1 /*
2 * Copyright (c) 2017, 2018, 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 "classfile/protectionDomainCache.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "logging/log.hpp"
29 #include "logging/logStream.hpp"
30 #include "memory/iterator.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "utilities/hashtable.inline.hpp"
34
35 unsigned int ProtectionDomainCacheTable::compute_hash(Handle protection_domain) {
36 // Identity hash can safepoint, so keep protection domain in a Handle.
37 return (unsigned int)(protection_domain->identity_hash());
38 }
39
40 int ProtectionDomainCacheTable::index_for(Handle protection_domain) {
41 return hash_to_index(compute_hash(protection_domain));
42 }
43
44 ProtectionDomainCacheTable::ProtectionDomainCacheTable(int table_size)
45 : Hashtable<oop, mtClass>(table_size, sizeof(ProtectionDomainCacheEntry))
46 {
47 }
48
49 void ProtectionDomainCacheTable::unlink(BoolObjectClosure* is_alive) {
50 assert(SafepointSynchronize::is_at_safepoint(), "must be");
51 for (int i = 0; i < table_size(); ++i) {
52 ProtectionDomainCacheEntry** p = bucket_addr(i);
53 ProtectionDomainCacheEntry* entry = bucket(i);
54 while (entry != NULL) {
55 if (is_alive->do_object_b(entry->object_no_keepalive())) {
56 p = entry->next_addr();
57 } else {
58 LogTarget(Debug, protectiondomain) lt;
59 if (lt.is_enabled()) {
60 LogStream ls(lt);
61 ls.print("protection domain unlinked: ");
62 entry->object_no_keepalive()->print_value_on(&ls);
63 ls.cr();
64 }
65 *p = entry->next();
66 free_entry(entry);
67 }
68 entry = *p;
69 }
70 }
71 }
72
73 void ProtectionDomainCacheTable::oops_do(OopClosure* f) {
74 for (int index = 0; index < table_size(); index++) {
75 for (ProtectionDomainCacheEntry* probe = bucket(index);
76 probe != NULL;
77 probe = probe->next()) {
78 probe->oops_do(f);
79 }
80 }
81 }
82
83 void ProtectionDomainCacheTable::print_on(outputStream* st) const {
84 st->print_cr("Protection domain cache table (table_size=%d, classes=%d)",
85 table_size(), number_of_entries());
86 for (int index = 0; index < table_size(); index++) {
87 for (ProtectionDomainCacheEntry* probe = bucket(index);
88 probe != NULL;
89 probe = probe->next()) {
90 st->print_cr("%4d: protection_domain: " PTR_FORMAT, index, p2i(probe->object_no_keepalive()));
91 }
92 }
93 }
94
95 void ProtectionDomainCacheTable::verify() {
96 verify_table<ProtectionDomainCacheEntry>("Protection Domain Table");
97 }
98
99 oop ProtectionDomainCacheEntry::object() {
100 return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(literal_addr());
101 }
102
103 oop ProtectionDomainEntry::object() {
104 return _pd_cache->object();
105 }
106
107 // The object_no_keepalive() call peeks at the phantomly reachable oop without
108 // keeping it alive. This is okay to do in the VM thread state if it is not
109 // leaked out to become strongly reachable.
110 oop ProtectionDomainCacheEntry::object_no_keepalive() {
111 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(literal_addr());
112 }
113
114 oop ProtectionDomainEntry::object_no_keepalive() {
115 return _pd_cache->object_no_keepalive();
116 }
117
118 void ProtectionDomainCacheEntry::verify() {
119 guarantee(oopDesc::is_oop(object_no_keepalive()), "must be an oop");
120 }
121
122 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::get(Handle protection_domain) {
123 unsigned int hash = compute_hash(protection_domain);
124 int index = hash_to_index(hash);
125
126 ProtectionDomainCacheEntry* entry = find_entry(index, protection_domain);
127 if (entry == NULL) {
128 entry = add_entry(index, hash, protection_domain);
129 }
130 return entry;
131 }
132
133 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::find_entry(int index, Handle protection_domain) {
134 for (ProtectionDomainCacheEntry* e = bucket(index); e != NULL; e = e->next()) {
135 if (e->object_no_keepalive() == protection_domain()) {
136 return e;
137 }
138 }
139
140 return NULL;
141 }
142
143 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::add_entry(int index, unsigned int hash, Handle protection_domain) {
144 assert_locked_or_safepoint(SystemDictionary_lock);
145 assert(index == index_for(protection_domain), "incorrect index?");
146 assert(find_entry(index, protection_domain) == NULL, "no double entry");
147
148 ProtectionDomainCacheEntry* p = new_entry(hash, protection_domain);
149 Hashtable<oop, mtClass>::add_entry(index, p);
150 return p;
151 }