ClassFile.java revision 3822:d8766c39123a 
1/*
2 * Copyright (c) 1999, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.tools.javac.jvm;
27
28import com.sun.tools.javac.code.Type;
29import com.sun.tools.javac.code.Types;
30import com.sun.tools.javac.code.Types.UniqueType;
31import com.sun.tools.javac.util.Name;
32
33
34/** A JVM class file.
35 *
36 *  <p>Generic Java classfiles have one additional attribute for classes,
37 *  methods and fields:
38 *  <pre>
39 *   "Signature" (u4 attr-length, u2 signature-index)
40 *  </pre>
41 *
42 *  <p>A signature gives the full Java type of a method or field. When
43 *  used as a class attribute, it indicates type parameters, followed
44 *  by supertype, followed by all interfaces.
45 *  <pre>
46 *     methodOrFieldSignature ::= type
47 *     classSignature         ::= [ typeparams ] supertype { interfacetype }
48 *  </pre>
49 *  <p>The type syntax in signatures is extended as follows:
50 *  <pre>{@literal
51 *     type       ::= ... | classtype | methodtype | typevar
52 *     classtype  ::= classsig { '.' classsig }
53 *     classig    ::= 'L' name [typeargs] ';'
54 *     methodtype ::= [ typeparams ] '(' { type } ')' type
55 *     typevar    ::= 'T' name ';'
56 *     typeargs   ::= '<' type { type } '>'
57 *     typeparams ::= '<' typeparam { typeparam } '>'
58 *     typeparam  ::= name ':' type
59 *  }</pre>
60 *  <p>This class defines constants used in class files as well
61 *  as routines to convert between internal ``.'' and external ``/''
62 *  separators in class names.
63 *
64 *  <p><b>This is NOT part of any supported API.
65 *  If you write code that depends on this, you do so at your own risk.
66 *  This code and its internal interfaces are subject to change or
67 *  deletion without notice.</b> */
68public class ClassFile {
69
70    public final static int JAVA_MAGIC = 0xCAFEBABE;
71
72    // see Target
73    public final static int CONSTANT_Utf8 = 1;
74    public final static int CONSTANT_Unicode = 2;
75    public final static int CONSTANT_Integer = 3;
76    public final static int CONSTANT_Float = 4;
77    public final static int CONSTANT_Long = 5;
78    public final static int CONSTANT_Double = 6;
79    public final static int CONSTANT_Class = 7;
80    public final static int CONSTANT_String = 8;
81    public final static int CONSTANT_Fieldref = 9;
82    public final static int CONSTANT_Methodref = 10;
83    public final static int CONSTANT_InterfaceMethodref = 11;
84    public final static int CONSTANT_NameandType = 12;
85    public final static int CONSTANT_MethodHandle = 15;
86    public final static int CONSTANT_MethodType = 16;
87    public final static int CONSTANT_InvokeDynamic = 18;
88    public final static int CONSTANT_Module = 19;
89    public final static int CONSTANT_Package = 20;
90
91    public final static int REF_getField = 1;
92    public final static int REF_getStatic = 2;
93    public final static int REF_putField = 3;
94    public final static int REF_putStatic = 4;
95    public final static int REF_invokeVirtual = 5;
96    public final static int REF_invokeStatic = 6;
97    public final static int REF_invokeSpecial = 7;
98    public final static int REF_newInvokeSpecial = 8;
99    public final static int REF_invokeInterface = 9;
100
101    public final static int MAX_PARAMETERS = 0xff;
102    public final static int MAX_DIMENSIONS = 0xff;
103    public final static int MAX_CODE = 0xffff;
104    public final static int MAX_LOCALS = 0xffff;
105    public final static int MAX_STACK = 0xffff;
106
107    public enum Version {
108        V45_3(45, 3), // base level for all attributes
109        V49(49, 0),   // JDK 1.5: enum, generics, annotations
110        V50(50, 0),   // JDK 1.6: stackmaps
111        V51(51, 0),   // JDK 1.7
112        V52(52, 0),   // JDK 1.8: lambda, type annos, param names
113        V53(53, 0);   // JDK 1.9: modules, indy string concat
114        Version(int major, int minor) {
115            this.major = major;
116            this.minor = minor;
117        }
118        public final int major, minor;
119
120        private static final Version MIN = values()[0];
121        /** Return the least version supported, MIN */
122        public static Version MIN() { return MIN; }
123
124        private static final Version MAX = values()[values().length-1];
125        /** Return the largest version supported, MAX */
126        public static Version MAX() { return MAX; }
127    }
128
129
130/************************************************************************
131 * String Translation Routines
132 ***********************************************************************/
133
134    /**
135     * Return internal representation of buf[offset..offset+len-1], converting '/' to '.'.
136     *
137     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
138     * which defines "internal name" to be the form using "/" instead of "."
139     */
140    public static byte[] internalize(byte[] buf, int offset, int len) {
141        byte[] translated = new byte[len];
142        for (int j = 0; j < len; j++) {
143            byte b = buf[offset + j];
144            if (b == '/') translated[j] = (byte) '.';
145            else translated[j] = b;
146        }
147        return translated;
148    }
149
150    /**
151     * Return internal representation of given name, converting '/' to '.'.
152     *
153     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
154     * which defines "internal name" to be the form using "/" instead of "."
155     */
156    public static byte[] internalize(Name name) {
157        return internalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
158    }
159
160    /**
161     * Return external representation of buf[offset..offset+len-1], converting '.' to '/'.
162     *
163     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
164     * which defines "internal name" to be the form using "/" instead of "."
165     */
166    public static byte[] externalize(byte[] buf, int offset, int len) {
167        byte[] translated = new byte[len];
168        for (int j = 0; j < len; j++) {
169            byte b = buf[offset + j];
170            if (b == '.') translated[j] = (byte) '/';
171            else translated[j] = b;
172        }
173        return translated;
174    }
175
176    /**
177     * Return external representation of given name, converting '/' to '.'.
178     *
179     * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
180     * which defines "internal name" to be the form using "/" instead of "."
181     */
182    public static byte[] externalize(Name name) {
183        return externalize(name.getByteArray(), name.getByteOffset(), name.getByteLength());
184    }
185
186/************************************************************************
187 * Name-and-type
188 ***********************************************************************/
189
190    /** A class for the name-and-type signature of a method or field.
191     */
192    public static class NameAndType {
193        Name name;
194        UniqueType uniqueType;
195        Types types;
196
197        NameAndType(Name name, Type type, Types types) {
198            this.name = name;
199            this.uniqueType = new UniqueType(type, types);
200            this.types = types;
201        }
202
203        void setType(Type type) {
204            this.uniqueType = new UniqueType(type, types);
205        }
206
207        @Override
208        public boolean equals(Object other) {
209            return (other instanceof NameAndType &&
210                    name == ((NameAndType) other).name &&
211                        uniqueType.equals(((NameAndType) other).uniqueType));
212        }
213
214        @Override
215        public int hashCode() {
216            return name.hashCode() * uniqueType.hashCode();
217        }
218    }
219}
220