> Implement a method handle combinator that can be used to synchronize on an
> object monitor while executing a given target method handle.
>
> The returned method handle behaves similar to the notional code:
>
>
> R adapter(Object lock, A... a) throws Throwable {
> synchronized (lock) {
> return body.invokeExact(a...);
> }
> }
>
>
> The lambda form is similar to existing ones: we box up all the arguments for
> the body handle, call a fallback function which synchronizes and invokes the
> body with the boxed argument, then the `Object` result is fed to an unboxing
> handle to unbox the result if needed.
>
> There's a corresponding intrinsic in `InvokerBytecodeGenerator` which
> replaces these three operations with `monitorEnter`/`monitorExit`
> instructions, direct argument/return value forwarding without (un)boxing, and
> the necessary exception handling which makes sure we unlock the lock again in
> case the body throws an exception. The generated code is similar to what
> javac generates.
>
> ---------
> - [x] I confirm that I make this contribution in accordance with the [OpenJDK
> Interim AI Policy](https://openjdk.org/legal/ai).
Jorn Vernee has updated the pull request incrementally with three additional
commits since the last revision:
- Fix typo
- Add lambdaform shape comment
- Add LF interpreter test + var args collector test + use asFixedArity
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/32817/files
- new: https://git.openjdk.org/jdk/pull/32817/files/0febce35..3dfd4c6d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=32817&range=02
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=32817&range=01-02
Stats: 40 lines in 3 files changed: 38 ins; 0 del; 2 mod
Patch: https://git.openjdk.org/jdk/pull/32817.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/32817/head:pull/32817
PR: https://git.openjdk.org/jdk/pull/32817
