include/clang/Analysis/PathSensitive/ExplodedGraph.h

//=-- ExplodedGraph.h - Local, Path-Sens. "Exploded 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 defines the template classes ExplodedNode and ExplodedGraph,
//  which represent a path-sensitive, intra-procedural "exploded graph."
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_ANALYSIS_EXPLODEDGRAPH
#define LLVM_CLANG_ANALYSIS_EXPLODEDGRAPH

#include "clang/Analysis/ProgramPoint.h"
#include "clang/AST/Decl.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Allocator.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/Support/Casting.h"

namespace clang {

class GRState;
class CFG;
class ASTContext;

//===----------------------------------------------------------------------===//
// ExplodedGraph "implementation" classes.  These classes are not typed to
// contain a specific kind of state.  Typed-specialized versions are defined
// on top of these classes.
//===----------------------------------------------------------------------===//
  
class ExplodedNode : public llvm::FoldingSetNode {
  friend class ExplodedGraph;
  friend class GRCoreEngine;
  friend class GRStmtNodeBuilder;
  friend class GRBranchNodeBuilder;
  friend class GRIndirectGotoNodeBuilder;
  friend class GRSwitchNodeBuilder;
  friend class GREndPathNodeBuilder;  
  
  class NodeGroup {
    enum { Size1 = 0x0, SizeOther = 0x1, AuxFlag = 0x2, Mask = 0x3 };
    uintptr_t P;
    
    unsigned getKind() const {
      return P & 0x1;
    }
    
    void* getPtr() const {
      assert (!getFlag());
      return reinterpret_cast<void*>(P & ~Mask);
    }

    ExplodedNode *getNode() const {
      return reinterpret_cast<ExplodedNode*>(getPtr());
    }
    
  public:
    NodeGroup() : P(0) {}
    
    ~NodeGroup();
    
    ExplodedNode** begin() const;
    
    ExplodedNode** end() const;
    
    unsigned size() const;
    
    bool empty() const { return size() == 0; }
    
    void addNode(ExplodedNode* N);
    
    void setFlag() {
      assert (P == 0);
      P = AuxFlag;
    }
    
    bool getFlag() const {
      return P & AuxFlag ? true : false;
    }
  };  
  
  /// Location - The program location (within a function body) associated
  ///  with this node.
  const ProgramPoint Location;
  
  /// State - The state associated with this node.
  const GRState* State;
  
  /// Preds - The predecessors of this node.
  NodeGroup Preds;
  
  /// Succs - The successors of this node.
  NodeGroup Succs;

public:

  explicit ExplodedNode(const ProgramPoint& loc, const GRState* state) 
    : Location(loc), State(state) {}

  /// getLocation - Returns the edge associated with the given node.
  ProgramPoint getLocation() const { return Location; }

  const LocationContext *getLocationContext() const { 
    return getLocation().getLocationContext(); 
  }

  const GRState* getState() const {
    return State;
  }

  template <typename T>
  const T* getLocationAs() const { return llvm::dyn_cast<T>(&Location); }

  static void Profile(llvm::FoldingSetNodeID &ID, 
                      const ProgramPoint& Loc, const GRState* state);

  void Profile(llvm::FoldingSetNodeID& ID) const {
    Profile(ID, getLocation(), getState());
  }

  /// addPredeccessor - Adds a predecessor to the current node, and 
  ///  in tandem add this node as a successor of the other node.
  void addPredecessor(ExplodedNode* V);

  unsigned succ_size() const { return Succs.size(); }
  unsigned pred_size() const { return Preds.size(); }
  bool succ_empty() const { return Succs.empty(); }
  bool pred_empty() const { return Preds.empty(); }
  
  bool isSink() const { return Succs.getFlag(); }
  void markAsSink() { Succs.setFlag(); } 

  ExplodedNode* getFirstPred() {
    return pred_empty() ? NULL : *(pred_begin());
  }
  
  const ExplodedNode* getFirstPred() const {
    return const_cast<ExplodedNode*>(this)->getFirstPred();
  }
  
  // Iterators over successor and predecessor vertices.
  typedef ExplodedNode**       succ_iterator;
  typedef const ExplodedNode* const * const_succ_iterator;
  typedef ExplodedNode**       pred_iterator;
  typedef const ExplodedNode* const * const_pred_iterator;

  pred_iterator pred_begin() { return Preds.begin(); }
  pred_iterator pred_end() { return Preds.end(); }

  const_pred_iterator pred_begin() const {
    return const_cast<ExplodedNode*>(this)->pred_begin();
  }  
  const_pred_iterator pred_end() const {
    return const_cast<ExplodedNode*>(this)->pred_end();
  }

  succ_iterator succ_begin() { return Succs.begin(); }
  succ_iterator succ_end() { return Succs.end(); }

  const_succ_iterator succ_begin() const {
    return const_cast<ExplodedNode*>(this)->succ_begin();
  }
  const_succ_iterator succ_end() const {
    return const_cast<ExplodedNode*>(this)->succ_end();
  }

  // For debugging.
  
public:
  
  class Auditor {
  public:
    virtual ~Auditor();
    virtual void AddEdge(ExplodedNode* Src, ExplodedNode* Dst) = 0;
  };
  
  static void SetAuditor(Auditor* A);
};

// FIXME: Is this class necessary?
class InterExplodedGraphMap {
  llvm::DenseMap<const ExplodedNode*, ExplodedNode*> M;
  friend class ExplodedGraph;  

public:
  ExplodedNode* getMappedNode(const ExplodedNode* N) const;
  
  InterExplodedGraphMap() {};
  virtual ~InterExplodedGraphMap() {}
};

class ExplodedGraph {
protected:
  friend class GRCoreEngine;

  // Type definitions.
  typedef llvm::SmallVector<ExplodedNode*,2>    RootsTy;
  typedef llvm::SmallVector<ExplodedNode*,10>   EndNodesTy;
    
  /// Roots - The roots of the simulation graph. Usually there will be only
  /// one, but clients are free to establish multiple subgraphs within a single
  /// SimulGraph. Moreover, these subgraphs can often merge when paths from
  /// different roots reach the same state at the same program location.
  RootsTy Roots;

  /// EndNodes - The nodes in the simulation graph which have been
  ///  specially marked as the endpoint of an abstract simulation path.
  EndNodesTy EndNodes;

  /// Nodes - The nodes in the graph.
  llvm::FoldingSet<ExplodedNode> Nodes;

  /// Allocator - BumpPtrAllocator to create nodes.
  llvm::BumpPtrAllocator Allocator;
  
  /// cfg - The CFG associated with this analysis graph.
  CFG& cfg;
  
  /// CodeDecl - The declaration containing the code being analyzed.  This
  ///  can be a FunctionDecl or and ObjCMethodDecl.
  Decl& CodeDecl;
  
  /// Ctx - The ASTContext used to "interpret" CodeDecl.
  ASTContext& Ctx;
  
  /// NumNodes - The number of nodes in the graph.
  unsigned NumNodes;

public:
  /// getNode - Retrieve the node associated with a (Location,State) pair,
  ///  where the 'Location' is a ProgramPoint in the CFG.  If no node for
  ///  this pair exists, it is created.  IsNew is set to true if
  ///  the node was freshly created.

  ExplodedNode* getNode(const ProgramPoint& L, const GRState *State,
                        bool* IsNew = 0);
  
  ExplodedGraph* MakeEmptyGraph() const {
    return new ExplodedGraph(cfg, CodeDecl, Ctx);
  }

  /// addRoot - Add an untyped node to the set of roots.
  ExplodedNode* addRoot(ExplodedNode* V) {
    Roots.push_back(V);
    return V;
  }

  /// addEndOfPath - Add an untyped node to the set of EOP nodes.
  ExplodedNode* addEndOfPath(ExplodedNode* V) {
    EndNodes.push_back(V);
    return V;
  }

  ExplodedGraph(CFG& c, Decl& cd, ASTContext& ctx)
    : cfg(c), CodeDecl(cd), Ctx(ctx), NumNodes(0) {}

  virtual ~ExplodedGraph() {}

  unsigned num_roots() const { return Roots.size(); }
  unsigned num_eops() const { return EndNodes.size(); }
  
  bool empty() const { return NumNodes == 0; }
  unsigned size() const { return NumNodes; }

  // Iterators.
  typedef ExplodedNode                        NodeTy;
  typedef llvm::FoldingSet<ExplodedNode>      AllNodesTy;
  typedef NodeTy**                            roots_iterator;
  typedef NodeTy* const *                     const_roots_iterator;
  typedef NodeTy**                            eop_iterator;
  typedef NodeTy* const *                     const_eop_iterator;
  typedef AllNodesTy::iterator                node_iterator;
  typedef AllNodesTy::const_iterator          const_node_iterator;
  
  node_iterator nodes_begin() { return Nodes.begin(); }

  node_iterator nodes_end() { return Nodes.end(); }
  
  const_node_iterator nodes_begin() const { return Nodes.begin(); }
  
  const_node_iterator nodes_end() const { return Nodes.end(); }
  
  roots_iterator roots_begin() { return Roots.begin(); }
  
  roots_iterator roots_end() { return Roots.end(); }
  
  const_roots_iterator roots_begin() const { return Roots.begin(); }
  
  const_roots_iterator roots_end() const { return Roots.end(); }  

  eop_iterator eop_begin() { return EndNodes.begin(); }
    
  eop_iterator eop_end() { return EndNodes.end(); }
  
  const_eop_iterator eop_begin() const { return EndNodes.begin(); }
  
  const_eop_iterator eop_end() const { return EndNodes.end(); }

  llvm::BumpPtrAllocator& getAllocator() { return Allocator; }
  CFG& getCFG() { return cfg; }
  ASTContext& getContext() { return Ctx; }

  Decl& getCodeDecl() { return CodeDecl; }
  const Decl& getCodeDecl() const { return CodeDecl; }

  const FunctionDecl* getFunctionDecl() const {
    return llvm::dyn_cast<FunctionDecl>(&CodeDecl);
  }
  
  typedef llvm::DenseMap<const ExplodedNode*, ExplodedNode*> NodeMap;

  std::pair<ExplodedGraph*, InterExplodedGraphMap*>
  Trim(const NodeTy* const* NBeg, const NodeTy* const* NEnd,
       llvm::DenseMap<const void*, const void*> *InverseMap = 0) const;

  ExplodedGraph* TrimInternal(const ExplodedNode* const * NBeg,
                              const ExplodedNode* const * NEnd,
                              InterExplodedGraphMap *M,
                    llvm::DenseMap<const void*, const void*> *InverseMap) const;
};

class ExplodedNodeSet {
  typedef llvm::SmallPtrSet<ExplodedNode*,5> ImplTy;
  ImplTy Impl;
  
public:
  ExplodedNodeSet(ExplodedNode* N) {
    assert (N && !static_cast<ExplodedNode*>(N)->isSink());
    Impl.insert(N);
  }
  
  ExplodedNodeSet() {}
  
  inline void Add(ExplodedNode* N) {
    if (N && !static_cast<ExplodedNode*>(N)->isSink()) Impl.insert(N);
  }
  
  ExplodedNodeSet& operator=(const ExplodedNodeSet &X) {
    Impl = X.Impl;
    return *this;
  }
  
  typedef ImplTy::iterator       iterator;
  typedef ImplTy::const_iterator const_iterator;

  inline unsigned size() const { return Impl.size();  }
  inline bool empty()    const { return Impl.empty(); }

  inline void clear() { Impl.clear(); }
  
  inline iterator begin() { return Impl.begin(); }
  inline iterator end()   { return Impl.end();   }
  
  inline const_iterator begin() const { return Impl.begin(); }
  inline const_iterator end()   const { return Impl.end();   }
};  
  
} // end clang namespace

// GraphTraits

namespace llvm {
  template<> struct GraphTraits<clang::ExplodedNode*> {
    typedef clang::ExplodedNode NodeType;
    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) {
      return N->succ_begin();
    }
    
    static inline ChildIteratorType child_end(NodeType* N) {
      return N->succ_end();
    }
    
    static inline nodes_iterator nodes_begin(NodeType* N) {
      return df_begin(N);
    }
    
    static inline nodes_iterator nodes_end(NodeType* N) {
      return df_end(N);
    }
  };
  
  template<> struct GraphTraits<const clang::ExplodedNode*> {
    typedef const clang::ExplodedNode NodeType;
    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) {
      return N->succ_begin();
    }
    
    static inline ChildIteratorType child_end(NodeType* N) {
      return N->succ_end();
    }
    
    static inline nodes_iterator nodes_begin(NodeType* N) {
      return df_begin(N);
    }
    
    static inline nodes_iterator nodes_end(NodeType* N) {
      return df_end(N);
    }
  };
  
} // end llvm namespace

#endif