wasi-sdk VS linux

I would really love being able to take any POSIX command line tool, compile that to WASI, and run it on (at least) Linux, Windows and macOS like a regular executable without having to install a separate WASI runtime.

I'm a 'WASI convert' since I was able to take an ancient 8-bit assembler written in the mid-90's (http://xi6.com/projects/asmx/), compile that as-is with the WASI SDK (https://github.com/WebAssembly/wasi-sdk), and then integrate it into a VSCode extension (https://marketplace.visualstudio.com/items?itemName=floooh.v...).

A similar problem is I have is a shader cross-compiler (https://github.com/floooh/sokol-tools) which needs to run Linux, macOS and Windows and takes too long to build locally, thus I currently need to distribute that as pre-built binaries. Compiling this to WASI works, but the filesystem access restrictions built into current wasm runtimes are a hassle to manage, and it would require a WASI runtime to be separately installed).

There is the WASI SDK if you want to target WASI from C/C++:

https://github.com/WebAssembly/wasi-sdk

It may not have all the amenities of Emscripten, but it's way less bulky.

The most direct way to debug WebAssembly is through the WebAssembly System Interface (WASI). In itk-wasm, we can build to WASI with the WASI SDK by specifying the itkwasm/wasi toolchain image. A backtrace can quickly be obtained with the itk-wasm CLI. Or, a fully fledged debugger session can be started with LLDB.

We use the add_executable command to build executables with itk-wasm. The Emscripten and WASI toolchains along with itk-wasm build and execution configurations are contained in itk-wasm dockcross Docker images invoked by the itk-wasm command line interface (CLI). Note that the same code can also be built and tested with native operating system toolchains. This is useful for development and debugging.

A more lightweight tool than emscripten is the WASI SDK (https://github.com/WebAssembly/wasi-sdk/releases). However, it doesn't generate JS or HTML.

wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-16/wasi-sdk-16.0-macos.tar.gz

First, we’ll download the wasi-sdk. We’ll use wasi-sdk-16.0-linux.tar.gz, the latest version available when writing this article. We’ll move the file to the /opt directory and unpack it as follows:

I'm intrigued. Pretty good write-up about it here. One would need an ebuild for wasi-libc and an ebuild for wasi-sdk.

The previously mentioned PR for wasm32-unknown-unknown compatibility solved this by including libc .c files from OpenBSD. My go to solution is different though. I prefer to build using the wasi-sdk (a WASI-enabled WebAssembly C/C++ toolchain).

There's also the https://github.com/WebAssembly/wasi-sdk repo which is kind of a meta-build-system for all this.

But in FreeBSD we build all the pieces directly, here's our build recipes (with some hacks due to llvm's cmake code being stupid sometimes):

compiler-rt (from llvm): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...

libc (from what you linked): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...

libc++ (from llvm): https://github.com/freebsd/freebsd-ports/blob/main/devel/was...

> Torvalds answered that, while he used to find problems in the LLVM Clang compiler, now he's more likely to find problems with GCC instead; he now builds with Clang.

https://github.com/ClangBuiltLinux/linux/issues is our bug tracker for known issues (a few are tracked in llvm's issue tracker). Bug reporters and future kernel hackers wanted!

As I mentioned on mastodon, there's lots of bugs still to be fixed everywhere, but even if we don't fix them, providing competition in the toolchain space has been worth it to users.

Linux builds on clang after a decade of dedicated effort to make it happen, and that is with clang overall being comparatively similar to gcc (e.g clang implements many gcc extensions): https://github.com/ClangBuiltLinux/linux/wiki/Project-histor...

We got plenty of bugs for building the kernel with LLVM, if you're looking for tasks, pick one!

There's an semi-official github[0] for this.

AFAICT from the issue, Clang and binutils/LLVM tools work fine with no patches for the mainstream archs and when not trying to be super-fancy with custom flags. The more non-mainstream one goes with arch or flags the more likely one will run into something.

[0] https://github.com/ClangBuiltLinux/linux/issues

If you have any reproducible issues please file them here: https://github.com/ClangBuiltLinux/linux/issues

See if you can build your distro's config. make LLVM=1 localmodconfig olddefconfig bzImage. Any warnings? Any warnings not in the issue tracker? If not, pick one from the issue tracker and see if you can reproduce it. Note: lots of issues are tagged by target ISA, so you'll need to get familiar with cross compiling (setting ARCH= and CROSS_COMPILE=.

It's a pipeline; clang starts, hands off to LLVM.

For a compilation to object file from source code, the vast majority of time for most translation units is spent in the front end of the pipeline, not the middle, or backend.

See also my first plot: https://github.com/ClangBuiltLinux/linux/issues/1086#issueco...