Use 'override/final' instead of 'virtual' for overridden methods

The patch is generated using clang-tidy misc-use-override check.

This command was used:

  tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
    -checks='-*,misc-use-override' -header-filter='llvm|clang' \
    -j=32 -fix -format

http://reviews.llvm.org/D8925

llvm-svn: 234679
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 46a5df3..4ff0b9f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2560,7 +2560,7 @@
     SelectionDAG::DAGUpdateListener(DAG),
     RecordedNodes(RN), MatchScopes(MS) { }
 
-  void NodeDeleted(SDNode *N, SDNode *E) {
+  void NodeDeleted(SDNode *N, SDNode *E) override {
     // Some early-returns here to avoid the search if we deleted the node or
     // if the update comes from MorphNodeTo (MorphNodeTo is the last thing we
     // do, so it's unnecessary to update matching state at that point).