wasm2cretonne

Cretonne frontend for WebAssembly. Reads wasm binary modules and translate the functions it contains into Cretonne IL functions.

The translation needs some info about the runtime in order to handle the wasm instructions get_global, set_global, and call_indirect. These informations are included in structs implementing the WasmRuntime trait like DummyRuntime or StandaloneRuntime.

The StandaloneRuntime is a setup for in-memory execution of the module just after translation to Cretonne IL. It allocates memory for the wasm linear memories, the globals and the tables and embeds the addresses of these memories inside the generated Cretonne IL functions. Then it runs Cretonne's compilation, emits the code to memory and executes the start function of the module.

API

Use the functions defined in the crates wasm2cretonne and wasmruntime.

Example

use wasm2cretonne::translate_module;
use wasmruntime::{StandaloneRuntime, compile_module, execute};
use std::path::{Path, PathBuf};

fn read_wasm_file(path: PathBuf) -> Result<Vec<u8>, io::Error> {
    let mut buf: Vec<u8> = Vec::new();
    let file = File::open(path)?;
    let mut buf_reader = BufReader::new(file);
    buf_reader.read_to_end(&mut buf)?;
    Ok(buf)
}

let path = Path::new("filetests/arith.wasm");
let data = match read_wasm_file(path.to_path_buf()) {
    Ok(data) => data,
    Err(err) => {
        panic!("Error: {}", err);
    }
};
let mut runtime = StandaloneRuntime::new();
let translation = match translate_module(&data, &mut runtime) {
    Ok(x) => x,
    Err(string) => {
        panic!(string);
    }
};
let exec = compile_module(&translation, "intel");
execute(exec);
println!("Memory after execution: {:?}", runtime.inspect_memory(0,0,4));

CLI tool

The binary created by the root crate of this repo is an utility to parse, translate, compile and execute wasm binaries using Cretonne. Usage:

wasm2cretonne-util <files to translate>
    -v, --verbose       displays info on the different steps
    -p, --print         displays the module and translated functions
    -c, --check         checks the corectness of the translated functions
    -o, --optimize      runs optimization passes on the translated functions
    -e, --execute       enable the standalone runtime and executes the start function of the module
    -m, --memory        interactive memory inspector after execution

The tool reads .wasm files but also .wast as long as the WebAssembly binary toolkit's wast2wasm executable is accessible in your PATH. For now, only the 64 bits Intel architecture is supported for execution.