Trufflereloader: a low-overhead language-neutral reloader

Updating running programs is a well-researched and increasingly popular feature of programming language implementations. While there are solutions targeting specific languages and platforms, implementing dynamic update for new languages can require significant effort. We have built TruffleReloader, a reusable dynamic updating solution, on top of the Truffle language implementation framework, and adapted the Truffle implementations of Python, Ruby and JavaScript to use this feature. We show how TruffleReloader adds reloading capabilities to these implementations requiring limited language-specific modifications. With Truffle's just-in-time compiler enabled, our solution incurs close to zero overhead on steady-state performance. This approach reduces the effort required to add dynamic update support for existing and future languages.