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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176913 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/ARM/2010-08-04-StackVariable.ll b/test/CodeGen/ARM/2010-08-04-StackVariable.ll
index 5fd31f4..6bfc957 100644
--- a/test/CodeGen/ARM/2010-08-04-StackVariable.ll
+++ b/test/CodeGen/ARM/2010-08-04-StackVariable.ll
@@ -79,7 +79,7 @@
 !0 = metadata !{i32 786478, i32 0, metadata !1, metadata !"SVal", metadata !"SVal", metadata !"", metadata !2, i32 11, metadata !14, i1 false, i1 false, i32 0, i32 0, null, i1 false, i1 false, null} ; [ DW_TAG_subprogram ]
 !1 = metadata !{i32 786451, metadata !2, metadata !"SVal", metadata !2, i32 1, i64 128, i64 64, i64 0, i32 0, null, metadata !4, i32 0, null} ; [ DW_TAG_structure_type ]
 !2 = metadata !{i32 786473, metadata !"small.cc", metadata !"/Users/manav/R8248330", metadata !3} ; [ DW_TAG_file_type ]
-!3 = metadata !{i32 786449, i32 0, i32 4, metadata !"small.cc", metadata !"/Users/manav/R8248330", metadata !"4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", i1 false, metadata !"", i32 0, metadata !47, metadata !47, metadata !46, metadata !47, metadata !""} ; [ DW_TAG_compile_unit ]
+!3 = metadata !{i32 786449, i32 0, i32 4, metadata !2, metadata !"4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", i1 false, metadata !"", i32 0, metadata !47, metadata !47, metadata !46, metadata !47, metadata !""} ; [ DW_TAG_compile_unit ]
 !4 = metadata !{metadata !5, metadata !7, metadata !0, metadata !9}
 !5 = metadata !{i32 786445, metadata !1, metadata !"Data", metadata !2, i32 7, i64 64, i64 64, i64 0, i32 0, metadata !6} ; [ DW_TAG_member ]
 !6 = metadata !{i32 786447, metadata !2, metadata !"", metadata !2, i32 0, i64 64, i64 64, i64 0, i32 0, null} ; [ DW_TAG_pointer_type ]