It's been about a month since I started refactoring the Higgs JIT to implement a lazy/incremental compilation strategy. The new JIT will combine the basic block versioning scheme I previously implemented with lazy compilation of basic block versions and eventually incremental inlining of function calls. This is a natural extension of basic block versioning which I believe will bring many interesting possibilities, such as the ability to recompile or invalidate code at the level of individual basic blocks.