Debugging managed app with SOS - the start-优快云博客

本文介绍了使用Windbg调试托管代码的基本步骤与技巧。首先通过.loadby加载sos扩展，并提供了一个巧妙的方法来解决启动应用程序时遇到的问题。接着，通过演示!ip2md、!dumpmt等命令的使用，展示了如何查看已编译的方法。

Debugging managed code using windbg is always a headache to me and I kind of avoid doing that by using Visual Studio. It becomes a shame as time going since some people think I know it well. So I decided to learn from scratch - by debugging my own small app.

First thing is to load the sos extension. I like .loadby more than .load because it always load the correct version of sos extension. If you are debugging a dump it's easy since you can use ".loadby sos mscorwks". But .loadby doesn't work if you are starting the application with windbg since mscorwks has not been loaded yet. The workaround is a little bit tricky - type following in your debugger "sxe lh:mscorlib" then GO. This tells the debugger to stop execution when mscorlib is loaded, and of course mscorwks is loaded at that time. Afterwards you can load sos successfully using .loadby as above. Details you can refer to this excellent post.

Do play around !dumpmodule, !dumpmt and !dumpmd a little bit please. It took me a while to understand and remember what they are intended for given their name and their parameters' name are similar. :) We can tell which method has been jitted using !dumpmt. Powerful, isn't?

0:000> !ip2md @eip
MethodDesc: 007131e8
Method Name: TestException.TestFinally.Go2()
Class: 0071145c
MethodTable: 00713200
mdToken: 06000002
Module: 00712d8c
IsJitted: yes
m_CodeOrIL: 00de01c8

0:000> !dumpmt -md 00713200
EEClass: 0071145c
Module: 00712d8c
Name: TestException.TestFinally
mdToken: 02000002 (D:/Work/LearnCSharp/Exception/bin/Debug/Exception.exe)
BaseSize: 0xc
ComponentSize: 0x0
Number of IFaces in IFaceMap: 0
Slots in VTable: 8
--------------------------------------
MethodDesc Table
   Entry MethodDesc      JIT Name
79371278   7914b928   PreJIT System.Object.ToString()
7936b3b0   7914b930   PreJIT System.Object.Equals(System.Object)
7936b3d0   7914b948   PreJIT System.Object.GetHashCode()
793624d0   7914b950   PreJIT System.Object.Finalize()
0071c035   007131e0     NONE TestException.TestFinally.Go1()
00de01c8   007131e8      JIT TestException.TestFinally.Go2()
00de00f0   007131f0      JIT TestException.TestFinally.Go3()
00de00c0   007131f8      JIT TestException.TestFinally..ctor()