93 lines
3.3 KiB
C++
93 lines
3.3 KiB
C++
/*
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* Copyright (c) 2015, 2019, Red Hat, Inc. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
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#define SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
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#include "gc/shenandoah/shenandoahAsserts.hpp"
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#include "gc/shenandoah/shenandoahForwarding.hpp"
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#include "oops/markWord.inline.hpp"
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#include "runtime/thread.hpp"
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inline HeapWord* ShenandoahForwarding::get_forwardee_raw(oop obj) {
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shenandoah_assert_in_heap(NULL, obj);
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return get_forwardee_raw_unchecked(obj);
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}
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inline HeapWord* ShenandoahForwarding::get_forwardee_raw_unchecked(oop obj) {
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// JVMTI and JFR code use mark words for marking objects for their needs.
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// On this path, we can encounter the "marked" object, but with NULL
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// fwdptr. That object is still not forwarded, and we need to return
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// the object itself.
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markWord mark = obj->mark_raw();
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if (mark.is_marked()) {
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HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
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if (fwdptr != NULL) {
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return fwdptr;
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}
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}
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return cast_from_oop<HeapWord*>(obj);
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}
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inline oop ShenandoahForwarding::get_forwardee_mutator(oop obj) {
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// Same as above, but mutator thread cannot ever see NULL forwardee.
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shenandoah_assert_correct(NULL, obj);
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assert(Thread::current()->is_Java_thread(), "Must be a mutator thread");
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markWord mark = obj->mark_raw();
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if (mark.is_marked()) {
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HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer();
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assert(fwdptr != NULL, "Forwarding pointer is never null here");
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return cast_to_oop(fwdptr);
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} else {
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return obj;
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}
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}
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inline oop ShenandoahForwarding::get_forwardee(oop obj) {
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shenandoah_assert_correct(NULL, obj);
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return oop(get_forwardee_raw_unchecked(obj));
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}
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inline bool ShenandoahForwarding::is_forwarded(oop obj) {
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return obj->mark_raw().is_marked();
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}
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inline oop ShenandoahForwarding::try_update_forwardee(oop obj, oop update) {
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markWord old_mark = obj->mark_raw();
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if (old_mark.is_marked()) {
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return oop(old_mark.clear_lock_bits().to_pointer());
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}
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markWord new_mark = markWord::encode_pointer_as_mark(update);
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markWord prev_mark = obj->cas_set_mark_raw(new_mark, old_mark);
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if (prev_mark == old_mark) {
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return update;
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} else {
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return oop(prev_mark.clear_lock_bits().to_pointer());
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}
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}
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#endif // SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP
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