1 /*
2 * Copyright (c) 2018, 2026, 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/aotCompressedPointers.hpp"
29 #include "cds/aotLogging.hpp"
30 #include "cds/aotMappedHeapLoader.hpp"
31 #include "cds/aotMappedHeapWriter.hpp"
32 #include "cds/aotMetaspace.hpp"
33 #include "cds/aotOopChecker.hpp"
34 #include "cds/aotReferenceObjSupport.hpp"
35 #include "cds/aotStreamedHeapLoader.hpp"
36 #include "cds/aotStreamedHeapWriter.hpp"
37 #include "cds/archiveBuilder.hpp"
38 #include "cds/archiveUtils.hpp"
39 #include "cds/cds_globals.hpp"
40 #include "cds/cdsConfig.hpp"
41 #include "cds/cdsEnumKlass.hpp"
42 #include "cds/cdsHeapVerifier.hpp"
43 #include "cds/heapShared.inline.hpp"
44 #include "cds/regeneratedClasses.hpp"
45 #include "classfile/classLoaderData.hpp"
46 #include "classfile/javaClasses.inline.hpp"
47 #include "classfile/modules.hpp"
48 #include "classfile/stringTable.hpp"
49 #include "classfile/symbolTable.hpp"
50 #include "classfile/systemDictionary.hpp"
51 #include "classfile/systemDictionaryShared.hpp"
52 #include "classfile/vmClasses.hpp"
53 #include "classfile/vmSymbols.hpp"
54 #include "gc/shared/collectedHeap.hpp"
55 #include "gc/shared/gcLocker.hpp"
56 #include "gc/shared/gcVMOperations.hpp"
57 #include "logging/log.hpp"
58 #include "logging/logStream.hpp"
59 #include "memory/iterator.inline.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/compressedOops.inline.hpp"
63 #include "oops/fieldStreams.inline.hpp"
64 #include "oops/objArrayOop.inline.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "oops/oopHandle.inline.hpp"
67 #include "oops/typeArrayOop.inline.hpp"
68 #include "prims/jvmtiExport.hpp"
69 #include "runtime/arguments.hpp"
70 #include "runtime/fieldDescriptor.inline.hpp"
71 #include "runtime/globals_extension.hpp"
72 #include "runtime/init.hpp"
73 #include "runtime/javaCalls.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/safepointVerifiers.hpp"
76 #include "utilities/bitMap.inline.hpp"
77 #include "utilities/copy.hpp"
78 #if INCLUDE_G1GC
79 #include "gc/g1/g1CollectedHeap.hpp"
80 #endif
81
82 #if INCLUDE_CDS_JAVA_HEAP
83
84 struct ArchivableStaticFieldInfo {
85 const char* klass_name;
86 const char* field_name;
87 InstanceKlass* klass;
88 int offset;
89 BasicType type;
90
91 ArchivableStaticFieldInfo(const char* k, const char* f)
92 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
93
94 bool valid() {
95 return klass_name != nullptr;
96 }
97 };
98
99 HeapArchiveMode HeapShared::_heap_load_mode = HeapArchiveMode::_uninitialized;
100 HeapArchiveMode HeapShared::_heap_write_mode = HeapArchiveMode::_uninitialized;
101
102 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
103 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
104 size_t HeapShared::_total_obj_count;
105 size_t HeapShared::_total_obj_size;
106
107 #ifndef PRODUCT
108 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
109 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
110 static const char* _test_class_name = nullptr;
111 static Klass* _test_class = nullptr;
112 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
113 #endif
114
115 #ifdef ASSERT
116 // All classes that have at least one instance in the cached heap.
117 static ArchivableKlassTable* _dumptime_classes_with_cached_oops = nullptr;
118 static Array<Klass*>* _runtime_classes_with_cached_oops = nullptr;
119 #endif
120
121 //
122 // If you add new entries to the following tables, you should know what you're doing!
123 //
124
125 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
126 {"java/lang/Integer$IntegerCache", "archivedCache"},
127 {"java/lang/Long$LongCache", "archivedCache"},
128 {"java/lang/Byte$ByteCache", "archivedCache"},
129 {"java/lang/Short$ShortCache", "archivedCache"},
130 {"java/lang/Character$CharacterCache", "archivedCache"},
131 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
132 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
133 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
134 {"java/util/ImmutableCollections", "archivedObjects"},
135 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
136 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
137 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
138
139 // full module graph support
140 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
141 {ARCHIVED_BOOT_LAYER_CLASS, ARCHIVED_BOOT_LAYER_FIELD},
142 {"java/lang/Module$ArchivedData", "archivedData"},
143
144 #ifndef PRODUCT
145 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
146 #endif
147 {nullptr, nullptr},
148 };
149
150 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
151 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
152 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;
153 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
154 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
155
156 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
157 for (int i = 0; fields[i].valid(); i++) {
158 if (fields[i].klass == ik) {
159 return true;
160 }
161 }
162 return false;
163 }
164
165 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
166 assert(CDSConfig::is_dumping_heap(), "dump-time only");
167 if (CDSConfig::is_dumping_klass_subgraphs()) {
168 // Legacy CDS archive support (to be deprecated)
169 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik);
170 } else {
171 return false;
172 }
173 }
174
175 oop HeapShared::CachedOopInfo::orig_referrer() const {
176 return _orig_referrer.resolve();
177 }
178
179 // This is a simple hashing of the oop's address. This function is used
180 // while copying the oops into the AOT heap region. We don't want to
181 // have any side effects during the copying, so we avoid calling
182 // p->identity_hash() which can update the object header.
183 unsigned HeapShared::oop_address_hash(oop const& p) {
184 assert(SafepointSynchronize::is_at_safepoint() ||
185 JavaThread::current()->is_in_no_safepoint_scope(), "sanity");
186 return primitive_hash(cast_from_oop<intptr_t>(p));
187 }
188
189 // About the hashcode in the cached objects:
190 // - If a source object has a hashcode, it must be copied into the cache.
191 // That's because some cached hashtables are laid out using this hashcode.
192 // - If a source object doesn't have a hashcode, we avoid computing it while
193 // copying the objects into the cache. This will allow the hashcode to be
194 // dynamically and randomly computed in each production, which generally
195 // desirable to make the hashcodes more random between runs.
196 unsigned HeapShared::archived_object_cache_hash(OopHandle const& oh) {
197 oop o = oh.resolve();
198 if (o == nullptr) {
199 return 0;
200 }
201 if (!_use_identity_hash_for_archived_object_cache) {
202 // This is called while we are copying the objects. Don't call o->identity_hash()
203 // as that will update the object header.
204 return oop_address_hash(o);
205 } else {
206 // This is called after all objects are copied. It's OK to update
207 // the object's hashcode.
208 //
209 // This may be called after we have left the AOT dumping safepoint.
210 // Objects in archived_object_cache() may be moved by the GC, so we
211 // can't use the address of o for computing the hash.
212 return o->identity_hash();
213 }
214 }
215
216 bool HeapShared::oop_handle_equals(const OopHandle& a, const OopHandle& b) {
217 return a.resolve() == b.resolve();
218 }
219
220 static void reset_states(oop obj, TRAPS) {
221 Handle h_obj(THREAD, obj);
222 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
223 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
224 Symbol* method_sig = vmSymbols::void_method_signature();
225
226 while (klass != nullptr) {
227 Method* method = klass->find_method(method_name, method_sig);
228 if (method != nullptr) {
229 assert(method->is_private(), "must be");
230 if (log_is_enabled(Debug, aot)) {
231 ResourceMark rm(THREAD);
232 log_debug(aot)(" calling %s", method->name_and_sig_as_C_string());
233 }
234 JavaValue result(T_VOID);
235 JavaCalls::call_special(&result, h_obj, klass,
236 method_name, method_sig, CHECK);
237 }
238 klass = klass->super();
239 }
240 }
241
242 void HeapShared::reset_archived_object_states(TRAPS) {
243 assert(CDSConfig::is_dumping_heap(), "dump-time only");
244 log_debug(aot)("Resetting platform loader");
245 reset_states(SystemDictionary::java_platform_loader(), CHECK);
246 log_debug(aot)("Resetting system loader");
247 reset_states(SystemDictionary::java_system_loader(), CHECK);
248
249 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
250 // directly used for class loading, but rather is used by the core library
251 // to keep track of resources, etc, loaded by the null class loader.
252 //
253 // Note, this object is non-null, and is not the same as
254 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
255 // which is null.
256 log_debug(aot)("Resetting boot loader");
257 JavaValue result(T_OBJECT);
258 JavaCalls::call_static(&result,
259 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
260 vmSymbols::bootLoader_name(),
261 vmSymbols::void_BuiltinClassLoader_signature(),
262 CHECK);
263 Handle boot_loader(THREAD, result.get_oop());
264 reset_states(boot_loader(), CHECK);
265 }
266
267 void HeapShared::ensure_determinism(TRAPS) {
268 TempNewSymbol class_name = SymbolTable::new_symbol("jdk/internal/util/WeakReferenceKey");
269 TempNewSymbol method_name = SymbolTable::new_symbol("ensureDeterministicAOTCache");
270
271 Klass* weak_ref_key_class = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
272 precond(weak_ref_key_class != nullptr);
273
274 log_debug(aot)("Calling WeakReferenceKey::ensureDeterministicAOTCache(Object.class)");
275 JavaValue result(T_BOOLEAN);
276 JavaCalls::call_static(&result,
277 weak_ref_key_class,
278 method_name,
279 vmSymbols::void_boolean_signature(),
280 CHECK);
281 assert(result.get_jboolean() == false, "sanity");
282 }
283
284 void HeapShared::prepare_for_archiving(TRAPS) {
285 reset_archived_object_states(CHECK);
286 ensure_determinism(CHECK);
287 }
288
289 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
290
291 // Controls the hashing method for the _archived_object_cache.
292 // Changes from false to true once, after all objects are copied,
293 // inside make_archived_object_cache_gc_safe().
294 // See archived_object_cache_hash() for more details.
295 bool HeapShared::_use_identity_hash_for_archived_object_cache = false;
296
297 bool HeapShared::is_archived_heap_in_use() {
298 if (HeapShared::is_loading()) {
299 if (HeapShared::is_loading_streaming_mode()) {
300 return AOTStreamedHeapLoader::is_in_use();
301 } else {
302 return AOTMappedHeapLoader::is_in_use();
303 }
304 }
305
306 return false;
307 }
308
309 bool HeapShared::can_use_archived_heap() {
310 FileMapInfo* static_mapinfo = FileMapInfo::current_info();
311 if (static_mapinfo == nullptr) {
312 return false;
313 }
314 if (!static_mapinfo->has_heap_region()) {
315 return false;
316 }
317 if (!static_mapinfo->object_streaming_mode() &&
318 !Universe::heap()->can_load_archived_objects() &&
319 !UseG1GC) {
320 // Incompatible object format
321 return false;
322 }
323
324 return true;
325 }
326
327 bool HeapShared::is_too_large_to_archive(size_t size) {
328 if (HeapShared::is_writing_streaming_mode()) {
329 return false;
330 } else {
331 return AOTMappedHeapWriter::is_too_large_to_archive(size);
332 }
333 }
334
335 bool HeapShared::is_too_large_to_archive(oop obj) {
336 if (HeapShared::is_writing_streaming_mode()) {
337 return false;
338 } else {
339 return AOTMappedHeapWriter::is_too_large_to_archive(obj);
340 }
341 }
342
343 bool HeapShared::is_string_too_large_to_archive(oop string) {
344 typeArrayOop value = java_lang_String::value_no_keepalive(string);
345 return is_too_large_to_archive(value);
346 }
347
348 void HeapShared::initialize_loading_mode(HeapArchiveMode mode) {
349 assert(_heap_load_mode == HeapArchiveMode::_uninitialized, "already set?");
350 assert(mode != HeapArchiveMode::_uninitialized, "sanity");
351 _heap_load_mode = mode;
352 };
353
354 void HeapShared::initialize_writing_mode() {
355 assert(!FLAG_IS_ERGO(AOTStreamableObjects), "Should not have been ergonomically set yet");
356
357 if (!CDSConfig::is_dumping_archive()) {
358 // We use FLAG_IS_CMDLINE below because we are specifically looking to warn
359 // a user that explicitly sets the flag on the command line for a JVM that is
360 // not dumping an archive.
361 if (FLAG_IS_CMDLINE(AOTStreamableObjects)) {
362 log_warning(cds)("-XX:%cAOTStreamableObjects was specified, "
363 "AOTStreamableObjects is only used for writing "
364 "the AOT cache.",
365 AOTStreamableObjects ? '+' : '-');
366 }
367 }
368
369 // The below checks use !FLAG_IS_DEFAULT instead of FLAG_IS_CMDLINE
370 // because the one step AOT cache creation transfers the AOTStreamableObjects
371 // flag value from the training JVM to the assembly JVM using an environment
372 // variable that sets the flag as ERGO in the assembly JVM.
373 if (FLAG_IS_DEFAULT(AOTStreamableObjects)) {
374 // By default, the value of AOTStreamableObjects should match !UseCompressedOops.
375 FLAG_SET_DEFAULT(AOTStreamableObjects, !UseCompressedOops);
376 } else if (!AOTStreamableObjects && UseZGC) {
377 // Never write mapped heap with ZGC
378 if (CDSConfig::is_dumping_archive()) {
379 log_warning(cds)("Heap archiving without streaming not supported for -XX:+UseZGC");
380 }
381 FLAG_SET_ERGO(AOTStreamableObjects, true);
382 }
383
384 if (CDSConfig::is_dumping_archive()) {
385 // Select default mode
386 assert(_heap_write_mode == HeapArchiveMode::_uninitialized, "already initialized?");
387 _heap_write_mode = AOTStreamableObjects ? HeapArchiveMode::_streaming : HeapArchiveMode::_mapping;
388 }
389 }
390
391 void HeapShared::initialize_streaming() {
392 assert(is_loading_streaming_mode(), "shouldn't call this");
393 if (can_use_archived_heap()) {
394 AOTStreamedHeapLoader::initialize();
395 }
396 }
397
398 void HeapShared::enable_gc() {
399 #ifdef ASSERT
400 // At this point, a GC may start and will be able to see some or all
401 // of the cached oops. The class of each oop seen by the GC must have
402 // already been loaded. One function with such a requirement is
403 // ClaimMetadataVisitingOopIterateClosure::do_klass().
404 if (is_archived_heap_in_use()) {
405 Array<Klass*>* klasses = _runtime_classes_with_cached_oops;
406
407 for (int i = 0; i < klasses->length(); i++) {
408 assert(klasses->at(i)->class_loader_data() != nullptr,
409 "class of cached oop must have been loaded");
410 }
411 }
412 #endif
413
414 if (AOTStreamedHeapLoader::is_in_use()) {
415 AOTStreamedHeapLoader::enable_gc();
416 }
417 }
418
419 void HeapShared::materialize_thread_object() {
420 if (AOTStreamedHeapLoader::is_in_use()) {
421 AOTStreamedHeapLoader::materialize_thread_object();
422 }
423 }
424
425 void HeapShared::archive_interned_string(oop string) {
426 assert(HeapShared::is_writing_mapping_mode(), "Only used by this mode");
427 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, string);
428 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
429 }
430
431 void HeapShared::finalize_initialization(FileMapInfo* static_mapinfo) {
432 if (HeapShared::is_loading()) {
433 if (HeapShared::is_loading_streaming_mode()) {
434 // Heap initialization can be done only after vtables are initialized by ReadClosure.
435 AOTStreamedHeapLoader::finish_initialization(static_mapinfo);
436 } else {
437 // Finish up archived heap initialization. These must be
438 // done after ReadClosure.
439 AOTMappedHeapLoader::finish_initialization(static_mapinfo);
440 }
441 }
442 }
443
444 void HeapShared::make_archived_object_cache_gc_safe() {
445 ArchivedObjectCache* new_cache = new (mtClass)ArchivedObjectCache(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
446
447 // It's safe to change the behavior of the hash function now, because iterate_all()
448 // doesn't call the hash function.
449 // See archived_object_cache_hash() for more details.
450 assert(_use_identity_hash_for_archived_object_cache == false, "happens only once");
451 _use_identity_hash_for_archived_object_cache = true;
452
453 // Copy all CachedOopInfo into a new table using a different hashing algorithm
454 archived_object_cache()->iterate_all([&] (OopHandle oh, CachedOopInfo info) {
455 new_cache->put_when_absent(oh, info);
456 });
457
458 destroy_archived_object_cache();
459 _archived_object_cache = new_cache;
460 }
461
462 HeapShared::CachedOopInfo* HeapShared::get_cached_oop_info(oop obj) {
463 OopHandle oh(Universe::vm_global(), obj);
464 CachedOopInfo* result = _archived_object_cache->get(oh);
465 oh.release(Universe::vm_global());
466 return result;
467 }
468
469 bool HeapShared::has_been_archived(oop obj) {
470 assert(CDSConfig::is_dumping_heap(), "dump-time only");
471 return get_cached_oop_info(obj) != nullptr;
472 }
473
474 int HeapShared::append_root(oop obj) {
475 assert(SafepointSynchronize::is_at_safepoint(), "sanity");
476 assert(CDSConfig::is_dumping_heap(), "dump-time only");
477 assert(_pending_roots != nullptr, "sanity");
478
479 if (obj == nullptr) {
480 assert(_pending_roots->at(0) == nullptr, "root index 0 always maps to null");
481 return 0;
482 } else if (CDSConfig::is_dumping_aot_linked_classes()) {
483 // The AOT compiler may refer the same obj many times, so we
484 // should use the same index for this oop to avoid excessive entries
485 // in the roots array.
486 CachedOopInfo* obj_info = get_cached_oop_info(obj);
487 assert(obj_info != nullptr, "must be archived");
488
489 if (obj_info->root_index() > 0) {
490 return obj_info->root_index();
491 } else {
492 assert(obj_info->root_index() < 0, "must not be zero");
493 int i = _pending_roots->append(obj);
494 obj_info->set_root_index(i);
495 return i;
496 }
497 } else {
498 return _pending_roots->append(obj);
499 }
500 }
501
502 int HeapShared::get_root_index(oop obj) {
503 if (java_lang_Class::is_instance(obj)) {
504 obj = scratch_java_mirror(obj);
505 }
506
507 CachedOopInfo* obj_info = get_cached_oop_info(obj);
508 const char* error = nullptr;
509 if (obj_info == nullptr) {
510 error = "Not a cached oop";
511 } else if (obj_info->root_index() < 0) {
512 error = "Not a cached oop root";
513 } else {
514 return obj_info->root_index();
515 }
516
517 ResourceMark rm;
518 log_debug(aot, codecache, oops)("%s: " INTPTR_FORMAT " (%s)", error,
519 cast_from_oop<uintptr_t>(obj),
520 obj->klass()->external_name());
521 return -1;
522 }
523
524 oop HeapShared::get_root(int index, bool clear) {
525 assert(index >= 0, "sanity");
526 assert(is_archived_heap_in_use(), "getting roots into heap that is not used");
527
528 oop result;
529 if (HeapShared::is_loading_streaming_mode()) {
530 result = AOTStreamedHeapLoader::get_root(index);
531 } else {
532 assert(HeapShared::is_loading_mapping_mode(), "must be");
533 result = AOTMappedHeapLoader::get_root(index);
534 }
535
536 if (clear) {
537 clear_root(index);
538 }
539
540 return result;
541 }
542
543 void HeapShared::finish_materialize_objects() {
544 if (AOTStreamedHeapLoader::is_in_use()) {
545 AOTStreamedHeapLoader::finish_materialize_objects();
546 }
547 }
548
549 void HeapShared::clear_root(int index) {
550 if (CDSConfig::is_using_aot_linked_classes()) {
551 // When AOT linked classes are in use, all roots will be in use all
552 // the time, there's no benefit for clearing the roots. Also, we
553 // can't clear the roots as they can be shared.
554 return;
555 }
556
557 assert(index >= 0, "sanity");
558 assert(CDSConfig::is_using_archive(), "must be");
559 if (is_archived_heap_in_use()) {
560 if (log_is_enabled(Debug, aot, heap)) {
561 log_debug(aot, heap)("Clearing root %d: was %zu", index, p2i(get_root(index, false /* clear */)));
562 }
563 if (HeapShared::is_loading_streaming_mode()) {
564 AOTStreamedHeapLoader::clear_root(index);
565 } else {
566 assert(HeapShared::is_loading_mapping_mode(), "must be");
567 AOTMappedHeapLoader::clear_root(index);
568 }
569 }
570 }
571
572 bool HeapShared::archive_object(oop obj, oop referrer, KlassSubGraphInfo* subgraph_info) {
573 assert(CDSConfig::is_dumping_heap(), "dump-time only");
574
575 assert(!obj->is_stackChunk(), "do not archive stack chunks");
576 if (has_been_archived(obj)) {
577 return true;
578 }
579
580 if (is_too_large_to_archive(obj)) {
581 log_debug(aot, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: %zu",
582 p2i(obj), obj->size());
583 debug_trace();
584 return false;
585 }
586
587 AOTArtifactFinder::add_cached_class(obj->klass());
588 AOTOopChecker::check(obj); // Make sure contents of this oop are safe.
589 count_allocation(obj->size());
590 DEBUG_ONLY(_dumptime_classes_with_cached_oops->add(obj->klass()));
591
592 if (HeapShared::is_writing_streaming_mode()) {
593 AOTStreamedHeapWriter::add_source_obj(obj);
594 } else {
595 AOTMappedHeapWriter::add_source_obj(obj);
596 }
597
598 OopHandle oh(Universe::vm_global(), obj);
599 CachedOopInfo info = make_cached_oop_info(obj, referrer);
600 archived_object_cache()->put_when_absent(oh, info);
601 archived_object_cache()->maybe_grow();
602
603 Klass* k = obj->klass();
604 if (k->is_instance_klass()) {
605 // Whenever we see a non-array Java object of type X, we mark X to be aot-initialized.
606 // This ensures that during the production run, whenever Java code sees a cached object
607 // of type X, we know that X is already initialized. (see TODO comment below ...)
608
609 if (InstanceKlass::cast(k)->is_enum_subclass()
610 // We can't rerun <clinit> of enum classes (see cdsEnumKlass.cpp) so
611 // we must store them as AOT-initialized.
612 || (subgraph_info == _dump_time_special_subgraph))
613 // TODO: we do this only for the special subgraph for now. Extending this to
614 // other subgraphs would require more refactoring of the core library (such as
615 // move some initialization logic into runtimeSetup()).
616 //
617 // For the other subgraphs, we have a weaker mechanism to ensure that
618 // all classes in a subgraph are initialized before the subgraph is programmatically
619 // returned from jdk.internal.misc.CDS::initializeFromArchive().
620 // See HeapShared::initialize_from_archived_subgraph().
621 {
622 AOTArtifactFinder::add_aot_inited_class(InstanceKlass::cast(k));
623 }
624
625 if (java_lang_Class::is_instance(obj)) {
626 Klass* mirror_k = java_lang_Class::as_Klass(obj);
627 if (mirror_k != nullptr) {
628 AOTArtifactFinder::add_cached_class(mirror_k);
629 }
630 } else if (java_lang_invoke_ResolvedMethodName::is_instance(obj)) {
631 Method* m = java_lang_invoke_ResolvedMethodName::vmtarget(obj);
632 if (m != nullptr) {
633 m = RegeneratedClasses::maybe_get_regenerated_object(m);
634 InstanceKlass* method_holder = m->method_holder();
635 AOTArtifactFinder::add_cached_class(method_holder);
636 }
637 }
638 }
639
640 if (log_is_enabled(Debug, aot, heap)) {
641 ResourceMark rm;
642 LogTarget(Debug, aot, heap) log;
643 LogStream out(log);
644 out.print("Archived heap object " PTR_FORMAT " : %s ",
645 p2i(obj), obj->klass()->external_name());
646 if (java_lang_Class::is_instance(obj)) {
647 Klass* k = java_lang_Class::as_Klass(obj);
648 if (k != nullptr) {
649 out.print("%s", k->external_name());
650 } else {
651 out.print("primitive");
652 }
653 }
654 out.cr();
655 }
656
657 return true;
658 }
659
660 class MetaspaceObjToOopHandleTable: public HashTable<MetaspaceObj*, OopHandle,
661 36137, // prime number
662 AnyObj::C_HEAP,
663 mtClassShared> {
664 public:
665 oop get_oop(MetaspaceObj* ptr) {
666 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
667 OopHandle* handle = get(ptr);
668 if (handle != nullptr) {
669 return handle->resolve();
670 } else {
671 return nullptr;
672 }
673 }
674 void set_oop(MetaspaceObj* ptr, oop o) {
675 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
676 OopHandle handle(Universe::vm_global(), o);
677 put_when_absent(ptr, handle);
678 }
679 void remove_oop(MetaspaceObj* ptr) {
680 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
681 OopHandle* handle = get(ptr);
682 if (handle != nullptr) {
683 handle->release(Universe::vm_global());
684 remove(ptr);
685 }
686 }
687 };
688
689 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
690 if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
691 _scratch_objects_table->set_oop(src, dest);
692 }
693 }
694
695 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
696 return (objArrayOop)_scratch_objects_table->get_oop(src);
697 }
698
699 void HeapShared::remove_scratch_resolved_references(ConstantPool* src) {
700 if (CDSConfig::is_dumping_heap()) {
701 _scratch_objects_table->remove_oop(src);
702 }
703 }
704
705 void HeapShared::init_dumping() {
706 _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
707 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
708 _pending_roots->append(nullptr); // root index 0 represents a null oop
709 DEBUG_ONLY(_dumptime_classes_with_cached_oops = new (mtClassShared)ArchivableKlassTable());
710 }
711
712 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
713 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
714 BasicType bt = (BasicType)i;
715 if (!is_reference_type(bt)) {
716 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, true, CHECK);
717 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
718 }
719 }
720 }
721
722 // Given java_mirror that represents a (primitive or reference) type T,
723 // return the "scratch" version that represents the same type T. Note
724 // that java_mirror will be returned if the mirror is already a scratch mirror.
725 //
726 // See java_lang_Class::create_scratch_mirror() for more info.
727 oop HeapShared::scratch_java_mirror(oop java_mirror) {
728 assert(java_lang_Class::is_instance(java_mirror), "must be");
729
730 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
731 BasicType bt = (BasicType)i;
732 if (!is_reference_type(bt)) {
733 if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
734 return java_mirror;
735 }
736 }
737 }
738
739 if (java_lang_Class::is_primitive(java_mirror)) {
740 return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
741 } else {
742 return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
743 }
744 }
745
746 oop HeapShared::scratch_java_mirror(BasicType t) {
747 assert((uint)t < T_VOID+1, "range check");
748 assert(!is_reference_type(t), "sanity");
749 return _scratch_basic_type_mirrors[t].resolve();
750 }
751
752 oop HeapShared::scratch_java_mirror(Klass* k) {
753 return _scratch_objects_table->get_oop(k);
754 }
755
756 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
757 _scratch_objects_table->set_oop(k, mirror);
758 }
759
760 void HeapShared::remove_scratch_objects(Klass* k) {
761 // Klass is being deallocated. Java mirror can still be alive, and it should not
762 // point to dead klass. We need to break the link from mirror to the Klass.
763 // See how InstanceKlass::deallocate_contents does it for normal mirrors.
764 oop mirror = _scratch_objects_table->get_oop(k);
765 if (mirror != nullptr) {
766 java_lang_Class::set_klass(mirror, nullptr);
767 }
768 _scratch_objects_table->remove_oop(k);
769 if (k->is_instance_klass()) {
770 _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
771 }
772 }
773
774 //TODO: we eventually want a more direct test for these kinds of things.
775 //For example the JVM could record some bit of context from the creation
776 //of the klass, such as who called the hidden class factory. Using
777 //string compares on names is fragile and will break as soon as somebody
778 //changes the names in the JDK code. See discussion in JDK-8342481 for
779 //related ideas about marking AOT-related classes.
780 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
781 return ik->is_hidden() &&
782 (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
783 ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
784 ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
785 ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
786 }
787
788 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
789 return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
790 }
791
792 bool HeapShared::is_string_concat_klass(InstanceKlass* ik) {
793 return ik->is_hidden() && ik->name()->starts_with("java/lang/String$$StringConcat");
794 }
795
796 bool HeapShared::is_archivable_hidden_klass(InstanceKlass* ik) {
797 return CDSConfig::is_dumping_method_handles() &&
798 (is_lambda_form_klass(ik) || is_lambda_proxy_klass(ik) || is_string_concat_klass(ik));
799 }
800
801
802 void HeapShared::copy_and_rescan_aot_inited_mirror(InstanceKlass* ik) {
803 ik->set_has_aot_initialized_mirror();
804
805 oop orig_mirror;
806 if (RegeneratedClasses::is_regenerated_object(ik)) {
807 InstanceKlass* orig_ik = RegeneratedClasses::get_original_object(ik);
808 precond(orig_ik->is_initialized());
809 orig_mirror = orig_ik->java_mirror();
810 } else {
811 precond(ik->is_initialized());
812 orig_mirror = ik->java_mirror();
813 }
814
815 oop m = scratch_java_mirror(ik);
816 int nfields = 0;
817 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
818 if (fs.access_flags().is_static()) {
819 fieldDescriptor& fd = fs.field_descriptor();
820 int offset = fd.offset();
821 switch (fd.field_type()) {
822 case T_OBJECT:
823 case T_ARRAY:
824 {
825 oop field_obj = orig_mirror->obj_field(offset);
826 if (offset == java_lang_Class::reflection_data_offset()) {
827 // Class::reflectData use SoftReference, which cannot be archived. Set it
828 // to null and it will be recreated at runtime.
829 field_obj = nullptr;
830 }
831 m->obj_field_put(offset, field_obj);
832 if (field_obj != nullptr) {
833 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
834 assert(success, "sanity");
835 }
836 }
837 break;
838 case T_BOOLEAN:
839 m->bool_field_put(offset, orig_mirror->bool_field(offset));
840 break;
841 case T_BYTE:
842 m->byte_field_put(offset, orig_mirror->byte_field(offset));
843 break;
844 case T_SHORT:
845 m->short_field_put(offset, orig_mirror->short_field(offset));
846 break;
847 case T_CHAR:
848 m->char_field_put(offset, orig_mirror->char_field(offset));
849 break;
850 case T_INT:
851 m->int_field_put(offset, orig_mirror->int_field(offset));
852 break;
853 case T_LONG:
854 m->long_field_put(offset, orig_mirror->long_field(offset));
855 break;
856 case T_FLOAT:
857 m->float_field_put(offset, orig_mirror->float_field(offset));
858 break;
859 case T_DOUBLE:
860 m->double_field_put(offset, orig_mirror->double_field(offset));
861 break;
862 default:
863 ShouldNotReachHere();
864 }
865 nfields ++;
866 }
867 }
868
869 oop class_data = java_lang_Class::class_data(orig_mirror);
870 java_lang_Class::set_class_data(m, class_data);
871 if (class_data != nullptr) {
872 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
873 assert(success, "sanity");
874 }
875
876 if (log_is_enabled(Debug, aot, init)) {
877 ResourceMark rm;
878 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
879 ik->is_hidden() ? " (hidden)" : "",
880 ik->is_enum_subclass() ? " (enum)" : "");
881 }
882 }
883
884 void HeapShared::copy_java_mirror(oop orig_mirror, oop scratch_m) {
885 // We need to retain the identity_hash, because it may have been used by some hashtables
886 // in the shared heap.
887 assert(!UseCompactObjectHeaders || scratch_m->mark().is_not_hashed_expanded(), "scratch mirror must have not-hashed-expanded state");
888 assert(!UseCompactObjectHeaders || !orig_mirror->mark().is_not_hashed_expanded(), "must not be not-hashed-expanded");
889 if (!orig_mirror->fast_no_hash_check()) {
890 intptr_t orig_mark = orig_mirror->mark().value();
891 intptr_t src_hash = orig_mirror->identity_hash();
892 if (UseCompactObjectHeaders) {
893 // We leave the cases not_hashed/not_hashed_expanded as they are.
894 assert(orig_mirror->mark().is_hashed_not_expanded() || orig_mirror->mark().is_hashed_expanded(), "must be hashed");
895 Klass* orig_klass = orig_mirror->klass();
896 narrowKlass nk = CompressedKlassPointers::encode(orig_klass);
897 markWord mark = markWord::prototype().set_narrow_klass(nk);
898 mark = mark.copy_hashctrl_from(orig_mirror->mark());
899 if (mark.is_hashed_not_expanded()) {
900 scratch_m->set_mark(scratch_m->initialize_hash_if_necessary(orig_mirror, orig_klass, mark));
901 } else {
902 assert(mark.is_hashed_expanded(), "must be hashed & moved");
903 int offset = orig_klass->hash_offset_in_bytes(orig_mirror, mark);
904 assert(offset >= 4, "hash offset must not be in header");
905 scratch_m->int_field_put(offset, (jint) src_hash);
906 scratch_m->set_mark(mark);
907 }
908 assert(scratch_m->mark().is_hashed_expanded(), "must be hashed & moved");
909 assert(scratch_m->mark().is_not_hashed_expanded() || scratch_m->mark().is_hashed_expanded(), "must be not hashed and expanded");
910 } else {
911 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
912 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
913 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
914 }
915 assert(scratch_m->mark().is_unlocked(), "sanity");
916 }
917
918 if (CDSConfig::is_dumping_aot_linked_classes()) {
919 java_lang_Class::set_module(scratch_m, java_lang_Class::module(orig_mirror));
920 java_lang_Class::set_protection_domain(scratch_m, java_lang_Class::protection_domain(orig_mirror));
921 }
922 }
923
924 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
925 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
926 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
927 if (rr != nullptr && !HeapShared::is_too_large_to_archive(rr)) {
928 return HeapShared::scratch_resolved_references(src_ik->constants());
929 }
930 }
931 return nullptr;
932 }
933
934 int HeapShared::archive_exception_instance(oop exception) {
935 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
936 assert(success, "sanity");
937 return append_root(exception);
938 }
939
940 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
941 OopHandle oh(&src_obj);
942 CachedOopInfo* info = archived_object_cache()->get(oh);
943 assert(info != nullptr, "must be");
944 has_oop_pointers = info->has_oop_pointers();
945 has_native_pointers = info->has_native_pointers();
946 }
947
948 void HeapShared::set_has_native_pointers(oop src_obj) {
949 OopHandle oh(&src_obj);
950 CachedOopInfo* info = archived_object_cache()->get(oh);
951 assert(info != nullptr, "must be");
952 info->set_has_native_pointers();
953 }
954
955 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
956 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
957 void HeapShared::start_scanning_for_oops() {
958 {
959 NoSafepointVerifier nsv;
960
961 // The special subgraph doesn't belong to any class. We use Object_klass() here just
962 // for convenience.
963 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass());
964
965 // Cache for recording where the archived objects are copied to
966 create_archived_object_cache();
967
968 if (HeapShared::is_writing_mapping_mode() && (UseG1GC || UseCompressedOops)) {
969 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
970 UseCompressedOops ? p2i(CompressedOops::begin()) :
971 p2i((address)G1CollectedHeap::heap()->reserved().start()),
972 UseCompressedOops ? p2i(CompressedOops::end()) :
973 p2i((address)G1CollectedHeap::heap()->reserved().end()));
974 }
975
976 archive_subgraphs();
977 }
978
979 init_seen_objects_table();
980 Universe::archive_exception_instances();
981 }
982
983 void HeapShared::end_scanning_for_oops() {
984 if (is_writing_mapping_mode()) {
985 StringTable::init_shared_table();
986 }
987 delete_seen_objects_table();
988 }
989
990 void HeapShared::write_heap(AOTMappedHeapInfo* mapped_heap_info, AOTStreamedHeapInfo* streamed_heap_info) {
991 {
992 NoSafepointVerifier nsv;
993 CDSHeapVerifier::verify();
994 check_special_subgraph_classes();
995 }
996
997 if (HeapShared::is_writing_mapping_mode()) {
998 StringTable::write_shared_table();
999 AOTMappedHeapWriter::write(_pending_roots, mapped_heap_info);
1000 } else {
1001 assert(HeapShared::is_writing_streaming_mode(), "are there more modes?");
1002 AOTStreamedHeapWriter::write(_pending_roots, streamed_heap_info);
1003 }
1004
1005 ArchiveBuilder::OtherROAllocMark mark;
1006 write_subgraph_info_table();
1007
1008 DEBUG_ONLY(_runtime_classes_with_cached_oops = _dumptime_classes_with_cached_oops->write_ordered_array());
1009
1010 delete _pending_roots;
1011 _pending_roots = nullptr;
1012
1013 make_archived_object_cache_gc_safe();
1014 }
1015
1016 void HeapShared::scan_java_mirror(oop orig_mirror) {
1017 oop m = scratch_java_mirror(orig_mirror);
1018 if (m != nullptr) { // nullptr if for custom class loader
1019 copy_java_mirror(orig_mirror, m);
1020 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
1021 assert(success, "sanity");
1022 }
1023 }
1024
1025 void HeapShared::scan_java_class(Klass* orig_k) {
1026 scan_java_mirror(orig_k->java_mirror());
1027
1028 if (orig_k->is_instance_klass()) {
1029 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
1030 orig_ik->constants()->prepare_resolved_references_for_archiving();
1031 objArrayOop rr = get_archived_resolved_references(orig_ik);
1032 if (rr != nullptr) {
1033 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
1034 assert(success, "must be");
1035 }
1036 }
1037 }
1038
1039 void HeapShared::archive_subgraphs() {
1040 assert(CDSConfig::is_dumping_heap(), "must be");
1041
1042 if (CDSConfig::is_dumping_klass_subgraphs()) {
1043 archive_object_subgraphs(archive_subgraph_entry_fields);
1044 }
1045 }
1046
1047 //
1048 // Subgraph archiving support
1049 //
1050 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
1051 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
1052
1053 // Get the subgraph_info for Klass k. A new subgraph_info is created if
1054 // there is no existing one for k. The subgraph_info records the "buffered"
1055 // address of the class.
1056 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k) {
1057 assert(CDSConfig::is_dumping_heap(), "dump time only");
1058 bool created;
1059 KlassSubGraphInfo* info =
1060 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k), &created);
1061 assert(created, "must not initialize twice");
1062 return info;
1063 }
1064
1065 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
1066 assert(CDSConfig::is_dumping_heap(), "dump time only");
1067 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
1068 assert(info != nullptr, "must have been initialized");
1069 return info;
1070 }
1071
1072 // Add an entry field to the current KlassSubGraphInfo.
1073 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
1074 assert(CDSConfig::is_dumping_heap(), "dump time only");
1075 if (_subgraph_entry_fields == nullptr) {
1076 _subgraph_entry_fields =
1077 new (mtClass) GrowableArray<int>(10, mtClass);
1078 }
1079 _subgraph_entry_fields->append(static_field_offset);
1080 _subgraph_entry_fields->append(HeapShared::append_root(v));
1081 }
1082
1083 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
1084 // Only objects of boot classes can be included in sub-graph.
1085 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
1086 assert(CDSConfig::is_dumping_heap(), "dump time only");
1087
1088 if (_subgraph_object_klasses == nullptr) {
1089 _subgraph_object_klasses =
1090 new (mtClass) GrowableArray<Klass*>(50, mtClass);
1091 }
1092
1093 if (_k == orig_k) {
1094 // Don't add the Klass containing the sub-graph to it's own klass
1095 // initialization list.
1096 return;
1097 }
1098
1099 if (orig_k->is_instance_klass()) {
1100 #ifdef ASSERT
1101 InstanceKlass* ik = InstanceKlass::cast(orig_k);
1102 if (CDSConfig::is_dumping_method_handles()) {
1103 // -XX:AOTInitTestClass must be used carefully in regression tests to
1104 // include only classes that are safe to aot-initialize.
1105 assert(ik->class_loader() == nullptr ||
1106 HeapShared::is_lambda_proxy_klass(ik) ||
1107 AOTClassInitializer::has_test_class(),
1108 "we can archive only instances of boot classes or lambda proxy classes");
1109 } else {
1110 assert(ik->class_loader() == nullptr, "must be boot class");
1111 }
1112 #endif
1113 // vmClasses::xxx_klass() are not updated, need to check
1114 // the original Klass*
1115 if (orig_k == vmClasses::String_klass() ||
1116 orig_k == vmClasses::Object_klass()) {
1117 // Initialized early during VM initialization. No need to be added
1118 // to the sub-graph object class list.
1119 return;
1120 }
1121 check_allowed_klass(InstanceKlass::cast(orig_k));
1122 } else if (orig_k->is_objArray_klass()) {
1123 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
1124 if (abk->is_instance_klass()) {
1125 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
1126 "must be boot class");
1127 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
1128 }
1129 if (orig_k == Universe::objectArrayKlass()) {
1130 // Initialized early during Universe::genesis. No need to be added
1131 // to the list.
1132 return;
1133 }
1134 } else {
1135 assert(orig_k->is_typeArray_klass(), "must be");
1136 // Primitive type arrays are created early during Universe::genesis.
1137 return;
1138 }
1139
1140 if (log_is_enabled(Debug, aot, heap)) {
1141 if (!_subgraph_object_klasses->contains(orig_k)) {
1142 ResourceMark rm;
1143 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
1144 }
1145 }
1146
1147 _subgraph_object_klasses->append_if_missing(orig_k);
1148 }
1149
1150 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
1151 #ifndef PRODUCT
1152 if (AOTClassInitializer::has_test_class()) {
1153 // The tests can cache arbitrary types of objects.
1154 return;
1155 }
1156 #endif
1157
1158 if (ik->module()->name() == vmSymbols::java_base()) {
1159 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
1160 return;
1161 }
1162
1163 const char* lambda_msg = "";
1164 if (CDSConfig::is_dumping_method_handles()) {
1165 lambda_msg = ", or a lambda proxy class";
1166 if (HeapShared::is_lambda_proxy_klass(ik) &&
1167 (ik->class_loader() == nullptr ||
1168 ik->class_loader() == SystemDictionary::java_platform_loader() ||
1169 ik->class_loader() == SystemDictionary::java_system_loader())) {
1170 return;
1171 }
1172 }
1173
1174 #ifndef PRODUCT
1175 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
1176 // This class is loaded by ArchiveHeapTestClass
1177 return;
1178 }
1179 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
1180 #else
1181 const char* testcls_msg = "";
1182 #endif
1183
1184 ResourceMark rm;
1185 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
1186 ik->external_name(), lambda_msg, testcls_msg);
1187 AOTMetaspace::unrecoverable_writing_error();
1188 }
1189
1190 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
1191 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
1192 _k = ArchiveBuilder::get_buffered_klass(info->klass());
1193 _entry_field_records = nullptr;
1194 _subgraph_object_klasses = nullptr;
1195
1196 // populate the entry fields
1197 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
1198 if (entry_fields != nullptr) {
1199 int num_entry_fields = entry_fields->length();
1200 assert(num_entry_fields % 2 == 0, "sanity");
1201 _entry_field_records =
1202 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
1203 for (int i = 0 ; i < num_entry_fields; i++) {
1204 _entry_field_records->at_put(i, entry_fields->at(i));
1205 }
1206 }
1207
1208 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
1209 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
1210 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
1211 if (recorded_klasses != nullptr) {
1212 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
1213 // programmatically loading a subgraph, we only need to explicitly initialize the classes
1214 // that are not aot-inited.
1215 int num_to_copy = 0;
1216 for (int i = 0; i < recorded_klasses->length(); i++) {
1217 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1218 if (!subgraph_k->has_aot_initialized_mirror()) {
1219 num_to_copy ++;
1220 }
1221 }
1222
1223 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
1224 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
1225 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
1226 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1227 if (subgraph_k->has_aot_initialized_mirror()) {
1228 continue;
1229 }
1230 if (log_is_enabled(Info, aot, heap)) {
1231 ResourceMark rm;
1232 const char* owner_name = is_special ? "<special>" : _k->external_name();
1233 if (subgraph_k->is_instance_klass()) {
1234 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
1235 }
1236 log_info(aot, heap)(
1237 "Archived object klass %s (%2d) => %s",
1238 owner_name, n, subgraph_k->external_name());
1239 }
1240 _subgraph_object_klasses->at_put(n, subgraph_k);
1241 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
1242 n++;
1243 }
1244 }
1245
1246 ArchivePtrMarker::mark_pointer(&_k);
1247 ArchivePtrMarker::mark_pointer(&_entry_field_records);
1248 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
1249 }
1250
1251 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
1252 CompactHashtableWriter* _writer;
1253 public:
1254 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
1255
1256 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
1257 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
1258 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
1259 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
1260 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
1261 _writer->add(hash, AOTCompressedPointers::encode_not_null(record));
1262 }
1263 return true; // keep on iterating
1264 }
1265 };
1266
1267 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
1268 ArchivedKlassSubGraphInfoRecord* record =
1269 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
1270 record->init(info);
1271 if (info == _dump_time_special_subgraph) {
1272 _run_time_special_subgraph = record;
1273 }
1274 return record;
1275 }
1276
1277 // Build the records of archived subgraph infos, which include:
1278 // - Entry points to all subgraphs from the containing class mirror. The entry
1279 // points are static fields in the mirror. For each entry point, the field
1280 // offset, and value are recorded in the sub-graph
1281 // info. The value is stored back to the corresponding field at runtime.
1282 // - A list of klasses that need to be loaded/initialized before archived
1283 // java object sub-graph can be accessed at runtime.
1284 void HeapShared::write_subgraph_info_table() {
1285 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1286 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1287 CompactHashtableStats stats;
1288
1289 _run_time_subgraph_info_table.reset();
1290
1291 CompactHashtableWriter writer(d_table->number_of_entries(), &stats);
1292 CopyKlassSubGraphInfoToArchive copy(&writer);
1293 d_table->iterate(©);
1294 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1295
1296 #ifndef PRODUCT
1297 if (ArchiveHeapTestClass != nullptr) {
1298 size_t len = strlen(ArchiveHeapTestClass) + 1;
1299 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1300 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1301 _archived_ArchiveHeapTestClass = array;
1302 }
1303 #endif
1304 if (log_is_enabled(Info, aot, heap)) {
1305 print_stats();
1306 }
1307 }
1308
1309 void HeapShared::serialize_tables(SerializeClosure* soc) {
1310
1311 #ifndef PRODUCT
1312 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1313 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1314 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1315 setup_test_class(_test_class_name);
1316 }
1317 #endif
1318
1319 _run_time_subgraph_info_table.serialize_header(soc);
1320 soc->do_ptr(&_run_time_special_subgraph);
1321 DEBUG_ONLY(soc->do_ptr(&_runtime_classes_with_cached_oops));
1322 }
1323
1324 static void verify_the_heap(Klass* k, const char* which) {
1325 if (VerifyArchivedFields > 0) {
1326 ResourceMark rm;
1327 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1328 which, k->external_name());
1329
1330 if (VerifyArchivedFields == 1) {
1331 VM_Verify verify_op;
1332 VMThread::execute(&verify_op);
1333 } else if (VerifyArchivedFields == 2 && is_init_completed()) {
1334 // At this time, the oop->klass() of some archived objects in the heap may not
1335 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1336 // have enough information (object size, oop maps, etc) so that a GC can be safely
1337 // performed.
1338 //
1339 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1340 // to check for GC safety.
1341 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1342 which, k->external_name());
1343 FlagSetting fs1(VerifyBeforeGC, true);
1344 FlagSetting fs2(VerifyDuringGC, true);
1345 FlagSetting fs3(VerifyAfterGC, true);
1346 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1347 }
1348 }
1349 }
1350
1351 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1352 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1353 void HeapShared::resolve_classes(JavaThread* current) {
1354 assert(CDSConfig::is_using_archive(), "runtime only!");
1355 if (CDSConfig::is_using_klass_subgraphs()) {
1356 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1357 }
1358 }
1359
1360 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1361 for (int i = 0; fields[i].valid(); i++) {
1362 ArchivableStaticFieldInfo* info = &fields[i];
1363 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1364 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1365 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1366 resolve_classes_for_subgraph_of(current, k);
1367 }
1368 }
1369
1370 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1371 JavaThread* THREAD = current;
1372 ExceptionMark em(THREAD);
1373 const ArchivedKlassSubGraphInfoRecord* record =
1374 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1375 if (HAS_PENDING_EXCEPTION) {
1376 CLEAR_PENDING_EXCEPTION;
1377 }
1378 if (record == nullptr) {
1379 clear_archived_roots_of(k);
1380 }
1381 }
1382
1383 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1384 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1385 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1386 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1387 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1388 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1389 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1390 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1391 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1392 }
1393 }
1394
1395 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1396 // - interned strings
1397 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1398 // - ConstantPool::resolved_references()
1399 // - Universe::<xxx>_exception_instance()
1400 //
1401 // For example, if this enum class is initialized at AOT cache assembly time:
1402 //
1403 // enum Fruit {
1404 // APPLE, ORANGE, BANANA;
1405 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1406 // }
1407 //
1408 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1409 // should be initialized before any Java code can access the Fruit class. Note that
1410 // HashSet itself doesn't necessary need to be an aot-initialized class.
1411 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1412 if (!is_archived_heap_in_use()) {
1413 return;
1414 }
1415
1416 assert( _run_time_special_subgraph != nullptr, "must be");
1417 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1418 if (klasses != nullptr) {
1419 for (int pass = 0; pass < 2; pass ++) {
1420 for (int i = 0; i < klasses->length(); i++) {
1421 Klass* k = klasses->at(i);
1422 if (k->class_loader_data() == nullptr) {
1423 // This class is not yet loaded. We will initialize it in a later phase.
1424 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1425 // but k is part of AOTLinkedClassCategory::BOOT2.
1426 continue;
1427 }
1428 if (k->class_loader() == class_loader()) {
1429 if (pass == 0) {
1430 if (k->is_instance_klass()) {
1431 InstanceKlass::cast(k)->link_class(CHECK);
1432 }
1433 } else {
1434 resolve_or_init(k, /*do_init*/true, CHECK);
1435 }
1436 }
1437 }
1438 }
1439 }
1440 }
1441
1442 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1443 JavaThread* THREAD = current;
1444 if (!CDSConfig::is_using_klass_subgraphs()) {
1445 return; // nothing to do
1446 }
1447
1448 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1449 !CDSConfig::is_using_optimized_module_handling() &&
1450 // archive was created with --module-path
1451 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1452 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1453 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1454 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1455 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1456 AOTClassLocationConfig::runtime()->num_module_paths());
1457 return;
1458 }
1459
1460 ExceptionMark em(THREAD);
1461 const ArchivedKlassSubGraphInfoRecord* record =
1462 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1463
1464 if (HAS_PENDING_EXCEPTION) {
1465 CLEAR_PENDING_EXCEPTION;
1466 // None of the field value will be set if there was an exception when initializing the classes.
1467 // The java code will not see any of the archived objects in the
1468 // subgraphs referenced from k in this case.
1469 return;
1470 }
1471
1472 if (record != nullptr) {
1473 init_archived_fields_for(k, record);
1474 }
1475 }
1476
1477 const ArchivedKlassSubGraphInfoRecord*
1478 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1479 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1480
1481 if (!k->in_aot_cache()) {
1482 return nullptr;
1483 }
1484 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1485 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1486
1487 #ifndef PRODUCT
1488 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1489 _test_class = k;
1490 _test_class_record = record;
1491 }
1492 #endif
1493
1494 // Initialize from archived data. Currently this is done only
1495 // during VM initialization time. No lock is needed.
1496 if (record == nullptr) {
1497 if (log_is_enabled(Info, aot, heap)) {
1498 ResourceMark rm(THREAD);
1499 log_info(aot, heap)("subgraph %s is not recorded",
1500 k->external_name());
1501 }
1502 return nullptr;
1503 } else {
1504 if (log_is_enabled(Info, aot, heap)) {
1505 ResourceMark rm;
1506 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1507 }
1508
1509 resolve_or_init(k, do_init, CHECK_NULL);
1510
1511 // Load/link/initialize the klasses of the objects in the subgraph.
1512 // nullptr class loader is used.
1513 Array<Klass*>* klasses = record->subgraph_object_klasses();
1514 if (klasses != nullptr) {
1515 for (int i = 0; i < klasses->length(); i++) {
1516 Klass* klass = klasses->at(i);
1517 if (!klass->in_aot_cache()) {
1518 return nullptr;
1519 }
1520 resolve_or_init(klass, do_init, CHECK_NULL);
1521 }
1522 }
1523 }
1524
1525 return record;
1526 }
1527
1528 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1529 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1530 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1531 if (k == nullptr) {
1532 return;
1533 }
1534 assert(k->defined_by_boot_loader(), "sanity");
1535 resolve_or_init(k, false, CHECK);
1536 if (do_init) {
1537 resolve_or_init(k, true, CHECK);
1538 }
1539 }
1540
1541 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1542 if (!do_init) {
1543 if (k->class_loader_data() == nullptr) {
1544 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1545 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1546 }
1547 } else {
1548 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1549 if (k->is_instance_klass()) {
1550 InstanceKlass* ik = InstanceKlass::cast(k);
1551 ik->initialize(CHECK);
1552 } else if (k->is_objArray_klass()) {
1553 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1554 oak->initialize(CHECK);
1555 }
1556 }
1557 }
1558
1559 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1560 verify_the_heap(k, "before");
1561
1562 Array<int>* entry_field_records = record->entry_field_records();
1563 if (entry_field_records != nullptr) {
1564 int efr_len = entry_field_records->length();
1565 assert(efr_len % 2 == 0, "sanity");
1566 for (int i = 0; i < efr_len; i += 2) {
1567 int field_offset = entry_field_records->at(i);
1568 int root_index = entry_field_records->at(i+1);
1569 // Load the subgraph entry fields from the record and store them back to
1570 // the corresponding fields within the mirror.
1571 oop v = get_root(root_index, /*clear=*/true);
1572 oop m = k->java_mirror();
1573 if (k->has_aot_initialized_mirror()) {
1574 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1575 } else {
1576 m->obj_field_put(field_offset, v);
1577 }
1578 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1579 }
1580
1581 // Done. Java code can see the archived sub-graphs referenced from k's
1582 // mirror after this point.
1583 if (log_is_enabled(Info, aot, heap)) {
1584 ResourceMark rm;
1585 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s",
1586 k->external_name(), p2i(k),
1587 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1588 }
1589 }
1590
1591 verify_the_heap(k, "after ");
1592 }
1593
1594 void HeapShared::clear_archived_roots_of(Klass* k) {
1595 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1596 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1597 if (record != nullptr) {
1598 Array<int>* entry_field_records = record->entry_field_records();
1599 if (entry_field_records != nullptr) {
1600 int efr_len = entry_field_records->length();
1601 assert(efr_len % 2 == 0, "sanity");
1602 for (int i = 0; i < efr_len; i += 2) {
1603 int root_index = entry_field_records->at(i+1);
1604 clear_root(root_index);
1605 }
1606 }
1607 }
1608 }
1609
1610 // Push all oop fields (or oop array elemenets in case of an objArray) in
1611 // _referencing_obj onto the _stack.
1612 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1613 PendingOopStack* _stack;
1614 GrowableArray<oop> _found_oop_fields;
1615 int _level;
1616 bool _record_klasses_only;
1617 KlassSubGraphInfo* _subgraph_info;
1618 oop _referencing_obj;
1619 bool _is_java_lang_ref;
1620 public:
1621 OopFieldPusher(PendingOopStack* stack,
1622 int level,
1623 bool record_klasses_only,
1624 KlassSubGraphInfo* subgraph_info,
1625 oop orig) :
1626 _stack(stack),
1627 _found_oop_fields(),
1628 _level(level),
1629 _record_klasses_only(record_klasses_only),
1630 _subgraph_info(subgraph_info),
1631 _referencing_obj(orig) {
1632 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1633 }
1634 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1635 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1636
1637 ~OopFieldPusher() {
1638 while (_found_oop_fields.length() > 0) {
1639 // This produces the exact same traversal order as the previous version
1640 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1641 // walking the oop fields in _referencing_obj by ascending field offsets.
1642 oop obj = _found_oop_fields.pop();
1643 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1644 }
1645 }
1646
1647 protected:
1648 template <class T> void do_oop_work(T *p) {
1649 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1650 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1651 if (obj != nullptr) {
1652 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1653 // Do not follow these fields. They will be cleared to null.
1654 return;
1655 }
1656
1657 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1658 ResourceMark rm;
1659 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1660 _referencing_obj->klass()->external_name(), field_offset,
1661 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1662 if (log_is_enabled(Trace, aot, heap)) {
1663 LogTarget(Trace, aot, heap) log;
1664 LogStream out(log);
1665 obj->print_on(&out);
1666 }
1667 }
1668
1669 _found_oop_fields.push(obj);
1670 }
1671 }
1672
1673 public:
1674 oop referencing_obj() { return _referencing_obj; }
1675 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1676 };
1677
1678 // Checks if an oop has any non-null oop fields
1679 class PointsToOopsChecker : public BasicOopIterateClosure {
1680 bool _result;
1681
1682 template <class T> void check(T *p) {
1683 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1684 }
1685
1686 public:
1687 PointsToOopsChecker() : _result(false) {}
1688 void do_oop(narrowOop *p) { check(p); }
1689 void do_oop( oop *p) { check(p); }
1690 bool result() { return _result; }
1691 };
1692
1693 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1694 PointsToOopsChecker points_to_oops_checker;
1695 obj->oop_iterate(&points_to_oops_checker);
1696 return CachedOopInfo(OopHandle(Universe::vm_global(), referrer), points_to_oops_checker.result());
1697 }
1698
1699 void HeapShared::init_box_classes(TRAPS) {
1700 if (is_archived_heap_in_use()) {
1701 vmClasses::Boolean_klass()->initialize(CHECK);
1702 vmClasses::Character_klass()->initialize(CHECK);
1703 vmClasses::Float_klass()->initialize(CHECK);
1704 vmClasses::Double_klass()->initialize(CHECK);
1705 vmClasses::Byte_klass()->initialize(CHECK);
1706 vmClasses::Short_klass()->initialize(CHECK);
1707 vmClasses::Integer_klass()->initialize(CHECK);
1708 vmClasses::Long_klass()->initialize(CHECK);
1709 vmClasses::Void_klass()->initialize(CHECK);
1710 }
1711 }
1712
1713 // (1) If orig_obj has not been archived yet, archive it.
1714 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1715 // trace all objects that are reachable from it, and make sure these objects are archived.
1716 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1717 // were already archived when this function is called)
1718 bool HeapShared::archive_reachable_objects_from(int level,
1719 KlassSubGraphInfo* subgraph_info,
1720 oop orig_obj) {
1721 assert(orig_obj != nullptr, "must be");
1722 PendingOopStack stack;
1723 stack.push(PendingOop(orig_obj, nullptr, level));
1724
1725 while (stack.length() > 0) {
1726 PendingOop po = stack.pop();
1727 _object_being_archived = po;
1728 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1729 _object_being_archived = PendingOop();
1730
1731 if (!status) {
1732 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1733 // as the Java code will take care of initializing this field dynamically.
1734 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1735 return false;
1736 }
1737 }
1738
1739 return true;
1740 }
1741
1742 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1743 oop orig_obj, oop referrer) {
1744 assert(orig_obj != nullptr, "must be");
1745 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1746 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1747 // If you get an error here, you probably made a change in the JDK library that has added
1748 // these objects that are referenced (directly or indirectly) by static fields.
1749 ResourceMark rm;
1750 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1751 debug_trace();
1752 AOTMetaspace::unrecoverable_writing_error();
1753 }
1754
1755 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1756 ResourceMark rm;
1757 LogTarget(Debug, aot, heap) log;
1758 LogStream out(log);
1759 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1760 Klass* k = java_lang_Class::as_Klass(orig_obj);
1761 if (k != nullptr) {
1762 out.print("%s", k->external_name());
1763 } else {
1764 out.print("primitive");
1765 }
1766 out.print_cr("; scratch mirror = " PTR_FORMAT,
1767 p2i(scratch_java_mirror(orig_obj)));
1768 }
1769
1770 if (java_lang_Class::is_instance(orig_obj)) {
1771 orig_obj = RegeneratedClasses::maybe_get_regenerated_mirror(orig_obj);
1772 }
1773
1774 if (CDSConfig::is_dumping_aot_linked_classes()) {
1775 if (java_lang_Class::is_instance(orig_obj)) {
1776 orig_obj = scratch_java_mirror(orig_obj);
1777 assert(orig_obj != nullptr, "must be archived");
1778 }
1779 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1780 // Without CDSConfig::is_dumping_aot_linked_classes(), we only allow archived objects to
1781 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1782 // very early by HeapShared::init_box_classes().
1783 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1784 || java_lang_Class::is_primitive(orig_obj)
1785 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1786 || orig_obj == vmClasses::Character_klass()->java_mirror()
1787 || orig_obj == vmClasses::Float_klass()->java_mirror()
1788 || orig_obj == vmClasses::Double_klass()->java_mirror()
1789 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1790 || orig_obj == vmClasses::Short_klass()->java_mirror()
1791 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1792 || orig_obj == vmClasses::Long_klass()->java_mirror()
1793 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1794 orig_obj = scratch_java_mirror(orig_obj);
1795 assert(orig_obj != nullptr, "must be archived");
1796 } else {
1797 // If you get an error here, you probably made a change in the JDK library that has added a Class
1798 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1799 // defined at the top of this file.
1800 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1801 debug_trace();
1802 AOTMetaspace::unrecoverable_writing_error();
1803 }
1804 }
1805
1806 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1807 // orig_obj has already been archived and traced. Nothing more to do.
1808 return true;
1809 } else {
1810 set_has_been_seen_during_subgraph_recording(orig_obj);
1811 }
1812
1813 bool already_archived = has_been_archived(orig_obj);
1814 bool record_klasses_only = already_archived;
1815 if (!already_archived) {
1816 ++_num_new_archived_objs;
1817 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1818 // Skip archiving the sub-graph referenced from the current entry field.
1819 ResourceMark rm;
1820 log_error(aot, heap)(
1821 "Cannot archive the sub-graph referenced from %s object ("
1822 PTR_FORMAT ") size %zu, skipped.",
1823 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1824 if (level == 1) {
1825 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1826 // as the Java code will take care of initializing this field dynamically.
1827 return false;
1828 } else {
1829 // We don't know how to handle an object that has been archived, but some of its reachable
1830 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1831 // we have a real use case.
1832 AOTMetaspace::unrecoverable_writing_error();
1833 }
1834 }
1835 }
1836
1837 Klass *orig_k = orig_obj->klass();
1838 subgraph_info->add_subgraph_object_klass(orig_k);
1839
1840 {
1841 // Find all the oops that are referenced by orig_obj, push them onto the stack
1842 // so we can work on them next.
1843 ResourceMark rm;
1844 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1845 orig_obj->oop_iterate(&pusher);
1846 }
1847
1848 if (CDSConfig::is_dumping_aot_linked_classes()) {
1849 // The enum klasses are archived with aot-initialized mirror.
1850 // See AOTClassInitializer::can_archive_initialized_mirror().
1851 } else {
1852 // This is legacy support for enum classes before JEP 483 -- we cannot rerun
1853 // the enum's <clinit> in the production run, so special handling is needed.
1854 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1855 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1856 }
1857 }
1858
1859 return true;
1860 }
1861
1862 //
1863 // Start from the given static field in a java mirror and archive the
1864 // complete sub-graph of java heap objects that are reached directly
1865 // or indirectly from the starting object by following references.
1866 // Sub-graph archiving restrictions (current):
1867 //
1868 // - All classes of objects in the archived sub-graph (including the
1869 // entry class) must be boot class only.
1870 // - No java.lang.Class instance (java mirror) can be included inside
1871 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1872 //
1873 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1874 //
1875 // 1) Java object sub-graph archiving starts from a given static field
1876 // within a Class instance (java mirror). If the static field is a
1877 // reference field and points to a non-null java object, proceed to
1878 // the next step.
1879 //
1880 // 2) Archives the referenced java object. If an archived copy of the
1881 // current object already exists, updates the pointer in the archived
1882 // copy of the referencing object to point to the current archived object.
1883 // Otherwise, proceed to the next step.
1884 //
1885 // 3) Follows all references within the current java object and recursively
1886 // archive the sub-graph of objects starting from each reference.
1887 //
1888 // 4) Updates the pointer in the archived copy of referencing object to
1889 // point to the current archived object.
1890 //
1891 // 5) The Klass of the current java object is added to the list of Klasses
1892 // for loading and initializing before any object in the archived graph can
1893 // be accessed at runtime.
1894 //
1895 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1896 const char* klass_name,
1897 int field_offset,
1898 const char* field_name) {
1899 precond(CDSConfig::is_dumping_klass_subgraphs());
1900 assert(k->defined_by_boot_loader(), "must be boot class");
1901
1902 oop m = k->java_mirror();
1903
1904 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1905 oop f = m->obj_field(field_offset);
1906
1907 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1908
1909 if (!CompressedOops::is_null(f)) {
1910 if (log_is_enabled(Trace, aot, heap)) {
1911 LogTarget(Trace, aot, heap) log;
1912 LogStream out(log);
1913 f->print_on(&out);
1914 }
1915
1916 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1917 if (!success) {
1918 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1919 klass_name, field_name);
1920 } else {
1921 // Note: the field value is not preserved in the archived mirror.
1922 // Record the field as a new subGraph entry point. The recorded
1923 // information is restored from the archive at runtime.
1924 subgraph_info->add_subgraph_entry_field(field_offset, f);
1925 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1926 }
1927 } else {
1928 // The field contains null, we still need to record the entry point,
1929 // so it can be restored at runtime.
1930 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1931 }
1932 }
1933
1934 #ifndef PRODUCT
1935 class VerifySharedOopClosure: public BasicOopIterateClosure {
1936 public:
1937 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1938 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1939
1940 protected:
1941 template <class T> void do_oop_work(T *p) {
1942 oop obj = HeapAccess<>::oop_load(p);
1943 if (obj != nullptr) {
1944 HeapShared::verify_reachable_objects_from(obj);
1945 }
1946 }
1947 };
1948
1949 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1950 precond(CDSConfig::is_dumping_klass_subgraphs());
1951 assert(k->defined_by_boot_loader(), "must be boot class");
1952
1953 oop m = k->java_mirror();
1954 oop f = m->obj_field(field_offset);
1955 if (!CompressedOops::is_null(f)) {
1956 verify_subgraph_from(f);
1957 }
1958 }
1959
1960 void HeapShared::verify_subgraph_from(oop orig_obj) {
1961 if (!has_been_archived(orig_obj)) {
1962 // It's OK for the root of a subgraph to be not archived. See comments in
1963 // archive_reachable_objects_from().
1964 return;
1965 }
1966
1967 // Verify that all objects reachable from orig_obj are archived.
1968 init_seen_objects_table();
1969 verify_reachable_objects_from(orig_obj);
1970 delete_seen_objects_table();
1971 }
1972
1973 void HeapShared::verify_reachable_objects_from(oop obj) {
1974 _num_total_verifications ++;
1975 if (java_lang_Class::is_instance(obj)) {
1976 obj = RegeneratedClasses::maybe_get_regenerated_mirror(obj);
1977 obj = scratch_java_mirror(obj);
1978 assert(obj != nullptr, "must be");
1979 }
1980 if (!has_been_seen_during_subgraph_recording(obj)) {
1981 set_has_been_seen_during_subgraph_recording(obj);
1982 assert(has_been_archived(obj), "must be");
1983 VerifySharedOopClosure walker;
1984 obj->oop_iterate(&walker);
1985 }
1986 }
1987 #endif
1988
1989 void HeapShared::check_special_subgraph_classes() {
1990 if (CDSConfig::is_dumping_aot_linked_classes()) {
1991 // We can have aot-initialized classes (such as Enums) that can reference objects
1992 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
1993 // aot-initialize classes that are "safe".
1994 //
1995 // TODO: we need an automatic tool that checks the safety of aot-initialized
1996 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
1997 return;
1998 } else {
1999 // In this case, the special subgraph should contain a few specific types
2000 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
2001 int num = klasses->length();
2002 for (int i = 0; i < num; i++) {
2003 Klass* subgraph_k = klasses->at(i);
2004 Symbol* name = subgraph_k->name();
2005 if (subgraph_k->is_instance_klass() &&
2006 name != vmSymbols::java_lang_Class() &&
2007 name != vmSymbols::java_lang_String() &&
2008 name != vmSymbols::java_lang_ArithmeticException() &&
2009 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
2010 name != vmSymbols::java_lang_ArrayStoreException() &&
2011 name != vmSymbols::java_lang_ClassCastException() &&
2012 name != vmSymbols::java_lang_InternalError() &&
2013 name != vmSymbols::java_lang_NullPointerException() &&
2014 name != vmSymbols::jdk_internal_vm_PreemptedException()) {
2015 ResourceMark rm;
2016 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
2017 }
2018 }
2019 }
2020 }
2021
2022 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
2023 HeapShared::PendingOop HeapShared::_object_being_archived;
2024 size_t HeapShared::_num_new_walked_objs;
2025 size_t HeapShared::_num_new_archived_objs;
2026 size_t HeapShared::_num_old_recorded_klasses;
2027
2028 size_t HeapShared::_num_total_subgraph_recordings = 0;
2029 size_t HeapShared::_num_total_walked_objs = 0;
2030 size_t HeapShared::_num_total_archived_objs = 0;
2031 size_t HeapShared::_num_total_recorded_klasses = 0;
2032 size_t HeapShared::_num_total_verifications = 0;
2033
2034 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
2035 return _seen_objects_table->get(obj) != nullptr;
2036 }
2037
2038 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
2039 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
2040 _seen_objects_table->put_when_absent(obj, true);
2041 _seen_objects_table->maybe_grow();
2042 ++ _num_new_walked_objs;
2043 }
2044
2045 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name) {
2046 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
2047 init_subgraph_info(k);
2048 init_seen_objects_table();
2049 _num_new_walked_objs = 0;
2050 _num_new_archived_objs = 0;
2051 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
2052 }
2053
2054 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
2055 size_t num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
2056 _num_old_recorded_klasses;
2057 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
2058 "walked %zu objs, archived %zu new objs, recorded %zu classes",
2059 class_name, _num_new_walked_objs, _num_new_archived_objs,
2060 num_new_recorded_klasses);
2061
2062 delete_seen_objects_table();
2063
2064 _num_total_subgraph_recordings ++;
2065 _num_total_walked_objs += _num_new_walked_objs;
2066 _num_total_archived_objs += _num_new_archived_objs;
2067 _num_total_recorded_klasses += num_new_recorded_klasses;
2068 }
2069
2070 class ArchivableStaticFieldFinder: public FieldClosure {
2071 InstanceKlass* _ik;
2072 Symbol* _field_name;
2073 bool _found;
2074 int _offset;
2075 public:
2076 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
2077 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
2078
2079 virtual void do_field(fieldDescriptor* fd) {
2080 if (fd->name() == _field_name) {
2081 assert(!_found, "fields can never be overloaded");
2082 if (is_reference_type(fd->field_type())) {
2083 _found = true;
2084 _offset = fd->offset();
2085 }
2086 }
2087 }
2088 bool found() { return _found; }
2089 int offset() { return _offset; }
2090 };
2091
2092 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
2093 TRAPS) {
2094 for (int i = 0; fields[i].valid(); i++) {
2095 ArchivableStaticFieldInfo* info = &fields[i];
2096 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
2097 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
2098 ResourceMark rm; // for stringStream::as_string() etc.
2099
2100 #ifndef PRODUCT
2101 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
2102 const char* test_class_name = ArchiveHeapTestClass;
2103 #else
2104 bool is_test_class = false;
2105 const char* test_class_name = ""; // avoid C++ printf checks warnings.
2106 #endif
2107
2108 if (is_test_class) {
2109 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
2110 }
2111
2112 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
2113 if (HAS_PENDING_EXCEPTION) {
2114 CLEAR_PENDING_EXCEPTION;
2115 stringStream st;
2116 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
2117 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2118 }
2119
2120 if (!k->is_instance_klass()) {
2121 stringStream st;
2122 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
2123 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2124 }
2125
2126 InstanceKlass* ik = InstanceKlass::cast(k);
2127 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
2128 "Only support boot classes");
2129
2130 if (is_test_class) {
2131 if (ik->module()->is_named()) {
2132 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
2133 // core-lib classes. You need to at least append to the bootclasspath.
2134 stringStream st;
2135 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
2136 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2137 }
2138
2139 if (ik->package() != nullptr) {
2140 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
2141 stringStream st;
2142 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
2143 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2144 }
2145 } else {
2146 if (ik->module()->name() != vmSymbols::java_base()) {
2147 // We don't want to deal with cases when a module is unavailable at runtime.
2148 // FUTURE -- load from archived heap only when module graph has not changed
2149 // between dump and runtime.
2150 stringStream st;
2151 st.print("%s is not in java.base module", info->klass_name);
2152 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2153 }
2154 }
2155
2156 if (is_test_class) {
2157 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
2158 }
2159 ik->initialize(CHECK);
2160
2161 ArchivableStaticFieldFinder finder(ik, field_name);
2162 ik->do_local_static_fields(&finder);
2163 if (!finder.found()) {
2164 stringStream st;
2165 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
2166 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2167 }
2168
2169 info->klass = ik;
2170 info->offset = finder.offset();
2171 }
2172 }
2173
2174 void HeapShared::init_subgraph_entry_fields(TRAPS) {
2175 assert(CDSConfig::is_dumping_heap(), "must be");
2176 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
2177 if (CDSConfig::is_dumping_klass_subgraphs()) {
2178 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
2179 }
2180 }
2181
2182 #ifndef PRODUCT
2183 void HeapShared::setup_test_class(const char* test_class_name) {
2184 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
2185 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
2186 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
2187 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
2188
2189 if (test_class_name != nullptr) {
2190 p[num_slots - 2].klass_name = test_class_name;
2191 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
2192 }
2193 }
2194
2195 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
2196 // during runtime. This may be called before the module system is initialized so
2197 // we cannot rely on InstanceKlass::module(), etc.
2198 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
2199 if (_test_class != nullptr) {
2200 if (ik == _test_class) {
2201 return true;
2202 }
2203 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
2204 if (klasses == nullptr) {
2205 return false;
2206 }
2207
2208 for (int i = 0; i < klasses->length(); i++) {
2209 Klass* k = klasses->at(i);
2210 if (k == ik) {
2211 Symbol* name;
2212 if (k->is_instance_klass()) {
2213 name = InstanceKlass::cast(k)->name();
2214 } else if (k->is_objArray_klass()) {
2215 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
2216 if (!bk->is_instance_klass()) {
2217 return false;
2218 }
2219 name = bk->name();
2220 } else {
2221 return false;
2222 }
2223
2224 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
2225 // to be:
2226 // (A) java.base classes (which must not be in the unnamed module)
2227 // (B) test classes which must be in the unnamed package of the unnamed module.
2228 // So if we see a '/' character in the class name, it must be in (A);
2229 // otherwise it must be in (B).
2230 if (name->index_of_at(0, "/", 1) >= 0) {
2231 return false; // (A)
2232 }
2233
2234 return true; // (B)
2235 }
2236 }
2237 }
2238
2239 return false;
2240 }
2241
2242 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2243 Klass* k = _test_class;
2244 if (k != nullptr && is_archived_heap_in_use()) {
2245 JavaThread* THREAD = current;
2246 ExceptionMark em(THREAD);
2247 const ArchivedKlassSubGraphInfoRecord* record =
2248 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2249
2250 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2251 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2252 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2253 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2254 if (record != nullptr) {
2255 init_archived_fields_for(k, record);
2256 }
2257 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2258 }
2259 }
2260 #endif
2261
2262 void HeapShared::init_for_dumping(TRAPS) {
2263 if (CDSConfig::is_dumping_heap()) {
2264 setup_test_class(ArchiveHeapTestClass);
2265 init_subgraph_entry_fields(CHECK);
2266 }
2267 }
2268
2269 void HeapShared::init_heap_writer() {
2270 if (HeapShared::is_writing_streaming_mode()) {
2271 AOTStreamedHeapWriter::init();
2272 } else {
2273 AOTMappedHeapWriter::init();
2274 }
2275 }
2276
2277 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[]) {
2278 _num_total_subgraph_recordings = 0;
2279 _num_total_walked_objs = 0;
2280 _num_total_archived_objs = 0;
2281 _num_total_recorded_klasses = 0;
2282 _num_total_verifications = 0;
2283
2284 // For each class X that has one or more archived fields:
2285 // [1] Dump the subgraph of each archived field
2286 // [2] Create a list of all the class of the objects that can be reached
2287 // by any of these static fields.
2288 // At runtime, these classes are initialized before X's archived fields
2289 // are restored by HeapShared::initialize_from_archived_subgraph().
2290 for (int i = 0; fields[i].valid(); ) {
2291 ArchivableStaticFieldInfo* info = &fields[i];
2292 const char* klass_name = info->klass_name;
2293 start_recording_subgraph(info->klass, klass_name);
2294
2295 // If you have specified consecutive fields of the same klass in
2296 // fields[], these will be archived in the same
2297 // {start_recording_subgraph ... done_recording_subgraph} pass to
2298 // save time.
2299 for (; fields[i].valid(); i++) {
2300 ArchivableStaticFieldInfo* f = &fields[i];
2301 if (f->klass_name != klass_name) {
2302 break;
2303 }
2304
2305 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2306 f->offset, f->field_name);
2307 }
2308 done_recording_subgraph(info->klass, klass_name);
2309 }
2310
2311 log_info(aot, heap)("Archived subgraph records = %zu",
2312 _num_total_subgraph_recordings);
2313 log_info(aot, heap)(" Walked %zu objects", _num_total_walked_objs);
2314 log_info(aot, heap)(" Archived %zu objects", _num_total_archived_objs);
2315 log_info(aot, heap)(" Recorded %zu klasses", _num_total_recorded_klasses);
2316
2317 #ifndef PRODUCT
2318 for (int i = 0; fields[i].valid(); i++) {
2319 ArchivableStaticFieldInfo* f = &fields[i];
2320 verify_subgraph_from_static_field(f->klass, f->offset);
2321 }
2322 log_info(aot, heap)(" Verified %zu references", _num_total_verifications);
2323 #endif
2324 }
2325
2326 bool HeapShared::is_interned_string(oop obj) {
2327 if (!java_lang_String::is_instance(obj)) {
2328 return false;
2329 }
2330
2331 ResourceMark rm;
2332 int len = 0;
2333 jchar* name = java_lang_String::as_unicode_string_or_null(obj, len);
2334 if (name == nullptr) {
2335 fatal("Insufficient memory for dumping");
2336 }
2337 return StringTable::lookup(name, len) == obj;
2338 }
2339
2340 bool HeapShared::is_dumped_interned_string(oop o) {
2341 return is_interned_string(o) && has_been_archived(o);
2342 }
2343
2344 // These tables should be used only within the CDS safepoint, so
2345 // delete them before we exit the safepoint. Otherwise the table will
2346 // contain bad oops after a GC.
2347 void HeapShared::delete_tables_with_raw_oops() {
2348 assert(_seen_objects_table == nullptr, "should have been deleted");
2349
2350 if (is_writing_mapping_mode()) {
2351 AOTMappedHeapWriter::delete_tables_with_raw_oops();
2352 } else {
2353 assert(is_writing_streaming_mode(), "what other mode?");
2354 AOTStreamedHeapWriter::delete_tables_with_raw_oops();
2355 }
2356 }
2357
2358 void HeapShared::debug_trace() {
2359 ResourceMark rm;
2360 oop referrer = _object_being_archived.referrer();
2361 if (referrer != nullptr) {
2362 LogStream ls(Log(aot, heap)::error());
2363 ls.print_cr("Reference trace");
2364 CDSHeapVerifier::trace_to_root(&ls, referrer);
2365 }
2366 }
2367
2368 #ifndef PRODUCT
2369 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2370 // region. This way we can quickly relocate all the pointers without using
2371 // BasicOopIterateClosure at runtime.
2372 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2373 void* _start;
2374 BitMap *_oopmap;
2375 size_t _num_total_oops;
2376 size_t _num_null_oops;
2377 public:
2378 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2379 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2380
2381 virtual void do_oop(narrowOop* p) {
2382 assert(UseCompressedOops, "sanity");
2383 _num_total_oops ++;
2384 narrowOop v = *p;
2385 if (!CompressedOops::is_null(v)) {
2386 size_t idx = p - (narrowOop*)_start;
2387 _oopmap->set_bit(idx);
2388 } else {
2389 _num_null_oops ++;
2390 }
2391 }
2392 virtual void do_oop(oop* p) {
2393 assert(!UseCompressedOops, "sanity");
2394 _num_total_oops ++;
2395 if ((*p) != nullptr) {
2396 size_t idx = p - (oop*)_start;
2397 _oopmap->set_bit(idx);
2398 } else {
2399 _num_null_oops ++;
2400 }
2401 }
2402 size_t num_total_oops() const { return _num_total_oops; }
2403 size_t num_null_oops() const { return _num_null_oops; }
2404 };
2405 #endif
2406
2407 void HeapShared::count_allocation(size_t size) {
2408 _total_obj_count ++;
2409 _total_obj_size += size;
2410 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2411 if (size <= (size_t(1) << i)) {
2412 _alloc_count[i] ++;
2413 _alloc_size[i] += size;
2414 return;
2415 }
2416 }
2417 }
2418
2419 static double avg_size(size_t size, size_t count) {
2420 double avg = 0;
2421 if (count > 0) {
2422 avg = double(size * HeapWordSize) / double(count);
2423 }
2424 return avg;
2425 }
2426
2427 void HeapShared::print_stats() {
2428 size_t huge_count = _total_obj_count;
2429 size_t huge_size = _total_obj_size;
2430
2431 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2432 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2433 size_t count = _alloc_count[i];
2434 size_t size = _alloc_size[i];
2435 log_info(aot, heap)("%8zu objects are <= %-6zu"
2436 " bytes (total %8zu bytes, avg %8.1f bytes)",
2437 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2438 huge_count -= count;
2439 huge_size -= size;
2440 }
2441
2442 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2443 ", avg %8.1f bytes)",
2444 huge_count, huge_size * HeapWordSize,
2445 avg_size(huge_size, huge_count));
2446 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2447 ", avg %8.1f bytes)",
2448 _total_obj_count, _total_obj_size * HeapWordSize,
2449 avg_size(_total_obj_size, _total_obj_count));
2450 }
2451
2452 bool HeapShared::is_metadata_field(oop src_obj, int offset) {
2453 bool result = false;
2454 do_metadata_offsets(src_obj, [&](int metadata_offset) {
2455 if (metadata_offset == offset) {
2456 result = true;
2457 }
2458 });
2459 return result;
2460 }
2461
2462 void HeapShared::remap_dumped_metadata(oop src_obj, address archived_object) {
2463 do_metadata_offsets(src_obj, [&](int offset) {
2464 Metadata** buffered_field_addr = (Metadata**)(archived_object + offset);
2465 Metadata* native_ptr = *buffered_field_addr;
2466
2467 if (native_ptr == nullptr) {
2468 return;
2469 }
2470
2471 native_ptr = RegeneratedClasses::maybe_get_regenerated_object(native_ptr);
2472
2473 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
2474 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
2475 *buffered_field_addr = (Metadata*)requested_native_ptr;
2476 });
2477 }
2478
2479 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2480 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2481 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2482 if (k == nullptr) {
2483 return false;
2484 } else {
2485 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2486 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2487 fieldDescriptor fd;
2488 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2489 oop m = k->java_mirror();
2490 oop f = m->obj_field(fd.offset());
2491 if (CompressedOops::is_null(f)) {
2492 return false;
2493 }
2494 } else {
2495 return false;
2496 }
2497 }
2498 return true;
2499 }
2500
2501 #endif // INCLUDE_CDS_JAVA_HEAP