/*

 * Copyright (c) 1997, 2013, 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_OPTO_COALESCE_HPP

#define SHARE_VM_OPTO_COALESCE_HPP

#include "opto/phase.hpp"

class LoopTree;

class LRG;

class Matcher;

class PhaseIFG;

class PhaseCFG;

//------------------------------PhaseCoalesce----------------------------------

class PhaseCoalesce : public Phase {

protected:

  PhaseChaitin &_phc;

public:

  // Coalesce copies

  PhaseCoalesce(PhaseChaitin &phc)

  : Phase(Coalesce)

  , _phc(phc) {}

  virtual void verify() = 0;

  // Coalesce copies

  void coalesce_driver();

  // Coalesce copies in this block

  virtual void coalesce(Block *b) = 0;

  // Attempt to coalesce live ranges defined by these 2

  void combine_these_two(Node *n1, Node *n2);

  LRG &lrgs(uint lidx) { return _phc.lrgs(lidx); }

#ifndef PRODUCT

  // Dump internally name

  void dump(Node *n) const;

  // Dump whole shebang

  void dump() const;

#endif

};

//------------------------------PhaseAggressiveCoalesce------------------------

// Aggressively, pessimistic coalesce copies.  Aggressive means ignore graph

// colorability; perhaps coalescing to the point of forcing a spill.

// Pessimistic means we cannot coalesce if 2 live ranges interfere.  This

// implies we do not hit a fixed point right away.

class PhaseAggressiveCoalesce : public PhaseCoalesce {

  uint _unique;

public:

  // Coalesce copies

  PhaseAggressiveCoalesce( PhaseChaitin &chaitin ) : PhaseCoalesce(chaitin) {}

  virtual void verify() { };

  // Aggressively coalesce copies in this block

  virtual void coalesce( Block *b );

  // Where I fail to coalesce, manifest virtual copies as the Real Thing

  void insert_copies( Matcher &matcher );

  // Copy insertion needs some smarts in case live ranges overlap

  void insert_copy_with_overlap( Block *b, Node *copy, uint dst_name, uint src_name );

};

//------------------------------PhaseConservativeCoalesce----------------------

// Conservatively, pessimistic coalesce copies.  Conservative means do not

// coalesce if the resultant live range will be uncolorable.  Pessimistic

// means we cannot coalesce if 2 live ranges interfere.  This implies we do

// not hit a fixed point right away.

class PhaseConservativeCoalesce : public PhaseCoalesce {

  IndexSet _ulr;               // Union live range interferences

public:

  // Coalesce copies

  PhaseConservativeCoalesce( PhaseChaitin &chaitin );

  virtual void verify();

  // Conservatively coalesce copies in this block

  virtual void coalesce( Block *b );

  // Coalesce this chain of copies away

  bool copy_copy( Node *dst_copy, Node *src_copy, Block *b, uint bindex );

  void union_helper( Node *lr1_node, Node *lr2_node, uint lr1, uint lr2, Node *src_def, Node *dst_copy, Node *src_copy, Block *b, uint bindex );

  uint compute_separating_interferences(Node *dst_copy, Node *src_copy, Block *b, uint bindex, RegMask &rm, uint rm_size, uint reg_degree, uint lr1, uint lr2);

  void update_ifg(uint lr1, uint lr2, IndexSet *n_lr1, IndexSet *n_lr2);

};

#endif // SHARE_VM_OPTO_COALESCE_HPP