[C++ PATCH] 'std' identifier not needed

https://gcc.gnu.org/ml/gcc-patches/2019-10/msg01707.html
	* cp-tree.c (CPTI_STD_IDENTIFIER): Delete.
	(std_identifier): Delete.
	(DECL_NAME_SPACE_STD_P): Compare against std_node.
	* decl.c (initialize_predefined_identifiers): 'std' is not needed.
	(cxx_init_decl_processing): Adjust creation of ::std.  Use
	{push,pop}_nested_namespace.
	(cxx_builtin_function): Use {push,pop}_nested_namespace.
	* except.c (init_exception_processing): Likewise.
	* rtti.c (init_rtti_processing): Likewise.

From-SVN: r277365

gcc/cp/ChangeLog

+2019-10-23  Nathan Sidwell  <nathan@acm.org>
+
+	* cp-tree.c (CPTI_STD_IDENTIFIER): Delete.
+	(std_identifier): Delete.
+	(DECL_NAME_SPACE_STD_P): Compare against std_node.
+	* decl.c (initialize_predefined_identifiers): 'std' is not needed.
+	(cxx_init_decl_processing): Adjust creation of ::std.  Use
+	{push,pop}_nested_namespace.
+	(cxx_builtin_function): Use {push,pop}_nested_namespace.
+	* except.c (init_exception_processing): Likewise.
+	* rtti.c (init_rtti_processing): Likewise.
+
 2019-10-23  Jason Merrill  <jason@redhat.com>
 
 	Implement P1286R2, Contra CWG1778

gcc/cp/cp-tree.h

@@ -149,7 +149,6 @@ enum cp_tree_index
     CPTI_PFN_IDENTIFIER,
     CPTI_VPTR_IDENTIFIER,
     CPTI_GLOBAL_IDENTIFIER,
-    CPTI_STD_IDENTIFIER,
     CPTI_ANON_IDENTIFIER,
     CPTI_AUTO_IDENTIFIER,
     CPTI_DECLTYPE_AUTO_IDENTIFIER,
@@ -289,7 +288,6 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
 #define vptr_identifier			cp_global_trees[CPTI_VPTR_IDENTIFIER]
 /* The name of the ::, std & anon namespaces.  */
 #define global_identifier		cp_global_trees[CPTI_GLOBAL_IDENTIFIER]
-#define std_identifier			cp_global_trees[CPTI_STD_IDENTIFIER]
 #define anon_identifier			cp_global_trees[CPTI_ANON_IDENTIFIER]
 /* auto and declspec(auto) identifiers.  */
 #define auto_identifier			cp_global_trees[CPTI_AUTO_IDENTIFIER]
@@ -3335,9 +3333,7 @@ struct GTY(()) lang_decl {
 
 /* Nonzero if NODE is the std namespace.  */
 #define DECL_NAMESPACE_STD_P(NODE)			\
-  (TREE_CODE (NODE) == NAMESPACE_DECL			\
-   && CP_DECL_CONTEXT (NODE) == global_namespace	\
-   && DECL_NAME (NODE) == std_identifier)
+  ((NODE) == std_node)
 
 /* In a TREE_LIST in an attribute list, indicates that the attribute
    must be applied at instantiation time.  */

gcc/cp/decl.c

@@ -4178,7 +4178,6 @@ initialize_predefined_identifiers (void)
     {"_vptr", &vptr_identifier, cik_normal},
     {"__vtt_parm", &vtt_parm_identifier, cik_normal},
     {"::", &global_identifier, cik_normal},
-    {"std", &std_identifier, cik_normal},
       /* The demangler expects anonymous namespaces to be called
 	 something starting with '_GLOBAL__N_'.  It no longer needs
 	 to be unique to the TU.  */
@@ -4262,7 +4261,7 @@ cxx_init_decl_processing (void)
   current_lang_name = lang_name_c;
 
   /* Create the `std' namespace.  */
-  push_namespace (std_identifier);
+  push_namespace (get_identifier ("std"));
   std_node = current_namespace;
   pop_namespace ();
 
@@ -4392,14 +4391,14 @@ cxx_init_decl_processing (void)
 	tree bad_alloc_type_node;
 	tree bad_alloc_decl;
 
-	push_namespace (std_identifier);
+	push_nested_namespace (std_node);
 	bad_alloc_id = get_identifier ("bad_alloc");
 	bad_alloc_type_node = make_class_type (RECORD_TYPE);
 	TYPE_CONTEXT (bad_alloc_type_node) = current_namespace;
 	bad_alloc_decl
 	  = create_implicit_typedef (bad_alloc_id, bad_alloc_type_node);
 	DECL_CONTEXT (bad_alloc_decl) = current_namespace;
-	pop_namespace ();
+	pop_nested_namespace (std_node);
 
 	new_eh_spec
 	  = add_exception_specifier (NULL_TREE, bad_alloc_type_node, -1);
@@ -4451,11 +4450,11 @@ cxx_init_decl_processing (void)
 
     if (aligned_new_threshold)
       {
-	push_namespace (std_identifier);
+	push_nested_namespace (std_node);
 	tree align_id = get_identifier ("align_val_t");
 	align_type_node = start_enum (align_id, NULL_TREE, size_type_node,
 				      NULL_TREE, /*scoped*/true, NULL);
-	pop_namespace ();
+	pop_nested_namespace (std_node);
 
 	/* operator new (size_t, align_val_t); */
 	newtype = build_function_type_list (ptr_type_node, size_type_node,
@@ -4663,10 +4662,10 @@ cxx_builtin_function (tree decl)
     {
       tree std_decl = copy_decl (decl);
 
-      push_namespace (std_identifier);
+      push_nested_namespace (std_node);
       DECL_CONTEXT (std_decl) = FROB_CONTEXT (std_node);
       pushdecl (std_decl);
-      pop_namespace ();
+      pop_nested_namespace (std_node);
     }
 
   DECL_CONTEXT (decl) = FROB_CONTEXT (current_namespace);

gcc/cp/except.c

@@ -51,14 +51,14 @@ init_exception_processing (void)
   tree tmp;
 
   /* void std::terminate (); */
-  push_namespace (std_identifier);
+  push_nested_namespace (std_node);
   tmp = build_function_type_list (void_type_node, NULL_TREE);
   terminate_fn = build_cp_library_fn_ptr ("terminate", tmp,
 					   ECF_NOTHROW | ECF_NORETURN
 					   | ECF_COLD);
   gcc_checking_assert (TREE_THIS_VOLATILE (terminate_fn)
 		       && TREE_NOTHROW (terminate_fn));
-  pop_namespace ();
+  pop_nested_namespace (std_node);
 
   /* void __cxa_call_unexpected(void *); */
   tmp = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);

gcc/cp/rtti.c

@@ -168,10 +168,10 @@ init_rtti_processing (void)
 {
   tree type_info_type;
 
-  push_namespace (std_identifier);
+  push_nested_namespace (std_node);
   type_info_type = xref_tag (class_type, get_identifier ("type_info"),
 			     /*tag_scope=*/ts_current, false);
-  pop_namespace ();
+  pop_nested_namespace (std_node);
   const_type_info_type_node
     = cp_build_qualified_type (type_info_type, TYPE_QUAL_CONST);
   type_info_ptr_type = build_pointer_type (const_type_info_type_node);