Revert "Revert "PR14606: debug info imported_module support""

This reverts commit r179840 with a fix to test/DebugInfo/two-cus-from-same-file.ll

I'm not sure why that test only failed on ARM & MIPS and not X86 Linux, even
though the debug info was clearly invalid on all of them, but this ought to fix
it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179996 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/DebugInfo/two-cus-from-same-file.ll b/test/DebugInfo/two-cus-from-same-file.ll
index 784df8d..22cf4eb 100644
--- a/test/DebugInfo/two-cus-from-same-file.ll
+++ b/test/DebugInfo/two-cus-from-same-file.ll
@@ -34,14 +34,14 @@
 
 !llvm.dbg.cu = !{!0, !9}
 
-!0 = metadata !{i32 786449, metadata !32, i32 12, metadata !"clang version 3.2 (trunk 156513)", i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !3, metadata !1, metadata !""} ; [ DW_TAG_compile_unit ]
+!0 = metadata !{i32 786449, metadata !32, i32 12, metadata !"clang version 3.2 (trunk 156513)", i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !3, metadata !1, metadata !1, metadata !""} ; [ DW_TAG_compile_unit ]
 !1 = metadata !{i32 0}
 !3 = metadata !{metadata !5}
 !5 = metadata !{i32 786478, metadata !6, metadata !"foo", metadata !"foo", metadata !"", metadata !6, i32 5, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void ()* @foo, null, null, metadata !1, i32 5} ; [ DW_TAG_subprogram ]
 !6 = metadata !{i32 786473, metadata !32} ; [ DW_TAG_file_type ]
 !7 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !8, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
 !8 = metadata !{null}
-!9 = metadata !{i32 786449, metadata !32, i32 12, metadata !"clang version 3.2 (trunk 156513)", i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !10, metadata !1, metadata !""} ; [ DW_TAG_compile_unit ]
+!9 = metadata !{i32 786449, metadata !32, i32 12, metadata !"clang version 3.2 (trunk 156513)", i1 true, metadata !"", i32 0, metadata !1, metadata !1, metadata !10, metadata !1, metadata !1, metadata !""} ; [ DW_TAG_compile_unit ]
 !10 = metadata !{metadata !12}
 !12 = metadata !{i32 786478, metadata !6, metadata !"main", metadata !"main", metadata !"", metadata !6, i32 11, metadata !13, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, i32 (i32, i8**)* @main, null, null, metadata !19, i32 11} ; [ DW_TAG_subprogram ]
 !13 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !14, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]