RFR: 8340280: Avoid calling MT.invokerType() when creating LambdaForms [v2]

[Chen Liang]

On Tue, 17 Sep 2024 22:28:17 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> This PR exploits the observation that in many of the cases where we call `methodType.invokerType()` we immediately translate it into a `Name[]` where the only effect is to create an array with an additional leading `BasicType.L_TYPE` argument. Only in a subset of cases will a corresponding `invokerType()` be created later to bind the MH to an invoker.
>> 
>> Providing methods to bypass the creationg of such transient, intermediary `MethodType` creation avoids excessive allocations and adding types to the MT interning table that quickly become stale.
>> 
>> Number of executed bytecode on a trivial HelloLambda application drops locally from ~517k to ~505k.
>
> Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove argumentsWithTrailingObjectArguments (only one use), handle the logic at callsite

src/java.base/share/classes/java/lang/invoke/DirectMethodHandle.java line 256:

> 254:         if (doesAlloc) {
> 255:             var ptypes = mtype.ptypes();
> 256:             var newPtypes = new Class<?>[ptypes.length + (doesAlloc ? 2 : 1)];

Suggestion:

            var newPtypes = new Class<?>[ptypes.length + 2];

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PR Review Comment: https://git.openjdk.org/jdk/pull/21035#discussion_r1764097518