1 /*
2  * Copyright (c) 1997, 2019, 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_OPTO_COALESCE_HPP
26 #define SHARE_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
PhaseCoalesce(PhaseChaitin & phc)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 
lrgs(uint lidx)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
PhaseAggressiveCoalesce(PhaseChaitin & chaitin)76   PhaseAggressiveCoalesce( PhaseChaitin &chaitin ) : PhaseCoalesce(chaitin) {}
77 
verify()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_OPTO_COALESCE_HPP
118