[code-reflection] RFR: BytecodeGenerator support of lambdas [v7]

[Chen Liang]

On Tue, 16 Apr 2024 16:50:18 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

>> I've identified `j/l/i/defineHiddenClass/BasicTest::testLambda` is actually not testing a lambda in a hidden class, but rather a MH in a hidden class.
>> If I modify `j/l/i/defineHiddenClass/src/Lambda` from `Function<Object, String> f = Object::toString;` to `Function<Object, String> f = o -> o.toString();` the test fails with:
>> 
>> java.lang.NoClassDefFoundError: Lambda/0x00007ff00029e800
>> 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
>> 	at java.base/java.lang.reflect.Method.invoke(Method.java:641)
>> 	at java.base/java.util.ArrayList.forEach(ArrayList.java:1597)
>> 	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
>> 	at java.base/java.lang.reflect.Method.invoke(Method.java:641)
>> 	at java.base/java.lang.Thread.run(Thread.java:1575)
>> Caused by: java.lang.ClassNotFoundException: Lambda.0x00007ff00029e800
>> 	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
>> 	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
>> 	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525)
>
> That seems like a bug to me, although i can understand why it might not seem like that too :-)

`InnerClassLambdaMetafactory` doesn't seem to support hidden classes for `implClass`, but it can easily support them if we allow for hidden `implClass` to only use invokestatic (maybe getstatic and putstatic too) and route such `implClass` to always use condy.

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PR Review Comment: https://git.openjdk.org/babylon/pull/48#discussion_r1567914761