1 /*
2 * Copyright (c) 2021, 2024, 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 "cds/archiveHeapLoader.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/aotLinkedClassBulkLoader.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.hpp"
31 #include "classfile/dictionary.hpp"
32 #include "classfile/javaClasses.hpp"
33 #include "classfile/systemDictionary.hpp"
34 #include "classfile/vmClasses.hpp"
35 #include "classfile/vmSymbols.hpp"
36 #include "gc/shared/collectedHeap.hpp"
37 #include "memory/metaspaceClosure.hpp"
38 #include "memory/universe.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/instanceStackChunkKlass.hpp"
42 #include "prims/jvmtiExport.hpp"
43 #include "runtime/globals.hpp"
44
45 InstanceKlass* vmClasses::_klasses[static_cast<int>(vmClassID::LIMIT)]
46 = { nullptr /*, nullptr...*/ };
47 InstanceKlass* vmClasses::_box_klasses[T_VOID+1] = { nullptr /*, nullptr...*/ };
48
49 bool vmClasses::is_loaded(InstanceKlass* klass) {
50 return klass != nullptr && klass->is_loaded();
51 }
52
53 // Compact table of the vmSymbolIDs of all the VM classes (stored as short to save space)
54 static const short vm_class_name_ids[] = {
55 #define VM_CLASS_NAME(name, symbol) ((short)VM_SYMBOL_ENUM_NAME(symbol)),
56 VM_CLASSES_DO(VM_CLASS_NAME)
57 #undef VM_CLASS_NAME
58 0
59 };
60
61
62 #ifdef ASSERT
63 bool vmClasses::contain(Symbol* class_name) {
64 int sid;
65 for (int i = 0; (sid = vm_class_name_ids[i]) != 0; i++) {
66 Symbol* symbol = vmSymbols::symbol_at(vmSymbols::as_SID(sid));
67 if (class_name == symbol) {
68 return true;
69 }
70 }
71 return false;
72 }
73
74 bool vmClasses::contain(Klass* k) {
75 return contain(k->name());
76 }
77 #endif
78
79 bool vmClasses::resolve(vmClassID id, TRAPS) {
80 InstanceKlass** klassp = &_klasses[as_int(id)];
81
82 #if INCLUDE_CDS
83 if (CDSConfig::is_using_archive() && !JvmtiExport::should_post_class_prepare()) {
84 InstanceKlass* k = *klassp;
85 assert(k->is_shared_boot_class(), "must be");
86
87 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
88 resolve_shared_class(k, loader_data, Handle(), CHECK_false);
89 return true;
90 }
91 #endif // INCLUDE_CDS
92
93 if (!is_loaded(*klassp)) {
94 int sid = vm_class_name_ids[as_int(id)];
95 Symbol* symbol = vmSymbols::symbol_at(vmSymbols::as_SID(sid));
96 Klass* k = SystemDictionary::resolve_or_fail(symbol, true, CHECK_false);
97 (*klassp) = InstanceKlass::cast(k);
98 }
99 return ((*klassp) != nullptr);
100 }
101
102 void vmClasses::resolve_until(vmClassID limit_id, vmClassID &start_id, TRAPS) {
103 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
104 for (auto id : EnumRange<vmClassID>{start_id, limit_id}) { // (inclusive start, exclusive end)
105 resolve(id, CHECK);
106 }
107
108 // move the starting value forward to the limit:
109 start_id = limit_id;
110 }
111
112 void vmClasses::resolve_all(TRAPS) {
113 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
114
115 // Create the ModuleEntry for java.base. This call needs to be done here,
116 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
117 ClassLoader::classLoader_init2(THREAD);
118
119 // Preload commonly used klasses
120 vmClassID scan = vmClassID::FIRST;
121 // first do Object, then String, Class
122 resolve_through(VM_CLASS_ID(Object_klass), scan, CHECK);
123 CollectedHeap::set_filler_object_klass(vmClasses::Object_klass());
124 #if INCLUDE_CDS
125 if (CDSConfig::is_using_archive()) {
126 // It's unsafe to access the archived heap regions before they
127 // are fixed up, so we must do the fixup as early as possible
128 // before the archived java objects are accessed by functions
129 // such as java_lang_Class::restore_archived_mirror and
130 // ConstantPool::restore_unshareable_info (restores the archived
131 // resolved_references array object).
132 //
133 // ArchiveHeapLoader::fixup_regions fills the empty
134 // spaces in the archived heap regions and may use
135 // vmClasses::Object_klass(), so we can do this only after
136 // Object_klass is resolved. See the above resolve_through()
137 // call. No mirror objects are accessed/restored in the above call.
138 // Mirrors are restored after java.lang.Class is loaded.
139 ArchiveHeapLoader::fixup_region();
140
141 // Initialize the constant pool for the Object_class
142 assert(Object_klass()->is_shared(), "must be");
143 Object_klass()->constants()->restore_unshareable_info(CHECK);
144 resolve_through(VM_CLASS_ID(Class_klass), scan, CHECK);
145 } else
146 #endif
147 {
148 resolve_through(VM_CLASS_ID(Class_klass), scan, CHECK);
149 }
150
151 assert(vmClasses::Object_klass() != nullptr, "well-known classes should now be initialized");
152
153 java_lang_Object::register_natives(CHECK);
154
155 // Calculate offsets for String and Class classes since they are loaded and
156 // can be used after this point. These are no-op when CDS is enabled.
157 java_lang_String::compute_offsets();
158 java_lang_Class::compute_offsets();
159
160 // Fixup mirrors for classes loaded before java.lang.Class.
161 Universe::initialize_basic_type_mirrors(CHECK);
162 Universe::fixup_mirrors(CHECK);
163
164 if (CDSConfig::is_using_archive()) {
165 // These should already have been initialized during CDS dump.
166 assert(vmClasses::Reference_klass()->reference_type() == REF_NONE, "sanity");
167 assert(vmClasses::SoftReference_klass()->reference_type() == REF_SOFT, "sanity");
168 assert(vmClasses::WeakReference_klass()->reference_type() == REF_WEAK, "sanity");
169 assert(vmClasses::FinalReference_klass()->reference_type() == REF_FINAL, "sanity");
170 assert(vmClasses::PhantomReference_klass()->reference_type() == REF_PHANTOM, "sanity");
171 } else {
172 // If CDS is not enabled, the references classes must be initialized in
173 // this order before the rest of the vmClasses can be resolved.
174 resolve_through(VM_CLASS_ID(Reference_klass), scan, CHECK);
175
176 // The offsets for jlr.Reference must be computed before
177 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
178 // the offsets to remove the referent and discovered fields from the oop maps,
179 // as they are treated in a special way by the GC. Removing these oops from the
180 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
181 java_lang_ref_Reference::compute_offsets();
182
183 // Preload ref klasses and set reference types
184 InstanceRefKlass::update_nonstatic_oop_maps(vmClasses::Reference_klass());
185
186 resolve_through(VM_CLASS_ID(PhantomReference_klass), scan, CHECK);
187 }
188
189 resolve_until(vmClassID::LIMIT, scan, CHECK);
190
191 CollectedHeap::set_filler_object_klass(vmClasses::FillerObject_klass());
192
193 _box_klasses[T_BOOLEAN] = vmClasses::Boolean_klass();
194 _box_klasses[T_CHAR] = vmClasses::Character_klass();
195 _box_klasses[T_FLOAT] = vmClasses::Float_klass();
196 _box_klasses[T_DOUBLE] = vmClasses::Double_klass();
197 _box_klasses[T_BYTE] = vmClasses::Byte_klass();
198 _box_klasses[T_SHORT] = vmClasses::Short_klass();
199 _box_klasses[T_INT] = vmClasses::Integer_klass();
200 _box_klasses[T_LONG] = vmClasses::Long_klass();
201
202 #ifdef ASSERT
203 if (CDSConfig::is_using_archive()) {
204 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
205 "All well known classes must be resolved in JVMTI early phase"));
206 for (auto id : EnumRange<vmClassID>{}) {
207 InstanceKlass* k = _klasses[as_int(id)];
208 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
209 }
210 }
211 #endif
212
213 InstanceStackChunkKlass::init_offset_of_stack();
214 if (CDSConfig::is_using_aot_linked_classes()) {
215 AOTLinkedClassBulkLoader::load_javabase_boot_classes(THREAD);
216 }
217 }
218
219 #if INCLUDE_CDS
220
221 void vmClasses::resolve_shared_class(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
222 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
223 assert(klass->is_shared(), "Must be shared class");
224 if (klass->class_loader_data() != nullptr) {
225 return;
226 }
227
228 // add super and interfaces first
229 Klass* super = klass->super();
230 if (super != nullptr && super->class_loader_data() == nullptr) {
231 assert(super->is_instance_klass(), "Super should be instance klass");
232 resolve_shared_class(InstanceKlass::cast(super), loader_data, domain, CHECK);
233 }
234
235 Array<InstanceKlass*>* ifs = klass->local_interfaces();
236 for (int i = 0; i < ifs->length(); i++) {
237 InstanceKlass* ik = ifs->at(i);
238 if (ik->class_loader_data() == nullptr) {
239 resolve_shared_class(ik, loader_data, domain, CHECK);
240 }
241 }
242
243 klass->restore_unshareable_info(loader_data, domain, nullptr, THREAD);
244 SystemDictionary::load_shared_class_misc(klass, loader_data);
245 Dictionary* dictionary = loader_data->dictionary();
246 dictionary->add_klass(THREAD, klass->name(), klass);
247 klass->add_to_hierarchy(THREAD);
248 assert(klass->is_loaded(), "Must be in at least loaded state");
249 }
250
251 #endif // INCLUDE_CDS
252
253 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
254 // If so, returns the basic type it holds. If not, returns T_OBJECT.
255 BasicType vmClasses::box_klass_type(Klass* k) {
256 assert(k != nullptr, "");
257 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
258 if (_box_klasses[i] == k)
259 return (BasicType)i;
260 }
261 return T_OBJECT;
262 }