/// <summary>
/// Evaluate the type of a phi node.
/// </summary>
/// <param name="phi"></param>
internal static void EvaluatePhiType(Phi phi)
{
int allUnreached = 0;
Type typeSoFar = null;
bool first = true;
if (phi.Operands.Length == 0 || phi.DefinedBlock == null)
{
return;
}
foreach (var operand in phi.Operands)
{
var operandDetails = InternalVariablesDictionary[operand.Name];
if (operandDetails.Type == typeof(Undetermined))
{
typeSoFar = typeof(Undetermined);
break;
}
else
{
if (first)
{
first = false;
typeSoFar = operandDetails.Type;
if (typeSoFar == typeof(Unreached))
{
allUnreached += 1;
}
}
else
{
if (operandDetails.Type == typeof(Unreached))
{
allUnreached += 1;
}
else if (typeSoFar != operandDetails.Type)
{
typeSoFar = typeof(Undetermined);
break;
}
}
}
}
if (allUnreached == phi.Operands.Length)
{
typeSoFar = typeof(Unreached);
}
InternalVariablesDictionary[phi.Name].Type = typeSoFar;
return;
}
/// <summary>
/// Evaluate the constant value at a phi node
/// </summary>
/// <param name="phi"></param>
internal static void EvaluatePhiConstant(Phi phi)
{
int allUnreached = 0;
object constantSoFar = null;
bool first = true;
if (phi.Operands.Length == 0 || phi.DefinedBlock == null)
{
return;
}
foreach (var operand in phi.Operands)
{
var operandDetails = InternalVariablesDictionary[operand.Name];
if (operandDetails.Constant == Undetermined.UndeterminedConstant)
{
constantSoFar = Undetermined.UndeterminedConstant;
break;
}
else
{
if (first)
{
first = false;
constantSoFar = operandDetails.Constant;
if (constantSoFar == Unreached.UnreachedConstant)
{
allUnreached += 1;
}
}
else
{
if (operandDetails.Constant == Unreached.UnreachedConstant)
{
allUnreached += 1;
}
else if ((operandDetails.Constant == null && operandDetails.Constant != constantSoFar)
|| (operandDetails.Constant != null && !operandDetails.Constant.Equals(constantSoFar)))
{
constantSoFar = Undetermined.UndeterminedConstant;
break;
}
}
}
}
if (allUnreached == phi.Operands.Length)
{
constantSoFar = Unreached.UnreachedConstant;
}
InternalVariablesDictionary[phi.Name].Constant = constantSoFar;
return;
}