On Tue, 19 Nov 2024 14:23:58 GMT, Francesco Nigro <d...@openjdk.org> wrote:
>> When core reflection was migrated to be implemented by Method Handles, >> somehow, the method handles are not used for native methods, which are >> generally linkable by method handles. This causes significant performance >> regressions when reflecting native methods, even if their overrides may be >> non-native methods. This is evident in `Object.clone` and `Object.hashCode` >> as shown in the original report. >> >> I believe the blanket restriction previously placed on the native methods >> was because of signature polymorphic methods ([JLS >> 15.12.3](https://docs.oracle.com/javase/specs/jls/se23/html/jls-15.html#jls-15.12.3), >> [JVMS >> 2.9.3](https://docs.oracle.com/javase/specs/jvms/se23/html/jvms-2.html#jvms-2.9.3)) >> for MethodHandle and VarHandle; method handles do not link to the backing >> implementation that throws UOE while core reflection is required to do so. >> I have narrowed the restrictions to be specifically against these methods. >> >> Additionally, I cleaned up another check for invalid varargs flag. >> Together, I clarified the scenarios where native method accessors are used - >> all to bypass restrictions of java.lang.invoke. >> >> Testing: tier 1-5 green > > Sorry I didn't shared this before, but > https://gist.github.com/franz1981/4234195ca0168f3833023b610d91ddff > it should be the same issue (with a reproducer and a bit of analysis of > profiling data) > > FYI @viktorklang-ora @franz1981 Thanks—I was just curious as to the impact. 👍 /cc @liach ------------- PR Comment: https://git.openjdk.org/jdk/pull/22169#issuecomment-2486018937
