class.c (finish_struct_1): Set things up for 0-width bitfields like we do for others.

	* class.c (finish_struct_1): Set things up for 0-width bitfields
	like we do for others.
	* decl.c (check_tag_decl): New fn.
	(shadow_tag): Split out from here.
	* decl2.c (grok_x_components): Call it.

From-SVN: r23762

gcc/cp/ChangeLog

+1998-11-23  Jason Merrill  <jason@yorick.cygnus.com>
+
+	* class.c (finish_struct_1): Set things up for 0-width bitfields
+	like we do for others.
+
+	* decl.c (check_tag_decl): New fn.
+	(shadow_tag): Split out from here.
+	* decl2.c (grok_x_components): Call it.
+
 1998-11-22  Jason Merrill  <jason@yorick.cygnus.com>
 
 	* decl.c: Lose warn_about_return_type.

gcc/cp/class.c

@@ -3669,23 +3669,24 @@ finish_struct_1 (t, warn_anon)
 				 x, TREE_TYPE (x));
 		}
 
-	      if (DECL_INITIAL (x) == NULL_TREE)
-		;
-	      else if (width == 0)
+	      if (DECL_INITIAL (x))
 		{
+		  DECL_INITIAL (x) = NULL_TREE;
+		  DECL_FIELD_SIZE (x) = width;
+		  DECL_BIT_FIELD (x) = 1;
+
+		  if (width == 0)
+		    {
 #ifdef EMPTY_FIELD_BOUNDARY
-		  DECL_ALIGN (x) = MAX (DECL_ALIGN (x), EMPTY_FIELD_BOUNDARY);
+		      DECL_ALIGN (x) = MAX (DECL_ALIGN (x),
+					    EMPTY_FIELD_BOUNDARY);
 #endif
 #ifdef PCC_BITFIELD_TYPE_MATTERS
-		  DECL_ALIGN (x) = MAX (DECL_ALIGN (x),
-					TYPE_ALIGN (TREE_TYPE (x)));
+		      if (PCC_BITFIELD_TYPE_MATTERS)
+			DECL_ALIGN (x) = MAX (DECL_ALIGN (x),
+					      TYPE_ALIGN (TREE_TYPE (x)));
 #endif
-		}
-	      else
-		{
-		  DECL_INITIAL (x) = NULL_TREE;
-		  DECL_FIELD_SIZE (x) = width;
-		  DECL_BIT_FIELD (x) = 1;
+		    }
 		}
 	    }
 	  else

gcc/cp/cp-tree.h

@@ -2706,6 +2706,7 @@ extern int init_type_desc			PROTO((void));
 extern tree define_function
 	PROTO((char *, tree, enum built_in_function,
 	       void (*) (tree), char *));
+extern tree check_tag_decl			PROTO((tree));
 extern void shadow_tag				PROTO((tree));
 extern tree groktypename			PROTO((tree));
 extern tree start_decl				PROTO((tree, tree, int, tree, tree));

gcc/cp/decl.c

@@ -6452,41 +6452,33 @@ fixup_anonymous_union (t)
     error ("an anonymous union cannot have function members");
 }
 
-/* Called when a declaration is seen that contains no names to declare.
-   If its type is a reference to a structure, union or enum inherited
-   from a containing scope, shadow that tag name for the current scope
-   with a forward reference.
-   If its type defines a new named structure or union
-   or defines an enum, it is valid but we need not do anything here.
-   Otherwise, it is an error.
+/* Make sure that a declaration with no declarator is well-formed, i.e.
+   just defines a tagged type or anonymous union.
 
-   C++: may have to grok the declspecs to learn about static,
-   complain for anonymous unions.  */
+   Returns the type defined, if any.  */
 
-void
-shadow_tag (declspecs)
+tree
+check_tag_decl (declspecs)
      tree declspecs;
 {
-  int found_tag = 0;
+  int found_type = 0;
   tree ob_modifier = NULL_TREE;
   register tree link;
-  register enum tree_code code, ok_code = ERROR_MARK;
   register tree t = NULL_TREE;
 
   for (link = declspecs; link; link = TREE_CHAIN (link))
     {
       register tree value = TREE_VALUE (link);
 
-      code = TREE_CODE (value);
-      if (IS_AGGR_TYPE_CODE (code) || code == ENUMERAL_TYPE)
+      if (TYPE_P (value))
 	{
-	  my_friendly_assert (TYPE_MAIN_DECL (value) != NULL_TREE, 261);
-
-	  maybe_process_partial_specialization (value);
+	  ++found_type;
 
-	  t = value;
-	  ok_code = code;
-	  found_tag++;
+	  if (IS_AGGR_TYPE (value) || TREE_CODE (value) == ENUMERAL_TYPE)
+	    {
+	      my_friendly_assert (TYPE_MAIN_DECL (value) != NULL_TREE, 261);
+	      t = value;
+	    }
 	}
       else if (value == ridpointers[(int) RID_STATIC]
 	       || value == ridpointers[(int) RID_EXTERN]
@@ -6494,31 +6486,22 @@ shadow_tag (declspecs)
 	       || value == ridpointers[(int) RID_REGISTER]
 	       || value == ridpointers[(int) RID_INLINE]
 	       || value == ridpointers[(int) RID_VIRTUAL]
+	       || (value == ridpointers[(int) RID_FRIEND]
+		   && (current_class_type == NULL_TREE
+		       || current_scope () != current_class_type))
+	       || value == ridpointers[(int) RID_CONST]
+	       || value == ridpointers[(int) RID_VOLATILE]
 	       || value == ridpointers[(int) RID_EXPLICIT])
 	ob_modifier = value;
     }
 
-  /* This is where the variables in an anonymous union are
-     declared.  An anonymous union declaration looks like:
-     union { ... } ;
-     because there is no declarator after the union, the parser
-     sends that declaration here.  */
-  if (ok_code == UNION_TYPE
-      && t != NULL_TREE
-      && ((TREE_CODE (TYPE_NAME (t)) == IDENTIFIER_NODE
-	   && ANON_AGGRNAME_P (TYPE_NAME (t)))
-	  || (TREE_CODE (TYPE_NAME (t)) == TYPE_DECL
-	      && ANON_AGGRNAME_P (TYPE_IDENTIFIER (t)))))
-    {
-      fixup_anonymous_union (t);
-
-      if (TYPE_FIELDS (t))
-	{
-	  tree decl = grokdeclarator (NULL_TREE, declspecs, NORMAL, 0,
-				      NULL_TREE);
-	  finish_anon_union (decl);
-	}
-    }
+  if (found_type > 1)
+    error ("multiple types in one declaration");
+    
+  if (t == NULL_TREE)
+    pedwarn ("declaration does not declare anything");
+  else if (ANON_UNION_TYPE_P (t))
+    return t;
   else
     {
       /* Anonymous unions are objects, that's why we only check for
@@ -6529,6 +6512,8 @@ shadow_tag (declspecs)
 	  if (ob_modifier == ridpointers[(int) RID_INLINE]
 	      || ob_modifier == ridpointers[(int) RID_VIRTUAL])
 	    cp_error ("`%D' can only be specified for functions", ob_modifier);
+	  else if (ob_modifier == ridpointers[(int) RID_FRIEND])
+	    cp_error ("`%D' can only be specified inside a class", ob_modifier);
 	  else if (ob_modifier == ridpointers[(int) RID_EXPLICIT])
 	    cp_error ("`%D' can only be specified for constructors",
 		      ob_modifier);
@@ -6536,11 +6521,46 @@ shadow_tag (declspecs)
 	    cp_error ("`%D' can only be specified for objects and functions",
 		      ob_modifier);
 	}
+    }
 
-      if (found_tag == 0)
-	cp_error ("abstract declarator used as declaration");
-      else if (found_tag > 1)
-	pedwarn ("multiple types in one declaration");
+  return t;
+}
+
+/* Called when a declaration is seen that contains no names to declare.
+   If its type is a reference to a structure, union or enum inherited
+   from a containing scope, shadow that tag name for the current scope
+   with a forward reference.
+   If its type defines a new named structure or union
+   or defines an enum, it is valid but we need not do anything here.
+   Otherwise, it is an error.
+
+   C++: may have to grok the declspecs to learn about static,
+   complain for anonymous unions.  */
+
+void
+shadow_tag (declspecs)
+     tree declspecs;
+{
+  tree t = check_tag_decl (declspecs);
+
+  if (t)
+    maybe_process_partial_specialization (t);
+
+  /* This is where the variables in an anonymous union are
+     declared.  An anonymous union declaration looks like:
+     union { ... } ;
+     because there is no declarator after the union, the parser
+     sends that declaration here.  */
+  if (t && ANON_UNION_TYPE_P (t))
+    {
+      fixup_anonymous_union (t);
+
+      if (TYPE_FIELDS (t))
+	{
+	  tree decl = grokdeclarator (NULL_TREE, declspecs, NORMAL, 0,
+				      NULL_TREE);
+	  finish_anon_union (decl);
+	}
     }
 }
 
@@ -10761,9 +10781,9 @@ grokdeclarator (declarator, declspecs, decl_context, initialized, attrlist)
 							   type))
 		  /* If we just return the declaration, crashes
 		     will sometimes occur.  We therefore return
-			 void_type_node, as if this was a friend
-			 declaration, to cause callers to completely
-			 ignore this declaration.  */
+		     void_type_node, as if this was a friend
+		     declaration, to cause callers to completely
+		     ignore this declaration.  */
 		  return void_type_node;
 	      }
 

gcc/cp/decl2.c

@@ -858,17 +858,14 @@ grok_x_components (specs)
   struct pending_inline **p;
   tree t;
 
-  t = groktypename (build_decl_list (strip_attrs (specs), NULL_TREE)); 
-  
-  if (t == NULL_TREE)
-    {
-      cp_error ("invalid member declaration");
-      return;
-    }
+  specs = strip_attrs (specs);
+
+  check_tag_decl (specs);
+  t = groktypename (build_decl_list (specs, NULL_TREE)); 
 
   /* The only case where we need to do anything additional here is an
      anonymous union field, e.g.: `struct S { union { int i; }; };'.  */
-  if (!ANON_UNION_TYPE_P (t))
+  if (t == NULL_TREE || !ANON_UNION_TYPE_P (t))
     return;
 
   fixup_anonymous_union (t);