[Bug lto/47247] Linker plugin specification makes it difficult to handle COMDATs

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47247

--- Comment #11 from H.J. Lu <hjl.tools at gmail dot com> 2011-01-10 21:01:55 UTC ---
(In reply to comment #10)
> > What undesirable things may happen if we mark a COMDAT symbol
> > PREVAILING_DEF? Is that we won't know which one will be used
> > if both LTO and non-LTO objects define the same COMAT symbol?
> 
> excatly, we don't know if something else in the same DSO is defining this
> COMDAT.
> Also the plugin specs explicitely say that plugin is required to provide this
> symbol in the output per the paragraph I quoted.
> 
> Cary: the update seems fine to me. Any chance to get it implemented on plugin
> side? Adding support in GCC is easy (and we can even keep the current trick of
> not outputing some COMDATs in place until old linkers gets out of busyness)

Adding to hjl/lto-mixed branch should be easy. If you can send
me a GCC patch, I will update hjl/lto-mixed branch.