1 /*
2 * Copyright (c) 2018, 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/aotArtifactFinder.hpp"
26 #include "cds/aotClassInitializer.hpp"
27 #include "cds/aotClassLocation.hpp"
28 #include "cds/aotLogging.hpp"
29 #include "cds/aotReferenceObjSupport.hpp"
30 #include "cds/archiveBuilder.hpp"
31 #include "cds/archiveHeapLoader.hpp"
32 #include "cds/archiveHeapWriter.hpp"
33 #include "cds/archiveUtils.hpp"
34 #include "cds/cdsConfig.hpp"
35 #include "cds/cdsEnumKlass.hpp"
36 #include "cds/cdsHeapVerifier.hpp"
37 #include "cds/heapShared.hpp"
38 #include "cds/metaspaceShared.hpp"
39 #include "cds/regeneratedClasses.hpp"
40 #include "classfile/classLoaderData.hpp"
41 #include "classfile/javaClasses.inline.hpp"
42 #include "classfile/modules.hpp"
43 #include "classfile/stringTable.hpp"
44 #include "classfile/symbolTable.hpp"
45 #include "classfile/systemDictionary.hpp"
46 #include "classfile/systemDictionaryShared.hpp"
47 #include "classfile/vmClasses.hpp"
48 #include "classfile/vmSymbols.hpp"
49 #include "gc/shared/collectedHeap.hpp"
50 #include "gc/shared/gcLocker.hpp"
51 #include "gc/shared/gcVMOperations.hpp"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/iterator.inline.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "memory/universe.hpp"
57 #include "oops/compressedOops.inline.hpp"
58 #include "oops/fieldStreams.inline.hpp"
59 #include "oops/objArrayOop.inline.hpp"
60 #include "oops/oop.inline.hpp"
61 #include "oops/typeArrayOop.inline.hpp"
62 #include "prims/jvmtiExport.hpp"
63 #include "runtime/arguments.hpp"
64 #include "runtime/fieldDescriptor.inline.hpp"
65 #include "runtime/init.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/mutexLocker.hpp"
68 #include "runtime/safepointVerifiers.hpp"
69 #include "utilities/bitMap.inline.hpp"
70 #include "utilities/copy.hpp"
71 #if INCLUDE_G1GC
72 #include "gc/g1/g1CollectedHeap.hpp"
73 #endif
74
75 #if INCLUDE_CDS_JAVA_HEAP
76
77 struct ArchivableStaticFieldInfo {
78 const char* klass_name;
79 const char* field_name;
80 InstanceKlass* klass;
81 int offset;
82 BasicType type;
83
84 ArchivableStaticFieldInfo(const char* k, const char* f)
85 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
86
87 bool valid() {
88 return klass_name != nullptr;
89 }
90 };
91
92 DumpedInternedStrings *HeapShared::_dumped_interned_strings = nullptr;
93
94 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
95 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
96 size_t HeapShared::_total_obj_count;
97 size_t HeapShared::_total_obj_size;
98
99 #ifndef PRODUCT
100 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
101 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
102 static const char* _test_class_name = nullptr;
103 static Klass* _test_class = nullptr;
104 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
105 #endif
106
107
108 //
109 // If you add new entries to the following tables, you should know what you're doing!
110 //
111
112 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
113 {"java/lang/Integer$IntegerCache", "archivedCache"},
114 {"java/lang/Long$LongCache", "archivedCache"},
115 {"java/lang/Byte$ByteCache", "archivedCache"},
116 {"java/lang/Short$ShortCache", "archivedCache"},
117 {"java/lang/Character$CharacterCache", "archivedCache"},
118 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
119 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
120 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
121 {"java/util/ImmutableCollections", "archivedObjects"},
122 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
123 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
124 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
125
126 #ifndef PRODUCT
127 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
128 #endif
129 {nullptr, nullptr},
130 };
131
132 // full module graph
133 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
134 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
135 {ARCHIVED_BOOT_LAYER_CLASS, ARCHIVED_BOOT_LAYER_FIELD},
136 {"java/lang/Module$ArchivedData", "archivedData"},
137 {nullptr, nullptr},
138 };
139
140 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
141 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
142 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;
143 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_root_segments = nullptr;
144 int HeapShared::_root_segment_max_size_elems;
145 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
146 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
147
148 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
149 for (int i = 0; fields[i].valid(); i++) {
150 if (fields[i].klass == ik) {
151 return true;
152 }
153 }
154 return false;
155 }
156
157 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
158 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
159 is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
160 }
161
162 unsigned HeapShared::oop_hash(oop const& p) {
163 // Do not call p->identity_hash() as that will update the
164 // object header.
165 return primitive_hash(cast_from_oop<intptr_t>(p));
166 }
167
168 static void reset_states(oop obj, TRAPS) {
169 Handle h_obj(THREAD, obj);
170 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
171 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
172 Symbol* method_sig = vmSymbols::void_method_signature();
173
174 while (klass != nullptr) {
175 Method* method = klass->find_method(method_name, method_sig);
176 if (method != nullptr) {
177 assert(method->is_private(), "must be");
178 if (log_is_enabled(Debug, aot)) {
179 ResourceMark rm(THREAD);
180 log_debug(aot)(" calling %s", method->name_and_sig_as_C_string());
181 }
182 JavaValue result(T_VOID);
183 JavaCalls::call_special(&result, h_obj, klass,
184 method_name, method_sig, CHECK);
185 }
186 klass = klass->java_super();
187 }
188 }
189
190 void HeapShared::reset_archived_object_states(TRAPS) {
191 assert(CDSConfig::is_dumping_heap(), "dump-time only");
192 log_debug(aot)("Resetting platform loader");
193 reset_states(SystemDictionary::java_platform_loader(), CHECK);
194 log_debug(aot)("Resetting system loader");
195 reset_states(SystemDictionary::java_system_loader(), CHECK);
196
197 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
198 // directly used for class loading, but rather is used by the core library
199 // to keep track of resources, etc, loaded by the null class loader.
200 //
201 // Note, this object is non-null, and is not the same as
202 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
203 // which is null.
204 log_debug(aot)("Resetting boot loader");
205 JavaValue result(T_OBJECT);
206 JavaCalls::call_static(&result,
207 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
208 vmSymbols::bootLoader_name(),
209 vmSymbols::void_BuiltinClassLoader_signature(),
210 CHECK);
211 Handle boot_loader(THREAD, result.get_oop());
212 reset_states(boot_loader(), CHECK);
213 }
214
215 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
216
217 bool HeapShared::has_been_archived(oop obj) {
218 assert(CDSConfig::is_dumping_heap(), "dump-time only");
219 return archived_object_cache()->get(obj) != nullptr;
220 }
221
222 int HeapShared::append_root(oop obj) {
223 assert(CDSConfig::is_dumping_heap(), "dump-time only");
224 if (obj != nullptr) {
225 assert(has_been_archived(obj), "must be");
226 }
227 // No GC should happen since we aren't scanning _pending_roots.
228 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
229
230 return _pending_roots->append(obj);
231 }
232
233 objArrayOop HeapShared::root_segment(int segment_idx) {
234 if (CDSConfig::is_dumping_heap()) {
235 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
236 } else {
237 assert(CDSConfig::is_using_archive(), "must be");
238 }
239
240 objArrayOop segment = (objArrayOop)_root_segments->at(segment_idx).resolve();
241 assert(segment != nullptr, "should have been initialized");
242 return segment;
243 }
244
245 void HeapShared::get_segment_indexes(int idx, int& seg_idx, int& int_idx) {
246 assert(_root_segment_max_size_elems > 0, "sanity");
247
248 // Try to avoid divisions for the common case.
249 if (idx < _root_segment_max_size_elems) {
250 seg_idx = 0;
251 int_idx = idx;
252 } else {
253 seg_idx = idx / _root_segment_max_size_elems;
254 int_idx = idx % _root_segment_max_size_elems;
255 }
256
257 assert(idx == seg_idx * _root_segment_max_size_elems + int_idx,
258 "sanity: %d index maps to %d segment and %d internal", idx, seg_idx, int_idx);
259 }
260
261 // Returns an objArray that contains all the roots of the archived objects
262 oop HeapShared::get_root(int index, bool clear) {
263 assert(index >= 0, "sanity");
264 assert(!CDSConfig::is_dumping_heap() && CDSConfig::is_using_archive(), "runtime only");
265 assert(!_root_segments->is_empty(), "must have loaded shared heap");
266 int seg_idx, int_idx;
267 get_segment_indexes(index, seg_idx, int_idx);
268 oop result = root_segment(seg_idx)->obj_at(int_idx);
269 if (clear) {
270 clear_root(index);
271 }
272 return result;
273 }
274
275 void HeapShared::clear_root(int index) {
276 assert(index >= 0, "sanity");
277 assert(CDSConfig::is_using_archive(), "must be");
278 if (ArchiveHeapLoader::is_in_use()) {
279 int seg_idx, int_idx;
280 get_segment_indexes(index, seg_idx, int_idx);
281 if (log_is_enabled(Debug, aot, heap)) {
282 oop old = root_segment(seg_idx)->obj_at(int_idx);
283 log_debug(aot, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
284 }
285 root_segment(seg_idx)->obj_at_put(int_idx, nullptr);
286 }
287 }
288
289 bool HeapShared::archive_object(oop obj, oop referrer, KlassSubGraphInfo* subgraph_info) {
290 assert(CDSConfig::is_dumping_heap(), "dump-time only");
291
292 assert(!obj->is_stackChunk(), "do not archive stack chunks");
293 if (has_been_archived(obj)) {
294 return true;
295 }
296
297 if (ArchiveHeapWriter::is_too_large_to_archive(obj->size())) {
298 log_debug(aot, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: %zu",
299 p2i(obj), obj->size());
300 debug_trace();
301 return false;
302 } else {
303 count_allocation(obj->size());
304 ArchiveHeapWriter::add_source_obj(obj);
305 CachedOopInfo info = make_cached_oop_info(obj, referrer);
306 archived_object_cache()->put_when_absent(obj, info);
307 archived_object_cache()->maybe_grow();
308 mark_native_pointers(obj);
309
310 Klass* k = obj->klass();
311 if (k->is_instance_klass()) {
312 // Whenever we see a non-array Java object of type X, we mark X to be aot-initialized.
313 // This ensures that during the production run, whenever Java code sees a cached object
314 // of type X, we know that X is already initialized. (see TODO comment below ...)
315
316 if (InstanceKlass::cast(k)->is_enum_subclass()
317 // We can't rerun <clinit> of enum classes (see cdsEnumKlass.cpp) so
318 // we must store them as AOT-initialized.
319 || (subgraph_info == _dump_time_special_subgraph))
320 // TODO: we do this only for the special subgraph for now. Extending this to
321 // other subgraphs would require more refactoring of the core library (such as
322 // move some initialization logic into runtimeSetup()).
323 //
324 // For the other subgraphs, we have a weaker mechanism to ensure that
325 // all classes in a subgraph are initialized before the subgraph is programmatically
326 // returned from jdk.internal.misc.CDS::initializeFromArchive().
327 // See HeapShared::initialize_from_archived_subgraph().
328 {
329 AOTArtifactFinder::add_aot_inited_class(InstanceKlass::cast(k));
330 }
331
332 if (java_lang_Class::is_instance(obj)) {
333 Klass* mirror_k = java_lang_Class::as_Klass(obj);
334 if (mirror_k != nullptr) {
335 AOTArtifactFinder::add_cached_class(mirror_k);
336 }
337 } else if (java_lang_invoke_ResolvedMethodName::is_instance(obj)) {
338 Method* m = java_lang_invoke_ResolvedMethodName::vmtarget(obj);
339 if (m != nullptr) {
340 if (RegeneratedClasses::has_been_regenerated(m)) {
341 m = RegeneratedClasses::get_regenerated_object(m);
342 }
343 InstanceKlass* method_holder = m->method_holder();
344 AOTArtifactFinder::add_cached_class(method_holder);
345 }
346 }
347 }
348
349 if (log_is_enabled(Debug, aot, heap)) {
350 ResourceMark rm;
351 LogTarget(Debug, aot, heap) log;
352 LogStream out(log);
353 out.print("Archived heap object " PTR_FORMAT " : %s ",
354 p2i(obj), obj->klass()->external_name());
355 if (java_lang_Class::is_instance(obj)) {
356 Klass* k = java_lang_Class::as_Klass(obj);
357 if (k != nullptr) {
358 out.print("%s", k->external_name());
359 } else {
360 out.print("primitive");
361 }
362 }
363 out.cr();
364 }
365
366 return true;
367 }
368 }
369
370 class MetaspaceObjToOopHandleTable: public ResourceHashtable<MetaspaceObj*, OopHandle,
371 36137, // prime number
372 AnyObj::C_HEAP,
373 mtClassShared> {
374 public:
375 oop get_oop(MetaspaceObj* ptr) {
376 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
377 OopHandle* handle = get(ptr);
378 if (handle != nullptr) {
379 return handle->resolve();
380 } else {
381 return nullptr;
382 }
383 }
384 void set_oop(MetaspaceObj* ptr, oop o) {
385 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
386 OopHandle handle(Universe::vm_global(), o);
387 bool is_new = put(ptr, handle);
388 assert(is_new, "cannot set twice");
389 }
390 void remove_oop(MetaspaceObj* ptr) {
391 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
392 OopHandle* handle = get(ptr);
393 if (handle != nullptr) {
394 handle->release(Universe::vm_global());
395 remove(ptr);
396 }
397 }
398 };
399
400 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
401 if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
402 _scratch_objects_table->set_oop(src, dest);
403 }
404 }
405
406 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
407 return (objArrayOop)_scratch_objects_table->get_oop(src);
408 }
409
410 void HeapShared::init_dumping() {
411 _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
412 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
413 }
414
415 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
416 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
417 BasicType bt = (BasicType)i;
418 if (!is_reference_type(bt)) {
419 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
420 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
421 }
422 }
423 }
424
425 // Given java_mirror that represents a (primitive or reference) type T,
426 // return the "scratch" version that represents the same type T.
427 // Note that if java_mirror will be returned if it's already a
428 // scratch mirror.
429 //
430 // See java_lang_Class::create_scratch_mirror() for more info.
431 oop HeapShared::scratch_java_mirror(oop java_mirror) {
432 assert(java_lang_Class::is_instance(java_mirror), "must be");
433
434 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
435 BasicType bt = (BasicType)i;
436 if (!is_reference_type(bt)) {
437 if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
438 return java_mirror;
439 }
440 }
441 }
442
443 if (java_lang_Class::is_primitive(java_mirror)) {
444 return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
445 } else {
446 return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
447 }
448 }
449
450 oop HeapShared::scratch_java_mirror(BasicType t) {
451 assert((uint)t < T_VOID+1, "range check");
452 assert(!is_reference_type(t), "sanity");
453 return _scratch_basic_type_mirrors[t].resolve();
454 }
455
456 oop HeapShared::scratch_java_mirror(Klass* k) {
457 return _scratch_objects_table->get_oop(k);
458 }
459
460 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
461 _scratch_objects_table->set_oop(k, mirror);
462 }
463
464 void HeapShared::remove_scratch_objects(Klass* k) {
465 // Klass is being deallocated. Java mirror can still be alive, and it should not
466 // point to dead klass. We need to break the link from mirror to the Klass.
467 // See how InstanceKlass::deallocate_contents does it for normal mirrors.
468 oop mirror = _scratch_objects_table->get_oop(k);
469 if (mirror != nullptr) {
470 java_lang_Class::set_klass(mirror, nullptr);
471 }
472 _scratch_objects_table->remove_oop(k);
473 if (k->is_instance_klass()) {
474 _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
475 }
476 }
477
478 //TODO: we eventually want a more direct test for these kinds of things.
479 //For example the JVM could record some bit of context from the creation
480 //of the klass, such as who called the hidden class factory. Using
481 //string compares on names is fragile and will break as soon as somebody
482 //changes the names in the JDK code. See discussion in JDK-8342481 for
483 //related ideas about marking AOT-related classes.
484 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
485 return ik->is_hidden() &&
486 (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
487 ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
488 ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
489 ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
490 }
491
492 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
493 return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
494 }
495
496 bool HeapShared::is_string_concat_klass(InstanceKlass* ik) {
497 return ik->is_hidden() && ik->name()->starts_with("java/lang/String$$StringConcat");
498 }
499
500 bool HeapShared::is_archivable_hidden_klass(InstanceKlass* ik) {
501 return CDSConfig::is_dumping_method_handles() &&
502 (is_lambda_form_klass(ik) || is_lambda_proxy_klass(ik) || is_string_concat_klass(ik));
503 }
504
505
506 void HeapShared::copy_and_rescan_aot_inited_mirror(InstanceKlass* ik) {
507 ik->set_has_aot_initialized_mirror();
508 if (AOTClassInitializer::is_runtime_setup_required(ik)) {
509 ik->set_is_runtime_setup_required();
510 }
511
512 oop orig_mirror;
513 if (RegeneratedClasses::is_regenerated_object(ik)) {
514 InstanceKlass* orig_ik = RegeneratedClasses::get_original_object(ik);
515 precond(orig_ik->is_initialized());
516 orig_mirror = orig_ik->java_mirror();
517 } else {
518 precond(ik->is_initialized());
519 orig_mirror = ik->java_mirror();
520 }
521
522 oop m = scratch_java_mirror(ik);
523 int nfields = 0;
524 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
525 if (fs.access_flags().is_static()) {
526 fieldDescriptor& fd = fs.field_descriptor();
527 int offset = fd.offset();
528 switch (fd.field_type()) {
529 case T_OBJECT:
530 case T_ARRAY:
531 {
532 oop field_obj = orig_mirror->obj_field(offset);
533 if (offset == java_lang_Class::reflection_data_offset()) {
534 // Class::reflectData use SoftReference, which cannot be archived. Set it
535 // to null and it will be recreated at runtime.
536 field_obj = nullptr;
537 }
538 m->obj_field_put(offset, field_obj);
539 if (field_obj != nullptr) {
540 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
541 assert(success, "sanity");
542 }
543 }
544 break;
545 case T_BOOLEAN:
546 m->bool_field_put(offset, orig_mirror->bool_field(offset));
547 break;
548 case T_BYTE:
549 m->byte_field_put(offset, orig_mirror->byte_field(offset));
550 break;
551 case T_SHORT:
552 m->short_field_put(offset, orig_mirror->short_field(offset));
553 break;
554 case T_CHAR:
555 m->char_field_put(offset, orig_mirror->char_field(offset));
556 break;
557 case T_INT:
558 m->int_field_put(offset, orig_mirror->int_field(offset));
559 break;
560 case T_LONG:
561 m->long_field_put(offset, orig_mirror->long_field(offset));
562 break;
563 case T_FLOAT:
564 m->float_field_put(offset, orig_mirror->float_field(offset));
565 break;
566 case T_DOUBLE:
567 m->double_field_put(offset, orig_mirror->double_field(offset));
568 break;
569 default:
570 ShouldNotReachHere();
571 }
572 nfields ++;
573 }
574 }
575
576 oop class_data = java_lang_Class::class_data(orig_mirror);
577 java_lang_Class::set_class_data(m, class_data);
578 if (class_data != nullptr) {
579 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
580 assert(success, "sanity");
581 }
582
583 if (log_is_enabled(Debug, aot, init)) {
584 ResourceMark rm;
585 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
586 ik->is_hidden() ? " (hidden)" : "",
587 ik->is_enum_subclass() ? " (enum)" : "");
588 }
589 }
590
591 static void copy_java_mirror_hashcode(oop orig_mirror, oop scratch_m) {
592 // We need to retain the identity_hash, because it may have been used by some hashtables
593 // in the shared heap.
594 if (!orig_mirror->fast_no_hash_check()) {
595 intptr_t src_hash = orig_mirror->identity_hash();
596 if (UseCompactObjectHeaders) {
597 narrowKlass nk = CompressedKlassPointers::encode(orig_mirror->klass());
598 scratch_m->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
599 } else {
600 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
601 }
602 assert(scratch_m->mark().is_unlocked(), "sanity");
603
604 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
605 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
606 }
607 }
608
609 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
610 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
611 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
612 if (rr != nullptr && !ArchiveHeapWriter::is_too_large_to_archive(rr)) {
613 return HeapShared::scratch_resolved_references(src_ik->constants());
614 }
615 }
616 return nullptr;
617 }
618
619 void HeapShared::archive_strings() {
620 oop shared_strings_array = StringTable::init_shared_strings_array();
621 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, shared_strings_array);
622 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
623 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
624 }
625
626 int HeapShared::archive_exception_instance(oop exception) {
627 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
628 assert(success, "sanity");
629 return append_root(exception);
630 }
631
632 void HeapShared::mark_native_pointers(oop orig_obj) {
633 if (java_lang_Class::is_instance(orig_obj)) {
634 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::klass_offset());
635 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::array_klass_offset());
636 } else if (java_lang_invoke_ResolvedMethodName::is_instance(orig_obj)) {
637 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_invoke_ResolvedMethodName::vmtarget_offset());
638 }
639 }
640
641 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
642 CachedOopInfo* info = archived_object_cache()->get(src_obj);
643 assert(info != nullptr, "must be");
644 has_oop_pointers = info->has_oop_pointers();
645 has_native_pointers = info->has_native_pointers();
646 }
647
648 void HeapShared::set_has_native_pointers(oop src_obj) {
649 CachedOopInfo* info = archived_object_cache()->get(src_obj);
650 assert(info != nullptr, "must be");
651 info->set_has_native_pointers();
652 }
653
654 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
655 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
656 void HeapShared::start_scanning_for_oops() {
657 {
658 NoSafepointVerifier nsv;
659
660 // The special subgraph doesn't belong to any class. We use Object_klass() here just
661 // for convenience.
662 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
663
664 // Cache for recording where the archived objects are copied to
665 create_archived_object_cache();
666
667 if (UseCompressedOops || UseG1GC) {
668 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
669 UseCompressedOops ? p2i(CompressedOops::begin()) :
670 p2i((address)G1CollectedHeap::heap()->reserved().start()),
671 UseCompressedOops ? p2i(CompressedOops::end()) :
672 p2i((address)G1CollectedHeap::heap()->reserved().end()));
673 }
674
675 archive_subgraphs();
676 }
677
678 init_seen_objects_table();
679 Universe::archive_exception_instances();
680 }
681
682 void HeapShared::end_scanning_for_oops() {
683 archive_strings();
684 delete_seen_objects_table();
685 }
686
687 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
688 {
689 NoSafepointVerifier nsv;
690 CDSHeapVerifier::verify();
691 check_special_subgraph_classes();
692 }
693
694 StringTable::write_shared_table();
695 ArchiveHeapWriter::write(_pending_roots, heap_info);
696
697 ArchiveBuilder::OtherROAllocMark mark;
698 write_subgraph_info_table();
699 }
700
701 void HeapShared::scan_java_mirror(oop orig_mirror) {
702 oop m = scratch_java_mirror(orig_mirror);
703 if (m != nullptr) { // nullptr if for custom class loader
704 copy_java_mirror_hashcode(orig_mirror, m);
705 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
706 assert(success, "sanity");
707 }
708 }
709
710 void HeapShared::scan_java_class(Klass* orig_k) {
711 scan_java_mirror(orig_k->java_mirror());
712
713 if (orig_k->is_instance_klass()) {
714 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
715 orig_ik->constants()->prepare_resolved_references_for_archiving();
716 objArrayOop rr = get_archived_resolved_references(orig_ik);
717 if (rr != nullptr) {
718 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
719 assert(success, "must be");
720 }
721 }
722 }
723
724 void HeapShared::archive_subgraphs() {
725 assert(CDSConfig::is_dumping_heap(), "must be");
726
727 archive_object_subgraphs(archive_subgraph_entry_fields,
728 false /* is_full_module_graph */);
729
730 if (CDSConfig::is_dumping_full_module_graph()) {
731 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
732 true /* is_full_module_graph */);
733 Modules::verify_archived_modules();
734 }
735 }
736
737 //
738 // Subgraph archiving support
739 //
740 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
741 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
742
743 // Get the subgraph_info for Klass k. A new subgraph_info is created if
744 // there is no existing one for k. The subgraph_info records the "buffered"
745 // address of the class.
746 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
747 assert(CDSConfig::is_dumping_heap(), "dump time only");
748 bool created;
749 KlassSubGraphInfo* info =
750 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
751 &created);
752 assert(created, "must not initialize twice");
753 return info;
754 }
755
756 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
757 assert(CDSConfig::is_dumping_heap(), "dump time only");
758 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
759 assert(info != nullptr, "must have been initialized");
760 return info;
761 }
762
763 // Add an entry field to the current KlassSubGraphInfo.
764 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
765 assert(CDSConfig::is_dumping_heap(), "dump time only");
766 if (_subgraph_entry_fields == nullptr) {
767 _subgraph_entry_fields =
768 new (mtClass) GrowableArray<int>(10, mtClass);
769 }
770 _subgraph_entry_fields->append(static_field_offset);
771 _subgraph_entry_fields->append(HeapShared::append_root(v));
772 }
773
774 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
775 // Only objects of boot classes can be included in sub-graph.
776 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
777 assert(CDSConfig::is_dumping_heap(), "dump time only");
778
779 if (_subgraph_object_klasses == nullptr) {
780 _subgraph_object_klasses =
781 new (mtClass) GrowableArray<Klass*>(50, mtClass);
782 }
783
784 if (_k == orig_k) {
785 // Don't add the Klass containing the sub-graph to it's own klass
786 // initialization list.
787 return;
788 }
789
790 if (orig_k->is_instance_klass()) {
791 #ifdef ASSERT
792 InstanceKlass* ik = InstanceKlass::cast(orig_k);
793 if (CDSConfig::is_dumping_method_handles()) {
794 // -XX:AOTInitTestClass must be used carefully in regression tests to
795 // include only classes that are safe to aot-initialize.
796 assert(ik->class_loader() == nullptr ||
797 HeapShared::is_lambda_proxy_klass(ik) ||
798 AOTClassInitializer::has_test_class(),
799 "we can archive only instances of boot classes or lambda proxy classes");
800 } else {
801 assert(ik->class_loader() == nullptr, "must be boot class");
802 }
803 #endif
804 // vmClasses::xxx_klass() are not updated, need to check
805 // the original Klass*
806 if (orig_k == vmClasses::String_klass() ||
807 orig_k == vmClasses::Object_klass()) {
808 // Initialized early during VM initialization. No need to be added
809 // to the sub-graph object class list.
810 return;
811 }
812 check_allowed_klass(InstanceKlass::cast(orig_k));
813 } else if (orig_k->is_objArray_klass()) {
814 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
815 if (abk->is_instance_klass()) {
816 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
817 "must be boot class");
818 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
819 }
820 if (orig_k == Universe::objectArrayKlass()) {
821 // Initialized early during Universe::genesis. No need to be added
822 // to the list.
823 return;
824 }
825 } else {
826 assert(orig_k->is_typeArray_klass(), "must be");
827 // Primitive type arrays are created early during Universe::genesis.
828 return;
829 }
830
831 if (log_is_enabled(Debug, aot, heap)) {
832 if (!_subgraph_object_klasses->contains(orig_k)) {
833 ResourceMark rm;
834 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
835 }
836 }
837
838 _subgraph_object_klasses->append_if_missing(orig_k);
839 _has_non_early_klasses |= is_non_early_klass(orig_k);
840 }
841
842 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
843 #ifndef PRODUCT
844 if (AOTClassInitializer::has_test_class()) {
845 // The tests can cache arbitrary types of objects.
846 return;
847 }
848 #endif
849
850 if (ik->module()->name() == vmSymbols::java_base()) {
851 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
852 return;
853 }
854
855 const char* lambda_msg = "";
856 if (CDSConfig::is_dumping_method_handles()) {
857 lambda_msg = ", or a lambda proxy class";
858 if (HeapShared::is_lambda_proxy_klass(ik) &&
859 (ik->class_loader() == nullptr ||
860 ik->class_loader() == SystemDictionary::java_platform_loader() ||
861 ik->class_loader() == SystemDictionary::java_system_loader())) {
862 return;
863 }
864 }
865
866 #ifndef PRODUCT
867 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
868 // This class is loaded by ArchiveHeapTestClass
869 return;
870 }
871 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
872 #else
873 const char* testcls_msg = "";
874 #endif
875
876 ResourceMark rm;
877 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
878 ik->external_name(), lambda_msg, testcls_msg);
879 MetaspaceShared::unrecoverable_writing_error();
880 }
881
882 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
883 if (k->is_objArray_klass()) {
884 k = ObjArrayKlass::cast(k)->bottom_klass();
885 }
886 if (k->is_instance_klass()) {
887 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
888 ResourceMark rm;
889 log_info(aot, heap)("non-early: %s", k->external_name());
890 return true;
891 } else {
892 return false;
893 }
894 } else {
895 return false;
896 }
897 }
898
899 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
900 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
901 _k = ArchiveBuilder::get_buffered_klass(info->klass());
902 _entry_field_records = nullptr;
903 _subgraph_object_klasses = nullptr;
904 _is_full_module_graph = info->is_full_module_graph();
905
906 if (_is_full_module_graph) {
907 // Consider all classes referenced by the full module graph as early -- we will be
908 // allocating objects of these classes during JVMTI early phase, so they cannot
909 // be processed by (non-early) JVMTI ClassFileLoadHook
910 _has_non_early_klasses = false;
911 } else {
912 _has_non_early_klasses = info->has_non_early_klasses();
913 }
914
915 if (_has_non_early_klasses) {
916 ResourceMark rm;
917 log_info(aot, heap)(
918 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
919 _k->external_name());
920 }
921
922 // populate the entry fields
923 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
924 if (entry_fields != nullptr) {
925 int num_entry_fields = entry_fields->length();
926 assert(num_entry_fields % 2 == 0, "sanity");
927 _entry_field_records =
928 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
929 for (int i = 0 ; i < num_entry_fields; i++) {
930 _entry_field_records->at_put(i, entry_fields->at(i));
931 }
932 }
933
934 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
935 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
936 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
937 if (recorded_klasses != nullptr) {
938 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
939 // programmatically loading a subgraph, we only need to explicitly initialize the classes
940 // that are not aot-inited.
941 int num_to_copy = 0;
942 for (int i = 0; i < recorded_klasses->length(); i++) {
943 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
944 if (!subgraph_k->has_aot_initialized_mirror()) {
945 num_to_copy ++;
946 }
947 }
948
949 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
950 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
951 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
952 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
953 if (subgraph_k->has_aot_initialized_mirror()) {
954 continue;
955 }
956 if (log_is_enabled(Info, aot, heap)) {
957 ResourceMark rm;
958 const char* owner_name = is_special ? "<special>" : _k->external_name();
959 if (subgraph_k->is_instance_klass()) {
960 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
961 }
962 log_info(aot, heap)(
963 "Archived object klass %s (%2d) => %s",
964 owner_name, n, subgraph_k->external_name());
965 }
966 _subgraph_object_klasses->at_put(n, subgraph_k);
967 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
968 n++;
969 }
970 }
971
972 ArchivePtrMarker::mark_pointer(&_k);
973 ArchivePtrMarker::mark_pointer(&_entry_field_records);
974 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
975 }
976
977 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
978 CompactHashtableWriter* _writer;
979 public:
980 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
981
982 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
983 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
984 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
985 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
986 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
987 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
988 _writer->add(hash, delta);
989 }
990 return true; // keep on iterating
991 }
992 };
993
994 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
995 ArchivedKlassSubGraphInfoRecord* record =
996 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
997 record->init(info);
998 if (info == _dump_time_special_subgraph) {
999 _run_time_special_subgraph = record;
1000 }
1001 return record;
1002 }
1003
1004 // Build the records of archived subgraph infos, which include:
1005 // - Entry points to all subgraphs from the containing class mirror. The entry
1006 // points are static fields in the mirror. For each entry point, the field
1007 // offset, and value are recorded in the sub-graph
1008 // info. The value is stored back to the corresponding field at runtime.
1009 // - A list of klasses that need to be loaded/initialized before archived
1010 // java object sub-graph can be accessed at runtime.
1011 void HeapShared::write_subgraph_info_table() {
1012 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1013 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1014 CompactHashtableStats stats;
1015
1016 _run_time_subgraph_info_table.reset();
1017
1018 CompactHashtableWriter writer(d_table->_count, &stats);
1019 CopyKlassSubGraphInfoToArchive copy(&writer);
1020 d_table->iterate(©);
1021 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1022
1023 #ifndef PRODUCT
1024 if (ArchiveHeapTestClass != nullptr) {
1025 size_t len = strlen(ArchiveHeapTestClass) + 1;
1026 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1027 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1028 _archived_ArchiveHeapTestClass = array;
1029 }
1030 #endif
1031 if (log_is_enabled(Info, aot, heap)) {
1032 print_stats();
1033 }
1034 }
1035
1036 void HeapShared::add_root_segment(objArrayOop segment_oop) {
1037 assert(segment_oop != nullptr, "must be");
1038 assert(ArchiveHeapLoader::is_in_use(), "must be");
1039 if (_root_segments == nullptr) {
1040 _root_segments = new GrowableArrayCHeap<OopHandle, mtClassShared>(10);
1041 }
1042 _root_segments->push(OopHandle(Universe::vm_global(), segment_oop));
1043 }
1044
1045 void HeapShared::init_root_segment_sizes(int max_size_elems) {
1046 _root_segment_max_size_elems = max_size_elems;
1047 }
1048
1049 void HeapShared::serialize_tables(SerializeClosure* soc) {
1050
1051 #ifndef PRODUCT
1052 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1053 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1054 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1055 setup_test_class(_test_class_name);
1056 }
1057 #endif
1058
1059 _run_time_subgraph_info_table.serialize_header(soc);
1060 soc->do_ptr(&_run_time_special_subgraph);
1061 }
1062
1063 static void verify_the_heap(Klass* k, const char* which) {
1064 if (VerifyArchivedFields > 0) {
1065 ResourceMark rm;
1066 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1067 which, k->external_name());
1068
1069 VM_Verify verify_op;
1070 VMThread::execute(&verify_op);
1071
1072 if (VerifyArchivedFields > 1 && is_init_completed()) {
1073 // At this time, the oop->klass() of some archived objects in the heap may not
1074 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1075 // have enough information (object size, oop maps, etc) so that a GC can be safely
1076 // performed.
1077 //
1078 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1079 // to check for GC safety.
1080 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1081 which, k->external_name());
1082 FlagSetting fs1(VerifyBeforeGC, true);
1083 FlagSetting fs2(VerifyDuringGC, true);
1084 FlagSetting fs3(VerifyAfterGC, true);
1085 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1086 }
1087 }
1088 }
1089
1090 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1091 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1092 //
1093 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1094 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1095 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1096 void HeapShared::resolve_classes(JavaThread* current) {
1097 assert(CDSConfig::is_using_archive(), "runtime only!");
1098 if (!ArchiveHeapLoader::is_in_use()) {
1099 return; // nothing to do
1100 }
1101 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1102 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1103 }
1104
1105 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1106 for (int i = 0; fields[i].valid(); i++) {
1107 ArchivableStaticFieldInfo* info = &fields[i];
1108 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1109 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1110 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1111 resolve_classes_for_subgraph_of(current, k);
1112 }
1113 }
1114
1115 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1116 JavaThread* THREAD = current;
1117 ExceptionMark em(THREAD);
1118 const ArchivedKlassSubGraphInfoRecord* record =
1119 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1120 if (HAS_PENDING_EXCEPTION) {
1121 CLEAR_PENDING_EXCEPTION;
1122 }
1123 if (record == nullptr) {
1124 clear_archived_roots_of(k);
1125 }
1126 }
1127
1128 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1129 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1130 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1131 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1132 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1133 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1134 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1135 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1136 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1137 }
1138 }
1139
1140 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1141 // - interned strings
1142 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1143 // - ConstantPool::resolved_references()
1144 // - Universe::<xxx>_exception_instance()
1145 //
1146 // For example, if this enum class is initialized at AOT cache assembly time:
1147 //
1148 // enum Fruit {
1149 // APPLE, ORANGE, BANANA;
1150 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1151 // }
1152 //
1153 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1154 // should be initialized before any Java code can access the Fruit class. Note that
1155 // HashSet itself doesn't necessary need to be an aot-initialized class.
1156 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1157 if (!ArchiveHeapLoader::is_in_use()) {
1158 return;
1159 }
1160
1161 assert( _run_time_special_subgraph != nullptr, "must be");
1162 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1163 if (klasses != nullptr) {
1164 for (int pass = 0; pass < 2; pass ++) {
1165 for (int i = 0; i < klasses->length(); i++) {
1166 Klass* k = klasses->at(i);
1167 if (k->class_loader_data() == nullptr) {
1168 // This class is not yet loaded. We will initialize it in a later phase.
1169 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1170 // but k is part of AOTLinkedClassCategory::BOOT2.
1171 continue;
1172 }
1173 if (k->class_loader() == class_loader()) {
1174 if (pass == 0) {
1175 if (k->is_instance_klass()) {
1176 InstanceKlass::cast(k)->link_class(CHECK);
1177 }
1178 } else {
1179 resolve_or_init(k, /*do_init*/true, CHECK);
1180 }
1181 }
1182 }
1183 }
1184 }
1185 }
1186
1187 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1188 JavaThread* THREAD = current;
1189 if (!ArchiveHeapLoader::is_in_use()) {
1190 return; // nothing to do
1191 }
1192
1193 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1194 !CDSConfig::is_using_optimized_module_handling() &&
1195 // archive was created with --module-path
1196 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1197 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1198 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1199 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1200 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1201 AOTClassLocationConfig::runtime()->num_module_paths());
1202 return;
1203 }
1204
1205 ExceptionMark em(THREAD);
1206 const ArchivedKlassSubGraphInfoRecord* record =
1207 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1208
1209 if (HAS_PENDING_EXCEPTION) {
1210 CLEAR_PENDING_EXCEPTION;
1211 // None of the field value will be set if there was an exception when initializing the classes.
1212 // The java code will not see any of the archived objects in the
1213 // subgraphs referenced from k in this case.
1214 return;
1215 }
1216
1217 if (record != nullptr) {
1218 init_archived_fields_for(k, record);
1219 }
1220 }
1221
1222 const ArchivedKlassSubGraphInfoRecord*
1223 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1224 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1225
1226 if (!k->is_shared()) {
1227 return nullptr;
1228 }
1229 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1230 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1231
1232 #ifndef PRODUCT
1233 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1234 _test_class = k;
1235 _test_class_record = record;
1236 }
1237 #endif
1238
1239 // Initialize from archived data. Currently this is done only
1240 // during VM initialization time. No lock is needed.
1241 if (record == nullptr) {
1242 if (log_is_enabled(Info, aot, heap)) {
1243 ResourceMark rm(THREAD);
1244 log_info(aot, heap)("subgraph %s is not recorded",
1245 k->external_name());
1246 }
1247 return nullptr;
1248 } else {
1249 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1250 if (log_is_enabled(Info, aot, heap)) {
1251 ResourceMark rm(THREAD);
1252 log_info(aot, heap)("subgraph %s cannot be used because full module graph is disabled",
1253 k->external_name());
1254 }
1255 return nullptr;
1256 }
1257
1258 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1259 if (log_is_enabled(Info, aot, heap)) {
1260 ResourceMark rm(THREAD);
1261 log_info(aot, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1262 k->external_name());
1263 }
1264 return nullptr;
1265 }
1266
1267 if (log_is_enabled(Info, aot, heap)) {
1268 ResourceMark rm;
1269 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1270 }
1271
1272 resolve_or_init(k, do_init, CHECK_NULL);
1273
1274 // Load/link/initialize the klasses of the objects in the subgraph.
1275 // nullptr class loader is used.
1276 Array<Klass*>* klasses = record->subgraph_object_klasses();
1277 if (klasses != nullptr) {
1278 for (int i = 0; i < klasses->length(); i++) {
1279 Klass* klass = klasses->at(i);
1280 if (!klass->is_shared()) {
1281 return nullptr;
1282 }
1283 resolve_or_init(klass, do_init, CHECK_NULL);
1284 }
1285 }
1286 }
1287
1288 return record;
1289 }
1290
1291 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1292 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1293 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1294 if (k == nullptr) {
1295 return;
1296 }
1297 assert(k->defined_by_boot_loader(), "sanity");
1298 resolve_or_init(k, false, CHECK);
1299 if (do_init) {
1300 resolve_or_init(k, true, CHECK);
1301 }
1302 }
1303
1304 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1305 if (!do_init) {
1306 if (k->class_loader_data() == nullptr) {
1307 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1308 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1309 }
1310 } else {
1311 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1312 if (k->is_instance_klass()) {
1313 InstanceKlass* ik = InstanceKlass::cast(k);
1314 ik->initialize(CHECK);
1315 } else if (k->is_objArray_klass()) {
1316 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1317 oak->initialize(CHECK);
1318 }
1319 }
1320 }
1321
1322 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1323 verify_the_heap(k, "before");
1324
1325 // Load the subgraph entry fields from the record and store them back to
1326 // the corresponding fields within the mirror.
1327 oop m = k->java_mirror();
1328 Array<int>* entry_field_records = record->entry_field_records();
1329 if (entry_field_records != nullptr) {
1330 int efr_len = entry_field_records->length();
1331 assert(efr_len % 2 == 0, "sanity");
1332 for (int i = 0; i < efr_len; i += 2) {
1333 int field_offset = entry_field_records->at(i);
1334 int root_index = entry_field_records->at(i+1);
1335 oop v = get_root(root_index, /*clear=*/true);
1336 if (k->has_aot_initialized_mirror()) {
1337 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1338 } else {
1339 m->obj_field_put(field_offset, v);
1340 }
1341 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1342 }
1343
1344 // Done. Java code can see the archived sub-graphs referenced from k's
1345 // mirror after this point.
1346 if (log_is_enabled(Info, aot, heap)) {
1347 ResourceMark rm;
1348 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1349 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1350 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1351 }
1352 }
1353
1354 verify_the_heap(k, "after ");
1355 }
1356
1357 void HeapShared::clear_archived_roots_of(Klass* k) {
1358 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1359 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1360 if (record != nullptr) {
1361 Array<int>* entry_field_records = record->entry_field_records();
1362 if (entry_field_records != nullptr) {
1363 int efr_len = entry_field_records->length();
1364 assert(efr_len % 2 == 0, "sanity");
1365 for (int i = 0; i < efr_len; i += 2) {
1366 int root_index = entry_field_records->at(i+1);
1367 clear_root(root_index);
1368 }
1369 }
1370 }
1371 }
1372
1373 // Push all oop fields (or oop array elemenets in case of an objArray) in
1374 // _referencing_obj onto the _stack.
1375 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1376 PendingOopStack* _stack;
1377 GrowableArray<oop> _found_oop_fields;
1378 int _level;
1379 bool _record_klasses_only;
1380 KlassSubGraphInfo* _subgraph_info;
1381 oop _referencing_obj;
1382 bool _is_java_lang_ref;
1383 public:
1384 OopFieldPusher(PendingOopStack* stack,
1385 int level,
1386 bool record_klasses_only,
1387 KlassSubGraphInfo* subgraph_info,
1388 oop orig) :
1389 _stack(stack),
1390 _found_oop_fields(),
1391 _level(level),
1392 _record_klasses_only(record_klasses_only),
1393 _subgraph_info(subgraph_info),
1394 _referencing_obj(orig) {
1395 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1396 }
1397 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1398 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1399
1400 ~OopFieldPusher() {
1401 while (_found_oop_fields.length() > 0) {
1402 // This produces the exact same traversal order as the previous version
1403 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1404 // walking the oop fields in _referencing_obj by ascending field offsets.
1405 oop obj = _found_oop_fields.pop();
1406 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1407 }
1408 }
1409
1410 protected:
1411 template <class T> void do_oop_work(T *p) {
1412 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1413 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1414 if (!CompressedOops::is_null(obj)) {
1415 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1416 // Do not follow these fields. They will be cleared to null.
1417 return;
1418 }
1419
1420 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1421 ResourceMark rm;
1422 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1423 _referencing_obj->klass()->external_name(), field_offset,
1424 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1425 if (log_is_enabled(Trace, aot, heap)) {
1426 LogTarget(Trace, aot, heap) log;
1427 LogStream out(log);
1428 obj->print_on(&out);
1429 }
1430 }
1431
1432 _found_oop_fields.push(obj);
1433 }
1434 }
1435
1436 public:
1437 oop referencing_obj() { return _referencing_obj; }
1438 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1439 };
1440
1441 // Checks if an oop has any non-null oop fields
1442 class PointsToOopsChecker : public BasicOopIterateClosure {
1443 bool _result;
1444
1445 template <class T> void check(T *p) {
1446 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1447 }
1448
1449 public:
1450 PointsToOopsChecker() : _result(false) {}
1451 void do_oop(narrowOop *p) { check(p); }
1452 void do_oop( oop *p) { check(p); }
1453 bool result() { return _result; }
1454 };
1455
1456 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1457 PointsToOopsChecker points_to_oops_checker;
1458 obj->oop_iterate(&points_to_oops_checker);
1459 return CachedOopInfo(referrer, points_to_oops_checker.result());
1460 }
1461
1462 void HeapShared::init_box_classes(TRAPS) {
1463 if (ArchiveHeapLoader::is_in_use()) {
1464 vmClasses::Boolean_klass()->initialize(CHECK);
1465 vmClasses::Character_klass()->initialize(CHECK);
1466 vmClasses::Float_klass()->initialize(CHECK);
1467 vmClasses::Double_klass()->initialize(CHECK);
1468 vmClasses::Byte_klass()->initialize(CHECK);
1469 vmClasses::Short_klass()->initialize(CHECK);
1470 vmClasses::Integer_klass()->initialize(CHECK);
1471 vmClasses::Long_klass()->initialize(CHECK);
1472 vmClasses::Void_klass()->initialize(CHECK);
1473 }
1474 }
1475
1476 // (1) If orig_obj has not been archived yet, archive it.
1477 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1478 // trace all objects that are reachable from it, and make sure these objects are archived.
1479 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1480 // were already archived when this function is called)
1481 bool HeapShared::archive_reachable_objects_from(int level,
1482 KlassSubGraphInfo* subgraph_info,
1483 oop orig_obj) {
1484 assert(orig_obj != nullptr, "must be");
1485 PendingOopStack stack;
1486 stack.push(PendingOop(orig_obj, nullptr, level));
1487
1488 while (stack.length() > 0) {
1489 PendingOop po = stack.pop();
1490 _object_being_archived = po;
1491 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1492 _object_being_archived = PendingOop();
1493
1494 if (!status) {
1495 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1496 // as the Java code will take care of initializing this field dynamically.
1497 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1498 return false;
1499 }
1500 }
1501
1502 return true;
1503 }
1504
1505 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1506 oop orig_obj, oop referrer) {
1507 assert(orig_obj != nullptr, "must be");
1508 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1509 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1510 // If you get an error here, you probably made a change in the JDK library that has added
1511 // these objects that are referenced (directly or indirectly) by static fields.
1512 ResourceMark rm;
1513 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1514 debug_trace();
1515 MetaspaceShared::unrecoverable_writing_error();
1516 }
1517
1518 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1519 ResourceMark rm;
1520 LogTarget(Debug, aot, heap) log;
1521 LogStream out(log);
1522 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1523 Klass* k = java_lang_Class::as_Klass(orig_obj);
1524 if (k != nullptr) {
1525 out.print("%s", k->external_name());
1526 } else {
1527 out.print("primitive");
1528 }
1529 out.print_cr("; scratch mirror = " PTR_FORMAT,
1530 p2i(scratch_java_mirror(orig_obj)));
1531 }
1532
1533 if (java_lang_Class::is_instance(orig_obj)) {
1534 Klass* k = java_lang_Class::as_Klass(orig_obj);
1535 if (RegeneratedClasses::has_been_regenerated(k)) {
1536 orig_obj = RegeneratedClasses::get_regenerated_object(k)->java_mirror();
1537 }
1538 }
1539
1540 if (CDSConfig::is_initing_classes_at_dump_time()) {
1541 if (java_lang_Class::is_instance(orig_obj)) {
1542 orig_obj = scratch_java_mirror(orig_obj);
1543 assert(orig_obj != nullptr, "must be archived");
1544 }
1545 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1546 // Without CDSConfig::is_initing_classes_at_dump_time(), we only allow archived objects to
1547 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1548 // very early by HeapShared::init_box_classes().
1549 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1550 || java_lang_Class::is_primitive(orig_obj)
1551 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1552 || orig_obj == vmClasses::Character_klass()->java_mirror()
1553 || orig_obj == vmClasses::Float_klass()->java_mirror()
1554 || orig_obj == vmClasses::Double_klass()->java_mirror()
1555 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1556 || orig_obj == vmClasses::Short_klass()->java_mirror()
1557 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1558 || orig_obj == vmClasses::Long_klass()->java_mirror()
1559 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1560 orig_obj = scratch_java_mirror(orig_obj);
1561 assert(orig_obj != nullptr, "must be archived");
1562 } else {
1563 // If you get an error here, you probably made a change in the JDK library that has added a Class
1564 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1565 // defined at the top of this file.
1566 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1567 debug_trace();
1568 MetaspaceShared::unrecoverable_writing_error();
1569 }
1570 }
1571
1572 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1573 // orig_obj has already been archived and traced. Nothing more to do.
1574 return true;
1575 } else {
1576 set_has_been_seen_during_subgraph_recording(orig_obj);
1577 }
1578
1579 bool already_archived = has_been_archived(orig_obj);
1580 bool record_klasses_only = already_archived;
1581 if (!already_archived) {
1582 ++_num_new_archived_objs;
1583 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1584 // Skip archiving the sub-graph referenced from the current entry field.
1585 ResourceMark rm;
1586 log_error(aot, heap)(
1587 "Cannot archive the sub-graph referenced from %s object ("
1588 PTR_FORMAT ") size %zu, skipped.",
1589 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1590 if (level == 1) {
1591 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1592 // as the Java code will take care of initializing this field dynamically.
1593 return false;
1594 } else {
1595 // We don't know how to handle an object that has been archived, but some of its reachable
1596 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1597 // we have a real use case.
1598 MetaspaceShared::unrecoverable_writing_error();
1599 }
1600 }
1601 }
1602
1603 Klass *orig_k = orig_obj->klass();
1604 subgraph_info->add_subgraph_object_klass(orig_k);
1605
1606 {
1607 // Find all the oops that are referenced by orig_obj, push them onto the stack
1608 // so we can work on them next.
1609 ResourceMark rm;
1610 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1611 orig_obj->oop_iterate(&pusher);
1612 }
1613
1614 if (CDSConfig::is_initing_classes_at_dump_time()) {
1615 // The enum klasses are archived with aot-initialized mirror.
1616 // See AOTClassInitializer::can_archive_initialized_mirror().
1617 } else {
1618 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1619 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1620 }
1621 }
1622
1623 return true;
1624 }
1625
1626 //
1627 // Start from the given static field in a java mirror and archive the
1628 // complete sub-graph of java heap objects that are reached directly
1629 // or indirectly from the starting object by following references.
1630 // Sub-graph archiving restrictions (current):
1631 //
1632 // - All classes of objects in the archived sub-graph (including the
1633 // entry class) must be boot class only.
1634 // - No java.lang.Class instance (java mirror) can be included inside
1635 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1636 //
1637 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1638 //
1639 // 1) Java object sub-graph archiving starts from a given static field
1640 // within a Class instance (java mirror). If the static field is a
1641 // reference field and points to a non-null java object, proceed to
1642 // the next step.
1643 //
1644 // 2) Archives the referenced java object. If an archived copy of the
1645 // current object already exists, updates the pointer in the archived
1646 // copy of the referencing object to point to the current archived object.
1647 // Otherwise, proceed to the next step.
1648 //
1649 // 3) Follows all references within the current java object and recursively
1650 // archive the sub-graph of objects starting from each reference.
1651 //
1652 // 4) Updates the pointer in the archived copy of referencing object to
1653 // point to the current archived object.
1654 //
1655 // 5) The Klass of the current java object is added to the list of Klasses
1656 // for loading and initializing before any object in the archived graph can
1657 // be accessed at runtime.
1658 //
1659 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1660 const char* klass_name,
1661 int field_offset,
1662 const char* field_name) {
1663 assert(CDSConfig::is_dumping_heap(), "dump time only");
1664 assert(k->defined_by_boot_loader(), "must be boot class");
1665
1666 oop m = k->java_mirror();
1667
1668 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1669 oop f = m->obj_field(field_offset);
1670
1671 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1672
1673 if (!CompressedOops::is_null(f)) {
1674 if (log_is_enabled(Trace, aot, heap)) {
1675 LogTarget(Trace, aot, heap) log;
1676 LogStream out(log);
1677 f->print_on(&out);
1678 }
1679
1680 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1681 if (!success) {
1682 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1683 klass_name, field_name);
1684 } else {
1685 // Note: the field value is not preserved in the archived mirror.
1686 // Record the field as a new subGraph entry point. The recorded
1687 // information is restored from the archive at runtime.
1688 subgraph_info->add_subgraph_entry_field(field_offset, f);
1689 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1690 }
1691 } else {
1692 // The field contains null, we still need to record the entry point,
1693 // so it can be restored at runtime.
1694 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1695 }
1696 }
1697
1698 #ifndef PRODUCT
1699 class VerifySharedOopClosure: public BasicOopIterateClosure {
1700 public:
1701 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1702 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1703
1704 protected:
1705 template <class T> void do_oop_work(T *p) {
1706 oop obj = RawAccess<>::oop_load(p);
1707 if (!CompressedOops::is_null(obj)) {
1708 HeapShared::verify_reachable_objects_from(obj);
1709 }
1710 }
1711 };
1712
1713 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1714 assert(CDSConfig::is_dumping_heap(), "dump time only");
1715 assert(k->defined_by_boot_loader(), "must be boot class");
1716
1717 oop m = k->java_mirror();
1718 oop f = m->obj_field(field_offset);
1719 if (!CompressedOops::is_null(f)) {
1720 verify_subgraph_from(f);
1721 }
1722 }
1723
1724 void HeapShared::verify_subgraph_from(oop orig_obj) {
1725 if (!has_been_archived(orig_obj)) {
1726 // It's OK for the root of a subgraph to be not archived. See comments in
1727 // archive_reachable_objects_from().
1728 return;
1729 }
1730
1731 // Verify that all objects reachable from orig_obj are archived.
1732 init_seen_objects_table();
1733 verify_reachable_objects_from(orig_obj);
1734 delete_seen_objects_table();
1735 }
1736
1737 void HeapShared::verify_reachable_objects_from(oop obj) {
1738 _num_total_verifications ++;
1739 if (java_lang_Class::is_instance(obj)) {
1740 obj = scratch_java_mirror(obj);
1741 assert(obj != nullptr, "must be");
1742 }
1743 if (!has_been_seen_during_subgraph_recording(obj)) {
1744 set_has_been_seen_during_subgraph_recording(obj);
1745 assert(has_been_archived(obj), "must be");
1746 VerifySharedOopClosure walker;
1747 obj->oop_iterate(&walker);
1748 }
1749 }
1750 #endif
1751
1752 void HeapShared::check_special_subgraph_classes() {
1753 if (CDSConfig::is_initing_classes_at_dump_time()) {
1754 // We can have aot-initialized classes (such as Enums) that can reference objects
1755 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
1756 // aot-initialize classes that are "safe".
1757 //
1758 // TODO: we need an automatic tool that checks the safety of aot-initialized
1759 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
1760 return;
1761 } else {
1762 // In this case, the special subgraph should contain a few specific types
1763 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
1764 int num = klasses->length();
1765 for (int i = 0; i < num; i++) {
1766 Klass* subgraph_k = klasses->at(i);
1767 Symbol* name = subgraph_k->name();
1768 if (subgraph_k->is_instance_klass() &&
1769 name != vmSymbols::java_lang_Class() &&
1770 name != vmSymbols::java_lang_String() &&
1771 name != vmSymbols::java_lang_ArithmeticException() &&
1772 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
1773 name != vmSymbols::java_lang_ArrayStoreException() &&
1774 name != vmSymbols::java_lang_ClassCastException() &&
1775 name != vmSymbols::java_lang_InternalError() &&
1776 name != vmSymbols::java_lang_NullPointerException()) {
1777 ResourceMark rm;
1778 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
1779 }
1780 }
1781 }
1782 }
1783
1784 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
1785 HeapShared::PendingOop HeapShared::_object_being_archived;
1786 int HeapShared::_num_new_walked_objs;
1787 int HeapShared::_num_new_archived_objs;
1788 int HeapShared::_num_old_recorded_klasses;
1789
1790 int HeapShared::_num_total_subgraph_recordings = 0;
1791 int HeapShared::_num_total_walked_objs = 0;
1792 int HeapShared::_num_total_archived_objs = 0;
1793 int HeapShared::_num_total_recorded_klasses = 0;
1794 int HeapShared::_num_total_verifications = 0;
1795
1796 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1797 return _seen_objects_table->get(obj) != nullptr;
1798 }
1799
1800 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1801 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1802 _seen_objects_table->put_when_absent(obj, true);
1803 _seen_objects_table->maybe_grow();
1804 ++ _num_new_walked_objs;
1805 }
1806
1807 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1808 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1809 init_subgraph_info(k, is_full_module_graph);
1810 init_seen_objects_table();
1811 _num_new_walked_objs = 0;
1812 _num_new_archived_objs = 0;
1813 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1814 }
1815
1816 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1817 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1818 _num_old_recorded_klasses;
1819 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
1820 "walked %d objs, archived %d new objs, recorded %d classes",
1821 class_name, _num_new_walked_objs, _num_new_archived_objs,
1822 num_new_recorded_klasses);
1823
1824 delete_seen_objects_table();
1825
1826 _num_total_subgraph_recordings ++;
1827 _num_total_walked_objs += _num_new_walked_objs;
1828 _num_total_archived_objs += _num_new_archived_objs;
1829 _num_total_recorded_klasses += num_new_recorded_klasses;
1830 }
1831
1832 class ArchivableStaticFieldFinder: public FieldClosure {
1833 InstanceKlass* _ik;
1834 Symbol* _field_name;
1835 bool _found;
1836 int _offset;
1837 public:
1838 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1839 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1840
1841 virtual void do_field(fieldDescriptor* fd) {
1842 if (fd->name() == _field_name) {
1843 assert(!_found, "fields can never be overloaded");
1844 if (is_reference_type(fd->field_type())) {
1845 _found = true;
1846 _offset = fd->offset();
1847 }
1848 }
1849 }
1850 bool found() { return _found; }
1851 int offset() { return _offset; }
1852 };
1853
1854 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1855 TRAPS) {
1856 for (int i = 0; fields[i].valid(); i++) {
1857 ArchivableStaticFieldInfo* info = &fields[i];
1858 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1859 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1860 ResourceMark rm; // for stringStream::as_string() etc.
1861
1862 #ifndef PRODUCT
1863 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
1864 const char* test_class_name = ArchiveHeapTestClass;
1865 #else
1866 bool is_test_class = false;
1867 const char* test_class_name = ""; // avoid C++ printf checks warnings.
1868 #endif
1869
1870 if (is_test_class) {
1871 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
1872 }
1873
1874 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
1875 if (HAS_PENDING_EXCEPTION) {
1876 CLEAR_PENDING_EXCEPTION;
1877 stringStream st;
1878 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
1879 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1880 }
1881
1882 if (!k->is_instance_klass()) {
1883 stringStream st;
1884 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
1885 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1886 }
1887
1888 InstanceKlass* ik = InstanceKlass::cast(k);
1889 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
1890 "Only support boot classes");
1891
1892 if (is_test_class) {
1893 if (ik->module()->is_named()) {
1894 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
1895 // core-lib classes. You need to at least append to the bootclasspath.
1896 stringStream st;
1897 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
1898 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1899 }
1900
1901 if (ik->package() != nullptr) {
1902 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
1903 stringStream st;
1904 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
1905 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1906 }
1907 } else {
1908 if (ik->module()->name() != vmSymbols::java_base()) {
1909 // We don't want to deal with cases when a module is unavailable at runtime.
1910 // FUTURE -- load from archived heap only when module graph has not changed
1911 // between dump and runtime.
1912 stringStream st;
1913 st.print("%s is not in java.base module", info->klass_name);
1914 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1915 }
1916 }
1917
1918 if (is_test_class) {
1919 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
1920 }
1921 ik->initialize(CHECK);
1922
1923 ArchivableStaticFieldFinder finder(ik, field_name);
1924 ik->do_local_static_fields(&finder);
1925 if (!finder.found()) {
1926 stringStream st;
1927 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
1928 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1929 }
1930
1931 info->klass = ik;
1932 info->offset = finder.offset();
1933 }
1934 }
1935
1936 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1937 assert(CDSConfig::is_dumping_heap(), "must be");
1938 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
1939 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
1940 if (CDSConfig::is_dumping_full_module_graph()) {
1941 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
1942 }
1943 }
1944
1945 #ifndef PRODUCT
1946 void HeapShared::setup_test_class(const char* test_class_name) {
1947 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
1948 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
1949 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
1950 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
1951
1952 if (test_class_name != nullptr) {
1953 p[num_slots - 2].klass_name = test_class_name;
1954 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
1955 }
1956 }
1957
1958 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
1959 // during runtime. This may be called before the module system is initialized so
1960 // we cannot rely on InstanceKlass::module(), etc.
1961 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
1962 if (_test_class != nullptr) {
1963 if (ik == _test_class) {
1964 return true;
1965 }
1966 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
1967 if (klasses == nullptr) {
1968 return false;
1969 }
1970
1971 for (int i = 0; i < klasses->length(); i++) {
1972 Klass* k = klasses->at(i);
1973 if (k == ik) {
1974 Symbol* name;
1975 if (k->is_instance_klass()) {
1976 name = InstanceKlass::cast(k)->name();
1977 } else if (k->is_objArray_klass()) {
1978 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
1979 if (!bk->is_instance_klass()) {
1980 return false;
1981 }
1982 name = bk->name();
1983 } else {
1984 return false;
1985 }
1986
1987 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
1988 // to be:
1989 // (A) java.base classes (which must not be in the unnamed module)
1990 // (B) test classes which must be in the unnamed package of the unnamed module.
1991 // So if we see a '/' character in the class name, it must be in (A);
1992 // otherwise it must be in (B).
1993 if (name->index_of_at(0, "/", 1) >= 0) {
1994 return false; // (A)
1995 }
1996
1997 return true; // (B)
1998 }
1999 }
2000 }
2001
2002 return false;
2003 }
2004
2005 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2006 Klass* k = _test_class;
2007 if (k != nullptr && ArchiveHeapLoader::is_in_use()) {
2008 JavaThread* THREAD = current;
2009 ExceptionMark em(THREAD);
2010 const ArchivedKlassSubGraphInfoRecord* record =
2011 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2012
2013 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2014 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2015 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2016 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2017 if (record != nullptr) {
2018 init_archived_fields_for(k, record);
2019 }
2020 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2021 }
2022 }
2023 #endif
2024
2025 void HeapShared::init_for_dumping(TRAPS) {
2026 if (CDSConfig::is_dumping_heap()) {
2027 setup_test_class(ArchiveHeapTestClass);
2028 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
2029 init_subgraph_entry_fields(CHECK);
2030 }
2031 }
2032
2033 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2034 bool is_full_module_graph) {
2035 _num_total_subgraph_recordings = 0;
2036 _num_total_walked_objs = 0;
2037 _num_total_archived_objs = 0;
2038 _num_total_recorded_klasses = 0;
2039 _num_total_verifications = 0;
2040
2041 // For each class X that has one or more archived fields:
2042 // [1] Dump the subgraph of each archived field
2043 // [2] Create a list of all the class of the objects that can be reached
2044 // by any of these static fields.
2045 // At runtime, these classes are initialized before X's archived fields
2046 // are restored by HeapShared::initialize_from_archived_subgraph().
2047 for (int i = 0; fields[i].valid(); ) {
2048 ArchivableStaticFieldInfo* info = &fields[i];
2049 const char* klass_name = info->klass_name;
2050 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2051
2052 // If you have specified consecutive fields of the same klass in
2053 // fields[], these will be archived in the same
2054 // {start_recording_subgraph ... done_recording_subgraph} pass to
2055 // save time.
2056 for (; fields[i].valid(); i++) {
2057 ArchivableStaticFieldInfo* f = &fields[i];
2058 if (f->klass_name != klass_name) {
2059 break;
2060 }
2061
2062 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2063 f->offset, f->field_name);
2064 }
2065 done_recording_subgraph(info->klass, klass_name);
2066 }
2067
2068 log_info(aot, heap)("Archived subgraph records = %d",
2069 _num_total_subgraph_recordings);
2070 log_info(aot, heap)(" Walked %d objects", _num_total_walked_objs);
2071 log_info(aot, heap)(" Archived %d objects", _num_total_archived_objs);
2072 log_info(aot, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
2073
2074 #ifndef PRODUCT
2075 for (int i = 0; fields[i].valid(); i++) {
2076 ArchivableStaticFieldInfo* f = &fields[i];
2077 verify_subgraph_from_static_field(f->klass, f->offset);
2078 }
2079 log_info(aot, heap)(" Verified %d references", _num_total_verifications);
2080 #endif
2081 }
2082
2083 // Keep track of the contents of the archived interned string table. This table
2084 // is used only by CDSHeapVerifier.
2085 void HeapShared::add_to_dumped_interned_strings(oop string) {
2086 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
2087 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(string), "must be");
2088 bool created;
2089 _dumped_interned_strings->put_if_absent(string, true, &created);
2090 if (created) {
2091 // Prevent string deduplication from changing the value field to
2092 // something not in the archive.
2093 java_lang_String::set_deduplication_forbidden(string);
2094 _dumped_interned_strings->maybe_grow();
2095 }
2096 }
2097
2098 bool HeapShared::is_dumped_interned_string(oop o) {
2099 return _dumped_interned_strings->get(o) != nullptr;
2100 }
2101
2102 void HeapShared::debug_trace() {
2103 ResourceMark rm;
2104 oop referrer = _object_being_archived.referrer();
2105 if (referrer != nullptr) {
2106 LogStream ls(Log(aot, heap)::error());
2107 ls.print_cr("Reference trace");
2108 CDSHeapVerifier::trace_to_root(&ls, referrer);
2109 }
2110 }
2111
2112 #ifndef PRODUCT
2113 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2114 // region. This way we can quickly relocate all the pointers without using
2115 // BasicOopIterateClosure at runtime.
2116 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2117 void* _start;
2118 BitMap *_oopmap;
2119 int _num_total_oops;
2120 int _num_null_oops;
2121 public:
2122 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2123 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2124
2125 virtual void do_oop(narrowOop* p) {
2126 assert(UseCompressedOops, "sanity");
2127 _num_total_oops ++;
2128 narrowOop v = *p;
2129 if (!CompressedOops::is_null(v)) {
2130 size_t idx = p - (narrowOop*)_start;
2131 _oopmap->set_bit(idx);
2132 } else {
2133 _num_null_oops ++;
2134 }
2135 }
2136 virtual void do_oop(oop* p) {
2137 assert(!UseCompressedOops, "sanity");
2138 _num_total_oops ++;
2139 if ((*p) != nullptr) {
2140 size_t idx = p - (oop*)_start;
2141 _oopmap->set_bit(idx);
2142 } else {
2143 _num_null_oops ++;
2144 }
2145 }
2146 int num_total_oops() const { return _num_total_oops; }
2147 int num_null_oops() const { return _num_null_oops; }
2148 };
2149 #endif
2150
2151 void HeapShared::count_allocation(size_t size) {
2152 _total_obj_count ++;
2153 _total_obj_size += size;
2154 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2155 if (size <= (size_t(1) << i)) {
2156 _alloc_count[i] ++;
2157 _alloc_size[i] += size;
2158 return;
2159 }
2160 }
2161 }
2162
2163 static double avg_size(size_t size, size_t count) {
2164 double avg = 0;
2165 if (count > 0) {
2166 avg = double(size * HeapWordSize) / double(count);
2167 }
2168 return avg;
2169 }
2170
2171 void HeapShared::print_stats() {
2172 size_t huge_count = _total_obj_count;
2173 size_t huge_size = _total_obj_size;
2174
2175 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2176 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2177 size_t count = _alloc_count[i];
2178 size_t size = _alloc_size[i];
2179 log_info(aot, heap)("%8zu objects are <= %-6zu"
2180 " bytes (total %8zu bytes, avg %8.1f bytes)",
2181 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2182 huge_count -= count;
2183 huge_size -= size;
2184 }
2185
2186 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2187 ", avg %8.1f bytes)",
2188 huge_count, huge_size * HeapWordSize,
2189 avg_size(huge_size, huge_count));
2190 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2191 ", avg %8.1f bytes)",
2192 _total_obj_count, _total_obj_size * HeapWordSize,
2193 avg_size(_total_obj_size, _total_obj_count));
2194 }
2195
2196 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2197 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2198 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2199 if (k == nullptr) {
2200 return false;
2201 } else {
2202 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2203 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2204 fieldDescriptor fd;
2205 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2206 oop m = k->java_mirror();
2207 oop f = m->obj_field(fd.offset());
2208 if (CompressedOops::is_null(f)) {
2209 return false;
2210 }
2211 } else {
2212 return false;
2213 }
2214 }
2215 return true;
2216 }
2217
2218 #endif // INCLUDE_CDS_JAVA_HEAP