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函数调用方式__stdecl _stdcall _fastcall __thiscall介绍

2011-02-26 23:43 232 查看
__cdecl 是C DECLaration的缩写(declaration,声明),表示C语言默认的函数调用方法:所有参数从右到左依次入栈,这些参数由调用者清除,称为手动清栈。被调用函数不会要求调用者传递多少参数,调用者传递过多或者过少的参数,甚至完全不同的参数都不会产生编译阶段的错误。



_stdcall 是StandardCall的缩写,是C++的标准调用方式:所有参数从右到左依次入栈,如果是调用类成员的话,最后一个入栈的是this指针。这些堆栈中的参数由被调用的函数在返回时清除,使用的指令是 retnX,X表示参数占用的字节数,CPU在ret之后自动弹出X个字节的堆栈空间。称为自动清栈。函数在编译的时候就必须确定参数个数,并且调用者必须严格的控制参数的生成,不能多,不能少,否则返回后会出错。



_fastcall 是编译器指定的快速调用方式。由于大多数的函数参数个数很少,使用堆栈传递比较费时。因此_fastcall通常规定将前两个(或若干个)参数由寄存器传递,其余参数还是通过堆栈传递。不同编译器编译的程序规定的寄存器不同。返回方式和_stdcall相当。





   __thiscall 是为了解决类成员调用中this指针传递而规定的。__thiscall要求把this指针放在特定寄存器中,该寄存器由编译器决定。VC使用ecx,Borland的C++编译器使用eax。返回方式和_stdcall相当。





  _fastcall__thiscall涉及的寄存器由编译器决定,因此不能用作跨编译器的接口。所以Windows上的COM对象接口都定义为_stdcall调用方式。





调用类型
参数入栈顺序
由谁负责清栈
寄存器传递
__stdecl
从右到左依次入栈
调用函数
this
_stdcall
从右到左依次入栈
调用函数
this
_fastcall
从右到左依次入栈
调用函数
this 和参数
__thiscall
从右到左依次入栈
调用函数
this
默认(vs2005)
从右到左依次入栈
调用函数
this
下面来通过代码来查看一下他们到底是如何传递参数和出入栈:





class TestCallType
{
public:
    int default_call(int ,int);
    int __cdecl     __cdecl_call(int a, int b);
    int _stdcall    _stdcall_call(int a, int b);
    int _fastcall   _fastcall_call(int a, int b);
    int __thiscall  _thiscall_call(int,int);
    int x;
};
int TestCallType::default_call(int a, int b)
{
    this->x = a + b;
    return this->x;
}
int TestCallType::__cdecl_call(int a, int b)
{
    this->x = a + b;
    return this->x;
}
int TestCallType::_stdcall_call(int a, int b)
{
    this->x = a + b;
    return this->x;
}
int TestCallType::_fastcall_call(int a, int b)
{
    this->x = a + b;
    return this->x;
}
int TestCallType::_thiscall_call(int a, int b)
{
    this->x = a + b;
    return this->x;
}




调用的地方反汇编出来如下:

int _tmain(int argc, _TCHAR* argv[])
{
004115B0  push        ebp  
004115B1  mov         ebp,esp 
004115B3  sub         esp,0CCh 
004115B9  push        ebx  
004115BA  push        esi  
004115BB  push        edi  
004115BC  lea         edi,[ebp-0CCh] 
004115C2  mov         ecx,33h 
004115C7  mov         eax,0CCCCCCCCh 
004115CC  rep stos    dword ptr es:[edi] 
    TestCallType call_type;
    call_type.default_call(1, 2);
004115CE  push        2                      /* 参数入栈 */
004115D0  push        1    					 /* 参数入栈 */
004115D2  lea         ecx,[call_type]        /* this指针 */
004115D5  call        TestCallType::default_call (411113h) 
    call_type.__cdecl_call(1, 2);
004115DA  push        2    					/* 参数入栈 */
004115DC  push        1    					/* 参数入栈 */
004115DE  lea         eax,[call_type] 		/* this指针 */
004115E1  push        eax  
004115E2  call        TestCallType::__cdecl_call (41112Ch) 
004115E7  add         esp,0Ch               /* 调用者负责清栈 */
    call_type._fastcall_call(1,2);
004115EA  push        2    					/* 参数入栈 */
004115EC  mov         edx,1 				/* 第一个参数通过寄存器传递 */
004115F1  lea         ecx,[call_type] 		/* this指针 */
004115F4  call        TestCallType::_fastcall_call (41100Ah) 
    call_type._stdcall_call(1,2);
004115F9  push        2    
004115FB  push        1    
004115FD  lea         eax,[call_type] 		/* this指针 */
00411600  push        eax  
00411601  call        TestCallType::_stdcall_call (4110EBh) 
    call_type._thiscall_call(1, 2);
00411606  push        2    
00411608  push        1    
0041160A  lea         ecx,[call_type] 		/* this指针 */
0041160D  call        TestCallType::_thiscall_call (41117Ch) 
	return 0;
0041161E  xor         eax,eax 
}




函数定义的地方反汇编:

int TestCallType::default_call(int a, int b)
{
004113D0  push        ebp  
004113D1  mov         ebp,esp 
004113D3  sub         esp,0CCh 
004113D9  push        ebx  
004113DA  push        esi  
004113DB  push        edi  
004113DC  push        ecx  
004113DD  lea         edi,[ebp-0CCh] 
004113E3  mov         ecx,33h 
004113E8  mov         eax,0CCCCCCCCh 
004113ED  rep stos    dword ptr es:[edi] 
004113EF  pop         ecx  
004113F0  mov         dword ptr [ebp-8],ecx 
    this->x = a + b;
004113F3  mov         eax,dword ptr [a] 
004113F6  add         eax,dword ptr [b] 
004113F9  mov         ecx,dword ptr [this] 
004113FC  mov         dword ptr [ecx],eax 
    return this->x;
004113FE  mov         eax,dword ptr [this] 
00411401  mov         eax,dword ptr [eax] 
}
00411403  pop         edi  
00411404  pop         esi  
00411405  pop         ebx  
00411406  mov         esp,ebp 
00411408  pop         ebp                   /* 默认调用是_stdcall 被调用函数负责清栈 */
00411409  ret         8    
--- No source file -------------------------------------------------------------

int TestCallType::__cdecl_call(int a, int b)
{
00411420  push        ebp  
00411421  mov         ebp,esp 
00411423  sub         esp,0C0h 
00411429  push        ebx  
0041142A  push        esi  
0041142B  push        edi  
0041142C  lea         edi,[ebp-0C0h] 
00411432  mov         ecx,30h 
00411437  mov         eax,0CCCCCCCCh 
0041143C  rep stos    dword ptr es:[edi] 
    this->x = a + b;
0041143E  mov         eax,dword ptr [a] 
00411441  add         eax,dword ptr [b] 
00411444  mov         ecx,dword ptr [this] 
00411447  mov         dword ptr [ecx],eax 
    return this->x;
00411449  mov         eax,dword ptr [this] 
0041144C  mov         eax,dword ptr [eax] 
}
0041144E  pop         edi  
0041144F  pop         esi  
00411450  pop         ebx  
00411451  mov         esp,ebp 
00411453  pop         ebp  
00411454  ret                            /* __cdecl 不用负责栈清除 */
--- No source file -------------------------------------------------------------

int TestCallType::_stdcall_call(int a, int b)
{
00411470  push        ebp  
00411471  mov         ebp,esp 
00411473  sub         esp,0C0h 
00411479  push        ebx  
0041147A  push        esi  
0041147B  push        edi  
0041147C  lea         edi,[ebp-0C0h] 
00411482  mov         ecx,30h 
00411487  mov         eax,0CCCCCCCCh 
0041148C  rep stos    dword ptr es:[edi] 
    this->x = a + b;
0041148E  mov         eax,dword ptr [a] 
00411491  add         eax,dword ptr [b] 
00411494  mov         ecx,dword ptr [this] 
00411497  mov         dword ptr [ecx],eax 
    return this->x;
00411499  mov         eax,dword ptr [this] 
0041149C  mov         eax,dword ptr [eax] 
}
0041149E  pop         edi  
0041149F  pop         esi  
004114A0  pop         ebx  
004114A1  mov         esp,ebp 
004114A3  pop         ebp  
004114A4  ret         0Ch                  //清除栈,字节数和参数入栈对应
--- No source file -------------------------------------------------------------

int TestCallType::_fastcall_call(int a, int b)
{
004114C0  push        ebp  
004114C1  mov         ebp,esp 
004114C3  sub         esp,0D8h 
004114C9  push        ebx  
004114CA  push        esi  
004114CB  push        edi  
004114CC  push        ecx  
004114CD  lea         edi,[ebp-0D8h] 
004114D3  mov         ecx,36h 
004114D8  mov         eax,0CCCCCCCCh 
004114DD  rep stos    dword ptr es:[edi] 
004114DF  pop         ecx  
004114E0  mov         dword ptr [ebp-8],edx 
004114E3  mov         dword ptr [ebp-14h],ecx 
    this->x = a + b;
004114E6  mov         eax,dword ptr [a] 
004114E9  add         eax,dword ptr [b] 
004114EC  mov         ecx,dword ptr [this] 
004114EF  mov         dword ptr [ecx],eax 
    return this->x;
004114F1  mov         eax,dword ptr [this] 
004114F4  mov         eax,dword ptr [eax] 
}
004114F6  pop         edi  
004114F7  pop         esi  
004114F8  pop         ebx  
004114F9  mov         esp,ebp 
004114FB  pop         ebp  
004114FC  ret         4                    //清除栈,字节数和参数入栈对应
--- No source file -------------------------------------------------------------

int TestCallType::_thiscall_call(int a, int b)
{
00411510  push        ebp  
00411511  mov         ebp,esp 
00411513  sub         esp,0CCh 
00411519  push        ebx  
0041151A  push        esi  
0041151B  push        edi  
0041151C  push        ecx  
0041151D  lea         edi,[ebp-0CCh] 
00411523  mov         ecx,33h 
00411528  mov         eax,0CCCCCCCCh 
0041152D  rep stos    dword ptr es:[edi] 
0041152F  pop         ecx  
00411530  mov         dword ptr [ebp-8],ecx 
    this->x = a + b;
00411533  mov         eax,dword ptr [a] 
00411536  add         eax,dword ptr [b] 
00411539  mov         ecx,dword ptr [this] 
0041153C  mov         dword ptr [ecx],eax 
    return this->x;
0041153E  mov         eax,dword ptr [this] 
00411541  mov         eax,dword ptr [eax] 
}
00411543  pop         edi  
00411544  pop         esi  
00411545  pop         ebx  
00411546  mov         esp,ebp 
00411548  pop         ebp  
00411549  ret         8                   //清除栈,字节数和参数入栈对应
--- No source file -------------------------------------------------------------
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