DwarfCompileUnit: Add type safety to CompileUnit::getNode by returning DICompileUnit instead of a raw MDNode*.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194895 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 5b6d33f..059f2be 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -101,7 +101,7 @@
   // Accessors.
   unsigned getUniqueID() const { return UniqueID; }
   uint16_t getLanguage() const { return Node.getLanguage(); }
-  const MDNode *getNode() const { return Node; }
+  DICompileUnit getNode() const { return Node; }
   DIE *getCUDie() const { return CUDie.get(); }
   const StringMap<DIE *> &getGlobalNames() const { return GlobalNames; }
   const StringMap<DIE *> &getGlobalTypes() const { return GlobalTypes; }