public override void VisitFor(ForStatement forStatement)
{
Visit(forStatement.From);
Program.Add(new Assignment(forStatement.ForVariable.Name, ExpressionStack.Pop()));
var forBegin = NewLabel;
var forEnd = NewLabel;
var forVariable = new Identifier(forStatement.ForVariable.Name);
Visit(forStatement.To);
var forTo = ExpressionStack.Pop();
var check = new ConditionalGoto(
forEnd,
new BinaryOperation(forVariable, Operation.Greater, forTo))
{
Label = forBegin
};
Program.Add(check);
Visit(forStatement.Body);
Program.Add(Assignment.Increment(forVariable.Name));
Program.Add(new Goto(forBegin));
Program.Add(new NoOperation(forEnd));
}
protected bool Equals(ConditionalGoto other)
{
return(base.Equals(other) && Equals(Condition, other.Condition));
}
public List <ThreeAddressCommand> transformToThreeAddressCode()
{
var res = new List <ThreeAddressCommand>();
var done = new HashSet <BasicBlock>();
var stack = new Stack <BasicBlock>();
stack.Push(getBlockById(GetMinBlockId()));
BasicBlock cur = null;
while (done.Count < this.GetCount())
{
cur = stack.Pop();
done.Add(cur);
foreach (var c in cur.Commands)
{
res.Add(c);
}
switch (cur.OutputBlocks.Count)
{
case 0:
continue;
case 1:
BasicBlock outBlock = getBlockById(cur.OutputBlocks[0]);
if (!done.Contains(outBlock) && !stack.Contains(outBlock))
{
stack.Push(outBlock);
}
break;
case 2:
int lastStatementIndex = cur.Commands.Count - 1;
ConditionalGoto lastStatement = (ConditionalGoto)cur.Commands[lastStatementIndex];
BasicBlock outFirst = getBlockById(cur.OutputBlocks[0]);
BasicBlock outSecond = getBlockById(cur.OutputBlocks[1]);
string labelFirst = outFirst.Commands[0].Label;
string labelSecond = outSecond.Commands[0].Label;
string gotoLabel = lastStatement.GotoLabel;
if (gotoLabel == labelFirst)
{
BasicBlock t = outFirst;
outFirst = outSecond;
outSecond = t;
}
int firstLastIndex = outFirst.Commands.Count - 1;
ThreeAddressCommand secondLast = outFirst.Commands[firstLastIndex];
if ((secondLast is Goto) && !(secondLast is ConditionalGoto))
{
BasicBlock afterIfStatement = getBlockById(outFirst.OutputBlocks[0]);
if (!stack.Contains(afterIfStatement) && !done.Contains(afterIfStatement))
{
stack.Push(afterIfStatement);
}
}
if (!done.Contains(outSecond) && !stack.Contains(outSecond))
{
stack.Push(outSecond);
}
if (!done.Contains(outFirst) && !stack.Contains(outFirst))
{
stack.Push(outFirst);
}
break;
default:
throw new Exception("There cannot be more than two output blocks!");
}
}
return(res);
}
