On Tue, 6 Sep 2022 16:47:03 GMT, Ioi Lam <ik...@openjdk.org> wrote:
> Have you tested with method references? Two references to the same method
> will result in a single `JVM_CONSTANT_InvokeDynamic` constant pool entry in
> the classfile, but it's invoked by two callsites. As a result, two different
> lambda proxy classes will be generated, as the JVMS requires the
> invokedynamic resolution to be per callsite, not per constantpool entry.
>
> ```
> public class ShareBSM {
> public static void main(String args[]) {
> doit1(ShareBSM::func);
> doit2(ShareBSM::func);
> }
> static void func() { Thread.dumpStack(); }
> static void doit1(Runnable r) { r.run(); }
> static void doit2(Runnable r) { r.run(); }
> }
> ```
>
> Here's the output:
>
> ```
> $ java -cp . -XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames ShareBSM
> java.lang.Exception: Stack trace
> at java.base/java.lang.Thread.dumpStack(Thread.java:1380)
> at ShareBSM.func(ShareBSM.java:8)
> at ShareBSM$$Lambda$1/0x0000000800c009f0.run(Unknown Source)
> at ShareBSM.doit1(ShareBSM.java:12)
> at ShareBSM.main(ShareBSM.java:3)
> java.lang.Exception: Stack trace
> at java.base/java.lang.Thread.dumpStack(Thread.java:1380)
> at ShareBSM.func(ShareBSM.java:8)
> at ShareBSM$$Lambda$2/0x0000000800c00bf8.run(Unknown Source)
> at ShareBSM.doit2(ShareBSM.java:15)
> at ShareBSM.main(ShareBSM.java:4)
> ```
>
> Will you patch generate the same name for both callsites? Does this matter
> for your use case?
@iklam Yes, I tested it against method references too. The patch produces the
same names as it should. I enhanced the test with one additional method that
will explicitly use method references. We don't want confusion about this in
the future.
-------------
PR: https://git.openjdk.org/jdk/pull/10024
