C# ILGenerator.Subtract方法代码示例

        /// <summary>
        /// Generates CIL for the expression.
        /// </summary>
        /// <param name="generator"> The generator to output the CIL to. </param>
        /// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
        public override void GenerateCode(ILGenerator generator, OptimizationInfo optimizationInfo)
        {
            // If a return value is not expected, generate only the side-effects.
            /*if (optimizationInfo.SuppressReturnValue == true)
            {
                this.GenerateSideEffects(generator, optimizationInfo);
                return;
            }*/

            // Special case the addition operator.
            if (this.OperatorType == OperatorType.Add)
            {
                GenerateAdd(generator, optimizationInfo);
                return;
            }

            // Special case the instanceof operator.
            if (this.OperatorType == OperatorType.InstanceOf)
            {
                GenerateInstanceOf(generator, optimizationInfo);
                return;
            }

            // Special case the in operator.
            if (this.OperatorType == OperatorType.In)
            {
                GenerateIn(generator, optimizationInfo);
                return;
            }

            // Special case the relational operators.
            if (this.OperatorType == OperatorType.LessThan ||
                this.OperatorType == OperatorType.LessThanOrEqual ||
                this.OperatorType == OperatorType.GreaterThan ||
                this.OperatorType == OperatorType.GreaterThanOrEqual)
            {
                GenerateRelational(generator, optimizationInfo);
                return;
            }

            // Special case the logical operators.
            if (this.OperatorType == OperatorType.LogicalAnd ||
                this.OperatorType == OperatorType.LogicalOr)
            {
                GenerateLogical(generator, optimizationInfo);
                return;
            }

            // Load the left hand side onto the stack.
            this.Left.GenerateCode(generator, optimizationInfo);

            // Convert the left argument.
            switch (this.OperatorType)
            {
                // Arithmetic operations.
                case OperatorType.Subtract:
                case OperatorType.Multiply:
                case OperatorType.Divide:
                case OperatorType.Modulo:
                    EmitConversion.ToNumber(generator, this.Left.ResultType);
                    break;

                // Bitwise operations.
                case OperatorType.BitwiseAnd:
                case OperatorType.BitwiseOr:
                case OperatorType.BitwiseXor:
                case OperatorType.LeftShift:
                case OperatorType.SignedRightShift:
                case OperatorType.UnsignedRightShift:
                    EmitConversion.ToInt32(generator, this.Left.ResultType);
                    break;

                // Equality operations.
                case OperatorType.Equal:
                case OperatorType.StrictlyEqual:
                case OperatorType.NotEqual:
                case OperatorType.StrictlyNotEqual:
                    EmitConversion.ToAny(generator, this.Left.ResultType);
                    break;
            }

            // Load the right hand side onto the stack.
            this.Right.GenerateCode(generator, optimizationInfo);

            // Convert the right argument.
            switch (this.OperatorType)
            {
                // Arithmetic operations.
                case OperatorType.Subtract:
                case OperatorType.Multiply:
                case OperatorType.Divide:
                case OperatorType.Modulo:
                    EmitConversion.ToNumber(generator, this.Right.ResultType);
                    break;

//.........这里部分代码省略.........

        /// <summary>
        /// Generates CIL for an increment or decrement expression.
        /// </summary>
        /// <param name="generator"> The generator to output the CIL to. </param>
        /// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
        /// <param name="target"> The target to modify. </param>
        /// <param name="postfix"> <c>true</c> if this is the postfix version of the operator;
        /// <c>false</c> otherwise. </param>
        /// <param name="increment"> <c>true</c> if this is the increment operator; <c>false</c> if
        /// this is the decrement operator. </param>
        private void GenerateIncrementOrDecrement(ILGenerator generator, OptimizationInfo optimizationInfo, IReferenceExpression target, bool postfix, bool increment)
        {
            // Note: increment and decrement can produce a number that is out of range if the
            // target is of type Int32.  The only time this should happen is for a loop variable
            // where the range has been carefully checked to make sure an out of range condition
            // cannot happen.

            // Evaluate the left hand side only once.
            target.GenerateReference(generator, optimizationInfo);
            target.DuplicateReference(generator, optimizationInfo); // For the GenerateSet, later on.

            // Get the target value.
            target.GenerateGet(generator, optimizationInfo, true);

            // Convert it to a number.
            if (target.Type != PrimitiveType.Int32)
                EmitConversion.ToNumber(generator, target.Type);

            // If this is PostIncrement or PostDecrement, store the value so it can be returned later.
            var result = generator.CreateTemporaryVariable(target.Type == PrimitiveType.Int32 ? PrimitiveType.Int32 : PrimitiveType.Number);
            if (postfix == true)
            {
                generator.Duplicate();
                generator.StoreVariable(result);
            }

            // Load the increment constant.
            if (target.Type == PrimitiveType.Int32)
                generator.LoadInt32(1);
            else
                generator.LoadDouble(1.0);

            // Add or subtract the constant to the target value.
            if (increment == true)
                generator.Add();
            else
                generator.Subtract();

            // If this is PreIncrement or PreDecrement, store the value so it can be returned later.
            if (postfix == false)
            {
                generator.Duplicate();
                generator.StoreVariable(result);
            }

            // Store the value.
            target.GenerateSet(generator, optimizationInfo, target.Type == PrimitiveType.Int32 ? PrimitiveType.Int32 : PrimitiveType.Number, optimizationInfo.StrictMode);

            // Restore the expression result.
            generator.LoadVariable(result);
            generator.ReleaseTemporaryVariable(result);
        }

        /// <summary>
        /// Pops the value on the stack, converts it to an integer, then pushes the integer result
        /// onto the stack.
        /// </summary>
        /// <param name="generator"> The IL generator. </param>
        /// <param name="fromType"> The type to convert from. </param>
        public static void ToInteger(ILGenerator generator, PrimitiveType fromType)
        {
            // Check that a conversion is actually necessary.
            if (fromType == PrimitiveType.Int32 || fromType == PrimitiveType.UInt32 || fromType == PrimitiveType.Bool)
                return;

            switch (fromType)
            {
                case PrimitiveType.Undefined:
                case PrimitiveType.Null:
                    // Converting from undefined or null produces 0.
                    generator.Pop();
                    generator.LoadInt32(0);
                    break;

                case PrimitiveType.Number:
                    // Converting from a number produces the following:
                    // Any number between -2147483648 and +2147483647 -> itself
                    // Any number smaller than -2147483648 -> -2147483648
                    // Any number larger than +2147483647 -> +2147483647
                    // NaN -> 0

                    // bool isPositiveInfinity = input > 2147483647.0
                    var isPositiveInfinity = generator.CreateTemporaryVariable(typeof(bool));
                    generator.Duplicate();
                    generator.LoadDouble(2147483647.0);
                    generator.CompareGreaterThan();
                    generator.StoreVariable(isPositiveInfinity);

                    // bool notNaN = input == input
                    var notNaN = generator.CreateTemporaryVariable(typeof(bool));
                    generator.Duplicate();
                    generator.Duplicate();
                    generator.CompareEqual();
                    generator.StoreVariable(notNaN);

                    // input = (int)input
                    // Infinity -> -2147483648
                    // -Infinity -> -2147483648
                    // NaN -> -2147483648
                    generator.ConvertToInteger();

                    // input = input & -((int)notNaN)
                    generator.LoadVariable(notNaN);
                    generator.Negate();
                    generator.BitwiseAnd();

                    // input = input - (int)isPositiveInfinity
                    generator.LoadVariable(isPositiveInfinity);
                    generator.Subtract();

                    // The temporary variables are no longer needed.
                    generator.ReleaseTemporaryVariable(notNaN);
                    generator.ReleaseTemporaryVariable(isPositiveInfinity);
                    break;

                case PrimitiveType.String:
                case PrimitiveType.ConcatenatedString:
                case PrimitiveType.Any:
                case PrimitiveType.Object:
                    // Otherwise, fall back to calling TypeConverter.ToInteger()
                    generator.Call(ReflectionHelpers.TypeConverter_ToInteger);
                    break;

                default:
                    throw new NotImplementedException(string.Format("Unsupported primitive type: {0}", fromType));
            }
        }