objdump '--stop-address' option stop on a wrong ending address

[BERBAR Florian]

Hi list,

I try to extract function assembly code with objdump using
"--start-address" and "--stop-address" options but the stop address stop
on the second to last address.


Exemple : Extraction of "printf_size_info" function form "libc.so.6"

- Get "printf_size_info" function symbol address

$ objdump -T /lib/x86_64-linux-gnu/libc.so.6 | grep printf_size_info
0000000000050c40 g    DF .text  000000000000001f  GLIBC_2.2.5
printf_size_info


- Add the size of the function (4th column) to the base address of the
function (1st column) to get the ending address

0x50c40+0x1f = 0x50c5f

- Extract the function assembly code
$ objdump --start-address=0x50c40 --stop-address=0x50c5f -d
/lib/x86_64-linux-gnu/libc.so.6

/lib/x86_64-linux-gnu/libc.so.6:     format de fichier elf64-x86-64


Déassemblage de la section .text :

0000000000050c40 <printf_size_info@@GLIBC_2.2.5>:
   50c40:       48 85 f6                test   %rsi,%rsi
   50c43:       74 14                   je     50c59
<printf_size_info@@GLIBC_2.2.5+0x19>
   50c45:       0f b6 47 0c             movzbl 0xc(%rdi),%eax
   50c49:       83 e0 01                and    $0x1,%eax
   50c4c:       3c 01                   cmp    $0x1,%al
   50c4e:       19 c0                   sbb    %eax,%eax
   50c50:       30 c0                   xor    %al,%al
   50c52:       05 07 01 00 00          add    $0x107,%eax
   50c57:       89 02                   mov    %eax,(%rdx)
   50c59:       b8 01 00 00 00          mov    $0x1,%eax
   50c5e:       c3                      retq


As you can see the last address is wrong. The assembly code stop on
0x50c5e instead of 0x50c5f.


I've tried on these versions :
- "GNU objdump (GNU Binutils) 2.27" version from the official mirror
(http://ftp.gnu.org/gnu/binutils/).
- "GNU objdump (GNU Binutils for Debian) 2.25" from the offical Debian
Jessie repository.

My Linux installation is :
"3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64
GNU/Linux" Full updated.


Thank you

Florian

0x346BBA8F.asc
Description: application/pgp-keys

signature.asc
Description: OpenPGP digital signature