1 /*
2 * Copyright (c) 2014, 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 #include "opto/cfgnode.hpp"
26 #include "opto/phaseX.hpp"
27 #include "opto/replacednodes.hpp"
28
29 void ReplacedNodes::allocate_if_necessary() {
30 if (_replaced_nodes == NULL) {
31 _replaced_nodes = new GrowableArray<ReplacedNode>();
32 }
33 }
34
35 bool ReplacedNodes::is_empty() const {
36 return _replaced_nodes == NULL || _replaced_nodes->length() == 0;
37 }
38
39 bool ReplacedNodes::has_node(const ReplacedNode& r) const {
40 return _replaced_nodes->find(r) != -1;
41 }
42
43 bool ReplacedNodes::has_target_node(Node* n) const {
44 for (int i = 0; i < _replaced_nodes->length(); i++) {
45 if (_replaced_nodes->at(i).improved() == n) {
46 return true;
47 }
48 }
49 return false;
50 }
51
52 // Record replaced node if not seen before
53 void ReplacedNodes::record(Node* initial, Node* improved) {
54 allocate_if_necessary();
55 ReplacedNode r(initial, improved);
56 if (!has_node(r)) {
57 _replaced_nodes->push(r);
58 }
59 }
60
61 // Copy replaced nodes from one map to another. idx is used to
62 // identify nodes that are too new to be of interest in the target
63 // node list.
64 void ReplacedNodes::transfer_from(const ReplacedNodes& other, uint idx) {
65 if (other.is_empty()) {
66 return;
67 }
68 allocate_if_necessary();
69 for (int i = 0; i < other._replaced_nodes->length(); i++) {
70 ReplacedNode replaced = other._replaced_nodes->at(i);
71 // Only transfer the nodes that can actually be useful
72 if (!has_node(replaced) && (replaced.initial()->_idx < idx || has_target_node(replaced.initial()))) {
73 _replaced_nodes->push(replaced);
74 }
75 }
76 }
77
78 void ReplacedNodes::clone() {
79 if (_replaced_nodes != NULL) {
80 GrowableArray<ReplacedNode>* replaced_nodes_clone = new GrowableArray<ReplacedNode>();
81 replaced_nodes_clone->appendAll(_replaced_nodes);
82 _replaced_nodes = replaced_nodes_clone;
83 }
84 }
85
86 void ReplacedNodes::reset() {
87 if (_replaced_nodes != NULL) {
88 _replaced_nodes->clear();
89 }
90 }
91
92 // Perfom node replacement (used when returning to caller)
93 void ReplacedNodes::apply(Node* n) {
94 if (is_empty()) {
95 return;
96 }
97 for (int i = 0; i < _replaced_nodes->length(); i++) {
98 ReplacedNode replaced = _replaced_nodes->at(i);
99 n->replace_edge(replaced.initial(), replaced.improved());
100 }
101 }
102
103 static void enqueue_use(Node* n, Node* use, Unique_Node_List& work) {
104 if (use->is_Phi()) {
105 Node* r = use->in(0);
106 assert(r->is_Region(), "Phi should have Region");
107 for (uint i = 1; i < use->req(); i++) {
108 if (use->in(i) == n) {
109 work.push(r->in(i));
110 }
111 }
112 } else {
113 work.push(use);
114 }
115 }
116
117 // Perfom node replacement following late inlining
118 void ReplacedNodes::apply(Compile* C, Node* ctl) {
119 // ctl is the control on exit of the method that was late inlined
120 if (is_empty()) {
121 return;
122 }
123 for (int i = 0; i < _replaced_nodes->length(); i++) {
124 ReplacedNode replaced = _replaced_nodes->at(i);
125 Node* initial = replaced.initial();
126 Node* improved = replaced.improved();
127 assert (ctl != NULL && !ctl->is_top(), "replaced node should have actual control");
128
129 ResourceMark rm;
130 Unique_Node_List work;
131 // Go over all the uses of the node that is considered for replacement...
132 for (DUIterator j = initial->outs(); initial->has_out(j); j++) {
133 Node* use = initial->out(j);
134
135 if (use == improved || use->outcnt() == 0) {
136 continue;
137 }
138 work.clear();
139 enqueue_use(initial, use, work);
140 bool replace = true;
141 // Check that this use is dominated by ctl. Go ahead with the
142 // replacement if it is.
143 while (work.size() != 0 && replace) {
144 Node* n = work.pop();
145 if (use->outcnt() == 0) {
146 continue;
147 }
148 if (n->is_CFG() || (n->in(0) != NULL && !n->in(0)->is_top())) {
149 int depth = 0;
150 Node *m = n;
151 if (!n->is_CFG()) {
152 n = n->in(0);
153 }
154 assert(n->is_CFG(), "should be CFG now");
155 while(n != ctl) {
156 n = IfNode::up_one_dom(n);
157 depth++;
158 // limit search depth
159 if (depth >= 100 || n == NULL) {
160 replace = false;
161 break;
162 }
163 }
164 } else {
165 for (DUIterator k = n->outs(); n->has_out(k); k++) {
166 enqueue_use(n, n->out(k), work);
167 }
168 }
169 }
170 if (replace) {
171 bool is_in_table = C->initial_gvn()->hash_delete(use);
172 int replaced = use->replace_edge(initial, improved);
173 if (is_in_table) {
174 C->initial_gvn()->hash_find_insert(use);
175 }
176 C->record_for_igvn(use);
177
178 assert(replaced > 0, "inconsistent");
179 --j;
180 }
181 }
182 }
183 }
184
185 void ReplacedNodes::dump(outputStream *st) const {
186 if (!is_empty()) {
187 tty->print("replaced nodes: ");
188 for (int i = 0; i < _replaced_nodes->length(); i++) {
189 tty->print("%d->%d", _replaced_nodes->at(i).initial()->_idx, _replaced_nodes->at(i).improved()->_idx);
190 if (i < _replaced_nodes->length()-1) {
191 tty->print(",");
192 }
193 }
194 }
195 }
196
197 // Merge 2 list of replaced node at a point where control flow paths merge
198 void ReplacedNodes::merge_with(const ReplacedNodes& other) {
199 if (is_empty()) {
200 return;
201 }
202 if (other.is_empty()) {
203 reset();
204 return;
205 }
206 int shift = 0;
207 int len = _replaced_nodes->length();
208 for (int i = 0; i < len; i++) {
209 if (!other.has_node(_replaced_nodes->at(i))) {
210 shift++;
211 } else if (shift > 0) {
212 _replaced_nodes->at_put(i-shift, _replaced_nodes->at(i));
213 }
214 }
215 if (shift > 0) {
216 _replaced_nodes->trunc_to(len - shift);
217 }
218 }
219