ILAst: show unused IL ranges

ICSharpCode.Decompiler/CSharp/SequencePointBuilder.cs

@@ -171,9 +171,11 @@ namespace ICSharpCode.Decompiler.CSharp
 				return;
 			}
 			// Add the IL range associated with this instruction to the current sequence point.
-			if (!inst.ILRange.IsEmpty && current.Intervals != null) {
+			if (HasUsableILRange(inst) && current.Intervals != null) {
 				current.Intervals.Add(inst.ILRange);
-				current.Function = inst.Parent.Ancestors.OfType<ILFunction>().FirstOrDefault();
+				var function = inst.Parent.Ancestors.OfType<ILFunction>().FirstOrDefault();
+				Debug.Assert(current.Function == null || current.Function == function);
+				current.Function = function;
 			}
 
 			// Do not add instructions of lambdas/delegates.
@@ -187,6 +189,13 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
+		internal static bool HasUsableILRange(ILInstruction inst)
+		{
+			if (inst.ILRange.IsEmpty)
+				return false;
+			return !(inst is BlockContainer || inst is Block);
+		}
+
 		/// <summary>
 		/// Called after the visitor is done to return the results.
 		/// </summary>
@@ -227,6 +236,13 @@ namespace ICSharpCode.Decompiler.CSharp
 					newList.Add(sequencePoint);
 					pos = sequencePoint.EndOffset;
 				}
+				if (pos < function.CecilMethod.Body.CodeSize) {
+					var hidden = new SequencePoint();
+					hidden.Offset = pos;
+					hidden.EndOffset = function.CecilMethod.Body.CodeSize;
+					hidden.SetHidden();
+					newList.Add(hidden);
+				}
 				dict[function] = newList;
 			}
 			return dict;

ICSharpCode.Decompiler/IL/ILAstWritingOptions.cs

@@ -1,8 +1,23 @@
-using System;
-using System.Collections.Generic;
+// Copyright (c) 2017 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.ComponentModel;
 using System.Runtime.CompilerServices;
-using System.Text;
 
 namespace ICSharpCode.Decompiler.IL
 {

ICSharpCode.Decompiler/IL/Instructions/Block.cs

@@ -129,6 +129,7 @@ namespace ICSharpCode.Decompiler.IL
 
 		public override void WriteTo(ITextOutput output, ILAstWritingOptions options)
 		{
+			ILRange.WriteTo(output, options);
 			output.Write("Block ");
 			output.WriteDefinition(Label, this);
 			if (Parent is BlockContainer)

ICSharpCode.Decompiler/IL/Instructions/BlockContainer.cs

@@ -107,6 +107,7 @@ namespace ICSharpCode.Decompiler.IL
 		
 		public override void WriteTo(ITextOutput output, ILAstWritingOptions options)
 		{
+			ILRange.WriteTo(output, options);
 			output.WriteDefinition("BlockContainer", this);
 			output.Write(' ');
 			output.MarkFoldStart("{...}");

ICSharpCode.Decompiler/IL/Instructions/ILFunction.cs

@@ -114,12 +114,41 @@ namespace ICSharpCode.Decompiler.IL
 			}
 
 			body.WriteTo(output, options);
-			
 			output.WriteLine();
+
+			if (options.ShowILRanges) {
+				var unusedILRanges = FindUnusedILRanges();
+				if (!unusedILRanges.IsEmpty) {
+					output.Write("// Unused IL Ranges: ");
+					output.Write(string.Join(", ", unusedILRanges.Intervals.Select(
+						range => $"[{range.Start:x4}..{range.InclusiveEnd:x4}]")));
+					output.WriteLine();
+				}
+			}
+
 			output.Unindent();
 			output.WriteLine("}");
 		}
 		
+		LongSet FindUnusedILRanges()
+		{
+			var usedILRanges = new List<LongInterval>();
+			MarkUsedILRanges(body);
+			return new LongSet(new LongInterval(0, CecilMethod.Body.CodeSize)).ExceptWith(new LongSet(usedILRanges));
+
+			void MarkUsedILRanges(ILInstruction inst)
+			{
+				if (CSharp.SequencePointBuilder.HasUsableILRange(inst)) {
+					usedILRanges.Add(new LongInterval(inst.ILRange.Start, inst.ILRange.End));
+				}
+				if (!(inst is ILFunction)) {
+					foreach (var child in inst.Children) {
+						MarkUsedILRanges(child);
+					}
+				}
+			}
+		}
+
 		protected override InstructionFlags ComputeFlags()
 		{
 			// Creating a lambda may throw OutOfMemoryException