[Bug c++/32470] fvisibility=hidden without effect in some casses

["gd at spherenet dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from gd at spherenet dot de  2007-06-25 23:38 -------
Here is the reduced testcase which shows the bug:
=============
namespace std __attribute__((__visibility__("default"))) {
  template<typename _CharT>
  class basic_streambuf
  {
    friend void getline();
  };
  extern template class basic_streambuf<char>;
}

class Test
{
  void test();
};
void Test::test() { }
==============
The extern declaration triggers instantiate_class_template (pt.c) before the
scope of the namespace is left and its visibility popped. While handling the
friend declaration, we push into the namespace's scope a second time which
clears its has_visibility flag. Hence, the visibility is not popped when we
finally leave the namespace.

What about the following patch proposal:
        * cp/name-lookup.c (push_namespace_with_attribs) Do not clear the
        has_visibility flag when entering a namespace's scope, ...
        (leave_scope) ... but when leaving

--- gcc-4_2-branch/gcc/cp/name-lookup.c (revision 126002)
+++ gcc-4_2-branch/gcc/cp/name-lookup.c (working copy)
@@ -1350,7 +1350,12 @@

 #ifdef HANDLE_PRAGMA_VISIBILITY
   if (scope->has_visibility)
-    pop_visibility ();
+    {
+      pop_visibility ();
+      /* Clear has_visibility in case the next namespace-definition has
+         no visibility attribute. */
+      scope->has_visibility = 0;
+    }
 #endif

   /* Move one nesting level up.  */
@@ -3067,9 +3072,6 @@
   current_namespace = d;

 #ifdef HANDLE_PRAGMA_VISIBILITY
-  /* Clear has_visibility in case a previous namespace-definition had a
-     visibility attribute and this one doesn't.  */
-  current_binding_level->has_visibility = 0;
   for (d = attributes; d; d = TREE_CHAIN (d))
     {
       tree name = TREE_PURPOSE (d);


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32470