hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.phases.common/src/org/graalvm/compiler/phases/common/UseTrappingNullChecksPhase.java
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.phases.common/src/org/graalvm/compiler/phases/common/UseTrappingNullChecksPhase.java Thu Feb 16 15:46:09 2017 -0800
@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2014, 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 org.graalvm.compiler.phases.common;
+
+import java.util.List;
+
+import org.graalvm.compiler.debug.Debug;
+import org.graalvm.compiler.debug.DebugCounter;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.nodeinfo.InputType;
+import org.graalvm.compiler.nodes.AbstractBeginNode;
+import org.graalvm.compiler.nodes.AbstractDeoptimizeNode;
+import org.graalvm.compiler.nodes.AbstractEndNode;
+import org.graalvm.compiler.nodes.AbstractMergeNode;
+import org.graalvm.compiler.nodes.BeginNode;
+import org.graalvm.compiler.nodes.DeoptimizeNode;
+import org.graalvm.compiler.nodes.DynamicDeoptimizeNode;
+import org.graalvm.compiler.nodes.FixedNode;
+import org.graalvm.compiler.nodes.IfNode;
+import org.graalvm.compiler.nodes.LogicNode;
+import org.graalvm.compiler.nodes.StructuredGraph;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.ValuePhiNode;
+import org.graalvm.compiler.nodes.calc.IsNullNode;
+import org.graalvm.compiler.nodes.extended.NullCheckNode;
+import org.graalvm.compiler.nodes.util.GraphUtil;
+import org.graalvm.compiler.phases.BasePhase;
+import org.graalvm.compiler.phases.tiers.LowTierContext;
+
+import jdk.vm.ci.meta.DeoptimizationReason;
+import jdk.vm.ci.meta.JavaConstant;
+import jdk.vm.ci.meta.MetaAccessProvider;
+
+public class UseTrappingNullChecksPhase extends BasePhase<LowTierContext> {
+
+ private static final DebugCounter counterTrappingNullCheck = Debug.counter("TrappingNullCheck");
+ private static final DebugCounter counterTrappingNullCheckUnreached = Debug.counter("TrappingNullCheckUnreached");
+ private static final DebugCounter counterTrappingNullCheckDynamicDeoptimize = Debug.counter("TrappingNullCheckDynamicDeoptimize");
+
+ @Override
+ protected void run(StructuredGraph graph, LowTierContext context) {
+ if (context.getTarget().implicitNullCheckLimit <= 0) {
+ return;
+ }
+ assert graph.getGuardsStage().areFrameStatesAtDeopts();
+
+ for (DeoptimizeNode deopt : graph.getNodes(DeoptimizeNode.TYPE)) {
+ tryUseTrappingNullCheck(deopt, deopt.predecessor(), deopt.reason(), deopt.getSpeculation());
+ }
+ for (DynamicDeoptimizeNode deopt : graph.getNodes(DynamicDeoptimizeNode.TYPE)) {
+ tryUseTrappingNullCheck(context.getMetaAccess(), deopt);
+ }
+ }
+
+ private static void tryUseTrappingNullCheck(MetaAccessProvider metaAccessProvider, DynamicDeoptimizeNode deopt) {
+ Node predecessor = deopt.predecessor();
+ if (predecessor instanceof AbstractMergeNode) {
+ AbstractMergeNode merge = (AbstractMergeNode) predecessor;
+
+ // Process each predecessor at the merge, unpacking the reasons and speculations as
+ // needed.
+ ValueNode reason = deopt.getActionAndReason();
+ ValuePhiNode reasonPhi = null;
+ List<ValueNode> reasons = null;
+ int expectedPhis = 0;
+
+ if (reason instanceof ValuePhiNode) {
+ reasonPhi = (ValuePhiNode) reason;
+ if (reasonPhi.merge() != merge) {
+ return;
+ }
+ reasons = reasonPhi.values().snapshot();
+ expectedPhis++;
+ } else if (!reason.isConstant()) {
+ return;
+ }
+
+ ValueNode speculation = deopt.getSpeculation();
+ ValuePhiNode speculationPhi = null;
+ List<ValueNode> speculations = null;
+ if (speculation instanceof ValuePhiNode) {
+ speculationPhi = (ValuePhiNode) speculation;
+ if (speculationPhi.merge() != merge) {
+ return;
+ }
+ speculations = speculationPhi.values().snapshot();
+ expectedPhis++;
+ }
+
+ if (merge.phis().count() != expectedPhis) {
+ return;
+ }
+
+ int index = 0;
+ for (AbstractEndNode end : merge.cfgPredecessors().snapshot()) {
+ ValueNode thisReason = reasons != null ? reasons.get(index) : reason;
+ ValueNode thisSpeculation = speculations != null ? speculations.get(index++) : speculation;
+ if (!thisReason.isConstant() || !thisSpeculation.isConstant() || !thisSpeculation.asConstant().equals(JavaConstant.NULL_POINTER)) {
+ continue;
+ }
+ DeoptimizationReason deoptimizationReason = metaAccessProvider.decodeDeoptReason(thisReason.asJavaConstant());
+ tryUseTrappingNullCheck(deopt, end.predecessor(), deoptimizationReason, null);
+ }
+ }
+ }
+
+ private static void tryUseTrappingNullCheck(AbstractDeoptimizeNode deopt, Node predecessor, DeoptimizationReason deoptimizationReason, JavaConstant speculation) {
+ if (deoptimizationReason != DeoptimizationReason.NullCheckException && deoptimizationReason != DeoptimizationReason.UnreachedCode) {
+ return;
+ }
+ if (speculation != null && !speculation.equals(JavaConstant.NULL_POINTER)) {
+ return;
+ }
+ if (predecessor instanceof AbstractMergeNode) {
+ AbstractMergeNode merge = (AbstractMergeNode) predecessor;
+ if (merge.phis().isEmpty()) {
+ for (AbstractEndNode end : merge.cfgPredecessors().snapshot()) {
+ checkPredecessor(deopt, end.predecessor(), deoptimizationReason);
+ }
+ }
+ } else if (predecessor instanceof AbstractBeginNode) {
+ checkPredecessor(deopt, predecessor, deoptimizationReason);
+ }
+ }
+
+ private static void checkPredecessor(AbstractDeoptimizeNode deopt, Node predecessor, DeoptimizationReason deoptimizationReason) {
+ Node current = predecessor;
+ AbstractBeginNode branch = null;
+ while (current instanceof AbstractBeginNode) {
+ branch = (AbstractBeginNode) current;
+ if (branch.anchored().isNotEmpty()) {
+ // some input of the deopt framestate is anchored to this branch
+ return;
+ }
+ current = current.predecessor();
+ }
+ if (current instanceof IfNode) {
+ IfNode ifNode = (IfNode) current;
+ if (branch != ifNode.trueSuccessor()) {
+ return;
+ }
+ LogicNode condition = ifNode.condition();
+ if (condition instanceof IsNullNode) {
+ replaceWithTrappingNullCheck(deopt, ifNode, condition, deoptimizationReason);
+ }
+ }
+ }
+
+ private static void replaceWithTrappingNullCheck(AbstractDeoptimizeNode deopt, IfNode ifNode, LogicNode condition, DeoptimizationReason deoptimizationReason) {
+ counterTrappingNullCheck.increment();
+ if (deopt instanceof DynamicDeoptimizeNode) {
+ counterTrappingNullCheckDynamicDeoptimize.increment();
+ }
+ if (deoptimizationReason == DeoptimizationReason.UnreachedCode) {
+ counterTrappingNullCheckUnreached.increment();
+ }
+ IsNullNode isNullNode = (IsNullNode) condition;
+ AbstractBeginNode nonTrappingContinuation = ifNode.falseSuccessor();
+ AbstractBeginNode trappingContinuation = ifNode.trueSuccessor();
+ NullCheckNode trappingNullCheck = deopt.graph().add(new NullCheckNode(isNullNode.getValue()));
+ trappingNullCheck.setStateBefore(deopt.stateBefore());
+ deopt.graph().replaceSplit(ifNode, trappingNullCheck, nonTrappingContinuation);
+
+ /*
+ * We now have the pattern NullCheck/BeginNode/... It's possible some node is using the
+ * BeginNode as a guard input, so replace guard users of the Begin with the NullCheck and
+ * then remove the Begin from the graph.
+ */
+ nonTrappingContinuation.replaceAtUsages(InputType.Guard, trappingNullCheck);
+ if (nonTrappingContinuation instanceof BeginNode) {
+ FixedNode next = nonTrappingContinuation.next();
+ nonTrappingContinuation.clearSuccessors();
+ trappingNullCheck.setNext(next);
+ nonTrappingContinuation.safeDelete();
+ } else {
+ trappingNullCheck.setNext(nonTrappingContinuation);
+ }
+
+ GraphUtil.killCFG(trappingContinuation);
+ GraphUtil.tryKillUnused(isNullNode);
+ }
+}