Add parent pointers to ILAst

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -87,7 +87,6 @@
     <Compile Include="IL\Instructions\TryCatch.cs" />
     <Compile Include="IL\Instructions\TryFinally.cs" />
     <Compile Include="IL\Instructions\UnaryInstruction.cs" />
-    <Compile Include="IL\Visitors\CountPopInstructionsVisitor.cs" />
     <Compile Include="TypesHierarchyHelpers.cs" />
     <Compile Include="CecilExtensions.cs" />
     <Compile Include="Disassembler\DisassemblerHelpers.cs" />
@@ -148,9 +147,6 @@
   <ItemGroup>
     <Service Include="{508349B6-6B84-4DF5-91F0-309BEEBAD82D}" />
   </ItemGroup>
-  <ItemGroup>
-    <Folder Include="IL\Visitors" />
-  </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.Targets" />
   <Target Name="BeforeBuild">
     <MSBuild Projects="$(MSBuildProjectDirectory)\..\BuildTools\UpdateAssemblyInfo\UpdateAssemblyInfo.csproj" Targets="Build" Properties="Configuration=Debug" />

ICSharpCode.Decompiler/IL/BlockBuilder.cs

@@ -43,6 +43,7 @@ namespace ICSharpCode.Decompiler.IL
 		public BlockContainer CreateBlocks(List<ILInstruction> instructions, BitArray incomingBranches)
 		{
 			currentContainer = new BlockContainer();
+			currentContainer.AddRef(); // mark the root node
 
 			incomingBranches[0] = true;	// see entrypoint as incoming branch
 

ICSharpCode.Decompiler/IL/Instructions.cs

@@ -184,11 +184,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.argument, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.argument.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.argument;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -236,12 +235,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.right, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.left.AcceptVisitor(visitor));
-			value = func(value, this.right.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.left;
+				yield return this.right;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -559,13 +557,12 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.falseInst, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.condition.AcceptVisitor(visitor));
-			value = func(value, this.trueInst.AcceptVisitor(visitor));
-			value = func(value, this.falseInst.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.condition;
+				yield return this.trueInst;
+				yield return this.falseInst;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -614,12 +611,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.body, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.filter.AcceptVisitor(visitor));
-			value = func(value, this.body.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.filter;
+				yield return this.body;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -664,12 +660,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.finallyBlock, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.tryBlock.AcceptVisitor(visitor));
-			value = func(value, this.finallyBlock.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.tryBlock;
+				yield return this.finallyBlock;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -706,12 +701,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.faultBlock, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.tryBlock.AcceptVisitor(visitor));
-			value = func(value, this.faultBlock.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.tryBlock;
+				yield return this.faultBlock;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -921,11 +915,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.value, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.value.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.value;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1205,11 +1198,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.target, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1267,11 +1259,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.target, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1330,12 +1321,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.value, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			value = func(value, this.value.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+				yield return this.value;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1456,11 +1446,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.value, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.value.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.value;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1574,11 +1563,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.target, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1645,12 +1633,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.value, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			value = func(value, this.value.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+				yield return this.value;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1921,11 +1908,10 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.target, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.target.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.target;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
@@ -1979,12 +1965,11 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.index, value);
 			}
 		}
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, this.array.AcceptVisitor(visitor));
-			value = func(value, this.index.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return this.array;
+				yield return this.index;
+			}
 		}
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{

ICSharpCode.Decompiler/IL/Instructions.tt

@@ -540,7 +540,9 @@ namespace ICSharpCode.Decompiler.IL
 					+ "}");
 			}
 			opCode.WriteArguments.Add("output.Write(')');");
-			StringBuilder b = new StringBuilder();
+			StringBuilder b;
+			/*
+			b = new StringBuilder();
 			b.AppendLine("public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)");
 			b.AppendLine("{");
 			b.AppendLine("\tTAccumulate value = initial;");
@@ -553,7 +555,22 @@ namespace ICSharpCode.Decompiler.IL
 			}
 			b.AppendLine("\treturn value;");
 			b.Append("}");
+			opCode.Members.Add(b.ToString());*/
+			
+			b = new StringBuilder();
+			b.AppendLine("public override IEnumerable<ILInstruction> Children {");
+			b.AppendLine("\tget {");
+			foreach (var child in children) {
+				if (child.IsOptional) {
+					b.AppendLine("\t\tif (this." + child.Name + " != null)");
+					b.Append('\t');
+				}
+				b.AppendLine("\t\tyield return this." + child.Name + ";");
+			}
+			b.AppendLine("\t}");
+			b.Append("}");
 			opCode.Members.Add(b.ToString());
+			
 			b = new StringBuilder();
 			b.AppendLine("public override void TransformChildren(ILVisitor<ILInstruction> visitor)");
 			b.AppendLine("{");

ICSharpCode.Decompiler/IL/Instructions/Block.cs

@@ -42,14 +42,9 @@ namespace ICSharpCode.Decompiler.IL
 			output.Unindent();
 			output.WriteLine("}");
 		}
-
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			foreach (var inst in Instructions) {
-				value = func(value, inst.AcceptVisitor(visitor));
-			}
-			return value;
+		
+		public override IEnumerable<ILInstruction> Children {
+			get { return Instructions; }
 		}
 		
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)

ICSharpCode.Decompiler/IL/Instructions/BlockContainer.cs

@@ -52,16 +52,11 @@ namespace ICSharpCode.Decompiler.IL
 			output.Unindent();
 			output.WriteLine("}");
 		}
-
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			foreach (var block in Blocks) {
-				value = func(value, block.AcceptVisitor(visitor));
-			}
-			return value;
+		
+		public override IEnumerable<ILInstruction> Children {
+			get { return Blocks; }
 		}
-
+		
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)
 		{
 			foreach (var block in Blocks) {

ICSharpCode.Decompiler/IL/Instructions/CallInstruction.cs

@@ -69,12 +69,8 @@ namespace ICSharpCode.Decompiler.IL
 			}
 		}
 		
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			foreach (var op in Arguments)
-				value = func(value, op.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get { return Arguments; }
 		}
 		
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)

ICSharpCode.Decompiler/IL/Instructions/ILInstruction.cs

@@ -70,11 +70,13 @@ namespace ICSharpCode.Decompiler.IL
 			return a;
 		}
 		
-		InstructionFlags flags = (InstructionFlags)(-1);
+		const InstructionFlags invalidFlags = (InstructionFlags)(-1);
+		
+		InstructionFlags flags = invalidFlags;
 		
 		public InstructionFlags Flags {
 			get {
-				if (flags == (InstructionFlags)(-1)) {
+				if (flags == invalidFlags) {
 					flags = ComputeFlags();
 				}
 				return flags;
@@ -89,20 +91,10 @@ namespace ICSharpCode.Decompiler.IL
 			return (this.Flags & flags) != 0;
 		}
 		
-		protected void SetChildInstruction(ref ILInstruction childPointer, ILInstruction newValue)
-		{
-			childPointer = newValue;
-			flags = (InstructionFlags)(-1);
-		}
-		
-		protected internal void AddChildInstruction(ILInstruction newChild)
+		protected void InvalidateFlags()
 		{
-			flags = (InstructionFlags)(-1);
-		}
-		
-		protected internal void RemoveChildInstruction(ILInstruction newChild)
-		{
-			flags = (InstructionFlags)(-1);
+			for (ILInstruction inst = this; inst != null && inst.flags != invalidFlags; inst = inst.parent)
+				inst.flags = invalidFlags;
 		}
 		
 		protected abstract InstructionFlags ComputeFlags();
@@ -130,13 +122,9 @@ namespace ICSharpCode.Decompiler.IL
 		public abstract T AcceptVisitor<T>(ILVisitor<T> visitor);
 		
 		/// <summary>
-		/// Computes an aggregate value over the direct children of this instruction.
+		/// Gets the child nodes of this instruction.
 		/// </summary>
-		/// <param name="initial">The initial value used to initialize the accumulator.</param>
-		/// <param name="visitor">The visitor used to compute the value for the child instructions.</param>
-		/// <param name="func">The function that combines the accumulator with the computed child value.</param>
-		/// <returns>The final value in the accumulator.</returns>
-		public abstract TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func);
+		public abstract IEnumerable<ILInstruction> Children { get; }
 		
 		/// <summary>
 		/// Transforms the children of this instruction by applying the specified visitor.
@@ -151,5 +139,84 @@ namespace ICSharpCode.Decompiler.IL
 		/// <param name="instructionStack">The instruction stack.</param>
 		/// <param name="finished">Receives 'true' if all open 'pop' or 'peek' placeholders were inlined into; false otherwise.</param>
 		internal abstract ILInstruction Inline(InstructionFlags flagsBefore, Stack<ILInstruction> instructionStack, out bool finished);
+		
+		/// <summary>
+		/// Number of parents that refer to this instruction and are connected to the root.
+		/// Usually is 0 for unconnected nodes and 1 for connected nodes, but may temporarily increase to 2
+		/// when the ILAst is re-arranged (e.g. within SetChildInstruction).
+		/// </summary>
+		byte refCount;
+		
+		internal void AddRef()
+		{
+			if (refCount++ == 0) {
+				Connected();
+			}
+		}
+		
+		internal void ReleaseRef()
+		{
+			Debug.Assert(refCount > 0);
+			if (--refCount == 0) {
+				Disconnected();
+			}
+		}
+		
+		protected bool IsConnected {
+			get { return refCount > 0; }
+		}
+		
+		protected virtual void Connected()
+		{
+			foreach (var child in Children)
+				child.AddRef();
+		}
+		
+		protected virtual void Disconnected()
+		{
+			foreach (var child in Children)
+				child.ReleaseRef();
+		}
+		
+		ILInstruction parent;
+		
+		/// <summary>
+		/// Gets the parent of this ILInstruction.
+		/// </summary>
+		public ILInstruction Parent {
+			get { return parent; }
+		}
+		
+		protected void SetChildInstruction(ref ILInstruction childPointer, ILInstruction newValue)
+		{
+			if (childPointer == newValue)
+				return;
+			if (refCount > 0) {
+				// The new value may be a subtree of the old value.
+				// We first call AddRef(), then ReleaseRef() to prevent the subtree
+				// that stays connected from receiving a Disconnected() notification followed by a Connected() notification.
+				newValue.AddRef();
+				childPointer.ReleaseRef();
+			}
+			childPointer = newValue;
+			newValue.parent = this;
+			InvalidateFlags();
+		}
+		
+		protected internal void AddChildInstruction(ILInstruction newChild)
+		{
+			if (refCount > 0)
+				newChild.AddRef();
+			newChild.parent = this;
+			InvalidateFlags();
+		}
+		
+		protected internal void RemoveChildInstruction(ILInstruction newChild)
+		{
+			if (refCount > 0)
+				newChild.ReleaseRef();
+			InvalidateFlags();
+		}
+		
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/Return.cs

@@ -57,12 +57,11 @@ namespace ICSharpCode.Decompiler.IL
 			}
 		}
 		
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			if (returnValue != null)
-				value = func(value, returnValue.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				if (returnValue != null)
+					yield return returnValue;
+			}
 		}
 		
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)

ICSharpCode.Decompiler/IL/Instructions/SimpleInstruction.cs

@@ -21,6 +21,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using ICSharpCode.NRefactory;
 
 namespace ICSharpCode.Decompiler.IL
 {
@@ -38,9 +39,10 @@ namespace ICSharpCode.Decompiler.IL
 			output.Write(OpCode);
 		}
 		
-		public sealed override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			return initial;
+		public sealed override IEnumerable<ILInstruction> Children {
+			get {
+				return EmptyList<ILInstruction>.Instance;
+			}
 		}
 		
 		public sealed override void TransformChildren(ILVisitor<ILInstruction> visitor)

ICSharpCode.Decompiler/IL/Instructions/TryCatch.cs

@@ -68,13 +68,12 @@ namespace ICSharpCode.Decompiler.IL
 			return this;
 		}
 		
-		public override TAccumulate AggregateChildren<TSource, TAccumulate>(TAccumulate initial, ILVisitor<TSource> visitor, Func<TAccumulate, TSource, TAccumulate> func)
-		{
-			TAccumulate value = initial;
-			value = func(value, tryBlock.AcceptVisitor(visitor));
-			foreach (var handler in CatchHandlers)
-				value = func(value, handler.AcceptVisitor(visitor));
-			return value;
+		public override IEnumerable<ILInstruction> Children {
+			get {
+				yield return tryBlock;
+				foreach (var handler in CatchHandlers)
+					yield return handler;
+			}
 		}
 		
 		public override void TransformChildren(ILVisitor<ILInstruction> visitor)

ICSharpCode.Decompiler/IL/Visitors/CountPopInstructionsVisitor.cs

@@ -1,40 +0,0 @@
-// Copyright (c) 2014 Daniel Grunwald
-// 
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-// 
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-using System;
-
-namespace ICSharpCode.Decompiler.IL.Visitors
-{
-	sealed class CountPopInstructionsVisitor : ILVisitor<int>
-	{
-		protected override int Default(ILInstruction inst)
-		{
-			return inst.AggregateChildren(0, this, (a, b) => a + b);
-		}
-		
-		protected internal override int VisitPop(Pop inst)
-		{
-			return 1;
-		}
-		
-		protected internal override int VisitBlock(Block inst)
-		{
-			throw new NotImplementedException();
-		}
-	}
-}