public FlowGraphNode Split(long labelValue, long prevLabelValue)
{
if (nodes.ContainsKey(labelValue))
{
return(nodes[labelValue]);
}
FlowGraphNode n1 = Find(labelValue);
if (n1 == null)
{
return(null);
}
FlowGraphNode n2 = NewNode(labelValue);
//断开n1与它的后继并将之添加为n2的后继
FlowGraphNode[] n1s = new FlowGraphNode[n1.NextNodes.Count];
n1.NextNodes.CopyTo(n1s, 0);
foreach (FlowGraphNode n in n1s)
{
n1.DelNext(n);
n2.AddNext(n);
}
//将n2添加为n1的后继
n1.AddNext(n2);
//设置n2的结束标签为n1的结束标签，若n1的结束标签不大于n2的开始标签则不调整n2的结束标签
if (n1.EndLabelValue > n2.LabelValue)
{
n2.EndLabelValue = n1.EndLabelValue;
}
//设置n1的结束标签为分离标签的前一个标签
n1.EndLabelValue = prevLabelValue;
return(n2);
}
private void BuildFlowGraph()
{
flowGraph = new FlowGraph();
FlowGraphNode curNode = null;
FlowGraphNode prevNode = null;
bool nextIsBlock = true;
for (int i = 0; i < ilLines.Count; i++)
{
IlIns il = ilLines.Values[i];
if (nextIsBlock)
{
nextIsBlock = false;
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
curNode = node;
if (prevNode != null)
{
prevNode.AddNext(node);
}
}
else
{
if (flowGraph.IsNode(il.LabelValue))
{
FlowGraphNode node = flowGraph[il.LabelValue];
curNode.EndLabelValue = GetPrevIlLabelValue(il.LabelValue);
curNode.AddNext(node);
curNode = node;
}
}
IlOpcode op0 = IlOpcodes.GetEH(il.Opcode);
if (op0 != IlOpcode.Prefixref)
{
switch (op0)
{
case IlOpcode.TRY:
{
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
if (curNode != null)
{
curNode.AddNext(node);
}
curNode = node;
}
break;
case IlOpcode.CATCH:
{
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
curNode = node;
}
break;
case IlOpcode.FINALLY:
{
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
curNode = node;
}
break;
case IlOpcode.FILTER:
{
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
curNode = node;
}
break;
case IlOpcode.FAULT:
{
FlowGraphNode node = flowGraph.NewNode(il.LabelValue);
curNode = node;
}
break;
case IlOpcode.ENDTRY:
case IlOpcode.ENDCATCH:
case IlOpcode.ENDFINALLY:
case IlOpcode.ENDFILTER:
case IlOpcode.ENDFAULT:
{
curNode.EndLabelValue = il.LabelValue;
prevNode = null;
nextIsBlock = true;
}
break;
}
}
else
{
OpCode op = IlOpcodes.Get(il.Opcode);
switch ((IlOpcode)op.Value)
{
case IlOpcode.Br:
case IlOpcode.Br_S:
{
long val = IlIns.LabelToValue(il.Value);
FlowGraphNode node = null;
if (val > il.LabelValue)
{
node = flowGraph.NewNode(val);
curNode.AddNext(node);
}
else
{
long prevVal = GetPrevIlLabelValue(val);
FlowGraphNode d = flowGraph.Find(val);
node = flowGraph.Split(val, prevVal);
if (curNode != d)
{
curNode.AddNext(node);
}
else
{
node.AddNext(node);
curNode = node;
}
}
curNode.EndLabelValue = il.LabelValue;
prevNode = null;
nextIsBlock = true;
}
break;
case IlOpcode.Brtrue:
case IlOpcode.Brfalse:
case IlOpcode.Brtrue_S:
case IlOpcode.Brfalse_S:
case IlOpcode.Beq_S:
case IlOpcode.Bge_S:
case IlOpcode.Bgt_S:
case IlOpcode.Ble_S:
case IlOpcode.Blt_S:
case IlOpcode.Bne_Un_S:
case IlOpcode.Bge_Un_S:
case IlOpcode.Bgt_Un_S:
case IlOpcode.Ble_Un_S:
case IlOpcode.Blt_Un_S:
case IlOpcode.Beq:
case IlOpcode.Bge:
case IlOpcode.Bgt:
case IlOpcode.Ble:
case IlOpcode.Blt:
case IlOpcode.Bne_Un:
case IlOpcode.Bge_Un:
case IlOpcode.Bgt_Un:
case IlOpcode.Ble_Un:
case IlOpcode.Blt_Un:
{
long val = IlIns.LabelToValue(il.Value);
FlowGraphNode node = null;
if (val > il.LabelValue)
{
node = flowGraph.NewNode(val);
curNode.AddNext(node);
}
else
{
long prevVal = GetPrevIlLabelValue(val);
FlowGraphNode d = flowGraph.Find(val);
node = flowGraph.Split(val, prevVal);
if (curNode != d)
{
curNode.AddNext(node);
}
else
{
node.AddNext(node);
curNode = node;
}
}
curNode.EndLabelValue = il.LabelValue;
prevNode = curNode;
nextIsBlock = true;
}
break;
case IlOpcode.Switch:
{
SwitchOperand opVal = il.Operand as SwitchOperand;
foreach (string label in opVal.Labels)
{
long val = IlIns.LabelToValue(label);
FlowGraphNode node = null;
if (val > il.LabelValue)
{
node = flowGraph.NewNode(val);
curNode.AddNext(node);
}
else
{
long prevVal = GetPrevIlLabelValue(val);
FlowGraphNode d = flowGraph.Find(val);
node = flowGraph.Split(val, prevVal);
if (curNode != d)
{
curNode.AddNext(node);
}
else
{
node.AddNext(node);
curNode = node;
}
}
}
curNode.EndLabelValue = il.LabelValue;
prevNode = curNode;
nextIsBlock = true;
}
break;
case IlOpcode.Ret:
case IlOpcode.Break:
case IlOpcode.Throw:
case IlOpcode.Rethrow:
case IlOpcode.Leave:
case IlOpcode.Leave_S:
case IlOpcode.Endfilter:
case IlOpcode.Endfinally:
{
curNode.EndLabelValue = il.LabelValue;
prevNode = null;
nextIsBlock = true;
}
break;
}
}
}
}
public void Combine(FlowGraphNode n1, FlowGraphNode n2)
{
if (n1 == null || n2 == null)
{
return;
}
if (n2.PrevNodes.Count == 1 && n2.PrevNodes[0] == n1 && n1.NextNodes.Count == 1 && n1.NextNodes[0] == n2)//合并条件：n2必须是n1的唯一后继，n1必须是n2的唯一前导
{
//断开n1与n2的关联
n1.DelNext(n2);
//断开n2与其后继的关联，并将其后继添加为n1的后继
FlowGraphNode[] n2s = new FlowGraphNode[n2.NextNodes.Count];
n2.NextNodes.CopyTo(n2s, 0);
foreach (FlowGraphNode n in n2s)
{
n2.DelNext(n);
n1.AddNext(n);
}
//n1的结束标签改为n2的结束标签
n1.EndLabelValue = n2.EndLabelValue;
//删除流图对n2的记忆
nodes.Remove(n2.LabelValue);
accessedNodes.Remove(n2);
unaccessedNodes.Remove(n2);
bool inStack = false;
foreach (FlowGraphNode n in iterateStack)
{
if (n == n2)
{
inStack = true;
break;
}
}
if (inStack)
{
FlowGraphNode[] ns = iterateStack.ToArray();
iterateStack.Clear();
for (int i = ns.Length - 1; i >= 0; i--)
{
if (ns[i] != n2)
{
iterateStack.Push(ns[i]);
}
}
}
if (curNode == n2)
{
curNode = n1;
//设置n1为已访问
AccessNode(n1);
//删除迭代器栈里的n1
inStack = false;
foreach (FlowGraphNode n in iterateStack)
{
if (n == n1)
{
inStack = true;
break;
}
}
if (inStack)
{
FlowGraphNode[] ns = iterateStack.ToArray();
iterateStack.Clear();
for (int i = ns.Length - 1; i >= 0; i--)
{
if (ns[i] != n1)
{
iterateStack.Push(ns[i]);
}
}
}
}
}
}