-fomit-frame-pointer 编译选项在gcc 4.8.2版本中的汇编代码研究

#include
void fun(void) { printf("fun"); }
int main(int argc, char *argv[]){ fun(); return 0;}

$ gcc -o test_ffp test.c                                $ gcc -fomit-frame-pointer -o test_ffp test.c
-rwxr-xr-x 1 Admin 40968 Jan 23 21:14 test.exe          -rwxr-xr-x 1 Admin 40968 Jan 23 21:22 test_ffp.exe
$ gdb -q test.exe                                       $ gdb -q test_ffp.exe
(gdb) disass main                                       (gdb) disass main
Dump of assembler code for \
--ction main:               Dump of assembler code for \
--ction main:
   0x00401574 :     push   %ebp                        0x00401573 :     push   %ebp
   0x00401575 :     mov    %esp,%ebp                   0x00401574 :     mov    %esp,%ebp
   0x00401577 :     and    $0xfffffff0,%esp            0x00401576 :     and    $0xfffffff0,%esp
   0x0040157a :     call   0x401fb0            0x00401579 :     call   0x401fb0
   0x0040157f :    call   0x401560                    0x0040157e :    call   0x401560
   0x00401584 :    mov    $0x0,%eax                   0x00401583 :    mov    $0x0,%eax
   0x00401589 :    leave                              0x00401588 :    leave
   0x0040158a :    ret                                0x00401589 :    ret
   0x0040158b :    nop                                0x0040158a :    nop
   0x0040158c :    xchg   %ax,%ax                     0x0040158b :    nop
   0x0040158e :    xchg   %ax,%ax                     0x0040158c :    xchg   %ax,%ax
End of assembler dump.                                  End of assembler dump.   

(gdb) disass fun                                         (gdb) disass fun
Dump of assembler code for \
--ction fun:                 Dump of assembler code for \
--ction fun:
   0x00401560 :     push   %ebp                        0x00401560 :     sub    $0x1c,%esp
   0x00401561 :     mov    %esp,%ebp                   0x00401563 :     movl   $0x404024,(%esp)
   0x00401563 :     sub    $0x18,%esp                  0x0040156a :    call   0x402738
   0x00401566 :     movl   $0x404024,(%esp)            0x0040156f :    add    $0x1c,%esp
   0x0040156d :    call   0x402738                    0x00401572 :    ret
   0x00401572 :    leave                           End of assembler dump.
   0x00401573 :    ret                             (gdb)
End of assembler dump.
(gdb)

文件大小是一样,结果fun函数的汇编代码中push %ebp; leave; 没有啦.