RFR: 6983726: Reimplement MethodHandleProxies.asInterfaceInstance [v16]

[Chen Liang]

On Fri, 26 May 2023 18:39:53 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> 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
>
> src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java line 209:
> 
>> 207:         if (intfc.isHidden())
>> 208:             throw newIllegalArgumentException("a hidden interface", intfc.getName());
>> 209:         if (!VM.isModuleSystemInited())
> 
> I don't expect this is needed.  I assume you are thinking for LMF to use this API?

Proxy-based impl had this check, so I'd assume MHP might want to defend against the same kind of improper usage.

> src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java line 433:
> 
>> 431: 
>> 432:     private static WrapperInstance asWrapperInstance(Object x) {
>> 433:         if (x instanceof WrapperInstance wrapperInstance)
> 
> In the previous version, `WrapperInstance` was not needed.  Instead it checks if the class is a  MHProxy class.   Did you run into any issue that you resurrect `WrapperInstance`?    Is it just because of accessing `ensureOriginalLookup`?

John Rose argues against using class data for Leyden. Since class data is the only known way to defend against user-manufactured annotations, I switched back to an extra wrapper interface. This approach also requires the Class loading checks since the interface is not unconditionally exported and fails security manager.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13197#discussion_r1207350363
PR Review Comment: https://git.openjdk.org/jdk/pull/13197#discussion_r1207349212