/*

 * Copyright (c) 1997, 2013, 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.

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 */

#ifndef SHARE_VM_RUNTIME_VM_VERSION_HPP

#define SHARE_VM_RUNTIME_VM_VERSION_HPP

#include "memory/allocation.hpp"

#include "utilities/ostream.hpp"

// VM_Version provides information about the VM.

class Abstract_VM_Version: AllStatic {

 protected:

  friend class VMStructs;

  static const char*  _s_vm_release;

  static const char*  _s_internal_vm_info_string;

  // These are set by machine-dependent initializations

  static bool         _supports_cx8;

  static bool         _supports_atomic_getset4;

  static bool         _supports_atomic_getset8;

  static bool         _supports_atomic_getadd4;

  static bool         _supports_atomic_getadd8;

  static unsigned int _logical_processors_per_package;

  static int          _vm_major_version;

  static int          _vm_minor_version;

  static int          _vm_build_number;

  static bool         _initialized;

  static int          _parallel_worker_threads;

  static bool         _parallel_worker_threads_initialized;

  static int          _reserve_for_allocation_prefetch;

  static unsigned int nof_parallel_worker_threads(unsigned int num,

                                                  unsigned int dem,

                                                  unsigned int switch_pt);

 public:

  static void initialize();

  // Name

  static const char* vm_name();

  // Vendor

  static const char* vm_vendor();

  // VM version information string printed by launcher (java -version)

  static const char* vm_info_string();

  static const char* vm_release();

  static const char* vm_platform_string();

  static const char* vm_build_user();

  static int vm_major_version()               { assert(_initialized, "not initialized"); return _vm_major_version; }

  static int vm_minor_version()               { assert(_initialized, "not initialized"); return _vm_minor_version; }

  static int vm_build_number()                { assert(_initialized, "not initialized"); return _vm_build_number; }

  // Gets the jvm_version_info.jvm_version defined in jvm.h

  static unsigned int jvm_version();

  // Internal version providing additional build information

  static const char* internal_vm_info_string();

  static const char* jre_release_version();

  // does HW support an 8-byte compare-exchange operation?

  static bool supports_cx8()  {

#ifdef SUPPORTS_NATIVE_CX8

    return true;

#else

    return _supports_cx8;

#endif

  }

  // does HW support atomic get-and-set or atomic get-and-add?  Used

  // to guide intrinsification decisions for Unsafe atomic ops

  static bool supports_atomic_getset4()  {return _supports_atomic_getset4;}

  static bool supports_atomic_getset8()  {return _supports_atomic_getset8;}

  static bool supports_atomic_getadd4()  {return _supports_atomic_getadd4;}

  static bool supports_atomic_getadd8()  {return _supports_atomic_getadd8;}

  static unsigned int logical_processors_per_package() {

    return _logical_processors_per_package;

  }

  // Need a space at the end of TLAB for prefetch instructions

  // which may fault when accessing memory outside of heap.

  static int reserve_for_allocation_prefetch() {

    return _reserve_for_allocation_prefetch;

  }

  // ARCH specific policy for the BiasedLocking

  static bool use_biased_locking()  { return true; }

  // Number of page sizes efficiently supported by the hardware.  Most chips now

  // support two sizes, thus this default implementation.  Processor-specific

  // subclasses should define new versions to hide this one as needed.  Note

  // that the O/S may support more sizes, but at most this many are used.

  static uint page_size_count() { return 2; }

  // Returns the number of parallel threads to be used for VM

  // work.  If that number has not been calculated, do so and

  // save it.  Returns ParallelGCThreads if it is set on the

  // command line.

  static unsigned int parallel_worker_threads();

  // Calculates and returns the number of parallel threads.  May

  // be VM version specific.

  static unsigned int calc_parallel_worker_threads();

};

#endif // SHARE_VM_RUNTIME_VM_VERSION_HPP