1 /*
2 * Copyright (c) 2002, 2013, 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 java.util.*;
29
30 import com.sun.tools.javac.code.Flags;
31 import com.sun.tools.javac.code.Symbol;
32 import com.sun.tools.javac.util.*;
33
34 import static com.sun.tools.javac.main.Option.TARGET;
35
36 /** The classfile version target.
37 *
38 * <p><b>This is NOT part of any supported API.
39 * If you write code that depends on this, you do so at your own risk.
40 * This code and its internal interfaces are subject to change or
41 * deletion without notice.</b>
42 */
43 public enum Target {
44 JDK1_1("1.1", 45, 3),
45 JDK1_2("1.2", 46, 0),
46 JDK1_3("1.3", 47, 0),
47
48 /** J2SE1.4 = Merlin. */
49 JDK1_4("1.4", 48, 0),
50
51 /** Tiger. */
52 JDK1_5("1.5", 49, 0),
53
54 /** JDK 6. */
55 JDK1_6("1.6", 50, 0),
56
57 /** JDK 7. */
58 JDK1_7("1.7", 51, 0),
59
60 /** JDK 8. */
61 JDK1_8("1.8", 52, 0);
62
63 private static final Context.Key<Target> targetKey =
64 new Context.Key<Target>();
65
66 public static Target instance(Context context) {
67 Target instance = context.get(targetKey);
68 if (instance == null) {
69 Options options = Options.instance(context);
70 String targetString = options.get(TARGET);
71 if (targetString != null) instance = lookup(targetString);
72 if (instance == null) instance = DEFAULT;
73 context.put(targetKey, instance);
74 }
75 return instance;
76 }
77
78 private static final Target MIN = values()[0];
79 public static Target MIN() { return MIN; }
80
81 private static final Target MAX = values()[values().length - 1];
82 public static Target MAX() { return MAX; }
83
84 private static final Map<String,Target> tab = new HashMap<String,Target>();
85 static {
86 for (Target t : values()) {
87 tab.put(t.name, t);
88 }
89 tab.put("5", JDK1_5);
90 tab.put("6", JDK1_6);
91 tab.put("7", JDK1_7);
92 tab.put("8", JDK1_8);
93 }
94
95 public final String name;
96 public final int majorVersion;
97 public final int minorVersion;
98 private Target(String name, int majorVersion, int minorVersion) {
99 this.name = name;
100 this.majorVersion = majorVersion;
101 this.minorVersion = minorVersion;
102 }
103
104 public static final Target DEFAULT = JDK1_8;
105
106 public static Target lookup(String name) {
107 return tab.get(name);
108 }
109
110 /** In -target 1.1 and earlier, the compiler is required to emit
111 * synthetic method definitions in abstract classes for interface
112 * methods that are not overridden. We call them "Miranda" methods.
113 */
114 public boolean requiresIproxy() {
115 return compareTo(JDK1_1) <= 0;
116 }
117
118 /** Beginning in 1.4, we take advantage of the possibility of emitting
119 * code to initialize fields before calling the superclass constructor.
120 * This is allowed by the VM spec, but the verifier refused to allow
121 * it until 1.4. This is necesary to translate some code involving
122 * inner classes. See, for example, 4030374.
123 */
124 public boolean initializeFieldsBeforeSuper() {
125 return compareTo(JDK1_4) >= 0;
126 }
127
128 /** Beginning with -target 1.2 we obey the JLS rules for binary
129 * compatibility, emitting as the qualifying type of a reference
130 * to a method or field the type of the qualifier. In earlier
131 * targets we use as the qualifying type the class in which the
132 * member was found. The following methods named
133 * *binaryCompatibility() indicate places where we vary from this
134 * general rule. */
135 public boolean obeyBinaryCompatibility() {
136 return compareTo(JDK1_2) >= 0;
137 }
138
139 /** Starting in 1.5, the compiler uses an array type as
140 * the qualifier for method calls (such as clone) where required by
141 * the language and VM spec. Earlier versions of the compiler
142 * qualified them by Object.
143 */
144 public boolean arrayBinaryCompatibility() {
145 return compareTo(JDK1_5) >= 0;
146 }
147
148 /** Beginning after 1.2, we follow the binary compatibility rules for
149 * interface fields. The 1.2 VMs had bugs handling interface fields
150 * when compiled using binary compatibility (see 4400598), so this is
151 * an accommodation to them.
152 */
153 public boolean interfaceFieldsBinaryCompatibility() {
154 return compareTo(JDK1_2) > 0;
155 }
156
157 /** Beginning in -target 1.5, we follow the binary compatibility
158 * rules for interface methods that redefine Object methods.
159 * Earlier VMs had bugs handling such methods compiled using binary
160 * compatibility (see 4392595, 4398791, 4392595, 4400415).
161 * The VMs were fixed during or soon after 1.4. See 4392595.
162 */
163 public boolean interfaceObjectOverridesBinaryCompatibility() {
164 return compareTo(JDK1_5) >= 0;
165 }
166
167 /** Beginning in -target 1.5, we make synthetic variables
168 * package-private instead of private. This is to prevent the
169 * necessity of access methods, which effectively relax the
170 * protection of the field but bloat the class files and affect
171 * execution.
172 */
173 public boolean usePrivateSyntheticFields() {
174 return compareTo(JDK1_5) < 0;
175 }
176
177 /** Sometimes we need to create a field to cache a value like a
178 * class literal of the assertions flag. In -target 1.5 and
179 * later we create a new synthetic class for this instead of
180 * using the outermost class. See 4401576.
181 */
182 public boolean useInnerCacheClass() {
183 return compareTo(JDK1_5) >= 0;
184 }
185
186 /** Return true if cldc-style stack maps need to be generated. */
187 public boolean generateCLDCStackmap() {
188 return false;
189 }
190
191 /** Beginning in -target 6, we generate stackmap attribute in
192 * compact format. */
193 public boolean generateStackMapTable() {
194 return compareTo(JDK1_6) >= 0;
195 }
196
197 /** Beginning in -target 6, package-info classes are marked synthetic.
198 */
199 public boolean isPackageInfoSynthetic() {
200 return compareTo(JDK1_6) >= 0;
201 }
202
203 /** Do we generate "empty" stackmap slots after double and long?
204 */
205 public boolean generateEmptyAfterBig() {
206 return false;
207 }
208
209 /** Beginning in 1.5, we have an unsynchronized version of
210 * StringBuffer called StringBuilder that can be used by the
211 * compiler for string concatenation.
212 */
213 public boolean useStringBuilder() {
214 return compareTo(JDK1_5) >= 0;
215 }
216
217 /** Beginning in 1.5, we have flag bits we can use instead of
218 * marker attributes.
219 */
220 public boolean useSyntheticFlag() {
221 return compareTo(JDK1_5) >= 0;
222 }
223 public boolean useEnumFlag() {
224 return compareTo(JDK1_5) >= 0;
225 }
226 public boolean useAnnotationFlag() {
227 return compareTo(JDK1_5) >= 0;
228 }
229 public boolean useVarargsFlag() {
230 return compareTo(JDK1_5) >= 0;
231 }
232 public boolean useBridgeFlag() {
233 return compareTo(JDK1_5) >= 0;
234 }
235
236 /** Return the character to be used in constructing synthetic
237 * identifiers, where not specified by the JLS.
238 */
239 public char syntheticNameChar() {
240 return '$';
241 }
242
243 /** Does the VM have direct support for class literals?
244 */
245 public boolean hasClassLiterals() {
246 return compareTo(JDK1_5) >= 0;
247 }
248
249 /** Does the VM support an invokedynamic instruction?
250 */
251 public boolean hasInvokedynamic() {
252 return compareTo(JDK1_7) >= 0;
253 }
254
255 /** Does the VM support polymorphic method handle invocation?
256 * Affects the linkage information output to the classfile.
257 * An alias for {@code hasInvokedynamic}, since all the JSR 292 features appear together.
258 */
259 public boolean hasMethodHandles() {
260 return hasInvokedynamic();
261 }
262
263 /** Although we may not have support for class literals, should we
264 * avoid initializing the class that the literal refers to?
265 * See 4468823
266 */
267 public boolean classLiteralsNoInit() {
268 return compareTo(JDK1_5) >= 0;
269 }
270
271 /** Although we may not have support for class literals, when we
272 * throw a NoClassDefFoundError, should we initialize its cause?
273 */
274 public boolean hasInitCause() {
275 return compareTo(JDK1_4) >= 0;
276 }
277
278 /** For bootstrapping, we use J2SE1.4's wrapper class constructors
279 * to implement boxing.
280 */
281 public boolean boxWithConstructors() {
282 return compareTo(JDK1_5) < 0;
283 }
284
285 /** For bootstrapping, we use J2SE1.4's java.util.Collection
286 * instead of java.lang.Iterable.
287 */
288 public boolean hasIterable() {
289 return compareTo(JDK1_5) >= 0;
290 }
291
292 /** In J2SE1.5.0, we introduced the "EnclosingMethod" attribute
293 * for improved reflection support.
294 */
295 public boolean hasEnclosingMethodAttribute() {
296 return compareTo(JDK1_5) >= 0;
297 }
298 }