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8197844: JVMTI GetLoadedClasses should use the Access API

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Make sure the holder of a class loader is accessed during iteration of CLDG

Reviewed-by: eosterlund, rkennke
This commit is contained in:
Coleen Phillimore 2018-03-21 17:09:34 -04:00
parent c944c3aba7
commit b15a3ff611
3 changed files with 34 additions and 19 deletions
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33
src/hotspot/share/classfile/classLoaderData.cpp
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@ -610,6 +610,21 @@ Dictionary* ClassLoaderData::create_dictionary() {
return new Dictionary(this, size, resizable);
}
// Tell the GC to keep this klass alive while iterating ClassLoaderDataGraph
oop ClassLoaderData::holder_phantom() {
// A klass that was previously considered dead can be looked up in the
// CLD/SD, and its _java_mirror or _class_loader can be stored in a root
// or a reachable object making it alive again. The SATB part of G1 needs
// to get notified about this potential resurrection, otherwise the marking
// might not find the object.
if (!keep_alive()) {
oop* o = is_anonymous() ? _klasses->java_mirror_handle().ptr_raw() : &_class_loader;
return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(o);
} else {
return NULL;
}
}
// Unloading support
oop ClassLoaderData::keep_alive_object() const {
assert_locked_or_safepoint(_metaspace_lock);
@ -1048,26 +1063,34 @@ void ClassLoaderDataGraph::always_strong_cld_do(CLDClosure* cl) {
}
void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->classes_do(klass_closure);
}
}
void ClassLoaderDataGraph::classes_do(void f(Klass* const)) {
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->classes_do(f);
}
}
void ClassLoaderDataGraph::methods_do(void f(Method*)) {
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->methods_do(f);
}
}
void ClassLoaderDataGraph::modules_do(void f(ModuleEntry*)) {
assert_locked_or_safepoint(Module_lock);
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->modules_do(f);
}
}
@ -1084,7 +1107,9 @@ void ClassLoaderDataGraph::modules_unloading_do(void f(ModuleEntry*)) {
void ClassLoaderDataGraph::packages_do(void f(PackageEntry*)) {
assert_locked_or_safepoint(Module_lock);
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->packages_do(f);
}
}
@ -1100,7 +1125,9 @@ void ClassLoaderDataGraph::packages_unloading_do(void f(PackageEntry*)) {
}
void ClassLoaderDataGraph::loaded_classes_do(KlassClosure* klass_closure) {
Thread* thread = Thread::current();
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
Handle holder(thread, cld->holder_phantom());
cld->loaded_classes_do(klass_closure);
}
}
@ -1121,21 +1148,27 @@ void ClassLoaderDataGraph::classes_unloading_do(void f(Klass* const)) {
// Walk classes in the loaded class dictionaries in various forms.
// Only walks the classes defined in this class loader.
void ClassLoaderDataGraph::dictionary_classes_do(void f(InstanceKlass*)) {
Thread* thread = Thread::current();
FOR_ALL_DICTIONARY(cld) {
Handle holder(thread, cld->holder_phantom());
cld->dictionary()->classes_do(f);
}
}
// Only walks the classes defined in this class loader.
void ClassLoaderDataGraph::dictionary_classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
Thread* thread = Thread::current();
FOR_ALL_DICTIONARY(cld) {
Handle holder(thread, cld->holder_phantom());
cld->dictionary()->classes_do(f, CHECK);
}
}
// Walks all entries in the dictionary including entries initiated by this class loader.
void ClassLoaderDataGraph::dictionary_all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
Thread* thread = Thread::current();
FOR_ALL_DICTIONARY(cld) {
Handle holder(thread, cld->holder_phantom());
cld->dictionary()->all_entries_do(f);
}
}