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
509 oop orig_mirror;
510 if (RegeneratedClasses::is_regenerated_object(ik)) {
511 InstanceKlass* orig_ik = RegeneratedClasses::get_original_object(ik);
512 precond(orig_ik->is_initialized());
513 orig_mirror = orig_ik->java_mirror();
514 } else {
515 precond(ik->is_initialized());
516 orig_mirror = ik->java_mirror();
517 }
518
519 oop m = scratch_java_mirror(ik);
520 int nfields = 0;
521 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
522 if (fs.access_flags().is_static()) {
523 fieldDescriptor& fd = fs.field_descriptor();
524 int offset = fd.offset();
525 switch (fd.field_type()) {
526 case T_OBJECT:
527 case T_ARRAY:
528 {
529 oop field_obj = orig_mirror->obj_field(offset);
530 if (offset == java_lang_Class::reflection_data_offset()) {
531 // Class::reflectData use SoftReference, which cannot be archived. Set it
532 // to null and it will be recreated at runtime.
533 field_obj = nullptr;
534 }
535 m->obj_field_put(offset, field_obj);
536 if (field_obj != nullptr) {
537 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
538 assert(success, "sanity");
539 }
540 }
541 break;
542 case T_BOOLEAN:
543 m->bool_field_put(offset, orig_mirror->bool_field(offset));
544 break;
545 case T_BYTE:
546 m->byte_field_put(offset, orig_mirror->byte_field(offset));
547 break;
548 case T_SHORT:
549 m->short_field_put(offset, orig_mirror->short_field(offset));
550 break;
551 case T_CHAR:
552 m->char_field_put(offset, orig_mirror->char_field(offset));
553 break;
554 case T_INT:
555 m->int_field_put(offset, orig_mirror->int_field(offset));
556 break;
557 case T_LONG:
558 m->long_field_put(offset, orig_mirror->long_field(offset));
559 break;
560 case T_FLOAT:
561 m->float_field_put(offset, orig_mirror->float_field(offset));
562 break;
563 case T_DOUBLE:
564 m->double_field_put(offset, orig_mirror->double_field(offset));
565 break;
566 default:
567 ShouldNotReachHere();
568 }
569 nfields ++;
570 }
571 }
572
573 oop class_data = java_lang_Class::class_data(orig_mirror);
574 java_lang_Class::set_class_data(m, class_data);
575 if (class_data != nullptr) {
576 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
577 assert(success, "sanity");
578 }
579
580 if (log_is_enabled(Debug, aot, init)) {
581 ResourceMark rm;
582 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
583 ik->is_hidden() ? " (hidden)" : "",
584 ik->is_enum_subclass() ? " (enum)" : "");
585 }
586 }
587
588 static void copy_java_mirror_hashcode(oop orig_mirror, oop scratch_m) {
589 // We need to retain the identity_hash, because it may have been used by some hashtables
590 // in the shared heap.
591 if (!orig_mirror->fast_no_hash_check()) {
592 intptr_t src_hash = orig_mirror->identity_hash();
593 if (UseCompactObjectHeaders) {
594 narrowKlass nk = CompressedKlassPointers::encode(orig_mirror->klass());
595 scratch_m->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
596 } else {
597 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
598 }
599 assert(scratch_m->mark().is_unlocked(), "sanity");
600
601 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
602 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
603 }
604 }
605
606 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
607 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
608 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
609 if (rr != nullptr && !ArchiveHeapWriter::is_too_large_to_archive(rr)) {
610 return HeapShared::scratch_resolved_references(src_ik->constants());
611 }
612 }
613 return nullptr;
614 }
615
616 void HeapShared::archive_strings() {
617 oop shared_strings_array = StringTable::init_shared_strings_array();
618 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, shared_strings_array);
619 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
620 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
621 }
622
623 int HeapShared::archive_exception_instance(oop exception) {
624 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
625 assert(success, "sanity");
626 return append_root(exception);
627 }
628
629 void HeapShared::mark_native_pointers(oop orig_obj) {
630 if (java_lang_Class::is_instance(orig_obj)) {
631 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::klass_offset());
632 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::array_klass_offset());
633 } else if (java_lang_invoke_ResolvedMethodName::is_instance(orig_obj)) {
634 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_invoke_ResolvedMethodName::vmtarget_offset());
635 }
636 }
637
638 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
639 CachedOopInfo* info = archived_object_cache()->get(src_obj);
640 assert(info != nullptr, "must be");
641 has_oop_pointers = info->has_oop_pointers();
642 has_native_pointers = info->has_native_pointers();
643 }
644
645 void HeapShared::set_has_native_pointers(oop src_obj) {
646 CachedOopInfo* info = archived_object_cache()->get(src_obj);
647 assert(info != nullptr, "must be");
648 info->set_has_native_pointers();
649 }
650
651 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
652 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
653 void HeapShared::start_scanning_for_oops() {
654 {
655 NoSafepointVerifier nsv;
656
657 // The special subgraph doesn't belong to any class. We use Object_klass() here just
658 // for convenience.
659 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
660
661 // Cache for recording where the archived objects are copied to
662 create_archived_object_cache();
663
664 if (UseCompressedOops || UseG1GC) {
665 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
666 UseCompressedOops ? p2i(CompressedOops::begin()) :
667 p2i((address)G1CollectedHeap::heap()->reserved().start()),
668 UseCompressedOops ? p2i(CompressedOops::end()) :
669 p2i((address)G1CollectedHeap::heap()->reserved().end()));
670 }
671
672 archive_subgraphs();
673 }
674
675 init_seen_objects_table();
676 Universe::archive_exception_instances();
677 }
678
679 void HeapShared::end_scanning_for_oops() {
680 archive_strings();
681 delete_seen_objects_table();
682 }
683
684 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
685 {
686 NoSafepointVerifier nsv;
687 CDSHeapVerifier::verify();
688 check_special_subgraph_classes();
689 }
690
691 StringTable::write_shared_table();
692 ArchiveHeapWriter::write(_pending_roots, heap_info);
693
694 ArchiveBuilder::OtherROAllocMark mark;
695 write_subgraph_info_table();
696 }
697
698 void HeapShared::scan_java_mirror(oop orig_mirror) {
699 oop m = scratch_java_mirror(orig_mirror);
700 if (m != nullptr) { // nullptr if for custom class loader
701 copy_java_mirror_hashcode(orig_mirror, m);
702 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
703 assert(success, "sanity");
704 }
705 }
706
707 void HeapShared::scan_java_class(Klass* orig_k) {
708 scan_java_mirror(orig_k->java_mirror());
709
710 if (orig_k->is_instance_klass()) {
711 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
712 orig_ik->constants()->prepare_resolved_references_for_archiving();
713 objArrayOop rr = get_archived_resolved_references(orig_ik);
714 if (rr != nullptr) {
715 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
716 assert(success, "must be");
717 }
718 }
719 }
720
721 void HeapShared::archive_subgraphs() {
722 assert(CDSConfig::is_dumping_heap(), "must be");
723
724 archive_object_subgraphs(archive_subgraph_entry_fields,
725 false /* is_full_module_graph */);
726
727 if (CDSConfig::is_dumping_full_module_graph()) {
728 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
729 true /* is_full_module_graph */);
730 Modules::verify_archived_modules();
731 }
732 }
733
734 //
735 // Subgraph archiving support
736 //
737 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
738 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
739
740 // Get the subgraph_info for Klass k. A new subgraph_info is created if
741 // there is no existing one for k. The subgraph_info records the "buffered"
742 // address of the class.
743 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
744 assert(CDSConfig::is_dumping_heap(), "dump time only");
745 bool created;
746 KlassSubGraphInfo* info =
747 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
748 &created);
749 assert(created, "must not initialize twice");
750 return info;
751 }
752
753 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
754 assert(CDSConfig::is_dumping_heap(), "dump time only");
755 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
756 assert(info != nullptr, "must have been initialized");
757 return info;
758 }
759
760 // Add an entry field to the current KlassSubGraphInfo.
761 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
762 assert(CDSConfig::is_dumping_heap(), "dump time only");
763 if (_subgraph_entry_fields == nullptr) {
764 _subgraph_entry_fields =
765 new (mtClass) GrowableArray<int>(10, mtClass);
766 }
767 _subgraph_entry_fields->append(static_field_offset);
768 _subgraph_entry_fields->append(HeapShared::append_root(v));
769 }
770
771 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
772 // Only objects of boot classes can be included in sub-graph.
773 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
774 assert(CDSConfig::is_dumping_heap(), "dump time only");
775
776 if (_subgraph_object_klasses == nullptr) {
777 _subgraph_object_klasses =
778 new (mtClass) GrowableArray<Klass*>(50, mtClass);
779 }
780
781 if (_k == orig_k) {
782 // Don't add the Klass containing the sub-graph to it's own klass
783 // initialization list.
784 return;
785 }
786
787 if (orig_k->is_instance_klass()) {
788 #ifdef ASSERT
789 InstanceKlass* ik = InstanceKlass::cast(orig_k);
790 if (CDSConfig::is_dumping_method_handles()) {
791 // -XX:AOTInitTestClass must be used carefully in regression tests to
792 // include only classes that are safe to aot-initialize.
793 assert(ik->class_loader() == nullptr ||
794 HeapShared::is_lambda_proxy_klass(ik) ||
795 AOTClassInitializer::has_test_class(),
796 "we can archive only instances of boot classes or lambda proxy classes");
797 } else {
798 assert(ik->class_loader() == nullptr, "must be boot class");
799 }
800 #endif
801 // vmClasses::xxx_klass() are not updated, need to check
802 // the original Klass*
803 if (orig_k == vmClasses::String_klass() ||
804 orig_k == vmClasses::Object_klass()) {
805 // Initialized early during VM initialization. No need to be added
806 // to the sub-graph object class list.
807 return;
808 }
809 check_allowed_klass(InstanceKlass::cast(orig_k));
810 } else if (orig_k->is_objArray_klass()) {
811 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
812 if (abk->is_instance_klass()) {
813 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
814 "must be boot class");
815 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
816 }
817 if (orig_k == Universe::objectArrayKlass()) {
818 // Initialized early during Universe::genesis. No need to be added
819 // to the list.
820 return;
821 }
822 } else {
823 assert(orig_k->is_typeArray_klass(), "must be");
824 // Primitive type arrays are created early during Universe::genesis.
825 return;
826 }
827
828 if (log_is_enabled(Debug, aot, heap)) {
829 if (!_subgraph_object_klasses->contains(orig_k)) {
830 ResourceMark rm;
831 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
832 }
833 }
834
835 _subgraph_object_klasses->append_if_missing(orig_k);
836 _has_non_early_klasses |= is_non_early_klass(orig_k);
837 }
838
839 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
840 #ifndef PRODUCT
841 if (AOTClassInitializer::has_test_class()) {
842 // The tests can cache arbitrary types of objects.
843 return;
844 }
845 #endif
846
847 if (ik->module()->name() == vmSymbols::java_base()) {
848 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
849 return;
850 }
851
852 const char* lambda_msg = "";
853 if (CDSConfig::is_dumping_method_handles()) {
854 lambda_msg = ", or a lambda proxy class";
855 if (HeapShared::is_lambda_proxy_klass(ik) &&
856 (ik->class_loader() == nullptr ||
857 ik->class_loader() == SystemDictionary::java_platform_loader() ||
858 ik->class_loader() == SystemDictionary::java_system_loader())) {
859 return;
860 }
861 }
862
863 #ifndef PRODUCT
864 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
865 // This class is loaded by ArchiveHeapTestClass
866 return;
867 }
868 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
869 #else
870 const char* testcls_msg = "";
871 #endif
872
873 ResourceMark rm;
874 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
875 ik->external_name(), lambda_msg, testcls_msg);
876 MetaspaceShared::unrecoverable_writing_error();
877 }
878
879 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
880 if (k->is_objArray_klass()) {
881 k = ObjArrayKlass::cast(k)->bottom_klass();
882 }
883 if (k->is_instance_klass()) {
884 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
885 ResourceMark rm;
886 log_info(aot, heap)("non-early: %s", k->external_name());
887 return true;
888 } else {
889 return false;
890 }
891 } else {
892 return false;
893 }
894 }
895
896 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
897 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
898 _k = ArchiveBuilder::get_buffered_klass(info->klass());
899 _entry_field_records = nullptr;
900 _subgraph_object_klasses = nullptr;
901 _is_full_module_graph = info->is_full_module_graph();
902
903 if (_is_full_module_graph) {
904 // Consider all classes referenced by the full module graph as early -- we will be
905 // allocating objects of these classes during JVMTI early phase, so they cannot
906 // be processed by (non-early) JVMTI ClassFileLoadHook
907 _has_non_early_klasses = false;
908 } else {
909 _has_non_early_klasses = info->has_non_early_klasses();
910 }
911
912 if (_has_non_early_klasses) {
913 ResourceMark rm;
914 log_info(aot, heap)(
915 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
916 _k->external_name());
917 }
918
919 // populate the entry fields
920 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
921 if (entry_fields != nullptr) {
922 int num_entry_fields = entry_fields->length();
923 assert(num_entry_fields % 2 == 0, "sanity");
924 _entry_field_records =
925 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
926 for (int i = 0 ; i < num_entry_fields; i++) {
927 _entry_field_records->at_put(i, entry_fields->at(i));
928 }
929 }
930
931 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
932 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
933 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
934 if (recorded_klasses != nullptr) {
935 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
936 // programmatically loading a subgraph, we only need to explicitly initialize the classes
937 // that are not aot-inited.
938 int num_to_copy = 0;
939 for (int i = 0; i < recorded_klasses->length(); i++) {
940 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
941 if (!subgraph_k->has_aot_initialized_mirror()) {
942 num_to_copy ++;
943 }
944 }
945
946 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
947 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
948 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
949 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
950 if (subgraph_k->has_aot_initialized_mirror()) {
951 continue;
952 }
953 if (log_is_enabled(Info, aot, heap)) {
954 ResourceMark rm;
955 const char* owner_name = is_special ? "<special>" : _k->external_name();
956 if (subgraph_k->is_instance_klass()) {
957 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
958 }
959 log_info(aot, heap)(
960 "Archived object klass %s (%2d) => %s",
961 owner_name, n, subgraph_k->external_name());
962 }
963 _subgraph_object_klasses->at_put(n, subgraph_k);
964 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
965 n++;
966 }
967 }
968
969 ArchivePtrMarker::mark_pointer(&_k);
970 ArchivePtrMarker::mark_pointer(&_entry_field_records);
971 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
972 }
973
974 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
975 CompactHashtableWriter* _writer;
976 public:
977 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
978
979 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
980 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
981 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
982 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
983 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
984 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
985 _writer->add(hash, delta);
986 }
987 return true; // keep on iterating
988 }
989 };
990
991 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
992 ArchivedKlassSubGraphInfoRecord* record =
993 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
994 record->init(info);
995 if (info == _dump_time_special_subgraph) {
996 _run_time_special_subgraph = record;
997 }
998 return record;
999 }
1000
1001 // Build the records of archived subgraph infos, which include:
1002 // - Entry points to all subgraphs from the containing class mirror. The entry
1003 // points are static fields in the mirror. For each entry point, the field
1004 // offset, and value are recorded in the sub-graph
1005 // info. The value is stored back to the corresponding field at runtime.
1006 // - A list of klasses that need to be loaded/initialized before archived
1007 // java object sub-graph can be accessed at runtime.
1008 void HeapShared::write_subgraph_info_table() {
1009 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1010 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1011 CompactHashtableStats stats;
1012
1013 _run_time_subgraph_info_table.reset();
1014
1015 CompactHashtableWriter writer(d_table->_count, &stats);
1016 CopyKlassSubGraphInfoToArchive copy(&writer);
1017 d_table->iterate(©);
1018 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1019
1020 #ifndef PRODUCT
1021 if (ArchiveHeapTestClass != nullptr) {
1022 size_t len = strlen(ArchiveHeapTestClass) + 1;
1023 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1024 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1025 _archived_ArchiveHeapTestClass = array;
1026 }
1027 #endif
1028 if (log_is_enabled(Info, aot, heap)) {
1029 print_stats();
1030 }
1031 }
1032
1033 void HeapShared::add_root_segment(objArrayOop segment_oop) {
1034 assert(segment_oop != nullptr, "must be");
1035 assert(ArchiveHeapLoader::is_in_use(), "must be");
1036 if (_root_segments == nullptr) {
1037 _root_segments = new GrowableArrayCHeap<OopHandle, mtClassShared>(10);
1038 }
1039 _root_segments->push(OopHandle(Universe::vm_global(), segment_oop));
1040 }
1041
1042 void HeapShared::init_root_segment_sizes(int max_size_elems) {
1043 _root_segment_max_size_elems = max_size_elems;
1044 }
1045
1046 void HeapShared::serialize_tables(SerializeClosure* soc) {
1047
1048 #ifndef PRODUCT
1049 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1050 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1051 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1052 setup_test_class(_test_class_name);
1053 }
1054 #endif
1055
1056 _run_time_subgraph_info_table.serialize_header(soc);
1057 soc->do_ptr(&_run_time_special_subgraph);
1058 }
1059
1060 static void verify_the_heap(Klass* k, const char* which) {
1061 if (VerifyArchivedFields > 0) {
1062 ResourceMark rm;
1063 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1064 which, k->external_name());
1065
1066 VM_Verify verify_op;
1067 VMThread::execute(&verify_op);
1068
1069 if (VerifyArchivedFields > 1 && is_init_completed()) {
1070 // At this time, the oop->klass() of some archived objects in the heap may not
1071 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1072 // have enough information (object size, oop maps, etc) so that a GC can be safely
1073 // performed.
1074 //
1075 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1076 // to check for GC safety.
1077 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1078 which, k->external_name());
1079 FlagSetting fs1(VerifyBeforeGC, true);
1080 FlagSetting fs2(VerifyDuringGC, true);
1081 FlagSetting fs3(VerifyAfterGC, true);
1082 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1083 }
1084 }
1085 }
1086
1087 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1088 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1089 //
1090 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1091 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1092 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1093 void HeapShared::resolve_classes(JavaThread* current) {
1094 assert(CDSConfig::is_using_archive(), "runtime only!");
1095 if (!ArchiveHeapLoader::is_in_use()) {
1096 return; // nothing to do
1097 }
1098 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1099 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1100 }
1101
1102 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1103 for (int i = 0; fields[i].valid(); i++) {
1104 ArchivableStaticFieldInfo* info = &fields[i];
1105 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1106 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1107 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1108 resolve_classes_for_subgraph_of(current, k);
1109 }
1110 }
1111
1112 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1113 JavaThread* THREAD = current;
1114 ExceptionMark em(THREAD);
1115 const ArchivedKlassSubGraphInfoRecord* record =
1116 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1117 if (HAS_PENDING_EXCEPTION) {
1118 CLEAR_PENDING_EXCEPTION;
1119 }
1120 if (record == nullptr) {
1121 clear_archived_roots_of(k);
1122 }
1123 }
1124
1125 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1126 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1127 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1128 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1129 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1130 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1131 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1132 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1133 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1134 }
1135 }
1136
1137 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1138 // - interned strings
1139 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1140 // - ConstantPool::resolved_references()
1141 // - Universe::<xxx>_exception_instance()
1142 //
1143 // For example, if this enum class is initialized at AOT cache assembly time:
1144 //
1145 // enum Fruit {
1146 // APPLE, ORANGE, BANANA;
1147 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1148 // }
1149 //
1150 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1151 // should be initialized before any Java code can access the Fruit class. Note that
1152 // HashSet itself doesn't necessary need to be an aot-initialized class.
1153 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1154 if (!ArchiveHeapLoader::is_in_use()) {
1155 return;
1156 }
1157
1158 assert( _run_time_special_subgraph != nullptr, "must be");
1159 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1160 if (klasses != nullptr) {
1161 for (int pass = 0; pass < 2; pass ++) {
1162 for (int i = 0; i < klasses->length(); i++) {
1163 Klass* k = klasses->at(i);
1164 if (k->class_loader_data() == nullptr) {
1165 // This class is not yet loaded. We will initialize it in a later phase.
1166 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1167 // but k is part of AOTLinkedClassCategory::BOOT2.
1168 continue;
1169 }
1170 if (k->class_loader() == class_loader()) {
1171 if (pass == 0) {
1172 if (k->is_instance_klass()) {
1173 InstanceKlass::cast(k)->link_class(CHECK);
1174 }
1175 } else {
1176 resolve_or_init(k, /*do_init*/true, CHECK);
1177 }
1178 }
1179 }
1180 }
1181 }
1182 }
1183
1184 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1185 JavaThread* THREAD = current;
1186 if (!ArchiveHeapLoader::is_in_use()) {
1187 return; // nothing to do
1188 }
1189
1190 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1191 !CDSConfig::is_using_optimized_module_handling() &&
1192 // archive was created with --module-path
1193 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1194 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1195 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1196 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1197 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1198 AOTClassLocationConfig::runtime()->num_module_paths());
1199 return;
1200 }
1201
1202 ExceptionMark em(THREAD);
1203 const ArchivedKlassSubGraphInfoRecord* record =
1204 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1205
1206 if (HAS_PENDING_EXCEPTION) {
1207 CLEAR_PENDING_EXCEPTION;
1208 // None of the field value will be set if there was an exception when initializing the classes.
1209 // The java code will not see any of the archived objects in the
1210 // subgraphs referenced from k in this case.
1211 return;
1212 }
1213
1214 if (record != nullptr) {
1215 init_archived_fields_for(k, record);
1216 }
1217 }
1218
1219 const ArchivedKlassSubGraphInfoRecord*
1220 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1221 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1222
1223 if (!k->is_shared()) {
1224 return nullptr;
1225 }
1226 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1227 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1228
1229 #ifndef PRODUCT
1230 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1231 _test_class = k;
1232 _test_class_record = record;
1233 }
1234 #endif
1235
1236 // Initialize from archived data. Currently this is done only
1237 // during VM initialization time. No lock is needed.
1238 if (record == nullptr) {
1239 if (log_is_enabled(Info, aot, heap)) {
1240 ResourceMark rm(THREAD);
1241 log_info(aot, heap)("subgraph %s is not recorded",
1242 k->external_name());
1243 }
1244 return nullptr;
1245 } else {
1246 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1247 if (log_is_enabled(Info, aot, heap)) {
1248 ResourceMark rm(THREAD);
1249 log_info(aot, heap)("subgraph %s cannot be used because full module graph is disabled",
1250 k->external_name());
1251 }
1252 return nullptr;
1253 }
1254
1255 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1256 if (log_is_enabled(Info, aot, heap)) {
1257 ResourceMark rm(THREAD);
1258 log_info(aot, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1259 k->external_name());
1260 }
1261 return nullptr;
1262 }
1263
1264 if (log_is_enabled(Info, aot, heap)) {
1265 ResourceMark rm;
1266 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1267 }
1268
1269 resolve_or_init(k, do_init, CHECK_NULL);
1270
1271 // Load/link/initialize the klasses of the objects in the subgraph.
1272 // nullptr class loader is used.
1273 Array<Klass*>* klasses = record->subgraph_object_klasses();
1274 if (klasses != nullptr) {
1275 for (int i = 0; i < klasses->length(); i++) {
1276 Klass* klass = klasses->at(i);
1277 if (!klass->is_shared()) {
1278 return nullptr;
1279 }
1280 resolve_or_init(klass, do_init, CHECK_NULL);
1281 }
1282 }
1283 }
1284
1285 return record;
1286 }
1287
1288 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1289 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1290 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1291 if (k == nullptr) {
1292 return;
1293 }
1294 assert(k->defined_by_boot_loader(), "sanity");
1295 resolve_or_init(k, false, CHECK);
1296 if (do_init) {
1297 resolve_or_init(k, true, CHECK);
1298 }
1299 }
1300
1301 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1302 if (!do_init) {
1303 if (k->class_loader_data() == nullptr) {
1304 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1305 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1306 }
1307 } else {
1308 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1309 if (k->is_instance_klass()) {
1310 InstanceKlass* ik = InstanceKlass::cast(k);
1311 ik->initialize(CHECK);
1312 } else if (k->is_objArray_klass()) {
1313 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1314 oak->initialize(CHECK);
1315 }
1316 }
1317 }
1318
1319 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1320 verify_the_heap(k, "before");
1321
1322 // Load the subgraph entry fields from the record and store them back to
1323 // the corresponding fields within the mirror.
1324 oop m = k->java_mirror();
1325 Array<int>* entry_field_records = record->entry_field_records();
1326 if (entry_field_records != nullptr) {
1327 int efr_len = entry_field_records->length();
1328 assert(efr_len % 2 == 0, "sanity");
1329 for (int i = 0; i < efr_len; i += 2) {
1330 int field_offset = entry_field_records->at(i);
1331 int root_index = entry_field_records->at(i+1);
1332 oop v = get_root(root_index, /*clear=*/true);
1333 if (k->has_aot_initialized_mirror()) {
1334 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1335 } else {
1336 m->obj_field_put(field_offset, v);
1337 }
1338 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1339 }
1340
1341 // Done. Java code can see the archived sub-graphs referenced from k's
1342 // mirror after this point.
1343 if (log_is_enabled(Info, aot, heap)) {
1344 ResourceMark rm;
1345 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1346 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1347 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1348 }
1349 }
1350
1351 verify_the_heap(k, "after ");
1352 }
1353
1354 void HeapShared::clear_archived_roots_of(Klass* k) {
1355 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1356 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1357 if (record != nullptr) {
1358 Array<int>* entry_field_records = record->entry_field_records();
1359 if (entry_field_records != nullptr) {
1360 int efr_len = entry_field_records->length();
1361 assert(efr_len % 2 == 0, "sanity");
1362 for (int i = 0; i < efr_len; i += 2) {
1363 int root_index = entry_field_records->at(i+1);
1364 clear_root(root_index);
1365 }
1366 }
1367 }
1368 }
1369
1370 // Push all oop fields (or oop array elemenets in case of an objArray) in
1371 // _referencing_obj onto the _stack.
1372 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1373 PendingOopStack* _stack;
1374 GrowableArray<oop> _found_oop_fields;
1375 int _level;
1376 bool _record_klasses_only;
1377 KlassSubGraphInfo* _subgraph_info;
1378 oop _referencing_obj;
1379 bool _is_java_lang_ref;
1380 public:
1381 OopFieldPusher(PendingOopStack* stack,
1382 int level,
1383 bool record_klasses_only,
1384 KlassSubGraphInfo* subgraph_info,
1385 oop orig) :
1386 _stack(stack),
1387 _found_oop_fields(),
1388 _level(level),
1389 _record_klasses_only(record_klasses_only),
1390 _subgraph_info(subgraph_info),
1391 _referencing_obj(orig) {
1392 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1393 }
1394 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1395 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1396
1397 ~OopFieldPusher() {
1398 while (_found_oop_fields.length() > 0) {
1399 // This produces the exact same traversal order as the previous version
1400 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1401 // walking the oop fields in _referencing_obj by ascending field offsets.
1402 oop obj = _found_oop_fields.pop();
1403 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1404 }
1405 }
1406
1407 protected:
1408 template <class T> void do_oop_work(T *p) {
1409 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1410 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1411 if (!CompressedOops::is_null(obj)) {
1412 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1413 // Do not follow these fields. They will be cleared to null.
1414 return;
1415 }
1416
1417 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1418 ResourceMark rm;
1419 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1420 _referencing_obj->klass()->external_name(), field_offset,
1421 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1422 if (log_is_enabled(Trace, aot, heap)) {
1423 LogTarget(Trace, aot, heap) log;
1424 LogStream out(log);
1425 obj->print_on(&out);
1426 }
1427 }
1428
1429 _found_oop_fields.push(obj);
1430 }
1431 }
1432
1433 public:
1434 oop referencing_obj() { return _referencing_obj; }
1435 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1436 };
1437
1438 // Checks if an oop has any non-null oop fields
1439 class PointsToOopsChecker : public BasicOopIterateClosure {
1440 bool _result;
1441
1442 template <class T> void check(T *p) {
1443 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1444 }
1445
1446 public:
1447 PointsToOopsChecker() : _result(false) {}
1448 void do_oop(narrowOop *p) { check(p); }
1449 void do_oop( oop *p) { check(p); }
1450 bool result() { return _result; }
1451 };
1452
1453 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1454 PointsToOopsChecker points_to_oops_checker;
1455 obj->oop_iterate(&points_to_oops_checker);
1456 return CachedOopInfo(referrer, points_to_oops_checker.result());
1457 }
1458
1459 void HeapShared::init_box_classes(TRAPS) {
1460 if (ArchiveHeapLoader::is_in_use()) {
1461 vmClasses::Boolean_klass()->initialize(CHECK);
1462 vmClasses::Character_klass()->initialize(CHECK);
1463 vmClasses::Float_klass()->initialize(CHECK);
1464 vmClasses::Double_klass()->initialize(CHECK);
1465 vmClasses::Byte_klass()->initialize(CHECK);
1466 vmClasses::Short_klass()->initialize(CHECK);
1467 vmClasses::Integer_klass()->initialize(CHECK);
1468 vmClasses::Long_klass()->initialize(CHECK);
1469 vmClasses::Void_klass()->initialize(CHECK);
1470 }
1471 }
1472
1473 // (1) If orig_obj has not been archived yet, archive it.
1474 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1475 // trace all objects that are reachable from it, and make sure these objects are archived.
1476 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1477 // were already archived when this function is called)
1478 bool HeapShared::archive_reachable_objects_from(int level,
1479 KlassSubGraphInfo* subgraph_info,
1480 oop orig_obj) {
1481 assert(orig_obj != nullptr, "must be");
1482 PendingOopStack stack;
1483 stack.push(PendingOop(orig_obj, nullptr, level));
1484
1485 while (stack.length() > 0) {
1486 PendingOop po = stack.pop();
1487 _object_being_archived = po;
1488 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1489 _object_being_archived = PendingOop();
1490
1491 if (!status) {
1492 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1493 // as the Java code will take care of initializing this field dynamically.
1494 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1495 return false;
1496 }
1497 }
1498
1499 return true;
1500 }
1501
1502 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1503 oop orig_obj, oop referrer) {
1504 assert(orig_obj != nullptr, "must be");
1505 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1506 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1507 // If you get an error here, you probably made a change in the JDK library that has added
1508 // these objects that are referenced (directly or indirectly) by static fields.
1509 ResourceMark rm;
1510 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1511 debug_trace();
1512 MetaspaceShared::unrecoverable_writing_error();
1513 }
1514
1515 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1516 ResourceMark rm;
1517 LogTarget(Debug, aot, heap) log;
1518 LogStream out(log);
1519 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1520 Klass* k = java_lang_Class::as_Klass(orig_obj);
1521 if (k != nullptr) {
1522 out.print("%s", k->external_name());
1523 } else {
1524 out.print("primitive");
1525 }
1526 out.print_cr("; scratch mirror = " PTR_FORMAT,
1527 p2i(scratch_java_mirror(orig_obj)));
1528 }
1529
1530 if (java_lang_Class::is_instance(orig_obj)) {
1531 Klass* k = java_lang_Class::as_Klass(orig_obj);
1532 if (RegeneratedClasses::has_been_regenerated(k)) {
1533 orig_obj = RegeneratedClasses::get_regenerated_object(k)->java_mirror();
1534 }
1535 }
1536
1537 if (CDSConfig::is_initing_classes_at_dump_time()) {
1538 if (java_lang_Class::is_instance(orig_obj)) {
1539 orig_obj = scratch_java_mirror(orig_obj);
1540 assert(orig_obj != nullptr, "must be archived");
1541 }
1542 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1543 // Without CDSConfig::is_initing_classes_at_dump_time(), we only allow archived objects to
1544 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1545 // very early by HeapShared::init_box_classes().
1546 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1547 || java_lang_Class::is_primitive(orig_obj)
1548 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1549 || orig_obj == vmClasses::Character_klass()->java_mirror()
1550 || orig_obj == vmClasses::Float_klass()->java_mirror()
1551 || orig_obj == vmClasses::Double_klass()->java_mirror()
1552 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1553 || orig_obj == vmClasses::Short_klass()->java_mirror()
1554 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1555 || orig_obj == vmClasses::Long_klass()->java_mirror()
1556 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1557 orig_obj = scratch_java_mirror(orig_obj);
1558 assert(orig_obj != nullptr, "must be archived");
1559 } else {
1560 // If you get an error here, you probably made a change in the JDK library that has added a Class
1561 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1562 // defined at the top of this file.
1563 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1564 debug_trace();
1565 MetaspaceShared::unrecoverable_writing_error();
1566 }
1567 }
1568
1569 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1570 // orig_obj has already been archived and traced. Nothing more to do.
1571 return true;
1572 } else {
1573 set_has_been_seen_during_subgraph_recording(orig_obj);
1574 }
1575
1576 bool already_archived = has_been_archived(orig_obj);
1577 bool record_klasses_only = already_archived;
1578 if (!already_archived) {
1579 ++_num_new_archived_objs;
1580 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1581 // Skip archiving the sub-graph referenced from the current entry field.
1582 ResourceMark rm;
1583 log_error(aot, heap)(
1584 "Cannot archive the sub-graph referenced from %s object ("
1585 PTR_FORMAT ") size %zu, skipped.",
1586 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1587 if (level == 1) {
1588 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1589 // as the Java code will take care of initializing this field dynamically.
1590 return false;
1591 } else {
1592 // We don't know how to handle an object that has been archived, but some of its reachable
1593 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1594 // we have a real use case.
1595 MetaspaceShared::unrecoverable_writing_error();
1596 }
1597 }
1598 }
1599
1600 Klass *orig_k = orig_obj->klass();
1601 subgraph_info->add_subgraph_object_klass(orig_k);
1602
1603 {
1604 // Find all the oops that are referenced by orig_obj, push them onto the stack
1605 // so we can work on them next.
1606 ResourceMark rm;
1607 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1608 orig_obj->oop_iterate(&pusher);
1609 }
1610
1611 if (CDSConfig::is_initing_classes_at_dump_time()) {
1612 // The enum klasses are archived with aot-initialized mirror.
1613 // See AOTClassInitializer::can_archive_initialized_mirror().
1614 } else {
1615 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1616 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1617 }
1618 }
1619
1620 return true;
1621 }
1622
1623 //
1624 // Start from the given static field in a java mirror and archive the
1625 // complete sub-graph of java heap objects that are reached directly
1626 // or indirectly from the starting object by following references.
1627 // Sub-graph archiving restrictions (current):
1628 //
1629 // - All classes of objects in the archived sub-graph (including the
1630 // entry class) must be boot class only.
1631 // - No java.lang.Class instance (java mirror) can be included inside
1632 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1633 //
1634 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1635 //
1636 // 1) Java object sub-graph archiving starts from a given static field
1637 // within a Class instance (java mirror). If the static field is a
1638 // reference field and points to a non-null java object, proceed to
1639 // the next step.
1640 //
1641 // 2) Archives the referenced java object. If an archived copy of the
1642 // current object already exists, updates the pointer in the archived
1643 // copy of the referencing object to point to the current archived object.
1644 // Otherwise, proceed to the next step.
1645 //
1646 // 3) Follows all references within the current java object and recursively
1647 // archive the sub-graph of objects starting from each reference.
1648 //
1649 // 4) Updates the pointer in the archived copy of referencing object to
1650 // point to the current archived object.
1651 //
1652 // 5) The Klass of the current java object is added to the list of Klasses
1653 // for loading and initializing before any object in the archived graph can
1654 // be accessed at runtime.
1655 //
1656 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1657 const char* klass_name,
1658 int field_offset,
1659 const char* field_name) {
1660 assert(CDSConfig::is_dumping_heap(), "dump time only");
1661 assert(k->defined_by_boot_loader(), "must be boot class");
1662
1663 oop m = k->java_mirror();
1664
1665 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1666 oop f = m->obj_field(field_offset);
1667
1668 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1669
1670 if (!CompressedOops::is_null(f)) {
1671 if (log_is_enabled(Trace, aot, heap)) {
1672 LogTarget(Trace, aot, heap) log;
1673 LogStream out(log);
1674 f->print_on(&out);
1675 }
1676
1677 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1678 if (!success) {
1679 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1680 klass_name, field_name);
1681 } else {
1682 // Note: the field value is not preserved in the archived mirror.
1683 // Record the field as a new subGraph entry point. The recorded
1684 // information is restored from the archive at runtime.
1685 subgraph_info->add_subgraph_entry_field(field_offset, f);
1686 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1687 }
1688 } else {
1689 // The field contains null, we still need to record the entry point,
1690 // so it can be restored at runtime.
1691 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1692 }
1693 }
1694
1695 #ifndef PRODUCT
1696 class VerifySharedOopClosure: public BasicOopIterateClosure {
1697 public:
1698 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1699 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1700
1701 protected:
1702 template <class T> void do_oop_work(T *p) {
1703 oop obj = RawAccess<>::oop_load(p);
1704 if (!CompressedOops::is_null(obj)) {
1705 HeapShared::verify_reachable_objects_from(obj);
1706 }
1707 }
1708 };
1709
1710 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1711 assert(CDSConfig::is_dumping_heap(), "dump time only");
1712 assert(k->defined_by_boot_loader(), "must be boot class");
1713
1714 oop m = k->java_mirror();
1715 oop f = m->obj_field(field_offset);
1716 if (!CompressedOops::is_null(f)) {
1717 verify_subgraph_from(f);
1718 }
1719 }
1720
1721 void HeapShared::verify_subgraph_from(oop orig_obj) {
1722 if (!has_been_archived(orig_obj)) {
1723 // It's OK for the root of a subgraph to be not archived. See comments in
1724 // archive_reachable_objects_from().
1725 return;
1726 }
1727
1728 // Verify that all objects reachable from orig_obj are archived.
1729 init_seen_objects_table();
1730 verify_reachable_objects_from(orig_obj);
1731 delete_seen_objects_table();
1732 }
1733
1734 void HeapShared::verify_reachable_objects_from(oop obj) {
1735 _num_total_verifications ++;
1736 if (java_lang_Class::is_instance(obj)) {
1737 obj = scratch_java_mirror(obj);
1738 assert(obj != nullptr, "must be");
1739 }
1740 if (!has_been_seen_during_subgraph_recording(obj)) {
1741 set_has_been_seen_during_subgraph_recording(obj);
1742 assert(has_been_archived(obj), "must be");
1743 VerifySharedOopClosure walker;
1744 obj->oop_iterate(&walker);
1745 }
1746 }
1747 #endif
1748
1749 void HeapShared::check_special_subgraph_classes() {
1750 if (CDSConfig::is_initing_classes_at_dump_time()) {
1751 // We can have aot-initialized classes (such as Enums) that can reference objects
1752 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
1753 // aot-initialize classes that are "safe".
1754 //
1755 // TODO: we need an automatic tool that checks the safety of aot-initialized
1756 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
1757 return;
1758 } else {
1759 // In this case, the special subgraph should contain a few specific types
1760 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
1761 int num = klasses->length();
1762 for (int i = 0; i < num; i++) {
1763 Klass* subgraph_k = klasses->at(i);
1764 Symbol* name = subgraph_k->name();
1765 if (subgraph_k->is_instance_klass() &&
1766 name != vmSymbols::java_lang_Class() &&
1767 name != vmSymbols::java_lang_String() &&
1768 name != vmSymbols::java_lang_ArithmeticException() &&
1769 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
1770 name != vmSymbols::java_lang_ArrayStoreException() &&
1771 name != vmSymbols::java_lang_ClassCastException() &&
1772 name != vmSymbols::java_lang_InternalError() &&
1773 name != vmSymbols::java_lang_NullPointerException() &&
1774 name != vmSymbols::jdk_internal_vm_PreemptedException()) {
1775 ResourceMark rm;
1776 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
1777 }
1778 }
1779 }
1780 }
1781
1782 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
1783 HeapShared::PendingOop HeapShared::_object_being_archived;
1784 int HeapShared::_num_new_walked_objs;
1785 int HeapShared::_num_new_archived_objs;
1786 int HeapShared::_num_old_recorded_klasses;
1787
1788 int HeapShared::_num_total_subgraph_recordings = 0;
1789 int HeapShared::_num_total_walked_objs = 0;
1790 int HeapShared::_num_total_archived_objs = 0;
1791 int HeapShared::_num_total_recorded_klasses = 0;
1792 int HeapShared::_num_total_verifications = 0;
1793
1794 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1795 return _seen_objects_table->get(obj) != nullptr;
1796 }
1797
1798 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1799 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1800 _seen_objects_table->put_when_absent(obj, true);
1801 _seen_objects_table->maybe_grow();
1802 ++ _num_new_walked_objs;
1803 }
1804
1805 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1806 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1807 init_subgraph_info(k, is_full_module_graph);
1808 init_seen_objects_table();
1809 _num_new_walked_objs = 0;
1810 _num_new_archived_objs = 0;
1811 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1812 }
1813
1814 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1815 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1816 _num_old_recorded_klasses;
1817 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
1818 "walked %d objs, archived %d new objs, recorded %d classes",
1819 class_name, _num_new_walked_objs, _num_new_archived_objs,
1820 num_new_recorded_klasses);
1821
1822 delete_seen_objects_table();
1823
1824 _num_total_subgraph_recordings ++;
1825 _num_total_walked_objs += _num_new_walked_objs;
1826 _num_total_archived_objs += _num_new_archived_objs;
1827 _num_total_recorded_klasses += num_new_recorded_klasses;
1828 }
1829
1830 class ArchivableStaticFieldFinder: public FieldClosure {
1831 InstanceKlass* _ik;
1832 Symbol* _field_name;
1833 bool _found;
1834 int _offset;
1835 public:
1836 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1837 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1838
1839 virtual void do_field(fieldDescriptor* fd) {
1840 if (fd->name() == _field_name) {
1841 assert(!_found, "fields can never be overloaded");
1842 if (is_reference_type(fd->field_type())) {
1843 _found = true;
1844 _offset = fd->offset();
1845 }
1846 }
1847 }
1848 bool found() { return _found; }
1849 int offset() { return _offset; }
1850 };
1851
1852 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1853 TRAPS) {
1854 for (int i = 0; fields[i].valid(); i++) {
1855 ArchivableStaticFieldInfo* info = &fields[i];
1856 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1857 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1858 ResourceMark rm; // for stringStream::as_string() etc.
1859
1860 #ifndef PRODUCT
1861 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
1862 const char* test_class_name = ArchiveHeapTestClass;
1863 #else
1864 bool is_test_class = false;
1865 const char* test_class_name = ""; // avoid C++ printf checks warnings.
1866 #endif
1867
1868 if (is_test_class) {
1869 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
1870 }
1871
1872 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
1873 if (HAS_PENDING_EXCEPTION) {
1874 CLEAR_PENDING_EXCEPTION;
1875 stringStream st;
1876 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
1877 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1878 }
1879
1880 if (!k->is_instance_klass()) {
1881 stringStream st;
1882 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
1883 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1884 }
1885
1886 InstanceKlass* ik = InstanceKlass::cast(k);
1887 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
1888 "Only support boot classes");
1889
1890 if (is_test_class) {
1891 if (ik->module()->is_named()) {
1892 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
1893 // core-lib classes. You need to at least append to the bootclasspath.
1894 stringStream st;
1895 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
1896 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1897 }
1898
1899 if (ik->package() != nullptr) {
1900 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
1901 stringStream st;
1902 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
1903 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1904 }
1905 } else {
1906 if (ik->module()->name() != vmSymbols::java_base()) {
1907 // We don't want to deal with cases when a module is unavailable at runtime.
1908 // FUTURE -- load from archived heap only when module graph has not changed
1909 // between dump and runtime.
1910 stringStream st;
1911 st.print("%s is not in java.base module", info->klass_name);
1912 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1913 }
1914 }
1915
1916 if (is_test_class) {
1917 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
1918 }
1919 ik->initialize(CHECK);
1920
1921 ArchivableStaticFieldFinder finder(ik, field_name);
1922 ik->do_local_static_fields(&finder);
1923 if (!finder.found()) {
1924 stringStream st;
1925 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
1926 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1927 }
1928
1929 info->klass = ik;
1930 info->offset = finder.offset();
1931 }
1932 }
1933
1934 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1935 assert(CDSConfig::is_dumping_heap(), "must be");
1936 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
1937 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
1938 if (CDSConfig::is_dumping_full_module_graph()) {
1939 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
1940 }
1941 }
1942
1943 #ifndef PRODUCT
1944 void HeapShared::setup_test_class(const char* test_class_name) {
1945 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
1946 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
1947 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
1948 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
1949
1950 if (test_class_name != nullptr) {
1951 p[num_slots - 2].klass_name = test_class_name;
1952 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
1953 }
1954 }
1955
1956 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
1957 // during runtime. This may be called before the module system is initialized so
1958 // we cannot rely on InstanceKlass::module(), etc.
1959 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
1960 if (_test_class != nullptr) {
1961 if (ik == _test_class) {
1962 return true;
1963 }
1964 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
1965 if (klasses == nullptr) {
1966 return false;
1967 }
1968
1969 for (int i = 0; i < klasses->length(); i++) {
1970 Klass* k = klasses->at(i);
1971 if (k == ik) {
1972 Symbol* name;
1973 if (k->is_instance_klass()) {
1974 name = InstanceKlass::cast(k)->name();
1975 } else if (k->is_objArray_klass()) {
1976 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
1977 if (!bk->is_instance_klass()) {
1978 return false;
1979 }
1980 name = bk->name();
1981 } else {
1982 return false;
1983 }
1984
1985 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
1986 // to be:
1987 // (A) java.base classes (which must not be in the unnamed module)
1988 // (B) test classes which must be in the unnamed package of the unnamed module.
1989 // So if we see a '/' character in the class name, it must be in (A);
1990 // otherwise it must be in (B).
1991 if (name->index_of_at(0, "/", 1) >= 0) {
1992 return false; // (A)
1993 }
1994
1995 return true; // (B)
1996 }
1997 }
1998 }
1999
2000 return false;
2001 }
2002
2003 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2004 Klass* k = _test_class;
2005 if (k != nullptr && ArchiveHeapLoader::is_in_use()) {
2006 JavaThread* THREAD = current;
2007 ExceptionMark em(THREAD);
2008 const ArchivedKlassSubGraphInfoRecord* record =
2009 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2010
2011 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2012 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2013 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2014 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2015 if (record != nullptr) {
2016 init_archived_fields_for(k, record);
2017 }
2018 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2019 }
2020 }
2021 #endif
2022
2023 void HeapShared::init_for_dumping(TRAPS) {
2024 if (CDSConfig::is_dumping_heap()) {
2025 setup_test_class(ArchiveHeapTestClass);
2026 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
2027 init_subgraph_entry_fields(CHECK);
2028 }
2029 }
2030
2031 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2032 bool is_full_module_graph) {
2033 _num_total_subgraph_recordings = 0;
2034 _num_total_walked_objs = 0;
2035 _num_total_archived_objs = 0;
2036 _num_total_recorded_klasses = 0;
2037 _num_total_verifications = 0;
2038
2039 // For each class X that has one or more archived fields:
2040 // [1] Dump the subgraph of each archived field
2041 // [2] Create a list of all the class of the objects that can be reached
2042 // by any of these static fields.
2043 // At runtime, these classes are initialized before X's archived fields
2044 // are restored by HeapShared::initialize_from_archived_subgraph().
2045 for (int i = 0; fields[i].valid(); ) {
2046 ArchivableStaticFieldInfo* info = &fields[i];
2047 const char* klass_name = info->klass_name;
2048 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2049
2050 // If you have specified consecutive fields of the same klass in
2051 // fields[], these will be archived in the same
2052 // {start_recording_subgraph ... done_recording_subgraph} pass to
2053 // save time.
2054 for (; fields[i].valid(); i++) {
2055 ArchivableStaticFieldInfo* f = &fields[i];
2056 if (f->klass_name != klass_name) {
2057 break;
2058 }
2059
2060 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2061 f->offset, f->field_name);
2062 }
2063 done_recording_subgraph(info->klass, klass_name);
2064 }
2065
2066 log_info(aot, heap)("Archived subgraph records = %d",
2067 _num_total_subgraph_recordings);
2068 log_info(aot, heap)(" Walked %d objects", _num_total_walked_objs);
2069 log_info(aot, heap)(" Archived %d objects", _num_total_archived_objs);
2070 log_info(aot, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
2071
2072 #ifndef PRODUCT
2073 for (int i = 0; fields[i].valid(); i++) {
2074 ArchivableStaticFieldInfo* f = &fields[i];
2075 verify_subgraph_from_static_field(f->klass, f->offset);
2076 }
2077 log_info(aot, heap)(" Verified %d references", _num_total_verifications);
2078 #endif
2079 }
2080
2081 // Keep track of the contents of the archived interned string table. This table
2082 // is used only by CDSHeapVerifier.
2083 void HeapShared::add_to_dumped_interned_strings(oop string) {
2084 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
2085 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(string), "must be");
2086 bool created;
2087 _dumped_interned_strings->put_if_absent(string, true, &created);
2088 if (created) {
2089 // Prevent string deduplication from changing the value field to
2090 // something not in the archive.
2091 java_lang_String::set_deduplication_forbidden(string);
2092 _dumped_interned_strings->maybe_grow();
2093 }
2094 }
2095
2096 bool HeapShared::is_dumped_interned_string(oop o) {
2097 return _dumped_interned_strings->get(o) != nullptr;
2098 }
2099
2100 void HeapShared::debug_trace() {
2101 ResourceMark rm;
2102 oop referrer = _object_being_archived.referrer();
2103 if (referrer != nullptr) {
2104 LogStream ls(Log(aot, heap)::error());
2105 ls.print_cr("Reference trace");
2106 CDSHeapVerifier::trace_to_root(&ls, referrer);
2107 }
2108 }
2109
2110 #ifndef PRODUCT
2111 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2112 // region. This way we can quickly relocate all the pointers without using
2113 // BasicOopIterateClosure at runtime.
2114 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2115 void* _start;
2116 BitMap *_oopmap;
2117 int _num_total_oops;
2118 int _num_null_oops;
2119 public:
2120 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2121 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2122
2123 virtual void do_oop(narrowOop* p) {
2124 assert(UseCompressedOops, "sanity");
2125 _num_total_oops ++;
2126 narrowOop v = *p;
2127 if (!CompressedOops::is_null(v)) {
2128 size_t idx = p - (narrowOop*)_start;
2129 _oopmap->set_bit(idx);
2130 } else {
2131 _num_null_oops ++;
2132 }
2133 }
2134 virtual void do_oop(oop* p) {
2135 assert(!UseCompressedOops, "sanity");
2136 _num_total_oops ++;
2137 if ((*p) != nullptr) {
2138 size_t idx = p - (oop*)_start;
2139 _oopmap->set_bit(idx);
2140 } else {
2141 _num_null_oops ++;
2142 }
2143 }
2144 int num_total_oops() const { return _num_total_oops; }
2145 int num_null_oops() const { return _num_null_oops; }
2146 };
2147 #endif
2148
2149 void HeapShared::count_allocation(size_t size) {
2150 _total_obj_count ++;
2151 _total_obj_size += size;
2152 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2153 if (size <= (size_t(1) << i)) {
2154 _alloc_count[i] ++;
2155 _alloc_size[i] += size;
2156 return;
2157 }
2158 }
2159 }
2160
2161 static double avg_size(size_t size, size_t count) {
2162 double avg = 0;
2163 if (count > 0) {
2164 avg = double(size * HeapWordSize) / double(count);
2165 }
2166 return avg;
2167 }
2168
2169 void HeapShared::print_stats() {
2170 size_t huge_count = _total_obj_count;
2171 size_t huge_size = _total_obj_size;
2172
2173 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2174 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2175 size_t count = _alloc_count[i];
2176 size_t size = _alloc_size[i];
2177 log_info(aot, heap)("%8zu objects are <= %-6zu"
2178 " bytes (total %8zu bytes, avg %8.1f bytes)",
2179 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2180 huge_count -= count;
2181 huge_size -= size;
2182 }
2183
2184 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2185 ", avg %8.1f bytes)",
2186 huge_count, huge_size * HeapWordSize,
2187 avg_size(huge_size, huge_count));
2188 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2189 ", avg %8.1f bytes)",
2190 _total_obj_count, _total_obj_size * HeapWordSize,
2191 avg_size(_total_obj_size, _total_obj_count));
2192 }
2193
2194 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2195 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2196 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2197 if (k == nullptr) {
2198 return false;
2199 } else {
2200 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2201 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2202 fieldDescriptor fd;
2203 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2204 oop m = k->java_mirror();
2205 oop f = m->obj_field(fd.offset());
2206 if (CompressedOops::is_null(f)) {
2207 return false;
2208 }
2209 } else {
2210 return false;
2211 }
2212 }
2213 return true;
2214 }
2215
2216 #endif // INCLUDE_CDS_JAVA_HEAP