ARM汇编

作者: 7b33a23272c4 | 来源:发表于2017-08-07 11:08 被阅读666次

一. ARM 寄存器

ARM共有37个32位寄存器,其中31个为通用寄存器,6个为状态寄存器.这些寄存器不能被同时访问,但在任何时候,通用寄存器R0~R14,程序计数器PC,一个或两个状态寄存器都是可访问的.

ARM寄存器

arm64有32个64bit长度的通用寄存器x0～x30，sp，可以只使用其中的32bit w0～w30。 arm32只有16个32bit的通用寄存器r0~r12, lr, pc, sp. arm64有32个128bit SIMD寄存器v0～v31，arm32有16个128bit SIMD寄存器Q0～Q15，又可细分为32个64bit SIMD寄存器D0～D31
函数调用：arm64前面8个参数都是通过寄存器来传递x0～x7， arm32前面4个参数通过寄存器来传递r0～r3，其他通过栈传递
iOS中ARMv7以及ARM64下的ABI：
- ARMv7中，对于通用寄存器，自己写的过程中需要保护R4、R5、R6、R7、R8、R9、R10、R11以及R14寄存器；NEON寄存器需要保存Q4、Q5、Q6、Q7寄存器。
- ARM64模式下，通用寄存器X18、X30不能被使用。而需要被自己写的过程所保护的是：X19、X20、X21、X22、X23、X24、X25、X26、X27、X28、X29寄存器；而SIMD寄存器需要保护的是V8、V9、V10、V11、V12、V13、V14、V15。

二. ARM汇编指令简介

常用寄存器

寄存器	位数	描述
X0-X30	64bit	64位通用寄存器
WO-W30	32bit	32位通用寄存器
FP(x29)	64bit	栈底指针
LR (X30)	64bit	程序链接寄存器，保存跳转返回信息地址
SP	64bit	保存栈指针
PC	64bit	程序计数器，又称PC指针，指向下一条指令

通用寄存器名称

位数通用 0寄存器栈指针

32bit Wn WZR WSP

64bit Xn XZR SP

位数	通用	0寄存器	栈指针
32bit	Wn	WZR	WSP
64bit	Xn	XZR	SP

通用寄存器用法

X0-X7   用于函数调用时参数传递，X0一般用作返回值
X8      间接寻址结果
X29     通常用作FP
X30     通常用作LR

常用的汇编指令

MOV X1, X0  ;寄存器X0的值传给X1
ADD X0, X1, X2  ;寄存器X1和X2的值相加后给X0
SUB X0, X1, X2  ;寄存器X1和X2的值相减后给X0

AND X0, X0, #0xF    ;X0和0xF相与后的值给X0
ORR X0, X0, #0x10   ;X0和0x10相或后的值给X0
EOR X0, X0, #0x11   ;X0和0x11相异或后的值给X0

LDR(LDUR) X5, [X6, #0x8]  ;X6寄存器的值(地址)加0x8的地址内的值给X5
STR(STUR) X0, [SP, #0x8]  ;X0的值给(SP+0x8)地址指向的空间

STP X29, X30, [SP, #0x1]    ;入栈操作
LDP X29, X30, [SP, #0x1]    ;出栈操作

CBZ     比较，如果结果为0，就跳转到后面的指令
CBNZ    比较，如果结果非0，就跳转到后面的指令

CMP     比较指令，结果影响CSPR状态

B/BL    绝对跳转,无返回值/绝对跳转,返回值地址保存到LR(X30)
RET     子程序返回，返回地址保存到LR(X30)

ADRP    用来定位数据段中的数据, 因为ASLR会导致代码及数据的地址随机化, 用ADRP来根据PC做辅助定位

三. 反汇编

MacOS终端编译文件命令：将1.m 编译成 arm1

clang -O0 -arch arm64 -isysroot `xcrun --sdk iphoneos --show-sdk-path` -o arm1 1.m

赋值、加法和减法运算

C语言：

#include <stdio.h>
int main(int argc, char* argv[])
{
    int a = 0x1234;
    int b = a + 0x1122;
    int c = a + 0x2233;
    return 0;
}

Hopper查看反汇编代码：

                    _main:
0000000100007f70    sub     sp, sp, #0x20 ;分配0x20个的内存空间
0000000100007f74    movz    w8, #0x0      ;w8=0x0
0000000100007f78    movz    w9, #0x2233   ;w9=0x2233
0000000100007f7c    movz    w10, #0x1122  ;w10=0x1122
0000000100007f80    movz    w11, #0x1234  ;w11=0x1234
0000000100007f84    str     wzr, [sp, #0x1c]  ;(sp+0x1c)=wzr
0000000100007f88    str     w0, [sp, #0x18]  ;(sp+0x18)=w0
0000000100007f8c    str     x1, [sp, #0x10]  ;(sp+0x10)=x1
0000000100007f90    str     w11, [sp, #0xc]  ;(sp+0xc)=w11
0000000100007f94    ldr     w11, [sp, #0xc]  ;w11 = (sp+oxc)
0000000100007f98    add     w10, w11, w10    ;w10 = w11+w10
0000000100007f9c    str     w10, [sp, #0x8]  ;(sp+0x8)=w10
0000000100007fa0    ldr     w10, [sp, #0xc]  ;w10=(sp+0xc)
0000000100007fa4    add     w9, w10, w9      ;w9 = w10+w9
0000000100007fa8    str     w9, [sp, #0x4]   ;(sp+0x4) = w9
0000000100007fac    mov     x0, x8           ;x0 = x8
0000000100007fb0    add     sp, sp, #0x20  ;释放分配0x20个空间
0000000100007fb4    ret        
                    ; endp

与、或和异或运算

C语言：

#include <stdio.h>
int main(int argc, char* argv[])
{
    int a = 0x3;
    int b = a & 0xf;
    int c = a | 0xe;
    int d = a ^ 0xd;
    int e = ~a;
    return 0;
}

反汇编代码：

                    _main:
0000000100007f58    sub   sp, sp, #0x30 
0000000100007f5c    movz  w8, #0x0      ;w8=0
0000000100007f60    movn  w9, #0x0      ;w9=0;
0000000100007f64    movz  w10, #0xd     ;w10=0xd;
0000000100007f68    orr   w11, wzr, #0x3    ;w11 = wzr | 0x3 = 0x3;
0000000100007f6c    str   wzr, [sp, #0x2c]  ;(sp+0x2c) = wzr
0000000100007f70    str   w0, [sp, #0x28]   ;(sp+0x28) = w0
0000000100007f74    str   x1, [sp, #0x20]   ;(sp+0x20) = x1
0000000100007f78    str   w11, [sp, #0x1c]  ;(sp+0x1c) = w11
0000000100007f7c    ldr   w11, [sp, #0x1c]  ;w11 = (sp+0x1c)
0000000100007f80    and   w11, w11, #0xf    ;w11 = w11 & 0xf
0000000100007f84    str   w11, [sp, #0x18]  ;(sp+0x18) = w11
0000000100007f88    ldr   w11, [sp, #0x1c]  ;w11 = (sp+0x1c) = 0x3
0000000100007f8c    orr   w11, w11, #0xe    ;w11 = w11 | 0x3 = 0x3 | 0xe
0000000100007f90    str   w11, [sp, #0x14]  ;(sp+0x14) = w11
0000000100007f94    ldr   w11, [sp, #0x1c]  ;w11 = (sp+0x1c) = 0x3
0000000100007f98    eor   w10, w11, w10     ;w10 = w11 ^ w10 = 0xd ^ 0x3
0000000100007f9c    str   w10, [sp, #0x10]  ;(sp+0x10) = w10
0000000100007fa0    ldr   w10, [sp, #0x1c]  ;w10 = (sp+0x1c) = 0x3
0000000100007fa4    eor   w9, w10, w9       ;w9 = w10 ^ w9 = 0x3 ^ 0 = ~a
0000000100007fa8    str   w9, [sp, #0xc]    ;(sp+0xc) = w9
0000000100007fac    mov   x0, x8            ;x0 = x8 = 0
0000000100007fb0    add   sp, sp, #0x30
0000000100007fb4    ret 
                    ; endp

比较

CSPR条件码标记：
N、Z、C、V均为条件码标志位。它们的内容可被算术或逻辑运算的结果所改变，并且可以决定某条指令是否被执行。

标志位	描述
N	当两个有符号整数运算时： N=1表示运算的结果为负数； N=0表示运算的结果为正数或零
Z	Z=1表示运算的结果为零 Z=0表示运算的结果非零对于CMP指令，Z=1表示进行比较的两个数相等
C	可以有4种方法设置C的值： 1. 在加法指令中(包括CMP指令)，当结果产生了进位,则C=1,表示无符号运算发生上溢出；其他情况C=0 2. 在减法指令中(包括CMP指令)，当运算中发生借位，则C=0，表示无符号运算数发生下溢出；其他情况下C=1 3. 对于包含移位操作的非加减运算指令，C中包含最后一次溢出的位的数值 4.对于其他非加减运算指令，C位的值通常不受影响
V	对于加减运算指令，当操作数和运算结果为二进制的补码表示的带符号数时，V=1表示符号位溢出；通常其他指令不影响V位

常见的指令的条件码

条件码助记符	标志	描述
NE	Z清零	不相等
EQ	Z置位	相等
LE	Z清零或（N不等于V）	带符号数小于或等于
GE	N等于V	带符号数大于或等于
LT	N不等于V	带符号数小于
GT	Z清零且（N等于V）	带符号数大于
HI	C置位Z清零	无符号数大于
LS	Z置位C清零	无符号数小于或等于
CC(LO)	C清零	无符号数小于
CS(HS)	C置位	无符号数大于或等于

C语言：

#include <stdio.h>

int main(int argc, char* argv[])
{
   int a = 3;
   unsigned int b;
   if(a>3) b = 1;
   if(a<3) b = 2;
   if(a==3) b = 0;
   unsigned int c = 4;
   if(b>c) a  = 1;
   else a = 2;
   return 0;
}

反汇编代码：

                    _main:
0000000100007f2c    sub     sp, sp, #0x20 
0000000100007f30    orr     w8, wzr, #0x3
0000000100007f34    str     wzr, [sp, #0x1c]    ;(sp + 0x1c) = wzr = 0
0000000100007f38    str     w0, [sp, #0x18]     ;(sp + 0x18) = wo 
0000000100007f3c    str     x1, [sp, #0x10]     ;(sp + 0x10) = x1
0000000100007f40    str     w8, [sp, #0xc]      ;(sp + 0xc) = w8 = 0x3
0000000100007f44    ldr     w8, [sp, #0xc]      ;w8 = (sp + 0xc) = 0x3
0000000100007f48    cmp     w8, #0x3            ;w8和3比较
0000000100007f4c    b.le    0x100007f58 ;如果有符号数w8小于等于3则跳转执行 0x100007f58指令

;如果w8>3则执行这里(按顺序执行)
0000000100007f50    orr     w8, wzr, #0x1 ;w8 = wzr | 0x1 = 1
0000000100007f54    str     w8, [sp, #0x8] ;(sp+0x8) = w8 = 1

0000000100007f58    ldr     w8, [sp, #0xc]  ;w8 = (sp+0xc) = 3
0000000100007f5c    cmp     w8, #0x3        ;w8和3进行比较
0000000100007f60    b.ge    0x100007f6c ;如果有符号数w8大于等于3则跳转执行 0x100007f6c

;如果w8<3则执行这里
0000000100007f64    orr     w8, wzr, #0x2  ;w8 = wzr | 0x2 = 2
0000000100007f68    str     w8, [sp, #0x8] ;(sp+0x8) = w8 = 2

0000000100007f6c    ldr     w8, [sp, #0xc]  ;w8 = (sp+0xc) = 3
0000000100007f70    cmp     w8, #0x3        ;w8和3比较
0000000100007f74    b.ne    0x100007f7c ;如果有符号数w8不等于3则跳转执行 0x100007f7c

;如果w8==3则执行这里
0000000100007f78    str     wzr, [sp, #0x8] ; (sp+0x8) = wzr = 0 即： b=0

0000000100007f7c    orr     w8, wzr, #0x4  ; w8 = wzr | 0x4 = 0x4
0000000100007f80    str     w8, [sp, #0x4] ;（sp+0x4) = w8 = 0x4
0000000100007f84    ldr     w8, [sp, #0x8] ; w8 = (sp+0x8) = 0
0000000100007f88    ldr     w9, [sp, #0x4] ; w9 = (sp+0x4) = 0x4
0000000100007f8c    cmp     w8, w9 ;w8和w9进行比较
0000000100007f90    b.ls    0x100007fa0 ;如果无符号数w8小于等于w9，则跳转执行0x100007fa0

0000000100007f94    orr     w8, wzr, #0x1  ;w8 = wzr | 0x1 = 1
0000000100007f98    str     w8, [sp, #0xc] ;(sp+oxc) = w8
0000000100007f9c    b       0x100007fa8    ;跳转执行 0x100007fa8

0000000100007fa0    orr     w8, wzr, #0x2 ; w8 = wzr | 0x2 = 2
0000000100007fa4    str     w8, [sp, #0xc]; (sp+0xc) = w8 = 2 即：a=2

0000000100007fa8    movz    w8, #0x0  
0000000100007fac    mov     x0, x8
0000000100007fb0    add     sp, sp, #0x20
0000000100007fb4    ret     
                    ; endp

for循环

C语言：

#include <stdio.h>

int main(int argc, char* argv[])
{
    for(int a=0; a<10; a++){
    printf("a = %d\n",a);
    }
    return 0;
}

反汇编代码：

                     _main:
0000000100007f14   sub    sp, sp, #0x30 
0000000100007f18   stp    x29, x30, [sp, #0x20]
0000000100007f1c   add    x29, sp, #0x20
0000000100007f20   stur   wzr, [x29, #0xfffffffc]
0000000100007f24   stur   w0, [x29, #0xfffffff8]
0000000100007f28   str    x1, [sp, #0x10]
0000000100007f2c   str    wzr, [sp, #0xc] ;(sp+0xc) = wzr = 0

0000000100007f30   ldr    w8, [sp, #0xc] ;w8 = (sp+0xc) = 0
0000000100007f34   cmp    w8, #0xa    ;w8和0xa进行比较
0000000100007f38   b.ge   0x100007f6c ;w8>=10 则跳转执行0x100007f6c

0000000100007f3c   ldr    w8, [sp, #0xc] ;w8= (sp+0xc) = 0
0000000100007f40   mov    x0, x8         ;x0 = x8
0000000100007f44   mov    x9, sp         ;x9 = sp
0000000100007f48   str    x0, [x9]       ;(x9) = x0 
0000000100007f4c   adrp   x0, #0x100007000 
0000000100007f50   add    x0, x0, #0xfb0 ;x0 = x0+0xfb0
0000000100007f54   bl     imp___stubs__printf ;调用打印
0000000100007f58   str    w0, [sp, #0x8]    ;(sp+0x8) = w0 
0000000100007f5c   ldr    w8, [sp, #0xc]    ;w8 = (sp+0xc) = 0
0000000100007f60   add    w8, w8, #0x1      ;w8 = w8+0x1
0000000100007f64   str    w8, [sp, #0xc]    ;(sp+0xc) = w8
0000000100007f68   b      0x100007f30       ;无条件跳转 0x100007f30

0000000100007f6c   movz   w8, #0x0 
0000000100007f70   mov    x0, x8
0000000100007f74   ldp    x29, x30, [sp, #0x20]
0000000100007f78   add    sp, sp, #0x30
0000000100007f7c   ret        
                  ; endp

while

C语言：

#include <stdio.h>
int main(int argc, char* argv[])
{
    int a = 0;
    while(a<10){
    printf("a = %d\n",a);
    a++;
    }
    return 0;
}

反汇编代码：

                     _main:
0000000100007f14   sub    sp, sp, #0x30   
0000000100007f18   stp    x29, x30, [sp, #0x20]
0000000100007f1c   add    x29, sp, #0x20
0000000100007f20   stur   wzr, [x29, #0xfffffffc]
0000000100007f24   stur   w0, [x29, #0xfffffff8]
0000000100007f28   str    x1, [sp, #0x10]
0000000100007f2c   str    wzr, [sp, #0xc]  ; (sp+0xc) = wzr = 0

0000000100007f30   ldr    w8, [sp, #0xc]    ;w8 = (sp+0xc) 
0000000100007f34   cmp    w8, #0xa          ;w8和10进行比较
0000000100007f38   b.ge   0x100007f6c       ;如果大于等于10则跳转到0x100007f6c

0000000100007f3c   ldr    w8, [sp, #0xc]    ;w8 = (sp+0xc)
0000000100007f40   mov    x0, x8    ;输出相关逻辑
0000000100007f44   mov    x9, sp
0000000100007f48   str    x0, [x9]
0000000100007f4c   adrp   x0, #0x100007000 imp___stubs__printf
0000000100007f50   add    x0, x0, #0xfb0  
0000000100007f54   bl     imp___stubs__printf ;输出逻辑结束
0000000100007f58   ldr    w8, [sp, #0xc]    ;w8 = (sp+0xc) 
0000000100007f5c   add    w8, w8, #0x1      ;w8 = w8+1
0000000100007f60   str    w8, [sp, #0xc]    ;(sp+0xc) = w8
0000000100007f64   str    w0, [sp, #0x8]    ;(sp+0x8) = w0
0000000100007f68   b      0x100007f30       ;跳转 -> 0x100007f30

0000000100007f6c   movz   w8, #0x0   
0000000100007f70   mov    x0, x8
0000000100007f74   ldp    x29, x30, [sp, #0x20]
0000000100007f78   add    sp, sp, #0x30
0000000100007f7c   ret    
                    ; endp

switch语句

C语言：

#include <stdio.h>

int main(int argc, char* argv[])
{
    int a = 3;
    int b = 5;
    switch(a){
        case 0:  b=6; break;
        case 1:  b=7; break;
        case 2:  b=8; break;
        case 3:  b=9; break;
        default:  b=0; break;
    }
    printf("b = %d\n", b);
    return 0;
}

反汇编代码：

                   _main:
0000000100007ea8   sub    sp, sp, #0x40  
0000000100007eac   stp    x29, x30, [sp, #0x30] ;分配0x30个内存空间
0000000100007eb0   add    x29, sp, #0x30 ;栈底指针
0000000100007eb4   movz   w8, #0x0               ; w8 = 0
0000000100007eb8   stur   w8, [x29, #0xfffffffc] ;(x29+0xfffffffc) = w8 = 0
0000000100007ebc   stur   w0, [x29, #0xfffffff8] ;(x29+0xfffffff8) = w0
0000000100007ec0   stur   x1, [x29, #0xfffffff0] ;(x29+0xfffffff0) = x1
0000000100007ec4   orr    w8, wzr, #0x3          ;w8 = wzr | 0x3 = 0x3
0000000100007ec8   stur   w8, [x29, #0xffffffec] ;(x29+0xffffffec) = w8 = 0x3
0000000100007ecc   movz   w8, #0x5      ;w8 = 0x5
0000000100007ed0   str    w8, [sp, #0x18]   ;(sp+0x18) = w8 = 0x5
0000000100007ed4   ldur   w8, [x29, #0xffffffec]    ;w8=(x29+0xffffffec)=0x3
0000000100007ed8   mov    x1, x8
0000000100007edc   mov    x8, x1
0000000100007ee0   subs   w8, w8, #0x3  ;w8 = w8-0x3 = 0   #0x3 为switch语句中条件的个数-1
0000000100007ee4   str    x1, [sp, #0x10]   ;(sp+0x10) = x1
0000000100007ee8   str    w8, [sp, #0xc]    ;(sp+0xc) = w8 = 0
0000000100007eec   b.hi   0x100007f38   ;无符号数大于则跳转0x100007f38,即跳default

0000000100007ef0   adrp   x8, #0x100007000
0000000100007ef4   add    x8, x8, #0xf70     ; 0x100007f70
0000000100007ef8   ldr    x9, [sp, #0x10]   ;x9 = (sp+0x10)
0000000100007efc   ldrsw  x10, [x8, x9, lsl #2] 
0000000100007f00   add    x8, x10, x8   ;x8 = x10 + x8
0000000100007f04   br     x8    ;跳转x8
0000000100007f08   orr    w8, wzr, #0x6     ; w8 = 0x6
0000000100007f0c   str    w8, [sp, #0x18]   ;(sp + 0x18) = w8
0000000100007f10   b      0x100007f3c       ;跳转

0000000100007f14   orr    w8, wzr, #0x7     ;w8 = 0x7
0000000100007f18   str    w8, [sp, #0x18]   ;(sp+0x18) = 28
0000000100007f1c   b      0x100007f3c

0000000100007f20   orr    w8, wzr, #0x8     ;w8 = 0x8
0000000100007f24   str    w8, [sp, #0x18]   ;(sp+0x18)=w8
0000000100007f28   b      0x100007f3c

0000000100007f2c   movz   w8, #0x9          ;w8=9
0000000100007f30   str    w8, [sp, #0x18]   ;(sp+0x18) = w8
0000000100007f34   b      0x100007f3c

0000000100007f38   str    wzr, [sp, #0x18]  ;(sp+0x18)=0  default

0000000100007f3c   ldr    w8, [sp, #0x18]   ;w8=(sp+0x18)
0000000100007f40   mov    x0, x8    
0000000100007f44   mov    x9, sp
0000000100007f48   str    x0, [x9]
0000000100007f4c   adrp   x0, #0x100007000  ;argument #1 for method imp___stubs__printf
0000000100007f50   add    x0, x0, #0xfb0   ; "b = %d\\n"
0000000100007f54   bl     imp___stubs__printf

0000000100007f58   movz   w8, #0x0
0000000100007f5c   str    w0, [sp, #0x8]
0000000100007f60   mov    x0, x8
0000000100007f64   ldp    x29, x30, [sp, #0x30]
0000000100007f68   add    sp, sp, #0x40
0000000100007f6c   ret    
                   ; endp
0000000100007f70   dd     0xffffff98, 0xffffffa4, 0xffffffb0, 0xffffffbc

四. OC代码反汇编测试

创建一个APP项目，编译的时候选择真机
OC代码

#import "AppDelegate.h"

@interface Person : NSObject
@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) NSInteger age;
- (instancetype)initWithName:(NSString *)name age:(NSInteger)age;
@end

@implementation Person

- (instancetype)initWithName:(NSString *)name age:(NSInteger)age {
    
    if (self = [super init]) {
        _name = name;
        _age = age;
    }
    return self;
}

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    [self personTestCode];
    return YES;
}

- (void)personTestCode {
    
    Person *xiaoming = [[Person alloc] initWithName:@"xiaoming" age:20];
    xiaoming.age = 21;
    Person *zhangfei = [[Person alloc] init];
    zhangfei.name = @"zhangfei";
    zhangfei.age = 24;
    
}

@end

Hopper 反汇编代码：

================ B E G I N N I N G   O F   P R O C E D U R E ================



                     -[Person initWithName:age:]:
0000000100006584         sub        sp, sp, #0x60                               ; Objective C Implementation defined at 0x1000081f8 (instance)  0x1000081f8 是数据段的地址，Person类的实现
0000000100006588         stp        x29, x30, [sp, #0x50]
000000010000658c         add        x29, sp, #0x50 ;x29=sp+0x50
0000000100006590         sub        x8, x29, #0x18 ;x8 = x29-0x18
0000000100006594         movz       x9, #0x0        ;x9 = 0
0000000100006598         stur       x0, [x29, #0xfffffff8] ;(x29+0xfffffff8) = x0
000000010000659c         stur       x1, [x29, #0xfffffff0] 
00000001000065a0         stur       x9, [x29, #0xffffffe8] 
00000001000065a4         mov        x0, x8
00000001000065a8         mov        x1, x2
00000001000065ac         str        x3, [sp, #0x18] ;(sp+0x18)=x3 传进来的age参数
00000001000065b0         bl         imp___stubs__objc_storeStrong
00000001000065b4         add        x0, sp, #0x20   ;x0 = sp+0x20
00000001000065b8         adrp       x8, #0x100008000 ;地址生成指令 代表Person(声明)这个类，和类实现地址差不多0x1000081f8
00000001000065bc         add        x8, x8, #0xe30    ; @selector(init) x8 = x8+0xe30 即：x8 = [Super init] 
00000001000065c0         adrp       x9, #0x100008000 ;x9 = Person
00000001000065c4         add        x9, x9, #0xe78  ; 0x100008e78
00000001000065c8         movz       x1, #0x0    ;x1 = 0
00000001000065cc         ldr        x2, [sp, #0x18] = x2 = (sp+0x18)
00000001000065d0         stur       x2, [x29, #0xffffffe0] ;(x29+0xffffffe0) = x2
00000001000065d4         ldur       x3, [x29, #0xfffffff8] ;(x29+0xfffffff8) = x3
00000001000065d8         stur       x1, [x29, #0xfffffff8] ;x1 = x3
00000001000065dc         str        x3, [sp, #0x20] ;(sp+0x20) = x3
00000001000065e0         ldr        x9, [x9]    ;（x9) = x9 x9指向的地址里的值，赋值x9
00000001000065e4         str        x9, [sp, #0x28] ;(sp+0x28) = x9
00000001000065e8         ldr        x1, [x8] ;x1 = (x8)
00000001000065ec         bl         imp___stubs__objc_msgSendSuper2
00000001000065f0         sub        x8, x29, #0x8 ;x8 = x29+0x8
00000001000065f4         mov        x9, x0
00000001000065f8         stur       x9, [x29, #0xfffffff8]
00000001000065fc         mov        x1, x0
0000000100006600         str        x0, [sp, #0x10]
0000000100006604         mov        x0, x8
0000000100006608         bl         imp___stubs__objc_storeStrong self = [super init] 赋值存储完成
000000010000660c         ldr        x8, [sp, #0x10]
0000000100006610         cbz        x8, 0x100006654 ;如果x8==0，跳转到0x100006654

0000000100006614         adrp       x8, #0x100008000 ;x8 = self
0000000100006618         add        x8, x8, #0xe80   ;地址 x8 = x8+0xe80=_name _OBJC_IVAR_$_Person._name
000000010000661c         ldur       x9, [x29, #0xffffffe8] ; x9 = (x29+0xffffffe8)
0000000100006620         ldur       x10, [x29, #0xfffffff8];x10 = (x29+0xfffffff8)
0000000100006624         ldrsw      x8, [x8] ;x8 = (x8) 
0000000100006628         add        x8, x10, x8 ;x8 = x10+x8
000000010000662c         mov        x0, x8 ;x0 = x8
0000000100006630         mov        x1, x9 ;x1 = x9
0000000100006634         bl         imp___stubs__objc_storeStrong 存储name完成

0000000100006638         adrp       x8, #0x100008000 ;x8=self
000000010000663c         add        x8, x8, #0xe84   ;_age = age    _OBJC_IVAR_$_Person._age
0000000100006640         ldur       x9, [x29, #0xffffffe0]
0000000100006644         ldur       x10, [x29, #0xfffffff8]
0000000100006648         ldrsw      x8, [x8]
000000010000664c         add        x8, x10, x8
0000000100006650         str        x9, [x8] 存储age完成

0000000100006654         ldur       x8, [x29, #0xfffffff8]                      ; XREF=-[Person initWithName:age:]+140
0000000100006658         mov        x0, x8
000000010000665c         bl         imp___stubs__objc_retain
0000000100006660         movz       x8, #0x0
0000000100006664         sub        x30, x29, #0x18
0000000100006668         str        x0, [sp, #0x8]
000000010000666c         mov        x0, x30
0000000100006670         mov        x1, x8
0000000100006674         bl         imp___stubs__objc_storeStrong
0000000100006678         movz       x8, #0x0
000000010000667c         sub        x0, x29, #0x8
0000000100006680         mov        x1, x8
0000000100006684         bl         imp___stubs__objc_storeStrong
0000000100006688         ldr        x0, [sp, #0x8]
000000010000668c         ldp        x29, x30, [sp, #0x50]
0000000100006690         add        sp, sp, #0x60
0000000100006694         ret        
                        ; endp


================ B E G I N N I N G   O F   P R O C E D U R E ================

                     -[AppDelegate personTestCode]:
0000000100006860         sub        sp, sp, #0x30                               ; Objective C Implementation defined at 0x100008cf0 (instance)
0000000100006864         stp        x29, x30, [sp, #0x20]
0000000100006868         add        x29, sp, #0x20
000000010000686c         adrp       x8, #0x100008000  ;x8为Person类
0000000100006870         add        x8, x8, #0xe40                              ; @selector(alloc) x8 = [Person alloc]
0000000100006874         adrp       x9, #0x100008000
0000000100006878         add        x9, x9, #0xe68                              ; objc_cls_ref_Person  x9为person对象
000000010000687c         stur       x0, [x29, #0xfffffff8]
0000000100006880         str        x1, [sp, #0x10]
0000000100006884         ldr        x9, [x9]
0000000100006888         ldr        x1, [x8]
000000010000688c         mov        x0, x9
0000000100006890         bl         imp___stubs__objc_msgSend ;调用init
0000000100006894         adrp       x8, #0x100008000
0000000100006898         add        x8, x8, #0x70                               ; @"xiaoming"  ;参数name
000000010000689c         movz       x3, #0x14 ;参数age=20
00000001000068a0         adrp       x9, #0x100008000
00000001000068a4         add        x9, x9, #0xe48                              ; @selector(initWithName:age:) ;x9为初始化方法的地址
00000001000068a8         ldr        x1, [x9]
00000001000068ac         mov        x2, x8
00000001000068b0         bl         imp___stubs__objc_msgSend ;调用initWithName:age:
00000001000068b4         movz       x2, #0x15 ; 参数x2=age=21
00000001000068b8         adrp       x8, #0x100008000
00000001000068bc         add        x8, x8, #0xe50                              ; @selector(setAge:) ;x8为setAge:方法地址
00000001000068c0         str        x0, [sp, #0x8]
00000001000068c4         ldr        x9, [sp, #0x8]
00000001000068c8         ldr        x1, [x8]
00000001000068cc         mov        x0, x9
00000001000068d0         bl         imp___stubs__objc_msgSend ;调用setAge:


00000001000068d4         adrp       x8, #0x100008000
00000001000068d8         add        x8, x8, #0xe40   ; @selector(alloc) [Person alloc]
00000001000068dc         adrp       x9, #0x100008000
00000001000068e0         add        x9, x9, #0xe68                              ; objc_cls_ref_Person
00000001000068e4         ldr        x9, [x9]
00000001000068e8         ldr        x1, [x8]
00000001000068ec         mov        x0, x9
00000001000068f0         bl         imp___stubs__objc_msgSend ;调用alloc

00000001000068f4         adrp       x8, #0x100008000
00000001000068f8         add        x8, x8, #0xe30                              ; @selector(init)
00000001000068fc         ldr        x1, [x8]
0000000100006900         bl         imp___stubs__objc_msgSend ;调用init

0000000100006904         adrp       x8, #0x100008000
0000000100006908         add        x8, x8, #0x90                               ; @"zhangfei" ;参数name
000000010000690c         adrp       x9, #0x100008000
0000000100006910         add        x9, x9, #0xe58  ; @selector(setName:) ;person setName: 方法地址
0000000100006914         str        x0, [sp]
0000000100006918         ldr        x0, [sp]
000000010000691c         ldr        x1, [x9]
0000000100006920         mov        x2, x8
0000000100006924         bl         imp___stubs__objc_msgSend ; 调用setName: 

0000000100006928         orr        x2, xzr, #0x18 ;参数age=24
000000010000692c         adrp       x8, #0x100008000
0000000100006930         add        x8, x8, #0xe50                              ; @selector(setAge:) ;setAge:方法地址
0000000100006934         ldr        x9, [sp]
0000000100006938         ldr        x1, [x8]
000000010000693c         mov        x0, x9
0000000100006940         bl         imp___stubs__objc_msgSend ;调用setAge:

0000000100006944         movz       x8, #0x0
0000000100006948         mov        x9, sp
000000010000694c         mov        x0, x9
0000000100006950         mov        x1, x8
0000000100006954         bl         imp___stubs__objc_storeStrong
0000000100006958         movz       x8, #0x0
000000010000695c         add        x9, sp, #0x8
0000000100006960         mov        x0, x9
0000000100006964         mov        x1, x8
0000000100006968         bl         imp___stubs__objc_storeStrong

000000010000696c         ldp        x29, x30, [sp, #0x20]
0000000100006970         add        sp, sp, #0x30
0000000100006974         ret        
                        ; endp

五. Xcode汇编分析


#import <Foundation/Foundation.h>

int sum(int a, int b){
    int c = 3;
    int d = 4;
    return a+b+c+d;
}

int main(int argc, const char * argv[]) {

    int a = sum(1, 2);
    printf("%d\n", a);
    
    return 0;
}

汇编代码

demo1`main:
    0x100000f40 <+0>:  pushq  %rbp     ;入栈保护bp指针
    0x100000f41 <+1>:  movq   %rsp, %rbp    ; bp指向sp
    0x100000f44 <+4>:  subq   $0x20, %rsp    ;  声明32字节的空间作为局部变量空间
    0x100000f48 <+8>:  movl   $0x1, %eax ;局部变量1给%eax寄存器
    0x100000f4d <+13>: movl   $0x2, %ecx  ;局部变量2给%ecx寄存器
    0x100000f52 <+18>: movl   $0x0, -0x4(%rbp) ;0入栈
    0x100000f59 <+25>: movl   %edi, -0x8(%rbp) ;%edi入栈
    0x100000f5c <+28>: movq   %rsi, -0x10(%rbp); %rsi入栈
    0x100000f60 <+32>: movl   %eax, %edi  ;%eax值给%edi
    0x100000f62 <+34>: movl   %ecx, %esi   ;%ecx值给%esi
    0x100000f64 <+36>: callq  0x100000f10 ; sum at main.m:11  调用sum函数
    0x100000f69 <+41>: leaq   0x3a(%rip), %rdi          ; "%d\n"
    0x100000f70 <+48>: movl   %eax, -0x14(%rbp)
->  0x100000f73 <+51>: movl   -0x14(%rbp), %esi
    0x100000f76 <+54>: movb   $0x0, %al
    0x100000f78 <+56>: callq  0x100000f8a               ; symbol stub for: printf
    0x100000f7d <+61>: xorl   %ecx, %ecx
    0x100000f7f <+63>: movl   %eax, -0x18(%rbp)
    0x100000f82 <+66>: movl   %ecx, %eax
    0x100000f84 <+68>: addq   $0x20, %rsp ;释放局部变量空间
    0x100000f88 <+72>: popq   %rbp
    0x100000f89 <+73>: retq   

demo1`sum:
    0x100000f10 <+0>:  pushq  %rbp     ;入栈保护bp指针
    0x100000f11 <+1>:  movq   %rsp, %rbp  ; bp指向sp
    0x100000f14 <+4>:  movl   %edi, -0x4(%rbp) ;将%edi的值入栈
    0x100000f17 <+7>:  movl   %esi, -0x8(%rbp) ;将%esi的值入栈
->  0x100000f1a <+10>: movl   $0x3, -0xc(%rbp) ;将局部变量3入栈
    0x100000f21 <+17>: movl   $0x4, -0x10(%rbp);将局部变量4入栈
    0x100000f28 <+24>: movl   -0x4(%rbp), %esi ;将外部参数给%esi
    0x100000f2b <+27>: addl   -0x8(%rbp), %esi; 外部参数与%esi相加后放入%esi
    0x100000f2e <+30>: addl   -0xc(%rbp), %esi ;局部变量和%esi相加后放入%esi
    0x100000f31 <+33>: addl   -0x10(%rbp), %esi  ;局部变量和%esi相加后放入%esi
    0x100000f34 <+36>: movl   %esi, %eax ;将返回值放入%eax
    0x100000f36 <+38>: popq   %rbp ;恢复bp
    0x100000f37 <+39>: retq    ;返回

引用

1. 在iOS中如何使用汇编语言

ARM汇编

一. ARM 寄存器

二. ARM汇编指令简介

三. 反汇编

四. OC代码反汇编测试

五. Xcode汇编分析

引用

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