The rustwasmc tool

Jun 17, 2020 • 2 minutes to read

Throughout our examples, we make extensive use of the rustwasmc tool. It is inspired by the wasm-pack project but is optimized for edge cloud and device applications. Specifically, it supports the WasmEdge WebAssembly runtime.


The rustwasmc depends on the Rust cargo toolchain to compile Rust source code to WebAssembly. You must have Rust installed on your machine.

$ curl --proto '=https' --tlsv1.2 -sSf | sh
$ source $HOME/.cargo/env
$ rustup override set 1.50.0


The easiest way to install rustwasmc is to use its installer.

$ curl -sSf | sh

Alternatively, you can install using the NPM if you'd like.


To build Rust functions for Node.js applications, use the following command. See a template application.

$ rustwasmc build

Use the --enable-ext flag to compile Rust programs that use WASI extensions, such as WasmEdge's storage and tensorflow APIs. The rustwasmc will run the compiled WebAssembly bytecode program in the wasmedge-extensions Node.js module instead of wasmedge-core in this case.

$ rustwasmc build --enable-ext

Support AOT

A key feature of the WasmEdge runtime is its support for Ahead-of-Time (AOT) compilers. When you run WebAssembly programs in Node.js wasmedge-core and wasmedge-extensions add-ons, you typically do not need to worry about it as the add-on handles AOT compilation transparently. However, in some cases, you do want the rustwasmc to compile and generate native code for the program.

Then, use the commands below to bring your operating system up to date with the latest developer tools. The commands here are tested on Ubuntu 20.04.

$ sudo apt-get update
$ sudo apt-get -y upgrade
$ sudo apt install build-essential curl wget git vim libboost-all-dev llvm-dev liblld-10-dev

Now, you can build the .so files for the AOT native target like the following.

$ rustwasmc build --enable-aot

Enjoy coding!

A high-performance, extensible, and hardware optimized WebAssembly Virtual Machine for automotive, cloud, AI, and blockchain applications