Formally Verified Native Code Generation in an Effectful JIT: Turning the CompCert Backend into a Formally Verified JIT Compiler

Modern Just-in-Time compilers (or JITs) typically interleave several mechanisms to execute a program. For faster startup times and observe the initial behavior of an execution, interpretation can be initially used. But after while, JITs dynamically produce native code for parts program they often. Although some time is spent compiling dynamically, this mechanism makes much remaining execution. Such are complex pieces software with various components, greatly rely on precise interplay between different languages being executed, including on-stack-replacement. Traditional static like CompCert have been mechanized in proof assistants, but scarcely formalized so far, partly due their impure nature numerous components. This work presents model JIT dynamic generation code, implemented formally verified Coq. cannot written Coq, we propose methodology delimit, specify reason effects JIT. We argue that daunting task verifying complete should draw existing proofs generation. To end, our successfully reuses its correctness during compilation. Finally, prototype extracted executed.