private void CalculateInOut(ControlFlowGraph cfg, List <BasicBlock> blocks)
{
if (!Out.ContainsKey(cfg.start))
{
Out.Add(cfg.start, AvailableExpressionsTable.NewEmpty());
}
foreach (var block in blocks)
{
CreateGen(block);
CreateKill(block);
Out.Add(block, AvailableExpressionsTable.NewUniversal());
}
var changed = true;
while (changed)
{
changed = false;
foreach (var block in blocks)
{
var prevOuts = new List <AvailableExpressionsTable>();
foreach (var prev in block.In)
{
prevOuts.Add(Out[prev]);
}
In[block] = AvailableExpressionsTable.Intersection(prevOuts);
var oldOut = Out[block];
Out[block] = CalculateOut(In[block], block);
if (!oldOut.Equals(Out[block]))
{
changed = true;
}
}
}
}
public static AvailableExpressionsTable NewEmpty()
{
var res = new AvailableExpressionsTable();
res.IsEmpty = true;
return(res);
}
public static AvailableExpressionsTable NewUniversal()
{
var res = new AvailableExpressionsTable();
res.IsUniversal = true;
return(res);
}
public AvailableExpressionsTable CalculateOut(AvailableExpressionsTable inTable, BasicBlock block)
{
var newTable = inTable.Copy();
var kill = kills[block];
foreach (var killVariable in kill.KillVariables)
{
newTable.RemoveExpressions(killVariable);
}
newTable.AddExpressions(kill.GenExpressions, kill.GenInstructions);
return(newTable);
}
