RFR: 8336856: Optimize String Concat [v35]

[Shaojin Wen]

On Tue, 6 Aug 2024 23:41:09 GMT, Shaojin Wen <duke at openjdk.org> wrote:

>> This PR implements the same algorithm as the current generateMHInlineCopy based on bytecode to improve startup performance.
>
> Shaojin Wen has updated the pull request incrementally with six additional commits since the last revision:
> 
>  - checkOverflow
>  - highArity default 0
>  - use MethodTypeDesc instead of MethodType
>  - inlineThreshold parameter
>  - use more idiomatic class-file API
>  - rename SimpleStringBuilderStrategy to InlineHiddenClassStrategy

1. `refactor to not generate coderArgs unless needed. ` Is this what you want?
https://github.com/wenshao/jdk/commit/d64552e247beca3f3241f20d5147ad62250dd06b

2. concatArgs still uses MethodType. There is no extra transformation here, so we will not change it for now.

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PR Comment: https://git.openjdk.org/jdk/pull/20273#issuecomment-2272351590