RFR: 6983726: Reimplement MethodHandleProxies.asInterfaceInstance [v16]

[Chen Liang]

On Sun, 7 May 2023 13:34:54 GMT, Chen Liang <liach at openjdk.org> wrote:

>> As John Rose has pointed out in this issue, the current j.l.r.Proxy based implementation of MethodHandleProxies.asInterface has a few issues:
>> 1. Exposes too much information via Proxy supertype (and WrapperInstance interface)
>> 2. Does not allow future expansion to support SAM[^1] abstract classes
>> 3. Slow (in fact, very slow)
>> 
>> This patch addresses all 3 problems:
>> 1. It updates the WrapperInstance methods to take an `Empty` to avoid method clashes
>> 2. This patch obtains already generated classes from a ClassValue by the requested interface type; the ClassValue can later be updated to compute implementation generation for abstract classes as well.
>> 3. This patch's faster than old implementation in general.
>> 
>> 
>> Benchmark                                                          Mode  Cnt      Score      Error  Units
>> MethodHandleProxiesAsIFInstance.baselineAllocCompute               avgt   15      1.483 ±    0.025  ns/op
>> MethodHandleProxiesAsIFInstance.baselineCompute                    avgt   15      0.264 ±    0.006  ns/op
>> MethodHandleProxiesAsIFInstance.testCall                           avgt   15      1.773 ±    0.040  ns/op
>> MethodHandleProxiesAsIFInstance.testCreate                         avgt   15     16.754 ±    0.411  ns/op
>> MethodHandleProxiesAsIFInstance.testCreateCall                     avgt   15     19.609 ±    1.598  ns/op
>> MethodHandleProxiesAsIFInstanceCall.callDoable                     avgt   15      0.424 ±    0.024  ns/op
>> MethodHandleProxiesAsIFInstanceCall.callHandle                     avgt   15      1.936 ±    0.008  ns/op
>> MethodHandleProxiesAsIFInstanceCall.callInterfaceInstance          avgt   15      1.766 ±    0.014  ns/op
>> MethodHandleProxiesAsIFInstanceCall.callLambda                     avgt   15      0.414 ±    0.005  ns/op
>> MethodHandleProxiesAsIFInstanceCall.constantDoable                 avgt   15      0.271 ±    0.006  ns/op
>> MethodHandleProxiesAsIFInstanceCall.constantHandle                 avgt   15      0.263 ±    0.004  ns/op
>> MethodHandleProxiesAsIFInstanceCall.constantInterfaceInstance      avgt   15      0.266 ±    0.005  ns/op
>> MethodHandleProxiesAsIFInstanceCall.constantLambda                 avgt   15      0.262 ±    0.003  ns/op
>> MethodHandleProxiesAsIFInstanceCall.direct                         avgt   15      0.264 ±    0.005  ns/op
>> MethodHandleProxiesAsIFInstanceCreate.createCallInterfaceInstance  avgt   15     18.000 ±    0.181  ns/op
>> MethodHandleProxiesAsIFInstanceCreat...
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove assertion, no longer true with teleport definition in MHP

About the security manager: the proposal to change SecurityManager to permit exporting the internal API packages would change the specification of `SecurityManger::checkPackageAccess`. Should I touch that in this patch and potentially require CSR review about SecurityManager changes, or should I go back to the original Proxy-like checks?

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PR Comment: https://git.openjdk.org/jdk/pull/13197#issuecomment-1572243080