/*

 * Copyright (c) 1999, 2012, 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.

 *

 */

#include "precompiled.hpp"

#include "opto/locknode.hpp"

#include "opto/parse.hpp"

#include "opto/rootnode.hpp"

#include "opto/runtime.hpp"

//=============================================================================

const RegMask &BoxLockNode::in_RegMask(uint i) const {

  return _inmask;

}

const RegMask &BoxLockNode::out_RegMask() const {

  return *Matcher::idealreg2regmask[Op_RegP];

}

uint BoxLockNode::size_of() const { return sizeof(*this); }

BoxLockNode::BoxLockNode( int slot ) : Node( Compile::current()->root() ),

                                       _slot(slot), _is_eliminated(false) {

  init_class_id(Class_BoxLock);

  init_flags(Flag_rematerialize);

  OptoReg::Name reg = OptoReg::stack2reg(_slot);

  _inmask.Insert(reg);

}

//-----------------------------hash--------------------------------------------

uint BoxLockNode::hash() const {

  if (EliminateNestedLocks)

    return NO_HASH; // Each locked region has own BoxLock node

  return Node::hash() + _slot + (_is_eliminated ? Compile::current()->fixed_slots() : 0);

}

//------------------------------cmp--------------------------------------------

uint BoxLockNode::cmp( const Node &n ) const {

  if (EliminateNestedLocks)

    return (&n == this); // Always fail except on self

  const BoxLockNode &bn = (const BoxLockNode &)n;

  return bn._slot == _slot && bn._is_eliminated == _is_eliminated;

}

BoxLockNode* BoxLockNode::box_node(Node* box) {

  // Chase down the BoxNode after RA which may spill box nodes.

  while (!box->is_BoxLock()) {

    //    if (box_node->is_SpillCopy()) {

    //      Node *m = box_node->in(1);

    //      if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_StoreP) {

    //        box_node = m->in(m->as_Mach()->operand_index(2));

    //        continue;

    //      }

    //    }

    assert(box->is_SpillCopy() || box->is_Phi(), "Bad spill of Lock.");

    // Only BoxLock nodes with the same stack slot are merged.

    // So it is enough to trace one path to find the slot value.

    box = box->in(1);

  }

  return box->as_BoxLock();

}

OptoReg::Name BoxLockNode::reg(Node* box) {

  return box_node(box)->in_RegMask(0).find_first_elem();

}

// Is BoxLock node used for one simple lock region (same box and obj)?

bool BoxLockNode::is_simple_lock_region(LockNode** unique_lock, Node* obj) {

  LockNode* lock = NULL;

  bool has_one_lock = false;

  for (uint i = 0; i < this->outcnt(); i++) {

    Node* n = this->raw_out(i);

    assert(!n->is_Phi(), "should not merge BoxLock nodes");

    if (n->is_AbstractLock()) {

      AbstractLockNode* alock = n->as_AbstractLock();

      // Check lock's box since box could be referenced by Lock's debug info.

      if (alock->box_node() == this) {

        if (alock->obj_node()->eqv_uncast(obj)) {

          if ((unique_lock != NULL) && alock->is_Lock()) {

            if (lock == NULL) {

              lock = alock->as_Lock();

              has_one_lock = true;

            } else if (lock != alock->as_Lock()) {

              has_one_lock = false;

            }

          }

        } else {

          return false; // Different objects

        }

      }

    }

  }

#ifdef ASSERT

  // Verify that FastLock and Safepoint reference only this lock region.

  for (uint i = 0; i < this->outcnt(); i++) {

    Node* n = this->raw_out(i);

    if (n->is_FastLock()) {

      FastLockNode* flock = n->as_FastLock();

      assert((flock->box_node() == this) && flock->obj_node()->eqv_uncast(obj),"");

    }

    // Don't check monitor info in safepoints since the referenced object could

    // be different from the locked object. It could be Phi node of different

    // cast nodes which point to this locked object.

    // We assume that no other objects could be referenced in monitor info

    // associated with this BoxLock node because all associated locks and

    // unlocks are reference only this one object.

  }

#endif

  if (unique_lock != NULL && has_one_lock) {

    *unique_lock = lock;

  }

  return true;

}

//=============================================================================

//-----------------------------hash--------------------------------------------

uint FastLockNode::hash() const { return NO_HASH; }

//------------------------------cmp--------------------------------------------

uint FastLockNode::cmp( const Node &n ) const {

  return (&n == this);                // Always fail except on self

}

//=============================================================================

//-----------------------------hash--------------------------------------------

uint FastUnlockNode::hash() const { return NO_HASH; }

//------------------------------cmp--------------------------------------------

uint FastUnlockNode::cmp( const Node &n ) const {

  return (&n == this);                // Always fail except on self

}

//

// Create a counter which counts the number of times this lock is acquired

//

void FastLockNode::create_lock_counter(JVMState* state) {

  BiasedLockingNamedCounter* blnc = (BiasedLockingNamedCounter*)

           OptoRuntime::new_named_counter(state, NamedCounter::BiasedLockingCounter);

  _counters = blnc->counters();

}

//=============================================================================

//------------------------------do_monitor_enter-------------------------------

void Parse::do_monitor_enter() {

  kill_dead_locals();

  // Null check; get casted pointer.

  // Check for locking null object

  if (stopped()) return;

  // the monitor object is not part of debug info expression stack

  pop();

  // Insert a FastLockNode which takes as arguments the current thread pointer,

  // the obj pointer & the address of the stack slot pair used for the lock.

  shared_lock(obj);

}

//------------------------------do_monitor_exit--------------------------------

void Parse::do_monitor_exit() {

  kill_dead_locals();

  pop();                        // Pop oop to unlock

  // Because monitors are guaranteed paired (else we bail out), we know

  // the matching Lock for this Unlock.  Hence we know there is no need

  // for a null check on Unlock.

  shared_unlock(map()->peek_monitor_box(), map()->peek_monitor_obj());

}