1 /*
   2  * Copyright (c) 2009, 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 java.lang.invoke.CallSite;
  26 import java.util.Objects;
  27 
  28 import jdk.vm.ci.meta.Assumptions;
  29 import jdk.vm.ci.meta.JavaConstant;
  30 import jdk.vm.ci.meta.ResolvedJavaType;
  31 import jdk.vm.ci.meta.VMConstant;
  32 
  33 /**
  34  * Represents a constant non-{@code null} object reference, within the compiler and across the
  35  * compiler/runtime interface.
  36  */
  37 public interface HotSpotObjectConstant extends JavaConstant, HotSpotConstant, VMConstant {
  38 
  39     @Override
  40     JavaConstant compress();
  41 
  42     @Override
  43     JavaConstant uncompress();
  44 
  45     /**
  46      * Gets the resolved Java type of the object represented by this constant.
  47      */
  48     HotSpotResolvedObjectType getType();
  49 
  50     /**
  51      * Gets the {@linkplain System#identityHashCode(Object) identity} has code for the object
  52      * represented by this constant.
  53      */
  54     int getIdentityHashCode();
  55 
  56     /**
  57      * Gets the result of {@link CallSite#getTarget()} for the {@link CallSite} object represented
  58      * by this constant.
  59      *
  60      * @param assumptions used to register an assumption that the {@link CallSite}'s target does not
  61      *            change
  62      * @return {@code null} if this constant does not represent a {@link CallSite} object
  63      */
  64     JavaConstant getCallSiteTarget(Assumptions assumptions);
  65 
  66     /**
  67      * Determines if this constant represents an {@linkplain String#intern() interned} string.
  68      */
  69     boolean isInternedString();
  70 
  71     /**
  72      * Gets the object represented by this constant represents if it is of a given type.
  73      *
  74      * @param type the expected type of the object represented by this constant. If the object is
  75      *            required to be of this type, then wrap the call to this method in
  76      *            {@link Objects#requireNonNull(Object)}.
  77      * @return the object value represented by this constant if it is an
  78      *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
  79      *         {@code null}
  80      */
  81     <T> T asObject(Class<T> type);
  82 
  83     /**
  84      * Gets the object represented by this constant represents if it is of a given type.
  85      *
  86      * @param type the expected type of the object represented by this constant. If the object is
  87      *            required to be of this type, then wrap the call to this method in
  88      *            {@link Objects#requireNonNull(Object)}.
  89      * @return the object value represented by this constant if it is an
  90      *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
  91      *         {@code null}
  92      */
  93     Object asObject(ResolvedJavaType type);
  94 }