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 _modules->modules_do(f);
404 }
405 }
406
407 void ClassLoaderData::packages_do(void f(PackageEntry*)) {
408 assert_locked_or_safepoint(Module_lock);
409 if (_packages != NULL) {
410 _packages->packages_do(f);
411 }
412 }
413
414 void ClassLoaderData::record_dependency(const Klass* k) {
415 assert(k != NULL, "invariant");
416
531 }
532 ShouldNotReachHere(); // should have found this class!!
533 }
534
535 void ClassLoaderData::unload() {
536 _unloading = true;
537
538 LogTarget(Trace, class, loader, data) lt;
539 if (lt.is_enabled()) {
540 ResourceMark rm;
541 LogStream ls(lt);
542 ls.print("unload");
543 print_value_on(&ls);
544 ls.cr();
545 }
546
547 // Some items on the _deallocate_list need to free their C heap structures
548 // if they are not already on the _klasses list.
549 free_deallocate_list_C_heap_structures();
550
551 // Clean up class dependencies and tell serviceability tools
552 // these classes are unloading. Must be called
553 // after erroneous classes are released.
554 classes_do(InstanceKlass::unload_class);
555
556 // Method::clear_jmethod_ids only sets the jmethod_ids to NULL without
557 // releasing the memory for related JNIMethodBlocks and JNIMethodBlockNodes.
558 // This is done intentionally because native code (e.g. JVMTI agent) holding
559 // jmethod_ids may access them after the associated classes and class loader
560 // are unloaded. The Java Native Interface Specification says "method ID
561 // does not prevent the VM from unloading the class from which the ID has
562 // been derived. After the class is unloaded, the method or field ID becomes
563 // invalid". In real world usages, the native code may rely on jmethod_ids
564 // being NULL after class unloading. Hence, it is unsafe to free the memory
565 // from the VM side without knowing when native code is going to stop using
566 // them.
567 if (_jmethod_ids != NULL) {
568 Method::clear_jmethod_ids(this);
569 }
570
834 void ClassLoaderData::free_deallocate_list() {
835 // This must be called at a safepoint because it depends on metadata walking at
836 // safepoint cleanup time.
837 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
838 assert(!is_unloading(), "only called for ClassLoaderData that are not unloading");
839 if (_deallocate_list == NULL) {
840 return;
841 }
842 // Go backwards because this removes entries that are freed.
843 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
844 Metadata* m = _deallocate_list->at(i);
845 if (!m->on_stack()) {
846 _deallocate_list->remove_at(i);
847 // There are only three types of metadata that we deallocate directly.
848 // Cast them so they can be used by the template function.
849 if (m->is_method()) {
850 MetadataFactory::free_metadata(this, (Method*)m);
851 } else if (m->is_constantPool()) {
852 MetadataFactory::free_metadata(this, (ConstantPool*)m);
853 } else if (m->is_klass()) {
854 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
855 } else {
856 ShouldNotReachHere();
857 }
858 } else {
859 // Metadata is alive.
860 // If scratch_class is on stack then it shouldn't be on this list!
861 assert(!m->is_klass() || !((InstanceKlass*)m)->is_scratch_class(),
862 "scratch classes on this list should be dead");
863 // Also should assert that other metadata on the list was found in handles.
864 // Some cleaning remains.
865 ClassLoaderDataGraph::set_should_clean_deallocate_lists();
866 }
867 }
868 }
869
870 // This is distinct from free_deallocate_list. For class loader data that are
871 // unloading, this frees the C heap memory for items on the list, and unlinks
872 // scratch or error classes so that unloading events aren't triggered for these
873 // classes. The metadata is removed with the unloading metaspace.
874 // 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 _modules->modules_do(f);
415 }
416 }
417
418 void ClassLoaderData::packages_do(void f(PackageEntry*)) {
419 assert_locked_or_safepoint(Module_lock);
420 if (_packages != NULL) {
421 _packages->packages_do(f);
422 }
423 }
424
425 void ClassLoaderData::record_dependency(const Klass* k) {
426 assert(k != NULL, "invariant");
427
542 }
543 ShouldNotReachHere(); // should have found this class!!
544 }
545
546 void ClassLoaderData::unload() {
547 _unloading = true;
548
549 LogTarget(Trace, class, loader, data) lt;
550 if (lt.is_enabled()) {
551 ResourceMark rm;
552 LogStream ls(lt);
553 ls.print("unload");
554 print_value_on(&ls);
555 ls.cr();
556 }
557
558 // Some items on the _deallocate_list need to free their C heap structures
559 // if they are not already on the _klasses list.
560 free_deallocate_list_C_heap_structures();
561
562 inline_classes_do(InlineKlass::cleanup);
563
564 // Clean up class dependencies and tell serviceability tools
565 // these classes are unloading. Must be called
566 // after erroneous classes are released.
567 classes_do(InstanceKlass::unload_class);
568
569 // Method::clear_jmethod_ids only sets the jmethod_ids to NULL without
570 // releasing the memory for related JNIMethodBlocks and JNIMethodBlockNodes.
571 // This is done intentionally because native code (e.g. JVMTI agent) holding
572 // jmethod_ids may access them after the associated classes and class loader
573 // are unloaded. The Java Native Interface Specification says "method ID
574 // does not prevent the VM from unloading the class from which the ID has
575 // been derived. After the class is unloaded, the method or field ID becomes
576 // invalid". In real world usages, the native code may rely on jmethod_ids
577 // being NULL after class unloading. Hence, it is unsafe to free the memory
578 // from the VM side without knowing when native code is going to stop using
579 // them.
580 if (_jmethod_ids != NULL) {
581 Method::clear_jmethod_ids(this);
582 }
583
847 void ClassLoaderData::free_deallocate_list() {
848 // This must be called at a safepoint because it depends on metadata walking at
849 // safepoint cleanup time.
850 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
851 assert(!is_unloading(), "only called for ClassLoaderData that are not unloading");
852 if (_deallocate_list == NULL) {
853 return;
854 }
855 // Go backwards because this removes entries that are freed.
856 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
857 Metadata* m = _deallocate_list->at(i);
858 if (!m->on_stack()) {
859 _deallocate_list->remove_at(i);
860 // There are only three types of metadata that we deallocate directly.
861 // Cast them so they can be used by the template function.
862 if (m->is_method()) {
863 MetadataFactory::free_metadata(this, (Method*)m);
864 } else if (m->is_constantPool()) {
865 MetadataFactory::free_metadata(this, (ConstantPool*)m);
866 } else if (m->is_klass()) {
867 if (!((Klass*)m)->is_inline_klass()) {
868 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
869 } else {
870 MetadataFactory::free_metadata(this, (InlineKlass*)m);
871 }
872 } else {
873 ShouldNotReachHere();
874 }
875 } else {
876 // Metadata is alive.
877 // If scratch_class is on stack then it shouldn't be on this list!
878 assert(!m->is_klass() || !((InstanceKlass*)m)->is_scratch_class(),
879 "scratch classes on this list should be dead");
880 // Also should assert that other metadata on the list was found in handles.
881 // Some cleaning remains.
882 ClassLoaderDataGraph::set_should_clean_deallocate_lists();
883 }
884 }
885 }
886
887 // This is distinct from free_deallocate_list. For class loader data that are
888 // unloading, this frees the C heap memory for items on the list, and unlinks
889 // scratch or error classes so that unloading events aren't triggered for these
890 // classes. The metadata is removed with the unloading metaspace.
891 // There isn't C heap memory allocated for methods, so nothing is done for them.
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