/// <summary>
/// Inserts phi functions for all variables in every block,
/// which contains 2 predesessors
/// </summary>
/// <param name="inputGraph"></param>
/// <returns></returns>
private CFGraph InsertPhiFunctions(CFGraph inputGraph)
{
CFGraph ssaGraph = inputGraph;
//HashSet<BaseBlock> blocksWithPhi = new HashSet<BaseBlock>();
foreach (var variable in variables)
{
foreach (var node in inputGraph.graph.Vertices)
{
if (node.ParentsNodes.Count >= 2)
{
IValue phiLabel = new IdentificatorValue("phi" + phiCounter);
var newAssign = new LinearRepresentation(Operation.Assign, variable
, phiLabel, null);
node.Value.AppendFirst(newAssign);
foreach (var parentNode in node.ParentsNodes)
{
var phiFunc = new LinearRepresentation(Operation.Phi, phiLabel as StringValue
, variable, parentNode.Value.Enumerate().Last().Label);
node.Value.InsertAfter(newAssign, phiFunc);
}
phiCounter++;
}
}
}
return(ssaGraph);
}
private void GenName(IdentificatorValue v)
{
if (variableStacks[v] == null)
{
variableStacks[v] = new Stack <int>();
}
var i = counters[v];
variableStacks[v].Push(i);
counters[v] = i + 1;
}
public void VisitBinOp(BinOp n)
{
var result = new LinearRepresentation(operatorToOperation(n.Op));
n.Lhs.AcceptVisit(this);
result.LeftOperand = idOrNum;
n.Rhs.AcceptVisit(this);
result.RightOperand = idOrNum;
var identificator = new IdentificatorValue(CONSTANT_PREFIX + valueCounter++.ToString());
idOrNum = identificator;
result.Destination = identificator;
evaluatedExpression.Add(result);
}
private bool isPhi(IdentificatorValue ident)
{
return(ident != null &&
ident.Value.Count() >= 3 &&
ident.Value.Substring(0, 3) == "phi");
}
private void Rename(CFGNode currentNode)
{
//Если уже посетили этот блок, выходим
if (visitedNodes.Contains(currentNode))
{
return;
}
foreach (var str in currentNode.Value.Enumerate())
{
//Если встретили фи-функцию, переименовываем ее левую часть
if (Utilities.IsPhiAssignment(str))
{
IdentificatorValue curVar = str.Destination as IdentificatorValue;
GenName(curVar);
int varCounter = variableStacks[curVar].Peek();
str.Destination = new IdentificatorValue(str.Destination.Value + varCounter.ToString());
}
//Переименовываем use переменные в правой части присваиваний
if (!Utilities.IsPhiIdentificator(str.LeftOperand as IdentificatorValue) && str.Operation != Operation.Phi)
{
if (str.RightOperand is IdentificatorValue)
{
IdentificatorValue curVar = str.RightOperand as IdentificatorValue;
int varCounter = variableStacks[curVar].Peek();
str.RightOperand = new IdentificatorValue(str.RightOperand.Value + varCounter.ToString());
}
if (str.LeftOperand is IdentificatorValue)
{
IdentificatorValue curVar = str.LeftOperand as IdentificatorValue;
int varCounter = variableStacks[curVar].Peek();
str.LeftOperand = new IdentificatorValue(str.LeftOperand.Value + varCounter.ToString());
}
if (str.Destination is IdentificatorValue)
{
IdentificatorValue curVar = str.Destination as IdentificatorValue;
GenName(curVar);
int varCounter = variableStacks[curVar].Peek();
str.Destination = new IdentificatorValue(str.Destination.Value + varCounter.ToString());
}
}
}
var children = new List <CFGNode>()
{
currentNode.directChild, currentNode.gotoNode
};
foreach (var child in children)
{
if (child == null)
{
continue;
}
foreach (var s in child.Value.Enumerate())
{
//Если встретили фи-функцию, переименовываем ее левую часть
if (Utilities.IsPhiAssignment(s))
{
//Ищем строку соответствующей фи-функции и переименовываем переменную в ее левой части
foreach (var line in child.Value.Enumerate()
.Select(str => str).Where(str => str.Operation == Operation.Phi && str.Destination == s.LeftOperand))
{
if (line.RightOperand == currentNode.Value.Enumerate().Last().Label)
{
IdentificatorValue curVar = line.LeftOperand as IdentificatorValue;
int varCounter = variableStacks[curVar].Peek();
line.LeftOperand = new IdentificatorValue(line.LeftOperand.Value + varCounter.ToString());
}
}
}
}
}
if (!visitedNodes.Contains(currentNode))
{
visitedNodes.Add(currentNode);
}
foreach (var child in children)
{
if (child != null)
{
Rename(child);
}
}
//Очищаем стек от переменных данного блока
foreach (var str in currentNode.Value.Enumerate())
{
if (str.LeftOperand is IdentificatorValue)
{
IdentificatorValue curVar = str.LeftOperand as IdentificatorValue;
if (variableStacks.Keys.Contains(curVar))
{
variableStacks[curVar].Pop();
}
}
}
}
public static bool IsPhiIdentificator(IdentificatorValue ident)
{
return(ident != null &&
ident.Value.Count() >= 3 &&
ident.Value.Substring(0, 3) == "phi");
}
