Writing wasm tooling in Rust

[aturon]

This issue tracks existing and potential wasm tooling opportunities for Rust.

One of the exciting things about the wasm space is that there's a lot of need for brand new systems code to be written in the tooling space, e.g. code to munge .wasm files. A lot of the early tooling has been written in C++, but there's a real opportunity for Rust to serve as a common language both for writing wasm tools and for producing wasm code.

Existing wasm tools written in Rust

• wasm-gc, "a small command to gc a wasm module and remove all unneeded exports, imports, functions, etc."
• wasm-nm, "list the symbols within a wasm file".
• wasm-snip, "replaces a wasm function body with unreachable"
• rustwasm, a wasm interpreter in Rust
• wasmi, wasm interpreter in Rust,
• parity-wasm, wasm (de)serialization in Rust,
• wasmparser - a wasm binary decoder with optional validation, in Rust
• wasmtext - prints wasm modules in text format, in Rust
• wasmstandalone - standalone JIT-based wasm runner, in Rust, using Cretonne, in early development

Desired wasm tools that could be written in Rust

• wasm size profiler

Possible RIIR opportunities

Here are some existing tools that could, in principle, be (re)written in Rust instead:

• The wabt tools
• Tools for the ewasm project

[aturon]

A good example here is @alexcrichton's wasm-gc.

What are some other existing Rust-based tools we know about? And what are some needed tools we could start writing Rust code for?

[fitzgen]

https://github.com/fitzgen/wasm-nm https://github.com/fitzgen/wasm-snip

[aturon]

• A wasm interpreter in Rust
• wasm serialization in Rust

[aturon]

Added some RIIR (rather than WIIR) opportunities to the issue. This is more to inspire ideas for additional tools, rather than to suggest RIIR today.

[sunfishcode]

More existing projects:

• wasmparser - a wasm binary decoder with optional validation, in Rust
• wasmtext - prints wasm modules in text format, in Rust
• wasmstandalone - standalone JIT-based wasm runner, in Rust, using Cretonne, in early development

[pepyakin]

btw parity-wasm also contains an interpreter.

[pepyakin]

ah i see, WIIR - write it in rust

[aturon]

@pepyakin thanks, clarified both.

[pepyakin]

Recently I spent a looot of time in wast code generated by Rust+emcc+fastcomp/Rust+emcc+llvm and recently with unknown-unknown. I think it would be cool if I have had something like a decompiler for WASM.

I don't know much about decompilers but I tend to think it should be easier to write one for wasm comparing to some "real" isa.

[alexcrichton]

From my experience parity-wasm has solved all problems for parsing/encoding a wasm module, but I think it'd also be slick to have a crate 100% dedicated to just that (in that parity-wasm also has an interpreter).

[mgattozzi]

Looks like somebody is working on wabt bindings in rust as well:
https://github.com/pepyakin/wabt-rs

[pepyakin]

@alexcrichton there was some discussions about splitting interpreter into a separate crate. I actually like the idea.

[pepyakin]

Yep, actual split of interpreter took place: https://github.com/pepyakin/wasmi
It has quite a few differences from parity-wasm version.

[spastorino]

I'm interested in helping here, will ping sbdy on IRC :).

[frehberg]

hi, I used Rust to implement the https://github.com/frehberg/wasm-sign

[alexcrichton]

We've made a lot of progress here and I think we've reached a good steady state, so closing.