[a@b ~]$ mkdir compile_test
[a@b ~]$ cd compile_test/
[a@b compile_test]$ ls
[a@b compile_test]$ vi foo1.c
int foo1 = 10;
void foo1_func()
{
int ret = foo1;
}
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"foo1.c" [New] 6L, 54C written
[a@b compile_test]$ vi foo2.c
int foo2 = 20;
void foo2_func(int x)
{
int ret = foo2;
}
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"foo2.c" [New] 5L, 58C written
[a@b compile_test]$ vi hello.c
#include
extern int foo2;
int main(int argc, char *argv[])
{
foo2 = 5;
foo2_func(50);
return 0;
}
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
"hello.c" [New] 8L, 111C written
[a@b compile_test]$ gcc -S foo2.c
[a@b compile_test]$ ls
foo1.c foo2.c foo2.s hello.c
[a@b compile_test]$ cat foo2.s
.file "foo2.c"
.globl foo2
.data
.align 4
.type foo2, @object
.size foo2, 4
foo2:
.long 20
.text
.globl foo2_func
.type foo2_func, @function
foo2_func:
pushl %ebp
movl %esp, %ebp
subl $16, %esp
movl foo2, %eax
movl %eax, -4(%ebp)
leave
ret
.size foo2_func, .-foo2_func
.ident "GCC: (GNU) 4.4.6 20120305 (Red Hat 4.4.6-4)"
.section .note.GNU-stack,"",@progbits
[a@b compile_test]$ cat foo2.c
int foo2 = 20;
void foo2_func(int x)
{
int ret = foo2;
}
[a@b compile_test]$ gcc -c foo2.c foo1.c hello.c
[a@b compile_test]$ ls
foo1.c foo1.o foo2.c foo2.o foo2.s hello.c hello.o
[a@b compile_test]$ objdump -d foo2.o
foo2.o: file format elf32-i386
Disassembly of section .text:
00000000
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 83 ec 10 sub $0x10,%esp
6: a1 00 00 00 00 mov 0x0,%eax
b: 89 45 fc mov %eax,-0x4(%ebp)
e: c9 leave
f: c3 ret
[a@b compile_test]$
[a@b compile_test]$
[a@b compile_test]$ objdump -d -s foo2.o
foo2.o: file format elf32-i386
Contents of section .text:
0000 5589e583 ec10a100 00000089 45fcc9c3 U...........E...
Contents of section .data:
0000 14000000 ....
Contents of section .comment:
0000 00474343 3a202847 4e552920 342e342e .GCC: (GNU) 4.4.
0010 36203230 31323033 30352028 52656420 6 20120305 (Red
0020 48617420 342e342e 362d3429 00 Hat 4.4.6-4).
Disassembly of section .text:
00000000
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 83 ec 10 sub $0x10,%esp
6: a1 00 00 00 00 mov 0x0,%eax
b: 89 45 fc mov %eax,-0x4(%ebp)
e: c9 leave
f: c3 ret
[a@b compile_test]$ readelf -r hello.o
Relocation section '.rel.text' at offset 0x324 contains 2 entries:
Offset Info Type Sym.Value Sym. Name
0000000b 00000801 R_386_32 00000000 foo2
0000001b 00000902 R_386_PC32 00000000 foo2_func
[a@b compile_test]$
[a@b compile_test]$
[a@b compile_test]$ objdump -d hello.o
hello.o: file format elf32-i386
Disassembly of section .text:
00000000
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 83 e4 f0 and $0xfffffff0,%esp
6: 83 ec 10 sub $0x10,%esp
9: c7 05 00 00 00 00 05 movl $0x5,0x0
10: 00 00 00
13: c7 04 24 32 00 00 00 movl $0x32,(%esp)
1a: e8 fc ff ff ff call 1b
1f: b8 00 00 00 00 mov $0x0,%eax
24: c9 leave
25: c3 ret
[a@b compile_test]$ readelf -s foo2.o
Symbol table '.symtab' contains 9 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 FILE LOCAL DEFAULT ABS foo2.c
2: 00000000 0 SECTION LOCAL DEFAULT 1
3: 00000000 0 SECTION LOCAL DEFAULT 3
4: 00000000 0 SECTION LOCAL DEFAULT 4
5: 00000000 0 SECTION LOCAL DEFAULT 6
6: 00000000 0 SECTION LOCAL DEFAULT 5
7: 00000000 4 OBJECT GLOBAL DEFAULT 3 foo2
8: 00000000 16 FUNC GLOBAL DEFAULT 1 foo2_func
[a@b compile_test]$ readelf -s hello.o
Symbol table '.symtab' contains 10 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 FILE LOCAL DEFAULT ABS hello.c
2: 00000000 0 SECTION LOCAL DEFAULT 1
3: 00000000 0 SECTION LOCAL DEFAULT 3
4: 00000000 0 SECTION LOCAL DEFAULT 4
5: 00000000 0 SECTION LOCAL DEFAULT 6
6: 00000000 0 SECTION LOCAL DEFAULT 5
7: 00000000 38 FUNC GLOBAL DEFAULT 1 main
8: 00000000 0 NOTYPE GLOBAL DEFAULT UND foo2
9: 00000000 0 NOTYPE GLOBAL DEFAULT UND foo2_func
[a@b compile_test]$ gcc foo1.o foo2.o hello.o -o hello
[a@b compile_test]$ readelf -s hello
Symbol table '.dynsym' contains 4 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
2: 00000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@GLIBC_2.0 (2)
3: 0804849c 4 OBJECT GLOBAL DEFAULT 15 _IO_stdin_used
Symbol table '.symtab' contains 70 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 08048134 0 SECTION LOCAL DEFAULT 1
2: 08048148 0 SECTION LOCAL DEFAULT 2
3: 08048168 0 SECTION LOCAL DEFAULT 3
4: 0804818c 0 SECTION LOCAL DEFAULT 4
5: 080481ac 0 SECTION LOCAL DEFAULT 5
6: 080481ec 0 SECTION LOCAL DEFAULT 6
7: 08048232 0 SECTION LOCAL DEFAULT 7
8: 0804823c 0 SECTION LOCAL DEFAULT 8
9: 0804825c 0 SECTION LOCAL DEFAULT 9
10: 08048264 0 SECTION LOCAL DEFAULT 10
11: 08048274 0 SECTION LOCAL DEFAULT 11
12: 080482a4 0 SECTION LOCAL DEFAULT 12
13: 080482e0 0 SECTION LOCAL DEFAULT 13
14: 0804847c 0 SECTION LOCAL DEFAULT 14
15: 08048498 0 SECTION LOCAL DEFAULT 15
16: 080484a4 0 SECTION LOCAL DEFAULT 16
17: 080484c8 0 SECTION LOCAL DEFAULT 17
18: 08049544 0 SECTION LOCAL DEFAULT 18
19: 0804954c 0 SECTION LOCAL DEFAULT 19
20: 08049554 0 SECTION LOCAL DEFAULT 20
21: 08049558 0 SECTION LOCAL DEFAULT 21
22: 08049620 0 SECTION LOCAL DEFAULT 22
23: 08049624 0 SECTION LOCAL DEFAULT 23
24: 08049638 0 SECTION LOCAL DEFAULT 24
25: 08049644 0 SECTION LOCAL DEFAULT 25
26: 00000000 0 SECTION LOCAL DEFAULT 26
27: 00000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
28: 08049544 0 OBJECT LOCAL DEFAULT 18 __CTOR_LIST__
29: 0804954c 0 OBJECT LOCAL DEFAULT 19 __DTOR_LIST__
30: 08049554 0 OBJECT LOCAL DEFAULT 20 __JCR_LIST__
31: 08048310 0 FUNC LOCAL DEFAULT 13 __do_global_dtors_aux
32: 08049644 1 OBJECT LOCAL DEFAULT 25 completed.5972
33: 08049648 4 OBJECT LOCAL DEFAULT 25 dtor_idx.5974
34: 08048370 0 FUNC LOCAL DEFAULT 13 frame_dummy
35: 00000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
36: 08049548 0 OBJECT LOCAL DEFAULT 18 __CTOR_END__
37: 08048540 0 OBJECT LOCAL DEFAULT 17 __FRAME_END__
38: 08049554 0 OBJECT LOCAL DEFAULT 20 __JCR_END__
39: 08048450 0 FUNC LOCAL DEFAULT 13 __do_global_ctors_aux
40: 00000000 0 FILE LOCAL DEFAULT ABS foo1.c
41: 00000000 0 FILE LOCAL DEFAULT ABS foo2.c
42: 00000000 0 FILE LOCAL DEFAULT ABS hello.c
43: 08049624 0 OBJECT LOCAL DEFAULT 23 _GLOBAL_OFFSET_TABLE_
44: 08049544 0 NOTYPE LOCAL DEFAULT 18 __init_array_end
45: 08049544 0 NOTYPE LOCAL DEFAULT 18 __init_array_start
46: 08049558 0 OBJECT LOCAL DEFAULT 21 _DYNAMIC
47: 08049638 0 NOTYPE WEAK DEFAULT 24 data_start
48: 080483e0 5 FUNC GLOBAL DEFAULT 13 __libc_csu_fini
49: 080482e0 0 FUNC GLOBAL DEFAULT 13 _start
50: 00000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
51: 00000000 0 NOTYPE WEAK DEFAULT UND _Jv_RegisterClasses
52: 08048498 4 OBJECT GLOBAL DEFAULT 15 _fp_hw
53: 0804847c 0 FUNC GLOBAL DEFAULT 14 _fini
54: 08049640 4 OBJECT GLOBAL DEFAULT 24 foo2
55: 00000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@@GLIBC_
56: 0804849c 4 OBJECT GLOBAL DEFAULT 15 _IO_stdin_used
57: 08049638 0 NOTYPE GLOBAL DEFAULT 24 __data_start
58: 080484a0 0 OBJECT GLOBAL HIDDEN 15 __dso_handle
59: 08049550 0 OBJECT GLOBAL HIDDEN 19 __DTOR_END__
60: 080483f0 90 FUNC GLOBAL DEFAULT 13 __libc_csu_init
61: 08049644 0 NOTYPE GLOBAL DEFAULT ABS __bss_start
62: 080483a4 16 FUNC GLOBAL DEFAULT 13 foo2_func
63: 0804964c 0 NOTYPE GLOBAL DEFAULT ABS _end
64: 08049644 0 NOTYPE GLOBAL DEFAULT ABS _edata
65: 0804963c 4 OBJECT GLOBAL DEFAULT 24 foo1
66: 0804844a 0 FUNC GLOBAL HIDDEN 13 __i686.get_pc_thunk.bx
67: 080483b4 38 FUNC GLOBAL DEFAULT 13 main
68: 08048274 0 FUNC GLOBAL DEFAULT 11 _init
69: 08048394 16 FUNC GLOBAL DEFAULT 13 foo1_func
[a@b compile_test]$
[a@b compile_test]$ readelf -S hello
There are 30 section headers, starting at offset 0x798:
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .interp PROGBITS 08048134 000134 000013 00 A 0 0 1
[ 2] .note.ABI-tag NOTE 08048148 000148 000020 00 A 0 0 4
[ 3] .note.gnu.build-i NOTE 08048168 000168 000024 00 A 0 0 4
[ 4] .gnu.hash GNU_HASH 0804818c 00018c 000020 04 A 5 0 4
[ 5] .dynsym DYNSYM 080481ac 0001ac 000040 10 A 6 1 4
[ 6] .dynstr STRTAB 080481ec 0001ec 000045 00 A 0 0 1
[ 7] .gnu.version VERSYM 08048232 000232 000008 02 A 5 0 2
[ 8] .gnu.version_r VERNEED 0804823c 00023c 000020 00 A 6 1 4
[ 9] .rel.dyn REL 0804825c 00025c 000008 08 A 5 0 4
[10] .rel.plt REL 08048264 000264 000010 08 A 5 12 4
[11] .init PROGBITS 08048274 000274 000030 00 AX 0 0 4
[12] .plt PROGBITS 080482a4 0002a4 000030 04 AX 0 0 4
[13] .text PROGBITS 080482e0 0002e0 00019c 00 AX 0 0 16
[14] .fini PROGBITS 0804847c 00047c 00001c 00 AX 0 0 4
[15] .rodata PROGBITS 08048498 000498 00000c 00 A 0 0 4
[16] .eh_frame_hdr PROGBITS 080484a4 0004a4 000024 00 A 0 0 4
[17] .eh_frame PROGBITS 080484c8 0004c8 00007c 00 A 0 0 4
[18] .ctors PROGBITS 08049544 000544 000008 00 WA 0 0 4
[19] .dtors PROGBITS 0804954c 00054c 000008 00 WA 0 0 4
[20] .jcr PROGBITS 08049554 000554 000004 00 WA 0 0 4
[21] .dynamic DYNAMIC 08049558 000558 0000c8 08 WA 6 0 4
[22] .got PROGBITS 08049620 000620 000004 04 WA 0 0 4
[23] .got.plt PROGBITS 08049624 000624 000014 04 WA 0 0 4
[24] .data PROGBITS 08049638 000638 00000c 00 WA 0 0 4
[25] .bss NOBITS 08049644 000644 000008 00 WA 0 0 4
[26] .comment PROGBITS 00000000 000644 000058 01 MS 0 0 1
[27] .shstrtab STRTAB 00000000 00069c 0000fc 00 0 0 1
[28] .symtab SYMTAB 00000000 000c48 000460 10 29 47 4
[29] .strtab STRTAB 00000000 0010a8 000217 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
[a@b compile_test]$ readelf -s hello | grep foo2
41: 00000000 0 FILE LOCAL DEFAULT ABS foo2.c
54: 08049640 4 OBJECT GLOBAL DEFAULT 24 foo2
62: 080483a4 16 FUNC GLOBAL DEFAULT 13 foo2_func
[a@b compile_test]$ readelf -d hello
Dynamic section at offset 0x558 contains 20 entries:
Tag Type Name/Value
0x00000001 (NEEDED) Shared library: [libc.so.6]
0x0000000c (INIT) 0x8048274
0x0000000d (FINI) 0x804847c
0x6ffffef5 (GNU_HASH) 0x804818c
0x00000005 (STRTAB) 0x80481ec
0x00000006 (SYMTAB) 0x80481ac
0x0000000a (STRSZ) 69 (bytes)
0x0000000b (SYMENT) 16 (bytes)
0x00000015 (DEBUG) 0x0
0x00000003 (PLTGOT) 0x8049624
0x00000002 (PLTRELSZ) 16 (bytes)
0x00000014 (PLTREL) REL
0x00000017 (JMPREL) 0x8048264
0x00000011 (REL) 0x804825c
0x00000012 (RELSZ) 8 (bytes)
0x00000013 (RELENT) 8 (bytes)
0x6ffffffe (VERNEED) 0x804823c
0x6fffffff (VERNEEDNUM) 1
0x6ffffff0 (VERSYM) 0x8048232
0x00000000 (NULL) 0x0
[a@b compile_test]$ objdump -d hello
hello: file format elf32-i386
Disassembly of section .init:
08048274 <_init>:
8048274: 55 push %ebp
8048275: 89 e5 mov %esp,%ebp
8048277: 53 push %ebx
8048278: 83 ec 04 sub $0x4,%esp
804827b: e8 00 00 00 00 call 8048280 <_init+0xc>
8048280: 5b pop %ebx
8048281: 81 c3 a4 13 00 00 add $0x13a4,%ebx
8048287: 8b 93 fc ff ff ff mov -0x4(%ebx),%edx
804828d: 85 d2 test %edx,%edx
804828f: 74 05 je 8048296 <_init+0x22>
8048291: e8 1e 00 00 00 call 80482b4 <__gmon_start__@plt>
8048296: e8 d5 00 00 00 call 8048370
804829b: e8 b0 01 00 00 call 8048450 <__do_global_ctors_aux>
80482a0: 58 pop %eax
80482a1: 5b pop %ebx
80482a2: c9 leave
80482a3: c3 ret
Disassembly of section .plt:
080482a4 <__gmon_start__@plt-0x10>:
80482a4: ff 35 28 96 04 08 pushl 0x8049628
80482aa: ff 25 2c 96 04 08 jmp *0x804962c
80482b0: 00 00 add %al,(%eax)
...
080482b4 <__gmon_start__@plt>:
80482b4: ff 25 30 96 04 08 jmp *0x8049630
80482ba: 68 00 00 00 00 push $0x0
80482bf: e9 e0 ff ff ff jmp 80482a4 <_init+0x30>
080482c4 <__libc_start_main@plt>:
80482c4: ff 25 34 96 04 08 jmp *0x8049634
80482ca: 68 08 00 00 00 push $0x8
80482cf: e9 d0 ff ff ff jmp 80482a4 <_init+0x30>
Disassembly of section .text:
080482e0 <_start>:
80482e0: 31 ed xor %ebp,%ebp
80482e2: 5e pop %esi
80482e3: 89 e1 mov %esp,%ecx
80482e5: 83 e4 f0 and $0xfffffff0,%esp
80482e8: 50 push %eax
80482e9: 54 push %esp
80482ea: 52 push %edx
80482eb: 68 e0 83 04 08 push $0x80483e0
80482f0: 68 f0 83 04 08 push $0x80483f0
80482f5: 51 push %ecx
80482f6: 56 push %esi
80482f7: 68 b4 83 04 08 push $0x80483b4
80482fc: e8 c3 ff ff ff call 80482c4 <__libc_start_main@plt>
8048301: f4 hlt
8048302: 90 nop
8048303: 90 nop
8048304: 90 nop
8048305: 90 nop
8048306: 90 nop
8048307: 90 nop
8048308: 90 nop
8048309: 90 nop
804830a: 90 nop
804830b: 90 nop
804830c: 90 nop
804830d: 90 nop
804830e: 90 nop
804830f: 90 nop
08048310 <__do_global_dtors_aux>:
8048310: 55 push %ebp
8048311: 89 e5 mov %esp,%ebp
8048313: 53 push %ebx
8048314: 8d 64 24 fc lea -0x4(%esp),%esp
8048318: 80 3d 44 96 04 08 00 cmpb $0x0,0x8049644
804831f: 75 3e jne 804835f <__do_global_dtors_aux+0x4f>
8048321: bb 50 95 04 08 mov $0x8049550,%ebx
8048326: a1 48 96 04 08 mov 0x8049648,%eax
804832b: 81 eb 4c 95 04 08 sub $0x804954c,%ebx
8048331: c1 fb 02 sar $0x2,%ebx
8048334: 83 eb 01 sub $0x1,%ebx
8048337: 39 d8 cmp %ebx,%eax
8048339: 73 1d jae 8048358 <__do_global_dtors_aux+0x48>
804833b: 90 nop
804833c: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi
8048340: 83 c0 01 add $0x1,%eax
8048343: a3 48 96 04 08 mov %eax,0x8049648
8048348: ff 14 85 4c 95 04 08 call *0x804954c(,%eax,4)
804834f: a1 48 96 04 08 mov 0x8049648,%eax
8048354: 39 d8 cmp %ebx,%eax
8048356: 72 e8 jb 8048340 <__do_global_dtors_aux+0x30>
8048358: c6 05 44 96 04 08 01 movb $0x1,0x8049644
804835f: 8d 64 24 04 lea 0x4(%esp),%esp
8048363: 5b pop %ebx
8048364: 5d pop %ebp
8048365: c3 ret
8048366: 8d 76 00 lea 0x0(%esi),%esi
8048369: 8d bc 27 00 00 00 00 lea 0x0(%edi,%eiz,1),%edi
08048370
8048370: 55 push %ebp
8048371: 89 e5 mov %esp,%ebp
8048373: 8d 64 24 e8 lea -0x18(%esp),%esp
8048377: a1 54 95 04 08 mov 0x8049554,%eax
804837c: 85 c0 test %eax,%eax
804837e: 74 12 je 8048392
8048380: b8 00 00 00 00 mov $0x0,%eax
8048385: 85 c0 test %eax,%eax
8048387: 74 09 je 8048392
8048389: c7 04 24 54 95 04 08 movl $0x8049554,(%esp)
8048390: ff d0 call *%eax
8048392: c9 leave
8048393: c3 ret
08048394
8048394: 55 push %ebp
8048395: 89 e5 mov %esp,%ebp
8048397: 83 ec 10 sub $0x10,%esp
804839a: a1 3c 96 04 08 mov 0x804963c,%eax
804839f: 89 45 fc mov %eax,-0x4(%ebp)
80483a2: c9 leave
80483a3: c3 ret
080483a4
80483a4: 55 push %ebp
80483a5: 89 e5 mov %esp,%ebp
80483a7: 83 ec 10 sub $0x10,%esp
80483aa: a1 40 96 04 08 mov 0x8049640,%eax
80483af: 89 45 fc mov %eax,-0x4(%ebp)
80483b2: c9 leave
80483b3: c3 ret
080483b4
80483b4: 55 push %ebp
80483b5: 89 e5 mov %esp,%ebp
80483b7: 83 e4 f0 and $0xfffffff0,%esp
80483ba: 83 ec 10 sub $0x10,%esp
80483bd: c7 05 40 96 04 08 05 movl $0x5,0x8049640
80483c4: 00 00 00
80483c7: c7 04 24 32 00 00 00 movl $0x32,(%esp)
80483ce: e8 d1 ff ff ff call 80483a4
80483d3: b8 00 00 00 00 mov $0x0,%eax
80483d8: c9 leave
80483d9: c3 ret
80483da: 90 nop
80483db: 90 nop
80483dc: 90 nop
80483dd: 90 nop
80483de: 90 nop
80483df: 90 nop
080483e0 <__libc_csu_fini>:
80483e0: 55 push %ebp
80483e1: 89 e5 mov %esp,%ebp
80483e3: 5d pop %ebp
80483e4: c3 ret
80483e5: 66 66 2e 0f 1f 84 00 data32 nopw %cs:0x0(%eax,%eax,1)
80483ec: 00 00 00 00
080483f0 <__libc_csu_init>:
80483f0: 55 push %ebp
80483f1: 89 e5 mov %esp,%ebp
80483f3: 57 push %edi
80483f4: 56 push %esi
80483f5: 53 push %ebx
80483f6: e8 4f 00 00 00 call 804844a <__i686.get_pc_thunk.bx>
80483fb: 81 c3 29 12 00 00 add $0x1229,%ebx
8048401: 83 ec 1c sub $0x1c,%esp
8048404: e8 6b fe ff ff call 8048274 <_init>
8048409: 8d bb 20 ff ff ff lea -0xe0(%ebx),%edi
804840f: 8d 83 20 ff ff ff lea -0xe0(%ebx),%eax
8048415: 29 c7 sub %eax,%edi
8048417: c1 ff 02 sar $0x2,%edi
804841a: 85 ff test %edi,%edi
804841c: 74 24 je 8048442 <__libc_csu_init+0x52>
804841e: 31 f6 xor %esi,%esi
8048420: 8b 45 10 mov 0x10(%ebp),%eax
8048423: 89 44 24 08 mov %eax,0x8(%esp)
8048427: 8b 45 0c mov 0xc(%ebp),%eax
804842a: 89 44 24 04 mov %eax,0x4(%esp)
804842e: 8b 45 08 mov 0x8(%ebp),%eax
8048431: 89 04 24 mov %eax,(%esp)
8048434: ff 94 b3 20 ff ff ff call *-0xe0(%ebx,%esi,4)
804843b: 83 c6 01 add $0x1,%esi
804843e: 39 fe cmp %edi,%esi
8048440: 72 de jb 8048420 <__libc_csu_init+0x30>
8048442: 83 c4 1c add $0x1c,%esp
8048445: 5b pop %ebx
8048446: 5e pop %esi
8048447: 5f pop %edi
8048448: 5d pop %ebp
8048449: c3 ret
0804844a <__i686.get_pc_thunk.bx>:
804844a: 8b 1c 24 mov (%esp),%ebx
804844d: c3 ret
804844e: 90 nop
804844f: 90 nop
08048450 <__do_global_ctors_aux>:
8048450: 55 push %ebp
8048451: 89 e5 mov %esp,%ebp
8048453: 53 push %ebx
8048454: 8d 64 24 fc lea -0x4(%esp),%esp
8048458: a1 44 95 04 08 mov 0x8049544,%eax
804845d: 83 f8 ff cmp $0xffffffff,%eax
8048460: 74 12 je 8048474 <__do_global_ctors_aux+0x24>
8048462: bb 44 95 04 08 mov $0x8049544,%ebx
8048467: 90 nop
8048468: 8d 5b fc lea -0x4(%ebx),%ebx
804846b: ff d0 call *%eax
804846d: 8b 03 mov (%ebx),%eax
804846f: 83 f8 ff cmp $0xffffffff,%eax
8048472: 75 f4 jne 8048468 <__do_global_ctors_aux+0x18>
8048474: 8d 64 24 04 lea 0x4(%esp),%esp
8048478: 5b pop %ebx
8048479: 5d pop %ebp
804847a: c3 ret
804847b: 90 nop
Disassembly of section .fini:
0804847c <_fini>:
804847c: 55 push %ebp
804847d: 89 e5 mov %esp,%ebp
804847f: 53 push %ebx
8048480: 83 ec 04 sub $0x4,%esp
8048483: e8 00 00 00 00 call 8048488 <_fini+0xc>
8048488: 5b pop %ebx
8048489: 81 c3 9c 11 00 00 add $0x119c,%ebx
804848f: e8 7c fe ff ff call 8048310 <__do_global_dtors_aux>
8048494: 59 pop %ecx
8048495: 5b pop %ebx
8048496: c9 leave
8048497: c3 ret
[a@b compile_test]$ gcc -shared -fPIC foo1.c foo2.c -o libfoo.so
[a@b compile_test]$ gcc hello.c -o hello -L./ -lfoo
[a@b compile_test]$ readelf -d hello | grep Shared
0x00000001 (NEEDED) Shared library: [libfoo.so]
0x00000001 (NEEDED) Shared library: [libc.so.6]
[a@b compile_test]$ readelf -r hello
Relocation section '.rel.dyn' at offset 0x35c contains 2 entries:
Offset Info Type Sym.Value Sym. Name
08049728 00000106 R_386_GLOB_DAT 00000000 __gmon_start__
08049748 00000705 R_386_COPY 08049748 foo2
Relocation section '.rel.plt' at offset 0x36c contains 3 entries:
Offset Info Type Sym.Value Sym. Name
08049738 00000107 R_386_JUMP_SLOT 00000000 __gmon_start__
0804973c 00000307 R_386_JUMP_SLOT 00000000 __libc_start_main
08049740 00000407 R_386_JUMP_SLOT 00000000 foo2_func
[a@b compile_test]$