public static DataType?GetResult(this ArithmeticOperation operation, DataType lhs, DataType rhs, out bool verifiable)
{
Contract.Requires(operation.IsBinary());
Contract.Requires(lhs.IsStackType());
Contract.Requires(rhs.IsStackType());
verifiable = true;
switch (operation)
{
// ECMA 335 III.1.5 Table 2: Binary Numeric Operations (add, div, mul, rem, sub)
case ArithmeticOperation.Addition:
case ArithmeticOperation.Division:
case ArithmeticOperation.Multiplication:
case ArithmeticOperation.Remainder:
case ArithmeticOperation.Subtraction:
// ECMA 335 III.1.5 Table 7: Overflow Arithmetic Operations (add.ovf, add.ovf.un, mul.ovf, mul.ovf.un, sub.ovf, sub.ovf.un)
case ArithmeticOperation.Addition_OverflowCheck:
case ArithmeticOperation.Addition_UnsignedWithOverflowCheck:
case ArithmeticOperation.Multiplication_OverflowCheck:
case ArithmeticOperation.Multiplication_UnsignedWithOverflowCheck:
case ArithmeticOperation.Subtraction_OverflowCheck:
case ArithmeticOperation.Subtraction_UnsignedWithOverflowCheck:
if (lhs == rhs)
{
if (lhs.IsIntegerStackType())
{
return(lhs);
}
if (lhs.IsFloat() && !operation.IsOverflowChecked())
{
return(lhs);
}
if (lhs.IsManagedPointer() && (operation == ArithmeticOperation.Subtraction ||
operation == ArithmeticOperation.Subtraction_UnsignedWithOverflowCheck))
{
verifiable = false;
return(DataType.NativeInt);
}
}
else
{
if ((lhs == DataType.Int32 && rhs == DataType.NativeInt) ||
(lhs == DataType.NativeInt && rhs == DataType.Int32))
{
return(DataType.NativeInt);
}
if (lhs.IsManagedPointer() && (rhs == DataType.Int32 || rhs == DataType.NativeInt) &&
(operation == ArithmeticOperation.Addition || operation == ArithmeticOperation.Subtraction ||
operation == ArithmeticOperation.Addition_UnsignedWithOverflowCheck ||
operation == ArithmeticOperation.Subtraction_UnsignedWithOverflowCheck))
{
verifiable = false;
return(lhs);
}
if ((lhs == DataType.Int32 || lhs == DataType.NativeInt) && rhs.IsManagedPointer() &&
(operation == ArithmeticOperation.Addition || operation == ArithmeticOperation.Addition_UnsignedWithOverflowCheck))
{
verifiable = false;
return(rhs);
}
}
break;
// ECMA 335 III.1.5 Table 5: Integer Operations (and, div.un, or, rem.un, xor - 'not' excluded)
case ArithmeticOperation.BitwiseAnd:
case ArithmeticOperation.Division_Unsigned:
case ArithmeticOperation.BitwiseOr:
case ArithmeticOperation.Remainder_Unsigned:
case ArithmeticOperation.BitwiseXor:
if (lhs == rhs)
{
if (lhs.IsIntegerStackType())
{
return(lhs);
}
}
else
{
if ((lhs == DataType.Int32 && rhs == DataType.NativeInt) ||
(lhs == DataType.NativeInt && rhs == DataType.Int32))
{
return(DataType.NativeInt);
}
}
break;
// ECMA 335 III.1.5 Table 6: Shift Operations (shl, shr, shr.un)
case ArithmeticOperation.BitShiftLeft:
case ArithmeticOperation.BitShiftRight:
case ArithmeticOperation.BitShiftRight_Unsigned:
if (lhs.IsIntegerStackType() && (rhs == DataType.Int32 || rhs == DataType.NativeInt))
{
return(lhs);
}
break;
default:
throw new ArgumentException("Invalid arithmetic operation enumerant.", "operation");
}
verifiable = false;
return(null);
}