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diff --git a/include/clang/Analysis/CallGraph.h b/include/clang/Analysis/CallGraph.h
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+//== CallGraph.h - AST-based Call graph  ------------------------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file declares the AST-based CallGraph.
+//
+//  A call graph for functions whose definitions/bodies are available in the
+//  current translation unit. The graph has a "virtual" root node that contains
+//  edges to all externally available functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_ANALYSIS_CALLGRAPH
+#define LLVM_CLANG_ANALYSIS_CALLGRAPH
+
+#include "clang/AST/DeclBase.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/SetVector.h"
+
+namespace clang {
+class CallGraphNode;
+
+/// \class The AST-based call graph.
+///
+/// The call graph extends itself with the given declarations by implementing
+/// the recursive AST visitor, which constructs the graph by visiting the given
+/// declarations.
+class CallGraph : public RecursiveASTVisitor<CallGraph> {
+  friend class CallGraphNode;
+
+  typedef llvm::DenseMap<const Decl *, CallGraphNode *> FunctionMapTy;
+
+  /// FunctionMap owns all CallGraphNodes.
+  FunctionMapTy FunctionMap;
+
+  /// This is a virtual root node that has edges to all the global functions -
+  /// 'main' or functions accessible from other translation units.
+  CallGraphNode *Root;
+
+  /// The list of nodes that have no parent. These are unreachable from Root.
+  /// Declarations can get to this list due to impressions in the graph, for
+  /// example, we do not track functions whose addresses were taken.
+  llvm::SetVector<CallGraphNode *> ParentlessNodes;
+
+public:
+  CallGraph();
+  ~CallGraph();
+
+  /// \brief Populate the call graph with the functions in the given
+  /// declaration.
+  ///
+  /// Recursively walks the declaration to find all the dependent Decls as well.
+  void addToCallGraph(Decl *D) {
+    TraverseDecl(D);
+  }
+
+  /// \brief Determine if a declaration should be included in the graph.
+  static bool includeInGraph(const Decl *D);
+
+  /// \brief Lookup the node for the given declaration.
+  CallGraphNode *getNode(const Decl *) const;
+
+  /// \brief Lookup the node for the given declaration. If none found, insert
+  /// one into the graph.
+  CallGraphNode *getOrInsertNode(Decl *);
+
+  /// Iterators through all the elements in the graph. Note, this gives
+  /// non-deterministic order.
+  typedef FunctionMapTy::iterator iterator;
+  typedef FunctionMapTy::const_iterator const_iterator;
+  iterator begin() { return FunctionMap.begin(); }
+  iterator end()   { return FunctionMap.end();   }
+  const_iterator begin() const { return FunctionMap.begin(); }
+  const_iterator end()   const { return FunctionMap.end();   }
+
+  /// \brief Get the number of nodes in the graph.
+  unsigned size() const { return FunctionMap.size(); }
+
+  /// \ brief Get the virtual root of the graph, all the functions available
+  /// externally are represented as callees of the node.
+  CallGraphNode *getRoot() const { return Root; }
+
+  /// Iterators through all the nodes of the graph that have no parent. These
+  /// are the unreachable nodes, which are either unused or are due to us
+  /// failing to add a call edge due to the analysis imprecision.
+  typedef llvm::SetVector<CallGraphNode *>::iterator nodes_iterator;
+  typedef llvm::SetVector<CallGraphNode *>::const_iterator const_nodes_iterator;
+  nodes_iterator parentless_begin() { return ParentlessNodes.begin(); }
+  nodes_iterator parentless_end() { return ParentlessNodes.end(); }
+  const_nodes_iterator
+    parentless_begin() const { return ParentlessNodes.begin(); }
+  const_nodes_iterator
+    parentless_end() const { return ParentlessNodes.end(); }
+
+  void print(raw_ostream &os) const;
+  void dump() const;
+  void viewGraph() const;
+
+  /// Part of recursive declaration visitation.
+  bool VisitFunctionDecl(FunctionDecl *FD) {
+    // We skip function template definitions, as their semantics is
+    // only determined when they are instantiated.
+    if (includeInGraph(FD))
+      // If this function has external linkage, anything could call it.
+      // Note, we are not precise here. For example, the function could have
+      // its address taken.
+      addNodeForDecl(FD, FD->isGlobal());
+    return true;
+  }
+
+  /// Part of recursive declaration visitation.
+  bool VisitObjCMethodDecl(ObjCMethodDecl *MD) {
+    if (includeInGraph(MD))
+      addNodeForDecl(MD, true);
+    return true;
+  }
+
+private:
+  /// \brief Add the given declaration to the call graph.
+  void addNodeForDecl(Decl *D, bool IsGlobal);
+
+  /// \brief Allocate a new node in the graph.
+  CallGraphNode *allocateNewNode(Decl *);
+};
+
+class CallGraphNode {
+public:
+  typedef CallGraphNode* CallRecord;
+
+private:
+  /// \brief The function/method declaration.
+  Decl *FD;
+
+  /// \brief The list of functions called from this node.
+  // Small vector might be more efficient since we are only tracking functions
+  // whose definition is in the current TU.
+  llvm::SmallVector<CallRecord, 5> CalledFunctions;
+
+public:
+  CallGraphNode(Decl *D) : FD(D) {}
+
+  typedef llvm::SmallVector<CallRecord, 5>::iterator iterator;
+  typedef llvm::SmallVector<CallRecord, 5>::const_iterator const_iterator;
+
+  /// Iterators through all the callees/children of the node.
+  inline iterator begin() { return CalledFunctions.begin(); }
+  inline iterator end()   { return CalledFunctions.end(); }
+  inline const_iterator begin() const { return CalledFunctions.begin(); }
+  inline const_iterator end()   const { return CalledFunctions.end();   }
+
+  inline bool empty() const {return CalledFunctions.empty(); }
+  inline unsigned size() const {return CalledFunctions.size(); }
+
+  void addCallee(CallGraphNode *N, CallGraph *CG) {
+    CalledFunctions.push_back(N);
+    CG->ParentlessNodes.remove(N);
+  }
+
+  Decl *getDecl() const { return FD; }
+
+  StringRef getName() const;
+
+  void print(raw_ostream &os) const;
+  void dump() const;
+};
+
+} // end clang namespace
+
+// Graph traits for iteration, viewing.
+namespace llvm {
+template <> struct GraphTraits<clang::CallGraphNode*> {
+  typedef clang::CallGraphNode NodeType;
+  typedef clang::CallGraphNode::CallRecord CallRecordTy;
+  typedef std::pointer_to_unary_function<CallRecordTy,
+                                         clang::CallGraphNode*> CGNDerefFun;
+  static NodeType *getEntryNode(clang::CallGraphNode *CGN) { return CGN; }
+  typedef mapped_iterator<NodeType::iterator, CGNDerefFun> ChildIteratorType;
+  static inline ChildIteratorType child_begin(NodeType *N) {
+    return map_iterator(N->begin(), CGNDerefFun(CGNDeref));
+  }
+  static inline ChildIteratorType child_end  (NodeType *N) {
+    return map_iterator(N->end(), CGNDerefFun(CGNDeref));
+  }
+  static clang::CallGraphNode *CGNDeref(CallRecordTy P) {
+    return P;
+  }
+};
+
+template <> struct GraphTraits<const clang::CallGraphNode*> {
+  typedef const clang::CallGraphNode NodeType;
+  typedef NodeType::const_iterator ChildIteratorType;
+  static NodeType *getEntryNode(const clang::CallGraphNode *CGN) { return CGN; }
+  static inline ChildIteratorType child_begin(NodeType *N) { return N->begin();}
+  static inline ChildIteratorType child_end  (NodeType *N) { return N->end(); }
+};
+
+template <> struct GraphTraits<clang::CallGraph*>
+  : public GraphTraits<clang::CallGraphNode*> {
+
+  static NodeType *getEntryNode(clang::CallGraph *CGN) {
+    return CGN->getRoot();  // Start at the external node!
+  }
+  typedef std::pair<const clang::Decl*, clang::CallGraphNode*> PairTy;
+  typedef std::pointer_to_unary_function<PairTy, clang::CallGraphNode&> DerefFun;
+  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
+  typedef mapped_iterator<clang::CallGraph::iterator, DerefFun> nodes_iterator;
+
+  static nodes_iterator nodes_begin(clang::CallGraph *CG) {
+    return map_iterator(CG->begin(), DerefFun(CGdereference));
+  }
+  static nodes_iterator nodes_end  (clang::CallGraph *CG) {
+    return map_iterator(CG->end(), DerefFun(CGdereference));
+  }
+  static clang::CallGraphNode &CGdereference(PairTy P) {
+    return *(P.second);
+  }
+
+  static unsigned size(clang::CallGraph *CG) {
+    return CG->size();
+  }
+};
+
+template <> struct GraphTraits<const clang::CallGraph*> :
+  public GraphTraits<const clang::CallGraphNode*> {
+  static NodeType *getEntryNode(const clang::CallGraph *CGN) {
+    return CGN->getRoot();
+  }
+  typedef std::pair<const clang::Decl*, clang::CallGraphNode*> PairTy;
+  typedef std::pointer_to_unary_function<PairTy, clang::CallGraphNode&> DerefFun;
+  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
+  typedef mapped_iterator<clang::CallGraph::const_iterator,
+                          DerefFun> nodes_iterator;
+
+  static nodes_iterator nodes_begin(const clang::CallGraph *CG) {
+    return map_iterator(CG->begin(), DerefFun(CGdereference));
+  }
+  static nodes_iterator nodes_end(const clang::CallGraph *CG) {
+    return map_iterator(CG->end(), DerefFun(CGdereference));
+  }
+  static clang::CallGraphNode &CGdereference(PairTy P) {
+    return *(P.second);
+  }
+
+  static unsigned size(const clang::CallGraph *CG) {
+    return CG->size();
+  }
+};
+
+} // end llvm namespace
+
+#endif