RFR: 8307462: [REDO] VmObjectAlloc is not generated by intrinsics methods which allocate objects [v3]

[Serguei Spitsyn]

On Fri, 4 Aug 2023 19:45:56 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> The fix adds posting VmObjectAlloc events by Unsafe.allocateInstance(Class<?> cls). The previous attempt to post event directly from 'LibraryCallKit::inline_unsafe_allocate()' cause performance regression even if jvmti event is not enabled.  Some optimizations have been disabled just because possible usage and escaping of newly allocated  object.
>> So event posting is doing by returning to interpreter if events are enabled.
>> 
>> I verified that that performance (run locally only) of
>> org.renaissance.jdk.streams.JmhScrabble.runOperation
>> doesn't change if events are not enabled.
>> 
>> There might be other intrinsics like 'LibraryCallKit::inline_unsafe_newArray()' where VM allocate memory. I'm going to file separate issue to find and fix them.
>> 
>> Many thanks to Tobias H. for proposed solution.
>> 
>> Testing with all tiers.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   The too many deopts check should be first.

This looks okay to me.
It needs to be reviewed by someone from the compiler team.
Thanks,
Serguei

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Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15110#pullrequestreview-1563532886