path: root/stp/AST/AST.h

// -*- c++ -*-
/********************************************************************
 * AUTHORS: Vijay Ganesh, David L. Dill
 *
 * BEGIN DATE: November, 2005
 *
 * LICENSE: Please view LICENSE file in the home dir of this Program
 ********************************************************************/

#ifndef AST_H
#define AST_H
#include <vector>
#ifdef EXT_HASH_MAP
#include <ext/hash_set>
#include <ext/hash_map>
#else
#include <hash_set>
#include <hash_map>
#endif
#include <iostream>
#include <sstream>
#include <string>
#include <map>
#include <set>
#include "ASTUtil.h"
#include "ASTKind.h"
#include "../sat/Solver.h"
#include "../sat/SolverTypes.h"
#include <cstdlib>
#include <stdint.h>
#ifndef NATIVE_C_ARITH
#include "../constantbv/constantbv.h"
#endif
/*****************************************************************************
 * LIST OF CLASSES DECLARED IN THIS FILE:
 *
 * class BeevMgr;  
 * class ASTNode; 
 * class ASTInternal;  
 * class ASTInterior;  
 * class ASTSymbol;
 * class ASTBVConst;
 *****************************************************************************/
namespace BEEV {
  using namespace std; 
  using namespace MINISAT;
#ifdef EXT_HASH_MAP
  using namespace __gnu_cxx;
#endif

  //return types for the GetType() function in ASTNode class
  enum types {
    BOOLEAN_TYPE = 0,
    BITVECTOR_TYPE,
    ARRAY_TYPE,
    UNKNOWN_TYPE
  };
  
  class BeevMgr;  
  class ASTNode; 
  class ASTInternal;  
  class ASTInterior;  
  class ASTSymbol;
  class ASTBVConst;
  class BVSolver;

  //Vector of ASTNodes, used for child nodes among other things.  
  typedef vector<ASTNode> ASTVec;
  extern ASTVec _empty_ASTVec;
  extern BeevMgr * globalBeevMgr_for_parser;

  typedef unsigned int * CBV;

  /***************************************************************************/
  /*  Class ASTNode: Smart pointer to actual ASTNode internal datastructure. */
  /***************************************************************************/
  class ASTNode {
    friend class BeevMgr;
    friend class vector<ASTNode>;
    //Print the arguments in lisp format.
    friend ostream &LispPrintVec(ostream &os, 
				 const ASTVec &v, int indentation = 0); 

  private:
    // FIXME: make this into a reference?
    ASTInternal * _int_node_ptr;	// The real data.

    // Usual constructor.  
    ASTNode(ASTInternal *in);

    //Check if it points to a null node
    bool IsNull () const { return _int_node_ptr == NULL; }

    //Equal iff ASTIntNode pointers are the same.
    friend bool operator==(const ASTNode node1, const ASTNode node2){
      return ((size_t) node1._int_node_ptr) == ((size_t) node2._int_node_ptr);
    }
    
    /* FIXME:  Nondeterministic code *** */
    /** questionable pointer comparison function */
    friend bool operator<(const ASTNode node1, const ASTNode node2){
      return ((size_t) node1._int_node_ptr) < ((size_t) node2._int_node_ptr);
    }

  public:
    // This is for sorting by expression number (used in Boolean
    //optimization)
    friend bool exprless(const ASTNode n1, const ASTNode n2) {
      Kind k1 = n1.GetKind();
      Kind k2 = n2.GetKind();
      
      if(BVCONST == k1 && BVCONST != k2){
	return true;
      }
      if(BVCONST != k1 && BVCONST == k2){
	return false;
      }
      
      if(SYMBOL == k1 && SYMBOL != k2) {
      	return true;
      }
      
      if(SYMBOL != k1 && SYMBOL == k2) {
      	return false;
      }

      return (n1.GetNodeNum() < n2.GetNodeNum());
    }//end of exprless 
    
    // Internal lisp-form printer that does not clear _node_print_table
    ostream &LispPrint1(ostream &os, int indentation) const;

    ostream &LispPrint_indent(ostream &os, int indentation) const;

    // For lisp DAG printing.  Has it been printed already, so we can
    // just print the node number?
    bool IsAlreadyPrinted() const;
    void MarkAlreadyPrinted() const;

  public:
    // Default constructor.  This gets used when declaring an ASTVec
    // of a given size, in the hash table, etc.  For faster
    // refcounting, create a symbol node for NULL.  Give it a big
    // initial refcount.  Never free it.  also check, for ref-count
    // overflow?
    ASTNode() : _int_node_ptr(NULL) { };

    // Copy constructor
    ASTNode(const ASTNode &n);

    // Destructor
    ~ASTNode();

    // Assignment (for ref counting)
    ASTNode& operator=(const ASTNode& n);

    BeevMgr &GetBeevMgr() const;

    // Access node number
    int GetNodeNum() const;

    // Access kind.  Inlined later because of declaration ordering problems.
    Kind GetKind() const;

    // access Children
    const ASTVec &GetChildren() const;
    
    // Return the number of child nodes
    size_t Degree() const{ 
      return GetChildren().size(); 
    };    

    // Get indexth childNode.
    const ASTNode operator[](size_t index) const { 
      return GetChildren()[index]; 
    };    

    // Get begin() iterator for child nodes
    ASTVec::const_iterator begin() const{ 
      return GetChildren().begin(); 
    };  

    // Get end() iterator for child nodes
    ASTVec::const_iterator end() const{ 
      return GetChildren().end(); 
    };

    //Get back() element for child nodes
    const ASTNode back() const{
      return GetChildren().back();
    };  

    // Get the name from a symbol (char *).  It's an error if kind != SYMBOL
    const char *GetName() const;

    //Get the BVCONST value
#ifndef NATIVE_C_ARITH
    CBV GetBVConst() const;
#else
    unsigned long long int GetBVConst() const;
#endif

    /*ASTNode is of type BV <==> ((indexwidth=0)&&(valuewidth>0))
     *
     *ASTNode is of type ARRAY <==> ((indexwidth>0)&&(valuewidth>0))
     *
     *ASTNode is of type BOOLEAN <==> ((indexwidth=0)&&(valuewidth=0))
     *
     *both indexwidth and valuewidth should never be less than 0
     */
    unsigned int GetIndexWidth () const;

    // FIXME: This function is dangerous.  Try to eliminate it's use.
    void SetIndexWidth (unsigned int iw) const;

    unsigned int GetValueWidth () const;

    // FIXME: This function is dangerous.  Try to eliminate it's use.
    void SetValueWidth (unsigned int vw) const;

    //return the type of the ASTNode
    //0 iff BOOLEAN
    //1 iff BITVECTOR
    //2 iff ARRAY

    /*ASTNode is of type BV <==> ((indexwidth=0)&&(valuewidth>0))
     *
     *ASTNode is of type ARRAY <==> ((indexwidth>0)&&(valuewidth>0))
     *
     *ASTNode is of type BOOLEAN <==> ((indexwidth=0)&&(valuewidth=0))
     *
     *both indexwidth and valuewidth should never be less than 0
     */    
    types GetType(void) const;

    // Hash is pointer value of _int_node_ptr.
    size_t Hash() const{ 
      return (size_t) _int_node_ptr; 
      //return GetNodeNum(); 
    }

    // lisp-form printer 
    ostream& LispPrint(ostream &os, int indentation = 0) const;

    //Presentation Language Printer
    ostream& PL_Print(ostream &os, int indentation = 0) const;

    void PL_Print1(ostream &os, int indentation = 0, bool b = false) const;

    //Construct let variables for shared subterms
    void LetizeNode(void) const;

    // Attempt to define something that will work in the gdb
    friend void lp(ASTNode &node);
    friend void lpvec(const ASTVec &vec);

    friend ostream &operator<<(ostream &os, const ASTNode &node) { 
      node.LispPrint(os, 0); 
      return os; 
    };
    
    // Check whether the ASTNode points to anything.  Undefined nodes
    // are created by the default constructor.  In binding table (for
    // lambda args, etc.), undefined nodes are used to represent
    // deleted entries.
    bool IsDefined() const { return _int_node_ptr != NULL; }        

    /* Hasher class for STL hash_maps and hash_sets that use ASTNodes
     * as keys.  Needs to be public so people can define hash tables
     * (and use ASTNodeMap class)*/
    class ASTNodeHasher {
    public:
      size_t operator() (const ASTNode& n) const{ 
	return (size_t) n._int_node_ptr; 
	//return (size_t)n.GetNodeNum();
      };
    }; //End of ASTNodeHasher
  
    /* Equality for ASTNode hash_set and hash_map. Returns true iff
     * internal pointers are the same.  Needs to be public so people
     * can define hash tables (and use ASTNodeSet class)*/
    class ASTNodeEqual {
    public:
      bool operator()(const ASTNode& n1, const ASTNode& n2) const{ 
	return (n1._int_node_ptr == n2._int_node_ptr); 
      }
    }; //End of ASTNodeEqual
  }; //End of Class ASTNode

  void FatalError(const char * str, const ASTNode& a, int w = 0);
  void FatalError(const char * str);
  void SortByExprNum(ASTVec& c);
  bool exprless(const ASTNode n1, const ASTNode n2);
  bool isAtomic(Kind k);

  /***************************************************************************/
  /*  Class ASTInternal:Abstract base class for internal node representation.*/
  /*                    Requires Kind and ChildNodes so same traversal works */
  /*                    on all nodes.                                        */
  /***************************************************************************/
  class ASTInternal {

    friend class ASTNode;

  protected:    

    // reference count.
    int _ref_count;

    // Kind.  It's a type tag and the operator.
    Kind _kind;  

    // The vector of children (*** should this be in ASTInterior? ***)
    ASTVec _children;

    // Manager object.  Having this backpointer means it's easy to
    // find the manager when we need it.
    BeevMgr &_bm;

    //Nodenum is a unique positive integer for the node.  The nodenum
    //of a node should always be greater than its descendents (which
    //is easily achieved by incrementing the number each time a new
    //node is created).
    int _node_num;

    // Length of bitvector type for array index.  The term is an
    // array iff this is positive.  Otherwise, the term is a bitvector
    // or a bit.
    unsigned int _index_width;

    // Length of bitvector type for scalar value or array element.
    // If this is one, the term represents a single bit (same as a bitvector
    // of length 1).  It must be 1 or greater.
    unsigned int _value_width;

    // Increment refcount.
#ifndef SMTLIB
    void IncRef() { ++_ref_count; }
#else
    void IncRef() { }
#endif

    // DecRef is a potentially expensive, because it has to delete 
    // the node from the unique table, in addition to freeing it.
    // FIXME:  Consider putting in a backpointer (iterator) to the hash
    // table entry so it can be deleted without looking it up again.
    void DecRef();

    virtual Kind GetKind() const { return _kind; }

    virtual ASTVec const &GetChildren() const { return _children; }

    int GetNodeNum() const { return _node_num; }

    void SetNodeNum(int nn) { _node_num = nn; };

    // Constructor (bm only)
    ASTInternal(BeevMgr &bm, int nodenum = 0) :
      _ref_count(0),
      _kind(UNDEFINED),
      _bm(bm),
      _node_num(nodenum),
      _index_width(0),
      _value_width(0) { }

    // Constructor (kind only, empty children, int nodenum) 
    ASTInternal(Kind kind, BeevMgr &bm, int nodenum = 0) : 
      _ref_count(0),
      _kind(kind),
      _bm(bm),
      _node_num(nodenum),
      _index_width(0),
      _value_width(0) { } 

    // Constructor (kind and children).  This copies the contents of
    // the child nodes.
    // FIXME: is there a way to avoid repeating these?
    ASTInternal(Kind kind, const ASTVec &children, BeevMgr &bm, int nodenum = 0) : 
      _ref_count(0),
      _kind(kind),
      _children(children),
      _bm(bm),
      _node_num(nodenum),
      _index_width(0),
      _value_width(0) { } 

    // Copy constructor.  This copies the contents of the child nodes
    // array, along with everything else.  Assigning the smart pointer,
    // ASTNode, does NOT invoke this; This should only be used for 
    // temporary hash keys before uniquefication.
    // FIXME:  I don't think children need to be copied.
    ASTInternal(const ASTInternal &int_node, int nodenum = 0) :
      _ref_count(0),
      _kind(int_node._kind),
      _children(int_node._children),
      _bm(int_node._bm),
      _node_num(int_node._node_num), 
      _index_width(int_node._index_width),
      _value_width(int_node._value_width) { } 

    // Copying assign operator.  Also copies contents of children.
    ASTInternal& operator=(const ASTInternal &int_node);

    // Cleanup function for removing from hash table
    virtual void CleanUp() = 0;

    // Destructor (does nothing, but is declared virtual here.
    virtual ~ASTInternal();

    // Abstract virtual print function for internal node.
    virtual void nodeprint(ostream& os) { os << "*"; };
  }; //End of Class ASTInternal

  // FIXME: Should children be only in interior node type?
  /***************************************************************************
    Class ASTInterior: Internal representation of an interior
       ASTNode.  Generally, these nodes should have at least one
      child
  ***************************************************************************/
  class ASTInterior : public ASTInternal {    

    friend class BeevMgr;
    friend class ASTNodeHasher;
    friend class ASTNodeEqual;   

  private:

    // Hasher for ASTInterior pointer nodes
    class ASTInteriorHasher {
    public:
      size_t operator()(const ASTInterior *int_node_ptr) const;
    };

    // Equality for ASTInterior nodes
    class ASTInteriorEqual {
    public:
      bool operator()(const ASTInterior *int_node_ptr1, 
		      const ASTInterior *int_node_ptr2) const{
	return (*int_node_ptr1 == *int_node_ptr2);
      }
    };

    // Used in Equality class for hash tables
    friend bool operator==(const ASTInterior &int_node1, 
			   const ASTInterior &int_node2){
      return (int_node1._kind == int_node2._kind) && 
	(int_node1._children == int_node2._children);
    }

    // Call this when deleting a node that has been stored in the
    // the unique table
    virtual void CleanUp();

    // Returns kinds.  "lispprinter" handles printing of parenthesis
    // and childnodes.
    virtual void nodeprint(ostream& os) {
      os << _kind_names[_kind];
    }
    public:

    // FIXME: This should not be public, but has to be because the
    // ASTInterior hash table insists on it.  I can't seem to make the
    // private destructor visible to hash_set.  It does not even work
    // to put "friend class hash_set<ASTInterior, ...>" in here.

    // Basic constructors
    ASTInterior(Kind kind,  BeevMgr &bm) :
      ASTInternal(kind, bm) {  }    

    ASTInterior(Kind kind, ASTVec &children, BeevMgr &bm) :
      ASTInternal(kind, children, bm) {  }    

    //Copy constructor.  This copies the contents of the child nodes
    //array, along with everything else. Assigning the smart pointer,
    //ASTNode, does NOT invoke this.
    ASTInterior(const ASTInterior &int_node) : ASTInternal(int_node) { }

    // Destructor (does nothing, but is declared virtual here.
    virtual ~ASTInterior();

  }; //End of ASTNodeInterior


  /***************************************************************************/
  /*  Class ASTSymbol:  Class to represent internals of Symbol node.         */
  /***************************************************************************/
  class ASTSymbol : public ASTInternal{
    friend class BeevMgr;
    friend class ASTNode;
    friend class ASTNodeHasher;
    friend class ASTNodeEqual;

  private:
    // The name of the symbol
    const char * const _name;
    
    class ASTSymbolHasher{
    public:
      size_t operator() (const ASTSymbol *sym_ptr) const{ 
	hash<char*> h; 
	return h(sym_ptr->_name); 
      };
    };

    // Equality for ASTInternal nodes
    class ASTSymbolEqual{
    public:
      bool operator()(const ASTSymbol *sym_ptr1, const ASTSymbol *sym_ptr2) const{ 
	return (*sym_ptr1 == *sym_ptr2); 
      }
    };

    friend bool operator==(const ASTSymbol &sym1, const ASTSymbol &sym2){
      return (strcmp(sym1._name, sym2._name) == 0);
    }

    const char *GetName() const{return _name;}  

    // Print function for symbol -- return name */
    virtual void nodeprint(ostream& os) { os << _name;}

    // Call this when deleting a node that has been stored in the
    // the unique table
    virtual void CleanUp();

    public:

    // Default constructor
    ASTSymbol(BeevMgr &bm) : ASTInternal(bm), _name(NULL) { }

    // Constructor.  This does NOT copy its argument.
    ASTSymbol(const char * const name, BeevMgr &bm) : ASTInternal(SYMBOL, bm), 
						      _name(name) { }
    
    // Destructor (does nothing, but is declared virtual here.
    virtual ~ASTSymbol();
    
    // Copy constructor
    // FIXME: seems to be calling default constructor for astinternal
    ASTSymbol(const ASTSymbol &sym) :
      ASTInternal(sym._kind, sym._children, sym._bm), 
      _name(sym._name) { } 
  }; //End of ASTSymbol
  

  /***************************************************************************/
  /*  Class ASTBVConst:  Class to represent internals of a bitvectorconst    */
  /***************************************************************************/

#ifndef NATIVE_C_ARITH

  class ASTBVConst : public ASTInternal {
    friend class BeevMgr;
    friend class ASTNode;
    friend class ASTNodeHasher;
    friend class ASTNodeEqual;
    
  private:
    //This is the private copy of a bvconst currently
    //This should not be changed at any point
    CBV _bvconst;

    class ASTBVConstHasher{
    public:
      size_t operator() (const ASTBVConst * bvc) const {
        return CONSTANTBV::BitVector_Hash(bvc->_bvconst);
      };
    };

    class ASTBVConstEqual{
    public:
      bool operator()(const ASTBVConst * bvc1, const ASTBVConst  * bvc2) const { 
        if( bvc1->_value_width != bvc2->_value_width){
	  return false;
	}  
	return (0==CONSTANTBV::BitVector_Compare(bvc1->_bvconst,bvc2->_bvconst));
      }
    };
    
    //FIXME Keep an eye on this function
    ASTBVConst(CBV bv, unsigned int width, BeevMgr &bm) :
      ASTInternal(BVCONST, bm)
    {
      _bvconst = CONSTANTBV::BitVector_Clone(bv);
      _value_width = width;
    }

    friend bool operator==(const ASTBVConst &bvc1, const ASTBVConst &bvc2){
      if(bvc1._value_width != bvc2._value_width)
        return false;
      return (0==CONSTANTBV::BitVector_Compare(bvc1._bvconst,bvc2._bvconst));
    }
    // Call this when deleting a node that has been stored in the
    // the unique table
    virtual void CleanUp();

    // Print function for bvconst -- return _bvconst value in bin format
    virtual void nodeprint(ostream& os) {
      unsigned char *res;
      const char *prefix;

      if (_value_width%4 == 0) {
        res = CONSTANTBV::BitVector_to_Hex(_bvconst);
        prefix = "0hex";
      } else {      
        res = CONSTANTBV::BitVector_to_Bin(_bvconst);
        prefix = "0bin";
      }
      if (NULL == res) {
        os << "nodeprint: BVCONST : could not convert to string" << _bvconst;
        FatalError("");
      }
      os << prefix << res;
      CONSTANTBV::BitVector_Dispose(res);
    }

    // Copy constructor.     
    ASTBVConst(const ASTBVConst &sym) : 
      ASTInternal(sym._kind, sym._children, sym._bm)
    {
      _bvconst = CONSTANTBV::BitVector_Clone(sym._bvconst);
      _value_width = sym._value_width;
    }
    
  public:
    virtual ~ASTBVConst(){
       CONSTANTBV::BitVector_Destroy(_bvconst);
    }

    CBV GetBVConst() const {return _bvconst;}
  }; //End of ASTBVConst

  //FIXME This function is DEPRICATED
  //Do not use in the future
  inline unsigned int GetUnsignedConst(const ASTNode n) {
    if(32 < n.GetValueWidth())
      FatalError("GetUnsignedConst: cannot convert bvconst of length greater than 32 to unsigned int:");
        
    return (unsigned int) *((unsigned int *)n.GetBVConst());
  }
#else
  class ASTBVConst : public ASTInternal {
    friend class BeevMgr;
    friend class ASTNode;
    friend class ASTNodeHasher;
    friend class ASTNodeEqual;

  private:
    // the bitvector contents. bitvector contents will be in two
    // modes. one mode where all bitvectors are NATIVE and in this
    // mode we use native unsigned long long int to represent the
    // 32/64 bitvectors. The other for arbitrary length bitvector
    // operations.
    const unsigned long long int _bvconst;

    class ASTBVConstHasher{
    public:
      size_t operator() (const ASTBVConst * bvc) const{ 
	//Thomas Wang's 64 bit Mix Function
	unsigned long long int key(bvc->_bvconst);
	key += ~(key << 32);
	key ^= (key  >> 22);
	key += ~(key << 13);
	key ^= (key  >> 8);
	key += (key  << 3);
	key ^= (key  >> 15);
	key += ~(key << 27);
	key ^= (key  >> 31);
	
	size_t return_key = key;
	return return_key;
      };
    };

    class ASTBVConstEqual{
    public:
      bool operator()(const ASTBVConst * bvc1, const ASTBVConst  * bvc2) const { 
	return ((bvc1->_bvconst == bvc2->_bvconst) 
		&& (bvc1->_value_width == bvc2->_value_width));
      }
    };

    // Call this when deleting a node that has been stored in the
    // the unique table
    virtual void CleanUp();
  public:
    // Default constructor
    ASTBVConst(const unsigned long long int bv, BeevMgr &bm) : 
      ASTInternal(BVCONST, bm), _bvconst(bv) { 
    }

    // Copy constructor. FIXME: figure out how this is supposed to
    // work.
    ASTBVConst(const ASTBVConst &sym) : 
      ASTInternal(sym._kind, sym._children, sym._bm), 
      _bvconst(sym._bvconst) { 
      _value_width = sym._value_width;
    } 

    // Destructor (does nothing, but is declared virtual here)
    virtual ~ASTBVConst() { } 
    
    friend bool operator==(const ASTBVConst &sym1, const ASTBVConst &sym2){
      return ((sym1._bvconst == sym2._bvconst) && 
	      (sym1._value_width == sym2._value_width));
    }

    // Print function for bvconst -- return _bvconst value in binary format
    virtual void nodeprint(ostream& os) {
      string s = "0bin";
      unsigned long long int bitmask = 0x8000000000000000LL;
      bitmask = bitmask >> (64-_value_width);

      for (; bitmask > 0; bitmask >>= 1)
	s += (_bvconst & bitmask) ? '1' : '0';	
      os << s;
    }
    
    unsigned long long int GetBVConst() const  {return _bvconst;}
  }; //End of ASTBVConst

  //return value of bvconst
  inline unsigned int GetUnsignedConst(const ASTNode n) {
    if(32 < n.GetValueWidth())
      FatalError("GetUnsignedConst: cannot convert bvconst of length greater than 32 to unsigned int:");    
    return (unsigned int)n.GetBVConst();
  }
#endif
/*
#else
  // the bitvector contents. bitvector contents will be in two
  // modes. one mode where all bitvectors are NATIVE and in this mode
  // we use native unsigned long long int to represent the 32/64
  // bitvectors. The other for arbitrary length bitvector operations.

  //BVCONST defined for arbitrary length bitvectors
  class ASTBVConst : public ASTInternal{
    friend class BeevMgr;
    friend class ASTNode;
    friend class ASTNodeHasher;
    friend class ASTNodeEqual;

  private:
    const char * const _bvconst;

    class ASTBVConstHasher{
    public:
      size_t operator() (const ASTBVConst * bvc) const{ 
	hash<char*> h;	
	return h(bvc->_bvconst);
      };
    };

    class ASTBVConstEqual{
    public:
      bool operator()(const ASTBVConst * bvc1, const ASTBVConst  * bvc2) const { 
	if(bvc1->_value_width != bvc2->_value_width)
	  return false;
	return (0 == strncmp(bvc1->_bvconst,bvc2->_bvconst,bvc1->_value_width));
      }
    };
    
    ASTBVConst(const char * bv, BeevMgr &bm) : 
      ASTInternal(BVCONST, bm), _bvconst(bv) { 
      //_value_width = strlen(bv);
    }

    friend bool operator==(const ASTBVConst &bvc1, const ASTBVConst &bvc2){
      if(bvc1._value_width != bvc2._value_width)
	return false;
      return (0 == strncmp(bvc1._bvconst,bvc2._bvconst,bvc1._value_width));
    }

    // Call this when deleting a node that has been stored in the
    // the unique table
    virtual void CleanUp();

    // Print function for bvconst -- return _bvconst value in binary format
    virtual void nodeprint(ostream& os) {
      if(_value_width%4 == 0) {
	unsigned int *  iii = CONSTANTBV::BitVector_Create(_value_width,true);
	CONSTANTBV::ErrCode e = CONSTANTBV::BitVector_from_Bin(iii,(unsigned char*)_bvconst);
	//error printing
	if(0 != e) {
	  os << "nodeprint: BVCONST : wrong hex value: " << BitVector_Error(e);
	  FatalError("");
	}
	unsigned char * ccc = CONSTANTBV::BitVector_to_Hex(iii);
	os << "0hex" << ccc;
	CONSTANTBV::BitVector_Destroy(iii);
      }
      else {
	std::string s(_bvconst,_value_width);
	s = "0bin" + s;
	os << s;
      }
    }

    // Copy constructor.     
    ASTBVConst(const ASTBVConst &sym) : ASTInternal(sym._kind, sym._children, sym._bm),_bvconst(sym._bvconst) { 
      //checking if the input is in the correct format
      for(unsigned int jj=0;jj<sym._value_width;jj++)
	if(!(sym._bvconst[jj] == '0' || sym._bvconst[jj] == '1')) {
	  cerr << "Fatal Error: wrong input to ASTBVConst copy constructor:" << sym._bvconst << endl;
	  FatalError("");
	}
      _value_width = sym._value_width;
    } 
  public:
    // Destructor (does nothing, but is declared virtual here)
    virtual ~ASTBVConst(){}

    const char * const GetBVConst() const {return _bvconst;}
  }; //End of ASTBVConst

  unsigned int * ConvertToCONSTANTBV(const char * s);

  //return value of bvconst
  inline unsigned int GetUnsignedConst(const ASTNode n) {
    if(32 < n.GetValueWidth())
      FatalError("GetUnsignedConst: cannot convert bvconst of length greater than 32 to unsigned int:");    
    std::string s(n.GetBVConst(), n.GetValueWidth());
      unsigned int output = strtoul(s.c_str(),NULL,2);
      return output;
  } //end of ASTBVConst class
#endif
*/
  /***************************************************************************
   * Typedef ASTNodeMap:  This is a hash table from ASTNodes to ASTNodes.
   * It is very convenient for attributes that are not speed-critical
   **************************************************************************/
  // These are generally useful for storing ASTNodes or attributes thereof
  // Hash table from ASTNodes to ASTNodes
  typedef hash_map<ASTNode, ASTNode, 
		   ASTNode::ASTNodeHasher, 
		   ASTNode::ASTNodeEqual> ASTNodeMap;

  // Function to dump contents of ASTNodeMap
  ostream &operator<<(ostream &os, const ASTNodeMap &nmap);
  
  /***************************************************************************
   Typedef ASTNodeSet:  This is a hash set of ASTNodes.  Very useful
   for representing things like "visited nodes"
  ***************************************************************************/
  typedef hash_set<ASTNode, 
		   ASTNode::ASTNodeHasher, 
		   ASTNode::ASTNodeEqual> ASTNodeSet;

  typedef hash_multiset<ASTNode, 
			ASTNode::ASTNodeHasher, 
			ASTNode::ASTNodeEqual> ASTNodeMultiSet;

  //external parser table for declared symbols.
  //FIXME: move to a more appropriate place
  extern ASTNodeSet _parser_symbol_table;
  
  /***************************************************************************
    Class LispPrinter:  iomanipulator for printing ASTNode or ASTVec       
  ***************************************************************************/
  class LispPrinter {

  public:
    ASTNode _node;

    // number of spaces to print before first real character of
    // object.
    int _indentation;  

    // FIXME: pass ASTNode by reference
    // Constructor to build the LispPrinter object
    LispPrinter(ASTNode node, int indentation): _node(node), _indentation(indentation) { }    

    friend ostream &operator<<(ostream &os, const LispPrinter &lp){ 
      return lp._node.LispPrint(os, lp._indentation); 
    };

  }; //End of ListPrinter
  
  //This is the IO manipulator.  It builds an object of class
  //"LispPrinter" that has a special overloaded "<<" operator.
  inline LispPrinter lisp(const ASTNode &node, int indentation = 0){
    LispPrinter lp(node, indentation);
    return lp;
  }
  
  /***************************************************************************/
  /*  Class LispVecPrinter:iomanipulator for printing vector of ASTNodes     */
  /***************************************************************************/
  class LispVecPrinter {

  public:
    const ASTVec * _vec;
    // number of spaces to print before first real
    // character of object.    
    int _indentation;
    
    // Constructor to build the LispPrinter object
    LispVecPrinter(const ASTVec &vec, int indentation){
      _vec = &vec; _indentation = indentation; 
    }
    
    friend ostream &operator<<(ostream &os, const LispVecPrinter &lvp){
    LispPrintVec(os, *lvp._vec, lvp._indentation);
    return os;
    };
  }; //End of Class ListVecPrinter

  //iomanipulator. builds an object of class "LisPrinter" that has a
  //special overloaded "<<" operator.
  inline LispVecPrinter lisp(const ASTVec &vec, int indentation = 0){
    LispVecPrinter lvp(vec, indentation);
    return lvp;
  }


  /*****************************************************************
   * INLINE METHODS from various classed, declared here because of
   * dependencies on classes that are declared later.
   *****************************************************************/
  // ASTNode accessor function.
  inline Kind ASTNode::GetKind() const { 
    //cout << "GetKind: " << _int_node_ptr; 
    return _int_node_ptr->GetKind(); 
  }

  // FIXME: should be const ASTVec const?  
  // Declared here because of same ordering problem as  GetKind.
  inline const ASTVec &ASTNode::GetChildren() const { 
    return _int_node_ptr->GetChildren(); 
  }

  // Access node number
  inline int ASTNode::GetNodeNum() const { 
    return _int_node_ptr->_node_num; 
  }

  inline unsigned int ASTNode::GetIndexWidth () const { 
    return _int_node_ptr->_index_width; 
  }
  
  inline void ASTNode::SetIndexWidth (unsigned int iw) const { 
    _int_node_ptr->_index_width = iw;
  }
  
  inline unsigned int ASTNode::GetValueWidth () const { 
    return _int_node_ptr->_value_width; 
  }
  
  inline void ASTNode::SetValueWidth (unsigned int vw) const {
    _int_node_ptr->_value_width = vw; 
  }

  //return the type of the ASTNode: 0 iff BOOLEAN; 1 iff BITVECTOR; 2
  //iff ARRAY; 3 iff UNKNOWN;
  inline types ASTNode::GetType() const {
    if((GetIndexWidth() == 0) && (GetValueWidth() == 0)) //BOOLEAN
      return BOOLEAN_TYPE;
    if((GetIndexWidth() == 0) && (GetValueWidth() > 0))  //BITVECTOR
      return BITVECTOR_TYPE;
    if((GetIndexWidth() > 0) && (GetValueWidth() > 0)) //ARRAY
      return ARRAY_TYPE;
    return UNKNOWN_TYPE; 
  }

  // Constructor; creates a new pointer, increments refcount of
  // pointed-to object.
#ifndef SMTLIB
  inline ASTNode::ASTNode(ASTInternal *in) : _int_node_ptr(in) { 
    if (in) in->IncRef(); 
  }
#else
  inline ASTNode::ASTNode(ASTInternal *in) : _int_node_ptr(in) { };
#endif

  // Assignment.  Increment refcount of new value, decrement refcount
  // of old value and destroy if this was the last pointer.  FIXME:
  // accelerate this by creating an intnode with a ref counter instead
  // of pointing to NULL.  Need a special check in CleanUp to make
  // sure the null node never gets freed.

#ifndef SMTLIB
  inline ASTNode& ASTNode::operator=(const ASTNode& n) {
    if (n._int_node_ptr) {
      n._int_node_ptr->IncRef();
    }
    if (_int_node_ptr) {
      _int_node_ptr->DecRef();
    }
    _int_node_ptr = n._int_node_ptr;
    return *this;
  }
#else
  inline ASTNode& ASTNode::operator=(const ASTNode& n) {
    _int_node_ptr = n._int_node_ptr;
    return *this;
  }
#endif

#ifndef SMTLIB
  inline void ASTInternal::DecRef()
  {
    if (--_ref_count == 0) {
      // Delete node from unique table and kill it.
      CleanUp();
    }
  }

  // Destructor
  inline ASTNode::~ASTNode()
  {
    if (_int_node_ptr) {
      _int_node_ptr->DecRef();
    }
  }
#else
  // No refcounting
  inline void ASTInternal::DecRef()
  {
  }

  // Destructor
  inline ASTNode::~ASTNode()
  {
  };
#endif

  inline BeevMgr& ASTNode::GetBeevMgr() const { return _int_node_ptr->_bm; }

  /***************************************************************************
   * Class BeevMgr.  This holds all "global" variables for the system, such as
   * unique tables for the various kinds of nodes.
   ***************************************************************************/
  class BeevMgr {
    friend class ASTNode;	// ASTNode modifies AlreadyPrintedSet
				// in BeevMgr
    friend class ASTInterior;
    friend class ASTBVConst;
    friend class ASTSymbol;

    // FIXME: The values appear to be the same regardless of the value of SMTLIB
    // initial hash table sizes, to save time on resizing.
#ifdef SMTLIB
    static const int INITIAL_INTERIOR_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_SYMBOL_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_BVCONST_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_BBTERM_MEMO_TABLE_SIZE = 100;
    static const int INITIAL_BBFORM_MEMO_TABLE_SIZE = 100;

    static const int INITIAL_SIMPLIFY_MAP_SIZE = 100;
    static const int INITIAL_SOLVER_MAP_SIZE = 100;
    static const int INITIAL_ARRAYREAD_SYMBOL_SIZE = 100;
    static const int INITIAL_INTRODUCED_SYMBOLS_SIZE = 100;
#else
    // these are the STL defaults
    static const int INITIAL_INTERIOR_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_SYMBOL_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_BVCONST_UNIQUE_TABLE_SIZE = 100;
    static const int INITIAL_BBTERM_MEMO_TABLE_SIZE = 100;
    static const int INITIAL_BBFORM_MEMO_TABLE_SIZE = 100;

    static const int INITIAL_SIMPLIFY_MAP_SIZE = 100;
    static const int INITIAL_SOLVER_MAP_SIZE = 100;
    static const int INITIAL_ARRAYREAD_SYMBOL_SIZE = 100;
    static const int INITIAL_INTRODUCED_SYMBOLS_SIZE = 100;
#endif

  private:
    // Typedef for unique Interior node table. 
    typedef hash_set<ASTInterior *, 
		     ASTInterior::ASTInteriorHasher, 
		     ASTInterior::ASTInteriorEqual> ASTInteriorSet;

    // Typedef for unique Symbol node (leaf) table.
    typedef hash_set<ASTSymbol *, 
		     ASTSymbol::ASTSymbolHasher, 
		     ASTSymbol::ASTSymbolEqual> ASTSymbolSet;

    // Unique tables to share nodes whenever possible.
    ASTInteriorSet _interior_unique_table;
    //The _symbol_unique_table is also the symbol table to be used
    //during parsing/semantic analysis
    ASTSymbolSet _symbol_unique_table;
    
    //Typedef for unique BVConst node (leaf) table.
    typedef hash_set<ASTBVConst *, 
		     ASTBVConst::ASTBVConstHasher,
		     ASTBVConst::ASTBVConstEqual> ASTBVConstSet;

    //table to uniquefy bvconst
    ASTBVConstSet _bvconst_unique_table;

    // type of memo table.
    typedef hash_map<ASTNode, ASTVec,
		     ASTNode::ASTNodeHasher, 
		     ASTNode::ASTNodeEqual> ASTNodeToVecMap;

    typedef hash_map<ASTNode,ASTNodeSet,
		     ASTNode::ASTNodeHasher,
		     ASTNode::ASTNodeEqual> ASTNodeToSetMap;
    
    // Memo table for bit blasted terms.  If a node has already been
    // bitblasted, it is mapped to a vector of Boolean formulas for
    // the bits.
    
    //OLD: ASTNodeToVecMap BBTermMemo;
    ASTNodeMap BBTermMemo;
    
    // Memo table for bit blasted formulas.  If a node has already
    // been bitblasted, it is mapped to a node representing the
    // bitblasted equivalent
    ASTNodeMap BBFormMemo;
    
    //public:
    // Get vector of Boolean formulas for sum of two
    // vectors of Boolean formulas
    void BBPlus2(ASTVec& sum, const ASTVec& y, ASTNode cin);
    // Increment
    ASTVec BBInc(ASTVec& x);
    // Add one bit to a vector of bits.
    ASTVec BBAddOneBit(ASTVec& x, ASTNode cin);
    // Bitwise complement
    ASTVec BBNeg(const ASTVec& x);
    // Unary minus
    ASTVec BBUminus(const ASTVec& x);
    // Multiply.
    ASTVec BBMult(const ASTVec& x, const ASTVec& y);
    // AND each bit of vector y with single bit b and return the result.
    // (used in BBMult)
    ASTVec BBAndBit(const ASTVec& y, ASTNode b);
    // Returns ASTVec for result - y.  This destroys "result".
    void BBSub(ASTVec& result, const ASTVec& y);
    // build ITE's (ITE cond then[i] else[i]) for each i.
    ASTVec BBITE(const ASTNode& cond, 
		 const ASTVec& thn, const ASTVec& els);
    // Build a vector of zeros.
    ASTVec BBfill(unsigned int width, ASTNode fillval);
    // build an EQ formula
    ASTNode BBEQ(const ASTVec& left, const ASTVec& right);

    // This implements a variant of binary long division.
    // q and r are "out" parameters.  rwidth puts a bound on the
    // recursion depth.   Unsigned only, for now.
    void BBDivMod(const ASTVec &y,
		  const ASTVec &x,
		  ASTVec &q,
		  ASTVec &r,
		  unsigned int rwidth);
    
    // Return formula for majority function of three formulas.
    ASTNode Majority(const ASTNode& a, const ASTNode& b, const ASTNode& c);

    // Internal bit blasting routines.
    ASTNode BBBVLE(const ASTVec& x, const ASTVec& y, bool is_signed);

    // Return bit-blasted form for BVLE, BVGE, BVGT, SBLE, etc. 
    ASTNode BBcompare(const ASTNode& form);

    // Left and right shift one.  Writes into x.
    void BBLShift(ASTVec& x);
    void BBRShift(ASTVec& x);

  public:
    // Simplifying create functions
    ASTNode CreateSimpForm(Kind kind, ASTVec &children);
    ASTNode CreateSimpForm(Kind kind, const ASTNode& child0);
    ASTNode CreateSimpForm(Kind kind,
				    const ASTNode& child0,
				    const ASTNode& child1);
    ASTNode CreateSimpForm(Kind kind,
				    const ASTNode& child0,
				    const ASTNode& child1,
				    const ASTNode& child2);

    ASTNode CreateSimpNot(const ASTNode& form);

    // These are for internal use only.
    // FIXME: Find a way to make this local to SimpBool, so they're
    // not in AST.h
    ASTNode CreateSimpXor(const ASTNode& form1,
			  const ASTNode& form2);
    ASTNode CreateSimpXor(ASTVec &children);
    ASTNode CreateSimpAndOr(bool isAnd,
				     const ASTNode& form1,
				     const ASTNode& form2);
    ASTNode CreateSimpAndOr(bool IsAnd, ASTVec &children);
    ASTNode CreateSimpFormITE(const ASTNode& child0,
				       const ASTNode& child1,
				       const ASTNode& child2);
    

    // Declarations of BitBlaster functions (BitBlast.cpp)
  public:
    // Adds or removes a NOT as necessary to negate a literal.
    ASTNode Negate(const ASTNode& form);

    // Bit blast a bitvector term.  The term must have a kind for a
    // bitvector term.  Result is a ref to a vector of formula nodes
    // representing the boolean formula.
    const ASTNode BBTerm(const ASTNode& term);

    const ASTNode BBForm(const ASTNode& formula);

    // Declarations of CNF conversion (ToCNF.cpp)
  public:
    // ToCNF converts a bit-blasted Boolean formula to Conjunctive
    // 	Normal Form, suitable for many SAT solvers.  Our CNF representation
    // 	is an STL vector of STL vectors, for independence from any particular
    // 	SAT solver's representation.  There needs to be a separate driver to
    // 	convert our clauselist to the representation used by the SAT solver.    
    // 	Currently, there is only one such solver and its driver is "ToSAT"
    
    // Datatype for clauses
    typedef ASTVec * ClausePtr;
    
    // Datatype for Clauselists
    typedef vector<ClausePtr> ClauseList;

    // Convert a Boolean formula to an equisatisfiable CNF formula.
    ClauseList *ToCNF(const ASTNode& form);

    // Print function for debugging
    void PrintClauseList(ostream& os, ClauseList& cll); 

    // Free the clause list and all its clauses.
    void DeleteClauseList(BeevMgr::ClauseList *cllp);

    // Map from formulas to representative literals, for debugging.
    ASTNodeMap RepLitMap;

  private:
    // Global for assigning new node numbers.
    int _max_node_num;
    
    const ASTNode ASTFalse, ASTTrue, ASTUndefined;
    
    // I just did this so I could put it in as a fake return value in
    // methods that return a ASTNode &, to make -Wall shut up.
    ASTNode dummy_node;

    //BeevMgr Constructor, Destructor and other misc. functions
  public:

    int NewNodeNum() { _max_node_num += 2; return _max_node_num; } 
    
    // Table for DAG printing.
    ASTNodeSet AlreadyPrintedSet;

    //Tables for Presentation language printing

    //Nodes seen so far
    ASTNodeSet PLPrintNodeSet;

    //Map from ASTNodes to LetVars
    ASTNodeMap NodeLetVarMap;
    
    //This is a vector which stores the Node to LetVars pairs. It
    //allows for sorted printing, as opposed to NodeLetVarMap
    std::vector<pair<ASTNode,ASTNode> > NodeLetVarVec;

    //a partial Map from ASTNodes to LetVars. Needed in order to
    //correctly print shared subterms inside the LET itself
    ASTNodeMap NodeLetVarMap1;

    //functions to lookup nodes from the memo tables. these should be
    //private.
  private:
    //Destructively appends back_child nodes to front_child nodes.
    //If back_child nodes is NULL, no appending is done.  back_child
    //nodes are not modified.  Then it returns the hashed copy of the
    //node, which is created if necessary.
    ASTInterior *CreateInteriorNode(Kind kind,
				    ASTInterior *new_node,
				    // this is destructively modified.
				    const ASTVec & back_children = _empty_ASTVec);

    // Create unique ASTInterior node.
    ASTInterior *LookupOrCreateInterior(ASTInterior *n);

    // Create unique ASTSymbol node. 
    ASTSymbol *LookupOrCreateSymbol(ASTSymbol& s);
    
    // Called whenever we want to make sure that the Symbol is
    // declared during semantic analysis
    bool LookupSymbol(ASTSymbol& s);
      
    // Called by ASTNode constructors to uniqueify ASTBVConst
    ASTBVConst *LookupOrCreateBVConst(ASTBVConst& s);

    //Public functions for CreateNodes and Createterms
  public:
    // Create and return an ASTNode for a symbol
    ASTNode CreateSymbol(const char * const name);

    // Create and return an ASTNode for a symbol
    // Width is number of bits.
    ASTNode CreateBVConst(unsigned int width, unsigned long long int bvconst);
    ASTNode CreateZeroConst(unsigned int width);
    ASTNode CreateOneConst(unsigned int width);
    ASTNode CreateTwoConst(unsigned int width);
    ASTNode CreateMaxConst(unsigned int width);

    // Create and return an ASTNode for a symbol
    // Optional base was a problem because 0 could be an int or char *,
    // so CreateBVConst was ambiguous.
    ASTNode CreateBVConst(const char *strval, int base);

    //FIXME This is a dangerous function 
    ASTNode CreateBVConst(CBV bv, unsigned width);

    // Create and return an interior ASTNode
    ASTNode CreateNode(Kind kind, const ASTVec &children = _empty_ASTVec);

    ASTNode CreateNode(Kind kind,
		       const ASTNode& child0,
		       const ASTVec &children = _empty_ASTVec);

    ASTNode CreateNode(Kind kind,
		       const ASTNode& child0,
		       const ASTNode& child1,
		       const ASTVec &children = _empty_ASTVec);    

    ASTNode CreateNode(Kind kind,
		       const ASTNode& child0,
		       const ASTNode& child1,
		       const ASTNode& child2,
		       const ASTVec &children = _empty_ASTVec);

    // Create and return an ASTNode for a term
    inline ASTNode CreateTerm(Kind kind, 
		       unsigned int width, 
		       const ASTVec &children = _empty_ASTVec) {
      if(!is_Term_kind(kind))
	FatalError("CreateTerm:  Illegal kind to CreateTerm:",ASTUndefined, kind);
      ASTNode n = CreateNode(kind, children);
      n.SetValueWidth(width);

      //by default we assume that the term is a Bitvector. If
      //necessary the indexwidth can be changed later
      n.SetIndexWidth(0);
      return n;
    }

    inline ASTNode CreateTerm(Kind kind,
		       unsigned int width,
		       const ASTNode& child0,
		       const ASTVec &children = _empty_ASTVec) {
      if(!is_Term_kind(kind))
	FatalError("CreateTerm:  Illegal kind to CreateTerm:",ASTUndefined, kind);
      ASTNode n = CreateNode(kind, child0, children);
      n.SetValueWidth(width);
      return n;
    }
     
    inline ASTNode CreateTerm(Kind kind,
		       unsigned int width,
		       const ASTNode& child0,
		       const ASTNode& child1,
		       const ASTVec &children = _empty_ASTVec) {
      if(!is_Term_kind(kind))
	FatalError("CreateTerm:  Illegal kind to CreateTerm:",ASTUndefined, kind);
      ASTNode n = CreateNode(kind, child0, child1, children);
      n.SetValueWidth(width);
      return n;
    }

    inline ASTNode CreateTerm(Kind kind,
		       unsigned int width,
		       const ASTNode& child0,
		       const ASTNode& child1,
		       const ASTNode& child2,
		       const ASTVec &children = _empty_ASTVec) {
      if(!is_Term_kind(kind))
	FatalError("CreateTerm:  Illegal kind to CreateTerm:",ASTUndefined, kind);
      ASTNode n = CreateNode(kind, child0, child1, child2, children);
      n.SetValueWidth(width);
      return n;
    }

    ASTNode SimplifyFormula_NoRemoveWrites(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyFormula_TopLevel(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyTerm_TopLevel(const ASTNode& b);
    ASTNode SimplifyTerm(const ASTNode& a);
    void CheckSimplifyInvariant(const ASTNode& a, const ASTNode& output);    
  private:
    //memo table for simplifcation
    ASTNodeMap SimplifyMap;
    ASTNodeMap SimplifyNegMap;
    ASTNodeMap SolverMap;
    ASTNodeSet AlwaysTrueFormMap;
    ASTNodeMap MultInverseMap;

  public:
    ASTNode SimplifyAtomicFormula(const ASTNode& a, bool pushNeg);
    ASTNode CreateSimplifiedEQ(const ASTNode& t1, const ASTNode& t2);
    ASTNode ITEOpt_InEqs(const ASTNode& in1);
    ASTNode CreateSimplifiedTermITE(const ASTNode& t1, const ASTNode& t2, const ASTNode& t3);
    ASTNode CreateSimplifiedINEQ(Kind k, const ASTNode& a0, const ASTNode& a1, bool pushNeg);
    ASTNode SimplifyNotFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyAndOrFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyXorFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyNandFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyNorFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyImpliesFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyIffFormula(const ASTNode& a, bool pushNeg);
    ASTNode SimplifyIteFormula(const ASTNode& a, bool pushNeg);
    ASTNode FlattenOneLevel(const ASTNode& a);
    ASTNode FlattenAndOr(const ASTNode& a);
    ASTNode CombineLikeTerms(const ASTNode& a);
    ASTNode LhsMinusRhs(const ASTNode& eq);
    ASTNode DistributeMultOverPlus(const ASTNode& a, 
				   bool startdistribution=false);
    ASTNode ConvertBVSXToITE(const ASTNode& a);
    //checks if the input constant is odd or not
    bool BVConstIsOdd(const ASTNode& c);
    //computes the multiplicatve inverse of the input
    ASTNode MultiplicativeInverse(const ASTNode& c);
 
    void ClearAllTables(void);
    void ClearAllCaches(void);
    int  BeforeSAT_ResultCheck(const ASTNode& q);
    int  CallSAT_ResultCheck(MINISAT::Solver& newS, 
			     const ASTNode& q, const ASTNode& orig_input);   
    int  SATBased_ArrayReadRefinement(MINISAT::Solver& newS, 
				      const ASTNode& q, const ASTNode& orig_input);
    int SATBased_ArrayWriteRefinement(MINISAT::Solver& newS, const ASTNode& orig_input);
    //creates array write axiom only for the input term or formula, if
    //necessary. If there are no axioms to produce then it simply
    //generates TRUE
    ASTNode Create_ArrayWriteAxioms(const ASTNode& array_readoverwrite_term, const ASTNode& array_newname);
    ASTVec ArrayWrite_RemainingAxioms;
    //variable indicates that counterexample will now be checked by
    //the counterexample checker, and hence simplifyterm must switch
    //off certain optimizations. In particular, array write
    //optimizations
    bool start_abstracting;
    bool Begin_RemoveWrites;
    bool SimplifyWrites_InPlace_Flag;

    void CopySolverMap_To_CounterExample(void);
    //int LinearSearch(const ASTNode& orig_input);    
    //Datastructures and functions needed for counterexample
    //generation, and interface with MINISAT
  private:
    /* MAP: This is a map from ASTNodes to MINISAT::Vars. 
     *
     * The map is populated while ASTclauses are read from the AST
     * ClauseList returned by CNF converter. For every new boolean
     * variable in ASTClause a new MINISAT::Var is created (these vars
     * typedefs for ints)
     */
    typedef hash_map<ASTNode, MINISAT::Var, 
		     ASTNode::ASTNodeHasher, 
		     ASTNode::ASTNodeEqual> ASTtoSATMap;        
    ASTtoSATMap _ASTNode_to_SATVar;

  public:  
    //converts the clause to SAT and calls SAT solver
    bool toSATandSolve(MINISAT::Solver& S, ClauseList& cll);

    ///print SAT solver statistics
    void PrintStats(MINISAT::SolverStats& stats);

    //accepts query and returns the answer. if query is valid, return
    //true, else return false. Automatically constructs counterexample
    //for invalid queries, and prints them upon request.
    int TopLevelSAT(const ASTNode& query, const ASTNode& asserts);

    // Debugging function to find problems in BitBlast and ToCNF.
    // See body in ToSAT.cpp for more explanation.
    ASTNode CheckBBandCNF(MINISAT::Solver& newS, ASTNode form);

    // Internal recursive body of above.
    ASTNode CheckBBandCNF_int(MINISAT::Solver& newS, ASTNode form);

    // Helper function for CheckBBandCNF
    ASTNode SymbolTruthValue(MINISAT::Solver &newS, ASTNode form); 

    //looksup a MINISAT var from the minisat-var memo-table. if none
    //exists, then creates one.
    MINISAT::Var LookupOrCreateSATVar(MINISAT::Solver& S, const ASTNode& n);

    // Memo table for CheckBBandCNF debugging function
    ASTNodeMap CheckBBandCNFMemo;


    //Data structures for Array Read Transformations
  private:
    /* MAP: This is a map from Array Names to list of array-read
     * indices in the input. This map is used by the TransformArray()
     * function
     *
     * This map is useful in converting array reads into nested ITE
     * constructs. Suppose there are two array reads in the input
     * Read(A,i) and Read(A,j). Then Read(A,i) is replaced with a
     * symbolic constant, say v1, and Read(A,j) is replaced with the
     * following ITE:
     *
     * ITE(i=j,v1,v2)
     */
    //CAUTION: I tried using a set instead of vector for
    //readindicies. for some odd reason the performance went down
    //considerably. this is totally inexplicable.
    ASTNodeToVecMap _arrayname_readindices;
        
    /* MAP: This is a map from Array Names to nested ITE constructs,
     * which are built as described below. This map is used by the
     * TransformArray() function
     *
     * This map is useful in converting array reads into nested ITE
     * constructs. Suppose there are two array reads in the input
     * Read(A,i) and Read(A,j). Then Read(A,i) is replaced with a
     * symbolic constant, say v1, and Read(A,j) is replaced with the
     * following ITE:
     *
     * ITE(i=j,v1,v2)
     */
    ASTNodeMap _arrayread_ite;

    /*MAP: This is a map from array-reads to symbolic constants. This
     *map is used by the TransformArray()
     */
    ASTNodeMap _arrayread_symbol;

    ASTNodeSet _introduced_symbols;

    /*Memoization map for TransformFormula/TransformTerm/TransformArray function
     */
    ASTNodeMap TransformMap;
    
    //count to keep track of new symbolic constants introduced
    //corresponding to Array Reads
    unsigned int _symbol_count;

    //Formula/Term Transformers. Let Expr Manager, Type Checker
  public:
    //Functions that Transform ASTNodes
    ASTNode TransformFormula(const ASTNode& query);
    ASTNode TransformTerm(const ASTNode& term);
    ASTNode TransformArray(const ASTNode& term);
    ASTNode TranslateSignedDivMod(const ASTNode& term);

    //LET Management
  private:
    // MAP: This map is from bound IDs that occur in LETs to
    // expression. The map is useful in checking replacing the IDs
    // with the corresponding expressions.
    ASTNodeMap _letid_expr_map;
  public:

    ASTNode ResolveID(const ASTNode& var);

    //Functions that are used to manage LET expressions
    void LetExprMgr(const ASTNode& var, const ASTNode& letExpr);

    //Delete Letid Map
    void CleanupLetIDMap(void);

    //Allocate LetID map
    void InitializeLetIDMap(void);

    //Substitute Let-vars with LetExprs
    ASTNode SubstituteLetExpr(ASTNode inExpr);

    /* MAP: This is a map from MINISAT::Vars to ASTNodes
     *
     * This is a reverse map, useful in constructing
     * counterexamples. MINISAT returns a model in terms of MINISAT
     * Vars, and this map helps us convert it to a model over ASTNode
     * variables.
     */    
    vector<ASTNode> _SATVar_to_AST;

  private:        
    /* MAP: This is a map from ASTNodes to vectors of bits
     *
     * This map is used in constructing and printing
     * counterexamples. MINISAT returns values for each bit (a
     * BVGETBIT Node), and this maps allows us to assemble the bits
     * into bitvectors.
     */    
    typedef hash_map<ASTNode, hash_map<unsigned int, bool> *, 
		     ASTNode::ASTNodeHasher, 
		     ASTNode::ASTNodeEqual> ASTtoBitvectorMap;        
    ASTtoBitvectorMap _ASTNode_to_Bitvector;

    //Data structure that holds the counter-model
    ASTNodeMap CounterExampleMap;

    //Checks if the counter_example is ok. In order for the
    //counter_example to be ok, Every assert must evaluate to true 
    //w.r.t couner_example and the query must evaluate to
    //false. Otherwise the counter_example is bogus.
    void CheckCounterExample(bool t);    

    //Converts a vector of bools to a BVConst
    ASTNode BoolVectoBVConst(hash_map<unsigned,bool> * w, unsigned int l);

    //accepts a term and turns it into a constant-term w.r.t counter_example 
    ASTNode TermToConstTermUsingModel(const ASTNode& term, bool ArrayReadFlag = true);
    ASTNode Expand_ReadOverWrite_UsingModel(const ASTNode& term, bool ArrayReadFlag = true);
    //Computes the truth value of a formula w.r.t counter_example
    ASTNode ComputeFormulaUsingModel(const ASTNode& form);

    //Replaces WRITE(Arr,i,val) with ITE(j=i, val, READ(Arr,j))
    ASTNode RemoveWrites_TopLevel(const ASTNode& term);
    ASTNode RemoveWrites(const ASTNode& term);
    ASTNode SimplifyWrites_InPlace(const ASTNode& term);
    ASTNode ReadOverWrite_To_ITE(const ASTNode& term);

    ASTNode NewArrayVar(unsigned int index, unsigned int value);
    ASTNode NewVar(unsigned int valuewidth);
    //For ArrayWrite Abstraction: map from read-over-write term to
    //newname.
    ASTNodeMap ReadOverWrite_NewName_Map;
    //For ArrayWrite Refinement: Map new arraynames to Read-Over-Write
    //terms
    ASTNodeMap NewName_ReadOverWrite_Map;
    
  public:
    //print the STP solver output
    void PrintOutput(bool true_iff_valid);

    //Converts MINISAT counterexample into an AST memotable (i.e. the
    //function populates the datastructure CounterExampleMap)
    void ConstructCounterExample(MINISAT::Solver& S);

    //Prints the counterexample to stdout
    void PrintCounterExample(bool t,std::ostream& os=cout);

    //Prints the counterexample to stdout
    void PrintCounterExample_InOrder(bool t);

    //queries the counterexample, and returns the value corresponding
    //to e
    ASTNode GetCounterExample(bool t, const ASTNode& e);

    int CounterExampleSize(void) const {return CounterExampleMap.size();}

    //FIXME: This is bloody dangerous function. Hack attack to take
    //care of requests from users who want to store complete
    //counter-examples in their own data structures.
    ASTNodeMap GetCompleteCounterExample() {return CounterExampleMap;}

    // prints MINISAT assigment one bit at a time, for debugging.
    void PrintSATModel(MINISAT::Solver& S);

    //accepts constant input and normalizes it. 
    ASTNode BVConstEvaluator(const ASTNode& t);

    //FUNCTION TypeChecker: Assumes that the immediate Children of the
    //input ASTNode have been typechecked. This function is suitable
    //in scenarios like where you are building the ASTNode Tree, and
    //you typecheck as you go along. It is not suitable as a general
    //typechecker
    void BVTypeCheck(const ASTNode& n);
    
  private:
    //stack of Logical Context. each entry in the stack is a logical
    //context. A logical context is a vector of assertions. The
    //logical context is represented by a ptr to a vector of
    //assertions in that logical context. Logical contexts are created
    //by PUSH/POP
    std::vector<ASTVec *>  _asserts;
    //The query for the current logical context.
    ASTNode _current_query;

    //this flag, when true, indicates that counterexample is being
    //checked by the counterexample checker
    bool counterexample_checking_during_refinement;

    //this flag indicates as to whether the input has been determined to
    //be valid or not by this tool
    bool ValidFlag;

    //this flag, when true, indicates that a BVDIV divide by zero
    //exception occured. However, the program must not exit with a
    //fatalerror. Instead, it should evaluate the whole formula (which
    //contains the BVDIV term) to be FALSE.
    bool bvdiv_exception_occured;

  public:
    //set of functions that manipulate Logical Contexts.
    //
    //add an assertion to the current logical context
    void AddAssert(const ASTNode& assert);
    void Push(void);
    void Pop(void);
    void AddQuery(const ASTNode& q);    
    const ASTNode PopQuery();
    const ASTNode GetQuery();
    const ASTVec GetAsserts(void);

    //reports node size.  Second arg is "clearstatinfo", whatever that is.
    unsigned int NodeSize(const ASTNode& a, bool t = false);

  private:
    //This memo map is used by the ComputeFormulaUsingModel()
    ASTNodeMap ComputeFormulaMap;
    //Map for statiscal purposes
    ASTNodeSet StatInfoSet;


    ASTNodeMap TermsAlreadySeenMap;
    ASTNode CreateSubstitutionMap(const ASTNode& a);
  public:
    //prints statistics for the ASTNode. can add a prefix string c
    void ASTNodeStats(const char * c, const ASTNode& a);

    //substitution
    bool CheckSubstitutionMap(const ASTNode& a, ASTNode& output);  
    bool CheckSubstitutionMap(const ASTNode& a);
    bool UpdateSubstitutionMap(const ASTNode& e0, const ASTNode& e1);
    //if (a > b) in the termorder, then return 1
    //elseif (a < b) in the termorder, then return -1
    //else return 0
    int TermOrder(const ASTNode& a, const ASTNode& b);
    //fill the arrayname_readindices vector if e0 is a READ(Arr,index)
    //and index is a BVCONST
    void FillUp_ArrReadIndex_Vec(const ASTNode& e0, const ASTNode& e1);
    bool VarSeenInTerm(const ASTNode& var, const ASTNode& term);

    //functions for checking and updating simplifcation map
    bool CheckSimplifyMap(const ASTNode& key, ASTNode& output, bool pushNeg);
    void UpdateSimplifyMap(const ASTNode& key, const ASTNode& value, bool pushNeg);
    bool CheckAlwaysTrueFormMap(const ASTNode& key);
    void UpdateAlwaysTrueFormMap(const ASTNode& val);
    bool CheckMultInverseMap(const ASTNode& key, ASTNode& output);
    void UpdateMultInverseMap(const ASTNode& key, const ASTNode& value);

    //Map for solved variables
    bool CheckSolverMap(const ASTNode& a, ASTNode& output);
    bool CheckSolverMap(const ASTNode& a);
    bool UpdateSolverMap(const ASTNode& e0, const ASTNode& e1);
  public:
    //FIXME: HACK_ATTACK. this vector was hacked into the code to
    //support a special request by Dawson' group. They want the
    //counterexample to be printed in the order of variables declared.
    //TO BE COMMENTED LATER (say by 1st week of march,2006)
    ASTVec _special_print_set;

    //prints the initial activity levels of variables
    void PrintActivityLevels_Of_SATVars(char * init_msg, MINISAT::Solver& newS);

    //this function biases the activity levels of MINISAT variables.
    void ChangeActivityLevels_Of_SATVars(MINISAT::Solver& n);

    // Constructor
    BeevMgr() : _interior_unique_table(INITIAL_INTERIOR_UNIQUE_TABLE_SIZE),
		_symbol_unique_table(INITIAL_SYMBOL_UNIQUE_TABLE_SIZE),
		_bvconst_unique_table(INITIAL_BVCONST_UNIQUE_TABLE_SIZE),
		BBTermMemo(INITIAL_BBTERM_MEMO_TABLE_SIZE),
		BBFormMemo(INITIAL_BBFORM_MEMO_TABLE_SIZE),
		_max_node_num(0),
		ASTFalse(CreateNode(FALSE)),
		ASTTrue(CreateNode(TRUE)),
		ASTUndefined(CreateNode(UNDEFINED)),
		SimplifyMap(INITIAL_SIMPLIFY_MAP_SIZE),
		SimplifyNegMap(INITIAL_SIMPLIFY_MAP_SIZE),
		SolverMap(INITIAL_SOLVER_MAP_SIZE),
		_arrayread_symbol(INITIAL_ARRAYREAD_SYMBOL_SIZE),
		_introduced_symbols(INITIAL_INTRODUCED_SYMBOLS_SIZE),
		_symbol_count(0) { 
      _current_query = ASTUndefined;
      ValidFlag = false;
      bvdiv_exception_occured = false;
      counterexample_checking_during_refinement = false;
      start_abstracting = false;
      Begin_RemoveWrites = false;
      SimplifyWrites_InPlace_Flag = false;
    };
    
    //destructor
    ~BeevMgr();
  }; //End of Class BeevMgr


  class CompleteCounterExample {
    ASTNodeMap counterexample;
    BeevMgr * bv;
  public:
    CompleteCounterExample(ASTNodeMap a, BeevMgr* beev) : counterexample(a), bv(beev){} 
    ASTNode GetCounterExample(ASTNode e) {
      if(BOOLEAN_TYPE == e.GetType() && SYMBOL != e.GetKind()) {
	FatalError("You must input a term or propositional variables\n",e);
      }
      if(counterexample.find(e) != counterexample.end()) {
	return counterexample[e];
      }
      else {
	if(SYMBOL == e.GetKind() && BOOLEAN_TYPE == e.GetType()) {
	  return bv->CreateNode(BEEV::FALSE);
	}

	if(SYMBOL == e.GetKind()) {
	  ASTNode z = bv->CreateZeroConst(e.GetValueWidth());
	  return z;
	}

	return e;	  
      }
    }
  };

} // end namespace BEEV
#endif