1 /*
2 * Copyright (c) 1998, 2010, 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 "code/oopRecorder.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "oops/oop.inline.hpp"
29
30 #ifdef ASSERT
31 int OopRecorder::_find_index_calls = 0;
32 int OopRecorder::_hit_indexes = 0;
33 int OopRecorder::_missed_indexes = 0;
34 #endif //ASSERT
35
36
37 OopRecorder::OopRecorder(Arena* arena) {
38 _handles = NULL;
39 _indexes = NULL;
40 _arena = arena;
41 _complete = false;
42 }
43
44 OopRecorder::IndexCache::IndexCache() {
45 assert(first_index > 0, "initial zero state of cache must be invalid index");
46 Copy::zero_to_bytes(&_cache[0], sizeof(_cache));
47 }
48
49 int OopRecorder::oop_size() {
50 _complete = true;
51 if (_handles == NULL) return 0;
52 return _handles->length() * sizeof(oop);
53 }
54
55 void OopRecorder::copy_to(nmethod* nm) {
56 assert(_complete, "must be frozen");
57 maybe_initialize(); // get non-null handles, even if we have no oops
58 nm->copy_oops(_handles);
59 }
60
61 void OopRecorder::maybe_initialize() {
62 if (_handles == NULL) {
63 if (_arena != NULL) {
64 _handles = new(_arena) GrowableArray<jobject>(_arena, 10, 0, 0);
65 _no_finds = new(_arena) GrowableArray<int>( _arena, 10, 0, 0);
66 } else {
67 _handles = new GrowableArray<jobject>(10, 0, 0);
68 _no_finds = new GrowableArray<int>( 10, 0, 0);
69 }
70 }
71 }
72
73
74 jobject OopRecorder::handle_at(int index) {
75 // there is always a NULL virtually present as first object
76 if (index == null_index) return NULL;
77 return _handles->at(index - first_index);
78 }
79
80
81 // Local definition. Used only in this module.
82 inline bool OopRecorder::is_real_jobject(jobject h) {
83 return h != NULL && h != (jobject)Universe::non_oop_word();
84 }
85
86
87 int OopRecorder::add_handle(jobject h, bool make_findable) {
88 assert(!_complete, "cannot allocate more elements after size query");
89 maybe_initialize();
90 // indexing uses 1 as an origin--0 means null
91 int index = _handles->length() + first_index;
92 _handles->append(h);
93
94 // Support correct operation of find_index().
95 assert(!(make_findable && !is_real_jobject(h)), "nulls are not findable");
96 if (make_findable) {
97 // This index may be returned from find_index().
98 if (_indexes != NULL) {
99 int* cloc = _indexes->cache_location(h);
100 _indexes->set_cache_location_index(cloc, index);
101 } else if (index == index_cache_threshold && _arena != NULL) {
102 _indexes = new(_arena) IndexCache();
103 for (int i = 0; i < _handles->length(); i++) {
104 // Load the cache with pre-existing elements.
105 int index0 = i + first_index;
106 if (_no_finds->contains(index0)) continue;
107 int* cloc = _indexes->cache_location(_handles->at(i));
108 _indexes->set_cache_location_index(cloc, index0);
109 }
110 }
111 } else if (is_real_jobject(h)) {
112 // Remember that this index is not to be returned from find_index().
113 // This case is rare, because most or all uses of allocate_index pass
114 // a jobject argument of NULL or Universe::non_oop_word.
115 // Thus, the expected length of _no_finds is zero.
116 _no_finds->append(index);
117 }
118
119 return index;
120 }
121
122
123 int OopRecorder::maybe_find_index(jobject h) {
124 debug_only(_find_index_calls++);
125 assert(!_complete, "cannot allocate more elements after size query");
126 maybe_initialize();
127 if (h == NULL) return null_index;
128 assert(is_real_jobject(h), "must be valid jobject");
129 int* cloc = (_indexes == NULL)? NULL: _indexes->cache_location(h);
130 if (cloc != NULL) {
131 int cindex = _indexes->cache_location_index(cloc);
132 if (cindex == 0) {
133 return -1; // We know this handle is completely new.
134 }
135 if (cindex >= first_index && _handles->at(cindex - first_index) == h) {
136 debug_only(_hit_indexes++);
137 return cindex;
138 }
139 if (!_indexes->cache_location_collision(cloc)) {
140 return -1; // We know the current cache occupant is unique to that cloc.
141 }
142 }
143
144 // Not found in cache, due to a cache collision. (Or, no cache at all.)
145 // Do a linear search, most recent to oldest.
146 for (int i = _handles->length() - 1; i >= 0; i--) {
147 if (_handles->at(i) == h) {
148 int findex = i + first_index;
149 if (_no_finds->contains(findex)) continue; // oops; skip this one
150 if (cloc != NULL) {
151 _indexes->set_cache_location_index(cloc, findex);
152 }
153 debug_only(_missed_indexes++);
154 return findex;
155 }
156 }
157 return -1;
158 }