This reverts commit 557359f92512ca88b62a602ebda291f17a953002, reversing changes made to 1e6c09a803fd543a98bfbe1624d697a55300a786.
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.