[Bug target/24718] Shared libgcc not used for linking by default

[wilson at gcc dot gnu dot org]

------- Comment #7 from wilson at gcc dot gnu dot org  2005-11-09 01:45 -------
I see the problem now.  It is present in the FSF gcc-3.4.x sources.

The problem is that init_gcc_specs in gcc.c rewrites the LIBGCC_SPEC rule.  It
looks for the first -lgcc, and replaces it with target independent rules for
shared and static libgcc.

The config/ia64/hpux.h file redefines LIBGCC_SPEC as 
#define LIBGCC_SPEC \
  "%{shared-libgcc:%{!mlp64:-lgcc_s}%{mlp64:-lgcc_s_hpux64} -lgcc} \
   %{!shared-libgcc:-lgcc}"

So after the substitution, we now have %{shared-libgcc ... %{static-libgcc
...}} which is obviously wrong.

If the config/ia64/hpux.h file is changed to look something like
#define LIBGCC_SPEC \
  "%{shared-libgcc:%{!mlp64:-lgcc_s}%{mlp64:-lgcc_s_hpux64}} -lgcc"
then it will work much better.  I think this can be simplified further without
loss of functionality to
#define LIBGCC_SPEC \
  "%{shared-libgcc:%{mlp64:-lgcc_s_hpux64}} -lgcc"
The important part here is that -lgcc must not appear inside any braces,
because it will be substituted by init_gcc_specs.

Alternatively, we could try disabling the init_gcc_specs rewriting for the
ia64-hpux target, and then putting the entire rule we want in the
config/ia64/hpux.h file, but I don't think that big of a patch is needed.

A better alternative would be deleting the LIBGCC_SPEC rule in
config/ia64/hpux.h, but I don't know if that will work.  That might result in
the libgcc_s_hpux64 file not being used anymore.  I also don't know whether
that matters.  I would guess that the multilibbing support should find and use
it automatically, so in theory it shouldn't be needed, but I am unable to
check.

gcc-4.0 and later do not have a problem, because they don't define LIBGCC_SPEC
in the config/ia64/hpux.h file.

I can't test the suggested patches, as I don't have an ia64-hpux machine.


-- 

wilson at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |wilson at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-11-09 01:45:26
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24718