private static void RemoveLastEmptyStatement(DoStatement dostat, Statement stat)
{
if (stat == dostat.GetFirst())
{
BasicBlockStatement bstat = new BasicBlockStatement(new BasicBlock(DecompilerContext
.GetCounterContainer().GetCounterAndIncrement(CounterContainer.Statement_Counter
)));
bstat.SetExprents(new List <Exprent>());
dostat.ReplaceStatement(stat, bstat);
}
else
{
foreach (StatEdge edge in stat.GetAllPredecessorEdges())
{
edge.GetSource().ChangeEdgeType(Statement.Direction_Forward, edge, StatEdge.Type_Continue
);
stat.RemovePredecessor(edge);
edge.GetSource().ChangeEdgeNode(Statement.Direction_Forward, edge, dostat);
dostat.AddPredecessor(edge);
dostat.AddLabeledEdge(edge);
}
// parent is a sequence statement
stat.GetParent().GetStats().RemoveWithKey(stat.id);
}
}
private static bool MatchWhile(DoStatement stat)
{
// search for an if condition at the entrance of the loop
Statement first = stat.GetFirst();
while (first.type == Statement.Type_Sequence)
{
first = first.GetFirst();
}
// found an if statement
if (first.type == Statement.Type_If)
{
IfStatement firstif = (IfStatement)first;
if ((firstif.GetFirst().GetExprents().Count == 0))
{
if (firstif.iftype == IfStatement.Iftype_If)
{
if (firstif.GetIfstat() == null)
{
StatEdge ifedge = firstif.GetIfEdge();
if (IsDirectPath(stat, ifedge.GetDestination()))
{
// exit condition identified
stat.SetLooptype(DoStatement.Loop_While);
// negate condition (while header)
IfExprent ifexpr = (IfExprent)firstif.GetHeadexprent().Copy();
ifexpr.NegateIf();
stat.SetConditionExprent(ifexpr.GetCondition());
// remove edges
firstif.GetFirst().RemoveSuccessor(ifedge);
firstif.RemoveSuccessor(firstif.GetAllSuccessorEdges()[0]);
if ((stat.GetAllSuccessorEdges().Count == 0))
{
ifedge.SetSource(stat);
if (ifedge.closure == stat)
{
ifedge.closure = stat.GetParent();
}
stat.AddSuccessor(ifedge);
}
// remove empty if statement as it is now part of the loop
if (firstif == stat.GetFirst())
{
BasicBlockStatement bstat = new BasicBlockStatement(new BasicBlock(DecompilerContext
.GetCounterContainer().GetCounterAndIncrement(CounterContainer.Statement_Counter
)));
bstat.SetExprents(new List <Exprent>());
stat.ReplaceStatement(firstif, bstat);
}
else
{
// precondition: sequence must contain more than one statement!
Statement sequence = firstif.GetParent();
sequence.GetStats().RemoveWithKey(firstif.id);
sequence.SetFirst(sequence.GetStats()[0]);
}
return(true);
}
}
else
{
StatEdge elseedge = firstif.GetAllSuccessorEdges()[0];
if (IsDirectPath(stat, elseedge.GetDestination()))
{
// exit condition identified
stat.SetLooptype(DoStatement.Loop_While);
// no need to negate the while condition
stat.SetConditionExprent(((IfExprent)firstif.GetHeadexprent().Copy()).GetCondition
());
// remove edges
StatEdge ifedge = firstif.GetIfEdge();
firstif.GetFirst().RemoveSuccessor(ifedge);
firstif.RemoveSuccessor(elseedge);
if ((stat.GetAllSuccessorEdges().Count == 0))
{
elseedge.SetSource(stat);
if (elseedge.closure == stat)
{
elseedge.closure = stat.GetParent();
}
stat.AddSuccessor(elseedge);
}
if (firstif.GetIfstat() == null)
{
BasicBlockStatement bstat = new BasicBlockStatement(new BasicBlock(DecompilerContext
.GetCounterContainer().GetCounterAndIncrement(CounterContainer.Statement_Counter
)));
bstat.SetExprents(new List <Exprent>());
ifedge.SetSource(bstat);
bstat.AddSuccessor(ifedge);
stat.ReplaceStatement(firstif, bstat);
}
else
{
// replace the if statement with its content
first.GetParent().ReplaceStatement(first, firstif.GetIfstat());
// lift closures
foreach (StatEdge prededge in elseedge.GetDestination().GetPredecessorEdges(StatEdge
.Type_Break))
{
if (stat.ContainsStatementStrict(prededge.closure))
{
stat.AddLabeledEdge(prededge);
}
}
LabelHelper.LowClosures(stat);
}
return(true);
}
}
}
}
}
return(false);
}