RFR: 8260605: Various java.lang.invoke cleanups [v5]

[Mandy Chung]

On Wed, 10 Mar 2021 16:34:39 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> - Remove unused code
>> - Inline and simplify the bootstrap method invocation code (remove pointless reboxing checks etc)
>> - Apply pattern matching to make some code more readable
>
> Claes Redestad 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 seven additional commits since the last revision:
> 
>  - Revert pattern matching changes covered by #2913
>  - Merge branch 'master' into invoke_cleanup
>  - Missing .values
>  - More cleanup, reduce allocations in InvokerBytecodeGenerator
>  - Missing outstanding changes
>  - Avoid unnecessary reboxing checks, inline and simplify class/mt invokes
>  - j.l.invoke cleanups

src/java.base/share/classes/java/lang/invoke/InvokerBytecodeGenerator.java line 342:

> 340:         setClassWriter(cw);
> 341:         cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER,
> 342:                 CLASS_PREFIX.concat(className), null, INVOKER_SUPER_NAME, null);

I prefer to use the existing common pattern using `+` as I believe this gain is in the noise.

src/java.base/share/classes/java/lang/invoke/BootstrapMethodInvoker.java line 151:

> 149:                     maybeReBoxElements(argv);
> 150:                     if (argv.length > 6) {
> 151:                         result = invokeWithManyArguments(bootstrapMethod, caller, name, type, argv);

it'd be cleaner to move this to the default case in line 162 and 174 instead of having this special if-block.

src/java.base/share/classes/java/lang/invoke/MethodType.java line 418:

> 416: 
> 417:     /**
> 418:      * Finds or creates a method type with additional parameter types.

`nptype` is never void but  what  about the check if `nptype` is not null?

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PR: https://git.openjdk.java.net/jdk/pull/2300