diff --git a/ICSharpCode.Decompiler/Ast/AstBuilder.cs b/ICSharpCode.Decompiler/Ast/AstBuilder.cs
index be98d8dcf..58d4ee66c 100644
--- a/ICSharpCode.Decompiler/Ast/AstBuilder.cs
+++ b/ICSharpCode.Decompiler/Ast/AstBuilder.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
@@ -7,6 +8,7 @@ using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Threading;
+
 using ICSharpCode.Decompiler;
 using ICSharpCode.Decompiler.Ast.Transforms;
 using ICSharpCode.Decompiler.ILAst;
@@ -29,7 +31,7 @@ namespace ICSharpCode.Decompiler.Ast
 		IncludeTypeParameterDefinitions = 2
 	}
 	
-	public class AstBuilder
+	public class AstBuilder : ICodeMappings
 	{
 		DecompilerContext context;
 		CompilationUnit astCompileUnit = new CompilationUnit();
@@ -42,6 +44,8 @@ namespace ICSharpCode.Decompiler.Ast
 				throw new ArgumentNullException("context");
 			this.context = context;
 			this.DecompileMethodBodies = true;
+			
+			this.LocalVariables = new ConcurrentDictionary<int, IEnumerable<ILVariable>>();
 		}
 		
 		public static bool MemberIsHidden(MemberReference member, DecompilerSettings settings)
@@ -192,6 +196,11 @@ namespace ICSharpCode.Decompiler.Ast
 		/// <returns>TypeDeclaration or DelegateDeclaration.</returns>
 		public AttributedNode CreateType(TypeDefinition typeDef)
 		{
+			// create CSharp code mappings - used for debugger
+			if (this.CodeMappings == null)
+				this.CodeMappings = new Tuple<string, List<MemberMapping>>(typeDef.FullName, new List<MemberMapping>());
+			
+			// create type
 			TypeDefinition oldCurrentType = context.CurrentType;
 			context.CurrentType = typeDef;
 			TypeDeclaration astType = new TypeDeclaration();
@@ -615,6 +624,9 @@ namespace ICSharpCode.Decompiler.Ast
 
 		AttributedNode CreateMethod(MethodDefinition methodDef)
 		{
+			// Create mapping - used in debugger
+			MemberMapping methodMapping = methodDef.CreateCodeMapping(this.CodeMappings);
+			
 			MethodDeclaration astMethod = new MethodDeclaration();
 			astMethod.AddAnnotation(methodDef);
 			astMethod.ReturnType = ConvertType(methodDef.ReturnType, methodDef.MethodReturnType);
@@ -657,6 +669,7 @@ namespace ICSharpCode.Decompiler.Ast
 					return op;
 				}
 			}
+			astMethod.WithAnnotation(methodMapping);
 			return astMethod;
 		}
 
@@ -700,6 +713,9 @@ namespace ICSharpCode.Decompiler.Ast
 		
 		ConstructorDeclaration CreateConstructor(MethodDefinition methodDef)
 		{
+			// Create mapping - used in debugger
+			MemberMapping methodMapping = methodDef.CreateCodeMapping(this.CodeMappings);
+			
 			ConstructorDeclaration astMethod = new ConstructorDeclaration();
 			astMethod.AddAnnotation(methodDef);
 			astMethod.Modifiers = ConvertModifiers(methodDef);
@@ -711,6 +727,7 @@ namespace ICSharpCode.Decompiler.Ast
 			astMethod.Parameters.AddRange(MakeParameters(methodDef));
 			astMethod.Body = CreateMethodBody(methodDef, astMethod.Parameters);
 			ConvertAttributes(astMethod, methodDef);
+			astMethod.WithAnnotation(methodMapping);
 			return astMethod;
 		}
 
@@ -759,6 +776,9 @@ namespace ICSharpCode.Decompiler.Ast
 			astProp.Name = CleanName(propDef.Name);
 			astProp.ReturnType = ConvertType(propDef.PropertyType, propDef);
 			if (propDef.GetMethod != null) {
+				// Create mapping - used in debugger
+				MemberMapping methodMapping = propDef.GetMethod.CreateCodeMapping(this.CodeMappings);
+				
 				astProp.Getter = new Accessor();
 				astProp.Getter.Body = CreateMethodBody(propDef.GetMethod);
 				astProp.AddAnnotation(propDef.GetMethod);
@@ -766,8 +786,13 @@ namespace ICSharpCode.Decompiler.Ast
 				
 				if ((getterModifiers & Modifiers.VisibilityMask) != (astProp.Modifiers & Modifiers.VisibilityMask))
 					astProp.Getter.Modifiers = getterModifiers & Modifiers.VisibilityMask;
+				
+				astProp.Getter.WithAnnotation(methodMapping);
 			}
 			if (propDef.SetMethod != null) {
+				// Create mapping - used in debugger
+				MemberMapping methodMapping = propDef.SetMethod.CreateCodeMapping(this.CodeMappings);
+				
 				astProp.Setter = new Accessor();
 				astProp.Setter.Body = CreateMethodBody(propDef.SetMethod);
 				astProp.Setter.AddAnnotation(propDef.SetMethod);
@@ -776,6 +801,8 @@ namespace ICSharpCode.Decompiler.Ast
 				
 				if ((setterModifiers & Modifiers.VisibilityMask) != (astProp.Modifiers & Modifiers.VisibilityMask))
 					astProp.Setter.Modifiers = setterModifiers & Modifiers.VisibilityMask;
+				
+				astProp.Setter.WithAnnotation(methodMapping);
 			}
 			ConvertCustomAttributes(astProp, propDef);
 			
@@ -823,16 +850,26 @@ namespace ICSharpCode.Decompiler.Ast
 				else
 					astEvent.PrivateImplementationType = ConvertType(eventDef.AddMethod.Overrides.First().DeclaringType);
 				if (eventDef.AddMethod != null) {
+					// Create mapping - used in debugger
+					MemberMapping methodMapping = eventDef.AddMethod.CreateCodeMapping(this.CodeMappings);
+					
 					astEvent.AddAccessor = new Accessor {
 						Body = CreateMethodBody(eventDef.AddMethod)
 					}.WithAnnotation(eventDef.AddMethod);
 					ConvertAttributes(astEvent.AddAccessor, eventDef.AddMethod);
+					
+					astEvent.AddAccessor.WithAnnotation(methodMapping);
 				}
 				if (eventDef.RemoveMethod != null) {
+					// Create mapping - used in debugger
+					MemberMapping methodMapping = eventDef.RemoveMethod.CreateCodeMapping(this.CodeMappings);
+					
 					astEvent.RemoveAccessor = new Accessor {
 						Body = CreateMethodBody(eventDef.RemoveMethod)
 					}.WithAnnotation(eventDef.RemoveMethod);
 					ConvertAttributes(astEvent.RemoveAccessor, eventDef.RemoveMethod);
+					
+					astEvent.RemoveAccessor.WithAnnotation(methodMapping);
 				}
 				return astEvent;
 			}
@@ -843,7 +880,7 @@ namespace ICSharpCode.Decompiler.Ast
 		BlockStatement CreateMethodBody(MethodDefinition method, IEnumerable<ParameterDeclaration> parameters = null)
 		{
 			if (DecompileMethodBodies)
-				return AstMethodBodyBuilder.CreateMethodBody(method, context, parameters);
+				return AstMethodBodyBuilder.CreateMethodBody(method, context, parameters, LocalVariables);
 			else
 				return null;
 		}
@@ -1315,5 +1352,16 @@ namespace ICSharpCode.Decompiler.Ast
 
 			return type.CustomAttributes.Any(attr => attr.AttributeType.FullName == "System.FlagsAttribute");
 		}
+		
+		/// <summary>
+		/// <inheritdoc/>
+		/// </summary>
+		public Tuple<string, List<MemberMapping>> CodeMappings { get; private set; }
+		
+		/// <summary>
+		/// Gets the local variables for the current decompiled type, method, etc.
+		/// <remarks>The key is the metadata token.</remarks>
+		/// </summary>
+		public ConcurrentDictionary<int, IEnumerable<ILVariable>> LocalVariables { get; private set; }
 	}
 }
diff --git a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
index 368dadefd..888a9e98d 100644
--- a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
+++ b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
@@ -32,9 +32,16 @@ namespace ICSharpCode.Decompiler.Ast
 		/// <param name="context">Decompilation context.</param>
 		/// <param name="parameters">Parameter declarations of the method being decompiled.
 		/// These are used to update the parameter names when the decompiler generates names for the parameters.</param>
+		/// <param name="localVariables">Local variables storage that will be filled/updated with the local variables.</param>
 		/// <returns>Block for the method body</returns>
-		public static BlockStatement CreateMethodBody(MethodDefinition methodDef, DecompilerContext context, IEnumerable<ParameterDeclaration> parameters = null)
+		public static BlockStatement CreateMethodBody(MethodDefinition methodDef,
+		                                              DecompilerContext context,
+		                                              IEnumerable<ParameterDeclaration> parameters = null,
+		                                              ConcurrentDictionary<int, IEnumerable<ILVariable>> localVariables = null)
 		{
+			if (localVariables == null)
+				localVariables = new ConcurrentDictionary<int, IEnumerable<ILVariable>>();
+			
 			MethodDefinition oldCurrentMethod = context.CurrentMethod;
 			Debug.Assert(oldCurrentMethod == null || oldCurrentMethod == methodDef);
 			context.CurrentMethod = methodDef;
@@ -44,10 +51,10 @@ namespace ICSharpCode.Decompiler.Ast
 				builder.context = context;
 				builder.typeSystem = methodDef.Module.TypeSystem;
 				if (Debugger.IsAttached) {
-					return builder.CreateMethodBody(parameters);
+					return builder.CreateMethodBody(parameters, localVariables);
 				} else {
 					try {
-						return builder.CreateMethodBody(parameters);
+						return builder.CreateMethodBody(parameters, localVariables);
 					} catch (OperationCanceledException) {
 						throw;
 					} catch (Exception ex) {
@@ -59,10 +66,14 @@ namespace ICSharpCode.Decompiler.Ast
 			}
 		}
 		
-		public BlockStatement CreateMethodBody(IEnumerable<ParameterDeclaration> parameters)
+		public BlockStatement CreateMethodBody(IEnumerable<ParameterDeclaration> parameters,
+		                                       ConcurrentDictionary<int, IEnumerable<ILVariable>> localVariables)
 		{
 			if (methodDef.Body == null) return null;
 			
+			if (localVariables == null)
+				throw new ArgumentException("localVariables must be instantiated");
+			
 			context.CancellationToken.ThrowIfCancellationRequested();
 			ILBlock ilMethod = new ILBlock();
 			ILAstBuilder astBuilder = new ILAstBuilder();
@@ -102,6 +113,10 @@ namespace ICSharpCode.Decompiler.Ast
 				astBlock.Statements.InsertBefore(insertionPoint, newVarDecl);
 			}
 			
+			// store the variables - used for debugger
+			int token = methodDef.MetadataToken.ToInt32();
+			localVariables.AddOrUpdate(token, allVariables, (key, oldValue) => allVariables);
+			
 			return astBlock;
 		}
 		
@@ -215,10 +230,20 @@ namespace ICSharpCode.Decompiler.Ast
 		{
 			AstNode node = TransformByteCode(expr);
 			Expression astExpr = node as Expression;
+			
+			// get IL ranges - used in debugger
+			List<ILRange> ilRanges = ILRange.OrderAndJoint(expr.GetSelfAndChildrenRecursive<ILExpression>().SelectMany(e => e.ILRanges));
+			AstNode result;
+			
 			if (astExpr != null)
-				return Convert(astExpr, expr.InferredType, expr.ExpectedType);
+				result = Convert(astExpr, expr.InferredType, expr.ExpectedType);
 			else
-				return node;
+				result = node;
+			
+			if (result != null)
+				return result.WithAnnotation(ilRanges);
+			
+			return result;
 		}
 		
 		AstNode TransformByteCode(ILExpression byteCode)
diff --git a/ICSharpCode.Decompiler/Ast/TextOutputFormatter.cs b/ICSharpCode.Decompiler/Ast/TextOutputFormatter.cs
index 101371535..1e6915872 100644
--- a/ICSharpCode.Decompiler/Ast/TextOutputFormatter.cs
+++ b/ICSharpCode.Decompiler/Ast/TextOutputFormatter.cs
@@ -4,7 +4,9 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.ILAst;
 using ICSharpCode.NRefactory.CSharp;
 using Mono.Cecil;
 
@@ -121,6 +123,28 @@ namespace ICSharpCode.Decompiler.Ast
 		
 		public void StartNode(AstNode node)
 		{
+			var ranges = node.Annotation<List<ILRange>>();
+			if (ranges != null && ranges.Count > 0)
+			{
+				// find the ancestor that has method mapping as annotation
+				if (node.Ancestors != null && node.Ancestors.Count() > 0)
+				{
+					var n = node.Ancestors.FirstOrDefault(a => a.Annotation<MemberMapping>() != null);
+					if (n != null) {
+						MemberMapping mapping = n.Annotation<MemberMapping>();
+
+						// add all ranges
+						foreach (var range in ranges) {
+							mapping.MemberCodeMappings.Add(new SourceCodeMapping {
+							                               	ILInstructionOffset = range,
+							                               	SourceCodeLine = output.CurrentLine,
+							                               	MemberMapping = mapping
+							                               });
+						}
+					}
+				}
+			}
+			
 			nodeStack.Push(node);
 		}
 		
diff --git a/ICSharpCode.Decompiler/CodeMappings.cs b/ICSharpCode.Decompiler/CodeMappings.cs
new file mode 100644
index 000000000..c169d0e6f
--- /dev/null
+++ b/ICSharpCode.Decompiler/CodeMappings.cs
@@ -0,0 +1,307 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under MIT X11 license (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+
+using ICSharpCode.Decompiler.Ast;
+using ICSharpCode.Decompiler.Disassembler;
+using ICSharpCode.Decompiler.ILAst;
+using Mono.Cecil;
+
+namespace ICSharpCode.Decompiler
+{
+	public enum DecompiledLanguages
+	{
+		IL,
+		CSharp
+	}
+	
+	/// <summary>
+	/// Interface for decompliler classes : AstBuilder & ReflectionDisassembler.
+	/// </summary>
+	public interface ICodeMappings
+	{
+		/// <summary>
+		/// Gets the code mappings.
+		/// </summary>
+		Tuple<string, List<MemberMapping>> CodeMappings { get; }
+	}
+	
+	/// <summary>
+	/// Maps the source code to IL.
+	/// </summary>
+	public sealed class SourceCodeMapping
+	{
+		/// <summary>
+		/// Gets or sets the source code line number in the output.
+		/// </summary>
+		public int SourceCodeLine { get; internal set; }
+		
+		/// <summary>
+		/// Gets or sets IL Range offset for the source code line. E.g.: 13-19 &lt;-&gt; 135.
+		/// </summary>
+		public ILRange ILInstructionOffset { get; internal set; }
+		
+		/// <summary>
+		/// Gets or sets the member mapping this source code mapping belongs to.
+		/// </summary>
+		public MemberMapping MemberMapping { get; internal set; }
+		
+		/// <summary>
+		/// Retrieves the array that contains the IL range and the missing gaps between ranges.
+		/// </summary>
+		/// <returns>The array representation of the step aranges.</returns>
+		public int[] ToArray(bool isMatch)
+		{
+			var currentList = new List<ILRange>();
+			
+			// add list for the current source code line
+			currentList.AddRange(ILRange.OrderAndJoint(MemberMapping.MemberCodeMappings
+			                                           .FindAll(m => m.SourceCodeLine == this.SourceCodeLine)
+			                                           .ConvertAll<ILRange>(m => m.ILInstructionOffset)));
+			
+			if (!isMatch) {
+				// add inverted
+				currentList.AddRange(MemberMapping.InvertedList);
+			} else {
+				// if the current list contains the last mapping, add also the last gap
+				var lastInverted = MemberMapping.InvertedList.LastOrDefault();
+				if (lastInverted != null && lastInverted.From == currentList[currentList.Count - 1].To)
+					currentList.Add(lastInverted);
+			}
+			
+			// set the output
+			var resultList = new List<int>();
+			foreach (var element in ILRange.OrderAndJoint(currentList)) {
+				resultList.Add(element.From);
+				resultList.Add(element.To);
+			}
+			
+			return resultList.ToArray();
+		}
+	}
+	
+	/// <summary>
+	/// Stores the method information and its source code mappings.
+	/// </summary>
+	public sealed class MemberMapping
+	{
+		IEnumerable<ILRange> invertedList;
+		
+		/// <summary>
+		/// Gets or sets the type of the mapping.
+		/// </summary>
+		public MemberReference MemberReference { get; internal set; }
+		
+		/// <summary>
+		/// Metadata token of the method.
+		/// </summary>
+		public uint MetadataToken { get; internal set; }
+		
+		/// <summary>
+		/// Gets or sets the code size for the member mapping.
+		/// </summary>
+		public int CodeSize { get; internal set; }
+		
+		/// <summary>
+		/// Gets or sets the source code mappings.
+		/// </summary>
+		public List<SourceCodeMapping> MemberCodeMappings { get; internal set; }
+		
+		/// <summary>
+		/// Gets the inverted IL Ranges.<br/>
+		/// E.g.: for (0-9, 11-14, 14-18, 21-25) => (9-11,18-21).
+		/// </summary>
+		/// <returns>IL Range inverted list.</returns>
+		public IEnumerable<ILRange> InvertedList
+		{
+			get {
+				if (invertedList == null) {
+					var list = MemberCodeMappings.ConvertAll<ILRange>(
+						s => new ILRange { From = s.ILInstructionOffset.From, To = s.ILInstructionOffset.To });
+					invertedList = ILRange.OrderAndJoint(ILRange.Invert(list, CodeSize));
+				}
+				return invertedList;
+			}
+		}
+	}
+	
+	/// <summary>
+	/// Code mappings helper class.
+	/// </summary>
+	public static class CodeMappings
+	{	
+		/// <summary>
+		/// Create code mapping for a method.
+		/// </summary>
+		/// <param name="method">Method to create the mapping for.</param>
+		/// <param name="sourceCodeMappings">Source code mapping storage.</param>
+		internal static MemberMapping CreateCodeMapping(
+			this MethodDefinition member,
+			Tuple<string, List<MemberMapping>> codeMappings)
+		{
+			if (member == null || !member.HasBody)
+				return null;
+			
+			if (codeMappings == null)
+				return null;
+			
+			// create IL/CSharp code mappings - used in debugger
+			MemberMapping currentMemberMapping = null;
+			if (codeMappings.Item1 == member.DeclaringType.FullName) {
+				var mapping = codeMappings.Item2;
+				if (mapping.Find(map => (int)map.MetadataToken == member.MetadataToken.ToInt32()) == null) {
+					currentMemberMapping = new MemberMapping() {
+						MetadataToken = (uint)member.MetadataToken.ToInt32(),
+						MemberReference = member.DeclaringType.Resolve(),
+						MemberCodeMappings = new List<SourceCodeMapping>(),
+						CodeSize = member.Body.CodeSize
+					};
+					mapping.Add(currentMemberMapping);
+				}
+			}
+			
+			return currentMemberMapping;
+		}
+		
+		/// <summary>
+		/// Gets source code mapping and metadata token based on type name and line number.
+		/// </summary>
+		/// <param name="codeMappings">Code mappings storage.</param>
+		/// <param name="typeName">Type name.</param>
+		/// <param name="lineNumber">Line number.</param>
+		/// <param name="metadataToken">Metadata token.</param>
+		/// <returns></returns>
+		public static SourceCodeMapping GetInstructionByTypeAndLine(
+			this Tuple<string, List<MemberMapping>> codeMappings,
+			string memberReferenceName,
+			int lineNumber,
+			out uint metadataToken)
+		{
+			if (codeMappings == null)
+				throw new ArgumentNullException("CodeMappings storage must be valid!");
+			
+			if (codeMappings.Item1 != memberReferenceName) {
+				metadataToken = 0;
+				return null;
+			}
+			
+			if (lineNumber <= 0) {
+				metadataToken = 0;
+				return null;
+			}
+			
+			var methodMappings = codeMappings.Item2;
+			foreach (var maping in methodMappings) {
+				var map = maping.MemberCodeMappings.Find(m => m.SourceCodeLine == lineNumber);
+				if (map != null) {
+					metadataToken = maping.MetadataToken;
+					return map;
+				}
+			}
+			
+			metadataToken = 0;
+			return null;
+		}
+		
+		/// <summary>
+		/// Gets a mapping given a type, a token and an IL offset.
+		/// </summary>
+		/// <param name="codeMappings">Code mappings storage.</param>
+		/// <param name="typeName">Type name.</param>
+		/// <param name="token">Token.</param>
+		/// <param name="ilOffset">IL offset.</param>
+		/// <param name="isMatch">True, if perfect match.</param>
+		/// <returns>A code mapping.</returns>
+		public static SourceCodeMapping GetInstructionByTypeTokenAndOffset(
+			this Tuple<string, List<MemberMapping>> codeMappings,
+			string memberReferenceName,
+			uint token,
+			int ilOffset, out bool isMatch)
+		{
+			isMatch = false;
+			memberReferenceName = memberReferenceName.Replace("+", "/");
+			
+			if (codeMappings == null)
+				throw new ArgumentNullException("CodeMappings storage must be valid!");
+			
+			if (codeMappings.Item1 != memberReferenceName) {
+				return null;
+			}
+			
+			var methodMappings = codeMappings.Item2;
+			var maping = methodMappings.Find(m => m.MetadataToken == token);
+			
+			if (maping == null) {
+				return null;
+			}
+			
+			// try find an exact match
+			var map = maping.MemberCodeMappings.Find(m => m.ILInstructionOffset.From <= ilOffset && ilOffset < m.ILInstructionOffset.To);
+			
+			if (map == null) {
+				// get the immediate next one
+				map = maping.MemberCodeMappings.Find(m => m.ILInstructionOffset.From >= ilOffset);
+				isMatch = false;
+				if (map == null)
+					map = maping.MemberCodeMappings.LastOrDefault(); // get the last
+				
+				return map;
+			}
+			
+			isMatch = true;
+			return map;
+		}
+		
+		/// <summary>
+		/// Gets the source code and type name from metadata token and offset.
+		/// </summary>
+		/// <param name="codeMappings">Code mappings storage.</param>
+		/// <param name="typeName">Current type name.</param>
+		/// <param name="token">Metadata token.</param>
+		/// <param name="ilOffset">IL offset.</param>
+		/// <param name="typeName">Type definition.</param>
+		/// <param name="line">Line number.</param>
+		/// <remarks>It is possible to exist to different types from different assemblies with the same metadata token.</remarks>
+		public static bool GetSourceCodeFromMetadataTokenAndOffset(
+			this Tuple<string, List<MemberMapping>> codeMappings,
+			string memberReferenceName,
+			uint token,
+			int ilOffset,
+			out MemberReference type,
+			out int line)
+		{
+			type = null;
+			line = 0;
+			
+			if (codeMappings == null)
+				throw new ArgumentNullException("CodeMappings storage must be valid!");
+			
+			memberReferenceName = memberReferenceName.Replace("+", "/");
+			if (codeMappings.Item1 != memberReferenceName)
+				return false;
+			
+			var mapping = codeMappings.Item2.Find(m => m.MetadataToken == token);
+			if (mapping == null)
+				return false;
+			
+			var codeMapping = mapping.MemberCodeMappings.Find(
+				cm => cm.ILInstructionOffset.From <= ilOffset && ilOffset <= cm.ILInstructionOffset.To - 1);
+			if (codeMapping == null) {
+				codeMapping = mapping.MemberCodeMappings.Find(cm => (cm.ILInstructionOffset.From >= ilOffset));
+				if (codeMapping == null) {
+					codeMapping = mapping.MemberCodeMappings.LastOrDefault();
+					if (codeMapping == null)
+						return false;
+				}
+			}
+			
+			type = mapping.MemberReference;
+			line = codeMapping.SourceCodeLine;
+			return true;
+		}
+	}
+}
diff --git a/ICSharpCode.Decompiler/Disassembler/MethodBodyDisassembler.cs b/ICSharpCode.Decompiler/Disassembler/MethodBodyDisassembler.cs
index 32161a3f8..ef2f8a980 100644
--- a/ICSharpCode.Decompiler/Disassembler/MethodBodyDisassembler.cs
+++ b/ICSharpCode.Decompiler/Disassembler/MethodBodyDisassembler.cs
@@ -20,8 +20,10 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
+
 using ICSharpCode.Decompiler;
 using ICSharpCode.Decompiler.FlowAnalysis;
+using ICSharpCode.Decompiler.ILAst;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 
@@ -45,8 +47,9 @@ namespace ICSharpCode.Decompiler.Disassembler
 			this.cancellationToken = cancellationToken;
 		}
 		
-		public void Disassemble(MethodBody body)
+		public void Disassemble(MethodBody body, MemberMapping methodMapping)
 		{
+			// start writing IL code
 			MethodDefinition method = body.Method;
 			output.WriteLine("// Method begins at RVA 0x{0:x4}", method.RVA);
 			if (method.HasOverrides)
@@ -77,10 +80,19 @@ namespace ICSharpCode.Decompiler.Disassembler
 			
 			if (detectControlStructure && body.Instructions.Count > 0) {
 				Instruction inst = body.Instructions[0];
-				WriteStructureBody(new ILStructure(body), ref inst);
+				WriteStructureBody(new ILStructure(body), ref inst, methodMapping, method.Body.CodeSize);
 			} else {
 				foreach (var inst in method.Body.Instructions) {
 					inst.WriteTo(output);
+					
+					// add IL code mappings - used in debugger
+					methodMapping.MemberCodeMappings.Add(
+						new SourceCodeMapping() {
+							SourceCodeLine = output.CurrentLine,
+							ILInstructionOffset = new ILRange { From = inst.Offset, To = inst.Next == null ? method.Body.CodeSize : inst.Next.Offset },
+							MemberMapping = methodMapping
+						});
+					
 					output.WriteLine();
 				}
 				output.WriteLine();
@@ -136,7 +148,7 @@ namespace ICSharpCode.Decompiler.Disassembler
 			output.Indent();
 		}
 		
-		void WriteStructureBody(ILStructure s, ref Instruction inst)
+		void WriteStructureBody(ILStructure s, ref Instruction inst, MemberMapping currentMethodMapping, int codeSize)
 		{
 			int childIndex = 0;
 			while (inst != null && inst.Offset < s.EndOffset) {
@@ -144,10 +156,21 @@ namespace ICSharpCode.Decompiler.Disassembler
 				if (childIndex < s.Children.Count && s.Children[childIndex].StartOffset <= offset && offset < s.Children[childIndex].EndOffset) {
 					ILStructure child = s.Children[childIndex++];
 					WriteStructureHeader(child);
-					WriteStructureBody(child, ref inst);
+					WriteStructureBody(child, ref inst, currentMethodMapping, codeSize);
 					WriteStructureFooter(child);
 				} else {
 					inst.WriteTo(output);
+					
+					// add IL code mappings - used in debugger
+					if (currentMethodMapping != null) {
+						currentMethodMapping.MemberCodeMappings.Add(
+							new SourceCodeMapping() {
+								SourceCodeLine = output.CurrentLine,
+								ILInstructionOffset = new ILRange { From = inst.Offset, To = inst.Next == null ? codeSize : inst.Next.Offset },
+								MemberMapping = currentMethodMapping
+							});
+					}
+					
 					output.WriteLine();
 					inst = inst.Next;
 				}
diff --git a/ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs b/ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs
index db4699562..3ae34ffb3 100644
--- a/ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs
+++ b/ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs
@@ -28,7 +28,7 @@ namespace ICSharpCode.Decompiler.Disassembler
 	/// <summary>
 	/// Disassembles type and member definitions.
 	/// </summary>
-	public sealed class ReflectionDisassembler
+	public sealed class ReflectionDisassembler : ICodeMappings
 	{
 		ITextOutput output;
 		CancellationToken cancellationToken;
@@ -146,8 +146,11 @@ namespace ICSharpCode.Decompiler.Disassembler
 				OpenBlock(defaultCollapsed: isInType);
 				WriteAttributes(method.CustomAttributes);
 				
-				if (method.HasBody)
-					methodBodyDisassembler.Disassemble(method.Body);
+				if (method.HasBody) {
+					// create IL code mappings - used in debugger
+					MemberMapping methodMapping = method.CreateCodeMapping(this.CodeMappings);
+					methodBodyDisassembler.Disassemble(method.Body, methodMapping);
+				}
 				
 				CloseBlock("End of method " + method.DeclaringType.Name + "." + method.Name);
 			} else {
@@ -312,6 +315,11 @@ namespace ICSharpCode.Decompiler.Disassembler
 		
 		public void DisassembleType(TypeDefinition type)
 		{
+			// create IL code mappings - used for debugger
+			if (this.CodeMappings == null)
+				this.CodeMappings = new Tuple<string, List<MemberMapping>>(type.FullName, new List<MemberMapping>());
+			
+			// start writing IL
 			output.WriteDefinition(".class ", type);
 			
 			if ((type.Attributes & TypeAttributes.ClassSemanticMask) == TypeAttributes.Interface)
@@ -558,5 +566,11 @@ namespace ICSharpCode.Decompiler.Disassembler
 			WriteAttributes(asm.CustomAttributes);
 			CloseBlock();
 		}
+		
+		/// <inheritdoc/>
+		public Tuple<string, List<MemberMapping>> CodeMappings {
+			get;
+			private set;
+		}
 	}
 }
diff --git a/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj b/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
index 6e8d0eae8..ee48b4734 100644
--- a/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
+++ b/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
@@ -73,6 +73,7 @@
     <Compile Include="Ast\Transforms\PatternStatementTransform.cs" />
     <Compile Include="Ast\TypesHierarchyHelpers.cs" />
     <Compile Include="CecilExtensions.cs" />
+    <Compile Include="CodeMappings.cs" />
     <Compile Include="DecompilerException.cs" />
     <Compile Include="DecompilerSettings.cs" />
     <Compile Include="Disassembler\DisassemblerHelpers.cs" />
diff --git a/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs b/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs
index f9394fbce..233928531 100644
--- a/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs
+++ b/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs
@@ -1,7 +1,9 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 using Cecil = Mono.Cecil;
diff --git a/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs b/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
index 721458348..7979e5f15 100644
--- a/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
+++ b/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
@@ -210,7 +210,10 @@ namespace ICSharpCode.Decompiler.ILAst
 		
 		public static List<ILRange> OrderAndJoint(IEnumerable<ILRange> input)
 		{
-			List<ILRange> ranges = input.OrderBy(r => r.From).ToList();
+			if (input == null)
+				throw new ArgumentNullException("Input is null!");
+						
+			List<ILRange> ranges = input.Where(r => r != null).OrderBy(r => r.From).ToList();
 			for (int i = 0; i < ranges.Count - 1;) {
 				ILRange curr = ranges[i];
 				ILRange next = ranges[i + 1];
@@ -227,6 +230,12 @@ namespace ICSharpCode.Decompiler.ILAst
 		
 		public static IEnumerable<ILRange> Invert(IEnumerable<ILRange> input, int codeSize)
 		{
+			if (input == null)
+				throw new ArgumentNullException("Input is null!");
+			
+			if (codeSize <= 0)
+				throw new ArgumentException("Code size must be grater than 0");
+			
 			var ordered = OrderAndJoint(input);
 			if (ordered.Count == 0) {
 				yield return new ILRange() { From = 0, To = codeSize };
diff --git a/ICSharpCode.Decompiler/ITextOutput.cs b/ICSharpCode.Decompiler/ITextOutput.cs
index b4374d50b..1cced95f2 100644
--- a/ICSharpCode.Decompiler/ITextOutput.cs
+++ b/ICSharpCode.Decompiler/ITextOutput.cs
@@ -23,6 +23,8 @@ namespace ICSharpCode.Decompiler
 {
 	public interface ITextOutput
 	{
+		int CurrentLine { get; }
+		
 		void Indent();
 		void Unindent();
 		void Write(char ch);
diff --git a/ICSharpCode.Decompiler/PlainTextOutput.cs b/ICSharpCode.Decompiler/PlainTextOutput.cs
index 76721e666..3e167b01b 100644
--- a/ICSharpCode.Decompiler/PlainTextOutput.cs
+++ b/ICSharpCode.Decompiler/PlainTextOutput.cs
@@ -32,13 +32,17 @@ namespace ICSharpCode.Decompiler
 			if (writer == null)
 				throw new ArgumentNullException("writer");
 			this.writer = writer;
+			CurrentLine = 1;
 		}
 		
 		public PlainTextOutput()
 		{
 			this.writer = new StringWriter();
+			CurrentLine = 1;
 		}
 		
+		public int CurrentLine { get; set; }
+		
 		public override string ToString()
 		{
 			return writer.ToString();
@@ -80,6 +84,7 @@ namespace ICSharpCode.Decompiler
 		{
 			writer.WriteLine();
 			needsIndent = true;
+			++CurrentLine;
 		}
 		
 		public void WriteDefinition(string text, object definition)
diff --git a/ILSpy/TextView/AvalonEditTextOutput.cs b/ILSpy/TextView/AvalonEditTextOutput.cs
index 0bcdb7bd5..30d03e967 100644
--- a/ILSpy/TextView/AvalonEditTextOutput.cs
+++ b/ILSpy/TextView/AvalonEditTextOutput.cs
@@ -64,6 +64,8 @@ namespace ICSharpCode.ILSpy.TextView
 	/// </summary>
 	public sealed class AvalonEditTextOutput : ISmartTextOutput
 	{
+		int lineNumber = 1;
+		int lastLineStart = 0;
 		readonly StringBuilder b = new StringBuilder();
 		
 		/// <summary>Current indentation level</summary>
@@ -173,6 +175,8 @@ namespace ICSharpCode.ILSpy.TextView
 			Debug.Assert(textDocument == null);
 			b.AppendLine();
 			needsIndent = true;
+			lastLineStart = b.Length;
+			lineNumber++;
 			if (this.TextLength > LengthLimit) {
 				throw new OutputLengthExceededException();
 			}
@@ -220,5 +224,17 @@ namespace ICSharpCode.ILSpy.TextView
 				this.UIElements.Add(new KeyValuePair<int, Lazy<UIElement>>(this.TextLength, new Lazy<UIElement>(element)));
 			}
 		}
+		
+		public int CurrentLine {
+			get {
+				return lineNumber;
+			}
+		}
+		
+		public int CurrentColumn {
+			get {
+				return b.Length - lastLineStart + 1;
+			}
+		}
 	}
 }