HOWTO: WebAssembly Source Maps to C/C++ with Firefox
How to set breakpoints and step through your original source files throughout the runtime execution of your WASM binary.
Using Firefox Quantum Beta Developer Edition on Windows 10. (Doesn't work in Chome AFAICT at time of writing)
Compiled with Visual Studio 2017 Community Edition, Emscripten 1.37.0, SDL2.0.6, and ANGLE-bf90b60.