/*

 * Copyright (c) 2001, 2015, 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 "oops/oop.inline.hpp"

#include "runtime/atomic.inline.hpp"

// This version requires locking.

inline HeapWord* G1OffsetTableContigSpace::allocate_impl(size_t size,

                                                HeapWord* const end_value) {

  HeapWord* obj = top();

  if (pointer_delta(end_value, obj) >= size) {

    HeapWord* new_top = obj + size;

    set_top(new_top);

    assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

    return obj;

  } else {

    return NULL;

  }

}

// This version is lock-free.

inline HeapWord* G1OffsetTableContigSpace::par_allocate_impl(size_t size,

                                                    HeapWord* const end_value) {

  do {

    HeapWord* obj = top();

    if (pointer_delta(end_value, obj) >= size) {

      HeapWord* new_top = obj + size;

      HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);

      // result can be one of two:

      //  the old top value: the exchange succeeded

      //  otherwise: the new value of the top is returned.

      if (result == obj) {

        assert(is_aligned(obj) && is_aligned(new_top), "checking alignment");

        return obj;

      }

    } else {

      return NULL;

    }

  } while (true);

}

inline HeapWord* G1OffsetTableContigSpace::allocate(size_t size) {

  HeapWord* res = allocate_impl(size, end());

  if (res != NULL) {

    _offsets.alloc_block(res, size);

  }

  return res;

}

// Because of the requirement of keeping "_offsets" up to date with the

// allocations, we sequentialize these with a lock.  Therefore, best if

// this is used for larger LAB allocations only.

inline HeapWord* G1OffsetTableContigSpace::par_allocate(size_t size) {

  MutexLocker x(&_par_alloc_lock);

  return allocate(size);

}

inline HeapWord* G1OffsetTableContigSpace::block_start(const void* p) {

  return _offsets.block_start(p);

}

inline HeapWord*

G1OffsetTableContigSpace::block_start_const(const void* p) const {

  return _offsets.block_start_const(p);

}

inline bool

HeapRegion::block_is_obj(const HeapWord* p) const {

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  if (ClassUnloadingWithConcurrentMark) {

    return !g1h->is_obj_dead(oop(p), this);

  }

  return p < top();

}

inline size_t

HeapRegion::block_size(const HeapWord *addr) const {

  if (addr == top()) {

    return pointer_delta(end(), addr);

  }

  if (block_is_obj(addr)) {

    return oop(addr)->size();

  }

  assert(ClassUnloadingWithConcurrentMark,

      err_msg("All blocks should be objects if G1 Class Unloading isn't used. "

              "HR: ["PTR_FORMAT", "PTR_FORMAT", "PTR_FORMAT") "

              "addr: " PTR_FORMAT,

              p2i(bottom()), p2i(top()), p2i(end()), p2i(addr)));

  // Old regions' dead objects may have dead classes

  // We need to find the next live object in some other

  // manner than getting the oop size

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  HeapWord* next = g1h->concurrent_mark()->prevMarkBitMap()->

      getNextMarkedWordAddress(addr, prev_top_at_mark_start());

  assert(next > addr, "must get the next live object");

  return pointer_delta(next, addr);

}

inline HeapWord* HeapRegion::par_allocate_no_bot_updates(size_t word_size) {

  assert(is_young(), "we can only skip BOT updates on young regions");

  return par_allocate_impl(word_size, end());

}

inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t word_size) {

  assert(is_young(), "we can only skip BOT updates on young regions");

  return allocate_impl(word_size, end());

}

inline void HeapRegion::note_start_of_marking() {

  _next_marked_bytes = 0;

  _next_top_at_mark_start = top();

}

inline void HeapRegion::note_end_of_marking() {

  _prev_top_at_mark_start = _next_top_at_mark_start;

  _prev_marked_bytes = _next_marked_bytes;

  _next_marked_bytes = 0;

  assert(_prev_marked_bytes <=

         (size_t) pointer_delta(prev_top_at_mark_start(), bottom()) *

         HeapWordSize, "invariant");

}

inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {

  if (is_survivor()) {

    // This is how we always allocate survivors.

    assert(_next_top_at_mark_start == bottom(), "invariant");

  } else {

    if (during_initial_mark) {

      // During initial-mark we'll explicitly mark any objects on old

      // regions that are pointed to by roots. Given that explicit

      // marks only make sense under NTAMS it'd be nice if we could

      // check that condition if we wanted to. Given that we don't

      // know where the top of this region will end up, we simply set

      // NTAMS to the end of the region so all marks will be below

      // NTAMS. We'll set it to the actual top when we retire this region.

      _next_top_at_mark_start = end();

    } else {

      // We could have re-used this old region as to-space over a

      // couple of GCs since the start of the concurrent marking

      // cycle. This means that [bottom,NTAMS) will contain objects

      // copied up to and including initial-mark and [NTAMS, top)

      // will contain objects copied during the concurrent marking cycle.

      assert(top() >= _next_top_at_mark_start, "invariant");

    }

  }

}

inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {

  if (is_survivor()) {

    // This is how we always allocate survivors.

    assert(_next_top_at_mark_start == bottom(), "invariant");

  } else {

    if (during_initial_mark) {

      // See the comment for note_start_of_copying() for the details

      // on this.

      assert(_next_top_at_mark_start == end(), "pre-condition");

      _next_top_at_mark_start = top();

    } else {

      // See the comment for note_start_of_copying() for the details

      // on this.

      assert(top() >= _next_top_at_mark_start, "invariant");

    }

  }

}

inline bool HeapRegion::in_collection_set() const {

  return G1CollectedHeap::heap()->is_in_cset(this);

}