio.Bits.unaligned() doesn't return true on ppc
>>
>>
>>
>> Dear all:
>>
>> Can I please request reviews for the following change?
>> This change was created for JDK 8.
>>
>> Some open sources (such as Spark 2.0) check java.nio.Bits.unaligned()
>> to recognize support of unaligned memory access in platform.
>> Though ppc64 and ppc64le support it, unaligned() returns false.
>>
>> In JDK 9, this method returns unalignedAccess() of jdk.internal.misc.Unsafe
>> that doesn't exist in JDK8.
>>
>> jira: https://bugs.openjdk.java.net/browse/JDK-8165231
>> webrev: http://cr.openjdk.java.net/~gromero/8165231/
>> (Due to my login issue to the cs.openjdk.java.net, Gustavo thankfully
>> created this webrev.)
>>
>> Regards,
>> Hiroshi
>> -----------------------
>> Hiroshi Horii, Ph.D.
>> IBM Research - Tokyo