我能正确理解这个MSIL代码吗？

Question

我在C#中有以下代码

// test.Program
private static void Main()
{
    int x = 5;
    int y = 100;
    Console.WriteLine(y + ", " + x);
}

而且我正在阅读IL代码,我之前从未编写过程序集,所以我问我每行的功能是否正确.

.method private hidebysig static 
    void Main () cil managed 
{
    // Method begins at RVA 0x2058
    // Code size 33 (0x21)
    .maxstack 3 // maximum stack in this method is 3
    .entrypoint // method is initial entry point
    .locals init ( // reserves memory for x and y variables
        [0] int32 x, // x variable is reserved on position 0 of the stack
        [1] int32 y  // y variable is reserved on position 1 of the stack
    )
    IL_0000: ldc.i4.5     // integer of 4 bytes in size and the value of 5 is loaded onto the evaluation stack position 0
    IL_0001: stloc.0      // put evaluation stack position 0 into the stack position 0, the evaluation stack is emptied
    IL_0002: ldc.i4.s 100 // integer of 4 bytes in size and the value of 100 is loaded onto the evaluation stack position 0
    IL_0004: stloc.1      // put evaluation stack position 0 onto the stack position 1, the evaluation stack is emptied
    IL_0005: ldloc.1      // load stack position 1 into the evaluation stack position 0
    IL_0006: box [mscorlib]System.Int32 // box last valuetype placed on evaluation stack, replace valuetype with reference on evaluation stack position 0, do not empty stack
    IL_000b: ldstr ", "   // put reference to string on evaluation stack position 1
    IL_0010: ldloc.0      // load stack position 0 into the evaluation stack position 2
    IL_0011: box [mscorlib]System.Int32 // box last valuetype placed on evaluation stack, replace valuetype with reference on evaluation stack position 0, do not empty stack
    IL_0016: call string [mscorlib]System.String::Concat(object, object, object) // call Concat, pass values on evaluation stack, empty evaluation stack, put result of concat on evaluationstack
    IL_001b: call void [mscorlib]System.Console::WriteLine(string) // pass first value in evaluation stack
    IL_0020: ret         // return
} // end of method Program::Main

我能正确理解这个程序吗？

Answer 1

差不多; 我唯一澄清的是框(IL_0006和IL_0011)是特定于类型的,因此它显式地构造了一个类型的框int(它不仅仅是"最后一个值类型").

此外,"空评估堆栈"具有误导性; 这不太对 - 例如,call消耗一定数量的头寸 - 它不会"清空"它.有从来没有一个"空计算堆栈"语义-它总是"消耗值的数量,放回到一个数值的"(某一个可能为零).