Emit学习 - IL - 值类型和引用类型(补)

Posted 2020-08-16 Sniper_ZL

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上周末回家去享受生活了, 工作是为了更好的生活嘛, 所以我把生活, 工作分的比较开. 这几天不是很忙, 在学习工作技能的同时, 发点博文, 也算是做一个学习笔记

上篇中, 贴出的地址里面那位哥, 也有一篇值类型和引用类型的文章

来源:http://www.cnblogs.com/yingql/archive/2009/03/23/1420026.html

我这个和他的那个稍有不同, 各位看官, 请!

一、示例

public class Person
    {
        public string Name { get; set; }

        public int Age { get; set; }
    }

    class Program
    {
        private Random rand = new Random(DateTime.Now.Millisecond);

        private Person person = new Person { Name = "Elvin", Age = 26 };

        private string pro = "pro";

        private double dou = 3.14;

        static void Main(string[] args)
        {
            Console.WriteLine("Main");
            Console.ReadKey();
        }
    }

反编译Program的构造函数, 代码如下:

public Program()
{
    this.rand = new Random(DateTime.Now.Millisecond);
    Person person = new Person {
        Name = "Elvin",
        Age = 0x1a
    };
    this.person = person;
    this.pro = "pro";
    this.dou = 3.14;
}

    .method public hidebysig specialname rtspecialname instance void .ctor() cil managed
{
    .maxstack 3
    .locals init (
        [0] class ConsoleApplication3.Person person,
        [1] valuetype [mscorlib]System.DateTime time)

    L_0000: ldarg.0    //加载this, 是一个地址, 将this沉底, 为一会的this.rand = new Random()服务

    L_0001: call valuetype [mscorlib]System.DateTime [mscorlib]System.DateTime::get_Now()
    L_0006: stloc.1   //初始化time, 为当前时间
    L_0007: ldloca.s time  //加载time的地址, 为什么加载地址呢, 一会详细介绍,  容我卖个关子 (1)
    L_0009: call instance int32 [mscorlib]System.DateTime::get_Millisecond() //调用结构体Datetime的方法

    L_000e: newobj instance void [mscorlib]System.Random::.ctor(int32)  //new Random(), 将对象放入堆中, 然后把指向此对象的地址压栈
    L_0013: stfld class [mscorlib]System.Random ConsoleApplication3.Program::rand  //把刚刚得到的地址赋给rand, 实现this.rand = new Random()功能

    L_0018: ldarg.0 //加载this地址,将this沉底, 为一会的this.person=person服务

    L_0019: newobj instance void ConsoleApplication3.Person::.ctor()  //new Person()
    L_001e: stloc.0 //person = new Person(), 这里的person并不是this.person, 注意
    L_001f: ldloc.0 //加载person, 为什么此处是用的ldloc, 而不是ldloca呢? 答案马上揭晓
    L_0020: ldstr "Elvin"  //加载 "Elvin" 字符串
    L_0025: callvirt instance void ConsoleApplication3.Person::set_Name(string) //person.Name = "Elvin"
    L_002a: nop 

    L_002b: ldloc.0 
    L_002c: ldc.i4.s 0x1a
    L_002e: callvirt instance void ConsoleApplication3.Person::set_Age(int32)
    L_0033: nop 

    L_0034: ldloc.0 //加载person, 不是this.person
    L_0035: stfld class ConsoleApplication3.Person ConsoleApplication3.Program::person  //给this.person赋值, this.person=person

    L_003a: ldarg.0    //加载this, 这里加载this做什么? (2)
    L_003b: ldstr "pro"  //加载"pro"字符串
    L_0040: stfld string ConsoleApplication3.Program::pro  //this.pro = "pro"

    L_0045: ldarg.0 
    L_0046: ldc.r8 3.14
    L_004f: stfld float64 ConsoleApplication3.Program::dou
    L_0054: ldarg.0 
    L_0055: call instance void [mscorlib]System.Object::.ctor()
    L_005a: nop 
    L_005b: ret 
}