Why does the compiler version appear in my ELF executable?

Question

I\'ve recently compiled a simple hello world C program under Debian Linux using gcc:

gcc -mtune=native -march=native -m32 -s -Wunused -O2 -o hello hello.c
         


        

Answer 1

You can inform the loader which sections to include in your output with a linker script. You can see what sections are included in the file using the objdump command. As you've noticed there's a good bit of 'junk' in an elf - junk that is until you wish you had it.

Note though, that the size of an elf executable file is not indicative of the memory foot print of the image as realized in memory. A lot of the 'junk' isn't in the memory image and the image can call sbreak and or mmap to acquire more memory, the elf file takes no account of stack usage - essentially all of your automatic variables are unaccounted for. These are only three examples others abound.