Refactor filename/directory in DICompileUnit into a DIFile

This is the next step towards making the metadata for DIScopes have a common
prefix rather than having to delegate based on their tag type.

llvm-svn: 176913
diff --git a/llvm/test/CodeGen/X86/dwarf-comp-dir.ll b/llvm/test/CodeGen/X86/dwarf-comp-dir.ll
index 63e6167..17e7eea 100644
--- a/llvm/test/CodeGen/X86/dwarf-comp-dir.ll
+++ b/llvm/test/CodeGen/X86/dwarf-comp-dir.ll
@@ -6,9 +6,10 @@
 
 !llvm.dbg.cu = !{!0}
 
-!0 = metadata !{i32 720913, i32 0, i32 12, metadata !"empty.c", metadata !"/home/nlewycky", metadata !"clang version 3.1 (trunk 143523)", i1 true, i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !1, metadata !1} ; [ DW_TAG_compile_unit ]
+!0 = metadata !{i32 720913, i32 0, i32 12, metadata !3, metadata !"clang version 3.1 (trunk 143523)", i1 true, i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !1, metadata !1} ; [ DW_TAG_compile_unit ]
 !1 = metadata !{metadata !2}
 !2 = metadata !{i32 0}
+!3 = metadata !{i32 786473, metadata !"empty.c", metadata !"/home/nlewycky", null} ; [ DW_TAG_file_type ]
 
 ; The important part of the following check is that dir = #0.
 ;                        Dir  Mod Time   File Len   File Name