C# ILGenerator.BranchIfNotNull方法代码示例

        /// <summary>
        /// Generates IL for the script.
        /// </summary>
        /// <param name="generator"> The generator to output the CIL to. </param>
        /// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
        protected override void GenerateCode(ILGenerator generator, OptimizationInfo optimizationInfo)
        {
            // Declare a variable to store the eval result.
            optimizationInfo.EvalResult = generator.DeclareVariable(typeof(object));

            if (this.StrictMode == true)
            {
                // Create a new scope.
                this.InitialScope.GenerateScopeCreation(generator, optimizationInfo);
            }

            // Verify the scope is correct.
            VerifyScope(generator);

            // Initialize any declarations.
            this.InitialScope.GenerateDeclarations(generator, optimizationInfo);

            // Generate the main body of code.
            this.AbstractSyntaxTree.GenerateCode(generator, optimizationInfo);

            // Make the return value from the method the eval result.
            generator.LoadVariable(optimizationInfo.EvalResult);

            // If the result is null, convert it to undefined.
            var end = generator.CreateLabel();
            generator.Duplicate();
            generator.BranchIfNotNull(end);
            generator.Pop();
            EmitHelpers.EmitUndefined(generator);
            generator.DefineLabelPosition(end);
        }

//.........这里部分代码省略.........
                        var cacheKey = generator.DeclareVariable(typeof(object));
                        var cachedIndex = generator.DeclareVariable(typeof(int));

                        // Store the object into a temp variable.
                        var objectInstance = generator.DeclareVariable(PrimitiveType.Object);
                        generator.StoreVariable(objectInstance);

                        // if (__object_cacheKey != object.InlineCacheKey)
                        generator.LoadVariable(cacheKey);
                        generator.LoadVariable(objectInstance);
                        generator.Call(ReflectionHelpers.ObjectInstance_InlineCacheKey);
                        var elseClause = generator.CreateLabel();
                        generator.BranchIfEqual(elseClause);

                        // value = object.InlineGetProperty("property", out __object_property_cachedIndex, out __object_cacheKey)
                        generator.LoadVariable(objectInstance);
                        generator.LoadString(this.Name);
                        generator.LoadAddressOfVariable(cachedIndex);
                        generator.LoadAddressOfVariable(cacheKey);
                        generator.Call(ReflectionHelpers.ObjectInstance_InlineGetPropertyValue);

                        var endOfIf = generator.CreateLabel();
                        generator.Branch(endOfIf);

                        // else
                        generator.DefineLabelPosition(elseClause);

                        // value = object.InlinePropertyValues[__object_property_cachedIndex];
                        generator.LoadVariable(objectInstance);
                        generator.Call(ReflectionHelpers.ObjectInstance_InlinePropertyValues);
                        generator.LoadVariable(cachedIndex);
                        generator.LoadArrayElement(typeof(object));

                        // End of the if statement
                        generator.DefineLabelPosition(endOfIf);

                        // Check if the value is null.
                        generator.Duplicate();
                        generator.BranchIfNotNull(endOfGet);
                        if (scope.ParentScope != null)
                            generator.Pop();

                    }
                    else
                    {

                        // Gets the value of a variable in an object scope.
                        if (scopeVariable == null)
                            EmitHelpers.LoadScope(generator);
                        else
                            generator.LoadVariable(scopeVariable);
                        generator.CastClass(typeof(ObjectScope));
                        generator.Call(ReflectionHelpers.ObjectScope_ScopeObject);
                        generator.LoadString(this.Name);
                        generator.Call(ReflectionHelpers.ObjectInstance_GetPropertyValue_Object);

                        // Check if the value is null.
                        generator.Duplicate();
                        generator.BranchIfNotNull(endOfGet);
                        if (scope.ParentScope != null)
                            generator.Pop();

                    }
                }

                // Try the parent scope.
                if (scope.ParentScope != null && scope.ExistsAtRuntime == true)
                {
                    if (scopeVariable == null)
                    {
                        scopeVariable = generator.CreateTemporaryVariable(typeof(Scope));
                        EmitHelpers.LoadScope(generator);
                    }
                    else
                    {
                        generator.LoadVariable(scopeVariable);
                    }
                    generator.Call(ReflectionHelpers.Scope_ParentScope);
                    generator.StoreVariable(scopeVariable);
                }
                scope = scope.ParentScope;

            } while (scope != null);

            // Throw an error if the name does not exist and throwIfUnresolvable is true.
            if (scope == null && throwIfUnresolvable == true)
                EmitHelpers.EmitThrow(generator, ErrorType.ReferenceError, this.Name + " is not defined", optimizationInfo);

            // Release the temporary variable.
            if (scopeVariable != null)
                generator.ReleaseTemporaryVariable(scopeVariable);

            // Define a label at the end.
            generator.DefineLabelPosition(endOfGet);

            // Object scope references may have side-effects (because of getters) so if the value
            // is to be ignored we evaluate the value then pop the value from the stack.
            //if (optimizationInfo.SuppressReturnValue == true)
            //    generator.Pop();
        }

        /// <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)
        {
            // Note: we use GetRawOperand() so that grouping operators are not ignored.
            var operand = this.GetRawOperand(0);

            // There is only one operand, and it can be either a reference or a function call.
            // We need to split the operand into a function and some arguments.
            // If the operand is a reference, it is equivalent to a function call with no arguments.
            if (operand is FunctionCallExpression)
            {
                // Emit the function instance first.
                var function = ((FunctionCallExpression)operand).Target;
                function.GenerateCode(generator, optimizationInfo);
                EmitConversion.ToAny(generator, function.ResultType);
            }
            else
            {
                // Emit the function instance first.
                operand.GenerateCode(generator, optimizationInfo);
                EmitConversion.ToAny(generator, operand.ResultType);
            }

            // Check the object really is a function - if not, throw an exception.
            generator.IsInstance(typeof(Library.FunctionInstance));
            generator.Duplicate();
            var endOfTypeCheck = generator.CreateLabel();
            generator.BranchIfNotNull(endOfTypeCheck);

            // Throw an nicely formatted exception.
            var targetValue = generator.CreateTemporaryVariable(typeof(object));
            generator.StoreVariable(targetValue);
            EmitHelpers.LoadScriptEngine(generator);
            generator.LoadString("TypeError");
            generator.LoadString("The new operator requires a function, found a '{0}' instead");
            generator.LoadInt32(1);
            generator.NewArray(typeof(object));
            generator.Duplicate();
            generator.LoadInt32(0);
            generator.LoadVariable(targetValue);
            generator.Call(ReflectionHelpers.TypeUtilities_TypeOf);
            generator.StoreArrayElement(typeof(object));
            generator.Call(ReflectionHelpers.String_Format);
            generator.LoadInt32(optimizationInfo.SourceSpan.StartLine);
            generator.LoadStringOrNull(optimizationInfo.Source.Path);
            generator.LoadStringOrNull(optimizationInfo.FunctionName);
            generator.NewObject(ReflectionHelpers.JavaScriptException_Constructor_Error);
            generator.Throw();
            generator.DefineLabelPosition(endOfTypeCheck);
            generator.ReleaseTemporaryVariable(targetValue);

            if (operand is FunctionCallExpression)
            {
                // Emit an array containing the function arguments.
                ((FunctionCallExpression)operand).GenerateArgumentsArray(generator, optimizationInfo);
            }
            else
            {
                // Emit an empty array.
                generator.LoadInt32(0);
                generator.NewArray(typeof(object));
            }

            // Call FunctionInstance.ConstructLateBound(argumentValues)
            generator.Call(ReflectionHelpers.FunctionInstance_ConstructLateBound);
        }

        /// <summary>
        /// Generates CIL for the in operator.
        /// </summary>
        /// <param name="generator"> The generator to output the CIL to. </param>
        /// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
        private void GenerateIn(ILGenerator generator, OptimizationInfo optimizationInfo)
        {
            // Emit the left-hand side expression and convert it to a string.
            this.Left.GenerateCode(generator, optimizationInfo);
            EmitConversion.ToString(generator, this.Left.ResultType);

            // Store the left-hand side expression in a temporary variable.
            var temp = generator.CreateTemporaryVariable(typeof(string));
            generator.StoreVariable(temp);

            // Emit the right-hand side expression.
            this.Right.GenerateCode(generator, optimizationInfo);
            EmitConversion.ToAny(generator, this.Right.ResultType);

            // Check the right-hand side is a javascript object - if not, throw an exception.
            generator.IsInstance(typeof(Library.ObjectInstance));
            generator.Duplicate();
            var endOfTypeCheck = generator.CreateLabel();
            generator.BranchIfNotNull(endOfTypeCheck);

            // Throw an nicely formatted exception.
            var rightValue = generator.CreateTemporaryVariable(typeof(object));
            generator.StoreVariable(rightValue);
            EmitHelpers.LoadScriptEngine(generator);
            generator.LoadString("TypeError");
            generator.LoadString("The in operator expected an object, but found '{0}' instead");
            generator.LoadInt32(1);
            generator.NewArray(typeof(object));
            generator.Duplicate();
            generator.LoadInt32(0);
            generator.LoadVariable(rightValue);
            generator.Call(ReflectionHelpers.TypeUtilities_TypeOf);
            generator.StoreArrayElement(typeof(object));
            generator.Call(ReflectionHelpers.String_Format);
            generator.LoadInt32(optimizationInfo.SourceSpan.StartLine);
            generator.LoadStringOrNull(optimizationInfo.Source.Path);
            generator.LoadStringOrNull(optimizationInfo.FunctionName);
            generator.NewObject(ReflectionHelpers.JavaScriptException_Constructor_Error);
            generator.Throw();
            generator.DefineLabelPosition(endOfTypeCheck);
            generator.ReleaseTemporaryVariable(rightValue);

            // Load the left-hand side expression from the temporary variable.
            generator.LoadVariable(temp);

            // Call ObjectInstance.HasProperty(object)
            generator.Call(ReflectionHelpers.ObjectInstance_HasProperty);

            // Allow the temporary variable to be reused.
            generator.ReleaseTemporaryVariable(temp);
        }

        /// <summary>
        /// Generates a method that does type conversion and calls the bound method.
        /// </summary>
        /// <param name="generator"> The ILGenerator used to output the body of the method. </param>
        /// <param name="argumentCount"> The number of arguments that will be passed to the delegate. </param>
        /// <returns> A delegate that does type conversion and calls the method represented by this
        /// object. </returns>
        protected override void GenerateStub(ILGenerator generator, int argumentCount)
        {
            // Here is what we are going to generate.
            //private static object SampleBinder(ScriptEngine engine, object thisObject, object[] arguments)
            //{
            //    // Target function signature: int (bool, int, string, object).
            //    bool param1;
            //    int param2;
            //    string param3;
            //    object param4;
            //    param1 = arguments[0] != 0;
            //    param2 = TypeConverter.ToInt32(arguments[1]);
            //    param3 = TypeConverter.ToString(arguments[2]);
            //    param4 = Undefined.Value;
            //    return thisObject.targetMethod(param1, param2, param3, param4);
            //}

            // Find the target method.
            var binderMethod = this.buckets[Math.Min(argumentCount, this.buckets.Length - 1)];

            // Constrain the number of apparent arguments to within the required bounds.
            int minArgumentCount = binderMethod.RequiredParameterCount;
            int maxArgumentCount = binderMethod.RequiredParameterCount + binderMethod.OptionalParameterCount;
            if (binderMethod.HasParamArray == true)
                maxArgumentCount = int.MaxValue;

            foreach (var argument in binderMethod.GenerateArguments(generator, Math.Min(Math.Max(argumentCount, minArgumentCount), maxArgumentCount)))
            {
                switch (argument.Source)
                {
                    case BinderArgumentSource.ScriptEngine:
                        // Load the "engine" parameter passed by the client.
                        generator.LoadArgument(0);
                        break;

                    case BinderArgumentSource.ThisValue:
                        // Load the "this" parameter passed by the client.
                        generator.LoadArgument(1);

                        bool inheritsFromObjectInstance = typeof(ObjectInstance).IsAssignableFrom(argument.Type);
                        if (argument.Type.IsClass == true && inheritsFromObjectInstance == false &&
                            argument.Type != typeof(string) && argument.Type != typeof(object))
                        {
                            // If the "this" object is an unsupported class, pass it through unmodified.
                            generator.CastClass(argument.Type);
                        }
                        else
                        {
                            if (argument.Type != typeof(object))
                            {
                                // If the target "this" object type is not of type object, throw an error if
                                // the value is undefined or null.
                                generator.Duplicate();
                                var temp = generator.CreateTemporaryVariable(typeof(object));
                                generator.StoreVariable(temp);
                                generator.LoadArgument(0);
                                generator.LoadVariable(temp);
                                generator.LoadString(binderMethod.Name);
                                generator.Call(ReflectionHelpers.TypeUtilities_VerifyThisObject);
                                generator.ReleaseTemporaryVariable(temp);
                            }

                            // Convert to the target type.
                            EmitTypeConversion(generator, typeof(object), argument.Type);

                            if (argument.Type != typeof(ObjectInstance) && inheritsFromObjectInstance == true)
                            {
                                // EmitConversionToObjectInstance can emit null if the toType is derived from ObjectInstance.
                                // Therefore, if the value emitted is null it means that the "thisObject" is a type derived
                                // from ObjectInstance (e.g. FunctionInstance) and the value provided is a different type
                                // (e.g. ArrayInstance).  In this case, throw an exception explaining that the function is
                                // not generic.
                                var endOfThrowLabel = generator.CreateLabel();
                                generator.Duplicate();
                                generator.BranchIfNotNull(endOfThrowLabel);
                                generator.LoadArgument(0);
                                EmitHelpers.EmitThrow(generator, "TypeError", string.Format("The method '{0}' is not generic", binderMethod.Name));
                                generator.DefineLabelPosition(endOfThrowLabel);
                            }
                        }
                        break;

                    case BinderArgumentSource.InputParameter:
                        if (argument.InputParameterIndex < argumentCount)
                        {
                            // Load the argument onto the stack.
                            generator.LoadArgument(2);
                            generator.LoadInt32(argument.InputParameterIndex);
                            generator.LoadArrayElement(typeof(object));

                            // Get some flags that apply to the parameter.
                            var parameterFlags = JSParameterFlags.None;
                            var parameterAttribute = argument.GetCustomAttribute<JSParameterAttribute>();
//.........这里部分代码省略.........

        /// <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)
        {
            // Check if this is a direct call to eval().
            if (this.Target is NameExpression && ((NameExpression)this.Target).Name == "eval")
            {
                GenerateEval(generator, optimizationInfo);
                return;
            }

            // Emit the function instance first.
            ILLocalVariable targetBase = null;
            if (this.Target is MemberAccessExpression)
            {
                // The function is a member access expression (e.g. "Math.cos()").

                // Evaluate the left part of the member access expression.
                var baseExpression = ((MemberAccessExpression)this.Target).Base;
                baseExpression.GenerateCode(generator, optimizationInfo);
                EmitConversion.ToAny(generator, baseExpression.ResultType);
                targetBase = generator.CreateTemporaryVariable(typeof(object));
                generator.StoreVariable(targetBase);

                // Evaluate the right part of the member access expression.
                var memberAccessExpression = new MemberAccessExpression(((MemberAccessExpression)this.Target).Operator);
                memberAccessExpression.Push(new TemporaryVariableExpression(targetBase));
                memberAccessExpression.Push(((MemberAccessExpression)this.Target).GetOperand(1));
                memberAccessExpression.GenerateCode(generator, optimizationInfo);
                EmitConversion.ToAny(generator, this.Target.ResultType);
            }
            else
            {
                // Something else (e.g. "eval()").
                this.Target.GenerateCode(generator, optimizationInfo);
                EmitConversion.ToAny(generator, this.Target.ResultType);
            }

            // Check the object really is a function - if not, throw an exception.
            generator.IsInstance(typeof(Library.FunctionInstance));
            generator.Duplicate();
            var endOfTypeCheck = generator.CreateLabel();
            generator.BranchIfNotNull(endOfTypeCheck);

            // Throw an nicely formatted exception.
            generator.Pop();
            EmitHelpers.EmitThrow(generator, "TypeError", string.Format("'{0}' is not a function", this.Target.ToString()));
            generator.DefineLabelPosition(endOfTypeCheck);

            // Pass in the path, function name and line.
            generator.LoadStringOrNull(optimizationInfo.Source.Path);
            generator.LoadStringOrNull(optimizationInfo.FunctionName);
            generator.LoadInt32(optimizationInfo.SourceSpan.StartLine);

            // Generate code to produce the "this" value.  There are three cases.
            if (this.Target is NameExpression)
            {
                // 1. The function is a name expression (e.g. "parseInt()").
                //    In this case this = scope.ImplicitThisValue, if there is one, otherwise undefined.
                ((NameExpression)this.Target).GenerateThis(generator);
            }
            else if (this.Target is MemberAccessExpression)
            {
                // 2. The function is a member access expression (e.g. "Math.cos()").
                //    In this case this = Math.
                //var baseExpression = ((MemberAccessExpression)this.Target).Base;
                //baseExpression.GenerateCode(generator, optimizationInfo);
                //EmitConversion.ToAny(generator, baseExpression.ResultType);
                generator.LoadVariable(targetBase);
            }
            else
            {
                // 3. Neither of the above (e.g. "(function() { return 5 })()")
                //    In this case this = undefined.
                EmitHelpers.EmitUndefined(generator);
            }

            // Emit an array containing the function arguments.
            GenerateArgumentsArray(generator, optimizationInfo);

            // Call FunctionInstance.CallLateBound(thisValue, argumentValues)
            generator.Call(ReflectionHelpers.FunctionInstance_CallWithStackTrace);

            // Allow reuse of the temporary variable.
            if (targetBase != null)
                generator.ReleaseTemporaryVariable(targetBase);
        }

        /// <summary>
        /// Pops the value on the stack, converts it to an object, then pushes the result onto the
        /// stack.
        /// </summary>
        /// <param name="generator"> The IL generator. </param>
        /// <param name="fromType"> The type to convert from. </param>
        internal static void EmitConversionToObject(ILGenerator generator, Type fromType)
        {
            // If the from type is a reference type, check for null.
            ILLabel endOfNullCheck = null;
            if (fromType.IsValueType == false)
            {
                var startOfElse = generator.CreateLabel();
                endOfNullCheck = generator.CreateLabel();
                generator.Duplicate();
                generator.BranchIfNotNull(startOfElse);
                generator.Pop();
                EmitHelpers.EmitNull(generator);
                generator.Branch(endOfNullCheck);
                generator.DefineLabelPosition(startOfElse);
            }

            switch (Type.GetTypeCode(fromType))
            {
                case TypeCode.Boolean:
                    generator.Box(typeof(bool));
                    break;
                case TypeCode.Byte:
                    generator.Box(typeof(int));
                    break;
                case TypeCode.Char:
                    generator.LoadInt32(1);
                    generator.NewObject(ReflectionHelpers.String_Constructor_Char_Int);
                    break;
                
                case TypeCode.DBNull:
                    throw new NotSupportedException("DBNull is not a supported return type.");
                case TypeCode.Decimal:
                    generator.Call(ReflectionHelpers.Decimal_ToDouble);
                    generator.Box(typeof(double));
                    break;
                case TypeCode.Double:
                    generator.Box(typeof(double));
                    break;
                case TypeCode.Empty:
                    throw new NotSupportedException("Empty is not a supported return type.");
                case TypeCode.Int16:
                    generator.Box(typeof(int));
                    break;
                case TypeCode.Int32:
                    generator.Box(typeof(int));
                    break;
                case TypeCode.Int64:
                    generator.ConvertToDouble();
                    generator.Box(typeof(double));
                    break;

                case TypeCode.DateTime:
                case TypeCode.Object:
                    // Check if the type must be wrapped with a ClrInstanceWrapper.
                    // Note: if the type is a value type it cannot be a primitive or it would
                    // have been handled elsewhere in the switch.
                    ILLabel endOfWrapCheck = null;
                    if (fromType.IsValueType == false)
                    {
                        generator.Duplicate();
                        generator.Call(ReflectionHelpers.TypeUtilities_IsPrimitiveOrObject);
                        endOfWrapCheck = generator.CreateLabel();
                        generator.BranchIfTrue(endOfWrapCheck);
                    }

                    // The type must be wrapped.
                    var temp = generator.CreateTemporaryVariable(fromType);
                    generator.StoreVariable(temp);
                    generator.LoadArgument(0);
                    generator.LoadVariable(temp);
                    if (fromType.IsValueType == true)
                        generator.Box(fromType);
                    generator.ReleaseTemporaryVariable(temp);
                    generator.NewObject(ReflectionHelpers.ClrInstanceWrapper_Constructor);
                    
                    // End of wrap check.
                    if (fromType.IsValueType == false)
                        generator.DefineLabelPosition(endOfWrapCheck);
                    break;

                case TypeCode.SByte:
                    generator.Box(typeof(int));
                    break;
                case TypeCode.Single:
                    generator.Box(typeof(double));
                    break;
                case TypeCode.String:
                    break;
                case TypeCode.UInt16:
                    generator.Box(typeof(int));
                    break;
                case TypeCode.UInt32:
                    generator.Box(typeof(uint));
                    break;
//.........这里部分代码省略.........