/*

 * Copyright (c) 2014, 2019, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_JFR_UTILITIES_JFRALLOCATION_HPP

#define SHARE_JFR_UTILITIES_JFRALLOCATION_HPP

#include "memory/allocation.hpp"

#include "services/memTracker.hpp"

#include "utilities/exceptions.hpp"

/*

 * A subclass to the CHeapObj<mtTracing> allocator, useful for critical

 * Jfr subsystems. Critical in this context means subsystems for which

 * allocations are crucial to the bootstrap and initialization of Jfr.

 * The default behaviour by a CHeapObj is to call vm_exit_out_of_memory()

 * on allocation failure and this is problematic in combination with the

 * Jfr on-demand, dynamic start at runtime, capability.

 * We would not like a user dynamically starting Jfr to

 * tear down the VM she is about to inspect as a side effect.

 *

 * This allocator uses the RETURN_NULL capabilities

 * instead of calling vm_exit_out_of_memory() until Jfr is properly started.

 * This allows for controlled behaviour on allocation failures during startup,

 * which means we can take actions on failure, such as transactional rollback

 * (deallocations and restorations).

 * In addition, this allocator allows for easy hooking of memory

 * allocations / deallocations for debugging purposes.

 */

class JfrCHeapObj : public CHeapObj<mtTracing> {

 private:

  static void on_memory_allocation(const void* allocation, size_t size);

  static char* allocate_array_noinline(size_t elements, size_t element_size);

 public:

  NOINLINE void* operator new(size_t size) throw();

  NOINLINE void* operator new (size_t size, const std::nothrow_t&  nothrow_constant) throw();

  NOINLINE void* operator new [](size_t size) throw();

  NOINLINE void* operator new [](size_t size, const std::nothrow_t&  nothrow_constant) throw();

  void  operator delete(void* p, size_t size);

  void  operator delete [] (void* p, size_t size);

  static char* realloc_array(char* old, size_t size);

  static void free(void* p, size_t size = 0);

  template <class T>

  static T* new_array(size_t size) {

    T* const memory = (T*)allocate_array_noinline(size, sizeof(T));

    on_memory_allocation(memory, sizeof(T) * size);

    return memory;

  }

};

#endif // SHARE_JFR_UTILITIES_JFRALLOCATION_HPP