Mac的反编译工具一：otool （objdump工具的OSX对应工具）。
objdump的选项-S、-l十分方便。如果二进制文件中带有调试信息，可以将源代码、文件名和行号与汇编代码对应显示。
在OSX上，对应的工具是otool。与“objdump -Sl”能力接近的命令是otool -tV。
看一看insert sort算法的反编译。插入排序的一种实现：
#include
void insert_sort(int* L, int size) {
int tmp, i, j;
for (i = 1; i < size; ++i) {
tmp = L[i];
for (j = i-1; j >= 0 && L[j] > tmp; --j) {
L[j+1] = L[j];
}
L[j+1] = tmp;
}
}
void print_array(int* L, int size) {
printf("array: ");
for (int i = 0; i < size; ++i) {
printf("%d ", L[i]);
}
printf("\n");
}
int main (int argc, char** argv) {
int L[] = {18, 7, 5, 8, 99};
int size = sizeof(L) / sizeof(int);
insert_sort(L, size);
print_array(L, size);
return 0;
}
这个实现中没有全局变量，数据段（Data Section）应该没有内容。我们用"otool -dV insertsort"这个命令，只显示Data Section, 验证一下：
oliverluan@localhost:~/Documents/Opt/insertsort$ otool -dV insertsort
insertsort:如果把L数据和size变量改写成全局变量：
oliverluan@localhost:~/Documents/Opt/insertsort$ gcc -g insertsort_global.c -o insertsort_global
oliverluan@localhost:~/Documents/Opt/insertsort$ otool -dV insertsort_global
insertsort_global:
(__DATA,__data) section
0000000100001020 12 00 00 00 07 00 00 00 05 00 00 00 08 00 00 00
0000000100001030 63 00 00 00 05 00 00 00看一看Text Section： otool -tV insertsort:
oliverluan@localhost:~/Documents/Opt/insertsort$ otool -tV insertsort
insertsort:
(__TEXT,__text) section
_insert_sort:
0000000100000dd0 pushq %rbp
0000000100000dd1 movq %rsp, %rbp
0000000100000dd4 movq %rdi, 0xfffffffffffffff8(%rbp)
0000000100000dd8 movl %esi, 0xfffffffffffffff4(%rbp)
0000000100000ddb movl $0x1, 0xffffffffffffffec(%rbp)
0000000100000de2 movl 0xffffffffffffffec(%rbp), %eax
0000000100000de5 cmpl 0xfffffffffffffff4(%rbp), %eax
0000000100000de8 jge 0x100000e94
0000000100000dee movslq 0xffffffffffffffec(%rbp), %rax
0000000100000df2 movq 0xfffffffffffffff8(%rbp), %rcx
0000000100000df6 movl (%rcx,%rax,4), %edx
0000000100000df9 movl %edx, 0xfffffffffffffff0(%rbp)
0000000100000dfc movl 0xffffffffffffffec(%rbp), %edx
0000000100000dff subl $0x1, %edx
0000000100000e05 movl %edx, 0xffffffffffffffe8(%rbp)
0000000100000e08 movb $0x0, %al
0000000100000e0a cmpl $0x0, 0xffffffffffffffe8(%rbp)
0000000100000e11 movb %al, 0xffffffffffffffe7(%rbp)
0000000100000e14 jl 0x100000e30
0000000100000e1a movslq 0xffffffffffffffe8(%rbp), %rax
0000000100000e1e movq 0xfffffffffffffff8(%rbp), %rcx
0000000100000e22 movl (%rcx,%rax,4), %edx
0000000100000e25 cmpl 0xfffffffffffffff0(%rbp), %edx
0000000100000e28 setg %sil
0000000100000e2c movb %sil, 0xffffffffffffffe7(%rbp)
0000000100000e30 movb 0xffffffffffffffe7(%rbp), %al
0000000100000e33 testb $0x1, %al
0000000100000e35 jne 0x100000e40
0000000100000e3b jmpq 0x100000e6e
0000000100000e40 movslq 0xffffffffffffffe8(%rbp), %rax
0000000100000e44 movq 0xfffffffffffffff8(%rbp), %rcx
0000000100000e48 movl (%rcx,%rax,4), %edx
0000000100000e4b movl 0xffffffffffffffe8(%rbp), %esi
0000000100000e4e addl $0x1, %esi
0000000100000e54 movslq %esi, %rax
0000000100000e57 movq 0xfffffffffffffff8(%rbp), %rcx
0000000100000e5b movl %edx, (%rcx,%rax,4)
0000000100000e5e movl 0xffffffffffffffe8(%rbp), %eax
0000000100000e61 addl $0xffffffff, %eax
0000000100000e66 movl %eax, 0xffffffffffffffe8(%rbp)
0000000100000e69 jmpq 0x100000e08
0000000100000e6e movl 0xfffffffffffffff0(%rbp), %eax
0000000100000e71 movl 0xffffffffffffffe8(%rbp), %ecx
0000000100000e74 addl $0x1, %ecx
0000000100000e7a movslq %ecx, %rdx
0000000100000e7d movq 0xfffffffffffffff8(%rbp), %rsi
0000000100000e81 movl %eax, (%rsi,%rdx,4)
0000000100000e84 movl 0xffffffffffffffec(%rbp), %eax
0000000100000e87 addl $0x1, %eax
0000000100000e8c movl %eax, 0xffffffffffffffec(%rbp)
0000000100000e8f jmpq 0x100000de2
0000000100000e94 popq %rbp
0000000100000e95 ret
0000000100000e96 nopw %cs:(%rax,%rax)
_print_array:
0000000100000ea0 pushq %rbp
0000000100000ea1 movq %rsp, %rbp
0000000100000ea4 subq $0x20, %rsp
0000000100000ea8 leaq 0xdb(%rip), %rax ## literal pool for: array:
0000000100000eaf movq %rdi, 0xfffffffffffffff8(%rbp)
0000000100000eb3 movl %esi, 0xfffffffffffffff4(%rbp)
0000000100000eb6 movq %rax, %rdi
0000000100000eb9 movb $0x0, %al
0000000100000ebb callq 0x100000f68 ## symbol stub for: _printf
0000000100000ec0 movl $0x0, 0xfffffffffffffff0(%rbp)
0000000100000ec7 movl %eax, 0xffffffffffffffec(%rbp)
0000000100000eca movl 0xfffffffffffffff0(%rbp), %eax
0000000100000ecd cmpl 0xfffffffffffffff4(%rbp), %eax
0000000100000ed0 jge 0x100000f02
0000000100000ed6 leaq 0xb5(%rip), %rdi ## literal pool for: %d
0000000100000edd movslq 0xfffffffffffffff0(%rbp), %rax
0000000100000ee1 movq 0xfffffffffffffff8(%rbp), %rcx
0000000100000ee5 movl (%rcx,%rax,4), %esi
0000000100000ee8 movb $0x0, %al
0000000100000eea callq 0x100000f68 ## symbol stub for: _printf
0000000100000eef movl %eax, 0xffffffffffffffe8(%rbp)
0000000100000ef2 movl 0xfffffffffffffff0(%rbp), %eax
0000000100000ef5 addl $0x1, %eax
0000000100000efa movl %eax, 0xfffffffffffffff0(%rbp)
0000000100000efd jmpq 0x100000eca
0000000100000f02 leaq 0x8d(%rip), %rdi ## literal pool for:
0000000100000f09 movb $0x0, %al
0000000100000f0b callq 0x100000f68 ## symbol stub for: _printf
0000000100000f10 movl %eax, 0xffffffffffffffe4(%rbp)
0000000100000f13 addq $0x20, %rsp
0000000100000f17 popq %rbp
0000000100000f18 ret
0000000100000f19 nopl (%rax)
_main:
0000000100000f20 pushq %rbp
0000000100000f21 movq %rsp, %rbp
0000000100000f24 subq $0x10, %rsp
0000000100000f28 leaq _L(%rip), %rax
0000000100000f2f movl $0x0, 0xfffffffffffffffc(%rbp)
0000000100000f36 movl %edi, 0xfffffffffffffff8(%rbp)
0000000100000f39 movq %rsi, 0xfffffffffffffff0(%rbp)
0000000100000f3d movl _size(%rip), %esi
0000000100000f43 movq %rax, %rdi
0000000100000f46 callq _insert_sort
0000000100000f4b leaq _L(%rip), %rdi
0000000100000f52 movl _size(%rip), %esi
0000000100000f58 callq _print_array
0000000100000f5d movl $0x0, %eax
0000000100000f62 addq $0x10, %rsp
0000000100000f66 popq %rbp
0000000100000f67 ret另外，可以用-l选项查看load commands：
oliverluan@localhost:~/Documents/Opt/insertsort$ otool -l insertsort_global
insertsort_global:
Load command 0
cmd LC_SEGMENT_64
cmdsize 72
segname __PAGEZERO
vmaddr 0x0000000000000000
vmsize 0x0000000100000000
fileoff 0
filesize 0
maxprot 0x00000000
initprot 0x00000000
nsects 0
flags 0x0
Load command 1
cmd LC_SEGMENT_64
cmdsize 632
segname __TEXT
vmaddr 0x0000000100000000
vmsize 0x0000000000001000
fileoff 0
filesize 4096
maxprot 0x00000007
initprot 0x00000005
nsects 7
flags 0x0
Section
sectname __text
segname __TEXT
addr 0x0000000100000d60
size 0x00000000000001d9
offset 3424
align 2^4 (16)
reloff 0
nreloc 0
flags 0x80000400
reserved1 0
reserved2 0
Section
sectname __stubs
segname __TEXT
addr 0x0000000100000f3a
size 0x000000000000000c
offset 3898
align 2^1 (2)
reloff 0
nreloc 0
flags 0x80000408
reserved1 0 (index into indirect symbol table)
reserved2 6 (size of stubs)
Section
sectname __stub_helper
segname __TEXT
addr 0x0000000100000f48
size 0x0000000000000024
offset 3912
align 2^2 (4)
reloff 0
nreloc 0
flags 0x80000400
reserved1 0
reserved2 0
Section
sectname __cstring
segname __TEXT
addr 0x0000000100000f6c
size 0x000000000000000e
offset 3948
align 2^0 (1)
reloff 0
nreloc 0
flags 0x00000002
reserved1 0
reserved2 0
Section
sectname __const
segname __TEXT
addr 0x0000000100000f80
size 0x0000000000000014
offset 3968
align 2^4 (16)
reloff 0
nreloc 0
flags 0x00000000
reserved1 0
reserved2 0
Section
sectname __unwind_info
segname __TEXT
addr 0x0000000100000f94
size 0x0000000000000048
offset 3988
align 2^0 (1)
reloff 0
nreloc 0
flags 0x00000000
reserved1 0
reserved2 0
Section
sectname __eh_frame
segname __TEXT
addr 0x0000000100000fe0
size 0x0000000000000018
offset 4064
align 2^3 (8)
reloff 0
nreloc 0
flags 0x00000000
reserved1 0
reserved2 0
Load command 2
cmd LC_SEGMENT_64
cmdsize 312
segname __DATA
vmaddr 0x0000000100001000
vmsize 0x0000000000001000
fileoff 4096
filesize 4096
maxprot 0x00000007
initprot 0x00000003
nsects 3
flags 0x0
Section
sectname __nl_symbol_ptr
segname __DATA
addr 0x0000000100001000
size 0x0000000000000010
offset 4096
align 2^3 (8)
reloff 0
nreloc 0
flags 0x00000006
reserved1 2 (index into indirect symbol table)
reserved2 0
Section
sectname __got
segname __DATA
addr 0x0000000100001010
size 0x0000000000000008
offset 4112
align 2^3 (8)
reloff 0
nreloc 0
flags 0x00000006
reserved1 4 (index into indirect symbol table)
reserved2 0
Section
sectname __la_symbol_ptr
segname __DATA
addr 0x0000000100001018
size 0x0000000000000010
offset 4120
align 2^3 (8)
reloff 0
nreloc 0
flags 0x00000007
reserved1 5 (index into indirect symbol table)
reserved2 0
Load command 3
cmd LC_SEGMENT_64
cmdsize 72
segname __LINKEDIT
vmaddr 0x0000000100002000
vmsize 0x0000000000001000
fileoff 8192
filesize 916
maxprot 0x00000007
initprot 0x00000001
nsects 0
flags 0x0
Load command 4
cmd LC_DYLD_INFO_ONLY
cmdsize 48
rebase_off 8192
rebase_size 8
bind_off 8200
bind_size 56
weak_bind_off 0
weak_bind_size 0
lazy_bind_off 8256
lazy_bind_size 40
export_off 8296
export_size 80
Load command 5
cmd LC_SYMTAB
cmdsize 24
symoff 8408
nsyms 24
stroff 8820
strsize 288
Load command 6
cmd LC_DYSYMTAB
cmdsize 80
ilocalsym 0
nlocalsym 16
iextdefsym 16
nextdefsym 4
iundefsym 20
nundefsym 4
tocoff 0
ntoc 0
modtaboff 0
nmodtab 0
extrefsymoff 0
nextrefsyms 0
indirectsymoff 8792
nindirectsyms 7
extreloff 0
nextrel 0
locreloff 0
nlocrel 0
Load command 7
cmd LC_LOAD_DYLINKER
cmdsize 32
name /usr/lib/dyld (offset 12)
Load command 8
cmd LC_UUID
cmdsize 24
uuid F88FCA7D-3FE0-3556-96A4-4F29B7812D93
Load command 9
cmd LC_VERSION_MIN_MACOSX
cmdsize 16
version 10.9
sdk 10.9
Load command 10
cmd LC_SOURCE_VERSION
cmdsize 16
version 0.0
Load command 11
cmd LC_MAIN
cmdsize 24
entryoff 3760
stacksize 0
Load command 12
cmd LC_LOAD_DYLIB
cmdsize 56
name /usr/lib/libSystem.B.dylib (offset 24)
time stamp 2 Thu Jan 1 08:30:02 1970
current version 1197.1.1
compatibility version 1.0.0
Load command 13
cmd LC_FUNCTION_STARTS
cmdsize 16
dataoff 8376
datasize 8
Load command 14
cmd LC_DATA_IN_CODE
cmdsize 16
dataoff 8384
datasize 0
Load command 15
cmd LC_DYLIB_CODE_SIGN_DRS
cmdsize 16
dataoff 8384
datasize 24符号表的查看使用nm -px insertsort。-p 原始顺序，不做symbol字母或者数字排序。-x 16进制表示
oliverluan@localhost:~/Documents/Opt/insertsort$ nm -px insertsort
0000000100001020 0f 09 0000 00000000000000a9 _L
0000000100000000 0f 01 0010 00000000000000ac __mh_execute_header
0000000100000dd0 0f 01 0000 00000000000000c0 _insert_sort
0000000100000f20 0f 01 0000 00000000000000cd _main
0000000100000ea0 0f 01 0000 00000000000000d3 _print_array
0000000100001034 0f 09 0000 00000000000000e0 _size
0000000000000000 01 00 0100 00000000000000e6 _printf
0000000000000000 01 00 0100 00000000000000ee dyld_stub_binder