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 * Copyright (c) 2014, Red Hat Inc. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef CPU_AARCH64_JAVAFRAMEANCHOR_AARCH64_HPP
#define CPU_AARCH64_JAVAFRAMEANCHOR_AARCH64_HPP

private:

  // FP value associated with _last_Java_sp:
  intptr_t* volatile        _last_Java_fp;           // pointer is volatile not what it points to

public:
  // Each arch must define reset, save, restore
  // These are used by objects that only care about:
  //  1 - initializing a new state (thread creation, javaCalls)
  //  2 - saving a current state (javaCalls)
  //  3 - restoring an old state (javaCalls)

  void clear(void) {
    // No hardware barriers are necessary. All members are volatile and the profiler
    // is run from a signal handler and only observers the thread its running on.

    // clearing _last_Java_sp must be first
    _last_Java_sp = nullptr;
    _last_Java_fp = nullptr;
    _last_Java_pc = nullptr;
  }

  void copy(JavaFrameAnchor* src) {
    // No hardware barriers are necessary. All members are volatile and the profiler
    // is run from a signal handler and only observers the thread its running on.

    // We must clear _last_Java_sp before copying the rest of the new data
    if (_last_Java_sp != src->_last_Java_sp) {
      _last_Java_sp = nullptr;
    }
    _last_Java_fp = src->_last_Java_fp;
    _last_Java_pc = src->_last_Java_pc;
    // Must be last so profiler will always see valid frame if has_last_frame() is true
    _last_Java_sp = src->_last_Java_sp;
  }

  bool walkable(void)                            { return _last_Java_sp != nullptr && _last_Java_pc != nullptr; }

  void make_walkable();

  intptr_t* last_Java_sp(void) const             { return _last_Java_sp; }

  address last_Java_pc(void)                     { return _last_Java_pc; }

private:

  static ByteSize last_Java_fp_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_fp); }

public:

  void set_last_Java_sp(intptr_t* sp)            { _last_Java_sp = sp; OrderAccess::release(); }

  intptr_t*   last_Java_fp(void)                 { return _last_Java_fp; }

  void set_last_Java_fp(intptr_t* fp)            { _last_Java_fp = fp; }

#endif // CPU_AARCH64_JAVAFRAMEANCHOR_AARCH64_HPP