RFR: 8315585: Optimization for decimal to string [v7]

[Claes Redestad]

On Mon, 16 Oct 2023 15:00:42 GMT, Shaojin Wen <duke at openjdk.org> wrote:

>> I submitted PR #15555 before, and there were too many changes. I split it into multiple PRs with small changes. This one is one of them.
>> 
>> this PR removed the duplicate code for getChars in BigDecimal#StringBuilderHelper, i also make performance faster.
>> Please review and don't hesitate to critique my approach and patch.
>
> Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use StringConcatFactory.makeConcatWithConstants

Maybe, maybe not: it would require a bit of additional code (one method per class; a new cache for performant bootstrapping), and might cause a surprising increase in classes generated during startup/warmup so we need to look carefully at that.

Either way that's out of scope for this PR. Altering `StringConcatFactory` as per #16244 is a reasonable initial follow-up here, with no or only very limited downsides AFAICT.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/16006#issuecomment-1768639320