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