(WIP) LLVM Codegen

When Rust calls an LLVM DIBuilder function, LLVM translates the given information to a “debug record” that is format-agnostic. These records can be inspected in the LLVM-IR.

It is important to note that tags within the debug records are always stored as DWARF tags. If the target calls for PDB debug info, during codegen the debug records will then be passed through a module that translates the DWARF tags to their CodeView counterparts.