public void InheritSourceConflicts(NodeIndex newNode, NodeIndex oldNode)
{
foreach (EdgeIndex edge in graph.EdgesInto(oldNode).ToArray())
{
int source = graph.SourceOf(edge);
EdgeIndex edge2 = graph.AddEdge(source, newNode);
prohibitedLoopVars[edge2] = prohibitedLoopVars[edge];
offsetInfos[edge2] = offsetInfos[edge];
}
}
/// <summary>
/// Analyse equality constraints, which appear as static method calls to Constrain.Equal
/// </summary>
/// <param name="imie"></param>
/// <returns></returns>
protected override IExpression ConvertMethodInvoke(IMethodInvokeExpression imie)
{
// If this is a constrain equal, then we will add the equality to the equality map.
if (Recognizer.IsStaticGenericMethod(imie, new Action <PlaceHolder, PlaceHolder>(Constrain.Equal <PlaceHolder>)))
{
int node0 = CreateNodeAndEdges(imie.Arguments[0]);
int node1 = CreateNodeAndEdges(imie.Arguments[1]);
graph.AddEdge(node0, node1);
graph.AddEdge(node1, node0);
}
return(base.ConvertMethodInvoke(imie));
}
public void IndexedGraphTest()
{
IndexedGraph g = new IndexedGraph();
int a = g.AddNode();
int b = g.AddNode();
int c = g.AddNode();
int ab = g.AddEdge(a, b);
int bb = g.AddEdge(b, b); // self loop
int bc = g.AddEdge(b, c);
int bc2 = g.AddEdge(b, c); // double edge
Assert.Equal(c, g.TargetOf(bc));
Assert.Equal(bb, g.GetEdge(b, b));
Assert.Equal(0, g.EdgeCount(a, c));
Assert.Equal(2, g.EdgeCount(b, c));
Assert.Equal(4, g.EdgeCount());
Assert.Equal(1, g.NeighborCount(a));
Assert.Equal(2, g.NeighborCount(c));
Assert.Equal(1, g.TargetCount(a));
Assert.Equal(0, g.SourceCount(a));
Console.Write("EdgesOf(b):");
foreach (int edge in g.EdgesOf(b))
{
Console.Write(" {0}", edge);
}
Console.WriteLine();
Console.Write("EdgesInto(b):");
foreach (int edge in g.EdgesInto(b))
{
Console.Write(" {0}", edge);
}
Console.WriteLine();
Console.Write("EdgesOutOf(b):");
foreach (int edge in g.EdgesOutOf(b))
{
Console.Write(" {0}", edge);
}
Console.WriteLine();
Console.Write("EdgesLinking(b,c):");
foreach (int edge in g.EdgesLinking(b, c))
{
Console.Write(" {0}", edge);
}
Console.WriteLine();
}
protected override IExpression ConvertMethodInvoke(IMethodInvokeExpression imie)
{
if (imie.Method.Target is IThisReferenceExpression)
{
IMethodDeclaration imd = context.FindAncestor <IMethodDeclaration>();
int sourceMethod = GetMethodIndex(imd);
int targetMethod = GetMethodIndex(imie.Method.Method);
MethodGraph.AddEdge(sourceMethod, targetMethod);
//Trace.WriteLine($"{sourceMethod} {methods[sourceMethod].Name} called {targetMethod} {methods[targetMethod].Name}");
}
return(base.ConvertMethodInvoke(imie));
}
public void GroupGraphTest()
{
IndexedGraph g = new IndexedGraph(2);
g.AddEdge(1, 0);
int[] groupOf = new int[] { -1, 2, -1 };
GroupGraph groupGraph = new GroupGraph(g, groupOf, g.Nodes.Count);
groupGraph.BuildGroupEdges();
var schedule = groupGraph.GetScheduleWithGroups(groupGraph.SourcesOf);
Assert.True(schedule[0] == 1);
Assert.True(schedule[1] == 0);
}
public DependencyGraph2(BasicTransformContext context,
IEnumerable <IStatement> inputs,
BackEdgeHandling backEdgeHandling,
Action <IWhileStatement> beginWhile,
Action <IWhileStatement> endWhile,
Action <IConditionStatement> beginFirstIterPost,
Action <IConditionStatement> endFirstIterPost,
Action <IStatement, NodeIndex> action)
{
Set <NodeIndex> nodesInCurrentWhile = new Set <EdgeIndex>();
int whileDepth = 0;
// create a dependency graph where while loops are flattened (the while loops themselves are not nodes)
// the graph will only contain read-after-write and write-after-alloc dependencies for now
// add write-after-read dependencies
isWriteAfterRead = dependencyGraph.CreateEdgeData(false);
DeadCodeTransform.ForEachStatement(inputs,
delegate(IWhileStatement iws)
{
beginWhile(iws);
nodesInCurrentWhile.Clear();
whileDepth++;
},
delegate(IWhileStatement iws)
{
// all duplicates in a while loop should share all targets
foreach (KeyValuePair <IStatement, Set <NodeIndex> > entry in duplicates)
{
IStatement ist = entry.Key;
Set <NodeIndex> set = entry.Value;
Set <NodeIndex> targets = new Set <EdgeIndex>();
// collect all targets in the while loop
foreach (NodeIndex node in set)
{
foreach (NodeIndex target in dependencyGraph.TargetsOf(node))
{
if (nodesInCurrentWhile.Contains(target))
{
targets.Add(target);
}
}
}
Set <NodeIndex> backEdgeTargets = null;
if (!backEdges.TryGetValue(ist, out backEdgeTargets))
{
backEdgeTargets = new Set <EdgeIndex>();
backEdges[ist] = backEdgeTargets;
}
// add all targets to all duplicates in the loop
foreach (NodeIndex node in set)
{
if (!nodesInCurrentWhile.Contains(node))
{
continue;
}
foreach (NodeIndex target in targets)
{
if (!dependencyGraph.ContainsEdge(node, target))
{
if (backEdgeHandling == BackEdgeHandling.Include)
{
dependencyGraph.AddEdge(node, target);
}
else if (backEdgeHandling == BackEdgeHandling.Reverse)
{
if (!dependencyGraph.ContainsEdge(target, node))
{
dependencyGraph.AddEdge(target, node);
}
}
if (target < node)
{
if (backEdgeTargets == null && !backEdges.TryGetValue(ist, out backEdgeTargets))
{
backEdgeTargets = new Set <EdgeIndex>();
backEdges[ist] = backEdgeTargets;
}
backEdgeTargets.Add(target);
}
}
}
}
}
endWhile(iws);
whileDepth--;
},
beginFirstIterPost,
endFirstIterPost,
delegate(IStatement ist)
{
DependencyInformation di = context.InputAttributes.Get <DependencyInformation>(ist);
if (di == null)
{
context.Error("Dependency information not found for statement: " + ist);
di = new DependencyInformation();
}
NodeIndex targetIndex = dependencyGraph.AddNode();
Set <NodeIndex> backEdgeTargets;
Set <NodeIndex> sources = new Set <NodeIndex>(); // for fast checking of duplicate sources
foreach (IStatement source in
di.GetDependenciesOfType(DependencyType.Dependency | DependencyType.Declaration))
{
int sourceIndex;
// we assume that the statements are already ordered properly to respect dependencies.
// if the source is not in indexOfNode, then it must be a cyclic dependency in this while loop.
if (indexOfNode.TryGetValue(source, out sourceIndex))
{
if (!sources.Contains(sourceIndex))
{
sources.Add(sourceIndex);
EdgeIndex edge = dependencyGraph.AddEdge(sourceIndex, targetIndex);
}
}
else
{
sourceIndex = -1;
}
if (sourceIndex == -1)
{
// add a back edge
if (!backEdges.TryGetValue(source, out backEdgeTargets))
{
backEdgeTargets = new Set <EdgeIndex>();
backEdges[source] = backEdgeTargets;
}
backEdgeTargets.Add(targetIndex);
// add a dependency on the initializers of source
Stack <IStatement> todo = new Stack <IStatement>();
todo.Push(source);
while (todo.Count > 0)
{
IStatement source2 = todo.Pop();
DependencyInformation di2 = context.InputAttributes.Get <DependencyInformation>(source2);
if (di2 == null)
{
context.Error("Dependency information not found for statement: " + source2);
continue;
}
foreach (IStatement init in di2.Overwrites)
{
int initIndex;
if (indexOfNode.TryGetValue(init, out initIndex))
{
if (!sources.Contains(initIndex))
{
sources.Add(initIndex);
EdgeIndex edge = dependencyGraph.AddEdge(initIndex, targetIndex);
}
}
else
{
todo.Push(init);
}
}
}
}
}
if (indexOfNode.ContainsKey(ist))
{
Set <int> set;
if (!duplicates.TryGetValue(ist, out set))
{
set = new Set <int>();
duplicates[ist] = set;
set.Add(indexOfNode[ist]);
}
set.Add(targetIndex);
}
// the same statement may appear multiple times. when looking up indexOfNode, we want to use the last occurrence of the statement.
indexOfNode[ist] = targetIndex; // must do this at the end, in case the stmt depends on a previous occurrence of itself
nodesInCurrentWhile.Add(targetIndex);
nodes.Add(ist);
if (backEdgeHandling != BackEdgeHandling.Ignore && backEdges.TryGetValue(ist, out backEdgeTargets))
{
// now that ist has an index, we can fill in the back edges
foreach (NodeIndex node in backEdgeTargets)
{
if (backEdgeHandling == BackEdgeHandling.Include)
{
if (dependencyGraph.ContainsEdge(targetIndex, node))
{
throw new Exception("Internal: back edge already present");
}
dependencyGraph.AddEdge(targetIndex, node);
}
else
{
// make a new edge, even if one exists.
EdgeIndex edge = dependencyGraph.AddEdge(node, targetIndex);
isWriteAfterRead[edge] = true;
}
}
}
action(ist, targetIndex);
});
if (string.Empty.Length > 0)
{
// loop statements in their original order
foreach (NodeIndex target in dependencyGraph.Nodes)
{
IStatement ist = nodes[target];
if (ist is IWhileStatement)
{
continue;
}
foreach (NodeIndex source in GetPreviousReaders(context, dependencyGraph, target, nodes, indexOfNode).ToReadOnlyList())
{
if (source > target)
{
throw new Exception("Internal: source statement follows target");
}
// make a new edge, even if one exists.
EdgeIndex edge = dependencyGraph.AddEdge(source, target);
isWriteAfterRead[edge] = true;
}
}
}
isWriteAfterWrite = dependencyGraph.CreateEdgeData(false);
// loop statements in their original order
foreach (NodeIndex target in dependencyGraph.Nodes)
{
IStatement ist = nodes[target];
if (ist is IWhileStatement)
{
continue;
}
foreach (NodeIndex source in GetOverwrites(context, dependencyGraph, target, nodes, indexOfNode).ToReadOnlyList())
{
if (source > target)
{
throw new Exception("Internal: source statement follows target");
}
if (dependencyGraph.ContainsEdge(source, target))
{
foreach (EdgeIndex edge in dependencyGraph.EdgesLinking(source, target))
{
isWriteAfterWrite[edge] = true;
}
}
else
{
EdgeIndex edge = dependencyGraph.AddEdge(source, target);
isWriteAfterWrite[edge] = true;
}
}
}
dependencyGraph.NodeCountIsConstant = true;
dependencyGraph.IsReadOnly = true;
for (int targetIndex = 0; targetIndex < dependencyGraph.Nodes.Count; targetIndex++)
{
IStatement ist = nodes[targetIndex];
DependencyInformation di = context.InputAttributes.Get <DependencyInformation>(ist);
if (di == null)
{
continue;
}
if (di.IsOutput)
{
outputNodes.Add(targetIndex);
}
}
}
protected override void DoConvertMethodBody(IList <IStatement> outputs, IList <IStatement> inputs)
{
List <int> whileNumberOfNode = new List <int>();
List <int> fusedCountOfNode = new List <int>();
List <List <IStatement> > containersOfNode = new List <List <IStatement> >();
// the code may have multiple while(true) loops, however these must be disjoint.
// therefore we treat 'while' as one container, but give each loop a different 'while number'.
int outerWhileCount = 0;
int currentOuterWhileNumber = 0;
int currentFusedCount = 0;
List <Set <IVariableDeclaration> > loopVarsOfWhileNumber = new List <Set <IVariableDeclaration> >();
// build the dependency graph
var g = new DependencyGraph2(context, inputs, DependencyGraph2.BackEdgeHandling.Ignore,
delegate(IWhileStatement iws)
{
if (iws is IFusedBlockStatement)
{
if (iws.Condition is IVariableReferenceExpression)
{
currentFusedCount++;
}
}
else
{
outerWhileCount++;
currentOuterWhileNumber = outerWhileCount;
}
},
delegate(IWhileStatement iws)
{
if (iws is IFusedBlockStatement)
{
if (iws.Condition is IVariableReferenceExpression)
{
currentFusedCount--;
}
}
else
{
currentOuterWhileNumber = 0;
}
},
delegate(IConditionStatement ics)
{
},
delegate(IConditionStatement ics)
{
},
delegate(IStatement ist, int targetIndex)
{
int whileNumber = currentOuterWhileNumber;
whileNumberOfNode.Add(whileNumber);
fusedCountOfNode.Add(currentFusedCount);
List <IStatement> containers = new List <IStatement>();
LoopMergingTransform.UnwrapStatement(ist, containers);
containersOfNode.Add(containers);
for (int i = 0; i < currentFusedCount; i++)
{
if (containers[i] is IForStatement ifs)
{
var loopVar = Recognizer.LoopVariable(ifs);
if (loopVarsOfWhileNumber.Count <= whileNumber)
{
while (loopVarsOfWhileNumber.Count <= whileNumber)
{
loopVarsOfWhileNumber.Add(new Set <IVariableDeclaration>());
}
}
Set <IVariableDeclaration> loopVars = loopVarsOfWhileNumber[whileNumber];
loopVars.Add(loopVar);
}
}
});
var nodes = g.nodes;
var dependencyGraph = g.dependencyGraph;
for (int whileNumber = 1; whileNumber < loopVarsOfWhileNumber.Count; whileNumber++)
{
foreach (var loopVar in loopVarsOfWhileNumber[whileNumber])
{
// Any statement (in the while loop) that has a forward descendant and a backward descendant will be cloned, so we want to minimize the number of such nodes.
// The free variables in this problem are the loop directions at the leaf statements, since all other loop directions are forced by these.
// We find the optimal labeling of the free variables by solving a min cut problem on a special network.
// The network is constructed so that the cost of a cut is equal to the number of statements that will be cloned.
// The network has 2 nodes for every statement: an in-node and an out-node.
// For a non-leaf statement, there is a capacity 1 edge from the in-node to out-node. This edge is cut when the statement is cloned.
// For a leaf statement, there is an infinite capacity edge in both directions, or equivalently a single node.
// If statement A depends on statement B, then there is an infinite capacity edge from in-A to in-B, and from out-B to out-A,
// representing the fact that cloning A requires cloning B, but not the reverse.
// If a statement must appear with a forward loop, it is connected to the source.
// If a statement must appear with a backward loop, it is connected to the sink.
// construct a capacitated graph
int inNodeStart = 0;
int outNodeStart = inNodeStart + dependencyGraph.Nodes.Count;
int sourceNode = outNodeStart + dependencyGraph.Nodes.Count;
int sinkNode = sourceNode + 1;
int cutNodeCount = sinkNode + 1;
Func <NodeIndex, int> getInNode = node => node + inNodeStart;
Func <NodeIndex, int> getOutNode = node => node + outNodeStart;
IndexedGraph network = new IndexedGraph(cutNodeCount);
const float infinity = 1000000f;
List <float> capacity = new List <float>();
List <NodeIndex> nodesOfInterest = new List <NodeIndex>();
foreach (var node in dependencyGraph.Nodes)
{
if (whileNumberOfNode[node] != whileNumber)
{
continue;
}
NodeIndex source = node;
List <IStatement> containersOfSource = containersOfNode[source];
bool hasLoopVar = containersOfSource.Any(container => container is IForStatement && Recognizer.LoopVariable((IForStatement)container) == loopVar);
if (!hasLoopVar)
{
continue;
}
nodesOfInterest.Add(node);
IStatement sourceSt = nodes[source];
var readAfterWriteEdges = dependencyGraph.EdgesOutOf(source).Where(edge => !g.isWriteAfterRead[edge]);
bool isLeaf = true;
int inNode = getInNode(node);
int outNode = getOutNode(node);
foreach (var target in readAfterWriteEdges.Select(dependencyGraph.TargetOf))
{
List <IStatement> containersOfTarget = containersOfNode[target];
IStatement targetSt = nodes[target];
ForEachMatchingLoopVariable(containersOfSource, containersOfTarget, (loopVar2, afs, bfs) =>
{
if (loopVar2 == loopVar)
{
int inTarget = getInNode(target);
int outTarget = getOutNode(target);
network.AddEdge(inTarget, inNode);
capacity.Add(infinity);
network.AddEdge(outNode, outTarget);
capacity.Add(infinity);
isLeaf = false;
}
});
}
if (isLeaf)
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} leaf {sourceSt}");
}
network.AddEdge(inNode, outNode);
capacity.Add(infinity);
network.AddEdge(outNode, inNode);
capacity.Add(infinity);
}
else
{
network.AddEdge(inNode, outNode);
capacity.Add(1f);
}
int fusedCount = fusedCountOfNode[node];
Direction desiredDirectionOfSource = GetDesiredDirection(loopVar, containersOfSource, fusedCount);
if (desiredDirectionOfSource == Direction.Forward)
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} forward {sourceSt}");
}
network.AddEdge(sourceNode, inNode);
capacity.Add(infinity);
}
else if (desiredDirectionOfSource == Direction.Backward)
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} backward {sourceSt}");
}
network.AddEdge(outNode, sinkNode);
capacity.Add(infinity);
}
}
network.IsReadOnly = true;
// compute the min cut
MinCut <NodeIndex, EdgeIndex> mc = new MinCut <EdgeIndex, EdgeIndex>(network, e => capacity[e]);
mc.Sources.Add(sourceNode);
mc.Sinks.Add(sinkNode);
Set <NodeIndex> sourceGroup = mc.GetSourceGroup();
foreach (NodeIndex node in nodesOfInterest)
{
IStatement sourceSt = nodes[node];
bool forwardIn = sourceGroup.Contains(getInNode(node));
bool forwardOut = sourceGroup.Contains(getOutNode(node));
if (forwardIn != forwardOut)
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} will clone {sourceSt}");
}
}
else if (forwardIn)
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} wants forward {sourceSt}");
}
}
else
{
if (debug)
{
log.Add($"loopVar={loopVar.Name} wants backward {sourceSt}");
}
var containers = containersOfNode[node];
bool isForwardLoop = true;
foreach (var container in containers)
{
if (container is IForStatement)
{
IForStatement ifs = (IForStatement)container;
if (Recognizer.LoopVariable(ifs) == loopVar)
{
isForwardLoop = Recognizer.IsForwardLoop(ifs);
}
}
}
if (isForwardLoop)
{
Set <IVariableDeclaration> loopVarsToReverse;
if (!loopVarsToReverseInStatement.TryGetValue(sourceSt, out loopVarsToReverse))
{
// TODO: re-use equivalent sets
loopVarsToReverse = new Set <IVariableDeclaration>();
loopVarsToReverseInStatement.Add(sourceSt, loopVarsToReverse);
}
loopVarsToReverse.Add(loopVar);
}
}
}
}
}
base.DoConvertMethodBody(outputs, inputs);
}
#pragma warning restore 162
#endif
private void PostProcess()
{
// create a dependency graph between MethodInvokes
Dictionary <IVariableDeclaration, List <int> > mutationsOfVariable = new Dictionary <IVariableDeclaration, List <NodeIndex> >();
IndexedGraph g = new IndexedGraph(factorExprs.Count);
foreach (NodeIndex node in g.Nodes)
{
IExpression factor = factorExprs[node];
NodeInfo info = GetNodeInfo(factor);
for (int i = 0; i < info.arguments.Count; i++)
{
if (info.isReturnOrOut[i])
{
// this is a mutation. add to mutationsOfVariable.
IVariableDeclaration ivd = Recognizer.GetVariableDeclaration(info.arguments[i]);
if (ivd != null && CodeRecognizer.IsStochastic(context, ivd))
{
List <int> nodes;
if (!mutationsOfVariable.TryGetValue(ivd, out nodes))
{
nodes = new List <NodeIndex>();
mutationsOfVariable[ivd] = nodes;
}
nodes.Add(node);
}
}
}
}
foreach (NodeIndex node in g.Nodes)
{
IExpression factor = factorExprs[node];
NodeInfo info = GetNodeInfo(factor);
for (int i = 0; i < info.arguments.Count; i++)
{
if (!info.isReturnOrOut[i])
{
// not a mutation. create a dependency on all mutations.
IVariableDeclaration ivd = Recognizer.GetVariableDeclaration(info.arguments[i]);
if (ivd != null && CodeRecognizer.IsStochastic(context, ivd))
{
foreach (NodeIndex source in mutationsOfVariable[ivd])
{
g.AddEdge(source, node);
}
}
}
}
}
List <NodeIndex> topo_nodes = new List <NodeIndex>();
DepthFirstSearch <NodeIndex> dfs = new DepthFirstSearch <NodeIndex>(g.SourcesOf, g);
dfs.FinishNode += delegate(NodeIndex node)
{
IExpression factor = factorExprs[node];
ProcessFactor(factor, MessageDirection.Forwards);
topo_nodes.Add(node);
};
// process nodes forward
dfs.SearchFrom(g.Nodes);
// process nodes backward
for (int i = topo_nodes.Count - 1; i >= 0; i--)
{
NodeIndex node = topo_nodes[i];
IExpression factor = factorExprs[node];
ProcessFactor(factor, MessageDirection.Backwards);
}
}
