[Bug lto/81004] [7/8 Regression] linking failed with -flto and static libboost_program_options

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81004

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #18 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Let me try to understand the problem.  In .res file we have:
328 e6522ac3d089e792 PREVAILING_DEF
_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED1Ev
333 e6522ac3d089e792 PREVAILING_DEF_IRONLY
_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev

We end up privatizing _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED2Ev
and keep _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED1Ev external.
This seems correct but for some reason we do not emit .globl at the time we
produce the alias. This is because TREE_PUBLIC of alias->decl is not set.
Wonder why that happens.

do_assemble_alias contains:
  /* Make name accessible from other files, if appropriate.  */                 

  if (TREE_PUBLIC (decl) || TREE_PUBLIC (orig_decl))                            
    {                                                                           
      globalize_decl (decl);                                                    
      maybe_assemble_visibility (decl);                                         
    }                                                                           

which looks like it is impossible to produce non-public alias of public symbol
that looks quite wrong (we do make use of local aliases to public symbols and
we do not want those exported). Perhaps we never realy set TREE_PUBLIC of those
aliases as expected?