Add a trackIfUnresolved to DIBuilder::createInheritance(),
tested via the clang test CodeGenCXX/vtable-holder-self-reference.cpp .

llvm-svn: 228853
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 6c38197..5cdb6a6 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -415,7 +415,9 @@
                           .concat(Flags)
                           .get(VMContext),
                       nullptr, Ty.getRef(), BaseTy.getRef()};
-  return DIDerivedType(MDNode::get(VMContext, Elts));
+  auto R = DIDerivedType(MDNode::get(VMContext, Elts));
+  trackIfUnresolved(R);
+  return R;
 }
 
 DIDerivedType DIBuilder::createMemberType(DIDescriptor Scope, StringRef Name,