public override void OptimizeOperations(CilMethodInterpreter interpreter)
{
_operations = interpreter.MidRepresentation.LocalOperations.ToArray();
_labelTable = interpreter.MidRepresentation.UseDef.GetLabelTable();
_pointsOfAnalysis = new DfaPointOfAnalysis[_operations.Length + 1];
var startingConclusions = new DfaPointOfAnalysis();
Interpret(0, startingConclusions);
ApplyResult();
}
public bool Equals(DfaPointOfAnalysis other)
{
if (ReferenceEquals(null, other))
{
return(false);
}
if (ReferenceEquals(this, other))
{
return(true);
}
return(Compare(other));
}
private bool Compare(DfaPointOfAnalysis other)
{
if (States.Count != other.States.Count)
{
return(false);
}
foreach (var variableState in States)
{
VariableState result;
if (!other.States.TryGetValue(variableState.Key, out result))
{
return(false);
}
if (!result.Compare(variableState.Value))
{
return(false);
}
}
return(true);
}
public DfaPointOfAnalysis Merge(DfaPointOfAnalysis pointsOfAnalysis)
{
var result = new DfaPointOfAnalysis();
var combinedList = new List <Tuple <LocalVariable, VariableState> >();
foreach (var variableState in States)
{
combinedList.Add(new Tuple <LocalVariable, VariableState>(variableState.Key, variableState.Value));
}
if (pointsOfAnalysis != null)
{
foreach (var variableState in pointsOfAnalysis.States)
{
combinedList.Add(new Tuple <LocalVariable, VariableState>(variableState.Key, variableState.Value));
}
}
foreach (var tuple in combinedList)
{
VariableState variableState;
if (result.States.TryGetValue(tuple.Item1, out variableState))
{
if (!tuple.Item2.Equals(variableState))
{
result.States[tuple.Item1] = new VariableState
{
State = VariableState.ConstantState.NotConstant
};
}
}
else
{
result.States[tuple.Item1] = tuple.Item2;
}
}
return(result);
}
private void Interpret(int cursor, DfaPointOfAnalysis startingConclusions)
{
var canUpdate = true;
if (startingConclusions.Equals(_pointsOfAnalysis[cursor]))
{
return;
}
while (canUpdate)
{
_pointsOfAnalysis[cursor] = startingConclusions.Merge(_pointsOfAnalysis[cursor]);
var operation = GetOperation(cursor);
var analysis = _pointsOfAnalysis[cursor];
Assignment assignment;
switch (operation.Kind)
{
case OperationKind.Assignment:
assignment = operation.GetAssignment();
var constant = assignment.Right as ConstValue;
if (constant != null)
{
analysis.States[assignment.AssignedTo] = new VariableState
{
Constant = constant,
State = VariableState.ConstantState.Constant
};
}
else
{
analysis.States[assignment.AssignedTo] = new VariableState
{
State = VariableState.ConstantState.NotConstant
};
}
startingConclusions = analysis;
break;
case OperationKind.BinaryOperator:
assignment = (Assignment)operation;
analysis.States[assignment.AssignedTo] = new VariableState
{
State = VariableState.ConstantState.NotConstant
};
break;
case OperationKind.BranchOperator:
var branchOperator = (BranchOperator)operation;
Interpret(JumpTo(branchOperator.JumpTo), analysis);
break;
case OperationKind.Label:
break;
case OperationKind.Call:
break;
case OperationKind.Return:
return;
case OperationKind.AlwaysBranch:
var jumpTo = ((AlwaysBranch)operation).JumpTo;
Interpret(JumpTo(jumpTo), analysis);
return;
default:
throw new InvalidOperationException(String.Format("Unhandled: {0}", operation));
}
cursor++;
canUpdate = !(startingConclusions.Equals(_pointsOfAnalysis[cursor]));
}
}