We've discussed engine support for stack walking for application-level GC within linear memory, but there hasn't been a clear win (at least in my mind) over jus

We've discussed engine support for stack walking for application-level GC within linear memory, but there hasn't been a clear win (at least in my mind) over just using a shadow stack, which doesn't require walking frames, just scanning a memory segment. Opening up the contents of executing stack frames imposes a ton of constraints on the engine and complexity (e.g. engine now has to maintain mappings, support frame modification, etc), that have implications for basically all execution tiers. It doesn't seem like the right tradeoff to me. I've implemented a shadow stack for Virgil, so I am aware of how much it sucks. But that doesn't suck as bad as coming up with a stack walking protocol and then modifying every Wasm engine in existence to support that.