> The goal is to enable JIT codegen without sacrificing too much performance and adding too much maintenance burden, and a functional JIT implementation needs

> The goal is to enable JIT codegen without sacrificing too much performance and adding too much maintenance burden, and a functional JIT implementation needs a few more components other than that---most notably a facility to monitor and trace function calls for the eventual JIT compilation. Consider the OP to be one of intermediate goals, not the eventual goal. It seems like the copy and patch approach is sort of somewhere inbetween an interpreter and a traditional JIT, and the authors of the original copy and patch paper seem to be trying to use it to replace things like the baseline compiler in the two-tier baseline/optimizing compiler strategy used for things like webassembly. Because of this, is it really necessary to add tracing and try use a two tier interpeter/copy-and-patch JIT approach for this python JIT? Wouldn't it make more sense to try to get it to be fast enough that the JIT can be used alone?