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WebAssembly Core Dumps and Debugging

1 post · Aug 2023

What this trail covers

Cloudflare Workers is exploring and implementing advanced debugging capabilities for WebAssembly (Wasm) within its runtime. This includes investigating the potential for Wasm core dumps, a critical feature for post-mortem debugging of application crashes. While the core Wasm specification for core dumps is still experimental and not yet fully supported in the Cloudflare Workers runtime (workerd), the company is actively researching and developing polyfilling techniques using tools like wasm-coredump-rewriter to enable debugging of Rust and Wasm code in Workers.

All Cloudflare trails
  1. Wasm core dumps and debugging Rust in Cloudflare WorkersThis post introduces the concept of WebAssembly core dumps, explains their generation and structure using DWARF, and discusses the current experimental status of core dump support in Wasm runtimes. It highlights that Cloudflare Workers' runtime (workerd) does not yet natively support Wasm core dumps due to their experimental nature. To address this, the post introduces and explains the functionality of `wasm-coredump-rewriter`, a polyfilling tool that rewrites Wasm modules to inject core dump runtime functionality, enabling post-mortem debugging of Rust and Wasm code in Cloudflare Workers.