Thu, 11 Dec 2008 12:05:08 -0800
6578152: fill_region_with_object has usability and safety issues
Reviewed-by: apetrusenko, ysr
duke@435 | 1 | /* |
xdono@631 | 2 | * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | inline OopsInGenClosure::OopsInGenClosure(Generation* gen) : |
duke@435 | 26 | OopClosure(gen->ref_processor()), _orig_gen(gen), _rs(NULL) { |
duke@435 | 27 | set_generation(gen); |
duke@435 | 28 | } |
duke@435 | 29 | |
duke@435 | 30 | inline void OopsInGenClosure::set_generation(Generation* gen) { |
duke@435 | 31 | _gen = gen; |
duke@435 | 32 | _gen_boundary = _gen->reserved().start(); |
duke@435 | 33 | // Barrier set for the heap, must be set after heap is initialized |
duke@435 | 34 | if (_rs == NULL) { |
duke@435 | 35 | GenRemSet* rs = SharedHeap::heap()->rem_set(); |
duke@435 | 36 | assert(rs->rs_kind() == GenRemSet::CardTable, "Wrong rem set kind"); |
duke@435 | 37 | _rs = (CardTableRS*)rs; |
duke@435 | 38 | } |
duke@435 | 39 | } |
duke@435 | 40 | |
coleenp@548 | 41 | template <class T> inline void OopsInGenClosure::do_barrier(T* p) { |
duke@435 | 42 | assert(generation()->is_in_reserved(p), "expected ref in generation"); |
coleenp@548 | 43 | assert(!oopDesc::is_null(*p), "expected non-null object"); |
coleenp@548 | 44 | oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
duke@435 | 45 | // If p points to a younger generation, mark the card. |
duke@435 | 46 | if ((HeapWord*)obj < _gen_boundary) { |
duke@435 | 47 | _rs->inline_write_ref_field_gc(p, obj); |
duke@435 | 48 | } |
duke@435 | 49 | } |
duke@435 | 50 | |
ysr@777 | 51 | inline void OopsInGenClosure::par_do_barrier(oop* p) { |
ysr@777 | 52 | assert(generation()->is_in_reserved(p), "expected ref in generation"); |
ysr@777 | 53 | oop obj = *p; |
ysr@777 | 54 | assert(obj != NULL, "expected non-null object"); |
ysr@777 | 55 | // If p points to a younger generation, mark the card. |
ysr@777 | 56 | if ((HeapWord*)obj < gen_boundary()) { |
ysr@777 | 57 | rs()->write_ref_field_gc_par(p, obj); |
ysr@777 | 58 | } |
ysr@777 | 59 | } |
ysr@777 | 60 | |
duke@435 | 61 | // NOTE! Any changes made here should also be made |
coleenp@548 | 62 | // in FastScanClosure::do_oop_work() |
coleenp@548 | 63 | template <class T> inline void ScanClosure::do_oop_work(T* p) { |
coleenp@548 | 64 | T heap_oop = oopDesc::load_heap_oop(p); |
duke@435 | 65 | // Should we copy the obj? |
coleenp@548 | 66 | if (!oopDesc::is_null(heap_oop)) { |
coleenp@548 | 67 | oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
duke@435 | 68 | if ((HeapWord*)obj < _boundary) { |
duke@435 | 69 | assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?"); |
coleenp@548 | 70 | oop new_obj = obj->is_forwarded() ? obj->forwardee() |
coleenp@548 | 71 | : _g->copy_to_survivor_space(obj); |
coleenp@548 | 72 | oopDesc::encode_store_heap_oop_not_null(p, new_obj); |
duke@435 | 73 | } |
duke@435 | 74 | if (_gc_barrier) { |
duke@435 | 75 | // Now call parent closure |
duke@435 | 76 | do_barrier(p); |
duke@435 | 77 | } |
duke@435 | 78 | } |
duke@435 | 79 | } |
duke@435 | 80 | |
coleenp@548 | 81 | inline void ScanClosure::do_oop_nv(oop* p) { ScanClosure::do_oop_work(p); } |
coleenp@548 | 82 | inline void ScanClosure::do_oop_nv(narrowOop* p) { ScanClosure::do_oop_work(p); } |
duke@435 | 83 | |
duke@435 | 84 | // NOTE! Any changes made here should also be made |
coleenp@548 | 85 | // in ScanClosure::do_oop_work() |
coleenp@548 | 86 | template <class T> inline void FastScanClosure::do_oop_work(T* p) { |
coleenp@548 | 87 | T heap_oop = oopDesc::load_heap_oop(p); |
duke@435 | 88 | // Should we copy the obj? |
coleenp@548 | 89 | if (!oopDesc::is_null(heap_oop)) { |
coleenp@548 | 90 | oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
duke@435 | 91 | if ((HeapWord*)obj < _boundary) { |
duke@435 | 92 | assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?"); |
coleenp@548 | 93 | oop new_obj = obj->is_forwarded() ? obj->forwardee() |
coleenp@548 | 94 | : _g->copy_to_survivor_space(obj); |
coleenp@548 | 95 | oopDesc::encode_store_heap_oop_not_null(p, new_obj); |
duke@435 | 96 | if (_gc_barrier) { |
duke@435 | 97 | // Now call parent closure |
duke@435 | 98 | do_barrier(p); |
duke@435 | 99 | } |
duke@435 | 100 | } |
duke@435 | 101 | } |
duke@435 | 102 | } |
duke@435 | 103 | |
coleenp@548 | 104 | inline void FastScanClosure::do_oop_nv(oop* p) { FastScanClosure::do_oop_work(p); } |
coleenp@548 | 105 | inline void FastScanClosure::do_oop_nv(narrowOop* p) { FastScanClosure::do_oop_work(p); } |
duke@435 | 106 | |
duke@435 | 107 | // Note similarity to ScanClosure; the difference is that |
duke@435 | 108 | // the barrier set is taken care of outside this closure. |
coleenp@548 | 109 | template <class T> inline void ScanWeakRefClosure::do_oop_work(T* p) { |
coleenp@548 | 110 | assert(!oopDesc::is_null(*p), "null weak reference?"); |
coleenp@548 | 111 | oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
duke@435 | 112 | // weak references are sometimes scanned twice; must check |
duke@435 | 113 | // that to-space doesn't already contain this object |
duke@435 | 114 | if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) { |
coleenp@548 | 115 | oop new_obj = obj->is_forwarded() ? obj->forwardee() |
coleenp@548 | 116 | : _g->copy_to_survivor_space(obj); |
coleenp@548 | 117 | oopDesc::encode_store_heap_oop_not_null(p, new_obj); |
duke@435 | 118 | } |
duke@435 | 119 | } |
duke@435 | 120 | |
coleenp@548 | 121 | inline void ScanWeakRefClosure::do_oop_nv(oop* p) { ScanWeakRefClosure::do_oop_work(p); } |
coleenp@548 | 122 | inline void ScanWeakRefClosure::do_oop_nv(narrowOop* p) { ScanWeakRefClosure::do_oop_work(p); } |