On Wed, 1 Sep 2021 01:05:32 GMT, Mandy Chung <mch...@openjdk.org> wrote:
>> This reimplements core reflection with method handles. >> >> For `Constructor::newInstance` and `Method::invoke`, the new implementation >> uses `MethodHandle`. For `Field` accessor, the new implementation uses >> `VarHandle`. For the first few invocations of one of these reflective >> methods on a specific reflective object we invoke the corresponding method >> handle directly. After that we spin a dynamic bytecode stub defined in a >> hidden class which loads the target `MethodHandle` or `VarHandle` from its >> class data as a dynamically computed constant. Loading the method handle >> from a constant allows JIT to inline the method-handle invocation in order >> to achieve good performance. >> >> The VM's native reflection methods are needed during early startup, before >> the method-handle mechanism is initialized. That happens soon after >> System::initPhase1 and before System::initPhase2, after which we switch to >> using method handles exclusively. >> >> The core reflection and method handle implementation are updated to handle >> chained caller-sensitive method calls [1] properly. A caller-sensitive >> method can define with a caller-sensitive adapter method that will take an >> additional caller class parameter and the adapter method will be annotated >> with `@CallerSensitiveAdapter` for better auditing. See the detailed >> description from [2]. >> >> Ran tier1-tier8 tests. >> >> [1] https://bugs.openjdk.java.net/browse/JDK-8013527 >> [2] >> https://bugs.openjdk.java.net/browse/JDK-8271820?focusedCommentId=14439430&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14439430 > > Mandy Chung has updated the pull request incrementally with one additional > commit since the last revision: > > minor cleanup and more test case. Hi Mandy, Yes, you had exactly the same thoughts as me! So this improves the "Var" case for fields. I also ran tests on my PC with your vh-mh patch on top and here are visualized results (combined with previous results): jdk18+9 vs. mandy: https://jmh.morethan.io/?gists=7b2399cea71d12dfd3434701ddeed026,80203847700b9ab8baeb346a02efc804 jdk18+9 vs. peter: https://jmh.morethan.io/?gists=7b2399cea71d12dfd3434701ddeed026,b11842fbd48ebbd9234251fded50d52e jdk18+9 vs. peter+vh2mh: https://jmh.morethan.io/?gists=7b2399cea71d12dfd3434701ddeed026,2a61a99909415f9e0ab53b125628b11d mandy vs. peter: https://jmh.morethan.io/?gists=80203847700b9ab8baeb346a02efc804,b11842fbd48ebbd9234251fded50d52e mandy vs. peter+vh2mh: https://jmh.morethan.io/?gists=80203847700b9ab8baeb346a02efc804,2a61a99909415f9e0ab53b125628b11d peter vs. peter+vh2mh: https://jmh.morethan.io/?gists=b11842fbd48ebbd9234251fded50d52e,2a61a99909415f9e0ab53b125628b11d ------------- PR: https://git.openjdk.java.net/jdk/pull/5027
