Make assignment ILAst opcodes return the assigned value

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -234,9 +234,8 @@ namespace ICSharpCode.Decompiler.CSharp
 		
 		ConvertedExpression Assignment(ConvertedExpression left, ConvertedExpression right)
 		{
-			return new ConvertedExpression(
-				new AssignmentExpression(left.Expression, right.ConvertTo(left.Type, this)),
-				left.Type);
+			return new AssignmentExpression(left.Expression, right.ConvertTo(left.Type, this))
+				.WithTypeInfo(left.Type);
 		}
 		
 		protected internal override ConvertedExpression VisitAdd(Add inst)

ICSharpCode.Decompiler/CSharp/NRefactoryExtensions.cs

@@ -19,11 +19,17 @@
 using System;
 using ICSharpCode.NRefactory.CSharp;
 using ICSharpCode.NRefactory.PatternMatching;
+using ICSharpCode.NRefactory.TypeSystem;
 
 namespace ICSharpCode.Decompiler.CSharp
 {
 	static class NRefactoryExtensions
 	{
+		public static ConvertedExpression WithTypeInfo(this Expression expr, IType type)
+		{
+			return new ConvertedExpression(expr, type);
+		}
+		
 		public static T WithAnnotation<T>(this T node, object annotation) where T : AstNode
 		{
 			if (annotation != null)

ICSharpCode.Decompiler/CSharp/StatementBuilder.cs

@@ -150,7 +150,10 @@ namespace ICSharpCode.Decompiler.CSharp
 		{
 			BlockStatement blockStatement = new BlockStatement();
 			foreach (var block in container.Blocks) {
-				blockStatement.Add(new LabelStatement { Label = block.Label });
+				if (block.IncomingEdgeCount > 1 || block != container.EntryPoint) {
+					// If there are any incoming branches to this block, add a label:
+					blockStatement.Add(new LabelStatement { Label = block.Label });
+				}
 				foreach (var inst in block.Instructions) {
 					blockStatement.Add(Convert(inst));
 				}

ICSharpCode.Decompiler/IL/BlockBuilder.cs

@@ -69,6 +69,7 @@ namespace ICSharpCode.Decompiler.IL
 				}
 				
 				var variable = new ILVariable(VariableKind.Exception, eh.CatchType, handlerBlock.ILRange.Start);
+				variable.Name = "ex";
 				handlerBlock.EntryPoint.Instructions.Add(new LdLoc(variable));
 				
 				ILInstruction filter;

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -493,21 +493,21 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Starg_S:
 					return Starg(reader.ReadByte());
 				case ILOpCode.Stind_I1:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.SByte);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.SByte));
 				case ILOpCode.Stind_I2:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Int16);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Int16));
 				case ILOpCode.Stind_I4:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Int32);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Int32));
 				case ILOpCode.Stind_I8:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Int64);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Int64));
 				case ILOpCode.Stind_R4:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Single);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Single));
 				case ILOpCode.Stind_R8:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Double);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Double));
 				case ILOpCode.Stind_I:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.IntPtr);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.IntPtr));
 				case ILOpCode.Stind_Ref:
-					return new StObj(value: Pop(), target: Pop(), type: typeSystem.Object);
+					return new Void(new StObj(value: Pop(), target: Pop(), type: typeSystem.Object));
 				case ILOpCode.Stloc:
 					return Stloc(reader.ReadUInt16());
 				case ILOpCode.Stloc_S:
@@ -535,7 +535,7 @@ namespace ICSharpCode.Decompiler.IL
 					{
 						var type = (TypeReference)ReadAndDecodeMetadataToken();
 						var ld = new LdObj(Pop(), type);
-						return new StObj(Pop(), ld, type);
+						return new Void(new StObj(Pop(), ld, type));
 					}
 				case ILOpCode.Initobj:
 					return new InitObj(Pop(), (TypeReference)ReadAndDecodeMetadataToken());
@@ -561,7 +561,7 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Ldflda:
 					return new LdFlda(Pop(), (FieldReference)ReadAndDecodeMetadataToken());
 				case ILOpCode.Stfld:
-					return new StFld(value: Pop(), target: Pop(), field: (FieldReference)ReadAndDecodeMetadataToken());
+					return new Void(new StFld(value: Pop(), target: Pop(), field: (FieldReference)ReadAndDecodeMetadataToken()));
 				case ILOpCode.Ldlen:
 					return new LdLen(Pop());
 				case ILOpCode.Ldobj:
@@ -571,7 +571,7 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Ldsflda:
 					return new LdsFlda((FieldReference)ReadAndDecodeMetadataToken());
 				case ILOpCode.Stsfld:
-					return new StsFld(Pop(), (FieldReference)ReadAndDecodeMetadataToken());
+					return new Void(new StsFld(Pop(), (FieldReference)ReadAndDecodeMetadataToken()));
 				case ILOpCode.Ldtoken:
 					return new LdToken((MemberReference)ReadAndDecodeMetadataToken());
 				case ILOpCode.Ldvirtftn:
@@ -599,7 +599,7 @@ namespace ICSharpCode.Decompiler.IL
 				case ILOpCode.Stelem_Ref:
 					throw new NotImplementedException();
 				case ILOpCode.Stobj:
-					return new StObj(value: Pop(), target: Pop(), type: (TypeReference)ReadAndDecodeMetadataToken());
+					return new Void(new StObj(value: Pop(), target: Pop(), type: (TypeReference)ReadAndDecodeMetadataToken()));
 				case ILOpCode.Throw:
 					return new Throw(Pop());
 				case ILOpCode.Unbox:
@@ -648,7 +648,7 @@ namespace ICSharpCode.Decompiler.IL
 
 		private ILInstruction Starg(ushort v)
 		{
-			return new StLoc(Pop(), parameterVariables[v]);
+			return new Void(new StLoc(Pop(), parameterVariables[v]));
 		}
 
 		private ILInstruction Ldloc(ushort v)
@@ -663,7 +663,7 @@ namespace ICSharpCode.Decompiler.IL
 
 		private ILInstruction Stloc(ushort v)
 		{
-			return new StLoc(Pop(), localVariables[v]);
+			return new Void(new StLoc(Pop(), localVariables[v]));
 		}
 
 		private ILInstruction DecodeConstrainedCall()

ICSharpCode.Decompiler/IL/Instructions.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using Mono.Cecil;
 
 namespace ICSharpCode.Decompiler.IL
@@ -622,6 +623,7 @@ namespace ICSharpCode.Decompiler.IL
 		{
 			this.Filter = filter;
 			this.Body = body;
+			Debug.Assert(variable != null);
 			this.variable = variable;
 		}
 		ILInstruction filter;
@@ -825,6 +827,7 @@ namespace ICSharpCode.Decompiler.IL
 	{
 		public LdLoc(ILVariable variable) : base(OpCode.LdLoc)
 		{
+			Debug.Assert(variable != null);
 			this.variable = variable;
 		}
 		readonly ILVariable variable;
@@ -848,6 +851,7 @@ namespace ICSharpCode.Decompiler.IL
 	{
 		public LdLoca(ILVariable variable) : base(OpCode.LdLoca)
 		{
+			Debug.Assert(variable != null);
 			this.variable = variable;
 		}
 		public override StackType ResultType { get { return StackType.Ref; } }
@@ -872,6 +876,7 @@ namespace ICSharpCode.Decompiler.IL
 		public StLoc(ILInstruction value, ILVariable variable) : base(OpCode.StLoc)
 		{
 			this.Value = value;
+			Debug.Assert(variable != null);
 			this.variable = variable;
 		}
 		ILInstruction value;
@@ -896,10 +901,10 @@ namespace ICSharpCode.Decompiler.IL
 			this.Value = this.value.Inline(flagsBefore, instructionStack, out finished);
 			return this;
 		}
-		public override StackType ResultType { get { return StackType.Void; } }
 		readonly ILVariable variable;
 		/// <summary>Returns the variable operand.</summary>
 		public ILVariable Variable { get { return variable; } }
+		public override StackType ResultType { get { return variable.Type.GetStackType(); } }
 		protected override InstructionFlags ComputeFlags()
 		{
 			return value.Flags;
@@ -1306,10 +1311,10 @@ namespace ICSharpCode.Decompiler.IL
 		public bool IsVolatile { get; set; }
 		/// <summary>Returns the alignment specified by the 'unaligned' prefix; or 0 if there was no 'unaligned' prefix.</summary>
 		public byte UnalignedPrefix { get; set; }
-		public override StackType ResultType { get { return StackType.Void; } }
 		readonly FieldReference field;
 		/// <summary>Returns the field operand.</summary>
 		public FieldReference Field { get { return field; } }
+		public override StackType ResultType { get { return field.FieldType.GetStackType(); } }
 		protected override InstructionFlags ComputeFlags()
 		{
 			return target.Flags | value.Flags | InstructionFlags.SideEffect | InstructionFlags.MayThrow;
@@ -1427,10 +1432,10 @@ namespace ICSharpCode.Decompiler.IL
 		public bool IsVolatile { get; set; }
 		/// <summary>Returns the alignment specified by the 'unaligned' prefix; or 0 if there was no 'unaligned' prefix.</summary>
 		public byte UnalignedPrefix { get; set; }
-		public override StackType ResultType { get { return StackType.Void; } }
 		readonly FieldReference field;
 		/// <summary>Returns the field operand.</summary>
 		public FieldReference Field { get { return field; } }
+		public override StackType ResultType { get { return field.FieldType.GetStackType(); } }
 		protected override InstructionFlags ComputeFlags()
 		{
 			return value.Flags | InstructionFlags.SideEffect;

ICSharpCode.Decompiler/IL/Instructions.tt

@@ -106,7 +106,8 @@
 		new OpCode("ldloca", "Loads the address of a local variable. (ldarga/ldloca)",
 			CustomClassName("LdLoca"), NoArguments, ResultType("Ref"), HasVariableOperand),
 		new OpCode("stloc", "Stores a value into a local variable. (starg/stloc)",
-			CustomClassName("StLoc"), CustomArguments("value"), VoidResult, HasVariableOperand),
+			CustomClassName("StLoc"), CustomArguments("value"), HasVariableOperand,
+			ResultType("variable.Type.GetStackType()")),
 		new OpCode("ldstr", "Loads a constant string.",
 			CustomClassName("LdStr"), LoadConstant("string"), ResultType("O")),
 		new OpCode("ldc.i4", "Loads a constant 32-bit integer.",
@@ -136,14 +137,18 @@
 		new OpCode("ldflda", "Load address of instance field",
 			CustomClassName("LdFlda"), CustomArguments("target"), MayThrow, HasFieldOperand, ResultType("Ref")),
 		new OpCode("stfld", "Store value to instance field",
-			CustomClassName("StFld"), CustomArguments("target", "value"), MemoryAccess, SupportsVolatilePrefix, SupportsUnalignedPrefix, MayThrow, VoidResult, HasFieldOperand),
+			CustomClassName("StFld"), CustomArguments("target", "value"),
+			MemoryAccess, SupportsVolatilePrefix, SupportsUnalignedPrefix, MayThrow, HasFieldOperand,
+			ResultType("field.FieldType.GetStackType()")),
 		new OpCode("ldsfld", "Load static field",
 			CustomClassName("LdsFld"), NoArguments, MemoryAccess, SupportsVolatilePrefix, SupportsUnalignedPrefix,
 			HasFieldOperand, ResultType("field.FieldType.GetStackType()")),
 		new OpCode("ldsflda", "Load static field address",
 			CustomClassName("LdsFlda"), NoArguments, ResultType("Ref"), HasFieldOperand),
 		new OpCode("stsfld", "Store value to static field",
-			CustomClassName("StsFld"), CustomArguments("value"), MemoryAccess, SupportsVolatilePrefix, SupportsUnalignedPrefix, VoidResult, HasFieldOperand),
+			CustomClassName("StsFld"), CustomArguments("value"),
+			MemoryAccess, SupportsVolatilePrefix, SupportsUnalignedPrefix, HasFieldOperand,
+			ResultType("field.FieldType.GetStackType()")),
 
 		new OpCode("castclass", "Casts an object to a class.",
 			CustomClassName("CastClass"), Unary, HasTypeOperand, MayThrow, ResultType("type.GetStackType()")),
@@ -186,6 +191,7 @@
 #>
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using Mono.Cecil;
 
 namespace ICSharpCode.Decompiler.IL
@@ -635,6 +641,7 @@ namespace ICSharpCode.Decompiler.IL
 	static Action<OpCode> HasVariableOperand = opCode => {
 		opCode.ConstructorParameters.Add("ILVariable variable");
 		opCode.Members.Add("readonly ILVariable variable;");
+		opCode.ConstructorBody.Add("Debug.Assert(variable != null);");
 		opCode.ConstructorBody.Add("this.variable = variable;");
 		opCode.Members.Add("/// <summary>Returns the variable operand.</summary>" + Environment.NewLine
 						+ "public ILVariable Variable { get { return variable; } }");

ICSharpCode.Decompiler/IL/Instructions/Branch.cs

@@ -90,9 +90,9 @@ namespace ICSharpCode.Decompiler.IL
 			output.Write(' ');
 			output.WriteReference(TargetLabel, (object)targetBlock ?? TargetILOffset, isLocal: true);
 			if (PopCount != 0) {
-				output.Write(" (pop ");
+				output.Write(" (pops ");
 				output.Write(PopCount.ToString());
-				output.Write(')');
+				output.Write(" element)");
 			}
 		}
 	}

ICSharpCode.Decompiler/IL/Instructions/ILInstruction.cs

@@ -46,10 +46,11 @@ namespace ICSharpCode.Decompiler.IL
 				throw new ArgumentException("Argument must not be of type void", "inst");
 		}
 		
-		internal static void ValidateChild(ILInstruction inst)
+		internal void ValidateChild(ILInstruction inst)
 		{
 			if (inst == null)
 				throw new ArgumentNullException("inst");
+			Debug.Assert(!this.IsDescendantOf(inst), "ILAst must form a tree");
 		}
 		
 		[Conditional("DEBUG")]

ICSharpCode.Decompiler/IL/TransformingVisitor.cs

@@ -79,9 +79,12 @@ namespace ICSharpCode.Decompiler.IL
 						// Wrap the instruction on top of the stack into an inline block,
 						// and append our void-typed instruction to the end of that block.
 						var headInst = stack.Pop();
-						var nestedBlock = headInst as Block ?? new Block { Instructions = { headInst } };
+						var nestedBlock = headInst as Block ?? new Block {
+							Instructions = { headInst },
+							ILRange = headInst.ILRange
+						};
 						nestedBlock.Instructions.Add(inst);
-						stack.Push(block);
+						stack.Push(nestedBlock);
 					} else {
 						// We can't move incomplete instructions into a nested block
 						// or the instruction stack was empty