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 /*

  * Copyright (c) 1999, 2010, 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.

   Node *obj = do_null_check(peek(), T_OBJECT);

   // 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());

 }