85c38454c0
Move `mir::Field` → `abi::FieldIdx` The first PR for https://github.com/rust-lang/compiler-team/issues/606 This is just the move-and-rename, because it's plenty big already. Future PRs will start using `FieldIdx` more broadly, and concomitantly removing `FieldIdx::new`s.
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.