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>
/*
* Copyright (c) 2011, 2012, 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).
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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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*/
#ifndef SHARE_VM_OOPS_METADATA_HPP
#define SHARE_VM_OOPS_METADATA_HPP
#include "utilities/exceptions.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/ostream.hpp"
// This is the base class for an internal Class related metadata
class Metadata : public MetaspaceObj {
// Debugging hook to check that the metadata has not been deleted.
NOT_PRODUCT(int _valid;)
public:
NOT_PRODUCT(Metadata() { _valid = 0; })
NOT_PRODUCT(bool is_valid() const volatile { return _valid == 0; })
int identity_hash() { return (int)(uintptr_t)this; }
// Rehashing support for tables containing pointers to this
unsigned int new_hash(jint seed) { ShouldNotReachHere(); return 0; }
virtual bool is_klass() const volatile { return false; }
virtual bool is_method() const volatile { return false; }
virtual bool is_methodData() const volatile { return false; }
virtual bool is_constantPool() const volatile { return false; }
virtual const char* internal_name() const = 0;
void print() const { print_on(tty); }
void print_value() const { print_value_on(tty); }
void print_maybe_null() const { print_on_maybe_null(tty); }
void print_on_maybe_null(outputStream* st) const {
if (this == NULL)
st->print("NULL");
else
print_on(tty);
}
void print_value_on_maybe_null(outputStream* st) const {
if (this == NULL)
st->print("NULL");
else
print_value_on(tty);
}
virtual void print_on(outputStream* st) const; // First level print
virtual void print_value_on(outputStream* st) const = 0; // Second level print
char* print_value_string() const;
// Used to keep metadata alive during class redefinition
// Can't assert because is called for delete functions (as an assert)
virtual bool on_stack() const { return false; }
virtual void set_on_stack(const bool value);
// Set on_stack bit, so that the metadata is not cleared
// during class redefinition. This is a virtual call because only methods
// and constant pools need to be set, but someday instanceKlasses might also.
static void mark_on_stack(Metadata* m) { m->set_on_stack(true); }
};
#endif // SHARE_VM_OOPS_METADATA_HPP