예제 #1
0
        protected override bool EmitInternal(BinaryExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            Expression left = node.Left;
            Expression right = node.Right;
            Type       leftType, rightType;

            context.EmitLoadArgument(left, false, out leftType);
            context.EmitLoadArgument(right, false, out rightType);
            context.EmitArithmeticOperation(node.NodeType, node.Type, leftType, rightType, node.Method);
            resultType = node.Type;
            return(false);
        }
        protected override bool EmitInternal(UnaryExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            if (node.Type != typeof(bool) && node.Type != typeof(bool?))
            {
                return(ExpressionEmittersCollection.Emit(Expression.OnesComplement(node.Operand, node.Method), context, returnDefaultValueLabel, whatReturn, extend, out resultType));
            }
            GroboIL il = context.Il;

            if (node.Method != null)
            {
                throw new NotSupportedException("Custom operator '" + node.NodeType + "' is not supported");
            }
            var operand = node.Operand;

            context.EmitLoadArgument(operand, false, out resultType);
            if (resultType == typeof(bool))
            {
                il.Ldc_I4(1);
                il.Xor();
            }
            else if (resultType == typeof(bool?))
            {
                using (var value = context.DeclareLocal(typeof(bool?)))
                {
                    il.Stloc(value);
                    il.Ldloca(value);
                    context.EmitHasValueAccess(typeof(bool?));
                    var returnLabel = il.DefineLabel("return");
                    il.Brfalse(returnLabel);
                    il.Ldloca(value);
                    context.EmitValueAccess(typeof(bool?));
                    il.Ldc_I4(1);
                    il.Xor();
                    il.Newobj(nullableBoolConstructor);
                    il.Stloc(value);
                    context.MarkLabelAndSurroundWithSP(returnLabel);
                    il.Ldloc(value);
                }
            }
            else
            {
                throw new InvalidOperationException("Cannot perform '" + node.NodeType + "' operator on type '" + resultType + "'");
            }
            return(false);
        }
        protected override bool EmitInternal(BinaryExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            var  left = node.Left;
            var  right = node.Right;
            Type leftType, rightType;

            context.EmitLoadArgument(left, false, out leftType);
            context.EmitLoadArgument(right, false, out rightType);
            var il = context.Il;

            if (node.Method != null)
            {
                if (!leftType.IsNullable() && !rightType.IsNullable())
                {
                    il.Call(node.Method);
                }
                else
                {
                    using (var localLeft = context.DeclareLocal(leftType))
                        using (var localRight = context.DeclareLocal(rightType))
                        {
                            il.Stloc(localRight);
                            il.Stloc(localLeft);
                            var returnNullLabel = il.DefineLabel("returnNull");
                            if (leftType.IsNullable())
                            {
                                il.Ldloca(localLeft);
                                context.EmitHasValueAccess(leftType);
                                il.Brfalse(returnNullLabel);
                            }
                            if (rightType.IsNullable())
                            {
                                il.Ldloca(localRight);
                                context.EmitHasValueAccess(rightType);
                                il.Brfalse(returnNullLabel);
                            }
                            if (!leftType.IsNullable())
                            {
                                il.Ldloc(localLeft);
                            }
                            else
                            {
                                il.Ldloca(localLeft);
                                context.EmitValueAccess(leftType);
                            }
                            if (!rightType.IsNullable())
                            {
                                il.Ldloc(localRight);
                            }
                            else
                            {
                                il.Ldloca(localRight);
                                context.EmitValueAccess(rightType);
                            }
                            il.Call(node.Method);

                            var doneLabel = il.DefineLabel("done");
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(returnNullLabel);
                            context.EmitLoadDefaultValue(node.Type);
                            context.MarkLabelAndSurroundWithSP(doneLabel);
                        }
                }
                resultType = node.Method.ReturnType;
            }
            else
            {
                var type = leftType;
                if (type != rightType)
                {
                    throw new InvalidOperationException("Cannot compare objects of different types '" + leftType + "' and '" + rightType + "'");
                }
                if (!type.IsNullable())
                {
                    switch (node.NodeType)
                    {
                    case ExpressionType.GreaterThan:
                        il.Cgt(type.Unsigned());
                        break;

                    case ExpressionType.LessThan:
                        il.Clt(type.Unsigned());
                        break;

                    case ExpressionType.GreaterThanOrEqual:
                        il.Clt(type.Unsigned());
                        il.Ldc_I4(1);
                        il.Xor();
                        break;

                    case ExpressionType.LessThanOrEqual:
                        il.Cgt(type.Unsigned());
                        il.Ldc_I4(1);
                        il.Xor();
                        break;

                    default:
                        throw new InvalidOperationException();
                    }
                    resultType = typeof(bool);
                }
                else
                {
                    if (!context.Options.HasFlag(CompilerOptions.UseTernaryLogic))
                    {
                        using (var localLeft = context.DeclareLocal(type))
                            using (var localRight = context.DeclareLocal(type))
                            {
                                il.Stloc(localRight);
                                il.Stloc(localLeft);
                                il.Ldloca(localLeft);
                                context.EmitValueAccess(type);
                                il.Ldloca(localRight);
                                context.EmitValueAccess(type);
                                var returnFalseLabel = il.DefineLabel("returnFalse");

                                var argument = type.GetGenericArguments()[0];
                                switch (node.NodeType)
                                {
                                case ExpressionType.GreaterThan:
                                    il.Ble(returnFalseLabel, argument.Unsigned());
                                    break;

                                case ExpressionType.LessThan:
                                    il.Bge(returnFalseLabel, argument.Unsigned());
                                    break;

                                case ExpressionType.GreaterThanOrEqual:
                                    il.Blt(returnFalseLabel, argument.Unsigned());
                                    break;

                                case ExpressionType.LessThanOrEqual:
                                    il.Bgt(returnFalseLabel, argument.Unsigned());
                                    break;

                                default:
                                    throw new InvalidOperationException();
                                }
                                il.Ldloca(localLeft);
                                context.EmitHasValueAccess(type);
                                il.Ldloca(localRight);
                                context.EmitHasValueAccess(type);
                                il.And();
                                var doneLabel = il.DefineLabel("done");
                                il.Br(doneLabel);
                                context.MarkLabelAndSurroundWithSP(returnFalseLabel);
                                il.Ldc_I4(0);
                                context.MarkLabelAndSurroundWithSP(doneLabel);
                                resultType = typeof(bool);
                            }
                    }
                    else
                    {
                        using (var localLeft = context.DeclareLocal(type))
                            using (var localRight = context.DeclareLocal(type))
                            {
                                il.Stloc(localRight);
                                il.Stloc(localLeft);
                                il.Ldloca(localLeft);
                                context.EmitHasValueAccess(type);
                                il.Ldloca(localRight);
                                context.EmitHasValueAccess(type);
                                il.And();
                                var returnNullLabel = il.DefineLabel("returnNull");
                                il.Brfalse(returnNullLabel);
                                il.Ldloca(localLeft);
                                context.EmitValueAccess(type);
                                il.Ldloca(localRight);
                                context.EmitValueAccess(type);
                                var argumentType = type.GetGenericArguments()[0];

                                switch (node.NodeType)
                                {
                                case ExpressionType.GreaterThan:
                                    il.Cgt(argumentType.Unsigned());
                                    break;

                                case ExpressionType.LessThan:
                                    il.Clt(argumentType.Unsigned());
                                    break;

                                case ExpressionType.GreaterThanOrEqual:
                                    il.Clt(argumentType.Unsigned());
                                    il.Ldc_I4(1);
                                    il.Xor();
                                    break;

                                case ExpressionType.LessThanOrEqual:
                                    il.Cgt(argumentType.Unsigned());
                                    il.Ldc_I4(1);
                                    il.Xor();
                                    break;

                                default:
                                    throw new InvalidOperationException();
                                }
                                il.Newobj(nullableBoolConstructor);

                                var doneLabel = il.DefineLabel("done");
                                il.Br(doneLabel);
                                context.MarkLabelAndSurroundWithSP(returnNullLabel);
                                context.EmitLoadDefaultValue(typeof(bool?));
                                context.MarkLabelAndSurroundWithSP(doneLabel);
                                resultType = typeof(bool?);
                            }
                    }
                }
            }
            return(false);
        }
예제 #4
0
        protected override bool EmitInternal(MethodCallExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            var        result = false;
            GroboIL    il     = context.Il;
            var        method = node.Method;
            Expression obj;
            IEnumerable <Expression>    arguments;
            IEnumerable <ParameterInfo> parameters;
            bool isStatic = method.IsStatic;

            if (!isStatic)
            {
                obj        = node.Object;
                arguments  = node.Arguments;
                parameters = method.GetParameters();
            }
            else if (method.DeclaringType == typeof(Enumerable))
            {
                obj        = node.Arguments[0];
                arguments  = node.Arguments.Skip(1);
                parameters = method.GetParameters().Skip(1);
            }
            else
            {
                obj        = null;
                arguments  = node.Arguments;
                parameters = method.GetParameters();
            }
            Type type = obj == null ? null : obj.Type;

            if (obj != null)
            {
                Type actualType;
                result |= ExpressionEmittersCollection.Emit(obj, context, returnDefaultValueLabel, isStatic ? ResultType.Value : ResultType.ByRefValueTypesOnly, extend, out actualType); // stack: [obj]
                if (actualType == typeof(void))
                {
                    throw new InvalidOperationException("Unable to call method on void");
                }
                if (actualType.IsValueType && !isStatic)
                {
                    using (var temp = context.DeclareLocal(actualType))
                    {
                        il.Stloc(temp);
                        il.Ldloca(temp);
                    }
                    actualType = actualType.MakeByRefType();
                }
                if (context.Options.HasFlag(CompilerOptions.CheckNullReferences) && !actualType.IsValueType)
                {
                    if (method.DeclaringType != typeof(Enumerable))
                    {
                        result |= context.EmitNullChecking(type, returnDefaultValueLabel);
                    }
                    else
                    {
                        var arrIsNotNullLabel = il.DefineLabel("arrIsNotNull");
                        il.Dup();
                        il.Brtrue(arrIsNotNullLabel);
                        il.Pop();
                        il.Ldc_I4(0);
                        il.Newarr(GetElementType(type));
                        context.MarkLabelAndSurroundWithSP(arrIsNotNullLabel);
                    }
                }
            }

            var parametersArray = parameters.ToArray();
            var argumentsArray  = arguments.ToArray();

            for (int i = 0; i < argumentsArray.Length; i++)
            {
                var argument  = argumentsArray[i];
                var parameter = parametersArray[i];
                if (parameter.ParameterType.IsByRef)
                {
                    Type argumentType;
                    var  options = context.Options;
                    context.Options = CompilerOptions.None;
                    ExpressionEmittersCollection.Emit(argument, context, null, ResultType.ByRefAll, false, out argumentType);
                    context.Options = options;
                    if (!argumentType.IsByRef)
                    {
                        throw new InvalidOperationException("Expected type by reference");
                    }
                }
                else
                {
                    Type argumentType;
                    context.EmitLoadArgument(argument, true, out argumentType);
                }
            }
            il.Call(method, type);
            resultType = node.Type;
            return(result);
        }
        protected override bool EmitInternal(BinaryExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            Expression left = node.Left;
            Expression right = node.Right;
            Type       leftType, rightType;

            context.EmitLoadArgument(left, false, out leftType);
            context.EmitLoadArgument(right, false, out rightType);
            GroboIL il = context.Il;

            if (!leftType.IsNullable() && !rightType.IsNullable())
            {
                if (node.Method != null)
                {
                    il.Call(node.Method);
                }
                else
                {
                    if (leftType.IsStruct() || rightType.IsStruct())
                    {
                        throw new InvalidOperationException("Cannot compare structs");
                    }
                    il.Ceq();
                    if (node.NodeType == ExpressionType.NotEqual)
                    {
                        il.Ldc_I4(1);
                        il.Xor();
                    }
                }
            }
            else
            {
                var type = leftType;
                if (type != rightType)
                {
                    throw new InvalidOperationException("Cannot compare objects of different types '" + leftType + "' and '" + rightType + "'");
                }
                using (var localLeft = context.DeclareLocal(type))
                    using (var localRight = context.DeclareLocal(type))
                    {
                        il.Stloc(localRight);
                        il.Stloc(localLeft);
                        if (node.Method != null)
                        {
                            il.Ldloca(localLeft);             // stack: [&left]
                            context.EmitHasValueAccess(type); // stack: [left.HasValue]
                            il.Dup();                         // stack: [left.HasValue, left.HasValue]
                            il.Ldloca(localRight);            // stack: [left.HasValue, left.HasValue, &right]
                            context.EmitHasValueAccess(type); // stack: [left.HasValue, left.HasValue, right.HasValue]
                            var notEqualLabel = il.DefineLabel("notEqual");
                            il.Bne_Un(notEqualLabel);         // stack: [left.HasValue]
                            var equalLabel = il.DefineLabel("equal");
                            il.Brfalse(equalLabel);
                            il.Ldloca(localLeft);
                            context.EmitValueAccess(type);
                            il.Ldloca(localRight);
                            context.EmitValueAccess(type);
                            il.Call(node.Method);
                            var doneLabel = il.DefineLabel("done");
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(notEqualLabel);
                            il.Pop();
                            il.Ldc_I4(node.NodeType == ExpressionType.Equal ? 0 : 1);
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(equalLabel);
                            il.Ldc_I4(node.NodeType == ExpressionType.Equal ? 1 : 0);
                            context.MarkLabelAndSurroundWithSP(doneLabel);
                        }
                        else
                        {
                            il.Ldloca(localLeft);
                            context.EmitValueAccess(type);
                            il.Ldloca(localRight);
                            context.EmitValueAccess(type);
                            var notEqualLabel = il.DefineLabel("notEqual");
                            il.Bne_Un(notEqualLabel);
                            il.Ldloca(localLeft);
                            context.EmitHasValueAccess(type);
                            il.Ldloca(localRight);
                            context.EmitHasValueAccess(type);
                            il.Ceq();
                            var doneLabel = il.DefineLabel("done");
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(notEqualLabel);
                            il.Ldc_I4(0);
                            context.MarkLabelAndSurroundWithSP(doneLabel);
                            if (node.NodeType == ExpressionType.NotEqual)
                            {
                                il.Ldc_I4(1);
                                il.Xor();
                            }
                        }
                    }
            }
            resultType = typeof(bool);
            return(false);
        }
        protected override bool EmitInternal(BinaryExpression node, EmittingContext context, GroboIL.Label returnDefaultValueLabel, ResultType whatReturn, bool extend, out Type resultType)
        {
            GroboIL il = context.Il;

            if (node.Method != null)
            {
                throw new NotSupportedException("Custom operator '" + node.NodeType + "' is not supported");
            }
            Expression left  = node.Left;
            Expression right = node.Right;
            Type       leftType;

            context.EmitLoadArgument(left, false, out leftType); // stack: [left]
            if (leftType == typeof(bool))
            {
                switch (node.NodeType)
                {
                case ExpressionType.AndAlso:
                {
                    var returnFalseLabel = il.DefineLabel("returnFalse");
                    il.Brfalse(returnFalseLabel);                          // if(left == false) return false; stack: []
                    Type rightType;
                    context.EmitLoadArgument(right, false, out rightType); // stack: [right]
                    var doneLabel = il.DefineLabel("done");
                    il.Br(doneLabel);                                      // goto done; stack: [right]
                    context.MarkLabelAndSurroundWithSP(returnFalseLabel);
                    il.Ldc_I4(0);                                          // stack: [false]
                    if (rightType == typeof(bool?))
                    {
                        il.Newobj(nullableBoolConstructor);     // stack: [new bool?(false)]
                    }
                    context.MarkLabelAndSurroundWithSP(doneLabel);
                    resultType = rightType;
                    break;
                }

                case ExpressionType.OrElse:
                {
                    var returnTrueLabel = il.DefineLabel("returnTrue");
                    il.Brtrue(returnTrueLabel);                            // if(left == true) return true; stack: []
                    Type rightType;
                    context.EmitLoadArgument(right, false, out rightType); // stack: [right]
                    var doneLabel = il.DefineLabel("done");
                    il.Br(doneLabel);                                      // goto done; stack: [right]
                    context.MarkLabelAndSurroundWithSP(returnTrueLabel);
                    il.Ldc_I4(1);                                          // stack: [true]
                    if (rightType == typeof(bool?))
                    {
                        il.Newobj(nullableBoolConstructor);     // stack: [new bool?(true)]
                    }
                    context.MarkLabelAndSurroundWithSP(doneLabel);
                    resultType = rightType;
                    break;
                }

                default:
                    throw new NotSupportedException("Node type '" + node.NodeType + "' is not supported");
                }
            }
            else // bool?
            {
                switch (node.NodeType)
                {
                case ExpressionType.AndAlso:
                {
                    /*
                     * +-------+-------+-------+-------+
                     * |  &&   | null  | false | true  |
                     * +-------+-------+-------+-------+
                     * | null  | null  | false | null  |
                     * +-------+-------+-------+-------+
                     * | false | false | false | false |
                     * +-------+-------+-------+-------+
                     * | true  | null  | false | true  |
                     * +-------+-------+-------+-------+
                     */
                    using (var localLeft = context.DeclareLocal(typeof(bool?)))
                    {
                        il.Stloc(localLeft);                                   // localLeft = left; stack: []
                        il.Ldloca(localLeft);                                  // stack: [&localLeft]
                        context.EmitHasValueAccess(typeof(bool?));             // stack: [localLeft.HasValue]
                        il.Ldc_I4(1);                                          // stack: [localLeft.HasValue, true]
                        il.Xor();                                              // stack: [!localLeft.HasValue]
                        il.Ldloca(localLeft);                                  // stack: [!localLeft.HasValue, &localLeft]
                        context.EmitValueAccess(typeof(bool?));                // stack: [!localLeft.HasValue, localLeft.Value]
                        il.Or();                                               // stack: [!localLeft.HasValue || localLeft.Value]
                        var returnFalseLabel = il.DefineLabel("returnFalse");
                        il.Brfalse(returnFalseLabel);                          // if(localLeft == false) goto returnFalse; stack: []
                        Type rightType;
                        context.EmitLoadArgument(right, false, out rightType); // stack: [right]
                        using (var localRight = context.DeclareLocal(rightType))
                        {
                            il.Stloc(localRight);     // localRight = right; stack: []
                            if (rightType == typeof(bool))
                            {
                                il.Ldloc(localRight);     // stack: [localRight]
                            }
                            else
                            {
                                il.Ldloca(localRight);                     // stack: [&localRight]
                                context.EmitHasValueAccess(typeof(bool?)); // stack: [localRight.HasValue]
                                il.Ldc_I4(1);                              // stack: [localRight.HasValue, true]
                                il.Xor();                                  // stack: [!localRight.HasValue]
                                il.Ldloca(localRight);                     // stack: [!localRight.HasValue, &localRight]
                                context.EmitValueAccess(typeof(bool?));    // stack: [!localRight.HasValue, localRight.Value]
                                il.Or();                                   // stack: [!localRight.HasValue || localRight.Value]
                            }
                            il.Brfalse(returnFalseLabel);                  // if(localRight == false) goto returnFalse;
                            if (rightType == typeof(bool))
                            {
                                il.Ldloc(localRight);     // stack: [localRight]
                            }
                            else
                            {
                                il.Ldloca(localRight);                     // stack: [&localRight]
                                context.EmitHasValueAccess(typeof(bool?)); // stack: [localRight.HasValue]
                                il.Ldloca(localRight);                     // stack: [localRight.HasValue, &localRight]
                                context.EmitValueAccess(typeof(bool?));    // stack: [localRight.HasValue, localRight.Value]
                                il.And();                                  // stack: [localRight.HasValue && localRight.Value]
                            }
                            var returnLeftLabel = il.DefineLabel("returnLeft");
                            il.Brtrue(returnLeftLabel); // if(localRight == true) goto returnLeft;
                            il.Ldloca(localLeft);       // stack: [&localLeft]
                            il.Initobj(typeof(bool?));  // localLeft = default(bool?); stack: []
                            context.MarkLabelAndSurroundWithSP(returnLeftLabel);
                            il.Ldloc(localLeft);        // stack: [localLeft]
                            var doneLabel = il.DefineLabel("done");
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(returnFalseLabel);
                            il.Ldc_I4(0);                       // stack: [false]
                            il.Newobj(nullableBoolConstructor); // new bool?(false)
                            context.MarkLabelAndSurroundWithSP(doneLabel);
                            resultType = typeof(bool?);
                        }
                    }
                    break;
                }

                case ExpressionType.OrElse:
                {
                    /*
                     * +-------+-------+-------+-------+
                     * |  ||   | null  | false | true  |
                     * +-------+-------+-------+-------+
                     * | null  | null  | null  | true  |
                     * +-------+-------+-------+-------+
                     * | false | null  | false | true  |
                     * +-------+-------+-------+-------+
                     * | true  | true  | true  | true  |
                     * +-------+-------+-------+-------+
                     */
                    using (var localLeft = context.DeclareLocal(typeof(bool?)))
                    {
                        il.Stloc(localLeft);                                   // localLeft = left; stack: []
                        il.Ldloca(localLeft);                                  // stack: [&localLeft]
                        context.EmitHasValueAccess(typeof(bool?));             // stack: [localLeft.HasValue]
                        il.Ldloca(localLeft);                                  // stack: [localLeft.HasValue, &localLeft]
                        context.EmitValueAccess(typeof(bool?));                // stack: [localLeft.HasValue, localLeft.Value]
                        il.And();                                              // stack: [localLeft.HasValue && localLeft.Value]
                        var returnTrueLabel = il.DefineLabel("returnTrue");
                        il.Brtrue(returnTrueLabel);                            // if(localLeft == true) goto returnTrue; stack: []
                        Type rightType;
                        context.EmitLoadArgument(right, false, out rightType); // stack: [right]
                        using (var localRight = context.DeclareLocal(rightType))
                        {
                            il.Stloc(localRight);     // localRight = right; stack: []
                            if (rightType == typeof(bool))
                            {
                                il.Ldloc(localRight);     // stack: [localRight]
                            }
                            else
                            {
                                il.Ldloca(localRight);                     // stack: [&localRight]
                                context.EmitHasValueAccess(typeof(bool?)); // stack: [localRight.HasValue]
                                il.Ldloca(localRight);                     // stack: [localRight.HasValue, &localRight]
                                context.EmitValueAccess(typeof(bool?));    // stack: [localRight.HasValue, localRight.Value]
                                il.And();                                  // stack: [localRight.HasValue && localRight.Value]
                            }
                            il.Brtrue(returnTrueLabel);                    // if(localRight == true) goto returnTrue; stack: []
                            if (rightType == typeof(bool))
                            {
                                il.Ldloc(localRight);     // stack: [localRight]
                            }
                            else
                            {
                                il.Ldloca(localRight);                     // stack: [&localRight]
                                context.EmitHasValueAccess(typeof(bool?)); // stack: [localRight.HasValue]
                                il.Ldc_I4(1);                              // stack: [localRight.HasValue, true]
                                il.Xor();                                  // stack: [!localRight.HasValue]
                                il.Ldloca(localRight);                     // stack: [!localRight.HasValue, &localRight]
                                context.EmitValueAccess(typeof(bool?));    // stack: [!localRight.HasValue, localRight.Value]
                                il.Or();                                   // stack: [!localRight.HasValue || localRight.Value]
                            }
                            var returnLeftLabel = il.DefineLabel("returnLeft");
                            il.Brfalse(returnLeftLabel); // if(localRight == false) goto returnLeft;
                            il.Ldloca(localLeft);        // stack: [&localLeft]
                            il.Initobj(typeof(bool?));   // localLeft = default(bool?); stack: []
                            context.MarkLabelAndSurroundWithSP(returnLeftLabel);
                            il.Ldloc(localLeft);         // stack: [localLeft]
                            var doneLabel = il.DefineLabel("done");
                            il.Br(doneLabel);
                            context.MarkLabelAndSurroundWithSP(returnTrueLabel);
                            il.Ldc_I4(1);                       // stack: [true]
                            il.Newobj(nullableBoolConstructor); // new bool?(true)
                            context.MarkLabelAndSurroundWithSP(doneLabel);
                            resultType = typeof(bool?);
                        }
                    }
                    break;
                }

                default:
                    throw new NotSupportedException("Node type '" + node.NodeType + "' is not supported");
                }
            }
            return(false);
        }