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Re: [RFC] Providing init_fini_syms earlier?
On Thu, Jul 07, 2005 at 09:32:35PM -0700, H. J. Lu wrote:
> On Thu, Jul 07, 2005 at 10:58:57PM -0400, Carlos O'Donell wrote:
> > > 2. __init_array_start/__init_array_end are provided by linker for
> > > static exexcutables since DT_INIT_ARRAY isn't available.
> >
> > Linking a dynamic executable adds libc_nonshared.a, which has undefined
> > references to __init_array_start and associated symbols.
> >
> > It looks to me that the linker provides these symbols in all links,
> > wether static or dynamic executables.
> >
> > In the later case, because the linker provides the symbol so late, it's
> > impossible to know if I should or shouldn't allocate space. Space is
> > allocated, and after the section sizes have been fixed, the linker
> > provides the symbols. At this point we know we don't need them, and we
> > don't emit a relocation. However, we can no longer resize the section.
> >
>
> I have
>
> bash-3.00$ readelf -s /usr/lib/libc_nonshared.a| grep _array_
> 5: 00000000 0 NOTYPE GLOBAL HIDDEN UND __preinit_array_start
> 6: 00000000 0 NOTYPE GLOBAL HIDDEN UND __preinit_array_end
> 7: 00000000 0 NOTYPE GLOBAL HIDDEN UND __init_array_start
> 8: 00000000 0 NOTYPE GLOBAL HIDDEN UND __init_array_end
> 9: 00000000 0 NOTYPE GLOBAL HIDDEN UND __fini_array_start
> 10: 00000000 0 NOTYPE GLOBAL HIDDEN UND __fini_array_end
>
> What do you have?
carlos@firin:~$ readelf -s /usr/lib/libc_nonshared.a| grep _array_
9: 00000000 0 NOTYPE GLOBAL DEFAULT UND __init_array_end
10: 00000000 0 NOTYPE GLOBAL DEFAULT UND __init_array_start
13: 00000000 0 NOTYPE GLOBAL DEFAULT UND __fini_array_end
14: 00000000 0 NOTYPE GLOBAL DEFAULT UND __fini_array_start
This depends largely on the version of libc installed (2.3.2 debian).
The newer versions have "attribute_hidden" while 2.3.2 does not.
c.