RFR: 8305753: Allow JIT compilation for -Xshare:dump

[Calvin Cheung]

On Wed, 18 Oct 2023 05:43:11 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> This RFE makes it possible for the user to enable the JIT compiler during the CDS dump by specifying `-Xshare:dump -Xmixed`
> 
> By default, `-Xshare:dump` runs with `-Xint`. This maintains the previous behavior.
> 
> Which mode to use?
> 
> - Dumping in `-Xint` mode is faster when the classlist is small. `-Xint` is also required for deterministic dumping (compiler threads can change the order of the archived object).
> 
> - However, dumping in `-Xmixed` mode is faster when the class list is larger. We also need to run the compiler in Leyden so that we can generate the CDS archive and AOT code at the same time.
> 
> 
> Tested with tiers 1-4 and builds-tier5.

Changes seem fine.
Just a suggestion on the log message.
Also, please file a doc subtask if you think it needs to be documented in the release note.

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Marked as reviewed by ccheung (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16233#pullrequestreview-1686056818