1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. 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 package sun.jvm.hotspot.gc.z; 26 27 import sun.jvm.hotspot.debugger.Address; 28 import sun.jvm.hotspot.runtime.VM; 29 30 class ZBarrier { 31 private static boolean is_weak_good_or_null_fast_path(Address addr) { 32 return ZAddress.is_weak_good_or_null(addr); 33 } 34 35 private static Address weak_load_barrier_on_oop_slow_path(Address addr) { 36 return ZAddress.is_weak_good(addr) ? ZAddress.good(addr) : relocate_or_remap(addr); 37 } 38 39 private static boolean during_relocate() { 40 return ZGlobals.ZGlobalPhase() == ZGlobals.ZPhaseRelocate; 41 } 42 43 private static Address relocate(Address addr) { 44 ZHeap heap = zheap(); 45 if (heap.is_relocating(addr)) { 46 // Forward 47 return heap.relocate_object(addr); 48 } 49 50 // Remap 51 return ZAddress.good(addr); 52 } 53 54 private static ZHeap zheap() { 55 ZCollectedHeap zCollectedHeap = (ZCollectedHeap)VM.getVM().getUniverse().heap(); 56 return zCollectedHeap.heap(); 57 } 58 59 private static Address remap(Address addr) { 60 ZHeap heap = zheap(); 61 if (heap.is_relocating(addr)) { 62 // Forward 63 return heap.forward_object(addr); 64 } 65 66 // Remap 67 return ZAddress.good(addr); 68 } 69 70 private static Address relocate_or_remap(Address addr) { 71 return during_relocate() ? relocate(addr) : remap(addr); 72 } 73 74 static Address weak_barrier(Address o) { 75 // Fast path 76 if (is_weak_good_or_null_fast_path(o)) { 77 // Return the good address instead of the weak good address 78 // to ensure that the currently active heap view is used. 79 return ZAddress.good_or_null(o); 80 } 81 82 // Slow path 83 return weak_load_barrier_on_oop_slow_path(o); 84 } 85 }