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/*
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#ifndef SHARE_CDS_CLASSPRELINKER_HPP
#define SHARE_CDS_CLASSPRELINKER_HPP
#include "oops/oopsHierarchy.hpp"
#include "memory/allStatic.hpp"
#include "memory/allocation.hpp"
#include "runtime/handles.hpp"
#include "utilities/exceptions.hpp"
#include "utilities/macros.hpp"
#include "utilities/resourceHash.hpp"
class ConstantPool;
class constantPoolHandle;
class InstanceKlass;
class Klass;
// ClassPrelinker is used to perform ahead-of-time linking of ConstantPool entries
// for archived InstanceKlasses.
//
// At run time, Java classes are loaded dynamically and may be replaced with JVMTI.
// Therefore, we take care to prelink only the ConstantPool entries that are
// guatanteed to resolve to the same results at both dump time and run time.
//
// For example, a JVM_CONSTANT_Class reference to a supertype can be safely resolved
// at dump time, because at run time we will load a class from the CDS archive only
// if all of its supertypes are loaded from the CDS archive.
class ClassPrelinker : AllStatic {
using ClassesTable = ResourceHashtable<InstanceKlass*, bool, 15889, AnyObj::C_HEAP, mtClassShared> ;
static ClassesTable* _processed_classes;
static ClassesTable* _vm_classes;
static void add_one_vm_class(InstanceKlass* ik);
#ifdef ASSERT
static bool is_in_archivebuilder_buffer(address p);
#endif
template <typename T>
static bool is_in_archivebuilder_buffer(T p) {
return is_in_archivebuilder_buffer((address)(p));
}
static void resolve_string(constantPoolHandle cp, int cp_index, TRAPS) NOT_CDS_JAVA_HEAP_RETURN;
static Klass* maybe_resolve_class(constantPoolHandle cp, int cp_index, TRAPS);
static bool can_archive_resolved_klass(InstanceKlass* cp_holder, Klass* resolved_klass);
static Klass* find_loaded_class(JavaThread* THREAD, oop class_loader, Symbol* name);
public:
static void initialize();
static void dispose();
// Is this class resolved as part of vmClasses::resolve_all()? If so, these
// classes are guatanteed to be loaded at runtime (and cannot be replaced by JVMTI)
// when CDS is enabled. Therefore, we can safely keep a direct reference to these
// classes.
static bool is_vm_class(InstanceKlass* ik);
// Resolve all constant pool entries that are safe to be stored in the
// CDS archive.
static void dumptime_resolve_constants(InstanceKlass* ik, TRAPS);
// Can we resolve the klass entry at cp_index in this constant pool, and store
// the result in the CDS archive? Returns true if cp_index is guaranteed to
// resolve to the same InstanceKlass* at both dump time and run time.
static bool can_archive_resolved_klass(ConstantPool* cp, int cp_index);
};
#endif // SHARE_CDS_CLASSPRELINKER_HPP
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