Example #1
0
literalt boolbvt::convert_ieee_float_rel(const exprt &expr)
{
  const exprt::operandst &operands=expr.operands();
  const irep_idt &rel=expr.id();

  if(operands.size()==2)
  {
    const exprt &op0=expr.op0();
    const exprt &op1=expr.op1();

    bvtypet bvtype0=get_bvtype(op0.type());
    bvtypet bvtype1=get_bvtype(op1.type());

    const bvt &bv0=convert_bv(op0);
    const bvt &bv1=convert_bv(op1);

    if(bv0.size()==bv1.size() && !bv0.empty() &&
       bvtype0==IS_FLOAT && bvtype1==IS_FLOAT)
    {
      float_utilst float_utils(prop);
      float_utils.spec=to_floatbv_type(op0.type());

      if(rel==ID_ieee_float_equal)
        return float_utils.relation(bv0, float_utilst::EQ, bv1);
      else if(rel==ID_ieee_float_notequal)
        return !float_utils.relation(bv0, float_utilst::EQ, bv1);
      else
        return SUB::convert_rest(expr);
    }
  }

  return SUB::convert_rest(expr);
}
Example #2
0
void boolbvt::convert_floatbv_typecast(
  const floatbv_typecast_exprt &expr, bvt &bv)
{
  const exprt &op0=expr.op(); // number to convert
  const exprt &op1=expr.rounding_mode(); // rounding mode

  bvt bv0=convert_bv(op0);
  bvt bv1=convert_bv(op1);

  const typet &src_type=ns.follow(expr.op0().type());
  const typet &dest_type=ns.follow(expr.type());
  
  if(src_type==dest_type) // redundant type cast?
  {
    bv=bv0;
    return;
  }

  float_utilst float_utils(prop);
  
  float_utils.set_rounding_mode(convert_bv(op1));
  
  if(src_type.id()==ID_floatbv &&
     dest_type.id()==ID_floatbv)
  {
    float_utils.spec=to_floatbv_type(src_type);
    bv=float_utils.conversion(bv0, to_floatbv_type(dest_type));
  }
  else if(src_type.id()==ID_signedbv &&
          dest_type.id()==ID_floatbv)
  {
    float_utils.spec=to_floatbv_type(dest_type);
    bv=float_utils.from_signed_integer(bv0);
  }
  else if(src_type.id()==ID_unsignedbv &&
          dest_type.id()==ID_floatbv)
  {
    float_utils.spec=to_floatbv_type(dest_type);
    bv=float_utils.from_unsigned_integer(bv0);
  }
  else if(src_type.id()==ID_floatbv &&
          dest_type.id()==ID_signedbv)
  {
    std::size_t dest_width=to_signedbv_type(dest_type).get_width();
    float_utils.spec=to_floatbv_type(src_type);
    bv=float_utils.to_signed_integer(bv0, dest_width);
  }
  else if(src_type.id()==ID_floatbv &&
          dest_type.id()==ID_unsignedbv)
  {
    std::size_t dest_width=to_unsignedbv_type(dest_type).get_width();
    float_utils.spec=to_floatbv_type(src_type);
    bv=float_utils.to_unsigned_integer(bv0, dest_width);
  }
  else
    return conversion_failed(expr, bv);
}
Example #3
0
bvt boolbvt::convert_abs(const exprt &expr)
{
    std::size_t width=boolbv_width(expr.type());

    if(width==0)
        return conversion_failed(expr);

    const exprt::operandst &operands=expr.operands();

    if(operands.size()!=1)
        throw "abs takes one operand";

    const exprt &op0=expr.op0();

    const bvt &op_bv=convert_bv(op0);

    if(op0.type()!=expr.type())
        return conversion_failed(expr);

    bvtypet bvtype=get_bvtype(expr.type());

    if(bvtype==IS_FIXED ||
            bvtype==IS_SIGNED ||
            bvtype==IS_UNSIGNED)
    {
        return bv_utils.absolute_value(op_bv);
    }
    else if(bvtype==IS_FLOAT)
    {
        float_utilst float_utils(prop);
        float_utils.spec=to_floatbv_type(expr.type());
        return float_utils.abs(op_bv);
    }

    return conversion_failed(expr);
}
Example #4
0
void boolbvt::convert_mult(const exprt &expr, bvt &bv)
{
  unsigned width=boolbv_width(expr.type());
  
  if(width==0)
    return conversion_failed(expr, bv);

  bv.resize(width);

  const exprt::operandst &operands=expr.operands();
  if(operands.size()==0)
    throw "mult without operands";

  const exprt &op0=expr.op0();

  bool no_overflow=expr.id()=="no-overflow-mult";
  
  if(expr.type().id()==ID_fixedbv)
  {
    if(op0.type()!=expr.type())
      throw "multiplication with mixed types";
    
    bv=convert_bv(op0);

    if(bv.size()!=width)
      throw "convert_mult: unexpected operand width";

    unsigned fraction_bits=
      to_fixedbv_type(expr.type()).get_fraction_bits();
             
    // do a sign extension by fraction_bits bits
    bv=bv_utils.sign_extension(bv, bv.size()+fraction_bits);
      
    for(exprt::operandst::const_iterator it=operands.begin()+1;
        it!=operands.end(); it++)
    {
      if(it->type()!=expr.type())
        throw "multiplication with mixed types";

      bvt op=convert_bv(*it);

      if(op.size()!=width)
        throw "convert_mult: unexpected operand width";

      op=bv_utils.sign_extension(op, bv.size());

      bv=bv_utils.signed_multiplier(bv, op);
    }
    
    // cut it down again
    bv.erase(bv.begin(), bv.begin()+fraction_bits);

    return;
  }
  else if(expr.type().id()==ID_floatbv)
  {
    if(op0.type()!=expr.type())
      throw "multiplication with mixed types";
    
    bv=convert_bv(op0);

    if(bv.size()!=width)
      throw "convert_mult: unexpected operand width";

    float_utilst float_utils(prop);
    float_utils.spec=to_floatbv_type(expr.type());

    for(exprt::operandst::const_iterator it=operands.begin()+1;
        it!=operands.end(); it++)
    {
      if(it->type()!=expr.type())
        throw "multiplication with mixed types";

      const bvt &op=convert_bv(*it);

      if(op.size()!=width)
        throw "convert_mult: unexpected operand width";

      bv=float_utils.mul(bv, op);
    }
    
    return;
  }
  else if(expr.type().id()==ID_unsignedbv ||
          expr.type().id()==ID_signedbv)
  {
    if(op0.type()!=expr.type())
      throw "multiplication with mixed types";
      
    bv_utilst::representationt rep=
      expr.type().id()==ID_signedbv?bv_utilst::SIGNED:
                                    bv_utilst::UNSIGNED;
    
    bv=convert_bv(op0);

    if(bv.size()!=width)
      throw "convert_mult: unexpected operand width";
      
    for(exprt::operandst::const_iterator it=operands.begin()+1;
        it!=operands.end(); it++)
    {
      if(it->type()!=expr.type())
        throw "multiplication with mixed types";

      const bvt &op=convert_bv(*it);

      if(op.size()!=width)
        throw "convert_mult: unexpected operand width";

      if(no_overflow)
        bv=bv_utils.multiplier_no_overflow(bv, op, rep);
      else
        bv=bv_utils.multiplier(bv, op, rep);
    }    

    return;
  }
  
  conversion_failed(expr, bv);
}
Example #5
0
void boolbvt::convert_add_sub(const exprt &expr, bvt &bv)
{
  const typet &type=ns.follow(expr.type());

  if(type.id()!=ID_unsignedbv &&
     type.id()!=ID_signedbv &&
     type.id()!=ID_fixedbv &&
     type.id()!=ID_floatbv &&
     type.id()!=ID_range &&
     type.id()!=ID_vector)
    return conversion_failed(expr, bv);

  unsigned width=boolbv_width(type);
  
  if(width==0)
    return conversion_failed(expr, bv);
    
  const exprt::operandst &operands=expr.operands();

  if(operands.size()==0)
    throw "operand "+expr.id_string()+" takes at least one operand";

  const exprt &op0=expr.op0();

  if(op0.type()!=type)
  {
    std::cerr << expr.pretty() << std::endl;
    throw "add/sub with mixed types";
  }

  convert_bv(op0, bv);

  if(bv.size()!=width)
    throw "convert_add_sub: unexpected operand 0 width";

  bool subtract=(expr.id()==ID_minus ||
                 expr.id()=="no-overflow-minus");
                 
  bool no_overflow=(expr.id()=="no-overflow-plus" ||
                    expr.id()=="no-overflow-minus");

  typet arithmetic_type=
    (type.id()==ID_vector)?ns.follow(type.subtype()):type;

  bv_utilst::representationt rep=
    (arithmetic_type.id()==ID_signedbv ||
     arithmetic_type.id()==ID_fixedbv)?bv_utilst::SIGNED:
                                       bv_utilst::UNSIGNED;

  for(exprt::operandst::const_iterator
      it=operands.begin()+1;
      it!=operands.end(); it++)
  {
    if(it->type()!=type)
    {
      std::cerr << expr.pretty() << std::endl;
      throw "add/sub with mixed types";
    }

    bvt op;
    convert_bv(*it, op);

    if(op.size()!=width)
      throw "convert_add_sub: unexpected operand width";

    if(type.id()==ID_vector)
    {
      const typet &subtype=ns.follow(type.subtype());
    
      unsigned sub_width=boolbv_width(subtype);

      if(sub_width==0 || width%sub_width!=0)
        throw "convert_add_sub: unexpected vector operand width";

      unsigned size=width/sub_width;
      bv.resize(width);

      for(unsigned i=0; i<size; i++)
      {
        bvt tmp_op;
        tmp_op.resize(sub_width);

        for(unsigned j=0; j<tmp_op.size(); j++)
        {
          assert(i*sub_width+j<op.size());
          tmp_op[j]=op[i*sub_width+j];
        }
        
        bvt tmp_result;
        tmp_result.resize(sub_width);

        for(unsigned j=0; j<tmp_result.size(); j++)
        {
          assert(i*sub_width+j<bv.size());
          tmp_result[j]=bv[i*sub_width+j];
        }
        
        if(type.subtype().id()==ID_floatbv)
        {
          #ifdef HAVE_FLOATBV
          float_utilst float_utils(prop);
          float_utils.spec=to_floatbv_type(subtype);
          tmp_result=float_utils.add_sub(tmp_result, tmp_op, subtract);
          #else
          return conversion_failed(expr, bv);
          #endif
        }
        else
          tmp_result=bv_utils.add_sub(tmp_result, tmp_op, subtract);
      
        assert(tmp_result.size()==sub_width);
        
        for(unsigned j=0; j<tmp_result.size(); j++)
        {
          assert(i*sub_width+j<bv.size());
          bv[i*sub_width+j]=tmp_result[j];
        }
      }
    }
    else if(type.id()==ID_floatbv)
    {
      #ifdef HAVE_FLOATBV
      float_utilst float_utils(prop);
      float_utils.spec=to_floatbv_type(arithmetic_type);
      bv=float_utils.add_sub(bv, op, subtract);
      #else
      return conversion_failed(expr, bv);
      #endif
    }
    else if(no_overflow)
      bv=bv_utils.add_sub_no_overflow(bv, op, subtract, rep);
    else
      bv=bv_utils.add_sub(bv, op, subtract);
  }
}
Example #6
0
bool boolbvt::type_conversion(
  const typet &src_type, const bvt &src,
  const typet &dest_type, bvt &dest)
{
  bvtypet dest_bvtype=get_bvtype(dest_type);
  bvtypet src_bvtype=get_bvtype(src_type);
  
  if(src_bvtype==IS_C_BIT_FIELD)
    return type_conversion(
      c_bit_field_replacement_type(to_c_bit_field_type(src_type), ns), src, dest_type, dest);

  if(dest_bvtype==IS_C_BIT_FIELD)
    return type_conversion(
      src_type, src, c_bit_field_replacement_type(to_c_bit_field_type(dest_type), ns), dest);

  std::size_t src_width=src.size();
  std::size_t dest_width=boolbv_width(dest_type);
  
  if(dest_width==0 || src_width==0)
    return true;
  
  dest.clear();
  dest.reserve(dest_width);

  if(dest_type.id()==ID_complex)
  {
    if(src_type==dest_type.subtype())
    {
      forall_literals(it, src)
      dest.push_back(*it);

      // pad with zeros
      for(std::size_t i=src.size(); i<dest_width; i++)
        dest.push_back(const_literal(false));

      return false;
    }
    else if(src_type.id()==ID_complex)
    {
      // recursively do both halfs
      bvt lower, upper, lower_res, upper_res;
      lower.assign(src.begin(), src.begin()+src.size()/2);
      upper.assign(src.begin()+src.size()/2, src.end());
      type_conversion(ns.follow(src_type.subtype()), lower, ns.follow(dest_type.subtype()), lower_res);
      type_conversion(ns.follow(src_type.subtype()), upper, ns.follow(dest_type.subtype()), upper_res);
      assert(lower_res.size()+upper_res.size()==dest_width);
      dest=lower_res;
      dest.insert(dest.end(), upper_res.begin(), upper_res.end());
      return false;
    }
  }
  
  if(src_type.id()==ID_complex)
  {
    assert(dest_type.id()!=ID_complex);
    if(dest_type.id()==ID_signedbv ||
       dest_type.id()==ID_unsignedbv ||
       dest_type.id()==ID_floatbv ||
       dest_type.id()==ID_fixedbv ||
       dest_type.id()==ID_c_enum ||
       dest_type.id()==ID_c_enum_tag ||
       dest_type.id()==ID_bool)
    {
      // A cast from complex x to real T
      // is (T) __real__ x.
      bvt tmp_src(src);
      tmp_src.resize(src.size()/2); // cut off imag part
      return type_conversion(src_type.subtype(), tmp_src, dest_type, dest);
    }
  }
  
  switch(dest_bvtype)
  {
  case IS_RANGE:
    if(src_bvtype==IS_UNSIGNED ||
       src_bvtype==IS_SIGNED ||
       src_bvtype==IS_C_BOOL)
    {
      mp_integer dest_from=to_range_type(dest_type).get_from();

      if(dest_from==0)
      {
        // do zero extension
        dest.resize(dest_width);
        for(std::size_t i=0; i<dest.size(); i++)
          dest[i]=(i<src.size()?src[i]:const_literal(false));

        return false;
      }
    }
    else if(src_bvtype==IS_RANGE) // range to range
    {
      mp_integer src_from=to_range_type(src_type).get_from();
      mp_integer dest_from=to_range_type(dest_type).get_from();

      if(dest_from==src_from)
      {
        // do zero extension, if needed
        dest=bv_utils.zero_extension(src, dest_width);
        return false;
      }
      else
      {
        // need to do arithmetic: add src_from-dest_from
        mp_integer offset=src_from-dest_from;
        dest=
          bv_utils.add(
            bv_utils.zero_extension(src, dest_width),
            bv_utils.build_constant(offset, dest_width));
      }

      return false;
    }
    break;
    
  case IS_FLOAT: // to float
    {
      float_utilst float_utils(prop);
      
      switch(src_bvtype)
      {
      case IS_FLOAT: // float to float
        // we don't have a rounding mode here,
        // which is why we refuse.
        break;

      case IS_SIGNED: // signed to float
      case IS_C_ENUM:
        float_utils.spec=to_floatbv_type(dest_type);
        dest=float_utils.from_signed_integer(src);
        return false;

      case IS_UNSIGNED: // unsigned to float
      case IS_C_BOOL: // _Bool to float
        float_utils.spec=to_floatbv_type(dest_type);
        dest=float_utils.from_unsigned_integer(src);
        return false;

      case IS_BV:
        assert(src_width==dest_width);
        dest=src;
        return false;

      default:
        if(src_type.id()==ID_bool)
        {
          // bool to float
          
          // build a one
          ieee_floatt f;
          f.spec=to_floatbv_type(dest_type);
          f.from_integer(1);
          
          dest=convert_bv(f.to_expr());

          assert(src_width==1);
          
          Forall_literals(it, dest)
            *it=prop.land(*it, src[0]);
            
          return false;
        }
      }
    }
    break;

  case IS_FIXED:
    if(src_bvtype==IS_FIXED)
    {
      // fixed to fixed
      
      std::size_t dest_fraction_bits=to_fixedbv_type(dest_type).get_fraction_bits(),
                  dest_int_bits=dest_width-dest_fraction_bits;
      std::size_t op_fraction_bits=to_fixedbv_type(src_type).get_fraction_bits(),
                  op_int_bits=src_width-op_fraction_bits;
      
      dest.resize(dest_width);
      
      // i == position after dot
      // i == 0: first position after dot

      for(std::size_t i=0; i<dest_fraction_bits; i++)
      {
        // position in bv
        std::size_t p=dest_fraction_bits-i-1;
      
        if(i<op_fraction_bits)
          dest[p]=src[op_fraction_bits-i-1];
        else 
          dest[p]=const_literal(false); // zero padding
      }

      for(std::size_t i=0; i<dest_int_bits; i++)
      {
        // position in bv
        std::size_t p=dest_fraction_bits+i;
        assert(p<dest_width);
      
        if(i<op_int_bits)
          dest[p]=src[i+op_fraction_bits];
        else 
          dest[p]=src[src_width-1]; // sign extension
      }

      return false;
    }
    else if(src_bvtype==IS_BV)
    {
      assert(src_width==dest_width);
      dest=src;
      return false;
    }
    else if(src_bvtype==IS_UNSIGNED ||
            src_bvtype==IS_SIGNED ||
            src_bvtype==IS_C_BOOL ||
            src_bvtype==IS_C_ENUM)
    {
      // integer to fixed

      std::size_t dest_fraction_bits=
        to_fixedbv_type(dest_type).get_fraction_bits();

      for(std::size_t i=0; i<dest_fraction_bits; i++)
        dest.push_back(const_literal(false)); // zero padding

      for(std::size_t i=0; i<dest_width-dest_fraction_bits; i++)
      {
        literalt l;
      
        if(i<src_width)
          l=src[i];
        else
        {
          if(src_bvtype==IS_SIGNED || src_bvtype==IS_C_ENUM)
            l=src[src_width-1]; // sign extension
          else
            l=const_literal(false); // zero extension
        }
        
        dest.push_back(l);
      }

      return false;
    }
    else if(src_type.id()==ID_bool)
    {
      // bool to fixed
      std::size_t fraction_bits=
        to_fixedbv_type(dest_type).get_fraction_bits();

      assert(src_width==1);

      for(std::size_t i=0; i<dest_width; i++)
      {
        if(i==fraction_bits)
          dest.push_back(src[0]);
        else
          dest.push_back(const_literal(false));
      }

      return false;
    }
    break;
  
  case IS_UNSIGNED:
  case IS_SIGNED:
  case IS_C_ENUM:
    switch(src_bvtype)
    {
    case IS_FLOAT: // float to integer
      // we don't have a rounding mode here,
      // which is why we refuse.
      break;
     
    case IS_FIXED: // fixed to integer
      {
        std::size_t op_fraction_bits=
          to_fixedbv_type(src_type).get_fraction_bits();

        for(std::size_t i=0; i<dest_width; i++)
        {
          if(i<src_width-op_fraction_bits)
            dest.push_back(src[i+op_fraction_bits]);
          else
          {
            if(dest_bvtype==IS_SIGNED)
              dest.push_back(src[src_width-1]); // sign extension
            else
              dest.push_back(const_literal(false)); // zero extension
          }
        }
        
        // we might need to round up in case of negative numbers
        // e.g., (int)(-1.00001)==1
        
        bvt fraction_bits_bv=src;
        fraction_bits_bv.resize(op_fraction_bits);
        literalt round_up=
          prop.land(prop.lor(fraction_bits_bv), src.back());

        dest=bv_utils.incrementer(dest, round_up);

        return false;
      }

    case IS_UNSIGNED: // integer to integer
    case IS_SIGNED:
    case IS_C_ENUM:
    case IS_C_BOOL:
      {
        // We do sign extension for any source type
        // that is signed, independently of the
        // destination type.
        // E.g., ((short)(ulong)(short)-1)==-1
        bool sign_extension=
          src_bvtype==IS_SIGNED || src_bvtype==IS_C_ENUM;

        for(std::size_t i=0; i<dest_width; i++)
        {
          if(i<src_width)
            dest.push_back(src[i]);
          else if(sign_extension)
            dest.push_back(src[src_width-1]); // sign extension
          else
            dest.push_back(const_literal(false));
        }

        return false;
      }
      
    case IS_VERILOG_UNSIGNED: // verilog_unsignedbv to signed/unsigned/enum
      {
        for(std::size_t i=0; i<dest_width; i++)
        {
          std::size_t src_index=i*2; // we take every second bit

          if(src_index<src_width)
            dest.push_back(src[src_index]);
          else // always zero-extend
            dest.push_back(const_literal(false));
        }

        return false;
      }
      break;
      
    case IS_VERILOG_SIGNED: // verilog_signedbv to signed/unsigned/enum
      {
        for(std::size_t i=0; i<dest_width; i++)
        {
          std::size_t src_index=i*2; // we take every second bit

          if(src_index<src_width)
            dest.push_back(src[src_index]);
          else // always sign-extend
            dest.push_back(src.back());
        }

        return false;
      }
      break;
      
    default:
      if(src_type.id()==ID_bool)
      {
        // bool to integer

        assert(src_width==1);

        for(std::size_t i=0; i<dest_width; i++)
        {
          if(i==0)
            dest.push_back(src[0]);
          else
            dest.push_back(const_literal(false));
        }

        return false;
      }
    }
    break;
    
  case IS_VERILOG_UNSIGNED:
    if(src_bvtype==IS_UNSIGNED ||
       src_bvtype==IS_C_BOOL ||
       src_type.id()==ID_bool)
    {
      for(std::size_t i=0, j=0; i<dest_width; i+=2, j++)
      {
        if(j<src_width)
          dest.push_back(src[j]);
        else
          dest.push_back(const_literal(false));

        dest.push_back(const_literal(false));
      }

      return false;
    }
    else if(src_bvtype==IS_SIGNED)
    {
      for(std::size_t i=0, j=0; i<dest_width; i+=2, j++)
      {
        if(j<src_width)
          dest.push_back(src[j]);
        else
          dest.push_back(src.back());

        dest.push_back(const_literal(false));
      }

      return false;
    }
    else if(src_bvtype==IS_VERILOG_UNSIGNED)
    {
      // verilog_unsignedbv to verilog_unsignedbv
      dest=src;

      if(dest_width<src_width)
        dest.resize(dest_width);
      else
      {
        dest=src;
        while(dest.size()<dest_width)
        {
          dest.push_back(const_literal(false));
          dest.push_back(const_literal(false));
        }
      }
      return false;
    }
    break;

  case IS_BV:
    assert(src_width==dest_width);
    dest=src;
    return false;
    
  case IS_C_BOOL:
    dest.resize(dest_width, const_literal(false));

    if(src_bvtype==IS_FLOAT)
    {
      float_utilst float_utils(prop);
      float_utils.spec=to_floatbv_type(src_type);
      dest[0]=!float_utils.is_zero(src);
    }
    else if(src_bvtype==IS_C_BOOL)
      dest[0]=src[0];
    else
      dest[0]=!bv_utils.is_zero(src);

    return false;
    
  default:
    if(dest_type.id()==ID_array)
    {
      if(src_width==dest_width)
      {
        dest=src;
        return false;
      }
    }
    else if(dest_type.id()==ID_struct)
    {
      const struct_typet &dest_struct =
        to_struct_type(dest_type);

      if(src_type.id()==ID_struct)
      {
        // we do subsets

        dest.resize(dest_width, const_literal(false));

        const struct_typet &op_struct =
          to_struct_type(src_type);

        const struct_typet::componentst &dest_comp=
          dest_struct.components();

        const struct_typet::componentst &op_comp=
          op_struct.components();

        // build offset maps
        offset_mapt op_offsets, dest_offsets;

        build_offset_map(op_struct, op_offsets);
        build_offset_map(dest_struct, dest_offsets);

        // build name map
        typedef std::map<irep_idt, unsigned> op_mapt;
        op_mapt op_map;

        for(std::size_t i=0; i<op_comp.size(); i++)
          op_map[op_comp[i].get_name()]=i;

        // now gather required fields
        for(std::size_t i=0;
            i<dest_comp.size();
            i++)
        {
          std::size_t offset=dest_offsets[i];
          std::size_t comp_width=boolbv_width(dest_comp[i].type());
          if(comp_width==0) continue;

          op_mapt::const_iterator it=
            op_map.find(dest_comp[i].get_name());

          if(it==op_map.end())
          {
            // not found

            // filling with free variables
            for(std::size_t j=0; j<comp_width; j++)
              dest[offset+j]=prop.new_variable();
          }
          else
          {
            // found
            if(dest_comp[i].type()!=dest_comp[it->second].type())
            {
              // filling with free variables
              for(std::size_t j=0; j<comp_width; j++)
                dest[offset+j]=prop.new_variable();
            }
            else
            {
              std::size_t op_offset=op_offsets[it->second];
              for(std::size_t j=0; j<comp_width; j++)
                dest[offset+j]=src[op_offset+j];
            }
          }
        }

        return false;
      }
    }

  }

  return true;
}
Example #7
0
void boolbvt::convert_unary_minus(const exprt &expr, bvt &bv)
{
  const typet &type=ns.follow(expr.type());

  unsigned width=boolbv_width(type);
  
  if(width==0)
    return conversion_failed(expr, bv);

  const exprt::operandst &operands=expr.operands();

  if(operands.size()!=1)
    throw "unary minus takes one operand";
    
  const exprt &op0=expr.op0();

  const bvt &op_bv=convert_bv(op0);

  bvtypet bvtype=get_bvtype(type);
  bvtypet op_bvtype=get_bvtype(op0.type());
  unsigned op_width=op_bv.size();

  bool no_overflow=(expr.id()=="no-overflow-unary-minus");
  
  if(op_width==0 || op_width!=width)
    return conversion_failed(expr, bv);

  if(bvtype==IS_UNKNOWN &&
     (type.id()==ID_vector || type.id()==ID_complex))
  {
    const typet &subtype=ns.follow(type.subtype());
  
    unsigned sub_width=boolbv_width(subtype);

    if(sub_width==0 || width%sub_width!=0)
      throw "unary-: unexpected vector operand width";

    unsigned size=width/sub_width;
    bv.resize(width);

    for(unsigned i=0; i<size; i++)
    {
      bvt tmp_op;
      tmp_op.resize(sub_width);

      for(unsigned j=0; j<tmp_op.size(); j++)
      {
        assert(i*sub_width+j<op_bv.size());
        tmp_op[j]=op_bv[i*sub_width+j];
      }
      
      bvt tmp_result;
      
      if(type.subtype().id()==ID_floatbv)
      {
        float_utilst float_utils(prop);
        float_utils.spec=to_floatbv_type(subtype);
        tmp_result=float_utils.negate(tmp_op);
      }
      else
        tmp_result=bv_utils.negate(tmp_op);
    
      assert(tmp_result.size()==sub_width);
      
      for(unsigned j=0; j<tmp_result.size(); j++)
      {
        assert(i*sub_width+j<bv.size());
        bv[i*sub_width+j]=tmp_result[j];
      }
    }

    return;
  }
  else if(bvtype==IS_FIXED && op_bvtype==IS_FIXED)
  {
    if(no_overflow)
      bv=bv_utils.negate_no_overflow(op_bv);
    else
      bv=bv_utils.negate(op_bv);

    return;
  }
  else if(bvtype==IS_FLOAT && op_bvtype==IS_FLOAT)
  {
    assert(!no_overflow);
    float_utilst float_utils(prop);
    float_utils.spec=to_floatbv_type(expr.type());
    bv=float_utils.negate(op_bv);
    return;
  }
  else if((op_bvtype==IS_SIGNED || op_bvtype==IS_UNSIGNED) &&
          (bvtype==IS_SIGNED || bvtype==IS_UNSIGNED))
  {
    if(no_overflow)
      prop.l_set_to(bv_utils.overflow_negate(op_bv), false);

    if(no_overflow)
      bv=bv_utils.negate_no_overflow(op_bv);
    else
      bv=bv_utils.negate(op_bv);

    return;
  }

  conversion_failed(expr, bv);
}
Example #8
0
void boolbvt::convert_floatbv_op(const exprt &expr, bvt &bv)
{
  const exprt::operandst &operands=expr.operands();
  
  if(operands.size()!=3)
    throw "operator "+expr.id_string()+" takes three operands";

  const exprt &op0=expr.op0(); // first operand
  const exprt &op1=expr.op1(); // second operand
  const exprt &op2=expr.op2(); // rounding mode

  bvt bv0=convert_bv(op0);
  bvt bv1=convert_bv(op1);
  bvt bv2=convert_bv(op2);

  const typet &type=ns.follow(expr.type());

  if(op0.type()!=type || op1.type()!=type)
  {
    std::cerr << expr.pretty() << std::endl;
    throw "float op with mixed types";
  }

  float_utilst float_utils(prop);
  
  float_utils.set_rounding_mode(bv2);

  if(type.id()==ID_floatbv)
  {
    float_utils.spec=to_floatbv_type(expr.type());

    if(expr.id()==ID_floatbv_plus)
      bv=float_utils.add_sub(bv0, bv1, false);
    else if(expr.id()==ID_floatbv_minus)
      bv=float_utils.add_sub(bv0, bv1, true);
    else if(expr.id()==ID_floatbv_mult)
      bv=float_utils.mul(bv0, bv1);
    else if(expr.id()==ID_floatbv_div)
      bv=float_utils.div(bv0, bv1);
    else if(expr.id()==ID_floatbv_rem)
      bv=float_utils.rem(bv0, bv1);
    else
      assert(false);
  }
  else if(type.id()==ID_vector || type.id()==ID_complex)
  {
    const typet &subtype=ns.follow(type.subtype());
    
    if(subtype.id()==ID_floatbv)
    {
      float_utils.spec=to_floatbv_type(subtype);

      std::size_t width=boolbv_width(type);
      std::size_t sub_width=boolbv_width(subtype);

      if(sub_width==0 || width%sub_width!=0)
        throw "convert_floatbv_op: unexpected vector operand width";

      std::size_t size=width/sub_width;
      bv.resize(width);

      for(std::size_t i=0; i<size; i++)
      {
        bvt tmp_bv0, tmp_bv1, tmp_bv;
        
        tmp_bv0.assign(bv0.begin()+i*sub_width, bv0.begin()+(i+1)*sub_width);
        tmp_bv1.assign(bv1.begin()+i*sub_width, bv1.begin()+(i+1)*sub_width);

        if(expr.id()==ID_floatbv_plus)
          tmp_bv=float_utils.add_sub(tmp_bv0, tmp_bv1, false);
        else if(expr.id()==ID_floatbv_minus)
          tmp_bv=float_utils.add_sub(tmp_bv0, tmp_bv1, true);
        else if(expr.id()==ID_floatbv_mult)
          tmp_bv=float_utils.mul(tmp_bv0, tmp_bv1);
        else if(expr.id()==ID_floatbv_div)
          tmp_bv=float_utils.div(tmp_bv0, tmp_bv1);
        else
          assert(false);

        assert(tmp_bv.size()==sub_width);
        assert(i*sub_width+sub_width-1<bv.size());
        std::copy(tmp_bv.begin(), tmp_bv.end(), bv.begin()+i*sub_width);
      }
    }
    else
      return conversion_failed(expr, bv);
  }
  else
    return conversion_failed(expr, bv);
}
Example #9
0
void bv_refinementt::check_UNSAT(approximationt &a)
{
  // part of the conflict?
  if(!is_in_conflict(a)) return;

  status() << "Found assumption for `" << a.as_string()
           << "' in proof (state " << a.under_state << ")" << eom;

  assert(!a.under_assumptions.empty());

  a.under_assumptions.clear();

  if(a.expr.type().id()==ID_floatbv)
  {
    const floatbv_typet &floatbv_type=to_floatbv_type(a.expr.type());
    ieee_float_spect spec=floatbv_type;

    a.under_assumptions.reserve(a.op0_bv.size()+a.op1_bv.size());

    float_utilst float_utils(prop);
    float_utils.spec=spec;

    // the fraction without hidden bit
    const bvt fraction0=float_utils.get_fraction(a.op0_bv);
    const bvt fraction1=float_utils.get_fraction(a.op1_bv);
    
    if(a.under_state==0)
    {
      // we first set sign and exponent free,
      // but keep the fraction zero

      for(unsigned i=0; i<fraction0.size(); i++)
        a.add_under_assumption(prop.lnot(fraction0[i]));

      for(unsigned i=0; i<fraction1.size(); i++)
        a.add_under_assumption(prop.lnot(fraction1[i]));
    }
    else
    {
      // now fraction: make this grow quadratically
      unsigned x=a.under_state*a.under_state;
  
      if(x>=MAX_FLOAT_UNDERAPPROX && x>=a.result_bv.size())
      {
        // make it free altogether, this guarantees progress
      }
      else
      {
        // set x bits of both exponent and mantissa free
        // need to start with most-significant bits

        #if 0
        for(unsigned i=x; i<fraction0.size(); i++)
          a.add_under_assumption(prop.lnot(
            fraction0[fraction0.size()-i-1]));

        for(unsigned i=x; i<fraction1.size(); i++)
          a.add_under_assumption(prop.lnot(
            fraction1[fraction1.size()-i-1]));
        #endif
      }
    }
  }
  else
  {
    unsigned x=a.under_state+1;
  
    if(x>=MAX_INTEGER_UNDERAPPROX && x>=a.result_bv.size())
    {
      // make it free altogether, this guarantees progress
    }
    else
    {
      // set x least-significant bits free
      a.under_assumptions.reserve(a.op0_bv.size()+a.op1_bv.size());

      for(unsigned i=x; i<a.op0_bv.size(); i++)
        a.add_under_assumption(prop.lnot(a.op0_bv[i]));

      for(unsigned i=x; i<a.op1_bv.size(); i++)
        a.add_under_assumption(prop.lnot(a.op1_bv[i]));
    }
  }

  a.under_state++;
  progress=true;
}
Example #10
0
void bv_refinementt::check_SAT(approximationt &a)
{
  // get values
  get_values(a);

  // see if the satisfying assignment is spurious in any way

  const typet &type=ns.follow(a.expr.type());
  
  if(type.id()==ID_floatbv)
  {
    // these are all trinary
    assert(a.expr.operands().size()==3);

    if(a.over_state==MAX_STATE) return;
  
    ieee_float_spect spec(to_floatbv_type(type));
    ieee_floatt o0(spec), o1(spec);

    o0.unpack(a.op0_value);
    o1.unpack(a.op1_value);
    
    ieee_floatt result=o0;
    o0.rounding_mode=RM;
    o1.rounding_mode=RM;
    result.rounding_mode=RM;

    if(a.expr.id()==ID_floatbv_plus)
      result+=o1;
    else if(a.expr.id()==ID_floatbv_minus)
      result-=o1;
    else if(a.expr.id()==ID_floatbv_mult)
      result*=o1;
    else if(a.expr.id()==ID_floatbv_div)
      result/=o1;
    else
      assert(false);

    if(result.pack()==a.result_value) // ok
      return;
      
    #ifdef DEBUG
    ieee_floatt rr(spec);
    rr.unpack(a.result_value);
    
    std::cout << "S1: " << o0 << " " << a.expr.id() << " " << o1
              << " != " << rr << std::endl;
    std::cout << "S2: " << integer2binary(a.op0_value, spec.width())
                        << " " << a.expr.id() << " " <<
                           integer2binary(a.op1_value, spec.width())
              << "!=" << integer2binary(a.result_value, spec.width()) << std::endl;
    std::cout << "S3: " << integer2binary(a.op0_value, spec.width())
                        << " " << a.expr.id() << " " <<
                           integer2binary(a.op1_value, spec.width())
              << "==" << integer2binary(result.pack(), spec.width()) << std::endl;
    #endif
  
    //if(a.over_state==1) { std::cout << "DISAGREEMENT!\n"; exit(1); }
    
    if(a.over_state<max_node_refinement)
    {
      bvt r;
      float_utilst float_utils(prop);
      float_utils.spec=spec;
      float_utils.rounding_mode_bits.set(RM);
      
      literalt op0_equal=
        bv_utils.equal(a.op0_bv, float_utils.build_constant(o0));
      
      literalt op1_equal=
        bv_utils.equal(a.op1_bv, float_utils.build_constant(o1));
        
      literalt result_equal=
        bv_utils.equal(a.result_bv, float_utils.build_constant(result));
      
      literalt op0_and_op1_equal=
        prop.land(op0_equal, op1_equal);
      
      prop.l_set_to_true(
        prop.limplies(op0_and_op1_equal, result_equal));
    }
    else
    {
      // give up
      // remove any previous over-approximation
      a.over_assumptions.clear();
      a.over_state=MAX_STATE;
    
      bvt r;
      float_utilst float_utils(prop);
      float_utils.spec=spec;
      float_utils.rounding_mode_bits.set(RM);

      bvt op0=a.op0_bv, op1=a.op1_bv, res=a.result_bv;

      if(a.expr.id()==ID_floatbv_plus)
        r=float_utils.add(op0, op1);
      else if(a.expr.id()==ID_floatbv_minus)
        r=float_utils.sub(op0, op1);
      else if(a.expr.id()==ID_floatbv_mult)
        r=float_utils.mul(op0, op1);
      else if(a.expr.id()==ID_floatbv_div)
        r=float_utils.div(op0, op1);
      else
        assert(0);

      assert(r.size()==res.size());
      bv_utils.set_equal(r, res);
    }
  }
  else if(type.id()==ID_signedbv ||
          type.id()==ID_unsignedbv)
  {
    // these are all binary
    assert(a.expr.operands().size()==2);

    // already full interpretation?
    if(a.over_state>0) return;
  
    bv_spect spec(type);
    bv_arithmetict o0(spec), o1(spec);
    o0.unpack(a.op0_value);
    o1.unpack(a.op1_value);

    // division by zero is never spurious

    if((a.expr.id()==ID_div || a.expr.id()==ID_mod) &&
       o1==0)
      return;

    if(a.expr.id()==ID_mult)
      o0*=o1;
    else if(a.expr.id()==ID_div)
      o0/=o1;
    else if(a.expr.id()==ID_mod)
      o0%=o1;
    else
      assert(false);

    if(o0.pack()==a.result_value) // ok
      return;

    if(a.over_state==0)
    {
      // we give up right away and add the full interpretation
      bvt r;
      if(a.expr.id()==ID_mult)
      {
        r=bv_utils.multiplier(
          a.op0_bv, a.op1_bv,
          a.expr.type().id()==ID_signedbv?bv_utilst::SIGNED:bv_utilst::UNSIGNED);
      }
      else if(a.expr.id()==ID_div)
      {
        r=bv_utils.divider(
          a.op0_bv, a.op1_bv,
          a.expr.type().id()==ID_signedbv?bv_utilst::SIGNED:bv_utilst::UNSIGNED);
      }
      else if(a.expr.id()==ID_mod)
      {
        r=bv_utils.remainder(
          a.op0_bv, a.op1_bv,
          a.expr.type().id()==ID_signedbv?bv_utilst::SIGNED:bv_utilst::UNSIGNED);
      }
      else
        assert(0);

      bv_utils.set_equal(r, a.result_bv);
    }
    else
      assert(0);
  }
  else
    assert(0);

  status() << "Found spurious `" << a.as_string()
           << "' (state " << a.over_state << ")" << eom;

  progress=true;
  if(a.over_state<MAX_STATE)
    a.over_state++;
}