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, 40 insertions, 59 deletions

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 0fe74b2..2f1a2f0 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -1340,18 +1340,17 @@ check_redeclaration_no_default_args (tree decl)
    the function or function template in the translation unit."  */
 
 static void
-check_no_redeclaration_friend_default_args (tree olddecl, tree newdecl,
-					    bool olddecl_hidden_p)
+check_no_redeclaration_friend_default_args (tree olddecl, tree newdecl)
 {
-  if (!olddecl_hidden_p && !DECL_FRIEND_P (newdecl))
+  if (!DECL_UNIQUE_FRIEND_P (olddecl) && !DECL_UNIQUE_FRIEND_P (newdecl))
     return;
 
   for (tree t1 = FUNCTION_FIRST_USER_PARMTYPE (olddecl),
 	 t2 = FUNCTION_FIRST_USER_PARMTYPE (newdecl);
        t1 && t1 != void_list_node;
        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
-    if ((olddecl_hidden_p && TREE_PURPOSE (t1))
-	|| (DECL_FRIEND_P (newdecl) && TREE_PURPOSE (t2)))
+    if ((DECL_UNIQUE_FRIEND_P (olddecl) && TREE_PURPOSE (t1))
+	|| (DECL_UNIQUE_FRIEND_P (newdecl) && TREE_PURPOSE (t2)))
       {
 	auto_diagnostic_group d;
 	if (permerror (DECL_SOURCE_LOCATION (newdecl),
@@ -1444,8 +1443,7 @@ tree
 duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
 {
   unsigned olddecl_uid = DECL_UID (olddecl);
-  int olddecl_friend = 0, types_match = 0;
-  int olddecl_hidden_friend = 0;
+  int types_match = 0;
   int new_defines_function = 0;
   tree new_template_info;
   location_t olddecl_loc = DECL_SOURCE_LOCATION (olddecl);
@@ -1987,8 +1985,7 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
 		 argument expression, that declaration... shall be the only
 		 declaration of the function or function template in the
 		 translation unit."  */
-	      check_no_redeclaration_friend_default_args
-		(olddecl, newdecl, was_hidden);
+	      check_no_redeclaration_friend_default_args (olddecl, newdecl);
 	    }
 	}
     }
@@ -2135,12 +2132,6 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
   else
     DECL_ATTRIBUTES (olddecl) = DECL_ATTRIBUTES (newdecl);
 
-  if (DECL_DECLARES_FUNCTION_P (olddecl))
-    {
-      olddecl_friend = DECL_FRIEND_P (STRIP_TEMPLATE (olddecl));
-      olddecl_hidden_friend = olddecl_friend && was_hidden;
-    }
-
   if (TREE_CODE (newdecl) == TEMPLATE_DECL)
     {
       tree old_result = DECL_TEMPLATE_RESULT (olddecl);
@@ -2167,8 +2158,10 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
 		 declaration of the function or function template in the
 		 translation unit."  */
 	      check_no_redeclaration_friend_default_args
-		(old_result, new_result, olddecl_hidden_friend);
+		(old_result, new_result);
 	    }
+	  if (!DECL_UNIQUE_FRIEND_P (old_result))
+	    DECL_UNIQUE_FRIEND_P (new_result) = false;
 
 	  check_default_args (newdecl);
 
@@ -2366,6 +2359,9 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
 	      && !DECL_FUNCTION_SPECIFIC_OPTIMIZATION (newdecl))
 	    DECL_FUNCTION_SPECIFIC_OPTIMIZATION (newdecl)
 	      = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (olddecl);
+
+	  if (!DECL_UNIQUE_FRIEND_P (olddecl))
+	    DECL_UNIQUE_FRIEND_P (newdecl) = false;
 	}
       else
 	{
@@ -2885,8 +2881,6 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
     }
 
   DECL_UID (olddecl) = olddecl_uid;
-  if (olddecl_friend)
-    DECL_FRIEND_P (olddecl) = true;
 
   /* NEWDECL contains the merged attribute lists.
      Update OLDDECL to be the same.  */
@@ -3062,7 +3056,7 @@ redeclaration_error_message (tree newdecl, tree olddecl)
            definition and shall be the only declaration of the
            function template in the translation unit.  */
       if ((cxx_dialect != cxx98)
-          && TREE_CODE (ot) == FUNCTION_DECL && DECL_FRIEND_P (ot)
+          && TREE_CODE (ot) == FUNCTION_DECL && DECL_UNIQUE_FRIEND_P (ot)
 	  && !check_default_tmpl_args (nt, DECL_TEMPLATE_PARMS (newdecl),
                                        /*is_primary=*/true,
 				       /*is_partial=*/false,
@@ -3073,7 +3067,8 @@ redeclaration_error_message (tree newdecl, tree olddecl)
       return NULL;
     }
   else if (VAR_P (newdecl)
-	   && CP_DECL_THREAD_LOCAL_P (newdecl) != CP_DECL_THREAD_LOCAL_P (olddecl)
+	   && (CP_DECL_THREAD_LOCAL_P (newdecl)
+	       != CP_DECL_THREAD_LOCAL_P (olddecl))
 	   && (! DECL_LANG_SPECIFIC (olddecl)
 	       || ! CP_DECL_THREADPRIVATE_P (olddecl)
 	       || CP_DECL_THREAD_LOCAL_P (newdecl)))
@@ -16110,36 +16105,21 @@ bool
 start_preparsed_function (tree decl1, tree attrs, int flags)
 {
   tree ctype = NULL_TREE;
-  tree fntype;
-  tree restype;
-  int doing_friend = 0;
-  cp_binding_level *bl;
-  tree current_function_parms;
-  struct c_fileinfo *finfo
-    = get_fileinfo (LOCATION_FILE (DECL_SOURCE_LOCATION (decl1)));
-  bool honor_interface;
+  bool doing_friend = false;
 
   /* Sanity check.  */
   gcc_assert (VOID_TYPE_P (TREE_VALUE (void_list_node)));
   gcc_assert (TREE_CHAIN (void_list_node) == NULL_TREE);
 
-  fntype = TREE_TYPE (decl1);
+  tree fntype = TREE_TYPE (decl1);
   if (TREE_CODE (fntype) == METHOD_TYPE)
     ctype = TYPE_METHOD_BASETYPE (fntype);
-
-  /* ISO C++ 11.4/5.  A friend function defined in a class is in
-     the (lexical) scope of the class in which it is defined.  */
-  if (!ctype && DECL_FRIEND_P (decl1))
+  else
     {
       ctype = DECL_FRIEND_CONTEXT (decl1);
 
-      /* CTYPE could be null here if we're dealing with a template;
-	 for example, `inline friend float foo()' inside a template
-	 will have no CTYPE set.  */
-      if (ctype && TREE_CODE (ctype) != RECORD_TYPE)
-	ctype = NULL_TREE;
-      else
-	doing_friend = 1;
+      if (ctype)
+	doing_friend = true;
     }
 
   if (DECL_DECLARED_INLINE_P (decl1)
@@ -16206,7 +16186,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
      by push_nested_class.)  */
   if (processing_template_decl)
     {
-      tree newdecl1 = push_template_decl (decl1, DECL_FRIEND_P (decl1));
+      tree newdecl1 = push_template_decl (decl1, doing_friend);
       if (newdecl1 == error_mark_node)
 	{
 	  if (ctype || DECL_STATIC_FUNCTION_P (decl1))
@@ -16222,7 +16202,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
   check_function_type (decl1, DECL_ARGUMENTS (decl1));
 
   /* Build the return declaration for the function.  */
-  restype = TREE_TYPE (fntype);
+  tree restype = TREE_TYPE (fntype);
 
   if (DECL_RESULT (decl1) == NULL_TREE)
     {
@@ -16312,7 +16292,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
 
   /* Save the parm names or decls from this function's declarator
      where store_parm_decls will find them.  */
-  current_function_parms = DECL_ARGUMENTS (decl1);
+  tree current_function_parms = DECL_ARGUMENTS (decl1);
 
   /* Let the user know we're compiling this function.  */
   announce_function (decl1);
@@ -16329,7 +16309,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
      even when processing a template; this is how we get
      CFUN set up, and our per-function variables initialized.
      FIXME factor out the non-RTL stuff.  */
-  bl = current_binding_level;
+  cp_binding_level *bl = current_binding_level;
   allocate_struct_function (decl1, processing_template_decl);
 
   /* Initialize the language data structures.  Whenever we start
@@ -16384,14 +16364,16 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
 	}
     }
 
-  honor_interface = (!DECL_TEMPLATE_INSTANTIATION (decl1)
-		     /* Implicitly-defined methods (like the
-			destructor for a class in which no destructor
-			is explicitly declared) must not be defined
-			until their definition is needed.  So, we
-			ignore interface specifications for
-			compiler-generated functions.  */
-		     && !DECL_ARTIFICIAL (decl1));
+  bool honor_interface = (!DECL_TEMPLATE_INSTANTIATION (decl1)
+			  /* Implicitly-defined methods (like the
+			     destructor for a class in which no destructor
+			     is explicitly declared) must not be defined
+			     until their definition is needed.  So, we
+			     ignore interface specifications for
+			     compiler-generated functions.  */
+			  && !DECL_ARTIFICIAL (decl1));
+  struct c_fileinfo *finfo
+    = get_fileinfo (LOCATION_FILE (DECL_SOURCE_LOCATION (decl1)));
 
   if (processing_template_decl)
     /* Don't mess with interface flags.  */;
@@ -17311,18 +17293,17 @@ grokmethod (cp_decl_specifier_seq *declspecs,
   /* We process method specializations in finish_struct_1.  */
   if (processing_template_decl && !DECL_TEMPLATE_SPECIALIZATION (fndecl))
     {
-      fndecl = push_template_decl (fndecl, DECL_FRIEND_P (fndecl));
+      /* Avoid calling decl_spec_seq... until we have to.  */
+      bool friendp = decl_spec_seq_has_spec_p (declspecs, ds_friend);
+      fndecl = push_template_decl (fndecl, friendp);
       if (fndecl == error_mark_node)
 	return fndecl;
     }
 
-  if (! DECL_FRIEND_P (fndecl))
+  if (DECL_CHAIN (fndecl) && !decl_spec_seq_has_spec_p (declspecs, ds_friend))
     {
-      if (DECL_CHAIN (fndecl))
-	{
-	  fndecl = copy_node (fndecl);
-	  TREE_CHAIN (fndecl) = NULL_TREE;
-	}
+      fndecl = copy_node (fndecl);
+      TREE_CHAIN (fndecl) = NULL_TREE;
     }
 
   cp_finish_decl (fndecl, NULL_TREE, false, NULL_TREE, 0);