1 /*
2 * Copyright (c) 2020, 2025, 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 "cds/cdsConfig.hpp"
26 #include "cds/serializeClosure.hpp"
27 #include "classfile/classLoaderData.inline.hpp"
28 #include "classfile/classLoaderDataShared.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/modules.hpp"
31 #include "classfile/packageEntry.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "logging/log.hpp"
34 #include "runtime/handles.inline.hpp"
35 #include "runtime/safepoint.hpp"
36
37 #if INCLUDE_CDS_JAVA_HEAP
38
39 bool ClassLoaderDataShared::_full_module_graph_loaded = false;
40
41 class ArchivedClassLoaderData {
42 Array<PackageEntry*>* _packages;
43 Array<ModuleEntry*>* _modules;
44
45 void assert_valid(ClassLoaderData* loader_data) {
46 // loader_data may be null if the boot layer has loaded no modules for the platform or
47 // system loaders (e.g., if you create a custom JDK image with only java.base).
48 if (loader_data != nullptr) {
49 assert(!loader_data->has_class_mirror_holder(),
50 "loaders for non-strong hidden classes not supported");
51 }
52 }
53 public:
54 ArchivedClassLoaderData() : _packages(nullptr), _modules(nullptr) {}
55
56 void iterate_symbols(ClassLoaderData* loader_data, MetaspaceClosure* closure);
57 void allocate(ClassLoaderData* loader_data);
58 void init_archived_entries(ClassLoaderData* loader_data);
59
60 void serialize(SerializeClosure* f) {
61 f->do_ptr(&_packages);
62 f->do_ptr(&_modules);
63 }
64
65 void restore(ClassLoaderData* loader_data, bool do_entries, bool do_oops);
66 void clear_archived_oops();
67 };
68
69 static ArchivedClassLoaderData _archived_boot_loader_data;
70 static ArchivedClassLoaderData _archived_platform_loader_data;
71 static ArchivedClassLoaderData _archived_system_loader_data;
72 static ModuleEntry* _archived_javabase_moduleEntry = nullptr;
73
74 void ArchivedClassLoaderData::iterate_symbols(ClassLoaderData* loader_data, MetaspaceClosure* closure) {
75 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
76 assert_valid(loader_data);
77 if (loader_data != nullptr) {
78 loader_data->packages()->iterate_symbols(closure);
79 loader_data->modules() ->iterate_symbols(closure);
80 }
81 }
82
83 void ArchivedClassLoaderData::allocate(ClassLoaderData* loader_data) {
84 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
85 assert_valid(loader_data);
86 if (loader_data != nullptr) {
87 // We can't create hashtables at dump time because the hashcode depends on the
88 // address of the Symbols, which may be relocated at runtime due to ASLR.
89 // So we store the packages/modules in Arrays. At runtime, we create
90 // the hashtables using these arrays.
91 _packages = loader_data->packages()->allocate_archived_entries();
92 _modules = loader_data->modules() ->allocate_archived_entries();
93 }
94 }
95
96 void ArchivedClassLoaderData::init_archived_entries(ClassLoaderData* loader_data) {
97 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
98 assert_valid(loader_data);
99 if (loader_data != nullptr) {
100 loader_data->packages()->init_archived_entries(_packages);
101 loader_data->modules() ->init_archived_entries(_modules);
102 }
103 }
104
105 void ArchivedClassLoaderData::restore(ClassLoaderData* loader_data, bool do_entries, bool do_oops) {
106 assert(CDSConfig::is_using_archive(), "must be");
107 assert_valid(loader_data);
108 if (_modules != nullptr) { // Could be null if we have archived no modules for platform/system loaders
109 ModuleEntryTable* modules = loader_data->modules();
110 PackageEntryTable* packages = loader_data->packages();
111
112 MutexLocker m1(Module_lock);
113 if (do_entries) {
114 modules->load_archived_entries(loader_data, _modules);
115 packages->load_archived_entries(_packages);
116 }
117 if (do_oops) {
118 modules->restore_archived_oops(loader_data, _modules);
119 }
120 }
121 }
122
123 void ArchivedClassLoaderData::clear_archived_oops() {
124 assert(CDSConfig::is_using_archive(), "must be");
125 if (_modules != nullptr) {
126 for (int i = 0; i < _modules->length(); i++) {
127 _modules->at(i)->clear_archived_oops();
128 }
129 }
130 }
131
132 // ------------------------------
133
134 static ClassLoaderData* null_class_loader_data() {
135 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
136 assert(loader_data != nullptr, "must be");
137 return loader_data;
138 }
139
140 static ClassLoaderData* java_platform_loader_data_or_null() {
141 return ClassLoaderData::class_loader_data_or_null(SystemDictionary::java_platform_loader());
142 }
143
144 static ClassLoaderData* java_system_loader_data_or_null() {
145 return ClassLoaderData::class_loader_data_or_null(SystemDictionary::java_system_loader());
146 }
147
148 // ModuleEntryTables (even if empty) are required for iterate_symbols() to scan the
149 // platform/system loaders inside the CDS safepoint, but the tables can be created only
150 // when outside of safepoints. Let's do that now.
151 void ClassLoaderDataShared::ensure_module_entry_tables_exist() {
152 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
153 ensure_module_entry_table_exists(SystemDictionary::java_platform_loader());
154 ensure_module_entry_table_exists(SystemDictionary::java_system_loader());
155 }
156
157 void ClassLoaderDataShared::ensure_module_entry_table_exists(oop class_loader) {
158 Handle h_loader(JavaThread::current(), class_loader);
159 ModuleEntryTable* met = Modules::get_module_entry_table(h_loader);
160 assert(met != nullptr, "sanity");
161 }
162
163 void ClassLoaderDataShared::iterate_symbols(MetaspaceClosure* closure) {
164 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
165 _archived_boot_loader_data.iterate_symbols (null_class_loader_data(), closure);
166 _archived_platform_loader_data.iterate_symbols(java_platform_loader_data_or_null(), closure);
167 _archived_system_loader_data.iterate_symbols (java_system_loader_data_or_null(), closure);
168 }
169
170 void ClassLoaderDataShared::allocate_archived_tables() {
171 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
172 _archived_boot_loader_data.allocate (null_class_loader_data());
173 _archived_platform_loader_data.allocate(java_platform_loader_data_or_null());
174 _archived_system_loader_data.allocate (java_system_loader_data_or_null());
175 }
176
177 void ClassLoaderDataShared::init_archived_tables() {
178 assert(CDSConfig::is_dumping_full_module_graph(), "must be");
179 _archived_boot_loader_data.init_archived_entries (null_class_loader_data());
180 _archived_platform_loader_data.init_archived_entries(java_platform_loader_data_or_null());
181 _archived_system_loader_data.init_archived_entries (java_system_loader_data_or_null());
182 _archived_javabase_moduleEntry = ModuleEntry::get_archived_entry(ModuleEntryTable::javabase_moduleEntry());
183 }
184
185 void ClassLoaderDataShared::serialize(SerializeClosure* f) {
186 _archived_boot_loader_data.serialize(f);
187 _archived_platform_loader_data.serialize(f);
188 _archived_system_loader_data.serialize(f);
189 f->do_ptr(&_archived_javabase_moduleEntry);
190
191 if (f->reading() && CDSConfig::is_using_full_module_graph()) {
192 // Must be done before ClassLoader::create_javabase()
193 _archived_boot_loader_data.restore(null_class_loader_data(), true, false);
194 ModuleEntryTable::set_javabase_moduleEntry(_archived_javabase_moduleEntry);
195 log_info(cds)("use_full_module_graph = true; java.base = " INTPTR_FORMAT,
196 p2i(_archived_javabase_moduleEntry));
197 }
198 }
199
200 void ClassLoaderDataShared::clear_archived_oops() {
201 assert(!CDSConfig::is_using_full_module_graph(), "must be");
202 _archived_boot_loader_data.clear_archived_oops();
203 _archived_platform_loader_data.clear_archived_oops();
204 _archived_system_loader_data.clear_archived_oops();
205 }
206
207 oop ClassLoaderDataShared::restore_archived_oops_for_null_class_loader_data() {
208 assert(CDSConfig::is_using_full_module_graph(), "must be");
209 _archived_boot_loader_data.restore(null_class_loader_data(), false, true);
210 return _archived_javabase_moduleEntry->module();
211 }
212
213 void ClassLoaderDataShared::restore_java_platform_loader_from_archive(ClassLoaderData* loader_data) {
214 assert(CDSConfig::is_using_full_module_graph(), "must be");
215 _archived_platform_loader_data.restore(loader_data, true, true);
216 }
217
218 void ClassLoaderDataShared::restore_java_system_loader_from_archive(ClassLoaderData* loader_data) {
219 assert(CDSConfig::is_using_full_module_graph(), "must be");
220 _archived_system_loader_data.restore(loader_data, true, true);
221 _full_module_graph_loaded = true;
222 }
223
224 #endif // INCLUDE_CDS_JAVA_HEAP