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if 语句工作不正确 - 反汇编对我来说没有任何解释

发布于 2024-12-26 18:28:50 字数 14161 浏览 1 评论 0原文

我遇到了一个非常奇怪的问题，并且一直困扰着我。

我正在开发一些连接到网络服务的类库。该库由桌面应用程序使用。

在我现在的代码中：

Int32 errorCode32 = errorCode;
Int32 errorTimeout = 300;

if (errorCode32.Equals(errorTimeout) == false)
{
    System.Console.Out.WriteLine("aaa");
    return;
}

where errorCode equals to 300。所以乍一看，如果 errorCode == 300 则 if 语句内的代码不应该被执行，因为它被定义为仅当 errorCode 为时才执行不等于300。

到现在为止一切都清楚了，但现在整个乐趣开始了。

应用程序正在运行，并且执行具有上述代码片段的方法。 errorCode 等于 300，预期结果是应用程序不会执行 if 语句内的任何代码，因为整个语句为 false。但实际上应用程序进入“if”内部并立即跳到“return”语句。 System.Console.Out...永远不会执行。如果我将干净的“return”语句替换为“throw new SomeException()”，

Int32 errorCode32 = errorCode;
Int32 errorTimeout = 300;

if (errorCode32.Equals(errorTimeout) == false)
{
    System.Console.Out.WriteLine("aaa");
    throw new SomeException();
}

我将得到相同的结果。应用程序进入 if 语句（注意：[errorCode32.Equals(errorTimeout) == false] 在我的情况下为 false），不执行 Console.Out... 但抛出 SomeException。

我多次重建了所有内容，删除了所有二进制文件，甚至从磁盘中删除了整个项目，然后再次从存储库将其检索到干净的文件夹。

我很困惑，以至于我什至反汇编了代码，看看会发生什么（即使我不是汇编专家）。但结果对我来说很奇怪。

反汇编代码如下：

    50:                 Int32 errorCode32 = errorCode;
000000e5  mov         eax,dword ptr [ebp-50h] 
000000e8  mov         dword ptr [ebp-54h],eax 
    51:                 Int32 errorTimeout = 300;
000000eb  mov         dword ptr [ebp-58h],12Ch 
    52: 
    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }

当我调试指令时，我可以理解发生了什么，直到行：

00000104  mov         dword ptr [ebp-48h],eax

我期望存储在 eax 中的值将被复制到位置“dword ptr [ebp-48h]”并且应用程序将转到下一行（00000107）。但这并没有发生。当我尝试跨过第 00000104 行时，应用程序立即跳转到

00000134  mov         eax,dword ptr ds:[0302CE34h]

我无法理解这里发生的情况的行。我尝试在互联网上搜索，但找不到任何有用的东西。有人对问题的原因或如何解决有任何建议吗？

编辑

我忘记添加我正在使用 Visual Studio 2008 并编译成 .NET 3.5 的信息。 所有更新均已安装。

在 C# 中编辑

整个方法

        private void nativeDocumentServiceWrapper_PostInvokeEvents(object sender, WebServiceInvokeEventArgs e)
        {
            Exception exception = e.Exception;
            if (exception == null)
            {
                _invokeRetries = 0;
                return;
            }

            string errorCodeString = ErrorHandler.GetErrorCodeString(exception);
            int errorCode;
            if (int.TryParse(errorCodeString, out errorCode))
            {
                e.Exception = new VaultException(errorCode, exception);
            }

            Int32 errorCode32 = errorCode;
            Int32 errorTimeout = 300;

            if (errorCode32.Equals(errorTimeout) == false)
            {
                System.Console.Out.WriteLine("aaa");
                return;
            }

            Trace.TraceWarning("Invoke failed (count: {4}) {0}.{1} #{2} error '{3}'", _moduleName, e.MethodName, _id, errorCodeString, _invokeRetries + 1);

            if (_invokeRetries > 0)
            {
                //int errorCode;
                if (int.TryParse(errorCodeString, out errorCode))
                {
                    //throw new VaultException(errorCode, exception);
                    e.Exception = new VaultException(errorCode, exception);
                }
                return;
            }

            e.Exception = null;

            // we ran into error 300 or 319
            // the solution is to log in again and re-run the command

            tryReloginAndInvokeVaultMethodAgain(e);
        }

并反汇编：

    34:             private void nativeDocumentServiceWrapper_PostInvokeEvents(object sender, WebServiceInvokeEventArgs e)
    35:             {
00000000  push        ebp  
00000001  mov         ebp,esp 
00000003  push        edi  
00000004  push        esi  
00000005  push        ebx  
00000006  sub         esp,84h 
0000000c  mov         esi,ecx 
0000000e  lea         edi,[ebp-54h] 
00000011  mov         ecx,12h 
00000016  xor         eax,eax 
00000018  rep stos    dword ptr es:[edi] 
0000001a  mov         ecx,esi 
0000001c  xor         eax,eax 
0000001e  mov         dword ptr [ebp-1Ch],eax 
00000021  mov         dword ptr [ebp-3Ch],ecx 
00000024  mov         dword ptr [ebp-40h],edx 
00000027  cmp         dword ptr ds:[01AD2DD8h],0 
0000002e  je          00000035 
00000030  call        6AB8A719 
00000035  mov         dword ptr [ebp-48h],0 
0000003c  xor         edx,edx 
0000003e  mov         dword ptr [ebp-5Ch],edx 
00000041  xor         edx,edx 
00000043  mov         dword ptr [ebp-44h],edx 
00000046  xor         edx,edx 
00000048  mov         dword ptr [ebp-4Ch],edx 
0000004b  xor         edx,edx 
0000004d  mov         dword ptr [ebp-58h],edx 
00000050  nop              
    36:                 Exception exception = e.Exception;
00000051  mov         eax,dword ptr [ebp+8] 
00000054  mov         eax,dword ptr [eax+4] 
00000057  mov         dword ptr [ebp-44h],eax 
    37:                 if (exception == null)
0000005a  cmp         dword ptr [ebp-44h],0 
0000005e  setne       al   
00000061  movzx       eax,al 
00000064  mov         dword ptr [ebp-48h],eax 
00000067  cmp         dword ptr [ebp-48h],0 
0000006b  jne         0000007F 
    38:                 {
0000006d  nop              
    39:                     _invokeRetries = 0;
0000006e  mov         eax,dword ptr [ebp-3Ch] 
00000071  xor         edx,edx 
00000073  mov         dword ptr [eax+00000088h],edx 
    40:                     return;
00000079  nop              
0000007a  jmp         00000287 
    41:                 }
    42: 
    43:                 string errorCodeString = ErrorHandler.GetErrorCodeString(exception);
0000007f  mov         ecx,dword ptr [ebp-44h] 
00000082  call        FF0827F0 
00000087  mov         dword ptr [ebp-60h],eax 
0000008a  mov         eax,dword ptr [ebp-60h] 
0000008d  mov         dword ptr [ebp-4Ch],eax 
    44:                 int errorCode;
    45:                 if (int.TryParse(errorCodeString, out errorCode))
00000090  lea         edx,[ebp-50h] 
00000093  mov         ecx,dword ptr [ebp-4Ch] 
00000096  call        694B44A8 
0000009b  mov         dword ptr [ebp-64h],eax 
0000009e  cmp         dword ptr [ebp-64h],0 
000000a2  sete        al   
000000a5  movzx       eax,al 
000000a8  mov         dword ptr [ebp-48h],eax 
000000ab  cmp         dword ptr [ebp-48h],0 
000000af  jne         000000E5 
    46:                 {
000000b1  nop              
    47:                     e.Exception = new VaultException(errorCode, exception);
000000b2  mov         ecx,5482E0Ch 
000000b7  call        FA68D364 
000000bc  mov         dword ptr [ebp+FFFFFF78h],eax 
000000c2  push        dword ptr [ebp-44h] 
000000c5  mov         edx,dword ptr [ebp-50h] 
000000c8  mov         ecx,dword ptr [ebp+FFFFFF78h] 
000000ce  call        FF07FCB0 
000000d3  mov         edx,dword ptr [ebp+8] 
000000d6  mov         eax,dword ptr [ebp+FFFFFF78h] 
000000dc  lea         edx,[edx+4] 
000000df  call        6A90E288 
    48:                 }
000000e4  nop              
    49: 
    50:                 Int32 errorCode32 = errorCode;
000000e5  mov         eax,dword ptr [ebp-50h] 
000000e8  mov         dword ptr [ebp-54h],eax 
    51:                 Int32 errorTimeout = 300;
000000eb  mov         dword ptr [ebp-58h],12Ch 
    52: 
    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }
    58: 
    59:                 Trace.TraceWarning("Invoke failed (count: {4}) {0}.{1} #{2} error '{3}'", _moduleName, e.MethodName, _id, errorCodeString, _invokeRetries + 1);
0000014f  mov         eax,dword ptr [ebp-70h] 
00000152  mov         dword ptr [ebp-5Ch],eax 
00000155  mov         eax,dword ptr [ebp-3Ch] 
00000158  push        dword ptr [eax+00000080h] 
0000015e  mov         ecx,dword ptr [ebp-5Ch] 
00000161  xor         edx,edx 
00000163  call        6A914654 
00000168  mov         eax,dword ptr [ebp+8] 
0000016b  push        dword ptr [eax+8] 
0000016e  mov         ecx,dword ptr [ebp-5Ch] 
00000171  mov         edx,1 
00000176  call        6A914654 
0000017b  mov         ecx,6F052DA0h 
00000180  call        FA68D364 
00000185  mov         dword ptr [ebp-74h],eax 
00000188  mov         eax,dword ptr [ebp-5Ch] 
0000018b  mov         dword ptr [ebp+FFFFFF74h],eax 
00000191  mov         eax,dword ptr [ebp-3Ch] 
00000194  mov         eax,dword ptr [eax+00000084h] 
0000019a  mov         edx,dword ptr [ebp-74h] 
0000019d  mov         dword ptr [edx+4],eax 
000001a0  mov         eax,dword ptr [ebp-74h] 
000001a3  push        eax  
000001a4  mov         ecx,dword ptr [ebp+FFFFFF74h] 
000001aa  mov         edx,2 
000001af  call        6A914654 
000001b4  push        dword ptr [ebp-4Ch] 
000001b7  mov         ecx,dword ptr [ebp-5Ch] 
000001ba  mov         edx,3 
000001bf  call        6A914654 
000001c4  mov         ecx,6F052DA0h 
000001c9  call        FA68D364 
000001ce  mov         dword ptr [ebp-78h],eax 
000001d1  mov         eax,dword ptr [ebp-5Ch] 
000001d4  mov         dword ptr [ebp+FFFFFF70h],eax 
000001da  mov         eax,dword ptr [ebp-3Ch] 
000001dd  mov         eax,dword ptr [eax+00000088h] 
000001e3  inc         eax  
000001e4  mov         edx,dword ptr [ebp-78h] 
000001e7  mov         dword ptr [edx+4],eax 
000001ea  mov         eax,dword ptr [ebp-78h] 
000001ed  push        eax  
000001ee  mov         ecx,dword ptr [ebp+FFFFFF70h] 
000001f4  mov         edx,4 
000001f9  call        6A914654 
000001fe  mov         edx,dword ptr [ebp-5Ch] 
00000201  mov         ecx,dword ptr [ebp-6Ch] 
00000204  call        69039D88 
00000209  nop              
    60: 
    61:                 if (_invokeRetries > 0)
0000020a  mov         eax,dword ptr [ebp-3Ch] 
0000020d  cmp         dword ptr [eax+00000088h],0 
00000214  setle       al   
00000217  movzx       eax,al 
0000021a  mov         dword ptr [ebp-48h],eax 
0000021d  cmp         dword ptr [ebp-48h],0 
00000221  jne         00000273 
    62:                 {
00000223  nop              
    63:                     //int errorCode;
    64:                     if (int.TryParse(errorCodeString, out errorCode))
00000224  lea         edx,[ebp-50h] 
00000227  mov         ecx,dword ptr [ebp-4Ch] 
0000022a  call        694B44A8 
0000022f  mov         dword ptr [ebp-7Ch],eax 
00000232  cmp         dword ptr [ebp-7Ch],0 
00000236  sete        al   
00000239  movzx       eax,al 
0000023c  mov         dword ptr [ebp-48h],eax 
0000023f  cmp         dword ptr [ebp-48h],0 
00000243  jne         00000270 
    65:                     {
00000245  nop              
    66:                         //throw new VaultException(errorCode, exception);
    67:                         e.Exception = new VaultException(errorCode, exception);
00000246  mov         ecx,5482E0Ch 
0000024b  call        FA68D364 
00000250  mov         dword ptr [ebp-80h],eax 
00000253  push        dword ptr [ebp-44h] 
00000256  mov         edx,dword ptr [ebp-50h] 
00000259  mov         ecx,dword ptr [ebp-80h] 
0000025c  call        FF07FCB0 
00000261  mov         edx,dword ptr [ebp+8] 
00000264  mov         eax,dword ptr [ebp-80h] 
00000267  lea         edx,[edx+4] 
0000026a  call        6A90E288 
    68:                     }
0000026f  nop              
    69:                     return;
00000270  nop              
00000271  jmp         00000287 
    70:                 }
    71: 
    72:                 e.Exception = null;
00000273  mov         eax,dword ptr [ebp+8] 
00000276  xor         edx,edx 
00000278  mov         dword ptr [eax+4],edx 
    73: 
    74:                 // we ran into error 300 or 319
    75:                 // the solution is to log in again and re-run the command
    76: 
    77:                 tryReloginAndInvokeVaultMethodAgain(e);
0000027b  mov         edx,dword ptr [ebp+8] 
0000027e  mov         ecx,dword ptr [ebp-3Ch] 
00000281  call        FF0876C0 
00000286  nop              
    78:             }
原文

I encounter really weird problem on which I stuck.

I am working on some class library which connects to webservices. The library is used by desktop applications.

In the code I have now:

Int32 errorCode32 = errorCode;
Int32 errorTimeout = 300;

if (errorCode32.Equals(errorTimeout) == false)
{
    System.Console.Out.WriteLine("aaa");
    return;
}

where errorCode equals to 300. So at the first glance it is visible, that if errorCode == 300 than the code inside the if statement should not be executed because it is defined to be executed only when errorCode is not equal to 300.

Until now everything is clear, but now the whole fun starts.

Application is working and the method with above code snippet is executed. errorCode is equal to 300, that is expected result is that the application will not execute any code inside if statement because whole statement is false. But in reality application goes inside "if" and immediately skips to the "return" statement. System.Console.Out... is never executed. If I will replace clean "return" statement with "throw new SomeException()"

Int32 errorCode32 = errorCode;
Int32 errorTimeout = 300;

if (errorCode32.Equals(errorTimeout) == false)
{
    System.Console.Out.WriteLine("aaa");
    throw new SomeException();
}

I will get the same result. Application goes into if statement (note: [errorCode32.Equals(errorTimeout) == false] is false in my case), don't execute Console.Out... but throws SomeException.

I rebuilded everything several times, deleted all binaries, I even deleted whole project from disk and retrieved it again from repository to clean folder.

I was so confused that I even disassembled the code to see what happens (even if I am not an expert in assembler). But results are strange for me.

Disassembled code follows:

    50:                 Int32 errorCode32 = errorCode;
000000e5  mov         eax,dword ptr [ebp-50h] 
000000e8  mov         dword ptr [ebp-54h],eax 
    51:                 Int32 errorTimeout = 300;
000000eb  mov         dword ptr [ebp-58h],12Ch 
    52: 
    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }

when I am debugging instructions I can understand what happens until the line:

00000104  mov         dword ptr [ebp-48h],eax

I expect that value stored in eax will be copied to location "dword ptr [ebp-48h]" and application wiil go to next line (00000107). But this doesn't happen. When I am trying to step over line 00000104, application immediately jumps to line

00000134  mov         eax,dword ptr ds:[0302CE34h]

I cannot understand what happens here. I tried to search over internet but I couldn't find anything useful. Does anybody have any suggestions what could be the reason of the problem or how to solve that?

Edit

I forgot to put information that I am using Visual Studio 2008 and compiling into .NET 3.5.
All updates are installed.

Edit

Entire method in C#

        private void nativeDocumentServiceWrapper_PostInvokeEvents(object sender, WebServiceInvokeEventArgs e)
        {
            Exception exception = e.Exception;
            if (exception == null)
            {
                _invokeRetries = 0;
                return;
            }

            string errorCodeString = ErrorHandler.GetErrorCodeString(exception);
            int errorCode;
            if (int.TryParse(errorCodeString, out errorCode))
            {
                e.Exception = new VaultException(errorCode, exception);
            }

            Int32 errorCode32 = errorCode;
            Int32 errorTimeout = 300;

            if (errorCode32.Equals(errorTimeout) == false)
            {
                System.Console.Out.WriteLine("aaa");
                return;
            }

            Trace.TraceWarning("Invoke failed (count: {4}) {0}.{1} #{2} error '{3}'", _moduleName, e.MethodName, _id, errorCodeString, _invokeRetries + 1);

            if (_invokeRetries > 0)
            {
                //int errorCode;
                if (int.TryParse(errorCodeString, out errorCode))
                {
                    //throw new VaultException(errorCode, exception);
                    e.Exception = new VaultException(errorCode, exception);
                }
                return;
            }

            e.Exception = null;

            // we ran into error 300 or 319
            // the solution is to log in again and re-run the command

            tryReloginAndInvokeVaultMethodAgain(e);
        }

and disassembled:

    34:             private void nativeDocumentServiceWrapper_PostInvokeEvents(object sender, WebServiceInvokeEventArgs e)
    35:             {
00000000  push        ebp  
00000001  mov         ebp,esp 
00000003  push        edi  
00000004  push        esi  
00000005  push        ebx  
00000006  sub         esp,84h 
0000000c  mov         esi,ecx 
0000000e  lea         edi,[ebp-54h] 
00000011  mov         ecx,12h 
00000016  xor         eax,eax 
00000018  rep stos    dword ptr es:[edi] 
0000001a  mov         ecx,esi 
0000001c  xor         eax,eax 
0000001e  mov         dword ptr [ebp-1Ch],eax 
00000021  mov         dword ptr [ebp-3Ch],ecx 
00000024  mov         dword ptr [ebp-40h],edx 
00000027  cmp         dword ptr ds:[01AD2DD8h],0 
0000002e  je          00000035 
00000030  call        6AB8A719 
00000035  mov         dword ptr [ebp-48h],0 
0000003c  xor         edx,edx 
0000003e  mov         dword ptr [ebp-5Ch],edx 
00000041  xor         edx,edx 
00000043  mov         dword ptr [ebp-44h],edx 
00000046  xor         edx,edx 
00000048  mov         dword ptr [ebp-4Ch],edx 
0000004b  xor         edx,edx 
0000004d  mov         dword ptr [ebp-58h],edx 
00000050  nop              
    36:                 Exception exception = e.Exception;
00000051  mov         eax,dword ptr [ebp+8] 
00000054  mov         eax,dword ptr [eax+4] 
00000057  mov         dword ptr [ebp-44h],eax 
    37:                 if (exception == null)
0000005a  cmp         dword ptr [ebp-44h],0 
0000005e  setne       al   
00000061  movzx       eax,al 
00000064  mov         dword ptr [ebp-48h],eax 
00000067  cmp         dword ptr [ebp-48h],0 
0000006b  jne         0000007F 
    38:                 {
0000006d  nop              
    39:                     _invokeRetries = 0;
0000006e  mov         eax,dword ptr [ebp-3Ch] 
00000071  xor         edx,edx 
00000073  mov         dword ptr [eax+00000088h],edx 
    40:                     return;
00000079  nop              
0000007a  jmp         00000287 
    41:                 }
    42: 
    43:                 string errorCodeString = ErrorHandler.GetErrorCodeString(exception);
0000007f  mov         ecx,dword ptr [ebp-44h] 
00000082  call        FF0827F0 
00000087  mov         dword ptr [ebp-60h],eax 
0000008a  mov         eax,dword ptr [ebp-60h] 
0000008d  mov         dword ptr [ebp-4Ch],eax 
    44:                 int errorCode;
    45:                 if (int.TryParse(errorCodeString, out errorCode))
00000090  lea         edx,[ebp-50h] 
00000093  mov         ecx,dword ptr [ebp-4Ch] 
00000096  call        694B44A8 
0000009b  mov         dword ptr [ebp-64h],eax 
0000009e  cmp         dword ptr [ebp-64h],0 
000000a2  sete        al   
000000a5  movzx       eax,al 
000000a8  mov         dword ptr [ebp-48h],eax 
000000ab  cmp         dword ptr [ebp-48h],0 
000000af  jne         000000E5 
    46:                 {
000000b1  nop              
    47:                     e.Exception = new VaultException(errorCode, exception);
000000b2  mov         ecx,5482E0Ch 
000000b7  call        FA68D364 
000000bc  mov         dword ptr [ebp+FFFFFF78h],eax 
000000c2  push        dword ptr [ebp-44h] 
000000c5  mov         edx,dword ptr [ebp-50h] 
000000c8  mov         ecx,dword ptr [ebp+FFFFFF78h] 
000000ce  call        FF07FCB0 
000000d3  mov         edx,dword ptr [ebp+8] 
000000d6  mov         eax,dword ptr [ebp+FFFFFF78h] 
000000dc  lea         edx,[edx+4] 
000000df  call        6A90E288 
    48:                 }
000000e4  nop              
    49: 
    50:                 Int32 errorCode32 = errorCode;
000000e5  mov         eax,dword ptr [ebp-50h] 
000000e8  mov         dword ptr [ebp-54h],eax 
    51:                 Int32 errorTimeout = 300;
000000eb  mov         dword ptr [ebp-58h],12Ch 
    52: 
    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }
    58: 
    59:                 Trace.TraceWarning("Invoke failed (count: {4}) {0}.{1} #{2} error '{3}'", _moduleName, e.MethodName, _id, errorCodeString, _invokeRetries + 1);
0000014f  mov         eax,dword ptr [ebp-70h] 
00000152  mov         dword ptr [ebp-5Ch],eax 
00000155  mov         eax,dword ptr [ebp-3Ch] 
00000158  push        dword ptr [eax+00000080h] 
0000015e  mov         ecx,dword ptr [ebp-5Ch] 
00000161  xor         edx,edx 
00000163  call        6A914654 
00000168  mov         eax,dword ptr [ebp+8] 
0000016b  push        dword ptr [eax+8] 
0000016e  mov         ecx,dword ptr [ebp-5Ch] 
00000171  mov         edx,1 
00000176  call        6A914654 
0000017b  mov         ecx,6F052DA0h 
00000180  call        FA68D364 
00000185  mov         dword ptr [ebp-74h],eax 
00000188  mov         eax,dword ptr [ebp-5Ch] 
0000018b  mov         dword ptr [ebp+FFFFFF74h],eax 
00000191  mov         eax,dword ptr [ebp-3Ch] 
00000194  mov         eax,dword ptr [eax+00000084h] 
0000019a  mov         edx,dword ptr [ebp-74h] 
0000019d  mov         dword ptr [edx+4],eax 
000001a0  mov         eax,dword ptr [ebp-74h] 
000001a3  push        eax  
000001a4  mov         ecx,dword ptr [ebp+FFFFFF74h] 
000001aa  mov         edx,2 
000001af  call        6A914654 
000001b4  push        dword ptr [ebp-4Ch] 
000001b7  mov         ecx,dword ptr [ebp-5Ch] 
000001ba  mov         edx,3 
000001bf  call        6A914654 
000001c4  mov         ecx,6F052DA0h 
000001c9  call        FA68D364 
000001ce  mov         dword ptr [ebp-78h],eax 
000001d1  mov         eax,dword ptr [ebp-5Ch] 
000001d4  mov         dword ptr [ebp+FFFFFF70h],eax 
000001da  mov         eax,dword ptr [ebp-3Ch] 
000001dd  mov         eax,dword ptr [eax+00000088h] 
000001e3  inc         eax  
000001e4  mov         edx,dword ptr [ebp-78h] 
000001e7  mov         dword ptr [edx+4],eax 
000001ea  mov         eax,dword ptr [ebp-78h] 
000001ed  push        eax  
000001ee  mov         ecx,dword ptr [ebp+FFFFFF70h] 
000001f4  mov         edx,4 
000001f9  call        6A914654 
000001fe  mov         edx,dword ptr [ebp-5Ch] 
00000201  mov         ecx,dword ptr [ebp-6Ch] 
00000204  call        69039D88 
00000209  nop              
    60: 
    61:                 if (_invokeRetries > 0)
0000020a  mov         eax,dword ptr [ebp-3Ch] 
0000020d  cmp         dword ptr [eax+00000088h],0 
00000214  setle       al   
00000217  movzx       eax,al 
0000021a  mov         dword ptr [ebp-48h],eax 
0000021d  cmp         dword ptr [ebp-48h],0 
00000221  jne         00000273 
    62:                 {
00000223  nop              
    63:                     //int errorCode;
    64:                     if (int.TryParse(errorCodeString, out errorCode))
00000224  lea         edx,[ebp-50h] 
00000227  mov         ecx,dword ptr [ebp-4Ch] 
0000022a  call        694B44A8 
0000022f  mov         dword ptr [ebp-7Ch],eax 
00000232  cmp         dword ptr [ebp-7Ch],0 
00000236  sete        al   
00000239  movzx       eax,al 
0000023c  mov         dword ptr [ebp-48h],eax 
0000023f  cmp         dword ptr [ebp-48h],0 
00000243  jne         00000270 
    65:                     {
00000245  nop              
    66:                         //throw new VaultException(errorCode, exception);
    67:                         e.Exception = new VaultException(errorCode, exception);
00000246  mov         ecx,5482E0Ch 
0000024b  call        FA68D364 
00000250  mov         dword ptr [ebp-80h],eax 
00000253  push        dword ptr [ebp-44h] 
00000256  mov         edx,dword ptr [ebp-50h] 
00000259  mov         ecx,dword ptr [ebp-80h] 
0000025c  call        FF07FCB0 
00000261  mov         edx,dword ptr [ebp+8] 
00000264  mov         eax,dword ptr [ebp-80h] 
00000267  lea         edx,[edx+4] 
0000026a  call        6A90E288 
    68:                     }
0000026f  nop              
    69:                     return;
00000270  nop              
00000271  jmp         00000287 
    70:                 }
    71: 
    72:                 e.Exception = null;
00000273  mov         eax,dword ptr [ebp+8] 
00000276  xor         edx,edx 
00000278  mov         dword ptr [eax+4],edx 
    73: 
    74:                 // we ran into error 300 or 319
    75:                 // the solution is to log in again and re-run the command
    76: 
    77:                 tryReloginAndInvokeVaultMethodAgain(e);
0000027b  mov         edx,dword ptr [ebp+8] 
0000027e  mov         ecx,dword ptr [ebp-3Ch] 
00000281  call        FF0876C0 
00000286  nop              
    78:             }

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苏别ゝ 2025-01-02 18:28:50

您启用了优化，并且编译器将 if 语句内的 return 语句与函数末尾的语句组合在一起。两者具有相同的地址，调试器无法分辨要突出显示哪一行源代码，因为两者匹配。

没有任何问题。但如果您希望单步执行调试器正常工作，则必须禁用优化。

这只是优化器可以用来迷惑调试器的几件事之一。其他可能性是重新排序不具有数据依赖性的语句（以优化管道），甚至将语句分开并在其间放置另一个语句。

You have optimization enabled, and the compiler combined the return statement inside the if statement with the one at the end of the function. The two have the same address, the debugger can't tell which line of source code to highlight, because both match.

There's nothing wrong whatsoever. But if you want stepping through the debugger to work normally, you have to disable optimization.

This is only one of several things the optimizer can do to confuse the debugger. Other possibilities are reordering statements that don't have a data dependency (to optimize the pipeline), even splitting statements apart and putting another statement in between.

回复 原文
雨夜星沙 2025-01-02 18:28:50

我花了更多时间调查这个问题，并得出了一些结论，我想与大家分享，即使这意味着我必须承认我做出了一些错误的假设，并且我无法全面了解整个行为。

首先：我提供的代码旨在处理使用某些第三方库时的某些特定问题。这些库的未记录行为是，在某些情况下它会在某些条件下引发异常。最初的问题来自这样一个事实，即使我们“处理”错误情况，该库也会抛出异常

第二：调试时我发现以下情况：

1    if (someVariable)
2    {
3        someCode();
4        someOtherCode();
5        throw someExceptionPassedFromTheThirdPartyLibrary;
6    }
7    somethingElse();

调试器在第 1 行停止，someVariable 为 false，单步跳过，调试器在第 5 行等待。我做了第一个错误的假设 - 那就是我的异常是从这里抛出的。

第三：我开始尝试。 “someVariable”始终为 false，但有时调试器会从第 1 行跳到第 7 行，有时会从第 1 行跳到第 5 行。我决定使用反汇编程序。

第四：我无法理解反汇编代码的行为，它使我的想法固定下来，即 if 语句行为不正确。另外，我发现文章“http://stackoverflow.com/questions/6054987/if-statement-appears-to-be-evaluating-even-when-condition-evaluates-to-false”[确认的 JIT bug] 没有这次帮了我。

好吧，我认为在了解了一些额外的背景知识之后，是时候解释一下我的代码中到底发生了什么。

一般来说，在我的情况下，“if”语句的行为正确。当我更多地了解汇编器和现代处理器架构时，我明白了这一点。

    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }

偏移量 00000104-0000010b 处的指令执行已由处理器架构优化（可能发生跳转预测，或一些其他核心处理器优化）。因此，处理器不再调用三条指令，而是一步执行所有操作。因为 00000107 中应该比较的值不相等，所以处理器跳转到 00000134。此时我无法理解这里实际发生的情况，所以我假设它只是执行“return”指令。事实很简单 - “从 if 返回”指令并不像我那样位于 00000134，而是指令区域 - 在 0000012f，这只是简单的无条件跳转。

当我理解这一点时，我知道这段代码的行为是正确的。所以我再次转向C#，我发现了一些让我非常羞愧的东西。因为当我再次调试代码时，我发现它的行为是这样的：

1    if (someVariable)
2    {
3        someCode();
4        someOtherCode();
5        throw someExceptionPassedFromTheThirdPartyLibrary;
6    }
7    somethingElse();

断点在1，F10
当前行指示器位于 5，按 F10
当前行指示器位于 7，按 F10...，依此类推。

所以我知道调试器会执行最后一个“if”指令，但不会执行该指令。这是一个错误 - 但不在“if”处理中，而仅在 VS 调试器中。此外，该错误并不重要，因为它实际上只是演示，对调试的代码没有任何影响。

I spent more time investigating the problem and I have some conclusions which I would like to share, even if it means that I must to admit that I made several false assumptions and I was not able to get a big picture of whole behavior.

First: the code which I presented was intended to handle some particular problem when using some third party library. The undocumented behavior of those library was that in some situation it throws exception on some conditions. Original problem comes from the fact, that library throwed exception even if we "handled" error situation

Second: when debugging I found following situation:

1    if (someVariable)
2    {
3        someCode();
4        someOtherCode();
5        throw someExceptionPassedFromTheThirdPartyLibrary;
6    }
7    somethingElse();

debugger stopped at line 1, someVariable is false, step over, debugger is waiting at line 5. And here I made a first false assumption - that is that my exception is thrown from here.

Third: I started to experiment. "someVariable" was always false, but sometimes debugger skipped from line 1 to 7 and sometimes from 1 to 5. I decided to use disassembler.

Fourth: I couldn't understand behavior of disassembled code and it fixed my mind on idea, that if statement behaves incorrectly. Additionally I found article "http://stackoverflow.com/questions/6054987/if-statement-appears-to-be-evaluating-even-when-condition-evaluates-to-false" [confirmed JIT bug] which didn't helped me this time.

Ok I think that after some additional background it is time to explain what really happened in my code.

In general in my situation "if" statement behaved correctly. I understood that when I learned a little bit more regarding assembler and moder processor architecture.

    53:                 if (errorCode32.Equals(errorTimeout) == false)
000000f2  lea         ecx,[ebp-54h] 
000000f5  mov         edx,dword ptr [ebp-58h] 
000000f8  call        699EB198 
000000fd  mov         dword ptr [ebp-68h],eax 
00000100  movzx       eax,byte ptr [ebp-68h] 
00000104  mov         dword ptr [ebp-48h],eax 
00000107  cmp         dword ptr [ebp-48h],0 
0000010b  jne         00000134 
    54:                 {
0000010d  nop              
    55:                     System.Console.Out.WriteLine("aaa");
0000010e  call        69538768 
00000113  mov         dword ptr [ebp+FFFFFF7Ch],eax 
00000119  mov         edx,dword ptr ds:[0302CE30h] 
0000011f  mov         ecx,dword ptr [ebp+FFFFFF7Ch] 
00000125  mov         eax,dword ptr [ecx] 
00000127  call        dword ptr [eax+000000D8h] 
0000012d  nop              
    56:                     return;
0000012e  nop              
0000012f  jmp         00000287 
00000134  mov         eax,dword ptr ds:[0302CE34h] 
0000013a  mov         dword ptr [ebp-6Ch],eax 
0000013d  mov         edx,5 
00000142  mov         ecx,6EDE3FBEh 
00000147  call        FA68D488 
0000014c  mov         dword ptr [ebp-70h],eax 
    57:                 }

Execution of instructions at offsets 00000104-0000010b was optimized by processor architecture (perhaps jump predicting takes place, or some other core processor optimizations). So instead of calling three instructions, processor executed everything in one step. Because values which should be compared in 00000107 were not equal, so processor jumped to 00000134. At this point I couldn't understand what actually happens here, so I assumed that it just executes "return" instruction. The truth is simple - "return from if" instruction is not at 00000134 as I though, but instruction arealier - at 0000012f and this is just simple unconditional jump.

When I understood this I knew that this code behaves corretly. So I moved again to C# and I found something which made me really ashamed. Because when I debugged the code once again I found that it behaves this way:

1    if (someVariable)
2    {
3        someCode();
4        someOtherCode();
5        throw someExceptionPassedFromTheThirdPartyLibrary;
6    }
7    somethingElse();

breakpoint at 1, F10
current line indicator at 5, press F10
current line indicator at 7, press F10... and so on.

So I understood that the debugger steps inside last "if" instruction, but doesn't execute that. It is a bug - but not in "if" handling, and only in VS debugger. Additionally the bug is not critical since it is actually just presentation and doesn't have any influence on the debugged code.

回复 原文
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