ios_base.h: Use _Atomic_word for reference counts.

	libstdc++/5432
	* include/bits/ios_base.h: Use _Atomic_word for reference counts.
	* include/bits/localefwd.h: Likewise.
	Also use for std::locale::id::_S_highwater.
	* src/ios.cc (ios_base::xalloc): Use _Atomic_word.
	* src/locale.cc: Support new usage of _Atomic_word.
	(std::locale::classic): Guard entire function against reentry.
	* src/localename.cc: Support new usage of _Atomic_word.

From-SVN: r49195

libstdc++-v3/ChangeLog

+2002-01-24  andrew@andypo.net
+	    (tweaks, test and commit by Loren J. Rittle  <ljrittle@acm.org>)
+
+	libstdc++/5432
+	* include/bits/ios_base.h: Use _Atomic_word for reference counts.
+	* include/bits/localefwd.h: Likewise.
+	Also use for std::locale::id::_S_highwater.
+	* src/ios.cc (ios_base::xalloc): Use _Atomic_word.
+	* src/locale.cc: Support new usage of _Atomic_word.
+	(std::locale::classic): Guard entire function against reentry.
+	* src/localename.cc: Support new usage of _Atomic_word.
+
 2002-01-24   Benjamin Kosnik  <bkoz@redhat.com>
 
 	* testsuite/22_locale/num_put_members_wchar_t.cc (test03): Use

libstdc++-v3/include/bits/ios_base.h

 // Iostreams base classes -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
+// Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -41,6 +42,8 @@
 
 #pragma GCC system_header
 
+#include <bits/atomicity.h>
+
 namespace std
 {
   // The following definitions of bitmask types are enums, not ints,
@@ -244,17 +247,18 @@ namespace std
       _Callback_list* 		_M_next;
       ios_base::event_callback 	_M_fn;
       int 			_M_index;
-      int 			_M_refcount;  // 0 means one reference.
+      _Atomic_word		_M_refcount;  // 0 means one reference.
     
       _Callback_list(ios_base::event_callback __fn, int __index, 
 		     _Callback_list* __cb)
       : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
       
       void 
-      _M_add_reference() { ++_M_refcount; } // XXX MT
-      
+      _M_add_reference() { __atomic_add(&_M_refcount, 1); }
+
       int 
-      _M_remove_reference() { return _M_refcount--; }  // 0 => OK to delete
+      _M_remove_reference() { return __exchange_and_add(&_M_refcount, -1); }
+      // 0 => OK to delete
     };
 
      _Callback_list*  	_M_callbacks;

libstdc++-v3/include/bits/localefwd.h

@@ -49,6 +49,8 @@
 #include <string> 		// For string
 #include <bits/functexcept.h>
 
+#include <bits/atomicity.h>
+
 namespace std
 {
   // NB: Don't instantiate required wchar_t facets if no wchar_t support.
@@ -317,7 +319,7 @@ namespace std
 
   private:
     // Data Members.
-    size_t 				_M_references;
+    _Atomic_word			_M_references;
     __vec_facet* 			_M_facets;
     string 				_M_names[_S_num_categories];
     static const locale::id* const 	_S_id_ctype[];
@@ -330,12 +332,12 @@ namespace std
 
     inline void 
     _M_add_reference() throw()
-    { ++_M_references; }  // XXX MT
+    { __atomic_add(&_M_references, 1); }
 
     inline void 
     _M_remove_reference() throw()
     {
-      if (--_M_references == 0)  // XXX MT
+      if (__exchange_and_add(&_M_references, -1) == 1)
 	{
 	  try 
 	    { delete this; } 
@@ -392,7 +394,7 @@ namespace std
     friend class __enc_traits;
 
   private:
-    size_t _M_references;
+    _Atomic_word _M_references;
 
   protected:
     // Contains data from the underlying "C" library for default "C"
@@ -447,7 +449,7 @@ namespace std
     mutable size_t 	_M_index;
 
     // Last id number assigned
-    static size_t 	_S_highwater;   
+    static _Atomic_word 	_S_highwater;   
 
     void 
     operator=(const id&);  // not defined

libstdc++-v3/src/ios.cc

 // Iostreams base classes -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
+// Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -36,6 +37,8 @@
 #include <istream>
 #include <fstream>
 
+#include <bits/atomicity.h>
+
 namespace std 
 {
   // Extern declarations for global objects in src/globals.cc.
@@ -224,10 +227,11 @@ namespace std
   int 
   ios_base::xalloc() throw()
   {
-    // XXX MT
     // XXX should be a symbol. (Reserve 0..3 for builtins.)
-    static int top = 4; 
-    return top++;
+    static _Atomic_word top = 0; 
+    return __exchange_and_add(&top, 1) + 4;
+    // Implementation note: Initialize top to zero to ensure that
+    // initialization occurs before main() is started.
   }
 
   // 27.4.2.5  iword/pword storage

libstdc++-v3/src/locale.cc

@@ -41,6 +41,8 @@
 # include <cwctype>     // for towupper, etc.
 #endif
 
+#include <bits/atomicity.h>
+
 namespace std 
 {
   // Defined in globals.cc.
@@ -72,7 +74,7 @@ namespace std
 #endif
 
   // Definitions for static const data members of locale::id
-  size_t locale::id::_S_highwater;  // init'd to 0 by linker
+  _Atomic_word locale::id::_S_highwater;  // init'd to 0 by linker
 
   // Definitions for static const data members of locale::_Impl
   const locale::id* const
@@ -187,7 +189,7 @@ namespace std
   { 
     _S_initialize(); 
     (_M_impl = _S_global)->_M_add_reference(); 
-  } // XXX MT
+  }
 
   locale::locale(const locale& __other) throw()
   { (_M_impl = __other._M_impl)->_M_add_reference(); }
@@ -283,7 +285,9 @@ namespace std
   locale const&
   locale::classic()
   {
-    // XXX MT
+    static _STL_mutex_lock __lock __STL_MUTEX_INITIALIZER;
+    _STL_auto_lock __auto(__lock);
+
     if (!_S_classic)
       {
 	try 
@@ -364,13 +368,13 @@ namespace std
   void  
   locale::facet::
   _M_add_reference() throw()
-  { ++_M_references; }  // XXX MT
+  { __atomic_add(&_M_references, 1); }
 
   void  
   locale::facet::
   _M_remove_reference() throw()
   {
-    if (_M_references-- == 0)
+    if (__exchange_and_add(&_M_references, -1) == 0)
       {
         try 
 	  { delete this; }  

libstdc++-v3/src/localename.cc

@@ -178,7 +178,7 @@ namespace std
       {
 	size_t& __index = __idp->_M_index;
 	if (!__index)
-	  __index = ++locale::id::_S_highwater;  // XXX MT
+	  __index = 1 + __exchange_and_add(&locale::id::_S_highwater, 1);
 	
 	if (__index >= _M_facets->size())
 	  _M_facets->resize(__index + 1, 0);  // might throw