QuaC: Binary Optimization for Fast Runtime Code Generation in C

) Curtis Yarvin Adam Sah Abstract Runtime code generation (RTCG) has considerable theoretical potential but has so far seen little use in practice. Adequate tools are lacking. We present QuaC, an RTCG system that lets C programmers specialize their functions at runtime with a simple, portable user interface. QuaC works by applying compiler optimization techniques to machine code in memory. It is fast and highly retargetable. 1 Introduction In theory, runtime code generation is an extremely powerful technique. Code runs faster when specialized to the current data; and often at runtime data stays constant long enough to be worth the investment of specialized code. Routines specialized to runtime constants will be smaller and faster. This is not a new idea, and in the past many systems have explored the field. Before compilers or an emphasis on portability became widespread, most software was written in assembly language, and programmers found it natural and common to use self-modifyi..