RFR: 8349814: [leyden] Reduce uncommon traps in preload code [v8]

[Aleksey Shipilev]

On Tue, 1 Apr 2025 16:58:19 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Preload code is the C2 code we load very early, before it gets substituted by more advanced C2 code. We are seeing lots of uncommon traps from the preloaded code, though, which invalidates it too early. We can do precompile code without uncommon traps to alleviate this. 
>> 
>> Additional testing:
>>  - [x] Ad-hoc perf tests (see comment below)
>>  - [x] Linux x86_64 server fastdebug, `runtime/cds`
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Also a script

> I've fixed the CP pre-resolution bug. See [bd21267](https://github.com/openjdk/leyden/commit/bd212673822a21164fbf57b255005339d28ef509)

This is _AWESOME_. There are no uncommon traps from `ciTypeFlow` on `JavacBenchApp` anymore. It is visibly improving `JavacBenchApp` perf.

And this PR eliminates the rest of the (speculative) traps, so no uncommon traps from `AP` code in sight at all so far. I'll revert this PR back to integrateable form.

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PR Comment: https://git.openjdk.org/leyden/pull/38#issuecomment-2771416113