On Mon, 24 Sep 2018 13:39:03 +0200
Bernhard Reutner-Fischer <rep.dot....@gmail.com> wrote:
> On Mon, 24 Sep 2018 at 13:26, Bernhard Reutner-Fischer
> <rep.dot....@gmail.com> wrote:
> >
> > Hi there.
> >
> > gfc_sym_mangled_function_id() and gfc_sym_mangled_common_id both have
> > (identical, but that's for another patch to maybe factor it out) the
> > following code for underscore handling which looks suspicious:
> >
> > ---8<---
> > static tree
> > gfc_sym_mangled_common_id (gfc_common_head *com)
> > {
> > int has_underscore;
> > const char *name;
> >
> > /* Get the name out of the common block pointer. */
> > name = com->name;
> >
> > /* If we're supposed to do a bind(c). */
> > if (com->is_bind_c && com->binding_label)
> > return maybe_get_identifier (com->binding_label);
> >
> > if (name == gfc_get_string (BLANK_COMMON_NAME))
> > return maybe_get_identifier (name);
> >
> > if (flag_underscoring)
> > {
> > has_underscore = strchr (name, '_') != 0;
> > if (flag_second_underscore && has_underscore)
> > return gfc_get_identifier("%s__", name);
> > else
> > return gfc_get_identifier("%s_", name);
> > }
> > else
> > return maybe_get_identifier (name);
> > }
> > ---8<---
> >
> > the strchr looks somewhat suspicious, IMHO:
> > Isn't what the code really wants to check the fact whether or not the
> > name *already*ends* with an underscore?
> >
> > b@h:/tmp/o$ printf "common /C/ j,i\nend" | gfortran -x f95-cpp-input -
> > -ffree-form -c -o huh.o -DC=foo && readelf -s huh.o | grep foo
> > 14: 0000000000000010 8 OBJECT GLOBAL DEFAULT COM foo_
> > b@h:/tmp/o$ printf "common /C/ j,i\nend" | gfortran -x f95-cpp-input -
> > -ffree-form -c -o huh.o -DC=foo -fsecond-underscore && readelf -s
> > huh.o | grep foo
> > 14: 0000000000000010 8 OBJECT GLOBAL DEFAULT COM foo_
> > b@h:/tmp/o$ printf "common /C/ j,i\nend" | gfortran -x f95-cpp-input -
> > -ffree-form -c -o huh.o -DC=foo_bar && readelf -s huh.o | grep foo
> > 14: 0000000000000010 8 OBJECT GLOBAL DEFAULT COM foo_bar_
> > b@h:/tmp/o$ printf "common /C/ j,i\nend" | gfortran -x f95-cpp-input -
> > -ffree-form -c -o huh.o -DC=foo_bar -fsecond-underscore && readelf -s
> > huh.o | grep foo
> > 14: 0000000000000010 8 OBJECT GLOBAL DEFAULT COM foo_bar__
> >
> > I had expected "common /foo/" with -fsecond-underscore to produce a
> > "foo__" sym, no?
> > What am i missing?
>
> I should have read the documentation of -fsecond-underscore for
> starters and maybe PR51820
> "[doc] underscoring documentation incorrect" .
>
> sorry for the noise.. :(
[i was looking for something different in my outbox but AFAICS the
above doc PR is still open, in case anyone wants to tackle it for good
anytime "soon"]
