/*

 * Copyright (c) 2002, 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).

 *

 * 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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 */

#ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP

#define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP

#include "gc_implementation/parallelScavenge/cardTableExtension.hpp"

#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

#include "gc_implementation/parallelScavenge/psPromotionManager.hpp"

#include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"

#include "gc_implementation/parallelScavenge/psScavenge.hpp"

#include "memory/iterator.hpp"

inline void PSScavenge::save_to_space_top_before_gc() {

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  _to_space_top_before_gc = heap->young_gen()->to_space()->top();

}

template <class T> inline bool PSScavenge::should_scavenge(T* p) {

  T heap_oop = oopDesc::load_heap_oop(p);

  return PSScavenge::is_obj_in_young(heap_oop);

}

template <class T>

inline bool PSScavenge::should_scavenge(T* p, MutableSpace* to_space) {

  if (should_scavenge(p)) {

    oop obj = oopDesc::load_decode_heap_oop_not_null(p);

    // Skip objects copied to to_space since the scavenge started.

    HeapWord* const addr = (HeapWord*)obj;

    return addr < to_space_top_before_gc() || addr >= to_space->end();

  }

  return false;

}

template <class T>

inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {

  if (check_to_space) {

    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

    return should_scavenge(p, heap->young_gen()->to_space());

  }

  return should_scavenge(p);

}

// Attempt to "claim" oop at p via CAS, push the new obj if successful

// This version tests the oop* to make sure it is within the heap before

// attempting marking.

template <class T, bool promote_immediately>

inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,

                                                   T*                  p) {

  assert(should_scavenge(p, true), "revisiting object?");

  oop o = oopDesc::load_decode_heap_oop_not_null(p);

  oop new_obj = o->is_forwarded()

        ? o->forwardee()

        : pm->copy_to_survivor_space<promote_immediately>(o);

#ifndef PRODUCT

  // This code must come after the CAS test, or it will print incorrect

  // information.

  if (TraceScavenge &&  o->is_forwarded()) {

    gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (%d)}",

       "forwarding",

       new_obj->klass()->internal_name(), o, new_obj, new_obj->size());

  }

#endif

  oopDesc::encode_store_heap_oop_not_null(p, new_obj);

  // We cannot mark without test, as some code passes us pointers

  // that are outside the heap. These pointers are either from roots

  // or from metadata.

  if ((!PSScavenge::is_obj_in_young((HeapWord*)p)) &&

      Universe::heap()->is_in_reserved(p)) {

    if (PSScavenge::is_obj_in_young(new_obj)) {

      card_table()->inline_write_ref_field_gc(p, new_obj);

    }

  }

}

template<bool promote_immediately>

class PSRootsClosure: public OopClosure {

 private:

  PSPromotionManager* _promotion_manager;

 protected:

  template <class T> void do_oop_work(T *p) {

    if (PSScavenge::should_scavenge(p)) {

      // We never card mark roots, maybe call a func without test?

      PSScavenge::copy_and_push_safe_barrier<T, promote_immediately>(_promotion_manager, p);

    }

  }

 public:

  PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }

  void do_oop(oop* p)       { PSRootsClosure::do_oop_work(p); }

  void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }

};

typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;

typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;

// Scavenges a single oop in a Klass.

class PSScavengeFromKlassClosure: public OopClosure {

 private:

  PSPromotionManager* _pm;

  // Used to redirty a scanned klass if it has oops

  // pointing to the young generation after being scanned.

  Klass*             _scanned_klass;

 public:

  PSScavengeFromKlassClosure(PSPromotionManager* pm) : _pm(pm), _scanned_klass(NULL) { }

  void do_oop(narrowOop* p) { ShouldNotReachHere(); }

  void do_oop(oop* p)       {

    ParallelScavengeHeap* psh = ParallelScavengeHeap::heap();

    assert(!psh->is_in_reserved(p), "GC barrier needed");

    if (PSScavenge::should_scavenge(p)) {

      assert(!Universe::heap()->is_in_reserved(p), "Not from meta-data?");

      assert(PSScavenge::should_scavenge(p, true), "revisiting object?");

      oop o = *p;

      oop new_obj;

      if (o->is_forwarded()) {

        new_obj = o->forwardee();

      } else {

        new_obj = _pm->copy_to_survivor_space</*promote_immediately=*/false>(o);

      }

      oopDesc::encode_store_heap_oop_not_null(p, new_obj);

      if (PSScavenge::is_obj_in_young(new_obj)) {

        do_klass_barrier();

      }

    }

  }

  void set_scanned_klass(Klass* klass) {

    assert(_scanned_klass == NULL || klass == NULL, "Should always only handling one klass at a time");

    _scanned_klass = klass;

  }

 private:

  void do_klass_barrier() {

    assert(_scanned_klass != NULL, "Should not be called without having a scanned klass");

    _scanned_klass->record_modified_oops();

  }

};

// Scavenges the oop in a Klass.

class PSScavengeKlassClosure: public KlassClosure {

 private:

  PSScavengeFromKlassClosure _oop_closure;

 protected:

 public:

  PSScavengeKlassClosure(PSPromotionManager* pm) : _oop_closure(pm) { }

  void do_klass(Klass* klass) {

    // If the klass has not been dirtied we know that there's

    // no references into  the young gen and we can skip it.

#ifndef PRODUCT

    if (TraceScavenge) {

      ResourceMark rm;

      gclog_or_tty->print_cr("PSScavengeKlassClosure::do_klass %p, %s, dirty: %s",

                             klass,

                             klass->external_name(),

                             klass->has_modified_oops() ? "true" : "false");

    }

#endif

    if (klass->has_modified_oops()) {

      // Clean the klass since we're going to scavenge all the metadata.

      klass->clear_modified_oops();

      // Setup the promotion manager to redirty this klass

      // if references are left in the young gen.

      _oop_closure.set_scanned_klass(klass);

      klass->oops_do(&_oop_closure);

      _oop_closure.set_scanned_klass(NULL);

    }

  }

};

#endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP