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-rw-r--r--Source/VCGeneration/SmartBlockPredicator.cs528
1 files changed, 0 insertions, 528 deletions
diff --git a/Source/VCGeneration/SmartBlockPredicator.cs b/Source/VCGeneration/SmartBlockPredicator.cs
deleted file mode 100644
index b4f5a3df..00000000
--- a/Source/VCGeneration/SmartBlockPredicator.cs
+++ /dev/null
@@ -1,528 +0,0 @@
-using Graphing;
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Diagnostics.Contracts;
-using System.Linq;
-
-namespace Microsoft.Boogie {
-
-public class SmartBlockPredicator {
-
- Program prog;
- Implementation impl;
- Graph<Block> blockGraph;
- List<Tuple<Block, bool>> sortedBlocks;
-
- Func<Procedure, bool> useProcedurePredicates;
-
- Dictionary<Block, Variable> predMap, defMap;
- Dictionary<Block, HashSet<Variable>> ownedMap;
- Dictionary<Block, Block> parentMap;
- Dictionary<Block, PartInfo> partInfo;
-
- IdentifierExpr fp;
- Dictionary<Microsoft.Boogie.Type, IdentifierExpr> havocVars =
- new Dictionary<Microsoft.Boogie.Type, IdentifierExpr>();
- Dictionary<Block, Expr> blockIds = new Dictionary<Block, Expr>();
- HashSet<Block> doneBlocks = new HashSet<Block>();
- bool myUseProcedurePredicates;
- UniformityAnalyser uni;
-
- SmartBlockPredicator(Program p, Implementation i, Func<Procedure, bool> upp, UniformityAnalyser u) {
- prog = p;
- impl = i;
- useProcedurePredicates = upp;
- myUseProcedurePredicates = useProcedurePredicates(i.Proc);
- uni = u;
- }
-
- void PredicateCmd(Expr p, List<Block> blocks, Block block, Cmd cmd, out Block nextBlock) {
- var cCmd = cmd as CallCmd;
- if (cCmd != null && !useProcedurePredicates(cCmd.Proc)) {
- if (p == null) {
- block.Cmds.Add(cmd);
- nextBlock = block;
- return;
- }
-
- var trueBlock = new Block();
- blocks.Add(trueBlock);
- trueBlock.Label = block.Label + ".call.true";
- trueBlock.Cmds.Add(new AssumeCmd(Token.NoToken, p));
- trueBlock.Cmds.Add(cmd);
-
- var falseBlock = new Block();
- blocks.Add(falseBlock);
- falseBlock.Label = block.Label + ".call.false";
- falseBlock.Cmds.Add(new AssumeCmd(Token.NoToken, Expr.Not(p)));
-
- var contBlock = new Block();
- blocks.Add(contBlock);
- contBlock.Label = block.Label + ".call.cont";
-
- block.TransferCmd =
- new GotoCmd(Token.NoToken, new BlockSeq(trueBlock, falseBlock));
- trueBlock.TransferCmd = falseBlock.TransferCmd =
- new GotoCmd(Token.NoToken, new BlockSeq(contBlock));
- nextBlock = contBlock;
- } else {
- PredicateCmd(p, block.Cmds, cmd);
- nextBlock = block;
- }
- }
-
- void PredicateCmd(Expr p, CmdSeq cmdSeq, Cmd cmd) {
- if (cmd is CallCmd) {
- var cCmd = (CallCmd)cmd;
- Debug.Assert(useProcedurePredicates(cCmd.Proc));
- cCmd.Ins.Insert(0, p != null ? p : Expr.True);
- cmdSeq.Add(cCmd);
- } else if (p == null) {
- cmdSeq.Add(cmd);
- } else if (cmd is AssignCmd) {
- var aCmd = (AssignCmd)cmd;
- cmdSeq.Add(new AssignCmd(Token.NoToken, aCmd.Lhss,
- new List<Expr>(aCmd.Lhss.Zip(aCmd.Rhss, (lhs, rhs) =>
- new NAryExpr(Token.NoToken,
- new IfThenElse(Token.NoToken),
- new ExprSeq(p, rhs, lhs.AsExpr))))));
- } else if (cmd is AssertCmd) {
- var aCmd = (AssertCmd)cmd;
- Expr newExpr = new EnabledReplacementVisitor(p).VisitExpr(aCmd.Expr);
- aCmd.Expr = QKeyValue.FindBoolAttribute(aCmd.Attributes, "do_not_predicate") ? newExpr : Expr.Imp(p, newExpr);
- cmdSeq.Add(aCmd);
- } else if (cmd is AssumeCmd) {
- var aCmd = (AssumeCmd)cmd;
- cmdSeq.Add(new AssumeCmd(Token.NoToken, Expr.Imp(p, aCmd.Expr)));
- } else if (cmd is HavocCmd) {
- var hCmd = (HavocCmd)cmd;
- foreach (IdentifierExpr v in hCmd.Vars) {
- Microsoft.Boogie.Type type = v.Decl.TypedIdent.Type;
- Contract.Assert(type != null);
-
- IdentifierExpr havocTempExpr;
- if (havocVars.ContainsKey(type)) {
- havocTempExpr = havocVars[type];
- } else {
- var havocVar = new LocalVariable(Token.NoToken,
- new TypedIdent(Token.NoToken,
- "_HAVOC_" + type.ToString(), type));
- impl.LocVars.Add(havocVar);
- havocVars[type] = havocTempExpr =
- new IdentifierExpr(Token.NoToken, havocVar);
- }
- cmdSeq.Add(new HavocCmd(Token.NoToken,
- new IdentifierExprSeq(havocTempExpr)));
- cmdSeq.Add(Cmd.SimpleAssign(Token.NoToken, v,
- new NAryExpr(Token.NoToken,
- new IfThenElse(Token.NoToken),
- new ExprSeq(p, havocTempExpr, v))));
- }
- } else if (cmd is CommentCmd) {
- // skip
- } else if (cmd is StateCmd) {
- var sCmd = (StateCmd)cmd;
- var newCmdSeq = new CmdSeq();
- foreach (Cmd c in sCmd.Cmds)
- PredicateCmd(p, newCmdSeq, c);
- sCmd.Cmds = newCmdSeq;
- cmdSeq.Add(sCmd);
- } else {
- Console.WriteLine("Unsupported cmd: " + cmd.GetType().ToString());
- }
- }
-
- // hasPredicatedRegion is true iff the block or its targets are predicated
- // (i.e. we enter, stay within or exit a predicated region).
- void PredicateTransferCmd(Expr p, Block src, CmdSeq cmdSeq, TransferCmd cmd, out bool hasPredicatedRegion) {
- hasPredicatedRegion = predMap.ContainsKey(src);
-
- if (cmd is GotoCmd) {
- var gCmd = (GotoCmd)cmd;
-
- hasPredicatedRegion = hasPredicatedRegion ||
- gCmd.labelTargets.Cast<Block>().Any(b => predMap.ContainsKey(b));
-
- if (gCmd.labelTargets.Length == 1) {
- if (defMap.ContainsKey(gCmd.labelTargets[0]))
- PredicateCmd(p, cmdSeq,
- Cmd.SimpleAssign(Token.NoToken,
- Expr.Ident(predMap[gCmd.labelTargets[0]]), Expr.True));
- } else {
- Debug.Assert(gCmd.labelTargets.Length > 1);
- Debug.Assert(gCmd.labelTargets.Cast<Block>().All(t => uni.IsUniform(impl.Name, t) ||
- partInfo.ContainsKey(t)));
- foreach (Block target in gCmd.labelTargets) {
- if (!partInfo.ContainsKey(target))
- continue;
-
- var part = partInfo[target];
- if (defMap.ContainsKey(part.realDest))
- PredicateCmd(p, cmdSeq,
- Cmd.SimpleAssign(Token.NoToken,
- Expr.Ident(predMap[part.realDest]), part.pred));
- var predsExitingLoop = new Dictionary<Block, List<Expr>>();
- foreach (Block exit in LoopsExited(src, target)) {
- List<Expr> predList;
- if (!predsExitingLoop.ContainsKey(exit))
- predList = predsExitingLoop[exit] = new List<Expr>();
- else
- predList = predsExitingLoop[exit];
- predList.Add(part.pred);
- }
- foreach (var pred in predsExitingLoop) {
- PredicateCmd(p, cmdSeq,
- Cmd.SimpleAssign(Token.NoToken,
- Expr.Ident(predMap[pred.Key]),
- Expr.Not(pred.Value.Aggregate(Expr.Or))));
- }
- }
- }
- } else if (cmd is ReturnCmd) {
- // Blocks which end in a return will never share a predicate with a block
- // which appears after it. Furthermore, such a block cannot be part of a
- // loop. So it is safe to do nothing here.
- } else {
- Console.WriteLine("Unsupported cmd: " + cmd.GetType().ToString());
- }
- }
-
- Variable FreshPredicate(ref int predCount) {
- var pVar = new LocalVariable(Token.NoToken,
- new TypedIdent(Token.NoToken,
- "p" + predCount++,
- Microsoft.Boogie.Type.Bool));
- impl.LocVars.Add(pVar);
- return pVar;
- }
-
- void AssignPredicates(Graph<Block> blockGraph,
- DomRelation<Block> dom,
- DomRelation<Block> pdom,
- IEnumerator<Tuple<Block, bool>> i,
- Variable headPredicate,
- ref int predCount) {
- var header = i.Current.Item1;
- var regionPreds = new List<Tuple<Block, Variable>>();
- var ownedPreds = new HashSet<Variable>();
- ownedMap[header] = ownedPreds;
-
- if (headPredicate != null) {
- predMap[header] = headPredicate;
- defMap[header] = headPredicate;
- regionPreds.Add(new Tuple<Block, Variable>(header, headPredicate));
- }
-
- while (i.MoveNext()) {
- var block = i.Current;
- if (uni != null && uni.IsUniform(impl.Name, block.Item1))
- continue;
- if (block.Item2) {
- if (block.Item1 == header)
- return;
- } else {
- if (blockGraph.Headers.Contains(block.Item1)) {
- parentMap[block.Item1] = header;
- var loopPred = FreshPredicate(ref predCount);
- ownedPreds.Add(loopPred);
- AssignPredicates(blockGraph, dom, pdom, i, loopPred, ref predCount);
- } else {
- bool foundExisting = false;
- foreach (var regionPred in regionPreds) {
- if (dom.DominatedBy(block.Item1, regionPred.Item1) &&
- pdom.DominatedBy(regionPred.Item1, block.Item1)) {
- predMap[block.Item1] = regionPred.Item2;
- foundExisting = true;
- break;
- }
- }
- if (!foundExisting) {
- var condPred = FreshPredicate(ref predCount);
- predMap[block.Item1] = condPred;
- defMap[block.Item1] = condPred;
- ownedPreds.Add(condPred);
- regionPreds.Add(new Tuple<Block, Variable>(block.Item1, condPred));
- }
- }
- }
- }
- }
-
- void AssignPredicates() {
- DomRelation<Block> dom = blockGraph.DominatorMap;
-
- Graph<Block> dualGraph = blockGraph.Dual(new Block());
- DomRelation<Block> pdom = dualGraph.DominatorMap;
-
- var iter = sortedBlocks.GetEnumerator();
- if (!iter.MoveNext()) {
- predMap = defMap = null;
- ownedMap = null;
- return;
- }
-
- int predCount = 0;
- predMap = new Dictionary<Block, Variable>();
- defMap = new Dictionary<Block, Variable>();
- ownedMap = new Dictionary<Block, HashSet<Variable>>();
- parentMap = new Dictionary<Block, Block>();
- AssignPredicates(blockGraph, dom, pdom, iter,
- myUseProcedurePredicates ? impl.InParams[0] : null,
- ref predCount);
- }
-
- IEnumerable<Block> LoopsExited(Block src, Block dest) {
- var i = sortedBlocks.GetEnumerator();
- while (i.MoveNext()) {
- var b = i.Current;
- if (b.Item1 == src) {
- return LoopsExitedForwardEdge(dest, i);
- } else if (b.Item1 == dest) {
- return LoopsExitedBackEdge(src, i);
- }
- }
- Debug.Assert(false);
- return null;
- }
-
- private IEnumerable<Block> LoopsExitedBackEdge(Block src, IEnumerator<Tuple<Block, bool>> i) {
- var headsSeen = new HashSet<Block>();
- while (i.MoveNext()) {
- var b = i.Current;
- if (!b.Item2 && blockGraph.Headers.Contains(b.Item1))
- headsSeen.Add(b.Item1);
- else if (b.Item2)
- headsSeen.Remove(b.Item1);
- if (b.Item1 == src)
- return headsSeen;
- }
- Debug.Assert(false);
- return null;
- }
-
- private IEnumerable<Block> LoopsExitedForwardEdge(Block dest, IEnumerator<Tuple<Block, bool>> i) {
- var headsSeen = new HashSet<Block>();
- while (i.MoveNext()) {
- var b = i.Current;
- if (b.Item1 == dest)
- yield break;
- else if (!b.Item2 && blockGraph.Headers.Contains(b.Item1))
- headsSeen.Add(b.Item1);
- else if (b.Item2 && !headsSeen.Contains(b.Item1))
- yield return b.Item1;
- }
- Debug.Assert(false);
- }
-
- class PartInfo {
- public PartInfo(Expr p, Block r) { pred = p; realDest = r; }
- public Expr pred;
- public Block realDest;
- }
-
- Dictionary<Block, PartInfo> BuildPartitionInfo() {
- var partInfo = new Dictionary<Block, PartInfo>();
- foreach (var block in blockGraph.Nodes) {
- if (uni.IsUniform(impl.Name, block))
- continue;
-
- var parts = block.Cmds.Cast<Cmd>().TakeWhile(
- c => c is AssumeCmd &&
- QKeyValue.FindBoolAttribute(((AssumeCmd)c).Attributes, "partition"));
-
- Expr pred = null;
- if (parts.Count() > 0) {
- pred = parts.Select(a => ((AssumeCmd)a).Expr).Aggregate(Expr.And);
- block.Cmds =
- new CmdSeq(block.Cmds.Cast<Cmd>().Skip(parts.Count()).ToArray());
- } else {
- continue;
- }
-
- Block realDest = block;
- if (block.Cmds.Length == 0) {
- var gc = block.TransferCmd as GotoCmd;
- if (gc != null && gc.labelTargets.Length == 1)
- realDest = gc.labelTargets[0];
- }
- partInfo[block] = new PartInfo(pred, realDest);
- }
-
- return partInfo;
- }
-
- void PredicateImplementation() {
- blockGraph = prog.ProcessLoops(impl);
- sortedBlocks = blockGraph.LoopyTopSort();
-
- AssignPredicates();
- partInfo = BuildPartitionInfo();
-
- if (myUseProcedurePredicates)
- fp = Expr.Ident(impl.InParams[0]);
-
- var newBlocks = new List<Block>();
- Block prevBlock = null;
- foreach (var n in sortedBlocks) {
- if (predMap.ContainsKey(n.Item1)) {
- var p = predMap[n.Item1];
- var pExpr = Expr.Ident(p);
-
- if (n.Item2) {
- var backedgeBlock = new Block();
- newBlocks.Add(backedgeBlock);
-
- backedgeBlock.Label = n.Item1.Label + ".backedge";
- backedgeBlock.Cmds = new CmdSeq(new AssumeCmd(Token.NoToken, pExpr,
- new QKeyValue(Token.NoToken, "backedge", new List<object>(), null)));
- backedgeBlock.TransferCmd = new GotoCmd(Token.NoToken,
- new BlockSeq(n.Item1));
-
- var tailBlock = new Block();
- newBlocks.Add(tailBlock);
-
- tailBlock.Label = n.Item1.Label + ".tail";
- tailBlock.Cmds = new CmdSeq(new AssumeCmd(Token.NoToken,
- Expr.Not(pExpr)));
-
- if (uni != null && !uni.IsUniform(impl.Name, n.Item1)) {
- uni.AddNonUniform(impl.Name, backedgeBlock);
- uni.AddNonUniform(impl.Name, tailBlock);
- }
-
- if (prevBlock != null)
- prevBlock.TransferCmd = new GotoCmd(Token.NoToken,
- new BlockSeq(backedgeBlock, tailBlock));
- prevBlock = tailBlock;
- } else {
- PredicateBlock(pExpr, n.Item1, newBlocks, ref prevBlock);
- }
- } else {
- if (!n.Item2) {
- PredicateBlock(null, n.Item1, newBlocks, ref prevBlock);
- }
- }
- }
-
- if (prevBlock != null)
- prevBlock.TransferCmd = new ReturnCmd(Token.NoToken);
-
- impl.Blocks = newBlocks;
- }
-
- private void PredicateBlock(Expr pExpr, Block block, List<Block> newBlocks, ref Block prevBlock) {
- var firstBlock = block;
-
- var oldCmdSeq = block.Cmds;
- block.Cmds = new CmdSeq();
- newBlocks.Add(block);
- if (prevBlock != null) {
- prevBlock.TransferCmd = new GotoCmd(Token.NoToken, new BlockSeq(block));
- }
-
- if (parentMap.ContainsKey(block)) {
- var parent = parentMap[block];
- if (predMap.ContainsKey(parent)) {
- var parentPred = predMap[parent];
- if (parentPred != null) {
- block.Cmds.Add(new AssertCmd(Token.NoToken,
- pExpr != null ? (Expr)Expr.Imp(pExpr, Expr.Ident(parentPred))
- : Expr.Ident(parentPred)));
- }
- }
- }
-
- var transferCmd = block.TransferCmd;
- foreach (Cmd cmd in oldCmdSeq)
- PredicateCmd(pExpr, newBlocks, block, cmd, out block);
-
- if (ownedMap.ContainsKey(firstBlock)) {
- var owned = ownedMap[firstBlock];
- foreach (var v in owned)
- block.Cmds.Add(Cmd.SimpleAssign(Token.NoToken, Expr.Ident(v), Expr.False));
- }
-
- bool hasPredicatedRegion;
- PredicateTransferCmd(pExpr, block, block.Cmds, transferCmd, out hasPredicatedRegion);
-
- if (hasPredicatedRegion)
- prevBlock = block;
- else
- prevBlock = null;
-
- doneBlocks.Add(block);
- }
-
- private Expr CreateIfFPThenElse(Expr then, Expr eElse) {
- if (myUseProcedurePredicates) {
- return new NAryExpr(Token.NoToken,
- new IfThenElse(Token.NoToken),
- new ExprSeq(fp, then, eElse));
- } else {
- return then;
- }
- }
-
- public static void Predicate(Program p,
- Func<Procedure, bool> useProcedurePredicates = null,
- UniformityAnalyser uni = null) {
- useProcedurePredicates = useProcedurePredicates ?? (proc => false);
- if (uni != null) {
- var oldUPP = useProcedurePredicates;
- useProcedurePredicates = proc => oldUPP(proc) && !uni.IsUniform(proc.Name);
- }
-
- foreach (var decl in p.TopLevelDeclarations.ToList()) {
- if (decl is Procedure || decl is Implementation) {
- var proc = decl as Procedure;
- Implementation impl = null;
- if (proc == null) {
- impl = (Implementation)decl;
- proc = impl.Proc;
- }
-
- bool upp = useProcedurePredicates(proc);
- if (upp) {
- var dwf = (DeclWithFormals)decl;
- var fpVar = new Formal(Token.NoToken,
- new TypedIdent(Token.NoToken, "_P",
- Microsoft.Boogie.Type.Bool),
- /*incoming=*/true);
- dwf.InParams = new VariableSeq(
- (new Variable[] {fpVar}.Concat(dwf.InParams.Cast<Variable>()))
- .ToArray());
-
- if (impl == null) {
- var newRequires = new RequiresSeq();
- foreach (Requires r in proc.Requires) {
- newRequires.Add(new Requires(r.Free,
- new EnabledReplacementVisitor(new IdentifierExpr(Token.NoToken, fpVar)).VisitExpr(r.Condition)));
- }
- var newEnsures = new EnsuresSeq();
- foreach (Ensures e in proc.Ensures) {
- newEnsures.Add(new Ensures(e.Free,
- new EnabledReplacementVisitor(new IdentifierExpr(Token.NoToken, fpVar)).VisitExpr(e.Condition)));
- }
- }
- }
-
- if (impl != null) {
- try {
- new SmartBlockPredicator(p, impl, useProcedurePredicates, uni).PredicateImplementation();
- } catch (Program.IrreducibleLoopException) { }
- }
- }
- }
- }
-
- public static void Predicate(Program p, Implementation impl) {
- try {
- new SmartBlockPredicator(p, impl, proc => false, null).PredicateImplementation();
- }
- catch (Program.IrreducibleLoopException) { }
- }
-
-}
-
-}
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