/*
 * Copyright (c) 2014, 2016, 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
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package org.graalvm.compiler.replacements.aarch64;

import org.graalvm.compiler.api.replacements.Snippet;
import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.Node.NodeIntrinsic;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.DeoptimizeNode;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.FixedBinaryNode;
import org.graalvm.compiler.nodes.calc.SignedDivNode;
import org.graalvm.compiler.nodes.calc.SignedRemNode;
import org.graalvm.compiler.nodes.calc.UnsignedDivNode;
import org.graalvm.compiler.nodes.calc.UnsignedRemNode;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.phases.util.Providers;
import org.graalvm.compiler.replacements.SnippetTemplate;
import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
import org.graalvm.compiler.replacements.Snippets;

import jdk.vm.ci.code.TargetDescription;
import jdk.vm.ci.meta.DeoptimizationAction;
import jdk.vm.ci.meta.DeoptimizationReason;
import jdk.vm.ci.meta.JavaKind;

Division in AArch64 ISA does not generate a trap when dividing by zero, but instead sets the result to 0. These snippets throw an ArithmethicException if the denominator is 0 and otherwise forward to the LIRGenerator.
/** * Division in AArch64 ISA does not generate a trap when dividing by zero, but instead sets the * result to 0. These snippets throw an ArithmethicException if the denominator is 0 and otherwise * forward to the LIRGenerator. */
public class AArch64IntegerArithmeticSnippets extends AbstractTemplates implements Snippets { private final SnippetTemplate.SnippetInfo idiv; private final SnippetTemplate.SnippetInfo ldiv; private final SnippetTemplate.SnippetInfo irem; private final SnippetTemplate.SnippetInfo lrem; private final SnippetTemplate.SnippetInfo uidiv; private final SnippetTemplate.SnippetInfo uldiv; private final SnippetTemplate.SnippetInfo uirem; private final SnippetTemplate.SnippetInfo ulrem; public AArch64IntegerArithmeticSnippets(Providers providers, SnippetReflectionProvider snippetReflection, TargetDescription target) { super(providers, snippetReflection, target); idiv = snippet(AArch64IntegerArithmeticSnippets.class, "idivSnippet"); ldiv = snippet(AArch64IntegerArithmeticSnippets.class, "ldivSnippet"); irem = snippet(AArch64IntegerArithmeticSnippets.class, "iremSnippet"); lrem = snippet(AArch64IntegerArithmeticSnippets.class, "lremSnippet"); uidiv = snippet(AArch64IntegerArithmeticSnippets.class, "uidivSnippet"); uldiv = snippet(AArch64IntegerArithmeticSnippets.class, "uldivSnippet"); uirem = snippet(AArch64IntegerArithmeticSnippets.class, "uiremSnippet"); ulrem = snippet(AArch64IntegerArithmeticSnippets.class, "ulremSnippet"); } public void lower(FixedBinaryNode node, LoweringTool tool) { JavaKind kind = node.stamp().getStackKind(); assert kind == JavaKind.Int || kind == JavaKind.Long; SnippetTemplate.SnippetInfo snippet; if (node instanceof SafeNode) { // We already introduced the zero division check, nothing to do. return; } else if (node instanceof SignedDivNode) { snippet = kind == JavaKind.Int ? idiv : ldiv; } else if (node instanceof SignedRemNode) { snippet = kind == JavaKind.Int ? irem : lrem; } else if (node instanceof UnsignedDivNode) { snippet = kind == JavaKind.Int ? uidiv : uldiv; } else if (node instanceof UnsignedRemNode) { snippet = kind == JavaKind.Int ? uirem : ulrem; } else { throw GraalError.shouldNotReachHere(); } StructuredGraph graph = node.graph(); Arguments args = new Arguments(snippet, graph.getGuardsStage(), tool.getLoweringStage()); args.add("x", node.getX()); args.add("y", node.getY()); template(args).instantiate(providers.getMetaAccess(), node, SnippetTemplate.DEFAULT_REPLACER, args); } @Snippet public static int idivSnippet(int x, int y) { checkForZero(y); return safeDiv(x, y); } @Snippet public static long ldivSnippet(long x, long y) { checkForZero(y); return safeDiv(x, y); } @Snippet public static int iremSnippet(int x, int y) { checkForZero(y); return safeRem(x, y); } @Snippet public static long lremSnippet(long x, long y) { checkForZero(y); return safeRem(x, y); } @Snippet public static int uidivSnippet(int x, int y) { checkForZero(y); return safeUDiv(x, y); } @Snippet public static long uldivSnippet(long x, long y) { checkForZero(y); return safeUDiv(x, y); } @Snippet public static int uiremSnippet(int x, int y) { checkForZero(y); return safeURem(x, y); } @Snippet public static long ulremSnippet(long x, long y) { checkForZero(y); return safeURem(x, y); } private static void checkForZero(int y) { if (y == 0) { // "/ by zero" DeoptimizeNode.deopt(DeoptimizationAction.None, DeoptimizationReason.ArithmeticException); } } private static void checkForZero(long y) { if (y == 0) { // "/ by zero" DeoptimizeNode.deopt(DeoptimizationAction.None, DeoptimizationReason.ArithmeticException); } } @NodeIntrinsic(SafeSignedDivNode.class) private static native int safeDiv(int x, int y); @NodeIntrinsic(SafeSignedDivNode.class) private static native long safeDiv(long x, long y); @NodeIntrinsic(SafeSignedRemNode.class) private static native int safeRem(int x, int y); @NodeIntrinsic(SafeSignedRemNode.class) private static native long safeRem(long x, long y); @NodeIntrinsic(SafeUnsignedDivNode.class) private static native int safeUDiv(int x, int y); @NodeIntrinsic(SafeUnsignedDivNode.class) private static native long safeUDiv(long x, long y); @NodeIntrinsic(SafeUnsignedRemNode.class) private static native int safeURem(int x, int y); @NodeIntrinsic(SafeUnsignedRemNode.class) private static native long safeURem(long x, long y);
Marker interface to distinguish untreated nodes from ones where we have installed the additional checks.
/** * Marker interface to distinguish untreated nodes from ones where we have installed the * additional checks. */
private interface SafeNode { } @NodeInfo static class SafeSignedDivNode extends SignedDivNode implements SafeNode { public static final NodeClass<SafeSignedDivNode> TYPE = NodeClass.create(SafeSignedDivNode.class); protected SafeSignedDivNode(ValueNode x, ValueNode y) { super(TYPE, x, y); } } @NodeInfo static class SafeSignedRemNode extends SignedRemNode implements SafeNode { public static final NodeClass<SafeSignedRemNode> TYPE = NodeClass.create(SafeSignedRemNode.class); protected SafeSignedRemNode(ValueNode x, ValueNode y) { super(TYPE, x, y); } } @NodeInfo static class SafeUnsignedDivNode extends UnsignedDivNode implements SafeNode { public static final NodeClass<SafeUnsignedDivNode> TYPE = NodeClass.create(SafeUnsignedDivNode.class); protected SafeUnsignedDivNode(ValueNode x, ValueNode y) { super(TYPE, x, y); } } @NodeInfo static class SafeUnsignedRemNode extends UnsignedRemNode implements SafeNode { public static final NodeClass<SafeUnsignedRemNode> TYPE = NodeClass.create(SafeUnsignedRemNode.class); protected SafeUnsignedRemNode(ValueNode x, ValueNode y) { super(TYPE, x, y); } } }