WASM Micro Runtime (WAMR) over ESP32

This is an attempt to run WASM (Web Assembly) over ESP32 using the wasm-micro-runtime project.

This is an extraction of the sample project already available along with WAMR. Further to that we test support for Rust compiled wasm binary as well.

This is built only for learning purposes, and is not intended for production. We will stick to a simple "Hello world!" for now.

Status

• WASM built using clang
• WASM built using rustc

Instructions

Hardware

You would need a development board. I used an ESP32 development board. Something like this. Theoretically any ESP32 board will suffice.

Also you would need mac / Linux / Windows computer as well for cross compilation and tooling. For my purposes I am using a Raspberry Pi 3B.

Software setup

• Setup esp-idf toolchain using the instructions here. Make sure that you add IDF_PATH to your user profile as mentioned here.
• Clone wasm-micro-runtime from here. Set WAMR_PATH to this path in your user profile.
• Install wasi-sdk as mentioned here.
  • Its okay to use release downloads but it didn't work for me on Linux. I had to compile it.
  • Set WASI_SDK_PATH in your profile correctly to the folder where the artifacts are untar'ed.

Usage

Step 1: Init

Remember to bring esp-idf into path,

$ export $IDF_PATH/export.sh

Clone this repo,

$ git clone git@github.com:anoopelias/hello-wasm-esp32.git
$ cd hello-wasm-esp32

Step 2.a: Build wasm binary using clang

$ cd hello-wasm
$ ./build.sh; cd ..

Step 2.b: Build wasm binary using Rust instead

$ cd hello-wasm-rs
$ ./build.sh; cd ..

Step 3: Build IDF image and flash it

$ ./build_and_run.sh

Step 4: Check logs

$ idf.py monitor

You should be able to see relevant "Hello World" printed in terminal.

...
...
I (0) cpu_start: Starting scheduler on APP CPU.
I (0) wamr: Initialize WASM runtime
I (10) wamr: Run wamr with interpreter
I (10) wamr: Instantiate WASM runtime
I (10) wamr: run main() of the application
Hello clang world!
I (20) wamr: Deinstantiate WASM runtime
I (30) wamr: Unload WASM module
I (30) wamr: Destroy WASM runtime
I (418) wamr: Exiting...