[aarch64-port-dev ] RFR(T): 8226222: [JVMCI] Export AArch64 field VM_Version::_psr_info.dczid_el0

[Ningsheng Jian]

Hi,

Yes, I think it's OK for latest jdk, since Graal code will check the 
field presence before using the instruction.

I can do the push for Pengfei.

Thanks,
Ningsheng

On 6/19/19 12:55 AM, Vladimir Kozlov wrote:
> This is purely JVMCI changes for aarch64 code which is not present in JDK8u and is not requires in graal-jvmci-8.
> But GraalVM would support jdk11u soon where this code is present. My question was about to have versioned code in
> graal-jvmci for JDK 11u.
> 
> On other hand I am perfectly fine to have this change only in latest JDK (jdk 14). As Pengfei correctly pointed we would
> not do any Graal update in 11u.
> 
> Pengfei, to you need sponsor to push your changes?
> 
> Thanks,
> Vladmir
> 
> On 6/18/19 1:02 AM, Pengfei Li (Arm Technology China) wrote:
>> Hi,
>>
>>>> This looks fine to me. We can push it into jdk/jdk (which is jdk 14 now).
>>>> I am not sure where we should backport this. Doug, what do you think?
>>>
>>> I’m not familiar with the OpenJDK backport decision making process so I’m
>>> not exactly sure what you’re asking me.
>>
>> Thanks for your review.
>>
>> I just read the JDK Update Guidance[1] and JDK Release Process[2]. According to the rules, this patch should be backported only to jdk11u. But as this change is just a support of Graal compiler optimization and latest Graal code won't be synced with jdk11u any more,  I don't think we have the need to do the backport. On the other hand, the Graal compiler has the ability to check the existence of a given field and give up optimization if required field is not present. So I think there should be no compatibility issue between the Graal compiler and multiple JDK versions, even if we don't do the backport.
>>
>> [1] https://wiki.openjdk.java.net/display/JDKUpdates/JDK+Updates+Guidance
>> [2] http://openjdk.java.net/jeps/3
>>
>> --
>> Thanks,
>> Pengfei
>>