1 /*
   2  * Copyright (c) 1999, 2018, 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.Collection;
  29 import java.util.Collections;
  30 import java.util.EnumSet;
  31 import java.util.HashMap;
  32 import java.util.LinkedHashMap;
  33 import java.util.Map;
  34 
  35 import javax.lang.model.element.ElementVisitor;
  36 
  37 import com.sun.tools.javac.code.Scope.WriteableScope;
  38 import com.sun.tools.javac.code.Source.Feature;
  39 import com.sun.tools.javac.code.Symbol.ClassSymbol;
  40 import com.sun.tools.javac.code.Symbol.Completer;
  41 import com.sun.tools.javac.code.Symbol.CompletionFailure;
  42 import com.sun.tools.javac.code.Symbol.MethodSymbol;
  43 import com.sun.tools.javac.code.Symbol.ModuleSymbol;
  44 import com.sun.tools.javac.code.Symbol.PackageSymbol;
  45 import com.sun.tools.javac.code.Symbol.TypeSymbol;
  46 import com.sun.tools.javac.code.Symbol.VarSymbol;
  47 import com.sun.tools.javac.code.Type.BottomType;
  48 import com.sun.tools.javac.code.Type.ClassType;
  49 import com.sun.tools.javac.code.Type.ErrorType;
  50 import com.sun.tools.javac.code.Type.JCPrimitiveType;
  51 import com.sun.tools.javac.code.Type.JCVoidType;
  52 import com.sun.tools.javac.code.Type.MethodType;
  53 import com.sun.tools.javac.code.Type.UnknownType;
  54 import com.sun.tools.javac.code.Types.UniqueType;
  55 import com.sun.tools.javac.comp.Modules;
  56 import com.sun.tools.javac.util.Assert;
  57 import com.sun.tools.javac.util.Context;
  58 import com.sun.tools.javac.util.Convert;
  59 import com.sun.tools.javac.util.DefinedBy;
  60 import com.sun.tools.javac.util.DefinedBy.Api;
  61 import com.sun.tools.javac.util.Iterators;
  62 import com.sun.tools.javac.util.JavacMessages;
  63 import com.sun.tools.javac.util.List;
  64 import com.sun.tools.javac.util.Name;
  65 import com.sun.tools.javac.util.Names;
  66 
  67 import static com.sun.tools.javac.code.Flags.*;
  68 import static com.sun.tools.javac.code.Kinds.Kind.*;
  69 import static com.sun.tools.javac.code.TypeTag.*;
  70 
  71 /** A class that defines all predefined constants and operators
  72  *  as well as special classes such as java.lang.Object, which need
  73  *  to be known to the compiler. All symbols are held in instance
  74  *  fields. This makes it possible to work in multiple concurrent
  75  *  projects, which might use different class files for library classes.
  76  *
  77  *  <p><b>This is NOT part of any supported API.
  78  *  If you write code that depends on this, you do so at your own risk.
  79  *  This code and its internal interfaces are subject to change or
  80  *  deletion without notice.</b>
  81  */
  82 public class Symtab {
  83     /** The context key for the symbol table. */
  84     protected static final Context.Key<Symtab> symtabKey = new Context.Key<>();
  85 
  86     /** Get the symbol table instance. */
  87     public static Symtab instance(Context context) {
  88         Symtab instance = context.get(symtabKey);
  89         if (instance == null)
  90             instance = new Symtab(context);
  91         return instance;
  92     }
  93 
  94     /** Builtin types.
  95      */
  96     public final JCPrimitiveType byteType = new JCPrimitiveType(BYTE, null);
  97     public final JCPrimitiveType charType = new JCPrimitiveType(CHAR, null);
  98     public final JCPrimitiveType shortType = new JCPrimitiveType(SHORT, null);
  99     public final JCPrimitiveType intType = new JCPrimitiveType(INT, null);
 100     public final JCPrimitiveType longType = new JCPrimitiveType(LONG, null);
 101     public final JCPrimitiveType floatType = new JCPrimitiveType(FLOAT, null);
 102     public final JCPrimitiveType doubleType = new JCPrimitiveType(DOUBLE, null);
 103     public final JCPrimitiveType booleanType = new JCPrimitiveType(BOOLEAN, null);
 104     public final Type botType = new BottomType();
 105     public final JCVoidType voidType = new JCVoidType();
 106 
 107     private final Names names;
 108     private final JavacMessages messages;
 109     private final Completer initialCompleter;
 110     private final Completer moduleCompleter;
 111 
 112     /** A symbol for the unnamed module.
 113      */
 114     public final ModuleSymbol unnamedModule;
 115 
 116     /** The error module.
 117      */
 118     public final ModuleSymbol errModule;
 119 
 120     /** A symbol for no module, for use with -source 8 or less
 121      */
 122     public final ModuleSymbol noModule;
 123 
 124     /** A symbol for the root package.
 125      */
 126     public final PackageSymbol rootPackage;
 127 
 128     /** A symbol that stands for a missing symbol.
 129      */
 130     public final TypeSymbol noSymbol;
 131 
 132     /** The error symbol.
 133      */
 134     public final ClassSymbol errSymbol;
 135 
 136     /** The unknown symbol.
 137      */
 138     public final ClassSymbol unknownSymbol;
 139 
 140     /** A value for the errType, with a originalType of noType */
 141     public final Type errType;
 142 
 143     /** A value for the unknown type. */
 144     public final Type unknownType;
 145 
 146     /** The builtin type of all arrays. */
 147     public final ClassSymbol arrayClass;
 148     public final MethodSymbol arrayCloneMethod;
 149 
 150     /** VGJ: The (singleton) type of all bound types. */
 151     public final ClassSymbol boundClass;
 152 
 153     /** The builtin type of all methods. */
 154     public final ClassSymbol methodClass;
 155 
 156     /** A symbol for the java.base module.
 157      */
 158     public final ModuleSymbol java_base;
 159 
 160     /** Predefined types.
 161      */
 162     public final Type objectType;
 163     public final Type objectsType;
 164     public final Type classType;
 165     public final Type classLoaderType;
 166     public final Type stringType;
 167     public final Type stringBufferType;
 168     public final Type stringBuilderType;
 169     public final Type cloneableType;
 170     public final Type serializableType;
 171     public final Type serializedLambdaType;
 172     public final Type varHandleType;
 173     public final Type methodHandleType;
 174     public final Type methodHandleLookupType;
 175     public final Type methodTypeType;
 176     public final Type nativeHeaderType;
 177     public final Type throwableType;
 178     public final Type errorType;
 179     public final Type interruptedExceptionType;
 180     public final Type illegalArgumentExceptionType;
 181     public final Type exceptionType;
 182     public final Type runtimeExceptionType;
 183     public final Type classNotFoundExceptionType;
 184     public final Type noClassDefFoundErrorType;
 185     public final Type noSuchFieldErrorType;
 186     public final Type assertionErrorType;
 187     public final Type incompatibleClassChangeErrorType;
 188     public final Type cloneNotSupportedExceptionType;
 189     public final Type annotationType;
 190     public final TypeSymbol enumSym;
 191     public final Type listType;
 192     public final Type collectionsType;
 193     public final Type comparableType;
 194     public final Type comparatorType;
 195     public final Type arraysType;
 196     public final Type iterableType;
 197     public final Type iteratorType;
 198     public final Type annotationTargetType;
 199     public final Type overrideType;
 200     public final Type retentionType;
 201     public final Type deprecatedType;
 202     public final Type suppressWarningsType;
 203     public final Type supplierType;
 204     public final Type inheritedType;
 205     public final Type profileType;
 206     public final Type proprietaryType;
 207     public final Type systemType;
 208     public final Type autoCloseableType;
 209     public final Type trustMeType;
 210     public final Type lambdaMetafactory;
 211     public final Type stringConcatFactory;
 212     public final Type repeatableType;
 213     public final Type documentedType;
 214     public final Type elementTypeType;
 215     public final Type functionalInterfaceType;
 216 
 217     /** The symbol representing the length field of an array.
 218      */
 219     public final VarSymbol lengthVar;
 220 
 221     /** The symbol representing the final finalize method on enums */
 222     public final MethodSymbol enumFinalFinalize;
 223 
 224     /** The symbol representing the close method on TWR AutoCloseable type */
 225     public final MethodSymbol autoCloseableClose;
 226 
 227     /** The predefined type that belongs to a tag.
 228      */
 229     public final Type[] typeOfTag = new Type[TypeTag.getTypeTagCount()];
 230 
 231     /** The name of the class that belongs to a basic type tag.
 232      */
 233     public final Name[] boxedName = new Name[TypeTag.getTypeTagCount()];
 234 
 235     /** A hashtable containing the encountered top-level and member classes,
 236      *  indexed by flat names. The table does not contain local classes.
 237      *  It should be updated from the outside to reflect classes defined
 238      *  by compiled source files.
 239      */
 240     private final Map<Name, Map<ModuleSymbol,ClassSymbol>> classes = new HashMap<>();
 241 
 242     /** A hashtable containing the encountered packages.
 243      *  the table should be updated from outside to reflect packages defined
 244      *  by compiled source files.
 245      */
 246     private final Map<Name, Map<ModuleSymbol,PackageSymbol>> packages = new HashMap<>();
 247 
 248     /** A hashtable giving the encountered modules.
 249      */
 250     private final Map<Name, ModuleSymbol> modules = new LinkedHashMap<>();
 251 
 252     private final Map<Types.UniqueType, VarSymbol> classFields = new HashMap<>();
 253 
 254     public VarSymbol getClassField(Type type, Types types) {
 255         return classFields.computeIfAbsent(
 256             new UniqueType(type, types), k -> {
 257                 Type arg = null;
 258                 if (type.getTag() == ARRAY || type.getTag() == CLASS)
 259                     arg = types.erasure(type);
 260                 else if (type.isPrimitiveOrVoid())
 261                     arg = types.boxedClass(type).type;
 262                 else
 263                     throw new AssertionError(type);
 264 
 265                 Type t = new ClassType(
 266                     classType.getEnclosingType(), List.of(arg), classType.tsym);
 267                 return new VarSymbol(
 268                     STATIC | PUBLIC | FINAL, names._class, t, type.tsym);
 269             });
 270     }
 271 
 272     public void initType(Type type, ClassSymbol c) {
 273         type.tsym = c;
 274         typeOfTag[type.getTag().ordinal()] = type;
 275     }
 276 
 277     public void initType(Type type, String name) {
 278         initType(
 279             type,
 280             new ClassSymbol(
 281                 PUBLIC, names.fromString(name), type, rootPackage));
 282     }
 283 
 284     public void initType(Type type, String name, String bname) {
 285         initType(type, name);
 286         boxedName[type.getTag().ordinal()] = names.fromString("java.lang." + bname);
 287     }
 288 
 289     /** The class symbol that owns all predefined symbols.
 290      */
 291     public final ClassSymbol predefClass;
 292 
 293     /** Enter a class into symbol table.
 294      *  @param s The name of the class.
 295      */
 296     private Type enterClass(String s) {
 297         return enterClass(java_base, names.fromString(s)).type;
 298     }
 299 
 300     public void synthesizeEmptyInterfaceIfMissing(final Type type) {
 301         final Completer completer = type.tsym.completer;
 302         type.tsym.completer = new Completer() {
 303             @Override
 304             public void complete(Symbol sym) throws CompletionFailure {
 305                 try {
 306                     completer.complete(sym);
 307                 } catch (CompletionFailure e) {
 308                     sym.flags_field |= (PUBLIC | INTERFACE);
 309                     ((ClassType) sym.type).supertype_field = objectType;
 310                 }
 311             }
 312 
 313             @Override
 314             public boolean isTerminal() {
 315                 return completer.isTerminal();
 316             }
 317         };
 318     }
 319 
 320     public void synthesizeBoxTypeIfMissing(final Type type) {
 321         ClassSymbol sym = enterClass(java_base, boxedName[type.getTag().ordinal()]);
 322         final Completer completer = sym.completer;
 323         sym.completer = new Completer() {
 324             @Override
 325             public void complete(Symbol sym) throws CompletionFailure {
 326                 try {
 327                     completer.complete(sym);
 328                 } catch (CompletionFailure e) {
 329                     sym.flags_field |= PUBLIC;
 330                     ((ClassType) sym.type).supertype_field = objectType;
 331                     MethodSymbol boxMethod =
 332                         new MethodSymbol(PUBLIC | STATIC, names.valueOf,
 333                                          new MethodType(List.of(type), sym.type,
 334                                 List.nil(), methodClass),
 335                             sym);
 336                     sym.members().enter(boxMethod);
 337                     MethodSymbol unboxMethod =
 338                         new MethodSymbol(PUBLIC,
 339                             type.tsym.name.append(names.Value), // x.intValue()
 340                             new MethodType(List.nil(), type,
 341                                 List.nil(), methodClass),
 342                             sym);
 343                     sym.members().enter(unboxMethod);
 344                 }
 345             }
 346 
 347             @Override
 348             public boolean isTerminal() {
 349                 return completer.isTerminal();
 350             }
 351         };
 352     }
 353 
 354     // Enter a synthetic class that is used to mark classes in ct.sym.
 355     // This class does not have a class file.
 356     private Type enterSyntheticAnnotation(String name) {
 357         // for now, leave the module null, to prevent problems from synthesizing the
 358         // existence of a class in any specific module, including noModule
 359         ClassType type = (ClassType)enterClass(java_base, names.fromString(name)).type;
 360         ClassSymbol sym = (ClassSymbol)type.tsym;
 361         sym.completer = Completer.NULL_COMPLETER;
 362         sym.flags_field = PUBLIC|ACYCLIC|ANNOTATION|INTERFACE;
 363         sym.erasure_field = type;
 364         sym.members_field = WriteableScope.create(sym);
 365         type.typarams_field = List.nil();
 366         type.allparams_field = List.nil();
 367         type.supertype_field = annotationType;
 368         type.interfaces_field = List.nil();
 369         return type;
 370     }
 371 
 372     /** Constructor; enters all predefined identifiers and operators
 373      *  into symbol table.
 374      */
 375     protected Symtab(Context context) throws CompletionFailure {
 376         context.put(symtabKey, this);
 377 
 378         names = Names.instance(context);
 379 
 380         // Create the unknown type
 381         unknownType = new UnknownType();
 382 
 383         messages = JavacMessages.instance(context);
 384 
 385         rootPackage = new PackageSymbol(names.empty, null);
 386 
 387         // create the basic builtin symbols
 388         unnamedModule = new ModuleSymbol(names.empty, null) {
 389                 {
 390                     directives = List.nil();
 391                     exports = List.nil();
 392                     provides = List.nil();
 393                     uses = List.nil();
 394                     ModuleSymbol java_base = enterModule(names.java_base);
 395                     com.sun.tools.javac.code.Directive.RequiresDirective d =
 396                             new com.sun.tools.javac.code.Directive.RequiresDirective(java_base,
 397                                     EnumSet.of(com.sun.tools.javac.code.Directive.RequiresFlag.MANDATED));
 398                     requires = List.of(d);
 399                 }
 400                 @Override
 401                 public String toString() {
 402                     return messages.getLocalizedString("compiler.misc.unnamed.module");
 403                 }
 404             };
 405         addRootPackageFor(unnamedModule);
 406         unnamedModule.enclosedPackages = unnamedModule.enclosedPackages.prepend(unnamedModule.unnamedPackage);
 407 
 408         errModule = new ModuleSymbol(names.empty, null) {
 409                 {
 410                     directives = List.nil();
 411                     exports = List.nil();
 412                     provides = List.nil();
 413                     uses = List.nil();
 414                     ModuleSymbol java_base = enterModule(names.java_base);
 415                     com.sun.tools.javac.code.Directive.RequiresDirective d =
 416                             new com.sun.tools.javac.code.Directive.RequiresDirective(java_base,
 417                                     EnumSet.of(com.sun.tools.javac.code.Directive.RequiresFlag.MANDATED));
 418                     requires = List.of(d);
 419                 }
 420             };
 421         addRootPackageFor(errModule);
 422 
 423         noModule = new ModuleSymbol(names.empty, null) {
 424             @Override public boolean isNoModule() {
 425                 return true;
 426             }
 427         };
 428         addRootPackageFor(noModule);
 429 
 430         noSymbol = new TypeSymbol(NIL, 0, names.empty, Type.noType, rootPackage) {
 431             @Override @DefinedBy(Api.LANGUAGE_MODEL)
 432             public <R, P> R accept(ElementVisitor<R, P> v, P p) {
 433                 return v.visitUnknown(this, p);
 434             }
 435         };
 436 
 437         // create the error symbols
 438         errSymbol = new ClassSymbol(PUBLIC|STATIC|ACYCLIC, names.any, null, rootPackage);
 439         errType = new ErrorType(errSymbol, Type.noType);
 440 
 441         unknownSymbol = new ClassSymbol(PUBLIC|STATIC|ACYCLIC, names.fromString("<any?>"), null, rootPackage);
 442         unknownSymbol.members_field = new Scope.ErrorScope(unknownSymbol);
 443         unknownSymbol.type = unknownType;
 444 
 445         // initialize builtin types
 446         initType(byteType, "byte", "Byte");
 447         initType(shortType, "short", "Short");
 448         initType(charType, "char", "Character");
 449         initType(intType, "int", "Integer");
 450         initType(longType, "long", "Long");
 451         initType(floatType, "float", "Float");
 452         initType(doubleType, "double", "Double");
 453         initType(booleanType, "boolean", "Boolean");
 454         initType(voidType, "void", "Void");
 455         initType(botType, "<nulltype>");
 456         initType(errType, errSymbol);
 457         initType(unknownType, unknownSymbol);
 458 
 459         // the builtin class of all arrays
 460         arrayClass = new ClassSymbol(PUBLIC|ACYCLIC, names.Array, noSymbol);
 461 
 462         // VGJ
 463         boundClass = new ClassSymbol(PUBLIC|ACYCLIC, names.Bound, noSymbol);
 464         boundClass.members_field = new Scope.ErrorScope(boundClass);
 465 
 466         // the builtin class of all methods
 467         methodClass = new ClassSymbol(PUBLIC|ACYCLIC, names.Method, noSymbol);
 468         methodClass.members_field = new Scope.ErrorScope(boundClass);
 469 
 470         // Create class to hold all predefined constants and operations.
 471         predefClass = new ClassSymbol(PUBLIC|ACYCLIC, names.empty, rootPackage);
 472         WriteableScope scope = WriteableScope.create(predefClass);
 473         predefClass.members_field = scope;
 474 
 475         // Get the initial completer for Symbols from the ClassFinder
 476         initialCompleter = ClassFinder.instance(context).getCompleter();
 477         rootPackage.members_field = WriteableScope.create(rootPackage);
 478 
 479         // Enter symbols for basic types.
 480         scope.enter(byteType.tsym);
 481         scope.enter(shortType.tsym);
 482         scope.enter(charType.tsym);
 483         scope.enter(intType.tsym);
 484         scope.enter(longType.tsym);
 485         scope.enter(floatType.tsym);
 486         scope.enter(doubleType.tsym);
 487         scope.enter(booleanType.tsym);
 488         scope.enter(errType.tsym);
 489 
 490         // Enter symbol for the errSymbol
 491         scope.enter(errSymbol);
 492 
 493         Source source = Source.instance(context);
 494         if (Feature.MODULES.allowedInSource(source)) {
 495             java_base = enterModule(names.java_base);
 496             //avoid completing java.base during the Symtab initialization
 497             java_base.completer = Completer.NULL_COMPLETER;
 498             java_base.visiblePackages = Collections.emptyMap();
 499         } else {
 500             java_base = noModule;
 501         }
 502 
 503         // Get the initial completer for ModuleSymbols from Modules
 504         moduleCompleter = Modules.instance(context).getCompleter();
 505 
 506         // Enter predefined classes. All are assumed to be in the java.base module.
 507         objectType = enterClass("java.lang.Object");
 508         objectsType = enterClass("java.util.Objects");
 509         classType = enterClass("java.lang.Class");
 510         stringType = enterClass("java.lang.String");
 511         stringBufferType = enterClass("java.lang.StringBuffer");
 512         stringBuilderType = enterClass("java.lang.StringBuilder");
 513         cloneableType = enterClass("java.lang.Cloneable");
 514         throwableType = enterClass("java.lang.Throwable");
 515         serializableType = enterClass("java.io.Serializable");
 516         serializedLambdaType = enterClass("java.lang.invoke.SerializedLambda");
 517         varHandleType = enterClass("java.lang.invoke.VarHandle");
 518         methodHandleType = enterClass("java.lang.invoke.MethodHandle");
 519         methodHandleLookupType = enterClass("java.lang.invoke.MethodHandles$Lookup");
 520         methodTypeType = enterClass("java.lang.invoke.MethodType");
 521         errorType = enterClass("java.lang.Error");
 522         illegalArgumentExceptionType = enterClass("java.lang.IllegalArgumentException");
 523         interruptedExceptionType = enterClass("java.lang.InterruptedException");
 524         exceptionType = enterClass("java.lang.Exception");
 525         runtimeExceptionType = enterClass("java.lang.RuntimeException");
 526         classNotFoundExceptionType = enterClass("java.lang.ClassNotFoundException");
 527         noClassDefFoundErrorType = enterClass("java.lang.NoClassDefFoundError");
 528         noSuchFieldErrorType = enterClass("java.lang.NoSuchFieldError");
 529         assertionErrorType = enterClass("java.lang.AssertionError");
 530         incompatibleClassChangeErrorType = enterClass("java.lang.IncompatibleClassChangeError");
 531         cloneNotSupportedExceptionType = enterClass("java.lang.CloneNotSupportedException");
 532         annotationType = enterClass("java.lang.annotation.Annotation");
 533         classLoaderType = enterClass("java.lang.ClassLoader");
 534         enumSym = enterClass(java_base, names.java_lang_Enum);
 535         enumFinalFinalize =
 536             new MethodSymbol(PROTECTED|FINAL|HYPOTHETICAL,
 537                              names.finalize,
 538                              new MethodType(List.nil(), voidType,
 539                                             List.nil(), methodClass),
 540                              enumSym);
 541         listType = enterClass("java.util.List");
 542         collectionsType = enterClass("java.util.Collections");
 543         comparableType = enterClass("java.lang.Comparable");
 544         comparatorType = enterClass("java.util.Comparator");
 545         arraysType = enterClass("java.util.Arrays");
 546         iterableType = enterClass("java.lang.Iterable");
 547         iteratorType = enterClass("java.util.Iterator");
 548         annotationTargetType = enterClass("java.lang.annotation.Target");
 549         overrideType = enterClass("java.lang.Override");
 550         retentionType = enterClass("java.lang.annotation.Retention");
 551         deprecatedType = enterClass("java.lang.Deprecated");
 552         suppressWarningsType = enterClass("java.lang.SuppressWarnings");
 553         supplierType = enterClass("java.util.function.Supplier");
 554         inheritedType = enterClass("java.lang.annotation.Inherited");
 555         repeatableType = enterClass("java.lang.annotation.Repeatable");
 556         documentedType = enterClass("java.lang.annotation.Documented");
 557         elementTypeType = enterClass("java.lang.annotation.ElementType");
 558         systemType = enterClass("java.lang.System");
 559         autoCloseableType = enterClass("java.lang.AutoCloseable");
 560         autoCloseableClose = new MethodSymbol(PUBLIC,
 561                              names.close,
 562                              new MethodType(List.nil(), voidType,
 563                                             List.of(exceptionType), methodClass),
 564                              autoCloseableType.tsym);
 565         trustMeType = enterClass("java.lang.SafeVarargs");
 566         nativeHeaderType = enterClass("java.lang.annotation.Native");
 567         lambdaMetafactory = enterClass("java.lang.invoke.LambdaMetafactory");
 568         stringConcatFactory = enterClass("java.lang.invoke.StringConcatFactory");
 569         functionalInterfaceType = enterClass("java.lang.FunctionalInterface");
 570 
 571         synthesizeEmptyInterfaceIfMissing(autoCloseableType);
 572         synthesizeEmptyInterfaceIfMissing(cloneableType);
 573         synthesizeEmptyInterfaceIfMissing(serializableType);
 574         synthesizeEmptyInterfaceIfMissing(lambdaMetafactory);
 575         synthesizeEmptyInterfaceIfMissing(serializedLambdaType);
 576         synthesizeEmptyInterfaceIfMissing(stringConcatFactory);
 577         synthesizeBoxTypeIfMissing(doubleType);
 578         synthesizeBoxTypeIfMissing(floatType);
 579         synthesizeBoxTypeIfMissing(voidType);
 580 
 581         // Enter a synthetic class that is used to mark internal
 582         // proprietary classes in ct.sym.  This class does not have a
 583         // class file.
 584         proprietaryType = enterSyntheticAnnotation("sun.Proprietary+Annotation");
 585 
 586         // Enter a synthetic class that is used to provide profile info for
 587         // classes in ct.sym.  This class does not have a class file.
 588         profileType = enterSyntheticAnnotation("jdk.Profile+Annotation");
 589         MethodSymbol m = new MethodSymbol(PUBLIC | ABSTRACT, names.value, intType, profileType.tsym);
 590         profileType.tsym.members().enter(m);
 591 
 592         // Enter a class for arrays.
 593         // The class implements java.lang.Cloneable and java.io.Serializable.
 594         // It has a final length field and a clone method.
 595         ClassType arrayClassType = (ClassType)arrayClass.type;
 596         arrayClassType.supertype_field = objectType;
 597         arrayClassType.interfaces_field = List.of(cloneableType, serializableType);
 598         arrayClass.members_field = WriteableScope.create(arrayClass);
 599         lengthVar = new VarSymbol(
 600             PUBLIC | FINAL,
 601             names.length,
 602             intType,
 603             arrayClass);
 604         arrayClass.members().enter(lengthVar);
 605         arrayCloneMethod = new MethodSymbol(
 606             PUBLIC,
 607             names.clone,
 608             new MethodType(List.nil(), objectType,
 609                            List.nil(), methodClass),
 610             arrayClass);
 611         arrayClass.members().enter(arrayCloneMethod);
 612 
 613         if (java_base != noModule)
 614             java_base.completer = moduleCompleter::complete; //bootstrap issues
 615 
 616     }
 617 
 618     /** Define a new class given its name and owner.
 619      */
 620     public ClassSymbol defineClass(Name name, Symbol owner) {
 621         ClassSymbol c = new ClassSymbol(0, name, owner);
 622         c.completer = initialCompleter;
 623         return c;
 624     }
 625 
 626     /** Create a new toplevel or member class symbol with given name
 627      *  and owner and enter in `classes' unless already there.
 628      */
 629     public ClassSymbol enterClass(ModuleSymbol msym, Name name, TypeSymbol owner) {
 630         Assert.checkNonNull(msym);
 631         Name flatname = TypeSymbol.formFlatName(name, owner);
 632         ClassSymbol c = getClass(msym, flatname);
 633         if (c == null) {
 634             c = defineClass(name, owner);
 635             doEnterClass(msym, c);
 636         } else if ((c.name != name || c.owner != owner) && owner.kind == TYP && c.owner.kind == PCK) {
 637             // reassign fields of classes that might have been loaded with
 638             // their flat names.
 639             c.owner.members().remove(c);
 640             c.name = name;
 641             c.owner = owner;
 642             c.fullname = ClassSymbol.formFullName(name, owner);
 643         }
 644         return c;
 645     }
 646 
 647     public ClassSymbol getClass(ModuleSymbol msym, Name flatName) {
 648         Assert.checkNonNull(msym, flatName::toString);
 649         return classes.getOrDefault(flatName, Collections.emptyMap()).get(msym);
 650     }
 651 
 652     public PackageSymbol lookupPackage(ModuleSymbol msym, Name flatName) {
 653         Assert.checkNonNull(msym);
 654 
 655         if (flatName.isEmpty()) {
 656             //unnamed packages only from the current module - visiblePackages contains *root* package, not unnamed package!
 657             return msym.unnamedPackage;
 658         }
 659 
 660         if (msym == noModule) {
 661             return enterPackage(msym, flatName);
 662         }
 663 
 664         msym.complete();
 665 
 666         PackageSymbol pack;
 667 
 668         pack = msym.visiblePackages.get(flatName);
 669 
 670         if (pack != null)
 671             return pack;
 672 
 673         pack = getPackage(msym, flatName);
 674 
 675         if (pack != null && pack.exists())
 676             return pack;
 677 
 678         boolean dependsOnUnnamed = msym.requires != null &&
 679                                    msym.requires.stream()
 680                                                 .map(rd -> rd.module)
 681                                                 .anyMatch(mod -> mod == unnamedModule);
 682 
 683         if (dependsOnUnnamed) {
 684             //msyms depends on the unnamed module, for which we generally don't know
 685             //the list of packages it "exports" ahead of time. So try to lookup the package in the
 686             //current module, and in the unnamed module and see if it exists in one of them
 687             PackageSymbol unnamedPack = getPackage(unnamedModule, flatName);
 688 
 689             if (unnamedPack != null && unnamedPack.exists()) {
 690                 msym.visiblePackages.put(unnamedPack.fullname, unnamedPack);
 691                 return unnamedPack;
 692             }
 693 
 694             pack = enterPackage(msym, flatName);
 695             pack.complete();
 696             if (pack.exists())
 697                 return pack;
 698 
 699             unnamedPack = enterPackage(unnamedModule, flatName);
 700             unnamedPack.complete();
 701             if (unnamedPack.exists()) {
 702                 msym.visiblePackages.put(unnamedPack.fullname, unnamedPack);
 703                 return unnamedPack;
 704             }
 705 
 706             return pack;
 707         }
 708 
 709         return enterPackage(msym, flatName);
 710     }
 711 
 712     private static final Map<ModuleSymbol, ClassSymbol> EMPTY = new HashMap<>();
 713 
 714     public void removeClass(ModuleSymbol msym, Name flatName) {
 715         classes.getOrDefault(flatName, EMPTY).remove(msym);
 716     }
 717 
 718     public Iterable<ClassSymbol> getAllClasses() {
 719         return () -> Iterators.createCompoundIterator(classes.values(), v -> v.values().iterator());
 720     }
 721 
 722     private void doEnterClass(ModuleSymbol msym, ClassSymbol cs) {
 723         classes.computeIfAbsent(cs.flatname, n -> new HashMap<>()).put(msym, cs);
 724     }
 725 
 726     /** Create a new member or toplevel class symbol with given flat name
 727      *  and enter in `classes' unless already there.
 728      */
 729     public ClassSymbol enterClass(ModuleSymbol msym, Name flatname) {
 730         Assert.checkNonNull(msym);
 731         PackageSymbol ps = lookupPackage(msym, Convert.packagePart(flatname));
 732         Assert.checkNonNull(ps);
 733         Assert.checkNonNull(ps.modle);
 734         ClassSymbol c = getClass(ps.modle, flatname);
 735         if (c == null) {
 736             c = defineClass(Convert.shortName(flatname), ps);
 737             doEnterClass(ps.modle, c);
 738             return c;
 739         } else
 740             return c;
 741     }
 742 
 743     /** Check to see if a package exists, given its fully qualified name.
 744      */
 745     public boolean packageExists(ModuleSymbol msym, Name fullname) {
 746         Assert.checkNonNull(msym);
 747         return lookupPackage(msym, fullname).exists();
 748     }
 749 
 750     /** Make a package, given its fully qualified name.
 751      */
 752     public PackageSymbol enterPackage(ModuleSymbol currModule, Name fullname) {
 753         Assert.checkNonNull(currModule);
 754         PackageSymbol p = getPackage(currModule, fullname);
 755         if (p == null) {
 756             Assert.check(!fullname.isEmpty(), () -> "rootPackage missing!; currModule: " + currModule);
 757             p = new PackageSymbol(
 758                     Convert.shortName(fullname),
 759                     enterPackage(currModule, Convert.packagePart(fullname)));
 760             p.completer = initialCompleter;
 761             p.modle = currModule;
 762             doEnterPackage(currModule, p);
 763         }
 764         return p;
 765     }
 766 
 767     private void doEnterPackage(ModuleSymbol msym, PackageSymbol pack) {
 768         packages.computeIfAbsent(pack.fullname, n -> new HashMap<>()).put(msym, pack);
 769         msym.enclosedPackages = msym.enclosedPackages.prepend(pack);
 770     }
 771 
 772     private void addRootPackageFor(ModuleSymbol module) {
 773         doEnterPackage(module, rootPackage);
 774         PackageSymbol unnamedPackage = new PackageSymbol(names.empty, rootPackage) {
 775                 @Override
 776                 public String toString() {
 777                     return messages.getLocalizedString("compiler.misc.unnamed.package");
 778                 }
 779             };
 780         unnamedPackage.modle = module;
 781         //we cannot use a method reference below, as initialCompleter might be null now
 782         unnamedPackage.completer = s -> initialCompleter.complete(s);
 783         module.unnamedPackage = unnamedPackage;
 784     }
 785 
 786     public PackageSymbol getPackage(ModuleSymbol module, Name fullname) {
 787         return packages.getOrDefault(fullname, Collections.emptyMap()).get(module);
 788     }
 789 
 790     public ModuleSymbol enterModule(Name name) {
 791         ModuleSymbol msym = modules.get(name);
 792         if (msym == null) {
 793             msym = ModuleSymbol.create(name, names.module_info);
 794             addRootPackageFor(msym);
 795             msym.completer = s -> moduleCompleter.complete(s); //bootstrap issues
 796             modules.put(name, msym);
 797         }
 798         return msym;
 799     }
 800 
 801     public ModuleSymbol getModule(Name name) {
 802         return modules.get(name);
 803     }
 804 
 805     //temporary:
 806     public ModuleSymbol inferModule(Name packageName) {
 807         if (packageName.isEmpty())
 808             return java_base == noModule ? noModule : unnamedModule;//!
 809 
 810         ModuleSymbol msym = null;
 811         Map<ModuleSymbol,PackageSymbol> map = packages.get(packageName);
 812         if (map == null)
 813             return null;
 814         for (Map.Entry<ModuleSymbol,PackageSymbol> e: map.entrySet()) {
 815             if (!e.getValue().members().isEmpty()) {
 816                 if (msym == null) {
 817                     msym = e.getKey();
 818                 } else {
 819                     return null;
 820                 }
 821             }
 822         }
 823         return msym;
 824     }
 825 
 826     public List<ModuleSymbol> listPackageModules(Name packageName) {
 827         if (packageName.isEmpty())
 828             return List.nil();
 829 
 830         List<ModuleSymbol> result = List.nil();
 831         Map<ModuleSymbol,PackageSymbol> map = packages.get(packageName);
 832         if (map != null) {
 833             for (Map.Entry<ModuleSymbol, PackageSymbol> e: map.entrySet()) {
 834                 if (!e.getValue().members().isEmpty()) {
 835                     result = result.prepend(e.getKey());
 836                 }
 837             }
 838         }
 839         return result;
 840     }
 841 
 842     public Collection<ModuleSymbol> getAllModules() {
 843         return modules.values();
 844     }
 845 
 846     public Iterable<ClassSymbol> getClassesForName(Name candidate) {
 847         return classes.getOrDefault(candidate, Collections.emptyMap()).values();
 848     }
 849 
 850     public Iterable<PackageSymbol> getPackagesForName(Name candidate) {
 851         return packages.getOrDefault(candidate, Collections.emptyMap()).values();
 852     }
 853 }