Re: [RFA] Check solib bfd arch

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Joel Brobecker wrote:

> I now see:
> 
>     (gdb) run
>     Starting program: /[...]/sparc64/ex/task_switch 
>     warning: `/usr/platform/SUNW,Sun-Fire-V440/lib/sparcv9/libc_psr.so.1': Shared library architecture sparc:v9a is not compatible with target architecture sparc:v9.
> 
> > +  if (b->compatible (b, bfd_get_arch_info (abfd)) != b)
> 
> In my case, b->compatible is bfd_default_compatible. the architecture
> is set to sparc:v9, and the shared library's architecture is sparc:v9a.
> The problem is that b->compatible is returning the architecture that
> is "more featureful" of the two, which in this case is sparc:v9a.
> As a result, we emit the warning.
> 
> Looks to me like the check is too aggressive and should be changed
> to == 0. Would that be correct?

Well, the check is modeled after the one in osabi.c:can_run_code_for
which carries the comment:

  /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
     incompatible.  But if they are compatible, it returns the 'more
     featureful' of the two arches.  That is, if A can run code
     written for B, but B can't run code written for A, then it'll
     return A.

In your particular case, the result of compatible appears to indicate
that the target architecture sparc:v9 *cannot* run code written for
the architecture sparc:v9a; if this were true (I'm not sure about 
such sparc architecture details), then it would be correct to reject
those shared libraries ...

In any case, I do not think the checks in osabi.c (for the main
executable) and in solib.c (for shared libraries) should be different.

Hui Zhu wrote:

> Could you please try it with "bfd_arch_rs6000 and bfd_arch_powerpc"?
> Or Ulrich, maybe you can help us with it.  :)

Unfortunately, I don't have access to an old-style RS/6000 machine
myself ...

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com