private static bool CollapseIfElse(IfHelper.IfNode rtnode)
{
if (rtnode.edgetypes[0] == 0)
{
IfHelper.IfNode ifbranch = rtnode.succs[0];
if (ifbranch.succs.Count == 2)
{
// if-else branch
if (ifbranch.succs[0].value == rtnode.succs[1].value)
{
IfStatement ifparent = (IfStatement)rtnode.value;
IfStatement ifchild = (IfStatement)ifbranch.value;
if ((ifchild.GetFirst().GetExprents().Count == 0))
{
ifparent.GetFirst().RemoveSuccessor(ifparent.GetIfEdge());
ifchild.GetFirst().RemoveSuccessor(ifchild.GetIfEdge());
ifparent.GetStats().RemoveWithKey(ifchild.id);
if (ifbranch.edgetypes[1] == 1 && ifbranch.edgetypes[0] == 1)
{
// target null
ifparent.SetIfstat(null);
StatEdge ifedge = ifchild.GetAllSuccessorEdges()[0];
ifchild.RemoveSuccessor(ifedge);
ifedge.SetSource(ifparent.GetFirst());
ifparent.GetFirst().AddSuccessor(ifedge);
ifparent.SetIfEdge(ifedge);
}
else
{
throw new Exception("inconsistent if structure!");
}
// merge if conditions
IfExprent statexpr = ifparent.GetHeadexprent();
List <Exprent> lstOperands = new List <Exprent>();
lstOperands.Add(statexpr.GetCondition());
lstOperands.Add(new FunctionExprent(FunctionExprent.Function_Bool_Not, ifchild.GetHeadexprent
().GetCondition(), null));
statexpr.SetCondition(new FunctionExprent(FunctionExprent.Function_Cadd, lstOperands
, null));
statexpr.AddBytecodeOffsets(ifchild.GetHeadexprent().bytecode);
return(true);
}
}
}
}
return(false);
}
public static bool IdentifySecondaryFunctions(Statement stat, VarProcessor varProc
)
{
if (stat.GetExprents() == null)
{
// if(){;}else{...} -> if(!){...}
if (stat.type == Statement.Type_If)
{
IfStatement ifelsestat = (IfStatement)stat;
Statement ifstat = ifelsestat.GetIfstat();
if (ifelsestat.iftype == IfStatement.Iftype_Ifelse && ifstat.GetExprents() != null &&
(ifstat.GetExprents().Count == 0) && ((ifstat.GetAllSuccessorEdges().Count == 0) ||
!ifstat.GetAllSuccessorEdges()[0].@explicit))
{
// move else to the if position
ifelsestat.GetStats().RemoveWithKey(ifstat.id);
ifelsestat.iftype = IfStatement.Iftype_If;
ifelsestat.SetIfstat(ifelsestat.GetElsestat());
ifelsestat.SetElsestat(null);
if ((ifelsestat.GetAllSuccessorEdges().Count == 0) && !(ifstat.GetAllSuccessorEdges
().Count == 0))
{
StatEdge endedge = ifstat.GetAllSuccessorEdges()[0];
ifstat.RemoveSuccessor(endedge);
endedge.SetSource(ifelsestat);
if (endedge.closure != null)
{
ifelsestat.GetParent().AddLabeledEdge(endedge);
}
ifelsestat.AddSuccessor(endedge);
}
ifelsestat.GetFirst().RemoveSuccessor(ifelsestat.GetIfEdge());
ifelsestat.SetIfEdge(ifelsestat.GetElseEdge());
ifelsestat.SetElseEdge(null);
// negate head expression
ifelsestat.SetNegated(!ifelsestat.IsNegated());
ifelsestat.GetHeadexprentList()[0] = ((IfExprent)ifelsestat.GetHeadexprent().Copy
()).NegateIf();
return(true);
}
}
}
bool replaced = true;
while (replaced)
{
replaced = false;
List <object> lstObjects = new List <object>(stat.GetExprents() == null ? (IEnumerable <object>)stat.GetSequentialObjects
() : stat.GetExprents());
for (int i = 0; i < lstObjects.Count; i++)
{
object obj = lstObjects[i];
if (obj is Statement)
{
if (IdentifySecondaryFunctions((Statement)obj, varProc))
{
replaced = true;
break;
}
}
else if (obj is Exprent)
{
Exprent retexpr = IdentifySecondaryFunctions((Exprent)obj, true, varProc);
if (retexpr != null)
{
if (stat.GetExprents() == null)
{
// only head expressions can be replaced!
stat.ReplaceExprent((Exprent)obj, retexpr);
}
else
{
stat.GetExprents()[i] = retexpr;
}
replaced = true;
break;
}
}
}
}
return(false);
}
private static void MatchDoWhile(DoStatement stat)
{
// search for an if condition at the end of the loop
Statement last = stat.GetFirst();
while (last.type == Statement.Type_Sequence)
{
last = last.GetStats().GetLast();
}
if (last.type == Statement.Type_If)
{
IfStatement lastif = (IfStatement)last;
if (lastif.iftype == IfStatement.Iftype_If && lastif.GetIfstat() == null)
{
StatEdge ifedge = lastif.GetIfEdge();
StatEdge elseedge = lastif.GetAllSuccessorEdges()[0];
if ((ifedge.GetType() == StatEdge.Type_Break && elseedge.GetType() == StatEdge.Type_Continue &&
elseedge.closure == stat && IsDirectPath(stat, ifedge.GetDestination())) ||
(ifedge.GetType() == StatEdge.Type_Continue && elseedge.GetType() == StatEdge.Type_Break &&
ifedge.closure == stat && IsDirectPath(stat, elseedge.GetDestination())))
{
HashSet <Statement> set = stat.GetNeighboursSet(StatEdge.Type_Continue, Statement.
Direction_Backward);
set.Remove(last);
if (!(set.Count == 0))
{
return;
}
stat.SetLooptype(DoStatement.Loop_Dowhile);
IfExprent ifexpr = (IfExprent)lastif.GetHeadexprent().Copy();
if (ifedge.GetType() == StatEdge.Type_Break)
{
ifexpr.NegateIf();
}
stat.SetConditionExprent(ifexpr.GetCondition());
lastif.GetFirst().RemoveSuccessor(ifedge);
lastif.RemoveSuccessor(elseedge);
// remove empty if
if ((lastif.GetFirst().GetExprents().Count == 0))
{
RemoveLastEmptyStatement(stat, lastif);
}
else
{
lastif.SetExprents(lastif.GetFirst().GetExprents());
StatEdge newedge = new StatEdge(StatEdge.Type_Continue, lastif, stat);
lastif.AddSuccessor(newedge);
stat.AddLabeledEdge(newedge);
}
if ((stat.GetAllSuccessorEdges().Count == 0))
{
StatEdge edge = elseedge.GetType() == StatEdge.Type_Continue ? ifedge : elseedge;
edge.SetSource(stat);
if (edge.closure == stat)
{
edge.closure = stat.GetParent();
}
stat.AddSuccessor(edge);
}
}
}
}
}
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);
}
// FIXME: rewrite the entire method!!! keep in mind finally exits!!
private static bool ReorderIf(IfStatement ifstat)
{
if (ifstat.iftype == IfStatement.Iftype_Ifelse)
{
return(false);
}
bool ifdirect;
bool elsedirect;
bool noifstat = false;
bool noelsestat;
bool ifdirectpath = false;
bool elsedirectpath = false;
Statement parent = ifstat.GetParent();
Statement from = parent.type == Statement.Type_Sequence ? parent : ifstat;
Statement next = GetNextStatement(from);
if (ifstat.GetIfstat() == null)
{
noifstat = true;
ifdirect = ifstat.GetIfEdge().GetType() == StatEdge.Type_Finallyexit || MergeHelper
.IsDirectPath(from, ifstat.GetIfEdge().GetDestination());
}
else
{
List <StatEdge> lstSuccs = ifstat.GetIfstat().GetAllSuccessorEdges();
ifdirect = !(lstSuccs.Count == 0) && lstSuccs[0].GetType() == StatEdge.Type_Finallyexit ||
HasDirectEndEdge(ifstat.GetIfstat(), from);
}
Statement last = parent.type == Statement.Type_Sequence ? parent.GetStats().GetLast
() : ifstat;
noelsestat = (last == ifstat);
elsedirect = !(last.GetAllSuccessorEdges().Count == 0) && last.GetAllSuccessorEdges
()[0].GetType() == StatEdge.Type_Finallyexit || HasDirectEndEdge(last, from);
if (!noelsestat && ExistsPath(ifstat, ifstat.GetAllSuccessorEdges()[0].GetDestination
()))
{
return(false);
}
if (!ifdirect && !noifstat)
{
ifdirectpath = ExistsPath(ifstat, next);
}
if (!elsedirect && !noelsestat)
{
SequenceStatement sequence = (SequenceStatement)parent;
for (int i = sequence.GetStats().Count - 1; i >= 0; i--)
{
Statement sttemp = sequence.GetStats()[i];
if (sttemp == ifstat)
{
break;
}
else if (elsedirectpath = ExistsPath(sttemp, next))
{
break;
}
}
}
if ((ifdirect || ifdirectpath) && (elsedirect || elsedirectpath) && !noifstat &&
!noelsestat)
{
// if - then - else
SequenceStatement sequence = (SequenceStatement)parent;
// build and cut the new else statement
List <Statement> lst = new List <Statement>();
for (int i = sequence.GetStats().Count - 1; i >= 0; i--)
{
Statement sttemp = sequence.GetStats()[i];
if (sttemp == ifstat)
{
break;
}
else
{
lst.Add(0, sttemp);
}
}
Statement stelse;
if (lst.Count == 1)
{
stelse = lst[0];
}
else
{
stelse = new SequenceStatement(lst);
stelse.SetAllParent();
}
ifstat.RemoveSuccessor(ifstat.GetAllSuccessorEdges()[0]);
foreach (Statement st in lst)
{
sequence.GetStats().RemoveWithKey(st.id);
}
StatEdge elseedge = new StatEdge(StatEdge.Type_Regular, ifstat.GetFirst(), stelse
);
ifstat.GetFirst().AddSuccessor(elseedge);
ifstat.SetElsestat(stelse);
ifstat.SetElseEdge(elseedge);
ifstat.GetStats().AddWithKey(stelse, stelse.id);
stelse.SetParent(ifstat);
// if(next.type != Statement.TYPE_DUMMYEXIT && (ifdirect || elsedirect)) {
// StatEdge breakedge = new StatEdge(StatEdge.TYPE_BREAK, ifstat, next);
// sequence.addLabeledEdge(breakedge);
// ifstat.addSuccessor(breakedge);
// }
ifstat.iftype = IfStatement.Iftype_Ifelse;
}
else if (ifdirect && (!elsedirect || (noifstat && !noelsestat)))
{
// if - then
// negate the if condition
IfExprent statexpr = ifstat.GetHeadexprent();
statexpr.SetCondition(new FunctionExprent(FunctionExprent.Function_Bool_Not, statexpr
.GetCondition(), null));
if (noelsestat)
{
StatEdge ifedge = ifstat.GetIfEdge();
StatEdge elseedge = ifstat.GetAllSuccessorEdges()[0];
if (noifstat)
{
ifstat.GetFirst().RemoveSuccessor(ifedge);
ifstat.RemoveSuccessor(elseedge);
ifedge.SetSource(ifstat);
elseedge.SetSource(ifstat.GetFirst());
ifstat.AddSuccessor(ifedge);
ifstat.GetFirst().AddSuccessor(elseedge);
ifstat.SetIfEdge(elseedge);
}
else
{
Statement ifbranch = ifstat.GetIfstat();
SequenceStatement newseq = new SequenceStatement(Sharpen.Arrays.AsList(ifstat, ifbranch
));
ifstat.GetFirst().RemoveSuccessor(ifedge);
ifstat.GetStats().RemoveWithKey(ifbranch.id);
ifstat.SetIfstat(null);
ifstat.RemoveSuccessor(elseedge);
elseedge.SetSource(ifstat.GetFirst());
ifstat.GetFirst().AddSuccessor(elseedge);
ifstat.SetIfEdge(elseedge);
ifstat.GetParent().ReplaceStatement(ifstat, newseq);
newseq.SetAllParent();
ifstat.AddSuccessor(new StatEdge(StatEdge.Type_Regular, ifstat, ifbranch));
}
}
else
{
SequenceStatement sequence = (SequenceStatement)parent;
// build and cut the new else statement
List <Statement> lst = new List <Statement>();
for (int i = sequence.GetStats().Count - 1; i >= 0; i--)
{
Statement sttemp = sequence.GetStats()[i];
if (sttemp == ifstat)
{
break;
}
else
{
lst.Add(0, sttemp);
}
}
Statement stelse;
if (lst.Count == 1)
{
stelse = lst[0];
}
else
{
stelse = new SequenceStatement(lst);
stelse.SetAllParent();
}
ifstat.RemoveSuccessor(ifstat.GetAllSuccessorEdges()[0]);
foreach (Statement st in lst)
{
sequence.GetStats().RemoveWithKey(st.id);
}
if (noifstat)
{
StatEdge ifedge = ifstat.GetIfEdge();
ifstat.GetFirst().RemoveSuccessor(ifedge);
ifedge.SetSource(ifstat);
ifstat.AddSuccessor(ifedge);
}
else
{
Statement ifbranch = ifstat.GetIfstat();
ifstat.GetFirst().RemoveSuccessor(ifstat.GetIfEdge());
ifstat.GetStats().RemoveWithKey(ifbranch.id);
ifstat.AddSuccessor(new StatEdge(StatEdge.Type_Regular, ifstat, ifbranch));
sequence.GetStats().AddWithKey(ifbranch, ifbranch.id);
ifbranch.SetParent(sequence);
}
StatEdge newifedge = new StatEdge(StatEdge.Type_Regular, ifstat.GetFirst(), stelse
);
ifstat.GetFirst().AddSuccessor(newifedge);
ifstat.SetIfstat(stelse);
ifstat.SetIfEdge(newifedge);
ifstat.GetStats().AddWithKey(stelse, stelse.id);
stelse.SetParent(ifstat);
}
}
else
{
return(false);
}
return(true);
}
private static bool CollapseIfIf(IfHelper.IfNode rtnode)
{
if (rtnode.edgetypes[0] == 0)
{
IfHelper.IfNode ifbranch = rtnode.succs[0];
if (ifbranch.succs.Count == 2)
{
// if-if branch
if (ifbranch.succs[1].value == rtnode.succs[1].value)
{
IfStatement ifparent = (IfStatement)rtnode.value;
IfStatement ifchild = (IfStatement)ifbranch.value;
Statement ifinner = ifbranch.succs[0].value;
if ((ifchild.GetFirst().GetExprents().Count == 0))
{
ifparent.GetFirst().RemoveSuccessor(ifparent.GetIfEdge());
ifchild.RemoveSuccessor(ifchild.GetAllSuccessorEdges()[0]);
ifparent.GetStats().RemoveWithKey(ifchild.id);
if (ifbranch.edgetypes[0] == 1)
{
// target null
ifparent.SetIfstat(null);
StatEdge ifedge = ifchild.GetIfEdge();
ifchild.GetFirst().RemoveSuccessor(ifedge);
ifedge.SetSource(ifparent.GetFirst());
if (ifedge.closure == ifchild)
{
ifedge.closure = null;
}
ifparent.GetFirst().AddSuccessor(ifedge);
ifparent.SetIfEdge(ifedge);
}
else
{
ifchild.GetFirst().RemoveSuccessor(ifchild.GetIfEdge());
StatEdge ifedge = new StatEdge(StatEdge.Type_Regular, ifparent.GetFirst(), ifinner
);
ifparent.GetFirst().AddSuccessor(ifedge);
ifparent.SetIfEdge(ifedge);
ifparent.SetIfstat(ifinner);
ifparent.GetStats().AddWithKey(ifinner, ifinner.id);
ifinner.SetParent(ifparent);
if (!(ifinner.GetAllSuccessorEdges().Count == 0))
{
StatEdge edge = ifinner.GetAllSuccessorEdges()[0];
if (edge.closure == ifchild)
{
edge.closure = null;
}
}
}
// merge if conditions
IfExprent statexpr = ifparent.GetHeadexprent();
List <Exprent> lstOperands = new List <Exprent>();
lstOperands.Add(statexpr.GetCondition());
lstOperands.Add(ifchild.GetHeadexprent().GetCondition());
statexpr.SetCondition(new FunctionExprent(FunctionExprent.Function_Cadd, lstOperands
, null));
statexpr.AddBytecodeOffsets(ifchild.GetHeadexprent().bytecode);
return(true);
}
}
}
}
return(false);
}