private void TransformRegion(IRegion region)
{
List <PredicateCmd> genuineInvariants = new List <PredicateCmd>();
List <PredicateCmd> oldCandidateInvariants = new List <PredicateCmd>();
foreach (var inv in region.RemoveInvariants())
{
string c;
if (Houdini.MatchCandidate(inv.Expr, candidates, out c))
{
Debug.Assert(inv is AssertCmd);
oldCandidateInvariants.Add(inv);
}
else
{
genuineInvariants.Add(inv);
}
}
TransformPow2Candidates(region, oldCandidateInvariants);
TransformImplicationCandidates(region, oldCandidateInvariants);
TransformRemainingCandidates(region, oldCandidateInvariants);
foreach (var p in genuineInvariants)
{
region.AddInvariant(p);
}
}
private void TransformPow2Candidates(IRegion region, List <PredicateCmd> oldCandidateInvariants)
{
IdentifierExpr v = null;
do
{
foreach (var p in oldCandidateInvariants)
{
v = TryGetPow2VariableFromCandidate(p);
if (v != null)
{
break;
}
}
if (v != null)
{
oldCandidateInvariants.RemoveAll(item => TryGetPow2VariableFromCandidate(item)
!= null && TryGetPow2VariableFromCandidate(item).Name.Equals(v.Name));
Function pow2ExistentialFunction = CreateExistentialFunction(
new List <TypedIdent> {
new TypedIdent(Token.NoToken, "x", v.Type)
});
pow2ExistentialFunction.AddAttribute("absdomain", new object[] { "PowDomain" });
existentialFunctions.Add(pow2ExistentialFunction);
region.AddInvariant(new AssertCmd(
Token.NoToken,
new NAryExpr(Token.NoToken, new FunctionCall(pow2ExistentialFunction), new List <Expr> {
v
})));
}
}while (v != null);
}
private void TransformRemainingCandidates(IRegion region, List <PredicateCmd> oldCandidateInvariants)
{
if (oldCandidateInvariants.Count() > 0)
{
List <TypedIdent> args = new List <TypedIdent>();
for (int i = 0; i < oldCandidateInvariants.Count(); i++)
{
args.Add(new TypedIdent(Token.NoToken, "x" + i, Type.Bool));
}
Function existentialFunction = CreateExistentialFunction(args);
existentialFunctions.Add(existentialFunction);
List <Expr> oldCandidateInvariantExprs = new List <Expr>();
foreach (var p in oldCandidateInvariants)
{
string c;
Expr e;
Houdini.GetCandidateWithoutConstant(p.Expr, candidates, out c, out e);
Debug.Assert(e != null);
oldCandidateInvariantExprs.Add(e);
}
region.AddInvariant(new AssertCmd(
Token.NoToken,
new NAryExpr(Token.NoToken, new FunctionCall(existentialFunction), oldCandidateInvariantExprs)));
}
}
private void TransformRemainingCandidates(IRegion region, List <PredicateCmd> oldCandidateInvariants)
{
if (oldCandidateInvariants.Count() > 0)
{
List <Variable> args = new List <Variable>();
for (int i = 0; i < oldCandidateInvariants.Count(); i++)
{
args.Add(new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, "x" + i, Microsoft.Boogie.Type.Bool)));
}
Function existentialFunction = new Function(Token.NoToken, "_existential_func" + counter, args,
new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, "", Microsoft.Boogie.Type.Bool)));
existentialFunctions.Add(existentialFunction);
existentialFunction.AddAttribute("existential", new object[] { Expr.True });
List <Expr> oldCandidateInvariantExprs = new List <Expr>();
foreach (var p in oldCandidateInvariants)
{
string c;
Expr e;
Houdini.GetCandidateWithoutConstant(p.Expr, candidates, out c, out e);
Debug.Assert(e != null);
oldCandidateInvariantExprs.Add(e);
}
region.AddInvariant(new AssertCmd(Token.NoToken, new NAryExpr(Token.NoToken, new FunctionCall(existentialFunction),
oldCandidateInvariantExprs)));
counter++;
}
}
private void TransformImplicationCandidates(IRegion region, List <PredicateCmd> oldCandidateInvariants)
{
IdentifierExpr antecedent = null;
HashSet <IdentifierExpr> visited = new HashSet <IdentifierExpr>();
do
{
PredicateCmd current = null;
foreach (var p in oldCandidateInvariants)
{
antecedent = TryGetNegatedBooleanFromCandidate(p, visited);
if (antecedent != null)
{
visited.Add(antecedent);
current = p;
break;
}
}
if (antecedent != null)
{
Debug.Assert(current != null);
HashSet <PredicateCmd> toRemove = new HashSet <PredicateCmd>();
foreach (var p in oldCandidateInvariants)
{
string c;
Expr e;
Houdini.GetCandidateWithoutConstant(p.Expr, candidates, out c, out e);
Debug.Assert(e != null);
NAryExpr ne = e as NAryExpr;
if (ne != null && ne.Fun is BinaryOperator && ((BinaryOperator)ne.Fun).Op == BinaryOperator.Opcode.Imp &&
ne.Args[0] is IdentifierExpr && ((IdentifierExpr)ne.Args[0]).Name.Equals(antecedent.Name))
{
Expr consequent = ne.Args[1];
toRemove.Add(current);
toRemove.Add(p);
Function implicationExistentialFunction = CreateExistentialFunction(
new List <TypedIdent> {
new TypedIdent(Token.NoToken, "x", Type.Bool), new TypedIdent(Token.NoToken, "y", Type.Bool)
});
implicationExistentialFunction.AddAttribute("absdomain", new object[] { "ImplicationDomain" });
existentialFunctions.Add(implicationExistentialFunction);
region.AddInvariant(new AssertCmd(
Token.NoToken,
new NAryExpr(Token.NoToken, new FunctionCall(implicationExistentialFunction), new List <Expr> {
antecedent, consequent
})));
}
}
oldCandidateInvariants.RemoveAll(item => toRemove.Contains(item));
}
}while (antecedent != null);
}
