Unweaken vtables as per http://llvm.org/docs/CodingStandards.html#ll_virtual_anch

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146960 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DominanceFrontier.cpp b/lib/Analysis/DominanceFrontier.cpp
index 6de4e1e..1604576 100644
--- a/lib/Analysis/DominanceFrontier.cpp
+++ b/lib/Analysis/DominanceFrontier.cpp
@@ -35,6 +35,8 @@
   };
 }
 
+void DominanceFrontier::anchor() { }
+
 const DominanceFrontier::DomSetType &
 DominanceFrontier::calculate(const DominatorTree &DT,
                              const DomTreeNode *Node) {