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我已经在调试模式下编译了一些测试代码，并使用 ILSpy 反映了生成的程序集。这是我得到的 IL：

.class private auto ansi beforefieldinit ArrayListBoxAndUnBox.Program
extends [mscorlib]System.Object
   {
// Nested Types
.class nested public auto ansi beforefieldinit Point
    extends [mscorlib]System.Object
{
    // Fields
    .field public int32 x
    .field public int32 y

    // Methods
    .method public hidebysig specialname rtspecialname 
        instance void .ctor () cil managed 
    {
        // Method begins at RVA 0x209f
        // Code size 7 (0x7)
        .maxstack 8

        IL_0000: ldarg.0
        IL_0001: call instance void [mscorlib]System.Object::.ctor()
        IL_0006: ret
    } // end of method Point::.ctor

} // end of class Point


// Methods
.method private hidebysig static 
    void Main (
        string[] args
    ) cil managed 
{
    // Method begins at RVA 0x2050
    // Code size 59 (0x3b)
    .maxstack 2
    .entrypoint
    .locals init (
        [0] class [mscorlib]System.Collections.ArrayList list,
        [1] int32 i,
        [2] class ArrayListBoxAndUnBox.Program/Point p
    )

    IL_0000: nop
    IL_0001: newobj instance void [mscorlib]System.Collections.ArrayList::.ctor()
    IL_0006: stloc.0
    IL_0007: ldloc.0
    IL_0008: ldc.i4.1
    IL_0009: box [mscorlib]System.Int32
    IL_000e: callvirt instance int32 [mscorlib]System.Collections.ArrayList::Add(object)
    IL_0013: pop
    IL_0014: ldloc.0
    IL_0015: ldc.i4.0
    IL_0016: callvirt instance object [mscorlib]System.Collections.ArrayList::get_Item(int32)
    IL_001b: unbox.any [mscorlib]System.Int32
    IL_0020: stloc.1
    IL_0021: ldloc.0
    IL_0022: newobj instance void ArrayListBoxAndUnBox.Program/Point::.ctor()
    IL_0027: callvirt instance int32 [mscorlib]System.Collections.ArrayList::Add(object)
    IL_002c: pop
    IL_002d: ldloc.0
    IL_002e: ldc.i4.1
    IL_002f: callvirt instance object [mscorlib]System.Collections.ArrayList::get_Item(int32)
    IL_0034: castclass ArrayListBoxAndUnBox.Program/Point
    IL_0039: stloc.2
    IL_003a: ret
} // end of method Program::Main

.method public hidebysig specialname rtspecialname 
    instance void .ctor () cil managed 
{
    // Method begins at RVA 0x2097
    // Code size 7 (0x7)
    .maxstack 8

    IL_0000: ldarg.0
    IL_0001: call instance void [mscorlib]System.Object::.ctor()
    IL_0006: ret
} // end of method Program::.ctor

} // end of class ArrayListBoxAndUnBox.Program

我看到 .maxstack 设置为 2，但是当我手动查看代码时，有时会在评估堆栈上获得 3 个元素。为什么？我是一个糟糕的 IL 堆栈计数器，还是这背后有什么意义？

在我的世界中，IL_0014 的第一个 ldloc.0 从未被删除，但也许只有我没有了解 callvirt 到 get_Item 的工作原理。当我到达 IL_0014 时，我必须在我的堆栈文件上列出对列表的引用，然后在 IL_0015 处，当 0 被推入评估堆栈时，程序违反了 .maxstack。

我是新手，所以肯定有什么不对的地方。也许我的计数是正确的，而我对 .maxstack 的理解是错误的，或者可能是相反的。有人可以告诉我我对 .maxstack 的理解是否错误，即 .maxstack 在运行时显示堆栈上的最大元素。或者如果我的计数是错误的？添加是否删除对列表实例的引用？

编辑：这是我的计数方式。计数是在 IL 代码运行之后：

IL_0000: 0 on stack
IL_0001: 1 on stack (the reference to array list)
IL_0006: 0 on stack
IL_0007: 1 on stack (the reference to arraylist)
IL_0008: 2 on stack (reference to arraylist and int 1)
IL_0009: 2 on stack (refernce to arraylist and reference to object that wrap 1)
IL_000e: 2 on stack (reference to arraylist and index to the added boxed int object)
IL_0013: 1 on stack (reference to arraylist)
IL_0014: 2 on stack (reference to arraylist and reference to arraylist)
IL_0015: 3 on stack (reference to arraylist and reference to arraylist and int 0)

我没有计算其余的，因为我知道我做错了。

谢谢

4

1 回答 1

9

很难看出你哪里出错了。左侧注释的堆栈深度，在指令执行后：

0    IL_0000: nop
1    IL_0001: newobj instance void [mscorlib]System.Collections.ArrayList::.ctor()
0    IL_0006: stloc.0
1    IL_0007: ldloc.0
2    IL_0008: ldc.i4.1
2    IL_0009: box [mscorlib]System.Int32
1    IL_000e: callvirt instance int32 [mscorlib]System.Collections.ArrayList::Add(object)
0    IL_0013: pop
1    IL_0014: ldloc.0
2    IL_0015: ldc.i4.0
1    IL_0016: callvirt instance object [mscorlib]System.Collections.ArrayList::get_Item(int32)
1    IL_001b: unbox.any [mscorlib]System.Int32
0    IL_0020: stloc.1
1    IL_0021: ldloc.0
2    IL_0022: newobj instance void ArrayListBoxAndUnBox.Program/Point::.ctor()
1    IL_0027: callvirt instance int32 [mscorlib]System.Collections.ArrayList::Add(object)
0    IL_002c: pop
1    IL_002d: ldloc.0
2    IL_002e: ldc.i4.1
1    IL_002f: callvirt instance object [mscorlib]System.Collections.ArrayList::get_Item(int32)
1    IL_0034: castclass ArrayListBoxAndUnBox.Program/Point
0    IL_0039: stloc.2
0    IL_003a: ret

唯一重要的是 ArrayList.Add() 调用。它弹出两个堆栈值，ArrayList 对象引用和 Add() 参数。并推回一个，Add() 的返回值。

编辑后：这确实是你出错的地方。

于 2013-10-24T20:05:24.330 回答