EncodedSymbolConstant.java revision 12968:4d8a004e5c6d 
1/*
2 * Copyright (c) 2016, 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 org.graalvm.compiler.hotspot.replacements;
24
25import java.io.ByteArrayOutputStream;
26import java.io.DataOutputStream;
27import java.nio.ByteBuffer;
28
29import org.graalvm.compiler.core.common.PermanentBailoutException;
30import org.graalvm.compiler.core.common.type.DataPointerConstant;
31
32import jdk.vm.ci.hotspot.HotSpotMetaspaceConstant;
33import jdk.vm.ci.hotspot.HotSpotObjectConstant;
34import jdk.vm.ci.hotspot.HotSpotResolvedJavaMethod;
35import jdk.vm.ci.hotspot.HotSpotResolvedObjectType;
36import jdk.vm.ci.meta.Constant;
37
38/**
39 * Represents an encoded representation of a constant.
40 */
41public final class EncodedSymbolConstant extends DataPointerConstant {
42    private final Constant constant;
43    private byte[] bytes;
44
45    public EncodedSymbolConstant(Constant constant) {
46        super(1);
47        this.constant = constant;
48    }
49
50    @Override
51    public int getSerializedSize() {
52        return getEncodedConstant().length;
53    }
54
55    @Override
56    public void serialize(ByteBuffer buffer) {
57        buffer.put(getEncodedConstant());
58    }
59
60    /**
61     * Converts a string to a byte array with modified UTF-8 encoding. The first two bytes of the
62     * byte array store the length of the string in bytes.
63     *
64     * @param s a java.lang.String in UTF-16
65     */
66    private static byte[] toUTF8String(String s) {
67        try (ByteArrayOutputStream bytes = new ByteArrayOutputStream()) {
68            DataOutputStream stream = new DataOutputStream(bytes);
69            stream.writeUTF(s);
70            return bytes.toByteArray();
71        } catch (Exception e) {
72            throw new PermanentBailoutException(e, "String conversion failed: %s", s);
73        }
74    }
75
76    private static byte[] encodeConstant(Constant constant) {
77        assert constant != null;
78        if (constant instanceof HotSpotObjectConstant) {
79            return toUTF8String(((HotSpotObjectConstant) constant).asObject(String.class));
80        } else if (constant instanceof HotSpotMetaspaceConstant) {
81            HotSpotMetaspaceConstant metaspaceConstant = ((HotSpotMetaspaceConstant) constant);
82            HotSpotResolvedObjectType klass = metaspaceConstant.asResolvedJavaType();
83            if (klass != null) {
84                return toUTF8String(klass.getName());
85            }
86            HotSpotResolvedJavaMethod method = metaspaceConstant.asResolvedJavaMethod();
87            if (method != null) {
88                byte[] methodName = toUTF8String(method.getName());
89                byte[] signature = toUTF8String(method.getSignature().toMethodDescriptor());
90                byte[] result = new byte[methodName.length + signature.length];
91                int resultPos = 0;
92                System.arraycopy(methodName, 0, result, resultPos, methodName.length);
93                resultPos += methodName.length;
94                System.arraycopy(signature, 0, result, resultPos, signature.length);
95                resultPos += signature.length;
96                assert resultPos == result.length;
97                return result;
98            }
99
100        }
101        throw new PermanentBailoutException("Encoding of constant %s failed", constant);
102    }
103
104    public byte[] getEncodedConstant() {
105        if (bytes == null) {
106            bytes = encodeConstant(constant);
107        }
108        return bytes;
109    }
110
111    @Override
112    public String toValueString() {
113        return "encoded symbol\"" + constant.toValueString() + "\"";
114    }
115
116}
117