"libcpu" is an open source library that emulates several CPU architectures, allowing itself to be used as the CPU core for different kinds of emulator projects. It uses its own frontends for the different CPU types, and uses LLVM for the backend. libcpu is supposed to be able to do user mode and system emulation, and dynamic as well as static recompilation.
These details are provided for information only. No information here is legal advice and should not be used as such.