Convert ByteCodeCollection to new data representation: StackExpressionCollection;

Modify the generating code to use this data representation

Decompiler.csproj

@@ -48,6 +48,8 @@
     <Compile Include="src\MainForm.Designer.cs" />
     <Compile Include="src\Program.cs" />
     <Compile Include="src\ByteCode.StackAnalysis.cs" />
+    <Compile Include="src\StackExpression.cs" />
+    <Compile Include="src\StackExpressionCollection.cs" />
     <Compile Include="src\Util.cs" />
     <EmbeddedResource Include="src\MainForm.resx">
       <DependentUpon>MainForm.cs</DependentUpon>

src/AstMetodBodyBuilder.cs

@@ -19,6 +19,7 @@ namespace Decompiler
 			methodDef.Body.Simplify();
 			
 			ByteCodeCollection body = new ByteCodeCollection(methodDef);
+			StackExpressionCollection exprCol = new StackExpressionCollection(body);
 			
 			foreach(VariableDefinition varDef in methodDef.Body.Variables) {
 				Ast.VariableDeclaration astVar = new Ast.VariableDeclaration(varDef.Name);
@@ -27,34 +28,19 @@ namespace Decompiler
 				astBlock.Children.Add(astLocalVar);
 			}
 			
-			foreach(ByteCode byteCode in body) {
+			foreach(StackExpression expr in exprCol) {
-				OpCode opCode = byteCode.OpCode;
-				string description = 
-					string.Format(" {1, -22} # {2}->{3} {4} {5}",
-					              byteCode.Offset,
-					              opCode + " " + FormatByteCodeOperand(byteCode.Operand),
-					              opCode.StackBehaviourPop,
-					              opCode.StackBehaviourPush,
-					              opCode.FlowControl == FlowControl.Next ? string.Empty : "Flow=" + opCode.FlowControl,
-					              opCode.OpCodeType == OpCodeType.Macro ? "(macro)" : string.Empty);
-				
 				Ast.Statement astStatement = null;
 				try {
-					int argCount = byteCode.PopCount;
+					List<Ast.Expression> args = new List<Ast.Expression>();
-					Ast.Expression[] args = new Ast.Expression[argCount];
+					foreach(CilStackSlot stackSlot in expr.StackBefore.PeekCount(expr.PopCount)) {
-					for(int i = 0; i < argCount; i++) {
+						string name = string.Format("expr{0:X2}", stackSlot.AllocadedBy.Offset);
-						ByteCode allocBy = byteCode.StackBefore.Peek(argCount - i).AllocadedBy;
+						args.Add(new Ast.IdentifierExpression(name));
-						string name = string.Format("expr{0:X2}", allocBy.Offset);
-						args[i] = new Ast.IdentifierExpression(name);
 					}
-					object codeExpr = MakeCodeDomExpression(
+					object codeExpr = MakeCodeDomExpression(methodDef, expr, args.ToArray());
-						methodDef,
-						byteCode,
-						args);
 					if (codeExpr is Ast.Expression) {
-						if (byteCode.PushCount == 1) {
+						if (expr.PushCount == 1) {
-							string type = byteCode.Type.FullName;
+							string type = expr.ExpressionByteCode.Type.FullName;
-							string name = string.Format("expr{0:X2}", byteCode.Offset);
+							string name = string.Format("expr{0:X2}", expr.ExpressionByteCode.Offset);
 							Ast.LocalVariableDeclaration astLocal = new Ast.LocalVariableDeclaration(new Ast.TypeReference(type.ToString()));
 							astLocal.Variables.Add(new Ast.VariableDeclaration(name, (Ast.Expression)codeExpr));
 							astStatement = astLocal;
@@ -65,14 +51,12 @@ namespace Decompiler
 						astStatement = (Ast.Statement)codeExpr;
 					}
 				} catch (NotImplementedException) {
-					astStatement = MakeComment(description);
+					astStatement = MakeComment(expr.ExpressionByteCode.Description);
 				}
-				//astBlock.Children.Add(MakeComment(description));
+				if (expr.FirstByteCode.BranchesHere.Count > 0) {
-				if (byteCode.BranchesHere.Count > 0) {
+					astBlock.Children.Add(new Ast.LabelStatement(string.Format("IL_{0:X2}", expr.FirstByteCode.Offset)));
-					astBlock.Children.Add(new Ast.LabelStatement(string.Format("IL_{0:X2}", byteCode.Offset)));
 				}
 				astBlock.Children.Add(astStatement);
-				//astBlock.Children.Add(MakeComment(" " + stackAnalysis.StackAfter[instr].ToString()));
 			}
 			
 			return astBlock;
@@ -84,27 +68,16 @@ namespace Decompiler
 			return new Ast.ExpressionStatement(new PrimitiveExpression(text, text));
 		}
 		
-		static object FormatByteCodeOperand(object operand)
+		static object MakeCodeDomExpression(MethodDefinition methodDef, StackExpression expr, params Ast.Expression[] args)
 		{
-			if (operand == null) {
+			List<Ast.Expression> allArgs = new List<Ast.Expression>();
-				return string.Empty;
+			// Add args from stack
-			} else if (operand is ByteCode) {
+			allArgs.AddRange(args);
-				return string.Format("IL_{0:X2}", ((ByteCode)operand).Offset);
+			// Args generated by nested expressions
-			} else if (operand is MethodReference) {
+			foreach(StackExpression nestedExpr in expr.LastArguments) {
-				return ((MethodReference)operand).Name + "()";
+				allArgs.Add(new Ast.ParenthesizedExpression((Ast.Expression)MakeCodeDomExpression(methodDef, nestedExpr)));
-			} else if (operand is Cecil.TypeReference) {
-				return ((Cecil.TypeReference)operand).FullName;
-			} else if (operand is VariableDefinition) {
-				return ((VariableDefinition)operand).Name;
-			} else if (operand is ParameterDefinition) {
-				return ((ParameterDefinition)operand).Name;
-			} else if (operand is string) {
-				return "\"" + operand + "\"";
-			} else if (operand is int) {
-				return operand.ToString();
-			} else {
-				return "(" + operand.GetType() + ")";
 			}
+			return MakeCodeDomExpression(methodDef, expr.ExpressionByteCode, args);
 		}
 		
 		static object MakeCodeDomExpression(MethodDefinition methodDef, ByteCode byteCode, params Ast.Expression[] args)

src/ByteCode.StackBehaviour.cs

@@ -11,43 +11,19 @@ namespace Decompiler
 	{
 		public int PopCount {
 			get {
-				int popCount;
+				return GetPopCount();
-				int pushCount;
-				SimulateStackSize(out popCount, out pushCount);
-				return popCount;
 			}
 		}
 		
 		public int PushCount {
 			get {
-				int popCount;
+				return GetPushCount();
-				int pushCount;
-				SimulateStackSize(out popCount, out pushCount);
-				return pushCount;
 			}
 		}
 		
-		void SimulateStackSize(out int popCount, out int pushCount)
+		int GetPopCount()
 		{
-			int stackSize = 0;
+			switch(this.OpCode.StackBehaviourPop) {
-			int minStackSize = 0;
-			foreach(ByteCode bc in nestedByteCodes) {
-				stackSize -= bc.PopCount;
-				minStackSize = Math.Min(minStackSize, stackSize);
-				stackSize += bc.PushCount;
-			}
-			{
-				stackSize -= GetPopCount(methodDef, this);
-				minStackSize = Math.Min(minStackSize, stackSize);
-				stackSize += GetPushCount(methodDef, this);
-			}
-			popCount = -minStackSize;
-			pushCount = stackSize - minStackSize;
-		}
-		
-		static int GetPopCount(MethodDefinition methodDef, ByteCode byteCode)
-		{
-			switch(byteCode.OpCode.StackBehaviourPop) {
 				case StackBehaviour.Pop0:   return 0;
 				case StackBehaviour.Pop1:   return 1;
 				case StackBehaviour.Popi:   return 1;
@@ -68,9 +44,9 @@ namespace Decompiler
 				case StackBehaviour.Popref_popi_popref: return 3;
 				case StackBehaviour.PopAll: throw new Exception("PopAll");
 				case StackBehaviour.Varpop: 
-					switch(byteCode.OpCode.Code) {
+					switch(this.OpCode.Code) {
 						case Code.Call:     
-							Cecil.MethodReference cecilMethod = ((MethodReference)byteCode.Operand);
+							Cecil.MethodReference cecilMethod = ((MethodReference)this.Operand);
 							if (cecilMethod.HasThis) {
 								return cecilMethod.Parameters.Count + 1 /* this */;
 							} else {
@@ -87,13 +63,13 @@ namespace Decompiler
 						case Code.Newobj:   throw new NotImplementedException();
 						default: throw new Exception("Unknown Varpop opcode");
 					}
-				default: throw new Exception("Unknown pop behaviour: " + byteCode.OpCode.StackBehaviourPop);
+				default: throw new Exception("Unknown pop behaviour: " + this.OpCode.StackBehaviourPop);
 			}
 		}
 		
-		static int GetPushCount(MethodDefinition methodDef, ByteCode byteCode)
+		int GetPushCount()
 		{
-			switch(byteCode.OpCode.StackBehaviourPush) {
+			switch(this.OpCode.StackBehaviourPush) {
 				case StackBehaviour.Push0:       return 0;
 				case StackBehaviour.Push1:       return 1;
 				case StackBehaviour.Push1_push1: return 2;
@@ -103,9 +79,9 @@ namespace Decompiler
 				case StackBehaviour.Pushr8:      return 1;
 				case StackBehaviour.Pushref:     return 1;
 				case StackBehaviour.Varpush:     // Happens only for calls
-					switch(byteCode.OpCode.Code) {
+					switch(this.OpCode.Code) {
 						case Code.Call:     
-							Cecil.MethodReference cecilMethod = ((MethodReference)byteCode.Operand);
+							Cecil.MethodReference cecilMethod = ((MethodReference)this.Operand);
 							if (cecilMethod.ReturnType.ReturnType.FullName == Constants.Void) {
 								return 0;
 							} else {
@@ -115,7 +91,7 @@ namespace Decompiler
 						case Code.Callvirt: throw new NotImplementedException();
 						default: throw new Exception("Unknown Varpush opcode");
 					}
-				default: throw new Exception("Unknown push behaviour: " + byteCode.OpCode.StackBehaviourPush);
+				default: throw new Exception("Unknown push behaviour: " + this.OpCode.StackBehaviourPush);
 			}
 		}
 	}

src/ByteCode.cs

@@ -12,8 +12,6 @@ namespace Decompiler
 		ByteCode previous;
 		ByteCode next;
 		
-		List<ByteCode> nestedByteCodes = new List<ByteCode>();
-		
 		MethodDefinition methodDef;
 		int offset;
 		OpCode opCode;
@@ -29,10 +27,6 @@ namespace Decompiler
 			set { next = value; }
 		}
 		
-		public List<ByteCode> NestedByteCodes {
-			get { return nestedByteCodes; }
-		}
-		
 		public int Offset {
 			get { return offset; }
 			set { offset = value; }
@@ -68,5 +62,42 @@ namespace Decompiler
 			this.opCode = inst.OpCode;
 			this.operand = inst.Operand;
 		}
+		
+		public string Description {
+			get {
+				return string.Format(
+					" {1, -22} # {2}->{3} {4} {5}",
+					this.Offset,
+					this.OpCode + " " + FormatByteCodeOperand(this.Operand),
+					this.OpCode.StackBehaviourPop,
+					this.OpCode.StackBehaviourPush,
+					this.OpCode.FlowControl == FlowControl.Next ? string.Empty : "Flow=" + opCode.FlowControl,
+					this.OpCode.OpCodeType == OpCodeType.Macro ? "(macro)" : string.Empty
+				);
+			}
+		}
+		
+		static object FormatByteCodeOperand(object operand)
+		{
+			if (operand == null) {
+				return string.Empty;
+			} else if (operand is ByteCode) {
+				return string.Format("IL_{0:X2}", ((ByteCode)operand).Offset);
+			} else if (operand is MethodReference) {
+				return ((MethodReference)operand).Name + "()";
+			} else if (operand is Cecil.TypeReference) {
+				return ((Cecil.TypeReference)operand).FullName;
+			} else if (operand is VariableDefinition) {
+				return ((VariableDefinition)operand).Name;
+			} else if (operand is ParameterDefinition) {
+				return ((ParameterDefinition)operand).Name;
+			} else if (operand is string) {
+				return "\"" + operand + "\"";
+			} else if (operand is int) {
+				return operand.ToString();
+			} else {
+				return "(" + operand.GetType() + ")";
+			}
+		}
 	}
 }

src/CilStack.cs

@@ -75,6 +75,11 @@ namespace Decompiler
 			this.Add(slot);
 		}
 		
+		public CilStackSlot[] PeekCount(int count)
+		{
+			return this.GetRange(this.Count - count, count).ToArray();
+		}
+		
 		public CilStackSlot Peek(int depth)
 		{
 			return this[this.Count - depth];

src/StackExpression.cs

@@ -0,0 +1,86 @@
+using System;
+using System.Collections.Generic;
+
+using Cecil = Mono.Cecil;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+
+namespace Decompiler
+{
+	public class StackExpression
+	{
+		ByteCode expressionByteCode;
+		List<StackExpression> lastArguments = new List<StackExpression>();
+		
+		public ByteCode ExpressionByteCode {
+			get { return expressionByteCode; }
+		}
+		
+		public List<StackExpression> LastArguments {
+			get { return lastArguments; }
+		}
+		
+		public CilStack StackBefore {
+			get {
+				return this.FirstByteCode.StackBefore;
+			}
+		}
+		
+		public CilStack StackAfter {
+			get {
+				return this.ExpressionByteCode.StackAfter;
+			}
+		}
+		
+		public int PopCount {
+			get {
+				int popCount;
+				int pushCount;
+				SimulateStackSize(out popCount, out pushCount);
+				return popCount;
+			}
+		}
+		
+		public int PushCount {
+			get {
+				int popCount;
+				int pushCount;
+				SimulateStackSize(out popCount, out pushCount);
+				return pushCount;
+			}
+		}
+		
+		void SimulateStackSize(out int popCount, out int pushCount)
+		{
+			int stackSize = 0;
+			int minStackSize = 0;
+			foreach(StackExpression expr in lastArguments) {
+				stackSize -= expr.PopCount;
+				minStackSize = Math.Min(minStackSize, stackSize);
+				stackSize += expr.PushCount;
+			}
+			{
+				stackSize -= expressionByteCode.PopCount;
+				minStackSize = Math.Min(minStackSize, stackSize);
+				stackSize += expressionByteCode.PushCount;
+			}
+			popCount = -minStackSize;
+			pushCount = stackSize - minStackSize;
+		}
+		
+		public ByteCode FirstByteCode {
+			get {
+				if (lastArguments.Count > 0) {
+					return lastArguments[0].FirstByteCode;
+				} else {
+					return this.ExpressionByteCode;
+				}
+			}
+		}
+		
+		public StackExpression(ByteCode expressionByteCode)
+		{
+			this.expressionByteCode = expressionByteCode;
+		}
+	}
+}

src/StackExpressionCollection.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+
+using Cecil = Mono.Cecil;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+
+namespace Decompiler
+{
+	public class StackExpressionCollection: List<StackExpression>
+	{
+		public StackExpressionCollection(ByteCodeCollection byteCodeCol)
+		{
+			foreach(ByteCode bc in byteCodeCol) {
+				this.Add(new StackExpression(bc));
+			}
+		}
+		
+		public void Optimize()
+		{
+			
+		}
+	}
+}