1 /* 2 * Copyright (c) 2015, 2019, Red Hat, Inc. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP 27 28 #include "gc/shenandoah/shenandoahAsserts.hpp" 29 #include "gc/shenandoah/shenandoahForwarding.hpp" 30 #include "oops/markWord.inline.hpp" 31 #include "runtime/thread.hpp" 32 33 inline HeapWord* ShenandoahForwarding::get_forwardee_raw(oop obj) { 34 shenandoah_assert_in_heap(NULL, obj); 35 return get_forwardee_raw_unchecked(obj); 36 } 37 38 inline HeapWord* ShenandoahForwarding::get_forwardee_raw_unchecked(oop obj) { 39 // JVMTI and JFR code use mark words for marking objects for their needs. 40 // On this path, we can encounter the "marked" object, but with NULL 41 // fwdptr. That object is still not forwarded, and we need to return 42 // the object itself. 43 markWord mark = obj->mark_raw(); 44 if (mark.is_marked()) { 45 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer(); 46 if (fwdptr != NULL) { 47 return fwdptr; 48 } 49 } 50 return cast_from_oop<HeapWord*>(obj); 51 } 52 53 inline oop ShenandoahForwarding::get_forwardee_mutator(oop obj) { 54 // Same as above, but mutator thread cannot ever see NULL forwardee. 55 shenandoah_assert_correct(NULL, obj); 56 assert(Thread::current()->is_Java_thread(), "Must be a mutator thread"); 57 58 markWord mark = obj->mark_raw(); 59 if (mark.is_marked()) { 60 HeapWord* fwdptr = (HeapWord*) mark.clear_lock_bits().to_pointer(); 61 assert(fwdptr != NULL, "Forwarding pointer is never null here"); 62 return cast_to_oop(fwdptr); 63 } else { 64 return obj; 65 } 66 } 67 68 inline oop ShenandoahForwarding::get_forwardee(oop obj) { 69 shenandoah_assert_correct(NULL, obj); 70 return oop(get_forwardee_raw_unchecked(obj)); 71 } 72 73 inline bool ShenandoahForwarding::is_forwarded(oop obj) { 74 return obj->mark_raw().is_marked(); 75 } 76 77 inline void ShenandoahForwarding::update_forwardee(oop obj, oop update) { 78 markWord old_mark = obj->mark_raw(); 79 markWord new_mark = markWord::encode_pointer_as_mark(update); 80 obj->set_mark_raw(new_mark); 81 } 82 83 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHFORWARDING_INLINE_HPP