Deteremine GCC compiler version
readelf -p .comment obj|prog can be used to determine with which GCC compiler version a program was compiled with:
$ echo 'void f() {}' | gcc -xc -c -o f.obj -
$ readelf -p .comment f.obj
String dump of section '.comment':
[ 1] GCC: (Debian 10.2.1-6) 10.2.1 20210110
$ gcc --version | head -1
gcc (Debian 10.2.1-6) 10.2.1 20210110
Alternatively, the .comment section can also be read with objdump:
$ -s -j .comment f.obj
f.obj: file format elf64-x86-64
Contents of section .comment:
0000 00474343 3a202844 65626961 6e203130 .GCC: (Debian 10
0010 2e322e31 2d362920 31302e32 2e312032 .2.1-6) 10.2.1 2
0020 30323130 31313000 0210110.