1 /*
  2  * Copyright (c) 1999, 2021, 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.code;
 27 
 28 import java.util.Collections;
 29 import java.util.EnumSet;
 30 import java.util.Map;
 31 import java.util.Set;
 32 import java.util.concurrent.ConcurrentHashMap;
 33 
 34 import javax.lang.model.element.Modifier;
 35 
 36 import com.sun.tools.javac.util.Assert;
 37 import com.sun.tools.javac.util.StringUtils;
 38 
 39 /** Access flags and other modifiers for Java classes and members.
 40  *
 41  *  <p><b>This is NOT part of any supported API.
 42  *  If you write code that depends on this, you do so at your own risk.
 43  *  This code and its internal interfaces are subject to change or
 44  *  deletion without notice.</b>
 45  */
 46 public class Flags {
 47 
 48     private Flags() {} // uninstantiable
 49 
 50     public static String toString(long flags) {
 51         StringBuilder buf = new StringBuilder();
 52         String sep = "";
 53         for (Flag flag : asFlagSet(flags)) {
 54             buf.append(sep);
 55             buf.append(flag);
 56             sep = " ";
 57         }
 58         return buf.toString();
 59     }
 60 
 61     public static EnumSet<Flag> asFlagSet(long flags) {
 62         EnumSet<Flag> flagSet = EnumSet.noneOf(Flag.class);
 63         for (Flag flag : Flag.values()) {
 64             if ((flags & flag.value) != 0) {
 65                 flagSet.add(flag);
 66                 flags &= ~flag.value;
 67             }
 68         }
 69         Assert.check(flags == 0);
 70         return flagSet;
 71     }
 72 
 73     /* Standard Java flags.
 74      */
 75     public static final int PUBLIC       = 1;
 76     public static final int PRIVATE      = 1<<1;
 77     public static final int PROTECTED    = 1<<2;
 78     public static final int STATIC       = 1<<3;
 79     public static final int FINAL        = 1<<4;
 80     public static final int SYNCHRONIZED = 1<<5;
 81     public static final int VOLATILE     = 1<<6;
 82     public static final int TRANSIENT    = 1<<7;
 83     public static final int NATIVE       = 1<<8;
 84     public static final int INTERFACE    = 1<<9;
 85     public static final int ABSTRACT     = 1<<10;
 86     public static final int STRICTFP     = 1<<11;
 87 
 88     /* Flag that marks a symbol synthetic, added in classfile v49.0. */
 89     public static final int SYNTHETIC    = 1<<12;
 90 
 91     /** Flag that marks attribute interfaces, added in classfile v49.0. */
 92     public static final int ANNOTATION   = 1<<13;
 93 
 94     /** An enumeration type or an enumeration constant, added in
 95      *  classfile v49.0. */
 96     public static final int ENUM         = 1<<14;
 97 
 98     /** Added in SE8, represents constructs implicitly declared in source. */
 99     public static final int MANDATED     = 1<<15;
100 
101     /** Marks a type as a primitive class */
102     public static final int PRIMITIVE_CLASS  = 1<<16;
103 
104     public static final int StandardFlags = 0x0fff;
105 
106     // Because the following access flags are overloaded with other
107     // bit positions, we translate them when reading and writing class
108     // files into unique bits positions: ACC_SYNTHETIC <-> SYNTHETIC,
109     // for example.
110     public static final int ACC_SUPER    = 0x0020;
111     public static final int ACC_BRIDGE   = 0x0040;
112     public static final int ACC_VARARGS  = 0x0080;
113     public static final int ACC_PRIMITIVE = 0x0100;
114     public static final int ACC_MODULE   = 0x8000;
115 
116     /*****************************************
117      * Internal compiler flags (no bits in the lower 16).
118      *****************************************/
119 
120     /** Flag is set if symbol is deprecated.  See also DEPRECATED_REMOVAL.
121      */
122     public static final int DEPRECATED   = 1<<17;
123 
124     /** Flag is set for a variable symbol if the variable's definition
125      *  has an initializer part.
126      */
127     public static final int HASINIT          = 1<<18;
128 
129     /** Flag is set for a class symbol if it defines one or more non-empty
130      *  instance initializer block(s). This is relevenat only for class symbols
131      *  that originate from source types. For binary types the instance initializer
132      *  blocks are "normalized" into the constructors.
133      */
134     public static final int HASINITBLOCK         = 1<<18;
135 
136     /** Flag is set for a method symbol if it is an empty no-arg ctor.
137      *  i.e one that simply returns (jlO) or merely chains to a super's
138      *  EMPTYNOARGCONSTR
139      */
140     public static final int EMPTYNOARGCONSTR         = 1<<18;
141 
142     /**
143      * Flag is set for a reference favoring primitive class.
144      */
145     public static final int REFERENCE_FAVORING          = 1<<19;
146 
147     /** Flag is set for compiler-generated anonymous method symbols
148      *  that `own' an initializer block.
149      */
150     public static final int BLOCK            = 1<<20;
151 
152     /** Flag bit 21 is available. (used earlier to tag compiler-generated abstract methods that implement
153      *  an interface method (Miranda methods)).
154      */
155 
156     /** Flag is set for nested classes that do not access instance members
157      *  or `this' of an outer class and therefore don't need to be passed
158      *  a this$n reference.  This value is currently set only for anonymous
159      *  classes in superclass constructor calls.
160      *  todo: use this value for optimizing away this$n parameters in
161      *  other cases.
162      */
163     public static final int NOOUTERTHIS  = 1<<22;
164 
165     /** Flag is set for package symbols if a package has a member or
166      *  directory and therefore exists.
167      */
168     public static final int EXISTS           = 1<<23;
169 
170     /** Flag is set for compiler-generated compound classes
171      *  representing multiple variable bounds
172      */
173     public static final int COMPOUND     = 1<<24;
174 
175     /** Flag is set for class symbols if a class file was found for this class.
176      */
177     public static final int CLASS_SEEN   = 1<<25;
178 
179     /** Flag is set for class symbols if a source file was found for this
180      *  class.
181      */
182     public static final int SOURCE_SEEN  = 1<<26;
183 
184     /* State flags (are reset during compilation).
185      */
186 
187     /** Flag for class symbols is set and later re-set as a lock in
188      *  Enter to detect cycles in the superclass/superinterface
189      *  relations.  Similarly for constructor call cycle detection in
190      *  Attr.
191      */
192     public static final int LOCKED           = 1<<27;
193 
194     /** Flag for class symbols is set and later re-set to indicate that a class
195      *  has been entered but has not yet been attributed.
196      */
197     public static final int UNATTRIBUTED = 1<<28;
198 
199     /** Flag for synthesized default constructors of anonymous classes.
200      */
201     public static final int ANONCONSTR   = 1<<29; //non-class members
202 
203     /**
204      * Flag to indicate the super classes of this ClassSymbol has been attributed.
205      */
206     public static final int SUPER_OWNER_ATTRIBUTED = 1<<29; //ClassSymbols
207 
208     /** Flag for class symbols to indicate it has been checked and found
209      *  acyclic.
210      */
211     public static final int ACYCLIC          = 1<<30;
212 
213     /** Flag that marks bridge methods.
214      */
215     public static final long BRIDGE          = 1L<<31;
216 
217     /** Flag that marks formal parameters.
218      */
219     public static final long PARAMETER   = 1L<<33;
220 
221     /** Flag that marks varargs methods.
222      */
223     public static final long VARARGS   = 1L<<34;
224 
225     /** Flag for annotation type symbols to indicate it has been
226      *  checked and found acyclic.
227      */
228     public static final long ACYCLIC_ANN      = 1L<<35;
229 
230     /** Flag that marks a generated default constructor.
231      */
232     public static final long GENERATEDCONSTR   = 1L<<36;
233 
234     /** Flag that marks a hypothetical method that need not really be
235      *  generated in the binary, but is present in the symbol table to
236      *  simplify checking for erasure clashes - also used for 292 poly sig methods.
237      */
238     public static final long HYPOTHETICAL   = 1L<<37;
239 
240     /**
241      * Flag that marks an internal proprietary class.
242      */
243     public static final long PROPRIETARY = 1L<<38;
244 
245     /**
246      * Flag that marks a multi-catch parameter.
247      */
248     public static final long UNION = 1L<<39;
249 
250     /**
251      * Flags an erroneous TypeSymbol as viable for recovery.
252      * TypeSymbols only.
253      */
254     public static final long RECOVERABLE = 1L<<40;
255 
256     /**
257      * Flag that marks an 'effectively final' local variable.
258      */
259     public static final long EFFECTIVELY_FINAL = 1L<<41;
260 
261     /**
262      * Flag that marks non-override equivalent methods with the same signature,
263      * or a conflicting match binding (BindingSymbol).
264      */
265     public static final long CLASH = 1L<<42;
266 
267     /**
268      * Flag that marks either a default method or an interface containing default methods.
269      */
270     public static final long DEFAULT = 1L<<43;
271 
272     /**
273      * Flag that marks class as auxiliary, ie a non-public class following
274      * the public class in a source file, that could block implicit compilation.
275      */
276     public static final long AUXILIARY = 1L<<44;
277 
278     /**
279      * Flag that marks that a symbol is not available in the current profile
280      */
281     public static final long NOT_IN_PROFILE = 1L<<45;
282 
283     /**
284      * Flag that indicates that an override error has been detected by Check.
285      */
286     public static final long BAD_OVERRIDE = 1L<<45;
287 
288     /**
289      * Flag that indicates a signature polymorphic method (292).
290      */
291     public static final long SIGNATURE_POLYMORPHIC = 1L<<46;
292 
293     /**
294      * Flag that indicates that an inference variable is used in a 'throws' clause.
295      */
296     public static final long THROWS = 1L<<47;
297 
298     /**
299      * Flag that marks potentially ambiguous overloads
300      */
301     public static final long POTENTIALLY_AMBIGUOUS = 1L<<48;
302 
303     /**
304      * Flag that marks a synthetic method body for a lambda expression
305      */
306     public static final long LAMBDA_METHOD = 1L<<49;
307 
308     /**
309      * Flag to control recursion in TransTypes
310      */
311     public static final long TYPE_TRANSLATED = 1L<<50;
312 
313     /**
314      * Flag to indicate class symbol is for module-info
315      */
316     public static final long MODULE = 1L<<51;
317 
318     /**
319      * Flag to indicate the given ModuleSymbol is an automatic module.
320      */
321     public static final long AUTOMATIC_MODULE = 1L<<52; //ModuleSymbols only
322 
323     /**
324      * Flag to indicate the given PackageSymbol contains any non-.java and non-.class resources.
325      */
326     public static final long HAS_RESOURCE = 1L<<52; //PackageSymbols only
327 
328     /**
329      * Flag to indicate the given ParamSymbol has a user-friendly name filled.
330      */
331     public static final long NAME_FILLED = 1L<<52; //ParamSymbols only
332 
333     /**
334      * Flag to indicate the given ModuleSymbol is a system module.
335      */
336     public static final long SYSTEM_MODULE = 1L<<53; //ModuleSymbols only
337 
338     /**
339      * Flag to indicate the given ClassSymbol is a value based.
340      */
341     public static final long VALUE_BASED = 1L<<53; //ClassSymbols only
342 
343     /**
344      * Flag to indicate the given symbol has a @Deprecated annotation.
345      */
346     public static final long DEPRECATED_ANNOTATION = 1L<<54;
347 
348     /**
349      * Flag to indicate the given symbol has been deprecated and marked for removal.
350      */
351     public static final long DEPRECATED_REMOVAL = 1L<<55;
352 
353     /**
354      * Flag to indicate the API element in question is for a preview API.
355      */
356     public static final long PREVIEW_API = 1L<<56; //any Symbol kind
357 
358     /**
359      * Flag for synthesized default constructors of anonymous classes that have an enclosing expression.
360      */
361     public static final long ANONCONSTR_BASED = 1L<<57;
362 
363     /**
364      * Flag that marks finalize block as body-only, should not be copied into catch clauses.
365      * Used to implement try-with-resources.
366      */
367     public static final long BODY_ONLY_FINALIZE = 1L<<17; //blocks only
368 
369     /**
370      * Flag to indicate the API element in question is for a preview API.
371      */
372     public static final long PREVIEW_REFLECTIVE = 1L<<58; //any Symbol kind
373 
374     /**
375      * Flag to indicate the given variable is a match binding variable.
376      */
377     public static final long MATCH_BINDING = 1L<<59;
378 
379     /**
380      * A flag to indicate a match binding variable whose scope extends after the current statement.
381      */
382     public static final long MATCH_BINDING_TO_OUTER = 1L<<60;
383 
384     /**
385      * Flag to indicate that a class is a record. The flag is also used to mark fields that are
386      * part of the state vector of a record and to mark the canonical constructor
387      */
388     public static final long RECORD = 1L<<61; // ClassSymbols, MethodSymbols and VarSymbols
389 
390     /**
391      * Flag to mark a record constructor as a compact one
392      */
393     public static final long COMPACT_RECORD_CONSTRUCTOR = 1L<<51; // MethodSymbols only
394 
395     /**
396      * Flag to mark a record field that was not initialized in the compact constructor
397      */
398     public static final long UNINITIALIZED_FIELD= 1L<<51; // VarSymbols only
399 
400     /** Flag is set for compiler-generated record members, it could be applied to
401      *  accessors and fields
402      */
403     public static final int GENERATED_MEMBER = 1<<24; // MethodSymbols and VarSymbols
404 
405     /**
406      * Flag to indicate sealed class/interface declaration.
407      */
408     public static final long SEALED = 1L<<62; // ClassSymbols
409 
410     /**
411      * Flag to indicate that the class/interface was declared with the non-sealed modifier.
412      */
413     public static final long NON_SEALED = 1L<<63; // ClassSymbols
414 
415     // Encodings for extended flags stored using attributes
416     /**
417      * Flag to indicate that the primitive class is reference default.
418      */
419     public static final int ACC_REF_DEFAULT = 1;
420 
421     /** Modifier masks.
422      */
423     public static final int
424         AccessFlags                       = PUBLIC | PROTECTED | PRIVATE,
425         LocalClassFlags                   = FINAL | ABSTRACT | STRICTFP | ENUM | SYNTHETIC  | PRIMITIVE_CLASS,
426         StaticLocalFlags                  = LocalClassFlags | STATIC | INTERFACE,
427         MemberClassFlags                  = LocalClassFlags | INTERFACE | AccessFlags,
428         MemberStaticClassFlags            = MemberClassFlags | STATIC,
429         ClassFlags                        = LocalClassFlags | INTERFACE | PUBLIC | ANNOTATION,
430         InterfaceVarFlags                 = FINAL | STATIC | PUBLIC,
431         VarFlags                          = AccessFlags | FINAL | STATIC |
432                                             VOLATILE | TRANSIENT | ENUM,
433         ConstructorFlags                  = AccessFlags,
434         InterfaceMethodFlags              = ABSTRACT | PUBLIC,
435         MethodFlags                       = AccessFlags | ABSTRACT | STATIC | NATIVE |
436                                             SYNCHRONIZED | FINAL | STRICTFP,
437         RecordMethodFlags                 = AccessFlags | ABSTRACT | STATIC |
438                                             SYNCHRONIZED | FINAL | STRICTFP;
439     public static final long
440         ExtendedStandardFlags             = (long)StandardFlags | DEFAULT | SEALED | NON_SEALED | PRIMITIVE_CLASS,
441         ExtendedMemberClassFlags          = (long)MemberClassFlags | SEALED | NON_SEALED,
442         ExtendedMemberStaticClassFlags    = (long) MemberStaticClassFlags | SEALED | NON_SEALED,
443         ExtendedClassFlags                = (long)ClassFlags | SEALED | NON_SEALED,
444         ModifierFlags                     = ((long)StandardFlags & ~INTERFACE) | DEFAULT | SEALED | NON_SEALED,
445         InterfaceMethodMask               = ABSTRACT | PRIVATE | STATIC | PUBLIC | STRICTFP | DEFAULT,
446         AnnotationTypeElementMask         = ABSTRACT | PUBLIC,
447         LocalVarFlags                     = FINAL | PARAMETER,
448         ReceiverParamFlags                = PARAMETER;
449 
450     public static Set<Modifier> asModifierSet(long flags) {
451         Set<Modifier> modifiers = modifierSets.get(flags);
452         if (modifiers == null) {
453             modifiers = java.util.EnumSet.noneOf(Modifier.class);
454             if (0 != (flags & PUBLIC))    modifiers.add(Modifier.PUBLIC);
455             if (0 != (flags & PROTECTED)) modifiers.add(Modifier.PROTECTED);
456             if (0 != (flags & PRIVATE))   modifiers.add(Modifier.PRIVATE);
457             if (0 != (flags & ABSTRACT))  modifiers.add(Modifier.ABSTRACT);
458             if (0 != (flags & STATIC))    modifiers.add(Modifier.STATIC);
459             if (0 != (flags & SEALED))    modifiers.add(Modifier.SEALED);
460             if (0 != (flags & NON_SEALED))
461                                           modifiers.add(Modifier.NON_SEALED);
462             if (0 != (flags & FINAL))     modifiers.add(Modifier.FINAL);
463             if (0 != (flags & TRANSIENT)) modifiers.add(Modifier.TRANSIENT);
464             if (0 != (flags & VOLATILE))  modifiers.add(Modifier.VOLATILE);
465             if (0 != (flags & SYNCHRONIZED))
466                                           modifiers.add(Modifier.SYNCHRONIZED);
467             if (0 != (flags & NATIVE))    modifiers.add(Modifier.NATIVE);
468             if (0 != (flags & STRICTFP))  modifiers.add(Modifier.STRICTFP);
469             if (0 != (flags & DEFAULT))   modifiers.add(Modifier.DEFAULT);
470             if (0 != (flags & PRIMITIVE_CLASS))     modifiers.add(Modifier.PRIMITIVE);
471             modifiers = Collections.unmodifiableSet(modifiers);
472             modifierSets.put(flags, modifiers);
473         }
474         return modifiers;
475     }
476 
477     // Cache of modifier sets.
478     private static final Map<Long, Set<Modifier>> modifierSets = new ConcurrentHashMap<>(64);
479 
480     public static boolean isStatic(Symbol symbol) {
481         return (symbol.flags() & STATIC) != 0;
482     }
483 
484     public static boolean isEnum(Symbol symbol) {
485         return (symbol.flags() & ENUM) != 0;
486     }
487 
488     public static boolean isConstant(Symbol.VarSymbol symbol) {
489         return symbol.getConstValue() != null;
490     }
491 
492 
493     public enum Flag {
494         PUBLIC(Flags.PUBLIC),
495         PRIVATE(Flags.PRIVATE),
496         PROTECTED(Flags.PROTECTED),
497         STATIC(Flags.STATIC),
498         FINAL(Flags.FINAL),
499         SYNCHRONIZED(Flags.SYNCHRONIZED),
500         VOLATILE(Flags.VOLATILE),
501         TRANSIENT(Flags.TRANSIENT),
502         NATIVE(Flags.NATIVE),
503         INTERFACE(Flags.INTERFACE),
504         ABSTRACT(Flags.ABSTRACT),
505         DEFAULT(Flags.DEFAULT),
506         STRICTFP(Flags.STRICTFP),
507         BRIDGE(Flags.BRIDGE),
508         SYNTHETIC(Flags.SYNTHETIC),
509         ANNOTATION(Flags.ANNOTATION),
510         DEPRECATED(Flags.DEPRECATED),
511         HASINIT(Flags.HASINIT),
512         HASINITBLOCK(Flags.HASINITBLOCK),
513         EMPTYNOARGCONSTR(Flags.EMPTYNOARGCONSTR),
514         REFERENCE_FAVORING(Flags.REFERENCE_FAVORING),
515         BLOCK(Flags.BLOCK),
516         ENUM(Flags.ENUM),
517         MANDATED(Flags.MANDATED),
518         PRIMITIVE(Flags.PRIMITIVE_CLASS),
519         NOOUTERTHIS(Flags.NOOUTERTHIS),
520         EXISTS(Flags.EXISTS),
521         COMPOUND(Flags.COMPOUND),
522         CLASS_SEEN(Flags.CLASS_SEEN),
523         SOURCE_SEEN(Flags.SOURCE_SEEN),
524         LOCKED(Flags.LOCKED),
525         UNATTRIBUTED(Flags.UNATTRIBUTED),
526         ANONCONSTR(Flags.ANONCONSTR),
527         ACYCLIC(Flags.ACYCLIC),
528         PARAMETER(Flags.PARAMETER),
529         VARARGS(Flags.VARARGS),
530         ACYCLIC_ANN(Flags.ACYCLIC_ANN),
531         GENERATEDCONSTR(Flags.GENERATEDCONSTR),
532         HYPOTHETICAL(Flags.HYPOTHETICAL),
533         PROPRIETARY(Flags.PROPRIETARY),
534         UNION(Flags.UNION),
535         EFFECTIVELY_FINAL(Flags.EFFECTIVELY_FINAL),
536         CLASH(Flags.CLASH),
537         AUXILIARY(Flags.AUXILIARY),
538         NOT_IN_PROFILE(Flags.NOT_IN_PROFILE),
539         BAD_OVERRIDE(Flags.BAD_OVERRIDE),
540         SIGNATURE_POLYMORPHIC(Flags.SIGNATURE_POLYMORPHIC),
541         THROWS(Flags.THROWS),
542         LAMBDA_METHOD(Flags.LAMBDA_METHOD),
543         TYPE_TRANSLATED(Flags.TYPE_TRANSLATED),
544         MODULE(Flags.MODULE),
545         AUTOMATIC_MODULE(Flags.AUTOMATIC_MODULE),
546         SYSTEM_MODULE(Flags.SYSTEM_MODULE),
547         DEPRECATED_ANNOTATION(Flags.DEPRECATED_ANNOTATION),
548         DEPRECATED_REMOVAL(Flags.DEPRECATED_REMOVAL),
549         HAS_RESOURCE(Flags.HAS_RESOURCE),
550         POTENTIALLY_AMBIGUOUS(Flags.POTENTIALLY_AMBIGUOUS),
551         ANONCONSTR_BASED(Flags.ANONCONSTR_BASED),
552         NAME_FILLED(Flags.NAME_FILLED),
553         PREVIEW_API(Flags.PREVIEW_API),
554         PREVIEW_REFLECTIVE(Flags.PREVIEW_REFLECTIVE),
555         MATCH_BINDING(Flags.MATCH_BINDING),
556         MATCH_BINDING_TO_OUTER(Flags.MATCH_BINDING_TO_OUTER),
557         RECORD(Flags.RECORD),
558         RECOVERABLE(Flags.RECOVERABLE),
559         SEALED(Flags.SEALED),
560         NON_SEALED(Flags.NON_SEALED) {
561             @Override
562             public String toString() {
563                 return "non-sealed";
564             }
565         };
566 
567         Flag(long flag) {
568             this.value = flag;
569             this.lowercaseName = StringUtils.toLowerCase(name());
570         }
571 
572         @Override
573         public String toString() {
574             return lowercaseName;
575         }
576 
577         final long value;
578         final String lowercaseName;
579     }
580 
581 }