public PointsToAnalysisData MergeAnalysisDataForBackEdge(PointsToAnalysisData forwardEdgeAnalysisData, PointsToAnalysisData backEdgeAnalysisData, Func <PointsToAbstractValue, IEnumerable <AnalysisEntity> > getChildAnalysisEntities)
{
Debug.Assert(forwardEdgeAnalysisData != null);
Debug.Assert(backEdgeAnalysisData != null);
// Stop tracking points to values present in both branches if their is an assignment to a may-be null value from the back edge.
// Clone the input forwardEdgeAnalysisData to ensure we don't overwrite the input dictionary.
forwardEdgeAnalysisData = new Dictionary <AnalysisEntity, PointsToAbstractValue>(forwardEdgeAnalysisData);
List <AnalysisEntity> keysInMap1 = forwardEdgeAnalysisData.Keys.ToList();
foreach (var key in keysInMap1)
{
var forwardEdgeValue = forwardEdgeAnalysisData[key];
if (backEdgeAnalysisData.TryGetValue(key, out var backEdgeValue) &&
backEdgeValue != forwardEdgeValue)
{
switch (backEdgeValue.NullState)
{
case NullAbstractValue.MaybeNull:
StopTrackingAnalysisDataForKey();
break;
case NullAbstractValue.NotNull:
if (backEdgeValue.MakeMayBeNull() != forwardEdgeAnalysisData[key])
{
StopTrackingAnalysisDataForKey();
}
break;
}
void StopTrackingAnalysisDataForKey()
{
var childEntities = getChildAnalysisEntities(forwardEdgeValue)
.Union(getChildAnalysisEntities(backEdgeValue));
foreach (var childEntity in childEntities)
{
forwardEdgeAnalysisData[childEntity] = PointsToAbstractValue.Unknown;
}
forwardEdgeAnalysisData[key] = PointsToAbstractValue.Unknown;
}
}
}
var resultMap = Merge(forwardEdgeAnalysisData, backEdgeAnalysisData);
Debug.Assert(Compare(forwardEdgeAnalysisData, resultMap) <= 0);
Debug.Assert(Compare(backEdgeAnalysisData, resultMap) <= 0);
return(resultMap);
}
public PointsToAnalysisData MergeAnalysisDataForBackEdge(PointsToAnalysisData map1, PointsToAnalysisData map2)
{
// Stop tracking points to values present in both branches.
List <AnalysisEntity> keysInMap1 = map1.Keys.ToList();
foreach (var key in keysInMap1)
{
if (map2.TryGetValue(key, out var value2) &&
value2 != map1[key])
{
map1[key] = PointsToAbstractValue.Unknown;
}
}
return(Merge(map1, map2));
}
