1 /*
2 * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotArtifactFinder.hpp"
26 #include "cds/aotClassInitializer.hpp"
27 #include "cds/aotClassLocation.hpp"
28 #include "cds/aotLogging.hpp"
29 #include "cds/aotMappedHeapLoader.hpp"
30 #include "cds/aotMappedHeapWriter.hpp"
31 #include "cds/aotMetaspace.hpp"
32 #include "cds/aotOopChecker.hpp"
33 #include "cds/aotReferenceObjSupport.hpp"
34 #include "cds/aotStreamedHeapLoader.hpp"
35 #include "cds/aotStreamedHeapWriter.hpp"
36 #include "cds/archiveBuilder.hpp"
37 #include "cds/archiveUtils.hpp"
38 #include "cds/cds_globals.hpp"
39 #include "cds/cdsConfig.hpp"
40 #include "cds/cdsEnumKlass.hpp"
41 #include "cds/cdsHeapVerifier.hpp"
42 #include "cds/heapShared.inline.hpp"
43 #include "cds/regeneratedClasses.hpp"
44 #include "classfile/classLoaderData.hpp"
45 #include "classfile/javaClasses.inline.hpp"
46 #include "classfile/modules.hpp"
47 #include "classfile/stringTable.hpp"
48 #include "classfile/symbolTable.hpp"
49 #include "classfile/systemDictionary.hpp"
50 #include "classfile/systemDictionaryShared.hpp"
51 #include "classfile/vmClasses.hpp"
52 #include "classfile/vmSymbols.hpp"
53 #include "gc/shared/collectedHeap.hpp"
54 #include "gc/shared/gcLocker.hpp"
55 #include "gc/shared/gcVMOperations.hpp"
56 #include "logging/log.hpp"
57 #include "logging/logStream.hpp"
58 #include "memory/iterator.inline.hpp"
59 #include "memory/resourceArea.hpp"
60 #include "memory/universe.hpp"
61 #include "oops/compressedOops.inline.hpp"
62 #include "oops/fieldStreams.inline.hpp"
63 #include "oops/objArrayOop.inline.hpp"
64 #include "oops/oop.inline.hpp"
65 #include "oops/oopHandle.inline.hpp"
66 #include "oops/typeArrayOop.inline.hpp"
67 #include "prims/jvmtiExport.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/fieldDescriptor.inline.hpp"
70 #include "runtime/globals_extension.hpp"
71 #include "runtime/init.hpp"
72 #include "runtime/javaCalls.hpp"
73 #include "runtime/mutexLocker.hpp"
74 #include "runtime/safepointVerifiers.hpp"
75 #include "utilities/bitMap.inline.hpp"
76 #include "utilities/copy.hpp"
77 #if INCLUDE_G1GC
78 #include "gc/g1/g1CollectedHeap.hpp"
79 #endif
80
81 #if INCLUDE_CDS_JAVA_HEAP
82
83 struct ArchivableStaticFieldInfo {
84 const char* klass_name;
85 const char* field_name;
86 InstanceKlass* klass;
87 int offset;
88 BasicType type;
89
90 ArchivableStaticFieldInfo(const char* k, const char* f)
91 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
92
93 bool valid() {
94 return klass_name != nullptr;
95 }
96 };
97
98 // Anything that goes in the header must be thoroughly purged from uninitialized memory
99 // as it will be written to disk. Therefore, the constructors memset the memory to 0.
100 // This is not the prettiest thing, but we need to know every byte is initialized,
101 // including potential padding between fields.
102
103 ArchiveMappedHeapHeader::ArchiveMappedHeapHeader(size_t ptrmap_start_pos,
104 size_t oopmap_start_pos,
105 HeapRootSegments root_segments) {
106 memset((char*)this, 0, sizeof(*this));
107 _ptrmap_start_pos = ptrmap_start_pos;
108 _oopmap_start_pos = oopmap_start_pos;
109 _root_segments = root_segments;
110 }
111
112 ArchiveMappedHeapHeader::ArchiveMappedHeapHeader() {
113 memset((char*)this, 0, sizeof(*this));
114 }
115
116 ArchiveMappedHeapHeader ArchiveMappedHeapInfo::create_header() {
117 return ArchiveMappedHeapHeader{_ptrmap_start_pos,
118 _oopmap_start_pos,
119 _root_segments};
120 }
121
122 ArchiveStreamedHeapHeader::ArchiveStreamedHeapHeader(size_t forwarding_offset,
123 size_t roots_offset,
124 size_t num_roots,
125 size_t root_highest_object_index_table_offset,
126 size_t num_archived_objects) {
127 memset((char*)this, 0, sizeof(*this));
128 _forwarding_offset = forwarding_offset;
129 _roots_offset = roots_offset;
130 _num_roots = num_roots;
131 _root_highest_object_index_table_offset = root_highest_object_index_table_offset;
132 _num_archived_objects = num_archived_objects;
133 }
134
135 ArchiveStreamedHeapHeader::ArchiveStreamedHeapHeader() {
136 memset((char*)this, 0, sizeof(*this));
137 }
138
139 ArchiveStreamedHeapHeader ArchiveStreamedHeapInfo::create_header() {
140 return ArchiveStreamedHeapHeader{_forwarding_offset,
141 _roots_offset,
142 _num_roots,
143 _root_highest_object_index_table_offset,
144 _num_archived_objects};
145 }
146
147 HeapArchiveMode HeapShared::_heap_load_mode = HeapArchiveMode::_uninitialized;
148 HeapArchiveMode HeapShared::_heap_write_mode = HeapArchiveMode::_uninitialized;
149
150 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
151 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
152 size_t HeapShared::_total_obj_count;
153 size_t HeapShared::_total_obj_size;
154
155 #ifndef PRODUCT
156 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
157 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
158 static const char* _test_class_name = nullptr;
159 static Klass* _test_class = nullptr;
160 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
161 #endif
162
163
164 //
165 // If you add new entries to the following tables, you should know what you're doing!
166 //
167
168 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
169 {"java/lang/Integer$IntegerCache", "archivedCache"},
170 {"java/lang/Long$LongCache", "archivedCache"},
171 {"java/lang/Byte$ByteCache", "archivedCache"},
172 {"java/lang/Short$ShortCache", "archivedCache"},
173 {"java/lang/Character$CharacterCache", "archivedCache"},
174 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
175 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
176 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
177 {"java/util/ImmutableCollections", "archivedObjects"},
178 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
179 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
180 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
181
182 #ifndef PRODUCT
183 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
184 #endif
185 {nullptr, nullptr},
186 };
187
188 // full module graph
189 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
190 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
191 {ARCHIVED_BOOT_LAYER_CLASS, ARCHIVED_BOOT_LAYER_FIELD},
192 {"java/lang/Module$ArchivedData", "archivedData"},
193 {nullptr, nullptr},
194 };
195
196 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
197 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
198 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;
199 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
200 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
201
202 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
203 for (int i = 0; fields[i].valid(); i++) {
204 if (fields[i].klass == ik) {
205 return true;
206 }
207 }
208 return false;
209 }
210
211 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
212 assert(CDSConfig::is_dumping_heap(), "dump-time only");
213 if (!CDSConfig::is_dumping_aot_linked_classes()) {
214 // Legacy CDS archive support (to be deprecated)
215 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
216 is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
217 } else {
218 return false;
219 }
220 }
221
222 oop HeapShared::CachedOopInfo::orig_referrer() const {
223 return _orig_referrer.resolve();
224 }
225
226 unsigned HeapShared::oop_hash(oop const& p) {
227 assert(SafepointSynchronize::is_at_safepoint() ||
228 JavaThread::current()->is_in_no_safepoint_scope(), "sanity");
229 // Do not call p->identity_hash() as that will update the
230 // object header.
231 return primitive_hash(cast_from_oop<intptr_t>(p));
232 }
233
234 unsigned int HeapShared::oop_handle_hash_raw(const OopHandle& oh) {
235 return oop_hash(oh.resolve());
236 }
237
238 unsigned int HeapShared::oop_handle_hash(const OopHandle& oh) {
239 oop o = oh.resolve();
240 if (o == nullptr) {
241 return 0;
242 } else {
243 return o->identity_hash();
244 }
245 }
246
247 bool HeapShared::oop_handle_equals(const OopHandle& a, const OopHandle& b) {
248 return a.resolve() == b.resolve();
249 }
250
251 static void reset_states(oop obj, TRAPS) {
252 Handle h_obj(THREAD, obj);
253 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
254 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
255 Symbol* method_sig = vmSymbols::void_method_signature();
256
257 while (klass != nullptr) {
258 Method* method = klass->find_method(method_name, method_sig);
259 if (method != nullptr) {
260 assert(method->is_private(), "must be");
261 if (log_is_enabled(Debug, aot)) {
262 ResourceMark rm(THREAD);
263 log_debug(aot)(" calling %s", method->name_and_sig_as_C_string());
264 }
265 JavaValue result(T_VOID);
266 JavaCalls::call_special(&result, h_obj, klass,
267 method_name, method_sig, CHECK);
268 }
269 klass = klass->super();
270 }
271 }
272
273 void HeapShared::reset_archived_object_states(TRAPS) {
274 assert(CDSConfig::is_dumping_heap(), "dump-time only");
275 log_debug(aot)("Resetting platform loader");
276 reset_states(SystemDictionary::java_platform_loader(), CHECK);
277 log_debug(aot)("Resetting system loader");
278 reset_states(SystemDictionary::java_system_loader(), CHECK);
279
280 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
281 // directly used for class loading, but rather is used by the core library
282 // to keep track of resources, etc, loaded by the null class loader.
283 //
284 // Note, this object is non-null, and is not the same as
285 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
286 // which is null.
287 log_debug(aot)("Resetting boot loader");
288 JavaValue result(T_OBJECT);
289 JavaCalls::call_static(&result,
290 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
291 vmSymbols::bootLoader_name(),
292 vmSymbols::void_BuiltinClassLoader_signature(),
293 CHECK);
294 Handle boot_loader(THREAD, result.get_oop());
295 reset_states(boot_loader(), CHECK);
296 }
297
298 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
299
300 bool HeapShared::is_archived_heap_in_use() {
301 if (HeapShared::is_loading()) {
302 if (HeapShared::is_loading_streaming_mode()) {
303 return AOTStreamedHeapLoader::is_in_use();
304 } else {
305 return AOTMappedHeapLoader::is_in_use();
306 }
307 }
308
309 return false;
310 }
311
312 bool HeapShared::can_use_archived_heap() {
313 FileMapInfo* static_mapinfo = FileMapInfo::current_info();
314 if (static_mapinfo == nullptr) {
315 return false;
316 }
317 if (!static_mapinfo->has_heap_region()) {
318 return false;
319 }
320 if (!static_mapinfo->object_streaming_mode() &&
321 !Universe::heap()->can_load_archived_objects() &&
322 !UseG1GC) {
323 // Incompatible object format
324 return false;
325 }
326
327 return true;
328 }
329
330 bool HeapShared::is_too_large_to_archive(size_t size) {
331 if (HeapShared::is_writing_streaming_mode()) {
332 return false;
333 } else {
334 return AOTMappedHeapWriter::is_too_large_to_archive(size);
335 }
336 }
337
338 bool HeapShared::is_too_large_to_archive(oop obj) {
339 if (HeapShared::is_writing_streaming_mode()) {
340 return false;
341 } else {
342 return AOTMappedHeapWriter::is_too_large_to_archive(obj);
343 }
344 }
345
346 bool HeapShared::is_string_too_large_to_archive(oop string) {
347 typeArrayOop value = java_lang_String::value_no_keepalive(string);
348 return is_too_large_to_archive(value);
349 }
350
351 void HeapShared::initialize_loading_mode(HeapArchiveMode mode) {
352 assert(_heap_load_mode == HeapArchiveMode::_uninitialized, "already set?");
353 assert(mode != HeapArchiveMode::_uninitialized, "sanity");
354 _heap_load_mode = mode;
355 };
356
357 void HeapShared::initialize_writing_mode() {
358 assert(!FLAG_IS_ERGO(AOTStreamableObjects), "Should not have been ergonomically set yet");
359
360 if (!CDSConfig::is_dumping_archive()) {
361 // We use FLAG_IS_CMDLINE below because we are specifically looking to warn
362 // a user that explicitly sets the flag on the command line for a JVM that is
363 // not dumping an archive.
364 if (FLAG_IS_CMDLINE(AOTStreamableObjects)) {
365 log_warning(cds)("-XX:%cAOTStreamableObjects was specified, "
366 "AOTStreamableObjects is only used for writing "
367 "the AOT cache.",
368 AOTStreamableObjects ? '+' : '-');
369 }
370 }
371
372 // The below checks use !FLAG_IS_DEFAULT instead of FLAG_IS_CMDLINE
373 // because the one step AOT cache creation transfers the AOTStreamableObjects
374 // flag value from the training JVM to the assembly JVM using an environment
375 // variable that sets the flag as ERGO in the assembly JVM.
376 if (FLAG_IS_DEFAULT(AOTStreamableObjects)) {
377 // By default, the value of AOTStreamableObjects should match !UseCompressedOops.
378 FLAG_SET_DEFAULT(AOTStreamableObjects, !UseCompressedOops);
379 } else if (!AOTStreamableObjects && UseZGC) {
380 // Never write mapped heap with ZGC
381 if (CDSConfig::is_dumping_archive()) {
382 log_warning(cds)("Heap archiving without streaming not supported for -XX:+UseZGC");
383 }
384 FLAG_SET_ERGO(AOTStreamableObjects, true);
385 }
386
387 if (CDSConfig::is_dumping_archive()) {
388 // Select default mode
389 assert(_heap_write_mode == HeapArchiveMode::_uninitialized, "already initialized?");
390 _heap_write_mode = AOTStreamableObjects ? HeapArchiveMode::_streaming : HeapArchiveMode::_mapping;
391 }
392 }
393
394 void HeapShared::initialize_streaming() {
395 assert(is_loading_streaming_mode(), "shouldn't call this");
396 if (can_use_archived_heap()) {
397 AOTStreamedHeapLoader::initialize();
398 }
399 }
400
401 void HeapShared::enable_gc() {
402 if (AOTStreamedHeapLoader::is_in_use()) {
403 AOTStreamedHeapLoader::enable_gc();
404 }
405 }
406
407 void HeapShared::materialize_thread_object() {
408 if (AOTStreamedHeapLoader::is_in_use()) {
409 AOTStreamedHeapLoader::materialize_thread_object();
410 }
411 }
412
413 void HeapShared::add_to_dumped_interned_strings(oop string) {
414 assert(HeapShared::is_writing_mapping_mode(), "Only used by this mode");
415 AOTMappedHeapWriter::add_to_dumped_interned_strings(string);
416 }
417
418 void HeapShared::finalize_initialization(FileMapInfo* static_mapinfo) {
419 if (HeapShared::is_loading()) {
420 if (HeapShared::is_loading_streaming_mode()) {
421 // Heap initialization can be done only after vtables are initialized by ReadClosure.
422 AOTStreamedHeapLoader::finish_initialization(static_mapinfo);
423 } else {
424 // Finish up archived heap initialization. These must be
425 // done after ReadClosure.
426 AOTMappedHeapLoader::finish_initialization(static_mapinfo);
427 }
428 }
429 }
430
431 HeapShared::CachedOopInfo* HeapShared::get_cached_oop_info(oop obj) {
432 OopHandle oh(Universe::vm_global(), obj);
433 CachedOopInfo* result = _archived_object_cache->get(oh);
434 oh.release(Universe::vm_global());
435 return result;
436 }
437
438 bool HeapShared::has_been_archived(oop obj) {
439 assert(CDSConfig::is_dumping_heap(), "dump-time only");
440 return get_cached_oop_info(obj) != nullptr;
441 }
442
443 int HeapShared::append_root(oop obj) {
444 assert(CDSConfig::is_dumping_heap(), "dump-time only");
445 if (obj != nullptr) {
446 assert(has_been_archived(obj), "must be");
447 }
448 // No GC should happen since we aren't scanning _pending_roots.
449 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
450
451 return _pending_roots->append(obj);
452 }
453
454 oop HeapShared::get_root(int index, bool clear) {
455 assert(index >= 0, "sanity");
456 assert(!CDSConfig::is_dumping_heap() && CDSConfig::is_using_archive(), "runtime only");
457 assert(is_archived_heap_in_use(), "getting roots into heap that is not used");
458
459 oop result;
460 if (HeapShared::is_loading_streaming_mode()) {
461 result = AOTStreamedHeapLoader::get_root(index);
462 } else {
463 assert(HeapShared::is_loading_mapping_mode(), "must be");
464 result = AOTMappedHeapLoader::get_root(index);
465 }
466
467 if (clear) {
468 clear_root(index);
469 }
470
471 return result;
472 }
473
474 void HeapShared::finish_materialize_objects() {
475 if (AOTStreamedHeapLoader::is_in_use()) {
476 AOTStreamedHeapLoader::finish_materialize_objects();
477 }
478 }
479
480 void HeapShared::clear_root(int index) {
481 assert(index >= 0, "sanity");
482 assert(CDSConfig::is_using_archive(), "must be");
483 if (is_archived_heap_in_use()) {
484 if (log_is_enabled(Debug, aot, heap)) {
485 log_debug(aot, heap)("Clearing root %d: was %zu", index, p2i(get_root(index, false /* clear */)));
486 }
487 if (HeapShared::is_loading_streaming_mode()) {
488 AOTStreamedHeapLoader::clear_root(index);
489 } else {
490 assert(HeapShared::is_loading_mapping_mode(), "must be");
491 AOTMappedHeapLoader::clear_root(index);
492 }
493 }
494 }
495
496 bool HeapShared::archive_object(oop obj, oop referrer, KlassSubGraphInfo* subgraph_info) {
497 assert(CDSConfig::is_dumping_heap(), "dump-time only");
498
499 assert(!obj->is_stackChunk(), "do not archive stack chunks");
500 if (has_been_archived(obj)) {
501 return true;
502 }
503
504 if (is_too_large_to_archive(obj)) {
505 log_debug(aot, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: %zu",
506 p2i(obj), obj->size());
507 debug_trace();
508 return false;
509 }
510
511 AOTOopChecker::check(obj); // Make sure contents of this oop are safe.
512 count_allocation(obj->size());
513
514 if (HeapShared::is_writing_streaming_mode()) {
515 AOTStreamedHeapWriter::add_source_obj(obj);
516 } else {
517 AOTMappedHeapWriter::add_source_obj(obj);
518 }
519
520 OopHandle oh(Universe::vm_global(), obj);
521 CachedOopInfo info = make_cached_oop_info(obj, referrer);
522 archived_object_cache()->put_when_absent(oh, info);
523 archived_object_cache()->maybe_grow();
524
525 Klass* k = obj->klass();
526 if (k->is_instance_klass()) {
527 // Whenever we see a non-array Java object of type X, we mark X to be aot-initialized.
528 // This ensures that during the production run, whenever Java code sees a cached object
529 // of type X, we know that X is already initialized. (see TODO comment below ...)
530
531 if (InstanceKlass::cast(k)->is_enum_subclass()
532 // We can't rerun <clinit> of enum classes (see cdsEnumKlass.cpp) so
533 // we must store them as AOT-initialized.
534 || (subgraph_info == _dump_time_special_subgraph))
535 // TODO: we do this only for the special subgraph for now. Extending this to
536 // other subgraphs would require more refactoring of the core library (such as
537 // move some initialization logic into runtimeSetup()).
538 //
539 // For the other subgraphs, we have a weaker mechanism to ensure that
540 // all classes in a subgraph are initialized before the subgraph is programmatically
541 // returned from jdk.internal.misc.CDS::initializeFromArchive().
542 // See HeapShared::initialize_from_archived_subgraph().
543 {
544 AOTArtifactFinder::add_aot_inited_class(InstanceKlass::cast(k));
545 }
546
547 if (java_lang_Class::is_instance(obj)) {
548 Klass* mirror_k = java_lang_Class::as_Klass(obj);
549 if (mirror_k != nullptr) {
550 AOTArtifactFinder::add_cached_class(mirror_k);
551 }
552 } else if (java_lang_invoke_ResolvedMethodName::is_instance(obj)) {
553 Method* m = java_lang_invoke_ResolvedMethodName::vmtarget(obj);
554 if (m != nullptr) {
555 if (RegeneratedClasses::has_been_regenerated(m)) {
556 m = RegeneratedClasses::get_regenerated_object(m);
557 }
558 InstanceKlass* method_holder = m->method_holder();
559 AOTArtifactFinder::add_cached_class(method_holder);
560 }
561 }
562 }
563
564 if (log_is_enabled(Debug, aot, heap)) {
565 ResourceMark rm;
566 LogTarget(Debug, aot, heap) log;
567 LogStream out(log);
568 out.print("Archived heap object " PTR_FORMAT " : %s ",
569 p2i(obj), obj->klass()->external_name());
570 if (java_lang_Class::is_instance(obj)) {
571 Klass* k = java_lang_Class::as_Klass(obj);
572 if (k != nullptr) {
573 out.print("%s", k->external_name());
574 } else {
575 out.print("primitive");
576 }
577 }
578 out.cr();
579 }
580
581 return true;
582 }
583
584 class MetaspaceObjToOopHandleTable: public HashTable<MetaspaceObj*, OopHandle,
585 36137, // prime number
586 AnyObj::C_HEAP,
587 mtClassShared> {
588 public:
589 oop get_oop(MetaspaceObj* ptr) {
590 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
591 OopHandle* handle = get(ptr);
592 if (handle != nullptr) {
593 return handle->resolve();
594 } else {
595 return nullptr;
596 }
597 }
598 void set_oop(MetaspaceObj* ptr, oop o) {
599 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
600 OopHandle handle(Universe::vm_global(), o);
601 bool is_new = put(ptr, handle);
602 assert(is_new, "cannot set twice");
603 }
604 void remove_oop(MetaspaceObj* ptr) {
605 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
606 OopHandle* handle = get(ptr);
607 if (handle != nullptr) {
608 handle->release(Universe::vm_global());
609 remove(ptr);
610 }
611 }
612 };
613
614 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
615 if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
616 _scratch_objects_table->set_oop(src, dest);
617 }
618 }
619
620 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
621 return (objArrayOop)_scratch_objects_table->get_oop(src);
622 }
623
624 void HeapShared::init_dumping() {
625 _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
626 _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
627 }
628
629 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
630 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
631 BasicType bt = (BasicType)i;
632 if (!is_reference_type(bt)) {
633 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
634 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
635 }
636 }
637 }
638
639 // Given java_mirror that represents a (primitive or reference) type T,
640 // return the "scratch" version that represents the same type T. Note
641 // that java_mirror will be returned if the mirror is already a scratch mirror.
642 //
643 // See java_lang_Class::create_scratch_mirror() for more info.
644 oop HeapShared::scratch_java_mirror(oop java_mirror) {
645 assert(java_lang_Class::is_instance(java_mirror), "must be");
646
647 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
648 BasicType bt = (BasicType)i;
649 if (!is_reference_type(bt)) {
650 if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
651 return java_mirror;
652 }
653 }
654 }
655
656 if (java_lang_Class::is_primitive(java_mirror)) {
657 return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
658 } else {
659 return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
660 }
661 }
662
663 oop HeapShared::scratch_java_mirror(BasicType t) {
664 assert((uint)t < T_VOID+1, "range check");
665 assert(!is_reference_type(t), "sanity");
666 return _scratch_basic_type_mirrors[t].resolve();
667 }
668
669 oop HeapShared::scratch_java_mirror(Klass* k) {
670 return _scratch_objects_table->get_oop(k);
671 }
672
673 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
674 _scratch_objects_table->set_oop(k, mirror);
675 }
676
677 void HeapShared::remove_scratch_objects(Klass* k) {
678 // Klass is being deallocated. Java mirror can still be alive, and it should not
679 // point to dead klass. We need to break the link from mirror to the Klass.
680 // See how InstanceKlass::deallocate_contents does it for normal mirrors.
681 oop mirror = _scratch_objects_table->get_oop(k);
682 if (mirror != nullptr) {
683 java_lang_Class::set_klass(mirror, nullptr);
684 }
685 _scratch_objects_table->remove_oop(k);
686 if (k->is_instance_klass()) {
687 _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
688 }
689 }
690
691 //TODO: we eventually want a more direct test for these kinds of things.
692 //For example the JVM could record some bit of context from the creation
693 //of the klass, such as who called the hidden class factory. Using
694 //string compares on names is fragile and will break as soon as somebody
695 //changes the names in the JDK code. See discussion in JDK-8342481 for
696 //related ideas about marking AOT-related classes.
697 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
698 return ik->is_hidden() &&
699 (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
700 ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
701 ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
702 ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
703 }
704
705 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
706 return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
707 }
708
709 bool HeapShared::is_string_concat_klass(InstanceKlass* ik) {
710 return ik->is_hidden() && ik->name()->starts_with("java/lang/String$$StringConcat");
711 }
712
713 bool HeapShared::is_archivable_hidden_klass(InstanceKlass* ik) {
714 return CDSConfig::is_dumping_method_handles() &&
715 (is_lambda_form_klass(ik) || is_lambda_proxy_klass(ik) || is_string_concat_klass(ik));
716 }
717
718
719 void HeapShared::copy_and_rescan_aot_inited_mirror(InstanceKlass* ik) {
720 ik->set_has_aot_initialized_mirror();
721
722 oop orig_mirror;
723 if (RegeneratedClasses::is_regenerated_object(ik)) {
724 InstanceKlass* orig_ik = RegeneratedClasses::get_original_object(ik);
725 precond(orig_ik->is_initialized());
726 orig_mirror = orig_ik->java_mirror();
727 } else {
728 precond(ik->is_initialized());
729 orig_mirror = ik->java_mirror();
730 }
731
732 oop m = scratch_java_mirror(ik);
733 int nfields = 0;
734 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
735 if (fs.access_flags().is_static()) {
736 fieldDescriptor& fd = fs.field_descriptor();
737 int offset = fd.offset();
738 switch (fd.field_type()) {
739 case T_OBJECT:
740 case T_ARRAY:
741 {
742 oop field_obj = orig_mirror->obj_field(offset);
743 if (offset == java_lang_Class::reflection_data_offset()) {
744 // Class::reflectData use SoftReference, which cannot be archived. Set it
745 // to null and it will be recreated at runtime.
746 field_obj = nullptr;
747 }
748 m->obj_field_put(offset, field_obj);
749 if (field_obj != nullptr) {
750 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
751 assert(success, "sanity");
752 }
753 }
754 break;
755 case T_BOOLEAN:
756 m->bool_field_put(offset, orig_mirror->bool_field(offset));
757 break;
758 case T_BYTE:
759 m->byte_field_put(offset, orig_mirror->byte_field(offset));
760 break;
761 case T_SHORT:
762 m->short_field_put(offset, orig_mirror->short_field(offset));
763 break;
764 case T_CHAR:
765 m->char_field_put(offset, orig_mirror->char_field(offset));
766 break;
767 case T_INT:
768 m->int_field_put(offset, orig_mirror->int_field(offset));
769 break;
770 case T_LONG:
771 m->long_field_put(offset, orig_mirror->long_field(offset));
772 break;
773 case T_FLOAT:
774 m->float_field_put(offset, orig_mirror->float_field(offset));
775 break;
776 case T_DOUBLE:
777 m->double_field_put(offset, orig_mirror->double_field(offset));
778 break;
779 default:
780 ShouldNotReachHere();
781 }
782 nfields ++;
783 }
784 }
785
786 oop class_data = java_lang_Class::class_data(orig_mirror);
787 java_lang_Class::set_class_data(m, class_data);
788 if (class_data != nullptr) {
789 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
790 assert(success, "sanity");
791 }
792
793 if (log_is_enabled(Debug, aot, init)) {
794 ResourceMark rm;
795 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
796 ik->is_hidden() ? " (hidden)" : "",
797 ik->is_enum_subclass() ? " (enum)" : "");
798 }
799 }
800
801 void HeapShared::copy_java_mirror(oop orig_mirror, oop scratch_m) {
802 // We need to retain the identity_hash, because it may have been used by some hashtables
803 // in the shared heap.
804 if (!orig_mirror->fast_no_hash_check()) {
805 intptr_t src_hash = orig_mirror->identity_hash();
806 if (UseCompactObjectHeaders) {
807 narrowKlass nk = CompressedKlassPointers::encode(orig_mirror->klass());
808 scratch_m->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
809 } else {
810 // For valhalla, the prototype header is the same as markWord::prototype();
811 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
812 }
813 assert(scratch_m->mark().is_unlocked(), "sanity");
814
815 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
816 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
817 }
818
819 Klass* k = java_lang_Class::as_Klass(orig_mirror);
820 if (k != nullptr && k->is_instance_klass()) {
821 InstanceKlass* ik = InstanceKlass::cast(k);
822
823 if (ik->is_inline_klass() && ik->is_initialized()) {
824 // Only concrete value classes need the null_reset field
825 InlineKlass* ilk = InlineKlass::cast(k);
826 if (ilk->supports_nullable_layouts()) {
827 scratch_m->obj_field_put(ilk->null_reset_value_offset(), ilk->null_reset_value());
828 }
829 }
830
831 if (ik->has_acmp_maps_offset()) {
832 int maps_offset = ik->acmp_maps_offset();
833 oop maps = orig_mirror->obj_field(maps_offset);
834 scratch_m->obj_field_put(maps_offset, maps);
835 }
836 }
837
838 if (CDSConfig::is_dumping_aot_linked_classes()) {
839 java_lang_Class::set_module(scratch_m, java_lang_Class::module(orig_mirror));
840 java_lang_Class::set_protection_domain(scratch_m, java_lang_Class::protection_domain(orig_mirror));
841 }
842 }
843
844 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
845 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
846 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
847 if (rr != nullptr && !HeapShared::is_too_large_to_archive(rr)) {
848 return HeapShared::scratch_resolved_references(src_ik->constants());
849 }
850 }
851 return nullptr;
852 }
853
854 void HeapShared::archive_strings() {
855 assert(HeapShared::is_writing_mapping_mode(), "should not reach here");
856 oop shared_strings_array = StringTable::init_shared_strings_array();
857 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, shared_strings_array);
858 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
859 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
860 }
861
862 int HeapShared::archive_exception_instance(oop exception) {
863 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
864 assert(success, "sanity");
865 return append_root(exception);
866 }
867
868 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
869 OopHandle oh(&src_obj);
870 CachedOopInfo* info = archived_object_cache()->get(oh);
871 assert(info != nullptr, "must be");
872 has_oop_pointers = info->has_oop_pointers();
873 has_native_pointers = info->has_native_pointers();
874 }
875
876 void HeapShared::set_has_native_pointers(oop src_obj) {
877 OopHandle oh(&src_obj);
878 CachedOopInfo* info = archived_object_cache()->get(oh);
879 assert(info != nullptr, "must be");
880 info->set_has_native_pointers();
881 }
882
883 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
884 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
885 void HeapShared::start_scanning_for_oops() {
886 {
887 NoSafepointVerifier nsv;
888
889 // The special subgraph doesn't belong to any class. We use Object_klass() here just
890 // for convenience.
891 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
892
893 // Cache for recording where the archived objects are copied to
894 create_archived_object_cache();
895
896 if (HeapShared::is_writing_mapping_mode() && (UseG1GC || UseCompressedOops)) {
897 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
898 UseCompressedOops ? p2i(CompressedOops::begin()) :
899 p2i((address)G1CollectedHeap::heap()->reserved().start()),
900 UseCompressedOops ? p2i(CompressedOops::end()) :
901 p2i((address)G1CollectedHeap::heap()->reserved().end()));
902 }
903
904 archive_subgraphs();
905 }
906
907 init_seen_objects_table();
908 Universe::archive_exception_instances();
909 }
910
911 void HeapShared::end_scanning_for_oops() {
912 if (is_writing_mapping_mode()) {
913 archive_strings();
914 }
915 delete_seen_objects_table();
916 }
917
918 void HeapShared::write_heap(ArchiveMappedHeapInfo* mapped_heap_info, ArchiveStreamedHeapInfo* streamed_heap_info) {
919 {
920 NoSafepointVerifier nsv;
921 CDSHeapVerifier::verify();
922 check_special_subgraph_classes();
923 }
924
925 if (HeapShared::is_writing_mapping_mode()) {
926 StringTable::write_shared_table();
927 AOTMappedHeapWriter::write(_pending_roots, mapped_heap_info);
928 } else {
929 assert(HeapShared::is_writing_streaming_mode(), "are there more modes?");
930 AOTStreamedHeapWriter::write(_pending_roots, streamed_heap_info);
931 }
932
933 ArchiveBuilder::OtherROAllocMark mark;
934 write_subgraph_info_table();
935 }
936
937 void HeapShared::scan_java_mirror(oop orig_mirror) {
938 oop m = scratch_java_mirror(orig_mirror);
939 if (m != nullptr) { // nullptr if for custom class loader
940 copy_java_mirror(orig_mirror, m);
941 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
942 assert(success, "sanity");
943 }
944 }
945
946 void HeapShared::scan_java_class(Klass* orig_k) {
947 scan_java_mirror(orig_k->java_mirror());
948
949 if (orig_k->is_instance_klass()) {
950 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
951 orig_ik->constants()->prepare_resolved_references_for_archiving();
952 objArrayOop rr = get_archived_resolved_references(orig_ik);
953 if (rr != nullptr) {
954 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
955 assert(success, "must be");
956 }
957 }
958 }
959
960 void HeapShared::archive_subgraphs() {
961 assert(CDSConfig::is_dumping_heap(), "must be");
962
963 if (!CDSConfig::is_dumping_aot_linked_classes()) {
964 archive_object_subgraphs(archive_subgraph_entry_fields,
965 false /* is_full_module_graph */);
966 if (CDSConfig::is_dumping_full_module_graph()) {
967 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
968 true /* is_full_module_graph */);
969 }
970 }
971
972 if (CDSConfig::is_dumping_full_module_graph()) {
973 Modules::verify_archived_modules();
974 }
975 }
976
977 //
978 // Subgraph archiving support
979 //
980 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
981 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
982
983 // Get the subgraph_info for Klass k. A new subgraph_info is created if
984 // there is no existing one for k. The subgraph_info records the "buffered"
985 // address of the class.
986 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
987 assert(CDSConfig::is_dumping_heap(), "dump time only");
988 bool created;
989 KlassSubGraphInfo* info =
990 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
991 &created);
992 assert(created, "must not initialize twice");
993 return info;
994 }
995
996 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
997 assert(CDSConfig::is_dumping_heap(), "dump time only");
998 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
999 assert(info != nullptr, "must have been initialized");
1000 return info;
1001 }
1002
1003 // Add an entry field to the current KlassSubGraphInfo.
1004 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
1005 assert(CDSConfig::is_dumping_heap(), "dump time only");
1006 if (_subgraph_entry_fields == nullptr) {
1007 _subgraph_entry_fields =
1008 new (mtClass) GrowableArray<int>(10, mtClass);
1009 }
1010 _subgraph_entry_fields->append(static_field_offset);
1011 _subgraph_entry_fields->append(HeapShared::append_root(v));
1012 }
1013
1014 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
1015 // Only objects of boot classes can be included in sub-graph.
1016 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
1017 assert(CDSConfig::is_dumping_heap(), "dump time only");
1018
1019 if (_subgraph_object_klasses == nullptr) {
1020 _subgraph_object_klasses =
1021 new (mtClass) GrowableArray<Klass*>(50, mtClass);
1022 }
1023
1024 if (_k == orig_k) {
1025 // Don't add the Klass containing the sub-graph to it's own klass
1026 // initialization list.
1027 return;
1028 }
1029
1030 if (orig_k->is_instance_klass()) {
1031 #ifdef ASSERT
1032 InstanceKlass* ik = InstanceKlass::cast(orig_k);
1033 if (CDSConfig::is_dumping_method_handles()) {
1034 // -XX:AOTInitTestClass must be used carefully in regression tests to
1035 // include only classes that are safe to aot-initialize.
1036 assert(ik->class_loader() == nullptr ||
1037 HeapShared::is_lambda_proxy_klass(ik) ||
1038 AOTClassInitializer::has_test_class(),
1039 "we can archive only instances of boot classes or lambda proxy classes");
1040 } else {
1041 assert(ik->class_loader() == nullptr, "must be boot class");
1042 }
1043 #endif
1044 // vmClasses::xxx_klass() are not updated, need to check
1045 // the original Klass*
1046 if (orig_k == vmClasses::String_klass() ||
1047 orig_k == vmClasses::Object_klass()) {
1048 // Initialized early during VM initialization. No need to be added
1049 // to the sub-graph object class list.
1050 return;
1051 }
1052 check_allowed_klass(InstanceKlass::cast(orig_k));
1053 } else if (orig_k->is_objArray_klass()) {
1054 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
1055 if (abk->is_instance_klass()) {
1056 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
1057 "must be boot class");
1058 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
1059 }
1060 if (orig_k == Universe::objectArrayKlass()) {
1061 // Initialized early during Universe::genesis. No need to be added
1062 // to the list.
1063 return;
1064 }
1065 } else {
1066 assert(orig_k->is_typeArray_klass(), "must be");
1067 // Primitive type arrays are created early during Universe::genesis.
1068 return;
1069 }
1070
1071 if (log_is_enabled(Debug, aot, heap)) {
1072 if (!_subgraph_object_klasses->contains(orig_k)) {
1073 ResourceMark rm;
1074 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
1075 }
1076 }
1077
1078 _subgraph_object_klasses->append_if_missing(orig_k);
1079 _has_non_early_klasses |= is_non_early_klass(orig_k);
1080 }
1081
1082 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
1083 #ifndef PRODUCT
1084 if (AOTClassInitializer::has_test_class()) {
1085 // The tests can cache arbitrary types of objects.
1086 return;
1087 }
1088 #endif
1089
1090 if (ik->module()->name() == vmSymbols::java_base()) {
1091 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
1092 return;
1093 }
1094
1095 const char* lambda_msg = "";
1096 if (CDSConfig::is_dumping_method_handles()) {
1097 lambda_msg = ", or a lambda proxy class";
1098 if (HeapShared::is_lambda_proxy_klass(ik) &&
1099 (ik->class_loader() == nullptr ||
1100 ik->class_loader() == SystemDictionary::java_platform_loader() ||
1101 ik->class_loader() == SystemDictionary::java_system_loader())) {
1102 return;
1103 }
1104 }
1105
1106 #ifndef PRODUCT
1107 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
1108 // This class is loaded by ArchiveHeapTestClass
1109 return;
1110 }
1111 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
1112 #else
1113 const char* testcls_msg = "";
1114 #endif
1115
1116 ResourceMark rm;
1117 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
1118 ik->external_name(), lambda_msg, testcls_msg);
1119 AOTMetaspace::unrecoverable_writing_error();
1120 }
1121
1122 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
1123 if (k->is_objArray_klass()) {
1124 k = ObjArrayKlass::cast(k)->bottom_klass();
1125 }
1126 if (k->is_instance_klass()) {
1127 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
1128 ResourceMark rm;
1129 log_info(aot, heap)("non-early: %s", k->external_name());
1130 return true;
1131 } else {
1132 return false;
1133 }
1134 } else {
1135 return false;
1136 }
1137 }
1138
1139 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
1140 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
1141 _k = ArchiveBuilder::get_buffered_klass(info->klass());
1142 _entry_field_records = nullptr;
1143 _subgraph_object_klasses = nullptr;
1144 _is_full_module_graph = info->is_full_module_graph();
1145
1146 if (_is_full_module_graph) {
1147 // Consider all classes referenced by the full module graph as early -- we will be
1148 // allocating objects of these classes during JVMTI early phase, so they cannot
1149 // be processed by (non-early) JVMTI ClassFileLoadHook
1150 _has_non_early_klasses = false;
1151 } else {
1152 _has_non_early_klasses = info->has_non_early_klasses();
1153 }
1154
1155 if (_has_non_early_klasses) {
1156 ResourceMark rm;
1157 log_info(aot, heap)(
1158 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
1159 _k->external_name());
1160 }
1161
1162 // populate the entry fields
1163 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
1164 if (entry_fields != nullptr) {
1165 int num_entry_fields = entry_fields->length();
1166 assert(num_entry_fields % 2 == 0, "sanity");
1167 _entry_field_records =
1168 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
1169 for (int i = 0 ; i < num_entry_fields; i++) {
1170 _entry_field_records->at_put(i, entry_fields->at(i));
1171 }
1172 }
1173
1174 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
1175 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
1176 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
1177 if (recorded_klasses != nullptr) {
1178 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
1179 // programmatically loading a subgraph, we only need to explicitly initialize the classes
1180 // that are not aot-inited.
1181 int num_to_copy = 0;
1182 for (int i = 0; i < recorded_klasses->length(); i++) {
1183 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1184 if (!subgraph_k->has_aot_initialized_mirror()) {
1185 num_to_copy ++;
1186 }
1187 }
1188
1189 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
1190 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
1191 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
1192 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1193 if (subgraph_k->has_aot_initialized_mirror()) {
1194 continue;
1195 }
1196 if (log_is_enabled(Info, aot, heap)) {
1197 ResourceMark rm;
1198 const char* owner_name = is_special ? "<special>" : _k->external_name();
1199 if (subgraph_k->is_instance_klass()) {
1200 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
1201 }
1202 log_info(aot, heap)(
1203 "Archived object klass %s (%2d) => %s",
1204 owner_name, n, subgraph_k->external_name());
1205 }
1206 _subgraph_object_klasses->at_put(n, subgraph_k);
1207 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
1208 n++;
1209 }
1210 }
1211
1212 ArchivePtrMarker::mark_pointer(&_k);
1213 ArchivePtrMarker::mark_pointer(&_entry_field_records);
1214 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
1215 }
1216
1217 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
1218 CompactHashtableWriter* _writer;
1219 public:
1220 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
1221
1222 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
1223 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
1224 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
1225 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
1226 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
1227 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
1228 _writer->add(hash, delta);
1229 }
1230 return true; // keep on iterating
1231 }
1232 };
1233
1234 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
1235 ArchivedKlassSubGraphInfoRecord* record =
1236 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
1237 record->init(info);
1238 if (info == _dump_time_special_subgraph) {
1239 _run_time_special_subgraph = record;
1240 }
1241 return record;
1242 }
1243
1244 // Build the records of archived subgraph infos, which include:
1245 // - Entry points to all subgraphs from the containing class mirror. The entry
1246 // points are static fields in the mirror. For each entry point, the field
1247 // offset, and value are recorded in the sub-graph
1248 // info. The value is stored back to the corresponding field at runtime.
1249 // - A list of klasses that need to be loaded/initialized before archived
1250 // java object sub-graph can be accessed at runtime.
1251 void HeapShared::write_subgraph_info_table() {
1252 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1253 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1254 CompactHashtableStats stats;
1255
1256 _run_time_subgraph_info_table.reset();
1257
1258 CompactHashtableWriter writer(d_table->number_of_entries(), &stats);
1259 CopyKlassSubGraphInfoToArchive copy(&writer);
1260 d_table->iterate(©);
1261 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1262
1263 #ifndef PRODUCT
1264 if (ArchiveHeapTestClass != nullptr) {
1265 size_t len = strlen(ArchiveHeapTestClass) + 1;
1266 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1267 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1268 _archived_ArchiveHeapTestClass = array;
1269 }
1270 #endif
1271 if (log_is_enabled(Info, aot, heap)) {
1272 print_stats();
1273 }
1274 }
1275
1276 void HeapShared::serialize_tables(SerializeClosure* soc) {
1277
1278 #ifndef PRODUCT
1279 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1280 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1281 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1282 setup_test_class(_test_class_name);
1283 }
1284 #endif
1285
1286 _run_time_subgraph_info_table.serialize_header(soc);
1287 soc->do_ptr(&_run_time_special_subgraph);
1288 }
1289
1290 static void verify_the_heap(Klass* k, const char* which) {
1291 if (VerifyArchivedFields > 0) {
1292 ResourceMark rm;
1293 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1294 which, k->external_name());
1295
1296 if (VerifyArchivedFields == 1) {
1297 VM_Verify verify_op;
1298 VMThread::execute(&verify_op);
1299 } else if (VerifyArchivedFields == 2 && is_init_completed()) {
1300 // At this time, the oop->klass() of some archived objects in the heap may not
1301 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1302 // have enough information (object size, oop maps, etc) so that a GC can be safely
1303 // performed.
1304 //
1305 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1306 // to check for GC safety.
1307 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1308 which, k->external_name());
1309 FlagSetting fs1(VerifyBeforeGC, true);
1310 FlagSetting fs2(VerifyDuringGC, true);
1311 FlagSetting fs3(VerifyAfterGC, true);
1312 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1313 }
1314 }
1315 }
1316
1317 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1318 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1319 //
1320 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1321 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1322 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1323 void HeapShared::resolve_classes(JavaThread* current) {
1324 assert(CDSConfig::is_using_archive(), "runtime only!");
1325 if (!is_archived_heap_in_use()) {
1326 return; // nothing to do
1327 }
1328 if (!CDSConfig::is_using_aot_linked_classes()) {
1329 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1330 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1331 }
1332 }
1333
1334 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1335 for (int i = 0; fields[i].valid(); i++) {
1336 ArchivableStaticFieldInfo* info = &fields[i];
1337 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1338 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1339 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1340 resolve_classes_for_subgraph_of(current, k);
1341 }
1342 }
1343
1344 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1345 JavaThread* THREAD = current;
1346 ExceptionMark em(THREAD);
1347 const ArchivedKlassSubGraphInfoRecord* record =
1348 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1349 if (HAS_PENDING_EXCEPTION) {
1350 CLEAR_PENDING_EXCEPTION;
1351 }
1352 if (record == nullptr) {
1353 clear_archived_roots_of(k);
1354 }
1355 }
1356
1357 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1358 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1359 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1360 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1361 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1362 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1363 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1364 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1365 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1366 }
1367 }
1368
1369 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1370 // - interned strings
1371 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1372 // - ConstantPool::resolved_references()
1373 // - Universe::<xxx>_exception_instance()
1374 //
1375 // For example, if this enum class is initialized at AOT cache assembly time:
1376 //
1377 // enum Fruit {
1378 // APPLE, ORANGE, BANANA;
1379 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1380 // }
1381 //
1382 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1383 // should be initialized before any Java code can access the Fruit class. Note that
1384 // HashSet itself doesn't necessary need to be an aot-initialized class.
1385 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1386 if (!is_archived_heap_in_use()) {
1387 return;
1388 }
1389
1390 assert( _run_time_special_subgraph != nullptr, "must be");
1391 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1392 if (klasses != nullptr) {
1393 for (int pass = 0; pass < 2; pass ++) {
1394 for (int i = 0; i < klasses->length(); i++) {
1395 Klass* k = klasses->at(i);
1396 if (k->class_loader_data() == nullptr) {
1397 // This class is not yet loaded. We will initialize it in a later phase.
1398 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1399 // but k is part of AOTLinkedClassCategory::BOOT2.
1400 continue;
1401 }
1402 if (k->class_loader() == class_loader()) {
1403 if (pass == 0) {
1404 if (k->is_instance_klass()) {
1405 InstanceKlass::cast(k)->link_class(CHECK);
1406 }
1407 } else {
1408 resolve_or_init(k, /*do_init*/true, CHECK);
1409 }
1410 }
1411 }
1412 }
1413 }
1414 }
1415
1416 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1417 JavaThread* THREAD = current;
1418 if (!is_archived_heap_in_use()) {
1419 return; // nothing to do
1420 }
1421
1422 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1423 !CDSConfig::is_using_optimized_module_handling() &&
1424 // archive was created with --module-path
1425 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1426 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1427 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1428 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1429 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1430 AOTClassLocationConfig::runtime()->num_module_paths());
1431 return;
1432 }
1433
1434 ExceptionMark em(THREAD);
1435 const ArchivedKlassSubGraphInfoRecord* record =
1436 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1437
1438 if (HAS_PENDING_EXCEPTION) {
1439 CLEAR_PENDING_EXCEPTION;
1440 // None of the field value will be set if there was an exception when initializing the classes.
1441 // The java code will not see any of the archived objects in the
1442 // subgraphs referenced from k in this case.
1443 return;
1444 }
1445
1446 if (record != nullptr) {
1447 init_archived_fields_for(k, record);
1448 }
1449 }
1450
1451 const ArchivedKlassSubGraphInfoRecord*
1452 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1453 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1454
1455 if (!k->in_aot_cache()) {
1456 return nullptr;
1457 }
1458 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1459 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1460
1461 #ifndef PRODUCT
1462 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1463 _test_class = k;
1464 _test_class_record = record;
1465 }
1466 #endif
1467
1468 // Initialize from archived data. Currently this is done only
1469 // during VM initialization time. No lock is needed.
1470 if (record == nullptr) {
1471 if (log_is_enabled(Info, aot, heap)) {
1472 ResourceMark rm(THREAD);
1473 log_info(aot, heap)("subgraph %s is not recorded",
1474 k->external_name());
1475 }
1476 return nullptr;
1477 } else {
1478 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1479 if (log_is_enabled(Info, aot, heap)) {
1480 ResourceMark rm(THREAD);
1481 log_info(aot, heap)("subgraph %s cannot be used because full module graph is disabled",
1482 k->external_name());
1483 }
1484 return nullptr;
1485 }
1486
1487 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1488 if (log_is_enabled(Info, aot, heap)) {
1489 ResourceMark rm(THREAD);
1490 log_info(aot, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1491 k->external_name());
1492 }
1493 return nullptr;
1494 }
1495
1496 if (log_is_enabled(Info, aot, heap)) {
1497 ResourceMark rm;
1498 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1499 }
1500
1501 resolve_or_init(k, do_init, CHECK_NULL);
1502
1503 // Load/link/initialize the klasses of the objects in the subgraph.
1504 // nullptr class loader is used.
1505 Array<Klass*>* klasses = record->subgraph_object_klasses();
1506 if (klasses != nullptr) {
1507 for (int i = 0; i < klasses->length(); i++) {
1508 Klass* klass = klasses->at(i);
1509 if (!klass->in_aot_cache()) {
1510 return nullptr;
1511 }
1512 resolve_or_init(klass, do_init, CHECK_NULL);
1513 }
1514 }
1515 }
1516
1517 return record;
1518 }
1519
1520 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1521 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1522 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1523 if (k == nullptr) {
1524 return;
1525 }
1526 assert(k->defined_by_boot_loader(), "sanity");
1527 resolve_or_init(k, false, CHECK);
1528 if (do_init) {
1529 resolve_or_init(k, true, CHECK);
1530 }
1531 }
1532
1533 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1534 if (!do_init) {
1535 if (k->class_loader_data() == nullptr) {
1536 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1537 if (resolved_k->is_array_klass()) {
1538 assert(resolved_k == k || resolved_k == k->super(), "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1539 } else {
1540 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1541 }
1542 }
1543 } else {
1544 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1545 if (k->is_instance_klass()) {
1546 InstanceKlass* ik = InstanceKlass::cast(k);
1547 ik->initialize(CHECK);
1548 } else if (k->is_objArray_klass()) {
1549 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1550 oak->initialize(CHECK);
1551 }
1552 }
1553 }
1554
1555 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1556 verify_the_heap(k, "before");
1557
1558 Array<int>* entry_field_records = record->entry_field_records();
1559 if (entry_field_records != nullptr) {
1560 int efr_len = entry_field_records->length();
1561 assert(efr_len % 2 == 0, "sanity");
1562 for (int i = 0; i < efr_len; i += 2) {
1563 int field_offset = entry_field_records->at(i);
1564 int root_index = entry_field_records->at(i+1);
1565 // Load the subgraph entry fields from the record and store them back to
1566 // the corresponding fields within the mirror.
1567 oop v = get_root(root_index, /*clear=*/true);
1568 oop m = k->java_mirror();
1569 if (k->has_aot_initialized_mirror()) {
1570 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1571 } else {
1572 m->obj_field_put(field_offset, v);
1573 }
1574 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1575 }
1576
1577 // Done. Java code can see the archived sub-graphs referenced from k's
1578 // mirror after this point.
1579 if (log_is_enabled(Info, aot, heap)) {
1580 ResourceMark rm;
1581 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1582 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1583 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1584 }
1585 }
1586
1587 verify_the_heap(k, "after ");
1588 }
1589
1590 void HeapShared::clear_archived_roots_of(Klass* k) {
1591 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1592 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1593 if (record != nullptr) {
1594 Array<int>* entry_field_records = record->entry_field_records();
1595 if (entry_field_records != nullptr) {
1596 int efr_len = entry_field_records->length();
1597 assert(efr_len % 2 == 0, "sanity");
1598 for (int i = 0; i < efr_len; i += 2) {
1599 int root_index = entry_field_records->at(i+1);
1600 clear_root(root_index);
1601 }
1602 }
1603 }
1604 }
1605
1606 // Push all oop fields (or oop array elemenets in case of an objArray) in
1607 // _referencing_obj onto the _stack.
1608 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1609 PendingOopStack* _stack;
1610 GrowableArray<oop> _found_oop_fields;
1611 int _level;
1612 bool _record_klasses_only;
1613 KlassSubGraphInfo* _subgraph_info;
1614 oop _referencing_obj;
1615 bool _is_java_lang_ref;
1616 public:
1617 OopFieldPusher(PendingOopStack* stack,
1618 int level,
1619 bool record_klasses_only,
1620 KlassSubGraphInfo* subgraph_info,
1621 oop orig) :
1622 _stack(stack),
1623 _found_oop_fields(),
1624 _level(level),
1625 _record_klasses_only(record_klasses_only),
1626 _subgraph_info(subgraph_info),
1627 _referencing_obj(orig) {
1628 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1629 }
1630 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1631 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1632
1633 ~OopFieldPusher() {
1634 while (_found_oop_fields.length() > 0) {
1635 // This produces the exact same traversal order as the previous version
1636 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1637 // walking the oop fields in _referencing_obj by ascending field offsets.
1638 oop obj = _found_oop_fields.pop();
1639 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1640 }
1641 }
1642
1643 protected:
1644 template <class T> void do_oop_work(T *p) {
1645 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1646 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1647 if (obj != nullptr) {
1648 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1649 // Do not follow these fields. They will be cleared to null.
1650 return;
1651 }
1652
1653 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1654 ResourceMark rm;
1655 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1656 _referencing_obj->klass()->external_name(), field_offset,
1657 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1658 if (log_is_enabled(Trace, aot, heap)) {
1659 LogTarget(Trace, aot, heap) log;
1660 LogStream out(log);
1661 obj->print_on(&out);
1662 }
1663 }
1664
1665 _found_oop_fields.push(obj);
1666 }
1667 }
1668
1669 public:
1670 oop referencing_obj() { return _referencing_obj; }
1671 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1672 };
1673
1674 // Checks if an oop has any non-null oop fields
1675 class PointsToOopsChecker : public BasicOopIterateClosure {
1676 bool _result;
1677
1678 template <class T> void check(T *p) {
1679 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1680 }
1681
1682 public:
1683 PointsToOopsChecker() : _result(false) {}
1684 void do_oop(narrowOop *p) { check(p); }
1685 void do_oop( oop *p) { check(p); }
1686 bool result() { return _result; }
1687 };
1688
1689 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1690 PointsToOopsChecker points_to_oops_checker;
1691 obj->oop_iterate(&points_to_oops_checker);
1692 return CachedOopInfo(OopHandle(Universe::vm_global(), referrer), points_to_oops_checker.result());
1693 }
1694
1695 void HeapShared::init_box_classes(TRAPS) {
1696 if (is_archived_heap_in_use()) {
1697 vmClasses::Boolean_klass()->initialize(CHECK);
1698 vmClasses::Character_klass()->initialize(CHECK);
1699 vmClasses::Float_klass()->initialize(CHECK);
1700 vmClasses::Double_klass()->initialize(CHECK);
1701 vmClasses::Byte_klass()->initialize(CHECK);
1702 vmClasses::Short_klass()->initialize(CHECK);
1703 vmClasses::Integer_klass()->initialize(CHECK);
1704 vmClasses::Long_klass()->initialize(CHECK);
1705 vmClasses::Void_klass()->initialize(CHECK);
1706 }
1707 }
1708
1709 // (1) If orig_obj has not been archived yet, archive it.
1710 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1711 // trace all objects that are reachable from it, and make sure these objects are archived.
1712 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1713 // were already archived when this function is called)
1714 bool HeapShared::archive_reachable_objects_from(int level,
1715 KlassSubGraphInfo* subgraph_info,
1716 oop orig_obj) {
1717 assert(orig_obj != nullptr, "must be");
1718 PendingOopStack stack;
1719 stack.push(PendingOop(orig_obj, nullptr, level));
1720
1721 while (stack.length() > 0) {
1722 PendingOop po = stack.pop();
1723 _object_being_archived = po;
1724 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1725 _object_being_archived = PendingOop();
1726
1727 if (!status) {
1728 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1729 // as the Java code will take care of initializing this field dynamically.
1730 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1731 return false;
1732 }
1733 }
1734
1735 return true;
1736 }
1737
1738 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1739 oop orig_obj, oop referrer) {
1740 assert(orig_obj != nullptr, "must be");
1741 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1742 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1743 // If you get an error here, you probably made a change in the JDK library that has added
1744 // these objects that are referenced (directly or indirectly) by static fields.
1745 ResourceMark rm;
1746 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1747 debug_trace();
1748 AOTMetaspace::unrecoverable_writing_error();
1749 }
1750
1751 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1752 ResourceMark rm;
1753 LogTarget(Debug, aot, heap) log;
1754 LogStream out(log);
1755 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1756 Klass* k = java_lang_Class::as_Klass(orig_obj);
1757 if (k != nullptr) {
1758 out.print("%s", k->external_name());
1759 } else {
1760 out.print("primitive");
1761 }
1762 out.print_cr("; scratch mirror = " PTR_FORMAT,
1763 p2i(scratch_java_mirror(orig_obj)));
1764 }
1765
1766 if (java_lang_Class::is_instance(orig_obj)) {
1767 Klass* k = java_lang_Class::as_Klass(orig_obj);
1768 if (RegeneratedClasses::has_been_regenerated(k)) {
1769 orig_obj = RegeneratedClasses::get_regenerated_object(k)->java_mirror();
1770 }
1771 }
1772
1773 if (CDSConfig::is_dumping_aot_linked_classes()) {
1774 if (java_lang_Class::is_instance(orig_obj)) {
1775 orig_obj = scratch_java_mirror(orig_obj);
1776 assert(orig_obj != nullptr, "must be archived");
1777 }
1778 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1779 // Without CDSConfig::is_dumping_aot_linked_classes(), we only allow archived objects to
1780 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1781 // very early by HeapShared::init_box_classes().
1782 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1783 || java_lang_Class::is_primitive(orig_obj)
1784 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1785 || orig_obj == vmClasses::Character_klass()->java_mirror()
1786 || orig_obj == vmClasses::Float_klass()->java_mirror()
1787 || orig_obj == vmClasses::Double_klass()->java_mirror()
1788 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1789 || orig_obj == vmClasses::Short_klass()->java_mirror()
1790 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1791 || orig_obj == vmClasses::Long_klass()->java_mirror()
1792 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1793 orig_obj = scratch_java_mirror(orig_obj);
1794 assert(orig_obj != nullptr, "must be archived");
1795 } else {
1796 // If you get an error here, you probably made a change in the JDK library that has added a Class
1797 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1798 // defined at the top of this file.
1799 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1800 debug_trace();
1801 AOTMetaspace::unrecoverable_writing_error();
1802 }
1803 }
1804
1805 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1806 // orig_obj has already been archived and traced. Nothing more to do.
1807 return true;
1808 } else {
1809 set_has_been_seen_during_subgraph_recording(orig_obj);
1810 }
1811
1812 bool already_archived = has_been_archived(orig_obj);
1813 bool record_klasses_only = already_archived;
1814 if (!already_archived) {
1815 ++_num_new_archived_objs;
1816 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1817 // Skip archiving the sub-graph referenced from the current entry field.
1818 ResourceMark rm;
1819 log_error(aot, heap)(
1820 "Cannot archive the sub-graph referenced from %s object ("
1821 PTR_FORMAT ") size %zu, skipped.",
1822 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1823 if (level == 1) {
1824 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1825 // as the Java code will take care of initializing this field dynamically.
1826 return false;
1827 } else {
1828 // We don't know how to handle an object that has been archived, but some of its reachable
1829 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1830 // we have a real use case.
1831 AOTMetaspace::unrecoverable_writing_error();
1832 }
1833 }
1834 }
1835
1836 Klass *orig_k = orig_obj->klass();
1837 subgraph_info->add_subgraph_object_klass(orig_k);
1838
1839 {
1840 // Find all the oops that are referenced by orig_obj, push them onto the stack
1841 // so we can work on them next.
1842 ResourceMark rm;
1843 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1844 orig_obj->oop_iterate(&pusher);
1845 }
1846
1847 if (CDSConfig::is_dumping_aot_linked_classes()) {
1848 // The enum klasses are archived with aot-initialized mirror.
1849 // See AOTClassInitializer::can_archive_initialized_mirror().
1850 } else {
1851 // This is legacy support for enum classes before JEP 483 -- we cannot rerun
1852 // the enum's <clinit> in the production run, so special handling is needed.
1853 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1854 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1855 }
1856 }
1857
1858 return true;
1859 }
1860
1861 //
1862 // Start from the given static field in a java mirror and archive the
1863 // complete sub-graph of java heap objects that are reached directly
1864 // or indirectly from the starting object by following references.
1865 // Sub-graph archiving restrictions (current):
1866 //
1867 // - All classes of objects in the archived sub-graph (including the
1868 // entry class) must be boot class only.
1869 // - No java.lang.Class instance (java mirror) can be included inside
1870 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1871 //
1872 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1873 //
1874 // 1) Java object sub-graph archiving starts from a given static field
1875 // within a Class instance (java mirror). If the static field is a
1876 // reference field and points to a non-null java object, proceed to
1877 // the next step.
1878 //
1879 // 2) Archives the referenced java object. If an archived copy of the
1880 // current object already exists, updates the pointer in the archived
1881 // copy of the referencing object to point to the current archived object.
1882 // Otherwise, proceed to the next step.
1883 //
1884 // 3) Follows all references within the current java object and recursively
1885 // archive the sub-graph of objects starting from each reference.
1886 //
1887 // 4) Updates the pointer in the archived copy of referencing object to
1888 // point to the current archived object.
1889 //
1890 // 5) The Klass of the current java object is added to the list of Klasses
1891 // for loading and initializing before any object in the archived graph can
1892 // be accessed at runtime.
1893 //
1894 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1895 const char* klass_name,
1896 int field_offset,
1897 const char* field_name) {
1898 assert(CDSConfig::is_dumping_heap(), "dump time only");
1899 assert(k->defined_by_boot_loader(), "must be boot class");
1900
1901 oop m = k->java_mirror();
1902
1903 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1904 oop f = m->obj_field(field_offset);
1905
1906 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1907
1908 if (!CompressedOops::is_null(f)) {
1909 if (log_is_enabled(Trace, aot, heap)) {
1910 LogTarget(Trace, aot, heap) log;
1911 LogStream out(log);
1912 f->print_on(&out);
1913 }
1914
1915 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1916 if (!success) {
1917 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1918 klass_name, field_name);
1919 } else {
1920 // Note: the field value is not preserved in the archived mirror.
1921 // Record the field as a new subGraph entry point. The recorded
1922 // information is restored from the archive at runtime.
1923 subgraph_info->add_subgraph_entry_field(field_offset, f);
1924 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1925 }
1926 } else {
1927 // The field contains null, we still need to record the entry point,
1928 // so it can be restored at runtime.
1929 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1930 }
1931 }
1932
1933 #ifndef PRODUCT
1934 class VerifySharedOopClosure: public BasicOopIterateClosure {
1935 public:
1936 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1937 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1938
1939 protected:
1940 template <class T> void do_oop_work(T *p) {
1941 oop obj = HeapAccess<>::oop_load(p);
1942 if (obj != nullptr) {
1943 HeapShared::verify_reachable_objects_from(obj);
1944 }
1945 }
1946 };
1947
1948 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1949 assert(CDSConfig::is_dumping_heap(), "dump time only");
1950 assert(k->defined_by_boot_loader(), "must be boot class");
1951
1952 oop m = k->java_mirror();
1953 oop f = m->obj_field(field_offset);
1954 if (!CompressedOops::is_null(f)) {
1955 verify_subgraph_from(f);
1956 }
1957 }
1958
1959 void HeapShared::verify_subgraph_from(oop orig_obj) {
1960 if (!has_been_archived(orig_obj)) {
1961 // It's OK for the root of a subgraph to be not archived. See comments in
1962 // archive_reachable_objects_from().
1963 return;
1964 }
1965
1966 // Verify that all objects reachable from orig_obj are archived.
1967 init_seen_objects_table();
1968 verify_reachable_objects_from(orig_obj);
1969 delete_seen_objects_table();
1970 }
1971
1972 void HeapShared::verify_reachable_objects_from(oop obj) {
1973 _num_total_verifications ++;
1974 if (java_lang_Class::is_instance(obj)) {
1975 obj = scratch_java_mirror(obj);
1976 assert(obj != nullptr, "must be");
1977 }
1978 if (!has_been_seen_during_subgraph_recording(obj)) {
1979 set_has_been_seen_during_subgraph_recording(obj);
1980 assert(has_been_archived(obj), "must be");
1981 VerifySharedOopClosure walker;
1982 obj->oop_iterate(&walker);
1983 }
1984 }
1985 #endif
1986
1987 void HeapShared::check_special_subgraph_classes() {
1988 if (CDSConfig::is_dumping_aot_linked_classes()) {
1989 // We can have aot-initialized classes (such as Enums) that can reference objects
1990 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
1991 // aot-initialize classes that are "safe".
1992 //
1993 // TODO: we need an automatic tool that checks the safety of aot-initialized
1994 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
1995 return;
1996 } else {
1997 // In this case, the special subgraph should contain a few specific types
1998 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
1999 int num = klasses->length();
2000 for (int i = 0; i < num; i++) {
2001 Klass* subgraph_k = klasses->at(i);
2002 Symbol* name = subgraph_k->name();
2003
2004 if (subgraph_k->is_identity_class() &&
2005 name != vmSymbols::java_lang_Class() &&
2006 name != vmSymbols::java_lang_String() &&
2007 name != vmSymbols::java_lang_ArithmeticException() &&
2008 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
2009 name != vmSymbols::java_lang_ArrayStoreException() &&
2010 name != vmSymbols::java_lang_ClassCastException() &&
2011 name != vmSymbols::java_lang_InternalError() &&
2012 name != vmSymbols::java_lang_NullPointerException() &&
2013 name != vmSymbols::jdk_internal_vm_PreemptedException()) {
2014 ResourceMark rm;
2015 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
2016 }
2017 }
2018 }
2019 }
2020
2021 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
2022 HeapShared::PendingOop HeapShared::_object_being_archived;
2023 size_t HeapShared::_num_new_walked_objs;
2024 size_t HeapShared::_num_new_archived_objs;
2025 size_t HeapShared::_num_old_recorded_klasses;
2026
2027 size_t HeapShared::_num_total_subgraph_recordings = 0;
2028 size_t HeapShared::_num_total_walked_objs = 0;
2029 size_t HeapShared::_num_total_archived_objs = 0;
2030 size_t HeapShared::_num_total_recorded_klasses = 0;
2031 size_t HeapShared::_num_total_verifications = 0;
2032
2033 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
2034 return _seen_objects_table->get(obj) != nullptr;
2035 }
2036
2037 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
2038 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
2039 _seen_objects_table->put_when_absent(obj, true);
2040 _seen_objects_table->maybe_grow();
2041 ++ _num_new_walked_objs;
2042 }
2043
2044 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
2045 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
2046 init_subgraph_info(k, is_full_module_graph);
2047 init_seen_objects_table();
2048 _num_new_walked_objs = 0;
2049 _num_new_archived_objs = 0;
2050 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
2051 }
2052
2053 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
2054 size_t num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
2055 _num_old_recorded_klasses;
2056 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
2057 "walked %zu objs, archived %zu new objs, recorded %zu classes",
2058 class_name, _num_new_walked_objs, _num_new_archived_objs,
2059 num_new_recorded_klasses);
2060
2061 delete_seen_objects_table();
2062
2063 _num_total_subgraph_recordings ++;
2064 _num_total_walked_objs += _num_new_walked_objs;
2065 _num_total_archived_objs += _num_new_archived_objs;
2066 _num_total_recorded_klasses += num_new_recorded_klasses;
2067 }
2068
2069 class ArchivableStaticFieldFinder: public FieldClosure {
2070 InstanceKlass* _ik;
2071 Symbol* _field_name;
2072 bool _found;
2073 int _offset;
2074 public:
2075 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
2076 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
2077
2078 virtual void do_field(fieldDescriptor* fd) {
2079 if (fd->name() == _field_name) {
2080 assert(!_found, "fields can never be overloaded");
2081 if (is_reference_type(fd->field_type())) {
2082 _found = true;
2083 _offset = fd->offset();
2084 }
2085 }
2086 }
2087 bool found() { return _found; }
2088 int offset() { return _offset; }
2089 };
2090
2091 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
2092 TRAPS) {
2093 for (int i = 0; fields[i].valid(); i++) {
2094 ArchivableStaticFieldInfo* info = &fields[i];
2095 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
2096 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
2097 ResourceMark rm; // for stringStream::as_string() etc.
2098
2099 #ifndef PRODUCT
2100 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
2101 const char* test_class_name = ArchiveHeapTestClass;
2102 #else
2103 bool is_test_class = false;
2104 const char* test_class_name = ""; // avoid C++ printf checks warnings.
2105 #endif
2106
2107 if (is_test_class) {
2108 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
2109 }
2110
2111 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
2112 if (HAS_PENDING_EXCEPTION) {
2113 CLEAR_PENDING_EXCEPTION;
2114 stringStream st;
2115 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
2116 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2117 }
2118
2119 if (!k->is_instance_klass()) {
2120 stringStream st;
2121 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
2122 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2123 }
2124
2125 InstanceKlass* ik = InstanceKlass::cast(k);
2126 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
2127 "Only support boot classes");
2128
2129 if (is_test_class) {
2130 if (ik->module()->is_named()) {
2131 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
2132 // core-lib classes. You need to at least append to the bootclasspath.
2133 stringStream st;
2134 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
2135 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2136 }
2137
2138 if (ik->package() != nullptr) {
2139 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
2140 stringStream st;
2141 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
2142 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2143 }
2144 } else {
2145 if (ik->module()->name() != vmSymbols::java_base()) {
2146 // We don't want to deal with cases when a module is unavailable at runtime.
2147 // FUTURE -- load from archived heap only when module graph has not changed
2148 // between dump and runtime.
2149 stringStream st;
2150 st.print("%s is not in java.base module", info->klass_name);
2151 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2152 }
2153 }
2154
2155 if (is_test_class) {
2156 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
2157 }
2158 ik->initialize(CHECK);
2159
2160 ArchivableStaticFieldFinder finder(ik, field_name);
2161 ik->do_local_static_fields(&finder);
2162 if (!finder.found()) {
2163 stringStream st;
2164 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
2165 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2166 }
2167
2168 info->klass = ik;
2169 info->offset = finder.offset();
2170 }
2171 }
2172
2173 void HeapShared::init_subgraph_entry_fields(TRAPS) {
2174 assert(CDSConfig::is_dumping_heap(), "must be");
2175 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
2176 if (!CDSConfig::is_dumping_aot_linked_classes()) {
2177 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
2178 if (CDSConfig::is_dumping_full_module_graph()) {
2179 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
2180 }
2181 }
2182 }
2183
2184 #ifndef PRODUCT
2185 void HeapShared::setup_test_class(const char* test_class_name) {
2186 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
2187 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
2188 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
2189 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
2190
2191 if (test_class_name != nullptr) {
2192 p[num_slots - 2].klass_name = test_class_name;
2193 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
2194 }
2195 }
2196
2197 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
2198 // during runtime. This may be called before the module system is initialized so
2199 // we cannot rely on InstanceKlass::module(), etc.
2200 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
2201 if (_test_class != nullptr) {
2202 if (ik == _test_class) {
2203 return true;
2204 }
2205 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
2206 if (klasses == nullptr) {
2207 return false;
2208 }
2209
2210 for (int i = 0; i < klasses->length(); i++) {
2211 Klass* k = klasses->at(i);
2212 if (k == ik) {
2213 Symbol* name;
2214 if (k->is_instance_klass()) {
2215 name = InstanceKlass::cast(k)->name();
2216 } else if (k->is_objArray_klass()) {
2217 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
2218 if (!bk->is_instance_klass()) {
2219 return false;
2220 }
2221 name = bk->name();
2222 } else {
2223 return false;
2224 }
2225
2226 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
2227 // to be:
2228 // (A) java.base classes (which must not be in the unnamed module)
2229 // (B) test classes which must be in the unnamed package of the unnamed module.
2230 // So if we see a '/' character in the class name, it must be in (A);
2231 // otherwise it must be in (B).
2232 if (name->index_of_at(0, "/", 1) >= 0) {
2233 return false; // (A)
2234 }
2235
2236 return true; // (B)
2237 }
2238 }
2239 }
2240
2241 return false;
2242 }
2243
2244 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2245 Klass* k = _test_class;
2246 if (k != nullptr && is_archived_heap_in_use()) {
2247 JavaThread* THREAD = current;
2248 ExceptionMark em(THREAD);
2249 const ArchivedKlassSubGraphInfoRecord* record =
2250 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2251
2252 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2253 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2254 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2255 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2256 if (record != nullptr) {
2257 init_archived_fields_for(k, record);
2258 }
2259 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2260 }
2261 }
2262 #endif
2263
2264 void HeapShared::init_for_dumping(TRAPS) {
2265 if (CDSConfig::is_dumping_heap()) {
2266 setup_test_class(ArchiveHeapTestClass);
2267 init_subgraph_entry_fields(CHECK);
2268 }
2269 }
2270
2271 void HeapShared::init_heap_writer() {
2272 if (HeapShared::is_writing_streaming_mode()) {
2273 AOTStreamedHeapWriter::init();
2274 } else {
2275 AOTMappedHeapWriter::init();
2276 }
2277 }
2278
2279 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2280 bool is_full_module_graph) {
2281 _num_total_subgraph_recordings = 0;
2282 _num_total_walked_objs = 0;
2283 _num_total_archived_objs = 0;
2284 _num_total_recorded_klasses = 0;
2285 _num_total_verifications = 0;
2286
2287 // For each class X that has one or more archived fields:
2288 // [1] Dump the subgraph of each archived field
2289 // [2] Create a list of all the class of the objects that can be reached
2290 // by any of these static fields.
2291 // At runtime, these classes are initialized before X's archived fields
2292 // are restored by HeapShared::initialize_from_archived_subgraph().
2293 for (int i = 0; fields[i].valid(); ) {
2294 ArchivableStaticFieldInfo* info = &fields[i];
2295 const char* klass_name = info->klass_name;
2296
2297 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2298
2299 // If you have specified consecutive fields of the same klass in
2300 // fields[], these will be archived in the same
2301 // {start_recording_subgraph ... done_recording_subgraph} pass to
2302 // save time.
2303 for (; fields[i].valid(); i++) {
2304 ArchivableStaticFieldInfo* f = &fields[i];
2305 if (f->klass_name != klass_name) {
2306 break;
2307 }
2308
2309 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2310 f->offset, f->field_name);
2311 }
2312 done_recording_subgraph(info->klass, klass_name);
2313 }
2314
2315 log_info(aot, heap)("Archived subgraph records = %zu",
2316 _num_total_subgraph_recordings);
2317 log_info(aot, heap)(" Walked %zu objects", _num_total_walked_objs);
2318 log_info(aot, heap)(" Archived %zu objects", _num_total_archived_objs);
2319 log_info(aot, heap)(" Recorded %zu klasses", _num_total_recorded_klasses);
2320
2321 #ifndef PRODUCT
2322 for (int i = 0; fields[i].valid(); i++) {
2323 ArchivableStaticFieldInfo* f = &fields[i];
2324 verify_subgraph_from_static_field(f->klass, f->offset);
2325 }
2326 log_info(aot, heap)(" Verified %zu references", _num_total_verifications);
2327 #endif
2328 }
2329
2330 bool HeapShared::is_dumped_interned_string(oop o) {
2331 if (is_writing_mapping_mode()) {
2332 return AOTMappedHeapWriter::is_dumped_interned_string(o);
2333 } else {
2334 return AOTStreamedHeapWriter::is_dumped_interned_string(o);
2335 }
2336 }
2337
2338 // These tables should be used only within the CDS safepoint, so
2339 // delete them before we exit the safepoint. Otherwise the table will
2340 // contain bad oops after a GC.
2341 void HeapShared::delete_tables_with_raw_oops() {
2342 assert(_seen_objects_table == nullptr, "should have been deleted");
2343
2344 if (is_writing_mapping_mode()) {
2345 AOTMappedHeapWriter::delete_tables_with_raw_oops();
2346 } else {
2347 assert(is_writing_streaming_mode(), "what other mode?");
2348 AOTStreamedHeapWriter::delete_tables_with_raw_oops();
2349 }
2350 }
2351
2352 void HeapShared::debug_trace() {
2353 ResourceMark rm;
2354 oop referrer = _object_being_archived.referrer();
2355 if (referrer != nullptr) {
2356 LogStream ls(Log(aot, heap)::error());
2357 ls.print_cr("Reference trace");
2358 CDSHeapVerifier::trace_to_root(&ls, referrer);
2359 }
2360 }
2361
2362 #ifndef PRODUCT
2363 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2364 // region. This way we can quickly relocate all the pointers without using
2365 // BasicOopIterateClosure at runtime.
2366 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2367 void* _start;
2368 BitMap *_oopmap;
2369 size_t _num_total_oops;
2370 size_t _num_null_oops;
2371 public:
2372 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2373 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2374
2375 virtual void do_oop(narrowOop* p) {
2376 assert(UseCompressedOops, "sanity");
2377 _num_total_oops ++;
2378 narrowOop v = *p;
2379 if (!CompressedOops::is_null(v)) {
2380 size_t idx = p - (narrowOop*)_start;
2381 _oopmap->set_bit(idx);
2382 } else {
2383 _num_null_oops ++;
2384 }
2385 }
2386 virtual void do_oop(oop* p) {
2387 assert(!UseCompressedOops, "sanity");
2388 _num_total_oops ++;
2389 if ((*p) != nullptr) {
2390 size_t idx = p - (oop*)_start;
2391 _oopmap->set_bit(idx);
2392 } else {
2393 _num_null_oops ++;
2394 }
2395 }
2396 size_t num_total_oops() const { return _num_total_oops; }
2397 size_t num_null_oops() const { return _num_null_oops; }
2398 };
2399 #endif
2400
2401 void HeapShared::count_allocation(size_t size) {
2402 _total_obj_count ++;
2403 _total_obj_size += size;
2404 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2405 if (size <= (size_t(1) << i)) {
2406 _alloc_count[i] ++;
2407 _alloc_size[i] += size;
2408 return;
2409 }
2410 }
2411 }
2412
2413 static double avg_size(size_t size, size_t count) {
2414 double avg = 0;
2415 if (count > 0) {
2416 avg = double(size * HeapWordSize) / double(count);
2417 }
2418 return avg;
2419 }
2420
2421 void HeapShared::print_stats() {
2422 size_t huge_count = _total_obj_count;
2423 size_t huge_size = _total_obj_size;
2424
2425 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2426 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2427 size_t count = _alloc_count[i];
2428 size_t size = _alloc_size[i];
2429 log_info(aot, heap)("%8zu objects are <= %-6zu"
2430 " bytes (total %8zu bytes, avg %8.1f bytes)",
2431 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2432 huge_count -= count;
2433 huge_size -= size;
2434 }
2435
2436 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2437 ", avg %8.1f bytes)",
2438 huge_count, huge_size * HeapWordSize,
2439 avg_size(huge_size, huge_count));
2440 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2441 ", avg %8.1f bytes)",
2442 _total_obj_count, _total_obj_size * HeapWordSize,
2443 avg_size(_total_obj_size, _total_obj_count));
2444 }
2445
2446 bool HeapShared::is_metadata_field(oop src_obj, int offset) {
2447 bool result = false;
2448 do_metadata_offsets(src_obj, [&](int metadata_offset) {
2449 if (metadata_offset == offset) {
2450 result = true;
2451 }
2452 });
2453 return result;
2454 }
2455
2456 void HeapShared::remap_dumped_metadata(oop src_obj, address archived_object) {
2457 do_metadata_offsets(src_obj, [&](int offset) {
2458 Metadata** buffered_field_addr = (Metadata**)(archived_object + offset);
2459 Metadata* native_ptr = *buffered_field_addr;
2460
2461 if (native_ptr == nullptr) {
2462 return;
2463 }
2464
2465 if (RegeneratedClasses::has_been_regenerated(native_ptr)) {
2466 native_ptr = RegeneratedClasses::get_regenerated_object(native_ptr);
2467 }
2468
2469 address buffered_native_ptr = ArchiveBuilder::current()->get_buffered_addr((address)native_ptr);
2470 address requested_native_ptr = ArchiveBuilder::current()->to_requested(buffered_native_ptr);
2471 *buffered_field_addr = (Metadata*)requested_native_ptr;
2472 });
2473 }
2474
2475 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2476 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2477 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2478 if (k == nullptr) {
2479 return false;
2480 } else {
2481 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2482 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2483 fieldDescriptor fd;
2484 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2485 oop m = k->java_mirror();
2486 oop f = m->obj_field(fd.offset());
2487 if (CompressedOops::is_null(f)) {
2488 return false;
2489 }
2490 } else {
2491 return false;
2492 }
2493 }
2494 return true;
2495 }
2496
2497 #endif // INCLUDE_CDS_JAVA_HEAP