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 */
23package jdk.vm.ci.hotspot;
24
25import java.lang.invoke.CallSite;
26import java.util.Objects;
27
28import jdk.vm.ci.meta.Assumptions;
29import jdk.vm.ci.meta.JavaConstant;
30import jdk.vm.ci.meta.ResolvedJavaType;
31import 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 */
37public interface HotSpotObjectConstant extends JavaConstant, HotSpotConstant, VMConstant {
38
39    JavaConstant compress();
40
41    JavaConstant uncompress();
42
43    /**
44     * Gets the resolved Java type of the object represented by this constant.
45     */
46    HotSpotResolvedObjectType getType();
47
48    /**
49     * Gets the result of {@link Class#getClassLoader()} for the {@link Class} object represented by
50     * this constant.
51     *
52     * @return {@code null} if this constant does not represent a {@link Class} object
53     */
54    JavaConstant getClassLoader();
55
56    /**
57     * Gets the {@linkplain System#identityHashCode(Object) identity} has code for the object
58     * represented by this constant.
59     */
60    int getIdentityHashCode();
61
62    /**
63     * Gets the result of {@link Class#getComponentType()} for the {@link Class} object represented
64     * by this constant.
65     *
66     * @return {@code null} if this constant does not represent a {@link Class} object
67     */
68    JavaConstant getComponentType();
69
70    /**
71     * Gets the result of {@link Class#getSuperclass()} for the {@link Class} object represented by
72     * this constant.
73     *
74     * @return {@code null} if this constant does not represent a {@link Class} object
75     */
76    JavaConstant getSuperclass();
77
78    /**
79     * Gets the result of {@link CallSite#getTarget()} for the {@link CallSite} object represented
80     * by this constant.
81     *
82     * @param assumptions used to register an assumption that the {@link CallSite}'s target does not
83     *            change
84     * @return {@code null} if this constant does not represent a {@link CallSite} object
85     */
86    JavaConstant getCallSiteTarget(Assumptions assumptions);
87
88    /**
89     * Determines if this constant represents an {@linkplain String#intern() interned} string.
90     */
91    boolean isInternedString();
92
93    /**
94     * Gets the object represented by this constant represents if it is of a given type.
95     *
96     * @param type the expected type of the object represented by this constant. If the object is
97     *            required to be of this type, then wrap the call to this method in
98     *            {@link Objects#requireNonNull(Object)}.
99     * @return the object value represented by this constant if it is an
100     *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
101     *         {@code null}
102     */
103    <T> T asObject(Class<T> type);
104
105    /**
106     * Gets the object represented by this constant represents if it is of a given type.
107     *
108     * @param type the expected type of the object represented by this constant. If the object is
109     *            required to be of this type, then wrap the call to this method in
110     *            {@link Objects#requireNonNull(Object)}.
111     * @return the object value represented by this constant if it is an
112     *         {@link ResolvedJavaType#isInstance(JavaConstant) instance of} {@code type} otherwise
113     *         {@code null}
114     */
115    Object asObject(ResolvedJavaType type);
116}
117