8282469: Allow considered use of C++ thread_local in Hotspot

Reviewed-by: kbarrett, dcubed

src/hotspot/share/memory/operator_new.cpp

@@ -1,100 +0,0 @@
-/*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- *
- */
-
-#include "precompiled.hpp"
-#include "utilities/debug.hpp"
-
-#include <new>
-
-//--------------------------------------------------------------------------------------
-// Non-product code
-
-#ifndef PRODUCT
-// The global operator new should never be called since it will usually indicate
-// a memory leak.  Use CHeapObj as the base class of such objects to make it explicit
-// that they're allocated on the C heap.
-// Commented out in product version to avoid conflicts with third-party C++ native code.
-//
-// In C++98/03 the throwing new operators are defined with the following signature:
-//
-// void* operator new(std::size_tsize) throw(std::bad_alloc);
-// void* operator new[](std::size_tsize) throw(std::bad_alloc);
-//
-// while all the other (non-throwing) new and delete operators are defined with an empty
-// throw clause (i.e. "operator delete(void* p) throw()") which means that they do not
-// throw any exceptions (see section 18.4 of the C++ standard).
-//
-// In the new C++11/14 standard, the signature of the throwing new operators was changed
-// by completely omitting the throw clause (which effectively means they could throw any
-// exception) while all the other new/delete operators where changed to have a 'nothrow'
-// clause instead of an empty throw clause.
-//
-// Unfortunately, the support for exception specifications among C++ compilers is still
-// very fragile. While some more strict compilers like AIX xlC or HP aCC reject to
-// override the default throwing new operator with a user operator with an empty throw()
-// clause, the MS Visual C++ compiler warns for every non-empty throw clause like
-// throw(std::bad_alloc) that it will ignore the exception specification. The following
-// operator definitions have been checked to correctly work with all currently supported
-// compilers and they should be upwards compatible with C++11/14. Therefore
-// PLEASE BE CAREFUL if you change the signature of the following operators!
-
-static void * zero = (void *) 0;
-
-void* operator new(size_t size) /* throw(std::bad_alloc) */ {
-  fatal("Should not call global operator new");
-  return zero;
-}
-
-void* operator new [](size_t size) /* throw(std::bad_alloc) */ {
-  fatal("Should not call global operator new[]");
-  return zero;
-}
-
-void* operator new(size_t size, const std::nothrow_t&  nothrow_constant) throw() {
-  fatal("Should not call global operator new");
-  return 0;
-}
-
-void* operator new [](size_t size, std::nothrow_t&  nothrow_constant) throw() {
-  fatal("Should not call global operator new[]");
-  return 0;
-}
-
-void operator delete(void* p) throw() {
-  fatal("Should not call global delete");
-}
-
-void operator delete [](void* p) throw() {
-  fatal("Should not call global delete []");
-}
-
-void operator delete(void* p, size_t size) throw() {
-  fatal("Should not call global sized delete");
-}
-
-void operator delete [](void* p, size_t size) throw() {
-  fatal("Should not call global sized delete []");
-}
-
-#endif // Non-product

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -1219,5 +1219,9 @@ template<typename K> bool primitive_equals(const K& k0, const K& k1) {
   return k0 == k1;
 }
 
+//----------------------------------------------------------------------------------------------------
+
+// Allow use of C++ thread_local when approved - see JDK-8282469.
+#define APPROVED_CPP_THREAD_LOCAL thread_local
 
 #endif // SHARE_UTILITIES_GLOBALDEFINITIONS_HPP