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cpp反汇编之protected

时间：2015-03-31 16:06:52      阅读：172      评论：0      收藏：0      [点我收藏+]

标签：反汇编   cpp   

protected关键字:

摘自MSDN

protected 关键字指定对 member-list 中的成员直到下一个访问说明符（public 或 private）或类定义的末尾的访问。 只能通过以下项使用声明为 protected 的类成员：

  • 最初声明这些成员的类的成员函数。

  • 最初声明这些成员的类的友元。

  • 使用公共或受保护访问（派生自最初声明这些成员的类）派生的类。

  • 也对受保护成员具有专用访问权限的以私有方式派生的直接类。

当以基类的名称开头时，protected 关键字指定基类的公共成员和保护成员是其派生类的保护成员。

保护成员不像 private 成员那样专用，private 成员仅对从中声明它们的类的成员可访问，但保护成员也不像 public 成员那样公开，public 成员在任何函数中均可访问。

也声明为 static 的保护成员对派生类的任何友元或成员函数均可访问。 也声明为 static 的保护成员对派生类中的友元或成员函数可访问，但只能通过指向派生类的指针、对派生类的引用或派生类的对象。

private：只能由1.该类中的函数、2.其友元函数访问。
不能被任何其他访问，该类的对象也不能访问。

protected：可以被1.该类中的函数、2.子类的函数、以及3.其友元函数访问。
但不能被该类的对象访问。

public：可以被1.该类中的函数、2.子类的函数、3.其友元函数访问，也可以由4.该类的对象访问。

下面分析一个例子 

#include <iostream>
using namespace std;

class Base {
    public:
    Base(int j): i(j)  {}
    virtual~Base() {}
 //   virtual 
		void func1() {
        i *= 10;
        func2(); //此处调用子类
    }
    int getValue() {
        return  i;
    }
    protected:
    virtual void func2() {
        i++;
    }
    protected:
    int i;
};
class Child: public Base {
    public:
    Child(int j): Base(j) {}
    void func1() {
        i *= 100;
        func2();
    }
    protected:
    void func2() {
        i += 2;
    }
};
int main() {
    Base * pb = new Child(1);
    pb->func1();//此处的this指针并未改变  只有一个对象
    cout << pb->getValue() << endl; 
	delete pb; 
}
输出: 12

下面是反汇编代码

1:    #include <iostream>
2:    using namespace std;
3:
4:    class Base {
5:        public:
6:        Base(int j): i(j)  {}
00401800   push        ebp
00401801   mov         ebp,esp
00401803   sub         esp,44h
00401806   push        ebx
00401807   push        esi
00401808   push        edi
00401809   push        ecx
0040180A   lea         edi,[ebp-44h]
0040180D   mov         ecx,11h
00401812   mov         eax,0CCCCCCCCh
00401817   rep stos    dword ptr [edi]
00401819   pop         ecx
0040181A   mov         dword ptr [ebp-4],ecx
0040181D   mov         eax,dword ptr [ebp-4]
00401820   mov         ecx,dword ptr [ebp+8]
00401823   mov         dword ptr [eax+4],ecx
00401826   mov         edx,dword ptr [ebp-4]
00401829   mov         dword ptr [edx],offset Base::`vftable' (0046e028)
0040182F   mov         eax,dword ptr [ebp-4]
00401832   pop         edi
00401833   pop         esi
00401834   pop         ebx
00401835   mov         esp,ebp
00401837   pop         ebp
00401838   ret         4
7:        virtual~Base() {}
00401900   push        ebp
00401901   mov         ebp,esp
00401903   sub         esp,44h
00401906   push        ebx
00401907   push        esi
00401908   push        edi
00401909   push        ecx
0040190A   lea         edi,[ebp-44h]
0040190D   mov         ecx,11h
00401912   mov         eax,0CCCCCCCCh
00401917   rep stos    dword ptr [edi]
00401919   pop         ecx
0040191A   mov         dword ptr [ebp-4],ecx
0040191D   mov         eax,dword ptr [ebp-4]
00401920   mov         dword ptr [eax],offset Base::`vftable' (0046e028)
00401926   pop         edi
00401927   pop         esi
00401928   pop         ebx
00401929   mov         esp,ebp
0040192B   pop         ebp
0040192C   ret


8:        void func1() {
004016F0   push        ebp
004016F1   mov         ebp,esp
004016F3   sub         esp,44h
004016F6   push        ebx
004016F7   push        esi
004016F8   push        edi
004016F9   push        ecx
004016FA   lea         edi,[ebp-44h]
004016FD   mov         ecx,11h
00401702   mov         eax,0CCCCCCCCh
00401707   rep stos    dword ptr [edi]
00401709   pop         ecx
0040170A   mov         dword ptr [ebp-4],ecx	//this
9:            i *= 10;
0040170D   mov         eax,dword ptr [ebp-4]
00401710   mov         ecx,dword ptr [eax+4]
00401713   imul        ecx,ecx,0Ah
00401716   mov         edx,dword ptr [ebp-4]
00401719   mov         dword ptr [edx+4],ecx
10:           func2();
0040171C   mov         eax,dword ptr [ebp-4]
0040171F   mov         edx,dword ptr [eax]
00401721   mov         esi,esp
00401723   mov         ecx,dword ptr [ebp-4]	//this
00401726   call        dword ptr [edx+4]
00401729   cmp         esi,esp
0040172B   call        __chkesp (00420e90)
11:       }
00401730   pop         edi
00401731   pop         esi
00401732   pop         ebx
00401733   add         esp,44h
00401736   cmp         ebp,esp
00401738   call        __chkesp (00420e90)
0040173D   mov         esp,ebp
0040173F   pop         ebp
00401740   ret
12:       int getValue() {
00401760   push        ebp
00401761   mov         ebp,esp
00401763   sub         esp,44h
00401766   push        ebx
00401767   push        esi
00401768   push        edi
00401769   push        ecx
0040176A   lea         edi,[ebp-44h]
0040176D   mov         ecx,11h
00401772   mov         eax,0CCCCCCCCh
00401777   rep stos    dword ptr [edi]
00401779   pop         ecx
0040177A   mov         dword ptr [ebp-4],ecx
13:           return  i;
0040177D   mov         eax,dword ptr [ebp-4]
00401780   mov         eax,dword ptr [eax+4]
14:       }
00401783   pop         edi
00401784   pop         esi
00401785   pop         ebx
00401786   mov         esp,ebp
00401788   pop         ebp
00401789   ret
15:       protected:
16:       virtual void func2() {
00401850   push        ebp
00401851   mov         ebp,esp
00401853   sub         esp,44h
00401856   push        ebx
00401857   push        esi
00401858   push        edi
00401859   push        ecx
0040185A   lea         edi,[ebp-44h]
0040185D   mov         ecx,11h
00401862   mov         eax,0CCCCCCCCh
00401867   rep stos    dword ptr [edi]
00401869   pop         ecx
0040186A   mov         dword ptr [ebp-4],ecx
17:           i++;
0040186D   mov         eax,dword ptr [ebp-4]
00401870   mov         ecx,dword ptr [eax+4]
00401873   add         ecx,1
00401876   mov         edx,dword ptr [ebp-4]
00401879   mov         dword ptr [edx+4],ecx
18:       }
0040187C   pop         edi
0040187D   pop         esi
0040187E   pop         ebx
0040187F   mov         esp,ebp
00401881   pop         ebp
00401882   ret

19:       protected:
20:       int i;
21:   };
22:   class Child: public Base {
23:       public:
24:       Child(int j): Base(j) {}
004017A0   push        ebp
004017A1   mov         ebp,esp
004017A3   sub         esp,44h
004017A6   push        ebx
004017A7   push        esi
004017A8   push        edi
004017A9   push        ecx
004017AA   lea         edi,[ebp-44h]
004017AD   mov         ecx,11h
004017B2   mov         eax,0CCCCCCCCh
004017B7   rep stos    dword ptr [edi]
004017B9   pop         ecx
004017BA   mov         dword ptr [ebp-4],ecx
004017BD   mov         eax,dword ptr [ebp+8]
004017C0   push        eax
004017C1   mov         ecx,dword ptr [ebp-4]
004017C4   call        @ILT+35(Base::Base) (00401028)
004017C9   mov         ecx,dword ptr [ebp-4]
004017CC   mov         dword ptr [ecx],offset Child::`vftable' (0046e01c)
004017D2   mov         eax,dword ptr [ebp-4]
004017D5   pop         edi
004017D6   pop         esi
004017D7   pop         ebx
004017D8   add         esp,44h
004017DB   cmp         ebp,esp
004017DD   call        __chkesp (00420e90)
004017E2   mov         esp,ebp
004017E4   pop         ebp
004017E5   ret         4
25:       void func1() {
26:           i *= 100;
27:           func2();
28:       }
29:       protected:
30:       void func2() {
00401940   push        ebp
00401941   mov         ebp,esp
00401943   sub         esp,44h
00401946   push        ebx
00401947   push        esi
00401948   push        edi
00401949   push        ecx
0040194A   lea         edi,[ebp-44h]
0040194D   mov         ecx,11h
00401952   mov         eax,0CCCCCCCCh
00401957   rep stos    dword ptr [edi]
00401959   pop         ecx
0040195A   mov         dword ptr [ebp-4],ecx
31:           i += 2;
0040195D   mov         eax,dword ptr [ebp-4]
00401960   mov         ecx,dword ptr [eax+4]
00401963   add         ecx,2
00401966   mov         edx,dword ptr [ebp-4]
00401969   mov         dword ptr [edx+4],ecx
32:       }
0040196C   pop         edi
0040196D   pop         esi
0040196E   pop         ebx
0040196F   mov         esp,ebp
00401971   pop         ebp
00401972   ret


33:   };
34:   int main() {
004015D0   push        ebp
004015D1   mov         ebp,esp
004015D3   push        0FFh
004015D5   push        offset __ehhandler$_main (00447c4b)
004015DA   mov         eax,fs:[00000000]
004015E0   push        eax
004015E1   mov         dword ptr fs:[0],esp
004015E8   sub         esp,5Ch
004015EB   push        ebx
004015EC   push        esi
004015ED   push        edi
004015EE   lea         edi,[ebp-68h]
004015F1   mov         ecx,17h
004015F6   mov         eax,0CCCCCCCCh
004015FB   rep stos    dword ptr [edi]
35:       Base * pb = new Child(1);
004015FD   push        8
004015FF   call        operator new (004209a0)
00401604   add         esp,4
00401607   mov         dword ptr [ebp-18h],eax
0040160A   mov         dword ptr [ebp-4],0
00401611   cmp         dword ptr [ebp-18h],0
00401615   je          main+56h (00401626)
00401617   push        1
00401619   mov         ecx,dword ptr [ebp-18h]
0040161C   call        @ILT+405(Child::Child) (0040119a)
00401621   mov         dword ptr [ebp-24h],eax			eax == ecx
00401624   jmp         main+5Dh (0040162d)
00401626   mov         dword ptr [ebp-24h],0
0040162D   mov         eax,dword ptr [ebp-24h]
00401630   mov         dword ptr [ebp-14h],eax
00401633   mov         dword ptr [ebp-4],0FFFFFFFFh
0040163A   mov         ecx,dword ptr [ebp-14h]
0040163D   mov         dword ptr [ebp-10h],ecx			this
36:       pb->func1();
00401640   mov         ecx,dword ptr [ebp-10h]
00401643   call        @ILT+160(Base::func1) (004010a5)		this
37:       cout << pb->getValue() << endl;
00401648   push        offset @ILT+220(std::endl) (004010e1)
0040164D   mov         ecx,dword ptr [ebp-10h]
00401650   call        @ILT+575(Base::getValue) (00401244)
00401655   push        eax
00401656   mov         ecx,offset std::cout (0047be90)
0040165B   call        @ILT+280(std::basic_ostream<char,std::char_traits<char> >::operator<<) (0040111d)
00401660   mov         ecx,eax
00401662   call        @ILT+515(std::basic_ostream<char,std::char_traits<char> >::operator<<) (00401208)
38:       delete pb;
00401667   mov         edx,dword ptr [ebp-10h]
0040166A   mov         dword ptr [ebp-20h],edx
0040166D   mov         eax,dword ptr [ebp-20h]
00401670   mov         dword ptr [ebp-1Ch],eax
00401673   cmp         dword ptr [ebp-1Ch],0
00401677   je          main+0C3h (00401693)
00401679   mov         esi,esp
0040167B   push        1
0040167D   mov         ecx,dword ptr [ebp-1Ch]
00401680   mov         edx,dword ptr [ecx]
00401682   mov         ecx,dword ptr [ebp-1Ch]
00401685   call        dword ptr [edx]
00401687   cmp         esi,esp
00401689   call        __chkesp (00420e90)
0040168E   mov         dword ptr [ebp-28h],eax
00401691   jmp         main+0CAh (0040169a)
00401693   mov         dword ptr [ebp-28h],0
39:   }
0040169A   mov         ecx,dword ptr [ebp-0Ch]
0040169D   mov         dword ptr fs:[0],ecx
004016A4   pop         edi
004016A5   pop         esi
004016A6   pop         ebx
004016A7   add         esp,68h
004016AA   cmp         ebp,esp
004016AC   call        __chkesp (00420e90)
004016B1   mov         esp,ebp
004016B3   pop         ebp
004016B4   ret

@ILT+160(?func1@Base@@QAEXXZ):
004010A5   jmp         Base::func1 (004016f0)
@ILT+130(??1Base@@UAE@XZ):
00401087   jmp         Base::~Base (00401900)
@ILT+55(?func2@Child@@MAEXXZ):
0040103C   jmp         Child::func2 (00401940)
@ILT+35(??0Base@@QAE@H@Z):
00401028   jmp         Base::Base (00401800)
@ILT+40(?func2@Base@@MAEXXZ):
0040102D   jmp         Base::func2 (00401850)
@ILT+130(??1Base@@UAE@XZ):
00401087   jmp         Base::~Base (00401900)
@ILT+405(??0Child@@QAE@H@Z):
0040119A   jmp         Child::Child (004017a0)
@ILT+575(?getValue@Base@@QAEHXZ):
00401244   jmp         Base::getValue (00401760)
@ILT+585(_main):
0040124E   jmp         main (004015d0)
@ILT+610(??_EChild@@UAEPAXI@Z):
00401267   jmp         Child::`scalar deleting destructor' (00401980)
@ILT+615(??_EBase@@UAEPAXI@Z):
0040126C   jmp         Base::`scalar deleting destructor' (00401890)
@ILT+660(??1Child@@UAE@XZ):
00401299   jmp         Child::~Child (004019f0)
@ILT+575(?getValue@Base@@QAEHXZ):
00401244   jmp         Base::getValue (00401760)
@ILT+585(_main):
0040124E   jmp         main (004015d0)

@ILT+575(?func1@Child@@UAEXXZ):
00401244   jmp         Child::func1 (00401960)

Child::`scalar deleting destructor':
00401980   push        ebp
00401981   mov         ebp,esp
00401983   sub         esp,44h
00401986   push        ebx
00401987   push        esi
00401988   push        edi
00401989   push        ecx
0040198A   lea         edi,[ebp-44h]
0040198D   mov         ecx,11h
00401992   mov         eax,0CCCCCCCCh
00401997   rep stos    dword ptr [edi]
00401999   pop         ecx
0040199A   mov         dword ptr [ebp-4],ecx
0040199D   mov         ecx,dword ptr [ebp-4]
004019A0   call        @ILT+660(Child::~Child) (00401299)
004019A5   mov         eax,dword ptr [ebp+8]
004019A8   and         eax,1
004019AB   test        eax,eax
004019AD   je          Child::`scalar deleting destructor'+3Bh (004019bb)
004019AF   mov         ecx,dword ptr [ebp-4]
004019B2   push        ecx
004019B3   call        operator delete (00406d20)
004019B8   add         esp,4
004019BB   mov         eax,dword ptr [ebp-4]
004019BE   pop         edi
004019BF   pop         esi
004019C0   pop         ebx
004019C1   add         esp,44h
004019C4   cmp         ebp,esp
004019C6   call        __chkesp (00420e90)
004019CB   mov         esp,ebp
004019CD   pop         ebp
004019CE   ret         4

Base::`scalar deleting destructor':
00401890   push        ebp
00401891   mov         ebp,esp
00401893   sub         esp,44h
00401896   push        ebx
00401897   push        esi
00401898   push        edi
00401899   push        ecx
0040189A   lea         edi,[ebp-44h]
0040189D   mov         ecx,11h
004018A2   mov         eax,0CCCCCCCCh
004018A7   rep stos    dword ptr [edi]
004018A9   pop         ecx
004018AA   mov         dword ptr [ebp-4],ecx
004018AD   mov         ecx,dword ptr [ebp-4]
004018B0   call        @ILT+130(Base::~Base) (00401087)
004018B5   mov         eax,dword ptr [ebp+8]
004018B8   and         eax,1
004018BB   test        eax,eax
004018BD   je          Base::`scalar deleting destructor'+3Bh (004018cb)
004018BF   mov         ecx,dword ptr [ebp-4]
004018C2   push        ecx
004018C3   call        operator delete (00406d20)
004018C8   add         esp,4
004018CB   mov         eax,dword ptr [ebp-4]
004018CE   pop         edi
004018CF   pop         esi
004018D0   pop         ebx
004018D1   add         esp,44h
004018D4   cmp         ebp,esp
004018D6   call        __chkesp (00420e90)
004018DB   mov         esp,ebp
004018DD   pop         ebp
004018DE   ret         4

Child::`scalar deleting destructor':
00401980   push        ebp
00401981   mov         ebp,esp
00401983   sub         esp,44h
00401986   push        ebx
00401987   push        esi
00401988   push        edi
00401989   push        ecx
0040198A   lea         edi,[ebp-44h]
0040198D   mov         ecx,11h
00401992   mov         eax,0CCCCCCCCh
00401997   rep stos    dword ptr [edi]
00401999   pop         ecx
0040199A   mov         dword ptr [ebp-4],ecx
0040199D   mov         ecx,dword ptr [ebp-4]
004019A0   call        @ILT+660(Child::~Child) (00401299)
004019A5   mov         eax,dword ptr [ebp+8]
004019A8   and         eax,1
004019AB   test        eax,eax
004019AD   je          Child::`scalar deleting destructor'+3Bh (004019bb)
004019AF   mov         ecx,dword ptr [ebp-4]
004019B2   push        ecx
004019B3   call        operator delete (00406d20)
004019B8   add         esp,4
004019BB   mov         eax,dword ptr [ebp-4]
004019BE   pop         edi
004019BF   pop         esi
004019C0   pop         ebx
004019C1   add         esp,44h
004019C4   cmp         ebp,esp
004019C6   call        __chkesp (00420e90)
004019CB   mov         esp,ebp
004019CD   pop         ebp
004019CE   ret         4

Child::~Child:
004019F0   push        ebp
004019F1   mov         ebp,esp
004019F3   sub         esp,44h
004019F6   push        ebx
004019F7   push        esi
004019F8   push        edi
004019F9   push        ecx
004019FA   lea         edi,[ebp-44h]
004019FD   mov         ecx,11h
00401A02   mov         eax,0CCCCCCCCh
00401A07   rep stos    dword ptr [edi]
00401A09   pop         ecx
00401A0A   mov         dword ptr [ebp-4],ecx
00401A0D   mov         ecx,dword ptr [ebp-4]
00401A10   call        @ILT+130(Base::~Base) (00401087)
00401A15   pop         edi
00401A16   pop         esi
00401A17   pop         ebx
00401A18   add         esp,44h
00401A1B   cmp         ebp,esp
00401A1D   call        __chkesp (00420e90)
00401A22   mov         esp,ebp
00401A24   pop         ebp
00401A25   ret

若是改成 虚函数func1()
36:       pb->func1();
00401650   mov         edx,dword ptr [ebp-10h]
00401653   mov         eax,dword ptr [edx]
00401655   mov         esi,esp
00401657   mov         ecx,dword ptr [ebp-10h]
0040165A   call        dword ptr [eax+4]


cpp反汇编之protected

标签：反汇编   cpp   

原文地址：http://blog.csdn.net/u011185633/article/details/44779615
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