src/hotspot/share/jfr/leakprofiler/chains/rootSetClosure.cpp

/*
 * Copyright (c) 2014, 2025, 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.
 *
 */

#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/stringTable.hpp"
#include "gc/shared/oopStorage.inline.hpp"
#include "gc/shared/oopStorageSet.inline.hpp"
#include "gc/shared/strongRootsScope.hpp"
#include "jfr/leakprofiler/chains/bfsClosure.hpp"
#include "jfr/leakprofiler/chains/dfsClosure.hpp"
#include "jfr/leakprofiler/chains/edgeQueue.hpp"
#include "jfr/leakprofiler/chains/rootSetClosure.hpp"
#include "jfr/leakprofiler/utilities/unifiedOopRef.inline.hpp"
#include "oops/access.inline.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/threads.hpp"
#include "services/management.hpp"
#include "utilities/align.hpp"

template <typename Delegate>
RootSetClosure<Delegate>::RootSetClosure(Delegate* delegate) : _delegate(delegate) {}

template <typename Delegate>
void RootSetClosure<Delegate>::do_oop(oop* ref) {
  assert(ref != nullptr, "invariant");
  assert(is_aligned(ref, HeapWordSize), "invariant");
  if (NativeAccess<>::oop_load(ref) != nullptr) {
    _delegate->do_root(UnifiedOopRef::encode_in_native(ref));
  }
}

template <typename Delegate>
void RootSetClosure<Delegate>::do_oop(narrowOop* ref) {
  assert(ref != nullptr, "invariant");
  assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
  if (!CompressedOops::is_null(*ref)) {
    _delegate->do_root(UnifiedOopRef::encode_in_native(ref));
  }
}

class RootSetClosureMarkScope : public MarkScope {};

template <typename Delegate>
class RawRootClosure : public OopClosure {
  Delegate* _delegate;

public:
  RawRootClosure(Delegate* delegate) : _delegate(delegate) {}

  void do_oop(oop* ref) {
    assert(ref != nullptr, "invariant");
    assert(is_aligned(ref, HeapWordSize), "invariant");
    if (*ref != nullptr) {
      _delegate->do_root(UnifiedOopRef::encode_as_raw(ref));
    }
  }

  void do_oop(narrowOop* ref) {
    assert(ref != nullptr, "invariant");
    assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
    if (!CompressedOops::is_null(*ref)) {
      _delegate->do_root(UnifiedOopRef::encode_as_raw(ref));
    }
  }
};

template <typename Delegate>
void RootSetClosure<Delegate>::process() {
  RootSetClosureMarkScope mark_scope;

  CLDToOopClosure cldt_closure(this, ClassLoaderData::_claim_none);
  ClassLoaderDataGraph::always_strong_cld_do(&cldt_closure);

  OopStorageSet::strong_oops_do(this);

  // We don't follow code blob oops, because they have misaligned oops.
  RawRootClosure<Delegate> rrc(_delegate);
  Threads::oops_do(&rrc, nullptr);
}

template class RootSetClosure<BFSClosure>;
template class RootSetClosure<DFSClosure>;