.dbug_loc is missing from binary - gcc

Question

I was inspecting ELF binary for the code mentioned below.
I compiled it on gcc 7.4.0 on Ubuntu x86_64 system in Virtual Box as :
gcc -g scratch1.c -o scratch1.out
#include <stdio.h>
void do_stuff(int my_arg){
int my_local = my_arg + 2;
int i;
for (i = 0; i < my_local; ++i) printf("i = %d\n", i);
}
int main(){
do_stuff(2);
return 0;
}
However when I tried to refer to .debug_loc section, it was empty.
objdump --dwarf=loc scratch1.out
scratch1.out: file format elf64-x86-64
Although, I do see some other debug_ sections
[26] .debug_aranges PROGBITS 0000000000000000 0000103b
0000000000000030 0000000000000000 0 0 1
[27] .debug_info PROGBITS 0000000000000000 0000106b
000000000000035f 0000000000000000 0 0 1
[28] .debug_abbrev PROGBITS 0000000000000000 000013ca
0000000000000125 0000000000000000 0 0 1
[29] .debug_line PROGBITS 0000000000000000 000014ef
00000000000000e6 0000000000000000 0 0 1
[30] .debug_str PROGBITS 0000000000000000 000015d5
00000000000002b5 0000000000000001 MS 0 0 1
Need your help why this section is missing.

Answer 1

Need your help why this section is missing.
The .debug_loc section contains DW_AT_location lists, usually emitted only for optimized code.
Since you compiled without optimization, the compiler didn't emit this section. Try building with:
gcc -g -O3 scratch1.c -o scratch1.out
Here is what I see with gcc 8.3.0:
$ gcc -g scratch.c && readelf -WS a.out | grep debug_loc
# no output
$ gcc -g scratch.c -O3 && readelf -WS a.out | grep debug_loc
[32] .debug_loc PROGBITS 0000000000000000 0039db 000230 00 0 0 1