compiler: remove AbiAlign inside TargetDataLayout AbiAlign is a thin wrapper around Align, extant mostly because we used to track a separate quasi-notion of alignment that was never a real notion of alignment and removing all of it at once was too churny. This PR maintains AbiAlign usage in public API and most of the compiler, but direct access of these fields for TargetDataLayout is now in terms of Align only.
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.