public IEnumerable <GraphBlock> ReverseVisitBlocks(GraphBlock start = null)
{
if (start == null)
{
start = Exit;
}
var visited = new HashSet <GraphBlock>();
var stack = new Stack <GraphBlock>();
stack.Push(start);
while (stack.Count > 0)
{
var b = stack.Pop();
if (visited.Contains(b))
{
continue;
}
yield return(b);
visited.Add(b);
foreach (var o in b.InBlocks)
{
stack.Push(o);
}
}
}
private GraphBlock CreateBlockAfter(GraphBlock before, string name)
{
var block = new GraphBlock(name);
before.ConnectTo(block);
return(block);
}
public Graph Build(JToken node)
{
_entry = new GraphBlock("entry");
_exit = new GraphBlock("exit");
_loopEntries = new List <GraphBlock>();
_loopExits = new List <GraphBlock>();
_exceptionHandlers = new List <List <GraphBlock> >();
_exceptionHandlers.Add(new List <GraphBlock>(new[] { _exit }));
var last = Build(node, _entry);
last.ConnectTo(_exit);
var graph = new Graph(_entry, _exit);
File.WriteAllText(@"..\..\graph0.dot", graph.GetDotString());
graph.CombineEmptyBlocks();
File.WriteAllText(@"..\..\graph.dot", graph.GetDotString());
graph.FillDominators();
graph.FillIDoms();
graph.FillDominantChildren();
graph.FillDominanceFrontiers();
File.WriteAllText(@"..\..\graph.txt", graph.GetGraphString());
return(graph);
}
public GraphBlock BuildIf(JToken node, GraphBlock current)
{
var id = current.Id;
current.AddNode(node);
var body = CreateBlockAfter(current, $"{id}:if_body");
body = Build(node["body"], body);
if (node["orelse"].Count() == 0)
{
var array = (JArray)node["orelse"];
array.Add(JToken.Parse("{ \"_Name\": \"Pass\" }"));
}
var orelse = CreateBlockAfter(current, $"{id}:if_orelse");
orelse = Build(node["orelse"], orelse);
var exit = new GraphBlock($"{id}:if_exit");
body.ConnectTo(exit);
orelse.ConnectTo(exit);
return(exit);
}
public GraphBlock BuildCall(JToken node, GraphBlock current)
{
current.AddNode(node);
foreach (var e in _exceptionHandlers.Last())
{
current.ConnectTo(e);
}
return(CreateBlockAfter(current, "next_to_call"));
}
public GraphBlock BuildRaise(JToken node, GraphBlock current)
{
current.AddNode(node);
foreach (var e in _exceptionHandlers.Last())
{
current.ConnectTo(e);
}
current.Exited = true;
return(current);
}
private void GetGraphString(GraphBlock block, int indent, StringBuilder result, HashSet <GraphBlock> visited)
{
if (visited.Contains(block))
{
return;
}
visited.Add(block);
result.Append(new string(' ', indent * 2));
result.AppendLine(block.ToString());
foreach (var b in block.OutBlocks)
{
GetGraphString(b, indent + 1, result, visited);
}
}
private GraphBlock Build(JToken nodes, GraphBlock current)
{
foreach (var n in nodes)
{
if (n.Type != JTokenType.Object)
{
throw new ArgumentException("Attempt to add non-object node");
}
var name = ObjectNameOf(n);
switch (name)
{
case "For": current = BuildFor(n, current); break;
case "While": current = BuildWhile(n, current); break;
case "If": current = BuildIf(n, current); break;
case "Raise": current = BuildRaise(n, current); break;
case "Try": current = BuildTry(n, current); break;
case "Break": current = BuildBreak(n, current); break;
case "Continue": current = BuildContinue(n, current); break;
case "Call": current = BuildCall(n, current); break;
default:
current.AddNode(n);
break;
}
if (current.Exited)
{
break;
}
}
return(current);
}
public GraphBlock BuildWhile(JToken node, GraphBlock current)
{
var id = current.Id;
var entry = CreateBlockAfter(current, $"{id}:while_entry");
entry.AddNode(node);
_loopEntries.Add(entry);
var body = CreateBlockAfter(entry, $"{id}:while_body");
var exit = new GraphBlock($"{id}:while_exit");
EnterLoop(entry, exit);
body = Build(node["body"], body);
ExitLoop();
body.ConnectTo(entry);
body.ConnectTo(exit);
return(exit);
}
public void FillDominanceFrontiers(GraphBlock block)
{
foreach (var b in block.OutBlocks)
{
if (b.IDom != block)
{
block.DominanceFrontiers.Add(b);
}
}
foreach (var b in block.DominantChildren)
{
FillDominanceFrontiers(b);
foreach (var df in b.DominanceFrontiers)
{
if (!df.Dominators.Contains(block))
{
block.DominanceFrontiers.Add(df);
}
}
}
}
public GraphBlock BuildTry(JToken node, GraphBlock current)
{
var id = current.Id;
var exit = new GraphBlock($"{id}:try_exit");
var handlers = new List <GraphBlock>();
foreach (var handler in node["handlers"])
{
var h = Build(handler["body"], new GraphBlock($"{id}:eh"));
h.ConnectTo(exit);
handlers.Add(h);
}
if (handlers.Count > 0)
{
_exceptionHandlers.Add(handlers);
}
if (node["finalbody"].Count() > 0)
{
throw new NotImplementedException("finally");
}
EnterTry(handlers);
var body = Build(node["body"], current);
ExitTry();
if (!body.Exited)
{
body.ConnectTo(exit);
return(exit);
}
return(null);
}
public Graph(GraphBlock entry, GraphBlock exit)
{
Entry = entry;
Exit = exit;
}
private void Exit(GraphBlock current)
{
current.ConnectTo(_exit);
current.Exited = true;
}
private void EnterLoop(GraphBlock entry, GraphBlock exit)
{
_loopEntries.Add(entry);
_loopExits.Add(exit);
}
public GraphBlock BuildContinue(JToken node, GraphBlock current)
{
current.AddNode(node);
Exit(_loopEntries.Last());
return(null);
}
public GraphBlock BuildBreak(JToken node, GraphBlock current)
{
current.AddNode(node);
Exit(_loopExits.Last());
return(null);
}
