RFR: 8264288: Performance issue with MethodHandle.asCollector [v3]

[Jorn Vernee]

On Mon, 5 Apr 2021 12:48:07 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   - Revert back to injected constructor handle
>>   - Add lambda form sharing
>>   - Add test case for collecting a custom class
>
> src/java.base/share/classes/java/lang/invoke/MethodHandleImpl.java line 1883:
> 
>> 1881: 
>> 1882:         MethodHandle newArray = MethodHandles.arrayConstructor(arrayType);
>> 1883:         MethodHandle storeFunc = ArrayAccessor.getAccessor(arrayType, ArrayAccess.SET);
> 
> I'd move `storeFunc` into `makeCollectorForm()` and use erased accessor there (`ArrayAccessor.OBJECT_ARRAY_SETTER`). 
> 
> (It is interesting that `OBJECT_ARRAY_SETTER` is `ARRAY_STORE` intrinsic.)

Done. I think it's also more obvious this way that the erased setter is being used. Good suggestion.

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PR: https://git.openjdk.java.net/jdk/pull/3306