AOT caching of WeakReference

[Erik Osterlund]

Hi Ioi,

You can also get caught with a WR with discovered fields and next fields populated. They are mutated by the GC. They can drag in random unrelated stuff into your object graph that you might not want to stuff into the archive.

/Erik

> On 14 Nov 2024, at 22:48, ioi.lam at oracle.com wrote:
> 
> Here's my  experiment with storing weak references in the AOT cache
> 
> https://github.com/iklam/jdk/blob/8341587-example-of-weakref-problem-in-aot-cache/AOT-Cache-And-WeakRef.md
> 
> As discussed in the Leyden meeting today, there seem to be at least two issues
> 
> - In premain, CDS keeps every archived heap object alive (look for UsePermanentHeapObjects in the code). I plan to get rid of this shortly. UsePermanentHeapObjects is intended for the AOT compiler to access heap objects, but it should be implemented differently (only remember objects that are required by AOT code, which should include only Strings and class mirrors).
> 
> - WeakReference.queue is not pointing to the production-time value of ReferenceQueue.NULL
> 
> 
> Thanks
> 
> - Ioi
>