1 /*
2 * Copyright (c) 2002, 2012, 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 /** Support for the JSR14 prototype compiler (targeting 1.4 VMs
52 * augmented with a few support classes). This is a transitional
53 * option that will not be supported in the product. */
54 JSR14("jsr14", 48, 0),
55
56 /** The following are undocumented transitional targets that we
57 * had used to test VM fixes in update releases. We do not
58 * promise to retain support for them. */
59 JDK1_4_1("1.4.1", 48, 0),
60 JDK1_4_2("1.4.2", 48, 0),
61
62 /** Tiger. */
63 JDK1_5("1.5", 49, 0),
64
65 /** JDK 6. */
66 JDK1_6("1.6", 50, 0),
67
68 /** JDK 7. */
69 JDK1_7("1.7", 51, 0),
70
71 /** JDK 8. */
72 JDK1_8("1.8", 52, 0);
73
74 private static final Context.Key<Target> targetKey =
75 new Context.Key<Target>();
76
77 public static Target instance(Context context) {
78 Target instance = context.get(targetKey);
79 if (instance == null) {
80 Options options = Options.instance(context);
81 String targetString = options.get(TARGET);
82 if (targetString != null) instance = lookup(targetString);
83 if (instance == null) instance = DEFAULT;
84 context.put(targetKey, instance);
85 }
86 return instance;
87 }
88
89 private static final Target MIN = values()[0];
90 public static Target MIN() { return MIN; }
91
92 private static final Target MAX = values()[values().length - 1];
93 public static Target MAX() { return MAX; }
94
95 private static final Map<String,Target> tab = new HashMap<String,Target>();
96 static {
97 for (Target t : values()) {
98 tab.put(t.name, t);
99 }
100 tab.put("5", JDK1_5);
101 tab.put("6", JDK1_6);
102 tab.put("7", JDK1_7);
103 tab.put("8", JDK1_8);
104 }
105
106 public final String name;
107 public final int majorVersion;
108 public final int minorVersion;
109 private Target(String name, int majorVersion, int minorVersion) {
110 this.name = name;
111 this.majorVersion = majorVersion;
112 this.minorVersion = minorVersion;
113 }
114
115 public static final Target DEFAULT = JDK1_8;
116
117 public static Target lookup(String name) {
118 return tab.get(name);
119 }
120
121 /** In -target 1.1 and earlier, the compiler is required to emit
122 * synthetic method definitions in abstract classes for interface
123 * methods that are not overridden. We call them "Miranda" methods.
124 */
125 public boolean requiresIproxy() {
126 return compareTo(JDK1_1) <= 0;
127 }
128
129 /** Beginning in 1.4, we take advantage of the possibility of emitting
130 * code to initialize fields before calling the superclass constructor.
131 * This is allowed by the VM spec, but the verifier refused to allow
132 * it until 1.4. This is necesary to translate some code involving
133 * inner classes. See, for example, 4030374.
134 */
135 public boolean initializeFieldsBeforeSuper() {
136 return compareTo(JDK1_4) >= 0;
137 }
138
139 /** Beginning with -target 1.2 we obey the JLS rules for binary
140 * compatibility, emitting as the qualifying type of a reference
141 * to a method or field the type of the qualifier. In earlier
142 * targets we use as the qualifying type the class in which the
143 * member was found. The following methods named
144 * *binaryCompatibility() indicate places where we vary from this
145 * general rule. */
146 public boolean obeyBinaryCompatibility() {
147 return compareTo(JDK1_2) >= 0;
148 }
149
150 /** Starting in 1.5, the compiler uses an array type as
151 * the qualifier for method calls (such as clone) where required by
152 * the language and VM spec. Earlier versions of the compiler
153 * qualified them by Object.
154 */
155 public boolean arrayBinaryCompatibility() {
156 return compareTo(JDK1_5) >= 0;
157 }
158
159 /** Beginning after 1.2, we follow the binary compatibility rules for
160 * interface fields. The 1.2 VMs had bugs handling interface fields
161 * when compiled using binary compatibility (see 4400598), so this is
162 * an accommodation to them.
163 */
164 public boolean interfaceFieldsBinaryCompatibility() {
165 return compareTo(JDK1_2) > 0;
166 }
167
168 /** Beginning in -target 1.5, we follow the binary compatibility
169 * rules for interface methods that redefine Object methods.
170 * Earlier VMs had bugs handling such methods compiled using binary
171 * compatibility (see 4392595, 4398791, 4392595, 4400415).
172 * The VMs were fixed during or soon after 1.4. See 4392595.
173 */
174 public boolean interfaceObjectOverridesBinaryCompatibility() {
175 return compareTo(JDK1_5) >= 0;
176 }
177
178 /** Beginning in -target 1.4.2, we make synthetic variables
179 * package-private instead of private. This is to prevent the
180 * necessity of access methods, which effectively relax the
181 * protection of the field but bloat the class files and affect
182 * execution.
183 */
184 public boolean usePrivateSyntheticFields() {
185 return compareTo(JDK1_4_2) < 0;
186 }
187
188 /** Sometimes we need to create a field to cache a value like a
189 * class literal of the assertions flag. In -target 1.4.2 and
190 * later we create a new synthetic class for this instead of
191 * using the outermost class. See 4401576.
192 */
193 public boolean useInnerCacheClass() {
194 return compareTo(JDK1_4_2) >= 0;
195 }
196
197 /** Return true if cldc-style stack maps need to be generated. */
198 public boolean generateCLDCStackmap() {
199 return false;
200 }
201
202 /** Beginning in -target 6, we generate stackmap attribute in
203 * compact format. */
204 public boolean generateStackMapTable() {
205 return compareTo(JDK1_6) >= 0;
206 }
207
208 /** Beginning in -target 6, package-info classes are marked synthetic.
209 */
210 public boolean isPackageInfoSynthetic() {
211 return compareTo(JDK1_6) >= 0;
212 }
213
214 /** Do we generate "empty" stackmap slots after double and long?
215 */
216 public boolean generateEmptyAfterBig() {
217 return false;
218 }
219
220 /** Beginning in 1.5, we have an unsynchronized version of
221 * StringBuffer called StringBuilder that can be used by the
222 * compiler for string concatenation.
223 */
224 public boolean useStringBuilder() {
225 return compareTo(JDK1_5) >= 0;
226 }
227
228 /** Beginning in 1.5, we have flag bits we can use instead of
229 * marker attributes.
230 */
231 public boolean useSyntheticFlag() {
232 return compareTo(JDK1_5) >= 0;
233 }
234 public boolean useEnumFlag() {
235 return compareTo(JDK1_5) >= 0;
236 }
237 public boolean useAnnotationFlag() {
238 return compareTo(JDK1_5) >= 0;
239 }
240 public boolean useVarargsFlag() {
241 return compareTo(JDK1_5) >= 0;
242 }
243 public boolean useBridgeFlag() {
244 return compareTo(JDK1_5) >= 0;
245 }
246
247 /** Return the character to be used in constructing synthetic
248 * identifiers, where not specified by the JLS.
249 */
250 public char syntheticNameChar() {
251 return '$';
252 }
253
254 /** Does the VM have direct support for class literals?
255 */
256 public boolean hasClassLiterals() {
257 return compareTo(JDK1_5) >= 0;
258 }
259
260 /** Does the VM support an invokedynamic instruction?
261 */
262 public boolean hasInvokedynamic() {
263 return compareTo(JDK1_7) >= 0;
264 }
265
266 /** Does the VM support polymorphic method handle invocation?
267 * Affects the linkage information output to the classfile.
268 * An alias for {@code hasInvokedynamic}, since all the JSR 292 features appear together.
269 */
270 public boolean hasMethodHandles() {
271 return hasInvokedynamic();
272 }
273
274 /** Although we may not have support for class literals, should we
275 * avoid initializing the class that the literal refers to?
276 * See 4468823
277 */
278 public boolean classLiteralsNoInit() {
279 return compareTo(JDK1_4_2) >= 0;
280 }
281
282 /** Although we may not have support for class literals, when we
283 * throw a NoClassDefFoundError, should we initialize its cause?
284 */
285 public boolean hasInitCause() {
286 return compareTo(JDK1_4) >= 0;
287 }
288
289 /** For bootstrapping, we use J2SE1.4's wrapper class constructors
290 * to implement boxing.
291 */
292 public boolean boxWithConstructors() {
293 return compareTo(JDK1_5) < 0;
294 }
295
296 /** For bootstrapping, we use J2SE1.4's java.util.Collection
297 * instead of java.lang.Iterable.
298 */
299 public boolean hasIterable() {
300 return compareTo(JDK1_5) >= 0;
301 }
302
303 /** For bootstrapping javac only, we do without java.lang.Enum if
304 * necessary.
305 */
306 public boolean compilerBootstrap(Symbol c) {
307 return
308 this == JSR14 &&
309 (c.flags() & Flags.ENUM) != 0 &&
310 c.flatName().toString().startsWith("com.sun.tools.")
311 // && !Target.class.getSuperclass().getName().equals("java.lang.Enum")
312 ;
313 }
314
315 /** In J2SE1.5.0, we introduced the "EnclosingMethod" attribute
316 * for improved reflection support.
317 */
318 public boolean hasEnclosingMethodAttribute() {
319 return compareTo(JDK1_5) >= 0 || this == JSR14;
320 }
321 }