protected ArrayState AssumeWithArrayRefinement(APC pc, bool positive, BoxedExpression comparison, ArrayState prevState)
{
Contract.Requires(comparison != null);
Contract.Requires(prevState != null);
Contract.Ensures(Contract.Result <ArrayState>() != null);
// Default NonRelational values
var interval = DisInterval.UnknownInterval;
var symbExpression = SymbolicExpressionTracker <BoxedVariable <Variable>, BoxedExpression> .Unknown;
var equalities = SetOfConstraints <BoxedVariable <Variable> > .Unknown;
var disequalities = SetOfConstraints <BoxedVariable <Variable> > .Unknown;
var weakUpperBounds = SetOfConstraints <BoxedVariable <Variable> > .Unknown;
var strictUpperBounds = SetOfConstraints <BoxedVariable <Variable> > .Unknown;
var existential = SetOfConstraints <BoxedVariable <Variable> > .Unknown;
Pair <BoxedVariable <Variable>, BoxedVariable <Variable> > refined;
Variable left, right;
int k;
#region left != right ?
if (positive && comparison.IsCheckExp1NotEqExp2(out left, out right))
{
// refined.One[refined.Two] != right
var b = prevState.CanRefineToArrayLoad(new BoxedVariable <Variable>(left), out refined);
if (!b)
{
// left != refined.One[refined.Two]
b = prevState.CanRefineToArrayLoad(new BoxedVariable <Variable>(right), out refined);
// Swap roles
var tmp = left;
left = right;
right = tmp;
}
if (b)
{
// invariant: "left" is the one to refine.
// TODO: right now we are ignoring the case when both are arrays
interval = prevState.IntervalIfNotNull(left);
var ael = new NonRelationalValueAbstraction <BoxedVariable <Variable>, BoxedExpression>
(interval, symbExpression, equalities,
new SetOfConstraints <BoxedVariable <Variable> >(new BoxedVariable <Variable>(right)),
weakUpperBounds, strictUpperBounds, existential);
var index = ToBoxedExpression(pc, refined.Two).ToNormalizedExpression <Variable>();
return(UpdateArrayAbstractValue(pc, refined.One, index, ael, prevState));
}
}
#endregion
#region left != k ?
BinaryOperator bop;
if (comparison.IsCheckExpOpConst(out bop, out left, out k) &&
prevState.CanRefineToArrayLoad(new BoxedVariable <Variable>(left), out refined))
{
switch (bop)
{
case BinaryOperator.Ceq:
{
interval = positive ? DisInterval.For(k) : DisInterval.NotInThisInterval(DisInterval.For(k));
break;
}
case BinaryOperator.Cne_Un:
{
interval = positive ? DisInterval.NotInThisInterval(DisInterval.For(k)) : DisInterval.For(k);
break;
}
default:
{
return(prevState);
}
}
var ael = new NonRelationalValueAbstraction <BoxedVariable <Variable>, BoxedExpression>
(interval, symbExpression, equalities, disequalities, weakUpperBounds, strictUpperBounds, existential);
var index = ToBoxedExpression(pc, refined.Two).Stripped().ToNormalizedExpression <Variable>();
return(UpdateArrayAbstractValue(pc, refined.One, index, ael, prevState));
}
#endregion
#region left == 0
if (comparison.TryGetFrameworkVariable(out left) &&
prevState.CanRefineToArrayLoad(new BoxedVariable <Variable>(left), out refined))
{
interval = !positive ? DisInterval.Zero : DisInterval.NotZero;
var ael = new NonRelationalValueAbstraction <BoxedVariable <Variable>, BoxedExpression>
(interval, symbExpression, equalities, disequalities, weakUpperBounds, strictUpperBounds, existential);
var index = ToBoxedExpression(pc, refined.Two).Stripped().ToNormalizedExpression <Variable>();
return(UpdateArrayAbstractValue(pc, refined.One, index, ael, prevState));
}
#endregion
return(prevState);
}