RFR: 8335922: Incorrect @Stable usage of LambdaForm$Name.index [v3]

[Jorn Vernee]

On Mon, 15 Jul 2024 15:57:30 GMT, Chen Liang <liach at openjdk.org> wrote:

>> The `@Stable` on the `index` field is incorrect, as stable only avoids inlining `0`. Solution is to use bit flip on the actual index (and rename the field to `flippedIndex`), so we use -1 to -256 (mapping to 0 to 255) and 0 the default value is used as an unset indicator.
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Encapsulate offsetIndex, share computation result

The changes look good to me, but I wonder if we ever actually benefit from these fields being stable, since we always skip LF interpretation in practice.

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Marked as reviewed by jvernee (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20178#pullrequestreview-2178164865