/*

 * Copyright 1997-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

class StackValue : public ResourceObj {

 private:

  BasicType _type;

  intptr_t  _i; // Blank java stack slot value

  Handle    _o; // Java stack slot value interpreted as a Handle

 public:

  StackValue(intptr_t value) {

    _type  = T_INT;

    _i     = value;

  }

  StackValue(Handle value, intptr_t scalar_replaced = 0) {

    _type    = T_OBJECT;

    _i       = scalar_replaced;

    _o       = value;

    assert(_i == 0 || _o.is_null(), "not null object should not be marked as scalar replaced");

  }

  StackValue() {

    _type   = T_CONFLICT;

    _i      = 0;

  }

  // Only used during deopt- preserve object type.

  StackValue(intptr_t o, BasicType t) {

    assert(t == T_OBJECT, "should not be used");

    _type   = t;

    _i      = o;

  }

  Handle get_obj() const {

    assert(type() == T_OBJECT, "type check");

    return _o;

  }

  bool obj_is_scalar_replaced() const {

    assert(type() == T_OBJECT, "type check");

    return _i != 0;

  }

  void set_obj(Handle value) {

    assert(type() == T_OBJECT, "type check");

    _o = value;

  }

  intptr_t get_int() const {

    assert(type() == T_INT, "type check");

    return _i;

  }

  // For special case in deopt.

  intptr_t get_int(BasicType t) const {

    assert(t == T_OBJECT && type() == T_OBJECT, "type check");

    return _i;

  }

  void set_int(intptr_t value) {

    assert(type() == T_INT, "type check");

    _i = value;

  }

  BasicType type() const { return  _type; }

  bool equal(StackValue *value) {

    if (_type != value->_type) return false;

    if (_type == T_OBJECT)

      return (_o == value->_o);

    else {

      assert(_type == T_INT, "sanity check");

      // [phh] compare only low addressed portions of intptr_t slots

      return (*(int *)&_i == *(int *)&value->_i);

    }

  }

  static StackValue* create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv);

  static BasicLock*  resolve_monitor_lock(const frame* fr, Location location);

#ifndef PRODUCT

 public:

  // Printing

  void print_on(outputStream* st) const;

#endif

};