Getting vptr (pointer to aka VTABLE virtual table) from the Objdump utility?

How to find out the address of VTABLEs (i.e. the corresponding vptr) using the objdump utility and the linked code. vptr is usually stored in the first byte of an object. (correct / edit this). This simple code is used with a virtual function:

class base
{
public:
    int x;
    virtual void func()
    {
        //test function

    }

};

class der : public base
{
   void func()
    {
        //test function

    }

};

/*
 * 
 */
int main() {
    int s = 9;
    base b;
    der d ;
    std::cout<<"the address of Vptr is = "<<(&b+0)<<std::endl;
    std::cout<<"the value at Vptr is = "<<(int*)*(int*)((&b+0))<<std::endl;

    return 0;
}

The following is the output of the code:

the address of Vptr is = 0x7fff86a78fe0
the value at Vptr is = **0x400c30**

Below is the main function - code disassembler :

base b;
  4009b4:   48 8d 45 d0             lea    -0x30(%rbp),%rax
  4009b8:   48 89 c7                mov    %rax,%rdi
  4009bb:   e8 f4 00 00 00          callq  400ab4 <_ZN4baseC1Ev>
    der d ;
  4009c0:   48 8d 45 c0             lea    -0x40(%rbp),%rax
  4009c4:   48 89 c7                mov    %rax,%rdi
  4009c7:   e8 fe 00 00 00          callq  400aca <_ZN3derC1Ev>

Here it is shown that _ZN4baseC1Ev is the address of the base object and _ZN3derC1Ev is the address of the derived object.

in _ZN4baseC1Ev

0000000000400ab4 <_ZN4baseC1Ev>:
  400ab4:   55                      push   %rbp
  400ab5:   48 89 e5                mov    %rsp,%rbp
  400ab8:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
  400abc:   48 8b 45 f8             mov    -0x8(%rbp),%rax
  400ac0:   48 c7 00 30 0c 40 00    movq   $0x400c30,(%rax)
  400ac7:   c9                      leaveq 
  400ac8:   c3                      retq   
  400ac9:   90                      nop

    0000000000400aca <_ZN3derC1Ev>:
        }


#include<iostream>
class base
{
public:
    int x;
    virtual void func()
  400a8a:   55                      push   %rbp
  400a8b:   48 89 e5                mov    %rsp,%rbp
  400a8e:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
    {
        //test function

    }
  400a92:   c9                      leaveq 
  400a93:   c3                      retq   

0000000000400a94 <_ZN3der4funcEv>:

};

class der : public base
{
   void func()
  400a94:   55                      push   %rbp
  400a95:   48 89 e5                mov    %rsp,%rbp
  400a98:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
    {
        //test function

    }
  400a9c:   c9                      leaveq 
  400a9d:   c3                      retq   

0000000000400a9e <_ZN4baseC2Ev>:
 */

#include <stdlib.h>
#include<iostream>
class base
{
  400a9e:   55                      push   %rbp
  400a9f:   48 89 e5                mov    %rsp,%rbp
  400aa2:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
  400aa6:   48 8b 45 f8             mov    -0x8(%rbp),%rax
  400aaa:   48 c7 00 50 0c 40 00    movq   $0x400c50,(%rax)
  400ab1:   c9                      leaveq 
  400ab2:   c3                      retq   
  400ab3:   90                      nop

0000000000400ab4 <_ZN4baseC1Ev>:
  400ab4:   55                      push   %rbp
  400ab5:   48 89 e5                mov    %rsp,%rbp
  400ab8:   48 89 7d f8             mov    %rdi,-0x8(%rbp)
  400abc:   48 8b 45 f8             mov    -0x8(%rbp),%rax
  400ac0:   48 c7 00 50 0c 40 00    movq   $0x400c50,(%rax)
  400ac7:   c9                      leaveq 
  400ac8:   c3                      retq   
  400ac9:   90                      nop

0000000000400aca <_ZN3derC1Ev>:
    }

};

Here is a link to objdump -S exe file output

also objdump -t virtualfunctionsize | grep vtable gives the following:

0000000000400c40  w    O .rodata    0000000000000018              vtable for base
0000000000601e00 g     O .dtors 0000000000000000              .hidden __DTOR_END__
0000000000400b00 g     F .text  0000000000000089              __libc_csu_init
0000000000400c20  w    O .rodata    0000000000000018              vtable for der

- VTABLE , .

• Vptr is = 0x7fff86a78fe0, - VTABLE?

• Vptr = 0x400c30. - ?

• ?

Rgds, Softy