path: root/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 GRCoreEngineImpl;
class ExplodedNodeImpl;
class CFG;
class ASTContext;

class GRStmtNodeBuilderImpl;
class GRBranchNodeBuilderImpl;
class GRIndirectGotoNodeBuilderImpl;
class GRSwitchNodeBuilderImpl;
class GREndPathNodebuilderImpl;  

class ExplodedNodeImpl : public llvm::FoldingSetNode {
protected:
  friend class ExplodedGraphImpl;
  friend class GRCoreEngineImpl;
  friend class GRStmtNodeBuilderImpl;
  friend class GRBranchNodeBuilderImpl;
  friend class GRIndirectGotoNodeBuilderImpl;
  friend class GRSwitchNodeBuilderImpl;
  friend class GREndPathNodeBuilderImpl;  
  
  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);
    }

    ExplodedNodeImpl* getNode() const {
      return reinterpret_cast<ExplodedNodeImpl*>(getPtr());
    }
    
  public:
    NodeGroup() : P(0) {}
    
    ~NodeGroup();
    
    ExplodedNodeImpl** begin() const;
    
    ExplodedNodeImpl** end() const;
    
    unsigned size() const;
    
    bool empty() const { return size() == 0; }
    
    void addNode(ExplodedNodeImpl* 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. Normally this value
  ///  is immutable, but we anticipate there will be times when algorithms
  ///  that directly manipulate the analysis graph will need to change it.
  void* State;
  
  /// Preds - The predecessors of this node.
  NodeGroup Preds;
  
  /// Succs - The successors of this node.
  NodeGroup Succs;
  
  /// Construct a ExplodedNodeImpl with the provided location and state.
  explicit ExplodedNodeImpl(const ProgramPoint& loc, void* state)
  : Location(loc), State(state) {}
  
  /// addPredeccessor - Adds a predecessor to the current node, and 
  ///  in tandem add this node as a successor of the other node.
  void addPredecessor(ExplodedNodeImpl* V) {
    assert (!V->isSink());
    Preds.addNode(V);
    V->Succs.addNode(this);
  }
  
public:
  
  /// getLocation - Returns the edge associated with the given node.
  ProgramPoint getLocation() const { return Location; }
  
  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(); }  
};


template <typename StateTy>
struct GRTrait {
  static inline void Profile(llvm::FoldingSetNodeID& ID, const StateTy* St) {
    St->Profile(ID);
  }
};


template <typename StateTy>
class ExplodedNode : public ExplodedNodeImpl {
public:
  /// Construct a ExplodedNodeImpl with the given node ID, program edge,
  ///  and state.
  explicit ExplodedNode(const ProgramPoint& loc, StateTy* St)
    : ExplodedNodeImpl(loc, St) {}
  
  /// getState - Returns the state associated with the node.  
  inline StateTy* getState() const {
    return static_cast<StateTy*>(State);
  }
  
  // Profiling (for FoldingSet).
  
  static inline void Profile(llvm::FoldingSetNodeID& ID,
                             const ProgramPoint& Loc,
                             StateTy* state) {
    ID.Add(Loc);
    GRTrait<StateTy>::Profile(ID, state);
  }
  
  inline void Profile(llvm::FoldingSetNodeID& ID) const {
    Profile(ID, getLocation(), getState());
  }
  
  void addPredecessor(ExplodedNode* V) {
    ExplodedNodeImpl::addPredecessor(V);
  }
  
  // Iterators over successor and predecessor vertices.
  typedef ExplodedNode**       succ_iterator;
  typedef const ExplodedNode** const_succ_iterator;
  typedef ExplodedNode**       pred_iterator;
  typedef const ExplodedNode** const_pred_iterator;

  pred_iterator pred_begin() { return (ExplodedNode**) Preds.begin(); }
  pred_iterator pred_end() { return (ExplodedNode**) 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 (ExplodedNode**) Succs.begin(); }
  succ_iterator succ_end() { return (ExplodedNode**) 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();
  }
};


class ExplodedGraphImpl {
protected:
  friend class GRCoreEngineImpl;
  friend class GRStmtNodeBuilderImpl;
  friend class GRBranchNodeBuilderImpl;
  friend class GRIndirectGotoNodeBuilderImpl;
  friend class GRSwitchNodeBuilderImpl;
  friend class GREndPathNodeBuilderImpl;
  
  // Type definitions.
  typedef llvm::SmallVector<ExplodedNodeImpl*,2>    RootsTy;
  typedef llvm::SmallVector<ExplodedNodeImpl*,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;
  
  /// 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;

  /// getNodeImpl - Retrieve the node associated with a (Location,State)
  ///  pair, where 'State' is represented as an opaque void*.  This method
  ///  is intended to be used only by GRCoreEngineImpl.
  virtual ExplodedNodeImpl* getNodeImpl(const ProgramPoint& L, void* State,
                                        bool* IsNew) = 0;
  
  virtual ExplodedGraphImpl* MakeEmptyGraph() const = 0;

  /// addRoot - Add an untyped node to the set of roots.
  ExplodedNodeImpl* addRoot(ExplodedNodeImpl* V