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src/hotspot/share/cds/heapShared.cpp

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   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/aotReferenceObjSupport.hpp"
  30 #include "cds/archiveBuilder.hpp"
  31 #include "cds/archiveHeapLoader.hpp"
  32 #include "cds/archiveHeapWriter.hpp"
  33 #include "cds/archiveUtils.hpp"
  34 #include "cds/cdsConfig.hpp"
  35 #include "cds/cdsEnumKlass.hpp"
  36 #include "cds/cdsHeapVerifier.hpp"
  37 #include "cds/heapShared.hpp"
  38 #include "cds/metaspaceShared.hpp"
  39 #include "classfile/classLoaderData.hpp"
  40 #include "classfile/classLoaderExt.hpp"
  41 #include "classfile/javaClasses.inline.hpp"
  42 #include "classfile/modules.hpp"
  43 #include "classfile/stringTable.hpp"
  44 #include "classfile/symbolTable.hpp"

  72 #include "gc/g1/g1CollectedHeap.hpp"
  73 #endif
  74 
  75 #if INCLUDE_CDS_JAVA_HEAP
  76 
  77 struct ArchivableStaticFieldInfo {
  78   const char* klass_name;
  79   const char* field_name;
  80   InstanceKlass* klass;
  81   int offset;
  82   BasicType type;
  83 
  84   ArchivableStaticFieldInfo(const char* k, const char* f)
  85   : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
  86 
  87   bool valid() {
  88     return klass_name != nullptr;
  89   }
  90 };
  91 











  92 DumpedInternedStrings *HeapShared::_dumped_interned_strings = nullptr;
  93 
  94 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
  95 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
  96 size_t HeapShared::_total_obj_count;
  97 size_t HeapShared::_total_obj_size;
  98 
  99 #ifndef PRODUCT
 100 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
 101 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
 102 static const char* _test_class_name = nullptr;
 103 static Klass* _test_class = nullptr;
 104 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
 105 #endif
 106 
 107 
 108 //
 109 // If you add new entries to the following tables, you should know what you're doing!
 110 //
 111 
 112 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
 113   {"java/lang/Integer$IntegerCache",              "archivedCache"},
 114   {"java/lang/Long$LongCache",                    "archivedCache"},
 115   {"java/lang/Byte$ByteCache",                    "archivedCache"},
 116   {"java/lang/Short$ShortCache",                  "archivedCache"},
 117   {"java/lang/Character$CharacterCache",          "archivedCache"},
 118   {"java/util/jar/Attributes$Name",               "KNOWN_NAMES"},
 119   {"sun/util/locale/BaseLocale",                  "constantBaseLocales"},
 120   {"jdk/internal/module/ArchivedModuleGraph",     "archivedModuleGraph"},
 121   {"java/util/ImmutableCollections",              "archivedObjects"},
 122   {"java/lang/ModuleLayer",                       "EMPTY_LAYER"},
 123   {"java/lang/module/Configuration",              "EMPTY_CONFIGURATION"},
 124   {"jdk/internal/math/FDBigInteger",              "archivedCaches"},

 125 
 126 #ifndef PRODUCT
 127   {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
 128 #endif
 129   {nullptr, nullptr},
 130 };
 131 
 132 // full module graph
 133 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
 134   {"jdk/internal/loader/ArchivedClassLoaders",    "archivedClassLoaders"},
 135   {ARCHIVED_BOOT_LAYER_CLASS,                     ARCHIVED_BOOT_LAYER_FIELD},
 136   {"java/lang/Module$ArchivedData",               "archivedData"},
 137   {nullptr, nullptr},
 138 };
 139 
 140 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
 141 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
 142 GrowableArrayCHeap<oop, mtClassShared>* HeapShared::_pending_roots = nullptr;

 143 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_root_segments = nullptr;
 144 int HeapShared::_root_segment_max_size_elems;
 145 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
 146 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
 147 
 148 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
 149   for (int i = 0; fields[i].valid(); i++) {
 150     if (fields[i].klass == ik) {
 151       return true;
 152     }
 153   }
 154   return false;
 155 }
 156 
 157 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
 158   return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
 159          is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
 160 }
 161 
 162 unsigned HeapShared::oop_hash(oop const& p) {

 210                          CHECK);
 211   Handle boot_loader(THREAD, result.get_oop());
 212   reset_states(boot_loader(), CHECK);
 213 }
 214 
 215 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
 216 
 217 bool HeapShared::has_been_archived(oop obj) {
 218   assert(CDSConfig::is_dumping_heap(), "dump-time only");
 219   return archived_object_cache()->get(obj) != nullptr;
 220 }
 221 
 222 int HeapShared::append_root(oop obj) {
 223   assert(CDSConfig::is_dumping_heap(), "dump-time only");
 224   if (obj != nullptr) {
 225     assert(has_been_archived(obj), "must be");
 226   }
 227   // No GC should happen since we aren't scanning _pending_roots.
 228   assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
 229 
 230   return _pending_roots->append(obj);

 231 }
 232 
 233 objArrayOop HeapShared::root_segment(int segment_idx) {
 234   if (CDSConfig::is_dumping_heap()) {
 235     assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
 236   } else {
 237     assert(CDSConfig::is_using_archive(), "must be");
 238   }
 239 
 240   objArrayOop segment = (objArrayOop)_root_segments->at(segment_idx).resolve();
 241   assert(segment != nullptr, "should have been initialized");
 242   return segment;
 243 }
 244 








































































































































































 245 void HeapShared::get_segment_indexes(int idx, int& seg_idx, int& int_idx) {
 246   assert(_root_segment_max_size_elems > 0, "sanity");
 247 
 248   // Try to avoid divisions for the common case.
 249   if (idx < _root_segment_max_size_elems) {
 250     seg_idx = 0;
 251     int_idx = idx;
 252   } else {
 253     seg_idx = idx / _root_segment_max_size_elems;
 254     int_idx = idx % _root_segment_max_size_elems;
 255   }
 256 
 257   assert(idx == seg_idx * _root_segment_max_size_elems + int_idx,
 258          "sanity: %d index maps to %d segment and %d internal", idx, seg_idx, int_idx);
 259 }
 260 
 261 // Returns an objArray that contains all the roots of the archived objects
 262 oop HeapShared::get_root(int index, bool clear) {
 263   assert(index >= 0, "sanity");
 264   assert(!CDSConfig::is_dumping_heap() && CDSConfig::is_using_archive(), "runtime only");

 389     OopHandle* handle = get(ptr);
 390     if (handle != nullptr) {
 391       handle->release(Universe::vm_global());
 392       remove(ptr);
 393     }
 394   }
 395 };
 396 
 397 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
 398   if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
 399     _scratch_objects_table->set_oop(src, dest);
 400   }
 401 }
 402 
 403 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
 404   return (objArrayOop)_scratch_objects_table->get_oop(src);
 405 }
 406 
 407 void HeapShared::init_dumping() {
 408   _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
 409   _pending_roots = new GrowableArrayCHeap<oop, mtClassShared>(500);
 410 }
 411 
 412 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
 413   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
 414     BasicType bt = (BasicType)i;
 415     if (!is_reference_type(bt)) {
 416       oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
 417       _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);

 418     }
 419   }
 420 }
 421 
 422 // Given java_mirror that represents a (primitive or reference) type T,
 423 // return the "scratch" version that represents the same type T.
 424 // Note that if java_mirror will be returned if it's already a
 425 // scratch mirror.
 426 //
 427 // See java_lang_Class::create_scratch_mirror() for more info.
 428 oop HeapShared::scratch_java_mirror(oop java_mirror) {
 429   assert(java_lang_Class::is_instance(java_mirror), "must be");
 430 
 431   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
 432     BasicType bt = (BasicType)i;
 433     if (!is_reference_type(bt)) {
 434       if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
 435         return java_mirror;
 436       }
 437     }
 438   }
 439 
 440   if (java_lang_Class::is_primitive(java_mirror)) {
 441     return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
 442   } else {
 443     return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
 444   }
 445 }
 446 
 447 oop HeapShared::scratch_java_mirror(BasicType t) {
 448   assert((uint)t < T_VOID+1, "range check");
 449   assert(!is_reference_type(t), "sanity");
 450   return _scratch_basic_type_mirrors[t].resolve();
 451 }
 452 
 453 oop HeapShared::scratch_java_mirror(Klass* k) {
 454   return _scratch_objects_table->get_oop(k);
 455 }
 456 
 457 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {

 458   _scratch_objects_table->set_oop(k, mirror);
 459 }
 460 
 461 void HeapShared::remove_scratch_objects(Klass* k) {
 462   // Klass is being deallocated. Java mirror can still be alive, and it should not
 463   // point to dead klass. We need to break the link from mirror to the Klass.
 464   // See how InstanceKlass::deallocate_contents does it for normal mirrors.
 465   oop mirror = _scratch_objects_table->get_oop(k);
 466   if (mirror != nullptr) {
 467     java_lang_Class::set_klass(mirror, nullptr);
 468   }
 469   _scratch_objects_table->remove_oop(k);
 470   if (k->is_instance_klass()) {
 471     _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
 472   }









 473 }
 474 
 475 //TODO: we eventually want a more direct test for these kinds of things.
 476 //For example the JVM could record some bit of context from the creation
 477 //of the klass, such as who called the hidden class factory.  Using
 478 //string compares on names is fragile and will break as soon as somebody
 479 //changes the names in the JDK code.  See discussion in JDK-8342481 for
 480 //related ideas about marking AOT-related classes.
 481 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
 482   return ik->is_hidden() &&
 483     (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
 484      ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
 485      ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
 486      ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
 487 }
 488 
 489 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
 490   return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
 491 }
 492 

 633   assert(info != nullptr, "must be");
 634   has_oop_pointers = info->has_oop_pointers();
 635   has_native_pointers = info->has_native_pointers();
 636 }
 637 
 638 void HeapShared::set_has_native_pointers(oop src_obj) {
 639   CachedOopInfo* info = archived_object_cache()->get(src_obj);
 640   assert(info != nullptr, "must be");
 641   info->set_has_native_pointers();
 642 }
 643 
 644 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
 645 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
 646 void HeapShared::start_scanning_for_oops() {
 647   {
 648     NoSafepointVerifier nsv;
 649 
 650     // The special subgraph doesn't belong to any class. We use Object_klass() here just
 651     // for convenience.
 652     _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);

 653 
 654     // Cache for recording where the archived objects are copied to
 655     create_archived_object_cache();
 656 
 657     if (UseCompressedOops || UseG1GC) {
 658       aot_log_info(aot)("Heap range = [" PTR_FORMAT " - "  PTR_FORMAT "]",
 659                     UseCompressedOops ? p2i(CompressedOops::begin()) :
 660                                         p2i((address)G1CollectedHeap::heap()->reserved().start()),
 661                     UseCompressedOops ? p2i(CompressedOops::end()) :
 662                                         p2i((address)G1CollectedHeap::heap()->reserved().end()));
 663     }
 664 
 665     archive_subgraphs();
 666   }
 667 
 668   init_seen_objects_table();
 669   Universe::archive_exception_instances();
 670 }
 671 
 672 void HeapShared::end_scanning_for_oops() {
 673   archive_strings();
 674   delete_seen_objects_table();
 675 }
 676 
 677 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
 678   {
 679     NoSafepointVerifier nsv;
 680     CDSHeapVerifier::verify();


 681     check_special_subgraph_classes();
 682   }
 683 
 684   StringTable::write_shared_table();
 685   ArchiveHeapWriter::write(_pending_roots, heap_info);





 686 
 687   ArchiveBuilder::OtherROAllocMark mark;
 688   write_subgraph_info_table();
 689 }
 690 
 691 void HeapShared::scan_java_mirror(oop orig_mirror) {
 692   oop m = scratch_java_mirror(orig_mirror);
 693   if (m != nullptr) { // nullptr if for custom class loader
 694     copy_java_mirror_hashcode(orig_mirror, m);
 695     bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
 696     assert(success, "sanity");
 697   }
 698 }
 699 
 700 void HeapShared::scan_java_class(Klass* orig_k) {
 701   scan_java_mirror(orig_k->java_mirror());
 702 
 703   if (orig_k->is_instance_klass()) {
 704     InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
 705     orig_ik->constants()->prepare_resolved_references_for_archiving();

1071                           which, k->external_name());
1072       FlagSetting fs1(VerifyBeforeGC, true);
1073       FlagSetting fs2(VerifyDuringGC, true);
1074       FlagSetting fs3(VerifyAfterGC,  true);
1075       Universe::heap()->collect(GCCause::_java_lang_system_gc);
1076     }
1077   }
1078 }
1079 
1080 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1081 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1082 //
1083 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1084 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1085 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1086 void HeapShared::resolve_classes(JavaThread* current) {
1087   assert(CDSConfig::is_using_archive(), "runtime only!");
1088   if (!ArchiveHeapLoader::is_in_use()) {
1089     return; // nothing to do
1090   }













1091   resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1092   resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1093 }
1094 
1095 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1096   for (int i = 0; fields[i].valid(); i++) {
1097     ArchivableStaticFieldInfo* info = &fields[i];
1098     TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1099     InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1100     assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1101     resolve_classes_for_subgraph_of(current, k);
1102   }
1103 }
1104 
1105 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1106   JavaThread* THREAD = current;
1107   ExceptionMark em(THREAD);
1108   const ArchivedKlassSubGraphInfoRecord* record =
1109    resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1110   if (HAS_PENDING_EXCEPTION) {

1446 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1447   PointsToOopsChecker points_to_oops_checker;
1448   obj->oop_iterate(&points_to_oops_checker);
1449   return CachedOopInfo(referrer, points_to_oops_checker.result());
1450 }
1451 
1452 void HeapShared::init_box_classes(TRAPS) {
1453   if (ArchiveHeapLoader::is_in_use()) {
1454     vmClasses::Boolean_klass()->initialize(CHECK);
1455     vmClasses::Character_klass()->initialize(CHECK);
1456     vmClasses::Float_klass()->initialize(CHECK);
1457     vmClasses::Double_klass()->initialize(CHECK);
1458     vmClasses::Byte_klass()->initialize(CHECK);
1459     vmClasses::Short_klass()->initialize(CHECK);
1460     vmClasses::Integer_klass()->initialize(CHECK);
1461     vmClasses::Long_klass()->initialize(CHECK);
1462     vmClasses::Void_klass()->initialize(CHECK);
1463   }
1464 }
1465 














1466 // (1) If orig_obj has not been archived yet, archive it.
1467 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1468 //     trace all  objects that are reachable from it, and make sure these objects are archived.
1469 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1470 //     were already archived when this function is called)
1471 bool HeapShared::archive_reachable_objects_from(int level,
1472                                                 KlassSubGraphInfo* subgraph_info,
1473                                                 oop orig_obj) {
1474   assert(orig_obj != nullptr, "must be");
1475   PendingOopStack stack;
1476   stack.push(PendingOop(orig_obj, nullptr, level));
1477 
1478   while (stack.length() > 0) {
1479     PendingOop po = stack.pop();
1480     _object_being_archived = po;
1481     bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1482     _object_being_archived = PendingOop();
1483 
1484     if (!status) {
1485       // Don't archive a subgraph root that's too big. For archives static fields, that's OK

1561 
1562   bool already_archived = has_been_archived(orig_obj);
1563   bool record_klasses_only = already_archived;
1564   if (!already_archived) {
1565     ++_num_new_archived_objs;
1566     if (!archive_object(orig_obj, referrer, subgraph_info)) {
1567       // Skip archiving the sub-graph referenced from the current entry field.
1568       ResourceMark rm;
1569       log_error(aot, heap)(
1570         "Cannot archive the sub-graph referenced from %s object ("
1571         PTR_FORMAT ") size %zu, skipped.",
1572         orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1573       if (level == 1) {
1574         // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1575         // as the Java code will take care of initializing this field dynamically.
1576         return false;
1577       } else {
1578         // We don't know how to handle an object that has been archived, but some of its reachable
1579         // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1580         // we have a real use case.
1581         MetaspaceShared::unrecoverable_writing_error();
1582       }
1583     }
1584   }
1585 
1586   Klass *orig_k = orig_obj->klass();
1587   subgraph_info->add_subgraph_object_klass(orig_k);
1588 
1589   {
1590     // Find all the oops that are referenced by orig_obj, push them onto the stack
1591     // so we can work on them next.
1592     ResourceMark rm;
1593     OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1594     orig_obj->oop_iterate(&pusher);
1595   }
1596 
1597   if (CDSConfig::is_initing_classes_at_dump_time()) {
1598     // The enum klasses are archived with aot-initialized mirror.
1599     // See AOTClassInitializer::can_archive_initialized_mirror().
1600   } else {
1601     if (CDSEnumKlass::is_enum_obj(orig_obj)) {

2015 
2016 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2017                                           bool is_full_module_graph) {
2018   _num_total_subgraph_recordings = 0;
2019   _num_total_walked_objs = 0;
2020   _num_total_archived_objs = 0;
2021   _num_total_recorded_klasses = 0;
2022   _num_total_verifications = 0;
2023 
2024   // For each class X that has one or more archived fields:
2025   // [1] Dump the subgraph of each archived field
2026   // [2] Create a list of all the class of the objects that can be reached
2027   //     by any of these static fields.
2028   //     At runtime, these classes are initialized before X's archived fields
2029   //     are restored by HeapShared::initialize_from_archived_subgraph().
2030   for (int i = 0; fields[i].valid(); ) {
2031     ArchivableStaticFieldInfo* info = &fields[i];
2032     const char* klass_name = info->klass_name;
2033     start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2034 

2035     // If you have specified consecutive fields of the same klass in
2036     // fields[], these will be archived in the same
2037     // {start_recording_subgraph ... done_recording_subgraph} pass to
2038     // save time.
2039     for (; fields[i].valid(); i++) {
2040       ArchivableStaticFieldInfo* f = &fields[i];
2041       if (f->klass_name != klass_name) {
2042         break;
2043       }
2044 

2045       archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2046                                                   f->offset, f->field_name);
2047     }
2048     done_recording_subgraph(info->klass, klass_name);
2049   }
2050 
2051   log_info(aot, heap)("Archived subgraph records = %d",
2052                       _num_total_subgraph_recordings);
2053   log_info(aot, heap)("  Walked %d objects", _num_total_walked_objs);
2054   log_info(aot, heap)("  Archived %d objects", _num_total_archived_objs);
2055   log_info(aot, heap)("  Recorded %d klasses", _num_total_recorded_klasses);
2056 
2057 #ifndef PRODUCT
2058   for (int i = 0; fields[i].valid(); i++) {
2059     ArchivableStaticFieldInfo* f = &fields[i];
2060     verify_subgraph_from_static_field(f->klass, f->offset);
2061   }
2062   log_info(aot, heap)("  Verified %d references", _num_total_verifications);
2063 #endif
2064 }

   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/aotCacheAccess.hpp"
  26 #include "cds/aotArtifactFinder.hpp"
  27 #include "cds/aotClassInitializer.hpp"
  28 #include "cds/aotClassLocation.hpp"
  29 #include "cds/aotLogging.hpp"
  30 #include "cds/aotReferenceObjSupport.hpp"
  31 #include "cds/archiveBuilder.hpp"
  32 #include "cds/archiveHeapLoader.hpp"
  33 #include "cds/archiveHeapWriter.hpp"
  34 #include "cds/archiveUtils.hpp"
  35 #include "cds/cdsConfig.hpp"
  36 #include "cds/cdsEnumKlass.hpp"
  37 #include "cds/cdsHeapVerifier.hpp"
  38 #include "cds/heapShared.hpp"
  39 #include "cds/metaspaceShared.hpp"
  40 #include "classfile/classLoaderData.hpp"
  41 #include "classfile/classLoaderExt.hpp"
  42 #include "classfile/javaClasses.inline.hpp"
  43 #include "classfile/modules.hpp"
  44 #include "classfile/stringTable.hpp"
  45 #include "classfile/symbolTable.hpp"

  73 #include "gc/g1/g1CollectedHeap.hpp"
  74 #endif
  75 
  76 #if INCLUDE_CDS_JAVA_HEAP
  77 
  78 struct ArchivableStaticFieldInfo {
  79   const char* klass_name;
  80   const char* field_name;
  81   InstanceKlass* klass;
  82   int offset;
  83   BasicType type;
  84 
  85   ArchivableStaticFieldInfo(const char* k, const char* f)
  86   : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
  87 
  88   bool valid() {
  89     return klass_name != nullptr;
  90   }
  91 };
  92 
  93 class HeapShared::ContextMark : public StackObj {
  94   ResourceMark rm;
  95 public:
  96   ContextMark(const char* c) : rm{} {
  97     _context->push(c);
  98   }
  99   ~ContextMark() {
 100     _context->pop();
 101   }
 102 };
 103 
 104 DumpedInternedStrings *HeapShared::_dumped_interned_strings = nullptr;
 105 
 106 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
 107 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
 108 size_t HeapShared::_total_obj_count;
 109 size_t HeapShared::_total_obj_size;
 110 
 111 #ifndef PRODUCT
 112 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
 113 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
 114 static const char* _test_class_name = nullptr;
 115 static Klass* _test_class = nullptr;
 116 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
 117 #endif
 118 
 119 
 120 //
 121 // If you add new entries to the following tables, you should know what you're doing!
 122 //
 123 
 124 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
 125   {"java/lang/Integer$IntegerCache",              "archivedCache"},
 126   {"java/lang/Long$LongCache",                    "archivedCache"},
 127   {"java/lang/Byte$ByteCache",                    "archivedCache"},
 128   {"java/lang/Short$ShortCache",                  "archivedCache"},
 129   {"java/lang/Character$CharacterCache",          "archivedCache"},
 130   {"java/util/jar/Attributes$Name",               "KNOWN_NAMES"},
 131   {"sun/util/locale/BaseLocale",                  "constantBaseLocales"},
 132   {"jdk/internal/module/ArchivedModuleGraph",     "archivedModuleGraph"},
 133   {"java/util/ImmutableCollections",              "archivedObjects"},
 134   {"java/lang/ModuleLayer",                       "EMPTY_LAYER"},
 135   {"java/lang/module/Configuration",              "EMPTY_CONFIGURATION"},
 136   {"jdk/internal/math/FDBigInteger",              "archivedCaches"},
 137   {"java/lang/reflect/Proxy$ProxyBuilder",        "archivedData"},    // FIXME -- requires AOTClassLinking
 138 
 139 #ifndef PRODUCT
 140   {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
 141 #endif
 142   {nullptr, nullptr},
 143 };
 144 
 145 // full module graph
 146 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
 147   {"jdk/internal/loader/ArchivedClassLoaders",    "archivedClassLoaders"},
 148   {ARCHIVED_BOOT_LAYER_CLASS,                     ARCHIVED_BOOT_LAYER_FIELD},
 149   {"java/lang/Module$ArchivedData",               "archivedData"},
 150   {nullptr, nullptr},
 151 };
 152 
 153 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
 154 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
 155 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_pending_roots = nullptr;
 156 GrowableArrayCHeap<const char*, mtClassShared>* HeapShared::_context = nullptr;
 157 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_root_segments = nullptr;
 158 int HeapShared::_root_segment_max_size_elems;
 159 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
 160 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
 161 
 162 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
 163   for (int i = 0; fields[i].valid(); i++) {
 164     if (fields[i].klass == ik) {
 165       return true;
 166     }
 167   }
 168   return false;
 169 }
 170 
 171 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
 172   return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
 173          is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
 174 }
 175 
 176 unsigned HeapShared::oop_hash(oop const& p) {

 224                          CHECK);
 225   Handle boot_loader(THREAD, result.get_oop());
 226   reset_states(boot_loader(), CHECK);
 227 }
 228 
 229 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
 230 
 231 bool HeapShared::has_been_archived(oop obj) {
 232   assert(CDSConfig::is_dumping_heap(), "dump-time only");
 233   return archived_object_cache()->get(obj) != nullptr;
 234 }
 235 
 236 int HeapShared::append_root(oop obj) {
 237   assert(CDSConfig::is_dumping_heap(), "dump-time only");
 238   if (obj != nullptr) {
 239     assert(has_been_archived(obj), "must be");
 240   }
 241   // No GC should happen since we aren't scanning _pending_roots.
 242   assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
 243 
 244   OopHandle oh(Universe::vm_global(), obj);
 245   return _pending_roots->append(oh);
 246 }
 247 
 248 objArrayOop HeapShared::root_segment(int segment_idx) {
 249   if (CDSConfig::is_dumping_heap() && !CDSConfig::is_dumping_final_static_archive()) {
 250     assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
 251   } else {
 252     assert(CDSConfig::is_using_archive(), "must be");
 253   }
 254 
 255   objArrayOop segment = (objArrayOop)_root_segments->at(segment_idx).resolve();
 256   assert(segment != nullptr, "should have been initialized");
 257   return segment;
 258 }
 259 
 260 inline unsigned int oop_handle_hash(const OopHandle& oh) {
 261   oop o = oh.resolve();
 262   if (o == nullptr) {
 263     return 0;
 264   } else {
 265     return o->identity_hash();
 266   }
 267 }
 268 
 269 inline bool oop_handle_equals(const OopHandle& a, const OopHandle& b) {
 270   return a.resolve() == b.resolve();
 271 }
 272 
 273 class OrigToScratchObjectTable: public ResourceHashtable<OopHandle, OopHandle,
 274     36137, // prime number
 275     AnyObj::C_HEAP,
 276     mtClassShared,
 277     oop_handle_hash,
 278     oop_handle_equals> {};
 279 
 280 static OrigToScratchObjectTable* _orig_to_scratch_object_table = nullptr;
 281 
 282 void HeapShared::track_scratch_object(oop orig_obj, oop scratch_obj) {
 283   MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
 284   if (_orig_to_scratch_object_table == nullptr) {
 285     _orig_to_scratch_object_table = new (mtClass)OrigToScratchObjectTable();
 286   }
 287 
 288   OopHandle orig_h(Universe::vm_global(), orig_obj);
 289   OopHandle scratch_h(Universe::vm_global(), scratch_obj);
 290   _orig_to_scratch_object_table->put_when_absent(orig_h, scratch_h);
 291 }
 292 
 293 oop HeapShared::orig_to_scratch_object(oop orig_obj) {
 294   MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
 295   if (_orig_to_scratch_object_table != nullptr) {
 296     OopHandle orig(&orig_obj);
 297     OopHandle* v = _orig_to_scratch_object_table->get(orig);
 298     if (v != nullptr) {
 299       return v->resolve();
 300     }
 301   }
 302   return nullptr;
 303 }
 304 
 305 // Permanent oops are used to support AOT-compiled methods, which may have in-line references
 306 // to Strings and MH oops.
 307 //
 308 // At runtime, these oops are stored in _runtime_permanent_oops (which keeps them alive forever)
 309 // and are accssed vis AOTCacheAccess::get_archived_object(int).
 310 struct PermanentOopInfo {
 311   int _index;       // Gets assigned only if HeapShared::get_archived_object_permanent_index() has been called on the object
 312   int _heap_offset; // Offset of the object from the bottom of the archived heap.
 313   PermanentOopInfo(int index, int heap_offset) : _index(index), _heap_offset(heap_offset) {}
 314 };
 315 
 316 class PermanentOopTable: public ResourceHashtable<OopHandle, PermanentOopInfo,
 317     36137, // prime number
 318     AnyObj::C_HEAP,
 319     mtClassShared,
 320     oop_handle_hash,
 321     oop_handle_equals> {};
 322 
 323 static int _dumptime_permanent_oop_count = 0;
 324 static PermanentOopTable* _dumptime_permanent_oop_table = nullptr;
 325 static GrowableArrayCHeap<OopHandle, mtClassShared>* _runtime_permanent_oops = nullptr;
 326 
 327 // ArchiveHeapWriter adds each archived heap object to _dumptime_permanent_oop_table,
 328 // so we can remember their offset (from the bottom of the archived heap).
 329 void HeapShared::add_to_permanent_oop_table(oop obj, int offset) {
 330   assert_at_safepoint();
 331   if (_dumptime_permanent_oop_table == nullptr) {
 332     _dumptime_permanent_oop_table = new (mtClass)PermanentOopTable();
 333   }
 334 
 335   PermanentOopInfo info(-1, offset);
 336   OopHandle oh(Universe::vm_global(), obj);
 337   _dumptime_permanent_oop_table->put_when_absent(oh, info);
 338 }
 339 
 340 // A permanent index is assigned to an archived object ONLY when
 341 // the AOT compiler calls this function.
 342 int HeapShared::get_archived_object_permanent_index(oop obj) {
 343   MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
 344 
 345   if (!CDSConfig::is_dumping_heap()) {
 346     return -1; // Called by the Leyden old workflow
 347   }
 348   if (_dumptime_permanent_oop_table == nullptr) {
 349     return -1;
 350   }
 351 
 352   if (_orig_to_scratch_object_table != nullptr) {
 353     OopHandle orig(&obj);
 354     OopHandle* v = _orig_to_scratch_object_table->get(orig);
 355     if (v != nullptr) {
 356       obj = v->resolve();
 357     }
 358   }
 359 
 360   OopHandle tmp(&obj);
 361   PermanentOopInfo* info = _dumptime_permanent_oop_table->get(tmp);
 362   if (info == nullptr) {
 363     return -1;
 364   } else {
 365     if (info->_index < 0) {
 366       info->_index = _dumptime_permanent_oop_count++;
 367     }
 368     return info->_index;
 369   }
 370 }
 371 
 372 oop HeapShared::get_archived_object(int permanent_index) {
 373   assert(permanent_index >= 0, "sanity");
 374   assert(ArchiveHeapLoader::is_in_use(), "sanity");
 375   assert(_runtime_permanent_oops != nullptr, "sanity");
 376 
 377   return _runtime_permanent_oops->at(permanent_index).resolve();
 378 }
 379 
 380 // Remember all archived heap objects that have a permanent index.
 381 //   table[i] = offset of oop whose permanent index is i.
 382 void CachedCodeDirectoryInternal::dumptime_init_internal() {
 383   const int count = _dumptime_permanent_oop_count;
 384   if (count == 0) {
 385     // Avoid confusing CDS code with zero-sized tables, just return.
 386     log_info(cds)("No permanent oops");
 387     _permanent_oop_count = count;
 388     _permanent_oop_offsets = nullptr;
 389     return;
 390   }
 391 
 392   int* table = (int*)AOTCacheAccess::allocate_aot_code_region(count * sizeof(int));
 393   for (int i = 0; i < count; i++) {
 394     table[count] = -1;
 395   }
 396   _dumptime_permanent_oop_table->iterate([&](OopHandle o, PermanentOopInfo& info) {
 397     int index = info._index;
 398     if (index >= 0) {
 399       assert(index < count, "sanity");
 400       table[index] = info._heap_offset;
 401     }
 402     return true; // continue
 403   });
 404 
 405   for (int i = 0; i < count; i++) {
 406     assert(table[i] >= 0, "must be");
 407   }
 408 
 409   log_info(cds)("Dumped %d permanent oops", count);
 410 
 411   _permanent_oop_count = count;
 412   AOTCacheAccess::set_pointer(&_permanent_oop_offsets, table);
 413 }
 414 
 415 // This is called during the bootstrap of the production run, before any GC can happen.
 416 // Record each permanent oop in a OopHandle for GC safety.
 417 void CachedCodeDirectoryInternal::runtime_init_internal() {
 418   int count = _permanent_oop_count;
 419   int* table = _permanent_oop_offsets;
 420   _runtime_permanent_oops = new GrowableArrayCHeap<OopHandle, mtClassShared>();
 421   for (int i = 0; i < count; i++) {
 422     oop obj = ArchiveHeapLoader::oop_from_offset(table[i]);
 423     OopHandle oh(Universe::vm_global(), obj);
 424     _runtime_permanent_oops->append(oh);
 425   }
 426 };
 427 
 428 void HeapShared::get_segment_indexes(int idx, int& seg_idx, int& int_idx) {
 429   assert(_root_segment_max_size_elems > 0, "sanity");
 430 
 431   // Try to avoid divisions for the common case.
 432   if (idx < _root_segment_max_size_elems) {
 433     seg_idx = 0;
 434     int_idx = idx;
 435   } else {
 436     seg_idx = idx / _root_segment_max_size_elems;
 437     int_idx = idx % _root_segment_max_size_elems;
 438   }
 439 
 440   assert(idx == seg_idx * _root_segment_max_size_elems + int_idx,
 441          "sanity: %d index maps to %d segment and %d internal", idx, seg_idx, int_idx);
 442 }
 443 
 444 // Returns an objArray that contains all the roots of the archived objects
 445 oop HeapShared::get_root(int index, bool clear) {
 446   assert(index >= 0, "sanity");
 447   assert(!CDSConfig::is_dumping_heap() && CDSConfig::is_using_archive(), "runtime only");

 572     OopHandle* handle = get(ptr);
 573     if (handle != nullptr) {
 574       handle->release(Universe::vm_global());
 575       remove(ptr);
 576     }
 577   }
 578 };
 579 
 580 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
 581   if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
 582     _scratch_objects_table->set_oop(src, dest);
 583   }
 584 }
 585 
 586 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
 587   return (objArrayOop)_scratch_objects_table->get_oop(src);
 588 }
 589 
 590 void HeapShared::init_dumping() {
 591   _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
 592   _pending_roots = new GrowableArrayCHeap<OopHandle, mtClassShared>(500);
 593 }
 594 
 595 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
 596   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
 597     BasicType bt = (BasicType)i;
 598     if (!is_reference_type(bt)) {
 599       oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
 600       _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
 601       track_scratch_object(Universe::java_mirror(bt), m);
 602     }
 603   }
 604 }
 605 
 606 // Given java_mirror that represents a (primitive or reference) type T,
 607 // return the "scratch" version that represents the same type T.
 608 // Note that if java_mirror will be returned if it's already a
 609 // scratch mirror.
 610 //
 611 // See java_lang_Class::create_scratch_mirror() for more info.
 612 oop HeapShared::scratch_java_mirror(oop java_mirror) {
 613   assert(java_lang_Class::is_instance(java_mirror), "must be");
 614 
 615   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
 616     BasicType bt = (BasicType)i;
 617     if (!is_reference_type(bt)) {
 618       if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
 619         return java_mirror;
 620       }
 621     }
 622   }
 623 
 624   if (java_lang_Class::is_primitive(java_mirror)) {
 625     return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
 626   } else {
 627     return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
 628   }
 629 }
 630 
 631 oop HeapShared::scratch_java_mirror(BasicType t) {
 632   assert((uint)t < T_VOID+1, "range check");
 633   assert(!is_reference_type(t), "sanity");
 634   return _scratch_basic_type_mirrors[t].resolve();
 635 }
 636 
 637 oop HeapShared::scratch_java_mirror(Klass* k) {
 638   return _scratch_objects_table->get_oop(k);
 639 }
 640 
 641 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
 642   track_scratch_object(k->java_mirror(), mirror);
 643   _scratch_objects_table->set_oop(k, mirror);
 644 }
 645 
 646 void HeapShared::remove_scratch_objects(Klass* k) {
 647   // Klass is being deallocated. Java mirror can still be alive, and it should not
 648   // point to dead klass. We need to break the link from mirror to the Klass.
 649   // See how InstanceKlass::deallocate_contents does it for normal mirrors.
 650   oop mirror = _scratch_objects_table->get_oop(k);
 651   if (mirror != nullptr) {
 652     java_lang_Class::set_klass(mirror, nullptr);
 653   }
 654   _scratch_objects_table->remove_oop(k);
 655   if (k->is_instance_klass()) {
 656     _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
 657   }
 658   if (mirror != nullptr) {
 659     OopHandle tmp(&mirror);
 660     OopHandle* v = _orig_to_scratch_object_table->get(tmp);
 661     if (v != nullptr) {
 662       oop scratch_mirror = v->resolve();
 663       java_lang_Class::set_klass(scratch_mirror, nullptr);
 664       _orig_to_scratch_object_table->remove(tmp);
 665     }
 666   }
 667 }
 668 
 669 //TODO: we eventually want a more direct test for these kinds of things.
 670 //For example the JVM could record some bit of context from the creation
 671 //of the klass, such as who called the hidden class factory.  Using
 672 //string compares on names is fragile and will break as soon as somebody
 673 //changes the names in the JDK code.  See discussion in JDK-8342481 for
 674 //related ideas about marking AOT-related classes.
 675 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
 676   return ik->is_hidden() &&
 677     (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
 678      ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
 679      ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
 680      ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
 681 }
 682 
 683 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
 684   return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
 685 }
 686 

 827   assert(info != nullptr, "must be");
 828   has_oop_pointers = info->has_oop_pointers();
 829   has_native_pointers = info->has_native_pointers();
 830 }
 831 
 832 void HeapShared::set_has_native_pointers(oop src_obj) {
 833   CachedOopInfo* info = archived_object_cache()->get(src_obj);
 834   assert(info != nullptr, "must be");
 835   info->set_has_native_pointers();
 836 }
 837 
 838 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
 839 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
 840 void HeapShared::start_scanning_for_oops() {
 841   {
 842     NoSafepointVerifier nsv;
 843 
 844     // The special subgraph doesn't belong to any class. We use Object_klass() here just
 845     // for convenience.
 846     _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
 847     _context = new GrowableArrayCHeap<const char*, mtClassShared>(250);
 848 
 849     // Cache for recording where the archived objects are copied to
 850     create_archived_object_cache();
 851 
 852     if (UseCompressedOops || UseG1GC) {
 853       aot_log_info(aot)("Heap range = [" PTR_FORMAT " - "  PTR_FORMAT "]",
 854                     UseCompressedOops ? p2i(CompressedOops::begin()) :
 855                                         p2i((address)G1CollectedHeap::heap()->reserved().start()),
 856                     UseCompressedOops ? p2i(CompressedOops::end()) :
 857                                         p2i((address)G1CollectedHeap::heap()->reserved().end()));
 858     }
 859 
 860     archive_subgraphs();
 861   }
 862 
 863   init_seen_objects_table();
 864   Universe::archive_exception_instances();
 865 }
 866 
 867 void HeapShared::end_scanning_for_oops() {
 868   archive_strings();
 869   delete_seen_objects_table();
 870 }
 871 
 872 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
 873   {
 874     NoSafepointVerifier nsv;
 875     if (!SkipArchiveHeapVerification) {
 876       CDSHeapVerifier::verify();
 877     }
 878     check_special_subgraph_classes();
 879   }
 880 
 881   StringTable::write_shared_table();
 882   GrowableArrayCHeap<oop, mtClassShared>* roots = new GrowableArrayCHeap<oop, mtClassShared>(_pending_roots->length());
 883   for (int i = 0; i < _pending_roots->length(); i++) {
 884     roots->append(_pending_roots->at(i).resolve());
 885   }
 886   ArchiveHeapWriter::write(roots, heap_info);
 887   delete roots;
 888 
 889   ArchiveBuilder::OtherROAllocMark mark;
 890   write_subgraph_info_table();
 891 }
 892 
 893 void HeapShared::scan_java_mirror(oop orig_mirror) {
 894   oop m = scratch_java_mirror(orig_mirror);
 895   if (m != nullptr) { // nullptr if for custom class loader
 896     copy_java_mirror_hashcode(orig_mirror, m);
 897     bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
 898     assert(success, "sanity");
 899   }
 900 }
 901 
 902 void HeapShared::scan_java_class(Klass* orig_k) {
 903   scan_java_mirror(orig_k->java_mirror());
 904 
 905   if (orig_k->is_instance_klass()) {
 906     InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
 907     orig_ik->constants()->prepare_resolved_references_for_archiving();

1273                           which, k->external_name());
1274       FlagSetting fs1(VerifyBeforeGC, true);
1275       FlagSetting fs2(VerifyDuringGC, true);
1276       FlagSetting fs3(VerifyAfterGC,  true);
1277       Universe::heap()->collect(GCCause::_java_lang_system_gc);
1278     }
1279   }
1280 }
1281 
1282 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1283 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1284 //
1285 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1286 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1287 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1288 void HeapShared::resolve_classes(JavaThread* current) {
1289   assert(CDSConfig::is_using_archive(), "runtime only!");
1290   if (!ArchiveHeapLoader::is_in_use()) {
1291     return; // nothing to do
1292   }
1293 
1294   if (!CDSConfig::is_using_aot_linked_classes()) {
1295     assert( _run_time_special_subgraph != nullptr, "must be");
1296     Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1297     if (klasses != nullptr) {
1298       for (int i = 0; i < klasses->length(); i++) {
1299         Klass* k = klasses->at(i);
1300         ExceptionMark em(current); // no exception can happen here
1301         resolve_or_init(k, /*do_init*/false, current);
1302       }
1303     }
1304   }
1305 
1306   resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1307   resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1308 }
1309 
1310 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1311   for (int i = 0; fields[i].valid(); i++) {
1312     ArchivableStaticFieldInfo* info = &fields[i];
1313     TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1314     InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1315     assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1316     resolve_classes_for_subgraph_of(current, k);
1317   }
1318 }
1319 
1320 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1321   JavaThread* THREAD = current;
1322   ExceptionMark em(THREAD);
1323   const ArchivedKlassSubGraphInfoRecord* record =
1324    resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1325   if (HAS_PENDING_EXCEPTION) {

1661 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1662   PointsToOopsChecker points_to_oops_checker;
1663   obj->oop_iterate(&points_to_oops_checker);
1664   return CachedOopInfo(referrer, points_to_oops_checker.result());
1665 }
1666 
1667 void HeapShared::init_box_classes(TRAPS) {
1668   if (ArchiveHeapLoader::is_in_use()) {
1669     vmClasses::Boolean_klass()->initialize(CHECK);
1670     vmClasses::Character_klass()->initialize(CHECK);
1671     vmClasses::Float_klass()->initialize(CHECK);
1672     vmClasses::Double_klass()->initialize(CHECK);
1673     vmClasses::Byte_klass()->initialize(CHECK);
1674     vmClasses::Short_klass()->initialize(CHECK);
1675     vmClasses::Integer_klass()->initialize(CHECK);
1676     vmClasses::Long_klass()->initialize(CHECK);
1677     vmClasses::Void_klass()->initialize(CHECK);
1678   }
1679 }
1680 
1681 void HeapShared::exit_on_error() {
1682   if (_context != nullptr) {
1683     ResourceMark rm;
1684     LogStream ls(Log(cds, heap)::error());
1685     ls.print_cr("Context");
1686     for (int i = 0; i < _context->length(); i++) {
1687       const char* s = _context->at(i);
1688       ls.print_cr("- %s", s);
1689     }
1690   }
1691   debug_trace();
1692   MetaspaceShared::unrecoverable_writing_error();
1693 }
1694 
1695 // (1) If orig_obj has not been archived yet, archive it.
1696 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1697 //     trace all  objects that are reachable from it, and make sure these objects are archived.
1698 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1699 //     were already archived when this function is called)
1700 bool HeapShared::archive_reachable_objects_from(int level,
1701                                                 KlassSubGraphInfo* subgraph_info,
1702                                                 oop orig_obj) {
1703   assert(orig_obj != nullptr, "must be");
1704   PendingOopStack stack;
1705   stack.push(PendingOop(orig_obj, nullptr, level));
1706 
1707   while (stack.length() > 0) {
1708     PendingOop po = stack.pop();
1709     _object_being_archived = po;
1710     bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1711     _object_being_archived = PendingOop();
1712 
1713     if (!status) {
1714       // Don't archive a subgraph root that's too big. For archives static fields, that's OK

1790 
1791   bool already_archived = has_been_archived(orig_obj);
1792   bool record_klasses_only = already_archived;
1793   if (!already_archived) {
1794     ++_num_new_archived_objs;
1795     if (!archive_object(orig_obj, referrer, subgraph_info)) {
1796       // Skip archiving the sub-graph referenced from the current entry field.
1797       ResourceMark rm;
1798       log_error(aot, heap)(
1799         "Cannot archive the sub-graph referenced from %s object ("
1800         PTR_FORMAT ") size %zu, skipped.",
1801         orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1802       if (level == 1) {
1803         // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1804         // as the Java code will take care of initializing this field dynamically.
1805         return false;
1806       } else {
1807         // We don't know how to handle an object that has been archived, but some of its reachable
1808         // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1809         // we have a real use case.
1810         exit_on_error();
1811       }
1812     }
1813   }
1814 
1815   Klass *orig_k = orig_obj->klass();
1816   subgraph_info->add_subgraph_object_klass(orig_k);
1817 
1818   {
1819     // Find all the oops that are referenced by orig_obj, push them onto the stack
1820     // so we can work on them next.
1821     ResourceMark rm;
1822     OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1823     orig_obj->oop_iterate(&pusher);
1824   }
1825 
1826   if (CDSConfig::is_initing_classes_at_dump_time()) {
1827     // The enum klasses are archived with aot-initialized mirror.
1828     // See AOTClassInitializer::can_archive_initialized_mirror().
1829   } else {
1830     if (CDSEnumKlass::is_enum_obj(orig_obj)) {

2244 
2245 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2246                                           bool is_full_module_graph) {
2247   _num_total_subgraph_recordings = 0;
2248   _num_total_walked_objs = 0;
2249   _num_total_archived_objs = 0;
2250   _num_total_recorded_klasses = 0;
2251   _num_total_verifications = 0;
2252 
2253   // For each class X that has one or more archived fields:
2254   // [1] Dump the subgraph of each archived field
2255   // [2] Create a list of all the class of the objects that can be reached
2256   //     by any of these static fields.
2257   //     At runtime, these classes are initialized before X's archived fields
2258   //     are restored by HeapShared::initialize_from_archived_subgraph().
2259   for (int i = 0; fields[i].valid(); ) {
2260     ArchivableStaticFieldInfo* info = &fields[i];
2261     const char* klass_name = info->klass_name;
2262     start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2263 
2264     ContextMark cm(klass_name);
2265     // If you have specified consecutive fields of the same klass in
2266     // fields[], these will be archived in the same
2267     // {start_recording_subgraph ... done_recording_subgraph} pass to
2268     // save time.
2269     for (; fields[i].valid(); i++) {
2270       ArchivableStaticFieldInfo* f = &fields[i];
2271       if (f->klass_name != klass_name) {
2272         break;
2273       }
2274 
2275       ContextMark cm(f->field_name);
2276       archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2277                                                   f->offset, f->field_name);
2278     }
2279     done_recording_subgraph(info->klass, klass_name);
2280   }
2281 
2282   log_info(aot, heap)("Archived subgraph records = %d",
2283                       _num_total_subgraph_recordings);
2284   log_info(aot, heap)("  Walked %d objects", _num_total_walked_objs);
2285   log_info(aot, heap)("  Archived %d objects", _num_total_archived_objs);
2286   log_info(aot, heap)("  Recorded %d klasses", _num_total_recorded_klasses);
2287 
2288 #ifndef PRODUCT
2289   for (int i = 0; fields[i].valid(); i++) {
2290     ArchivableStaticFieldInfo* f = &fields[i];
2291     verify_subgraph_from_static_field(f->klass, f->offset);
2292   }
2293   log_info(aot, heap)("  Verified %d references", _num_total_verifications);
2294 #endif
2295 }
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