1 /*
   2  * Copyright (c) 1997, 2013, 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.
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   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
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  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
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  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 Matcher;
  33 class PhaseIFG;
  34 class PhaseCFG;
  35 
  36 //------------------------------PhaseCoalesce----------------------------------
  37 class PhaseCoalesce : public Phase {
  38 protected:
  39   PhaseChaitin &_phc;
  40 
  41 public:
  42   // Coalesce copies
  43   PhaseCoalesce(PhaseChaitin &phc)
  44   : Phase(Coalesce)
  45   , _phc(phc) {}
  46 
  47   virtual void verify() = 0;
  48 
  49   // Coalesce copies
  50   void coalesce_driver();
  51 
  52   // Coalesce copies in this block
  53   virtual void coalesce(Block *b) = 0;
  54 
  55   // Attempt to coalesce live ranges defined by these 2
  56   void combine_these_two(Node *n1, Node *n2);
  57 
  58   LRG &lrgs(uint lidx) { return _phc.lrgs(lidx); }
  59 #ifndef PRODUCT
  60   // Dump internally name
  61   void dump(Node *n) const;
  62   // Dump whole shebang
  63   void dump() const;
  64 #endif
  65 };
  66 
  67 //------------------------------PhaseAggressiveCoalesce------------------------
  68 // Aggressively, pessimistic coalesce copies.  Aggressive means ignore graph
  69 // colorability; perhaps coalescing to the point of forcing a spill.
  70 // Pessimistic means we cannot coalesce if 2 live ranges interfere.  This
  71 // implies we do not hit a fixed point right away.
  72 class PhaseAggressiveCoalesce : public PhaseCoalesce {
  73   uint _unique;
  74 public:
  75   // Coalesce copies
  76   PhaseAggressiveCoalesce( PhaseChaitin &chaitin ) : PhaseCoalesce(chaitin) {}
  77 
  78   virtual void verify() { };
  79 
  80   // Aggressively coalesce copies in this block
  81   virtual void coalesce( Block *b );
  82 
  83   // Where I fail to coalesce, manifest virtual copies as the Real Thing
  84   void insert_copies( Matcher &matcher );
  85 
  86   // Copy insertion needs some smarts in case live ranges overlap
  87   void insert_copy_with_overlap( Block *b, Node *copy, uint dst_name, uint src_name );
  88 };
  89 
  90 
  91 //------------------------------PhaseConservativeCoalesce----------------------
  92 // Conservatively, pessimistic coalesce copies.  Conservative means do not
  93 // coalesce if the resultant live range will be uncolorable.  Pessimistic
  94 // means we cannot coalesce if 2 live ranges interfere.  This implies we do
  95 // not hit a fixed point right away.
  96 class PhaseConservativeCoalesce : public PhaseCoalesce {
  97   IndexSet _ulr;               // Union live range interferences
  98 public:
  99   // Coalesce copies
 100   PhaseConservativeCoalesce( PhaseChaitin &chaitin );
 101 
 102   virtual void verify();
 103 
 104   // Conservatively coalesce copies in this block
 105   virtual void coalesce( Block *b );
 106 
 107   // Coalesce this chain of copies away
 108   bool copy_copy( Node *dst_copy, Node *src_copy, Block *b, uint bindex );
 109 
 110   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 );
 111 
 112   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);
 113 
 114   void update_ifg(uint lr1, uint lr2, IndexSet *n_lr1, IndexSet *n_lr2);
 115 };
 116 
 117 #endif // SHARE_VM_OPTO_COALESCE_HPP