1 /* 2 * Copyright (c) 2015, 2016, 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 package org.graalvm.compiler.nodes; 24 25 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_IGNORED; 26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_IGNORED; 27 28 import java.util.List; 29 30 import org.graalvm.compiler.core.common.spi.ConstantFieldProvider; 31 import org.graalvm.compiler.core.common.type.Stamp; 32 import org.graalvm.compiler.graph.Node; 33 import org.graalvm.compiler.graph.NodeClass; 34 import org.graalvm.compiler.graph.spi.Canonicalizable; 35 import org.graalvm.compiler.graph.spi.CanonicalizerTool; 36 import org.graalvm.compiler.nodeinfo.NodeInfo; 37 import org.graalvm.compiler.nodes.calc.FloatingNode; 38 import org.graalvm.compiler.nodes.extended.GuardingNode; 39 import org.graalvm.compiler.nodes.extended.IntegerSwitchNode; 40 import org.graalvm.compiler.nodes.spi.StampProvider; 41 import org.graalvm.compiler.nodes.util.GraphUtil; 42 43 import jdk.vm.ci.code.Architecture; 44 import jdk.vm.ci.meta.Assumptions; 45 import jdk.vm.ci.meta.ConstantReflectionProvider; 46 import jdk.vm.ci.meta.MetaAccessProvider; 47 48 /** 49 * Graph decoder that simplifies nodes during decoding. The standard 50 * {@link Canonicalizable#canonical node canonicalization} interface is used to canonicalize nodes 51 * during decoding. Additionally, {@link IfNode branches} and {@link IntegerSwitchNode switches} 52 * with constant conditions are simplified. 53 */ 54 public class SimplifyingGraphDecoder extends GraphDecoder { 55 56 protected final MetaAccessProvider metaAccess; 57 protected final ConstantReflectionProvider constantReflection; 58 protected final ConstantFieldProvider constantFieldProvider; 59 protected final StampProvider stampProvider; 60 protected final boolean canonicalizeReads; 61 62 protected class PECanonicalizerTool implements CanonicalizerTool { 63 64 private final Assumptions assumptions; 65 66 public PECanonicalizerTool(Assumptions assumptions) { 67 this.assumptions = assumptions; 68 } 69 70 @Override 71 public MetaAccessProvider getMetaAccess() { 72 return metaAccess; 73 } 74 75 @Override 76 public ConstantReflectionProvider getConstantReflection() { 77 return constantReflection; 78 } 79 80 @Override 81 public ConstantFieldProvider getConstantFieldProvider() { 82 return constantFieldProvider; 83 } 84 85 @Override 86 public boolean canonicalizeReads() { 87 return canonicalizeReads; 88 } 89 90 @Override 91 public boolean allUsagesAvailable() { 92 return false; 93 } 94 95 @Override 96 public Assumptions getAssumptions() { 97 return assumptions; 98 } 99 100 @Override 101 public boolean supportSubwordCompare(int bits) { 102 // to be safe, just report false here 103 // there will be more opportunities for this optimization later 104 return false; 105 } 106 } 107 108 @NodeInfo(cycles = CYCLES_IGNORED, size = SIZE_IGNORED) 109 static class CanonicalizeToNullNode extends FloatingNode implements Canonicalizable, GuardingNode { 110 public static final NodeClass<CanonicalizeToNullNode> TYPE = NodeClass.create(CanonicalizeToNullNode.class); 111 112 protected CanonicalizeToNullNode(Stamp stamp) { 113 super(TYPE, stamp); 114 } 115 116 @Override 117 public Node canonical(CanonicalizerTool tool) { 118 return null; 119 } 120 } 121 122 public SimplifyingGraphDecoder(MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider, StampProvider stampProvider, 123 boolean canonicalizeReads, Architecture architecture) { 124 super(architecture); 125 this.metaAccess = metaAccess; 126 this.constantReflection = constantReflection; 127 this.constantFieldProvider = constantFieldProvider; 128 this.stampProvider = stampProvider; 129 this.canonicalizeReads = canonicalizeReads; 130 } 131 132 @Override 133 protected void cleanupGraph(MethodScope methodScope) { 134 GraphUtil.normalizeLoops(methodScope.graph); 135 super.cleanupGraph(methodScope); 136 137 for (Node node : methodScope.graph.getNewNodes(methodScope.methodStartMark)) { 138 if (node instanceof MergeNode) { 139 MergeNode mergeNode = (MergeNode) node; 140 if (mergeNode.forwardEndCount() == 1) { 141 methodScope.graph.reduceTrivialMerge(mergeNode); 142 } 143 } 144 } 145 146 for (Node node : methodScope.graph.getNewNodes(methodScope.methodStartMark)) { 147 if (node instanceof BeginNode || node instanceof KillingBeginNode) { 148 if (!(node.predecessor() instanceof ControlSplitNode) && node.hasNoUsages()) { 149 GraphUtil.unlinkFixedNode((AbstractBeginNode) node); 150 node.safeDelete(); 151 } 152 } 153 } 154 155 for (Node node : methodScope.graph.getNewNodes(methodScope.methodStartMark)) { 156 GraphUtil.tryKillUnused(node); 157 } 158 } 159 160 @Override 161 protected boolean allowLazyPhis() { 162 /* 163 * We do not need to exactly reproduce the encoded graph, so we want to avoid unnecessary 164 * phi functions. 165 */ 166 return true; 167 } 168 169 @Override 170 protected void handleMergeNode(MergeNode merge) { 171 /* 172 * All inputs of non-loop phi nodes are known by now. We can infer the stamp for the phi, so 173 * that parsing continues with more precise type information. 174 */ 175 for (ValuePhiNode phi : merge.valuePhis()) { 176 phi.inferStamp(); 177 } 178 } 179 180 @Override 181 protected void handleFixedNode(MethodScope methodScope, LoopScope loopScope, int nodeOrderId, FixedNode node) { 182 if (node instanceof IfNode) { 183 IfNode ifNode = (IfNode) node; 184 if (ifNode.condition() instanceof LogicNegationNode) { 185 ifNode.eliminateNegation(); 186 } 187 if (ifNode.condition() instanceof LogicConstantNode) { 188 boolean condition = ((LogicConstantNode) ifNode.condition()).getValue(); 189 AbstractBeginNode survivingSuccessor = ifNode.getSuccessor(condition); 190 AbstractBeginNode deadSuccessor = ifNode.getSuccessor(!condition); 191 192 methodScope.graph.removeSplit(ifNode, survivingSuccessor); 193 assert deadSuccessor.next() == null : "must not be parsed yet"; 194 deadSuccessor.safeDelete(); 195 } 196 197 } else if (node instanceof IntegerSwitchNode && ((IntegerSwitchNode) node).value().isConstant()) { 198 IntegerSwitchNode switchNode = (IntegerSwitchNode) node; 199 int value = switchNode.value().asJavaConstant().asInt(); 200 AbstractBeginNode survivingSuccessor = switchNode.successorAtKey(value); 201 List<Node> allSuccessors = switchNode.successors().snapshot(); 202 203 methodScope.graph.removeSplit(switchNode, survivingSuccessor); 204 for (Node successor : allSuccessors) { 205 if (successor != survivingSuccessor) { 206 assert ((AbstractBeginNode) successor).next() == null : "must not be parsed yet"; 207 successor.safeDelete(); 208 } 209 } 210 211 } else if (node instanceof FixedGuardNode) { 212 FixedGuardNode guard = (FixedGuardNode) node; 213 if (guard.getCondition() instanceof LogicConstantNode) { 214 LogicConstantNode condition = (LogicConstantNode) guard.getCondition(); 215 Node canonical; 216 if (condition.getValue() == guard.isNegated()) { 217 DeoptimizeNode deopt = new DeoptimizeNode(guard.getAction(), guard.getReason(), guard.getSpeculation()); 218 if (guard.stateBefore() != null) { 219 deopt.setStateBefore(guard.stateBefore()); 220 } 221 canonical = deopt; 222 } else { 223 /* 224 * The guard is unnecessary, but we cannot remove the node completely yet 225 * because there might be nodes that use it as a guard input. Therefore, we 226 * replace it with a more lightweight node (which is floating and has no 227 * inputs). 228 */ 229 canonical = new CanonicalizeToNullNode(node.stamp); 230 } 231 handleCanonicalization(methodScope, loopScope, nodeOrderId, node, canonical); 232 } 233 234 } else if (node instanceof Canonicalizable) { 235 Node canonical = ((Canonicalizable) node).canonical(new PECanonicalizerTool(methodScope.graph.getAssumptions())); 236 if (canonical != node) { 237 handleCanonicalization(methodScope, loopScope, nodeOrderId, node, canonical); 238 } 239 } 240 } 241 242 private void handleCanonicalization(MethodScope methodScope, LoopScope loopScope, int nodeOrderId, FixedNode node, Node c) { 243 Node canonical = c; 244 245 if (canonical == null) { 246 /* 247 * This is a possible return value of canonicalization. However, we might need to add 248 * additional usages later on for which we need a node. Therefore, we just do nothing 249 * and leave the node in place. 250 */ 251 return; 252 } 253 254 if (!canonical.isAlive()) { 255 assert !canonical.isDeleted(); 256 canonical = methodScope.graph.addOrUniqueWithInputs(canonical); 257 if (canonical instanceof FixedWithNextNode) { 258 methodScope.graph.addBeforeFixed(node, (FixedWithNextNode) canonical); 259 } else if (canonical instanceof ControlSinkNode) { 260 FixedWithNextNode predecessor = (FixedWithNextNode) node.predecessor(); 261 predecessor.setNext((ControlSinkNode) canonical); 262 List<Node> successorSnapshot = node.successors().snapshot(); 263 node.safeDelete(); 264 for (Node successor : successorSnapshot) { 265 successor.safeDelete(); 266 } 267 268 } else { 269 assert !(canonical instanceof FixedNode); 270 } 271 } 272 if (!node.isDeleted()) { 273 GraphUtil.unlinkFixedNode((FixedWithNextNode) node); 274 node.replaceAtUsagesAndDelete(canonical); 275 } 276 assert lookupNode(loopScope, nodeOrderId) == node; 277 registerNode(loopScope, nodeOrderId, canonical, true, false); 278 } 279 280 @Override 281 protected Node handleFloatingNodeBeforeAdd(MethodScope methodScope, LoopScope loopScope, Node node) { 282 if (node instanceof ValueNode) { 283 ((ValueNode) node).inferStamp(); 284 } 285 if (node instanceof Canonicalizable) { 286 Node canonical = ((Canonicalizable) node).canonical(new PECanonicalizerTool(methodScope.graph.getAssumptions())); 287 if (canonical == null) { 288 /* 289 * This is a possible return value of canonicalization. However, we might need to 290 * add additional usages later on for which we need a node. Therefore, we just do 291 * nothing and leave the node in place. 292 */ 293 } else if (canonical != node) { 294 if (!canonical.isAlive()) { 295 assert !canonical.isDeleted(); 296 canonical = methodScope.graph.addOrUniqueWithInputs(canonical); 297 } 298 assert node.hasNoUsages(); 299 // methodScope.graph.replaceFloating((FloatingNode) node, canonical); 300 return canonical; 301 } 302 } 303 return node; 304 } 305 306 @Override 307 protected Node addFloatingNode(MethodScope methodScope, Node node) { 308 /* 309 * In contrast to the base class implementation, we do not need to exactly reproduce the 310 * encoded graph. Since we do canonicalization, we also want nodes to be unique. 311 */ 312 return methodScope.graph.addOrUnique(node); 313 } 314 }