6964458: Reimplement class meta-data storage to use native memory
Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>
/*
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* 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).
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "precompiled.hpp"
#include "classfile/javaClasses.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "jvmtifiles/jvmti.h"
#include "memory/gcLocker.hpp"
#include "memory/universe.inline.hpp"
#include "oops/arrayKlass.hpp"
#include "oops/arrayOop.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/objArrayOop.hpp"
#include "oops/oop.inline.hpp"
int arrayKlass::static_size(int header_size) {
// size of an array klass object
assert(header_size <= InstanceKlass::header_size(), "bad header size");
// If this assert fails, see comments in base_create_array_klass.
header_size = InstanceKlass::header_size();
int vtable_len = Universe::base_vtable_size();
#ifdef _LP64
int size = header_size + align_object_offset(vtable_len);
#else
int size = header_size + vtable_len;
#endif
return align_object_size(size);
}
Klass* arrayKlass::java_super() const {
if (super() == NULL) return NULL; // bootstrap case
// Array klasses have primary supertypes which are not reported to Java.
// Example super chain: String[][] -> Object[][] -> Object[] -> Object
return SystemDictionary::Object_klass();
}
oop arrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) {
ShouldNotReachHere();
return NULL;
}
Method* arrayKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
// There are no methods in an array klass but the super class (Object) has some
assert(super(), "super klass must be present");
return Klass::cast(super())->uncached_lookup_method(name, signature);
}
arrayKlass::arrayKlass(Symbol* name) {
set_alloc_size(0);
set_name(name);
set_super(Universe::is_bootstrapping() ? (Klass*)NULL : SystemDictionary::Object_klass());
set_layout_helper(Klass::_lh_neutral_value);
set_dimension(1);
set_higher_dimension(NULL);
set_lower_dimension(NULL);
set_component_mirror(NULL);
// Arrays don't add any new methods, so their vtable is the same size as
// the vtable of klass Object.
int vtable_size = Universe::base_vtable_size();
set_vtable_length(vtable_size);
set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5)
}
// Initialization of vtables and mirror object is done separatly from base_create_array_klass,
// since a GC can happen. At this point all instance variables of the arrayKlass must be setup.
void arrayKlass::complete_create_array_klass(arrayKlass* k, KlassHandle super_klass, TRAPS) {
ResourceMark rm(THREAD);
k->initialize_supers(super_klass(), CHECK);
k->vtable()->initialize_vtable(false, CHECK);
java_lang_Class::create_mirror(k, CHECK);
}
GrowableArray<Klass*>* arrayKlass::compute_secondary_supers(int num_extra_slots) {
// interfaces = { cloneable_klass, serializable_klass };
assert(num_extra_slots == 0, "sanity of primitive array type");
// Must share this for correct bootstrapping!
set_secondary_supers(Universe::the_array_interfaces_array());
return NULL;
}
bool arrayKlass::compute_is_subtype_of(Klass* k) {
// An array is a subtype of Serializable, Clonable, and Object
return k == SystemDictionary::Object_klass()
|| k == SystemDictionary::Cloneable_klass()
|| k == SystemDictionary::Serializable_klass();
}
inline intptr_t* arrayKlass::start_of_vtable() const {
// all vtables start at the same place, that's why we use InstanceKlass::header_size here
return ((intptr_t*)this) + InstanceKlass::header_size();
}
klassVtable* arrayKlass::vtable() const {
KlassHandle kh(Thread::current(), this);
return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size());
}
objArrayOop arrayKlass::allocate_arrayArray(int n, int length, TRAPS) {
if (length < 0) {
THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
}
if (length > arrayOopDesc::max_array_length(T_ARRAY)) {
report_java_out_of_memory("Requested array size exceeds VM limit");
JvmtiExport::post_array_size_exhausted();
THROW_OOP_0(Universe::out_of_memory_error_array_size());
}
int size = objArrayOopDesc::object_size(length);
Klass* k = array_klass(n+dimension(), CHECK_0);
arrayKlass* ak = arrayKlass::cast(k);
objArrayOop o =
(objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0);
// initialization to NULL not necessary, area already cleared
return o;
}
void arrayKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
Klass* k = this;
// Iterate over this array klass and all higher dimensions
while (k != NULL) {
f(k, CHECK);
k = arrayKlass::cast(k)->higher_dimension();
}
}
void arrayKlass::array_klasses_do(void f(Klass* k)) {
Klass* k = this;
// Iterate over this array klass and all higher dimensions
while (k != NULL) {
f(k);
k = arrayKlass::cast(k)->higher_dimension();
}
}
void arrayKlass::with_array_klasses_do(void f(Klass* k)) {
array_klasses_do(f);
}
// GC support
void arrayKlass::oops_do(OopClosure* cl) {
Klass::oops_do(cl);
cl->do_oop(adr_component_mirror());
}
// JVM support
jint arrayKlass::compute_modifier_flags(TRAPS) const {
return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC;
}
// JVMTI support
jint arrayKlass::jvmti_class_status() const {
return JVMTI_CLASS_STATUS_ARRAY;
}
void arrayKlass::remove_unshareable_info() {
Klass::remove_unshareable_info();
// Clear the java mirror
set_component_mirror(NULL);
}
void arrayKlass::restore_unshareable_info(TRAPS) {
Klass::restore_unshareable_info(CHECK);
// Klass recreates the component mirror also
}
// Printing
void arrayKlass::print_on(outputStream* st) const {
assert(is_klass(), "must be klass");
Klass::print_on(st);
}
void arrayKlass::print_value_on(outputStream* st) const {
assert(is_klass(), "must be klass");
for(int index = 0; index < dimension(); index++) {
st->print("[]");
}
}
void arrayKlass::oop_print_on(oop obj, outputStream* st) {
assert(obj->is_array(), "must be array");
Klass::oop_print_on(obj, st);
st->print_cr(" - length: %d", arrayOop(obj)->length());
}
// Verification
void arrayKlass::verify_on(outputStream* st) {
Klass::verify_on(st);
if (component_mirror() != NULL) {
guarantee(component_mirror()->klass() != NULL, "should have a class");
}
}
void arrayKlass::oop_verify_on(oop obj, outputStream* st) {
guarantee(obj->is_array(), "must be array");
arrayOop a = arrayOop(obj);
guarantee(a->length() >= 0, "array with negative length?");
}