[mraleph]

At some point in my life (when I briefly worked on LuaJIT for DeepMind) I have written a stack walker which can stitch together native and Lua frames: for each native stack frame it checks if that is actually an interpreter frame or a trace frame - if that's the case it finds corresponding `lua_State` and unwinds corresponding Lua stack, then continues with native stack again.

This way you get a stack trace which contains all Lua and native frames. You can use it when profiling and you can use it to print hybrid stack traces when your binary crashes.

I was considering open-sourcing it, but it requires a bunch of patches in LJ internals so I gave up on that idea.

(There is also some amount of over-engineering involved, e.g. to compute unwinding information for interpreter code I run an abstract interpretation on its implementation and annotate interpreter code range with information on whether it is safe or unsafe to try unwinding at a specific pc inside the interpreter. I could have just done this by hand - but did not want to maintain it between LJ versions)