1 /*
2 * Copyright 1998-2010 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_oopRecorder.cpp.incl"
27
28 #ifdef ASSERT
29 int OopRecorder::_find_index_calls = 0;
30 int OopRecorder::_hit_indexes = 0;
31 int OopRecorder::_missed_indexes = 0;
32 #endif //ASSERT
33
34
35 OopRecorder::OopRecorder(Arena* arena) {
36 _handles = NULL;
37 _indexes = NULL;
38 _arena = arena;
39 _complete = false;
40 }
41
42 OopRecorder::IndexCache::IndexCache() {
43 assert(first_index > 0, "initial zero state of cache must be invalid index");
44 Copy::zero_to_bytes(&_cache[0], sizeof(_cache));
45 }
46
47 int OopRecorder::oop_size() {
48 _complete = true;
49 if (_handles == NULL) return 0;
50 return _handles->length() * sizeof(oop);
51 }
52
53 void OopRecorder::copy_to(nmethod* nm) {
54 assert(_complete, "must be frozen");
55 maybe_initialize(); // get non-null handles, even if we have no oops
56 nm->copy_oops(_handles);
57 }
58
59 void OopRecorder::maybe_initialize() {
60 if (_handles == NULL) {
61 if (_arena != NULL) {
62 _handles = new(_arena) GrowableArray<jobject>(_arena, 10, 0, 0);
63 _no_finds = new(_arena) GrowableArray<int>( _arena, 10, 0, 0);
64 } else {
65 _handles = new GrowableArray<jobject>(10, 0, 0);
66 _no_finds = new GrowableArray<int>( 10, 0, 0);
67 }
68 }
69 }
70
71
72 jobject OopRecorder::handle_at(int index) {
73 // there is always a NULL virtually present as first object
74 if (index == null_index) return NULL;
75 return _handles->at(index - first_index);
76 }
77
78
79 // Local definition. Used only in this module.
80 inline bool OopRecorder::is_real_jobject(jobject h) {
81 return h != NULL && h != (jobject)Universe::non_oop_word();
82 }
83
84
85 int OopRecorder::add_handle(jobject h, bool make_findable) {
86 assert(!_complete, "cannot allocate more elements after size query");
87 maybe_initialize();
88 // indexing uses 1 as an origin--0 means null
89 int index = _handles->length() + first_index;
90 _handles->append(h);
91
92 // Support correct operation of find_index().
93 assert(!(make_findable && !is_real_jobject(h)), "nulls are not findable");
94 if (make_findable) {
95 // This index may be returned from find_index().
96 if (_indexes != NULL) {
97 int* cloc = _indexes->cache_location(h);
98 _indexes->set_cache_location_index(cloc, index);
99 } else if (index == index_cache_threshold && _arena != NULL) {
100 _indexes = new(_arena) IndexCache();
101 for (int i = 0; i < _handles->length(); i++) {
102 // Load the cache with pre-existing elements.
103 int index0 = i + first_index;
104 if (_no_finds->contains(index0)) continue;
105 int* cloc = _indexes->cache_location(_handles->at(i));
106 _indexes->set_cache_location_index(cloc, index0);
107 }
108 }
109 } else if (is_real_jobject(h)) {
110 // Remember that this index is not to be returned from find_index().
111 // This case is rare, because most or all uses of allocate_index pass
112 // a jobject argument of NULL or Universe::non_oop_word.
113 // Thus, the expected length of _no_finds is zero.
114 _no_finds->append(index);
115 }
116
117 return index;
118 }
119
120
121 int OopRecorder::maybe_find_index(jobject h) {
122 debug_only(_find_index_calls++);
123 assert(!_complete, "cannot allocate more elements after size query");
124 maybe_initialize();
125 if (h == NULL) return null_index;
126 assert(is_real_jobject(h), "must be valid jobject");
127 int* cloc = (_indexes == NULL)? NULL: _indexes->cache_location(h);
128 if (cloc != NULL) {
129 int cindex = _indexes->cache_location_index(cloc);
130 if (cindex == 0) {
131 return -1; // We know this handle is completely new.
132 }
133 if (cindex >= first_index && _handles->at(cindex - first_index) == h) {
134 debug_only(_hit_indexes++);
135 return cindex;
136 }
137 if (!_indexes->cache_location_collision(cloc)) {
138 return -1; // We know the current cache occupant is unique to that cloc.
139 }
140 }
141
142 // Not found in cache, due to a cache collision. (Or, no cache at all.)
143 // Do a linear search, most recent to oldest.
144 for (int i = _handles->length() - 1; i >= 0; i--) {
145 if (_handles->at(i) == h) {
146 int findex = i + first_index;
147 if (_no_finds->contains(findex)) continue; // oops; skip this one
148 if (cloc != NULL) {
149 _indexes->set_cache_location_index(cloc, findex);
150 }
151 debug_only(_missed_indexes++);
152 return findex;
153 }
154 }
155 return -1;
156 }