1/* 2 * Copyright (c) 2011, 2012, 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 */ 23package org.graalvm.compiler.phases.graph; 24 25import java.util.ArrayDeque; 26import java.util.ArrayList; 27import java.util.Deque; 28import java.util.List; 29import java.util.function.Predicate; 30 31import org.graalvm.compiler.core.common.PermanentBailoutException; 32import org.graalvm.compiler.core.common.RetryableBailoutException; 33import org.graalvm.compiler.core.common.cfg.Loop; 34import org.graalvm.compiler.core.common.util.CompilationAlarm; 35import org.graalvm.compiler.nodes.AbstractEndNode; 36import org.graalvm.compiler.nodes.AbstractMergeNode; 37import org.graalvm.compiler.nodes.FixedNode; 38import org.graalvm.compiler.nodes.LoopBeginNode; 39import org.graalvm.compiler.nodes.StructuredGraph; 40import org.graalvm.compiler.nodes.cfg.Block; 41import org.graalvm.util.Equivalence; 42import org.graalvm.util.EconomicMap; 43 44public final class ReentrantBlockIterator { 45 46 public static class LoopInfo<StateT> { 47 48 public final List<StateT> endStates; 49 public final List<StateT> exitStates; 50 51 public LoopInfo(int endCount, int exitCount) { 52 endStates = new ArrayList<>(endCount); 53 exitStates = new ArrayList<>(exitCount); 54 } 55 } 56 57 public abstract static class BlockIteratorClosure<StateT> { 58 59 protected abstract StateT getInitialState(); 60 61 protected abstract StateT processBlock(Block block, StateT currentState); 62 63 protected abstract StateT merge(Block merge, List<StateT> states); 64 65 protected abstract StateT cloneState(StateT oldState); 66 67 protected abstract List<StateT> processLoop(Loop<Block> loop, StateT initialState); 68 } 69 70 private ReentrantBlockIterator() { 71 // no instances allowed 72 } 73 74 public static <StateT> LoopInfo<StateT> processLoop(BlockIteratorClosure<StateT> closure, Loop<Block> loop, StateT initialState) { 75 EconomicMap<FixedNode, StateT> blockEndStates = apply(closure, loop.getHeader(), initialState, block -> !(block.getLoop() == loop || block.isLoopHeader())); 76 77 Block[] predecessors = loop.getHeader().getPredecessors(); 78 LoopInfo<StateT> info = new LoopInfo<>(predecessors.length - 1, loop.getExits().size()); 79 for (int i = 1; i < predecessors.length; i++) { 80 StateT endState = blockEndStates.get(predecessors[i].getEndNode()); 81 // make sure all end states are unique objects 82 info.endStates.add(closure.cloneState(endState)); 83 } 84 for (Block loopExit : loop.getExits()) { 85 assert loopExit.getPredecessorCount() == 1; 86 assert blockEndStates.containsKey(loopExit.getBeginNode()) : loopExit.getBeginNode() + " " + blockEndStates; 87 StateT exitState = blockEndStates.get(loopExit.getBeginNode()); 88 // make sure all exit states are unique objects 89 info.exitStates.add(closure.cloneState(exitState)); 90 } 91 return info; 92 } 93 94 public static <StateT> void apply(BlockIteratorClosure<StateT> closure, Block start) { 95 apply(closure, start, closure.getInitialState(), null); 96 } 97 98 public static <StateT> EconomicMap<FixedNode, StateT> apply(BlockIteratorClosure<StateT> closure, Block start, StateT initialState, Predicate<Block> stopAtBlock) { 99 Deque<Block> blockQueue = new ArrayDeque<>(); 100 /* 101 * States are stored on EndNodes before merges, and on BeginNodes after ControlSplitNodes. 102 */ 103 EconomicMap<FixedNode, StateT> states = EconomicMap.create(Equivalence.IDENTITY); 104 105 StateT state = initialState; 106 Block current = start; 107 108 StructuredGraph graph = start.getBeginNode().graph(); 109 CompilationAlarm compilationAlarm = CompilationAlarm.current(); 110 while (true) { 111 if (compilationAlarm.hasExpired()) { 112 int period = CompilationAlarm.Options.CompilationExpirationPeriod.getValue(graph.getOptions()); 113 if (period > 120) { 114 throw new PermanentBailoutException("Compilation exceeded %d seconds during CFG traversal", period); 115 } else { 116 throw new RetryableBailoutException("Compilation exceeded %d seconds during CFG traversal", period); 117 } 118 } 119 Block next = null; 120 if (stopAtBlock != null && stopAtBlock.test(current)) { 121 states.put(current.getBeginNode(), state); 122 } else { 123 state = closure.processBlock(current, state); 124 125 Block[] successors = current.getSuccessors(); 126 if (successors.length == 0) { 127 // nothing to do... 128 } else if (successors.length == 1) { 129 Block successor = successors[0]; 130 if (successor.isLoopHeader()) { 131 if (current.isLoopEnd()) { 132 // nothing to do... loop ends only lead to loop begins we've already 133 // visited 134 states.put(current.getEndNode(), state); 135 } else { 136 recurseIntoLoop(closure, blockQueue, states, state, successor); 137 } 138 } else if (current.getEndNode() instanceof AbstractEndNode) { 139 AbstractEndNode end = (AbstractEndNode) current.getEndNode(); 140 141 // add the end node and see if the merge is ready for processing 142 AbstractMergeNode merge = end.merge(); 143 if (allEndsVisited(states, current, merge)) { 144 ArrayList<StateT> mergedStates = mergeStates(states, state, current, successor, merge); 145 state = closure.merge(successor, mergedStates); 146 next = successor; 147 } else { 148 assert !states.containsKey(end); 149 states.put(end, state); 150 } 151 } else { 152 next = successor; 153 } 154 } else { 155 next = processMultipleSuccessors(closure, blockQueue, states, state, successors); 156 } 157 } 158 159 // get next queued block 160 if (next != null) { 161 current = next; 162 } else if (blockQueue.isEmpty()) { 163 return states; 164 } else { 165 current = blockQueue.removeFirst(); 166 assert current.getPredecessorCount() == 1; 167 assert states.containsKey(current.getBeginNode()); 168 state = states.removeKey(current.getBeginNode()); 169 } 170 } 171 } 172 173 private static <StateT> boolean allEndsVisited(EconomicMap<FixedNode, StateT> states, Block current, AbstractMergeNode merge) { 174 for (AbstractEndNode forwardEnd : merge.forwardEnds()) { 175 if (forwardEnd != current.getEndNode() && !states.containsKey(forwardEnd)) { 176 return false; 177 } 178 } 179 return true; 180 } 181 182 private static <StateT> Block processMultipleSuccessors(BlockIteratorClosure<StateT> closure, Deque<Block> blockQueue, EconomicMap<FixedNode, StateT> states, StateT state, Block[] successors) { 183 assert successors.length > 1; 184 for (int i = 1; i < successors.length; i++) { 185 Block successor = successors[i]; 186 blockQueue.addFirst(successor); 187 states.put(successor.getBeginNode(), closure.cloneState(state)); 188 } 189 return successors[0]; 190 } 191 192 private static <StateT> ArrayList<StateT> mergeStates(EconomicMap<FixedNode, StateT> states, StateT state, Block current, Block successor, AbstractMergeNode merge) { 193 ArrayList<StateT> mergedStates = new ArrayList<>(merge.forwardEndCount()); 194 for (Block predecessor : successor.getPredecessors()) { 195 assert predecessor == current || states.containsKey(predecessor.getEndNode()); 196 StateT endState = predecessor == current ? state : states.removeKey(predecessor.getEndNode()); 197 mergedStates.add(endState); 198 } 199 return mergedStates; 200 } 201 202 private static <StateT> void recurseIntoLoop(BlockIteratorClosure<StateT> closure, Deque<Block> blockQueue, EconomicMap<FixedNode, StateT> states, StateT state, Block successor) { 203 // recurse into the loop 204 Loop<Block> loop = successor.getLoop(); 205 LoopBeginNode loopBegin = (LoopBeginNode) loop.getHeader().getBeginNode(); 206 assert successor.getBeginNode() == loopBegin; 207 208 List<StateT> exitStates = closure.processLoop(loop, state); 209 210 int i = 0; 211 assert loop.getExits().size() == exitStates.size(); 212 for (Block exit : loop.getExits()) { 213 states.put(exit.getBeginNode(), exitStates.get(i++)); 214 blockQueue.addFirst(exit); 215 } 216 } 217} 218