/*

 * Copyright (c) 2002, 2018, 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_JAVAFRAMEANCHOR_HPP

#define SHARE_VM_RUNTIME_JAVAFRAMEANCHOR_HPP

#include "runtime/orderAccess.hpp"

#include "utilities/globalDefinitions.hpp"

#include "utilities/macros.hpp"

//

// An object for encapsulating the machine/os dependent part of a JavaThread frame state

//

class JavaThread;

class MacroAssembler;

class JavaFrameAnchor {

// Too many friends...

friend class CallNativeDirectNode;

friend class OptoRuntime;

friend class Runtime1;

friend class StubAssembler;

friend class CallRuntimeDirectNode;

friend class MacroAssembler;

friend class LIR_Assembler;

friend class GraphKit;

friend class StubGenerator;

friend class JavaThread;

friend class frame;

friend class VMStructs;

friend class JVMCIVMStructs;

friend class BytecodeInterpreter;

friend class JavaCallWrapper;

 private:

  //

  // Whenever _last_Java_sp != NULL other anchor fields MUST be valid!

  // The stack may not be walkable [check with walkable() ] but the values must be valid.

  // The profiler apparently depends on this.

  //

  intptr_t* volatile _last_Java_sp;

  // Whenever we call from Java to native we can not be assured that the return

  // address that composes the last_Java_frame will be in an accessible location

  // so calls from Java to native store that pc (or one good enough to locate

  // the oopmap) in the frame anchor. Since the frames that call from Java to

  // native are never deoptimized we never need to patch the pc and so this

  // is acceptable.

  volatile  address _last_Java_pc;

  // tells whether the last Java frame is set

  // It is important that when last_Java_sp != NULL that the rest of the frame

  // anchor (including platform specific) all be valid.

  bool has_last_Java_frame() const                   { return _last_Java_sp != NULL; }

  // This is very dangerous unless sp == NULL

  // Invalidate the anchor so that has_last_frame is false

  // and no one should look at the other fields.

  void zap(void)                                     { _last_Java_sp = NULL; }

#include CPU_HEADER(javaFrameAnchor)

public:

  JavaFrameAnchor()                              { clear(); }

  JavaFrameAnchor(JavaFrameAnchor *src)          { copy(src); }

  void set_last_Java_pc(address pc)              { _last_Java_pc = pc; }

  // Assembly stub generation helpers

  static ByteSize last_Java_sp_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_sp); }

  static ByteSize last_Java_pc_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_pc); }

};

#endif // SHARE_VM_RUNTIME_JAVAFRAMEANCHOR_HPP