RFR: 8271820: Implementation of JEP 416: Reimplement Core Reflection with Method Handle [v13]

[Mandy Chung]

On Wed, 13 Oct 2021 23:53:17 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Minor cleanup.  Improve javadoc in CallerSensitiveAdapter
>
> src/java.base/share/classes/jdk/internal/reflect/DirectMethodHandleAccessor.java line 86:
> 
>> 84:     }
>> 85: 
>> 86:     private static final int PARAM_COUNT_MASK = 0x00FF;
> 
> Is this packing logic required? I get it that it saves footprint - but then you have to always unmask bits to get the argument count (see invoke and other places). If you keep this, it might be worth documenting what the bit layout is supposed to be?

It's not driven by performance data.   It's part of Peter's contribution.   I also prefer it without the packing.   I propose to keep the parameter count as a separate variable and examine it when there is footprint issue.

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PR: https://git.openjdk.java.net/jdk/pull/5027