/// <summary>
/// Here we actually add constraints to our state.
/// </summary>
private Domain ConstrainLessThan(Expression var, Expression bound, Domain domain)
{
// First, skip unary coercions on var and bound
SkipConversionDecoder skipper = new SkipConversionDecoder();
var = this.context.Decode <Unit, Expression, SkipConversionDecoder>(var, skipper, Unit.Value);
bound = this.context.Decode <Unit, Expression, SkipConversionDecoder>(bound, skipper, Unit.Value);
Variable left = this.context.Unrefine(var);
Variable right = this.context.Unrefine(bound);
// add the bound to the set of bounds known
SetDomain <Variable> currentBounds =
(domain.Value.Contains(left)) ? domain.Value[left] : SetDomain <Variable> .TopValue;
return(new Domain(domain.Value.Add(left, currentBounds.Add(right))));
}
/// <summary>
/// Here's where the actual work is. We get passed a list of pairs (source,targets) representing
/// the assignments t = source for each t in targets.
///
/// For our domain, we thus add new mappings for all targets by looking up the bounds of the source and map the source bounds to new target bounds.
/// </summary>
public Domain ParallelAssign(Pair <Label, Label> edge, IFunctionalMap <Variable, FList <Variable> > sourceTargetMap, Domain state)
{
EnvironmentDomain <Variable, SetDomain <Variable> > originalState = state.Value;
EnvironmentDomain <Variable, SetDomain <Variable> > newState = originalState;
foreach (Variable source in sourceTargetMap.Keys)
{
FList <Variable> targets = sourceTargetMap[source];
// 1) for each target in this assignment, assign it the same bounds as source.
// 2) since we also have to map the source bounds, we assign it actually the union of all targets of all bounds of the source.
SetDomain <Variable> targetBounds = SetDomain <Variable> .TopValue;
if (originalState.Contains(source))
{
SetDomain <Variable> originalBounds = originalState[source];
foreach (Variable origBound in originalBounds.Elements)
{
FList <Variable> targetBoundNames = sourceTargetMap[origBound];
while (targetBoundNames != null)
{
targetBounds = targetBounds.Add(targetBoundNames.Head);
targetBoundNames = targetBoundNames.Tail;
}
}
}
if (targetBounds.IsTop)
{
// have no bounds, so havoc all targets
while (targets != null)
{
newState = newState.Remove(targets.Head);
targets = targets.Tail;
}
}
else
{
while (targets != null)
{
newState = newState.Add(targets.Head, targetBounds);
targets = targets.Tail;
}
}
}
return(new Domain(newState));
}