1 /* 2 * Copyright (c) 2016, 2023, 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 "precompiled.hpp" 26 #include "memory/resourceArea.hpp" 27 #include "opto/cfgnode.hpp" 28 #include "opto/phaseX.hpp" 29 #include "opto/replacednodes.hpp" 30 31 void ReplacedNodes::allocate_if_necessary() { 32 if (_replaced_nodes == nullptr) { 33 _replaced_nodes = new GrowableArray<ReplacedNode>(); 34 } 35 } 36 37 bool ReplacedNodes::is_empty() const { 38 return _replaced_nodes == nullptr || _replaced_nodes->length() == 0; 39 } 40 41 bool ReplacedNodes::has_node(const ReplacedNode& r) const { 42 return _replaced_nodes->find(r) != -1; 43 } 44 45 bool ReplacedNodes::has_target_node(Node* n) const { 46 for (int i = 0; i < _replaced_nodes->length(); i++) { 47 if (_replaced_nodes->at(i).improved() == n) { 48 return true; 49 } 50 } 51 return false; 52 } 53 54 // Record replaced node if not seen before 55 void ReplacedNodes::record(Node* initial, Node* improved) { 56 allocate_if_necessary(); 57 ReplacedNode r(initial, improved); 58 if (!has_node(r)) { 59 _replaced_nodes->push(r); 60 } 61 } 62 63 // Copy replaced nodes from one map to another. idx is used to 64 // identify nodes that are too new to be of interest in the target 65 // node list. 66 void ReplacedNodes::transfer_from(const ReplacedNodes& other, uint idx) { 67 if (other.is_empty()) { 68 return; 69 } 70 allocate_if_necessary(); 71 for (int i = 0; i < other._replaced_nodes->length(); i++) { 72 ReplacedNode replaced = other._replaced_nodes->at(i); 73 // Only transfer the nodes that can actually be useful 74 if (!has_node(replaced) && (replaced.initial()->_idx < idx || has_target_node(replaced.initial()))) { 75 _replaced_nodes->push(replaced); 76 } 77 } 78 } 79 80 void ReplacedNodes::clone() { 81 if (_replaced_nodes != nullptr) { 82 GrowableArray<ReplacedNode>* replaced_nodes_clone = new GrowableArray<ReplacedNode>(); 83 replaced_nodes_clone->appendAll(_replaced_nodes); 84 _replaced_nodes = replaced_nodes_clone; 85 } 86 } 87 88 void ReplacedNodes::reset() { 89 if (_replaced_nodes != nullptr) { 90 _replaced_nodes->clear(); 91 } 92 } 93 94 // Perform node replacement (used when returning to caller) 95 void ReplacedNodes::apply(Node* n, uint idx) { 96 if (is_empty()) { 97 return; 98 } 99 for (int i = 0; i < _replaced_nodes->length(); i++) { 100 ReplacedNode replaced = _replaced_nodes->at(i); 101 // Only apply if improved node was created in a callee to avoid 102 // issues with irreducible loops in the caller 103 if (replaced.improved()->_idx >= idx) { 104 n->replace_edge(replaced.initial(), replaced.improved()); 105 } 106 } 107 } 108 109 static void enqueue_use(Node* n, Node* use, Unique_Node_List& work) { 110 if (use->is_Phi()) { 111 Node* r = use->in(0); 112 assert(r->is_Region(), "Phi should have Region"); 113 for (uint i = 1; i < use->req(); i++) { 114 if (use->in(i) == n) { 115 work.push(r->in(i)); 116 } 117 } 118 } else { 119 work.push(use); 120 } 121 } 122 123 // Perform node replacement following late inlining. 124 void ReplacedNodes::apply(Compile* C, Node* ctl) { 125 // ctl is the control on exit of the method that was late inlined 126 if (is_empty()) { 127 return; 128 } 129 for (int i = 0; i < _replaced_nodes->length(); i++) { 130 ReplacedNode replaced = _replaced_nodes->at(i); 131 Node* initial = replaced.initial(); 132 Node* improved = replaced.improved(); 133 assert (ctl != nullptr && !ctl->is_top(), "replaced node should have actual control"); 134 135 ResourceMark rm; 136 Unique_Node_List work; 137 // Go over all the uses of the node that is considered for replacement... 138 for (DUIterator j = initial->outs(); initial->has_out(j); j++) { 139 Node* use = initial->out(j); 140 141 if (use == improved || use->outcnt() == 0) { 142 continue; 143 } 144 work.clear(); 145 enqueue_use(initial, use, work); 146 bool replace = true; 147 // Check that this use is dominated by ctl. Go ahead with the replacement if it is. 148 DEBUG_ONLY(uint loop_count = 0); 149 while (work.size() != 0 && replace) { 150 Node* n = work.pop(); 151 if (use->outcnt() == 0) { 152 continue; 153 } 154 if (n->is_CFG() || (n->in(0) != nullptr && !n->in(0)->is_top())) { 155 // Skip projections, since some of the multi nodes aren't CFG (e.g., LoadStore and SCMemProj). 156 if (n->is_Proj()) { 157 n = n->in(0); 158 } 159 if (!n->is_CFG()) { 160 n = n->in(0); 161 } 162 assert(n->is_CFG(), "should be CFG now"); 163 int depth = 0; 164 while(n != ctl) { 165 n = IfNode::up_one_dom(n); 166 depth++; 167 // limit search depth 168 if (depth >= 100 || n == nullptr) { 169 replace = false; 170 break; 171 } 172 } 173 } else { 174 for (DUIterator k = n->outs(); n->has_out(k); k++) { 175 enqueue_use(n, n->out(k), work); 176 } 177 } 178 assert(loop_count++ < K, "infinite loop in ReplacedNodes::apply"); 179 } 180 if (replace) { 181 bool is_in_table = C->initial_gvn()->hash_delete(use); 182 int replaced = use->replace_edge(initial, improved); 183 if (is_in_table) { 184 C->initial_gvn()->hash_find_insert(use); 185 } 186 C->record_for_igvn(use); 187 188 assert(replaced > 0, "inconsistent"); 189 --j; 190 } 191 } 192 } 193 } 194 195 void ReplacedNodes::dump(outputStream *st) const { 196 if (!is_empty()) { 197 st->print("replaced nodes: "); 198 for (int i = 0; i < _replaced_nodes->length(); i++) { 199 st->print("%d->%d", _replaced_nodes->at(i).initial()->_idx, _replaced_nodes->at(i).improved()->_idx); 200 if (i < _replaced_nodes->length()-1) { 201 st->print(","); 202 } 203 } 204 } 205 } 206 207 // Merge 2 list of replaced node at a point where control flow paths merge 208 void ReplacedNodes::merge_with(const ReplacedNodes& other) { 209 if (is_empty()) { 210 return; 211 } 212 if (other.is_empty()) { 213 reset(); 214 return; 215 } 216 int shift = 0; 217 int len = _replaced_nodes->length(); 218 for (int i = 0; i < len; i++) { 219 if (!other.has_node(_replaced_nodes->at(i))) { 220 shift++; 221 } else if (shift > 0) { 222 _replaced_nodes->at_put(i-shift, _replaced_nodes->at(i)); 223 } 224 } 225 if (shift > 0) { 226 _replaced_nodes->trunc_to(len - shift); 227 } 228 }