RFR: 8350617: Improve MethodHandles.tableSwitch and remove intrinsicData

[Jorn Vernee]

On Tue, 4 Mar 2025 14:33:27 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> In that case, won't the root form be customized and the table switch names be inlined into the root form?
>
> The root would e.g. have a constant BMH pointing at a _shared_ tableSwitch LF. So, the BMH fields would be seen as constant as well, including the list of cases. The issue is that the bytecode of the tableSwitch BMH will not be using the intrinsic, since it's not customized itself, i.e. it will only have a single call site for all cases.

I think we could get around this by always wrapping the `tableSwitch` MH in an `exactInvoker`, which adds the customization check for its callee. It would mean we will also separately customize any tableSwitch MH that's part of a larger chain.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23763#discussion_r1979591207