反射性能优化
using System;using System.Reflection;using System.Reflection.Emit;using System.Collections.Generic;using System.Text;using System.Diagnostics;namespace FastMethodInvoker{ public delegate object FastInvokeHandler(object target, object[] paramters); public delegate void SayHandler(string word); class Program { static object InvokeMethod(FastInvokeHandler invoke, object target, params object[] paramters) { return invoke(null, paramters); } static void Main(string[] args) { Type t = typeof(Person); MethodInfo methodInfo = t.GetMethod("Say"); Person person = new Person(); string word = "hello"; Person p = null; object[] param = new object[] { word, p, 3 }; Stopwatch watch = new Stopwatch(); watch.Start(); for (int i = 0; i < 1000000; i ) { methodInfo.Invoke(person, param); } watch.Stop(); Console.WriteLine("1000000 times invoked by Reflection: " watch.ElapsedMilliseconds "ms"); Stopwatch watch1 = new Stopwatch(); FastInvokeHandler fastInvoker = GetMethodInvoker(methodInfo); watch1.Start(); for (int i = 0; i < 1000000; i ) { fastInvoker(person, param); } watch1.Stop(); Console.WriteLine("1000000 times invoked by FastInvoke: " watch1.ElapsedMilliseconds "ms"); Stopwatch watch2 = new Stopwatch(); watch2.Start(); for (int i = 0; i < 1000000; i ) { person.Say(ref word, out p, 3); } watch2.Stop(); Console.WriteLine("1000000 times invoked by DirectCall: " watch2.ElapsedMilliseconds "ms"); Console.ReadLine(); } private static FastInvokeHandler GetMethodInvoker(MethodInfo methodInfo) { DynamicMethod dynamicMethod = new DynamicMethod(string.Empty, typeof(object), new Type[] { typeof(object), typeof(object[]) }, methodInfo.DeclaringType.Module); ILGenerator il = dynamicMethod.GetILGenerator(); ParameterInfo[] ps = methodInfo.GetParameters(); Type[] paramTypes = new Type[ps.Length]; for (int i = 0; i < paramTypes.Length; i ) { if (ps[i].ParameterType.IsByRef) paramTypes[i] = ps[i].ParameterType.GetElementType(); else paramTypes[i] = ps[i].ParameterType; } LocalBuilder[] locals = new LocalBuilder[paramTypes.Length]; for (int i = 0; i < paramTypes.Length; i ) { locals[i] = il.DeclareLocal(paramTypes[i], true); } for (int i = 0; i < paramTypes.Length; i ) { il.Emit(OpCodes.Ldarg_1); EmitFastInt(il, i); il.Emit(OpCodes.Ldelem_Ref); EmitCastToReference(il, paramTypes[i]); il.Emit(OpCodes.Stloc, locals[i]); } if (!methodInfo.IsStatic) { il.Emit(OpCodes.Ldarg_0); } for (int i = 0; i < paramTypes.Length; i ) { if (ps[i].ParameterType.IsByRef) il.Emit(OpCodes.Ldloca_S, locals[i]); else il.Emit(OpCodes.Ldloc, locals[i]); } if (methodInfo.IsStatic) il.EmitCall(OpCodes.Call, methodInfo, null); else il.EmitCall(OpCodes.Callvirt, methodInfo, null); if (methodInfo.ReturnType == typeof(void)) il.Emit(OpCodes.Ldnull); else EmitBoxIfNeeded(il, methodInfo.ReturnType); for (int i = 0; i < paramTypes.Length; i ) { if (ps[i].ParameterType.IsByRef) { il.Emit(OpCodes.Ldarg_1); EmitFastInt(il, i); il.Emit(OpCodes.Ldloc, locals[i]); if (locals[i].LocalType.IsValueType) il.Emit(OpCodes.Box, locals[i].LocalType); il.Emit(OpCodes.Stelem_Ref); } } il.Emit(OpCodes.Ret); FastInvokeHandler invoder = (FastInvokeHandler)dynamicMethod.CreateDelegate(typeof(FastInvokeHandler)); return invoder; } private static void EmitCastToReference(ILGenerator il, System.Type type) { if (type.IsValueType) { il.Emit(OpCodes.Unbox_Any, type); } else { il.Emit(OpCodes.Castclass, type); } } private static void EmitBoxIfNeeded(ILGenerator il, System.Type type) { if (type.IsValueType) { il.Emit(OpCodes.Box, type); } } private static void EmitFastInt(ILGenerator il, int value) { switch (value) { case -1: il.Emit(OpCodes.Ldc_I4_M1); return; case 0: il.Emit(OpCodes.Ldc_I4_0); return; case 1: il.Emit(OpCodes.Ldc_I4_1); return; case 2: il.Emit(OpCodes.Ldc_I4_2); return; case 3: il.Emit(OpCodes.Ldc_I4_3); return; case 4: il.Emit(OpCodes.Ldc_I4_4); return; case 5: il.Emit(OpCodes.Ldc_I4_5); return; case 6: il.Emit(OpCodes.Ldc_I4_6); return; case 7: il.Emit(OpCodes.Ldc_I4_7); return; case 8: il.Emit(OpCodes.Ldc_I4_8); return; } if (value > -129 && value < 128) { il.Emit(OpCodes.Ldc_I4_S, (SByte)value); } else { il.Emit(OpCodes.Ldc_I4, value); } } } public class Person { public void Say(ref string word, out Person p, int avi) { word = "ttt" avi.ToString(); p = new Person(); } }}
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