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 * Copyright (c) 2002, 2006, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

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

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.tools.javac.jvm;

import java.util.*;

import com.sun.tools.javac.code.Flags;

import com.sun.tools.javac.code.Symbol;

import com.sun.tools.javac.util.*;

/** The classfile version target.

 *

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

 *  deletion without notice.</b>

 */

public enum Target {

    JDK1_1("1.1", 45, 3),

    JDK1_2("1.2", 46, 0),

    JDK1_3("1.3", 47, 0),

    /** J2SE1.4 = Merlin. */

    JDK1_4("1.4", 48, 0),

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

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

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

    JSR14("jsr14", 48, 0),

    /** The following are undocumented transitional targets that we

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

     *  promise to retain support for them.  */

    JDK1_4_1("1.4.1", 48, 0),

    JDK1_4_2("1.4.2", 48, 0),

    /** Tiger. */

    JDK1_5("1.5", 49, 0),

    /** JDK 6. */

    JDK1_6("1.6", 50, 0),

    /** JDK 7. */

    JDK1_7("1.7", 51, 0);

    private static final Context.Key<Target> targetKey =

        new Context.Key<Target>();

    public static Target instance(Context context) {

        Target instance = context.get(targetKey);

        if (instance == null) {

            Options options = Options.instance(context);

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

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

            if (instance == null) instance = DEFAULT;

            context.put(targetKey, instance);

        }

        return instance;

    }

    private static Target MIN;

    public static Target MIN() { return MIN; }

    private static Target MAX;

    public static Target MAX() { return MAX; }

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

    static {

        for (Target t : values()) {

            if (MIN == null) MIN = t;

            MAX = t;

            tab.put(t.name, t);

        }

        tab.put("5", JDK1_5);

        tab.put("6", JDK1_6);

        tab.put("7", JDK1_7);

    }

    public final String name;

    public final int majorVersion;

    public final int minorVersion;

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

        this.name = name;

        this.majorVersion = majorVersion;

        this.minorVersion = minorVersion;

    }

    public static final Target DEFAULT = JDK1_7;

    public static Target lookup(String name) {

        return tab.get(name);

    }

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

     *  synthetic method definitions in abstract classes for interface

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

     */

    public boolean requiresIproxy() {

        return compareTo(JDK1_1) <= 0;

    }

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

     *  code to initialize fields before calling the superclass constructor.

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

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

     *  inner classes.  See, for example, 4030374.

     */

    public boolean initializeFieldsBeforeSuper() {

        return compareTo(JDK1_4) >= 0;

    }

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

     *  compatibility, emitting as the qualifying type of a reference

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

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

     *  member was found.  The following methods named

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

     *  general rule. */

    public boolean obeyBinaryCompatibility() {

        return compareTo(JDK1_2) >= 0;

    }

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

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

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

     *  qualified them by Object.

     */

    public boolean arrayBinaryCompatibility() {

        return compareTo(JDK1_5) >= 0;

    }

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

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

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

     *  an accommodation to them.

     */

    public boolean interfaceFieldsBinaryCompatibility() {

        return compareTo(JDK1_2) > 0;

    }

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

     *  rules for interface methods that redefine Object methods.

     *  Earlier VMs had bugs handling such methods compiled using binary

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

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

     */

    public boolean interfaceObjectOverridesBinaryCompatibility() {

        return compareTo(JDK1_5) >= 0;

    }

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

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

     *  necessity of access methods, which effectively relax the

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

     *  execution.

     */

    public boolean usePrivateSyntheticFields() {

        return compareTo(JDK1_4_2) < 0;

    }

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

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

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

     *  using the outermost class.  See 4401576.

     */

    public boolean useInnerCacheClass() {

        return compareTo(JDK1_4_2) >= 0;

    }

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

    public boolean generateCLDCStackmap() {

        return false;

    }

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

     *  compact format. */

    public boolean generateStackMapTable() {

        return compareTo(JDK1_6) >= 0;

    }

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

     */

    public boolean isPackageInfoSynthetic() {

        return compareTo(JDK1_6) >= 0;

    }

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

     */

    public boolean generateEmptyAfterBig() {

        return false;

    }

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

     *  StringBuffer called StringBuilder that can be used by the

     *  compiler for string concatenation.

     */

    public boolean useStringBuilder() {

        return compareTo(JDK1_5) >= 0;

    }

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

     *  marker attributes.

     */

    public boolean useSyntheticFlag() {

        return compareTo(JDK1_5) >= 0;

    }

    public boolean useEnumFlag() {

        return compareTo(JDK1_5) >= 0;

    }

    public boolean useAnnotationFlag() {

        return compareTo(JDK1_5) >= 0;

    }

    public boolean useVarargsFlag() {

        return compareTo(JDK1_5) >= 0;

    }

    public boolean useBridgeFlag() {

        return compareTo(JDK1_5) >= 0;

    }

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

     *  identifiers, where not specified by the JLS.

     */

    public char syntheticNameChar() {

        return '$';

    }

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

     */

    public boolean hasClassLiterals() {

        return compareTo(JDK1_5) >= 0;

    }

    /** Does the VM support an invokedynamic instruction?

     */

    public boolean hasInvokedynamic() {

        return compareTo(JDK1_7) >= 0;

    }

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

     *  avoid initializing the class that the literal refers to?

     *  See 4468823

     */

    public boolean classLiteralsNoInit() {

        return compareTo(JDK1_4_2) >= 0;

    }

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

     *  throw a NoClassDefFoundError, should we initialize its cause?

     */

    public boolean hasInitCause() {

        return compareTo(JDK1_4) >= 0;

    }

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

     *  to implement boxing.

     */

    public boolean boxWithConstructors() {

        return compareTo(JDK1_5) < 0;

    }

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

     *  instead of java.lang.Iterable.

     */

    public boolean hasIterable() {

        return compareTo(JDK1_5) >= 0;

    }

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

     *  necessary.

     */

    public boolean compilerBootstrap(Symbol c) {

        return

            this == JSR14 &&

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

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

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

            ;

    }

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

     *  for improved reflection support.

     */

    public boolean hasEnclosingMethodAttribute() {

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

    }

}