1 /*

        2  * Copyright 2002-2006 Sun Microsystems, Inc.  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.  Sun designates this

        8  * particular file as subject to the "Classpath" exception as provided

        9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

       22  * CA 95054 USA or visit www.sun.com if you need additional information or

       23  * have any 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 /** The classfile version target.

       35  *

       36  *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If

       37  *  you write code that depends on this, you do so at your own risk.

       38  *  This code and its internal interfaces are subject to change or

       39  *  deletion without notice.</b>

       40  */

       41 public enum Target {

       42     JDK1_1("1.1", 45, 3),

       43     JDK1_2("1.2", 46, 0),

       44     JDK1_3("1.3", 47, 0),

       45 

       46     /** J2SE1.4 = Merlin. */

       47     JDK1_4("1.4", 48, 0),

       48 

       49     /** Support for the JSR14 prototype compiler (targeting 1.4 VMs

       50      *  augmented with a few support classes).  This is a transitional

       51      *  option that will not be supported in the product.  */

       52     JSR14("jsr14", 48, 0),

       53 

       54     /** The following are undocumented transitional targets that we

       55      *  had used to test VM fixes in update releases.  We do not

       56      *  promise to retain support for them.  */

       57     JDK1_4_1("1.4.1", 48, 0),

       58     JDK1_4_2("1.4.2", 48, 0),

       59 

       60     /** Tiger. */

       61     JDK1_5("1.5", 49, 0),

       62 

       63     /** JDK 6. */

       64     JDK1_6("1.6", 50, 0),

       65 

       66     /** JDK 7. */

       67     JDK1_7("1.7", 51, 0);

       68 

       69     private static final Context.Key<Target> targetKey =

       70         new Context.Key<Target>();

       71 

       72     public static Target instance(Context context) {

       73         Target instance = context.get(targetKey);

       74         if (instance == null) {

       75             Options options = Options.instance(context);

       76             String targetString = options.get("-target");

       77             if (targetString != null) instance = lookup(targetString);

       78             if (instance == null) instance = DEFAULT;

       79             context.put(targetKey, instance);

       80         }

       81         return instance;

       82     }

       83 

       84     private static Target MIN;

       85     public static Target MIN() { return MIN; }

       86 

       87     private static Target MAX;

       88     public static Target MAX() { return MAX; }

       89 

       90     private static Map<String,Target> tab = new HashMap<String,Target>();

       91     static {

       92         for (Target t : values()) {

       93             if (MIN == null) MIN = t;

       94             MAX = t;

       95             tab.put(t.name, t);

       96         }

       97         tab.put("5", JDK1_5);

       98         tab.put("6", JDK1_6);

       99         tab.put("7", JDK1_7);

      100     }

      101 

      102     public final String name;

      103     public final int majorVersion;

      104     public final int minorVersion;

      105     private Target(String name, int majorVersion, int minorVersion) {

      106         this.name = name;

      107         this.majorVersion = majorVersion;

      108         this.minorVersion = minorVersion;

      109     }

      110 

      111     public static final Target DEFAULT = JDK1_7;

      112 

      113     public static Target lookup(String name) {

      114         return tab.get(name);

      115     }

      116 

      117     /** In -target 1.1 and earlier, the compiler is required to emit

      118      *  synthetic method definitions in abstract classes for interface

      119      *  methods that are not overridden.  We call them "Miranda" methods.

      120      */

      121     public boolean requiresIproxy() {

      122         return compareTo(JDK1_1) <= 0;

      123     }

      124 

      125     /** Beginning in 1.4, we take advantage of the possibility of emitting

      126      *  code to initialize fields before calling the superclass constructor.

      127      *  This is allowed by the VM spec, but the verifier refused to allow

      128      *  it until 1.4.  This is necesary to translate some code involving

      129      *  inner classes.  See, for example, 4030374.

      130      */

      131     public boolean initializeFieldsBeforeSuper() {

      132         return compareTo(JDK1_4) >= 0;

      133     }

      134 

      135     /** Beginning with -target 1.2 we obey the JLS rules for binary

      136      *  compatibility, emitting as the qualifying type of a reference

      137      *  to a method or field the type of the qualifier.  In earlier

      138      *  targets we use as the qualifying type the class in which the

      139      *  member was found.  The following methods named

      140      *  *binaryCompatibility() indicate places where we vary from this

      141      *  general rule. */

      142     public boolean obeyBinaryCompatibility() {

      143         return compareTo(JDK1_2) >= 0;

      144     }

      145 

      146     /** Starting in 1.5, the compiler uses an array type as

      147      *  the qualifier for method calls (such as clone) where required by

      148      *  the language and VM spec.  Earlier versions of the compiler

      149      *  qualified them by Object.

      150      */

      151     public boolean arrayBinaryCompatibility() {

      152         return compareTo(JDK1_5) >= 0;

      153     }

      154 

      155     /** Beginning after 1.2, we follow the binary compatibility rules for

      156      *  interface fields.  The 1.2 VMs had bugs handling interface fields

      157      *  when compiled using binary compatibility (see 4400598), so this is

      158      *  an accommodation to them.

      159      */

      160     public boolean interfaceFieldsBinaryCompatibility() {

      161         return compareTo(JDK1_2) > 0;

      162     }

      163 

      164     /** Beginning in -target 1.5, we follow the binary compatibility

      165      *  rules for interface methods that redefine Object methods.

      166      *  Earlier VMs had bugs handling such methods compiled using binary

      167      *  compatibility (see 4392595, 4398791, 4392595, 4400415).

      168      *  The VMs were fixed during or soon after 1.4.  See 4392595.

      169      */

      170     public boolean interfaceObjectOverridesBinaryCompatibility() {

      171         return compareTo(JDK1_5) >= 0;

      172     }

      173 

      174     /** Beginning in -target 1.4.2, we make synthetic variables

      175      *  package-private instead of private.  This is to prevent the

      176      *  necessity of access methods, which effectively relax the

      177      *  protection of the field but bloat the class files and affect

      178      *  execution.

      179      */

      180     public boolean usePrivateSyntheticFields() {

      181         return compareTo(JDK1_4_2) < 0;

      182     }

      183 

      184     /** Sometimes we need to create a field to cache a value like a

      185      *  class literal of the assertions flag.  In -target 1.4.2 and

      186      *  later we create a new synthetic class for this instead of

      187      *  using the outermost class.  See 4401576.

      188      */

      189     public boolean useInnerCacheClass() {

      190         return compareTo(JDK1_4_2) >= 0;

      191     }

      192 

      193     /** Return true if cldc-style stack maps need to be generated. */

      194     public boolean generateCLDCStackmap() {

      195         return false;

      196     }

      197 

      198     /** Beginning in -target 6, we generate stackmap attribute in

      199      *  compact format. */

      200     public boolean generateStackMapTable() {

      201         return compareTo(JDK1_6) >= 0;

      202     }

      203 

      204     /** Beginning in -target 6, package-info classes are marked synthetic.

      205      */

      206     public boolean isPackageInfoSynthetic() {

      207         return compareTo(JDK1_6) >= 0;

      208     }

      209 

      210     /** Do we generate "empty" stackmap slots after double and long?

      211      */

      212     public boolean generateEmptyAfterBig() {

      213         return false;

      214     }

      215 

      216     /** Beginning in 1.5, we have an unsynchronized version of

      217      *  StringBuffer called StringBuilder that can be used by the

      218      *  compiler for string concatenation.

      219      */

      220     public boolean useStringBuilder() {

      221         return compareTo(JDK1_5) >= 0;

      222     }

      223 

      224     /** Beginning in 1.5, we have flag bits we can use instead of

      225      *  marker attributes.

      226      */

      227     public boolean useSyntheticFlag() {

      228         return compareTo(JDK1_5) >= 0;

      229     }

      230     public boolean useEnumFlag() {

      231         return compareTo(JDK1_5) >= 0;

      232     }

      233     public boolean useAnnotationFlag() {

      234         return compareTo(JDK1_5) >= 0;

      235     }

      236     public boolean useVarargsFlag() {

      237         return compareTo(JDK1_5) >= 0;

      238     }

      239     public boolean useBridgeFlag() {

      240         return compareTo(JDK1_5) >= 0;

      241     }

      242 

      243     /** Return the character to be used in constructing synthetic

      244      *  identifiers, where not specified by the JLS.

      245      */

      246     public char syntheticNameChar() {

      247         return '$';

      248     }

      249 

      250     /** Does the VM have direct support for class literals?

      251      */

      252     public boolean hasClassLiterals() {

      253         return compareTo(JDK1_5) >= 0;

      254     }

      255 

      256     /** Does the VM support an invokedynamic instruction?

      257      */

      258     public boolean hasInvokedynamic() {

      259         return compareTo(JDK1_7) >= 0;

      260     }

      261 

      262     /** Although we may not have support for class literals, should we

      263      *  avoid initializing the class that the literal refers to?

      264      *  See 4468823

      265      */

      266     public boolean classLiteralsNoInit() {

      267         return compareTo(JDK1_4_2) >= 0;

      268     }

      269 

      270     /** Although we may not have support for class literals, when we

      271      *  throw a NoClassDefFoundError, should we initialize its cause?

      272      */

      273     public boolean hasInitCause() {

      274         return compareTo(JDK1_4) >= 0;

      275     }

      276 

      277     /** For bootstrapping, we use J2SE1.4's wrapper class constructors

      278      *  to implement boxing.

      279      */

      280     public boolean boxWithConstructors() {

      281         return compareTo(JDK1_5) < 0;

      282     }

      283 

      284     /** For bootstrapping, we use J2SE1.4's java.util.Collection

      285      *  instead of java.lang.Iterable.

      286      */

      287     public boolean hasIterable() {

      288         return compareTo(JDK1_5) >= 0;

      289     }

      290 

      291     /** For bootstrapping javac only, we do without java.lang.Enum if

      292      *  necessary.

      293      */

      294     public boolean compilerBootstrap(Symbol c) {

      295         return

      296             this == JSR14 &&

      297             (c.flags() & Flags.ENUM) != 0 &&

      298             c.flatName().toString().startsWith("com.sun.tools.")

      299             // && !Target.class.getSuperclass().getName().equals("java.lang.Enum")

      300             ;

      301     }

      302 

      303     /** In J2SE1.5.0, we introduced the "EnclosingMethod" attribute

      304      *  for improved reflection support.

      305      */

      306     public boolean hasEnclosingMethodAttribute() {

      307         return compareTo(JDK1_5) >= 0 || this == JSR14;

      308     }

      309 }