[bebbo]

Originally Posted by _dante_

So, very likely it means that debug information generated by gcc 6.4.1 compiler is not or could be not fully compatible with the gdb 8.2.50 debugger and to solve such compatibility issues changes on the compiler side in terms of debug information generation are required

the debug info is ok:

00000214 <_main>:
#include <stdio.h>

int main(int argc, char **argv) {
     214:       4e55 fff8       link.w a5,#-8
        puts("hello world!");
     218:       487a ffd6       pea 1f0 <___exitcpp+0x18>(pc)
     21c:       4eb9 0000 0bb0  jsr bb0 <_puts>
     222:       588f            addq.l #4,sp
        printf("argc=%ld\r\n", argc);
     224:       2f2d 0008       move.l 8(a5),-(sp)
     228:       487a ffd3       pea 1fd <___exitcpp+0x25>(pc)
     22c:       4eb9 0000 0a94  jsr a94 <_printf>
     232:       508f            addq.l #8,sp
        for (int i = 0; i < argc; ++i) {
     234:       42ad fffc       clr.l -4(a5)
     238:       6024            bra.s 25e <_main+0x4a>
                char *t = argv[i];
     23a:       202d fffc       move.l -4(a5),d0
     23e:       e588            lsl.l #2,d0
     240:       206d 000c       movea.l 12(a5),a0
     244:       d1c0            adda.l d0,a0
     246:       2b50 fff8       move.l (a0),-8(a5)
                printf("arg=%s\r\n", t);
     24a:       2f2d fff8       move.l -8(a5),-(sp)
     24e:       487a ffb8       pea 208 <___exitcpp+0x30>(pc)
     252:       4eb9 0000 0a94  jsr a94 <_printf>
     258:       508f            addq.l #8,sp
        for (int i = 0; i < argc; ++i) {
     25a:       52ad fffc       addq.l #1,-4(a5)
     25e:       202d fffc       move.l -4(a5),d0
     262:       b0ad 0008       cmp.l 8(a5),d0
     266:       6dd2            blt.s 23a <_main+0x26>
        }
        return 0;
     268:       7000            moveq #0,d0
}
     26a:       4e5d            unlk a5
     26c:       4e75            rts