First version of variable inlining.

Added ILAst SlotInfo.

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -44,6 +44,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			new OptimizingTransform(),
 			new LoopDetection(),
 			new ControlFlowSimplification(),
+			new ILInlining(),
 			new TransformingVisitor()
 		};
 
@@ -269,6 +270,8 @@ namespace ICSharpCode.Decompiler.CSharp
 			// insert variables at start of body
 			Statement prevVarDecl = null;
 			foreach (var v in function.Variables) {
+				if (v.LoadCount == 0 && v.StoreCount == 0 && v.AddressCount == 0)
+					continue;
 				if (v.Kind == VariableKind.Local || v.Kind == VariableKind.StackSlot) {
 					var type = typeSystemAstBuilder.ConvertType(v.Type);
 					var varDecl = new VariableDeclarationStatement(type, v.Name);

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -105,8 +105,10 @@
     <Compile Include="IL\Instructions\UnaryInstruction.cs" />
     <Compile Include="IL\IInlineContext.cs" />
     <Compile Include="IL\NRTypeExtensions.cs" />
+    <Compile Include="IL\SlotInfo.cs" />
     <Compile Include="IL\Transforms\ControlFlowSimplification.cs" />
     <Compile Include="IL\Transforms\IILTransform.cs" />
+    <Compile Include="IL\Transforms\ILInlining.cs" />
     <Compile Include="IL\Transforms\LoopDetection.cs" />
     <Compile Include="IL\Transforms\OptimizingTransform.cs" />
     <Compile Include="IL\Transforms\TransformingVisitor.cs" />

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -150,7 +150,8 @@ namespace ICSharpCode.Decompiler.IL
 		
 		/// <summary>
 		/// Warn when invalid IL is detected.
-		/// ILSpy should be able to handle invalid IL; but this method can be helpful for debugging the ILReader, as this method should not get called when processing valid IL.
+		/// ILSpy should be able to handle invalid IL; but this method can be helpful for debugging the ILReader,
+		/// as this method should not get called when processing valid IL.
 		/// </summary>
 		void Warn(string message)
 		{
@@ -207,6 +208,7 @@ namespace ICSharpCode.Decompiler.IL
 					Warn("Unknown result type (might be due to invalid IL)");
 				decodedInstruction.CheckInvariant();
 				decodedInstruction.ILRange = new Interval(start, reader.Position);
+				UnpackPush(decodedInstruction).ILRange = decodedInstruction.ILRange;
 				instructionBuilder.Add(decodedInstruction);
 				if (decodedInstruction.HasFlag(InstructionFlags.EndPointUnreachable)) {
 					if (!stackByOffset.TryGetValue(reader.Position, out currentStack)) {
@@ -269,6 +271,16 @@ namespace ICSharpCode.Decompiler.IL
 			return function;
 		}
 
+		static ILInstruction UnpackPush(ILInstruction inst)
+		{
+			ILVariable v;
+			ILInstruction inner;
+			if (inst.MatchStLoc(out v, out inner) && v.Kind == VariableKind.StackSlot)
+				return inner;
+			else
+				return inst;
+		}
+		
 		ILInstruction Neg()
 		{
 			switch (PeekStackType()) {
@@ -280,7 +292,7 @@ namespace ICSharpCode.Decompiler.IL
 				case StackType.F:
 					return Push(new Sub(new LdcF(0), Pop(), checkForOverflow: false, sign: Sign.None));
 				default:
-					Warn("Unsupported input type for neg: ");
+					Warn("Unsupported input type for neg.");
 					goto case StackType.I4;
 			}
 		}
@@ -669,14 +681,7 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Stsfld:
 					return new StsFld(Pop(), ReadAndDecodeFieldReference());
 				case ILOpCode.Ldtoken:
-					var memberReference = ReadAndDecodeMetadataToken() as MemberReference;
-					if (memberReference is TypeReference)
-						return new LdTypeToken(typeSystem.Resolve((TypeReference)memberReference));
-					if (memberReference is FieldReference)
-						return new LdMemberToken(typeSystem.Resolve((FieldReference)memberReference));
-					if (memberReference is MethodReference)
-						return new LdMemberToken(typeSystem.Resolve((MethodReference)memberReference));
-					throw new NotImplementedException();
+					return Push(LdToken(ReadAndDecodeMetadataToken()));
 				case ILOpCode.Ldvirtftn:
 					return Push(new LdVirtFtn(Pop(), ReadAndDecodeMethodReference()));
 				case ILOpCode.Mkrefany:
@@ -690,7 +695,7 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Rethrow:
 					return new Rethrow();
 				case ILOpCode.Sizeof:
-					return new SizeOf(ReadAndDecodeTypeReference());
+					return Push(new SizeOf(ReadAndDecodeTypeReference()));
 				case ILOpCode.Stelem:
 					return StElem(ReadAndDecodeTypeReference());
 				case ILOpCode.Stelem_I1:
@@ -780,19 +785,20 @@ namespace ICSharpCode.Decompiler.IL
 		ILInstruction Push(ILInstruction inst)
 		{
 			Debug.Assert(inst.ResultType != StackType.Void);
-			var v = new ILVariable(VariableKind.StackSlot, inst.ResultType, inst.ILRange.Start);
+			IType type = compilation.FindType(inst.ResultType.ToKnownTypeCode());
+			var v = new ILVariable(VariableKind.StackSlot, type, inst.ResultType, inst.ILRange.Start);
 			v.Name = "S_" + inst.ILRange.Start.ToString("x4");
 			currentStack = currentStack.Push(v);
 			return new StLoc(v, inst);
 		}
 		
-		IL.LdLoc Peek()
+		LdLoc Peek()
 		{
 			// TODO: handle stack underflow?
 			return new LdLoc(currentStack.Peek());
 		}
 		
-		IL.LdLoc Pop()
+		LdLoc Pop()
 		{
 			// TODO: handle stack underflow?
 			ILVariable v;
@@ -803,9 +809,9 @@ namespace ICSharpCode.Decompiler.IL
 		private ILInstruction Return()
 		{
 			if (body.Method.ReturnType.GetStackType() == StackType.Void)
-				return new ICSharpCode.Decompiler.IL.Return();
+				return new IL.Return();
 			else
-				return new ICSharpCode.Decompiler.IL.Return(Pop());
+				return new IL.Return(Pop());
 		}
 
 		private ILInstruction DecodeLdstr()
@@ -859,25 +865,29 @@ namespace ICSharpCode.Decompiler.IL
 
 		ILInstruction InitObj(ILInstruction target, IType type)
 		{
-			return new Void(new StObj(target, new DefaultValue(type), type));
+			return new StObj(target, new DefaultValue(type), type);
 		}
 		
 		private ILInstruction DecodeConstrainedCall()
 		{
 			var typeRef = ReadAndDecodeTypeReference();
 			var inst = DecodeInstruction();
-			var call = inst as CallInstruction;
+			var call = UnpackPush(inst) as CallInstruction;
 			if (call != null)
 				call.ConstrainedTo = typeRef;
+			else
+				Warn("Ignored invalid 'constrained' prefix");
 			return inst;
 		}
 
 		private ILInstruction DecodeTailCall()
 		{
 			var inst = DecodeInstruction();
-			var call = inst as CallInstruction;
+			var call = UnpackPush(inst) as CallInstruction;
 			if (call != null)
 				call.IsTail = true;
+			else
+				Warn("Ignored invalid 'tail' prefix");
 			return inst;
 		}
 
@@ -885,7 +895,7 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			byte alignment = reader.ReadByte();
 			var inst = DecodeInstruction();
-			var sup = inst as ISupportsUnalignedPrefix;
+			var sup = UnpackPush(inst) as ISupportsUnalignedPrefix;
 			if (sup != null)
 				sup.UnalignedPrefix = alignment;
 			else
@@ -896,7 +906,7 @@ namespace ICSharpCode.Decompiler.IL
 		private ILInstruction DecodeVolatile()
 		{
 			var inst = DecodeInstruction();
-			var svp = inst as ISupportsVolatilePrefix;
+			var svp = UnpackPush(inst) as ISupportsVolatilePrefix;
 			if (svp != null)
 				svp.IsVolatile = true;
 			else
@@ -907,7 +917,7 @@ namespace ICSharpCode.Decompiler.IL
 		private ILInstruction DecodeReadonly()
 		{
 			var inst = DecodeInstruction();
-			var ldelema = inst as LdElema;
+			var ldelema = UnpackPush(inst) as LdElema;
 			if (ldelema != null)
 				ldelema.IsReadOnly = true;
 			else
@@ -1043,5 +1053,16 @@ namespace ICSharpCode.Decompiler.IL
 			var left = Pop();
 			return Push(BinaryNumericInstruction.Create(opCode, left, right, checkForOverflow, sign));
 		}
+
+		ILInstruction LdToken(IMetadataTokenProvider token)
+		{
+			if (token is TypeReference)
+				return new LdTypeToken(typeSystem.Resolve((TypeReference)token));
+			if (token is FieldReference)
+				return new LdMemberToken(typeSystem.Resolve((FieldReference)token));
+			if (token is MethodReference)
+				return new LdMemberToken(typeSystem.Resolve((MethodReference)token));
+			throw new NotImplementedException();
+		}
 	}
 }

ICSharpCode.Decompiler/IL/ILVariable.cs

@@ -29,6 +29,10 @@ namespace ICSharpCode.Decompiler.IL
 		/// </summary>
 		Local,
 		/// <summary>
+		/// A pinned local variable
+		/// </summary>
+		PinnedLocal,
+		/// <summary>
 		/// A parameter.
 		/// </summary>
 		Parameter,
@@ -96,13 +100,11 @@ namespace ICSharpCode.Decompiler.IL
 			this.Index = index;
 		}
 		
-		public ILVariable(VariableKind kind, StackType type, int index)
+		public ILVariable(VariableKind kind, IType type, StackType stackType, int index)
 		{
-			if (type == null)
-				throw new ArgumentNullException("type");
 			this.Kind = kind;
-			this.Type = SpecialType.UnknownType;
-			this.StackType = type;
+			this.Type = type;
+			this.StackType = stackType;
 			this.Index = index;
 		}
 		
@@ -115,6 +117,8 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			output.WriteDefinition(this.Name, this, isLocal: true);
 			output.Write(" : ");
+			if (Kind == VariableKind.PinnedLocal)
+				output.Write("pinned ");
 			Type.WriteTo(output);
 			output.Write("({0} ldloc, {1} ldloca, {2} stloc)", LoadCount, AddressCount, StoreCount);
 		}

ICSharpCode.Decompiler/IL/InstructionFlags.cs

@@ -28,26 +28,6 @@ namespace ICSharpCode.Decompiler.IL
 	public enum InstructionFlags
 	{
 		None = 0,
-		/// <summary>
-		/// Phase-1 execution of this instruction may pop from the evaluation stack.
-		/// </summary>
-		MayPop   = 0x01,
-		/// <summary>
-		/// Phase-1 execution of this instruction may peek at the top-most element of the evaluation stack.
-		/// If MayPop is also set, this flag refers to the top-most element after an arbitrary number of pops.
-		/// </summary>
-		MayPeek  = 0x02,
-		/// <summary>
-		/// Phase-2 execution of this instruction may read the evaluation stack.
-		/// This is not set for instructions that access the stack only in phase-1.
-		/// </summary>
-		MayReadEvaluationStack = 0x04,
-		/// <summary>
-		/// Phase-2 execution of this instruction may modify the evaluation stack.
-		/// This is not set for instructions that access the stack only in phase-1.
-		/// </summary>
-		MayWriteEvaluationStack = 0x08,
-		
 		/// <summary>
 		/// The instruction may read from local variables.
 		/// </summary>

ICSharpCode.Decompiler/IL/Instructions.cs

@@ -102,6 +102,8 @@ namespace ICSharpCode.Decompiler.IL
 		LdLoca,
 		/// <summary>Stores a value into a local variable. (starg/stloc)</summary>
 		StLoc,
+		/// <summary>Stores the value into an anonymous temporary variable, and returns the address of that variable.</summary>
+		AddressOf,
 		/// <summary>Loads a constant string.</summary>
 		LdStr,
 		/// <summary>Loads a constant 32-bit integer.</summary>
@@ -172,6 +174,44 @@ namespace ICSharpCode.Decompiler.IL
 		LdElema,
 	}
 
+	/// <summary>Instruction without any arguments</summary>
+	public abstract partial class SimpleInstruction : ILInstruction
+	{
+		protected SimpleInstruction(OpCode opCode) : base(opCode)
+		{
+		}
+		protected sealed override int GetChildCount()
+		{
+			return 0;
+		}
+		protected sealed override ILInstruction GetChild(int index)
+		{
+			switch (index) {
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		protected sealed override void SetChild(int index, ILInstruction value)
+		{
+			switch (index) {
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		public sealed override ILInstruction Clone()
+		{
+			var clone = (SimpleInstruction)ShallowClone();
+			return clone;
+		}
+	}
+
 	/// <summary>Instruction with a single argument</summary>
 	public abstract partial class UnaryInstruction : ILInstruction
 	{
@@ -179,11 +219,12 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			this.Argument = argument;
 		}
+		public static readonly SlotInfo ArgumentSlot = new SlotInfo("Argument", canInlineInto: true);
 		ILInstruction argument;
 		public ILInstruction Argument {
 			get { return this.argument; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.argument, value, 0);
 			}
 		}
@@ -210,17 +251,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ArgumentSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (UnaryInstruction)ShallowClone();
 			clone.Argument = this.argument.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Argument = this.argument.Inline(flagsBefore, context);
-			return this;
-		}
 		protected override InstructionFlags ComputeFlags()
 		{
 			return argument.Flags;
@@ -242,19 +287,21 @@ namespace ICSharpCode.Decompiler.IL
 			this.Left = left;
 			this.Right = right;
 		}
+		public static readonly SlotInfo LeftSlot = new SlotInfo("Left", canInlineInto: true);
 		ILInstruction left;
 		public ILInstruction Left {
 			get { return this.left; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.left, value, 0);
 			}
 		}
+		public static readonly SlotInfo RightSlot = new SlotInfo("Right", canInlineInto: true);
 		ILInstruction right;
 		public ILInstruction Right {
 			get { return this.right; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.right, value, 1);
 			}
 		}
@@ -286,6 +333,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return LeftSlot;
+				case 1:
+					return RightSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (BinaryInstruction)ShallowClone();
@@ -293,12 +351,6 @@ namespace ICSharpCode.Decompiler.IL
 			clone.Right = this.right.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Right = this.right.Inline(flagsBefore | ((this.left.Flags) & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop)), context);
-			this.Left = this.left.Inline(flagsBefore, context);
-			return this;
-		}
 		protected override InstructionFlags ComputeFlags()
 		{
 			return left.Flags | right.Flags;
@@ -334,6 +386,7 @@ namespace ICSharpCode.Decompiler.IL
 	/// <summary>A container of IL blocks.</summary>
 	public sealed partial class ILFunction : ILInstruction
 	{
+		public static readonly SlotInfo BodySlot = new SlotInfo("Body");
 		ILInstruction body;
 		public ILInstruction Body {
 			get { return this.body; }
@@ -365,6 +418,15 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return BodySlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (ILFunction)ShallowClone();
@@ -636,14 +698,16 @@ namespace ICSharpCode.Decompiler.IL
 	/// <summary>If statement / conditional expression. <c>if (condition) trueExpr else falseExpr</c></summary>
 	public sealed partial class IfInstruction : ILInstruction
 	{
+		public static readonly SlotInfo ConditionSlot = new SlotInfo("Condition", canInlineInto: true);
 		ILInstruction condition;
 		public ILInstruction Condition {
 			get { return this.condition; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.condition, value, 0);
 			}
 		}
+		public static readonly SlotInfo TrueInstSlot = new SlotInfo("TrueInst");
 		ILInstruction trueInst;
 		public ILInstruction TrueInst {
 			get { return this.trueInst; }
@@ -652,6 +716,7 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.trueInst, value, 1);
 			}
 		}
+		public static readonly SlotInfo FalseInstSlot = new SlotInfo("FalseInst");
 		ILInstruction falseInst;
 		public ILInstruction FalseInst {
 			get { return this.falseInst; }
@@ -693,6 +758,19 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ConditionSlot;
+				case 1:
+					return TrueInstSlot;
+				case 2:
+					return FalseInstSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (IfInstruction)ShallowClone();
@@ -728,6 +806,7 @@ namespace ICSharpCode.Decompiler.IL
 	/// <summary>Switch section within a switch statement</summary>
 	public sealed partial class SwitchSection : ILInstruction
 	{
+		public static readonly SlotInfo BodySlot = new SlotInfo("Body");
 		ILInstruction body;
 		public ILInstruction Body {
 			get { return this.body; }
@@ -759,6 +838,15 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return BodySlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (SwitchSection)ShallowClone();
@@ -800,14 +888,16 @@ namespace ICSharpCode.Decompiler.IL
 			Debug.Assert(variable != null);
 			this.variable = variable;
 		}
+		public static readonly SlotInfo FilterSlot = new SlotInfo("Filter");
 		ILInstruction filter;
 		public ILInstruction Filter {
 			get { return this.filter; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.filter, value, 0);
 			}
 		}
+		public static readonly SlotInfo BodySlot = new SlotInfo("Body");
 		ILInstruction body;
 		public ILInstruction Body {
 			get { return this.body; }
@@ -844,6 +934,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return FilterSlot;
+				case 1:
+					return BodySlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (TryCatchHandler)ShallowClone();
@@ -1135,11 +1236,12 @@ namespace ICSharpCode.Decompiler.IL
 		readonly ILVariable variable;
 		/// <summary>Returns the variable operand.</summary>
 		public ILVariable Variable { get { return variable; } }
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
 		ILInstruction value;
 		public ILInstruction Value {
 			get { return this.value; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.value, value, 0);
 			}
 		}
@@ -1166,17 +1268,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ValueSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (StLoc)ShallowClone();
 			clone.Value = this.value.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Value = this.value.Inline(flagsBefore, context);
-			return this;
-		}
 		public override StackType ResultType { get { return variable.StackType; } }
 		protected override InstructionFlags ComputeFlags()
 		{
@@ -1201,6 +1307,82 @@ namespace ICSharpCode.Decompiler.IL
 		}
 	}
 
+	/// <summary>Stores the value into an anonymous temporary variable, and returns the address of that variable.</summary>
+	public sealed partial class AddressOf : ILInstruction
+	{
+		public AddressOf(ILInstruction value) : base(OpCode.AddressOf)
+		{
+			this.Value = value;
+		}
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
+		ILInstruction value;
+		public ILInstruction Value {
+			get { return this.value; }
+			set {
+				ValidateChild(value);
+				SetChildInstruction(ref this.value, value, 0);
+			}
+		}
+		protected sealed override int GetChildCount()
+		{
+			return 1;
+		}
+		protected sealed override ILInstruction GetChild(int index)
+		{
+			switch (index) {
+				case 0:
+					return this.value;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		protected sealed override void SetChild(int index, ILInstruction value)
+		{
+			switch (index) {
+				case 0:
+					this.Value = value;
+					break;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ValueSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
+		public sealed override ILInstruction Clone()
+		{
+			var clone = (AddressOf)ShallowClone();
+			clone.Value = this.value.Clone();
+			return clone;
+		}
+		public override StackType ResultType { get { return StackType.Ref; } }
+		protected override InstructionFlags ComputeFlags()
+		{
+			return value.Flags;
+		}
+		public override void WriteTo(ITextOutput output)
+		{
+			output.Write(OpCode);
+			output.Write('(');
+			this.value.WriteTo(output);
+			output.Write(')');
+		}
+		public override void AcceptVisitor(ILVisitor visitor)
+		{
+			visitor.VisitAddressOf(this);
+		}
+		public override T AcceptVisitor<T>(ILVisitor<T> visitor)
+		{
+			return visitor.VisitAddressOf(this);
+		}
+	}
+
 	/// <summary>Loads a constant string.</summary>
 	public sealed partial class LdStr : SimpleInstruction
 	{
@@ -1510,11 +1692,12 @@ namespace ICSharpCode.Decompiler.IL
 			this.Target = target;
 			this.field = field;
 		}
+		public static readonly SlotInfo TargetSlot = new SlotInfo("Target", canInlineInto: true);
 		ILInstruction target;
 		public ILInstruction Target {
 			get { return this.target; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.target, value, 0);
 			}
 		}
@@ -1541,17 +1724,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TargetSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (LdFld)ShallowClone();
 			clone.Target = this.target.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Target = this.target.Inline(flagsBefore, context);
-			return this;
-		}
 		/// <summary>Gets/Sets whether the memory access is volatile.</summary>
 		public bool IsVolatile { get; set; }
 		/// <summary>Returns the alignment specified by the 'unaligned' prefix; or 0 if there was no 'unaligned' prefix.</summary>
@@ -1595,11 +1782,12 @@ namespace ICSharpCode.Decompiler.IL
 			this.Target = target;
 			this.field = field;
 		}
+		public static readonly SlotInfo TargetSlot = new SlotInfo("Target", canInlineInto: true);
 		ILInstruction target;
 		public ILInstruction Target {
 			get { return this.target; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.target, value, 0);
 			}
 		}
@@ -1626,17 +1814,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TargetSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (LdFlda)ShallowClone();
 			clone.Target = this.target.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Target = this.target.Inline(flagsBefore, context);
-			return this;
-		}
 		readonly IField field;
 		/// <summary>Returns the field operand.</summary>
 		public IField Field { get { return field; } }
@@ -1673,19 +1865,21 @@ namespace ICSharpCode.Decompiler.IL
 			this.Value = value;
 			this.field = field;
 		}
+		public static readonly SlotInfo TargetSlot = new SlotInfo("Target", canInlineInto: true);
 		ILInstruction target;
 		public ILInstruction Target {
 			get { return this.target; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.target, value, 0);
 			}
 		}
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
 		ILInstruction value;
 		public ILInstruction Value {
 			get { return this.value; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.value, value, 1);
 			}
 		}
@@ -1717,6 +1911,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TargetSlot;
+				case 1:
+					return ValueSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (StFld)ShallowClone();
@@ -1724,12 +1929,6 @@ namespace ICSharpCode.Decompiler.IL
 			clone.Value = this.value.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Value = this.value.Inline(flagsBefore | ((this.target.Flags) & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop)), context);
-			this.Target = this.target.Inline(flagsBefore, context);
-			return this;
-		}
 		/// <summary>Gets/Sets whether the memory access is volatile.</summary>
 		public bool IsVolatile { get; set; }
 		/// <summary>Returns the alignment specified by the 'unaligned' prefix; or 0 if there was no 'unaligned' prefix.</summary>
@@ -1841,11 +2040,12 @@ namespace ICSharpCode.Decompiler.IL
 			this.Value = value;
 			this.field = field;
 		}
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
 		ILInstruction value;
 		public ILInstruction Value {
 			get { return this.value; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.value, value, 0);
 			}
 		}
@@ -1872,17 +2072,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ValueSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (StsFld)ShallowClone();
 			clone.Value = this.value.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Value = this.value.Inline(flagsBefore, context);
-			return this;
-		}
 		/// <summary>Gets/Sets whether the memory access is volatile.</summary>
 		public bool IsVolatile { get; set; }
 		/// <summary>Returns the alignment specified by the 'unaligned' prefix; or 0 if there was no 'unaligned' prefix.</summary>
@@ -1990,11 +2194,12 @@ namespace ICSharpCode.Decompiler.IL
 			this.Target = target;
 			this.type = type;
 		}
+		public static readonly SlotInfo TargetSlot = new SlotInfo("Target", canInlineInto: true);
 		ILInstruction target;
 		public ILInstruction Target {
 			get { return this.target; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.target, value, 0);
 			}
 		}
@@ -2021,17 +2226,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TargetSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (LdObj)ShallowClone();
 			clone.Target = this.target.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Target = this.target.Inline(flagsBefore, context);
-			return this;
-		}
 		readonly IType type;
 		/// <summary>Returns the type operand.</summary>
 		public IType Type { get { return type; } }
@@ -2076,19 +2285,21 @@ namespace ICSharpCode.Decompiler.IL
 			this.Value = value;
 			this.type = type;
 		}
+		public static readonly SlotInfo TargetSlot = new SlotInfo("Target", canInlineInto: true);
 		ILInstruction target;
 		public ILInstruction Target {
 			get { return this.target; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.target, value, 0);
 			}
 		}
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
 		ILInstruction value;
 		public ILInstruction Value {
 			get { return this.value; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.value, value, 1);
 			}
 		}
@@ -2120,6 +2331,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TargetSlot;
+				case 1:
+					return ValueSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (StObj)ShallowClone();
@@ -2127,12 +2349,6 @@ namespace ICSharpCode.Decompiler.IL
 			clone.Value = this.value.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Value = this.value.Inline(flagsBefore | ((this.target.Flags) & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop)), context);
-			this.Target = this.target.Inline(flagsBefore, context);
-			return this;
-		}
 		readonly IType type;
 		/// <summary>Returns the type operand.</summary>
 		public IType Type { get { return type; } }
@@ -2300,11 +2516,12 @@ namespace ICSharpCode.Decompiler.IL
 		readonly IType type;
 		/// <summary>Returns the type operand.</summary>
 		public IType Type { get { return type; } }
+		public static readonly SlotInfo SizeSlot = new SlotInfo("Size", canInlineInto: true);
 		ILInstruction size;
 		public ILInstruction Size {
 			get { return this.size; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.size, value, 0);
 			}
 		}
@@ -2331,17 +2548,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return SizeSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (NewArr)ShallowClone();
 			clone.Size = this.size.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Size = this.size.Inline(flagsBefore, context);
-			return this;
-		}
 		public override StackType ResultType { get { return StackType.O; } }
 		protected override InstructionFlags ComputeFlags()
 		{
@@ -2469,11 +2690,12 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			this.Array = array;
 		}
+		public static readonly SlotInfo ArraySlot = new SlotInfo("Array", canInlineInto: true);
 		ILInstruction array;
 		public ILInstruction Array {
 			get { return this.array; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.array, value, 0);
 			}
 		}
@@ -2500,17 +2722,21 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ArraySlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (LdLen)ShallowClone();
 			clone.Array = this.array.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Array = this.array.Inline(flagsBefore, context);
-			return this;
-		}
 		public override StackType ResultType { get { return StackType.I; } }
 		protected override InstructionFlags ComputeFlags()
 		{
@@ -2542,19 +2768,21 @@ namespace ICSharpCode.Decompiler.IL
 			this.Index = index;
 			this.type = type;
 		}
+		public static readonly SlotInfo ArraySlot = new SlotInfo("Array", canInlineInto: true);
 		ILInstruction array;
 		public ILInstruction Array {
 			get { return this.array; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.array, value, 0);
 			}
 		}
+		public static readonly SlotInfo IndexSlot = new SlotInfo("Index", canInlineInto: true);
 		ILInstruction index;
 		public ILInstruction Index {
 			get { return this.index; }
 			set {
-				ValidateArgument(value);
+				ValidateChild(value);
 				SetChildInstruction(ref this.index, value, 1);
 			}
 		}
@@ -2586,6 +2814,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		protected sealed override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return ArraySlot;
+				case 1:
+					return IndexSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 		public sealed override ILInstruction Clone()
 		{
 			var clone = (LdElema)ShallowClone();
@@ -2593,12 +2832,6 @@ namespace ICSharpCode.Decompiler.IL
 			clone.Index = this.index.Clone();
 			return clone;
 		}
-		internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Index = this.index.Inline(flagsBefore | ((this.array.Flags) & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop)), context);
-			this.Array = this.array.Inline(flagsBefore, context);
-			return this;
-		}
 		readonly IType type;
 		/// <summary>Returns the type operand.</summary>
 		public IType Type { get { return type; } }
@@ -2789,6 +3022,10 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			Default(inst);
 		}
+		protected internal virtual void VisitAddressOf(AddressOf inst)
+		{
+			Default(inst);
+		}
 		protected internal virtual void VisitLdStr(LdStr inst)
 		{
 			Default(inst);
@@ -3083,6 +3320,10 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			return Default(inst);
 		}
+		protected internal virtual T VisitAddressOf(AddressOf inst)
+		{
+			return Default(inst);
+		}
 		protected internal virtual T VisitLdStr(LdStr inst)
 		{
 			return Default(inst);
@@ -3313,6 +3554,7 @@ namespace ICSharpCode.Decompiler.IL
 			"ldloc",
 			"ldloca",
 			"stloc",
+			"addressof",
 			"ldstr",
 			"ldc.i4",
 			"ldc.i8",
@@ -3608,6 +3850,16 @@ namespace ICSharpCode.Decompiler.IL
 			value = default(ILInstruction);
 			return false;
 		}
+		public bool MatchAddressOf(out ILInstruction value)
+		{
+			var inst = this as AddressOf;
+			if (inst != null) {
+				value = inst.Value;
+				return true;
+			}
+			value = default(ILInstruction);
+			return false;
+		}
 		public bool MatchLdStr(out string value)
 		{
 			var inst = this as LdStr;

ICSharpCode.Decompiler/IL/Instructions.tt

@@ -24,6 +24,8 @@
 <#@ output extension=".cs" #>
 <#
 	OpCode[] baseClasses = {
+		new OpCode("SimpleInstruction", "Instruction without any arguments",
+			AbstractBaseClass, CustomArguments(), CustomWriteTo),
 		new OpCode("UnaryInstruction", "Instruction with a single argument",
 			AbstractBaseClass, CustomArguments("argument")),
 		new OpCode("BinaryInstruction", "Instruction with two arguments: Left and Right",
@@ -60,7 +62,7 @@
 		new OpCode("if", "If statement / conditional expression. <c>if (condition) trueExpr else falseExpr</c>",
 			CustomClassName("IfInstruction"),
 			CustomChildren(new []{
-				new ChildInfo("condition") { IsArgument = true },
+				new ArgumentInfo("condition"),
 				new ChildInfo("trueInst"),
 				new ChildInfo("falseInst"),
 			}), CustomConstructor, CustomComputeFlags, CustomWriteTo),
@@ -73,7 +75,7 @@
 			BaseClass("TryInstruction"), CustomConstructor, CustomComputeFlags, CustomWriteTo),
 		new OpCode("try.catch.handler", "Catch handler within a try-catch statement.",
 			CustomChildren(new [] {
-				new ChildInfo("filter") { IsArgument = true },
+				new ChildInfo("filter"),
 				new ChildInfo("body"),
 			}), HasVariableOperand, CustomWriteTo, CustomComputeFlags),
 		new OpCode("try.finally", "Try-finally statement",
@@ -106,6 +108,9 @@
 		new OpCode("stloc", "Stores a value into a local variable. (starg/stloc)",
 			CustomClassName("StLoc"), HasVariableOperand, CustomArguments("value"),
 			ResultType("variable.StackType")),
+		new OpCode("addressof", "Stores the value into an anonymous temporary variable, and returns the address of that variable.",
+			CustomClassName("AddressOf"), CustomArguments("value"), ResultType("Ref")),
+		
 		new OpCode("ldstr", "Loads a constant string.",
 			CustomClassName("LdStr"), LoadConstant("string"), ResultType("O")),
 		new OpCode("ldc.i4", "Loads a constant 32-bit integer.",
@@ -557,19 +562,40 @@ namespace ICSharpCode.Decompiler.IL
 
 	static Action<OpCode> CustomArguments(params string[] arguments)
 	{
-		return CustomChildren(arguments.Select(arg => new ChildInfo(arg) { IsArgument = true}).ToArray(), generateInline: true);
+		return CustomChildren(arguments.Select(arg => new ArgumentInfo(arg)).ToArray(), generateInline: true);
 	}
 	
 	class ChildInfo
 	{
 		public readonly string PropertyName;
 		public readonly string Name;
-		public bool IsArgument;
+		public readonly string SlotName;
+		
+		public bool CanInlineInto;
 		
 		public ChildInfo(string name)
 		{
 			this.Name = name;
 			this.PropertyName = MakeName(name);
+			this.SlotName = this.PropertyName + "Slot";
+		}
+		
+		public string GetSlotInit()
+		{
+			StringBuilder b = new StringBuilder();
+			b.Append("new SlotInfo(\"" + PropertyName + "\"");
+			if (CanInlineInto)
+				b.Append(", canInlineInto: true");
+			b.Append(")");
+			return b.ToString();
+		}
+	}
+	
+	class ArgumentInfo : ChildInfo
+	{
+		public ArgumentInfo(string name) : base(name)
+		{
+			this.CanInlineInto = true;
 		}
 	}
 	
@@ -589,11 +615,12 @@ namespace ICSharpCode.Decompiler.IL
 				if (i > 0)
 					opCode.WriteArguments.Add("output.Write(\", \");");
 				opCode.WriteArguments.Add("this." + arg + ".WriteTo(output);");
+				opCode.Members.Add("public static readonly SlotInfo " + children[i].SlotName + " = " + children[i].GetSlotInit() + ";");
 				opCode.Members.Add("ILInstruction " + arg + ";");
 				opCode.Members.Add("public ILInstruction " + argProp + " {" + Environment.NewLine
 					+ "\tget { return this." + arg + "; }" + Environment.NewLine
 					+ "\tset {" + Environment.NewLine
-					+ "\t\t" + (children[i].IsArgument ? "ValidateArgument" : "ValidateChild") + "(value);" + Environment.NewLine
+					+ "\t\tValidateChild(value);" + Environment.NewLine
 					+ "\t\tSetChildInstruction(ref this." + arg + ", value, " + i + ");" + Environment.NewLine
 					+ "\t}" + Environment.NewLine
 					+ "}");
@@ -636,6 +663,20 @@ namespace ICSharpCode.Decompiler.IL
 			b.Append("}");
 			opCode.Members.Add(b.ToString());
 			
+			b = new StringBuilder();
+			b.AppendLine("protected sealed override SlotInfo GetChildSlot(int index)");
+			b.AppendLine("{");
+			b.AppendLine("\tswitch (index) {");
+			for (int i = 0; i < children.Length; i++) {
+				b.AppendLine("\t\tcase " + i + ":");
+				b.AppendLine("\t\t\treturn " + children[i].SlotName + ";");
+			}
+			b.AppendLine("\t\tdefault:");
+			b.AppendLine("\t\t\tthrow new IndexOutOfRangeException();");
+			b.AppendLine("\t}");
+			b.Append("}");
+			opCode.Members.Add(b.ToString());
+			
 			b = new StringBuilder();
 			b.AppendLine("public sealed override ILInstruction Clone()");
 			b.AppendLine("{");
@@ -646,25 +687,6 @@ namespace ICSharpCode.Decompiler.IL
 			b.AppendLine("\treturn clone;");
 			b.Append("}");
 			opCode.Members.Add(b.ToString());
-			
-			if (generateInline) {
-				b = new StringBuilder();
-				b.AppendLine("internal sealed override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)");
-				b.AppendLine("{");
-				for (int i = children.Length - 1; i >= 0; i--) {
-					string arg = children[i].Name;
-					b.Append("\tthis." + MakeName(arg) + " = this." + arg + ".Inline(flagsBefore");
-					if (i > 0) {
-						b.Append(" | ((");
-						b.Append(string.Join(" | ", children.Take(i).Select(child2 => "this." + child2.Name + ".Flags")));
-						b.Append(") & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop))");
-					}
-					b.AppendLine(", context);");
-				}
-				b.AppendLine("\treturn this;");
-				b.Append("}");
-				opCode.Members.Add(b.ToString());
-			}
 		};
 	}
 

ICSharpCode.Decompiler/IL/Instructions/Block.cs

@@ -30,35 +30,22 @@ namespace ICSharpCode.Decompiler.IL
 {
 	/// <summary>
 	/// A block consists of a list of IL instructions.
-	/// <para>
-	/// Phase-1 execution of a block is a no-op: any peek/pop instructions within the block are ignored at this stage.
-	/// </para>
-	/// <para>
-	/// Phase-2 execution will execute the instructions in order, pseudo-code:
-	/// </para>
-	/// <code>
-	///   foreach (var inst in Instructions) {
-	///     var result = inst.Phase1().Phase2();
-	///     if (result != void) evalStack.Push(result);
-	///   }
-	///   return FinalInstruction.Phase1().Phase2();
-	/// </code>
+	/// 
 	/// <para>
 	/// Note: if execution reaches the end of the instruction list,
 	/// the FinalInstruction (which is not part of the list) will be executed.
 	/// The block returns returns the result value of the FinalInstruction.
 	/// For blocks returning void, the FinalInstruction will usually be 'nop'.
+	/// 
+	/// TODO: now that 'implicit push' is gone, reconsider whether we need
+	/// a separate slot for FinalInstruction
 	/// </para>
 	/// </summary>
-	/// <remarks>
-	/// Fun fact: wrapping a pop instruction in a block
-	/// (<c>new Block { FinalInstruction = popInst }</c>) turns it
-	/// from a phase-1 pop instruction to a phase-2 pop instruction.
-	/// However, this is just of theoretical interest; we currently don't plan to use inline blocks that
-	/// pop elements that they didn't push themselves.
-	/// </remarks>
 	partial class Block : ILInstruction
 	{
+		public static readonly SlotInfo InstructionSlot = new SlotInfo("Instruction", isCollection: true);
+		public static readonly SlotInfo FinalInstructionSlot = new SlotInfo("FinalInstruction");
+		
 		public readonly InstructionCollection<ILInstruction> Instructions;
 		ILInstruction finalInstruction;
 		
@@ -168,15 +155,19 @@ namespace ICSharpCode.Decompiler.IL
 				Instructions[index] = value;
 		}
 		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			if (index == Instructions.Count)
+				return InstructionSlot;
+			else
+				return FinalInstructionSlot;
+		}
+		
 		protected override InstructionFlags ComputeFlags()
 		{
 			var flags = InstructionFlags.None;
 			foreach (var inst in Instructions) {
 				flags |= Phase1Boundary(inst.Flags);
-				if (inst.ResultType != StackType.Void) {
-					// implicit push
-					flags |= InstructionFlags.MayWriteEvaluationStack;
-				}
 			}
 			flags |= Phase1Boundary(FinalInstruction.Flags);
 			return flags;
@@ -187,16 +178,10 @@ namespace ICSharpCode.Decompiler.IL
 		/// The MayPop and MayPeek flags are removed and converted into
 		/// MayReadEvaluationStack and/or MayWriteEvaluationStack flags.
 		/// </summary>
-		[Obsolete("there's not phase-1 evaluation anymore")]
+		[Obsolete("there's no phase-1 evaluation anymore")]
 		internal static InstructionFlags Phase1Boundary(InstructionFlags flags)
 		{
 			return flags;
 		}
-		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// an inline block has no phase-1 effects, so we're immediately done with inlining
-			return this;
-		}
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/BlockContainer.cs

@@ -38,6 +38,7 @@ namespace ICSharpCode.Decompiler.IL
 	/// </summary>
 	partial class BlockContainer : ILInstruction
 	{
+		public readonly SlotInfo BlockSlot = new SlotInfo("Block", isCollection: true);
 		public readonly InstructionCollection<Block> Blocks;
 		
 		/// <summary>
@@ -133,6 +134,11 @@ namespace ICSharpCode.Decompiler.IL
 				throw new InvalidOperationException("Cannot replace blocks in BlockContainer");
 		}
 
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			return BlockSlot;
+		}
+
 		internal override void CheckInvariant()
 		{
 			base.CheckInvariant();
@@ -154,12 +160,6 @@ namespace ICSharpCode.Decompiler.IL
 				flags &= ~InstructionFlags.EndPointUnreachable;
 			return flags;
 		}
-		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// Blocks are phase-1 boundaries
-			return this;
-		}
 	}
 }
 

ICSharpCode.Decompiler/IL/Instructions/CallInstruction.cs

@@ -29,6 +29,8 @@ namespace ICSharpCode.Decompiler.IL
 {
 	public abstract class CallInstruction : ILInstruction
 	{
+		public static readonly SlotInfo ArgumentSlot = new SlotInfo("Argument", canInlineInto: true, isCollection: true);
+		
 		public static CallInstruction Create(OpCode opCode, IMethod method)
 		{
 			switch (opCode) {
@@ -98,6 +100,11 @@ namespace ICSharpCode.Decompiler.IL
 			Arguments[index] = value;
 		}
 		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			return ArgumentSlot;
+		}
+		
 		protected override InstructionFlags ComputeFlags()
 		{
 			var flags = InstructionFlags.MayThrow | InstructionFlags.SideEffect;
@@ -125,18 +132,5 @@ namespace ICSharpCode.Decompiler.IL
 			}
 			output.Write(')');
 		}
-
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			InstructionFlags operandFlags = InstructionFlags.None;
-			for (int i = 0; i < Arguments.Count - 1; i++) {
-				operandFlags |= Arguments[i].Flags;
-			}
-			flagsBefore |= operandFlags & ~(InstructionFlags.MayPeek | InstructionFlags.MayPop);
-			for (int i = Arguments.Count - 1; i >= 0; i--) {
-				Arguments[i] = Arguments[i].Inline(flagsBefore, context);
-			}
-			return this;
-		}
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/ILFunction.cs

@@ -62,11 +62,5 @@ namespace ICSharpCode.Decompiler.IL
 			// We intentionally don't propagate any flags from the lambda body!
 			return InstructionFlags.MayThrow;
 		}
-		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// To the outside, lambda creation looks like a constant
-			return this;
-		}
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/ILInstruction.cs

@@ -39,15 +39,6 @@ namespace ICSharpCode.Decompiler.IL
 			this.OpCode = opCode;
 		}
 		
-		protected void ValidateArgument(ILInstruction inst)
-		{
-			if (inst == null)
-				throw new ArgumentNullException("inst");
-			if (inst.ResultType == StackType.Void)
-				throw new ArgumentException("Argument must not be of type void", "inst");
-			Debug.Assert(!this.IsDescendantOf(inst), "ILAst must form a tree");
-		}
-		
 		protected void ValidateChild(ILInstruction inst)
 		{
 			if (inst == null)
@@ -128,6 +119,12 @@ namespace ICSharpCode.Decompiler.IL
 		/// </summary>
 		public Interval ILRange;
 
+		public void AddILRange(Interval ilRange)
+		{
+			// TODO: try to combine the two ranges
+			this.ILRange = ilRange;
+		}
+
 		/// <summary>
 		/// Writes the ILAst to the text output.
 		/// </summary>
@@ -162,6 +159,7 @@ namespace ICSharpCode.Decompiler.IL
 		protected abstract int GetChildCount();
 		protected abstract ILInstruction GetChild(int index);
 		protected abstract void SetChild(int index, ILInstruction value);
+		protected abstract SlotInfo GetChildSlot(int index);
 		
 		#region ChildrenCollection + ChildrenEnumerator
 		public struct ChildrenCollection : IReadOnlyList<ILInstruction>
@@ -290,6 +288,7 @@ namespace ICSharpCode.Decompiler.IL
 		
 		/// <summary>
 		/// Returns all descendants of the ILInstruction in post-order.
+		/// (including the ILInstruction itself)
 		/// </summary>
 		/// <remarks>
 		/// Within a loop 'foreach (var node in inst.Descendants)', it is illegal to
@@ -324,26 +323,10 @@ namespace ICSharpCode.Decompiler.IL
 						stack.Pop().Dispose();
 					}
 				}
+				yield return this;
 			}
 		}
 		
-		/// <summary>
-		/// Attempts inlining from the inline context into this instruction.
-		/// </summary>
-		/// <param name="flagsBefore">Combined instruction flags of the instructions
-		/// that the instructions getting inlined would get moved over.</param>
-		/// <param name="context">The inline context providing the values on the evaluation stack.</param>
-		/// <returns>
-		/// Returns the modified ILInstruction after inlining is complete.
-		/// Note that inlining modifies the AST in-place, so this method usually returns <c>this</c>
-		/// (unless <c>this</c> should be replaced by another node)
-		/// </returns>
-		/// <remarks>
-		/// Inlining from an inline context representing the actual evaluation stack
-		/// is equivalent to phase-1 execution of the instruction.
-		/// </remarks>
-		internal abstract ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context);
-
 		/// <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
@@ -405,6 +388,16 @@ namespace ICSharpCode.Decompiler.IL
 		/// </summary>
 		public int ChildIndex { get; internal set; }
 		
+		/// <summary>
+		/// Gets information about the slot in which this instruction is stored.
+		/// (i.e., the relation of this instruction to its parent instruction)
+		/// </summary>
+		public SlotInfo SlotInfo {
+			get {
+				return parent.GetChildSlot(this.ChildIndex);
+			}
+		}
+		
 		/// <summary>
 		/// Replaces a child of this ILInstruction.
 		/// </summary>

ICSharpCode.Decompiler/IL/Instructions/IfInstruction.cs

@@ -52,13 +52,6 @@ namespace ICSharpCode.Decompiler.IL
 			}
 		}
 		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			this.Condition = condition.Inline(flagsBefore, context);
-			// note: we skip TrueInst and FalseInst because there's a phase-1-boundary around them
-			return this;
-		}
-		
 		protected override InstructionFlags ComputeFlags()
 		{
 			return condition.Flags | Block.Phase1Boundary(CombineFlags(trueInst.Flags, falseInst.Flags));

ICSharpCode.Decompiler/IL/Instructions/PatternMatching.cs

@@ -33,32 +33,36 @@ namespace ICSharpCode.Decompiler.IL
 			return inst != null && inst.Variable == variable;
 		}
 		
+		public bool MatchLdLoca(ILVariable variable)
+		{
+			var inst = this as LdLoca;
+			return inst != null && inst.Variable == variable;
+		}
+		
 		public bool MatchLdThis()
 		{
 			var inst = this as LdLoc;
 			return inst != null && inst.Variable.Kind == VariableKind.This;
 		}
 		
-		public bool MatchStLoc(ILVariable variable, out ILInstruction value)
+		public bool MatchStLoc(out ILVariable variable)
 		{
 			var inst = this as StLoc;
-			if (inst != null && inst.Variable == variable) {
-				value = inst.Value;
+			if (inst != null) {
+				variable = inst.Variable;
 				return true;
 			}
-			value = null;
+			variable = null;
 			return false;
 		}
 		
-		public bool MatchStLoc(out ILVariable variable, out ILInstruction value)
+		public bool MatchStLoc(ILVariable variable, out ILInstruction value)
 		{
 			var inst = this as StLoc;
-			if (inst != null) {
-				variable = inst.Variable;
+			if (inst != null && inst.Variable == variable) {
 				value = inst.Value;
 				return true;
 			}
-			variable = null;
 			value = null;
 			return false;
 		}

ICSharpCode.Decompiler/IL/Instructions/Return.cs

@@ -24,6 +24,8 @@ namespace ICSharpCode.Decompiler.IL
 {
 	partial class Return
 	{
+		public static readonly SlotInfo ReturnValueSlot = new SlotInfo("ReturnValue", canInlineInto: true);
+		
 		ILInstruction returnValue;
 		
 		/// <summary>
@@ -33,7 +35,7 @@ namespace ICSharpCode.Decompiler.IL
 			get { return returnValue; }
 			set {
 				if (value != null)
-					ValidateArgument(value);
+					ValidateChild(value);
 				SetChildInstruction(ref returnValue, value, 0);
 			}
 		}
@@ -95,11 +97,9 @@ namespace ICSharpCode.Decompiler.IL
 				throw new IndexOutOfRangeException();
 		}
 		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
+		protected override SlotInfo GetChildSlot(int index)
 		{
-			if (returnValue != null)
-				this.ReturnValue = returnValue.Inline(flagsBefore, context);
-			return this;
+			return ReturnValueSlot;
 		}
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/SimpleInstruction.cs

@@ -28,46 +28,16 @@ namespace ICSharpCode.Decompiler.IL
 	/// <summary>
 	/// A simple instruction that does not have any arguments.
 	/// </summary>
-	public abstract class SimpleInstruction : ILInstruction
+	public abstract partial class SimpleInstruction : ILInstruction
 	{
-		protected SimpleInstruction(OpCode opCode) : base(opCode)
-		{
-		}
-		
 		public override void WriteTo(ITextOutput output)
 		{
 			output.Write(OpCode);
 		}
 		
-		protected sealed override int GetChildCount()
-		{
-			return 0;
-		}
-		
-		protected sealed override ILInstruction GetChild(int index)
-		{
-			throw new IndexOutOfRangeException();
-		}
-		
-		protected sealed override void SetChild(int index, ILInstruction value)
-		{
-			throw new IndexOutOfRangeException();
-		}
-		
-		public sealed override ILInstruction Clone()
-		{
-			return ShallowClone();
-		}
-		
 		protected override InstructionFlags ComputeFlags()
 		{
 			return InstructionFlags.None;
 		}
-		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// Nothing to do, since we don't have arguments.
-			return this;
-		}
 	}
 }

ICSharpCode.Decompiler/IL/Instructions/SwitchInstruction.cs

@@ -26,6 +26,9 @@ namespace ICSharpCode.Decompiler.IL
 	/// </summary>
 	partial class SwitchInstruction
 	{
+		public static readonly SlotInfo ValueSlot = new SlotInfo("Value", canInlineInto: true);
+		public static readonly SlotInfo SectionSlot = new SlotInfo("Section", isCollection: true);
+		
 		public SwitchInstruction(ILInstruction value)
 			: base(OpCode.SwitchInstruction)
 		{
@@ -44,12 +47,6 @@ namespace ICSharpCode.Decompiler.IL
 		
 		public readonly InstructionCollection<SwitchSection> Sections;
 		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			Value = value.Inline(flagsBefore, context);
-			return this;
-		}
-		
 		protected override InstructionFlags ComputeFlags()
 		{
 			var sectionFlags = InstructionFlags.None;
@@ -93,6 +90,13 @@ namespace ICSharpCode.Decompiler.IL
 				Sections[index - 1] = (SwitchSection)value;
 		}
 		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			if (index == 0)
+				return ValueSlot;
+			return SectionSlot;
+		}
+		
 		public override ILInstruction Clone()
 		{
 			var clone = new SwitchInstruction(value.Clone());
@@ -113,14 +117,6 @@ namespace ICSharpCode.Decompiler.IL
 
 		public LongSet Labels { get; set; }
 		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// Inlining into switch sections would be madness.
-			// To keep phase-1 execution semantics consistent with inlining, there's a
-			// phase-1-boundary around every switch section.
-			return this;
-		}
-		
 		protected override InstructionFlags ComputeFlags()
 		{
 			return Block.Phase1Boundary(body.Flags);

ICSharpCode.Decompiler/IL/Instructions/TryInstruction.cs

@@ -25,6 +25,8 @@ namespace ICSharpCode.Decompiler.IL
 {
 	public abstract class TryInstruction : ILInstruction
 	{
+		public static readonly SlotInfo TryBlockSlot = new SlotInfo("TryBlock");
+		
 		protected TryInstruction(OpCode opCode, ILInstruction tryBlock) : base(opCode)
 		{
 			this.TryBlock = tryBlock;
@@ -38,14 +40,6 @@ namespace ICSharpCode.Decompiler.IL
 				SetChildInstruction(ref this.tryBlock, value, 0);
 			}
 		}
-		
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// Inlining into exception-handling constructs would be madness.
-			// To keep phase-1 execution semantics consistent with inlining, there's a
-			// phase-1-boundary around every try/catch/finally/fault block.
-			return this;
-		}
 	}
 	
 	/// <summary>
@@ -58,6 +52,7 @@ namespace ICSharpCode.Decompiler.IL
 	/// </remarks>
 	partial class TryCatch : TryInstruction
 	{
+		public static readonly SlotInfo HandlerSlot = new SlotInfo("Handler", isCollection: true);
 		public readonly InstructionCollection<TryCatchHandler> Handlers;
 		
 		public TryCatch(ILInstruction tryBlock) : base(OpCode.TryCatch, tryBlock)
@@ -115,6 +110,14 @@ namespace ICSharpCode.Decompiler.IL
 			else
 				Handlers[index - 1] = (TryCatchHandler)value;
 		}
+		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			if (index == 0)
+				return TryBlockSlot;
+			else
+				return HandlerSlot;
+		}
 	}
 	
 	/// <summary>
@@ -131,12 +134,6 @@ namespace ICSharpCode.Decompiler.IL
 	/// </summary>
 	partial class TryCatchHandler
 	{
-		internal override ILInstruction Inline(InstructionFlags flagsBefore, IInlineContext context)
-		{
-			// should never happen as TryCatchHandler only appears within TryCatch instructions
-			throw new InvalidOperationException();
-		}
-		
 		internal override void CheckInvariant()
 		{
 			base.CheckInvariant();
@@ -183,6 +180,8 @@ namespace ICSharpCode.Decompiler.IL
 	
 	partial class TryFinally
 	{
+		public static readonly SlotInfo FinallyBlockSlot = new SlotInfo("FinallyBlock");
+		
 		public TryFinally(ILInstruction tryBlock, ILInstruction finallyBlock) : base(OpCode.TryFinally, tryBlock)
 		{
 			this.FinallyBlock = finallyBlock;
@@ -254,10 +253,24 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TryBlockSlot;
+				case 1:
+					return FinallyBlockSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 	}
 	
 	partial class TryFault
 	{
+		public static readonly SlotInfo FaultBlockSlot = new SlotInfo("FaultBlock");
+		
 		public TryFault(ILInstruction tryBlock, ILInstruction faultBlock) : base(OpCode.TryFinally, tryBlock)
 		{
 			this.FaultBlock = faultBlock;
@@ -328,5 +341,17 @@ namespace ICSharpCode.Decompiler.IL
 					throw new IndexOutOfRangeException();
 			}
 		}
+		
+		protected override SlotInfo GetChildSlot(int index)
+		{
+			switch (index) {
+				case 0:
+					return TryBlockSlot;
+				case 1:
+					return FaultBlockSlot;
+				default:
+					throw new IndexOutOfRangeException();
+			}
+		}
 	}
 }

ICSharpCode.Decompiler/IL/SemanticHelper.cs

@@ -24,23 +24,27 @@ namespace ICSharpCode.Decompiler.IL
 	{
 		// TODO: consider moving IfInstruction.CombineFlags and Block.Phase1Boundary here
 		
+		/// <summary>
+		/// Gets whether instruction is pure:
+		/// * must not have side effects
+		/// * must not throw exceptions
+		/// * must not branch
+		/// </summary>
+		internal static bool IsPure(InstructionFlags inst)
+		{
+			const InstructionFlags pureFlags = InstructionFlags.MayReadLocals;
+			return (inst & ~pureFlags) == 0;
+		}
+		
 		/// <summary>
 		/// Gets whether the instruction sequence 'inst1; inst2;' may be ordered to 'inst2; inst1;'
 		/// </summary>
 		internal static bool MayReorder(InstructionFlags inst1, InstructionFlags inst2)
 		{
 			// If both instructions perform an impure action, we cannot reorder them
-			const InstructionFlags pureFlags =
-				InstructionFlags.MayPeek
-				| InstructionFlags.MayReadEvaluationStack
-				| InstructionFlags.MayReadLocals;
-			if ((inst1 & inst2 & ~pureFlags) != 0)
-				return false;
-			// We cannot reorder if inst2 might pop what inst1 peeks at
-			if (ConflictingPair(inst1, inst2, InstructionFlags.MayPeek, InstructionFlags.MayPop))
-				return false;
-			if (ConflictingPair(inst1, inst2, InstructionFlags.MayReadEvaluationStack, InstructionFlags.MayWriteEvaluationStack))
+			if (!IsPure(inst1) && !IsPure(inst2))
 				return false;
+			// We cannot reorder if inst2 might write what inst1 looks at
 			if (ConflictingPair(inst1, inst2, InstructionFlags.MayReadLocals, InstructionFlags.MayWriteLocals | InstructionFlags.SideEffect))
 				return false;
 			return true;

ICSharpCode.Decompiler/IL/SlotInfo.cs

@@ -0,0 +1,44 @@
+/*
+ * Created by SharpDevelop.
+ * User: Daniel
+ * Date: 2015-05-31
+ * Time: 14:26
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+using System;
+
+namespace ICSharpCode.Decompiler.IL
+{
+	/// <summary>
+	/// Holds information about the role of an instruction within its parent instruction.
+	/// </summary>
+	public class SlotInfo
+	{
+		public static SlotInfo None = new SlotInfo("<no slot>");
+		
+		/// <summary>
+		/// Gets the name of the slot.
+		/// </summary>
+		public readonly string Name;
+		
+		/// <summary>
+		/// Gets whether it is possible to inline into this slot.
+		/// </summary>
+		public readonly bool CanInlineInto;
+
+		public readonly bool IsCollection;
+		
+		public SlotInfo(string name, bool canInlineInto = false, bool isCollection = false)
+		{
+			this.IsCollection = isCollection;
+			this.Name = name;
+			this.CanInlineInto = canInlineInto;
+		}
+		
+		public override string ToString()
+		{
+			return Name;
+		}
+	}
+}

ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs

@@ -1,4 +1,4 @@
-// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
+// Copyright (c) 2011-2015 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
@@ -21,121 +21,31 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using Mono.Cecil;
+using ICSharpCode.Decompiler.IL;
 
-namespace ICSharpCode.Decompiler.ILAst
+namespace ICSharpCode.Decompiler.IL
 {
 	/// <summary>
 	/// Performs inlining transformations.
 	/// </summary>
-	public class ILInlining
+	public class ILInlining : IILTransform
 	{
-		readonly ILBlock method;
-		internal Dictionary<ILVariable, int> numStloc  = new Dictionary<ILVariable, int>();
-		internal Dictionary<ILVariable, int> numLdloc  = new Dictionary<ILVariable, int>();
-		internal Dictionary<ILVariable, int> numLdloca = new Dictionary<ILVariable, int>();
-		
-		public ILInlining(ILBlock method)
-		{
-			this.method = method;
-			AnalyzeMethod();
-		}
-		
-		void AnalyzeMethod()
-		{
-			numStloc.Clear();
-			numLdloc.Clear();
-			numLdloca.Clear();
-			
-			// Analyse the whole method
-			AnalyzeNode(method);
-		}
-		
-		/// <summary>
-		/// For each variable reference, adds <paramref name="direction"/> to the num* dicts.
-		/// Direction will be 1 for analysis, and -1 when removing a node from analysis.
-		/// </summary>
-		void AnalyzeNode(ILNode node, int direction = 1)
+		public void Run(ILFunction function, ILTransformContext context)
 		{
-			ILExpression expr = node as ILExpression;
-			if (expr != null) {
-				ILVariable locVar = expr.Operand as ILVariable;
-				if (locVar != null) {
-					if (expr.Code == ILCode.Stloc) {
-						numStloc[locVar] = numStloc.GetOrDefault(locVar) + direction;
-					} else if (expr.Code == ILCode.Ldloc) {
-						numLdloc[locVar] = numLdloc.GetOrDefault(locVar) + direction;
-					} else if (expr.Code == ILCode.Ldloca) {
-						numLdloca[locVar] = numLdloca.GetOrDefault(locVar) + direction;
-					} else {
-						throw new NotSupportedException(expr.Code.ToString());
-					}
-				}
-				foreach (ILExpression child in expr.Arguments)
-					AnalyzeNode(child, direction);
-			} else {
-				var catchBlock = node as ILTryCatchBlock.CatchBlock;
-				if (catchBlock != null && catchBlock.ExceptionVariable != null) {
-					numStloc[catchBlock.ExceptionVariable] = numStloc.GetOrDefault(catchBlock.ExceptionVariable) + direction;
-				}
-				
-				foreach (ILNode child in node.GetChildren())
-					AnalyzeNode(child, direction);
+			foreach (var block in function.Descendants.OfType<Block>()) {
+				InlineAllInBlock(block);
 			}
 		}
-		
-		public bool InlineAllVariables()
-		{
-			bool modified = false;
-			ILInlining i = new ILInlining(method);
-			foreach (ILBlock block in method.GetSelfAndChildrenRecursive<ILBlock>())
-				modified |= i.InlineAllInBlock(block);
-			return modified;
-		}
-		
-		public bool InlineAllInBlock(ILBlock block)
-		{
-			bool modified = false;
-			List<ILNode> body = block.Body;
-			if (block is ILTryCatchBlock.CatchBlock && body.Count > 1) {
-				ILVariable v = ((ILTryCatchBlock.CatchBlock)block).ExceptionVariable;
-				if (v != null && v.IsGenerated) {
-					if (numLdloca.GetOrDefault(v) == 0 && numStloc.GetOrDefault(v) == 1 && numLdloc.GetOrDefault(v) == 1) {
-						ILVariable v2;
-						ILExpression ldException;
-						if (body[0].Match(ILCode.Stloc, out v2, out ldException) && ldException.MatchLdloc(v)) {
-							body.RemoveAt(0);
-							((ILTryCatchBlock.CatchBlock)block).ExceptionVariable = v2;
-							modified = true;
-						}
-					}
-				}
-			}
-			for(int i = 0; i < body.Count - 1;) {
-				ILVariable locVar;
-				ILExpression expr;
-				if (body[i].Match(ILCode.Stloc, out locVar, out expr) && InlineOneIfPossible(block.Body, i, aggressive: false)) {
-					modified = true;
-					i = Math.Max(0, i - 1); // Go back one step
-				} else {
-					i++;
-				}
-			}
-			foreach(ILBasicBlock bb in body.OfType<ILBasicBlock>()) {
-				modified |= InlineAllInBasicBlock(bb);
-			}
-			return modified;
-		}
-		
-		public bool InlineAllInBasicBlock(ILBasicBlock bb)
+
+		public bool InlineAllInBlock(Block block)
 		{
 			bool modified = false;
-			List<ILNode> body = bb.Body;
-			for(int i = 0; i < body.Count;) {
-				ILVariable locVar;
-				ILExpression expr;
-				if (body[i].Match(ILCode.Stloc, out locVar, out expr) && InlineOneIfPossible(bb.Body, i, aggressive: false)) {
+			int i = 0;
+			while (i < block.Instructions.Count) {
+				if (InlineOneIfPossible(block, i, aggressive: false)) {
 					modified = true;
-					i = Math.Max(0, i - 1); // Go back one step
+					i = Math.Max(0, i - 1);
+					// Go back one step
 				} else {
 					i++;
 				}
@@ -144,19 +54,16 @@ namespace ICSharpCode.Decompiler.ILAst
 		}
 		
 		/// <summary>
-		/// Inlines instructions before pos into block.Body[pos].
+		/// Inlines instructions before pos into block.Instructions[pos].
 		/// </summary>
 		/// <returns>The number of instructions that were inlined.</returns>
-		public int InlineInto(List<ILNode> body, int pos, bool aggressive)
+		public int InlineInto(Block block, int pos, bool aggressive)
 		{
-			if (pos >= body.Count)
+			if (pos >= block.Instructions.Count)
 				return 0;
 			int count = 0;
 			while (--pos >= 0) {
-				ILExpression expr = body[pos] as ILExpression;
-				if (expr == null || expr.Code != ILCode.Stloc)
-					break;
-				if (InlineOneIfPossible(body, pos, aggressive))
+				if (InlineOneIfPossible(block, pos, aggressive))
 					count++;
 				else
 					break;
@@ -171,10 +78,10 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <remarks>
 		/// After the operation, pos will point to the new combined instruction.
 		/// </remarks>
-		public bool InlineIfPossible(List<ILNode> body, ref int pos)
+		public bool InlineIfPossible(Block block, ref int pos)
 		{
-			if (InlineOneIfPossible(body, pos, true)) {
-				pos -= InlineInto(body, pos, false);
+			if (InlineOneIfPossible(block, pos, true)) {
+				pos -= InlineInto(block, pos, false);
 				return true;
 			}
 			return false;
@@ -183,29 +90,30 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <summary>
 		/// Inlines the stloc instruction at block.Body[pos] into the next instruction, if possible.
 		/// </summary>
-		public bool InlineOneIfPossible(List<ILNode> body, int pos, bool aggressive)
+		public bool InlineOneIfPossible(Block block, int pos, bool aggressive)
 		{
-			ILVariable v;
-			ILExpression inlinedExpression;
-			if (body[pos].Match(ILCode.Stloc, out v, out inlinedExpression) && !v.IsPinned) {
-				if (InlineIfPossible(v, inlinedExpression, body.ElementAtOrDefault(pos+1), aggressive)) {
+			StLoc stloc = block.Instructions[pos] as StLoc;
+			if (stloc != null && stloc.Variable.Kind != VariableKind.PinnedLocal) {
+				ILVariable v = stloc.Variable;
+				if (InlineIfPossible(v, stloc.Value, block.Instructions.ElementAtOrDefault(pos+1), aggressive)) {
 					// Assign the ranges of the stloc instruction:
-					inlinedExpression.ILRanges.AddRange(((ILExpression)body[pos]).ILRanges);
+					stloc.Value.AddILRange(stloc.ILRange);
 					// Remove the stloc instruction:
-					body.RemoveAt(pos);
+					Debug.Assert(block.Instructions[pos] == stloc);
+					block.Instructions.RemoveAt(pos);
 					return true;
-				} else if (numLdloc.GetOrDefault(v) == 0 && numLdloca.GetOrDefault(v) == 0) {
+				} else if (v.LoadCount == 0 && v.AddressCount == 0) {
 					// The variable is never loaded
-					if (inlinedExpression.HasNoSideEffects()) {
-						// Remove completely
-						AnalyzeNode(body[pos], -1);
-						body.RemoveAt(pos);
+					if (SemanticHelper.IsPure(stloc.Value.Flags)) {
+						// Remove completely if the instruction has no effects
+						// (except for reading locals)
+						block.Instructions.RemoveAt(pos);
 						return true;
-					} else if (inlinedExpression.CanBeExpressionStatement() && v.IsGenerated) {
+					} else if (v.Kind == VariableKind.StackSlot) {
 						// Assign the ranges of the stloc instruction:
-						inlinedExpression.ILRanges.AddRange(((ILExpression)body[pos]).ILRanges);
+						stloc.Value.AddILRange(stloc.ILRange);
 						// Remove the stloc, but keep the inner expression
-						body[pos] = inlinedExpression;
+						stloc.ReplaceWith(stloc.Value);
 						return true;
 					}
 				}
@@ -216,46 +124,40 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <summary>
 		/// Inlines 'expr' into 'next', if possible.
 		/// </summary>
-		bool InlineIfPossible(ILVariable v, ILExpression inlinedExpression, ILNode next, bool aggressive)
+		bool InlineIfPossible(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, bool aggressive)
 		{
 			// ensure the variable is accessed only a single time
-			if (numStloc.GetOrDefault(v) != 1)
+			if (v.StoreCount != 1)
 				return false;
-			int ldloc = numLdloc.GetOrDefault(v);
-			if (ldloc > 1 || ldloc + numLdloca.GetOrDefault(v) != 1)
+			if (v.LoadCount > 1 || v.LoadCount + v.AddressCount != 1)
 				return false;
 			
-			if (next is ILCondition)
-				next = ((ILCondition)next).Condition;
-			else if (next is ILWhileLoop)
-				next = ((ILWhileLoop)next).Condition;
-			
-			ILExpression parent;
-			int pos;
-			if (FindLoadInNext(next as ILExpression, v, inlinedExpression, out parent, out pos) == true) {
-				if (ldloc == 0) {
-					if (!IsGeneratedValueTypeTemporary((ILExpression)next, parent, pos, v, inlinedExpression))
-						return false;
+			ILInstruction loadInst;
+			if (FindLoadInNext(next, v, inlinedExpression, out loadInst) == true) {
+				if (loadInst.OpCode == OpCode.LdLoca) {
+					//if (!IsGeneratedValueTypeTemporary((ILInstruction)next, loadInst, v, inlinedExpression))
+					return false;
 				} else {
-					if (!aggressive && !v.IsGenerated && !NonAggressiveInlineInto((ILExpression)next, parent, inlinedExpression))
+					Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
+					if (!aggressive && v.Kind != VariableKind.StackSlot && !NonAggressiveInlineInto(next, loadInst, inlinedExpression))
 						return false;
 				}
 				
 				// Assign the ranges of the ldloc instruction:
-				inlinedExpression.ILRanges.AddRange(parent.Arguments[pos].ILRanges);
+				inlinedExpression.AddILRange(loadInst.ILRange);
 				
-				if (ldloc == 0) {
-					// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof' so that the types
-					// comes out correctly
-					parent.Arguments[pos] = new ILExpression(ILCode.AddressOf, null, inlinedExpression);
+				if (loadInst.OpCode == OpCode.LdLoca) {
+					// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
+					// to preserve the semantics of the compiler-generated temporary
+					loadInst.ReplaceWith(new AddressOf(inlinedExpression));
 				} else {
-					parent.Arguments[pos] = inlinedExpression;
+					loadInst.ReplaceWith(inlinedExpression);
 				}
 				return true;
 			}
 			return false;
 		}
-
+		/*
 		/// <summary>
 		/// Is this a temporary variable generated by the C# compiler for instance method calls on value type values
 		/// </summary>
@@ -264,7 +166,7 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <param name="pos">Index of the load within 'parent'</param>
 		/// <param name="v">The variable being inlined.</param>
 		/// <param name="inlinedExpression">The expression being inlined</param>
-		bool IsGeneratedValueTypeTemporary(ILExpression next, ILExpression parent, int pos, ILVariable v, ILExpression inlinedExpression)
+		bool IsGeneratedValueTypeTemporary(ILInstruction next, ILInstruction parent, int pos, ILVariable v, ILInstruction inlinedExpression)
 		{
 			if (pos == 0 && v.Type != null && v.Type.IsValueType) {
 				// Inlining a value type variable is allowed only if the resulting code will maintain the semantics
@@ -317,7 +219,7 @@ namespace ICSharpCode.Decompiler.ILAst
 					case ILCode.Castclass:
 					case ILCode.Unbox_Any:
 						// These are valid, but might occur as part of a foreach loop variable.
-						ILExpression arg = inlinedExpression.Arguments[0];
+						ILInstruction arg = inlinedExpression.Arguments[0];
 						if (arg.Code == ILCode.CallGetter || arg.Code == ILCode.CallvirtGetter || arg.Code == ILCode.Call || arg.Code == ILCode.Callvirt) {
 							mr = (MethodReference)arg.Operand;
 							if (mr.Name == "get_Current" && mr.HasThis)
@@ -345,24 +247,28 @@ namespace ICSharpCode.Decompiler.ILAst
 			}
 			return false;
 		}
+		*/
 		
 		/// <summary>
 		/// Determines whether a variable should be inlined in non-aggressive mode, even though it is not a generated variable.
 		/// </summary>
 		/// <param name="next">The next top-level expression</param>
-		/// <param name="parent">The direct parent of the load within 'next'</param>
+		/// <param name="loadInst">The load within 'next'</param>
 		/// <param name="inlinedExpression">The expression being inlined</param>
-		bool NonAggressiveInlineInto(ILExpression next, ILExpression parent, ILExpression inlinedExpression)
+		bool NonAggressiveInlineInto(ILInstruction next, ILInstruction loadInst, ILInstruction inlinedExpression)
 		{
-			if (inlinedExpression.Code == ILCode.DefaultValue)
+			Debug.Assert(loadInst.IsDescendantOf(next));
+			
+			if (inlinedExpression.OpCode == OpCode.DefaultValue)
 				return true;
 			
-			switch (next.Code) {
-				case ILCode.Ret:
-				case ILCode.Brtrue:
+			var parent = loadInst.Parent;
+			switch (next.OpCode) {
+				case OpCode.Return:
+				case OpCode.IfInstruction:
 					return parent == next;
-				case ILCode.Switch:
-					return parent == next || (parent.Code == ILCode.Sub && parent == next.Arguments[0]);
+				case OpCode.SwitchInstruction:
+					return parent == next || (parent.OpCode == OpCode.Sub && parent.Parent == next);
 				default:
 					return false;
 			}
@@ -371,37 +277,32 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <summary>
 		/// Gets whether 'expressionBeingMoved' can be inlined into 'expr'.
 		/// </summary>
-		public bool CanInlineInto(ILExpression expr, ILVariable v, ILExpression expressionBeingMoved)
+		public bool CanInlineInto(ILInstruction expr, ILVariable v, ILInstruction expressionBeingMoved)
 		{
-			ILExpression parent;
-			int pos;
-			return FindLoadInNext(expr, v, expressionBeingMoved, out parent, out pos) == true;
+			ILInstruction loadInst;
+			return FindLoadInNext(expr, v, expressionBeingMoved, out loadInst) == true;
 		}
 		
 		/// <summary>
 		/// Finds the position to inline to.
 		/// </summary>
 		/// <returns>true = found; false = cannot continue search; null = not found</returns>
-		bool? FindLoadInNext(ILExpression expr, ILVariable v, ILExpression expressionBeingMoved, out ILExpression parent, out int pos)
+		bool? FindLoadInNext(ILInstruction expr, ILVariable v, ILInstruction expressionBeingMoved, out ILInstruction loadInst)
 		{
-			parent = null;
-			pos = 0;
+			loadInst = null;
 			if (expr == null)
 				return false;
-			for (int i = 0; i < expr.Arguments.Count; i++) {
-				// Stop when seeing an opcode that does not guarantee that its operands will be evaluated.
-				// Inlining in that case might result in the inlined expresion not being evaluted.
-				if (i == 1 && (expr.Code == ILCode.LogicAnd || expr.Code == ILCode.LogicOr || expr.Code == ILCode.TernaryOp || expr.Code == ILCode.NullCoalescing))
+			if (expr.MatchLdLoc(v) || expr.MatchLdLoca(v)) {
+				// Match found, we can inline
+				loadInst = expr;
+				return true;
+			}
+			foreach (var child in expr.Children) {
+				if (!child.SlotInfo.CanInlineInto)
 					return false;
 				
-				ILExpression arg = expr.Arguments[i];
-				
-				if ((arg.Code == ILCode.Ldloc || arg.Code == ILCode.Ldloca) && arg.Operand == v) {
-					parent = expr;
-					pos = i;
-					return true;
-				}
-				bool? r = FindLoadInNext(arg, v, expressionBeingMoved, out parent, out pos);
+				// Recursively try to find the load instruction
+				bool? r = FindLoadInNext(child, v, expressionBeingMoved, out loadInst);
 				if (r != null)
 					return r;
 			}
@@ -414,40 +315,25 @@ namespace ICSharpCode.Decompiler.ILAst
 		/// <summary>
 		/// Determines whether it is safe to move 'expressionBeingMoved' past 'expr'
 		/// </summary>
-		bool IsSafeForInlineOver(ILExpression expr, ILExpression expressionBeingMoved)
+		bool IsSafeForInlineOver(ILInstruction expr, ILInstruction expressionBeingMoved)
 		{
-			switch (expr.Code) {
-				case ILCode.Ldloc:
-					ILVariable loadedVar = (ILVariable)expr.Operand;
-					if (numLdloca.GetOrDefault(loadedVar) != 0) {
-						// abort, inlining is not possible
-						return false;
-					}
-					foreach (ILExpression potentialStore in expressionBeingMoved.GetSelfAndChildrenRecursive<ILExpression>()) {
-						if (potentialStore.Code == ILCode.Stloc && potentialStore.Operand == loadedVar)
-							return false;
-					}
-					// the expression is loading a non-forbidden variable
-					return true;
-				case ILCode.Ldloca:
-				case ILCode.Ldflda:
-				case ILCode.Ldsflda:
-				case ILCode.Ldelema:
-				case ILCode.AddressOf:
-				case ILCode.ValueOf:
-				case ILCode.NullableOf:
-					// address-loading instructions are safe if their arguments are safe
-					foreach (ILExpression arg in expr.Arguments) {
-						if (!IsSafeForInlineOver(arg, expressionBeingMoved))
+			ILVariable v;
+			if (expr.MatchLdLoc(out v) && v.AddressCount == 0) {
+				// MayReorder() only looks at flags, so it doesn't
+				// allow reordering 'stloc x y; ldloc v' to 'ldloc v; stloc x y'
+				
+				// We'll allow the reordering unless x==v
+				if (expressionBeingMoved.HasFlag(InstructionFlags.MayWriteLocals)) {
+					foreach (var stloc in expressionBeingMoved.Descendants.OfType<StLoc>()) {
+						if (stloc.Variable == v)
 							return false;
 					}
-					return true;
-				default:
-					// instructions with no side-effects are safe (except for Ldloc and Ldloca which are handled separately)
-					return expr.HasNoSideEffects();
+				}
+				return true;
 			}
+			return SemanticHelper.MayReorder(expressionBeingMoved.Flags, expr.Flags);
 		}
-		
+		/*
 		/// <summary>
 		/// Runs a very simple form of copy propagation.
 		/// Copy propagation is used in two cases:
@@ -461,7 +347,7 @@ namespace ICSharpCode.Decompiler.ILAst
 			foreach (ILBlock block in method.GetSelfAndChildrenRecursive<ILBlock>()) {
 				for (int i = 0; i < block.Body.Count; i++) {
 					ILVariable v;
-					ILExpression copiedExpr;
+					ILInstruction copiedExpr;
 					if (block.Body[i].Match(ILCode.Stloc, out v, out copiedExpr)
 					    && !v.IsParameter && numStloc.GetOrDefault(v) == 1 && numLdloca.GetOrDefault(v) == 0
 					    && CanPerformCopyPropagation(copiedExpr, v))
@@ -470,16 +356,16 @@ namespace ICSharpCode.Decompiler.ILAst
 						ILVariable[] uninlinedArgs = new ILVariable[copiedExpr.Arguments.Count];
 						for (int j = 0; j < uninlinedArgs.Length; j++) {
 							uninlinedArgs[j] = new ILVariable { IsGenerated = true, Name = v.Name + "_cp_" + j };
-							block.Body.Insert(i++, new ILExpression(ILCode.Stloc, uninlinedArgs[j], copiedExpr.Arguments[j]));
+							block.Body.Insert(i++, new ILInstruction(ILCode.Stloc, uninlinedArgs[j], copiedExpr.Arguments[j]));
 						}
 						
 						// perform copy propagation:
-						foreach (var expr in method.GetSelfAndChildrenRecursive<ILExpression>()) {
+						foreach (var expr in method.GetSelfAndChildrenRecursive<ILInstruction>()) {
 							if (expr.Code == ILCode.Ldloc && expr.Operand == v) {
 								expr.Code = copiedExpr.Code;
 								expr.Operand = copiedExpr.Operand;
 								for (int j = 0; j < uninlinedArgs.Length; j++) {
-									expr.Arguments.Add(new ILExpression(ILCode.Ldloc, uninlinedArgs[j]));
+									expr.Arguments.Add(new ILInstruction(ILCode.Ldloc, uninlinedArgs[j]));
 								}
 							}
 						}
@@ -496,7 +382,7 @@ namespace ICSharpCode.Decompiler.ILAst
 			}
 		}
 		
-		bool CanPerformCopyPropagation(ILExpression expr, ILVariable copyVariable)
+		bool CanPerformCopyPropagation(ILInstruction expr, ILVariable copyVariable)
 		{
 			switch (expr.Code) {
 				case ILCode.Ldloca:
@@ -519,6 +405,6 @@ namespace ICSharpCode.Decompiler.ILAst
 				default:
 					return false;
 			}
-		}
+		}*/
 	}
 }

ICSharpCode.Decompiler/IL/Transforms/OptimizingTransform.cs

@@ -49,7 +49,9 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					if (ret.ReturnValue != null && ret.ReturnValue.MatchLdLoc(out v)
 					    && v.IsSingleUse && block.Instructions[0].MatchStLoc(v, out inst))
 					{
-						ret.ReturnValue = block.Instructions[0];
+						inst.AddILRange(ret.ReturnValue.ILRange);
+						inst.AddILRange(block.Instructions[0].ILRange);
+						ret.ReturnValue = inst;
 						block.Instructions.RemoveAt(0);
 					}
 				}

ICSharpCode.Decompiler/IL/Transforms/TransformingVisitor.cs

@@ -225,10 +225,9 @@ namespace ICSharpCode.Decompiler.IL
 			// If the block has only one instruction, we can remove the block too
 			// (but only if this doesn't change the pop-order in the phase 1 evaluation of the parent block)
 			if (block.Instructions.Count == 0) {
-				if (!block.FinalInstruction.HasFlag(InstructionFlags.MayPeek | InstructionFlags.MayPop))
-					return block.FinalInstruction;
+				return block.FinalInstruction;
 			} else if (block.Instructions.Count == 1 && block.FinalInstruction.OpCode == OpCode.Nop) {
-				if (block.Instructions[0].ResultType == StackType.Void && !block.Instructions[0].HasFlag(InstructionFlags.MayPeek | InstructionFlags.MayPop))
+				if (block.Instructions[0].ResultType == StackType.Void)
 					return block.Instructions[0];
 			}
 			return block;

ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -108,6 +108,7 @@
     <Compile Include="TestCases\HelloWorld.cs" />
     <Compile Include="TestCases\PropertiesAndEvents.cs" />
     <Compile Include="TestCases\Switch.cs" />
+    <Compile Include="TestCases\ValueTypeCall.cs" />
     <Compile Include="TestRunner.cs" />
     <Compile Include="Util\LongSetTests.cs" />
     <Compile Include="CustomAttributes\CustomAttributeTests.cs" />

ICSharpCode.Decompiler/Tests/TestCases/ValueTypeCall.cs

@@ -0,0 +1,62 @@
+using System;
+
+namespace ValueTypeCall
+{
+	public struct MutValueType
+	{
+		public int val;
+		
+		public void Increment()
+		{
+			Console.WriteLine("Inc() called on {0}", val);
+			val++;
+		}
+	}
+	
+	public class Program
+	{
+		public static void Main()
+		{
+			MutValueType m = new MutValueType();
+			RefParameter(ref m);
+			ValueParameter(m);
+			Field();
+			Box();
+		}
+		
+		static void RefParameter(ref MutValueType m)
+		{
+			m.Increment();
+			m.Increment();
+		}
+		
+		static void ValueParameter(MutValueType m)
+		{
+			m.Increment();
+			m.Increment();
+		}
+		
+		static readonly MutValueType ReadonlyField = new MutValueType { val = 100 };
+		static MutValueType MutableField = new MutValueType { val = 200 };
+		
+		static void Field()
+		{
+			ReadonlyField.Increment();
+			ReadonlyField.Increment();
+			MutableField.Increment();
+			MutableField.Increment();
+			// Ensure that 'v' isn't incorrectly removed
+			// as a compiler-generated temporary
+			MutValueType v = MutableField;
+			v.Increment();
+			Console.WriteLine("Final value in MutableField: " + MutableField.val);
+		}
+		
+		static void Box()
+		{
+			object o = new MutValueType { val = 300 };
+			((MutValueType)o).Increment();
+			((MutValueType)o).Increment();
+		}
+	}
+}

ICSharpCode.Decompiler/Tests/TestRunner.cs

@@ -64,6 +64,12 @@ namespace ICSharpCode.Decompiler.Tests
 			TestCompileDecompileCompileOutputAll("Generics.cs");
 		}
 
+		[Test]
+		public void ValueTypeCall()
+		{
+			TestCompileDecompileCompileOutputAll("ValueTypeCall.cs");
+		}
+
 		void TestCompileDecompileCompileOutputAll(string testFileName)
 		{
 			TestCompileDecompileCompileOutput(testFileName, CompilerOptions.None);