text: /*
   * 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.
   *
   */
  
  #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
  