Now I am become the Destroyer of Threads

Roberto Vidal, a Core Tech Engineer, discusses the challenges and solutions associated with implementing multithreading in WebAssembly, particularly when using Rust and wasm-bindgen. While multithreading is a significant advancement for WebAssembly, allowing for the creation of a Node runtime on the Web, it comes with limitations, such as the lack of support for certain thread-based abstractions and automatic memory deallocation. To address a specific memory leak issue related to thread destruction, Vidal and his team proposed a manual solution involving a helper function, __wbindgen_thread_destroy(), to manage memory deallocation. This approach required intricate changes to the memory initialization process and the introduction of a temporary stack to avoid conflicts during memory allocation and freeing. Despite the complexities and the need for manual intervention, the solution was successfully integrated into wasm-bindgen, contributing to the evolving landscape of multithreaded WebAssembly, which continues to develop with initiatives like wasi-threads.