/*
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.graalvm.compiler.hotspot.nodes;

import static org.graalvm.compiler.core.common.GraalOptions.GeneratePIC;
import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_2;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_2;

import org.graalvm.compiler.core.common.type.AbstractObjectStamp;
import org.graalvm.compiler.core.common.type.ObjectStamp;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.spi.CanonicalizerTool;
import org.graalvm.compiler.hotspot.CompressEncoding;
import org.graalvm.compiler.hotspot.HotSpotLIRGenerator;
import org.graalvm.compiler.hotspot.nodes.type.KlassPointerStamp;
import org.graalvm.compiler.hotspot.nodes.type.NarrowOopStamp;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.ConvertNode;
import org.graalvm.compiler.nodes.calc.UnaryNode;
import org.graalvm.compiler.nodes.spi.LIRLowerable;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
import org.graalvm.compiler.nodes.type.StampTool;

import jdk.vm.ci.hotspot.HotSpotCompressedNullConstant;
import jdk.vm.ci.hotspot.HotSpotConstant;
import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.ConstantReflectionProvider;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.Value;

Compress or uncompress an oop or metaspace pointer.
/** * Compress or uncompress an oop or metaspace pointer. */
@NodeInfo(nameTemplate = "{p#op/s}", cycles = CYCLES_2, size = SIZE_2) public final class CompressionNode extends UnaryNode implements ConvertNode, LIRLowerable { public static final NodeClass<CompressionNode> TYPE = NodeClass.create(CompressionNode.class); public enum CompressionOp { Compress, Uncompress } protected final CompressionOp op; protected final CompressEncoding encoding; public CompressionNode(CompressionOp op, ValueNode input, CompressEncoding encoding) { super(TYPE, mkStamp(op, input.stamp(), encoding), input); this.op = op; this.encoding = encoding; } @Override public Stamp foldStamp(Stamp newStamp) { assert newStamp.isCompatible(getValue().stamp()); return mkStamp(op, newStamp, encoding); } public static CompressionNode compress(ValueNode input, CompressEncoding encoding) { return input.graph().unique(new CompressionNode(CompressionOp.Compress, input, encoding)); } public static CompressionNode compressNoUnique(ValueNode input, CompressEncoding encoding) { return new CompressionNode(CompressionOp.Compress, input, encoding); } public static CompressionNode uncompress(ValueNode input, CompressEncoding encoding) { return input.graph().unique(new CompressionNode(CompressionOp.Uncompress, input, encoding)); } private static Constant compress(Constant c) { if (JavaConstant.NULL_POINTER.equals(c)) { return HotSpotCompressedNullConstant.COMPRESSED_NULL; } else if (c instanceof HotSpotConstant) { return ((HotSpotConstant) c).compress(); } else { throw GraalError.shouldNotReachHere("invalid constant input for compress op: " + c); } } private static Constant uncompress(Constant c) { if (c instanceof HotSpotConstant) { return ((HotSpotConstant) c).uncompress(); } else { throw GraalError.shouldNotReachHere("invalid constant input for uncompress op: " + c); } } @Override public Constant convert(Constant c, ConstantReflectionProvider constantReflection) { switch (op) { case Compress: return compress(c); case Uncompress: return uncompress(c); default: throw GraalError.shouldNotReachHere(); } } @Override public Constant reverse(Constant c, ConstantReflectionProvider constantReflection) { switch (op) { case Compress: return uncompress(c); case Uncompress: return compress(c); default: throw GraalError.shouldNotReachHere(); } } @Override public boolean isLossless() { return true; } private static Stamp mkStamp(CompressionOp op, Stamp input, CompressEncoding encoding) { switch (op) { case Compress: if (input instanceof ObjectStamp) { // compressed oop return NarrowOopStamp.compressed((ObjectStamp) input, encoding); } else if (input instanceof KlassPointerStamp) { // compressed klass pointer return ((KlassPointerStamp) input).compressed(encoding); } break; case Uncompress: if (input instanceof NarrowOopStamp) { // oop assert encoding.equals(((NarrowOopStamp) input).getEncoding()); return ((NarrowOopStamp) input).uncompressed(); } else if (input instanceof KlassPointerStamp) { // metaspace pointer assert encoding.equals(((KlassPointerStamp) input).getEncoding()); return ((KlassPointerStamp) input).uncompressed(); } break; } throw GraalError.shouldNotReachHere(String.format("Unexpected input stamp %s", input)); } public CompressionOp getOp() { return op; } public CompressEncoding getEncoding() { return encoding; } @Override public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) { if (forValue.isConstant()) { if (GeneratePIC.getValue()) { // We always want uncompressed constants return this; } int stableDimension = ((ConstantNode) forValue).getStableDimension(); boolean isDefaultStable = ((ConstantNode) forValue).isDefaultStable(); return ConstantNode.forConstant(stamp(), convert(forValue.asConstant(), tool.getConstantReflection()), stableDimension, isDefaultStable, tool.getMetaAccess()); } else if (forValue instanceof CompressionNode) { CompressionNode other = (CompressionNode) forValue; if (op != other.op && encoding.equals(other.encoding)) { return other.getValue(); } } return this; } @Override public void generate(NodeLIRBuilderTool gen) { HotSpotLIRGenerator hsGen = (HotSpotLIRGenerator) gen.getLIRGeneratorTool(); boolean nonNull; if (getValue().stamp() instanceof AbstractObjectStamp) { nonNull = StampTool.isPointerNonNull(getValue().stamp()); } else { // metaspace pointers are never null nonNull = true; } Value result; switch (op) { case Compress: result = hsGen.emitCompress(gen.operand(getValue()), encoding, nonNull); break; case Uncompress: result = hsGen.emitUncompress(gen.operand(getValue()), encoding, nonNull); break; default: throw GraalError.shouldNotReachHere(); } gen.setResult(this, result); } @NodeIntrinsic public static native Object compression(@ConstantNodeParameter CompressionOp op, Object object, @ConstantNodeParameter CompressEncoding encoding); }