globals – make their performance less awful · Issue #8870 · JuliaLang/julia (original) (raw)
This keeps coming up, and rather than direct people to the performance tips, I feel like we should really just try to fix the issue. One relatively non-disruptive approach might be to emit code that accesses globals with a fast path that assumes that they have the same type that they currently have and a slow path that handles arbitrary type. A harder fix would be the compile-time version of that: generate code that assumes that globals retain their current type and invalidate it if the type changes. One might want to let compilation happen a couple of times before giving up and generating pessimistic general code.