c# - 在 C# 中获取 vtable 地址？

Question

我愿意使用unsafe。如何获取类虚拟表地址并将其转换为 int？

Answer 1

(编辑:射击 - 忘了你还必须确保它不是内联的 - 见编辑)

你不需要 unsafe，但你确实需要确保方法已经过 JIT(.PrepareMethod 做的):

警告:我不完全确定(没有更多研究)这些数字的长期准确性；我知道它们曾经曾经是准确的，因为我曾经用它来运行时交换方法实现...嘘

using System;
using System.Runtime.CompilerServices;
void Main()
{
    long typeHandle = typeof(Foo).TypeHandle.Value.ToInt64();
    Console.WriteLine("addressOf(typeof(Foo)): 0x{0:x}", typeHandle);

    MethodInfo instanceMethod1 = typeof(Foo).GetMethod("InstanceFunc1");
    RuntimeHelpers.PrepareMethod(instanceMethod1.MethodHandle);
    long addressOfInstanceMethod1 = instanceMethod1.MethodHandle.GetFunctionPointer().ToInt64();
    Console.WriteLine("foo.InstanceFunc1:      0x{0:x}", addressOfInstanceMethod1);

    MethodInfo instanceMethod2 = typeof(Foo).GetMethod("InstanceFunc2");
    RuntimeHelpers.PrepareMethod(instanceMethod2.MethodHandle);
    long addressOfInstanceMethod2 = instanceMethod2.MethodHandle.GetFunctionPointer().ToInt64();
    Console.WriteLine("foo.InstanceFunc2:      0x{0:x}", addressOfInstanceMethod2);

    MethodInfo staticMethod = typeof(Foo).GetMethod("StaticFunc");
    RuntimeHelpers.PrepareMethod(staticMethod.MethodHandle);
    long addressOfStaticMethod = staticMethod.MethodHandle.GetFunctionPointer().ToInt64();
    Console.WriteLine("Foo.StaticFunc:         0x{0:x}", addressOfStaticMethod);
}

public class Foo
{
   [MethodImpl(MethodImplOptions.NoInlining)]
   public static int StaticFunc() { return 1; } 
   [MethodImpl(MethodImplOptions.NoInlining)]
   public int InstanceFunc1() { return 1; } 
   [MethodImpl(MethodImplOptions.NoInlining)]
   public int InstanceFunc2() { return 1; }
}