Request: Wasi support

[rjzak]

In your blog post, you discuss the use of WebAssembly and Javascript for use in the browser. How about support for Wasi and a runtime environment like Wasmtime? It might even just work out of the box, I haven't yet tried your Docker image.

[StarGate01]

Hi, thanks for bringing this up, interesting idea.

At the moment, the toolchain uses the gfortran runtime provided by GCC, which relies on libc. Emscripten then provides the needed libc/musl binding to the existing Browser system interfaces.

Implementing support for a completely new system backend would require either replacing libc with something call-compatible that uses Wasi in the background, or moving to a different compiler infrastructure. I am still hoping for LLVM/flang to be released, moving to a 100% LLVM toolchain would eliminate many quirks and problems of the current toolchain. However, the flang compiler is not finished yet. In addition, I am unsure how easy it would be to use Wasi as a system backend in LLVM.

If you have any ideas, let me know.

Edit: I had a quick look at Wasi, and it appears that it provides a sizeable set of libc-like APIs. It might be feasible to compile libgfortran using this.

[rjzak]

I think Emscripten can work with Wasi. There are a few examples and there's also the wasi-sdk, which supports C/C++.

I've also been communicating with someone who's been trying to get WebAssembly support added to LFortran here. There was an additional PR 6 months ago, but it wasn't approved.

[StarGate01]

LFortran is a really cool project, but not yet complete enough to run most/all of the scientific codes I usually work with. See https://docs.lfortran.org/progress/ . I had a look at it in 2020 when I started this project, and it seems like a lot has been implemented since. But there are still more functions needed for full support.

I am intrigued by the Wasi framework. I'll take a more thorough look at it in the next days. This might help me with a semi-related project.