Is `wasm32_wasip1_threads` Rust target supported?

[atilag]

Hey team!
I wanted to use a .wasm module that has been compiled from Rust, using the wasm32_wasip1_threads target but it looks like this target required some imports from the host that are not being satisfied when I try to instantiate a module like:

        engine = Engine()
        
        wasi_config = WasiConfig()
        wasi_config.inherit_stdout()

        store = Store(engine)
        store.set_wasi(wasi_config)

        with open( 'my_wasi_library.wasm', 'rb') as f:
            wasi_bytes = f.read()

        module = Module(engine, wasi_bytes)

        linker = Linker(engine)
        linker.define_wasi()

        instance = linker.instantiate(store, module) # This throws: wasmtime._error.WasmtimeError: unknown import: `env::memory` has not been defined

I would have expected the define_wasi() to prepare everything so the required imports are satisfied, but I guess this wasm32_wasip1_threads target might not be supported just yet?

Thank you very much!!

Awesome work, btw :)

[atilag]

Ok, I see. There's no support for shared memory just yet, right?

[alexcrichton]

IIRC the C API has all the bits necessary for this, but yeah I don't think shared memory is bound yet. This library is notably not threadsafe yet though so you'll need to be careful to use things correctly lest you run into data races.

[atilag]

Yeah, I saw it!
I started to implement the bindings and added a ShareMemory class. So far it's not working due to a crash in the wasmtime runtime part while cloning the shared memory structure, but I have everything setup locally to apply patches there as well, so once I have something more or less working I'll PR.
Thanks Alex!

[atilag]

So, basically, I started implementing SharedMemory until I got here:
https://github.com/bytecodealliance/wasmtime/blob/a5412caa6c7845cfd068d5ed20006711762b660c/crates/c-api/src/extern.rs#L23
I'm not familiar at all with the codebase so after a few hours trying to implement this, I'm not feeling comfortable with my changes... I'll give a stab one more time, and see if I make progress but looks like the implementation of SharedMemory is far from trivial at this point.

[alexcrichton]

Oh I'd recommend instead using wasmtime_* functions from this header if that works?

[thewtex]

Hi @atilag @alexcrichton ,

Thank you so much for your work on this!

Is this issue addressed with #255 merged and released?

[alexcrichton]

I think it should be good yeah, but I think it'd be best to test in a higher-level use case as well before closing perhaps

[thewtex]

@alexcrichton @atilag I am looking to exercise with C++ wasi-sdk modules.

It seems that we need something like a wasmtime_linker_define_wasi_threads similar to wasmtime_linker_define_wasi that calls the wasi-threads add_to_linker and expose it here.

[thewtex]

@alexcrichton @atilag I created a test, initial implementation in bytecodealliance/wasmtime#10030 #265 but I need help with the Rust implementation of wasmtime_linker_define_wasi_threads.

[thewtex]

Per discussion in bytecodealliance/wasmtime#10030 this should probably be closed.

[alexcrichton]

Agreed yeah. It's certainly ok to expose the primitives necessary for shared bits (which I think is done now) but for wasi-threads we're going to hold off on it.