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    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   }

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