https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88328
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kargl at gcc dot gnu.org
--- Comment #2 from kargl at gcc dot gnu.org ---
(In reply to kargl from comment #1)
> (In reply to G. Steinmetz from comment #0)
> > Affects versions down to at least gcc-5 :
> >
> >
> > $ cat z1.f90
> > program p
> > character(3), parameter :: a(0) = [character(3)::]
> > print a
> > end
> >
> >
> > $ gfortran-9-20181202 -c z1.f90
> > f951: internal compiler error: Segmentation fault
> > 0xb2ec9f crash_signal
> > ../../gcc/toplev.c:326
> > 0x63ddee resolve_tag_format
> > ../../gcc/fortran/io.c:1641
>
> I get
>
> % gfcx -c a.f90
> a.f90:3:10:
>
> 3 | print a
> | 1
> Error: FORMAT tag at (1) cannot be a zero-sized array
>
> with this patch
>
> Index: gcc/fortran/io.c
> ===================================================================
> --- gcc/fortran/io.c (revision 266710)
> +++ gcc/fortran/io.c (working copy)
> @@ -1636,6 +1636,12 @@ resolve_tag_format (gfc_expr *e)
> gfc_expr *r;
> gfc_char_t *dest, *src;
>
> + if (e->value.constructor == NULL)
> + {
> + gfc_error ("FORMAT tag at %C cannot be a zero-sized array");
> + return false;
> + }
> +
> n = 0;
> c = gfc_constructor_first (e->value.constructor);
> len = c->expr->value.character.length;
> @@ -3231,12 +3237,17 @@ gfc_resolve_dt (gfc_dt *dt, locus *loc)
> {
> gfc_expr *e;
> io_kind k;
> + locus loc_tmp;
>
> /* This is set in any case. */
> gcc_assert (dt->dt_io_kind);
> k = dt->dt_io_kind->value.iokind;
>
> + loc_tmp = gfc_current_locus;
> + gfc_current_locus = *loc;
> RESOLVE_TAG (&tag_format, dt->format_expr);
> + gfc_current_locus = loc_tmp;
> +
> RESOLVE_TAG (&tag_rec, dt->rec);
> RESOLVE_TAG (&tag_spos, dt->pos);
> RESOLVE_TAG (&tag_advance, dt->advance);
The patch is slightly wrong. RESOLVE_TAG expands to 'if () return false',
so on failure gfc_current_locus is not reset.
