/// <summary>
/// Group input into a set of blocks that can be later arbitraliby schufled.
/// The method adds necessary branches to make control flow between blocks
/// explicit and thus order independent.
/// </summary>
void SplitToMovableBlocks(ILBlock block)
{
// Remve no-ops
// TODO: Assign the no-op range to someting
block.Body = block.Body.Where(n => !(n is ILExpression && ((ILExpression)n).OpCode == OpCodes.Nop)).ToList();
List<ILNode> moveableBlocks = new List<ILNode>();
ILMoveableBlock moveableBlock = new ILMoveableBlock() { OriginalOrder = (nextBlockIndex++) };
moveableBlocks.Add(moveableBlock);
block.EntryPoint = new ILLabel() { Name = "Block_" + moveableBlock.OriginalOrder };
moveableBlock.Body.Add(block.EntryPoint);
if (block.Body.Count > 0) {
moveableBlock.Body.Add(block.Body[0]);
for (int i = 1; i < block.Body.Count; i++) {
ILNode lastNode = block.Body[i - 1];
ILNode currNode = block.Body[i];
// Insert split
if ((currNode is ILLabel && !(lastNode is ILLabel)) ||
lastNode is ILTryCatchBlock ||
currNode is ILTryCatchBlock ||
(lastNode is ILExpression) && ((ILExpression)lastNode).OpCode.IsBranch() ||
(currNode is ILExpression) && ((ILExpression)currNode).OpCode.IsBranch())
{
ILBlock lastBlock = moveableBlock;
moveableBlock = new ILMoveableBlock() { OriginalOrder = (nextBlockIndex++) };
moveableBlocks.Add(moveableBlock);
// Explicit branch from one block to other
// (unless the last expression was unconditional branch)
if (!(lastNode is ILExpression) || ((ILExpression)lastNode).OpCode.CanFallThough()) {
ILLabel blockLabel = new ILLabel() { Name = "Block_" + moveableBlock.OriginalOrder };
lastBlock.Body.Add(new ILExpression(OpCodes.Br, blockLabel));
moveableBlock.Body.Add(blockLabel);
}
}
moveableBlock.Body.Add(currNode);
}
}
block.Body = moveableBlocks;
return;
}
/*
public enum ShortCircuitOperator
{
LeftAndRight,
LeftOrRight,
NotLeftAndRight,
NotLeftOrRight,
}
static bool TryOptimizeShortCircuit(Node head)
{
if ((head is BasicBlock) &&
(head as BasicBlock).BranchBasicBlock != null &&
(head as BasicBlock).FallThroughBasicBlock != null) {
head.Parent.MergeChilds<SimpleBranch>(head);
return true;
}
Branch top = head as Branch;
if (top == null) return false;
Branch left = head.FloatUpToNeighbours(top.TrueSuccessor) as Branch;
Branch right = head.FloatUpToNeighbours(top.FalseSuccessor) as Branch;
// A & B
if (left != null &&
left.Predecessors.Count == 1 &&
left.FalseSuccessor == top.FalseSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, left);
scBranch.Operator = ShortCircuitOperator.LeftAndRight;
return true;
}
// ~A | B
if (left != null &&
left.Predecessors.Count == 1 &&
left.TrueSuccessor == top.FalseSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, left);
scBranch.Operator = ShortCircuitOperator.NotLeftOrRight;
return true;
}
// A | B
if (right != null &&
right.Predecessors.Count == 1 &&
right.TrueSuccessor == top.TrueSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, right);
scBranch.Operator = ShortCircuitOperator.LeftOrRight;
return true;
}
// ~A & B
if (right != null &&
right.Predecessors.Count == 1 &&
right.FalseSuccessor == top.TrueSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, right);
scBranch.Operator = ShortCircuitOperator.NotLeftAndRight;
return true;
}
return false;
}
*/
void OrderNodes(ILBlock ast)
{
// Order movable nodes
var blocks = ast.GetSelfAndChildrenRecursive<ILBlock>().Where(b => !(b is ILMoveableBlock)).ToList();
ILMoveableBlock first = new ILMoveableBlock() { OriginalOrder = -1 };
foreach(ILBlock block in blocks) {
block.Body = block.Body.OrderBy(n => (n.GetSelfAndChildrenRecursive<ILMoveableBlock>().FirstOrDefault() ?? first).OriginalOrder).ToList();
}
}
