Mercurial > hg > graal-compiler
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java @ 20110:51f2e71b57aa
Improvements to the Stamp infrastructure. New methods Stamp#improveWith, Stamp#tryImproveWith, Stamp#isIllegal.
author | Thomas Wuerthinger <thomas.wuerthinger@oracle.com> |
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date | Wed, 01 Apr 2015 16:36:15 +0200 |
parents | deab43a789ad |
children | 343021aacd2f |
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/* * Copyright (c) 2009, 2014, 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 com.oracle.graal.nodes.java; import static com.oracle.graal.api.meta.DeoptimizationAction.*; import static com.oracle.graal.api.meta.DeoptimizationReason.*; import static com.oracle.graal.nodes.extended.BranchProbabilityNode.*; import com.oracle.graal.api.meta.*; import com.oracle.graal.api.meta.Assumptions.AssumptionResult; import com.oracle.graal.compiler.common.type.*; import com.oracle.graal.graph.*; import com.oracle.graal.graph.spi.*; import com.oracle.graal.nodeinfo.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.calc.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.nodes.type.*; /** * Implements a type check against a compile-time known type. */ @NodeInfo public final class CheckCastNode extends FixedWithNextNode implements Canonicalizable, Simplifiable, Lowerable, Virtualizable, ValueProxy { public static final NodeClass<CheckCastNode> TYPE = NodeClass.create(CheckCastNode.class); @Input protected ValueNode object; protected final ResolvedJavaType type; protected final JavaTypeProfile profile; /** * Determines the exception thrown by this node if the check fails: {@link ClassCastException} * if false; {@link ArrayStoreException} if true. */ protected final boolean forStoreCheck; public CheckCastNode(ResolvedJavaType type, ValueNode object, JavaTypeProfile profile, boolean forStoreCheck) { super(TYPE, StampFactory.declaredTrusted(type)); assert object.stamp() instanceof ObjectStamp : object + ":" + object.stamp(); assert type != null; this.type = type; this.object = object; this.profile = profile; this.forStoreCheck = forStoreCheck; } public static ValueNode create(ResolvedJavaType inputType, ValueNode object, JavaTypeProfile profile, boolean forStoreCheck, Assumptions assumptions) { ResolvedJavaType type = inputType; ValueNode synonym = findSynonym(type, object); if (synonym != null) { return synonym; } assert object.stamp() instanceof ObjectStamp : object + ":" + object.stamp(); if (assumptions != null) { AssumptionResult<ResolvedJavaType> leafConcreteSubtype = type.findLeafConcreteSubtype(); if (leafConcreteSubtype != null && !leafConcreteSubtype.getResult().equals(type)) { assumptions.record(leafConcreteSubtype); type = leafConcreteSubtype.getResult(); } } return new CheckCastNode(type, object, profile, forStoreCheck); } public boolean isForStoreCheck() { return forStoreCheck; } /** * Lowers a {@link CheckCastNode} to a {@link GuardingPiNode}. That is: * * <pre> * 1: A a = ... * 2: B b = (B) a; * </pre> * * is lowered to: * * <pre> * 1: A a = ... * 2: B b = guardingPi(a == null || a instanceof B, a, stamp(B)) * </pre> * * or if a is known to be non-null: * * <pre> * 1: A a = ... * 2: B b = guardingPi(a instanceof B, a, stamp(B, non-null)) * </pre> * * Note: we use {@link Graph#addWithoutUnique} as opposed to {@link Graph#unique} for the new * {@link InstanceOfNode} to maintain the invariant checked by * {@code LoweringPhase.checkUsagesAreScheduled()}. */ @Override public void lower(LoweringTool tool) { Stamp newStamp = StampFactory.declaredTrusted(type).improveWith(object().stamp()); ValueNode condition; ValueNode theValue = object; if (newStamp instanceof IllegalStamp) { // This is a check cast that will always fail condition = LogicConstantNode.contradiction(graph()); newStamp = StampFactory.declaredTrusted(type); } else if (StampTool.isPointerNonNull(object)) { condition = graph().addWithoutUnique(new InstanceOfNode(type, object, profile)); } else { if (profile != null && profile.getNullSeen() == TriState.FALSE) { FixedGuardNode nullCheck = graph().add(new FixedGuardNode(graph().unique(new IsNullNode(object)), UnreachedCode, InvalidateReprofile, true)); PiNode nullGuarded = graph().unique(new PiNode(object, object().stamp().join(StampFactory.objectNonNull()), nullCheck)); InstanceOfNode typeTest = graph().addWithoutUnique(new InstanceOfNode(type, nullGuarded, profile)); graph().addBeforeFixed(this, nullCheck); condition = typeTest; /* * The PiNode is injecting an extra guard into the type so make sure it's used in * the GuardingPi, otherwise we can lose the null guard if the InstanceOf is * optimized away. */ theValue = nullGuarded; newStamp = newStamp.join(StampFactory.objectNonNull()); nullCheck.lower(tool); } else { // TODO (ds) replace with probability of null-seen when available double shortCircuitProbability = NOT_FREQUENT_PROBABILITY; InstanceOfNode typeTest = graph().addWithoutUnique(new InstanceOfNode(type, object, profile)); condition = LogicNode.or(graph().unique(new IsNullNode(object)), typeTest, shortCircuitProbability); } } GuardingPiNode checkedObject = graph().add(new GuardingPiNode(theValue, condition, false, forStoreCheck ? ArrayStoreException : ClassCastException, InvalidateReprofile, newStamp)); graph().replaceFixedWithFixed(this, checkedObject); checkedObject.lower(tool); } @Override public boolean inferStamp() { if (object().stamp() instanceof ObjectStamp) { ObjectStamp castStamp = (ObjectStamp) StampFactory.declaredTrusted(type); return updateStamp(castStamp.improveWith(object().stamp())); } return false; } @Override public Node canonical(CanonicalizerTool tool) { ValueNode synonym = findSynonym(type, object()); if (synonym != null) { return synonym; } Assumptions assumptions = graph().getAssumptions(); if (assumptions != null) { AssumptionResult<ResolvedJavaType> leafConcreteSubtype = type.findLeafConcreteSubtype(); if (leafConcreteSubtype != null && !leafConcreteSubtype.getResult().equals(type)) { // Propagate more precise type information to usages of the checkcast. assumptions.record(leafConcreteSubtype); return new CheckCastNode(leafConcreteSubtype.getResult(), object, profile, forStoreCheck); } } return this; } private static ValueNode findSynonym(ResolvedJavaType type, ValueNode object) { ResolvedJavaType objectType = StampTool.typeOrNull(object); if (objectType != null && type.isAssignableFrom(objectType)) { // we don't have to check for null types here because they will also pass the // checkcast. return object; } if (StampTool.isPointerAlwaysNull(object)) { return object; } return null; } @Override public void simplify(SimplifierTool tool) { // if the previous node is also a checkcast, with a less precise and compatible type, // replace both with one checkcast checking the more specific type. if (predecessor() instanceof CheckCastNode) { CheckCastNode ccn = (CheckCastNode) predecessor(); if (ccn != null && ccn.type != null && ccn == object && ccn.forStoreCheck == forStoreCheck && ccn.type.isAssignableFrom(type)) { StructuredGraph graph = ccn.graph(); CheckCastNode newccn = graph.add(new CheckCastNode(type, ccn.object, ccn.profile, ccn.forStoreCheck)); graph.replaceFixedWithFixed(ccn, newccn); replaceAtUsages(newccn); graph.removeFixed(this); } } } public ValueNode object() { return object; } /** * Gets the type being cast to. */ public ResolvedJavaType type() { return type; } public JavaTypeProfile profile() { return profile; } @Override public void virtualize(VirtualizerTool tool) { State state = tool.getObjectState(object); if (state != null && state.getState() == EscapeState.Virtual) { if (type.isAssignableFrom(state.getVirtualObject().type())) { tool.replaceWithVirtual(state.getVirtualObject()); } } } @Override public ValueNode getOriginalNode() { return object; } public TriState tryFold(Stamp testStamp) { if (testStamp instanceof ObjectStamp) { ObjectStamp objectStamp = (ObjectStamp) testStamp; ResolvedJavaType objectType = objectStamp.type(); if (objectType != null && type.isAssignableFrom(objectType)) { return TriState.TRUE; } else if (objectStamp.alwaysNull()) { return TriState.TRUE; } } return TriState.UNKNOWN; } }