RFR: 8377512: AOT cache creation fails with invalid native pointer

[John R Rose]

On Thu, 19 Feb 2026 17:20:07 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> Since JDK 25, we have two bugs that cause a pointer to an excluded class to be referenced by a cached heap object.
> 
> [1] Method references to excluded classes: 
> 
> 
> interface A {
>     Object get();
> }
> ...
> A a = ShouldBeExcluded::new; // line 1
> 
> 
> [2] Invocation of a `MethodHandle` whose `MethodType` includes an excluded class:
> 
> 
> MethodHandle constructorHandle =
>     MethodHandles.lookup().unreflectConstructor(ShouldBeExcluded.class.getConstructor());
> // The JVM rewrites the following invoke() from
> // invokevirtual <java/lang/invoke/MethodHandle.invoke()LShouldBeExcluded;>
> // to
> // invokehandle <java/lang/invoke/MethodHandle.invoke()LShouldBeExcluded;>
> ShouldBeExcluded o = (ShouldBeExcluded)constructorHandle.invoke(); // line 2
> 
> 
> In the above examples, during the training run, the AOT configuration file records the fact that the constant pool entries used by line 1 and line 2 have been resolved. Normally, these references are resolved by AOTConstantPoolResolver during the assembly phase (to improve start-up time).
> 
> However, resolving these 2 entries would cause an invalid `MethodType` that references the `ShouldBeExcluded` class to be add into `MethodType::internTable`. Once this happens, it's very difficult for to recover from.
> 
> Therefore, this PR tries to avoid adding such invalid `MethodType` by avoiding the resolution of such constant pool entries.
> 
> Thanks to folks at Azul from coming up with the reproducer.

What Chen said.  Otherwise, good work.

Kind of surprising that we trusted that method-ref class for so long.

Thanks Azul!

-------------

Marked as reviewed by jrose (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29825#pullrequestreview-3857754698