1 /*
2 * Copyright (c) 2002, 2010, 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.OptionName.*;
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 private static final Context.Key<Target> targetKey =
72 new Context.Key<Target>();
73
74 public static Target instance(Context context) {
75 Target instance = context.get(targetKey);
76 if (instance == null) {
77 Options options = Options.instance(context);
78 String targetString = options.get(TARGET);
79 if (targetString != null) instance = lookup(targetString);
80 if (instance == null) instance = DEFAULT;
81 context.put(targetKey, instance);
82 }
83 return instance;
84 }
85
86 private static Target MIN;
87 public static Target MIN() { return MIN; }
88
89 private static Target MAX;
90 public static Target MAX() { return MAX; }
91
92 private static Map<String,Target> tab = new HashMap<String,Target>();
93 static {
94 for (Target t : values()) {
95 if (MIN == null) MIN = t;
96 MAX = t;
97 tab.put(t.name, t);
98 }
99 tab.put("5", JDK1_5);
100 tab.put("6", JDK1_6);
101 tab.put("7", JDK1_7);
102 }
103
104 public final String name;
105 public final int majorVersion;
106 public final int minorVersion;
107 private Target(String name, int majorVersion, int minorVersion) {
108 this.name = name;
109 this.majorVersion = majorVersion;
110 this.minorVersion = minorVersion;
111 }
112
113 public static final Target DEFAULT = JDK1_7;
114
115 public static Target lookup(String name) {
116 return tab.get(name);
117 }
118
119 /** In -target 1.1 and earlier, the compiler is required to emit
120 * synthetic method definitions in abstract classes for interface
121 * methods that are not overridden. We call them "Miranda" methods.
122 */
123 public boolean requiresIproxy() {
124 return compareTo(JDK1_1) <= 0;
125 }
126
127 /** Beginning in 1.4, we take advantage of the possibility of emitting
128 * code to initialize fields before calling the superclass constructor.
129 * This is allowed by the VM spec, but the verifier refused to allow
130 * it until 1.4. This is necesary to translate some code involving
131 * inner classes. See, for example, 4030374.
132 */
133 public boolean initializeFieldsBeforeSuper() {
134 return compareTo(JDK1_4) >= 0;
135 }
136
137 /** Beginning with -target 1.2 we obey the JLS rules for binary
138 * compatibility, emitting as the qualifying type of a reference
139 * to a method or field the type of the qualifier. In earlier
140 * targets we use as the qualifying type the class in which the
141 * member was found. The following methods named
142 * *binaryCompatibility() indicate places where we vary from this
143 * general rule. */
144 public boolean obeyBinaryCompatibility() {
145 return compareTo(JDK1_2) >= 0;
146 }
147
148 /** Starting in 1.5, the compiler uses an array type as
149 * the qualifier for method calls (such as clone) where required by
150 * the language and VM spec. Earlier versions of the compiler
151 * qualified them by Object.
152 */
153 public boolean arrayBinaryCompatibility() {
154 return compareTo(JDK1_5) >= 0;
155 }
156
157 /** Beginning after 1.2, we follow the binary compatibility rules for
158 * interface fields. The 1.2 VMs had bugs handling interface fields
159 * when compiled using binary compatibility (see 4400598), so this is
160 * an accommodation to them.
161 */
162 public boolean interfaceFieldsBinaryCompatibility() {
163 return compareTo(JDK1_2) > 0;
164 }
165
166 /** Beginning in -target 1.5, we follow the binary compatibility
167 * rules for interface methods that redefine Object methods.
168 * Earlier VMs had bugs handling such methods compiled using binary
169 * compatibility (see 4392595, 4398791, 4392595, 4400415).
170 * The VMs were fixed during or soon after 1.4. See 4392595.
171 */
172 public boolean interfaceObjectOverridesBinaryCompatibility() {
173 return compareTo(JDK1_5) >= 0;
174 }
175
176 /** Beginning in -target 1.4.2, we make synthetic variables
177 * package-private instead of private. This is to prevent the
178 * necessity of access methods, which effectively relax the
179 * protection of the field but bloat the class files and affect
180 * execution.
181 */
182 public boolean usePrivateSyntheticFields() {
183 return compareTo(JDK1_4_2) < 0;
184 }
185
186 /** Sometimes we need to create a field to cache a value like a
187 * class literal of the assertions flag. In -target 1.4.2 and
188 * later we create a new synthetic class for this instead of
189 * using the outermost class. See 4401576.
190 */
191 public boolean useInnerCacheClass() {
192 return compareTo(JDK1_4_2) >= 0;
193 }
194
195 /** Return true if cldc-style stack maps need to be generated. */
196 public boolean generateCLDCStackmap() {
197 return false;
198 }
199
200 /** Beginning in -target 6, we generate stackmap attribute in
201 * compact format. */
202 public boolean generateStackMapTable() {
203 return compareTo(JDK1_6) >= 0;
204 }
205
206 /** Beginning in -target 6, package-info classes are marked synthetic.
207 */
208 public boolean isPackageInfoSynthetic() {
209 return compareTo(JDK1_6) >= 0;
210 }
211
212 /** Do we generate "empty" stackmap slots after double and long?
213 */
214 public boolean generateEmptyAfterBig() {
215 return false;
216 }
217
218 /** Beginning in 1.5, we have an unsynchronized version of
219 * StringBuffer called StringBuilder that can be used by the
220 * compiler for string concatenation.
221 */
222 public boolean useStringBuilder() {
223 return compareTo(JDK1_5) >= 0;
224 }
225
226 /** Beginning in 1.5, we have flag bits we can use instead of
227 * marker attributes.
228 */
229 public boolean useSyntheticFlag() {
230 return compareTo(JDK1_5) >= 0;
231 }
232 public boolean useEnumFlag() {
233 return compareTo(JDK1_5) >= 0;
234 }
235 public boolean useAnnotationFlag() {
236 return compareTo(JDK1_5) >= 0;
237 }
238 public boolean useVarargsFlag() {
239 return compareTo(JDK1_5) >= 0;
240 }
241 public boolean useBridgeFlag() {
242 return compareTo(JDK1_5) >= 0;
243 }
244
245 /** Return the character to be used in constructing synthetic
246 * identifiers, where not specified by the JLS.
247 */
248 public char syntheticNameChar() {
249 return '$';
250 }
251
252 /** Does the VM have direct support for class literals?
253 */
254 public boolean hasClassLiterals() {
255 return compareTo(JDK1_5) >= 0;
256 }
257
258 /** Does the VM support an invokedynamic instruction?
259 */
260 public boolean hasInvokedynamic() {
261 return compareTo(JDK1_7) >= 0;
262 }
263
264 /** Does the VM support polymorphic method handle invocation?
265 * Affects the linkage information output to the classfile.
266 * An alias for {@code hasInvokedynamic}, since all the JSR 292 features appear together.
267 */
268 public boolean hasMethodHandles() {
269 return hasInvokedynamic();
270 }
271
272 /** Although we may not have support for class literals, should we
273 * avoid initializing the class that the literal refers to?
274 * See 4468823
275 */
276 public boolean classLiteralsNoInit() {
277 return compareTo(JDK1_4_2) >= 0;
278 }
279
280 /** Although we may not have support for class literals, when we
281 * throw a NoClassDefFoundError, should we initialize its cause?
282 */
283 public boolean hasInitCause() {
284 return compareTo(JDK1_4) >= 0;
285 }
286
287 /** For bootstrapping, we use J2SE1.4's wrapper class constructors
288 * to implement boxing.
289 */
290 public boolean boxWithConstructors() {
291 return compareTo(JDK1_5) < 0;
292 }
293
294 /** For bootstrapping, we use J2SE1.4's java.util.Collection
295 * instead of java.lang.Iterable.
296 */
297 public boolean hasIterable() {
298 return compareTo(JDK1_5) >= 0;
299 }
300
301 /** For bootstrapping javac only, we do without java.lang.Enum if
302 * necessary.
303 */
304 public boolean compilerBootstrap(Symbol c) {
305 return
306 this == JSR14 &&
307 (c.flags() & Flags.ENUM) != 0 &&
308 c.flatName().toString().startsWith("com.sun.tools.")
309 // && !Target.class.getSuperclass().getName().equals("java.lang.Enum")
310 ;
311 }
312
313 /** In J2SE1.5.0, we introduced the "EnclosingMethod" attribute
314 * for improved reflection support.
315 */
316 public boolean hasEnclosingMethodAttribute() {
317 return compareTo(JDK1_5) >= 0 || this == JSR14;
318 }
319 }