[C++ PATCH] Fix -frepo (PR c++/36364)

[Mark Mitchell]

Jakub Jelinek wrote:

>   std::basic_string <char, std::char_traits <char>, __gnu_cxx::__mt_alloc <char> > s;

> doesn't link with -frepo.  The problem is a static const data member with
> initializer, which repo_emit_p returns 2 for (to make sure it is properly
> optimized out when possible), but then import_export_decl sees the
> -frepo implied -fno-implicit-templates and doesn't emit it at all.

If I understand correctly, the problem is that we have a static data 
member of a template which is marked as required by collect2, but then 
when we recompile the file, is not actually emitted.  Is that right?

If so, I think the fix is to honor IDENTIFIER_REPO_CHOSEN for the 
VAR_DECL case of a static data member initialized by an integral 
constant expression.  Change the code in this test:

       if (DECL_INTEGRAL_CONSTANT_VAR_P (decl)
           && DECL_CLASS_SCOPE_P (decl))

to (1) add the variable to pending_repo, and (2) if 
IDENTIFIER_REPO_CHOSEN return 1, otherwise return 2.  Probably the:

   if (!DECL_REPO_AVAILABLE...)

block should be factored into a helper function.

Does that work?

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713