/// <summary>
/// Gets the dominated nodes of the condition successor, only if they can form a legal block for the if construct.
/// </summary>
/// <param name="dominatorTree"></param>
/// <param name="conditionSuccessor"></param>
/// <returns>On success - a set of the nodes fo the block. Otherwise it returns null.</returns>
private HashSet<ILogicalConstruct> GetBlockBody(DominatorTree dominatorTree, ILogicalConstruct conditionSuccessor, ConditionLogicalConstruct theCondition)
{
if(conditionSuccessor == dominatorTree.RootConstruct) //Corner case - the successor cannot be the entry of the construct.
{
return null;
}
HashSet<ILogicalConstruct> body = null;
if(conditionSuccessor.AllPredecessors.Count == 1) //The condition successor must have only one predecessor - the condition.
{
body = new HashSet<ILogicalConstruct>();
foreach (ILogicalConstruct node in dominatorTree.GetDominatedNodes(conditionSuccessor))
{
if (node == theCondition)
{
return null;
}
body.Add(node);
}
}
return body;
}
private Dictionary<ILogicalConstruct, HashSet<ISingleEntrySubGraph>> GetValidCases(DominatorTree dominatorTree, ILogicalConstruct switchCFGBlock)
{
Dictionary<ILogicalConstruct, HashSet<ISingleEntrySubGraph>> caseEntriesToDominatedNodesMap = new Dictionary<ILogicalConstruct, HashSet<ISingleEntrySubGraph>>();
HashSet<ISingleEntrySubGraph> legalPredecessors = new HashSet<ISingleEntrySubGraph>();
legalPredecessors.Add(switchCFGBlock);
foreach (ILogicalConstruct successor in switchCFGBlock.SameParentSuccessors)
{
if (successor != switchCFGBlock && dominatorTree.GetImmediateDominator(successor) == switchCFGBlock)
{
HashSet<ISingleEntrySubGraph> dominatedNodes = dominatorTree.GetDominatedNodes(successor);
caseEntriesToDominatedNodesMap.Add(successor, dominatedNodes);
legalPredecessors.UnionWith(dominatedNodes);
}
}
DFSTree dfsTree = DFSTBuilder.BuildTree(switchCFGBlock.Parent, switchCFGBlock);
List<ILogicalConstruct> orderedCaseEntries =
new List<ILogicalConstruct>(dfsTree.ReversePostOrder.Select(node => node.Construct as ILogicalConstruct).Where(construct => caseEntriesToDominatedNodesMap.ContainsKey(construct)));
bool changed;
do
{
changed = false;
foreach (ILogicalConstruct caseEntry in orderedCaseEntries)
{
HashSet<ISingleEntrySubGraph> dominatedNodes;
if (caseEntriesToDominatedNodesMap.TryGetValue(caseEntry, out dominatedNodes) && !IsCaseValid(caseEntry, legalPredecessors))
{
legalPredecessors.ExceptWith(dominatedNodes);
caseEntriesToDominatedNodesMap.Remove(caseEntry);
changed = true;
}
}
} while (changed);
return caseEntriesToDominatedNodesMap;
}
