DebugInfo: Gut DICompileUnit and DIFile

Continuing gutting `DIDescriptor` subclasses; this edition,
`DICompileUnit` and `DIFile`.  In the name of PR23080.

llvm-svn: 235055
diff --git a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 5791ae1..368a81d 100644
--- a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -437,7 +437,7 @@
     }
   }
 
-  SmallString<128> Filename = CU.getFilename();
+  SmallString<128> Filename = CU->getFilename();
   sys::path::replace_extension(Filename, NewStem);
   StringRef FName = sys::path::filename(Filename);
   SmallString<128> CurPath;