public override Answer CheckPredicate(Element /*!*/ e, IExpr /*!*/ pred)
{
//Contract.Requires(pred != null);
//Contract.Requires(e != null);
PolyhedraLatticeElement /*!*/ ple = (PolyhedraLatticeElement)Constrain(e, pred);
Contract.Assert(ple != null);
if (ple.lcs.IsBottom())
{
return(Answer.No);
}
// Note, "pred" may contain expressions that are not understood by the propFactory (in
// particular, this may happen because--currently, and perhaps is a design we'll want
// to change in the future--propFactory deals with BoogiePL expressions whereas "pred"
// may also refer to Equivalences.UninterpFun expressions). Thus, we cannot just
// call propFactory.Not(pred) to get the negation of "pred".
pred = new PolyhedraLatticeNegation(pred);
ple = (PolyhedraLatticeElement)Constrain(e, pred);
if (ple.lcs.IsBottom())
{
return(Answer.Yes);
}
else
{
return(Answer.Maybe);
}
}
public override Element /*!*/ Constrain(Element /*!*/ e, IExpr /*!*/ expr)
{
//Contract.Requires(expr != null);
//Contract.Requires(e != null);
Contract.Ensures(Contract.Result <Element>() != null);
log.DbgMsg(string.Format("Constraining with {0} into {1} ...", expr, this.ToString(e)));
PolyhedraLatticeElement ple = (PolyhedraLatticeElement)e;
if (ple.lcs.IsBottom())
{
return(ple);
}
LinearCondition le = LinearExpressionBuilder.AsCondition(expr);
if (le != null)
{
// update the polyhedron according to the linear expression
Contract.Assume(ple.lcs.Constraints != null);
ArrayList /*LinearConstraint*/ clist = (ArrayList /*!*/ /*LinearConstraint*/)cce.NonNull(ple.lcs.Constraints.Clone());
le.AddToConstraintSystem(clist);
LinearConstraintSystem newLcs = new LinearConstraintSystem(clist);
return(new PolyhedraLatticeElement(newLcs));
}
return(ple);
}
public override bool IsTop(Element /*!*/ element)
{
//Contract.Requires(element != null);
PolyhedraLatticeElement e = (PolyhedraLatticeElement)element;
return(e.lcs.IsTop());
}
public override Answer CheckVariableDisequality(Element /*!*/ e, IVariable /*!*/ var1, IVariable /*!*/ var2)
{
//Contract.Requires(var2 != null);
//Contract.Requires(var1 != null);
//Contract.Requires(e != null);
PolyhedraLatticeElement /*!*/ ple = (PolyhedraLatticeElement)cce.NonNull(e);
Contract.Assume(ple.lcs.Constraints != null);
ArrayList /*LinearConstraint!*//*!*/ clist = (ArrayList /*LinearConstraint!*/)cce.NonNull(ple.lcs.Constraints.Clone());
LinearConstraint /*!*/ lc = new LinearConstraint(LinearConstraint.ConstraintRelation.EQ);
Contract.Assert(lc != null);
lc.SetCoefficient(var1, Rational.ONE);
lc.SetCoefficient(var2, Rational.MINUS_ONE);
clist.Add(lc);
LinearConstraintSystem newLcs = new LinearConstraintSystem(clist);
if (newLcs.IsBottom())
{
return(Answer.Yes);
}
else
{
return(Answer.Maybe);
}
}
public override IExpr /*!*/ ToPredicate(Element /*!*/ element)
{
//Contract.Requires(element != null);
Contract.Ensures(Contract.Result <IExpr>() != null);
PolyhedraLatticeElement e = (PolyhedraLatticeElement)element;
return(e.lcs.ConvertToExpression(factory));
}
/// <summary>
/// Returns true iff a is a subset of this.
/// </summary>
/// <param name="a"></param>
/// <returns></returns>
protected override bool AtMost(Element /*!*/ first, Element /*!*/ second) // this <= that
{
//Contract.Requires(first != null);
//Contract.Requires(second != null);
PolyhedraLatticeElement a = (PolyhedraLatticeElement)first;
PolyhedraLatticeElement b = (PolyhedraLatticeElement)second;
return(b.lcs.IsSubset(a.lcs));
}
public override Lattice.Element /*!*/ NontrivialMeet(Element /*!*/ first, Element /*!*/ second)
{
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result <Lattice.Element>() != null);
PolyhedraLatticeElement aa = (PolyhedraLatticeElement)first;
PolyhedraLatticeElement bb = (PolyhedraLatticeElement)second;
return(new PolyhedraLatticeElement(aa.lcs.Meet(bb.lcs)));
}
public override Element /*!*/ Eliminate(Element /*!*/ e, IVariable /*!*/ variable)
{
//Contract.Requires(variable != null);
//Contract.Requires(e != null);
Contract.Ensures(Contract.Result <Element>() != null);
log.DbgMsg(string.Format("Eliminating {0} ...", variable));
PolyhedraLatticeElement ple = (PolyhedraLatticeElement)e;
if (ple.lcs.IsBottom())
{
return(ple);
}
return(new PolyhedraLatticeElement(ple.lcs.Project(variable)));
}
public override Lattice.Element /*!*/ NontrivialJoin(Element /*!*/ first, Element /*!*/ second)
{
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result <Lattice.Element>() != null);
log.DbgMsg("Joining ...");
log.DbgMsgIndent();
PolyhedraLatticeElement aa = (PolyhedraLatticeElement)first;
PolyhedraLatticeElement bb = (PolyhedraLatticeElement)second;
PolyhedraLatticeElement result = new PolyhedraLatticeElement(aa.lcs.Join(bb.lcs));
log.DbgMsg(string.Format("{0} |_| {1} --> {2}", this.ToString(first), this.ToString(second), this.ToString(result)));
log.DbgMsgUnindent();
return(result);
}
public override Element /*!*/ Rename(Element /*!*/ e, IVariable /*!*/ oldName, IVariable /*!*/ newName)
{
//Contract.Requires(newName != null);
//Contract.Requires(oldName != null);
//Contract.Requires(e != null);
Contract.Ensures(Contract.Result <Element>() != null);
log.DbgMsg(string.Format("Renaming {0} to {1} in {2} ...", oldName, newName, this.ToString(e)));
PolyhedraLatticeElement ple = (PolyhedraLatticeElement)e;
if (ple.lcs.IsBottom())
{
return(ple);
}
return(new PolyhedraLatticeElement(ple.lcs.Rename(oldName, newName)));
}
public override Lattice.Element/*!*/ Widen(Element/*!*/ first, Element/*!*/ second) {
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result<Lattice.Element>() != null);
log.DbgMsg("Widening ...");
log.DbgMsgIndent();
PolyhedraLatticeElement aa = (PolyhedraLatticeElement)first;
PolyhedraLatticeElement bb = (PolyhedraLatticeElement)second;
LinearConstraintSystem lcs = aa.lcs.Widen(bb.lcs);
PolyhedraLatticeElement result = new PolyhedraLatticeElement(lcs);
log.DbgMsg(string.Format("{0} |_| {1} --> {2}", this.ToString(first), this.ToString(second), this.ToString(result)));
log.DbgMsgUnindent();
return result;
}
