public static List <Block /*!*/> /*!*/ UnrollLoops(Block start, int unrollMaxDepth, bool soundLoopUnrolling)
{
Contract.Requires(start != null);
Contract.Requires(0 <= unrollMaxDepth);
Contract.Ensures(cce.NonNullElements(Contract.Result <List <Block> >()));
Dictionary <Block, GraphNode /*!*/> gd = new Dictionary <Block, GraphNode /*!*/>();
HashSet <Block> beingVisited = new HashSet <Block>();
GraphNode gStart = GraphNode.ComputeGraphInfo(null, start, gd, beingVisited);
// Compute SCCs
StronglyConnectedComponents <GraphNode /*!*/> sccs =
new StronglyConnectedComponents <GraphNode /*!*/>(gd.Values, Preds, Succs);
Contract.Assert(sccs != null);
sccs.Compute();
Dictionary <GraphNode /*!*/, SCC <GraphNode /*!*/> > containingSCC =
new Dictionary <GraphNode /*!*/, SCC <GraphNode /*!*/> >();
foreach (SCC <GraphNode /*!*/> scc in sccs)
{
foreach (GraphNode /*!*/ n in scc)
{
Contract.Assert(n != null);
containingSCC[n] = scc;
}
}
LoopUnroll lu = new LoopUnroll(unrollMaxDepth, soundLoopUnrolling, containingSCC, new List <Block /*!*/>());
lu.Visit(gStart);
lu.newBlockSeqGlobal.Reverse();
return(lu.newBlockSeqGlobal);
}
public static List<Block/*!*/>/*!*/ UnrollLoops(Block start, int unrollMaxDepth, bool soundLoopUnrolling) {
Contract.Requires(start != null);
Contract.Requires(0 <= unrollMaxDepth);
Contract.Ensures(cce.NonNullElements(Contract.Result<List<Block>>()));
Dictionary<Block, GraphNode/*!*/> gd = new Dictionary<Block, GraphNode/*!*/>();
HashSet<Block> beingVisited = new HashSet<Block>();
GraphNode gStart = GraphNode.ComputeGraphInfo(null, start, gd, beingVisited);
// Compute SCCs
StronglyConnectedComponents<GraphNode/*!*/> sccs =
new StronglyConnectedComponents<GraphNode/*!*/>(gd.Values, Preds, Succs);
Contract.Assert(sccs != null);
sccs.Compute();
Dictionary<GraphNode/*!*/, SCC<GraphNode/*!*/>> containingSCC = new Dictionary<GraphNode/*!*/, SCC<GraphNode/*!*/>>();
foreach (SCC<GraphNode/*!*/> scc in sccs) {
foreach (GraphNode/*!*/ n in scc) {
Contract.Assert(n != null);
containingSCC[n] = scc;
}
}
LoopUnroll lu = new LoopUnroll(unrollMaxDepth, soundLoopUnrolling, containingSCC, new List<Block/*!*/>());
lu.Visit(gStart);
lu.newBlockSeqGlobal.Reverse();
return lu.newBlockSeqGlobal;
}
Block Visit(GraphNode node)
{
Contract.Requires(node != null);
Contract.Ensures(Contract.Result <Block>() != null);
Block orig = node.Block;
if (newBlocks.TryGetValue(orig, out var nw))
{
Contract.Assert(nw != null);
}
else
{
List <Cmd> body;
TransferCmd tcmd;
Contract.Assert(orig.TransferCmd != null);
if (next == null && node.IsCutPoint)
{
// as the body, use the assert/assume commands that make up the loop invariant
body = new List <Cmd>();
foreach (Cmd /*!*/ c in node.Body)
{
Contract.Assert(c != null);
if (c is PredicateCmd || c is CommentCmd)
{
body.Add(c);
}
else
{
break;
}
}
if (soundLoopUnrolling)
{
body.Add(new AssertCmd(orig.tok, Bpl.Expr.False));
}
else
{
body.Add(new AssumeCmd(orig.tok, Bpl.Expr.False));
}
tcmd = new ReturnCmd(orig.TransferCmd.tok);
}
else
{
body = node.Body;
List <Block> newSuccs = new List <Block>();
foreach (GraphNode succ in node.ForwardEdges)
{
Block s;
if (containingSCC[node] == containingSCC[succ])
{
s = Visit(succ);
}
else
{
Contract.Assert(head != null); // follows from object invariant
s = head.Visit(succ);
}
newSuccs.Add(s);
}
Contract.Assert(next != null ||
node.BackEdges.Count == 0); // follows from if-else test above and the GraphNode invariant
foreach (GraphNode succ in node.BackEdges)
{
Contract.Assert(next != null); // since if we get here, node.BackEdges.Count != 0
Block s = next.Visit(succ);
newSuccs.Add(s);
}
if (newSuccs.Count == 0)
{
tcmd = new ReturnCmd(orig.TransferCmd.tok);
}
else
{
tcmd = new GotoCmd(orig.TransferCmd.tok, newSuccs);
}
}
nw = new Block(orig.tok, orig.Label + "#" + this.c, body, tcmd);
newBlocks.Add(orig, nw);
newBlockSeqGlobal.Add(nw);
}
return(nw);
}
