1/*
2 * Copyright (c) 2001, 2017, 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#include "precompiled.hpp"
26#include "gc/cms/freeChunk.hpp"
27#include "utilities/copy.hpp"
28
29#ifndef PRODUCT
30
31#define baadbabeHeapWord badHeapWordVal
32#define deadbeefHeapWord 0xdeadbeef
33
34size_t const FreeChunk::header_size() {
35 return sizeof(FreeChunk)/HeapWordSize;
36}
37
38void FreeChunk::mangleAllocated(size_t size) {
39 // mangle all but the header of a just-allocated block
40 // of storage
41 assert(size >= MinChunkSize, "smallest size of object");
42 // we can't assert that _size == size because this may be an
43 // allocation out of a linear allocation block
44 assert(sizeof(FreeChunk) % HeapWordSize == 0,
45 "shouldn't write beyond chunk");
46 HeapWord* addr = (HeapWord*)this;
47 size_t hdr = header_size();
48 Copy::fill_to_words(addr + hdr, size - hdr, baadbabeHeapWord);
49}
50
51void FreeChunk::mangleFreed(size_t sz) {
52 assert(baadbabeHeapWord != deadbeefHeapWord, "Need distinct patterns");
53 // mangle all but the header of a just-freed block of storage
54 // just prior to passing it to the storage dictionary
55 assert(sz >= MinChunkSize, "smallest size of object");
56 assert(sz == size(), "just checking");
57 HeapWord* addr = (HeapWord*)this;
58 size_t hdr = header_size();
59 Copy::fill_to_words(addr + hdr, sz - hdr, deadbeefHeapWord);
60}
61
62void FreeChunk::verifyList() const {
63 FreeChunk* nextFC = next();
64 if (nextFC != NULL) {
65 assert(this == nextFC->prev(), "broken chain");
66 assert(size() == nextFC->size(), "wrong size");
67 nextFC->verifyList();
68 }
69}
70#endif
71
72void FreeChunk::print_on(outputStream* st) {
73 st->print_cr("Next: " PTR_FORMAT " Prev: " PTR_FORMAT " %s",
74 p2i(next()), p2i(prev()), cantCoalesce() ? "[can't coalesce]" : "");
75}
76