RFR: 8160821: VarHandle accesses are penalized when argument conversion is required [v3]

[Per Minborg]

On Tue, 2 Dec 2025 17:24:41 GMT, Chen Liang <liach at openjdk.org> wrote:

>> src/java.base/share/classes/java/lang/invoke/VarHandle.java line 2036:
>> 
>>> 2034:             var constant = MethodHandleImpl.isCompileConstant(vh);
>>> 2035:             var cache = adaptedMh;
>>> 2036:             if (constant == MethodHandleImpl.CONSTANT_YES && cache != null) {
>> 
>> Rookie question: Is there multi-thread considerations here? How about visibility across threads?
>
> MethodHandle is immutable and can be safely published. So this is ok.

I meant that even though objects are immutable, plain semantics might not always do. 

Reference: https://shipilev.net/blog/2014/safe-public-construction/

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PR Review Comment: https://git.openjdk.org/jdk/pull/28585#discussion_r2584535309