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(_dumped_interned_strings);
626 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, shared_strings_array);
627 // We must succeed because:
628 // - _dumped_interned_strings do not contain any large strings.
629 // - StringTable::init_shared_table() doesn't create any large arrays.
630 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
631 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
632 }
633
634 int HeapShared::archive_exception_instance(oop exception) {
635 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
636 assert(success, "sanity");
637 return append_root(exception);
638 }
639
640 void HeapShared::mark_native_pointers(oop orig_obj) {
641 if (java_lang_Class::is_instance(orig_obj)) {
642 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::klass_offset());
643 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::array_klass_offset());
644 } else if (java_lang_invoke_ResolvedMethodName::is_instance(orig_obj)) {
645 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_invoke_ResolvedMethodName::vmtarget_offset());
646 }
647 }
648
649 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
650 CachedOopInfo* info = archived_object_cache()->get(src_obj);
651 assert(info != nullptr, "must be");
652 has_oop_pointers = info->has_oop_pointers();
653 has_native_pointers = info->has_native_pointers();
654 }
655
656 void HeapShared::set_has_native_pointers(oop src_obj) {
657 CachedOopInfo* info = archived_object_cache()->get(src_obj);
658 assert(info != nullptr, "must be");
659 info->set_has_native_pointers();
660 }
661
662 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
663 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
664 void HeapShared::start_scanning_for_oops() {
665 {
666 NoSafepointVerifier nsv;
667
668 // The special subgraph doesn't belong to any class. We use Object_klass() here just
669 // for convenience.
670 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
671
672 // Cache for recording where the archived objects are copied to
673 create_archived_object_cache();
674
675 if (UseCompressedOops || UseG1GC) {
676 log_info(cds)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
677 UseCompressedOops ? p2i(CompressedOops::begin()) :
678 p2i((address)G1CollectedHeap::heap()->reserved().start()),
679 UseCompressedOops ? p2i(CompressedOops::end()) :
680 p2i((address)G1CollectedHeap::heap()->reserved().end()));
681 }
682
683 archive_subgraphs();
684 }
685
686 init_seen_objects_table();
687 Universe::archive_exception_instances();
688 }
689
690 void HeapShared::end_scanning_for_oops() {
691 archive_strings();
692 delete_seen_objects_table();
693 }
694
695 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
696 {
697 NoSafepointVerifier nsv;
698 CDSHeapVerifier::verify();
699 check_special_subgraph_classes();
700 }
701
702 StringTable::write_shared_table(_dumped_interned_strings);
703 ArchiveHeapWriter::write(_pending_roots, heap_info);
704
705 ArchiveBuilder::OtherROAllocMark mark;
706 write_subgraph_info_table();
707 }
708
709 void HeapShared::scan_java_mirror(oop orig_mirror) {
710 oop m = scratch_java_mirror(orig_mirror);
711 if (m != nullptr) { // nullptr if for custom class loader
712 copy_java_mirror_hashcode(orig_mirror, m);
713 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
714 assert(success, "sanity");
715 }
716 }
717
718 void HeapShared::scan_java_class(Klass* orig_k) {
719 scan_java_mirror(orig_k->java_mirror());
720
721 if (orig_k->is_instance_klass()) {
722 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
723 orig_ik->constants()->prepare_resolved_references_for_archiving();
724 objArrayOop rr = get_archived_resolved_references(orig_ik);
725 if (rr != nullptr) {
726 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
727 assert(success, "must be");
728 }
729
730 orig_ik->constants()->add_dumped_interned_strings();
731 }
732 }
733
734 void HeapShared::archive_subgraphs() {
735 assert(CDSConfig::is_dumping_heap(), "must be");
736
737 archive_object_subgraphs(archive_subgraph_entry_fields,
738 false /* is_full_module_graph */);
739
740 if (CDSConfig::is_dumping_full_module_graph()) {
741 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
742 true /* is_full_module_graph */);
743 Modules::verify_archived_modules();
744 }
745 }
746
747 //
748 // Subgraph archiving support
749 //
750 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
751 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
752
753 // Get the subgraph_info for Klass k. A new subgraph_info is created if
754 // there is no existing one for k. The subgraph_info records the "buffered"
755 // address of the class.
756 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
757 assert(CDSConfig::is_dumping_heap(), "dump time only");
758 bool created;
759 KlassSubGraphInfo* info =
760 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
761 &created);
762 assert(created, "must not initialize twice");
763 return info;
764 }
765
766 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
767 assert(CDSConfig::is_dumping_heap(), "dump time only");
768 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
769 assert(info != nullptr, "must have been initialized");
770 return info;
771 }
772
773 // Add an entry field to the current KlassSubGraphInfo.
774 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
775 assert(CDSConfig::is_dumping_heap(), "dump time only");
776 if (_subgraph_entry_fields == nullptr) {
777 _subgraph_entry_fields =
778 new (mtClass) GrowableArray<int>(10, mtClass);
779 }
780 _subgraph_entry_fields->append(static_field_offset);
781 _subgraph_entry_fields->append(HeapShared::append_root(v));
782 }
783
784 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
785 // Only objects of boot classes can be included in sub-graph.
786 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
787 assert(CDSConfig::is_dumping_heap(), "dump time only");
788
789 if (_subgraph_object_klasses == nullptr) {
790 _subgraph_object_klasses =
791 new (mtClass) GrowableArray<Klass*>(50, mtClass);
792 }
793
794 if (_k == orig_k) {
795 // Don't add the Klass containing the sub-graph to it's own klass
796 // initialization list.
797 return;
798 }
799
800 if (orig_k->is_instance_klass()) {
801 #ifdef ASSERT
802 InstanceKlass* ik = InstanceKlass::cast(orig_k);
803 if (CDSConfig::is_dumping_method_handles()) {
804 // -XX:AOTInitTestClass must be used carefully in regression tests to
805 // include only classes that are safe to aot-initialize.
806 assert(ik->class_loader() == nullptr ||
807 HeapShared::is_lambda_proxy_klass(ik) ||
808 AOTClassInitializer::has_test_class(),
809 "we can archive only instances of boot classes or lambda proxy classes");
810 } else {
811 assert(ik->class_loader() == nullptr, "must be boot class");
812 }
813 #endif
814 // vmClasses::xxx_klass() are not updated, need to check
815 // the original Klass*
816 if (orig_k == vmClasses::String_klass() ||
817 orig_k == vmClasses::Object_klass()) {
818 // Initialized early during VM initialization. No need to be added
819 // to the sub-graph object class list.
820 return;
821 }
822 check_allowed_klass(InstanceKlass::cast(orig_k));
823 } else if (orig_k->is_objArray_klass()) {
824 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
825 if (abk->is_instance_klass()) {
826 assert(InstanceKlass::cast(abk)->is_shared_boot_class(),
827 "must be boot class");
828 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
829 }
830 if (orig_k == Universe::objectArrayKlass()) {
831 // Initialized early during Universe::genesis. No need to be added
832 // to the list.
833 return;
834 }
835 } else {
836 assert(orig_k->is_typeArray_klass(), "must be");
837 // Primitive type arrays are created early during Universe::genesis.
838 return;
839 }
840
841 if (log_is_enabled(Debug, cds, heap)) {
842 if (!_subgraph_object_klasses->contains(orig_k)) {
843 ResourceMark rm;
844 log_debug(cds, heap)("Adding klass %s", orig_k->external_name());
845 }
846 }
847
848 _subgraph_object_klasses->append_if_missing(orig_k);
849 _has_non_early_klasses |= is_non_early_klass(orig_k);
850 }
851
852 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
853 #ifndef PRODUCT
854 if (AOTClassInitializer::has_test_class()) {
855 // The tests can cache arbitrary types of objects.
856 return;
857 }
858 #endif
859
860 if (ik->module()->name() == vmSymbols::java_base()) {
861 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
862 return;
863 }
864
865 const char* lambda_msg = "";
866 if (CDSConfig::is_dumping_method_handles()) {
867 lambda_msg = ", or a lambda proxy class";
868 if (HeapShared::is_lambda_proxy_klass(ik) &&
869 (ik->class_loader() == nullptr ||
870 ik->class_loader() == SystemDictionary::java_platform_loader() ||
871 ik->class_loader() == SystemDictionary::java_system_loader())) {
872 return;
873 }
874 }
875
876 #ifndef PRODUCT
877 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
878 // This class is loaded by ArchiveHeapTestClass
879 return;
880 }
881 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
882 #else
883 const char* testcls_msg = "";
884 #endif
885
886 ResourceMark rm;
887 log_error(cds, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
888 ik->external_name(), lambda_msg, testcls_msg);
889 MetaspaceShared::unrecoverable_writing_error();
890 }
891
892 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
893 if (k->is_objArray_klass()) {
894 k = ObjArrayKlass::cast(k)->bottom_klass();
895 }
896 if (k->is_instance_klass()) {
897 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
898 ResourceMark rm;
899 log_info(cds, heap)("non-early: %s", k->external_name());
900 return true;
901 } else {
902 return false;
903 }
904 } else {
905 return false;
906 }
907 }
908
909 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
910 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
911 _k = ArchiveBuilder::get_buffered_klass(info->klass());
912 _entry_field_records = nullptr;
913 _subgraph_object_klasses = nullptr;
914 _is_full_module_graph = info->is_full_module_graph();
915
916 if (_is_full_module_graph) {
917 // Consider all classes referenced by the full module graph as early -- we will be
918 // allocating objects of these classes during JVMTI early phase, so they cannot
919 // be processed by (non-early) JVMTI ClassFileLoadHook
920 _has_non_early_klasses = false;
921 } else {
922 _has_non_early_klasses = info->has_non_early_klasses();
923 }
924
925 if (_has_non_early_klasses) {
926 ResourceMark rm;
927 log_info(cds, heap)(
928 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
929 _k->external_name());
930 }
931
932 // populate the entry fields
933 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
934 if (entry_fields != nullptr) {
935 int num_entry_fields = entry_fields->length();
936 assert(num_entry_fields % 2 == 0, "sanity");
937 _entry_field_records =
938 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
939 for (int i = 0 ; i < num_entry_fields; i++) {
940 _entry_field_records->at_put(i, entry_fields->at(i));
941 }
942 }
943
944 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
945 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
946 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
947 if (recorded_klasses != nullptr) {
948 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
949 // programmatically loading a subgraph, we only need to explicitly initialize the classes
950 // that are not aot-inited.
951 int num_to_copy = 0;
952 for (int i = 0; i < recorded_klasses->length(); i++) {
953 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
954 if (!subgraph_k->has_aot_initialized_mirror()) {
955 num_to_copy ++;
956 }
957 }
958
959 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
960 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
961 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
962 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
963 if (subgraph_k->has_aot_initialized_mirror()) {
964 continue;
965 }
966 if (log_is_enabled(Info, cds, heap)) {
967 ResourceMark rm;
968 const char* owner_name = is_special ? "<special>" : _k->external_name();
969 if (subgraph_k->is_instance_klass()) {
970 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
971 }
972 log_info(cds, heap)(
973 "Archived object klass %s (%2d) => %s",
974 owner_name, n, subgraph_k->external_name());
975 }
976 _subgraph_object_klasses->at_put(n, subgraph_k);
977 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
978 n++;
979 }
980 }
981
982 ArchivePtrMarker::mark_pointer(&_k);
983 ArchivePtrMarker::mark_pointer(&_entry_field_records);
984 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
985 }
986
987 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
988 CompactHashtableWriter* _writer;
989 public:
990 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
991
992 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
993 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
994 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
995 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
996 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
997 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
998 _writer->add(hash, delta);
999 }
1000 return true; // keep on iterating
1001 }
1002 };
1003
1004 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
1005 ArchivedKlassSubGraphInfoRecord* record =
1006 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
1007 record->init(info);
1008 if (info == _dump_time_special_subgraph) {
1009 _run_time_special_subgraph = record;
1010 }
1011 return record;
1012 }
1013
1014 // Build the records of archived subgraph infos, which include:
1015 // - Entry points to all subgraphs from the containing class mirror. The entry
1016 // points are static fields in the mirror. For each entry point, the field
1017 // offset, and value are recorded in the sub-graph
1018 // info. The value is stored back to the corresponding field at runtime.
1019 // - A list of klasses that need to be loaded/initialized before archived
1020 // java object sub-graph can be accessed at runtime.
1021 void HeapShared::write_subgraph_info_table() {
1022 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1023 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1024 CompactHashtableStats stats;
1025
1026 _run_time_subgraph_info_table.reset();
1027
1028 CompactHashtableWriter writer(d_table->_count, &stats);
1029 CopyKlassSubGraphInfoToArchive copy(&writer);
1030 d_table->iterate(©);
1031 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1032
1033 #ifndef PRODUCT
1034 if (ArchiveHeapTestClass != nullptr) {
1035 size_t len = strlen(ArchiveHeapTestClass) + 1;
1036 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1037 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1038 _archived_ArchiveHeapTestClass = array;
1039 }
1040 #endif
1041 if (log_is_enabled(Info, cds, heap)) {
1042 print_stats();
1043 }
1044 }
1045
1046 void HeapShared::add_root_segment(objArrayOop segment_oop) {
1047 assert(segment_oop != nullptr, "must be");
1048 assert(ArchiveHeapLoader::is_in_use(), "must be");
1049 if (_root_segments == nullptr) {
1050 _root_segments = new GrowableArrayCHeap<OopHandle, mtClassShared>(10);
1051 }
1052 _root_segments->push(OopHandle(Universe::vm_global(), segment_oop));
1053 }
1054
1055 void HeapShared::init_root_segment_sizes(int max_size_elems) {
1056 _root_segment_max_size_elems = max_size_elems;
1057 }
1058
1059 void HeapShared::serialize_tables(SerializeClosure* soc) {
1060
1061 #ifndef PRODUCT
1062 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1063 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1064 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1065 setup_test_class(_test_class_name);
1066 }
1067 #endif
1068
1069 _run_time_subgraph_info_table.serialize_header(soc);
1070 soc->do_ptr(&_run_time_special_subgraph);
1071 }
1072
1073 static void verify_the_heap(Klass* k, const char* which) {
1074 if (VerifyArchivedFields > 0) {
1075 ResourceMark rm;
1076 log_info(cds, heap)("Verify heap %s initializing static field(s) in %s",
1077 which, k->external_name());
1078
1079 VM_Verify verify_op;
1080 VMThread::execute(&verify_op);
1081
1082 if (VerifyArchivedFields > 1 && is_init_completed()) {
1083 // At this time, the oop->klass() of some archived objects in the heap may not
1084 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1085 // have enough information (object size, oop maps, etc) so that a GC can be safely
1086 // performed.
1087 //
1088 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1089 // to check for GC safety.
1090 log_info(cds, heap)("Trigger GC %s initializing static field(s) in %s",
1091 which, k->external_name());
1092 FlagSetting fs1(VerifyBeforeGC, true);
1093 FlagSetting fs2(VerifyDuringGC, true);
1094 FlagSetting fs3(VerifyAfterGC, true);
1095 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1096 }
1097 }
1098 }
1099
1100 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1101 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1102 //
1103 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1104 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1105 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1106 void HeapShared::resolve_classes(JavaThread* current) {
1107 assert(CDSConfig::is_using_archive(), "runtime only!");
1108 if (!ArchiveHeapLoader::is_in_use()) {
1109 return; // nothing to do
1110 }
1111 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1112 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1113 }
1114
1115 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1116 for (int i = 0; fields[i].valid(); i++) {
1117 ArchivableStaticFieldInfo* info = &fields[i];
1118 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1119 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1120 assert(k != nullptr && k->is_shared_boot_class(), "sanity");
1121 resolve_classes_for_subgraph_of(current, k);
1122 }
1123 }
1124
1125 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1126 JavaThread* THREAD = current;
1127 ExceptionMark em(THREAD);
1128 const ArchivedKlassSubGraphInfoRecord* record =
1129 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1130 if (HAS_PENDING_EXCEPTION) {
1131 CLEAR_PENDING_EXCEPTION;
1132 }
1133 if (record == nullptr) {
1134 clear_archived_roots_of(k);
1135 }
1136 }
1137
1138 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1139 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1140 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1141 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1142 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1143 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1144 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1145 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1146 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1147 }
1148 }
1149
1150 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1151 // - interned strings
1152 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1153 // - ConstantPool::resolved_references()
1154 // - Universe::<xxx>_exception_instance()
1155 //
1156 // For example, if this enum class is initialized at AOT cache assembly time:
1157 //
1158 // enum Fruit {
1159 // APPLE, ORANGE, BANANA;
1160 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1161 // }
1162 //
1163 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1164 // should be initialized before any Java code can access the Fruit class. Note that
1165 // HashSet itself doesn't necessary need to be an aot-initialized class.
1166 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1167 if (!ArchiveHeapLoader::is_in_use()) {
1168 return;
1169 }
1170
1171 assert( _run_time_special_subgraph != nullptr, "must be");
1172 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1173 if (klasses != nullptr) {
1174 for (int pass = 0; pass < 2; pass ++) {
1175 for (int i = 0; i < klasses->length(); i++) {
1176 Klass* k = klasses->at(i);
1177 if (k->class_loader_data() == nullptr) {
1178 // This class is not yet loaded. We will initialize it in a later phase.
1179 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1180 // but k is part of AOTLinkedClassCategory::BOOT2.
1181 continue;
1182 }
1183 if (k->class_loader() == class_loader()) {
1184 if (pass == 0) {
1185 if (k->is_instance_klass()) {
1186 InstanceKlass::cast(k)->link_class(CHECK);
1187 }
1188 } else {
1189 resolve_or_init(k, /*do_init*/true, CHECK);
1190 }
1191 }
1192 }
1193 }
1194 }
1195 }
1196
1197 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1198 JavaThread* THREAD = current;
1199 if (!ArchiveHeapLoader::is_in_use()) {
1200 return; // nothing to do
1201 }
1202
1203 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1204 !CDSConfig::is_using_optimized_module_handling() &&
1205 // archive was created with --module-path
1206 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1207 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1208 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1209 log_info(cds, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1210 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1211 AOTClassLocationConfig::runtime()->num_module_paths());
1212 return;
1213 }
1214
1215 ExceptionMark em(THREAD);
1216 const ArchivedKlassSubGraphInfoRecord* record =
1217 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1218
1219 if (HAS_PENDING_EXCEPTION) {
1220 CLEAR_PENDING_EXCEPTION;
1221 // None of the field value will be set if there was an exception when initializing the classes.
1222 // The java code will not see any of the archived objects in the
1223 // subgraphs referenced from k in this case.
1224 return;
1225 }
1226
1227 if (record != nullptr) {
1228 init_archived_fields_for(k, record);
1229 }
1230 }
1231
1232 const ArchivedKlassSubGraphInfoRecord*
1233 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1234 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1235
1236 if (!k->is_shared()) {
1237 return nullptr;
1238 }
1239 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1240 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1241
1242 #ifndef PRODUCT
1243 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1244 _test_class = k;
1245 _test_class_record = record;
1246 }
1247 #endif
1248
1249 // Initialize from archived data. Currently this is done only
1250 // during VM initialization time. No lock is needed.
1251 if (record == nullptr) {
1252 if (log_is_enabled(Info, cds, heap)) {
1253 ResourceMark rm(THREAD);
1254 log_info(cds, heap)("subgraph %s is not recorded",
1255 k->external_name());
1256 }
1257 return nullptr;
1258 } else {
1259 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1260 if (log_is_enabled(Info, cds, heap)) {
1261 ResourceMark rm(THREAD);
1262 log_info(cds, heap)("subgraph %s cannot be used because full module graph is disabled",
1263 k->external_name());
1264 }
1265 return nullptr;
1266 }
1267
1268 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1269 if (log_is_enabled(Info, cds, heap)) {
1270 ResourceMark rm(THREAD);
1271 log_info(cds, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1272 k->external_name());
1273 }
1274 return nullptr;
1275 }
1276
1277 if (log_is_enabled(Info, cds, heap)) {
1278 ResourceMark rm;
1279 log_info(cds, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1280 }
1281
1282 resolve_or_init(k, do_init, CHECK_NULL);
1283
1284 // Load/link/initialize the klasses of the objects in the subgraph.
1285 // nullptr class loader is used.
1286 Array<Klass*>* klasses = record->subgraph_object_klasses();
1287 if (klasses != nullptr) {
1288 for (int i = 0; i < klasses->length(); i++) {
1289 Klass* klass = klasses->at(i);
1290 if (!klass->is_shared()) {
1291 return nullptr;
1292 }
1293 resolve_or_init(klass, do_init, CHECK_NULL);
1294 }
1295 }
1296 }
1297
1298 return record;
1299 }
1300
1301 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1302 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1303 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1304 if (k == nullptr) {
1305 return;
1306 }
1307 assert(k->is_shared_boot_class(), "sanity");
1308 resolve_or_init(k, false, CHECK);
1309 if (do_init) {
1310 resolve_or_init(k, true, CHECK);
1311 }
1312 }
1313
1314 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1315 if (!do_init) {
1316 if (k->class_loader_data() == nullptr) {
1317 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1318 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1319 }
1320 } else {
1321 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1322 if (k->is_instance_klass()) {
1323 InstanceKlass* ik = InstanceKlass::cast(k);
1324 ik->initialize(CHECK);
1325 } else if (k->is_objArray_klass()) {
1326 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1327 oak->initialize(CHECK);
1328 }
1329 }
1330 }
1331
1332 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1333 verify_the_heap(k, "before");
1334
1335 // Load the subgraph entry fields from the record and store them back to
1336 // the corresponding fields within the mirror.
1337 oop m = k->java_mirror();
1338 Array<int>* entry_field_records = record->entry_field_records();
1339 if (entry_field_records != nullptr) {
1340 int efr_len = entry_field_records->length();
1341 assert(efr_len % 2 == 0, "sanity");
1342 for (int i = 0; i < efr_len; i += 2) {
1343 int field_offset = entry_field_records->at(i);
1344 int root_index = entry_field_records->at(i+1);
1345 oop v = get_root(root_index, /*clear=*/true);
1346 if (k->has_aot_initialized_mirror()) {
1347 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1348 } else {
1349 m->obj_field_put(field_offset, v);
1350 }
1351 log_debug(cds, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1352 }
1353
1354 // Done. Java code can see the archived sub-graphs referenced from k's
1355 // mirror after this point.
1356 if (log_is_enabled(Info, cds, heap)) {
1357 ResourceMark rm;
1358 log_info(cds, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1359 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1360 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1361 }
1362 }
1363
1364 verify_the_heap(k, "after ");
1365 }
1366
1367 void HeapShared::clear_archived_roots_of(Klass* k) {
1368 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1369 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1370 if (record != nullptr) {
1371 Array<int>* entry_field_records = record->entry_field_records();
1372 if (entry_field_records != nullptr) {
1373 int efr_len = entry_field_records->length();
1374 assert(efr_len % 2 == 0, "sanity");
1375 for (int i = 0; i < efr_len; i += 2) {
1376 int root_index = entry_field_records->at(i+1);
1377 clear_root(root_index);
1378 }
1379 }
1380 }
1381 }
1382
1383 // Push all oop fields (or oop array elemenets in case of an objArray) in
1384 // _referencing_obj onto the _stack.
1385 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1386 PendingOopStack* _stack;
1387 GrowableArray<oop> _found_oop_fields;
1388 int _level;
1389 bool _record_klasses_only;
1390 KlassSubGraphInfo* _subgraph_info;
1391 oop _referencing_obj;
1392 bool _is_java_lang_ref;
1393 public:
1394 OopFieldPusher(PendingOopStack* stack,
1395 int level,
1396 bool record_klasses_only,
1397 KlassSubGraphInfo* subgraph_info,
1398 oop orig) :
1399 _stack(stack),
1400 _found_oop_fields(),
1401 _level(level),
1402 _record_klasses_only(record_klasses_only),
1403 _subgraph_info(subgraph_info),
1404 _referencing_obj(orig) {
1405 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1406 }
1407 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1408 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1409
1410 ~OopFieldPusher() {
1411 while (_found_oop_fields.length() > 0) {
1412 // This produces the exact same traversal order as the previous version
1413 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1414 // walking the oop fields in _referencing_obj by ascending field offsets.
1415 oop obj = _found_oop_fields.pop();
1416 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1417 }
1418 }
1419
1420 protected:
1421 template <class T> void do_oop_work(T *p) {
1422 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1423 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1424 if (!CompressedOops::is_null(obj)) {
1425 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1426 // Do not follow these fields. They will be cleared to null.
1427 return;
1428 }
1429
1430 if (!_record_klasses_only && log_is_enabled(Debug, cds, heap)) {
1431 ResourceMark rm;
1432 log_debug(cds, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1433 _referencing_obj->klass()->external_name(), field_offset,
1434 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1435 if (log_is_enabled(Trace, cds, heap)) {
1436 LogTarget(Trace, cds, heap) log;
1437 LogStream out(log);
1438 obj->print_on(&out);
1439 }
1440 }
1441
1442 _found_oop_fields.push(obj);
1443 }
1444 }
1445
1446 public:
1447 oop referencing_obj() { return _referencing_obj; }
1448 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1449 };
1450
1451 // Checks if an oop has any non-null oop fields
1452 class PointsToOopsChecker : public BasicOopIterateClosure {
1453 bool _result;
1454
1455 template <class T> void check(T *p) {
1456 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1457 }
1458
1459 public:
1460 PointsToOopsChecker() : _result(false) {}
1461 void do_oop(narrowOop *p) { check(p); }
1462 void do_oop( oop *p) { check(p); }
1463 bool result() { return _result; }
1464 };
1465
1466 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1467 PointsToOopsChecker points_to_oops_checker;
1468 obj->oop_iterate(&points_to_oops_checker);
1469 return CachedOopInfo(referrer, points_to_oops_checker.result());
1470 }
1471
1472 void HeapShared::init_box_classes(TRAPS) {
1473 if (ArchiveHeapLoader::is_in_use()) {
1474 vmClasses::Boolean_klass()->initialize(CHECK);
1475 vmClasses::Character_klass()->initialize(CHECK);
1476 vmClasses::Float_klass()->initialize(CHECK);
1477 vmClasses::Double_klass()->initialize(CHECK);
1478 vmClasses::Byte_klass()->initialize(CHECK);
1479 vmClasses::Short_klass()->initialize(CHECK);
1480 vmClasses::Integer_klass()->initialize(CHECK);
1481 vmClasses::Long_klass()->initialize(CHECK);
1482 vmClasses::Void_klass()->initialize(CHECK);
1483 }
1484 }
1485
1486 // (1) If orig_obj has not been archived yet, archive it.
1487 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1488 // trace all objects that are reachable from it, and make sure these objects are archived.
1489 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1490 // were already archived when this function is called)
1491 bool HeapShared::archive_reachable_objects_from(int level,
1492 KlassSubGraphInfo* subgraph_info,
1493 oop orig_obj) {
1494 assert(orig_obj != nullptr, "must be");
1495 PendingOopStack stack;
1496 stack.push(PendingOop(orig_obj, nullptr, level));
1497
1498 while (stack.length() > 0) {
1499 PendingOop po = stack.pop();
1500 _object_being_archived = po;
1501 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1502 _object_being_archived = PendingOop();
1503
1504 if (!status) {
1505 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1506 // as the Java code will take care of initializing this field dynamically.
1507 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1508 return false;
1509 }
1510 }
1511
1512 return true;
1513 }
1514
1515 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1516 oop orig_obj, oop referrer) {
1517 assert(orig_obj != nullptr, "must be");
1518 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1519 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1520 // If you get an error here, you probably made a change in the JDK library that has added
1521 // these objects that are referenced (directly or indirectly) by static fields.
1522 ResourceMark rm;
1523 log_error(cds, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1524 debug_trace();
1525 MetaspaceShared::unrecoverable_writing_error();
1526 }
1527
1528 if (log_is_enabled(Debug, cds, heap) && java_lang_Class::is_instance(orig_obj)) {
1529 ResourceMark rm;
1530 LogTarget(Debug, cds, heap) log;
1531 LogStream out(log);
1532 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1533 Klass* k = java_lang_Class::as_Klass(orig_obj);
1534 if (k != nullptr) {
1535 out.print("%s", k->external_name());
1536 } else {
1537 out.print("primitive");
1538 }
1539 out.print_cr("; scratch mirror = " PTR_FORMAT,
1540 p2i(scratch_java_mirror(orig_obj)));
1541 }
1542
1543 if (CDSConfig::is_initing_classes_at_dump_time()) {
1544 if (java_lang_Class::is_instance(orig_obj)) {
1545 orig_obj = scratch_java_mirror(orig_obj);
1546 assert(orig_obj != nullptr, "must be archived");
1547 }
1548 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1549 // Without CDSConfig::is_initing_classes_at_dump_time(), we only allow archived objects to
1550 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1551 // very early by HeapShared::init_box_classes().
1552 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1553 || java_lang_Class::is_primitive(orig_obj)
1554 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1555 || orig_obj == vmClasses::Character_klass()->java_mirror()
1556 || orig_obj == vmClasses::Float_klass()->java_mirror()
1557 || orig_obj == vmClasses::Double_klass()->java_mirror()
1558 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1559 || orig_obj == vmClasses::Short_klass()->java_mirror()
1560 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1561 || orig_obj == vmClasses::Long_klass()->java_mirror()
1562 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1563 orig_obj = scratch_java_mirror(orig_obj);
1564 assert(orig_obj != nullptr, "must be archived");
1565 } else {
1566 // If you get an error here, you probably made a change in the JDK library that has added a Class
1567 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1568 // defined at the top of this file.
1569 log_error(cds, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1570 debug_trace();
1571 MetaspaceShared::unrecoverable_writing_error();
1572 }
1573 }
1574
1575 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1576 // orig_obj has already been archived and traced. Nothing more to do.
1577 return true;
1578 } else {
1579 set_has_been_seen_during_subgraph_recording(orig_obj);
1580 }
1581
1582 bool already_archived = has_been_archived(orig_obj);
1583 bool record_klasses_only = already_archived;
1584 if (!already_archived) {
1585 ++_num_new_archived_objs;
1586 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1587 // Skip archiving the sub-graph referenced from the current entry field.
1588 ResourceMark rm;
1589 log_error(cds, heap)(
1590 "Cannot archive the sub-graph referenced from %s object ("
1591 PTR_FORMAT ") size %zu, skipped.",
1592 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1593 if (level == 1) {
1594 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1595 // as the Java code will take care of initializing this field dynamically.
1596 return false;
1597 } else {
1598 // We don't know how to handle an object that has been archived, but some of its reachable
1599 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1600 // we have a real use case.
1601 MetaspaceShared::unrecoverable_writing_error();
1602 }
1603 }
1604 }
1605
1606 Klass *orig_k = orig_obj->klass();
1607 subgraph_info->add_subgraph_object_klass(orig_k);
1608
1609 {
1610 // Find all the oops that are referenced by orig_obj, push them onto the stack
1611 // so we can work on them next.
1612 ResourceMark rm;
1613 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1614 orig_obj->oop_iterate(&pusher);
1615 }
1616
1617 if (CDSConfig::is_initing_classes_at_dump_time()) {
1618 // The enum klasses are archived with aot-initialized mirror.
1619 // See AOTClassInitializer::can_archive_initialized_mirror().
1620 } else {
1621 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1622 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1623 }
1624 }
1625
1626 return true;
1627 }
1628
1629 //
1630 // Start from the given static field in a java mirror and archive the
1631 // complete sub-graph of java heap objects that are reached directly
1632 // or indirectly from the starting object by following references.
1633 // Sub-graph archiving restrictions (current):
1634 //
1635 // - All classes of objects in the archived sub-graph (including the
1636 // entry class) must be boot class only.
1637 // - No java.lang.Class instance (java mirror) can be included inside
1638 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1639 //
1640 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1641 //
1642 // 1) Java object sub-graph archiving starts from a given static field
1643 // within a Class instance (java mirror). If the static field is a
1644 // reference field and points to a non-null java object, proceed to
1645 // the next step.
1646 //
1647 // 2) Archives the referenced java object. If an archived copy of the
1648 // current object already exists, updates the pointer in the archived
1649 // copy of the referencing object to point to the current archived object.
1650 // Otherwise, proceed to the next step.
1651 //
1652 // 3) Follows all references within the current java object and recursively
1653 // archive the sub-graph of objects starting from each reference.
1654 //
1655 // 4) Updates the pointer in the archived copy of referencing object to
1656 // point to the current archived object.
1657 //
1658 // 5) The Klass of the current java object is added to the list of Klasses
1659 // for loading and initializing before any object in the archived graph can
1660 // be accessed at runtime.
1661 //
1662 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1663 const char* klass_name,
1664 int field_offset,
1665 const char* field_name) {
1666 assert(CDSConfig::is_dumping_heap(), "dump time only");
1667 assert(k->is_shared_boot_class(), "must be boot class");
1668
1669 oop m = k->java_mirror();
1670
1671 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1672 oop f = m->obj_field(field_offset);
1673
1674 log_debug(cds, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1675
1676 if (!CompressedOops::is_null(f)) {
1677 if (log_is_enabled(Trace, cds, heap)) {
1678 LogTarget(Trace, cds, heap) log;
1679 LogStream out(log);
1680 f->print_on(&out);
1681 }
1682
1683 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1684 if (!success) {
1685 log_error(cds, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1686 klass_name, field_name);
1687 } else {
1688 // Note: the field value is not preserved in the archived mirror.
1689 // Record the field as a new subGraph entry point. The recorded
1690 // information is restored from the archive at runtime.
1691 subgraph_info->add_subgraph_entry_field(field_offset, f);
1692 log_info(cds, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1693 }
1694 } else {
1695 // The field contains null, we still need to record the entry point,
1696 // so it can be restored at runtime.
1697 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1698 }
1699 }
1700
1701 #ifndef PRODUCT
1702 class VerifySharedOopClosure: public BasicOopIterateClosure {
1703 public:
1704 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1705 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1706
1707 protected:
1708 template <class T> void do_oop_work(T *p) {
1709 oop obj = RawAccess<>::oop_load(p);
1710 if (!CompressedOops::is_null(obj)) {
1711 HeapShared::verify_reachable_objects_from(obj);
1712 }
1713 }
1714 };
1715
1716 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1717 assert(CDSConfig::is_dumping_heap(), "dump time only");
1718 assert(k->is_shared_boot_class(), "must be boot class");
1719
1720 oop m = k->java_mirror();
1721 oop f = m->obj_field(field_offset);
1722 if (!CompressedOops::is_null(f)) {
1723 verify_subgraph_from(f);
1724 }
1725 }
1726
1727 void HeapShared::verify_subgraph_from(oop orig_obj) {
1728 if (!has_been_archived(orig_obj)) {
1729 // It's OK for the root of a subgraph to be not archived. See comments in
1730 // archive_reachable_objects_from().
1731 return;
1732 }
1733
1734 // Verify that all objects reachable from orig_obj are archived.
1735 init_seen_objects_table();
1736 verify_reachable_objects_from(orig_obj);
1737 delete_seen_objects_table();
1738 }
1739
1740 void HeapShared::verify_reachable_objects_from(oop obj) {
1741 _num_total_verifications ++;
1742 if (java_lang_Class::is_instance(obj)) {
1743 obj = scratch_java_mirror(obj);
1744 assert(obj != nullptr, "must be");
1745 }
1746 if (!has_been_seen_during_subgraph_recording(obj)) {
1747 set_has_been_seen_during_subgraph_recording(obj);
1748 assert(has_been_archived(obj), "must be");
1749 VerifySharedOopClosure walker;
1750 obj->oop_iterate(&walker);
1751 }
1752 }
1753 #endif
1754
1755 void HeapShared::check_special_subgraph_classes() {
1756 if (CDSConfig::is_initing_classes_at_dump_time()) {
1757 // We can have aot-initialized classes (such as Enums) that can reference objects
1758 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
1759 // aot-initialize classes that are "safe".
1760 //
1761 // TODO: we need an automatic tool that checks the safety of aot-initialized
1762 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
1763 return;
1764 } else {
1765 // In this case, the special subgraph should contain a few specific types
1766 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
1767 int num = klasses->length();
1768 for (int i = 0; i < num; i++) {
1769 Klass* subgraph_k = klasses->at(i);
1770 Symbol* name = subgraph_k->name();
1771 if (subgraph_k->is_instance_klass() &&
1772 name != vmSymbols::java_lang_Class() &&
1773 name != vmSymbols::java_lang_String() &&
1774 name != vmSymbols::java_lang_ArithmeticException() &&
1775 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
1776 name != vmSymbols::java_lang_ArrayStoreException() &&
1777 name != vmSymbols::java_lang_ClassCastException() &&
1778 name != vmSymbols::java_lang_InternalError() &&
1779 name != vmSymbols::java_lang_NullPointerException()) {
1780 ResourceMark rm;
1781 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
1782 }
1783 }
1784 }
1785 }
1786
1787 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
1788 HeapShared::PendingOop HeapShared::_object_being_archived;
1789 int HeapShared::_num_new_walked_objs;
1790 int HeapShared::_num_new_archived_objs;
1791 int HeapShared::_num_old_recorded_klasses;
1792
1793 int HeapShared::_num_total_subgraph_recordings = 0;
1794 int HeapShared::_num_total_walked_objs = 0;
1795 int HeapShared::_num_total_archived_objs = 0;
1796 int HeapShared::_num_total_recorded_klasses = 0;
1797 int HeapShared::_num_total_verifications = 0;
1798
1799 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
1800 return _seen_objects_table->get(obj) != nullptr;
1801 }
1802
1803 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
1804 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
1805 _seen_objects_table->put_when_absent(obj, true);
1806 _seen_objects_table->maybe_grow();
1807 ++ _num_new_walked_objs;
1808 }
1809
1810 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
1811 log_info(cds, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
1812 init_subgraph_info(k, is_full_module_graph);
1813 init_seen_objects_table();
1814 _num_new_walked_objs = 0;
1815 _num_new_archived_objs = 0;
1816 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
1817 }
1818
1819 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
1820 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
1821 _num_old_recorded_klasses;
1822 log_info(cds, heap)("Done recording subgraph(s) for archived fields in %s: "
1823 "walked %d objs, archived %d new objs, recorded %d classes",
1824 class_name, _num_new_walked_objs, _num_new_archived_objs,
1825 num_new_recorded_klasses);
1826
1827 delete_seen_objects_table();
1828
1829 _num_total_subgraph_recordings ++;
1830 _num_total_walked_objs += _num_new_walked_objs;
1831 _num_total_archived_objs += _num_new_archived_objs;
1832 _num_total_recorded_klasses += num_new_recorded_klasses;
1833 }
1834
1835 class ArchivableStaticFieldFinder: public FieldClosure {
1836 InstanceKlass* _ik;
1837 Symbol* _field_name;
1838 bool _found;
1839 int _offset;
1840 public:
1841 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
1842 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
1843
1844 virtual void do_field(fieldDescriptor* fd) {
1845 if (fd->name() == _field_name) {
1846 assert(!_found, "fields can never be overloaded");
1847 if (is_reference_type(fd->field_type())) {
1848 _found = true;
1849 _offset = fd->offset();
1850 }
1851 }
1852 }
1853 bool found() { return _found; }
1854 int offset() { return _offset; }
1855 };
1856
1857 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
1858 TRAPS) {
1859 for (int i = 0; fields[i].valid(); i++) {
1860 ArchivableStaticFieldInfo* info = &fields[i];
1861 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1862 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
1863 ResourceMark rm; // for stringStream::as_string() etc.
1864
1865 #ifndef PRODUCT
1866 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
1867 const char* test_class_name = ArchiveHeapTestClass;
1868 #else
1869 bool is_test_class = false;
1870 const char* test_class_name = ""; // avoid C++ printf checks warnings.
1871 #endif
1872
1873 if (is_test_class) {
1874 log_warning(cds)("Loading ArchiveHeapTestClass %s ...", test_class_name);
1875 }
1876
1877 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
1878 if (HAS_PENDING_EXCEPTION) {
1879 CLEAR_PENDING_EXCEPTION;
1880 stringStream st;
1881 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
1882 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1883 }
1884
1885 if (!k->is_instance_klass()) {
1886 stringStream st;
1887 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
1888 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1889 }
1890
1891 InstanceKlass* ik = InstanceKlass::cast(k);
1892 assert(InstanceKlass::cast(ik)->is_shared_boot_class(),
1893 "Only support boot classes");
1894
1895 if (is_test_class) {
1896 if (ik->module()->is_named()) {
1897 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
1898 // core-lib classes. You need to at least append to the bootclasspath.
1899 stringStream st;
1900 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
1901 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1902 }
1903
1904 if (ik->package() != nullptr) {
1905 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
1906 stringStream st;
1907 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
1908 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1909 }
1910 } else {
1911 if (ik->module()->name() != vmSymbols::java_base()) {
1912 // We don't want to deal with cases when a module is unavailable at runtime.
1913 // FUTURE -- load from archived heap only when module graph has not changed
1914 // between dump and runtime.
1915 stringStream st;
1916 st.print("%s is not in java.base module", info->klass_name);
1917 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1918 }
1919 }
1920
1921 if (is_test_class) {
1922 log_warning(cds)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
1923 }
1924 ik->initialize(CHECK);
1925
1926 ArchivableStaticFieldFinder finder(ik, field_name);
1927 ik->do_local_static_fields(&finder);
1928 if (!finder.found()) {
1929 stringStream st;
1930 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
1931 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
1932 }
1933
1934 info->klass = ik;
1935 info->offset = finder.offset();
1936 }
1937 }
1938
1939 void HeapShared::init_subgraph_entry_fields(TRAPS) {
1940 assert(CDSConfig::is_dumping_heap(), "must be");
1941 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
1942 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
1943 if (CDSConfig::is_dumping_full_module_graph()) {
1944 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
1945 }
1946 }
1947
1948 #ifndef PRODUCT
1949 void HeapShared::setup_test_class(const char* test_class_name) {
1950 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
1951 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
1952 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
1953 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
1954
1955 if (test_class_name != nullptr) {
1956 p[num_slots - 2].klass_name = test_class_name;
1957 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
1958 }
1959 }
1960
1961 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
1962 // during runtime. This may be called before the module system is initialized so
1963 // we cannot rely on InstanceKlass::module(), etc.
1964 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
1965 if (_test_class != nullptr) {
1966 if (ik == _test_class) {
1967 return true;
1968 }
1969 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
1970 if (klasses == nullptr) {
1971 return false;
1972 }
1973
1974 for (int i = 0; i < klasses->length(); i++) {
1975 Klass* k = klasses->at(i);
1976 if (k == ik) {
1977 Symbol* name;
1978 if (k->is_instance_klass()) {
1979 name = InstanceKlass::cast(k)->name();
1980 } else if (k->is_objArray_klass()) {
1981 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
1982 if (!bk->is_instance_klass()) {
1983 return false;
1984 }
1985 name = bk->name();
1986 } else {
1987 return false;
1988 }
1989
1990 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
1991 // to be:
1992 // (A) java.base classes (which must not be in the unnamed module)
1993 // (B) test classes which must be in the unnamed package of the unnamed module.
1994 // So if we see a '/' character in the class name, it must be in (A);
1995 // otherwise it must be in (B).
1996 if (name->index_of_at(0, "/", 1) >= 0) {
1997 return false; // (A)
1998 }
1999
2000 return true; // (B)
2001 }
2002 }
2003 }
2004
2005 return false;
2006 }
2007
2008 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2009 Klass* k = _test_class;
2010 if (k != nullptr && ArchiveHeapLoader::is_in_use()) {
2011 JavaThread* THREAD = current;
2012 ExceptionMark em(THREAD);
2013 const ArchivedKlassSubGraphInfoRecord* record =
2014 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2015
2016 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2017 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2018 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2019 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2020 if (record != nullptr) {
2021 init_archived_fields_for(k, record);
2022 }
2023 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2024 }
2025 }
2026 #endif
2027
2028 void HeapShared::init_for_dumping(TRAPS) {
2029 if (CDSConfig::is_dumping_heap()) {
2030 setup_test_class(ArchiveHeapTestClass);
2031 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
2032 init_subgraph_entry_fields(CHECK);
2033 }
2034 }
2035
2036 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2037 bool is_full_module_graph) {
2038 _num_total_subgraph_recordings = 0;
2039 _num_total_walked_objs = 0;
2040 _num_total_archived_objs = 0;
2041 _num_total_recorded_klasses = 0;
2042 _num_total_verifications = 0;
2043
2044 // For each class X that has one or more archived fields:
2045 // [1] Dump the subgraph of each archived field
2046 // [2] Create a list of all the class of the objects that can be reached
2047 // by any of these static fields.
2048 // At runtime, these classes are initialized before X's archived fields
2049 // are restored by HeapShared::initialize_from_archived_subgraph().
2050 for (int i = 0; fields[i].valid(); ) {
2051 ArchivableStaticFieldInfo* info = &fields[i];
2052 const char* klass_name = info->klass_name;
2053 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2054
2055 // If you have specified consecutive fields of the same klass in
2056 // fields[], these will be archived in the same
2057 // {start_recording_subgraph ... done_recording_subgraph} pass to
2058 // save time.
2059 for (; fields[i].valid(); i++) {
2060 ArchivableStaticFieldInfo* f = &fields[i];
2061 if (f->klass_name != klass_name) {
2062 break;
2063 }
2064
2065 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2066 f->offset, f->field_name);
2067 }
2068 done_recording_subgraph(info->klass, klass_name);
2069 }
2070
2071 log_info(cds, heap)("Archived subgraph records = %d",
2072 _num_total_subgraph_recordings);
2073 log_info(cds, heap)(" Walked %d objects", _num_total_walked_objs);
2074 log_info(cds, heap)(" Archived %d objects", _num_total_archived_objs);
2075 log_info(cds, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
2076
2077 #ifndef PRODUCT
2078 for (int i = 0; fields[i].valid(); i++) {
2079 ArchivableStaticFieldInfo* f = &fields[i];
2080 verify_subgraph_from_static_field(f->klass, f->offset);
2081 }
2082 log_info(cds, heap)(" Verified %d references", _num_total_verifications);
2083 #endif
2084 }
2085
2086 // Not all the strings in the global StringTable are dumped into the archive, because
2087 // some of those strings may be only referenced by classes that are excluded from
2088 // the archive. We need to explicitly mark the strings that are:
2089 // [1] used by classes that WILL be archived;
2090 // [2] included in the SharedArchiveConfigFile.
2091 void HeapShared::add_to_dumped_interned_strings(oop string) {
2092 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
2093 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(string), "must be");
2094 bool created;
2095 _dumped_interned_strings->put_if_absent(string, true, &created);
2096 if (created) {
2097 // Prevent string deduplication from changing the value field to
2098 // something not in the archive.
2099 java_lang_String::set_deduplication_forbidden(string);
2100 _dumped_interned_strings->maybe_grow();
2101 }
2102 }
2103
2104 bool HeapShared::is_dumped_interned_string(oop o) {
2105 return _dumped_interned_strings->get(o) != nullptr;
2106 }
2107
2108 void HeapShared::debug_trace() {
2109 ResourceMark rm;
2110 oop referrer = _object_being_archived.referrer();
2111 if (referrer != nullptr) {
2112 LogStream ls(Log(cds, heap)::error());
2113 ls.print_cr("Reference trace");
2114 CDSHeapVerifier::trace_to_root(&ls, referrer);
2115 }
2116 }
2117
2118 #ifndef PRODUCT
2119 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2120 // region. This way we can quickly relocate all the pointers without using
2121 // BasicOopIterateClosure at runtime.
2122 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2123 void* _start;
2124 BitMap *_oopmap;
2125 int _num_total_oops;
2126 int _num_null_oops;
2127 public:
2128 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2129 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2130
2131 virtual void do_oop(narrowOop* p) {
2132 assert(UseCompressedOops, "sanity");
2133 _num_total_oops ++;
2134 narrowOop v = *p;
2135 if (!CompressedOops::is_null(v)) {
2136 size_t idx = p - (narrowOop*)_start;
2137 _oopmap->set_bit(idx);
2138 } else {
2139 _num_null_oops ++;
2140 }
2141 }
2142 virtual void do_oop(oop* p) {
2143 assert(!UseCompressedOops, "sanity");
2144 _num_total_oops ++;
2145 if ((*p) != nullptr) {
2146 size_t idx = p - (oop*)_start;
2147 _oopmap->set_bit(idx);
2148 } else {
2149 _num_null_oops ++;
2150 }
2151 }
2152 int num_total_oops() const { return _num_total_oops; }
2153 int num_null_oops() const { return _num_null_oops; }
2154 };
2155 #endif
2156
2157 void HeapShared::count_allocation(size_t size) {
2158 _total_obj_count ++;
2159 _total_obj_size += size;
2160 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2161 if (size <= (size_t(1) << i)) {
2162 _alloc_count[i] ++;
2163 _alloc_size[i] += size;
2164 return;
2165 }
2166 }
2167 }
2168
2169 static double avg_size(size_t size, size_t count) {
2170 double avg = 0;
2171 if (count > 0) {
2172 avg = double(size * HeapWordSize) / double(count);
2173 }
2174 return avg;
2175 }
2176
2177 void HeapShared::print_stats() {
2178 size_t huge_count = _total_obj_count;
2179 size_t huge_size = _total_obj_size;
2180
2181 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2182 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2183 size_t count = _alloc_count[i];
2184 size_t size = _alloc_size[i];
2185 log_info(cds, heap)("%8zu objects are <= %-6zu"
2186 " bytes (total %8zu bytes, avg %8.1f bytes)",
2187 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2188 huge_count -= count;
2189 huge_size -= size;
2190 }
2191
2192 log_info(cds, heap)("%8zu huge objects (total %8zu bytes"
2193 ", avg %8.1f bytes)",
2194 huge_count, huge_size * HeapWordSize,
2195 avg_size(huge_size, huge_count));
2196 log_info(cds, heap)("%8zu total objects (total %8zu bytes"
2197 ", avg %8.1f bytes)",
2198 _total_obj_count, _total_obj_size * HeapWordSize,
2199 avg_size(_total_obj_size, _total_obj_count));
2200 }
2201
2202 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2203 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2204 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2205 if (k == nullptr) {
2206 return false;
2207 } else {
2208 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2209 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2210 fieldDescriptor fd;
2211 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2212 oop m = k->java_mirror();
2213 oop f = m->obj_field(fd.offset());
2214 if (CompressedOops::is_null(f)) {
2215 return false;
2216 }
2217 } else {
2218 return false;
2219 }
2220 }
2221 return true;
2222 }
2223
2224 #endif // INCLUDE_CDS_JAVA_HEAP