329a73dbd6
Refactor the WriteBackendMethods and ExtraBackendMethods traits The new interface is slightly less confusing and is easier to implement for non-LLVM backends.
The codegen crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc dev guide.