1 /*
2 * Copyright (c) 1999, 2021, 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
26 package com.sun.tools.javac.jvm;
27
28 import com.sun.tools.javac.util.Name;
29
30
31 /** A JVM class file.
32 *
33 * <p>Generic Java classfiles have one additional attribute for classes,
34 * methods and fields:
35 * <pre>
36 * "Signature" (u4 attr-length, u2 signature-index)
37 * </pre>
38 *
39 * <p>A signature gives the full Java type of a method or field. When
40 * used as a class attribute, it indicates type parameters, followed
41 * by supertype, followed by all interfaces.
42 * <pre>
43 * methodOrFieldSignature ::= type
44 * classSignature ::= [ typeparams ] supertype { interfacetype }
45 * </pre>
46 * <p>The type syntax in signatures is extended as follows:
47 * <pre>{@literal
48 * type ::= ... | classtype | methodtype | typevar
49 * classtype ::= classsig { '.' classsig }
50 * classig ::= 'L' name [typeargs] ';'
51 * methodtype ::= [ typeparams ] '(' { type } ')' type
52 * typevar ::= 'T' name ';'
53 * typeargs ::= '<' type { type } '>'
54 * typeparams ::= '<' typeparam { typeparam } '>'
55 * typeparam ::= name ':' type
56 * }</pre>
57 * <p>This class defines constants used in class files as well
58 * as routines to convert between internal ``.'' and external ``/''
59 * separators in class names.
60 *
61 * <p><b>This is NOT part of any supported API.
62 * If you write code that depends on this, you do so at your own risk.
63 * This code and its internal interfaces are subject to change or
64 * deletion without notice.</b> */
65 public class ClassFile {
66
67 public static final int JAVA_MAGIC = 0xCAFEBABE;
68
69 // see Target
70 public static final int CONSTANT_Utf8 = 1;
71 public static final int CONSTANT_Unicode = 2;
72 public static final int CONSTANT_Integer = 3;
73 public static final int CONSTANT_Float = 4;
74 public static final int CONSTANT_Long = 5;
75 public static final int CONSTANT_Double = 6;
76 public static final int CONSTANT_Class = 7;
77 public static final int CONSTANT_String = 8;
78 public static final int CONSTANT_Fieldref = 9;
79 public static final int CONSTANT_Methodref = 10;
80 public static final int CONSTANT_InterfaceMethodref = 11;
81 public static final int CONSTANT_NameandType = 12;
82 public static final int CONSTANT_MethodHandle = 15;
83 public static final int CONSTANT_MethodType = 16;
84 public static final int CONSTANT_Dynamic = 17;
85 public static final int CONSTANT_InvokeDynamic = 18;
86 public static final int CONSTANT_Module = 19;
87 public static final int CONSTANT_Package = 20;
88
89 public static final int REF_getField = 1;
90 public static final int REF_getStatic = 2;
91 public static final int REF_putField = 3;
92 public static final int REF_putStatic = 4;
93 public static final int REF_invokeVirtual = 5;
94 public static final int REF_invokeStatic = 6;
95 public static final int REF_invokeSpecial = 7;
96 public static final int REF_newInvokeSpecial = 8;
97 public static final int REF_invokeInterface = 9;
98
99 public static final int MAX_PARAMETERS = 0xff;
100 public static final int MAX_DIMENSIONS = 0xff;
101 public static final int MAX_CODE = 0xffff;
102 public static final int MAX_LOCALS = 0xffff;
103 public static final int MAX_STACK = 0xffff;
104
105 public static final int PREVIEW_MINOR_VERSION = 0xffff;
106
107 public enum Version {
108 V45_3(45, 3), // base level for all attributes
109 V48(48, 0), // JDK 1.4
110 V49(49, 0), // JDK 1.5: enum, generics, annotations
111 V50(50, 0), // JDK 1.6: stackmaps
112 V51(51, 0), // JDK 1.7
113 V52(52, 0), // JDK 1.8: lambda, type annos, param names
114 V53(53, 0), // JDK 1.9: modules, indy string concat
115 V54(54, 0), // JDK 10
116 V55(55, 0), // JDK 11: constant dynamic, nest mates
117 V56(56, 0), // JDK 12
118 V57(57, 0), // JDK 13
119 V58(58, 0), // JDK 14
120 V59(59, 0), // JDK 15
121 V60(60, 0), // JDK 16
122 V61(61, 0), // JDK 17
123 V62(62, 0), // JDK 18
124 V63(63, 0), // JDK 19
125 V64(64, 0), // JDK 20
126 V65(65, 0); // JDK 21
127 Version(int major, int minor) {
128 this.major = major;
129 this.minor = minor;
130 }
131 public final int major, minor;
132
133 private static final Version MIN = values()[0];
134 /** Return the least version supported, MIN */
135 public static Version MIN() { return MIN; }
136
137 private static final Version MAX = values()[values().length-1];
138 /** Return the largest version supported, MAX */
139 public static Version MAX() { return MAX; }
140 }
141
142
143 /************************************************************************
144 * String Translation Routines
145 ***********************************************************************/
146
147 /**
148 * Return internal representation of buf[offset..offset+len-1], converting '/' to '.'.
149 *
150 * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
151 * which defines "internal name" to be the form using "/" instead of "."
152 */
153 public static byte[] internalize(byte[] buf, int offset, int len) {
154 byte[] translated = new byte[len];
155 for (int j = 0; j < len; j++) {
156 byte b = buf[offset + j];
157 if (b == '/') translated[j] = (byte) '.';
158 else translated[j] = b;
159 }
160 return translated;
161 }
162
163 /**
164 * Return internal representation of given name, converting '/' to '.'.
165 *
166 * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
167 * which defines "internal name" to be the form using "/" instead of "."
168 */
169 public static Name internalize(Name name) {
170 return name.table.names.fromString(name.toString().replace('/', '.'));
171 }
172
173 /**
174 * Return external representation of given name, converting '/' to '.'.
175 *
176 * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
177 * which defines "internal name" to be the form using "/" instead of "."
178 */
179 public static Name externalize(Name name) {
180 return name.table.names.fromString(externalize(name.toString()));
181 }
182
183 /**
184 * Return external representation of given name, converting '/' to '.'.
185 *
186 * Note: the naming is the inverse of that used by JVMS 4.2 The Internal Form Of Names,
187 * which defines "internal name" to be the form using "/" instead of "."
188 */
189 public static String externalize(String name) {
190 return name.replace('.', '/');
191 }
192 }