Re: g++.bob/static1.C

[Zack Weinberg <zack at codesourcery dot com>]

On Tue, Oct 23, 2001 at 08:13:41AM -0700, Mark Mitchell wrote:
> 
> >This was introduced by the patch in
> >http://gcc.gnu.org/ml/gcc-patches/1999-09n/msg00782.html which is
> >trying to enforce a distinction between poplevel and poplevel_class.
> >(I do not see why this is desirable.)
> 
> This was done to avoid a semi-common bug in the C++ front end: popping
> a class binding level when you meant to be popping an ordinary binding
> level.  It sounds like one solution is to create a new callback, called
> pop_all_binding_levels, which defaults to calling poplevel(0, 0, 0)
> repeatedly, but in the C++ front-end is pop_everything.

This patch does just that.  I considered cleaning up a bit - both C
and C++ currently pop all binding levels in several other places on
the way out of the parser - but decided just to fix the current
problem.

Bootstrapped i686-linux; the difference in testsuite results is 

-FAIL: g++.dg/parse/saved1.C (test for excess errors)
-FAIL: g++.bob/static1.C (test for excess errors)
+FAIL: g77.f-torture/compile/20010519-1.f,  -O1  

The new Fortran failure is an ICE in alloc_aux_for_edge (cfg.c:649)
and I do not believe it is a consequence of this patch.  I've updated
again and will run another build to see if it's a transient glitch.

Why is struct lang_hooks in toplev.h instead of langhooks.h?

zw

	* langhooks.c (lang_hook_default_clear_binding_stack): New.
	(lang_hook_default_get_alias_set): Move next to other alias
	hooks.
	* langhooks.h: Prototype lang_hook_default_clear_binding_stack.
	(LANG_HOOKS_CLEAR_BINDING_STACK): New macro.
	(LANG_HOOKS_INITIALIZER): Add it.
	* toplev.h (struct lang_hooks): Add clear_binding_stack.
	* toplev.c (compile_file):  Call lang_hooks.clear_binding_stack
	instead of a loop calling poplevel.

cp:
	* cp-lang.c: Redefine LANG_HOOKS_CLEAR_BINDING_STACK to
	pop_everything.

===================================================================
Index: langhooks.c
--- langhooks.c	2001/10/23 18:51:08	1.5
+++ langhooks.c	2001/10/24 08:16:50
@@ -36,16 +36,6 @@ lang_hook_default_do_nothing ()
 {
 }
 
-/* Provide a default routine for alias sets that always returns -1.  This
-   is used by languages that don't need to do anything special.  */
-
-HOST_WIDE_INT
-lang_hook_default_get_alias_set (t)
-     tree t ATTRIBUTE_UNUSED;
-{
-  return -1;
-}
-
 /* Do nothing; the default hook to decode an option.  */
 
 int
@@ -54,6 +44,25 @@ lang_hook_default_decode_option (argc, a
      char **argv ATTRIBUTE_UNUSED;
 {
   return 0;
+}
+
+/* Provide a default routine to clear the binding stack.  This is used
+   by languages that don't need to do anything special.  */
+void
+lang_hook_default_clear_binding_stack ()
+{
+  while (! global_bindings_p ())
+    poplevel (0, 0, 0);
+}
+
+/* Provide a default routine for alias sets that always returns -1.  This
+   is used by languages that don't need to do anything special.  */
+
+HOST_WIDE_INT
+lang_hook_default_get_alias_set (t)
+     tree t ATTRIBUTE_UNUSED;
+{
+  return -1;
 }
 
 /* Provide a hook routine for alias sets that always returns 0.  This is
===================================================================
Index: langhooks.h
--- langhooks.h	2001/10/23 18:51:08	1.4
+++ langhooks.h	2001/10/24 08:16:50
@@ -38,9 +38,11 @@ extern HOST_WIDE_INT hook_get_alias_set_
 extern void lang_hook_default_do_nothing PARAMS ((void));
 extern int lang_hook_default_decode_option PARAMS ((int, char **));
 extern HOST_WIDE_INT lang_hook_default_get_alias_set PARAMS ((tree));
+extern void lang_hook_default_clear_binding_stack PARAMS ((void));
 
 #define LANG_HOOKS_INIT			lang_hook_default_do_nothing
 #define LANG_HOOKS_FINISH		lang_hook_default_do_nothing
+#define LANG_HOOKS_CLEAR_BINDING_STACK	lang_hook_default_clear_binding_stack
 #define LANG_HOOKS_INIT_OPTIONS		lang_hook_default_do_nothing
 #define LANG_HOOKS_DECODE_OPTION	lang_hook_default_decode_option
 #define LANG_HOOKS_POST_OPTIONS		lang_hook_default_do_nothing
@@ -99,6 +101,7 @@ int tree_inlining_default_hook_anon_aggr
 #define LANG_HOOKS_INITIALIZER { \
   LANG_HOOKS_INIT, \
   LANG_HOOKS_FINISH, \
+  LANG_HOOKS_CLEAR_BINDING_STACK, \
   LANG_HOOKS_INIT_OPTIONS, \
   LANG_HOOKS_DECODE_OPTION, \
   LANG_HOOKS_POST_OPTIONS, \
===================================================================
Index: toplev.c
--- toplev.c	2001/10/23 13:34:23	1.525
+++ toplev.c	2001/10/24 08:16:51
@@ -2334,8 +2334,7 @@ compile_file (name)
 
   /* In case there were missing block closers,
      get us back to the global binding level.  */
-  while (! global_bindings_p ())
-    poplevel (0, 0, 0);
+  (*lang_hooks.clear_binding_stack) ();
 
   /* Compilation is now finished except for writing
      what's left of the symbol table output.  */
===================================================================
Index: toplev.h
--- toplev.h	2001/10/23 18:51:13	1.78
+++ toplev.h	2001/10/24 08:16:51
@@ -149,6 +149,9 @@ struct lang_hooks
   /* Called last, as a finalizer.  */
   void (*finish) PARAMS ((void));
 
+  /* Called immediately after parsing to clear the binding stack.  */
+  void (*clear_binding_stack) PARAMS ((void));
+
   /* Called to initialize options, before any calls to decode_option.  */
   void (*init_options) PARAMS ((void));
 
===================================================================
Index: cp/cp-lang.c
--- cp/cp-lang.c	2001/10/23 18:50:16	1.2
+++ cp/cp-lang.c	2001/10/24 08:16:52
@@ -32,6 +32,8 @@ static HOST_WIDE_INT cxx_get_alias_set P
 #define LANG_HOOKS_INIT cxx_init
 #undef LANG_HOOKS_FINISH
 #define LANG_HOOKS_FINISH cxx_finish
+#undef LANG_HOOKS_CLEAR_BINDING_STACK
+#define LANG_HOOKS_CLEAR_BINDING_STACK pop_everything
 #undef LANG_HOOKS_INIT_OPTIONS
 #define LANG_HOOKS_INIT_OPTIONS cxx_init_options
 #undef LANG_HOOKS_DECODE_OPTION