A JVM in Rust part 5 – Executing instructions

Re:A JVM in Rust part 5 – Executing instructions by bialpio on Monday August 28, 2023 @05:33PM (#37300673)

IIUC this should be fine - MemoryChunk doesn't seem to deallocate the memory (so we leak), unless there's a dealloc somewhere (sorry, not logged in to GH so cannot search). Which is not the worst outcome here, because as you said, we don't want to deallocate this memory since there may be places that still refer to it...

As for where the static lifetime gets into play, VM creation doesn't use unsafe & compiler is happy about it, even though ISTM that there could be a tighter bound on the lifetime? https://github.com/andreabergia/rjvm/blob/93e7e48db085e780b0...

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Re:A JVM in Rust part 5 – Executing instructions by skitter on Monday August 28, 2023 @05:53PM (#37300878)

VM creation is using unsafe (the line I pointed out above). You're right, I can't find any deallocation either – but weirdly it /does/ segfault (or sometimes have other memory related errors) if I drop the VM while it's heap is still referenced.

The thing with a tighter bound on the lifetime is that VM carrying a lifetime for itself is fundamentally flawed. A solution would be to remove said lifetime, and have all methods on VM that return lifetimed objects take said lifetime from the reference to the VM.

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Re:A JVM in Rust part 5 – Executing instructions by andreabergia on Tuesday August 29, 2023 @02:06AM (#37304017)

That sounds reasonable (and way better than what I have implemented).

I am not sure I am going to try it though - it probably is a bit too much code to change for something that I consider "done" and I am not working on. :)

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