RFR: 8286669: Replace MethodHandle specialization with ASM in mainline [v3]

[Rémi Forax]

On Mon, 16 May 2022 17:40:41 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Hi,
>> 
>> This PR brings over commits from the panama-foreign repo. These commits mostly pertain to the switch to ASM and away from MethodHandle combinators for the binding recipe specialization. But, there is one more commit which adds freeing of downcall stubs, since those changes were mostly Java as well.
>> 
>> Thanks,
>> Jorn
>> 
>> Testing: `run-test-jdk_foreign` with `-Dgenerator.sample.factor=-1` on Windows and Linux.
>
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> 
>   BootstrapMethodError -> ExceptionInInitializerError

src/java.base/share/classes/jdk/internal/foreign/abi/BindingSpecializer.java line 157:

> 155:     }
> 156: 
> 157:     static MethodHandle doSpecialize(MethodHandle leafHandle, CallingSequence callingSequence, ABIDescriptor abi) {

I think thise method should be split in to, one version for the upcall, one for the downcall, i do not see the point of merging the two codes.

src/java.base/share/classes/jdk/internal/foreign/abi/BindingSpecializer.java line 816:

> 814:             return;
> 815:         }
> 816:         if (con instanceof Integer) {

those can use the instanceof + type pattern

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PR: https://git.openjdk.java.net/jdk/pull/8685