/*

 * Copyright (c) 2002, 2007, 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.

 *

 */

class JavaThread;

//

// RegisterMap

//

// A companion structure used for stack traversal. The RegisterMap contains

// misc. information needed in order to do correct stack traversal of stack

// frames.  Hence, it must always be passed in as an argument to

// frame::sender(RegisterMap*).

//

// In particular,

//   1) It provides access to the thread for which the stack belongs.  The

//      thread object is needed in order to get sender of a deoptimized frame.

//

//   2) It is used to pass information from a callee frame to its caller

//      frame about how the frame should be traversed.  This is used to let

//      the caller frame take care of calling oops-do of out-going

//      arguments, when the callee frame is not instantiated yet.  This

//      happens, e.g., when a compiled frame calls into

//      resolve_virtual_call.  (Hence, it is critical that the same

//      RegisterMap object is used for the entire stack walk.  Normally,

//      this is hidden by using the StackFrameStream.)  This is used when

//      doing follow_oops and oops_do.

//

//   3) The RegisterMap keeps track of the values of callee-saved registers

//      from frame to frame (hence, the name).  For some stack traversal the

//      values of the callee-saved registers does not matter, e.g., if you

//      only need the static properies such as frame type, pc, and such.

//      Updating of the RegisterMap can be turned off by instantiating the

//      register map as: RegisterMap map(thread, false);

class RegisterMap : public StackObj {

 public:

    typedef julong LocationValidType;

  enum {

    reg_count = ConcreteRegisterImpl::number_of_registers,

    location_valid_type_size = sizeof(LocationValidType)*8,

    location_valid_size = (reg_count+location_valid_type_size-1)/location_valid_type_size

  };

 private:

  intptr_t*    _location[reg_count];    // Location of registers (intptr_t* looks better than address in the debugger)

  LocationValidType _location_valid[location_valid_size];

  bool        _include_argument_oops;   // Should include argument_oop marked locations for compiler

  JavaThread* _thread;                  // Reference to current thread

  bool        _update_map;              // Tells if the register map need to be

                                        // updated when traversing the stack

#ifdef ASSERT

  void check_location_valid();

#else

  void check_location_valid() {}

#endif

 public:

  debug_only(intptr_t* _update_for_id;) // Assert that RegisterMap is not updated twice for same frame

  RegisterMap(JavaThread *thread, bool update_map = true);

  RegisterMap(const RegisterMap* map);

  address location(VMReg reg) const {

    int index = reg->value() / location_valid_type_size;

    assert(0 <= reg->value() && reg->value() < reg_count, "range check");

    assert(0 <= index && index < location_valid_size, "range check");

    if (_location_valid[index] & ((LocationValidType)1 << (reg->value() % location_valid_type_size))) {

      return (address) _location[reg->value()];

    } else {

      return pd_location(reg);

    }

  }

  void set_location(VMReg reg, address loc) {

    int index = reg->value() / location_valid_type_size;

    assert(0 <= reg->value() && reg->value() < reg_count, "range check");

    assert(0 <= index && index < location_valid_size, "range check");

    assert(_update_map, "updating map that does not need updating");

    _location[reg->value()] = (intptr_t*) loc;

    _location_valid[index] |= ((LocationValidType)1 << (reg->value() % location_valid_type_size));

    check_location_valid();

  }

  // Called by an entry frame.

  void clear();

  bool include_argument_oops() const      { return _include_argument_oops; }

  void set_include_argument_oops(bool f)  { _include_argument_oops = f; }

  JavaThread *thread() const { return _thread; }

  bool update_map()    const { return _update_map; }

  void print_on(outputStream* st) const;

  void print() const;

  // the following contains the definition of pd_xxx methods

# include "incls/_registerMap_pd.hpp.incl"

};