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