RFR: 6983726: Reimplement MethodHandleProxies.asInterfaceInstance [v14]
Chen Liang
liach at openjdk.org
Sun May 7 03:43:28 UTC 2023
> 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 Additionally, an obsolete `ProxyForMethodHandle` test was removed, for it's no longer applicable.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 incrementally with one additional commit since the last revision:
stupid faults
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/13197/files
- new: https://git.openjdk.org/jdk/pull/13197/files/8b971172..af36da3c
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=13197&range=13
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=13197&range=12-13
Stats: 208 lines in 3 files changed: 1 ins; 16 del; 191 mod
Patch: https://git.openjdk.org/jdk/pull/13197.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/13197/head:pull/13197
PR: https://git.openjdk.org/jdk/pull/13197
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