WebAssembly has begun to establish itself outside of the browser via dedicated runtimes like Mozilla’s Wasmtime and Fastly’s Lucet. While the promise of a new, universal format for programs is appealing, it also comes with new challenges. For instance, how do you debug .wasm binaries?

At Mozilla, we’ve been prototyping ways to enable source-level debugging of .wasm files using traditional tools like GDB and LLDB.

The screencast below shows an example debugging session. Specifically, it demonstrates using Wasmtime and LLDB to inspect a program originally written in Rust, but compiled to WebAssembly.

Read more >