1 /*
  2  * Copyright (c) 1999, 2023, 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 import java.util.stream.Collectors;
 34 
 35 import javax.lang.model.element.Modifier;
 36 
 37 import com.sun.tools.javac.util.Assert;
 38 import com.sun.tools.javac.util.StringUtils;
 39 
 40 /** Access flags and other modifiers for Java classes and members.
 41  *
 42  *  <p><b>This is NOT part of any supported API.
 43  *  If you write code that depends on this, you do so at your own risk.
 44  *  This code and its internal interfaces are subject to change or
 45  *  deletion without notice.</b>
 46  */
 47 public class Flags {
 48 
 49     private Flags() {} // uninstantiable
 50 
 51     public static String toString(long flags) {
 52         StringBuilder buf = new StringBuilder();
 53         String sep = "";
 54         for (Flag flag : asFlagSet(flags)) {
 55             buf.append(sep);
 56             buf.append(flag);
 57             sep = " ";
 58         }
 59         return buf.toString();
 60     }
 61 
 62     public static EnumSet<Flag> asFlagSet(long flags) {
 63         EnumSet<Flag> flagSet = EnumSet.noneOf(Flag.class);
 64         for (Flag flag : Flag.values()) {
 65             if ((flags & flag.value) != 0) {
 66                 flagSet.add(flag);
 67                 flags &= ~flag.value;
 68             }
 69         }
 70         Assert.check(flags == 0);
 71         return flagSet;
 72     }
 73 
 74     /* Standard Java flags.
 75      */
 76     public static final int PUBLIC       = 1;
 77     public static final int PRIVATE      = 1<<1;
 78     public static final int PROTECTED    = 1<<2;
 79     public static final int STATIC       = 1<<3;
 80     public static final int FINAL        = 1<<4;
 81     public static final int SYNCHRONIZED = 1<<5;
 82     public static final int VOLATILE     = 1<<6;
 83     public static final int TRANSIENT    = 1<<7;
 84     public static final int NATIVE       = 1<<8;
 85     public static final int INTERFACE    = 1<<9;
 86     public static final int ABSTRACT     = 1<<10;
 87     public static final int STRICTFP     = 1<<11;
 88 
 89     /* Flag that marks a symbol synthetic, added in classfile v49.0. */
 90     public static final int SYNTHETIC    = 1<<12;
 91 
 92     /** Flag that marks attribute interfaces, added in classfile v49.0. */
 93     public static final int ANNOTATION   = 1<<13;
 94 
 95     /** An enumeration type or an enumeration constant, added in
 96      *  classfile v49.0. */
 97     public static final int ENUM         = 1<<14;
 98 
 99     /** Added in SE8, represents constructs implicitly declared in source. */
100     public static final int MANDATED     = 1<<15;
101 
102     public static final int StandardFlags = 0x0fff;
103 
104     // Because the following access flags are overloaded with other
105     // bit positions, we translate them when reading and writing class
106     // files into unique bits positions: ACC_SYNTHETIC <-> SYNTHETIC,
107     // for example.
108     public static final int ACC_SUPER    = 0x0020;
109     public static final int ACC_BRIDGE   = 0x0040;
110     public static final int ACC_VARARGS  = 0x0080;
111     public static final int ACC_MODULE   = 0x8000;
112 
113     /*****************************************
114      * Internal compiler flags (no bits in the lower 16).
115      *****************************************/
116 
117     /** Flag is set if symbol is deprecated.  See also DEPRECATED_REMOVAL.
118      */
119     public static final int DEPRECATED   = 1<<17;
120 
121     /** Flag is set for a variable symbol if the variable's definition
122      *  has an initializer part.
123      */
124     public static final int HASINIT          = 1<<18;
125 
126     /** Class is a unnamed top level class.
127      */
128     public static final int UNNAMED_CLASS    = 1<<19;
129 
130     /** Flag is set for compiler-generated anonymous method symbols
131      *  that `own' an initializer block.
132      */
133     public static final int BLOCK            = 1<<20;
134 
135     /** Flag is set for ClassSymbols that are being compiled from source.
136      */
137     public static final int FROM_SOURCE      = 1<<21; //ClassSymbols
138 
139     /** Flag is set for nested classes that do not access instance members
140      *  or `this' of an outer class and therefore don't need to be passed
141      *  a this$n reference.  This value is currently set only for anonymous
142      *  classes in superclass constructor calls.
143      *  todo: use this value for optimizing away this$n parameters in
144      *  other cases.
145      */
146     public static final int NOOUTERTHIS  = 1<<22;
147 
148     /** Flag is set for package symbols if a package has a member or
149      *  directory and therefore exists.
150      */
151     public static final int EXISTS           = 1<<23;
152 
153     /** Flag is set for compiler-generated compound classes
154      *  representing multiple variable bounds
155      */
156     public static final int COMPOUND     = 1<<24;
157 
158     /** Flag is set for class symbols if a class file was found for this class.
159      */
160     public static final int CLASS_SEEN   = 1<<25;
161 
162     /** Flag is set for class symbols if a source file was found for this
163      *  class.
164      */
165     public static final int SOURCE_SEEN  = 1<<26;
166 
167     /* State flags (are reset during compilation).
168      */
169 
170     /** Flag for class symbols is set and later re-set as a lock in
171      *  Enter to detect cycles in the superclass/superinterface
172      *  relations.  Similarly for constructor call cycle detection in
173      *  Attr.
174      */
175     public static final int LOCKED           = 1<<27;
176 
177     /** Flag for class symbols is set and later re-set to indicate that a class
178      *  has been entered but has not yet been attributed.
179      */
180     public static final int UNATTRIBUTED = 1<<28;
181 
182     /** Flag for synthesized default constructors of anonymous classes.
183      */
184     public static final int ANONCONSTR   = 1<<29; //non-class members
185 
186     /**
187      * Flag to indicate the superclasses of this ClassSymbol has been attributed.
188      */
189     public static final int SUPER_OWNER_ATTRIBUTED = 1<<29; //ClassSymbols
190 
191     /** Flag for class symbols to indicate it has been checked and found
192      *  acyclic.
193      */
194     public static final int ACYCLIC          = 1<<30;
195 
196     /** Flag that marks bridge methods.
197      */
198     public static final long BRIDGE          = 1L<<31;
199 
200     /** Flag that marks formal parameters.
201      */
202     public static final long PARAMETER   = 1L<<33;
203 
204     /** Flag that marks varargs methods.
205      */
206     public static final long VARARGS   = 1L<<34;
207 
208     /** Flag for annotation type symbols to indicate it has been
209      *  checked and found acyclic.
210      */
211     public static final long ACYCLIC_ANN      = 1L<<35;
212 
213     /** Flag that marks a generated default constructor.
214      */
215     public static final long GENERATEDCONSTR   = 1L<<36;
216 
217     /** Flag that marks a hypothetical method that need not really be
218      *  generated in the binary, but is present in the symbol table to
219      *  simplify checking for erasure clashes - also used for 292 poly sig methods.
220      */
221     public static final long HYPOTHETICAL   = 1L<<37;
222 
223     /**
224      * Flag that marks an internal proprietary class.
225      */
226     public static final long PROPRIETARY = 1L<<38;
227 
228     /**
229      * Flag that marks a multi-catch parameter.
230      */
231     public static final long UNION = 1L<<39;
232 
233     /**
234      * Flags an erroneous TypeSymbol as viable for recovery.
235      * TypeSymbols only.
236      */
237     public static final long RECOVERABLE = 1L<<40;
238 
239     /**
240      * Flag that marks an 'effectively final' local variable.
241      */
242     public static final long EFFECTIVELY_FINAL = 1L<<41;
243 
244     /**
245      * Flag that marks non-override equivalent methods with the same signature,
246      * or a conflicting match binding (BindingSymbol).
247      */
248     public static final long CLASH = 1L<<42;
249 
250     /**
251      * Flag that marks either a default method or an interface containing default methods.
252      */
253     public static final long DEFAULT = 1L<<43;
254 
255     /**
256      * Flag that marks class as auxiliary, ie a non-public class following
257      * the public class in a source file, that could block implicit compilation.
258      */
259     public static final long AUXILIARY = 1L<<44;
260 
261     /**
262      * Flag that marks that a symbol is not available in the current profile
263      */
264     public static final long NOT_IN_PROFILE = 1L<<45;
265 
266     /**
267      * Flag that indicates that an override error has been detected by Check.
268      */
269     public static final long BAD_OVERRIDE = 1L<<45;
270 
271     /**
272      * Flag that indicates a signature polymorphic method (292).
273      */
274     public static final long SIGNATURE_POLYMORPHIC = 1L<<46;
275 
276     /**
277      * Flag that indicates that an inference variable is used in a 'throws' clause.
278      */
279     public static final long THROWS = 1L<<47;
280 
281     /**
282      * Currently available: Bit 48.
283      */
284 
285     /**
286      * Flag that marks a synthetic method body for a lambda expression
287      */
288     public static final long LAMBDA_METHOD = 1L<<49;
289 
290     /**
291      * Flag to control recursion in TransTypes
292      */
293     public static final long TYPE_TRANSLATED = 1L<<50;
294 
295     /**
296      * Flag to indicate class symbol is for module-info
297      */
298     public static final long MODULE = 1L<<51;
299 
300     /**
301      * Flag to indicate the given ModuleSymbol is an automatic module.
302      */
303     public static final long AUTOMATIC_MODULE = 1L<<52; //ModuleSymbols only
304 
305     /**
306      * Flag to indicate the given PackageSymbol contains any non-.java and non-.class resources.
307      */
308     public static final long HAS_RESOURCE = 1L<<52; //PackageSymbols only
309 
310     /**
311      * Flag to indicate the given ParamSymbol has a user-friendly name filled.
312      */
313     public static final long NAME_FILLED = 1L<<52; //ParamSymbols only
314 
315     /**
316      * Flag to indicate the given ModuleSymbol is a system module.
317      */
318     public static final long SYSTEM_MODULE = 1L<<53; //ModuleSymbols only
319 
320     /**
321      * Flag to indicate the given ClassSymbol is a value based.
322      */
323     public static final long VALUE_BASED = 1L<<53; //ClassSymbols only
324 
325     /**
326      * Flag to indicate the given symbol has a @Deprecated annotation.
327      */
328     public static final long DEPRECATED_ANNOTATION = 1L<<54;
329 
330     /**
331      * Flag to indicate the given symbol has been deprecated and marked for removal.
332      */
333     public static final long DEPRECATED_REMOVAL = 1L<<55;
334 
335     /**
336      * Flag to indicate the API element in question is for a preview API.
337      */
338     public static final long PREVIEW_API = 1L<<56; //any Symbol kind
339 
340     /**
341      * Flag for synthesized default constructors of anonymous classes that have an enclosing expression.
342      */
343     public static final long ANONCONSTR_BASED = 1L<<57;
344 
345     /**
346      * Flag that marks finalize block as body-only, should not be copied into catch clauses.
347      * Used to implement try-with-resources.
348      */
349     public static final long BODY_ONLY_FINALIZE = 1L<<17; //blocks only
350 
351     /**
352      * Flag to indicate the API element in question is for a preview API.
353      */
354     public static final long PREVIEW_REFLECTIVE = 1L<<58; //any Symbol kind
355 
356     /**
357      * Flag to indicate the given variable is a match binding variable.
358      */
359     public static final long MATCH_BINDING = 1L<<59;
360 
361     /**
362      * A flag to indicate a match binding variable whose scope extends after the current statement.
363      */
364     public static final long MATCH_BINDING_TO_OUTER = 1L<<60;
365 
366     /**
367      * Flag to indicate that a class is a record. The flag is also used to mark fields that are
368      * part of the state vector of a record and to mark the canonical constructor
369      */
370     public static final long RECORD = 1L<<61; // ClassSymbols, MethodSymbols and VarSymbols
371 
372     /**
373      * Flag to mark a record constructor as a compact one
374      */
375     public static final long COMPACT_RECORD_CONSTRUCTOR = 1L<<51; // MethodSymbols only
376 
377     /**
378      * Flag to mark a record field that was not initialized in the compact constructor
379      */
380     public static final long UNINITIALIZED_FIELD= 1L<<51; // VarSymbols only
381 
382     /** Flag is set for compiler-generated record members, it could be applied to
383      *  accessors and fields
384      */
385     public static final int GENERATED_MEMBER = 1<<24; // MethodSymbols and VarSymbols
386 
387     /**
388      * Flag to indicate sealed class/interface declaration.
389      */
390     public static final long SEALED = 1L<<62; // ClassSymbols
391 
392     /**
393      * Flag to indicate restricted method declaration.
394      */
395     public static final long RESTRICTED = 1L<<62; // MethodSymbols
396 
397     /**
398      * Flag to indicate that the class/interface was declared with the non-sealed modifier.
399      */
400     public static final long NON_SEALED = 1L<<63; // ClassSymbols
401 
402     /**
403      * Describe modifier flags as they might appear in source code, i.e.,
404      * separated by spaces and in the order suggested by JLS 8.1.1.
405      */
406     public static String toSource(long flags) {
407         return asModifierSet(flags).stream()
408           .map(Modifier::toString)
409           .collect(Collectors.joining(" "));
410     }
411 
412     /** Modifier masks.
413      */
414     public static final int
415         AccessFlags                       = PUBLIC | PROTECTED | PRIVATE,
416         LocalClassFlags                   = FINAL | ABSTRACT | STRICTFP | ENUM | SYNTHETIC,
417         StaticLocalFlags                  = LocalClassFlags | STATIC | INTERFACE,
418         MemberClassFlags                  = LocalClassFlags | INTERFACE | AccessFlags,
419         MemberStaticClassFlags            = MemberClassFlags | STATIC,
420         ClassFlags                        = LocalClassFlags | INTERFACE | PUBLIC | ANNOTATION,
421         InterfaceVarFlags                 = FINAL | STATIC | PUBLIC,
422         VarFlags                          = AccessFlags | FINAL | STATIC |
423                                             VOLATILE | TRANSIENT | ENUM,
424         ConstructorFlags                  = AccessFlags,
425         InterfaceMethodFlags              = ABSTRACT | PUBLIC,
426         MethodFlags                       = AccessFlags | ABSTRACT | STATIC | NATIVE |
427                                             SYNCHRONIZED | FINAL | STRICTFP,
428         RecordMethodFlags                 = AccessFlags | ABSTRACT | STATIC |
429                                             SYNCHRONIZED | FINAL | STRICTFP;
430     public static final long
431         ExtendedStandardFlags             = (long)StandardFlags | DEFAULT | SEALED | NON_SEALED,
432         ExtendedMemberClassFlags          = (long)MemberClassFlags | SEALED | NON_SEALED,
433         ExtendedMemberStaticClassFlags    = (long) MemberStaticClassFlags | SEALED | NON_SEALED,
434         ExtendedClassFlags                = (long)ClassFlags | SEALED | NON_SEALED,
435         ModifierFlags                     = ((long)StandardFlags & ~INTERFACE) | DEFAULT | SEALED | NON_SEALED,
436         InterfaceMethodMask               = ABSTRACT | PRIVATE | STATIC | PUBLIC | STRICTFP | DEFAULT,
437         AnnotationTypeElementMask         = ABSTRACT | PUBLIC,
438         LocalVarFlags                     = FINAL | PARAMETER,
439         ReceiverParamFlags                = PARAMETER;
440 
441     public static Set<Modifier> asModifierSet(long flags) {
442         Set<Modifier> modifiers = modifierSets.get(flags);
443         if (modifiers == null) {
444             modifiers = java.util.EnumSet.noneOf(Modifier.class);
445             if (0 != (flags & PUBLIC))    modifiers.add(Modifier.PUBLIC);
446             if (0 != (flags & PROTECTED)) modifiers.add(Modifier.PROTECTED);
447             if (0 != (flags & PRIVATE))   modifiers.add(Modifier.PRIVATE);
448             if (0 != (flags & ABSTRACT))  modifiers.add(Modifier.ABSTRACT);
449             if (0 != (flags & STATIC))    modifiers.add(Modifier.STATIC);
450             if (0 != (flags & SEALED))    modifiers.add(Modifier.SEALED);
451             if (0 != (flags & NON_SEALED))
452                                           modifiers.add(Modifier.NON_SEALED);
453             if (0 != (flags & FINAL))     modifiers.add(Modifier.FINAL);
454             if (0 != (flags & TRANSIENT)) modifiers.add(Modifier.TRANSIENT);
455             if (0 != (flags & VOLATILE))  modifiers.add(Modifier.VOLATILE);
456             if (0 != (flags & SYNCHRONIZED))
457                                           modifiers.add(Modifier.SYNCHRONIZED);
458             if (0 != (flags & NATIVE))    modifiers.add(Modifier.NATIVE);
459             if (0 != (flags & STRICTFP))  modifiers.add(Modifier.STRICTFP);
460             if (0 != (flags & DEFAULT))   modifiers.add(Modifier.DEFAULT);
461             modifiers = Collections.unmodifiableSet(modifiers);
462             modifierSets.put(flags, modifiers);
463         }
464         return modifiers;
465     }
466 
467     // Cache of modifier sets.
468     private static final Map<Long, Set<Modifier>> modifierSets = new ConcurrentHashMap<>(64);
469 
470     public static boolean isStatic(Symbol symbol) {
471         return (symbol.flags() & STATIC) != 0;
472     }
473 
474     public static boolean isEnum(Symbol symbol) {
475         return (symbol.flags() & ENUM) != 0;
476     }
477 
478     public static boolean isConstant(Symbol.VarSymbol symbol) {
479         return symbol.getConstValue() != null;
480     }
481 
482 
483     public enum Flag {
484         PUBLIC(Flags.PUBLIC),
485         PRIVATE(Flags.PRIVATE),
486         PROTECTED(Flags.PROTECTED),
487         STATIC(Flags.STATIC),
488         FINAL(Flags.FINAL),
489         SYNCHRONIZED(Flags.SYNCHRONIZED),
490         VOLATILE(Flags.VOLATILE),
491         TRANSIENT(Flags.TRANSIENT),
492         NATIVE(Flags.NATIVE),
493         INTERFACE(Flags.INTERFACE),
494         ABSTRACT(Flags.ABSTRACT),
495         DEFAULT(Flags.DEFAULT),
496         STRICTFP(Flags.STRICTFP),
497         BRIDGE(Flags.BRIDGE),
498         SYNTHETIC(Flags.SYNTHETIC),
499         ANNOTATION(Flags.ANNOTATION),
500         DEPRECATED(Flags.DEPRECATED),
501         HASINIT(Flags.HASINIT),
502         UNNAMED_CLASS(Flags.UNNAMED_CLASS),
503         BLOCK(Flags.BLOCK),
504         FROM_SOURCE(Flags.FROM_SOURCE),
505         ENUM(Flags.ENUM),
506         MANDATED(Flags.MANDATED),
507         NOOUTERTHIS(Flags.NOOUTERTHIS),
508         EXISTS(Flags.EXISTS),
509         COMPOUND(Flags.COMPOUND),
510         CLASS_SEEN(Flags.CLASS_SEEN),
511         SOURCE_SEEN(Flags.SOURCE_SEEN),
512         LOCKED(Flags.LOCKED),
513         UNATTRIBUTED(Flags.UNATTRIBUTED),
514         ANONCONSTR(Flags.ANONCONSTR),
515         ACYCLIC(Flags.ACYCLIC),
516         PARAMETER(Flags.PARAMETER),
517         VARARGS(Flags.VARARGS),
518         ACYCLIC_ANN(Flags.ACYCLIC_ANN),
519         GENERATEDCONSTR(Flags.GENERATEDCONSTR),
520         HYPOTHETICAL(Flags.HYPOTHETICAL),
521         PROPRIETARY(Flags.PROPRIETARY),
522         UNION(Flags.UNION),
523         EFFECTIVELY_FINAL(Flags.EFFECTIVELY_FINAL),
524         CLASH(Flags.CLASH),
525         AUXILIARY(Flags.AUXILIARY),
526         NOT_IN_PROFILE(Flags.NOT_IN_PROFILE),
527         BAD_OVERRIDE(Flags.BAD_OVERRIDE),
528         SIGNATURE_POLYMORPHIC(Flags.SIGNATURE_POLYMORPHIC),
529         THROWS(Flags.THROWS),
530         LAMBDA_METHOD(Flags.LAMBDA_METHOD),
531         TYPE_TRANSLATED(Flags.TYPE_TRANSLATED),
532         MODULE(Flags.MODULE),
533         AUTOMATIC_MODULE(Flags.AUTOMATIC_MODULE),
534         SYSTEM_MODULE(Flags.SYSTEM_MODULE),
535         DEPRECATED_ANNOTATION(Flags.DEPRECATED_ANNOTATION),
536         DEPRECATED_REMOVAL(Flags.DEPRECATED_REMOVAL),
537         HAS_RESOURCE(Flags.HAS_RESOURCE),
538         // Bit 48 is currently available
539         ANONCONSTR_BASED(Flags.ANONCONSTR_BASED),
540         NAME_FILLED(Flags.NAME_FILLED),
541         PREVIEW_API(Flags.PREVIEW_API),
542         PREVIEW_REFLECTIVE(Flags.PREVIEW_REFLECTIVE),
543         MATCH_BINDING(Flags.MATCH_BINDING),
544         MATCH_BINDING_TO_OUTER(Flags.MATCH_BINDING_TO_OUTER),
545         RECORD(Flags.RECORD),
546         RECOVERABLE(Flags.RECOVERABLE),
547         SEALED(Flags.SEALED),
548         NON_SEALED(Flags.NON_SEALED) {
549             @Override
550             public String toString() {
551                 return "non-sealed";
552             }
553         };
554 
555         Flag(long flag) {
556             this.value = flag;
557             this.lowercaseName = StringUtils.toLowerCase(name());
558         }
559 
560         @Override
561         public String toString() {
562             return lowercaseName;
563         }
564 
565         final long value;
566         final String lowercaseName;
567     }
568 
569 }