RFR: 8251462: Remove legacy compilation policy [v4]

[Vladimir Kozlov]

On Fri, 22 Jan 2021 20:17:24 GMT, Igor Veresov <iveresov at openjdk.org> wrote:

>> I don't think so:
>>> java -Xint -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -version
>> Java HotSpot(TM) 64-Bit Server VM warning: JVMCI Compiler disabled due to -Xint.
>> 
>>> java -Xint -XX:+UnlockExperimentalVMOptions -XX:+UseAOT -XX:+PrintAOT -version
>> Java HotSpot(TM) 64-Bit Server VM warning: -Xint is not compatible with AOT (switching AOT off)
>
> You're right. Perhaps I was overly defensive. It doesn't hurt though, less potential surprises in the future (as you correctly noticed those are used to make sure there are no nmethods produced by any other compiler but C1).
> Also you still can have a C1 and AOT combination.

Yes. You can have C1 in combination with AOT and JVMCI (hosted).
I looked on use cases for these 4 methods and it seems it will be hard to only use one.
Okay. Leave them as it is. May be add comments to explain why you needs these variants.

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PR: https://git.openjdk.java.net/jdk/pull/1985