RFR: 8365512: Replace -Xcomp with -Xmixed for AOT assembly phase [v2]

[Aleksey Shipilev]

On Thu, 14 Aug 2025 13:54:27 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> When debugging AOT code generation in Leyden repo I noticed that AOT JIT compilations are serial with -Xcomp even so we create a lot of compiler threads to speed up. It is because -Xcomp enforce blocking compilation and only one thread submits AOT compilations. Also -Xcomp triggers a lot more other, not AOT, compilations which we don't need during assembly phase.
>> 
>> I suggest to replace -Xcomp with -Xmixed for AOT assembly phase.
>> 
>> I want to push it into mainline first because in mainline we don't even do AOT compilation yet.
>> 
>> This should speed up AOT testing with -Xcomp.
>> 
>> Tested tier1-6,8,10 (-rt)
>
> Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update comment

Looks good!

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26767#pullrequestreview-3120726121