private void processMergeOperation(MergeOperation operation)
{
CollectComposedValuesVisitor visitor = new CollectComposedValuesVisitor();
ReferenceCollector references = new ReferenceCollector();
foreach (var item in operation.Indexes)
{
Snapshot snapshot = item.Item2;
MemoryIndex index = item.Item1;
MemoryEntry entry = snapshot.Structure.GetMemoryEntry(index);
visitor.VisitMemoryEntry(entry);
MemoryAlias aliases;
if (snapshot.Structure.TryGetAliases(index, out aliases))
{
references.CollectMust(aliases.MustAliasses, snapshot.CallLevel);
references.CollectMay(aliases.MayAliasses, snapshot.CallLevel);
}
else
{
references.InvalidateMust();
}
}
if (references.HasAliases && !operation.IsRoot)
{
if (!operation.IsUndefined && operation.Indexes.Count == 1 && references.HasMustAliases)
{
if (targetSnapshot == operation.Indexes.First().Item2)
{
references.AddMustAlias(operation.Indexes.First().Item1);
}
}
else
{
HashSet <MemoryIndex> referenceIndexes = new HashSet <MemoryIndex>();
foreach (var item in operation.Indexes)
{
MemoryIndex index = item.Item1;
Snapshot snapshot = item.Item2;
if (index != operation.TargetIndex && targetSnapshot == snapshot)
{
referenceIndexes.Add(index);
}
}
references.CollectMay(referenceIndexes, targetSnapshot.CallLevel);
}
}
references.SetAliases(operation.TargetIndex, targetSnapshot, !operation.IsUndefined);
HashSet <Value> values = getValues(operation.TargetIndex, visitor, operation.IsUndefined);
if (operation.IsUndefined)
{
values.Add(targetSnapshot.UndefinedValue);
}
targetSnapshot.Structure.SetMemoryEntry(operation.TargetIndex, new MemoryEntry(values));
}
