Index: llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h
+++ llvm/trunk/include/llvm/CodeGen/ScheduleDAG.h
@@ -680,6 +680,7 @@
 
   template <> struct GraphTraits<SUnit*> {
     typedef SUnit NodeType;
+    typedef SUnit *NodeRef;
     typedef SUnitIterator ChildIteratorType;
     static inline NodeType *getEntryNode(SUnit *N) { return N; }
     static inline ChildIteratorType child_begin(NodeType *N) {
Index: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -2056,6 +2056,7 @@
 
 template <> struct GraphTraits<SDNode*> {
   typedef SDNode NodeType;
+  typedef SDNode *NodeRef;
   typedef SDNodeIterator ChildIteratorType;
   static inline NodeType *getEntryNode(SDNode *N) { return N; }
   static inline ChildIteratorType child_begin(NodeType *N) {
Index: llvm/trunk/include/llvm/Support/GraphWriter.h
===================================================================
--- llvm/trunk/include/llvm/Support/GraphWriter.h
+++ llvm/trunk/include/llvm/Support/GraphWriter.h
@@ -59,14 +59,19 @@
 
   typedef DOTGraphTraits<GraphType>           DOTTraits;
   typedef GraphTraits<GraphType>              GTraits;
-  typedef typename GTraits::NodeType          NodeType;
+  typedef typename GTraits::NodeRef           NodeRef;
   typedef typename GTraits::nodes_iterator    node_iterator;
   typedef typename GTraits::ChildIteratorType child_iterator;
   DOTTraits DTraits;
 
+  static_assert(std::is_pointer<NodeRef>::value,
+                "FIXME: Currently GraphWriter requires the NodeRef type to be "
+                "a pointer.\nThe pointer usage should be moved to "
+                "DOTGraphTraits, and removed from GraphWriter itself.");
+
   // Writes the edge labels of the node to O and returns true if there are any
   // edge labels not equal to the empty string "".
-  bool getEdgeSourceLabels(raw_ostream &O, NodeType *Node) {
+  bool getEdgeSourceLabels(raw_ostream &O, NodeRef Node) {
     child_iterator EI = GTraits::child_begin(Node);
     child_iterator EE = GTraits::child_end(Node);
     bool hasEdgeSourceLabels = false;
@@ -140,31 +145,23 @@
     // Loop over the graph, printing it out...
     for (node_iterator I = GTraits::nodes_begin(G), E = GTraits::nodes_end(G);
          I != E; ++I)
-      if (!isNodeHidden(*I))
-        writeNode(*I);
-  }
-
-  bool isNodeHidden(NodeType &Node) {
-    return isNodeHidden(&Node);
+      if (!isNodeHidden(&*I))
+        writeNode(&*I);
   }
 
-  bool isNodeHidden(NodeType *const *Node) {
+  bool isNodeHidden(NodeRef const *Node) {
     return isNodeHidden(*Node);
   }
 
-  bool isNodeHidden(NodeType *Node) {
+  bool isNodeHidden(NodeRef Node) {
     return DTraits.isNodeHidden(Node);
   }
 
-  void writeNode(NodeType& Node) {
-    writeNode(&Node);
-  }
-
-  void writeNode(NodeType *const *Node) {
+  void writeNode(NodeRef const *Node) {
     writeNode(*Node);
   }
 
-  void writeNode(NodeType *Node) {
+  void writeNode(NodeRef Node) {
     std::string NodeAttributes = DTraits.getNodeAttributes(Node, G);
 
     O << "\tNode" << static_cast<const void*>(Node) << " [shape=record,";
@@ -237,8 +234,8 @@
         writeEdge(Node, 64, EI);
   }
 
-  void writeEdge(NodeType *Node, unsigned edgeidx, child_iterator EI) {
-    if (NodeType *TargetNode = *EI) {
+  void writeEdge(NodeRef Node, unsigned edgeidx, child_iterator EI) {
+    if (NodeRef TargetNode = *EI) {
       int DestPort = -1;
       if (DTraits.edgeTargetsEdgeSource(Node, EI)) {
         child_iterator TargetIt = DTraits.getEdgeTarget(Node, EI);
Index: llvm/trunk/lib/Analysis/BlockFrequencyInfo.cpp
===================================================================
--- llvm/trunk/lib/Analysis/BlockFrequencyInfo.cpp
+++ llvm/trunk/lib/Analysis/BlockFrequencyInfo.cpp
@@ -61,6 +61,7 @@
 template <>
 struct GraphTraits<BlockFrequencyInfo *> {
   typedef const BasicBlock NodeType;
+  typedef const BasicBlock *NodeRef;
   typedef succ_const_iterator ChildIteratorType;
   typedef Function::const_iterator nodes_iterator;
 
Index: llvm/trunk/lib/CodeGen/MachineBlockFrequencyInfo.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/MachineBlockFrequencyInfo.cpp
+++ llvm/trunk/lib/CodeGen/MachineBlockFrequencyInfo.cpp
@@ -53,6 +53,7 @@
 
 template <> struct GraphTraits<MachineBlockFrequencyInfo *> {
   typedef const MachineBasicBlock NodeType;
+  typedef const MachineBasicBlock *NodeRef;
   typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
   typedef MachineFunction::const_iterator nodes_iterator;