b20e3ff2af
Refactor linker code This merges `LinkerInfo` into `CrateInfo` as there is no reason to keep them separate. `LinkerInfo::to_linker` is merged into `get_linker` as both have different logic for each linker type and `to_linker` is directly called after `get_linker`. Also contains a couple of small cleanups. See the individual commits for all changes.
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.