1 /*
   2  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_COALESCE_HPP
  26 #define SHARE_VM_OPTO_COALESCE_HPP
  27 
  28 #include "opto/phase.hpp"
  29 
  30 class LoopTree;
  31 class LRG;
  32 class LRG_List;
  33 class Matcher;
  34 class PhaseIFG;
  35 class PhaseCFG;
  36 
  37 //------------------------------PhaseCoalesce----------------------------------
  38 class PhaseCoalesce : public Phase {
  39 protected:
  40   PhaseChaitin &_phc;
  41 
  42 public:
  43   // Coalesce copies
  44   PhaseCoalesce( PhaseChaitin &chaitin ) : Phase(Coalesce), _phc(chaitin) { }
  45 
  46   virtual void verify() = 0;
  47 
  48   // Coalesce copies
  49   void coalesce_driver( );
  50 
  51   // Coalesce copies in this block
  52   virtual void coalesce( Block *b ) = 0;
  53 
  54   // Attempt to coalesce live ranges defined by these 2
  55   void combine_these_two( Node *n1, Node *n2 );
  56 
  57   LRG &lrgs( uint lidx ) { return _phc.lrgs(lidx); }
  58 #ifndef PRODUCT
  59   // Dump internally name
  60   void dump( Node *n ) const;
  61   // Dump whole shebang
  62   void dump() const;
  63 #endif
  64 };
  65 
  66 //------------------------------PhaseAggressiveCoalesce------------------------
  67 // Aggressively, pessimistic coalesce copies.  Aggressive means ignore graph
  68 // colorability; perhaps coalescing to the point of forcing a spill.
  69 // Pessimistic means we cannot coalesce if 2 live ranges interfere.  This
  70 // implies we do not hit a fixed point right away.
  71 class PhaseAggressiveCoalesce : public PhaseCoalesce {
  72   uint _unique;
  73 public:
  74   // Coalesce copies
  75   PhaseAggressiveCoalesce( PhaseChaitin &chaitin ) : PhaseCoalesce(chaitin) {}
  76 
  77   virtual void verify() { };
  78 
  79   // Aggressively coalesce copies in this block
  80   virtual void coalesce( Block *b );
  81 
  82   // Where I fail to coalesce, manifest virtual copies as the Real Thing
  83   void insert_copies( Matcher &matcher );
  84 
  85   // Copy insertion needs some smarts in case live ranges overlap
  86   void insert_copy_with_overlap( Block *b, Node *copy, uint dst_name, uint src_name );
  87 };
  88 
  89 
  90 //------------------------------PhaseConservativeCoalesce----------------------
  91 // Conservatively, pessimistic coalesce copies.  Conservative means do not
  92 // coalesce if the resultant live range will be uncolorable.  Pessimistic
  93 // means we cannot coalesce if 2 live ranges interfere.  This implies we do
  94 // not hit a fixed point right away.
  95 class PhaseConservativeCoalesce : public PhaseCoalesce {
  96   IndexSet _ulr;               // Union live range interferences
  97 public:
  98   // Coalesce copies
  99   PhaseConservativeCoalesce( PhaseChaitin &chaitin );
 100 
 101   virtual void verify();
 102 
 103   // Conservatively coalesce copies in this block
 104   virtual void coalesce( Block *b );
 105 
 106   // Coalesce this chain of copies away
 107   bool copy_copy( Node *dst_copy, Node *src_copy, Block *b, uint bindex );
 108 
 109   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 );
 110 
 111   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);
 112 
 113   void update_ifg(uint lr1, uint lr2, IndexSet *n_lr1, IndexSet *n_lr2);
 114 };
 115 
 116 #endif // SHARE_VM_OPTO_COALESCE_HPP