re PR c++/31187 (extern declaration of variable in anonymous namespace prevents…

re PR c++/31187 (extern declaration of variable in anonymous namespace prevents use of its address as template argument)

        PR c++/31187                                                               
        * typeck.c (cp_type_readonly): New fn.                                         
        * cp-tree.h: Declare it.                                                       
        * decl.c (start_decl): Set implicit DECL_THIS_STATIC here.                     
        (cp_finish_decl): Not here.                                                    
                                                                                       
        * g++.dg/ext/visibility/anon3.C: New test.

From-SVN: r123432

gcc/cp/ChangeLog

+2007-03-30  Jason Merrill  <jason@redhat.com>
+
+	PR c++/31187
+	* typeck.c (cp_type_readonly): New fn.
+	* cp-tree.h: Declare it.
+	* decl.c (start_decl): Set implicit DECL_THIS_STATIC here.
+	(cp_finish_decl): Not here.
+
 2007-03-31  Richard Guenther  <rguenther@suse.de>
 
 	* optimize.c (maybe_clone_body): Replace splay-tree usage by

gcc/cp/cp-tree.h

@@ -4742,6 +4742,7 @@ extern bool comp_ptr_ttypes_const		(tree, tree);
 extern int ptr_reasonably_similar		(tree, tree);
 extern tree build_ptrmemfunc			(tree, tree, int, bool);
 extern int cp_type_quals			(tree);
+extern bool cp_type_readonly			(tree);
 extern bool cp_has_mutable_p			(tree);
 extern bool at_least_as_qualified_p		(tree, tree);
 extern void cp_apply_type_quals_to_decl		(int, tree);

gcc/cp/decl.c

@@ -3797,6 +3797,7 @@ start_decl (const cp_declarator *declarator,
   tree decl;
   tree type, tem;
   tree context;
+  bool was_public;
 
   *pushed_scope_p = NULL_TREE;
 
@@ -3951,6 +3952,8 @@ start_decl (const cp_declarator *declarator,
 		 decl);
     }
 
+  was_public = TREE_PUBLIC (decl);
+
   /* Enter this declaration into the symbol table.  */
   tem = maybe_push_decl (decl);
 
@@ -3971,6 +3974,17 @@ start_decl (const cp_declarator *declarator,
       && !have_global_bss_p ())
     DECL_COMMON (tem) = 1;
 
+  if (TREE_CODE (tem) == VAR_DECL
+      && DECL_NAMESPACE_SCOPE_P (tem) && !TREE_PUBLIC (tem) && !was_public
+      && !DECL_THIS_STATIC (tem) && !DECL_ARTIFICIAL (tem))
+    {
+      /* This is a const variable with implicit 'static'.  Set
+	 DECL_THIS_STATIC so we can tell it from variables that are
+	 !TREE_PUBLIC because of the anonymous namespace.  */
+      gcc_assert (cp_type_readonly (TREE_TYPE (tem)));
+      DECL_THIS_STATIC (tem) = 1;
+    }
+
   if (!processing_template_decl && TREE_CODE (tem) == VAR_DECL)
     start_decl_1 (tem, initialized);
 
@@ -5283,14 +5297,6 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	{
 	  layout_var_decl (decl);
 	  maybe_commonize_var (decl);
-	  if (DECL_NAMESPACE_SCOPE_P (decl) && !TREE_PUBLIC (decl)
-	      && !DECL_THIS_STATIC (decl) && !DECL_ARTIFICIAL (decl))
-	    {
-	      /* This is a const variable with implicit 'static'.  Set
-		 DECL_THIS_STATIC so we can tell it from variables that are
-		 !TREE_PUBLIC because of the anonymous namespace.  */
-	      DECL_THIS_STATIC (decl) = 1;
-	    }
 	}
 
       make_rtl_for_nonlocal_decl (decl, init, asmspec);

gcc/cp/typeck.c

@@ -6897,6 +6897,16 @@ cp_type_quals (tree type)
   return TYPE_QUALS (type);
 }
 
+/* Returns nonzero if the TYPE is const from a C++ perspective: look inside
+   arrays.  */
+
+bool
+cp_type_readonly (tree type)
+{
+  type = strip_array_types (type);
+  return TYPE_READONLY (type);
+}
+
 /* Returns nonzero if the TYPE contains a mutable member.  */
 
 bool

gcc/testsuite/ChangeLog

+2007-04-02  Jason Merrill  <jason@redhat.com>
+
+	PR c++/31187
+	* g++.dg/ext/visibility/anon3.C: New test.
+
 2007-04-01  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/31052

gcc/testsuite/g++.dg/ext/visibility/anon3.C

+// PR c++/31187
+// Bug: the repeated declaration was confusing the compiler into
+// thinking that foo1 had language internal linkage.
+
+class foo { };
+
+namespace
+{
+  extern foo foo1;
+  foo foo1;
+}
+
+template< foo * >
+class bar { };
+
+bar< &foo1 > bar1;