Re: DWARF64 gcc/clang flag discussion

[David Blaikie <dblaikie@gmail.com>]

On Mon, Nov 23, 2020 at 12:32 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Sat, Nov 21, 2020 at 1:21 AM mark@klomp.org <mark@klomp.org> wrote:
> >
> > On Fri, Nov 20, 2020 at 08:22:26PM +0000, Alexander Yermolovich wrote:
> > > On llvm side of compiler world there has been work done by Igor Kudrin to enable DWARF64.
> > > I am trying to add a flag to Clang to enable DWARF64 generation. https://reviews.llvm.org/D90507
> > > In review David Blaikie pointed out that there has been a discussion on what to call this flag:
> > > https://linuxplumbersconf.org/event/7/contributions/746/attachments/578/1018/DWARF5-64.pdf
> > > https://linuxplumbersconf.org/event/7/sessions/90/attachments/583/1201/dwarf-bof-notes-aug24-lpc-2020.txt
> > > https://www.mail-archive.com/gcc@gcc.gnu.org/msg92495.html
> > >
> > > Reading through that it doesn't look like there is a consensus on what it should be.
> > >
> > > From discussion there is seems to be mixed opinion if it should be
> > > -f<name> or -g<name>. Primarily centered around if -g prefix implies
> > > turning on generation of debug information.
> > >
> > > Now that LLVM can actually generate DWARF64 for ELF, can we come to consensus on the name?
> >
> > I don't believe any firm consensus was reached on naming yet.  But I
> > would pick -fdwarf32/-fdwarf64.
>
> I would pick -gdwarf32/-gdwarf64 (are we sure the DWARF spec will
> never reach version 32 or 64?
> maybe -g32 / -g64 similar to -m32/-m64 are good enough?)

Any sense of a good way to break the tie/uncertainty?

Alternatively: If Clang picks something here (likely from within this
range of candidates - though given I've got a fair bit of say on the
Clang side, and if left to me, I'd probably lean heavily on the
-fdwarf32/64 side), is it likely that choice will tend to be adopted
by GCC? I'd rather not get out of sync, but I expect a bit hard to get
a conclusion on the GCC side without patches in progress, etc. Got a
sense of who are the people who would likely be deciders/patch
approvers for such a naming choice on the GCC side?

- Dave