c++: DECL_FRIEND_P cleanup

DECL_FRIEND_P's meaning has changed over time.  It now (almost) means
the the friend function decl has not been met via an explicit decl.
This completes that transition, renaming it to DECL_UNIQUE_FRIEND_P,
so one doesn't think it is the sole indicator of friendliness (plenty
of friends do not have the flag set).  This allows reduction in the
complexity of managing the field -- all in duplicate_decls now.

	gcc/cp/
	* cp-tree.h (struct lang_decl_fn): Adjust context comment.
	(DECL_FRIEND_P): Replace with ...
	(DECL_UNIQUE_FRIEND_P): ... this.  Only for FUNCTION_DECLs.
	(DECL_FRIEND_CONTEXT): Adjust.
	* class.c (add_implicitly_declared_members): Detect friendly
	spaceship from context.
	* constraint.cc (remove_constraints): Use a checking assert.
	(maybe_substitute_reqs_for): Use DECL_UNIQUE_FRIEND_P.
	* decl.c (check_no_redeclaration_friend_default_args):
	DECL_UNIQUE_FRIEND_P is signficant, not hiddenness.
	(duplicate_decls): Adjust DECL_UNIQUE_FRIEND_P clearing.
	(redeclaration_error_message): Use DECL_UNIQUE_FRIEND_P.
	(start_preparsed_function): Correct in-class friend processing.
	Refactor some initializers.
	(grokmethod): Directly check friend decl-spec.
	* decl2.c (grokfield): Check DECL_UNIQUE_FRIEND_P.
	* friend.c (do_friend): Set DECL_UNIQUE_FRIEND_P first, remove
	extraneous conditions.  Don't re set it afterwards.
	* name-lookup.c (lookup_elaborated_type_1): Simplify revealing
	code.
	(do_pushtag): Likewise.
	* pt.c (optimize_specialization_lookup_p): Check
	DECL_UNIQUE_FRIEND_P.
	(push_template_decl): Likewise.  Drop unneeded friend setting.
	(type_dependent_expression_p): Check DECL_UNIQUE_FRIEND_P.
	libcc1/
	* libcp1plugin.cc (plugin_add_friend): Set DECL_UNIQUE_FRIEND_P.

1 files changed, 4 insertions, 11 deletions

diff --git a/gcc/cp/friend.c b/gcc/cp/friend.c
index 6a783a9..56fa960 100644
--- a/gcc/cp/friend.c
+++ b/gcc/cp/friend.c
@@ -481,8 +481,8 @@ do_friend (tree ctype, tree declarator, tree decl,
   gcc_assert (TREE_CODE (decl) == FUNCTION_DECL);
   gcc_assert (!ctype || MAYBE_CLASS_TYPE_P (ctype));
 
-  /* Every decl that gets here is a friend of something.  */
-  DECL_FRIEND_P (decl) = 1;
+  /* Friend functions are unique, until proved otherwise.  */
+  DECL_UNIQUE_FRIEND_P (decl) = 1;
 
   if (DECL_OVERRIDE_P (decl) || DECL_FINAL_P (decl))
     error ("friend declaration %qD may not have virt-specifiers",
@@ -581,17 +581,11 @@ do_friend (tree ctype, tree declarator, tree decl,
 	error ("member %qD declared as friend before type %qT defined",
 		  decl, ctype);
     }
-  /* A global friend.
-     @@ or possibly a friend from a base class ?!?  */
-  else if (TREE_CODE (decl) == FUNCTION_DECL)
+  else
     {
+      /* Namespace-scope friend function.  */
       int is_friend_template = PROCESSING_REAL_TEMPLATE_DECL_P ();
 
-      /* Friends must all go through the overload machinery,
-	 even though they may not technically be overloaded.
-
-	 Note that because classes all wind up being top-level
-	 in their scope, their friend wind up in top-level scope as well.  */
       if (funcdef_flag)
 	SET_DECL_FRIEND_CONTEXT (decl, current_class_type);
 
@@ -653,7 +647,6 @@ do_friend (tree ctype, tree declarator, tree decl,
       add_friend (current_class_type,
 		  is_friend_template ? DECL_TI_TEMPLATE (decl) : decl,
 		  /*complain=*/true);
-      DECL_FRIEND_P (decl) = 1;
     }
 
   return decl;