Label is not reference counted object anymore, it is just a string. During transform we in two passes - find all live labels - remove all dead ones (the rest).

Decompiler.csproj

@@ -44,7 +44,6 @@
   <ItemGroup>
     <Folder Include="src" />
     <Folder Include="src\ControlFlow" />
-    <Folder Include="src\MyAst" />
     <Folder Include="src\Transforms" />
     <Folder Include="src\Transforms\Ast" />
     <Compile Include="src\AssemblyInfo.cs" />
@@ -62,8 +61,6 @@
     <Compile Include="src\ControlFlow\Node-Structure.cs" />
     <Compile Include="src\MainForm.cs" />
     <Compile Include="src\MainForm.Designer.cs" />
-    <Compile Include="src\MyAst\MyGotoStatement.cs" />
-    <Compile Include="src\MyAst\MyLabelStatement.cs" />
     <Compile Include="src\Options.cs" />
     <Compile Include="src\Program.cs" />
     <Compile Include="src\ByteCode.StackAnalysis.cs" />

src/AstMetodBodyBuilder.cs

@@ -77,7 +77,7 @@ namespace Decompiler
 				yield return MakeComment("// " + node.Description);
 			}
 			
-			yield return new Ast.MyLabelStatement(node.Label);
+			yield return new Ast.LabelStatement(node.Label);
 			
 			if (node is BasicBlock) {
 				foreach(StackExpression expr in ((BasicBlock)node).Body) {
@@ -86,7 +86,7 @@ namespace Decompiler
 				Node fallThroughNode = ((BasicBlock)node).FallThroughBasicBlock;
 				// If there is default branch and it is not the following node
 				if (fallThroughNode != null) {
-					yield return Ast.MyGotoStatement.Create(node, fallThroughNode);
+					yield return MakeBranchCommand(node, fallThroughNode);
 				}
 			} else if (node is AcyclicGraph) {
 				Ast.BlockStatement blockStatement = new Ast.BlockStatement();
@@ -107,7 +107,7 @@ namespace Decompiler
 				}
 			} else if (node is ConditionalNode) {
 				ConditionalNode conditionalNode = (ConditionalNode)node;
-				yield return new Ast.MyLabelStatement(conditionalNode.Condition.Label);
+				yield return new Ast.LabelStatement(conditionalNode.Condition.Label);
 				Ast.Statement lastStatement = null;
 				foreach(StackExpression expr in conditionalNode.Condition.Body) {
 					lastStatement = TransformExpression(expr);
@@ -121,7 +121,7 @@ namespace Decompiler
 				
 				Ast.BlockStatement trueBlock = new Ast.BlockStatement();
 				// The block entry code
-				trueBlock.Children.Add(Ast.MyGotoStatement.Create(node, conditionalNode.Condition.FallThroughBasicBlock));
+				trueBlock.Children.Add(MakeBranchCommand(node, conditionalNode.Condition.FallThroughBasicBlock));
 				// Sugested content
 				trueBlock.Children.AddRange(TransformNode(conditionalNode.TrueBody));
 				ifElseStmt.TrueStatement.Add(trueBlock);
@@ -178,6 +178,23 @@ namespace Decompiler
 			return new Ast.ExpressionStatement(new PrimitiveExpression(text, text));
 		}
 		
+		public static Ast.Statement MakeBranchCommand(Node contextNode, Node targetNode)
+		{
+			// Propagate target up to the top most scope
+			while (targetNode.Parent != null && targetNode.Parent.HeadChild == targetNode) {
+				targetNode = targetNode.Parent;
+			}
+			// If branches to the start of encapsulating loop
+			if (contextNode.Parent is Loop && targetNode == contextNode.Parent) {
+				return new Ast.ContinueStatement();
+			}
+			// If branches outside the encapsulating loop
+			if (contextNode.Parent is Loop && targetNode == contextNode.Parent.NextNode) {
+				return new Ast.BreakStatement();
+			}
+			return new Ast.GotoStatement(targetNode.Label);
+		}
+		
 		static object MakeCodeDomExpression(MethodDefinition methodDef, StackExpression expr, params Ast.Expression[] args)
 		{
 			List<Ast.Expression> allArgs = new List<Ast.Expression>();
@@ -207,7 +224,7 @@ namespace Decompiler
 			
 			Ast.Statement branchCommand = null;
 			if (operand is ByteCode) {
-				branchCommand = Ast.MyGotoStatement.Create(byteCode.Expression.BasicBlock, ((ByteCode)operand).Expression.BasicBlock);
+				branchCommand = MakeBranchCommand(byteCode.Expression.BasicBlock, ((ByteCode)operand).Expression.BasicBlock);
 			}
 			
 			switch(opCode.Code) {

src/ControlFlow/Node-Structure.cs

@@ -9,7 +9,7 @@ namespace Decompiler.ControlFlow
 		public static int NextNodeID = 1;
 		
 		int id;
-		NodeLabel label;
+		string label;
 		Node parent;
 		NodeCollection childs = new NodeCollection();
 		
@@ -22,7 +22,7 @@ namespace Decompiler.ControlFlow
 			get { return id; }
 		}
 		
-		public NodeLabel Label {
+		public string Label {
 			get { return label; }
 		}
 		
@@ -151,7 +151,7 @@ namespace Decompiler.ControlFlow
 		protected Node()
 		{
 			this.id = NextNodeID++;
-			this.label = new NodeLabel(this.GetType().Name + "_" + ID);
+			this.label = this.GetType().Name + "_" + ID;
 			this.Childs.Added += delegate(object sender, NodeEventArgs e) {
 				if (e.Node.Parent != null) {
 					throw new Exception("Node is already assigned to other parent");
@@ -230,24 +230,4 @@ namespace Decompiler.ControlFlow
 			return sb.ToString();
 		}
 	}
-	
-	public class NodeLabel
-	{
-		string label;
-		int referenceCount = 0;
-		
-		public string Label {
-			get { return label; }
-		}
-		
-		public int ReferenceCount {
-			get { return referenceCount; }
-			set { referenceCount = value; }
-		}
-		
-		public NodeLabel(string label)
-		{
-			this.label = label;
-		}
-	}
 }

src/MyAst/MyGotoStatement.cs

@@ -1,40 +0,0 @@
-using System;
-
-using Ast = ICSharpCode.NRefactory.Ast;
-using Decompiler.ControlFlow;
-
-namespace ICSharpCode.NRefactory.Ast
-{
-	public class MyGotoStatement: Ast.GotoStatement
-	{
-		NodeLabel nodeLabel;
-		
-		public NodeLabel NodeLabel {
-			get { return nodeLabel; }
-		}
-		
-		public MyGotoStatement(NodeLabel nodeLabel): base(nodeLabel.Label)
-		{
-			this.nodeLabel = nodeLabel;
-			
-			this.nodeLabel.ReferenceCount++;
-		}
-		
-		public static Ast.Statement Create(Node contextNode, Node targetNode)
-		{
-			// Propagate target up to the top most scope
-			while (targetNode.Parent != null && targetNode.Parent.HeadChild == targetNode) {
-				targetNode = targetNode.Parent;
-			}
-			// If branches to the start of encapsulating loop
-			if (contextNode.Parent is Loop && targetNode == contextNode.Parent) {
-				return new Ast.ContinueStatement();
-			}
-			// If branches outside the encapsulating loop
-			if (contextNode.Parent is Loop && targetNode == contextNode.Parent.NextNode) {
-				return new Ast.BreakStatement();
-			}
-			return new Ast.MyGotoStatement(targetNode.Label);
-		}
-	}
-}

src/MyAst/MyLabelStatement.cs

@@ -1,21 +0,0 @@
-using System;
-
-using Ast = ICSharpCode.NRefactory.Ast;
-using Decompiler.ControlFlow;
-
-namespace ICSharpCode.NRefactory.Ast
-{
-	public class MyLabelStatement: Ast.LabelStatement
-	{
-		NodeLabel nodeLabel;
-		
-		public NodeLabel NodeLabel {
-			get { return nodeLabel; }
-		}
-		
-		public MyLabelStatement(NodeLabel nodeLabel): base(nodeLabel.Label)
-		{
-			this.nodeLabel = nodeLabel;
-		}
-	}
-}

src/Transforms/Ast/RemoveDeadLabels.cs

@@ -1,5 +1,5 @@
 using System;
-
+using System.Collections.Generic;
 using Ast = ICSharpCode.NRefactory.Ast;
 using ICSharpCode.NRefactory.Ast;
 using ICSharpCode.NRefactory.Visitors;
@@ -8,12 +8,33 @@ namespace Decompiler.Transforms.Ast
 {
 	public class RemoveDeadLabels: AbstractAstTransformer
 	{
+		List<string> usedLabels = new List<string>();
+		bool collectingUsedLabels;
+		
+		public override object VisitMethodDeclaration(MethodDeclaration methodDeclaration, object data)
+		{
+			collectingUsedLabels = true;
+			base.VisitMethodDeclaration(methodDeclaration, data);
+			collectingUsedLabels = false;
+			base.VisitMethodDeclaration(methodDeclaration, data);
+			return null;
+		}
+		
+		public override object VisitGotoStatement(GotoStatement gotoStatement, object data)
+		{
+			if (collectingUsedLabels) {
+				usedLabels.Add(gotoStatement.Label);
+			}
+			return null;
+		}
+		
 		public override object VisitLabelStatement(LabelStatement labelStatement, object data)
 		{
-			MyLabelStatement myLabel = (MyLabelStatement)labelStatement;
-			if (myLabel.NodeLabel.ReferenceCount == 0) {
+			if (!collectingUsedLabels) {
+				if (!usedLabels.Contains(labelStatement.Label)) {
 					RemoveCurrentNode();
 				}
+			}
 			return null;
 		}
 	}

src/Transforms/Ast/RemoveGotos.cs

@@ -39,10 +39,9 @@ namespace Decompiler.Transforms.Ast
 			if (lastStmt is GotoStatement &&
 			    blockStatement.Parent is IfElseStatement)
 			{
-				MyLabelStatement nextNodeAsLabel = blockStatement.Parent.Next() as MyLabelStatement;
+				LabelStatement nextNodeAsLabel = blockStatement.Parent.Next() as LabelStatement;
 				if (nextNodeAsLabel != null) {
-					if (nextNodeAsLabel.NodeLabel == ((MyGotoStatement)lastStmt).NodeLabel) {
-						((MyGotoStatement)lastStmt).NodeLabel.ReferenceCount--;
+					if (nextNodeAsLabel.Label == ((GotoStatement)lastStmt).Label) {
 						lastStmt.Remove();
 						return null;
 					}
@@ -54,10 +53,8 @@ namespace Decompiler.Transforms.Ast
 		
 		public override object VisitGotoStatement(GotoStatement gotoStatement, object data)
 		{
-			MyGotoStatement myGoto = (MyGotoStatement)gotoStatement;
-			MyLabelStatement followingLabel = myGoto.Next() as MyLabelStatement;
-			if (followingLabel != null && followingLabel.NodeLabel == myGoto.NodeLabel) {
-				myGoto.NodeLabel.ReferenceCount--;
+			LabelStatement followingLabel = gotoStatement.Next() as LabelStatement;
+			if (followingLabel != null && followingLabel.Label == gotoStatement.Label) {
 				RemoveCurrentNode();
 			}
 			return null;

src/Transforms/Ast/RestoreLoop.cs

@@ -27,15 +27,14 @@ namespace Decompiler.Transforms.Ast
 			{
 				IfElseStatement  condition = forStatement.EmbeddedStatement.Children[0] as IfElseStatement;
 				BreakStatement   breakStmt = forStatement.EmbeddedStatement.Children[1] as BreakStatement;
-				MyLabelStatement label     = forStatement.EmbeddedStatement.Children[2] as MyLabelStatement;
+				LabelStatement   label     = forStatement.EmbeddedStatement.Children[2] as LabelStatement;
 				if (condition != null && breakStmt != null && label != null &&
 				    condition.TrueStatement.Count == 1)
 				{
-					MyGotoStatement gotoStmt = condition.TrueStatement[0] as MyGotoStatement;
-					if (gotoStmt != null && gotoStmt.NodeLabel == label.NodeLabel) {
+					GotoStatement gotoStmt = condition.TrueStatement[0] as GotoStatement;
+					if (gotoStmt != null && gotoStmt.Label == label.Label) {
 						condition.Remove();
 						breakStmt.Remove();
-						gotoStmt.NodeLabel.ReferenceCount--;
 						forStatement.Condition = condition.Condition;
 					}
 				}