private void OptimizationInBlock(TacExpr expr, ThreeAddressCode block, string tmpName)
{
var taCode = block.TACodeLines.First;
while (taCode != null)
{
var node = taCode.Value;
if (node is TacAssignmentNode assign)
{
TacExpr nodeExpr = new TacExpr(assign.FirstOperand, assign.Operation, assign.SecondOperand);
string id = assign.LeftPartIdentifier;
if (id == expr.FirstOperand || id == expr.SecondOperand)
{
block.TACodeLines.AddAfter(block.TACodeLines.Find(node), expr.CreateAssignNode(tmpName));
}
if (nodeExpr.Equals(expr) && id != tmpName)
{
assign.FirstOperand = tmpName;
assign.Operation = null;
assign.SecondOperand = null;
}
}
taCode = taCode.Next;
}
}
public bool Optimize(ControlFlowGraph cfg)
{
bool isUsed = false;
var bb = cfg.SourceBasicBlocks;
for (int source = 0; source < bb.BasicBlockItems.Count(); source++)
{
var sourceBlock = bb.BasicBlockItems[source];
var sourceCodeLine = sourceBlock.TACodeLines.First;
while (sourceCodeLine != null)
{
var sourceNode = sourceCodeLine.Value;
if (sourceNode is TacAssignmentNode sourceAssign)
{
if (sourceAssign.SecondOperand == null)
{
break;
}
TacExpr sourceExpr = new TacExpr(sourceAssign.FirstOperand, sourceAssign.Operation, sourceAssign.SecondOperand);
for (int target = 0; target < bb.BasicBlockItems.Count(); target++)
{
var targetBlock = bb.BasicBlockItems[target];
var targetCodeLine = targetBlock.TACodeLines.First;
while (targetCodeLine != null)
{
var targetNode = targetCodeLine.Value;
if (targetNode == sourceNode)
{
break;
}
if (targetNode is TacAssignmentNode targetAssign)
{
string targetAssignId = targetAssign.LeftPartIdentifier;
bool isNeedAdditionaly = targetAssignId == sourceExpr.FirstOperand || targetAssignId == sourceExpr.SecondOperand;
TacExpr targetExpr = new TacExpr(targetAssign.FirstOperand, targetAssign.Operation, targetAssign.SecondOperand);
if (targetExpr.Equals(sourceExpr) || isNeedAdditionaly)
{
string tmpName = null;
HashSet <ThreeAddressCode> hashSet = null;
bool isIdVar = infoDictionary.ContainsKey(sourceExpr);
if (!isIdVar)
{
tmpName = TmpNameManager.Instance.GenerateTmpVariableName();
sourceBlock.TACodeLines.AddBefore(sourceBlock.TACodeLines.Find(sourceNode), sourceExpr.CreateAssignNode(tmpName));
OptimizationInBlock(sourceExpr, sourceBlock, tmpName);
hashSet = new HashSet <ThreeAddressCode>();
hashSet.Add(sourceBlock);
infoDictionary.Add(sourceExpr, new Tuple <string, HashSet <ThreeAddressCode> >(tmpName, hashSet));
}
else
{
if (!infoDictionary.ContainsKey(sourceExpr))
{
break;
}
var info = infoDictionary[sourceExpr];
tmpName = info.Item1;
hashSet = info.Item2;
}
if (sourceBlock == targetBlock)
{
break;
}
bool isOptim = hashSet.Contains(targetBlock);
if (!isOptim)
{
isUsed = true;
hashSet.Add(targetBlock);
OptimizationInBlock(sourceExpr, targetBlock, tmpName);
break;
}
}
}
targetCodeLine = targetCodeLine.Next;
}
}
}
sourceCodeLine = sourceCodeLine.Next;
}
}
return(isUsed);
}