void ProcessExpressions(List <ILNode> body, ILBasicBlock head, int pos)
{
Stack <ILNode> stack = new Stack <ILNode>();
List <ILNode> list = new List <ILNode>();
Dup1Seen = false;
TestAndFixWierdLoop(body, head, pos);
for (int i = 0; i < head.Body.Count; i++)
{
if (stack.Count == 1 &&
head.MatchAt(i, GMCode.Dup) &&
head.MatchAt(i + 1, GMCode.Push) &&
head.MatchAt(i + 2, GMCode.Seq) &&
head.MatchAt(i + 3, GMCode.Bt))
{
CreateSwitchExpresion(stack.Pop(), list, body, head, pos);
break; // we are done with this block
}
else
{
Status s = ProcessExpression(list, head, i, stack);
}
}
head.Body = list;
}
void TestAndFixWierdLoop(List <ILNode> body, ILBasicBlock head, int pos)
{
object uvalue1;
ILValue value2;
ILLabel endLoop;
ILLabel startLoop;
ILExpression filler;
//Debug.Assert((head.Body[0] as ILLabel).Name != "L36");
// Wierd one here. I ran accross this a few times and I think this is generated code
// for events. Basicly, it pushes a constant on the stack and uses a repeat loop
// however since I am not doing ANY kind of real stack/temporary analysis. I would have
// to rewrite and add a bunch of code to get that to work and right now its only a few functions
// Its easyer to build a while loop out of it and let the decompiler handle it rather than
// build a more robust stack anilizer
// ugh have to make a new block for it too, meh
int headLen = head.Body.Count;
if (head.MatchAt(headLen - 6, GMCode.Push, out uvalue1) &&
head.MatchAt(headLen - 5, GMCode.Dup) &&
head.MatchAt(headLen - 4, GMCode.Push, out value2) &&
head.MatchAt(headLen - 3, GMCode.Sle) &&
head.MatchLastAndBr(GMCode.Bt, out endLoop, out filler, out startLoop))
{
// ok, lets rewrite the head so it makes sence
ILLabel newLoopStart = NewJunkLoop();
ILVariable genVar = NewGeneratedVar();
List <ILNode> newHead = new List <ILNode>();
for (int ii = 0; ii <= headLen - 7; ii++)
{
newHead.Add(head.Body[ii]); // add the front of it including the sub part
}
newHead.Add(new ILExpression(GMCode.Push, uvalue1));
newHead.Add(new ILExpression(GMCode.Pop, genVar));
newHead.Add(new ILExpression(GMCode.B, newLoopStart));
ILBasicBlock newLoopBlock = new ILBasicBlock();
newLoopBlock.Body.Add(newLoopStart);
newLoopBlock.Body.Add(new ILExpression(GMCode.Push, genVar));
newLoopBlock.Body.Add(new ILExpression(GMCode.Push, new ILValue(0)));
newLoopBlock.Body.Add(new ILExpression(GMCode.Sgt, null));
newLoopBlock.Body.Add(new ILExpression(GMCode.Bf, endLoop, new ILExpression(GMCode.Pop, null)));
newLoopBlock.Body.Add(new ILExpression(GMCode.B, startLoop));
head.Body = newHead;
body.Add(newLoopBlock);
// Now the hard part, we have to find the end bit
for (int j = pos; j < body.Count; j++)
{
ILBasicBlock bj = body[j] as ILBasicBlock;
ILLabel testEnd, testStart;
ILValue subPart;
int len = bj.Body.Count;
// Debug.Assert((bj.Body[0] as ILLabel).Name != "L114");
if (bj.MatchLastAndBr(GMCode.Bt, out testStart, out filler, out testEnd) &&
testEnd == endLoop && testStart == startLoop &&
bj.MatchAt(len - 3, GMCode.Dup) &&
bj.MatchAt(len - 4, GMCode.Sub) &&
bj.MatchAt(len - 5, GMCode.Push, out subPart)
)
{
List <ILNode> list2 = new List <ILNode>();
for (int ii = 0; ii <= len - 6; ii++)
{
list2.Add(bj.Body[ii]); // add the front of it including the sub part
}
list2.Add(new ILExpression(GMCode.Push, genVar));
list2.Add(bj.Body[len - 5]); // add the sub part
list2.Add(bj.Body[len - 4]); // add the sub part
list2.Add(new ILExpression(GMCode.Pop, genVar)); // assign it
list2.Add(new ILExpression(GMCode.B, newLoopStart)); // branch back to the start
bj.Body = list2; // replace
break; // all done, let it continue
}
}
// Debug.Assert(false); // coudln't find the end block
}
}
void CreateSwitchExpresion(ILNode condition, List <ILNode> list, List <ILNode> body, ILBasicBlock head, int pos)
{
// we are in a case block, check if its the first block
List <ILBasicBlock> caseBlocks = new List <ILBasicBlock>();
List <ILLabel> caseLabels = new List <ILLabel>();
ILExpression switchExpression = new ILExpression(GMCode.Switch, null);
switchExpression.Arguments.Add(NodeToExpresion(condition)); // pop the switch condition
ILBasicBlock current = head;
ILLabel nextCase;
ILLabel caseTrue;
ILExpression fakeArgument;
while (current.MatchLastAndBr(GMCode.Bt, out caseTrue, out fakeArgument, out nextCase))
{
ILNode operand;
if (!current.MatchAt(current.Body.Count - 4, GMCode.Push, out operand))
{
throw new Exception("fix");
}
if (!(operand is ILValue))
{
throw new Exception("Can only handle constants right now");
}
switchExpression.Arguments.Add(new ILExpression(GMCode.Case, caseTrue, NodeToExpresion(operand)));
caseLabels.Add(caseTrue);
body.Remove(current);
current = labelToBasicBlock[nextCase];
}
body.Insert(pos, head);
var lastBlock = current;
ILLabel fallLabel;
if (!lastBlock.MatchSingle(GMCode.B, out fallLabel))
{
throw new Exception("fix");
}
current = labelToBasicBlock[fallLabel];
if (!current.MatchAt(1, GMCode.Popz))
{ // has a default case
// Side note, the LoopAndConditions figures out if we have a default case by checking
// if the ending branch is linked to all the other case branches
// so we don't need to do anything here
// All this code is JUST for finding that popz that pops the condition out of the switch
// if you don't care about it, you could just search though all the expresions and remove any and all
// popz's I am beggining to think this is the right way to do it as I don't see any other uses
// of popz's
// Debug.Assert(false);
BuildNextBlockData(); // build block chain, we need this for default and mabye case lookups
// ok, this is why we DON'T want to remove redundent code as there is this empty
// useless goto RIGHt after this that has the link to the finale case
ILLabel nextBlockLabel = lastBlock.Body.First() as ILLabel;
var uselessBlock = this.labelToNextBlock[nextBlockLabel];
ILLabel newFallLabel;
if (!uselessBlock.MatchSingle(GMCode.B, out newFallLabel))
{
throw new Exception("fix");
}
current = labelToBasicBlock[newFallLabel];
if (!current.MatchAt(1, GMCode.Popz))
{
throw new Exception("I have no idea where the popz is for this switch");
}
}
current.Body.RemoveAt(1);
ILLabel lastBlockLabel = lastBlock.Body.First() as ILLabel;
if (this.labelGlobalRefCount[lastBlockLabel] == 1)
{
body.Remove(lastBlockLabel);
}
switchExpression.Operand = caseLabels.ToArray();
list.Add(switchExpression);
list.Add(new ILExpression(GMCode.B, fallLabel));
}