Rustc_codegen_cranelift (cg_clif) is an alternative backend for rustc that I have been working on for the past two years. It uses the Cranelift code generator. Unlike LLVM which is optimized for output quality at the cost of compilation speed even when optimizations are disabled, Cranelift is optimized for compilation speed while producing executables that are almost as fast as LLVM with optimizations disabled. This has the potential to reduce the compilation times of rustc in debug mode.
I recently looked back at the notes for the design meeting (meeting proposal) about integrating cg_clif into rustc. I noticed that several of the challenges that needed to be solved have since been solved. Because of this I decided to give an overview of the achievements in the past six months and what the current challenges are.