Here is what I want to do:
Even though LLVM is now used today mostly for its optimizations and backend roles in compilation, as its core it is the Low-Level Virtual Machine.
LLVM can JIT code, even though the return types may be quite opaque, so if you are ready to wrap your own code around it and don't worry too much about the casts that are going to take place, it may help you.
However C and C++ are not really friendly for this kind of thing.