1 /* 2 * Copyright (c) 2011, 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 package org.graalvm.compiler.loop.phases; 26 27 import org.graalvm.compiler.loop.LoopEx; 28 import org.graalvm.compiler.loop.LoopsData; 29 import org.graalvm.compiler.nodes.FixedNode; 30 import org.graalvm.compiler.nodes.Invoke; 31 import org.graalvm.compiler.nodes.LoopEndNode; 32 import org.graalvm.compiler.nodes.StructuredGraph; 33 import org.graalvm.compiler.nodes.cfg.Block; 34 import org.graalvm.compiler.nodes.extended.ForeignCallNode; 35 import org.graalvm.compiler.phases.BasePhase; 36 import org.graalvm.compiler.phases.tiers.MidTierContext; 37 38 public class LoopSafepointEliminationPhase extends BasePhase<MidTierContext> { 39 40 @Override 41 protected void run(StructuredGraph graph, MidTierContext context) { 42 LoopsData loops = new LoopsData(graph); 43 loops.detectedCountedLoops(); 44 for (LoopEx loop : loops.countedLoops()) { 45 if (loop.loop().getChildren().isEmpty() && loop.counted().getStamp().getBits() <= 32) { 46 boolean hasSafepoint = false; 47 for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) { 48 hasSafepoint |= loopEnd.canSafepoint(); 49 } 50 if (hasSafepoint) { 51 if (!loop.counted().counterNeverOverflows()) { 52 // Counter can overflow, need to create a guard. 53 if (context.getOptimisticOptimizations().useLoopLimitChecks(graph.getOptions()) && graph.getGuardsStage().allowsFloatingGuards()) { 54 loop.counted().createOverFlowGuard(); 55 } else { 56 // Cannot disable this safepoint, because the loop could overflow. 57 continue; 58 } 59 } 60 loop.loopBegin().disableSafepoint(); 61 } 62 } 63 } 64 for (LoopEx loop : loops.loops()) { 65 for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) { 66 Block b = loops.getCFG().blockFor(loopEnd); 67 blocks: while (b != loop.loop().getHeader()) { 68 assert b != null; 69 for (FixedNode node : b.getNodes()) { 70 if (node instanceof Invoke || (node instanceof ForeignCallNode && ((ForeignCallNode) node).isGuaranteedSafepoint())) { 71 loopEnd.disableSafepoint(); 72 break blocks; 73 } 74 } 75 b = b.getDominator(); 76 } 77 } 78 } 79 loops.deleteUnusedNodes(); 80 } 81 }