C++ ASTNode::Degree方法代码示例

  /* FUNCTION: Typechecker for terms and formulas
   *
   * 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.
   *
   * If this returns, this ALWAYS returns true. If there is an error it
   * will call FatalError() and abort.
   */
  bool BVTypeCheck(const ASTNode& n)
  {
    Kind k = n.GetKind();
    //The children of bitvector terms are in turn bitvectors.
    const ASTVec& v = n.GetChildren();
    if (is_Term_kind(k))
      {
        switch (k)
          {
          case BVCONST:
            if (BITVECTOR_TYPE != n.GetType())
              FatalError("BVTypeCheck: The term t does not typecheck, where t = \n", n);
            break;
          case SYMBOL:
            return true;
          case ITE:
  			if (n.Degree() != 3)
  				FatalError("BVTypeCheck: should have exactly 3 args\n", n);
        	if (BOOLEAN_TYPE != n[0].GetType() || (n[1].GetType() != n[2].GetType()))
              FatalError("BVTypeCheck: The term t does not typecheck, where t = \n", n);
            if (n[1].GetValueWidth() != n[2].GetValueWidth())
              FatalError("BVTypeCheck: length of THENbranch != length of ELSEbranch in the term t = \n", n);
            if (n[1].GetIndexWidth() != n[2].GetIndexWidth())
              FatalError("BVTypeCheck: length of THENbranch != length of ELSEbranch in the term t = \n", n);
            break;
          case READ:
            if (n.GetChildren().size() !=2)
              FatalError("2 params to read.");
            if (n[0].GetIndexWidth() != n[1].GetValueWidth())
              {
                cerr << "Length of indexwidth of array: " << n[0] << " is : " << n[0].GetIndexWidth() << endl;
                cerr << "Length of the actual index is: " << n[1] << " is : " << n[1].GetValueWidth() << endl;
                FatalError("BVTypeCheck: length of indexwidth of array != length of actual index in the term t = \n", n);
              }
            if (ARRAY_TYPE != n[0].GetType())
              FatalError("First parameter to read should be an array", n[0]);
            if (BITVECTOR_TYPE != n[1].GetType())
              FatalError("Second parameter to read should be a bitvector", n[1]);
            break;
          case WRITE:
            if (n.GetChildren().size() !=3)
              FatalError("3 params to write.");
            if (n[0].GetIndexWidth() != n[1].GetValueWidth())
              FatalError("BVTypeCheck: length of indexwidth of array != length of actual index in the term t = \n", n);
            if (n[0].GetValueWidth() != n[2].GetValueWidth())
              FatalError("BVTypeCheck: valuewidth of array != length of actual value in the term t = \n", n);
            if (ARRAY_TYPE != n[0].GetType())
              FatalError("First parameter to read should be an array", n[0]);
            if (BITVECTOR_TYPE != n[1].GetType())
              FatalError("Second parameter to read should be a bitvector", n[1]);
            if (BITVECTOR_TYPE != n[2].GetType())
              FatalError("Third parameter to read should be a bitvector", n[2]);

            break;

          case BVDIV:
          case BVMOD:
          case BVSUB:

          case SBVDIV:
          case SBVREM:
          case SBVMOD:

          case BVLEFTSHIFT:
          case BVRIGHTSHIFT:
          case BVSRSHIFT:
          case BVVARSHIFT:
        	  if (n.Degree() != 2)
        		  FatalError("BVTypeCheck: should have exactly 2 args\n", n);
        	  // run on.
          case BVOR:
          case BVAND:
          case BVXOR:
          case BVNOR:
          case BVNAND:
          case BVXNOR:

          case BVPLUS:
          case BVMULT:
            {
              if (!(v.size() >= 2))
                FatalError("BVTypeCheck:bitwise Booleans and BV arith operators must have at least two arguments\n", n);
              unsigned int width = n.GetValueWidth();
              for (ASTVec::const_iterator it = v.begin(), itend = v.end(); it != itend; it++)
                {
                  if (width != it->GetValueWidth())
                    {
                      cerr << "BVTypeCheck:Operands of bitwise-Booleans and BV arith operators must be of equal length\n";
                      cerr << n << endl;
//.........这里部分代码省略.........

bool BVTypeCheck_term_kind(const ASTNode& n, const Kind& k)
{
  // The children of bitvector terms are in turn bitvectors.
  const ASTVec& v = n.GetChildren();

  switch (k)
  {
    case BVCONST:
      if (BITVECTOR_TYPE != n.GetType())
        FatalError("BVTypeCheck: The term t does not typecheck, where t = \n",
                   n);
      break;

    case SYMBOL:
      return true;

    case ITE:
      if (n.Degree() != 3)
        FatalError("BVTypeCheck: should have exactly 3 args\n", n);
      if (BOOLEAN_TYPE != n[0].GetType() ||
          (n[1].GetType() != n[2].GetType()))
        FatalError("BVTypeCheck: The term t does not typecheck, where t = \n",
                   n);
      if (n[1].GetValueWidth() != n[2].GetValueWidth())
        FatalError("BVTypeCheck: length of THENbranch != length of "
                   "ELSEbranch in the term t = \n",
                   n);
      if (n[1].GetIndexWidth() != n[2].GetIndexWidth())
        FatalError("BVTypeCheck: length of THENbranch != length of "
                   "ELSEbranch in the term t = \n",
                   n);
      break;

    case READ:
      if (n.GetChildren().size() != 2)
        FatalError("2 params to read.");
      if (n[0].GetIndexWidth() != n[1].GetValueWidth())
      {
        cerr << "Length of indexwidth of array: " << n[0]
             << " is : " << n[0].GetIndexWidth() << endl;
        cerr << "Length of the actual index is: " << n[1]
             << " is : " << n[1].GetValueWidth() << endl;
        FatalError("BVTypeCheck: length of indexwidth of array != length of "
                   "actual index in the term t = \n",
                   n);
      }
      if (ARRAY_TYPE != n[0].GetType())
        FatalError("First parameter to read should be an array", n[0]);
      if (BITVECTOR_TYPE != n[1].GetType())
        FatalError("Second parameter to read should be a bitvector", n[1]);
      break;

    case WRITE:
      if (n.GetChildren().size() != 3)
        FatalError("3 params to write.");
      if (n[0].GetIndexWidth() != n[1].GetValueWidth())
        FatalError("BVTypeCheck: length of indexwidth of array != length of "
                   "actual index in the term t = \n",
                   n);
      if (n[0].GetValueWidth() != n[2].GetValueWidth())
        FatalError("BVTypeCheck: valuewidth of array != length of actual "
                   "value in the term t = \n",
                   n);
      if (ARRAY_TYPE != n[0].GetType())
        FatalError("First parameter to read should be an array", n[0]);
      if (BITVECTOR_TYPE != n[1].GetType())
        FatalError("Second parameter to read should be a bitvector", n[1]);
      if (BITVECTOR_TYPE != n[2].GetType())
        FatalError("Third parameter to read should be a bitvector", n[2]);
      break;

    case BVDIV:
    case BVMOD:
    case BVSUB:

    case SBVDIV:
    case SBVREM:
    case SBVMOD:

    case BVLEFTSHIFT:
    case BVRIGHTSHIFT:
    case BVSRSHIFT:
    case BVVARSHIFT:
      if (n.Degree() != 2)
        FatalError("BVTypeCheck: should have exactly 2 args\n", n);
    // run on.
    case BVOR:
    case BVAND:
    case BVXOR:
    case BVNOR:
    case BVNAND:
    case BVXNOR:

    case BVPLUS:
    case BVMULT:
    {
      if (!(v.size() >= 2))
        FatalError("BVTypeCheck:bitwise Booleans and BV arith operators must "
                   "have at least two arguments\n",n);

//.........这里部分代码省略.........

bool BVTypeCheck_nonterm_kind(const ASTNode& n, const Kind& k)
{
  // The children of bitvector terms are in turn bitvectors.
  const ASTVec& v = n.GetChildren();

  if (!(is_Form_kind(k) && BOOLEAN_TYPE == n.GetType()))
    FatalError("BVTypeCheck: not a formula:", n);

  switch (k)
  {
    case TRUE:
    case FALSE:
    case SYMBOL:
      return true;

    case BOOLEXTRACT:
      checkChildrenAreBV(v, n);

      if (n.Degree() != 2)
        FatalError("BVTypeCheck: should have exactly 2 args\n", n);
      if (!(BVCONST == n[1].GetKind()))
        FatalError("BVTypeCheck: index should be BVCONST\n", n);
      if (n[1].GetUnsignedConst() >= n[0].GetValueWidth())
      {
        FatalError(
            "BVTypeCheck: index is greater or equal to the bitwidth.\n", n);
      }
      break;

    case PARAMBOOL:
      if (2 != n.Degree())
      {
        FatalError(
            "BVTypeCheck: PARAMBOOL formula can have exactly two childNodes",
            n);
      }
      break;

    case EQ:
      if (n.Degree() != 2)
        FatalError("BVTypeCheck: should have exactly 2 args\n", n);

      if (!(n[0].GetValueWidth() == n[1].GetValueWidth() &&
            n[0].GetIndexWidth() == n[1].GetIndexWidth()))
      {
        cerr << "valuewidth of lhs of EQ: " << n[0].GetValueWidth() << endl;
        cerr << "valuewidth of rhs of EQ: " << n[1].GetValueWidth() << endl;
        cerr << "indexwidth of lhs of EQ: " << n[0].GetIndexWidth() << endl;
        cerr << "indexwidth of rhs of EQ: " << n[1].GetIndexWidth() << endl;
        FatalError(
            "BVTypeCheck: terms in atomic formulas must be of equal length",
            n);
      }
      break;

    case BVLT:
    case BVLE:
    case BVGT:
    case BVGE:
    case BVSLT:
    case BVSLE:
    case BVSGT:
    case BVSGE:
      if (n.Degree() != 2)
        FatalError("BVTypeCheck: should have exactly 2 args\n", n);
      if (BITVECTOR_TYPE != n[0].GetType() &&
          BITVECTOR_TYPE != n[1].GetType())
      {
        FatalError("BVTypeCheck: terms in atomic formulas must be bitvectors"
                   ,n);
      }
      if (n[0].GetValueWidth() != n[1].GetValueWidth())
        FatalError(
            "BVTypeCheck: terms in atomic formulas must be of equal length",
            n);
      if (n[0].GetIndexWidth() != n[1].GetIndexWidth())
      {
        FatalError(
            "BVTypeCheck: terms in atomic formulas must be of equal length",
            n);
      }
      break;

    case NOT:
      if (1 != n.Degree())
      {
        FatalError("BVTypeCheck: NOT formula can have exactly one childNode",
                   n);
      }
      break;

    case AND:
    case OR:
    case XOR:
    case NAND:
    case NOR:
      if (2 > n.Degree())
      {
        FatalError("BVTypeCheck: AND/OR/XOR/NAND/NOR: must have atleast 2 "
                   "ChildNodes",
//.........这里部分代码省略.........

  void SMTLIB2_Print1(ostream& os, const ASTNode n, int indentation, bool letize)
  {
    //os << spaces(indentation);
    //os << endl << spaces(indentation);
    if (!n.IsDefined())
      {
        FatalError("<undefined>");
        return;
      }

    //if this node is present in the letvar Map, then print the letvar
    //this is to print letvars for shared subterms inside the printing
    //of "(LET v0 = term1, [email protected],...
	if ((NodeLetVarMap1.find(n) != NodeLetVarMap1.end()) && !letize)
      {
		SMTLIB2_Print1(os, (NodeLetVarMap1[n]), indentation, letize);
        return;
      }

    //this is to print letvars for shared subterms inside the actual
    //term to be printed
	if ((NodeLetVarMap.find(n) != NodeLetVarMap.end()) && letize)
      {
		SMTLIB2_Print1(os, (NodeLetVarMap[n]), indentation, letize);
        return;
      }

    //otherwise print it normally
	const Kind kind = n.GetKind();
    const ASTVec &c = n.GetChildren();
    switch (kind)
      {
      case BITVECTOR:
      case BVCONST:
    	  outputBitVecSMTLIB2(n, os);
        break;
      case SYMBOL:
        os << "|";
        n.nodeprint(os);
        os << "|";
        break;
      case FALSE:
        os << "false";
        break;
      case NAND: // No NAND, NOR in smtlib format.
      case NOR:
    	  assert(c.size() ==2);
    	  os << "(" << "not ";
    	  if (NAND == kind )
    		  os << "(" << "and ";
    	  else
    		  os << "(" << "or ";
    	  SMTLIB2_Print1(os, c[0], 0, letize);
    	  os << " " ;
    	  SMTLIB2_Print1(os, c[1], 0, letize);
    	  os << "))";
    	  break;
      case TRUE:
        os << "true";
        break;
      case BVSX:
      case BVZX:
        {
          unsigned int amount = c[1].GetUnsignedConst();
          if (BVZX == kind)
            os << "((_ zero_extend ";
          else
            os << "((_ sign_extend ";

          os << (amount - c[0].GetValueWidth()) << ") ";
          SMTLIB2_Print1(os, c[0], indentation, letize);
          os << ")";
        }
        break;
      case BVEXTRACT:
        {
          unsigned int upper = c[1].GetUnsignedConst();
          unsigned int lower = c[2].GetUnsignedConst();
          assert(upper >= lower);
          os << "((_ extract " << upper << " " << lower << ") ";
          SMTLIB2_Print1(os, c[0], indentation, letize);
          os << ")";
        }
        break;
  	default:
  	{
  	    if ((kind == AND  || kind == OR|| kind == XOR) && n.Degree() == 1)
  	    {
  	    	FatalError("Wrong number of arguments to operation (must be >1).", n);
  	    }

  		// SMT-LIB only allows these functions to have two parameters.
  		if ((kind == AND  || kind == OR|| kind == XOR || BVPLUS == kind || kind == BVOR || kind == BVAND)  && n.Degree() > 2)
  		{
  			string close = "";

  			for (long int i =0; i < (long int)c.size()-1; i++)
  			{
  				os << "(" << functionToSMTLIBName(kind,false);
  				os << " ";
//.........这里部分代码省略.........

string Bench_Print1(ostream &os, const ASTNode& n,
		map<ASTNode, string> *alreadyOutput)
{

	assert(((n.GetKind() == SYMBOL) || (n.GetKind() == BVCONST) || n.GetValueWidth() <= 1));
	assert(!n.IsNull());

	map<ASTNode, string>::iterator it;
	if ((it = alreadyOutput->find(n)) != alreadyOutput->end())
		return it->second;

	if (n.GetKind() == BVCONST)
	{
		(*alreadyOutput)[n] = bvconstToString(n);
		return (*alreadyOutput)[n];
	}

	if (n.GetKind() == SYMBOL)
	{
		(*alreadyOutput)[n] = symbolToString(n);
		return (*alreadyOutput)[n];
	}

	if (n.GetKind() == TRUE)
		{
		return "vdd";
		}

	if (n.GetKind() == FALSE)
		{
		return "gnd";
		}

	if (n.GetKind() == BVGETBIT)
	{
		assert(n[1].GetKind() == BVCONST);
		std::stringstream nn;
		nn << Bench_Print1(os, n[0], alreadyOutput) << "_" << Bench_Print1(os, n[1], alreadyOutput);
		(*alreadyOutput)[n] = nn.str();
		return (*alreadyOutput)[n];
	}

	std::stringstream nodeNameSS;
	nodeNameSS << "n" << n.GetNodeNum();

	string thisNode = nodeNameSS.str();
	(*alreadyOutput)[n] = thisNode;

	assert(n.Degree() > 0);
	std::stringstream output;

	// The bench format doesn't accept propositional ITEs.
	if (n.GetKind() == ITE)
	{
		assert(n.Degree() == 3);
		string p = Bench_Print1(os, n[0], alreadyOutput);
		string p1 = Bench_Print1(os, n[1], alreadyOutput);
		string p2 = Bench_Print1(os, n[2], alreadyOutput);

		os << thisNode << "_1 = AND(" << p << "," << p1 << ")" << endl;
		os << thisNode << "_2" << " = NOT(" << p << ")," << endl;
		os << thisNode << "_3" << " = AND(" << thisNode << "_2"
				<< "," << p2 << ")" << endl;
		os << thisNode << "=" << "OR(," << thisNode << "_1" << ","
				<< thisNode << "_3)" << endl;
	}
	else
	{
		if (n.Degree() > 2)
		{
			assert(n.GetKind() == AND || n.GetKind() == XOR || n.GetKind() == OR); // must be associative.
			std::deque<string> names;

			for (unsigned i = 0; i < n.Degree(); i++)
				names.push_back(Bench_Print1(os, n[i], alreadyOutput));

			int id = 0;

			while (names.size() > 2)
			{
				string a = names.front();
				names.pop_front();

				string b = names.front();
				names.pop_front();

				std::stringstream thisName;
				thisName << thisNode << "___" << id++;

				output << thisName.str() << "=" << name(n.GetKind()) << "("
						<< a << "," << b << ")" << endl;

				names.push_back(thisName.str());
			}

			assert(names.size() == 2);
			// last two now.

			string a = names.front();
			names.pop_front();
//.........这里部分代码省略.........

ASTNode ArrayTransformer::TransformTerm(const ASTNode& term)
{
  assert(TransformMap != NULL);

  const Kind k = term.GetKind();
  if (!is_Term_kind(k))
    FatalError("TransformTerm: Illegal kind: You have input a nonterm:", term,
               k);
  ASTNodeMap::const_iterator iter;
  if ((iter = TransformMap->find(term)) != TransformMap->end())
    return iter->second;

  ASTNode result;
  switch (k)
  {
    case SYMBOL:
    case BVCONST:
    {
      result = term;
      break;
    }
    case WRITE:
      FatalError("TransformTerm: this kind is not supported", term);
      break;
    case READ:
      result = TransformArrayRead(term);
      break;
    case ITE:
    {
      ASTNode cond = term[0];
      ASTNode thn = term[1];
      ASTNode els = term[2];
      cond = TransformFormula(cond);
      if (ASTTrue == cond)
        result = TransformTerm(thn);
      else if (ASTFalse == cond)
        result = TransformTerm(els);
      else
      {
        thn = TransformTerm(thn);
        els = TransformTerm(els);
        if (bm->UserFlags.optimize_flag)
          result = simp->CreateSimplifiedTermITE(cond, thn, els);
        else
          result = nf->CreateTerm(ITE, thn.GetValueWidth(), cond, thn, els);
      }
      assert(result.GetIndexWidth() == term.GetIndexWidth());
      break;
    }
    default:
    {
      const ASTVec& c = term.GetChildren();
      ASTVec::const_iterator it = c.begin();
      ASTVec::const_iterator itend = c.end();
      const unsigned width = term.GetValueWidth();
      const unsigned indexwidth = term.GetIndexWidth();
      ASTVec o;
      o.reserve(c.size());
      for (; it != itend; it++)
      {
        o.push_back(TransformTerm(*it));
      }

      if (c != o)
      {
        result = nf->CreateArrayTerm(k, indexwidth, width, o);
      }
      else
        result = term;
    }
    break;
  }

  if (term.Degree() > 0)
    (*TransformMap)[term] = result;
  if (term.GetValueWidth() != result.GetValueWidth())
    FatalError("TransformTerm: "
               "result and input terms are of different length",
               result);
  if (term.GetIndexWidth() != result.GetIndexWidth())
  {
    std::cerr << "TransformTerm: input term is : " << term << std::endl;
    FatalError("TransformTerm: "
               "result & input terms have different index length",
               result);
  }
  return result;
} 

// This doesn't rewrite changes through properly so needs to have a substitution
// applied to its output.
ASTNode PropagateEqualities::propagate(const ASTNode& a, ArrayTransformer* at)
{
  ASTNode output;
  // if the variable has been solved for, then simply return it
  if (simp->InsideSubstitutionMap(a, output))
    return output;

  if (!alreadyVisited.insert(a.GetNodeNum()).second)
  {
    return a;
  }

  output = a;

  // traverse a and populate the SubstitutionMap
  const Kind k = a.GetKind();
  if (SYMBOL == k && BOOLEAN_TYPE == a.GetType())
  {
    bool updated = simp->UpdateSubstitutionMap(a, ASTTrue);
    output = updated ? ASTTrue : a;
  }
  else if (NOT == k)
  {
    bool updated = searchXOR(a[0], ASTFalse);
    output = updated ? ASTTrue : a;
  }
  else if (IFF == k || EQ == k)
  {
    const ASTVec& c = a.GetChildren();

    if (c[0] == c[1])
      return ASTTrue;

    bool updated = simp->UpdateSubstitutionMap(c[0], c[1]);

    if (updated)
    {
      // fill the arrayname readindices vector if e0 is a
      // READ(Arr,index) and index is a BVCONST
      int to;
      if ((to = TermOrder(c[0], c[1])) == 1 && c[0].GetKind() == READ)
        at->FillUp_ArrReadIndex_Vec(c[0], c[1]);
      else if (to == -1 && c[1].GetKind() == READ)
        at->FillUp_ArrReadIndex_Vec(c[1], c[0]);
    }

    if (!updated)
      updated = searchTerm(c[0], c[1]);

    if (!updated)
      updated = searchTerm(c[1], c[0]);

    output = updated ? ASTTrue : a;
  }
  else if (XOR == k)
  {
    bool updated = searchXOR(a, ASTTrue);
    output = updated ? ASTTrue : a;

    if (updated)
      return output;

// The below block should be subsumed by the searchXOR function which
// generalises it.
// So the below block should never do anything..
#ifndef NDEBUG
    if (a.Degree() != 2)
      return output;

    int to = TermOrder(a[0], a[1]);
    if (0 == to)
    {
      if (a[0].GetKind() == NOT && a[0][0].GetKind() == EQ &&
          a[0][0][0].GetValueWidth() == 1 && a[0][0][1].GetKind() == SYMBOL)
      {
        // (XOR (NOT(= (1 v)))  ... )
        const ASTNode& symbol = a[0][0][1];
        const ASTNode newN = nf->CreateTerm(
            ITE, 1, a[1], a[0][0][0], nf->CreateTerm(BVNEG, 1, a[0][0][0]));

        if (simp->UpdateSolverMap(symbol, newN))
        {
          assert(false);
          output = ASTTrue;
        }
      }
      else if (a[1].GetKind() == NOT && a[1][0].GetKind() == EQ &&
               a[1][0][0].GetValueWidth() == 1 &&
               a[1][0][1].GetKind() == SYMBOL)
      {
        const ASTNode& symbol = a[1][0][1];
        const ASTNode newN = nf->CreateTerm(
            ITE, 1, a[0], a[1][0][0], nf->CreateTerm(BVNEG, 1, a[1][0][0]));

        if (simp->UpdateSolverMap(symbol, newN))
        {
          assert(false);
          output = ASTTrue;
//.........这里部分代码省略.........

/********************************************************
 * TransformFormula()
 *
 * Get rid of DIV/MODs, ARRAY read/writes, FOR constructs
 ********************************************************/
ASTNode ArrayTransformer::TransformFormula(const ASTNode& simpleForm)
{
  assert(TransformMap != NULL);

  const Kind k = simpleForm.GetKind();
  if (!(is_Form_kind(k) && BOOLEAN_TYPE == simpleForm.GetType()))
  {
    // FIXME: "You have inputted a NON-formula"?
    FatalError("TransformFormula:"
               "You have input a NON-formula",
               simpleForm);
  }

  ASTNodeMap::const_iterator iter;
  if ((iter = TransformMap->find(simpleForm)) != TransformMap->end())
    return iter->second;

  ASTNode result;

  switch (k)
  {
    case TRUE:
    case FALSE:
    {
      result = simpleForm;
      break;
    }
    case NOT:
    {
      ASTVec c;
      c.push_back(TransformFormula(simpleForm[0]));
      result = nf->CreateNode(NOT, c);
      break;
    }
    case BOOLEXTRACT:
    {
      ASTVec c;
      c.push_back(TransformTerm(simpleForm[0]));
      c.push_back(simpleForm[1]);
      result = nf->CreateNode(BOOLEXTRACT, c);
      break;
    }
    case BVLT:
    case BVLE:
    case BVGT:
    case BVGE:
    case BVSLT:
    case BVSLE:
    case BVSGT:
    case BVSGE:
    {
      ASTVec c;
      c.push_back(TransformTerm(simpleForm[0]));
      c.push_back(TransformTerm(simpleForm[1]));
      result = nf->CreateNode(k, c);
      break;
    }
    case EQ:
    {
      ASTNode term1 = TransformTerm(simpleForm[0]);
      ASTNode term2 = TransformTerm(simpleForm[1]);
      if (bm->UserFlags.optimize_flag)
        result = simp->CreateSimplifiedEQ(term1, term2);
      else
        result = nf->CreateNode(EQ, term1, term2);
      break;
    }
    case AND: // These could shortcut. Not sure if the extra effort is
              // justified.
    case OR:
    case NAND:
    case NOR:
    case IFF:
    case XOR:
    case ITE:
    case IMPLIES:
    {
      ASTVec vec;
      vec.reserve(simpleForm.Degree());

      for (ASTVec::const_iterator it = simpleForm.begin(),
                                  itend = simpleForm.end();
           it != itend; it++)
      {
        vec.push_back(TransformFormula(*it));
      }

      result = nf->CreateNode(k, vec);
      break;
    }
    case PARAMBOOL:
    {
      // If the parameteric boolean variable is of the form
      // VAR(const), then convert it into a Boolean variable of the
      // form "VAR(const)".
//.........这里部分代码省略.........

//.........这里部分代码省略.........
      case ITE:
        {
          ASTNode cond = term[0];
          ASTNode thn = term[1];
          ASTNode els = term[2];
          cond = TransformFormula(cond);
          if (ASTTrue == cond)
        	  result = TransformTerm(thn);
          else if (ASTFalse == cond)
        	  result = TransformTerm(els);
          else
          {
        	  thn = TransformTerm(thn);
        	  els = TransformTerm(els);
        	  result = simp->CreateSimplifiedTermITE(cond, thn, els);
          }
          assert(result.GetIndexWidth() ==term.GetIndexWidth());
          break;
        }
      default:
        {
          const ASTVec& c = term.GetChildren();
          ASTVec::const_iterator it = c.begin();
          ASTVec::const_iterator itend = c.end();
          const unsigned width = term.GetValueWidth();
          const unsigned indexwidth = term.GetIndexWidth();
          ASTVec o;
          o.reserve(c.size());
          for (; it != itend; it++)
            {
              o.push_back(TransformTerm(*it));
            }

          if (c!=o)
          {
        	  result = nf->CreateArrayTerm(k,indexwidth, width, o);
          }
          else
        	  result = term;

          const Kind k = result.GetKind();

          if (BVDIV == k 
              || BVMOD == k 
              || SBVDIV == k 
              || SBVREM == k 
              || SBVMOD == k)
            {

              // I had this as a reference, but that was wrong. Because
              // "result" gets over-written in the next block, result[1], may
              // get a reference count of zero, so be garbage collected.
              const ASTNode bottom = result[1];

              if (SBVDIV == result.GetKind() 
                  || SBVREM == result.GetKind() 
                  || SBVMOD == result.GetKind())
                {
                  result = TranslateSignedDivModRem(result);
                }

              if (bm->UserFlags.division_by_zero_returns_one_flag)
                {
                  // This is a difficult rule to introduce in other
                  // places because it's recursive. i.e.  result is
                  // embedded unchanged inside the result.

                  unsigned inputValueWidth = result.GetValueWidth();
                  ASTNode zero = bm->CreateZeroConst(inputValueWidth);
                  ASTNode one = bm->CreateOneConst(inputValueWidth);
                  result = 
                    nf->CreateTerm(ITE, inputValueWidth,
                                   nf->CreateNode(EQ, zero, bottom),
                                   one, result);

                  //return result;
                  if (bm->UserFlags.optimize_flag)
                      return simp->SimplifyTerm_TopLevel(result);
                  else
                  	return result;

                }
            }
        }
        break;
      }

    if (term.Degree() > 0)
      (*TransformMap)[term] = result;
    if (term.GetValueWidth() != result.GetValueWidth())
      FatalError("TransformTerm: "\
                 "result and input terms are of different length", result);
    if (term.GetIndexWidth() != result.GetIndexWidth())
      {
        cerr << "TransformTerm: input term is : " << term << endl;
        FatalError("TransformTerm: "\
                   "result & input terms have different index length", result);
      }
    return result;
  } //End of TransformTerm

  //FIXME: Ideally I would like the ASTNodes to be able to operate on
  //themselves (add, sub, concat, etc.) rather than doing a
  //GetBVConst() and then do the operation externally. For now,
  //this is the fastest path to completion.
  ASTNode BeevMgr::BVConstEvaluator(const ASTNode& t) {
    //cerr << "inside begin bcconstevaluator: " << t << endl;

    ASTNode OutputNode;
    if(CheckSolverMap(t,OutputNode))
      return OutputNode;
    OutputNode = ASTUndefined;

    Kind k = t.GetKind();
    unsigned long long int output = 0;
    unsigned inputwidth = t.GetValueWidth();
    ASTNode t0 = ASTUndefined;
    ASTNode t1 = ASTUndefined;
    if(2 == t.Degree()) {
      t0 = BVConstEvaluator(t[0]);
      t1 = BVConstEvaluator(t[1]);
    }
    switch(k) {
    case READ:
    case UNDEFINED:
    case WRITE:
    case SYMBOL:
      cerr << t;
      FatalError("BVConstEvaluator: term is not a constant-term",t);
      break;
    case BVCONST:
      return t;
      break;
    case BVNEG:
      //compute bitwise negation in C
      output = ~(BVConstEvaluator(t[0]).GetBVConst());
      break;
    case BVSX:
      output = SXBVConst64(BVConstEvaluator(t[0]));    
      break;
    case BVAND:
      output = t0.GetBVConst() & t1.GetBVConst();
      break;
    case BVOR:
      output = t0.GetBVConst() | t1.GetBVConst();
      break;
    case BVXOR:
      output = t0.GetBVConst() ^ t1.GetBVConst();
      break;
    case BVSUB:
      output = t0.GetBVConst() - t1.GetBVConst();
      break;
    case BVUMINUS:
      output = ~(BVConstEvaluator(t[0]).GetBVConst()) + 1;
      break;
    case BVEXTRACT: {
      unsigned long long int val = BVConstEvaluator(t[0]).GetBVConst();
      unsigned int hi = GetUnsignedConst(BVConstEvaluator(t[1]));
      unsigned int low = GetUnsignedConst(BVConstEvaluator(t[2]));

      if(!(0 <= hi <= 64))
  FatalError("ConstantEvaluator: hi bit in BVEXTRACT is > 32bits",t);
      if(!(0 <= low <= hi <= 64))
  FatalError("ConstantEvaluator: low bit in BVEXTRACT is > 32bits or hi",t);

      //64 bit mask.
      unsigned long long int mask1 = 0xffffffffffffffffLL;
      mask1 >>= 64-(hi+1);
      
      //extract val[hi:0]
      val &= mask1;
      //extract val[hi:low]
      val >>= low;
      output = val;
      break;
    }
    case BVCONCAT: {
      unsigned long long int q = BVConstEvaluator(t0).GetBVConst();
      unsigned long long int r = BVConstEvaluator(t1).GetBVConst();

      unsigned int qlen = t[0].GetValueWidth();
      unsigned int rlen = t[1].GetValueWidth();
      unsigned int slen = t.GetValueWidth();
      if(!(0 <  qlen + rlen  <= 64))
  FatalError("BVConstEvaluator:"
       "lengths of childnodes of BVCONCAT are > 64:",t);

      //64 bit mask for q
      unsigned long long int qmask = 0xffffffffffffffffLL;     
      qmask >>= 64-qlen;
      //zero the useless bits of q
      q &= qmask;

      //64 bit mask for r
      unsigned long long int rmask = 0xffffffffffffffffLL;     
      rmask >>= 64-rlen;
      //zero the useless bits of r
      r &= rmask;
      
      //concatenate
      q <<= rlen;
//.........这里部分代码省略.........

 void
 ConstantBitPropagation::scheduleDown(const ASTNode& n)
 {
   for (int i = 0; i < n.Degree(); i++)
     workList->push(n[i]);
 }