OCaml WASM runtime

[Marigold-infrabot]

Objective
Deadline: 2022-10-25 00:00:00

[d4hines]

Why

WASMer is fast, but it's complex. This, combined with requiring us to interop with Rust somehow, makes WASMer too expensive for Deku's current complexity budget.

What We'll Do

First step is to migrate back to the reference WASM runtime in OCaml. This will clean up a few things for us:

• no more unix pipes in Deku-C.The parametric in Deku-P can be a plain OCaml functor. WASM support can be in terms of this, as can support for unix pipes.
  • According to @Zett98 and @EduardoRFS, named pipes are not as simple as they appear to my naive eyes.
• single process/binary. Simplifies packaging and deployment
• No more rust.
• No more OCaml4.14 - use OCaml5.0 everywhere

It's not that we're anti-Rust - we may rewrite Deku in Rust next year. But that's next years problem - if we're going to hit this year's benchmarks we've got to constrain our complexity. Rust isn't critical to our strategy, so lets drop it until it becomes such.