我有一段特殊的代码片段，我无法理解：

push 0xC           ; arg1 for call
mov ecx,edi        ; set the this pointer for call
call sdk.100039F0  ; make the call (internally calls DeviceIOControl)
push ecx           ; ECX now points to a function within kernelbase.dll
mov ecx,edi        ; set the this pointer for call
call sdk.10003BD0  ; make the call

要在通话DeviceIoControl的第一个函数调用中修改ECX。为什么将其作为参数推送到第二次调用？第二个调用本身不接受参数，它根本不引用[ebp + n]，但它仍然以ret 4.

紧随其后的是第三次调用，它也在内部使用DeviceIOControlthen 函数返回。这第三次调用没有前面的神秘推动。所有这些功能，包括容器，都使用thiscall.

以防万一我错过了什么，这是第二个电话的正文：

push ebp
mov ebp,esp
sub esp,0x30
push ebx
push esi
mov eax,ecx
xor esi,esi
push edi
mov edi,dword ptr ds:[<&DeviceIoControl>]
mov ecx,sdk.10002690
mov dword ptr ss:[ebp-0x8],eax
mov edx,0x8000
test ecx,ecx
je aura_sdk.10003C35
mov ax,word ptr ds:[eax+0x4]
push 0x0
mov word ptr ss:[ebp-0x20],ax
lea eax,dword ptr ss:[ebp-0x14]
push eax
push 0x4
lea eax,dword ptr ss:[ebp-0x4]
mov dword ptr ss:[ebp-0x4],0x0
push eax
push 0x7
lea eax,dword ptr ss:[ebp-0x20]
mov byte ptr ss:[ebp-0x1A],0x1
push eax
push 0x80102050
push dword ptr ds:[0x100375C0]
call edi
mov bl,byte ptr ss:[ebp-0x4]
mov ecx,sdk.10002690
mov edx,0x8000
jmp sdk.10003C37
xor bl,bl
test bl,0x9E
jne sdk.10003C8A
test ecx,ecx
je sdk.10003C7D
push 0x0
mov eax,0xED
mov dword ptr ss:[ebp-0xC],0x0
mov word ptr ss:[ebp-0x28],ax
lea eax,dword ptr ss:[ebp-0x18]
push eax
push 0x4
lea eax,dword ptr ss:[ebp-0xC]
mov byte ptr ss:[ebp-0x22],0x1
push eax
push 0x7
lea eax,dword ptr ss:[ebp-0x28]
push eax
push 0x80102050
push dword ptr ds:[0x100375C0]
call edi
mov ecx,sdk.10002690
mov edx,0x8000
mov eax,dword ptr ss:[ebp-0x8]
inc esi
cmp si,dx
jb sdk.10003BF0
test bl,0x82
je sdk.10003CA3
pop edi
test bl,0x1C
mov eax,0x0
pop esi
sete al
pop ebx
mov esp,ebp
pop ebp
ret 0x4

这是编译器自行纠正的情况还是有目的？