[PATCH] D69807: [WebAssembly] Track frame/stack pointer local for debug information

[Derek Schuff via Phabricator via llvm-commits]

dschuff added a comment.

I think the general idea here makes sense, although as-is I'm afraid it might be brittle. I think for this to work, we'd need to ensure that the frame base stays in the designated local for the whole function, correct? i.e. we'd have to ensure it never gets stackified, which it currently could, right?

Come to think of it, do we know that the CFA is always correct in that case ? IIUC if SP gets stackified, we'd need to emit CFA definition instructions to ensure that the debugger could follow it from the local to the stack, possibly to another local, etc. I think that could work (e.g. we could use `DW_CFA_def_cfa_expression`) but I don't know that it would work out of the box. How are you handling this with wasmtime right now?


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