RFR: 8258961: devirtualize SafePointNode::jvms() and hide out set_jvms() [v2]

[Xin Liu]

On Tue, 5 Jan 2021 10:10:57 GMT, Xin Liu <xliu at openjdk.org> wrote:

>> src/hotspot/share/runtime/vmStructs.cpp line 945:
>> 
>>> 943:                                                                                                                                      \
>>> 944:   c2_nonstatic_field(SafePointNode,            _jvms,                                         JVMState* const)                       \
>>> 945:                                                                                                                                      \
>> 
>> Don't remove it. It is referenced from HotSpot Servicability agent:
>> https://github.com/openjdk/jdk/blob/master/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/opto/SafePointNode.java#L45
>
> Thank you for pointing out this.  I wasn't aware of this agent thing. 
> It turns out I can neither move SafePointNode::_jvms to the protected zone nor take off its const qualifier. 
> so I revert my changes except removing "virtual" for the SafePointNode::jvms().

I reverted files which need to update copyright years.

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PR: https://git.openjdk.java.net/jdk/pull/1899