Extending a meta-tracing compiler to mix method and tracing compilation

Meta-interpreter-based just-in-time compiler frameworks provide a convenient way for language designers to implement efficient virtual machines. Those frameworks either employ tracing-based or method- (or partial evaluation) based strategies, which have their own pros and cons. This paper proposes an approach to enable both tracing- and method-based compilation so that the runtime can selectively apply an appropriate strategy to different parts of a program. The proposal basically extends a meta-tracing compiler to method-based compilation by roll backing at conditional branches, trace-splitting at loop entries, and not following at function calls. As a proof-of-concept, we implemented a tiny meta-tracing compiler in MinCaml by following the RPython's architecture and extended it to support both tracing- and method-based compilation.