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