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8198313: Wrap holder object for ClassLoaderData in a WeakHandle

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Use WeakHandle for ClassLoaderData::_holder so that is_alive closure is not needed

Reviewed-by: rehn, kbarrett
This commit is contained in:
Coleen Phillimore 2018-04-10 10:06:42 -04:00
parent 21f636f3cf
commit d187884156
13 changed files with 273 additions and 48 deletions
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71
src/hotspot/share/oops/weakHandle.cpp Normal file
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/*
* Copyright (c) 2018, 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 "classfile/systemDictionary.hpp"
#include "gc/shared/oopStorage.hpp"
#include "oops/access.inline.hpp"
#include "oops/oop.hpp"
#include "oops/weakHandle.inline.hpp"
#include "utilities/debug.hpp"
#include "utilities/ostream.hpp"
template <> OopStorage* WeakHandle<vm_class_loader_data>::get_storage() {
return SystemDictionary::vm_weak_oop_storage();
}
template <WeakHandleType T>
WeakHandle<T> WeakHandle<T>::create(Handle obj) {
assert(obj() != NULL, "no need to create weak null oop");
oop* oop_addr = get_storage()->allocate();
if (oop_addr == NULL) {
vm_exit_out_of_memory(sizeof(oop*), OOM_MALLOC_ERROR, "Unable to create new weak oop handle in OopStorage");
}
// Create WeakHandle with address returned and store oop into it.
RootAccess<ON_PHANTOM_OOP_REF>::oop_store(oop_addr, obj());
return WeakHandle(oop_addr);
}
template <WeakHandleType T>
void WeakHandle<T>::release() const {
// Only release if the pointer to the object has been created.
if (_obj != NULL) {
// Clear the WeakHandle. For class loader data race, the handle may not have
// been previously cleared by GC.
RootAccess<ON_PHANTOM_OOP_REF>::oop_store(_obj, (oop)NULL);
get_storage()->release(_obj);
}
}
template <WeakHandleType T>
void WeakHandle<T>::print() const { print_on(tty); }
template <WeakHandleType T>
void WeakHandle<T>::print_on(outputStream* st) const {
st->print("WeakHandle: " PTR_FORMAT, p2i(peek()));
}
// Provide instantiation.
template class WeakHandle<vm_class_loader_data>;