/// <summary>
/// Gets the nodes where the code graph is merging.
/// </summary>
/// <returns>The merge nodes.</returns>
public Dictionary <ProgramNode, MergeNodeType> GetMergeNodes()
{
Dictionary <ProgramNode, MergeNodeType> list = new Dictionary <ProgramNode, MergeNodeType>();
// look for diamond structures and loops in the code
// this is useful for fixing errors where the usage of the global variable is inside the if/else block
// but the solution needs a barrier outside the block
foreach (ProgramNode node in Graph.Nodes)
{
// identify merge points
if (node.Predecessors.Count > 1)
{
List <BackEdge> backEdges = Graph.BackEdges;
if (backEdges.Any(x => x.Destination == node))
{
// loop structures
BackEdge edge = backEdges.First(x => x.Destination == node);
List <ProgramNode> loopNodes = Graph.GetLoopNodes(edge);
if (loopNodes.Any(x => nodesContainingBarriers.Contains(x)))
{
list.Add(node, MergeNodeType.Loop);
}
}
else
{
// if-else diamond structures
// can be simplified by identifying the least common ancestor and inspecting if the intermediate nodes have barriers
ProgramNode lca = GetLCA(node.Predecessors);
if (lca != null)
{
List <ProgramNode> intermediateNodes = GetIntermediateNodes(lca, node);
if (intermediateNodes.Any(x => nodesContainingBarriers.Contains(x)))
{
if (!list.ContainsKey(lca))
{
list.Add(lca, MergeNodeType.IfElse);
}
}
}
}
}
}
return(list);
}
private void OnBackEdge([NotNull] TEdge edge)
{
Debug.Assert(edge != null);
BackEdge?.Invoke(edge);
}
protected void OnBackEdge(EdgeType edge)
{
BackEdge?.Invoke(edge);
}
/// <inheritdoc/> public void OnBackEdge(TGraph g, TEdge e) => BackEdge?.Invoke(g, e);