cpp反汇编之继承之基类
先分析一个例子。
#include
class CBase
{
public:
CBase()
{
printf("CBase\n");
}
~CBase()
{
printf("~CBase\n");
}
void SetNumber(int nInt)
{
this->m_nNumber = nInt;
}
int GetNumber()
{
return this->m_nNumber;
}
private:
int m_nNumber;
};
class CDerive : public CBase
{
public:
void ShowNumber(int nNumber)
{
SetNumber(nNumber);
m_nDerive = nNumber + 1;
printf("%d\n" , GetNumber());
printf("%d\n" , m_nDerive);
}
public:
int m_nDerive;
};
int main1(int argc , char *argv[])
{
CDerive derive;
derive.ShowNumber(argc);
return 0;
}
int main3()
{
int nTest = 0x87654321;
CBase base;
CDerive *pDerive = (CDerive *)(&base);
printf("%x\n" , pDerive->m_nDerive);
return 0;
} 下面是反汇编分析
此处是函数跳转表
@ILT+0(?SetNumber@CBase@@QAEXH@Z):
00401005 jmp CBase::SetNumber (00401190)
@ILT+5(??1CBase@@QAE@XZ):
0040100A jmp CBase::~CBase (00401300)
@ILT+10(?ShowNumber@CDerive@@QAEXH@Z):
0040100F jmp CDerive::ShowNumber (00401100)
@ILT+15(?GetNumber@CBase@@QAEHXZ):
00401014 jmp CBase::GetNumber (004011d0)
@ILT+20(??0CDerive@@QAE@XZ):
00401019 jmp CDerive::CDerive (00401210)
@ILT+25(??1CDerive@@QAE@XZ):
0040101E jmp CDerive::~CDerive (004012b0)
@ILT+30(_main):
00401023 jmp main (00401060)
@ILT+35(??0CBase@@QAE@XZ):
00401028 jmp CBase::CBase (00401260)
CDerive::CDerive:
00401210 push ebp
00401211 mov ebp,esp
00401213 sub esp,44h
00401216 push ebx
00401217 push esi
00401218 push edi
00401219 push ecx
0040121A lea edi,[ebp-44h]
0040121D mov ecx,11h
00401222 mov eax,0CCCCCCCCh
00401227 rep stos dword ptr [edi]
00401229 pop ecx
0040122A mov dword ptr [ebp-4],ecx ecx即为this指针
0040122D mov ecx,dword ptr [ebp-4]
00401230 call @ILT+35(CBase::CBase) (00401028)
00401235 mov eax,dword ptr [ebp-4]
00401238 pop edi
00401239 pop esi
0040123A pop ebx
0040123B add esp,44h
0040123E cmp ebp,esp
00401240 call __chkesp (00401730)
00401245 mov esp,ebp
00401247 pop ebp
00401248 ret
CDerive::~CDerive:
004012B0 push ebp
004012B1 mov ebp,esp
004012B3 sub esp,44h
004012B6 push ebx
004012B7 push esi
004012B8 push edi
004012B9 push ecx
004012BA lea edi,[ebp-44h]
004012BD mov ecx,11h
004012C2 mov eax,0CCCCCCCCh
004012C7 rep stos dword ptr [edi]
004012C9 pop ecx
004012CA mov dword ptr [ebp-4],ecx
004012CD mov ecx,dword ptr [ebp-4]
004012D0 call @ILT+5(CBase::~CBase) (0040100a)
004012D5 pop edi
004012D6 pop esi
004012D7 pop ebx
004012D8 add esp,44h
004012DB cmp ebp,esp
004012DD call __chkesp (00401730)
004012E2 mov esp,ebp
004012E4 pop ebp
004012E5 ret
1: #include
2:
3: class CBase
4: {
5: public:
6: CBase()
00401260 push ebp
00401261 mov ebp,esp
00401263 sub esp,44h
00401266 push ebx
00401267 push esi
00401268 push edi
00401269 push ecx
0040126A lea edi,[ebp-44h]
0040126D mov ecx,11h
00401272 mov eax,0CCCCCCCCh
00401277 rep stos dword ptr [edi]
00401279 pop ecx
0040127A mov dword ptr [ebp-4],ecx
7: {
8: printf("CBase\n");
0040127D push offset string "CBase\n" (00425020)
00401282 call printf (00401860)
00401287 add esp,4
9: }
0040128A mov eax,dword ptr [ebp-4]
0040128D pop edi
0040128E pop esi
0040128F pop ebx
00401290 add esp,44h
00401293 cmp ebp,esp
00401295 call __chkesp (00401730)
0040129A mov esp,ebp
0040129C pop ebp
0040129D ret
10: ~CBase()
11: {
00401300 push ebp
00401301 mov ebp,esp
00401303 sub esp,44h
00401306 push ebx
00401307 push esi
00401308 push edi
00401309 push ecx
0040130A lea edi,[ebp-44h]
0040130D mov ecx,11h
00401312 mov eax,0CCCCCCCCh
00401317 rep stos dword ptr [edi]
00401319 pop ecx 还原ecx指针
0040131A mov dword ptr [ebp-4],ecx
12: printf("~CBase\n");
0040131D push offset string "~CBase\n" (00425028)
00401322 call printf (00401860)
00401327 add esp,4
13: }
0040132A pop edi
0040132B pop esi
0040132C pop ebx
0040132D add esp,44h
00401330 cmp ebp,esp
00401332 call __chkesp (00401730)
00401337 mov esp,ebp
00401339 pop ebp
0040133A ret
14: void SetNumber(int nInt)
15: {
00401190 push ebp
00401191 mov ebp,esp
00401193 sub esp,44h
00401196 push ebx
00401197 push esi
00401198 push edi
00401199 push ecx
0040119A lea edi,[ebp-44h]
0040119D mov ecx,11h
004011A2 mov eax,0CCCCCCCCh
004011A7 rep stos dword ptr [edi]
004011A9 pop ecx
004011AA mov dword ptr [ebp-4],ecx
16: this->m_nNumber = nInt;
004011AD mov eax,dword ptr [ebp-4]
004011B0 mov ecx,dword ptr [ebp+8]
004011B3 mov dword ptr [eax],ecx
17: }
004011B5 pop edi
004011B6 pop esi
004011B7 pop ebx
004011B8 mov esp,ebp
004011BA pop ebp
004011BB ret 4
18: int GetNumber()
19: {
004011D0 push ebp
004011D1 mov ebp,esp
004011D3 sub esp,44h
004011D6 push ebx
004011D7 push esi
004011D8 push edi
004011D9 push ecx
004011DA lea edi,[ebp-44h]
004011DD mov ecx,11h
004011E2 mov eax,0CCCCCCCCh
004011E7 rep stos dword ptr [edi]
004011E9 pop ecx
004011EA mov dword ptr [ebp-4],ecx
20: return this->m_nNumber;
004011ED mov eax,dword ptr [ebp-4]
004011F0 mov eax,dword ptr [eax]
21: }
004011F2 pop edi
004011F3 pop esi
004011F4 pop ebx
004011F5 mov esp,ebp
004011F7 pop ebp
004011F8 ret
22: private:
23: int m_nNumber;
24: };
25:
26: class CDerive : public CBase
27: {
28: public:
29: void ShowNumber(int nNumber)
30: {
00401100 push ebp
00401101 mov ebp,esp
00401103 sub esp,44h
00401106 push ebx
00401107 push esi
00401108 push edi
00401109 push ecx
0040110A lea edi,[ebp-44h]
0040110D mov ecx,11h
00401112 mov eax,0CCCCCCCCh
00401117 rep stos dword ptr [edi]
00401119 pop ecx
0040111A mov dword ptr [ebp-4],ecx
31: SetNumber(nNumber);
0040111D mov eax,dword ptr [ebp+8]
00401120 push eax
00401121 mov ecx,dword ptr [ebp-4]
00401124 call @ILT+0(CBase::SetNumber) (00401005)
32: m_nDerive = nNumber + 1;
00401129 mov ecx,dword ptr [ebp+8]
0040112C add ecx,1
0040112F mov edx,dword ptr [ebp-4]
00401132 mov dword ptr [edx+4],ecx
33: printf("%d\n" , GetNumber());
00401135 mov ecx,dword ptr [ebp-4]
00401138 call @ILT+15(CBase::GetNumber) (00401014)
0040113D push eax
0040113E push offset string "%d\n" (0042501c)
00401143 call printf (00401860)
00401148 add esp,8
34: printf("%d\n" , m_nDerive);
0040114B mov eax,dword ptr [ebp-4]
0040114E mov ecx,dword ptr [eax+4]
00401151 push ecx
00401152 push offset string "%d\n" (0042501c)
00401157 call printf (00401860)
0040115C add esp,8
35: }
0040115F pop edi
00401160 pop esi
00401161 pop ebx
00401162 add esp,44h
00401165 cmp ebp,esp
00401167 call __chkesp (00401730)
0040116C mov esp,ebp
0040116E pop ebp
0040116F ret 4
36: private:
37: int m_nDerive;
38: };
39:
40: int main(int argc , char *argv[])
41: {
00401060 push ebp
00401061 mov ebp,esp
00401063 push 0FFh
00401065 push offset __ehhandler$_main (00413429)
0040106A mov eax,fs:[00000000]
00401070 push eax
00401071 mov dword ptr fs:[0],esp
00401078 sub esp,4Ch
0040107B push ebx
0040107C push esi
0040107D push edi
0040107E lea edi,[ebp-58h]
00401081 mov ecx,13h
00401086 mov eax,0CCCCCCCCh
0040108B rep stos dword ptr [edi]
42: CDerive derive;
0040108D lea ecx,[ebp-14h]
00401090 call @ILT+20(CDerive::CDerive) (00401019)
00401095 mov dword ptr [ebp-4],0
43: derive.ShowNumber(argc);
0040109C mov eax,dword ptr [ebp+8]
0040109F push eax
004010A0 lea ecx,[ebp-14h]
004010A3 call @ILT+10(CDerive::ShowNumber) (0040100f)
44: return 0;
004010A8 mov dword ptr [ebp-18h],0
004010AF mov dword ptr [ebp-4],0FFFFFFFFh
004010B6 lea ecx,[ebp-14h]
004010B9 call @ILT+25(CDerive::~CDerive) (0040101e)
004010BE mov eax,dword ptr [ebp-18h]
45: }
004010C1 mov ecx,dword ptr [ebp-0Ch]
004010C4 mov dword ptr fs:[0],ecx
004010CB pop edi
004010CC pop esi
004010CD pop ebx
004010CE add esp,58h
004010D1 cmp ebp,esp
004010D3 call __chkesp (00401730)
004010D8 mov esp,ebp
004010DA pop ebp
004010DB ret
父类有构造函数子类没有则编译器提供一个默认的。子类有父类没有则不一定提供。除非有虚函数等。
46: int main()
47: {
00401360 push ebp
00401361 mov ebp,esp
00401363 sub esp,50h
00401366 push ebx
00401367 push esi
00401368 push edi
00401369 lea edi,[ebp-50h]
0040136C mov ecx,14h
00401371 mov eax,0CCCCCCCCh
00401376 rep stos dword ptr [edi]
48: int nTest = 0x87654321;
00401378 mov dword ptr [ebp-4],87654321h
49: CBase base;
0040137F lea ecx,[ebp-8]
00401382 call @ILT+40(CBase::CBase) (0040102d)
50: CDerive *pDerive = (CDerive *)(&base);
00401387 lea eax,[ebp-8]
0040138A mov dword ptr [ebp-0Ch],eax
51: printf("%x\n" , pDerive->m_nDerive);
0040138D mov ecx,dword ptr [ebp-0Ch]
00401390 mov edx,dword ptr [ecx+4] //指针偏移,注意此处是指针偏移,指针可以为NULL NULL + 4不是NULL,不会出现空指针异常
00401393 push edx
00401394 push offset string "%x\n" (00425034)
00401399 call printf (00401930)
0040139E add esp,8
52: return 0;
004013A1 mov dword ptr [ebp-10h],0
004013A8 lea ecx,[ebp-8]
004013AB call @ILT+5(CBase::~CBase) (0040100a)
004013B0 mov eax,dword ptr [ebp-10h]
53: }
004013B3 pop edi
004013B4 pop esi
004013B5 pop ebx
004013B6 add esp,50h
004013B9 cmp ebp,esp
004013BB call __chkesp (00401800)
004013C0 mov esp,ebp
004013C2 pop ebp
004013C3 ret