/*
 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package org.graalvm.compiler.nodes;

import static org.graalvm.compiler.nodeinfo.InputType.Guard;
import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_IGNORED;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_IGNORED;

import java.util.List;

import org.graalvm.compiler.core.common.spi.ConstantFieldProvider;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.debug.DebugCloseable;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.spi.Canonicalizable;
import org.graalvm.compiler.graph.spi.CanonicalizerTool;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.calc.FloatingNode;
import org.graalvm.compiler.nodes.extended.GuardingNode;
import org.graalvm.compiler.nodes.extended.IntegerSwitchNode;
import org.graalvm.compiler.nodes.java.ArrayLengthNode;
import org.graalvm.compiler.nodes.java.LoadFieldNode;
import org.graalvm.compiler.nodes.java.LoadIndexedNode;
import org.graalvm.compiler.nodes.spi.StampProvider;
import org.graalvm.compiler.nodes.util.GraphUtil;
import org.graalvm.compiler.options.OptionValues;

import jdk.vm.ci.code.Architecture;
import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.ConstantReflectionProvider;
import jdk.vm.ci.meta.MetaAccessProvider;

Graph decoder that simplifies nodes during decoding. The standard node canonicalization interface is used to canonicalize nodes during decoding. Additionally, branches and switches with constant conditions are simplified.
/** * Graph decoder that simplifies nodes during decoding. The standard * {@link Canonicalizable#canonical node canonicalization} interface is used to canonicalize nodes * during decoding. Additionally, {@link IfNode branches} and {@link IntegerSwitchNode switches} * with constant conditions are simplified. */
public class SimplifyingGraphDecoder extends GraphDecoder { protected final MetaAccessProvider metaAccess; protected final ConstantReflectionProvider constantReflection; protected final ConstantFieldProvider constantFieldProvider; protected final StampProvider stampProvider; protected final boolean canonicalizeReads; protected final CanonicalizerTool canonicalizerTool; protected class PECanonicalizerTool implements CanonicalizerTool { private final Assumptions assumptions; private final OptionValues options; public PECanonicalizerTool(Assumptions assumptions, OptionValues options) { this.assumptions = assumptions; this.options = options; } @Override public OptionValues getOptions() { return options; } @Override public MetaAccessProvider getMetaAccess() { return metaAccess; } @Override public ConstantReflectionProvider getConstantReflection() { return constantReflection; } @Override public ConstantFieldProvider getConstantFieldProvider() { return constantFieldProvider; } @Override public boolean canonicalizeReads() { return canonicalizeReads; } @Override public boolean allUsagesAvailable() { return false; } @Override public Assumptions getAssumptions() { return assumptions; } @Override public Integer smallestCompareWidth() { // to be safe, just report null here // there will be more opportunities for this optimization later return null; } } @NodeInfo(cycles = CYCLES_IGNORED, size = SIZE_IGNORED, allowedUsageTypes = {Guard}) static class CanonicalizeToNullNode extends FloatingNode implements Canonicalizable, GuardingNode { public static final NodeClass<CanonicalizeToNullNode> TYPE = NodeClass.create(CanonicalizeToNullNode.class); protected CanonicalizeToNullNode(Stamp stamp) { super(TYPE, stamp); } @Override public Node canonical(CanonicalizerTool tool) { return null; } } public SimplifyingGraphDecoder(Architecture architecture, StructuredGraph graph, MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection, ConstantFieldProvider constantFieldProvider, StampProvider stampProvider, boolean canonicalizeReads) { super(architecture, graph); this.metaAccess = metaAccess; this.constantReflection = constantReflection; this.constantFieldProvider = constantFieldProvider; this.stampProvider = stampProvider; this.canonicalizeReads = canonicalizeReads; this.canonicalizerTool = new PECanonicalizerTool(graph.getAssumptions(), graph.getOptions()); } @Override protected void cleanupGraph(MethodScope methodScope) { GraphUtil.normalizeLoops(graph); super.cleanupGraph(methodScope); for (Node node : graph.getNewNodes(methodScope.methodStartMark)) { if (node instanceof MergeNode) { MergeNode mergeNode = (MergeNode) node; if (mergeNode.forwardEndCount() == 1) { graph.reduceTrivialMerge(mergeNode); } } else if (node instanceof BeginNode || node instanceof KillingBeginNode) { if (!(node.predecessor() instanceof ControlSplitNode) && node.hasNoUsages()) { GraphUtil.unlinkFixedNode((AbstractBeginNode) node); node.safeDelete(); } } } for (Node node : graph.getNewNodes(methodScope.methodStartMark)) { GraphUtil.tryKillUnused(node); } } @Override protected boolean allowLazyPhis() { /* * We do not need to exactly reproduce the encoded graph, so we want to avoid unnecessary * phi functions. */ return true; } @Override protected void handleMergeNode(MergeNode merge) { /* * All inputs of non-loop phi nodes are known by now. We can infer the stamp for the phi, so * that parsing continues with more precise type information. */ for (ValuePhiNode phi : merge.valuePhis()) { phi.inferStamp(); } } @Override protected void handleFixedNode(MethodScope methodScope, LoopScope loopScope, int nodeOrderId, FixedNode node) { Node canonical = canonicalizeFixedNode(methodScope, node); if (canonical != node) { handleCanonicalization(loopScope, nodeOrderId, node, canonical); } }
Canonicalizes the provided node, which was originally a FixedNode but can already be canonicalized (and therefore be a non-fixed node).
Params:
  • methodScope – The current method.
  • node – The node to be canonicalized.
/** * Canonicalizes the provided node, which was originally a {@link FixedNode} but can already be * canonicalized (and therefore be a non-fixed node). * * @param methodScope The current method. * @param node The node to be canonicalized. */
protected Node canonicalizeFixedNode(MethodScope methodScope, Node node) { if (node instanceof LoadFieldNode) { LoadFieldNode loadFieldNode = (LoadFieldNode) node; return loadFieldNode.canonical(canonicalizerTool); } else if (node instanceof FixedGuardNode) { FixedGuardNode guard = (FixedGuardNode) node; if (guard.getCondition() instanceof LogicConstantNode) { LogicConstantNode condition = (LogicConstantNode) guard.getCondition(); if (condition.getValue() == guard.isNegated()) { DeoptimizeNode deopt = new DeoptimizeNode(guard.getAction(), guard.getReason(), guard.getSpeculation()); if (guard.stateBefore() != null) { deopt.setStateBefore(guard.stateBefore()); } return deopt; } else { return null; } } return node; } else if (node instanceof IfNode) { IfNode ifNode = (IfNode) node; if (ifNode.condition() instanceof LogicNegationNode) { ifNode.eliminateNegation(); } if (ifNode.condition() instanceof LogicConstantNode) { boolean condition = ((LogicConstantNode) ifNode.condition()).getValue(); AbstractBeginNode survivingSuccessor = ifNode.getSuccessor(condition); AbstractBeginNode deadSuccessor = ifNode.getSuccessor(!condition); graph.removeSplit(ifNode, survivingSuccessor); assert deadSuccessor.next() == null : "must not be parsed yet"; deadSuccessor.safeDelete(); } return node; } else if (node instanceof LoadIndexedNode) { LoadIndexedNode loadIndexedNode = (LoadIndexedNode) node; return loadIndexedNode.canonical(canonicalizerTool); } else if (node instanceof ArrayLengthNode) { ArrayLengthNode arrayLengthNode = (ArrayLengthNode) node; return arrayLengthNode.canonical(canonicalizerTool); } else if (node instanceof IntegerSwitchNode && ((IntegerSwitchNode) node).value().isConstant()) { IntegerSwitchNode switchNode = (IntegerSwitchNode) node; int value = switchNode.value().asJavaConstant().asInt(); AbstractBeginNode survivingSuccessor = switchNode.successorAtKey(value); List<Node> allSuccessors = switchNode.successors().snapshot(); graph.removeSplit(switchNode, survivingSuccessor); for (Node successor : allSuccessors) { if (successor != survivingSuccessor) { assert ((AbstractBeginNode) successor).next() == null : "must not be parsed yet"; successor.safeDelete(); } } return node; } else if (node instanceof Canonicalizable) { return ((Canonicalizable) node).canonical(canonicalizerTool); } else { return node; } } private static Node canonicalizeFixedNodeToNull(FixedNode node) { /* * When a node is unnecessary, we must not remove it right away because there might be nodes * that use it as a guard input. Therefore, we replace it with a more lightweight node * (which is floating and has no inputs). */ return new CanonicalizeToNullNode(node.stamp); } @SuppressWarnings("try") private void handleCanonicalization(LoopScope loopScope, int nodeOrderId, FixedNode node, Node c) { assert c != node : "unnecessary call"; try (DebugCloseable position = graph.withNodeSourcePosition(node)) { Node canonical = c == null ? canonicalizeFixedNodeToNull(node) : c; if (!canonical.isAlive()) { assert !canonical.isDeleted(); canonical = graph.addOrUniqueWithInputs(canonical); if (canonical instanceof FixedWithNextNode) { graph.addBeforeFixed(node, (FixedWithNextNode) canonical); } else if (canonical instanceof ControlSinkNode) { FixedWithNextNode predecessor = (FixedWithNextNode) node.predecessor(); predecessor.setNext((ControlSinkNode) canonical); List<Node> successorSnapshot = node.successors().snapshot(); node.safeDelete(); for (Node successor : successorSnapshot) { successor.safeDelete(); } } else { assert !(canonical instanceof FixedNode); } } if (!node.isDeleted()) { GraphUtil.unlinkFixedNode((FixedWithNextNode) node); node.replaceAtUsagesAndDelete(canonical); } assert lookupNode(loopScope, nodeOrderId) == node; registerNode(loopScope, nodeOrderId, canonical, true, false); } } @Override @SuppressWarnings("try") protected Node handleFloatingNodeBeforeAdd(MethodScope methodScope, LoopScope loopScope, Node node) { if (node instanceof ValueNode) { ((ValueNode) node).inferStamp(); } if (node instanceof Canonicalizable) { try (DebugCloseable context = graph.withNodeSourcePosition(node)) { Node canonical = ((Canonicalizable) node).canonical(canonicalizerTool); if (canonical == null) { /* * This is a possible return value of canonicalization. However, we might need * to add additional usages later on for which we need a node. Therefore, we * just do nothing and leave the node in place. */ } else if (canonical != node) { if (!canonical.isAlive()) { assert !canonical.isDeleted(); canonical = graph.addOrUniqueWithInputs(canonical); } assert node.hasNoUsages(); return canonical; } } } return node; } @Override protected Node addFloatingNode(MethodScope methodScope, Node node) { /* * In contrast to the base class implementation, we do not need to exactly reproduce the * encoded graph. Since we do canonicalization, we also want nodes to be unique. */ return graph.addOrUnique(node); } }