Yes, such approaches can be compliant. There's even a few C interpreters. Very popular back in the day for debugging C programs when you didn't have full OS d

Yes, such approaches can be compliant. There's even a few C interpreters. Very popular back in the day for debugging C programs when you didn't have full OS debugging support for breakpoints and etc. Such an approach would be quite suitable for encapsulating untrusted code. There is definitely some major overhead, but I don't see why you couldn't use JIT.