RFR: 8341587: [premain] Support Soft/Weak Reference in AOT cache [v3]

[Ioi Lam]

On Wed, 19 Feb 2025 16:54:47 GMT, Mat Carter <macarte at openjdk.org> wrote:

>> src/java.base/share/classes/java/lang/invoke/MethodTypeForm.java line 134:
>> 
>>> 132:     @SuppressWarnings({"rawtypes", "unchecked"})
>>> 133:     public LambdaForm cachedLambdaForm(int which) {
>>> 134:         Object entry = lambdaForms[which];
>> 
>> I recommend restoring the static types of the arrays to `SoftReference<MethodHandle>[]` unless there is extra overhead from loading/initialization of `SoftReference` class.
>
> I tried this before but then 'this.methodHandles = new SoftReference<MethodHandle>[MH_LIMIT];' is not allowed due to the error 'generic array creation'.  I looked at allocating using ArrayList<>(initialCapacity) as they are backed. with Object[], but then we have to add range checks on the reads to avoid IndexOutOfBounds or set a null entry at (initialCapacity-1); unless someone can suggest a better implementation I'm inclined to let it stand

@macarte I think you can try restoring all these touched by JEP 483 to the prior version. I can see that there are a few changes in MethodTypeForm.java that you haven't restored yet

https://github.com/openjdk/jdk/commit/41a2d49f0a1ed298b8ab023ce634335464454fe7#diff-26f13a6a296ac624577fb32626de70ed7c56b1a1c80fde258aea71a25b7560e2

- LamdaFormEditor.java
- MethoHandleNatives.java
- MethodType.java
- MethodTypeForm.java

That should get rid of the compilation error you mentioned above.

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PR Review Comment: https://git.openjdk.org/leyden/pull/41#discussion_r1962332413