1641 lines
66 KiB
C++
1641 lines
66 KiB
C++
/*
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* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "jvm.h"
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#include "classfile/javaClasses.hpp"
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#include "classfile/systemDictionary.hpp"
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#include "classfile/vmSymbols.hpp"
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#include "interpreter/linkResolver.hpp"
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#include "logging/log.hpp"
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#include "logging/logStream.hpp"
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#include "memory/metaspaceShared.hpp"
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#include "memory/resourceArea.hpp"
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#include "memory/universe.hpp"
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#include "oops/instanceKlass.hpp"
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#include "oops/klassVtable.hpp"
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#include "oops/method.hpp"
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#include "oops/objArrayOop.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/arguments.hpp"
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#include "runtime/flags/flagSetting.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/safepointVerifiers.hpp"
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#include "utilities/copy.hpp"
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inline InstanceKlass* klassVtable::ik() const {
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return InstanceKlass::cast(_klass);
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}
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bool klassVtable::is_preinitialized_vtable() {
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return _klass->is_shared() && !MetaspaceShared::remapped_readwrite();
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}
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// this function computes the vtable size (including the size needed for miranda
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// methods) and the number of miranda methods in this class.
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// Note on Miranda methods: Let's say there is a class C that implements
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// interface I, and none of C's superclasses implements I.
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// Let's say there is an abstract method m in I that neither C
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// nor any of its super classes implement (i.e there is no method of any access,
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// with the same name and signature as m), then m is a Miranda method which is
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// entered as a public abstract method in C's vtable. From then on it should
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// treated as any other public method in C for method over-ride purposes.
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void klassVtable::compute_vtable_size_and_num_mirandas(
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int* vtable_length_ret, int* num_new_mirandas,
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GrowableArray<Method*>* all_mirandas, const Klass* super,
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Array<Method*>* methods, AccessFlags class_flags, u2 major_version,
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Handle classloader, Symbol* classname, Array<InstanceKlass*>* local_interfaces,
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TRAPS) {
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NoSafepointVerifier nsv;
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// set up default result values
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int vtable_length = 0;
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// start off with super's vtable length
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vtable_length = super == NULL ? 0 : super->vtable_length();
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// go thru each method in the methods table to see if it needs a new entry
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int len = methods->length();
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for (int i = 0; i < len; i++) {
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assert(methods->at(i)->is_method(), "must be a Method*");
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methodHandle mh(THREAD, methods->at(i));
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if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, major_version, THREAD)) {
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vtable_length += vtableEntry::size(); // we need a new entry
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}
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}
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GrowableArray<Method*> new_mirandas(20);
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// compute the number of mirandas methods that must be added to the end
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get_mirandas(&new_mirandas, all_mirandas, super, methods, NULL, local_interfaces,
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class_flags.is_interface());
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*num_new_mirandas = new_mirandas.length();
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// Interfaces do not need interface methods in their vtables
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// This includes miranda methods and during later processing, default methods
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if (!class_flags.is_interface()) {
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vtable_length += *num_new_mirandas * vtableEntry::size();
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}
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if (Universe::is_bootstrapping() && vtable_length == 0) {
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// array classes don't have their superclass set correctly during
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// bootstrapping
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vtable_length = Universe::base_vtable_size();
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}
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if (super == NULL && vtable_length != Universe::base_vtable_size()) {
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if (Universe::is_bootstrapping()) {
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// Someone is attempting to override java.lang.Object incorrectly on the
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// bootclasspath. The JVM cannot recover from this error including throwing
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// an exception
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vm_exit_during_initialization("Incompatible definition of java.lang.Object");
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} else {
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// Someone is attempting to redefine java.lang.Object incorrectly. The
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// only way this should happen is from
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// SystemDictionary::resolve_from_stream(), which will detect this later
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// and throw a security exception. So don't assert here to let
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// the exception occur.
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vtable_length = Universe::base_vtable_size();
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}
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}
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assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
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assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
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*vtable_length_ret = vtable_length;
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}
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int klassVtable::index_of(Method* m, int len) const {
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assert(m->has_vtable_index(), "do not ask this of non-vtable methods");
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return m->vtable_index();
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}
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// Copy super class's vtable to the first part (prefix) of this class's vtable,
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// and return the number of entries copied. Expects that 'super' is the Java
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// super class (arrays can have "array" super classes that must be skipped).
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int klassVtable::initialize_from_super(Klass* super) {
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if (super == NULL) {
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return 0;
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} else if (is_preinitialized_vtable()) {
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// A shared class' vtable is preinitialized at dump time. No need to copy
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// methods from super class for shared class, as that was already done
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// during archiving time. However, if Jvmti has redefined a class,
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// copy super class's vtable in case the super class has changed.
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return super->vtable().length();
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} else {
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// copy methods from superKlass
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klassVtable superVtable = super->vtable();
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assert(superVtable.length() <= _length, "vtable too short");
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#ifdef ASSERT
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superVtable.verify(tty, true);
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#endif
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superVtable.copy_vtable_to(table());
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if (log_develop_is_enabled(Trace, vtables)) {
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ResourceMark rm;
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log_develop_trace(vtables)("copy vtable from %s to %s size %d",
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super->internal_name(), klass()->internal_name(),
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_length);
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}
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return superVtable.length();
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}
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}
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//
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// Revised lookup semantics introduced 1.3 (Kestrel beta)
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void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
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// Note: Arrays can have intermediate array supers. Use java_super to skip them.
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InstanceKlass* super = _klass->java_super();
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int nofNewEntries = 0;
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bool is_shared = _klass->is_shared();
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if (!_klass->is_array_klass()) {
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ResourceMark rm(THREAD);
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log_develop_debug(vtables)("Initializing: %s", _klass->name()->as_C_string());
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}
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#ifdef ASSERT
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oop* end_of_obj = (oop*)_klass + _klass->size();
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oop* end_of_vtable = (oop*)&table()[_length];
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assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
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#endif
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if (Universe::is_bootstrapping()) {
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assert(!is_shared, "sanity");
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// just clear everything
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for (int i = 0; i < _length; i++) table()[i].clear();
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return;
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}
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int super_vtable_len = initialize_from_super(super);
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if (_klass->is_array_klass()) {
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assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
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} else {
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assert(_klass->is_instance_klass(), "must be InstanceKlass");
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Array<Method*>* methods = ik()->methods();
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int len = methods->length();
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int initialized = super_vtable_len;
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// Check each of this class's methods against super;
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// if override, replace in copy of super vtable, otherwise append to end
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for (int i = 0; i < len; i++) {
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// update_inherited_vtable can stop for gc - ensure using handles
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HandleMark hm(THREAD);
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assert(methods->at(i)->is_method(), "must be a Method*");
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methodHandle mh(THREAD, methods->at(i));
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bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, -1, checkconstraints, CHECK);
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if (needs_new_entry) {
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put_method_at(mh(), initialized);
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mh()->set_vtable_index(initialized); // set primary vtable index
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initialized++;
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}
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}
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// update vtable with default_methods
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Array<Method*>* default_methods = ik()->default_methods();
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if (default_methods != NULL) {
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len = default_methods->length();
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if (len > 0) {
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Array<int>* def_vtable_indices = NULL;
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if ((def_vtable_indices = ik()->default_vtable_indices()) == NULL) {
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assert(!is_shared, "shared class def_vtable_indices does not exist");
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def_vtable_indices = ik()->create_new_default_vtable_indices(len, CHECK);
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} else {
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assert(def_vtable_indices->length() == len, "reinit vtable len?");
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}
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for (int i = 0; i < len; i++) {
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HandleMark hm(THREAD);
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assert(default_methods->at(i)->is_method(), "must be a Method*");
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methodHandle mh(THREAD, default_methods->at(i));
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assert(!mh->is_private(), "private interface method in the default method list");
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bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, i, checkconstraints, CHECK);
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// needs new entry
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if (needs_new_entry) {
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put_method_at(mh(), initialized);
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if (is_preinitialized_vtable()) {
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// At runtime initialize_vtable is rerun for a shared class
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// (loaded by the non-boot loader) as part of link_class_impl().
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// The dumptime vtable index should be the same as the runtime index.
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assert(def_vtable_indices->at(i) == initialized,
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"dump time vtable index is different from runtime index");
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} else {
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def_vtable_indices->at_put(i, initialized); //set vtable index
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}
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initialized++;
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}
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}
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}
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}
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// add miranda methods; it will also return the updated initialized
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// Interfaces do not need interface methods in their vtables
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// This includes miranda methods and during later processing, default methods
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if (!ik()->is_interface()) {
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initialized = fill_in_mirandas(initialized, THREAD);
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}
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// In class hierarchies where the accessibility is not increasing (i.e., going from private ->
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// package_private -> public/protected), the vtable might actually be smaller than our initial
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// calculation, for classfile versions for which we do not do transitive override
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// calculations.
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if (ik()->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) {
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assert(initialized == _length, "vtable initialization failed");
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} else {
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assert(initialized <= _length, "vtable initialization failed");
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for(;initialized < _length; initialized++) {
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table()[initialized].clear();
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}
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}
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NOT_PRODUCT(verify(tty, true));
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}
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}
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// Called for cases where a method does not override its superclass' vtable entry
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// For bytecodes not produced by javac together it is possible that a method does not override
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// the superclass's method, but might indirectly override a super-super class's vtable entry
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// If none found, return a null superk, else return the superk of the method this does override
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// For public and protected methods: if they override a superclass, they will
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// also be overridden themselves appropriately.
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// Private methods do not override and are not overridden.
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// Package Private methods are trickier:
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// e.g. P1.A, pub m
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// P2.B extends A, package private m
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// P1.C extends B, public m
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// P1.C.m needs to override P1.A.m and can not override P2.B.m
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// Therefore: all package private methods need their own vtable entries for
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// them to be the root of an inheritance overriding decision
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// Package private methods may also override other vtable entries
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InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, const methodHandle& target_method,
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int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
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InstanceKlass* superk = initialsuper;
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while (superk != NULL && superk->super() != NULL) {
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InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
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klassVtable ssVtable = supersuperklass->vtable();
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if (vtable_index < ssVtable.length()) {
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Method* super_method = ssVtable.method_at(vtable_index);
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#ifndef PRODUCT
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Symbol* name= target_method()->name();
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Symbol* signature = target_method()->signature();
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assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
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#endif
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if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
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if (log_develop_is_enabled(Trace, vtables)) {
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ResourceMark rm(THREAD);
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LogTarget(Trace, vtables) lt;
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LogStream ls(lt);
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char* sig = target_method()->name_and_sig_as_C_string();
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ls.print("transitive overriding superclass %s with %s index %d, original flags: ",
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supersuperklass->internal_name(),
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sig, vtable_index);
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super_method->print_linkage_flags(&ls);
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ls.print("overriders flags: ");
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target_method->print_linkage_flags(&ls);
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ls.cr();
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}
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break; // return found superk
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}
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} else {
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// super class has no vtable entry here, stop transitive search
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superk = (InstanceKlass*)NULL;
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break;
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}
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// if no override found yet, continue to search up
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superk = superk->super() == NULL ? NULL : InstanceKlass::cast(superk->super());
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}
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return superk;
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}
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static void log_vtables(int i, bool overrides, const methodHandle& target_method,
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Klass* target_klass, Method* super_method,
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Thread* thread) {
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#ifndef PRODUCT
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if (log_develop_is_enabled(Trace, vtables)) {
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ResourceMark rm(thread);
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LogTarget(Trace, vtables) lt;
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LogStream ls(lt);
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char* sig = target_method()->name_and_sig_as_C_string();
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if (overrides) {
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ls.print("overriding with %s index %d, original flags: ",
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sig, i);
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} else {
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ls.print("NOT overriding with %s index %d, original flags: ",
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sig, i);
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}
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super_method->print_linkage_flags(&ls);
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ls.print("overriders flags: ");
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target_method->print_linkage_flags(&ls);
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ls.cr();
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}
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#endif
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}
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// Update child's copy of super vtable for overrides
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// OR return true if a new vtable entry is required.
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// Only called for InstanceKlass's, i.e. not for arrays
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// If that changed, could not use _klass as handle for klass
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bool klassVtable::update_inherited_vtable(InstanceKlass* klass, const methodHandle& target_method,
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int super_vtable_len, int default_index,
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bool checkconstraints, TRAPS) {
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ResourceMark rm(THREAD);
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bool allocate_new = true;
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assert(klass->is_instance_klass(), "must be InstanceKlass");
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Array<int>* def_vtable_indices = NULL;
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bool is_default = false;
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// default methods are non-private concrete methods in superinterfaces which are added
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// to the vtable with their real method_holder.
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// Since vtable and itable indices share the same storage, don't touch
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// the default method's real vtable/itable index.
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// default_vtable_indices stores the vtable value relative to this inheritor
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if (default_index >= 0 ) {
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is_default = true;
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def_vtable_indices = klass->default_vtable_indices();
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assert(!target_method()->is_private(), "private interface method flagged as default");
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assert(def_vtable_indices != NULL, "def vtable alloc?");
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assert(default_index <= def_vtable_indices->length(), "def vtable len?");
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} else {
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assert(klass == target_method()->method_holder(), "caller resp.");
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// Initialize the method's vtable index to "nonvirtual".
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// If we allocate a vtable entry, we will update it to a non-negative number.
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target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
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}
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// Static and <init> methods are never in
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if (target_method()->is_static() || target_method()->name() == vmSymbols::object_initializer_name()) {
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return false;
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}
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if (target_method->is_final_method(klass->access_flags())) {
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// a final method never needs a new entry; final methods can be statically
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// resolved and they have to be present in the vtable only if they override
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// a super's method, in which case they re-use its entry
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allocate_new = false;
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} else if (klass->is_interface()) {
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allocate_new = false; // see note below in needs_new_vtable_entry
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// An interface never allocates new vtable slots, only inherits old ones.
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// This method will either be assigned its own itable index later,
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// or be assigned an inherited vtable index in the loop below.
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// default methods inherited by classes store their vtable indices
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// in the inheritor's default_vtable_indices.
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// default methods inherited by interfaces may already have a
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// valid itable index, if so, don't change it.
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// Overpass methods in an interface will be assigned an itable index later
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// by an inheriting class.
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// Private interface methods have no itable index and are always invoked nonvirtually,
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// so they retain their nonvirtual_vtable_index value, and therefore can_be_statically_bound()
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// will return true.
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if ((!is_default || !target_method()->has_itable_index()) && !target_method()->is_private()) {
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target_method()->set_vtable_index(Method::pending_itable_index);
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}
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}
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// we need a new entry if there is no superclass
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Klass* super = klass->super();
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if (super == NULL) {
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return allocate_new;
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}
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// private methods in classes always have a new entry in the vtable
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// specification interpretation since classic has
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// private methods not overriding
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// JDK8 adds private methods in interfaces which require invokespecial
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if (target_method()->is_private()) {
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return allocate_new;
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}
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// search through the vtable and update overridden entries
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// Since check_signature_loaders acquires SystemDictionary_lock
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// which can block for gc, once we are in this loop, use handles
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// For classfiles built with >= jdk7, we now look for transitive overrides
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Symbol* name = target_method()->name();
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Symbol* signature = target_method()->signature();
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Klass* target_klass = target_method()->method_holder();
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if (target_klass == NULL) {
|
|
target_klass = _klass;
|
|
}
|
|
|
|
Handle target_loader(THREAD, target_klass->class_loader());
|
|
|
|
Symbol* target_classname = target_klass->name();
|
|
for(int i = 0; i < super_vtable_len; i++) {
|
|
Method* super_method;
|
|
if (is_preinitialized_vtable()) {
|
|
// If this is a shared class, the vtable is already in the final state (fully
|
|
// initialized). Need to look at the super's vtable.
|
|
klassVtable superVtable = super->vtable();
|
|
super_method = superVtable.method_at(i);
|
|
} else {
|
|
super_method = method_at(i);
|
|
}
|
|
// Check if method name matches. Ignore match if klass is an interface and the
|
|
// matching method is a non-public java.lang.Object method. (See JVMS 5.4.3.4)
|
|
// This is safe because the method at this slot should never get invoked.
|
|
// (TBD: put in a method to throw NoSuchMethodError if this slot is ever used.)
|
|
if (super_method->name() == name && super_method->signature() == signature &&
|
|
(!_klass->is_interface() ||
|
|
!SystemDictionary::is_nonpublic_Object_method(super_method))) {
|
|
|
|
// get super_klass for method_holder for the found method
|
|
InstanceKlass* super_klass = super_method->method_holder();
|
|
|
|
// Whether the method is being overridden
|
|
bool overrides = false;
|
|
|
|
// private methods are also never overridden
|
|
if (!super_method->is_private() &&
|
|
(is_default
|
|
|| ((super_klass->is_override(super_method, target_loader, target_classname, THREAD))
|
|
|| ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
|
|
&& ((super_klass = find_transitive_override(super_klass,
|
|
target_method, i, target_loader,
|
|
target_classname, THREAD))
|
|
!= (InstanceKlass*)NULL)))))
|
|
{
|
|
// Package private methods always need a new entry to root their own
|
|
// overriding. They may also override other methods.
|
|
if (!target_method()->is_package_private()) {
|
|
allocate_new = false;
|
|
}
|
|
|
|
// Do not check loader constraints for overpass methods because overpass
|
|
// methods are created by the jvm to throw exceptions.
|
|
if (checkconstraints && !target_method()->is_overpass()) {
|
|
// Override vtable entry if passes loader constraint check
|
|
// if loader constraint checking requested
|
|
// No need to visit his super, since he and his super
|
|
// have already made any needed loader constraints.
|
|
// Since loader constraints are transitive, it is enough
|
|
// to link to the first super, and we get all the others.
|
|
Handle super_loader(THREAD, super_klass->class_loader());
|
|
|
|
if (!oopDesc::equals(target_loader(), super_loader())) {
|
|
ResourceMark rm(THREAD);
|
|
Symbol* failed_type_symbol =
|
|
SystemDictionary::check_signature_loaders(signature, target_loader,
|
|
super_loader, true,
|
|
CHECK_(false));
|
|
if (failed_type_symbol != NULL) {
|
|
stringStream ss;
|
|
ss.print("loader constraint violation for class %s: when selecting "
|
|
"overriding method %s the class loader %s of the "
|
|
"selected method's type %s, and the class loader %s for its super "
|
|
"type %s have different Class objects for the type %s used in the signature (%s; %s)",
|
|
klass->external_name(),
|
|
target_method()->name_and_sig_as_C_string(),
|
|
target_klass->class_loader_data()->loader_name_and_id(),
|
|
target_klass->external_name(),
|
|
super_klass->class_loader_data()->loader_name_and_id(),
|
|
super_klass->external_name(),
|
|
failed_type_symbol->as_klass_external_name(),
|
|
target_klass->class_in_module_of_loader(false, true),
|
|
super_klass->class_in_module_of_loader(false, true));
|
|
THROW_MSG_(vmSymbols::java_lang_LinkageError(), ss.as_string(), false);
|
|
}
|
|
}
|
|
}
|
|
|
|
put_method_at(target_method(), i);
|
|
overrides = true;
|
|
if (!is_default) {
|
|
target_method()->set_vtable_index(i);
|
|
} else {
|
|
if (def_vtable_indices != NULL) {
|
|
if (is_preinitialized_vtable()) {
|
|
// At runtime initialize_vtable is rerun as part of link_class_impl()
|
|
// for a shared class loaded by the non-boot loader.
|
|
// The dumptime vtable index should be the same as the runtime index.
|
|
assert(def_vtable_indices->at(default_index) == i,
|
|
"dump time vtable index is different from runtime index");
|
|
} else {
|
|
def_vtable_indices->at_put(default_index, i);
|
|
}
|
|
}
|
|
assert(super_method->is_default_method() || super_method->is_overpass()
|
|
|| super_method->is_abstract(), "default override error");
|
|
}
|
|
} else {
|
|
overrides = false;
|
|
}
|
|
log_vtables(i, overrides, target_method, target_klass, super_method, THREAD);
|
|
}
|
|
}
|
|
return allocate_new;
|
|
}
|
|
|
|
void klassVtable::put_method_at(Method* m, int index) {
|
|
if (is_preinitialized_vtable()) {
|
|
// At runtime initialize_vtable is rerun as part of link_class_impl()
|
|
// for shared class loaded by the non-boot loader to obtain the loader
|
|
// constraints based on the runtime classloaders' context. The dumptime
|
|
// method at the vtable index should be the same as the runtime method.
|
|
assert(table()[index].method() == m,
|
|
"archived method is different from the runtime method");
|
|
} else {
|
|
if (log_develop_is_enabled(Trace, vtables)) {
|
|
ResourceMark rm;
|
|
LogTarget(Trace, vtables) lt;
|
|
LogStream ls(lt);
|
|
const char* sig = (m != NULL) ? m->name_and_sig_as_C_string() : "<NULL>";
|
|
ls.print("adding %s at index %d, flags: ", sig, index);
|
|
if (m != NULL) {
|
|
m->print_linkage_flags(&ls);
|
|
}
|
|
ls.cr();
|
|
}
|
|
table()[index].set(m);
|
|
}
|
|
}
|
|
|
|
// Find out if a method "m" with superclass "super", loader "classloader" and
|
|
// name "classname" needs a new vtable entry. Let P be a class package defined
|
|
// by "classloader" and "classname".
|
|
// NOTE: The logic used here is very similar to the one used for computing
|
|
// the vtables indices for a method. We cannot directly use that function because,
|
|
// we allocate the InstanceKlass at load time, and that requires that the
|
|
// superclass has been loaded.
|
|
// However, the vtable entries are filled in at link time, and therefore
|
|
// the superclass' vtable may not yet have been filled in.
|
|
bool klassVtable::needs_new_vtable_entry(const methodHandle& target_method,
|
|
const Klass* super,
|
|
Handle classloader,
|
|
Symbol* classname,
|
|
AccessFlags class_flags,
|
|
u2 major_version,
|
|
TRAPS) {
|
|
if (class_flags.is_interface()) {
|
|
// Interfaces do not use vtables, except for java.lang.Object methods,
|
|
// so there is no point to assigning
|
|
// a vtable index to any of their local methods. If we refrain from doing this,
|
|
// we can use Method::_vtable_index to hold the itable index
|
|
return false;
|
|
}
|
|
|
|
if (target_method->is_final_method(class_flags) ||
|
|
// a final method never needs a new entry; final methods can be statically
|
|
// resolved and they have to be present in the vtable only if they override
|
|
// a super's method, in which case they re-use its entry
|
|
(target_method()->is_static()) ||
|
|
// static methods don't need to be in vtable
|
|
(target_method()->name() == vmSymbols::object_initializer_name())
|
|
// <init> is never called dynamically-bound
|
|
) {
|
|
return false;
|
|
}
|
|
|
|
// Concrete interface methods do not need new entries, they override
|
|
// abstract method entries using default inheritance rules
|
|
if (target_method()->method_holder() != NULL &&
|
|
target_method()->method_holder()->is_interface() &&
|
|
!target_method()->is_abstract()) {
|
|
assert(target_method()->is_default_method() || target_method()->is_private(),
|
|
"unexpected interface method type");
|
|
return false;
|
|
}
|
|
|
|
// we need a new entry if there is no superclass
|
|
if (super == NULL) {
|
|
return true;
|
|
}
|
|
|
|
// private methods in classes always have a new entry in the vtable.
|
|
// Specification interpretation since classic has private methods not overriding.
|
|
if (target_method()->is_private()) {
|
|
return true;
|
|
}
|
|
|
|
// Package private methods always need a new entry to root their own
|
|
// overriding. This allows transitive overriding to work.
|
|
if (target_method()->is_package_private()) {
|
|
return true;
|
|
}
|
|
|
|
// search through the super class hierarchy to see if we need
|
|
// a new entry
|
|
ResourceMark rm;
|
|
Symbol* name = target_method()->name();
|
|
Symbol* signature = target_method()->signature();
|
|
const Klass* k = super;
|
|
Method* super_method = NULL;
|
|
InstanceKlass *holder = NULL;
|
|
Method* recheck_method = NULL;
|
|
while (k != NULL) {
|
|
// lookup through the hierarchy for a method with matching name and sign.
|
|
super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
|
|
if (super_method == NULL) {
|
|
break; // we still have to search for a matching miranda method
|
|
}
|
|
// get the class holding the matching method
|
|
// make sure you use that class for is_override
|
|
InstanceKlass* superk = super_method->method_holder();
|
|
// we want only instance method matches
|
|
// pretend private methods are not in the super vtable
|
|
// since we do override around them: e.g. a.m pub/b.m private/c.m pub,
|
|
// ignore private, c.m pub does override a.m pub
|
|
// For classes that were not javac'd together, we also do transitive overriding around
|
|
// methods that have less accessibility
|
|
if ((!super_method->is_static()) &&
|
|
(!super_method->is_private())) {
|
|
if (superk->is_override(super_method, classloader, classname, THREAD)) {
|
|
return false;
|
|
// else keep looking for transitive overrides
|
|
}
|
|
}
|
|
|
|
// Start with lookup result and continue to search up, for versions supporting transitive override
|
|
if (major_version >= VTABLE_TRANSITIVE_OVERRIDE_VERSION) {
|
|
k = superk->super(); // haven't found an override match yet; continue to look
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// if the target method is public or protected it may have a matching
|
|
// miranda method in the super, whose entry it should re-use.
|
|
// Actually, to handle cases that javac would not generate, we need
|
|
// this check for all access permissions.
|
|
const InstanceKlass *sk = InstanceKlass::cast(super);
|
|
if (sk->has_miranda_methods()) {
|
|
if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
|
|
return false; // found a matching miranda; we do not need a new entry
|
|
}
|
|
}
|
|
return true; // found no match; we need a new entry
|
|
}
|
|
|
|
// Support for miranda methods
|
|
|
|
// get the vtable index of a miranda method with matching "name" and "signature"
|
|
int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
|
|
// search from the bottom, might be faster
|
|
for (int i = (length() - 1); i >= 0; i--) {
|
|
Method* m = table()[i].method();
|
|
if (is_miranda_entry_at(i) &&
|
|
m->name() == name && m->signature() == signature) {
|
|
return i;
|
|
}
|
|
}
|
|
return Method::invalid_vtable_index;
|
|
}
|
|
|
|
// check if an entry at an index is miranda
|
|
// requires that method m at entry be declared ("held") by an interface.
|
|
bool klassVtable::is_miranda_entry_at(int i) {
|
|
Method* m = method_at(i);
|
|
Klass* method_holder = m->method_holder();
|
|
InstanceKlass *mhk = InstanceKlass::cast(method_holder);
|
|
|
|
// miranda methods are public abstract instance interface methods in a class's vtable
|
|
if (mhk->is_interface()) {
|
|
assert(m->is_public(), "should be public");
|
|
assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
|
|
if (is_miranda(m, ik()->methods(), ik()->default_methods(), ik()->super(), klass()->is_interface())) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Check if a method is a miranda method, given a class's methods array,
|
|
// its default_method table and its super class.
|
|
// "Miranda" means an abstract non-private method that would not be
|
|
// overridden for the local class.
|
|
// A "miranda" method should only include non-private interface
|
|
// instance methods, i.e. not private methods, not static methods,
|
|
// not default methods (concrete interface methods), not overpass methods.
|
|
// If a given class already has a local (including overpass) method, a
|
|
// default method, or any of its superclasses has the same which would have
|
|
// overridden an abstract method, then this is not a miranda method.
|
|
//
|
|
// Miranda methods are checked multiple times.
|
|
// Pass 1: during class load/class file parsing: before vtable size calculation:
|
|
// include superinterface abstract and default methods (non-private instance).
|
|
// We include potential default methods to give them space in the vtable.
|
|
// During the first run, the current instanceKlass has not yet been
|
|
// created, the superclasses and superinterfaces do have instanceKlasses
|
|
// but may not have vtables, the default_methods list is empty, no overpasses.
|
|
// Default method generation uses the all_mirandas array as the starter set for
|
|
// maximally-specific default method calculation. So, for both classes and
|
|
// interfaces, it is necessary that the first pass will find all non-private
|
|
// interface instance methods, whether or not they are concrete.
|
|
//
|
|
// Pass 2: recalculated during vtable initialization: only include abstract methods.
|
|
// The goal of pass 2 is to walk through the superinterfaces to see if any of
|
|
// the superinterface methods (which were all abstract pre-default methods)
|
|
// need to be added to the vtable.
|
|
// With the addition of default methods, we have three new challenges:
|
|
// overpasses, static interface methods and private interface methods.
|
|
// Static and private interface methods do not get added to the vtable and
|
|
// are not seen by the method resolution process, so we skip those.
|
|
// Overpass methods are already in the vtable, so vtable lookup will
|
|
// find them and we don't need to add a miranda method to the end of
|
|
// the vtable. So we look for overpass methods and if they are found we
|
|
// return false. Note that we inherit our superclasses vtable, so
|
|
// the superclass' search also needs to use find_overpass so that if
|
|
// one is found we return false.
|
|
// False means - we don't need a miranda method added to the vtable.
|
|
//
|
|
// During the second run, default_methods is set up, so concrete methods from
|
|
// superinterfaces with matching names/signatures to default_methods are already
|
|
// in the default_methods list and do not need to be appended to the vtable
|
|
// as mirandas. Abstract methods may already have been handled via
|
|
// overpasses - either local or superclass overpasses, which may be
|
|
// in the vtable already.
|
|
//
|
|
// Pass 3: They are also checked by link resolution and selection,
|
|
// for invocation on a method (not interface method) reference that
|
|
// resolves to a method with an interface as its method_holder.
|
|
// Used as part of walking from the bottom of the vtable to find
|
|
// the vtable index for the miranda method.
|
|
//
|
|
// Part of the Miranda Rights in the US mean that if you do not have
|
|
// an attorney one will be appointed for you.
|
|
bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods,
|
|
Array<Method*>* default_methods, const Klass* super,
|
|
bool is_interface) {
|
|
if (m->is_static() || m->is_private() || m->is_overpass()) {
|
|
return false;
|
|
}
|
|
Symbol* name = m->name();
|
|
Symbol* signature = m->signature();
|
|
|
|
// First look in local methods to see if already covered
|
|
if (InstanceKlass::find_local_method(class_methods, name, signature,
|
|
Klass::find_overpass, Klass::skip_static, Klass::skip_private) != NULL)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// Check local default methods
|
|
if ((default_methods != NULL) &&
|
|
(InstanceKlass::find_method(default_methods, name, signature) != NULL))
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// Iterate on all superclasses, which should be InstanceKlasses.
|
|
// Note that we explicitly look for overpasses at each level.
|
|
// Overpasses may or may not exist for supers for pass 1,
|
|
// they should have been created for pass 2 and later.
|
|
|
|
for (const Klass* cursuper = super; cursuper != NULL; cursuper = cursuper->super())
|
|
{
|
|
Method* found_mth = InstanceKlass::cast(cursuper)->find_local_method(name, signature,
|
|
Klass::find_overpass, Klass::skip_static, Klass::skip_private);
|
|
// Ignore non-public methods in java.lang.Object if klass is an interface.
|
|
if (found_mth != NULL && (!is_interface ||
|
|
!SystemDictionary::is_nonpublic_Object_method(found_mth))) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// Scans current_interface_methods for miranda methods that do not
|
|
// already appear in new_mirandas, or default methods, and are also not defined-and-non-private
|
|
// in super (superclass). These mirandas are added to all_mirandas if it is
|
|
// not null; in addition, those that are not duplicates of miranda methods
|
|
// inherited by super from its interfaces are added to new_mirandas.
|
|
// Thus, new_mirandas will be the set of mirandas that this class introduces,
|
|
// all_mirandas will be the set of all mirandas applicable to this class
|
|
// including all defined in superclasses.
|
|
void klassVtable::add_new_mirandas_to_lists(
|
|
GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
|
|
Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
|
|
Array<Method*>* default_methods, const Klass* super, bool is_interface) {
|
|
|
|
// iterate thru the current interface's method to see if it a miranda
|
|
int num_methods = current_interface_methods->length();
|
|
for (int i = 0; i < num_methods; i++) {
|
|
Method* im = current_interface_methods->at(i);
|
|
bool is_duplicate = false;
|
|
int num_of_current_mirandas = new_mirandas->length();
|
|
// check for duplicate mirandas in different interfaces we implement
|
|
for (int j = 0; j < num_of_current_mirandas; j++) {
|
|
Method* miranda = new_mirandas->at(j);
|
|
if ((im->name() == miranda->name()) &&
|
|
(im->signature() == miranda->signature())) {
|
|
is_duplicate = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
|
|
if (is_miranda(im, class_methods, default_methods, super, is_interface)) { // is it a miranda at all?
|
|
const InstanceKlass *sk = InstanceKlass::cast(super);
|
|
// check if it is a duplicate of a super's miranda
|
|
if (sk->lookup_method_in_all_interfaces(im->name(), im->signature(), Klass::find_defaults) == NULL) {
|
|
new_mirandas->append(im);
|
|
}
|
|
if (all_mirandas != NULL) {
|
|
all_mirandas->append(im);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
|
|
GrowableArray<Method*>* all_mirandas,
|
|
const Klass* super,
|
|
Array<Method*>* class_methods,
|
|
Array<Method*>* default_methods,
|
|
Array<InstanceKlass*>* local_interfaces,
|
|
bool is_interface) {
|
|
assert((new_mirandas->length() == 0) , "current mirandas must be 0");
|
|
|
|
// iterate thru the local interfaces looking for a miranda
|
|
int num_local_ifs = local_interfaces->length();
|
|
for (int i = 0; i < num_local_ifs; i++) {
|
|
InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
|
|
add_new_mirandas_to_lists(new_mirandas, all_mirandas,
|
|
ik->methods(), class_methods,
|
|
default_methods, super, is_interface);
|
|
// iterate thru each local's super interfaces
|
|
Array<InstanceKlass*>* super_ifs = ik->transitive_interfaces();
|
|
int num_super_ifs = super_ifs->length();
|
|
for (int j = 0; j < num_super_ifs; j++) {
|
|
InstanceKlass *sik = super_ifs->at(j);
|
|
add_new_mirandas_to_lists(new_mirandas, all_mirandas,
|
|
sik->methods(), class_methods,
|
|
default_methods, super, is_interface);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Discover miranda methods ("miranda" = "interface abstract, no binding"),
|
|
// and append them into the vtable starting at index initialized,
|
|
// return the new value of initialized.
|
|
// Miranda methods use vtable entries, but do not get assigned a vtable_index
|
|
// The vtable_index is discovered by searching from the end of the vtable
|
|
int klassVtable::fill_in_mirandas(int initialized, TRAPS) {
|
|
ResourceMark rm(THREAD);
|
|
GrowableArray<Method*> mirandas(20);
|
|
get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
|
|
ik()->default_methods(), ik()->local_interfaces(),
|
|
klass()->is_interface());
|
|
for (int i = 0; i < mirandas.length(); i++) {
|
|
if (log_develop_is_enabled(Trace, vtables)) {
|
|
Method* meth = mirandas.at(i);
|
|
LogTarget(Trace, vtables) lt;
|
|
LogStream ls(lt);
|
|
if (meth != NULL) {
|
|
char* sig = meth->name_and_sig_as_C_string();
|
|
ls.print("fill in mirandas with %s index %d, flags: ",
|
|
sig, initialized);
|
|
meth->print_linkage_flags(&ls);
|
|
ls.cr();
|
|
}
|
|
}
|
|
put_method_at(mirandas.at(i), initialized);
|
|
++initialized;
|
|
}
|
|
return initialized;
|
|
}
|
|
|
|
// Copy this class's vtable to the vtable beginning at start.
|
|
// Used to copy superclass vtable to prefix of subclass's vtable.
|
|
void klassVtable::copy_vtable_to(vtableEntry* start) {
|
|
Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
|
|
}
|
|
|
|
#if INCLUDE_JVMTI
|
|
bool klassVtable::adjust_default_method(int vtable_index, Method* old_method, Method* new_method) {
|
|
// If old_method is default, find this vtable index in default_vtable_indices
|
|
// and replace that method in the _default_methods list
|
|
bool updated = false;
|
|
|
|
Array<Method*>* default_methods = ik()->default_methods();
|
|
if (default_methods != NULL) {
|
|
int len = default_methods->length();
|
|
for (int idx = 0; idx < len; idx++) {
|
|
if (vtable_index == ik()->default_vtable_indices()->at(idx)) {
|
|
if (default_methods->at(idx) == old_method) {
|
|
default_methods->at_put(idx, new_method);
|
|
updated = true;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
return updated;
|
|
}
|
|
|
|
// search the vtable for uses of either obsolete or EMCP methods
|
|
void klassVtable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
|
|
int prn_enabled = 0;
|
|
for (int index = 0; index < length(); index++) {
|
|
Method* old_method = unchecked_method_at(index);
|
|
if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
|
|
continue; // skip uninteresting entries
|
|
}
|
|
assert(!old_method->is_deleted(), "vtable methods may not be deleted");
|
|
|
|
Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
|
|
|
|
assert(new_method != NULL, "method_with_idnum() should not be NULL");
|
|
assert(old_method != new_method, "sanity check");
|
|
|
|
put_method_at(new_method, index);
|
|
// For default methods, need to update the _default_methods array
|
|
// which can only have one method entry for a given signature
|
|
bool updated_default = false;
|
|
if (old_method->is_default_method()) {
|
|
updated_default = adjust_default_method(index, old_method, new_method);
|
|
}
|
|
|
|
if (log_is_enabled(Info, redefine, class, update)) {
|
|
ResourceMark rm;
|
|
if (!(*trace_name_printed)) {
|
|
log_info(redefine, class, update)
|
|
("adjust: klassname=%s for methods from name=%s",
|
|
_klass->external_name(), old_method->method_holder()->external_name());
|
|
*trace_name_printed = true;
|
|
}
|
|
log_debug(redefine, class, update, vtables)
|
|
("vtable method update: %s(%s), updated default = %s",
|
|
new_method->name()->as_C_string(), new_method->signature()->as_C_string(), updated_default ? "true" : "false");
|
|
}
|
|
}
|
|
}
|
|
|
|
// a vtable should never contain old or obsolete methods
|
|
bool klassVtable::check_no_old_or_obsolete_entries() {
|
|
for (int i = 0; i < length(); i++) {
|
|
Method* m = unchecked_method_at(i);
|
|
if (m != NULL &&
|
|
(NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void klassVtable::dump_vtable() {
|
|
tty->print_cr("vtable dump --");
|
|
for (int i = 0; i < length(); i++) {
|
|
Method* m = unchecked_method_at(i);
|
|
if (m != NULL) {
|
|
tty->print(" (%5d) ", i);
|
|
m->access_flags().print_on(tty);
|
|
if (m->is_default_method()) {
|
|
tty->print("default ");
|
|
}
|
|
if (m->is_overpass()) {
|
|
tty->print("overpass");
|
|
}
|
|
tty->print(" -- ");
|
|
m->print_name(tty);
|
|
tty->cr();
|
|
}
|
|
}
|
|
}
|
|
#endif // INCLUDE_JVMTI
|
|
|
|
// CDS/RedefineClasses support - clear vtables so they can be reinitialized
|
|
void klassVtable::clear_vtable() {
|
|
for (int i = 0; i < _length; i++) table()[i].clear();
|
|
}
|
|
|
|
bool klassVtable::is_initialized() {
|
|
return _length == 0 || table()[0].method() != NULL;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------------------
|
|
// Itable code
|
|
|
|
// Initialize a itableMethodEntry
|
|
void itableMethodEntry::initialize(Method* m) {
|
|
if (m == NULL) return;
|
|
|
|
#ifdef ASSERT
|
|
if (MetaspaceShared::is_in_shared_metaspace((void*)&_method) &&
|
|
!MetaspaceShared::remapped_readwrite()) {
|
|
// At runtime initialize_itable is rerun as part of link_class_impl()
|
|
// for a shared class loaded by the non-boot loader.
|
|
// The dumptime itable method entry should be the same as the runtime entry.
|
|
assert(_method == m, "sanity");
|
|
}
|
|
#endif
|
|
_method = m;
|
|
}
|
|
|
|
klassItable::klassItable(InstanceKlass* klass) {
|
|
_klass = klass;
|
|
|
|
if (klass->itable_length() > 0) {
|
|
itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
|
|
if (offset_entry != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
|
|
// First offset entry points to the first method_entry
|
|
intptr_t* method_entry = (intptr_t *)(((address)klass) + offset_entry->offset());
|
|
intptr_t* end = klass->end_of_itable();
|
|
|
|
_table_offset = (intptr_t*)offset_entry - (intptr_t*)klass;
|
|
_size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
|
|
_size_method_table = (end - method_entry) / itableMethodEntry::size();
|
|
assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
|
|
return;
|
|
}
|
|
}
|
|
|
|
// The length of the itable was either zero, or it has not yet been initialized.
|
|
_table_offset = 0;
|
|
_size_offset_table = 0;
|
|
_size_method_table = 0;
|
|
}
|
|
|
|
static int initialize_count = 0;
|
|
|
|
// Initialization
|
|
void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
|
|
if (_klass->is_interface()) {
|
|
// This needs to go after vtable indices are assigned but
|
|
// before implementors need to know the number of itable indices.
|
|
assign_itable_indices_for_interface(InstanceKlass::cast(_klass), THREAD);
|
|
}
|
|
|
|
// Cannot be setup doing bootstrapping, interfaces don't have
|
|
// itables, and klass with only ones entry have empty itables
|
|
if (Universe::is_bootstrapping() ||
|
|
_klass->is_interface() ||
|
|
_klass->itable_length() == itableOffsetEntry::size()) return;
|
|
|
|
// There's alway an extra itable entry so we can null-terminate it.
|
|
guarantee(size_offset_table() >= 1, "too small");
|
|
int num_interfaces = size_offset_table() - 1;
|
|
if (num_interfaces > 0) {
|
|
ResourceMark rm(THREAD);
|
|
log_develop_debug(itables)("%3d: Initializing itables for %s", ++initialize_count,
|
|
_klass->name()->as_C_string());
|
|
|
|
|
|
// Iterate through all interfaces
|
|
int i;
|
|
for(i = 0; i < num_interfaces; i++) {
|
|
itableOffsetEntry* ioe = offset_entry(i);
|
|
HandleMark hm(THREAD);
|
|
Klass* interf = ioe->interface_klass();
|
|
assert(interf != NULL && ioe->offset() != 0, "bad offset entry in itable");
|
|
initialize_itable_for_interface(ioe->offset(), InstanceKlass::cast(interf), checkconstraints, CHECK);
|
|
}
|
|
|
|
}
|
|
// Check that the last entry is empty
|
|
itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
|
|
guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
|
|
}
|
|
|
|
|
|
inline bool interface_method_needs_itable_index(Method* m) {
|
|
if (m->is_static()) return false; // e.g., Stream.empty
|
|
if (m->is_initializer()) return false; // <init> or <clinit>
|
|
if (m->is_private()) return false; // uses direct call
|
|
// If an interface redeclares a method from java.lang.Object,
|
|
// it should already have a vtable index, don't touch it.
|
|
// e.g., CharSequence.toString (from initialize_vtable)
|
|
// if (m->has_vtable_index()) return false; // NO!
|
|
return true;
|
|
}
|
|
|
|
int klassItable::assign_itable_indices_for_interface(InstanceKlass* klass, TRAPS) {
|
|
// an interface does not have an itable, but its methods need to be numbered
|
|
ResourceMark rm(THREAD);
|
|
log_develop_debug(itables)("%3d: Initializing itable indices for interface %s",
|
|
++initialize_count, klass->name()->as_C_string());
|
|
Array<Method*>* methods = klass->methods();
|
|
int nof_methods = methods->length();
|
|
int ime_num = 0;
|
|
for (int i = 0; i < nof_methods; i++) {
|
|
Method* m = methods->at(i);
|
|
if (interface_method_needs_itable_index(m)) {
|
|
assert(!m->is_final_method(), "no final interface methods");
|
|
// If m is already assigned a vtable index, do not disturb it.
|
|
if (log_develop_is_enabled(Trace, itables)) {
|
|
LogTarget(Trace, itables) lt;
|
|
LogStream ls(lt);
|
|
assert(m != NULL, "methods can never be null");
|
|
const char* sig = m->name_and_sig_as_C_string();
|
|
if (m->has_vtable_index()) {
|
|
ls.print("vtable index %d for method: %s, flags: ", m->vtable_index(), sig);
|
|
} else {
|
|
ls.print("itable index %d for method: %s, flags: ", ime_num, sig);
|
|
}
|
|
m->print_linkage_flags(&ls);
|
|
ls.cr();
|
|
}
|
|
if (!m->has_vtable_index()) {
|
|
// A shared method could have an initialized itable_index that
|
|
// is < 0.
|
|
assert(m->vtable_index() == Method::pending_itable_index ||
|
|
m->is_shared(),
|
|
"set by initialize_vtable");
|
|
m->set_itable_index(ime_num);
|
|
// Progress to next itable entry
|
|
ime_num++;
|
|
}
|
|
}
|
|
}
|
|
assert(ime_num == method_count_for_interface(klass), "proper sizing");
|
|
return ime_num;
|
|
}
|
|
|
|
int klassItable::method_count_for_interface(InstanceKlass* interf) {
|
|
assert(interf->is_interface(), "must be");
|
|
Array<Method*>* methods = interf->methods();
|
|
int nof_methods = methods->length();
|
|
int length = 0;
|
|
while (nof_methods > 0) {
|
|
Method* m = methods->at(nof_methods-1);
|
|
if (m->has_itable_index()) {
|
|
length = m->itable_index() + 1;
|
|
break;
|
|
}
|
|
nof_methods -= 1;
|
|
}
|
|
#ifdef ASSERT
|
|
int nof_methods_copy = nof_methods;
|
|
while (nof_methods_copy > 0) {
|
|
Method* mm = methods->at(--nof_methods_copy);
|
|
assert(!mm->has_itable_index() || mm->itable_index() < length, "");
|
|
}
|
|
#endif //ASSERT
|
|
// return the rightmost itable index, plus one; or 0 if no methods have
|
|
// itable indices
|
|
return length;
|
|
}
|
|
|
|
|
|
void klassItable::initialize_itable_for_interface(int method_table_offset, InstanceKlass* interf, bool checkconstraints, TRAPS) {
|
|
assert(interf->is_interface(), "must be");
|
|
Array<Method*>* methods = interf->methods();
|
|
int nof_methods = methods->length();
|
|
HandleMark hm;
|
|
Handle interface_loader (THREAD, interf->class_loader());
|
|
|
|
int ime_count = method_count_for_interface(interf);
|
|
for (int i = 0; i < nof_methods; i++) {
|
|
Method* m = methods->at(i);
|
|
methodHandle target;
|
|
if (m->has_itable_index()) {
|
|
// This search must match the runtime resolution, i.e. selection search for invokeinterface
|
|
// to correctly enforce loader constraints for interface method inheritance.
|
|
// Private methods are skipped as a private class method can never be the implementation
|
|
// of an interface method.
|
|
// Invokespecial does not perform selection based on the receiver, so it does not use
|
|
// the cached itable.
|
|
target = LinkResolver::lookup_instance_method_in_klasses(_klass, m->name(), m->signature(),
|
|
Klass::skip_private, CHECK);
|
|
}
|
|
if (target == NULL || !target->is_public() || target->is_abstract() || target->is_overpass()) {
|
|
assert(target == NULL || !target->is_overpass() || target->is_public(),
|
|
"Non-public overpass method!");
|
|
// Entry does not resolve. Leave it empty for AbstractMethodError or other error.
|
|
if (!(target == NULL) && !target->is_public()) {
|
|
// Stuff an IllegalAccessError throwing method in there instead.
|
|
itableOffsetEntry::method_entry(_klass, method_table_offset)[m->itable_index()].
|
|
initialize(Universe::throw_illegal_access_error());
|
|
}
|
|
} else {
|
|
// Entry did resolve, check loader constraints before initializing
|
|
// if checkconstraints requested
|
|
if (checkconstraints) {
|
|
Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
|
|
if (!oopDesc::equals(method_holder_loader(), interface_loader())) {
|
|
ResourceMark rm(THREAD);
|
|
Symbol* failed_type_symbol =
|
|
SystemDictionary::check_signature_loaders(m->signature(),
|
|
method_holder_loader,
|
|
interface_loader,
|
|
true, CHECK);
|
|
if (failed_type_symbol != NULL) {
|
|
stringStream ss;
|
|
ss.print("loader constraint violation in interface itable"
|
|
" initialization for class %s: when selecting method %s the"
|
|
" class loader %s for super interface %s, and the class"
|
|
" loader %s of the selected method's type, %s have"
|
|
" different Class objects for the type %s used in the signature (%s; %s)",
|
|
_klass->external_name(),
|
|
m->name_and_sig_as_C_string(),
|
|
interf->class_loader_data()->loader_name_and_id(),
|
|
interf->external_name(),
|
|
target()->method_holder()->class_loader_data()->loader_name_and_id(),
|
|
target()->method_holder()->external_name(),
|
|
failed_type_symbol->as_klass_external_name(),
|
|
interf->class_in_module_of_loader(false, true),
|
|
target()->method_holder()->class_in_module_of_loader(false, true));
|
|
THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
|
|
}
|
|
}
|
|
}
|
|
|
|
// ime may have moved during GC so recalculate address
|
|
int ime_num = m->itable_index();
|
|
assert(ime_num < ime_count, "oob");
|
|
itableOffsetEntry::method_entry(_klass, method_table_offset)[ime_num].initialize(target());
|
|
if (log_develop_is_enabled(Trace, itables)) {
|
|
ResourceMark rm(THREAD);
|
|
if (target() != NULL) {
|
|
LogTarget(Trace, itables) lt;
|
|
LogStream ls(lt);
|
|
char* sig = target()->name_and_sig_as_C_string();
|
|
ls.print("interface: %s, ime_num: %d, target: %s, method_holder: %s ",
|
|
interf->internal_name(), ime_num, sig,
|
|
target()->method_holder()->internal_name());
|
|
ls.print("target_method flags: ");
|
|
target()->print_linkage_flags(&ls);
|
|
ls.cr();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#if INCLUDE_JVMTI
|
|
// search the itable for uses of either obsolete or EMCP methods
|
|
void klassItable::adjust_method_entries(InstanceKlass* holder, bool * trace_name_printed) {
|
|
|
|
itableMethodEntry* ime = method_entry(0);
|
|
for (int i = 0; i < _size_method_table; i++, ime++) {
|
|
Method* old_method = ime->method();
|
|
if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
|
|
continue; // skip uninteresting entries
|
|
}
|
|
assert(!old_method->is_deleted(), "itable methods may not be deleted");
|
|
|
|
Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
|
|
|
|
assert(new_method != NULL, "method_with_idnum() should not be NULL");
|
|
assert(old_method != new_method, "sanity check");
|
|
|
|
ime->initialize(new_method);
|
|
|
|
if (log_is_enabled(Info, redefine, class, update)) {
|
|
ResourceMark rm;
|
|
if (!(*trace_name_printed)) {
|
|
log_info(redefine, class, update)("adjust: name=%s", old_method->method_holder()->external_name());
|
|
*trace_name_printed = true;
|
|
}
|
|
log_trace(redefine, class, update, itables)
|
|
("itable method update: %s(%s)", new_method->name()->as_C_string(), new_method->signature()->as_C_string());
|
|
}
|
|
}
|
|
}
|
|
|
|
// an itable should never contain old or obsolete methods
|
|
bool klassItable::check_no_old_or_obsolete_entries() {
|
|
itableMethodEntry* ime = method_entry(0);
|
|
for (int i = 0; i < _size_method_table; i++) {
|
|
Method* m = ime->method();
|
|
if (m != NULL &&
|
|
(NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
|
|
return false;
|
|
}
|
|
ime++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void klassItable::dump_itable() {
|
|
itableMethodEntry* ime = method_entry(0);
|
|
tty->print_cr("itable dump --");
|
|
for (int i = 0; i < _size_method_table; i++) {
|
|
Method* m = ime->method();
|
|
if (m != NULL) {
|
|
tty->print(" (%5d) ", i);
|
|
m->access_flags().print_on(tty);
|
|
if (m->is_default_method()) {
|
|
tty->print("default ");
|
|
}
|
|
tty->print(" -- ");
|
|
m->print_name(tty);
|
|
tty->cr();
|
|
}
|
|
ime++;
|
|
}
|
|
}
|
|
#endif // INCLUDE_JVMTI
|
|
|
|
// Setup
|
|
class InterfaceVisiterClosure : public StackObj {
|
|
public:
|
|
virtual void doit(InstanceKlass* intf, int method_count) = 0;
|
|
};
|
|
|
|
// Visit all interfaces with at least one itable method
|
|
void visit_all_interfaces(Array<InstanceKlass*>* transitive_intf, InterfaceVisiterClosure *blk) {
|
|
// Handle array argument
|
|
for(int i = 0; i < transitive_intf->length(); i++) {
|
|
InstanceKlass* intf = transitive_intf->at(i);
|
|
assert(intf->is_interface(), "sanity check");
|
|
|
|
// Find no. of itable methods
|
|
int method_count = 0;
|
|
// method_count = klassItable::method_count_for_interface(intf);
|
|
Array<Method*>* methods = intf->methods();
|
|
if (methods->length() > 0) {
|
|
for (int i = methods->length(); --i >= 0; ) {
|
|
if (interface_method_needs_itable_index(methods->at(i))) {
|
|
method_count++;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Visit all interfaces which either have any methods or can participate in receiver type check.
|
|
// We do not bother to count methods in transitive interfaces, although that would allow us to skip
|
|
// this step in the rare case of a zero-method interface extending another zero-method interface.
|
|
if (method_count > 0 || intf->transitive_interfaces()->length() > 0) {
|
|
blk->doit(intf, method_count);
|
|
}
|
|
}
|
|
}
|
|
|
|
class CountInterfacesClosure : public InterfaceVisiterClosure {
|
|
private:
|
|
int _nof_methods;
|
|
int _nof_interfaces;
|
|
public:
|
|
CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
|
|
|
|
int nof_methods() const { return _nof_methods; }
|
|
int nof_interfaces() const { return _nof_interfaces; }
|
|
|
|
void doit(InstanceKlass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
|
|
};
|
|
|
|
class SetupItableClosure : public InterfaceVisiterClosure {
|
|
private:
|
|
itableOffsetEntry* _offset_entry;
|
|
itableMethodEntry* _method_entry;
|
|
address _klass_begin;
|
|
public:
|
|
SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
|
|
_klass_begin = klass_begin;
|
|
_offset_entry = offset_entry;
|
|
_method_entry = method_entry;
|
|
}
|
|
|
|
itableMethodEntry* method_entry() const { return _method_entry; }
|
|
|
|
void doit(InstanceKlass* intf, int method_count) {
|
|
int offset = ((address)_method_entry) - _klass_begin;
|
|
_offset_entry->initialize(intf, offset);
|
|
_offset_entry++;
|
|
_method_entry += method_count;
|
|
}
|
|
};
|
|
|
|
int klassItable::compute_itable_size(Array<InstanceKlass*>* transitive_interfaces) {
|
|
// Count no of interfaces and total number of interface methods
|
|
CountInterfacesClosure cic;
|
|
visit_all_interfaces(transitive_interfaces, &cic);
|
|
|
|
// There's alway an extra itable entry so we can null-terminate it.
|
|
int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
|
|
|
|
// Statistics
|
|
update_stats(itable_size * wordSize);
|
|
|
|
return itable_size;
|
|
}
|
|
|
|
|
|
// Fill out offset table and interface klasses into the itable space
|
|
void klassItable::setup_itable_offset_table(InstanceKlass* klass) {
|
|
if (klass->itable_length() == 0) return;
|
|
assert(!klass->is_interface(), "Should have zero length itable");
|
|
|
|
// Count no of interfaces and total number of interface methods
|
|
CountInterfacesClosure cic;
|
|
visit_all_interfaces(klass->transitive_interfaces(), &cic);
|
|
int nof_methods = cic.nof_methods();
|
|
int nof_interfaces = cic.nof_interfaces();
|
|
|
|
// Add one extra entry so we can null-terminate the table
|
|
nof_interfaces++;
|
|
|
|
assert(compute_itable_size(klass->transitive_interfaces()) ==
|
|
calc_itable_size(nof_interfaces, nof_methods),
|
|
"mismatch calculation of itable size");
|
|
|
|
// Fill-out offset table
|
|
itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
|
|
itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
|
|
intptr_t* end = klass->end_of_itable();
|
|
assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
|
|
assert((oop*)(end) == (oop*)(ime + nof_methods), "wrong offset calculation (2)");
|
|
|
|
// Visit all interfaces and initialize itable offset table
|
|
SetupItableClosure sic((address)klass, ioe, ime);
|
|
visit_all_interfaces(klass->transitive_interfaces(), &sic);
|
|
|
|
#ifdef ASSERT
|
|
ime = sic.method_entry();
|
|
oop* v = (oop*) klass->end_of_itable();
|
|
assert( (oop*)(ime) == v, "wrong offset calculation (2)");
|
|
#endif
|
|
}
|
|
|
|
|
|
// inverse to itable_index
|
|
Method* klassItable::method_for_itable_index(InstanceKlass* intf, int itable_index) {
|
|
assert(intf->is_interface(), "sanity check");
|
|
assert(intf->verify_itable_index(itable_index), "");
|
|
Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
|
|
|
|
if (itable_index < 0 || itable_index >= method_count_for_interface(intf))
|
|
return NULL; // help caller defend against bad indices
|
|
|
|
int index = itable_index;
|
|
Method* m = methods->at(index);
|
|
int index2 = -1;
|
|
while (!m->has_itable_index() ||
|
|
(index2 = m->itable_index()) != itable_index) {
|
|
assert(index2 < itable_index, "monotonic");
|
|
if (++index == methods->length())
|
|
return NULL;
|
|
m = methods->at(index);
|
|
}
|
|
assert(m->itable_index() == itable_index, "correct inverse");
|
|
|
|
return m;
|
|
}
|
|
|
|
void klassVtable::verify(outputStream* st, bool forced) {
|
|
// make sure table is initialized
|
|
if (!Universe::is_fully_initialized()) return;
|
|
#ifndef PRODUCT
|
|
// avoid redundant verifies
|
|
if (!forced && _verify_count == Universe::verify_count()) return;
|
|
_verify_count = Universe::verify_count();
|
|
#endif
|
|
oop* end_of_obj = (oop*)_klass + _klass->size();
|
|
oop* end_of_vtable = (oop *)&table()[_length];
|
|
if (end_of_vtable > end_of_obj) {
|
|
ResourceMark rm;
|
|
fatal("klass %s: klass object too short (vtable extends beyond end)",
|
|
_klass->internal_name());
|
|
}
|
|
|
|
for (int i = 0; i < _length; i++) table()[i].verify(this, st);
|
|
// verify consistency with superKlass vtable
|
|
Klass* super = _klass->super();
|
|
if (super != NULL) {
|
|
InstanceKlass* sk = InstanceKlass::cast(super);
|
|
klassVtable vt = sk->vtable();
|
|
for (int i = 0; i < vt.length(); i++) {
|
|
verify_against(st, &vt, i);
|
|
}
|
|
}
|
|
}
|
|
|
|
void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
|
|
vtableEntry* vte = &vt->table()[index];
|
|
if (vte->method()->name() != table()[index].method()->name() ||
|
|
vte->method()->signature() != table()[index].method()->signature()) {
|
|
fatal("mismatched name/signature of vtable entries");
|
|
}
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
void klassVtable::print() {
|
|
ResourceMark rm;
|
|
tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
|
|
for (int i = 0; i < length(); i++) {
|
|
table()[i].print();
|
|
tty->cr();
|
|
}
|
|
}
|
|
#endif
|
|
|
|
void vtableEntry::verify(klassVtable* vt, outputStream* st) {
|
|
NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
|
|
Klass* vtklass = vt->klass();
|
|
if (vtklass->is_instance_klass() &&
|
|
(InstanceKlass::cast(vtklass)->major_version() >= klassVtable::VTABLE_TRANSITIVE_OVERRIDE_VERSION)) {
|
|
assert(method() != NULL, "must have set method");
|
|
}
|
|
if (method() != NULL) {
|
|
method()->verify();
|
|
// we sub_type, because it could be a miranda method
|
|
if (!vtklass->is_subtype_of(method()->method_holder())) {
|
|
#ifndef PRODUCT
|
|
print();
|
|
#endif
|
|
fatal("vtableEntry " PTR_FORMAT ": method is from subclass", p2i(this));
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
|
|
void vtableEntry::print() {
|
|
ResourceMark rm;
|
|
tty->print("vtableEntry %s: ", method()->name()->as_C_string());
|
|
if (Verbose) {
|
|
tty->print("m " PTR_FORMAT " ", p2i(method()));
|
|
}
|
|
}
|
|
|
|
class VtableStats : AllStatic {
|
|
public:
|
|
static int no_klasses; // # classes with vtables
|
|
static int no_array_klasses; // # array classes
|
|
static int no_instance_klasses; // # instanceKlasses
|
|
static int sum_of_vtable_len; // total # of vtable entries
|
|
static int sum_of_array_vtable_len; // total # of vtable entries in array klasses only
|
|
static int fixed; // total fixed overhead in bytes
|
|
static int filler; // overhead caused by filler bytes
|
|
static int entries; // total bytes consumed by vtable entries
|
|
static int array_entries; // total bytes consumed by array vtable entries
|
|
|
|
static void do_class(Klass* k) {
|
|
Klass* kl = k;
|
|
klassVtable vt = kl->vtable();
|
|
no_klasses++;
|
|
if (kl->is_instance_klass()) {
|
|
no_instance_klasses++;
|
|
kl->array_klasses_do(do_class);
|
|
}
|
|
if (kl->is_array_klass()) {
|
|
no_array_klasses++;
|
|
sum_of_array_vtable_len += vt.length();
|
|
}
|
|
sum_of_vtable_len += vt.length();
|
|
}
|
|
|
|
static void compute() {
|
|
LockedClassesDo locked_do_class(&do_class);
|
|
ClassLoaderDataGraph::classes_do(&locked_do_class);
|
|
fixed = no_klasses * oopSize; // vtable length
|
|
// filler size is a conservative approximation
|
|
filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
|
|
entries = sizeof(vtableEntry) * sum_of_vtable_len;
|
|
array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
|
|
}
|
|
};
|
|
|
|
int VtableStats::no_klasses = 0;
|
|
int VtableStats::no_array_klasses = 0;
|
|
int VtableStats::no_instance_klasses = 0;
|
|
int VtableStats::sum_of_vtable_len = 0;
|
|
int VtableStats::sum_of_array_vtable_len = 0;
|
|
int VtableStats::fixed = 0;
|
|
int VtableStats::filler = 0;
|
|
int VtableStats::entries = 0;
|
|
int VtableStats::array_entries = 0;
|
|
|
|
void klassVtable::print_statistics() {
|
|
ResourceMark rm;
|
|
HandleMark hm;
|
|
VtableStats::compute();
|
|
tty->print_cr("vtable statistics:");
|
|
tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
|
|
int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
|
|
tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
|
|
tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
|
|
tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
|
|
tty->print_cr("%6d bytes total", total);
|
|
}
|
|
|
|
int klassItable::_total_classes; // Total no. of classes with itables
|
|
long klassItable::_total_size; // Total no. of bytes used for itables
|
|
|
|
void klassItable::print_statistics() {
|
|
tty->print_cr("itable statistics:");
|
|
tty->print_cr("%6d classes with itables", _total_classes);
|
|
tty->print_cr("%6lu K uses for itables (average by class: %ld bytes)", _total_size / K, _total_size / _total_classes);
|
|
}
|
|
|
|
#endif // PRODUCT
|