How to use objdump with --disassemble=

Question

Here is a simple cpp file:

#include <iostream>

void test(int x)
{
  std::cout << "x is " << x << std::endl;
}

int main()
{
  test(5);

  return 0;
}

After compiling with g++, suppose I want to use objdump to show the disassembly only of the test function (not main):

objdump a.out --disassemble="test"

The resulting disassembly is empty, evidently because objdump failed to find the symbol "test". If instead I use -t to show the symbol table, I can see the symbol I'm looking for:

objdump -t a.out | grep test
0000000000000000 l    df *ABS*  0000000000000000              test4.cpp
0000000000001285 l     F .text  0000000000000019              _GLOBAL__sub_I__Z4testi
00000000000011c9 g     F .text  000000000000004d              _Z4testi

Using _Z4testi instead of test in the original objdump command now works:

objdump a.out --disassemble="_Z4testi"
...
Disassembly of section .text:

00000000000011c9 <_Z4testi>:
    11c9:       f3 0f 1e fa             endbr64 
    11cd:       55                      push   %rbp
    11ce:       48 89 e5                mov    %rsp,%rbp
    11d1:       48 83 ec 10             sub    $0x10,%rsp
...

Is there a way, for convenience, to make --disassemble accept the unmangled symbol name?

g++ (Ubuntu 11.3.0-1ubuntu1~22.04.1) 11.3.0

GNU objdump (GNU Binutils for Ubuntu) 2.38

How to use objdump with --disassemble=

0 Answers0