1 /*
   2  * Copyright (c) 2011, 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 jdk.vm.ci.hotspot;
  24 
  25 import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
  26 import jdk.vm.ci.code.InstalledCode;
  27 import jdk.vm.ci.code.InvalidInstalledCodeException;
  28 import jdk.vm.ci.meta.JavaKind;
  29 import jdk.vm.ci.meta.JavaType;
  30 import jdk.vm.ci.meta.ResolvedJavaMethod;
  31 
  32 /**
  33  * Implementation of {@link InstalledCode} for code installed as an nmethod. The nmethod stores a
  34  * weak reference to an instance of this class. This is necessary to keep the nmethod from being
  35  * unloaded while the associated {@link HotSpotNmethod} instance is alive.
  36  * <p>
  37  * Note that there is no (current) way for the reference from an nmethod to a {@link HotSpotNmethod}
  38  * instance to be anything but weak. This is due to the fact that HotSpot does not treat nmethods as
  39  * strong GC roots.
  40  */
  41 public class HotSpotNmethod extends HotSpotInstalledCode {
  42 
  43     /**
  44      * This (indirect) Method* reference is safe since class redefinition preserves all methods
  45      * associated with nmethods in the code cache.
  46      */
  47     private final HotSpotResolvedJavaMethod method;
  48 
  49     private final boolean isDefault;
  50 
  51     public HotSpotNmethod(HotSpotResolvedJavaMethod method, String name, boolean isDefault) {
  52         super(name);
  53         this.method = method;
  54         this.isDefault = isDefault;
  55     }
  56 
  57     public boolean isDefault() {
  58         return isDefault;
  59     }
  60 
  61     public ResolvedJavaMethod getMethod() {
  62         return method;
  63     }
  64 
  65     @Override
  66     public void invalidate() {
  67         compilerToVM().invalidateInstalledCode(this);
  68     }
  69 
  70     @Override
  71     public String toString() {
  72         return String.format("InstalledNmethod[method=%s, codeBlob=0x%x, isDefault=%b, name=%s]", method, getAddress(), isDefault, name);
  73     }
  74 
  75     protected boolean checkThreeObjectArgs() {
  76         assert method.getSignature().getParameterCount(!method.isStatic()) == 3;
  77         assert method.getSignature().getParameterKind(0) == JavaKind.Object;
  78         assert method.getSignature().getParameterKind(1) == JavaKind.Object;
  79         assert !method.isStatic() || method.getSignature().getParameterKind(2) == JavaKind.Object;
  80         return true;
  81     }
  82 
  83     private boolean checkArgs(Object... args) {
  84         JavaType[] sig = method.toParameterTypes();
  85         assert args.length == sig.length : method.format("%H.%n(%p): expected ") + sig.length + " args, got " + args.length;
  86         for (int i = 0; i < sig.length; i++) {
  87             Object arg = args[i];
  88             if (arg == null) {
  89                 assert sig[i].getJavaKind() == JavaKind.Object : method.format("%H.%n(%p): expected arg ") + i + " to be Object, not " + sig[i];
  90             } else if (sig[i].getJavaKind() != JavaKind.Object) {
  91                 assert sig[i].getJavaKind().toBoxedJavaClass() == arg.getClass() : method.format("%H.%n(%p): expected arg ") + i + " to be " + sig[i] + ", not " + arg.getClass();
  92             }
  93         }
  94         return true;
  95     }
  96 
  97     @Override
  98     public Object executeVarargs(Object... args) throws InvalidInstalledCodeException {
  99         assert checkArgs(args);
 100         return compilerToVM().executeInstalledCode(args, this);
 101     }
 102 
 103     @Override
 104     public long getStart() {
 105         return isValid() ? super.getStart() : 0;
 106     }
 107 }