/*
 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
 *
 * 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 "utilities/copy.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "epsilonCollectedHeap.hpp"
#include "epsilonBarrierSet.hpp"

jint EpsilonCollectedHeap::initialize() {
  size_t max_byte_size = _policy->max_heap_byte_size();

  ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
                                                 _policy->heap_alignment());

  _start = (HeapWord *) heap_rs.base();
  _current = _start;
  _end = (HeapWord *) (heap_rs.base() + heap_rs.size());

  size_t size = pointer_delta(_end, _start);

  initialize_reserved_region(_start, _end);
  os::commit_memory((char*)_start, size*HeapWordSize, _policy->heap_alignment(), false);

  log_info(gc)("Heap space: [" PTR_FORMAT ", " PTR_FORMAT "] (" SIZE_FORMAT "M)",
               p2i(_start), p2i(_end), size*HeapWordSize / M);

  // eagerly zero out everything, or don't bother, let TLAB zeroing do its thing.
//  log_info(gc)("Clearing " SIZE_FORMAT "M", size * HeapWordSize / M);
//  Copy::zero_to_words(_start, size);

  EpsilonBarrierSet* bs = new EpsilonBarrierSet();
  set_barrier_set(bs);

  log_info(gc)("Ready to go. See you at your next OutOfMemoryException.");

  return JNI_OK;
}

HeapWord* EpsilonCollectedHeap::allocate_new_tlab(size_t size) {
  bool trap;
  return mem_allocate(size, &trap);
}

HeapWord* EpsilonCollectedHeap::mem_allocate(size_t size, bool *gc_overhead_limit_was_exceeded) {
  HeapWord* res = _current;
  if (_current + size > _end) {
    log_warning(gc)("Heap is exhausted, you sick bastard. Goodbye.");
    vm_abort(false);
  }
  _current += size;
  *gc_overhead_limit_was_exceeded = false;
  return res;
}