53 #include "classfile/javaClasses.hpp"
54 #include "classfile/moduleEntry.hpp"
55 #include "classfile/packageEntry.hpp"
56 #include "classfile/symbolTable.hpp"
57 #include "classfile/systemDictionary.hpp"
58 #include "classfile/systemDictionaryShared.hpp"
59 #include "classfile/vmClasses.hpp"
60 #include "logging/log.hpp"
61 #include "logging/logStream.hpp"
62 #include "memory/allocation.inline.hpp"
63 #include "memory/classLoaderMetaspace.hpp"
64 #include "memory/metadataFactory.hpp"
65 #include "memory/metaspace.hpp"
66 #include "memory/resourceArea.hpp"
67 #include "memory/universe.hpp"
68 #include "oops/access.inline.hpp"
69 #include "oops/klass.inline.hpp"
70 #include "oops/objArrayKlass.hpp"
71 #include "oops/oop.inline.hpp"
72 #include "oops/oopHandle.inline.hpp"
73 #include "oops/weakHandle.inline.hpp"
74 #include "runtime/arguments.hpp"
75 #include "runtime/atomic.hpp"
76 #include "runtime/handles.inline.hpp"
77 #include "runtime/mutex.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "utilities/growableArray.hpp"
80 #include "utilities/macros.hpp"
81 #include "utilities/ostream.hpp"
82
83 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
84
85 void ClassLoaderData::init_null_class_loader_data() {
86 assert(_the_null_class_loader_data == NULL, "cannot initialize twice");
87 assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice");
88
89 _the_null_class_loader_data = new ClassLoaderData(Handle(), false);
90 ClassLoaderDataGraph::_head = _the_null_class_loader_data;
91 assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be");
92
377
378 #ifdef ASSERT
379 oop m = k->java_mirror();
380 assert(m != NULL, "NULL mirror");
381 assert(m->is_a(vmClasses::Class_klass()), "invalid mirror");
382 #endif
383 klass_closure->do_klass(k);
384 }
385 }
386
387 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
388 // Lock-free access requires load_acquire
389 for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
390 if (k->is_instance_klass()) {
391 f(InstanceKlass::cast(k));
392 }
393 assert(k != k->next_link(), "no loops!");
394 }
395 }
396
397 void ClassLoaderData::modules_do(void f(ModuleEntry*)) {
398 assert_locked_or_safepoint(Module_lock);
399 if (_unnamed_module != NULL) {
400 f(_unnamed_module);
401 }
402 if (_modules != NULL) {
403 for (int i = 0; i < _modules->table_size(); i++) {
404 for (ModuleEntry* entry = _modules->bucket(i);
405 entry != NULL;
406 entry = entry->next()) {
407 f(entry);
408 }
409 }
410 }
411 }
412
413 void ClassLoaderData::packages_do(void f(PackageEntry*)) {
414 assert_locked_or_safepoint(Module_lock);
415 if (_packages != NULL) {
416 for (int i = 0; i < _packages->table_size(); i++) {
543 }
544 ShouldNotReachHere(); // should have found this class!!
545 }
546
547 void ClassLoaderData::unload() {
548 _unloading = true;
549
550 LogTarget(Trace, class, loader, data) lt;
551 if (lt.is_enabled()) {
552 ResourceMark rm;
553 LogStream ls(lt);
554 ls.print("unload");
555 print_value_on(&ls);
556 ls.cr();
557 }
558
559 // Some items on the _deallocate_list need to free their C heap structures
560 // if they are not already on the _klasses list.
561 free_deallocate_list_C_heap_structures();
562
563 // Clean up class dependencies and tell serviceability tools
564 // these classes are unloading. Must be called
565 // after erroneous classes are released.
566 classes_do(InstanceKlass::unload_class);
567
568 // Method::clear_jmethod_ids only sets the jmethod_ids to NULL without
569 // releasing the memory for related JNIMethodBlocks and JNIMethodBlockNodes.
570 // This is done intentionally because native code (e.g. JVMTI agent) holding
571 // jmethod_ids may access them after the associated classes and class loader
572 // are unloaded. The Java Native Interface Specification says "method ID
573 // does not prevent the VM from unloading the class from which the ID has
574 // been derived. After the class is unloaded, the method or field ID becomes
575 // invalid". In real world usages, the native code may rely on jmethod_ids
576 // being NULL after class unloading. Hence, it is unsafe to free the memory
577 // from the VM side without knowing when native code is going to stop using
578 // them.
579 if (_jmethod_ids != NULL) {
580 Method::clear_jmethod_ids(this);
581 }
582
846 void ClassLoaderData::free_deallocate_list() {
847 // This must be called at a safepoint because it depends on metadata walking at
848 // safepoint cleanup time.
849 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
850 assert(!is_unloading(), "only called for ClassLoaderData that are not unloading");
851 if (_deallocate_list == NULL) {
852 return;
853 }
854 // Go backwards because this removes entries that are freed.
855 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
856 Metadata* m = _deallocate_list->at(i);
857 if (!m->on_stack()) {
858 _deallocate_list->remove_at(i);
859 // There are only three types of metadata that we deallocate directly.
860 // Cast them so they can be used by the template function.
861 if (m->is_method()) {
862 MetadataFactory::free_metadata(this, (Method*)m);
863 } else if (m->is_constantPool()) {
864 MetadataFactory::free_metadata(this, (ConstantPool*)m);
865 } else if (m->is_klass()) {
866 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
867 } else {
868 ShouldNotReachHere();
869 }
870 } else {
871 // Metadata is alive.
872 // If scratch_class is on stack then it shouldn't be on this list!
873 assert(!m->is_klass() || !((InstanceKlass*)m)->is_scratch_class(),
874 "scratch classes on this list should be dead");
875 // Also should assert that other metadata on the list was found in handles.
876 // Some cleaning remains.
877 ClassLoaderDataGraph::set_should_clean_deallocate_lists();
878 }
879 }
880 }
881
882 // This is distinct from free_deallocate_list. For class loader data that are
883 // unloading, this frees the C heap memory for items on the list, and unlinks
884 // scratch or error classes so that unloading events aren't triggered for these
885 // classes. The metadata is removed with the unloading metaspace.
886 // There isn't C heap memory allocated for methods, so nothing is done for them.
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53 #include "classfile/javaClasses.hpp"
54 #include "classfile/moduleEntry.hpp"
55 #include "classfile/packageEntry.hpp"
56 #include "classfile/symbolTable.hpp"
57 #include "classfile/systemDictionary.hpp"
58 #include "classfile/systemDictionaryShared.hpp"
59 #include "classfile/vmClasses.hpp"
60 #include "logging/log.hpp"
61 #include "logging/logStream.hpp"
62 #include "memory/allocation.inline.hpp"
63 #include "memory/classLoaderMetaspace.hpp"
64 #include "memory/metadataFactory.hpp"
65 #include "memory/metaspace.hpp"
66 #include "memory/resourceArea.hpp"
67 #include "memory/universe.hpp"
68 #include "oops/access.inline.hpp"
69 #include "oops/klass.inline.hpp"
70 #include "oops/objArrayKlass.hpp"
71 #include "oops/oop.inline.hpp"
72 #include "oops/oopHandle.inline.hpp"
73 #include "oops/inlineKlass.inline.hpp"
74 #include "oops/weakHandle.inline.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/atomic.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/mutex.hpp"
79 #include "runtime/safepoint.hpp"
80 #include "utilities/growableArray.hpp"
81 #include "utilities/macros.hpp"
82 #include "utilities/ostream.hpp"
83
84 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
85
86 void ClassLoaderData::init_null_class_loader_data() {
87 assert(_the_null_class_loader_data == NULL, "cannot initialize twice");
88 assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice");
89
90 _the_null_class_loader_data = new ClassLoaderData(Handle(), false);
91 ClassLoaderDataGraph::_head = _the_null_class_loader_data;
92 assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be");
93
378
379 #ifdef ASSERT
380 oop m = k->java_mirror();
381 assert(m != NULL, "NULL mirror");
382 assert(m->is_a(vmClasses::Class_klass()), "invalid mirror");
383 #endif
384 klass_closure->do_klass(k);
385 }
386 }
387
388 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
389 // Lock-free access requires load_acquire
390 for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
391 if (k->is_instance_klass()) {
392 f(InstanceKlass::cast(k));
393 }
394 assert(k != k->next_link(), "no loops!");
395 }
396 }
397
398 void ClassLoaderData::inline_classes_do(void f(InlineKlass*)) {
399 // Lock-free access requires load_acquire
400 for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
401 if (k->is_inline_klass()) {
402 f(InlineKlass::cast(k));
403 }
404 assert(k != k->next_link(), "no loops!");
405 }
406 }
407
408 void ClassLoaderData::modules_do(void f(ModuleEntry*)) {
409 assert_locked_or_safepoint(Module_lock);
410 if (_unnamed_module != NULL) {
411 f(_unnamed_module);
412 }
413 if (_modules != NULL) {
414 for (int i = 0; i < _modules->table_size(); i++) {
415 for (ModuleEntry* entry = _modules->bucket(i);
416 entry != NULL;
417 entry = entry->next()) {
418 f(entry);
419 }
420 }
421 }
422 }
423
424 void ClassLoaderData::packages_do(void f(PackageEntry*)) {
425 assert_locked_or_safepoint(Module_lock);
426 if (_packages != NULL) {
427 for (int i = 0; i < _packages->table_size(); i++) {
554 }
555 ShouldNotReachHere(); // should have found this class!!
556 }
557
558 void ClassLoaderData::unload() {
559 _unloading = true;
560
561 LogTarget(Trace, class, loader, data) lt;
562 if (lt.is_enabled()) {
563 ResourceMark rm;
564 LogStream ls(lt);
565 ls.print("unload");
566 print_value_on(&ls);
567 ls.cr();
568 }
569
570 // Some items on the _deallocate_list need to free their C heap structures
571 // if they are not already on the _klasses list.
572 free_deallocate_list_C_heap_structures();
573
574 inline_classes_do(InlineKlass::cleanup);
575
576 // Clean up class dependencies and tell serviceability tools
577 // these classes are unloading. Must be called
578 // after erroneous classes are released.
579 classes_do(InstanceKlass::unload_class);
580
581 // Method::clear_jmethod_ids only sets the jmethod_ids to NULL without
582 // releasing the memory for related JNIMethodBlocks and JNIMethodBlockNodes.
583 // This is done intentionally because native code (e.g. JVMTI agent) holding
584 // jmethod_ids may access them after the associated classes and class loader
585 // are unloaded. The Java Native Interface Specification says "method ID
586 // does not prevent the VM from unloading the class from which the ID has
587 // been derived. After the class is unloaded, the method or field ID becomes
588 // invalid". In real world usages, the native code may rely on jmethod_ids
589 // being NULL after class unloading. Hence, it is unsafe to free the memory
590 // from the VM side without knowing when native code is going to stop using
591 // them.
592 if (_jmethod_ids != NULL) {
593 Method::clear_jmethod_ids(this);
594 }
595
859 void ClassLoaderData::free_deallocate_list() {
860 // This must be called at a safepoint because it depends on metadata walking at
861 // safepoint cleanup time.
862 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
863 assert(!is_unloading(), "only called for ClassLoaderData that are not unloading");
864 if (_deallocate_list == NULL) {
865 return;
866 }
867 // Go backwards because this removes entries that are freed.
868 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
869 Metadata* m = _deallocate_list->at(i);
870 if (!m->on_stack()) {
871 _deallocate_list->remove_at(i);
872 // There are only three types of metadata that we deallocate directly.
873 // Cast them so they can be used by the template function.
874 if (m->is_method()) {
875 MetadataFactory::free_metadata(this, (Method*)m);
876 } else if (m->is_constantPool()) {
877 MetadataFactory::free_metadata(this, (ConstantPool*)m);
878 } else if (m->is_klass()) {
879 if (!((Klass*)m)->is_inline_klass()) {
880 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
881 } else {
882 MetadataFactory::free_metadata(this, (InlineKlass*)m);
883 }
884 } else {
885 ShouldNotReachHere();
886 }
887 } else {
888 // Metadata is alive.
889 // If scratch_class is on stack then it shouldn't be on this list!
890 assert(!m->is_klass() || !((InstanceKlass*)m)->is_scratch_class(),
891 "scratch classes on this list should be dead");
892 // Also should assert that other metadata on the list was found in handles.
893 // Some cleaning remains.
894 ClassLoaderDataGraph::set_should_clean_deallocate_lists();
895 }
896 }
897 }
898
899 // This is distinct from free_deallocate_list. For class loader data that are
900 // unloading, this frees the C heap memory for items on the list, and unlinks
901 // scratch or error classes so that unloading events aren't triggered for these
902 // classes. The metadata is removed with the unloading metaspace.
903 // There isn't C heap memory allocated for methods, so nothing is done for them.
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