Re: [PATCH 1/1] gold: Avoid duplicate PLT stub symbols on PowerPC

[Alan Modra <amodra at gmail dot com>]

On Sun, Jun 18, 2017 at 10:58:03PM +0100, James Clarke wrote:
> If two objects are compiled with -fPIC or -fPIE and call the same
> function, two different PLT entries are created, one for each object,

I'd be surprised if that was so when using your simple testcase, and
testing here verifies it.  There is a situation where this can occur:
In a very large binary it may be necessary to create multiple stubs to
call a given function, because calls are so far apart that a single
stub cannot be reached by a "bl" instruction.  However, that case
ought to be covered by this->uniq_ being different for each
stub_table.  So I'm not sure how you are getting the failure.

> but the same stub symbol name is used for both. Therefore let's make
> the names unique by incorporating the object's uniq_ value where
> necessary.
> 
> gold/
> 	* (Stub_table::define_stub_syms): Include object's uniq_ value
> 	when set for non-local symbols as well.

This won't work.  object_ isn't set for ppc64 globals.  See the
Plt_stub_ent constructors.

-- 
Alan Modra
Australia Development Lab, IBM