1 /*
   2  * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.hotspot.replacements;
  24 
  25 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.referentOffset;
  26 import static org.graalvm.compiler.replacements.SnippetTemplate.DEFAULT_REPLACER;
  27 
  28 import org.graalvm.compiler.api.replacements.Snippet;
  29 import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
  30 import org.graalvm.compiler.nodes.extended.FixedValueAnchorNode;
  31 import org.graalvm.compiler.nodes.extended.UnsafeLoadNode;
  32 import org.graalvm.compiler.nodes.memory.HeapAccess.BarrierType;
  33 import org.graalvm.compiler.nodes.spi.LoweringTool;
  34 import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
  35 import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
  36 import org.graalvm.compiler.replacements.SnippetTemplate.SnippetInfo;
  37 import org.graalvm.compiler.replacements.Snippets;
  38 import org.graalvm.compiler.word.Word;
  39 
  40 import jdk.vm.ci.code.TargetDescription;
  41 
  42 public class UnsafeLoadSnippets implements Snippets {
  43 
  44     @Snippet
  45     public static Object lowerUnsafeLoad(Object object, long offset) {
  46         Object fixedObject = FixedValueAnchorNode.getObject(object);
  47         if (object instanceof java.lang.ref.Reference && referentOffset() == offset) {
  48             return Word.objectToTrackedPointer(fixedObject).readObject((int) offset, BarrierType.PRECISE);
  49         } else {
  50             return Word.objectToTrackedPointer(fixedObject).readObject((int) offset, BarrierType.NONE);
  51         }
  52     }
  53 
  54     public static class Templates extends AbstractTemplates {
  55 
  56         private final SnippetInfo unsafeLoad = snippet(UnsafeLoadSnippets.class, "lowerUnsafeLoad");
  57 
  58         public Templates(HotSpotProviders providers, TargetDescription target) {
  59             super(providers, providers.getSnippetReflection(), target);
  60         }
  61 
  62         public void lower(UnsafeLoadNode load, LoweringTool tool) {
  63             Arguments args = new Arguments(unsafeLoad, load.graph().getGuardsStage(), tool.getLoweringStage());
  64             args.add("object", load.object());
  65             args.add("offset", load.offset());
  66             template(args).instantiate(providers.getMetaAccess(), load, DEFAULT_REPLACER, args);
  67         }
  68     }
  69 }