ELF linker is broken

["H. J. Lu" <hjl at lucon dot org>]

On Mon, Jan 31, 2005 at 05:43:08PM +1030, Alan Modra wrote:
> On Mon, Jan 31, 2005 at 10:32:27AM +1030, Alan Modra wrote:
> > On Sun, Jan 30, 2005 at 11:22:49AM -0800, H. J. Lu wrote:
> > > /usr/lib/crt1.o:(.dynamic+0x0): multiple definition of `_DYNAMIC'
> > [snip]
> > > The 2005-01-24 binutils is OK. It may have something to do with
> > > 
> > > http://sources.redhat.com/ml/binutils/2005-01/msg00405.html
> > 
> > Possible, I suppose.  An as-needed shared lib will define syms whether
> > or not the lib is actually linked.  It will be linked if any symbol it
> > defines satisfies an undefined reference, and conversely it isn't linked
> > then there are no references to its symbols.  That should make it safe
> > to leave its symbols in the symbol table, so long as we properly treat
> > them in _bfd_elf_merge_symbol.  If there is a problem, it's likely to be
> > in _bfd_elf_merge_symbol.
> 
> I'm testing the following on powerpc and x86 to ensure I haven't made
> any silly mistakes.  It's a big hammer approach but cleaner than what we
> had before, I think.  Rather than tweaking _bfd_elf_merge_symbol and
> other places to specially handle symbols defined in unused --as-needed
> libs, I've munged all such symbols back to their new state.  Hopefully
> this won't break too many back-end elf_link_hash_traverse functions..
> 
> Would you please test this on ia64?  I don't have access to ia64
> hardware, so testing this isn't so easy.

I am enclosing a testcase here. I saw the same problem on ia32, ia64
and x86_64:

[hjl@gnu-4 needed]$ make
gcc    -c -o foo.o foo.c
gcc -shared -fPIC -o libneeded.so needed.c
gcc -o foo foo.o \
        -Wl,--as-needed -lneeded -L. -Wl,--no-as-needed
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/../../../crt1.o:(.dynamic+0x0):
multiple definition of `_DYNAMIC'
collect2: ld returned 1 exit status
make: *** [foo] Error 1


H.J.

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