On Mon, 1 May 2023 14:56:27 GMT, Chen Liang <li...@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 implements proxies with one hidden class for each requested interface >> and replaced WrapperInstance inheritance with a check to the class data. >> This can avoid unexpected passing of `instanceof`, and avoids the nasty >> problem of exporting a JDK interface to a dynamic module to ensure access. >> 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 generated hidden classes has call performance on par with >> those of lambda expressions; the creation performance is slightly less than >> that of LambdaMetafactory: >> https://jmh.morethan.io/?gist=fcb946d83ee4ac7386901795ca49b224 >> >> Additionally, an obsolete `ProxyForMethodHandle` test was removed, for it's >> no longer applicable. Tests in `jdk/java/lang/invoke` and >> `jdk/java/lang/reflect` pass. >> >> [^1]: single abstract method > > Chen Liang has updated the pull request with a new target base due to a merge > or a rebase. The incremental webrev excludes the unrelated changes brought in > by the merge/rebase. The pull request contains 24 additional commits since > the last revision: > > - Renames > - Merge branch 'master' into explore/mhp-iface > - Consolidate iteration over public methods > - Define MH proxy class in a dynamic module > - Fix test that depend on WrapperInstance > - Require an original lookup in constructor arguments to prevent unintended > instantiation > - pass interface info via condy, > drop explicit ea flags > initialize benchmark work variable randomly > benchmarks just need 1 fork > - Nuke WrapperInstance > - Merge branch 'master' into explore/mhp-iface > - Whitespace, cleanup, rename benchmarks to be informative > - ... and 14 more: https://git.openjdk.org/jdk/compare/a52adfb8...f5d0ef0a 1. About moving the checker method to another existing class: Security Manager denies calls to conditionally-exported java.base internal packages, should I spin a utility class in a new module on initialization and export that module to the generated proxy classes, or pass a live methodhandle to the validation method to the class? 2. Another question for Project Leyden: does it aim to further reduce the number of LambdaForm-compiled invoker classes generated as well, especially customized LambdaForms? I think I will try add a benchmark that measures the cold-start and creation performance for the proxies, especially for the shared-class implementation; at least the proxy-based implementation has negligible creation performance compared to the dedicated-class implementation last I tested. Also as a side note, class definition does bring a huge creation-time overhead: it takes 25000 ns to create a dedicated instance, but only 20ns to create a shared instance. The dedicated-class implementation has no advantage besides the blazingly-fast invocation performance for non-constant instances. ------------- PR Comment: https://git.openjdk.org/jdk/pull/13197#issuecomment-1532146903
