1/* 2 * Copyright (c) 2016, 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#ifndef SHARE_VM_GC_PARALLEL_OBJECTSTARTARRAY_INLINE_HPP 26#define SHARE_VM_GC_PARALLEL_OBJECTSTARTARRAY_INLINE_HPP 27 28#include "gc/parallel/objectStartArray.hpp" 29 30// Optimized for finding the first object that crosses into 31// a given block. The blocks contain the offset of the last 32// object in that block. Scroll backwards by one, and the first 33// object hit should be at the beginning of the block 34HeapWord* ObjectStartArray::object_start(HeapWord* addr) const { 35 assert_covered_region_contains(addr); 36 jbyte* block = block_for_addr(addr); 37 HeapWord* scroll_forward = offset_addr_for_block(block--); 38 while (scroll_forward > addr) { 39 scroll_forward = offset_addr_for_block(block--); 40 } 41 42 HeapWord* next = scroll_forward; 43 while (next <= addr) { 44 scroll_forward = next; 45 next += oop(next)->size(); 46 } 47 assert(scroll_forward <= addr, "wrong order for current and arg"); 48 assert(addr <= next, "wrong order for arg and next"); 49 return scroll_forward; 50} 51 52 53#endif // SHARE_VM_GC_PARALLEL_OBJECTSTARTARRAY_INLINE_HPP 54