public static Dictionary<CFGBlock, List<CFGBlock>> ComputeContainingLoopMap(ICFG cfg)
{
Contract.Requires(cfg != null);
Contract.Ensures(Contract.Result<Dictionary<CFGBlock, List<CFGBlock>>>() != null);
var result = new Dictionary<CFGBlock, List<CFGBlock>>();
var visitedSubroutines = new Set<int>();
var pendingSubroutines = new Stack<Subroutine>();
var pendingAPCs = new Stack<APC>();
var graph = cfg.AsBackwardGraph(includeExceptionEdges:false, skipContracts:true);
foreach (var loophead in cfg.LoopHeads)
{
// push back-edge sources
var loopPC = new APC(loophead, 0, null);
foreach (var pred in cfg.Predecessors(loopPC))
{
if (cfg.IsForwardBackEdge(pred, loopPC))
{
var normalizedPred = new APC(pred.Block, 0, null);
pendingAPCs.Push(normalizedPred);
}
}
var visit = new DepthFirst.Visitor<APC, Unit>(graph,
(APC pc) =>
{
if (pc.SubroutineContext != null)
{
// push continuation PC
pendingAPCs.Push(new APC(pc.SubroutineContext.Head.One, 0, null));
if (visitedSubroutines.AddQ(pc.Block.Subroutine.Id))
{
pendingSubroutines.Push(pc.Block.Subroutine);
}
return false; // stop exploration
}
return !pc.Equals(loopPC);
});
while (pendingAPCs.Count > 0)
{
var root = pendingAPCs.Pop();
visit.VisitSubGraphNonRecursive(root);
while (pendingSubroutines.Count > 0)
{
var sub = pendingSubroutines.Pop();
pendingAPCs.Push(new APC(sub.Exit, 0, null));
}
}
foreach (var visited in visit.Visited)
{
if (visited.SubroutineContext != null) continue; // ignore non-primary pcs
MaterializeContainingLoop(result, visited.Block).AssumeNotNull().Add(loophead);
}
}
return result;
}
protected void PostProcessBlocks()
{
var blockStack = new Stack <CFGBlock> ();
this.successor_edges = new EdgeMap <EdgeTag> (this.successors);
this.edge_info = new DepthFirst.Visitor <CFGBlock, Dummy> (this, null, (block) => blockStack.Push(block), null);
this.edge_info.VisitSubGraphNonRecursive(this.exception_exit);
this.edge_info.VisitSubGraphNonRecursive(this.exit);
this.edge_info.VisitSubGraphNonRecursive(this.entry);
foreach (var successorEdge in this.successor_edges)
{
int idGen = UnusedBlockIndex;
successorEdge.From.Renumber(ref idGen);
}
int idGen1 = 0;
foreach (CFGBlock cfgBlock in blockStack)
{
cfgBlock.Renumber(ref idGen1);
}
SuccessorEdges.Filter((e) => e.From.Index != UnusedBlockIndex);
this.predecessor_edges = this.successor_edges.Reverse();
int finishTime = 0;
var visitor = new DepthFirst.Visitor <CFGBlock, EdgeTag> (this.predecessor_edges, null, block => block.ReversePostOrderIndex = finishTime++, null);
visitor.VisitSubGraphNonRecursive(this.exit);
foreach (CFGBlock node in blockStack)
{
visitor.VisitSubGraphNonRecursive(node);
}
SuccessorEdges.Resort();
this.blocks = blockStack.ToArray();
this.LabelsThatStartBlocks = null;
Builder = null;
}
public static Dictionary <CFGBlock, List <CFGBlock> > ComputeContainingLoopMap(ICFG cfg)
{
Contract.Requires(cfg != null);
Contract.Ensures(Contract.Result <Dictionary <CFGBlock, List <CFGBlock> > >() != null);
var result = new Dictionary <CFGBlock, List <CFGBlock> >();
var visitedSubroutines = new Set <int>();
var pendingSubroutines = new Stack <Subroutine>();
var pendingAPCs = new Stack <APC>();
var graph = cfg.AsBackwardGraph(includeExceptionEdges: false, skipContracts: true);
foreach (var loophead in cfg.LoopHeads)
{
// push back-edge sources
var loopPC = new APC(loophead, 0, null);
foreach (var pred in cfg.Predecessors(loopPC))
{
if (cfg.IsForwardBackEdge(pred, loopPC))
{
var normalizedPred = new APC(pred.Block, 0, null);
pendingAPCs.Push(normalizedPred);
}
}
var visit = new DepthFirst.Visitor <APC, Unit>(graph,
(APC pc) =>
{
if (pc.SubroutineContext != null)
{
// push continuation PC
pendingAPCs.Push(new APC(pc.SubroutineContext.Head.One, 0, null));
if (visitedSubroutines.AddQ(pc.Block.Subroutine.Id))
{
pendingSubroutines.Push(pc.Block.Subroutine);
}
return(false); // stop exploration
}
return(!pc.Equals(loopPC));
});
while (pendingAPCs.Count > 0)
{
var root = pendingAPCs.Pop();
visit.VisitSubGraphNonRecursive(root);
while (pendingSubroutines.Count > 0)
{
var sub = pendingSubroutines.Pop();
pendingAPCs.Push(new APC(sub.Exit, 0, null));
}
}
foreach (var visited in visit.Visited)
{
if (visited.SubroutineContext != null)
{
continue; // ignore non-primary pcs
}
MaterializeContainingLoop(result, visited.Block).AssumeNotNull().Add(loophead);
}
}
return(result);
}