/*
* Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
// A ClassLoaderData identifies the full set of class types that a class
// loader's name resolution strategy produces for a given configuration of the
// class loader.
// Class types in the ClassLoaderData may be defined by from class file binaries
// provided by the class loader, or from other class loader it interacts with
// according to its name resolution strategy.
//
// Class loaders that implement a deterministic name resolution strategy
// (including with respect to their delegation behavior), such as the boot, the
// platform, and the system loaders of the JDK's built-in class loader
// hierarchy, always produce the same linkset for a given configuration.
//
// ClassLoaderData carries information related to a linkset (e.g.,
// metaspace holding its klass definitions).
// The System Dictionary and related data structures (e.g., placeholder table,
// loader constraints table) as well as the runtime representation of classes
// only reference ClassLoaderData.
//
// Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that
// that represent the loader's "linking domain" in the JVM.
//
// The bootstrap loader (represented by NULL) also has a ClassLoaderData,
// the singleton class the_null_class_loader_data().
#include "precompiled.hpp"
#include "classfile/classLoaderData.inline.hpp"
#include "classfile/classLoaderDataGraph.inline.hpp"
#include "classfile/dictionary.hpp"
#include "classfile/javaClasses.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/packageEntry.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/systemDictionary.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/metadataFactory.hpp"
#include "memory/resourceArea.hpp"
#include "oops/access.inline.hpp"
#include "oops/oop.inline.hpp"
#include "oops/oopHandle.inline.hpp"
#include "oops/weakHandle.inline.hpp"
#include "runtime/atomic.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/mutex.hpp"
#include "runtime/safepoint.hpp"
#include "utilities/growableArray.hpp"
#include "utilities/macros.hpp"
#include "utilities/ostream.hpp"
ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
void ClassLoaderData::init_null_class_loader_data() {
assert(_the_null_class_loader_data == NULL, "cannot initialize twice");
assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice");
_the_null_class_loader_data = new ClassLoaderData(Handle(), false);
ClassLoaderDataGraph::_head = _the_null_class_loader_data;
assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be");
LogTarget(Trace, class, loader, data) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
ls.print("create ");
_the_null_class_loader_data->print_value_on(&ls);
ls.cr();
}
}
// Obtain and set the class loader's name within the ClassLoaderData so
// it will be available for error messages, logging, JFR, etc. The name
// and klass are available after the class_loader oop is no longer alive,
// during unloading.
void ClassLoaderData::initialize_name(Handle class_loader) {
Thread* THREAD = Thread::current();
ResourceMark rm(THREAD);
// Obtain the class loader's name. If the class loader's name was not
// explicitly set during construction, the CLD's _name field will be null.
oop cl_name = java_lang_ClassLoader::name(class_loader());
if (cl_name != NULL) {
const char* cl_instance_name = java_lang_String::as_utf8_string(cl_name);
if (cl_instance_name != NULL && cl_instance_name[0] != '\0') {
_name = SymbolTable::new_symbol(cl_instance_name);
}
}
// Obtain the class loader's name and identity hash. If the class loader's
// name was not explicitly set during construction, the class loader's name and id
// will be set to the qualified class name of the class loader along with its
// identity hash.
// If for some reason the ClassLoader's constructor has not been run, instead of
// leaving the _name_and_id field null, fall back to the external qualified class
// name. Thus CLD's _name_and_id field should never have a null value.
oop cl_name_and_id = java_lang_ClassLoader::nameAndId(class_loader());
const char* cl_instance_name_and_id =
(cl_name_and_id == NULL) ? _class_loader_klass->external_name() :
java_lang_String::as_utf8_string(cl_name_and_id);
assert(cl_instance_name_and_id != NULL && cl_instance_name_and_id[0] != '\0', "class loader has no name and id");
_name_and_id = SymbolTable::new_symbol(cl_instance_name_and_id);
}
ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_unsafe_anonymous) :
_metaspace(NULL),
_metaspace_lock(new Mutex(Mutex::leaf+1, "Metaspace allocation lock", true,
Mutex::_safepoint_check_never)),
_unloading(false), _is_unsafe_anonymous(is_unsafe_anonymous),
_modified_oops(true), _accumulated_modified_oops(false),
// An unsafe anonymous class loader data doesn't have anything to keep
// it from being unloaded during parsing of the unsafe anonymous class.
// The null-class-loader should always be kept alive.
_keep_alive((is_unsafe_anonymous || h_class_loader.is_null()) ? 1 : 0),
_claim(0),
_handles(),
_klasses(NULL), _packages(NULL), _modules(NULL), _unnamed_module(NULL), _dictionary(NULL),
_jmethod_ids(NULL),
_deallocate_list(NULL),
_next(NULL),
_class_loader_klass(NULL), _name(NULL), _name_and_id(NULL) {
if (!h_class_loader.is_null()) {
_class_loader = _handles.add(h_class_loader());
_class_loader_klass = h_class_loader->klass();
initialize_name(h_class_loader);
}
if (!is_unsafe_anonymous) {
// The holder is initialized later for unsafe anonymous classes, and before calling anything
// that call class_loader().
initialize_holder(h_class_loader);
// A ClassLoaderData created solely for an unsafe anonymous class should never have a
// ModuleEntryTable or PackageEntryTable created for it. The defining package
// and module for an unsafe anonymous class will be found in its host class.
_packages = new PackageEntryTable(PackageEntryTable::_packagetable_entry_size);
if (h_class_loader.is_null()) {
// Create unnamed module for boot loader
_unnamed_module = ModuleEntry::create_boot_unnamed_module(this);
} else {
// Create unnamed module for all other loaders
_unnamed_module = ModuleEntry::create_unnamed_module(this);
}
_dictionary = create_dictionary();
}
NOT_PRODUCT(_dependency_count = 0); // number of class loader dependencies
JFR_ONLY(INIT_ID(this);)
}
ClassLoaderData::ChunkedHandleList::~ChunkedHandleList() {
Chunk* c = _head;
while (c != NULL) {
Chunk* next = c->_next;
delete c;
c = next;
}
}
oop* ClassLoaderData::ChunkedHandleList::add(oop o) {
if (_head == NULL || _head->_size == Chunk::CAPACITY) {
Chunk* next = new Chunk(_head);
Atomic::release_store(&_head, next);
}
oop* handle = &_head->_data[_head->_size];
NativeAccess<IS_DEST_UNINITIALIZED>::oop_store(handle, o);
Atomic::release_store(&_head->_size, _head->_size + 1);
return handle;
}
int ClassLoaderData::ChunkedHandleList::count() const {
int count = 0;
Chunk* chunk = _head;
while (chunk != NULL) {
count += chunk->_size;
chunk = chunk->_next;
}
return count;
}
inline void ClassLoaderData::ChunkedHandleList::oops_do_chunk(OopClosure* f, Chunk* c, const juint size) {
for (juint i = 0; i < size; i++) {
if (c->_data[i] != NULL) {
f->do_oop(&c->_data[i]);
}
}
}
void ClassLoaderData::ChunkedHandleList::oops_do(OopClosure* f) {
Chunk* head = Atomic::load_acquire(&_head);
if (head != NULL) {
// Must be careful when reading size of head
oops_do_chunk(f, head, Atomic::load_acquire(&head->_size));
for (Chunk* c = head->_next; c != NULL; c = c->_next) {
oops_do_chunk(f, c, c->_size);
}
}
}
class VerifyContainsOopClosure : public OopClosure {
oop _target;
bool _found;
public:
VerifyContainsOopClosure(oop target) : _target(target), _found(false) {}
void do_oop(oop* p) {
if (p != NULL && NativeAccess<AS_NO_KEEPALIVE>::oop_load(p) == _target) {
_found = true;
}
}
void do_oop(narrowOop* p) {
// The ChunkedHandleList should not contain any narrowOop
ShouldNotReachHere();
}
bool found() const {
return _found;
}
};
bool ClassLoaderData::ChunkedHandleList::contains(oop p) {
VerifyContainsOopClosure cl(p);
oops_do(&cl);
return cl.found();
}
#ifndef PRODUCT
bool ClassLoaderData::ChunkedHandleList::owner_of(oop* oop_handle) {
Chunk* chunk = _head;
while (chunk != NULL) {
if (&(chunk->_data[0]) <= oop_handle && oop_handle < &(chunk->_data[chunk->_size])) {
return true;
}
chunk = chunk->_next;
}
return false;
}
#endif // PRODUCT
void ClassLoaderData::clear_claim(int claim) {
for (;;) {
int old_claim = Atomic::load(&_claim);
if ((old_claim & claim) == 0) {
return;
}
int new_claim = old_claim & ~claim;
if (Atomic::cmpxchg(&_claim, old_claim, new_claim) == old_claim) {
return;
}
}
}
bool ClassLoaderData::try_claim(int claim) {
for (;;) {
int old_claim = Atomic::load(&_claim);
if ((old_claim & claim) == claim) {
return false;
}
int new_claim = old_claim | claim;
if (Atomic::cmpxchg(&_claim, old_claim, new_claim) == old_claim) {
return true;
}
}
}
// Unsafe anonymous classes have their own ClassLoaderData that is marked to keep alive
// while the class is being parsed, and if the class appears on the module fixup list.
// Due to the uniqueness that no other class shares the unsafe anonymous class' name or
// ClassLoaderData, no other non-GC thread has knowledge of the unsafe anonymous class while
// it is being defined, therefore _keep_alive is not volatile or atomic.
void ClassLoaderData::inc_keep_alive() {
if (is_unsafe_anonymous()) {
assert(_keep_alive > 0, "Invalid keep alive increment count");
_keep_alive++;
}
}
void ClassLoaderData::dec_keep_alive() {
if (is_unsafe_anonymous()) {
assert(_keep_alive > 0, "Invalid keep alive decrement count");
_keep_alive--;
}
}
void ClassLoaderData::oops_do(OopClosure* f, int claim_value, bool clear_mod_oops) {
if (claim_value != ClassLoaderData::_claim_none && !try_claim(claim_value)) {
return;
}
// Only clear modified_oops after the ClassLoaderData is claimed.
if (clear_mod_oops) {
clear_modified_oops();
}
_handles.oops_do(f);
}
void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
klass_closure->do_klass(k);
assert(k != k->next_link(), "no loops!");
}
}
void ClassLoaderData::classes_do(void f(Klass * const)) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
f(k);
assert(k != k->next_link(), "no loops!");
}
}
void ClassLoaderData::methods_do(void f(Method*)) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
if (k->is_instance_klass() && InstanceKlass::cast(k)->is_loaded()) {
InstanceKlass::cast(k)->methods_do(f);
}
}
}
void ClassLoaderData::loaded_classes_do(KlassClosure* klass_closure) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
// Do not filter ArrayKlass oops here...
if (k->is_array_klass() || (k->is_instance_klass() && InstanceKlass::cast(k)->is_loaded())) {
#ifdef ASSERT
oop m = k->java_mirror();
assert(m != NULL, "NULL mirror");
assert(m->is_a(SystemDictionary::Class_klass()), "invalid mirror");
#endif
klass_closure->do_klass(k);
}
}
}
void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
if (k->is_instance_klass()) {
f(InstanceKlass::cast(k));
}
assert(k != k->next_link(), "no loops!");
}
}
void ClassLoaderData::modules_do(void f(ModuleEntry*)) {
assert_locked_or_safepoint(Module_lock);
if (_unnamed_module != NULL) {
f(_unnamed_module);
}
if (_modules != NULL) {
for (int i = 0; i < _modules->table_size(); i++) {
for (ModuleEntry* entry = _modules->bucket(i);
entry != NULL;
entry = entry->next()) {
f(entry);
}
}
}
}
void ClassLoaderData::packages_do(void f(PackageEntry*)) {
assert_locked_or_safepoint(Module_lock);
if (_packages != NULL) {
for (int i = 0; i < _packages->table_size(); i++) {
for (PackageEntry* entry = _packages->bucket(i);
entry != NULL;
entry = entry->next()) {
f(entry);
}
}
}
}
void ClassLoaderData::record_dependency(const Klass* k) {
assert(k != NULL, "invariant");
ClassLoaderData * const from_cld = this;
ClassLoaderData * const to_cld = k->class_loader_data();
// Do not need to record dependency if the dependency is to a class whose
// class loader data is never freed. (i.e. the dependency's class loader
// is one of the three builtin class loaders and the dependency is not
// unsafe anonymous.)
if (to_cld->is_permanent_class_loader_data()) {
return;
}
oop to;
if (to_cld->is_unsafe_anonymous()) {
// Just return if an unsafe anonymous class is attempting to record a dependency
// to itself. (Note that every unsafe anonymous class has its own unique class
// loader data.)
if (to_cld == from_cld) {
return;
}
// Unsafe anonymous class dependencies are through the mirror.
to = k->java_mirror();
} else {
to = to_cld->class_loader();
oop from = from_cld->class_loader();
// Just return if this dependency is to a class with the same or a parent
// class_loader.
if (from == to || java_lang_ClassLoader::isAncestor(from, to)) {
return; // this class loader is in the parent list, no need to add it.
}
}
// It's a dependency we won't find through GC, add it.
if (!_handles.contains(to)) {
NOT_PRODUCT(Atomic::inc(&_dependency_count));
LogTarget(Trace, class, loader, data) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
ls.print("adding dependency from ");
print_value_on(&ls);
ls.print(" to ");
to_cld->print_value_on(&ls);
ls.cr();
}
Handle dependency(Thread::current(), to);
add_handle(dependency);
// Added a potentially young gen oop to the ClassLoaderData
record_modified_oops();
}
}
void ClassLoaderData::add_class(Klass* k, bool publicize /* true */) {
{
MutexLocker ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
Klass* old_value = _klasses;
k->set_next_link(old_value);
// Link the new item into the list, making sure the linked class is stable
// since the list can be walked without a lock
Atomic::release_store(&_klasses, k);
if (k->is_array_klass()) {
ClassLoaderDataGraph::inc_array_classes(1);
} else {
ClassLoaderDataGraph::inc_instance_classes(1);
}
}
if (publicize) {
LogTarget(Trace, class, loader, data) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
ls.print("Adding k: " PTR_FORMAT " %s to ", p2i(k), k->external_name());
print_value_on(&ls);
ls.cr();
}
}
}
void ClassLoaderData::initialize_holder(Handle loader_or_mirror) {
if (loader_or_mirror() != NULL) {
assert(_holder.is_null(), "never replace holders");
_holder = WeakHandle<vm_class_loader_data>::create(loader_or_mirror);
}
}
// Remove a klass from the _klasses list for scratch_class during redefinition
// or parsed class in the case of an error.
void ClassLoaderData::remove_class(Klass* scratch_class) {
assert_locked_or_safepoint(ClassLoaderDataGraph_lock);
// Adjust global class iterator.
ClassLoaderDataGraph::adjust_saved_class(scratch_class);
Klass* prev = NULL;
for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
if (k == scratch_class) {
if (prev == NULL) {
_klasses = k->next_link();
} else {
Klass* next = k->next_link();
prev->set_next_link(next);
}
if (k->is_array_klass()) {
ClassLoaderDataGraph::dec_array_classes(1);
} else {
ClassLoaderDataGraph::dec_instance_classes(1);
}
return;
}
prev = k;
assert(k != k->next_link(), "no loops!");
}
ShouldNotReachHere(); // should have found this class!!
}
void ClassLoaderData::unload() {
_unloading = true;
LogTarget(Trace, class, loader, data) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
ls.print("unload");
print_value_on(&ls);
ls.cr();
}
// Some items on the _deallocate_list need to free their C heap structures
// if they are not already on the _klasses list.
free_deallocate_list_C_heap_structures();
// Clean up class dependencies and tell serviceability tools
// these classes are unloading. Must be called
// after erroneous classes are released.
classes_do(InstanceKlass::unload_class);
// Clean up global class iterator for compiler
ClassLoaderDataGraph::adjust_saved_class(this);
}
ModuleEntryTable* ClassLoaderData::modules() {
// Lazily create the module entry table at first request.
// Lock-free access requires load_acquire.
ModuleEntryTable* modules = Atomic::load_acquire(&_modules);
if (modules == NULL) {
MutexLocker m1(Module_lock);
// Check if _modules got allocated while we were waiting for this lock.
if ((modules = _modules) == NULL) {
modules = new ModuleEntryTable(ModuleEntryTable::_moduletable_entry_size);
{
MutexLocker m1(metaspace_lock(), Mutex::_no_safepoint_check_flag);
// Ensure _modules is stable, since it is examined without a lock
Atomic::release_store(&_modules, modules);
}
}
}
return modules;
}
const int _boot_loader_dictionary_size = 1009;
const int _default_loader_dictionary_size = 107;
Dictionary* ClassLoaderData::create_dictionary() {
assert(!is_unsafe_anonymous(), "unsafe anonymous class loader data do not have a dictionary");
int size;
bool resizable = false;
if (_the_null_class_loader_data == NULL) {
size = _boot_loader_dictionary_size;
resizable = true;
} else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) {
size = 1; // there's only one class in relection class loader and no initiated classes
} else if (is_system_class_loader_data()) {
size = _boot_loader_dictionary_size;
resizable = true;
} else {
size = _default_loader_dictionary_size;
resizable = true;
}
if (!DynamicallyResizeSystemDictionaries || DumpSharedSpaces) {
resizable = false;
}
return new Dictionary(this, size, resizable);
}
// Tell the GC to keep this klass alive while iterating ClassLoaderDataGraph
oop ClassLoaderData::holder_phantom() const {
// 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 (!_holder.is_null()) { // NULL class_loader
return _holder.resolve();
} else {
return NULL;
}
}
// Let the GC read the holder without keeping it alive.
oop ClassLoaderData::holder_no_keepalive() const {
if (!_holder.is_null()) { // NULL class_loader
return _holder.peek();
} else {
return NULL;
}
}
// Unloading support
bool ClassLoaderData::is_alive() const {
bool alive = keep_alive() // null class loader and incomplete unsafe anonymous klasses.
|| (_holder.peek() != NULL); // and not cleaned by the GC weak handle processing.
return alive;
}
class ReleaseKlassClosure: public KlassClosure {
private:
size_t _instance_class_released;
size_t _array_class_released;
public:
ReleaseKlassClosure() : _instance_class_released(0), _array_class_released(0) { }
size_t instance_class_released() const { return _instance_class_released; }
size_t array_class_released() const { return _array_class_released; }
void do_klass(Klass* k) {
if (k->is_array_klass()) {
_array_class_released ++;
} else {
assert(k->is_instance_klass(), "Must be");
_instance_class_released ++;
InstanceKlass::release_C_heap_structures(InstanceKlass::cast(k));
}
}
};
ClassLoaderData::~ClassLoaderData() {
// Release C heap structures for all the classes.
ReleaseKlassClosure cl;
classes_do(&cl);
ClassLoaderDataGraph::dec_array_classes(cl.array_class_released());
ClassLoaderDataGraph::dec_instance_classes(cl.instance_class_released());
// Release the WeakHandle
_holder.release();
// Release C heap allocated hashtable for all the packages.
if (_packages != NULL) {
// Destroy the table itself
delete _packages;
_packages = NULL;
}
// Release C heap allocated hashtable for all the modules.
if (_modules != NULL) {
// Destroy the table itself
delete _modules;
_modules = NULL;
}
// Release C heap allocated hashtable for the dictionary
if (_dictionary != NULL) {
// Destroy the table itself
delete _dictionary;
_dictionary = NULL;
}
if (_unnamed_module != NULL) {
_unnamed_module->delete_unnamed_module();
_unnamed_module = NULL;
}
// release the metaspace
ClassLoaderMetaspace *m = _metaspace;
if (m != NULL) {
_metaspace = NULL;
delete m;
}
// Clear all the JNI handles for methods
// These aren't deallocated and are going to look like a leak, but that's
// needed because we can't really get rid of jmethodIDs because we don't
// know when native code is going to stop using them. The spec says that
// they're "invalid" but existing programs likely rely on their being
// NULL after class unloading.
if (_jmethod_ids != NULL) {
Method::clear_jmethod_ids(this);
}
// Delete lock
delete _metaspace_lock;
// Delete free list
if (_deallocate_list != NULL) {
delete _deallocate_list;
}
// Decrement refcounts of Symbols if created.
if (_name != NULL) {
_name->decrement_refcount();
}
if (_name_and_id != NULL) {
_name_and_id->decrement_refcount();
}
}
// Returns true if this class loader data is for the app class loader
// or a user defined system class loader. (Note that the class loader
// data may be unsafe anonymous.)
bool ClassLoaderData::is_system_class_loader_data() const {
return SystemDictionary::is_system_class_loader(class_loader());
}
// Returns true if this class loader data is for the platform class loader.
// (Note that the class loader data may be unsafe anonymous.)
bool ClassLoaderData::is_platform_class_loader_data() const {
return SystemDictionary::is_platform_class_loader(class_loader());
}
// Returns true if the class loader for this class loader data is one of
// the 3 builtin (boot application/system or platform) class loaders,
// including a user-defined system class loader. Note that if the class
// loader data is for an unsafe anonymous class then it may get freed by a GC
// even if its class loader is one of these loaders.
bool ClassLoaderData::is_builtin_class_loader_data() const {
return (is_boot_class_loader_data() ||
SystemDictionary::is_system_class_loader(class_loader()) ||
SystemDictionary::is_platform_class_loader(class_loader()));
}
// Returns true if this class loader data is a class loader data
// that is not ever freed by a GC. It must be the CLD for one of the builtin
// class loaders and not the CLD for an unsafe anonymous class.
bool ClassLoaderData::is_permanent_class_loader_data() const {
return is_builtin_class_loader_data() && !is_unsafe_anonymous();
}
ClassLoaderMetaspace* ClassLoaderData::metaspace_non_null() {
// If the metaspace has not been allocated, create a new one. Might want
// to create smaller arena for Reflection class loaders also.
// The reason for the delayed allocation is because some class loaders are
// simply for delegating with no metadata of their own.
// Lock-free access requires load_acquire.
ClassLoaderMetaspace* metaspace = Atomic::load_acquire(&_metaspace);
if (metaspace == NULL) {
MutexLocker ml(_metaspace_lock, Mutex::_no_safepoint_check_flag);
// Check if _metaspace got allocated while we were waiting for this lock.
if ((metaspace = _metaspace) == NULL) {
if (this == the_null_class_loader_data()) {
assert (class_loader() == NULL, "Must be");
metaspace = new ClassLoaderMetaspace(_metaspace_lock, Metaspace::BootMetaspaceType);
} else if (is_unsafe_anonymous()) {
metaspace = new ClassLoaderMetaspace(_metaspace_lock, Metaspace::UnsafeAnonymousMetaspaceType);
} else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) {
metaspace = new ClassLoaderMetaspace(_metaspace_lock, Metaspace::ReflectionMetaspaceType);
} else {
metaspace = new ClassLoaderMetaspace(_metaspace_lock, Metaspace::StandardMetaspaceType);
}
// Ensure _metaspace is stable, since it is examined without a lock
Atomic::release_store(&_metaspace, metaspace);
}
}
return metaspace;
}
OopHandle ClassLoaderData::add_handle(Handle h) {
MutexLocker ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
record_modified_oops();
return OopHandle(_handles.add(h()));
}
void ClassLoaderData::remove_handle(OopHandle h) {
assert(!is_unloading(), "Do not remove a handle for a CLD that is unloading");
oop* ptr = h.ptr_raw();
if (ptr != NULL) {
assert(_handles.owner_of(ptr), "Got unexpected handle " PTR_FORMAT, p2i(ptr));
NativeAccess<>::oop_store(ptr, oop(NULL));
}
}
void ClassLoaderData::init_handle_locked(OopHandle& dest, Handle h) {
MutexLocker ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
if (dest.resolve() != NULL) {
return;
} else {
dest = _handles.add(h());
}
}
// Add this metadata pointer to be freed when it's safe. This is only during
// a safepoint which checks if handles point to this metadata field.
void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
// Metadata in shared region isn't deleted.
if (!m->is_shared()) {
MutexLocker ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
if (_deallocate_list == NULL) {
_deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
}
_deallocate_list->append_if_missing(m);
log_debug(class, loader, data)("deallocate added for %s", m->print_value_string());
ClassLoaderDataGraph::set_should_clean_deallocate_lists();
}
}
// Deallocate free metadata on the free list. How useful the PermGen was!
void ClassLoaderData::free_deallocate_list() {
// This must be called at a safepoint because it depends on metadata walking at
// safepoint cleanup time.
assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
assert(!is_unloading(), "only called for ClassLoaderData that are not unloading");
if (_deallocate_list == NULL) {
return;
}
// Go backwards because this removes entries that are freed.
for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
Metadata* m = _deallocate_list->at(i);
if (!m->on_stack()) {
_deallocate_list->remove_at(i);
// There are only three types of metadata that we deallocate directly.
// Cast them so they can be used by the template function.
if (m->is_method()) {
MetadataFactory::free_metadata(this, (Method*)m);
} else if (m->is_constantPool()) {
MetadataFactory::free_metadata(this, (ConstantPool*)m);
} else if (m->is_klass()) {
MetadataFactory::free_metadata(this, (InstanceKlass*)m);
} else {
ShouldNotReachHere();
}
} else {
// Metadata is alive.
// If scratch_class is on stack then it shouldn't be on this list!
assert(!m->is_klass() || !((InstanceKlass*)m)->is_scratch_class(),
"scratch classes on this list should be dead");
// Also should assert that other metadata on the list was found in handles.
// Some cleaning remains.
ClassLoaderDataGraph::set_should_clean_deallocate_lists();
}
}
}
// This is distinct from free_deallocate_list. For class loader data that are
// unloading, this frees the C heap memory for items on the list, and unlinks
// scratch or error classes so that unloading events aren't triggered for these
// classes. The metadata is removed with the unloading metaspace.
// There isn't C heap memory allocated for methods, so nothing is done for them.
void ClassLoaderData::free_deallocate_list_C_heap_structures() {
assert_locked_or_safepoint(ClassLoaderDataGraph_lock);
assert(is_unloading(), "only called for ClassLoaderData that are unloading");
if (_deallocate_list == NULL) {
return;
}
// Go backwards because this removes entries that are freed.
for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
Metadata* m = _deallocate_list->at(i);
_deallocate_list->remove_at(i);
if (m->is_constantPool()) {
((ConstantPool*)m)->release_C_heap_structures();
} else if (m->is_klass()) {
InstanceKlass* ik = (InstanceKlass*)m;
// also releases ik->constants() C heap memory
InstanceKlass::release_C_heap_structures(ik);
// Remove the class so unloading events aren't triggered for
// this class (scratch or error class) in do_unloading().
remove_class(ik);
}
}
}
// These CLDs are to contain unsafe anonymous classes used for JSR292
ClassLoaderData* ClassLoaderData::unsafe_anonymous_class_loader_data(Handle loader) {
// Add a new class loader data to the graph.
return ClassLoaderDataGraph::add(loader, true);
}
// Caller needs ResourceMark
// If the class loader's _name has not been explicitly set, the class loader's
// qualified class name is returned.
const char* ClassLoaderData::loader_name() const {
if (_class_loader_klass == NULL) {
return BOOTSTRAP_LOADER_NAME;
} else if (_name != NULL) {
return _name->as_C_string();
} else {
return _class_loader_klass->external_name();
}
}
// Caller needs ResourceMark
// Format of the _name_and_id is as follows:
// If the defining loader has a name explicitly set then '<loader-name>' @<id>
// If the defining loader has no name then <qualified-class-name> @<id>
// If built-in loader, then omit '@<id>' as there is only one instance.
const char* ClassLoaderData::loader_name_and_id() const {
if (_class_loader_klass == NULL) {
return "'" BOOTSTRAP_LOADER_NAME "'";
} else if (_name_and_id != NULL) {
return _name_and_id->as_C_string();
} else {
// May be called in a race before _name_and_id is initialized.
return _class_loader_klass->external_name();
}
}
void ClassLoaderData::print_value_on(outputStream* out) const {
if (!is_unloading() && class_loader() != NULL) {
out->print("loader data: " INTPTR_FORMAT " for instance ", p2i(this));
class_loader()->print_value_on(out); // includes loader_name_and_id() and address of class loader instance
} else {
// loader data: 0xsomeaddr of 'bootstrap'
out->print("loader data: " INTPTR_FORMAT " of %s", p2i(this), loader_name_and_id());
}
if (is_unsafe_anonymous()) {
out->print(" unsafe anonymous");
}
}
void ClassLoaderData::print_value() const { print_value_on(tty); }
#ifndef PRODUCT
void ClassLoaderData::print_on(outputStream* out) const {
out->print("ClassLoaderData CLD: " PTR_FORMAT ", loader: " PTR_FORMAT ", loader_klass: %s {",
p2i(this), p2i(_class_loader.ptr_raw()), loader_name_and_id());
if (is_unsafe_anonymous()) out->print(" unsafe anonymous");
if (claimed()) out->print(" claimed");
if (is_unloading()) out->print(" unloading");
out->print(" metaspace: " INTPTR_FORMAT, p2i(metaspace_or_null()));
if (_jmethod_ids != NULL) {
Method::print_jmethod_ids(this, out);
}
out->print(" handles count %d", _handles.count());
out->print(" dependencies %d", _dependency_count);
out->print_cr("}");
}
#endif // PRODUCT
void ClassLoaderData::print() const { print_on(tty); }
void ClassLoaderData::verify() {
assert_locked_or_safepoint(_metaspace_lock);
oop cl = class_loader();
guarantee(this == class_loader_data(cl) || is_unsafe_anonymous(), "Must be the same");
guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_unsafe_anonymous(), "must be");
// Verify the integrity of the allocated space.
if (metaspace_or_null() != NULL) {
metaspace_or_null()->verify();
}
for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
guarantee(k->class_loader_data() == this, "Must be the same");
k->verify();
assert(k != k->next_link(), "no loops!");
}
}
bool ClassLoaderData::contains_klass(Klass* klass) {
// Lock-free access requires load_acquire
for (Klass* k = Atomic::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
if (k == klass) return true;
}
return false;
}