C# 快速反射 IL

public class FastInvoke
{
public delegate object FastInvokeHandler(object target, object[] paramters);

static object InvokeMethod(FastInvokeHandler invoke, object target, params object[] paramters)
{
return invoke(null, paramters);
}

public 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);
}
}
}

using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;

namespace FastMethodInvoker
{
    class Program
    {
        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 };
            int TestTimes = 100000; //测试次数，可自行调节看效果

            #region 传统方式反射
            try
            {
                Stopwatch watch = new Stopwatch();
                watch.Start();
                for (int i = 0; i < TestTimes; i++)
                {
                    methodInfo.Invoke(person, param);
                }
                watch.Stop();
                Console.WriteLine(TestTimes.ToString() + " times invoked by Reflection: " + watch.ElapsedMilliseconds + "ms");
            }
            catch (System.Exception ex)
            {
                Console.WriteLine("传统方式反射 直接错误:" + ex.Message);
                Console.WriteLine("传统方式反射 内部错误:" + ex.InnerException.Message);
            }
            #endregion

            #region 快速反射
            try
            {
                Stopwatch watch1 = new Stopwatch();
                FastInvoke.FastInvokeHandler fastInvoker = FastInvoke.GetMethodInvoker(methodInfo);
                watch1.Start();
                for (int i = 0; i < TestTimes; i++)
                {
                    fastInvoker(person, param);
                }
                watch1.Stop();
                Console.WriteLine(TestTimes.ToString() + " times invoked by FastInvoke: " + watch1.ElapsedMilliseconds + "ms");
            }
            catch (System.Exception ex)
            {
                Console.WriteLine("快速反射 错误:" + ex.Message);
            }
            #endregion

            #region 直接调用
            try
            {
                Stopwatch watch2 = new Stopwatch();
                watch2.Start();
                for (int i = 0; i < TestTimes; i++)
                {
                    person.Say(ref word, out p, 3);
                }
                watch2.Stop();
                Console.WriteLine(TestTimes.ToString() + " times invoked by DirectCall: " + watch2.ElapsedMilliseconds + "ms");
            }
            catch (System.Exception ex)
            {
                Console.WriteLine("直接调用 错误:" + ex.Message);
            }
            #endregion
            
            Console.ReadLine();
        }
    }

    public class Person
    {
        public void Say(ref string word, out Person p, int avi)
        {
            word = "ttt" + avi.ToString();
            p = new Person();

            //throw new System.Exception("出错了哦");
        }
    }
}