/*

 * Copyright (c) 2015, 2018, 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

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 */

#include "precompiled.hpp"

#include "gc/g1/g1OopClosures.inline.hpp"

#include "gc/g1/g1RootClosures.hpp"

#include "gc/g1/g1SharedClosures.hpp"

// Closures used for standard G1 evacuation.

class G1EvacuationClosures : public G1EvacuationRootClosures {

  G1SharedClosures<G1MarkNone> _closures;

public:

  G1EvacuationClosures(G1CollectedHeap* g1h,

                       G1ParScanThreadState* pss,

                       bool in_young_gc) :

      _closures(g1h, pss, in_young_gc, /* cld_claim */ ClassLoaderData::_claim_none) {}

  OopClosure* weak_oops()   { return &_closures._oops; }

  OopClosure* strong_oops() { return &_closures._oops; }

  CLDClosure* weak_clds()             { return &_closures._clds; }

  CLDClosure* strong_clds()           { return &_closures._clds; }

  CLDClosure* second_pass_weak_clds() { return NULL; }

  CodeBlobClosure* strong_codeblobs()      { return &_closures._codeblobs; }

  CodeBlobClosure* weak_codeblobs()        { return &_closures._codeblobs; }

  bool trace_metadata()         { return false; }

};

// Closures used during initial mark.

// The treatment of "weak" roots is selectable through the template parameter,

// this is usually used to control unloading of classes and interned strings.

template <G1Mark MarkWeak>

class G1InitialMarkClosures : public G1EvacuationRootClosures {

  G1SharedClosures<G1MarkFromRoot> _strong;

  G1SharedClosures<MarkWeak>       _weak;

  // Filter method to help with returning the appropriate closures

  // depending on the class template parameter.

  template <G1Mark Mark, typename T>

  T* null_if(T* t) {

    if (Mark == MarkWeak) {

      return NULL;

    }

    return t;

  }

public:

  G1InitialMarkClosures(G1CollectedHeap* g1h,

                        G1ParScanThreadState* pss) :

      _strong(g1h, pss, /* process_only_dirty_klasses */ false, /* cld_claim */ ClassLoaderData::_claim_strong),

      _weak(g1h, pss,   /* process_only_dirty_klasses */ false, /* cld_claim */ ClassLoaderData::_claim_strong) {}

  OopClosure* weak_oops()   { return &_weak._oops; }

  OopClosure* strong_oops() { return &_strong._oops; }

  // If MarkWeak is G1MarkPromotedFromRoot then the weak CLDs must be processed in a second pass.

  CLDClosure* weak_clds()             { return null_if<G1MarkPromotedFromRoot>(&_weak._clds); }

  CLDClosure* strong_clds()           { return &_strong._clds; }

  // If MarkWeak is G1MarkFromRoot then all CLDs are processed by the weak and strong variants

  // return a NULL closure for the following specialized versions in that case.

  CLDClosure* second_pass_weak_clds() { return null_if<G1MarkFromRoot>(&_weak._clds); }

  CodeBlobClosure* strong_codeblobs()      { return &_strong._codeblobs; }

  CodeBlobClosure* weak_codeblobs()        { return &_weak._codeblobs; }

  // If we are not marking all weak roots then we are tracing

  // which metadata is alive.

  bool trace_metadata()         { return MarkWeak == G1MarkPromotedFromRoot; }

};

G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1ParScanThreadState* pss, G1CollectedHeap* g1h) {

  G1EvacuationRootClosures* res = NULL;

  if (g1h->collector_state()->in_initial_mark_gc()) {

    if (ClassUnloadingWithConcurrentMark) {

      res = new G1InitialMarkClosures<G1MarkPromotedFromRoot>(g1h, pss);

    } else {

      res = new G1InitialMarkClosures<G1MarkFromRoot>(g1h, pss);

    }

  } else {

    res = new G1EvacuationClosures(g1h, pss, g1h->collector_state()->in_young_only_phase());

  }

  return res;

}