Re: [RFA] minsyms.c: Fix switching to GNU v3 ABI

Daniel Jacobowitz
2004-03-10T16:20:12Z

On Wed, Mar 10, 2004 at 05:16:17PM +0100, Corinna Vinschen wrote:
> On Mar 10 11:04, Daniel Jacobowitz wrote:
> > > > to me like you are having a problem with leading underscores, if I
> > > > remember my sh-elf-foo correctly.
> > >
> > > Could you tell more about that? I see a big bunch of symbols beginning
> > > with "__Z". Is that what you mean?
> >
> > Yes, precisely. On sh-elf all symbols are prefixed with an underscore.
> > I've been curious for a while about where, precisely, the leading
> > underscore is supposed to get stripped before we demangle; apparently,
> > the answer is "not early enough".
>
> Ok, I think I see now what happens.
>
> There are symbols beginning with "_Z" and (the most) beginning with "__Z".
>
> The symbols beginning with "_Z" are correctly recognized as language_cplus.
>
> The symbols beginning with "__Z" are still language_auto after
> prim_record_minimal_symbol_and_info has been called, since the demangler
> in libiberty doesn't recognize them.

Wait a sec, why is that happening? Either everything should have a
leading _ or nothing should!

> In install_minimal_symbols(), line 864ff is a loop, which strips the
> first character from SYMBOL_LINKAGE_NAME, if that character equals
> get_symbol_leading_char (objfile->obfd). This leading_char is set
> to "_".
>
> So, after this loop SYMBOL_LINKAGE_NAME begins with "Z" for the first
> set of symbols (which *are* recognized as cplus variables) and with
> "_Z" for the second set of symbols (which are still auto). But now
> SYMBOL_DEMANGLED_NAME is only called for the second set of symbols
> and SYMBOL_DEMANGLED_NAME returns NULL for those symbols.
>
> What can we do?!?

Move the check earlier? It should not be necessary to change
SYMBOL_LINKAGE_NAME. I think you could do this in
prim_record_minimal_symbol_and_info at the call site of
SYMBOL_SET_NAMES.

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer