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 /** JDK 5, codename 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 /** JDK 9, initially an alias for 8. */
64 JDK1_9("1.9", 52, 0);
65
66 private static final Context.Key<Target> targetKey =
67 new Context.Key<Target>();
68
69 public static Target instance(Context context) {
70 Target instance = context.get(targetKey);
71 if (instance == null) {
72 Options options = Options.instance(context);
73 String targetString = options.get(TARGET);
74 if (targetString != null) instance = lookup(targetString);
75 if (instance == null) instance = DEFAULT;
76 context.put(targetKey, instance);
77 }
78 return instance;
79 }
80
81 private static final Target MIN = values()[0];
82 public static Target MIN() { return MIN; }
83
84 private static final Target MAX = values()[values().length - 1];
85 public static Target MAX() { return MAX; }
86
87 private static final Map<String,Target> tab = new HashMap<>();
88 static {
89 for (Target t : values()) {
90 tab.put(t.name, t);
91 }
92 tab.put("5", JDK1_5);
93 tab.put("6", JDK1_6);
94 tab.put("7", JDK1_7);
95 tab.put("8", JDK1_8);
96 tab.put("9", JDK1_9);
97 }
98
99 public final String name;
100 public final int majorVersion;
101 public final int minorVersion;
102 private Target(String name, int majorVersion, int minorVersion) {
103 this.name = name;
104 this.majorVersion = majorVersion;
105 this.minorVersion = minorVersion;
106 }
107
108 public static final Target DEFAULT = JDK1_9;
109
110 public static Target lookup(String name) {
111 return tab.get(name);
112 }
113
114 /** In -target 1.1 and earlier, the compiler is required to emit
115 * synthetic method definitions in abstract classes for interface
116 * methods that are not overridden. We call them "Miranda" methods.
117 */
118 public boolean requiresIproxy() {
119 return compareTo(JDK1_1) <= 0;
120 }
121
122 /** Beginning in 1.4, we take advantage of the possibility of emitting
123 * code to initialize fields before calling the superclass constructor.
124 * This is allowed by the VM spec, but the verifier refused to allow
125 * it until 1.4. This is necesary to translate some code involving
126 * inner classes. See, for example, 4030374.
127 */
128 public boolean initializeFieldsBeforeSuper() {
129 return compareTo(JDK1_4) >= 0;
130 }
131
132 /** Beginning with -target 1.2 we obey the JLS rules for binary
133 * compatibility, emitting as the qualifying type of a reference
134 * to a method or field the type of the qualifier. In earlier
135 * targets we use as the qualifying type the class in which the
136 * member was found. The following methods named
137 * *binaryCompatibility() indicate places where we vary from this
138 * general rule. */
139 public boolean obeyBinaryCompatibility() {
140 return compareTo(JDK1_2) >= 0;
141 }
142
143 /** Starting in 1.5, the compiler uses an array type as
144 * the qualifier for method calls (such as clone) where required by
145 * the language and VM spec. Earlier versions of the compiler
146 * qualified them by Object.
147 */
148 public boolean arrayBinaryCompatibility() {
149 return compareTo(JDK1_5) >= 0;
150 }
151
152 /** Beginning after 1.2, we follow the binary compatibility rules for
153 * interface fields. The 1.2 VMs had bugs handling interface fields
154 * when compiled using binary compatibility (see 4400598), so this is
155 * an accommodation to them.
156 */
157 public boolean interfaceFieldsBinaryCompatibility() {
158 return compareTo(JDK1_2) > 0;
159 }
160
161 /** Beginning in -target 1.5, we follow the binary compatibility
162 * rules for interface methods that redefine Object methods.
163 * Earlier VMs had bugs handling such methods compiled using binary
164 * compatibility (see 4392595, 4398791, 4392595, 4400415).
165 * The VMs were fixed during or soon after 1.4. See 4392595.
166 */
167 public boolean interfaceObjectOverridesBinaryCompatibility() {
168 return compareTo(JDK1_5) >= 0;
169 }
170
171 /** Beginning in -target 1.5, we make synthetic variables
172 * package-private instead of private. This is to prevent the
173 * necessity of access methods, which effectively relax the
174 * protection of the field but bloat the class files and affect
175 * execution.
176 */
177 public boolean usePrivateSyntheticFields() {
178 return compareTo(JDK1_5) < 0;
179 }
180
181 /** Sometimes we need to create a field to cache a value like a
182 * class literal of the assertions flag. In -target 1.5 and
183 * later we create a new synthetic class for this instead of
184 * using the outermost class. See 4401576.
185 */
186 public boolean useInnerCacheClass() {
187 return compareTo(JDK1_5) >= 0;
188 }
189
190 /** Return true if cldc-style stack maps need to be generated. */
191 public boolean generateCLDCStackmap() {
192 return false;
193 }
194
195 /** Beginning in -target 6, we generate stackmap attribute in
196 * compact format. */
197 public boolean generateStackMapTable() {
198 return compareTo(JDK1_6) >= 0;
199 }
200
201 /** Beginning in -target 6, package-info classes are marked synthetic.
202 */
203 public boolean isPackageInfoSynthetic() {
204 return compareTo(JDK1_6) >= 0;
205 }
206
207 /** Do we generate "empty" stackmap slots after double and long?
208 */
209 public boolean generateEmptyAfterBig() {
210 return false;
211 }
212
213 /** Beginning in 1.5, we have an unsynchronized version of
214 * StringBuffer called StringBuilder that can be used by the
215 * compiler for string concatenation.
216 */
217 public boolean useStringBuilder() {
218 return compareTo(JDK1_5) >= 0;
219 }
220
221 /** Beginning in 1.5, we have flag bits we can use instead of
222 * marker attributes.
223 */
224 public boolean useSyntheticFlag() {
225 return compareTo(JDK1_5) >= 0;
226 }
227 public boolean useEnumFlag() {
228 return compareTo(JDK1_5) >= 0;
229 }
230 public boolean useAnnotationFlag() {
231 return compareTo(JDK1_5) >= 0;
232 }
233 public boolean useVarargsFlag() {
234 return compareTo(JDK1_5) >= 0;
235 }
236 public boolean useBridgeFlag() {
237 return compareTo(JDK1_5) >= 0;
238 }
239
240 /** Return the character to be used in constructing synthetic
241 * identifiers, where not specified by the JLS.
242 */
243 public char syntheticNameChar() {
244 return '$';
245 }
246
247 /** Does the VM have direct support for class literals?
248 */
249 public boolean hasClassLiterals() {
250 return compareTo(JDK1_5) >= 0;
251 }
252
253 /** Does the VM support an invokedynamic instruction?
254 */
255 public boolean hasInvokedynamic() {
256 return compareTo(JDK1_7) >= 0;
257 }
258
259 /** Does the VM support polymorphic method handle invocation?
260 * Affects the linkage information output to the classfile.
261 * An alias for {@code hasInvokedynamic}, since all the JSR 292 features appear together.
262 */
263 public boolean hasMethodHandles() {
264 return hasInvokedynamic();
265 }
266
267 /** Although we may not have support for class literals, should we
268 * avoid initializing the class that the literal refers to?
269 * See 4468823
270 */
271 public boolean classLiteralsNoInit() {
272 return compareTo(JDK1_5) >= 0;
273 }
274
275 /** Although we may not have support for class literals, when we
276 * throw a NoClassDefFoundError, should we initialize its cause?
277 */
278 public boolean hasInitCause() {
279 return compareTo(JDK1_4) >= 0;
280 }
281
282 /** For bootstrapping, we use J2SE1.4's wrapper class constructors
283 * to implement boxing.
284 */
285 public boolean boxWithConstructors() {
286 return compareTo(JDK1_5) < 0;
287 }
288
289 /** For bootstrapping, we use J2SE1.4's java.util.Collection
290 * instead of java.lang.Iterable.
291 */
292 public boolean hasIterable() {
293 return compareTo(JDK1_5) >= 0;
294 }
295
296 /** In J2SE1.5.0, we introduced the "EnclosingMethod" attribute
297 * for improved reflection support.
298 */
299 public boolean hasEnclosingMethodAttribute() {
300 return compareTo(JDK1_5) >= 0;
301 }
302 }