[parisc-linux] Re: [RFC] Emit OPD reloc for all global symbols and then some.

[H. J. Lu]

On Mon, Jun 20, 2005 at 05:29:13PM -0400, Carlos O'Donell wrote:
> On Mon, Jun 20, 2005 at 01:40:56PM -0700, H. J. Lu wrote:
> > On Mon, Jun 20, 2005 at 04:26:25PM -0400, John David Anglin wrote:
> > > > > Under hppa-linux:
> > > > > ------------------
> > > > > We want to generate a PLABEL32 (OPD reloc) against all global symbols,
> > > > > and then some. For example it should be possible for an application to
> > > > > call dlsym asking for the address of main, and when compared to main it
> > > > > should match.
> > > > > 
> > > > 
> > > > Does it work on Linux/ia32? If not, why should it work on Linux/hppa?
> > > 
> > > The linux manpage for dlsym indicates that symbols in the main
> > > program can be looked up with dlsym:
> > > 
> > >      If filename is a NULL pointer, then the returned handle is
> > >      for the main program.  When given to dlsym(), this  handle
> > >      causes a search for a symbol in the main program, followed
> > >      by all shared libraries loaded  at  program  startup,  and
> > >      then all shared libraries loaded by dlopen() with the flag
> > >      RTLD_GLOBAL.
> > > 
> > > So, if it doesn't work, that would seem to be a bug in Linux/ia32.
> > 
> > It works if the global symbol is exported. But not all global symbols
> > in main are exported by default. You can use --export-dynamic to export
> > all global symbols.
> 
> Regardless of wether or not I export all global symbols in main, I must
> still emit OPD relocs in the executable for all dynamic symbols. In the
						^^^^^^^^^^

Did you mean dynamic or global? There is a big difference. In your
proposal, you said "We want to generate a PLABEL32 (OPD reloc) against
all global symbols,". I am not familiar with HPPA. I just want to know
what you have in mind.

> past the OPD reloc was "fudged" and pointed at the PLT, and this is not
> a satisfactory situation. I want ld.so.1 to generate the OPD so we no
> longer need gcc to emit the __cffc helper function for comparisons.


H.J.