[libstdc++] Re-fix generic atomicity.h (was Re: *ping* generic atomicity.h)

[Phil Edwards]

As discussed on the v3 list.  Tested on i686/linux and i386/mingw (thanks
to Danny), no regressions.  Applied to trunk.  I'll apply it to 3.3 in a
couple days, assuming no breakage.


2003-02-12  Phil Edwards  <pme@gcc.gnu.org>

	* config/cpu/generic/atomicity.h (_Atomic_add_mutex):  Fix declaration.
	(_GLIBCPP_NEED_GENERIC_MUTEX):  Define for this file.
	(_Atomic_add_mutex_once, __gthread_atomic_add_mutex_once):  Declare
	when we don't have static mutex initialization.
	(__exchange_and_add):  Use _Atomic_add_mutex_once.
	* src/misc-inst.cc:  Definitions of all the above.


Index: config/cpu/generic/atomicity.h
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/config/cpu/generic/atomicity.h,v
retrieving revision 1.4
diff -u -3 -p -r1.4 atomicity.h
--- config/cpu/generic/atomicity.h	8 Nov 2002 19:24:41 -0000	1.4
+++ config/cpu/generic/atomicity.h	13 Feb 2003 03:54:10 -0000
@@ -1,6 +1,6 @@
 // Low-level functions for atomic operations: Generic version  -*- C++ -*-
 
-// Copyright (C) 1999, 2001, 2002 Free Software Foundation, Inc.
+// Copyright (C) 1999, 2001, 2002, 2003 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
@@ -32,24 +32,35 @@
 
 #include <bits/gthr.h>
 
+#define _GLIBCPP_NEED_GENERIC_MUTEX
+
 typedef int _Atomic_word;
 
 namespace __gnu_cxx
 {
-  __gthread_mutex_t _Atomic_add_mutex __attribute__ ((__weak__))
-                                                      = __GTHREAD_MUTEX_INIT;
+  extern __gthread_mutex_t _Atomic_add_mutex;
+
+#ifndef __GTHREAD_MUTEX_INIT
+  extern __gthread_once_t _Atomic_add_mutex_once;
+  extern void __gthread_atomic_add_mutex_once();
+#endif
 }
 
 static inline _Atomic_word
 __attribute__ ((__unused__))
 __exchange_and_add (volatile _Atomic_word* __mem, int __val)
 {
-   _Atomic_word __result;
+#ifndef __GTHREAD_MUTEX_INIT
+  __gthread_once (&__gnu_cxx::_Atomic_add_mutex_once,
+                  __gnu_cxx::__gthread_atomic_add_mutex_once);
+#endif
+
+  _Atomic_word __result;
 
-   __gthread_mutex_lock (&__gnu_cxx::_Atomic_add_mutex);
+  __gthread_mutex_lock (&__gnu_cxx::_Atomic_add_mutex);
 
-   __result = *__mem;
-   *__mem += __val;
+  __result = *__mem;
+  *__mem += __val;
 
   __gthread_mutex_unlock (&__gnu_cxx::_Atomic_add_mutex);
   return __result;
Index: src/misc-inst.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/src/misc-inst.cc,v
retrieving revision 1.21
diff -u -3 -p -r1.21 misc-inst.cc
--- src/misc-inst.cc	23 Jan 2003 17:21:11 -0000	1.21
+++ src/misc-inst.cc	13 Feb 2003 03:54:10 -0000
@@ -72,3 +72,21 @@ namespace std
   template volatile int __Atomicity_lock<0>::_S_atomicity_lock;
 #endif
 } // namespace std
+
+#ifdef _GLIBCPP_NEED_GENERIC_MUTEX
+namespace __gnu_cxx
+{
+#ifdef __GTHREAD_MUTEX_INIT
+  __gthread_mutex_t _Atomic_add_mutex = __GTHREAD_MUTEX_INIT;
+#else
+  // generic atomicity.h without static initialization
+  __gthread_mutex_t _Atomic_add_mutex;
+  __gthread_once_t _Atomic_add_mutex_once = __GTHREAD_ONCE_INIT;
+  void __gthread_atomic_add_mutex_once()
+  {
+    __GTHREAD_MUTEX_INIT_FUNCTION (&_Atomic_add_mutex);
+  }
+#endif
+} // namespace __gnu_cxx
+#endif // _GLIBCPP_NEED_GLOBAL_MUTEX
+