[ADT] Migrate DepthFirstIterator to use NodeRef

[timshen]

Summary

The corresponding LLVM change is D23146.

include/clang/AST/StmtGraphTraits.h

 
 namespace llvm {
 
 //template <typename T> struct GraphTraits;
 
 
 template <> struct GraphTraits<clang::Stmt*> {
   typedef clang::Stmt                       NodeType;
+  typedef clang::Stmt *                     NodeRef;
   typedef clang::Stmt::child_iterator       ChildIteratorType;
   typedef llvm::df_iterator<clang::Stmt*>   nodes_iterator;
 
   static NodeType* getEntryNode(clang::Stmt* S) { return S; }
 
   static inline ChildIteratorType child_begin(NodeType* N) {
     if (N) return N->child_begin();
     else return ChildIteratorType();
template <> struct GraphTraits<clang::Stmt*> {
   static nodes_iterator nodes_end(clang::Stmt* S) {
     return df_end(S);
   }
 };
 
 
 template <> struct GraphTraits<const clang::Stmt*> {
   typedef const clang::Stmt                       NodeType;
+  typedef const clang::Stmt *                     NodeRef;
   typedef clang::Stmt::const_child_iterator       ChildIteratorType;
   typedef llvm::df_iterator<const clang::Stmt*>   nodes_iterator;
 
   static NodeType* getEntryNode(const clang::Stmt* S) { return S; }
 
   static inline ChildIteratorType child_begin(NodeType* N) {
     if (N) return N->child_begin();
     else return ChildIteratorType();

include/clang/Analysis/Analyses/Dominators.h

 
 //===-------------------------------------
 /// DominatorTree GraphTraits specialization so the DominatorTree can be
 /// iterable by generic graph iterators.
 ///
 namespace llvm {
 template <> struct GraphTraits< ::clang::DomTreeNode* > {
   typedef ::clang::DomTreeNode NodeType;
+  typedef ::clang::DomTreeNode *NodeRef;
   typedef NodeType::iterator  ChildIteratorType;
 
   static NodeType *getEntryNode(NodeType *N) {
     return N;
   }
   static inline ChildIteratorType child_begin(NodeType *N) {
     return N->begin();
   }

include/clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h

 
 } // end clang namespace
 
 // GraphTraits
 
 namespace llvm {
   template<> struct GraphTraits<clang::ento::ExplodedNode*> {
     typedef clang::ento::ExplodedNode NodeType;
+    typedef clang::ento::ExplodedNode *NodeRef;
     typedef NodeType::succ_iterator  ChildIteratorType;
     typedef llvm::df_iterator<NodeType*>      nodes_iterator;
 
     static inline NodeType* getEntryNode(NodeType* N) {
       return N;
     }
 
     static inline ChildIteratorType child_begin(NodeType* N) {
template<> struct GraphTraits<clang::ento::ExplodedNode*> {
 
     static inline nodes_iterator nodes_end(NodeType* N) {
       return df_end(N);
     }
   };
 
   template<> struct GraphTraits<const clang::ento::ExplodedNode*> {
     typedef const clang::ento::ExplodedNode NodeType;
+    typedef const clang::ento::ExplodedNode *NodeRef;
     typedef NodeType::const_succ_iterator   ChildIteratorType;
     typedef llvm::df_iterator<NodeType*>       nodes_iterator;
 
     static inline NodeType* getEntryNode(NodeType* N) {
       return N;
     }
 
     static inline ChildIteratorType child_begin(NodeType* N) {