85 lines
2.3 KiB
C#
85 lines
2.3 KiB
C#
using System.Collections.Generic;
|
||
using System.Linq;
|
||
|
||
namespace dnlib.IR {
|
||
class CFG {
|
||
|
||
private readonly List<IRBasicBlock> _bbs;
|
||
private readonly List<IRExceptionHandler> _exHandlers;
|
||
|
||
public CFG(List<IRBasicBlock> bbs, List<IRExceptionHandler> exHandlers) {
|
||
_bbs = bbs;
|
||
_exHandlers = exHandlers;
|
||
}
|
||
|
||
|
||
|
||
|
||
|
||
private void BasicBlockForwardDFS(IRBasicBlock bb, Dictionary<IRBasicBlock, StronglyConnectedComponents> bb2scc, HashSet<IRBasicBlock> visited, Stack<IRBasicBlock> stack) {
|
||
if (!bb2scc.TryGetValue(bb, out var scc)) {
|
||
scc = new StronglyConnectedComponents();
|
||
scc.AddBlock(bb);
|
||
bb2scc.Add(bb, scc);
|
||
}
|
||
|
||
// existing cycle
|
||
if (!visited.Add(bb)) {
|
||
foreach (var prevBb in stack) {
|
||
if (prevBb == bb) {
|
||
break;
|
||
}
|
||
scc.Merge(bb2scc[prevBb], bb2scc);
|
||
}
|
||
return;
|
||
}
|
||
|
||
stack.Push(bb);
|
||
foreach (var next in bb.OutboundBasicBlocks) {
|
||
BasicBlockForwardDFS(next, bb2scc, visited, stack);
|
||
}
|
||
stack.Pop();
|
||
}
|
||
|
||
private void ComputeSccFowardFlows(Dictionary<IRBasicBlock, StronglyConnectedComponents> bb2scc) {
|
||
var csss = new HashSet<StronglyConnectedComponents>();
|
||
foreach (var sc in bb2scc.Values) {
|
||
if (csss.Add(sc)) {
|
||
sc.InitOutboundSccs(bb2scc);
|
||
}
|
||
}
|
||
}
|
||
|
||
private readonly Dictionary<IRBasicBlock, StronglyConnectedComponents> _bb2scc = new Dictionary<IRBasicBlock, StronglyConnectedComponents>();
|
||
|
||
public StronglyConnectedComponents GetScc(IRBasicBlock bb) {
|
||
return _bb2scc[bb];
|
||
}
|
||
|
||
public void ComputeControlFlows() {
|
||
var visited = new HashSet<IRBasicBlock>();
|
||
var stack = new Stack<IRBasicBlock>();
|
||
BasicBlockForwardDFS(_bbs[0], _bb2scc, visited, stack);
|
||
|
||
foreach (var ex in _exHandlers) {
|
||
//if (ex.TryStart != null) {
|
||
// BasicBlockForwardDFS(ex.TryStart, bb2scc, visited, stack);
|
||
//}
|
||
if (ex.HandlerStart != null) {
|
||
BasicBlockForwardDFS(ex.HandlerStart, _bb2scc, visited, stack);
|
||
}
|
||
if (ex.FilterStart != null) {
|
||
BasicBlockForwardDFS(ex.FilterStart, _bb2scc, visited, stack);
|
||
}
|
||
}
|
||
|
||
ComputeSccFowardFlows(_bb2scc);
|
||
}
|
||
|
||
|
||
|
||
// 要计算多个基本块（BasicBlocks）的共同最近的前驱基本块（即最近公共祖先，LCA，Lowest Common Ancestor），你可以使用以下方法。这里假设你有一个控制流图（CFG），其中每个基本块是一个节点，边代表控制流。
|
||
|
||
}
|
||
}
|