private static GlobalFlowStateDictionaryAnalysisValue CreateAnalysisValue(
IDeferredTypeEntity entity,
IOperation parameterOrLocalReferenceOperation,
GlobalFlowStateDictionaryAnalysisValue defaultValue,
EnumerationCount enumerationCount)
{
var operationsSetBuilder = PooledHashSet <IOperation> .GetInstance();
operationsSetBuilder.Add(parameterOrLocalReferenceOperation);
var newInvocationSet = new TrackingEnumerationSet(
operationsSetBuilder.ToImmutableAndFree(),
enumerationCount);
var trackedEntitiesBuilder = PooledDictionary <IDeferredTypeEntity, TrackingEnumerationSet> .GetInstance();
trackedEntitiesBuilder.Add(entity, newInvocationSet);
var analysisValue = new GlobalFlowStateDictionaryAnalysisValue(
trackedEntitiesBuilder.ToImmutableDictionaryAndFree(),
GlobalFlowStateDictionaryAnalysisValueKind.Known);
return(defaultValue.Kind == GlobalFlowStateDictionaryAnalysisValueKind.Known
? GlobalFlowStateDictionaryAnalysisValue.Merge(analysisValue, defaultValue, false)
: analysisValue);
}
private void UpdateGlobalValue(GlobalFlowStateDictionaryAnalysisValue value)
{
if (value.Kind == GlobalFlowStateDictionaryAnalysisValueKind.Known)
{
var newState = GlobalFlowStateDictionaryAnalysisValue.Merge(GlobalState, value, false);
SetAbstractValue(GlobalEntity, newState);
}
}
private GlobalFlowStateDictionaryAnalysisValue CreateAndUpdateAnalysisValue(
IOperation parameterOrLocalOperation,
IDeferredTypeEntity entity,
GlobalFlowStateDictionaryAnalysisValue defaultValue,
EnumerationCount enumerationCount)
{
var analysisValueForNewEntity = CreateAnalysisValue(entity, parameterOrLocalOperation, defaultValue, enumerationCount);
UpdateGlobalValue(analysisValueForNewEntity);
return(analysisValueForNewEntity);
}
private GlobalFlowStateDictionaryAnalysisValue VisitLocalOrParameter(ITypeSymbol?typeSymbol, IOperation parameterOrLocalReferenceOperation, GlobalFlowStateDictionaryAnalysisValue defaultValue)
{
RoslynDebug.Assert(parameterOrLocalReferenceOperation is IParameterReferenceOperation or ILocalReferenceOperation);
if (!IsDeferredType(typeSymbol, _wellKnownSymbolsInfo.AdditionalDeferredTypes))
{
return(defaultValue);
}
var enumerationCount = GetEnumerationCount(parameterOrLocalReferenceOperation, _wellKnownSymbolsInfo);
if (enumerationCount is EnumerationCount.Zero or EnumerationCount.None)
{
return(defaultValue);
}
if (DataFlowAnalysisContext.PointsToAnalysisResult == null)
{
return(defaultValue);
}
var pointToResult = DataFlowAnalysisContext.PointsToAnalysisResult[parameterOrLocalReferenceOperation.Kind, parameterOrLocalReferenceOperation.Syntax];
if (pointToResult.Kind != PointsToAbstractValueKind.KnownLocations)
{
return(defaultValue);
}
if (pointToResult.Locations.Any(
l => !IsDeferredType(l.LocationType?.OriginalDefinition, _wellKnownSymbolsInfo.AdditionalDeferredTypes)))
{
return(defaultValue);
}
return(VisitDeferTypeEntities(
DataFlowAnalysisContext.PointsToAnalysisResult,
parameterOrLocalReferenceOperation,
defaultValue,
enumerationCount));
}
/// <summary>
/// Visit all the possible deferred type entities referenced by <param name="parameterOrLocalOperation"/>.
/// </summary>
private GlobalFlowStateDictionaryAnalysisValue VisitDeferTypeEntities(
PointsToAnalysisResult pointsToAnalysisResult,
IOperation parameterOrLocalOperation,
GlobalFlowStateDictionaryAnalysisValue defaultValue,
EnumerationCount enumerationCount)
{
RoslynDebug.Assert(parameterOrLocalOperation is IParameterReferenceOperation or ILocalReferenceOperation);
// With the initial operation as the root, expand it if
// the operation is parameter or local reference. It has only one pointToAnalysisResult, and it is a deferred execution invocation.
// Visit its argument.
// e.g.
// var a = b.Concat(c);
// a.ElementAt(10);
// When we visit 'a.Element(10)' and look back to 'b.Concat(c)', also try to visit 'b' and 'c'.
//
// Update the analysis value when reach one of the following nodes.
// 1. A parameter or local that has symbol, but no creationOperation.
// e.g.
// void Bar(IEnumerable<int> b, IEnumerable<int> c)
// {
// var a = b.Concat(c);
// a.ElementAt(10);
// }
// When 'a.ElementAt(10)' is called, 'b' and 'c' are enumerated once.
//
// 2. Invocation operation that returns a deferred type.
// e.g.
// void Bar()
// {
// var a = Enumerable.Range(1, 1);
// var b = Enumerable.Range(2, 2);
// var c = a.Concat(b);
// c.ElementAt(10);
// }
// When 'c.ElementAt(10)' is called, then 'Enumerable.Range(1, 1)', 'Enumerable.Range(2, 2)' and 'a.Concat(b)' are enumerated.
// 3. A parameter or local reference operation with multiple AbstractLocations. Stop expanding the tree at this node
// because we don't know how to proceed.
// e.g.
// void Bar(bool flag)
// {
// var a = flag ? Enumerable.Range(1, 1) : Enumerable.Range(2, 2);
// a.ElementAt(10);
// }
var queue = new Queue <IOperation>();
queue.Enqueue(parameterOrLocalOperation);
var resultAnalysisValue = defaultValue;
while (queue.Count > 0)
{
var currentOperation = queue.Dequeue();
if (currentOperation is IParameterReferenceOperation or ILocalReferenceOperation)
{
var result = pointsToAnalysisResult[currentOperation];
if (result.Kind != PointsToAbstractValueKind.KnownLocations || result.Locations.IsEmpty)
{
continue;
}
// Expand if there is only one AbstractLocation for this operation.
if (result.Locations.Count == 1)
{
var location = result.Locations.Single();
var creationOperation = location.Creation;
// Node 1: A parameter or local that has symbol, but no creation operation.
if (creationOperation == null &&
location.Symbol != null &&
IsDeferredType(location.LocationType?.OriginalDefinition, _wellKnownSymbolsInfo.AdditionalDeferredTypes))
{
var analysisValue = CreateAndUpdateAnalysisValue(currentOperation, new DeferredTypeSymbolEntity(location.Symbol), defaultValue, enumerationCount);
resultAnalysisValue = GlobalFlowStateDictionaryAnalysisValue.Merge(resultAnalysisValue, analysisValue, false);
continue;
}
if (creationOperation is IInvocationOperation invocationCreationOperation)
{
// Try to expand the argument of this invocation operation.
ExpandInvocationOperation(invocationCreationOperation, _wellKnownSymbolsInfo, queue);
var creationMethod = invocationCreationOperation.TargetMethod.ReducedFrom ?? invocationCreationOperation.TargetMethod;
// Make sure this creation operation is not 'AsEnumerable', which only do a cast, and do not create new IEnumerable type.
if (!_wellKnownSymbolsInfo.NoEffectLinqChainMethods.Contains(creationMethod.OriginalDefinition) &&
IsDeferredType(invocationCreationOperation.Type?.OriginalDefinition, _wellKnownSymbolsInfo.AdditionalDeferredTypes))
{
// Node 2: Invocation operation that returns a deferred type.
var analysisValue =
CreateAndUpdateAnalysisValue(currentOperation, new DeferredTypeCreationEntity(invocationCreationOperation), defaultValue, enumerationCount);
resultAnalysisValue = GlobalFlowStateDictionaryAnalysisValue.Merge(resultAnalysisValue, analysisValue, false);
}
continue;
}
}
else
{
// Make sure all the locations are pointing to a deferred type.
if (result.Locations.Any(
l => !IsDeferredType(l.LocationType?.OriginalDefinition, _wellKnownSymbolsInfo.AdditionalDeferredTypes)))
{
continue;
}
// Node 3: A parameter or local reference operation with multiple AbstractLocations.
var analysisValue = CreateAndUpdateAnalysisValue(
currentOperation,
new DeferredTypeEntitySet(result.Locations),
defaultValue,
enumerationCount);
resultAnalysisValue = GlobalFlowStateDictionaryAnalysisValue.Merge(resultAnalysisValue, analysisValue, false);
}
}
// Make sure we iterate into the nested operations.
// e.g.
// var a = b.Concat(c).Concat(d.Concat(e));
// Make sure 'd.Concat(e)' is expanded so that 'd' and 'e' could be found.
if (currentOperation is IInvocationOperation invocationOperation)
{
ExpandInvocationOperation(invocationOperation, _wellKnownSymbolsInfo, queue);
}
// Expand the implicit conversion operation if it is converting a deferred type to another deferred type.
// This might happen in such case:
// var c = a.OrderBy(i => i).Concat(b)
// The tree would be:
// a.OrderBy(i => i).Concat(b) (root)
// / \
// ArgumentOperation ArgumentOperation
// / \
// Conversion *(expand this node) b
// /
// a.OrderBy(i => i)
// /
// ArgumentOperation
// /
// a
if (currentOperation is IConversionOperation conversionOperation)
{
ExpandConversionOperation(conversionOperation, _wellKnownSymbolsInfo, queue);
}
}
return(resultAnalysisValue);
}
protected override void SetAbstractValueForAssignment(
AnalysisEntity targetAnalysisEntity, IOperation?assignedValueOperation, GlobalFlowStateDictionaryAnalysisValue assignedValue)
{
if (assignedValueOperation is null || !IsDeferredType(assignedValueOperation.Type?.OriginalDefinition, _wellKnownSymbolsInfo.AdditionalDeferredTypes))
{
return;
}
var deferredTypeCreationEntity = new DeferredTypeCreationEntity(assignedValueOperation);
if (GlobalState.TrackedEntities.ContainsKey(deferredTypeCreationEntity))
{
// An operation create an 'IEnumerable' entity is visited again in an AssignmentOperation, this could happens in cases like
// foreach (var x in collection)
// {
// var a = CreateIEnumerable();
// a.Count();
// }
// where the 'CreateIEnumerable()' is visited again in the loop.
// In this case, reset the linked 'IEnumerable' entity.
SetAbstractValue(GlobalEntity, GlobalState.RemoveTrackedDeferredTypeEntity(deferredTypeCreationEntity));
}
base.SetAbstractValueForAssignment(targetAnalysisEntity, assignedValueOperation, assignedValue);
}