V2 [PATCH] as: Automatically enable DWARF5 support

[H.J. Lu]

On Mon, Jan 18, 2021 at 5:36 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Sun, Jan 17, 2021 at 9:57 PM Alan Modra <amodra@gmail.com> wrote:
> >
> > On Sun, Jan 17, 2021 at 08:00:25AM -0800, H.J. Lu via Binutils wrote:
> > > How about this patch to automatically enable DWARF5 support?
> >
> > > diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
> > > index a428370ecca..6c9871cb300 100644
> > > --- a/gas/dwarf2dbg.c
> > > +++ b/gas/dwarf2dbg.c
> > > @@ -551,7 +551,7 @@ dwarf2_gen_line_info (addressT ofs, struct dwarf2_line_info *loc)
> > >    if (loc->line == 0)
> > >      return;
> > >    if (loc->filenum == 0 && DWARF2_LINE_VERSION < 5)
> > > -    return;
> > > +    dwarf_level = 5;
> > >
> > >    /* Don't emit sequences of line symbols for the same line when the
> > >       symbols apply to assembler code.  It is necessary to emit
> >
> > A target may override the default DWARF2_LINE_VERSION, so I think you
> > should write something like
> >
> >   if (loc->filenum == 0 && dwarf_level < 5)
> >     dwarf_level = 5;
> >   if (loc->filenum == 0 && DWARF2_LINE_VERSION < 5)
> >     return;
>
> Fixed.
>
> >
> > > @@ -1043,11 +1043,7 @@ dwarf2_directive_filename (void)
> > >    num = get_absolute_expression ();
> > >
> > >    if ((offsetT) num < 1 && DWARF2_LINE_VERSION < 5)
> > > -    {
> > > -      as_bad (_("file number less than one"));
> > > -      ignore_rest_of_line ();
> > > -      return NULL;
> > > -    }
> > > +    dwarf_level = 5;
> > >
> > >    /* FIXME: Should we allow ".file <N>\n" as an expression meaning
> > >       "switch back to the already allocated file <N> as the current
> >
> > Similarly here, and in any case we shouldn't ignore a negative file
> > number.  This should be
>
> Fixed.
>
> >   if (num == 0 && dwarf_level < 5)
> >     dwarf_level = 5;
> >   if ((offsetT) num < 0 || (num != 0 && DWARF2_LINE_VERSION < 5))
> >     {
> >       as_bad (_("file number less than one"));
> >       ignore_rest_of_line ();
> >       return NULL;
> >     }
> >
> > > @@ -1142,10 +1138,7 @@ dwarf2_directive_loc (int dummy ATTRIBUTE_UNUSED)
> > >    if (filenum < 1)
> > >      {
> > >        if (filenum != 0 || DWARF2_LINE_VERSION < 5)
> > > -     {
> > > -       as_bad (_("file number less than one"));
> > > -       return;
> > > -     }
> > > +     dwarf_level = 5;
> > >      }
> > >
> > >    if (filenum >= (int) files_in_use || files[filenum].filename == NULL)
> >
> > Similarly.
> >
>
> Fixed.
>
> Here is the updated patch.   OK for master?
>

Nick approved my patch at

https://sourceware.org/bugzilla/show_bug.cgi?id=27195#c7

I am checking it in.  Is it OK to backport to 2.36 branch?

Thanks.

-- 
H.J.