cp-tree.h (DECL_VAR_MARKED_P): Remove.

* cp-tree.h (DECL_VAR_MARKED_P): Remove.
	(DECL_ANON_UNION_VAR_P): New macro.
	* class.c (fixed_type_or_null): Tidy.  Use a hash table, rather
	than DECL_VAR_MARKED_P, to keep track of which variables we have
	seen.
	* decl.c (redeclaration_error_message): Complain about redeclaring
	anonymous union members at namespace scope.
	* decl2.c (build_anon_union_vars): Set DECL_ANON_UNION_VAR_P.
	* g++.dg/lookup/anon6.C: New test.

From-SVN: r125839

gcc/cp/ChangeLog

@@ -1,3 +1,14 @@
+2007-06-15  Mark Mitchell  <mark@codesourcery.com>
+
+	* cp-tree.h (DECL_VAR_MARKED_P): Remove.
+	(DECL_ANON_UNION_VAR_P): New macro.
+	* class.c (fixed_type_or_null): Tidy.  Use a hash table, rather
+	than DECL_VAR_MARKED_P, to keep track of which variables we have
+	seen.
+	* decl.c (redeclaration_error_message): Complain about redeclaring
+	anonymous union members at namespace scope.
+	* decl2.c (build_anon_union_vars): Set DECL_ANON_UNION_VAR_P.
+
 2007-06-08  Dirk Mueller  <dmueller@suse.de>
 
 	PR c++/31809

gcc/cp/class.c

@@ -5350,22 +5350,34 @@ fixed_type_or_null (tree instance, int* nonnull, int* cdtorp)
 	}
       else if (TREE_CODE (TREE_TYPE (instance)) == REFERENCE_TYPE)
 	{
+	  /* We only need one hash table because it is always left empty.  */
+	  static htab_t ht;
+	  if (!ht)
+	    ht = htab_create (37, 
+			      htab_hash_pointer,
+			      htab_eq_pointer,
+			      /*htab_del=*/NULL);
+
 	  /* Reference variables should be references to objects.  */
 	  if (nonnull)
 	    *nonnull = 1;
 
-	  /* DECL_VAR_MARKED_P is used to prevent recursion; a
+	  /* Enter the INSTANCE in a table to prevent recursion; a
 	     variable's initializer may refer to the variable
 	     itself.  */
 	  if (TREE_CODE (instance) == VAR_DECL
 	      && DECL_INITIAL (instance)
-	      && !DECL_VAR_MARKED_P (instance))
+	      && !htab_find (ht, instance))
 	    {
 	      tree type;
-	      DECL_VAR_MARKED_P (instance) = 1;
+	      void **slot;
+
+	      slot = htab_find_slot (ht, instance, INSERT);
+	      *slot = instance;
 	      type = fixed_type_or_null (DECL_INITIAL (instance),
 					 nonnull, cdtorp);
-	      DECL_VAR_MARKED_P (instance) = 0;
+	      htab_clear_slot (ht, slot);
+
 	      return type;
 	    }
 	}

gcc/cp/cp-tree.h

@@ -107,7 +107,7 @@ struct diagnostic_context;
       DECL_IMPLICIT_TYPEDEF_P (in a TYPE_DECL)
    3: DECL_IN_AGGR_P.
    4: DECL_C_BIT_FIELD (in a FIELD_DECL)
-      DECL_VAR_MARKED_P (in a VAR_DECL)
+      DECL_ANON_UNION_VAR_P (in a VAR_DECL)
       DECL_SELF_REFERENCE_P (in a TYPE_DECL)
       DECL_INVALID_OVERRIDER_P (in a FUNCTION_DECL)
    5: DECL_INTERFACE_KNOWN.
@@ -2111,10 +2111,10 @@ extern void decl_shadowed_for_var_insert (tree, tree);
   (DECL_LANG_SPECIFIC (VAR_TEMPL_TYPE_OR_FUNCTION_DECL_CHECK (NODE)) \
    ->decl_flags.u.template_info)
 
-/* For a VAR_DECL, indicates that the variable has been processed.
-   This flag is set and unset throughout the code; it is always
-   used for a temporary purpose.  */
-#define DECL_VAR_MARKED_P(NODE) \
+/* For a VAR_DECL, indicates that the variable is actually a
+   non-static data member of anonymous union that has been promoted to
+   variable status.  */
+#define DECL_ANON_UNION_VAR_P(NODE) \
   (DECL_LANG_FLAG_4 (VAR_DECL_CHECK (NODE)))
 
 /* Template information for a RECORD_TYPE or UNION_TYPE.  */

gcc/cp/decl.c

@@ -2161,8 +2161,24 @@ redeclaration_error_message (tree newdecl, tree olddecl)
     }
   else if (toplevel_bindings_p () || DECL_NAMESPACE_SCOPE_P (newdecl))
     {
-      /* Objects declared at top level:  */
-      /* If at least one is a reference, it's ok.  */
+      /* The objects have been declared at namespace scope.  If either
+	 is a member of an anonymous union, then this is an invalid
+	 redeclaration.  For example:
+
+	   int i;
+	   union { int i; };
+
+	   is invalid.  */
+      if (DECL_ANON_UNION_VAR_P (newdecl)
+	  || DECL_ANON_UNION_VAR_P (olddecl))
+	return "redeclaration of %q#D";
+      /* If at least one declaration is a reference, there is no
+	 conflict.  For example:
+
+	   int i = 3;
+	   extern int i;
+
+	 is valid.  */
       if (DECL_EXTERNAL (newdecl) || DECL_EXTERNAL (olddecl))
 	return NULL;
       /* Reject two definitions.  */

gcc/cp/decl2.c

@@ -1056,6 +1056,7 @@ build_anon_union_vars (tree type, tree object)
 	  tree base;
 
 	  decl = build_decl (VAR_DECL, DECL_NAME (field), TREE_TYPE (field));
+	  DECL_ANON_UNION_VAR_P (decl) = 1;
 
 	  base = get_base_address (object);
 	  TREE_PUBLIC (decl) = TREE_PUBLIC (base);

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2007-06-15  Mark Mitchell  <mark@codesourcery.com>
+
+	* g++.dg/lookup/anon6.C: New test.
+
 2007-06-17  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	* gcc.target/sparc/align.c: Use 'unsigned char' as element type.

gcc/testsuite/g++.dg/lookup/anon6.C

@@ -0,0 +1,11 @@
+extern int v1; // { dg-error "declared" }
+static union { int v1; }; // { dg-error "redeclaration" } 
+
+static union { int v2; }; // { dg-error "declared" }
+extern int v2; // { dg-error "redeclaration" } 
+
+int v3; // { dg-error "declared" }
+static union { int v3; }; // { dg-error "redeclaration" } 
+
+static union { int v4; }; // { dg-error "declared" }
+static union { int v4; }; // { dg-error "redeclaration" }