1/*
2 * Copyright (c) 2014, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25#ifndef SHARE_OPTO_REPLACEDNODES_HPP
26#define SHARE_OPTO_REPLACEDNODES_HPP
27
28#include "opto/connode.hpp"
29
30// During parsing, when a node is "improved",
31// GraphKit::replace_in_map() is called to update the current map so
32// that the improved node is used from that point
33// on. GraphKit::replace_in_map() doesn't operate on the callers maps
34// and so some optimization opportunities may be lost. The
35// ReplacedNodes class addresses that problem.
36//
37// A ReplacedNodes object is a list of pair of nodes. Every
38// SafePointNode carries a ReplacedNodes object. Every time
39// GraphKit::replace_in_map() is called, a new pair of nodes is pushed
40// on the list of replaced nodes. When control flow paths merge, their
41// replaced nodes are also merged. When parsing exits a method to
42// return to a caller, the replaced nodes on the exit path are used to
43// update the caller's map.
44class ReplacedNodes {
45 private:
46 class ReplacedNode {
47 private:
48 Node* _initial;
49 Node* _improved;
50 public:
51 ReplacedNode() : _initial(NULL), _improved(NULL) {}
52 ReplacedNode(Node* initial, Node* improved) : _initial(initial), _improved(improved) {}
53 Node* initial() const { return _initial; }
54 Node* improved() const { return _improved; }
55
56 bool operator==(const ReplacedNode& other) {
57 return _initial == other._initial && _improved == other._improved;
58 }
59 };
60 GrowableArray<ReplacedNode>* _replaced_nodes;
61
62 void allocate_if_necessary();
63 bool has_node(const ReplacedNode& r) const;
64 bool has_target_node(Node* n) const;
65
66 public:
67 ReplacedNodes()
68 : _replaced_nodes(NULL) {}
69
70 void clone();
71 void record(Node* initial, Node* improved);
72 void transfer_from(const ReplacedNodes& other, uint idx);
73 void reset();
74 void apply(Node* n, uint idx);
75 void merge_with(const ReplacedNodes& other);
76 bool is_empty() const;
77 void dump(outputStream *st) const;
78 void apply(Compile* C, Node* ctl);
79};
80
81#endif // SHARE_OPTO_REPLACEDNODES_HPP
82