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

[David Holmes]

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.

Is the current use of `-Xint` documented? I'm not seeing how you are communicating this change to the user. To be honest this seems like it is aimed at Leyden, and as such probably belongs over there rather than in mainline.

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PR Review: https://git.openjdk.org/jdk/pull/16233#pullrequestreview-1684291313