Port wasm2c to binaryen

[lexi-nadia]

As discussed in #2348 (and mentioned in my comment), I'm currently exploring porting wasm2c to binaryen. The comment didn't attract much attention, so I'm posting this as a top-level bug to make sure that interested - or concerned :) - parties see it.

Please let me know if you have any questions, concerns, or feedback!

[keithw]

You are welcome to explore that! I also have a team this summer that will explore porting wasm2c to run on wasmparser (part of wasm-tools), which I am excited about, but probably we should both go ahead and see which one seems more maintainable after we have some experience.

[lexi-nadia]

I mean, from my perspective, I'm much more excited about the future of a Rust-based tool than a C++ one! So I'm really excited for your project too, and I hope it succeeds. :)

[sbc100]

The advantage of porting to binaryen of course is that we wouldn't need the source language would stay they same.. so it should be more straight forward I would hope.

[keithw]

@lexi-nadia If you want to be part of our effort, we'd be happy to loop you in -- we're likely to start in a few weeks.

Part of my thinking on liking wasmparser is that assembling an IR for the whole module (as WABT does and I think binaryen also does) is getting pretty slow when transpiling gigantic modules, so it would be really nice to do this in a streaming way. But this would be a bigger change in how we do it.