Keep track of original IL ranges

ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs

@@ -117,7 +117,8 @@ namespace Decompiler
 			if (node is ILLabel) {
 				yield return new Ast.LabelStatement { Label = ((ILLabel)node).Name };
 			} else if (node is ILExpression) {
-				object codeExpr = TransformExpression((ILExpression)node);
+				List<ILRange> ilRanges = ((ILExpression)node).GetILRanges();
+				AstNode codeExpr = TransformExpression((ILExpression)node).WithAnnotation(ilRanges);
 				if (codeExpr != null) {
 					if (codeExpr is Ast.Expression) {
 						yield return new Ast.ExpressionStatement { Expression = (Ast.Expression)codeExpr };
@@ -197,7 +198,7 @@ namespace Decompiler
 			return args;
 		}
 		
-		object TransformExpression(ILExpression expr)
+		AstNode TransformExpression(ILExpression expr)
 		{
 			List<Ast.Expression> args = TransformExpressionArguments(expr);
 			return TransformByteCode(methodDef, expr, args);
@@ -260,7 +261,7 @@ namespace Decompiler
 			*/
 		}
 		
-		static object TransformByteCode(MethodDefinition methodDef, ILExpression byteCode, List<Ast.Expression> args)
+		static AstNode TransformByteCode(MethodDefinition methodDef, ILExpression byteCode, List<Ast.Expression> args)
 		{
 			try {
 				AstNode ret = TransformByteCode_Internal(methodDef, byteCode, args);

ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs

@@ -32,6 +32,7 @@ namespace Decompiler
 		{
 			public ILLabel  Label;    // Non-null only if needed
 			public int      Offset;
+			public int      EndOffset;
 			public OpCode   OpCode;
 			public object   Operand;
 			public int?     PopCount; // Null means pop all
@@ -118,6 +119,7 @@ namespace Decompiler
 				MethodBodyRocks.ExpandMacro(ref opCode, ref operand, methodDef.Body);
 				ByteCode byteCode = new ByteCode() {
 					Offset      = inst.Offset,
+					EndOffset   = inst.Next != null ? inst.Next.Offset : methodDef.Body.CodeSize,
 					OpCode      = opCode,
 					Operand     = operand,
 					PopCount    = inst.GetPopCount(),
@@ -360,6 +362,7 @@ namespace Decompiler
 				MethodBodyRocks.ExpandMacro(ref opCode, ref operand, methodDef.Body);
 				
 				ILExpression expr = new ILExpression(opCode, operand);
+				expr.ILRanges.Add(new ILRange() { From = byteCode.Offset, To = byteCode.EndOffset });
 				
 				// Label for this instruction
 				if (byteCode.Label != null) {
@@ -417,6 +420,9 @@ namespace Decompiler
 							bool canInline;
 							allowInline.TryGetValue((ILVariable)arg.Operand, out canInline);
 							if (arg.Operand == currExpr.Operand && canInline) {
+								// Assigne the ranges for optimized away instrustions somewhere
+								currExpr.Arguments[0].ILRanges.AddRange(currExpr.ILRanges);
+								currExpr.Arguments[0].ILRanges.AddRange(nextExpr.Arguments[j].ILRanges);
 								ast.RemoveAt(i);
 								nextExpr.Arguments[j] = currExpr.Arguments[0]; // Inline the stloc body
 								i -= 2; // Try the same index again

ICSharpCode.Decompiler/ILAst/ILAstOptimizer.cs

@@ -55,6 +55,7 @@ namespace Decompiler.ControlFlow
 		void SplitToMovableBlocks(ILBlock block)
 		{
 			// Remve no-ops
+			// TODO: Assign the no-op range to someting
 			block.Body = block.Body.Where(n => !(n is ILExpression && ((ILExpression)n).OpCode == OpCodes.Nop)).ToList();
 			
 			List<ILNode> moveableBlocks = new List<ILNode>();
@@ -417,6 +418,7 @@ namespace Decompiler.ControlFlow
 		
 		void SimpleGotoRemoval(ILBlock ast)
 		{
+			// TODO: Assign IL ranges from br to something else
 			var blocks = ast.GetSelfAndChildrenRecursive<ILBlock>().ToList();
 			foreach(ILBlock block in blocks) {
 				for (int i = 0; i < block.Body.Count; i++) {

ICSharpCode.Decompiler/ILAst/ILAstTypes.cs

@@ -1,11 +1,11 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-using Decompiler.ControlFlow;
-using Mono.Cecil;
-using Mono.Cecil.Cil;
-using Cecil = Mono.Cecil;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Decompiler.ControlFlow;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using Cecil = Mono.Cecil;
 
 namespace Decompiler
 {
@@ -119,17 +119,31 @@ namespace Decompiler
 		}
 	}
 	
+	public class ILRange
+	{
+		public int From;
+		public int To;   // Exlusive
+		
+		public override string ToString()
+		{
+			return string.Format("{0}-{1}", From, To);
+		}
+	}
+	
 	public class ILExpression: ILNode
 	{
 		public OpCode OpCode { get; set; }
 		public object Operand { get; set; }
 		public List<ILExpression> Arguments { get; set; }
+		// Mapping to the original instructions (useful for debugging)
+		public List<ILRange> ILRanges { get; set; }
 		
 		public ILExpression(OpCode opCode, object operand, params ILExpression[] args)
 		{
 			this.OpCode = opCode;
 			this.Operand = operand;
 			this.Arguments = new List<ILExpression>(args);
+			this.ILRanges  = new List<ILRange>(1);
 		}
 		
 		public IEnumerable<ILLabel> GetBranchTargets()
@@ -143,6 +157,27 @@ namespace Decompiler
 			}
 		}
 		
+		public List<ILRange> GetILRanges()
+		{
+			List<ILRange> ranges = new List<ILRange>();
+			foreach(ILExpression expr in this.GetSelfAndChildrenRecursive<ILExpression>()) {
+				ranges.AddRange(expr.ILRanges);
+			}
+			ranges = ranges.OrderBy(r => r.From).ToList();
+			for (int i = 0; i < ranges.Count - 1;) {
+				ILRange curr = ranges[i];
+				ILRange next = ranges[i + 1];
+				// Merge consequtive ranges if they intersect
+				if (curr.From <= next.From && next.From <= curr.To) {
+					curr.To = Math.Max(curr.To, next.To);
+					ranges.RemoveAt(i + 1);
+				} else {
+					i++;
+				}
+			}
+			return ranges;
+		}
+		
 		public override IEnumerable<ILNode> GetChildren()
 		{
 			return Arguments;