[PATCH] Remove unnecessary IFUNC dispatch for __memset_chk.

[Alexander Monakov]

On Tue, 11 Aug 2015, H.J. Lu wrote:
> > Didn't know its explicitly forbidden to use nonstatic resolvers. Do we document that requirement somewhere?
> > If not then we should add it to documentation.
> 
> It makes no senses for IFUNC selector to return the address of
> a global function, which may be preempted at run-time.

That would be imposing a policy while providing a mechanism.

I think there are plausible scenarios where returning a global function from
an ifunc resolver would be natural.

To give a specific example, imagine an ifunc symbol
'printf_fortified_opportunistically', which resolves to 'printf_chk' if it is
available in the global namespace, or normal 'printf' otherwise.

Such a symbol could be in any DSO, not necessarily libc, and thus it has to be
able to pick up global symbol definitions.

Thanks.
Alexander