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