WINDBG:查看未命名命名空间中变量的值

Question

当您进入Windbg时，是否存在某种方法来查看未命名命名空间中的变量的值？我将变量定位如下：

0:000> x mod!ns::*myvar*
70f7afc6          mod!ns::`anonymous namespace'::`dynamic initializer for 'myvar'' (void)
717bb799          mod!ns::`anonymous namespace'::`dynamic atexit destructor for 'myvar'' (void)
71a00718          mod!ns::`anonymous namespace'::myvar = <no type information>

myvar基本上是一个std::map，并且有一个调试器可视化工具(natvis)可供它使用，这样?? myvar就应该显示一些有用的东西。但是，由于这个匿名命名空间处于中间位置，我似乎无法找到正确的语法来显示myvar中的值。

有什么想法吗？

Answer 1

默认情况下，visual studio调试器下的监视窗口中不支持匿名命名空间，直到最近的7/17。

从历史上看，风车在实现这些花哨显示器方面落后了一两英里。

那就是说你的名字空间嵌套了吗？

我想是的，因为在模块mod! ns ::之后有一个ns

如果情况不是这样，x mymap将产生一个可点击的dml链接，它将正确显示类型，如果它是嵌套的，windbg会吐出，没有可用的类型信息。

在这种情况下，可以使用指针(如mod!std::map..........xxx... )将它们转换为实际类型。

下面是在windbg下编译和执行的人为的源代码，它演示了一些可能性。

第一个文件的源，它包含、未命名的ns和命名的嵌套未命名ns，还引用了另一个包含匿名命名空间的文件。

#include "anonall.h"
namespace {
    map<char, const char*> mymap;
    const char *Greek_Alphabets[ALLOCSIZ] = { "Alp","Bet","Gam","Del","Eps" };
}
namespace ns {
    namespace {
        map<char, const char*> mymap;
        const char *Greek_Alphabets[ALLOCSIZ]={ 
        "Alpha","Beta","Gamma","Delta","Epsilon" };
    }
}
void anonnsptwo(void);
void anonnsptre(void) {
    cout << "\nfrom Anonymous NS Map in " << __FILE__ << " " << __LINE__ << "\n\n";
    for (int i = 0; i < ALLOCSIZ; i++) {
        mymap.insert(pair<char, const char*>(char('M' + i), Greek_Alphabets[i]));
    }
    map<char, const char*>::iterator iter = mymap.begin();
    for (iter; iter != mymap.end(); iter++)
        cout << iter->first << " = " << iter->second << "\n";
}
int main(void) {
    anonnsptre();
    cout << "\nfrom Anonymous NS Map in " << __FILE__ << " " << __LINE__ << "\n\n";
    for (int i = 0; i < ALLOCSIZ; i++) {
        ns::mymap.insert(pair<char, const char*>(char('A'+i),ns::Greek_Alphabets[i]));
    }
    map<char, const char*>::iterator iter = ns::mymap.begin();
    for (iter; iter != ns::mymap.end(); iter++)
        cout << iter->first << " = " << iter->second << "\n";
    anonnsptwo();
    return 0;
}

第一个文件引用的第二个文件的来源

#include "anonall.h"
namespace ns {
    namespace {
        map<char, const char*> mymap;
        const char *Greek_Alphabets[ALLOCSIZ]={"Zeta","Eta","Theta","Iota","Kappa"};
    }
}
void anonnsptwo(void) {
    cout << "\nfrom Anonymous Namespace Map in " << __FILE__ << "\n\n";
    for (int i = 0; i < ALLOCSIZ; i++) {
    ns::mymap.insert(pair<char, const char*>(char('Z'-i),ns::Greek_Alphabets[i]));
    }
    map<char, const char*>::iterator iter = ns::mymap.begin();
    for (iter; iter != ns::mymap.end(); iter++)
        cout << iter->first << " = " << iter->second << "\n";
}

常见的头文件内容

#pragma once
#include <iostream>
#include <map>
#define ALLOCSIZ 5
using namespace std;

编译并链接vs community 2017 (15.6.4) cmd提示符

:\>echo off

ls
anonall.h  anonone.cpp  anontwo.cpp

cl /Zi /W4 /analyze /EHsc /Od /nologo anonone.cpp anontwo.cpp /link /release /nologo

anonone.cpp
anontwo.cpp
Compiling...
Generating Code...

ls
anonall.h                       anonone.obj                     anontwo.obj
anonone.cpp                     anonone.pdb                     vc140.pdb
anonone.exe                     anontwo.cpp
anonone.nativecodeanalysis.xml  anontwo.nativecodeanalysis.xml

执行二进制文件

anonone.exe
from Anonymous NS Map in anonone.cpp 15

M = Alp
N = Bet
O = Gam
P = Del
Q = Eps

from Anonymous NS Map in anonone.cpp 25

A = Alpha
B = Beta
C = Gamma
D = Delta
E = Epsilon

from Anonymous Namespace Map in anontwo.cpp

V = Kappa
W = Iota
X = Theta
Y = Eta
Z = Zeta

使用cdb只显示结果而不需要用户干预。

如果使用windbg而不是cdb，则x*!*mymap的结果将是可点击的链接。

请注意大小=5，并注意其他两个没有类型信息的匿名mymap

(关于如何打印这些地图的问题如下所示)

设置第一个文件返回的断点(程序结束)

grep -in ret.* anonone.cpp

33 :返回0; <<行号为33

启用没有信息的行，在src行上设置条件延迟中断，并在命中该中断时，打印x命令的结果并退出

>cdb -c ".lines;bu anonone.cpp:33 \"x **mymap*\\；g；q‘anonone.exe e

cdb -c ".lines;bu `anonone.cpp:33` \"x *!*mymap*\";g;q" anonone.exe

Microsoft (R) Windows Debugger Version 10.0.16299.15 X86

0:000> cdb: Reading initial command '.lines;bu `anonone.cpp:33` "x *!*mymap*";g;q'

snipp======================

0118b938          anonone!mymap = { size=0x5 }
01175198          anonone!mymap$initializer$ = 0x01101040
011742c0          anonone!`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
01101040          anonone!`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
011742e0          anonone!ns::`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
011742d0          anonone!ns::`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
01101080          anonone!ns::`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
01101060          anonone!ns::`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
0118b930          anonone!ns::`anonymous namespace'::mymap = <no type information>
0118b960          anonone!ns::`anonymous namespace'::mymap = <no type information>

quit:

现在可以将mymap @ 0x0118b960和0x0118b930的地址转换为std::map。

(请执行x anonone!std::map点击选项卡查找类型信息，使其成为指针并粘贴地址并使用dx表达式计算器获取显示)

这类似于dx ( anonone!std:map......xx..yy..zz *) 0x0118b960

ntdll!LdrpDoDebuggerBreak+0x2c:
771d05a6 cc              int     3
Processing initial command '$$>a< displayanon.txt'
0:000> $$>a< displayanon.txt
ModLoad: 6b450000 6b453000   C:\Windows\system32\api-ms-win-core-synch-l1-2-0.DLL
00d6b938          anonone!mymap = { size=0x5 }
00d55198          anonone!mymap$initializer$ = 0x00ce1040
00d542c0          anonone!`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
00ce1040          anonone!`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
00d542e0          anonone!ns::`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
00d542d0          anonone!ns::`anonymous namespace'::`dynamic atexit destructor for 'mymap'' (void)
00ce1080          anonone!ns::`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
00ce1060          anonone!ns::`anonymous namespace'::`dynamic initializer for 'mymap'' (void)
00d6b930          anonone!ns::`anonymous namespace'::mymap = <no type information>
00d6b960          anonone!ns::`anonymous namespace'::mymap = <no type information>


this is the type which you can get by using x {mod}!{std::map {wildcard}}

class std::map<char,char const *,std::less<char>,std::allocator<std::pair<char const ,char const *> > >
   +0x000 _Mypair          : 
mymap                 : { size=0x5 } 
snipped
    [0x0]            : 77 'M', "Alp" [Type: 
    [0x1]            : 78 'N', "Bet" [Type: 
    [0x2]            : 79 'O', "Gam" [Type: 
    [0x3]            : 80 'P', "Del" [Type: 
    [0x4]            : 81 'Q', "Eps" [Type: 

0:000> dx ( std::map<char,char const *,std::less<char>,std::allocator<std::pair<char const ,char const *> > > *) 0x00d6b930
( std::map<char,char const *,std::less<char>,std::allocator<std::pair<char const ,char const *> > > *) 0x00d6b930 
snipped
    [0x1]            : 65 'A', "Alpha" [Type:
    [0x2]            : 66 'B', "Beta" [Type:
    [0x3]            : 67 'C', "Gamma" [Type:
    [0x4]            : 68 'D', "Delta" [Type:
    [0x5]            : 69 'E', "Epsilon" [Type:

0:000> dx ( std::map<char,char const *,std::less<char>,std::allocator<std::pair<char const ,char const *> > > *) 0x00d6b960
( std::map<char,char const *,std::less<char>,std::allocator<std::pair<char const ,char const *> > > *) 0x00d6b960 
snipped
    [0x1]            : 86 'V', "Kappa" [Type: std::pair<char const ,char const *>]
    [0x2]            : 87 'W', "Iota" [Type: std::pair<char const ,char const *>]
    [0x3]            : 88 'X', "Theta" [Type: std::pair<char const ,char const *>]
    [0x4]            : 89 'Y', "Eta" [Type: std::pair<char const ,char const *>]
    [0x5]            : 90 'Z', "Zeta" [Type: std::pair<char const ,char const *>]