C ASR Helpers

Various C/C++ helpers for interacting with LiveSplit's Auto Splitting Runtime.

This repo expects you're using Clang to compile. I've listed the extensions which are used, if you want to try port it to another compiler. One thing used a lot in general is the assumption that char strings can be transparently cast to utf8 uint8_t ones - strictly speaking this isn't guaranteed.

To get a wasm-capable Clang install, the easiest way I've found is:

1. Install Clang normally
2. Check if it included a file <LLVM>/lib/clang/[version]/lib/wasi/libclang_rt.builtins-wasm32.a
3. If not, download libclang_rt.builtins-wasm32-wasi-[version].tar.gz, and extract it to that location
4. Download wasi-sysroot-[version].tar.gz, and whenever compiling specify it as the sysroot.

To build the hello world project, using the provided CMake files.

1. Make sure you also have CMake and a Ninja installed
2. Copy/symlink the wasi sysroot to wasi-sysroot in the repo root dir.

3. cmake . --preset debug
   cmake --build build
   

Targets

asr

C headers holding the ASR interface - all exported functions and their types.

Note that the actual ASR interface uses a few "non-zero" types - we can't make this guarantee in C (Clang's nullable extensions only apply to pointers, not integer types). This means you won't get warned about passing zeros in. The runtime will error gracefully though, there's no undefined behaviour.

asr_asl

Provides asl-like callbacks for asr scripts. See it's readme for more.

Requires the extension __attribute__((export_name)) to specify exported wasm symbols.

Requires the extension __attribute__((weak)) so that it can provide default empty implementations, which are overwritten by those you write in your own scripts. You can define ASL_NO_WEAK_DEFAULTS to avoid this, though you'll have to implement every function yourself then.

asr_utils

A more heavyweight C++ library, containing various more advanced helpers. Again see it's readme for more.

Requires C++20, and specifically within it std::format. Shouldn't rely on any implementation defined behaviour though, just need to make sure your library is new enough.

hello_world

A basic hello world script, using only the asr library.

Requires the extension __attribute__((export_name)) to specify exported wasm symbols.