RFR: JDK-8301460: Clean up LambdaForm to reference BasicType enums directly [v2]

[Mandy Chung]

On Tue, 14 Feb 2023 11:16:26 GMT, Sergey Tsypanov <stsypanov at openjdk.org> wrote:

>> Mandy Chung has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8301460
>>  - further clean up
>>  - JDK-8301460: Code in LambdaForm.java still refers to resolved JDK-8161245
>
> src/java.base/share/classes/java/lang/invoke/BoundMethodHandle.java line 368:
> 
>> 366:             SpeciesData sd = extensions[typeNum];
>> 367:             if (sd != null)  return sd;
>> 368:             sd = SPECIALIZER.findSpecies(key() + basicType.basicTypeChar());
> 
> As soon as this is `java.base` I suggest to replace `key() + basicType.basicTypeChar()` with `key().concat(String.valueOf(basicType.basicTypeChar()))` to prevent `StringBuilder` allocation and `append()` chaining.

There are only 5 elements in `extensions` arrays for 5 `BasicType`.  I don't think this overhead is significant.

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PR: https://git.openjdk.org/jdk/pull/12546