C/C++ 函数调用约定
https://bbs.pediy.com/thread-224583.htm
X86 函数调用约定
X86 有三种常用调用约定，cdecl（C规范）/stdcall（WinAPI 默认）/fastcall 函数调用约定。
cdecl 函数调用约定
参数从右往左依次入栈，调用者实现栈平衡，返回值存放在 EAX 中。
20: int cdecl_sum = cdecl_add(1, 2, 3, 4, 5, 6, 7);
00401138 push 7
0040113A push 6
0040113C push 5
0040113E push 4
00401140 push 3
00401142 push 2
00401144 push 1
00401146 call @ILT+5(_cdecl_add) (0040100a)
0040114B add esp,1Ch # 栈平衡
0040114E mov dword ptr [ebp-4],eax # 返回值
3: int __cdecl cdecl_add(int a, int b, int c, int d, int e, int f, int g)
4: {
00401030 push ebp
00401031 mov ebp,esp
00401033 sub esp,44h
00401036 push ebx
00401037 push esi
00401038 push edi
00401039 lea edi,[ebp-44h]
0040103C mov ecx,11h
00401041 mov eax,0CCCCCCCCh
00401046 rep stos dword ptr [edi]
5: int sum = a+b+c+d+e+f+g;
00401048 mov eax,dword ptr [ebp+8]
0040104B add eax,dword ptr [ebp+0Ch]
0040104E add eax,dword ptr [ebp+10h]
00401051 add eax,dword ptr [ebp+14h]
00401054 add eax,dword ptr [ebp+18h]
00401057 add eax,dword ptr [ebp+1Ch]
0040105A add eax,dword ptr [ebp+20h]
0040105D mov dword ptr [ebp-4],eax
6: return sum;
00401060 mov eax,dword ptr [ebp-4] # 存放返回值
7: }
00401063 pop edi
00401064 pop esi
00401065 pop ebx
00401066 mov esp,ebp
00401068 pop ebp
00401069 ret
stdcall 函数调用约定
参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 EAX 中。
21: int stdcall_sum = stdcall_add(1, 2, 3, 4, 5, 6, 7);
00401151 push 7
00401153 push 6
00401155 push 5
00401157 push 4
00401159 push 3
0040115B push 2
0040115D push 1
0040115F call @ILT+15(_stdcall_add@28) (00401014)
00401164 mov dword ptr [ebp-8],eax # 返回值
9: int __stdcall stdcall_add(int a, int b, int c, int d, int e, int f, int g)
10: {
00401080 push ebp
00401081 mov ebp,esp
00401083 sub esp,44h
00401086 push ebx
00401087 push esi
00401088 push edi
00401089 lea edi,[ebp-44h]
0040108C mov ecx,11h
00401091 mov eax,0CCCCCCCCh
00401096 rep stos dword ptr [edi]
11: int sum = a+b+c+d+e+f+g;
00401098 mov eax,dword ptr [ebp+8]
0040109B add eax,dword ptr [ebp+0Ch]
0040109E add eax,dword ptr [ebp+10h]
004010A1 add eax,dword ptr [ebp+14h]
004010A4 add eax,dword ptr [ebp+18h]
004010A7 add eax,dword ptr [ebp+1Ch]
004010AA add eax,dword ptr [ebp+20h]
004010AD mov dword ptr [ebp-4],eax
12: return sum;
004010B0 mov eax,dword ptr [ebp-4] # 存放返回值
13: }
004010B3 pop edi
004010B4 pop esi
004010B5 pop ebx
004010B6 mov esp,ebp
004010B8 pop ebp
004010B9 ret 1Ch # 栈平衡（等价于先 add esp, 1Ch 再 ret）
fastcall 函数调用约定
参数 1、参数 2 分别保存在 ECX、EDX，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 EAX 中。
25: int fastcall_sum = fastcall_add(1, 2, 3, 4, 5, 6, 7);
00401167 push 7
00401169 push 6
0040116B push 5
0040116D push 4
0040116F push 3
00401171 mov edx,2
00401176 mov ecx,1
0040117B call @ILT+0(@fastcall_add@28) (00401005)
00401180 mov dword ptr [ebp-0Ch],eax # 返回值
15: int __fastcall fastcall_add(int a, int b, int c, int d, int e, int f, int g)
16: {
004010D0 push ebp
004010D1 mov ebp,esp
004010D3 sub esp,4Ch
004010D6 push ebx
004010D7 push esi
004010D8 push edi
004010D9 push ecx
004010DA lea edi,[ebp-4Ch]
004010DD mov ecx,13h
004010E2 mov eax,0CCCCCCCCh
004010E7 rep stos dword ptr [edi]
004010E9 pop ecx
004010EA mov dword ptr [ebp-8],edx
004010ED mov dword ptr [ebp-4],ecx
17: int sum = a+b+c+d+e+f+g;
004010F0 mov eax,dword ptr [ebp-4]
004010F3 add eax,dword ptr [ebp-8]
004010F6 add eax,dword ptr [ebp+8]
004010F9 add eax,dword ptr [ebp+0Ch]
004010FC add eax,dword ptr [ebp+10h]
004010FF add eax,dword ptr [ebp+14h]
00401102 add eax,dword ptr [ebp+18h]
00401105 mov dword ptr [ebp-0Ch],eax
18: return sum;
00401108 mov eax,dword ptr [ebp-0Ch] # 存放返回值
19: }
0040110B pop edi
0040110C pop esi
0040110D pop ebx
0040110E mov esp,ebp
00401110 pop ebp
00401111 ret 14h # 栈平衡（等价于先 add esp, 14h 再 ret）
X64 函数调用约定
X64 只有一种 fastcall 函数调用约定
fastcall 函数调用约定
参数 1、参数 2、参数 3、参数 4 分别保存在 RCX、RDX、R8D、R9D，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 RAX 中。
# 该代码是 msvc 2017 x64 生成的汇编代码
int fastcall_sum = fastcall_add(1, 2, 3, 4, 5, 6, 7);
00007FF6577A366E mov dword ptr [rsp+30h],7
00007FF6577A3676 mov dword ptr [rsp+28h],6
00007FF6577A367E mov dword ptr [rsp+20h],5
00007FF6577A3686 mov r9d,4
00007FF6577A368C mov r8d,3
00007FF6577A3692 mov edx,2
00007FF6577A3697 mov ecx,1
00007FF6577A369C call fastcall_add (07FF6577A11C2h)
00007FF6577A36A1 mov dword ptr [fastcall_sum],eax # 返回值
int __fastcall fastcall_add(int a, int b, int c, int d, int e, int f, int g)
{
00007FF6D22D1790 mov dword ptr [rsp+20h],r9d
00007FF6D22D1795 mov dword ptr [rsp+18h],r8d
00007FF6D22D179A mov dword ptr [rsp+10h],edx
00007FF6D22D179E mov dword ptr [rsp+8],ecx
00007FF6D22D17A2 push rbp
00007FF6D22D17A3 push rdi
00007FF6D22D17A4 sub rsp,0E8h
00007FF6D22D17AB mov rbp,rsp
00007FF6D22D17AE mov rdi,rsp
00007FF6D22D17B1 mov ecx,3Ah
00007FF6D22D17B6 mov eax,0CCCCCCCCh
00007FF6D22D17BB rep stos dword ptr [rdi]
00007FF6D22D17BD mov ecx,dword ptr [rsp+108h]
int sum = a + b + c + d + e + f + g;
00007FF6D22D17C4 mov eax,dword ptr [b]
00007FF6D22D17CA mov ecx,dword ptr [a]
00007FF6D22D17D0 add ecx,eax
00007FF6D22D17D2 mov eax,ecx
00007FF6D22D17D4 add eax,dword ptr [c]
00007FF6D22D17DA add eax,dword ptr [d]
00007FF6D22D17E0 add eax,dword ptr [e]
00007FF6D22D17E6 add eax,dword ptr [f]
00007FF6D22D17EC add eax,dword ptr [g]
00007FF6D22D17F2 mov dword ptr [sum],eax
return sum;
00007FF6D22D17F5 mov eax,dword ptr [sum] # 存放返回值
}
00007FF6D22D17F8 lea rsp,[rbp+0E8h]
00007FF6D22D17FF pop rdi
00007FF6D22D1800 pop rbp
00007FF6D22D1801 ret # 没做栈平衡
ARM/ARM64 函数调用约定
ARM 和 ARM64 使用的是 ATPCS（ARM-Thumb Procedure Call Standard/ARM-Thumb 过程调用标准）的函数调用约定。
ARM
参数 1~参数 4 分别保存到 R0~R3 寄存器中，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 R0 中。
; 该代码是 arm-linux-androideabi-gcc + IDA PRO 生成的反汇编代码
.text:00008438 MOV R3, #5
.text:0000843C STR R3, [SP]
.text:00008440 MOV R3, #6
.text:00008444 STR R3, [SP,#4]
.text:00008448 MOV R3, #7
.text:0000844C STR R3, [SP,#8]
.text:00008450 MOV R3, #8
.text:00008454 STR R3, [SP,#12]
.text:00008458 MOV R3, #9
.text:0000845C STR R3, [SP,#16]
.text:00008460 MOV R3, #10
.text:00008464 STR R3, [SP,#20]
.text:00008468 MOV R0, #1
.text:0000846C MOV R1, #2
.text:00008470 MOV R2, #3
.text:00008474 MOV R3, #4
.text:00008478 BL add
.text:0000847C STR R0, [R11,#-8]
.text:000083C4 EXPORT add
.text:000083C4
.text:000083C4 STR R11, [SP,#-4]!
.text:000083C8 ADD R11, SP, #0
.text:000083CC SUB SP, SP, #0x1C
.text:000083D0 STR R0, [R11,#-16]
.text:000083D4 STR R1, [R11,#-20]
.text:000083D8 STR R2, [R11,#-24]
.text:000083DC STR R3, [R11,#-28]
.text:000083E0 LDR R2, [R11,#-16]
.text:000083E4 LDR R3, [R11,#-20]
.text:000083E8 ADD R2, R2, R3
.text:000083EC LDR R3, [R11,#-24]
.text:000083F0 ADD R2, R2, R3
.text:000083F4 LDR R3, [R11,#-28]
.text:000083F8 ADD R2, R2, R3
.text:000083FC LDR R3, [R11,#4]
.text:00008400 ADD R2, R2, R3
.text:00008404 LDR R3, [R11,#8]
.text:00008408 ADD R2, R2, R3
.text:0000840C LDR R3, [R11,#12]
.text:00008410 ADD R3, R2, R3
.text:00008414 STR R3, [R11,#-8]
.text:00008418 LDR R3, [R11,#-8]
.text:0000841C MOV R0, R3 # 返回值
.text:00008420 SUB SP, R11, #0
.text:00008424 LDR R11, [SP],#4
.text:00008428 BX LR
ARM64
参数 1~参数 8 分别保存到 X0~X7 寄存器中 ，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 X0 中。
; 该代码是 aarch64-linux-android-gcc + IDA PRO 生成的反汇编代码
.text:000000000040065C MOV W0, #9
.text:0000000000400660 STR W0, [SP]
.text:0000000000400664 MOV W0, #10
.text:0000000000400668 STR W0, [SP,#8]
.text:000000000040066C MOV W0, #1
.text:0000000000400670 MOV W1, #2
.text:0000000000400674 MOV W2, #3
.text:0000000000400678 MOV W3, #4
.text:000000000040067C MOV W4, #5
.text:0000000000400680 MOV W5, #6
.text:0000000000400684 MOV W6, #7
.text:0000000000400688 MOV W7, #8
.text:000000000040068C BL add
.text:0000000000400690 STR W0, [X29,#28]
.text:00000000004005E8 EXPORT add
.text:00000000004005E8
.text:00000000004005E8 SUB SP, SP, #0x30
.text:00000000004005EC STR W0, [SP,#28]
.text:00000000004005F0 STR W1, [SP,#24]
.text:00000000004005F4 STR W2, [SP,#20]
.text:00000000004005F8 STR W3, [SP,#16]
.text:00000000004005FC STR W4, [SP,#12]
.text:0000000000400600 STR W5, [SP,#8]
.text:0000000000400604 STR W6, [SP,#4]
.text:0000000000400608 STR W7, [SP]
.text:000000000040060C LDR W1, [SP,#28]
.text:0000000000400610 LDR W0, [SP,#24]
.text:0000000000400614 ADD W1, W1, W0
.text:0000000000400618 LDR W0, [SP,#20]
.text:000000000040061C ADD W1, W1, W0
.text:0000000000400620 LDR W0, [SP,#16]
.text:0000000000400624 ADD W1, W1, W0
.text:0000000000400628 LDR W0, [SP,#12]
.text:000000000040062C ADD W1, W1, W0
.text:0000000000400630 LDR W0, [SP,#8]
.text:0000000000400634 ADD W1, W1, W0
.text:0000000000400638 LDR W0, [SP,#4]
.text:000000000040063C ADD W0, W1, W0
.text:0000000000400640 STR W0, [SP,#44]
.text:0000000000400644 LDR W0, [SP,#44] # 返回值
.text:0000000000400648 ADD SP, SP, #0x30
.text:000000000040064C RET
C++ 函数调用约定
thiscall用于C++中类成员函数（方法）的调用
x86
参数从右往左依次入栈，this 指针存放 ECX 中，被调用者实现栈平衡，返回值存放在 EAX 中。
16: int sum = calc.thiscall_add(1, 2, 3, 4, 5, 6, 7);
00401098 push 7
0040109A push 6
0040109C push 5
0040109E push 4
004010A0 push 3
004010A2 push 2
004010A4 push 1
004010A6 lea ecx,[ebp-4] # this指针
004010A9 call @ILT+0(Calc::thiscall_add) (00401005)
004010AE mov dword ptr [ebp-8],eax # 返回值
7: int Calc::thiscall_add(int a, int b, int c, int d, int e, int f, int g)
8: {
00401020 push ebp
00401021 mov ebp,esp
00401023 sub esp,48h
00401026 push ebx
00401027 push esi
00401028 push edi
00401029 push ecx
0040102A lea edi,[ebp-48h]
0040102D mov ecx,12h
00401032 mov eax,0CCCCCCCCh
00401037 rep stos dword ptr [edi]
00401039 pop ecx
0040103A mov dword ptr [ebp-4],ecx
9: int sum = a + b + c + d + e + f + g;
0040103D mov eax,dword ptr [ebp+8]
00401040 add eax,dword ptr [ebp+0Ch]
00401043 add eax,dword ptr [ebp+10h]
00401046 add eax,dword ptr [ebp+14h]
00401049 add eax,dword ptr [ebp+18h]
0040104C add eax,dword ptr [ebp+1Ch]
0040104F add eax,dword ptr [ebp+20h]
00401052 mov dword ptr [ebp-8],eax
10: return sum;
00401055 mov eax,dword ptr [ebp-8] # 存放返回值
11: }
00401058 pop edi
00401059 pop esi
0040105A pop ebx
0040105B mov esp,ebp
0040105D pop ebp
0040105E ret 1Ch # 栈平衡（等价于先 add esp, 1Ch 再 ret）
X64
参数 1、参数 2、参数 3 分别保存在 RDX、R8D、R9D 中，this 指针存放 RCX 中，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 RAX 中。
# 该代码是 msvc 2017 x64 生成的汇编代码
int sum = calc.thiscall_add(1, 2, 3, 4, 5, 6, 7);
00007FF602E6190F mov dword ptr [rsp+38h],7
00007FF602E61917 mov dword ptr [rsp+30h],6
00007FF602E6191F mov dword ptr [rsp+28h],5
00007FF602E61927 mov dword ptr [rsp+20h],4
00007FF602E6192F mov r9d,3
00007FF602E61935 mov r8d,2
00007FF602E6193B mov edx,1
00007FF602E61940 lea rcx,[calc] # this指针
00007FF602E61944 call Calc::thiscall_add (07FF602E610A0h)
00007FF602E61949 mov dword ptr [sum],eax # 返回值
int Calc::thiscall_add(int a, int b, int c, int d, int e, int f, int g)
{
00007FF602E61770 mov dword ptr [rsp+20h],r9d
00007FF602E61775 mov dword ptr [rsp+18h],r8d
00007FF602E6177A mov dword ptr [rsp+10h],edx
00007FF602E6177E mov qword ptr [rsp+8],rcx
00007FF602E61783 push rbp
00007FF602E61784 push rdi
00007FF602E61785 sub rsp,0E8h
00007FF602E6178C mov rbp,rsp
00007FF602E6178F mov rdi,rsp
00007FF602E61792 mov ecx,3Ah
00007FF602E61797 mov eax,0CCCCCCCCh
00007FF602E6179C rep stos dword ptr [rdi]
00007FF602E6179E mov rcx,qword ptr [rsp+108h]
int sum = a + b + c + d + e + f + g;
00007FF602E617A6 mov eax,dword ptr [b]
00007FF602E617AC mov ecx,dword ptr [a]
00007FF602E617B2 add ecx,eax
00007FF602E617B4 mov eax,ecx
00007FF602E617B6 add eax,dword ptr [c]
00007FF602E617BC add eax,dword ptr [d]
00007FF602E617C2 add eax,dword ptr [e]
00007FF602E617C8 add eax,dword ptr [f]
00007FF602E617CE add eax,dword ptr [g]
00007FF602E617D4 mov dword ptr [sum],eax
return sum;
00007FF602E617D7 mov eax,dword ptr [sum] # 存放返回值
}
00007FF602E617DA lea rsp,[rbp+0E8h]
00007FF602E617E1 pop rdi
00007FF602E617E2 pop rbp
00007FF602E617E3 ret # 没做栈平衡
ARM
参数 1、参数 2、参数 3 分别保存在 R1、R2、R3 中，this 指针存放 R0 中，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 R0 中。
; 该代码是 arm-linux-androideabi-gcc + IDA PRO 生成的反汇编代码
.text:000085BC MOV R3, #4
.text:000085C0 STR R3, [SP] ; int
.text:000085C4 MOV R3, #5
.text:000085C8 STR R3, [SP,#4] ; int
.text:000085CC MOV R3, #6
.text:000085D0 STR R3, [SP,#8] ; int
.text:000085D4 MOV R3, #7
.text:000085D8 STR R3, [SP,#12] ; int
.text:000085DC MOV R3, #8
.text:000085E0 STR R3, [SP,#16] ; int
.text:000085E4 MOV R3, #9
.text:000085E8 STR R3, [SP,#20] ; int
.text:000085EC MOV R3, #10
.text:000085F0 STR R3, [SP,#24] ; int
.text:000085F4 MOV R0, R2 ; this
.text:000085F8 MOV R1, #1 ; int
.text:000085FC MOV R2, #2 ; int
.text:00008600 MOV R3, #3 ; int
.text:00008604 BL _ZN4Calc12thiscall_addEiiiiiiiiii ; Calc::thiscall_add(int,int,int,int,int,int,int,int,int,int)
.text:00008608 MOV R3, R0
.text:00008544 EXPORT _ZN4Calc12thiscall_addEiiiiiiiiii
.text:00008544
.text:00008544 STR R11, [SP,#-4]!
.text:00008548 ADD R11, SP, #0
.text:0000854C SUB SP, SP, #0x1C
.text:00008550 STR R0, [R11,#-16]
.text:00008554 STR R1, [R11,#-20]
.text:00008558 STR R2, [R11,#-24]
.text:0000855C STR R3, [R11,#-28]
.text:00008560 LDR R2, [R11,#-20]
.text:00008564 LDR R3, [R11,#-24]
.text:00008568 ADD R2, R2, R3
.text:0000856C LDR R3, [R11,#-28]
.text:00008570 ADD R2, R2, R3
.text:00008574 LDR R3, [R11,#4]
.text:00008578 ADD R2, R2, R3
.text:0000857C LDR R3, [R11,#8]
.text:00008580 ADD R2, R2, R3
.text:00008584 LDR R3, [R11,#12]
.text:00008588 ADD R2, R2, R3
.text:0000858C LDR R3, [R11,#16]
.text:00008590 ADD R3, R2, R3
.text:00008594 STR R3, [R11,#-8]
.text:00008598 LDR R3, [R11,#-8]
.text:0000859C MOV R0, R3 # 返回值
.text:000085A0 SUB SP, R11, #0
.text:000085A4 LDR R11, [SP],#4
.text:000085A8 BX LR
ARM64
参数 1~参数 7 分别保存到 X1~X7 寄存器中，this 指针存放 X0 中，剩下的参数从右往左依次入栈，被调用者实现栈平衡，返回值存放在 X0 中。
; 该代码是 aarch64-linux-android-gcc + IDA PRO 生成的反汇编代码
.text:00000000004006A0 MOV W0, #8
.text:00000000004006A4 STR W0, [SP] ; int
.text:00000000004006A8 MOV W0, #9
.text:00000000004006AC STR W0, [SP,#8] ; int
.text:00000000004006B0 MOV W0, #10
.text:00000000004006B4 STR W0, [SP,#16] ; int
.text:00000000004006B8 MOV X0, X1 ; this
.text:00000000004006BC MOV W1, #1 ; int
.text:00000000004006C0 MOV W2, #2 ; int
.text:00000000004006C4 MOV W3, #3 ; int
.text:00000000004006C8 MOV W4, #4 ; int
.text:00000000004006CC MOV W5, #5 ; int
.text:00000000004006D0 MOV W6, #6 ; int
.text:00000000004006D4 MOV W7, #7 ; int
.text:00000000004006D8 BL _ZN4Calc12thiscall_addEiiiiiiiiii ; Calc::thiscall_add(int,int,int,int,int,int,int,int,int,int)
.text:00000000004006DC STR W0, [X29,#0x1C]
.text:0000000000400628 EXPORT _ZN4Calc12thiscall_addEiiiiiiiiii
.text:0000000000400628
.text:0000000000400628 SUB SP, SP, #0x40
.text:000000000040062C STR X0, [SP,#40]
.text:0000000000400630 STR W1, [SP,#36]
.text:0000000000400634 STR W2, [SP,#32]
.text:0000000000400638 STR W3, [SP,#28]
.text:000000000040063C STR W4, [SP,#24]
.text:0000000000400640 STR W5, [SP,#20]
.text:0000000000400644 STR W6, [SP,#16]
.text:0000000000400648 STR W7, [SP,#12]
.text:000000000040064C LDR W1, [SP,#36]
.text:0000000000400650 LDR W0, [SP,#32]
.text:0000000000400654 ADD W1, W1, W0
.text:0000000000400658 LDR W0, [SP,#28]
.text:000000000040065C ADD W1, W1, W0
.text:0000000000400660 LDR W0, [SP,#24]
.text:0000000000400664 ADD W1, W1, W0
.text:0000000000400668 LDR W0, [SP,#20]
.text:000000000040066C ADD W1, W1, W0
.text:0000000000400670 LDR W0, [SP,#16]
.text:0000000000400674 ADD W1, W1, W0
.text:0000000000400678 LDR W0, [SP,#12]
.text:000000000040067C ADD W0, W1, W0
.text:0000000000400680 STR W0, [SP,#60]
.text:0000000000400684 LDR W0, [SP,#60] # 返回值
.text:0000000000400688 ADD SP, SP, #0x40
.text:000000000040068C RET