swift234

IRGen: Get "hello world" to compile through SIL.
Add a path through IRGenModule to optionally codegen FuncDecls using their corresponding SIL Functions when constructed with a SILModule. Jury-rig an IRGenSILFunction subclass of IRGenFunction that does the bare minimum necessary to compile "hello world" from SIL. There are some impedance mismatches between irgen and SIL that need to be smoothed out, particularly the AST-dependent way irgen currently handles function calls. Nonetheless, `swift -sil-i hello.swift` works!

Swift SVN r3759