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 * 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 "gc/shared/collectedHeap.hpp"

#include "memory/memRegion.hpp"

#include "oops/oopsHierarchy.hpp"

#include "utilities/exceptions.hpp"

#include "utilities/macros.hpp"

// These fascilities are used for allocating, and initializing newly allocated objects.

class MemAllocator: StackObj {

protected:

  class Allocation;

  CollectedHeap* const _heap;

  Thread* const        _thread;

  Klass* const         _klass;

  const size_t         _word_size;

private:

  // Allocate from the current thread's TLAB, with broken-out slow path.

  HeapWord* allocate_inside_tlab(Allocation& allocation) const;

  HeapWord* allocate_inside_tlab_slow(Allocation& allocation) const;

  HeapWord* allocate_outside_tlab(Allocation& allocation) const;

protected:

  MemAllocator(Klass* klass, size_t word_size, Thread* thread)

    : _heap(Universe::heap()),

      _thread(thread),

      _klass(klass),

      _word_size(word_size)

  { }

  // This function clears the memory of the object

  void mem_clear(HeapWord* mem) const;

  // This finish constructing an oop by installing the mark word and the Klass* pointer

  // last. At the point when the Klass pointer is initialized, this is a constructed object

  // that must be parseable as an oop by concurrent collectors.

  oop finish(HeapWord* mem) const;

  // Raw memory allocation. This may or may not use TLAB allocations to satisfy the

  // allocation. A GC implementation may override this function to satisfy the allocation

  // in any way. But the default is to try a TLAB allocation, and otherwise perform

  // mem_allocate.

  virtual HeapWord* mem_allocate(Allocation& allocation) const;

  virtual MemRegion obj_memory_range(oop obj) const {

    return MemRegion((HeapWord*)obj, _word_size);

  }

public:

  oop allocate() const;

  virtual oop initialize(HeapWord* mem) const = 0;

};

class ObjAllocator: public MemAllocator {

public:

  ObjAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())

    : MemAllocator(klass, word_size, thread) {}

  virtual oop initialize(HeapWord* mem) const;

};

class ObjArrayAllocator: public MemAllocator {

  const int  _length;

  const bool _do_zero;

protected:

  virtual MemRegion obj_memory_range(oop obj) const;

public:

  ObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero,

                    Thread* thread = Thread::current())

    : MemAllocator(klass, word_size, thread),

      _length(length),

      _do_zero(do_zero) {}

  virtual oop initialize(HeapWord* mem) const;

};

class ClassAllocator: public MemAllocator {

public:

  ClassAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())

    : MemAllocator(klass, word_size, thread) {}

  virtual oop initialize(HeapWord* mem) const;

};