public bool DetectSwitch_GenerateSwitch(IList <ILNode> body, ILBasicBlock head, int pos)
{
ILExpression condition;
ILLabel trueLabel;
ILLabel fallThough;
// REMEMBER: The searching goes backwards, so we find the FIRST case here, so here is the problem
// Evey time we run this, we have to search for the first block of the case statement backwards and if
// the push var is not resolved, we have to drop out... evey single time till the push IS resolved
// so be sure to run this at the bottom of the decision chain. Its fine if the push is a simple var
// but I can bet cash this runs 2-3 times if the push is some kind of expression like 5 + (3 % switch_var))
// we could change the way the optimizing loop works by going from the start and building a que of things
// to remove, delete or change hummm... Take longer but it would make building this functions MUCH simpler
if (MatchSwitchCase(head, out trueLabel, out fallThough, out condition) &&
!MatchSwitchCase(body.ElementAtOrDefault(pos - 1) as ILBasicBlock, out trueLabel, out fallThough, out condition)
) // && head.MatchLastAt(6, GMCode.Push,out switch_expr))
{
List <ILBasicBlock> caseBlocks = GetAllCaseBlocks(body, head, pos, out condition, out fallThough);
if (caseBlocks == null)
{
return(false);
}
ILExpression fswitch = new ILExpression(GMCode.Switch, null);
FakeSwitch args = new FakeSwitch();
args.SwitchExpression = condition;
args.CaseExpressions = caseBlocks.Select(bb =>
new KeyValuePair <ILExpression, ILLabel>((bb.ElementAtLast(3) as ILExpression).Arguments[0], (bb.ElementAtLast(1) as ILExpression).Operand as ILLabel)
).ToList();
fswitch.Operand = args;
// search the blocks for ending popz's and remove the popz
HashSet <ILBasicBlock> blocks_done = new HashSet <ILBasicBlock>();
Stack <ILBasicBlock> agenda = new Stack <ILBasicBlock>(caseBlocks);
while (agenda.Count > 0)
{
ILBasicBlock bb = agenda.Pop();
if (blocks_done.Contains(bb))
{
continue; // already did it
}
ILExpression popz = bb.Body.OfType <ILExpression>().Where(e => e.Code == GMCode.Popz).SingleOrDefault();
if (popz != null)
{
bb.Body.Remove(popz); // remove it
}
else
{
ILLabel exit = bb.OperandLabelLastAt(0);
if (exit != null && !blocks_done.Contains(labelToBasicBlock[exit]))
{
agenda.Push(labelToBasicBlock[exit]);
}
exit = bb.OperandLabelLastAt(1); // check if we have a bt or something
if (exit != null && !blocks_done.Contains(labelToBasicBlock[exit]))
{
agenda.Push(labelToBasicBlock[exit]);
}
}
blocks_done.Add(bb);
}
ILBasicBlock startOfAllCases = caseBlocks.First();
caseBlocks.Remove(startOfAllCases);
startOfAllCases.Body.RemoveTail(GMCode.Dup, GMCode.Push, GMCode.Seq, GMCode.Bt, GMCode.B);
startOfAllCases.Body.Add(fswitch);
startOfAllCases.Body.Add(new ILExpression(GMCode.B, fallThough)); // end_of_switch.EntryLabel()));
body.RemoveAll(caseBlocks);
return(true);
}
return(false);
}
public bool DetectSwitchAndConvertToBranches(IList <ILNode> body, ILBasicBlock head, int pos)
{
ILExpression condition;
ILLabel trueLabel;
ILLabel fallThough;
// REMEMBER: The searching goes backwards, so we find the LAST case here, so here is the problem
// Evey time we run this, we have to search for the first block of the case statement backwards and if
// the push var is not resolved, we have to drop out... evey single time till the push IS resolved
// so be sure to run this at the bottom of the decision chain. Its fine if the push is a simple var
// but I can bet cash this runs 2-3 times if the push is some kind of expression like 5 + (3 % switch_var))
// we could change the way the optimizing loop works by going from the start and building a que of things
// to remove, delete or change hummm... Take longer but it would make building this functions MUCH simpler
if (MatchSwitchCase(head, out trueLabel, out fallThough, out condition)) // && head.MatchLastAt(6, GMCode.Push,out switch_expr))
{
List <ILBasicBlock> caseBlocks = GetAllCaseBlocks(body, head, pos, out condition, out fallThough);
foreach (var bb in caseBlocks) // replace the dup statements
{
Debug.Assert(bb.MatchLastAt(5, GMCode.Dup));
bb.Body[bb.Body.Count - 5] = new ILExpression(GMCode.Push, null, condition);
ILExpression expr = bb.Body[bb.Body.Count - 3] as ILExpression;
// expr.Code = GMCode.Case; // conver the equals to a case
}
// search the blocks for ending popz's
HashSet <ILBasicBlock> blocks_done = new HashSet <ILBasicBlock>();
Stack <ILBasicBlock> agenda = new Stack <ILBasicBlock>(caseBlocks);
while (agenda.Count > 0)
{
ILBasicBlock bb = agenda.Pop();
if (blocks_done.Contains(bb))
{
continue; // already did it
}
ILExpression popz = bb.Body.OfType <ILExpression>().Where(e => e.Code == GMCode.Popz).SingleOrDefault();
if (popz != null)
{
bb.Body.Remove(popz); // remove it
blocks_done.Add(bb);
}
else
{
ILLabel exit = bb.OperandLabelLastAt(0);
if (exit != null && !blocks_done.Contains(labelToBasicBlock[exit]))
{
agenda.Push(labelToBasicBlock[exit]);
}
exit = bb.OperandLabelLastAt(1); // check if we have a bt or something
if (exit != null && !blocks_done.Contains(labelToBasicBlock[exit]))
{
agenda.Push(labelToBasicBlock[exit]);
}
}
}
return(true);
}
return(false);
}
