[Bug middle-end/77696] Confusing wording for -Wformat-overflow

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77696

--- Comment #7 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
(In reply to David Malcolm from comment #6)

A tweak to this would be to show the point where the overflow occurs
(if the substring location code is up to it...):

demo.c: In function ‘test_2’:
demo.c:6:23: warning: ‘%s’ directive writing 36 bytes into a region of size 11
[-Wformat-overflow=]
     6 |   sprintf (buf, "msg: %s\n", msg);
       |            ~~~        ^~
       |            |          |
       |            |          required space: 36 bytes
       |            remaining capacity: 11 bytes
demo.c:12:11:
    12 |   test_1 ("this is long enough to cause trouble");
       |                       ^~~~~~~~~~~~~~~~~~~~~~~~~
       |                       |
       |                       overflow occurs here
demo.c:6:3: note: ‘sprintf’ output 43 bytes into a destination of size 16
     6 |   sprintf (buf, "msg: %s\n", msg);
       |            ~~~   ^~~~~~~~~
       |            |          |
       |            |          required space: 43 bytes
       |            size: 16 bytes